Cavernosal Nerve Injury Research Articles

Restoring erectile function by combined treatment with JNK inhibitor and HDAC inhibitor in a rat model of cavernous nerve injury.

The main pathophysiologic conditions of erectile dysfunction (ED) after radical prostatectomy are considered to be corporal fibrosis and apoptosis induced by cavernosal nerve (CN) injury. In a rat model of CN crush injury (CNCI), we investigated whether combination treatment with JNK inhibitor (JNKi), SP600125, and HDAC inhibitor (HDACi), suberoylanilide-hydroxamic-7 acid (SAHA), for 2weeks after CNCI would restore erectile function by suppressing fibrosis and apoptosis through normalization of JNK and HDAC pathways. Seventy 12-week-old rats were randomly divided into five groups: Sham surgery, CNCI alone, CNCI treated with daily intraperitoneal injection of 10mg/kg JNKi, CNCI treated with daily oral administration of 25.0mg/kg HDACi, and CNCI daily treated with a combination. Two weeks after CNCI, we investigated the erectile response to electrostimulation and conducted histological staining, caspase-3 activity assay, and western blot analysis. CNCI alone resulted in significantly reduced intracavernosal pressure/mean arterial pressure (MAP) and area under the curve/MAP, decreased smooth muscle (SM)/collagen ratio and SM content, higher caspase-3 activity, and increased protein levels of total HDAC3, transforming growth factor (TGF)-β, fibronectin, and c-Jun phosphorylation, compared with the Sham surgery. The CNCI groups exposed to JNKi, HDACi or both showed improvements in erectile-responses and SM/collagen ratio, compared to the CNCI alone. The combined treatment showed additional improvement in erectile responses at 1.0V stimulation and in SM/collagen ratio compared to the single agent treatment. SM content, caspase-3 activity, and c-Jun phosphorylation improved in the two CNCI groups exposed to JNKi. The two CNCI groups exposed to HDACi showed normalization of protein levels of HDAC3, fibronectin, and TGF-β. The combined administration of JNKi and HDACi during the acute phase after CNCI in rats can preserve ED by suppressing cavernosal fibrosis and apoptosis by normalizing the HDAC/TGF-β and JNK pathways.

Transpelvic Magnetic Stimulation Enhances Penile Microvascular Perfusion in a Rat Model: A Novel Interventional Strategy to Prevent Penile Fibrosis after Cavernosal Nerve Injury.

PurposePenile microvascular dysfunction is a known contributor to erectile dysfunction (ED) and penile fibrosis has been shown to impair microvascular perfusion (MVP). Our objectives were to: (i) determine beneficial effects of TPMS to modulate penile MVP, (ii) determine its mechanism, (iii) evaluate impact of cavernosal nerve injury (CNI) on penile MVP, and (iv) determine time-course of cavernosal tissue elastin changes after CNI in rats.Materials and MethodsAdult male rats (n=5) were anesthetized and subjected to TPMS (13%, 15%, and 17%) and MVP changes were recorded using laser speckle contrast imaging (LSCI). Another group of male rats were subjected to either bilateral cavernosal nerve injury (CNI; n=7) or sham surgery (n=7). After recovery, animals were monitored for MVP using LSCI before and after TPMS. Rat penile tissues were harvested and analyzed for fibrosis using a marker for elastin.ResultsRat TPMS resulted in a stimulus dependent increase in MVP; maximal perfusion was observed at 17%. L-N(G)-Nitroarginine methyl ester (L-NAME) resulted in a marked decrease in TPMS induced MVP increase (393.33 AU vs. 210.67 AU). CNI resulted in 40% to 50% decrease in MVP. CNI produced a remarkable increase in elastin deposits that are noticeable throughout the cavernosal tissues post injury.ConclusionsTPMS is a novel and non-invasive intervention to improve penile MVP after CNI. Potential application includes treatment of ED and sexual function preservation following cancer treatment, possibly through improved penile hemodynamics that might help prevent penile hypoxia and fibrosis.

The Role of LIM Kinase in the Male Urogenital System.

The LIM kinases (LIMK1 and LIMK2), known as downstream effectors, and the Rho-associated protein kinase (ROCK), a regulator of actin dynamics, have effects on a diverse set of cellular functions. The LIM kinases are involved in the function of the male urogenital system by smooth muscle contraction via phosphorylation of cofilin and subsequent actin cytoskeleton reorganization. Although LIMK1 and LIMK2 share sequence similarities as serine protein kinases, different tissue distribution patterns and distinct localization during cell cycle progression suggest other biological functions for each kinase. During meiosis and mitosis, the LIMK1/2–cofilin signaling facilitates the orchestrated chromatin remodeling between gametogenesis and the actin cytoskeleton. A splicing variant of the LIMK2 transcript was expressed only in the testis. Moreover, positive signals with LIMK2-specific antibodies were detected mainly in the nucleus of the differentiated stages of germ cells, such as spermatocytes and early round spermatids. LIMK2 plays a vital role in proper spermatogenesis, such as meiotic processes of spermatogenesis after puberty. On the other hand, the literature evidence revealed that a reduction in LIMK1 expression enhanced the inhibitory effects of a ROCK inhibitor on the smooth muscle contraction of the human prostate. LIMK1 may have a role in urethral obstruction and bladder outlet obstruction in men with benign prostatic hyperplasia. Moreover, LIMK1 expression was reduced in urethral stricture. The reduced LIMK1 expression caused the impaired proliferation and migration of urethral fibroblasts. In addition, the activated LIMK2–cofilin pathway contributes to cavernosal fibrosis after cavernosal nerve injury. Recent evidence demonstrated that short-term inhibition of LIMK2 from the immediate post-injury period prevented cavernosal fibrosis and improved erectile function in a rat model of cavernosal nerve injury. Furthermore, chronic inhibition of the LIMK2–cofilin pathway significantly restrained the cavernosal veno-occlusive dysfunction, the primary pathophysiologic mechanism of post-prostatectomy erectile dysfunction through suppressing fibrosis in the corpus cavernosum. In conclusion, the LIM kinases–cofilin pathway appears to play a role in the function of the male urogenital system through actin cytoskeleton reorganization and contributes to the pathogenesis of several urogenital diseases. Therefore, LIM kinases may be a potential treatment target in urogenital disorder.

Combination Therapy with a JNK Inhibitor and Hepatocyte Growth Factor for Restoration of Erectile Function in a Rat Model of Cavernosal Nerve Injury: Comparison with a JNK Inhibitor Alone or Hepatocyte Growth Factor Alone

We determined if combined administration of JNK-inhibitors and HGF (hepatocyte-growth-factor) would restore erectile-function through both antiapoptotic and regenerative effects in a rat model of cavernous-nerve-crush-injury (CNCI), and compared the results with administration of JNK-inhibitor alone or HGF alone. We randomized 70 rats into 5 groups: sham-surgery-group (S), CNCI (I) group, a group treated with once-daily intraperitoneal-administration of 10.0-mg/kg of JNK-inhibitors (J), a twice-weekly intracavernosal-administration of 4.2-μg HGF group (H), and a combined-treatment with 10.0-mg/kg JNK-inhibitors and 4.2-μg HGF group (J+H). We investigated erectile-responses to electrostimulation, histological-staining, caspase-3-activity-assay, and immunoblotting at two-weeks postoperatively. The three treatment groups showed improvements in erectile-responses (ICP/MAP and AUC/MAP ratios) compared to Group-I. The erectile-responses in Group-J+H were greater than those in Group-J or Group-H. The erectile-responses in Group-J+H were generally normalized. Caspase-3-activity and cJun-phosphorylation in Group-J and Group-J+H improved compared to Group-I, whereas caspase-3-activity in Group-H partially improved. Protein-expression of PECAM-1, eNOS-phosphorylation, and smooth-muscle content in Group-J+H were normalized, although those in Group-J or Group-H were partially restored. Combination therapy with JNK-inhibitors and HGF can generally normalize erectile-function through anti-apoptosis and preservation of endothelium or SM in rat CNCI model. The combined treatment appears to be superior to the respective agent alone in terms of therapeutic effects.

Long noncoding RNA H19 promotes the apoptosis of corpus cavernsum smooth muscle cells after cavernosal nerve injury via JNK signalling pathway.

JNK/ Bcl-2/ Bax pathway participates in corpus cavernosal smooth muscle cells apoptosis during early period after cavernosal nerve (CN) crush injury (CNCI). Nevertheless, the regulation mechanisms of long noncoding RNA H19 in apoptosis during early stage after CN injury are still poorly understood. The rats in sham group were not direct injury to the CNs. The rats in CNCI group were performed to bilateral CN crush injury. The ICP/MAP rate and smooth muscle content were significantly lower than that in the sham group. Primary CCSMCs were prepared from the tissues samples after completing erectile function detection. Phosphorylated-JNK level was increased significantly, and the expression of Bax and Bcl-2 was elevated and declined in CNCI group respectively. Except for Bcl-2, the mRNA levels of H19, JNK and Bax were significantly increased in CNCI group. After H19 siRNA transfection, for the mRNA and protein levels, JNK and Bax were declined, while Bcl-2 was enhanced. LncRNA H19 might be involved in regulation of Bcl-2, Bax via JNK signalling pathway in CCSMCs apoptosis after CN injury.

P0475 - Strategy for the restoration of erectile function by a combination of anti-apoptotic effects by a JNK inhibitor and regeneration by hepatocyte growth factor in a rat model of cavernosal nerve injury

P0475 - Strategy for the restoration of erectile function by a combination of anti-apoptotic effects by a JNK inhibitor and regeneration by hepatocyte growth factor in a rat model of cavernosal nerve injury

Rectification of cavernosal fibrosis and veno‐occlusive dysfunction by administration of suberoylanilide hydroxamic acid in a rat model of cavernosal nerve injury: Comparison with a PDE5 inhibitor

Cavernosal fibrosis, which is induced by cavernosal nerve (CN) injury and progresses with time, is the main cause of cavernosal veno-occlusive dysfunction (CVOD) after radical prostatectomy. To determine whether daily oral administration of suberoylanilide hydroxamic acid (SAHA; vorinostat) for 5-weeks from the immediate post-injury period after CN injury would rectify CVOD by suppressing cavernosal fibrosis and normalizing HDAC pathway in a rat model of CN crush injury (CNCI) and to compare the results with those obtained using chronic administration of PDE5-inhibitors (a positive control). Fifty-six 12-week-old rats were randomized into the four groups: sham surgery (S), CNCI (I), and CNCI treated with daily administration of 25.0mg/kg SAHA (V) or 20.0mg/kg udenafil (P). Group-V and Group-P received the respective treatment for 5-weeks from the following day after CNCI. At 5weeks after surgery, dynamic infusion cavernosometry (DIC), histological staining, and Western blot analysis were performed. Group-I had a significantly decreased papaverine response, higher maintenance rate or drop rate, lower smooth muscle (SM)/collagen ratio, decreased SM content, and increased protein expression of HDAC2, HDAC3, TGF-β1, and collagen-1, compared with Group-S. The three DIC parameters in Group-V and Group-P significantly improved compared to those in Group-I. Except for the maintenance rate, the improvement in papaverine response and drop rate in Group-V was not significantly different from that in Group-P. Group-V and Group-P showed the rectification of SM/collagen ratio and protein expression of TGF-β1 or collagen-1. SM content was improved in Group-P, but not in Group-V. Group-V showed the normalization of protein expression of both HDAC2 and HDAC3, whereas protein expression of only HDAC2 was partially restored in Group-P. Treatment strategies targeting the HDAC pathway might be helpful to alleviate CVOD induced by CN injury. According to our data, chronic administration of SAHA improves post-injury CVOD by suppressing cavernosal fibrosis via rectifying the HDAC/TGF-β1 pathway in nerve-injured rats, comparable to that with PDE5 inhibitors.

619 - Restoration of cavernosal veno-occlusive function through chronic administration of both a JNK inhibitor and a LIMK2 inhibitor in a rat model of cavernosal nerve injury: A comparison with a PDE5 inhibitor

619 - Restoration of cavernosal veno-occlusive function through chronic administration of both a JNK inhibitor and a LIMK2 inhibitor in a rat model of cavernosal nerve injury: A comparison with a PDE5 inhibitor

Ziziphus jujube ameliorated cavernosal oxidative stress and fibrotic processes in cavernous nerve injury-induced erectile dysfunction in a rat model.

The aim of this study was to investigate potential antioxidant and antifibrotic effects of Ziziphus jujube (ZJ) in a cavernosal nerve injury (CNI)-induced erectile dysfunction (ED) rat model. Forty-eight male rats were assigned to six-sized groups as group 1: sham-operated; group 2: sham-operated+low-dose ZJ (200mg/kg); group 3: sham-operated+high-dose ZJ (400mg/kg); group 4: CNI+distilled water; group 5: CNI+low-dose ZJ; and group 6: CNI+high-dose ZJ. At the end of 2weeks, intracardiac blood was taken and rats were sacrificed. For biochemical analysis, cavernosal transforming growth factor-beta-1, collagen type I and type 3, fibronectin, α and β actin were examined in plasma and cavernosa. Superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and prolidase levels were measured in serum to evaluate antioxidant effect of ZJ. Histopathological examination of tissues revealed that highest fibrosis rate was in group 4 (66.84%). Collagen 1 and 3, alpha and beta actin, fibronectin levels were significantly different among groups (p<.05). Differences between plasma SOD, CAT, MDA and prolidase were also significant among those groups (p<.05). In this study, antioxidant and antifibrotic effects of ZJ were determined in the corporal tissue after CNI. It is thought that ZJ may be beneficial on ED patients especially after radical pelvic surgeries.

036 A Trial of Low-Intensity Shockwave Therapy for Penile Rehabilitation After Radical Prostatectomy

Erectile dysfunction (ED) is a common complication of radical prostatectomy, usually due to nerve damage. Low-intensity shockwave therapy (LISWT) is an encouraging new treatment for men with vasculogenic ED, but the role of LISWT in the post-prostatectomy setting is unknown, as existing LISWT trials excluded men who underwent prostatectomy. Interestingly, rat models of cavernosal nerve injury suggest LISWT may restore penile blood flow via revascularization and neuronal regeneration. We hypothesize that LISWT-based penile rehabilitation will accelerate recovery of erectile function following nerve-sparing radical prostatectomy. To evaluate the hypothesis that PDE5i therapy combined with LISWT, delivered early in the post-prostatectomy period, will lead to more rapid recovery of erectile function compared to men treated with PDE5i alone. This is an interim analysis of an IRB approved, non-randomized trial of LISWT for penile rehabilitation. Patients were identified for inclusion if their pre-operative sexual health inventory for men (SHIM) score was ≥ 17 and they underwent a bilateral nerve-sparing prostatectomy at our academic referral hospital. Exclusion criteria included: concurrent use of intracavernosal injections or vacuum erectile device; or Gleason Grade Group ≥ 4 disease. Men were enrolled in either the LISWT arm (intervention) or the PDE5i only arm (control) at their own discretion. Beginning two weeks post-operatively, intervention patients received six consecutive LISWT sessions delivered once weekly using the Zimmer enPuls 2.0 device. During each session, settings were 90 mJ and 15 Hz to deliver a total of 10,000 “shocks” distributed to the corpora and cavernosal neurovascular bundles bilaterally. SHIM and erection hardness score (EHS) surveys were mailed to both cohorts at 6, 12, and 24-weeks post-operatively. All patients were prescribed a PDE5i at the discretion of their treating surgeon.

Re: Chronic Administration of LIMK2 Inhibitors Alleviates Cavernosal Veno-Occlusive Dysfunction through Suppression of Cavernosal Fibrosis in a Rat Model of Erectile Dysfunction after Cavernosal Nerve Injury.

Re: Chronic Administration of LIMK2 Inhibitors Alleviates Cavernosal Veno-Occlusive Dysfunction through Suppression of Cavernosal Fibrosis in a Rat Model of Erectile Dysfunction after Cavernosal Nerve Injury.

Combination of LIM-kinase 2 and Jun Amino-terminal Kinase Inhibitors Improves Erectile Function in a Rat Model of Cavernous Nerve Injury

ObjectiveTo determine if combined administration of LIMK2 and JNK inhibitors in a rat model of erectile dysfunction induced by cavernosal nerve (CN) injury could restore erectile function by suppressing both cavernosal apoptosis and fibrosis via rectification of molecular pathways related to the structural alterations. MethodsSixty 12-week-old male Sprague-Dawley rats were categorized into 4 groups: (1) Sham-surgery (Sham) group, (2) CN-crush-injury (CNCI), (3) CNCI group (CNCI+L+1.0J) treated with a combination of 10.0 mg/kg LIMK2-inhibitors and low-dose (1.0 mg/kg) JNK-inhibitors, and (4) CNCI group (CNCI+L+10.0J) treated with a combination of 10.0 mg/kg LIMK2-inhibitors and a high dose (10.0 mg/kg) of JNK-inhibitors. Ten days after surgery, erectile response, histological-studies, and Western-blot was investigated. ResultsThe CNCI group showed a reduced maximal ICP/MAP or AUC/MAP, decreased immunohistochemical-staining of α-SMA, decreased SM/collagen ratio, increased phospho-cJun-positive apoptotic cells, increased phospho-LIMK2-positive fibroblasts, increased cJun-phosphorylation, increased LIMK2/Cofilin-phosphorylation, decreased Bcl-2/Bax ratio, and increased protein-expression of fibronectin, compared to the Sham group. Both the CNCI+L+1.0J and CNCI+L+10.0J groups showed improvements in erectile-responses, content of cavernosal α-SMA, number of phospho-cJun-positive apoptotic cells, Bcl-2/Bax ratio and cJun phosphorylation. Their improvements in the CNCI+L+10.0J group showed a tendency to be greater than those in the CNCI+L+1.0J group. Also, in the 2 treatment groups, rectification of SM/collagen ratio, number of phospho-LIMK2-positive fibroblasts, LIMK2/Cofilin-phosphorylation, and protein-expression of fibronectin was observed. ConclusionThis study suggests that combined inhibition of JNK and LIMK2 may improve erectile function by suppressing cavernosal apoptosis and fibrosis via restoration of cJun/Bcl-2/Bax and LIMK2/Cofilin pathways at 10 days after CN injury.

Chronic administration of LIMK2 inhibitors alleviates cavernosal veno-occlusive dysfunction through suppression of cavernosal fibrosis in a rat model of erectile dysfunction after cavernosal nerve injury.

We evaluated whether chronic administration of LIMK2-inhibitors could improve erectile function by alleviating CVOD through suppressing cavernosal fibrosis in a rat model of cavernosal nerve crush-injury (CNCI). Forty-two 12-week-old rats were equally categorized into the three groups: sham-surgery (S), CNCI (I), and CNCI treated with LIMK2-inhibitors (L). The L-group was treated with daily intraperitoneal injection of LIMK2-inhibitors (10.0 mg/kg) for 30-days after surgery. Erectile function was assessed using dynamic-infusion-cavernosometry (DIC). Penile tissue was processed for Masson’s-trichrome staining, Western-blotting, and double immunofluorescence. The I-group showed significantly higher maintenance and drop rates as well as lower papaverine response, compared to the S-group. Chronic inhibition of LIMK2 in the L-group significantly improved the DIC parameters compared to those in the I-group, although the parameters were not completely restored to normal control values. Also, the I-group showed a reduced smooth muscle (SM)-to-collagen ratio, decreased immunohistochemical staining for α-SM-actin, increased number of fibroblasts positive for phosphorylated Cofilin, increased LIMK2/Cofilin phosphorylation and increased protein expression of Collagen-1 or Fibronectin, compared to the S-group. The L-group showed significant improvements in SM/collagen ratio and the deposition of Collagen-1 or Fibronectin compared to the I-group, although not completely normalized. According to the densitometry and confocal microscopy results, the L-group showed restoration of LIMK2/Cofilin phosphorylation and amount of fibroblasts positive for phosphorylated Cofilin to the normal control value. In conclusion, chronic inhibition of LIMK2 can improve CVOD and ED by alleviating cavernosal fibrosis via normalizing the LIMK2/Cofilin pathway.

Bupropion use in the first trimester of pregnancy

Cavernosal fibrosis is an important pathologic condition leading to erectile dysfunction (ED). The etiologies of cavernosal fibrosis include aging, diabetes mellitus, castration, cavernosal nerve injury during radical prostatectomy, hypertension, and Peyronie disease.To summarize published studies investigating suppression of cavernosal fibrosis in rat models of ED of various etiologies.A literature search was conducted using PubMed. Relevant studies were identified using search terms such as erectile dysfunction, penis, fibrosis, and rat models.We reviewed representative literature studies on the mechanisms and suppression of cavernosal fibrosis in rat models of ED.The underlying mechanisms and potential therapeutic strategies suggested thus far for cavernosal fibrosis in rat models of ED were as follows. For age-related ED involving oxidative stress and tumor growth factor-β1 (TGF-β1)–driven pathways such as RhoA-ROCK1-LIMK2-cofilin or p42-44 and mitogen-activated protein kinase, proposed therapeutic strategies included phosphodiesterase type 5 inhibitors (PDE5Is), kallikrein-kinin system stimulators, and calorie restriction. For diabetes-related ED involving angiotensin-II– and TGF-β1–driven Smad and non-Smad pathways, TGF-β1-Wnt10b, and histone deacetylase (HDAC)-TGF-β1 pathways, positive therapeutic results were obtained with PDE5Is, TGF-β1 antagonists, HDAC inhibitors, antioxidants, sphingosine-1-phosphate receptor modulators (fingolimod), angiotensin-II antagonists, stem cell therapy, and antidiabetic drugs. For cavernosal nerve injury-associated ED involving TGF-β1–driven pathways (Smad or RhoA-ROCK1-LIMK2-cofilin), Sonic hedgehog signaling, angiotensin-II–Smad, and HDAC4–TGF-β1–Smad signaling triggered by cavernosal hypoxia, PDE5Is, angiotensin-II antagonists, stem cell therapy, HDAC inhibitors, Sonic hedgehog administration, ROCK inhibitors, and LIMK2 inhibitors have shown positive results. For testosterone deficiency-associated ED, TGF-β1–driven pathways were found to be responsive to testosterone supplementation. For hypertensive ED, positive therapeutic results were obtained with angiotensin-II antagonists. For Peyronie disease involving TGF-β1 or myostatin signaling, proposed therapeutic strategies included intra-tunical injection of TGF-β receptor inhibitors or adipose tissue-derived stem cells and HDAC2 small hairpin RNA.Several signaling pathways appear to be responsible for the development of cavernosal fibrosis related to ED of various etiologies. Some therapeutic success has been achieved in animal models, but further research focusing on mechanism-specific targeted therapies is needed.Cho MC, Song WH, Paick J-S. Suppression of Cavernosal Fibrosis in a Rat Model. Sex Med Rev 2018;6:572–582.

Pioglitazone's beneficial effects on erectile function preservation after cavernosal nerve injury in the rat are negated by inhibition of the insulin-like growth factor-1 receptor: a preclinical study.

To determine if the insulin-like growth factor-1 (IGF-1) pathway is involved in the improvement in erectile function recovery in rats after nerve crush injury treated with pioglitazone (Pio). Sprague-Dawley rats were divided into four groups. The first group received sham operation (n = 5). The second group underwent bilateral cavernous nerve injury (BCNI, n = 7). The third group received BCNI and Pio treatment (BCNI + Pio, n = 7), whereas the fourth group underwent BCNI with Pio treatment and IGF-1 inhibition (BCNI + Pio + JB-1, n = 7). The IGF-1 receptor (IGF-1R) was inhibited by JB-1, a small molecular antagonist of the receptor. After 14 days of treatment, erectile function was measured via intracorporal pressure normalized to mean arterial pressure (ICP/MAP) and the major pelvic ganglion and cavernous nerve harvested for western blot and immunohistochemistry (IHC) of phosphorylated-IGF-1Rβ (p-IGF-1Rβ), phosphorylated-ERK1/2 (p-ERK1/2), and neuronal NOS (nNOS). BCNI + Pio animals exhibited improvements in ICP/MAP, similar to Sham animals, and BCNI + Pio + JB-1 rats demonstrated a reduced ICP/MAP similar to BCNI-only rats at all measured voltages. Western blot results showed upregulation of p-IGF-1Rβ was observed in the BCNI + Pio group. Low levels of p-ERK1/2 were seen in the JB-1-treated animals. The immunoblot results were supported by IHC findings. Intense IHC staining of nNOS was detected in the BCNI + Pio group. The group treated with JB-1 showed minimal protein expression of p-ERK1/2, nNOS, and p-IGF-1Rβ. Pio improves erectile function in rats undergoing BCNI via an IGF-1-mediated pathway.

In Vivo Tracking of Mesenchymal Stem Cell in Rat Genitalia with Erectile Dysfunction Labeled by Superparamagnetic Iron Oxide Using Magnetic Resonance Imaging and Its Therapeutic Effect

Background: Molecular imaging with nanoparticles makes non-invasive monitoring of target cells without sacrifice of subjects and repeated evaluation possible. Objectives: To evaluate the imaging feasibility of a rat animal model with erectile dysfunction (ED) by bilateral cavernosal nerve injury using human mesenchymal stem cells (MSCs) labeled with superparamagnetic iron oxide (SPIO) and simultaneously to evaluate the beneficial effect of MSCs on ED. Materials and Methods: Thirty-six rats were injected with MSCs labeled with SPIO particle into the corpus cavernosum after bilateral cavernosal nerve injury. In vivo MR imaging was serially performed up to 16 weeks using 1.5 T clinical scanner. After MR imaging, the penile specimens were evaluated for the expression of transforming growth factor-β1 (TGF-β1) by polymerase chain reaction. Results: MR imaging showed a drop in signal intensity at the injection site in the stem cell-injected group. The size of hypointensity was decreased in MSC-injected group in a time-dependent manner; whereas, signal void was not detected at the injection site in the control group. In addition, polymeric chain reaction (PCR) analyses of penile tissues from both groups revealed that the mRNA expression of TGF-β1 was significantly decreased in MSC-injected groups after 4 weeks of injection compared to the control group. Conclusion: MSCs’ beneficial effects on ED was monitored with MR imaging, which might be a valuable tool for tracking and therapeutic monitoring in the future clinical study of stem cell therapy in ED.

Suppression of Cavernosal Fibrosis in a Rat Model.

Cavernosal fibrosis is an important pathologic condition leading to erectile dysfunction (ED). The etiologies of cavernosal fibrosis include aging, diabetes mellitus, castration, cavernosal nerve injury during radical prostatectomy, hypertension, and Peyronie disease. To summarize published studies investigating suppression of cavernosal fibrosis in rat models of ED of various etiologies. A literature search was conducted using PubMed. Relevant studies were identified using search terms such as erectile dysfunction, penis, fibrosis, and rat models. We reviewed representative literature studies on the mechanisms and suppression of cavernosal fibrosis in rat models of ED. The underlying mechanisms and potential therapeutic strategies suggested thus far for cavernosal fibrosis in rat models of ED were as follows. For age-related ED involving oxidative stress and tumor growth factor-β1 (TGF-β1)-driven pathways such as RhoA-ROCK1-LIMK2-cofilin or p42-44 and mitogen-activated protein kinase, proposed therapeutic strategies included phosphodiesterase type 5 inhibitors (PDE5Is), kallikrein-kinin system stimulators, and calorie restriction. For diabetes-related ED involving angiotensin-II- and TGF-β1-driven Smad and non-Smad pathways, TGF-β1-Wnt10b, and histone deacetylase (HDAC)-TGF-β1 pathways, positive therapeutic results were obtained with PDE5Is, TGF-β1 antagonists, HDAC inhibitors, antioxidants, sphingosine-1-phosphate receptor modulators (fingolimod), angiotensin-II antagonists, stem cell therapy, and antidiabetic drugs. For cavernosal nerve injury-associated ED involving TGF-β1-driven pathways (Smad or RhoA-ROCK1-LIMK2-cofilin), Sonic hedgehog signaling, angiotensin-II-Smad, and HDAC4-TGF-β1-Smad signaling triggered by cavernosal hypoxia, PDE5Is, angiotensin-II antagonists, stem cell therapy, HDAC inhibitors, Sonic hedgehog administration, ROCK inhibitors, and LIMK2 inhibitors have shown positive results. For testosterone deficiency-associated ED, TGF-β1-driven pathways were found to be responsive to testosterone supplementation. For hypertensive ED, positive therapeutic results were obtained with angiotensin-II antagonists. For Peyronie disease involving TGF-β1 or myostatin signaling, proposed therapeutic strategies included intra-tunical injection of TGF-β receptor inhibitors or adipose tissue-derived stem cells and HDAC2 small hairpin RNA. Several signaling pathways appear to be responsible for the development of cavernosal fibrosisrelated to ED of various etiologies. Some therapeutic success has been achieved in animal models, but further research focusing on mechanism-specific targeted therapies is needed. Cho MC, Song WH, Paick J-S. Suppression of Cavernosal Fibrosis in a Rat Model. Sex Med Rev 2018;6:572-582.

164 The Effects of Multiple Adipose-Derived Stem Cell Intracorporeal Injections on Erectile Dysfunction in a Rat Model of Cavernosal Nerve Injury

Nerve injury after radical prostatectomy leads to erectile dysfunction in over half of treated patients. Despite contemporary advancements, current therapies are inefficient. Recently, experiments utilizing stem cell therapy have shown promising outcomes. In this study, using a rat model of cavernosal nerve injury (CNI), we sought to discover the effect of intracorporal injection (IC) of adipose-derived stem cells (ADSC) on erectile function (EF). Sprague-Dawly rats were randomized into four groups of rats (n=8/group): 1) EXP-1 group in which the animals underwent laparotomy (Lap) with CNI and IC injection of ADSC at the time of surgery. 2) EXP-2 group in which the rats underwent Lap with CNI and IC injection of ADSC both at the time of surgery and three weeks post CNI. 3) Crush group underwent Lap with CNI, and 4) The Sham control group underwent Lap and immediate closure. Six weeks after CNI, all four groups received EF evaluation via cavernosal nerve stimulation at 2.5V, 5V, and 7.5V and measurement of the intracorporal pressure response. Penile and major pelvic ganglion tissue was harvested for immunohistochemical (IHC) analysis.

Role of Jun amino-terminal kinase (JNK) in apoptosis of cavernosal tissue during acute phase after cavernosal nerve injury.

The present study aimed to identify which mitogen-activated protein kinase (p38 or Jun amino-terminal kinase [JNK]) was involved in cavernosal apoptosis during the acute phase after cavernosal nerve crush injury (CNCI) in rats to ameliorate apoptosis of cavernosal tissue, such as smooth muscle (SM). A total of twenty 10-week-old male Sprague-Dawley rats were divided equally into two groups: sham surgery (S) and CNCI (I). The I group approximated the clinical situation of men undergoing radical prostatectomy using two 60-second compressions of both CNs with a microsurgical vascular clamp. At 2-week postinjury, erectile response was assessed using electrostimulation. Penile tissues were harvested for immunohistochemistry analysis of alpha-SM actin (α-SMA), western blot analysis, and double immunofluorescence analysis of α-SMA and phosphorylated p38 or JNK, as well as double immunofluorescent of TUNEL and phosphorylated p38 or JNK. At 2-week postinjury, the I group had a significantly lower intracavernous pressure (ICP)/mean arterial pressure (MAP) and a lower area under the curve (AUC)/MAP than the S group. The I group also exhibited decreased immunohistochemical staining of α-SMA, an increase in the number of SM cells positive for phosphorylated JNK, an increased number of apoptotic cells positive for phosphorylated JNK, and increased JNK phosphorylation compared with the S group. However, there was no significant difference in p38 phosphorylation expression or the number of SM cells positive for phosphorylated p38 between the two groups. In conclusion, our data suggest that JNK, not p38, is involved in cavernosal apoptosis during the acute phase after partial CN damage.

Pioglitazone Improves Pelvic Ganglion Neuronal Survival

Cavernosal nerve injury is a common complication after radical prostatectomy and causes erectile dysfunction (ED). Our recent publication established that pioglitazone (PGZ) improves cavernosal nerve function after crush injury in the rat model by both neural protection and neuroregeneration. This result is clinically significant for the many men who undergo treatment for localized prostate cancer. A better understanding of the effects of PGZ on pelvic ganglion neurons after cavernosal nerve injury is warranted. In this Research Highlight, we discuss the implications of our investigation from a molecular and clinical perspective.