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.

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.

COVID-19-associated Lung Microvascular Endotheliopathy: A "From the Bench" Perspective.

Rationale: Autopsy and biomarker studies suggest that endotheliopathy contributes to coronavirus disease (COVID-19)-associated acute respiratory distress syndrome. However, the effects of COVID-19 on the lung endothelium are not well defined. We hypothesized that the lung endotheliopathy of COVID-19 is caused by circulating host factors and direct endothelial infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Objectives: We aimed to determine the effects of SARS-CoV-2 or sera from patients with COVID-19 on the permeability and inflammatory activation of lung microvascular endothelial cells. Methods: Human lung microvascular endothelial cells were treated with live SARS-CoV-2; inactivated viral particles; or sera from patients with COVID-19, patients without COVID-19, and healthy volunteers. Permeability was determined by measuring transendothelial resistance to electrical current flow, where decreased resistance signifies increased permeability. Inflammatory mediators were quantified in culture supernatants. Endothelial biomarkers were quantified in patient sera. Measurements and Main Results: Viral PCR confirmed that SARS-CoV-2 enters and replicates in endothelial cells. Live SARS-CoV-2, but not dead virus or spike protein, induces endothelial permeability and secretion of plasminogen activator inhibitor 1 and vascular endothelial growth factor. There was substantial variability in the effects of SARS-CoV-2 on endothelial cells from different donors. Sera from patients with COVID-19 induced endothelial permeability, which correlated with disease severity. Serum levels of endothelial activation and injury biomarkers were increased in patients with COVID-19 and correlated with severity of illness. Conclusions: SARS-CoV-2 infects and dysregulates endothelial cell functions. Circulating factors in patients with COVID-19 also induce endothelial cell dysfunction. Our data point to roles for both systemic factors acting on lung endothelial cells and viral infection of endothelial cells in COVID-19-associated endotheliopathy.

N-Oleoyl dopamine induces IL-10 via central nervous system TRPV1 and improves endotoxemia and sepsis outcomes.

BACKGROUND: The transient receptor potential vanilloid 1 (TRPV1) participates in thermosensation and inflammatory pain, but its immunomodulatory mechanisms remain enigmatic. N-Oleoyl dopamine (OLDA), an endovanilloid and endocannabinoid, is a TRPV1 agonist that is produced in the central nervous system and the peripheral nervous system. We studied the anti-inflammatory effects and TRPV1-dependent mechanisms of OLDA in models of inflammation and sepsis. METHODS: Mice were challenged intratracheally or intravenously with LPS, or intratracheally with S. aureus to induce pneumonia and sepsis, and then were treated intravenously with OLDA. Endpoints included plasma cytokines, leukocyte activation marker expression, mouse sepsis scores, lung histopathology, and bacterial counts. The role of TRPV1 in the effects of OLDA was determined using Trpv1-/- mice, and mice with TRPV1 knockdown pan-neuronally, in peripheral nervous system neurons, or in myeloid cells. Circulating monocytes/macrophages were depleted using clodronate to determine their role in the anti-inflammatory effects of OLDA in endotoxemic mice. Levels of exogenous OLDA, and of endovanilloids and endocannabinoids, at baseline and in endotoxemic mice, were determined by LC-MS/MS. RESULTS: OLDA administration caused an early anti-inflammatory response in endotoxemic and septic mice with high serum levels of IL-10 and decreased levels of pro-inflammatory cytokines. OLDA also reduced lung injury and improved mouse sepsis scores. Blood and lung bacterial counts were comparable between OLDA- and carrier-treated mice with S. aureus pneumonia. OLDA's effects were reversed in mice with pan-neuronal TRPV1 knockdown, but not with TRPV1 knockdown in peripheral nervous system neurons or myeloid cells. Depletion of monocytes/macrophages reversed the IL-10 upregulation by OLDA in endotoxemic mice. Brain and blood levels of endovanilloids and endocannabinoids were increased in endotoxemic mice. CONCLUSIONS: OLDA has strong anti-inflammatory actions in mice with endotoxemia or S. aureus pneumonia. Prior studies focused on the role of peripheral nervous system TRPV1 in modulating inflammation and pneumonia. Our results suggest that TRPV1-expressing central nervous system neurons also regulate inflammatory responses to endotoxemia and infection. Our study reveals a neuro-immune reflex that during acute inflammation is engaged proximally by OLDA acting on neuronal TRPV1, and through a multicellular network that requires circulating monocytes/macrophages, leads to the systemic production of IL-10.

Activation of CB1R Promotes Lipopolysaccharide-Induced IL-10 Secretion by Monocytic Myeloid-Derived Suppressive Cells and Reduces Acute Inflammation and Organ Injury.

Cannabis sativa and its principal components, Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol, are increasingly being used to treat a variety of medical problems, including inflammatory conditions. Although studies suggest that the endocannabinoid system has immunomodulatory properties, there remains a paucity of information on the effects of cannabinoids on immunity and on outcomes of infection and injury. We investigated the effects and mechanism(s) of action of cannabinoid receptor agonists, including Δ9-THC, on inflammation and organ injury in endotoxemic mice. Administration of Δ9-THC caused a dramatic early upregulation of plasma IL-10 levels, reduced plasma IL-6 and CCL-2 levels, led to better clinical status, and attenuated organ injury in endotoxemic mice. The anti-inflammatory effects of Δ9-THC in endotoxemic mice were reversed by a cannabinoid receptor type 1 (CB1R) inverse agonist (SR141716), and by clodronate-induced myeloid-cell depletion, but not by genetic invalidation or blockade of other putative Δ9-THC receptors, including cannabinoid receptor type 2, TRPV1, GPR18, GPR55, and GPR119. Although Δ9-THC administration reduced the activation of several spleen immune cell subsets, the anti-inflammatory effects of Δ9-THC were preserved in splenectomized endotoxemic mice. Finally, using IL-10-GFP reporter mice, we showed that blood monocytic myeloid-derived suppressive cells mediate the Δ9-THC-induced early rise in circulating IL-10. These results indicate that Δ9-THC potently induces IL-10, while reducing proinflammatory cytokines, chemokines, and related organ injury in endotoxemic mice via the activation of CB1R. These data have implications for acute and chronic conditions that are driven by dysregulated inflammation, such as sepsis, and raise the possibility that CB1R-signaling may constitute a novel target for inflammatory disorders.

Catecholaminergic Vasopressors Reduce Toll-Like Receptor Agonist-Induced Microvascular Endothelial Cell Permeability But Not Cytokine Production.

OBJECTIVES: Catecholaminergic vasopressors are the cornerstone of circulatory shock management. Nevertheless, catecholamines have problematic side effects, arousing a growing interest in noncatecholaminergic agents such as vasopressin or angiotensin-II. However, their respective effects on sepsis-associated microvascular endothelial dysfunction such as permeability or inflammation remain elusive. We investigated the role of catecholamines and other vasopressors on Toll-like receptor agonists-induced microvascular endothelial permeability and inflammation. SETTING: University research laboratory/cell research. SUBJECTS: Human pulmonary microvascular endothelial cells from multiple donors. INTERVENTION: Confluent monolayers of human pulmonary microvascular endothelial cells were treated with Toll-like receptor agonists (lipopolysaccharide, Poly[I:C], or tripalmitoyl-S-glyceryl cysteine) in the presence or absence of epinephrine, norepinephrine, vasopressin, and angiotensin-II. Permeability was inferred from transendothelial resistance, measured using electrical cell impedance sensing, where decreased transendothelial resistance is consistent with increased permeability. Cell-cell junction molecule expression was assessed via immunofluorescence microscopy and flow cytometry. We quantified cytokines in supernatants of Toll-like receptor agonist-treated human pulmonary microvascular endothelial cells. MEASUREMENTS AND MAIN RESULTS: Epinephrine and norepinephrine both ameliorate lipopolysaccharide, polyinosinic:polycytidylic acid, or tripalmitoyl-S-glyceryl cysteine-induced reductions in transendothelial resistance, a surrogate for endothelial permeability. In contrast, the noncatecholaminergic agents, vasopressin, and angiotensin-II did not affect Toll-like receptor agonists-induced reductions in transendothelial resistance. ß1- and ß2-adrenergic receptor antagonists reduced the effects of the catecholamines on transendothelial resistance, whereas α-adrenergic receptor antagonists did not. We observed that epinephrine and norepinephrine induced actin cytoskeletal rearrangement and normalized the membrane expression of proteins involved with adherens-junctions (vascular endothelial-cadherin) and tight-junctions (zona occludens-1). Despite having a substantial effect on endothelial permeability, epinephrine and norepinephrine did not affect human pulmonary microvascular endothelial cell survival or production of interleukin-8, interleukin-6, or monocyte chemoattractant protein-1 (CCL-2) induced by Toll-like receptor agonists, suggesting that these functions are regulated separately from permeability. CONCLUSIONS: Our findings demonstrate that treatment with epinephrine or norepinephrine strongly reduces endothelial permeability induced by agonists of multiple Toll-like receptors (Toll-like receptor-2, Toll-like receptor-3, Toll-like receptor-4) in vitro. Our studies suggest that both ß1- and ß2-adrenergic receptors mediate the stabilizing effects of epinephrine and norepinephrine on the endothelial barrier.

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.

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.

Mottling score is a strong predictor of 14-day mortality in septic patients whatever vasopressor doses and other tissue perfusion parameters.

BACKGROUND: Mottling score, a tissue perfusion parameter, is correlated with outcome in septic shock patients. However, its predictive value on mortality according to prognostic covariates such as vasopressor dose and other tissue perfusion parameters remains unknown. METHODS: Mottling score and tissue perfusion parameters were recorded at ICU admission (H0), H-6, H 12, and H-24 and used to assess the predictive value of mottling score on 14-day mortality in a development cohort. Results were then validated in an independent cohort of septic shock patients in Brazil. RESULTS: Overall, 259 patients with sepsis or septic shock were included, 14-day mortality was 37%. Factors associated with death were mottling score (OR 2.26 [95% CI, 1.72-2.97]), arterial lactate level (OR 1.29 [1.11-1.5]), and urine output < 0.5 ml/Kg/h (OR 3.03 [1.37-6.69]). The C statistic for the model was 0.90 in the development cohort and 0.76 in the validation cohort. The predictive value of mottling score was not affected by vasopressor doses (p for interaction = 0.33): OR for mottling score ranged from 2.34 [1.10-3.15] in patients without vasopressor to 3.84 [1.98-7.43] in patients infused with high doses of vasopressor (> 0.8 µg/kg/min). There was no difference in the effect of mottling score on mortality according to mean arterial pressure, heart rate, cardiac index, and urine output, but we found a significant interaction between arterial lactate level and mottling score (p = 0.04). The predictive value of the mottling score remains significant when using the recent SEPSIS-3 definition of septic shock. Finally, a decrease of mottling score during resuscitation was significantly associated with better outcome after adjustment on SOFA score (p = 0.001). CONCLUSIONS: Our results support the high prognostic value of mottling score for 14-day mortality in septic patients, whatever vasopressor dosage and other perfusion parameters. Mottling score variations during resuscitation are also predictive of mortality.

Exploring the microvascular impact of red blood cell transfusion in intensive care unit patients.

BACKGROUND: Red blood cell (RBC) transfusion is a common treatment for hospitalized patients. However, the effects of RBC transfusion on microvascular function remain controversial. METHODS: In a medical ICU in a tertiary teaching hospital, we prospectively included anemic patients requiring RBC transfusion. Skin microvascular reactivity was measured before and 30 min after RBC transfusion. Plasma was collected to analyze intravascular hemolysis and draw the lipidomic and cytokine profiles. RESULTS: In a cohort of 59 patients, the median age was 66 [55-81] years and SAPS II was 38 [24-48]. After RBC transfusion, endothelium-dependent microvascular reactivity improved in 35 (59%) patients, but worsened in 24 others (41%). Comparing clinical and biological markers revealed that baseline blood leucokyte counts distinguished improving from worsening patients (10.3 [5.7; 19.7] vs. 4.6 [2.1; 7.3] × 109/L; p = 0.001) and correlated with variations of microvascular reactivity (r = 0.36, p = 0.005). Blood platelet count was also higher in improving patients (200 [97; 280] vs 160 [40; 199] × 103/mL, p = 0.03) but did not correlate with variations of microvascular reactivity. We observed no intravascular hemolysis (HbCO, heme, bilirubin, LDH), but recorded a significant increase in RBC microparticle levels specific to improving patients after transfusion (292 [108; 531] vs. 53 [34; 99] MP/µL; p = 0.03). The improvement in microvascular dilation was positively correlated with RBC microparticle levels (R = 0.83, p < 0.001) and conversion of arachidonic acid into vasodilating eicosanoids. CONCLUSIONS: Patients displaying an improved microvascular reactivity after RBC transfusion had high blood leukocyte counts, increased RBC microparticle formation, and enhanced metabolism of arachidonic acid into vasodilating lipids. Our data suggested a contribution of recipient leukocytes to the vascular impact of RBC transfusion.

Reversible Microvascular Hyporeactivity to Acetylcholine During Diabetic Ketoacidosis.

OBJECTIVES: Metabolic acidosis is commonly observed in critically ill patients. Experimental studies suggested that acidosis by itself could impair vascular function, but this has been poorly investigated in human. DESIGN: Prospective observational study. SETTING: Medical ICU in a tertiary teaching hospital. PATIENTS: To assess the relationship between metabolic acidosis severity and microvascular reactivity, we included adult diabetic patients admitted in ICU for ketoacidosis. Microvascular response to acetylcholine iontophoresis was measured at admission (baseline) and after correction of metabolic acidosis (24 hr). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Thirty-nine patients with diabetic ketoacidosis were included (68% male), with a median age of 43 (31-57) years. At admission, microvascular reactivity negatively correlated with acidosis severity (R = -0.53; p < 0.001). Microvascular response was strongly depressed at pH less than 7.20 (area under the curve, 1,779 [740-3,079] vs 12,944 [4,874-21,596] at pH > 7.20; p < 0.0001). In addition, acidosis severity was significantly correlated with capillary refill time (R = 0.50; p = 0.02). At H24, after rehydration and insulin infusion, clinical and biological disorders were fully corrected. After acidosis correction, microvascular reactivity increased more in patients with severe baseline acidosis (pH < 7.20) than in those with mild baseline acidosis (area under the curve, +453% [213%-1,470%] vs +121% [79%-312%]; p < 0.01). CONCLUSIONS: We identified an alteration of microvascular reactivity during metabolic acidosis in critically ill patients with diabetic ketoacidosis. Microvascular hyporeactivity recovered after acidosis correction.

Marked regional endothelial dysfunction in mottled skin area in patients with severe infections.

BACKGROUND: Mottling around the knee, reflecting a reduced skin blood flow, is predictive of mortality in patients with septic shock. However, the causative pathophysiology of mottling remains unknown. We hypothesized that the cutaneous hypoperfusion observed in the mottled area is related to regional endothelial dysfunction. METHODS: This was a prospective, observational study in a medical ICU in a tertiary teaching hospital. Consecutive adult patients with sepsis admitted to ICU were included. After resuscitation, endothelium-dependent vasodilation in the skin circulation was measured before and after iontophoresis of acetylcholine (Ach) in the forearm and the knee area. We analyzed the patterns of induced vasodilatation according to the presence or absence of mottling and vital status at 14 days. RESULTS: We evaluated 37 septic patients, including 11 without and 26 with septic shock. Overall 14-day mortality was 22%. Ten patients had mottling around the knee (10/37, 27%). In the knee area, the increased skin blood flow following iontophoresis of Ach was lower in patients with mottled skin as compared to patients without mottled skin (area under curve (AUC) 3280 (2643-6440) vs. 7980 (4233-19,707), both P < 0.05). In the forearm area, the increased skin blood flow following iontophoresis of Ach was similar in patients with and without mottled skin. Among patients with septic shock, the increased skin blood flow following iontophoresis of Ach in the knee area was significantly lower in non-survivors as compared to survivors at 14 days (AUC 3256 (2600-4426) vs. 7704 (4539-15,011), P < 0.01). In patients with septic shock, the increased skin blood flow in the forearm area following iontophoresis of Ach was similar in survivors and non-survivors at 14 days. CONCLUSION: Mottling is associated with regional endothelial dysfunction in patients with septic shock. Endothelial dysfunction in the knee skin area was more pronounced in non-survivors than in survivors.

Natural regulatory T cells limit angiotensin II-induced aneurysm formation and rupture in mice.

OBJECTIVE: Abdominal aortic aneurysm is an inflammatory disease leading to destructive vascular remodeling and ultimately to lethal aortic rupture. Despite its frequent association with atherosclerosis, compelling studies have shown striking differences and potentially opposite roles of T-cell helper responses in aneurysm as compared with atherosclerosis, casting doubt on the relevance and suitability of T-cell-targeted therapies in this context. APPROACH AND RESULTS: Here, we show that selective depletion of T regulatory (Treg) cells using a CD25-specific monoclonal antibody significantly enhances the susceptibility of C57Bl/6 mice to angiotensin II-induced abdominal aortic aneurysm and promotes aortic rupture (n=25-44 mice/group). Similar results are observed in angiotensin II-treated Cd80(-/-)/Cd86(-/-) or Cd28(-/-) mice with impaired Treg cell homeostasis (n=18-23 mice/group). Treg cell depletion is associated with increased immune cell activation and a blunted interleukin (IL)-10 anti-inflammatory response, suggesting an immunoinflammatory imbalance. Interestingly, Il-10(-/-) mice (n=20 mice/group) show increased susceptibility to angiotensin II-induced abdominal aortic aneurysm and aortic rupture and are insensitive to Treg cell depletion. Finally, reconstitution of Cd28(-/-) Treg-deficient mice with Treg cells (n=22 mice/group) restores a balance in the immunoinflammatory response, rescues the animals from increased susceptibility to aneurysm, and prevents aortic dissection. CONCLUSIONS: These results identify a critical role for Treg cells and IL-10 in the control of aneurysm formation and its progression to rupture and suggest that therapies targeting Treg responses may be most suited to treat aneurysmal disease.

Group X secreted phospholipase A2 limits the development of atherosclerosis in LDL receptor-null mice.

OBJECTIVE: Several secreted phospholipases A2 (sPLA2s), including group IIA, III, V, and X, have been linked to the development of atherosclerosis, which led to the clinical testing of A-002 (varespladib), a broad sPLA2 inhibitor for the treatment of coronary artery disease. Group X sPLA2 (PLA2G10) has the most potent hydrolyzing activity toward phosphatidylcholine and is believed to play a proatherogenic role. METHODS AND RESULTS: Here, we show that Ldlr(-/-) mice reconstituted with bone marrow from mouse group X-deficient mice (Pla2g10(-/-)) unexpectedly display a doubling of plaque size compared with Pla2g10(+/+) chimeric mice. Macrophages of Pla2g10(-/-) mice are more susceptible to apoptosis in vitro, which is associated with a 4-fold increase of plaque necrotic core in vivo. In addition, chimeric Pla2g10(-/-) mice show exaggerated T lymphocyte (Th)1 immune response, associated with enhanced T-cell infiltration in atherosclerotic plaques. Interestingly, overexpression of human PLA2G10 in murine bone marrow cells leads to significant reduction of Th1 response and to 50% reduction of lesion size. CONCLUSIONS: PLA2G10 expression in bone marrow cells controls a proatherogenic Th1 response and limits the development of atherosclerosis. The results may provide an explanation for the recently reported inefficacy of A-002 (varespladib) to treat patients with coronary artery disease. Indeed, A-002 is a nonselective sPLA2 inhibitor that inhibits both proatherogenic (groups IIA and V) and antiatherogenic (group X) sPLA2s. Our results suggest that selective targeting of individual sPLA2 enzymes may be a better strategy to treat cardiovascular diseases.

Aortic valve replacement with the perceval S bioprosthesis: single-center experience in 143 patients.

BACKGROUND AND AIM OF THE STUDY: Aortic stenosis (AS) is the most frequent heart valve disease in western countries, and its prevalence increases with age. Sutureless valves have recently become available that allow the surgical procedures to be shortened. The study aim was to assess clinical outcome after sutureless aortic valve replacement (SAVR) performed with the Perceval S bioprosthesis at the authors' institution. METHODS: Between June 2007 and November 2011, a total of 143 patients (78 females, 65 males; mean age 79.4 +/- 5.9 years) was prospectively enrolled and followed at the authors' center. The median preoperative logistic EuroSCORE was 12.04 +/- 10.7. Preoperatively, 58.8% of patients were in NYHA class III or IV, and the mean gradient and effective orifice area (EOA) were 38.8 +/- 17 mmHg and 0.76 +/- 0.24 cm2, respectively. Isolated SAVR was performed in 95 patients (66.4%), while associated procedures were necessary in 48 patients (33.6%). The follow up was 100% complete (mean 13.4 +/- 11.6 months; range: 0-5 years; total cumulative follow up 155 patient-years). RESULTS: The procedural success rate was 99.3%. The mean cross-clamp and cardiopulmonary bypass times were 32.0 +/- 14.9 min and 44.7 +/- 18.6 min, respectively. In-hospital mortality was 4.9% (n=7). Pacemaker implantation was required in seven patients (4.9%). Survival at five years was 85.5%. Reoperation was necessary in seven patients (4.9%); early reoperations were due to paravalvular leak (n = 3; 2.0%) and intra-prosthetic regurgitation (n=3; 2.0%). One late reoperation (at 29 months) was required, due to fibrous pannus overgrowth. One late endocarditis (0.7%) occurred at 26 months and was medically treated. No structural valve deterioration occurred during the follow up. At 12 months, 94.4% of survivors were in NYHA class I-II, and the mean pressure gradient and EOA were 9.0 +/- 3.4 mmHg and 1.60 +/- 0.3 cm2, respectively. CONCLUSION: The Perceval S valve appears to be a safe option for SAVR, though further follow up is needed to evaluate the long-term outcome with this bioprosthesis.