The C-allele of tissue inhibitor of metalloproteinases 2 is associated with increased magnitude of QT dispersion prolongation in elderly Chinese - 4-year follow-up study

Relationship of polymorphisms in the tissue inhibitor of metalloproteinase (TIMP)-1 and -2 genes with chronic heart failure

Dysregulated expression of tissue inhibitors of matrix metalloproteinases (TIMPs) is associated with systolic dysfunction and worsening heart failure (HF). However, no study has assessed the relationship between TIMP polymorphisms and chronic HF. In this study, 300 HF outpatients with reduced left ventricular ejection fraction and 304 healthy blood donors were genotyped for the 372 T > C polymorphism (Phe124Phe; rs4898) in the TIMP-1 gene and the −418 G > C polymorphism (rs8179090) in the TIMP-2 gene to investigate whether these polymorphisms are associated with HF susceptibility and prognosis. The genotype and allele frequencies of the 372 T > C polymorphism in HF patients were not significantly different from those observed among healthy subjects, and the C allele of the −418 G > C polymorphism was very rare in our population (frequency < 1%). After a median follow-up duration of 5.5 years, 121 patients (40.3%) died (67 of them from HF). Survival analysis did not show statistically significant differences in all-cause death and HF-related death between patients with and without the T allele (P > 0.05 for all comparisons). Thus, our findings do not support the hypothesis that the 372 T > C (Phe124Phe) polymorphism in the TIMP-1 gene and the −418 G > C polymorphism in the TIMP-2 gene are associated with HF susceptibility and prognosis in Southern Brazilians.

Tp-e interval and Tp-e/QTc ratio as novel surrogate markers for prediction of ventricular arrhythmic events in hypertrophic cardiomyopathy

OBJECTIVE

Hypertrophic cardiomyopathy (HCM) as a common genetic heart disease characterized by ventricular hypertrophy and myocardial fibrosis is significantly associated with a higher risk of fatal ventricular arrhythmic events (VAEs). We aimed to assess the interval between the peak and the end of the electrocardiographic T wave (Tp-e) and Tp-e/corrected QT (QTc) ratio as candidate markers of ventricular arrhythmias in patients with HCM.

METHODS

In this single-center, prospective study, a total of 66 patients with HCM and 88 controls were enrolled. The patients were divided into two groups: those with VAEs (n=26) and those without VAEs (n=40). Tp-e interval and Tp-e/QTc ratio were measured using a 12-lead electrocardiogram.

RESULTS

Tp-e interval was significantly longer and Tp-e/QTc ratio were significantly higher in HCM patients than in the controls. In correlation analysis, maximal left ventricular (LV) thickness also has a significant positive correlation with Tp-e interval (r=0.422, p<0.001) and Tp-e/QTc ratio (r=0.348, p<0.001). Finally, multivariable regression analysis showed that a history of syncope, Tp-e interval [OR (odds ratio): 1.060; 95% confidence interval (CI): 1.005-1.117); p=0.012], Tp-e/QTc ratio (OR: 1.148; 95% CI: 1.086-1.204); p=0.049], and maximal LV thickness were independent predictors of VAEs in patients with HCM.

CONCLUSION

Our findings suggested that prolonged Tp-e interval and increased Tp-e/QTc ratio may be good surrogate markers for the prediction of VAEs in HCM.

Analysis of MMP-7 and TIMP-2 gene polymorphisms in coronary artery disease and myocardial infarction: A Turkish case-control study

Matrix metalloproteinase (MMP) and tissue inhibitors of metalloproteinase (TIMP) have a significant role in tissue remodeling related to cardiac function. In earlier studies, MMP-7 A-181G (rs11568818), C-153T (rs11568819), C-115T (rs17886546), and TIMP-2 G-418C (rs8179090) polymorphisms have been studied in various diseases. However, association between coronary artery disease (CAD) and these polymorphisms has been poorly studied. The goal of this study is to investigate the association of CAD and myocardial infarction (MI) with MMP-7 or TIMP-2 polymorphisms. This study included 122 CAD patients and 132 control individuals. DNA was extracted from whole blood. Polymerase chain reaction-restriction fragment length polymorphism and automated direct sequencing method were used for genotyping of these polymorphisms. No significant differences were found between MMP-7 A-181G, C-115T, and TIMP-2 G-418C polymorphism and CAD or MI in a Turkish population. Despite the fact that the genotypes of MMP-7 C-153T polymorphism had no significant differences among MI and control groups, allele frequencies of C-153T polymorphism were significantly different between the two groups. Our study is the first report to clarify the appreciable relationship between MMP-7 C-153T polymorphism and MI development in CAD patients. However, these findings also need to be confirmed in other populations so we can improve our knowledge about the genetic factors affecting the development of CAD.

KMUP-3 attenuates ventricular remodelling after myocardial infarction through eNOS enhancement and restoration of MMP-9/TIMP-1 balance

BACKGROUND AND PURPOSE

Previously, 7-[2-[4-(4-nitrobenzene)piperazinyl]ethyl]-1, 3-dimethylxanthine (KMUP-3) has been shown to induce aortic smooth muscle relaxation through K(ATP) channel opening and endothelial nitric oxide synthase (eNOS) enhancement. We further investigated whether KMUP-3 protects against myocardial remodelling after myocardial infarction (MI), and whether KMUP-3 increases the expression of eNOS in MI rats.

EXPERIMENTAL APPROACH

Wistar rats were randomly allocated into three groups: MI (n= 10), MI + KMUP-3 group (n= 10) and sham group (n= 10). MI was induced by ligation of the left anterior descending coronary artery. After recovery, the MI + KMUP-3 group received KMUP-3 (0.3 mg·kg(-1) ·day(-1) ) infusion for 4 weeks, while the MI and sham group received vehicle only. To further confirm that the effect of KMUP-3 is dependent on eNOS, KMUP-3 was applied in the culture of transforming growth factor-β-stimulated human cardiac fibroblasts.

KEY RESULTS

KMUP-3 treatment attenuated cardiac hypertrophy post-MI and improved cardiac function. The fibrotic area was reduced by KMUP-3 both in central-, peri- and non-infarction areas. KMUP-3 enhanced the expression of eNOS and tissue inhibitor of metalloproteinase-1 (TIMP-1), but reduced matrix metalloproteinase-9 (MMP-9) expression. In vitro, the activities of KMUP-3 were blocked by pretreatment with the eNOS inhibitor N(ω) -nitro-L-arginine methyl ester.

CONCLUSIONS AND IMPLICATIONS

The K(ATP) channel opener KMUP-3 preserved cardiac function after MI by enhancing the expression of eNOS. In addition, KMUP-3 restored the myocardial MMP-9/TIMP-1 balance and attenuated ventricular remodelling by an eNOS-dependent mechanism.