Oxidative Stress and Its Relation to Lower Urinary Tract Symptoms

Sleep duration, sleep problems and developmental trajectories of urinary incontinence: a prospective cohort study

To examine if preschool sleep duration and sleep problems are associated with urinary incontinence (UI) at primary school-age. We used multinomial logistic regression to examine the association of child sleep duration/problems (3½ years) with UI trajectories (4-9 years) in 8751 (4507 boys, 4244 girls) from the Avon Longitudinal Study of Parents and Children. We adjusted for sex, socioeconomic indicators, mothers' emotional/practical/financial support, developmental delay, stressful life events, temperament, and emotional/behaviour problems. Preschool children who slept more than 8½ hours per night had a decreased probability of UI at school-age. There was a 33% reduction in odds of daytime wetting per additional hour of sleep (odds ratio [OR] = 0.67, 95% confidence interval [CI] 0.52-0.86). Sleep problems were associated with increased odds of UI e.g., getting up after being put to bed was associated with daytime wetting (OR = 2.20, 95% CI 1.43-3.39); breathing problems whilst sleeping were associated with delayed bladder control (OR = 1.68, 95% CI 1.12-2.52), and night-time waking was associated with persistent (day and night) wetting (OR = 1.53, 95% CI 1.16-2.00). Waking during the night and waking up early in the morning were associated with reduced odds of bedwetting at school-age (OR = 0.76, 95% CI 0.61-0.96 and OR = 0.80, 95% CI 0.64-0.99 respectively). Preschool children who sleep for longer have a lower likelihood of UI at school-age, whilst those with sleep problems are more likely to experience daytime wetting and combined (day and night) wetting, but not bedwetting alone. Short sleep duration and sleep problems in early childhood could be indicators of future problems attaining and maintaining bladder control.

Chronic Mealtime Shift Disturbs Metabolic and Urinary Functions in Mice: Effects of Daily Antioxidant Supplementation

PURPOSE

Through their biological clocks, organisms on this rotating planet can coordinate physiological processes according to the time of the day. However, the prevalence of circadian rhythm disorders has increased in modern society with the growing number of shift workers, elevating the risk of various diseases. In this study, we employed a mouse model to investigate the effects of urinary rhythm disturbances resulting from dietary changes commonly experienced by night shift workers.

METHODS

We established 3 groups based on feeding time and the use of restricted feeding: ad libitum, daytime, and early nighttime feeding. We then examined the urinary rhythm in each group. In addition to the bladder rhythm, we investigated changes in mRNA patterns within the tissues constituting the bladder. Additionally, we assessed the urination rhythm in Per1 and Per2 double-knockout mice and evaluated whether the injection of antioxidants modified the impact of mealtime shift on urination rhythm in wild-type mice.

RESULTS

Our study revealed that a shift in mealtime significantly impacted the circadian patterns of water intake and urinary excretion. In Per2::Luc knock-in mouse bladders cultured ex vivo, this shift increased the amplitude of Per2 oscillation and delayed its acrophases by several hours. Daily supplementation with antioxidants did not influence the mealtime shift-induced changes in circadian patterns of water intake and urinary excretion, nor did it affect the modified Per2 oscillation patterns in the cultured bladder. However, in aged mice, antioxidants partially restored the urinary rhythm.

CONCLUSION

A shift in mealtime meaningfully impacted the urination rhythm in mice, regardless of the presence of circadian clock genes.

Deletion of Nrf2 induced severe oxidative stress and apoptosis in mice model of diabetic bladder dysfunction

The nuclear factor erythroid 2-related factor 2 (Nrf2) pathway has been confirmed as a therapeutic target for type 2 diabetes mellitus (T2DM), however few studies revealed its effect in diabetic bladder dysfunction (DBD). Herein, we reported a Nrf2 deletion diabetic mouse model induced by 8-week high-fat diet feeding combined with streptozocin (STZ) injection in Nrf2 knockout mice. Besides, wild-type mice (WT) were used as control group, wild-type mice with high-fat diet feeding and STZ injection as diabetic group (WT-T2DM), and Nrf2 knockout mice as Nrf2 deletion group (KO). The pathophysiological indexes and bladder morphology showed typical pathological features of diabetic bladder dysfunction in Nrf2 knockout diabetic mouse mice (KO-T2DM). ELISA results showed that advanced glycation end products (AGEs), ROS and malondialdehyde (MDA) levels in bladder was were up-regulated in both WT-T2DM and KO-T2DM group, while superoxide dismutase (SOD) and glutathione (GSH) levels decreased in these two groups. Compared with WT-T2DM group, western blot analysis of the bladder showed down-regulated expression of NQO1 and HO-1 in KO-T2DM group. However, apoptosis, marked by Caspase3 and bax/bcl-2 ratio, was increased in KO-T2DM group. Neurotrophic factor (NGF) was significantly decreased in DBD model, and even much lower in KO-T2DM group. Collectively, our findings demonstrated that deletion of Nrf2 lead to severe oxidative stress, apoptosis, and lower level of neurotrophic factor, and provided the first set of experimental evidence, in a mouse model, to support Nrf2 as a promising target for DBD.

Methylglyoxal and Advanced Glycation End Products (AGEs): Targets for the Prevention and Treatment of Diabetes-Associated Bladder Dysfunction?

Methylglyoxal (MGO) is a highly reactive α-dicarbonyl compound formed endogenously from 3-carbon glycolytic intermediates. Methylglyoxal accumulated in plasma and urine of hyperglycemic and diabetic individuals acts as a potent peptide glycation molecule, giving rise to advanced glycation end products (AGEs) like arginine-derived hydroimidazolone (MG-H1) and carboxyethyl-lysine (CEL). Methylglyoxal-derived AGEs exert their effects mostly via activation of RAGE, a cell surface receptor that initiates multiple intracellular signaling pathways, favoring a pro-oxidant environment through NADPH oxidase activation and generation of high levels of reactive oxygen species (ROS). Diabetic bladder dysfunction is a bothersome urological complication in patients with poorly controlled diabetes mellitus and may comprise overactive bladder, urge incontinence, poor emptying, dribbling, incomplete emptying of the bladder, and urinary retention. Preclinical models of type 1 and type 2 diabetes have further confirmed the relationship between diabetes and voiding dysfunction. Interestingly, healthy mice supplemented with MGO for prolonged periods exhibit in vivo and in vitro bladder dysfunction, which is accompanied by increased AGE formation and RAGE expression, as well as by ROS overproduction in bladder tissues. Drugs reported to scavenge MGO and to inactivate AGEs like metformin, polyphenols, and alagebrium (ALT-711) have shown favorable outcomes on bladder dysfunction in diabetic obese leptin-deficient and MGO-exposed mice. Therefore, MGO, AGEs, and RAGE levels may be critically involved in the pathogenesis of bladder dysfunction in diabetic individuals. However, there are no clinical trials designed to test drugs that selectively inhibit the MGO-AGEs-RAGE signaling, aiming to reduce the manifestations of diabetes-associated bladder dysfunction. This review summarizes the current literature on the role of MGO-AGEs-RAGE-ROS axis in diabetes-associated bladder dysfunction. Drugs that directly inactivate MGO and ameliorate bladder dysfunction are also reviewed here.

Insights into the associative role of hypertension and angiotensin II receptor in lower urinary tract dysfunction

In men, the lower urinary tract comprises the urinary bladder, urethra, and prostate, and its primary functions include urine storage and voiding. Hypertension is a condition that causes multi-organ damage and an age-dependent condition. Hypertension and the renin-angiotensin system activation are associated with the development of lower urinary tract dysfunction. Hypertensive animal models show bladder dysfunction, urethral dysfunction, and prostatic hyperplasia. In the renin-angiotensin system, angiotensin II and the angiotensin II type 1 receptor, which are expressed in the lower urinary tract, have been implicated in the pathogenesis of lower urinary tract dysfunction. Moreover, among the several antihypertensives, renin-angiotensin system inhibitors have proven effective in human and animal models of lower urinary tract dysfunction. This review aimed to elucidate the hitherto known mechanisms underlying the development of lower urinary tract dysfunction in relation to hypertension and the angiotensin II/angiotensin II type 1 receptor axis and the effect of renin-angiotensin system inhibitors on lower urinary tract dysfunction. Possible mechanisms through which hypertension or activation of Ang II/AT1 receptor axis causes LUTD such as bladder dysfunction, urethral dysfunction, and prostatic hyperplasia. LUT: lower urinary tract, LUTD: lower urinary tract dysfunction, AT1: angiotensin II type 1, ACE: angiotensin-converting enzyme.

Promising therapeutic targets for the treatment of urine storage dysfunction: what's the status?

INTRODUCTION

Opinions differ on what drugs have both a rationale and a development potential for the treatment of bladder storage dysfunction.

AREAS COVERED

In the present review, the focus is given to small molecule blockers of TRP channels (TRPV1, TRPV4, TRPA1, and TRPM8), P2 × 3receptor antagonists, drugs against oxidative stress, antifibrosis agents, cyclic nucleotide - dependent pathways, and MaxiK±channel - gene therapy.

EXPERT OPINION

TRPV1 channel blockers produce hypothermia which seems to be a problem even with the most efficacious second-generation TRPV1 antagonists. This has so far precluded their application to urine storage disorders. Other TRP channel blockers with promising rationale have yet to be tested on the human lower urinary tract. The P2 × 3receptor antagonist, eliapixant, was tested in a randomized controlled clinical trial, was well tolerated but did not meet clinical efficacy endpoints. Antifibrosis agent still await application to the human lower urinary tract. New drug principles for oxidative stress, purine nucleoside phosphorylase inhibition, and NOX inhibition are still at an experimental stage, and so are soluble guanylate cyclase stimulators. Gene therapy with MaxiK±channels is still an interesting approach but no new trials seem to be in pipeline.