Bariatric surgery yields new clues about obesity, diabetes and heart disease
Story Date: Tue, 04 Nov 2014 17:28:00 CST
Scientists examining fat tissue and blood samples collected before and after bariatric surgery are gleaning important information about how obesity, diabetes and heart disease are interrelated.
Bariatric surgery results in weight loss but also conveys many health advantages, like improved heart health and a reduced risk for diabetes, stroke and heart attack. EVMS scientists are working with surgeons at Sentara Comprehensive Weight Loss Solutions to uncover clues about what’s behind these dramatic improvements.
“We want to know what’s happening in the body following bariatric surgery,” says Jerry Nadler, MD, Chair of Internal Medicine, the Harry H. Mansbach Chair in Internal Medicine and Vice Dean for Research, who initiated the research. “That knowledge could lead to the development of medications or other treatment options that could have the same metabolic effects but without surgery.”
The collaborative research has focused on three distinctive areas: inflammation, blood clots and nerve pain.
The first study concentrated on a family of enzymes associated with inflammation called lipoxygenases that can contribute to the development of diabetes and heart disease. The team, led by Anca Dobrian, PhD, Associate Professor of Physiological Sciences, found high levels of a particular lipoxygenase enzyme in obese patients with diabetes.
“The pro-inflammatory product of this enzyme subtype correlated with other inflammatory markers that were selectively increased in the visceral (belly) fat of obese subjects with diabetes,” Dr. Dobrian says.
Visceral fat is associated with insulin resistance that can lead to Type 2 diabetes, says David Lieb, MD, Associate Professor of Internal Medicine and a clinician and researcher at the EVMS Strelitz Diabetes Center.
“Selective inhibition of the enzyme that was found elevated in diabetic subjects may help to limit the inflammation, insulin resistance and diabetes seen in obese people,” Dr. Lieb says.
That study is part of an NIH-funded project examining mechanisms underlying the inflammatory drivers in visceral fat. The research appears in Journal of Clinical Endocrinology and Metabolism.
The second study concentrated on blood platelets. When platelets become overactive — as they do in obese patients — they cling together and can cause a stroke or heart attack, says lead researcher Yulia Dobrydneva, PhD, Assistant Professor of Physiological Sciences.
Dr. Dobrydneva and her colleagues were surprised when they examined blood samples from patients who underwent gastric bypass surgery. They found that the overactive blood platelets subsided as early as one month after the procedure.
“I was shocked,” says Dr. Dobrydneva, who noticed the drop in platelet activity even before patients lost any significant weight. “I couldn’t believe what I was seeing.”
She theorizes that the effect results from a rapid improvement in the sensitivity of platelets to insulin. If confirmed, it could guide care for morbidly obese patients who are at high risk of stroke or heart attack. Her study is published in the journal Obesity Surgery.
Spearheading the final study was Aaron Vinik, MD, PhD, the Murray Waitzer Endowed Chair in Diabetes Research and Director of Research at the Strelitz Diabetes Center.
Overweight patients, particularly those with diabetes, suffer from heart problems and peripheral nerve damage. Dr. Vinik's research, presented at the national meeting of the American Diabetes Association, noted a marked improvement among bariatric surgery patients.
The surgery, he says, improves cardiac autonomic neuropathy and peripheral nerve function, drastically reducing risk of mortality from cardiovascular events.
So far the EVMS-Sentara collaboration has resulted in 10 scientific communications, published abstracts and papers.
“We are very supportive of collaborations like this with important health-care partners like Sentara Health System,” Dr. Nadler says.
Stephen Wohlgemuth, MD, (Resident ’86) and Mark Fontana, MD, of Sentara Comprehensive Weight Loss Solutions, are equally enthusiastic.
“As surgeons we have long been aware of the remarkable improvement in many comorbid conditions after bariatric surgery, particularly Type 2 diabetes mellitus,” says Dr. Woglemuth. “It’s very exciting to be a small part of this incredible team that is beginning to figure out what’s behind these improvements.”
In the photo above: Physicians and scientists involved in the bariatric research include, from left, Margaret Hatcher; Becky Marquez; B Bronson Haynes; Stephen Wohlgemuth, MD; David Lieb, MD; Norine Kuhn; Aaron Vinik, MD, PhD; Jerry Nadler, MD; Yulia Dobrydneva, PhD; Anca Dobrian, PhD; and Matt Butcher.