[Changes and clinical significance of NLRP3 inflammasomes and related factors in patients with spinal fracture complicated with acute spinal cord injury].

OBJECTIVE: To investigate the changes and clinical significance of NOD like receptor protein 3 (NLRP3) inflammasomes and related factors in patients with spinal fractures complicated with acute spinal cord injury (SCI). METHODS: Eighty-six spinal fracture patients complicated with acute SCI admitted to hospital from June 2019 to March 2022 were selected as SCI group, There were 48 males and 38 females, with an average age of (43.48±6.58) years old. And 100 healthy volunteers who underwent physical examination during the same time were selected as control group, including 56 males patients and 44 females patients, with an average age of (45.13±6.43) years old. Peripheral blood mononuclear cell (PBMC) were collected, and the mRNA expressions of NLRP3 and Caspase-1 were detected. Serum was collected and the levels of interleukin (IL)- 1ß, IL-18 were detected. According to Frankel's grade, the SCI group was divided into complete injury patients and incomplete injury patients, and according to the Japanese Orthopedic Society (JOA) grade, the SCI group was divided into good prognosis group and poor prognosis group. The difference of NLRP3, Caspase-1, IL-1ß, IL-18 among groups were compared, the influencing factors for poor prognosis in SCI patients was analyzed by Logistic regression. RESULTS: The mRNA expression levels of NLRP3 (1.41±0.33) and Caspase-1 (1.44±0.35) in PBMC and the levels of IL-1ß(45.34±13.22) pg·ml-1, IL-18(40.95±8.77) pg·ml-1 in serum of SCI group were higher than those of the control group[(1.00±0.19), (1.00±0.16), (16.58±4.24) pg·ml-1, (12.57±3.68) pg·ml-1] (P<0.05). The mRNA expression levels of NLRP3(1.63±0.34) and Caspase-1 (1.67±0.27) in PBMC and the levels of IL-1ß(51.09±11.10) pg·ml-1, IL-18 (47.65±7.93) pg·ml-1 in serum of patients with complete injury in the SCI group were higher than those of patients with incomplete injury [(1.31±0.27), (1.34±0.33), (42.85±13.36) pg·ml-1, (38.05±7.48) pg·ml-1](P<0.05). The mRNA expression levels of NLRP3 (1.66±0.31) and Caspase-1 (1.72±0.31)in PBMC and the levels of IL-1ß(51.21±11.31) pg·ml-1, IL-18 (45.70±7.25) pg·ml-1 in serum, the proportion of complete injury(21 patients), and the proportion of spinal cord edema or bleeding of patients(15 patients) with poor prognosis in the SCI group were higher than those of patients with good prognosis[(1.28±0.26), (1.37±0.36), (42.79±13.25) pg·ml-1、(38.90±8.63) pg·ml-1, 5、20 cases](P<0.05). Complete injury and the mRNA expression of NLRP3 in PBMC were the influencing factors for poor prognosis in the SCI group (P<0.05). CONCLUSION: The activation of NLRP3 inflammasomes in patients with spinal fractures complicated with acute SCI is associated with worsening injury and poor prognosis, and NLRP3 expression can serve as a marker for evaluating prognosis.

Brief Pain Inventory (BPI) Pain Survey Versus Cysteine Protease Caspase-1 (Casp1) Blood Levels Following Midline Laparotomy: A Prospective Randomized Study of Patients With Benign Disease and Patients With Cancer.

BACKGROUND/AIM: There is lack of studies assessing the correlation between pain scales and acute phase immune response (APR) following surgery. The purpose of this work was to assess the correlation between cysteine protease caspase-1 (Casp1) blood levels and two pain scales in a cohort of 56 midline laparotomy (MLa) patients and to assess their link with other cytokines (CYTs). PATIENTS AND METHODS: Blood levels of Casp1 and other CYTs (IL-18, IL-18BP, IL-1ra, IL-6, IL-8, IL-10, IL-1ß) were measured before operation and following surgery in patients with MLa. Pain levels were assessed using the Numerical Rating Scale (NRS) and Brief Pain Inventory (BPI) scale, both preoperatively and postoperatively. RESULTS: Casp1 blood levels showed an increasing trend at postoperative day 1 (POP1) and this increase was almost significant in a linear mixed effect model (LME) analysis (p=0.06). Additionally, Casp1 blood levels were higher in patients with cancer than those with benign disease and correlated with IL-18 blood levels (r=0.24, p=0.007). Furthermore, Casp1 blood levels correlated with BPIsev (severity) score values in MLa patients (r=-0.49, p=0.048). A significant correlation was also observed between Casp1 blood levels and NRS scores in patients with MLa. CONCLUSION: This is the first report to evaluate two pain surveys (NRS and BPI) in MLa patients in relation to blood levels of Casp1 and eight CYTs. This analysis is important in confirming the significant correlation between NRS and BPI pain scales and Casp1 blood levels. Our study is also the first to demonstrate that adequate postoperative analgesia in patients with MLa provides better functional ability and improved patient satisfaction.

Increased serum caspase-1 in adult-onset Still's disease.

BACKGROUND: Caspase-1 is a crucial component in the inflammasome activation cascade. This study evaluated the potential of serum caspase-1 level as an inflammatory biomarker in patients with adult-onset Still's disease (AOSD). METHODS: The study included 51 consecutive patients diagnosed with AOSD based on the Yamaguchi criteria, 66 patients with rheumatoid arthritis (RA) as disease control, and 36 healthy controls (HCs). Serum caspase-1 concentrations were measured using enzyme-linked immunosorbent assay. The serum 69 cytokine levels were analyzed using a multisuspension cytokine array in patients with AOSD, and a cluster analysis of each cytokine was performed to determine specific molecular networks. RESULTS: Patients with AOSD had significantly increased serum caspase-1 levels versus patients with RA (p < 0.001) and HCs (p < 0.001). Additionally, serum caspase-1 demonstrated significant positive correlations with AOSD disease activity score (Pouchot score, r = 0.59, p < 0.001) and serum ferritin (r = 0.54, p < 0.001). Furthermore, among patients with AOSD, significant correlations existed between serum caspase-1 and inflammatory cytokines, including interleukin-18. Immunoblot analysis detected the cleaved form of caspase-1 (p20) in the serum of untreated patients with AOSD, not in those from patients with inactive AOSD receiving immunosuppressive treatments. CONCLUSIONS: Caspase-1 is a useful biomarker for AOSD diagnosis and monitoring. Caspase-1 activation could be correlated with the inflammatory component of AOSD, specifically through proinflammatory cytokine induction via inflammasome activation cascades.

Correlation Between Blood Levels of Cysteine Protease Caspase-1 (Casp1) and Pain Scores (NRS) Post-surgery: A Prospective Randomized Study of Patients With Cholelithiasis.

BACKGROUND/AIM: Cysteine protease caspase-1 (Casp1) plays a crucial role in the conversion of pro-cytokines to active cytokines (CYTs). The purpose of this work was to determine Casp1 blood levels in a cohort of 114 cholecystectomy patients and assess their association with other CYTs and numeric rating scale (NRS) pain scores, postoperatively. PATIENTS AND METHODS: Blood levels of Casp1 and seven CYTs (IL-18, IL-18BP, IL-1ra, IL-6, IL-10, IL-1ß, and IL-8) were measured at three time points; before operation, immediately after operation, and six hours after operation in 114 patients with cholelithiasis (Chole). RESULTS: Casp1 blood levels correlated with NRS pain scores at 24 h following surgery (p=0.016). In addition, Casp1 blood levels correlated significantly to IL-18 blood levels (p<0.001). CONCLUSION: This is the first report to evaluate Casp1 blood levels in Chole patients in correlation with other CYTs. The findings confirm a significant correlation between Casp1 blood levels and NRS pain scores. Moreover, this study provides initial evidence suggesting that inhibition of the activity of Casp1 may reduce postsurgical acute phase immune response possibly through the Casp1/pro-Il-18 pathway.

Evaluation of inflammasomes as biomarker following non-surgical periodontal treatment.

OBJECTIVE: The purpose of this study was to investigate interleukin (IL)-1ß, IL-18, nod-like receptor pyrin domain-containing protein 3 (NLRP3), apoptosis-related speck-like protein containing a caspase activation and recruitment domain (ASC), and caspase-1 levels in saliva and serum in different periodontal diseases and to evaluate the changes after non-surgical periodontal treatment (NSPT). DESIGN: A total of 45 participants, 15 healthy, 15 gingivitis, and 15 stage III grade C (SIIIGC) periodontitis patients, were included in the study. Periodontal parameters were assessed, and salivary and serum samples were collected at baseline in all groups and one and three months after NSPT in gingivitis and periodontitis groups. An enzyme-linked immunosorbent assay was used to analyse IL-1ß, IL-18, NLRP3, ASC, and caspase-1 levels. RESULTS: After NSPT, improvement was observed in all clinical parameters, along with periodontal inflamed surface area (PISA) in gingivitis and periodontitis groups. PISA scores were positively correlated with IL-1ß, NLRP3, and caspase-1 at baseline (p < 0.05). Salivary and serum IL-1ß, NLRP3 levels were higher in periodontitis compared to healthy controls at baseline and reduced after treatment (p < 0.05). Receiver operating characteristic analysis revealed that salivary IL-1ß, NLRP3, and caspase-1 had the ability to discriminate SIIIGC periodontitis patients from healthy subjects (p < 0.05). CONCLUSION: In conclusion, salivary IL-1ß, NLRP3, and caspase-1 are at aberrantly high levels in SIIIGC periodontitis and are remarkably decreased following NSPT; these inflammasome biomarkers may show potential utility in diagnosing and monitoring periodontitis.

Caspase-1 and interleukin-18 in children with post infectious bronchiolitis obliterans: a case-control study.

The exact immunological mechanisms of post infectious bronchiolitis obliterans (PIBO) in childhood are not fully known. It has been shown that the inflammasome and IL-18 pathway play important roles in the pathogenesis of lung fibrosis. We aimed to investigate the role of caspase-1, IL-18, and IL-18 components in PIBO. From January to May 2020, children with PIBO, children with history of influenza infection without PIBO, and healthy children were asked to participate in the study in three pediatric pulmonology centers. Serum caspase-1, IL-18, IL-18BP, IL-18R, and INF-γ levels were measured by ELISA and compared between the 3 groups. There were 21 children in the PIBO group, 16 children in the influenza group, and 39 children in the healthy control group. No differences in terms of age and gender between the 3 groups were found. IL-18 and IL-18BP levels were higher in the healthy control group (p = 0.018, p = 0.005, respectively). IL-18R was higher in the PIBO group (p = 0.001) and caspase-1 was higher in the PIBO and influenza group than the healthy control group (p = 0.002). IFN-γ levels did not differ between the 3 groups. IL-18BP/IL-18 was higher in the influenza group than the PIBO group and the healthy control group (p = 0.003). CONCLUSIONS: Caspase-1 level was increased in patients with PIBO which suggests that inflammasome activation may have a role in fibrosis; however, IL-18 level was found to be low. Mediators other than IL-18 may be involved in the inflammatory pathway in PIBO. Further immunological studies investigating inflammasome pathway are needed for PIBO with chronic inflammation. WHAT IS KNOWN: • Post infectious bronchiolitis obliterans (PIBO) is a rare, severe chronic lung disease during childhood which is associated with inflammation and fibrosis which lead to partial or complete luminal obstruction especially in small airways. • The exact immunological mechanisms of PIBO in childhood are not fully known. WHAT IS NEW: • Inflammasome activation persists even years after acute infection and may play a role in fibrosis in PIBO. • Mediators other than IL-18 may be involved in these inflammatory pathway.

Circulating extracellular vesicles activate the pyroptosis pathway in the brain following ventilation-induced lung injury.

BACKGROUND: Mechanical ventilation of preterm newborns causes lung injury and is associated with poor neurodevelopmental outcomes. However, the mechanistic links between ventilation-induced lung injury (VILI) and brain injury is not well defined. Since circulating extracellular vesicles (EVs) are known to link distant organs by transferring their cargos, we hypothesized that EVs mediate inflammatory brain injury associated with VILI. METHODS: Neonatal rats were mechanically ventilated with low (10 mL/kg) or high (25 mL/kg) tidal volume for 1 h on post-natal day 7 followed by recovery for 2 weeks. Exosomes were isolated from the plasma of these rats and adoptively transferred into normal newborn rats. We assessed the effect of mechanical ventilation or exosome transfer on brain inflammation and activation of the pyroptosis pathway by western blot and histology. RESULTS: Injurious mechanical ventilation induced similar markers of inflammation and pyroptosis, such as increased IL-1ß and activated caspase-1/gasdermin D (GSDMD) in both lung and brain, in addition to inducing microglial activation and cell death in the brain. Isolated EVs were enriched for the exosomal markers CD9 and CD81, suggesting enrichment for exosomes. EVs isolated from neonatal rats with VILI had increased caspase-1 but not GSDMD. Adoptive transfer of these EVs led to neuroinflammation with microglial activation and activation of caspase-1 and GSDMD in the brain similar to that observed in neonatal rats that were mechanically ventilated. CONCLUSIONS: These findings suggest that circulating EVs can contribute to the brain injury and poor neurodevelopmental outcomes in preterm infants with VILI through activation of GSDMD.

Characterizing the NLRP3 Inflammasome in Mood Disorders: Overview, Technical Development, and Measures of Peripheral Activation in Adolescent Patients.

The NOD-, LRR-, and pyrin-domain-containing protein 3 (NLRP3) inflammasome is a node of intracellular stress pathways and a druggable target which integrates mitochondrial stress and inflammatory cascades. While a body of evidence suggests the involvement of the NLRP3 inflammasome in numerous diseases, a lack of reliable measurement techniques highlights the need for a robust assay using small quantities of biological samples. We present a literature overview on peripheral activation of the NLRP3 inflammasome in mood disorders, then outline a process to develop and validate a robust assay to measure baseline and activated intracellular levels of "apoptosis-associated speck-like protein containing a CARD" (ASC) as a key component of an inflammatory profile in peripheral blood mononuclear cells (PBMC). A consistent association between high NLRP3 mRNA levels and relevant cytokines was seen in the literature. Using our method to measure ASC, stimulation of PBMC with lipopolysaccharide and nigericin or adenosine triphosphate resulted in microscopic identification of intracellular ASC specks, as well as interleukin 1 (IL-1) beta and caspase-1 p10 in the periphery. This was abolished by dose-dependent pre-treatment with 100 nM MCC950. We also report the use of this technique in a small pilot sample from patients with bipolar disorder and depressive disorders. The results show that levels of intracellular ASC and IL-1 beta are sensitive to change upon activation and maintained over time, which may be used to improve the detection of NLRP3 activation and guide personalized therapeutic strategy in the treatment of patients.

Inflammasome Activation in Children With Kawasaki Disease and Multisystem Inflammatory Syndrome.

[Figure: see text].

The Inflammasome Signaling Pathway Is Actively Regulated and Related to Myocardial Damage in Coronary Thrombi from Patients with STEMI.

BACKGROUND: The Nod-Like-Receptor-Protein-3 (NLRP3) inflammasome and the Interleukin-6 (IL-6) pathways are central mechanisms of the inflammatory response in myocardial reperfusion injury. Expanding our knowledge about the inflammasome signaling axis is important to improve treatment options. In a cross-sectional study, we aimed to study presence, localization, and genetic expression of inflammasome- and IL-6- signaling-related proteins in coronary thrombi and circulating leukocytes from ST-elevation myocardial infarction (STEMI) patients, with relation to myocardial injury and time from symptoms to PCI. METHODS: Intracoronary thrombi were aspirated from 33 STEMI patients. Blood samples were drawn. mRNA of Toll-Like-Receptor-4 (TLR4), NLRP3, caspase 1, Interleukin-1ß (IL1-ß), Interleukin-18 (IL-18), IL-6, IL-6-receptor (IL-6R), and glycoprotein 130 (gp130) were isolated from thrombi and circulating leukocytes and relatively quantified by RT-PCR. A part of each thrombus was embedded in paraffin for histology and immunohistochemistry analyses. RESULTS: Genes encoding the 8 markers were present in 76-100% of thrombi. Expression of TLR4 in thrombi significantly correlated to troponin T (r = 0.455, p = 0.013), as did NLRP3 (r = 0.468, p = 0.024). Troponin T correlated with expression in circulating leukocytes of TLR4 (r = 0.438, p = 0.011), NLRP3 (r = 0.420, p = 0.0149), and IL-1ß (r = 0.394, p = 0.023). IL-6R expression in thrombi correlated significantly to troponin T (r = 0.434, p = 0.019), whereas gp130 was inversely correlated (r = -0.398, p = 0.050). IL-6 in circulating leukocytes correlated inversely to troponin T (r = -0.421, p = 0.015). There were no significant correlations between genes expressed in thrombi and time from symptom to PCI. CONCLUSIONS: The inflammasome signaling pathway was actively regulated in coronary thrombi and in circulating leukocytes from patients with STEMI, in association with myocardial damage measured by troponin T. This supports the strategy of medically targeting this pathway in treating myocardial infarction and contributes to sort out optimal timing and targets for anti-inflammatory treatment. The study is registered at clinicaltrials.gov with identification number NCT02746822.

Effects of regular exercise on inflammasome activation-related inflammatory cytokine levels in older adults: a systematic review and meta-analysis.

Exercise has been found to play important roles in regulating inflammation, although the mechanisms are unclear. The present systematic review and meta-analysis aimed to investigate whether regular exercise could regulate inflammation through inflammasome activation signalling in older adults. Five databases were searched, and 19 randomised controlled trials (RCTs) studying effects of regular exercise on inflammasome activation-related inflammatory cytokines interleukin (IL)-1ß and IL-18 and other key molecules involved in inflammasome activation signalling such as NOD-like receptor family pyrin domain containing 3 (NLRP3), apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), caspase-1 in older adults aged 50 years or older were included. The results showed that regular exercise could significantly decrease the levels of IL-1ß and IL-18, important end-products of inflammasome activation in older adults. Subgroup analyses showed that aerobic exercise is the most effective training modality, and low-to-moderate intensity and mixed intensity are better compared with high intensity to decrease IL-1ß and IL-18. The effect of regular exercise on key molecules involved in inflammasome activation signalling including NLRP3, ASC and caspase-1 is understudied and needs to be further investigated. These findings demonstrate that regular exercise could effectively decrease inflammasome activation-related inflammatory cytokine levels in older adults.

Lipopolysaccharide stimulation test on cultured PBMCs assists the discrimination of cryopyrin-associated periodic syndrome from systemic juvenile idiopathic arthritis.

Systemic juvenile idiopathic arthritis (sJIA) and cryopyrin-associated periodic syndrome (CAPS) share many common manifestations. We aim to identify an applicable method to assist disease discrimination. Inflammatory cytokines were measured in the plasma of patients with CAPS, sJIA with persistent disease course and healthy controls. Supernatants collected from non-stimulated peripheral blood mononuclear cells (PBMCs) and those undergone inflammasome stimulation tests utilizing lipopolysaccharide (LPS) with and without adenosine triphosphate (ATP) were investigated. Inflammatory cytokines in patient plasma fail to differentiate sJIA from CAPS. PBMCs from sJIA secrets higher amount of IL-1ß and IL-18 while CAPS PBMCs produces more caspase-1 without stimulation. IL-1ß, IL-18, and caspase-1 were significantly elevated among CAPS PBMCs (all p < 0.05) upon LPS stimulation, but not when additional ATPs were provided. Levels of cytokines and PBMC responses to the stimulation assays were similar among all sJIA patients regardless of their history of macrophage activation syndrome. Unstimulated PBMC activities and the LPS inflammasome stimulation assay without exogenic ATPs can assist the differentiation of CAPS from sJIA with persistent disease course.

Gene-Dose Effect of MEFV Gain-of-Function Mutations Determines ex vivo Neutrophil Activation in Familial Mediterranean Fever.

Familial Mediterranean fever (FMF) is caused by mutations within the Mediterranean fever (MEFV) gene. Disease severity depends on genotype and gene dose with most serious clinical courses observed in patients with M694V homozygosity. Neutrophils are thought to play an important role in the initiation and perpetuation of inflammatory processes in FMF, but little is known about the specific characteristics of these cells in FMF patients. To further characterize neutrophilic inflammatory responses in FMF and to delineate gene-dose effects on a cellular level, we analyzed cytokine production and activation levels of isolated neutrophils derived from patients and subjects with distinct MEFV genotypes, as well as healthy and disease controls. Serum levels of interleukin-18 (IL-18) (median 11,485 pg/ml), S100A12 (median 9,726 ng/ml), and caspase-1 (median 394 pg/ml) were significantly increased in patients with homozygous M694V mutations. Spontaneous release of S100A12, caspase-1, proteinase 3, and myeloperoxidase (MPO) was restricted to ex vivo cultured neutrophils derived from patients with two pathogenic MEFV mutations. IL-18 secretion was highest in patients with two mutations but also increased in neutrophils from healthy heterozygous MEFV mutation carriers, exhibiting an ex vivo gene-dose effect, which was formerly described by us in patients' serum. CD62L (l-selectin) was spontaneously shed from the surface of ex vivo cultured neutrophils [median of geometric mean fluorescence intensity (gMFI) after 5 h: 28.8% of the initial level]. While neutrophils derived from healthy heterozygous mutation carriers again showed a gene-dose effect (median gMFI: 67.1%), healthy and disease controls had significant lower shedding rates (median gMFI: 83.6 and 82.9%, respectively). Co-culture with colchicine and/or stimulation with adenosine triphosphate (ATP) and lipopolysaccharide (LPS) led to a significant increase in receptor shedding. Neutrophils were not prevented from spontaneous shedding by blocking IL-1 or the NLRP3 inflammasome. In summary, the data demonstrate that ex vivo cultured neutrophils derived from FMF patients display a unique phenotype with spontaneous release of high amounts of IL-18, S100A12, MPO, caspase-1, and proteinase 3 and spontaneous activation as demonstrated by the loss of CD62L. Neutrophilic activation seems to be independent from IL-1 activation and displays a gene-dose effect that may be responsible for genotype-dependent phenotypes.

Systemic juvenile idiopathic arthritis and recurrent macrophage activation syndrome due to a CASP1 variant causing inflammasome hyperactivation.

OBJECTIVES: We investigated a patient with systemic juvenile idiopathic arthritis (sJIA) and recurrent macrophage activation syndrome (MAS) to discover genetic and immunological contributing factors. METHODS: Severe recurrent MAS motivated whole exome sequencing (WES) to identify genetic variants potentially involved in disease pathogenesis. In vitro peripheral blood mononuclear cell (PBMC) stimulations for cytokine expression and caspase-1 activity assays as well as NF-κB reporter luciferase assays were performed to functionally characterize variants. RESULTS: WES revealed an extremely rare heterozygous missense variant, c.482G>A, p.R161H in the CASP1 gene encoding pro-caspase-1. Lipopolysaccharide (LPS) stimulation of patient PBMCs induced high levels of IL-6 compared to controls, and activation of the NLRP3 inflammasome resulted in increased production of IL-1ß and IL-18 as well as significantly elevated caspase-1 activity. Constitutive and inducible levels of IL-18 and IFNγ in whole blood were markedly elevated. Expression of the CASP1 variant in an NF-κB reporter luciferase assay induced increased NF-κB activation in a RIP2-dependent manner. The disease course of the patient was complicated by severe recurrent MAS. However, dual IL-1 and IL-6 blockade caused disease remission. CONCLUSION: For the first time, we demonstrate the involvement of a CASP1 variant in sJIA and recurrent MAS. This variant is gain-of-function for both inflammasome and NF-κB activation leading to increased production of IL-6, IL-1ß and IL-18. Although dual IL-1 and IL-6 blockade may be beneficial in patients, in whom single treatment is not sufficient to control MAS, caution should be practiced, since interstitial lung disease may progress despite apparent clinical and biochemical remission.

Quartz Dust Exposure Affects NLRP3 Inflammasome Activation and Plasma Levels of IL-18 and IL-1Ra in Iron Foundry Workers.

PURPOSE: To study the association between inhalation of particulate matter or quartz in Swedish iron foundries and the effects on NLRP3 inflammasome activation. METHODS: Particle exposure measurements were performed during an eight-hour work day for 85 foundry workers at three Swedish iron foundries. Personal sampling was used for measurement of respirable quartz and dust and stationary measurements to obtain exposure measurements for inhalable dust and PM10. The NLRP3 inflammasome markers, interleukin- (IL-) 1ß and IL-18, and inhibitors IL-1 receptor antagonist (IL-1Ra) and IL-18 binding protein (IL-18BP) were measured in plasma. Inflammasome activation was measured by caspase-1 enzymatic activity in monocytes in whole blood by flow cytometry, and expression of inflammasome-related genes was quantified using real-time PCR. Multiple linear regression analysis was used to investigate associations between PM exposures and inflammatory markers. Sex, age, smoking, current infection, BMI, and single nucleotide polymorphism in the inflammasome regulating genes CARD8 (C10X) and NLRP3 (Q705K) were included as covariates. RESULTS: The average exposure levels of respirable dust and quartz were 0.85 and 0.052 mg/m3, respectively. A significant exposure-response was found for respirable dust and IL-18 and for inhalable dust and IL-1Ra. Whole blood, drawn from study participants, was stimulated ex vivo with inflammasome priming stimuli LPS or Pam3CSK4, resulting in a 47% and 49% increase in caspase-1 enzymatic activity in monocytes. This increase in caspase-1 activity was significantly attenuated in the higher exposure groups for most PM exposure measures. CONCLUSIONS: The results indicate that exposure levels of PM in the iron foundry environment can affect the NLRP3 inflammasome and systemic inflammation.

Caspase-1-Dependent Pyroptosis of Peripheral Blood Mononuclear Cells Is Associated with the Severity and Mortality of Septic Patients.

PURPOSE: Pyroptosis has been known to play a vital role in the inflammation process which was induced by infection, injury, or inflammatory disease. The present study was aimed at evaluating the percentage of peripheral blood mononuclear cell (PBMC) pyroptosis in septic patients and assessing the correlation of PBMC pyroptosis with the severity and the mortality of septic patients. METHODS: 128 trauma-induced patients with sepsis were enrolled in this prospective cohort study. Blood samples were collected, and PBMC pyroptosis was measured by flow cytometry within 24 hours after sepsis was diagnosed. RESULTS: Percentage of PBMC pyroptosis was positively correlated with the acute physiology and chronic health evaluation (APACHE) II score and sequential organ failure assessment (SOFA) score (all P < 0.01). The area under the curve (AUC) for the percentage of PBMC pyroptosis on a receiver operating characteristic curve was 0.79 (95% confidence interval (CI), 0.68-0.90). A Cox proportional hazard model identified an association between an increased percentage of PBMC pyroptosis (>14.17%) and increased risk of the 28-day mortality (hazard ratio = 1.234, 95% CI, 1.014-1.502). CONCLUSION: The percentage of PBMC pyroptosis increases in septic patients, and the increased percentage of PBMC pyroptosis is associated with the severity of sepsis and the 28-day mortality of patients with sepsis.

Serum Caspase-1 levels in women with polycystic ovary syndrome.

OBJECTIVE: Caspase-1 is implicated in several important inflammatory diseases and controls adipocyte differentiation and insulin sensitivity. Interleukin-10 (IL-10) is an anti-inflammatory cytokine and plays an important role in chronic inflammatory conditions. This study was planned to determine if there is any relationship between Caspase-1 and IL-10 levels in women with PCOS. MATERIALS AND METHODS: Forty-two women with PCOS and thirty-seven healthy controls were evaluated in this controlled clinical study. Caspase-1 and IL-10 levels, serum lipid sub-fractions, fasting glucose, fasting insulin and other hormones (gonadotropins, androgens), malondialdehyde (MDA) and glutathione (GSH) levels were measured. Homeostasis model assessment (HOMA-IR) was used to estimate insulin resistance. RESULTS: Free androgen index (FAI), HOMA-IR, MDA and Caspase-1 levels were significantly higher in subjects with PCOS. However, the women with PCOS had considerably lower GSH concentration levels than healthy subjects. Serum IL-10 levels were higher in study subjects than in controls, though it was statistically insignificant. Caspase-1 was positively associated with IL-10. CONCLUSION: These outcomes propose that Caspase-1 may have a role in triggering the processes leading to chronic low-grade inflammation in women with PCOS, independent of insulin resistance, androgen excess and oxidative stress. Nevertheless, the precise role of Caspase-1 in the pathogenesis of the disease remains to be elucidated.

Paeonol ameliorates murine alcohol liver disease via mycobiota-mediated Dectin-1/IL-1ß signaling pathway.

Alcoholic liver disease (ALD) is caused by long-term consumption of alcohol and has become an important social and medical problem. Intestinal fungal flora (mycobiota) play an important role in ALD, so we used the mycobiota as an entry point to explore the mechanism of action of Paeonol against ALD. Here, we found that Paeonol is effective against ALD inflammatory lesions and relieves liver fat lesions. Furthermore, we found that after the treatment of Paeonol, the fungal dysbiosis is improved, and the fungal abundance is reduced, and the translocation of ß-glucan to the liver and its mediated Dectin-1/IL-1ß signaling pathway is blocked. Our study shows that paeonol ameliorated acute ALD-related inflammatory injury to the liver by alleviating intestinal fungal dysbiosis and inhibiting the mycobiota-mediated Dectin-1/IL-1ß signaling pathway.

Lipoxin A4 suppresses angiotensin II type 1 receptor autoantibody in preeclampsia via modulating caspase-1.

Preeclampsia (PE) remains a leading cause of maternal and neonatal morbidity and mortality. Numerous studies have shown that women with PE develop autoantibody, termed angiotensin II type 1 receptor autoantibody (AT1-AA), and key features of the disease result from it. Emerging evidence has indicated that inflammatory cell necrosis, such as pyroptosis, could lead to autoantigen exposure and stimulate autoantibody production. Caspase-1, the central enzyme of inflammasome and key target of pyroptosis, may play roles in AT1R exposure and AT1-AA production. Exploring endogenous regulator that could inhibit AT1-AA production by targeting pyroptosis will be essential for treating PE. Lipoxin A4 (LXA4), endogenous dual anti-inflammatory and proresolving lipid mediator, may inhibit AT1-AA production via modulating caspase-1. Thus, we explore whether caspase-1 is essential for AT1-AA production and LXA4 inhibits AT1-AA via modulating caspase-1. PE patients and mice developed AT1-AA associated with caspase-1 activation. Caspase-1 deletion leaded to AT1-AA decrease in PE mice. Consistent with these findings, we confirmed caspase-1 activation, trophoblast pyroptosis and AT1R exposure in PE mice and trophoblast model, while caspase-1 deficiency showed decreased trophoblast pyroptosis and AT1R exposure in vitro and in vivo. Interestingly, LXA4 could suppress AT1-AA production via regulating caspase-1 as well as enhancing phagocytosis of dead trophoblasts by macrophages. These results suggest that caspase-1 promotes AT1-AA production via inducing trophoblast pyroptosis and AT1R exposure, while LXA4 suppresses AT1-AA production via modulating caspase-1, supporting caspase-1 serving as a therapeutic target for attenuating AT1-AA and LXA4 protecting patients from AT1-AA and PE.

Increased Level of Caspase-1 in the Serum of Relapsing-remitting Multiple Sclerosis (RRMS) Patients.

Multiple sclerosis (MS) is an inflammatory autoimmune disease of the central nervous system, in which proinflammatory cytokines play a critical role in the pathogenic formation of lesions. Caspase-1 is a cysteine protease that proteolytically cleaves precursors of interleukin (IL)-18 and IL-1ß and turns them into their active forms. These inflammatory cytokines play an important role in the development of MS. The aim of the present study was the investigation of caspase-1 and its downstream products, IL-18 and IL-1ß, in relapsing-remitting MS (RRMS) patients. In this study, we used an ELISA assay to measure serum and cellular caspase-1 and serum levels of IL-18 and IL-1ß in RRMS patients in the relapse phase (n=23) and healthy age-and gender-matched controls (n=19). We observed that the caspase-1 level was significantly increased in the serum of MS patients compared to the healthy controls (p=0.03). Although caspase-1 concentration in the lysate of peripheral blood mononuclear cells (PBMCs) was higher than serum among patients and controls (p<0.001), no significant difference was found in cellular levels of caspase-1 between the two groups. There was no significant difference in serum levels of IL-18 and IL-1ß between patients and controls. In this study, we found an elevation of extracellular caspase-1, as a reflection of its intracellular level, in the serum of RRMS patients during the relapse phase. Therefore, it suggests being a suitable peripheral biomarker of disease activity in multiple sclerosis.