Detrimental arterial inflammatory effect of microparticles circulating in preeclamptic women: ex vivo evaluation in human arteries

International audienceElevated plasmatic levels of lympho-monocyte and platelet microparticles (MPs) have been reported in preeclampsia. Previous studies suggest that MPs could participate in preeclampsia vascular impairment. In this study, we investigated the ex vivo vascular effects of MPs from preeclamptic women on arteries from normotensive pregnant women. Omental arteries were collected from normal pregnant women undergoing cesarean section and incubated during 24 h with MPs from normal pregnant or preeclamptic women. Vascular contraction to serotonin and phenylephrine was studied on a wire myograph with or without pharmacological selective inhibitors of inducible nitric oxide synthase (iNOS) and/or cyclo-oxygenase-2 (COX-2). Expression of iNOS, COX-2, and NF-κB and production of superoxide anion and 8-isoprostane were also assessed by immunohistological or biochemical staining and/or Western blot or ELISA assay, respectively. Microparticles from preeclamptic women, but not those from normal pregnant women, induced hyporeactivity to vasocontracturant agonists in omental arteries. Selective inhibitor of iNOS partially restored this arterial contraction, suggesting that nitric oxide (NO) is involved in vascular contractility alteration. Conversely, COX-2 induced 8-isoprostane release, a vasoconstricting metabolite modulating the agonist-induced contraction. COX-2 selective inhibitor almost abolished the arterial contraction in the same vessels. Interestingly, the association of iNOS and COX-2 selective inhibitors restored the contraction to control levels. Moreover, iNOS, COX-2, and NF-κB expressions are upregulated and superoxide anion levels increased in vessels incubated with MPs from preeclamptic women. In conclusion, circulating MPs from preeclamptic women induce vascular inflammation and enhance oxidative stress. These results suggest a possible role of MPs during preeclampsia-induced arterial dysfunction

Dexamethasone and Recombinant Human Activated Protein C Improve Myocardial Function and Efficiency During Experimental Septic Shock

International audienceCorticosteroids have been shown to reduce short-term mortality during septic shock and therefore recommended in the most severe patients as adjuvant therapy. Until recently, recombinant human activated protein C (APC) was also considered in the management of more severe cases. As myocardial depression has long been recognized as a manifestation of organ dysfunction during septic shock, we examined whether corticosteroids (dexamethasone, 150 µg/kg per hour) and/or APC (33 µg/kg per hour) treatments improve sepsis-induced cardiac dysfunction during cecal ligature and puncture-induced septic shock in Wistar rats. All rats received intravenous saline resuscitation (10 mL/kg per hour) and antibiotics. Eighteen hours after surgery, anesthesia was performed (isoflurane), and myocardial function was assessed using a conductance catheter introduced into the left ventricle. Rats were then killed; blood and heart were harvested for biological analysis, including radical oxygen species determination. Cecal ligature and puncture induced hypotension, depression of myocardial systolic performance (demonstrated by significant decreases in dP/dtmax [first derivative of maximal developed pressure during isovolumetric contraction], end-systolic pressure-volume relationship, and preload recruitable stroke work) and alteration of diastolic function (dP/dtmin [first derivative of minimal developed pressure during isovolumetric relaxation]), whereas dexamethasone, APC, and their combination thereof allowed correction of hemodynamic disorders and improved myocardial mechanical efficiency. Cecal ligature and puncture was associated with higher levels of nitric oxide and superoxide anion (O2) in heart (electron paramagnetic resonance studies) and consequently peroxynitrite. Dexamethasone and APC also improved cardiac dysfunction by downregulating the inducible nitric oxide synthase pathway and reducing myocardial oxidative stress

Is Thrombocytopenia an Early Prognostic Marker in Septic Shock?

IF 7.442International audienceObjectives: To assess whether early thrombocytopenia during septic shock is associated with an increased risk of death at day 28 and to identify risk factors associated with a low platelet count.Design: Prospective, multicenter, observational cohort study.Setting: Fourteen ICUs from 10 French university teaching and nonacademic hospitals.Patients: Consecutive adult patients with septic shock admitted between November 2009 and September 2011 were eligible.Intervention: None.Measurements and Main Results: Of the 1,495 eligible patients, 1,486 (99.4%) were included. Simplified Acute Physiology Score II score of greater than or equal to 56, immunosuppression, age of more than 65 years, cirrhosis, bacteremia (p 0.001 for each), and urinary sepsis (p = 0.005) were globally associated with an increased risk of thrombocytopenia within the first 24 hours following the onset of septic shock. Survival at day 28 estimated by the Kaplan-Meier method was lower in patients with thrombocytopenia and decreased with thrombocytopenia severity. By multivariate Cox regression, a platelet count of less than or equal to 100,000/mm(3) was independently associated with a significantly increased risk of death within the 28 days following septic shock onset. The risk of death increased with the severity of thrombocytopenia (hazard ratio, 1.65; 95% CI, 1.31-2.08 for a platelet count below 50,000/mm(3) vs > 150,000/mm(3); p < 0.0001).Conclusions: This is the first study to investigate thrombocytopenia within the first 24 hours of septic shock onset as a prognostic marker of survival at day 28 in a large cohort of ICU patients. Measuring platelet count is inexpensive and easily feasible for the physician in routine practice, and thus, it could represent an easy alert system among patients in septic shock

"Immunonutrition" Has Failed to Improve Peritonitis-Induced Septic Shock in Rodents.

BACKGROUND:Immunonutrition in sepsis, including n-3 poly-unsaturated fatty acids (PUFAs) or L-arginine supplementation, is a controversial issue that has yielded a great number of studies for the last thirty-five years, and the conclusions regarding the quantity and quality of this support in patients are deceiving. The aim of the present experimental study is to investigate the effects of a pretreatment with enteral nutrition enriched with n-3 PUFAs or L-arginine on vascular dysfunctions, inflammation and oxidative stress during septic shock in rats. DESIGN:Rats were fed with enteral Peptamen® HN (HN group), Peptamen® AF containing n-3 PUFAs (AF group) or Peptamen® AF enriched with L-arginine (AFA group). On day 4, peritonitis by cecal ligation and puncture (CLP) was performed. Rats were resuscitated (H18) once septic shock was established. After a 4-hour resuscitation, vessels and organs were harvested to assess inflammation, superoxide anion, nitric oxide and prostacyclin levels. Ex-vivo vascular reactivity was also performed. RESULTS:Compared to CLP-AF or CLP-HN groups, 47.6% of CLP-AFA rats died before the beginning of hemodynamic measurements (vs. 8.0% and 20.0% respectively, p<0.05). AF and AFA rats required significantly increased norepinephrine infusion rates to reach the mean arterial pressure objective, compared to CLP-HN rats. Both CLP-AF and CLP-AFA reduced mesenteric resistance arterial contractility, decreased vascular oxidative stress, but increased NF-κB (0.40±0.15 in CLP-AF and 0.69±0.06 in CLP-AFA vs. 0.09±0.03 in SHAM rats and 0.30±0.06 in CLP-HN, ß-actin ratio, p<0.05) and pIκB expression (0.60±0.03 in CLP-AF and 0.94±0.15 in CLP-AFA vs. 0.04±0.01 in SHAM rats and 0.56±0.07 in CLP-HN, ß-actin ratio, p<0.05), nitric oxide and prostacyclin production in septic rats. CONCLUSIONS:Although n-3 PUFAs or L-arginine supplementation exhibited an antioxidant effect, it worsened the septic shock-induced vascular dysfunction. Furthermore, mortality was higher after L-arginine supplementation

Early Detection of Disseminated Intravascular Coagulation During Septic Shock: A Multicenter Prospective Study.

IF 7.442International audienceOBJECTIVES:Inadequate stratification of septic shock patients may result in inappropriate treatment allocation in randomized clinical trials, especially regarding anticoagulant. We previously reported that endothelial-derived microparticles are relevant biomarkers of sepsis-induced disseminated intravascular coagulation. In this validation cohort, we assess microparticles as surrogates of cell activation to improve early disseminated intravascular coagulation diagnosis and patient stratification.DESIGN:Prospective observational study in septic shock patients.SETTINGS:Four medical ICUs in university hospitals.PATIENTS AND METHODS:Two hundred sixty-five patients with septic shock from four ICUs were consecutively enrolled. Disseminated intravascular coagulation was diagnosed according to Japanese Association for Acute Medicine 2006 score. Endothelial- and leukocyte-derived circulating procoagulant microparticles were isolated and quantified by prothrombinase assay at admission, day 3, and day 7.INTERVENTION:None.MEASUREMENTS AND MAIN RESULTS:Two hundred fifty-nine patients were analyzed. Sixty-one had disseminated intravascular coagulation at admission, and 32 developed disseminated intravascular coagulation during the first 24 hours after admission. Multiple logistic regression model confirmed that endothelial cell-derived microparticles were associated with disseminated intravascular coagulation: CD105-microparticles (odds ratio, 2.13) and CD31-microparticles (odds ratio, 0.65) (p 0.60 nM eq. PhtdSer; odds ratio, 1.67; p < 0.01), platelets count (≤ 127 g/L; odds ratio, 0.99; p < 0.01), and prothrombin time (≤ 58%; odds ratio, 0.98; p < 0.05) with disseminated intravascular coagulation. A combining score at admission is predictive of the absence of disseminated intravascular coagulation (area under the curve, 72.9%; specificity, 71.2%; sensitivity, 71.0%, with a negative predictive value of 93.1% and a positive predictive value of 31.0%).CONCLUSIONS:Procoagulant microparticles from endothelial cells and leukocytes reflect a vascular injury during sepsis-induced disseminated intravascular coagulation that precedes obvious activation of coagulation. A combination of prothrombin time, endothelium-derived CD105-microparticles, and platelet count at admission could predict the absence of disseminated intravascular coagulation and allow a better stratification in future randomized clinical trials

Protocol design.

<p>Gastrostomy was performed on day 1 (D1). Rats were then fed with different enteral nutrition products (Peptamen^® HN–“HN”, Peptamen^® AF–“AF”, Peptamen^® AF enriched with arginine–“AFA”) for three days (72 hours) before undergoing peritonitis by cecal ligation and puncture (CLP) or SHAM operation on day 4. Septic shock developed within 18 hours after surgery in the CLP group. Therefore from H18 to H22 after SHAM/CLP surgery, rats were resuscitated using fluid challenge and norepinephrine to target a mean arterial pressure (MAP) value over 100 mmHg. Blood, organs and vessels were collected at the end of the monitoring.</p

(A-F): A) Cumulative norepinephrine dose needed to reach the mean arterial pressure (MAP) objective in SHAM and septic rats treated with different enteral nutrition formulations: Peptamen^® AF (AF), Peptamen^® HN (HN), Peptamen^® AF enriched with arginine (AFA); * p<0.05 <i>vs</i>. SHAM rats, # p<0.05 <i>vs</i>. CLP-HN rats. n = 5 for SHAM group and n = 12 for CLP-HN, CLP-AF and CLP-AFA groups. B) <i>Ex-vivo</i> vascular contractility of mesenteric resistance arteries of SHAM and septic rats in response to 5-HT, * p<0.05 <i>vs</i>. SHAM rats. n = 5 for SHAM group and n = 12 for CLP-HN, CLP-AF and CLP-AFA groups. C-F) Effect of the specific iNOS inhibitor (1400W) and the specific COX-2 inhibitor (NS-398) on 5-HT-dependent contraction in mesenteric resistance arteries in each different group of rats (C = SHAM rats, D = CLP-AF rats, E = CLP-AFA rats, F = CLP-HN rats).

<p>§ p<0.05 vs. without inhibitor. Results are expressed as mean ± SD. n = 5 for SHAM group and n = 12 for CLP-HN, CLP-AF and CLP-AFA groups.</p

(A-D): A-B) NF-κB p65/RelA expression and pIκB-α content in mesenteric resistance artery (MRA) tissue homogenates from septic and SHAM rats treated with different enteral nutrition formulations: Peptamen^® AF (AF), Peptamen^® HN (HN), Peptamen^® AF enriched arginine (AFA).

<p>Densitometry images are representative of six separate blots and mean ± SD densitometry values are expressed in arbitrary units (A.U.) relative to β-tubulin content. Different enteral nutrition formulations were as follows: Peptamen^® AF (AF), Peptamen^® HN (HN), Peptamen^® AF enriched arginine (AFA). * p<0.05 vs. all the other groups, # p<0.05 vs. SHAM rats, & p<0.05 vs. CLP-AF rats, $ <0.05 vs. CLP-HN rats. n = 5 for SHAM group and n = 12 for CLP-HN, CLP-AF and CLP-AFA groups.</p