Comparative analysis of the penis corpora cavernosa in controls and patients with erectile dysfunction

OBJECTIVE To evaluate the presence of structural disorders of the corpora cavernosa in patients with erectile dysfunction (ED), as despite new drugs being effective in many men with ED, some aspects of structural disorders of the corpora cavernosa remain unknown. MATERIALS AND METHODS Biopsy specimens were taken from the corpora cavernosa of seven patients (mean age 57.8 years, range 51–72) with severe ED who had a penile prosthesis implanted. The controls tissues were fragments of corpora cavernosa obtained from autopsies of six men (mean age 52.3 years, range 40–66) who died from causes unrelated to the urogenital system. For light microscopy, the specimens were processed routinely to paraffin wax, and by immunohistochemistry to evaluate elastic fibres, and by Masson's trichrome to analyse collagen and smooth muscle fibres. Stereological methods were used to quantitatively evaluate the different elements (as a percentage). RESULTS The percentages of the different elements in the human penis of controls and men with ED, respectively, were: elastic fibres 13.2% and 9.1%; collagen fibres 40.8% and 41.6%; and smooth muscle, 40.4% and 42%. CONCLUSIONS In patients with ED there was a statistically significant reduction in the percentage of elastic fibres, but no statistically significant difference in collagen and smooth muscle fibres, and no appreciable differences in collagen distribution between the groups.