Enhanced proinflammatory response of mononuclear cells to in vitro LPS-challenge in patients with ventricular fibrillation in the setting of acute myocardial infarction

The complex crosstalk between inflammatory cytokines and ventricular arrhythmias

The network of cytokines consists one of the most extensively studied signaling systems of human body. Cytokines appear to modulate pathogenesis and progress of many different diseases in the human body, particularly in regards to cardiovascular system. However, their effects on the electrical system of the heart has been neglected. Over the past decade, attemps to understand this relationship led to the uncovering of the direct and indirect effects of cytokines on action potential propagation and cell depolarization. This relationship has been depicted in clinical practice as serum levels of cytokines are increasingly associated with prevalence of ventricular arrhythmias either isolated or secondary to either a heart condition or a systemic auto-immune disease. Thus, they present an appealing potential as a biomarker for prediction of arrhythmia generation, as well as the ourtcome of electrophysiological interventions.

Longitudinal assessments of erythropoietin-stimulating agent responsiveness and the association with specific clinical outcomes in dialysis patients

BACKGROUND

Dose requirements of erythropoietin-stimulating agents (ESAs) can vary considerably over time and may be associated with cardiovascular outcomes. We aimed to longitudinally assess ESA responsiveness over time and to investigate its association with specific clinical end points in a time-dependent approach.

METHODS

The German Diabetes and Dialysis study (4D study) included 1,255 diabetic dialysis patients, of whom 1,161 were receiving ESA treatment. In those patients, the erythropoietin resistance index (ERI) was assessed every 6 months during a median follow-up of 4 years. The association between the ERI and cardiovascular end points was analyzed by time-dependent Cox regression analyses with repeated ERI measures.

RESULTS

Patients had a mean age of 66 ± 8.2 years; 53% were male. During follow-up, a total of 495 patients died, of whom 136 died of sudden death and 102 of infectious death. The adjusted and time-dependent risk for sudden death was increased by 19% per 5-unit increase in the ERI (hazard ratio, HR = 1.19, 95% confidence interval, CI = 1.07-1.33). Similarly, mortality increased by 25% (HR = 1.25, 95% CI = 1.18-1.32) and infectious death increased by 27% (HR = 1.27, 95% CI = 1.13-1.42). Further analysis revealed that lower 25-hydroxyvitamin D levels were associated with lower ESA responsiveness (p = 0.046).

CONCLUSIONS

In diabetic dialysis patients, we observed that time-varying erythropoietin resistance is associated with sudden death, infectious complications and all-cause mortality. Low 25-hydroxyvitamin D levels may contribute to a lower ESA responsiveness.

Secreted frizzled-related protein-1 improves postinfarction scar formation through a modulation of inflammatory response

OBJECTIVE

The inflammatory response after myocardial infarction plays a crucial role in the healing process. Lately, there is accumulating evidence that the Wnt/Frizzled pathway may play a distinct role in inflammation. We have shown that secreted frizzled-related protein-1 (sFRP-1) overexpression reduced postinfarction scar size, and we noticed a decrease in neutrophil infiltration in the ischemic tissue. We aimed to further elucidate the role of sFRP-1 in the postischemic inflammatory process.

METHODS AND RESULTS

We found that in vitro, sFRP-1 was able to block leukocyte activation and cytokine production. We transplanted bone marrow cells (BMCs) from transgenic mice overexpressing sFRP-1 into wild-type recipient mice and compared myocardial healing with that of mice transplanted with wild-type BMCs. These results were compared with those obtained in transgenic mice overexpressing sFRP-1 specifically in endothelial cells or in cardiomyocytes to better understand the spatiotemporal mechanism of the sFRP-1 effect. Our findings indicate that when overexpressed in the BMCs, but not in endothelial cells or cardiomyocytes, sFRP-1 was able to reduce neutrophil infiltration after ischemia, by switching the balance of pro- and antiinflammatory cytokine expression, leading to a reduction in scar formation and better cardiac hemodynamic parameters.

CONCLUSION

sFRP-1 impaired the loop of cytokine amplification and decreased neutrophil activation and recruitment into the scar, without altering the neutrophil properties. These data support the notion that sFRP-1 may be a novel antiinflammatory factor protecting the heart from damage after myocardial infarction.

Naturally existing CD11c(low)CD45RB(high) dendritic cells protect mice from acute severe inflammatory response induced by thermal injury

Despite a good understanding of the process that initiates and promotes host inflammation induced by acute injury, little is known about the host immune cells responsible for the inhibition of inflammatory response to thermal injury. The aim of this study was to investigate the potential effect of naturally existing CD11c(low)CD45RB(high) dendritic cells (CD11c(low)CD45RB(high) DCs) on acute severe inflammatory response and mortality rate in burned mice. Changes in the percentage of distinct subsets of splenic DCs and production of cytokines (IL-6, TNF-α, CCL-2) as well as CC chemokine (CCL)-2 were measured by FACS at various time points. The influence of CD11c(low)CD45RB(high) DCs on IL-6, TNF-α, CCL-2 as well as IL-10 levels and mortality rate was observed following a single intraperitoneal injection of DCs to scald mice. Levels of IL-6, CCL-2 and TNF-α were peaked at postburn hours (PBHs) 12, and percentages of CD11c(low)CD45RB(high) DCs were elevated at PBH 12-24. A single intraperitoneal injection of CD11c(low)CD45RB(high) DCs to 15% total body surface area in scald mice led to significant decrease in IL-6, TNF-α and CCL-2, and lethality, but up-regulation of IL-10 compared with untreated mice from PBH 0 to 48. CD11c(low)CD45RB(high) DCs can effectively down-regulate the production of inflammatory cytokines and reduce the mortality rate in 15% TBSA scald injury mice.

Circadian variations of interleukin 6 in coronary circulations of patients with myocardial infarction

We hypothesize that higher morbidity of patients with ST-segment elevation myocardial infarction (STEMI) in the out-of-office hours differences in outcome after myocardial infarction may depend on the concentrations of inflammatory cytokines. The aim of the study was to determine the relation between the time of percutaneous coronary intervention (PCI) and local concentration of interleukin 6 (IL-6) and its soluble receptors (sIL-6R and sgp130) in patients with STEMI.

METHODS AND RESULTS

The study included 32 patients with invasively treated left anterior descending artery occlusion and no significant co-morbidities. Blood samples were drawn from coronary sinus and aorta before and after intervention. Patients admitted in the afternoon (13-20) presented significantly higher mean IL-6 levels in all samples than patients admitted in the morning. There was a positive correlation between time of intervention and concentrations of IL-6 in all samplings, but also with transcardiac IL-6 gradient at the end of procedure and IL-6 increase during PCI. We did not find any significant association between time of PCI and concentrations of sIL-6R and sgp130, time from pain to balloon, angiographic parameters or medical history.

CONCLUSIONS

Coronary concentration of IL-6 in patients with STEMI is significantly higher in the afternoon than in the morning. This might be involved in increased morbidity of those patients.

Clinical periodontal and microbiologic parameters in patients with acute myocardial infarction

BACKGROUND

The aim of this study was to evaluate the impact of clinical periodontal parameters and the presence of periodontal pathogens in patients with acute myocardial infarction (AMI).

METHODS

A total of 104 subjects (54 patients with AMI and 50 healthy controls) were included. Subgingival plaque samples were analyzed for periodontal pathogens Aggregatibacter actinomycetemcomitans (Aa; previously Actinobacillus actinomycetemcomitans), Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf; previously T. forsythensis), and Prevotella intermedia (Pi) using dot-blot hybridization.

RESULTS

Patients with AMI had a significantly higher frequency of probing depths (PDs) >or=4 mm than controls (39.2% versus 14.9%; P <0.0001). Among different cutoff levels, the frequency of >50% sites with PDs >or=4 mm showed the highest discrepancy between both groups (33% versus 0%; P <0.001). All periodontal pathogens were overrepresented in patients with AMI and positively correlated with increased periodontal PD and clinical attachment level (CAL). After adjustment for age, gender, smoking, body mass index, hypertension, plaque index, statin intake, and ratio of cholesterol to high-density lipoprotein, Pg remained a significant predictor for AMI (odds ratio [OR]: 13.6; 95% confidence interval [CI]: 3.1 to 59.8; P = 0.0005). Furthermore, the simultaneous presence of Aa + Pg (P = 0.0005) and Aa + Pg + Tf (P = 0.0018) were found with significantly higher frequency in patients with AMI than controls.

CONCLUSIONS

The results of our study confirm an association between periodontitis and AMI in which periodontal destruction was correlated with the presence of periodontal pathogens. In particular, Pg might be considered a potential risk indicator for AMI.

Clinical implications of cytokines in the critical-care unit

To understand the role of different cytokines in the pathophysiology and management of different acute cardiovascular disorders in critically ill patients, we reviewed most of the pertinent articles published on Medline, Scopus and EBSCO host research databases from 1985 to January 2009. We used the indexing terms 'cytokines', 'cardiovascular', 'sepsis', 'critical care', 'myocardial dysfunction', 'shock', 'thromboembolism', 'inflammatory' and 'arrhythmias'. Myocardial dysfunction, dysrhythmic and thromboembolic disorders all appear associated with important fluctuations in cytokines. When and how to sample cytokine levels and the ways in which cytokines contribute to patient deterioration or improvement require further clinical studies. The measurement and interplay of several different cytokines may ultimately be of substantial clinical importance in the diagnosis, treatment and prognosis of patients with different acute cardiovascular disorders managed by critical-care physicians in intensive-care units. Although the role of cytokines in cardiovascular disorders is debatable, the clinical implication of cytokines in the critical-care unit is a new horizon that warrants more attention.

Coronary sinus concentrations of interleukin 6 and its soluble receptors are affected by reperfusion and may portend complications in patients with myocardial infarction

Interleukin 6 (IL-6) is a pleiotropic cytokine involved in both inflammatory reaction and myocardial response to stress. Its effects largely depend on the concentration of the soluble receptors (sIL-6R and sgp130). We investigated the production of IL-6, sIL-6R and sgp130 by the heart during ischemia and reperfusion.

METHODS

The levels of IL-6 were determined in blood of 34 patients with first myocardial infarction (STEMI), left anterior descending (LAD) artery occlusion, otherwise normal coronaries, without significant co-morbidities and 16 comparable subjects with stable ischemic heart disease and lesion in LAD. Blood samples from coronary sinus (CS) and aorta (Ao) were drawn before percutaneous intervention (PCI), immediately after and at the end of the procedure. Venous blood from 30 healthy volunteers served as control.

RESULTS

STEMI patients presented high IL-6 concentrations that increased further after reperfusion when its levels in CS became significantly higher than in Ao. In both groups prior to the PCI there were significantly higher concentrations of sIL-6R in Ao than in CS. This difference disappeared immediately after reperfusion. STEMI patients who experienced cardiovascular complications had higher IL-6 concentration and higher transcardiac sIL-6R gradient than patients with event-free hospitalisation. This association was confirmed in multivariate logistic regression analysis. Myocardial infarction increases concentration of IL-6 that is further elevated by reperfusion. A transcardiac gradient of sIL-6R during ischemia may indicate that large amounts of soluble IL-6 receptors are bound to the infarcted heart and thus affect signal transduction. IL-6 and initial sIL-6R gradient may portend complications in STEMI patients.