Partial reversal of aging achieved in mice

first_imgHarvard scientists at Dana-Farber Cancer Institute say they have for the first time partially reversed age-related degeneration in mice, resulting in new growth of the brain and testes, improved fertility, and the return of a lost cognitive function.In a report posted online by the journal Nature in advance of print publication, researchers led by Ronald A. DePinho, a Harvard Medical School (HMS) professor of genetics, said they achieved the milestone in aging science by engineering mice with a controllable telomerase gene. The telomerase enzyme maintains the protective caps called telomeres that shield the ends of chromosomes.As humans age, low levels of telomerase are associated with progressive erosion of telomeres, which may then contribute to tissue degeneration and functional decline in the elderly. By creating mice with a telomerase switch, the researchers were able to generate prematurely aged mice. The switch allowed the scientists to find out whether reactivating telomerase in the animals would restore telomeres and mitigate the signs and symptoms of aging. The work showed a dramatic reversal of many aspects of aging, including reversal of brain disease and infertility.While human applications remain in the future, the strategy might one day be used to treat conditions such as rare genetic premature aging syndromes in which shortened telomeres play an important role, said DePinho, senior author of the report and the director of Dana-Farber’s Belfer Institute for Applied Cancer Science. “Whether this would impact on normal aging is a more difficult question,” he added. “But it is notable that telomere loss is associated with age-associated disorders and thus restoration of telomeres could alleviate such decline.” The first author is Mariela Jaskelioff, a research fellow in medicine in DePinho’s laboratory.Importantly, the animals showed no signs of developing cancer. This remains a concern because cancer cells turn on telomerase to make themselves virtually immortal. DePinho said the risk can be minimized by switching on telomerase only for a matter of days or weeks — which may be brief enough to avoid fueling hidden cancers or cause new ones to develop. Still, he observed, it is an important issue for further study.In addition, DePinho said these results may provide new avenues for regenerative medicine, because they suggest that quiescent adult stem cells in severely aged tissues remain viable and can be reactivated to repair tissue damage.“If you can remove the underlying damage and stresses that drive the aging process and cause stem cells to go into growth arrest, you may be able to recruit them back into a regenerative response to rejuvenate tissues and maintain health in the aged,” he said. Those stresses include the shortening of telomeres over time that causes cells and tissues to fail.Loss of telomeres sends a cascade of signals that cause cells to stop dividing or self-destruct, stem cells to go into retirement, organs to atrophy, and brain cells to die. Generally, the shortening of telomeres in normal tissues shows a steady decline, except in the case of cancer, where they are maintained.The experiments used mice that had been engineered to develop severe DNA and tissue damage as a result of abnormal, premature aging. These animals had short, dysfunctional telomeres and suffered a variety of age-related afflictions that progressed in successive generations of mice. Among the conditions were testes reduced in size and depleted of sperm, atrophied spleens, damage to the intestines, and shrinkage of the brain along with an inability to grow new brain cells.“We wanted to know: If you could flip the telomerase switch on and restore telomeres in animals with entrenched age-related disease, what would happen?” explained DePinho. “Would it slow down aging, stabilize it, or even reverse it?”Rather than supply the rodents with supplemental telomerase, the scientists devised a way to switch on the animals’ own dormant telomerase gene, known as TERT. They engineered the endogenous TERT gene to encode a fusion protein of TERT and the estrogen receptor. This fusion protein would only become activated with a special form of estrogen. With this setup, scientists could give the mice an estrogen-like drug at any time to stimulate the TERT-estrogen receptor fusion protein and make it active to maintain telomeres.Against this backdrop, the researchers administered the estrogen drug to some of the mice via a time-release pellet inserted under the skin. Other animals, the controls, were given a pellet containing no active drug.After four weeks, the scientists observed remarkable signs of rejuvenation in the treated mice. Overall, the mice exhibited increased levels of telomerase and lengthened telomeres, biological changes indicative of cells returning to a growth state with reversal of tissue degeneration, and increase in size of the spleen, testes, and brain. “It was akin to a Ponce de León effect,” noted DePinho, referring to the Spanish explorer who sought the mythical Fountain of Youth.“When we flipped the telomerase switch on and looked a month later, the brains had largely returned to normal,” said DePinho. More newborn nerve cells were observed, and the fatty myelin sheaths around nerve cells — which had become thinned in the aged animals — increased in diameter. In addition, the increase in telomerase revitalized slumbering brain stem cells so they could produce new neurons.To show that all this new activity actually caused functional improvements, the scientists tested the mice’s ability to avoid a certain area where they detected unpleasant odors that they associated with danger, such as scents of predators or rotten food. They had lost that survival skill as their olfactory nerve cells atrophied, but after the telomerase boost, those nerves regenerated and the mice regained their crucial sense of smell.“One of the most amazing changes was in the animals’ testes, which were essentially barren as aging caused the death and elimination of sperm cells,” recounted DePinho. “When we restored telomerase, the testes produced new sperm cells, and the animals’ fecundity was improved — their mates gave birth to larger litters.”The telomerase boost also lengthened the rodents’ life spans compared to their untreated counterparts — but they did not live longer than normal mice, said the researchers.The authors concluded, “This unprecedented reversal of age-related decline in the central nervous system and other organs vital to adult mammalian health justifies exploration of telomere rejuvenation strategies for age-associated diseases.”Other authors include members of the DePinho research group and Eleftheria Maratos-Flier, an HMS professor of medicine at Beth Israel Deaconess Medical Center.The research was supported by grants from the National Institutes of Health and the Belfer Foundation.last_img read more

TLC for Nursery Plants

first_imgColquitt County tree grower Melton Mercer said he likes this benefit — he doesn’t have to stakehis young trees. And he pointed out yet another plus: pot-in-pot trees and shrubs use less waterand fertilizer. A University of Georgia researcher, though, has found how to give these plants that tender, lovingcare. He puts them back in the ground. The pot-in-pot system offers several advantages over traditional single-pot, aboveground nurseryoperations. You expect nursery residents to get a lot of loving care. But many trees grown in nurseries have atough time trying to thrive in aboveground pots until they’re transplanted into the ground. The system uses two black plastic pots — the kind nursery plants are commonly grown in.Growers set one, called the holder pot, in the ground, then plant the tree or shrub in the secondpot and place it into the first. Using the pot-in-pot system costs nursery operators three to four times as much to set up asaboveground systems. But Ruter said most can recover their costs in about four years in twoways: water and fertilizer savings and better space use. With the pot-in-pot system, growers canraise up to 3,000 more plants in a 10-acre plot. The second pot and surrounding soil insulates the plant’s roots from heat — especially importantfor Georgia nurseries. In traditional potting systems, Ruter has measured soil temperatures above130 degrees in the summer. “And in the end,” Ruter said, “they’ll have more and healthier plants for their customers.” Another advantage of the underground pot system is stability. Ruter said top-heavy abovegroundpots can blow over easily in even light winds. “This system keeps the pots upright, even in heavywinds,” he said.center_img “(Consumers) are getting a healthier plant, a plant that grows faster and has a better root system,”he said. “It’s not uncommon to get a 30 percent to 40 percent increase in root growth comparedto a plant grown aboveground.” John Ruter, a research horticulturist with the UGA College of Agricultural and EnvironmentalSciences, has found that a second pot provides something of a security blanket for young treesand shrubs. It protects their roots from both heat and cold. Ruter agrees. In many cases, the cooler summertime soil around the pot keeps water fromevaporating quickly. When the soil temperature doesn’t reach extreme highs, the plant grows more actively and usesfertilizer more efficiently, growing healthier. “It takes a lot less water than it would with overhead irrigation,” Mercer said. “On the south and west sides of the containers, there will be almost no roots viable for a couple ofinches in,” he said. The heat from the sun can literally cook tender young roots. Ruter said the pot-in-pot system helps nursery producers grow healthier, more vigorous landscapeplants.last_img read more

Grad students and ’SC officials discuss key issues

first_imgGraduate Student Government held its first town hall meeting Wednesday night, where students got the chance to interact with a panel of university officials who answered questions concerning graduate students.Panelists · Vice Provost for Graduate Programs Sally Pratt and Vice President for Student Affairs Michael Jackson respond to questions about graduate students’ needs. – Priyanka Patel | Daily TrojanPanelists included Dept. of Public Safety Chief Carey Drayton, Senior Associate Dean of Students Lynette Merriman, Vice Provost for Graduate Programs Sally Pratt and Vice President for Student Affairs Michael Jackson.The 20 graduate students who attended the meeting discussed issues ranging from security to financial aid with the panelists.Drayton emphasized that the department’s primary goal is to ensure the safety of university students. He said he supported the new policies that make the University Park Campus a closed campus between 9 p.m. and 6 a.m., following the shooting incident on campus last week.“We’re not building walls, but we’re putting things in a different sort of light than we have before,” Drayton said. “So things change and coming through campus is one thing that is going to change.”Current national issues affecting university policies were also discussed, particularly the Supreme Court case of Fisher v. University of Texas, regarding a college’s right to use affirmative action with decisions regarding student admittance.Jackson defended the university’s policy of holistic review, stating he personally benefited from affirmative action.“USC’s committed to providing access to folks who historically might have been denied access to an institution like USC,” Jackson said. “We want other students of color to have access to these schools.”Recognizing that this diversity at the university creates a wide range of graduate students to support, all of the representatives present on the panel stressed they were advocates for students pursuing their master’s degrees.“My job is making sure USC is a welcoming environment that allows students to flourish, and we are responsible to both undergraduate and graduate student needs,” Jackson said.Pratt recognized the difference between addressing undergraduate and graduate students, and assured town hall members that the university has resources for graduate students.“Undergraduate students are most like each other,” Pratt said. “However, graduate students are very focused on a given set of things. All graduate studies are hard and are built on stress. I’m interested in working with all constituents to find out what graduate students’ needs [are].”Tiffany De Leon Avalos, a first year graduate student in the Rossier School of Education, believes town halls help build connections among graduate students while creating an outlet to address shared concerns.“Because graduate school is complex and we all are focused on our own studies, these meetings give us the opportunity to foster a community and feel that there is an agency advocating for us,” De Leon Avalos said.The Graduate Student Government hopes to continue connecting graduate students across diverse fields together throughout the year. Graduate Student Government has planned several social and professional events for graduate students to foster this sense of community.“We are the voice of and advocate for students, especially since graduate students are very internally focused,” said GSG President Yael Adef, a graduate student in the USC School of Social Work. “We want to break down any barriers that may exist.”last_img read more

Head of Camogie Ass says Tipp’s future is bright

first_imgThat’s the view of Camogie Association President Catherine Neary, who made her comments at the recent launch of Feile na nGael 2016.Tipp’s minor face Galway in the All-Ireland Final replay on Saturday while the county’s seniors just missed out on a place in this weekend’s National League Final.Catherine Neary says sides representing Tipperary are in the mix for honours…last_img