Microvascular abnormalities in pediatric diabetic patients

Microvascular abnormalities are associated with and causative of the development of end-stage organ complications in adult diabetic patients. Whether the same microvascular abnormalities are present in pediatric patients is not known and has not been studied because of a lack of real-time technology, methodology to study young patients, and availability of an appropriate noninvasive site for in vivo studies. We hypothesized that microvascular abnormalities should be present in pediatric patients despite their young age and the relatively short durations of the disease. In this study, computer-assisted intravital microscopy (CAIM) was adapted to blindly quantify microvascular abnormalities in 12 pediatric type 1 diabetic mellitus (T1DM) patients (ages = 6-16 years; mean +/- SD = 11.42 +/- 3.42; duration since diagnosis = 2-14 years; mean +/- SD = 6.75 +/- 3.79) in vivo, using the microcirculation of the bulbar conjunctiva as a noninvasive site. Microvascular abnormalities, commonly found in adult patients, existed in the conjunctival microcirculation of all pediatric T1DM patients in varying degrees despite their relatively young age. A severity index (SI) was developed to reflect the cumulative severity of the microvascular abnormalities and was computed as the summation of all microvascular abnormalities found in each patient. SI for the 12 T1DM patients (mean +/- SD = 7.42 +/- 1.88; median = 8; mode = 9) differed significantly from that for the nondiabetic controls (mean +/- SD = 0.67 +/- 0.78; median = 0.5; mode = 0; P < 0.0001). In addition, SI correlated with hemoglobin A1c levels (mean +/- SD = 9.18 +/- 1.57) of T1DM patients but did not correlate with the duration of disease since diagnosis of the same patients. This observation raises the possibility that diabetic pathogenesis may precede the onset of overt disease or clinical diagnosis. This study confirms that CAIM may represent the availability of a useful real-time technology to study conjunctival microvascular abnormalities in vascular diseases in juvenile as well as adult patients.