Jiali Zhu

Upregulation of programmed death-1 on T cells and programmed death ligand-1 on monocytes in septic shock patients

IntroductionStudies on the role of programmed death-1(PD-1) and its main ligand (PD-L1) during experimental models of sepsis have shown that the PD-1/PD-L1 pathway plays a pathologic role in altering microbial clearance, the innate inflammatory response and accelerated apoptosis in sepsis. However, the expression of PD-1 and PD-L1 and their role during the development of immune suppression in septic patients have not been elucidated. The present study was designed to determine whether the expression of PD-1 and PD-L1 is upregulated in septic shock patients and to explore the role of this pathway in sepsis-induced immunosuppression.MethodsNineteen septic shock patients and 22 sex-matched and age-matched healthy controls were prospectively enrolled. Apoptosis in lymphocyte subpopulations and PD-1/PD-L1 expression on peripheral T cells, B cells and monocytes were measured using flow cytometry. Apoptosis of T cells induced by TNFα or T-cell receptor ligation in vitro and effects of anti-PD-L1 antibody administration were measured by flow cytometry. CD14+ monocytes of septic shock patients were purified and incubated with either lipopolysaccharide, anti-PD-L1 antibody, isotype antibody, or a combination of lipopolysaccharide and anti-PD-L1 antibody or isotype antibody. Supernatants were harvested to examine production of cytokines by ELISA.ResultsCompared with healthy controls, septic shock induced a marked increase in apoptosis as detected by the annexin-V binding and active caspase-3 on CD4+ T cells, CD8+ T cells and CD19+ B cells. Expression of PD-1 on T cells and of PD-L1 on monocytes was dramatically upregulated in septic shock patients. PD-1/PD-L1 pathway blockade in vitro with anti-PD-L1 antibody decreased apoptosis of T cells induced by TNFα or T-cell receptor ligation. Meanwhile, this blockade potentiated the lipopolysaccharide-induced TNFα and IL-6 production and decreased IL-10 production by monocytes in vitro.ConclusionsThe expression of PD-1 on T cells and PD-L1 on monocytes was upregulated in septic shock patients. The PD-1/PD-L1 pathway might play an essential role in sepsis-induced immunosuppression.

Granulocyte-colony stimulating factor (G-CSF) and granulocyte-macrophage colony stimulating factor (GM-CSF) for sepsis: a meta-analysis

IntroductionTo investigate the effects of G-CSF or GM-CSF therapy in non-neutropenic patients with sepsis.MethodsA systematic literature search of Medline, Embase and Cochrane Central Register of Controlled Trials was conducted using specific search terms. A manual review of references was also performed. Eligible studies were randomized control trials (RCTs) that compared granulocyte-colony stimulating factor (G-CSF) or granulocyte-macrophage colony stimulating factor (GM-CSF) therapy with placebo for the treatment of sepsis in adults. Main outcome measures were all-cause mortality at 14 days and 28 days after initiation of G-CSF or GM-CSF therapy, in-hospital mortality, reversal rate from infection, and adverse events.ResultsTwelve RCTs with 2,380 patients were identified. In regard to 14-day mortality, a total of 9 death events occurred among 71 patients (12.7%) in the treatment group compared with 13 events among 67 patients (19.4%) in the placebo groups. Meta-analysis showed there was no significant difference in 28-day mortality when G-CSF or GM-CSF were compared with placebo (relative risks (RR) = 0.93, 95% confidence interval (CI): 0.79 to 1.11, P = 0.44; P for heterogeneity = 0.31, I2 = 15%). Compared with placebo, G-CSF or GM-CSF therapy did not significantly reduce in-hospital mortality (RR = 0.97, 95% CI: 0.69 to 1.36, P = 0.86; P for heterogeneity = 0.80, I2 = 0%). However, G-CSF or GM-CSF therapy significantly increased the reversal rate from infection (RR = 1.34, 95% CI: 1.11 to 1.62, P = 0.002; P for heterogeneity = 0.47, I2 = 0%). No significant difference was observed in adverse events between groups (RR = 0.93, 95% CI: 0.70 to 1.23, P = 0.62; P for heterogeneity = 0.03, I2 = 58%). Sensitivity analysis by excluding one trial did not significantly change the results of adverse events (RR = 1.05, 95% CI: 0.84 to 1.32, P = 0.44; P for heterogeneity = 0.17, I2 = 36%).ConclusionsThere is no current evidence supporting the routine use of G-CSF or GM-CSF in patients with sepsis. Large prospective multicenter clinical trials investigating monocytic HLA-DR (mHLA-DR)-guided G-CSF or GM-CSF therapy in patients with sepsis-associated immunosuppression are warranted.

The Timing of Tracheotomy in Critically Ill Patients Undergoing Mechanical Ventilation: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND The objective of this study was to systematically review and quantitatively synthesize all randomized controlled trials (RCTs), comparing important outcomes in ventilated critically ill patients who received an early or late tracheotomy. METHODS A systematic literature search of PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, the Cochrane Central Register of Controlled Trials, the National Research Register, the National Health Service Trusts Clinical Trials Register, and the Medical Research Council UK database was conducted using specific search terms. Eligible studies were RCTs that compared early tracheotomy (ET) with either late tracheotomy or prolonged endotracheal intubation in critically ill adult patients. RESULTS Seven trials with 1,044 patients were analyzed. ET did not significantly reduce short-term mortality (relative risk [RR], 0.86; 95% CI, 0.65-1.13), long-term mortality (RR, 0.84; 95% CI, 0.68-1.04), or incidence of ventilator-associated pneumonia (RR, 0.94; 95% CI, 0.77-1.15) in critically ill patients. The timing of the tracheotomy was not associated with a markedly reduced duration of mechanical ventilation (MV) (weighted mean difference [WMD], -3.90 days; 95% CI, -9.71-1.91) or sedation (WMD, -7.09 days; 95% CI, -14.64-0.45), shorter stay in ICU (WMD, -6.93 days; 95% CI, -16.50-2.63) or hospital (WMD, 1.45 days; 95% CI, -5.31-8.22), or more complications (RR, 0.94; 95% CI, 0.66-1.34). CONCLUSIONS The present meta-analysis suggested that the timing of the tracheotomy did not significantly alter important clinical outcomes in critically ill patients. The duration of MV and sedation, as well as the long-term outcomes of ET in mechanically ventilated patients, should be evaluated in rigorously designed and adequately powered RCTs in the future.

Baicalin Improves Survival in a Murine Model of Polymicrobial Sepsis via Suppressing Inflammatory Response and Lymphocyte Apoptosis

Background An imbalance between overwhelming inflammation and lymphocyte apoptosis is the main cause of high mortality in patients with sepsis. Baicalin, the main active ingredient of the Scutellaria root, exerts anti-inflammatory, anti-apoptotic, and even antibacterial properties in inflammatory and infectious diseases. However, the therapeutic effect of baicalin on polymicrobial sepsis remains unknown. Methodology/Principal Findings Polymicrobial sepsis was induced by cecal ligation and puncture (CLP) in C57BL/6 mice. Mice were infused with baicalin intraperitoneally at 1 h, 6 h and 12 h after CLP. Survival rates were assessed over the subsequent 8 days. Bacterial burdens in blood and peritoneal cavity were calculated to assess the bacterial clearance. Neutrophil count in peritoneal lavage fluid was also calculated. Injuries to the lung and liver were detected by hematoxylin and eosin staining. Levels of cytokines, including tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-10 and IL-17, in blood and peritoneum were measured by enzyme-linked immunosorbent assay. Adaptive immune function was assessed by apoptosis of lymphocytes in the thymus and counts of different cell types in the spleen. Baicalin significantly enhanced bacterial clearance and improved survival of septic mice. The number of neutrophils in peritoneal lavage fluid was reduced by baicalin. Less neutrophil infiltration of the lung and liver in baicalin-treated mice was associated with attenuated injuries to these organs. Baicalin significantly reduced the levels of proinflammatory cytokines but increased the level of anti-inflammatory cytokine in blood and peritoneum. Apoptosis of CD3+ T cell was inhibited in the thymus. The numbers of CD4+, CD8+ T lymphocytes and dendritic cells (DCs) were higher, while the number of CD4+CD25+ regulatory T cells was lower in the baicalin group compared with the CLP group. Conclusions/Significance Baicalin improves survival of mice with polymicrobial sepsis, and this may be attributed to its antibacterial property as well as its anti-inflammatory and anti-apoptotic effects.

Neutralisation of Peritoneal IL-17A Markedly Improves the Prognosis of Severe Septic Mice by Decreasing Neutrophil Infiltration and Proinflammatory Cytokines

Purpose The current study aimed to elucidate the role of peritoneal fluid IL-17A in septic mice, and the effects of intraperitoneal or intravenous blockade of the IL-17A pathway by anti-IL17A antibody on survival, plasma, and peritoneal cavity cytokine profile in a murine caecal ligation and puncture (CLP) sepsis model. The main source of peritoneal fluid IL-17A in septic mice was identified. Methods Male C57BL/6 mice that underwent severe CLP or sham surgery were intraperitoneally or intravenously administered anti-IL17A antibodies or isotype antibodies. The survival rates were observed. IL-17A, TNF-α, and IL-6 cytokine levels were measured by ELISA. Surface and intracellular IL-17A immunofluorescence stains were detected by flow cytometry to identify the IL-17A–producing cells. Results The IL-17A level was elevated much higher and earlier in peritoneal fluid than in the blood of the CLP mice. The intraperitoneal IL-17A blockade more significantly protects against CLP-induced mortality than intravenous blockade because of decreased TNF-α and IL-6 levels both in peritoneal fluid and blood, neutrophil infiltration in the peritoneal cavity, and lung injury. γδ T lymphocytes were identified to be the main source of IL-17A in the peritoneal fluid of septic mice. Conclusions The earlier and higher elevated IL-17A derived from γδ T cells in peritoneal fluid plays a critical role during polymicrobial severe sepsis and effect of intraperitoneal IL-17A antibody administration superior to intravenous administration on survival of severe CLP-induced septic mice. The intraperitoneal blockade of IL-17A decreases proinflammatory cytokine production, neutrophil infiltration, and lung injury, thereby improving septic mice survival, which provides a new potential therapy target for sepsis.

Ginsenoside Rg1 improves lipopolysaccharide-induced acute lung injury by inhibiting inflammatory responses and modulating infiltration of M2 macrophages.

Ginsenoside Rg1 (Rg1), the major effective component of ginseng, has been reported to have potent anti-inflammatory properties. However, the effect of ginsenoside Rg1 on lipopolysaccharide (LPS) -induced acute lung injury (ALI) in mice was unknown. The present study was designed to investigate the protective role of Rg1 on LPS-induced ALI and explore the potential mechanisms. The mice were divided randomly into four groups: the sham group, the LPS group and the LPS+Rg1 (40 mg/kg or 200mg/kg) pretreatment groups. All mice received Rg1 or an equivalent volume of phosphate buffer saline (PBS) intraperitoneally 1h before LPS administration. Edema quantification, histology, and apoptosis were detected 6h after LPS administration. The number of inflammatory cells, the percentage of alternative activated (M2) macrophages and the exudate quantification in bronchoalveolar lavage fluid (BALF) were evaluated. The caspase 3 expression, and the levels of phosphorylated IκB-α and p65 were tested. The results showed that the Rg1 pretreatment group markedly improved lung damage, modulated the infiltration of neutrophils and M2 macrophages, prevented the production of protein and proinflammatory cytokines in BALF, and inhibited apoptosis in lung. We also found that Rg1 suppressed NF-κB and caspase 3 activation. These data suggest that Rg1 plays a protective role against LPS-induced ALI by ameliorating inflammatory responses, regulating the infiltration of M2 macrophages, and inhibiting pulmonary cell apoptosis.

PD-L1 Blockade Attenuated Sepsis-Induced Liver Injury in a Mouse Cecal Ligation and Puncture Model

Liver plays a major role in hypermetabolism and produces acute phase proteins during systemic inflammatory response syndrome and it is of vital importance in host defense and bacteria clearance. Our previous studies indicated that programmed death-1 (PD-1) and its ligand programmed death ligand-1 (PD-L1) are crucial modulators of host immune responses during sepsis. Our current study was designed to investigate the role of PD-L1 in sepsis-induced liver injury by a mouse cecal ligation and puncture (CLP) model. Our results indicated that there was a significant increase of PD-L1 expression in liver after CLP challenge compared to sham-operated controls, in terms of levels of mRNA transcription and immunohistochemistry. Anti-PD-L1 antibody significantly alleviated the morphology of liver injury in CLP mice. Anti-PD-L1 antibody administration decreased ALT and AST release in CLP mice, decreased the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 mRNA in liver after sepsis challenge. Thus, anti-PD-L1 antibody might have a therapeutic potential in attenuating liver injury in sepsis.

Salidroside attenuates concanavalin A-induced hepatitis via modulating cytokines secretion and lymphocyte migration in mice.

Salidroside, isolated from the medicinal plant Rhodiola, was reported to serve as an “adaptogen.” This study was designed to explore the protective effect of salidroside on concanavalin A- (Con A-) induced hepatitis in mice and investigate potential mechanisms. C57BL/6 mice were randomly divided into control group, Con A group, and salidroside group. Salidroside (50 mg/kg) was injected intravenously followed by Con A administration. The levels of ALT, AST, inflammatory cytokines and CXCL-10 were examined. The pathological damage of livers was assessed, the amounts of phosphorylated IκBα and p65 were measured, and the numbers of CD4+ and CD8+ T lymphocytes in the blood, spleen and infiltrated in the liver were calculated. Our results showed that salidroside pretreatment reduced the levels of ALT, AST dramatically and suppressed the secretion of proinflammatory cytokines through downregulating the activity of NF-κB partly. Salidroside altered the distribution of CD4+ and CD8+ T lymphocyte in the liver and spleen through regulating CXCL-10 and decreased the severity of liver injuries. In conclusion, these results confirm the efficacy of salidroside in the prevention of immune mediated hepatitis in mice.

Soluble Tumor Necrosis Factor Related Apoptosis Inducing Ligand Level as a Predictor of Severity of Sepsis and the Risk of Mortality in Septic Patients

Background Tumor necrosis factor related apoptosis inducing ligand (TRAIL) as a member of the TNF gene superfamily induces apoptosis primarily in tumor cells. TRAIL also plays an important role in the modulation of inflammatory responses, especially in the process of immune paralysis. The aim of the present study was to examine soluble TRAIL (sTRAIL) levels in septic patients in an attempt to explore the association between sTRAIL level and the risk of mortality. Methods Plasma sTRAIL levels were detected by ELISA in 50 septic patients and 20 healthy volunteers. HLA-DR expression in monocytes was detected by flow cytometry. Selective biochemical parameters were recorded, and patients were monitored in a 28-day period for mortality. Results The mean plasma sTRAIL level in septic patients was significantly lower than that in healthy controls (16.9±8.3 vs. 68.3±8.6 pg/ml, P<0.01), and was significantly higher in 28-day survivors than those in non-survivors (19.4±9.8 vs. 13.9±4.7 pg/ml, P<0.05). Univariate analysis indicated that plasma sTRAIL level was positively correlated with monocyte and lymphocyte counts and HLA-DR expression level (r = 0.5, P<0.01; r = 0.3, P<0.05; r = 0.43, P<0.01, respectively). STRAIL level was negatively correlated with APACHE II score, BUN and age (r = −0.48, P<0.01; r = −0.29, P<0.05; r = −0.45, P<0.01, respectively). Multiple linear regression analysis indicated that the predictor of plasma soluble TRAIL level was HLA-DR expression (P<0.01). Conclusion Low plasma sTRAIL levels were associated with immune paralysis and a high risk of mortality in patients with septic shock. sTRAIL may prove to be a potential biomarker of immune function and predict the survival of septic patients.