Can we define and characterize the aging lower urinary tract?-ICI-RS 2015

Lower urinary tract symptoms and functional ability in older adults: a community-based cross-sectional study

OBJECTIVES

Functional ability, or the ability to live actively in older age, is essential for healthy ageing. This study assessed the association between the five types of lower urinary tract symptoms (LUTS) and functional ability among community-dwelling older adults (≥65 years old).

DESIGN

A cross-sectional study.

SETTING

Community-dwelling older adults (≥65 years old) randomly selected from the basic resident register of Kashiwa city as part of the Kashiwa study.

PARTICIPANTS

The study included 916 community-dwelling older adults (481 male participants) in Japan.

OUTCOME MEASURES

A self-administered questionnaire was used to collect data regarding LUTS, which included frequency, nocturia, urgency, urinary incontinence and overactive bladder (OAB). Functional ability was measured using the Japan Science and Technology Agency Index of Competence. Sex-stratified logistic regression analyses were conducted, adjusting age, obesity, alcohol consumption, polypharmacy and comorbidities.

RESULTS

Male participants experienced symptoms of frequency, nocturia, urgency, urinary incontinence and OAB at rates of 68.0%, 89.0%, 16.0%, 3.7% and 4.3%, respectively. Female participants experienced these symptoms at rates of 68.3%, 80.0%, 11.0%, 7.4% and 8.5%, respectively. Among male participants, lower functional ability was only associated with nocturia (≥3 times/night) (adjusted OR (AOR): 1.71, 95% CI 1.05 to 2.79). Contrarily, lower functional ability among female participants was significantly associated with frequency (AOR: 1.61, 95% CI 1.04 to 2.49), urgency (AOR: 2.06, 95% CI 1.08 to 3.95) and OAB (AOR: 2.43, 95% CI 1.15 to 5.11).

CONCLUSION

The different associations between LUTS and functional ability by sex might be related to differences in the effect of comorbidities and physical fatigue. Our results help clarify the multifaceted effects of LUTS in old age, the need for early detection and treatment of LUTS, and the importance of maintaining functional ability.

Oxidative Stress: A Putative Link Between Lower Urinary Tract Symptoms and Aging and Major Chronic Diseases

Aging and major chronic diseases are risk factors for lower urinary tract symptoms (LUTS). On the other hand, oxidative stress (OS) is one of the fundamental mechanisms of aging and the development of chronic diseases. Therefore, OS might be a candidate mechanism linking these two clinical entities. This article aims to summarize the studies on the prevalence of LUTS, the role of OS in aging and chronic diseases, and the potential mechanisms supporting the putative link. A comprehensive literature search was performed to identify recent reports investigating LUTS and OS in major chronic diseases. In addition, studies on the impact of OS on the lower urinary tract, including bladder, urethra, and prostate, were collected and summarized. Many studies showed LUTS are prevalent in aging and major chronic diseases, including obesity, metabolic syndrome, diabetes, cardiovascular disease, hypertension, obstructive sleep apnea, autoimmune diseases, Alzheimer’s disease, and Parkinson’s disease. At the same time, OS is a key component in the pathogenesis of those chronic diseases and conditions. Recent studies also provided evidence that exacerbated OS can cause functional and/or structural changes in the bladder, urethra, and prostate, leading to LUTS. The reviewed data support the concept that OS is involved in multiple risk factors-associated LUTS, although further studies are needed to confirm the causative relationship. The specific ROS/RNS and corresponding reactions/pathways involved in chronic diseases and associated LUTS should be identified in the future and could serve as therapeutic targets.

Oxidative Stress Biomarkers in Age-Related Lower Urinary Tract Disorders: A Systematic Review

PURPOSE

To conduct a systematic review of preclinical and clinical peer-reviewed evidence linking alterations in oxidative stress biomarkers or outcome measures that were also prevalent in specific age-related lower urinary tract (LUT) disorders.

METHODS

PubMed, Scopus, CINAHL, and Embase were searched for peer-reviewed studies published between January 2000 and March 2021. Animal and human studies that reported on the impact of oxidative stress in age-related LUT disorders through structural or functional changes in the LUT and changes in biomarkers were included. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) protocol was followed.

RESULTS

Of 882 articles identified, 21 studies (13 animal; 8 human) met inclusion criteria. Across LUT disorders, common structural changes were increased bladder and prostate weights, ischemic damage, nerve damage and detrusor muscle hypertrophy; common functional changes included decreased bladder contraction, increased bladder sensation and excitability, decreased perfusion, and increased inflammation. The disorders were associated with increased levels of biomarkers of oxidative stress that provided evidence of either molecular damage, protective mechanisms against oxidative stress, neural changes, or inflammation. In all cases, the effect on biomarkers and enzymes was greater in aged groups compared to younger groups.

CONCLUSION

Increased oxidative stress, often associated with mitochondrial dysfunction, plays a significant role in the pathogenesis of age-related LUT disorders and may explain their increasing prevalence. This systematic review identifies potential markers of disease progression and treatment opportunities; further research is warranted to evaluate these markers and the mechanisms by which these changes may lead to age-related LUT disorders.

Transition from Childhood Nocturnal Enuresis to Adult Nocturia: A Systematic Review and Meta-Analysis

Purpose

Current literature has suggested a relationship between nocturnal enuresis (NE) in childhood and the development of nocturia later in life as both disorders have similar underlying etiologies, comorbidities, and treatments. The objective was to synthesize the available evidence on the association between childhood NE and later presentation of nocturia.

Methods

PubMed, CINAHL, Scopus, and Google Scholar were searched for peer-reviewed studies published between January 1980 and April 2021. Case–control and cohort studies that reported on childhood NE and current nocturia were included. The PRISMA protocol was followed (PROSPERO ID: CRD42021256255). A random-effects model was applied to calculate the pooled odds ratio (OR) and 95% confidence interval (CI). Risk of bias was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) criteria and with a funnel plot.

Results

Of the 278 articles identified, 8 studies met inclusion criteria. The 6 case–control and 2 prospective cohort studies resulted in a total sample size of 26,070 participants. In a random-effect pooled analysis, childhood NE was significantly associated with the development of nocturia (OR: 1.75, 95% CI: 1.11–2.40). Significant heterogeneity (I² = 92.7%, p < 0.01) was identified among the included studies, which was reflected in an asymmetrical funnel plot. NE and nocturia have similar underlying etiologies of hormonal abnormalities, sleep disorders, physiological disorders, and psychological disorders.

Conclusion

The history of childhood NE is significantly associated with nocturia later in life. The data in this meta-analysis support this transition and identify potential similarities between the two disorders. The sparse number of articles relevant to this topic is a strong indicator of the need for more work on this transition from childhood to maturity. More studies are warranted to further explore the association between NE and nocturia.

ATP as a cotransmitter in sympathetic and parasympathetic nerves - another Burnstock legacy

Geoff Burnstock created an outstanding scientific legacy that includes identification of adenosine 5'-triphosphate (ATP) as an inhibitory neurotransmitter in the gut, the discovery and characterisation of a large family of purine and uridine nucleotide-sensitive ionotropic P2X and metabotropic P2Y receptors and the demonstration that ATP is as an excitatory cotransmitter in autonomic nerves. The evidence for cotransmission includes that: 1) ATP is costored with noradrenaline in synaptic vesicles in postganglionic sympathetic nerves innervating smooth muscle tissues, including the vas deferens and most arteries. 2) When coreleased with noradrenaline, ATP acts at postjunctional P2X1 receptors to elicit depolarisation, Ca²⁺ influx, Ca²⁺ sensitisation and contraction. 3) ATP is also coreleased with acetylcholine from postganglionic parasympathetic nerves innervating the urinary bladder, where it stimulates postjunctional P2X1 receptors, and a second, as yet unidentified site to evoke contraction of detrusor smooth muscle. In both systems membrane-bound ecto-enzymes and soluble nucleotidases released from postganglionic nerves dephosphorylate ATP and so terminate its neurotransmitter actions. Currently, the most promising potential area of therapeutic application relating to cotransmission is treatment of dysfunctional urinary bladder. This family of disorders is associated with the appearance of a purinergic component of neurogenic contractions. This component is an attractive target for drug development and targeting it may be a rewarding area of research.

Age-dependent histomorphometric evolution of the corpus spongiosum

Purpose:

To quantify the age-dependent changes in the relative volume of elastic fibers, collagen fibers and the proportion of collagen types I/III in the corpus spongiosum of rats.

Methods:

Forty-eight rats, raised under similar conditions, were divided into four groups (G1 to G4) and underwent penectomy at the ages of 6, 9, 12 and 24 months, respectively. Histological sections from the middle segment of the penis were stained with Weigert’s resorcin-fuchsin, Masson’s trichrome and Picrosirius red, the volumetric density of elastic fibers, collagen fibers and the proportion of collagen types I and III in the corpus spongiosum were determined by stereological analysis.

Results:

A reduction in the proportion of collagen I/III between the groups G3 and G4 (p < 0.048) was observed. In the volumetric analysis of elastic fiber, we observed a significant rise between the groups G2 and G3 (p < 0.03) and a reduction of the volume between the groups G3 and G4 (p < 0.01). However, there was no difference in the quantity of total collagen between the groups (p > 0.54).

Conclusions:

Aging in rats did not change the quantity of total collagen but reduced the proportion of collagen types I/III and the volume of elastic fibers.

Functional brain imaging in voiding dysfunction

Purpose of review

Voiding dysfunction (VD) is morbid, costly, and leads to urinary tract infections, stones, sepsis, and permanent renal failure. Evaluation and diagnosis of VD in non-obstructed patients can be challenging. Potential diagnostic and therapeutic options beyond the bladder, such as brain centers involved in voiding have been proposed as promising targets. This review focuses on current and future applications of functional neuroimaging in human in voiding and in patients with VD.

Recent findings

The current understanding of brain centers, and their roles in initiating, maintaining and/or modulating voiding, is rudimentary in humans and in patients with VD. With the advent and advancement in functional neuroimaging we are gaining more insight into specific brain regions involved in the voiding phase of micturition. In healthy individuals, right dorsomedial pontine tegmentum, periaqueductal grey, hypothalamus, and the inferior, medial and superior frontal gyrus have been identified as regions of interest in voiding.

Summary

Functional neuroimaging could suggest new diagnostic methods and provides crucial steps towards therapeutic options for the morbid and intractable VD condition, in patients with neurogenic (e.g. MS or Strokes) or non-neurogenic VD (e.g. underactive bladder or Fowler's syndrome).

The aging bladder phenotype is not the direct consequence of bladder aging

AIMS

The prevalence of urinary dysfunction increases with age, yet therapies are often suboptimal. Incomplete understanding of the linkages between system, organ, and tissue domains across lifespan remains a knowledge gap. If tissue-level changes drive the aging bladder phenotype, parallel changes should be observed across these domains. In contrast, a lack of inter-domain correlation across age groups would support the hypothesis that urinary performance is a measure of the physiologic reserve, dependent on centrally-mediated adaptive mechanisms in the aging system.

METHODS

Male and female mice across four age groups underwent sequential voiding spot assays, pressure/flow cystometry, bladder strip tension studies, histology, and quantitative PCR analyses. The primary objective of this study was to test the impact of age on the cortical, autonomic, tissue functional and structural, and molecular domains, and identify inter-domain correlations among variables showing significant changes with age within these domains.

RESULTS

Behavior revealed diminished peripheral voiding and spot size in aged females. Cystometry demonstrated increased postvoid residual and loss of volume sensitivity, but the preservation of voiding contraction power, with almost half of oldest-old mice failing under cystometric stress. Strip studies revealed no significant differences in adrenergic, cholinergic, or EFS sensitivity. Histology showed increased detrusor and lamina propria thickness, without a change in collagen/muscle ratio. Adrb2 gene expression decreased with age. No consistent inter-domain correlations were found across age groups.

CONCLUSIONS

Our findings are consistent with a model in which centrally-mediated adaptive failures to aging stressors are more influential over the aging bladder phenotype than local tissue changes.

NLRP3/IL1β inflammasome associated with the aging bladder triggers bladder dysfunction in female rats

Bladder dysfunction is associated with fibrosis-mediated aging, but the corresponding mechanism remains to be elucidated. Activation of the NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome is related to chronic diseases associated with aging, including organ fibrosis. The present study aimed to explore the role of NLRP3/interleukin 1β in aging-associated bladder dysfunction. Female Sprague-Dawley rats were divided into the following two groups (n=10 rats/group): 2-month-old group (young group) and 24-month-old group (old group). Urodynamics were performed to assess the bladder function of the rats. The histological alterations were identified using Masson's trichrome staining. The protein expression of the NLRP3 inflammasome and NAD-dependent protein deacetylase sirtuin-3, mitochondrial (SIRT3) were detected by western blot analysis, and immunohistochemistry was used to examine a senescence marker (p21) and the NLRP3 inflammasome in the bladder. The localization of the key molecule Caspase1 was determined using immunofluorescence. The voiding time was longer in the old group compared with the young group. The expression levels of SIRT3 were reduced in the bladders of the old group, while those of the NLRP3 inflammasome and the senescence marker were significantly higher in the bladders of the old group compared with the young group. Increased collagen deposition leads to chronic bladder fibrosis with increased NLRP3. In the histological examination, the bladders of the old group displayed increased collagen deposition, urothelial thinning and detrusor shrinkage compared with the young group. Tissue fibrosis and urothelial alterations are the principal causes of bladder dysfunction during aging. Downregulated SIRT3 and upregulated expression of the NLRP3 inflammasome are involved in the degradation of aging bladders. Inflamm-aging is a novel mechanism underlying bladder dysfunction.