Effects of Age and Multiple Vaginal Births on Lower Urinary Tract Structure and Function in Nonhuman Primates / 대한배뇨장애요실금학회지

Purpose@#The relative roles of urinary sphincter damage, aging, and childbirth in stress urinary incontinence (SUI), have not been established. This study was performed to elucidate the roles of these factors. @*Methods@#The study included: (1) 8 female cynomolgus monkeys (17–19 years of age and 7–8 vaginal births each); (2) six 5-yearold nulliparous monkeys with surgically created chronic urinary sphincter dysfunction; and (3) six 5-year-old, nulliparous, nosurgery controls. Sedated abdominal leak point pressure (ALPP) and maximum urethral sphincter pressures (MUP) were measured. Sphincters, bladders, and pelvic support muscles were quantified for collagen content. Additionally, bladders were analyzed for collagen fiber thickness, length, and angle using CT-FIRE analysis of Picrosirius red-stained tissues. @*Results@#Resting MUP values were similar in the controls and older multiparous monkeys (P>0.05). However, aging and multiple births reduced pudendal nerve-stimulated increases in MUP (P0.05 vs. young groups). Bladder collagen content was greater, and muscle content less, in the old multiparous monkeys (P<0.05 vs. younger groups). Additionally, collagen fibers were thicker and more angular in the bladders of the older multiparous monkeys than in the other nonhuman primate groups (P<0.05). Pelvic support muscles had higher collagen and lower muscle content in the older multiparous monkeys than in the younger groups of monkeys (P<0.05). @*Conclusions@#SUI, associated with aging and multiple childbirths, appeared to be more strongly associated with bladder dysfunction, reduced pelvic muscle support, and the compensatory response to neural stimulation than with selective urinary sphincter dysfunction.

Oxidative Stress and Its Relation to Lower Urinary Tract Symptoms / 대한배뇨장애요실금학회지

The aim of this review is to discuss how to link lower urinary tract symptoms (LUTS) and oxidative stress (OS) and to define relevant targets for therapeutic intervention. Narrative review based on published literature. Many of the multifactorial pathophysiological mechanisms behind LUTS can initiate reactive oxygen species (ROS) generation. Assuming that OS is a consequence rather than a primary cause of LUTS it seems reasonable to identify both the disease mechanism initiating LUTS, and the source of ROS involved. There are many possible sources of ROS overproduction, but the NADPH oxidase (NOX) family of enzymes is the primary source; NOX activation in turn, may result in the activation of secondary ROS sources, i.e., ROS-dependent ROS production. Selective NOX inhibition therefore seems an attractive therapeutic strategy in LUTS treatment. The finding of NOX2 localization to centers in the brain associated with micturition control, opens up for further studies of NOX involvement in the central control of micturition, normally and in disease. Further information on the localization of the different isoforms of NOX in the LUT e.g., the bladder wall and its components and the prostate, is desirable. To optimize treatment, the pathophysiological mechanism initiating LUTS, and the activated isoform of NOX, should be identified. Unfortunately, in most cases of LUTS this is currently not possible. Even if selective NOX inhibitors have entered the clinical trial stage for treatment of disorders other than LUT dysfunction, their efficacy for LUTS treatment has to be demonstrated. If this can be achieved, an attractive approach would be combination of selective NOX inhibition with established drug therapies.

Cell Versus Chemokine Therapy Effects on Cell Mobilization to Chronically Dysfunctional Urinary Sphincters of Nonhuman Primates / 대한배뇨장애요실금학회지

PURPOSE: A major question remaining in approaches to tissue engineering and organ replacement is the role of native mobilized native cells in the regeneration process of damaged tissues and organs. The goal of this study was to compare the cell mobilizing effects of the chemokine CXCL12 and cell therapy on the urinary sphincter of nonhuman primates (NHP) with chronic intrinsic urinary sphincter dysfunction. METHODS: Either autologous lenti-M-cherry labeled skeletal muscle precursor cells (skMPCs) or CXCL12 were injected directly into the sphincter complex of female NHPs with or without surgery-induced chronic urinary sphincter dysfunction (n=4/treatment condition). All monkeys had partial bone marrow transplantation with autologous lenti-green fluorescent protein (GFP) bone marrow cells prior to treatment. Labeled cells were identified, characterized and quantified using computer-assisted immunohistochemistry 6 months posttreatment. RESULTS: GFP-labeled bone marrow cells (BMCs) were identified in the bone marrow and both BMCs and skMPCs were found in the urinary sphincter at 6-month postinjection. BMCs and skMPCs were present in the striated muscle, smooth muscle, and lamina propria/urothelium of the sphincter tissue. Sphincter injury increased the sphincter content of BMCs when analyzed 6-month postinjection. CXCL12 treatment, but not skMPCs, increased the number of BMCs in all layers of the sphincter complex (P < 0.05). CXCL12 only modestly (P=0.15) increased the number of skMPCs in the sphincter complex. CONCLUSIONS: This dual labeling methodology now provides us with the tools to measure the relative number of locally injected cells versus bone marrow transplanted cells. The results of this study suggest that CXCL12 promotes mobilization of cells to the sphincter, which may contribute more to sphincter regeneration than injected cells.

Animal Modelling of Interstitial Cystitis/Bladder Pain Syndrome / 대한배뇨장애요실금학회지

The etiology of interstitial cystitis/bladder pain syndrome (IC/BPS) remains elusive and may involve multiple causes. To better understand its pathophysiology, many efforts have been made to create IC/BPS models. Most existing models of IC/BPS strive to recreate bladder-related features by applying noxious intravesical or systemic stimuli to healthy animals. These models are useful to help understand various mechanisms; however, they are limited to demonstrating how the bladder and nervous system respond to noxious stimuli, and are not representative of the complex interactions and pathophysiology of IC/BPS. To study the various factors that may be relevant for IC/BPS, at least 3 different types of animal models are commonly used: (1) bladder-centric models, (2) models with complex mechanisms, and (3) psychological and physical stressors/natural disease models. It is obvious that all aspects of the human disease cannot be mimicked by a single model. It may be the case that several models, each contributing to a piece of the puzzle, are required to recreate a reasonable picture of the pathophysiology and time course of the disease(s) diagnosed as IC/BPS, and thus to identify reasonable targets for treatment.

Neuropelveology: An Emerging Discipline for the Management of Chronic Pelvic Pain / 대한배뇨장애요실금학회지

Chronic pelvic pain (CPP) is a common condition involving multiple, organ-specific medical specialties, each with its own approach to diagnosis and treatment. Management requires knowledge of the interplay between pelvic organ function and neuro-functional anatomy, and of the neurologic and psychological aspects of CPP, but no current specialty fully encompasses this approach. Neuropelveology is an emerging discipline focusing on pathologies of the pelvic nervous system on a cross-disciplinary basis. It involves a neurological/neurosurgical approach, combining the knowledge required for a proper neurologic diagnosis, confirmation by transvaginal/transrectal examination of the pelvic nerves, and advanced laparoscopic surgery in selected cases of CPP. The management of CPP requires multidisciplinary contributions, and neuropelveology may offer an educational framework for the interdisciplinary exchange of knowledge between clinical physicians and basic researchers.

On the Site and Mechanism of Action of β₃-Adrenoceptor Agonists in the Bladder / 대한배뇨장애요실금학회지

The clinical success of mirabegron as the first β₃-adrenoceptor (AR) agonist for treatment of the overactive bladder (OAB) syndrome, has resulted in substantial interest in its site and mechanism of action. Even if the adrenergic innervation of the bladder and urethra has been well studied, the location(s) of β₃-ARs in different structures within the bladder wall and urethra, and the mode(s) of action of β₃-AR stimulation have still not been established. The recent demonstration of β₃-ARs on cholinergic nerve terminals with no immunoreactivity in urothelium or detrusor smooth muscle, is not in agreement with previous morphological studies, and functional data strongly suggest that β₃-ARs can be found these structures. However, recent studies suggest that the β₃-ARs on detrusor smooth muscle may not be the functionally most relevant. The assumption that β₃-AR activation during bladder filling inhibits acetylcholine release from parasympathetic neurons by a prejunctional mechanism and that this decreases bladder micromotions that generate afferent activity, is an attractive hypothesis. It does not exclude that other mechanisms may be contributing, and supports combined approaches to reduce afferent activity for treatment of the OAB syndrome.

Current Pharmacologic Approaches in Painful Bladder Research: An Update / 대한배뇨장애요실금학회지

The symptoms of interstitial cystitis (IC)/bladder pain syndrome (BPS) may have multiple causes and involve many contributing factors. Traditional treatments (intravesical instillations) have had a primary focus on the bladder as origin of symptoms without adequately considering the potential influence of other local (pelvic) or systemic factors. Systemic pharmacological treatments have had modest success. A contributing factor to the low efficacy is the lack of phenotyping the patients. Individualized treatment based on is desirable, but further phenotype categorization is needed. There seems to be general agreement that IC is a unique disease and that BPS is a syndrome with multiple pathophysiologies, but this has so far not been not been well reflected in preclinical research with the aim of finding new pharmacological treatments. Current research approaches, including anti-nerve growth factor treatment, anti-tumor necrosis factor-α treatment, activation of SHIP1 (AQX-1125), and P2X3 receptor antagonists, and α1-adrenoceptor antagonists are potential systemic treatments, implying that not only the bladder is exposed to the administered drug, which may be beneficial if the IC/BPS is a bladder manifestation of a systemic disease, or negative (adverse effects) if it is a local bladder condition. Local treatment approaches such as the antagonism of Toll-like receptors (which still is only experimental) and intravesical liposomes (with positive proof-of-concept), may have the advantages of a low number of systemic adverse effects, but cannot be expected to have effects on symptoms generated outside the bladder. Assessment of which of the treatment approaches discussed in this review that can be developed into useful therapies requires further studies.

Drug therapy of overactive bladder - What is coming next?

After the approval and introduction of mirabegron, tadalafil, and botulinum toxin A for treatment of lower urinary tract symptoms/overactive bladder, focus of interest has been on their place in therapy versus the previous gold standard, antimuscarinics. However, since these agents also have limitations there has been increasing interest in what is coming next - what is in the pipeline? Despite progress in our knowledge of different factors involved in both peripheral and central modulation of lower urinary tract dysfunction, there are few innovations in the pipe-line. Most developments concern modifications of existing principles (antimuscarinics, beta3-receptor agonists, botulinum toxin A). However, there are several new and old targets/drugs of potential interest for further development, such as the purinergic and cannabinoid systems and the different members of the transient receptor potential channel family. However, even if there seems to be good rationale for further development of these principles, further exploration of their involvement in lower urinary tract function/dysfunction is necessary.