Urothelial Dysfunction and Chronic Inflammation in Diabetic Patients with Overactive Bladder

Diabetes mellitus, systemic inflammation and overactive bladder

Background

Increasing evidence emphasizes the potential relationship between diabetes and OAB (overactive bladder). However, large population epidemiology is still lacking.

Methods

This cross-sectional study included six cycle NHANES surveys, with a total of 23863 participants. Logistic regression models were constructed to analyze the association between diabetes mellitus, diabetes-related markers, and inflammatory biomarkers with OAB. Restricted cubic splines were used to analyze the non-linear associations. Mediating analysis was performed to test the effect of inflammatory biomarkers on the relationship between diabetes-related markers and OAB. Finally, machine learning models were applied to predict the relative importance and construct the best-fit model.

Results

Diabetes mellitus participants' OAB prevalence increased by 77% compared with non-diabetes. As the quartiles of diabetes-related markers increased, the odds of OAB monotonically increased in three models (all p for trend < 0.001). Glycohemoglobin exhibited a linear association with OAB (p for nonlinearity > 0.05). White blood cells significantly mediated the associations between diabetes-related markers (glycohemoglobin, fasting glucose, and insulin) with OAB, and the proportions were 7.23%, 8.08%, and 17.74%, respectively (all p < 0.0001). Neutrophils partly mediated the correlation between (glycohemoglobin, fasting glucose, and insulin) and OAB at 6.58%, 9.64%, and 17.93%, respectively (all p < 0.0001). Machine learning of the XGBoost model constructs the best fit model, and XGBoost predicts glycohemoglobin is the most important indicator on OAB.

Conclusion

Our research revealed diabetes mellitus and diabetes-related markers were remarkably associated with OAB, and systemic inflammation was an important mediator of this association.

Current optimal pharmacologic therapies for overactive bladder

INTRODUCTION

Overactive bladder (OAB) is a common syndrome in adults. Current pharmacologic treatment includes antimuscarinic agents and β-3 adrenoceptor agonists. For non-responders to oral medication, intravesical injection of botulinum toxin A (BoNT-A) is an effective option. However, these treatments have potential adverse events and should be cautiously selected for appropriate patients. This review presents the recently published results of clinical trials and studies for patients with OAB and the underlying pathophysiology of OAB. Appropriate medical therapy based on pathophysiology of OAB is also presented.

AREAS COVERED

Literature search from Pubmed from 2001 to 2023 including clinical background, pharmacology, and clinical studies for OAB medications.

EXPERT OPINION

Treatment of OAB syndrome with any antimuscarinic or β-3 adrenoceptor agonist is feasible as a first-line approach. For patients with suboptimal therapeutic effect to full-dose antimuscarinics or mirabegron, combination with both drugs can improve efficacy. Intravesical BoNT-A 100-U injection provides therapeutic effects for refractory OAB. Patients who are refractory to initial pharmacotherapies should be investigated for the underlying pathophysiology; then an appropriate medication can be added, such as an α1-blocker or anti-inflammatory agents. Patient education about behavioral modification and therapies should always be provided with oral medication or BoNT-A injection for OAB patients.

Diabetes causes NLRP3-dependent barrier dysfunction in mice with detrusor overactivity but not underactivity

Approximately half of the patients with diabetes develop diabetic bladder dysfunction (DBD). The initiation and progression of DBD is largely attributed to inflammation due to dysregulated glucose and the production of toxic metabolites that activate the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome. NLRP3 activation leads to the production and release of proinflammatory cytokines and causes urothelial pyroptosis, a form of programmed cell necrosis, which we hypothesize compromises urothelial barrier integrity. Here, we investigated how NLRP3-dependent inflammation impacts barrier function during the progression of diabetes using a type 1 diabetic female Akita mouse model that progresses from an early overactive to a late underactive detrusor phenotype at 15 and 30 wk, respectively. To determine the specific role of NLRP3, Akita mice were crossbred with mice lacking the NLRP3 gene. To determine barrier function, permeability to small molecules was assessed, ex vivo using Evans blue dye and in vivo using sulfo-NHS-biotin. Both ex vivo and in vivo permeabilities were increased in diabetic mice at 15 wk. Expression of uroplakin and tight junction components was also significantly downregulated at 15 wk. Interestingly, diabetic mice lacking the NLRP3 gene showed no evidence of barrier damage or downregulation of barrier genes and proteins. At the 30-wk time point, ex vivo and in vivo barrier damage as well as barrier component downregulation was no longer evident in diabetic mice, suggesting urothelial repair or remodeling occurs between the overactive and underactive stages of DBD. Collectively, these findings demonstrate the role of NLRP3-mediated inflammation in urothelial barrier damage associated with detrusor overactivity but not underactivity.NEW & NOTEWORTHY This is the first study to demonstrate that NLRP3-mediated inflammation is responsible for urothelial barrier damage in type 1 diabetic female Akita mice with an overactive bladder. Eliminating the NLRP3 gene in these diabetic mice prevented barrier damage as a result of diabetes. By the time female Akita mice develop an underactive phenotype, the urothelial barrier has been restored, suggesting that inflammation is a critical causative factor early in the development of diabetic bladder dysfunction.

Inflammation triggered by the NLRP3 inflammasome is a critical driver of diabetic bladder dysfunction

Diabetes is a rapidly expanding epidemic projected to affect as many as 1 in 3 Americans by 2050. This disease is characterized by devastating complications brought about high glucose and metabolic derangement. The most common of these complications is diabetic bladder dysfunction (DBD) and estimates suggest that 50-80% of patients experience this disorder. Unfortunately, the Epidemiology of Diabetes Interventions and Complications Study suggests that strict glucose control does not decrease ones risk for incontinence, although it does decrease the risk of other complications such as retinopathy, nephropathy and neuropathy. Thus, there is a significant unmet need to better understand DBD in order to develop targeted therapies to alleviate patient suffering. Recently, the research community has come to understand that diabetes produces a systemic state of low-level inflammation known as meta-inflammation and attention has focused on a role for the sterile inflammation-inducing structure known as the NLRP3 inflammasome. In this review, we will examine the evidence that NLRP3 plays a central role in inducing DBD and driving its progression towards an underactive phenotype.

Potential role of oxidative stress in the pathogenesis of diabetic bladder dysfunction

Diabetes mellitus is a chronic metabolic disease, posing a considerable threat to global public health. Treating systemic comorbidities has been one of the greatest clinical challenges in the management of diabetes. Diabetic bladder dysfunction, characterized by detrusor overactivity during the early stage of the disease and detrusor underactivity during the late stage, is a common urological complication of diabetes. Oxidative stress is thought to trigger hyperglycaemia-dependent tissue damage in multiple organs; thus, a growing body of literature has suggested a possible link between functional changes in urothelium, muscle and the corresponding innervations. Improved understanding of the mechanisms of oxidative stress could lead to the development of novel therapeutics to restore the redox equilibrium and scavenge excessive free radicals to normalize bladder function in patients with diabetes.

Platelet-to-Lymphocyte Ratio Predicts the Presence of Diabetic Neurogenic Bladder

PURPOSE

Diabetic neurogenic bladder (DNB) has been widely recognized in recent years. It is common in patients with long-term diabetes and may also lead to many severe complications. Although there has been widespread evidence that inflammation is involved in the development of some diabetic complications, there is little evidence that this can also occur in the bladder. In recent years, platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) have been viewed as potential novel markers of inflammatory responses. This study was designed to evaluate the relationship between the presence of DNB and the PLR and NLR.

PATIENTS AND METHODS

A total of 371 cases of T2DM patients were included in this retrospective study. Patients were divided into two groups, with 115 diabetic subjects diagnosed with diabetic neurogenic bladder and 256 control subjects without DNB. The independent predictors of DNB were analyzed using logistic regression.

RESULTS

Compared with patients without DNB, the mean PLR and NLR were significantly higher in those with DNB (p < 0.001). Based on the logistic regression, PLR was found to be an independent risk factor for DNB (odds ratio [OR]: 1.408, 95% confidence interval [CI]: 1.248-1.617). From the receiver operating characteristic (ROC) curve, using PLR as indicative of DNB was expected to be 101.1949, and it generated a sensitivity and specificity value of 89.6% and 23.4%, respectively. The area under the curve (AUC) was also found to be 0.899 (95% CI: 0.865-0.932).

CONCLUSION

In our study, PLR and NLR were significantly higher for patients with DNB. The PLR was found to be a risk factor in the presence of DNB after correcting for possible confounding factors. Considering the severe complications associated with DNB, patients with elevated PLR should be seriously cared for in clinics.

Lower Urinary Tract Symptoms Among Females with Rheumatoid Arthritis: A Prospective Cross-Sectional Study

PURPOSE

To assess the presence of lower urinary tract symptoms (LUTS) in rheumatoid arthritis (RA) female patients with assessment of LUTS and its impact on quality of life (QoL).

PATIENTS AND METHODS

A prospective, cross-sectional study of female patients with RA was conducted. Demographics and clinical data, Bristol Female Lower Urinary Tract Symptoms questionnaire (BFLUTS), and the RA Disease Activity Score 28 (DAS28) were all collected. A correlation has been made between all variables to assess the factors that induce LUTS in RA and the impact on QoL.

RESULTS

Eighty-nine patients were enrolled. About 94.4% of RA patients had at least one symptom of LUTS. Concerning DAS28, 55.1% had moderate disease activity and 16.9% had high disease activity, which was not significantly associated with BFLUTS or QoL. The prevalence of overactive bladder syndrome symptoms (OAB: frequency, urgency, nocturia, and urgency incontinence) were found to be 65.2%, 59.6%, 56.2%, and 30.3%, respectively. Stress incontinence was prevalent in 40.4% of patients. The overall interference with life was evident in 27 (30.3%) patients secondary to LUTS. Body mass index (BMI) was positively and significantly correlated with the presence of storage symptoms (r = 0.306, p = 0.004) and with the total BFLUTS (r = 0.251, p = 0.018). BFLUTS subdomains and total scores were significantly correlated to poor QoL. The correlation of the BFLUTS QoL was found to be r = 0.584, p < 0.001 with storage symptoms, r = 0.399, p < 0.001 with voiding symptoms, and r = 0.757, p < 0.001 with incontinence.

CONCLUSION

LUTS is a prominent and significant disability that directly affects QoL in RA. BMI is an independent factor that is linked to LUTS in RA patients.

Deficits of urothelial cell proliferation, cytoskeleton, and barrier function protein expressions in patients with recurrent and persistent urinary tract infections

OBJECTIVES

Recurrent urinary tract infection (rUTI) is a common infectious disease in women. This study investigated the urothelial cell proliferation, the cytoskeleton, barrier proteins, and inflammatory protein expression in women with rUTIs.

METHODS

Female patients with recurrent or persistent UTIs were recruited. Bladder mucosal specimens were investigated by Western blot and immunohistochemical staining for the urothelial cytoskeleton proteins cytokeratin 5 (CK5), CK14, and CK20; proteins involved in cellular proliferation, including CD34, sonic hedgehog (SHH), and tumor protein 63 (TP63); barrier proteins zonula occludens 1 (ZO-1) and E-cadherin; inflammatory proteins p38 and tryptase; and proapoptotic proteins Bcl2-associated agonist of cell death protein (BAD), Bcl2-associated X protein (BAX), and caspase-3. Women with stress urinary incontinence without bladder symptoms served as controls. Bladder specimens from 18 recurrent UTI patients with rUTIs and 12 persistent UTIs, and 17 controls were analyzed, and protein expressions were compared between the three groups.

RESULTS

Cell proliferation protein expression for CD34, SHH, and TP63 was significantly lower in the urothelium of patients with rUTIs than in controls. Expression of CK5 increased, whereas CK20 decreased significantly in rUTIs compared with those of controls. Apoptotic proteins BAD, BAX, and caspase-3 were significantly higher in patients with rUTIs. However, barrier proteins ZO-1 and E-cadherin, and tryptase were not significantly lower in patients with rUTIs.

CONCLUSION

Deficits in expression of proteins involved in urothelial cell proliferation, cytoskeleton, and barrier function were noted in patients with rUTIs. These urothelial deficits may be due to deficient proliferation and differentiation resulting in inadequate urothelial barrier function and further in rUTIs.

The Pharmacological Mechanism of Diabetes Mellitus-Associated Overactive Bladder and Its Treatment with Botulinum Toxin A

Diabetes mellitus (DM) is an independent risk factor for overactive bladder (OAB). The pathophysiology of DM-associated OAB is multifactorial and time-dependent. Diabetic bladder dysfunction is highly associated with diabetic complications, mainly including diabetic neuropathy and atherosclerosis. Chronic systemic inflammation and bladder urothelial inflammation may contribute to the onset of OAB. Intravesical botulinum toxin A (BoNT-A) injection has proved to be a successful treatment for idiopathic and neurogenic OAB. BoNT-A can inhibit the efferent pathways of the bladder as well as the chronic inflammation and hypersensitivity via the afferent pathways. We conducted a review of the published literature in Pubmed using a combination of two keywords, namely “botulinum toxin A” (BoNT-A) and “overactive bladder”, with or without the additional keywords “detrusor overactivity”, “diabetes mellitus”, “inflammation”, and “urodynamic study”. We also reviewed the experience of our research teams, who have published several studies of the association between DM and OAB. Since limited data support the effectiveness and safety of BoNT-A for treating patients with DM-associated OAB, a comprehensive evaluation of diabetic complications and urodynamic study is needed before treatment. In the future, it is imperative to explore the clinical characteristics and inflammatory biomarkers of diabetes as determining predictors of the treatment efficacy.

Detrusor contractility to parasympathetic mediators is differentially altered in the compensated and decompensated states of diabetic bladder dysfunction

Diabetic bladder dysfunction (DBD) affects up to 50% of all patients with diabetes, characterized by symptoms of both overactive and underactive bladder. Although most diabetic bladder dysfunction studies have been performed using models with type 1 diabetes, few have been performed in models of type 2 diabetes, which accounts for ~90% of all diabetic cases. In a type 2 rat model using a high-fat diet (HFD) and two low doses of streptozotocin (STZ), we examined voiding measurements and functional experiments in urothelium-denuded bladder strips to establish a timeline of disease progression. We hypothesized that overactive bladder symptoms (compensated state) would develop and progress into symptoms characterized by underactive bladder (decompensated state). Our results indicated that this model developed the compensated state at 1 wk after STZ and the decompensated state at 4 mo after STZ administration. Diabetic bladders were hypertrophied compared with control bladders. Increased volume per void and detrusor muscle contractility to exogenous addition of carbachol and ATP confirmed the development of the compensated state. This enhanced contractility to carbachol was not due to increased levels of M₃ receptor expression. Decompensation was characterized by increased volume per void, number of voids, and contractility to ATP but not carbachol. Thus, progression from the compensated to decompensated state may involve decreased contractility to muscarinic stimulation. These data suggest that the compensated state of DBD progresses temporally into the decompensated state in the male HFD/STZ model of diabetes; therefore, this male HFD/STZ model can be used to study the progression of DBD.

Therapeutic potential of intravesical injections of platelet-rich plasma in the treatment of lower urinary tract disorders due to regenerative deficiency

The bladder urothelium plays an important role of barrier function to prevent influx of urinary toxic substance and bacteria. When there is insult to the urinary bladder, the urothelium will start to regenerate on injury. However, several factors might affect the regenerative function of bladder urothelium, including aging, chronic inflammation, and system diseases such as diabetes and chronic kidney diseases (CKDs). Impairment of bladder mucosal regenerative function might result in defective urothelial cell differentiation as well as barrier function, which might be the underlying pathophysiology of interstitial cystitis/bladder pain syndrome (IC/BPS) and recurrent bacterial cystitis. Our previous immunohistochemistry (IHC) study and electron microscopic study revealed that the loss of normal umbrella cells and defective junction proteins in IC/BPS and recurrent cystitis. Platelet-rich plasma (PRP) has been previously used in many medical aspects as regenerative medicine therapy. PRP is rich in many growth factors and cytokines which modulate the process of inflammation and regeneration in the wound healing process. Recent pilot studies have shown that intravesical PRP injections improve IC symptoms and yield a success rate of 70% at 3 months after treatment. The results highly suggest that PRP injection could improve urothelial regenerative function and reduce chronic inflammation in IC patients. This article reviews recently published researches on the urothelial dysfunction biomarkers, urothelial cell differentiation, and urinary regenerative and inflammatory proteins in patients with IC/BPS or recurrent bacterial cystitis. The pathophysiology of the insufficient urothelial regeneration and differentiation; and chronic inflammation may induce urothelial dysfunction and further affect the regenerative ability of the diseased bladder urothelium in IC/BPS and recurrent bacterial cystitis are discussed.

Urothelial Senescence in the Pathophysiology of Diabetic Bladder Dysfunction-A Novel Hypothesis

Diabetic bladder dysfunction (DBD) is a well-recognized and common symptom affecting up to 50% of all diabetic patients. DBD has a broad range of clinical presentations ranging from overactive to underactive bladder symptoms that develops in middle-aged to elderly patients with long standing and poorly controlled diabetes. Low efficacy of current therapeutics and lifestyle interventions combined with high national healthcare costs highlight the need for more research into bladder dysfunction pathophysiology and novel treatment options. Cellular senescence is an age-related physiologic process in which cells undergo irreversible growth arrest induced by replicative exhaustion and damaging insults. While controlled senescence negatively regulates cell proliferation and promotes tissue regeneration, uncontrolled senescence is known to result in tissue dysfunction through enhanced secretion of inflammatory factors. This review presents previous scientific findings and current hypotheses that characterize diabetic bladder dysfunction. Further, we propose the novel hypothesis that cellular senescence within the urothelial layer of the bladder contributes to the pro-inflammatory/pro-oxidant environment and symptoms of diabetic bladder dysfunction. Our results show increased cellular senescence in the urothelial layer of the bladder; however, whether this phenomenon is the cause or effect of DBD is unknown. The urothelial layer of the bladder is made up of transitional epithelia specialized to contract and expand with demand and plays an active role in transmission by modulating afferent activity. Transition from normal functioning urothelial cells to secretory senescence cells would not only disrupt the barrier function of this layer but may result in altered signaling and sensation of bladder fullness; dysfunction of this layer is known to result in symptoms of frequency and urgency. Future DBD therapeutics may benefit from targeting and preventing early transition of urothelial cells to senescent cells.

Diabetic bladder dysfunction is associated with bladder inflammation triggered through hyperglycemia, not polyuria

Purpose

Diabetes is a grave and progressive condition characterized by debilitating complications. Diabetic bladder dysfunction (DBD) is a very common complication with no specific treatments currently available. Unlike other tissues affected by this disease, the bladder is subjected to two independent insults; 1) polyuria, created by the osmotic effects of glucose in the urine, and 2) hyperglycemia itself. Based on our understanding of inflammation as a major contributor to the underlying organ damage in several other diabetic complications, its presence in the bladder during DBD and the contribution of polyuria and hyperglycemia to its development were assessed.

Methods

Awake, restrained cystometry was performed on wild type C57BL/6 mice and diabetic (Akita) mice on a C57BL/6 background at 15 weeks of age. A subgroup of the Akita mice were treated with phlorizin, an inhibitor of sodium-glucose linked transporter types 1 and 2 that prevents glucose reabsorption in the kidney. All groups were assessed for serum glucose, 4-hour voiding totals, and inflammation in the bladder (Evans blue assay).

Results

Akita mice develop cystometrically-defined DBD by 15 weeks of age, as evidenced by an increase in urinary frequency, a decrease in voiding volume, and an increase in post-voiding residual volume. Phlorizin effectively normalized serum glucose in these animals while increasing the urine output. Inflammation in the bladder was present in the diabetic animals at this time point, but not detectable in animals receiving phlorizin.

Conclusion

Inflammation in the bladder of diabetic mice correlates with the development of DBD and is triggered by hyperglycemia, not polyuria.

Proteomic Analysis of Urothelium of Rats with Detrusor Overactivity Induced by Bladder Outlet Obstruction

Overactive bladder (OAB) syndrome is a condition that has four symptoms: urgency, urinary frequency, nocturia, and urge incontinence and negatively affects a patient's life. Recently, it is considered that the urinary bladder urothelium is closely linked to pathogenesis of OAB. However, the mechanisms of pathogenesis of OAB at the molecular level remain poorly understood, mainly because of lack of modern molecular analysis. The goal of this study is to identify a potential target protein that could act as a predictive factor for effective diagnosis and aid in the development of therapeutic strategies for the treatment of OAB syndrome. We produced OAB in a rat model and performed the first proteomic analysis on the mucosal layer (urothelium) of the bladders of sham control and OAB rats. The resulting data revealed the differential expression of 355 proteins in the bladder urothelium of OAB rats compared with sham subjects. Signaling pathway analysis revealed that the differentially expressed proteins were mainly involved in the inflammatory response and apoptosis. Our findings suggest a new target for accurate diagnosis of OAB that can provide essential information for the development of drug treatment strategies as well as establish criteria for screening patients in the clinical environment.