Chronobiology of Micturition: Putative Role of the Circadian Clock

How should we assess the cardiovascular system in patients presenting with bothersome nocturia? ICI-RS 2023

AIMS

The link between nocturia and cardiovascular disease (CVD) is frequently discussed in literature, yet the precise nature of this relationship remains poorly characterized. The existing literature was reviewed in order to address issues concerning the origin, diagnosis, management, and implications of the co-occurrence of CVD and nocturia.

METHODS

This review summarizes literature and recommendations regarding the link between CVD and nocturia discussed during a think-tank meeting held at the 2023 International Consultation on Incontinence-Research Society.

RESULTS

Cardiovascular disorders are often underestimated contributors to nocturia, with various potential mechanisms influencing nighttime urination, such as impact on fluid retention, atrial natriuretic peptide, and glomerular filtration rate. The redistribution of fluid from leg edema in supine position can lead nocturnal polyuria (NP). Additionally, sleep disturbances due to nocturia in itself may lead to CVD through an increase in blood pressure, insulin resistance, and inflammation. Disrupted circadian rhythms (e.g., in sleep pattern and urine production) were identified as critical factors in most etiologies of nocturia, and their contribution is deemed imperative in future research and treatment approaches, particularly in the aging population. NP can be detected through a simple bladder diary and can even be used to distinguish cardiac from noncardiac causes of nocturia. For the treatment of NP, desmopressin can be effective in select patients, however, caution and close monitoring is warranted for those with CVD due to increased risk of side effects.

CONCLUSIONS

Gaps were identified in the available evidence and clear cut recommendations were put forth for future research. It is essential to gain a deeper understanding of the mechanisms linking nocturia and CVD to develop optimal management strategies.

Nocturnal urination is associated with the presence of higher ventilatory chemosensitivity in patients with obstructive sleep apnea

PURPOSE

Chemosensitivity is an essential part of the pathophysiological mechanisms of obstructive sleep apnea (OSA). This study aims to use the rebreathing method to assess hypercapnic ventilatory response (HCVR) and analyze the association between chemosensitivity and certain symptoms in patients with OSA.

METHODS

A total of 104 male patients with diagnosed OSA were enrolled. The HCVR was assessed using rebreathing methods under hypoxia exposure to reflect the overall chemosensitivity. Univariate and multivariate linear regression were used to explore the association with chemosensitivity. Participants were enrolled in the cluster analysis using certain symptoms, basic characteristics, and polysomnographic indices.

RESULTS

At similar baseline values, the high chemosensitivity group (n = 39) demonstrated more severe levels of OSA and nocturnal hypoxia than the low chemosensitivity group (n = 65). After screening the possible associated factors, nocturnal urination, rather than OSA severity, was found to be positively associated with the level of chemosensitivity. Cluster analysis revealed three distinct groups: Cluster 1 (n = 32, 34.0%) held younger, obese individuals with nocturnal urination, elevated chemosensitivity level, and very severe OSA; Cluster 2 (41, 43.6%) included middle-aged overweighted patients with nocturnal urination, increased chemosensitivity level, but moderate-severe OSA; and Cluster 3 (n = 21, 22.3%) contained middle-aged overweighted patients without nocturnal urination, with a lowered chemosensitivity level and only moderate OSA.

CONCLUSION

The presence of nocturnal urination in male patients with OSA may be a sign of higher levels of ventilatory chemosensitivity, requiring early therapy efforts independent of AHI levels.

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.

Nocturia and obstructive sleep apnoea

Nocturia, the need to urinate at night, is a common symptom in patients with obstructive sleep apnoea (OSA). Continuous positive airway pressure treatment can reduce nocturia in some patients, but the underlying mechanisms are complex and not fully understood. OSA affects the autonomic nervous system, oxidative stress and endothelial damage. Furthermore, the commonly held theory attributing polyuria to a false signal of cardiac overload and response natriuresis has limitations. A comprehensive approach to the management of nocturia in OSA, considering factors such as comorbidities, medication use, alcohol consumption and lifestyle, is needed. Effective management of nocturia in OSA requires a multidisciplinary approach, and urologists should be aware of the potential effect of OSA on physiology and refer patients for further testing at a sleep centre. In addition to continuous positive airway pressure, other interventions such as oral appliances and surgical obstruction treatment could be beneficial for some patients. Overall, understanding the complex interplay between OSA and nocturia is crucial for optimizing patient outcomes.

Link between circadian rhythm and benign prostatic hyperplasia (BPH)/lower urinary tract symptoms (LUTS)

BACKGROUND

Benign prostatic hyperplasia (BPH) is the most common urologic disease in aging males, affecting 50% of men over 50 and up to 80% of men over 80 years old. Its negative impact on health-related quality of life implores further investigation into its risk factors and strategies for effective management. Although the exact molecular mechanisms underlying pathophysiological onset of BPH are poorly defined, the current hypothesized contributors to BPH and lower urinary tract symptoms (LUTS) include aging, inflammation, metabolic syndrome, and hormonal changes. These processes are indirectly influenced by circadian rhythm disruption. In this article, we review the recent evidence on the potential association of light changes/circadian rhythm disruption and the onset of BPH and impact on treatment.

METHODS

A narrative literature review was conducted using PubMed and Google Scholar to identify supporting evidence. The articles referenced ranged from 1975 to 2023.

RESULTS

A clear relationship between BPH/LUTS and circadian rhythm disruption is yet to be established. However, common mediators influence both diseases, including proinflammatory states, metabolic syndrome, and hormonal regulation that can be asserted to circadian disruption. Some studies have identified a possible relationship between general LUTS and sleep disturbance, but little research has been done on the medical management of these diseases and how circadian rhythm disruption further affects treatment outcomes.

CONCLUSIONS

There is evidence to implicate a relationship between BPH/LUTS and circadian rhythm disruptions. However, there is scarce literature on potential specific link in medical management of the disease and treatment outcomes with circadian rhythm disruption. Further study is warranted to provide BPH patients with insights into circadian rhythm directed appropriate interventions.

Healthy sleep practices for shift workers: consensus sleep hygiene guidelines using a Delphi methodology

STUDY OBJECTIVES

The unique requirements of shift work, such as sleeping and working at variable times, mean that current sleep hygiene guidelines may be inappropriate for shift workers. Current guidelines may also contradict fatigue management advice (e.g. advising against daytime napping). The present study utilized a Delphi methodology to determine expert opinion regarding the applicability of current guidelines for shift workers, the appropriateness of the term "sleep hygiene," and develop tailored guidelines for shift workers.

METHODS

The research team reviewed current guidelines and existing evidence to draft tailored guidelines. Seventeen individual guidelines, covering sleep scheduling, napping, sleep environment, bedtime routine, substances, light exposure, diet, and exercise were drafted. Experts from sleep, shift work, and occupational health fields (n = 155) were invited to review the draft guidelines using a Delphi methodology. In each round, experts voted on individual guidelines, with 70% agreement considered consensus. Where consensus was not reached, written feedback from experts was discussed and incorporated into subsequent iterations.

RESULTS

Of the experts invited, 68 (44%) agreed to participate, with 55 (35%) completing the third (final) round. Most experts (84%) agreed that tailored guidelines were required for shift workers. Consensus was reached on all guidelines after three rounds. One additional guideline (sleep inertia) and an introductory statement were developed, resulting in a final set of 18 individual guidelines, termed "healthy sleep practices for shift workers."

CONCLUSIONS

This is the first study to develop tailored sleep hygiene guidelines for shift workers. Future research should investigate the acceptability and effectiveness of these guidelines amongst shift workers.

Diurnal differences in urine flow in healthy young men in a light-controlled environment: a randomized crossover design

BACKGROUND

Older men often experience nocturnal urination difficulties, reflected by diurnal differences in maximum urine flow (Qmax). Since lower urinary tract symptoms and pathological comorbidities are frequent in older men, it remains unclear whether this diurnal variation is a physiological or pathological phenomenon. Our aim was to quantify the diurnal variability of Qmax in healthy young participants under varying daylight conditions in a stable environment to discern potential underlying causes of nocturnal urination difficulties.

METHODS

Twenty-one healthy young men were recruited in a 4-day study utilizing daytime (08:00-18:00) exposure with two light conditions in randomized order: dim (< 50 lx) or bright (~2500 lx). Day 1 was for acclimation, and urine flow was assessed from day 2. The participants urinated ad libitum during day 2 and then at fixed 3-4-h intervals thereafter (days 3-4). Regular urination Qmax at late night (04:00) on day 4 was compared with the nearest voided volume during daytime of day 3 (mDay).

RESULTS

Morning Qmax scores (after bed-11:00) on day 2 were significantly lower than evening (17:00-before pre-sleep) in bright conditions and those of daytime (11:00-17:00), evening (17:00-before pre-sleep), and pre-sleep in dim conditions. Pre-sleep Qmax during the ad libitum period was significantly higher in dim than bright conditions. Late-night Qmax values (04:00) on day 4 were significantly lower than Qmax scores of mDay on day 3 in both light conditions.

CONCLUSIONS

Healthy young men had a clear diurnal Qmax difference that decreased during late night and morning. In addition, the pre-sleep Qmax values in dim daylight were significantly higher than in bright daylight. Taken together, we conclude that late-night and morning decreases in Qmax are an instinctive physiological phenomenon in humans, and the diurnal difference of Qmax can be influenced by daylight conditions.

Risk analyses of nocturia on incident poor sleep and vice versa: the Nagahama study

Cross-sectional relationships between nocturia and sleep problems have been well evaluated but the risk association for each incidence is scarcely reported. This analysis included 8076 participants of the Nagahama study in Japan (median age 57, 31.0% male) and associations between nocturia and self-reported, sleep-related problems (poor sleep) were evaluated cross-sectionally. Causal effects on each new-onset case were analyzed longitudinally after 5 years. Three models were applied: univariable analysis, adjustment for basic variables (i.e., demographic and lifestyle variables) and full adjustment for basic and clinical variables. The overall prevalences of poor sleep and nocturia were 18.6% and 15.5%, while poor sleep was positively associated with nocturia (OR = 1.85, p < 0.001) and vice versa (OR = 1.90, p < 0.001). Among 6579 good sleep participants, 18.5% developed poor sleep. Baseline nocturia was positively associated with this incident poor sleep (OR = 1.49, p < 0.001, full adjustment). Among 6824 non-nocturia participants, the nocturia incidence was 11.3%. Baseline poor sleep was positively associated with this incident nocturia (OR = 1.26, p = 0.026); such associations were significant only in women (OR = 1.44, p = 0.004) and under-50-year-old groups (OR = 2.82, p < 0.001), after full adjustment. Nocturia and poor sleep associate with each other. Baseline nocturia can induce new-onset poor sleep while baseline poor sleep may induce new-onset nocturia only in women.

Effectiveness and Safety of a Mixture of Nobiletin and Tangeretin in Nocturia Patients: A Randomized, Placebo-Controlled, Double-Blind, Crossover Study

Nobiletin and tangeretin (NoT) are flavonoids derived from the peel of Citrus depressa, and they have been found to modulate circadian rhythms. Because nocturia can be considered a circadian rhythm disorder, we investigated the efficacy of NoT for treating nocturia. A randomized, placebo-controlled, double-blind, crossover study was conducted. The trial was registered with the Japan Registry of Clinical Trials (jRCTs051180071). Nocturia patients aged ≥50 years who presented nocturia more than 2 times on a frequency-volume chart were recruited. Participants received NoT or a placebo (50 mg once daily for 6 weeks), followed by a washout period of ≥2 weeks. The placebo and NoT conditions were then switched. Changes in nocturnal bladder capacity (NBC) were the primary endpoint, and changes in nighttime frequency and nocturnal polyuria index (NPi) were secondary endpoints. Forty patients (13 women) with an average age of 73.5 years were recruited for the study. Thirty-six completed the study, while four withdrew. No adverse events directly related to NoT were observed. NoT had little effect on NBC compared with the placebo. In contrast, NoT significantly changed nighttime frequency by -0.5 voids compared with the placebo (p = 0.040). The change in NPi from baseline to the end of NoT was significant (-2.8%, p = 0.048). In conclusion, NoT showed little change in NBC but resulted in decreased nighttime frequency with a tendency toward reduced NPi.

Role of circadian rhythms and melatonin in bladder function in heath and diseases

The circadian system modulates all visceral organ physiological processes including urine storage and voiding. The "master clock" of the circadian system lies within suprachiasmatic nucleus of the hypothalamus while "peripheral clocks" are found in most peripheral tissue and organs, including the urinary bladder. Disruptions of circadian rhythms can cause organ malfunction and disorder or exacerbate pre-existing ones. It has been suggested that nocturia, which develops mostly in the elderly, could be a circadian-related disorder of the bladder. In the bladder, many types of gap junctions and ion channels in the detrusor, urothelium and sensory nerves are likely under strict local peripheral circadian control. The pineal hormone, melatonin, is a circadian rhythm synchroniser capable of controlling a variety of physiological processes in the body. Melatonin predominantly acts via the melatonin 1 and melatonin 2 G-protein coupled receptors expressed in the central nervous system, and many peripheral organs and tissues. Melatonin could be beneficial in the treatment of nocturia and other common bladder disorders. The ameliorating action of melatonin on bladder function is likely due to multiple mechanisms which include central effects on voiding and peripheral effects on the detrusor and bladder afferents. More studies are warranted to determine the precise mechanisms of circadian rhythm coordination of the bladder function and melatonin influences on the bladder in health and diseases.

Effectiveness of melatonin for the treatment of nocturia: a randomized controlled trial

INTRODUCTION AND HYPOTHESIS

Nocturia affects health and quality of life (QoL). Current medical treatments can cause severe adverse effects, especially when treating elderly patients. Endogenous melatonin has a physiologic role in urinary bladder function, and the exogenous one may be beneficial for this condition. This article aims to evaluate the effectiveness and safety of melatonin for ameliorating nocturia in older women.

METHODS

This randomized, double-blind, placebo-controlled trial was conducted at a university hospital in Thailand. Sixty women with nocturia, aged > 55 years, were prospectively recruited and were later randomly allocated to treatment (melatonin 2 mg/day, n = 30) and control (placebo, n = 30) arms for 2 weeks. Outcome measures included nocturia episodes, nocturia-related parameters, Nocturia Quality of Life Questionnaire (N-QoL) scores, and adverse events.

RESULTS

The treatment and control groups were comparable in mean age (65.9 + 7.5 vs. 68.5 + 6.3 years). Both groups had comparable causes of nocturia with a baseline median voiding frequency of 2.3 (1.3, 6.3) and 2.3 (1.7, 5.3) episodes/night, respectively. The treatment group had significantly better outcomes than the placebo group in terms of median reduction in nocturia [-1.0 (-3.0, 0.0) vs. 0.0 (-2.3, 1.3) episodes/night; p < 0.001], increased median duration of the first uninterrupted sleep [1.0 (-0.3, 4.5) vs. 0.0 (-3.0, 2.3) h; p < 0.001], and improvement in N-QoL scoring, especially in the sleep/energy subscale (p = 0.019) and the total score (p = 0.016). Adverse events were comparable between groups.

CONCLUSIONS

Melatonin can be considered a safe and effective treatment for nocturia in elderly women.

Glucocorticoids coordinate the bladder peripheral clock and diurnal micturition pattern in mice

Peripheral clocks function to regulate each organ and are synchronized though various molecular and behavioral signals. However, signals that entrain the bladder clock remain elusive. Here, we show that glucocorticoids are a key cue for the bladder clock in vitro and in vivo. A pBmal1-dLuc human urothelial cell-line showed significant shifts in gene expression after cortisol treatment. In vivo, rhythmic bladder clock gene expression was unchanged by bilateral adrenalectomy but shifted 4 h forward by corticosterone administration at the inactive phase. Moreover, the bladder clock shifted 8-12 h in mice that underwent both bilateral adrenalectomy and corticosterone administration at the inactive phase. These mice showed decreases in the diurnal rhythm of volume voided per micturition, while maintaining diurnal activity rhythms. These results indicate that the diurnal rhythm of glucocorticoid signaling is a zeitgeber that overcomes other bladder clock entrainment factors and coordinates the diurnal rhythm of volume voided per micturition.

Relationship between nocturnal enuresis and sleep in children and adolescents

BACKGROUND

Nocturnal enuresis (NE) is a multifactorial and complex condition. One less understood factor in its pathophysiology is the enuretic inability to wake up when the bladder is full (impaired arousal).

OBJECTIVE

We aimed to investigate the relationship between sleep and NE in children and adolescents.

METHODS

A systematic review was performed following the PRISMA guidelines, and the electronic databases MEDLINE (via PubMed) and SCOPUS were searched until March 2022. Eligibility criteria were studies that recruited patients aged five-17 years with a diagnosis of NE according to the International Child Continence Society (ICCS), Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (DSM-5), or International Classification Criteria of Sleep Disorders-Third edition (ICSD-3) who had their sleep assessed using validated questionnaires and/or polysomnography. The tool used to analyze the risk of bias in the included studies was the risk of bias in non-randomized studies of exposure.

RESULTS

Of 1582 citations screened, nine were included, giving 1685 participants, 581 with NE. All studies were observational and half had a low risk of bias. Four studies evaluated sleep by questionnaires only; two used questionnaires and polysomnography; two used only polysomnography, and one used sleep logs and actigraphy. Sleep questionnaires showed that children with enuresis had more sleep problems than controls, especially parasomnias, breathing disorders, and daytime sleepiness. Among the polysomnography parameters, the sleep stage architecture and periodic limb movements during sleep had conflicting data between the two studies.

LIMITATIONS

The studies evaluated sleep through heterogeneous tools. They used different questionnaires; even those considered by polysomnography did not record the same channels.

CONCLUSION

It seems that enuretic children and adolescents sleep differently from those who are non-enuretic. More studies are needed to clarify the best way to assess sleep and better understand this relationship. The review protocol was registered with PROSPERO, CRD42021266338. There was no funding.

The Japan Frailty Scale is a promising screening test for frailty and pre-frailty in Japanese elderly people

Frailty is one of the most important problems in a super-aged society. It is necessary to identify frailty quickly and easily at the bedside. We developed a simple patient-reported frailty screening scale, the Japan Frailty Scale (JFS), based on the aging concept of Kampo medicine. Eight candidate questions were prepared by Kampo medicine experts, and a simple prediction model was created in the development cohort (n=434) and externally validated in an independent validation cohort (n=276). The physical indicators and questionnaires associated with frailty were also comprehensively evaluated. The reference standard for frailty or pre-frailty was determined based on the Kihon checklist. In the development cohort, four questions, nocturia (0-2), lumbago (0-2), cold sensitivity (0-2), exhaustion (0-4), and age (0-1) were selected by multivariable logistic regression analysis. The total JFS score is 0-11. Receiver-operating characteristic curve analysis of the JFS for identifying frailty status showed moderately good discrimination (area under the curve (AUC) =0.78, 95% confidence interval (CI): 0.73-0.82). At the JFS cutoff value of 3/4 for frailty or pre-frailty, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 86.9%, 53.3%, 62.8%, and 81.7%, respectively. External validation of the JFS showed moderately good discrimination (AUC=0.76, 95% CI: 0.70-0.81). The sensitivity, specificity, PPV, and NPV were 79.9%, 61.4%, 69.3%, and 73.7%, respectively. These results indicate that the JFS is a promising patient-reported clinical scale for early identification of pre-frail/frail patients at the bedside in primary care.

Does hormonal therapy affect the bladder or the kidney in postmenopausal women with and without nocturnal polyuria: Results of a pilot trial?

AIM

To observe the impact of hormonal treatment (HT) on voiding patterns and renal circadian rhythms in postmenopausal women with and without nocturnal polyuria (NP).

MATERIAL AND METHODS

A prospective, observational study was executed at the menopause clinic of a tertiary hospital. HT was based on patients' choice and was in the form of either oral and transdermal oestrogen. Participants completed a 72-hour bladder diary, completed the ICIQ-FLUTS questionnaire, recorded a renal function profile and gave a blood sample. This set of tests was done before and after 3 months of HT.

RESULTS

32 postmenopausal women with a median age of 52.5 (49.3-56.0) years were enroled in this study. Three months of HT resulted in a significant decrease in fluid intake (p < 0.001) and daytime voiding frequency (p = 0.019). No impact on nocturnal parameters was observed. Observations drawn from the questionnaires did not differ between the baseline and three-month assessments. HT led to a disappearance of the circadian rhythm of the diuresis rate and sodium clearance in patients without NP, as no significant difference between daytime and night-time values was observed (diuresis rate p = 0.3; sodium clearance p = 0.08). In patients with NP at baseline, HT did not induce a circadian rhythm of the diuresis rate and sodium clearance (p = 0.2; p = 0.7). In contrast, free water clearance did change to a clear circadian rhythm (p = 0.02).

CONCLUSION

HT led to a significant reduction in both fluid intake and daytime frequency. In women without NP, HT led to a disruption of the circadian rhythms of water and salt diuresis. In patients with NP, a limited normalisation of the circadian rhythm of free water clearance was observed after three months of HT. CLINICAL TRIAL REGISTRATION NUMBER FROM CLINICALTRIALS.GOV: NCT04891926.

Association between before-bedtime passive body heating and nocturia during the cold season among older adults

Background Cold exposure induces lower urinary tract symptoms including nocturia. Cold-induced detrusor overactivity can be alleviated by increasing skin temperature in rats. However, no study has shown an association between passive heating with hot-water bathing and nocturia among humans.Methods We included 1,051 Japanese community-dwelling older adults (mean age 71.7 years) in this cross-sectional study from 2010 to 2014. The number of nocturnal voids was recorded in a self-administered urination diary. Nocturia was defined as ≥2 nocturnal voids. We evaluated bathing conditions in the participants' houses.Results Hot-water bathing (n = 888) was associated with a lower prevalence of nocturia than no bathing (n = 163), independent of potential confounders including age, sex, obesity, income, physical activity, diabetes, medication (diuretics, nondiuretic antihypertensives, and hypnotics), depressive symptoms, indoor/outdoor temperature, and day length (odds ratio [OR]: 0.68, 95% confidence interval [CI]: 0.48-0.97; p = 0.035). Compared with the quartile group with the longest bath-to-bed interval (range: 161-576 min), the second and third quartile groups (range: 61-100 and 101-160 min, respectively) were associated with a lower prevalence of nocturia, after adjusting for water temperature and bathing duration besides the same covariates (OR: 0.60, 95% CI: 0.38-0.96; p = 0.031 and OR: 0.59, 95% CI: 0.37-0.94; p = 0.025, respectively).Conclusion Hot-water bathing, particularly with a bath-to-bed interval of 61-160 min, was significantly associated with a lower prevalence of nocturia among older adults.

Evaluation of the influence of a history of childhood nocturnal enuresis on nighttime urinary frequency and the causes of nocturia in adults

OBJECTIVES

To examine whether a history of nocturnal enuresis affects nighttime urinary frequency and to evaluate nocturia etiologies in adults.

METHODS

A total of 143 participants with at least one episode of nocturia per night were included in this study. The self-reported questionnaire collected data on demographic characteristics, medical history, history of nocturnal enuresis in elementary school, lower urinary tract symptoms, and frequency-volume charts.

RESULTS

A history of nocturnal enuresis was observed in 52.4% of participants. However, night-time urinary frequency was significantly lower in participants with a history of nocturnal enuresis in elementary school than in those without such history. On multivariate analysis, a history of nocturnal enuresis was also negatively associated with nighttime urinary frequency (p<0.01). There was a collinearity effect between age and nighttime urinary frequency. A history of nocturnal enuresis did not affect the presence of nocturnal polyuria or overactive bladder in participants. However, sleep disturbances were fewer in participants with a history of nocturnal enuresis (odds ratio 0.404).

CONCLUSIONS

A history of nocturnal enuresis might be negatively associated with nighttime urinary frequency due to fewer sleep disturbances. Further, progression of nocturia may depend on conditions, such as age and acquired diseases.

The Influence of Salt Sensitivity Phenotype on Sodium Excretion and Diuresis: A Chrononutrition Pilot Study

BACKGROUND

Chrononutrition studies on interaction of diet/nutrients on endogenous circadian clocks and meal timing on metabolic homeostasis may be of importance in the management of nocturnal polyuria (NP), owing to loss of circadian rhythm in nighttime urination. Dietary salt restriction is an increasingly popular lifestyle recommendation for NP patients.

AIM

This study aims to evaluate the effect of an acute salt load on diuresis and to study the phenomenon of salt sensitivity. Methodology. Young, healthy men (n = 21, fasted and sober) ingested 500 ml of water on the control day and 8 g and 12 g of salt with water (500 ml) on two other days. Blood and urine samples were collected at 0 hrs, 2 hrs, and 4 hrs and voided volumes were recorded. Diuresis, serum and urine osmolality, sodium, potassium, urea, and creatinine were measured. Salt sensitivity was determined based on the rate of sodium excretion.

RESULTS

Compared to 8 g, ingestion of 12 g of salt significantly increased diuresis after 4 hrs. Pure water load induced fast diuresis, whereas salt and water load initially reduced diuresis and promoted late increase in diuresis. The total voided volume was significantly lower in the salt sensitive individuals.

CONCLUSION

Taken together, salt sensitivity profile and type and time of fluid intake are important considerations to build effective personalized lifestyle recommendations for NP patients, which needs further investigation.

Time-of-day dependent changes in guinea pig bladder afferent mechano-sensitivity

The voiding of urine has a clear circadian rhythm with increased voiding during active phases and decreased voiding during inactive phases. Bladder spinal afferents play a key role in the regulation of bladder storage and voiding, but it is unknown whether they exhibit themselves a potential circadian rhythm. Therefore, this study aimed to determine the mechano- and chemo- sensitivity of three major bladder afferent classes at two opposite day-night time points. Adult female guinea pigs underwent conscious voiding monitoring and bladder ex vivo single unit extracellular afferent recordings at 0300 h and 1500 h to determine day-night modulation of bladder afferent activity. All guinea pigs voided a higher amount of urine at 1500 h compared to 0300 h. This was due to an increased number of voids at 1500 h. The mechano-sensitivity of low- and high-threshold stretch-sensitive muscular-mucosal bladder afferents to mucosal stroking and stretch was significantly higher at 1500 h compared to 0300 h. Low-threshold stretch-insensitive mucosal afferent sensitivity to stroking was significantly higher at 1500 h compared to 0300 h. Further, the chemosensitivity of mucosal afferents to N-Oleoyl Dopamine (endogenous TRPV1 agonist) was also significantly increased at 1500 h compared to 0300 h. This data indicates that bladder afferents exhibit a significant time-of-day dependent variation in mechano-sensitivity which may influence urine voiding patterns. Further studies across a 24 h period are warranted to reveal potential circadian rhythm modulation of bladder afferent activity.

Diurnal rhythms of urine volume and electrolyte excretion in healthy young men under differing intensities of daytime light exposure

In humans, most renal functions, including urine volume and electrolyte excretions, have a circadian rhythm. Light is a strong circadian entrainment factor and daytime-light exposure is known to affect the circadian rhythm of rectal temperature (RT). The effects of daytime-light exposure on the diurnal rhythm of urinary excretion have yet to be clarified. The aim of this study was to clarify whether and how daytime exposure to bright-light affects urinary excretions. Twenty-one healthy men (21–27 years old) participated in a 4-day study involving daytime (08:00–18:00 h) exposure to two light conditions, Dim (< 50 lx) and Bright (~ 2500 lx), in a random order. During the experiment, RT was measured continuously. Urine samples were collected every 3 ~ 4 h. Compared to the Dim condition, under the Bright condition, the RT nadir time was 45 min earlier (p = 0.017) and sodium (Na), chloride (Cl), and uric acid (UA) excretion and urine volumes were greater (all p < 0.001), from 11:00 h to 13:00 h without a difference in total daily urine volume. The present results suggest that daytime bright light exposure can induce a phase shift advance in urine volume and urinary Na, Cl, and UA excretion rhythms.

Association of nocturia and cardiovascular disease: Data from the National Health and Nutrition Examination Survey

AIMS

To investigate the association of nocturia with the prevalence of cardiovascular disease (CVD) using the National Health and Nutrition Examination Survey (NHANES) data.

METHODS

Among the 40 790 individuals who participated in NHANES from 2005 to 2012, 14 114 adults were analyzed in this study. A participant was considered to have nocturia if they have two or more voiding episodes nightly. In addition, participants with nocturia more than four times in a day were considered to have severe nocturia. A multivariate logistic regression analysis with adjustment for confounding variables, including age, sex, race, body mass index (BMI), smoking status, alcohol consumption, sleeping time, dyslipidemia, hypertension, and diabetes mellitus was performed with 1:1 propensity score matching (PSM).

RESULTS

Nocturia occurred in 4610 individuals (32.7%). The prevalence of CVD was significantly higher in men, older individuals, those with higher BMI, smokers, and those with diabetes, hypertension, and hyperlipidemia. There was also a significantly higher prevalence of nocturia in the participants with CVD. Multivariate analysis showed that odds ratios (ORs) of mild and severe nocturia for CVD were 1.23 (95% confidence interval [CI]: 1.08-1.39) and 1.74 (95% CI: 1.39-2.17), respectively. After 1:1 PSM, the ORs of mild and severe nocturia were 1.27 (95% CI: 1.10-1.48) and 1.73 (95% CI: 1.33-2.26), respectively, showing statistical significance.

CONCLUSION

Data from the NHANES indicate that CVD was significantly associated with the prevalence of nocturia, after taking major confounding factors into account. Furthermore, the risk for CVD increases with increasing nocturia severity.

Urothelium-Specific Deletion of Connexin43 in the Mouse Urinary Bladder Alters Distension-Induced ATP Release and Voiding Behavior

Connexin43 (Cx43), the main gap junction and hemichannel forming protein in the urinary bladder, participates in the regulation of bladder motor and sensory functions and has been reported as an important modulator of day-night variations in functional bladder capacity. However, because Cx43 is expressed throughout the bladder, the actual role played by the detrusor and the urothelial Cx43 is still unknown. For this purpose, we generated urothelium-specific Cx43 knockout (uCx43KO) mice using Cre-LoxP system. We evaluated the day-night micturition pattern and the urothelial Cx43 hemichannel function of the uCx43KO mice by measuring luminal ATP release after bladder distention. In wild-type (WT) mice, distention-induced ATP release was elevated, and functional bladder capacity was decreased in the animals' active phase (nighttime) when Cx43 expression was also high compared to levels measured in the sleep phase (daytime). These day-night differences in urothelial ATP release and functional bladder capacity were attenuated in uCx43KO mice that, in the active phase, displayed lower ATP release and higher functional bladder capacity than WT mice. These findings indicate that urothelial Cx43 mediated ATP signaling and coordination of urothelial activity are essential for proper perception and regulation of responses to bladder distension in the animals' awake, active phase.

Medical history of nocturnal enuresis during school age is an independent risk factor for nocturia in adults: The Nagahama study

AIM

To evaluate the relationship between nocturia and medical history of nocturnal enuresis: two conditions where diurnal urination rhythm is disturbed.

METHODS

The Nagahama study is a longitudinal population-based health survey involving people aged 30-75 years in Nagahama city, Japan. Our analysis included 5,402 participants who completed enuresis and International Prostate Symptom Score questionnaires. Associations between nocturnal enuresis and nocturia were evaluated cross-sectionally and longitudinally with three models: (1) univariate analysis; (2) adjusted for basic characteristics (e.g., age, sex, body mass index, activity, alcohol, and smoking); and (3) adjusted for basic and clinical variables (e.g., hyperglycemia, hyperlipidemia, hypertension, renal insufficiency, insomnia, obstructive sleep apnea, and mental health).

RESULTS

In total, 1,613 participants (29.9%) had a medical history of enuresis. The mean night-time frequency was 0.73 at baseline and 0.85 at the 5-year follow-up. The cross-sectional analysis showed participants with a medical history of enuresis had night-time frequency more often than those without this history (0.84 vs. 0.68, p < .0001). Significant differences were observed in Models 2 (p < .0001) and 3 (p < .0001). The longitudinal analysis showed nocturia progression was significantly related to a history of enuresis, with odds ratios of 1.32 (p < .0001) in Model 1, 1.21 (p < .01) in Model 2, and 1.22 (p < .01) in Model 3.

CONCLUSIONS

Medical history of enuresis during school age was significantly related to nocturia in adulthood in the cross-sectional analysis, and to progression to nocturia in the longitudinal analysis. These two conditions may possess a common causative association.

The Urothelium: Life in a Liquid Environment

The urothelium, which lines the renal pelvis, ureters, urinary bladder, and proximal urethra, forms a high-resistance but adaptable barrier that surveils its mechanochemical environment and communicates changes to underlying tissues including afferent nerve fibers and the smooth muscle. The goal of this review is to summarize new insights into urothelial biology and function that have occurred in the past decade. After familiarizing the reader with key aspects of urothelial histology, we describe new insights into urothelial development and regeneration. This is followed by an extended discussion of urothelial barrier function, including information about the roles of the glycocalyx, ion and water transport, tight junctions, and the cellular and tissue shape changes and other adaptations that accompany expansion and contraction of the lower urinary tract. We also explore evidence that the urothelium can alter the water and solute composition of urine during normal physiology and in response to overdistension. We complete the review by providing an overview of our current knowledge about the urothelial environment, discussing the sensor and transducer functions of the urothelium, exploring the role of circadian rhythms in urothelial gene expression, and describing novel research tools that are likely to further advance our understanding of urothelial biology.

Long-term administration of alpha-1 blocker can reverse the micturition pattern in a bladder outlet obstruction murine model

OBJECTIVE

To investigate the effect of chronic administration of an alpha-1 blocker on micturition patterns in long-term partial bladder outlet obstruction.

METHODS

Mice were divided into three groups: a normal group, in which animals were fed a standard diet; a partial bladder outlet obstruction group, in which the proximal urethra was tied and animals were fed a standard diet; and a partial bladder outlet obstruction + naftopidil group, in which the proximal urethra was tied and animals were fed a standard diet containing naftopidil. Micturition behavior was evaluated in all groups for 6 months after partial bladder outlet obstruction surgery. The parameters evaluated included voided volume, time per void, urination frequency and total urine volume. Quantitative assessment of gene expression was also carried out.

RESULTS

Total urine volume, as well as total and average voided volume during night, was significantly decreased in partial bladder outlet obstruction + naftopidil mice compared with partial bladder outlet obstruction animals. The levels of transcripts encoding 5-hydroxytryptamine 2A and tissue inhibitor of metalloproteinase 2 were significantly decreased in the partial bladder outlet obstruction + naftopidil group compared with the partial bladder outlet obstruction group.

CONCLUSIONS

Long-term administration of an alpha-1 blocker seems to reverse the disturbance of the micturition pattern caused by partial bladder outlet obstruction. Mechanistically, this effect might be mediated by changes in the expression of a serotonin receptor and/or in the activity of the fibrogenesis pathway.

Evaluation of sleep hygiene and prevalence of sleep disorders in patients with monosymptomatic enuresis. Usefulness of the BEARS sleep screening tool

OBJECTIVES

To analyze if there is a higher prevalence of sleep disturbances and hygiene disorders in patients with monosymptomatic enuresis (MEN) with respect to general population and to patients with corrected MEN. Assess the usefulness of the BEARS sleep disorder screening tool for children with MEN.

MATERIAL AND METHODS

Transverse observational study (n=341) classified as: MEN (n=122), corrected MEN (≥ 1 one year without recurrence) (ANTENUR) (n=47) and controls (n=172). The BEARS childhood sleep disorder screening questionnaire was used. Clinical variables were collected, as well as variables related to sleep hygiene.

STATISTICS

Chi-square, Student's t, ANOVA, Mann-Whitney U and Kruskal-Wallis. Significance p<.05.

RESULTS

Mean age 9.7±3.0 years. There were no statistically significant differences in terms of age, sex, BMI, history of tonsillectomy, asthma and sleep time hours. With respect to sleep hygiene, patients with MEN presented a higher percentage of alterations than controls. As for the BEARS questionnaire, it showed a higher prevalence of sleep disorders in the group of patients with MEN, with respect to the other two groups: 60.7% (n=74) versus 18.6% (n=32) and 38.3% (n=18) of controls and ANTENUR, respectively (p<.05).

CONCLUSIONS

Children with MEN had a higher prevalence of sleep disturbances and sleep disorders than controls. The BEARS questionnaire is a useful clinical tool in the detection of sleep disorders in children.

Chronoradiation Therapy for Prostate Cancer: Morning Proton Beam Therapy Ameliorates Worsening Lower Urinary Tract Symptoms

Background and Purpose: Worsening lower urinary tract symptoms (LUTS) are a frequent adverse event following proton beam therapy (PBT) for localized prostate cancer. We investigated the differences in worsening LUTS among patients who received PBT at different times of day. Participants and Methods: Among 173 patients who underwent PBT for prostate cancer, 168 patients (median age 68.5 years) completed international prostate symptom score (IPSS) questionnaires and were included. Changes in the IPSS from baseline to the end of PBT were assessed by multiple linear regression analysis for age, National Comprehensive Cancer Network risk classification, androgen deprivation therapy, fractional PBT dose, clinical target volume, severity of IPSS, diabetes, LUTS medication use before PBT, anti-coagulant therapy and radiation time of day (morning (08:30–10:30), around noon (10:31–14:30), and late afternoon (14:31–16:30)). Results: IPSS total score and IPSS-Quality of Life (QoL) score (12 patients were excluded due to missing IPSS-QoL score) increased from eight to 14.9 (p < 0.0001) and from two to four (p < 0.0001), respectively. Time of day (morning) was the only determinant for worsening LUTS (β = −0.24, p < 0.01), voiding subscore (β = −0.22, p < 0.05) and IPSS-QoL (β = −0.27, p < 0.005), and was a determinant in item four (urgency) (β = −0.28, p < 0.005) with age (β = 0.19, p < 0.05). Conclusions: Morning PBT for localized prostate cancer significantly ameliorated worsening LUTS and improved QoL compared with treatment around noon or late afternoon. Chronoradiation therapy for localized prostate cancer may be effective and further research to elucidate the underlying mechanism is warranted.

Circadian clock and cancer: From a viewpoint of cellular differentiation

The circadian clock controls and adapts diverse physiological and behavioral processes according to Earth's 24-h cycle of environmental changes. The master pacemaker of the mammalian circadian clock resides in the hypothalamic suprachiasmatic nucleus, but almost all cells throughout the body show circadian oscillations in gene expression patterns and associated functions. Recent studies have shown that the circadian clock gradually develops during embryogenesis. Embryonic stem cells and induced pluripotent stem cells do not show circadian oscillations of gene expression, but gradually develop circadian clock oscillation during differentiation; thus, the developmental program of circadian clock emergence appears closely associated with cellular differentiation. Like embryonic stem cells, certain cancer cell types also lack the circadian clock. Given this similarity between embryonic stem cells and cancer cells, interest is growing in the contributions of circadian clock dysfunction to dedifferentiation and cancer development. In this review, we summarize recent advances in our understanding of circadian clock emergence during ontogenesis, and discuss possible associations with cellular differentiation and carcinogenesis. Considering the multiple physiological functions of circadian rhythms, circadian abnormalities might contribute to a host of diseases, including cancer. Insights on circadian function could lead to the identification of biomarkers for cancer diagnosis and prognosis, as well as novel targets for treatment.

Persistent myopathy despite release of partial obstruction: in vivo reversal of dysfunction and transcriptional responses using rapamycin

Current and potential medical therapy for obstruction-induced myopathic bladder dysfunction (from benign prostatic hyperplasia or posterior urethral valves) focuses on symptoms. The persistent tissue pathology and dysfunction after release of obstruction is often deemed irreversible without any systematic therapeutic approaches. As rapamycin can attenuate bladder smooth muscle hypertrophy and dysfunction during the genesis of partial obstruction in vivo, we tested whether rapamycin could improve persistent function after release of obstruction (de-obstruction or REL). Female Sprague-Dawley rat bladders were partially obstructed (PBO) by suturing around both the urethra and a para-urethral steel rod, then removing the rod. One day prior to release of obstruction (preREL), voiding parameters and residual urine volume of preREL+future rapa, preREL+future veh groups were recorded. Release of obstruction (REL) was performed by suture removal following 6 weeks of PBO. For 4 more weeks after the de-obstruction, REL animals were randomized to rapamycin (REL+rapa) or vehicle (REL+veh). PBO for 6 weeks were used as positive controls. In shams, the urethra was exposed, but no suture tied. Voiding parameters and residual urine volume were measured prior to sacrifice of sham and REL+veh or REL+rapa, and PBO. Rapamycin efficacy was tested by pair-wise comparison of changes in individual voiding data from preREL+future veh or preREL+future rapa versus REL+veh or REL+rapa, respectively, as well as by comparisons of REL+veh to REL+rapa groups. Bladders were weighed and processed for a high-throughput QPCR array, and histopathology. Bladder/body mass ratios with PBO increased significantly and remained higher in the release phase in REL+veh animals. REL+rapa versus REL+veh improved residual volumes and micturition fractions toward sham levels. Three genes encoding extracellular proteins, BMP2, SOD3, and IGFBP7, correlated with functional improvement by Pearson's correlations. The promoters of these genes showed enrichment for several motifs including circadian E-boxes. While obstruction and REL augmented CLOCK and NPAS2 expression above sham levels, rapamycin treatment during release significantly blocked their expression. This experimental design of pharmaco-intervention during the de-obstruction phase revealed a novel pathway dysregulated during the clinically relevant treatment phase of obstructive bladder myopathy.

Can we predict the success of prostatic surgery for male lower urinary tract symptoms: ICI-RS 2018?

AIMS

Male lower urinary tract symptoms (LUTS) are common and bothersome symptoms in the aging population, of which the etiology is multifactorial. Prostatic surgery may be considered to alleviate some of these LUTS, especially in patients in which benign prostatic obstruction is believed to be the underlying cause. The aim of this paper is to discuss underlying pathophysiology, signs, and conditions that may lead to success or failure after prostatic surgery in male patients with LUTS.

METHODS

The paper is a report of presentations and subsequent discussions at the annual International Consultation on Incontinence Research Society, in June 2018 in Bristol.

RESULTS AND CONCLUSIONS

Unfavorable outcomes after prostatic surgery are reported in 25% to 30% of the patients. This may be due to persistent or de novo symptoms, related to the multifactorial origin of symptoms. Specific underlying conditions such as with detrusor overactivity, detrusor underactivity, and nocturnal polyuria are discussed in their relationship with prostatic surgery. Knowledge gaps are addressed and specific research questions proposed.

Practical recommendations of the EAU-ESPU guidelines committee for monosymptomatic enuresis-Bedwetting

BACKGROUND AND AIMS

The objective of this update of the EAU-ESPU guidelines recommendations for nocturnal enuresis was to review the recent published literature of studies, reviews, guidelines regarding the etiology, diagnosis and treatment options of nocturnal enuresis and transform the information into a practical recommendation strategy for the general practitioner, pediatrician, pediatric urologist and urologist.

MATERIAL AND METHODS

Since 2012 a monthly literature search using Scopus® was performed and the relevant literature was reviewed and prospectively registered on the European Urology bedwetting enuresis resource center (http://bedwetting.europeanurology.com/). In addition, guideline papers and statements of the European Society for Paediatric Urology (ESPU), the European Association of Urology (EAU), the National Institute for Health and Care Excellence (NICE) and the International Children Continence Society (ICCS) were used to update the knowledge and evidence resulting in this practical recommendation strategy. Recommendations have been discussed and agreed within the working group of the EAU-ESPU guidelines committee members.

RESULTS

The recommendations focus to place the child and his family in a control position. Pragmatic analysis is made of the bedwetting problem by collecting voiding and drinking habits during the day, measuring nighttime urine production and identification of possible risk factors such as high-volume evening drinking, nighttime overactive bladder, behavioral or psychological problems or sleep disordered breathing. A questionnaire will help to identify those risk factors.

CONCLUSION

Motivation of the child is important for success. Continuous involvement of the child and the family in the treatment will improve treatment compliance, success and patient satisfaction.

Pathophysiological Mechanisms of Nocturia and Nocturnal Polyuria: The Contribution of Cellular Function, the Urinary Bladder Urothelium, and Circadian Rhythm

Alterations to arginine vasopressin (AVP) secretion, the urinary bladder urothelium (UT) and other components of the bladder, and the water homeostasis biosystem may be relevant to the pathophysiology of nocturia and nocturnal polyuria (NP). AVP is the primary hormone involved in water homeostasis. Disruption to the physiological release of AVP or its target effects may relate to several urinary disturbances. Circadian dysregulation and the effects of aging, for example, the development of oxidative stress and mitochondrial dysfunction, may play a role in nocturia voiding symptoms. The urinary bladder UT not only acts as a highly efficient barrier that is maintained during the filling and voiding of the urinary bladder, but is also capable of sensory and transducer function through a network of functional receptors and ion channels that enable reciprocal communication between UT cells and neighboring elements of the bladder mucosa and wall. Functional components of the UT (eg, claudins and receptors or ion channels) play important roles in AVP-mediated water homeostasis. These components and functions involved in water homeostasis, as well as kidney function, may be affected by the aging process, including age-related mitochondrial dysfunction. The characteristics of NP are discussed and the association between NP and circadian rhythm is examined in light of reports that suggest that nocturia should be considered as a type of circadian dysfunction. Many possible pathologic mechanisms that underlie nocturia and NP have been identified. Future studies may provide further insight into pathophysiology with the hope of identifying new treatment modalities.

Efficacy of novel β3 -adrenoreceptor agonist vibegron on nocturia in patients with overactive bladder: A post-hoc analysis of a randomized, double-blind, placebo-controlled phase 3 study

Objectives

To investigate the efficacy of vibegron on nocturia in patients with overactive bladder.

Methods

Among the Japanese overactive bladder patients enrolled in the placebo‐controlled, multicenter, randomized, double‐blind phase 3 study of vibegron, a total of 669 patients with nocturia (≥1 nocturnal void) were included. Changes from baseline in micturition parameters were compared for vibegron treatment (50 and 100 mg/day) versus placebo. Correlations of hours of undisturbed sleep with the frequency of nocturnal voiding and the volume of the first nocturnal voiding were examined. Demographics and baseline characteristics contributing to reduction in the frequency of nocturnal voiding were also analyzed.

Results

At week 12, the frequency of nocturnal voiding was reduced from baseline by 0.74 and 0.78, respectively, for the vibegron 50 and 100 mg groups; the reductions were significant when compared with the placebo group (P < 0.05 and P < 0.001, respectively). The mean volume of nocturnal voids and the volume of the first nocturnal voiding were significantly greater in the vibegron groups than in the placebo group. The vibegron groups showed significant correlations of hours of undisturbed sleep with the changes in the frequency of nocturnal voiding and in the volume of the first nocturnal voiding. Vibegron treatment, no previous treatment with anticholinergics, ≥12 voids per day and hours of undisturbed sleep <180 min significantly contributed to a reduction in the frequency of nocturnal voiding.

Conclusions

Vibegron is a useful therapeutic option for improving nocturia in patients with overactive bladder.

Suppression of Urinary Voiding by Conditional High Frequency Stimulation of the Pelvic Nerve in Conscious Rats

Female Wistar rats were instrumented to record bladder pressure and to stimulate the left pelvic nerve. Repeated voids were induced by continuous infusion of saline into the bladder (11.2 ml/h) via a T-piece in the line to the bladder catheter. In each animal tested (n = 6) high frequency pelvic nerve stimulation (1-3 kHz, 1-2 mA sinusoidal waveform for 60 s) applied within 2 s of the onset of a sharp rise in bladder pressure signaling an imminent void was able to inhibit micturition. Voiding was modulated in three ways: (1) Suppression of voiding (four rats, n = 13 trials). No fluid output or a very small volume of fluid expelled (<15% of the volume expected based on the mean of the previous 2 or 3 voids). Voiding suppressed for the entirety of the stimulation period (60 s) and resumed within 37 s of stopping stimulation. (2) Void deferred (four rats, n = 6 trials). The imminent void was suppressed (no fluid expelled) but a void occurred later in the stimulation period (12-44 s, mean 24.5 ± 5.2 s after the onset of the stimulation). (3) Reduction in voided volume (five rats, n = 20 trials). Voiding took place but the volume of fluid voided was 15-80% (range 21.8-77.8%, mean 45.3 ± 3.6%) of the volume expected from the mean of the preceding two or three voids. Spontaneous voiding resumed within 5 min of stopping stimulation. Stimulation during the filling phase in between voids had no effect. The experiments demonstrate that conditional high frequency stimulation of the pelvic nerve started at the onset of an imminent void can inhibit voiding. The effect was rapidly reversible and was not accompanied by any adverse behavioral side effects.

Circadian regulation of renal function

The kidneys regulate many vital functions that require precise control throughout the day. These functions, such as maintaining sodium balance or regulating arterial pressure, rely on an intrinsic clock mechanism that was commonly believed to be controlled by the central nervous system. Mounting evidence in recent years has unveiled previously underappreciated depth of influence by circadian rhythms and clock genes on renal function, at the molecular and physiological level, independent of other external factors. The impact of circadian rhythms in the kidney also affects individuals from a clinical standpoint, as the loss of rhythmic activity or clock gene expression have been documented in various cardiovascular diseases. Fortunately, the prognostic value of examining circadian rhythms may prove useful in determining the progression of a kidney-related disease, and chronotherapy is a clinical intervention that requires consideration of circadian and diurnal rhythms in the kidney. In this review, we discuss evidence of circadian regulation in the kidney from basic and clinical research in order to provide a foundation on which a great deal of future research is needed to expand our understanding of circadian relevant biology.

Chronic implantation of cuff electrodes on the pelvic nerve in rats is well tolerated and does not compromise afferent or efferent fibre functionality

OBJECTIVE

Neuromodulation of autonomic nerve activity to regulate physiological processes is an emerging field. Vagal stimulation has received most attention whereas the potential of modulate visceral function by targeting autonomic nerves within the abdominal cavity remains under-exploited. Surgery to locate intra-abdominal targets is inherently more stressful than for peripheral nerves. Electrode leads risk becoming entrapped by intestines and loss of functionality in the nerve-target organ connection could result from electrode migration or twisting. Since nociceptor afferents are intermingled with similar-sized visceral autonomic fibres, stimulation may induce pain. In anaesthetised rats high frequency stimulation of the pelvic nerve can suppress urinary voiding but it is not known how conscious animals would react to this procedure. Our objective therefore was to determine how rats tolerated chronic implantation of cuff electrodes on the pelvic nerve, whether nerve stimulation would be aversive and whether nerve-bladder functionality would be compromised.

APPROACH

We carried out a preliminary de-risking study to investigate how conscious rats tolerated chronic implantation of electrodes on the pelvic nerve, their responsiveness to intermittent high frequency stimulation and whether functionality of the nerve-bladder connection became compromised.

MAIN RESULTS

Implantation of cuff electrodes was well-tolerated. The normal diurnal pattern of urinary voiding was not disrupted. Pelvic nerve stimulation (up to 4 mA, 3 kHz) for 30 min periods evoked mild alerting at stimulus onset but no signs of pain. Stimulation evoked a modest (<0.5 °C) increase in nerve temperature but the functional integrity of the nerve-bladder connection, reflected by contraction of the detrusor muscle in response to 10 Hz nerve stimulation, was not compromised.

SIGNIFICANCE

Chronic implantation of cuff electrodes on the pelvic nerve was found to be a well-tolerated procedure in rats and high frequency stimulation did not lead to loss of nerve functionality. Pelvic nerve stimulation has development potential for normalizing voiding dysfunction in conscious rats.

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

The prevalence of lower urinary tract (LUT) symptoms increases with age but the etiology is unknown. This article aims to identify research directions that clarify the basis of this association. The initial question is whether biological age is the variable of interest or a time-dependent accumulation of factors that impact on LUT function at rates that differ between individuals. In particular, the accumulation of conditions or agents due to inflammatory states or tissue ischemia is important. Much of the above has been concerned with changes to bladder function and morphology. However, the outflow tract function is also affected, in particular changes to the function of external sphincter skeletal muscle and associated sacral motor nerve control. Nocturia is a cardinal symptom of LUT dysfunction and is more prevalent with aging. Urine production is determined by diurnal changes to the production of certain hormones as well as arterial blood pressure and such diurnal rhythms are blunted in subjects with nocturia, but the causal links remain to be elucidated. Changes to the central nervous control of LUT function with age are also increasingly recognized, whether in mid-brain/brainstem regions that directly affect LUT function or in higher centers that determine psycho-social and emotional factors impinging on the LUT. In particular, the linkage between increasing white matter hyperintensities and LUT dysfunction during aging is recognized but not understood. Overall, a more rational approach is being developed to link LUT dysfunction with factors that accumulate with age, however, the precise causal pathways remain to be characterized. Neurourol. Urodynam. 36:854-858, 2017. © 2017 Wiley Periodicals, Inc.

Nocturia increases the incidence of depressive symptoms: a longitudinal study of the HEIJO-KYO cohort

OBJECTIVES

To evaluate the association between nocturia and the incidence of depressive symptoms.

PARTICIPANTS AND METHODS

Of 1 127 participants in the HEIJO-KYO population-based cohort, 866 elderly individuals (mean age 71.5 years) without depressive symptoms at baseline were followed for a median period of 23 months. Nocturnal voiding frequency was logged using a standardized urination diary and nocturia was defined as a frequency of ≥2 voids per night. Depressive symptoms were assessed using the Geriatric Depression Scale.

RESULTS

During the follow-up period, 75 participants reported the development of depressive symptoms (score ≥6). The nocturia group (n = 239) exhibited a significantly higher hazard ratio (HR) for incident depressive symptoms than the non-nocturia group (n = 627) in the Cox proportional hazard model, which was adjusted for age, gender, alcohol consumption, day length and presence of hypertension and chronic kidney disease (HR 1.69, 95% confidence interval [CI] 1.05-2.72; P = 0.032]. The significance remained after adjustment for sleep disturbances (HR 1.68, 95% CI 1.02-2.75; P = 0.040). Analysis stratified by gender showed that the association between nocturia and the incidence of depressive symptoms was significant in men (HR 2.51, 95% CI 1.27-4.97; P = 0.008) but not in women (HR 1.12, 95% CI 0.53-2.44; P = 0.74).

CONCLUSIONS

Nocturia is significantly associated with a higher incidence of depressive symptoms in the general elderly population, and gender differences may underlie this association.

Lower urinary tract symptoms and metabolic disorders: ICI-RS 2014

AIMS

To investigate the link between lower urinary tract symptoms (LUTS) and metabolic disorders.

MATERIALS AND METHODS

This report results from presentations and subsequent discussions about LUTS and metabolic disorders at the International Consultation on Incontinence Research Society (ICI-RS) in Bristol, 2014.

RESULTS

There are common pathophysiological determinants for the onset of LUTS and the metabolic syndrome (MetS). Both conditions are multifactorial, related to disorders in circadian rhythms and share common risk factors. As in men with erectile dysfunction, these potentially modifiable lifestyle factors may be novel targets to prevent and treat LUTS. The link between LUTS and metabolic disorders is discussed by using sleep, urine production and bladder function as underlying mechanisms that need to be further explored during future research.

CONCLUSION

Recent findings indicate a bidirectional relationship between LUTS and the MetS. Future research has to explore underlying mechanisms to explain this relationship, in order to develop new preventive and therapeutic recommendations, such as weight loss and increasing physical activity. The second stage is to determine the effect of these new treatment approaches on the severity of LUTS and each of the components of the MetS.

Translational Research for Pediatric Lower Urinary Tract Dysfunction

This review provides a comprehensive view of translational research aimed at elucidating the pathophysiology of pediatric lower urinary tract dysfunction (LUTD). A web search was conducted according to combinations of keywords, and the significance of each article was defined by the author. The dramatic evolution of the mass analysis method of genomes, transcripts, and proteins has enabled a comprehensive analysis of molecular events underlying diseases, and these methodologies have also been applied to pediatric LUTD. In genetic analyses of syndromes underlying daytime incontinence, urofacial (Ochoa) syndrome may be creating a prototype of a new research approach. Nocturnal enuresis has long been studied genetically, and several candidate loci have been reported. However, the pursuit for enuresis genes has been abandoned partly because genetic association and enuresis phenotype (bladder or renal type) could not be linked. Enuresis associated with diabetes insipidus has provided new insights into the etiology of the diseases. A chronobiological approach may shed new light on this area. Posterior urethral valves and neurogenic bladders have attracted the interest of pediatric urologists to the smooth muscle biology of the bladder. Bladder exstrophy and cloacal anomalies are rare but major anomalies caused by defective urorectal development and have recently been studied from a genetic standpoint. Translational studies for pediatric LUTD may be extended to adult bladder disease, or to application of precision medicine for diseased children.

Octodon degus, a new model to study the agonist and plexus-induced response in the urinary bladder

Urinary bladder function consists in the storage and controlled voiding of urine. Translational studies require animal models that match human characteristics, such as Octodon degus, a diurnal rodent. This study aims to characterize the contractility of the detrusor muscle and the morphology and code of the vesical plexus from O. degus. Body temperature was measured by an intra-abdominal sensor, the contractility of detrusor strips was evaluated by isometric tension recording, and the vesical plexus was studied by electrical field stimulation (EFS) and immunofluorescence. The animals showed a diurnal chronotype as judged from core temperature. The myogenic contractile response of the detrusor muscle to increasing doses of KCl reached its maximum (31.04 mN/mm²) at 60 mM. In the case of cumulative dose-response of bethanecol, the maximum response (37.42 mN/mm²) was reached at 3.2 × 10^-4 M. The response to ATP was clearly smaller (3.8 mN/mm²). The pharmacological dissection of the EFS-induced contraction identified ACh and sensory fibers as the main contributors to this response. The neurons of the vesical plexus were located mainly in the trigone area, grouped in big and small ganglia. Out of them, 48.1 % of the neurons were nitrergic and 62.7 % cholinergic. Our results show functional and morphological similarities between the urinary bladder of O. degus and that of humans.

Impact of Living at the Japanese Antarctic Research Expedition Base on Urinary Status

OBJECTIVES

Urinary disorders are generally well understood, but there are few reports on the urinary status of people living in unusual climates such as the polar regions. We studied the impact of living conditions on the urinary status of members of the Japanese Antarctic Research Expedition.

METHODS

This prospective study enrolled 12 consenting members of the wintering party stationed at the Syowa Station in Antarctica between November 2012 and March 2014. The subjects completed questionnaires (the International Prostate Symptom Score [IPSS], Overactive Bladder Syndrome Score [OABSS] and Pittsburgh Sleep Quality Index [PSQI]) and kept daily voiding dairies for 3 days consecutively every 2 months.

RESULTS

Compared with baseline values, the mean scores on all the questionnaires decreased during the stay in Antarctica, from 3.42 to 2.31 for the IPSS, 1.25 to 0.986 for the OABSS, and 4.58 to 3.78 on the PSQI. A significant difference was noted in the scores of seven subjects with a 3 point or more decrease in IPSS score and five members with a decrease less than 3 points (-2.22 vs 0.448, P = 0.0416).

CONCLUSION

This is the first survey of the urinary status of people living in a polar environment. The findings obtained by questionnaires and voiding dairies indicated that urination and sleep status did not worsen during the stay in Antarctica.

Nocturia: The circadian voiding disorder

Nocturia is a prevalent condition of waking to void during the night. The concept of nocturia has evolved from being a symptomatic aspect of disease associated with the prostate or bladder to a form of lower urinary tract disorder. However, recent advances in circadian biology and sleep science suggest that it might be important to consider nocturia as a form of circadian dysfunction. In the current review, nocturia is reexamined with an introduction to sleep disorders and recent findings in circadian biology in an attempt to highlight the importance of rediscovering nocturia as a problem of chronobiology.

Sleep Apnea and Circadian Extracellular Fluid Change as Independent Factors for Nocturnal Polyuria

PURPOSE

We investigated the relationships among nocturnal polyuria, sleep apnea and body fluid volume to elucidate the pathophysiology of nocturia in sleep apnea syndrome.

MATERIALS AND METHODS

We enrolled 104 consecutive patients who underwent polysomnography for suspected sleep apnea syndrome. Self-assessed symptom questionnaires were administered to evaluate sleep disorder and lower urinary tract symptoms, including nocturia. Voiding frequency and voided volume were recorded using a 24-hour frequency-volume chart. Body fluid composition was estimated in the morning and at night using bioelectric impedance analysis. Frequency-volume chart data were analyzed in 22 patients after continuous positive airway pressure therapy.

RESULTS

Patients with nocturnal polyuria showed a higher apnea-hypopnea index (33.9 vs 24.2, p = 0.03) and a larger circadian change in extracellular fluid adjusted to lean body mass (0.22 vs -0.19, p = 0.019) than those without nocturnal polyuria. These relations were more evident in patients 65 years old or older than in those 64 years or younger. A multivariate linear regression model showed an independent relationship of nocturnal polyuria with the apnea-hypopnea index and the circadian change in extracellular fluid adjusted to lean body mass (p = 0.0012 and 0.022, respectively). Continuous positive airway pressure therapy significantly improved nocturnal polyuria and nocturia only in patients with nocturnal polyuria.

CONCLUSIONS

This study identified sleep apnea and the circadian change in extracellular fluid as independent factors for nocturnal polyuria.

Do small differences in hydration status affect mood and mental performance?

Although it has been suggested that many in the general population are dehydrated to the extent that mood and cognition are disrupted, there has been little research investigating mild levels of dehydration. When dehydration reduces body mass by more than 2%, it has been consistently reported that mood is influenced, fatigue is greater, and alertness is lower. In contrast, the effects on cognition have been less consistent. Only a few studies have looked at females and these studies made little attempt to consider hormones that influence kidney functioning. In particular, there has been virtually no attempt to look at changes in hydration status in the range that occurs in individuals with a sedentary lifestyle in a temperate climate. There is a consequent need to study individuals who have lost up to 1% of body mass due to dehydration. While 4 intervention trials have found that the cognition of children improved in response to water consumption, the effects of water consumption on cognition in older adults, another high-risk group, have been largely ignored.

Central control of visceral pain and urinary tract function

Afferent input from Aδ and C-fibres innervating the urinary bladder are processed differently by the brain, and have different roles in signaling bladder sensation. Aδ fibres that signal bladder filling activate a spino-bulbo-spinal loop, which relays in the midbrain periaqueductal grey (PAG) and pontine micturition centre (PMC). The excitability of this circuitry is regulated by tonic GABAergic inhibitory processes. In humans and socialised animals micturition is normally under volitional control and influenced by a host of psychosocial factors. Higher nervous decision-making in a social context to 'go now' or 'do not go' probably resides in frontal cortical areas, which act as a central control switch for micturition. Exposure to psychosocial stress can have profoundly disruptive influence on the process and lead to maladaptive changes in the bladder. During sleeping the voiding reflex threshold appears to be reset to a higher level to promote urinary continence. Under physiological conditions C-fibre bladder afferents are normally silent but are activated in inflammatory bladder states and by intense distending pressure. Following prolonged stimulation visceral nociceptors sensitise, leading to a lowered threshold and heightened sensitivity. In addition, sensitization may occur within the central pain processing circuitry, which outlasts the original nociceptive insult. Visceral nociception may also be influenced by genetic and environmental influences. A period of chronic stress can produce increased sensitivity to visceral pain that lasts for months. Adverse early life events can produce even longer lasting epigenetic changes, which increase the individual's susceptibility to developing visceral pain states in adulthood.

Urodynamic function during sleep-like brain states in urethane anesthetized rats

The aim was to investigate urodynamic parameters and functional excitability of the periaqueductal gray matter (PAG) during changes in sleep-like brain states in urethane anesthetized rats. Simultaneous recordings of detrusor pressure, external urethral sphincter (EUS) electromyogram (EMG), cortical electroencephalogram (EEG), and single-unit activity in the PAG were made during repeated voiding induced by continuous infusion of saline into the bladder. The EEG cycled between synchronized, high-amplitude slow wave activity (SWA) and desynchronized low-amplitude fast activity similar to slow wave and 'activated' sleep-like brain states. During (SWA, 0.5-1.5 Hz synchronized oscillation of the EEG waveform) voiding became more irregular than in the 'activated' brain state (2-5 Hz low-amplitude desynchronized EEG waveform) and detrusor void pressure threshold, void volume threshold and the duration of bursting activity in the external urethral sphincter EMG were raised. The spontaneous firing rate of 23/52 neurons recorded within the caudal PAG and adjacent tegmentum was linked to the EEG state, with the majority of responsive cells (92%) firing more slowly during SWA. Almost a quarter of the cells recorded (12/52) showed phasic changes in firing rate that were linked to the occurrence of voids. Inhibition (n=6), excitation (n=4) or excitation/inhibition (n=2) was seen. The spontaneous firing rate of 83% of the micturition-responsive cells was sensitive to changes in EEG state. In nine of the 12 responsive cells (75%) the responses were reduced during SWA. We propose that during different sleep-like brain states changes in urodynamic properties occur which may be linked to changing excitability of the micturition circuitry in the periaqueductal gray.