CORPOREAL STRUCTURAL AND VASCULAR MICRO ARCHITECTURE WITH X-RAY MICRO COMPUTERIZED TOMOGRAPHY IN NORMAL AND DIABETIC RABBITS: HISTOPATHOLOGICAL CORRELATION

Endothelial Dysfunction and Ischemia-Modified Albumin Levels in Males with Diabetic and Nondiabetic Erectile Dysfunction

In this study, we aimed to determine endothelial dysfunction and ischemia-modified albumin (IMA) levels in patients diagnosed with erectile dysfunction (ED) and to examine the relationship between these and diabetes disease. 86 male patients (46 patients with diabetes, age: $51.5\pm 9.2$ and 40 patients with nondiabetes (control group), age: $54.78\pm 12.2$ ) were included in the study. IMA, a new indicator of tissue ischemia and oxidative stress, was checked. Superoxide dismutase (SOD) activity, another oxidative stress indicator, was examined. Endothelin-1 (ET-1), one of the parameters of endothelial dysfunction, was measured. Additionally, endothelial function was evaluated with flow-mediated vasodilatation (FMD). Student’s $t$ -test was used for statistical evaluation. $p$ values less than 0.05 were considered statistically significant. SOD activity was significantly lower in the diabetic group than in the control group, and ET-1 was significantly higher ( $p<0.001$ ). IMA was found to be significantly higher in the diabetic group than the control group ( $p<0.001$ ). FMD was significantly lower in diabetic group compared to the control group ( $p<0.002$ ). According to our findings, the co-occurrence of erectile dysfunction and diabetes demonstrates a complex condition that includes endothelial dysfunction, oxidative stress, and tissue ischemia. When the correlation of indicators, which are markers, was examined, the severity of the co-occurrence of diabetes and erectile dysfunction was again demonstrated.

X-ray micro-computed tomography in the assessment of penile cavernous fibrosis in a rabbit castration model

BACKGROUND

Current assessment methods of penile cavernous fibrosis in animal models have limitations due to the inability to provide complex and volume analysis of fibrotic alterations.

OBJECTIVE

The aim was to evaluate micro-computed tomography (micro-CT) for assessment of cavernous fibrosis and compare it with histological, histochemical, immunohistochemical, and RT-PCR analysis.

MATERIALS AND METHODS

A controlled trial was performed involving 25 New Zealand male rabbits with induced testosterone deficiency by orchidectomy. Penile samples were obtained before and after 7, 14, 21, 84 days from orchidectomy. We consistently performed: a) gray value analysis of corpora cavernosa 3D models reconstructed after micro-CT; b) morphometry of smooth muscles/connective tissue ratio, collagen type I/III ratio, and area of TGF-beta-1 expression in corpora cavernosa; c) RT-PCR of TGF-beta-1 expression.

RESULTS

Micro-CT allowed visualization of penile structures at the resolution comparable to light microscopy. Gray values of corpora cavernosa decreased from 1673 (1512-1773) on the initial day to 1184 (1089-1232) on 21 day (p < 0,005); however, on 84 day, it increased to 1610 (1551-1768). At 21 and 84 days, there were observed a significant decrease in smooth muscle/connective tissue ratio and a significant increase in collagen type I/III ratio (p < 0,05). TGF-beta1 expression increased on 84 day according to immunohistochemistry (p < 0,005). RT-PCR was impossible to conduct due to the absence of RNA in obtained samples after micro-CT.

DISCUSSION AND CONCLUSIONS

Micro-CT provided 3D visualization of entire corpora cavernosa and assessment of radiodensity alterations by gray value analysis in fibrosis progression. We speculate that gray value changes at early and late fibrosis stages could be related to tissue reorganization. RT-PCR is impossible to conduct on tissue samples studied by micro-CT due to RNA destruction. We also suggest that micro-CT could negatively affect the immunohistochemical outcome, as a significant increase of TGF-beta-1 expression occurs later than histological fibrotic signs. This article is protected by copyright. All rights reserved.

miR-195-5p Regulates the Phenotype Switch of CCSM Cells by Targeting Smad7

Introduction

Phenotype switch refers to the process in which smooth muscle cells change from contractile type to synthetic type and acquire the ability of proliferation. Phenotypic transformation involves many changes of cell function, such as collagen deposition and fibrosis, which affect the normal erectile function of penis.

Aim

To investigate the role of miR-195-5p in regulating the Phenotype switch of the corpus cavernosum smooth muscle (CCSM) cells.

Methods

A small mother against decapentaplegic 7(Smad7) virus vector and a miR-195-5p mimics or an si-Smad7 viral vector and a miR-195-5p inhibitor were transfected into CCSM cells. The cells were obtained by primary culture of rat corpus cavernosum smooth muscle tissue. Real-time polymerase chain reaction (PCR) experiments, Western blotting, hematoxylin-eosin (HE) staining, transwell experiments, MTT assays, and flow cytometry were used to detect miR-195-5p, Smad7, phenotype switch markers of CCSM cells and related protein expression, as well as changes in cell morphology, migration, proliferation and apoptosis.

Main Outcome Measure

To study the regulation of miR-195-5p in CCSM cells by overexpression and silencing strategies.

Results

Overexpressed miR-195-5p promoted the transformation of CCSM cells from a contractile type to a synthetic type. Meanwhile, the migration ability and proliferation ability of CCSM cells increased, and the apoptosis rate decreased. The expression-silencing of miR-195-5p gave rise to the opposite effect. The results of the rescue experiment demonstrated that overexpressed Smad7 rescued the inhibitory of the switch of the CCSM cell phenotype from the contractile type to the synthesis type caused by overexpression of miR-195-5p alone. Moreover, the enhancement effect of the migration ability and proliferation ability of CCSM cells was also eliminated, and the apoptosis rate was increased. Silencing miR-195-5p and Smad7 at the same time resulted in the opposite effect.

Conclusion

miR-195-5p may regulate the phenotype switch of CCSM cells by targeting Smad7.

Zhang J, Zhang X, Zhang J, et al. miR-195-5p Regulates the Phenotype Switch of CCSM Cells by Targeting Smad7. Sex Med 2021;9:100349.

Erectile Dysfunction in Type-2 Diabetes Mellitus Patients: Predictors of Early Detection and Treatment

PURPOSE

To identify risk factors and potential predictors of erectile dysfunction (ED) in type-2 diabetes mellitus (T2DM) patients for early detection and treatment.

METHODS

A retrospective cohort was used to assess the clinical data of 105 diabetic patients with ED from May 2019 to April 2020 age-matched to 105 diabetic patients without ED. Potential risk factors that could contribute to ED were compared between the groups. Erectile function was evaluated using the International Index of Erectile Function-5 questionnaire.

RESULTS

There were higher rates of diabetic peripheral neuropathy (p = 0.036) and retinopathy (p < 0.001), longer duration of diabetes (p < 0.001), lower estimated glomerular filtration rate (p = 0.010) values, and higher uric acid (p < 0.001) and C-reactive protein (p = 0.001) levels in the ED group compared to the non-ED group. Multivariate logistic analysis identified uric acid, diabetic retinopathy, and T2DM course as independent predictors of diabetic ED. Diabetics with retinopathy and T2DM for ≥49 months were 3.028 and 3.860 times more likely to have ED, respectively. Uric acid values ≥392.5 μmol/L were associated with 18.638 times greater risk of having ED, though the values were within normal range.

CONCLUSION

In T2DM patients, higher uric acid (≥392.5 μmol/L), longer diabetes duration (≥49 months), and the presence of diabetic retinopathy were important and reliable predictors for diabetic ED. For patients who have high risk factors for developing ED, diligent screening and early treatment are necessary.

Complementary use of bioluminescence imaging and contrast-enhanced micro-computed tomography in an orthotopic brain tumor model

Small animal models are crucial to link molecular discoveries and implementation of clinically relevant therapeutics in oncology. Using these models requires noninvasive imaging techniques to monitor disease progression and therapy response. Micro-computed tomography (CT) is less studied for the in vivo monitoring of murine intracranial tumors and traditionally suffers from poor soft tissue contrast, whereas bioluminescence imaging (BLI) is known for its sensitivity but is not frequently employed for quantifying tumor volume. A widely used orthotopic glioblastoma multiforme (GBM) tumor model was applied in nude mice, and tumor growth was evaluated by BLI and contrast-enhanced microCT imaging. A strong correlation was observed between CT volume and BLI-integrated intensity (Pearson coefficient (r)  =  .85, p  =  .0002). Repeated contouring of contrast-enhanced microCT-delineated tumor volumes achieved an intraobserver average pairwise overlap ratio of 0.84 and an average tumor volume coefficient of variance of 0.11. MicroCT-delineated tumor size was found to correlate with tumor size obtained via histologic analysis (Pearson coefficient (r)  =  .88, p  =  .005). We conclude that BLI intensity can be used to derive tumor volume but that the use of both contrast-enhanced microCT and BLI provides complementary tumor growth information, which is particularly useful for modern small animal irradiation devices that make use of microCT and BLI for treatment planning, targeting, and monitoring.

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.

How to treat erectile dysfunction in men with diabetes: from pathophysiology to treatment

Erectile dysfunction (ED) is highly prevalent affecting at least 50 % of men with diabetes mellitus (DM). DM may cause ED through a number of pathophysiological pathways. These include neuropathy, endothelial dysfunction, cavernosal smooth muscle structural/functional changes, and hormonal changes. Lifestyle changes, diabetes control, and treatment of hypogonadism are important as the first step in ED management since there is no curative treatment for ED. Phosphodiesterase type 5 inhibitors (PDE5i) are the first-line treatment option. Intracavernous administration of vasoactive drugs is commonly used as a second-line medical treatment when PDE5i have failed. Alprostadil is the most widely used drug in this second-line setting. The combination of papaverine, phentolamine, and alprostadil represents the most efficacious intracavernous pharmacologic treatment option that may save non-responders to alprostadil. Penile prosthesis implantation can be considered in treatment refractory cases, with excellent functional and safety results in the properly informed patients.

A study of the early changes of the level of calcitonin gene-related Peptide and histopathology of penises of rats with experimentally induced type I diabetes mellitus by streptozocin

Introduction

Diabetes mellitus (DM) is a multiorgan disease that leads to neurovascular complications that disturb the normal erectile function.

Aim

The aim of the current work was to study the early changes occurring in the level of calcitonin gene-related peptide (CGRP) and histopathological changes in penile tissues of uncontrolled diabetic rats.

Materials and Methods

This study was carried on 50 adult male Sprague-Dawley rats divided into two main groups: group I (control, n = 10) and group II (diabetic, n = 40). Type I DM was induced by a single intraperitoneal injection of streptozotocin (60 mg/kg). The tissue level of CGRP and histopathological examination of rat penises were assessed at 2, 4, 6, and 8 weeks after induction of DM.

Results

CGRP was higher in the diabetic group at 4, 6, and 8 weeks than in the control group. However, endothelial changes and decreased smooth muscles mass started only 2 weeks after induction of DM.

Conclusion

Deterioration of histopathological features of the uncontrolled diabetic rats corporeal tissues is time dependent. Furthermore, vascular changes seem to precede the neurological changes. El-Kamshoushi AAM, Abdallah WI, Helal SF, El Azhary NM, and Hassan EM. A study of the early changes of the level of calcitonin gene-related peptide and histopathology of penises of rats with experimentally induced type I diabetes mellitus by streptozocin. Sex Med 2013;1:21–29.

Early onset of fibrosis within the arterial media in a rat model of type 2 diabetes mellitus with erectile dysfunction

OBJECTIVES

To determine, in the obese Zucker fa/fa rat (OZR), whether the loss in smooth muscle cells (SMCs) as well as the increase in fibrosis that occurs within the corpora cavernosa accompanying corporal veno-occlusive dysfunction (CVOD), also occurs within the media of the arterial tree.

MATERIALS AND METHODS

The penis and aorta from both 7-month-old male diabetic OZR (5 months of diabetes) and aged-matched nondiabetic lean Zucker rats (LZR) rats were harvested (eight per group). The penis and aorta were subjected to histo- or immnohistochemistry, followed by quantitative image analysis (QIA) to determine the contents of SMC, collagen and the pro-fibrotic transforming growth factor (TGF)beta1. The turnover of SMCs was assessed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling (TUNEL) and proliferating cell nuclear antigen (PCNA) assays. Quantitative Western blots determined calponin (SMC marker) and PCNA, and hydroxyproline was used for collagen. In vitro relaxation of corporal strips was measured.

RESULTS

In vitro relaxation of corporal tissue from OZR was considerably less than in the LZR. In the media of the penile dorsal artery (PDA) of OZR, there was a considerable reduction in the SMC content and the SMC/collagen ratio, as well as an increase in apoptosis, but there were no changes in PCNA or TGFbeta1 expression, or in the intima-media/lumen ratio. In the aorta of the OZR, in contrast to the PDA, there was a reduction in PCNA as well as a more pronounced decrease in the SMC/collagen ratio, mainly from an increase in collagen, but there were no changes in TGFbeta1 or the wall/lumen morphometry. In the OZR, Western blots of aortic tissue confirmed the decrease in PCNA and a reduction in the SMC marker calponin.

CONCLUSIONS

These data show that 5 months after the onset of hyperglycaemia in the OZR, the rats develop both abnormal corporal SMC relaxation and a generalized fibrosis of the arterial media of both the large and small diameter vessels. It is possible that this pan-fibrosis of the media of the arterial system might contribute to the diabetes-related ED that occurs during this period in this rat model.

Impaired nerve-mediated relaxation of penile tissue from caveolin-1 deficient mice

Caveolin-1-deficient mice are characterised by a high vascular NO production. Because NO-dependent smooth muscle relaxation is considered to play an important role in penile erection, it was hypothesized that the erectile function would be affected by genetic ablation of caveolae. This study assessed penile erectile mechanisms in caveolin-1 knockout (KO) mice ex vivo. Immunofluorescence confirmed caveolin-1 expression primarily in the endothelium surrounding the sinusoids of the corpus cavernosum, but also in smooth muscle cells of the sinusoidal bundles. In KO mice, caveolin-1 was absent, and the expression of the caveola-associated protein PTRF-Cavin was reduced. Nitric oxide synthase (endothelial and neuronal) and caveolin-3 levels were not affected, and staining of the neuronal marker PGP 9.5 did not disclose any apparent change in the density or pattern of innervation. Moreover, no apparent morphological differences were noted. Functionally, the force response following stimulation of alpha(1)-adrenergic receptors, and the sensitivity to the Rho-kinase inhibitor Y27632, were unaltered, whereas relaxation of alpha(1)-precontracted corpus cavernosum in response to electrical field stimulation and the muscarinic agonist carbachol were impaired. The nitric oxide donor sodium nitroprusside produced less relaxation in KO as compared to wild type corpus cavernosum. We conclude that nerve-mediated dilatation of the corpus cavernosum is impaired in the absence of caveolin-1, and that this is due in part to reduced sensitivity of the target tissue to NO. All in all our data support an important role of caveolin-1 in penile erection.

Treatment strategies for diabetic patients suffering from erectile dysfunction

Erectile dysfunction is a common complication of diabetes. Clinical practice has no treatment modality specifically designed for the difficult to treat diabetic erectile dysfunction due to the multifactorial and complex pathophysiology of development. PDE type 5 inhibitors are the first-line treatment option. Non-responders should have total and free testosterone checked and testosterone replacement is recommended for hypogonadal patients. For patients who cannot take PDE type 5 inhibitors, or are proven non-responders, the vacuum constriction device continues to serve as a major treatment option. Intracavernosal injection is the most effective medical therapy for diabetic erectile dysfunction despite its high dropout rate. Use of the Medicated Urethral System for Erection to overcome the disadvantages of needle injection is disappointing due to lack of effectiveness. Penile prosthesis will continue to play an important role in diabetic patients with severe erectile dysfunction in coming years.

Retrospective motion gating in small animal CT of mice and rats

OBJECTIVES

Implementation and evaluation of retrospective respiratory and cardiac gating of mice and rats using a flat-panel volume-CT prototype (fpVCT).

MATERIALS AND METHODS

Respiratory and cardiac gating was implemented by equipping a fpVCT with a small animal monitoring unit. ECG and breathing excursions were recorded and 2 binary gating signals derived. Mice and rats were scanned continuously over 80 seconds after administration of blood-pool contrast media. Projections were chosen to reconstruct volumes that fall within defined phases of the cardiac/respiratory cycle.

RESULTS

Multireader analysis indicated that in gated still images motion artifacts were strongly reduced and diaphragm, tracheobronchial tract, heart, and vessels sharply delineated. From 4D series, functional data such as respiratory tidal volume and cardiac ejection fraction were calculated and matched well with values known from literature.

DISCUSSION

Implementation of retrospective gating in fpVCT improves image quality and opens new perspectives for functional cardiac and lung imaging in small animals.

Mouse model of erectile dysfunction due to diet-induced diabetes mellitus

OBJECTIVES

To determine whether diet-induced diabetes mellitus (DM) in mice would reproduce the major features of human erectile dysfunction (ED) because DM is a significant risk factor in the development of ED.

METHODS

In total, 150 C57BL6 (bl6) mice were divided into six groups of 25 mice each. Of these 150 mice, 125 were fed a high-fat (45% of total calories) diet for the final 4 (group 2), 8 (group 3), 12 (group 4), 16 (group 5), or 22 (group 6) weeks. Group 1 was fed a normal diet. The mice were 22 to 25 weeks old at study termination. The corporal tissues were harvested and studied for endothelium-dependent and endothelium-independent vasoreactivity, endothelial and smooth muscle cell content by immunohistochemistry, nitric oxide synthase expression by nicotinamide adenine dinucleotide-diaphorase staining, and apoptosis by terminal deoxynucleotidyl transferase biotin-D-UTP nick-end labeling staining.

RESULTS

The blood glucose levels were greater in groups 2 to 6 compared with those in group 1. The vasoreactivity, endothelial cell content, and smooth muscle/collagen ratio were lower and apoptosis were greater in the DM mice (P = 0.0001, P = 0.10, P = 0.0002, P <0.001, and P <0.001, respectively). Significantly decreased nitric oxide synthase expression and significantly increased apoptosis (P <0.0001 each) was found in the high-fat diet mice.

CONCLUSIONS

Corporal tissue from mice with diet-induced DM demonstrated many of the major functional, structural, and biochemical changes found in humans with ED. This model should serve as a valuable tool for advancing our understanding of the role DM plays in the pathogenesis of ED.

Testosterone Regulates RhoA/Rho-Kinase Signaling in Two Distinct Animal Models of Chemical Diabetes

INTRODUCTION

The contractile RhoA/Rho-kinase (ROCK) signaling pathway is upregulated in penile tissue in animal models of experimental diabetes and has been proposed to contribute to diabetes-related erectile dysfunction (ED).

AIM

To investigate the effect of testosterone (T) on the RhoA/ROCK signaling in diabetes.

METHODS

We used two distinct animal models of chemical diabetes (alloxan-induced in the rabbit and streptozotocin-induced in the rat) with or not T supplementation.

MAIN OUTCOME MEASURES

The effect of diabetes and T supplementation on RhoA/ROCK signaling was evaluated as responsiveness to the selective ROCK inhibitor Y-27632 either by "in vitro" contractility study (diabetic rabbit) or "in vivo" as erectile response elicited by intracavernous injections (diabetic rats). RhoA/ROCK gene and protein expression were also analyzed.

RESULTS

In both models, hypogonadism was observed, characterized by reduced T plasma level and androgen-dependent accessory glands atrophy. Diabetic animals showed a significant increase in responsiveness to increasing concentrations of Y-27632. T substitution (30 mg/kg, weekly) completely prevented hypogonadism and diabetes-induced penile hypersensitivity to Y-27632. To test whether this effect was due to a T-dependent regulation of RhoA/ROCK gene expression, we measured RhoA/ROCK mRNA. Both isoforms of ROCK (ROCK1/ROCK2) were analyzed by real-time reverse transcriptase polymerase chain reaction (RT-PCR) in rat penile samples. We found that ROCK1 mRNA was significantly increased (P < 0.05) in penile tissues from diabetic animals and maintained at the control values by T, as also confirmed by semiquantitative RT-PCR in rabbit. Conversely, RhoA and ROCK2 mRNA expression was not influenced either by diabetic condition or by T administration. Accordingly, ROCK1 protein expression, as evaluated by Western blot and immunohistochemistry analysis, was increased in penile samples from diabetic animals and normalized by T.

CONCLUSIONS

Our data further support the hypothesis that the overexpression of RhoA/ROCK signaling contributes to diabetes-related ED. Moreover, treating hypogonadism in course of diabetes may maintain erectile function also by normalizing RhoA/ROCK pathway upregulation.

Contrast-Enhanced MRI and Micro-CT Adopted for Evaluation of a Lipid-Lowering and Anticoagulant Herbal Epimedium-Derived Phytoestrogenic Extract for Prevention of Steroid-Associated Osteonecrosis

We developed an alternative steroid-associated osteonecrosis (ON) rabbit model using a combination of a single injection of low-dose lipopolysaccharide (LPS) and three subsequent injections of pulsed high-dose methylprednisolone (MPS).The usefulness of this experimental ON model was evaluated using both conventional and advanced bio-imaging techniques, including contrast-enhanced dynamic MRI and a high-resolution micro-CT. Details on establishment of methodology are described, which were adopted into an efficacy study on a herbal Epimedium-derived phytoestrogenic extract (HEPE) developed for prevention of steroid-associated ON using an established rabbit model. The underlying mechanisms of HEPE for prevention of steroid-associated ON were found to be associated with inhibition of both intravascular thrombosis and extravascular bone marrow lipid deposition, the two known mechanistic pathways in pathogenesis of ON. Our experimental results provide for potential clinical trials or applications of HEPE in the prevention of ON among hig-hrisk patients undergoing steroid treatment.

Diabetic erectile dysfunction--an indicator of generalised endothelial function per se?

Erectile dysfunction (ED) affects up to 70% of men with diabetes. However, the pathophysiology of ED in diabetes remains uncertain with both neuronal and vascular factors cited. We examined whether ED is an indicator of generalized endothelial dysfunction. A unique group of diabetic patients free from established conventional cardiac risk factors were investigated. Forearm bloodflow responses to nitroprusside and acetylcholine on 11 diabetic men with ED and 11 potent diabetic men were measured by venous plethysmography. Patient characteristics between the impotent and potent patients were similar except for Hba1c which was higher in the group with ED (8.35% vs. 7.03%: p = 0.003). Both groups showed increases in FBF to incremental infusions of nitroprusside and acetylcholine but the area under curve (AUC) were similar in the ED and the non-ED groups (p = 0.16 and p = 0.17, respectively). We demonstrated that ED in patients with type 2 diabetes is not associated with additional generalized endothelial dysfunction.

Testosterone Undecanoate Restores Erectile Function in a Subset of Patients with Venous Leakage: A Series of Case Reports

INTRODUCTION

Androgens are critical for maintaining penile structure and function and androgen deficiency alters the function of the corporal veno-occlusive mechanism in animal models. However, there are limited research and data supporting this association in humans.

METHODS

Case reports of hypogonadal men (N = 12) with low plasma testosterone and moderate to severe erectile dysfunction are presented. Comorbidities varied, including diabetes mellitus type I or II, metabolic syndrome with possible related hypertension, dyslipidemia, or obesity. Oral phosphodiesterase type 5 (PDE5) inhibitor therapy did not improve erectile function. Each patient underwent baseline dynamic infusion pharmacocavernosometry and cavernosography revealing various degrees of corporal veno-occlusive dysfunction. The patients underwent treatment with 1,000 mg injectable testosterone undecanoate (Nebido) on day 1, followed by another injection after 6 weeks and every 3 months thereafter. Dynamic infusion pharmacocavernosography was repeated in all 12 patients after 3 months of treatment.

RESULTS

Five of the 12 patients reported significant improvement in erectile function within 12-20 weeks of androgen treatment and are currently under follow-up. Compared with baseline pharmacocavernosography, repeat radiological studies in patients who reported improvement in erectile function did not show veins draining the corporal bodies. The patients who responded to androgens also noted improvement in sexual desire domain (International Index of Erectile Function [IIEF] scores increased from 4 +/- 0.7 to 8 +/- 0.3) and erectile function domain (IIEF scores increased from 6 +/- 2 to 24 +/- 1).

CONCLUSION

The observations made in these limited series of case reports suggest that testosterone improved erectile function in hypogonadal patients by restoring veno-occlusive function. Prospective, multi-institutional, double-blind placebo-controlled trials in hypogonadal patients are indicated.

REVIEWS: Are Androgens Critical for Penile Erections in Humans? Examining the Clinical and Preclinical Evidence

Androgens are deemed critical for penile-tissue development, growth, and maintenance of erectile function, however, their role in erection, especially in humans, remains controversial. In this review, we summarize information from clinical and animal model studies to provide a comprehensive and rational argument for the role of androgens, or lack thereof, on penile erection ability in humans. The goal of this review is to present the clinical and preclinical evidence available in the literature with regard to testosterone and erectile physiology and engage the reader in this discussion. Ultimately, each reader will have to form his or her own conclusions based on the existing evidence. In humans, androgen-deficiency manifestations are noted in clinical situations such as: (i) inadequate development of the penis; and (ii) loss of erectile function in prostate cancer and benign prostatic hyperplasia patients managed with medical or surgical castration or antiandrogen therapy. Androgen treatment causes: (i) improvement in sexual function in hypogonadal patients treated with androgen supplementation; (ii) improvement in nocturnal penile tumescence in hypogonadal patients treated with androgens; (iii) improvement in erectile function with androgen supplementation in patients who did not respond to phosphodiesterase type 5 inhibitor therapy initially; and (iv) improvement in the well-being, mood, energy, and sexual function in aging men who have testosterone deficiency treated with androgen therapy. In contrast to animals, especially rodents in which the adrenal cortex does not synthesize androgens, the human adrenal is a source of peripherally circulating androgen precursors, thus, complete androgen insufficiency may not be observed in men at a younger age. Furthermore, in light of the concept that a threshold of androgen levels exists in animals and humans below which sexual function is diminished, further contributes to the complexity of understanding androgens role in erections, especially in humans. Nevertheless, based on the preclinical and clinical data available in the literature, to date, we infer that androgens play a critical role in maintaining erectile physiology in humans.

Impairment of endothelium- and nerve-mediated relaxation responses in the cavernosal smooth muscle of experimentally diabetic rabbits: role of weight loss and duration of diabetes

The effects of short- and long-term experimental diabetes on corporal nerve, endothelium and smooth-muscle responses were investigated, and the reasons for possible alterations in corporal smooth muscle responses such as hyperglycaemia, duration of experimental diabetes and/or altered tissue weight were evaluated. Rabbits were injected with alloxan (125 mg/kg) to induce diabetes. Age-matched non-diabetic and diabetic (3 and 9 weeks) and weight-matched non-diabetic groups (9 weeks) were used as control. In all groups, relaxation (carbachol, electrical field stimulation and sodiumnitroprusside) responses were examined. The relaxation responses were expressed as percentage of the precontraction to phenylephrine and as g response/g tissue weight. The effects of elevated glucose were also examined by incubating cavernosal strips in Krebs-Henseleit solution containing 44.4 mM glucose for 6 h. Cavernosal tissues of non-diabetic and 9-week diabetic rabbits were evaluated histologically. Sodiumnitroprusside (10(-7)-10(-4) M) responses were similar in all groups. Relaxation responses to electrical field stimulation (10 s train; amplitude 50 V; frequency 0.5-32 Hz; width 0.8 ms) were only attenuated in the 9-week diabetic group compared to the non-diabetic group. Carbachol (10(-8)-3 x 10(-5) M) responses were attenuated in both diabetic groups. When the relaxation responses expressed as g response/g tissue weight were evaluated, results were similar compared to those expressed as percentage of phenylephrine (10(-5) M). Neither carbachol nor electrical field stimulation mediated responses were impaired with glucose incubation. No morphological degenerations were observed in the endothelium. Diabetes may interfere with the synthesis and/or release of nitric oxide from both nerves and endothelium in corpus cavernosum, and alterations in endothelium-derived responses occur earlier than neurological disturbances. The sensitivity of cavernosal smooth muscle to nitric oxide did not alter in diabetes. Attenuation of responses was not due to decreased tissue weight caused by diabetes.

Micro-CT of the Human Lung: Imaging of Alveoli and Virtual Endoscopy of an Alveolar Duct in a Normal Lung and in a Lung with Centrilobular Emphysema—Initial Observations

The appearance of human lung parenchyma at the structural level of alveoli was investigated by the use of micro-computed tomography (CT). Approval for use of autopsy lungs was given by the head of the pathology institute of the university, in accordance with the requirements of the State Ministry of Science and Arts and without the need for institutional review board approval. Two human lungs (one normal lung and one lung with centrilobular emphysema of a mild to moderate degree) were inflated and fixed with hot formalin vapor. Lung specimens excised from the superior segment of the left lower lobe (B6) were stained with silver nitrate in a vacuum and investigated at a volume of interest of 4 mm for each side with a voxel size of 14 mum. Normal-size and enlarged alveoli became visible. A three-dimensional reconstruction of the terminal airspaces made virtual endoscopy of the alveolar ducts possible.

Analysis of 3D bone ingrowth into polymer scaffolds via micro-computed tomography imaging

This paper illustrates the utility of micro-computed tomography (micro-CT) to study the process of tissue engineered bone growth. A micro-CT facility for imaging and visualising biomaterials in three dimensions (3D) is described. The facility is capable of acquiring 3D images made up of 2000(3) voxels on specimens up to 60mm in extent with resolutions down to 2 microm. This allows the 3D structure of tissue engineered materials to be imaged across three orders of magnitude of detail. The capabilities of micro-CT are demonstrated by imaging the Haversian network within human femoral cortical bone (distal diaphysis) and bone ingrowth into a porous scaffold at varying resolutions. Phase identification combined with 3D visualisation enables one to observe the complex topology of the canalicular system of the cortical bone. Imaging of the tissue engineered bone at a scale of 1cm and resolutions of 10 microm allows visualisation of the complex ingrowth of bone into the polymer scaffold. Further imaging at 2 microm resolution allows observation of bone ultra-structure. These observations illustrate the benefits of tomography over traditional techniques for the characterisation of bone morphology and interconnectivity and performs a complimentary role to current histomorphometric techniques.

Quantitative microcomputed tomography analysis of collateral vessel development after ischemic injury

Transgenic mouse models are increasingly being used to investigate the functions of specific growth factors or matrix proteins to design therapeutic strategies for controlling blood vessel growth. However, the available methodologies for evaluating angiogenesis and arteriogenesis in these models are limited by animal size, user subjectivity, the power to visualize the three-dimensional vessel networks, or the capability to employ a vigorous quantitative analysis. In this study, we employed contrast-enhanced microcomputed tomography imaging to assess collateral development after induction of hindlimb ischemia in the mouse. The morphological parameters vessel volume, connectivity, number, thickness, thickness distribution, separation, and degree of anisotropy were evaluated in control and surgery limbs 0, 3, and 14 days postsurgery. Results indicate that the vascular volume of the surgically manipulated limb was reconstituted as early as 3 days after femoral artery excision through development of a series of highly connected, small caliber, closely spaced, and isotropically oriented collateral vessels. Parametric analyses were completed to assess the sensitivity of the calculated morphological parameters to variations in image binarization threshold and voxel size. Images taken at the 36-μm voxel size were found to be optimal for evaluating collateral vessel formation, whereas 8- to 16-μm voxel sizes were needed to resolve smaller vascular structures. This study demonstrates the utility of microcomputed tomography as a robust method for quantitative, three-dimensional analysis of blood vessel networks. Whereas these initial efforts focused on the mouse hindlimb ischemia model, the developed techniques may be applied to a variety of model systems to investigate mechanisms of angiogenesis and arteriogenesis.

Sonic hedgehog cascade is required for penile postnatal morphogenesis, differentiation, and adult homeostasis

The penis is unique in that it undergoes morphogenesis and differentiation primarily in the postnatal period. For complex structures such as the penis to be made from undifferentiated precursor cells, proliferation, differentiation, and patterning are required. This process involves coordinated activity of multiple signals. Sonic hedgehog (Shh) forms part of a regulatory cascade that is essential for growth and morphogenesis of many tissues. It is hypothesized that the penis utilizes regulatory mechanisms similar to those of the limb and accessory sex organs to pattern penile postnatal morphogenesis and differentiation and that the Shh cascade is critical to this process. To test this hypothesis, Shh, BMP-4, Ptc, and Hoxa-10 localization and function were examined in Sprague-Dawley rat penes by means of quantitative reverse transcription polymerase chain reaction, in situ hybridization, immunohistochemistry, and Western blotting. These genes were expressed in the penis during postnatal morphogenesis in a spatially and temporally restricted manner in adjacent layers of the corpora cavernosal sinusoids. The function of Shh and BMP-4 is to establish and maintain corpora cavernosal sinusoids. The data suggest that Ptc and Hoxa-10 are also important in penile morphogenesis. The continuing function of Shh and targets of its signaling in maintaining penile homeostasis in the adult is significant because disruption of Shh signaling affects erectile function. This is the first report that demonstrates the significant role that Shh plays in establishing and maintaining penile homeostasis and how this relates to erectile function. These studies provide valuable insight that may be applied to improve treatment options for erectile dysfunction.

A Rho-kinase inhibitor, soluble guanylate cyclase activator and nitric oxide-releasing PDE5 inhibitor: novel approaches to erectile dysfunction

Approximately 50% of men aged over 40 suffer from male erectile dysfunction. Treatment options have widened since the launch of the phosphodiesterase type 5 (PDE5) inhibitor, sildenafil citrate (Viagra trade mark ). However, a certain portion of the patient population, such as diabetics, do not gain significant benefit from PDE5 inhibitors, possibly due to a lack of endogenous nitric oxide. Therefore, new treatment modalities based on the absence of endogenous nitric oxide have been developed. Among them are Rho-kinase inhibitors, soluble guanylate cyclase activators and nitric oxide-releasing PDE5 inhibitors. The available data concerning these compounds will be summarised and their therapeutic potential for male erectile dysfunction will be discussed.