Autoimmunity to urothelial antigen causes bladder inflammation, pelvic pain and voiding dysfunction: a novel animal model for Hunner type interstitial cystitis

Recent evidence revealed that Hunner type interstitial cystitis (HIC) is a robust inflammatory disease potentially associated with enhanced immune responses and histologically characterized by epithelial denudation and lymphoplasmacytic infiltration with frequent clonal expansion of infiltrating B cells. To date, few animal models that reproduce the histological and clinical correlates of HIC have yet been established. In the present study, we aimed to develop a novel animal model for HIC via autoimmunity to the bladder urothelium using the transgenic mouse model (URO-OVA) that expresses the membrane form of the model antigen ovalbumin (OVA) as a self-antigen on the bladder urothelium. OVA-specific lymphocytes (splenocytes) were generated by immunization of C57BL/6 mice with OVA protein and injected intravenously into URO-OVA mice. The splenocytes from OVA-immunized C57BL/6 mice showed increased IFN-γ production in response to OVA stimulation in vitro. URO-OVA mice adoptively transferred with OVA-primed splenocytes developed cystitis exhibiting histological chronic inflammatory changes such as remarkable mononuclear cell infiltration predominantly composed of T and B lymphocytes, increased vascularity, and mucosal hyperemia in the bladder at days 7-28 with a peak at day 21 tested. No systemic inflammation was found in cystitis-induced URO-OVA mice, nor was any inflammation found in wild-type C57BL/6 mice adoptively transferred with OVA-primed splenocytes. Along with bladder inflammation, URO-OVA mice demonstrated significantly increased pelvic nociceptive responses, voiding dysfunction, and upregulated mRNA expression levels for IFN-γ, TNF-α and substance P precursor in the bladder. This model reproduces the histological and clinical features of human HIC, providing a novel model for HIC research.

Urinary Canthariasis Due to Tenebrio molitor Larva in a Ten-Year-Old Boy

Canthariasis is a human disease caused by infestation of beetle larvae. We report here an unusual cause of urogenital in-fection due to Tenebrio molitor in a 10-year-old boy suffering from severe and intermittent suprapubic pain from Nehban-dan City, Northeastern Iran in 2018. After 9 months, three larvae were excreted. Keratinization of bladder wall was ob-served in histopathology. All laboratory evaluations were normal except for presence of microscopic hematuria. This re-port implicated that T. molitor could infest bladder accidentally and cause canthariasis and clinical symptoms that may lead to severe pain and bladder inflammation and hyperemia.

Experimental Cannabinoid 2 Receptor Activation by Phyto-Derived and Synthetic Cannabinoid Ligands in LPS-Induced Interstitial Cystitis in Mice

Interstitial cystitis (IC) is a chronic bladder disorder with unclear etiology. The endocannabinoid system has been identified as a key regulator of immune function, with experimental evidence for the involvement of cannabinoid receptors in bladder inflammation. This study used intravital microscopy (IVM) and behavioral testing in lipopolysaccharide-induced IC, to investigate the anti-inflammatory analgesic effects of a natural dietary sesquiterpenoid, beta-caryophyllene (BCP), which is present in cannabis among other plants, and has reported agonist actions at the cannabinoid 2 receptor (CB2R). BCP’s anti-inflammatory actions were compared to the synthetic CB2R-selective cannabinoid, HU308, and to an FDA-approved clinical treatment (dimethyl sulfoxide: DMSO). IVM data revealed that intravesical instillation of BCP and/or HU308 significantly reduces the number of adhering leukocytes in submucosal bladder venules and improves bladder capillary perfusion. The effects of BCP were found to be comparable to that of the selective CB2R synthetic cannabinoid, HU308, and superior to intravesical DMSO treatment. Oral treatment with BCP was also able to reduce bladder inflammation and significantly reduced mechanical allodynia in experimental IC. Based on our findings, we believe that CB2R activation may represent a viable therapeutic target for IC, and that drugs that activate CB2R, such as the generally regarded as safe (GRAS) dietary sesquiterpenoid, BCP, may serve as an adjunct and/or alternative treatment option for alleviating symptoms of inflammation and pain in the management of IC.

Tertiary lymphoid tissue develops during normal aging in mice and humans

ABSTRACTAging has multifaceted effects on the immune system in the context of systemic responses to specific vaccines and pathogens, but how aging affects tissue-specific immunity is not well-defined. Chronic bladder inflammation is highly prevalent in older women, but mechanisms by which aging promotes these pathologies remain unknown. Here we report distinct, age-associated changes to the immune compartment in the otherwise normal female (but not in male) mouse urinary bladder and parallel changes in older women with chronic bladder inflammation. In aged mice, the bladder epithelium became more permeable, and the homeostatic immune landscape shifted from a limited, innate immune-predominant surveillance to an inflammatory, adaptive immune-predominant environment. Strikingly, lymphoid cells were organized into tertiary lymphoid tissues, hereafter named bladder tertiary lymphoid tissue (bTLT). Analogous bTLTs were found in older women, many of whom had a history of recurrent urinary tract infection (UTI). Aged mice responded poorly to experimental UTI, experiencing spontaneous recurrences at higher rates than young mice. However, bTLT formation was dependent on aging and independent of infection. Furthermore, bTLTs in aged mice played a role in de novo antibody responses and urinary IgA production by recruitment of naive B cells that form germinal centers and mature into IgA-secreting plasma cells. Finally, TNFα was a key driver of bTLT formation, as aged TNFα-/- mice lacked bTLTs. Both aged TNFα-/- and wild type mice exhibited increased bladder permeability, suggesting that epithelial dysfunction may be an upstream mediator of chronic, age-associated bladder inflammation. Thus, bTLTs arise as a function of age and may underlie chronic, age-associated bladder inflammation. Our model establishes a platform for further investigation of age-association tissue inflammation and translation to new treatment strategies.One Sentence SummaryMice develop bladder tertiary lymphoid tissue (bTLT) during aging that is dependent on TNFα and independent of urinary tract infection.

C-Phycocyanin Alleviates Bladder Inflammation and Dysfunction in Cyclophosphamide-Induced Cystitis in a Mouse Model by Inhibiting COX-2 and EP4

Objective. To explore the effect of C-phycocyanin (C-PC) on voiding behavior and histological changes in cyclophosphamide- (CYP-) induced cystitis in mice. Methods. Sixty female mice were included. The mice in the C-PC group received C-PC (25 mg/kg, twice, i.p.) and then CYP (200 mg/kg, i.p.) two hours later, while the mice in the CYP group only received the equivalent CYP. Saline was injected in the mice in the control group. A voided stain on paper (VSOP) test was conducted to analyze the micturition. The bladders were harvested for histological evaluation and measurements of inflammatory factors. Results. C-PC reduced the micturition frequency in the mice with CYP-induced cystitis. The bladder/body weight ratio and edema were remarkably higher in the CYP group compared to the C-PC group. C-PC suppressed the expressions of COX-2, PGE2, and EP4 (prostaglandin E receptor 4) according to the ELISA assay. Immunohistochemical staining also indicated that C-PC reduced the expressions of COX-2 in urothelium and EP4 in smooth muscles. Conclusions. C-PC relieved symptoms associated with CYP-induced cystitis in mice by inhibiting bladder inflammation through COX-2 and EP4 expression.