VEXAS syndrome is characterized by inflammasome activation and monocyte dysregulation.

Acquired mutations in the UBA1 gene were recently identified in patients with severe adult-onset auto-inflammatory syndrome called VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic). However, the precise physiological and clinical impact of these mutations remains poorly defined. Here we study a unique prospective cohort of VEXAS patients. We show that monocytes from VEXAS are quantitatively and qualitatively impaired and display features of exhaustion with aberrant expression of chemokine receptors. In peripheral blood from VEXAS patients, we identify an increase in circulating levels of many proinflammatory cytokines, including IL-1ß and IL-18 which reflect inflammasome activation and markers of myeloid cells dysregulation. Gene expression analysis of whole blood confirms these findings and also reveals a significant enrichment of TNF-α and NFκB signaling pathways that can mediate cell death and inflammation. This study suggests that the control of the nflammasome activation and inflammatory cell death could be therapeutic targets in VEXAS syndrome.

Acute heart failure in elderly patients admitted to the emergency department with acute dyspnea: a multimarker approach diagnostic study.

BACKGROUND AND IMPORTANCE: Diagnosing acute heart failure (AHF) is difficult in elderly patients presenting with acute dyspnea to the emergency department. OBJECTIVES: To assess the diagnostic accuracy of NT-proBNP, high-sensitivity cardiac troponin-I (Hs-cTnI), soluble ST2 (ST2), galectin-3 and CD146 alone and in combination for diagnosing AHF in elderly patients presenting with acute dyspnea to the emergency department. DESIGN, SETTINGS AND PARTICIPANTS: This was a prospective, multicenter study performed between September 2016 and January 2020, including elderly patients presenting with acute dyspnea to the emergency department of 6 French hospitals. INTERVENTION: Measurement of NT-proBNP, hs-cTnI, ST2, galectin-3 and CD146. OUTCOME MEASURE AND ANALYSIS: The reference standard, AHF, was adjudicated by two independent physicians based on ED and hospitalization clinical, biological (excluding biomarkers), radiological and echocardiography data (performed by a cardiologist in the cardiology department specifically for this study). Three exploratory methods (two using a cross-sectional approach with logistic regression and counting all biomarker combinations, and one using a sequential approach with gray zone optimizations) were applied to create comprehensive combinations of the 5 biomarkers for measuring diagnostic accuracy. MAIN RESULTS: Two hundred thirty-eight patients (median age of 85 years, IQR = 8) were analyzed, and 110 (46%) were diagnosed with AHF. The accuracies of NT-proBNP, CD146, hs-cTnI, galectin-3, and ST2 were 0.72 [95% confidence interval (CI) 0.66-0.77], 0.63 (95% CI 0.57-0.69), 0.59 (95% CI 0.53-0.65), 0.55 (95% CI 0.49-0.61) and 0.51 (95% CI 0.45-0.57), respectively. Regardless of the approach used or how the 5 biomarkers were combined, the best accuracy for diagnosing AHF (0.73, 95% CI 0.67-0.78) did not differ from that of NT-proBNP alone. CONCLUSION: In this study, NT-proBNP alone exhibited the best diagnostic accuracy for diagnosing AHF in elderly patients presenting with acute dyspnea to the emergency departments. None of the other biomarkers alone or combined improved the accuracy compared to NT-proBNP, which is the only biomarker to use in this setting.

The Antioxidant TEMPOL Protects Human Hematopoietic Stem Cells From Culture-Mediated Loss of Functions.

In a steady state, hematopoietic stem cells (HSC) exhibit very low levels of reactive oxygen species (ROS). Upon stress, HSC get activated and enter into proliferation and differentiation process to ensure blood cell regeneration. Once activated, their levels of ROS increase, as messengers to mediate their proliferation and differentiation programs. However, at the end of the stress episode, ROS levels need to return to normal to avoid HSC exhaustion. It was shown that antioxidants can prevent loss of HSC self-renewal potential in several contexts such as aging or after exposure to low doses of irradiation suggesting that antioxidants can be used to maintain HSC functional properties upon culture-induced stress. Indeed, in humans, HSC are increasingly used for cell and gene therapy approaches, requiring them to be cultured for several days. As expected, we show that a short culture period leads to drastic defects in HSC functional properties. Moreover, a switch of HSC transcriptional program from stemness to differentiation was evidenced in cultured HSC. Interestingly, cultured-HSC treated with 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (4-hydroxy-TEMPO or Tempol) exhibited a higher clonogenic potential in secondary colony forming unit cell (CFU-C) assay and higher reconstitution potential in xenograft model, compared to untreated cultured-HSC. By transcriptomic analyses combined with serial CFU-C assays, we show that Tempol, which mimics superoxide dismutase, protects HSC from culture-induced stress partly through VEGFα signaling. Thus, we demonstrate that adding Tempol leads to the protection of HSC functional properties during ex vivo culture.

RAS activation induces synthetic lethality of MEK inhibition with mitochondrial oxidative metabolism in acute myeloid leukemia.

Despite recent advances in acute myeloid leukemia (AML) molecular characterization and targeted therapies, a majority of AML cases still lack therapeutically actionable targets. In 127 AML cases with unmet therapeutic needs, as defined by the exclusion of ELN favorable cases and of FLT3-ITD mutations, we identified 51 (40%) cases with alterations in RAS pathway genes (RAS+, mostly NF1, NRAS, KRAS, and PTPN11 genes). In 79 homogeneously treated AML patients from this cohort, RAS+ status were associated with higher white blood cell count, higher LDH, and reduced survival. In AML models of oncogenic addiction to RAS-MEK signaling, the MEK inhibitor trametinib demonstrated antileukemic activity in vitro and in vivo. However, the efficacy of trametinib was heterogeneous in ex vivo cultures of primary RAS+ AML patient specimens. From repurposing drug screens in RAS-activated AML cells, we identified pyrvinium pamoate, an anti-helminthic agent efficiently inhibiting the growth of RAS+ primary AML cells ex vivo, preferentially in trametinib-resistant PTPN11- or KRAS-mutated samples. Metabolic and genetic complementarity between trametinib and pyrvinium pamoate translated into anti-AML synergy in vitro. Moreover, this combination inhibited the propagation of RA+ AML cells in vivo in mice, indicating a potential for future clinical development of this strategy in AML.

Impaired type I interferon activity and inflammatory responses in severe COVID-19 patients.

Coronavirus disease 2019 (COVID-19) is characterized by distinct patterns of disease progression that suggest diverse host immune responses. We performed an integrated immune analysis on a cohort of 50 COVID-19 patients with various disease severity. A distinct phenotype was observed in severe and critical patients, consisting of a highly impaired interferon (IFN) type I response (characterized by no IFN-ß and low IFN-α production and activity), which was associated with a persistent blood viral load and an exacerbated inflammatory response. Inflammation was partially driven by the transcriptional factor nuclear factor-κB and characterized by increased tumor necrosis factor-α and interleukin-6 production and signaling. These data suggest that type I IFN deficiency in the blood could be a hallmark of severe COVID-19 and provide a rationale for combined therapeutic approaches.

Procalcitonin and C-Reactive Protein for Bacterial Infection Diagnosis in Elderly Patients After Traumatic Orthopedic Surgery.

BACKGROUND: Biomarkers prove valuable for diagnosing postoperative bacterial infection, but data in elderly patients are scarce. Here we analyze how procalcitonin and C-reactive protein (CRP) perform for bacterial infection diagnosis after traumatic orthopedic surgery in elderly patients. METHODS: We included all patients admitted to our perioperative geriatrics unit after traumatic orthopedic surgery. Patients on antibiotics, presenting preoperative bacterial infection, or without procalcitonin measurement were excluded. Clinical and biological data were collected prospectively. Medical charts were reviewed by three experts blinded to biomarker results to assess bacterial infection diagnosis. Areas under the curve and 90%-specificity thresholds were analyzed for baseline procalcitonin and CRP levels and relative variations. RESULTS: Analysis included 229 patients (median age 86 years, hip fracture 83%), of which 40 had bacterial infection (pneumonia [n = 23], urinary tract infection [n = 8]; median delay to onset: 2 days post-admission). For bacterial infection diagnosis, the computed areas under the curve were not significantly different (procalcitonin-baseline 0.64 [95% confidence interval: 0.57-0.70]; procalcitonin-relative variation 0.65 [0.59-0.71]; CRP-baseline 0.68 [0.61-0.74]; CRP-relative variation 0.70 [0.64-0.76]). The 90%-specificity thresholds were 0.75 µg/L for procalcitonin-baseline, +62% for procalcitonin-variation, 222 mg/L for CRP-baseline, +111% for CRP-variation. CONCLUSIONS: Diagnostic performances of procalcitonin and CRP were not significantly different. Baseline levels and relative variations of these biomarkers showed little diagnostic value after traumatic orthopedic surgery in elderly patients.

Role of thyroid dysimmunity and thyroid hormones in endometriosis.

Endometriosis is characterized by the presence of ectopic endometrial cells outside the uterine cavity. Thyroid autoimmunity has been associated with endometriosis. This work investigated the potential pathophysiological link between endometriosis and thyroid disorders. Transcripts and proteins involved in thyroid metabolism are dysregulated in eutopic and ectopic endometrium of endometriotic patients, leading to resistance of ectopic endometrium to triiodothyronine (T3) action and local accumulation of thyroxine (T4). Thyroid-stimulating hormone (TSH) acts as a proliferative and prooxidative hormone on all endometria of endometriosis patients and controls, whereas T3 and T4 act to specifically increase ectopic endometrial cell proliferation and reactive oxygen species (ROS) production. Mouse studies confirmed the data gained in vitro since endometriotic implants were found to be bigger when thyroid hormones increased. A retrospective analysis of endometriosis patients with or without a thyroid disorder revealed an increased chronic pelvic pain and disease score in endometriotic patients with a thyroid disorder.

Preventive action of benztropine on platinum-induced peripheral neuropathies and tumor growth.

The endogenous cholinergic system plays a key role in neuronal cells, by suppressing neurite outgrowth and myelination and, in some cancer cells, favoring tumor growth. Platinum compounds are widely used as part of first line conventional cancer chemotherapy; their efficacy is however limited by peripheral neuropathy as a major side-effect. In a multiple sclerosis mouse model, benztropine, that also acts as an anti-histamine and a dopamine re-uptake inhibitor, induced the differentiation of oligodendrocytes through M1 and M3 muscarinic receptors and enhanced re-myelination. We have evaluated whether benztropine can increase anti-tumoral efficacy of oxaliplatin, while preventing its neurotoxicity.We showed that benztropine improves acute and chronic clinical symptoms of oxaliplatin-induced peripheral neuropathies in mice. Sensory alterations detected by electrophysiology in oxaliplatin-treated mice were consistent with a decreased nerve conduction velocity and membrane hyperexcitability due to alterations in the density and/or functioning of both sodium and potassium channels, confirmed by action potential analysis from ex-vivo cultures of mouse dorsal root ganglion sensory neurons using whole-cell patch-clamp. These alterations were all prevented by benztropine. In oxaliplatin-treated mice, MBP expression, confocal and electronic microscopy of the sciatic nerves revealed a demyelination and confirmed the alteration of the myelinated axons morphology when compared to animals injected with oxaliplatin plus benztropine. Benztropine also prevented the decrease in neuronal density in the paws of mice injected with oxaliplatin. The neuroprotection conferred by benztropine against chemotherapeutic drugs was associated with a lower expression of inflammatory cytokines and extended to diabetic-induced peripheral neuropathy in mice.Mice receiving benztropine alone presented a lower tumor growth when compared to untreated animals and synergized the anti-tumoral effect of oxaliplatin, a phenomenon explained at least in part by benztropine-induced ROS imbalance in tumor cells.This report shows that blocking muscarinic receptors with benztropine prevents peripheral neuropathies and increases the therapeutic index of oxaliplatin. These results can be rapidly transposable to patients as benztropine is currently indicated in Parkinson's disease in the United States.

Is Endocan a Diagnostic Marker for Pneumonia After Cardiac Surgery? The ENDOLUNG Study.

BACKGROUND: Postoperative pneumonia is frequent after cardiac surgery and is associated with increased morbidity and mortality. We tested the hypothesis that endocan is an early biomarker for the detection of pneumonia after cardiac surgery. METHODS: Between January and May 2016, 155 patients scheduled to undergo elective cardiac surgery with cardiopulmonary bypass were prospectively included in the study. Serum level of endocan was measured at five timepoints (preoperative, and at 6, 24, 48, and 72 hours after the end of surgery). Procalcitonin and C-reactive protein were measured at 24 and 72 hours. The preoperative and postoperative characteristics of the patients were recorded. Independent predictors of postoperative pneumonia were identified by logistic regression. Threshold values of endocan predictive of postoperative pneumonia were determined using receiver-operating characteristics curve analysis. RESULTS: Seventeen patients (11%) had pneumonia after surgery. Endocan greater than 3.7 ng/mL before induction of anesthesia, or greater than 12.1 ng/mL at 6 hours after surgery, as well body mass index higher than 27 kg/m2 and duration of surgery were independent predictors of postoperative pneumonia. At induction of anesthesia, an endocan cutoff value of 3.7 ng/mL had 65% sensitivity and 72% specificity for the prediction of postoperative pneumonia; whereas at 6 hours, with a cutoff value of 12.1 ng/mL, these values were 71% and 75%, respectively. The time saved by endocan dosage compared with clinical diagnosis of postoperative pneumonia was 96 hours. CONCLUSIONS: This study shows that endocan is an early marker of postoperative pneumonia in patients after cardiac surgery.

Endocan is a stable circulating molecule in ICU patients.

BACKGROUND: Endocan is a lung endothelial cell secreted proteoglycan, possessing multiple physiological roles and potential therapeutic and diagnostic utility as biomarker in pneumonia and acute respiratory distress syndrome. Endocan synthesis and secretion can be induced by proinflammatory cytokines such as TNF-α, but can also be subject of proteolytic degradation causing preanalytical variation. METHODS: We investigated the stability of endocan in conventional serum, plasma, anticoagulated whole blood, as well as whole blood and plasma stabilized with protease inhibitors. RESULTS: Among the recipient tubes for blood collection, those with EDTA gave minimal interference. No dilution effect was observed on recovery tests from 1:2 to 1:16 (v:v). The recovery test in 10 plasma EDTA samples from healthy subjects or septic patients indicated a median recovery of 104.5% [104%-107.5%], and 97% [88.5%; 102.5%], respectively. Patient's plasma endocan remains stable when stored at room temperature till 72h, or following 3 freeze thaw cycles. Finally, no interference was observed with hemolytic, icteric or turbidic plasma samples. CONCLUSION: These results are consistent with the view that endocan measured in ICU patients is intact, stable, and accurate. Then, the low endocan level observed in ICU patients who developed ARDS is likely to be reliable.

Prognostic Value of Serum Procalcitonin After Orthopedic Surgery in the Elderly Population.

Background: Orthopedic surgery is more and more frequent in the older patients and is associated with a high mortality rate. Although serum procalcitonin levels are associated with prognosis in young adults, data are still lacking in the elderly population, and especially after surgery. The main objective of this study was to determine the prognostic value of procalcitonin levels in a large geriatric orthopedic population, and we compared it with clinical variables and biomarkers. Methods: This is a prospective study including patients admitted in our dedicated geriatric postoperative unit, after orthopedic surgery with immediate postoperative measured procalcitonin levels. Collected data included age, sex, medical history, functional status (activities of daily living [ADL]), fracture type, Cumulative Illness Rating scale (CIRS), postoperative complications, and biological data. The primary endpoint was the 30-day mortality. Results: 436 patients (age 85±6 years) were included. Hip fracture surgery was the most frequent (n = 310; 71%), and the 30-day mortality rate was 6.9%. Compared with C-reactive protein (CRP), albumin, CIRS, and ADL, procalcitonin had the highest area under the receiver operating characteristic curve for predicting 30-day mortality (0.74; 95% CI: 0.70-0.78). Using a cutoff at 1 µg/L, procalcitonin was more specific than CIRS to predict 30-day mortality (92 vs 77%; p < .001). In a multivariable analysis, procalcitonin level higher than 0.39 µg/L is a significant predictor of mortality within 30 days (odds ratio 3.84; 95% CI: 1.61-9.14, p = .002). Conclusion: Elevated procalcitonin values were strongly and significantly associated with mortality within 30 days in older patients after orthopedic surgery.

Relevance of Endothelial Cell-Specific Molecule 1 (Endocan) Plasma Levels for Predicting Pulmonary Infection after Cardiac Surgery in Chronic Kidney Disease Patients: The Endolung Pilot Study.

OBJECTIVES: This pilot study aimed to evaluate the relevance of endocan plasma levels for predicting pulmonary infection after cardiac surgery in patients with chronic kidney disease (CKD). METHODS: Serum collected in a previous prospective cohort study (from 166 patients with preoperative CKD who underwent cardiac surgery) was used. Five patients with postoperative pulmonary infection were compared with 15 randomly selected CKD patients with an uneventful outcome. Blood samples were tested at 4 time points (preoperatively and 6, 12, and 24 h after the end of surgery). Endocan, procalcitonin, and C-reactive protein plasma levels were compared between the two groups. RESULTS: At 6 h, the patients with pulmonary infection had significantly higher levels of endocan than the patients without pulmonary infection (24.2 ± 15.6 vs. 6.4 ± 3.2 ng/mL; p = 0.03). A receiver operating characteristic curve analysis showed 80% sensitivity and 100% specificity for endocan to predict pulmonary infection (area under the curve 0.84), with a cutoff value of 15.9 ng/mL. The time saved by assessment of the endocan dosage compared to a clinical diagnosis of pulmonary infection was 47 h. CONCLUSION: This pilot study showed that a specific study to assess the link between endocan plasma levels and pulmonary infection after cardiac surgery in CKD patients is of potential utility.

Presepsin (sCD14-ST) secretion and kinetics by peripheral blood mononuclear cells and monocytic THP-1 cell line.

Presepsin could help for early diagnosis of systemic infection. Little is known regarding its kinetics. We studied presepsin concentration after challenge with bacterial agonist lipopolysaccharide (LPS) stimulation in peripheral mononuclear cells (PMNC) collected from 5 healthy volunteers and in a human cell line of monocytic cells (THP1). In PMNC, an exposure to LPS (100 ng/mL) induced an increase of median presepsin levels as early as hour 1 (+31%, p=0.007), concomitantly to IL-6 synthesis. In THP1 cells, presepsin was detected at 1 hour after LPS exposure, and peaked at 3 hours, in THP1 cells. In conclusion, we report here that presepsin, a surrogate marker of the host response to bacteria, increases early in PMNC and in a monocytic cell lineage. Our findings might confirm the potential usefulness of presepsin bedside as an early marker of infectious diseases.

Diagnosis performance of high sensitivity troponin assay in out-of-hospital cardiac arrest patients.

PURPOSE: Early identification of the cause of out-of-hospital cardiac arrest (OHCA) remains a challenge. Our aim was to determine whether high-sensitivity cardiac troponin T (HsTnT) was useful to diagnose a recent coronary artery occlusion as the cause of OHCA. METHODS: Retrospective study including OHCA patients evaluated by systematic coronary angiogram at hospital admission. HsTnT was assessed at ICU admission. Predictive factors of a recent coronary occlusion were identified by logistic regression. Net reclassification improvement (NRI) was calculated to estimate the potential enhancement of prediction with HsTnT. RESULTS: During the 5 year study period, 272 patients (median age 60 y, 76.5% men) were included, and a culprit coronary occlusion was found in 133 (48.9%). The optimum HsTnT cut-off to predict a recent coronary occlusion was 575 ng/l (sensitivity 65.4%, specificity 65.5%). In multivariate analysis, current smoking (OR 3.2 95%, 95%CI 1.62-6.33), time from collapse to BLS<3 min (OR 2.11, 95%CI 1.10-4.05), initial shockable rhythm (OR 5.29, 95%CI 2.06-13.62), ST-segment elevation (OR 2.44, 95%CI 1.18-5.03), post-resuscitation shock onset (OR 2.03, 95%CI 1.01-4.07) and HsTnT≥575 ng/l (OR 2.22, 95%CI 1.16-4.27) were associated with the presence of a recent coronary occlusion. Nevertheless, adding HsTnT to established risk factors of recent coronary occlusion identified above provided a non-significant NRI of -0.43%. CONCLUSIONS: Admission HsTnT is increased after OHCA and is an independent factor of a recent coronary occlusion. However, HsTnT does not seem to be a strong enough diagnostic tool to select candidates for emergent coronary angiogram in OHCA survivors.

Can early cardiac troponin I measurement help to predict recent coronary occlusion in out-of-hospital cardiac arrest survivors?

OBJECTIVE: Recent guidelines recommend the immediate performance of a coronary angiography when an acute myocardial infarction is suspected as a cause of out-of-hospital cardiac arrest. However, prehospital factors such as postresuscitation electrocardiogram pattern or clinical features are poorly sensitive in this setting. We searched to evaluate if an early measurement of cardiac troponin I can help to detect a recent coronary occlusion in out-of-hospital cardiac arrest. DESIGN: Retrospective analysis of a prospective electronic registry database. SETTING: University cardiac arrest center. PATIENTS: Between January 2003 and December 2008, 422 out-of-hospital cardiac arrest survivors without obvious extra-cardiac cause have been consecutively studied. An immediate coronary angiography has been systematically performed. The primary outcome was the finding of a recent coronary occlusion. INTERVENTION: First, blood cardiac troponin I levels at admission were analyzed to assess the optimum cutoff for identifying a recent coronary occlusion. Second, a logistic regression was performed to determine early predictive factors of a recent coronary occlusion (including cardiac troponin I) and their respective contribution. MEASUREMENTS AND MAIN RESULTS: An ST-segment elevation was present in 127 of 422 patients (30%). During coronary angiography, a recent occlusion has been detected in 193 of 422 patients (46%). The optimum cardiac troponin I threshold was determined at 4.66 ng·mL(-1) (sensitivity 66.7%, specificity 66.4%). In multivariate analyses, in addition of smoking and epinephrine initial dose, cardiac troponin I (odds ratio 3.58 [2.03-6.32], p < .001) and ST-segment elevation (odds ratio 10.19 [5.39-19.26], p < .001) were independent predictive factors of a recent coronary occlusion. CONCLUSIONS: In this large cohort of out-of-hospital cardiac arrest patients, isolated early cardiac troponin I measurement is modestly predictive of a recent coronary occlusion. Furthermore, the contribution of this parameter even in association with other factors does not seem helpful to predict recent occlusion. As a result and given the high benefit of percutaneous coronary intervention for such patients, the dosage of cardiac troponin I at admission could not help in the decision of early coronary angiogram.

Hypoxia induces nitric oxide synthase in rheumatoid synoviocytes: consequences on NADPH oxidase regulation.

We investigated the effects of hypoxia on inducible NO synthase (iNOS) activity and expression in rheumatoid arthritis (RA) synoviocytes. We further studied the relationship between nitrosative stress and NADPH oxidase (NOX) in such conditions. Human cultured synoviocytes were treated for 24 hours with IL-1ß, TNF-α or neither, and submitted to hypoxia or normoxia for the last 6 hours. Nitrite production and iNOS expression were increased under hypoxia conditions in RA cells in comparison to normoxia. Hypoxia did not potentate the basal and cytokine-induced superoxide productions, while NOXs' subunit expression and p47-phox phosphorylation were increased. Nitrosylation of NOXs and p47-phox was not raised under hypoxia conditions. Finally, peroxynitrite production was significantly increased under hypoxia conditions, in comparison to normoxia. Our results provide evidence for upregulation of iNOS and NOX activities in RA synoviocytes under hypoxia conditions, associated to an increased peroxynitrite production. Synovial cell metabolism under hypoxia conditions might be different from that in normoxia.

Clopidogrel protects from cell apoptosis and oxidative damage in a mouse model of renal ischaemia-reperfusion injury.

Renal ischaemia-reperfusion injury (IRI) is consecutive to tissue oxidative damage and cell apoptosis that lead to acute renal failure (ARF) in renal allografts. The aim of this study was to investigate the beneficial effects of a pretreatment by clopidogrel on renal IRI in mice. IRI was induced by bilateral renal ischaemia for 45 min followed by reperfusion. Sixty-two healthy male BALB/c mice were randomly assigned to one of the following groups: PBS + ischaemia-reperfusion (IR); clopidogrel + IR; PBS + sham IR; clopidogrel + sham IR. Clopidogrel (25 mg/kg) or PBS was administered per os to the animals via a gastric cannula 24 h before operation. All mice were given a single dose of clopidogrel or PBS. Renal function histological damage, renal cell apoptosis, renal antioxidant activities, and CD41 expression were determined 24 h after reperfusion. The survival rates were evaluated over 7 days. Animals pretreated with clopidogrel had lower plasma levels of blood urea nitrogen (BUN) and creatinine, lower histopathological scores, and improved survival rates following IR. Renal cell apoptosis induced by IR was decreased in kidneys of mice pretreated by clopidogrel, with an increase in Bcl-2 and Bcl-xL expression and a decrease in caspase-3, caspase-8, and Bax expression. Renal reduced glutathione, superoxide dismutase, and catalase activities were unmodified by the pretreatment with clopidogrel. However, clopidogrel resulted in an increased total antioxidant capacity of the kidney. Furthermore, pretreatment by clopidogrel decreased the number of CD41-positive cells. Thus, clopidogrel exerts protective effects on renal IRI in mice by abrogating renal cell apoptosis as a consequence of improved renal antioxidant capacity and could be tried as a novel therapeutic tool in renal IRI.

Implication of cytosolic phospholipase A2 (cPLA2) in the regulation of human synoviocyte NADPH oxidase (Nox2) activity.

NADPH oxidase Nox2 is involved in the production of superoxide by rheumatoid synovial cells, constitutively and after pro-inflammatory cytokine treatment. The aims of the study were to evaluate the capacity of these cells to produce the superoxide anion in response to arachidonic acid (AA), and to study the involvement of cytosolic phospholipase A(2) (cPLA(2)) in the cytokine regulation of Nox2. Superoxide production was quantified in synovial cells obtained from six patients with rheumatoid arthritis (RA) and six with osteoarthritis (OA), stimulated with (i) AA, and (ii) PLA(2) inhibitors prior to IL-1beta or TNF-alpha treatment. Total cellular AA concentrations and PLA(2) activity were measured; effects of cytokines and NADPH oxidase inhibitors on the AA-activatable proton channel opening were also studied. Our results demonstrated that AA enhanced superoxide production in RA and OA cells; this production was significantly inhibited by iodonium diphenyl and apocynin. cPLA(2) inhibitors inhibited both IL-1beta and TNF-alpha-induced superoxide production in RA and OA cells. Basal PLA(2) activity was significantly more important in RA cells than in OA cells; PLA(2) activity was increased in IL-1beta and TNF-alpha pre-treated RA cells, and cPLA(2) inhibitors inhibited this activity. Opening of the AA-activatable proton channel was amplified when RA cells were pre-treated with both IL-1beta and TNF-alpha, and iodonium diphenyl and apocynin inhibited these cytokine effects. We concluded that AA is an important cofactor for synovial NADPH oxidase activity. Despite their direct effects on p47-phox phosphorylation, cytokines can also regulate the Nox2 activity though the AA-activatable associated H(+) channel.

Effects of pro- and anti-inflammatory cytokines and nitric oxide donors on hyaluronic acid synthesis by synovial cells from patients with rheumatoid arthritis.

The aim of the present study was to investigate the effects of (i) the pro-inflammatory cytokines IL (interleukin)-1beta, TNF-alpha (tumour necrosis factor-alpha), IFN-gamma (interferon-gamma) and anti-inflammatory cytokines IL-4 and IL-13, and (ii) NO (nitric oxide) donors on HA (hyaluronic acid) production by synovial cells from patients with rheumatoid arthritis. Synovial cells obtained from five patients with rheumatoid arthritis were incubated for 24 h without or with IL-1beta, TNF-alpha, IFN-gamma, or with this mixture for 24 h plus IL-4 or IL-13 for the last 6 h. The same cells were also incubated for 3-24 h without or with SNP (sodium nitroprusside) or SNAP (S-nitroso-N-acetyl-DL-penicillamine). HA secretion was determined by an immunoenzymic assay based on HA-specific binding by proteoglycan isolated from bovine cartilage. IL-1beta, TNF-alpha and IFN-gamma alone or in combination stimulated HA synthesis, whereas IL-4 and IL-13 dose-dependently inhibited HA production induced by Th1 cytokines. HA production was significantly increased by the presence of 1 mM SNP after 6 and 12 h (maximal effect). HA production was significantly increased by the presence of 0.01 and 0.1 mM SNAP after 12 h of incubation, and cells treated with 1 mM SNAP showed a maximal HA production after 24 h of incubation. In conclusion, the present study provides data concerning the regulatory role of pro- and anti-inflammatory cytokines and NO donors on HA metabolism in rheumatoid synovial cells and may help in understanding the pathophysiology of rheumatoid arthritis.