Exhaled Methyl Nitrate Levels Parallel Plasma Glucose in Diabetic Children

A study of children suffering from type I diabetes found that exhaled methyl nitrate levels measured with air-pollution testing techniques in the laboratory paralleled plasma glucose. This study could be the basis of a breath analysis test for non-invasive monitoring of glucose levels in diabetic children.

The scientists analyzed exhaled gas profiles and plasma glucose levels of 10 children with type I diabetes. Of a total of 18 experiments, five were done over periods of sustained euglycemia and 13 while hyperglycemia (160 to 410 mg/dl) was gradually corrected by intravenous insulin infusion. Air samples were analyzed in a laboratory with gas chromatography techniques used for air pollution testing, including electron capture, flame ionization, and mass selective detection.

Methyl nitrate levels were significantly elevated during hyperglycemia and fell as normal glucose levels were restored. The levels remained steady during periods of normal glucose levels. Among the more than 100 gases detected in the children's breath, methyl nitrate was most closely correlated with blood glucose levels.

The study, performed by Pietro R. Galassetti, M.D., Ph.D., from the University of California at Irvine (USA) and colleagues, was reported in the September 2007 online edition of the journal Proceedings of the [US] National Academy of Sciences (PNAS).

"The characteristics of methyl nitrate formation suggest that this gas may reflect, rather than hyperglycemia, per se, the specific and complex pattern of metabolic alteration accompanying hyperglycemia in type I diabetes mellitus,” the investigators wrote. "This includes not only hypoinsulinemia and increased lipids and ketones but also alterations in inflammatory and oxidative markers, now considered main determinants of diabetic vascular complications.”

Therefore, exhaled gas analysis for diabetic patients may also be useful in determining pathogenesis of complications, particularly because the method allows for testing of many different gases related to insulin, lipids, and other blood variables, Dr. Galassetti's group noted.


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