Our Major Research Interests
Eating disorders and their metabolic consequences, including obesity and associated comorbidities, are the epidemics of the 21st century. Our group works hard to prevent, diagnose, and treat associated disease states, to understand the mechanisms underlying these disorders, and to consequently develop rational novel diagnostic and therapeutic tools for these conditions. More specifically, our main focuses are:
- Obesity and its consequences, including diabetes, cardiovascular disease, and malignancies
- Energy deficiency syndromes such as anorexia nervosa and hypothalamic amenorrhea
- Nutrition and metabolism
Basic Research Studies
Our basic research studies focus on physiological and pathophysiological regulation of novel molecules important in energy homeostasis, diabetes, and obesity, as well as complications of the latter including cardiovascular disease and malignancies. We utilize a wide range of research methods including genomics-bioinformatics, molecular biology, and animal physiology studies to answer important questions regarding obesity, insulin resistance, and their consequences which include diabetes, cardiovascular disease, and malignancies. Our ultimate goal is to develop novel diagnostic and therapeutic strategies by better-understanding and exploiting underlying mechanisms. Our main focuses are:
- Molecular pathogenesis of obesity, insulin resistance, and associated comorbidities, including cancer, cardiovascular disease, insulin resistance and type 2 diabetes
- Molecular biology, physiology, and pathophysiology of adipokines in animals and humans
- Molecular biology, physiology, and pathophysiology of myokines, such as irisin, in animals and humans.
We conduct and participate in large-scale epidemiological investigations, including cross-sectional, cohort, and case control studies, in collaboration with members of the Environmental Health, Nutrition, and Epidemiology Departments of the Harvard School of Public Health as well as the Veterans Administration healthcare system.
Our research efforts have expanded to studying non-modifiable disease determinants, including certain single nucleotide polymorphisms, as well as modifiable determinants, such as diet and exercise, as predictors of adipokine concentrations and/or metabolic diseases.
Following our initial work on the role of insulin and insulin-like growth factors, we performed the first case-control and prospective cohort studies demonstrating that adiponectin is a key link between obesity/insulin resistance and common malignancies associated with obesity including endometrial, breast, prostate, renal, and colon cancers. Ongoing studies are investigating the underlying mechanisms and exploring the roles of adiponectin and other adipokines as diagnostic and therapeutic agents in these disease states.
The above basic research and epidemiologic studies have provided important new information and have advanced our knowledge of human physiology and pathophysiology. The hope is that these advances will ultimately lead to therapeutic breakthroughs.
Our main focuses are:
- Nutritional determinants of hormones, diabetes, and cardiovascular disease.
- Clinical epidemiology studies in the areas of diabetes, cardiovascular disease, and malignancies.
- Developing new diagnostic and therapeutic tools for the above disease states.
To understand the neuropharmacology underlying leanness and obesity, we utilize functional magnetic resonance imaging and neurocognitive testing. Our recent studies have illuminated the functional brain activation changes to food cues in response to leptin administration in lean, hypoleptinemic women. Studies examining the effects of other molecules or medications which treat obesity are underway. Furthermore, we are also examining how receptors for key molecules regulating energy homeostasis are expressed in the human brain using immunohistochemistry. Through the combination of these techniques, we will be better able to understand the mechanisms of action for these molecules and be better able to help develop future, successful therapeutics.
Clinical Interventional Studies
Our interventional studies in humans range from early phase pharmacokinetic and small scale, investigator-initiated "proof of concept" studies, to medium, and large-scale double blind placebo-controlled clinical trials, which, if positive, are later expanded into multi-center clinical trials.
Our group was the first to complete pharmacokinetic studies of leptin in humans and were the first to conclusively demonstrate, utilizing "proof of concept" studies involving leptin administration, the role of leptin in regulating the neuroendocrine response to energy deprivation in humans. We were also the first to demonstrate that low leptin levels are intimately linked with neuroendocrine abnormalities observed in the "female triad" (a disease state characterized by the simultaneous presentation of disordered eating, amenorrhea, and decreased bone mineral density) or in anorexia nervosa. Further, we demonstrated that administration of leptin, in replacement doses, corrects neuroendocrine and reproductive abnormalities and improves markers of bone density in strenuously exercising women athletes with the "female triad". Leptin was recently approved by the FDA for treatment of lipodystrophy in humans.
Currently, we are further exploring the role of leptin in the physiology, pathophysiology, and potential treatment of several disease states, including obesity.
Examples of our current studies are presented in the
Our work, funded by the NIH, the ADA, HMS, Foundations, and the Pharmaceutical Industry, has resulted in over 500 original publications in medicine, more than 135 collaborative papers in the context of the Look AHEAD Study, over 150 reviews/chapters in textbooks, and over 25,000 citations with an H-index of more than 85. Group members have been honored with prestigious awards at National/International meetings.