Non-CpG DNA methylation

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

Part 3 of Rejuvenation therapy and sulforaphane

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

Aging as an unintended consequence

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

Linear thinking about biological age clocks

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

The epigenetics of perinatal stress

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 the early experience, the changes in gene expression programming must be stable. Although … Continue reading The epigenetics of perinatal stress

Do epigenetic clocks measure causes or effects?

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?

A blood plasma aging clock

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

Using oxytocin receptor gene methylation to pursue an agenda

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

A GWAS meta-analysis of two epigenetic clocks

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

A strawman argument against epigenetic clocks

This 2019 review of epigenetic clocks by Washington cancer researchers ignored the elephant in the room, and repeatedly returned to an argument for randomness as a cause for aging and disease: “A time-dependent stochastic event process, like epigenetic drift, could lead to cancer formation through the accumulation of random epigenetic alterations that, through chance, eventually … Continue reading A strawman argument against epigenetic clocks