Early administration of hydrocortisone, vitamin C, and thiamine in adult patients with septic shock: a randomized controlled clinical trial.

BACKGROUND: The combination therapy of hydrocortisone, vitamin C, and thiamine has been proposed as a potential treatment in patients with sepsis and septic shock. However, subsequent trials have reported conflicting results in relation to survival outcomes. Hence, we performed this randomized controlled trial (RCT) to evaluate the efficacy and safety of early combination therapy among adult patients with septic shock. METHODS: This single-center, double-blind RCT enrolled adult patients with diagnosis of septic shock within 12 h from Northern Jiangsu People's Hospital between February 2019 and June 2021. Recruited patients were randomized 1:1 to receive intervention (hydrocortisone 200 mg daily, vitamin C 2 g every 6 h, and thiamine 200 mg every 12 h) or placebo (0.9% saline) for 5 days or until ICU discharge. The primary endpoint was 90-day mortality. The secondary endpoints included mortality at day 28, ICU discharge, and hospital discharge; shock reversal; 72-h Delta SOFA score; ICU-free days, vasopressor-free days, and ventilator support -free days up to day 28; ICU length of stay (LOS) and hospital LOS. RESULTS: Among 426 patients randomized, a total of 408 patients with septic shock were included in the per-protocol (PP) analysis, of which 203 were assigned to the intervention group and 205 to the placebo group. In the PP population, the primary outcome of 90-day mortality was 39.9% (81/203) and 39.0% (80/205) in the intervention and the placebo groups, respectively, and was not significantly different (P = 0.86). There was no significant difference between two groups in 28-day mortality (36.5% vs. 36.1%, P = 0.94) or the ICU mortality (31.5% vs. 28.8%, P = 0.55) and hospital mortality (34.5% vs. 33.2%, P = 0.78). No other secondary outcomes showed significant differences between two groups, including shock reversal, vasopressor-free days, and ICU LOS. Intention-to-treat analysis included all the 426 patients and confirmed these results (all P > 0.05). CONCLUSION: Among adult patients with septic shock, early use of hydrocortisone, vitamin C, and thiamine combination therapy compared with placebo did not confer survival benefits. Trial registration ClinicalTrials.gov: NCT03872011 , registration date: March 12, 2019.

Initial fluid resuscitation (30 mL/kg) in patients with septic shock: More or less?

OBJECTIVES: The 2018 Surviving Sepsis Campaign (SSC) recommends rapid administration of 30 mL/kg crystalloid fluids for hypotension or lactate ≥4 mmol/L in patients with septic shock; however, there is limited evidence to support this recommendation. The purpose of this study was to examine the relationship between initial fluid resuscitation doses and prognosis in patients with septic shock. METHODS: This was a multicenter prospective observational study of adult patients with septic shock who were admitted to four intensive care units (ICUs) in a total of three Jiangsu Province teaching hospitals over a 3-year span from May 8, 2018, to June 15, 2021. Each enrolled patients with septic shock was categorized into the low-volume (below 20 mL/kg fluid), medium-volume (20-30 mL/kg fluid) or high-volume (above 30 mL/kg fluid) fluid group according to the initial infusion dose given for fluid resuscitation. Various demographic attributes and other variables were collected from medical records. Logistic regression and Kaplan-Meier curve analysis were used to determine the relationship between initial fluid resuscitation doses and patient outcomes. MEASUREMENTS AND MAIN RESULTS: A total of 302 patients who presented to the ICU were diagnosed with septic shock. The 28-day mortality was highest in the high-volume group (48.3%) and lowest in the medium-volume group (26.3%, P < 0.05). Patients who completed 30 mL/kg initial fluid resuscitation in the first 1-2 h had the lowest 28-day mortality rate (22.8%, P < 0.05). Logistic regression showed that a medium initial fluid volume dose was an independent protective factor, with the odds ratio (OR) indicating significantly decreased mortality (OR, 0.507; 95% confidence interval, 0.310-0.828; P = 0.007; P < 0.05). A Kaplan-Meier curve stratified by initial fluid resuscitation dose was constructed for the probability of 28-day mortality. The medium-volume fluid group showed a significantly lower 28-day mortality rate than the high-volume group or the low-volume group (log-rank test, P = 0.0016). CONCLUSION: In septic shock patients, an initial fluid resuscitation rate of 20-30 mL/kg within the first hour may be associated with reduced 28-day mortality; however, this result needs to be confirmed by further high-quality randomized controlled clinical trials. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR-OOC-17013223. Registered 2 November 2017, http://www.chictr.org.cn/showproj.aspx?proj=22674.

Mesenchymal stem cells regulate the Th17/Treg cell balance partly through hepatocyte growth factor in vitro.

INTRODUCTION: Mesenchymal stem cells (MSCs) exert immunomodulatory functions by inducing the development and differentiation of naive T cells into T cells with an anti-inflammatory regulatory T cell (Treg) phenotype. Our previous study showed that hepatocyte growth factor (HGF) secreted by MSCs had immunomodulatory effects in the context of lipopolysaccharide (LPS) stimulation. We hypothesized that HGF is a key factor in the MSC-mediated regulation of the T helper 17 (Th17) cell/regulatory T (Treg) cell balance. METHODS: We investigated the effects of MSCs on the differentiation of CD4+ T cells and the functions of Th17/Treg cells in response to LPS stimulation by performing in vitro coculture experiments. MSCs were added to the upper chambers of cell culture inserts, and CD4+ T cells were plated in the lower chambers, followed by treatment with LPS or an anti-HGF antibody. Th17 (CD4+CD3+RORrt+) and Treg (CD4+CD25+Foxp3+) cell frequencies were analysed by flow cytometry, and the expression of Th17 cell- and Treg cell-related cytokines in the CD4+ T cells or culture medium was measured by quantitative PCR (qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Neutrophil functions were determined by flow cytometry after a coculture with Th17/Treg cells. RESULTS: The percentage of CD4+CD25+Foxp3+ cells was significantly increased in the CD4+ T cell population, while the percentage of CD4+CD3+RORrt+ cells was significantly decreased after MSC coculture. However, the MSC-induced effect was significantly inhibited by the anti-HGF antibody (p < 0.05). Furthermore, MSCs significantly inhibited the CD4+ T cell expression of IL-17 and IL-6 but increased the expression of IL-10 (p < 0.05 or p < 0.01); these effects were inhibited by the anti-HGF antibody (p < 0.05). In addition, CD4+ T cells cocultured with MSCs significantly inhibited neutrophil phagocytic and oxidative burst activities (p < 0.05 or p < 0.01); however, these MSC-induced effects were inhibited by the anti-HGF antibody (p < 0.05). CONCLUSION: These data suggested that MSCs induced the conversion of fully differentiated Th17 cells into functional Treg cells and thereby modulated the Th17/Treg cell balance in the CD4+ T cell population, which was partly attributed to HGF secreted by the MSCs.

Effect of Low-Dose Hydrocortisone Therapy in Adult Patients With Septic Shock: A Meta-Analysis With Trial Sequential Analysis of Randomized Controlled Trials.

BACKGROUND: The efficacy of low-dose hydrocortisone therapy in the management of septic shock remains controversial in critical care for many years. Hence, we performed this meta-analysis of randomized controlled trials (RCTs) with trial sequential analysis (TSA) to evaluate its effect on clinical outcome among adult patients with septic shock. METHODS: We identified relevant RCTs published from inception to March 7, 2018 comparing low-dose hydrocortisone with placebo or no intervention in adults admitted to the intensive care unit (ICU) for septic shock. Meta-analyses were performed for the primary and secondary outcomes. The risk of bias was assessed using the Cochrane Collaboration's instrument. Trial sequential analysis was used to pool the results from the included studies for the primary outcomes. RESULTS: Thirteen studies were retrieved by our literature search strategy. There were no significant differences in 28-day mortality (odds ratio [OR] = 0.90, 95% confidence interval [CI] = 0.81-1.00; P = .05) and hospital mortality (OR = 0.91, 95% CI = 0.82-1.02; P = .09) between the 2 groups, which were confirmed by TSA. However, there was a significant improvement in shock reversal in the hydrocortisone group (OR = 1.33, 95% CI = 1.02-1.72; P = .03). Furthermore, subgroup analyses revealed that hydrocortisone plus fludrocortisone statistically reduced the rate of 28-day mortality (OR = 0.79, 95% CI = 0.64-0.97; P = .03), ICU mortality (OR = 0.77, 95% CI = 0.63-0.95; P = .02), and hospital mortality (OR = 0.77, 95% CI = 0.63-0.95; P = .01) in comparison with the placebo, the results were also confirmed by TSA. CONCLUSION: Among adult patients with septic shock, the use of low-dose hydrocortisone compared with control did not confer overall survival benefits, albeit improving shock reversal rate. The benefit of reducing 28-day mortality, ICU mortality, and hospital mortality was observed in combination use of hydrocortisone and fludrocortisone.

Predictive accuracy of Sepsis-3 definitions for mortality among adult critically ill patients with suspected infection.

BACKGROUND: Sepsis-3 definitions have been published recently; however, their diagnostic value remains controversial. This study was to assess the accuracy of Sepsis-3 definitions compared to Sepsis-1 definitions by stratifying mortality among adult critically ill patients with suspected infection. METHODS: A multicenter, prospective cohort study was conducted from November 10, 2017 to October 10, 2018, in five Intensive Care Units (ICUs) at four teaching hospitals. Thirty-day mortality was compared across categories for both Sepsis-3 definitions and Sepsis-1 definitions, which were evaluated by logistic regression analysis followed by measurement of the area under the receiver operating characteristic curve (AUROC) for predicting 30-day mortality rates. RESULTS: Of the 749 enrolled patients, 644 (85.9%) were diagnosed with sepsis according to the Sepsis-1 definitions. Among those patients, 362 were diagnosed with septic shock (362/749, 48.3%). However, according to the Sepsis-3 definitions, there were 483 patients with a diagnosis of sepsis (483/749, 64.5%), among whom 299 patients were diagnosed with septic shock (299/749, 39.9%). According to the Sepsis-3 definitions, sepsis (sepsis and septic shock) patients had higher 30-day mortality (41.8%) than sepsis patients according to the Sepsis-1 definitions (31.8%, χ = 5.552, P = 0.020). The AUROC of systemic inflammatory response syndrome (SIRS) and quick sequential organ failure assessment (qSOFA) scores with regard to 30-day mortality rates were 0.609 (0.566-0.652) and 0.694 (0.654-0.733), respectively. However, the AUROC of SOFA scores (0.828 [0.795-0.862]) were significantly higher than that of SIRS or qSOFA scores (P < 0.001). CONCLUSION: In adult critically ill patients with suspected infection, the Sepsis-3 definitions were relatively accurate in stratifying mortality and were superior to the Sepsis-1 definitions. TRIAL REGISTRATION: www.chictr.org.cn (ChiCTR-OOC-17013223).

Effects of restrictive red blood cell transfusion on the prognoses of adult patients undergoing cardiac surgery: a meta-analysis of randomized controlled trials.

PURPOSE: Restrictive red blood cell transfusion strategies remain controversial in patients undergoing cardiac surgery. We performed a meta-analysis to assess the prognostic benefits of restrictive red blood cell transfusion strategies in patients undergoing cardiac surgery. METHODS: We identified randomized clinical trials through the 9th of December 2017 that investigated a restrictive red blood cell transfusion strategy versus a liberal transfusion strategy in patients undergoing cardiac surgery. Individual patient data from each study were collected. Meta-analyses were performed for the primary and secondary outcomes. The risk of bias was assessed using the Cochrane Risk of Bias Tool. A trial sequential analysis (TSA)-adjusted random-effects model was used to pool the results from the included studies for the primary outcomes. RESULTS: Seven trials involving a total of 8886 patients were included. The TSA evaluations suggested that this meta-analysis could draw firm negative results, and the data were sufficient. There was no evidence that the risk of 30-day mortality differed between the patients assigned to a restrictive blood cell transfusion strategy and a liberal transfusion strategy (odds ratio (OR) 0.98; 95% confidence interval (CI) 0.77 to 1.24; p = 0.87). Furthermore, the study suggested that the restrictive transfusion strategy was not associated with significant increases in pulmonary morbidity (OR 1.09; 95% CI 0.88 to 1.34; p = 0.44), postoperative infection (OR 1.11; 95% CI 0.95 to 1.3; p = 0.58), acute kidney injury (OR 1.03; 95% CI 0.92 to 1.14; p = 0.71), acute myocardial infarction (OR 1.01; 95% CI 0.80 to 1.27; p = 0.78), or cerebrovascular accidents (OR 0.97; 95% CI 0.72 to 1.30; p = 0.66). CONCLUSIONS: Our meta-analysis demonstrates that the restrictive red blood cell transfusion strategy was not inferior to the liberal strategy with respect to 30-day mortality, pulmonary morbidity, postoperative infection, cerebrovascular accidents, acute kidney injury, or acute myocardial infarction, and fewer red blood cells were transfused.

Effect of levosimendan on prognosis in adult patients undergoing cardiac surgery: a meta-analysis of randomized controlled trials.

BACKGROUND: Small trials suggest that levosimendan is associated with a favorable outcome in patients undergoing cardiac surgery. However, recently published larger-scale trials did not provide evidence for a similar benefit from levosimendan. We performed a meta-analysis to assess the survival benefits of levosimendan in patients undergoing cardiac surgery and to investigate its effects in subgroups of patients with preoperative low-ejection fraction (EF). METHODS: We identified randomized clinical trials through 20 April 2017 that investigated levosimendan therapy versus control in patients undergoing cardiac surgery. Individual patient data from each study were compiled. Meta-analyses were performed for primary outcomes, secondary outcomes and serious adverse events, and subgroup analyses according to the preoperative EF of enrolled patients were also conducted. The risk of bias was assessed using the Cochrane risk-of-bias tool. RESULTS: Seventeen studies involving a total of 2756 patients were included. Levosimendan therapy was associated with a significant reduction in 30-day mortality (RR 0.67; 95% CI, 0.49 to 0.93; p = 0.02) and reduced the risk of death in single-center trials (RR 0.49; 95% CI, 0.30 to 0.79; p = 0.004) and in subgroup trials of inferior quality (RR 0.39; 95% CI, 0.17 to 0.92; p = 0.02); however, in multicenter and in high-quality subgroup-analysis trials, no significant difference in mortality was observed between patients who received levosimendan therapy and controls (p > 0.05). However, in high-quality subgroup trials, levosimendan therapy was associated with reduced mortality in patients in a preoperative low-EF subgroup (RR 0.58; 95% CI, 0.38 to 0.88; p = 0.01). Similarly, only patients in the preoperative low-EF subgroup benefited in terms of reduced risk of renal replacement therapy (RR 0.54; 95% CI, 0.34 to 0.85; p = 0.007). Furthermore, levosimendan therapy was associated with a significant reduction in intensive care unit (ICU) length of stay (MDR -17.19; 95% CI, -34.43 to -2.94; p = 0.02). CONCLUSIONS: In patients undergoing cardiac surgery, the benefit of levosimendan in terms of survival was not shown in multicenter or in high-quality trials; however, levosimendan therapy was associated with reduced mortality in patients with preoperative ventricular systolic dysfunction.

Early initiation of low-dose hydrocortisone treatment for septic shock in adults: A randomized clinical trial.

BACKGROUND: Physiologic dose hydrocortisone is part of the suggested adjuvant therapies for patients with septic shock. However, the association between the corticosteroid therapy and mortality in patients with septic shock is still not clear. Some authors considered that the mortality is related to the time frame between development of septic shock and start of low dose hydrocortisone. Thus we designed a placebo-controlled, randomized clinical trial to assess the importance of early initiation of low dose hydrocortisone for the final outcome. METHODS: A total of 118 patients with septic shock were recruited in the study. All eligible patients were randomized to receive hydrocortisone (n=58) or normal saline (n=60). The study medication (hydrocortisone and normal saline) was initiated simultaneously with vasopressors. The primary end-point was 28-day mortality. The secondary end-points were the reversal of shock, in-hospital mortality and the duration of ICU and hospital stay. RESULTS: The proportion of patients with reversal of shock was similar in the two groups (P=0.602); There were no significant differences in 28-day or hospital all-cause mortality; length of stay in the ICU or hospital between patients treated with hydrocortisone or normal saline. CONCLUSION: The early initiation of low-dose of hydrocortisone did not decrease the risk of mortality, and the length of stay in the ICU or hospital in adults with septic shock. TRIAL REGISTRATION: www.clinicaltrials.govNCT02580240.

The Effect of Early Goal-Directed Therapy on Outcome in Adult Severe Sepsis and Septic Shock Patients: A Meta-Analysis of Randomized Clinical Trials.

BACKGROUND: Whether early goal-directed therapy (EGDT) improves outcome in severe sepsis and septic shock remains unclear. We performed a meta-analysis of existing clinical trials to examine whether EGDT improved outcome in the resuscitation of adult sepsis patients compared with control care. METHODS: We searched for eligible studies using MEDLINE, Elsevier, Cochrane Central Register of Controlled Trials, and Web of Science databases. Studies were eligible if they compared the effects of EGDT versus control care on mortality in adult patients with severe sepsis and septic shock. Two reviewers extracted data independently. Data including mortality, sample size of the patients with severe sepsis and septic shock, and resuscitation end points were extracted. Data were analyzed using methods recommended by the Cochrane Collaboration Review Manager 4.2 software. Random errors were evaluated by trial sequential analysis (TSA). RESULTS: Nine studies compared EGDT with control care, and 5202 severe sepsis and septic shock patients were included. A nonsignificant trend toward reduction in the longest all-cause mortality was observed in the EGDT group compared with control care (relative risk, 0.89; 99% confidence interval, 0.74-1.07; P = 0.10). However, EGDT significantly reduced intensive care unit mortality in severe sepsis and septic shock patients (relative risk, 0.72; 99% confidence interval, 0.57-0.90; P = 0.0002). TSA indicated lack of firm evidence for a beneficial effect. CONCLUSIONS: In this meta-analysis, a nonsignificant trend toward reduction in the longest all-cause mortality in patients resuscitated with EGDT was noted. However, EGDT significantly reduced intensive care unit mortality in severe sepsis and septic shock patients. TSA indicated a lack of firm evidence for the results. More powered, randomized controlled trials are needed to determine the effects.

The Orphan Receptor Tyrosine Kinase ROR2 Facilitates MSCs to Repair Lung Injury in ARDS Animal Model.

There are some limitations to the therapeutic effects of mesenchymal stem cells (MSCs) on acute respiratory distress syndrome (ARDS) due to their low engraftment and differentiation rates in lungs. We found previously that noncanonical Wnt5a signaling promoted the differentiation of mouse MSCs (mMSCs) into type II alveolar epithelial cells (AT II cells), conferred resistance to oxidative stress, and promoted migration of MSCs in vitro. As receptor tyrosine kinase-like orphan receptor 2 (ROR2) is an essential receptor for Wnt5a, it was reasonable to deduce that ROR2 might be one of the key molecules for the therapeutic effect of MSCs in ARDS. The mMSCs that stably overexpressed ROR2 or the green fluorescent protein (GFP) control were transplanted intratracheally into the ARDS mice [induced by intratracheal injection of lipopolysaccharide (LPS)]. The results showed that ROR2-overexpressing mMSCs led to more significant effects than the GFP controls, including the retention of the mMSCs in the lung, differentiation into AT II cells, improvement of alveolar epithelial permeability, improvement of acute LPS-induced pulmonary inflammation, and, finally, reduction of the pathological impairment of the lung tissue. In conclusion, MSCs that overexpress ROR2 could further improve MSC-mediated protection against epithelial impairment in ARDS.

Synergism of MSC-secreted HGF and VEGF in stabilising endothelial barrier function upon lipopolysaccharide stimulation via the Rac1 pathway.

BACKGROUND: Mesenchymal stem cells (MSCs) stabilise endothelial barrier function in acute lung injury via paracrine hepatocyte growth factor (HGF). Vascular endothelial growth factor (VEGF), which is secreted by MSCs, is another key regulator of endothelial permeability; however, its role in adjusting permeability remains controversial. In addition, whether an interaction occurs between HGF and VEGF, which are secreted by MSCs, is not completely understood. METHODS: We introduced a co-cultured model of human pulmonary microvascular endothelial cells (HPMECs) and MSC conditioned medium (CM) collected from MSCs after 24 h of hypoxic culture. The presence of VEGF and HGF in the MSC-CM was neutralised by anti-VEGF and anti-HGF antibodies, respectively. To determine the roles and mechanisms of MSC-secreted HGF and VEGF, we employed recombinant humanised HGF and recombinant humanised VEGF to co-culture with HPMECs. Additionally, we employed the RhoA inhibitor C3 transferase and the Rac1 inhibitor NSC23766 to inhibit the activities of RhoA and Rac1 in HPMECs treated with MSC-CM or VEGF/HGF with the same dosage as in the MSC-CM. Then, endothelial paracellular and transcellular permeability was detected. VE-cadherin, occludin and caveolin-1 protein expression in HPMECs was measured by western blot. Adherens junction proteins, including F-actin and VE-cadherin, were detected by immunofluorescence. RESULTS: MSC-CM treatment significantly decreased lipopolysaccharide-induced endothelial paracellular and transcellular permeability, which was significantly inhibited by pretreatment with HGF antibody or with both VEGF and HGF antibodies. Furthermore, MSC-CM treatment increased the expression of the endothelial intercellular adherence junction proteins VE-cadherin and occludin and decreased the expression of caveolin-1 protein. MSC-CM treatment also decreased endothelial apoptosis and induced endothelial cell proliferation; however, the effects of MSC-CM treatment were inhibited by pretreatment with HGF antibody or with both HGF and VEGF antibodies. Additionally, the effects of MSC-CM and VEGF/HGF on reducing endothelial paracellular and transcellular permeability were weakened when HPMECs were pretreated with the Rac1 inhibitor NSC23766. CONCLUSION: HGF secreted by MSCs protects the endothelial barrier function; however, VEGF secreted by MSCs may synergize with HGF to stabilise endothelial cell barrier function. Rac1 is the pathway by which MSC-secreted VEGF and HGF regulate endothelial permeability.

Interaction between mesenchymal stem cells and endothelial cells restores endothelial permeability via paracrine hepatocyte growth factor in vitro.

INTRODUCTION: Mesenchymal stem cells (MSCs) have potent stabilising effects on vascular endothelium injury, inhibiting endothelial permeability in lung injury via paracrine hepatocyte growth factor (HGF). Recently, it has been indicated that MSCs secrete more factors by MSC-endothelial cell (MSC-EC) interactions. We hypothesised that MSC-EC interactions restore endothelial permeability induced by lipopolysaccharide (LPS) via paracrine HGF. METHODS: We investigated the endothelial permeability induced by LPS under two co-culture conditions. Human pulmonary microvascular endothelial cells (HPMECs) were added into the upper chambers of cell-culture inserts, while two different co-culture conditions were used in the lower side of the transwells, as follows: (1) MSC-EC interaction group: MSCs and HPMECs contact co-culture; (2) MSC group: MSCs only. The endothelial paracellular and transcellular permeabilities in the upper side of transwells were detected. Then the concentration of HGF was measured in the culture medium by using an enzyme-linked immunosorbent assay kit, followed by neutralisation of HGF with anti-HGF antibody in the co-culture medium. In addition, adherens junction and cytoskeleton protein expressions were measured by Western blot and immunofluorescence. HPMEC proliferation was analysed by bromodeoxyuridine incorporation assay. RESULTS: The paracellular permeability significantly increased after LPS stimulation in a dose-dependent and time-dependent manner. Meanwhile, MSC-EC interaction more significantly decreased endothelial paracellular and transcellular permeability induced by LPS. Moreover, HGF levels in the MSC-EC interaction group were much higher than those of the MSC group. However, neutralising HGF with anti-HGF antibody inhibited the role of MSC-EC interaction in improving endothelial permeability. Compared with the MSC group, MSC-EC interaction increased vascular endothelial (VE)-cadherin and occludin protein expression, reduced caveolin-1 protein expression in HPMECs, and restored remodelling of F-actin and junctional localisation of VE-cadherin. Furthermore, the proliferation ratio in the MSC-EC interaction group was higher than that of the MSC group. However, the effects of MSCs were significantly blocked by anti-HGF antibody. CONCLUSIONS: These data suggested that MSC-EC interaction decreased endothelial permeability induced by LPS, which was attributed mainly to HGF secreted by MSCs. The main mechanisms by which HGF restored the integrity of endothelial monolayers were remodelling of endothelial intercellular junctions, decreasing caveolin-1 protein expression, and inducing proliferation in HPMECs.

Activation of Wnt/ß-catenin signalling promotes mesenchymal stem cells to repair injured alveolar epithelium induced by lipopolysaccharide in mice.

INTRODUCTION: Mesenchymal stem cells (MSCs) have potential for re-epithelization and recovery in acute respiratory distress syndrome (ARDS). In a previous in vitro study, the results showed that the canonical Wnt/ß-catenin pathway promoted the differentiation of MSCs into type II alveolar epithelial cells, conferred resistance to oxidative stress, and promoted their migration, suggesting that the Wnt/ß-catenin pathway might be one of the key mechanisms underling the therapeutic effect of mouse MSCs in ARDS. METHODS: Mouse MSCs stable transfected with ß-catenin or green fluorescent protein control were transplanted intratracheally into the ARDS mice induced by lipopolysaccharide. Lung tissue injury and repair assessment were examined using haematoxylin and eosin staining, lung injury scoring, Masson's trichrome staining and fibrosis scoring. Homing and differentiation of mouse MSCs were assayed by labelling and tracing MSCs using NIR815 dye, immunofluorescent staining, and Western immunoblot analysis. The inflammation and permeability were evaluated by detecting the cytokine and protein measurements in bronchoalveolar lavage fluid using enzyme-linked immunosorbent assay. RESULTS: In this study, ß-catenin-overexpressing MSC engraftment led to more significant effects than the GFP controls, including the retention of the MSCs in the lung, differentiation into type II alveolar epithelial cells, improvement in alveolar epithelial permeability, and the pathologic impairment of the lung tissue. CONCLUSION: These results suggest that the activation of canonical Wnt/ß-catenin pathway by mouse MSCs by overexpressing ß-catenin could further improve the protection of mouse MSCs against epithelial impair and the therapeutic effects of mouse MSCs in ARDS mice.

MSCs modified with ACE2 restore endothelial function following LPS challenge by inhibiting the activation of RAS.

Angiotensin (Ang) II plays an important role in the process of endothelial dysfunction in acute lung injury (ALI) and is degraded by angiotensin-converting enzyme2 (ACE2). However, treatments that target ACE2 to injured endothelium and promote endothelial repair of ALI are lacking. Mesenchymal stem cells (MSCs) are capable of homing to the injured site and delivering a protective gene. Our study aimed to evaluate the effects of genetically modified MSCs, which overexpress the ACE2 protein in a sustained manner via a lentiviral vector, on Ang II production in endothelium and in vitro repair of lipopolysaccharide (LPS)-induced endothelial injury. We found that the efficiency of lentiviral vector transduction of MSCs was as high as 97.8% and was well maintained over 30 passages. MSCs modified with ACE2 showed a sustained high expression of ACE2 mRNA and protein. The modified MSCs secreted soluble ACE2 protein into the culture medium, which reduced the concentration of Ang II and increased the production of Ang 1-7. MSCs modified with ACE2 were more effective at restoring endothelial function than were unmodified MSCs, as shown by the enhanced survival of endothelial cells; the downregulated production of inflammatory mediators, including ICAM-1, VCAM-1, TNF-α, and IL-6; reduced paracellular permeability; and increased expression of VE-cadherin. These data demonstrate that MSCs modified to overexpress the ACE2 gene can produce biologically active ACE2 protein over a sustained period of time and have an enhanced ability to promote endothelial repair after LPS challenge. These results encourage further testing of the beneficial effects of ACE2-modified MSCs in an ALI animal model.

Comparison of the effects of albumin and crystalloid on mortality in adult patients with severe sepsis and septic shock: a meta-analysis of randomized clinical trials.

INTRODUCTION: The aim of this study was to examine whether albumin reduced mortality when employed for the resuscitation of adult patients with severe sepsis and septic shock compared with crystalloid by meta-analysis. METHODS: We searched for and gathered data from MEDLINE, Elsevier, Cochrane Central Register of Controlled Trials and Web of Science databases. Studies were eligible if they compared the effects of albumin versus crystalloid therapy on mortality in adult patients with severe sepsis and septic shock. Two reviewers extracted data independently. Disagreements were resolved by discussion with other two reviewers until a consensus was achieved. Data including mortality, sample size of the patients with severe sepsis, sample size of the patients with septic shock and resuscitation endpoints were extracted. Data were analyzed by the methods recommended by the Cochrane Collaboration Review Manager 4.2 software. RESULTS: A total of 5,534 records were identified through the initial search. Five studies compared albumin with crystalloid. In total, 3,658 severe sepsis and 2,180 septic shock patients were included in the meta-analysis. The heterogeneity was determined to be non-significant (P = 0.86, I(2) = 0%). Compared with crystalloid, a trend toward reduced 90-day mortality was observed in severe sepsis patients resuscitated with albumin (odds ratio (OR) 0.88; 95% CI, 0.76 to 1.01; P = 0.08). However, the use of albumin for resuscitation significantly decreased 90-day mortality in septic shock patients (OR 0.81; 95% CI, 0.67 to 0.97; P = 0.03). Compared with saline, the use of albumin for resuscitation slightly improved outcome in severe sepsis patients (OR 0.81; 95% CI, 0.64 to 1.08; P = 0.09). CONCLUSIONS: In this meta-analysis, a trend toward reduced 90-day mortality was observed in severe sepsis patients resuscitated with albumin compared with crystalloid and saline. Moreover, the 90-day mortality of patients with septic shock decreased significantly.

Stable genetic alterations of ß-catenin and ROR2 regulate the Wnt pathway, affect the fate of MSCs.

The Wnt pathways have been shown to be critical for the fate of mesenchymal stem cells (MSCs) in vitro, but their roles in MSCs in vivo remain poorly characterized due to the lack of stable alterations in their signaling. In the present study, we constructed long-term and stable mMSCs lines with activated and inactivated ß-catenin (the key molecule of the canonical Wnt signaling pathway) or ROR2 (the key molecule of the noncanonical Wnt5a/ROR2 signaling pathway) modifications with lentiviral vectors. We found that the transduction efficiencies mediated by the lentiviral vectors were 92.61-97.04% and were maintained over 20 passages of mMSCs. Transfection by lentiviral vectors not only regulated the mRNA and protein expression of ß-catenin or ROR2 but also regulated nuclear ß-catenin accumulation or the Wnt5a/JNK and Wnt5a/PKC pathways belonging to the canonical Wnt and noncanonical Wnt5a/ROR2 pathways, respectively. ß-Catenin or ROR2 gene overexpression promoted mMSC proliferation, migration and differentiation into osteoblasts, while inhibiting the adipogenic differentiation of mMSCs. In contrast, inactivation of the ß-catenin or ROR2 genes resulted in the opposite effects. Therefore, these results confirm that lentiviral vector transduction can facilitate sustained and efficient gene modification of the Wnt pathway in mMSCs. This study provides a method to investigate the effects of the Wnt pathway on the fate of mMSCs in vivo and for the further improvement of MSC-based therapies.

The effect of glutamine therapy on outcomes in critically ill patients: a meta-analysis of randomized controlled trials.

INTRODUCTION: Glutamine supplementation is supposed to reduce mortality and nosocomial infections in critically ill patients. However, the recently published reducing deaths due to oxidative stress (REDOX) trials did not provide evidence supporting this. This study investigated the impact of glutamine-supplemented nutrition on the outcomes of critically ill patients using a meta-analysis. METHODS: We searched for and gathered data from the Cochrane Central Register of Controlled Trials, MEDLINE, Elsevier, Web of Science and ClinicalTrials.gov databases reporting the effects of glutamine supplementation on outcomes in critically ill patients. We produced subgroup analyses of the trials according to specific patient populations, modes of nutrition and glutamine dosages. RESULTS: Among 823 related articles, eighteen Randomized Controlled Trials (RCTs) met all inclusion criteria. Mortality events among 3,383 patients were reported in 17 RCTs. Mortality showed no significant difference between glutamine group and control group. In the high dosage subgroup (above 0.5 g/kg/d), the mortality rate in the glutamine group was significantly higher than that of the control group (relative risk (RR) 1.18; 95% confidence interval (CI), 1.02 to 1.38; P = 0.03). In 15 trials, which included a total of 2,862 patients, glutamine supplementation reportedly affected the incidence of nosocomial infections in the critically ill patients observed. The incidence of nosocomial infections in the glutamine group was significantly lower than that of the control group (RR 0.85; 95% CI, 0.74 to 0.97; P = 0.02). In the surgical ICU subgroup, glutamine supplementation statistically reduced the rate of nosocomial infections (RR 0.70; 95% CI, 0.52 to 0.94; P = 0.04). In the parental nutrition subgroup, glutamine supplementation statistically reduced the rate of nosocomial infections (RR 0.83; 95% CI, 0.70 to 0.98; P = 0.03). The length of hospital stay was reported in 14 trials, in which a total of 2,777 patients were enrolled; however, the patient length of stay was not affected by glutamine supplementation. CONCLUSIONS: Glutamine supplementation conferred no overall mortality and length of hospital stay benefit in critically ill patients. However, this therapy reduced nosocomial infections among critically ill patients, which differed according to patient populations, modes of nutrition and glutamine dosages.