Synergistic effect of vaginal trauma and ovariectomy in a murine model of stress urinary incontinence: upregulation of urethral nitric oxide synthases and estrogen receptors

Molecular Processes in Stress Urinary Incontinence: A Systematic Review of Human and Animal Studies

Stress urinary incontinence (SUI) is a common and burdensome condition. Because of the large knowledge gap around the molecular processes involved in its pathophysiology, the aim of this review was to provide a systematic overview of genetic variants, gene and protein expression changes related to SUI in human and animal studies. On 5 January 2021, a systematic search was performed in Pubmed, Embase, Web of Science, and the Cochrane library. The screening process and quality assessment were performed in duplicate, using predefined inclusion criteria and different quality assessment tools for human and animal studies respectively. The extracted data were grouped in themes per outcome measure, according to their functions in cellular processes, and synthesized in a narrative review. Finally, 107 studies were included, of which 35 used animal models (rats and mice). Resulting from the most examined processes, the evidence suggests that SUI is associated with altered extracellular matrix metabolism, estrogen receptors, oxidative stress, apoptosis, inflammation, neurodegenerative processes, and muscle cell differentiation and contractility. Due to heterogeneity in the studies (e.g., in examined tissues), the precise contribution of the associated genes and proteins in relation to SUI pathophysiology remained unclear. Future research should focus on possible contributors to these alterations.

Urethral injection of dedifferentiated fat cells ameliorates sphincter damage and voiding dysfunction in a rat model of persistence stress urinary incontinence

Purpose

Dedifferentiated fat (DFAT) cells are mature adipocyte-derived multipotent cells that can be applicable to cell-based therapy for stress urinary incontinence (SUI). This study developed a persistence SUI model that allows long-term evaluation using a combination of vaginal distention (VD) and bilateral ovariectomy (OVX) in rats. Then, the therapeutic effects of DFAT cell transplantation in the persistence SUI model was examined.

Methods

In total, 48 Sprague–Dawley rats were divided into four groups and underwent VD (VD group), bilateral OVX (OVX group), VD and bilateral OVX (VD + OVX group), or sham operation (Control group). At 2, 4, and 6 weeks after injury, leak point pressure (LPP) and histological changes of the urethral sphincter were evaluated. Next, 14 rats undergoing VD and bilateral OVX were divided into two groups and administered urethral injection of DFAT cells (DFAT group) or fibroblasts (Fibroblast group). At 6 weeks after the injection, LPP and histology of the urethral sphincter were evaluated.

Results

The VD + OVX group retained a decrease in LPP with sphincter muscle atrophy at least until 6 weeks after injury. The LPP and urethral sphincter muscle atrophy in the DFAT group recovered better than those in the fibroblast group.

Conclusions

The persistence SUI model was created by a combination of VD and bilateral OVX in rats. Urethral injection of DFAT cells inhibited sphincter muscle atrophy and improved LPP in the persistence SUI model. These findings suggest that the DFAT cells may be an attractive cell source for cell-based therapy to treat SUI.

Review of Animal Models to Study Urinary Bladder Function

Simple Summary

The treatment of urinary bladder dysfunction requires the knowledge of bladder function, which involves physiology, pathology, and even psychology. Several animal models are available to study a variety of bladder disorders. These models include animals from rodents, such as mice and rats, to nonhuman primates, such as rabbits, felines, canines, pigs, and mini pigs. This review adapted animal models to study bladder function according to facility, priority, and disease.

Abstract

The urinary bladder (UB) serves as a storage and elimination organ for urine. UB dysfunction can cause multiple symptoms of failure to store urine or empty the bladder, e.g., incontinence, frequent urination, and urinary retention. Treatment of these symptoms requires knowledge on bladder function, which involves physiology, pathology, and even psychology. There is no ideal animal model for the study of UB function to understand and treat associated disorders, as the complexity in humans differs from that of other species. However, several animal models are available to study a variety of other bladder disorders. Such models include animals from rodents to nonhuman primates, such as mice, rats, rabbits, felines, canines, pigs, and mini pigs. For incontinence, vaginal distention might mimic birth trauma and can be measured based on leak point pressure. Using peripheral and central models, inflammation, bladder outlet obstruction, and genetic models facilitated the study of overactive bladder. However, the larger the animal model, the more difficult the study is, due to the associated animal ethics issues, laboratory facility, and budget. This review aims at facilitating adapted animal models to study bladder function according to facility, priority, and disease.

Estrogen deficiency affects tooth formation and gene expression in the odontogenic region of female rats

BACKGROUND

There is some evidence that estrogen regulates the expression of several genes in different cells, including dental cells. Therefore, the aim of this study was to investigate the role of estrogen deficiency during tooth development regarding tooth structure morphology and its impact on the expression of odontogenesis-related genes.

METHODS

A total of 40 female Wistar rats was divided into OVX (estrogen deficiency) and Sham (control) groups. Bilateral ovariectomy was performed in the OVX group, while Sham surgery was performed in the control group at the age of 21 days. At an age of 56 days, 16 rats were euthanized for gene expression analyses of Bmp4, Smad6, Tgfb1 and Runx2. At the age of 63 days, the remaining rats were euthanized for histological and morphometric analyses of teeth. The mandibles of the rats were submitted to μCT analysis. Tooth structures (enamel, dentin and dental pulp) were analyzed. T test was used to compare the mean differences between groups (p<0.05).

RESULTS

In the μCT analysis, enamel and dentin thickness were significantly increased in the control group (p<0.0001). Pulp dimensions were significantly larger in the OVX group (p<0.0001). A reduction of tooth structures in the OVX group was confirmed in HE staining. Smad6 was differentially expressed in the OVX group (p=0.04).

CONCLUSION

Estrogen deficiency affects gene expression in the odontogenic region and tooth structure morphology.

Managing urinary incontinence in women - a review of new and emerging pharmacotherapy

INTRODUCTION

The pharmacological treatment of urinary incontinence and overactive bladder (OAB) has been, for a longer time, based on antimuscarinic agents. In recent years, two other pharmacological principles have been introduced for the treatment of OAB and urgency urinary incontinence: the β3-adrenergic agent mirabegron and botulinum neurotoxin. Meanwhile, there is lack of effective drugs for the treatment of stress incontinence.

AREAS COVERED

This literature review presents synthetic compounds aimed to treat female urinary incontinence that are in phase II-III clinical development.

EXPERT OPINION

Antimuscarinic agents will continue to represent the current gold standard for the first-line pharmacological management of OAB and urgency urinary incontinence. The class of β3-agonists will certainly expand with the discovery and clinical development of novel agents. Combination therapy of antimuscarinic agents and β3-agonists could offer an alternative treatment in these patients, including those with symptoms refractory to first-line monotherapy. A huge number of preclinical studies are underway in this field exploring the therapeutic potential of many novel compounds while some have advanced to clinical phases of development.

A promising protein responsible for overactive bladder in ovariectomized mice

OBJECTIVE

Ovariectomy (OVX) in mice is a model mimicking a neuro-electronic proof of an overactive bladder in postmenopausal women. Overactive bladder (OAB) was recently found to be due to an altered gap junction protein in a rat model. Thus, this study was conducted to evaluate changes in cell junction protein expression and composition in the bladder of OVX mice.

MATERIALS AND METHODS

Thirty-six virgin female mice were randomized into three groups: mice with a sham operation only (control), OVX mice without estradiol (E2) replacement, and OVX mice with E2 replacement (OVX + E2). Cystometry assessment was conducted and cell junction-associated protein zonula occludens-2 (ZO-2) expression was measured after 8 weeks. Voiding interval values (time between voids) were assessed in mice under anesthesia. After measurements, the bladders were removed for proteomic analysis using the label-free quantitative proteomics and liquid chromatography-mass spectrometry technology. Lastly, immunohistochemistry (IHC) and Western blot were used to confirm the location and level, respectively, of ZO-2 expression.

RESULTS

We identified 73 differentially expressed proteins in the bladder of OVX mice. The OVX mice showed significantly lower voiding interval values. Voiding interval values were significantly higher in the OVX + E2 group than in the OVX group. Urothelial thicknesses in the bladder were also significantly lower in the OVX group than in the control group. E2 replacement reversed the urothelium layers. Additionally, the expression of ZO-2, a tight junction protein, was the most affected by OVX treatment. IHC and Western blot confirmed the downregulation of ZO-2 in the bladder of OVX mice. Expression of ZO-2 protein was significantly increased in OVX + E2 group compared with OVX group.

CONCLUSION

This exploratory study estimated changes in protein expression and composition in the bladder of OVX mice. These changes may be associated with the molecular mechanisms of OAB.

Potential therapeutic role of punicalagin against mechanical-trauma-induced stress urinary incontinence via upregulation of Nrf2 and TGF-β1 signaling : Effect of punicalagin on mechanical trauma induced SUI

INTRODUCTION AND HYPOTHESIS

We investigated the effect of punicalagin (PUN; 2,3-hexahydroxydiphenoyl-gallagyl-D-glucose), on mechanical-trauma-induced stress urinary incontinence (SUI) in mouse and the mechanisms underlying any effects.

METHODS

Ninety virgin female C57BL/6 mice were randomized into six groups: five groups underwent vaginal distention (VD) for 1 h and leak-point pressure (LPP) was measured on the 1st, 3rd, 7th, 14th, and 28th day following (VD groups 1 d, 3 d, 7 d, 14 d, and 28 d). The sixth group was a noninstrumented control (NC) group. Then, 75 virgin female C57BL/6 mice were randomized into five groups: a VD group (that just underwent VD) and an NC group were orally administered saline every day for 7 days; and three VD + PUN groups that underwent VD and were orally administered PUN respectively at 2.5, 5, and 10 mg/kg every day for 7 days. LPP was tested on the day 7, then all mice were sacrificed and their urethras and anterior vaginal walls harvested for Masson staining, immunohistochemistry study, Western blot analysis, and quantitative polymerase chain reaction (qPCR).

RESULTS

LPPs after VD were significantly lower than the NC group, and the LPPs of mice on days 14 and 28 day after VD were significantly higher than on the days 1, 3, and 7. PUN significantly improved VD-induced drops in LPP and alleviated VD-induced decrease of collagen I, collagen III, α-smooth muscle actin (SMA), transforming growth factor (TGF)-β1, and p-Smad3, nuclear factor-erythroid 2 p45-related factor 2 (Nrf2), and glutathione peroxidase (GPx1) protein levels, and increase of 8-hydroxydeoxyguanosine (OHdG) in urethra and anterior vaginal wall. PUN also up-regulated the expression of manganese superoxide dismutase (MnSOD), whereas protein levels of Smad 2, p-Smad2, and Smad3 were not changed.

CONCLUSIONS

PUN exerts certain therapeutic effect on mechanical-trauma-induced SUI in mice, which might be through the activation of TGF-β1/Smad3 and Nrf2/antioxidant response element (ARE) signaling activation.