into the major pelvic ganglion (MPG); and nine had bilateral cavernosal nerve crush and injection of NES cells into the corpora cavernosa. Erectile response was assessed by cavernosal nerve electrostimulation at 3 months, and penile tissue samples were evaluated histochemically for nitric oxide synthase (NOS)-containing fibres, tyrosine hydroxylase and neurofilament staining. RESULTSThe groups injected with NES cells into the MPG and corpora cavernosa had significantly higher intracavernosal pressures than the control group. Immunohistochemical staining also revealed differences in the quality of the NOS-containing nerve fibres. Neurofilament staining was significantly better in the experimental groups injected with NES cells. CONCLUSIONWe were able to isolate embryonic stem cells that had differentiated along the neural cell line and, using these NES cells intracavernosally, showed improved erectile function in a rat model of neurogenic impotence.

The normal 3-dimensional structure of the tunica affords great flexibility, rigidity and tissue strength to the penis, which are lost consequent to structural changes in Peyronie's disease.

In patients who recover erectile function after radical prostatectomy (with preservation of at least 1 neurovascular bundle), a recovery time of 6 to 18 months is not uncommon. As this is also the usual time required for regeneration of spinal nerves, we believe that regeneration of cavernous nerves, partially damaged inadvertently, may be responsible. In a rat model, we examined the long-term effect of unilateral and bilateral cavernous nerve transection on the nonadrenergic/noncholinergic (NANC) nervous system and erectile function. In 31 rats, nitric oxide synthase (NOS), the enzyme that catalyzes nitric oxide production, was identified in penile nerve fibers from a mid-shaft segment with nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase staining and antibody to neuronal NOS. Animals were divided into three groups: 5 rats underwent pelvic exploration without transection of cavernous nerves (sham group); 13 rats underwent unilateral neurotomy of a 5-mm. segment of the cavernous nerve; and 13 rats underwent bilateral neurotomy. After bilateral ablation, the NOS-positive nerve fibers were significantly decreased at 3 weeks and remained so at 6 months; no erectile response could be elicited by pelvic nerve stimulation. After unilateral ablation, the NOS-positive nerve fibers were similarly decreased on the side of the neurotomy at 3 weeks, but by 6 months the number had increased significantly and approximated the level on the contralateral side. Furthermore, electrostimulation of the intact side induced a greater intracavernous pressure response at 6 months than at 3 weeks (N.B. the rat has an incomplete septum). Fibers positive for NOS were also identified in the dorsal nerve. The staining pattern diminished as rapidly and significantly on the side of neurotomy as in tissue from the corpus cavernosum. However, regeneration was not seen. To our knowledge, this is the first demonstration of regeneration of NOS-containing nerves after cavernous nerve neurotomy. Our findings support the reports by others that unilateral nerve-sparing is sufficient to preserve erectile function.

Objective  To investigate whether changes in the structure of the tunica albuginea influence the development of erectile dysfunction. Patients and methods  Biopsy specimens taken from the tunica of 64 patients (both potent and impotent) with and without Peyronie's disease were evaluated. Tissue samples were stained and examined under light and electron microscopy, and the concentration of elastic fibres present in each was measured using computerized image analysis. Results  The concentration of elastic fibres was lower in impotent than in potent patients (P=0.0365) and was also significantly less in patients with Peyronie's disease. Furthermore, the concentration of elastic fibres decreased with age. Electron and light microscopy revealed the presence of distinct alterations in the tunica albuginea in impotent patients and patients with Peyronie's disease that might interfere with function. Conclusion  The decrease in elastic fibre concentration and changes in microscopic features may contribute to erectile dysfunction by impairing the veno‐occlusive function of the tunica albuginea.

These findings suggest that birth trauma simulated by ballooning and ovariectomy may contribute to stress urinary incontinence. The alteration in smooth muscle caveolae as well as the membrane protein caveolin may have a role in functional alterations caused by birth trauma and ovariectomy.

OBJECTIVE To present evidence that rats fed a high‐fat diet could serve as a useful animal model to study both lower urinary tract symptoms (LUTS) and erectile dysfunction (ED), as recent epidemiological studies have shown a strong association between LUTS and ED but the physiological basis behind this relationship is unknown. MATERIALS AND METHODS In all, 24 male Sprague‐Dawley rats were divided into two groups: nine controls were fed a ‘normal’ diet and 15 were fed a high‐fat diet (hyperlipidaemic rats). After 6 months all the rats had bladder and erectile functions evaluated using awake cystometry and cavernosal nerve electrostimulation, respectively. After the functional studies were completed, the penis, prostate and bladder were collected for immunohistochemical analysis. RESULTS The hyperlipidaemic rats had significantly higher serum cholesterol and low‐density lipoprotein than the controls (P < 0.05). The hyperlipidaemic rats also had significantly worse erectile function (P = 0.004) and developed more bladder overactivity (P = 0.004) than the controls. In the hyperlipidaemic rats there was significant muscle hypertrophy in the peri‐urethral lobe of the prostate (P < 0.001) and in the bladder (P < 0.05). There was also greater P2X1 (purinoceptor) staining as well as other molecular changes in the bladder of the hyperlipidaemic rats. CONCLUSIONS In this hyperlipidaemic rat model three abnormalities were consistently detected: prostatic enlargement, bladder overactivity, and ED. This rat model could be a useful research tool for understanding the common causes of LUTS and ED, as well as facilitating the development of preventive measures and better therapies to treat both conditions.

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