Proinsulin-expressing dendritic cells in type 2 neuropathic diabetic patients with and without foot lesions

Diabetic neuropathy is the most common complication of diabetes and is frequently associated with foot ischemia and infection, but its pathogenesis is controversial. We hypothesized that proinsulin expression in peripheral blood mononuclear cells is a process relevant to this condition and could represent a link among hyperglycemia, nerve susceptibility, and diabetic foot lesions. We assessed proinsulin expression by using flow cytometry in dendritic cells from control participants and patients with type 2 diabetes with or without peripheral neuropathy or accompanied by diabetic foot. Among 32 non-neuropathic and 120 neuropathic patients with type 2 diabetes, we performed leg electromyography and found average sensory sural nerve conduction velocities of 48 ± 4 and 30 ± 4 m/s, respectively (P < 0.03). Of those with neuropathy, 42 were without lesions, 39 had foot lesions, and 39 had neuroischemic foot lesions (allux oximetry <30 mmHg). In this well-defined diabetic population, but not in nondiabetic parti...