Role of cytokines and adhesion molecules in ischemia and reperfusion in patients with acute myocardial infarction

The Relationship between the Use of Cold and Isothermic Blood Cardioplegia Solution for Myocardial Protection during Cardiopulmonary Bypass and the Ischemia-Reperfusion Injury

PURPOSE

In this study, we aimed to assess myocardial protection and ischemia-reperfusion injury in patients undergoing open heart surgery with isothermic blood cardioplegia (IBC) or hypothermic blood cardioplegia (HBC).

MATERIALS AND METHODS

A total of 48 patients who underwent isolated coronary artery bypass grafting or isolated mitral valve surgery between March 2017 and October 2017 were evaluated as randomized prospective study. Study groups (HBC: Group 1, IBC: Group 2) were compared in terms of interleukin 6 (IL-6), IL-8, IL-10, and complement factor 3a (C3a) levels, metabolic parameters, creatine kinase-muscle/brain (CK-MB) and high-sensitivity Troponin I (hsTn-I), and clinical outcomes.

RESULTS

Comparison of the markers of ischemia-reperfusion injury showed significantly higher levels of the proinflammatory cytokine IL-6 in the early postoperative period as well as IL-8, in Group 2 (p <0.001), whereas the anti-inflammatory cytokine IL-10 was significantly higher during the X1 time period (p = 0.11) in Group 2, and subsequently it was higher in Group 1. Using myocardial temperature probes, the target myocardial temperatures were measured in the patients undergoing open heart surgery with different routes of cardioplegia, and significant differences were noted (p = 0.000).

CONCLUSION

HBC for open heart surgery is associated with less myocardial injury and intraoperative and postoperative morbidity, indicating superior myocardial protection versus IBC.

Effect of Aspiration Thrombectomy on Microvascular Dysfunction in ST-Segment Elevation Myocardial Infarction With an Elevated Neutrophil Count

Background and Objectives

Aspiration thrombectomy (AT) during primary percutaneous coronary intervention (PCI) is an effective adjunctive therapy for ST-segment elevation myocardial infarction (STEMI). An elevated neutrophil count in STEMI is associated with microvascular dysfunction and adverse outcomes. We evaluated whether AT can improve microvascular dysfunction in patients with STEMI and an elevated neutrophil count.

Subjects and Methods

Seventy patients with STEMI undergoing primary PCI from August 2007 to February 2009 in our institution were classified by tertiles of neutrophil count on admission (<5,300/mm³, 5,300-7,600/mm³, and >7,600/mm³). The angiographic outcome was post-procedural thrombolysis in myocardial infarction (TIMI) flow grade. Microvascular dysfunction was assessed by TIMI myocardial perfusion (TMP) grade and ST-segment resolution on electrocardiography 90 minutes after PCI. The clinical outcome was major adverse cardiac event (MACE), defined as cardiac death, re-infarction, and target lesion revascularization at 9 months.

Results

There were no significant differences in the clinical characteristics and pre- and post-procedural TIMI flow grades between the neutrophil tertiles. As the neutrophil count increased, a lower tendency toward TMP grade 3 (83% vs. 52% vs. 54%, p=0.06) and more persistent residual ST-segment elevation (>4 mm: 13% vs. 26% vs. 58%, p=0.005) was observed. The 9-month MACE rate was similar between the groups. On subgroup analysis of AT patients (n=52) classified by neutrophil tertiles, the same tendency toward less frequent TMP grade 3 (77% vs. 56% vs. 47%, p=0.06) and persistent residual ST-segment elevation (>4 mm: 12% vs. 28% vs. 53%, p=0.05) was observed as neutrophil count increased.

Conclusion

A higher neutrophil count at presentation in STEMI is associated with more severe microvascular dysfunction after primary PCI, which is not improved with AT.

Relationship of admission neutrophil count to microvascular injury, left ventricular dilation, and long-term outcome in patients treated with primary angioplasty for acute myocardial infarction

BACKGROUND

The relationship of admission neutrophil count to the degree of microvascular injury, left ventricular (LV) volume, and long-term outcome after acute myocardial infarction (AMI) was examined in the present study.

METHODS AND RESULTS

The study group comprised 228 consecutive patients with a first anterior wall AMI who underwent primary angioplasty within 12 h of onset. The degree of microvascular injury was evaluated by Doppler guidewire. Adverse cardiac events were recorded during an average follow-up of 52+/-28 months. Using a receiver-operating characteristic analysis, a neutrophil count >or=7,260 cells/mm(3) was the best predictor of future cardiac events. By regression analysis, the neutrophil count significantly correlated with diastolic deceleration time (r=-0.40, p<0.0001), coronary flow reserve (r=-0.43, p<0.0001), and LV end-diastolic volume at 4 weeks (r=0.32, p<0.0001). Kaplan-Meier survival analysis showed a higher incidence of adverse cardiac events in patients with a high neutrophil count (p=0.002). By multivariate analysis, a neutrophil count >or=7,260 cells/mm(3) was an independent predictor of long-term adverse cardiac events (odds ratio 3.8, p=0.002).

CONCLUSION

Neutrophilia on admission is associated with impaired microvascular perfusion, LV dilation, and long-term adverse cardiac events in patients treated with primary angioplasty for AMI.

Relation between neutrophil counts on admission, microvascular injury, and left ventricular functional recovery in patients with an anterior wall first acute myocardial infarction treated with primary coronary angioplasty

Increased neutrophil counts have been associated with an increased risk of adverse clinical events after acute myocardial infarction (AMI). We examined the association of neutrophil counts on admission with degree of microvascular injury and left ventricular functional recovery after primary coronary angioplasty in AMI. We studied 116 patients with a first anterior wall AMI who underwent primary coronary angioplasty within 12 hours of onset. Patients were categorized into 3 groups based on initial neutrophil count: low (<5,000/mm(3)), intermediate (5,000 to 10,000/mm(3)), and high (>10,000/mm(3)). Coronary flow velocity parameters were assessed immediately after reperfusion using a Doppler guidewire. We defined severe microvascular injury as the presence of systolic flow reversal and a diastolic deceleration time <600 ms. Echocardiographic wall motion was analyzed before revascularization and 4 weeks after revascularization. In patients with a high neutrophil count, systolic flow reversal was more frequently observed, diastolic deceleration time was shorter, and coronary flow reserve was lower. By regression analysis, neutrophil count significantly correlated with diastolic deceleration time (r = -0.38, p <0.0001), coronary flow reserve (r = -0.33, p = 0.0004), and score for change in wall motion (r = -0.36, p = 0.0004). Multivariate analysis showed that neutrophil count on admission was an independent predictor of severe microvascular injury (odds ratio 2.94, p = 0.02). In conclusion, neutrophilia on admission is associated with impaired microvascular reperfusion and poor functional recovery after primary coronary angioplasty.

Value of 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) gated SPECT for the detection of silent myocardial ischemia in hemodialysis patients: clinical variables associated with abnormal test results

BACKGROUND

Although coronary artery disease is a major cause of mortality and morbidity in patients undergoing hemodialysis, there is no accurate diagnostic strategy for these patients.

AIM

To assess the value of 99mTc-methoxyisobutylisonitrile (99mTc-MIBI) gated single-photon emission computed tomography for the detection of silent myocardial ischemia in patients undergoing hemodialysis and to evaluate the clinical variables associated with abnormal test results.

METHODS

Thirty-one asymptomatic patients undergoing hemodialysis (20 men, 11 women), with a mean age of 45 years (range, 25-75 years), were included in the study. Serum electrolytes, creatinine, homocysteine and adhesion molecules were measured prior to dialysis. Ambulatory blood pressure, carotid intima-media thickness measurements, echocardiography and stress 99mTc-MIBI imaging were performed in all patients, whereas coronary angiography was performed only in patients with abnormal myocardial perfusion scintigraphy and/or echocardiography.

RESULTS

Gated myocardial perfusion scintigraphy results were abnormal in nine patients (29%) and coronary angiography was abnormal in six patients. After a median follow-up of 20 months (range, 14-28 months), nine patients experienced a cardiac event. Seven of the nine patients (78%) with abnormal myocardial perfusion scintigraphy suffered a cardiac event, compared with only two of 22 patients (9%) with normal myocardial perfusion scintigraphy (P<0.0001). Patients with abnormal perfusion scintigraphy had higher serum C-reactive protein, homocysteine and adhesion molecule levels and the duration of hemodialysis was significantly longer.

CONCLUSION

In asymptomatic hemodialysis patients, gated myocardial perfusion scintigraphy is a safe and non-invasive screening technique for the detection of coronary artery disease and for predicting future cardiac events. The presence of ischemia correlates significantly with markers of inflammation. The discordant results (abnormal myocardial perfusion scintigraphy/normal coronary angiography) can be attributed to angiographically unrecognized occult atherosclerotic changes and abnormal vasodilatation capacity of the coronary circulation.

Changes in the Expression of Leukocyte Adhesion Molecules Throughout the Acute Phase of Myocardial Infarction

Since increased leukocytes within days after the onset of acute myocardial infarction (AMI) may reflect an increased expression of the adhesion molecules necessary for effective endothelial transmigration, we evaluated the expression of adhesion molecules on leukocytes throughout the acute phase of MI. We measured the number of leukocytes and enzymes and the expression levels of CD11a, CD18, very-late-after-activation antigen-4 alpha, intracellular adhesion molecule-1 (ICAM-1) and L-selectin by flow cytometry before and after coronary intervention, and at 6, 12, 18, 48 and 72 hours of MI in 5 patients (AMI group). As controls, we measured these parameters in 5 patients who had been diagnosed with angina pectoris and underwent coronary intervention (AP group). In the AMI group the expression of monocyte CD11a was significantly increased after 6 hours, and CD18 and ICAM-1 expression were also significantly increased after 12 hours, whereas that of monocyte L-selectin was increased after 72 hours. In addition, the increased monocyte CD11a was accompanied by an increased number of monocytes and a greater expression of CD11a per cell in the AMI group. In conclusion, since CD11a and CD18 are expressed on the cell surface as a heterodimer and ICAM-1 is a ligand for CD11a/CD18, their increased expression may contribute to their adhesion to endothelium in ischemic regions and may lead to the formation of microaggregates.

Ischemic preconditioning and lipopolysaccharide attenuate nuclear factor-kappaB activation and gene expression of inflammatory cytokines in the ischemia-reperfused rat heart

Ischemic preconditioning (IP) and pretreatment with lipopolysaccharide (LPS) reduce myocardial infarct size, but the precise mechanisms remain unknown. Rats were divided into 3 groups: the Control (C) group was subjected to 30 min ischemia followed by 3 h reperfusion; the IP and LPS groups had the same ischemia-reperfusion (I-R) insult with either preconditioning stimuli or pretreatment with LPS, respectively. Infarct size was smaller in the IP (23.4+/-2.3% of risk zone size) and LPS groups (28.5+/-2.0% of risk zone size) than in the C group (52.3+/-3.4% of risk zone size). Nuclear factor kappa-B (NF-kappaB) binding activity increased at 30 min reperfusion and declined thereafter, then rose again at 3 h reperfusion in the C group. The values in the IP (362% of control) and LPS (324% of control) groups were higher before I-R, and then decreased from 30 min (46% and 64% of control, respectively) until 3 h reperfusion (22% and 36% of control, respectively). Nuclear staining of NF-kappaB after reperfusion was less in the IP and LPS groups than in the C group. Expressions of cytokine mRNAs (interleukin-1beta, interleukin-6 and tumor necrosis factor-alpha) were detected 30 min after the onset of reperfusion and their levels remained high after 3 h of reperfusion. These expressions of cytokine mRNAs after I-R were substantially suppressed by IP and LPS, although IP and LPS alone induced modest expressions of these cytokine mRNAs. These data suggest that IP and LPS contribute to infarct size reduction via the downregulation of NF-kappaB and the attenuation of cytokine gene expression.