Quantitative image analysis of nailfold capillaries during an in-hospital education program for type 2 diabetes or obesity

Nailfold capillaries are small U-shaped vessels located beneath the skin at the proximal part of the fingernail, and their morphology changes owing to various diseases. This study quantitatively analyzed nailfold capillaries using microscopy in patients hospitalized for 2 weeks for education and treatment of type 2 diabetes (T2D) or obesity. Our results suggest that nailfold arterial diameter and smoking history are useful predictors of diabetic neuropathy. An elevated urinary albumin-to-creatinine ratio correlated with decreased venous diameter during hospitalization, reflecting latent intravascular hypoalbuminemia in patients with diabetic nephropathy. Both body mass index and short-term weight reduction during hospitalization correlated with the color contrast between the capillaries and the perivascular zone, defined as delta E. These results suggest that the morphology of nailfold capillaries in T2D and obesity could be useful indicators of diabetic neuropathy and nephropathy, with delta E being a useful indicator of extracellular water volume in these populations. This is the first study to observe short-term changes in nailfold capillary morphology in relation to interventions for lifestyle-related diseases.