Mild hyperhomocysteinemia is associated with a decreased fibrinolytic activity in patients after ST-elevation myocardial infarction

Biomarkers of Thrombotic Status Predict Spontaneous Reperfusion in Patients With ST-Segment Elevation Myocardial Infarction

BACKGROUND

Spontaneous reperfusion, seen in ∼20% of patients with ST-segment elevation myocardial infarction (STEMI), manifests as normal epicardial flow in the infarct-related artery, with or without ST-segment resolution, before percutaneous coronary intervention (PCI). The drivers mediating this are unknown.

OBJECTIVES

The authors sought to relate spontaneous reperfusion to the thrombotic profile.

METHODS

In a prospective study, blood from STEMI patients (n = 801) was tested pre-PCI to assess in vitro, point-of-care, occlusion times (OT) and endogenous lysis times (LT). Spontaneous reperfusion was defined as infarct-related artery Thrombolysis In Myocardial Infarction flow grade 3 before PCI. Patients were followed for major cardiovascular events (death, myocardial infarction, or stroke).

RESULTS

Spontaneous reperfusion was associated with a longer OT (435 seconds vs 366 seconds; P < 0.001) and a shorter LT (1,257 seconds vs 1,616 seconds; P < 0.001), lower troponin, and better left ventricular function. LT was superior to OT for predicting spontaneous reperfusion (area under the curve for LT: 0.707; 95% CI: 0.661-0.753; area under the curve for OT: 0.629; 95% CI: 0.581-0.677). Among patients with spontaneous reperfusion, those with complete, vs partial ST-segment resolution, had a longer OT (P = 0.002) and a shorter LT (P < 0.001). Spontaneous reperfusion was unrelated to clinical characteristics or pain-to-angiography times. Over 4 years, patients with spontaneous reperfusion experienced fewer major adverse cardiovascular events than those without (4.1% vs 10.6%; P = 0.013), especially in those with both spontaneous reperfusion and complete ST-segment resolution (1.5% vs 10.1%; P = 0.029).

CONCLUSIONS

We demonstrate a novel hematological signature in STEMI patients with spontaneous reperfusion, namely, decreased platelet reactivity and faster endogenous fibrinolysis, relating to smaller infarcts and improved survival. This finding indicates a role for modulating thrombotic status early after STEMI onset, to facilitate spontaneous reperfusion and improve outcomes.

Lipoprotein(a)—The Crossroads of Atherosclerosis, Atherothrombosis and Inflammation

Increased lipoprotein(a) (Lp(a)) levels are an independent predictor of coronary artery disease (CAD), degenerative aortic stenosis (DAS), and heart failure independent of CAD and DAS. Lp(a) levels are genetically determinated in an autosomal dominant mode, with great intra- and inter-ethnic diversity. Most variations in Lp(a) levels arise from genetic variations of the gene that encodes the apolipoprotein(a) component of Lp(a), the LPA gene. LPA is located on the long arm of chromosome 6, within region 6q2.6–2.7. Lp(a) levels increase cardiovascular risk through several unrelated mechanisms. Lp(a) quantitatively carries all of the atherogenic risk of low-density lipoprotein cholesterol, although it is even more prone to oxidation and penetration through endothelia to promote the production of foam cells. The thrombogenic properties of Lp(a) result from the homology between apolipoprotein(a) and plasminogen, which compete for the same binding sites on endothelial cells to inhibit fibrinolysis and promote intravascular thrombosis. LPA has up to 70% homology with the human plasminogen gene. Oxidized phospholipids promote differentiation of pro-inflammatory macrophages that secrete pro-inflammatory cytokines (e. g., interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor-α). The aim of this review is to define which of these mechanisms of Lp(a) is predominant in different groups of patients.

Homocysteine and long-term recurrent infarction following an acute coronary syndrome

BACKGROUND

There are no well-established predictors of recurrent ischemic coronary events after an acute coronary syndrome (ACS). Higher levels of homocysteine have been reported to be associated with an increased atherosclerotic burden. The primary endpoint was to assess the relationship between homocysteine at discharge and very long-term recurrent myocardial infarction (MI).

METHODS

1306 consecutive patients with ACS were evaluated (862 with non-ST-segment elevation ACS [NSTEACS] and 444 with ST-segment elevation myocardial infarction [STEMI]) discharged from October 2000 to June 2003 in a single teaching-center. The relationship between homocysteine at discharge and recurrent MI was evaluated through bivariate negative binomial regression accounting for mortality as a competitive event.

RESULTS

The mean age was 66.8 ± 12.4 years, 69.1% were men, and 32.2% showed prior diabetes mellitus. Most of the patients were admitted for an NSTEACS (66.0%). The median (interquartile range) GRACE risk score, Charlson comorbidity index, and homocysteine were 144 (122-175) points, 1 (1-2) points, and 11.9 (9.3-15.6) μmol/L, respectively. In-hospital revascularization was performed in 26.3% of patients. At a median follow-up of 9.7 (4.5-15.1) years, 709 (54.3%) deaths were registered and 779 recurrent MI in 478 (36.6%) patients. The rates of recurrent MI were higher in patients in the upper homocysteine quartiles (p < 0.001). After a multivariate adjustment, homocysteine along its continuum remained almost linearly associated with a higher risk of recurrent MI (p = 0.001) and all-cause mortality (p < 0.001).

CONCLUSIONS

In patients with ACS, higher homocysteine levels identified those at a higher risk of recurrent MI at very long-term follow-up.

Effects of Sulfur Amino Acids on Cardiodynamic Parameters of Isolated Rat Heart

Sulfur-containing amino acids are integral part of molecular mechanisms which underlie many aspects of cellular function and homeostasis, facilitated by reversible changes in oxidation states of sulfur atoms. Dysregulation of these pathways is associated with diverse pathologies, notably of the cardiovascular system, which are typically characterized by inappropriate plasma levels of sulfur-containing amino acids. The aim of this study was to assess the acute, direct effects of sulfur-containing amino acids and inorganic NaHS, as H2S donor, on cardiodynamic parameters in homocysteine treated rats. Moderate hyperhomocysteinemia did not cause significant decrease in myocardial contractility, but our findings suggest that NaHS and L-methionine cause negative effects on cardiac function in hearts of the rats treated with homo-cysteine, even in a single administration. Further investigations need to be carried out with purpose of better understanding and highlightening the impact of Hcy and sulphur amino acids on cardiac function.

Admission homocysteine is an independent predictor of spontaneous reperfusion and early infarct-related artery patency before primary percutaneous coronary intervention in ST-segment elevation myocardial infarction

Background

Spontaneous reperfusion (SR) and early infarct related artery (IRA) patency before primary percutaneous coronary intervention (PPCI) might bring extra benefit for patients with ST-segment elevation myocardial infarction (STEMI). This study premilinarily screened the independent predictors of SR, and assessed the relationship between SR and plasma homocysteine (HCY).

Methods

The medical records of 998 patients who were diagnosed as STEMI and underwent emergency coronary angiography were retrospectively studied, SR was defined as achievement of TIMI grade 3 flow in the IRA before PCI. The baseline characteristics, clinical manifestations and hematological variables were compared between SR and NSR group. Optimal cutoff point of HCY was calculated with receiving operating characteristics (ROC) analysis, multivariate logistic regression models were used to identify predictors of SR.

Results

229 (22.95%) patients showed angiographic SR. For HCY, the area under the curve was 0.70 (95% CI: 0.63–0.77, P = 0.034), the optimized cut off point was 17.55 μmol/L. Preinfarct angina (95% CI: 1.61–5.65, P = 0.0005), plasma C-reactive protein (CRP) level (95% CI: 0.87–0.99, P = 0.016) and HCY < 17.55 μmol/L (95% CI: 2.43–8.72, P < 0.0001) were found to be independent predictors for SR.

Conclusion

In patients with STEMI, HCY < 17.55 μmol/L, preinfarct angina and plasma CRP level were independent predictors of SR.

The effects of L-cysteine and N-acetyl-L-cysteine on homocysteine metabolism and haemostatic markers, and on cardiac and aortic histology in subchronically methionine-treated Wistar male rats

Methionine is the precursor of homocysteine, a sulfur amino acid intermediate in the methylation and transsulfuration pathways; methionine-rich diets were used to induce hyperhomocysteinemia, and cardiovascular pathology was often observed. Other sulfur amino acids interfere with this metabolism, i.e., L-cysteine (Cys) and N-aceyl-L-cysteine (NAC), and probably also affect cardiovascular system. Their effects are controversial due to their ability to act both as anti- or pro-oxidant. Thus, this study aimed to elucidate their influence on levels of homocysteine, folate and vitamin B12, levels of different haemostatic parameters (fibrinogen, D-dimer, vWF Ag, vWF Ac) in rat serum or plasma as well as their effects on cardiac and aortic tissue histology in subchronically methionine-treated rats. Wistar albino rats were divided into 4 experimental groups: (a) control group (0.9% sodium chloride 0.1-0.2 mL/day) (n = 10) (K); (b) DL-methionine (0.8 mmol/kg/bw/day) (n = 10) (M); (c) DL-methionine (0.8 mmol/kg/bw/day) + L-cysteine (7 mg/kg/bw/day) (n = 8) (C); (d) DL-methionine (0.8 mmol/ kg/bw/day) + N-acetyl-L-cysteine (50 mg/kg/bw/day) (n = 8) (N). All substances were applied i.p., treatment duration 3 weeks. Lower levels of vitamin B12 in all the groups were found. Folate was reduced only in N group. Decreased fibrinogen was noted in C and N groups and increased D-dimer only in C. VWF activity was reduced in M and C groups. Deleterious effects in heart were observed, especially after Cys and NAC application. Aortic tissue remained unchanged. In conclusion, it could be said that sulfur amino acids have the significant impact on cardiovascular system in subchronically methionine-treated rats. This study points out the relevance of their complex interactions and deleterious effects mediated by either direct influence or procoagulant properties.

Homocysteine has anti-inflammatory properties in a hypercholesterolemic rat model in vivo

Inflammation is a hallmark in many neurodegenerative diseases like Alzheimer's disease or vascular dementia. Cholesterol and homocysteine are both vascular risk factors which have been associated with dementia, inflammation and blood–brain barrier dysfunction. In previous studies we found that hypercholesterolemia but not hyperhomocysteinemia induced inflammation in rats in vivo. The aim of the present study was to investigate the effect of a combined treatment of Sprague Dawley rats with cholesterol and homocysteine for 5 months on spatial learning and memory, blood–brain barrier integrity and inflammation. Cholesterol treated rats showed severe learning deficits, while rats treated with cholesterol and homocysteine (Mix) counteracted the cholesterol-induced inflammation and partly the cortical blood–brain barrier disruptions, although cognition was still impaired. To study the potential protective effect of homocysteine, inflammation was induced in organotypic rat brain cortex slices and primary microglial cells by treatment with different inflammatory stimuli (e.g. lipopolysaccharide or tissue plasminogen activator). Tissue plasminogen activator-induced inflammation was counteracted by homocysteine. In conclusion, our data demonstrate that homocysteine significantly ameliorates cholesterol-induced inflammation and blood–brain barrier disruption but not the memory impairment, possibly involving a tissue plasminogen activator-related mechanism.

Plasma homocysteine level and left ventricular thrombus formation in acute anterior myocardial infarction patients following thrombolytic therapy with t-PA

AIMS

The aim of this study was to evaluate the relationship between homocysteine levels and the development of left ventricular thrombus in acute anterior myocardial infarction patients directed to thrombolytic therapy.

METHODS AND RESULTS

Seventy-nine patients presenting with ST elevated acute anterior myocardial infarction and treated with thrombolytic agent, t-PA, were included in the study. Two-dimensional echocardiography was used to divide patients into 2 groups according to the presence (n = 14) or absence (n = 65) of thrombus in the left ventricle following myocardial infarction. The levels of fasting plasma total homocysteine, total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, vitamin B12 and folic acid were assessed. There were no significant differences between two groups in terms of age, gender, hyperlipidemia and smoking. History of diabetes mellitus (28.57% versus 6.15%, p = 0.04), peak creatine phosphokinase levels (4153.54 +/- 1228.41 U/L versus 2456.92 +/- 1421.36 U/L, p < 0.001), mean left ventricular wall motion score index (2.21 +/- 0.18 versus 1.83 +/- 0.23, p < 0.001) and total fasting homocysteine levels (18.24 +/- 5.67 mmol/L versus 12.31 +/- 3.52 mmol/L, p < 0.001) were significantly higher in patients with left ventricular thrombus. In multivariate analysis; only diabetes mellitus (p = 0.03), higher wall motion score index (p = 0.001) and higher homocysteine levels (p = 0.04) were independent predictors of left ventricular thrombus formation.

CONCLUSION

Our results suggest that; diabetes mellitus, higher wall motion score index and hyperhomocysteinemia independently increases the risk for the development of left ventricular thrombus formation in patients with acute anterior myocardial infarction following thrombolytic therapy.