MR details exercise-induced changes in fat distribution in diabetics

A six-month exercise regimen led to reduced visceral abdominal fat volume, decreased hepatic triglyceride content and lower paracardial fat volume among patients with diabetes, according to a study published online June 25 in Radiology.

Given the metabolic and cardiovascular benefits of exercise, physicians recommend patients with type 2 diabetes engage in 150 minutes of moderate exercise per week. Meanwhile, pericardial fat, myocardial triglyceride (TG) accumulation and hepatic steatosis are associated with cardiovascular complications.

Jacqueline T. Jonker, MD, from the department of endocrinology and metabolism at Leiden University Medical Center, in Leiden, the Netherlands, and colleagues hypothesized that an exercise-induced decrease in visceral abdominal fat would be accompanied by a decrease in epicardial fat. They designed a study leveraging MR imaging to evaluate these effects in patients with diabetes.

The researchers enrolled 12 patients, average age 46 years, who underwent MRI examinations before and after six months of moderate-intensity exercise totaling between 3.5 and six hours per week and featuring two endurance and two resistance training sessions. The exercise cycle culminated with a 12-day trekking expedition.

The exercise regimen produced a greater than 20 percent drop in several parameters, including visceral fat, hepatic TG content and paracardial fat.

“Visceral abdominal fat volume significantly decreased from 348 mL +/- 57 at the start of training to 219 mL +/- 33 at 220 days at the start of training,” wrote Jonker et al. Although subcutaneous abdominal fat volume remained unchanged, the ratio between the measures dropped from 0.53 +/- 0.11 to 0.34 +/- 0.06.

Paracardial fat volume dropped from 4.6 mL +/- 0.9 to 3.7 mL +/- 0.8 mL in 11 patients. Hepatic TG decreased from 6.8 percent +/- 2.3 at baseline to 4.6 percent +/- 1.6 after the expedition, reported Jonker et al.

The lack of impact of exercise on epicardial fat volume may not represent a problem, according to the researchers. “Recent studies have shown that paracardial fat volume is a better predictor of cardiovascular risk than epicardial fat, and therefore a decrease in paracardial fat might indicate a decreased cardiovascular risk.”

Jonker and colleagues acknowledged that the small number of patients in the study was a limitation. However, they emphasized the statistically significant changes in fat distribution with exercise.

The researchers expect to continue to utilize imaging to help define treatment for patients with diabetes. “In the future, we hope to be able to use advanced imaging techniques to predict in individual patients which therapeutic strategy is most effective: diet, medication, exercise, surgery or certain combinations,” Hildo J. Lamb, MD, PhD, senior author and also from Leiden University Medical Center, said in a release.