Muscle capillary basement membrane in juvenile diabetes mellitus

Calculations of the minimum rather than the average basement membrane thickness of muscle capillaries established that widening of this structure was only rarely encountered in juvenile-onset diabetes of 1–6 yr duration. The basement membrane was usually, but not always, thickened, however, in childhood-onset diabetes present for 7 or more yr. The presence or absence of basement membrane thickening did not appear to be related to age at onset of diabetes, the degree of hyperglycemia in an oral glucose tolerance test, any residual ability to secrete insulin, the type, dosage or schedule of insulin therapy, history of ketoacidosis and shocking, blood pressure, or the state of the kidneys. However, each of the patients with an increase in the width of the basement membrane of muscle capillaries did have microaneurysms. Our data are consonant with the hypothesis that thickening of the basement membrane generally appears toward the end of the first decade following the diagnosis. Since duration and age tend to be related, such thickening was more common in the older persons with juvenile-onset diabetes. Also, in such patients serum creatinine tended to be higher and proteinuria was more frequent, two variables known to be influenced by duration of diabetes and increased chronologic age.