COMPARATIVE MORPHOMETRIC STUDY OF BLADDER DETRUSOR BETWEEN PATIENTS WITH BENIGN PROSTATIC HYPERPLASIA AND CONTROLS

Inhibition of DNA methylation during chronic obstructive bladder disease (COBD) improves function, pathology and expression

Partial bladder outlet obstruction due to prostate hyperplasia or posterior urethral valves, is a widespread cause of urinary dysfunction, patient discomfort and also responsible for immense health care costs. Even after removal or relief of obstruction, the functional and pathologic aspects of obstruction remain as a chronic obstructive bladder disease (COBD). Epigenetic changes, such as DNA methylation, contribute to the persistent character of many chronic diseases, and may be altered in COBD. We tested whether candidate genes and pathways and the pathophysiology of COBD were affected by a hypomethylating agent, decitabine (DAC). COBD was created in female Sprague-Dawley rats by surgical ligation of the urethra for 6 weeks, followed by removal of the suture. Sham ligations were performed by passing the suture behind the urethra. After removal of the obstruction or sham removal, animals were randomized to DAC treatment (1 mg/kg/3-times/week intraperitoneally) or vehicle (normal saline). Bladder function was non-invasively tested using metabolic cages, both one day prior to de-obstruction at 6 weeks and prior to sacrifice at 10 weeks. Residual volume and bladder mass were measured for each bladder. Bladders were examined by immunostaining as well as qPCR. The effects of DNA methyltransferase (DNMT)-3A knockout or overexpression on smooth muscle cell (SMC) function and phenotype were also examined in bladder SMC and ex vivo culture. Residual volumes of the DAC treated group were not significantly different from the NS group. Compared to COBD NS, COBD DAC treatment helped preserve micturition volume with a significant recovery of the voiding efficiency (ratio of the maximum voided volume/maximum bladder capacity) by one third (Fig. 1, p > 0.05). Brain-derived neurotrophic factor (BDNF) variants 1 and 5 were upregulated by COBD and significantly reduced by DAC treatment. Deposition of collagen in the COBD bladder was reduced by DAC, but gross hypertrophy remained. In bladder SMC, DNMT3A overexpression led to a loss of contractile function and phenotype. In bladders, persistently altered by COBD, inhibition of DNA-methylation enhances functional recovery, unlike treatment during partial obstruction, which exacerbates obstructive pathology. The underlying mechanisms may relate to the gene expression changes in BDNF and their effects on signaling in the bladder.

Molecular pathways underlying tissue injuries in the bladder with ketamine cystitis

Ketamine cystitis (KC) is a chronic bladder inflammation leading to urinary urgency, frequency, and pain. The pathogenesis of KC is complicated and involves multiple tissue injuries in the bladder. Recent studies indicated that urothelium disruption, lamina propria fibrosis and inflammation, microvascular injury, neuropathological alterations, and bladder smooth muscle (BSM) abnormalities all contribute to the pathogenesis of KC. Ketamine has been shown to induce these tissue injuries by regulating different signaling pathways. Ketamine can stimulate antiproliferative factor, adenosine triphosphate, and oxidative stress to disrupt urothelium. Lamina propria fibrosis and inflammation are associated with the activation of cyclooxygenase-2, nitric oxide synthase, immunoglobulin E, and transforming growth factor β1. Ketamine contributes to microvascular injury via the N-methyl-D aspartic receptor (NMDAR), and multiple inflammatory and angiogenic factors such as tumor necrosis factor α and vascular endothelial growth factor. For BSM abnormalities, ketamine can depress the protein kinase B, extracellular signal-regulated kinase, Cav1.2, and muscarinic receptor signaling. Elevated purinergic signaling also plays a role in BSM abnormalities. In addition, ketamine affects neuropathological alterations in the bladder by regulating NMDAR- and brain-derived neurotrophic factor-dependent signaling. Inflammatory cells also contribute to neuropathological changes via the secretion of chemical mediators. Clarifying the role and function of these signaling underlying tissue injuries in the bladder with KC can contribute to a better understanding of the pathophysiology of this disease and to the design of effective treatments for KC.

The Role of Apoptosis in Detrusor Contractility

Apoptosis has been found in bladder affected by various types of voiding dysfunction. In animal studies, higher levels of apoptosis were observed in conditions of both detrusor overactivity and underactivity than in normal bladders. However, it has been difficult to establish the exact underlying mechanism of apoptosis in these conditions and to find new therapeutic targets because the causes of voiding dysfunction are diverse and the coexistence of various types of voiding problems is common. Furthermore, the lack of studies of the human detrusor contributes to our incomplete understanding of these issues. Therefore, this revies discuss the role of apoptosis in detrusor contractility based on previous studies.

New mouse model of underactive bladder developed by placement of a metal ring around the bladder neck

OBJECTIVE

To develop a new mouse model of underactive bladder (UAB) caused by chronic bladder outlet obstruction (BOO).

METHODS

BOO was created in 6-week-old male C57BL/6 mice using surgery to loosely place a silver jump ring around the bladder neck of each mouse. Micturition behavior (assessed with a metabolic cage) and cystometry were used to evaluate bladder function at 8 and 16 weeks after BOO. Following completion of the functional studies, the bladders of the mice were excised, weighed, and subjected to histological analysis.

RESULTS

Micturition behavior analysis showed that mice subjected to BOO for 16 weeks had a lower frequency of micturition (7.3 ± 1.1 vs 12.5 ± 3.0 times/d, P < .05) and volume per void (106.0 ± 0.1 vs 133.9 ± 3.2 μL, P < .05) than mice subjected to BOO for 8 weeks. Cystometry revealed that mice subjected to BOO for 16 weeks had lower baseline pressure (8.4 ± 0.6 vs 14.0 ± 0.7 cmH₂ O, P < .01) and micturition pressure (13.9 ± 1.1 vs 42.8 ± 1.7 cmH₂ O, P < .05) than mice subjected to BOO for 8 weeks. BOO caused progressive increases in bladder mass and collagen deposition over time.

CONCLUSIONS

We successfully established a novel mouse model of UAB using surgery to place a silver jump ring loosely on the bladder neck. BOO initially induced bladder overactivity but subsequently resulted in UAB due to deterioration of detrusor smooth muscle contractility and progressive deposition of collagen in the bladder wall.

Correlation between prostate volume measured by ultrasound and detrusor wall thickness in men with benign prostatic hypertrophy

Background:

Benign prostatic hypertrophy (BPH) causes subvesical urinary obstruction in the elderly. It leads to changes in the bladder and upper urinary tract. This may be progressive with subsequent morbidities and mortalities. This study aims at determining the relationship between ultrasound-measured prostate volume and detrusor wall thickness (DWT) in men with BPH.

Materials and Methods:

One hundred and ten patients who met the inclusion criteria and were diagnosed with clinical BPH were enrolled. They had no other identifiable cause of bladder outlet obstruction. The International Prostate Symptoms Score (IPSS), Quality of Life (QOL) score, prostate volume, and DWT were measured. Correlation between prostate volume and DWT was done using SPSS version 20.0 (IBM, SPSS, Chicago, IL, USA). A P-value less than 0.05 was considered significant.

Results:

The mean age of patients was 68.3 ± 10.2 years, with a range of 40–100 years. The mean prostate volume and DWT were 94.2 ± 68.4 cm3 and 5.9 ± 3.0 mm, respectively. Mean QOL was 4.77 ± 1.35. The highest IPSS was 35 and lowest was 2. Nocturia was the major IPSS subscore. There was a positive correlation between prostate volume and DWT in men with BPH (r = 0.37; P = 0.007). This is statistically significant.

Conclusion:

Ultrasound-measured prostate volume correlates positively with DWT in men with BPH. This is statistically significant and is able to determine progression of the disease. Coexisting large prostate volume and thickened detrusor wall are an indicator of disease progression and eventual need for surgical intervention. This prevents renal damage.

Urinary bladder organ hypertrophy is partially regulated by Akt1-mediated protein synthesis pathway

AIMS

The present study aims to investigate the role of Akt in the regulation of urinary bladder organ hypertrophy caused by partial bladder outlet obstruction (pBOO).

MAIN METHODS

Male rats were surgically induced for pBOO. Real-time PCR and western blot were used to examine the levels of mRNA and protein. A phosphoinositide 3-kinase (PI3K) inhibitor LY294002 was used to inhibit the activity of endogenous Akt.

KEY FINDINGS

The urinary bladder developed hypertrophy at 2 weeks of pBOO. The protein but not mRNA levels of type I collagen and α-smooth muscle actin (αSMA) were increased in pBOO bladder when compared to sham control. The phosphorylation (activation) levels of Akt1 (p-Ser⁴⁷³), mammalian target of rapamycin (mTOR), p70S6 kinase (p70S6K), and 4E-BP1 were also increased in pBOO bladder. LY294002 treatment reduced the phosphorylation levels of Akt1 and 4E-BP1, and the protein levels of type I collagen and αSMA in pBOO bladder. The mRNA and protein levels of proliferating cell nuclear antigen (PCNA) were increased in pBOO bladder, and PCNA up-regulation occurred in urothelial not muscular layer. LY294002 treatment had no effect on the mRNA and protein levels of PCNA in pBOO bladder. LY294002 treatment partially reduced the bladder weight caused by pBOO.

SIGNIFICANCE

pBOO-induced urinary bladder hypertrophy is attributable to fibrosis, smooth muscle cellular hypertrophy, and urothelium cell hyper-proliferation. Akt1-mediated protein synthesis in pBOO bladder contributes to type I collagen and αSMA but not PCNA up-regulation. Target of Akt1 is necessary but not sufficient in treatment of urinary bladder hypertrophy following pBOO.

Progressive bladder remodeling due to bladder outlet obstruction: a systematic review of morphological and molecular evidences in humans

BACKGROUND

Bladder outlet obstruction is a common urological condition. We aimed to summarize available evidences about bladder outlet obstruction-induced molecular and morphological alterations occurring in human bladder.

METHODS

We performed a literature search up to December 2017 including clinical and preclinical basic research studies on humans. The following search terms were combined: angiogenesis, apoptosis, bladder outlet obstruction, collagen, electron microscopy, extracellular matrix, fibrosis, hypoxia, histology, inflammation, innervation, ischemia, pressure, proliferation, remodeling, suburothelium, smooth muscle cells, stretch, urothelium.

RESULTS

We identified 36 relevant studies. A three-stages model of bladder wall remodeling can be hypothesized involving an initial hypertrophy phase, a subsequent compensation phase and a later decompensation. Histological and molecular alterations occur in the following compartments: urothelium, suburothelium, detrusor smooth muscle cells, detrusor extracellular matrix, nerves. Cyclic stretch, increased hydrostatic and cyclic hydrodynamic pressure and hypoxia are stimuli capable of modulating multiple signaling pathways involved in this remodeling process.

CONCLUSIONS

Bladder outlet obstruction leads to progressive bladder tissue remodeling in humans. Multiple signaling pathways are involved.

Collagen content in the bladder of men with LUTS undergoing open prostatectomy: A pilot study

AIMS

To evaluate the collagen content in the bladder wall of men undergoing open prostate surgery.

METHODS

From July 2014 to August 2016, men aged ≥ 50 years, presenting LUTS and undergoing open prostate surgery due to benign prostatic enlargement (BPE) or prostate cancer were prospectively enrolled. Preoperative assessment included validated questionnaires (IPSS and OAB-V8), lower urinary tract ultrasound, and urodynamics. Bladder biopsies were obtained during open prostatectomy for determination of collagen content (sirius red-picric acid stain; polarized light analysis). Collagen to smooth muscle ratio (C/M) in the detrusor was measured and its relationship with preoperative parameters was investigated. The level of significance was P < 0.05.

RESULTS

Thirty-eight consecutive patients were included in this pilot study. Mean age was 66.36 ± 6.44 years and mean IPSS was 11.05 ± 8.72 points. Men diagnosed with diabetes mellitus (DM2) were found to have higher collagen content in the bladder wall when compared to non-diabetic patients (17.71 ± 6.82% vs 12.46 ± 5.2%, respectively; P = 0.024). Reduced bladder compliance was also marker for higher collagen content (P = 0.042). Bladder outlet obstruction (BOO) was not a predictor of increased collagen deposition in the bladder wall (P = 0.75). Patients with PVR ≥ 200 mL showed a higher collagen to smooth muscle ratio in the bladder wall (P = 0.036).

CONCLUSIONS

DM2 and urodynamic parameters, such as increased PVR and reduced bladder compliance, were associated with higher collagen content in the bladder wall of men with LUTS.

Increased detrusor collagen is associated with detrusor overactivity and decreased bladder compliance in men with benign prostatic obstruction

Background

This study aimed to investigate the relationship between detrusor collagen content and urodynamic parameters in men with benign prostatic obstruction.

Material and methods

Nineteen consecutive patients undergoing open prostatectomy for bladder outlet obstruction (BOO) due to benign prostatic hyperplasia (BPH) were evaluated. Urodynamic tests were performed in all patients. BOO and detrusor contractility were assessed with the BOO index (BOOI) and the bladder contractility index (BCI), respectively. A bladder fragment was obtained during prostatectomy. Eight cadaveric organ donors composed the control group. Bladder sections were stained with picrosirius red and hematoxylin-eosin. The collagen to smooth muscle ratio (C/M) in the detrusor was measured and its relationship with urodynamic parameters was investigated.

Results

Seven (36.8%) patients were operated on due to lower urinary tract symptoms and 12 (63.2%) had urinary retention. The mean prostate volume was 128.6 cm³ ± 32.3 cm³, the mean BOOI was 76.4 ± 33.0, and the mean BCI was 116.1 ± 33.7. The mean C/M in BPH patients and controls were 0.43 ± 0.13 and 0.33 ± 0.09, respectively (P = 0.042). A negative correlation was shown between C/M and bladder compliance (r = –0.488, P = 0.043). The C/M was increased in BPH patients with detrusor overactivity (DO) compared to those without DO (0.490 ± 0.110 and 0.360 ± 0.130, respectively; P = 0.030) and also in patients with urinary retention (P = 0.002). No correlation was shown between C/M and maximum cystometric capacity, BOOI, or BCI.

Conclusion

Men with BOO/BPH have increased detrusor collagen content which is associated with decreased bladder compliance, detrusor overactivity, and urinary retention.

Pelvic ultrasound evaluation for benign prostatic hyperplasia: prediction of obstruction

Global improvements in water quality, management of infectious diseases, and other medical therapeutics have resulted in a growing population of healthy aging men. One obligate anatomic consequence of aging for these men is the development of benign prostatic hyperplasia (BPH) with secondary bladder outlet obstruction. Although the voiding symptoms associated with the change in bladder health over time predominantly impact the quality of a man's daily experience, there are also significant medical consequences of BPH that require intervention. It is a challenge to distinguish men who are at risk for these medical consequences from the much larger population of older men with voiding symptoms (lower urinary tract symptoms, LUTS). A variety of national guidelines have been developed to establish a diagnostic paradigm for meeting this challenge, but all suffer from inadequate sensitivity for the early identification of men at risk for permanent bladder injury. It is likely that the application of a thorough pelvic ultrasound designed to identify the pertinent anatomic aspects of both the bladder and prostate will improve the sensitivity of these diagnostic paradigms, with subsequent improvement in the outcomes for men with BPH/LUTS.

Future direction in pharmacotherapy for non-neurogenic male lower urinary tract symptoms

BACKGROUND

The pathophysiology of male lower urinary tract symptoms (LUTS) is highly complex and multifactorial. The shift in perception that LUTS are not sex or organ specific has not been followed by significant innovations regarding the available drug classes.

OBJECTIVE

To review pathophysiologic mechanisms and clinical and experimental data related to the development of new pharmacologic treatments for male LUTS.

EVIDENCE ACQUISITION

The PubMed database was used to identify articles describing experimental and clinical studies of pathophysiologic mechanisms contributing to male LUTS and, supported by them, new pharmacotherapies with clinical or experimental evidence in the field.

EVIDENCE SYNTHESIS

Several pathologic processes (eg, androgen signaling, inflammation, and metabolic factors) and targets (eg, the urothelium, prostate, interstitial cells, detrusor, neurotransmitters, neuromodulators, and receptors) have been implicated in male LUTS. Some newly introduced drugs, such as phosphodiesterase type 5 inhibitors and β3-adrenergic agonists, have just started broad use in clinical practice. Drugs with potential benefit, such as vitamin D3 receptor analogs, gonadotropin-releasing hormone antagonists, cannabinoids, and drugs injected into the prostate, have been evaluated in experimental studies and have progressed to clinical trials. However, safety and efficacy data for these drugs are still scarce. Some compounds with interesting profiles have only been tested in experimental settings (eg, transient receptor potential channel blockers, Rho-kinase inhibitors, purinergic receptor blockers, and endothelin-converting enzyme inhibitors).

CONCLUSIONS

New pathophysiologic mechanisms of male LUTS are described that lead to the continuous development of new pharmacotherapies. To date, few drugs have been added to the current armamentarium, and several are in various phases of clinical or experimental investigation.

Persistent detrusor overactivity in rats after relief of partial urethral obstruction

Detrusor overactivity (DO) persists after prostatectomy in 20% to 25% of patients with benign disease. Assuming that nonvoiding contractions (NVCs) can be used as a surrogate for DO in humans, the rat model of obstruction/deobstruction may allow us to study the pathophysiology of persistent DO after deobstruction. We investigated bladder function, with a special focus on NVCs, in rats by use of a new, modified method of obstruction and deobstruction and compared these results with those obtained by use of the conventional method. Seventy female Sprague-Dawley rats underwent 1) sham operation (n = 10), 2) obstruction by a modified method (Modif-Obs; n = 12), 3) obstruction/deobstruction by the conventional method (Conv-Obs/Deobs; n = 13), or 4) obstruction/deobstruction by the modified method (Modif-Obs/Deobs; n = 35). The Modif-Obs/Deobs animals were divided into subgroups with (DO+) and without (DO-) NVCs. Two weeks after partial urethral obstruction, the animals were deobstructed, and 1 wk later cystometry was performed with recording of intravesical and intra-abdominal pressures. NVCs were shown in all groups: Modif-Obs (80%), Conv-Obs/Deobs (100%), and Modif-Obs/Deobs (40%). In the Modif-Obs/Deobs group, bladder weight and the muscle-to-collagen ratio were higher in DO+ than in DO- rats. The Modif-Obs/Deobs group showed no mortality compared with 25% mortality in the Conv-Obs/Deobs group. The modified method may be more adequate for studying persistent DO after deobstruction, because it resulted in pressure/volume- and DO-related parameters similar to those found in the clinical situation. The persistence of DO after deobstruction may partly be due to irreversible changes in the bladder caused during the period of obstruction.

Rho-kinase, a common final path of various contractile bladder and ureter stimuli

Normal urinary bladder function is based on the proper contraction and relaxation of smooth muscle (SM), which constitutes the majority of the bladder wall. The contraction and relaxation of all SM involves a phosphorylation-dephosphorylation pathway involving the enzymes smooth muscle myosin light chain kinase (SMMLCK) and smooth muscle myosin light chain phosphatase (SMMLCP), respectively. Although originally thought to function just as a passive opposition to SMMLCK-driven SM contraction, it is now clear that SMMLCP activity is under an extremely complex molecular regulation via which SMMLCP inhibition can induce "calcium sensitization." This review provides a thorough summary of the literature regarding the molecular regulation of the SMMLCP with a focus on one of its major inhibitory pathways that is RhoA/Rho-kinase (ROK) including its activation pathways, effector molecules, and its roles in various pathological conditions associated with bladder dysfunction. Newly emerging roles of ROK outside of SM contractility are also discussed. It is concluded that the RhoA/ROK pathway is critical for the maintenance of basal SM tone of the urinary bladder and serves as a common final pathway of various contractile stimuli in rabbits, rats, mice, and pigs as well as humans. In addition, this pathway is upregulated in response to a number of pathological conditions associated with bladder SM dysfunction. Similarly, RhoA/Rho-kinase signaling is essential for normal ureteral function and development and is upregulated in response to ureteral outlet obstruction. In addition to its critical role in bladder SM function, a role of ROK in the urothelium is also beginning to emerge as well as roles for ROK in bladder infection and invasion and metastasis of bladder cancer.

Lower urinary tract symptoms, prostate volume, uroflowmetry, residual urine volume and bladder wall thickness in Turkish men: a comparative analysis

AIM

To evaluate the association between lower urinary tract symptoms (LUTS) severity and bladder wall thickness (BWT).

MATERIALS AND METHODS

The study included 155 patients referred to outpatient clinics for LUTS. Patients were divided into three groups due to their IPSS. Group A included the patients with mild symptoms, group B included patients with moderate symptoms and group C included patients with severe symptoms. The patients were again divided into two groups due to their uroflowmetry results. Group 1 included the patients whose Q (max) </= 10 ml/s and group 2 included the patients whose Q (max) > 10 ml/s.

RESULTS

The mean BWT was 4.14 + 1.03 mm (from 3 to 9 mm). Although there was no difference between the IPSS groups in BWT (P = 0.325), it was statistically significant between uroflowmetry study groups (P < 0.01).

CONCLUSIONS

BWT seems to be significantly increased in men who have Q (max) values smaller than 10 ml/s.

Stereological study of collagen and elastic system in the detrusor muscle of bladders from controls and patients with infravesical obstruction

OBJECTIVE

Compare detrusor muscle of normal and patients with infravesical obstruction, quantifying the collagen and elastic system fibers.

MATERIALS AND METHODS

We studied samples taken from bladders of 10 patients whose ages ranged from 45 to 75 years (mean = 60 years), who underwent transvesical prostatectomy for treatment of BPH. Control material was composed of 10 vesical specimens, removed during autopsies performed in cadavers of accident victims, with ages between 18 and 35 years (mean = 26 years).

RESULTS

The results of collagen and elastic fibers quantification (volumetric density) demonstrated the following results in percentage (mean +/- standard deviation): collagen in BPH patients = 4.89 +/- 2.64 and 2.32 +/- 1.25 in controls (p < 0.0001), elastin in BPH patients = 10.63% +/- 2.00 and 8.94% +/- 1.19 in controls (p < 0.0001).

CONCLUSION

We found that the components of connective tissue, collagen and elastic system fibers are increased in the detrusor muscle of patients with infravesical obstruction, when compared to controls.

Detrusor Quantitative Morphometry in Obstructed Males and Controls

PURPOSE

We studied the usefulness of computer assisted morphometry for measuring detrusor muscle cell diameter and the connective tissue-to-smooth muscle ratio in patients with bladder outlet obstruction, acute urinary retention and a nonobstructed control group.

MATERIALS AND METHODS

A prospective study was done in patients with bladder outlet obstruction undergoing transurethral prostate resection. Patients were divided into 33 with obstruction and 14 in acute urinary retention. A total of 15 males without obstruction undergoing transurethral prostate resection for bladder tumor formed the control group. Detrusor specimens were obtained during transurethral prostate resection. Detrusor muscle cell diameter was measured using light microscopy and a semiautomatic image analysis system. The connective tissue-to-smooth muscle ratio was automatically determined with computer assisted image analysis. Symptoms and urodynamic assessment were performed preoperatively and 6 months postoperatively.

RESULTS

A total of 62 patients were included. The obstruction and acute urinary retention groups had a statistically higher detrusor muscle cell diameter and more fibrosis than the control group. Patients in acute urinary retention had more intrafascicular fibrosis (higher connective tissue-to-smooth muscle ratio at 40x magnification) than patients with obstruction. There were no differences in detrusor muscle cell diameter or interfascicular fibrosis (connective tissue-to-smooth muscle ratio at 10x magnification) between the obstruction and acute urinary retention groups. Detrusor muscle cell diameter correlated with symptom duration and functional recovery after transurethral prostate resection. Detrusor fibrosis correlated with preoperative detrusor pressure at maximum flow and postoperative compliance. Patients in acute urinary retention had fewer symptoms and higher residual volume. Other urodynamic parameters and their improvement after surgery were similar in the acute urinary retention and obstruction groups.

CONCLUSIONS

Morphometric differences in detrusor muscle cell diameter and the connective tissue-to-smooth muscle ratio were observed between controls and patients with obstruction. There is an increase in detrusor muscle cell diameter and fibrosis in bladder outlet obstruction and more intense intrafascicular collagen deposition in patients in acute urinary retention.

The detrusor muscle: an innocent victim of bladder outlet obstruction

OBJECTIVES

Benign prostatic hyperplasia (BPH) is considered a frequent cause of bladder outlet obstruction (BOO) and lower urinary tract symptoms (LUTS), although the physiopathologic mechanism through which BPH causes LUTS is not clear. Several morphologic and functional modifications of the bladder detrusor have been described in patients with BPH and could play a direct role in determining symptoms. The opinion is spreading that the enlarged prostates in patients with LUTS is nothing more than a mere bystander. Evidence has accumulated, however, supporting the role of BPH-related BOO as the direct cause determining bladder dysfunction and indirectly causing urinary symptoms. The present review addresses the bladder response to BOO, particularly focusing on the physiopathologic cascade that links obstructive BPH to bladder dysfunction.

METHODS

A literature review of peer-reviewed articles has been performed, including both in vivo and in vitro studies on human tissue and animal model experiments.

RESULTS

Epithelial and smooth muscle cells in the bladder wall are mechanosensitive, and in response to mechanical stretch stress caused by BOO, undergo modifications of gene expression and protein synthesis. This process involves several transduction mechanisms and finally alter the ultrastructure and physiology of cell membranes, cytoskeleton, contractile proteins, mitochondria, extracellular matrix, and neuronal networks.

CONCLUSIONS

BOO is the initiator of a physiopathologic cascade leading to deep changing of bladder structure and function. Before being a direct cause of storing-phase urinary symptoms, the bladder is the first innocent victim of prostatic obstruction.

Noninvasive Methods of Diagnosing Bladder Outlet Obstruction in Men. Part 1: Nonurodynamic Approach

PURPOSE

Many methods have been suggested for diagnosing bladder outlet obstruction, as defined by the gold standard of pressure flow studies. Difficulty arises when comparing completely different methods of diagnosing bladder outlet obstruction. A comprehensive review of the literature of the different methods used to diagnose bladder outlet obstruction by noninvasive means was performed with a view to allow such a comparison.

MATERIALS AND METHODS

A MEDLINE search was done of the published literature covering until the end of 2004 on noninvasive methods used to diagnose bladder outlet obstruction. A direct comparison of all different methods was made using the sensitivity and specificity, positive predictive value and likelihood ratio of each test. For many of the techniques these values were calculated from the data presented in the article.

RESULTS

A multitude of methods has been applied to diagnose bladder outlet obstruction. Broadly the methods were divided into nonurodynamic and noninvasive urodynamic methods. Nonurodynamic methods include symptoms, biochemical tests such as prostate specific antigen, ultrasound derived measurements such as post-void residual urine, bladder weight, prostate configuration and size, intravesical prostatic protrusion and the Doppler resistive index. Part 1 of the review explores and discusses the relative merits of the nonurodynamic based methods.

CONCLUSIONS

Ultrasound derived measures such as bladder wall thickness and bladder weight offer a promising possibility of diagnosing bladder outlet obstruction noninvasively. However, further reproducibility and large accuracy studies with better methodological standards are required before they can replace pressure flow studies.

CORRELATION BETWEEN DETRUSOR COLLAGEN CONTENT AND URINARY SYMPTOMS IN PATIENTS WITH PROSTATIC OBSTRUCTION

PURPOSE

We used computerized imaging analysis to compare the collagen content of detrusor specimens between patients affected with symptomatic obstructive benign prostatic hyperplasia (BPH) and asymptomatic controls.

MATERIALS AND METHODS

In our study we enrolled 36 patients with symptomatic urodynamically obstructed BPH undergoing transurethral resection of the prostate. We also enrolled 28 men (mean age 61.3, range 55 to 70) undergoing transurethral resection of the bladder for primitive, singular Ta bladder cancer, with no significant urinary symptoms, as the control group. During the transurethral surgical procedure in controls and in patients with BPH, a biopsy was performed deep through the muscular layer from either of the lateral bladder walls. Computerized morphometric analysis of the stained sections was performed with an image analysis system, and a percentage of collagen fibers was extracted through morphological filtering and expressed as a mean percentage of the total bioptic area.

RESULTS

Collagen content in bladder detrusor specimens was significantly higher in patients with BPH compared to controls (48% and 17% of bioptic area, respectively, p <0.001). Mean detrusor collagen content was clearly higher in patients with severe symptoms than in patients with moderate symptoms (50.45 +/- 8.22% and 43.09% +/- 7.05%, respectively).

CONCLUSIONS

Our study supports the important role of detrusor collagen neo-deposition in determining lower urinary tract symptoms in obstructive BPH. Detrusor collagen content correlates with urodynamic obstruction, the presence and severity of symptoms and, given that collagen neoformation is irreversible could probably have a role in the postoperative persistence of lower urinary tract symptoms in patients undergoing surgery for BPH.

Pathophysiological aspects of bladder dysfunction: a new hypothesis for the prevention of ‘prostatic’ symptoms

This article reviews the literature on the pathophysiology of male lower urinary tract symptoms (LUTS) with the intention of developing a new preventive intervention for this bothersome disease. Traditionally, male voiding dysfunction has been thought to arise from bladder outlet obstruction (BOO) caused by prostatic enlargement. Many years of research, however, have shown that a clear relationship between the size of the prostate and the occurrence or severity of symptoms is doubtful. Because of its crucial role in urination, it is increasingly being accepted that the clinical manifestation of voiding dysfunction relies on the functional behaviour of the bladder. Several animal studies have shown that bladder performance can be improved by increasing urine output. Contrary to alterations observed in pathologic situations, an increased urine output provides a physiologic stimulus for animal bladder function improvement. We hypothesise that a trained bladder should be less susceptible to the harmful effects of ageing and obstruction. Future symptoms may thus be prevented. In humans an increased urine output can be achieved by drinking additional water, which could be an adequate preventive intervention.

Lower urinary tract physiology and pharmacology

This review focuses on what we consider to be the most important findings of the last year relating to the smooth muscle of the lower urogenital system and the different levels of regulation that control its contraction and relaxation. One level is through modulation of the smooth muscle itself or its environment. Recent findings examining myosin isoform composition and collagen content as well as mechanisms that appear to be involved in inducing hyperplasia/hypertrophy of smooth muscle are described. Another method of regulation is via calcium-dependent phosphorylation of the regulatory light chain of myosin, which increases its activity. Interesting results indicating an uncoupling of force from calcium in the bladder are discussed. A third level of regulation is pharmacologic. Thus, the most recent findings related to receptor subtypes, including muscarinic, endothelin, alpha-adrenergic and nicotinic receptors, are presented. In addition, the effects of diabetes, incontinence, and partial bladder outlet obstruction on these modes of contractile regulation are also discussed.