Pathology of urethral fibromuscular system related to parturition-induced stress urinary incontinence and TGF-β1/Smad pathway

Pirfenidone improves voiding function by suppressing bladder fibrosis in underactive bladder rats

Underactive bladder (UAB), characterized by a complex set of symptoms with few treatment options, can significantly reduce the quality of life of affected people. UAB is characterized by hyperplasia and fibrosis of the bladder wall as well as decreased bladder compliance. Pirfenidone is a powerful anti-fibrotic agent that inhibits the progression of fibrosis in people with idiopathic pulmonary fibrosis. In the current study, we evaluated the efficacy of pirfenidone in the treatment of bladder fibrosis in a UAB rat model. UAB was induced by crushing damage to nerve bundles in the major pelvic ganglion. Forty-two days after surgery, 1 mL distilled water containing pirfenidone (100, 300, or 500 mg/kg) was orally administered once every 2 days for a total of 10 times for 20 days to the rats in the pirfenidone-treated groups. Crushing damage to the nerve bundles caused voiding dysfunction, resulting in increased bladder weight and the level of fibrous related factors in the bladder, leading to UAB symptoms. Pirfenidone treatment improved urinary function, increased bladder weight and suppressed the expression of fibrosis factors. The results of this experiment suggest that pirfenidone can be used to ameliorate difficult-to-treat urological conditions such as bladder fibrosis. Therefore, pirfenidone treatment can be considered an option to improve voiding function in patient with incurable UAB.

The role of Gestational Diabetes Mellitus and pelvic floor 3D-ultrasound assessment during pregnancy predicting urinary incontinence: a prospective cohort study

Postpartum urinary incontinence may have a severe impact on women's health. Despite pregnancy and parturition being the most recognized risk factors, methods to identify new pregnant predictor risk factors are needed. Our study investigated the Gestational Diabetes Mellitus, clinical and pelvic floor 3D-ultrasound markers in pregnant women as predictors for 6-18 months of urinary incontinence. This prospective cohort study included nulliparous pregnant women submitted to Gestational Diabetes Mellitus screening in the second trimester. Pelvic floor 3D Ultrasound was performed at the second and third trimesters of gestation to evaluate the pelvic floor muscles and functions. Clinical data, the ICIQ-SF, and ISI questionnaires for urinary incontinence were applied in the third trimester and 6-18 months postpartum. Univariate analysis (P < .20) to extract risk factors variables and multivariate logistic regression analysis (P < .05) to obtain the adjusted relative ratio for urinary incontinence were performed. A total of 93 participants concluded the follow-up. Using the variables obtained by univariate analysis and after adjustments for potential confounders, multivariate analysis revealed that Gestational Diabetes Mellitus exposure was a solid and independent risk factor for 6-18 months of urinary incontinence (Adjusted RR 8.08; 95%CI 1.17-55.87; P:0.034). In addition, a higher Hiatal area observed in distension maneuver from the second to third trimester was negatively associated (Adjusted RR 0.96; 95%CI 0.93-0.99; P:0.023). In conclusion, Gestational Diabetes Mellitus was positively associated with 6-18 months of urinary incontinence, and higher Hiatal area distension was negatively associated.

Advances in the molecular pathogenesis and cell therapy of stress urinary incontinence

Stress urinary incontinence (SUI) is very common in women. It affects patients' mental and physical health, and imposed huge socioeconomic pressure. The therapeutic effect of conservative treatment is limited, and depends heavily on patient persistence and compliance. Surgical treatment often brings procedure-related adverse complications and higher costs for patients. Therefore, it is necessary to better understand the potential molecular mechanisms underlying stress urinary incontinence and develop new treatment methods. Although some progress has been made in the basic research in recent years, the specific molecular pathogenic mechanisms of SUI are still unclear. Here, we reviewed the published studies on the molecular mechanisms associated with nerves, urethral muscles, periurethral connective tissue and hormones in the pathogenesis of SUI. In addition, we provide an update on the recent progresses in research on the use of cell therapy for treating SUI, including research on stem cells therapy, exosome differentiation and gene regulation.

Establishment of Rat Model of Female Genital Sexual Arousal Disorder

Introduction

Female Genital Sexual Arousal Disorder (FGSAD) seriously affects women's quality of life and Sexual life, but it still lacks ideal FGSAD animal models for further study.

Aim

To establish a specific model of female genital sexual arousal disorder and explore the mechanisms resulting in FGSAD.

Methods

After delivery, female rats were guided by expansions of the vagina and ovariectomy (VD+OVX, n = 10); in VD group female rats were just extended by the vagina (VD, n = 10), in OVX group female rats were treated with ovariectomy (OVX, n = 10);the remaining had 1 longitudinal incision as sham group(n = 10).

Outcomes

Vaginal dilatation combined with ovariectomy in rats may reflect female genital sexual arousal disorder with high reproducibility and stability.

Results

Vaginal tissue of female rats in OVX group and VD+OVX group showed an increase in blood flow, decrease in muscle content compared to the sham group. The proportion of collagen fiber I/III decreased and the elastic fiber showed significant rupture and fragmentation; Structural reticular integrity was also significantly separated and broken from the muscle fibers. However, there was no significant difference in vaginal blood flow, fibers and vascular between VD group and Sham group. The damage of vaginal tissue in VD+OVX group was more significant than that in OVX and VD groups.

Clinical Translation

We have constructed a specific animal model that can provide clinical insights into the mechanism of FGSAD and serves as a good avenue for further research of its treatment.

Strengths and Limitations

Vaginal dilatation combined with ovariectomy in rats is a specific animal model with high reproducibility and stability, but we do acknowledge the shortcomings and limitation present in our study. Since genital arousal disorder has many different etiologies that impact the vagina, the clitoris and surrounding tissues, there is no “gold standard” model that different models attempt to investigate different etiologies.

Conclusion

The female genital sexual arousal disorder model established by vaginal dilatation combined with ovariectomy is a novel rat model with simple induction conditions, which pathogenic mechanism of female genital sexual arousal disorders maybe connected with the change of VEGF and MMP-9 in vaginal fibromuscular system and microvascular.

Li G, Yu P, Hu Y, et al. Establishment of Rat Model of Female Genital Sexual Arousal Disorder. Sex Med 2022;10:100530.

Stress urinary incontinence and the forgotten female hormones

The use of hormones to treat stress urinary incontinence (SUI) has fallen out of favor because of concerns over safety following publication of the Women's Health Initiative study. In addition, there are data that suggest that estrogen treatment does not help SUI. As women age, the decline in androgen output mirrors the increasing prevalence of SUI implying a potential causal association. Therefore, we suggest that androgens are the 'forgotten female hormone.' Vaginal estrogens can treat pelvic floor structures without significant systemic effects; we suggest that vaginal androgens can act similarly and thereby avoid the unwanted systemic effects of androgenization in women. Based on available preclinical and clinical data, we suggest that research should investigate vaginal treatment with androgen hormones as adjunctive therapy to pelvic floor exercises for SUI. In a postmenopausal woman, this could be supplemented with estrogens if trial data warrant it.

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.

SMAD2, SMAD3 and TGF-β GENE expressions in women suffering from urge urinary incontinence and pelvic organ prolapse

We evaluated the changes in the levels of TGF-β and SMAD gene and protein expression in the uterosacral ligament (USL) of patients with concomitant pelvic organ prolapse (POP) and urgency urinary incontinence (UUI) to illuminate the pathophysiology of UUI. The TGF-β pathway is involved in collagen synthesis and degradation. The Transforming Growth Family-β (TGF-β) superfamily has essential intracellular signaling components, such as newly identified SMAD family members. We evaluated the changes in the levels of TGF-β and SMAD gene and protein expression in the USL of patients with concomitant pelvic organ prolapse (POP) and UUI. This study included 10 patients who had been diagnosed with POP and UUI in the study group and 14 asymptomatic women without complaints of POP and UUI in the control group. Biopsy samples were collected from bilateral USL tissues during vaginal or abdominal hysterectomy. Total RNA was extracted from USL tissue and analyzed by qPCR. The protein expression levels were also analyzed with ELISA. In UUI patients, SMAD3 and TGF-ß1 gene expression levels significantly decreased compared to the control patients (p = 0.008 and p = 0.006, respectively). SMAD2 mRNA levels did not differ between the study and control groups (p = 0.139). No differences was found in the levels of SMAD2, SMAD3, and TGF-ß1 protein expression between the two groups. The reduction in the gene and protein expression levels of SMAD3 and TGF-ß1 in women with UUI and lax uterosacral ligaments may indicate a causal link.Clinical trial registration: NCT04525105.

Diastasis recti abdominis and pelvic floor dysfunction in peri- and postmenopausal women: a cross-sectional study

Introduction: Diastasis recti abdominis (DRA) and pelvic floor dysfunction (PFD) occurs commonly with aging; however, little is known about what leads to these changes.Objective: We aimed to investigate and compare the presence or absence of DRA and PFD in peri- and postmenopausal women.Methods: This cross-sectional study involved 150 participants who answered questions on their sociodemographic and clinical profiles related to urinary and fecal incontinence and pelvic organ prolapse. Diastasis recti abdominis was diagnosed with a digital caliper.Results: Supra-umbilical diastasis occurred in 37.3% of cases, and 78.6% of participants with DRA had PFD. No significant differences existed between participants with and without DRA in terms of background and clinical variables. However, participants with DRA were 2.6 times more likely to have PFD than participants without DRA. Furthermore, the presence of DRA was significantly shown to be a risk factor for PFD on binary logistic regression analyses (p = .01, OR = 3.2).Conclusions: This cross-sectional study suggests that DRA is a predictive factor of PFD in women aged over 50 years.

Study protocol to investigate biomolecular muscle profile as predictors of long-term urinary incontinence in women with gestational diabetes mellitus

BACKGROUND

Pelvic floor muscles (PFM) and rectus abdominis muscles (RAM) of pregnant diabetic rats exhibit atrophy, co-localization of fast and slow fibers and an increased collagen type I/III ratio. However, the role of similar PFM or RAM hyperglycemic-related myopathy in women with gestational diabetes mellitus (GDM) remains poorly investigated. This study aims to assess the frequency of pelvic floor muscle disorders and pregnancy-specific urinary incontinence (PS-UI) 12 months after the Cesarean (C) section in women with GDM. Specifically, differences in PFM/RAM hyperglycemic myopathy will be evaluated.

METHODS

The Diamater is an ongoing cohort study of four groups of 59 pregnant women each from the Perinatal Diabetes Research Centre (PDRC), Botucatu Medical School (FMB)-UNESP (São Paulo State University), Brazil. Diagnosis of GDM and PS-UI will be made at 24-26 weeks, with a follow-up at 34-38 weeks of gestation. Inclusion in the study will occur at the time of C-section, and patients will be followed at 24-48 h, 6 weeks and 6 and 12 months postpartum. Study groups will be classified as (1) GDM plus PS-UI; (2) GDM without PS-UI; (3) Non-GDM plus PS-UI; and (4) Non-GDM without PS-UI. We will analyze relationships between GDM, PS-UI and hyperglycemic myopathy at 12 months after C-section. The mediator variables to be evaluated include digital palpation, vaginal squeeze pressure, 3D pelvic floor ultrasound, and 3D RAM ultrasound. RAM samples obtained during C-section will be analyzed for ex-vivo contractility, morphological, molecular and OMICS profiles to further characterize the hyperglycemic myopathy. Additional variables to be evaluated include maternal age, socioeconomic status, educational level, ethnicity, body mass index, weight gain during pregnancy, quality of glycemic control and insulin therapy.

DISCUSSION

To our knowledge, this will be the first study to provide data on the prevalence of PS-UI and RAM and PFM physical and biomolecular muscle profiles after C-section in mothers with GDM. The longitudinal design allows for the assessment of cause-effect relationships between GDM, PS-UI, and PFMs and RAMs myopathy. The findings may reveal previously undetermined consequences of GDM.

Effect of integrin β1 in the treatment of stress urinary incontinence by electrical stimulation

The aim of the present study was to investigate the protective effect of integrin β1 in the treatment of stress urinary incontinence (SUI) by electrical stimulation, and the underlying mechanisms by which electrical stimulation regulates the collagen metabolism of female vaginal wall fibroblasts (FVWFs). FVWFs obtained from the vaginal wall tissue of patients with (Ingelman-Sundberg scale; grade II, n=8; grade III, n=10) or without (n=8) SUI during gynecological operations were isolated by enzymatic digestion and subsequently identified by immunocytochemistry. Following this, cultured FVWFs were treated with an inhibitor of integrin β1, recombinant human integrin β1 and electrical stimulation (100 mv/mm, 2 h, 20 Hz), followed by total mRNA and protein extraction. mRNA and protein expression levels of integrin β1, transforming growth factor (TGF)-β1 and collagen (COL) I and III in FVWFs were quantified by reverse transcription-quantitative PCR (RT-qPCR) and western blot analysis respectively. Integrin β1, TGF-β1 and COL I and III expression levels were decreased in patients with SUI compared with healthy controls, and the grade III group had lower levels than the grade II group. Following electrical stimulation treatment, the expression levels of TGF-β1, COL I and III were enhanced in the grade II group, but not in the grade III group. Nevertheless, the inhibitor of integrin β1 reduced the protective effect of electrical stimulation in the grade II group. In addition, electrical stimulation combined with recombinant human integrin β1 could also protect cells from SUI in the grade III group. The present study provides evidence for the increased degradation of the extracellular matrix and integrin β1 in the vaginal wall tissues of patients with SUI, and the protective effect of electrical stimulation against SUI via integrin β1. These results provide a novel mechanism for the treatment of SUI using electrical stimulation.

Effects of multiple simulated birth traumas on urethral continence function in rats

Multiple vaginal parities have been reported to be an important risk factor for stress urinary incontinence (SUI). Simulated birth trauma with single vaginal distention (VD) has been used to induce the SUI condition in animals; however, the effect of multiple simulated birth traumas on the urethral continence function has not been well characterized. Therefore, we examined the effects of multiple VDs on urethral functions in vivo and the changes in gene expressions of several molecules in the urethra using female SD rats, which were divided into three groups; sham, VD-1 (single VD), and VD-3 groups (3 times of VDs every 2 wk). Two weeks after the final VD, leak point pressure (LPP) and urethral responses during sneezing were evaluated. Also, changes in mRNA levels of urethral molecules were quantified with RT-PCR.　The VD-1 group did not show any change in LPP with only a tendency of decrease in amplitudes of the urethral responses during sneezing (A-URS); however, the VD-3 group showed a significant decrease in LPP and urethral responses such as baseline urethral pressure and A-URS accompanied with SUI episodes during sneezing. Nicotinic receptor subtypes and transforming growth factor (TGF)-β1 were significantly increased in both VD-1 and VD-3 groups while TNF receptor (TNFR)-1, IL-6, collagens, and matrix metalloproteinases-9 were significantly increased only in the VD-3 group.　These data indicate that rats with multiple simulated birth traumas exhibit profound impairment of the urethral continence function and that these functional changes are associated with those in cytokines, extracellular matrix molecules, and nicotinic receptor subtypes in the urethra.

Mechanism of Mechanical Trauma-Induced Extracellular Matrix Remodeling of Fibroblasts in Association with Nrf2/ARE Signaling Suppression Mediating TGF-β1/Smad3 Signaling Inhibition

Stress urinary incontinence (SUI) is a common hygienic problem affecting the quality of women's life worldwide. In this research, we revealed the involvement and regulation of extracellular matrix (ECM) remodeling, oxidative damage, and TGF-β1 signaling in the pathological mechanisms of mechanical trauma-induced SUI. We found that excessive mechanical strain significantly increased apoptosis rate, decreased cell viability and ECM production, and broke the balance of MMPs/TIMPs compared with the nonstrain control (NC) group. The expression levels of TGFβ1, p-Smad3, Nrf2, GPx1, and CAT were downregulated, the production of ROS, 8-OHdG, 4-HNE, and MDA was increased, and the nuclear translocation of Smad2/3 was suppressed after 5333 μstrain's treatment. Both mTGF-β1 pretreatment and Nrf2 overexpression could reverse mechanical injury-induced TGFβ1/Smad3 signaling inhibition and ECM remodeling, whereas mTGF-β1 had no effect on Nrf2 expression. Nrf2 overexpression significantly alleviated mechanical injury-induced ROS accumulation and oxidative damage; in contrast, Nrf2 silencing exhibited opposite effects. Besides, vaginal distention- (VD-) induced in vivo SUI model was used to confirm the in vitro results; Nrf2 knockout aggravates mechanical trauma-induced LPP reduction, ECM remodeling, oxidative damage, and TGF-β1/Smad3 suppression in mice. Therefore, we deduce that mechanical injury-induced ECM remodeling might be associated with Nrf2/ARE signaling suppression mediating TGF-β1/Smad3 signaling inhibition. This might reflect a new molecular target for SUI researches.

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.

Cadherin-11 is a novel regulator of extracellular matrix synthesis and tissue mechanics

We discovered that Cadherin-11 (CDH11) regulates collagen and elastin synthesis, both affecting the mechanical properties and contractile function of animal tissues. Using a Cdh11-null mouse model, we observed a significant reduction in the mechanical properties [Youngs' modulus and ultimate tensile strength (UTS)] of Cdh11(-/-) as compared to wild-type (WT) mouse tissues, such as the aorta, bladder and skin. The deterioration of mechanical properties (Youngs' modulus and UTS) was accompanied by reduced collagen and elastin content in Cdh11(-/-) mouse tissues as well as in cells in culture. Similarly, knocking down CDH11 abolished collagen and elastin synthesis in human cells, and consequently reduced their ability to generate force. Conversely, engagement of CDH11 through homophilic interactions, led to swift activation of the TGF-β and ROCK pathways as evidenced by phosphorylation of downstream effectors. Subsequently, activation of the key transcription factors, MRTF-A (also known as MKL1) and MYOCD led to significant upregulation of collagen and elastin genes. Taken together, our results demonstrate a novel role of adherens junctions in regulating extracellular matrix (ECM) synthesis with implications for many important biological processes, including maintenance of tissue integrity, wound healing and tissue regeneration.

Roles and regulation of the matrix metalloproteinase system in parturition

Significant tissue destruction, repair, and remodeling are involved in parturition, which involves fetal membrane rupture, cervical ripening, and uterine contraction and its subsequent involution. Extracellular matrix degradation and remodeling by proteolytic enzymes, such as matrix metalloproteinases (MMPs), are required for the final steps of parturition. MMPs participate in physiological degradation and remodeling through their proteolytic activities on specific substrates, and are balanced by the action of their inhibitors. Disruption to this balance can result in pathological stress that ends with preterm or post-term birth or pre-eclampsia. In this review, we examine the roles and regulation of the MMP system in physiological and pathological labor, and propose a model that illustrates the mechanisms by which the MMP system contributes to these processes.

Evaluation of the relationship between the pelvic floor muscles and insulin resistance

PURPOSE

The aim of this study was to evaluate the pelvic floor muscles (PFMs) in women with insulin resistance (IR) using surface electromyography and to associate the results with insulin levels.

PATIENTS AND METHODS

Through an analytical, cross-sectional study, 86 women were evaluated and divided into two groups: a control group (n=35) and an IR group (n=51). Data were collected through detailed history-taking, physical examination, and biochemical analysis. Fasting insulin levels were used for diagnosing IR. Electromyography of the PFMs was used for analyzing the tone and maximal voluntary contraction (MVC). The measures of central tendency and linear regression models were used.

RESULTS

The average age was 25.3±4.5 years in the IR group and 27.2±4.4 years in the control group. The mean weight was 75.6±17.6 kg and 51.8±4.9 kg in the IR and control groups, respectively. Fasting insulin levels were 19.7±6.6 µIU/mL in the IR group and 5.4±1.8 µIU/mL in the control group (P<0.010). There were significant differences between the groups with regard to PFM tone (IR: 13.4±3.4 µV; control: 25.1±3.3 µV; P<0.001) and MVC (IR: 47.6±4.5 µV; control: 64.3±5.0 µV; P<0.001). Multiple linear regression analysis using the insulin levels as dependent variable showed a significant association for MVC (P=0.047), weight (P=0.017), and waist circumference (P=0.000).

CONCLUSION

Compared with the control group, the IR group showed lower electromyographic activity of the PFMs, and there was an association between insulin levels and electromyographic activity.

A mouse model of urofacial syndrome with dysfunctional urination

Urofacial syndrome (UFS) is an autosomal recessive disease with severe dysfunctional urination including urinary incontinence (UI). Biallelic mutations of HPSE2 are discovered from UFS patients, suggesting that HPSE2 is a candidate disease gene. Here, we show that deletion of Hpse2 is sufficient to cause the UFS-like phenotype in mice. Hpse2 knockout mutants display a distended bladder (megacystis) phenotype and abnormal voiding behavior similar to that found in patients. While Hpse2 is largely dispensable for detrusor smooth muscle and urothelial cell fate determination, the mutants have significantly lower rates of cell proliferation than wild-type littermate controls. All Hpse2 mutants have a growth retardation phenotype and die within a month after birth. Comprehensive blood chemistry and urinalysis indicate that Hpse2 mutants have renal dysfunction and malnutrition. We provide evidence that transforming growth factor beta (Tgfβ) signaling is attenuated at birth. However, Tgfβ activity is significantly enhanced at later stages when the urological phenotype is severe, and the mutant bladders have accumulated excessive amount of fibrotic tissue. Together, these findings strongly suggest that Hpse2 is a causative gene of human UFS and further uncover unexpected roles of Hpse2 in bladder physiology, tissue remodeling and Tgfβ signaling.

Female urinary incontinence during pregnancy and after delivery: Clinical impact and contributing factors

Urinary incontinence (UI) is a common condition affecting adult women of all ages and it could have a negative influence on quality of life. The etiology of UI is multifactorial, but some of the most important risk factors are obesity and ageing, as well as adverse obstetric events. Pregnancy and delivery per se have been implicated in the etiology of UI. Although several studies have demonstrated a direct association between UI and vaginal delivery in short, medium and long-term, the role of childbirth on the risk of UI remains controversial. The mechanical strain during delivery may induce injuries to the muscle, connective and neural structures. Vaginal birth can be associated with relaxation or disruption of fascial and ligamentous supports of pelvic organs. Parity, instrumental delivery, prolonged labor and increased birth weights have always been considered risk factors for pelvic floor injury. Also genetic factors have been recently raised up but still there are not appropriate guidelines or measures to reduce significantly the incidence of UI. The role of pelvic floor muscle training (PFMT) in the prevention and treatment of UI is still unclear. However, PFMT seems to be useful when supervised training is conducted and it could be incorporated as a routine part of women’s exercise programmes during pregnancy and after childbirth.

Urethral striated muscle and extracellular matrix morphological characteristics among mildly diabetic pregnant rats: translational approach

INTRODUCTION AND HYPOTHESIS

Diabetes mellitus (DM) during pregnancy is associated with high levels of urinary incontinence (UI) and pelvic floor muscle dysfunction. Mild DM can lead to changes in urethral striated muscle and extracellular matrix (ECM) in pregnant rats considering both structures as an entire system responsible for urinary continence.

METHODS

Ninety-two female Wistar rats were distributed in four experimental groups: virgin, pregnant, diabetic, and diabetic pregnant. In adult life, parental nondiabetic female rats were mated with nondiabetic male rats to obtain newborns. At the first day of birth, newborns received citrate buffer (nondiabetic group) or streptozotocin 100 mg/kg body weight, subcutaneous route (mild DM group). At day 21 of the pregnancy, the rats were lethally anesthetized and the urethra and vagina were extracted as a unit. Urethral and vaginal sections were cut and analyzed by: (a) cytochemical staining for ECM and muscle structural components, (b) immunohistochemistry to identify fast- and slow-muscle fibers, and (c) transmission electron microscopy for ultrastructural analysis of urethral striated muscle.

RESULTS

In comparison with the three control groups, variations in the urethral striated muscle and ECM from diabetic pregnant rats were observed including thinning, atrophy, fibrosis, increased area of blood vessels, mitochondria accumulation, increased lipid droplets, glycogen granules associated with colocalization of fast and slow fibers, and a steady decrease in the proportion of fast to slow fibers.

CONCLUSIONS

Mild DM and pregnancy can lead to a time-dependent disorder and tissue remodeling in which the urethral striated muscle and ECM has a fundamental function.

Activation of VEGF and ERK1/2 and improvement of urethral function by adipose-derived stem cells in a rat stress urinary incontinence model

OBJECTIVE

To investigate the injected autologous adipose-derived stem cells (ADSCs) in improving stress urinary incontinence in a rodent model of parturition-related stress incontinence and the possible mechanism.

METHODS

The 40 rats were developed stress urinary incontinence models by postpartum balloon dilation of the vagina for 4 hours followed by bilateral ovariectomy. ADSCs were isolated from the peri-ovarian fat and labeled with thymidine analog 5-ethynyl-2-deoxyuridine (EdU). Twenty stress urinary incontinence rats received peri-urethral injection of phosphate-buffered saline as the negative controls and the other 20 stress urinary incontinence rats received peri-urethral injection of EdU-labeled ADSCc. Twenty control rats underwent sham ovariectomy without balloon dilation and served as positive controls. Four weeks later, voiding function was assessed by cystometry. Urethral histologic examination (Masson trichrome stain, picrosirius red stain, Hart elastin stain, Gordon and Sweet stain, and immunohistochemical stain) and Western blot were performed on urethral tissues.

RESULTS

Both leak point pressure and bladder capacity were significantly increased in ADSC-treated rats, compared to the balloon-injured ovariectomized rats. Histologic examination revealed normalized appearance of the fibromuscular structure of the urethra as well as increased peri-urethral blood vessel density in ADSC-treated rats. On Western blot, vascular endothelial growth factor and P-extracellular signal-regulated kinases (ERKs)1/2 protein was expressed at a higher rate in tissues from ADSC-treated rats compared to phosphate-buffered saline-treated rats.

CONCLUSION

Peri-urethral injection of ADSCs is associated with more normal urinary function and urethral structure in rats with parturition-related incontinence. The activation of vascular endothelial growth factor and ERK1/2 may be responsible for the paracrine effects from ADSCs.