Injections of adipose tissue-derived stem cells and stem cell lysate improve recovery of erectile function in a rat model of cavernous nerve injury

INTRODUCTION

Erectile dysfunction (ED) remains a major complication after radical prostatectomy. The use of adipose tissue-derived stem cells (ADSCs) has shown promising results for the treatment of ED. However, the mechanisms of action for stem cell therapy remain controversial, with increasing evidence pointing to paracrine pathways.

AIM

To determine the effects and to identify the mechanism of action of ADSC and ADSC-derived lysate in a rat model of cavernous nerve (CN) crush injury.

METHODS

Thirty-two male Sprague-Dawley rats were randomly divided into four equal groups: one group underwent sham operation, while three groups underwent bilateral CN crush. Crush-injury groups were treated at the time of injury with intracavernous injection of ADSC, lysate, or vehicle only (injured controls). Erectile function was assessed by CN electrostimulation at 4 weeks. Penile tissue was collected for histology.

MAIN OUTCOME MEASURES

  Intracavernous pressure increase upon CN stimulation; neuronal nitric oxide synthase (nNOS) content in the dorsal penile nerve; smooth muscle content, collagen content, and number of apoptotic cells in the corpus cavernosum.

RESULTS

Both ADSC and lysate treatments resulted in significant recovery of erectile function, as compared with vehicle treatment. nNOS content was preserved in both the ADSC and lysate group, with significantly higher expression compared with vehicle-treated animals. There was significantly less fibrosis and a significant preservation of smooth muscle content in the ADSC and lysate groups compared with injured controls. The observed functional improvement after lysate injection supports the hypothesis that ADSCs act through release of intracellular preformed substances or by active secretion of certain biomolecules. The underlying mechanism of recovery appears to involve neuron preservation and cytoprotection by inhibition of apoptosis.

CONCLUSIONS

Penile injection of both ADSC and ADSC-derived lysate can improve recovery of erectile function in a rat model of neurogenic ED.

Treatment of stress urinary incontinence with adipose tissue-derived stem cells

BACKGROUND AIMS

Effective treatment for stress urinary incontinence (SUI) is lacking. This study investigated whether transplantation of adipose tissue-derived stem cells (ADSC) can treat SUI in a rat model.

METHODS

Rats were induced to develop SUI by postpartum vaginal balloon dilation and bilateral ovariectomy. ADSC were isolated from the peri-ovary fat, examined for stem cell properties, and labeled with thymidine analog BrdU or EdU. Ten rats received urethral injection of saline as a control. Twelve rats received urethral injection of EdU-labeled ADSC and six rats received intravenous injection of BrdU-labeled ADSC through the tail vein. Four weeks later, urinary voiding function was assessed by conscious cystometry. The rats were then killed and their urethras harvested for tracking of ADSC and quantification of elastin, collagen and smooth muscle contents.

RESULTS

Cystometric analysis showed that eight out 10 rats in the control group had abnormal voiding, whereas four of 12 (33.3%) and two of six (33.3%) rats in the urethra-ADSC and tail vein-ADSC groups, respectively, had abnormal voiding. Histologic analysis showed that the ADSC-treated groups had significantly higher elastin content than the control group and, within the ADSC-treated groups, rats with normal voiding pattern also had significantly higher elastin content than rats with voiding dysfunction. ADSC-treated normal-voiding rats had significantly higher smooth muscle content than control or ADSC-treated rats with voiding dysfunction.

CONCLUSIONS

Transplantation of ADSC via urethral or intravenous injection is effective in the treatment and/or prevention of SUI in a pre-clinical setting.

Recruitment of intracavernously injected adipose-derived stem cells to the major pelvic ganglion improves erectile function in a rat model of cavernous nerve injury

BACKGROUND

Intracavernous (IC) injection of stem cells has been shown to ameliorate cavernous-nerve (CN) injury-induced erectile dysfunction (ED). However, the mechanisms of action of adipose-derived stem cells (ADSC) remain unclear.

OBJECTIVES

To investigate the mechanism of action and fate of IC injected ADSC in a rat model of CN crush injury.

DESIGN, SETTING, AND PARTICIPANTS

Sprague-Dawley rats (n=110) were randomly divided into five groups. Thirty-five rats underwent sham surgery and IC injection of ADSC (n=25) or vehicle (n=10). Another 75 rats underwent bilateral CN crush injury and were treated with vehicle or ADSC injected either IC or in the dorsal penile perineural space. At 1, 3, 7 (n=5), and 28 d (n=10) postsurgery, penile tissues and major pelvic ganglia (MPG) were harvested for histology. ADSC were labeled with 5-ethynyl-2-deoxyuridine (EdU) before treatment. Rats in the 28-d groups were examined for erectile function prior to tissue harvest.

MEASUREMENTS

IC pressure recording on CN electrostimulation, immunohistochemistry of the penis and the MPG, and number of EdU-positive (EdU+) cells in the injection site and the MPG.

RESULTS AND LIMITATIONS

IC, but not perineural, injection of ADSC resulted in significantly improved erectile function. Significantly more EdU+ ADSC appeared in the MPG of animals with CN injury and IC injection of ADSC compared with those injected perineurally and those in the sham group. One day after crush injury, stromal cell-derived factor-1 (SDF-1) was upregulated in the MPG, providing an incentive for ADSC recruitment toward the MPG. Neuroregeneration was observed in the group that underwent IC injection of ADSC, and IC ADSC treatment had beneficial effects on the smooth muscle/collagen ratio in the corpus cavernosum.

CONCLUSIONS

CN injury upregulates SDF-1 expression in the MPG and thereby attracts intracavernously injected ADSC. At the MPG, ADSC exert neuroregenerative effects on the cell bodies of injured nerves, resulting in enhanced erectile response.

Treatment of erectile dysfunction in the obese type 2 diabetic ZDF rat with adipose tissue-derived stem cells

INTRODUCTION

Erectile dysfunction (ED) is a major complication of type 2 diabetes, and many diabetic men with ED are refractory to common ED therapies.

AIM

To determine whether autologous adipose tissue-derived stem cells (ADSCs) injected into the penis of impotent type 2 diabetic rats improve erectile function.

MAIN OUTCOME MEASURES

Blood glucose levels, intracavernous pressure (ICP) increase upon cavernous nerve (CN) electrostimulation, and immunohistochemistry.

METHODS

Twenty-two male Zucker diabetic fatty (ZDF) rats were used. At 22 weeks of age, all the animals underwent unilateral CN electrostimulation and ICP measurement to confirm impotence. Paragonadal adipose tissue was harvested to procure ADSCs. The impotent animals were randomized to ADSC treatment and sham control groups. At 23 weeks of age, the treatment group animals underwent a penile injection of 1 million ADSCs; the control group animals received vehicle only. Erectile function studies were repeated at 26 weeks of age, followed by tissue harvest.

RESULTS

The rats developed diabetes within the first 10 weeks of age. At 22 weeks of age, 20 out of the 22 rats presented with ED. The post-treatment ICP increase during CN stimulation and ICP increase/mean arterial pressure were significantly higher in the treatment group compared with controls. Three weeks after injection into the corpus cavernosum, only a small number of BrdU-labeled ADSCs was detectable within corporal tissue of the treatment group. There was a significant increase in neuronal nitric oxide synthase (nNOS) in the penile dorsal nerve and in the number of endothelial cells in the corpora cavernosa of the rats in the treatment group.

CONCLUSION

Autologous ADSCs injected into the penis were effective to improve erectile function and to alter the microarchitecture of the corpus cavernosum. Since the number of ADSCs retained in the corpus cavernosum is very small, we postulate that their paracrine function, not trans-differentiation to smooth muscle or endothelial cells, is responsible for the improvement in penile function.

Erectogenic and neurotrophic effects of icariin, a purified extract of horny goat weed (Epimedium spp.) in vitro and in vivo

INTRODUCTION

Epimedium species (aka horny goat weed) have been utilized for the treatment of erectile dysfunction in Traditional Chinese Medicine for many years. Icariin (ICA) is the active moiety of Epimedium species.

AIM

To evaluate the penile hemodynamic and tissue effects of ICA in cavernous nerve injured rats. We also studied the in vitro effects of ICA on cultured pelvic ganglia.

METHODS

Rats were subjected to cavernous nerve injury and subsequently treated for 4 weeks with daily gavage feedings of a placebo solution of normal saline and Dimethyl sulfoxide (DMSO) vs. ICA dissolved in DMSO at doses of 1, 5, and 10 mg/kg. A separate group underwent a single dose of ICA 10 mg/kg 2 hours prior to functional testing. Functional testing with cavernous nerve stimulation and real-time assessment of intracavernous pressure (ICP) was performed at 4 weeks. After functional testing, penile tissue was procured for immunohistochemistry and molecular studies. In separate experiments, pelvic ganglia were excised from healthy rats and cultured in the presence of ICA, sildenafil, or placebo culture media.

MAIN OUTCOME MEASURE

Ratio of ICP and area under the curve (AUC) to mean arterial pressure (MAP) during cavernous nerve stimulation of subject rodents. We also assayed tissue expression of neuronal nitric oxide synthase (nNOS), eNOS: endothelial nitric oxide synthase (eNOS), calponin, and apoptosis via immunohistochemistry and Western blot. Serum testosterone and luteinizing hormone (LH) were assayed using enzyme-linked immunosorbant assay (ELISA). Differential length of neurite outgrowth was assessed in cultured pelvic ganglia.

RESULTS

Rats treated with low-dose ICA demonstrated significantly higher ICP/MAP and AUC/MAP ratios compared with control and single-dose ICA animals. Immunohistochemistry and Western blot were revealing of significantly greater positivity for nNOS and calponin in penile tissues of all rats treated with ICA. ICA led to significantly greater neurite length in cultured specimens of pelvic ganglia.

CONCLUSION

ICA may have neurotrophic effects in addition to known phosphodiesterase type 5 inhibiting effects.

Transplanted Human Stem Cell-Derived Interneuron Precursors Mitigate Mouse Bladder Dysfunction and Central Neuropathic Pain after Spinal Cord Injury

Neuropathic pain and bladder dysfunction represent significant quality-of-life issues for many spinal cord injury patients. Loss of GABAergic tone in the injured spinal cord may contribute to the emergence of these symptoms. Previous studies have shown that transplantation of rodent inhibitory interneuron precursors from the medial ganglionic eminence (MGE) enhances GABAergic signaling in the brain and spinal cord. Here we look at whether transplanted MGE-like cells derived from human embryonic stem cells (hESC-MGEs) can mitigate the pathological effects of spinal cord injury. We find that 6 months after transplantation into injured mouse spinal cords, hESC-MGEs differentiate into GABAergic neuron subtypes and receive synaptic inputs, suggesting functional integration into host spinal cord. Moreover, the transplanted animals show improved bladder function and mitigation of pain-related symptoms. Our results therefore suggest that this approach may be a valuable strategy for ameliorating the adverse effects of spinal cord injury.

The effect of intracavernous injection of adipose tissue-derived stem cells on hyperlipidemia-associated erectile dysfunction in a rat model

INTRODUCTION

Hyperlipidemia has been associated with erectile dysfunction (ED) via damage to the cavernous endothelium and nerves. Adipose tissue-derived stem cells (ADSC) have been shown to differentiate into endothelial cells and secrete vasculotrophic and neurotrophic factors.

AIM

To assess whether ADSC have therapeutic effects on hyperlipidemia-associated ED.

METHODS

Twenty-eight male rats were induced to develop hyperlipidemia with a high-fat diet (hyperlipidemic rats, HR). Ten additional male rats were fed a normal diet to serve as controls (normal rats, NR). Five months later, all rats were subjected to ADSC isolation from paragonadal fat. The cells were cultured for 1 week, labeled with 5-ethynyl-2'-deoxyuridine (EdU), and then injected autologously into the corpus cavernosum of 18 HR. The remaining 10 HR rats were injected with phosphate buffered saline (PBS). At 2 and 14 days post-transplantation, four rats in the HR + ADSC group were sacrificed for tracking of the transplanted cells. At 28 days post-transplantation, all remaining rats were analyzed for serum biochemistry, erectile function, and penile histology.

MAIN OUTCOME MEASURES

Erectile function was assessed by intracavernous pressure (ICP) measurement during electrostimulation of the cavernous nerve. Cavernous nerves, endothelium, and smooth muscle were assessed by immunohistochemistry.

RESULTS

Serum total cholesterol and low-density lipoprotein levels were significantly higher in HR than in NR. High-density lipoprotein level was significantly lower in HR than in NR. Mean ICP/mean arterial pressure ratio was significantly lower in HR + PBS than in NR + PBS or HR + ADSC. Neuronal nitric oxide synthase (nNOS)-positive nerve fibers and endothelial cells were fewer in HR + PBS than in HR + ADSC. Smooth muscle content was significantly higher in both HR groups than in NR.

CONCLUSIONS

Hyperlipidemia is associated with abnormalities in both the nerves and endothelium. Treatment with ADSC ameliorates these adverse effects and holds promise as a potential new therapy for ED.

Functional, metabolic, and morphologic characteristics of a novel rat model of type 2 diabetes-associated erectile dysfunction

OBJECTIVES

To conduct a pilot study to investigate functional, metabolic, and penile morphologic changes in a novel model of lean DM2. Erectile dysfunction (ED) is a frequent sequela in patients with type 2 diabetes mellitus (DM2).

METHODS

Eight rats received a high-fat diet and 2 weeks later, 2 intraperitoneal injections of streptozotocin (STZ, 30 mg/kg). Five age-matched rats served as controls. Insulin challenge tests were performed at 6 and 12 weeks after induction of DM2. At 12 weeks, erectile function was tested by measurement of intracavernous pressure (ICP) increase upon cavernous nerve stimulation. Penile tissue and serum samples were harvested for histology and biochemistry, respectively.

RESULTS

A lean DM2 model was established as demonstrated by decreased insulin resistance, elevated nonfasting plasma glucose levels, hyperlipidemia, and decreased insulin concentration in the absence of obesity. ICP/mean arterial pressure was significantly decreased in DM2 animals (0.29) compared with controls (0.81). Expression of neuronal nitric oxide synthase and rat endothelial cell antigen-1, and the smooth muscle/collagen ratio were significantly decreased in the penis of DM2 animals.

CONCLUSIONS

We propose an inexpensive nongenetic animal model of lean DM2-associated ED. Microanatomical changes in the erectile tissue that reflect an advanced stage of the disease were observed.

Effects of intravenous injection of adipose-derived stem cells in a rat model of radiation therapy-induced erectile dysfunction

INTRODUCTION

Radiation therapy (RT) for prostate cancer is frequently associated with posttreatment erectile dysfunction (ED).

AIM

To investigate whether injection of adipose-derived stem cells (ADSCs) can ameliorate RT-associated ED.

METHODS

Thirty male rats were divided into three groups. The control + phosphate-buffered saline (PBS) group received tail-vein injection of PBS. The radiation + PBS group received radiation over the prostate and tail-vein injection of PBS. The radiation + ADSC group received radiation over the prostate and tail-vein injection of ADSCs, which were labeled with 5-ethynyl-2-deoxyuridine (EdU). Seventeen weeks later, erectile function was evaluated by intracavernous pressure (ICP) in response to electrostimulation of cavernous nerves (CNs). Penile tissue and major pelvic ganglia (MPG) were examined by immunofluorescence (IF) and EdU staining.

MAIN OUTCOME MEASURES

Erectile function was measured by ICP. Protein expression was examined by IF, followed by image analysis and quantification.

RESULTS

Radiation over the prostate caused a significant decrease in erectile function and in the expression of neuronal nitric oxide synthase (nNOS) in penis and MPG. Cavernous smooth muscle (CSM) but not endothelial content was also reduced. Injection of ADSCs significantly restored erectile function, nNOS expression, and CSM content in the irradiated rats. EdU-positive cells were visible in MPG.

CONCLUSIONS

Radiation appears to cause ED via CN injury. ADSC injection can restore erectile function via CN regeneration.

Pentoxifylline promotes recovery of erectile function in a rat model of postprostatectomy erectile dysfunction

BACKGROUND

Cavernous nerve (CN) injury during radical prostatectomy (RP) causes CN degeneration and secondary penile fibrosis and smooth muscle cell (SMC) apoptosis. Pentoxifylline (PTX) is a phosphodiesterase inhibitor that further inhibits multiple cytokine pathways involved in nerve degeneration, apoptosis, and fibrosis.

OBJECTIVES

To evaluate whether PTX enhances erectile function in a rat model of CN injury. DESIGN, SETTING AND INTERVENTIONS: Forty male Sprague-Dawley rats underwent CN crush injury and were randomized to oral gavage feeding of phosphate-buffered saline (vehicle) or PTX 25, PTX 50, or PTX 100 mg/kg per day. Ten animals underwent sham surgery and received vehicle treatment. Treatment continued for 28 d, followed by a wash-out period of 72 h. An additional eight rats underwent resection of the major pelvic ganglion (MPG) for tissue culture and examination of direct effects of PTX on neurite sprouting.

MEASUREMENTS

Intracavernous pressure recording on CN electrostimulation, immunohistologic examination of the penis and the CN distal to the injury site, and length of neurite sprouts in MPG culture.

RESULTS

Daily oral gavage feeding of PTX resulted in significant improvement of erectile function compared to vehicle treatment in all treated groups. After treatment with PTX 50 and PTX 100 mg/kg per day, the expression of neuronal nitric oxide synthase in the dorsal penile nerve was significantly higher than in vehicle-treated rats. Furthermore, PTX treatment prevented collagen deposition and SMC loss in the corpus cavernosum. In the CN, signs of Wallerian degeneration were ameliorated by PTX treatment. MPG culture in medium containing PTX resulted in a significant increase of neurite length.

CONCLUSIONS

PTX treatment following CN injury in rats improved erectile recovery, enhanced nerve regeneration, and preserved the corpus cavernosum microarchitecture. The clinical availability of this compound merits application in penile rehabilitation studies following RP in the near future.

Neurotrophic effects of brain-derived neurotrophic factor and vascular endothelial growth factor in major pelvic ganglia of young and aged rats

OBJECTIVE

To investigate the neurotrophic effect of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) in cultured major pelvic ganglia (MPG) derived from young and aged rats.

MATERIALS AND METHODS

The dorsocaudal region of the MPG was isolated from 12 6-month-old male rats and 12 24-month-old male rats. The MPGs were treated with BDNF, VEGF, or both, at 0, 12.5, 25, 50, 100 and 150 ng/mL to determine the effective concentration for 50% activity (EC(50)) and optimum dosage for promoting neurite growth. Neurite outgrowth from treated MPGs was measured by microscopy. NADPH diaphorase and tyrosine hydroxylase (TH) staining was used to characterize neurites.

RESULTS

Both BDNF and VEGF promoted neurite sprouting from MPG. Neurite growth was more robust in MPGs derived from young rats (6 months) than from aged rats (24 months). The EC(50) for BDNF, VEGF and combined treatment were 10.6, 11.9 and 52 ng/mL in young rats, and 11.3, 12 and 0.75 ng/mL in old rats, respectively. The optimum dosage of both factors for promoting MPG neurite growth in all groups was 25-50 ng/mL. VEGF appeared to favour NADPH diaphorase-positive neurites, whereas BDNF favoured TH-positive neurites.

CONCLUSION

BDNF and VEGF promote neurite growth from cultured MPG; combined treatment produced the most robust neurite outgrowth. Neurite growth from MPGs derived from aged rats was not as robust as it was from MPGs from younger rats. Further studies on the effect of neurotrophins after cavernous nerve injury are warranted.

Intracavernous growth differentiation factor-5 therapy enhances the recovery of erectile function in a rat model of cavernous nerve injury

INTRODUCTION

Neurogenic erectile dysfunction remains a serious complication in the postprostatectomy population. Effective protective and regenerative neuromodulatory strategies are needed.

AIM

To determine the effect of growth differentiation factor-5 (GDF-5) on erectile function and its mechanism in a rat model of cavernous nerve (CN) injury.

MAIN OUTCOME MEASURES

Erectile function was assessed by CN electrostimulation at 4 weeks. Penile tissues were examined by real-time polymerase chain reaction (PCR) and immunohistochemical analyses.

METHODS

Forty-eight male Sprague-Dawley rats were randomly divided into six equal groups: one group underwent sham operation (uninjured controls), while five groups underwent bilateral CN crush. Crush-injury groups were treated at the time of injury with intracavernous injection of a slow-release suspension of liquid microparticles containing no GDF-5 (vehicle), 0.4 microg (low concentration), 2 microg (intermediate concentration), or 10 microg GDF-5 (high concentration). One untreated group served as injured controls.

RESULTS

GDF-5 enhanced erectile recovery and significantly increased intracavernous pressure in the low and intermediate-concentration groups vs. injured controls. Low-concentration GDF-5 demonstrated the best functional preservation, as the intracavernous pressure increase in this group did not differ significantly from uninjured controls. A dose-response relationship was confirmed for the effects of GDF-5 in penile tissue. Low-concentration GDF-5 showed better preservation of the penile dorsal nerves and antiapoptotic effects in the corpus cavernosum (P < 0.05 vs. injured controls). Although high concentration GDF-5 did not confer meaningful erectile recovery, this dose was more effective at decreasing transforming growth factor-beta than low-concentration GDF-5.

CONCLUSIONS

Intracavernous injection of low (0.4 microg) or intermediate-concentration GDF-5 (2 microg) was effective in preserving erectile function in a rat model of neurogenic erectile dysfunction. The underlying mechanism appears to involve neuron preservation and antiapoptosis.

Cavernous nerve repair with allogenic adipose matrix and autologous adipose-derived stem cells

OBJECTIVES

To investigate whether adipose-derived matrix seeded with adipose-derived stem cells (ADSC) can facilitate the repair of injured cavernous nerves (CNs).

METHODS

Human and rat adipose tissues were decellularized and fabricated into various forms, including adipose tissue-derived acellular matrix thread (ADMT). ADMT seeded with ADSC were transplanted into subcutaneous space and examined for signs of inflammation. ADSC-seeded ADMTs were then used to repair CN injury in rats, followed by assessment of histology and erectile function.

RESULTS

Adipose tissue can be fabricated into acellular matrices of various shapes and sizes, including threads and sheets. Seeding of ADMT occurred rapidly: within 24 hours, 55% of the surface was covered with ADSC and within 1 week, 90% was covered. Transplantation of the seeded ADMT into the subcutaneous space of an allogenic host showed no signs of inflammatory reaction. At 3 months after grafting into CN injury rats, approximately twice as many cells were found on seeded ADMT as on unseeded ADMT. The seeded ADMT also had various degrees of S100 and neuronal nitric oxide synthase expression, suggesting CN axonal ingrowth. Rats grafted with seeded ADMT overall had the best erectile function recovery when compared with those grafted with unseeded ADMT and those ungrafted. However, as a result of large variations, the differences did not reach statistic significance (P = .07).

CONCLUSIONS

Grafting of ADSC-seeded matrix resulted in a substantial recovery of erectile function and improvement of histology. However, further refinement of the matrix architecture is needed to improve the success rate.

Efficacy of a metalloproteinase inhibitor in spinal cord injured dogs

Matrix metalloproteinase-9 is elevated within the acutely injured murine spinal cord and blockade of this early proteolytic activity with GM6001, a broad-spectrum matrix metalloproteinase inhibitor, results in improved recovery after spinal cord injury. As matrix metalloproteinase-9 is likewise acutely elevated in dogs with naturally occurring spinal cord injuries, we evaluated efficacy of GM6001 solubilized in dimethyl sulfoxide in this second species. Safety and pharmacokinetic studies were conducted in naïve dogs. After confirming safety, subsequent pharmacokinetic analyses demonstrated that a 100 mg/kg subcutaneous dose of GM6001 resulted in plasma concentrations that peaked shortly after administration and were sustained for at least 4 days at levels that produced robust in vitro inhibition of matrix metalloproteinase-9. A randomized, blinded, placebo-controlled study was then conducted to assess efficacy of GM6001 given within 48 hours of spinal cord injury. Dogs were enrolled in 3 groups: GM6001 dissolved in dimethyl sulfoxide (n = 35), dimethyl sulfoxide (n = 37), or saline (n = 41). Matrix metalloproteinase activity was increased in the serum of injured dogs and GM6001 reduced this serum protease activity compared to the other two groups. To assess recovery, dogs were a priori stratified into a severely injured group and a mild-to-moderate injured group, using a Modified Frankel Scale. The Texas Spinal Cord Injury Score was then used to assess long-term motor/sensory function. In dogs with severe spinal cord injuries, those treated with saline had a mean motor score of 2 (95% CI 0–4.0) that was significantly (P<0.05; generalized linear model) less than the estimated mean motor score for dogs receiving dimethyl sulfoxide (mean, 5; 95% CI 2.0–8.0) or GM6001 (mean, 5; 95% CI 2.0–8.0). As there was no independent effect of GM6001, we attribute improved neurological outcomes to dimethyl sulfoxide, a pleotropic agent that may target diverse secondary pathogenic events that emerge in the acutely injured cord.

Cavernous smooth muscle hyperplasia in a rat model of hyperlipidaemia-associated erectile dysfunction

What's known on the subject? and what does the study add? Increased cavernous smooth muscle content has been repeatedly observed in rat models of hyperlipidaemia - associated erectile dysfunction. This study shows that the increased smooth muscle content is due to hyperplasia.

OBJECTIVE

• To investigate the structural changes, including possible smooth muscle hyperplasia, in the penis of a hyperlipidaemia-associated erectile dysfunction (ED) animal model.

MATERIALS AND METHODS

• Hyperlipidaemia was induced in rats through a high-fat diet. • Penile tissues of normal and hyperlipidaemic rats were stained with Alexa-488-conjugated phalloidin and/or with antibodies against rat endothelial cell antigen, neuronal nitric oxide synthase (nNOS), and collagen type IV (Col-IV) before image and statistical analyses were carried out. • The main outcome measures were the smooth muscle, endothelial, Col-IV and nNOS content of the corpus cavernosum.

RESULTS

• Phalloidin intensely stained all smooth muscle in the penis, revealing the circular and longitudinal components of cavernous smooth muscle (CSM). • The CSM content was significantly higher in the hyperlipidaemic than in the normal rats (P < 0.05). • Cell numbers in both circular and longitudinal CSM were significantly higher in the hyperlipidaemic than in the normal rats (P < 0.05). • Cavernous endothelial content was significantly lower in hyperlipidaemic than in normal rats (P < 0.05). • nNOS-positive nerves within the dorsal nerves, around the dorsal arteries, and in the corpora cavernosa were all significantly lower in the hyperlipidaemic than in the normal rats (P < 0.05).

CONCLUSIONS

• Hyperlipidaemia is associated with reduced nNOS-positive nerves, reduced endothelium, and increased CSM in the penis. • The increased CSM is attributable to hyperplasia. • These structural changes may explain why hyperlipidaemic men are more likely to develop ED.

The effect of intracavernosal growth differentiation factor-5 therapy in a rat model of cavernosal nerve injury

OBJECTIVE

To determine whether the intracavernosal application of growth differentiation factor-5 (GDF-5) influences nerve regeneration and erectile function after cavernosal nerve injury in a rat model.

MATERIALS AND METHODS

Thirty-two male Sprague-Dawley rats were randomly divided into four equal groups: eight had a sham operation (uninjured controls), while 24 had bilateral cavernosal nerve crush. The crush-injury groups were treated at the time of injury with an impregnated collagen sponge implanted into the right corpus cavernosum. The sponge contained no GDF-5 (injured controls), 2 microg (low concentration), or 20 microg GDF-5 (high concentration). Erectile function was assessed by cavernosal nerve electrostimulation at 8 weeks. Midshaft penile tissue samples were histochemically evaluated for neuronal nitric oxide synthase (nNOS)-containing fibres in the dorsal penile nerve.

RESULTS

There was no erectile dysfunction in the uninjured control group, as shown by a mean (sem) maximal increase in intracavernosal pressure (ICP) of 149.5 (17.0) cmH(2)O on stimulation. By comparison, the ICP decreased in the injured control group, by 21.3 (6.7) cmH(2)O. After cavernosal nerve injury, the recovery of erectile function was greatest in the low-concentration GDF-5 group; the maximum ICP increase was 40.8 (13.3) cmH(2)O, vs 24.3 (5.9) cmH(2)O for 20 microg GDF-5. Histologically, the low-concentration group had significantly more nNOS-containing nerve fibres, at 163 (24.7), than the high-concentration group, at 76 (17.3), or injured controls, at 67 (23.8). By contrast, the uninjured controls had a mean of 538 (40.6) nerve fibres in the dorsal nerve.

CONCLUSION

Bilateral cavernosal nerve crush resulted in erectile dysfunction with accompanying neurological changes in the rat. The intracavernosal application of GDF-5 enhanced the recovery of erectile function and n-NOS nerve preservation, with a 2-microg dose giving the most promising results.

Neurturin enhances the recovery of erectile function following bilateral cavernous nerve crush injury in the rat

Background

The molecular mechanisms responsible for the survival and preservation of function for adult parasympathetic ganglion neurons following injury remain incompletely understood. However, advances in the neurobiology of growth factors, neural development, and prevention of cell death have led to a surge of clinical interest for protective and regenerative neuromodulatory strategies, as surgical therapies for prostate, bladder, and colorectal cancers often result in neuronal axotomy and debilitating loss of sexual function or continence. In vitro studies have identified neurturin, a glial cell line-derived neurotrophic factor, as a neuromodulator for pelvic cholinergic neurons. We present the first in vivo report of the effects of neurturin upon the recovery of erectile function following bilateral cavernous nerve crush injury in the rat.

Methods

In these experiments, groups (n = 8 each) consisted of uninjured controls and animals treated with injection of albumin (blinded crush control group), extended release neurotrophin-4 or neurturin to the site of cavernous nerve crush injury (100 μg per animal). After 5 weeks, recovery of erectile function (treatment effect) was assessed by cavernous nerve electrostimulation and peak aortic pressures were measured. Investigators were unblinded to specific treatments after statistical analyses were completed.

Results

Erectile dysfunction was not observed in the sham group (mean maximal intracavernous pressure [ICP] increase of 117.5 ± 7.3 cmH₂O), whereas nerve injury and albumin treatment (control) produced a significant reduction in ICP elevation of 40.0 ± 6.3 cmH₂O. Neurturin facilitated the preservation of erectile function, with an ICP increase of 55% at 62.0 ± 9.2 cmH₂O (p < 0.05 vs control). Extended release neurotrophin-4 did not significantly enhance recovery of erectile function with an ICP change of 46.9 ± 9.6. Peak aortic blood pressures did not differ between groups. No significant pre- and post-treatment weight differences were observed between control, neurotrophin-4 and neurturin cohorts. All animals tolerated the five-week treatment course.

Conclusion

Treatment with neurturin at the site of cavernous nerve crush injury facilitates recovery of erectile function. Results support further investigation of neurturin as a neuroprotective and/or neuroregenerative agent facilitating functional recovery after cavernous or other pelvic autonomic nerve injuries.

Comparison of spinal cord contusion and transection: functional and histological changes in the rat urinary bladder

OBJECTIVE

To compare the effect of complete transection (tSCI) and contusion spinal cord injury (cSCI) on bladder function and bladder wall structure in rats.

MATERIALS AND METHODS

A total of 30 female Sprague-Dawley rats were randomly divided into three equal groups: an uninjured control, a cSCI and a tSCI group. The cSCI group underwent spinal cord contusion, while the tSCI group underwent complete spinal cord transection. At 6 weeks post-injury, 24-h metabolic cage measurement and conscious cystometry were performed.

RESULTS

Conscious cystometry analysis showed that the cSCI and tSCI groups had significantly larger bladder capacities than the control group. The cSCI group had significantly more non-voiding detrusor contractions than the tSCI group. Both injury groups had more non-voiding contractions compared with the control group. The mean threshold pressure was significantly higher in the tSCI group than in the control and cSCI groups. The number of voids in the tSCI group was lower compared with the control group. Metabolic cage analysis showed that the tSCI group had larger maximum voiding volume as compared with the control and cSCI groups. Vesicular acetylcholine transporter/smooth muscle immunoreactivity was higher in the control than in the cSCI or tSCI rats. The area of calcitonin gene-related peptide staining was smaller in the tSCI group than in the control or cSCI groups.

CONCLUSIONS

Spinal cord transection and contusion produce different bladder phenotypes in rat models of SCI. Functional data suggest that the tSCI group has an obstructive high-pressure voiding pattern, while the cSCI group has more uninhibited detrusor contractions.

The potential of hormones and selective oestrogen receptor modulators in preventing voiding dysfunction in rats

OBJECTIVE

To investigate whether oestrogen, selective oestrogen receptor modulators (SERMs), and growth hormone (GH) can prevent the development of voiding dysfunction in a postpartum postmenopausal rat model of voiding dysfunction.

MATERIALS AND METHODS

Immediately after spontaneous delivery, nine primiparous Sprague-Dawley rats served as uninjured controls (sham group) and 54 underwent intravaginal balloon dilation. On day 7, the 54 subject rats underwent bilateral ovariectomy. A week later, six treatment groups of nine rats were randomized to receive: normal saline (injured control group), 17beta-oestradiol (E(2)), raloxifene, levormeloxifene, GH, or GH + E(2). The treatment groups received daily subcutaneous injections for 3 weeks. The effects of hormone treatment were examined by conscious cystometry at the end of the study. Voiding dysfunction was defined to include overactive bladder and sphincter deficiency.

RESULTS

The sham rats had a mean (sd) voiding frequency of 3 (0.87) times in 10 min and a bladder capacity of 0.43 (0.13) mL with smooth cystometry curves. The number of rats in each treatment group (each group contained nine rats) that had voiding dysfunction was as follows: E(2), three; raloxifene, six; levormeloxifene, four; and controls, four (P > 0.05 among the groups). Only one rat in the GH-treated group and no rats in the GH + E(2)-treated group had voiding dysfunction, which was significantly less in the GH + E(2)-treated group than in the controls (P = 0.041).

CONCLUSION

This functional data suggest that the development of voiding dysfunction can be prevented by short-term administration of GH and GH + E(2) in our rat model. SERMs and E(2) alone seem to have no therapeutic effect.

Tunica albuginea allograft: a new model of LaPeyronie's disease with penile curvature and subtunical ossification

The pathophysiology of LaPeyronie's disease (PD) is considered to be multifactorial, involving genetic predisposition, trauma, inflammation and altered wound healing. However, these factors have not yet been validated using animal models. In this study, we have presented a new model obtained by tunica albuginea allograft. A total of 40, 16-week-old male rats were used. Of these, 8 rats served as controls and underwent a 10 × 2-mm-wide tunical excision with subsequent autografting, whereas the remaining 32 underwent the same excision with grafting of the defect with another rat's tunica. Morphological and functional testing was performed at 1, 3, 7 and 12 weeks after grafting. Intracavernous pressure, the degree of penile curvature and elastic fiber length were evaluated for comparison between the allograft and control groups. The tissues were obtained for histological examination. The penile curvature was significantly greater in the allografted rats as compared with the control rats. The erectile function was maintained in all rats, except in those assessed at 12 weeks. The elastin fiber length was decreased in the allografted tunica as compared to control. SMAD2 expression was detected in the inner part of the allograft, and both collagen-II- and osteocalcin-positive cells were also noted. Tunica albuginea (TA) allograft in rats is an excellent model of PD. The persistence of curvature beyond 12 weeks and the presence of ossification in the inner layer of the TA were similar to those observed in men with PD. Validation studies using this animal model would aid understanding of the PD pathophysiology for effective therapeutic interventions.

Cryopreservation of prostate cancer tissue during routine processing of fresh unfixed prostatectomy specimen: demonstration and validation of a new technique

BACKGROUND

Most molecular techniques currently require fresh frozen tumor tissue, which in the case of prostatectomy specimen is a challenge to obtain for a variety of intrinsic reasons. Prostate cancers are usually located in the organ periphery and hence meticulous attention has to be paid to the relation between the tumor and the surgical margin. In this article we describe a new technique that allows to obtain fresh frozen tumor material in rather large quantities and without jeopardizing diagnostic accuracy.

METHOD

An inner triangle, representing roughly 50% of the entire prostate tissue, is removed from native prostatectomy specimen and cryopreserved, leaving the periphery of the organ for routine histomorphological analysis. We have validated the technique using a series of 180 archived radical prostatectomy specimen that had been studied by histology in their entirety, as well as 42 prostatectomy specimen worked-up by the new technique.

RESULTS

The described technique is effective, yielding frozen tumor tissue in 84.2% of unilateral (<or=pT2b) and in 91.8% of bilateral (pT2c) carcinomas. The number of tumor containing tissue blocks ranged from 1 to 7 blocks per carcinoma (mean 5.6 +/- 3.2). The remaining peripheral tissue portion subjected to histological analysis allowed to estimate total tumor volume with a high degree to confidentiality (r(2) >or= 0.90 by linear regression analysis). The number of blocks to be routinely examined for each prostatectomy specimen is significantly reduced, thus saving costs without loss of diagnostic accuracy.

CONCLUSION

The described technique for prostate cancer cryoconservtion is feasible, highly standardized, effective, safe, and economic.

Modulation of smooth muscle tonus in the lower urinary tract: interplay of myosin light-chain kinase (MLCK) and MLC phosphatase (MLCP)

OBJECTIVE

To assess and compare the expression and activity of myosin light-chain kinase (MLCK) and MLC phosphatase (MLCP) in rat bladder and urethra.

MATERIALS AND METHODS

Bladder and urethral smooth muscles were obtained from 2-month-old female Sprague-Dawley rats. They were analysed by real-time polymerase chain reaction for the mRNA expression of MLCK and myosin phosphatase-targeting subunit of protein phosphatase type 1 (MYPT1, a subunit of MLCP). Levels of MLCK and MYPT1 mRNA expression were determined as a ratio to the expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The tissues were also analysed by Western blotting for MLCK and MYPT1 protein expression as a ratio to the expression of β-actin. A two-step enzymatic activity assay using phosphorylated and dephosphorylated smooth muscle myosin was used to assess MLCK and MLCP activity.

RESULTS

MLCK mRNA expression was higher in the bladder than in the urethra [mean (sd) ratio to GAPDH: 0.26 (0.17) vs 0.14 (0.12); P = 0.09]. MYPT1 mRNA expression was significantly higher in the bladder than in the urethra [mean (sd) ratio to GAPDH: 2.31 (1.04) vs 0.56 (0.36); P = 0.001]. Expression of both MLCK and MYPT1 protein was significantly higher in the bladder compared with the urethra [mean (sd) ratio to β-actin: 1.63 (0.25) vs 0.91 (0.29) and 0.97 (0.10) vs 0.37 (0.29), respectively; both P < 0.001]. Enzymatic assay identified significantly greater MLCK activity in the bladder than in the urethra. While, MLCP activity was lower in the bladder than in the urethra.

CONCLUSION

In healthy young female rats, MLCK activity is higher and MLCP activity is lower in the bladder relative to the urethra. These differences probably play a role in modulating the functional differences between bladder and urethral smooth muscle tone.