High cholesterol feeding in C57/Blc6 mice alters expression within the VEGF receptor-ligand family in corporal tissue

INTRODUCTION

Angiogenesis, the growth and proliferation of blood vessels from existing vascular structures, is mediated by many cytokine growth factors and receptors, among the most important are the vascular endothelial growth factor (VEGF) family.

AIM

Decreases in VEGF receptor signaling have been linked to abnormalities in vasoreactivity in corporal tissue, but it is unknown if alterations in the VEGF ligands and/or receptors contribute to this process.

MAIN OUTCOME MEASURES

We sought to determine changes in vasoreactivity and the expression of the family of VEGF ligands and receptors in corporal tissue with cholesterol feeding in C57BL6 mice. Methods. Twenty-four mice (N = 8/group) were fed a normal diet (Group 1) or a 1.25% high cholesterol diet for 4 (Group 2) or 12 (Group 3) weeks. Isometric tension studies were performed on corporal strips and dose response curves were generated to evaluate endothelium-dependent and endothelium-independent vasoreactivities. Levels of VEGF-A, B, C, D, VEGF receptors (VEGFRs) were detected by PCR (polymerase chain reaction) and/or western blot/enzyme-linked immunosorbent assay (ELISA). Endothelial and smooth muscle cell contents were determined by immunohistochemistry.

RESULTS

At 4 weeks there was a small but significant decrease in endothelium-dependent vasoreactivity. Both mRNA and protein levels of VEGFR-1 were decreased, while VEGF-B was increased in Group 2 vs. Group 1, with no change in VEGF-A or endothelial cell content. By 12 weeks, decreases in both endothelium-dependent and endothelium-independent vasoreactivity were evident with decrease in most VEGF ligands (except VEGF-B), receptors, and receptor signaling.

CONCLUSIONS

Cholesterol feeding in C57BL6 mice results in alterations in the VEGF receptor-ligand family that may initially serve to limit the degree of vascular injury but these adaptations fail with the continuation of cholesterol feeding.

Revision washout decreases implant capsule tissue culture positivity: a multicenter study

PURPOSE

Positive cultures, visible biofilm and confocal micrography confirm bacterial presence on clinically uninfected inflatable penile prostheses at revision surgery. Salvage irrigation has been proved to rescue patients with clinically infected inflatable penile prostheses. Similar washout at revision for noninfectious reasons significantly lowers subsequent infection rates. We investigated a larger series of patients for positive culture rates and evaluated implant capsule tissue culture rates before and after revision washout.

MATERIALS AND METHODS

At 4 institutions a total of 148 patients with inflatable penile prostheses underwent revision surgery for noninfectious reasons between June 2001 and September 2005. Swab cultures of the fluid around the pump and visible biofilm were obtained. Also, in 65 patients a wedge of tissue from the capsule that forms around the pump was cultured. After implant removal revision washout of the implant spaces was performed and a second wedge of tissue was cultured.

RESULTS

Of the 148 patients 97 (66%) had positive bacterial swab cultures of the fluid around the pump or biofilm. A total of 124 isolates were cultured. Of the 65 implant capsule tissue cultures obtained before washout 28 (43%) were positive for bacteria, while 16 (25%) obtained after revision washout were positive.

CONCLUSIONS

Positive cultures and visible bacterial biofilm are present on clinically uninfected inflatable penile prostheses at revision surgery in most patients. Revision washout appears to decrease the bacterial load on implant capsule tissue at revision surgery of inflatable penile prostheses for noninfectious reasons.

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.

A Mouse Model of Hypercholesterolemia-Induced Erectile Dysfunction

INTRODUCTION

Hypercholesterolemia is one of the most important risk factors for the development of erectile dysfunction (ED) in men.

AIM

We employed an established mouse model of hypercholesterolemia.

MAIN OUTCOME MEASURES

We test for abnormalities in vasoreactivity in corporal tissue and temporally correlated changes in vasoreactivity with alterations in histology and protein expression.

METHODS

A total of 150 mice were studied. A total of 100 apolipoprotein-E knockout (ApoE(-/-)) mice were fed a 1.25% cholesterol diet for 2, 4, 8, and 12 weeks (N = 25/group), while a group of ApoE(-/-) and wild-type Bl-6 mice were fed a normal diet. The study was terminated, and all mice were harvested at 22 weeks of age for vasoreactivity, histology, and protein studies from corporal tissues. Dose-response curves were generated to evaluate endothelium-dependent and endothelium-independent vasoreactivity, ex vivo. The contents of endothelial cells, smooth muscle cells, and smooth muscle/collagen ratio were assessed by immunohistochemistry staining or Masson staining. Level of cyclic guanosine monophosphate (cGMP) was detected by enzyme immunoassay assay. Levels of phosphorylated endothelial nitric oxide synthase (p-eNOS)/total eNOS, neuronal nitric oxide synthase (nNOS), and cyclic GMP-dependent kinase (cGK-1) protein were assessed by Western analysis.

RESULTS

Abnormalities in endothelium-dependent and endothelium-independent vasoreactivities, endothelial content, smooth muscle/collagen ratio, p-eNOS phosphorylation at Ser1177 only, nNOS, cGMP, and cGK-1 changed with the different durations of the high-cholesterol diet.

CONCLUSIONS

These data demonstrate that this mouse model is suitable for investigating aspects of hypercholesterolemic ED.

Recovery of sexual function after prostate cancer treatment

PURPOSE OF REVIEW

The estimated disease-free survival rates are approximately equivalent across standard treatments for localized prostate cancer. We aim to review the efforts being made to reduce posttreatment erectile dysfunction, a major morbidity of these therapies.

RECENT FINDINGS

Potency as an important factor in a patient's decision about choosing a form of therapy has been demonstrated in the literature. For nerve-sparing surgery, though some proponents of laparoscopic radical prostatectomy believe it may confer an advantage over the open surgical techniques, the published data is scarce and has yet to demonstrate a true difference. Enthusiasm has declined for sural nerve grafting because of the associated complexity of the procedure and inconsistent results. Concurrent implantation of a penile prosthesis is an option for certain patients who already have some baseline erectile dysfunction or are not candidates for nerve-sparing surgery. Agents such as phosphodiesterase inhibitors, immunophilin ligands, and recombinant human erythropoietin have demonstrated potential benefits in early reports of both in-vitro and ongoing clinical trials.

SUMMARY

Currently, no standard treatment or prophylaxis exists for posttreatment erectile dysfunction. Neuro-protective and regenerative therapies, including the immunophilin ligands, hold promise to reduce the morbidity of localized prostate cancer therapy.

Use of negative-pressure dressings and split-thickness skin grafts following penile shaft reduction and reduction scrotoplasty in the management of penoscrotal elephantiasis

From 1988 to 2005, 8 men who presented with penoscrotal elephantiasis underwent penile shaft degloving and reduction scrotoplasty, followed by transplantation of a split-thickness skin graft (STSG) to the penile shaft. The etiology of elephantiasis in these patients included self-injection of viscous fluid and postsurgical obstructive lymphedema. In the 6 most recent cases, negative-pressure dressings were applied over the STSG to promote graft take, and STSG take rate was 100%. The results of our series corroborate those of a previous report, which showed circumferential negative-pressure dressings to be safe and efficacious in bolstering STSGs to the penile shaft. Furthermore, these results suggest that the use of negative-pressure dressings may improve graft take in this patient population.

Biofilm formation on clinically noninfected penile prostheses

PURPOSE

Biofilms are matrix enclosed bacterial populations that adhere to each other and/or to surfaces of implanted medical devices. Biofilm formation has consistently been demonstrated in association with infected penile prosthetic material. Clinically noninfected patients undergoing revision for mechanical malfunction have a surprisingly high rate of positive intraoperative cultures. After revision replacement prostheses have a higher rate of postoperative infection than first time implants. We characterized biofilm formation on penile prostheses in clinically noninfected patients undergoing revision surgery.

MATERIALS AND METHODS

Ten patients undergoing revision or removal of inflatable penile prosthetic devices due to mechanical malfunction were included. Specimens from the corporeal cylinders, scrotal pump and reservoir were analyzed. Bacterial biofilm coverage was detected and characterized using confocal scanning laser microscopy.

RESULTS

Bacterial biofilm formation associated with multiple microorganisms was demonstrated on 8 of 10 prostheses. Biofilms consisted of gram-positive rods, cocci and fungal elements.

CONCLUSIONS

The degree of biofilm formation on these prosthetic devices suggests that most patients have bacterial coverage on the implant. Host mechanisms to control infection may lead to a homeostatic balance that enables biofilms to exist on the surface of the prosthesis without generating clinical infection. A critical threshold of biofilm extent may exist beyond which clinical infection may occur. These results justify further evaluation of biofilms and penile prosthesis infections. Furthermore, the findings help to explain why strategies such as mini salvage procedures to eliminate subclinical biofilms may decrease the postoperative infection risk in patients undergoing repair or replacement of penile prostheses.

Etiology of ejaculation and pathophysiology of premature ejaculation

INTRODUCTION

Ejaculation is comprised of three stages of the male sexual response cycle, namely emission, ejection, and orgasm; however, in comparison with erection, which is a well-understood component of male sexual response, the pathophysiology of ejaculation has yet to be fully delineated. Premature ejaculation (PE), the most common sexual disorder in men, while believed to have a multifactorial etiology, is even less well understood.

AIM

This article reviews the physiology of ejaculation, and the multifactorial pathophysiology of PE.

METHODS

The Sexual Medicine Society of North America hosted a State of the Art Conference on Premature Ejaculation on June 24-26, 2005 in collaboration with the University of South Florida. The purpose was to have an open exchange of contemporary research and clinical information on PE. There were 16 invited presenters and discussants; the group focused on several educational objectives.

MAIN OUTCOME MEASURE

Data were obtained by extensive examination of published peer-reviewed literature.

RESULTS

Evidence supports that biologic mechanisms associated with neurotransmitters such as norepinephrine, serotonin, oxytocin, Gamma-amino-butyric acid, and nitric oxide (NO) as well as the hormone estrogen play central roles in ejaculation, and subsequently may mediate PE. There is also emerging evidence to show that hyperthyroidism may be a causal factor in PE. Recent data also suggest that psychogenic factors include high level of any experience by some men with PE.

CONCLUSIONS

The pathophysiology of both lifelong and acquired PE appears to be both neurobiogenic and psychogenic. While psychogenic factors appear to be contributory to PE, pharmacologic intervention of PE can modify intravaginal ejaculatory latency time (IELT), which suggests that IELT is a biological variable, and is likely biologically dependent upon neurotransmitters and hormones.

Timing and patterns of recurrences and deaths from prostate cancer following adjuvant pelvic radiotherapy for pathologic stage T3/4 adenocarcinoma of the prostate

To determine the timing and patterns of late recurrence after radical prostatectomy (RP) alone or RP plus adjuvant radiotherapy (RT). Between 1970 and 1983, 159 patients underwent RP for newly diagnosed adenocarcinoma of the prostate and were found to have positive surgical margins, extracapsular extension and/or seminal vesicle invasion. Of these, 46 received adjuvant RT and 113 did not. The RT group generally received 45-50 Gy to the whole pelvis, then a boost to the prostate bed (total dose of 55-65 Gy). In the RP group, 62% received neoadjuvant/adjuvant androgen deprivation vs 17% in the RT group. Patients were analyzed with respect to timing and patterns of failure. Only one patient was lost to follow-up. The median follow-up for surviving patients was nearly 20 years. The median time to failure in the surgery group was 7.5 vs 14.7 years in the RT group (P=0.1). Late recurrences were less common in the surgery group than the RT group (9 and 1% at 10 and 15 years, respectively vs 17 and 9%). In contrast to recurrences, nearly half of deaths from prostate cancer occurred more than 10 years after treatment. Deaths from prostate cancer represented 55% of all deaths in these patients. Recurrences beyond 10 years after RP in this group of patients were relatively uncommon. Despite its long natural history, death from prostate cancer was the most common cause of mortality in this population with locally advanced tumors, reflecting the need for more effective therapy.

Efficacy of Tadalafil in Men with Erectile Dysfunction Naïve to Phosphodiesterase 5 Inhibitor Therapy Compared with Prior Responders to Sildenafil Citrate

INTRODUCTION

Tadalafil, an inhibitor of phosphodiesterase 5 (PDE5), is indicated for treatment of erectile dysfunction. Most tadalafil clinical trials excluded patients with unsuccessful prior treatment with sildenafil citrate (sildenafil).

AIM

This retrospective analysis of pooled data from 14 tadalafil clinical trials examines the effect of this exclusion by comparing efficacy results in 1,349 patients without prior sildenafil use (naïve, presumably a mixture of potential responders and nonresponders) with efficacy results in 1,440 patients previously responsive to sildenafil (prior responders).

MAIN OUTCOME MEASURES

Efficacy measures included the International Index of Erectile Function (IIEF) erectile function (EF) domain, overall satisfaction (OS), and intercourse satisfaction (IS) domain scores; Sexual Encounter Profile (SEP) diary questions 2 through 5 (SEP2 [successful penetration], SEP3 [successful intercourse], SEP4 (satisfaction with hardness of erection), and SEP5 [overall satisfaction with the sexual experience]); and a Global Assessment Question (GAQ1) (13/14 trials) about erection improvement. Efficacy was compared using analysis of covariance (IIEF and SEP) and logistic regression (GAQ1) models.

METHODS

After a 4-week, treatment-free, run-in period, patients in 14 double-blind, placebo-controlled, parallel-group trials were treated with tadalafil 10 mg, tadalafil 20 mg, or placebo for 12 weeks (dosed as needed before sexual activity, no more than once daily).

RESULTS

Tadalafil improved erectile function compared with placebo (P < 0.001) in naïve patients and sildenafil prior responders for all efficacy measures. For most efficacy outcomes, responses in the naïve group (probable mix of responders and nonresponders) were not statistically different from responses in the prior-responder group (P >or= 0.10).

CONCLUSIONS

The similar responses of these two patient groups observed in this post hoc analysis suggest, but do not confirm, that exclusion of sildenafil nonresponders in previously reported tadalafil clinical trials may not have substantially affected efficacy outcomes. Tadalafil improved erectile function in patients naïve to PDE5 inhibitor therapy and in patients who previously responded to sildenafil therapy.

ORIGINAL RESEARCH—BASIC SCIENCE: Intracavernosal Basic Fibroblast Growth Factor Improves Vasoreactivity in the Hypercholesterolemic Rabbit

PURPOSE

We determined the effects of intracavernosal injection (ICI) of recombinant basic fibroblast growth factor (rbFGF) on corporal tissue in hypercholesterolemic rabbits.

METHODS

Twenty New Zealand White rabbits were fed a 1% cholesterol diet for 6 weeks and were randomly divided into four groups. Group 1 (N = 5) received an ICI of phosphate buffered saline solution (PBS) once and again 3 weeks later. Group 2 (N = 4) received an ICI of 2.5 microg rbFGF once and PBS 3 weeks later. Group 3 (N = 6) received an ICI of 2.5 microg rbFGF once and again 3 weeks later. Group 4 (N = 5) received an ICI of 2.5 microg rbFGF once. All animals were maintained on the high cholesterol diet until sacrifice, 3 weeks after last injection. Strips of corporal tissue were submaximally contracted with norepinephrine, and dose-response curves were generated to evaluate endothelial-dependent (acetylcholine, ACH) and endothelial-independent (sodium nitroprusside, SNP) vasoreactivity. Protein levels of bFGF and vascular endothelial growth factor (VEGF) were assessed by enzyme-linked immunosorbent assay. Neuronal nitric oxide synthase (nNOS) protein and mRNA were detected by Western blot and semi-quantitative polymerase chain reaction, respectively.

RESULTS

Vasoreactivity was improved by bFGF treatment as shown by higher ED50[-log(M)] of ACH and SNP in Groups 2, 3, and 4. The expression of bFGF protein, VEGF protein, nNOS protein, and mRNA were all increased after bFGF treatment.

CONCLUSIONS

ICI of bFGF improved vasoreactivity in hypercholesterolemic rabbit corporal tissue, offering a new direction to explore for the treatment of erectile dysfunction.

Cholesterol Feeding Reduces Vascular Endothelial Growth Factor Signaling in Rabbit Corporal Tissues

PURPOSE

Hypercholesterolemia is a major risk factor for erectile dysfunction (ED), but the mechanisms are not completely understood. Vascular endothelial growth factor (VEGF) is reduced in rabbit corporal tissue with cholesterol feeding. VEGF signaling leads to the phosphorylation of Akt and endothelial nitric oxide synthase (p-Akt and p-eNOS).

MATERIAL AND METHODS

New Zealand White rabbits (n = 50) were fed a 1% cholesterol (n = 8, 8, 8, 4) or normal (n = 6, 6, 6, 4) diet for 2, 4.5, 7.5, and 12 weeks. Akt, p-Akt, and p-Akt/Akt were measured by enzyme-linked immunosorbent assay. Levels of eNOS, p-eNOS, and neuronal and inducible nitric oxide synthase (nNOS and iNOS) mRNA and protein were assessed by polymerase chain reaction and Western analysis.

RESULTS

Cholesterol feeding was associated with a significant decrease in p-Akt/Akt 2.16-fold (P < 0.05), 3.28-fold (P < 0.02), and 3.42-fold (P < 0.02) at 4.5, 7.5, and 12 weeks, respectively. The reduction in p-Akt/Akt with the cholesterol diet at 2 weeks was not significantly different, but the correlation between the duration of cholesterol feeding and the reduction in p-Akt/Akt was high (r( 2) = 0.858). eNOS protein or mRNA did not change with cholesterol feeding, but p-eNOS was significantly decreased at 4.5 weeks and all subsequent time points. nNOS mRNA and protein levels were decreased at 4.5 weeks and all subsequent time points, while iNOS was not different between groups.

CONCLUSIONS

Hypercholesterolemia results in decreased VEGF signaling and decreased levels of the active form of eNOS in corporal tissue. Levels of nNOS were reduced by a different mechanism. VEGF signaling may provide a target to modulate ED.

The Prepuce as a Donor Site for Reconstruction of an Extravasation Injury to the Foot in a Newborn

Extravasation injury is a common event in pediatric intensive-care units. This is the first report of successful utilization of the prepuce as a skin graft to reconstruct a full thickness skin necrosis due to a phenobarbital extravasation to the forefoot of a newborn.

DECREASES IN CORPOREAL VASCULAR ENDOTHELIAL GROWTH FACTOR EXPRESSION PRECEDE VASOREACTIVITY CHANGES IN CHOLESTEROL FED RABBITS

PURPOSE

We determined temporal changes in vasoreactivity and angiogenic growth factor levels in corporeal tissue at varying time points after the induction of hypercholesterolemia in rabbits.

MATERIALS AND METHODS

A total of 42 New Zealand White rabbits were fed a 1% cholesterol (8 per group) or normal (6 per group) diet for 2, 4.5 or 7.5 weeks. Vascular endothelial growth factor (VEGF) mRNA expression in corpus cavernosum was assessed by real-time polymerase chain reaction analyses for the 3 isoforms VEGF121, VEGF165 and VEGF189. Isometric tension studies were performed and dose response curves were generated to evaluate endothelial dependent and endothelial independent vasoreactivity.

RESULTS

Real-time polymerase chain reaction analysis showed 2.2 to 2.5 and 1.5 to 2.7-fold decreases in VEGF121 and VEGF165, respectively, in the corporeal tissues of the high cholesterol group vs the normal diet group at the 2 week time point. At 2 weeks VEGF189 was unchanged but it was decreased 1.5 to 2-fold at 4.5 weeks. Acetylcholine isometric tension studies revealed no difference in mean ED50 (-log [M]) +/- SD until 7.5 weeks of high cholesterol diet (5.10 +/- 0.64 vs 3.95 +/- 1.35, p = 0.0269). The response to sodium nitroprusside was not statistically different at any time point. Endothelial cell and smooth muscle content were decreased for the high cholesterol vs normal diet at 4.5 weeks (endothelial only) and 7.5 weeks (each cell).

CONCLUSIONS

Alterations in corporeal tissue levels of VEGF occur before abnormalities in vasoreactivity. The results suggest that VEGF has a role in normal vasoreactivity in corporeal tissue and, thereby, in normal erectile function.