Can insulin injections delay or prevent the onset of type 1 diabetes in high-risk groups? Metabolism magazine reports that Rodriguez-Villar, Conget, et al at the Endocrinology Unit in Barcelona, Spain, investigated this possibility by giving insulin injections to people at risk of developing type 1. The theory behind this practice is that injecting insulin keeps the immune system from recognizing and attacking beta cells and their product, insulin.
A person considered at high risk was a first-degree relative, with positive islet cell antibodies and diminished first-phase insulin secretion.
Four high-risk individuals and a control group of four healthy people recieved insulin shots to induce beta-cell rest without any hypoglycemic risk.
First, the subjects were hospitalized. They then received three NPH insulin shots of .1 U x kg body weight, .2 U x kg body weight, and .3 U x kg body weight per day in a single dose on four consecutive days.
Researchers then measured how much C-peptide was in the urine and also took 24-hour serum profiles for glucose before and after the insulin shots.
After insulin, at the dose of .1 U x kg body weight, a significant inhibition of insulin produced and secreted by the body was observed in high risk subjects, but not in the control subjects. Interestingly, no further inhibition was observed with higher insulin doses.
Outpatient therapy continued after the experiment in the hospital for the high-risk subjects. Their sustained beta-cell rest was measured after 3, 6 and 12 months of treatment with insulin at .1 U x kg body weight per day. With this dose, no subject developed hypoglycemia, but hypoglycemia was detected after injections of .2 and .3 U x kg body weight in both groups.
The results of the study indicate giving NPH insulin at .1 U x kg body weight per day induces beta-call rest without the dangerous result of hypoglycemic episodes.