Sébastien Gibot

Probiotics in the critically ill patient: a double blind, randomized, placebo-controlled trial

PurposeProbiotics have been shown to be able to restore a non-pathogenic digestive flora, to prevent digestive colonization by pathogenic bacteria, and to modulate immunity. The aim of this study was to assess the effects of prophylactic probiotic administration in patients ventilated for up to 2xa0days.MethodsThis study was performed as a double-blind, concealed randomized, placebo-controlled trial in a French medical intensive care unit (ICU). Adult patients mechanically ventilated for a period of more than 48xa0h received enterally administered probiotics (Ergyphilus®, 2xa0×xa01010 lactic acid bacteria, mostly Lactobacillus rhamnosus GG, once a day) or placebo until successful weaning.ResultsA total of 167 patients were included. The two groups were comparable at baseline. The 28-day mortality rates were not different in the probiotic (25.3%) and placebo groups (23.7%). Mortality rates in ICU and at 90xa0days were also unaffected by the treatment. The incidence of ICU-acquired infections did not differ significantly except for that of catheter-related bloodstream infections that was lowered by probiotics. On a prespecified subgroup analysis, we found a reduction of the 28-day mortality among severe sepsis patients (total nxa0=xa0101) treated with probiotics (nxa0=xa052) with an odds ratio (OR) for death at 0.38 (95% CI 0.16–0.93, pxa0=xa00.035). By contrast, probiotics were associated with a higher mortality rate in non-severe sepsis patients (OR 3.09, 95% CI 0.87–11.01, pxa0=xa00.08).ConclusionsAlthough numerous uncertainties remain (type and the number of strains to use, delay and length of administration), and despite an acceptable safety profile, the daily prophylactic administration of probiotics cannot be encouraged in the critically ill patient.

Growth arrest-specific protein 6 plasma concentrations during septic shock

IntroductionThe product of growth arrest-specific gene 6 (Gas6) is a vitamin K dependent protein that is secreted by leucocytes and endothelial cells in response to injury and participates in cell survival, proliferation, migration and adhesion. Our purpose was to investigate plasma Gas6 concentration and its relation to organ dysfunction in patients with septic shock.MethodsForty-five patients with septic shock admitted to a medical adult intensive care unit were enrolled. Plasma Gas6 concentration was determined using enzyme-linked immunosorbent assay at days 1, 3, 7 and 14.ResultsThe median (interquartile range) Gas6 concentration was 51 (5 to 95) pg/ml at admission. A positive correlation (Spearman rank-order coefficient [rs] = 0.37, P = 0.01) was found between Gas6 level and Sepsis-related Organ Failure Assessment score. Patients requiring renal support had higher Gas6 concentration that those without need for haemofiltration (76.5 [52 to 164] pg/ml versus 10.5 [1.5 to 80.5] pg/ml; P = 0.04). Moreover, there was a positive correlation between Gas6 and aspartate transaminase (rs = 0.42, P = 0.006) and between Gas6 and prothrombin time (rs = 0.45, P = 0.02). Although there was a progressive decline in Gas6 concentration in survivors (analysis of variance, P = 0.01), nonsurvivors exhibited persistently elevated Gas6. However, the two populations diverged only after day 7 (P = 0.04).ConclusionPlasma concentrations of Gas6 correlate with disease severity, especially with renal and hepatic dysfunction, in septic shock.

Expression Profile and Function of Triggering Receptor Expressed on Myeloid Cells-1 during Melioidosis

BACKGROUNDnTriggering receptor expressed on myeloid cells-1 (TREM-1) amplifies Toll-like receptor-initiated responses against pathogens. We aimed to characterize TREM-1 expression and function during sepsis caused by Burkholderia pseudomallei (melioidosis).nnnMETHODSnTREM-1 expression was determined on leukocytes and plasma from 34 patients with melioidosis and 32 controls and in mice with experimentally induced melioidosis. Responsiveness toward B. pseudomallei of TREM-1(+) and TREM-1(-) leukocytes was tested in vitro. TREM-1 function was inhibited in mice by a synthetic peptide mimicking the ectodomain of this receptor.nnnRESULTSnPatients demonstrated increased soluble (s) TREM-1 plasma levels and TREM-1 surface expression on monocytes but not granulocytes. Similarly, mice inoculated with B. pseudomallei displayed a gradual rise in sTREM-1 level and an increase in blood monocyte but not granulocyte TREM-1 expression. At the primary infection site, however, granulocyte TREM-1 expression was enhanced, and the rise in sTREM-1 level occurred earlier. Additionally, purified human TREM-1(-) granulocytes showed reduced responsiveness to B. pseudomallei relative to TREM-1(+)granulocytes, a difference not detected for TREM-1(-) and TREM-1(+) monocytes. Treatment with a peptide mimicking a conserved domain of sTREM-1 partially protected mice from B. pseudomallei-induced lethality.nnnCONCLUSIONSnDuring melioidosis, TREM-1 expression is differentially regulated on granulocytes and monocytes; measurement of TREM-1 expression on blood granulocytes may not provide adequate information on granulocyte TREM-1 expression at the infection site. TREM-1 may be a therapeutic target in melioidosis.

Plasma soluble triggering receptor expressed on myeloid cells-1 in Crohn's disease

BACKGROUNDnNo definite conclusions can be drawn from available data on the accuracy of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) to assess disease activity in Crohns disease.nnnAIMSnPlasma sTREM-1 levels were correlated with disease activity markers in Crohns disease.nnnMETHODSn191 consecutive patients from a single referral centre (Nancy IBD cohort) were prospectively enrolled between June 1, 2005 and December 12, 2008. Plasma sTREM-1 levels were also assessed amongst 20 healthy controls.nnnRESULTSnThe sTREM-1 was detectable in 87 Crohns disease patients (46%). Plasma sTREM-1 level was higher in Crohns disease patients (interquartile range, 0-356) than in healthy controls (interquartile range, 0-15.1; P=0.01). It was neither correlated with Crohns disease activity index (r=0.05, P=0.56), C-reactive protein (r=0.06, P=0.53), nor with albumin (r=-0.041, P=0.66). Crohns disease activity index, C-reactive protein and albumin median levels were similar between patients with positive sTREM-1 levels and those with undetectable sTREM-1 levels. Azathioprine (P=0.06), infliximab (P=0.68) and methotrexate (P=0.56) did not influence sTREM-1 levels.nnnCONCLUSIONnPlasma sTREM-1 does not appear to be an accurate marker of disease activity in Crohns disease and cannot be recommended for assessing disease activity in these patients.

Concise Review: Mesenchymal Stromal/Stem Cells: A New Treatment for Sepsis and Septic Shock?

Sepsis and septic shock are the leading cause of admission and mortality in non‐coronary intensive care units. Currently, however, no specific treatments are available for this syndrome. Due to the failure of conventional treatments in recent years, research is focusing on innovative therapeutic agents, including cell therapy. One particular type of cell, mesenchymal stromal/stem cells (MSCs), has raised hopes for the treatment of sepsis. Indeed, their immunomodulatory properties, antimicrobial activity and capacity of protection against organ failure confer MSCs with a major advantage to treat the immune and inflammatory dysfunctions associated with sepsis and septic shock. After a brief description of the pathophysiology of sepsis and septic shock, the latest advances in the use of MSCs to treat sepsis will be presented. Stem Cells 2017;35:2331–2339

18F-fluorodeoxyglucose positron emission tomography combined with whole-body computed tomographic angiography in critically ill patients with suspected severe sepsis with no definite diagnosis

PurposeTimely identification of septic foci is critical in patients with severe sepsis or septic shock of unknown origin. This prospective pilot study aimed to assess 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), combined with whole-body computed tomographic angiography (CTA), in patients with suspected severe sepsis and for whom the prior diagnostic workup had been inconclusive.MethodsPatients hospitalized in an intensive care unit with a suspected severe sepsis but no definite diagnosis after 48xa0h of extensive investigations were prospectively included and referred for a whole body FDG-PET/CTA. Results from FDG-PET/CTA were assessed according to the final diagnosis obtained after follow-up and additional diagnostic workup.ResultsSeventeen patients were prospectively included, all on mechanical ventilation and 14 under vasopressor drugs. The FDG-PET/CTA exam 1) was responsible for only one desaturation and one hypotension, both quickly reversible under treatment; 2) led to suspect 16 infectious sites among which 13 (81xa0%) could be confirmed by further diagnostic procedures; and 3) triggered beneficial changes in the medical management of 12 of the 17 study patients (71xa0%). The FDG-PET/CTA images showed a single or predominant infectious focus in two cases where CTA was negative and in three cases where CTA exhibited multiple possible foci.ConclusionWhole-body FDG-PET/CTA appears to be feasible, relatively safe, and provides reliable and useful information, when prospectively planned in patients with suspected severe sepsis and for whom prior diagnostic workup had been inconclusive. The FDG-PET images are particularly helpful when CTA exhibits no or multiple possible sites.

Mesenchymal Stromal/Stem Cells: A New Treatment For Sepsis And Septic Shock?

Sepsis and septic shock are the leading cause of admission and mortality in non‐coronary intensive care units. Currently, however, no specific treatments are available for this syndrome. Due to the failure of conventional treatments in recent years, research is focusing on innovative therapeutic agents, including cell therapy. One particular type of cell, mesenchymal stromal/stem cells (MSCs), has raised hopes for the treatment of sepsis. Indeed, their immunomodulatory properties, antimicrobial activity and capacity of protection against organ failure confer MSCs with a major advantage to treat the immune and inflammatory dysfunctions associated with sepsis and septic shock. After a brief description of the pathophysiology of sepsis and septic shock, the latest advances in the use of MSCs to treat sepsis will be presented. Stem Cells 2017;35:2331–2339

Soluble TLT-1 is a naturally occurring TREM-1 inhibitor and protects mice from hyperresponsiveness and death during sepsis

Triggering receptor expressed on myeloid cells-1 (TREM-1) and TREM-like transcript 1 (TLT-1) belong to the TREM family. TREM-1 is expressed on neutrophils and monocytes/macrophages, and plays a crucial role during the onset of sepsis by cooperating with pattern recognition receptors in a synergistic way, thus amplifying the host immune response. TLT-1 is selectively expressed on activated platelets and is known to facilitate platelet aggregation through binding to fibrinogen. Interestingly, TLT-1 null mice displayed higher plasma cytokines concentrations and death rates than WT mice during experimental sepsis. We identified a 17 amino acid peptide derived from the extracellular part of TLT-1, named LR17, which is responsible for TLT-1 anti-inflammatory properties.

Clinical-grade mesenchymal stem cells derived from umbilical cord improve septic shock in pigs

BackgroundSeptic shock is the leading cause of death in intensive care units. The pathophysiological complexity of this syndrome contributes to an absence of specific treatment. Several preclinical studies in murine models of septic shock have shown improvements to organ injury and survival after administration of mesenchymal stem cells (MSCs). To better mimic a clinical approach in humans, we investigated the impact of randomized controlled double-blind administration of clinical-grade umbilical cord-derived MSCs to a relevant pig model of septic shock.MethodsSeptic shock was induced by fecal peritonitis in 12 male domestic pigs. Animals were resuscitated by an experienced intensivist including fluid administration and vasopressors. Four hours after the induction of peritonitis, pigs were randomized to receive intravenous injection of thawed umbilical cord-derived MSCs (UCMSC) (1u2009×u2009106 UCMSCs/kg diluted in 75xa0mL hydroxyethyl starch (HES), (nu2009=u20096) or placebo (HES alone, nu2009=u20096). Researchers were double-blinded to the treatment administered. Hemodynamic parameters were continuously recorded. Gas exchange, acid-base status, organ function, and plasma cytokine concentrations were assessed at regular intervals until 24xa0h after the onset of peritonitis when animals were sacrificed under anesthesia.ResultsPeritonitis induced profound hypotension, hyperlactatemia, and multiple organ failure. These disorders were significantly attenuated when animals were treated with UCMSCs. In particular, cardiovascular failure was attenuated, as attested by a better mean arterial pressure and reduced lactatemia, despite lower norepinephrine requirements. As such, UCMSCs improved survival in this very severe model (60% survival vs. 0% at 24xa0h).ConclusionUCMSCs administration is beneficial in this pig model of polymicrobial septic shock.

0457 : Targeted endothelial Trem-1 deletion protects mice during septic shock

Introduction The Triggering Receptor Expressed on Myeloid cells-1 (TREM-1) amplifies the inflammatory response driven by TLR/NLR engagement. In various models of acute inflammation, septic or not, others and we have shown that the genetic deletion or pharmacologic inhibition of Trem-1 protect animals from hyperresponsiveness and death. In this study we demonstrate that a targeted deletion of Trem-1 on endothelial cells confers protection during septic shock in mice. Methods We generated constitutive Trem-1 -/- KO ( Trem-1 -/- ) as well as endothelium-conditional Trem-1 -/- KO (Endo Trem1 -/- ) mice and submitted them to polymicrobial sepsis through CLP. Organs (BM, spleen, lungs, aorta and mesenteric artery) and blood were harvested at different time points and analyzed for cellular content, gene expression, cytokine/chemokine concentrations, and vasoreactivity. Survival was monitored for 1week. Results Trem-1 -/- and Endo Trem1 -/- mice were equal in size, weight and fertility to littermate controls. Moreover, the composition and abundance of immune cells in blood, BM, spleen, and lungs did not differ between groups. Trem-1 deletion altered inflammatory cells mobilization and recruitment in lungs and spleen and favors the accumulation of reparative cells (Ly6Cl ow monocytes and M2 macrophages) in the lungs. This effect was even more pronounced in Endo Trem1 -/- . Consequently, the activation of many inflammatory genes was reduced in the lungs as well as the concentrations of various cyto/ chemokines (MCP-1, VCAM-1, IL6…). Sepsis induced a profound vascular hyporeactivity in WT mice. This phenomenon was absent in the absence of Trem-1 . Interestingly, in Endo Trem1 -/- while vasoconstriction was still slightly impaired, endothelium-dependent vasodilation remained intact. Finally, survival was improved in the Trem-1 -/- group and even more in the Endo Trem1 -/- group. Conclusion The targeted deletion of endothelial Trem-1 confers protection during septic shock in modulating inflammatory cells mobilization and activation and restoring vasoreactivity. The mechanism by which cellular recruitment is reduced is probably linked to a reduction of chemokines production by endothelial cells. The effect of TREM-1 on vascular tone, while impressive, deserves further investigations. The next step should be to design endothelium specific TREM-1 inhibitors. The author hereby declares no conflict of interest