Glycosylated proteins of skin, nail and hair: application as an index for long-term control of diabetes mellitus.

The purpose of the present study was to compare the degrees of nonenzymatically glycosylated proteins in the skin (stratum corneum), the nail, the hair, and hemoglobin obtained simultaneously from the same subject and to evaluate the most useful sample for management of diabetic complications. Fifty-one diabetic patients and 20 control patients were examined, utilizing furosine determination. Furosine value of the skin in diabetics was 2.14 +/- 1.70%, whereas that in controls was 1.65 +/- 0.47%. Furosine value of the nail in diabetics was 6.67 +/- 3.30%, whereas that in controls was 4.16 +/- 1.62%. Furosine value of the hair in diabetics was 1.30 +/- 1.11%, whereas that in controls was 1.29 +/- 1.71%. Close correlations were detected between HbA1 (glycosylated hemoglobin) and furosine of the nail (r = 0.58, p less than 0.001), HbA1 and furosine of the skin (r = 0.48, p less than 0.001), and HbA1 and furosine of the hair (r = 0.43, p less than 0.01); however, poor correlations were found between furosine of the hair and the skin (r = 0.35, p less than 0.05) and furosine of the nail and the hair (r = 0.33, p less than 0.05). Furosine of the nail was significantly correlated with the FBS (fasting blood sugar) of the same time, previous 6, and previous 12 months. Furosine value of the nail, we believe, is the most useful indicator for evaluating long term control of diabetics and may provide useful information for management of diabetic complications.