Behind the Study: COVID-19 and Chronological Aging

Dr. Michael P. Lisanti from The University of Salford describes his 2020 paper published by Aging, entitled, “COVID-19 and chronological aging: senolytics and other anti-aging drugs for the treatment or prevention of corona virus infection?

Researchers explain their studies that were published in Aging

Behind the Study is a series of transcribed videos from researchers elaborating on their recent oncology-focused studies published by Aging. A new Behind the Study is released each Monday. Visit the Aging YouTube channel for more insights from outstanding authors.

Hi, I’m professor Michael Lisanti and I’m the Chair of Translational Medicine at the University of Salford, and today I want to talk about our new prospective article, which links COVID-19 and chronological aging, and is focused on potential treatments and prevention strategies. I got interested in this topic because there seems to be an association between COVID-19 fatalities and aging, especially in patients with advanced chronological age. Patients over 65, and their 70s and 80s, are more likely to have increased morbidity and mortality. And so, I thought there may be a link there, between aging and senescence and the viral replication, as well as the potential therapy.

What I’d like to highlight about this particular article is that it proposes potential treatment strategies as well as prevention strategies. The reason is because it appears that this disease, the virus itself, may target senescent cells and senescent cells have been rewired to increase protein synthesis and also to increase the secretion of inflammatory mediators, which is known as the SASP, the senescence-associated secretory phenotype.

And so, one idea would be to use drugs that are senolytics. Senolytics are drugs that target and lyse senescent cells, but also to use protein synthesis inhibitors. The reason is because proteins synthesis inhibitors and senolytic drugs would prevent viral replication, which would reduce viral transmission. And so this could be used as a preventative strategy. I’ll just give you a couple of examples. If you have a drug which is an FDA-approved protein synthesis inhibitor, it should inhibit the secretion of inflammatory mediators, like IL-6. It should inhibit the fibrosis by preventing the secretion and production of collagen. And most importantly, the virus is also made of protein, so if you have a protein synthesis inhibitor, it will also inhibit viral replication.

Figure 1. What is the relationship between COVID-19 and advanced chronological age?
Figure 1. What is the relationship between COVID-19 and advanced chronological age?

There are three drugs I’d like to mention in particular. One is azithromycin, which is a senolytic. The others are also protein synthesis inhibitors, like doxycycline and rapamycin. All three have been shown to reduce IL-6 production because of their inhibition of protein synthesis activity. And also, all three of them have been shown to inhibit viral replication, not specifically of COVID 19, but since this effect on protein synthesis is a generalized effect, it should work for any virus. For example, azithromycin has been shown to inhibit the replication of Zika virus and Ebola virus, doxycycline has been shown to inhibit the replication of dengue virus, and rapamycin, which is another protein synthesis inhibitor with anti-aging properties, has been shown to inhibit replication of the HIV virus.

So, it seems to me that it’s a no-brainer that we should be repurposing FDA-approved drugs that are protein synthesis inhibitors, both for prevention, to prevent the inflammation fibrosis that’s occurring that’s killing people with COVID-19, and also to prevent the contagion by inhibiting viral replication. So I think this could provide a very inexpensive way forward because drugs like doxycyclin are only less than 10 cents a day, and could be used, as I said, for both prophylaxis and treatment. But, I think we need to use it early in the disease to prevent the fibrosis and inflammation, which makes them long, very inflexible and unable to expand and contract, and leads them to a fibrotic lung disease, which prevents patient recovery and could explain lethality of the disease.

I would like to directly engage with people to pick this up, to bring this forward as potential clinical trials. These clinical trials could be done directly in healthcare workers because they are the most vulnerable. In addition, they could be done in patients with advanced chronological age, or even with patients that are asymptomatic, that have been identified as the virus-positive. And it would be like a window trial where you would do viral titers first, and then you would give the drug and then you could also look at the viral titers after administering the drugs. So this would be a very easy, straightforward trial.

All the diagnostic tools for COVID-19 have already been identified and perfected, so all we need to do is interject FDA-approved drugs, which are protein synthesis inhibitors, to look at the eradication, the virus. So this would also be a very inexpensive clinical trial. But I would like to engage with infectious disease experts and virologists to help facilitate. Thank you.

Of course, I would like to thank two foundations which have supported our work: The Fox Point Foundation in Canada and The Healthy Life Foundation in the UK for providing the equipment and infrastructure at the University of Salford.

Click here to read the full paper, published by Aging.

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Aging is an open-access journal that publishes research papers monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

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Behind the Study: Interview with Dr. Gil Atzmon

Dr. Gil Atzmon from the Albert Einstein College of Medicine discusses his 2017 study published by Aging, entitled, “The complex genetics of gait speed: genome-wide meta-analysis approach.”

Researchers explain their studies that were published in Aging
Researchers explain their studies that were published in Aging

Speaker

Welcome to the Aging YouTube channel. This interview is with Dr. Gil Atzmon in the department of medicine and genetics at the Albert Einstein College of Medicine in the Bronx, New York. (He is) also in the department of human biology and a faculty member of the Department of Natural Science at the University of Haifa in Haifa, Israel. (He is) talking about a manuscript published in Volume 9, Issue 1 of Aging titled, “The complex genetics of gait speed, genome-wide meta analysis approach.”

Dr. Gil Atzmon

So the paper that I’m talking about is, “The complex genetic of gait speed: genome-wide meta analysis approach.” And what we did here is to combine 21 studies around the world and try to figure out what is the genetic predisposition for gait speed. The idea was that if we are going by number, then we will find something because the size is a matter of the resolution that you can pinpoint the genetic variant that might have an effect on the phenotype that, in our case, is gait speed. So when you’re talking about challenges, think of do you have 21 people or 21 groups that you need to combine together and figure out how you harmonize the data that they provide you with and try to figure out what’s going on there. This is a challenge because it lasted for almost four years until we had the paper done and published.

But eventually what we found was great. Although what we expected to find once we started this endeavor, we thought we’d have variants that have genomic significance. Meaning, if you have this variant either you have a lower gait speed or you have higher gait speed or normal gait speed. And we’re talking about elderly people. That’s what we tried to figure out. We found out that we didn’t find such a variant, but we find other alternatives.

We try to use protein analysis, group analysis, pathway analysis on all kinds of stuff. And every time that we put the finger on such a different analysis, we found something, some other interesting views. As I said, for genetic variant we didn’t find any, meaning the closest that we have was 10 to the -7 when the threshold was 10 to the -8.

Figure 1. Manhattan plot of meta-analysis of genome wide association studies of gait speed for ~2.5 million genotype and imputed SNPs

But when you look at these genes, we found that there are a couple of them that have higher prevalence among the top hit. Again, they didn’t reach a significance, but the minute you have such a number in the top hits, you think it might be relevant. We have a HLA-DPB1, we have the POM121-L2, and so forth and so forth. And you can see in the paper to look at those variants.

The interesting idea I’m seeing of the observation was that there was a couple of hits that we saw only once, but they are hits such as the [inaudible 00:03:36] 12I02 with a peak, meaning there is aggregation of a couple of hits around this gene or inside this gene. Again, it tells us that this gene might be relevant to what we are looking for. When we did the pathway analysis we found a couple of them that are associated with diabetes, which if you think about it, that really can cause people to either have slow gait speed or higher gait speed. It depends on the disease that you have. We have a couple of hits in the pathway, and a lot of this link us to cancer. And again, the same thing. If you think about it, the minute you have a disease, your performance, in this case it’s gait speed, is either declined or increased.

So we can see in both cases, though we didn’t find the right hit, still what we found has some biological explanation. It also does expression analysis or expression QTL. QTL means that those genes that are associated with the expression of the genes didn’t code in the phenotype, we found a couple of them that were higher significance. Again, another example of what is the predisposition of those genes to the phenotype that we had.

So, all in all, we concluded that we found some relevant genetic predisposition for this phenotype. And although we didn’t find the exact variant that can say “if you have it, you have low speed, and if you don’t have it, you have a higher speed,” we think that if we’re looking at the story that we crafted, we think that we’ve found some ideas, some biological explanation which is what is inside this paper.

Speaker

Aging was launched in 2009 and is currently a traditional peer reviewed journal with free access which publishes in monthly issues. Topics include high impact research papers of general interest and biological significance in all fields of aging research, as well as topics beyond traditional gerontology. You can click on the link in the description below to order a reprint or read the manuscript that was discussed in this interview on aging-us.com. Please feel free to subscribe to our YouTube channel and connect with us on Facebook, Twitter, or LinkedIn. Thank you.

Click here to read the full paper, published by Aging.

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Aging is an open-access journal that publishes research papers monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

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Behind the Study: Interview with Dr. Marina P. Antoch

Dr. Marina Antoch of Roswell Park Comprehensive Cancer Center discusses her 2017 study published by Aging entitled, “Physiological frailty index (PFI): quantitative in-life estimate of individual biological age in mice.”

Researchers explain their studies that were published in Aging
Researchers explain their studies that were published in Aging

My name is Marina Antoch, and I am a member of Department of Pharmacology and Therapeutics for Roswell Park Cancer Institute. And actually working here at Roswell for 10 years now. Recently my group, in collaboration with few other laboratories and the local biotech startup company, Everon Biosciences, summarize the recent research in the paper that was published in the journal, Aging. This paper is related to working out a novel approach that will allow us to assess the overall health in the preclinical animal model organelle.

Working with the company that’s really interested in developing some therapeutics that could combat aging, slow down the aging, we really need to get some quantitative tools that we can use to assess the efficacy of those molecules of those potential drugs that they identify in their preclinical studies. There were few works that would suggest some approaches how we can do that, but none of these really satisfy the goals that we have.

So we have to think of some other approaches that we may use, and there were several requirements that we really need for developing the successful protocols. First of all, we wanted this protocol to be absolutely non-invasive for our preclinical animal models, so it could be repeated on the same subject for several times. We can actually look through the lifespan of the subject, how these parameters and overall health is changed with age. They have to be really quantitative. So we didn’t really want to rely on some observational things like the hair grain, for example, that’s been considered the hallmark of aging for many years. Many of these observations, they really require coring by several individual observers and then they are compared, and they’re very subjective. (We) really wanted to get something more objective that we could put in numbers.

This manuscript that was published actually summarized almost three-year work that was dedicated to this problem. We tried many different approaches and finally came up with a protocol that we called determining physiological frailty index. And this frailty index is just the cumulative estimate of many, many physiological parameters that are related to the health of the animal. And they’re very relevant to human studies since these such parameters as body weight or physical strength that we could measure, usually using special equipment or blood pressure that we can measure in animal models-very similar to how we do it in humans, blood cell parameters, and a few others that can really give us the quantitative assessment of each parameter. Then we compare how much it is in older animals – or in animals that don’t feel well. How much of these parameters differ from when compared to the younger animals, and that gave us a certain quantitative estimate. So why is that important? It’s important for the reason of testing, as I mentioned already, various potential biologicals that would be developed as anti-aging drugs.

Figure 1. Assessment of individual biological age of NIH Swiss mice

This protocol will now allow us to assess, quantitatively, the health status of animals then treat them with potential therapeutics, and then down the road, repeat this measurement to see if this frailty index, brought any improvement or not, and that would be indicative of the efficacy of the therapy. So this is one of the major goals of our research and why we developed this protocol. But for all future studies, we have actually another thought in mind, how we may use this particular approach. We’re now related to cancer research as you may know, due to the really successful development of many anti-cancer drugs, and many anti-cancer therapies. There are more and more cancer survivors. Actually in 2016, the American Cancer Society published statistics saying that there’s about 15 million people that went through the very harsh chemotherapeutic and radiation therapies. They are cancer-free. They never had relapsed cancer, but these therapies definitely affect a lot of other aspects of their health. And one of those aspects, besides any specific diseases, that they may develop is the accelerated aging.

With the development of more and more therapeutics, the expectation is that in 2026, there’ll be more than 20 million of cancer survivors. We’ll really need to be thinking about developing novel cancer therapeutics. We really should think not to make them more efficient and less toxic, but also to be able to diminish their damaging effect down the road at the latest stages of the life of basically to improve the quality of life of cancer survivors by adjusting the treatments at the time that we treat cancer. So we have less problems later on. To do that first, we have to test this in our preclinical models and for success of those tests, we really needed some quantitative assay that we can apply.

We think that our protocol of physiological frailty index would serve this purpose very well. So, basically, testing the efficacy and the therapeutic efficacy of different chemotherapeutic drugs. We may also look on a long-term effects to see how that affects animals health and adjust treatments based on the preclinical evaluation. This is why we think it’s really an important tool that could be very useful in many aspects of preclinical studies, and maybe sometimes applied then as many of preclinical studies translated into the clinical applications.

I’m also thinking that it may be very relevant for treatment of childhood cancers. Childhood cancers are very specific type of cancers. First of all, the regiments are actually the same as are worked out for adult people. Although young people and adult people are very different physiologically. They’re just adjusted by the weight, the age a little bit. But in principle, they are about the same.

The rate of cure for some types of childhood cancers nowadays is also pretty sufficient. So there is a large population of kids that went through chemotherapy and radiation that was applied to a very critical moment in their development. So they are effective. It’s really very significant. Actually the longevity of those childhood cancer survivors is statistically lower and they will premature age and develop a lot of different complications. So I think that that could be particularly important for treating various types of childhood cancers, and that can really affect the way we are treating childhood malignancies.

If we are able to reach our goal and adjust the treatment so we’re focusing not only on immediate therapeutic effect, but take into account these long-term complications that would inevitably arise after the treatment, we can significantly improve the quality of life of cancer survivors. That would be a very significant impact on the overall health of the population, I would say.

Click here to read the full study published by Aging.

Aging is an open-access journal that publishes research papers monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact media@impactjournals.com.

Behind the Study: Potential Reversal of Epigenetic Age Using Diet and Lifestyle

Dr. Kara Fitzgerald details her publication by Aging, entitled, “Potential reversal of epigenetic age using a diet and lifestyle intervention: a pilot randomized clinical trial“.

Researchers explain their studies that were published in Aging

Behind the Study is a series of transcribed videos from researchers elaborating on their recent oncology-focused studies published by Aging. A new Behind the Study is released each Monday. Visit the Aging YouTube channel for more insights from outstanding authors.

Listen to an audio version of this post

Hi, I am Kara Fitzgerald. I’m on faculty at The Institute for Functional Medicine. I have a clinic practice in Newtown, Connecticut. The title of our paper is “Potential reversal of epigenetic age using a diet and lifestyle intervention: a pilot randomized clinical trial“.

We became interested in epigenetics because we practice functional medicine. So we’re concerned with genetic expression. Particularly, I would say that my first big wake-up call came from the research in cancer, epigenetics where the tumor micro environment hijacks epigenetic expression kind of takes over hypermethylating tumor suppressor genes, turning on oncogenes, et cetera. Our question became if we are pushing methylation forward with high dose methyl donors such as full later B12, could we be influencing cancer, epigenetics at all? That and a few other reasons prompted us to develop the diet and lifestyle intervention and try a very nutrition forward approach to changing epigenetic expression.

However, we can’t get an Illumina EPIC array in clinical practice. And so once we designed the program and started to use it in clinical practice, the next question was: Are we making a difference at all, in epigenetic expression? We were given an unrestricted grant by Metagenics. Metagenics is a professional supplement company out of California so they were not involved in study design. They had no control over the study and/or findings or investment in products that we used.

We hired Helfgott Research Institute out of National University of Natural Medicine to run our study. So I, myself and my colleague Romilly Hodges who designed the program, we were not involved in the execution of the program. So that’s a little bit of the background. And what we did was we had a pilot study. We looked at men between the ages of 50 and 72.

We didn’t include women, because at that age range … so, we wanted to look at middle-age when we know DNA methylation starts to go awry, global hypomethylation with those regions of aberrant hypermethylation … so that was the time we wanted to look at, but we didn’t have enough money to have a larger population. So if we included women in that age range, we would have premenopausal perimenopause and post-menopausal subjects, and it would be difficult for us to tease out that influence on the findings. So we decided in our pilot to just go with men and we did our eight-week diet and lifestyle intervention. The diet is again, designed specifically to influence methylation. It’s very methyl, donor dense. There are a lot of greens. There are other nutrients that can influence the methylation cycle, such as beets, choline from eggs.

Figure 1. CONSORT 2010 flow diagram.

We encouraged people to have liver a few times a week, which is high again in folate and B12. We also included a lot of the polyphenols that have preclinical data on them for influencing DNMT and Tet enzymes. In fact, a lot of really interesting research, again, going back to cancer, epigenetics, and these polyphenols actually influencing the re-expression of hypermethylated and inhibited tumor suppressor genes. So we were interested in that particularly because a lot of those polyphenols actually have very long traditional use history. So for instance, curcumin or EGCG or resveratrol, luteolin, lutein, ellagic acid, quercetin. When you look into traditional medicine, we see of course millennia long use for green tea and curcumin by way of example, but they’re all pleiotropic in their effect: Anti-inflammatory, antioxidant, anti-tumor agenetic, et cetera. And at least some of those mechanisms I suspect are driven by epigenetic changes.

So diet heavy methyl donors, but also these methylation augmenting polyphenols. We included an exercise prescription, which was at least five days for 30 minutes at a perceived exertion of 60 to 80%. So not necessarily intense. We tracked sleep and encouraged them to get at least seven hours per night and gave them some basic sleep hygiene tips as they requested. There was a meditation intervention as well. So everything that we did has some evidence in the literature, either in clinical studies or preclinical of influencing favorably DNA methylation. We use two supplements, a prebiotic lactobacillus plantarum. We did that specifically because there’s some evidence that lactobacillus plantarium may increase that endogenous microbial production of folate, of natural folates. And we also included a greens powder. So again, the polyphenols that I just mentioned, those in a concentrated powder and our participants took each of those supplements twice a day.

Outcome, we looked at the EPIC Illumina array. We looked at a host of blood biomarkers, subjective questionnaires. Our chief finding, our most exciting finding, was using Horvath … we collected saliva and then using Horvath’s 2013 DNA methylation biological clock we showed a significant reversal of biological age in our subjects by 3.23 years as compared to the control group and that was a P value of 0.018. The within group change in our study participants was 1.96 years, so almost 2 years with a trend towards significance. The P value there is 0.066, so super excited about that finding. We’ve got more to unpack on the Illumina array. Triglycerides dropped in our study participants and LDL dropped in the study participants. Now I should state, I didn’t mention at the beginning, but these were healthy men, not on medication. We had a pretty strict criteria for enrollment.

It actually took us a while. We started this study in 2017. It took us quite a while to enroll because the program was rigorous and the selection process was relatively involved. Circulating folate, circulating methylfolate increased also in our study participants. I think that covers most of it.

We worked with nutritionists. This is another good point. Again, the program is rigorous and we had nutritionists support the study participants. They didn’t do any coaching. They actually just had an IRB approved script where they asked them if they had questions on the diet and then questions on exercise, et cetera, et cetera. So they were required to have some contact with the nutritionists. We had high adherence findings, and I look forward to publishing those and just exploring it. Nutrition interventions are notoriously poor, and I think we actually did well. I suspect it’s because we had these nutrition contact points with the subjects. To my knowledge, it’s the first of its kind study, randomized control study.

It was a double blind obviously, but it was a randomized control study where we had 20 in the control group and 18 in the study group, what else? It was eight weeks in duration. The other diet intervention, as we wrote about in the paper is the new age study and that was a Mediterranean diet over the course of the year. And they had some interesting epigenetic DNA methylation changes and a subgroup of that population did have lowering of biological age.

I want to thank Metagenics for their grant. I want to thank our team. Again, we worked with Helfgott Research Institute, National University of Natural Medicine in Portland, Oregon. My Co-PI from Helfgott is Ryan Bradley, statistician from Helfgott is Douglas Hanes. Emily Stack was the study manager. My team included Romilly Hodges, who is the nutrition director here at our clinic. She helped design. She and I designed the program. The other nutritionists involved are Janine HenkelMelissa TwedtDespina GiannopoulouJosette Herdell and Sally Logan. At McGill are Dr. Moshe Szyf and David Cheishvili, both helped with data analysis, particularly of the Illumina EPIC array. And Dr. Szyf also helped with study design.

So a big team, thank you to Dr. Steve Horvath and Dr. Josh Mitteldorf. Josh worked on Horvath, the DNA methylation clock analysis with some guidance from Steve Horvath. And so we’re deeply appreciative that work for us.

That’s our study. Our future is what we want to continue to look at this. I mean, this was our pilot study and we’d like to do a longer study, a larger study with men and women. So stay tuned, thank you.

Click here to read the full study published by Aging.

Click the links below for more information on corresponding author, Dr. Kara Fitzgerald:
Biological Aging Summary | Instagram | Facebook | Twitter | General Site | Younger You Program

Aging is an open-access journal that publishes research papers monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact media@impactjournals.com.

Behind the Study: Dr. Andrei Gudkov

Aging Editorial Board member Andrei V. Gudkov, PhD, DSci, discusses his 2017 research paper published by Aging, entitled, “p16(Ink4a) and senescence-associated β-galactosidase can be induced in macrophages as part of a reversible response to physiological stimuli.”

Researchers explain their studies that were published in Aging
Researchers explain their studies that were published in Aging

Behind the Study is a series of transcribed videos from researchers elaborating on their recent oncology-focused studies published in Aging. A new Behind the Study is released each Monday. Visit the Aging YouTube channel for more insights from outstanding authors.

Greetings. My name is Andrei Gudkov. I am working in Roswell Park Cancer Institute, designated cancer center located in Buffalo, New York. I am Senior Vice President for Basic Science and chair of Department of Cell Stress Biology. My research is focused on understanding of the mechanisms of deregulation of a variety of stress response pathways in cancer cells as well as in normal cells in relation to cancer origin, progression, or engraftment and trying to use the information which we are generating during this research to come up with new types of treatment of cancer or cancer prevention.

Recently, our interests have significantly switched towards studying of the mechanisms of aging in its relations to cancer, since, as we all know, both conditions are closely connected. During the last, probably 20 years, one of the central theories of aging in mammals has been evolving towards connection between chronic sterile inflammation, which is accumulating in tissues with age of a mammal, including humans, with systemic decline in regeneration capabilities, in function of organs and tissues, and increasing risk of major diseases, altogether known as aging-related diseases. And the source of this inflammation, its origin, has been the central focus of studies of many.

During last couple of years, the dominating opinion in the field is about the central role of senescent cells, cells which chose to stay irreversibly growth-arrested in response to DNA damage, which they acquire during their life. And, through that, change their phenotype in more significant way than just growth arrest, acquiring the ability to secrete a spectrum of pro-inflammatory factors.

These senescent cells, which initially were defined as such in tissue culture experiments, eventually were proclaimed to be the main suspects in their putative role of inflammation creators in aging organism. This idea has become really popular, especially following a series of brilliant works coming from number of laboratories, in which senescent cells were detected in vivo in mice and mouse models. And when these mice were treated with agents which eradicated these senescent cells, numerous signs of rejuvenation were observed.

I’m talking about the first paper of that kind appeared in 2011, Mayo Clinic, and the group led by Jim Kirkland and Jan van Deursen and a series of follow-up papers with similar results. In general, the idea of putting senescent cells in the position of the key sources of sterile chronic inflammation associated with aging came from Judy Campisi, who has provided the most important discoveries in that field.

Well, this theory is extremely appealing for many reasons. First, it is very well supported by evidence. Indeed, senescent cells, when they turn into senescents in culture, switch their phenotype into, so-called, SASPs, and that’s an associated secretory phenotype, the state in which cells continuously secrete pro-inflammatory factors. Second, these cells appear in culture as a result of serial passaging resembling aging. And, therefore, this link became kind of natural between aging and senescent cells. The presumption was that certain cells in the body who used up the number of divisions they can go through before they reach this state may be increasing with age and, therefore, these cells accumulate.

Each of them may become the source of sterile inflammation. Each single one provides a very weak signal, but, when they accumulate altogether, the impact may become significant and translated into pathological conditions. So recently, there were very few – and, even now, it is like that – very few biomarkers of senescent cells, none of which is very reliable because every single biomarker is kind of promiscuous and is not universally selective for senescent cells.

Among these biomarkers, two have been most popular. One is high level of expression of, so-called, senescent-associated senescent-associated beta-galactosidase, which can be detected chemically in fixed cells and tissues which undergo staining, including X-gal, which turn beta-galactosidase reaction into the blue dye under conditions which is not optimal for endogenous beta-galactosidases mammalian cells at low pH. And, under these conditions, the background beta-gal activity of normal cells is practically not seen and senescent cells become brightly visible. So this reaction, which unfortunately requires a cell… It can not be done on paraffin-embedded sections and require preservation of the enzymatic activity and, therefore, is available, mostly, on the frozen sections or in cells in culture… has been used very, very frequently. And in many papers, it has been just the only assay which was used for detection of so-called senescent cells.

Figure 1. Induction of p16Ink4a and SAβG in macrophages does not require p53.

The other biomarker, which resulted from a detailed analysis of promoters which are active selectively in senescent cells is the gene encoding cyclin-dependent kinase inhibitor p16. And the genes name is INK4a. In fact, this promoter of this gene is frequently upregulated in senescent cells, and it has relatively low background in other cells of the organism.

Again, p16 activation is not limited to senescent cells and, moreover, not every senescent cells has elevated p16, but that’s the best we have as of today. That is why, whenever the investigators want to create a mouse model in which they could have the desirable gene expressed exclusively in senescent cells, they use p16 promoter. And there are several mouse models; I’m aware of three in which reported constructs were put under p16 promoter. And the claim was that, when these reporters become obviously expressed in mouse tissues, that was interpreted as accumulation of senescent cells. Also, one can put under this promoter the gene which enables selective eradication of cells with this expression, and, therefore, there is an opportunity to selectively kill such cells. Again, this can be interpreted as a selective eradication of senescent cells.

Using these models, two groups of investigators claim that eradication of senescent cells in aged mice led to substantial demonstration of signs of rejuvenation and, in one case, with increased lifespan. Well, obviously, these data not only provided a very powerful support for the theory about the role of senescent cells in aging but also provided the proof of concept for development of pharmacological approaches to anti-aging treatment and treatment of conditions which lead to the high risk of development of age-related diseases, including cancer.

We obtained such mice in our laboratory, and we have been working with them during last couple of years. The mice we are using are coming from the laboratory of Norman Sharpless from North Carolina. And they have a luciferase reporter gene, which is substituting one of the alleles of p16 and, thereby, being expressed from the p16 promoter. We were pleased to see that these mice accumulate p16-driven luciferase-positive cells detected by in vivo imaging during their lives, which, actually, very well fit the senescent cell theory in their accumulation during life.

However, we were very surprised not seeing accumulation of these cells following total-body radiation or treatment with other genotoxic conditions, which, supposedly, should create lots of senescent cells. We also were puzzled that we were unable to see activation of p16-driven luciferase when we take tissues from these mice and isolated mesenchymal cells from these tissues in vitro and then turn them into senescents, and we failed to see activation of luciferase.

Again, all this together stimulated us to look at the nature of p16-positive cells in these mice and determined their nature, their origin, and their fate in vivo. We started from following the consequences of injection of cells, which would turn into senescents in vitro following injection in vivo into mice. And we labeled cells. We made cell senescents in culture by gum radiation. Then, we injected them intraperitoneal, subcutaneously, into mice. And we looked for their presence by monitoring the label which they were marked with.

Well, it appears that these labeled cells – their traces are disappearing quite quickly, and, within a few days, there are none left in the mice. However, if you put normal cells of similar origin, they actually last much longer. That was the first indication that there may be a mechanism of selective eradication of senescent cells in the body. To check this mechanism and one of our hypotheses was that this mechanism is associated with physical attack of some cells of immunity against senescent cells, and there’s supposed to be innate immunity because it’s happening immediately without any education over the organism.

Figure 5. Poly(I:C) abrogates elevated p16Ink4a expression in two independent in vivo models. 

We use a trick in which we embedded senescent cells created in vitro into algenate beads, small spheres consisting of a polymer, which enables to keep cells alive inside them, does not interfere with acquisition of nutrients and oxygen by the cells, but prevents any attack against the cells from any immunocytes. When we took these beads filled with senescent cells and put them in peritoneal cavity of mice, we were pleased to see that they are lasting four weeks without significant death, indicating that senescent cells, who disappear if they are injected without protective beads, are indeed killed by some, so far, unknown mechanism.

In order to identify the executors of senescent cells, we put these beads filled with senescent cells as bait inside, very peritoneal cavity of normal mice, and two weeks later, we pulled them out and analyzed who was accumulating in terms of how cells around these beads in lavage liquid, as well as in the capsule, which was formed around every bead.

Our results brought us to a very important and quite striking observational. The major part of the cells, which was so in these beads as well as in the lavage, appeared to be cells with macrophageal markers on them, which appeared to be bright fluorescence, meaning that they have activated p16, and also positive for beta-gal staining conducted under conditions we are using to reveal senescent cells. So we had to conclude that senescent cells put in the beads attract, probably, by the products of their secretion special subtypes of immune cells, significant proportion of which become reprogrammed to start expressing two biomarkers which people have been using to distinguish senescent cells.

We studied these macrophages in detail, and, after we published our first paper in which we describe this phenomenon, we published a second one, also in Aging, where their properties were described in further details. And we confident that these are bonafide macrophages, not only because they have have biomarkers, they have surface antigen specific for macrophages, but also they are capable of phagocytosis and, moreover, they can be selectively killed by liposome-embedded clodronate, a poison which only kills cells capable of phagocytosis. This killing could be done both in vitro and in vivo when you inject liposomal clodronate inside mice.

So, as far as the presence of these cells in the body of those mice which are not embedded with algenate beads with senescent cells, today, we are confident that these macrophages are accumulating in subcutaneous fat of aged mice in large numbers. And, again, they express biomarkers of macrophages that can be selectively eradicated by clodronate.

So, altogether, it means that the cells which become p16-positive vivo, not necessarily our senescent cells – our operations does not disprove that the signal which we and other investigators are seeing in these mice and increasing with age is not associated with senescent cells. So, potentially, certain proportion of cells we see are, indeed, senescent. However, we are confident that significant part of the signal goes from macrophages, which can be induced into the phenotype associated with expression of both senescent markers when they’re exposed to senescent cells. What is also interesting that this phenotype is reversible. And, in our second paper, we provide a number of physiological stimuli which can either stimulate or suppressed acquisition of this phenotype by macrophages.

All this, together, provides a very interesting step forward in evolution of the theory of aging associated with accumulation of certain specific cell types, contributing to the sterile inflammation occurring in tissues. Today, we can say that those cells which we claim to be the main source of that are not necessarily senescent, but also can be immunocytes who share with senescent cells some of their properties but are not senescent by nature and simply reprogrammed macrophages.

What is the relative impact of these macrophages versus senescent cells towards the process of aging is a very important question, not only from a theoretical standpoint, but also from practical standpoint because, from the time when senescent cells were claimed to be the key players of aging, there have been a substantial effort in the field in generating and testing senolytic compounds, drugs, emerging drugs, which potentially can have anti-aging effect due to eradication of senescent cells from the body.

Whether senolytic compounds would, indeed, solve the issue because, presumably, they will eliminate only a part of the p16-positive cells. To what extent, we need to redirect our attention to the senescent cell-associated macrophages as potential alternative source of secreted factors is an open question. And these are the questions which we are trying to address in our ongoing work, which stems from these observations. Thank you.

Click here to read the full study published in Aging.

Aging is an open-access journal that publishes research papers monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact media@impactjournals.com.

Aging is a proud participant in the AACR Annual Meeting 2021 #AACR21
Aging is a proud participant in the AACR Annual Meeting 2021 #AACR21

Behind the Study: Dr. Alex Zhavoronkov

Aging Editorial Board member Dr. Alex Zhavoronkov discusses his 2020 research paper published by Aging, entitled, “Geroprotective and senoremediative strategies to reduce the comorbidity, infection rates, severity, and lethality in gerophilic and gerolavic infections.”

Researchers explain their studies that were published in Aging
Researchers explain their studies that were published in Aging

Behind the Study is a series of transcribed videos from researchers elaborating on their recent oncology-focused studies published in Aging. A new Behind the Study is released each Monday. Visit the Aging YouTube channel for more insights from outstanding authors.

Hello, my name is Alex Zhavoronkov and I’m the Founder and CEO of a company called Insilico Medicine. We are focused on the latest applications of artificial intelligence to drug discovery, biomarker development, and aging research. And I’m also a Chief Scientist at the Biogerontology Research Foundation. It’s a UK-based charity, 12 years old now founded in 2008. It’s called the Biogerontology Research Foundation because it’s focused primarily on biological and biomedical gerontology with support research worldwide. And we also conduct policy outreach, policy documents, and promote aging research worldwide.

We got into the coronavirus theme in mid-January as a company and also as an extended group of collaborators. At Insilico, we decided to go directly after viral proteins. So we have the ability at Insilico to identify new targets, but also to generate normal compounds very quickly using generative cell networks and reinforcement learning. So it’s kind of imaginative and strategy oriented AI to create molecules that specifically bind to the proteins of interest.

So we originally published and put out the paper and the molecules for the 3C-like main protease of the SARS-CoV-2. And we’re working with multiple collaborators worldwide to provide the molecules for their proteins of interest, and also we are generating a bunch of others. However, for the purposes of this paper we are not using AI in any way. It’s human intelligence and it is quite obvious that SARS-CoV-2 is more harmful to the elderly, the people over 50. So it’s infecting more people over 50, it is a much more severe and much more lethal in that age group.

So that is why it’s actually pretty unique compared to other viruses. So if you look at influenza and the other common viruses we do not see another virus, we do not see such effects in the elderly, so it’s a little bit more equal opportunity infections. For SARS-CoV-2 it infects mostly the elderly and there is actually no term to describe it right now. So in the paper that I put forward in Aging, I propose a new term so it’s gerophilic and gerolavic infection from Greek géros, old man and epivlavís, harmful. So it’s more harmful to the elderly, more severe in elderly. And gerophilic it’s géros again old man and philia is love, so it loves old people.

And if we’ll look at the data from Wuhan in China, you will see that 90% of the population, 89.7% of the population, who got the virus were over 30. And 99.2% of the population that died of it were over 30. So it’s really uneven distribution for both severe cases and lethal cases in the population. And one of the really important case studies that has been studied quite extensively is the Diamond Princess cruise ship. So the world’s most watched lab that came into attention because a few thousand people got stuck, very diverse population group was stuck on one cruise boat. And out of those few thousand, around 700 contracted the virus and most of them were over 65 and there were originally seven deaths, and a few more people died.

Figure 1. COVID-19 as a gerophilic and gerolavic infection.

And we see that people who had the infection, even with mild symptoms, they have dark spots in their lungs on CT. So it looks like they have some lesions and there is some fibrosis. Even if the disease has mild symptoms, in the elderly more so, it leaves the fibrotic trace. And in the paper, I’m hypothesizing that the disease is associated with immunosenescence. So both the involution of the thymus and many other processes that lead to immunosenescence. Immunosenescence leads to infection, so here you have of course chances of death. Infection leads to more damage and loss of homeostasis and that leads to accelerated aging. And also acceleration of age-related pathology also increase the chances of death that lead to more immunosenescence. So it’s kind of the vicious circle of immunosenescence and infection.

And there have been many studies in the past showing that some of the geroprotectors like sirolimus, rapamycin, are maybe effective in potentiating response to vaccines and also preventing infection in the elderly. So it’s paradoxical observation that immunosuppressant, like rapamycin, might have immunostimulatory effects. And there was anecdotal evidence showing that it protects the elderly from influenza and other virus not infections. It’s pretty obvious to try something like rapamycin that is reasonably safe in low doses. So in high doses it has substantial side effects, but in low doses it’s very well tolerated.

So there are others what is called rapalogs, very famous one is called everolimus. It’s so very close structural analog to sirolimus, developed by Novartis which has claimed to be selective to specific coattails and outdoor complex that make it more beneficial for aging and for other diseases. However, I would really like to see more evidence of that because those are very close structural analogs and there are other inhibitors that serve the same purpose. So 2013, Novartis conducted few experiments with everolimus, the drug is called RAD001 and demonstrated that in healthy elderly patients a low dose treatment with RAD001. Results in even potentiation and less infection with influenza and also potentiation of vaccines. So that was promising news.

So they published in 2014 in Science Translational Medicine and it was very promising study. Then in 2018, they showed that a combination of everolimus and another ToR inhibitor also results in immune potentiation and prevention of several infections, primarily influenza. So for influenza, they published in Science Translational Medicine, and a spinoff out of Novartis took those molecules into clinic, into Phase 3. And in Phase 3, they decided to instead of using everolimus, they used the molecule called BEZ235 rebranded as RTB101 which had high concentrations. It’s also a PI-3K inhibitor, so it’s not a very selective inhibitor or ToR, and they failed in Phase 3.

But they haven’t used RAD001 or sirolimus in combination or as control. I believe that it’s likely to be because of the molecule and also patient selection, so it should be biomarker used for that. But those promising early experiments clinical studies with RAD001 and also substantial evidence from the clinic met-studies showing that rapamycin is potentiating a vaccine response and immune status in the elderly. That gives us very promising data to try sirolimus in Phase 3 in low doses maybe once a week, maybe in combination with other geroprotectors like metformin, like NAD boosters, like senolytic to potentiate the immune system of the elderly before they get sick.

So in this paper, I also want to highlight that it’s not a medical advice, it’s not a recommendation, it’s a call for a clinical trials of an alternative view on how to address COVID-19 also SARS-CoV-2 and prevent infection and increase survival in the elderly, and also make it less severe for the elderly. So in this paper, I’m calling for clinical trials of rapamycin, a very well known geroprotector. It was actually implicated in Aging by Professor Mikhail Blagosklonny at Roswell Park in early 2000s. So 2004, 2005, 2006 with seminal papers showing that cancer agent is very likely to be also an anti-aging compound, and I now believe that this compound should be tried in multiple age associated pathologies and also for immmunosenescence, versing immunosenescence.

But other geroprotectors, promising geroprotectors, like metformin, can be very well combined with rapamycin, NAD boosters like nicotinamide riboside, nicotinamide mononucleotide may be tried in clinical trials. Senolytic, these could be tried also after COVID because of the fibrotic build-up, fibrosis in the lungs and also as rehabilitation after COVID. I think that some other promising geroprotectors including [inaudible] B3 activation. Again, that’s much less explored, could lead to gene clocks. So since 2013 there has been a revolution in gene clocks starting from our Panam and Horvath work showing that methylation data is very predictive of chronological age.

There are very highly accurate markers of aging but there are many others, so like lab tests, very simple clinical blood tests can be used to predict chronological age and my group published the first ones using deep learning. And there are many others including microbiomics aging clock, including imaging aging clocks, including transcriptomic aging clocks, and proteomics aging clocks, and whatever data there is longitudinal data that could be used to construct clocks should be collected during the clinical trials. And we should look at whether some of the molecules are making you younger or older compared to the chronological age from the various data types and look at the effects.

So that’s the current proposal on the paper, so I’m calling to try geroprotectors to protect the elderly, to potentiate their immune response to COVID, and also to try the aging clocks for both clinical trials enrollment and for monitoring to see what molecules are making you younger or older on pretty much every level. I’m also calling for those clinical trials because after COVID-19, after the epidemic is over, we’re going to have major economic consequences. There’s a lot of people who have been out of work, there’s been substantial capital influx from pretty much every government into the economy, so quantitative easing that might lead to inflation. We don’t know what’s going to happen to the economies of developed countries.

Previously, I published several papers and a book on economics of aging showing that increases in productive longevity would lead to substantial economic growth. If we manage to reduce the amount of money being spent on healthcare in the elderly by preventing disease and by rejuvenating the elderly, making them more resilient to disease, just that leads to unprecedented economic growth. And of course, if we make them more productive and contributing to the labor force longer, we will see unprecedented economic growth even further.

So we’re talking about double digit growth in developed countries. So here we can kill many birds with one stone, so to speak, even though I don’t like the word “kill.” And if we can try geroprotectors to prevent disease, but at the same time we can boost the economy after the epidemic is over if some of those geroprotectors show efficacy and people start believing more that aging is plastic and we can push the envelope in that area and really rejuvenate the elderly.

So that’s the paper and thank you very much for watching this. Stay healthy.

Click here to read the full study published in Aging.

Aging is an open-access journal that publishes research papers monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact media@impactjournals.com.

Aging is a proud participant in the AACR Annual Meeting 2021 #AACR21
Aging is a proud participant in the AACR Annual Meeting 2021 #AACR21

Behind the Study: An Ethical Mouse Model to Assess Lifespan

Researchers discuss their 2019 study published by Aging, entitled, “Conclusions from a behavioral aging study on male and female F2 hybrid mice on age-related behavior, buoyancy in water-based tests, and an ethical method to assess lifespan.”

Behind the Study is a series of transcribed videos from researchers elaborating on their recent oncology-focused studies published in Aging. A new Behind the Study is released each Monday. Visit the Aging YouTube channel for more insights from outstanding authors.

Malin Hernebring

Okay. So we met the first time at the Cold Spring Harbor Meeting on Mechanisms of Aging. And me and Julia went there with a lot of data and, if I remember correctly, we just realized that our aging study is so good that we can publish the wild-types only.

Julia Adelöf

I think we realize that it had never been done in hybrid mice in both females and males. So just that we had hybrid mice, but also included both sex, made this study completely new, by just using wild-type mice.

Malin Hernebring

And we were so happy to meet you there, Jamie, and we had a nice discussion over our results and decided to take you on as a collaborator, which we’re very happy about.

Jamie Ross

Me as well, that was really fantastic, that was fun. I got to learn a lot about hybrid mice, which I had really had never thought about using before, to be perfectly honest. And especially learning about the body composition, which we’re going to talk more about. It was really a fun experience. So thank you. Both of you.

Julia Adelöf

Our pleasure.

Malin Hernebring

So you mentioned Julia, is that another aspect is that we include both sex. We talked about this a little bit before, how the research has changed, so that it has been so very focused on male mice. And now starting to realize the importance of including females in the study, especially since, I mean, women are many of the people that are taking the drugs that are developed.

Julia Adelöf

You see very real test, indeed. I think a lot of things has changed in the past, since we started the study, and nowadays there have been a lot of incentives to include both sex, which is a great thing. Our problem is though that, if you think about it, the tests that we use are predominantly, have been done with male mice for a long time. And that includes behavioral tests. So what was really important with our study, is that we follow these mice, both behaviorally, but also physiologically. And I’m going to come into the mobility test. To address depressive-like behavior, we used a common test called the forced swim test. And in this test, mice are placed in a water tank and then you record how they move in the water.

And both Malin and I had been taking… Were joining swimming teams at the time. And then you really get this feeling for that, people have different floating capacities or they act differently in water. And since we had the physiological data from these mice, we could see that the females had 50%, at the highest, more fat mass than the male mice. And as well, because we were swimming and thinking about this thing…

Malin Hernebring

…If I can just interrupt, because you were saying how, when you were crawling that you had to really have good speed and use your legs a lot to keep floating. While me having, maybe a bit more floating material, did not have that problem at all. So this is really positive of how we came this conclusion. And just thinking about crawling and how you line the water, whereas you’re floating.

Figure 1. Survival of C57BL/6N×BALB/c F2 hybrid male and female mice presented as intervals of natural lifespan.

Julia Adelöf

And I think one of the greatest things with our studies, that we actually included, the body composition when we were doing the data. And commonly it’s only the body weight, the differs, and we did not see a difference in the body weight. We saw that females and males weighed the same, but they had differences in lean mass and in fat mass. And then when we were looking at this a little bit more in detail, we actually saw that, how much the mice swam in water correlated, to how much percentage fat mass they had.

And this is also has never been shown before. I haven’t found a study where they actually address body composition and floating capacity. And since water tests are used for several different behavioral phenotypes, it’s very important in this study as well, that when you do water tests, that you actually take into account, differences in body weight. If you’re looking at obesity models, and as in our case, we found that there was a sex difference in water, but this sex difference could directly account for, by looking at the difference in the fat mass. So we cannot say, but there’s a strong correlation between immobility or activity in water and body composition.

Malin Hernebring

So we found that 46% in the younger mice, 46% of the difference was caused directly by the [inaudible] it’s…

And I mean, that’s a lot.

Jamie Ross

When you think about it that it really is a lot, because there’s a lot of behavior tests as Julia was mentioning. There’s more to water maze, which people classically use, which of course involves water and the ability to float. And how much muscle mass, how much fat mass you have, really directly can affect your ability to perform that task. Also, the radial arm maze can be filled with water as well. And these are all commonly used cognitive tests, that researchers use. And, again, I’ve never seen it published anywhere, where people are really thinking about how there are sex differences besides, sort of the place cells and how you use your environment. People usually focus on that aspect of the test, not the actual physical aspects.

Julia Adelöf

And I think that’s a challenge that we will see more of, now that both sexes are included in the studies. Because we are so focused on measuring one thing, which is depressive-like behavior in this case. And we don’t think about, “okay, so what are the other sex differences?” Because where you found a difference, and that’s super interesting, but can that actually be explained by something, like in this case, physiological. And that’s why data can be very misinterpreted, if we don’t know what kind of confounding effects, due to other sex effects that is involved in, or is interfering with our results. So I think it will be interesting to see, and I think that our study was early, because we included Themis mice early. But I think this kind of sex-different perspective and the secondary effects, will be even more common in the literature from now on.

Malin Hernebring

I would think so too, and hopefully also… I mean, one of the reasons that we’re doing this now, is to spread this information, so that people will know that there is this correlation. But I’d like to go through a bit, about this reduced exploratory behavior as a conserved hallmark. So one aspect of this study is that, because we are euthanizing animals that are suffering from severe disease, we are looking specifically at aging and not features that come along with decease. So I think this makes our results stronger also, and the fact that what we do see is a reduction in exploratory behavior, while we don’t see any effect on memory, for example, which we were surprised to see.

Interestingly, we neither see an effect in bone density with aging. I mean the old cohort that we’re using, they are not… So they’re at a stage where it’s about 70% survival. So they started to die, but they’re still, relatively healthy. And this was by choice that we chose this, because we didn’t want to have a selection on the cohort, that we looked at. We didn’t want to study the ones that were extremely long-lived only, we wanted to know more about the whole population.

Julia Adelöf

I think it can explain it also, because it’s a difference between aging mice and dying mice.

Jamie Ross

The lifespan and the new way to try to approach it, I think, that’s a really good point. You put an animal in an open field, and an aged animal, and if they have these other comorbidities, you’re not sure if they are moving less, because they actually are moving less. They have sarcopenia and these other issues, or maybe they have some arthritis, or they’re moving less because, wow, they’re actually in pain, because they have a disease.

Julia Adelöf

And that’s a challenge in the aging field, because you want to do research on old mice. But how do you do the discrepancy between dying mice and old mice? And I think one of the reasons why we actually, that we used in our protocol as well. Is that we removed animals with diseases, also helped us forming a cohorts of aging mice and not dying mice.

Figure 2. Physiological parameters of mice in the cohorts for behavioral assessment.

Malin Hernebring

So basically this method is about giving an estimate of the so-called life span. I mean, traditionally life span experiments are conducted until the animals are… Or they are allowed to live, for as long… That they are considered so sick from disease so that they are not likely to survive for another week and that means that they could go for months or even years with big tumors. Ethically, that’s very problematic, but as we were talking about, it’s also can complicate other analysis of course. But the way that we do this then is that, when we euthanize these animals, we make two curves.

One curve, we count these animals as if they had died from natural causes, and that’s, of course, is an underestimation. And then we make another curve that we calculate these animals as if they were as healthy as their litter mates, which they were not, because they had a terminal illness. So then that’s an overestimation of the life span, so then we have an interval that will be the min and max of this life span. We think this is a really good method, that we hope people will start using, in life span analysis.

Jamie Ross

I think it’s really fantastic, actually. The more and more I think about it, I know that maybe I’m biased. But so many institutions are not allowing researchers, for obvious reasons, to perform life span studies any more because they do not want the animals, understandably so, to be in pain and to be sick. So this is actually a really nice way to say, “Hey, I’m doing a life span analysis, however, I’m going to euthanize the animals who are sick and still get good, solid data that I can use.”

Julia Adelöf

And compared to other aging studies, because that was one of our issues that, we wanted to euthanize our animals upon early signs of disease. But since no other aging studies, that we found had euthanized the same amount or the large percentage of mice, we knew that it will be different because of course they will have a longer life span. But since we created the this, we could actually compare our data with it, even though we use the different protocol, with a lot of other aging studies in the fields, which is also important to know the platform, and to also compare your research against what’s known in the literature.

Malin Hernebring

And to be able to define the age status of your cohorts you’re looking at. I mean, yeah. And this was initially in the paper that we submitted, I don’t remember where now, but it was part of the review… it’s comments, that the animals are probably not feeling so well, because they have such a short life span. And that’s when we started to think about this and to invent this method, basically.

Jamie Ross

Are we going to go back and talk about the exploratory behavior a little bit more? Because one point that I wanted to also mention was, I think that this is a really nice, easy way to monitor what’s going on with the animals because there’s no cognitive testing involved, in the sense that, you don’t have to worry, “Oh, I’m using males or females so I shouldn’t use this for the females, I shouldn’t use this test for the males.” It’s a conserved test, that you can use for both males and females. It’s easy in the sense that it requires, not an absurd amount of equipment. And you put the animals there and then you walk away, and you let them stay in that environment for an hour, hour and a half, and then you look at the first 10, 15 minutes of that exploratory time. And I think that is also something really nice that people … I hope other researchers see and think how they could incorporate that measurement into their aging analysis of the animals.

Julia Adelöf

Yes and that it’s easy to do opens up for a lot of people to do it. But I think also one of the findings of this paper was that we found exploratory behavior to decrease, that we didn’t find learning and memory. And when you look at a lot of behavioral testing, they have an exploratory or exploration component in their tests. And since we found, they could show that, in a hybrid background, in both females and males, this declines. My question, is exploratory behavior and the decline an exploratory behavior, are confounding effects of other results, that has been shown of learning and memory? Because they are based on exploratory components as well. So I think, also when you perform aging studies, you should actually assess the exploratory behavior, to be able to know what your other behavioral tests show, since we have these components integrated into the test.

Jamie Ross

That’s a very good point. We always try to do a light-dark test and some sort of transition test to make sure that they are perceiving their environment correctly and that they move correctly, as well as the open field and other things. So, yeah, I think that’s a really good point to make, that I hope other researchers, who want to study aging more and other age-related diseases, think about.

Julia Adelöf

And also to be cautious about when you do a behavioral test and you have a test battery, is preferable, if you do the open-field tests early on, because you can also see a change. If you do open field test, we learned our lesson. If you do it later, you can actually change the order. So you want to have it early on, in the behavioral test battery. And then you would know also, if you find differences and you need to exclude results from following analyses and tests.

Malin Hernebring

And also that the animals are affected by being handled, so their exploratory behavior will change. We know now it’s hard to compare them.

I had another comment on this…this DXA equipment may not be standard in all laboratories.

Julia Adelöf

For body composition, the DXA. I don’t think everyone knows, the DXA is used for measuring the body composition of mice and rodents in this different type.

Malin Hernebring

Exactly. I don’t know, maybe someone has done this, but I’m just thinking that one way, instead to do this, would be to analyze the density of the mouse. I mean, basically just putting them in water and see how much volume that goes out. And then that would be some kind of measure of what the mouse density is. I’m hoping they’re not taking up.

Julia Adelöf

Mice float, they’re known to float and they don’t do this themselves, but if they’re not naked mice, they do float. And I was thinking, yeah, I think it would be an excellent follow-up to actually look at. And I think it has been done at positioning, so I know that it’s a paper out where they have tried to remove the [inaudible], so they added detergent into the water and then they could see that the position of the mice changed. So it has been shown that the…

Malin Hernebring

…The buoyancy.

Julia Adelöf

…Yeah, but that has not been done in in behavioral tests. So you can see that they do change their position and their angle in the water, but they haven’t correlated this to anything.

Malin Hernebring

Okay. So the take home messages from this work are that we want you all to know that the main conserved hallmark of aging behaviorally, is a decreased exploratory behavior. And we want you to be aware when you’re doing water-based tests to… as a body composition because fat mass can correlate to behavior in water-based tests. And also we want everyone using or doing a lifespan analysis, to think about the ethics surrounding the lifespan analysis and also be aware that there is a method to calculate lifespan, in which animals that suffer from severe disease or from pain, can be euthanized and still give valuable data. I’d like to thank the Swedish Foundation for Strategic Research, SSF for funding Julia’s PhD and also Jamie Ross and contributors to you. I think that’s all we had, right?

Julia Adelöf

Thank you for listening.

Malin Hernebring

Thank you for listening.

Jamie Ross

Thank you.

Click here to read the full study published in Aging.

Aging is an open-access journal that publishes research papers monthly in all fields of aging research and other topics. These papers are available to read at no cost to readers on Aging-us.com. Open-access journals offer information that has the potential to benefit our societies from the inside out and may be shared with friends, neighbors, colleagues, and other researchers, far and wide.

For media inquiries, please contact media@impactjournals.com.

Aging is a proud participant in the AACR Annual Meeting 2021 #AACR21
Aging is a proud participant in the AACR Annual Meeting 2021 #AACR21

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