Abbreviations

and Acronyms

AI ¼ arterial balloon endothelialinjury

AOD ¼ arterial occlusive disease

ATP ¼ adenosine triphosphate

Bcap ¼ bladder capacity

Bcomp ¼ bladder compliance

BP ¼ basal pressure

CBI ¼ chronic bladder ischemia

DU ¼ detrusor underactivity

EFS ¼ electrical field stimulation

HCD ¼ high cholesterol diet

IDC ¼ impaired detrusorcontractility

L-NAME ¼ NG-nitro-L-argininemethyl ester

MI ¼ micturition interval

MP ¼ maximum pressure

OAB ¼ overactive bladder

PBOO ¼ partial bladder outletobstruction

PVR ¼ post-void residual urinevolume

TP ¼ threshold pressure

VED ¼ vascular endothelialdysfunction

VV ¼ voided volume

1462 j www.jurology.com

00

T

©

Progressive Vascular Damage May Lead to BladderUnderactivity in Rats

Masanori Nomiya,* Osamu Yamaguchi, Hidenori Akaihata, Junya Hata,

Norifumi Sawada, Yoshiyuki Kojima and Karl-Erik Andersson

From the Division of Bioengineering and Lower Urinary Tract Dysfunction Research (OY), Nihon University School of Engineering,

Koriyama City and Department of Urology, Fukushima Medical University of School of Medicine (HA, JH, YK), Fukushima City,

Japan (MN), and Wake Forest Institute for Regenerative Medicine, Wake Forest University School of Medicine (NS, KEA),

Winston-Salem, North Carolina

Purpose: We assessed whether progressive vascular damage causes bladderunderactivity in rats.

Materials and Methods: Adult male Sprague Dawley� rats were divided into 4groups. Controls received a regular diet and tap water. The L-NAME groupreceived a 2% cholesterol diet and L-NAME (3mg/ml) dissolved in drinking water.The arterial injury group underwent balloon endothelial injury of the commoniliac arteries and received a 2% cholesterol diet and tap water after injury. Thearterial injury/L-NAME group also received L-NAME dissolved in drinkingwater. At 8 weeks urodynamics were performed, bladder tissue was harvested forpharmacological studies, and the iliac arteries and bladders were histologicallyexamined.

Results: Iliac arteries from the injury and injury/L-NAME groups showedneointimal formation and luminal occlusion but arteries from the L-NAME groupdidnot. In theL-NAMEand injurygroupsbladder capacity and voided volumewereless than in controls. Conversely, in the injury/L-NAME group these cystometricparameters were significantly greater than in the other groups. Post-void residualvolume in the injury/L-NAME group tended to increase compared with the othergroups. Contractile responses of bladder strips to various stimuli in the L-NAME,injury and injury/L-NAME groups were significantly less than in controls andthe lowest in the injury/L-NAME group. The injury and injury/L-NAME groupsshowed a significantly increased percent of collagen compared to controls.

Conclusions: Pelvic arterial occlusive disease plus vascular endothelialdysfunction may cause progressive vascular damage resulting in bladderdysfunction that develops from bladder hyperactivity to bladder underactivity.

Key Words: urinary bladder, lower urinary tract symptoms,

arterial occlusive diseases, ischemia, pelvis

EPIDEMIOLOGICAL studies show thatlower urinary tract symptoms, in-cluding OAB syndrome, occur com-monly in men and women with an

Accepted for publication October 21, 2013.Study received Fukushima Medical University animal ethics committee* Correspondence: Division of Bioengineering and Lower Urinary Trac

Nakagawara-1 Tamuramachi, KoriyamaCity, 963-8642, Japan (telephone:þ81-2

22-5347/14/1915-1462/0

HE JOURNAL OF UROLOGY®

2014 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION AND RESEARC

aging related increase in each gen-der.1e4 VED also occurs during thehuman aging process and is an inde-pendent risk factor for atherosclerosis

approval.t Dysfunction Research, Nihon University School of Engineering,4-956-8926; FAX:þ81-24-956-8948; e-mail: mnomiya44@gmail.com).

H, INC.

http://dx.doi.org/10.1016/j.juro.2013.10.097

Vol. 191, 1462-1469, May 2014

Printed in U.S.A.

PROGRESSIVE VASCULAR DAMAGE MAY LEAD TO BLADDER UNDERACTIVITY IN RATS 1463

and hypertension.5 Pelvic arterial insufficiency,a common clinical problem in the elderly popula-tion, may lead to impaired lower urinary tractperfusion and have an important role in OABdysfunction, such as detrusor overactivity and OABsyndrome.1,4,6e8 However, to our knowledge itremains to be established whether chronic ischemiarelated bladder dysfunction may progress to bladderunderactivity.

Clinically, DU is a urodynamic diagnosis basedon pressure flow analysis and defined as a contrac-tion of decreased strength and/or duration thatresults in prolonged bladder emptying and/or fail-ure to achieve complete bladder emptying withina reasonable time.9 It is well known that DU hasan age associated prevalence.10 IDC is consideredan important etiology but to our knowledge anage related decrease in detrusor contractility asthe primary contributor to impaired bladderemptying has not been conclusively demonstrated.11

Other factors may be involved. Contributions ofmotor, sensory and biomechanical dysfunction toimpaired voiding performance independent ofoutlet obstruction were suggested but have beenstudied incompletely. Underactive detrusor is afrustrating diagnosis for clinicians as well aspatients since no effective pharmacological treat-ment is available.11,12

Studies in a rabbit model of CBI suggested thatmoderate ischemia causes bladder hyperactivitywhile severe ischemia causes bladder under-activity.13,14 However, since these groups evaluatedisovolumetric bladder contraction in anesthetizedrabbits, the urodynamic characteristics of CBI werenot described. Thus, appropriate animal models inwhich to study ischemia related bladder underac-tivity seem to be lacking and the aim of the currentstudy was to develop such a model. To achieve ourgoal we investigated whether arterial endothelialinjury of the common iliac arteries together withchronic blockade of endothelial nitric oxide andHCD would cause bladder underactivity in rats.

MATERIALS AND METHODSThe experimental protocol, which complied with setguidelines for animal experiments, was reviewed andapproved by the Fukushima Medical University animalethics committee.

Experimental DesignAdult 16-week old male Sprague Dawley rats weighing450 to 500 gm were divided into control, L-NAME (a nitricoxide synthase inhibitor) (Bachem, Torrance, California),AI and AI/L-NAME groups. Each group was treated for8 weeks. The 9 controls received a regular diet and tapwater. The 10 rats in the L-NAME group received a2% cholesterol diet and L-NAME (3 mg/ml) dissolved in

drinking water. The 9 rats in the AI group underwentballoon endothelial injury of the common iliac arteries andreceived a 2% cholesterol diet and tap water. The 11 ratsin the AI/L-NAME group also received L-NAME (3 mg/ml)dissolved in drinking water. After cystometrogramrecording rats in each group were sacrificed. Bladders andthe vessels from aorta to femoral artery were harvestedfor pharmacological and histological examination.

Arterial Balloon Endothelial InjuryThe procedure for producing AI was described previ-ously.15 Briefly, rats were anesthetized with 2% iso-flurane. A 2Fr Fogarty arterial embolectomy catheter waspassed through the femoral artery into the common iliacartery. The balloon was inflated with air and subse-quently withdrawn from the common iliac artery to thefemoral artery. The maneuver was repeated 10 times oneach side.

Bladder Catheter ImplantationA bladder catheter was implanted as described previ-ously.16,17 Briefly, the bladder dome was delivered outsidethe body and a small incision was made. A polyethylene-50 BD Intramedic� polyethylene catheter with a cuffwas inserted and anchored with a 5-zero silk purse-stringsuture. The proximal catheter was tunneled subcutane-ously to exit at the nape of the neck.

Cystometric Analysis in Conscious RatsAll cystometric studies were performed 3 days aftercatheter implantation in conscious, freely moving rats, asdescribed previously.16,17 Briefly, the catheter was con-nected to a pressure transducer and an infusion pump.Room temperature saline was infused at 10 ml per hour.The pressure transducer was connected to an AP-601Gtransducer amplifier (Nihon Kohden, Tokyo, Japan)and subsequently connected to a MatLab� 4/20 dataacquisition board. An electric balance with a urinecollection system was placed under the metabolic cage andconnected to the MatLab 4/20 data acquisition board.At least 30 minutes were allowed for the rat voidingpattern to stabilize. Reproducible micturition cycles werethen recorded for 60 to 90 minutes. The cystometric pa-rameters investigated were MI, Bcap, VV, PVR (definedas Bcap e VV), BP, TP, MP and Bcomp (defined as Bcap/[TP e BP]).

Organ Bath StudyThe bladder was cut into 2 or 3 strips with mucosa(2 � 10 mm) along the longitudinal axis. The strips wereattached to tissue holders at 1 end and to force trans-ducers at the other end in an organ bath system con-taining 25 ml Krebs buffer aerated with 95% O2 and 5%CO2 at 37C. Bladder strips were subjected to 1 gm restingtension and allowed to stabilize for at least 60 minutes.

Contractions were recorded as changes in tension frombaseline in response to 80 mM KCl, carbachol, EFS and1 mM ATP. Carbachol concentration-response curveswere generated by adding increasing concentrations ofcarbachol starting at 1 nM up to 1 mM. For EFS the stripswere placed between 2 platinum electrodes in the organbath chamber. An electrical pulse (0.5 millisecond atsupramaximum voltage) was delivered for 10 seconds at

1464 PROGRESSIVE VASCULAR DAMAGE MAY LEAD TO BLADDER UNDERACTIVITY IN RATS

increasing frequencies (1, 2, 4, 8, 16 and 32 Hz) using aSEN 3401 stimulator (Nihon Kohden). All responses werenormalized to gm tissue weight. Drugs were obtainedfrom Wako, Tokyo, Japan.

Histological ExaminationThe common iliac arteries and bladders from each groupwere fixed in 10% neutral buffered formalin, embeddedin paraffin and cut into 5 mm sections. Slides were usedfor staining with standard hematoxylin and eosin, andElastica-Masson stains. Common iliac arterial wallthickness was determined by averaging wall thicknessat 4 distinct locations per sample. Computer assistedhistomorphometric analysis of Elastica-Masson stainedbladder tissues was performed using Image-Pro Plus 6.0(MediaCybernetics�) and a microscope (Olympus, CenterValley, Pennsylvania), as described previously.17 Briefly,to determine the percent of collagen content in the musclelayer 4 high power fields were randomly selected perspecimen. The percent of collagen in the muscle layer wascalculated for each high power field as the sum of the bluestained areas divided by the sum of all red and bluestained areas. Care was taken not to include laminapropria or serosa in the analyzed areas. Slides wereexamined by a single investigator.

Statistical AnalysisData were analyzed with SPSS� Statistics 21. All valuesare shown as the mean � SEM. Groups were compared by1-way ANOVA followed by the Bonferroni post hoc testwith p <0.05 considered significant.

RESULTSA total of 26 rats underwent AI, of which 4 (15.3%)died postoperatively due to vascular bleeding intothe retroperitoneum. Of 22 AI rats 13 receivedL-NAME, including 2 excluded from study becauseof leg necrosis. Water consumption was monitoredin rats that received L-NAME. L-NAME andAI/L-NAME rats received a mean of 88.6 � 2.0 and95.6 � 6.5 mg L-NAME daily, respectively.

At 8 weeks body weight in the L-NAME andAI/L-NAME groups was significantly lower than in

Body and bladder weight, and 8-week cystometric parameters in con

Mean � SEM Control Mean � SEM L

No. rats 9 10Body wt (gm) 575.5 � 6.0 492.0 � 9.Bladder wt (gm) 0.24 � 0.01 0.25 � 0.MI (mins) 12.0 � 0.8 7.3 � 1.Bcap (ml) 2.01 � 0.14 1.22 � 0.VV (ml) 1.91 � 0.15 1.17 � 0.PVR (ml) 0.10 � 0.02 0.09 � 0.BP (cm H2O) 15.6 � 0.6 18.1 � 2.TP (cm H2O) 26.3 � 0.9 27.0 � 3.MP (cm H2O) 45.8 � 2.1 45.1 � 4.Bcomp (ml/cm H2O) 0.20 � 0.01 0.15 � 0.

* p <0.01 vs control and AI.† p <0.05 vs control.‡ p <0.01 vs control, L-NAME and AI.§ p <0.05 vs AI.

the control and AI groups (each p <0.01, see table).No motor disturbance or peritonitis was observed inany group.18,19 Although we did not evaluate bloodpressure and organs other than the bladder, severesystemic hypertension and impaired microcircula-tion in various organs could be expected, which mayexplain at least partly the decrease in body weightin rats that received L-NAME. Bladder weight didnot significantly differ among the 4 groups (seetable). All rats that received a 2% cholesterol dietshowed a markedly enlarged fatty liver at necropsy.

Cystometric Analysis

In the L-NAME and AI groups MI was shorter, andBcap and VV were less than in controls. Comparedto controls significant differences were observed inVV in the L-NAME group, and in MI, Bcap and VVin the AI group (each p <0.05). However, differencesin MI and Bcap between the control and L-NAMEgroups failed to attain statistical significance(p ¼ 0.08).

In the AI/L-NAME group MI was significantlylonger, and Bcap and VV were significantly greaterthan in the other 3 groups (p <0.01). PVR tended toincrease compared with the other 3 groups andthere was a significant difference compared with theAI group (vs AI and L-NAME p <0.05 and 0.08,respectively).

BP, TP, MP and Bcomp did not significantly differamong the 4 groups. No significant nonvoiding con-tractions were noted in any group (see table, andfigs. 1 and 2).

Organ Bath Study

To assess changes in the overall contractile responseall bladder strips were initially exposed to KCl. Themean contractile response to KCl in the L-NAME, AIand AI/L-NAME groups was significantly lower thanin controls (p <0.01). The AI/L-NAME group had asignificantly lower mean contractile response thanthe L-NAME group (p <0.05). Contractile responses

trol, L-NAME, AI and AI/L-NAME groups

-NAME Mean � SEM AI Mean � SEM AI/L-NAME

9 114* 550.0 � 11.6 469.0 � 14.6*01 0.26 � 0.02 0.28 � 0.020 6.5 � 0.4† 19.1 � 1.8‡17 1.09 � 0.08† 3.18 � 0.30‡16† 1.06 � 0.08† 2.84 � 0.23‡03 0.05 � 0.01 0.34 � 0.12§4 15.5 � 0.6 13.3 � 1.31 24.2 � 1.2 28.3 � 1.21 42.2 � 2.8 47.6 � 3.602 0.13 � 0.01 0.21 � 0.02

Figure 1. Typical control, L-NAME, AI and AI/L-NAME group

cystometrogram recordings. Horizontal bars indicate 5 minutes.

PROGRESSIVE VASCULAR DAMAGE MAY LEAD TO BLADDER UNDERACTIVITY IN RATS 1465

induced by EFS in L-NAME, AI and AI/L-NAMEbladder strips were significantly less than in con-trol bladder strips at all frequencies (p <0.05vs <0.01). The carbachol concentration-responsecurve showed that the response to carbachol in theL-NAME, AI and AI/L-NAME groups at concentra-tions of 1 mM to 1mMwas significantly lower than incontrols (p <0.05 vs <0.01). The contractile responseto ATP in the L-NAME, AI and AI/L-NAME groups

Figure 2. Study group cystometric parameters. Single asteris

was significantly lower than in controls (p <0.01,fig. 3).

Histological Examination

Common iliac arterial wall thickness. Hematoxylin andeosin staining of iliac artery cross-sections from theAI and AI/L-NAME groups demonstrated obviousarterial wall thickening with neointimal formationcompared with the control and L-NAME groups.Average iliac artery wall thickness in the AI andAI/L-NAME groups was significantly greater thanin the control and L-NAME groups. Furthermore,arterial wall thickness in the AI/L-NAME groupsignificantly differed from that in the AI group (fig. 4).

Histomorphometric analysis. Bladder tissue Elastica-Masson staining revealed an increased percentof collagen in the muscle layer in the AI and AI/L-NAME groups compared with controls. The AIgroup (p <0.01 and <0.05) and the AI/L-NAMEgroup (p <0.05 and 0.06) differed significantly fromthe control and L-NAME groups, respectively (fig. 5).

DISCUSSIONIt is well known that chronic ischemia induced byvascular disease13e15,17,20e22 and aging23 can lead tofunctional and structural changes in the bladder.We previously evaluated contractility in the chron-ically ischemic rat bladder in vitro and noted that

k indicates p <0.05. Double asterisks indicate p <0.01.

Figure 3. Contractile response to 80 mM KCl, frequency response to electrical field stimulation (EFS), concentration-response curve to

carbachol (Cch) and contractile response to 1 mM ATP in 9 control (22 strips), 10 L-NAME (28 strips), 9 AI (19 strips) and 11 AI/L-NAME

(22 strips) rats. Single asterisk indicates p <0.05. Double asterisks indicate p <0.01. Single dagger indicates control vs L-NAME p <0.05

and vs AI/L-NAME p <0.01. Double daggers indicate control vs L-NAME and AI p <0.05, and vs AI/L-NAME p <0.01. Triple daggers

indicate control vs L-NAME, AI and AI/L-NAME p <0.01.

1466 PROGRESSIVE VASCULAR DAMAGE MAY LEAD TO BLADDER UNDERACTIVITY IN RATS

contractile responses to membrane depolarization,EFS, and cholinergic and purinergic stimulationdecreased significantly compared to controls.17,21

This was confirmed in the current study, in whichwe also observed that chronic L-NAME exposurehad similar effects. This suggests that decreasedmuscle strip contractility due to chronic L-NAMEexposure may be attributable to CBI associated withVED and severe systemic hypertension.

Chronic L-NAME treatment can promote persis-tent hypertension and renal damage in rats.19,24

Using a high dose of L-NAME (0.6 mg/ml dissolvedin drinking water) for 4 to 6 weeks Ribeiro et alobserved a severe, progressive form of hypertensionassociated with glomerular ischemia, glomerulo-sclerosis and renal interstitial expansion.25 Son et alevaluated bladder function in a rat model of VEDand noted that L-NAME (3 mg/ml dissolved indrinking water) for 2 weeks together with a 1%cholesterol diet for 8 weeks to induce vascularintimal changes caused bladder dysfunction.26

Our aim was to investigate whether severevascular damage and ischemia could inducebladder underactivity. We also assessed whetherthe severity of bladder dysfunction, ranging from

bladder hyperactivity to bladder underactivity,depends on the degree of vascular damage andischemia. To produce more severe vascular damagethe duration of L-NAME exposure was longer andthe cholesterol content in the diet was higher thanin other series. Since the most pronounced func-tional and morphological changes were found bycombining AI and L-NAME exposure, it is reason-able to assume that bladder microcirculation maybe more decreased by AOD plus VED than by AODalone or VED alone.

This suggestion is supported by the study of Linet al, which showed that 7-day L-NAME pretreat-ment in rabbits was more detrimental to bladderfunction after chronic PBOO than PBOO alone.27

The group evaluated blood vessel density in thebladder wall and observed that vascular density inthe L-NAME pretreated PBOO group was signifi-cantly less than in the PBOO alone group. Lin et alsuggested that the negative effects of L-NAME onblood flow were significantly more important thanthe positive effects of L-NAME on reactive nitrogenspecies generation. They also thought that inhibit-ing blood flow by L-NAME enhanced the bladderdysfunction mediated by PBOO. Thus, the current

Figure 4. A and B, common iliac artery cross-sections in control, L-NAME, AI and AI/L-NAME groups. A, H&E, reduced from �40. Scale

bars indicate 2.0 mm. B, H&E, reduced from �400. Scale bars indicate 200 mm. C, average wall thickness of common iliac arteries in 9

control (18 vessels), 10 L-NAME (20 vessels), 9 AI (18 vessels) and 11 AI/L-NAME (22 vessels) rats. Asterisks indicate p <0.01.

PROGRESSIVE VASCULAR DAMAGE MAY LEAD TO BLADDER UNDERACTIVITY IN RATS 1467

findings suggest that IDC severity was associatedwith the degree of vascular damage and imply thatchronic ischemia/vascular dysfunction can causesevere IDC.

Collagen deposition in the muscle layer waspronounced in the AI and AI/L-NAME groups.Although we expected more severe fibrosis in AI/L-NAME bladders, the collagen ratio was similarto that in AI bladders. Chronic L-NAME treatmentwith HCD tended to increase the collagen ratio butthis finding failed to attain statistical significance.However, it cannot be excluded that more severebladder fibrosis would have developed with a longerduration of endothelial nitric oxide synthase inhi-bition together with HCD. To our knowledgethe mechanism(s) behind the collagen depositionremains to be established. However, Azadzoi et alsuggested that fibrosis caused by severe bladderischemia may be related to increased transforminggrowth factor-b1 expression.28

We also confirmed previous observations thatcystometry after chronic L-NAME treatment mayreveal increased bladder activity and AI can causebladder hyperactivity, defined as shortened MI,decreased Bcap and VV, without affecting MPor PVR in conscious, freely moving rats.15,17,22,26

Monica et al suggested that the lack of nitricoxide caused by chronic L-NAME treatment mayinduce bladder hyperactivity associated withimpaired bladder outlet relaxation during voiding.29

However, in the current study increased MP oncystometry and increased bladder weight, suggest-ing impaired bladder outlet relaxation, were notobserved. Our cystometric findings were similarto those reported by Son et al.26 Thus, chronicL-NAME treatment with HCD may lead toincreased bladder activity associated with VED andhypertension related CBI.

Increased bladder activity under ischemic/hypoxic conditions might be a defensive mechanismbecause under these conditions continued urinestorage and distension induce vessel compression.In turn, this may worsen ischemia/hypoxia byconsuming more energy during the voiding phase.Thus, these findings suggest that the model that weused may reflect a state of CBI, in which compen-satory mechanisms still enabled relatively normalvoiding despite IDC. Conversely, over distensioninduced by prolonged MI and increased Bcap wereobserved in the AI/L-NAME group. This impliesthat lack of perfusion, repeat ischemia/reperfusionduring the micturition cycle and accumulation of

Figure 5. Control, L-NAME, AI and AI/L-NAME bladder tissue. A, Elastica-Masson stain, reduced from �400. Scale bars indicate 200 mm.

B, collagen findings in 8 or 9 preparations. Single asterisk indicates p <0.05. Double asterisks indicate p <0.01.

1468 PROGRESSIVE VASCULAR DAMAGE MAY LEAD TO BLADDER UNDERACTIVITY IN RATS

noxious oxidative elements in the bladder mighteventually lead to the failure of these defensivemechanisms.22,30

It is well known that nerves are highly sensitive toischemia, hypoxia and oxidative stress. In fact, inour previous study the number of nerve fibers posi-tive for the nonspecific nerve marker protein geneproduct 9.5 significantly decreased in AI bladderscompared to controls.21 It seems reasonable toassume that chronic ischemia influences not onlyefferent but also afferent nerves. Therefore, whenbladder ischemia becomes severe, afferent sensoryinput from the bladder might be decreased and Bcapmay increase. Under ischemic/hypoxic conditionsover distension can lead to further impairment ofbladder microcirculation and tissue damage. There-fore, it is conceivable that IDC, as reflected by ourin vitro studies, and over distension may cause PVR.

Although a decrease in MP was not observed inthe AI/L-NAME group, prolonged MI and increasedBcap may have resulted from decreased afferentsensory input from the bladder, which was pre-sumably caused by severe bladder ischemia. Sincevascular damage and subsequent bladder ischemiaare responsible for detrusor overactivity progressiveto DU, the AI/L-NAME group seemed to showthe initial stage of DU characterized by reducedafferent activity. For example, as seen on urody-namics in patients with early stage diabetesmellitus, bladder sensation is decreased, which may

result in a significant increase in Bcap comparedwith that in normal subjects. Since detrusorcontractility is considered to be maintained in thisearly stage of diabetes mellitus, these patients canvoid a large amount of urine stored during filling.However, because of over distension due toincreased bladder capacity, PVR significantly in-creases. Thus, the AI/L-NAME group may reflectthe start of bladder underactivity.

There are several limitations of the currentseries. For practical reasons actual bladder bloodflow was not measured. We did not evaluate bladderafferent nerve function or changes in the propertiesof the urothelium/lamina propria induced by CBI,which may also influence the initiation of void-ing reflex.

The translational value of a rat model can alwaysbe questioned. Nevertheless, we believe that someof the consequences of chronic pelvic ischemia/vascular dysfunction for bladder function andmorphology in our model may also be valid inhumans. In addition, we think that our model canbe of value for further studies of the pathophysi-ology of bladder underactivity and for the evalua-tion of possible therapeutic interventions.

CONCLUSIONSChronic pelvic AOD plus VED produced severevascular damage and ischemia, leading to increased

PROGRESSIVE VASCULAR DAMAGE MAY LEAD TO BLADDER UNDERACTIVITY IN RATS 1469

Bcap, and to PVR, IDC in vitro and bladder fibrosis.These findings suggest that in rats progressivevascular damage causes bladder dysfunction, which

develops from bladder hyperactivity to bladderunderactivity. To our knowledge it remains to beestablished whether this may occur also in humans.

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