The role of inflammatory mediators in the overactive and bladder pain syndromes

The Overactive Bladder (OAB) and Bladder Pain Syndrome (BPS) are debilitating disorders for which the pathophysiological mechanisms are poorly understood. Injury or dysfunction of the protective urothelial barrier layer, specifically the proteoglycan composition and number, has been proposed as the primary pathological characteristic of BPS. For OAB, the myogenic theory with dysfunction of the muscarinic receptors is the most reiterated hypothesis. For both over activity of the inflammatory response has been posited to play a major role in these diseases. We hypothesise that BPS and OAB are peripheral sensory disorders, with an increase in inflammatory mediators, such as cytokines and chemokines, which are capable of activating, either directly or indirectly, sensory nerve activity causing the disease. The aim of the PhD is to identify potential new therapeutic targets for the treatment of BPS and OAB. We used medium throughput quantitative gene expression analysis of 96 inflammation associated mediators to measure gene expression levels in BPS and OAB bladder biopsies and compared them to control samples. Then we created a novel animal model of disease by specific proteoglycan deglycosylation of the bladder mucosal barrier, using the bacterial enzymes Chondroitinase ABC and Heparanase III. These enzymes specifically remove the glycosaminoglycan side chains from the urothelial proteoglycan molecules. We tested role of the identified mediators in this animal model. In addition, in order to determine on which patients peripheral treatment strategies may work, we assessed the effect of local anaesthetics on patients with bladder pain. Gene expression analysis did not reveal a difference in inflammatory genes in the OAB versus control biopsies. However, several genes were upregulated in BPS versus control samples, from which two genes, FGF7 and CLL21 were correlated with patient clinical phenotypes for ICS/PI symptom and problem indices respectively. In order to determine which patients are likely to respond to treatment, we sought to characterise the bladder pain in BPS patients. Using urodynamics and local anaesthetics, we differentiated patients with peripherally mediated pain and patients with central sensitisation of their pain. Finally to determine the role of these mediators in bladder pain, we created an animal model of disease, which specifically replicates the human pathology: namely disruption in the barrier proteoglycan molecules. CCL21 led to an increase in painrelated behaviour, while FGF7 attenuated this behaviour, as measured by cystometry, spinal c-fos expression and mechanical withdrawal threshold examination. In conclusion, we have identified CCL21 and FGF7 as potential targets for the treatment of BPS. Manipulation of these ligands or their receptors may prove to be valuable previously unexploited targets for the treatment of BPS

Effect of early tranexamic acid administration on mortality, hysterectomy, and other morbidities in women with post-partum haemorrhage (WOMAN): an international, randomised, double-blind, placebo-controlled trial

Background Post-partum haemorrhage is the leading cause of maternal death worldwide. Early administration of tranexamic acid reduces deaths due to bleeding in trauma patients. We aimed to assess the effects of early administration of tranexamic acid on death, hysterectomy, and other relevant outcomes in women with post-partum haemorrhage. Methods In this randomised, double-blind, placebo-controlled trial, we recruited women aged 16 years and older with a clinical diagnosis of post-partum haemorrhage after a vaginal birth or caesarean section from 193 hospitals in 21 countries. We randomly assigned women to receive either 1 g intravenous tranexamic acid or matching placebo in addition to usual care. If bleeding continued after 30 min, or stopped and restarted within 24 h of the first dose, a second dose of 1 g of tranexamic acid or placebo could be given. Patients were assigned by selection of a numbered treatment pack from a box containing eight numbered packs that were identical apart from the pack number. Participants, care givers, and those assessing outcomes were masked to allocation. We originally planned to enrol 15 000 women with a composite primary endpoint of death from all-causes or hysterectomy within 42 days of giving birth. However, during the trial it became apparent that the decision to conduct a hysterectomy was often made at the same time as randomisation. Although tranexamic acid could influence the risk of death in these cases, it could not affect the risk of hysterectomy. We therefore increased the sample size from 15 000 to 20 000 women in order to estimate the effect of tranexamic acid on the risk of death from post-partum haemorrhage. All analyses were done on an intention-to-treat basis. This trial is registered with ISRCTN76912190 (Dec 8, 2008); ClinicalTrials.gov, number NCT00872469; and PACTR201007000192283. Findings Between March, 2010, and April, 2016, 20 060 women were enrolled and randomly assigned to receive tranexamic acid (n=10 051) or placebo (n=10 009), of whom 10 036 and 9985, respectively, were included in the analysis. Death due to bleeding was significantly reduced in women given tranexamic acid (155 [1·5%] of 10 036 patients vs 191 [1·9%] of 9985 in the placebo group, risk ratio [RR] 0·81, 95% CI 0·65–1·00; p=0·045), especially in women given treatment within 3 h of giving birth (89 [1·2%] in the tranexamic acid group vs 127 [1·7%] in the placebo group, RR 0·69, 95% CI 0·52–0·91; p=0·008). All other causes of death did not differ significantly by group. Hysterectomy was not reduced with tranexamic acid (358 [3·6%] patients in the tranexamic acid group vs 351 [3·5%] in the placebo group, RR 1·02, 95% CI 0·88–1·07; p=0·84). The composite primary endpoint of death from all causes or hysterectomy was not reduced with tranexamic acid (534 [5·3%] deaths or hysterectomies in the tranexamic acid group vs 546 [5·5%] in the placebo group, RR 0·97, 95% CI 0·87-1·09; p=0·65). Adverse events (including thromboembolic events) did not differ significantly in the tranexamic acid versus placebo group. Interpretation Tranexamic acid reduces death due to bleeding in women with post-partum haemorrhage with no adverse effects. When used as a treatment for postpartum haemorrhage, tranexamic acid should be given as soon as possible after bleeding onset. Funding London School of Hygiene & Tropical Medicine, Pfizer, UK Department of Health, Wellcome Trust, and Bill & Melinda Gates Foundation

The expression of inflammatory mediators in bladder pain syndrome

Background: Bladder pain syndrome (BPS) pathology is poorly understood. Treatment strategies are empirical, with limited efficacy, and affected patients have diminished quality of life. Objective: We examined the hypothesis that inflammatory mediators within the bladder contribute to BPS pathology. Design, setting, and participants: Fifteen women with BPS and 15 women with stress urinary incontinence without bladder pain were recruited from Cork University Maternity Hospital from October 2011 to October 2012. During cystoscopy, 5-mm bladder biopsies were taken and processed for gene expression analysis. The effect of the identified genes was tested in laboratory animals. Outcome measures and statistical analysis: We studied the expression of 96 inflammation-related genes in diseased and healthy bladders. We measured the correlation between genes and patient clinical profiles using the Pearson correlation coefficient. Results and limitations: Analysis revealed 15 differentially expressed genes, confirmed in a replication study. FGF7 and CCL21 correlated significantly with clinical outcomes. Intravesical CCL21 instillation in rats caused increased bladder excitability and increased c-fos activity in spinal cord neurons. CCL21 atypical receptor knockout mice showed significantly more c-fos upon bladder stimulation with CCL21 than wild-type littermates. There was no change in FGF7-treated animals. The variability in patient samples presented as the main limitation. We used principal component analysis to identify similarities within the patient group. Conclusions: Our study identified two biologically relevant inflammatory mediators in BPS and demonstrated an increase in nociceptive signalling with CCL21. Manipulation of this ligand is a potential new therapeutic strategy for BPS. Patient summary: We compared gene expression in bladder biopsies of patients with bladder pain syndrome (BPS) and controls without pain and identified two genes that were increased in BPS patients and correlated with clinical profiles. We tested the effect of these genes in laboratory animals, confirming their role in bladder pain. Manipulating these genes in BPS is a potential treatment strategy

Conjunctival Interleukin-13 Expression in Mucous Membrane Pemphigoid and Functional Effects of Interleukin-13 on Conjunctival Fibroblasts in Vitro

Interleukin-13 (IL-13) is the dominant effector cytokine of fibrosis in pulmonary and liver disease. Excessive conjunctival fibrosis in the immunobullous disease ocular mucous membrane pemphigoid (MMP) causes blindness; the pathogenesis of scarring in this disease is incompletely understood. To determine whether IL-13 is involved in conjunctival fibrosis in MMP, we studied the expression of IL-13 in ocular MMP patients before and after systemic immunosuppression and examined the effects of IL-13 on normal human conjunctival fibroblasts. We found high stromal cell expression of IL-13 in active ocular MMP by immunohistochemistry; 80% of these cells were CD3-positive T cells. Following immunosuppression, in clinically uninflamed, treated, ocular MMP patients, the number of IL-13 positive cells was significantly reduced, but this was still fourfold greater than in normal conjunctiva. IL-13 stimulated collagen lattice contraction and migration, and decreased production of mmp-3 and mmp-10 by human conjunctival fibroblasts. The addition of T cell culture supernatant to IL-13 synergistically augmented fibroblast migration. IL-13 also up-regulated surface expression of HLA-DR, CD80, CD40, and CD154 by conjunctival fibroblasts, suggesting a potential mechanism for fibroblast-T cell cross talk, via which fibroblasts may actively engage in perpetuating chronic inflammation and continued fibrosis. Together, these findings suggest that IL-13 is involved in conjunctival fibrosis in MMP, and that IL-13 has both profibrotic and pro-inflammatory effects on human conjunctival fibroblasts

Profibrotic Phenotype of Conjunctival Fibroblasts from Mucous Membrane Pemphigoid

Ocular mucous membrane pemphigoid is an immunobullous disease in which excessive conjunctival fibrosis causes blindness, and the pathogenesis of scarring is incompletely understood. To establish whether profibrotic fibroblasts with an altered phenotype exist in ocular mucous membrane pemphigoid, we compared the functional characteristics of pemphigoid conjunctival fibroblasts to normal conjunctival fibroblasts with respect to cell division; migration; collagen contraction; matrix metalloproteinase, secretion of collagen and chemokines; and myofibroblast differentiation. We found that pemphigoid fibroblasts showed increased cell division (P = 0.01), increased migration in serum-free medium (72 ± 18 migrated cells versus 33 ± 11, P = 0.04), increased collagen contraction in the presence of 10 ng/ml tumor necrosis factor-α, increased collagen type I secretion (P = 0.03), increased secretion of matrix metalloproteinase-3 (P = 0.03), and increased secretion of eotaxin in response to interleukin-13 (P = 0.04). Differences between pemphigoid and normal conjunctival fibroblasts with respect to collagen contraction and MMP secretion in the presence of interleukin-13 were also observed. Together, these findings indicate that pemphigoid conjunctival fibroblasts have a profibrotic phenotype that is maintained in vitro. No differences between pemphigoid fibroblasts obtained from acutely inflamed versus clinically uninflamed conjunctiva were observed. Developing effective antifibrotic therapies will require understanding of the mechanisms that both induce and maintain the profibrotic phenotype