Pedro Vendeira

Increased Endothelial Apoptotic Cell Density in Human Diabetic Erectile Tissue—Comparison with Clinical Data

INTRODUCTION Erectile dysfunction (ED) is a common complication of diabetes. Endothelial cell (EC) dysfunction is one of the main mechanisms of diabetic ED. However, loss of EC integrity has never been assessed in human diabetic corpus cavernosum. AIM To identify and quantify apoptotic cells in human diabetic and normal erectile tissue and to compare these results with each patients clinical data and erection status. METHODS Eighteen cavernosal samples were collected, 13 from diabetics with ED and 5 from nondiabetic individuals. Cavernosal structure and cell proliferation status were evaluated by immunohistochemistry. Tissue integrity was assessed by terminal transferase dUTP nick end labeling assay, an index of apoptotic cell density (ACD) established and compared with each patient age, type of diabetes, arterial risk factors number, arterial/veno-occlusive disease, response to intracavernous vasoactive injections (ICI), and penile nitric oxide release test (PNORT). MAIN OUTCOME MEASURES Establish an index of ACD and correlate those results with patient clinical data. RESULTS Nondiabetic samples presented few scattered cells in apoptosis and an ACD of 7.15 +/- 0.44 (mean apoptotic cells/tissue area mm(2) +/- standard error). The diabetic group showed an increased ACD of 23.82 +/- 1.53, and apoptotic cells were located specifically at vascular sites. Rehabilitation of these endothelial lesions seemed impaired, as no evidence of EC proliferation was observed. Furthermore, higher ACD in diabetic individuals correlated to poor response to PNORT and to ICI. CONCLUSIONS We provided evidence for the first time that loss of cavernosal EC integrity is a crucial event involved in diabetic ED. Furthermore, we were able to establish a threshold between ACD values and cavernosal tissue functionality, as assessed by PNORT and vasoactive ICI.

Characterization of VEGF and Angiopoietins Expression in Human Corpus Cavernosum during Aging

INTRODUCTION AND OBJECTIVES Erectile dysfunction (ED) is a highly prevalent and age-related disease, caused by endothelial dysfunction and impaired cavernous angiogenesis. However, cellular and molecular changes involved in erectile pathophysiology in aging male remain to be elucidated. AIM To characterize the vascular organization, concomitantly with analysis of the expression of vascular endothelial growth factor (VEGF), Angiopoietin 1 (Ang1) and Angiopoietin 2 (Ang2) in young and aged human corpus cavernosum. METHODS Human penile fragments were removed from patients submitted to penile deviation surgery (11 cases; 58-70 years) and from potential organ donors (four cases; 18-28 years) without ED or risk factors for ED. Smooth muscle and connective tissue were assessed by Massons trichrome staining and computer-assisted histomorphometry. Dual immunostaining for specific markers of endothelium (von Willebrand factor) and smooth muscle cell (alpha-actin), VEGF, Ang1 and Ang2 was assayed by fluorescence microscopy. Semi-quantification of expression of angiogenic factors was performed by Western blotting. MAIN OUTCOME MEASURES Expression of VEGF and Angiopoietins in human corpus cavernosum, using a combination of histologic stainings, and molecular biology tools in order to achieve a better understanding of cavernosal tissue remodeling with aging. RESULTS Aged human corpus cavernosum presented wider sinusoidal spaces, loss of muscle cell bundles, and increased connective tissue content. Ang1 was scarcely expressed in small clusters in smooth muscle cell cytoplasm with identical localization in both studied groups. VEGF expression was abundant in smooth muscle cell and its expression markedly decreased in aged tissue, contrasting with the expression of angiopoietins that increased in the aged corpus cavernosum. CONCLUSIONS Immunoflourescent studies of cellular markers and growth factors help clarifying vascular organization and angiogenesis mechanisms in erectile tissue. Our findings demonstrate that the organization pattern of vascular endothelium and smooth muscle components of cavernosal tissue modifies during aging. Ang1 and Ang2 upregulation in human-aged penile tissue suggest a VEGF-independent vascular remodeling mechanism.

Does Erectile Tissue Angioarchitecture Modify with Aging? An Immunohistological and Morphometric Approach

Introduction. Erectile dysfunction is a common problem in aged men; however, which vascular cavernosal alterations occur with age progression remain unclarified. Aim. Using cavernosal tissue from rats of various ages, we aimed to thoroughly assess erectile vascular-associated morphologic, immunohistological, and morphometric alterations during aging. Methods. Male Wistar rats were divided according to age in groups of 2, 6, 12, 18, 24 months old (N = 5). Cavernosal tissue of all groups was collected and processed for morphologic evaluation, immunodetection of alpha-smooth muscle actin and von Willebrand factor and morphometric quantification of vascular and smooth muscle cell (SMC) areas. Main Outcome Measures. The morphometric assessment of age-related alterations in cavernosal vascular and SMCs using the ImageJ image-processing program. Results. Morphologic and immunohistological evaluation showed a similar structure of erectile tissue among all age groups, divided in two cavernosal bodies containing numerous sinusoidal vascular spaces surrounded by SMCs. Additionally, we observed a reduction of SMC content and an increase in the caliber of vascular spaces, with aging. This was confirmed by the morphometric quantification of the vascular and SMC areas (mean area x10(3) microm(2) +/- x10(3) standard error). Two-month-old animals had a mean vascular area of 4.21 +/- 0.51, approximately 3.5-fold less than the 6-month-old group. The differences increased when comparing the youngest groups with the 12-, 18-, and 24-month-old animals, with mean measurements of 18.99 +/- 1.91, 25.23 +/- 2.76, and 26.34 +/- 2.97. Conversely, SMC areas progressively decreased between 2- and 6-month-old animals, from 6.75 +/- 0.90 to 6.38 +/- 1.24. The elderly 12-, 18-, and 24-month-old groups presented an approximated 1.5-fold reduction on SMCs area, showed by the respective measurements of 4.11 +/- 0.50, 4.01 +/- 0.35, and 4.02 +/- 0.44. Conclusions. We demonstrated that cavernosal angioarchitecture was modified with aging. The decrease in SMCs and the considerable enlargement of vascular lumens may limit the basic function of penile vascular tree in the elderly.

Aging and Orchidectomy Modulate Expression of VEGF Receptors (Flt‐1 and Flk‐1) on Corpus Cavernosum of the Rat

Abstract:  Aging and hypogonadic states are known risk factors for erectile dysfunction (ED), contributing together to vascular damage of penile tissue. In the present study, VEGF‐specific membrane receptor (VEGFR‐1/Flt‐1 and VEGFR‐2/Flk‐1) expression was studied by confocal immunofluorescence in the corpus cavernosum of control rats, rats aged 12 and 18 months, and orchidectomized Wistar rats (90 days of bilateral orchidectomy). Immunocytochemical results demonstrated VEGFR‐2 expression restricted to the endothelium in both control and orchidectomized rats. Aged animals (12 and 18 months) presented enlarged vessels with intense VEGFR‐2 endothelial staining. On the other hand, VEGFR‐1 was demonstrated in smooth muscle fibers, particularly in those that surround vessel endothelium, the endothelial expression being very low in control and orchidectomized rats. However, in the aged rats, a shift resulting in a VEGFR‐1 and VEGFR‐2 co‐localization in the endothelial cell was observed. The findings suggest an upregulation of VEGFR‐1 in the corpora cavernosa during aging in the rat, which is evident from an increased expression by endothelial cells.

Are All Metabolic Syndrome Components Responsible for Penile Hemodynamics Impairment in Patients with Erectile Dysfunction? The Role of Body Fat Mass Assessment

INTRODUCTION Erectile dysfunction (ED) is a common disease that is mostly vasculogenic in nature. ED correlates with cardiovascular risk factors, with endothelial dysfunction being the common link. Hypertension (HTA) and insulin resistance are the most important determinants of arteriogenic ED, and are also components of the metabolic syndrome (MetS), which supports a strong association between MetS and ED. However, MetS and, specifically, obesity interference on penile hemodynamics is still controversial. AIM To evaluate the impact of independent MetS criteria and obesity on penile duplex Doppler ultrasound (PDDU) parameters in men with ED. METHODS Consecutive patients (n = 212) referred to a unit of PDDU were evaluated for cardiovascular risk factors and MetS (ATP III criteria). Body mass index and body fat percentage (BF%) were calculated. Each patient underwent a PDDU by the same investigator. Data are expressed as mean ± standard deviation, and statistical significance was considered at P level < 0.05. Statistical analysis of clinical, laboratory, and PDDU parameters was performed with SPSS® software. MAIN OUTCOME MEASURES To evaluate the individual power of MetS clusters and obesity as predictive factors for penile hemodynamic changes namely mean peak systolic velocity (mPSV). RESULTS MetS was present in 24.8% of men, and 80.8% of them presented penile hemodynamics alterations, with mPSV significantly lower comparatively to no MetS patients (29.0 vs. 35.4 cm/s, P = 0.004). Multivariate analysis demonstrated that, considering all MetS parameters, only HTA was significantly associated with diminished mPSV. However, after further adjustment for all cardiovascular risk factors, BF% remained the sole independent clinical factor for penile hemodynamics impairment. CONCLUSIONS There is a strong association between MetS and ED, but within MetS criteria, only HTA was independently associated with the deterioration of penile hemodynamics parameters. Although the classical methods of evaluating obesity in MetS were not individually associated with PDDU impairment, BF% represented by itself an excellent predictor of vascular ED.

Differentially expressed angiogenic genes in diabetic erectile tissue — Results from a microarray screening

Diabetes-induced metabolic derangements promote endothelial malfunction, contributing to erectile dysfunction (ED). However, it remains unclear which angiogenic molecular mechanisms are deregulated in diabetic corpus cavernosum (CC). We investigated early and late alterations in cavernosal angiogenic gene expression associated to diabetes. Angiogenic changes were assessed in penile tissue of streptozotocin-induced Wistar rats, in an early (2-week) and established stage (8-week) of diabetes. Differentially expressed genes were identified by microarrays and expression data validated by quantitative real-time PCR (qrt-PCR). At protein level, quantitative immunohistochemistry confirmed the arrays data and dual immunofluorescence for selected alterations and α-smooth muscle actin (α-SMA) identified the cellular location of target proteins. The selected differentially expressed genes were also evaluated in human non-diabetic and diabetic CC by quantitative immunolabeling. At 2-week diabetes there was no differential gene expression between non-diabetic and diabetic CC. At 8-week, 10 genes were found down-regulated in diabetics. The results were validated by qrt-PCR for the insulin-like growth factor-1 (Igf1) and the natriuretic peptide receptor-1 (Npr1) genes. Dual immunofluorescence for IGF-1/ α-SMA showed predominant localization of IGF-1 in SM. NPR-1 expression was diffuse and mostly present in trabecular fibroblasts and SM. Quantitative immunostaining confirmed the decreased expression of both proteins in diabetic tissues. Concordantly, we detected a significant reduction in IGF-1 and NPR-1 protein expressions in human diabetic samples. Microarray analysis identified 10 angiogenic-related molecules deregulated in CC of established diabetes. Among them, IGF-1 and NPR-1 were significantly down-regulated and might result in preventive/therapeutic targets for ED management.

Testosterone, Endothelial Health, and Erectile Function

Experimental and clinical studies have reported that testosterone has a critical role in the maintenance of homeostatic and morphologic corpus cavernosum components, essential for normal erectile physiology. Although the exact mechanisms mediated by testosterone in erectile function are still under investigation, recent research has suggested an important role in the regulation of endothelial cell (EC) biological functions. Besides stimulating the production of EC mediators, testosterone is also thought to promote the vasculogenic reendothelialization process, mediated by bone marrow-derived endothelial progenitor cells. Additionally, testosterone seems to modulate other erectile tissue components, including trabecular smooth muscle cells, nerve fibers, and tunica albuginea structure, all essential for the erectile process. This paper summarizes current data regarding testosterone-induced cellular and molecular mechanisms that regulate penile tissue components, focusing particularly on the role of testosterone in endothelial health and erectile function.

Expression of vascular endothelial growth factor and angiopoietins in human corpus cavernosum.

To evaluate the expression of the angiogenic factors vascular endothelial growth factor (VEGF) and angiopoietins (Ang) 1 and 2, in normal human penile erectile tissue.

Penile corporoplasty with Yachia's technique for Peyronie's disease: Single center experience with 117 patients.

Introduction: Peyronies disease is an acquired penile deformity with a variety of presentations, caused by the formation of fibrous plaques within the tunica albuginea, leading to bio-mechanical and vascular abnormalities. The objective is to investigate the 18 years outcome of patients with Peyronies disease treated with penile corporoplasty (Yachia technique) in our department. Materials and Methods: One hundred and seventeen patients underwent surgical treatment for PD between 1991 and 2009 and were retrospectively evaluated. We used the Levine and Lentings algorithm for surgical treatment. Data was obtained from medical records, clinical evaluation, and telephone interview. Post-operative follow-up was at 6 weeks and 12 months. The mean time of follow-up was 14 months (12-19 months). Main Outcome Measures: Patient demographic, co-morbidities, erectile function, penile curvature, and surgical intervention were documented. The main outcome measures of this study are postoperative complications, surgical purpose, and patients and partners satisfaction rates. Results: Surgical aim was obtained in 106 patients (success rate of 94.6%). Complications occurred in 4.5% of patients, but most of these were mild. At 6 weeks, complete straightening of the penis was achieved in 57 patients (50.9%), and partial straightening which allow sexual intercourse in 49 patients (43.7%). Nine patients report gland hypoesthesia and almost all report subjective perception of penis shortening (0.5 cm to 5 cm). Twenty-two patients developed recurrent deformity at 12 months follow-up, with compromise of sexual intercourse in 7 patients. Patients’ responses to our questionnaire showed that overall 88.4% of the patients and partners were satisfied with the surgical results. Conclusion: According to the results of this long-term, retrospective study, surgical correction, using the Yachia technique, is an excellent option for patients with functional impairment from their Peyronies disease, especially.

Comparative ultrastructural study of human corpus cavernosum during ageing

Erectile Dysfunction (ED), the inability to achieve or maintain an erection of sufficient rigidity for completion of sexual act, is a common condition affecting more than 150 million of men worldwide. This disorder is highly associated with aging, however concomitant pathologies such as hyperlipidemia, hypertension, and diabetes also contribute to ED progression. In the Massachusetts Male Aging Study, age was considered an independent variable strongly associated with ED, showing that the prevalence of this disease increased with age from 38% in the youngest group of men (mean age 40 y.) to almost 70% in the oldest group of men examined (mean age 70 y.). It is well demonstrated that aging leads to changes in the cardiovascular system, which results in a decrease in elasticity due to fibrosis and an increase in stiffness of the arterial system, independently of the effects of concurrent pathologies. Vasculogenic ED is the most prevalent condition, affecting nearly 80% of patients with organic etiology. Small vessels of the penis are very sensitive to structural and functional changes, and small disturbances can conduce to ED. ED is now considered by some authors as synonymous to endothelial dysfunction and an early manifestation of atherosclerosis, being a precursor of systemic vascular disease. Human cavernous tissue is mainly constituted by smooth muscle fibers that surround sinusoid vessels. Corpus cavernosum structural elements act in concert, allowing increase of intra-cavernous arterial flow and smooth muscle relaxation processes which are fundamental to penile erection. The aim of this study was to compare the ultrastructural anatomy of the young and aged human corpus cavernosum, in the absence of additional risk factors.