Columbus, OH - May 2016
Cardiovascular complications are a major cause of death for patients with Type 1 diabetes mellitus (T1DM), and an early marker of cardiovascular disease is endothelial dysfunction resulting from oxidative damage. Antioxidant vitamins C and E have been shown in animal models and some adult studies to reduce oxidation of the endothelium.
Endocrinologists at Nationwide Children’s Hospital hoped to find that the vitamins would also reduce oxidative damage in adolescents with T1DM, since T1DM-associated atherosclerosis can begin at a relatively young age.
“We were disappointed,” says Robert Hoffman, MD, a member of the Section of Endocrinology at Nationwide Children’s and senior author of a study examining the hypothesis. “But some other studies with these vitamins haven’t always worked as well as we thought when we studied patients instead of animal models.”
The study, published in the Journal of Diabetes Research, enrolled nine patients with T1DM, ranging from ages 8 to 15. The patients took daily combined vitamin C and E supplementation for six weeks based on body weight:
The doses were based on those used previously in adult studies, and were designed to be therapeutic while avoiding potential risks, according to Dr. Hoffman.
No differences before and after therapy were seen in endothelial function as measured by forearm vascular resistance to occlusion. There were also no differences in total plasma antioxidant capacity, high-sensitivity C-reactive protein, endothelial progenitor cell percentage and adiponectin.
With this result, it makes sense to step back and focus more on the mechanisms of endothelial dysfunction in patients with T1DM, says Dr. Hoffman, who is also a professor of Pediatrics at The Ohio State University College of Medicine.
“We can assume that endothelial dysfunction will happen for these patients over time, and it’s often the first marker of cardiovascular disease later on,” he explains. “If we’re hoping to prevent the disease in patients with and without Type 1 diabetes, we need to find out how endothelial dysfunction develops.”
Cazeau RM, Huang H, Bauer JA, Hoffman RP. Effect of vitamins C and E on endothelial function in Type 1 diabetes mellitus. Journal of Diabetes Research. 2015 Dec 10 [Epub ahead of print]