Manabu Kamiyama

Diagnosis and treatment of voiding symptoms.

Lower urinary tract symptoms (LUTS) are associated with lower urinary tract dysfunction. Symptoms are the subjective indicator of a disease or change in condition as perceived by the patient, caregiver, or partner and may lead the individual to seek help from health care professionals. LUTS are usually qualitative and, therefore, cannot usually be used to make a definitive diagnosis. LUTS also can indicate pathologies other than lower urinary tract dysfunction, such as urinary infection. LUTS are divided into 7 groups: storage, voiding (obstructive), postmicturition symptoms and 4 others. Voiding symptoms, which are caused by lower urinary tract obstruction, include slow stream, splitting or spraying, intermittency, hesitancy, straining, and terminal dribble. Postmicturition symptoms, which are experienced immediately after micturition, consist of the feeling of incomplete emptying and postmicturition dribble. Postmicturition dribble describes the involuntary loss of urine immediately after the individual has finished passing urine; in men, usually after leaving the toilet and in women, after rising from the toilet. Hence, postmicturition dribble is elicited by different situations or is considered as having different implications. For example, although postmicturition dribble usually implies incomplete emptying (voiding symptoms) in elderly men with benign prostatic hyperplasia, postmicturition dribble is often considered as urinary incontinence (a storage symptom) in many patients, even with bladder outlet obstruction. In such cases, detailed history taking and further evaluation, such as urinary flowmetry, postvoid residual volume, and comprehensive urodynamic evaluation, should be performed as appropriate. If no urodynamic abnormalities of either the detrusor or the outlet can be detected despite significant LUTS, factors unrelated to the lower urinary tract may be responsible for the voiding symptoms.

Connexin43 hemichannels contributes to the disassembly of cell junctions through modulation of intracellular oxidative status.

Connexin (Cx) hemichannels regulate many cellular processes with little information available regarding their mechanisms. Given that many pathological factors that activate hemichannels also disrupts the integrity of cellular junctions, we speculated a potential participation of hemichannels in the regulation of cell junctions. Here we tested this hypothesis. Exposure of renal tubular epithelial cells to Ca2+-free medium led to disassembly of tight and adherens junctions, as indicated by the reduced level of ZO-1 and cadherin, disorganization of F-actin, and severe drop in transepithelial electric resistance. These changes were preceded by an activation of Cx43 hemichannels, as revealed by extracellular efflux of ATP and intracellular influx of Lucifer Yellow. Inhibition of hemichannels with chemical inhibitors or Cx43 siRNA greatly attenuated the disassembly of cell junctions. Further analysis using fetal fibroblasts derived from Cx43 wide-type (Cx43+/+), heterozygous (Cx43+/-) and knockout (Cx43-/-) littermates showed that Cx43-positive cells (Cx43+/+) exhibited more dramatic changes in cell shape, F-actin, and cadherin in response to Ca2+ depletion, as compared to Cx43-null cells (Cx43-/-). Consistently, these cells had higher level of protein carbonyl modification and phosphorylation, and much stronger activation of P38 and JNK. Hemichannel opening led to extracellular loss of the major antioxidant glutathione (GSH). Supplement of cells with exogenous GSH or inhibition of oxidative sensitive kinases largely prevented the above-mentioned changes. Taken together, our study indicates that Cx43 hemichannels promote the disassembly of cell junctions through regulation of intracellular oxidative status.

Decreased expression of G protein‐coupled receptor kinases in the detrusor smooth muscle of human urinary bladder with outlet obstruction

Aim: We examine the expression of mRNA of G protein‐coupled receptor kinase (GRK) subtypes and muscarinic acetylcholine receptor (M) subtypes in the detrusor smooth muscle of the human urinary bladder. Furthermore, we confirm the presence and the localization of GRK proteins in the detrusor smooth muscle of the obstructed bladder in comparison with the control bladder.

Gene and protein expression profiles of prostaglandin E2 receptor subtypes in the human corpus cavernosum

Prostaglandin E1 leads to penile erection, mainly via prostaglandin E2 (EP) receptors. This study aimed to identify the expression profile of EP receptor genes in human corpus cavernosum. Using the quantitative real-time reverse transcription polymerase chain reaction, the mRNA levels of EP receptor subtypes were measured. In addition, expressions of EP receptor subtype proteins were determined by immunohistochemical method. Among the four subtypes, EP4 receptor mRNA expression was the highest, and EP2 receptor mRNA followed, whereas EP1 and EP3 receptor mRNAs were hardly observed. Expression level of EP4 receptor mRNA was significantly higher than that of EP2 receptor mRNA. Expression of both EP2 and EP4 receptor proteins were clearly detected in the cavernous smooth muscle. These results may suggest that EP4 receptor plays an important role among four EP receptor subtypes for relaxation of smooth muscle in the human corpus cavernosum.

The oscillation of intracellular Ca 2+ influx associated with the circadian expression of Piezo1 and TRPV4 in the bladder urothelium

We previously showed that bladder functions are controlled by clock genes with circadian rhythm. The sensation of bladder fullness (SBF) is sensed by mechano-sensor such as Piezo1 and TRPV4 in the mouse bladder urothelium. However, functional circadian rhythms of such mechano-sensors remain unknown. To investigate functional circadian changes of these mechano-sensors, we measured circadian changes in stretch-evoked intracellular Ca2+ influx ([Ca2+]i) using mouse primary cultured urothelial cells (MPCUCs). Using Ca2+ imaging, stretch-evoked [Ca2+]i was quantified every 4 h in MPCUCs derived from wild-type (WT) and ClockΔ19/Δ19 mice, which showed a nocturia phenotype. Furthermore, a Piezo1 inhibitor GsMTx4 and a TRPV4 inhibitor Ruthenium Red were applied and stretch-evoked [Ca2+]i in MPCUCs was measured to investigate their contribution to SBF. Stretch-evoked [Ca2+]i showed a circadian rhythm in the WT mice. In contrast, ClockΔ19/Δ19 mice showed disrupted circadian rhythm. The administration of both GsMTx4 and Ruthenium Red eliminated the circadian rhythm of stretch-evoked [Ca2+]i in WT mice. We conclude that SBF may have a circadian rhythm, which is created by functional circadian changes of Piezo1 and TRPV4 being controlled by clock genes to be active during wakefulness and inactive during sleep. Abnormalities of clock genes disrupt SBF, and induce nocturia.

AMPK Suppresses Connexin43 Expression in the Bladder and Ameliorates Voiding Dysfunction in Cyclophosphamide-induced Mouse Cystitis.

Bladder voiding dysfunction is closely related to local oxidation, inflammation, and enhanced channel activities. Given that the AMP-activated protein kinase (AMPK) has anti-oxidative, anti-inflammatory and channel-inhibiting properties, we examined whether and how AMPK affected bladder activity. AMPK activation in rat bladder smooth muscle cells (BSMCs) using three different AMPK agonists resulted in a decrease in connexin43 (Cx43) expression and function, which was associated with reduced CREB phosphorylation, Cx43 promoter activity and mRNA expression, but not Cx43 degradation. Downregulation of CREB with siRNA increased Cx43 expression. A functional analysis revealed that AMPK weakened BSMC contraction and bladder capacity. AMPK also counteracted the IL-1β- and TNFα-induced increase in Cx43 in BSMCs. In vivo administration of the AMPK agonist AICAR attenuated cyclophosphamide-initiated bladder oxidation, inflammation, Cx43 expression and voiding dysfunction. Further analysis comparing the responses of the wild-type (Cx43+/+) and heterozygous (Cx43+/−) Cx43 mice to cyclophosphamide revealed that the Cx43+/− mice retained a relatively normal micturition pattern compared to the Cx43+/+ mice. Taken together, our results indicate that AMPK inhibits Cx43 in BSMCs and improves bladder activity under pathological conditions. We propose that strategies that target AMPK can be developed as novel therapeutic approaches for treating bladder dysfunction.

Role of bone scan index in the prognosis and effects of therapy on prostate cancer with bone metastasis: Study design and rationale for the multicenter Prostatic Cancer Registry of Standard Hormonal and Chemotherapy Using Bone Scan Index (PROSTAT-BSI) stu

To present the study design and rationale of Prostatic Cancer Registry of Standard Hormonal and Chemotherapy Using Bone Scan Index, a prospective study aiming to determine the role of the bone scan index, the amount of bone metastasis, in the treatment and prognosis of prostate cancer patients.

The time-dependent variation of ATP release in mouse primary-cultured urothelial cells is regulated by the clock gene

The sensation of bladder fullness (SBF) is triggered by the release of ATP. Therefore, the aim of this study was to investigate whether time‐dependent changes in the levels of stretch‐released ATP in mouse primary‐cultured urothelial cells (MPCUCs) is regulated by circadian rhythm via clock genes.

Carbenoxolone inhibits TRPV4 channel-initiated oxidative urothelial injury and ameliorates cyclophosphamide-induced bladder dysfunction

Carbenoxolone (CBX) is a clinically prescribed drug for the treatment of digestive ulcer and inflammation. It is also a widely used pharmacological inhibitor of several channels in basic research. Given that the overactivity of several channels, including those inhibitable by CBX, underlies bladder dysfunction, we tested the potential therapeutic application and mechanism of CBX in the treatment of voiding dysfunction. In a mouse model of cystitis induced by cyclophosphamide (CYP), CBX administration prevented the CYP‐elicited increase in bladder weight, oedema, haemorrhage, and urothelial injury. CBX also greatly improved micturition pattern, as manifested by the apparently decreased micturition frequency and increased micturition volume. Western blot results showed that CBX suppressed CYP‐induced increase in protein carbonyls, COX‐2, and iNOS. Further analysis using cultured urothelial cells revealed that acrolein, the major metabolite of CYP, caused protein oxidation, p38 activation, and urothelial injury. These effects of acrolein were reproduced by TRPV4 agonists and significantly prevented by antioxidant NAC, p38 inhibitor SB203580, TRPV4 antagonist RN‐1734, and CBX. Further studies showed that CBX potently suppressed TRPV4 agonist‐initiated calcium influx and subsequent cell injury. CBX attenuated CYP‐induced cystitis in vivo and reduced acrolein‐induced cell injury in vitro, through mechanisms involving inhibition of TRPV4 channels and attenuation of the channel‐mediated oxidative stress. CBX might be a promising agent for the treatment of bladder dysfunction.

Persistent Urinary Incontinence After Nephrectomy: A Case of Inverted-Y Ureteral Duplication with Ectopic Ureteral Insertion into the Vagina

Inverted-Y ureteral duplication is one of the rarest anomalies of ureteral branching. We encountered a 20-year-old female patient with persistent incontinence even after nephrectomy for ectopic ureteral insertion into the vagina. She had inverted-Y ureteral duplication between the bladder and vagina, and urine was being transported from the bladder to the vagina. To the best of our knowledge, this is a rare case of inverted-Y ureteral duplication with ectopic ureteral insertion into the vagina as well as the ureter into the bladder, which became apparent due to persistent urinary incontinence even after nephrectomy.