Temporal changes in biomarkers and their relationships to reperfusion and to clinical outcomes among patients with ST segment elevation myocardial infarction

Effects of early myocardial reperfusion and perfusion on myocardial necrosis/dysfunction and inflammation in patients with ST-segment and non-ST-segment elevation acute coronary syndrome: results from the PLATelet inhibition and patients Outcomes (PLATO) trial

AIMS

Restoration of myocardial blood flow and perfusion during percutaneous coronary intervention (PCI) measured using Thrombolysis in Myocardial Infarction (TIMI) flow grade (TFG) and perfusion grade (TMPG) is associated with improved outcomes in acute coronary syndrome (ACS). Associations between TFG/TMPG and changes in biomarkers reflecting myocardial damage/dysfunction and inflammation is unknown.

METHODS AND RESULTS

Among 2606 patients included, TFG was evaluated in 2198 and TMPG in 1874 with ST-segment elevation myocardial infarction (STEMI) or non-ST-segment ACS (NSTE-ACS). Biomarkers reflecting myocardial necrosis [troponin T (TnT)], myocardial dysfunction [N-terminal prohormone brain natriuretic peptide (NT-proBNP)], inflammation [interleukin-6 (IL-6) and C-reactive protein (CRP)], and oxidative stress/ageing/inflammation [growth differentiation factor-15 (GDF-15)] were measured at baseline, discharge, and 1- and 6-month post-randomization. Associations between TFG/TMPG and changes in biomarker levels were evaluated using the Mann-Whitney-Wilcoxon signed test. In total, 1423 (54.6%) patients had STEMI and 1183 (45.4%) NSTE-ACS. Complete reperfusion after PCI with TFG = 3 was achieved in 1110 (85.3%) with STEMI and in 793 (88.5%) with NSTE-ACS. Normal myocardial perfusion with TMPG = 3 was achieved in 475 (41.6%) with STEMI and in 396 (54.0%) with NSTE-ACS. Levels of TnT, NT-proBNP, IL-6, CRP, and GDF-15 were substantially lower at discharge in patients with complete vs. incomplete TFG and STEMI (P < 0.01). This pattern was not observed for patients with NSTE-ACS. Patients with normal vs. abnormal TMPG and NSTE-ACS had lower levels of NT-proBNP at discharge (P = 0.01).

CONCLUSIONS

Successful restoration of epicardial blood flow in STEMI was associated with less myocardial necrosis/dysfunction and inflammation. Attainment of normal myocardial perfusion was associated with less myocardial dysfunction in NSTE-ACS.

Immunopathophysiology of trauma-related acute kidney injury

Physical trauma can affect any individual and is globally accountable for more than one in every ten deaths. Although direct severe kidney trauma is relatively infrequent, extrarenal tissue trauma frequently results in the development of acute kidney injury (AKI). Various causes, including haemorrhagic shock, rhabdomyolysis, use of nephrotoxic drugs and infectious complications, can trigger and exacerbate trauma-related AKI (TRAKI), particularly in the presence of pre-existing or trauma-specific risk factors. Injured, hypoxic and ischaemic tissues expose the organism to damage-associated and pathogen-associated molecular patterns, and oxidative stress, all of which initiate a complex immunopathophysiological response that results in macrocirculatory and microcirculatory disturbances in the kidney, and functional impairment. The simultaneous activation of components of innate immunity, including leukocytes, coagulation factors and complement proteins, drives kidney inflammation, glomerular and tubular damage, and breakdown of the blood-urine barrier. This immune response is also an integral part of the intense post-trauma crosstalk between the kidneys, the nervous system and other organs, which aggravates multi-organ dysfunction. Necessary lifesaving procedures used in trauma management might have ambivalent effects as they stabilize injured tissue and organs while simultaneously exacerbating kidney injury. Consequently, only a small number of pathophysiological and immunomodulatory therapeutic targets for TRAKI prevention have been proposed and evaluated.

Novel Biomarkers, ST-Elevation Resolution, and Clinical Outcomes Following Primary Percutaneous Coronary Intervention

Background Despite restoration of epicardial flow following primary percutaneous coronary intervention (PPCI), microvascular reperfusion as reflected by ST-elevation resolution (ST-ER) resolution remains variable and its pathophysiology remains unclear. Methods and Results Using principal component analyses, we explored associations between 91 serum biomarkers drawn before PPCI clustered into 14 pathobiologic processes (including NT-proBNP [N-terminal pro-B-type natriuretic peptide] as an independent cluster), and (1) ST-ER resolution ≥50% versus <50%; and (2) 90-day composite of death, shock, and heart failure. Network analyses were performed to understand interbiomarker relationships between the ST-ER groups. Among the 1160 patients studied, 861 (74%) had ST-ER ≥50% at a median 40 (interquartile range, 23-70) minutes following PPCI, yet both groups had comparable post-PPCI TIMI (Thrombolysis in Myocardial Infarction) grade 3 flow (86.6% versus 82.9%; P=0.25). ST-ER ≥50% was associated with significantly lower pre-PPCI concentrations of platelet activation cluster (particularly P-selectin, von Willebrand factor, and platelet-derived growth factor A) and NT-proBNP, including after risk adjustment. Across both ST-ER groups, strong interbiomarker relationships were noted between pathways indicative of myocardial stretch, platelet activation, and inflammation, whereas with ST-ER <50% correlations between iron homeostasis and inflammation were observed. Of all 14 biomarker clusters, only NT-proBNP was significantly associated with the 90-day clinical composite. Conclusions Suboptimal ST-ER is common despite achieving post-PPCI TIMI grade 3 flow. The cluster of platelet activation proteins and NT-proBNP were strongly correlated with suboptimal ST-ER and NT-proBNP was independently associated with 90-day outcomes. This analysis provides insights into the pathophysiology of microvascular reperfusion in ST-segment-elevation myocardial infarction and suggests novel pre-PPCI risk targets potentially amenable to enhancing tissue-level reperfusion following PPCI.

High-throughput targeted proteomics discovery approach and spontaneous reperfusion in ST-segment elevation myocardial infarction

BACKGROUND

Although spontaneous reperfusion (SR) prior to primary percutaneous coronary intervention (pPCI) is associated with improved outcomes, its pathophysiology remains unclear. The objective of the study was to explore associations between SR in ST-segment elevation myocardial infarction (STEMI) using a multimarker cardiovascular proteins strategy METHODS: We evaluated STEMI patients from the Assessment of Pexelizumab in Acute Myocardial Infarction trial treated with pPCI within 6 hours from symptom onset. SR was core laboratory-defined as pre-PCI Thrombolysis in Myocardial Infarction flow 2 or 3. Ninety-one cardiovascular disease-related serum biomarkers drawn prior to PCI were analyzed using a high-throughput "targeted discovery" panel. Expression levels for individual biomarkers were compared between patients with/without SR. A hierarchical clustering method of biomarkers identified clusters of biomarkers that differentiated the 2 groups. Associations between individual biomarkers and clusters with SR were further evaluated by multivariable logistic regression.

RESULTS

Of 683 patients studied, 290 had spontaneous reperfusion; those with compared to without SR were more likely noninferior STEMI and had lower clinical acuity and lower baseline levels of troponin and creatine kinase. SR was associated with a lower occurrence of 90-day composite of death, heart failure, or cardiogenic shock. Fifty-two of 91 individual biomarkers were significantly univariably associated with SR. Forty-five remained significant with adjustment for false discovery rate. Using cluster analysis, 26 biomarkers clusters were identified, explaining 72% of total covariance, and 13 biomarker clusters were significantly associated with SR after multivariable adjustment. SR was associated with higher mean expression levels of proteins in all 13 clusters. The cluster most strongly associated with SR consisted of novel proteins across various distinct, yet interlinked, pathobiological processes (kallikrein-6, matrix extracellular phosphoglycoprotein, matrix mettaloproteinaise-3, and elafin).

CONCLUSIONS

Spontaneous reperfusion prior to pPCI in STEMI was associated with a lower risk of adverse clinical events. These exploratory data from a targeted discovery proteomics platform identifies novel proteins across diverse, yet complementary, pathobiological axes that show promise in providing mechanistic insights into spontaneous reperfusion in STEMI.

CONDENSED ABSTRACT

Spontaneous reperfusion has been established with improved STEMI outcomes, yet its pathobiology is unclear and appears to involve diverse physiological processes. Using a 91-biomarker high-throughput proteomics platform, we studied 683 STEMI patients in the APEX AMI trial (290 had core laboratory-adjudicated pre-PCI TIMI 2/3 flow) and identified 52 proteins that univariably associate with spontaneous reperfusion. Cluster analysis identified 26 biomarker clusters (explaining 72% of total variance), 13 of which, after multivariable adjustment, were significantly associated with spontaneous reperfusion. Four proteins (kallikrein-6, matrix extracellular phosphoglycoprotein, matrix mettaloproteinaise-3, and elafin) across diverse, yet complementary, pathways appear to be associated most strongly with spontaneous reperfusion.

Plasma interleukin 6 levels are associated with cardiac function after ST-elevation myocardial infarction

Background and aims

Myocardial infarction triggers an inflammatory response involved in cardiac repair. We studied the association of the interleukin 6 (IL-6) cascade with infarct size and cardiac function after ST-elevation myocardial infarction (STEMI).

Methods

In 369 STEMI patients IL-6, soluble IL-6 receptor (sIL-6R), and soluble glycoprotein (sgp) 130 were measured at baseline (hospital admission), 24 h, 2 weeks, 7 weeks, 4 months, and 1 year post-PCI and sIL-6R/IL-6 ratio was calculated. At 4 months, infarct size and left ventricular ejection fraction (LVEF) were assessed by magnetic resonance imaging. Diastolic function (E/e′) was determined by echocardiography.

Results

Hospital admission levels for IL-6, sIL-6R, sgp 130 were 3.7 pg/ml (IQR 2.1–6.7 pg/ml), 51.6 ng/ml (IQR 37.3–69.0 ng/ml), and 332 ng/ml (IQR 280–399 ng/ml), respectively. 24 h after admission, IL-6 had increased threefold compared to baseline (p < 0.001) and returned below baseline (p < 0.001) 2 weeks after STEMI. sIL-6R and sgp130 levels at 24 h remained similar to baseline but were increased at 2 weeks (p < 0.001; p < 0.001, respectively). IL-6 and sIL-6R/IL-6 ratio at 24 h were independently associated with infarct size [β 5.4 (95% CI 3.3–7.5); p < 0.001, β − 4.0 (95% CI − 6.1 to − 1.9); p < 0.001, respectively]. Higher levels of IL-6 at 24 h were associated with lower LVEF [β − 4.2 (95% CI -6.7 to − 1.8); p = 0.001].

Conclusions

Higher IL-6 and lower sIL-6R/IL-6 ratio early after presentation with STEMI are indicative for larger infarct size and decreased cardiac function at 4 months.

Electronic supplementary material

The online version of this article (10.1007/s00392-018-1387-z) contains supplementary material, which is available to authorized users.

Calcium‑sensing receptors in human peripheral T lymphocytes and AMI: Cause and effect

Acute myocardial infarction (AMI) is a disease associated with inflammation. T lymphocytes are involved by secreting cytokines and inflammatory factors. In our previous study, it was found that the T lymphocytes exhibited certain functional changes, the onset of which was induced by modulating calcium‑sensing receptor (CaSR) in AMI. In the present study, western blotting was used to verified the expression of T lymphocyte CaSR and pathway proteins, including phosphorylated extracellular signal‑regulated kinase (P‑ERK)1/2 and phosphorylated c‑Jun N‑terminal kinase (P‑JNK), and used cytometric bead array to detect the secretion of interleukin (IL)‑4, IL‑6, IL‑10 and tumor necrosis factor (TNF)‑α in AMI onset, the results demonstrated that they were all increased. In addition, the expression of T lymphocyte pathway proteins, including P‑ERK1/2 and P‑JNK, and the secretion of IL‑4, IL‑6, IL‑10 and TNF‑α decreased after T lymphocytes being transfected by CaSR small interfering RNA. By contrast, the neonatal mouse cardiomyocytes under hypoxia and hypoxia/re‑oxygenation exhibited ultrastructural damage, increased apoptosis, increased production of lactate dehydrogenase (LDH) and malondialdehyde, and reduced superoxide dismutase; these indicators changed extensively when cardiomyocytes were co‑cultured with T lymphocytes. However, the effects were reversed when the cardiomyocytes were co‑cultured with CaSR‑silenced T lymphocytes. These results indicated that CaSR may modulate T lymphocytes to release cytokines through mitogen‑activated protein kinase pathways and affect cardiomyocyte injury. The relationship between AMI and T lymphocyte CaSR is reciprocal.

Contemporary Management of Cardiogenic Shock: A Scientific Statement From the American Heart Association

Cardiogenic shock is a high-acuity, potentially complex, and hemodynamically diverse state of end-organ hypoperfusion that is frequently associated with multisystem organ failure. Despite improving survival in recent years, patient morbidity and mortality remain high, and there are few evidence-based therapeutic interventions known to clearly improve patient outcomes. This scientific statement on cardiogenic shock summarizes the epidemiology, pathophysiology, causes, and outcomes of cardiogenic shock; reviews contemporary best medical, surgical, mechanical circulatory support, and palliative care practices; advocates for the development of regionalized systems of care; and outlines future research priorities.

Dexrazoxane Shows No Protective Effect in the Acute Phase of Reperfusion during Myocardial Infarction in Pigs

Calcium and iron overload participate in the mechanisms of ischemia/reperfusion (I/R) injury during myocardial infarction (MI). Calcium overload induces cardiomyocyte death by hypercontraction, while iron catalyses generation of reactive oxygen species (ROS). We therefore hypothesized that dexrazoxane, an intracellular metal chelator, would attenuate I/R injury. MI was induced in pigs by occlusion of the left anterior descending artery for 1 hour followed by 2 hours reperfusion. Thirty minutes before reperfusion either 5 mg/ml dexrazoxane (n = 5) or saline (n = 5) was infused intravenously. Myocardial necrosis as percentage of the area at ischemic risk was found to be similar in both groups (77.2 ± 18% for dexrazoxane and 76.4 ± 14% for saline group) as determined by triphenyl tetrazolium chloride staining of the ischemic myocardium. Also, serum levels of troponin-I were similar in both groups. A conductance catheter was used to measure left ventricular pressure and volume at all times. Markers for tissue damage due to ROS (HNE), endothelial cell activation (CD31) and inflammation (IgG, C3b/c, C5b9, MCP-1) were assessed on tissue and/or in serum. No significant differences were observed between the groups for the parameters analyzed. To conclude, in this clinically relevant model of early reperfusion after acute myocardial ischemia, dexrazoxane lacked attenuating effects on I/R injury as shown by the measured parameters.