The bladder undergoes large shape changes as it fills and empties and experiences complex mechanical forces. These forces become abnormal in diseases of the lower urinary tract such as overactive bladder, neurogenic bladder, and urinary retention. As the primary mechanosensors linking the actin cytoskeleton to the extracellular matrix (ECM), integrins are likely to play vital roles in maintaining bladder smooth muscle (BSM) homeostasis. In a tamoxifen-inducible smooth muscle conditional knockout of β1-integrin, there was concomitant loss of α1- and α3-integrins from BSM and upregulation of αV- and β3-integrins. Masson's staining showed a reduction in smooth muscle with an increase in collagenous ECM. Functionally, mice exhibited a changing pattern of urination by voiding spot assay up to 8 wk after tamoxifen. By 8 wk, there was increased frequency with reductions in voided volume, consistent with overactivity. Cystometrograms confirmed that there was a significant reduction in intercontractile interval with reduced maximal bladder pressure. Muscle strip myography revealed a loss of contraction force in response to electrical field stimulation, that was entirely due to the loss of muscarinic contractility. Quantitative western blotting showed a loss of M3 receptor and no change in P2X1. qPCR on ECM and interstitial genes revealed loss of Ntpd2, a marker of an interstitial cell subpopulation; and an upregulation of S100A4, which is often associated with fibroblasts. Collectively, the data show that the loss of appropriate mechanosensation through integrins results in cellular and extracellular remodeling, and concomitant bladder dysfunction that resembles lower urinary tract symptoms seen in older people.
Publications
2022
Diabetic bladder dysfunction (DBD) is the most common complication in diabetes. Myogenic abnormalities are common in DBD; however, the underlying mechanisms leading to these remain unclear. To understand the importance of smooth muscle insulin receptor (IR)-mediated signaling in the pathogenesis of DBD, we conditionally deleted it to achieve either heterozygous (SMIR+/-) or homozygous (SMIR-/-) deletion in smooth muscle cells. Despite impaired glucose and insulin tolerance seen with SMIR-/- mice, both SMIR+/- and SMIR-/- mice exhibited normal blood glucose and plasma insulin levels. Interestingly, these mice had abnormal voiding phenotypes, that included urinary frequency and small voids, and bladder smooth muscle (BSM) had significantly diminished contraction force. Morphology revealed a dilated bladder with thinner BSM layer, and BSM bundles were disorganized with penetrating interstitial tissue. Deletion of IR elevated FoxO and decreased mTOR protein expression, which further decreased the expression of Chrm3, P2x1, Sm22, and Cav1.2, crucial functional proteins for BSM contraction. Furthermore, we determined the expression of adiponectin in BSM, and deletion of IR in BSM inhibited adiponectin-mediated signaling. In summary, disruption of IR-mediated signaling in BSM caused abnormalities in proliferation and differentiation, leading to diminished BSM contractility and a voiding dysfunction phenotype that recapitulates human DBD.
Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic inflammatory disease without consistently effective treatment. Among the many mediators implicated in cystitis, the overproduction of reactive oxygen species (ROS) seems to play a key role, although the main source of ROS remains unclear. This study aimed to investigate the contribution of NADPH oxidase (NOX) isoforms in ROS generation and the voiding dysfunction of cyclophosphamide (CYP, 300 mg/Kg, ip, 24 h)-induced cystitis in adult female mice, a well-recognized animal model to study IC/BPS, by using GKT137831 (5 mg/Kg, ip, three times in a 24 h period) or GSK2795039 (5 mg/Kg, ip, three times in a 24 h period) to inhibit NOX1/4 or NOX2, respectively. Our results showed that treatment with GSK2795039 improved the dysfunctional voiding behavior induced by CYP, reduced bladder edema and inflammation, and preserved the urothelial barrier integrity and tight junction occludin expression, besides inhibiting the characteristic vesical pain and bladder superoxide anion generation. In contrast, the NOX1/4 inhibitor GKT137831 had no significant protective effects. Taken together, our in vivo and ex vivo data demonstrate that NOX2 is possibly the main source of ROS observed in cystitis-induced CYP in mice. Therefore, selective inhibition of NOX2 by GSK2795039 may be a promising target for future therapies for IC/BPS.
Complementary DNAs (cDNAs) for two aquaporin water channel genes (AQP3 and AQP15) were amplified cloned and sequenced to initiate this study. Northern blot analysis was carried out to confirm the mRNA sizes of these AQP genes with AQP3 mRNA bands exhibiting sizes of 1.2 and 1.6 k bases and AQP15 had a mRNA band of 2.1 k bases. Northern blot analysis was also performed on kidney and esophagus total RNA samples from fish acclimated to 75%, 100% or 120% seawater (SW). The level of AQP15 mRNA expression was shown to significantly decrease following salinity acclimation from 100 to 120% SW. An opposite but non-significantly different trend was observed for AQP3 mRNA levels. Full length cDNAs were then used to generate AQP3 and AQP15 mRNAs for microinjection into Xenopus oocytes. Both AQP3- and AQP15- microinjected oocytes exhibited significantly elevated apparent water permeability compared to control oocytes at neutral pH. The apparent water permeability was mercury-inhibitable, significantly so in the case of AQP3. AQP3 microinjected oocytes showed pH sensitivity in their apparent water permeability, showing a lack of permeability at acidic pH values. The Carboxyl-terminal derived amino acid sequences of AQP3 and AQP15 were used to generate rabbit affinity-purified polyclonal antibodies. Western blots with the antibodies showed a band of 31.3 kDa for AQP3 in the kidney, with minor bands at 26, 24 and 21 kDa. For AQP15 a band of 26 kDa was seen in gill and kidney. Fainter bands at 28 and 24 kDa were also seen in the kidney. There was also some higher molecular weight banding. None of the bands were seen when the antibodies were pre- blocked with their peptide antigens. Immunohistochemical localization studies were also performed in the gill and spiral valve intestine. In the gill, AQP15 antibody staining was seen sporadically in the membranes of surface epithelial cells of the secondary lamellae. Tyramide amplification of signals was employed in the spiral valve intestine. Tyramide-amplified AQP3 antibody staining was observed in the basal membrane of the invaginated epithelial cell layer of secondary intestinal folds in luminal surface of either the side wall of the spiral valve intestine or in internal valve tissue 'flaps'. For the AQP15 antibody, tyramide-amplified staining was instead found on the apical and to a lesser extent the lateral membranes of the same invaginated epithelial cell layer. The localization of AQP3 and AQP15 in the spiral valve intestine suggests that a trans-cellular water absorption pathway may exist in this tissue.
CONTEXT: The role of urodynamic studies (UDSs) in the diagnosis of lower urinary tract symptoms (LUTS) is crucial. Although expert statements and guidelines underline their value for clinical decision-making in various clinical settings, the academic debate as to their impact on patient outcomes continues.
OBJECTIVE: To summarise the evidence from all randomised controlled trials assessing the clinical usefulness of UDS in the management of LUTS.
EVIDENCE ACQUISITION: For this systematic review, searches were performed without language restrictions in three electronic databases until November 18, 2020. The inclusion criteria were randomised controlled study design and allocation to receive UDS or not prior to any clinical management. Quality assessment was performed by two reviewers independently, using the Cochrane Collaboration's tool for assessing the risk of bias. A random-effect meta-analysis was performed on the uniformly reported outcome parameters.
EVIDENCE SYNTHESIS: Eight trials were included, and all but two focused on women with pure or predominant stress urinary incontinence (SUI). A meta-analysis of six studies including 942 female patients was possible for treatment success, as defined by the authors (relative risk 1.00, 95% confidence interval: 0.93-1.07), indicating no difference in efficacy when managing women with UDS.
CONCLUSIONS: Although UDSs are not replaceable in diagnostics, since there is no other equivalent method to find out exactly what the lower urinary tract problem is, there are little data supporting its impact on outcomes. Randomised controlled trials have focussed on a small group of women with uncomplicated SUI and showed no added value, but these findings cannot be extrapolated to the overall patient population with LUTS, warranting further well-designed trials.
PATIENT SUMMARY: Despite urodynamics being the gold standard to assess lower urinary tract symptoms (LUTS), as it is the only method that can specify lower urinary tract dysfunction, more studies assessing the clinical usefulness of urodynamic studies (UDSs) in the management of LUTS are needed. UDS investigation is not increasing the probability of success in the treatment of stress urinary incontinence.
Severe spinal cord injuries result in permanent paraparesis in spite of the frequent sparing of small portions of white matter. Spared fibre tracts are often incapable of maintaining and modulating the activity of lower spinal motor centres. Effects of rehabilitative training thus remain limited. Here, we activated spared descending brainstem fibres by electrical deep brain stimulation of the cuneiform nucleus of the mesencephalic locomotor region, the main control centre for locomotion in the brainstem, in adult female Lewis rats. We show that deep brain stimulation of the cuneiform nucleus enhances the weak remaining motor drive in highly paraparetic rats with severe, incomplete spinal cord injuries and enables high-intensity locomotor training. Stimulation of the cuneiform nucleus during rehabilitative aquatraining after subchronic (n = 8 stimulated versus n = 7 unstimulated versus n = 7 untrained rats) and chronic (n = 14 stimulated versus n = 9 unstimulated versus n = 9 untrained rats) spinal cord injury re-established substantial locomotion and improved long-term recovery of motor function. We additionally identified a safety window of stimulation parameters ensuring context-specific locomotor control in intact rats (n = 18) and illustrate the importance of timing of treatment initiation after spinal cord injury (n = 14). This study highlights stimulation of the cuneiform nucleus as a highly promising therapeutic strategy to enhance motor recovery after subchronic and chronic incomplete spinal cord injury with direct clinical applicability.
CONTEXT: Controversy still exists regarding the balance of benefits and harms for the different surgical options for neurogenic stress urinary incontinence (N-SUI).
OBJECTIVE: To identify which surgical option for N-SUI offers the highest cure rate and best safety without compromising urinary tract function and bladder management.
EVIDENCE ACQUISITION: A systematic review was performed under the auspices of the European Association of Urology Guidelines Office and the European Association of Urology Neuro-Urology Guidelines Panel according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement.
EVIDENCE SYNTHESIS: A total of 32 studies were included. Overall, 852 neurourological patients were surgically treated for N-SUI. The treatment offered most often (13/32 studies) was an artificial urinary sphincter (AUS; 49%, 416/852) and was associated with a need for reintervention in one-third of patients. More than 200 surgical revisions were described. Overall, 146/852 patients (17%) received concomitant bladder augmentation, mainly during placement of an AUS (42%, 62/146) or autologous sling (34% of women and 14% of men). Following pubovaginal sling placement, dryness was achieved in 83% of cases. A significant improvement in N-SUI was observed in 87% (82/94) of women following placement of a synthetic midurethral sling. Efficacy after insertion of an adjustable continence therapy device (ACT 40%, proACT 60%) was reported for 38/128 cases (30%). The cure rate for bulking agents was 35% (9/25) according to 2/32 studies, mainly among men (90%). The risk of bias was highly relevant. Baseline and postoperative cystometry were missing in 13 and 28 studies, respectively.
CONCLUSIONS: The evidence is mainly reported in retrospective studies. More than one intervention is often required to achieve continence because of coexisting neurogenic detrusor overactivity, low compliance, or the onset of complications in the medium and long term. Urodynamic data are needed to better clarify the success of N-SUI treatment with the different techniques.
PATIENT SUMMARY: Our review shows that insertion of an artificial urinary sphincter for urinary incontinence is effective but is highly associated with a need for repeat surgery. Other surgical options may have lower continence rates or a risk of requiring intermittent catheterization, which patients should be informed about before deciding on surgery for their incontinence.
2021
Lower urinary tract dysfunction affects a multitude of patients. Current therapeutic approaches are limited and very little is known about the mechanisms in failure of bladder control. Thus, more basic research is clearly needed to elucidate the underlying pathological mechanisms and to develop novel treatment strategies in urology. Noninvasive tests such as the void-spot assay and the metabolic cage and more invasive urodynamics investigations are currently used to assess lower urinary tract function in animals, in particular rodents. The noninvasive tests give some insights into the functionality of the system, whereas urodynamics testing yields an objective evaluation that allows distinction of different pathologies and investigations of the underlying neuronal malfunctions. PATIENT SUMMARY: We briefly summarize methods currently used to assess impairments of bladder function in animal models. Both noninvasive and invasive methods are available and can be used to understand and improve human health. An accurate and detailed diagnosis is, however, possible only with urodynamics assessments.
Traumatic brain injury (TBI) is the leading cause of mortality and disability in young people and may lead to the development of progressive neurodegeneration, such as that observed in chronic traumatic encephalopathy. We have recently found that the conformation-specific cis phosphorylated form of tau (cis P-tau) is a major early driver of neurodegeneration after TBI. However, not much is known about how cis P-tau is regulated in TBI. In this study, we demonstrated a novel critical role of death-associated protein kinase 1 (DAPK1) in regulating cis P-tau induction after TBI. We found that DAPK1 is significantly upregulated in mouse brains after TBI and subsequently promotes cis P-tau induction. Genetic deletion of DAPK1 in mice not only significantly decreases cis P-tau expression, but also effectively attenuates neuropathology development and rescues behavioral impairments after TBI. Mechanistically, DAPK1-mediated cis P-tau induction is regulated by the phosphorylation of Pin1 at Ser71, a unique prolyl isomerase known to control the conformational status of P-tau. Furthermore, pharmacological suppression of DAPK1 kinase activity dramatically decreases the levels of Pin1 phosphorylated at Ser71 as well as cis P-tau after neuronal stress. Thus, DAPK1 is a novel regulator of TBI that, in combination with its downstream targets, has a major impact on the development and/or outcome of TBI, and targeting DAPK1 might offer a potential therapeutic impact on TBI-related neurodegenerative diseases.
Compelling evidence supports vascular contributions to cognitive impairment and dementia (VCID) including Alzheimer's disease (AD), but the underlying pathogenic mechanisms and treatments are not fully understood. Cis P-tau is an early driver of neurodegeneration resulting from traumatic brain injury, but its role in VCID remains unclear. Here, we found robust cis P-tau despite no tau tangles in patients with VCID and in mice modeling key aspects of clinical VCID, likely because of the inhibition of its isomerase Pin1 by DAPK1. Elimination of cis P-tau in VCID mice using cis-targeted immunotherapy, brain-specific Pin1 overexpression, or DAPK1 knockout effectively rescues VCID-like neurodegeneration and cognitive impairment in executive function. Cis mAb also prevents and ameliorates progression of AD-like neurodegeneration and memory loss in mice. Furthermore, single-cell RNA sequencing revealed that young VCID mice display diverse cortical cell type-specific transcriptomic changes resembling old patients with AD, and the vast majority of these global changes were recovered by cis-targeted immunotherapy. Moreover, purified soluble cis P-tau was sufficient to induce progressive neurodegeneration and brain dysfunction by causing axonopathy and conserved transcriptomic signature found in VCID mice and patients with AD with early pathology. Thus, cis P-tau might play a major role in mediating VCID and AD, and antibody targeting it may be useful for early diagnosis, prevention, and treatment of cognitive impairment and dementia after neurovascular insults and in AD.