Ultra-structural changes in collagen of penile tunica albuginea in aged and diabetic rats

Penile Dimensions of Diabetic and Nondiabetic Men With Erectile Dysfunction: A Case-Control Study

This study aimed to report penile dimensions in diabetic and nondiabetic men with erectile dysfunction (ED) and correlate their dimensions with other study variables. A case-control study was designed through retrospective data analysis of diabetic and nondiabetic patients consulting for ED and a control group ( n = 105, each group). Study data retrieved included history, clinical evaluation, and penile dimensions (pendulous length [PL], total length [TL], and circumference [CF]) at flaccid and erect states. Results identified that patients had lower values (mean, cm) for almost all penile dimensions. The diabetic patients identified significant differences in most dimensions, whether in flaccid (PL: 7.46 vs. 7.51 and 7.81, p = .11; TL: 11.8 vs. 12.77 and 12.88, p = .000; CF: 8.84 vs. 9.1 and 9.14, p = .016) or erect state (PL: 9.66 vs. 9.61 and 10, p = .092; TL: 13.96 vs. 14.88 and 15.04, p = .000; CF: 11.56 vs. 12.06 and 11.92, p = .018) as compared with the nondiabetic patients and controls, respectively. No significant correlation was detected between the dimensions and age, durations of diabetes and ED, or erectile function scores. In conclusion, diabetic and nondiabetic patients with ED presented, in varying degrees, significant decline in their penile dimensions, and this was more prevalent in diabetic patients. As changes in penile size could be a silent corollary of comorbidities, monitoring the changes in penile dimensions should be an important component of the clinical checkup of any patient with ED, especially a diabetic patient.

Is there a link between soft drinks and erectile dysfunction?

This review focuses on the potential role of soft drinks, particularly the sugar component, in the pathogenesis of erectile dysfunction (ED). We analyzed the hypothetical link between metabolic disorders, induced by sweetened soft drinks overconsumption, and ED. High caloric intake, high refined-carbohydrates, and high fructose corn syrup (HFCS) content and less satiety are main factors responsible for metabolic disorders contributing to ED development. Regular diet mistakes among human males, such as soft drink consumption, may lead to slow and asymptomatic progression of ED, finally resulting in full claimed manifestation of ED.

Effect of periodontitis on erectile function and its possible mechanism

INTRODUCTION

Periodontitis is one of the important risk factors resulting in cardiovascular diseases. Erectile dysfunction (ED) is strongly correlated with cardiovascular diseases. The expression of endothelial nitric oxide synthase (eNOS) in penile tissue has an important role in the mechanism of erection.

AIM

To investigate the effect of periodontitis on erectile function and the possible mechanism.

METHODS

After induction of periodontitis in rat, the ratio of maximum intracavernosal pressure/mean arterial pressure (ICPmax /MAP)×100, the expression of eNOS in penile tissue, the level of serum C-reactive protein (CRP) and tumor necrosis factor-α (TNF-α), and the ultrastructural changes of the cavernous tissue were examined and compared between periodontitis rats (group A) and control rats (group B).

MAIN OUTCOME MEASURE

Periodontitis significantly decrease not only the ICPmax/MAP×100 and the expression of eNOS but also the activity of NOS and the level of cyclic guanosine monophosphate (cGMP) in cavernous tissue of rat.

RESULTS

After electrostimulation by 3 and 5 voltage, the ratio of ICPmax /MAP×100 in group A was significantly less than that in group B (19.54±6.16 vs. 30.45±3.12; 30.91±5.61 vs. 50.52±9.52, respectively; P<0.05).The level of serum CRP and TNF-α in group A is significantly higher in group B (P<0.05).The quantitative real-time reverse transcription polymerase chain reaction study demonstrated no statistically significant difference in the expression of mRNA of eNOS in cavernous tissue between the two groups (P>0.05). But there was significant decrease in eNOS protein of the cavernous tissue in group A than in group B (P<0.05). Total NOS activity and cGMP level in cavernosal tissue were significantly lower in group A than in group B (P<0.05). There was no significant alternation occurred in the ultrastructures of penile cavernous tissue.

CONCLUSIONS

The function of penile erection is impaired by periodontitis. The decreased in the expression of eNOS and NOS activity in penile cavernous tissue caused by mild systemic inflammatory status in periodontitis may be one of the important risk factors of ED.

Corpus cavernosum electromyography: could it be a parameter to predict ageing?

In this study, we investigated whether electromyography of corpus cavernosum (CC-EMG) results vary with age and whether CC-EMG could be a parameter to predict ageing of cavernous smooth muscle. Recordings of electrical activity of corpus cavernosum (EACC) were retrospectively investigated in 134 patients with erectile dysfunction. Penile colour Doppler ultrasonography and cavernosometry were also performed for all of the patients. The total number and duration of EACC and amplitudes between positive and negative peaks were compared between the flask state for 10 min and after intracavernosal papaverine injection. The mean age of the 47 patients in group 1 was 35.2 ± 6.3 years (range, 23-44), the mean age of the 45 patients in group 2 was 51.1 ± 3.1 years (range, 45-56) and the mean age of the 42 patients in group 3 was 61.8 ± 4.6 years (range, 57-77). Total IIEF-5 score was 7.6 ± 2.1 in group 1, 7.9 ± 2.4 in group 2 and 7.9 ± 2.1 in group 3. There were no statistically significant differences among the groups regarding electrical potential frequencies, durations and amplitudes of electromyographic recordings.

CONCLUSION

We do not think that CC-EMG findings could be used efficiently as a predictor of ageing.

Molecular targets for diabetes mellitus-associated erectile dysfunction

Protein expression profiles in rat corporal smooth muscle tissue were compared between animal models of streptozotocin-induced diabetes mellitus (STZ-DM) and age-matched controls (AMCs) at 1 week and 2 months after induction of hyperglycemia with STZ treatment. At each time point, protein samples from four STZ-DM and four AMC rat corpora tissues were prepared independently and analyzed together across multiple quantitative two-dimensional gels using a pooled internal standard sample to quantify expression changes with statistical confidence. A total of 170 spots were differential expressed among the four experimental groups. A subsequent mass spectrometry analysis of the 170 spots identified a total of 57 unique proteins. Network analysis of these proteins using MetaCore suggested altered activity of transcriptional factors that are of too low abundance to be detected by the two-dimensional gel method. The proteins that were down-regulated with diabetes include isoforms of collagen that are precursors to fibril-forming collagen type 1; Hsp47, which assists and mediates the proper folding of procollagen; and several proteins whose abundance is controlled by sex hormones (e.g. CRP1 and A2U). On the other hand, proteins seen or predicted to be up-regulated include proteins involved in cell apoptosis (e.g. p53, 14-3-3-gamma, Serpinf1, Cct4, Cct5, and Sepina3n), proteins that neutralize the biological activity of nerve growth factor (e.g. anti-NGF 30), and proteins involved in lipid metabolism (e.g. apoA-I and apoA-IV). Subsequent Western blot validation analysis of p53, 14-3-3-gamma, and Hsp47 confirmed increased p53 and 14-3-3-gamma and decreased Hsp47 levels in separate samples. According to the results from the Western blot analysis, Hsp47 protein showed a approximately 3-fold decrease at 1 week and was virtually undetectable at 2 months in diabetic versus control. Taken together, our results identify novel candidate proteins playing a role in erectile dysfunction in diabetes resulting from STZ treatment.

Valsartan treatment reverses erectile dysfunction in diabetic rats

In order to investigate the effect of angiotensin receptor blockage (ARB) for the treatment on diabetic erectile dysfunction (ED), we used male Sprague-Dawley rats injected with 65 mg/kg streptozotocin to induce diabetes mellitus. The diabetic rats with ED were selected by hypodermic injection of apomorphine (APO) after 8 weeks of model setting. All rats were divided into four groups: G1 (normal control rats), G2 (diabetic rats treated with normal saline), G3 (diabetic rats treated with valsartan) and G4 (diabetic rats treated with spironolactone). After treatment with drugs for 8 weeks, the rate of erection for each group was evaluated after the injection of APO. The intracavernous pressure (ICP) of each rat was then recorded before and after the electrostimulation of the major pelvic ganglion. The rates of erection and the ICP after electrostimulation for diabetic rats treated with valsartan were significantly higher than that in diabetic rats treated with normal saline and spironolactone. The ARB may be an effective therapy for diabetics with ED.

Microarray analysis reveals novel gene expression changes associated with erectile dysfunction in diabetic rats

To investigate the full range of molecular changes associated with erectile dysfunction (ED) in Type 1 diabetes, we examined alterations in penile gene expression in streptozotocin-induced diabetic rats and littermate controls. With the use of Affymetrix GeneChip arrays and statistical filtering, 529 genes/transcripts were considered to be differentially expressed in the diabetic rat cavernosum compared with control. Gene Ontology (GO) classification indicated that there was a decrease in numerous extracellular matrix genes (e.g., collagen and elastin related) and an increase in oxidative stress-associated genes in the diabetic rat cavernosum. In addition, PubMatrix literature mining identified differentially expressed genes previously shown to mediate vascular dysfunction [e.g., ceruloplasmin (Cp), lipoprotein lipase, and Cd36] as well as genes involved in the modulation of the smooth muscle phenotype (e.g., Kruppel-like factor 5 and chemokine C-X3-C motif ligand 1). Real-time PCR was used to confirm changes in expression for 23 relevant genes. Further validation of Cp expression in the diabetic rat cavernosum demonstrated increased mRNA levels of the secreted and anchored splice variants of Cp. CP protein levels showed a 1.9-fold increase in tissues from diabetic rats versus controls. Immunohistochemistry demonstrated localization of CP protein in cavernosal sinusoids of control and diabetic animals, including endothelial and smooth muscle layers. Overall, this study broadens the scope of candidate genes and pathways that may be relevant to the pathophysiology of diabetes-induced ED as well as highlights the potential complexity of this disorder.

Is there any relation between serum levels of total testosterone and the severity of erectile dysfunction?

The objective of this study was to correlate the severity of erectile dysfunction (ED) with the total testosterone serum levels (TT) in a normal population. During a screening program for the early diagnosis of prostate cancer, 1071 men aged from 40 to 90 y, were invited to answer the questionnaire of the Simplified International Index of Erectile Function (IIEF-5) as a method to diagnose and classify ED. The IIEF-5 scores ranged from 1 to 25 and the ED was classified into five groups according to the scores: severe (1-7), moderate (8-11), mild-moderate (12-16), mild (17-21) and no ED (22-25). Besides the questionnaire, all subjects had their TT serum levels determined based on the blood sample obtained between 08:00 and 10:00. The analysis of the relationship between the different degrees of ED and TT levels was then studied. Of the 1071 men, 965 were included in the study (90.1%). Eighty-eight percent of these were Caucasian and 12% black. The mean age of the population was 60.7 y. The prevalence of all degrees of ED was 53.9%. The degree of ED was mild in 21.5%, mild to moderate in 14.3%, moderate in 6.3% and severe in 11.9%. The variation of TT serum concentrations was similar (P>0.05) in the different age groups. Furthermore, the TT serum levels were not different for individuals with and without ED (P>0.05) and similar concentrations of TT was observed in the different severity degrees of ED (P>0.05). Only one (0.7%) man in the group of individual with maximal score had subnormal levels of TT. ED presented a clear association with the subjects' aging, but neither correlation between TT levels and ED, nor with its severity, could be demonstrated in the present study.

Age-associated changes in collagen content and its subtypes within rat corpora cavernosa with computerized histomorphometric analysis

OBJECTIVES

To study the age-associated changes in the percentage of collagen and subtypes I, III, and IV within the corpora cavernosa in a rat model.

METHODS

The corpora cavernosa tissues were obtained from 30 male Wistar rats at three different ages. Processed with Masson's trichrome staining for collagen and with immunohistochemical staining for the collagen subtypes, the values of the collagen percentage, the percentage of area, and relative proportion of each collagen subtype within the rat corpora cavernosa were measured using an automatic image analysis system. The relationships between an increase in age and these parameters were analyzed.

RESULTS

The percentage of collagen within the corpora cavernosa was higher in the old rats (80 weeks) than in the young (20 weeks) and intermediate-age (40 weeks) rats (P = 0.02 and P = 0.25, respectively) and significantly increased with age (P = 0.021). The values of the percentage of area of collagen subtypes III and IV also increased significantly with age (P = 0.039 and P = 0.019, respectively). The value of the percentage of area of collagen subtype I was not significantly increased (P = 0.159). Also, no significant differences were found in the relative proportions of all three collagen subtypes with age among the three age groups.

CONCLUSIONS

The percentages of collagen within rat corpora cavernosa significantly increased, but not strongly, with age, especially collagen subtypes III and IV. However, the relative proportion of each subtype did not change with age. Therefore, we conclude that the amount of collagen may only partly contribute to erectile dysfunction in the aging process of the rat.

Erectile dysfunction in the ageing man

Most studies have shown an increase in the prevalence of erectile dysfunction with ageing. Penile erection is a vascular phenomenon resulting from smooth muscle relaxation, arterial dilatation and venous restriction. The atherosclerosis of the penis that occurs with ageing causes a decrease in penile oxygen tension. This change in oxygen tension impacts directly upon both the physiologic function and the trabecular structure of the corpora cavernosa. Chronic ischaemia of the penis is associated with fibrosis of smooth muscle fibres and with endothelial and neuronal NO/cGMP pathways. The effects of androgens on libido and sexual behaviour are well established but their role in the erectile mechanism remains unclear. The histologic and haemodynamic causes responsible for the erectile decline in the ageing man are reviewed.