A computer-assisted intravital microscopy technology has been developed to noninvasively and objectively study diabetic microangiopathy in the conjunctival microcirculation of type-1 diabetics. Quantitative characterization of the conjunctival microcirculation was performed on 12 patients pre- and 18 months postsimultaneous pancreas-kidney transplantation (SPK). Healthy nondiabetic volunteers (n=12), solitary kidney (K) transplanted type-1 diabetics (n=5), and nontransplanted type-1 diabetics (n=12) served as controls. Pre-SPK diabetics showed abnormal-sized venules (diameter=66±7 μm) and reduced presence of arterioles (arteriole length/area=18±6 μm-1) compared with nondiabetic controls (53±4 μm; 31±8 μm-1; P<0.05). The computed vascular perfusion capacity of the conjunctival microvasculature was diminished in the same patients (pre-SPK diabetics=49±9%; nondiabetic healthy controls=71±6%; P<0.05). Significant improvement in microangiopathy was observed in all post-SPK diabetics (diameter=58±6 μm; arteriole length/area=26±9 μm-1; vascular perfusion=63±8%; P<0.05) 18 months post-SPK. Blood flow velocities in the conjunctival microcirculation in the same post-SPK patients showed noticeable but not significant improvements (nondiabetic controls=2.94±0.57 mm/sec; pre-SPK= 1.23±0.49 mm/sec; post-SPK=1.65±0.42 mm/sec). The solitary kidney transplant controls (post-K) showed no significant improvements in diabetic microangiopathy, confirming the unique role of the pancreas in SPK. In general, significant improvements (P<0.05) in diabetic microangiopathy were observed in all 12 diabetics 18 months post-SPK but not in the controls.
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