Vascular response of the rabbit bladder to chronic partial outlet obstruction

Partial outlet obstruction of the rabbit urinary bladder results, initially, in a rapid increase in bladder mass and remodeling of the bladder wall. Previously, it was shown that this response was characterized by serosal growth (thickening) which was apparent after 1 day of obstruction, before any visible vascularization was observed. After 1 week of obstruction, significant microvessel formation was seen in the transition region between the detrusor smooth muscle and the thickening serosa; after 2 weeks the entire serosa was vascularized.In this study we investigated the effect of chronic (4 week) partial outlet obstruction on microvessel density and distribution in the bladder wall immunohistochemically using CD31 as a marker for vascular endothelium. Transverse sections of bladder wall were examined after 4 weeks of no surgery, sham surgery or partial obstruction.The microvessel density of the obstructed rabbit bladder mucosa and detrusor smooth muscle increased relative to augmentation of these compartments while new vessels appeared in the thickening serosa. Although vessel density did not change with obstruction a significant shift in mean vessel circumference to the left occurred indicating a significant increase in the number of microvessels and small vessels consistent with angiogenesis.     

Prostaglandins and cyclic nucleotides in the urinary bladder of a rabbit model of partial bladder outlet obstruction

Bladder outlet obstruction (BOO) is a common disorder that is associated with altered bladder structure and function. For example, it is well established that BOO results in hypertrophy and hyperplasia of the bladder smooth muscle as well as detrusor instability. Since prostaglandins (PGs) and cyclic nucleotides (cyclic AMP [cAMP] and cyclic GMP [cGMP]) mediate both smooth muscle tone and proliferation, it is reasonable to suggest that changes in their levels may be involved in the pathophysiology of BOO-associated bladder disorders. Hence, the objective of this study was to investigate cyclic AMP, cyclic GMP and prostaglandins in the bladder of a rabbit model of BOO. BOO was induced in adult male New Zealand White rabbits. After 3 weeks, urinary bladders were excised, weighed and cut into segments. They were then incubated with stimulators of PGs, cAMP and cGMP and the formation of PGs, cAMP and cGMP were measured using radioimmunoassays. There was a significant increase in the obstructed bladder weights (P=0.002). The formation of PGE2, PGI2, cAMP and cGMP was significantly diminished in the detrusor (P<0.05) and bladder neck (P<0.05) in the BOO bladders compared to age-matched controls. Since PGE2, PGI2, cAMP and cGMP are known to inhibit the proliferation of smooth muscle cells (SMCs), the decreased synthesis of these factors, in BOO, may play a role in bladder SMC hypertrophy/hyperplasia. Our study points to the possible use of drugs that modulate the NO-cGMP and/or PG-cAMP axes in BOO-associated bladder pathology.     

老年男性脑卒中患者排尿功能障碍的尿动力学评估

目的:存在阻塞性尿路疾患的老年男性在发生脑血管意外后,是否可通过早期症状或排尿症状类型(梗阻性还是刺激性)来预判排尿功能障碍的病因。方法:选择57例脑卒中后主诉排尿障碍的老年男性患者,所有患者均有继发于良性前列腺增生(BPH)的膀胱出口梗阻(BOO)症状。采集病史并行体检,57位患者均实行尿动力学检查,检查结果行A-G图分析并分类为:有梗阻,无梗阻及可疑梗阻。结果:患者平均年龄70岁(54-87),按排尿障碍的主诉类型分组(纯刺激症状42%,纯梗阻症状34%,两者混合24%),其中51例(89%)在脑卒中发生后即出现排尿症状,47(82%)例患者出现逼尿肌反射亢进(DH),在三组患者中无显著统计学差异。压力流率分析显示,36(63%)位患者有出口梗阻,无梗阻14(24%)例,可疑梗阻7(13%)例。在3组患者中亦无显著统计学差异。结论:所有老年男性患者呈现的症状不能预测膀胱出口梗阻或逼尿肌反射亢进的尿动力学结果。中风发生后排尿功能障碍症状的发生率明显升高,表明由脑血管意外引起的排尿功能障碍合并前期具有膀胱出口梗阻疾病时,可能会使后者的症状恶化,反之亦然。     

Detrusor expulsive strength is preserved, but responsiveness to bladder filling and urinary sensitivity is diminished in the aging mouse

The prevalence of urinary symptoms increases with age and is a significant source of distress, morbidity, and expense in the elderly. Recent evidence suggests that symptoms in the aged may result from sensory dysfunction, rather than abnormalities of detrusor performance. Therefore, we employed a pressure/flow multichannel urethane-anesthetized mouse cystometry model to test the hypothesis that in vivo detrusor performance does not degrade with aging. Secondarily, we sought to evaluate sensory responsiveness to volume using pressure-volume data generated during bladder filling. Cystometric data from 2-, 12-, 22-, and 26-mo-old female C57BL6 mice were compared. All 2- and 12-mo-old mice, 66% of 22-mo-old mice, and 50% of 26-mo-old mice responded to continuous bladder filling with periodic reflex voiding. Abdominal wall contraction with voiding had a minimal contribution to expulsive pressure, whereas compliance pressure was a significant contributor. Maximum bladder pressure, estimated detrusor pressure, detrusor impulse (pressure-time integral), as well as indices of detrusor power and work, did not decrease with aging. Bladder precontraction pressures decreased, compliance increased, and nonvoiding contraction counts did not change with increasing age. Intervoid intervals, per-void volumes, and voiding flow rates increased with age. Calculations approximating wall stress during filling suggested loss of bladder volume sensitivity with increasing age. We conclude that aging is associated with an impaired ability to respond to the challenge of continuous bladder filling with cyclic voiding, yet among responsive animals, voiding detrusor contraction strength does not degrade with aging in this murine model. Furthermore, indirect measures suggest that bladder volume sensitivity is diminished. Thus, changes in homeostatic reserve and peripheral and/or central sensory mechanisms may be important contributors to aging-associated changes in bladder function.     

Mir-29 Repression in Bladder Outlet Obstruction Contributes to Matrix Remodeling and Altered Stiffness

Recent work has uncovered a role of the microRNA (miRNA) miR-29 in remodeling of the extracellular matrix. Partial bladder outlet obstruction is a prevalent condition in older men with prostate enlargement that leads to matrix synthesis in the lower urinary tract and increases bladder stiffness. Here we tested the hypothesis that miR-29 is repressed in the bladder in outlet obstruction and that this has an impact on protein synthesis and matrix remodeling leading to increased bladder stiffness. c-Myc, NF-κB and SMAD3, all of which repress miR-29, were activated in the rat detrusor following partial bladder outlet obstruction but at different times. c-Myc and NF-κB activation occurred early after obstruction, and SMAD3 phosphorylation increased later, with a significant elevation at 6 weeks. c-Myc, NF-κB and SMAD3 activation, respectively, correlated with repression of miR-29b and miR-29c at 10 days of obstruction and with repression of miR-29c at 6 weeks. An mRNA microarray analysis showed that the reduction of miR-29 following outlet obstruction was associated with increased levels of miR-29 target mRNAs, including mRNAs for tropoelastin, the matricellular protein Sparc and collagen IV. Outlet obstruction increased protein levels of eight out of eight examined miR-29 targets, including tropoelastin and Sparc. Transfection of human bladder smooth muscle cells with antimiR-29c and miR-29c mimic caused reciprocal changes in target protein levels in vitro. Tamoxifen inducible and smooth muscle-specific deletion of Dicer in mice reduced miR-29 expression and increased tropoelastin and the thickness of the basal lamina surrounding smooth muscle cells in the bladder. It also increased detrusor stiffness independent of outlet obstruction. Taken together, our study supports a model where the combined repressive influences of c-Myc, NF-κB and SMAD3 reduce miR-29 in bladder outlet obstruction, and where the resulting drop in miR-29 contributes to matrix remodeling and altered passive mechanical properties of the detrusor.     

Sleep Cystometrography: A Preliminary Study of Bladder Function During Sleep

Bladder function during sleep was studied by the use of a cystometer which recorded detrusor contractions and intravesical pressure as urine accumulated in the bladder during diuresis. The cystometrographic tracing was obtained while the patient was awake. A detrusor contraction can occur during sleep. Results of such studies on five patients are presented, with photographs of representative cystometrographic tracings.The general pattern of the cystometrogram during sleep was found to be different from that obtained while the patient was awake. A detrusor contraction can occur during sleep and may subsequently: (a) subside without awakening the patient; (b) be associated with the involuntary escape of urine or flatus; or (c) cause the patient to awaken. It is suggested that detrusor contractions rather than increases in urinary volume are responsible for the individual''s awakening at night to urinate.In the light of these observations, further study of patients with enuresis and those with non-obstructive nocturia is required.     

Neurotransmission and viscoelasticity in the ovine fetal bladder after in utero bladder outflow obstruction

Fetal bladder outflow obstruction, predominantly caused by posterior urethral valves, results in significant urinary tract pathology; these lesions are the commonest cause of end-stage renal failure in children, and up to 50% continue to suffer from persistent postnatal bladder dysfunction. To investigate the physiological development of the fetal bladder and the response to urinary flow impairment, we performed partial urethral obstruction and complete urachal ligation in the midgestation fetal sheep for 30 days. By electrical and pharmacological stimulation of bladder strips, we found that muscarinic, purinergic, and nitrergic mechanisms exist in the developing fetal bladder at this gestation. After bladder outflow obstruction, the fetal bladder became hypocontractile, producing less force after nerve-mediated and muscarinic stimulation with suggested denervation, and also exhibited greater atropine resistance. Furthermore, fetal bladder urothelium exerted a negative inotropic effect, partly nitric oxide mediated, that was not present after obstruction. Increased compliance, reduced elasticity, and viscoelasticity were observed in the obstructed fetal bladder, but the proportion of work performed by the elastic component (a physical parameter of extracellular matrix) remained the same. In addition to denervation, hypocontractility may result from a reduction in the elastic modulus that may prevent any extramuscular components from sustaining force produced by detrusor smooth muscle.     

Expression of cyclooxygenase-2 in urinary bladder in rats with cyclophosphamide-induced cystitis

These studies examined the expression of cyclooxygenase-2 (COX-2) expression in the urothelium and suburothelial space and detrusor from rats treated with cyclophosphamide (CYP) to induce acute (4 h), intermediate (48 h), or chronic (10-day) cystitis. Western blot analysis and immunohistochemistry were used to demonstrate COX-2 expression. In whole mount preparations of urinary bladder, nerve fibers in the suburothelial plexus, and inflammatory cell infiltrates were characterized for COX-2 expression after CYP-induced cystitis. COX-2 expression significantly (P 相似文献   

Alpha1 adrenoceptor subtypes in human urinary bladder: sex and regional comparison

A detailed study of the presence of alpha1 AR binding sites and alpha1 AR subtype mRNA expression in human urinary bladder areas involved in the micturition (i.e. detrusor, trigone and neck) is reported here, investigating whether or not there are differences between sexes. Results obtained indicated that alpha1 AR proteins were detectable in each bladder area. In both sexes, the detrusor and the neck expressed similar levels of alpha1 ARs: respectively, detrusor: 14.6 +/- 1.2 in men and 13.1 +/- 1.1 fmol/mg prot in women; neck: 16.9 +/- 3.2 in men and 17.5 +/- 4.1 fmol/mg prot in women. In the trigone, significantly higher alpha1ARs were found in women compared to men (20.6 +/- 1.1 vs 11.7 +/- 0.7 fmol/mg prot). Subtype analysis indicated that in women, each area was endowed with mRNA encoding for each alpha1 AR subtype. The men detrusor expressed alpha1a and alpha1d ARs, while in the trigone and the neck, each subtype was present. Since the detrusor muscle hypertrophy is a marker of bladder obstructive outlet, the selective alpha1 AR subtype targeting arouses much interest, as evidence indicates that there are differences in signalling pathways among the subtypes. Furthermore, the significance of the alpha1 ARs coexpression is still unknown; interestingly, recent papers demonstrate that alpha1 AR subtypes could dimerize. Thus, in the human urinary bladder it may be suggested a potential level of alpha1 AR complexity that could have an impact on drug development.     

Expression of Hsp27 correlated with rat detrusor contraction after acute urinary retention

Heat shock protein 27 (Hsp27) can regulate actin cytoskeleton dynamics and contractile protein activation. This study investigates whether Hsp27 expression is related to bladder contractile dysfunction after acute urinary retention (AUR). Female rats were randomized either to AUR by urethral ligation or to normal control group. Bladder and smooth muscle strip contraction at time points from 0 h to 7 days after AUR were estimated by cystometric and organ bath studies. Hsp27 expression in bladder tissue at each time point was detected with immunofluorescence, Western blots, and real-time PCR. Expression of the three phosphorylated forms of Hsp27 was detected by Western blots. Smooth muscle ultrastructure was observed by transmission electron microscopy. Data suggest that maximum detrusor pressure and both carbachol-induced and spontaneous detrusor strip contraction amplitude decreased gradually for the duration from 0 to 6 h, and then increased gradually to near-normal values at 24 h. Treatment of muscle strips with the p38MAK inhibitor, SB203580, inhibited carbachol-induced contractions. Smooth muscle ultrastructure damage was the highest at 6 h after AUR, and then lessened gradually during next 7 days, and ultrastructure was close to normal. Expressions of Hsp27 mRNA and protein and the proteins of the three phosphorylated forms were higher at 0 h, decreased to lower levels up to 6 h, and then gradually increased. Therefore, we conclude that rat bladder contractile function after AUR worsens during 0–6 h, and then gradually recovers. The findings of the current study suggest that Hsp27 modulates bladder smooth muscle contraction after AUR, and that phosphorylation of Hsp27 may be an important pathway modulating actin cytoskeleton dynamics in bladder smooth muscle contraction and reconstruction after injury.     

脑桥上中枢损伤与腰骶段脊髓损伤患者的膀胱功能障碍及尿动力特点研究

目的:比较脑桥以上中枢损伤与腰骶段脊髓损伤患者的膀胱功能障碍及尿动力学特点。方法:回顾性分析2011年3月至2014年5月我院收治的78例中枢神经损伤患者的临床资料,包括临床表现、诊断、排尿方式、残余尿、尿动力学检查结果。其中,脑桥以上中枢损伤组43例,腰骶段脊髓损伤组35例,分析和比较两组患者的自由尿流率参数和完全膀胱测压参数。结果:两组间的最大尿流率、排尿量比较差异无统计学意义(P0.05),脑桥上中枢损伤组的残余尿量明显低于腰骶段脊髓损伤组,差异有统计学意义(P0.05)。与腰骶段脊髓损伤组比较,脑桥以上损伤组的膀胱容量明显减少,最大尿流率时的压力、逼尿肌的最大压力及平均压力明显增加,差异均有统计学意义(P0.05)。两组膀胱的顺应性、逼尿肌稳定性比较差异有统计学意义(P0.05),脑桥以上中枢损伤患者的多数表现为低顺应性膀胱(27/43),胸腰段脊髓损伤患者主要表现为高顺应性膀胱(21/35);脑桥以上损伤组多表现为逼尿肌的过度活动(29/43),而腰骶段脊髓损伤组更多表现为逼尿肌的无反射和弱反射(20/35)。结论:脑桥以上损伤患者主要表现为逼尿肌过度活动和膀胱容量的显著降低,以低顺应性膀胱为主;腰骶段脊髓损伤患者的逼尿肌多为无反射和弱反射,以高顺应性膀胱为主。     

Effect of Ca2+ antagonists on isolated rabbit detrusor muscle.

Ca(2+)-antagonists change the contractility of isolated detrusor smooth muscle of rabbit influencing the translocation of intra- and extra-cellular Ca2+. This observation might be of clinical importance in the treatment of disorders of urinary bladder function. During field stimulation of different segments of isolated rabbit bladder it was found that the specific Ca(2+)-antagonist nifedipine and verapamil and the non-selective Ca(2+)-antagonist fendiline, prenylamine and cinnarizine blocked the contractions induced by field stimulus to different extent, which decreased from the bladder towards the bladder base (fundus). The highest rate of blocking effect was produced by nifedipine followed by verapamil, prenylamine and fendiline, respectively. Cinnarizine exerted the lowest effect. The change in amplitude and frequency of spontaneous peristalsis was similar in its tendency to the blockade of the field stimulus induced contraction.     

Essential Elements as Biomarkers of Acute Kidney Injury and Spontaneous Reversion

Acute kidney injury (AKI) is an important health problem and can be caused by number of factors. The use of aminoglycosides, such as gentamicin, is one of these factors. Recently, an effort has been made to find biomarkers to guide treatment protocols. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to estimate the contents of Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn in serum and urine of the healthy, AKI, and spontaneous recovery (SR) groups of animals. The animal model of AKI and SR was validated by measuring serum and urinary urea and creatinine. The quantitative determination of the elements showed a decrease in serum levels of Ca, and Fe in the AKI group (P<0.01 vs. healthy), with a return to normal levels in the SR group, without a significant difference between the healthy and SR groups. In the urine samples, there was a decrease in P and Na levels in the AKI group (P<0.001 and P<0.01 vs. healthy), but Ca levels were increased in this group compared with the healthy and SR groups (P<0.01). These findings indicate that mineral elements might be useful as biomarkers for AKI.     

Aging impairs neurogenic contraction in guinea pig urinary bladder: role of oxidative stress and melatonin

The incidence of urinary bladder disturbances increases with age, and free radical accumulation has been proposed as a causal factor. Here we investigated the association between changes in bladder neuromuscular function and oxidative stress in aging and the possible benefits of melatonin treatment. Neuromuscular function was assessed by electrical field stimulation (EFS) of isolated guinea pig detrusor strips from adult and aged female guinea pigs. A group of adult and aged animals were treated with 2.5 mg x kg(-1) x day(-1) melatonin for 28 days. Neurotransmitter blockers were used to dissect pharmacologically the EFS-elicited contractile response. EFS induced a neurogenic and frequency-dependent contraction that was impaired by aging. This impairment is in part related to a decrease in detrusor myogenic contractility. Age also decreased the sensitivity of the contraction to pharmacological blockade of purinergic and sensitive fibers but increased the effect of blockade of nitrergic and adrenergic nerves. The density of cholinergic and nitrergic nerves remained unaltered, but aging modified afferent fibers. These changes were associated with an increased level of markers for oxidative stress. Melatonin treatment normalized oxidative levels and counteracted the aging-associated changes in bladder neuromuscular function. In conclusion, these results show that aging modifies neurogenic contraction and the functional profile of the urinary bladder plexus and simultaneously increases the oxidative damage to the organ. Melatonin reduces oxidative stress and improves the age-induced changes in bladder neuromuscular function, which could be of importance in reducing the impact of age-related bladder disorders.     

原发性高血压对良性前列腺增生病程发展的影响研究

目的：探讨原发性高血压与良性前列腺增生（BPH）发生与-临床进展的相关性。方法：将确诊为良性前列腺增生的78例BPH患者分为单纯性BPH组和BPH合并有高血压组两组,其中BPH组33例,BPH合并有高血压组45例。对两组患者的尿流率、残尿量、血清前列腺特异性抗原（PSA）、血尿发生率、前列腺体积、国际前列腺症状（tPSS）评分、尿潴留次数及不稳定膀胱发生率指标进行对比分析。结果：两组患者间在年龄、尿流率、残尿量、PSA、最大膀胱容量及最大逼尿肌压力指标差异无统计学意义（P〉0．05）。而BPH合并高血压患者在血尿发生率、前列腺体积、IPSS评分、尿潴留次数及不稳定膀胱发生率指标上明显大于单纯良性前列腺增生组,差异有统计学意义（P〈0．05）。结论：原发性高血压患者发生前列腺增生的病例报道越来越多,高血压状态能够促进BPH的发生以及临床进展。     

Estrogen modulates the expression of myosin heavy chain in detrusor smooth muscle

The effect of low serum estrogen levels on urinary bladder function remains poorly understood. Using a rabbit model, we analyzed the effects of estrogen on the expression of the isoforms of myosin, the molecular motor for muscle contraction, in detrusor smooth muscle. Expression of myosin heavy chain (MHC) isoforms, which differ in the COOH-terminal (SM1 and SM2) and the NH(2)-terminal (SM-A and SM-B) regions as a result of alternative splicing of the mRNA at either the 3'- or 5'-ends, was analyzed in age-matched female rabbits that were sham operated, ovariectomized (Ovx), and given estrogen after ovariectomy (4 rabbits/group). Ovx rabbits showed a significant decrease in the overall MHC content per gram of wet detrusor smooth muscle compared with controls (P < 0.04), which was reversed by estrogen replacement (P < 0.02). MHC content, as a proportion of total milligram of protein in the bladder tissue extracted, was also increased in estrogen-treated Ovx rabbits. Quantitative competitive RT-PCR revealed 1.72-, 2.63-, and 5.82 x 10(6) copies of MHC mRNA/100 ng total mRNA in Ovx, control, and estrogen-treated rabbits, respectively (P < 0.01). RT-PCR analysis using oligonucleotides specific for the region containing the SM1/SM2 MHC alternative splice sites indicated a lower SM2-to-SM1 ratio in estrogen-treated compared with control and Ovx rabbits (P < 0.05). Similarly, SDS-PAGE analysis of extracted myosin from estrogen-treated rabbits revealed a significantly lower SM2-to-SM1 isoform ratio compared with control and Ovx rabbits (P < 0.05). Expression of the SM-A and SM-B isoforms was not affected. These results indicate that myosin content is increased upon estrogen replacement in Ovx rabbits and that the abundance of SM1 relative to SM2 is greater in estrogen-treated rabbits compared with normal and Ovx rabbits. These data suggest that estrogen affects alternative splicing at the 3'-end of the MHC pre-mRNA to increase the proportion of SM1 vs. SM2.     

Smooth muscle trans-membrane sarcoglycan complex in partial bladder outlet obstruction

The urinary bladder experiences both distension and contraction as a part of the normal filling and emptying cycle. To empty properly, tension generated intracellularly in a smooth muscle cell must be smoothly and efficiently transferred across its sarcolemma to the basement membrane, which mediates its binding to both the extracellular matrix and to other cells. As a consequence of urethral obstruction, the bladder cannot generate appropriate force to contract the organ, thereby leading to inefficient emptying and associated sequelae. In this study, an animal model of urethral obstruction was utilized to study the membrane-associated structures that transfer tension across the sarcolemma of bladder smooth muscle cells. Immunohistochemical localization of key components of the smooth muscle tension transfer apparatus (TTA) was performed utilizing specific antibodies against:(1) the α-chains of type IV collagen, a basement membrane component, and (2) β-sarcoglycan, an integral membrane protein that is a participant in the physical linkage between the cytoskeleton and the basement membrane. We demonstrate, in obstructed animals, that there is a pronounced disruption of the TTA with a physical displacement of these two components that can be demonstrated at the level of the light microscope using scanning confocal microscopy. Electron microscopy further demonstrates significant increases in the size of the junctional plaques between smooth muscle cells.