MedicalResearch.com Interview with:
Ifat Levy, PhD
Associate Professor
Comparative Med and Neuroscience
Yale School of Medicine
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: The proportion of older adults in the population is rapidly rising. These older adults need to make many important decisions, including medical and financial ones, and therefore understanding age-related changes in decision making is of high importance. Prior research has shown that older adults tend to be more risk averse than their younger counterparts when making choices between sure gains and lotteries. For example, asked to choose between receiving $5 for sure and playing a lottery with 50% of gaining $12 (but also 50% of gaining nothing), older adults are more likely than young adults to prefer the safe $5. We were interested in understanding the neurobiological mechanisms that are involved in these age-related shifts in preferences.
An earlier study that we have conducted in young adults provided a clue. In that study, we measured the risk preference of each participant (based on a series of choices they made between safe and risky options), and also used MRI to obtain a 3D image of their brain. Comparing the behavioral and anatomical measures, we found an association between individual risk preferences and the gray-matter volume of a particular brain area, known as “right posterior parietal cortex” (rPPC), which is located at the back of the right side of the brain. Participants with more gray matter in that brain area were, on average, more tolerant of risk (or less risk averse).
This suggested a very interesting possibility – that perhaps the increase in risk aversion observed in older adults is linked to the thinning of gray matter which is also observed in elders. In the current study we set out to test this hypothesis, by measuring risk preference and gray matter density in a group of 52 participants between the ages of 18 and 88. We found that, as expected, older participants were more risk averse than younger ones, and also had less gray matter in their rPPC. We also replicated our previous finding - that less gray matter was associated with higher risk aversion. The critical finding, however, was that
the gray matter volume was a better predictor of increased risk aversion than age itself. Essentially, if both age and the gray matter volume of rPPC were used in the same statistical model, rPPC volume predicted risk preferences, while age did not. Moreover, the predictive power was specific to the rPPC – when we added the total gray matter volume to the model, it did not show such predictive power.
Dr. Liu[/caption]
Leyuan Liu, Ph.D., Assistant Professor
Center for Translational Cancer Research
Institute of Biosciences and Technology
Texas A&M University
Houston, Texas 77030
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Our research team has been working on the question why people develop cancers and how we can prevent or cure them. In contrast to public views, we concluded from our studies that cancers, similar to our age-related diseases, originate from inefficiencies of our body to clean up cellular wastes accumulated during our lifespan. The most important pathway to clean up those wastes is called autophagy, or cellular self-eating behavior. We study how autophagy is regulated, how autophagy causes cancers, and whether we can control autophagy to prevent or cure cancers.
Previously we found autophagy is regulated by a protein called MAP1S and mice without MAP1S are more likely to develop liver cancer. We have been seeking ways to improve MAP1S-mediated autophagy to prevent liver cancer. Our current study show that spermidine, a natural component existing in many foods, can increase the stability of MAP1S proteins and activate MAP1S-mediated autophagy. Concurrent with the benefits of expand mouse lifespans ours also reported, spermidine can suppress the development of liver fibrosis and liver cancer specifically through MAP1S if we add spermidine into the daily drinking water of mice.
Dr. David Sebastián[/caption]
MedicalResearch.com Interview with:
Dr. David Sebastián
IRB Barcelona and CIBERDEM researcher
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: One of the alterations that most affects the quality of life of the elderly is muscle wastage and the resulting loss of strength, a condition known as sarcopenia. At about 55 years old, people begin to lose muscle mass, this loss continues into old age, at which point it becomes critical. However, the underlying causes of sarcopenia are unknown and thus no treatment is available for this condition.
Importantly, we have found that the mitochondrial protein Mitofusin 2 is required to preserve healthy muscles in mice. Mitofusin 2 is a mitochondrial protein involved in ensuring the correct function of mitochondria, and it has several activities related to autophagy, a crucial process for the removal of damaged mitochondria. The loss of Mitofusin 2 impedes the correct function of mitochondrial recycling and consequently damaged mitochondria accumulate in muscle cells.
Dr. Kathleen Fischer[/caption]
Kathleen Fischer, PhD
Department of Biology
UAB | University of Alabama Birmingham
Birmingham, AL
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Fischer: Aging is by far the greatest risk factor for most of the chronic, non-communicable diseases (e.g. cardiovascular disease, cancer, diabetes). By discovering the basic mechanisms responsible for aging we can find ways to extend healthy and productive life and reduce the burdens of chronic disease and disability experienced by individuals and society. Sex differences in longevity can provide novel insights into the basic biology of aging; however this aspect of aging has been largely ignored.
Demographic data show that women outlive men in every society during every historical period and in every geographic area. In spite of this robust survival advantage, women suffer far greater morbidity late in life—a phenomenon described as the morbidity-mortality paradox. It is not clear whether this is a general mammalian pattern or something unique to humans. Research on sex differences in aging and age-related diseases in humans and a range of species will be crucial if we are going to identify the basic mechanisms responsible for the patterns we observe.
Dr. Jennifer Lemon[/caption]
Jennifer Lemon, PhD
Research Associate
Medical Radiation Sciences
McMaster University
MedicalResearch.com: What is the background for this study?
Dr. Lemon: Research with the supplement began in 2000, as part of my doctoral degree; we developed the supplement to try to offset the severe cognitive deterioration and accelerated aging in a mouse model we were working with in the lab. Based on aging research, five mechanisms appeared to be key contributors to the process of aging; those include oxidative stress, inflammation, mitochondrial deterioration, membrane dysfunction and impaired glucose metabolism. The criteria we used for including components in the supplement were as follows: each one of the 30 components had scientific evidence to show they acted on one or more of the above mechanisms were able to be taken orally, and were available to humans over-the-counter. Even then the hope was that if the formulation was successful, this would make it more available to the general public.
Dr. Jill Cameron[/caption]
Jill Cameron, PhD
Canadian Institutes of Health Research New Investigator
Associate Professor,
Department of Occupational Science and Occupational Therapy
Rehabilitation Sciences Institute
Faculty of Medicine,
University of Toronto
MedicalResearch.com: What is the background for this study? What are the main findings?
Dr. Cameron: In the world of critical illness, a lot of research has focused on helping people to survive – and now that more people are surviving, we need to ask ourselves, what does quality of life and wellbeing look like afterwards for both patients and caregivers? The aim of our research was to identify factors associated with family caregiver health and wellbeing during the first year after patients were discharged from the Intensive Care Unit. We examined factors related to the patient and their functional wellbeing, the caregiving situation including the impact it has on caregivers everyday lives, and caregiver including their sense of control over their lives and available social support. We used Pearlin’s Caregiving Stress Process model to guide this research.
From 2007-2014, caregivers of patients who received seven or more days of mechanical ventilation in an ICU across 10 Canadian university-affiliated hospitals were given self-administered questionnaires to assess caregiver and patient characteristics, caregiver depression symptoms, psychological wellbeing, and health-related quality of life. Assessments occurred seven days and three, six and 12-months after ICU discharge.
The study found that most caregivers reported high levels of depression symptoms, which commonly persisted up to one year and did not improve in some. Caregiver sense of control, impact on caregivers’ everyday lives, and social support had the largest relationships with the outcomes. Caregivers’ experienced better health outcomes when they were older, caring for a spouse, had higher income, better social support, sense of control, and caregiving had less of a negative impact on their everyday lives. No patient characteristics or indicators of illness severity were associated with caregiver outcomes.
Poor caregiver outcomes may compromise patients’ rehabilitation potential and sustainability of home care. Identifying risk factors for caregiver distress is an important first step to prevent more suffering and allow ICU survivors and caregivers to regain active and fulfilling lives.