Inflammatory cytokines and soluble receptors after coronary artery bypass grafting

Effects of high-intensity inspiratory muscle training on systemic inflammatory response in cardiac surgery - A randomized clinical trial

PURPOSE

Preoperative inspiratory muscle training reduces the incidence of postoperative pulmonary complications after cardiac surgery, but training protocols vary widely in terms of intensity. Currently, the mechanisms underlying the effectiveness of this practice are not known. The purpose of the present study is to determine whether preoperative high-intensity inspiratory muscle training (HI-IMT) modulates the perioperative systemic inflammatory response in cardiac surgery patients.

METHODS

Participants awaiting surgical aortic valve replacement were randomized to 3 to 6 weeks preoperative home-based HI-IMT or same duration low-intensity inspiratory muscle training (LI-IMT). The primary outcome was the preoperative value of the soluble tumor necrosis factor receptor 1 (sTNFR1). Secondary outcomes assessed perioperative evolution of the cytokines: sTNFR1, Tumor necrosis factor-α, Interleukin (IL)-6, IL-8, IL10, IL1β, and their combined z-score; reflecting post-training and postoperative inflammatory response. Perioperative pulmonary function and postoperative clinical outcomes were collected.

RESULTS

Between February 2018 and March 30, 2019 patients were randomized, to HI-IMT or LI-IMT. There were no differences between the groups in terms of baseline characteristics. The median (IQR) training duration was 34 (28-44) days. After training, the median (IQR) predicted maximal inspiratory pressure was higher in the HI-IMT vs LI-IMT group (119 (96-142%) vs 97 (81-107%); p = .04) Levels of the sTNFR1 cytokine increased during training in the HI-IMT group, pre vs post training (Median (IQR) 1073 (920; 1219) vs 1172 (965; 1368) ng/L; p = .03). The 24-h postoperative global inflammatory score was lower in the HI-IMT than in the LI-IMT group (Median (IQR), -0.37 (-0.62, 0.03) vs -0.10 (-0.17, 0.49), p = .04). Global inflammatory scores were not different at other time points. There were no significant differences between the groups in post-operative pulmonary function and postoperative clinical outcome.

CONCLUSION

High intensity inspiratory muscle training shows immunomodulatory properties. These properties could explain why preoperative inspiratory muscle training can lead to lung protection after cardiac surgery.

Characteristics of Interleukin-6 Signaling in Elective Cardiac Surgery—A Prospective Cohort Study

Interleukin-6 (IL-6) can cause pro- and anti-inflammatory effects via different signaling pathways. This prospective study investigated the perioperative kinetics of IL-6, soluble IL-6 receptor (sIL-6R), and soluble glycoprotein 130 (sgp130) in elective patients undergoing cardiopulmonary bypass (CPB). IL-6, sIL-6R, and sgp130 were measured simultaneously and consecutively at 19 timepoints until the 10th postoperative day (POD). The proportion of pro- and anti-inflammatory pathways were determined by calculating sIL-6R/IL-6 and sIL-6R/sgp130 ratios. We analyzed 93 patients. IL-6 increased during surgery with reaching a plateau two hours after CPB and peaking on POD 1 (188.5 pg mL⁻¹ (IQR, 126.6; 309.2)). sIL-6R decreased at the beginning of the surgical procedure, reaching a nadir level on POD 2 (26,311 pg mL⁻¹ (IQR, 22,222; 33,606)). sgp130 dropped immediately after CPB initiation (0.13 ng mL⁻¹ (IQR, 0.12; 0.15)), followed by a continuous recovery until POD10. The sIL-6R/IL-6 ratio decreased substantially at the beginning of the procedure, reaching a nadir on POD 1 (149.7 (IQR, 82.4; 237.4)), while the sIL-6R/sgp130 ratio increased simultaneously until 6 h post CPB (0.219 (IQR 0.18; 0.27)). In conclusion, IL-6 exhibited high inter-individual variability reflecting an inhomogeneous inflammatory response. Pro-inflammatory effects and overwhelming inflammation were rare and predominantly anti-inflammatory effects were found.

In vivo immune signatures of healthy human pregnancy: Inherently inflammatory or anti-inflammatory?

Changes in maternal innate immunity during healthy human pregnancy are not well understood. Whether basal immune status in vivo is largely unaffected by pregnancy, is constitutively biased towards an inflammatory phenotype (transiently enhancing host defense) or exhibits anti-inflammatory bias (reducing potential responsiveness to the fetus) is unclear. Here, in a longitudinal study of healthy women who gave birth to healthy infants following uncomplicated pregnancies within the Canadian Healthy Infant Longitudinal Development (CHILD) cohort, we test the hypothesis that a progressively altered bias in resting innate immune status develops. Women were examined during pregnancy and again, one and/or three years postpartum. Most pro-inflammatory cytokine expression, including CCL2, CXCL10, IL-18 and TNFα, was reduced in vivo during pregnancy (20-57%, p<0.0001). Anti-inflammatory biomarkers (sTNF-RI, sTNF-RII, and IL-1Ra) were elevated by ~50-100% (p<0.0001). Systemic IL-10 levels were unaltered during vs. post-pregnancy. Kinetic studies demonstrate that while decreased pro-inflammatory biomarker expression (CCL2, CXCL10, IL-18, and TNFα) was constant, anti-inflammatory expression increased progressively with increasing gestational age (p<0.0001). We conclude that healthy resting maternal immune status is characterized by an increasingly pronounced bias towards a systemic anti-inflammatory innate phenotype during the last two trimesters of pregnancy. This is resolved by one year postpartum in the absence of repeat pregnancy. The findings provide enhanced understanding of immunological changes that occur in vivo during healthy human pregnancy.

Attenuated recovery of contractile function in aging hearts following global ischemia/reperfusion: Role of extracellular HSP27 and TLR4

BACKGROUND

While cardiac functional recovery is attenuated in the elderly following cardiac surgery with obligatory global myocardial ischemia/reperfusion (I/R), the underlying mechanism remains incompletely understood. We observed previously that human and mouse myocardium releases heat shock protein (HSP) 27 during global I/R. Extracellular HSP27 induces myocardial inflammatory response and plays a role in post-ischemic cardiac dysfunction in adult mouse hearts.

OBJECTIVE

This study was to determine the role of extracellular HSP27 and Toll-like receptor 4 (TLR4) in the attenuated functional recovery in aging mouse hearts following global I/R.

METHODS AND RESULTS

Hearts isolated from aging (18-24 months) and adult (4-6 months) mice were subjected to ex vivo global I/R. Augmented release of HSP27 in aging hearts is associated with greater production of cytokines (TNF-α and IL-1β) and worse functional recovery. Anti-HSP27 suppressed the inflammatory response and markedly improved functional recovery in aging hearts. Perfusion of recombinant HSP27 to aging hearts resulted in greater cytokine production and more severe contractile depression in comparison to adult hearts. TLR4 deficiency abolished cytokine production and functional injury in aging hearts exposed to recombinant HSP27. Interestingly, aging hearts had higher TLR4 protein levels and displayed enhanced TLR4-mediated NF-κB activation following HSP27 stimulation or I/R.

CONCLUSION

Extracellular HSP27 and TLR4 jointly enhance the inflammatory response and hamper functional recovery following I/R in aging hearts. The enhanced inflammatory response to global I/R and attenuated post-ischemic functional recovery in aging hearts is due, at least in part, to augmented myocardial release of HSP27 and elevated myocardial TLR4 levels.

Interleukin 6 production during cardiac surgery correlates with increasing age

BACKGROUND

Cardiac surgery produces a proinflammatory response characterized by cytokine production. Proinflammatory cytokines such as interleukin 6 (IL-6) may contribute to morbidity and mortality after cardiopulmonary bypass (CPB). Elderly patients undergoing CPB are at increased risk of morbidity and mortality. We hypothesized that patients aged >70 y produce more IL-6 during CPB.

METHODS

Twenty-three patients (ages 23-80) undergoing cardiac surgery had blood sampled from the ascending aorta and coronary sinus on initial cannulation for bypass, at 30 min of aortic cross-clamp time, on release of the aortic cross-clamp, and at 20 min after reperfusion. Group 1 patients (n = 8) were aged <60 y, group 2 patients (n = 7) were aged between 60 and 70 y, and group 3 patients (n = 8) were aged >70 y. Plasma levels of tumor necrosis factor-alpha, IL-1, and IL-6 were analyzed.

RESULTS

The three groups did not differ with respect to preoperative ejection fraction, New York Heart Association classification, mean aortic cross-clamp time, or mean CPB time. IL-6 levels rose throughout myocardial ischemia and reperfusion in all three age groups. The increase in IL-6 during ischemia and reperfusion in the age group >70 was greater than the increase in younger patients. IL-6 was similar in the coronary sinus and the ascending aorta.

CONCLUSIONS

These data suggest that patients aged >70 y undergoing cardiac operations generate more IL-6 during CPB. The increased circulating IL-6 in elderly patients may incite a proinflammatory state that could subsequently underlie the associated higher mortality and morbidity of these procedures in elderly patients.

Lung inflammatory response syndrome after cardiac-operations and treatment of lornoxicam

The majority of patients survive after extracorporeal circulation without any clinically apparent deleterious effects. However, disturbances exist in various degrees sometimes, which indicate the harmful effects of cardiopulmonary bypass (CPB) in the body. Several factors during extracorporeal circulation either mechanical dependent (exposure of blood to non-biological area) or mechanical independent (surgical wounds, ischemia and reperfusion, alteration in body temperature, release of endotoxins) have been shown to trigger the inflammatory reaction of the body. The complement activation, the release of cytokines, the leukocyte activation and accumulation as well as the production of several "mediators" such as oxygen free radicals, metabolites of arachidonic acid, platelet activating factors (PAF), nitric acid, and endothelin. The investigation continues today on the three metabolites of lornoxicam (the hydroxylated metabolite and two other metabolites of unknown chemical composition) to search for potential new pharmacological properties and activities.

Recent advances in perioperative medicine: highlights from the literature for the cardiothoracic and vascular anesthesiologist

There have been major advances in perioperative cardiothoracic and vascular medicine. Because of promising data, steroids, statins, and endothelin antagonists are being clinically tested in randomized trials with adult cardiac surgical patients. In vascular surgical patients, recent meta-analysis has revealed that interventions such as beta-blockade or endovascular stenting for peripheral vascular lesions may not improve outcome overall. Furthermore, a landmark trial has shown that anesthetic technique does not affect outcome after carotid endarterectomy. The surgical Apgar score may become part of routine clinical care of the vascular surgical patient because it predicts outcome and can be calculated at the bedside. Recent studies confirm that the serious perioperative risks of hyperglycemia also apply to nondiabetic and pediatric cardiac surgical patients. This has been highlighted in the new guidelines from the Society of Thoracic Surgeons. Perioperative myocardial protection is possible with ischemic preconditioning and omega-3 fatty acids. Pneumonia after lung resection may be reduced significantly by broadening antibiotic prophylaxis. Transfusion-related acute lung injury has immediate and delayed presentations that highlight the dangers of blood transfusion. Perioperative renal dysfunction after adult cardiac surgery is significantly reduced by the infusion of sodium bicarbonate. Although promising, further trials are required. Taken together, these recent advances will have significant influence on the future practice of cardiovascular and thoracic anesthesia as the ongoing search for perioperative outcome improvement achieves results.

Endothelin-A receptor inhibition after cardiopulmonary bypass: cytokines and receptor activation

BACKGROUND

Basic studies have suggested that cross-talk exists between the endothelin-A receptor (ET-AR) and tumor necrosis factor signaling pathway. This study tested the hypothesis that administration of an ET-AR antagonist at the separation from cardiopulmonary bypass would alter the tumor necrosis factor activation in the early postoperative period.

METHODS

Patients (n = 44) were randomly allocated to receive bolus infusion of vehicle, 0.1, 0.5, 1, or 2 mg/kg of the ET-AR antagonist (sitaxsentan), at the separation from cardiopulmonary bypass (n = 9, 9, 9, 9, and 8, respectively). Plasma levels of tumor necrosis factor-alpha and soluble tumor necrosis factor receptor 1 and 2 were measured.

RESULTS

Compared with the vehicle group at 24 hours, plasma levels of tumor necrosis factor-alpha and tumor necrosis factor receptor 2 (indicative of receptor activation) were reduced in the 1 mg/kg ET-AR antagonist group (by approximately 13 pg/mL and approximately 0.5 ng/mL, respectively; p < 0.05). Plasma tumor necrosis factor receptor I levels also decreased (by approximately 1 ng/mL) after infusion of the higher doses of the ET-AR antagonist and remained lower (by approximately 3 ng/mL) at 24 hours after infusion (p < 0.05). In addition, a dose effect was observed between the ET-AR antagonist and these indices of tumor necrosis factor activation (p < 0.01).

CONCLUSIONS

This study demonstrated a mechanistic relationship between the ET-AR and tumor necrosis factor receptor activation in the post-cardiac surgery period. Thus, in addition to the potential cardiovascular effects, a selective ET-AR antagonist can modify other biological processes relevant to the post-cardiac surgery setting.

Preoperative plasma levels of soluble tumor necrosis factor receptor type I (sTNF-RI) predicts adverse events in cardiac surgery

OBJECTIVE

The objective was to estimate the sTNF-RI preoperative measure in the identification of patients with bad outcome and death.

METHODS

We assessed prospectively sixty-two patients submitted electively to myocardial revascularization with ECC or heart valve surgery. The sTNF-RI levels were determined by the Sandwich-Type ELISA method before anesthetic induction. Clinical, surgical characteristics and sTNF-RI levels were compared among patients with good (group I, n=46) or bad outcome (group II, n=16--length of stay in the ICU for over 72 h or death).

RESULTS

No difference was found between the verified mortality (6.4%) and the predicted by EuroSCORE (3.0%), p=0.48. The sTNF-RI levels were higher in group II (1322) than group I (748) p=0.009 (levels >954, 69% sensitivity and 70% specificity for good outcome, 44% positive predicted value and 85% negative). The sTNF-RI levels were higher in patients who died (1556) versus (759) p=0.029, (levels >1230, 79% sensitivity, 75% specificity, 20% positive predicted value and 98% negative). In the multivariate logistic regression model sTNF-RI (OR=1.002, IC95% 1.000-1.005, p=0.014) and age (OR=1.083, IC95% 1.010-1.161, p=0.025) were independently related to the risk of bad outcome.

CONCLUSIONS

Basal levels of sTNF-RI yield prognostic information in patients who undergo heart surgery.

Cell Salvage Alters the Systemic Inflammatory Response After Off-Pump Coronary Artery Bypass Grafting Surgery

BACKGROUND

Retransfused cardiotomy suction blood contains elevated inflammatory markers and is a bypass independent source of inflammatory mediators. We hypothesized that, during off-pump coronary artery bypass (OPCAB) grafting surgery, avoiding retransfusion of unwashed cardiotomy suction blood would beneficially alter both urinary and plasma cytokine concentrations and be renoprotective.

METHODS

Thirty-seven OPCAB surgery patients were randomly allocated to control (retransfusion of unwashed shed blood) and treatment (retransfusion of washed shed blood or discarding of unwashed blood) groups. Over 72 hours we measured plasma (tumor necrosis factor-alpha [TNF-alpha], interleukin-8, interleukin-6, interleukin-10, TNF soluble receptor-2, and interleukin-1 receptor antagonist) and urinary TNF soluble receptor-2 and interleukin-1 receptor antagonist and markers of renal injury and dysfunction (N-acetyl beta D glucosaminidase and alpha1-microglobulin).

RESULTS

We demonstrated elevated proinflammatory cytokines in cardiotomy suction blood, which were effectively eliminated by cell salvage. After retransfusion, in comparison with controls, the treatment group had reduced plasma TNF soluble receptor-2. As compared with controls, treatment group patients also demonstrated significantly reduced levels of the urinary anti-inflammatory cytokine TNF soluble receptor-2. There were no between group differences in markers of renal injury or dysfunction.

CONCLUSIONS

We have demonstrated that the management of shed mediastinal blood alters perioperative, systemic, plasma and urinary cytokine homeostasis at OPCAB surgery but does not impact on subclinical renal injury or dysfunction in this low risk group of patients.

Tumor necrosis factor-alpha and interleukin-10 gene expression in peripheral blood mononuclear cells after cardiac surgery

OBJECTIVE

Cytokine response after cardiac surgery may be genetically influenced. A study was carried out to investigate the relation between cytokine gene expression in peripheral blood mononuclear cells, genotype, and clinical events after cardiac surgery.

DESIGN

A case-control study was performed.

SETTING

Cardiac intensive care unit in a university hospital.

SUBJECTS

A total of 82 patients having elective cardiac surgery were divided into those having uncomplicated recovery (n = 48) or recovery complicated by hyperlactatemia or requirement for inotropic support (n = 34).

INTERVENTIONS

The relative change in peripheral blood mononuclear cell tumor necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10) messenger RNA 1 and 6 hrs after cardiopulmonary bypass was compared with a baseline preoperative level using quantitative reverse transcriptase polymerase chain reaction. DNA was analyzed for carriage of TNF-alpha and IL-10 polymorphic alleles.

MEASUREMENTS AND MAIN RESULTS

Cardiopulmonary bypass was longer in duration in the complicated group. TNF-alpha gene expression decreased and IL-10 gene expression increased in peripheral blood mononuclear cells after surgery when compared with preoperative levels. One hour after cardiopulmonary bypass, the complicated group had more TNF-alpha and less IL-10 messenger RNA production than the uncomplicated group. The IL-10/TNF-alpha ratio was greater in uncomplicated than in complicated recovery patients. An IL-10 haplotype was identified that was less frequent in the complicated group. There was no difference between groups in TNF-alpha genotype. On multivariate analysis, cardiopulmonary bypass time and the IL-10/TNF-alpha messenger RNA ratio were independent predictors of outcome.

CONCLUSIONS

There is a predominant anti-inflammatory cytokine response after uneventful cardiac surgery. IL-10 may have a protective role after cardiac surgery.

Inflammatory cytokines in pediatric cardiac surgery and variable effect of the hemofiltration process

Cardiac surgery with cardiopulmonary bypass (CPB) elicits an inflammatory response and has a multitude of biological consequences, ranging from subclinical organ dysfunction to severe multiorgan failure. Pediatric patients are more prone to have a reaction that can jeopardize their outcome. Cytokines are supposed to be important mediators in this response: limiting their circulating levels is, therefore, appealing. We investigated the pattern of cytokine release during pediatric operation for congenital heart anomalies in 20 patients, and the effect of hemofiltration. Tumor necrosis factor alpha (TNF-alpha) was elevated after anesthesia induction and showed significant decrease during CPB. Hemofiltration reduced its concentration, but the effect disappeared on the following day. Interleukin-1 (IL-1) increased slowly at the end of CPB and hemofiltration had no effect. Interleukin-6 (IL-6) showed a tendency toward augmentation during rewarming and hemofiltration did not significantly affect the course. Soluble interleukin-6 receptor (sIL-6r) had a pattern similar to TNF-alpha, but hemofiltration had no effect. On the other hand, interleukin-8 (IL-8) behaved like IL-6. Our findings suggest that baseline clinical status, anesthetic drugs, and maneuvers before incision may elicit a cytokine response, whereas rewarming is a critical phase of CPB. Hemofiltration is effective in removal of TNF-alpha, but its role is debatable for the control of IL-1, IL-6, sIL-6r and IL-8 levels.

Intensive insulin therapy does not alter the inflammatory response in patients undergoing coronary artery bypass grafting: a randomized controlled trial [ISRCTN95608630]

INTRODUCTION

Strict control of plasma glucose in diabetic and non-diabetic patients has been shown to improve outcome in several clinical settings. There is extensive evidence that glucose can stimulate the production of pro-inflammatory cytokines such as tumor necrosis factor (TNF)-alpha and IL-6, with no effect on the anti-inflammatory cytokine IL-10. We hypothesized that strict glucose regulation results in a change in cytokine balance from a pro-inflammatory state to a more balanced anti-inflammatory condition. In a randomized controlled trial we studied the effect of strict glycemic control on the local and systemic pro-inflammatory and anti-inflammatory balance in non-diabetic patients undergoing elective coronary artery bypass grafting with cardiopulmonary bypass.

METHODS

After surgery patients were randomly assigned to intensive insulin therapy (blood glucose between 80 and 110 mg/dl) or conventional insulin therapy (blood glucose less than 200 mg/dl). At 0, 1, 2, 4, 8, 12, 16 and 24 hours after admission to the intensive care unit, plasma samples and samples from the mediastinal drains were obtained. We measured the concentrations of the pro-inflammatory cytokines TNF-alpha and IL-6 and the anti-inflammatory cytokine IL-10 by enzyme-linked immunosorbent assay.

RESULTS

Both patient groups were comparable in demographics, clinical characteristics and peri-operative data. In the intensive treatment group, glucose levels were significantly lower than in the conventionally treated group. No differences were found between both groups in the concentrations of TNF-alpha, IL-6 and IL-10 in plasma samples or in fluid draining the mediastinal cavity. Levels of IL-6 and IL-10 were significantly higher in mediastinal fluid samples than in plasma samples, suggesting a compartmentalized production of cytokines.

CONCLUSION

The protective effect of intensive insulin therapy in patients after cardiac surgery with cardiopulmonary bypass is not related to a change in cytokine balance from a pro-inflammatory to an anti-inflammatory pattern. Systemic cytokine levels are not representative of the local inflammatory response.

Cortisol antiinflammatory effects are maximal at postoperative plasma concentrations*

OBJECTIVE

To determine the plasma concentration of cortisol that is needed for maximal suppression of the systemic inflammatory response to cardiac surgery with cardiopulmonary bypass.

DESIGN

Prospective, randomized, double-blind clinical study of cardiac surgical patients.

SETTING

Operating room and inpatient care facility of a university medical center.

SUBJECTS

Sixty elective cardiac surgical patients scheduled for coronary artery bypass graft, cardiac valve replacement, or both.

INTERVENTIONS

Patients were randomized to receive one of three different hydrocortisone doses, by intravenous infusion, for 6 hrs before, during, and immediately after surgery while also receiving etomidate to suppress endogenous cortisol production.

MEASUREMENTS AND MAIN RESULTS

Serial determinations of plasma interleukin-6 were studied as a marker of systemic inflammation. Measurements of interleukin-10 were used as a marker of the compensatory antiinflammatory response. Plasma cortisol concentrations in an untreated control group rose from 17 microg/dL before surgery to a mean of 43 microg/dL by 4 hrs after surgery. A dose of hydrocortisone (4 microg/kg/min for 6 hrs) that maintained plasma cortisol between 40 and 50 microg/dL, starting 60-90 mins before surgery, significantly suppressed plasma interleukin-6 after surgery compared with control while significantly increasing plasma interleukin-10 during surgery. Plasma interleukin-6 after surgery was not suppressed further by increasing the dose of hydrocortisone to 8 microg/kg/min, although the mean peak plasma interleukin-10 concentration increased further compared with the group that received the 4 microg/kg/min hydrocortisone dose.

CONCLUSIONS

At the doses studied, cortisol-induced suppression of plasma interleukin-6 during and after cardiac surgery appears to be a saturable phenomenon at the concentration of plasma cortisol that is normally achieved after surgery in untreated patients.

Soluble adhesion molecules in coronary artery bypass surgery

Plasma levels of sE-selectin, sP-selectin, and sICAM-1 were measured before anesthesia and at 0.5, 4, and 20 hours after cardiopulmonary bypass in 37 men undergoing coronary artery bypass surgery. Plasma sE-selectin remained close to the preoperative levels. The levels of sP-selectin increased significantly from 46.5 +/- 15.3 ng x mL(-1) to 69.3 +/- 39.6 ng x mL(-1) at 0.5 hours, 84.1 +/- 45.5 ng x mL(-1) at 4 hours, and 79.6 +/- 35.5 ng x mL(-1) at 20 hours. Plasma sICAM-1 levels decreased 0.5 hours after cardiopulmonary bypass, recovered at 4 hours, and showed a significant increase at 20 hours. The changes in plasma levels of adhesion molecules did not correlate with the duration of bypass or aortic crossclamping, hemodynamics, or creatine kinase-MB levels. However, sE-selectin and sICAM-1 levels increased considerably more in patients who needed norepinephrine in the intensive care unit. These results indicate that the transient changes in plasma levels of soluble adhesion molecules are not associated with postoperative myocardial injury in low-risk coronary grafting, although they correlate with the need for a vasopressor.

Imbalance of pro- and anti-inflammatory cytokine responses in elderly patients after coronary artery bypass grafting

BACKGROUND AND AIMS

Increased inflammatory activity has been observed in elderly people. The aim of this study was to determine whether cytokine responses after coronary artery bypass grafting (CABG) in elderly patients are different from those in younger patients.

METHODS

Fifty-five male patients admitted for first-time elective coronary artery bypass surgery were divided into two age groups: group I, patients younger than 70 years (N=40); and group II, patients aged 70 years or older (N=15). Perioperative levels of cytokines and CK-MB were measured. Hemodynamic data were recorded.

RESULTS

Marginally higher IL-6 (p=0.048) and IL-8 (p=0.041) levels were observed during the intensive care unit (ICU) stay in the elderly as compared with younger patients. Lower IL-10 levels were detected in the elderly 5 minutes after reperfusion to the myocardium (p<0.05). Although the postoperative hemodynamic change was similar in both groups, the elderly needed vasopressor treatment more often during the ICU stay. This was associated with lower IL-10 levels 5 minutes after reperfusion.

CONCLUSIONS

The present results show the age-related imbalance of pro- and anti-inflammatory responses after CABG, associated with hemodynamic instability in the elderly.

Stress induced IL-10 does not seem to be essential for early monocyte deactivation following cardiac surgery

An increase in circulating levels of IL-10 is believed to contribute to immunosuppression caused by major surgery. Cortisol and catecholamines have been shown to be important costimulatory factors for IL-10 secretion in humans. As thoracic epidural block (TEB) should blunt the perioperative increases in cortisol and catecholamines we investigated whether IL-10 secretion is influenced by TEB. Twenty-six patients undergoing coronary artery bypass graft surgery using cardiopulmonary bypass were randomized to receive either general anesthesia (GA) or GA plus TEB. Sensory and pain levels were measured to demonstrate clinical effectiveness. Plasma concentrations of epinephrine, norepinephrine, cortisol, IL-6 and IL-10 as well as monocyte surface expression of HLA-DR and their ex vivo capacity to release TNF-alpha after LPS stimulation were measured perioperatively. TEB was clinically effective and patients receiving TEB showed decreased circulating levels of IL-10. However, this decrease was independent of decreased levels of cortisol or epinephrine. No influence of TEB on IL-6 levels, monocyte capacity to ex vivo release TNF-alpha upon LPS stimulation or their expression of HLA-DR was found. In conclusion, high TEB reduces antiinflammatory immune suppressing mediators including IL-10 and stress mediators. At least in cardiac surgery patients the monocyte functional depression is not related to systemic release of IL-10 and the influence of cortisol or epinephrine is less important for early monocyte deactivation than what in vitro and animal models have suggested.

Effect of tumor necrosis factor-alpha on endothelial and inducible nitric oxide synthase messenger ribonucleic acid expression and nitric oxide synthesis in ischemic and nonischemic isolated rat heart

OBJECTIVES

The present study aimed to investigate the influence of endogenous tumor necrosis factor-alpha (TNF-alpha) that was synthesized during ischemia and exogenous TNF-alpha on endothelial and inducible nitric oxide synthase (eNOS and iNOS) messenger ribonucleic acid (mRNA) expression and nitric oxide (NO) production in the isolated rat heart.

BACKGROUND

Tumor necrosis factor-alpha is recognized as being a proinflammatory cytokine with a significant cardiodepressant effect. One of the proposed mechanisms for TNF-alpha-induced cardiac contractile dysfunction is increased NO production via iNOS mRNA upregulation, but the role of NO in TNF-alpha-induced myocardial dysfunction is highly controversial.

METHODS

Isolated rat hearts studied by a modified Langendorff model were randomly divided into subgroups to investigate the effect of 1-h global cardioplegic ischemia or the effect of 1-h perfusion with exogenous TNF-alpha on the expression of eNOS mRNA and iNOS mRNA and on NO production.

RESULTS

After 1 h of ischemia, there were significant increases in TNF levels in the effluent (from hearts), and eNOS mRNA expression had declined (from 0.91 +/- 0.08 to 0.68 +/- 0.19, p < 0.001); but there were no changes in iNOS mRNA expression, and NO was below detectable levels. Perfusion of isolated hearts with TNF-alpha had a cardiodepressant effect and decreased eNOS mRNA expression to 0.67 +/- 0.04 (p < 0.002). Inducible nitric oxide synthase mRNA was unchanged, and NO was below detectable levels.

CONCLUSIONS

We believe this is the first study to directly show that TNF-alpha does not increase NO synthesis and release but does downregulate eNOS mRNA in the ischemic and nonischemic isolated rat heart.

Increase in plasma and surface CD163 levels in patients undergoing coronary artery bypass graft surgery

Although haptoglobin polymorphism has been shown to be a genetic risk factor in coronary artery disease, its mechanisms of action are incompletely defined. Recently, a macrophage scavenger receptor for the uptake of haptoglobin-hemoglobin (Hp-Hb) complexes was cloned and designated CD163. Macrophage expression of CD163 is increased by glucocorticoids, IL-10 and IL-6. To better understand the in vivo response of CD163 to an inflammatory stimulus and glucocorticoid treatment, we studied 18 patients who underwent elective coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB). We report a rapid increase in plasma levels of soluble CD163 by 1 h post-declamping the aorta during CABG surgery with CPB. Furthermore, we demonstrate significant increases in monocyte CD163 on post-operative day 1; 14-fold for patients pre-treated with methylprednisolone and 3-fold for those who did not receive exogenous glucocorticoids. These findings show CD163 to be rapidly mobilized in response to systemic inflammatory stimuli and to be affected significantly by glucocorticoids in vivo. The proposed role of CD163 as a Hp-Hb scavenger and anti-inflammatory molecule, in conjunction with the results of this study, make CD163 an intriguing target for potential manipulation of the acute response to inflammation.