Genitourinary mast cells and survival

Neutrophil-to-lymphocyte ratio as a promising non-invasive biomarker for symptom assessment and diagnosis of interstitial cystitis/bladder pain syndrome

BACKGROUND

Our study aims to investigate the association between the serum neutrophil-to-lymphocyte ratio (NLR) and interstitial cystitis (IC), as well as to explore whether NLR can serve as a diagnostic marker to distinguish IC from overactive bladder (OAB). We postulate that elevated NLR levels are intricately linked to the onset and clinical presentation of IC, and that the NLR profiles in OAB patients exhibit discernible disparities from those of IC patients.

METHODS

In a retrospective analysis, we scrutinized the medical records of 70 women diagnosed with IC/BPS, 20 women diagnosed with OAB, and a randomly selected cohort of 150 healthy women who underwent physical examinations during the same temporal frame. A comprehensive panel of blood tests was administered to all participants, and NLR was determined through the calculation of the neutrophil-to-lymphocyte proportion. Additionally, symptom assessment questionnaires and urination diaries were collected from IC/BPS patients.

RESULTS

NLR levels exhibited significant distinctions among the IC/BPS, Normal, and OAB groups (P < 0.001). Within the IC/BPS group, Hunner type interstitial cystitis (HIC) demonstrated notably divergent NLR levels in comparison to non-Hunner type interstitial cystitis (NHIC) (p = 0.001). Additionally, we observed positive correlations between NLR and Nighttime voids (r = 0.268, p = 0.029), ICPI (r = 0.327, p = 0.007), ICSI (r = 0.369, p = 0.002), PUF Symptom Scale (r = 0.263, p = 0.032), and PUF (r = 0.297, p = 0.015). The receiver operating characteristic (ROC) analysis yielded an area under the curve (AUC) of 0.765 for NLR in distinguishing IC/BPS from the Normal group, and an AUC of 0.707 in discerning IC from OAB. Furthermore, the AUC of NLR was 0.723 for identifying HIC and NHIC patients.

CONCLUSIONS

Our study unveils the prospective utility of serum NLR as a promising biomarker for both diagnostic and symptom evaluation purposes in IC/BPS patients. It effectively demarcates this condition from OAB, which presents with similar clinical features. Consequently, NLR demonstrates potential as a non-invasive diagnostic instrument to distinguish between the subtypes of IC, particularly HIC and NHIC, which manifest similar symptoms within the IC/BPS spectrum.

Involvement of a neutrophil-mast cell axis in the effects of Piper malacophyllum (C. PESL) C. DC extract and its isolated compounds in a mouse model of dysmenorrhoea

The effects of Piper malacophyllum (C. Pesl) C. DC extracts and its isolated compounds were analysed in a mouse model of primary dysmenorrhoea (PD). Female Swiss mice (6-8 weeks old) on proestrus were intraperitoneally treated with estradiol benzoate for 3 days, to induce PD. Twenty-four hours later, animals were treated 24 h later with vehicle, plant extract, gibbilimbol B, 4,6-dimethoxy-5-E-phenylbutenolide, mixture of 4,6-dimethoxy-5-E-phenylbutenolide and 4,6-dimethoxy-5-Z-phenylbutenolide, or ibuprofen. One hour later, oxytocin was injected and the numbers of abdominal writhing were counted. Then, mice were euthanized and uteri were collected for morphometrical and histological analyses. The effects of P. malacophyllum in inflammation were investigated in mouse peritoneal neutrophils culture stimulated with LPS or fMLP (chemotaxis and mediator release). Finally, uterus contractile and relaxing responses were assessed. Similar to ibuprofen, P. malacophyllum extract and isolated compounds reduced abdominal writhing in mice with PD. Histology indicated a marked neutrophil and mast cell infiltrate in the uterus of PD animals which was attenuated by the extract. The compounds and the extract reduced neutrophil chemotaxis and inflammatory mediator release by these cells. Reduced TNF levels were also observed in uteri of PD mice treated with P. malacophyllum. The extract did not affect spontaneous uterine contractions nor those induced by carbachol or KCl. However, it caused relaxation of oxytocin-induced uterine contraction, an effect blunted by H1 receptor antagonist. Overall the results indicate that P. malacophyllum may represent interesting natural tools for reliving PD symptoms, reducing the triad of pain, inflammation and spasmodic uterus behaviour.

Role of NLRP3 inflammasome in the development of bladder pain syndrome interstitial cystitis

Although it has been proposed that NOD-like receptor protein 3 (NLRP3) inflammasome activation may have an important contribution to the onset of bladder pain syndrome/interstitial cystitis (BPS/IC), as of today there is still insufficient evidence to accept or to reject this hypothesis. However, taking into consideration that inflammasomes have been already shown as important mediators of cyclophosphamide-induced bladder inflammation and that some studies have also revealed human bladder epithelium expresses high levels of NLRP3, such a hypothesis seems to be reasonable. The purpose of this review is to discuss a scenario that NLRP3 inflammasome is a crucial player in the development of this disease. Identification of a novel mediator of bladder inflammation and pain could lead to emerging new therapeutic strategy and the first causative therapy.

Mast cell chymase decreases the severity of group B Streptococcus infections

BACKGROUND

Group B Streptococcus (GBS) or Streptococcus agalactiae are β-hemolytic gram-positive bacteria that colonize the lower genital tracts of women and are frequently associated with infections during pregnancy. Innate immune defenses are critical for controlling GBS dissemination and systemic infection. Mast cells are resident sentinel cells that come into contact with pathogens early during colonization and infection.

OBJECTIVE

We aimed to investigate the contribution of chymase to systemic GBS infection and rates of preterm birth.

METHODS

Pharmacologic and genetic approaches using mice deficient in mast cell protease (MCPT) 4, the mouse functional homologue of human chymase, were used.

RESULTS

Our studies show that mast cells release a protease with chymotrypsin-like cleavage specificity in response to GBS. Additionally, increased GBS systemic infection and preterm births were observed in MCPT4-deficient mice versus MCPT4-sufficient mice. Furthermore, we observed that proteolytic cleavage of the host extracellular matrix protein fibronectin by peritoneal cell-derived mast cell lysates diminished GBS adherence. Consistent with this observation, the increase in GBS dissemination and preterm births observed in MCPT4-deficient mice was abolished when GBS was deficient in expression of the fibronectin-binding protein SfbA.

CONCLUSIONS

Taken together, our results suggest that the protective effect of MCPT4 against GBS dissemination and preterm labor can be attributed in part to MCPT4-mediated proteolysis of fibronectin. Our studies reveal a novel role of mast cells in defense against bacterial infections.

Exploiting a novel conformational switch to control innate immunity mediated by complement protein C3a

Complement C3a is an important protein in innate and adaptive immunity, but its specific roles in vivo remain uncertain because C3a degrades rapidly to form the C3a-desArg protein, which does not bind to the C3a receptor and is indistinguishable from C3a using antibodies. Here we develop the most potent, stable and highly selective small molecule modulators of C3a receptor, using a heterocyclic hinge to switch between agonist and antagonist ligand conformations. This enables characterization of C3 areceptor-selective pro- vs. anti-inflammatory actions in human mast cells and macrophages, and in rats. A C3a receptor-selective agonist induces acute rat paw inflammation by first degranulating mast cells before activating macrophages and neutrophils. An orally administered C3a receptor-selective antagonist inhibits mast cell degranulation, thereby blocking recruitment and activation of macrophages and neutrophils, expression of inflammatory mediators and inflammation in a rat paw edema model. These novel tools reveal the mechanism of C3a-induced inflammation and provide new insights to complement-based medicines.

Complement C3a is an important protein in innate and adaptive immunity, but its roles in vivo are unclear. Here the authors develop novel chemical agonists and antagonists for the C3a receptor, and show that they modulate mast cell degranulation and inflammation in a rat paw edema model