Perioperative and postoperative course of cytokines and the metabolic activity of neutrophils in human cardiac operations and heart transplantation

Cytokines and MicroRNA in Coronary Artery Disease

Cardiovascular disease (CVD) is a major health problem globally. The high incidence and case fatality of CVD are, to a large extent, a consequence of its late diagnosis and lack of highly sensitive and specific markers. Only a very small number of biomarkers, such as troponin, detect late disease. There is some evidence of an association and dysregulation between specific cytokines in the pathogenesis of CVD. These molecules are involved in inflammatory and immune mechanisms associated with atherogenesis. Several molecular/cellular pathways that include STAT, MAPK, and SMAD are modulated by cytokines. Against this background, microRNAs (miRNAs) are a class of noncoding RNAs with important roles in pathological events, leading to atherosclerotic CVD. It has been shown that the latter could affect cytokine production and contribute to progression of atherosclerotic CVD. Moreover, modulation of miRNAs appears to inhibit cardiomyocyte apoptosis, attenuate infarct size, and reduce cardiac dysfunction. This review highlights several recent preclinical and clinical studies on the role of cytokines in CVD, novel miRNA-based therapeutic approaches for therapeutic intervention, and potential circulating cytokines that have promise as biomarkers in CVD.

The role of inflammation in atrial fibrillation following open heart surgery

This study investigated the role of systemic inflammation in the development of atrial fibrillation (AF) after coronary artery bypass grafting (CABG). CABG was performed using cardiopulmonary bypass in 77 patients. Pre-operative AF was present in six patients (7.8%) and postoperative AF developed in 13 (18.3%) of the 71 patients with pre-operative sinus rhythm. Post-operative mediastinal drainage was significantly increased in patients with post-operative AF compared with those with sinus rhythm. Plasma E-selectin, P-selectin and vascular cell adhesion molecule levels were not significantly different between patients with pre- and post-operative sinus rhythm, those with pre-operative sinus rhythm and post-operative AF, and those with pre- and post-operative AF. There were significant differences between pre- and post-operative C-reactive protein, interleukin (IL)-6 and IL-10 levels within all three groups, but no differences in these parameters between the groups. Thus, in all groups there were significant alterations in mediators indicative of systemic inflammation following CABG, but comparisons between the groups revealed no differences predictive of AF.

Differential White Cell Count Relationships With Human Cardiac Allograft Rejection

The focus of research in allograft rejection has targeted the lymphocyte, with little attention given to the neutrophil. Recent data indicate that a perioperative neutrophil influx into the cardiac allograft influences early rejection. Factors that influence neutrophil transendothelial migration might offer predictive markers of rejection. We explored the relationship between the number of circulating neutrophils in heart transplant recipients and the development of rejection. Differential white cell counts were obtained prior to transplantation and concurrently with subsequent endomyocardial rejection surveillance biopsies for 53 heart transplant recipients undergoing 410 biopsies. Preoperative differential white cell counts had no relationship with rejection. In the first 3 months after transplantation, no relationship was found between contemporary differential white cell counts and rejection. However, more than 3 months following surgery, rejection grade positively correlated on univariate analysis with neutrophil counts and the usage of cyclosporine, prednisolone, and mycophenolate. There was no relationship with eosinophils or lymphocytes. Multivariate analysis demonstrated a persistent relationship among rejection severity, neutrophil count, and prednisolone usage. A significant positive association of higher steroid usage with higher rejection grades must reflect efforts to treat patients with rejection. The significant association of higher neutrophil counts with higher rejection severity might suggest a pathological contribution to rejection. However, given the neutrophilia response to acute steroid administration, we must conclude that the neutrophil association was related to steroid administration. The absence of a relationship between white cell counts and rejection suggests that functional rather than antiproliferative strategies may offer the greatest therapeutic potential.

Effects of atorvastatin on systemic inflammatory response after coronary bypass surgery

OBJECTIVES

Systemic inflammatory response occurs frequently after coronary artery bypass surgery, and it is strongly correlated with the risk of postoperative morbidity and mortality. Recent studies demonstrate that treatment with statin is associated with a significant and marked decrease in inflammation-associated variables such as the C-reactive protein, cytokines, and adhesion molecules. Therefore, we investigated the effects of preoperative atorvastatin treatment on systemic inflammatory response and perioperative morbidity after cardiopulmonary bypass.

DESIGN

Double-blinded, placebo-controlled, randomized study.

SETTING

University hospital.

PATIENTS

Forty patients were randomized to treatment with atorvastatin (20 mg/day, group A, n=20) or placebo (group B, n=20) 3 wks before surgery.

INTERVENTIONS

Three-week treatment by atorvastatin 20 mg/day.

MEASUREMENT AND MAIN RESULTS

Postoperative serum levels of both interleukin-6 and interleukin-8 increased significantly over baseline, but the peak levels observed 4 hrs postoperatively were significantly lower in the atorvastatin group. In the same fashion, CD11b expression on neutrophils was significantly lower in the statin group at 4 and 24 hrs postoperatively. Finally, neutrophil-endothelial adhesion was significantly reduced in the statin patients compared with controls. The operation time, blood loss, need for inotropic support, intubation time, and length of intensive care unit or hospital stay did not differ significantly between the two groups. The systemic inflammatory response syndrome score on postoperative days 1 and 2 was comparable in both groups.

CONCLUSIONS

Pretreatment with atorvastatin significantly reduces cytokine release and neutrophil adhesion to the venous endothelium in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass.

The effect of (1-->3)-beta-D-glucans, carboxymethylglucan and schizophyllan on human leukocytes in vitro

(1-->3)-beta-D-glucans are known as potent inductors of humoral and cell-mediated immunity in humans and animals. (1-->3)-beta-D-glucans isolated from various sources differ in their chemical structure and physical parameters and consequently in their immunomodulatory potential. In this study the immunomodulatory activity of two (1-->3)-beta-D-glucans schizophyllan (SPG) and carboxymethylglucan (CMG) was determined and compared on human blood leukocytes in vitro. Both SPG and CMG activated blood phagocytes and lymphocytes as demonstrated by increased whole blood production of reactive oxygen species, by increased production of pro-inflammatory cytokines IL-6, IL-8, and TNF-alpha, by increased surface expression of CD69 on lymphocytes, and by altered expression of CD11b and CD62L on polymorphonuclear leukocytes and monocytes. SPG demonstrated a significantly higher potential to stimulate blood phagocytes and production of selected pro-inflammatory cytokines than CMG. The higher potency of SPG to stimulate human blood phagocytes in vitro could be caused by factors such as higher branching frequencies or neutral polymer charge of SPG or different conformation in solution if compared with CMG.

Quantitative cytokine gene expression in human tonsils at excision and during histoculture assessed by standardized and calibrated real-time PCR and novel data processing

Real-time reverse transcription polymerase chain reaction (RT-PCR) assays were developed for the quantification of expression of the genes for human interleukin (IL)-1beta, IL-2, IL-6, IL-8, IL-10, IL-12, IL-15, interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta and for the endogenous reference hydroxymethylbilane synthase (HMBS). The assays detected as little as five plasmid copies and were 100% specific. The creation and integration of a calibration sample into the assays permitted their calibration across experiments. To handle the high number of generated data, the correlator of advanced real-time assays (CARTA) software was designed to organize samples and to automatically control and analyze TaqMan real-time RT-PCR data. The RT-PCR assays were applied to quantify levels of cytokine gene expression in human palatine tonsils at excision and during 4 days of histoculture. Similar longitudinal patterns of cytokine gene expression were observed in all donors, but the variations in spontaneous expression levels between donors were large. The expression levels in histocultures were constant over time and similar to the expression levels at excision except for IL-6 and IL-8, which markedly increased following the first 24 h of culture, possibly due to the initial stress. The standardized and calibrated RT-PCR assays quantify gene expression of human cytokines proved sensitive and specific for the investigation of cell behavior at the molecular level and the newly established CARTA software, a reliable tool for rapid data handling. Tonsil histocultures could serve as a valuable ex vivo model system for further, donor-dependent, studies on activation or repression of cytokine gene expression.