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Trending With Impact: When Aging Switches On Alzheimer’s

By Kathryn Atkins June 24, 2021 June 25, 2021 Misha Blagosklonny

In a trending Aging editorial paper, researchers explain that switches in the aging process may be a window of opportunity for patients with Alzheimer’s disease and potential epigenetic treatments.

Figure 1. The EORS downward spiral of aging and Alzheimer’s (Epigenetic Oxidative Redox Shift) [2].

The Trending with Impact series highlights Aging publications that attract higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news about the latest trending publications here, and at Aging-US.com.

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Alzheimer’s disease (AD) develops at different times for different people due to known and unknown variables. AD and aging share a number of features in common, such as oxidative stress, mitochondrial impairment, and bioenergetic and metabolic shifts. Aging is an unmistakable risk factor for Alzheimer’s disease, but what causes aging to switch it on? Do these “switches” present opportunities for intervention?

In 2021, researchers from the University of California and the University of South Carolina wrote an editorial article about the onset of AD—propagated by switches that take place during the aging process. Their trending paper, published in Aging’s Volume 13, Issue 10, was entitled: “When aging switches on Alzheimer’s.”

“[…] the complex mechanisms of switching on so many AD pathologies remain underexplored.”

Oxidative Shifts

“Age-related redox stress, often measured as oxidative stress in aging and AD launches a global switch in the epigenetic landscape, widely affecting methylation, histone modification, and noncoding RNA regulation [5], to further drive downstream metabolic and energetic shifts.”

The authors begin this editorial paper by prefacing readers with the epigenetic oxidative redox shift theory of aging. They explain that the sedentary lifestyle often accompanied by old age resets epigenetic marks to prepare for low mitochondrial capacity and minimal energy production. In order to maintain this setting (resting redox energy levels), the body switches to require more oxygen and energy when performing physical activities and increases the conversion of glucose to lactose (the Warburg Effect). In turn, these metabolic shifts (now enforced by the epigenome) reinforce sedentary behavior—forming a vicious cycle.

“Our environment, lifestyle, stress, physical activity, and habits all modulate epigenetic control of gene expression for continuous environmental tracking.”

Conclusion

Oxidative shifts alter the activity of numerous redox-sensitive transcription factors, enzymes, and signaling proteins. The researchers explain that these oxidative switches taking place in patients with Alzheimer’s disease are potential targets for epigenetic treatments.

“While studies on these ‘switches’ enable elucidation of the underlying mechanisms for when aging switches on Alzheimer’s degeneration, more importantly, these ‘switches’ of redox, epigenetics and neuroinflammation encourage early interventions to decelerate AD pathology and retain functional memory.”

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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Trending with Impact: Aging and Lung Function Decline

By Kathryn Atkins June 10, 2021 June 11, 2021 Misha Blagosklonny

Is there an association between biomarkers of aging and lung function? Researchers conducted a study which aimed to find out.

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By 2050, the United States Census Bureau estimates that 83.7 million people aged 65 years and older will be living in the U.S.—a number that will nearly double the 2012 estimated population. As the scale of the elderly population magnifies, additional aging research will continue to be increasingly relevant.

“According to the American Lung Association, the lung matures by age 20-25 years, and its function declines gradually after the age of 35 [30].”

Among the elderly population, lung function has been found to vary, even between those who have never smoked, are the same height, and of the same chronological age. This has led researchers to wonder if lung function decline is part of the underlying biological aging processes. No published studies had investigated the associations between epigenetic aging biomarkers and lung function, until 2020.

In 2020, a team of researchers—from Harvard T.H. Chan School of Public Health, Icahn School of Medicine at Mount Sinai, Northwestern University Feinberg School of Medicine, VA Boston Healthcare System, Boston University School of Medicine, and Columbia University—aimed to begin answering this question. The researchers conducted a study with participants from the longitudinal Normative Aging Study (1963 – present) to determine whether or not there is an association between seven biomarkers of aging (BoA) and three measures of lung function. Their paper was published by Aging and entitled: “Biomarkers of aging and lung function in the normative aging study.”

“In this present study, we hypothesized that some of these BoA are associated with lower lung function.”

The Study

From 1961 to 1970, healthy U.S. males between the ages of 21 and 81 enrolled in the ongoing Veterans Affairs Normative Aging Study. One of the objectives of the study is to characterize the biomedical and psychosocial parameters of normal aging (distinct from the development of disease). There are a total of 2,280 participants in the Normative Aging Study (NAS). In the current Aging study, researchers included 696 elderly men from the NAS.

“The present study included 696 elderly men with 1,070 visits during years of 1999-2013.”

In search of associations between biomarkers of aging and lung function, the researchers first collected the study participants’ personal characteristics, including age, smoking history, height, weight, BMI, education, blood work, and other measures. They then analyzed lung function using three tests: forced expiratory volume in one second (FEV1), forced expiratory volume in one second / forced vital capacity (FEV1/FVC), and maximum mid-expiratory flow (MMEF).

Next, the team analyzed the participants’ epigenetic biomarkers of age; including GrimAgeAccel, PhenoAgeAccel, intrinsic epigenetic age acceleration (IEAA), extrinsic epigenetic age acceleration (EEAA), and Zhang’s DNAmRiskScore; as well as non-epigenetic biomarkers of age, including telomere length and mitochondrial DNA copy number (mtDNA-CN). They then assessed for associations between these biomarkers and the three measures of lung function.

Conclusion

“In this longitudinal cohort of 696 elderly males, we found that GrimAgeAccel and Zhang’s DNAmRiskScore were associated with lower lung function, including FEV1, FEV1/FVC, and MMEF.”

The researchers found that the GrimAgeAccel and Zhang’s DNAmRiskScore were both associated with lower lung function in all three measures of lung function. They found no correlation between non-epigenetic aging biomarkers and lung function, but the researchers mention several limitations of their study. Their results suggest that epigenomic variation could help illuminate the pathogenesis of the reduced lung function that comes with age.

“Epigenetic mechanisms such as DNAm may provide further explanation for decreases in lung function as individual age.”

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

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TRENDING WITH IMPACT: EFFECTS OF EXERCISE ON AGING

By Kathryn Atkins May 27, 2021 May 28, 2021 Misha Blagosklonny

Researchers surveyed available literature related to exercise and its association with longevity and aging. This extensive review expands on exercise as a lifestyle intervention and its ability to counteract cellular and tissue aging.

Figure 4. Conceptual overview. Created in BioRender.

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Regular physical exercise provides benefits for both the body and mind, but how exactly does this healthy habit benefit our cells, signaling pathways, organs, and even bones? Furthermore, how can we employ regular exercise as part of an anti-aging strategy to extend our healthspan and lifespan?

Two researchers from the Beta Cell Aging Lab at Harvard Medical School authored a recent review paper which breaks down the currently available research on this very topic, with a special focus on pancreatic beta-cells and Type 2 diabetes. The authors detailed the recorded effects of exercise at systemic and cellular levels, its effects on each of the hallmarks of aging, and a potential molecular regulatory node that may integrate those effects. This review was published in May of 2021 by Aging, and entitled: “Effects of exercise on cellular and tissue aging.”

THE NINE HALLMARKS OF AGING

With age, cellular functions and systems in the human body progressively decline and destabilize, which eventually leads to disease and all-cause mortality. There are nine hallmarks of aging, which are classified as either primary, secondary, or integrative: genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient-sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered intercellular communication.

“Exercise is a promising lifestyle intervention that has shown antiaging effects by extending lifespan and healthspan through decreasing the nine hallmarks of aging and age-associated inflammation.”

The researchers in this review explain that exercise is capable of counteracting each of these hallmarks of aging at systematic and cellular levels. They used publicly available research to cite and discuss the effects of exercise in each hallmark of aging in clear and thorough detail. The purpose of this article is to summarize this review, though readers are highly encouraged to read the full paper for deeper insights.

“The literature was surveyed on MEDLINE through freely accessible PubMed as a search engine for the terms: ‘exercise’, ‘longevity’ and ‘aging’; the most relevant studies were included as they related to the 9 hallmarks of aging.”

AMPK AS A CENTRAL REGULATOR

“In summary, exercise attenuates all hallmarks of aging through different molecular pathways and effectors that seem independent and disconnected.”

Given that exercise regulates each of these hallmarks individually, the researchers hypothesize that there must exist some kind of molecular regulatory node(s) capable of coordinating these responses. They propose that the 5’ adenosine monophosphate-activated protein kinase (AMPK) enzyme/protein could play this role.

“In summary, AMPK activation through exercise can impact all the hallmarks of aging through different signaling pathways as summarized in Figure 2 and can act as a signaling node capable of orchestrating many of the effects of exercise on the health span of different tissues and organs.”

EXERCISE AND TYPE 2 DIABETES

The researchers also discuss the effects of exercise on Type 2 diabetes mellitus (T2D).

“In summary, exercise activates molecular signals that can bypass defects in insulin signaling in skeletal muscle and increase skeletal muscle mitochondria, which are associated with improved insulin sensitivity in skeletal muscle and therefore improve aging-associated effects of T2D.”

Figure 1. Effects of exercise upon the aging process of different organs and systems. Created in BioRender. — **Figure 1.** **Effects of exercise upon the aging process of different organs and systems.** Created in BioRender.

CONCLUSION

“We propose that future studies should address the effects of exercise on tissues which are not considered its direct targets but do show accelerated aging in T2D, such as pancreatic β-cells. In these, the role of AMPK and its physiological control will become especially significant as exercise is considered a cellular antiaging strategy.”

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

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Trending with Impact: Method Yields Cell-Type-Specific Brain Data

By Kathryn Atkins May 13, 2021 May 14, 2021 Misha Blagosklonny

Researchers used a bioinformatics approach (ESHRD) that leverages gene expression data from brain tissue to derive cell-type specific alterations in Alzheimer’s disease.

Neurons cells from the brain under the microscope.

The Trending with Impact series highlights Aging publications attracting higher visibility among readers around the world online, in the news, and on social media—beyond normal readership levels. Look for future science news about the latest trending publications here, and at Aging-US.com.

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Cell-to-cell variability in the human brain is significantly heterogeneous. An abundance of differential brain cell types makes it laborious and expensive for researchers to generate single-cell gene expression data. While some studies use laser capture microdissection (LCM) and single-cell RNA sequencing (scRNA-Seq) to directly address the cellular heterogeneity in brain tissue, due to labor and cost, these studies generally have a small sample size and face power concerns. Most gene expression profiling studies of patients with Alzheimer’s disease (AD) are conducted post-mortem using brain tissue homogenates.

“Ultimately, the overall goal of gene expression profiling in AD is to understand the transcriptome changes in all major cell types of the brain in a well-powered approach that would facilitate the exploration of all the variables mentioned above.”

The need existed for a cost-effective bioinformatics approach to leverage expression profiling data from brain homogenate tissue to derive cell type-specific differential expression and pathway analysis results. In 2020, researchers from Columbia University Medical Center, The University of Sydney School of Medicine, University of Miami, and the Banner Sun Health Research Institute described an Enrichment Score Homogenate RNA Deconvolution (ESHRD) method for identifying alterations in the brain. They published a research paper in Aging’s Volume 12, Issue 5, entitled: “ESHRD: deconvolution of brain homogenate RNA expression data to identify cell-type-specific alterations in Alzheimer’s disease.”

The Study

“We applied our approach to different gene expression datasets derived from brain homogenate profiling from AD patients and Non-Demented controls (ND) from 7 different brain regions.”

Researchers conducted brain region cell-specific pathway analysis and Gene Set Enrichment Analysis (GSEA). The team mapped and measured five different cell types in seven different brain regions. The cell types included: microglia, neuron, endothelial, astrocyte, and oligodendrocyte. Endothelial and oligodendrocyte are two cell types that are not easily examined in the brain and only very little gene expression data previously existed for Alzheimer’s disease.

“We conducted RNA expression profiling from both brain homogenates and oligodendrocytes obtained by LCM from the same donor brains and then calculated differential expression.”

The researchers used a dataset of Multiple System Atrophy (MSA) patients (n = 4) and controls (n = 5) to validate their ESHRD method. Homogenate, LCM, and scRNA-Seq results were compared using the ESHRD method. They also compared their findings to other research studies.

Results

“The ESHRD approach replicates previously published findings in neurons from AD patient brain specimens, and we extended our work to characterize novel AD-related changes in relatively unexplored cell types in AD, oligodendrocytes and endothelial cells.”

Neuronal, endothelial cells, and microglia were found to be the most represented “cell-specific” gene classes in patient brains with Alzheimer’s disease. Neuronal-specific genes were downregulated and enriched for synaptic processes. Endothelial genes were found to be upregulated in AD and enriched for angiogenesis and vascular functional processes.

“Differentially Expressed Genes (DEGs) we labeled as “mixed” represent the most prevalent class (73.4%), followed by DEGs labeled as microglia (6.6%), neuron (5.9%) and endothelial (5.7%). Astrocyte and oligodendrocyte labeled DEGs have a frequency of 3.6% and 3.1%, respectively.”

Microglia showed different patterns of expression across the brain in multiple regions. They found that astrocyte genes were enriched in SLC transport and immune processes and oligodendrocytes were enriched for the Glycoprotein metabolism in Alzheimer’s disease.

Conclusion

“We demonstrate the ability of this approach to highlight known neuronal-specific changes in the AD brain and utilize it to identify novel changes in endothelial cells and oligodendrocytes, two cell types not easily examined in the brain and for which only minimal gene expression knowledge exists in AD.”

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

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Trending with Impact: Epigenetic Age Decreased in Diet & Lifestyle Study

By Kathryn Atkins April 29, 2021 May 27, 2021 Uncategorized

Researchers conducted an eight-week study on diet and lifestyle among a small cohort of 43 male participants between the ages of 50 and 72.

Happy senior couple buying fresh food at the market

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In addition to the well-known personal and social costs of aging, the economic costs of aging are also considerably high. Research finds that investing in delaying aging is much more cost-effective than disease-specific spending. A study found that if Americans as a whole delayed their aging by 2.2 years (while extending healthspan), economic savings over 50 years could amount to a cumulative $7 trillion.

“The growing health-related economic and social challenges of our rapidly aging population are well recognized and affect individuals, their families, health systems and economies.”

Across three countries (the United States, Canada, and Israel), researchers from the Institute for Functional Medici n e, American Nutrition Association, National University of Natural Medicine, Ariel University, McGill University, and the University of California, conducted a new pilot study on the effects that diet and lifestyle intervention have on aging among healthy males between the ages of 50 and 72. This research paper was published in Aging’s Volume 13, Issue 7, and entitled, “Potential reversal of epigenetic age using a diet and lifestyle intervention: a pilot randomized clinical trial.”

The Study

The researchers organized a cohort of 43 healthy adult males between the ages of 50 and 72. Half of the participants (n=21) completed an eight-week treatment program, and the other half (control group=22) received no intervention. Interventions within the treatment program included regimented diet, sleep, exercise, relaxation guidance, and supplemental probiotics and phytonutrients. Prior to the treatment program, participants were enrolled in a preliminary education week to become acquainted with the researchers’ prescribed dietary and lifestyle interventions.

“To our knowledge, this is the first randomized controlled study to suggest that specific diet and lifestyle interventions may reverse Horvath DNAmAge (2013) epigenetic aging in healthy adult males.”

Diet Prescription

Researchers prescribed the participants with mostly (not entirely) plant-based diet instructions to consume measured portions of liver, eggs, dark leafy greens, cruciferous vegetables, colorful vegetables (excluding white potatoes and sweetcorn), beets, pumpkin seeds (or pumpkin seed butter), sunflower seeds (or sunflower seed butter), methylation adaptogens, berries, rosemary, turmeric, garlic, green tea, oolong tea, animal protein, and low glycemic fruit. They were prescribed two daily doses of PhytoGanix®, which is a combination of organic vegetables, fruits, seeds, herbs, plant enzymes, prebiotics, and probiotics. A daily two-capsule dose of UltraFlora® Intensive Care, containing Lactobacillus plantarum, was also prescribed.

General guidance included that participants should choose organic food products over conventional, and to consume “healthy” oils and balanced types of fat, including coconut, olive, flaxseed, and pumpkin seed oil. Participants were told to avoid consuming added sugar, candy, dairy, grains, legumes/beans, and to minimize using plastic food containers. In addition, the prescription instructed participants to stay hydrated and not to eat between 7pm and 7am.

Lifestyle Prescription

The participant exercise prescription was a minimum of 30 minutes per day for at least five days per week, at 60-80% intensity. They completed two 20 minute breathing exercises daily, using the Steps to Elicit the Relaxation Response process developed by Herbert Benson, MD. Participants were prescribed to sleep a minimum of seven hours per night.

Measuring Epigenetic Age

“Currently, the best biochemical markers of an individual’s age are all based on patterns of methylation [5].”

To extract DNA from the participants, researchers collected saliva samples and evaluated their RNA and DNA. They used methylation kits, assays, and the Horvath DNAmAge clock to conduct genome-wide DNA methylation analysis and calculate epigenetic age (DNAmAge) at the beginning of the study, and at the end.

“Horvath’s DNAmAge clock predicts all-cause mortality and multiple morbidities better than chronological age. Methylation clocks (including DNAmAge) are based on systematic methylation changes with age.”

Conclusion

According to the Horvath DNAmAge clock, participants in the treatment group scored an average 3.23 years younger at the end of the eight-week program when compared to participants in the control group. While these findings are meaningful, additional studies with a larger cohort size, longer duration, and other human populations will be needed in order to confirm these results.

“Notably, the shorter timeframe of this study and the scale of potential reduction, while modest in magnitude, may correlate with meaningful socioeconomic benefits, and appears to have the potential to be broadly achievable.”

Click here to read the full study, published on Aging-US.com.

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