Therapeutic effect of Low intensity Extracorporeal Shock Wave Therapy (Li-ESWT) on diabetic bladder dysfunction in a rat model

Objectives: Low intensity extracorporeal shock wave therapy (Li-ESWT) has proven to be effective and safe for the treatment of various urological disorders including erectile dysfunction and chronic pelvic pain syndrome. In this study, we elucidated the therapeutic effect and possible mechanisms of Li-ESWT on diabetic bladder dysfunction (DBD) in a rat model.Materials and Methods: In all, thirty-two female Sprague-Dawley rats were divided into three groups: normal control (NC), diabetes mellitus (DM) control, and DM Li-ESWT. The two DM groups were given high fat diets for one month, followed by 2 intraperitoneal injections of streptozotocin (STZ) 30 mg/kg separated by one week. Body weight and fasting blood glucose were monitored every week. Only rats with fasting blood glucose 140 mg/dL or more were considered diabetic and used in the subsequent portions of the study. The Li-ESWTs were applied toward the pelvis of the rats twice a week for 4 weeks with energy flux density (EFD) 0.02 mJ/mm², 500 shocks, at 3Hz. All rats underwent plasma insulin tolerance test, conscious cystometry, leak-point pressure (LPP) assessment, and immunohistochemical studies.Results: DM groups had significantly lower insulin sensitivity and higher body weight. Conscious cystometry also revealed voiding dysfunctions. In the DM Li-ESWT group, the rats had significantly improved voiding functions that were reflected in longer micturition intervals and higher LPP compared to DM control. Immunofluorescence in DM control groups showed increased tyrosine hydroxylase (TH) expression and decreased neuronal nitric oxide synthase (nNOS) expression in the longitudinal urethral smooth muscles. Besides, rats had dilations and deformities of suburothelium capillary network of the bladder, revealing the deterioration of the nerve function of the urethra and destruction of the vascularization of the bladder. However, the DM Li-ESWT group exhibited recovery of the nerve expression of the urethra and vascularization of bladder.Conclusions: Li-ESWT ameliorates the bladder dysfunction and urinary continence in the DBD rat model, reflected in restoration of the nerve expression of the urethra and the vascularization of the bladder. Non-invasive Li-ESWT could be an alternative therapeutic option for DBD.     

Autoantibody-mediated bladder dysfunction in type 1 diabetes

Bladder dysfunction is a common complication of diabetic autonomic neuropathy; however, its cause remains uncertain. We have recently identified a novel IgG autoantibody (Ab) in patients with type 1 diabetes that acts as an agonist at the dihydropyridine (DHP) site of L-type voltage-gated calcium channels (VGCC), disrupting neuronal regulation of visceral smooth muscle. In the present study, passive transfer to mice of IgG from patients with type 1 diabetes was used to investigate the role of anti-VGCC Abs in mediating diabetic bladder dysfunction. Injection of mice with diabetic immunoglobulin (IgG) with anti-VGCC activity induced features of an overactive bladder, including phasic detrusor contractions and a loss of bladder wall compliance. The bladder overactivity is mimicked by the DHP agonist Bay K8644, reversed by the DHP antagonist nicardipine, but is insensitive to the motor nerve blocker tetrodotoxin, indicating that the anti-VGCC Ab acts at the level of the bladder detrusor itself. This study reports the first evidence of Ab-mediated bladder dysfunction in type 1 diabetes, which may be part of a wider spectrum of smooth muscle and cardiac abnormalities.     

Smooth muscle hypertrophy following partial bladder outlet obstruction is associated with overexpression of non-muscle caldesmon

Partial bladder outlet obstruction (PBOO) induces remodeling of urinary bladder smooth muscle (detrusor). We demonstrate an increase in bladder wall mass, muscle bundle size, and a threefold increase in the cross-sectional area of detrusor myocytes following PBOO in male New Zealand White rabbits compared to that of controls. Some bladders with detrusor hypertrophy function close to normal (compensated), whereas others were dysfunctional (decompensated), showing high intravesical pressure, large residual urine volume, and voiding difficulty. We analyzed the expression of smooth muscle-specific caldesmon (h-CaD) and non-muscle (l-CaD) by Western blotting, RT-PCR, and real-time PCR. The expression of l-CaD is increased significantly at the mRNA and protein levels in the decompensated bladders compared to that of normal and compensated bladders. The CaD was also co-localized with myosin containing cytoplasmic fibrils in cells dissociated from obstructed bladders and cultured overnight. Our data show that the inability of decompensated bladders to empty, despite detrusor hypertrophy, is associated with an overexpression of l-CaD. The level of l-CaD overexpression might be a useful marker to estimate the degree of detrusor remodeling and contractile dysfunction in PBOO.     

Adipose Derived Stem Cells and Smooth Muscle Cells: Implications for Regenerative Medicine

The treatment of chronic wounds and other damaged tissues and organs remains a difficult task, in spite of greater adherence to recognised standards of care and a better understanding of pathophysiologic principles. Adipose derived stem cells (ADSCs), with their proliferative and impressive differentiation potential, may be used in the future in autologous cell therapy or grafting to replace damaged tissues. At this point in time, transplanted tissues are often rejected by the body. Autologous grafting would eliminate this problem. ADSCs are able to differentiate into a number of cells in vitro, for example smooth muscle cells (SMCs), when treated with lineage specific factors. SMCs play a key role in physiology and pathology as they form the principle layer of all SMC tissues. Smooth muscle biopsies are often impractical and morbid, and often lead to a low cell harvest. It has also been shown that SMCs derived from a diseased organ can lead to abnormal cells. Therefore, there is a great need for alternative sources of healthy SMCs. The use of ADSCs for cell-based tissue engineering (TE) represents a promising alternative for smooth muscle repair. This review discusses the potential uses of ADSCs and SMCs in regenerative medicine, and the potential of ADSCs to be differentiated into functional SMCs for TE and regenerative cellular therapies to repair diseased organs.     

Telocytes in the urinary system

ABSTRACT: BACKGROUND: Telocytes, a new type of interstitial cells, have been identified in many organs in mammals. The present studies aimed at investigating the ultrastructure, distribution and interactions of telocytes with surrounding cells in the urinary system of rats, to confirm the existence of telocytes in kidneys, ureter and urinary bladder. METHODS: Samples of kidney, ureter, or urinary bladder were harvested for the ultrastructure by the electron microscope. The primary culture of telocytes was performed to investigate the dynamic alterations. RESULTS: Telocytes mainly located in the sub-capsular space of kidney, or between smooth muscle bundles and in the lamina propria of ureter and urinary bladder. Telocytes established numerous contacts with macrophages in the sub-capsular space of kidney, or with smooth muscle cells, nerve endings as well as blood capillaries in the ureter and urinary bladder. The complete morphology of telocytes with telopodes was observed clearly through the primary cell culture from the kidney tissues of rats. CONCLUSIONS: Out data evidenced the existence of telocytes in the urinary system, which may contribute to the tissue reparation and regeneration.     

Bone marrow-derived cells implanted into radiation-injured urinary bladders reconstruct functional bladder tissues in rats

The purpose of this study was to determine whether bone marrow-derived cells implanted into radiation-injured urinary bladders could reconstruct functional bladder tissues. The pelvic region of anesthetized female Sprague-Dawley (SD) rats was irradiated with 2 Gy once a week for 5 weeks. After the last irradiation, the rats were maintained for 2 weeks. Bone marrow cells were harvested from the femurs of donor male green fluorescence protein (GFP)-transfected SD rats and cultured for 7 days. Two weeks after the last radiation exposure, the cultured adherent, proliferating bone marrow-derived cells were implanted into the walls of irradiated urinary bladders. For controls, cell-free solutions were similarly injected. Four weeks after donor cell or control implantations, cystometric, histological, and immunohistochemical investigations were performed. Two weeks after the last irradiation, the smooth muscle layers and nerve fibers of the irradiated urinary bladders were disorganized. The proportions of smooth muscle layer and nerve fiber areas were significantly decreased compared with sham-irradiated urinary bladders. In addition, the remaining smooth muscle cells within the irradiated urinary bladders expressed P4HB, an indicator of collagen synthesis. In the cystometric investigations, the voiding interval of irradiated rats was irregularly prolonged, 7.92±1.09?min, and the residual volume, 0.13±0.03?mL, was significantly higher compared with the sham-irradiated rats (5.50±0.43?mL and 0.05±0.01?mL). After 4 weeks, the smooth muscle layers and nerve fibers in the cell-free control urinary bladders remained similar to the preimplanted irradiated urinary bladders; however, the cell-implanted urinary bladders contained reconstructed smooth muscle layers and nerve fibers, the proportions of each were significantly higher than those in the cell-free injected controls. The expression of P4HB within the cell-implanted urinary bladders decreased. Some GFP-positive implanted cells differentiated into smooth muscle- and nerve-like cells and became organized into the reconstructed tissues. The voiding interval of the cell-implanted rats, 5.46±0.33?min, was regular and similar to that of the sham-irradiated rats, and significantly less than that of the cell-free injected controls, 7.39±0.54?min. The residual volume, 0.04±0.01?mL, was similar to that of the sham-irradiated rats and significantly decreased compared with that of the cell-free injected controls, 0.15±0.05?mL. Therefore, the implantation of bone marrow-derived cells is a potentially useful treatment for radiotherapy-induced urinary dysfunctions.     

Induction of smooth muscle cell-like phenotype in marrow-derived cells among regenerating urinary bladder smooth muscle cells

Tissue regeneration on acellular matrix grafts has great potential for therapeutic organ reconstruction. However, hollow organs such as the bladder require smooth muscle cell regeneration, the mechanisms of which are not well defined. We investigated the mechanisms by which bone marrow cells participate in smooth muscle formation during urinary bladder regeneration, using in vivo and in vitro model systems. In vivo bone marrow cells expressing green fluorescent protein were transplanted into lethally irradiated rats. Eight weeks following transplantation, bladder domes of the rats were replaced with bladder acellular matrix grafts. Two weeks after operation transplanted marrow cells repopulated the graft, as evidenced by detection of fluorescent staining. By 12 weeks they reconstituted the smooth muscle layer, with native smooth muscle cells (SMC) infiltrating the graft. In vitro, the differential effects of distinct growth factor environments created by either bladder urothelial cells or bladder SMC on phenotypic changes of marrow cells were examined. First, supernatants of cultured bladder cells were used as conditioned media for marrow cells. Second, these conditions were reconstituted with exogenous growth factors. In each case, a growth factor milieu characteristic of SMC induced an SMC-like phenotype in marrow cells, whereas that of urothelial cells failed. These findings suggest that marrow cells differentiate into smooth muscle on acellular matrix grafts in response to the environment created by SMC.     

Treatment for chronic ischaemia-induced bladder detrusor dysfunction using bone marrow mesenchymal stem cells: an experimental study

The mechanism of ischaemia-induced bladder dysfunction is not entirely clear, but is thought to be a result of the ischaemia-related M-receptor hypersensitivity to acetylcholine. In addition to nerve injury, ischaemia may cause bladder detrusor fibrosis and urethra de-epithelialization. Bladder dysfunctions caused by bladder outlet obstruction (BOO) and aging detrusor were considered to be associated with chronic ischaemia. To date, there has been no effective treatment for the histological and functional changes of the bladder caused by bladder ischaemia. The present study evaluated the feasibility and effectiveness of using bone marrow mesenchymal stem cells in the treatment of chronic ischaemia-induced bladder detrusor dysfunction in an experimental model. Bone marrow mesenchymal stem cells from Sprague-Dawley (SD) rats were injected into the common iliac artery of experimental animals, then bilateral iliac arteries were ligated and doxazosin mesylate was intragastrically administered. Eight weeks later, urodynamic examination and intravesical pressure measurements were performed on experimental animals. Histological changes of the taken bladder from sacrificed SD rats were evaluated by immunohistochemistry and trichrome staining and the images captured were analyzed by a software program. The average intravesical pressure and detrusor contraction power of the ischaemia group was 16.21±5.26 and 17.26±5.72; those of the experimental group were 24.02±10.06 and 25.84±11.99; the average intravesical pressure and detrusor contraction power of the control group was 28.56±4.48 and 29.57±5.01. The average intravesical pressure and detrusor contraction power of the ischaemia group were significantly lower than those of the experimental and control group, while no significant difference was shown between the experimental and control groups. 5-Bromo-2'-deoxyuridine (BrdU) staining for the experimental group was positive. The percentage of the smooth muscle content in the bladder wall was (25.21±6.28)%, (49.38±6.32)% and (48.00±17.39)% for ischaemia, experimental and control group, respectively. The percentage of smooth muscle in the bladder wall of the ischaemia group was significantly lower than that of the experimental and control group, while no significant difference was observed between the experimental and control groups. The number of nerve fibers per high power field of the experimental group was significantly higher than that of the ischaemia group, but lower than the control group. In conclusion, the percentage of smooth muscle content and the number of nerve cells per high power field decreases in ischaemia bladder, with detrusor contractility decreased. Injection of stem cell suspension into the common iliac artery in rats with ischaemic bladder, followed by intragastric administration of doxazosin mesylate, makes transplanted stem cells regenerate in the bladder tissue, increases the percentage of smooth muscle content and nerve cells per high power field in the bladder wall, and improve bladder detrusor contraction function.     

Nuclear fusion-independent smooth muscle differentiation of human adipose-derived stem cells induced by a smooth muscle environment

Human adipose-derived stem cells hASC have been isolated and were shown to have multilineage differentiation capacity. Although both plasticity and cell fusion have been suggested as mechanisms for cell differentiation in vivo, the effect of the local in vivo environment on the differentiation of adipose-derived stem cells has not been evaluated. We previously reported the in vitro capacity of smooth muscle differentiation of these cells. In this study, we evaluate the effect of an in vivo smooth muscle environment in the differentiation of hASC. We studied this by two experimental designs: (a) in vivo evaluation of smooth muscle differentiation of hASC injected into a smooth muscle environment and (b) in vitro evaluation of smooth muscle differentiation capacity of hASC exposed to bladder smooth muscle cells. Our results indicate a time-dependent differentiation of hASC into mature smooth muscle cells when these cells are injected into the smooth musculature of the urinary bladder. Similar findings were seen when the cells were cocultured in vitro with primary bladder smooth muscle cells. Chromosomal analysis demonstrated that microenvironment cues rather than nuclear fusion are responsible for this differentiation. We conclude that cell plasticity is present in hASCs, and their differentiation is accomplished in the absence of nuclear fusion.     

The spontaneously hypertensive rat: insight into the pathogenesis of irritative symptoms in benign prostatic hyperplasia and young anxious males

Recent epidemiological studies have shown that hypertensive men are more likely to undergo surgical intervention for irritative voiding symptoms from BPH than age-matched controls. Indeed, noradrenergic nerves which regulate vascular tone also participate in the functional component of bladder outlet obstruction due to BPH. Newer, less invasive therapies for BPH such as thermal therapy can relieve symptoms yet do not eliminate obstruction based on urodynamic studies. Coincidentally, drugs such as alpha-adrenoceptor antagonists, which have been thought to relieve obstruction due to a peripheral effect, can be given intrathecally in animals to relieve urinary frequency due to obstruction. Taken together these observations implicate both peripheral and central sympathetic pathways in the motor control of the urinary bladder especially with disease states. We have used the hypertensive and behaviourally hyperactive spontaneously hypertensive rat (SHR), to investigate the roles sympathetic pathways or micturition. Elevated nerve growth factor (NGF) derived from vascular and bladder smooth muscle cells of the SHR appears to direct morphological, biochemical, and functional changes. The increase in NGF can apparently be explained by stabilization of its mRNA leading to increased synthesis in NGF. Bladders from SHRs develop a profuse noradrenergic hyperinnervation compared with the control WKY strain. Since afferents supplying the SHR bladder are hypertrophied, changes in afferent pathways are also likely. These differences in innervation and NGF in the SHR may explain changes in function. SHRs void 3 times as frequently as their genetic controls. Urinary frequency can be reduced by alpha-adrenoceptor antagonists. Cystometrograms performed in SHRs reveal lower bladder capacities and micturition volumes and the presence of unstable contractions compared with the WKY rat. Intrathecal, rather than intra-arterial administration of the alpha-adrenoceptor antagonist doxazosin reduces unstable contractions in the SHR. In vitro muscle bath studies have shown enhanced responses of SHR bladder smooth muscle to alpha-adrenoceptor agonists. It is likely that upregulation of NGF production causes sensory and possibly noradrenergic pathways to elicit hyperactive voiding. Increase in NGF in the adult bladder due to pathological conditions yields similar, yet distinct, consequences for voiding behaviour and innervation. Likewise, increased NGF in adult bladders following obstruction or inflammation triggers neuronal hypertrophy, enhanced reflex activity and urinary frequency. In contrast to the SHR, hyper-innervation is not observed. Moreover, peripheral or spinal alpha-adrenoceptor blockade eliminates urinary frequency following obstruction. These observations support the role for sympathetic pathways in the motor function of the bladder, especially in congenital or adult disease states. A similar process may underlie the neuroplasticity involved in alterations after obstruction or inflammation of the lower urinary tract in humans. The SHR strain raises the possibility that a common genetic defect exists capable of predisposing to both hypertension and overactivity of the urinary bladder. Whether a genetic predisposition to sustained bladder overactivity in response to inflammatory stimuli in obstruction exists in humans is an intriguing prospect.     

Age-dependence of the spontaneous activity of the rat urinary bladder

Abnormal mechanical function of the bladder is manifested in a number of ways including higher frequency of involuntary detrusor contractions associated with reduced compliance of the bladder that is responsible for an increase in intraluminal pressure during filling. There are basically two ways to approach experimentally these problems: (1) by studying the neural control of the lower urinary tract function, and (2) by measuring the properties of smooth muscle cells in the bladder wall. Studies on smooth muscle function often do not take the origin of smooth muscle cells into account i.e., whether they were harvested from normal or overactive bladders. Although, this simplistic view may be beneficial to understanding the generation of the spontaneous activity of the bladder, however, it does not sufficiently explain the cell-to-cell propagation of the spontaneous smooth muscle activity. The spontaneous activity of smooth muscle is an important factor that works against the bladder compliance in the filling phase, and may inversely affect the neurally evoked response during micturition. The intensity of spontaneous activity is the age-dependent; it is high in neonatal bladders it is small or almost non-existent in adults and reemerges in older bladders. This review focuses on these age-dependent alterations of spontaneous bladder contractions and describes the possible mechanisms which may have important role in regulating the spontaneous contractions using the rat as an animal model.     

In vitro growth of human urinary tract smooth muscle cells on laminin and collagen type I-coated membranes under static and dynamic conditions

This study investigates in vitro growth of human urinary tract smooth muscle cells under static conditions and mechanical stimulation. The cells were cultured on collagen type I- and laminin-coated silicon membranes. Using a Flexcell device for mechanical stimulation, a cyclic strain of 0-20% was applied in a strain-stress-time model (stretch, 104 min relaxation, 15 s), imitating physiological bladder filling and voiding. Cell proliferation and alpha-actin, calponin, and caldesmon phenotype marker expression were analyzed. Nonstretched cells showed significant better growth on laminin during the first 8 days, thereafter becoming comparable to cells grown on collagen type I. Cyclic strain significantly reduced cell growth on both surfaces; however, better growth was observed on laminin. Neither the type of surface nor mechanical stimulation influenced the expression pattern of phenotype markers; alpha-actin was predominantly expressed. Coating with the extracellular matrix protein laminin improved in vitro growth of human urinary tract smooth muscle cells.     

Hepatocyte growth factor-modified adipose tissue-derived stem cells improve erectile function in streptozotocin-induced diabetic rats

Abstract

TGFβ1-Smad signaling pathway is closely related to various tissues fibrosis. Hepatocyte growth factor (HGF) has been shown to antagonize TGFβ1-Smad signaling and may improve kidney tissue fibrosis in diabetic models. Penile fibrosis is a pathological condition which occurs during diabetic erectile dysfunction (ED). The aim of this study was to examine the effect of the treatment of ED in diabetic rats with a combination of HGF and adipose tissue-derived stem cells (ADSC). In this diabetes model, rats were injected intraperitoneally with 60?mg streptozotocin (STZ) to induce diabetes. Three months later, the diabetic rats were divided into a negative control(NC) group, an ADSC-treated group and an ADSC?+?HGF-treated group while normal rats were assigned into a sham group. Rats in the sham and NC groups were injected in the corpus cavernosum with phosphate-buffered saline, while rats in the other groups were injected with either ADSC or ADSC?+?HGF. One month later, erectile function was examined in each group and penile tissues were collected for experiments. The expression of smooth muscle actin (SMA) and platelet-endothelial cell adhesion molecule-1 (PECAM-1) was analyzed by Western blotting. The smooth muscle and collagen deposition in corpus cavernosum was evaluated by Masson staining, while endothelial changes were assessed immunohistochemically. Cell apoptosis was detected by the TdT-mediated dUTP nick-end labeling (TUNEL) assay. The results revealed that ADSC alone can significantly improve erectile function in diabetic rats, but in combination with HGF the improvement was more prominent, showing higher content of smooth muscle and endothelial cells and lower cell apoptotic index in corpus cavernosum. Treatment with HGF can significantly enhance the beneficial effect of ADSC on erectile function in diabetic rats, and this effect might be closely related to the down-regulation of TGFβ1-Smad signaling.     

Extension of bladder-based organ regeneration platform for tissue engineering of esophagus

Recent successes in regenerative medicine and tissue engineering of bladder and bladder-like neo-organs have leveraged regenerative constructs composed of a biodegradable scaffold seeded with a population of smooth muscle cells. We have shown that such smooth muscle cells are isolatable from adipose and other sources alternate to the primary organ. We hypothesize that this regenerative platform is not limited to regeneration of bladder and bladder-like neo-organs, but rather represents a foundational technology platform broadly applicable for regeneration of laminarly organized hollow organs. Using esophagus as an illustrative example in support of this hypothesis, we demonstrate that patch constructs composed of adipose-derived smooth muscle cells seeded on a biodegradable matrix catalyze complete regeneration of the esophageal wall in a rodent model of esophageal injury. By implication, such regenerative constructs may potentially be used to mediate the regeneration of any laminarly organized tubular organ.     

Hypoxia preconditioning attenuates bladder overdistension-induced oxidative injury by up-regulation of Bcl-2 in the rat

We explored whether hypoxic preconditioning minimizes oxidative injury induced by overdistension/emptying in the rat bladder. For hypoxic preconditioning, female Wistar rats were placed in a hypobaric chamber (380 Torr) 15 h day⁻¹ for 28 days. Overdistension was induced by infusion of two times the threshold volume of saline into the bladder and was maintained for 1 or 2 h, followed by drainage/emptying. During overdistension (ischaemia) and emptying (reperfusion) periods, a bursting increase of reactive oxygen species (ROS) from the bladder was originated from the large numbers of infiltrating leucocytes and scattered resident cells, including urothelial, submucosal, and smooth muscle cells. ROS impaired the voiding function by a reduction of bladder afferent and efferent nerve activity and bethanecol- or ATP-induced detrusor contraction. ROS enhanced pro-apoptotic mechanisms, including increases in the Bax/Bcl-2 ratio, CPP32 expression, and poly(ADP-ribose) polymerase (PARP) fragments with subsequent apoptotic cell formation in the insulted bladders. Hypoxia preconditioning up-regulated Bcl-2 expression in the bladder and significantly reduced the levels of ROS and apoptosis detected in the overdistension/emptying bladders and preserved partial voiding function. Bcl-2 up-regulation by hypoxia preconditioning contributes protection against overdistension/emptying-induced oxidative stress and injury in the bladder.     

Quantification of Bladder Smooth Muscle Orientation in Normal and Spinal Cord Injured Rats

Spinal cord injuries (SCI) often lead to severe bladder dysfunctions. Our previous studies have demonstrated that following SCI, rat bladder wall tissue became hypertrophied, significantly more compliant, and changed its mechanical behavior from orthotropic to isotropic. In order to elucidate the link between the tissue microstructure and mechanical properties of the wall, we have developed a novel semi-automated image analysis method to quantify smooth muscle bundle orientation and mass fraction in the bladder wall tissues from normal and 10 day-post-SCI rats. Results of the present study revealed that there were significant (p < 0.05) increases in smooth muscle area fractions as well as significantly (p < 0.001) fewer cell nuclei per muscle area in the SCI groups compared to the normal groups. Furthermore, while the normal rat bladders exhibited predominant smooth muscle orientation only in the longitudinal direction, the SCI rat bladders exhibited smooth muscles oriented in both the circumferential and longitudinal directions. These results provide first evidence that bladder smooth muscle cells exhibit hypertrophy rather than hyperplasia and developed a second, orthogonal orientation of smooth muscle bundles following SCI. The results of the present study corroborate our previous mechanical anisotropy data and provide the basis for development of structure-based constitutive models for urinary bladder wall tissue.     

平滑肌细胞在旋转生物反应器内的微载体培养与快速扩增

为获取足量数量活性良好的膀胱平滑肌种子细胞，本实验探索在旋转生物反应器内应用微载体技术快速扩增膀胱平滑肌细胞的方法。将培养的第二代新西兰兔膀胱不滑肌细胞应用Cytodex-3微载体在旋转生物反应器（RCCS）内进行动态培养，观测平滑肌细胞的生长情况和细胞代谢率，进行a-肌动蛋白免疫组化染色，并与常规方法培养平滑肌细胞进行比较。结果显示膀胱平滑肌细胞在Cytodex-3微载体上生长迅速、细胞代谢率高、生长倍增时间缩短。在培养第九天，细胞数量可达最初接种的23倍。免疫组化显示平滑肌细胞活性良好。结果表明利用微载体细胞培养技术可简便快速地在体外扩增平滑肌细胞，可为构建组织工程化人造膀胱提供大量活性良好的平滑肌细胞。     

Biphasic effect of apomorphine,an anti-parkinsonian drug,on bladder function in rats

The effects of anti-parkinsonian drugs on bladder function have been controversial; namely, some aggravated while others alleviated bladder dysfunction in patients with Parkinson disease. These studies, however, did not consider the dose- and time-dependent effects. Therefore, we investigated these effects of apomorphine, an anti-parkinsonian drug and a nonselective dopamine receptor agonist, on the bladder function using normal conscious rats. Consecutive cycles of micturition were analyzed for 30-min periods before and after (over a 4-h period) s.c. administration of a single dose of 0.01 (low), 0.05 (medium), 0.5 (high) mg/kg of apomorphine or saline to the rats. Apomorphine administration produced various effects in relevant urodynamic parameters, although the monitored parameters remained unchanged in saline-administered rats. During filling, low-dose apomorphine induced initial decreases in voiding frequency (VF; defined as the number of voidings during a 15-min period). However, medium- and high-dose apomorphine dose-dependently induced initial increases in VF, and was followed by decreases in VF. These doses also induced initial increase in threshold pressure. During voiding, low-dose apomorphine induced initial increases in micturition volume (MV), which reflected an increase in bladder capacity (BC). However, medium- and high-dose apomorphine dose-dependently induced initial decreases in MV, and was followed by increases in MV. These doses also dose-dependently induced an initial increase in maximum bladder contraction pressure during the early phase after administration. The present study demonstrated that apomorphine displayed a dose- and time-dependent biphasic effect on the normal bladder filling function. These pharmacodynamic characteristics of apomorphine could be applicable to other anti-parkinsonian drugs such as levodopa and nonselective dopamine receptor agonists, and may account for the previous reported conflicting effects of anti-parkinsonian drugs on bladder dysfunction in patients with Parkinson disease, although it needs to be evaluated in disease status.     

Restoration of bladder contraction by bone marrow transplantation in rats with underactive bladder

We attempted to increase bladder contraction by bone marrow cell transplantation in rats with underactive bladder due to bladder outlet obstruction (BOO). Twelve female rats were anesthetized with halothane to create BOO. After 1 month, the urethral obstruction was removed and they were divided into a transplant group and a sham-operated group (n = 6 each). Bone marrow cells (1 x 10(7) / 0.2 mL) isolated from green fluorescent protein transgenic rats were injected into the bladder wall of the transplant group. Rats from the sham-operated group received injection of culture medium alone. One month after transplantation, isovolumetric cystometry parameters and histological features of bladder were observed as well as intact control rats (n = 6). The amplitude of bladder contractions was larger and the interval between contractions was shorter in the transplant group than the sham-operated group, and there were no differences in these parameters between the transplant group and the control group. Some green fluorescent muscle layers were found in the bladder wall of the transplant group, and these layers were also labeled by anti alpha-smooth muscle actin antibody. These results suggest that transplanted bone marrow cells may improve bladder contractility by differentiating into smooth muscle-like cells.     

Physiological and pathophysiological implications of micromotion activity in urinary bladder function

‘Micromotions’ is a term signifying the presence of localized microcontractions and microelongations, alongside non‐motile areas. The motile areas tend to shift over the bladder surface with time, and the intravesical pressure reflects moment‐by‐moment summation of the interplay between net contractile force generated by micromotions and general bladder tone. Functionally, the bladder structure may comprise modules with variable linkage, which supports presence of localized micromotions (no functional linkage between modules), propagating contractions (where emergence of linkage allows sequential activation) and the shifting of micromotions over time. Detrusor muscle, interstitial cells and intramural innervation have properties potentially relevant for initiating, coordinating and modulating micromotions. Conceptually, such activity could facilitate the generation of afferent activity (filling state reporting) in the absence of intravesical pressure change and the ability to transition to voiding at any bladder volume. This autonomous activity is an intrinsic property, seen in various experimental contexts including the clinical setting of human (female) overactive bladder. ‘Disinhibited autonomy’ may explain the obvious micromotions in isolated bladders and perhaps contribute clinically in neurological disease causing detrusor overactivity. Furthermore, any process that could increase the initiation or propagation of microcontractions might be anticipated to have a functional effect, increasing the likelihood of urinary urgency and detrusor overactivity respectively. Thus, models of bladder outlet obstruction, neurological trauma and ageing provide a useful framework for detecting cellular changes in smooth muscle, interstitial cells and innervation, and the consequent effects on micromotions.