Albumin versus saline infusion for sepsis-related peripheral tissue hypoperfusion: a proof-of-concept prospective study.

BACKGROUND: Albumin has potential endothelial protective effects through antioxidant and anti-inflammatory properties. However, the effect of albumin on peripheral tissue perfusion in human sepsis remains poorly known. METHODS: Bi-centric prospective study included patients with sepsis with or without shock and prolonged CRT > 3 s despite initial resuscitation. Clinicians in charge of the patients were free to infuse either saline 500 mL or human serum albumin 20% 100 mL over 15 min. Global hemodynamic parameters as well as peripheral tissue perfusion were analyzed after 1 (H1) and 4 h (H4). The primary endpoint was CRT normalization (< 3 s) at H1. RESULTS: 62 patients were screened, and 50 patients (13 sepsis and 37 septic shock) were included, 21 in the saline group and 29 in the albumin group. SOFA score was 8 [5-11], and SAPS II was 53 [45-70]. Median age was 68 [60-76] years with a higher proportion of men (74%). The primary sources of infection were respiratory (54%) and abdominal (24%). At baseline, comorbidities, clinical and biological characteristics were similar between groups. At H1, CRT normalization (< 3 s) was more frequent in patients receiving albumin as compared to patients treated by saline (63 vs 29%, P = 0.02). The decrease in fingertip CRT was more important in the albumin group when compared to saline group (- 1.0 [- 0.3; - 1.5] vs - 0.2 [- 0.1; - 1.1] seconds, P = 0.04) as well as decrease in mottling score. At H4, beneficial effects of albumin on peripheral tissue perfusion were maintained and urinary output trended to be higher in the albumin group (1.1 [0.5-1.8] vs 0.7 [0.5-0.9] ml/kg/h, P = 0.08). Finally, arterial lactate level did not significantly change between H0 and H4 in the saline group but significantly decreased in the albumin group (P = 0.03). CONCLUSION: In patients with resuscitated sepsis, albumin infusion might lead to greater improvement of tissue hypoperfusion compared to saline. CLINICALTRIALS: gov Identifier: NCT05094856.

Reversible skin microvascular hyporeactivity in patients with immune-mediated thrombocytopenic thrombotic purpura.

BACKGROUND: Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare disease characterized by arteriolar and capillary microthrombosis precipitating organ failure. However, the contribution of endothelial dysfunction on impaired microvascular blood flow in iTTP patients has been poorly explored. This pilot observational study aimed to explore endothelial-mediated vasoreactivity in iTTP patients at admission and its changes after plasma exchange therapy (PE). METHODS: We conducted a prospective observational study in patients (> 18-year old) admitted in ICU for iTTP. Using laser Doppler flowmetry and acetylcholine (Ach) iontophoresis in the forearm, we recorded the skin microvascular blood flow and the endothelium-mediated vasoreactivity at admission and after PE. Demographics, biological, clinical courses, and outcomes were also collected. As a control group, we used a previously published cohort of young diabetic patients after correction of ketoacidosis. RESULTS: Eighteen confirmed iTTP patients and 34 controls were included in the study, mainly female (72%) aged 43 ± 16-year-old. At admission, 55% had neurological abnormalities, 50% cardiac issues and 27.8% an acute kidney injury. Median platelet count was 19 G/mL [10-37]. Baseline microvascular blood flow was decreased in iTTP patients when compared to controls (5.97 ± 4.5 vs. 10.1 ± 6.3 PU, P = 0.03), associated with markedly impaired endothelial-mediated skin microvascular reactivity (AUC: 9627 ± 8122 vs. 16,475 ± 11,738, P = 0.03). Microvascular reactivity improved after the first PE session (AUC: 9627 ± 8122 vs 16,558 ± 10,699, P = 0.007, respectively, baseline and post-PE1) and much more after the second session (26,431 ± 23,181, P = 0.04 post-PE1 vs post-PE2). Hemolysis biomarkers (LDH and bilirubin) negatively correlated with skin microvascular flow and vasoreactivity. CONCLUSION: We highlighted a marked yet reversible skin endothelium-mediated microvascular hyporeactivity in iTTP patients that could participate in organ injury pathophysiology.

Prognostic value of capillary refill time in adult patients: a systematic review with meta-analysis.

PURPOSE: Acute circulatory failure leads to tissue hypoperfusion. Capillary refill time (CRT) has been widely studied, but its predictive value remains debated. We conducted a meta-analysis to assess the ability of CRT to predict death or adverse events in a context at risk or confirmed acute circulatory failure in adults. METHOD: MEDLINE, EMBASE, and Google scholar databases were screened for relevant studies. The pooled area under the ROC curve (AUC ROC), sensitivity, specificity, threshold, and diagnostic odds ratio using a random-effects model were determined. The primary analysis was the ability of abnormal CRT to predict death in patients with acute circulatory failure. Secondary analysis included the ability of CRT to predict death or adverse events in patients at risk or with confirmed acute circulatory failure, the comparison with lactate, and the identification of explanatory factors associated with better accuracy. RESULTS: A total of 60,656 patients in 23 studies were included. Concerning the primary analysis, the pooled AUC ROC of 13 studies was 0.66 (95%CI [0.59; 0.76]), and pooled sensitivity was 54% (95%CI [43; 64]). The pooled specificity was 72% (95%CI [55; 84]). The pooled diagnostic odds ratio was 3.4 (95%CI [1.4; 8.3]). Concerning the secondary analysis, the pooled AUC ROC of 23 studies was 0.69 (95%CI [0.65; 0.74]). The prognostic value of CRT compared to lactate was not significantly different. High-quality CRT was associated with a greater accuracy. CONCLUSION: CRT poorly predicted death and adverse events in patients at risk or established acute circulatory failure. Its accuracy is greater when high-quality CRT measurement is performed.

Extracranial anticoagulant related bleedings admitted to intensive care units: a French multicenter retrospective study.

BACKGROUND: Anticoagulants are widely used but can lead to iatrogenic events such as bleeding. Limited data exists regarding the characteristics and management of patients admitted to intensive care units (ICU) for severe anticoagulant-related extracranial bleeding. METHODS: A retrospective observational study was conducted in five French ICUs. From January 2007 to December 2018, all patients aged over 18 years admitted to ICU for extracranial bleeding while receiving therapeutic anticoagulation were included. RESULTS: 486 patients were included, mainly male (61%) with an average age of 73 ± 13 years. Most patients had comorbidities, including hypertension (68%), heart disease (49%) and diabetes (33%). Patients were treated by vitamin K antagonists (VKA, 54%), heparins (25%) and direct oral anticoagulants (DOAC, 7%). The incidence of patients admitted to ICU for anticoagulant-related bleeding increased from 3.2/1000 admissions in 2007 to 5.8/1000 in 2018. This increase was particularly high for DOAC class. Upon admission, patients exhibited severe organ failure, as evidenced by a high SOFA score (7 ± 4) and requirement for organ support therapies such as vasopressors (31.5%) and invasive mechanical ventilation (34%). Adherence to guidelines for the specific treatment of anticoagulant-related bleeding was generally low. ICU mortality was 27%. In multivariate analysis, five factors were independently associated with mortality: chronic hypertension, need for vasopressors, impaired consciousness, hyperlactatemia and prolonged aPTT > 1.2. CONCLUSION: Anticoagulant-related extracranial bleeding requiring ICU admission is a serious complication responsible for organ failure and significant mortality. Its incidence is rising. The therapeutic management is suboptimal and could be improved by educational programs.

Improvement of central vein ultrasound-guided puncture success using a homemade needle guide-a simulation study.

BACKGROUND: Out-of-plane (OOP) approach is frequently used for ultrasound-guided insertion of central venous catheter (CVC) owing to its simplicity but does not avoid mechanical complication. In-plane (IP) approach might improve safety of insertion; however, it is less easy to master. We assessed, a homemade needle guide device aimed to improve CVC insertion using IP approach. METHOD: We evaluated in a randomized simulation trial, the impact of a homemade needle guide on internal jugular, subclavian and femoral vein puncture, using three approaches: out-of-plane free hand (OOP-FH), in-plane free hand (IP-FH), and in-plane needle guided (IP-NG). Success at first pass, the number of needle redirections and arterial punctures was recorded. Time elapsed (i) from skin contact to first skin puncture, (ii) from skin puncture to successful venous puncture and (iii) from skin contact to venous return were measured. RESULTS: Thirty operators performed 270 punctures. IP-NG approach resulted in high success rate at first pass (jugular: 80%, subclavian: 95% and femoral: 100%) which was higher than success rate observed with OOP-FH and IP-FH regardless of the site (p = .01). Compared to IP-FH and OOP-FH, the IP-NG approach decreased the number of needle redirections at each site (p = .009) and arterial punctures (p = .001). Compared to IP-FH, the IP-NG approach decreased the total procedure duration for puncture at each site. CONCLUSION: In this simulation study, IP approach using a homemade needle guide for ultrasound-guided central vein puncture improved success rate at first pass, reduced the number of punctures/redirections and shortened the procedure duration compared to OOP and IP free-hand approaches.

Sonometric assessment of cough predicts extubation failure: SonoWean-a proof-of-concept study.

BACKGROUND: Extubation failure is associated with increased mortality. Cough ineffectiveness may be associated with extubation failure, but its quantification for patients undergoing weaning from invasive mechanical ventilation (IMV) remains challenging. METHODS: Patients under IMV for more than 24 h completing a successful spontaneous T-tube breathing trial (SBT) were included. At the end of the SBT, we performed quantitative sonometric assessment of three successive coughing efforts using a sonometer. The mean of the 3-cough volume in decibels was named Sonoscore. RESULTS: During a 1-year period, 106 patients were included. Median age was 65 [51-75] years, mainly men (60%). Main reasons for IMV were acute respiratory failure (43%), coma (25%) and shock (17%). Median duration of IMV at enrollment was 4 [3-7] days. Extubation failure occurred in 15 (14%) patients. Baseline characteristics were similar between success and failure extubation groups, except percentage of simple weaning which was lower and MV duration which was longer in extubation failure patients. Sonoscore was significantly lower in patients who failed extubation (58 [52-64] vs. 75 [70-78] dB, P < 0.001). After adjustment on MV duration and comorbidities, Sonoscore remained associated with extubation failure. Sonoscore was predictive of extubation failure with an area under the ROC curve of 0.91 (IC95% [0.83-0.99], P < 0.001). A threshold of Sonoscore < 67.1 dB predicted extubation failure with a sensitivity of 0.93 IC95% [0.70-0.99] and a specificity of 0.82 IC95% [0.73-0.90]. CONCLUSION: Sonometric assessment of cough strength might be helpful to identify patients at risk of extubation failure in patients undergoing IMV.

Performance of Early Capillary Refill Time Measurement on Outcomes in Cardiogenic Shock: An Observational, Prospective Multicentric Study.

Rationale: Identification of cardiogenic shock severity is a critical step to adapt the management level upon admission. Peripheral tissue perfusion signs, simple and reliable markers of tissue hypoperfusion have never been extensively assessed during cardiogenic shock. Objectives: To assess the correlation of capillary refill time values with 90-day mortality in cardiogenic shock patients or the need for venoarterial extracorporeal membrane oxygenation (VA-ECMO) support. Also to assess the correlation between capillary refill time and hemodynamic parameters. Methods: All consecutive patients with cardiogenic shock admitted to the intensive care unit of two tertiary teaching hospitals were included in a prospective observational study. Macro-hemodynamic parameters (such as heart rate, blood pressure, left ventricular ejection fraction, and cardiac index) and peripheral tissue perfusion signs, such as capillary refill time on the index fingertip, mottling, and Pv-aCO2 (the difference between partial pressure of CO2 between venous and arterial blood) were recorded at inclusion (0 hour), 6 hours, 12 hours, 24 hours, and 48 hours. The composite primary endpoint was the association between 90-day mortality or the need for VA-ECMO support. Measurements and Main Results: A total of 61 patients were included; at inclusion, simplified acute physiology score II was 64 (52-77) points. The primary endpoint was met by 42% of patients. Capillary refill time values were significantly higher at all time points in nonsurvivors or patients needing VA-ECMO support. In univariate analysis, capillary refill time > 3 seconds at inclusion was associated with 90-day all-cause mortality or VA-ECMO support (hazard ratio, 12.38; 95% confidence interval, 2.91-52.71). Capillary refill time at inclusion was poorly associated with macrocirculatory parameters but significantly correlated with microcirculatory parameters. Further, capillary refill time added incremental value to Cardshock score, with an AUC combination at 0.93. Conclusions: In patients with cardiogenic shock admitted to the ICU, our preliminary data suggest that a prolonged capillary refill time >3 seconds was associated with an early prediction of 90-day mortality or the need for VA-ECMO support.

Endothelial Cell Indoleamine 2, 3-Dioxygenase 1 Alters Cardiac Function After Myocardial Infarction Through Kynurenine.

BACKGROUND: Ischemic cardiovascular diseases, particularly acute myocardial infarction (MI), is one of the leading causes of mortality worldwide. Indoleamine 2, 3-dioxygenase 1 (IDO) catalyzes 1 rate-limiting step of L-tryptophan metabolism, and emerges as an important regulator of many pathological conditions. We hypothesized that IDO could play a key role to locally regulate cardiac homeostasis after MI. METHODS: Cardiac repair was analyzed in mice harboring specific endothelial or smooth muscle cells or cardiomyocyte or myeloid cell deficiency of IDO and challenged with acute myocardial infarction. RESULTS: We show that kynurenine generation through IDO is markedly induced after MI in mice. Total genetic deletion or pharmacological inhibition of IDO limits cardiac injury and cardiac dysfunction after MI. Distinct loss of function of IDO in smooth muscle cells, inflammatory cells, or cardiomyocytes does not affect cardiac function and remodeling in infarcted mice. In sharp contrast, mice harboring endothelial cell-specific deletion of IDO show an improvement of cardiac function as well as cardiomyocyte contractility and reduction in adverse ventricular remodeling. In vivo kynurenine supplementation in IDO-deficient mice abrogates the protective effects of IDO deletion. Kynurenine precipitates cardiomyocyte apoptosis through reactive oxygen species production in an aryl hydrocarbon receptor-dependent mechanism. CONCLUSIONS: These data suggest that IDO could constitute a new therapeutic target during acute MI.

Vitamin C improves microvascular reactivity and peripheral tissue perfusion in septic shock patients.

BACKGROUND: Vitamin C has potential protective effects through antioxidant and anti-inflammatory properties. However, the effect of vitamin C supplementation on microvascular function and peripheral tissue perfusion in human sepsis remains unknown. We aimed to determine vitamin C effect on microvascular endothelial dysfunction and peripheral tissue perfusion in septic shock patients. METHODS: Patients with septic shock were prospectively included after initial resuscitation. Bedside peripheral tissue perfusion and skin microvascular reactivity in response to acetylcholine iontophoresis in the forearm area were measured before and 1 h after intravenous vitamin C supplementation (40 mg/kg). Norepinephrine dose was not modified during the studied period. RESULTS: We included 30 patients with septic shock. SOFA score was 11 [8-14], SAPS II was 66 [54-79], and in-hospital mortality was 33%. Half of these patients had vitamin C deficiency at inclusion. Vitamin C supplementation strongly improved microvascular reactivity (AUC 2263 [430-4246] vs 5362 [1744-10585] UI, p = 0.0004). In addition, vitamin C supplementation improved mottling score (p = 0.06), finger-tip (p = 0.0003) and knee capillary refill time (3.7 [2.6-5.5] vs 2.9 [1.9-4.7] s, p < 0.0001), as well as and central-to-periphery temperature gradient (6.1 [4.9-7.4] vs 4.6 [3.4-7.0] °C, p < 0.0001). The beneficial effects of vitamin C were observed both in patients with or without vitamin C deficiency. CONCLUSION: In septic shock patients being resuscitated, vitamin C supplementation improved peripheral tissue perfusion and microvascular reactivity whatever plasma levels of vitamin C. ClinicalTrials.gov Identifier: NCT04778605 registered 26 January 2021.

Impairment of neutrophil functions and homeostasis in COVID-19 patients: association with disease severity.

BACKGROUND: A dysregulated immune response is emerging as a key feature of critical illness in COVID-19. Neutrophils are key components of early innate immunity that, if not tightly regulated, contribute to uncontrolled systemic inflammation. We sought to decipher the role of neutrophil phenotypes, functions, and homeostasis in COVID-19 disease severity and outcome. METHODS: By using flow cytometry, this longitudinal study compares peripheral whole-blood neutrophils from 90 COVID-19 ICU patients with those of 22 SARS-CoV-2-negative patients hospitalized for severe community-acquired pneumonia (CAP) and 38 healthy controls. We also assessed correlations between these phenotypic and functional indicators and markers of endothelial damage as well as disease severity. RESULTS: At ICU admission, the circulating neutrophils of the COVID-19 patients showed continuous basal hyperactivation not seen in CAP patients, associated with higher circulating levels of soluble E- and P-selectin, which reflect platelet and endothelial activation. Furthermore, COVID-19 patients had expanded aged-angiogenic and reverse transmigrated neutrophil subsets-both involved in endothelial dysfunction and vascular inflammation. Simultaneously, COVID-19 patients had significantly lower levels of neutrophil oxidative burst in response to bacterial formyl peptide. Moreover patients dying of COVID-19 had significantly higher expansion of aged-angiogenic neutrophil subset and greater impairment of oxidative burst response than survivors. CONCLUSIONS: These data suggest that neutrophil exhaustion may be involved in the pathogenesis of severe COVID-19 and identify angiogenic neutrophils as a potentially harmful subset involved in fatal outcome.

Exaggerated Microvascular Vasodilating Responses in Cirrhotic Patients With Septic Shock.

OBJECTIVES: Cirrhosis is associated with hemodynamic and vascular disorders. However, microvascular reactivity of cirrhotic patients in the context of sepsis has poorly been investigated. DESIGN: Prospective observational study. SETTING: Medical ICU in a tertiary teaching hospital. PATIENTS: We prospectively included adult patients admitted in the ICU for septic shock with and without cirrhosis. After initial resuscitation, global hemodynamic parameters were recorded and skin microvascular reactivity to local acetylcholine iontophoresis was measured. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Thirty patients with septic shock were included (60% male), 10 with cirrhosis and 20 without, with a median age of 61 years (54-74 yr). Cirrhotic patients were mainly classed as Child-Pugh C (80%) and all of them had ascites. Sequential Organ Failure Assessment score and ICU mortality of cirrhotic patients were higher than the noncirrhotic patients, respectively (6.5 [5.0-8.3] vs 11.5 [9.0-14.0]; p < 0.01; 15% vs 70%; p < 0.01). Peripheral tissue perfusion and global hemodynamic parameters were not different between the cirrhotic and noncirrhotic patients but arterial lactate level was three times higher in patients with cirrhosis (6.0 mmol/L [3.9-8.0 mmol/L] vs 2.0 mmol/L [0.9-3.5 mmol/L]; p < 0.01). Basal skin microvascular blood flow was not statistically different between the groups (4.94 perfusion units [3.45-8.73 perfusion units] vs 6.95 perfusion units [5.24-8.38 perfusion units]; p = 0.29). After acetylcholine simulation, skin microvascular blood flow increased more in cirrhotic patients than in noncirrhotic patients (644% [217-966%] vs 169% [73-505%], p = 0.03). Global microvascular reactivity was seven times higher in cirrhotic patients (area under the curve, 16,412 perfusion units [13,898-19,041 perfusion units] vs 2,664 perfusion units [969-4,604 perfusion units]; p < 0.001). CONCLUSIONS: We identified an exaggerated vasodilating microvascular response in cirrhotic patients with septic shock. Such a result may explain vasopressor resistance and paves the way for future therapeutic trials, targeting nitric oxide pathway specifically in this population.

Outcome of allogeneic hematopoietic stem cell transplant recipients admitted to the intensive care unit with a focus on haploidentical graft and sequential conditioning regimen: results of a retrospective study.

Haploidentical transplantation has extended the availability of allogeneic hematopoietic stem cell transplant (alloHCT) to almost all patients. Sequential conditioning regimens have been proposed for the treatment of hematological active disease. Whether these new transplantation procedures affect the prognosis of critically ill alloHCT recipients remains unknown. We evaluated this question in a retrospective study including consecutive alloHCT patients admitted to the intensive care unit of a tertiary academic center from 2010 to 2017. During the study period, 412 alloHCTs were performed and 110 (27%) patients-median age 55 (36-64) years-were admitted to ICU in a median time of 58.5 (14-245) days after alloHCT. Twenty-nine (26%) patients had received a haploidentical graft and 34 (31%) a sequential conditioning. Median SOFA score was 9 (6-11). Invasive mechanical ventilation (MV) was required in 61 (55%) patients. Fifty-six (51%) patients died in the hospital. Independent factors associated with in-hospital mortality were as follows: MV (OR=8.44 [95% CI 3.30-23.19], p<0.001), delta SOFA between day 3 and day 1 (OR=1.60 [95% CI 1.31-2.05], p<0.0001), and sequential conditioning (OR=3.7 [95% CI 1.14-12.92], p=0.033). Sequential conditioning was also independently associated with decreased overall survival (HR=1.86 [95% CI 1.05-3.31], p=0.03). Other independent factors associated with reduced overall survival were HCT-specific comorbidity index ≥2 (HR=1.76 [95% CI 1.10-2.84], p=0.02), acute GVHD grade ≥2 (HR=1.88 [95% CI 1.14-3.10], p=0.01), MV (HR=2.37 [95% CI 1.38-4.07, p=0.002), and vasopressors (HR=2.21 [95% CI 1.38-3.54], p=0.001). Haploidentical transplantation did not affect outcome. Larger multicenter studies are warranted to confirm these results.

Acute cholangitis in intensive care units: clinical, biological, microbiological spectrum and risk factors for mortality: a multicenter study.

BACKGROUND: Little is known on the outcome and risk factors for mortality of patients admitted in Intensive Care units (ICUs) for Acute cholangitis (AC). METHODS: Retrospective multicenter study included adults admitted in eleven intensive care units for a proven AC from 2005 to 2018. Risk factors for in-hospital mortality were identified using multivariate analysis. RESULTS: Overall, 382 patients were included, in-hospital mortality was 29%. SOFA score at admission was 8 [5-11]. Biliary obstruction was mainly related to gallstone (53%) and cancer (22%). Median total bilirubin and PCT were respectively 83 µmol/L [50-147] and 19.1 µg/L [5.3-54.8]. Sixty-three percent of patients (n = 252) had positive blood culture, mainly Gram-negative bacilli (86%) and 14% produced extended spectrum beta lactamase bacteria. At ICU admission, persisting obstruction was frequent (79%) and biliary decompression was performed using therapeutic endoscopic retrograde cholangiopancreatography (76%) and percutaneous transhepatic biliary drainage (21%). Adjusted mortality significantly decreased overtime, adjusted OR for mortality per year was 0.72 [0.54-0.96] (p = 0.02). In a multivariate analysis, factors at admission associated with in-hospital mortality were: SOFA score (OR 1.14 [95% CI 1.05-1.24] by point, p = 0.001), lactate (OR 1.21 [95% CI 1.08-1.36], by 1 mmol/L, p < 0.001), total serum bilirubin (OR 1.26 [95% CI 1.12-1.41], by 50 µmol/L, p < 0.001), obstruction non-related to gallstones (p < 0.05) and AC complications (OR 2.74 [95% CI 1.45-5.17], p = 0.002). Time between ICU admission and biliary decompression > 48 h was associated with in-hospital mortality (adjusted OR 2.73 [95% CI 1.30-6.22], p = 0.02). CONCLUSIONS: In this large retrospective multicenter study, we found that AC-associated mortality significantly decreased overtime. Severity of organ failure, cause of obstruction and local complications of AC are risk factors for mortality, as well as delayed biliary drainage > 48 h.

Endothelial Responses in Sepsis.

Endothelial cells (ECs) are vascular, nonconventional immune cells that play a major role in the systemic response after bacterial infection to limit its dissemination. Triggered by exposure to pathogens, microbial toxins, or endogenous danger signals, EC responses are polymorphous, heterogeneous, and multifaceted. During sepsis, ECs shift toward a proapoptotic, proinflammatory, proadhesive, and procoagulant phenotype. In addition, glycocalyx damage and vascular tone dysfunction impair microcirculatory blood flow, leading to organ injury and, potentially, life-threatening organ failure. This review aims to cover the current understanding of the EC adaptive or maladaptive response to acute inflammation or bacterial infection based on compelling recent basic research and therapeutic clinical trials targeting microvascular and endothelial alterations during septic shock.

Genetic Depletion or Hyperresponsiveness of Natural Killer Cells Do Not Affect Atherosclerosis Development.

RATIONALE: Chronic inflammation is central in the development of atherosclerosis. Both innate and adaptive immunities are involved. Although several studies have evaluated the functions of natural killer (NK) cells in experimental animal models of atherosclerosis, it is not yet clear whether NK cells behave as protective or proatherogenic effectors. One of the main caveats of previous studies was the lack of specificity in targeting loss or gain of function of NK cells. OBJECTIVES: We used 2 selective genetic approaches to investigate the role of NK cells in atherosclerosis: (1) Ncr1iCre/+R26lsl-DTA/+ mice in which NK cells were depleted and (2) Noé mice in which NK cells are hyperresponsive. METHODS AND RESULTS: No difference in atherosclerotic lesion size was found in Ldlr-/- (low-density lipoprotein receptor null) mice transplanted with bone marrow (BM) cells from Ncr1iCreR26Rlsl-DTA , Noé, or wild-type mice. Also, no difference was observed in plaque composition in terms of collagen content, macrophage infiltration, or the immune profile, although Noé chimera had more IFN (interferon)-γ-producing NK cells, compared with wild-type mice. Then, we investigated the NK-cell selectivity of anti-asialoganglioside M1 antiserum, which was previously used to conclude the proatherogenicity of NK cells. Anti-asialoganglioside M1 treatment decreased atherosclerosis in both Ldlr-/- mice transplanted with Ncr1iCreR26Rlsl-DTA or wild-type bone marrow, indicating that its antiatherogenic effects are unrelated to NK-cell depletion, but to CD8+ T and NKT cells. Finally, to determine whether NK cells could contribute to the disease in conditions of pathological NK-cell overactivation, we treated irradiated Ldlr-/- mice reconstituted with either wild-type or Ncr1iCreR26Rlsl-DTA bone marrow with the viral mimic polyinosinic:polycytidylic acid and found a significant reduction of plaque size in NK-cell-deficient chimeric mice. CONCLUSIONS: Our findings, using state-of-the-art mouse models, demonstrate that NK cells have no direct effect on the natural development of hypercholesterolemia-induced atherosclerosis, but may play a role when an additional systemic NK-cell overactivation occurs.

Anticytokine Immune Therapy and Atherothrombotic Cardiovascular Risk.

Accumulating observations in humans and animals indicate that inflammation plays a key role in atherosclerosis development and subsequent complications. Moreover, the use of loss- or gain-of-function genetically modified, atherosclerosis-prone mice has provided strong experimental evidence for a causal role of innate and adaptive immunity in atherosclerosis and has revealed the pathogenic activity of proinflammatory cytokines, including TNF (tumor necrosis factor)-α, IL (interleukin)-1ß, IL-6, and IL-18, and the atheroprotective effect of anti-inflammatory cytokines, including IL-10 and TGF-ß. For the past 15 years, treatments using monoclonal antibodies specifically targeting cytokines, commonly referred as biological therapies, have transformed the treatment of chronic inflammatory diseases, such as rheumatoid arthritis or psoriasis, both conditions associated with increased cardiovascular risk. Analyzing the impact of anticytokine therapies on the cardiovascular outcomes of patients with chronic inflammatory diseases provides insight into the clinical relevance of experimental data on the role of inflammation in atherothrombotic cardiovascular diseases. CANTOS (Canakinumab Antiinflammatory Thrombosis Outcome Study) provided the first evidence that targeting inflammation in humans with atherosclerosis could improve clinical outcomes. Treatment with the anti-IL-1ß antibody canakinumab significantly reduced recurrent cardiovascular events in individuals with stable coronary artery disease well-treated with standard-of-care measures. Other clinical studies support the protective effects of treatment with anti-TNF-α and anti-IL-6 receptor monoclonal antibodies on cardiovascular risk. Blockade of the IL-23/IL-17 axis, however, warrants caution as a cardiovascular intervention. Targeting this pathway has improved psoriasis but may augment cardiovascular risk in certain patients. Thus, careful consideration of the cardiovascular risk profile may influence the choice of the most appropriate treatment for patients with chronic inflammatory diseases.Visual Overview: An online visual overview is available for this article.

Disruption of the CCL1-CCR8 axis inhibits vascular Treg recruitment and function and promotes atherosclerosis in mice.

The CC chemokine 1 (CCL1, also called I-309 or TCA3) is a potent chemoattractant for leukocytes that plays an important role in inflammatory processes and diseases through binding to its receptor CCR8. Here, we investigated the role of the CCL1-CCR8 axis in atherosclerosis. We found increased expression of CCL1 in the aortas of atherosclerosis-prone fat-fed apolipoprotein E (Apoe)-null mice; moreover, in vitro flow chamber assays and in vivo intravital microscopy demonstrated an essential role for CCL1 in leukocyte recruitment. Mice doubly deficient for CCL1 and Apoe exhibited enhanced atherosclerosis in aorta, which was associated with reduced plasma levels of the anti-inflammatory interleukin 10, an increased splenocyte Th1/Th2 ratio, and a reduced regulatory T cell (Treg) content in aorta and spleen. Reduced Treg recruitment and aggravated atherosclerosis were also detected in the aortas of fat-fed low-density lipoprotein receptor-null mice treated with CCR8 blocking antibodies. These findings demonstrate that disruption of the CCL1-CCR8 axis promotes atherosclerosis by inhibiting interleukin 10 production and Treg recruitment and function.

The Dendritic Cell Receptor DNGR-1 Promotes the Development of Atherosclerosis in Mice.

RATIONALE: Necrotic core formation during the development of atherosclerosis is associated with a chronic inflammatory response and promotes accelerated plaque development and instability. However, the molecular links between necrosis and the development of atherosclerosis are not completely understood. Clec9a (C-type lectin receptor) or DNGR-1 (dendritic cell NK lectin group receptor-1) is preferentially expressed by the CD8α+ subset of dendritic cells (CD8α+ DCs) and is involved in sensing necrotic cells. We hypothesized that sensing of necrotic cells by DNGR-1 plays a determinant role in the inflammatory response of atherosclerosis. OBJECTIVE: We sought to address the impact of total, bone marrow-restricted, or CD8α+ DC-restricted deletion of DNGR-1 on atherosclerosis development. METHODS AND RESULTS: We show that total absence of DNGR-1 in Apoe (apolipoprotein e)-deficient mice (Apoe-/-) and bone marrow-restricted deletion of DNGR-1 in Ldlr (low-density lipoprotein receptor)-deficient mice (Ldlr-/-) significantly reduce inflammatory cell content within arterial plaques and limit atherosclerosis development in a context of moderate hypercholesterolemia. This is associated with a significant increase of the expression of interleukin-10 (IL-10). The atheroprotective effect of DNGR-1 deletion is completely abrogated in the absence of bone marrow-derived IL-10. Furthermore, a specific deletion of DNGR-1 in CD8α+ DCs significantly increases IL-10 expression, reduces macrophage and T-cell contents within the lesions, and limits the development of atherosclerosis. CONCLUSIONS: Our results unravel a new role of DNGR-1 in regulating vascular inflammation and atherosclerosis and potentially identify a new target for disease modulation.

Selective EGFR (Epidermal Growth Factor Receptor) Deletion in Myeloid Cells Limits Atherosclerosis-Brief Report.

OBJECTIVE: To determine the consequences of specific inhibition of EGFR (epidermal growth factor receptor) in myeloid cells in atherosclerosis development. APPROACH AND RESULTS: Atherosclerotic lesion size was significantly reduced in irradiated Ldlr-/- mice reconstituted with LysMCre+Egfrlox/lox bone marrow, compared with chimeric Ldlr-/- mice reconstituted with LysMCre-Egfrlox/lox bone marrow, after 4 (-43%; P<0.05), 7 (-34%; P<0.05), and 12 weeks (-54%; P<0.001) of high-fat diet. Reduction of lesion size was associated with marked reduction in macrophage accumulation and necrotic core size. Specific deletion of Egfr in myeloid cells reduced TNF-α (tumor necrosis factor-α) and IL (interleukin)-6 production by stimulated macrophages but had no effect on IL-10 and IL-12p70 secretion. Finally, we found that myeloid deletion of Egfr limited cytoskeletal rearrangements and also lipid uptake by macrophages through a downregulation of the scavenger receptor CD36 (cluster of differentiation 36). CONCLUSIONS: Gene deletion of Egfr in myeloid cells limits IL-6 and TNF-α production, lipid uptake, and consecutively reduces atherosclerosis development.

Epidemiology of infective endocarditis in French intensive care units over the 1997-2014 period-from CUB-Réa Network.

BACKGROUND: Few studies focus only on severe forms of infective endocarditis, for which organ failure requires admission to an intensive care unit (ICU). This study aimed to describe demographical, comorbidities, organ failure, and pathogen-related characteristics in a population of critically ill patients admitted to ICU for infective endocarditis and to identify risk factors of in-ICU mortality. METHODS: Retrospective observational multicenter (N = 34) study of the CUB-Rea register, based on ICD-10 coding rules, between 1997 and 2014 in France including ICU patients managed for infective endocarditis. In-ICU mortality associated factors were assessed by multivariate logistic regression including an interrupted time analysis of three periods (1997-2003, 2004-2009, and 2010-2014). RESULTS: Four thousand four hundred five patients admitted in ICU for infective endocarditis were included. We observed an increase in endocarditis prevalence, as well as an increase in organ failure severity over the three periods. In addition, valve surgery was more frequently performed (27%, 31%, and 42%, P < 0.0001) while in-ICU mortality significantly decreased (28%, 29%, and 23%, P < 0.001). Since 2010, a significant increase in the trends' slope of incidence for Streptococcus sp. and Staphylococcus sp. was observed with no change concerning intracellular bacteria, Enterococcus sp. or Candida sp. slope trends. In multivariate analysis, age, SAPS2, organ failure, stroke, and Staphylococcus sp. were associated with ICU mortality. Conversely, surgery, intracardiac devices, male gender, and Streptococcus sp.-related infective endocarditis were associated with a better outcome. CONCLUSIONS: Our study reveals a shifting landscape of infective endocarditis epidemiology in French ICUs, characterized by reduced in-ICU mortality despite higher severity, more surgery, and substantial changes in microbial epidemiology.