Functional Anatomy: Urology
Qualitative and quantitative expression profile of muscarinic receptors in human urothelium and detrusor.
Tyagi S, Tyagi P, Van-le S, Yoshimura N, Chancellor MB, de Miguel F
J Urol. 2006 Oct;176(4):1673-8.
PURPOSE: We compared the complete spectrum of receptor subtypes expressed by human detrusor and its primary culture with the expression profile in a human urothelium immortalized cell line, and in fresh urothelium tissue and its primary cell culture. MATERIALS AND METHODS: The levels of mRNA expressed for receptor subtypes M(1) through M(5) were determined with reverse transcriptase-polymerase chain reaction and quantitative polymerase chain reaction in total RNA extracted individually from different human bladder specimens, including fresh tissue of human urothelium and detrusor, and their respective primary cultures, as well as from the UROtsa cell line. RESULTS: All 5 muscarinic receptors were detected in fresh human bladder tissue by reverse transcriptase-polymerase chain reaction RNA. The same was true in separated urothelium and detrusor tissue except for the lack of the M(5) receptor transcript. Receptor subtype mRNA expression in the UROtsa cell line paralleled expression in fresh human bladder. Quantitative polymerase chain reaction data further corroborated these results and showed comparable mRNA expression for M(2) and M(3) in primary detrusor cultures. Primary cultures also had a decreased copy number of receptor genes than native tissue. The decrease was even more pronounced in primary urothelium culture and the UROtsa cell line in the presence of high calcium. M(2) and M(3) receptors were also detected in urothelium and detrusor by immunoreactivity. CONCLUSIONS: We identified all 5 existing muscarinic receptor subtypes in detrusor and urothelium, and transcripts levels of M(2) and M(3) were comparable in detrusor. These results support an alternative site of action in urothelium for anti-muscarinic drugs. Urothelial receptors should be considered in the design of future drugs for overactive bladder.
Time-dependent variations in inflammation and scar formation of six different pubovaginal sling materials in the rabbit model.
Krambeck AE, Dora CD, Sebo TJ, Rohlinger AL, DiMarco DS, Elliott DS
Urology. 2006 May;67(5):1105-10.
OBJECTIVES: To provide pathologic evidence, using six different sling materials, of the findings from rabbit model studies demonstrating loss of tensile strength and stiffness in porcine and cadaveric sling materials. METHODS: Ten rabbits randomized into two survival groups (6 and 12 weeks of age) each had human cadaveric fascia, porcine dermis, porcine small intestine submucosa, polypropylene mesh, and autologous fascia implanted on their anterior rectus fascia. At harvest, hematoxylin-eosin and immunohistochemical staining for CD3, CD20, and MIB-I were performed. A pathologist unaware of the content of the slides quantified the degree of inflammation and fibrosis of each. RESULTS: Significant differences were found for inflammation (P = 0.016), eosinophil infiltrate (P = 0.035), and inflammatory rind (P = 0.027) at 12 weeks, with polypropylene mesh having the lowest degree. At 12 weeks, differences were found in the presence of fibrosis/scar formation (P = 0.010) and degree of fibrosis/scar (P = 0.009). Although polypropylene mesh, cadaveric fascia, and porcine dermis all demonstrated a high presence of fibrosis/scar, polypropylene mesh had the greatest overall degree of scar formation at 12 weeks. CONCLUSIONS: The inflammation with the cadaveric fascia and porcine materials may cause rapid clinical deterioration compared with autologous fascia and polypropylene mesh. These data provide a possible explanation for prior biomechanical studies demonstrating variations in tensile strength and stiffness of the different materials. The fibrosis and scarring noted with polypropylene mesh may also contribute to a more lasting repair.
Functional correlates of Doppler flow study of the female urethral vasculature.
Yang JM, Yang SH, Huang WC
Ultrasound Obstet Gynecol. 2006 Jun 6;.
OBJECTIVES: To examine the effect of individual patient factors (age, parity, body mass index, menstrual cycle, menopause, hormone replacement therapy, bladder neck position and urethral mobility) on the appearance of Doppler flow in urethral vessels, to investigate the association between the Doppler flow parameters and intrinsic urethral function, storage and voiding, and to explore differences in the urethral vasculature between subjects with and without urodynamic stress incontinence (USI). METHODS: Over a 4-year period we prospectively performed imaging studies in 355 women, including 244 who denied any lower urinary tract symptoms within the previous 3 months (Group A) and 111 who had had lower urinary tract symptoms (Group B). Studies included morphologic assessment and Doppler flow investigation of the lower urinary tract. Vascular flow velocity and vessel density in the urethral vasculature were measured. For women in Group B, multichannel urodynamic studies were also performed. RESULTS: The urethral vasculature has five main branches of vessels. Their appearance was not affected by the menstrual cycle or menopause except for those of the anterior vaginal vessel and anterior branch of the middle urethral vessel. Other than that of the posterior urethral vessel, in which there was a correlation with parity, the resistance index (RI) was not affected by individual patient factors. However, there was a correlation between the vascular index (VI) and individual factors such as age (r = -0.336, P = 0.002), body mass index (r = -0.287, P = 0.028), menopause (r = -0.402, P < 0.001), and hormone replacement therapy (r = 0.392, P = 0.027). Only the VI and RI of the posterior urethral vessel correlated significantly with the urethral pressure profile. In subjects with lower urinary tract symptoms, the appearance of the urethral vasculature on power Doppler imaging and the corresponding RI and VI values were not correlated with objective evidence of USI. CONCLUSION: Patient factors may affect specific Doppler flow parameters of the urethral vasculature, which are related to intrinsic resting urethral closure. There is no difference in the appearance of the urethral vasculature in subjects with or without USI. Copyright (c) 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Cysteinyl leukotriene d(4) increases human detrusor muscle responsiveness to histamine.
Bouchelouche K, Bouchelouche P
J Urol. 2006 Jul;176(1):361-6.
PURPOSE: Leukotriene D(4) and histamine are proinflammatory mediators that are released concomitantly by activated mast cells. There is the possibility of mutual potentiation of their actions in inflammatory diseases such as interstitial cystitis. We investigated whether human detrusor smooth muscle cells showed increased responsiveness to histamine in the presence of leukotriene D(4). MATERIALS AND METHODS: Cold cup detrusor biopsies were obtained from patients undergoing cystoscopy for benign noninvasive bladder diseases. Human detrusor smooth muscle cells in culture were obtained using an explantation technique and subcultivated for a maximum of 3 passages. The cytosolic free Ca(2+) concentration and contractile force were measured by spectrofluorometry and myograph techniques, respectively. RESULTS: Low doses of leukotriene D(4) (10 nM or less), which usually do not produce a significant effect on the free Ca(2+) concentration or on muscle contraction when administered 30 to 60 seconds beforehand, significantly enhanced the transient increase in the free Ca(2+) concentration and isometric force induced by 50 to 200 nM histamine. Increased histamine responses were associated with an upward shift in the fura-2 fluorescence ratio, suggesting that histamine hyperresponsiveness was due to the appearance of additional histamine receptors on the sarcolemma or to more efficient signaling per receptor. Leukotriene D(4) concentrations greater than 10 nM had no potentiating effects. CONCLUSIONS: To our knowledge this is the first demonstration in the human detrusor that leukotriene D(4) potentiates the effect of histamine. These inflammatory mediators, which are often released concomitantly from mast cells, may interact mutually to potentiate the spasmogenic effect of histamine. These results suggest that the combination of leukotriene D(4) and histamine H1 receptor antagonists may be more effective for the treatment of interstitial cystitis than when given alone.
Systemic Nitric Oxide Augmentation Leads to a Rapid Decrease of the Bladder Outlet Resistance in Healthy Men.
Muntener M, Schurch B, Wefer B, Reitz A
Eur Urol. 2006 Mar 6;.
OBJECTIVE: We examined the immediate effect of a systemic nitric oxide augmentation on the bladder outlet resistance in healthy men. METHODS: Eleven healthy male volunteers with a mean age of 25.5 yr were included in the study. They were prepared for a standard urodynamic study, and a baseline pressure-flow study was obtained. The subjects were then given 20mg isosorbide dinitrate sublingually, and after refilling their bladder a second pressure-flow study was done after 20min. The pressure-flow studies were then compared in regard to the average flow rate, the average detrusor pressure during micturition, and the detrusor pressure at maximum flow rate. RESULTS: One of the subjects was unable to void and had to be excluded from the study. In the remaining 10 men, the mean average flow rate increased from 16.7ml/s before to 20.2ml/s after the intake of the NO donor (P=0.013). Concomitantly, the average detrusor pressure during micturition decreased from a mean of 57 to 52cm H(2)O (P=0.004) and the mean detrusor pressure at maximum flow rate decreased from 60 to 52cm H(2)O (P=0.013). CONCLUSIONS: Systemic NO augmentation can lower the functional bladder outlet resistance very rapidly in men. Our results support the concept that the NO-cGMP pathway may be a promising target for medical treatment of lower urinary tract symptoms.
Histomorphology of canine urethral sphincter systems, including three-dimensional reconstruction and magnetic resonance imaging.
Stolzenburg JU, Neuhaus J, Liatsikos EN, Schwalenberg T, Ludewig E, Ganzer R
Urology. 2006 Mar;67(3):624-30.
OBJECTIVES: To present a detailed anatomic description and comparison of the smooth and striated urethral sphincter in male and female dogs. We performed a thorough histologic evaluation, three-dimensional reconstruction, and magnetic resonance imaging of the lower urinary tract of male and female dogs. METHODS: The lower urinary tract anatomy was investigated in 16 male and 18 female dogs by serial sectioning, including immunohistochemical staining and three-dimensional reconstruction. Magnetic resonance imaging performed in 5 male and 5 female dogs before histologic investigation helped to demonstrate the anatomy in vivo. RESULTS: A urethral sphincter muscle in both sexes existed without muscular connection to the pelvic floor. It ran circularly and consisted of an inner smooth and outer striated muscular part. In the female dog, the striated muscle encircled the urethra and vagina in the caudal third of the membranous urethra (musculus urethrovaginalis). A urinary diaphragm (diaphragma urogenitale) could not be found histologically or by magnetic resonance imaging. CONCLUSIONS: The dog is a suitable animal model for investigations of the urethral sphincter. In the female dog, attention should be given to the special topography of the musculus urethrovaginalis.
A uretheral afferent mediated excitatory bladder reflex exists in humans.
J Urol. 2004 Dec;172(6 Pt 1):2498.
Signal transduction underlying carbachol-induced contraction of human urinary bladder.
J Urol. 2004 Dec;172(6 Pt 1):2497.
Acute Alterations in Biochemistry, Morphology and Contractility of Rat Isolated Urinary Bladder via Increased Intra-Abdominal Pressure.
Unsal MA, Imamoglu M, Cay A, Kadioglu M, Aydin S, Ulku C, Kesim M, Alver A, Bozkaya H
Gynecol Obstet Invest. 2006 Feb 4;61(4):179-187.
Objective: To determine the acute effects of increased intra-abdominal pressure (IAP) on the biochemistry, morphology and contractility of the rat isolated urinary bladder using an experimental laparoscopy model. Methods: We divided 24 adult female Sprague-Dawley rats into three groups. The control group (group I) was not subjected to increased IAP. In groups II and III, IAPs of 10 and 20 mm Hg, respectively, were established by carbon dioxide pneumoperitoneum for 60 min. Thirty minutes after desufflation, the rat urinary bladder dome was removed for in vitro pharmacological investigation, measurement of malondialdehyde (MDA) levels and histopathological examination. Statistical comparisons between groups were performed. Results: Tissue MDA levels in groups II and III were significantly higher than in the control group. In group II, only the lamina propria was significantly damaged. However, the epithelium, lamina propria, and serosa were significantly damaged in group III. Acetylcholine potentiated contractions in both IAP groups. Increased responses to electrical field stimulation in the IAP groups were significant only in group II. Conclusions: In this experimental model, 10 and 20 mm Hg of IAP induced by pneumoperitoneum increased MDA levels and caused important changes in the morphology and contractile response of the urinary bladder.
Characterization of thalamic neuronal responses to urinary bladder distention, including the effect of acute spinal lesions in the rat.
Robbins MT, Uzzell TW, Aly S, Ness TJ
J Pain. 2006 Mar;7(3):218-24.
Chronic visceral pain has proved to be difficult to treat. This study characterized urinary bladder distention (UBD)-evoked responses of neurons located within the ventrobasal group of the thalamus. Units were also characterized for responses to cutaneous stimuli and colorectal distention (CRD). In addition, the effects of spinal lesions on UBD-evoked responses were examined in a subset of neurons. After a stable response to UBD was established, 3 sequential lesions of the spinal cord at the mid-cervical level were performed, and responses to UBD were determined 1 and 5 minutes later. A majority of the neurons in the ventrobasal group of the thalamus were excited by UBD, demonstrated graded responses to graded distention pressures, and responded to cutaneous stimulation. No correlation between the magnitude of the responses of thalamic neurons to UBD and CRD was found. UBD-evoked thalamic neuronal activity was significantly attenuated after dorsal midline lesions of the spinal cord. The present study is a quantitative description of ventrobasal thalamic neuronal responses to UBD in the rat and provides direct neurophysiologic evidence that nociceptive information from the urinary bladder to the ventrobasal group of the thalamus ascends via a dorsal midline pathway. PERSPECTIVE: The effect of dorsal midline lesions is of profound clinical interest because it points to a potential treatment for urinary bladder pain, such as that which is characteristic of interstitial cystitis. Further research might reveal pharmacologic approaches to modulate this pain pathway and result in novel treatments for interstitial cystitis.
Closed loop electrical control of urinary continence.
Wenzel BJ, Boggs JW, Gustafson KJ, Grill WM
J Urol. 2006 Apr;175(4):1559-63.
PURPOSE: Individuals with spinal cord injury or neurological disorders may have neurogenic detrusor contractions at low volumes (bladder hyperreflexia), which cause incontinence and can lead to significant health problems. Bladder contractions can be suppressed by electrical stimulation of inhibitory pathways but continuous activation may lead to habituation of the inhibitory reflex and loss of continence. We determined whether conditional stimulation with electrical stimulation of inhibitory pathways applied only at the onset of nascent bladder contractions allows the bladder to fill to a greater volume before continence is lost compared with continuous stimulation. MATERIALS AND METHODS: In 6 alpha-chloralose anesthetized cats cystometry was performed to compare the volume at which continence was lost under the conditions of no stimulation, continuous stimulation and conditional electrical stimulation of inhibitory pathways. PNT ENG was used to detect the onset of bladder contractions and it served as the input to an event triggered control system that regulated conditional stimulation to maintain continence. RESULTS: Conditional stimulation controlled by PNT ENG increased bladder capacity by 36% over no stimulation and by 15% over continuous stimulation (p <0.001 and 0.027, respectively). The event triggered control system decreased stimulation time by 67% compared to continuous stimulation. CONCLUSIONS: Conditional electrical stimulation of inhibitory pathways is more effective than continuous stimulation. A control system triggered by PNT ENG can maintain urinary continence.
Macrophage Migration Inhibitory Factor is Increased in the Urine of Patients With Urinary Tract Infection: Macrophage Migration Inhibitory Factor-Protein Complexes in Human Urine.
Meyer-Siegler KL, Iczkowski KA, Vera PL
J Urol. 2006 Apr;175(4):1523-8.
PURPOSE: MIF is a proinflammatory cytokine present in preformed stores in human urothelium. In animal models of bladder inflammation, including bacterial cystitis, MIF is up-regulated in the bladder and released from the bladder as a high molecular weight complex. We compared urine MIF amounts in patients with UTI to that in patients without UTI, and we examined and identified MIF-protein complexes in urine. MATERIALS AND METHODS: Using enzyme-linked immunosorbent assay we compared MIF levels in the urine of 14 patients with UTI to levels in 16 controls with no UTI. Western blotting under native, denaturing and reducing conditions was done to examine MIF complexes found in urine. Mass spectrometry identified MIF associated proteins in urine, while co-immunoprecipitation confirmed the associations. RESULTS: Mean urine MIF amounts +/- SEM determined by enzyme-linked immunosorbent assay were significantly greater in 14 patients with UTI compared to that in 16 controls (1.96 +/- 0.40 vs 0.59 +/- 0.09 ng/mg creatinine, p <0.01). Western blotting under denaturing conditions showed several high molecular weight complexes (100 to 165 kDa) that increased in UTI urine as well as typical, monomeric MIF (12 kDa). Mass spectrometry identified associated MIF proteins, including ceruloplasmin, albumin and uromodulin. Co-immunoprecipitation confirmed mass spectrometry findings and also identified MIF interaction with alpha-2-macroglobulin. CONCLUSIONS: Increased urine MIF amounts in patients with bacterial cystitis support our experimental evidence showing a role for MIF in pelvic visceral inflammation. The novel finding of an association of MIF with other urine proteins suggest that the physiologically relevant form of MIF may be an MIF-protein complex.
Activation of alpha1D adrenergic receptors in the rat urothelium facilitates the micturition reflex.
Ishihama H, Momota Y, Yanase H, Wang X, de Groat WC, Kawatani M
J Urol. 2006 Jan;175(1):358-64.
PURPOSE: Previous studies have revealed that the activation of alpha(1) adrenergic receptors in urothelial cells releases neurotransmitters. We determined if alpha(1D) adrenergic receptors are expressed in the urothelium of the rat bladder and if inhibition of these receptors affects reflex voiding. MATERIALS AND METHODS: Female Wistar rats were used in the experiments. Receptor expression was evaluated by Western blot. The effects of receptor activation were studied using cystometrograms, measurement of adenosine triphosphate concentrations in the bladder lumen and afferent nerve recording. The alpha(1D) antagonist naftopidil (0.75 to 1.66 mg/kg) was administered intravenously into the external jugular vein. RESULTS: The expression of alpha(1D) adrenergic receptors was detected in urothelial tissue with Western blot and immunohistochemistry. The alpha(1D) receptor antagonist naftopidil prolonged the intercontraction interval during continuous infusion cystometrograms in conscious rats (143% of the control value) and suppressed the excitatory effect of intravesical infusion of acetic acid (0.1%) on the intercontraction interval (220%). Naftopidil inhibited the bladder afferent nerve activity induced by bladder distention (32.0%) and acetic acid infusion (30.4%), and decreased adenosine triphosphate levels in the bladder perfusate during bladder distention (36.6%). CONCLUSIONS: Endogenous catecholamines appear to act on alpha(1D) receptors in the urothelium to facilitate mechanosensitive bladder afferent nerve activity and reflex voiding.
Central muscarinic receptor subtypes regulating voiding in rats.
Kono M, Nakamura Y, Ishiura Y, Komatsu K, Kontani H, Namiki M
J Urol. 2006 Jan;175(1):353-7.
PURPOSE: Muscarinic receptors are distributed widely in the brain. A recent study revealed that central muscarinic receptors are involved in voiding regulation. However, to our knowledge the role of each muscarinic receptor subtype has not been resolved. Therefore, we evaluated the effect of intracerebroventricular administration of selective muscarinic M1 to M4 receptor antagonists on voiding function in rats. MATERIALS AND METHODS: Female Sprague-Dawley rats were cannulated for intracerebroventricular infusion under halothane anesthesia. In experiment 1 cystometry was performed in conscious rats, and BC and maximal voiding pressure were measured. In experiment 2 a catheter was inserted via the bladder dome to the bladder neck and UPP was measured by saline infusion. Repeat cystostomy was performed, and saline infusion and discharge saline, BC, maximal IVP and minimal UPP were measured in conscious rats. Pirenzepine, methoctramine, pFHHSiD and MT-3 were used as selective M1, M2, M3 and M4 muscarinic receptor antagonists, respectively, which were injected intracerebroventricularly. RESULTS: In experiment 1 pirenzepine and pFHHSiD increased BC and decreased maximal voiding pressure. Methoctramine and MT-3 decreased BC. In experiment 2 pirenzepine and pFHHSiD increased BC and minimal UPP, and decreased maximal IVP. Methoctramine and MT-3 decreased BC and maximal IVP. Minimal UPP remained unchanged. CONCLUSIONS: Intracerebroventricular administration of muscarinic M1 and M3 receptor antagonists inhibited urination in conscious rats, while M2 and M4 receptor antagonists induced excitatory changes.