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
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clock technology: “Epigenetic clocks are based on CpGs from the Illumina HumanMethylation450 BeadChip (450 K) which has been replaced by the latest platform, Illumina MethylationEPIC BeadChip (EPIC).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 the number of probes (> 850,000 CpGs) and the … 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 the study’s untreated tissue samples into … 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
The founder of the PhenoAge epigenetic clock methodology authored this 2020 article: “The Ge[r]oscience paradigm suggests that targeting the aging process could delay or prevent the risk of multiple major age-related diseases. We need clinically valid measures of the underlying biological process and/or classification criteria for what it means to be biologically, rather than chronologically, … Continue reading Do epigenetic clocks measure causes or effects?
This 2019 Stanford human study developed an aging clock using blood plasma proteins: “We measured 2,925 plasma proteins from 4,331 young adults to nonagenarians [18 – 95] and developed a novel bioinformatics approach which uncovered profound non-linear alterations in the human plasma proteome with age. Waves of changes in the proteome in the fourth, seventh, … Continue reading A blood plasma aging clock
A pair of 2019 Virginia studies involved human mother/infant subjects: “We show that OXTRm [oxytocin receptor gene DNA methylation] in infancy and its change is predicted by maternal engagement and reflective of behavioral temperament.” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6795517 “Epigenetic dynamics in infancy and the impact of maternal engagement” “Infants with higher OXTRm show enhanced responses to anger and … Continue reading Using oxytocin receptor gene methylation to pursue an agenda
This 2019 UK human study conducted a meta-analysis of genome-wide association studies of two epigenetic clocks using 13,493 European-ancestry individuals aged between ten and 98 years: “Horvath-EAA, described in previous publications as ‘intrinsic’ epigenetic age acceleration (IEAA), can be interpreted as a measure of cell-intrinsic ageing that exhibits preservation across multiple tissues, appears unrelated to … Continue reading A GWAS meta-analysis of two epigenetic clocks
This 2019 review of epigenetic clocks by Washington cancer researchers ignored the elephant in the room: Their epigenetic drift paradigm is generally inapplicable to humans because the vast majority of our cells don’t divide/proliferate. They repeatedly returned to an argument for randomness as a cause for aging and disease: “A time-dependent stochastic event process, like … Continue reading A strawman argument against epigenetic clocks
This 2019 Singapore human study used Diffusion Tensor Imaging on 5-to-17-day old infants to find: “Our findings showed evidence for region-specific effects of genotype and GxE on individual differences in human fetal development of the hippocampus and amygdala. Gene x Environment models outcompeted models containing genotype or environment only, to best explain the majority of … Continue reading Do genes or maternal environments shape fetal brains?
This 2019 UK/Canada/Germany human study investigated thirteen developmental disorders to identify genes that changed aspects of the epigenetic clock: “Sotos syndrome accelerates epigenetic aging [+7.64 years]. Sotos syndrome is caused by loss-of-function mutations in the NSD1 gene, which encodes a histone H3 lysine 36 (H3K36) methyltransferase. This leads to a phenotype which can include: Prenatal and … Continue reading Developmental disorders and the epigenetic clock