This 2017 Korean review compared and contrasted CpG and non-CpG DNA methylation: “Non-CpG methylation is restricted to specific cell types, such as pluripotent stem cells, oocytes, neurons, and glial cells. Accumulation of methylation at non-CpG sites and CpG sites in neurons seems to be involved in development and disease etiology. Non-CpG methylation is established during … Continue reading Non-CpG DNA methylation
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 … Continue reading Part 2 of Improving epigenetic clocks’ signal-to-noise ratio
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 … Continue reading PTSD susceptibility?
This 2021 computational study investigated several methods of improving epigenetic clock reliability: “Epigenetic clocks are widely used aging biomarkers calculated from DNA methylation data. Unfortunately, measurements for individual CpGs can be surprisingly unreliable due to technical noise, and this may limit the utility of epigenetic clocks. Noise produces deviations up to 3 to 9 years … Continue reading Improving epigenetic clocks’ signal-to-noise ratio
This 2021 human study found: “We report on a randomized controlled clinical trial conducted among 43 healthy adult males between the ages of 50-72. The 8-week treatment program included diet, sleep, exercise and relaxation guidance, and supplemental probiotics and phytonutrients. This is the first randomized controlled study to suggest that specific diet and lifestyle interventions … Continue reading Repositioning DNA methylation
This 2021 study subject was bats: “Exceptionally long-lived species, including many bats, rarely show overt signs of aging, making it difficult to determine why species differ in lifespan. Here, we use DNA methylation (DNAm) profiles from 712 known-age bats, representing 26 species, to identify epigenetic changes associated with age and longevity. Hypermethylated age- and longevity-associated … Continue reading A bat epigenetic clock
This 2021 rodent study investigated mechanisms of sulforaphane’s persistent cardiac protection: “Sulforaphane (SFN) reduced Ang II‐induced CpG hypermethylation and promoted Ac‐H3 [histone H3 acetylation] accumulation in the Nrf2 promoter region, accompanied by inhibition of global DNMT [DNA methyltransferase] and HDAC [histone deacetylase] activity, and a decreased protein expression of key DNMT and HDAC enzymes. SFN … Continue reading Eat broccoli sprouts for your heart
This 2021 rodent study made old females out of young females by removing their ovaries, which induced osteoporosis. They then demethylated the Nrf2 gene promoter with exercise, increasing its expression, which reversed osteoporosis: “Nrf2 repression due to aberrant Dnmt elevation and subsequent Nrf2 promoter hypermethylation is an important epigenetic feature of osteoporosis (OP) pathogenesis. Ovariectomized … Continue reading Reversing osteoporosis with Nrf2
This 2020 Norwegian study investigated current epigenetic clock technology: “Epigenetic clocks are based on CpGs from the Illumina HumanMethylation450 BeadChip (450 K) which has been replaced by the latest platform, Illumina MethylationEPIC BeadChip (EPIC). EPIC is a major improvement over its predecessor, 450 K (> 450,000 CpGs), in terms of number of probes (> 850,000 CpGs) and genomic coverage … Continue reading Epigenetic clock technology
This 2020 US/Sweden/Denmark human study measured twins during their old age: “We evaluate individual differences in DNA methylation at individual CpG sites across the methylome across 10 years in two Scandinavian samples of same‐sex aging twins. We test two competing hypotheses about the longitudinal stability and change in DNA methylation: The contribution of genetic influences … Continue reading A cherry-picked DNA methylation study
This 2020 Rutgers rodent study explored topical application of sulforaphane to prevent UVB-induced skin carcinogenesis: “We investigated the transcriptomic and DNA methylomic changes during tumor initiation, promotion, and progression and its impact and reversal by sulforaphane (SFN). The production of ROS and inflammation are closely linked to UVB-induced carcinogenesis. SFN protects skin cells from UVB-induced … Continue reading Topical sulforaphane protects skin
Part 1 focused on the study’s clinical biomarkers. Part 2 highlighted its epigenetic clocks. Now we’ll look at rejuvenation of cognitive function. Charts for this study’s most relevant human aging applications – measured by the new human-rat relative biological age clock – were in supplementary data due to combining study untreated tissue samples into clock … Continue reading Part 3 of Rejuvenation therapy and sulforaphane
The coauthors of 2018’s The epigenetic clock theory of aging reviewed progress that’s been made todate in understanding epigenetic clock mechanisms. 1. Proven DNA methylation features of epigenetic clocks: “Methylation of cytosines is undoubtedly a binary event. The increase in epigenetic age is contributed by changes of methylation profiles in a very small percent of … Continue reading Aging as an unintended consequence
This 2020 review by a Hong Kong company’s researchers compared and contrasted measures of biological age: “More than a dozen aging clocks use molecular features to predict an organism’s age, each of them utilizing different data types and training procedures. We offer a detailed comparison of existing mouse and human aging clocks, discuss their technological … Continue reading Linear thinking about biological age clocks
This 2019 McGill review discussed long-lasting effects of perinatal stress: “Epigenetic processes are involved in embedding the impact of early-life experience in the genome and mediating between social environments and later behavioral phenotypes. Since these phenotypes are apparent a long time after early experience, changes in gene expression programming must be stable. Although loss of … Continue reading The epigenetics of perinatal stress
