Time-dependent progress of lower urinary tract dysfunction in streptozotocin-induced diabetic rats with or without low-dose insulin treatment.

Objectives: To examine time-dependent functional and structural changes of the lower urinary tract in streptozotocin-induced diabetic rats with or without low-dose insulin treatment and explore the pathophysiological characteristics of insulin therapy on lower urinary tract dysfunction (LUTD) caused by diabetes mellitus (DM). Methods: Female Sprague-Dawley rats were divided into five groups: normal control (NC) group, 4 weeks insulin-treated DM (4-DI) group, 4 weeks DM (4-DM) group, 8 weeks insulin-treated DM (8-DI) group and 8 weeks DM (8-DM) group. DM was initially induced by i.p. injection of streptozotocin (65 mg/kg), and then the DI groups received subcutaneous implantation of insulin pellets under the mid dorsal skin. Voiding behavior was evaluated in metabolic cages. The function of bladder and urethra in vivo were evaluated by simultaneous recordings of the cystometrogram and urethral perfusion pressure (UPP) under urethane anesthesia. The function of bladder and urethra in vitro were tested by organ bath techniques. The morphologic changes of the bladder and urethra were investigated using Hematoxylin-Eosin and Masson's staining. Results: Both 4-and 8-weeks diabetic rats have altered micturition patterns, including increased 12-h urine volume, urinary frequency/12 hours and voided volume. In-vivo urodynamics showed the EUS bursting activity duration is longer in 4-DM group and shorter in 8-DM group compared to NC group. UPP change in 8-DM were significantly lower than NC group. While none of these changes were found between DI and NC groups. Organ bath showed the response to Carbachol and EFS in bladder smooth muscle per tissue weights was decreased significantly in 4- and 8-weeks DM groups compared with insulin-treated DM or NC groups. In contrast, the contraction of urethral muscle and maximum urethral muscle contraction per gram of the tissue to EFS stimulation were significantly increased in 4- and 8-weeks DM groups. The thickness of bladder smooth muscle was time-dependently increased, but the thickness of the urethral muscle had no difference. Conclusions: DM-induced LUTD is characterized by time-dependent functional and structural remodeling in the bladder and urethra, which shows the hypertrophy of the bladder smooth muscle, reduced urethral smooth muscle relaxation and EUS dysfunction. Low-dose insulin can protect against diuresis-induced bladder over-distention, preserve urethral relaxation and protect EUS bursting activity, which would be helpful to study the slow-onset, time-dependent progress of DM-induced LUTD.

Urethral-sparing laparoscopic simple prostatectomy for the treatment of benign prostatic hyperplasia with asymptomatic urethral stricture after urethral stricture surgery.

OBJECTIVE: To evaluate the efficacy of urethral-sparing laparoscopic simple prostatectomy (US-LSP) for the treatment of large-volume (>80 ml) benign prostatic hyperplasia (BPH) with asymptomatic urethral stricture (urethral lumen > 16 Fr) after urethral stricture surgery. METHODS: We retrospectively analyzed clinical data of 39 large-volume BPH patients with asymptomatic urethral stricture after urethral stricture surgery who underwent US-LSP from January 2016 to October 2021. Postoperative follow-ups were scheduled at 1, 3, and 6 months. RESULTS: All patients affected by significant BPH-related lower urinary tract symptoms (LUTS) including 22 cases with asymptomatic anterior urethral stricture and 17 cases with asymptomatic posterior urethral stricture. Median operative time was 118 min (interquartile range [IQR]100-145). Median estimated blood loss was 224 ml (IQR: 190-255). 33 patients(84.6%) avoided continuous bladder irrigation. Postoperative complications occurred in 5 patients (12.8%), including 4 cases with Clavien-Dindo grade 1 and grade 2 and 1 case with grade 3a. During follow-up, US-LSP presented statistically significant improvements in LUTS compared to baseline (P < 0.05). A total of 25 patients had normal ejaculation preoperatively and 3 patients (12%) complained retrograde ejaculation postoperatively. Two patients (5.1%) reported stress urinary incontinence (SUI) and no patient reported aggravated urethral stricture during follow-up. CONCLUSIONS: US-LSP was safe and effective in treating large-volume BPH with asymptomatic urethral stricture after urethral stricture surgery. Meanwhile, US-LSP could reduce the risk of SUI in patients with asymptomatic posterior urethral stricture and maintain ejaculatory function in a high percentage of patients.

The potential involvement of MRP5 pump in urethral dysfunction in streptozotocin-induced diabetic rats.

PURPOSE: To examine the effects of i.v. administration of MK-571, a MRP4/5 pump inhibitor, on urethral function in the urethane-anesthetized rat, and the changes of urethral multidrug resistance protein 5 (MRP5) pump in streptozotocin (STZ)-induced diabetes mellitus (DM) rats. METHODS: Isovolumetric cystometry and urethral perfusion pressure (UPP) measurements were carried out in normal control (NC) group and 8week DM groups under urethane anesthesia. When stable rhythmic bladder contractions were showed, UPP parameters were recorded after successive administration of various dose of MK-571. Additionally, urethral cyclic guanosine monophosphate (cGMP) protein level was evaluated by ELISA, and changes of MRP5 pump and neurogenic nitric oxide synthase (nNOs) in the urethra were examined with immunohistochemical staining and Western blot analysis. RESULTS: In NC group, UPPnadir was significantly decreased but UPP change increased after administration of MK-571, while no significant differences in UPP parameters were observed in 8-week DM group. Furthermore, urethral MRP5 protein level was up-regulated, whereas urethral cGMP and nNOS protein levels were down-regulated in 8-week DM group. CONCLUSIONS: MK-571 could not restore NO-mediated urethral relaxation dysfunction in DM rats, which may be attributed to the up-regulation of urethral MRP5 pump, and thus decrease of intracellular cGMP concentration in the urethra. These novel results would be useful for a better understanding of DM-related lower urinary tract dysfunction LUT (LUTD). Also, they could be helpful to study the importance of MRP pumps in the control of urethral relaxation mechanisms under physiological and pathological states.

Therapies Based on Adipose-Derived Stem Cells for Lower Urinary Tract Dysfunction: A Narrative Review.

Lower urinary tract dysfunction often requires tissue repair or replacement to restore physiological functions. Current clinical treatments involving autologous tissues or synthetic materials inevitably bring in situ complications and immune rejection. Advances in therapies using stem cells offer new insights into treating lower urinary tract dysfunction. One of the most frequently used stem cell sources is adipose tissue because of its easy access, abundant source, low risk of severe complications, and lack of ethical issues. The regenerative capabilities of adipose-derived stem cells (ASCs) in vivo are primarily orchestrated by their paracrine activities, strong regenerative potential, multi-differentiation potential, and cell-matrix interactions. Moreover, biomaterial scaffolds conjugated with ASCs result in an extremely effective tissue engineering modality for replacing or repairing diseased or damaged tissues. Thus, ASC-based therapy holds promise as having a tremendous impact on reconstructive urology of the lower urinary tract.

Improvement of urethral dysfunction by 5-HT1A receptor agonist NLX-112 in diabetic rats.

OBJECTIVE: To examine the effects of the selective 5-HT1A receptor agonist, NLX-112, on urethral function in streptozotocin-induced diabetic rats. MATERIALS AND METHODS: Female Sprague-Dawley rats (n = 32) were divided into two groups: rats with type 1 diabetes mellitus (T1DM) and age-matched normal control rats (NC). T1DM was induced by intraperitoneal injection of streptozotocin (65 mg/kg). Isovolumetric cystometry and urethral perfusion pressure (UPP) were evaluated 10 weeks postinjection in rats (n = 9 per group). The selective 5-HT1A receptor antagonist, WAY-100635 maleate salt, was administered after NLX-112 hydrochloride dose-response curve was generated (intravenously). The remaining rats were used for immunofluorescence and Western blot assays. RESULTS: Compared to controls, type 1 diabetic rats (T1D rats) had lower maximal intravesical pressure (IP max) and UPP changes. In T1D rats, NLX-112 hydrochloride (0.003-1.0 mg/kg) induced dose-dependent decreases in UPP nadir, IP max, high-frequency oscillations (HFOs) rate; and increases in UPP change and HFOs amplitude. WAY-100635 maleate salt (0.3 mg/kg) partially or completely reversed the NLX-112-induced changes. Immunofluorescence revealed that 5-HT1A receptors were found in the L6-S1 spinal cord dorsolateral nucleus, but the expression was significantly higher in the T1D rats. Additionally, Western blot showed there were significantly more 5-HT1A receptors in the ventral L6-S1 spinal cord of T1D rats. CONCLUSIONS: Urethral dysfunction in T1D rats was improved by NLX-112. 5-HT1A receptors were upregulated in the dorsolateral nucleus of L6-S1 spinal cord in T1D rats. These findings suggest that NLX-112 may constitute a novel therapeutic strategy to treat diabetic urethral dysfunction.

The Design and Rationale of a Multicentre Randomised Controlled Trial Comparing Transperineal Percutaneous Laser Ablation With Transurethral Resection of the Prostate for Treating Benign Prostatic Hyperplasia.

Background: Transurethral resection of the prostate (TURP) is regarded as the "gold standard" for the treatment of benign prostatic hyperplasia (BPH) in elderly men. However, ~15% of patients who had undergone TURP had intraoperative and postoperative complications, such as bleeding, urinary incontinence and urethral stricture. Transperineal percutaneous laser ablation (TPLA) is a method that places the optical fibre directly into the prostate with the guidance of ultrasound imaging, and the percutaneous transperineal approach is performed distal to the urethra and rectum to protect these structures and reduce urethral or postoperative infection. Several studies on TPLA for BPH treatment have been reported recently; however, high-quality randomised controlled trial (RCT) to evaluate its efficacy, safety, and long-term follow up remain absent. Methods: This study is a multicentre, open-label RCT to assess the efficacy and safety of TPLA vs. TURP to treat BPH. We hypothesise that the TPLA has non-inferior efficacy to TURP in the International Prostate Symptom Score (IPSS) at 3 months changing from the baseline and lower incidence of post-surgery complications. One hundred and fourteen patients with BPH will be recruited at 19 sites and randomly assigned at 1:1 to TPLA or TURP groups. The patients will be followed up at 1, 3, 6, 12, and 24 months after the procedure. Discussion: The study will be the first multicentre clinical trial including 16 participating centres in China, Italy, Switzerland, and Poland with relatively large sample size 114. By comprehensively compare the safety and efficacy of TPLA with TURP in patients with BPH, especially concerning the improvement of lower urinary tract symptoms (LUTS) and complication incidence, the study will help to illustrate the clinical value of TPLA and provide a beneficial alternative treatment for BPH patients. Clinical Trial Registration: The study has been registered on Chinese Clinical Trial Registry (http://www.chictr.org.cn), identifier [ChiCTR1900022739].

Effects of low-dose insulin or a soluble guanylate cyclase activator on lower urinary tract dysfunction in streptozotocin-induced diabetic rats.

AIMS: To examine the effects of low-dose insulin or a soluble guanylate cyclase activator (sGC) on lower urinary tract dysfunction (LUTD) in rats with diabetes mellitus (DM). MAIN METHODS: Female Sprague-Dawley rats were divided into non-DM control (N), DM induced by streptozotocin (65 mg/kg), with low-dose insulin (DI), DM with vehicle (D), and DM with sGC (GC) groups. In GC group, BAY 60-2770 (1 mg/kg/day) was orally administered in 6-8 weeks after DM. Voiding assay at 2, 4, and 8 weeks after DM, cystometry, and urethral pressure recordings at 8 weeks of DM were performed. mRNA levels of NO-related markers and cGMP protein levels in the urethra, and ischemia and inflammation markers in the bladder were evaluated by RT-PCR. KEY FINDINGS: Moderate levels of high blood glucose were maintained in Group DI versus Group D. The 24-h voided volume was significantly higher in Group D versus Groups N and DI. Non-voiding contractions were significantly greater, and voiding efficiency and urethral pressure reduction were significantly lower in Group D versus Groups N, DI, and GC. Urethral cGMP levels were significantly lower in Group D versus Groups N and GC. mRNA levels of PDE5 in the urethra and ischemia and inflammation markers in the bladder increased in Group D versus Group N or DI was reduced after sGC treatment. SIGNIFICANCE: DI rats with a lesser degree of bladder and urethral dysfunction might be useful as a slow-progressive DM model. sGC activation could be an effective treatment of LUTD in DM.

Identification of a Risk Stratification Model to Predict Overall Survival and Surgical Benefit in Clear Cell Renal Cell Carcinoma With Distant Metastasis.

Background: Clear cell renal cell carcinoma (ccRCC) is the main subtype of renal cell carcinoma and has different prognoses, especially in patients with metastasis. Here, we aimed to establish a novel model to predict overall survival (OS) and surgical benefit of ccRCC patients with distant metastasis. Methods: Using data from the Surveillance, Epidemiology, and End Results (SEER) databases, we identified 2185 ccRCC patients with distant metastasis diagnosed from 2010 to 2015. Univariate and multivariate Cox analysis were used to identify significant prognostic clinicopathological variables. By integrating these variables, a prognostic nomogram was constructed and evaluated using C-indexes and calibration curves. The discriminative ability of the nomogram was measured by analyses of receiver operating characteristic (ROC) curve. A risk stratification model was built according to each patient's total scores. Kaplan-Meier curves were performed in the low-, intermediate- and high-risk groups to evaluate the survival benefit of surgery. Results: Eight clinicopathological variables were included as independent prognostic factors in the nomogram: grade, marital status, T stage, N stage, bone metastasis, brain metastasis, liver metastasis, and lung metastasis. The nomogram had a better discriminative ability for predicting OS than Tumor-Node-Metastasis (TNM) stage. The C-index was 0.71 (95% CI 0.68-0.74) in the training cohort. The calibration plots demonstrated that the nomogram-based predictive outcomes had good consistency with the actual prognosis results. Total nephrectomy improved prognosis in both the low-risk and intermediate-risk groups, but partial nephrectomy could only benefit the low-risk group. Conclusions: We constructed a predictive nomogram and risk stratification model to evaluate prognosis in ccRCC patients with distant metastasis, which was valuable for prognostic stratification and making therapeutic decisions.

Magnetic targeting of super-paramagnetic iron oxide nanoparticle labeled myogenic-induced adipose-derived stem cells in a rat model of stress urinary incontinence.

Cell-based injectable therapy utilizing stem cells is a promising approach for the treatment of stress urinary incontinence (SUI). Applying a magnetically controlled cell delivery approach has enormous potential to enhance cell retention capability within the specified site. To assess the therapeutic efficacy of cellular magnetic targeting, we applied an external magnetic force to target an adipose-derived stem cell based therapy in a rat model of SUI. The results revealed that magnetic attraction of transplanted cells under the magnetic field was generated by cell uptake of superparamagnetic iron oxide nanoparticles in vitro. More importantly, magnetic targeting improved the retention rate of transplanted cells and facilitated the restoration of sphincter structure and function in a rat SUI model according to the results of histological examination and urodynamic testing. Therefore, magnetically guided targeting strategy might be a potential therapy method for treatment of SUI.

A Lipid-Nanosphere-Small MyoD Activating RNA-Bladder Acellular Matrix Graft Scaffold [NP(saMyoD)/BAMG] Facilitates Rat Injured Bladder Muscle Repair and Regeneration [NP(saMyoD)/BAMG].

BACKGROUND: Bladder tissue engineering is an excellent alternative to conventional gastrointestinal bladder enlargement in the treatment of various acquired and congenital bladder abnormalities. We constructed a nanosphere-small MyoD activating RNA-bladder acellular matrix graft scaffold NP(saMyoD)/BAMG inoculated with adipose-derived stem cells (ADSC) to explore its effect on smooth muscle regeneration and bladder repair function in a rat augmentation model. METHODS: We performed many biotechniques, such as reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot, MTT assay, HE staining, masson staining, and immunohistochemistry in our study. Lipid nanospheres were transfected into rat ADSCs after encapsulate saRNA-MyoD as an introduction vector. Lipid nanospheres encapsulated with saRNA-MyoD were transfected into rat ADSCs. The functional transfected rat ADSCs were called ADSC-NP(saMyoD). Then, Rat models were divided into four groups: sham group, ADSC-BAMG group, ADSC-NP(saMyoD)/BAMG group, and ADSC-NP(saMyoD)/SF(VEGF)/BAMG group. Finally, we compared the bladder function of different models by detecting the bladder histology, bladder capacity, smooth muscle function in each group. RESULTS: RT-PCR and Western blot results showed that ADSCs transfected with NP(saMyoD) could induce high expression of α-SMA, SM22α, and Desmin. At the same time, MTT analysis showed that NP(saMyoD) did not affect the activity of ADSC cells, suggesting little toxicity. HE staining and immunohistochemistry indicated that the rat bladder repair effect (smooth muscle function, bladder capacities) was better in the ADSC-NP(saMyoD)/BAMG group, ADSC-NP(saMyoD)/SF(VEGF)/BAMG group than in the control group. CONCLUSIONS: Taken together, our results demonstrate that the NP(saMyoD)/SF(VEGF)/BAMG scaffold seeded with ADSCs could promote bladder morphological regeneration and improved bladder urinary function. This strategy of ADSC-NP(saMyoD)/SF(VEGF)/BAMG may has a potential to repair bladder defects in the future.

Urethral dysfunction and alterations of nitric oxide mechanisms in streptozotocin-induced diabetic rats with or without low-dose insulin treatment.

AIMS: To establish an animal model of diabetes mellitus (DM) with moderately elevated blood glucose levels, and to examine the nitric oxide (NO) mechanism controlling urethral function in streptozotocin (STZ)-induced DM rats. MAIN METHODS: Female Sprague-Dawley rats were used. DM was induced by intraperitoneal injection of STZ (65 mg/kg) and some of them received subcutaneous implantation of a low-dose insulin pellet. Voiding behavior was evaluated in metabolic cages. Isovolumetric cystometry and urethral perfusion pressure (UPP) were then evaluated under urethane anesthesia, during which L-arginine (100 mg/kg) and N-nitro-L-arginine methyl ester hydrochloride (L-NAME) (50 mg/kg) were administered intravenously. In vitro urethral activity was also tested by organ bath muscle strip studies. KEY FINDINGS: UPP changes and high-frequency oscillation (HFO) were significantly (P < 0.05) smaller in 8-weeks DM rats vs. normal control (NC) rats or insulin-treated DM rats, which showed reductions in urine overproduction and voided volume per micturition vs. untreated DM rats. UPP nadir was decreased by L-arginine in NC and insulin-treated DM groups, and decreased by L-NAME in all groups. Five of 6 untreated DM rats showed a detrusor-sphincter dyssynergia pattern after L-NAME. In in vitro studies, the relative ratio of L-NAME-induced reductions of urethral relaxation against pre-drug urethral relaxation was significantly smaller in DM vs. NC rats (P < 0.05). SIGNIFICANCE: Low-dose insulin-treated DM rats would be a useful model for studying natural progression of DM-induced lower urinary tract dysfunction. The impaired NO-mediated urethral relaxation mechanisms play an important role in DM-induced urethral dysfunction, which could contribute to DM-induced inefficient voiding.

The Fabrication and Evaluation of a Potential Biomaterial Produced with Stem Cell Sheet Technology for Future Regenerative Medicine.

To date, the decellularized scaffold has been widely explored as a source of biological scaffolds for regenerative medicine. However, the acellular matrix derived from natural tissues and organs has a lot of defects, including the limited amount of autogenous tissue and surgical complication such as risk of blood loss, wound infection, pain, shock, and functional damage in the donor part of the body. In this study, we prepared acellular matrix using adipose-derived stem cell (ADSC) sheets and evaluate the cellular compatibility and immunoreactivity. The ADSC sheets were fabricated and subsequently decellularized using repeated freeze-thaw, Triton X-100 and SDS decellularization. Oral mucosal epithelial cells were seeded onto the decellularized ADSC sheets to evaluate the cell replantation ability, and silk fibroin was used as the control. Then, acellular matrix was transplanted onto subcutaneous tissue for 1 week or 3 weeks; H&E staining and immunohistochemical analysis of CD68 expression and quantitative real-time PCR (qPCR) were performed to evaluate the immunogenicity and biocompatibility. The ADSC sheet-derived ECM scaffolds preserved the three-dimensional architecture of ECM and retained the cytokines by Triton X-100 decellularization protocols. Compared with silk fibroin in vitro, the oral mucosal epithelial cells survived better on the decellularized ADSC sheets with an intact and consecutive epidermal cellular layer. Compared with porcine small intestinal submucosa (SIS) in vivo, the homogeneous decellularized ADSC sheets had less monocyte-macrophage infiltrating in vivo implantation. During 3 weeks after transplantation, the mRNA expression of cytokines, such as IL-4/IL-10, was obviously higher in decellularized ADSC sheets than that of porcine SIS. A Triton X-100 method can achieve effective cell removal, retain major ECM components, and preserve the ultrastructure of ADSC sheets. The decellularized ADSC sheets possess good recellularization capacity and excellent biocompatibility. This study demonstrated the potential suitability of utilizing acellular matrix from ADSC sheets for soft tissue regeneration and repair.

Urethral dysfunction in a rat model of chemically induced prostatic inflammation: potential involvement of the MRP5 pump.

Prostate inflammation (PI) is a clinical condition associated with infection and/or inflammation of the prostate. It is a common disease frequently associated to lower urinary tract (LUT) symptoms. The urethra is an understudied structure in the LUT and plays a fundamental role in the urinary cycle. Here, we proposed to evaluate the effect of PI on the urethra tissue. Male Sprague-Dawley rats were used, and PI was induced by formalin injection into the ventral lobes of the prostate. The pelvic urethra at the prostatic level was harvested for histological analysis, contraction (electrical field stimulation and phenylephrine), and relaxation (sodium nitroprusside/MK-571) experiments. Various gene targets [cytochrome c oxidase subunit 2, transforming growth factor-ß1, interleukin-1ß, hypoxia-inducible factor-1α, α1A-adrenoceptor, inositol 1,4,5-trisphosphate receptor type 1, voltage-gated Ca2+ channel subunit-α1D, neuronal nitric oxide synthase, soluble guanylyl cyclase, phosphodiesterase 5A, protein kinase CGMP-dependent 1, and multidrug resistance-associated protein 5 (MRP5; ATP-binding cassette subfamily C member 5)] were quantified, and cGMP levels were measured. No histological changes were detected, and functional assays revealed decreased contraction and increased relaxation of urethras from the PI group. The addition of MK-571 to functional assays increased urethral relaxation. Genes associated with inflammation were upregulated in urethras from the PI group, such as cytochrome oxidase c subunit 2, transforming growth factor-ß1, interleukin-1ß, and hypoxia-inducible factor-1α. We also found increased expression of L-type Ca2+ channels and the neuronal nitric oxide synthase enzyme and decreased expression of the MRP5 pump. Finally, cGMP production was enhanced in urethral tissue of PI animals. The results indicate that PI is associated with proinflammatory gene expression in the urethra without histologically evident inflammation and that PI produces a dysfunctional urethra and MRP5 pump downregulation, which results in cGMP accumulation inside the cell. These findings would help to better understand LUT dysfunctions associated with PI and the role of MRP pumps in the control of LUT function.

Time-Dependent Changes of Urethral Function in Diabetes Mellitus: A Review.

This article reviewed the current knowledge on time-course manifestation of diabetic urethral dysfunction (DUD), and explored an early intervention target to prevent the contribution of DUD to the progression of diabetes-induced impairment of the lower urinary tract (LUT). In the literature search through PubMed, key words used included "diabetes mellitus," "diabetic urethral dysfunction," and "diabetic urethropathy." Polyuria and hyperglycemia induced by diabetes mellitus (DM) can cause the time-dependent changes in functional and morphological manifestations of DUD. In the early stage, it promotes urethral dysfunction characterized by increased urethral pressure during micturition. However, the detrusor muscle of the bladder tries to compensate for inducing complete voiding by increasing the duration and amplitude of bladder contractions. As the disease progresses, it can induce an impairment of coordinated micturition due to dyssynergic activity of external urethra sphincter, leading to detrusor-sphincter dyssynergia. The impairment of relaxation mechanisms of urethral smooth muscles (USMs) may additionally be attributable to decreased responsiveness to nitric oxide, as well as increased USM responsiveness to α1-adrenergic receptor stimulation. In the late stage, diabetic neuropathy may play an important role in inducing LUT dysfunction, showing that the decompensation of the bladder and urethra, which can cause the decrease of voiding efficiency and the reduced thickness of the urothelium and the atrophy of striated muscle bundles, possibly leading to the vicious cycle of the LUT dysfunction. Further studies to increase our understandings of the functional and molecular mechanisms of DUD are warranted to explore potential targets for therapeutic intervention of DM-induced LUT dysfunction.

Streptozotocin-induced diabetes causes upregulation of serotonin (5-HT)2A/C receptors in lumbosacral cord motoneurons and down regulation of serotonergic paraneurons in the urethra.

Lower urinary tract (LUT) dysfunction is the most common complication of diabetes mellitus (DM). An involvement of the 5-HT2A receptor in spinal micturition control has been demonstrated in urethane anaesthetized DM rats in which i.v. administration of the 5-HT2A/2C receptor agonist 2,5-methoxy-4-iodoamphetamine (DOI), stimulated high frequency oscillations (HFOs) and improved micturition. However, the mechanisms involved in these effects are not completely understood. The present work showed that 5-HT2A and -2C receptors were upregulated in lumbosacral cord motoneurons, and the number of serotonergic paraneurons were downregulated in the urethra in DM group. The importance of the downregulation of urethral paraneurons in DM remains to be elucidated but may be related to the reduced urethral sensation caused by the disease. We suggest that targets of 5-HT receptor agonists for improvement of voiding function may be found both in the LUT and lumbosacral spinal cord.

The serotonin (5-hydroxytryptamine) 5-HT7 receptor is up-regulated in Onuf's nucleus in rats with chronic spinal cord injury.

OBJECTIVES: To examine the effect of intrathecal (i.t.) serotonin (5-hydroxytryptamine) 5-HT7 agonist administration on voiding function in the urethane-anesthetised rat, and the change in 5-HT7 receptor (5-HT7 R) expression in the lumbosacral cord Onuf's nucleus after spinal cord injury (SCI). MATERIALS AND METHODS: In all, 32 female Sprague-Dawley (SD) rats were equally divided into a spinally intact (SI) group and SCI group (n = 16 each). At 8 weeks after transection, half of the rats underwent continuous cystometry under urethane anaesthesia, and the 5-HT7 R-selective agonist LP44 was given (i.t.). The remaining rats were used for pseudorabies (PRV) retrograde tracing, immunofluorescence, and Western Blot. RESULTS: LP44 administered i.t. had no effect in the SI rats. In SCI rats, LP44 (1-30 µg/kg) induced significant dose-dependent increases in micturition volume, voiding efficiency, number of high-frequency oscillations per micturition; and decreases in residual volume, bladder capacity, peak bladder pressure, threshold pressure and non-voiding contractions. The 5-HT7 R antagonist, SB-269970 (10 µg/kg), partially reversed LP44-induced changes. Using PRV retrograde tracing and immunofluorescence, 5-HT7 Rs were found in the L6-S1 spinal cord Onuf's nucleus in both SI and SCI rats, but the expression was significantly greater in the SCI rats. Western blot showed significantly more 5-HT7 Rs in the ventral L6-S1 spinal cord in SCI rats. CONCLUSION: A 5-HT7 R agonist, given i.t., improved voiding efficiency in urethane-anesthetised SCI rats, and the 5-HT7 R was significantly up-regulated in the lumbosacral cord Onuf's nucleus. If valid for humans, these findings suggest that the 5-HT7 R could be a target for therapeutic interventions.

Angiogenesis Potential of Bladder Acellular Matrix Hydrogel by Compounding Endothelial Cells.

Rapid vascularization is very important in tissue engineering. Bladder acellular matrix (BAM) with inherent bioactive factors, a natural extracellular matrix (ECM) derived biomaterial, has been widely used as a scaffold to facilitate the repair and reconstruction of urinary tissues. However, the application of the traditional BAM scaffold has been limited due to the dense structure. To investigate the angiogenic potential of BAM, BAM hydrogels with tailored porous structures were prepared in this study by tuning BAM concentrations (4, 6, and 8 mg/mL). The 6 mg/mL BAM hydrogel was loaded with porcine iliac endothelial cells (PIECs), and their angiogenic potential was analyzed in vitro and in vivo. The mechanical strength and gelation speed of the BAM hydrogels increased, while their pore size decreased as concentration increased. Commercially available collagen hydrogel (2.5 mg/mL) showed weaker mechanical properties than BAM hydrogels but similar gelation speed and pore size as 6 mg/mL BAM hydrogel. To ensure a similar three-dimensional microenvironment for the PIECs, 6 mg/mL BAM and collagen hydrogels were selected for the in vitro and in vivo experiments. A significantly higher density of viable, fusiform PIECs of average length ∼50 µm was observed in the BAM hydrogel, while those inside the collagen hydrogel were spherical and ∼30 µm long. In addition, the PIECs/BAM hydrogel resulted in significantly higher revascularization compared with the PIECs/collagen and unloaded BAM hydrogels. The higher angiogenic potential of the PIECs/BAM hydrogel is due to the growth factors that promote PIEC proliferation and therefore vascularization.

Prevascularized bladder acellular matrix hydrogel/silk fibroin composite scaffolds promote the regeneration of urethra in a rabbit model.

OBJECTIVE: To evaluate the effects of urethral regeneration with prevascularized bladder acellular matrix hydrogel (BAMH)/silk fibroin (SF) composite scaffolds in a rabbit model. MATERIALS AND METHODS: BAMH/SF and collagen Type I hydrogel/SF (CH/SF) scaffolds were prepared and the structure of the scaffolds was assessed using scanning electron microscopy. BAMH/SF, CH/SF and SF scaffolds were incubated in the omentum of male rabbits for two weeks and then harvested for repairing autologous urethral defects. Histological analysis of the incubated scaffolds was performed to evaluate the neovascularization capacity, and the outcomes of urethroplasty were evaluated at one and three months post-operatively. RESULTS: The composited scaffolds were composed of a highly porous BAMH or CH buttressed by compact SF outer layer. The histological analysis of the incubated BAMH/SF revealed a signifcant increase of the neovascularization among three groups after a two-week incubation. At three months, the urethra maintained wide caliber in the BAMH/SF group. Strictures were found in the CH/SF and SF groups. Histologically, at one month, intact and multilayer epithelium occurred in the BAMH/SF group, and one layer epithelium was found in the CH/SF and SF groups. However, there was similar epithelial regeneration in BAMH/SF and CH/SF groups at three months (p > 0.05). Comparisons of smooth muscle content and vessel density among the SF, CH/SF and BAMH/SF revealed a significant increase at each time point (p < 0.05). CONCLUSION: Our results demonstrate that incubated BAMH/SF promote neovascularization, and prevascularized BAMH/SF promote the regeneration of the urethral epithelium and smooth muscle, which indicates its potential for urethral reconstruction.

Effect of 5-HT2A receptor antagonist ketanserin on micturition in male rats.

OBJECTIVES: This study aimed to investigate the effects of ketanserin on micturition mediated via the 5-HT2A receptor in the motoneuron nucleus of the Lumbosacral cord, as reflected in high frequency oscillations (HFOs) of intravesical pressure and the external urethral sphincter electromyogram (EUS-EMG) in anesthetized male rats. METHODS：: Male Sprague-Dawley rats were used. Cystometry and EUS-EMG were performed in all rats under urethane anesthesia to examine the variations after successive intrathecal (i.t.) administration of various doses of ketanserin into the lumbosacral cord. Immunofluorescence staining and Western blotting were made to observe the distribution of 5-HT2 A and -2C receptors in the lumbosacral cord motor neurons. RESULTS: Compared to the controls, ketanserin-treated rats showed a declined trend of dose-dependent manner in the HFOs, in accordance with the variation of EUS-EMG, while decreased micturition volume, voiding efficiency, and increased post-void residual volume was only observed at the dose of 0.1 mg/kg. The effects of ketanserin on the HFO and EUS-EMG activity were partially or completely reversed by the 5-HT2A/2C receptor agonist, DOI. Meanwhile, immunofluorescence staining and Western blot analysis showed that immunoreactivity of 5-HT2A receptor was higher than that of 5-HT2C, labeling in the lumbosacral cord motoneurons. CONCLUSIONS: The intrathecally administrated 5-HT2A receptor antagonist ketanserin can weaken the EUS bursting activity, decrease HFOs, and reduce voiding efficiency as dose dependently. The effects of ketanserin on micturition may be mainly mediated via the 5-HT2A receptors in the motoneuron nucleus of the lumbosacral cord.