The role of ATP-sensitive potassium channel on acute urinary retention and subsequent catheterization in the rat

Transcutaneous electrical acupoint stimulation for prevention of postoperative urinary retention: A systematic review

Introduction

Transcutaneous electrical acupoint stimulation (TEAS) has been proposed for postoperative urinary retention (POUR). This meta-analysis evaluated the effect of TEAS in preventing POUR.

Methods

Databases were searched until February 6, 2023. Randomized controlled trials (RCTs) about TEAS for preventing POUR were included. The primary concern was the incidence of POUR, with post-void residual urine volume as a secondary outcome.

Results

Fourteen studies with 2865 participants were identified. TEAS reduced the incidence of POUR (RR = 0.44, 95%CI = 0.33 to 0.58, P < 0.00001) and decreased the post-void residual urine volume (MD = -75.41 mL, 95%CI = -118.76 to -32.06, P = 0.0007). The preventive effect on POUR was found in patients receiving anorectal, gynecologic, orthopedic and biliary surgery, but not urinary surgery. Dilatational- and continuous-wave TEAS had a great outcome in preventing POUR. Intraoperative TEAS, preoperative and intraoperative TEAS, and postoperative TEAS were beneficial, and TEAS was more beneficial when compared with sham TEAS and blank control. It is nevertheless difficult to rule out publication bias.

Conclusions

TEAS could prevent POUR. Due to insufficient evidence, multicenter, large-sample and high-quality RCTs should be conducted. (Registration:INPLASY202320095).

Molecular mechanisms of voiding dysfunction in a novel mouse model of acute urinary retention

Acute urinary retention (AUR) is a common urological emergency and affects a significant patient population. The inability to eliminate urine may lead to permanent damage to the bladder's structure and functioning. However, we know little about the underlying molecular sequelae to the urine retention. To closely mirror the potential high pressures that patients with AUR could experience, we catheterized anesthetized female mice via the urethra and filled the bladder by pumping saline (25 µL/min) into the bladder lumen to 50 cm or 80 cm water pressure. A water column with designated height (50 or 80 cm) was then adjusted to maintain constant pressure in the bladder lumen for 30 minutes. Functional and morphological evaluations were performed from 0 to 24 hours after AUR treatment. Mice exhibited incontinence and overactivity with diminished voiding pressure. Significant injury was confirmed which revealed bladders with disrupted urothelial barrier, edematous lamina propria, and distorted muscle bundles. Bladder smooth muscle (BSM) from pressure-treated mice have significantly diminished contraction force, suggesting that bladder voiding dysfunction can be attributed to impaired BSM contractility. Indeed, dysregulation of acetylcholine and purinergic signaling pathways were demonstrated, indicating that reduced efficacy of these pathways contributes to impaired BSM contractility. Finally, altered expression of β1-integrin and extracellular matrix mediated mechanotransduction pathways were detected, suggesting a profound remodeling process. These data demonstrated an easy to perform, quantifiable, and reproducible AUR mouse model, which mimics well the characteristics of human AUR patients, and our data generate new insights into the molecular mechanisms that occur following AUR.

Hypoxic conditioning in blood vessels and smooth muscle tissues: effects on function, mechanisms, and unknowns

Hypoxic preconditioning, the protective effect of brief, intermittent hypoxic or ischemic episodes on subsequent more severe hypoxic episodes, has been known for 30 yr from studies on cardiac muscle. The concept of hypoxic preconditioning has expanded; excitingly, organs beyond the heart, including the brain, liver, and kidney, also benefit. Preconditioning of vascular and visceral smooth muscles has received less attention despite their obvious importance to health. In addition, there has been no attempt to synthesize the literature in this field. Therefore, in addition to overviewing the current understanding of hypoxic conditioning, in the present review, we consider the role of blood vessels in conditioning and explore evidence for conditioning in other smooth muscles. Where possible, we have distinguished effects on myocytes from other cell types in the visceral organs. We found evidence of a pivotal role for blood vessels in conditioning and for conditioning in other smooth muscle, including the bladder, vascular myocytes, and gastrointestinal tract, and a novel response in the uterus of a hypoxic-induced force increase, which helps maintain contractions during labor. To date, however, there are insufficient data to provide a comprehensive or unifying mechanism for smooth muscles or visceral organs and the effects of conditioning on their function. This also means that no firm conclusions can be drawn as to how differences between smooth muscles in metabolic and contractile activity may contribute to conditioning. Therefore, we have suggested what may be general mechanisms of conditioning occurring in all smooth muscles and tabulated tissue-specific mechanistic findings and suggested ideas for further progress.

Role of oxidative stress and mitochondria in onset of urinary bladder dysfunction under acute urine retention

Acute urine retention is a frequent complication in patients with benign hyperplasia of the prostate gland. According to studies made on experimental animals and people, it is accompanied by the deterioration of the bladder blood supply. This study attempts to explore the relationship of intramural blood flow, production of reactive oxygen species, and functional state of the bladder detrusor in modeling of acute urine retention in rats, as well as the impact of mitochondria-targeted antioxidants (which are supposed to alleviate the effects of oxidative stress induced by experimental ischemia) on these parameters. The study showed beneficial effects of mitochondria-targeted antioxidant SkQR1 in preventing damage of the bladder caused by acute urinary retention, which suggests the therapeutic use of this type of compounds for the treatment of ischemic abnormalities of the urinary bladder.

Downregulation of TWIK-related arachidonic acid-activated K+ channel in the spinal cord of rats after complete bladder outlet obstruction

OBJECTIVES

To study the altered expression of TWIK-related arachidonic acid-activated K(+) channel in the L6-S1 spinal cord of rats after complete bladder outlet obstruction, and to investigate the role of TWIK-related arachidonic acid-activated K(+) channel in the neurogenic mechanism of bladder dysfunction.

METHODS

Female Sprague-Dawley rats were randomly divided into a complete bladder outlet obstruction group and a sham-operated control group. Cystometry was carried out and tissues of L6-S1 spinal cord were obtained for detection of TWIK-related arachidonic acid-activated K(+) channel mRNA and protein by real-time polymerase chain reaction, western blot and immunohistochemistry.

RESULTS

The bladder outlet obstruction rat model was established. Real-time polymerase chain reaction, western blot and immunohistochemistry showed that the expression of TWIK-related arachidonic acid-activated K(+) channel was lower in the L6-S1 spinal cord of the bladder outlet obstruction rats, compared with the control rats.

CONCLUSIONS

Downregulation of TWIK-related arachidonic acid-activated K(+) channel might enhance the excitability of the neurons and increase the sensitivity of the bladder, probably providing a new study model of overactive bladder secondary to bladder outlet obstruction.