Purpose: Diabetes mellitus-induced erectile dysfunction (ED) in men is a worldwide problem. Histopathological changes in diabetic corpora cavernosa (CC) tissue are not fully understood due to limited studies on human tissues. The aim of this study was to compare histopathological changes between CC of diabetic and nondiabetic patients with ED.
Patients and methods: Forty CC biopsies were taken from 16 diabetic and 24 nondiabetic men during penile implant insertion. Formalin-fixed paraffin-embedded sections from each specimen were stained with conventional hematoxylin and eosin stains for general assessment of histopathological changes, with Masson trichrome for assessment of smooth muscle (SM) fibers and collagen, and with Verhoeff’s elastic van Gieson stain for assessment of elastic fibers (EF). SM fibers were assessed for cell thickness/bundle, shape, and percentage from trabecular tissue thickness. EF were assessed for shape and percentage from trabecular tissue. Arteries and venous sinuses were assessed for presence of subendothelial fibrosis. The main outcome measures were thickness and shape of trabecular SM bundles, percentage of trabecular EF and shape, and presence of subendothelial fibrosis.
Results: No difference in SM thickness was detected; however, SM in the diabetic group showed higher degree of shape abnormality in the form of frayed fibers (P=0.007) and more intramuscular fibrosis (P=0.001). The percentage of collagen fibers was significantly higher in diabetic patients (P=0.002). The percentage of EF in trabecular tissue ranged from 10 to 60% and was significantly reduced in diabetic patients (P=0.015). Subendothelial fibrosis within arteries and sinuses was higher in the diabetic group (P=0.059 and 0.002, respectively).
Conclusion: The major structural changes within CC tissue in diabetic patients were fraying and fibrosis in SM, increased trabecular collagen fibers, and reduction of EF. These changes may play a role in prevention of SM relaxation and interference