Genetics and the lower urinary tract

Long-term functional and psychosocial outcome in adolescents and young adults treated for lower urinary tract dysfunction in childhood

BACKGROUND

Lower urinary tract dysfunction (LUTD) in childhood might affect lower urinary tract function and psychological wellbeing later in life. This study presents long-term functional outcome, psychological outcome and quality of life (QOL) of adolescents and young adults treated for childhood LUTD compared to healthy age-matched controls. In addition, association with past treatment outcomes is evaluated.

STUDY DESIGN

A single-centre cross-sectional study of former patients treated in childhood (currently 16-26 years old) was conducted. Participants completed a survey composed from validated questionnaires: the Overactive Bladder Questionnaire, the Hospital Anxiety and Depression Scale, the Pediatric Quality of Life Inventory and the Short Form 36 Health Survey.

RESULTS

Fifty-two former patients (out of 133) agreed to participate and returned the survey (mean age 21 ± 4.1 years). Sixty-nine control subjects were included (mean age 21 ± 2.9 years). Urinary tract symptoms were more common in former patients than controls. Storage symptoms more frequently reported were (urge) urinary incontinence, stress urinary incontinence (SUI) and nocturia. Voiding symptoms more frequently reported were intermittency and feeling of incomplete emptying, Fig. 1. There were no differences in urinary tract symptoms or urinary incontinence subdivided by childhood treatment outcome (complete response, partial response or no response), respectively p = 0.17 and p = 0.58. Results of the overactive bladder questionnaire revealed higher urinary symptom bother scores (score 14 versus 5 p < 0.01) and lower disease-specific QOL (score 95 versus 98 p = 0.02) in former patients compared to controls. General QOL and psychosocial wellbeing were not significantly different between the two groups. A childhood treatment duration extending 2,5 years was an independent prognostic factor for subsequent urinary tract symptoms later in life (OR = 1.5, 95% CI 1.1-2.0). Psychological comorbidity was more often present in former patients (35%) versus controls (10%), p < 0.01.

CONCLUSION

Adolescents and young adults treated for childhood LUTD are more prone to report urinary tract symptoms later in life, especially if treatment duration was extensive. However general QOL and psychosocial wellbeing later in life are not or only mildly affected.

Genome-Wide Association Study for Urinary and Fecal Incontinence in Women

PURPOSE

Urinary incontinence and fecal incontinence are common disorders in women that negatively impact quality of life. In addition to known health and lifestyle risk factors, genetics may have a role in continence. Identification of genetic variants associated with urinary incontinence and fecal incontinence could result in a better understanding of etiologic pathways, and new interventions and treatments.

MATERIALS AND METHODS

We previously generated genome-wide single nucleotide polymorphism data from Nurses' Health Studies participants. The participants provided longitudinal urinary incontinence and fecal incontinence information via questionnaires. Cases of urinary incontinence (6,120) had at least weekly urinary incontinence reported on a majority of questionnaires (3 or 4 across 12 to 16 years) while controls (4,811) consistently had little to no urinary incontinence reported. We classified cases of urinary incontinence in women into stress (1,809), urgency (1,942) and mixed (2,036) subtypes. Cases of fecal incontinence (4,247) had at least monthly fecal incontinence reported on a majority of questionnaires while controls (11,634) consistently had no fecal incontinence reported. We performed a genome-wide association study for each incontinence outcome.

RESULTS

We identified 8 single nucleotide polymorphisms significantly associated (p <5×10^-8) with urinary incontinence located in 2 loci, chromosomes 8q23.3 and 1p32.2. There were no genome-wide significant findings for the urinary incontinence subtype analyses. However, the significant associations for overall urinary incontinence were stronger for the urgency and mixed subtypes than for stress. While no single nucleotide polymorphism reached genome-wide significance for fecal incontinence, 4 single nucleotide polymorphisms had p <10^-6.

CONCLUSIONS

Few studies have collected genetic data and detailed urinary incontinence and fecal incontinence information. This genome-wide association study provides initial evidence of genetic associations for urinary incontinence and merits further research to replicate our findings and identify additional risk variants.

Clinical epidemiological insights into urinary incontinence

INTRODUCTION AND HYPOTHESIS

Urinary incontinence (UI) is very common and heterogeneous among women with limited knowledge of progression or prognosis. Evidence based on clinical epidemiology can help to better understand the natural history of UI.

METHODS

We examine the challenges of UI definition and its subtypes, its impact on quality of life and health-seeking behavior. We review the proposed pathophysiology of UI subtypes and known risk factors as they relate to our current knowledge of the disease state. Finally, we emphasize the role of epidemiology in the process of acquiring new insight, improving knowledge, and translating this information into clinical practice.

RESULTS

Stress UI is most common overall, but mixed UI is most prevalent in older women. The three UI subtypes have some common risk factors, and others that are unique, but there remains a significant gap in our understanding of how they develop. Although the pathophysiology of stress UI is somewhat understood, urgency UI remains mostly idiopathic, whereas mixed UI is the least studied and most complex subtype. Moreover, there exists limited information on the progression of symptoms over time, and disproportionate UI health-seeking behavior. We identify areas of exploration (e.g., epigenetics, urinary microbiome), and offer new insights into a better understanding of the relationship among the UI subtypes and to develop an integrated construct of UI natural history.

CONCLUSION

Future epidemiological strategies using longitudinal study designs could play a pivotal role in better elucidating the controversies in UI natural history and the pathophysiology of its subtypes leading to improved clinical care.

Tadalafil effect on metabolic syndrome-associated bladder alterations: an experimental study in a rabbit model

INTRODUCTION

Metabolic syndrome (MetS) and lower urinary tract symptoms (LUTS) are often associated. Bladder detrusor hyper-contractility-a major LUTS determinant-is characterized by increased Ras homolog gene family, member A/Rho-associated protein kinase (RhoA/ROCK) signaling, which is often upregulated in MetS.

AIM

This study investigated the effects of tadalafil dosing on RhoA/ROCK signaling in bladder, in a rabbit model of high-fat diet (HFD)-induced MetS.

METHODS

Adult male rabbits feeding a HFD for 12 weeks. A subset of HFD animals was treated with tadalafil (2 mg/kg/day, 1 week: the last of the 12 weeks) and compared with HFD and control (feeding a regular diet) rabbits.

MAIN OUTCOME MEASURES

In vitro contractility studies to evaluate the relaxant effect of the selective ROCK inhibitor, Y-27632, in carbachol precontracted bladder strips. Evaluation of RhoA activation by its membrane translocation. Immunohistochemistry for ROCK expression has been performed to evaluate ROCK expression in bladder from the different experimental groups. mRNA expression of inflammation, pro-fibrotic markers by quantitative RT-PCR has been performed to evaluate the effect of tadalafil on MetS-induced inflammation and fibrosis within the bladder. The in vitro effect of tadalafil on RhoA/ROCK signaling in bladder smooth muscle cells was evaluated by using chemotaxis assay.

RESULTS

Bladder strips from HFD rabbits showed hyper-responsiveness to Y-27632, indicating RhoA/ROCK overactivity in HFD bladder compared with matched controls. Accordingly, the fraction of activated (translocated to the membrane) RhoA as well as ROCK expression are increased in HFD bladder. Tadalafil dosing normalized HFD-induced bladder hypersensitivity to Y-27632, by reducing RhoA membrane translocation and ROCK overexpression. Tadalafil dosing reduced mRNA expression of inflammatory, pro-fibrotic, and hypoxia markers. A direct inhibitory effect of tadalafil on RhoA/ROCK signaling in bladder smooth muscle cell was demonstrated by using chemotaxis assay. Pre-treatment with tadalafil inhibited both basal and PDGF-induced migration of bladder smooth muscle cells.

CONCLUSIONS

Tadalafil dosing reduced RhoA/ROCK signaling and smooth muscle overactivity in an animal model of MetS-associated bladder alterations. Our findings suggest a novel mechanism of action of tadalafil in alleviating LUTS in MetS patients.

What is the role for biomarkers for lower urinary tract disorders? ICI-RS 2013

AIMS

A biomarker is an entity that measures a normal or pathological process, or the response to an intervention. A biomarker must measure exclusively and be sufficiently sensitive to the process of interest. Alternatively, a biomarker may give clues regarding the underlying pathology of the condition and be a useful research or specialist tool. If a biomarker is to be of practical benefit then it must also be economical and practical to use. This article will consider chemical moieties as biomarkers, although in principle physical markers (e.g., bladder wall thickness) could also be defined as such.

RESULTS AND CONCLUSIONS

The validation of a biomarker for detrusor overactivity (DO) must appreciate the fact that the condition is likely to multifactorial and thus no single entity may be sufficiently selective and sensitive. However, more specific conditions, such as bladder pain associated with DO, may make the biomarker search easier. Several prospective agents including antiproliferative factor (APF) and epidermal growth factors (EGF) are discussed. Several urinary biomarkers, including neurotrophins (NGF, BDNF) and cytokines, and a serum marker, C-reactive protein, are considered as reaching the above criteria. All suffer from relatively poor lack of discrimination, as they all change in response to other, often inflammatory, conditions; BDNF may offer the highest expectations. Urinary ATP has also been proposed as a DO/OAB biomarker but requires further evaluation. Finally genetic markers offer potential to understand more about the pathophysiology of DO/OAB. The increasing availability of genome-wide association studies and micro-RNA assays offer genetic markers as a new generation of biomarkers. Neurourol. Urodynam. 33:602-605, 2014. © 2014 Wiley Periodicals, Inc.

Identification of six loci associated with pelvic organ prolapse using genome-wide association analysis

OBJECTIVE

There is evidence that both environmental and genetic factors contribute to pelvic organ prolapse. We conducted a genome-wide association study to investigate whether common genetic variants modify the risk of pelvic organ prolapse.

METHODS

We recruited women who had been evaluated and treated for pelvic organ prolapse at the University of Utah from 1996 to 2008 and their affected female relatives. Those in the case group were genotyped on the Illumina 550K platform. We genetically matched 2,976 white control participants available from Illumina as the control group. Association tests were adjusted for related participants using two different software programs: EMMAX and Genie. Confirmation of findings was performed in a cohort of Dutch women (n=76) with recurrent pelvic organ prolapse and family history of pelvic organ prolapse.

RESULTS

The Utah study sample included 115 case group participants treated for pelvic organ prolapse, in most case group participants with surgery (n=78) or repeat surgery (n=35). Results from association analyses using EMMAX software identified five single-nucleotide polymorphisms (SNPs) significantly associated with pelvic organ prolapse (P<1×10). Independent association analysis with Genie software identified three of the same SNPs and one additional SNP. The six SNPs were located at 4q21 (rs1455311), 8q24 (rs1036819), 9q22 (rs430794), 15q11 (rs8027714), 20p13 (rs1810636), and 21q22 (rs2236479). Nominally significant findings (P<.05) or findings trending toward significance (P<.1) were observed for five of the six SNPs in the Dutch cohort.

CONCLUSION

Six SNPs have been identified that are significantly associated with pelvic organ prolapse in high-risk familial case group participants and that provide evidence for a genetic contribution to pelvic organ prolapse.

LEVEL OF EVIDENCE

II.

Are polymorphisms of the β(3)-adrenoceptor gene associated with an altered bladder function?

AIMS

As the presence of a Trp64Arg polymorphism of the gene encoding the β(3)-adrenoceptor (B3AR) has been linked to the presence of overactive bladder, we investigated whether additional polymorphisms are detectable in this gene and explore their relationships parameters related to lower urinary tract function.

METHODS

The coding region and adjacent stretches of the B3AR gene was sequenced in 91 patients. In total, 1015 patients from a single academic hospital were genotyped for the presence of two single nucleotide polymorphisms. Symptom scores and parameters from pressure-flow studies were analyzed relative to genotype in the B3AR gene.

RESULTS

No frequent novel polymorphisms were detected in the coding region. Five polymorphisms were found in the non-coding region of the gene but were in complete linkage with the 64Arg allele. Out of 32 parameters including bladder compliance, only prostate size was weakly (44 vs. 39 mL) but significantly associated with the 64Arg allele, but was not mirrored by an association with prostate-specific antigen levels.

CONCLUSIONS

Our data do not support the hypothesis that polymorphisms in the B3AR gene are associated with alterations of bladder function.

Alterations in connective tissue metabolism in stress incontinence and prolapse

PURPOSE

We describe current knowledge about collagen/elastin and extracellular matrix metabolism in the genitourinary tract with special emphasis on stress urinary incontinence. We also explored the influence of genetics and reproductive hormones on extracellular matrix metabolism.

MATERIALS AND METHODS

We performed a MEDLINE® search from 1995 to February 2011 using the key words stress urinary incontinence, pelvic organ prolapse, extracellular matrix, collagen, elastin, matrix metalloproteinase, collagenase, tissue inhibitors of matrix metalloproteinase, elastin metabolism, elastase, connective tissue, supportive tissue, mechanical stress, biomechanical properties, selective estrogen receptor modulators, transforming growth factor-β and wound healing.

RESULTS

The literature searched produced data on 4 areas of significance for extracellular matrix metabolism in patients with stress urinary incontinence and prolapse, including collagen, elastin and transforming growth factor-β. Data on collagen metabolism continue to support the hypothesis of increased turnover involving matrix metalloproteinases and serine proteases in pelvic tissues of affected individuals. Elastin metabolism studies suggest increased degradation but also abnormal elastin fiber synthesis. Epidemiological data indicate a genetic predisposition to abnormal extracellular matrix in affected individuals while human tissue and animal models reveal differential expression of candidate genes involved in structural proteins. Transforming growth factor-β pathways have been documented to be involved in stress urinary incontinence in human tissues and animal models. Finally, these extracellular matrix metabolisms are modulated by reproductive hormones and selective estrogen receptor modulators.

CONCLUSIONS

Pelvic tissue from women with stress urinary incontinence and pelvic organ prolapse show a genetic predisposition to abnormal extracellular matrix remodeling, which is modulated by reproductive hormones, trauma, mechanical stress load and aging. This progressive remodeling contributes to stress urinary incontinence/pelvic organ prolapse by altering normal tissue architecture and mechanical properties.

Pelvic organ distribution of mesenchymal stem cells injected intravenously after simulated childbirth injury in female rats

The local route of stem cell administration utilized presently in clinical trials for stress incontinence may not take full advantage of the capabilities of these cells. The goal of this study was to evaluate if intravenously injected mesenchymal stem cells (MSCs) home to pelvic organs after simulated childbirth injury in a rat model. Female rats underwent either vaginal distension (VD) or sham VD. All rats received 2 million GFP-labeled MSCs intravenously 1 hour after injury. Four or 10 days later pelvic organs and muscles were imaged for visualization of GFP-positive cells. Significantly more MSCs home to the urethra, vagina, rectum, and levator ani muscle 4 days after VD than after sham VD. MSCs were present 10 days after injection but GFP intensity had decreased. This study provides basic science evidence that intravenous administration of MSCs could provide an effective route for cell-based therapy to facilitate repair after injury and treat stress incontinence.

[Urogynecology, overactive bladder, and neurourology]

This overview presents new results regarding urogynecology, overactive bladder, and neurourology. The importance of interdisciplinary pelvic floor centers and Burch colposuspension are discussed.

Genetics of pelvic organ prolapse: crossing the bridge between bench and bedside in urogynecologic research

An increasing number of scientists have studied the molecular and biochemical basis of pelvic organ prolapse (POP). The extracellular matrix content of the pelvic floor is the major focus of those investigations and pointed for potential molecular markers of the dysfunction. The identification of women predisposed to develop POP would help in the patients' management and care. This article includes a critical analysis of the literature up to now; discusses implications for future research and the role of the genetics in POP.

The clinical relevance of cell-based therapy for the treatment of stress urinary incontinence

Stress urinary incontinence is a common disorder affecting the quality of life for millions of women worldwide. Effective surgical procedures involving synthetic permanent meshes exist, but significant short- and long-term complications occur. Cell-based therapy using autologous stem cells or progenitor cells presents an alternative approach, which aims at repairing the anatomical components of the urethral continence mechanism. In vitro expanded progenitor cells isolated from muscle biopsies have been most intensely investigated, and both preclinical trials and a few clinical trials have provided proof of concept for the idea. An initial enthusiasm caused by positive results from early clinical trials has been dampened by the recognition of scientific irregularities. At the same time, the safety issue for cell-based therapy has been highlighted by the appearance of new and comprehensive regulatory demands. The influence on the cost effectiveness, the clinical relevance and the future perspectives of the present clinical approach are discussed.

Novel biomarkers for overactive bladder

Biomarkers constitute any objectively measurable indicator of a biological process. The classic biomarker used in the diagnosis of overactive bladder (OAB) has been detrusor overactivity, which is assessed urodynamically. In the search for a reliable, noninvasive alternative to urodynamics, interest has focused on genetic, imaging, and urinary factors. Along with other cytokines detectable in urine, prostaglandin E2 and nerve growth factor are indicators of low-grade inflammation. Although they correlate with OAB symptom severity, they have not been shown to have independent prognostic benefit. Imaging biomarkers have been investigated since the earliest days of video urodynamics. Despite extensive research on the ultrasonographic estimation of bladder wall thickness, further standardization of the technique is required before conclusions can be reached regarding diagnostic accuracy. Genetic factors contribute approximately half of the total risk for urgency incontinence. Functional polymorphisms of the cytochrome P450 IID6 gene significantly alter the metabolism of some commonly used anticholinergic drugs, but no genetic loci that influence risk of OAB have been definitively identified. The first genome-wide association studies for OAB are in progress, and should identify new susceptibility genes. Although current putative biomarkers correlate with OAB severity, much future work is required to assess their prognostic value, and establish their role in clinical practice.