DNA methylation

Is liver damage reversible?

gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Stress , , ,

This 2021 rodent study measured sequential liver changes caused by a high-fat diet:

“Using a longitudinal mouse study of diet-induced obesity in male mice, we investigated kinetics of hepatic DNA methylation and gene expression compared to those of obesity-induction to assess if they could be causal for development of insulin resistance. We aimed to find out if these changes were reversed by massive weight loss induced by vertical sleeve gastrectomy or metformin treatment.

We identified two CpG sites within exon 1 of Fgf21 that became gradually hypomethylated upon HFD feeding. DNA demethylation started between week two and four, to become significant at week five, and significantly correlated with hepatic Fgf21 gene expression.

These DNA methylation changes preceded development of insulin resistance, and were potentially causally involved in increased Fgf21 expression and plasma levels associated with insulin resistance. This points to a key regulatory function of gene body DNA methylation, which was eventually a compensatory response to counteract the developing insulin resistance.

HFD-induced decrease in Fgf21 DNA methylation could not be reversed by vertical sleeve gastrectomy or metformin treatment. As soon as weight loss slowed down or mice started to re-gain weight, differences in DNA methylation were no longer detected compared to sham-operated mice.

1-s2.0-S0955286321003272-ga1_lrg

As the altered DNA methylation pattern was acquired during adulthood in differentiated cells, our data emphasize that metabolic programming via DNA methylation is dynamic and not restricted to fetal development. This supports the concept that individuals can actively influence their DNA methylation patterns by lifestyle choices.

Our data indicate that DNA methylation alterations in key metabolic tissues can be acquired by an obesogenic diet, and not easily be reversed by interventions common in obese and diabetic subjects.”

https://www.sciencedirect.com/science/article/pii/S0955286321003272 “Dietary induction and reversal of obesity and insulin resistance is associated with changes in Fgf21 DNA methylation in liver of mice”

This study attempted two interventions that didn’t have desired effects. All about the betaine mentioned others that may reverse liver epigenetic changes.

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Human agency vs. brain dysfunction

gettingwell4 2-3 stars Required further work, Cerebrum, Epigenetics, Immune system, Limbic system, Lower brain, Memory, Stress, Thalamus , , , , ,

This 2021 human study used epigenetic clock technology to assess chronic inflammation as a driver of cognitive decline through its effects on brain structure:

“An epigenetic measure of C-reactive protein (DNAm CRP) was assembled for each participant. We found that higher inflammatory burden, indexed by DNAm CRP scores, associated with poor cognitive and neuroimaging brain health outcomes.

inflammation vs cognitive ability

DNAm CRP exhibited significantly larger associations with brain structural MRI metrics (including global grey and white matter atrophy, poorer white matter microstructure, and increased white matter hyperintensity burden) than serum CRP. Given that the 7 CpGs which make up DNAm CRP score reside in inflammation and vascular-related genes, these DNAm CRP-brain MRI associations may be capturing the impact of upstream inflammatory activity above and beyond that of serum CRP levels.

Our results indicate that some cognitive domains (processing speed) may be more mediated by brain structural consequences of chronic inflammation than others (verbal memory, visuospatial ability).

Our results add to the evidence base that DNAm-based predictors of inflammation may act as a quantifiable archive of longitudinal effects of these exposures – and other unaccounted for health and genetic profiles – that serum CRP levels fail to capture. By utilising an epigenetic inflammation measure, which integrates information from multiple immune-related CpG sites, we may provide a more reliable measure of chronic inflammation and thus a more comprehensive overview of consequences of chronic inflammation on brain structure and function.”

https://n.neurology.org/content/early/2021/11/17/WNL.0000000000012997.long “DNA Methylation and Protein Markers of Chronic Inflammation and Their Associations With Brain and Cognitive Aging”

These researchers essentially negated many of their findings by acknowledging:

“Although we endeavoured to remove participants with cognition-related pathology, these were screened via self-reported diagnoses, and we may be missing undiagnosed or subclinical incident neurodegenerative pathology.”

It wasn’t sufficient to claim in the Abstract section “Participants (N = 521) were cognitively normal, around 73 years of age” then include in the Discussion section a one-sentence limitation of relying on self-reports. Everyone defends themself against current and past realities and experiences.

Hard to imagine that objective measures such as the three comprising cognitive ability weren’t better screens. But then too many 73-year-old subjects may not have been “cognitively normal” and this study wouldn’t be adequately powered?

Can humans counteract inflammation? Non-communicable diseases? Smoking? Immune system degradation? Yes. No personal-agency actions were mentioned.

Also note this study’s social norming. The above-pictured 30-year-old female was busy at work, and subsequently hoisted a cat instead of a child in later years.

Take responsibility for your own one precious life.

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Epigenetic clocks vs. individual choices

gettingwell4 2-3 stars Required further work, Epigenetics, Immune system , ,

This 2021 human twin study used four epigenetic clocks:

“We examined the mediating role of lifestyle factors on the association between sex and biological aging in younger and older adults. The Finnish Twin Cohort (FTC) includes three large cohort studies:

  1. The older FTC includes twins born before 1958;
  2. Finntwin16 includes twins born in 1975-1979; and
  3. Finntwin12 includes twins born in 1983-1987.

In comparison to women, men were biologically older and, in general, they had unhealthier life habits. The effect of sex on biological aging was partly mediated by body mass index and, in older twins, by smoking. Sex was directly associated with biological aging, and the association was stronger in older twins.

over 50 twins

Declining smoking prevalence among men is a plausible explanation for narrowing of the difference in life expectancy between sexes. Data generated by epigenetic clocks may help in estimating effects of lifestyle and environmental factors on aging and in predicting aging in future generations.”

https://academic.oup.com/biomedgerontology/advance-article/doi/10.1093/gerona/glab337/6424421 “Do epigenetic clocks provide explanations for sex differences in lifespan? A cross-sectional twin study”

It was too much to ask of epigenetic clocks to ferret out preclinical symptoms of lifestyles and environments accelerating aging in younger twins. Levine’s Phenotypic Age clinical measurements could assess accelerated aging trajectories, but may not have been available for this study. People who are busy abusing their bodies into non-communicable diseases have plenty of other warning signs, like abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum high-density lipoprotein.

Preclinical symptoms may be reversible by individual choices that influence lifestyle and/or environment. Effective healthspan and lifespan changes measurable by epigenetic clocks are usually limited once clinical symptoms emerge, though.

Consider this rodent study’s graphic from Part 2 of Eat broccoli sprouts for your eyes:

retina function

This chart demonstrated that preventing diabetes’ negative effects on retinal function (i.e. controls) was measurably better than trying to fix subjects’ vision after onset of diabetes.

I would have liked this study to address a morbidity phase, where healthspan stops increasing but lifespan increases. That seems possible in twin studies, where one twin’s choices cause a healthspan halt compared to the other twin’s choices.

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Reworking evolutionary theory

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Dr. Michael Skinner coauthored a 2021 review arguing for inclusion of epigenetic transgenerational inheritance into evolutionary theory:

“Over the past 50 years, molecular technology has been used to investigate evolutionary biology. Many examples of finding no correlated genetic mutations or a low frequency of DNA sequence mutations suggest that additional mechanisms are also involved.

  • Identical twins have essentially the same genetics, but generally develop discordant disease as they age.
  • Only a low frequency (generally 1% or less) of individuals that have a specific disease have a correlated genetic mutation.
  • Dramatic increases in disease frequency in the population cannot be explained with genetics alone.

DNA methylation, histone modifications, changes to chromatin structure, expression of non-coding RNA, and RNA methylation can directly regulate gene expression independent of DNA sequence. These different epigenetic factors do not only act independently, but integrate with each other to provide a level of epigenetic complexity to accommodate the needs of cellular development and differentiation.

dvab012f1

Environmental epigenetics is the primary molecular mechanism in any organism that is used to promote physiological and phenotypic alterations. Actions of environmental factors early in development can permanently program the cellular molecular function, which then impacts later life disease or phenotypes.

dvab012f2

Integration of epigenetics and genetics contribute to a Unified Theory of Evolution that explains environmental impacts, phenotypic variation, genetic variation, and adaptation that natural selection acts on. The current review expands this proposed concept and provides a significant amount of supporting literature and experimental models to support the role of environmentally induced epigenetic transgenerational inheritance in evolution.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8557805/ “Role of environmentally induced epigenetic transgenerational inheritance in evolutionary biology: Unified Evolution Theory”

Organisms cited in this review’s references are similar to humans in ancestral influences and developmental influences during the first 1000 days of our lives. Humans are different in that even after all these influences, we can choose to influence our own change and individually evolve. We can also change our internal environments per Switch on your Nrf2 signaling pathway and An environmental signaling paradigm of aging.

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Remembering encounters provides future benefits

gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Glutamate, Immune system, Memory, Neurochemicals, Stress, Testosterone , ,

Two 2021 papers on trained immunity, with the first a review:

“Effective memory immune responses rely on interaction between innate and adaptive immune cells. While activation of innate immunity provides the first line of defense against infections, it also primes the adaptive immune response.

Adaptive immunity can enhance antimicrobial machinery of innate cells, making them more effective at clearing pathogenic microorganisms. An additional layer of complexity adds to this network of interactions, with innate cells adopting a memory phenotype, which used to apply to only adaptive immunity. Furthermore, non-immune cells can develop some features of this memory-like phenotype.

fimmu-12-745332-g001

Cell subsets in which trained immunity has been described. Different stimuli including Bacillus Calmette Guerin (BCG), β-glucan, cytokines, cytomegalovirus (CMV), and bacterial components can induce a trained immunity phenotype. A common hallmark of trained immunity in these cases is H3K4me3 in promoters of genes encoding for different cytokines.

  • Mechanisms Underlying Establishment of Trained Immunity
  • Trained Immunity in Neutrophils
  • Trained Immunity in Monocytes and Macrophages: General Features
  • Metabolic Pathways Involved in Training of Monocytes and Macrophages
  • Hormonal Control of Trained Immunity Responses in Monocytes and Macrophages
  • Trained Immunity on Alveolar Macrophages and Involvement of Resident Cells
  • Trained Immunity in NK Cells
  • Trained Immunity in Innate Lymphoid Cells
  • Trained Immunity on Hematopoietic Stem Cells
  • Trained Immunity in Bronchial Epithelial Cells
  • Trained Immunity in Skin Stem Cells
  • Trained Immunity in the Gastrointestinal Tract
  • Immunity Training Against Protozoan-Mediated Pathologies
  • Trained Immunity in Non-Infectious Pathologies

Many gaps of knowledge remain in this field. For example, how long changes associated to trained immunity last, and if, in addition to epigenetic modulation, there are other post-translational modifications on proteins relevant for induction of trained immunity.”

https://www.frontiersin.org/articles/10.3389/fimmu.2021.745332/full “Molecular and Cellular Mechanisms Modulating Trained Immunity by Various Cell Types in Response to Pathogen Encounter”

This second paper was a human study cited for its glutathione findings as follows:

  • “Plasma concentration of IL-1β from BCG-vaccinated individuals are positively associated with serum glutathione concentrations.
  • Trained immunity up-regulates expression of genes involved in glutathione metabolism, suggesting an increase in glutathione synthesis and a higher glutathione recycling rate.
  • Single nucleotide polymorphisms in these genes are associated with changes in pro-inflammatory cytokine production after in vitro training by β-glucan and BCG.

Enzymes whose activities are dependent on glutathione could be used as novel targets to modulate trained immunity.”

IL-1β production

“We found a positive association between plasma glutathione concentration and ex vivo IL-1β production 90 days after BCG vaccination upon in vitro exposure to heterologous stimulus Staphylococcus aureus. Up-regulation of IL-1β production by BCG vaccination was also positively associated with circulating concentrations of other metabolites involved in glutathione metabolism, such as methionine, cysteine, glutamate, and glycine.

GSH metabolism was associated with trained immunity traits in 278 healthy individuals. Trained immunity mechanisms that are shaped by GSH metabolism remain to be further explored.”

https://www.mdpi.com/2073-4409/10/5/971/htm “Glutathione Metabolism Contributes to the Induction of Trained Immunity”

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Endless shingles

gettingwell4 2-3 stars Required further work, Epigenetics, Immune system, Stress , ,

This 2021 review subject was the follow-on condition of chicken pox:

“Varicella-zoster virus (VZV) is a pathogenic human alpha herpes virus which is a significant cause of morbidity. VZV causes a primary infection, usually in children, called varicella (chicken pox), following which it establishes ganglionic latency in neurons. Latency is established in ganglia throughout the entire neuroaxis including dorsal root ganglia, trigeminal ganglia, and also autonomic ganglia including enteric ganglia.

After a variable period, which can span several decades, VZV may reactivate to cause the well-recognised syndrome of herpes zoster (shingles), which is an extremely painful vesicular rash. While viral reactivation may occur spontaneously, it can also follow one or more triggering factors such as diminished cell-mediated immunity to the virus as occurs with older age or immunosuppression due to drug treatment or disease, X-ray irradiation, infection, trauma, or malignancy.

The disease spectrum caused by VZV reactivation is much wider than previously thought. A possible diagnosis of VZV reactivation-induced neurological disease should be considered in all cases of undiagnosed acute, subacute or chronic brain or spinal cord syndromes, particularly if there is an accompanying cerebrospinal fluid (CSF) pleocytosis.

Virus latency and reactivation is associated with specific modifications of bound histones. Consensus is that CpG island methylation is not involved.

Precise immune cells and immune mediators required for protective immunity in primary infection versus reactivation have not been clarified. Individual contributions from different cell types, including lymphocytes, macrophages, plasmacytoid dendritic cells, and epithelial and endothelial cells, which are all present in human ganglia, remains insufficiently understood and explored.

Immunological evaluation revealed the presence of VZV DNA as well as an immunological cell infiltrate composed of CD4 T cells, CD8 T cells, and CD20 B cells. This provided somewhat surprising evidence of an ongoing immunological reaction and inflammation years after the reactivation of VZV from latency.

Latency is characterized by maintenance of the virus genome in an endless (episomal) configuration. Since alpha human herpes virus latency is established so early in life, it is unlikely that viral latency can be completely prevented.”

https://www.mdpi.com/1999-4915/13/10/2018/htm “Recent Issues in Varicella-Zoster Virus Latency”

More investigation was needed in working backwards from recent reports of shingles outbreaks to activation causes. Common lab tests easily provide evidence of immune cell populations.

So what happened to cause removal of immune protective mechanisms that prevented varicella-zoster virus reactivation? It wasn’t the X-ray etc. reasons listed above.

Recent shingles outbreaks are telling an important story. Who is looking into it?

These and other researchers won’t find evidence if they don’t get out of their labs and look at people’s cases. They’ll also need to report findings regardless of the political climate.

IMG_20210608_132139

Do genes determine monogamy / polygamy?

gettingwell4 4-5 stars Advanced knowledge, Brain development, Dopamine, Epigenetics, Immune system, Limbic system, Neurochemicals , , , , ,

This 2021 rodent study developed epigenetic clocks for deer mice:

“We have undertaken a genome-wide analysis of DNA methylation in Peromyscus, spanning different species, stocks, sexes, tissues, and age cohorts. We present CpGs and enriched pathways that relate to different conditions such as chronological age, high altitude, and monogamous behavior.

  • Analysis involved tails, whole brain, and liver samples that are not major target tissues for sex hormones. This implies that sex-specific patterns of methylation are inflicted early during development, and persist at adulthood.
  • Altitude-specific age-related changes are adjacent to genes that play a role in brain development, immune system functioning, and T-cell development.
  • Comparison of brain specimens between older P. leucopus and P. maniculatus indicated that in the latter, coordination of the unfolded protein response is compromised, and evidence of neurodegenerative pathology was obtained.
  • Our study involved three monogamous (P. californicus, P. polionotus, and P. eremicus) and two polygamous (P. maniculatus and P. leucopus) species. The most significant EWAS hits for monogamy included decreased methylation in Zeb2 intron, a key regulator of midbrain dopaminergic neuron development. These results derived from tail tissues, suggesting that inherent differences in bonding behavior instruct specific epigenetic changes in peripheral tissues that may be translated into distinct physiological outcomes. Whether this is due to differential regulation of specific neurohormonal circuits in response to hormones and neurotransmitters related to bonding, and what the exact physiological outputs are, remains to be determined.

Our study provided the first epigenetic clock for Peromyscus, and illustrated the hierarchical association between various biological variables in determining methylation profiles across different scales of biological organization.”

https://link.springer.com/article/10.1007/s11357-021-00472-5 “Methylation studies in Peromyscus: aging, altitude adaptation, and monogamy”

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All about the betaine, Part 2

gettingwell4 4-5 stars Advanced knowledge, Brain development, Epigenetics, Hippocampus, Immune system, Limbic system, Stress , , ,

Continuing Part 1 by curating a partial outline of a 2021 review:

“This review focuses on the biological and beneficial effects of dietary betaine (trimethylglycine), a naturally occurring and crucial methyl donor.

Betaine has a neuroprotective role, preserves myocardial function, and prevents pancreatic steatosis. Betaine also attenuates oxidant stress, endoplasmic reticulum stress, inflammation, and cancer development. Betaine:

  • Protects against Development of Alcohol-Induced Hepatic Steatosis
  • Protects against Detrimental Effects of HCV and Ethanol on Innate Immunity
  • Maintains Intestinal Epithelial Barrier Integrity
  • Maintains Adipose Function

biology-10-00456-g002

Human intervention studies showed no adverse effects with 4 g/day supplemental administration of betaine in healthy subjects. However, overweight subjects with metabolic syndrome showed a significant increase in total and LDL-cholesterol concentrations. These effects were not observed with 3 g/day of betaine administration.

We suggest betaine as a promising therapeutic for clinical use to treat these aforementioned diseases as well as other liver-/non-liver-related diseases and conditions.”

https://www.mdpi.com/2079-7737/10/6/456/htm “Beneficial Effects of Betaine: A Comprehensive Review”

This review cited a 2020 study Transgenerational Inheritance of Betaine-Induced Epigenetic Alterations in Estrogen-Responsive IGF-2/IGFBP2 Genes in Rat Hippocampus (not freely available):

“Hippocampal expression of aromatase, estrogen receptor α, and estrogen-related receptor β is downregulated in F1, together with estrogen-responsive insulin-like growth factor 2/insulin-like growth factor binding protein 2 (IGF-2/IGFBP2) genes. However, all these genes are upregulated in F2, which follows the same pattern of F0.

Imprinting control region of IGF-2 gene is hypomethylated in F1 but hypermethylated in F2 and F0. In contrast, the promoter DNA methylation status of all affected genes is hypermethylated in F1 but hypomethylated in F2 and F0.”

  • Intergenerational flip-flops of F0 phenotypes to opposite F1 phenotypes back to F0 phenotypes in the F2 generation can’t conclusively demonstrate transgenerational epigenetic inheritance of alterations due to betaine consumption during pregnancy.
  • Those researchers had to continue on to a F3 female generation for transgenerational results, because F2 generation cells were present in F1 fetuses, and were potentially affected during pregnant F0 treatments.

I came across this paper through a citation chain initiated by Dr. Paul Clayton’s blog post Foie Gras:

“Thanks to our modern diet and lifestyle, nonalcoholic fatty liver disease (NAFLD) is now reckoned to affect an astonishing quarter of the world’s population.”

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The Illusion of Knowledge: The paradigm shift in aging research that shows the way to human rejuvenation

gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Stress , , , , , ,

Dr. Harold Katcher increased interviews to coincide with release of his book this month. Here’s one in four parts that provides highlights of his rejuvenation research progress:

Previously curated papers of his work include:

Epigenetic clocks so far in 2021

gettingwell4 5+ stars Premium, Brain development, Cerebellum, Epigenetics, Hippocampus, Hypothalamus, Immune system, Limbic system, Lower brain, Memory, Stress, Telomeres , , , , , , , , ,

2021’s busiest researcher took time out this month to update progress on epigenetic clocks:

Hallmarks of aging aren’t all associated with epigenetic aging.

epigenetic aging vs. hallmarks of aging

Interventions that increase cellular lifespan aren’t all associated with epigenetic aging.

epigenetic aging vs. cellular lifespan

Many of his authored or coauthored 2021 papers developed human / mammalian species relative-age epigenetic clocks.

epigenetic clock mammalian maximum lifespan

Relative-age epigenetic clocks better predict human results from animal testing.

pan-mammalian epigenetic clock

Previously curated papers that were mentioned or relevant included:

All about vasopressin

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This 2021 review subject was vasopressin:

“Vasopressin is a ubiquitous molecule playing an important role in a wide range of physiological processes, thereby implicated in pathomechanisms of many disorders. The most striking is its central effect in stress-axis regulation, as well as regulating many aspects of our behavior.

Arginine-vasopressin (AVP) is a nonapeptide that is synthesized mainly in the supraoptic, paraventricular (PVN), and suprachiasmatic nucleus of the hypothalamus. AVP cell groups of hypothalamus and midbrain were found to be glutamatergic, whereas those in regions derived from cerebral nuclei were mainly GABAergic.

In the PVN, AVP can be found together with corticotropin-releasing hormone (CRH), the main hypothalamic regulator of the HPA axis. The AVPergic system participates in regulation of several physiological processes, from stress hormone release through memory formation, thermo- and pain regulation, to social behavior.

vasopressin stress axis

AVP determines behavioral responses to environmental stimuli, and participates in development of social interactions, aggression, reproduction, parental behavior, and belonging. Alterations in AVPergic tone may be implicated in pathology of stress-related disorders (anxiety and depression), Alzheimer’s, posttraumatic stress disorder, as well as schizophrenia.

An increasing body of evidence confirms epigenetic contribution to changes in AVP or AVP receptor mRNA level, not only during the early perinatal period, but also in adulthood:

  • DNA methylation is more targeted on a single gene; and it is better characterized in relation to AVP;
  • Some hint for bidirectional interaction with histone acetylation was also described; and
  • miRNAs are implicated in the hormonal, peripheral role of AVP, and less is known about their interaction regarding behavioral alteration.”

https://www.mdpi.com/1422-0067/22/17/9415/htm “Epigenetic Modulation of Vasopressin Expression in Health and Disease”

Find your way, regardless of what the herd does.

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Part 2 of Improving epigenetic clocks’ signal-to-noise ratio

gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Immune system , ,

Another excellent blog post by Josh Mitteldorf, A New Approach to Methylation Clocks, that curated the same study:

“The Levine/Horvath PhenoAge epigenetic clock was calibrated using a combination of metabolic factors that correlate with health, including inflammation, DNA transcription, DNA repair, and mitochondrial activity.

Evolution is not an engineer. Living things are not constructed out of parts that are separately optimized for exactly one function.

Every molecule has multiple functions. Every function is regulated by multiple pathways.

For clock technology, using individual CpGs for a starting point may not be optimal. We suspect that CpGs, like other biological entities, work together closely in teams.

CpGs on a team might vary slightly from one individual to the next. But the team has a function and an identity and a signature that is robust. We expect the team to function more consistently than any of its individual members.

The peer-reviewed version of her paper will be published shortly. Full details of algorithms will be available on GitHub, and script in the R programming language will be released for use of other researchers. If principal component analysis clocks correlate well with previously validated clocks but offer tighter uncertainties, we’ll know we’re on the right track.”

Best wishes for Josh to recover from a bike accident.

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Your pet’s biological age

gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Immune system, Telomeres , , , ,

This 2021 cat study developed human-comparable epigenetic clocks:

“We aimed to develop and evaluate epigenetic clocks for cats, as such biomarkers are necessary for translating promising anti-aging interventions from humans to cats and vice versa. We also provided the possibility of using epigenetic aging rate of cats to inform on feline health, for which a quantitative measure is presently unavailable. Specifically, we present here DNA methylation-based biomarkers (epigenetic clocks) of age for blood from cats.

Maximum lifespan of cats is 30 years according to the animal age data base (anAge), but most cats succumb to diseases before they are 20 years old. Age is the biggest risk factor for a vast majority of diseases in animals, and cats are no exception.

Interventions to slow aging are being sought. Ideally, testing should occur in species that are evolutionarily close to humans, similar in size, have high genetic diversity, and share the same environment as humans. It has been recognized that domestic dogs fulfill these criteria.

Investigations have yet to be extended to cats although they share similar environments and living conditions with their human owners. Identification of environmental factors and living conditions that affect aging, as well as potential mitigation measures, can be achieved by proxy with cats.

The human-cat clock for relative age exhibited high correlation regardless of whether analysis was applied to samples from both species or only to cat samples. This demonstrated that relative age circumvented skewing that is inherent when chronological age of species with very different lifespans is measured using a single formula.

Evidence is compelling that epigenetic age is an indicator of biological age. These results are consistent with the fact that epigenetic clocks developed for one mammalian species can be employed – to a limited extent – to other species, and reveal association of DNA methylation changes with age.

Human epigenetic age acceleration is associated with a wide array of primary traits, health states, and pathologies. While it is still unclear why age acceleration is connected to these characteristics, it does nevertheless suggest that extension of similar studies to cats may allow for development of epigenetic age acceleration as a surrogate or indicator of feline biological fitness.”

https://link.springer.com/article/10.1007%2Fs11357-021-00445-8 “Epigenetic clock and methylation studies in cats”

As noted earlier this summer in Smoke and die early, while your twin lives on, Dr. Steve Horvath is on a torrid publishing streak this year. He’s made it questionable for study designs based on published science to omit epigenetic clocks.

I titled this post Your pets because I’m too allergic to have cats, dogs, etc. live with me. Maybe this year’s focus on making my gut microbiota happy will change that?

My pets live free:

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No magic bullet, only magical thinking

gettingwell4 4-5 stars Advanced knowledge, Cerebrum, Dopamine, Epigenetics, Hypothalamus, Immune system, Limbic system, Memory, Neurochemicals, Stress , ,

Consider this a repost of Dr. Paul Clayton’s blog post The Drugs Don’t Work:

“The drug industry has enough funds to:

  • Rent politicians;
  • Subvert regulatory agencies;
  • Publish fake data in the most august peer-reviewed literature; and
  • Warp the output of medical schools everywhere.

Their products are a common cause of death. Every year, America’s aggressively modern approach to disease kills over 100,000 in-hospital patients, and twice that number of out-patients.

In 1900, a third of all deaths occurred in children under the age of 5. By 2000 this had fallen to 1.4%. The resulting 30-year increase in average life expectancy fed into the seductive and prevailing myth that we are all living longer; which is manifestly untrue. Improvements in sanitation were far more significant in pushing infections back than any medical developments.

There is currently no pharmaceutical cure for Alzheimer’s or Parkinsonism, nor can there be when these syndromes are in most cases driven by multiple metabolic distortions caused by today’s diet. The brain is so very complex, and it can go wrong in so many ways. The idea that we can find a magic bullet for either of these syndromes is ill-informed and philosophically mired in the past.

It is also dangerous. There is a significant sub-group of dementia sufferers whose conditions are driven and exacerbated by pharmaceuticals. Chronic use of a number of commonly prescribed drugs – and ironically, anti-Parkinson drugs – increases the risk of dementia by roughly 50%.

Big Pharma’s ability to subvert regulatory authorities is even more dangerous. The recent FDA approval of Biogen’s drug aducanumab is a scandal; not one member of the FDA Advisory Committee voted to approve this ineffective product, and three of them resigned in the aftermath of the FDA’s edict. This ‘anti-Alzheimer’s’ drug, which will earn Biogen $56,000 / patient / year, was licensed for financial reasons; it reduced amyloid plaque but was clinically ineffective.

So did the eagerly awaited gantenerumab and solanezumab. But they, too, failed to produce any significant clinical benefit.”

A knee-replacement patient enduring her daily workout

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PTSD susceptibility?

gettingwell4 2-3 stars Required further work, Amygdala, Epigenetics, Hippocampus, Limbic system, Memory, Primal Therapy, Stress , , , , , , ,

This 2021 rodent study investigated post-traumatic stress disorder (PTSD) susceptibility:

“PTSD is an incapacitating trauma-related disorder, with no reliable therapy. We show distinct DNA methylation profiles of PTSD susceptibility in the nucleus accumbens (NAc). Data analysis revealed overall hypomethylation of different genomic CpG sites in susceptible animals.

Is it possible to treat PTSD by targeting epigenetic processes? Such an approach might reverse genomic underpinning of PTSD and serve as a cure.

To test plausibility of such an approach, a reliable animal (rat) model with high construct validity is needed. Previously, we reported one such model, which uses predator-associated trauma, and cue reminders to evoke recurring trauma. This simulates clinical PTSD symptoms including re-experiencing, avoidance, and hyperarousal.

Individual PTSD-like (susceptible) behavior is analyzed, enabling identification of susceptible animals separately from those that are non-PTSD-like (resilient). This model captures salient features of this disorder in humans, in which only a fraction of trauma victims develop PTSD, while others are resilient.

experimental model

Sprague–Dawley rats were exposed to trauma and to three subsequent trauma-associated reminders. Freezing behavior was measured under conditions of:

  • Exploration;
  • Social interaction (with a companion); and
  • Hyperarousal.

Controls were exposed to identical conditions except for the traumatic event.

PTSD-like behavior of each animal was compared with baseline and with the population. Two unambiguous sub-populations were identified, resilient and susceptible.

After exposure to trauma and its reminders, susceptible animals showed an increase from baseline in freezing behavior, and over time in all three behavioral tests, as opposed to resilient and control groups.

DMRs

Differentially methylated sites in susceptible and resilient animals compared to control group.

Although we focused in this study on DNA methylation changes that associate with susceptibility, we also report unique changes in DNA methylation that occur in resilient animals. Inhibition of critical genes that are downregulated in susceptible animals convert resilient animals to become susceptible.”

https://www.researchgate.net/publication/353192082_Reduction_of_DNMT3a_and_RORA_in_the_nucleus_accumbens_plays_a_causal_role_in_post-traumatic_stress_disorder-like_behavior_reversal_by_combinatorial_epigenetic_therapy “Reduction of DNMT3a and RORA in the nucleus accumbens plays a causal role in post-traumatic stress disorder-like behavior: reversal by combinatorial epigenetic therapy” (registration required)

Rodents with the same genetics and environment displayed individual differences in their responses to traumatic events. Researchers, provide evidence for that before venturing elsewhere.

Not sure why it took 3+ years for this study received in November 2017 to finally be published in July 2021. Sites other than https://doi.org/10.1038/s41380-021-01178-y are more transparent about their peer review and publication processes.

No causes for PTSD susceptibility were investigated. PTSD effects and symptoms aren’t causes, notwithstanding this study’s finding that:

“Our results support a causal role for the NAc as a critical brain region for expression of PTSD-like behaviors, and a role for programming genes by DNA methylation in the NAc in development of PTSD-like behaviors.”

Can’t say that I understand more about causes for PTSD susceptibility now than before I read this study. Researchers attaching significance to gene functional groups seemed like hypothesis-seeking efforts to overcome limited findings.

Will this study’s combination of a methyl donor with a Vitamin A metabolite address PTSD causes in humans? If it only temporarily alleviates symptoms, what lasting value will it have?

Several brain and body areas that store traumatic memories other than the nucleus accumbens were mentioned in The role of recall neurons in traumatic memories. A wide range of epigenetic memory storage vehicles is one reason why effective human therapies need to address each individual, their whole body, and their entire history.

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