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

Ursodeoxycholic acid ameliorates erectile dysfunction and corporal fibrosis in diabetic rats by inhibiting the TGF-β1/Smad2 pathway

Corporal tissue fibrosis is critical in diabetes-associated erectile dysfunction. Transforming growth factor-β1/Small mothers against decapentaplegic-2 (TGF-β1/Smad2) contributes to the induction of fibrosis in corporal tissue. Smad7 is accepted as a general negative regulator of Smad signaling, although its role in corporal fibrosis is unknown. Ursodeoxycholic acid (UDCA) is a hydrophilic bile acid used for biliary and liver related disorders and has antifibrotic effects in the liver. This study investigated the effects of UDCA on diabetic erectile dysfunction. Forty-eight male Spraque Dawley rats were divided into six groups: nondiabetic (n = 6), nondiabetic+20 mg/kg UDCA (n = 6), nondiabetic+80 mg/kg UDCA (n = 6), diabetic (n = 10), diabetic+20 mg/kg UDCA (n = 10), diabetic+80 mg/kg UDCA (n = 10). Diabetes was induced by intraperitoneal injection of 60 mg/kg Streptozocin. UDCA (20 and 80 mg/kg/day) or saline was subsequently administered via oral gavage for 56 days. Erectile function was evaluated as measurement of maximum intracavernosal pressure (m-ICP)/mean arterial pressure (MAP) and total ICP/MAP. Corporal tissues were evaluated by Western blotting and Masson's trichrome staining. Electrical stimulation-induced m-ICP/MAP responses were higher in UDCA-treated diabetic rats compared to untreated diabetic rats, respectively (20 mg/kg; 4 V: 0.77 ± 0.11 vs 0.45 ± 0.09, p = 0.0001 and 80 mg/kg; 4 V: 0.78 ± 0.11 vs 0.45 ± 0.09, p = 0.0001) UDCA prevented the increase in phospho-Smad2 and fibronectin protein expressions in diabetic corporal tissue both at 20 mg/kg (p = 0.0002, p = 0.002 respectively) and 80 mg/kg doses (p < 0.0001 for both). Smad7 protein expressions were significantly increased in the UDCA-treated diabetic groups compared to the untreated diabetic group (20 mg/kg: p = 0.0079; 80 mg/kg: p = 0.004). Furthermore, UDCA significantly prevented diabetes-induced increase in collagen (20 mg/kg: p = 0.0172; 80 mg/kg: p = 0.0003) and smooth muscle loss (20 mg/kg: p = 0.044; 80 mg/kg: p = 0.039). In conclusion, UDCA has a potential protective effect on erectile function in diabetic rats by altering fibrotic pathways via inhibition of TGF-β1/Smad2 and activation of Smad7.

Potential Effect of the Circadian Clock on Erectile Dysfunction

The circadian rhythm is an internal timing system, which is generated by circadian clock genes. Because the circadian rhythm regulates numerous cellular, behavioral, and physiological processes, organisms have evolved with intrinsic biological rhythms to adapt the daily environmental changes. A variety of pathological events occur at specific times, while disturbed rhythms can lead to metabolic syndrome, vascular dysfunction, inflammatory disorders, and cancer. Therefore, the circadian clock is considered closely related to various diseases. Recently, accumulated data have shown that the penis is regulated by the circadian clock, while erectile function is impaired by an altered sleep-wake cycle. The circadian rhythm appears to be a novel therapeutic target for preventing and managing erectile dysfunction (ED), although research is still progressing. In this review, we briefly summarize the superficial interactions between the circadian clock and erectile function, while focusing on how disturbed rhythms contribute to risk factors of ED. These risk factors include NO/cGMP pathway, atherosclerosis, diabetes mellitus, lipid abnormalities, testosterone deficiency, as well as dysfunction of endothelial and smooth muscle cells. On the basis of recent findings, we discuss the potential role of the circadian clock for future therapeutic strategies on ED, although further relevant research needs to be performed.

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.

Dyslipidemia Is a Major Factor in Stem Cell Damage Induced by Uncontrolled Long-Term Type 2 Diabetes and Obesity in the Rat, as Suggested by the Effects on Stem Cell Culture

BACKGROUND

Previous work showed that muscle-derived stem cells (MDSCs) exposed long-term to the milieu of uncontrolled type 2 diabetes (UC-T2D) in male obese Zucker (OZ) rats, were unable to correct the associated erectile dysfunction and the underlying histopathology when implanted into the corpora cavernosa, and were also imprinted with a noxious gene global transcriptional signature (gene-GTS), suggesting that this may interfere with their use as autografts in stem cell therapy.

AIM

To ascertain the respective contributions of dyslipidemia and hyperglycemia to this MDSC damage, clarify its mechanism, and design a bioassay to identify the damaged stem cells.

METHODS

Early diabetes MDSCs and late diabetes MDSCs were respectively isolated from nearly normal young OZ rats and moderately hyperglycemic and severely dyslipidemic/obese aged rats with erectile dysfunction. Monolayer cultures of early diabetic MDSCs were incubated 4 days in DMEM/10% fetal calf serum + or - aged OZ or lean Zucker serum from non-diabetic lean Zucker rats (0.5-5%) or with soluble palmitic acid (PA) (0.5-2 mM), cholesterol (CHOL) (50-400 mg/dL), or glucose (10-25 mM).

MAIN OUTCOME MEASURE

Fat infiltration was estimated by Oil red O, apoptosis by TUNEL, protein expression by Western blots, and gene-GTS and microRNA (miR)-GTS were determined in these stem cells' RNA.

RESULTS

Aged OZ serum caused fat infiltration, apoptosis, myostatin overexpression, and impaired differentiation. Some of these changes, and also a proliferation decrease occurred with PA and CHOL. The gene-GTS changes by OZ serum did not resemble the in vivo changes, but some occurred with PA and CHOL. The miR-GTS changes by OZ serum, PA, and CHOL resembled most of the in vivo changes. Hyperglycemia did not replicate most alterations.

CLINICAL IMPLICATIONS

MDSCs may be damaged in long-term UC-T2D/obese patients and be ineffective in autologous human stem cell therapy, which may be prevented by excluding the damaged MDSCs.

STRENGTH & LIMITATIONS

The in vitro test of MDSCs is innovative and fast to define dyslipidemic factors inducing stem cell damage, its mechanism, prevention, and counteraction. Confirmation is required in other T2D/obesity rat models and stem cells (including human), as well as miR-GTS biomarker validation as a stem cell damage biomarker.

CONCLUSION

Serum from long-term UC-T2D/obese rats or dyslipidemic factors induces a noxious phenotype and miR-GTS on normal MDSCs, which may lead in vivo to the repair inefficacy of late diabetic MDSCs. This suggests that autograft therapy with MDSCs in long-term UT-T2D obese patients may be ineffective, albeit this may be predictable by prior stem cell miR-GTS tests. Masouminia M, Gelfand R, Kovanecz I, et al. Dyslipidemia Is a Major Factor in Stem Cell Damage Induced by Uncontrolled Long-Term Type 2 Diabetes and Obesity in the Rat, as Suggested by the Effects on Stem Cell Culture. J Sex Med 2018;15:1678-1697.

Hypoxia-Induced Phenotypic Transformation of Corpus Cavernosum Smooth Muscle Cells After Cavernous Nerve Crush Injury by Down-Regulating P38 Mitogen-Activated Protein Kinase Expression

INTRODUCTION

Cavernosal nerve (CN) injury is commonly caused by radical prostatectomy surgery, and it might directly lead to erectile dysfunction (ED). Currently, the role of mitogen-activated protein kinase (MAPK) family proteins in phenotypic transformation of corpus cavernosum smooth muscle cell (CCSMC) after CNs injury is poorly understood.

AIM

To investigate the role of p38 MAPK in hypoxia-induced phenotypic transformation of CCSMCs after CN injury.

METHODS

In total, 20 Sprague-Dawley rats (male and 8 weeks of age) were randomly divided into 2 groups, including a sham group and CNCI group. In the sham group, rats were sham-operated by identifying 2 CNs without causing direct damage to the CNs. In the CNCI group, rats were subjected to bilateral CN crush injury. CCSMCs were isolated from the normal corpus cavernosum tissues of the Sprague-Dawley rat and then cultured in 21% or 1% O₂ concentration context for 48 hours.

MAIN OUTCOME MEASURES

Intracavernous pressure/mean arterial pressure were analyzed to measure erectile response. The impact of hypoxia on penile pathology, as well as the expression of extracellular signal-regulated kinases, the c-Jun NH2-terminal kinase, and p38 MAPK, were analyzed.

RESULTS

Compared with the sham group, the intracavernous pressure/mean arterial pressure rate and α-smooth muscle actin expression of CNCI group were decreased significantly (P = .0001; P = .016, respectively), but vimentin expression was significantly increased (P = .023). Phosphorylated p38 level in CNCI group was decreased significantly (P = .017; sham: 0.17 ± 0.005; CNCI: 0.14 ± 0.02). The CCSMCs in the normoxia group were long fusiform, whereas the morphology of CCSMCs in the hypoxia group became hypertrophic. After hypoxia for 48 hours, the expression of α-smooth muscle actin and phosphorylated p38 MAPK was decreased significantly (P = .01; P = .024, normoxia: 0.66 ± 0.18, hypoxia: 0.26 ± 0.08, respectively), and the expression of hypoxia-inducible factor-1α and collagen I was increased significantly in hypoxia group (P = .04; P = .012, respectively).

CONCLUSIONS

Hypoxia induced the phenotypic transformation of CCSMCs after CNCI might be associated with the downregulation of phosphorylated p38 MAPK. Chen S, Huang X, Kong X, et al. Hypoxia-Induced Phenotypic Transformation of Corpus Cavernosum Smooth Muscle Cells After Cavernous Nerve Crush Injury by Down-Regulating p38 Mitogen-Activated Protein Kinase Expression. Sex Med 2019;7:433-440.

Transplantation of Human Urine-Derived Stem Cells Ameliorates Erectile Function and Cavernosal Endothelial Function by Promoting Autophagy of Corpus Cavernosal Endothelial Cells in Diabetic Erectile Dysfunction Rats

Aims

Cavernosal endothelial dysfunction is one of the factors in developing diabetic erectile dysfunction (DED), but the mechanism of cavernosal endothelial dysfunction is unclear. The present study is aimed at determining the contribution of autophagy in cavernosal endothelial dysfunction of DED rats and explaining the therapeutic effect of urine-derived stem cells (USCs).

Methods

After rat corpus cavernosal vascular endothelial cells (CCECs) were isolated and cultured in vitro, CCECs were treated with advanced glycation end products (AGEs) to mimic the diabetic situation. Autophagy flux, proliferation, and apoptosis of CCECs were determined by mRFP-GFP-LC3 adenovirus infection combined with fluorescence observation and western blot analysis. USCs were isolated from the urine of six healthy male donors, and coculture systems of USCs and CCECs were developed to assess the protective effect of USCs for CCECs in vitro. The contribution of autophagy to the cellular damage in CCECs was evaluated by the autophagic inhibitor, 3-methyladenine (3-MA). Then, DED rats were induced by streptozotocin (50 mg/kg) and screened by apomorphine test (100 μg/kg). In DED rats, USCs or PBS as vehicle was administrated by intracavernous injection (n = 15 per group), and another 15 normal rats served as normal controls. Four weeks after injection, erectile function was evaluated by measuring the intracavernosal pressure (ICP) and mean arterial pressure (MAP). Cavernosal endothelial function and autophagic activity were examined by western blot, immunofluorescence, and transmission electron microscopy.

Results

In vitro, AGE-treated CCECs displayed fewer LC3 puncta formation and expressed less LC3-II, Beclin1, and PCNA but expressed more p62 and cleaved-caspase3 than controls (p < 0.05). Coculture of USCs with CCECs demonstrated that USCs were able to protect CCECs from AGE-induced autophagic dysfunction and cellular damage, which could be abolished by 3-MA (p < 0.05). DED rats showed lower ratio of ICP/MAP, reduced expression of endothelial markers, and fewer autophagic vacuoles in the cavernosal endothelium when compared with normal rats (p < 0.05). Intracavernous injection of USCs improved erectile function and cavernosal endothelial function of DED rats (p < 0.05). Most importantly, our data showed that the repaired erectile function and cavernosal endothelial function were the result of restored autophagic activity of the cavernosal endothelium in DED rats (p < 0.05).

Conclusions

Impaired autophagy is involved in the cavernosal endothelial dysfunction and erectile dysfunction of DED rats. Intracavernous injection of USCs upregulates autophagic activity in the cavernosal endothelium, contributing to ameliorating cavernosal endothelial dysfunction and finally improving the erectile dysfunction induced by diabetes.

Stem Cells from a Female Rat Model of Type 2 Diabetes/Obesity and Stress Urinary Incontinence Are Damaged by In Vitro Exposure to its Dyslipidemic Serum, Predicting Inadequate Repair Capacity In Vivo

Female stress urinary incontinence (FSUI) is prevalent in women with type 2 diabetes/obesity (T2D/O), and treatment is not optimal. Autograph stem cell therapy surprisingly has poor efficacy. In the male rat model of T2D/O, it was demonstrated that epigenetic changes, triggered by long-term exposure to the dyslipidemic milieu, led to abnormal global transcriptional signatures (GTS) of genes and microRNAs (miR), and impaired the repair capacity of muscle-derived stem cells (MDSC). This was mimicked in vitro by treatment of MDSC with dyslipidemic serum or lipid factors. The current study aimed to predict whether these changes also occur in stem cells from female 12 weeks old T2D/O rats, a model of FSUI. MDSCs from T2D/O (ZF4-SC) and normal female rats (ZL4-SC) were treated in vitro with either dyslipidemic serum (ZFS) from late T2D/O 24 weeks old female Zucker fatty (ZF) rats, or normal serum (ZLS) from 24 weeks old female Zucker lean (ZL) rats, for 4 days and subjected to assays for fat deposition, apoptosis, scratch closing, myostatin, interleukin-6, and miR-GTS. The dyslipidemic ZFS affected both female stem cells more severely than in the male MDSC, with some gender-specific differences in miR-GTS. The changes in miR-GTS and myostatin/interleukin-6 balance may predict in vivo noxious effects of the T2D/O milieu that might impair autograft stem cell (SC) therapy for FSUI, but this requires future studies.

Liraglutide inhibited AGEs induced coronary smooth muscle cell phenotypic transition through inhibiting the NF-κB signal pathway

Vascular smooth muscle cell (VSMC) phenotype transition is involved in diabetes-associated cardiovascular diseases. The mechanism of VSMCs phenotypic transition in T2DM was still unclear. Rat coronary artery SMCs were pretreated with liraglutide alone, liraglutide and H89(a PKA inhibitor), neutralizing anti-RAGE antibody or the antioxidant pyrrolidine dithiocarbamate (PDTC; a nuclear factor-κB (NF-κB) inhibitor), followed by treatment with AGE. The morphological change of the SMCs was observed. We also observed the α-actin positive myofilaments and F-actin distribution in SMC through immunofluorescence microscopy. Smooth muscle myosin heavy chain 11(MYH11), α-smooth muscle actin (α-SMA) and myocardin protein expression were detected by Western blot. Collagen I productionS and NF-κB nuclear translocation were also investigated. AGEs induced a transition of SMC from contractile to synthetic phenotype, which was associated with decreased SMC differentiation markers such as α-SMA, MYH11 and myocardin by activating the NF-κB pathway. AGE also increased collagen I production and secretion by SMCs. Liraglutide inhibited AGEs induced SM phenotypic transition and down-regulation of α-SMA, MYH11 and myocardin. Liraglutide also inhibited AGEs induced NF-κB pathway activation and collagen I production. Pretreatment with liraglutide and H89 together did not exhibit this inhibitory effect as mentioned above. Blockade of RAGE in SMCs with neutralizing antibody inhibited AGEs induced phenotypic transition of SMC, and up-regulated α-SMA and MYH11 expression. Liraglutide inhibited AGE induced SMC phenotypic transition, increased SMC contractile markers expression, and decreased collagen production through down-regulation of myocardin, inhibition of NF-κB pathway, and activation of PKA signaling pathway.

Low-intensity shockwave therapy for erectile dysfunction in kidney transplant recipients. A prospective, randomized, double blinded, sham-controlled study with evaluation by penile Doppler ultrasonography

OBJECTIVES

To study the efficacy of Low intensity Extracorporeal Shockwave Therapy (Li- ESWT) for the treatment of erectile dysfunction (ED) in kidney transplanted men.

METHODS

Twenty men (mean age = 53.7 years) were selected. This was a double-blinded, prospective, randomized, sham-controlled trial. The ESWT protocol was based in a 2 treatment sessions per week for 3 weeks. The sham treatment was performed using the same device replacing the effective probe for one that emits zero energy. Baseline and follow-up assessment was performed with International Index of Erectile Function Questionnaire (IIEF) score and Erection Hardness Score (EHS) after 1, 4 and 12 months. Penile Doppler was performed before and after treatment.

RESULTS

A total of 20 patients were recruited, 10 patients in each group. Baseline scores were similar. The mean EHS in after 1 month were 2.5 ± 0.85 (Li-EWST) and 2.4 ± 0.7 (Sham therapy), p = 0.724 . After 4 months it was 2.4 ± 0.7 and 2.6 ± 0.84, p = 0,0004 (between the moments) . The baseline IIEF score was 14.9 ± 3(Sham Theraphy) and 10.9 ± 5.1 (Li-EWST). The mean IIEF score after 1 month was 15.6 ± 6.1 (Li-EWST) and 16.6 ± 5.4 (Sham therapy). The mean IIEF score after 4 months was 17.2 ± 5.7 (Li-EWST) and 16.5 ± 5 (Sham therapy), p < 0.0001 (between the moments). IIEF score improvement was higher than 5 in 70% (ranged from 0-10) and in 10% (ranged from 1-14) in Li-ESWT and Sham groups, respectively. The mean change in IIEF score after 12 months was 4.8 in Li-ESWT group .Penile Doppler parameters were similar between groups and did not present improvements.

CONCLUSIONS

Li-ESWT is a treatment with clinical efficacy. Despite evidences suggesting neoagiogenesis, our short protocol had no impact in penile Doppler parameters.

Penile alterations at early stage of type 1 diabetes in rats

Objective

Diabetes affects the erectile function significantly. However, the penile alterations in the early stage of diabetes in experimental animal models have not been well studied. We examined the changes of the penis and its main erectile components in diabetic rats.

Materials and methods

Male Sprague-Dawley rats were divided into 2 groups: streptozotocin (STZ)-induced diabetics and age-matched controls. Three or nine weeks after diabetes induction, the penis was removed for immunohistochemical staining of smooth muscle and neuronal nitric oxide synthase (nNOS) in midshaft penile tissues. The cross-sectional areas of the whole midshaft penis and the corpora cavernosa were quantified. The smooth muscle in the corpora cavernosa and nNOS in the dorsal nerves were quantified.

Results

The weight, but not the length, of the penis was lower in diabetics. The cross-sectional areas of the total midshaft penis and the corpora cavernosa were lower in diabetic rats compared with controls 9 weeks, but not 3 weeks after diabetes induction. The cross-sectional area of smooth muscle in the corpora cavernosa as percentage of the overall area of the corpora cavernosa was lower in diabetic rats than in controls 9 weeks, but not 3 weeks after diabetes induction. Percentage change of nNOS in dorsal nerves was similar at 3 weeks, and has a decreased trend at 9 weeks in diabetic rats compared with controls.

Conclusions

Diabetes causes temporal alterations in the penis, and the significant changes in STZ rat model begin 3-9 weeks after induction. Further studies on the reversibility of the observed changes are warranted.

Implanted Muscle-Derived Stem Cells Ameliorate Erectile Dysfunction in a Rat Model of Type 2 Diabetes, but Their Repair Capacity Is Impaired by Their Prior Exposure to the Diabetic Milieu

INTRODUCTION

Muscle-derived stem cells (MDSCs) and other SCs implanted into the penile corpora cavernosa ameliorate erectile dysfunction in type 1 diabetic rat models by replenishing lost corporal smooth muscle cells (SMCs) and decreasing fibrosis. However, there are no conclusive data from models of type 2 diabetes (T2D) and obesity.

AIM

To determine whether MDSCs from obese Zucker (OZ) rats with T2D at an early stage of diabetes (early diabetic SCs isolated and cultured in low-glucose medium [ED-SCs]) counteract corporal veno-occlusive dysfunction and corporal SMC loss or lipo-fibrosis when implanted in OZ rats at a late stage of diabetes and whether MDSCs from these OZ rats with late diabetes (late diabetic SCs isolated and cultured in high-glucose medium [LD-SC]) differ from ED-SCs in gene transcriptional phenotype and repair capacity.

METHODS

ED-SCs and LD-SCs were compared by DNA microarray assays, and ED-SCs were incubated in vitro under high-glucose conditions (ED-HG-SC). These three MDSC types were injected into the corpora cavernosa of OZ rats with late diabetes (OZ/ED, OZ/LD, and OZ/ED-HG rats, respectively). Untreated OZ and non-diabetic lean Zucker rats functioned as controls. Two months later, rats were subjected to cavernosometry and the penile shaft and corporal tissues were subjected to histopathology and DNA microarray assays.

MAIN OUTCOME MEASURES

In vivo erectile dysfunction assessment by Dynamic Infusion Cavernosometry followed by histopathology marker analysis of the penile tissues.

RESULTS

Implanted ED-SCs and ED-HG-SCs improved corporal veno-occlusive dysfunction, counteracted corporal decreases in the ratio of SMCs to collagen and fat infiltration in rats with long-term T2D, and upregulated neuronal and endothelial nitric oxide. LD-SCs acquired an inflammatory, pro-fibrotic, oxidative, and dyslipidemic transcriptional phenotype and failed to repair the corporal tissue.

CONCLUSION

MDSCs from pre-diabetic rats injected into the corpora cavernosa of rats with long-term T2D improve corporal veno-occlusive dysfunction and the underlying histopathology. In contrast, MDSCs from rats with long-term uncontrolled T2D are imprinted by the hyperglycemic and dyslipidemic milieu with a noxious phenotype associated with an impaired tissue repair capacity. SCs affected by diabetes could lack tissue repair efficacy as autografts and should be reprogrammed in vitro or substituted by SCs from allogenic non-diabetic sources.

The platelet-derived growth factor receptor/STAT3 signaling pathway regulates the phenotypic transition of corpus cavernosum smooth muscle in rats

Erectile dysfunction (ED) is a common clinical disease that is difficult to treat. We previously found that hypoxia modulates the phenotype of primary corpus cavernosum smooth muscle cells (CCSMCs) in rats, but the underlying molecular mechanism is still unknown. Platelet-derived growth factor receptor (PDGFR)-related signaling pathways are correlated with cell phenotypic transition, but research has been focused more on vascular smooth muscle and tracheal smooth muscle and less on CCSMCs. Here, we investigated the role of PDGFR-related signaling pathways in penile CCSMCs, which were successfully isolated from rats and cultured in vitro. PDGF-BB at 5, 10, or 20 ng/ml altered CCSMC morphology from the original elongated, spindle shape to a broader shape and promoted the synthetic phenotype and expression of the related proteins vimentin and collagen-I, while inhibiting the contractile phenotype and expression of the related proteins smooth muscle (SM) α-actin (α-SMA) and desmin. Inhibition of PDGFR activity via siRNA or the PDGFR inhibitor crenolanib inhibited vimentin and collagen-I expression, increased α-SMA and desmin expression, and considerably inhibited serine-threonine protein kinase (AKT) and signal transducer and activator of transcription 3 (STAT3) phosphorylation. STAT3 knockdown promoted the contractile phenotype, inhibited vimentin and collagen-I expression, and increased α-SMA and desmin expression, whereas AKT knockdown did not affect phenotype-associated proteins. STAT3 overexpression in CCSMC cells weakened the suppressive effect of PDGFR inhibition on the morphology and phenotypic transformation induced by PDGF-BB. Through activation of the PDGFR/STAT3 signaling pathway, PDGF promoted the synthetic phenotype transition; thus, regulation of this pathway might contribute to ED therapy.

Combination of low-energy shock-wave therapy and bone marrow mesenchymal stem cell transplantation to improve the erectile function of diabetic rats

Stem cell transplantation and low-energy shock-wave therapy (LESWT) have emerged as potential and effective treatment protocols for diabetic erectile dysfunction. During the tracking of transplanted stem cells in diabetic erectile dysfunction models, the number of visible stem cells was rather low and decreased quickly. LESWT could recruit endogenous stem cells to the cavernous body and improve the microenvironment in diabetic cavernous tissue. Thus, we deduced that LESWT might benefit transplanted stem cell survival and improve the effects of stem cell transplantation. In this research, 42 streptozotocin-induced diabetic rats were randomized into four groups: the diabetic group (n = 6), the LESWT group (n = 6), the bone marrow-derived mesenchymal stem cell (BMSC) transplantation group (n = 15), and the combination of LESWT and BMSC transplantation group (n = 15). One and three days after BMSC transplantation, three rats were randomly chosen to observe the survival numbers of BMSCs in the cavernous body. Four weeks after BMSC transplantation, the following parameters were assessed: the surviving number of transplanted BMSCs in the cavernous tissue, erectile function, real-time polymerase chain reaction, and penile immunohistochemical assessment. Our research found that LESWT favored the survival of transplanted BMSCs in the cavernous body, which might be related to increased stromal cell-derived factor-1 expression and the enhancement of angiogenesis in the diabetic cavernous tissue. The combination of LESWT and BMSC transplantation could improve the erectile function of diabetic erectile function rats more effectively than LESWT or BMSC transplantation performed alone.

Constitutive NOS uncoupling and NADPH oxidase upregulation in the penis of type 2 diabetic men with erectile dysfunction

Erectile dysfunction (ED) associated with type 2 diabetes mellitus (T2DM) involves dysfunctional nitric oxide (NO) signaling and increased oxidative stress in the penis. However, the mechanisms of endothelial NO synthase (eNOS) and neuronal NO synthase (nNOS) dysregulation, and the sources of oxidative stress, are not well defined, particularly at the human level. The objective of this study was to define whether uncoupled eNOS and nNOS, and NADPH oxidase upregulation, contribute to the pathogenesis of ED in T2DM men. Penile erectile tissue was obtained from 9 T2DM patients with ED who underwent penile prosthesis surgery for ED, and from six control patients without T2DM or ED who underwent penectomy for penile cancer. The dimer-to-monomer protein expression ratio, an indicator of uncoupling for both eNOS and nNOS, total protein expressions of eNOS and nNOS, as well as protein expressions of NADPH oxidase catalytic subunit gp91phox (an enzymatic source of oxidative stress) and 4-hydroxy-2-nonenal [4-HNE] and nitrotyrosine (markers of oxidative stress) were measured by western blot in this tissue. In the erectile tissue of T2DM men, eNOS and nNOS uncoupling and protein expressions of NADPH oxidase subunit gp91phox, 4-HNE- and nitrotyrosine-modified proteins were significantly (p < 0.05) increased compared to control values. Total eNOS and nNOS protein expressions were not significantly different between the groups. In conclusion, mechanisms of T2DM-associated ED in the human penis may involve uncoupled eNOS and nNOS and NADPH oxidase upregulation. Our description of molecular factors contributing to the pathogenesis of T2DM-associated ED at the human level is relevant to advancing clinically therapeutic approaches to restore erectile function in T2DM patients.

Basic Science Evidence for the Link Between Erectile Dysfunction and Cardiometabolic Dysfunction

INTRODUCTION

Although clinical evidence supports an association between cardiovascular/metabolic diseases (CVMD) and erectile dysfunction (ED), scientific evidence for this link is incompletely elucidated.

AIM

This study aims to provide scientific evidence for the link between CVMD and ED.

METHODS

In this White Paper, the Basic Science Committee of the Sexual Medicine Society of North America assessed the current literature on basic scientific support for a mechanistic link between ED and CVMD, and deficiencies in this regard with a critical assessment of current preclinical models of disease.

RESULTS

A link exists between ED and CVMD on several grounds: the endothelium (endothelium-derived nitric oxide and oxidative stress imbalance); smooth muscle (SM) (SM abundance and altered molecular regulation of SM contractility); autonomic innervation (autonomic neuropathy and decreased neuronal-derived nitric oxide); hormones (impaired testosterone release and actions); and metabolics (hyperlipidemia, advanced glycation end product formation).

CONCLUSION

Basic science evidence supports the link between ED and CVMD. The Committee also highlighted gaps in knowledge and provided recommendations for guiding further scientific study defining this risk relationship. This endeavor serves to develop novel strategic directions for therapeutic interventions.

Low-intensity Pulsed Ultrasound Improves Erectile Function in Streptozotocin-induced Type I Diabetic Rats

OBJECTIVE

To investigate the effect of low-intensity pulsed ultrasound (LIPUS) as a treatment for erectile dysfunction (ED) in a rat model of type I diabetes mellitus (DM) induced by streptozotocin (STZ).

MATERIALS AND METHODS

Seventy male Sprague-Dawley rats were randomly assigned to 2 cohorts: a normal control (NC) group and an STZ-induced DM group, which was further subdivided into DM, DM+LIPUS 100, DM+LIPUS 200, and DM+LIPUS 300 groups and a DM+LESWT (low-energy shock wave therapy) 300 positive control group. Animals in the LIPUS subgroups were treated at different energy levels (100, 200, and 300 mW/cm(2)) for 3 minutes, and animals in the LESWT group received 300 shocks at 0.09 mJ/mm(2). All procedures were repeated 3 times per week for 2 weeks. After a 2-week wash-out period, intracavernous pressure (ICP) was measured; the midpenile region was examined histologically; and VEGF, αSMA, eNOS, and nNOS expression, and activity of the TGF-β1/Smad/CTGF signaling pathway were examined in penile tissue by Western blot analysis.

RESULTS

LIPUS therapy significantly improved erectile function in diabetic rats, as evidenced by enhanced ICP levels, increased endothelial and smooth muscle content, a higher collagen I/collagen III ratio, increased quantity of elastic fibers, and elevated eNOS and nNOS expression. Interestingly, LIPUS was also associated with downregulation of the TGF-β1/Smad/CTGF signaling pathway in penile tissue, whose activation is correlated with ED pathology.

CONCLUSION

LIPUS therapy improved erectile function and reversed pathologic changes in penile tissue of STZ-induced diabetic rats. LIPUS therapy has potential as a noninvasive therapy for diabetic ED in the clinic.

Effects of Nigella sativa L. seed oil on intima-media thickness and Bax and Caspase 3 expression in diabetic rat aorta

OBJECTIVE

Hyperglycaemia is an important risk factor for the development and progression of the macrovascular and microvascular complications that occur in diabetes. The expression of apoptotic markers in the aortic medial layer of diabetic rats and the effects of N. sativa L. seed oil on the expression of these markers were investigated in this study.

METHODS

Four-month-old adult female Wistar rats (n=21) were divided into 3 groups: Group 1, control; Group 2, diabetes and Group 3, diabetes+N. sativa L. seed oil. Group 3 received 0.2 mg/kg/day N. sativa L. seed (black cumin) oil intraperitoneally 6 days per week for 30 days. At the end of the experiment, abdominal and thoracic aortas of all animals were collected and fixed in 10% formalin solution. Then, 5-μm-thick sections were stained with Verhoeff-Van Gieson stain to evaluate Bax and Caspase 3 expression. Tunica intima-media thickness was measured using the stained sections.

RESULTS

There were no significant differences in abdominal or thoracic aortic intima-media thickness among the 3 groups. However, there were significant differences in Bax and Caspase 3 expression in the tunica media of the thoracic and abdominal aortas between Group 1 and Group 2 (p<0.05) and between Group 2 and Group 3 (p<0.05) evaluated with the Kruskal-Wallis and Mann-Whitney U tests.

CONCLUSION

It is understood that N. sativa L. seed oil is effective against diabetes. N. sativa L. seed oil is a plant material and has value for further investigation to develop diabetes treatment strategies for preventing apoptosis in vascular structures.

Low-dose spironolactone reduces plasma fibulin-1 levels in patients with type 2 diabetes and resistant hypertension

Diabetic patients with hypertension are at particularly high risk of vascular damage and consequently cardiovascular and renal disease. Fibulin-1, an extracellular matrix glycoprotein, is increased in arterial tissue and plasma from individuals with type 2 diabetes. This study aimed to evaluate whether antihypertensive treatment with spironolactone changes plasma fibulin-1 levels. In a multicenter, double-blind, randomized, placebo-controlled study, 119 patients with type 2 diabetes and resistant hypertension were included. A dose of spironolactone 25 mg or matching placebo was added to previous treatment at randomization. Blood pressure (BP) and plasma fibulin-1 were measured at baseline and at 16 weeks follow-up. Overall, 112 patients completed the study. All measures of BP were reduced in the spironolactone group at follow-up. Plasma fibulin-1 was significantly reduced after spironolactone treatment (P=0.009), but increased after placebo (P=0.017). Baseline plasma fibulin-1 correlated with BP and estimated glomerular filtration rate. Increased levels of plasma fibulin-1 (P=0.004) were observed in diabetic participants reporting erectile dysfunction as compared with participants who did not. Treatment with low-dose spironolactone reduced plasma fibulin-1 levels in patients with type 2 diabetes and resistant hypertension. This supports the hypothesis that the antihypertensive effect of the mineralocorticoid receptor blocker in part may be due to regression of vascular remodeling.

Myocardin restores erectile function in diabetic rats: phenotypic modulation of corpus cavernosum smooth muscle cells

This study aimed to investigate whether gene transfer of myocardin to the penis of diabetic rats can modulate corpus cavernosum smooth muscle (CCSM) cells phenotype and restore erectile function. Five normal control rats, and 22 diabetic rats were randomly divided into four groups: rats transfected with adCMV-myocardin (N = 6), treated with empty vector (N = 6), injected with medium (N = 5), and sham-operated rats (N = 5). The erectile response was measured 7 days after transfection. The percent of smooth muscle and the expressions of SMα-actin, smooth muscle myosin heavy chain (SMMHC), calponin were evaluated. The increases in intracorporal pressure(ICP)/mean arterial pressure and total ICP in response to nerve stimulation in the adCMV-myocardin treated rats were significantly greater than those in the empty vector (P < 0.001 and P < 0.001), medium only (P < 0.001 and P < 0.001), and sham-operated rats (P < 0.001 and P < 0.001). The suppressed expressions of SMα-actin, SMMHC and calponin were completely restored, and the amount of smooth muscle in diabetic rats were not restored after treatment. It is concluded that myocardin ameliorated erectile responses in diabetic rats mainly via promoting phenotypic modulation of CCSM cells from a proliferative to a contractile state.

Sinusoidal constriction and vascular hypertrophy in the diabetes-induced rabbit penis

OBJECTIVE

To assess the morphological changes of penile vascular structures and the corpus cavernosum area in alloxan-induced diabetic rabbits.

MATERIALS AND METHODS

Twenty male rabbits (2 months old) were divided into two groups with 10 rabbits each, the control group (CG) and the diabetic group (DG). The animals from DG received an intravenous injection of alloxan (100mg/kg) to induce the diabetes. Ten weeks after the induction of diabetes, all animals were euthanized. Two fragments of the penile shaft were harvested and samples were processed and paraffin embedded. Sections (5 µm) were cut and stained for histological and immunohistochemical markers.

RESULTS

Nuclear protrusion toward the lumen, and cytoplasmic vacuolization were observed in the tunica intima of the dorsal artery of the penis in DG. The thicknesses of the tunica media increased significantly in DG (p = 0.0350). It was also observed a significant increase in the area of the tunica media (p = 0.0179). There was no significant change in smooth muscle cell density in the tunica media of the dorsal artery of the penis (p = 0.0855). The collagen fiber pattern of the tunica adventitia of the dorsal artery of the penis was different between the control and diabetic groups. There was a significant decrease in the area occupied by the cavernous sinuses in DG (p = 0.0013).

CONCLUSION

Alloxan-induced diabetes mellitus in rabbits promotes important changes in penile vascular structures, thereby decreasing blood supply and affecting penile hemodynamics, leading to erectile dysfunction.

Effect of chronic low-dose tadalafil on penile cavernous tissues in diabetic rats

OBJECTIVE

To assess the effect of chronic low-dose administration of tadalafil (Td) on penile cavernous tissue in induced diabetic rats.

METHODS

The study investigaged 48 adult male albino rats, comprising a control group, sham controls, streptozotocin-induced diabetic rats, and induced diabetic rats that received Td low-dose daily (0.09 mg/200 g weight) for 2 months. The rats were euthanized 1 day after the last dose. Cavernous tissues were subjected to histologic, immunohistochemical, morphometric studies, and measurement of intracavernosal pressure and mean arterial pressure in anesthetized rats.

RESULTS

Diabetic rats demonstrated dilated cavernous spaces, smooth muscles with heterochromatic nuclei, degenerated mitochondria, vacuolated cytoplasm, and negative smooth muscle immunoreactivity. Nerve fibers demonstrated a thick myelin sheath and intra-axonal edema, where blood capillaries exhibited thick basement membrane. Diabetic rats on Td showed improved cavernous organization with significant morphometric increases in the area percentage of smooth muscles and elastic tissue and a significant decrease of fibrous tissue. The Td-treated group showed enhanced erectile function (intracavernosal pressure/mean arterial pressure) at 0.3, 0.5, 1, 3, and 5 Hz compared with diabetic group values at the respective frequencies (P <.05) that approached control values.

CONCLUSION

Chronic low-dose administration of Td in diabetic rats is associated with substantial improvement of the structure of penile cavernous tissue, with increased smooth muscles and elastic tissue, decreased fibrous tissue, and functional enhancement of the erectile function. This raises the idea that the change in penile architecture with Td treatment improves erectile function beyond its half-life and its direct pharmacologic action on phosphodiesterase type 5.

Evaluation of the effect of different doses of low energy shock wave therapy on the erectile function of streptozotocin (STZ)-induced diabetic rats

To investigate the therapeutic effect of different doses of low energy shock wave therapy (LESWT) on the erectile dysfunction (ED) in streptozotocin (STZ) induced diabetic rats. SD rats (n = 75) were randomly divided into 5 groups (normal control, diabetic control, 3 different dose LESWT treated diabetic groups). Diabetic rats were induced by intra-peritoneal injection of STZ (60 mg/kg) and rats with fasting blood glucose ≥ 300 mg/dL were selected as diabetic models. Twelve weeks later, different doses of LESWT (100, 200 and 300 shocks each time) treatment on penises were used to treat ED (7.33 MPa, 2 shocks/s) three times a week for two weeks. The erectile function was evaluated by intracavernous pressure (ICP) after 1 week washout period. Then the penises were harvested for histological study. The results showed LESWT could significantly improve the erectile function of diabetic rats, increase smooth muscle and endothelial contents, up-regulate the expression of α-SMA, vWF, nNOS and VEGF, and down- regulate the expression of RAGE in corpus cavernosum. The therapeutic effect might relate to treatment dose positively, and the maximal therapeutic effect was noted in the LESWT300 group. Consequently, 300 shocks each time might be the ideal LESWT dose for diabetic ED treatment.

Characterization of corpus cavernosum smooth muscle cell phenotype in diabetic rats with erectile dysfunction

Phenotypic modulation from a contractile to a proliferative state within vascular smooth muscle cells has a critical role in the pathogenesis of a variety of cardiovascular diseases. To investigate the characterization of corpus cavernosum smooth muscle cell phenotype in diabetic rats with erectile dysfunction, a group of Sprague-Dawley rats (n=30) were induced by intraperitoneal injection of streptozotocin (60 mg kg(-1)) and screened by subcutaneous injection of apomorphine (100 μg kg(-1)) for the measurement and comparison of the penile erections, and then three different groups were defined. Primary corpus cavernosum smooth muscle cells were cultured and passaged. The cavernous tissue segments were subjected to quantitative real-time polymerase chain reaction to determine the expressions of smooth muscle α-actin (SMA), SM myosin heavy chain (SMMHC), smoothelin, calponin and myocardin. Cell contractility in vitro and western blot analysis of SMA and SMMHC in the cavernous tissues and cells were determined. Compared with the control group (n=8) and the diabetes mellitus group (n=5), the expressions of SMA, calponin, SMMHC, smoothelin and myocardin mRNA were decreased in the cavernous tissues in rats of the diabetic erectile dysfunction group (n=15; P=0.001 and 0.02, P=0.014 and 0.012, both P<0.001, P=0.005 and <0.001, P=0.003 and 0.035, respectively). The levels of SMA and SMMHC proteins showed a significant decrease in cavernous tissues and cultured cells in rats of the diabetic erectile dysfunction group. Cells of the diabetic erectile dysfunction group exhibited significantly less contractility compared with those of other groups (P<0.001). Corpus cavernosum SM cell possesses the ability to modulate the phenotype under hyperglycemic conditions, which could have a key role in the pathogenesis of diabetic erectile dysfunction.

Cavernous antioxidant effect of green tea, epigallocatechin-3-gallate with/without sildenafil citrate intake in aged diabetic rats

This study aimed to assess the cavernous antioxidant effect of green tea (GT), epigallocatechin-3-gallate (EGCG) with/without sildenafil citrate intake in aged diabetic rats. One hundred and four aged male white albino rat were divided into controls that received ordinary chow, streptozotocin (STZ)-induced aged diabetic rats, STZ-induced diabetic rats on infused green tea, induced diabetic rats on epigallocatechin-3-gallate and STZ-induced diabetic rats on sildenafil citrate added to EGCG. After 8 weeks, dissected cavernous tissues were assessed for gene expression of eNOS, cavernous malondialdehyde (MDA), glutathione peroxidase (GPx), cyclic guanosine monophosphate (cGMP), and serum testosterone (T). STZ-induced diabetic rats on GT demonstrated significant increase in cavernous eNOS, cGMP, GPx and significant decrease in cavernous MDA compared with diabetic rats. Diabetic rats on EGCG demonstrated significant increase in cavernous eNOS, cGMP, GPx and significant decrease in cavernous MDA compared with diabetic rats or diabetic rats on GT. Diabetic rats on EGCG added to sildenafil showed significant increase in cavernous eNOS, cGMP and significant decrease in cavernous MDA compared with other groups. Serum T demonstrated nonsignificant difference between the investigated groups. It is concluded that GT and EGCG have significant cavernous antioxidant effects that are increased if sildenafil is added.

Effects of sildenafil and/or muscle derived stem cells on myocardial infarction

Background

Previous studies have shown that long-term oral daily PDE 5 inhibitors (PDE5i) counteract fibrosis, cell loss, and the resulting dysfunction in tissues of various rat organs and that implantation of skeletal muscle-derived stem cells (MDSC) exerts some of these effects. PDE5i and stem cells in combination were found to be more effective in non-MI cardiac repair than each treatment separately. We have now investigated whether sildenafil at lower doses and MDSC, alone or in combination are effective to attenuate LV remodeling after MI in rats.

Methods

MI was induced in rats by ligature of the left anterior descending coronary artery. Treatment groups were: “Series A”: 1) untreated; 2) oral sildenafil 3 mg/kg/day from day 1; and “Series B”: intracardiac injection at day 7 of: 3) saline; 4) rat MDSC (10⁶ cells); 5) as #4, with sildenafil as in #2. Before surgery, and at 1 and 4 weeks, the left ventricle ejection fraction (LVEF) was measured. LV sections were stained for collagen, myofibroblasts, apoptosis, cardiomyocytes, and iNOS, followed by quantitative image analysis. Western blots estimated angiogenesis and myofibroblast accumulation, as well as potential sildenafil tachyphylaxis by PDE 5 expression. Zymography estimated MMPs 2 and 9 in serum.

Results

As compared to untreated MI rats, sildenafil improved LVEF, reduced collagen, myofibroblasts, and circulating MMPs, and increased cardiac troponin T. MDSC replicated most of these effects and stimulated cardiac angiogenesis. Concurrent MDSC/sildenafil counteracted cardiomyocyte and endothelial cells loss, but did not improve LVEF or angiogenesis, and upregulated PDE 5.

Conclusions

Long-term oral sildenafil, or MDSC given separately, reduce the MI fibrotic scar and improve left ventricular function in this rat model. The failure of the treatment combination may be due to inducing overexpression of PDE5.

Penile Doppler sonographic and clinical characteristics in Peyronie's disease and/or erectile dysfunction: an analysis of 1500 men with male sexual dysfunction

What's known on the subject? and What does the study add? Penile colour Doppler ultrasonography (CDU) can be an invaluable investigative tool to characterize penile abnormalities to complement clinical history and physical examination in the evaluation of men with Peyronie's disease (PD) and/or erectile dysfunction (ED). Although CDU findings between men with PD and those with ED were not markedly different, subtle differences were observed. The classic penile CDU findings in men with PD comprise tunical thickening, intracavernosal fibrosis, septal fibrosis and intracavernosal calcification, while, in men with ED, low peak systolic velocity and high end-diastolic velocity are found on penile haemodynamics. Previously published studies have focused predominantly on either ED or PD exclusively, or examine the risk of progression to ED in the PD population. To our knowledge, this is the largest and most comprehensive analysis of penile CDU and clinical findings in men with PD and/or ED. The large sample size and multivariable analysis allow meaningful interpretation of the results. This study has found some substantial differences in the penile CDU findings of men with PD and/or ED that have not previously been reported. Although the risk factors of ED may be greater than those for PD, there is crossover in age, cardiovascular risk factors, trauma and penile CDU findings in men with PD and/or ED.

OBJECTIVE

To explore the differences in penile colour Doppler ultrasonography (CDU) findings between men with Peyronie's disease (PD) and those with erectile dysfunction (ED).

MATERIALS AND METHODS

Patients presenting with PD and/or ED who underwent penile CDU were recruited to the study. Patient demographics, comorbidities, International Index of Erectile Function-5 scores, previous therapies and physical findings were documented. Penile curvature, presence of tunical thickening, septal fibrosis, intracavernosal fibrosis and calcification, and cavernosal vascular status were recorded.

RESULTS

A total of 1500 men underwent penile CDU during the 10-year period. Of these men, 891 men presented with PD and 609 men had ED only. Men with ED had higher rates of diabetes and coronary artery disease (P < 0.05). Isolated tunical thickening was more common in older men and in the PD cohort. The presence of intracavernosal fibrosis correlated strongly with difficulty maintaining erection (P < 0.05). Impaired cavernosal arterial flow was observed in men with decrease penile rigidity and penile pain, while higher end-diastolic velocities were found in men with difficulty maintaining erection and tunical thickening on penile CDU.

CONCLUSIONS

Men with PD and ED had many similarities and differences on penile CDU. Penile CDU continues to be an invaluable clinical tool in the management of men with male sexual dysfunction.

Reduced expression of myocardin and serum response factor in the cavernous tissue of diabetic rats

This study aimed to investigate the expression of myocardin and serum response factor (SRF) in the cavernous tissue of diabetic rats. The experimental diabetes model was induced in 8-week-old male Sprague-Dawley rats (200-220 g) by a single administration of streptozotocin. Both the diabetes mellitus group (DM group, n = 20) and the control group (NDM group, n = 10) were injected with a low dose of apomorphine to allow for the measurement and comparison of the corresponding penile erections. Western blot and qRT-PCR were used to determine the protein and mRNA expression levels of myocardin and SRF. Erectile function was significantly decreased in the DM group compared with the control group (P < 0.001). The mRNA and protein expression levels of myocardin and SRF were reduced in the cavernous tissue of diabetic rats compared with the control group (P < 0.001). It is concluded that diabetes inhibits the mRNA and protein expression of both myocardin and SRF in the cavernous tissue. This could play a key role in the development of erectile dysfunction in diabetic rats.

PDE5 inhibitors: targeting erectile dysfunction in diabetics

Erectile dysfunction (ED) is strongly linked to cardiovascular disease (CVD), especially in diabetics. ED is associated with deleterious changes in the overall vasculature and is recognized as an indicator of higher risk for adverse cardiovascular events. Endothelial dysfunction, vascular smooth muscle changes and increased fibrosis are indicated as major players in both ED and CVD. ED in diabetics is more refractory to acute treatment with phosphodiesterase-5 (PDE5) inhibitors (Viagra, Cialis, Levitra, Zydena) than in non-diabetics, but recent studies indicate that chronic administration of these drugs improves endothelial function, preserves vascular smooth muscle and decreases fibrotic changes. Use of PDE5 inhibitors in pre-diabetic and diabetic men may protect cardiovascular health, including vascular function in penile tissues.

Reversion of penile fibrosis: Current information and a new horizon

Ageing has a detrimental effect on cavernous tissue and the tunica albuginea of the penis. Furthermore, atherosclerosis of the penile vessels that occurs with ageing causes a decrease in penile oxygen tension. A reduction in smooth muscle cells (SMCs) was shown in relation to diminution of oxygen tension. Chronic ischaemia is therefore not only associated with fibrosis but also with nitric oxide-cyclic guanosine monophosphate reduction. The sensitivity of the α-adrenoceptors on the SMCs increases with ageing. The decrease in penile elasticity and compliance are explained by the changes in the ratio of penile collagen that occur with ageing. Contradictory to the view that testosterone is only necessary for sexual desire, numerous recent studies showed that androgen deprivation produces penile tissue atrophy, alterations in dorsal nerve structure, alterations in endothelial morphology, reduction in trabecular SM content, increase in deposition of extracellular matrix and accumulation of fat-containing cells (adipocytes) in the subtunical region of corpus cavernosum. The aim of the current review is to shed some light on the underlying aetiology of corporal fibrosis especially ageing, cavernous nerve damage, androgen deprivation and tunical fibrosis. Ultimately I will address the proposed prevention of erectile dysfunction associated with penile fibrosis.

Cardiovascular protective effects of nebivolol in Zucker diabetic fatty rats

BACKGROUND

Although effective in reducing blood pressure, therapy with a first-generation [beta]-blocker is currently controversial in metabolic syndrome due to its negative impact on carbohydrate and lipid metabolism.

OBJECTIVE AND DESIGN

We evaluated the effects of nebivolol, a third-generation highly selective [beta]-blocker with additional vasodilating activity, versus the traditional [beta]-blocker atenolol in controlling functional and morphological cardiovascular damage in a rat model of metabolic syndrome.

METHODS

During 6 months, Zucker diabetic fatty (ZDF) rats and control lean Zucker rats (LZR) were studied. The experimental groups were: untreated ZDF, ZDF along with nebivolol, ZDF along with atenolol and LZR. Blood pressure, plasma insulin, triglycerides, cholesterol, glucose and platelet aggregation were evaluated. Malondialdehyde, reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio, CuZn superoxide dismutase, catalase and glutathione peroxidase were determined in heart homogenates and transforming growth factor [beta]1 and plasminogen activator inhibitor-1 (PAI-1) expression, by immunohistochemistry (IHC). Vascular reactivity, vascular cell adhesion molecule-1, platelet endothelial cell adhesion molecule-1, PAI-1, enhanced nitric oxide synthase and collagen expression were evaluated in aorta.

RESULTS

Nebivolol and atenolol presented a similar reduction in blood pressure. However, nebivolol showed a better lipid profile, preserved left ventricular function, a significant control in left ventricular geometry and moderated left ventricular hypertrophy versus atenolol. Significant reduction in platelet aggregation and a substantial endothelium-dependent and endothelium-independent relaxation in vessels were also shown in the nebivolol group versus atenolol group. Antioxidant defenses were preserved by nebivolol with a reduction in oxidative stress parameters. Vascular cell adhesion molecule-1, platelet endothelial cell adhesion molecule-1, PAI-1 and eNOS were favorably modulated with nebivolol in vessel wall. TGF[beta]1, PAI-1 and accumulation of collagen-III and collagen-I were also diminished in heart with nebivolol.

CONCLUSION

The present study provides substantial information supporting an actual protective role of nebivolol in comparison with atenolol in experimental metabolic syndrome.

Acute effect of phosphodiesterase type 5 inhibitor on serum oxidative status and prolidase activities in men with erectile dysfunction

OBJECTIVES

To investigate the acute effect of phosphodiesterase type 5 (PDE5) inhibitor on erectile dysfunction by evaluating serum oxidative status and prolidase activity.

METHODS

Serum samples of 36 patients with erectile dysfunction and 30 control cases were analyzed for total antioxidant status, total oxidant status, and prolidase activity, before and after the administration of tadalafil citrate.

RESULTS

Before and after tadalafil citrate administration, serum total antioxidant status, total oxidant status, and prolidase were 1.1+0.0 vs. 1.6 + 0.0 umol H₂O₂ Eq/L, 10.3+1.1 vs. 6.9 + 1.2 umol H₂O₂ Eq/L, and 236.4+19.5 vs. 228.2 + 19.2 U/L, respectively (p < 0.0001 for all).

CONCLUSIONS

Evaluation of serum oxidative status and prolidase activity confirmed the beneficial acute effects of PDE5 inhibitor in patients with erectile dysfunction.

Antifibrotic effects of pioglitazone on the kidney in a rat model of type 2 diabetes mellitus

BACKGROUND

Recent evidence suggests that treatment of type 2 diabetes with thiazolidinediones [peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists], ameliorates glomerulosclerosis and tubulointerstitial fibrosis in the rat kidney. In the current work, we have investigated whether these drugs, and specifically pioglitazone (PGT), act by preventing fibrosis and kidney dysfunction mainly through antioxidant and anti-inflammatory effects, independently of glycaemic control.

METHODS

Male 2- to 3-month-old obese Zucker fa/fa (OZR) and ZDF fa/fa rats (ZDFR), and their control the lean Zucker rat (LZR), were used. Diabetic rats were given either a low dose (0.6 mg/kg/day) or a high dose (12 mg/ kg/day) of PGT in the chow for 2 or 4-5 months. Glycaemia, blood pressure, creatinine clearance and proteinuria were determined, and the underlying histopathology was defined with markers of fibrosis, glomerular damage, oxidative stress and inflammation by immunohistochemistry/ quantitative image analysis in tissue sections, and western blots and ad hoc assays in fresh tissue.

RESULTS

PGT at low doses given for 4-5 months considerably reduced blood pressure, proteinuria and creatinine clearance. This was associated with amelioration of renal tissue damage and fibrosis, evidenced by the glomerulosclerosis, tubulointerstitial fibrosis, tubular atrophy and podocyte injury indexes, and of oxidative stress and inflammation, as shown by the decrease in the respective markers, although glycaemia remained high and obesity was not affected.

CONCLUSIONS

These results indicate that low doses of PGT ameliorate renal fibrosis and preserve renal function in this animal model of metabolic syndrome, independently of glycaemic control or effects on body weight.