USC Davis Faculty and Student Researchers Present at GSA Meeting

More than 50 USC Leonard Davis School of Gerontology faculty members and students presented research at the 2014 Gerontological Society of America (GSA) Annual Scientific Meeting held November 5-9 at the Walter E. Washington Convention Center in Washington, D.C. From poster presentations to awards, all facets of the school’s impressive scientific investigations were on display.

One of the highlights of the conference for the Davis School came when Assistant Professor Sean Curran received the 2014 Nathan Shock New Investigator Award. The Shock award, named after a gerontology research pioneer and GSA founding member, is a distinguished honor given for outstanding contributions and discoveries in basic aging biology research. Curran’s research focuses on identifying mechanisms that regulate survival and longevity in cells and organisms and understanding the roles that metabolism plays in both healthy aging and age-related illnesses.

“This is an incredible honor, and I am thankful to the GSA for this recognition,” Curran said.

The Davis School’s role in the meeting included heavy participation from both faculty and students sharing their research on a wide variety of subjects. Morgan Levine, a PhD student in Gerontology, chaired and gave a talk during the Human Genetics of Aging and Longevity Symposium, which discussed how the availability of large genetic data sets gives investigators the power to better research the role genes and gene-environment interactions play in aging.

During the symposium, Levine presented “The Whole Is Greater Than the Sum of Its Parts: Using Network Analysis to Identify Longevity Genes,” which examined unique models for longevity and stress resistance: people who have lived into their 80s despite being smokers. After mapping the genes of 90 such older smokers and 730 younger smokers, an analysis pinpointed a network of gene variants possibly playing a role in the older smokers’ longevity. The network was assembled into a polygenic risk score (PRS); further examination showed that this PRS was significantly associated with both increased lifespan and lower cancer odds in non-smokers.

“The next steps are to examine longevity gene networks using more sophisticated statistics-based approaches, including hierarchical clustering algorithms and weighted gene co-expression networks, which look for genes associated with multiple age-related conditions,” Levine said.

PhD student Nick Woodward was one of many Davis School students who presented research posters. During the Biological Sciences poster session, he discussed “Sexual Dimorphism in Neuroinflammation from Inhaled Particulate Matter in Older Mice,” which showcased the sex- and age-related differences in inflamed brain tissue in mice who had been repeatedly exposed to nano-scale particulate matter (nPM) air pollution. Brain inflammation was measured by the presence of the protein GFAP.

After the animals inhaled nPM—particles small enough to possibly enter the brain through the bloodstream—young male mice showed an increase in brain inflammation, while young female mice did not. Older mice of both sexes were found to have existing levels of brain inflammation even before inhaling the pollution, which caused a plateau in inflammatory responses. The older males had no additional immune response to the pollution, while the older females experienced a slight increase in inflammation in the corpus callosum portion of their brains.

“This is just the embryo of what I want to do,” Woodward explained, adding that he hopes to learn more about the consequences of neuroinflammation, especially since humans are heavily exposed to this kind of pollution from vehicle exhaust. Such exposure could be causing chronic inflammation in human brains, and “there might be additive effects,” he said.

As one of many Davis School faculty members discussing their work, USC Leonard Davis Hanson Family Trust Associate Professor of Gerontology Susan Enguídanos gave a talk during the Epidemiology of Frailty, Disease Burden, and Late-Life Care: Insights for Health Care and Policy Symposium. Based on collaborative research with Assistant Professor Jennifer Ailshire, “Exploring the Goldilocks Phenomenon for Completing Advance Directives: Does Early Completion Matter?” discussed the role of timing in the creation of advance directives and its relationship to patients’ care preferences.

Surprisingly, Enguídanos and Ailshire found that patients who developed advance directives during the last three months of their lives were more likely to prefer aggressive care compared to patients who developed directives further in advance of their deaths.

“Some have hypothesized that individuals developing advance directives very early—years before death—may be more likely to elect aggressive measures that would be reflective of their healthier condition,” Enguídanos said. “We did not find this in our study. Rates of aggressive care preference were quite low and pretty consistent up until the last three months of life.”

Enguídanos said she hopes to next examine whether care preferences themselves directly influence when patients create advance directives.

“Are those developing advance directives early those that prefer less aggressive care, and are those developing advance directives late or not at all reflective of those who prefer more aggressive measures?” she said. “Is there a selection bias in who develops advance directives?”

USC University Professor and AARP Professor of Gerontology Eileen Crimmins spoke during a symposium on the history of the National Institute on Aging titled “From Cells to Society: NIA at 40 – Past, Present, and Future.” Her talk, “Forty Years of Progress in the Behavioral and Social Sciences at NIA,” discussed social science research regarding health outcomes and aging, its evolution over the last 40 years, and its increasingly close-knit relationship with big data as well as with aging biology research.

While the scientific and medical communities have made great progress in keeping up with disabling consequences and halting the progression of existing disease, the conversation has only recently turned to preventing the onset of disease, Crimmins said. With emerging fields, more multidisciplinary investigations, and a better understanding of the physical, biological, and social factors influencing individuals and communities, researchers can now paint a clearer picture of how health behaviors are shaped and how they affect various health outcomes.

“We have not changed our basic questions. We still want to know why health changes with age and differs by social class, race, ethnicity, and gender, but we have changed the way we look at mechanisms and places to intervene,” Crimmins said. “We want to know how this is influenced by health behaviors, social support, health care usage, and personality and how social factors ‘get under the skin’ to change biology before the more downstream health changes related to aging.”

Along with sharing groundbreaking research throughout the week, students, faculty, alumni, and colleagues enjoyed a reception hosted by the Davis School on November 7 at the Washington Marriott Marquis Hotel.

To learn more about the dozens of USC Leonard Davis School posters and presentations, explore research abstracts from the meeting at http://gerontologist.oxfordjournals.org/content/54/Suppl_2/NP.1.full.pdf+html.