Michael Massett, Ph.D.
Assistant Professor
Low exercise capacity or cardiorespiratory fitness is comparable to elevated systolic blood pressure, obesity, diabetes, and smoking as a risk factor and predictor of future disease. However, there is a high degree of individual variation in cardiorespiratory fitness before and after exercise training, including individuals that may not respond at all to training. Non-responding individuals might not benefit from increased physical activity and may be at higher risk for diseases related to low fitness, such as cardiovascular disease, metabolic syndrome, and breast and colon cancer. The genetic factors determining the magnitude of the response to exercise are poorly understood. Therefore, the objective of this research is to use genetic/genomic approaches including quantitative trait loci (QTL) mapping to identify novel candidate genes that influence the variation in exercise training responses. Using QTL mapping, potential QTL for exercise-training responses have been identified on chromosomes 2, 12, and 14 (LOD 3.49 – 6.25). These data suggest that variation in the responses to exercise training (trainability) is affected by specific chromosomal regions and likely specific genes. Genetic and bioinformatics approaches will be used to identify and narrow QTL that affect variation in exercise training adaptations based on changes in exercise performance. Congenic strains of mice will be created to confirm and narrow the QTL intervals. Finally, candidate genes will be identified using microarray analysis. Overall, these experiments will provide insight into the genetic basis for individual differences in the responses to exercise training as well as identify novel candidate genes that determine these individual differences. Because improving cardiorespiratory fitness through exercise training can significantly reduce the risk of cardiovascular disease, metabolic syndrome, and breast and colon cancer, understanding the genetic factors associated with the variability in the adaptation to exercise training may help to elucidate the mechanistic basis for chronic diseases associated with low levels of fitness.
Steven E. Riechman, Ph.D., M.P.H.
Assistant Professor
The primary objective of this study is to have 36 men and women (age 50-69) perform 12 weeks of resistance exercise training for the purpose of inducing skeletal muscle hypertrophy. These individuals will consume either 0, 1, or 3 whole eggs per day in a double-blind design to test the hypothesis that dietary cholesterol is essential for skeletal muscle hypertrophy. If so proven, this will confirm a very strong association between dietary cholesterol and hypertrophy observed in a previous study of 51 men and women (age 60-69). The current proposal is using a randomized double-blind, placebo controlled design to provide the most conclusive evidence that dietary cholesterol plays an essential role in skeletal muscle hypertrophy. The secondary objective of this proposal is to test the hypothesis that increased dietary cholesterol consumption in the context of an exercise program does not alter blood cholesterol concentrations or cardiovascular risk.
Dr. John M. Lawler, Ph.D.
Associate Professor
Aging is characterized by a progressive reduction in contractility and maximal cardiac output along with an increased risk of morbidity and mortality from cardiovascular diseases. One critical factor that contributes to age-related decline in cardiac function is the loss of cardiac myocytes. Indeed, the typical 70 year old man will have a 30% reduction in the number of myocytes. This has important clinical relevance as the heart cannot easily replace lost cells. Myocytes may be lost through necrosis or programmed cell death termed “apoptosis.” A 200% increase in cell death with aging without signs of necrosis. Recent evidence also indicates elevated pro-apoptotic signaling in the aging heart. An important target of aging may be the mitochondrial Bcl-2 family (e.g., Bax, Bad, Bcl-2) pathway and caspase-3 activation. In contrast, endurance exercise training consistently improves cardiovascular function and reduces risk of morbidity and mortality from cardiovascular diseases. However, the mechanisms by which exercise training may spare loss of myocytes and cardiovascular function with increasing age are unknown. Our goal is to determine the mechanisms of exercise protection against pro-apoptotic signaling in the aging heart. Specifically, we will test the hypotheses that (a) exercise training will ameliorate age-induced increases mitochondrial Bcl-2-family driven apoptosis in the rat left ventricle and (b) exercise training will partially protect against doxorubicin-induced increases in apoptosis in the aging left ventricle. Four (young adult) and 24 month old (old) Fischer-344 rats will be divided into sedentary and exercise trained groups. Exercise training regiment will be 12 weeks long using uphill treadmill running. The left ventricle will be analyzed for Bcl-2 family, caspases, and DNA fragmentation/apoptosis using Western immunoblotting, ELISA techniques, and immunohistochemistry techniques. Mitochondrial respiration will also be assessed. We expect that exercise training will attenuate age-induced increases in apoptosis in the heart. We further expect that the results from our investigation will directly lead to new therapeutics combining exercise training with targeted pharmaceuticals that will relieve the decline in heart function by aging.
Sponsors: Texas Affiliate of the American Heart Association, Texas A&M Vice President's Office for Research.
Initial Publications and abstracts:
Kwak, H.-B., W. Song,, and J.M. Lawler. (2006). Exercise-training ameliorates age-induced elevation in Bcl-2 family pro-apoptotic signaling in the aging rat heart. The FASEB Journal. In Press.
Lawler, J.M., H.B. Kwak, and J.H. Kim. Twelve weeks of exercise training upregulates Mn-SOD while reducing iNOS and oxidative stress in the rat left ventricle. 2006 American College of Sports Medicine meeting, Denver, CO. Med. Sci Sports Exer. (abstract) In Press.
Kwak, H.B., W. Song., J.H. Kim, and J.M. Lawler. Responses of fas/cytokine-mediated apoptotic pathway to 12 weeks of treadmill training in the aging rat heart. Experimental Biology ‘06 meeting, FASEB J. In Press.
Kwak, H.B., W. Song, and J.M. Lawler. Exercise training ameliorates age-induced elevation of caspase-9, cleaved caspase-3, and apoptosis in the rat heart. Paper presented at the International Union of Physiological Sciences/Experimental Biology 2005 meeting in San Diego, CA. FASEB J. 19: A1569, 2005.
Dr. Christopher R. Woodman, Ph.D.
Assistant Professor
The general aim of this research project is to determine the interactive effects of aging and exercise on skeletal muscle vascular beds. The primary goal is to understand the mechanisms by which endothelial and vascular smooth muscle cells adapt to aging resulting in increased risk of developing cardiovascular disease. In addition, we study mechanisms by which exercise training attenuates or reverses the detrimental effects of aging on vascular cell function. Functional studies are conducted using isolated perfused arteries to determine the cell signaling events in endothelial and vascular smooth muscle cells that mediate endothelium dependent vasodilation. Biochemical and molecular techniques are used to determine mechanisms contributing to age-induced endothelial dysfunction and to determine mechanisms by which exercise training improves vascular cell function in senescent arteries.
Sponsors: National Institute on Aging
Selected Publications:
Woodman CR, Price EM, and Laughlin MH. Aging induces muscle specific impairment of endothelium-dependent dilation in skeletal muscle feed arteries. J Appl Physiol 93: 1685-1690, 2002.
Woodman CR, Price EM, and Laughlin MH. Aging impairs nitric oxide- and prostacyclin-mediation of endothelium-dependent dilation in soleus feed arteries. J Appl Physiol 95: 2164-2170, 2003.
Laughlin MH, Woodman CR, Schrage WG, Gute D, and Price EM. Interval sprint training enhances endothelial function in some arteries that perfuse white gastrocnemius muscle. J Appl Physiol 96: 233-244, 2004.
Woodman CR, Price EM, and Laughlin MH. Shear stress induces eNOS mRNA expression and improves endothelium-dependent dilation in senescent soleus feed arteries. J Appl Physiol 98: 940-946, 2005.
Dr. B.E. Pruitt, Dr. Patricia Goodson, along with doctoral students Sandy Suther and Kelly Wilson are wrapping up the second year of their evaluation of the abstinence-only-until-marriage programs in the state of Texas. These programs are designed to teach youth about the benefits of abstaining from sexual activity until marriage; they are funded by Title V federal grants to the states. During these two years, evaluation efforts have centered on implementation issues: the obstacles that these programs face, staff's perceptions of how/why these programs work, and how programs are managed on a daily basis. Recently, author Michael Erard interviewed Dr. Goodson and Dr. Pruitt about their evaluation. Erard's view of the evaluation process can be found at http://www.texasobserver.org/showArticle.asp?ArticleFileName=020412_d1.htm
Professor
This is a continuing set of experiments designed to explore the programming characteristics involved in limb selection and reaching movements. Our quest, from a developmental perspective, is to identify the specific aspects of cognitive and neuromotor processes used in action processing. These experiments use an imagined (compared to) actual movement paradigm. With this general design, we are able to examine the cognitive level of action processing.
This research project, being conducted by Dr. Carl Gabbard and Luis Rodrigues, has the intent to develop a unique observational research instrument to assess the quality and quantity of motor development affordances in the home for children birth to 3 years. The instrument has the potential for excellent research and applied value. Contemporary infant research suggests quite convincingly that an optimal level of development occurs only with a stimulating environment and strong contextual support. We anticipate that phase II will include children ages 3 to 6 years.
Principle Investigator: Dr. Ranjita Misra
This project focuses on the variations in acceptance of diabetes as a disease by adults of different ethnicities (Hispanics, African Americans, Asian Americans, and Caucasians) to manage Type 2 diabetes. Diabetes mellitus has reached epidemic proportions and is a significant public health problem. It is the sixth leading cause of death among adults, with the majority affected by Type 2 or Non-Insulin-Dependent Diabetes Mellitus (90-95% of diagnosed cases). Diabetes disproportionately affects minority populations, making it a major source of health disparity. The prevalence among minorities, i.e., African-Americans, Hispanics, and Asian Americans and Pacific Islander (API), is 2-6 times greater than that of the non-Hispanic white population (Hosey, Gordon, & Levine, 1998). While it is evident that diabetes self-management strategies will reduce their risk for severe complications and mortality, there is a paucity of research on ethnic variation in diabetes self-management. Further, patient acceptance of the disease, critical for compliance in self-management and lifestyle modifications, has rarely been researched. This grant is supported by Texas A&M University's College of Education and Human Development.
Dr. John S. Green, Philip R. Stanforth, Dr. Jacques Gagnon, Dr. Arthur S. Leon,
Dr. D. C. Rao, Dr. James S. Skinner, Dr. Claude Bouchard, Dr. Tuomo Rankinen,
and Dr. Jack H. Wilmore
Visceral fat obesity (obesity in which fat accumulation is predominantly in
the intraabdominal cavity) has been closely linked with disorders of both glucose
and lipid metabolism, thereby significantly contributing to atherosclerotic
heart disease risk. From clinical experiments, aging, physical inactivity,
and sex hormone imbalance have been suggested as being influential in the accumulation
of visceral fat. Contemporary studies investigating the possible role of menopause
and estrogen replacement in this scenario have shown no consensus. Some suggest
estrogen replacement reduces visceral fat deposition while others purport no
effect. The purpose of this ongoing investigation is to examine data from the
HERITAGE Family Study in an effort to determine if exercise, menopause, and
estrogen replacement therapy influence visceral adiposity in women. The HERITAGE
Family Study is a large multi-center clinical study exploring possible genetic
influences on physiological response variability and the changes in risk factors
for coronary disease and diabetes consequent to a regimen of endurance exercise.
Investigators: Dr. Ranjita Misra & Dr. T.G.Patel
Indian Americans are represented under the broader classification of Asian
Americans and Pacific Islanders (API). They represent the third largest Asian
subcategory, and one of the fastest growing immigrant groups in the United
States. However, they have been relatively neglected in terms of cardiovascular
and diabetes research. Asian Indian immigrants worldwide experience excess
mortality from coronary artery disease (CAD). Although mortality among Asian
Indians from chronic diseases is comparable to other minority population, case
fatality ratio from diabetes and CAD appears to be much higher. Studies that
look at APIs in the aggregate mask the nature and extent of disparities among
the subgroups (Japanese, Chinese, Korean, Indians, Vietnamese, etc).
The purpose of this pilot project is to (1) get baseline information on the
prevalence of diabetes and other chronic disease, risk factors for chronic
disease (especially diabetes and CAD), and health behaviors among Indian American
males and females, and (2) explore other co-morbid conditions in this population.
This grant is funded by Pfizer, and channeled through the American Association
of Physicians of Indian Origin (AAPI).
Dr. John S. Green, Wade Womack, Kari Meyer, Dr. Steve Crouse, Rose Schmitz,
Kirsten Brekken, Dr. Sandy Kimbrough
Research in the area of heart disease risk perception is not abundant. A paucity
of dated information suggests that adults often incorrectly perceive their
risk, leaning toward an optimistic bias. The few recent publications that could
be found indicate that heart disease risk perception may be related to an individual's
perception of their overall general health and whether or not they perceive
themselves susceptible to diseases other than heart disease. All of the studies
noted above, however, used adults as subjects and no studies could be found
describing heart disease risk perception in the young. Furthermore, to the
authors' knowledge, no studies exist that examine the possibility of a relationship
between an individual's perception of their risk and their actual risk as indicated
by the number and relative severity of known physiological risk markers (serum
lipids, blood pressure, body composition, etc.) The purpose of this ongoing
study, therefore, is to quantify heart disease risk perception in college students
and determine if a relationship exists between perceived and actual heart disease
risk.
Investigators: Dr. Ranjita Misra & Dr. Danny Ballard
The intent of this pilot project is to incorporate community needs
assessment research into the undergraduate classroom as an active
learning project - one of the seven principles for good practice
in undergraduate education. With a growing emphasis on undergraduate
research and skills development, this project will take the students
through the process that health educators use to identify gaps
between current programs and required programs and place those
needs (gaps in results) in a priority order. Needs assessments
are useful to health educators primarily in planning programs and
promoting effective public relations. It also helps to identify
and diagnose health problems and in evaluating programs. Project
will encompass mastery in a wide spectrum of skills: Identifying
the sources of data (primary data - survey, nominal group process,
community forums, focus groups, and observation; secondary data
(government agencies, data available from health records, and current
literature) and gathering data from target audience, analyzing
the data collected, prioritizing the identified needs, as well
as abstracting information concisely. Inclusion of the proposed
project will help students identify need(s) to address community
health problems and concerns. This grant is supported by Texas
A&M University's Centers for Teaching Excellence Grant.
Investigators: Dr. Ranjita Misra, Padmini Balagopal, & Dr. N. Kamalamma
Diabetes disproportionately affects Indians, making it a major
source of health disparity. It is projected that 57.2 million individuals
will have diabetes by 2025. The majority of individuals with diabetes
are affected by Type 2, or Non-Insulin-Dependent Diabetes Mellitus
(90-95% of diagnosed cases). Several factors such as population
growth, genetic predisposition, high illiteracy rate, poverty,
and sociological changes that impact lifestyle behaviors have been
implicated in the etiology and increase of this disease in India.
The objectives of this research is to determine whether diabetes
education and prevention program is effective in reducing the incidence
and complications, and improve self-management strategies through
lifestyle changes in this rural population. The study design consists
of a quasi-experimental approach with ten villages - 5 villages
selected as the experimental site and 5 comparable villages as
controls from the catchment's area of Gandhigram University. The
sample will be comprised of a convenience group of 500 respondents
in both the experimental and control villages (300 adults, 100
premenopausal women of childbearing age, and 100 children). Face-to-face
interviews will be used as the data collection method. The intervention
will comprise of a multi-pronged education of the individuals and
families at various levels e.g., empowerment techniques, (e.g.,
self-help groups) and education programs (as part of the graduate/undergraduate
student's internship and coursework on in the department of Nutrition & Dietetics
through the University), to provide a continuity of this thrust
on an ongoing basis.
Investigators: Dr. Stephen F. Crouse, Dr. Mark English, Dr. Judy Delp, & Dr.
J. James Rohack
It is generally held that endurance training (ET) produces favorable
changes in lipid metabolism, thereby lowering coronary heart disease
(CHD) risk. While the mechanisms involved remain unclear, exercise-induced
changes in lipid enzyme activity may be partly responsible. Of
important clinical relevance, those with dyslipidemias, e.g., low
HDL-C with elevated TG (lipid triad), have seldom been studied.
Moreover, compared to the ET literature, there is a dearth of information
regarding the effects of resistance training (RT) on lipoprotein-lipids.
Reports are often contradictory, and information comparing the
effectiveness of RT to ET at equivalent caloric expenditure is
lacking. Published evidence shows that a significant portion of
the lipid benefit often attributed to ET may actually result from
short-term changes in lipid metabolism occurring acutely after
one exercise session. More research is needed to differentiate
the acute from the chronic effects of exercise training. At present,
it is not clear that resistance exercise will produce substantial
acute changes in lipids similar in magnitude to that of ET, and
the influence of RT on the acute response to resistance exercise
has not been studied. We are currently conducting a study in two
groups of men and women volunteers; Group 1 with low HDL-C combined
with elevated TG and Group 2 with both normal HDL-C and TG. Randomly
selected subjects will undergo either RT or ET for 16 wks; a control
group will not train. Before and after the training period we will
characterize the acute effects of exercise on lipid metabolism
by measuring the following variables before and after one session
of resistance or endurance exercise. The variables to be measured
are: TC, TG, HDL-C, HDL2&3-C, and LDL-C; apolipoproteins A-I
and B; LDL and HDL particle size; and lipoprotein lipase (LPLa)
and cholesterol ester transfer protein (CETPa) activity. We will
test the following hypotheses in this study: 1) ET and RT will
produce a less atherogenic lipid profile in those with low and
normal HDL-C; 2) LPLa will be increased and CETPa will be decreased
after 16 wks of RT and ET compared to the control group; 3) a single
session of RT and ET exercise will produce increases in the activities
of LPL and CETP that will result in lower TG and greater HDL-C
levels. This study will provide information to be applied toward
the optimization of primary and secondary prevention strategies
to reduce CHD risk.