Our sex organs could be pacemakers for aging through our body

Another year, another gray hair. Another wrinkle. Maybe another few inches on the ol’ spare tire.Yet on the inside, aging isn’t quite as lock-step. While some of your organs are rapidly adding miles on their odometers, others tap the brakes on their biological birthdays.To build the foundations for an aging atlas of the body, a team led by researchers from the Sanford Burnham Prebys Medical Discovery Institute developed a method for quantifying structural aging of tissues based on a snapshot of their cellular architecture.Aging can mean different things, depending on how we measure it. We can count candles on a cake, which is a linear progression that goes up by one each year. We can also count the accumulation of non-mutational edits carried out on a cell’s DNA, giving us a genetic – or “epigenetic” – age.In this case, the framework is based on physical features that are essential for cellular functioning. By examining patches of stained tissue in histopathological samples across a range of age groups, the team found that they could correlate the changes with characteristics we’d associate more closely with aging – more inflammation, less energy, and poorer quality control.“Our goal is to understand how aging occurs at a structural level,” says senior author Sanju Sinha, a computational biologist at Sanford Burnham Prebys. “To do this, we needed thousands of normal organ tissues over a wide range of ages.”Applying their Pathology-based Structural Aging Rate framework to more than 25,000 post-mortem biopsies provided by nearly 1,000 adult donors, the team found a roller-coaster of aging trajectories across dozens of tissue types.Some, like our blood vessels, age fastest early in life. Organs such as the uterus pile on changes much later.Methods that rely on counting molecular edits to our genetic code tend to be trained on chronological aging, making them rather linear.This alternative approach needed no such training, allowing the researchers to uncover previously hidden signs of a bimodal pattern of aging in tissues like the ovaries, which rises in the thirties, dips in the forties, and then rises again during menopause.“Once we understood these patterns, we could use the gene expression and regulation data from the same Genotype-Tissue Expression Project cohort to see what major molecular changes occur during accelerated aging,” says Sinha.It wasn’t exactly a free-for-all of boom or bust. Amid the chaos of aging architecture were clear genetic patterns.It’s to be expected that tissues in the same organ would match their aging processes. Yet a cross-organ analysis found a level of coordination across distinctly different tissues linked by sex hormones. Individuals who showed signs of aging in their esophagus, for example, showed a coordinated pattern in their prostate.“Overall, this suggests that structural aging of digestive and reproductive tissues may be linked through a hormonal signaling axis whose decline drives synchronized structural deterioration across organ system boundaries,” the researchers argue.Meaning our sex organs act as a kind of pacemaker for aging. More than half of the tissues the team studied matched architectural changes observed in the ovaries.Practically speaking, this could give researchers better tools to develop therapies that ease aging in one part of our body by targeting another.So next time you wish your stomach happy birthday with a slice of cake, don’t forget to light a candle for your ovaries or testicles. They’ve earned it.This research was published in Nature Aging.Source: EurekAlert