Linfopenia post-reperfusión y obstrucción microvascular en el infarto agudo de miocardio con elevación del segmento ST

Changes in the extracellular matrix at microvascular obstruction area after reperfused myocardial infarction: A morphometric study

BACKGROUND

Extracellular matrix (ECM) suffers substantial alterations after myocardial infarction (MI), including the invasion of leukocyte subtypes. Despite a complete reopening at epicardial level, hypoperfusion within the infarcted myocardium, known as microvascular obstruction (MVO), occurs and exerts a negative impact on ventricular remodeling. In this study, ECM composition at MVO regions was described using a morphometric analysis.

METHODS

MI was induced in female swine (n = 10) by transitory 90-minute coronary occlusion followed by seven days of reperfusion. Prior to euthanasia, intracoronary thioflavin-S was infused. Within the infarcted myocardium, regions displaying MVO (thioflavin-S-) or no MVO (thioflavin-S+) were isolated and stained to morphometrically compare ECM composition.

RESULTS

As reflected by cell invasion through ECM, areas with MVO displayed an enlarged presence of neutrophils and lymphocytes, whilst no differences in the amount of macrophages and myofibroblasts were detected compared to infarcted myocardium without MVO. Indeed, those regions with macroscopic MVO showed lower capillary density than areas without MVO. Lastly, a significant reduction in the extension of total collagen, type I, but not type III, collagen, laminin, and fibronectin together with an augmentation of polysaccharides were noted in areas showing MVO compared to those without microvascular injury.

CONCLUSIONS

ECM composition in infarcted regions with MVO isolated from female swine displays a higher presence of inflammatory infiltrate and polysaccharides as well as reduced number of microvessels and collagen content compared to those areas without microvascular hypoperfusion. These characteristics might underlie the development of adverse ventricular remodeling in MI patients with extensive MVO.

Increased Platelet-to-Lymphocyte Ratio is an Independent Predictor of Hemorrhagic Transformation and In-Hospital Mortality Among Acute Ischemic Stroke with Large-Artery Atherosclerosis Patients

Background

The platelet-to-lymphocyte ratio (PLR) is an inflammation marker of acute ischemic stroke, but its significance in patients with hemorrhage transformation (HT) after acute ischemic stroke with large-artery atherosclerosis (AIS-LAA) is unclear, and we also identified the relationship between PLR and in-hospital mortality of HT after AIS-LAA.

Methods

This was a retrospective analysis of patients with AIS-LAA. The PLR was calculated according to platelet and lymphocyte counts on admission. HT was defined on follow-up magnetic resonance imaging or computed tomography when neurologic deterioration worsened during hospitalization. The univariate analysis and multivariate logistic regression were performed to assess the association of PLR, HT and in-hospital mortality of HT after AIS-LAA.

Results

We included 328 Chinese AIS-LAA patients (mean age 67.2±11.1 years; 70.4% male). HT occurred in 38 patients (11.6%). After multivariate regression analyses, NRL (odds ratio [OR] 1.354, 95% confidence interval [CI] 1.176–1.559, P<0.001) and PLR (odds ratio [OR] 3.869, 95% confidence interval [CI] 2.233–5.702, P<0.001) were independently associated with HT after AIS-LAA. The area under the ROC curve (AUC) value of PLR (0.72, 95% CI (0.64–0.80), P<0.001) tested a greater discriminatory ability compared with neutrophil-lymphocyte ratio (NLR) (0.67, 95% CI (0.58–0.76), P<0.001). Meanwhile, PLR was found to be significantly related to HT after AIS-LAA, including in subtypes of artery-to-artery embolization (aOR 1.699, 95% CI 1.298–3.215, P<0.001), in-situ thrombosis (aOR4.499, 95% CI 1.344–9.054, P<0.001) and branch atheromatous disease (aOR3.239, 95% CI 1.098–8.354, P<0.001). Increased PLR predicts high in-hospital mortality of HT after AIS-LAA (OR 1.041, 95% CI (1.006–1.077), P=0.020; aOR 1.053, 95% CI (1.004–1.104), P=0.034).

Conclusion

High PLR is associated with greater risk of HT in AIS-LAA patients, including in artery-to-artery embolization, in-situ thrombosis and branch atheromatous disease. Meanwhile, increased PLR predicts high in-hospital mortality of HT after AIS-LAA.

Overexpression of genes involved in lymphocyte activation and regulation are associated with reduced CRM-derived cardiac remodelling after STEMI

AIMS

Lymphopenia after ST-segment elevation myocardial infarction (STEMI) correlates with deleterious cardiac consequences and worse prognosis. An in-depth examination of genes implicated in lymphocyte proliferation, activation and regulation and their association with short- and long-term cardiac structure and function is therefore of great interest.

METHODS

Peripheral blood mononuclear cells were isolated from 10 control subjects and 64 patients with a first STEMI treated with primary percutaneous coronary intervention and submitted to cardiac magnetic resonance after 1 week and 6 months. mRNA expression of genes implicated in lymphocyte activation (CD25 and CD69) and regulation [programmed death (PD)-1 and cytotoxic T-lymphocyte antigen (CTLA)-4] were determined by qRT-PCR.

RESULTS

In comparison to controls, STEMI patients showed heightened mRNA expression of CD25 and lower PD-1 and CTLA-4 96 h after coronary reperfusion. Patients with extensive infarctions (>30% of left ventricular mass) at 1 week displayed a notable reduction in CD25, CD69, PD-1, and CTLA-4 expression (p < 0.05). However, CD25 was the only predictor of 1-week extensive infarct size in multivariate logistic regression analysis (odds ratio 0.019; 95% confidence interval [0.001-0.505]; p = 0.018). Regarding long-term ventricular function, mRNA expression of CD25 under the mean value was associated with worse ventricular function and more adverse remodelling.

CONCLUSIONS

Following STEMI, heightened expression of genes expressed in regulatory T cells (CD25 and CD69) and immune checkpoints (PD-1 and CTLA-4) correlates with a better short- and long-term cardiac structure and function. Advancing understanding of the pathophysiology of lymphopenia and evaluating novel immunomodulatory therapies will help translate these results into future clinical trials.

Similar Clinical Course and Significance of Circulating Innate and Adaptive Immune Cell Counts in STEMI and COVID-19

This study aimed to assess the time course of circulating neutrophil and lymphocyte counts and their ratio (NLR) in ST-segment elevation myocardial infarction (STEMI) and coronavirus disease (COVID)-19 and explore their associations with clinical events and structural damage. Circulating neutrophil, lymphocyte and NLR were sequentially measured in 659 patients admitted for STEMI and in 103 COVID-19 patients. The dynamics detected in STEMI (within a few hours) were replicated in COVID-19 (within a few days). In both entities patients with events and with severe structural damage displayed higher neutrophil and lower lymphocyte counts. In both scenarios, higher maximum neutrophil and lower minimum lymphocyte counts were associated with more events and more severe organ damage. NLR was higher in STEMI and COVID-19 patients with the worst clinical and structural outcomes. A canonical deregulation of the immune response occurs in STEMI and COVID-19 patients. Boosted circulating innate (neutrophilia) and depressed circulating adaptive immunity (lymphopenia) is associated with more events and severe organ damage. A greater understanding of these critical illnesses is pivotal to explore novel alternative therapies.

Prognostic nutritional index predicts in-hospital mortality in patients with acute Stanford type A aortic dissection

BACKGROUND

Acute Stanford type A aortic dissection (ATAAD) is a life-threatening medical emergency. The aim of this study was to investigate the clinical significance of the prognostic nutritional index (PNI) as a novel inflammatory marker for ATAAD patients undergoing surgical repair.

METHODS

We retrospectively examined the medical records of 151 ATAAD patients who treated surgically. Patients were divided into two groups (survival and death) and these groups were compared with respect to clinical and laboratory parameters. The PNI was calculated as 10 × serum albumin (g/dL) + 0.005 × total lymphocyte count (per mm³). Logistic regression analyses were performed to identify the risk factors of in-hospital mortality.

RESULTS

The mean age of the study cohort was 61 ± 12 years, 99 (65.6%) were males, and 35 (23.2%) patients died during the hospital stay. The PNI levels were significantly lower in death group compared with survival group (32.80 ± 4.90 vs. 37.94 ± 5.42, p < 0.001). Multivariate analysis showed that the PNI (OR: 0.795, p = 0.005), age (odds ratio [OR]: 1.085, p = 0.034), operating time (OR: 1.660, p = 0.042), and D-dimer (OR: 1.002, p = 0.001) independently predicted in-hospital mortality. The calculated cutoff value of the PNI was 33.01.

CONCLUSION

Lower PNI values are independently associated with in-hospital mortality in ATAAD. The PNI may be a useful tool for predicting the early mortality of ATAAD patients after surgical repair.

Lymphocyte Communication in Myocardial Ischemia/Reperfusion Injury

SIGNIFICANCE

Myocardial ischemia/reperfusion (I/R) is an important complication of reperfusion therapy for myocardial infarction (MI). It is a complex process involving metabolic and immunological factors. To date, no effective treatment has been identified. Recent Advances: Previous research has focused on the role of innate immune cells in I/R injury. In recent years, increasing evidence has accumulated for an important role for adaptive immune cells, particularly T lymphocytes. Data from ST elevation MI patients have identified prognostic significance for lymphocyte counts, particularly postreperfusion lymphopenia. Dynamic changes in circulating CD4⁺ T cell subsets occurring early after reperfusion are associated with development of I/R injury in the form of microvascular obstruction. Transcoronary gradients in cell counts suggest sequestration of these cells into the reperfused myocardium. These findings support existing data from mouse models indicating a role for CD4⁺ T cells in I/R injury. It is clear, however, the effects of lymphocytes in the ischemic myocardium are time and subset specific, with some having protective effects, while others are pathogenic.

CRITICAL ISSUES

An understanding of the cellular events that lead to accumulation of lymphocytes in the myocardium, and their actions once there, is key to manipulating this process. Chemokines produced in response to ischemia and cellular injury have an important role, while lymphocyte-derived cytokines are critical in the balance between inflammation and healing.

FUTURE DIRECTIONS

Further research into the involvement of lymphocytes in myocardial I/R injury may allow development of targeted therapies, opening a new avenue of considerable therapeutic potential. Antioxid. Redox Signal. 26, 660-675.

Neutrophil to Lymphocyte Ratio Is Related to Electrocardiographic Sign of Spontaneous Reperfusion in Patients with ST-segment Elevation Myocardial Infarction

BACKGROUND AND AIMS

ST-segment resolution ≥70% on consecutive electrocardiograms (ECGs) before administration of definitive reperfusion therapy is considered as an electrocardiographic sign of spontaneous reperfusion (SR) in STEMI patients and it indicates not only the patency of the infarct-related artery (IRA) but also the microvascular and myocardial reperfusion. Neutrophil/lymphocyte (N/L) ratio has been demonstrated to be associated with the patency of the IRA and no-reflow in patients with STEMI before mechanical reperfusion therapy. However, the association between N/L ratio and ST-segment resolution in STEMI patients with SR was not investigated. The aim of this study was to focus on the relation between N/L ratio and ST-segment resolution in STEMI patients with SR.

METHODS

One hundred sixty two consecutive patients with their first diagnosed STEMI were enrolled in this study. ECGs of all the patients at admission and 1 h later were obtained. According to electrocardiographic sign of SR, the patients were divided into two groups as SR group and non-SR group. Clinical data between two groups were evaluated.

RESULTS

Patients in SR group had lower neutrophil counts, higher lymphocyte counts, and lower N/L ratio than patients in non-SR group. Moreover, after undertaking primary PCI, patients in SR group had lower peak cTnT value and higher LVEF than patients in non-SR group. Furthermore, N/L ratio was an independent predictor of electrocardiographic sign of SR in patients with STEMI.

CONCLUSION

N/L ratio, an easily available laboratory data, may be related to microvascular reperfusion in STEMI patients with electrocardiographic sign of SR.

[Comparative study of functional and structural changes produced in a porcine model of acute and chronic heart attack]

INTRODUCTION AND OBJECTIVES

Animal models are a useful tool for the evaluation of disease mechanisms and also for technologies for diagnosis and treatment. In this study we performed a descriptive analysis of the functional and structural cardiac changes occurred as a result of acute coronary occlusion in pigs and its evolution during 5 weeks.

METHODS

19-Large White pigs, weighing 20kg, randomized into 3-experimental series were used. After sternotomy, anterior descending coronary artery was occluded. Duration of occlusion: Series 1 (n=6) 60min; series 2 (n=8) 90min; series 3 (n=5) 60min followed for 5 weeks. The following parameters where then analyzed: global cardiac function (ECG, left ventricular and atrium pressures, aortic flow and cardiac echocardiography), regional contractility, troponin T and CK-MB levels, macroscopic and histological analyzes.

RESULTS

Coronary occlusion transiently altered the global cardiac function and produced increased cell damage markers, impaired regional contractility and produced histological changes. The increment of ischemic time (60 vs. 90min) increased infarct size (13.4±5.4% vs. 22.9±7.8 S1 S2%; P=.04). After 5 weeks, morphological remodelling changes were evident. In 79% of cases ischemia triggered ventricular fibrillation.

CONCLUSION

The porcine open chest model of acute myocardial infarction and reperfusion is valid for studying the pathophysiology of coronary ischemia, allows direct analysis of regional myocardial function and is easily retrievable in the event of serious arrhythmias.

T lymphocytes and fractalkine contribute to myocardial ischemia/reperfusion injury in patients

BACKGROUND

Lymphocytes contribute to ischemia/reperfusion (I/R) injury in several organ systems, but their relevance in ST elevation myocardial infarction (STEMI) is unknown. Our goal was to characterize lymphocyte dynamics in individuals after primary percutaneous coronary intervention (PPCI), assess the prognostic relevance of these cells, and explore mechanisms of lymphocyte-associated injury.

METHODS

Lymphocyte counts were retrospectively analyzed in 1,377 STEMI patients, and the prognostic relevance of post-PPCI lymphopenia was assessed by Cox proportional hazards regression. Blood from 59 prospectively recruited STEMI patients undergoing PPCI was sampled, and leukocyte subpopulations were quantified. Microvascular obstruction (MVO), a component of I/R injury, was assessed using MRI.

RESULTS

In the retrospective cohort, lymphopenia was associated with a lower rate of survival at 3 years (82.8% vs. 96.3%, lowest vs. highest tertile; hazard ratio 2.42). In the prospective cohort, lymphocyte counts fell 90 minutes after reperfusion, primarily due to loss of T cells. CD8+ T cells decreased more than CD4+ T cells, and effector subsets exhibited the largest decline. The early decrease in effector T cell levels was greater in individuals that developed substantial MVO. The drop in T cell subsets correlated with expression of the fractalkine receptor CX3CR1 (r2 = 0.99, P = 0.006). Serum fractalkine concentration peaked at 90 minutes after reperfusion, coinciding with the T cell count nadir.

CONCLUSIONS

Lymphopenia following PPCI is associated with poor prognosis. Our data suggest that fractalkine contributes to lymphocyte shifts, which may influence development of MVO through the action of effector T cells.

TRIAL REGISTRATION

Not applicable.

FUNDING

British Heart Foundation (FS/12/31/29533) and National Institute of Health Research (NIHR) Newcastle Biomedical Research Centre.

Splenic leukocytes mediate the hyperglycemic exacerbation of myocardial infarct size in mice

Acute hyperglycemia during acute myocardial infarction is associated with worse myocardial injury and increased mortality. Using a mouse model of myocardial ischemia/reperfusion injury, we tested the hypothesis that acute hyperglycemia activates splenic leukocytes and subsequently exacerbates myocardial infarct size. We then examined whether the adverse effects of hyperglycemia could be attenuated by a potent anti-inflammatory agent (an agonist of the adenosine A2A receptor) administered immediately prior to reperfusion. C57BL6 (WT) mice underwent 30-min LAD occlusion and 60-min reperfusion with or without prior splenectomy. Acute hyperglycemia before ischemia increased myocardial infarct size (IS) by 43% (p < 0.05). Splenectomy before ischemia did not change IS (vs. control, p = NS) but did serve to prevent the exacerbation of IS by hyperglycemia. Acute hyperglycemia activated splenic leukocytes by increasing formyl peptide receptor expression and reactive oxygen species production before ischemia, and enhanced splenic neutrophil release with resultant peripheral neutrophilia and increased myocardial neutrophil infiltration during reperfusion. Acute adoptive transfer of splenic leukocytes to splenectomized mice before ischemia restored the hyperglycemic exacerbation of infarct size. ATL146e, an adenosine 2A receptor (A2AR) agonist, abolished neutrophilia during reperfusion and reduced IS in hyperglycemic mice. ATL146e also reduced IS in splenectomized hyperglycemic mice with transfer of WT splenic leukocytes, but not with transfer of splenic leukocytes from A2AR knockout mice. Acute hyperglycemia prior to myocardial ischemia and reperfusion exacerbates IS by activating splenic leukocytes. ATL146e administered at reperfusion suffices to abrogate the hyperglycemic exacerbation of IS by acting on A2ARs on splenic leukocytes.

Inflammatory markers in ST-elevation acute myocardial infarction

After acute myocardial infarction, ventricular remodeling is characterized by changes at the molecular, structural, geometrical and functional level that determine progression to heart failure. Inflammation plays a key role in wound healing and scar formation, affecting ventricular remodeling. Several, rather different, components of the inflammatory response were studied as biomarkers in ST-elevation acute myocardial infarction. Widely available and inexpensive tests, such as leukocyte count at admission, as well as more sophisticated immunoassays provide powerful predictors of adverse outcome in patients with ST-elevation acute myocardial infarction. We review the value of inflammatory markers in ST-elevation acute myocardial infarction and their association with ventricular remodeling, heart failure and sudden death. In conclusion, the use of these biomarkers may identify subjects at greater risk of adverse events and perhaps provide an insight into the mechanisms of disease progression.

The sum of ST-segment elevation is the best predictor of microvascular obstruction in patients treated successfully by primary percutaneous coronary intervention. Cardiovascular magnetic resonance study

INTRODUCTION AND OBJECTIVES

The usefulness of ST-segment elevation resolution (STR) for predicting epicardial reperfusion is well established. However, it is still not clear how ST-segment changes are related to microvascular obstruction (MVO) observed by cardiovascular magnetic resonance (CMR) after primary percutaneous coronary intervention (pPCI) for ST-segment elevation myocardial infarction (STEMI).

METHODS

The study involved 85 consecutive patients admitted for a first STEMI and treated by pPCI who had a patent infarct-related artery. An ECG was recorded on admission and 90 min and 6, 24, 48 and 96 h after pPCI. Thereafter, STR and the sum of ST-segment elevation (sumSTE) in all leads were determined.

RESULTS

Overall, CMR revealed MVO in 37 patients. In infarcts with MVO, sumSTE was greater both before and after revascularization than in infarcts without MVO (P≤.001 at all times). In contrast, there was no significant difference in the magnitude of STR between infarcts with and without MVO 90 min after revascularization (P=.1), though there was after 6 h (P< .05 at all times). The area under the receiver operating characteristic curve for detecting MVO was greater for sumSTE than STR (P< .05 for all measurements). On multivariate analysis, after adjusting for clinical, angiographic and ECG characteristics, a sumSTE >3 mm 90 min after pPCI was an independent predictor of MVO on CMR, while an STR ≥70% was not (odds ratio=3.1; 95% confidence interval, 1.2-8.4; P=.02).

CONCLUSIONS

MVO was associated with a significantly increased sumSTE at all times after revascularization. The difference in the magnitude of STR between infarcts with and without MVO was significant only >6 h after revascularization. The best predictor of MVO was a sumSTE >3 mm 90 min after pPCI.