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 … Continue reading Your pet’s biological age
This May 3, 2020 two-hour video on Optimizing Biological Age was instructive: Content was great! I recommend the longish Q & A, especially at 1:23 regarding inflammation. It was a snapshot in that researchers on this conference call were interested in improving people’s health. Few recognized at the time a globally coordinated effort to herd … Continue reading A biological age snapshot from a year ago
A fast-paced 2020 presentation on studies underlying the plasma portion of Levine’s PhenoAge epigenetic clock: Watch it on YouTube to read comments and replies.
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
A 2019 UCLA study introduced a derivative of the epigenetic clock named GrimAge: “DNAm GrimAge, a linear combination of chronological age, sex, and DNAm-based surrogate biomarkers for seven plasma proteins and smoking pack-years, outperforms all other DNAm-based biomarkers, on a variety of health-related metrics. An age-adjusted version of DNAm GrimAge, which can be regarded as … Continue reading Statistical inferences vs. biological realities
This 2016 US/Italy article was written from a perspective of regenerative bioengineering: “Higher levels beyond molecular can have their own unique dynamics that offer better (e.g. more parsimonious and potent) explanatory power than models made at lower levels. Biological systems may be best amenable to models that include information structures (organ shape, size, topological arrangements … Continue reading A top-down view of biological goal-directed mechanisms
This 2017 UK/Spanish review subject was biological variability: “No two cells in a cellular population are the same, and no two individuals of a multi-cellular species are identical-not even if they share the same genetic makeup like monozygotic twins or cloned animals. Epigenetic and gene expression variability are key contributors to phenotypic differences. There are … Continue reading A review of biological variability
This 2015 Zurich human review addressed: “A remarkable lack of discussion on the meaning and interpretation of frequently used hormone ratios. The interpretation of hormone ratios is complicated and in many cases not sufficiently supported from a theoretical point of view. Based on the assumption that the balance between two interdependent hormones determines their eventual … Continue reading Are hormone ratios useful in explaining health? Behavior? Neurobiology? Anything?
How Trauma and Resilience Cross Generations “The purpose of epigenetic changes, I think, is simply to increase the repertoire of possible responses. So let’s say, for some reason, your parents transmitted to you biologic changes that are very appropriate to starvation, but you don’t live in a culture where food is not plentiful. You’re just … Continue reading An interview with Dr. Rachel Yehuda on biological and conscious responses to stress
I curated this 2015 Georgia human study only for its use of two methods of estimating biological age. The researchers misguidedly used these techniques to help paint a scientific patina on an agenda. One of the methods was originated by a coauthor of The degree of epigenetic DNA methylation may be used as a proxy … Continue reading Using epigenetic DNA methylation markers to estimate biological age
This 2015 New Zealand human study used the same subjects of the More from the researchers that found people have the same personalities at age 26 that they had at age 3 study. These researchers used 10 biologic age markers of subjects at age 38 to find that their biological ages ranged from 28 to … Continue reading A study of biological aging in young adults with limited findings
This 2015 Harvard/MIT rodent study was of long (more than 200 nucleotides) noncoding (non-protein coding) RNAs (ribonucleic acids). These are of interest because: “Within the mammalian body, the largest repertoire and diversity of lncRNA genes outside the germ line occurs in the brain, where lncRNAs exhibit regional and cell-specific localization. The expression patterns of lncRNAs … Continue reading RNA as a proxy signal for context-specific biological activity
This fascinating 2014 human study developed the new use of a somewhat intuitive marker of aging. The researchers used the degree of methylation – an epigenetic chemical modification of DNA – as an epigenetic clock to measure biological age. The researchers found that, on average, the epigenetic age of the liver increased by 3.3 years … Continue reading The degree of epigenetic DNA methylation may be used as a proxy to measure biological age
This 2014 fruit fly study found: “A biologically relevant event such as finding food under starvation conditions or being poisoned can drive long-term memory in a single training session.” I don’t think that we need to discover at these extremes, though, whether or not the finding has human applicability. We do know from the Dutch … Continue reading A biologically relevant event can drive long-term memory in a single training session
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