Serum lipid profile, cytokine production, and clinical outcome in patients with severe sepsis

Effect of low high-density lipoprotein levels on mortality of septic patients: A systematic review and meta-analysis of cohort studies

BACKGROUND

An increase in high-density lipoprotein (HDL) is well associated with a decreased cardiovascular risk, especially atherosclerosis. Recent studies suggest that lower levels of HDL may also be associated with an increased risk of sepsis and an increased rate of mortality in septic patients. However, this conclusion remains controversial.

METHODS

MEDLINE, EMBASE, and CENTRAL databases were searched from inception to September 30, 2019. All studies were conducted to evaluate the correlation of lipoprotein levels and the risk and outcomes of sepsis in adult patients. The primary outcomes were the risk and mortality of sepsis.

RESULTS

Seven studies comprising 791 patients were included. Lower levels of HDL had no marked relevance with the risk of sepsis (odds radio [OR] for each 1 mg/dL increase, 0.94; 95% CI 0.86-1.02; P=0.078), whereas lower HDL levels were related to an increased mortality rate in septic patients (OR for below about median HDL levels, 2.00; 95% CI 1.23-3.24; P=0.005).

CONCLUSION

This meta-analysis did not reveal a significant association between lower HDL levels and an increase in the risk of sepsis, whereas it showed that lower HDL levels are associated with a higher mortality rate in septic adult patients. These findings suggest that HDL may be considered as a promising factor for the prevention and treatment of sepsis in the future.

U-shaped relationship of HDL and risk of infectious disease: two prospective population-based cohort studies

Aims

Preclinical evidence has indicated that HDL may play an important role in the immune system; however, very little is known about the role of HDL in the immune system in humans. We tested the hypothesis that low and high concentrations of HDL cholesterol are associated with risk of infectious disease in the general population.

Methods and results

We included 97 166 individuals from the Copenhagen General Population Study and 9387 from the Copenhagen City Heart Study with measurements of HDL cholesterol at baseline. The primary endpoint was any infectious disease requiring hospital admission, ascertained in the Danish health registries from baseline in 2003-13 or 1991-94 through 2014; 9% and 31% of individuals in the two studies experienced one or more infectious disease events. Using restricted cubic splines, there was a U-shaped association between concentrations of HDL cholesterol and risk of any infection. Following multifactorial adjustment, individuals with HDL cholesterol below 0.8 mmol/L (31 mg/dL) and above 2.6 mmol/L (100 mg/dL) had hazard ratios for any infection of 1.75 (95% confidence interval 1.31-2.34) and 1.43 (1.16-1.76), compared to those with HDL cholesterol of 2.2-2.3 mmol/L (85-95 mg/dL). In the Copenhagen City Heart Study, corresponding hazard ratios for any infection were 2.00 (1.16-3.43) and 1.13 (0.80-1.60).

Conclusion

Low and high HDL cholesterol concentrations found in 21% and 8% of individuals were associated with higher risk of infectious disease in the general population. These findings do not necessarily indicate causality.

Initial serum cholesterol level as a potential marker for post cardiac arrest patient outcomes

AIM

Cholesterol and lipoproteins have many roles during systemic inflammation in critically ill patients. Many previous studies have reported that low levels of cholesterol are associated with poor outcomes in these patients. The aim of this study was to investigate the association of initial total cholesterol with predicting neurologic outcome of post-cardiac arrest patients.

METHODS

This was a retrospective observational study of out-of-hospital-cardiac arrest (OHCA) survivors who had serum cholesterol levels at admission. Multivariate regression analysis was performed to investigate total cholesterol and its association with neurologic outcome. Area under receiver operator characteristic curve (AUROC) was assessed and cut off values for predicting good or poor neurologic outcomes were analysed.

RESULTS

A total of 355 patients were analysed. Lower total cholesterol was significantly associated with poor neurologic outcome [OR: 0.99 (95% CI: 0.98-0.99), p < 0.01] in the multivariate analysis. Cholesterol was also useful to screening for poor neurologic outcome [AUROC: 0.70 (95%CI: 0.63-0.77)]. Patients with cholesterol lower than 71 mg/dL had poor neurologic outcome with a specificity of 100%.

CONCLUSIONS

Initial cholesterol level is an easily obtained biomarker that showed association with neurologic outcomes of post cardiac arrest patients.

HDL: Fact, fiction, or function? HDL cholesterol and cardiovascular risk

The measurement of high-density lipoprotein cholesterol is highly utilized by clinicians to help predict cardiovascular risk, but this measure is not causally associated with atherosclerotic cardiovascular disease events. The use of Mendelian randomization studies has led to a change in investigative attention from the high-density lipoprotein cholesterol concentration to its physiological functions. High-density lipoprotein plays key roles in important pathways related to the development of atherosclerotic disease including reverse cholesterol transport, oxidation and inflammation, and endothelial function as well as in other physiological systems including immune system modulation, cellular apoptosis, and endothelial progenitor cell homeostasis. The identification of dysfunctional high-density lipoprotein may better predict future cardiovascular events compared to numerical high-density lipoprotein cholesterol and aid in enhanced clinical risk stratification. The emergence of discrete physiological measurements of high-density lipoprotein, such as cholesterol efflux capacity and the high-density lipoprotein inflammatory index, may provide an opportunity for clinical application in the future. However, the validity of these measurements and their commercial availability remain barriers to a realistic transition to clinical medicine.

Everything in Moderation: Investigating the U-Shaped Link Between HDL Cholesterol and Adverse Outcomes

Despite historical evidence suggesting an inverse association between HDL cholesterol (HDL-C) and adverse cardiovascular events, pharmacological efforts to increase HDL-C and improve outcomes have not been successful. Recently, a U-shaped association between HDL-C and adverse events has been demonstrated in several population cohorts, further complicating our understanding of the clinical significance of HDL. Potential explanations for this finding include genetic mutations linked to very high HDL-C, impaired HDL function at high HDL-C levels, and residual confounding. However, our understanding of this association remains premature and needs further investigation.

Role of Nutrition Support in Inflammatory Conditions

This review intends to summarize recent development on the potential nutrition implications of acute inflammation encountered during critical illness. Different aspects of the inflammatory response and their impact on nutrition management during critical illness will be discussed: the timing of the postinjury metabolic response, the integration of regulatory mechanisms involved in the metabolic response to stress, the oxidative stress, the metabolic and clinical consequences in terms of energy expenditure, use of energy, changes in body composition, and behavior.

Lipid profile associated with the systemic inflammatory response syndrome and sepsis in critically ill patients

OBJECTIVES

Changes in lipid profiles occur in systemic inflammatory response syndrome (SIRS), whether due to sepsis or another cause. Hypocholesterolemia associated with hypertriacylglycerolemia can lead to disease severity and higher mortality. The aim of this systematic review was to describe the principal alterations in markers that participate in the alteration of the lipid profile.

METHODS

We reviewed articles focused on alterations in the lipid profile in SIRS, sepsis, or both that were indexed in the Scientific Electronic Library Online from 2000 to 2017. The descriptors used were SIRS; sepsis; lipid profile; and lipoproteins. We focused in particular on the relationships among SIRS, sepsis, and lipid profiles.

RESULTS

We included 29 studies that discussed decreased high-density lipoprotein (HDL), total cholesterol, and low-density lipoprotein, and elevated triacylglycerols concentrations in patients with SIRS, sepsis, or both. The variation in the lipid profile was proportional to the level of inflammation as evaluated by inflammatory markers, including C-reactive protein, interleukin-6 and interleukin-8, lipopolysaccharide-binding protein, and tumor necrosis factor. Additionally, there was a change in the composition of lipoproteins, especially HDL, triacylglycerols, and very low-density lipoprotein. HDL appears to be an inflammatory marker, as reduction of its levels reflects the intensity of the underlying inflammatory process.

CONCLUSION

Critically ill patients with SIRS, sepsis, or both presented with alterations in lipid metabolism.

Metabolic systems analysis of LPS induced endothelial dysfunction applied to sepsis patient stratification

Endothelial dysfunction contributes to sepsis outcome. Metabolic phenotypes associated with endothelial dysfunction are not well characterised in part due to difficulties in assessing endothelial metabolism in situ. Here, we describe the construction of iEC2812, a genome scale metabolic reconstruction of endothelial cells and its application to describe metabolic changes that occur following endothelial dysfunction. Metabolic gene expression analysis of three endothelial subtypes using iEC2812 suggested their similar metabolism in culture. To mimic endothelial dysfunction, an in vitro sepsis endothelial cell culture model was established and the metabotypes associated with increased endothelial permeability and glycocalyx loss after inflammatory stimuli were quantitatively defined through metabolomics. These data and transcriptomic data were then used to parametrize iEC2812 and investigate the metabotypes of endothelial dysfunction. Glycan production and increased fatty acid metabolism accompany increased glycocalyx shedding and endothelial permeability after inflammatory stimulation. iEC2812 was then used to analyse sepsis patient plasma metabolome profiles and predict changes to endothelial derived biomarkers. These analyses revealed increased changes in glycan metabolism in sepsis non-survivors corresponding to metabolism of endothelial dysfunction in culture. The results show concordance between endothelial health and sepsis survival in particular between endothelial cell metabolism and the plasma metabolome in patients with sepsis.

Retrospective evaluation of plasma cholesterol concentration in septic dogs and its association with morbidity and mortality: 51 cases (2005-2015)

OBJECTIVE

To determine whether plasma cholesterol concentrations in dogs with sepsis is associated with morbidity or in-hospital mortality.

DESIGN

Retrospective cohort study from 2005-2015.

SETTING

Two private referral centers.

ANIMALS

Fifty-one dogs diagnosed with sepsis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Dogs were classified as septic if they displayed ≥2 criteria of the systemic inflammatory response syndrome in conjunction with a documented underlying infectious cause. Dogs were excluded if they had been diagnosed previously with any concurrent illness reported to alter plasma cholesterol concentrations. Plasma cholesterol concentrations at the time of sepsis diagnosis were statistically analyzed for association with morbidity, as measured by the presence of organ dysfunction, the number of dysfunctional organs, duration of hospitalization, cost of hospitalization, and in-hospital mortality. Twenty-eight (55%) dogs survived to discharge, 15 (29%) were euthanized during hospitalization, and 8 (16%) died despite treatment. While median cholesterol concentrations were significantly different when comparing survivors to discharge versus nonsurvivors who died naturally despite treatment (P = 0.0245), they were not significantly different when comparing survivors to all nonsurvivors (P = 0.1821). Receiver operating characteristic curve analysis showed a cholesterol cutoff of 4.5 mmol/L (174 mg/dL) with a sensitivity of 75% and a specificity of 50% for predicting in-hospital mortality. For surviving dogs, plasma cholesterol concentrations were not associated with increased length of hospital stay. Number of dysfunctional organs and plasma cholesterol concentration were the 2 most significant individual predictors for survival, and when incorporated into a multivariate logistic regression model used for prediction, the model yielded a sensitivity of 94% and specificity of 63%.

CONCLUSION

Plasma cholesterol concentration can provide prognostic information in dogs with sepsis. Further prospective studies investigating the role of cholesterol in sepsis are needed.

Association of high-density lipoprotein cholesterol with non-fatal cardiac and non-cardiac events: a CANHEART substudy

Background

Emerging evidence has questioned the role of high-density lipoprotein cholesterol (HDL-C) as an independent and modifiable risk factor for cardiovascular disease. We sought to understand the relationship between HDL-C levels and subsequent non-fatal clinical events.

Methods

Individuals without prior cardiovascular disease or cancer were identified. Outcomes of interest were classified as non-fatal cardiovascular, cancer and infectious. Sex-stratified, multivariable, cause-specific Cox proportional hazards models were created. The reference level HDL-C for both women and men was 51-60 mg/dL.

Results

Our cohort consisted of 631 762 individuals. For cardiovascular events, there was a consistent inverse relationship, with higher adjusted HRs for the lower HDL-C strata in both men and women. This relationship was also seen in the composite of non-cardiovascular outcomes. In women, the HR in the <30 mg/dL HDL-C category was 2.10 (95% CI 1.66 to 2.57) and 1.86 (95% CI 1.27 to 2.72) for cardiovascular and non-cardiovascular outcomes, respectively; in contrast, in the >90 mg/dL group, it was 0.87 (95% CI 0.74 to 1.02) and 0.81 (95% CI 0.63 to 1.06). For men, HRs were 2.02 (95% CI 1.79 to 2.28) and 1.84 (95% CI 1.47 to 2.31) in the <30 mg/dL HDL-C category for cardiovascular and non-cardiovascular outcomes, respectively, compared with 0.73 (95% CI 0.53 to 1.00) and 1.07 (95% CI 0.67 to 1.70) in the >90 mg/dL group.

Conclusions

We found an inverse relationship between HDL-C and a wide spectrum of non-fatal outcomes, suggesting that HDL-C is a heavily confounded factor that may be a marker of poor overall health, rather than an independent and modifiable risk factor.

Changes in lipid metabolism in pediatric patients with severe sepsis and septic shock

OBJECTIVES

Limited knowledge exists regarding the lipid profiles of critically ill pediatric patients with systemic inflammatory response syndrome. The aim of this study was to evaluate the relationship between the intensity of the inflammatory response and changes in the lipid profiles of critically ill pediatric patients admitted to a pediatric intensive care unit (PICU) with severe sepsis/septic shock.

METHODS

This was a prospective and observational study at a 15-bed PICU at a public university hospital. We analyzed the lipid profiles of 40 patients with severe sepsis/septic shock admitted to the PICU on the first and seventh days of hospitalization. C-reactive protein was used as a marker for systemic inflammation. Forty-two pediatric patients seen in the emergency department and without systemic inflammatory response syndrome were used to provide control values.

RESULTS

On day 1 of admission to the PICU, the patients had significantly lower levels of total cholesterol (TC), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) as well as higher concentrations of triacylglycerols compared with the control group. There was a significant increase in the TC, HDL, LDL, and apolipoprotein levels from day 1 to day 7 of the study.

CONCLUSIONS

During severe sepsis/septic shock, we found lower serum levels of lipoproteins and apolipoproteins, and these were negatively correlated with C-reactive protein. As the inflammatory response improved, the levels of TC, HDL, LDL, and apolipoproteins increased, suggesting a direct relationship between changes in the lipid profiles and inflammation.

IGF-1 may predict the severity and outcome of patients with sepsis and be associated with microRNA-1 level changes

IGF-1 functions as an anti-oxidative stress molecule and some critical patients with sepsis have a lower level of serum IGF-1. However, the association between IGF-1 and the severity or prognosis of sepsis remains unclear. This study aimed to elucidate the relationship between serum IGF-1 levels and the severity and prognosis of sepsis, and the possible mechanism was analyzed. Clinical characteristics of patients with sepsis were recorded and analyzed. Serum IGF-1 levels and micro (mi)RNA-1 levels were tested using radioimmunoassay and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis, respectively. The A549 cell line and HKC cell line were cultured in vitro and exposed to H₂O₂ with or without IGF-1 treatment. Cell death was detected by analyzing cell death markers via ELISA kits, and miRNA-1 levels were detected after H₂O₂ exposure using RT-qPCR analysis. miRNA-1 in cells was upregulated by transfection and IGF-1 mRNA was detected to determine its relationship with miRNA-1. Once again, cell ELISA kits were used to analyze cell death markers after transfection. Serum IGF-1 levels were reduced in patients with sepsis, whereas miRNA-1 levels were higher (P<0.05 vs. healthy control). Patients in the septic shock subgroup or dead patients had the lowest IGF-1 levels and the highest miRNA-1 levels (P<0.05 vs. sepsis and severe sepsis). IGF-1 levels were inversely proportional to the miRNA-1 level. In vitro, IGF-1 reduced the cell death caused by H₂O₂. miRNA-1 transfection effectively increased the sensitivity of cells to H₂O₂ damage by reducing the expression of IGF-1, which was able to prevent cells from injury caused by H₂O₂. The transfection of negative control miRNA did not influence the level of IGF-1 miRNA and the sensitivity to H₂O₂ damage. In conclusion, low IGF-1 levels in patients with sepsis may predict increased severity of the condition and poor prognosis. The possible mechanism is that the excessive miRNA-1 levels reduce IGF-1 levels, resulting in insufficient anti-oxidative action by IGF-1 which increases the injury caused by oxidative stress in patients with sepsis.

Two-year follow-up of patients with septic shock presenting with low HDL: the effect upon acute kidney injury, death and estimated glomerular filtration rate

BACKGROUND

Sepsis is associated with decreased levels of high-density lipoprotein (HDL) cholesterol. HDL has anti-inflammatory properties, and the use of Apo A-I mimetic peptides is associated with renal function improvement in animal models of sepsis. However, it is not known whether decreased HDL level results in impaired renal function in human sepsis. We investigated whether low levels of HDL conferred an increased risk of sepsis-associated acute kidney injury (AKI) or long-term decreased estimated glomerular filtration rate (eGFR) after sepsis.

METHODS

HDL concentration (mg dL^-1 ) was measured in plasma samples from 180 patients with septic shock at admission to the Emergency Department (ED). We divided the patients using median HDL as a cut-off value and assessed the frequency of sepsis-associated AKI and long-term decreased eGFR after sepsis. Univariate and multivariate analyses were performed.

RESULTS

Patients with low HDL had a significantly greater frequency of KDIGO 2 or 3 sepsis-associated AKI [39/90 (43.3%) vs. 12/90 (13.3%), P < 0.001] and decreased long-term eGFR [24/58 (41.4%) vs. 11/57 (19.3%), P = 0.018] compared to those with high HDL. The adjusted OR for sepsis-associated AKI and decreased eGFR after sepsis in the lower HDL group was 2.80 (95% CI 1.08-7.25, P = 0.033) and 5.45 (95% CI 1.57-18.93, P = 0.008), respectively.

CONCLUSION

Low HDL levels during sepsis are associated with increased risk of sepsis-associated AKI, and/or subsequent decreased eGFR. These results suggest that HDL may be involved and/or may be a marker of kidney injury during and after sepsis.

Paraoxonases and infectious diseases

The paraoxonases (PON1, PON2 and PON3) are an enzyme family with a high structural homology. All of them have lactonase activity and degrade lipid peroxides in lipoproteins and cells. As such, they play a role in protection against oxidation and inflammation. Infectious diseases are often associated with oxidative stress and an inflammatory response. Infection and inflammation trigger a cascade of reactions in the host, known as the acute-phase response. This response is associated with dramatic changes in serum proteins and lipoproteins, including a decrease in serum PON1 activity. These alterations have clinical consequences for the infected patient, including an increased risk for cardiovascular diseases, and an impaired protection against the formation of antibiotic-resistant bacterial biofilms. Several studies have investigated the value of serum PON1 measurement as a biomarker of the infection process. Low serum PON1 activities are associated with poor survival in patients with severe sepsis. In addition, preliminary studies suggest that serum PON1 concentration and/or enzyme activity may be useful as markers of acute concomitant infection in patients with an indwelling central venous catheter. Investigating the associations between paraoxonases and infectious diseases is a recent, and productive, line of research.

Similar but not the same: Differential diagnosis of HLH and sepsis

Differential diagnosis of hemophagocytic lymphohistiocytosis (HLH; hemophagocytic syndrome) and sepsis is critically important because the life-saving aggressive immunosuppressive treatment, required in the effective HLH therapy, is absent in sepsis guidelines. Moreover, HLH may be complicated by sepsis. Hyperinflammation, present in both states, gives an overlapping clinical picture including fever and performance status deterioration. The aim of this review is to provide aid in this challenging diagnostic process. Analysis of clinical features and laboratory results in multiple groups of patients (both adult and pediatric) with either HLH or sepsis allows to propose criteria differentiating these two conditions. The diagnosis of HLH is supported by hyperferritinemia, splenomegaly, marked cytopenias, hypofibrinogenemia, low CRP, characteristic cytokine profile and, only in adults, hypertriglyceridemia. In the presence of these parameters (especially the most characteristic hyperferritinemia), the other HLH criteria should be assessed. Genetic analyses can reveal familial HLH. Hemophagocytosis is neither specific nor sensitive for HLH.

Effect of inflammation on HDL structure and function

PURPOSE OF REVIEW

Studies have shown that chronic inflammatory disorders, such as rheumatoid arthritis, systemic lupus erythematosus, and psoriasis are associated with an increased risk of atherosclerotic cardiovascular disease. The mechanism by which inflammation increases cardiovascular disease is likely multifactorial but changes in HDL structure and function that occur during inflammation could play a role.

RECENT FINDINGS

HDL levels decrease with inflammation and there are marked changes in HDL-associated proteins. Serum amyloid A markedly increases whereas apolipoprotein A-I, lecithin:cholesterol acyltransferase, cholesterol ester transfer protein, paraoxonase 1, and apolipoprotein M decrease. The exact mechanism by which inflammation decreases HDL levels is not defined but decreases in apolipoprotein A-I production, increases in serum amyloid A, increases in endothelial lipase and secretory phospholipase A2 activity, and decreases in lecithin:cholesterol acyltransferase activity could all contribute. The changes in HDL induced by inflammation reduce the ability of HDL to participate in reverse cholesterol transport and protect LDL from oxidation.

SUMMARY

During inflammation multiple changes in HDL structure occur leading to alterations in HDL function. In the short term, these changes may be beneficial resulting in an increase in cholesterol in peripheral cells to improve host defense and repair but over the long term these changes may increase the risk of atherosclerosis.

The efficacy of thymosin α1 as immunomodulatory treatment for sepsis: a systematic review of randomized controlled trials

BACKGROUND

Thymosin α1 (Tα1) as immunomodulatory treatment is supposed to be beneficial for the sepsis patients by regulating T cell subsets and inflammatory mediators. However, limited by the small sample size and the poor study design, the persuasive power of the single clinical studies is weak. This meta-analysis aimed to investigate the impact of Tα1 on the sepsis patients.

METHODS

We searched for the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CBM, VIP, CNKI, WANFANG, Igaku Chuo Zasshi (ICHUSHI) and Korean literature databases reporting the effects of Tα1 on outcomes in sepsis patients.

RESULTS

Among 444 related articles, 19 randomized controlled trials (RCTs) met our inclusion criteria. Mortality events were reported in 10 RCTs included 530 patients, and the meta-analysis showed significant decrease in Tα1 group compared with control group (RR 0.59, 95 % CI 0.45 to 0.77, p = 0.0001). The subgroup analysis showed no difference between the two dosages (RR 0.59, 95 % CI 0.43 to 0.81; RR 0.59, 95 % CI 0.35 to 0.98, respectively). In 9 RCTs, with a total of 489 patients, Tα1 administered once per day decrease APACHE II score significantly (SMD -0.80, 95 % CI -1.14 to -0.47, p < 0.0001) while Tα1 twice per day showed no effect (SMD 0.30, 95 % CI-0.10 to 0.70, p = 0.14). However, the length of ICU stay, the incidence of multiple organ failure (MOF) and duration of mechanical ventilation were not significantly affected by Tα1 treatment (SMD -0.52, 95 % CI -1.06 to 0.11, p = 0.06; SMD -0.49, 95 % CI -1.09 to 0.11, p = 0.11; SMD -0.37, 95 % CI -0.90 to 0.17, p = 0.17, respectively). As to the immunological indicators, the level of HLA-DR were increased by Tα1 (SMD 1.23, 95 % CI 0.28 to 2.18, p = 0.01) according to the pooled analysis of 8 studies involving 721 patients. Lymphocyte subsets CD3, CD4 and cytokines IL-6, IL-10 and TNF-α were also beneficially affected by Tα1 treatment.

CONCLUSIONS

Tα1 may be beneficial to sepsis patients in reducing mortality and modulating inflammation reactions. However, the quality of evidence supporting the effectiveness is low considering the small sample sizes and inadequate adherence to standardized reporting guidelines for RCTs among the included studies.

HDL-c levels predict the presence of pleural effusion and the clinical outcome of community-acquired pneumonia

Objectives

To investigate if HDL cholesterol (HDL-c) could be a biomarker of the degree of severity according to prognostic prediction scores in community-acquired pneumonia (CAP) or the development of clinical complications such as pleural effusion.

Methods

We included in a retrospective study 107 patients admitted to the hospital that fulfilled diagnostic criteria for CAP between the 30th October 2011 and 1st September 2012. HDL-c levels at admission, CAP prognosis scores (PSI and CURB65) and clinical outcomes were recorded for the study.

Results

Basal HDL-c levels were not statistically different according to prognostics scores neither PSI nor CURB-65. Significantly lower levels of HDL-c were also associated to the development of septic shock and admission to the intensive care unit. HDL-c were inversely correlated with acute phase reactants CRP (r = −0.585, P < 0.001), ESR (r = −0.477, P < 0.001), and leukocytes cell count (r = −0.254, P < 0.009). Patients with pleural effusion showed significant lower levels of HDL-c [28.9 (15.5) mg/dl vs. 44.6 (21.1) mg/dl]; P = 0.007. HDL-c is a good predictor of the presence of pleural effusion in multivariate analyses and using ROC analyses [AUC = 0.712 (0.591–0.834), P = 0.006]. HDL-c levels of 10 mg/dl showed a sensitivity of 97.6 % and a specificity of 82.4 % for the presence of pleural effusion.

Conclusion

Monitoring HDL-c in CAP is an useful serum marker of acute phase response, clinical outcome and the presence of pleural effusion.

Lipid profiles of children and adolescents with inflammatory response in a paediatric emergency department

BACKGROUND

To compare the lipid profile between patients with and without inflammatory process in according nutritional status, gender and age.

METHODS

One hundred and twenty-four children and adolescents in the emergency department were separated into two groups according to the levels of C-reactive protein (CRP). Total cholesterol, high-density lipoprotein (HDL) and low-density lipoprotein (LDL), triglycerides (TG) and albumin in patients with CRP < 5 mg/L were compared with patients with CRP ≥ 5 mg/L. Nutritional status was assessed by anthropometric measurements.

RESULTS

Patients were mostly classified as well-nourished (76.5%) and had low levels of HDL (70%). There was no significant difference in lipid profile between the two groups of CRP. Linear regression analysis, however, it became clear that for each increase of 1 mg/L in the values of CRP expected an average reduction of 0.072 mg/dL of HDL, the 0.083 mg/dL of LDL, the 0.002 g/dL albumin and an average increase of 0.564 mg/dL of TG.

CONCLUSIONS

Patients with an inflammatory process exhibit changes in the serum levels of the lipids HDL, LDL and TG that are related to the degree of inflammation. These changes occurred regardless of nutritional status. Key Messages Lipoproteins are structures composed of lipids and proteins that transport fats in the circulation: HDL, LDL, IDL, VLDL and chylomicrons. Lipoproteins, especially HDL, undergo changes during the systemic inflammatory response and play an important role as a modulator of the inflammatory response. We believe this is a first study to show that inflammatory process modifies the serum levels of the lipoproteins and triglycerides independent of nutritional status, in paediatric patients.

Applied immuno-epidemiological research: an approach for integrating existing knowledge into the statistical analysis of multiple immune markers

Background

Immunologists often measure several correlated immunological markers, such as concentrations of different cytokines produced by different immune cells and/or measured under different conditions, to draw insights from complex immunological mechanisms. Although there have been recent methodological efforts to improve the statistical analysis of immunological data, a framework is still needed for the simultaneous analysis of multiple, often correlated, immune markers. This framework would allow the immunologists’ hypotheses about the underlying biological mechanisms to be integrated.

Results

We present an analytical approach for statistical analysis of correlated immune markers, such as those commonly collected in modern immuno-epidemiological studies. We demonstrate i) how to deal with interdependencies among multiple measurements of the same immune marker, ii) how to analyse association patterns among different markers, iii) how to aggregate different measures and/or markers to immunological summary scores, iv) how to model the inter-relationships among these scores, and v) how to use these scores in epidemiological association analyses. We illustrate the application of our approach to multiple cytokine measurements from 818 children enrolled in a large immuno-epidemiological study (SCAALA Salvador), which aimed to quantify the major immunological mechanisms underlying atopic diseases or asthma. We demonstrate how to aggregate systematically the information captured in multiple cytokine measurements to immunological summary scores aimed at reflecting the presumed underlying immunological mechanisms (Th1/Th2 balance and immune regulatory network). We show how these aggregated immune scores can be used as predictors in regression models with outcomes of immunological studies (e.g. specific IgE) and compare the results to those obtained by a traditional multivariate regression approach.

Conclusion

The proposed analytical approach may be especially useful to quantify complex immune responses in immuno-epidemiological studies, where investigators examine the relationship among epidemiological patterns, immune response, and disease outcomes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-016-0149-9) contains supplementary material, which is available to authorized users.

Lipid metabolism in critical illness

PURPOSE OF REVIEW

This article describes recent findings regarding lipid metabolism in critical illness as well as in lipid therapy.

RECENT FINDINGS

In critical illness, in the presence of a decrease in lipid absorption, adipose tissue lipolysis raises triglyceride levels. High-density lipoprotein and low-density lipoprotein are decreased because of impairment of lecithin-cholesterol acyltransferase, mainly in sepsis. In septic patients, lipid profile may be a predictor of survival. Nonsurvivors have lower levels of high-density lipoprotein and low-density lipoprotein. In metabolomic studies, most of the changes from baseline in septic patients were related to lipid metabolism. Lysophosphatidylcholine was also significantly lower in nonsurviving septic patients.

SUMMARY

Lipid profile results are too often neglected by the clinician despite increasing knowledge in the modifications related to septic state as well as the importance of these values in the prognosis of the critically ill. Lipid administration (enterally or parenterally) should be guided by better knowledge of the lipid metabolism of the patient.

Monocyte-induced recovery of inflammation-associated hepatocellular dysfunction in a biochip-based human liver model

Liver dysfunction is an early event in sepsis-related multi-organ failure. We here report the establishment and characterization of a microfluidically supported in vitro organoid model of the human liver sinusoid. The liver organoid is composed of vascular and hepatocyte cell layers integrating non-parenchymal cells closely reflecting tissue architecture and enables physiological cross-communication in a bio-inspired fashion. Inflammation-associated liver dysfunction was mimicked by stimulation with various agonists of toll-like receptors. TLR-stimulation induced the release of pro- and anti-inflammatory cytokines and diminished expression of endothelial VE-cadherin, hepatic MRP-2 transporter and apolipoprotein B (ApoB), resulting in an inflammation-related endothelial barrier disruption and hepatocellular dysfunction in the liver organoid. However, interaction of the liver organoid with human monocytes attenuated inflammation-related cell responses and restored MRP-2 transporter activity, ApoB expression and albumin/urea production. The cellular events observed in the liver organoid closely resembled pathophysiological responses in the well-established sepsis model of peritoneal contamination and infection (PCI) in mice and clinical observations in human sepsis. We therefore conclude that this human liver organoid model is a valuable tool to investigate sepsis-related liver dysfunction and subsequent immune cell-related tissue repair/remodeling processes.

Decreased serum concentrations of sphingosine-1-phosphate in sepsis

Introduction

Sphingosine-1-phosphate (S1P) is a signaling lipid that regulates pathophysiological processes involved in sepsis progression, including endothelial permeability, cytokine release, and vascular tone. The aim of this study was to investigate whether serum-S1P concentrations are associated with disease severity in patients with sepsis.

Methods

This single-center prospective-observational study includes 100 patients with systemic inflammatory response syndrome (SIRS) plus infection (n = 40), severe sepsis (n = 30), or septic shock (n = 30) and 214 healthy blood donors as controls. Serum-S1P was measured by mass spectrometry. Blood parameters, including C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), lactate, and white blood cells (WBCs), were determined by routine assays. The Sequential Organ Failure Assessment (SOFA) score was generated and used to evaluate disease severity.

Results

Serum-S1P concentrations were lower in patients than in controls (P < 0.01), and the greatest difference was between the control and the septic shock groups (P < 0.01). Serum-S1P levels were inversely correlated with disease severity as determined by the SOFA score (P < 0.01) as well as with IL-6, PCT, CRP, creatinine, lactate, and fluid balance. A receiver operating characteristic analysis for the presence or absence of septic shock revealed equally high sensitivity and specificity for S1P compared with the SOFA score. In a multivariate logistic regression model calculated for prediction of septic shock, S1P emerged as the strongest predictor (P < 0.001).

Conclusions

In patients with sepsis, serum-S1P levels are dramatically decreased and are inversely associated with disease severity. Since S1P is a potent regulator of endothelial integrity, low S1P levels may contribute to capillary leakage, impaired tissue perfusion, and organ failure in sepsis.

Correlation of urine and plasma cytokine levels among reproductive-aged women

BACKGROUND

Inflammation is implicated in many adverse health conditions, and recent interest has focused on the effects of chronic low-grade inflammation in generally healthy populations. Cytokines measured in plasma or serum are commonly used as biomarkers of systemic levels of inflammation. Measurement of cytokines in urine may offer a simpler and less invasive alternative, although the degree to which levels of cytokines correlate in plasma and urine among healthy individuals is unknown.

MATERIALS AND METHODS

We assessed the correlation of blood and urine levels of 13 cytokines, including interleukin (IL)-1b, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12(p70) and IL-13, granulocyte macrophage colony-stimulating factor, interferon gamma and tumour necrosis factor alpha in 61 healthy women aged 18-30. Cytokine concentrations were considered with and without correction for creatinine.

RESULTS

Plasma and urine levels of the 13 cytokines were not significantly correlated using measured urinary cytokine concentrations and after adjustment for creatinine. Correlation coefficients for log-transformed cytokine concentrations in paired plasma and urine specimens ranged from -0.28 to 0.087.

CONCLUSIONS

These results suggest that urine has limited utility as a proxy for plasma for the measurement of inflammatory factors in a healthy population with low levels of inflammation.

Biomarkers in critically ill patients with systemic inflammatory response syndrome or sepsis supplemented with high-dose selenium

OBJECTIVE

Low levels of selenium (Se) and glutathione peroxidase (GSHPx), a key selenoenzyme, were documented in systemic inflammatory response syndrome (SIRS) and sepsis, both associated with high mortality. Se supplementation had mixed effects on outcome. We hypothesized that Se supplementation could have a different impact on biomarkers and 28-day mortality in patients with SIRS vs. sepsis.

METHODS

Adult patients with SIRS or sepsis were randomized to either high-dose (Se+, n = 75) or standard-dose (Se-, n = 75) Se supplementation. Plasma Se, whole blood GSHPx activity, C-reactive protein (CRP), procalcitonin (PCT), prealbumin, albumin and cholesterol levels were measured serially up to day 14.

RESULTS

There was no difference in mortality between Se- (24/75) vs. Se+ group (19/75; p = 0.367) or between SIRS and septic patients (8/26 vs. 35/124; p = 0.794). There was a trend to reduced mortality in SIRS patients in the Se+ vs. Se- group (p = 0.084). Plasma Se levels increased in the Se+ group only in patients with sepsis but not in patients with SIRS. Plasma Se levels correlated with GSHPx. In SIRS/Se+ group, Se correlated only with GSHPx. In SIRS/Se- group, Se correlated with cholesterol but not with other biomarkers. In sepsis patients, Se levels correlated with cholesterol, GSHPx and prealbumin. Cholesterol levels were higher in survivors in the Se- group.

CONCLUSIONS

Se levels correlated with GSHPx activity and other nutritional biomarkers with significant differences between SIRS and sepsis groups. High-dose Se supplementation did not affect mortality but a strong trend to decreased mortality in SIRS patients warrants further studies in this population.

Moxifloxacin-loaded nanoemulsions having tocopheryl succinate as the integral component improves pharmacokinetics and enhances survival in E. coli-induced complicated intra-abdominal infection

In the present work, a novel nanoemulsion laden with moxifloxacin has been developed for effective management of complicated intra-abdominal infections. Moxifloxacin nanoemulsion fabricated using high pressure homogenization was evaluated for various pharmaceutical parameters, pharmacokinetics (PK) and pharmacodynamics (PD) in rats with E. coli-induced peritonitis and sepsis. The developed nanoemulsion MONe6 (size 168 ± 28 nm and zeta potential (ZP) 24.78 ± 0.45 mV, respectively) was effective for intracellular delivery and sustaining the release of MOX. MONe6 demonstrated improved plasma (AUC(MONe6/MOX) = 2.38-fold) and tissue pharmacokinetics of MOX (AUC(MONe6/MOX) = 2.63 and 1.47 times in lung and liver, respectively). Calculated PK/PD index correlated well with a reduction in bacterial burden in plasma as well as tissues. Enhanced survival on treatment with MONe6 (65.44%) and as compared to the control group (8.22%) was a result of reduction in lipid peroxidation, neutrophil migration, and cytokine levels (TNF-α and IL6) as compared to untreated groups in the rat model of E. coli-induced sepsis. Parenteral nanoemulsions of MOX hold a promising advantage in the therapy of E. coli-induced complicated intra-abdominal infections and is helpful in the prevention of further complications like septic shock and death.