LA JOLLA—The Salk Institute will establish a world-class San Diego Nathan Shock Center (SD-NSC), a consortium with Sanford Burnham Prebys Medical Discovery Institute and the University of California San Diego (UC San Diego), to study cellular and tissue aging in humans. The Center will be funded by a grant from the National Institute on Aging (NIA) of the National Institutes of Health expected to total $5 million over the next 5 years (NIA grant number P30AG068635).
LA JOLLA—Salk scientists have used skin cells called fibroblasts from young and old patients to successfully create blood vessels cells that retain their molecular markers of age. The team’s approach, described in the journal eLife on September 8, 2020, revealed clues as to why blood vessels tend to become leaky and hardened with aging, and lets researchers identify new molecular targets to potentially slow aging in vascular cells.
LA JOLLA—Salk Institute scientists have made a major advance in the pursuit of a safe and effective treatment for type 1 diabetes, an illness that impacts an estimated 1.6 million Americans with a cost of $14.4 billion annually.
LA JOLLA—While your skeleton helps your body to move, fine skeleton-like filaments within your cells likewise help cellular structures to move. Now, Salk researchers have developed a new imaging method that lets them monitor a small subset of these filaments, called actin.
LA JOLLA—A drug candidate developed by Salk researchers, and previously shown to slow aging in brain cells, successfully reversed memory loss in a mouse model of inherited Alzheimer’s disease. The new research, published online in July 2020 in the journal Redox Biology, also revealed that the drug, CMS121, works by changing how brain cells metabolize fatty molecules known as lipids.
LA JOLLA—If you want to reduce levels of inflammation throughout your body, delay the onset of age-related diseases and live longer—eat less food. That’s the conclusion of a new study by scientists from the US and China that provides the most detailed report to date of the cellular effects of a calorie-restricted diet in rats. While the benefits of caloric restriction have long been known, the new results show how this restriction can protect against aging in cellular pathways, as detailed in Cell on February 27, 2020.
LA JOLLA—Due to the modern tendency to postpone childbirth until later in life, a growing number of women are experiencing issues with infertility. Infertility likely stems from age-related decline of the ovaries, but the molecular mechanisms that lead to this decline have been unclear. Now, scientists from the U.S. and China have discovered, in unprecedented detail, how ovaries age in non-human primates. The findings, published in Cell on January 30, 2020, reveal several genes that could be used as biomarkers and point to therapeutic targets for diagnosing and treating female infertility and age-associated ovarian diseases, such as ovarian cancer, in humans.
LA JOLLA—People with osteoarthritis, or “wear and tear” arthritis, have limited treatment options: pain relievers or joint replacement surgery. Now, Salk researchers have discovered that a powerful combination of two experimental drugs reverses the cellular and molecular signs of osteoarthritis in rats as well as in isolated human cartilage cells. Their results were published in the journal Protein & Cell on January 16, 2020.
LA JOLLA—In mouse models of Alzheimer’s disease, the investigational drug candidates known as CMS121 and J147 improve memory and slow the degeneration of brain cells. Now, Salk researchers have shown how these compounds can also slow aging in healthy older mice, blocking the damage to brain cells that normally occurs during aging and restoring the levels of specific molecules to those seen in younger brains.
LA JOLLA—Metformin is the most commonly prescribed type 2 diabetes drug, yet scientists still do not fully know how it works to control blood sugar levels. In a collaborative effort, researchers from the Salk Institute, The Scripps Research Institute and Weill Cornell Medical College have used a novel technology to investigate why it functions so well. The findings, which identified a surprising number of biochemical “switches” for various cellular processes, could also explain why metformin has been shown to extend health span and life span in recent studies. The work was published in Cell Reports on December 3, 2019.
LA JOLLA—Little is known about the molecular and cellular events that occur during early embryonic development in primate species. Now, an internationally renowned team of scientists in China and the United States has created a method to allow primate embryos to grow in the laboratory longer than ever before, enabling the researchers to obtain molecular details of key developmental processes for the first time. This research, while done in nonhuman primate cells, can have direct implications for early human development.
LA JOLLA—Although graduating from school, a first job and marriage can be important events in life, some of the most significant events happen far earlier: in the first few days after a sperm fertilizes an egg and the cell begins to divide.
LA JOLLA—The ability to edit genes in living organisms offers the opportunity to treat a plethora of inherited diseases. However, many types of gene-editing tools are unable to target critical areas of DNA, and creating such a technology has been difficult as living tissue contains diverse types of cells.
LA JOLLA—Scientists once thought that neurons, or possibly heart cells, were the oldest cells in the body. Now, Salk Institute researchers have discovered that the mouse brain, liver and pancreas contain populations of cells and proteins with extremely long lifespans—some as old as neurons. The findings, demonstrating “age mosaicism,” were published in Cell Metabolism on June 6, 2019. The team’s methods could be applied to nearly any tissue in the body to provide valuable information about lifelong function of non-dividing cells and how cells lose control over the quality and integrity of proteins and important cell structures during aging.
LA JOLLA—Three Salk Institute faculty members have been promoted after the latest round of faculty reviews determined they are scientific leaders who have made original, innovative and notable contributions to biological research.
LA JOLLA—Aging is a leading risk factor for a number of debilitating conditions, including heart disease, cancer and Alzheimer’s disease, to name a few. This makes the need for anti-aging therapies all the more urgent. Now, Salk Institute researchers have developed a new gene therapy to help decelerate the aging process.
LA JOLLA—Doctors have long observed that biological age and chronological age are not always one and the same. A 55-year-old may exhibit many signs of old age and have numerous age-related diseases, whereas an 80-year-old may be healthy and robust. While diet, physical activity and other factors play a role, there are many contributors as to why and how some people age better than others. Those contributors remain poorly understood.
LA JOLLA—Old age is the greatest risk factor for many diseases, including Alzheimer’s disease (AD) and cancer. Geroprotectors are a recently identified class of anti-aging compounds. New Salk research has now identified a unique subclass of these compounds, dubbed geroneuroprotectors (GNPs), which are AD drug candidates and slow the aging process in mice.
LA JOLLA—A team of Salk Institute researchers led by President Rusty Gage has been awarded $19.2 million over eight years by the American Heart Association-Allen Initiative in Brain Health and Cognitive Impairment to investigate mechanisms underlying Alzheimer’s disease and aging-related cognitive decline and uncover new therapies. This bold venture will comprehensively analyze interactions between five areas key to brain health: proteins, genes, metabolism, inflammation and epigenetics.
LA JOLLA—Juan Carlos Izpisua Belmonte, a professor in Salk’s Gene Expression Laboratory, has been named one of TIME magazine’s 50 most influential people in healthcare for his scientific innovations in addressing the shortage of human organs for transplant. The list, which is curated by TIME’s health reporters and editors, recognizes people who changed the state of healthcare in America this year, and bear watching for what they do next.
LA JOLLA—When we’re born, our brains have a great deal of flexibility. Having this flexibility to grow and change gives the immature brain the ability to adapt to new experiences and organize its interconnecting web of neural circuits. As we age, this quality, called "plasticity," lessens.
LA JOLLA—Plastic surgery to treat large cutaneous ulcers, including those seen in people with severe burns, bedsores or chronic diseases such as diabetes, may someday be a thing of the past. Scientists at the Salk Institute have developed a technique to directly convert the cells in an open wound into new skin cells. The approach relies on reprogramming the cells to a stem-cell-like state and could be useful for healing skin damage, countering the effects of aging and helping us to better understand skin cancer.
LA JOLLA—We’ve all heard the expression: “what doesn’t kill you makes you stronger.” Now, research led by a Salk Institute scientist suggests why, at a cellular level, this might be true. The team reports that brief exposures to stressors can be beneficial by prompting the cell to trigger sustained production of antioxidants, molecules that help get rid of toxic cellular buildup related to normal metabolism.
LA JOLLA—Defective energy production in old neurons might explain why our brains are so prone to age-related diseases. Salk researchers used a new method to discover that cells from older individuals had impaired mitochondria—the power stations of cells—and reduced energy production. A better understanding of the effects of aging on mitochondria could reveal more about the link between mitochondrial dysfunction and age-related brain diseases, such as Alzheimer's and Parkinson's.
LA JOLLA—For most people with hemophilia B, whose bodies can’t properly form blood clots, constant injections to replenish their clotting factors are a way of life. But now, Salk researchers have demonstrated in mice that hemophilia B can be treated for life with one single injection containing disease-free liver cells that can produce their missing clotting factor. The finding, published in the journal Cell Reports on May 1, 2018, could drastically change what it means to be diagnosed with hemophilia B, and could pave the way toward similar treatments for other, related genetic disorders.
LA JOLLA—Potentially explaining why even healthy brains don’t function well with age, Salk researchers have discovered that genes that are switched on early in brain development to sever connections between neurons as the brain fine-tunes, are again activated in aging neuronal support cells called astrocytes. The work, which appeared in Cell Reports on January 2, 2018, suggests that astrocytes may be good therapeutic targets to prevent or reverse the effects of normal aging.
LA JOLLA—The experimental drug J147 is something of a modern elixir of life; it’s been shown to treat Alzheimer’s disease and reverse aging in mice and is almost ready for clinical trials in humans. Now, Salk scientists have solved the puzzle of what, exactly, J147 does. In a paper published January 7, 2018, in the journal Aging Cell, they report that the drug binds to a protein found in mitochondria, the energy-generating powerhouses of cells. In turn, they showed, it makes aging cells, mice and flies appear more youthful.
LA JOLLA—Like an actor who excels at both comedy and drama, proteins also can play multiple roles. Uncovering these varied talents can teach researchers more about the inner workings of cells. It also can yield new discoveries about evolution and how proteins have been conserved across species over hundreds of millions of years.
LA JOLLA—The process by which embryonic stem cells develop into heart cells is a complex process involving the precisely timed activation of several molecular pathways and at least 200 genes. Now, Salk Institute scientists have found a simpler way to go from stem cells to heart cells that involves turning off a single gene.
LA JOLLA—In the bustling setting of the cell, proteins encounter each other by the thousands. Despite the hubbub, each one manages to selectively interact with just the right partners, thanks to specific contact regions on its surface that are still far more mysterious than might be expected, given decades of research into protein structure and function.
LA JOLLA—Every day, websites you visit and smartphone apps that you use are crunching huge sets of data to find things that resemble each other: products that are similar to your past purchases; songs that are similar to tunes you’ve liked; faces that are similar to people you’ve identified in photos. All these tasks are known as similarity searches, and the ability to perform these massive matching games well—and fast—has been an ongoing challenge for computer scientists.
LA JOLLA—It may seem paradoxical, but studying what goes wrong in rare diseases can provide useful insights into normal health. Researchers probing the premature aging disorder Hutchinson-Gilford progeria have uncovered an errant protein process in the disease that could help healthy people as well as progeria sufferers live longer.
LA JOLLA—Scientists have, for the first time, corrected a disease-causing mutation in early stage human embryos with gene editing. The technique, which uses the CRISPR-Cas9 system, corrected the mutation for a heart condition at the earliest stage of embryonic development so that the defect would not be passed on to future generations.
LA JOLLA—(May 4, 2017) Salk Institute scientists have developed a novel technology to correct disease-causing aberrations in the chemical tags on DNA that affect how genes are expressed. These types of chemical modifications, collectively referred to as epigenetics or the epigenome, are increasingly being considered as important as the genomic sequence itself in development and disease.
LA JOLLA—The Salk Institute has received a $3 million award from the Glenn Foundation for Medical Research for the second time in 4 years, enabling the Institute to continue investigating the biology of normal human aging and age-related diseases.
LA JOLLA—When scientists talk about laboratory stem cells being totipotent or pluripotent, they mean that the cells have the potential, like an embryo, to develop into any type of tissue in the body. What totipotent stem cells can do that pluripotent ones can’t do, however, is develop into tissues that support the embryo, like the placenta. These are called extra-embryonic tissues, and are vital in development and healthy growth.
LA JOLLA—Rapid advances in the ability to grow cells, tissues and organs of one species within an organism of a different species offer an unprecedented opportunity for tackling longstanding scientific mysteries and addressing pressing human health problems, particularly the need for transplantable organs and tissues.
LA JOLLA—Graying hair, crow’s feet, an injury that’s taking longer to heal than when we were 20—faced with the unmistakable signs of aging, most of us have had a least one fantasy of turning back time. Now, scientists at the Salk Institute have found that intermittent expression of genes normally associated with an embryonic state can reverse the hallmarks of old age.
LA JOLLA—Ever since researchers connected the shortening of telomeres—the protective structures on the ends of chromosomes—to aging and disease, the race has been on to understand the factors that govern telomere length. Now, scientists at the Salk Institute have found that a balance of elongation and trimming in stem cells results in telomeres that are, as Goldilocks would say, not too short and not too long, but just right.
LA JOLLA—Salk Institute researchers have discovered a holy grail of gene editing—the ability to, for the first time, insert DNA at a target location into the non-dividing cells that make up the majority of adult organs and tissues. The technique, which the team showed was able to partially restore visual responses in blind rodents, will open new avenues for basic research and a variety of treatments, such as for retinal, heart and neurological diseases.
LA JOLLA—We put things into a container to keep them organized and safe. In cells, the nucleus has a similar role: keeping DNA protected and intact within an enveloping membrane. But a new study by Salk Institute scientists, detailed in the November 2 issue of Genes & Development, reveals that this cellular container acts on its contents to influence gene expression.
LA JOLLA—Boosting levels of a specific protein in the brain alleviates hallmark features of Alzheimer’s disease in a mouse model of the disorder, according to new research published online August 25, 2016 in Scientific Reports.
LA JOLLA—For decades, scientists have known that people with two copies of a gene called apolipoprotein E4 (ApoE4) are much more likely to have Alzheimer’s disease at age 65 than the rest of the population. Now, researchers at the Salk Institute have identified a new connection between ApoE4 and protein build-up associated with Alzheimer’s that provides a possible biochemical explanation for how extra ApoE4 causes the disease.
LA JOLLA—Salk scientists and colleagues have proposed new molecular criteria for judging just how close any line of laboratory-generated stem cells comes to mimicking embryonic cells seen in the very earliest stages of human development, known as naïve stem cells. The tests found that no current protocols lead to truly naïve stem cells, but the guidelines may help researchers achieve that goal by pointing out where each current method falls short. Generating naïve stem cells would be a boon to both basic research and to medical applications of stem cells, such as growing tissue for organ replacement.
LA JOLLA—Chronic damage to the liver eventually creates a wound that never heals. This condition, called fibrosis, gradually replaces normal liver cells—which detoxify the food and liquid we consume—with more and more scar tissue until the organ no longer works.
LA JOLLA–Salk Institute researchers have found that an experimental drug candidate aimed at combating Alzheimer’s disease has a host of unexpected anti-aging effects in animals.
LA JOLLA–Healthy brain, muscle, eye and heart cells would improve the lives of tens of thousands of people around the world with debilitating mitochondrial diseases. Now, researchers at the Salk Institute have gotten one step closer to making such cures a reality: they’ve turned cells from patients into healthy, mutation-free stem cells that can then become any cell type. The new approach is described July 15, 2015 in Nature.
LA JOLLA–Bread, cereal and other sugary processed foods cause rapid spikes and subsequent crashes in blood sugar. In contrast, diets made up of vegetables, fruits and whole grains are healthier, in part because they take longer to digest and keep us more even-keeled.
LA JOLLA–Scientists at the Salk Institute have discovered a novel type of pluripotent stem cell–cells capable of developing into any type of tissue–whose identity is tied to their location in a developing embryo. This contrasts with stem cells traditionally used in scientific study, which are characterized by their time-related stage of development.
LA JOLLA–A study tying the aging process to the deterioration of tightly packaged bundles of cellular DNA could lead to methods of preventing and treating age-related diseases such as cancer, diabetes and Alzheimer’s disease, as detailed April 30, 2015, in Science.
LA JOLLA–Stem cells, which have the potential to turn into any kind of cell, offer the tantalizing possibility of generating new tissues for organ replacements, stroke victims and patients of many other diseases. Now, scientists at the Salk Institute have uncovered details about stem cell growth that could help improve regenerative therapies.
LA JOLLA–Just as some people seem built to run marathons and have an easier time going for miles without tiring, others are born with a knack for memorizing things, from times tables to trivia facts. These two skills–running and memorizing–are not so different as it turns out.
LA JOLLA–Researchers at the Salk Institute have healed injured hearts of living mice by reactivating long dormant molecular machinery found in the animals’ cells, a finding that could help pave the way to new therapies for heart disorders in humans.
LA JOLLA–Scientists at the Salk Institute have discovered an on-and-off “switch” in cells that may hold the key to healthy aging. This switch points to a way to encourage healthy cells to keep dividing and generating, for example, new lung or liver tissue, even in old age.
LA JOLLA—For the first time, scientists have turned human skin cells into transplantable white blood cells, soldiers of the immune system that fight infections and invaders. The work, done at the Salk Institute, could let researchers create therapies that introduce into the body new white blood cells capable of attacking diseased or cancerous cells or augmenting immune responses against other disorders.
LA JOLLA—Frogs, dogs, whales, snails can all do it, but humans and primates can’t. Regrow nerves after an injury, that is—while many animals have this ability, humans don’t. But new research from the Salk Institute suggests that a small molecule may be able to convince damaged nerves to grow and effectively rewire circuits. Such a feat could eventually lead to therapies for the thousands of Americans with severe spinal cord injuries and paralysis.
LA JOLLA—For hundreds of years, healers in São Tomé e Príncipe—an island off the western coast of Africa—have prescribed cata-manginga leaves and bark to their patients. These pickings from the Voacanga africana tree are said to decrease inflammation and ease the symptoms of mental disorders.
LA JOLLA—Researchers around the world have turned to stem cells, which have the potential to develop into any cell type in the body, for potential regenerative and disease therapeutics.
LA JOLLA—The Salk Institute has received a $3 million gift from the Glenn Foundation for Medical Research to allow the Institute to continue conducting research to understand the biology of normal human aging and age-related diseases.
LA JOLLA—Using reprogrammed skin cells, researchers have for the first time used stem cell techniques to grow fully functional assemblies of the cells that line airways leading to the lungs. The lab-grown airway tissue can now be used to study the molecular basis for lung diseases—from rare genetic disorders to common afflictions like asthma and emphysema—and test new drugs to treat the diseases.
LA JOLLA, CA—Diseases affecting the kidneys represent a major and unsolved health issue worldwide. The kidneys rarely recover function once they are damaged by disease, highlighting the urgent need for better knowledge of kidney development and physiology.
LA JOLLA, CA—Alzheimer’s disease affects more than 26 million people worldwide. It is predicted to skyrocket as boomers age—nearly 106 million people are projected to have the disease by 2050. Fortunately, scientists are making progress towards therapies. A collaboration among several research entities, including the Salk Institute and the Sanford-Burnham Medical Research Institute, has defined a key mechanism behind the disease’s progress, giving hope that a newly modified Alzheimer’s drug will be effective.
LA JOLLA, CA—Proteins are the chief actors in cells, carrying out the duties specified by information encoded in our genes. Most proteins live only two days or less, ensuring that those damaged by inevitable chemical modifications are replaced with new functional copies.
LA JOLLA, CA—Stem cells are key to the promise of regenerative medicine: the repair or replacement of injured tissues with custom grown substitutes. Essential to this process are induced pluripotent stem cells (iPSCs), which can be created from a patient’s own tissues, thus eliminating the risk of immune rejection. However, Shinya Yamanaka’s formula for iPSCs, for which he was awarded last year’s Nobel Prize, uses a strict recipe that allows for limited variations in human cells, restricting their full potential for clinical application.
LA JOLLA,CA—A team of scientists at the Salk Institute for Biological Studies has identified why disruption of a vital pathway in cell cycle control leads to the proliferation of cancer cells. Their findings on telomeres, the stretches of DNA at the ends of chromosomes that protect our genetic code and make it possible for cells to divide, suggest a potential target for preventive measures against cancer, aging and other diseases. The findings were published July 11, 2013 in Molecular Cell.
LA JOLLA,CA—Changes in the epigenome, including chemical modifications of DNA, can act as an extra layer of information in the genome, and are thought to play a role in learning and memory, as well as in age-related cognitive decline. The results of a new study by scientists at the Salk Institute for Biological Studies show that the landscape of DNA methylation, a particular type of epigenomic modification, is highly dynamic in brain cells during the transition from birth to adulthood, helping to understand how information in the genomes of cells in the brain is controlled from fetal development to adulthood. The brain is much more complex than all other organs in the body and this discovery opens the door to a deeper understanding of how the intricate patterns of connectivity in the brain are formed.
LA JOLLA, CA—A drug developed by scientists at the Salk Institute for Biological Studies, known as J147, reverses memory deficits and slows Alzheimer’s disease in aged mice following short-term treatment. The findings, published May 14 in the journal Alzheimer’s Research and Therapy, may pave the way to a new treatment for Alzheimer’s disease in humans.
LA JOLLA, CA—Scientists have long known that control mechanisms known collectively as “epigenetics” play a critical role in human development, but they did not know precisely how alterations in this extra layer of biochemical instructions in DNA contribute to development.
LA JOLLA, CA—For humans to grow and to replace and heal damaged tissues, the body’s cells must continually reproduce, a process known as “cell division,” by which one cell becomes two, two become four, and so on. A key question of biomedical research is how chromosomes, which are duplicated during cell division so that each daughter cell receives an exact copy of a person’s genome, are arranged during this process.
LA JOLLA, CA—A new method for generating stem cells from mature cells promises to boost stem cell production in the laboratory, helping to remove a barrier to regenerative medicine therapies that would replace damaged or unhealthy body tissues.
LA JOLLA, CA—Growing evidence suggests that there may be a link between diabetes and Alzheimer’s disease, but the physiological mechanisms by which diabetes impacts brain function and cognition are not fully understood. In a new study published in Aging Cell, researchers at the Salk Institute for Biological Studies show, for the first time, that diabetes enhances the development of aging features that may underlie early pathological events in Alzheimer’s.
LA JOLLA, CA—By reprogramming skin cells from Parkinson’s disease patients with a known genetic mutation, researchers at the Salk Institute for Biological Studies have identified damage to neural stem cells as a powerful player in the disease. The findings, reported online October 17, 2013 in Nature, may lead to new ways to diagnose and treat the disease.
LA JOLLA, CA—Based on two new studies by researchers at the Salk Institute for Biological Studies, regeneration of a new limb or organ in a human will be much more difficult than the mad scientist and supervillain, Dr. Curt Connors, made it seem in the Amazing Spider-man comics and films.
LA JOLLA, CA—Salk scientists have identified a unique molecular signature in induced pluripotent stem cells (iPSCs), “reprogrammed” cells that show great promise in regenerative medicine thanks to their ability to generate a range of body tissues.
LA JOLLA, CA—The Salk Institute is pleased to announce that professors E.J. Chichilnisky, Jan Karlseder, and Kuo-Fen Lee have each been selected as the recipient of an endowed chair to honor their consistent scientific excellence and support their biological research.
LA JOLLA, CA—With their potential to treat a wide range of diseases and uncover fundamental processes that lead to those diseases, embryonic stem (ES) cells hold great promise for biomedical science. A number of hurdles, both scientific and non-scientific, however, have precluded scientists from reaching the holy grail of using these special cells to treat heart disease, diabetes, Alzheimer’s and other diseases.
LA JOLLA, CA—Stem cells are essential building blocks for all organisms, from plants to humans. They can divide and renew themselves throughout life, differentiating into the specialized tissues needed during development, as well as cells necessary to repair adult tissue.
LA JOLLA, CA—One of the big mysteries in biology is why cells age. Now scientists at the Salk Institute for Biological Studies report that they have discovered a weakness in a component of brain cells that may explain how the aging process occurs in the brain.
LA JOLLA, CA—Scientists at the Salk Institute for Biological Studies have identified a gene that tells cells to develop multiple cilia, tiny hair-like structures that move fluids through the lungs and brain. The finding may help scientists generate new therapies that use stem cells to replace damaged tissues in the lung and other organs.
LA JOLLA, CA—A new drug candidate may be the first capable of halting the devastating mental decline of Alzheimer’s disease, based on the findings of a study published in PLoS ONE.
LA JOLLA, CA—Researchers at the Salk Institute for Biological Studies have developed a way to use patients’ own cells to potentially cure sickle cell disease and many other disorders caused by mutations in a gene that helps produce blood hemoglobin.
LA JOLLA, CA—An international team of scientists has created super-strong, high-endurance mice and worms by suppressing a natural muscle-growth inhibitor, suggesting treatments for age-related or genetics-related muscle degeneration are within reach.
LA JOLLA, CA—The Salk Institute is pleased to announce the appointment of five faculty members to be recipients of endowed chairs established by philanthropic leaders in support of scientific research.
LA JOLLA, CA—One of the few reliable ways to extend an organism’s lifespan, be it a fruit fly or a mouse, is to restrict calorie intake. Now, a new study in fruit flies is helping to explain why such minimal diets are linked to longevity and offering clues to the effects of aging on stem cell behavior.