Diabetes Slows Nerve Recovery After Heart Transplant

"Using positron emission tomography [PET] and the transplanted heart as a very specific model to study the regenerative capacity of the heart's sympathetic nervous system, we determined that reinnervation--or the heart's ability to develop new nerves to replace damaged ones--is slower in diabetic patients,” said Dr. Frank M. Bengel, a visiting associate professor of radiology and the director of cardiovascular nuclear medicine from the department of radiology and radiologic science at Johns Hopkins Medicine (Baltimore, MD, USA) and co-author of the study, which was published in the September 2006 issue of the Journal of Nuclear Medicine. "Our results confirm a detrimental effect of diabetes on the potential for recovery of sympathetic nerve fibers of the heart.”

"A better understanding of the importance of nervous system abnormalities and an imaging technique to precisely characterize nerve damage may be of value to guide future therapeutic efforts aimed at reducing cardiac risk with diabetes mellitus patients,” explained Dr. Bengel, who was an associate professor at the Technical University of Munich (Germany), where the study was performed, prior to his move to Johns Hopkins. "Even if a transplant recipient is suffering from diabetes, there is still a chance for reinnervation--just at a slower speed. Unfortunately, there are no techniques developed yet that speed the nerve-regeneration process,” he said.

At present, nuclear medicine modalities (such as PET) are the only imaging techniques that can measure the presence and function of the sympathetic nervous system of the heart, according to Dr. Bengel. "There are invasive methods that allow for the measurement of neurotransmitters released to the blood, offering indirect conclusions about the presence, storage, and release of neurotransmitters from neurons. These methods require complicated and laborious sampling of blood from coronary arteries and veins,” he added.

Future studies will be needed to determined how regeneration of sympathetic nerves can be facilitated and how changes of the sympathetic nerve integrity in the heart are interrelated with changes of prognosis and outcome of diseases like diabetes mellitus, according to Dr. Bengel.



Related Links:
Johns Hopkins Medicine