Circulating levels of macrophage migration inhibitory factor are associated with mild pulmonary dysfunction after cardiopulmonary bypass

Impact of Steroid on Macrophage Migration Inhibitory Factor During and After Cardiopulmonary Bypass

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine released in response to glucocorticoids, which counter-regulates the effects of glucocorticoids. This study was performed to determine the impact of steroids on the expression of MIF and other pro- and anti-inflammatory cytokines during and after cardiopulmonary bypass (CPB). Twenty adult patients (10 men, 64 ± 8 years old) who underwent elective cardiac surgery by CPB were given either 2000 mg (group-H, n = 10) or 500 mg of methylprednisolone (group-L, n = 10) during CPB. The serum concentrations of MIF, interleukin (IL)-1β, IL-8, IL-10, and tumor necrosis factor-alpha (TNF-α) were measured at eight time points until 36 hours after skin closure. The early postoperative course was uneventful for all patients. There were no significant differences in duration of operation, CPB, or aortic cross-clamping (AXC) between the two groups. MIF and IL-10 levels peaked just after the conclusion of CPB and decreased gradually thereafter. IL-1β, IL-8, and TNF-α were undetectable throughout the study period. There were no significant differences in MIF or IL-10 levels between the two groups. Peak levels of MIF in all patients were significantly correlated with the duration of CPB and AXC, whereas no such correlation was observed for IL-10. MIF or IL-10 levels were significantly elevated during and after CPB, but there were no differences between the two doses of steroid administration. Both steroid doses sufficiently suppressed proinflammatory cytokines. MIF better reflected the invasiveness of the operation than IL-10.

Effect of 6% Hydroxyethyl Starch 130/0.4 on Inflammatory Response and Pulmonary Function in Patients Having Cardiac Surgery: A Randomized Clinical Trial

BACKGROUND

Cardiac surgery with cardiopulmonary bypass induces a profound inflammatory response that, when severe, can lead to multiorgan system dysfunction. Preliminary data suggest that administration of hydroxyethyl starch (HES) solutions may mitigate an inflammatory response and improve pulmonary function. Our goal was to examine the effect of 6% HES 130/0.4 versus 5% human albumin given for intravascular plasma volume replacement on the perioperative inflammatory response and pulmonary function in patients undergoing cardiac surgery.

METHODS

This was a subinvestigation of a blinded, parallel-group, randomized clinical trial of patients undergoing elective aortic valve replacement surgery at the Cleveland Clinic main campus, titled "Effect of 6% Hydroxyethyl Starch 130/0.4 on Kidney and Haemostatic Function in Cardiac Surgical Patients." Of 141 patients who were randomized to receive either 6% HES 130/0.4 or 5% human albumin for intraoperative plasma volume replacement, 135 patients were included in the data analysis (HES n = 66, albumin n = 69). We assessed the cardiopulmonary bypass-induced inflammatory response end points by comparing the 2 groups' serum concentrations of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and macrophage migration inhibitory factor (MIF), measured at baseline and at 1 and 24 hours after surgery. We also compared the 2 groups' postoperative pulmonary function end points, including the ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (Pao2:Fio2 ratio), dynamic lung compliance, oxygenation index (OI), and ventilation index (VI) at baseline, within 1 hour of arrival to the intensive care unit, and before tracheal extubation. The differences in the postoperative levels of inflammatory response and pulmonary function between the HES and albumin groups were assessed individually in linear mixed models.

RESULTS

Serum concentrations of the inflammatory markers (TNF-α, IL-6, MIF) were not significantly different (P ≥ .05) between patients who received 6% HES 130/0.4 or 5% albumin, and there was no significant heterogeneity of the estimated treatment effect over time (P ≥ .15). The results of pulmonary function parameters (Pao2:Fio2 ratio, dynamic compliance, OI, VI) were not significantly different (P ≥ .05) between groups, and there was no significant heterogeneity of the estimated treatment effect over time (P ≥ .15).

CONCLUSIONS

Our investigation found no significant difference in the concentrations of inflammatory markers and measures of pulmonary function between cardiac surgical patients who received 6% HES 130/0.4 versus 5% albumin.

The Preoperative Inflammatory Status Affects the Clinical Outcome in Cardiac Surgery

Aims: There are many reasons for the increase in post-operative mortality and morbidity in patients undergoing surgery. In fact, an activated inflammatory state before cardiac surgery, can potentially worsen the patient’s prognosis and the effects of this preoperative inflammatory state in the medium-term remains unknown. Methods: There were 470 consecutive patients who underwent cardiac surgery, and were divided in three groups according to the median values of preoperative C-reactive protein (CRP) and fibrinogen (FBG): The first group was the low inflammatory status group (LIS) with 161 patients (CRP < 0.39 mg/dL and FBG < 366 mg/dL); the second was the medium inflammatory status group (MIS) with 150 patients (CRP < 0.39 mg/dL and FBG ≥ 366 mg/dL or CRP ≥ 0.39 mg/dL and FBG < 366 mg/dL,); and the third was the high inflammatory status group (HIS) with 159 patients (CRP ≥ 0.39 mg/dL and FBG ≥ 366 mg/dL,). Results: The parameters to be considered for the patients before surgery were similar between the three groups except, however, for age, left ventricular ejection fraction (LVEF) and the presence of arterial hypertension. The operative mortality was not significantly different between the groups (LIS = 2.5%, MIS = 6%, HIS = 6.9%, p = 0.16) while mortality for sepsis was significantly different (LIS = 0%, MIS = 1.3%, HIS = 3.7%, p = 0.03). The infections were more frequent in the HIS group (p = 0.0002). The HIS group resulted in an independent risk factor for infections (relative risk (RR) = 3.1, confidence interval (CI) = 1.2–7.9, p = 0.02). During the 48-months follow-up, survival was lower for the HIS patients. This HIS group (RR = 2.39, CI = 1.03–5.53, p = 0.05) and LVEF (RR = 0.96, CI = 0.92–0.99, p = 0.04) resulted in independent risk factors for mortality during the follow-up. Conclusions: The patients undergoing cardiac surgery with a preoperative highly activated inflammatory status are at a higher risk of post-operative infections. Furthermore, during the intermediate follow-up, the preoperative highly activated inflammatory status and LVEF resulted in independent risk factors for mortality.

Circulating MIF Levels Predict Clinical Outcomes in Patients With ST-Elevation Myocardial Infarction After Percutaneous Coronary Intervention

BACKGROUND

The purpose of the study was to assess the value of admission macrophage migration inhibitory factor (MIF) levels in predicting clinical outcomes in ST-elevation myocardial infarction (STEMI) patients.

METHODS

For this study we recruited 498 STEMI patients after they received percutaneous coronary intervention (PCI), 40 with stable angina pectoris and 137 healthy participants. Plasma MIF levels were measured at admission and after PCI. The primary end points were in-hospital mortality and major adverse cardio-and/or cerebrovascular events (MACCE) during hospitalization and 3.2-year follow-up period.

RESULTS

Admission MIF levels were elevated in 88.4% of STEMI patients over the upper reference limit of healthy controls and it was 3- to 7-fold higher than that in stable angina pectoris and control groups (122 ± 61 vs 39 ± 19 vs 17 ± 8 ng/mL; P < 0.001). Admission MIF levels were significantly higher in patients who died after myocardial infarction vs survivors. For predicting in-hospital mortality using the optimal cutoff value (127.8 ng/mL) of MIF, the area under the receiver operating characteristic curve for MIF was 0.820, similar area under the receiver operating characteristic curve values for predicting short-term outcomes were observed for high-sensitivity troponin T, CK-MB, N-terminal probrain natriuretic peptide, and Global Registry of Acute Coronary Events (GRACE) score. Although peak high-sensitivity troponin T and N-terminal probrain natriuretic peptide also predicted MACCE during the follow-up period, only higher admission MIF levels predicted in-hospital mortality and MACCE during the 3.2-year follow-up. Multivariate regression analysis showed the independent predictive value of a higher admission MIF level (≥ 127.8 ng/mL) on in-hospital mortality (odds ratio, 9.1; 95% confidence interval, 1.7-47.2) and 3.2-year MACCE (hazard ratio, 2.8; 95% confidence interval, 1.5-5.6).

CONCLUSIONS

A higher admission MIF level is an independent predictor for in-hospital mortality and long-term MACCE in STEMI patients who underwent PCI.

Comparison of Two Miniaturized Cardiopulmonary Bypass Systems Regarding Inflammatory Response

Cardiopulmonary bypass (CPB) is a known mediator of systemic inflammatory response. Extracorporeal circulations are undergoing continuous modifications and optimizations to achieve better results. Hence we aim to compare the inflammatory response associated with two recent miniature extracorporeal circulation systems during normothermic CPB. We measured plasma levels of cytokines including interleukin (IL)-1β, IL-6, IL-10, tumor necrosis factor-α, migration inhibitory factor (MIF), receptor for advanced glycation endproduct, and cluster of differentiation 40 ligand in 60 consecutive patients during the first 24 h after CPB. The patients were prospectively randomized to one of three trial groups: patients in group A were operated with the minimal extracorporeal circulation circuit (MECC, Maquet, Rastatt, Germany), group B operated with the extracorporeal circulation circuit optimized (ECC.O, Sorin, Italy), and group C operated with a conventional extracorporeal circuit (CECC, Maquet). Arterial blood samples were collected at intervals before, 30 min after initiation, and after termination of CPB. Further samples were collected 6 and 24 h after CPB. IL-10 levels were significantly raised in the CECC group as compared with either of the mini ECC-circuits with a peak concentration at 6 h postoperatively. Human MIF concentrations were significantly higher in the CECC group starting 30 min after CPB and peaking at the end of CPB. The overall reduction in cytokine concentrations in the mini-ECC groups correlated with a lower need for blood transfusion in MECC and a shorter mechanical ventilation time for ECC.O. Normothermic CPB using minimally invasive extracorporeal circulation circuits can reduce the inflammatory response as measured by cytokine levels, which may be beneficial for perioperative preservation of pulmonary function and hemostasis in low risk patients.

Mass Spectrometric Immunoassay for the qualitative and quantitative analysis of the cytokine Macrophage Migration Inhibitory Factor (MIF)

Background

The cytokine MIF (Macrophage Migration Inhibitory Factor) has diverse physiological roles and is present at elevated concentrations in numerous disease states. However, its molecular heterogeneity has not been previously investigated in biological samples. Mass Spectrometric Immunoassay (MSIA) may help elucidate MIF post-translational modifications existing in vivo and provide additional clarity regarding its relationship to diverse pathologies.

Results

In this work, we have developed and validated a fully quantitative MSIA assay for MIF, and used it in the discovery and quantification of different proteoforms of MIF in serum samples, including cysteinylated and glycated MIF. The MSIA assay had a linear range of 1.56-50 ng/mL, and exhibited good precision, linearity, and recovery characteristics. The new assay was applied to a small cohort of human serum samples, and benchmarked against an MIF ELISA assay.

Conclusions

The quantitative MIF MSIA assay provides a sensitive, precise and high throughput method to delineate and quantify MIF proteoforms in biological samples.

Role of MIF in myocardial ischaemia and infarction: insight from recent clinical and experimental findings

First discovered in 1966 as an inflammatory cytokine, MIF (macrophage migration inhibitory factor) has been extensively studied for its pivotal role in a variety of inflammatory diseases, including rheumatoid arthritis and atherosclerosis. Although initial studies over a decade ago reported increases in circulating MIF levels following acute MI (myocardial infarction), the dynamic changes in MIF and its pathophysiological significance following MI have been unknown until recently. In the present review, we summarize recent experimental and clinical studies examining the diverse functions of MIF across the spectrum of acute MI from brief ischaemia to post-infarct healing. Following an acute ischaemic insult, MIF is rapidly released from jeopardized cardiomyocytes, followed by a persistent MIF production and release from activated immune cells, resulting in a sustained increase in circulating levels of MIF. Recent studies have documented two distinct actions of MIF following acute MI. In the supra-acute phase of ischaemia, MIF mediates cardioprotection via several distinct mechanisms, including metabolic activation, apoptosis suppression and antioxidative stress. In prolonged myocardial ischaemia, however, MIF promotes inflammatory responses with largely detrimental effects on cardiac function and remodelling. The pro-inflammatory properties of MIF are complex and involve MIF derived from cardiac and immune cells contributing sequentially to the innate immune response evoked by MI. Emerging evidence on the role of MIF in myocardial ischaemia and infarction highlights a significant potential for the clinical use of MIF agonists or antagonists and as a unique cardiac biomarker.

High postoperative blood levels of macrophage migration inhibitory factor are associated with less organ dysfunction in patients after cardiac surgery

Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine that exerts protective effects during myocardial ischemia/reperfusion injury. We hypothesized that elevated MIF levels in the early postoperative time course might be inversely associated with postoperative organ dysfunction as assessed by the simplified acute physiology score (SAPS) II and sequential organ failure assessment (SOFA) score in patients after cardiac surgery. A total of 52 cardiac surgical patients (mean age [± SD] 67 ± 10 years; EuroScore: 7) were enrolled in this monocenter, prospective observational study. Serum levels of MIF and clinical data were obtained after induction of anesthesia, at admission to the intensive care unit (ICU), 4 h after admission and at the first and second postoperative day. To characterize the magnitude of MIF release, we compared blood levels of samples from cardiac surgical patients with those obtained from healthy volunteers. We assessed patient outcomes using the SAPS II at postoperative d 1 and SOFA score for the first 3 d of the eventual ICU stay. Compared to healthy volunteers, patients had already exhibited elevated MIF levels prior to surgery (64 ± 50 versus 13 ± 17 ng/mL; p < 0.05). At admission to the ICU, MIF levels reached peak values (107 ± 95 ng/mL; p < 0.01 versus baseline) that decreased throughout the observation period and had already reached preoperative values 4 h later. Postoperative MIF values were inversely correlated with SAPS II and SOFA scores during the early postoperative stay. Moreover, MIF values on postoperative d 1 were related to the calculated cardiac power index (r = 0.420, p < 0.05). Elevated postoperative MIF levels are inversely correlated with organ dysfunction in patients after cardiac surgery.

Washing red blood cells and platelets transfused in cardiac surgery reduces postoperative inflammation and number of transfusions: results of a prospective, randomized, controlled clinical trial

OBJECTIVES

Children undergoing cardiac surgery with cardiopulmonary bypass are susceptible to additional inflammatory and immunogenic insults from blood transfusions. We hypothesize that washing red blood cells and platelets transfused to these patients will reduce postoperative transfusion-related immune modulation and inflammation.

DESIGN

Prospective, randomized, controlled clinical trial.

SETTING

University hospital pediatric cardiac intensive care unit.

PATIENTS

Children from birth to 17 yrs undergoing cardiac surgery with cardiopulmonary bypass.

INTERVENTIONS

Children were randomized to an unwashed or washed red blood cells and platelet transfusion protocol for their surgery and postoperative care. All blood was leuko-reduced, irradiated, and ABO identical. Plasma was obtained for laboratory analysis preoperatively, immediately, and 6 and 12 hrs after cardiopulmonary bypass. Primary outcome was the 12-hr postcardiopulmonary bypass interleukin-6-to-interleukin-10 ratio. Secondary measures were interleukin levels, C-reactive protein, and clinical outcomes.

MEASUREMENTS AND MAIN RESULTS

One hundred sixty-two subjects were studied, 81 per group. Thirty-four subjects (17 per group) did not receive any blood transfusions. Storage duration of blood products was similar between groups. Among transfused subjects, the 12-hr interleukin ratio was significantly lower in the washed group (3.8 vs. 4.8; p = .04) secondary to lower interleukin-6 levels (after cardiopulmonary bypass: 65 vs.100 pg/mL, p = .06; 6 hrs: 89 vs.152 pg/mL, p = .02; 12 hrs: 84 vs.122 pg/mL, p = .09). Postoperative C-reactive protein was lower in subjects receiving washed blood (38 vs. 43 mg/L; p = .03). There was a numerical, but not statistically significant, decrease in total blood product transfusions (203 vs. 260) and mortality (2 vs. 6 deaths) in the washed group compared to the unwashed group.

CONCLUSIONS

Washed blood transfusions in cardiac surgery reduced inflammatory biomarkers, number of transfusions, donor exposures, and were associated with a nonsignificant trend toward reduced mortality. A larger study powered to test for clinical outcomes is needed to determine whether these laboratory findings are clinically significant.

Prophylactic corticosteroids for cardiopulmonary bypass in adults

BACKGROUND

High-dose prophylactic corticosteroids are often administered during cardiac surgery. Their use, however, remains controversial, as no trials are available that have been sufficiently powered to draw conclusions on their effect on major clinical outcomes.

OBJECTIVES

The objective of this meta-analysis was to estimate the effect of prophylactic corticosteroids in cardiac surgery on mortality, cardiac and pulmonary complications.

SEARCH STRATEGY

Major medical databases (CENTRAL, MEDLINE, EMBASE, CINAHL and Web of Science) were systematically searched for randomised studies assessing the effect of corticosteroids in adult cardiac surgery. Database were searched for the full period covered, up to December 2009. No language restrictions were applied.

SELECTION CRITERIA

Randomised controlled trials comparing corticosteroid treatment to either placebo treatment or no treatment in adult cardiac surgery were selected. There were no restrictions with respect to length of the follow-up period. All selected studies qualified for pooling of results for one or more end-points.

DATA COLLECTION AND ANALYSIS

The processes of searching and selection for inclusion eligibility were performed independently by two authors. Also, quality assessment and data-extraction of selected studies were independently performed by two authors. The primary endpoints were mortality, cardiac and pulmonary complications. The main effect measure was the Peto odds ratio comparing corticosteroids to no treatment/placebo.

MAIN RESULTS

Fifty-four randomised studies, mostly of limited quality, were included. Altogether, 3615 patients were included in these studies. The pooled odds ratio for mortality was 1.12 (95% CI 0.65 to 1.92), showing no mortality reduction in patients treated with corticosteroids. The odds ratios for myocardial and pulmonary complications were 0.95, (95% CI 0.57 to 1.60) and 0.83 (95% CI 0.49 to 1.40), respectively. The use of a random effects model did not substantially influence study results. Analyses of secondary endpoints showed a reduction of atrial fibrillation and an increase in gastrointestinal bleeding in the corticosteroids group.

AUTHORS' CONCLUSIONS

This meta-analysis showed no beneficial effect of corticosteroid use on mortality, cardiac and pulmonary complications in cardiac surgery patients.

Macrophage migration inhibitory factor (MIF): a promising biomarker

Macrophage migration inhibitory factor (MIF) is an immunoregulatory cytokine, the effect of which on arresting random immune cell movement was recognized several decades ago. Despite its historic name, MIF also has a direct chemokine-like function and promotes cell recruitment. Multiple clinical studies have indicated the utility of MIF as a biomarker for different diseases that have an inflammatory component; these include systemic infections and sepsis, autoimmune diseases, cancer, and metabolic disorders such as type 2 diabetes and obesity. The identification of functional promoter polymorphisms in the MIF gene (MIF) and their association with the susceptibility or severity of different diseases has not only served to validate MIF's role in disease development but also opened the possibility of using MIF genotype information to better predict risk and outcome. In this article, we review the clinical data of MIF and discuss its potential as a biomarker for different disease applications.

Central venous saturation: a prognostic tool in cardiac surgery patients

BACKGROUND

Central venous oxygen saturation (ScvO(2)) is a valuable prognostic marker in sepsis. However, its value in cardiac surgery has not been assessed yet. This study aimed at evaluating ScvO(2) as a tool for predicting short-term organ dysfunction (OD) after cardiac surgery.

METHODS

A prospective cohort including cardiac surgery patients submitted to a goal-oriented therapy to maintain ScvO(2) above 70% was studied. Postoperative blood samples collected at 30 minutes (T1), 6 hours (T2), and 24 hours (T3) for ScvO(2) measurement were selected to further analysis. Two groups were formed according to the absence (G0) or presence (G1) of OD defined as a Sequential Organ Failure Assessment (SOFA) score >or=5 on the third postoperative day. A logistic regression analysis was performed to identify the variables independently associated with OD on the third postoperative day.

RESULTS

From the 246 patients included, 54 (22%) developed OD and were defined as G1. The mortality rates in G0 and G1 were 1.6% and 31.5%, respectively (P < .001). In the comparative analysis between G0 and G1, the ScvO(2) values were remarkably lower in G1 at T1 (66.2 +/- 9.2 vs 62.3 +/- 11.6; P = .009), T2 (69.6 +/- 5.9 vs 63.5 +/- 9.4; P <or= .001), and T3 (69.6 +/- 5.6 vs 64.6 +/- 6.4; P <or= .001). The variables independently associated with OD in the final logistic regression model were Cleveland score (95% CI: 1.13-1.44; OR: 1.27; P < .001), lactate at T3 (95% CI:1.21-3.15; OR 1.95; P = .006), BE at T3 (95% CI:0.69-0.93; OR 0.80; P = .005); ScvO(2) at T2 (95% CI:0.86-0.96; OR 0.91; P = .002), and ScvO(2) at T3 (95% CI:0.83-0.95; OR 0.89; P = .002).

CONCLUSION

Postoperative ScvO(2) can be a valuable tool to predict OD after major cardiac surgeries. Its kinetics should be carefully followed in that setting.

Macrophage migration inhibitory factor in pediatric patients undergoing surgery for congenital heart repair

Macrophage migration inhibitory factor (MIF), a proinflammatory mediator, has been shown to be elevated following heart surgery in adults and may be associated with several postoperative complications, including cardiac and pulmonary dysfunction. In this study, we aimed to measure perioperative plasma MIF, interleukin (IL)-8, and free T4 in 20 children age <4 years undergoing surgical repair of congenital heart lesions with left ventricular volume overload, and to determine whether the response of these mediators determined postoperative outcomes. Plasma samples were obtained preoperatively, immediately on arrival in the pediatric intensive care unit (PICU), and at 12, 24, and 48 h. Patients were continuously monitored in the PICU, and data were recorded daily for therapeutic and monitoring procedures that reflected the invasiveness, intensity, and complexity of care rendered (therapeutic interventional scoring system, TISS). Preoperative plasma MIF, IL-8, and free T4 were not different from age-matched healthy children. However, plasma MIF and IL-8 increased significantly 2 h after completion of cardiopulmonary bypass, and then normalized within 24 h. Peak postoperative levels of MIF (48 +/- 24 ng/mL) and IL-8 (79 +/- 57 pg/mL) correlated significantly with duration of cardiopulmonary bypass. The magnitude of the postoperative increase in plasma MIF was associated with increased number of days required for mechanical ventilation (r = 0.553; P = 0.012), and peak plasma IL-8 correlated significantly with the fraction of inhaled oxygen (FiO(2)) required immediately after surgery (r = 0.510; P = 0.02). Higher circulating MIF levels correlated significantly with increased inotropic support requirements on the second postoperative day, whereas higher postoperative IL-8 levels were associated with higher TISS scores, suggesting increased need for postoperative medical care. These data suggest a potential negative effect of high circulating levels of MIF in the immediate postoperative period on respiratory and cardiovascular functions, and support the development of therapeutic strategies targeting MIF function in this clinical setting.

Macrophage migration inhibitory factor induces cardiomyocyte apoptosis

Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine that causes cardiac contractile dysfunction, whereas inactivation of MIF improves cardiac function in experimental animal models of sepsis. We used cultured cardiomyocytes to determine whether MIF-induced contractile dysfunction was mediated in part by myocyte apoptosis and to identify MIF-activated intracellular signaling pathways in this process. MIF treatment significantly increased myocyte apoptosis in a dose-dependent manner to 15.5+/-3.9% and 26.0+/-7.1% TUNEL positive nuclei (20 and 30 ng/ml MIF for 24h) vs control (3.7+/-0.9%). This effect was attenuated by inactivation of MIF with the chemical inhibitor, ISO-1. MIF-induced cleavage of caspase 3 and reduction of Bcl-xL/Bax were similarly attenuated by ISO-1 pre-treatment. MIF stimulated the rapid, transient phosphorylation of stress kinases, p38MAPK and JNK. Thus, MIF induces cardiomyocyte apoptosis by activating stress kinases and mitochondria-associated apoptotic mechanisms, whereas inactivation of MIF pro-inflammatory activity improves cardiomyocyte survival.

Circulating inflammatory mediators and organ dysfunction after cardiovascular surgery with cardiopulmonary bypass: a prospective observational study

Introduction

Cardiovascular surgery with cardiopulmonary bypass (CPB) has improved in past decades, but inflammatory activation in this setting is still unpredictable and is associated with several postoperative complications. Perioperative levels of macrophage migration inhibitory factor (MIF) and other inflammatory mediators could be implicated in adverse outcomes in cardiac surgery.

Methods

Serum levels of MIF, monocyte chemoattractant protein (MCP)-1, soluble CD40 ligand, IL-6 and IL-10 from 93 patients subjected to CPB were measured by enzyme-linked immunosorbent assay and compared with specific and global postoperative organ dysfunctions through multiple organ dysfunction score (MODS) and sequential organ failure assessment (SOFA).

Results

Most of the cytokines measured had a peak of production between 3 and 6 hours after CPB, but maximum levels of MIF occurred earlier, at the cessation of CPB. Among specific organ dysfunctions, the most frequent was hematological, occurring in 82% of the patients. Circulatory impairment was observed in 73.1% of the patients, and 51% of these needed inotropics or vasopressors within the first 24 hours after surgery. The third most frequent dysfunction was pulmonary, occurring in 48.4% of the patients. Preoperative levels of MIF showed a relevant direct correlation with the intensity of global organ dysfunction measured by SOFA (ρ = 0.46, p < 0.001) and MODS (ρ = 0.50, p < 0.001) on the third day after surgery. MCP-1 production was associated with postoperative thrombocytopenia, and MIF was related to the use of a high dose of vasopressors in patients with cardiovascular impairment and also to lower values of the ratio of partial arterial oxygen tension (PaO₂) to fraction of inspired oxygen (FiO₂) registered in the first 24 hours after CPB.

Conclusion

Despite the multifactorial nature of specific or multiple organ dysfunctions, MIF should be explored as a predicting factor of organ dysfunction, or even as a potential therapeutic target in decreasing postoperative complications.

EFFECTS OF DEXAMETHASONE ON MACROPHAGE MIGRATION INHIBITORY FACTOR PRODUCTION IN SEPSIS

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that plays a major role in the pathogenesis of sepsis. Some studies have indicated that glucocorticoids increase MIF production in physiological conditions. The goal of this study was to determine whether glucocorticoid treatment also upregulates MIF production in sepsis. Male NMRI mice (6-10 weeks old) underwent laparotomy, proximal ligation of the cecum, and double perforation with a 19-gauge needle (cecal ligation and puncture). Mice were randomly treated with saline (control) or dexamethasone at doses of 0.1, 1, or 10 mg/kg ip. At 6 or 18 h postoperatively, 10 mice per group were euthanized; and blood, peritoneal fluid, liver, lung, kidney, and heart tissue samples were retrieved. MIF, IL-6, TNF-alpha, and IL-10 were measured by enzyme-linked immunosorbent assay. Sepsis induced by cecal ligation and puncture produced a marked increase in MIF and cytokine levels in plasma and peritoneal fluid. Treatment with dexamethasone 10 mg/kg decreased MIF levels in plasma after 18 h, but there was no effect of dexamethasone on MIF production locally in the peritoneal cavity or in the liver, lungs, heart, or kidneys. We conclude that glucocorticoid treatment does not upregulate MIF production in sepsis.

Cytokine response in children undergoing surgery for congenital heart disease

Pediatric cardiac surgery with cardiopulmonary bypass (CPB) induces a complex inflammatory response that may cause multiorgan dysfunction. The objective of this study was to measure postoperative cytokine production and correlate the magnitude of this response with intraoperative variables and postoperative outcomes. Serum samples from 20 children (median age, 15 months) undergoing cardiac surgery with CPB were obtained preoperatively and on postoperative days (POD) 1-3. Serum levels of interleukin (IL)-6, IL-8, and IL-10 increased significantly on POD 1 (p < 0.01) vs pre-op values to 271 +/- 68, 44 +/- 9, 7.5 +/- 0.8 pg/ml, respectively, whereas serum IL-1beta, IL-12, and tumor neurosis factor -alpha were not significantly changed. The serum IL-6 and IL-8 levels correlated positively (p < 0.01) with the degree of postoperative medical intervention as measured by the Therapeutic Interventional Scoring System and indicated a greater need for inotropic support (p = 0.057). A negative correlation (p < 0.01) between IL-6, IL-8, and mixed venous oxygen saturation suggested compromised cardiopulmonary function. Patients with single ventricle anatomy had the highest levels of IL-6 and IL-8 (629 +/- 131 and 70 +/- 17 pg/ml, respectively), with a mean CPB time of 106 +/- 23 minutes. Thus, the proinflammatory response after surgery with CPB was associated with postoperative morbidity with increased need for medical intervention.

Higher Levels of Serum Cytokines and Myocardial Tissue Markers During On-Pump Versus Off-Pump Coronary Artery Bypass Surgery

Increased Troponin I levels and pro-inflammatory cytokines have been reported in most patients undergoing cardiac surgery, ascribed to the type and extent of surgery, reperfusion injury, and the method of myocardial protection. We investigated their levels in patients undergoing on-pump (CCAB) or off-pump (OPCAB) coronary artery bypass surgery and whether these correlated with the extent of myocardial injury. One hundred twenty patients were prospectively randomized to undergo OPCAB (n = 60) or CCAB (n = 60). Hemodynamic and respiratory data, as well as serum CK-MB mass fraction, Troponin I, and interleukin (IL)-6, IL-8, and IL-10 levels, were collected perioperatively. Demographic, hemodynamic, and respiratory parameters were similar between the two groups. Troponin I was significantly lower in the OPCAB than in the CCAB group, either at the end of ischemia, end of surgery, 6-hour and 24-hour postoperatively (4 +/- 3, 5 +/- 3, 7 +/- 5, and 8 +/- 3 microg/L, vs. 19 +/- 18, 27 +/- 19, 28 +/- 13.5, and 33 +/- 8.5 microg/L, respectively, p < 0.05). Serum cytokine levels in the OPCAB patients were lower compared to the CCAB group at the end of surgery (32 +/- 35, 25 +/- 30, and 40 +/- 30 pg/ml for IL-6, IL-8, and IL-10 vs. 230 +/- 30, 140 +/- 70, and 125 +/- 50 pg/ml, respectively, p < 0.05). Plasma IL-6 levels correlated with the Troponin I levels at the end of surgery in both groups (r = 0.45, p = 0.01). Thus, OPCAB surgery is associated with reduced levels of Troponin I and activation of cytokines, compared to those in the CCAB group. High levels of these factors could correlate with myocardial damage during coronary artery bypass surgery. This finding warrants further laboratory and clinical confirmation in the future.

Endocrine markers of severity and prognosis in critical illness

The cellular processes that unfold in critical illness involve a variety of circulating substances, that may provide clinically relevant insight into the severity and outcome. Among hormonal markers, cortisol, several thyroid-related substances, as well as natriuretic peptides are discussed in this review. Glucose and lipids constitute metabolic markers, the identification and treatment of the former has been of particular importance. Among immune markers, both proinflammatory and anti-inflammatory cytokines, such as interleukin-6, contribute essential prognostic information. Finally, the complement and coagulation pathways also provide unique insight into this complex and heterogeneous process.

Macrophage migration inhibitory factor is associated with positive cultures in patients with sepsis after cardiac surgery

This prospective consecutive observational study describes the blood levels of macrophage migration inhibitory factor (MIF), other cytokines, and markers of acute-phase response in 49 consecutive patients who developed the clinical syndrome of sepsis after cardiac surgery. Before starting antimicrobial treatment, all patients underwent microbiologic screening, and blood samples were collected. These samples subsequently were assayed for MIF, macrophage chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6 and -10, procalcitonin (PCT), and C-reactive protein (CRP). Patients with positive cultures (n = 25) had a higher mortality (P = 0.046) and higher levels of MIF (P < 0.001) than those with negative cultures (n = 24). We could not detect significant difference between the groups concerning the levels of CRP, PCT, IL6, IL10, MCP-1, or TNF-alpha. MIF levels showed an area under receiver operator curve of 0.823 for the prediction of culture-proven bacterial infection, with the best cut-off value at 988.5 pg/mL. In conclusion, circulating levels of MIF could be indicated as a valuable marker of microbiologically documented sepsis in patients after cardiac surgery, which suggests that MIF may be prospectively explored as a useful diagnostic tool in this setting.

Beyond sepsis pathophysiology with cytokines: what is their value as biomarkers for disease severity?

Sepsis is a major challenge in medicine. It is a common and frequently fatal infectious condition. The incidence continues to increase, with unacceptably high mortality rates, despite the use of specific antibiotics, aggressive operative intervention, nutritional support, and anti-inflammatory therapies. Typically, septic patients exhibit a high degree of heterogeneity due to variables such as age, weight, gender, the presence of secondary disease, the state of the immune system, and the severity of the infection. We are at urgent need for biomarkers and reliable measurements that can be applied to risk stratification of septic patients and that would easily identify those patients at the highest risk of a poor outcome. Such markers would be of fundamental importance to decision making for early intervention therapy or for the design of septic clinical trials. In the present work, we will review current biomarkers for sepsis severity and especially the use of cytokines as biomarkers with important pathophysiological role.

Coronary artery bypass surgery and longitudinal evaluation of the autonomic cardiovascular function

INTRODUCTION

Imbalance in autonomic cardiovascular function increases the risk for sudden death in patients with coronary artery disease (CAD), but the time course of the impact of coronary artery bypass grafting (CABG) on autonomic function has been little studied. Thus, the purpose of the present study was to determine the effects of the CABG on the cardiovascular autonomic function.

METHODS

Patients undergoing CABG (n = 13) and two matched control groups (patients with CAD who refused surgical treatment [n = 9], and healthy volunteers [n = 9]) underwent a prospective longitudinal study consisting of autonomic evaluation before and after (3, 6, 15, 30, 60, and 90 days) surgery, including measurement of heart rate variability (HRV), respiratory sinus arrhythmia (RSA), and Valsalva maneuver.

RESULTS

After CABG there was a decrease in, and a later recovery of, (1) the HRV in the time domain and in the frequency domain, (2) RSA, and (3) Valsalva maneuver.

CONCLUSIONS

CABG caused an impairment, reversible after 60 days, of cardiovascular autonomic function, with a maximal decrease on about the sixth day after surgery.