Hypoxia induces apelin expression in human adipocytes.

Adipokines play a central role in the development of diseases associated with insulin resistance and obesity. Hypoxia in adipose tissue leads to a dysregulation of the expression of adipokines. The effect of hypoxia on the more recently identified adipokine apelin in human adipocytes is unclear. Therefore, we aimed at investigating the role of hypoxia on the expression of the adipokine apelin. Differentiated human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes were cultured under hypoxic conditions for varying time periods. A modular incubator chamber was used to create a hypoxic tissue culture environment (defined as 1% O(2), 94% N, and 5% CO(2)). In addition, hypoxic conditions were mimicked by using CoCl(2). The effect of hypoxia on the expression of the investigated adipokines was measured by real-time PCR and the secretion of apelin was quantified by ELISA. Induction of hypoxia significantly induced mRNA expression of leptin and apelin in differentiated SGBS adipocytes compared with the normoxic control condition. Expression of adiponectin was significantly decreased by hypoxia. In addition, the amount of secreted apelin protein in response to hypoxia was elevated compared to untreated cells. Furthermore, we could demonstrate that the observed hypoxia-induced induction of apelin mRNA expression is in the first phase dependent on HIF-1α. In our study, we could demonstrate for the first time that apelin expression and secretion by human adipocytes are strongly induced under hypoxic conditions and that the early response on hypoxia with apelin induction is dependent on HIF-1α.

Serum IgG levels and mortality in patients with severe sepsis and septic shock : The SBITS data.

BACKGROUND: The role of intravenous immune globulin (Ig) therapy in patients with severe sepsis and septic shock is discussed controversially. Low initial IgG levels could help to identify those patients who might benefit from an adjunctive Ig treatment. OBJECTIVES: To investigate the effect of initial serum IgG levels on 28-day mortality in patients with severe sepsis and septic shock. MATERIALS AND METHODS: In this retrospective analysis of the SBITS trial data, 543 patients were allocated to four groups (quartiles) depending on their initial serum IgG levels (1: IgG ≤ 6.1 g/l; 2: IgG 6.2-8.4 g/l; 3: IgG 8.5-11.9 g/l; 4: IgG > 11.9 g/l). The third quartile was taken as the reference quartile. For the applied logistic regression model clinically relevant confounders were defined and integrated into further risk-adjusted calculations. RESULTS: Patients with the lowest IgG levels had a mortality rate similar to those patients with initial IgG levels in the second and third quartile, representing the physiological IgG range in healthy people. Surprisingly, patients with the highest IgG levels even showed a significantly higher mortality in a risk-adjusted calculation compared to the reference quartile (OR 1.69, CI 1.01-2.81, p = 0.05). Subgroup analyses revealed that initial IgG levels were of no prognostic value in patients presenting with vasopressor-dependent septic shock on admission as well as in patients with either gram-positive or gram-negative sepsis. CONCLUSIONS: Initially low IgG levels do not discriminate between survival and nonsurvival in patients with severe sepsis and septic shock. Therefore, low IgG cannot help to identify those patients who might benefit from an adjunctive IgG sepsis therapy. Whether a high initial IgG serum level is an independent mortality risk factor needs to be investigated prospectively.

Modulation of coronary vasomotor tone by cytokines in cardiac transplant recipients.

BACKGROUND: Upon exposure to cytokines, endothelial cells may undergo profound alterations of vasomotor function. In this study, we characterized the relationship between coronary epicardial and microvascular vasomotor function and expression of specific cytokine patterns in human heart transplant recipients. METHODS: We studied 49 cardiac transplant recipients, without acute rejection or infection at an average of 6+/-3 months after transplantation. Coronary resistance vessel function was measured in an endothelium-dependent manner with acetylcholine (5 and 150 microg/5 min; intracoronary injection) and in an endothelium-independent manner with adenosine (400 and 800 microg/5 min; intracoronary injection) using an intracoronary Doppler flow wire. Simultaneous epicardial diameter changes were measured using quantitative coronary angiography. Coronary sinus and aortic serum levels of soluble interleukin (IL)-2 receptor and soluble tumor necrosis factor-a receptors (sTNF-R1 and sTNF-R2), TNF-alpha, and IL-6 were determined. Transcardiac cytokine release (coronary sinus minus aortic levels) was correlated with coronary vasomotor function. RESULTS: The highest amounts of cardiac cytokine release were observed for IL-6 (32+/-14% increase) and sTNF-R1 (26+/-13% increase). A significant inverse correlation between microvascular endothelial function and cardiac release of soluble IL-2 receptor (P=0.04) and IL-6 (P=0.03) was detected, whereas a positive correlation was observed to sTNF-R1 (P=0.004). Distal epicardial endothelial vasomotion was inversely correlated to transcardiac sTNF-R2 release (P=0.03). CONCLUSIONS: Cytokine production and activation, a common phenomenon early after heart transplantation, is related at least in part to endothelial vasomotor dysfunction of the epicardial and microvascular compartment. These results support the hypothesis that coronary endothelial dysfunction after cardiac transplantation is an immunologic phenomenon. Since endothelial dysfunction seems to be a crucial step in the pathogenesis of cardiac allograft vasculopathy, coronary cytokine suppression should be a therapeutic target of improved future immunosuppressive regimens.

Association of serum tumor necrosis factor levels with decrease of cholesterol during septic shock.

Recent studies suggest that release of cytokines during inflammatory states such as septic shock leads to hypocholesterolemia. To examine whether tumor necrosis factor alpha (TNF), which is the major cytokine in inflammatory disease, causes hypocholesterolemia, we measured serum levels of total (bioactive and receptor-bound) TNF, cholesterol, Apo B, and Apo A1 in seven patients with septic shock over a period of 8 days. Since elevated serum TNF levels are accompanied by the release of soluble TNF receptors, levels of TNF receptors p55 and p75 were also measured. Patients with septic shock had significantly higher serum TNF and TNF receptor levels compared with healthy controls. Increased cytokine levels were accompanied by a significant decline in total serum cholesterol apolipoprotein A1 and B. In vitro studies with cultured human skin fibroblasts, human umbilical vein endothelial cells, and HepG2 hepatoma cells showed that TNF increased the degradation of 125I-labeled low-density lipoprotein in all the cell lines tested. Recombinant soluble TNF receptors inhibited the TNF-induced stimulation of low-density lipoprotein receptor in a concentration-dependent manner. However, the calculated ratio of TNF receptors to total TNF measured in serum of these patients was not able to counteract the stimulatory effect of TNF, possibly due to the higher molar excess of TNF receptors required to achieve this effect in vitro. Our data strengthen the hypothesis that serum values of total TNF determine the extent of hypocholesterolemia during sepsis and septic shock despite the presence of a high concentration of TNF receptors. Studies with recombinant TNF also confirm the role of TNF in hypocholesterolemia in inflammation.

Cytokine production precedes the expansion of CD14+CD16+ monocytes in human sepsis: a case report of a patient with self-induced septicemia.

We describe a patient with self-induced disease who presented with repeated urinary tract infection and sepsis due to intravesical and intravenous injection of feces. Sepsis occurred repeatedly such that the patient exhibited 10 bouts of fever > 40 degrees C in a single month. This bacterial challenge led to massive activation of the monocyte system with high levels of TNF-alpha, IL-6, and monocyte colony-stimulating factor (M-CSF). This cytokine response was followed by strong expansion of the novel CD14+CD16+ monocyte subset. These results suggest that cytokines induce the development of CD14+CD16+ cells in human septicemia and that CD14+CD16+ cells may serve as indicator for previous bouts of excessive inflammation.

Modulation of immune response by blood transfusion: evidence for a differential effect of allogeneic and autologous blood in colorectal cancer surgery.

Even though blood transfusion-associated immunomodulatory effects have been reported, the basic immune mechanism is still not understood. Data from studies on the clinical effects of allogeneic blood-induced immunosuppression are contradictory. However, there are indications that autologous blood transfusion is not immunologically neutral but has intrinsic immunomodulatory potential. Therefore we investigated in vivo different immunological mediators in 56 randomized patients of a study comparing autologous and allogeneic blood transfusion in colorectal cancer surgery. Soluble IL-2 receptor, which is an indicator of general immune activation and the following immunologic refractory phase, indicated immunosuppression was more elevated at the seventh postoperative day in patients with allogeneic transfusions (p = .013) and autologous transfusions (p = .0003). The immunologic determination of TNF-alpha showed a significant postoperative increase in patients with autologous transfusions only (p = .0031). However, postoperative increase of soluble TNF-receptors p55 and p75 was also significant in patients transfused with allogenic blood (p = .022; p = .0014). The response to tetanus toxoid vaccination, an indicator of humoral immunity, was higher in patients transfused with allogeneic rather than autologous blood (p = .082), whereas responses of patients with autologous transfusions were even lower than in nontransfused patients. The reciprocal was already found for cell-mediated immunity determined by epicutaneously tested delayed-type hypersensitivity-reactions. IL-10 levels, an indicator of cellular immunosuppression, were determined in 27 additional patients before operation, immediately postoperative, and at the seventh postoperative day. IL-10 was found elevated immediately postoperative in allogeneic (p = .011) and nontransfused patients only (p = .042). The data from this study substantiate recent findings of a different immunomodulatory potential of allogeneic and autologous blood transfusion. They furthermore support the hypothesis that autologous blood transfusion does not contain immunologically neutral effects of allogeneic blood, but itself exerts an immunomodulatory effect.

Procalcitonin: a new marker for diagnosis of acute rejection and bacterial infection in patients after heart and lung transplantation.

UNLABELLED: The aim of the study was to investigate the reliability of procalcitonin (PCT), a new potential marker for detection of bacterial, fungal and protozoal infections, in order to differentiate these from viral infections and early rejections in heart, heart-lung and lung transplanted patients. PCT is a propeptide of calcitonin with unknown origin which is not detectable in plasma of healthy subjects. It increases rapidly and significantly under severe microbial infections. METHODS: PCT plasma levels were measured using an immuno-luminescence assay. C-reactive protein and white blood cells were quantified to validate the PCT values. RESULTS: Increased levels of PCT were found in all transplant patients with bacterial, fungal and protozoal infections. The magnitude of the values were clearly associated with the severity of the infection. Trauma of operation or inflammatory events such as viral infections and rejections did not trigger PCT-production. The release of PCT did not depend on the type of pathogens even though Aspergillum resulted in the highest levels measured. Sensitivity, specificity and prognostic value of PCT for systemic infections were higher than of the other parameters investigated. CONCLUSION: PCT is a highly specific analyte which shows significant diagnostic validities when nonviral infections are compared with rejection episodes. PCT discriminates between inflammatory events such as rejection or viral infections and nonviral-infections including bacterial, fungal and protozoal infections. The half-life of PCT is 24 h indicating clearly a competent antibiotic treatment. Unnecessary antibiotic therapy can be avoided due to the early exclusion of bacterial and fungal infections.

Inflammatory reactions induced by pretransplant conditioning--an alternative target for modulation of acute GvHD and complications following allogeneic bone marrow transplantation?

Intensity of pretransplant conditioning has been closely correlated with regimen related toxicity in patients receiving allogeneic bone marrow transplantation (BMT). In this review, we summarize evidence for a direct link between inflammatory reactions induced by irradiation and cytotoxic treatment and occurrence of acute graft-versus-host disease (GvHD) as well as endothelial complications: In our studies, de novo release of TNFalpha during conditioning was associated with an increased risk of severe GvHD and mortality following BMT, whereas increased spontaneous production of IL-10, an endogenous TNF-antagonist, prior to conditioning protected from these complications. Immunogenetic differences in cytokine regulation and costimulation by endotoxin proved to be important cofactors determining the extent of inflammatory cytokine release in individual patients. Pathophysiological relevance of these findings seems to be confirmed by experimental as well as first clinical trials using TNF-antibodies and related antagonists during pretransplant conditioning. Preclinical experiments suggest additional, cytokine independent inflammatory reactions induced by irradiation such as expression of ICAM-1 and endothelial cell apoptosis. Although the exact impact of these findings on pathophysiology of BMT related complications needs further clarification by future studies, conditioning related inflammation as a first crucial step in induction of GvHD and complications has to be considered when designing new protocols for preparation of patients for allogeneic BMT.

Corticosteroid-binding globulin and free cortisol in the early postoperative period after cardiac surgery.

OBJECTIVES: To characterize concentrations of corticosteroid-binding globulin (CBG), total and free serum cortisol, and free urinary cortisol in patients during the postoperative period of cardiac surgery. DESIGN AND METHODS: In 24 patients serum was sampled on the first and second postoperative day after cardiac surgery (21 procedures with thoracotomy, 3 thoracoscopic procedures); urine was collected for two 10-h periods (8 P.M. until 6 A.M.) on the respective postoperative days. Total serum cortisol and free urinary cortisol were measured with an automated chemiluminescence assay (analysis of urine after extraction with dichloromethane), and CBG using a coated-tube RIA. Free serum cortisol was calculated from the concentrations of total serum cortisol and CBG as described previously. Thirty healthy volunteers were studied as controls. RESULTS: CBG was reduced to about one-half of the normal concentration on both postoperative days. Whereas total cortisol was about two-fold increased on the first postoperative day compared to controls extremely high concentrations of free serum cortisol were calculated from CBG and total cortisol [median 136 nmol/L (interquartile range 100-185); controls 21.8 nmol/L (interquartile range 16.9-29.8)]. On the second postoperative day, median total serum cortisol was within the interquartile range of the controls, free serum cortisol in contrast was still two-fold increased. Free serum cortisol and free urinary cortisol were significantly correlated (r = 0.60). CONCLUSIONS: Extremely high concentrations of free serum cortisol are typically found in the postoperative period of cardiac surgery; under these conditions the mere consideration of total cortisol does not appropriately display the activation of the adrenal cortex.

Lack of an association of urinary albumin excretion with interleukin-6 or C-reactive protein in patients with type 2 diabetes.

The reason for the elevation of fibrinogen concentration in diabetic patients with nephropathy is not known so far. In order to elucidate the mechanism of such an increase in fibrinogen levels, we investigated haemorheological and inflammatory markers in type 2 diabetic patients in a cross-sectional design. Thirty-two non-smoking type 2 diabetic patients (13 women, 19 men; body mass index 29.1+/-5.4 kg/m2, age 62.8+/-12.1 years) were investigated. Patients with C-reactive protein levels >1.5 mg/dl were excluded from the study. Concentration of fibrinogen was measured by immunonephelometry, C-reactive protein by immunoturbidimetry, and interleukin-6 (IL-6) by an enzyme-linked immunosorbent assay, and viscosity of plasma and of whole blood was determined by rotation viscosimetry. Concentrations of inflammatory parameters were well correlated with each other (p<0.05 for all correlations): IL-6 with C-reactive protein (r=0.48), and C-reactive protein with fibrinogen (r=0.41). While no associations were found with concentrations of C-reactive protein or IL-6, urinary albumin excretion was correlated with erythrocyte sedimentation rate (r=0.47) and with fibrinogen concentration (r=0.39; p<0.05). In patients with type 2 diabetes mellitus, urinary albumin excretion was not associated with concentrations of IL-6 or C-reactive protein. These results suggest an IL-6-independent mechanism for increased fibrinogen levels and erythrocyte sedimentation rate in type 2 diabetic patients with increased urinary albumin excretion.

Expansion of CD14+CD16+ monocytes in critically ill cardiac surgery patients.

We have asked whether critically ill cardiac valve surgery patients identified by a high APACHE II score exhibit an increase in the number of proinflammatory CD14+CD16+ monocytes. A group of 12 patients was studied over a period of 5 days post cardiac valve surgery for changes in blood monocyte populations. Patients were selected on day 1 post surgery to either be in good clinical condition (APACHE II Score of < or = 14; N = 9) or to be critically ill (APACHE II score of > or = 24; N = 3). The < or = 14 patients had an uneventful course and could leave the ICU after 2-3 days. Among the > or = 24 patients two showed a decrease of the score to < or = 14 within the 5 days of observation and they could leave the ICU thereafter. One > or = 24 patient (patient #2) had a persistently high score and finally died on day 28. Analysis of blood monocytes on day 1 post surgery revealed that the < or = 14 patients had normal values of CD14+CD16+ monocytes (44 +/- 9/microliter). By contrast the > or = 24 patients had increased values of these cells with 243 +/- 106 cells per microliter on day 1. The numbers of CD14+CD16+ monocytes returned to the control range over the 5 days of observation in 2 of the > or = 24 patients concomitant with the improvement of the APACHE II score. CD14+CD16+ monocytes remained, however, at a high level in patient #2, the patient with persistently high APACHE II score.

Procalcitonin, a new indicator for non-viral infections in heart, lung or liver transplant patients.

PCT is a highly specific analyse which shows significant diagnostic validities when non-viral infections are compared with rejection episodes. PCT discriminates inflammatory events such as rejection or viral infections and non-viral infections including bacterial, fungal and protozoal infections. The half-life of PCT is 24 h indicating a clearly competent antibiotic treatment. PCT provides vital information early to clinicians and allows them to improve the management of bacterial/fungal infection in immunocompromised transplant patients. PCT thus facilitates and improves the outcome of survival rate and the quality of life in the postoperative period of patients with heart, lung or liver grafts.

[Pathophysiology of sepsis and possible influence of statins]. / Pathophysiologie der Sepsis und deren mögliche Beeinflussung durch HMG-CoA-Reduktase-Inhibitoren.

Severe sepsis and septic shock are common complications in the intensive care unit and associated with high mortality. Early antimicrobial therapies together with organ-supportive measures are the major therapeutic approaches. However in the last decades immunomodulatory therapies have been investigated due to the notion of a compromised inflammatory response in septic patients. In addition to lowering circulating cholesterol, statins (HMG-CoA-reductase-inhibitors) have also been shown to possess pleiotropic anti-inflammatory potential. Recent studies indicate that these anti-inflammatory effects also modulate acute inflammatory response and therefore may play a protective role in septic patients. In this review, the pathophysiological background and first clinical trials of statins as a new adjuvant therapy in sepsis are summarized.

Evaluation of the ADVIA Centaur TSH-3 assay.

An analytical evaluation of the thyroid stimulating hormone (TSH-3) assay on the Bayer ADVIA Centaur immunoassay system was performed. General analytical requirements (linearity, resistance to typical interferences, absence of a carry-over effect) were fulfilled and reproducibility was satisfactory. Inter-assay coefficient of variation (CV) of a human serum pool with a concentration of 0.014 mU/l was 22.3%; at concentrations between 0.26 and 83 mU/l CV was below 6%. Method comparison study demonstrated close agreement of TSH results compared to those obtained with the Roche Elecsys 2010 TSH assay (ADVIA Centaur = 1.08 x Elecsys - 0.18 mU/l; r=0.987; n=324). Handling and practicability of the ADVIA Centaur system proved to be convenient with a very high sample throughput. We conclude that the ADVIA Centaur TSH-3 assay meets requirements for clinical use.

[Significance of the heart-lung machine for the concept of minimal invasive heart surgery]. / Bedeutung der Herz-Lungen-Maschine für das Konzept der minimal-invasiven Herzchirurgie.

Proinflammatory cytokines have been implicated in mediating myocardial dysfunction in a systemic inflammatory reaction following open heart surgery with extracorporeal circulation (ECC). The present study aimed to distinguish the surgical impact on cytokine release from the influence of ECC in a model of supported angioplasty. The extracorporeal circulation and not surgical trauma was found to be the main trigger of the systemic inflammatory response.

Procalcitonin for differential diagnosis of graft rejection and infection in patients with heart and/or lung grafts.

OBJECTIVES: Investigation of the reliability of Procalcitonin (PCT) for differential diagnosis of acute rejections and non-viral infections in heart and lung transplanted patients. DESIGN: Retrospective study. SETTING: Transplant intensive care unit (ICU) at a university hospital. PATIENTS: 57 heart, 18 lung and 3 heart-lung transplant patients. MEASUREMENTS: PCT was measured in plasma samples of heart and lung transplanted patients using a commercial immuno-luminescence assay and was compared with values of C-reactive protein (CRP) and leukocytes (WBC). RESULTS: PCT was elevated in patients suffering from bacterial and fungal infections. The magnitude of values was clearly associated with the severity of the infection. Rejections and viral infections did not interfere with the PCT release. CONCLUSION: PCT is a reliable predictor with discriminating power for non-viral systemic infections in patients after heart and/or lung transplantation. PCT allows an early differential diagnosis between rejection (AR) and bacterial/fungal infection (IF) and thus a rapid and focused therapeutic intervention. It avoids unnecessary antibiotic treatment which could be toxic for the graft itself in patients with rejection only. PCT provides vital information early to clinicians and allows them to improve the management of bacterial/fungal infections in immunocompromized transplant patients. PCT thus facilitates and improves the outcome of survival rate and the quality of life in the postoperative period of patients with heart and/or lung grafts.

Early prediction of outcome in score-identified, postcardiac surgical patients at high risk for sepsis, using soluble tumor necrosis factor receptor-p55 concentrations.

OBJECTIVE: To investigate the prognostic value of increased serum concentrations of soluble tumor necrosis factor (TNF) receptors in patients at high risk for sepsis. DESIGN: Prospective study. SETTING: Cardiac surgical intensive care unit in a University Hospital. PATIENTS: Those 27 of 870 consecutive postcardiac surgical patients who met a previously validated high-risk criterion for imminent sepsis (Acute Physiology and Chronic Health Evaluation II [APACHE II] score of > or = 24 on the first postoperative day [day 1]). In this population, systemic inflammatory response syndrome was present in 96% of the patients and the in-hospital mortality rate was 30%. In addition, ten postcardiac surgical patients with an uncomplicated course (mortality rate 0%) were studied for comparison. INTERVENTIONS: Blood sampling for measurements of serum concentrations of TNF and soluble TNF receptors 55 kilodalton (TNF receptor-p55) and 75 kilodalton (TNF receptor-p75) on days 1, 2, 3, and 5. MEASUREMENTS AND MAIN RESULTS: Compared with the ten patients with an uncomplicated course (group A), the high-risk patients had significantly higher baseline (day 1) serum concentrations of soluble TNF receptor-p55 (9.2 vs. 4.2 ng/mL) and soluble TNF receptor-p75 (9.2 vs. 5.5 ng/mL). These high-risk patients could be further differentiated into two subgroups: one (B) with a prompt decrease in APACHE II score and a good prognosis (mortality rate 0%) and another (C) with a persisting high risk of sepsis and mortality rate (40%, p < .05). Although baseline APACHE II score was similar in both high-risk subgroups, soluble TNF receptor-p55 concentrations were significantly higher in subgroup C compared with subgroup B already at baseline (10.7 vs. 4.7 ng/mL). The receiver operating characteristic curve for subgroup classification by soluble TNF receptor-p55 was in a discriminating position with an area (0.773 +/- 0.096), confirming soluble TNF receptor-p55 as a predictor of mortality. TNF and soluble TNF receptor-p75 concentrations were less predictive at baseline. CONCLUSIONS: This study suggest that increased soluble TNF receptor-p55 concentrations in the serum of postcardiac surgical patients allow earlier prognostication of subsequent hospital course than APACHE II scores alone. This study further suggests that the combination of physiologic scores and cytokine receptor measurements could improve the predictive power of early postoperative risk stratification.

Reduction of circulating cholesterol and apolipoprotein levels during sepsis.

Sepsis with multiple organ failure is frequently associated with a substantial decrease of cholesterol levels. This decrease of cholesterol is strongly associated with mortality suggesting a direct relation between inflammatory conditions and altered cholesterol homeostasis. The host response during sepsis is mediated by cytokines and growth factors, which are capable of influencing lipid metabolism. Conversely lipoproteins are also capable of modulating cytokine production during the inflammatory response. Therefore the decrease in circulating cholesterol levels seems to play a crucial role in the pathophysiology of sepsis. In this review the interaction between cytokines and lipid metabolism and its clinical consequences will be discussed.