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New evidence that adult stem cells are critical to human aging has recently been published on a study done on a super-centenarian woman that lived to be 115 years. At death, her circulating stem cell pool had declined to just two active stem cells from stem cell counts that are typically more than a thousand in younger adults. Super-centenarians have survived all the normal diseases that kill 99.9% of us before 100 years of age, so it has been a mystery as to what actually kills these hardy individuals. This recent data suggest that stem cell decline may be the main contributor to aging. If so, stabilizing stem cells may be the best thing one can do to slow your rate of aging.
There are many theories of aging that have been proposed. For example, damage to cells and tissues from oxidative stress has been one of the most popular fundamental theories of aging for more than half a century. Yet antioxidant substances or genes that code antioxidant enzymes have proven largely ineffective in slowing aging when tested in model animals. Thus, interest by scientists has shifted to other hypotheses that might provide a better explanation for the slow declines in function with age.
Stem cells provide one such promising mechanism of aging. Of course, we all know that babies are young and vigorous, independent of the age of their parents. This is because adults have embryonic stem cells that can generate young new cells needed to form a complete young baby. Indeed, these embryonic stem cells are the product of continuously evolving stem cell populations that go back to the beginning of life on earth over 3.5 billion years ago!
In adults, the mostly immortal embryonic stem cells give rise to mortal adult stem cells in all the tissues of the body. These adult stem cells can regenerate your cells and tissues as they wear out and need replacement. Unfortunate, adult stem cells also age, which leads to fewer cells and/or loss of function in cell replacement. As functional stem cells decline, skin and organs decline with age.
Blood from world’s oldest woman suggests life limit
Time Magazine: Long-Life Secrets From The 115-Year-Old Woman
Abstract
The somatic mutation burden in healthy white blood cells (WBCs) is not well known. Based on deep whole-genome sequencing, we estimate that approximately 450 somatic mutations accumulated in the nonrepetitive genome within the healthy blood compartment of a 115-yr-old woman. The detected mutations appear to have been harmless passenger mutations: They were enriched in noncoding, AT-rich regions that are not evolutionarily conserved, and they were depleted for genomic elements where mutations might have favorable or adverse effects on cellular fitness, such as regions with actively transcribed genes. The distribution of variant allele frequencies of these mutations suggests that the majority of the peripheral white blood cells were offspring of two related hematopoietic stem cell (HSC) clones. Moreover, telomere lengths of the WBCs were significantly shorter than telomere lengths from other tissues. Together, this suggests that the finite lifespan of HSCs, rather than somatic mutation effects, may lead to hematopoietic clonal evolution at extreme ages.
For many people, grabbing a hot drink in a disposable cup is part of their daily routine. Yet the container holding your coffee or tea may not be as harmless as it seems. New research suggests the very cup designed to keep your drink hot could also be releasing tiny plastic particles into it.
Not all disposable cups release microplastics at the same rate. Researchers found that the cup material and beverage temperature both affect how many tiny plastic particles leach into a drink. Although microplastics were detected across all temperatures tested, hotter beverages triggered significantly greater particle release.
Measuring less than 5 millimeters, microplastics have emerged as an increasing public health concern. These tiny particles can enter the body through food, beverages, or the air we breathe, where they may build up in organs including the lungs and digestive system and contribute to inflammation and other health problems.
The study combined evidence from previous research with new laboratory testing. Researchers first reviewed 30 published studies, compiling 237 observations to assess how variables such as water temperature and soaking time influenced microplastic release. They then tested two popular types of disposable cups, those made entirely of polyethylene (PE) and paper cups with a polyethylene coating, to compare how much microplastic each released.
Researchers found that hot water caused the surface of polyethylene (PE) cups to become increasingly rough and irregular, a sign of physical degradation that likely contributed to greater microplastic shedding. By comparison, paper cups coated with polyethylene maintained smoother surfaces with less visible damage, which may have helped limit the release of plastic particles.
The study estimated that a single 10-ounce hot beverage consumed each day could add hundreds of thousands of microplastic particles to a person's yearly intake. Drinks served in polyethylene (PE) cups were associated with roughly 360,000 particles per year, while polyethylene-coated paper cups were estimated to release about 240,000 annually.
The healthiest and most environmentally friendly choice is a reusable cup made from stainless steel, glass or ceramic. Because these materials are non-reactive, they won't break down or release chemicals or plastic particles when filled with hot beverages.
Maintaining a healthy weight is becoming increasingly uncommon, with only one in four U.S. adults falling into that category. New research suggests excess weight may be responsible for significantly more cancers than once thought. After analyzing data from more than 450,000 people, researchers estimated that excess body fat is linked to over 11% of all cancer cases, nearly twice earlier estimates.
Being alone isn't necessarily harmful, but feeling lonely may be. According to a new study, older adults who experience persistent loneliness may face a faster decline in both cognitive and physical health. The researchers found that loneliness remained strongly linked to poorer brain health and an increased risk of early death, regardless of how socially isolated a person was.