Intensive care unit (ICU) survivors have reduced long-term survival compared to the general population. Identifying parameters at ICU discharge that are associated with poor long-term outcomes may prove useful in targeting an at-risk population. The main objective of the study was to identify clinical and biological determinants of death in the year following ICU discharge. FROG-ICU was a prospective, observational, multicenter cohort study of ICU survivors followed 1 year after discharge, including 21 medical, surgical or mixed ICUs in France and Belgium. All consecutive patients admitted to intensive care with a requirement for invasive mechanical ventilation and/or vasoactive drug support for more than 24 h following ICU admission and discharged from ICU were included. The main outcome measure was all-cause mortality at 1 year after ICU discharge. Clinical and biological parameters on ICU discharge were measured, including the circulating cardiovascular biomarkers N-terminal pro-B type natriuretic peptide, high-sensitive troponin I, bioactive-adrenomedullin and soluble-ST2. Socioeconomic status was assessed using a validated deprivation index (FDep). Of 1570 patients discharged alive from the ICU, 333 (21%) died over the following year. Multivariable analysis identified age, comorbidity, red blood cell transfusion, ICU length of stay and abnormalities in common clinical factors at the time of ICU discharge (low systolic blood pressure, temperature, total protein, platelet and white cell count) as independent factors associated with 1-year mortality. Elevated biomarkers of cardiac and vascular failure independently associated with 1-year death when they are added to multivariable model, with an almost 3-fold increase in the risk of death when combined (adjusted odds ratio 2.84 (95% confidence interval 1.73–4.65), p < 0.001). The FROG-ICU study identified, at the time of ICU discharge, potentially actionable clinical and biological factors associated with poor long-term outcome after ICU discharge. Those factors may guide discharge planning and directed interventions. ClinicalTrials.gov NCT01367093 . Registered on 6 June 2011.

Mammalian target of rapamycin (mTOR), a serine/threonine kinase, regulates many processes, including cell growth and the immune response. mTOR is also dysregulated in several neurological diseases, such as traumatic brain injury (TBI), stroke, and neurodegenerative disease. However, the role of mTOR in intracerebral hemorrhage (ICH) remains unexplored. The aims of our study were to determine whether inhibiting mTOR signaling could affect the outcome after ICH and to investigate the possible underlying mechanism. A rat ICH model was induced by intracerebral injection of collagenase IV into the striatum, and mTOR activation was inhibited by administration of rapamycin. mTOR signaling activation was determined by western blotting. Neurobehavioral deficit after ICH was determined by a set of modified Neurological Severity Scores (mNSS). The levels of CD4+CD25+Foxp3+ regulatory T cells (Tregs) and cytokines were examined using flow cytometry and ELISA, respectively. Our results demonstrated thatmTOR signaling was activated 30 minutes and returned to its basal level 1 day after ICH. Increased p-mTOR, which mean that mTOR signaling was activated, was predominantly located around the hematoma. Rapamycin treatment significantly improved the neurobehavioral deficit after ICH, increased the number of Tregs, increased levels of interleukin-10 and transforming growth factor-β and reduced interferon-γ both in peripheral blood and brain. Our study suggests that mTOR improves ICH outcome and modulates immune response after ICH.

The immune system, particularly T lymphocytes and cytokines, has been implicated in the progression of brain injury after intracerebral hemorrhage (ICH). Although studies have shown that transplanted neural stem cells (NSCs) protect the central nervous system (CNS) from inflammatory damage, their effects on subpopulations of T lymphocytes and their corresponding cytokines are largely unexplored. Here, rats were subjected to ICH and NSCs were intracerebrally injected at 3 h after ICH. The profiles of subpopulations of T cells in the brain and peripheral blood were analyzed by flow cytometry. We found that regulatory T (Treg) cells in the brain and peripheral blood were increased, but γδT cells (gamma delta T cells) were decreased, along with increased anti-inflammatory cytokines (IL-4, IL-10 and TGF-β) and decreased pro-inflammatory cytokines (IL-6, and IFN-γ), compared to the vehicle-treated control. Our data suggest that transplanted NSCs protect brain injury after ICH via modulation of Treg and γδT cell infiltration and anti- and pro-inflammatory cytokine release.

Background and Purpose: Intracerebral hemorrhage (ICH) is a devastating subtype of stroke with high mortality and disability. Inflammatory response promotes secondary brain injury after ICH. TREM (triggering receptor expressed on myeloid cells)-1 is a key regulator of inflammation. The aim of this study was to evaluate the role of TREM-1 in neuroinflammatory response after ICH in mice. Methods: CD1 mice (n=275) were used in this study. Mice were subjected to ICH by autologous blood injection. TREM-1 knockout CRISPR was administered intracerebroventricularly to evaluate the role of TREM-1 after ICH. A selective TREM-1 inhibitor, LP17, was administered intranasally 2 hours after ICH. To elucidate TREM-1 signaling pathway, CARD9 (caspase recruitment domain family member 9) activation CRISPR was administered with LP17 and TREM-1 activating anti-mouse TREM-1 monoclonal antibody (mAb) was administered with Rottlerin, a specific PKC (protein kinase C) δ inhibitor. Lastly, to evaluate the role of HMGB1 (high-mobility group box 1) in TREM-1 mediated microglia activation, glycyrrhizin, an inhibitor of HMBG1 was administered with TREM-1 activating mAb. Neurobehavioral test, brain water content, Western blot, immunofluorescence staining, and coimmunoprecipitation was performed. Results: TREM-1 knockout reduced ICH-induced neurobehavioral deficits and neuroinflammatory response. The temporal expression of HMGB1, TREM-1, PKC δ, and CARD9 increased after ICH. TREM-1 was expressed on microglia. Intranasal administration of LP17 significantly decreased brain edema and improved neurobehavioral outcomes at 24 and 72 hours after ICH. LP17 promoted M2 microglia polarization and reduced proinflammatory cytokines after ICH, which was reversed with CARD9 activation CRISPR. TREM-1 mAb increased neurobehavior deficits, proinflammatory cytokines, and reduced M2 microglia after ICH, which was reversed with Rottlerin. HMBG1 interaction with TREM-1 increased after ICH, and glycyrrhizin reduced neuroinflammation and promoted M2 microglia which was reversed with TREM-1 mAb. Conclusions: This study demonstrated that TREM-1 enhanced neuroinflammation by modulating microglia polarization after ICH, and this regulation was partly mediated via PKC δ/CARD9 signaling pathway and increased HMGB1 activation of TREM-1.