Autonomic dysregulation at multiple sites is implicated in age-associated underactive bladder in female mice

Age-dependent effects of the β3 adrenoceptor agonist CL316,243 on human and rat detrusor muscle strips

Motility of detrusor smooth muscle includes adrenergic relaxation and cholinergic contraction. Since the latter may be deregulated in overactive bladder (OAB) pathophysiology, anticholinergics are the standard therapy but occasionally less tolerated due to side effects such as dry mouth and constipation. β3 adrenoceptor agonists also alleviate OAB symptoms by relaxing the detrusor muscle. Their age dependence, however, is far from understood. To address this issue, we induced contractions with KCl (60 mM) and carbachol (from 10 nM to 100 μM) in the presence of the β3 adrenoceptor agonist CL316,243 (from 0.1 to 10 μM) in both human and rat muscle strips. Our results confirmed that both contractions were attenuated by β3 adrenoceptor activation in both species, but with differing age dependence. In humans, specimens from mid-life subjects showed a significantly more pronounced effect of CL316,243 in attenuating carbachol-induced contractions than those from aged subjects (Cohen's d of maximal attenuation: 1.82 in mid-life versus 0.13 in aged) without altering EC50. Conversely, attenuation of KCl responses by CL316,243 increased during ageing (Spearman correlation coefficient = -0.584, P<0.01). In rats, both KCl- and carbachol-induced contractions were significantly more attenuated by CL316,243 in samples from adolescent as compared to aged samples. Immunohistochemistry in human detrusor sections proved β3 adrenoreceptor abundance to remain unaltered during ageing. In conclusion, our findings suggest differential age-dependent changes in human β3 adrenoceptor-dependent attenuation of detrusor contraction in terms of electromechanical versus pharmacomechanical coupling; they may help understand the differential responsiveness of OAB patients to β3 agents.

The modulation of neuroinflammation by inducible nitric oxide synthase

The accumulation and propagation of misfolded proteins in the brain is a pathological hallmark shared by many neurodegenerative diseases, such as the depositions of β-amyloid and hyperphosphorylated tau proteins in Alzheimer's disease. Initial evidence shows the role of nitric oxide synthases in the development of neurodegenerative diseases. A recent, in an exciting paper (Bourgognon et al. in Proc Natl Acad Sci USA 118, 1-11, 2021. 10.1073/pnas.2009579118) it was shown that the inducible nitric oxide synthase plays an important role in promoting oxidative and nitrergic stress leading to neuroinflammation and consequently neuronal function impairments and decline in synaptic strength in mouse prion disease. In this context, we reviewed the possible mechanisms of nitric oxide synthase in the generation of neurodegenerative diseases.

Hospitalization due to mental and behavioral disorders caused by use of alcohol and psychoactive substances among older adults and elderly people in Brazil: a cross-sectional study

BACKGROUND

It has been estimated that 17% of individuals aged 50 years or older suffer from addiction to legal or illegal drugs. Use of alcohol and psychoactive substances has been correlated with several diseases, e.g. psychiatric conditions and cardiovascular and sexual dysfunctions.

OBJECTIVE

To discuss the Brazilian profile of mental and behavioral disorders caused by use of alcohol and psychoactive substances among older adults and elderly people, over the period from 2008 to 2019.

DESIGN AND SETTING

Cross-sectional study conducted among Brazilians aged 50 years or older.

METHODS

Hospitalization due to mental and behavioral disorders caused by use of alcohol and psychoactive substances was assessed through data obtained from the National Health System Department of Informatics (Departamento de Informática do Sistema Único de Saúde, DATASUS).

RESULTS

Decreasing and steady trends of hospitalization due to mental and behavioral disorders caused by use of alcohol among both men and women at all ages were observed. Similar trends were reported for all age ranges among men and women aged 60 years and older. In contrast, a slight increase was seen among women aged 50 to 59 years.

CONCLUSION

These data are crucial for qualifying mental healthcare for older adults and elderly people and for planning mental health services.

Effect of aging on lower urinary tract symptoms and urodynamic parameters in women

OBJECTIVE

Lower urinary tract symptoms (LUTS) are common in women. However, due to multifactorial etiologies, it is difficult to determine the prevalence, and functional changes with age. The aim of this study is to assess the effect of age on female LUTS, urethral and bladder function after their midlife.

MATERIALS AND METHODS

This was an observational cohort study conducted at a tertiary referral medical center. Women who visited for bothersome LUTS, valid quality of life questionnaires, and urodynamic tests were recruited into the this study. Patients The patients were divided into four groups (<50, 50-59, 60-69, and >69 years). All LUTS, and urodynamic parameters were reviewed, and compared between groups.

RESULTS

A total of 364 women were enrolled and analyzed. The urodynamic tests showed the that maximal cystometric bladder capacity, the average and maximal urine flow rate, and pressure of detrusor contractility at maximal urine flow rate were all significantly decreased with age. Besides, the voiding time, and post-voiding residual urine volume significantly increased with age. For urethral competence, the maximal urethral closure pressure deteriorated with age. All storage symptoms did not change with age, except for nocturnal enuresis. However, the effect of age on some voiding symptoms significantly increased with age, including straining to void, hesitancy, and intermittency.

CONCLUSIONS

Lower urinary tract symptoms, bladder and urethral functions change with age, particularly voiding function. Physicians should be aware of the aging process when counseling and before implementing management strategies, particularly for older people.

High percentage of neurologic deficits in the electrophysiology study of the lower urinary tract in patients with detrusor underactivity and chronic urinary retention

OBJECTIVES

Both detrusor underactivity (DU) and bladder outlet obstruction are the common causes of chronic urinary retention. Some novel treatment approaches focus on modulating micturition reflex and external urethral sphincter (EUS) function. This study used electrophysiologic (EP) studies to investigate the micturition reflex and EUS conditions of chronic urinary retention patients.

METHODS

Sixty patients with urodynamic DU and chronic urinary retention were studied using (1) bulbocavernous reflex (BCR) by electric stimulation, (2) electromyography (EMG) of the EUS, and (3) nerve conduction velocity (NCV) studies of the pudendal nerve. The EP findings were analyzed in DU patients with different etiologies.

RESULTS

The BCR was positive in 41.7% of patients. In EMG studies, denervation, reinnervation, and reduced recruitment of the EUS were observed in 21.7%, 71.7%, and 88.3% patients, respectively. Decreased amplitude of pudendal nerve conduction in NCV studies was noted in 73.3% of patients. Patients with sacral neuropathy had a lower BCR positive rate (p = 0.001), a nonsignificant but higher denervation rate (p = 0.059) in EMG studies, and a higher rate of decreased amplitude in NCV (p = 0.011) than those without sacral neuropathy. Excluding patients with sacral neuropathy or diabetes mellitus, a high percentage of neurologic deficits was still detected in EP studies.

CONCLUSIONS

Chronic urinary retention patients with urodynamic DU not only have bladder dysfunction, but also potential neuropathy in the sacral reflexes, pudendal nerve, or urethral sphincter innervation. The neurologic deficits explored in EP studies may affect the decision-making around the therapy to restore the voiding function in DU.

Transient receptor potential channels in sensory mechanisms of the lower urinary tract

Disruptions to sensory pathways in the lower urinary tract commonly occur and can give rise to lower urinary tract symptoms (LUTS). The unmet clinical need for treatment of LUTS has stimulated research into the molecular mechanisms that underlie neuronal control of the bladder and transient receptor potential (TRP) channels have emerged as key regulators of the sensory processes that regulate bladder function. TRP channels function as molecular sensors in urothelial cells and afferent nerve fibres and can be considered the origin of bladder sensations. TRP channels in the lower urinary tract contribute to the generation of normal and abnormal bladder sensations through a variety of mechanisms, and have demonstrated potential as targets for the treatment of LUTS in functional disorders of the lower urinary tract.

The basal release of endothelium-derived catecholamines regulates the contractions of Chelonoidis carbonaria aorta caused by electrical-field stimulation

The contractions of Chelonoidis carbonaria aortic rings induced by electrical field stimulation (EFS) are not inhibited by blockade of the voltage-gated sodium channels by tetrodotoxin but almost abolished by the α1/α2-adrenoceptor antagonist phentolamine. The objective of this study was to identify the mediator(s) responsible for the EFS-induced contractions of Chelonoidis carbonaria aortic rings. Each ring was suspended between two wire hooks and mounted in isolated 10 ml organ chambers filled with oxygenated and heated Krebs-Henseleit's solution. Dopamine, noradrenaline and adrenaline concentrations were analysed by liquid chromatography coupled to tandem mass spectrometry. The contractions caused by dopamine and EFS were done in absence and presence of the nitric oxide (NO) synthesis inhibitor L-NAME, the NO-sensitive guanylyl cyclase inhibitor ODQ, the D1-like receptor antagonist SCH-23390, the D2-like receptor antagonists risperidone, quetiapine, haloperidol, and the tyrosine hydroxylase inhibitors salsolinol and 3-iodo-L-tyrosine. Basal concentrations of dopamine, noradrenaline and adrenaline were detected in Krebs-Henseleit solution containing the aortic rings. The catecholamine concentrations were significantly reduced in endothelium-denuded aortic rings. L-NAME and ODQ significantly potentiated the dopamine-induced contractions. The D2-like receptor antagonists inhibited the EFS-induced contractions of the aortic rings treated with L-NAME, whereas SCH 23390 had no effect. Similar results were observed in the contractions induced by dopamine in L-NAME treated aortic rings. These results indicate that catecholamines released by endothelium regulate the EFS-induced contractions. This may constitute a suitable mechanism by which reptilia modulate specific organ blood flow distribution.

This paper has an associated First Person interview with the first author of the article.

Summary:Chelonoidis carbonaria aortic rings release endothelium-derived catecholamines that modulate vascular smooth muscle reactivity.

Emerging roles of the TRPV4 channel in bladder physiology and dysfunction

The transient receptor potential vanilloid type 4, TRPV4, is a polymodal cation channel which can be activated by diverse stimuli including mechanical, thermal and chemical cues. In the urinary bladder, TRPV4 is not only abundantly expressed in the urothelium but may also be localized in subepithelium, detrusor smooth muscles and afferent neurons. Emerging evidence indicates that the TRPV4 channel plays a sensory role in the uroepithelium, where it may regulate the release of sensory mediators such as ATP, which in turn modulates afferent nerve activity in response to bladder filling during the urination cycle. TRPV4 may also directly regulate detrusor contractility and the urothelial barrier function. Altered TRPV4 expression has been detected in various pathological bladder conditions. As such, TRPV4 may be a promising therapeutic target for bladder dysfunctions.

Stretch- and carbachol-induced ATP release from bladder wall preparations of young and aged mice

AIMS

Bladder wall stretch increases tissue tension and releases adenosine 5'-triphosphate (ATP) as part of a transduction process to sense bladder filling. Aging is associated with bladder fibrosis to produce a stiffer bladder wall: this may augment ATP release and contribute to age-dependent urgency. Muscarinic agonists also release ATP and present a potential target for antimuscarinic agents, but its age-dependency is unknown. This study aimed, in young and old mice, to: (a) quantify the relationship between bladder wall stiffness and stretch-dependent ATP release and; (b) characterize muscarinic agonist-dependent release.

METHODS

ATP release from young (9-12 weeks) and aged (24 months) mouse bladder wall was measured in vitro, with a luciferin-luciferase assay, after stretch or carbachol exposure. Bladder wall stiffness, measured simultaneously during stretch, was compared to histological proportions of connective tissue and detrusor muscle.

RESULTS

With young mice, stretch-activated ATP release required an intact mucosa and was positively associated with wall stiffness. ATP release by carbachol was about four-fold greater compared to stretch. With aged mice: ATP release varied a hundred-fold and no association with stiffness; carbachol release diminished; connective tissue and mucosa thickness increased.

CONCLUSIONS

With young mice, stretch, or muscarinic agonists potently induce bladder wall ATP release. Stretch-dependent release is proportional to bladder wall stiffness, independent of the extent of stretch. With aged mice dependence of stretch-activated ATP release with stiffness was lost. The huge variability of release suggests that aged mice do not form a homogenous cohort and may underlie the heterogeneity in bladder filling sensations.

Detrusor Underactivity and Underactive Bladder in Women: What Is New?

Purpose of Review

Detrusor underactivity (DU) and its symptom-based correlation, the underactive bladder (UAB), are common problems encountered in urological practice. Whilst DU has been defined for many years, only recently has UAB received a formal definition and there is now accumulating literature based on this condition. In this article, we reviewed the recent literature on the aetiology, pathogenesis, diagnosis and management of DU/UAB in women.

Recent Findings

Detrusor underactivity is diagnosed on urodynamic studies but there still remains a lack of widely recognised and accepted diagnostic criteria. Commencing treatment based on the diagnosis of UAB, with or without a PVR measurement, is perhaps feasible due to the lower occurrence of BOO in women and specific clinical features that may distinguish this group. Prospective studies attempting to correlate UAB with the underlying DU are needed before this approach could be considered.

Summary

Detrusor underactivity/UAB in women requires a separate consideration from men due to the anatomical and functional differences in the lower urinary tracts between both genders and consequent differences in pathologies affecting them. The aetiology of DU remains largely unknown, but is probably multifactorial, including myogenic, neurogenic and vasculogenic factors. There remains a lack of any simple effective drug treatments, whilst apart from sacral neuromodulation for the specific subgroup with non-obstructive urinary retention, no safe and effective surgical treatment is currently available. Often, permanent or intermittent bladder drainage with a catheter is the final solution.