A prospective evaluation of detrusor ultrastructural changes in bladder outlet obstruction

Systematic review of urinary biomarkers of female bladder outlet obstruction (fBOO)

Objective: Diagnosis of bladder outlet obstruction (BOO) in females is often challenging, not only because of the overlap in storage and voiding symptoms in women with various etiologies of lower urinary tract (LUT) dysfunction but also due to the lack of standardized urodynamic criteria to define the condition. There is an unmet need of biologic markers to evaluate BOO in females as an adjunct to other clinical criteria. We sought to elucidate the role of urinary biomarkers in female BOO. Material and methods: We performed a systematic review of studies involving urinary biomarkers in female BOO. The search was performed in PubMed. A total of 58 papers were retrieved and 2 were included for final analysis.Results: Currently, there are no validated biologic markers for female BOO available. Having a biomarker that can be obtained through a urine sample will be an invaluable tool to evaluate and counsel patients with LUT symptoms and possible BOO. The use of NGF as an indicator of BOO in female patients seems to be promising: NGF levels are elevated in women with BOO when compared with normal controls. Conclusions: We found that NGF levels may be applied as a useful biomarker in the diagnosis and evaluation of female patients with BOO symptoms. It will not completely replace other clinical diagnostic tools such as formal urodynamic testing but play a role as a supplement to it. Nevertheless, further studies should be conducted to establish NGF levels as a female BOO biomarker and a routine testing modality.

Men with Chronic Urinary Retention: Treatments, Complications, and Consequences

OBJECTIVES

To explore the treatment options for chronic urinary retention (CUR) in men, including treatment-related complications and consequences.

METHODS

This retrospective cohort study included male patients diagnosed with a non-neurogenic, symptomatic and/or high-risk, CUR >150 mL in a large Dutch non-academic teaching hospital. Data for treatments, complications, and consequences (e.g., diagnostics, additional treatments, and hospital contact) were recorded and incidence rate ratios (IRRs) were calculated.

RESULTS

We enrolled 177 patients (median age, 77 years; range, 44-94) with a median follow-up of 68 months (range, 1-319) during which they had a median of 8 events (range, 1-51). Most patients initially received a urethral catheter (74%) and some form of catheterization as their final treatment (87%). Compared with non-surgical cases, catheterization was more likely to be stopped after de-obstructive prostate surgery (IRR, 4.18; p < 0.001). Urinary tract infection (IRR, 3.68; p < 0.001) and macroscopic hematuria (IRR, 5.35; p < 0.001) were more common with catheterization, but post-renal problems were more likely in patients with no catheterization (IRR, 25.36; p < 0.001). The lowest chance of complication was with clean intermittent catheterization, and complications were usually managed in outpatient (77%) or emergency (6%) departments, rather than by admission (17%).

CONCLUSIONS

Most patients require catheterization for CUR, with clean intermittent catheterization preferred due to its comparatively lower complication risk. De-obstructive prostate surgery increases the chance of stopping catheterization and may be considered in suitable cases.

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.

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.

New frontiers in molecular and imaging research on evaluation and diagnosis of bladder outlet obstruction in women

Purpose

Diagnosis of bladder outlet obstruction (BOO) often presents a challenge in female patients. Traditional diagnostic elements such as symptom history and urodynamic data are rarely clear cut in women. Therefore, we sought to review the current literature on diagnosis of female BOO, focusing on new frontiers in the realm of molecular markers and imaging modalities.

Recent Findings

In addition to fluoroscopy in the setting of videourodynamics, ultrasound and MRI can augment the diagnosis and aid in therapeutic planning in certain etiologies of female BOO. Furthermore, multiple potential biomarkers (i.e. nerve growth factor, prostaglandins, ATP) that have been studied in correlation to BOO in animal models as well as human subjects hold promise for diagnostic applications.

Summary

These novel techniques may augment standard clinical and urodynamic evaluation of BOO in females. Future directions include further studies of each of these biomarkers in female patients with BOO compared to normal controls to test their feasibility as potential screening tools.

Electron microscopic changes of detrusor in benign enlargement of prostate and its clinical correlation

AIMS

To study the ultra structural changes in bladder musculature in cases of BPE and their clinical relevance.

MATERIAL AND METHODS

In this descriptive longitudinal, controlled, observational study patients were enrolled into three groups, group 1, group 2A and group 2B. Control group (group-1) consisted of age matched normal male patients, who underwent surveillance or diagnostic cystoscopy for microscopic hematuria or irritative symptoms. Case group (group-2) comprised of patients with BPE, undergoing TURP. Case group (group-2) was further classified into: Category 2A (patients not on catheter) and cat-egory 2B (patients on catheter). All relevant clinical parameters like IPSS, prostate size, Qmax, PVR were recorded. Cystoscopy and bladder biopsy were performed in all patients. Various ultrastructural parameters like myocytes, fascicular pattern, interstitial tissue, nerve hypertrophy and cell junction pattern were analyzed under electron microscope and they were clinically correlated using appropriate statistical tests.

RESULTS

Control group had significant difference as compared to case group in terms of baseline parameters like IPSS, flow rate and prostate size, both preoperatively and postoperatively, except for PVR, which was seen only preoperatively. There was statistically significant difference in ultrastructural patterns between case and control group in all five electron microscopic patterns. However, no significant difference was found between the subcategories of case groups.

CONCLUSIONS

BPE is responsible for ultra structural changes in detrusor muscle and these changes remain persistent even after TURP. Nerve hypertrophy, which was not thoroughly discussed in previous studies, is also one of the salient feature of this study.

Characterization of miRNA-regulated networks, hubs of signaling, and biomarkers in obstruction-induced bladder dysfunction

Bladder outlet obstruction (BOO) induces significant organ remodeling, leading to lower urinary tract symptoms accompanied by urodynamic changes in bladder function. Here, we report mRNA and miRNA transcriptome sequencing of bladder samples from human patients with different urodynamically defined states of BOO. Patients' miRNA and mRNA expression profiles correlated with urodynamic findings. Validation of RNA sequencing results in an independent patient cohort identified combinations of 3 mRNAs (NRXN3, BMP7, UPK1A) and 3 miRNAs (miR-103a-3p, miR-10a-5p, miR-199a-3p) sufficient to discriminate between bladder functional states. All BOO patients shared cytokine and immune response pathways, TGF-β and NO signaling pathways, and hypertrophic PI3K/AKT signaling pathways. AP-1 and NFkB were dominant transcription factors, and TNF-α was the top upstream regulator. Integrated miRNA-mRNA expression analysis identified pathways and molecules targeted by differentially expressed miRNAs. Molecular changes in BOO suggest an increasing involvement of miRNAs in the control of bladder function from the overactive to underactive/acontractile states.

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.

Eight-Year Experience With Botulinum Toxin Type-A Injections for the Treatment of Nonneurogenic Overactive Bladder: Are Repeated Injections Worthwhile?

Purpose:

To investigate the efficacy and safety of repeated botulinum toxin type-A (BTX-A) injections for patients with drug-refractory nonneurogenic overactive bladder (NNOAB) and explore factors predictive of outcome.

Methods:

Data were collected from all patients receiving repeated BTX-A injections for drug-refractory NNOAB between 2004 and 2012. Trigone-sparing injections were administered under sedation with antibiotic prophylaxis. Patient characteristics including age, sex, preoperative urodynamics, injection number, BTX-A dose, complications, and patient global impression of improvement (PGI-I) scores were collected. Correlations between patient factors and outcomes were assessed by using Pearson’s chi-square tests.

Results:

Fifty-two patients with a mean age of 67.4 years (range, 26–93 years) received 140 BTX-A injections in total; 33 (64%), 15 (29%), and 4 patients (7%) received 2, 3 to 4, and 5 to 8 injections, respectively. Mean follow-up time was 49 months (range, 9–101 months). Nine patients developed urinary tract infection; additionally, 3 patients experienced transient urinary retention. Median PGI-I score was 2 out of 7 (interquartile range [IQR], 2). For 46 patients, the PGI-I score remained stable with the administration of each injection. Pearson chi-square tests revealed that male patients or reduced bladder compliance was associated with a higher (worse) PGI-I score. Median PGI-I scores for men and women were 3 (IQR, 1) and 2 (IQR, 1), respectively; additionally, median PGI-I scores for those with normal bladder compliance and those with reduced bladder compliance were 2 (IQR, 2) and 4.5 (IQR, 1), respectively. Median PGI-I scores and complication rates were the same in the older patient (≥70 years) and younger (<70 years) patient cohorts.

Conclusions:

Efficacy is maintained with repeated BTX-A injections. Patients including the elderly show a good degree of tolerability with a low complication rate. Male patients or reduced bladder compliance is associated with poorer outcomes.

Pathophysiology and animal modeling of underactive bladder

While the symptomology of underactive bladder (UAB) may imply a primary dysfunction of the detrusor muscle, insights into pathophysiology indicate that both myogenic and neurogenic mechanisms need to be considered. Due to lack of proper animal models, the current understanding of the UAB pathophysiology is limited, and much of what is known about the clinical etiology of the condition has been derived from epidemiological data. We hereby review current state of the art in the understanding of the pathophysiology of and animal models used to study the UAB.

Detrusor Underactivity: The Current Concept of the Pathophysiology

Based on evidence from available literature, we review the pathophysiology of detrusor underactivity (DU). DU is likely to be multifactorial. Aging reduces detrusor activity, but other concomitant causes may aggravate this condition, resulting in decrease of detrusor contractility. Impaired detrusor contractility has been regarded as a major etiologic factor of DU. However, a more complex pathology has been proposed. As contributing factors to DU, we discuss disturbances of the sensory afferent side of the micturition reflex, the central nervous system (CNS) and the efferent side of the reflex, including nerves and the detrusor muscle. Particularly, dysfunction of afferent nerves in the bladder and urethra may play a crucial role in the pathogenesis of DU. In addition, recent studies suggest that chronic bladder ischemia and resultant oxidative stress cause detrusor overactivity progressing to DU and inability to empty the bladder.

Detrusor underactivity and the underactive bladder: a new clinical entity? A review of current terminology, definitions, epidemiology, aetiology, and diagnosis

CONTEXT

Detrusor underactivity (DU) is a common cause of lower urinary tract symptoms (LUTS) in both men and women, yet is poorly understood and underresearched.

OBJECTIVE

To review the current terminology, definitions, and diagnostic criteria in use, along with the epidemiology and aetiology of DU, as a basis for building a consensus on the standardisation of current concepts.

EVIDENCE ACQUISITION

The Medline and Embase databases were searched for original articles and reviews in the English language pertaining to DU. Search terms included underactive bladder, detrusor underactivity, impaired detrusor contractility, acontractile detrusor, detrusor failure, detrusor areflexia, raised PVR [postvoid residual], and urinary retention. Selected studies were assessed for content relating to DU.

EVIDENCE SYNTHESIS

A wide range of terminology is applied in contemporary usage. The only term defined by the standardisation document of the International Continence Society (ICS) in 2002 was the urodynamic term detrusor underactivity along with detrusor acontractility. The ICS definition provides a framework, considering the urodynamic abnormality of contraction and how this affects voiding; however, this is necessarily limited. DU is present in 9-48% of men and 12-45% of older women undergoing urodynamic evaluation for non-neurogenic LUTS. Multiple aetiologies are implicated, affecting myogenic function and neural control mechanisms, as well as the efferent and afferent innervations. Diagnostic criteria are based on urodynamic approximations relating to bladder contractility such as maximum flow rate and detrusor pressure at maximum flow. Other estimates rely on mathematical formulas to calculate isovolumetric contractility indexes or urodynamic "stop tests." Most methods have major disadvantages or are as yet poorly validated. Contraction strength is only one aspect of bladder voiding function. The others are the speed and persistence of the contraction.

CONCLUSIONS

The term detrusor underactivity and its associated symptoms and signs remain surrounded by ambiguity and confusion with a lack of accepted terminology, definition, and diagnostic methods and criteria. There is a need to reach a consensus on these aspects to allow standardisation of the literature and the development of optimal management approaches.

Transurethral prostate resection in patients with hypocontractile detrusor--what is the predictive value of ultrastructural detrusor changes?

PURPOSE

Men with detrusor failure and chronic urinary retention have a lower voiding success rate and higher postoperative morbidity following transurethral prostatectomy than those with bladder outlet obstruction. Current investigations, including urodynamics, may be unable to predict the response to surgical treatment. We identified ultrastructural features on detrusor biopsy that correlated with the postoperative voiding outcome in patients with a hypocontractile detrusor undergoing transurethral prostatectomy.

MATERIALS AND METHODS

Detrusor biopsies were obtained from 17 patients with urodynamic evidence of bladder outlet obstruction or a hypocontractile detrusor undergoing transurethral prostatectomy and from 5 controls. Specimens were examined by transmission electron microscopy. Ten individual detrusor ultrastructural features were analyzed. Findings were compared with preoperative and postoperative clinical parameters.

RESULTS

Failure to void after transurethral prostatectomy was significantly associated with the ultrastructural features of variation in muscle cell size, muscle cell shape, collagenosis and abnormal fascicles. These 4 features were significantly associated with each other, defining a distinctive pattern of detrusor failure. For transurethral prostatectomy failure the sensitivity, specificity, and positive and negative predictive values of all 4 features together were 60%, 91%, 75% and 84%, respectively. Three or 4 features on detrusor biopsy predicted voiding failure.

CONCLUSIONS

Detrusor ultrastructural analysis is highly predictive of voiding outcome following transurethral prostatectomy in patients with detrusor failure. Patients with ultrastructural features previously described as part of the myohypertrophy pattern do not have a primary diagnosis of bladder outlet obstruction but rather detrusor failure secondary to bladder outlet obstruction.

Adherence junctions and cadherin-11 in normal and overactive human detrusor smooth muscle cells

PURPOSE

We investigated whether analysis of adherence junctions in human detrusor could be used as a diagnostic tool to determine detrusor overactivity.

MATERIALS AND METHODS

We characterized the protein composition of adherence junctions in the human bladder using cadherin-11 since our group previously found that cadherin-11 could be an integral structural protein of adherence junctions. We obtained a total of 46 biopsies from 23 patients categorized into 4 groups, including 5 who were normal, and 6 each with neurogenic disease with detrusor overactivity, bladder outlet obstruction with detrusor overactivity and idiopathic detrusor overactivity. Specimens were processed to study cadherin-11 expression using combined immunohistochemical and immunogold electron microscopy techniques. Cadherin-11 expression was semiquantitatively analyzed and correlated to muscle fascicle structure and collagen in the extracellular spaces.

RESULTS

Immunogold labeling showed highly specific cadherin-11 expression at adherence junctions in detrusor smooth muscle cells. During immunohistochemical staining a wide variety of cadherin-11 expression and fascicle structure was found in the same specimen. No correlation was noted between detrusor overactivity and cadherin-11 expression. However, cadherin-11 seemed to be down-regulated with intercellular space widening and collagenosis.

CONCLUSIONS

Cadherin-11 is an integral structural protein of the adherence junction. Defects in the overactive detrusor are highly punctate. Quantitative analysis of adherence junctions using biopsy cannot replace urodynamic evaluation as a predictor of detrusor overactivity in the human bladder.

[Nocturia and benign prostatic hyperplasia]

BACKGROUND/AIM

Nocturia often occures in patients with benign prostata hyperplasia (BPH). The aim of the study was to investigate the frequency of nocturia in patients with BPH. Nocturia and other factors associated with it were also investigated.

METHODS

Forty patients with the confirmed diagnosis of BPH were studied. Transurethral and transvesical prostatectomy were performed in all the patients. Simptoms were evaluated with the International Prostete Sypmtom Score before, as well as three and six months after the surgery. All the results were compared with the control group.

RESULT

. There was no statistically significant difference between the patients before and after the surgery regarding nocturia. There was, howerer, a statistically significant difference between the operated patients and the control group regarding nocturia, as well as a statistically significant correlation between noctruia and the age of the patients in both the investigated and the control group. A correlation also existed between nocturia and the prostatic size.

CONCLUSION

There was no statistically significant improvement in symptoms of nocturia after the surgery. It is necessary to be very careful in decision making in patients with nonabsolute indiction for surgery and isolated bothersome symptom of nocturia. Age of a patient should also be considered in the evaluation of favourable result of the surgery because of a significant correlation between noctura and the age of a patient.

Basic fibroblast growth factor modulates proliferation and collagen expression in urinary bladder smooth muscle cells

Bladder hypertrophy is a general consequence of bladder outlet obstruction (BOO) and a typical phenomenon observed in clinical urologic diseases such as benign prostatic hyperplasia and neurogenic bladder. It is characterized by smooth muscle hyperplasia, altered extracellular matrix composition, and increased contractile function. Various growth factors are likely involved in hypertrophic pathophysiology, but their functions remain unknown. In this report, the role of basic fibroblast growth factor (bFGF) was investigated using a rat bladder smooth muscle cell (BSMC) culture system and an original animal model, in which bFGF was released from a gelatin hydrogel directly onto rat bladders. bFGF treatment promoted BSMC proliferation both in vitro and in vivo. In vitro, bFGF downregulated the expression of type I collagen, but upregulated type III collagen. ERK1/2, but not p38MAPK, was activated by bFGF, whereas inhibition of ERK1/2 by PD98059 reversed bFGF-induced BSMC proliferation, type I collagen downregulation, and type III collagen upregulation. In the in vivo release model, bFGF upregulated type III collagen and increased the contractile force of treated bladders. In parallel with these findings, hypertrophied rat bladders created by urethral constriction showed increased urothelial bFGF expression, BSMC proliferation, and increased type III collagen expression compared with sham-operated rats. These data suggest that bFGF from the urothelium could act as a paracrine signal that stimulates the proliferation and matrix production of BSMC, thereby contributing to the hypertrophic remodeling of the smooth muscle layer.

Three-dimensional stereology as a tool for evaluating bladder outlet obstruction

OBJECTIVE

In a pilot study we evaluated whether implementation of a novel 3D stereologic technique can prove that bladder outlet obstruction (BOO) is associated with morphologic changes in the bladder wall.

MATERIAL AND METHODS

Ten males (mean age 69.7 years; range 58-84 years) with lower urinary tract symptoms (LUTS) suggestive of BOO and five controls (mean age 48.6 years; range 43-53 years) without LUTS were studied. All participants underwent a full examination, including determination of the International Prostate Symptom Score, laboratory analysis and a urodynamic evaluation. A cold-cup biopsy, taken during cystoscopy, was stereologically evaluated to determine the smooth muscle cell volume and the fractions of collagen and smooth muscle using light and electron microscopy.

RESULTS

The collagen fraction was higher in patients than in controls (probably because the patients were older). There was no relation between the Abrams-Griffiths number and either the interstitial fraction or the collagen fraction. Furthermore, the results suggest an age-associated effect of morphological changes in the bladder wall. The smooth muscle volume also showed no relationship with the severity of obstruction.

CONCLUSIONS

This pilot study shows that, even with the implementation of subtle morphometric techniques, there seems to be no relationship between the severity of BOO and bladder wall morphology. It is possible that interstitial collagen in the bladder wall increases with age. It seems that bladder wall morphology is heterogeneous within small areas.

Detrusor Underactivity: Clinical Features and Pathogenesis of an Underdiagnosed Geriatric Condition

Urinary incontinence and other lower urinary tract symptoms exert a major influence on the health and independence of frail older people. Detrusor underactivity (DU) is defined as a contraction of reduced strength and/or duration, resulting in prolonged bladder emptying and/or a failure to achieve complete bladder emptying within a normal time span. DU may influence the clinical presentation and impede the therapy of disorders as common and as disparate as detrusor overactivity, urinary retention, and benign prostatic hyperplasia. Urodynamically, nearly two-thirds of incontinent nursing home residents exhibit DU. The clinical diagnosis of DU when present alone or in association with other bladder conditions such as detrusor overactivity (detrusor hyperactivity with impaired contractility (DHIC)) is challenging, because symptoms lack adequate precision. A catheterized and increasingly noninvasive ultrasound-based postvoid residual assessment allows a bedside diagnosis of retention and may suggest the presence of DU in individuals (mostly women) with a low likelihood of bladder outlet obstruction (BOO). Nevertheless, it cannot differentiate primary DU from retention secondary to BOO. The management of individuals with DHIC remains unsatisfactory, because antispasmodic anticholinergic medications may worsen retention, whereas bethanechol does not improve bladder emptying. Human detrusor biopsies reveal axonal degeneration, muscle loss, and fibrosis in DU. Animal studies suggest that multiple risk factors, including retention itself, lack of estrogen, infection, inflammation, and aging, may contribute to DU. Priority areas for future research include efforts to facilitate clinical nonurodynamic diagnosis of probable DU plus translational research designed to address the pathogenesis of this complex multifactorial geriatric syndrome.

Null mutation in macrophage migration inhibitory factor prevents muscle cell loss and fibrosis in partial bladder outlet obstruction

Idiopathic detrusor underactivity (DU) and detrusor decompensation which develops following partial bladder outlet obstruction (pBOO) are both associated with smooth muscle degeneration and fibrosis. Macrophage migration inhibitory factor (MIF), an important mediator of bladder inflammation, has been shown to promote fibroblast survival and muscle death in other tissues. We evaluated the hypothesis that MIF has similar actions in the bladder by studying detrusor responses to pBOO or sham surgery in anesthetized female mice rendered null for the mif gene (MIF KO) and in wild-type (WT) controls, all killed 3 wk after surgery. WT mice revealed intense MIF immunoreactivity in urothelial cells which decreased, without change in overall mif mRNA levels. Stereologically sound quantitative morphometric measurements were performed in the middetrusor region of each bladder. MIF KO bladders were normal in appearance, yet were 30–40% heavier, with increased middetrusor collagen and muscle, compared with WT controls. In WT mice, pBOO increased the collagen-to-muscle ratio 1.9-fold and middetrusor collagen 1.8-fold, while nucleated muscle counts were 22% lower. In MIF KO mice, by contrast, pBOO had no significant effect on any of these parameters. In primary bladder muscle cultures, treatment with rMIF protein increased TUNEL staining, raising the proportion of early and late apoptotic cells on flow cytometry. Our studies implicate MIF in the sequence of events leading to detrusor muscle loss and fibrosis in obstruction. They raise the possibility that strategies designed to antagonize MIF synthesis, release, or biological activity could prevent or delay DU and urinary retention.

Increased Expression of Heat Shock Protein 20 and Decreased Contractile Stress in Obstructed Rat Bladder

PURPOSE

Bladder outlet obstruction induces detrusor hypertrophy and it can eventually lead to decreased bladder smooth muscle contractility. Heat shock protein 20 is the proposed mediator of force suppression in vascular smooth muscle. We investigated whether heat shock protein 20 could also mediate the decreased contractility observed in partially obstructed rat bladders.

MATERIALS AND METHODS

Female Wistar rats (Harlan Laboratories, Indianapolis, Indiana) were randomized to partial urethral ligation or sham ligation. After 3 weeks the rats were sacrificed, and the bladders were harvested, frozen, homogenized and analyzed for heat shock protein 20 content by Western blot immunoreactivity. The content of myosin regulatory light chain, a constitutively expressed protein, was determined as a control. Bladder smooth muscle strips were dissected from some rats and mounted for force generation measurement.

RESULTS

At cystectomy obstructed bladders were significantly heavier and had more residual urine compared to sham operated bladders. Heat shock protein 20 immunoreactivity was significantly increased a mean +/- 1 SEM of 1.9 +/- 0.3-fold in obstructed vs sham operated bladders. Control protein myosin regulatory light chain immunoreactivity did not significantly differ in obstructed and sham operated bladders. Maximal stress, that is force per cross-sectional area, was significantly decreased in obstructed vs sham operated bladders. Human bladder was found to express immunoreactive heat shock protein 20.

CONCLUSIONS

We noted that partially obstructed rat bladders 1) express higher levels of heat shock protein 20 and 2) generate less stress than sham operated bladders. These data suggest the possibility that heat shock protein 20 over expression could at least partially mediate the decreased contractile activity observed with partial bladder outlet obstruction. The mechanism for increased heat shock protein 20 expression is unknown but it may involve increased mechanical stress or hypoxia from urethral obstruction. Human bladder expressed immunoreactive heat shock protein 20, suggesting that a similar mechanism could potentially occur in humans. If confirmed in humans, patients with clinical conditions that result in detrusor hypocontractility could potentially benefit from pharmacological interventions aimed at inhibiting heat shock protein 20.

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.

Benign prostate hyperplasia: evaluation of treatment response with DCE MRI

Benign prostate hyperplasia (BPH) is a major disease and its non-surgical therapy a major area of interest. The purpose of this study was to establish perfusion parameters in beagles with BPH using dynamic contrast-enhanced (DCE) MRI and to investigate changes due to the effects of finasteride treatment. Twelve male beagles (mean age 4.4 +/- 0.9,years) were divided into a control and treatment group that received a daily dose of 1 mg/kg finasteride. DCE MRI was carried out in a clinical scanner using a 3D spoiled gradient echo sequence prior to and during treatment. 0.2 mmol/kg contrast agent (gadoteridol) was administered with an injection rate of 0.2 ml/s followed by a 15 ml flush of saline. Contrast enhancement was evaluated by pharmacokinetic mapping of a two-compartment model with colour overlay images in addition to regional ROI analysis. Quantitative parameters were defined by the amplitude of contrast enhancement A, the exchange rate k(ep) and the time to maximum signal enhancement. Dynamic contrast-enhanced MRI investigations of the prostate revealed two distinct zones, an inner, periurethral zone and an outer, parenchymal zone. The periurethral zone is highly vascularized, whereas the parenchymal zone is moderately vascularized when compared to other parenchymal organs. During treatment, in the parenchymal zone the intensity of enhancement (amplitude A) and the time to maximum signal enhancement increased, while the exchange rate k(ep) decreased. Dynamic contrast-enhanced MRI of BPH reveals distinct differences between individual zones within the prostate. Moreover, changes during successful treatment suggest increased blood volume per volume of tissue and decreased vessel leakiness.

Routine bladder biopsies in men with bladder outlet obstruction?

OBJECTIVES

To establish whether routine evaluation of light microscopic changes in bladder biopsies in men with graded bladder outlet obstruction correlates with urodynamic parameters and to evaluate the performance of two pathologists in bladder biopsy interpretation.

METHODS

In 63 consecutive patients presenting with lower urinary tract symptoms suggestive of bladder outlet obstruction, the workup included bladder biopsies, which were semiquantitatively and independently evaluated by two pathologists for fibrosis, elastosis, muscle cell degeneration, inflammation, and additional remarkable findings. Furthermore, as determined by their general impression, the pathologists gave a diagnosis of normal or graded abnormality. The pathologists' performance was compared and the clinical and urodynamic data were correlated to the consensus histologic diagnoses.

RESULTS

Fifty-four of 63 cases could be evaluated. The intraobserver and interobserver reproducibility were reasonable, with a kappa of 0.35 and 0.50, respectively. The consensus diagnosis of abnormal bladder biopsy correlated with impaired bladder compliance and capacity. However, no correlation was found between the presence and severity of histologic abnormalities and Schäfer class, urethral resistance factor, instability, postvoid residual urine volume, symptom score, and prostate volume.

CONCLUSIONS

Although abnormal bladder biopsies correlated significantly with impaired bladder capacity and compliance, routine evaluation of bladder biopsies is not indicated in the evaluation of bladder outlet obstruction.