IntroductionSphingosine-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.MethodsThis 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.ResultsSerum-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).ConclusionsIn 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.

Background and ObjectivesAtherosclerotic changes of arteries are the leading cause for deaths in cardiovascular disease and greatly impair patient’s quality of life. Sphingosine-1-phosphate (S1P) is a signaling sphingolipid that regulates potentially pro-as well as anti-atherogenic processes. Here, we investigate whether serum-S1P concentrations are associated with peripheral artery disease (PAD) and carotid stenosis (CS).Methods and ResultsSerum was sampled from blood donors (controls, N = 174) and from atherosclerotic patients (N = 132) who presented to the hospital with either clinically relevant PAD (N = 102) or CS (N = 30). From all subjects, serum-S1P was measured by mass spectrometry and blood parameters were determined by routine laboratory assays. When compared to controls, atherosclerotic patients before invasive treatment to restore blood flow showed significantly lower serum-S1P levels. This difference cannot be explained by risk factors for atherosclerosis (old age, male gender, hypertension, hypercholesteremia, obesity, diabetes or smoking) or comorbidities (Chronic obstructive pulmonary disease, kidney insufficiency or arrhythmia). Receiver operating characteristic curves suggest that S1P has more power to indicate atherosclerosis (PAD and CS) than high density lipoprotein-cholesterol (HDL-C). In 35 patients, serum-S1P was measured again between one and six months after treatment. In this group, serum-S1P concentrations rose after treatment independent of whether patients had PAD or CS, or whether they underwent open or endovascular surgery. Post-treatment S1P levels were highly associated to platelet numbers measured pre-treatment.ConclusionsOur study shows that PAD and CS in humans is associated with decreased serum-S1P concentrations and that S1P may possess higher accuracy to indicate these diseases than HDL-C.

Critical Care 2017, 21(Suppl 1):P349 Introduction Imbalance in cellular energetics has been suggested to be an important mechanism for organ failure in sepsis and septic shock. We hypothesized that such energy imbalance would either be caused by metabolic changes leading to decreased energy production or by increased energy consumption. Thus, we set out to investigate if mitochondrial dysfunction or decreased energy consumption alters cellular metabolism in muscle tissue in experimental sepsis. Methods We submitted anesthetized piglets to sepsis (n = 12) or placebo (n = 4) and monitored them for 3 hours. Plasma lactate and markers of organ failure were measured hourly, as was muscle metabolism by microdialysis. Energy consumption was intervened locally by infusing ouabain through one microdialysis catheter to block major energy expenditure of the cells, by inhibiting the major energy consuming enzyme, N+/K + -ATPase. Similarly, energy production was blocked infusing sodium cyanide (NaCN), in a different region, to block the cytochrome oxidase in muscle tissue mitochondria. Results All animals submitted to sepsis fulfilled sepsis criteria as defined in Sepsis-3, whereas no animals in the placebo group did. Muscle glucose decreased during sepsis independently of N+/K + -ATPase or cytochrome oxidase blockade. Muscle lactate did not increase during sepsis in naïve metabolism. However, during cytochrome oxidase blockade, there was an increase in muscle lactate that was further accentuated during sepsis. Muscle pyruvate did not decrease during sepsis in naïve metabolism. During cytochrome oxidase blockade, there was a decrease in muscle pyruvate, independently of sepsis. Lactate to pyruvate ratio increased during sepsis and was further accentuated during cytochrome oxidase blockade. Muscle glycerol increased during sepsis and decreased slightly without sepsis regardless of N+/K + -ATPase or cytochrome oxidase blocking. There were no significant changes in muscle glutamate or urea during sepsis in absence/presence of N+/K + -ATPase or cytochrome oxidase blockade. ConclusionsThese results indicate increased metabolism of energy substrates in muscle tissue in experimental sepsis. Our results do not indicate presence of energy depletion or mitochondrial dysfunction in muscle and should similar physiologic situation be present in other tissues, other mechanisms of organ failure must be considered. , and long-term follow up has shown increased fracture risk [2]. It is unclear if these changes are a consequence of acute critical illness, or reduced activity afterwards. Bone health assessment during critical illness is challenging, and direct bone strength measurement is not possible. We used a rodent sepsis model to test the hypothesis that critical illness causes early reduction in bone strength and changes in bone architecture. Methods 20 Sprague-Dawley rats (350 ± 15.8g) were anesthetised and randomised to receive cecal ligation and puncture (CLP) (50% cecum length, 18G needle single pass through anterior and posterior wa...