Association of Thrombospondin-1 (N700S) and Thrombospondin-4 (A387P) Gene Polymorphisms with the Incidence of Acute Myocardial Infarction in Egyptians

Abstract

Background: Thrombospondin (TSP) 1 and 4 are extracellular matrix glycoproteins that me- diate cell proliferation, platelet aggregation and inflammatory response. Conflicting data addressed the possible contribution of TSP-1 and TSP-4 gene polymorphisms to acute myocardial infarction (AMI).

Objective: Our study aimed to examine the association of TSP-1 (N700S) and TSP-4 (A387P) genetic variants with the incidence of AMI in Egyptians. It also correlated TSP-1 variants to TSP-1 and TNF-α serum concentrations while TSP-4 variants to IL-8 concentration identifying TSPs' contribution to vascular inflammation.

Methods: Genotyping was done in 214 subjects; 114 AMI patients and 100 controls using PCR-RFLP analysis. Serum Tsp-1, TNF-α and IL-8 levels were measured by ELISA assay.

Results: For TSP-4, (GC and CC) genotype distribution and the (C) allele frequency were significantly higher in AMI patients than controls (p = 0.0186), (p = 0.0117) respectively. In contrast, TSP-1 genotypes and allele frequencies showed no significant difference between AMI and controls (p = 0.7124 and p = 0.7201, respectively). Serum TSP-1, TNF-α and IL-8 concentrations were significantly elevated in AMI compared to controls (p = 0.0146, p < 0.0001 and p = 0.0057) respectively. Serum IL-8 levels had a significant difference among TSP-4 genotypes (p= 0.0368), being highest in the mutant C allele. Serum TSP-1 and TNF-α concentrations showed no significant difference among TSP-1 genotypes, but there was a positive correlation between both concentrations in AMI patients (p = 0.0014), (r = 0.4125).

Conclusion: TSP-4 A387P polymorphism, but not TSP-1 polymorphism, is an independent risk factor for AMI in the Egyptians.

Keywords: Acute myocardial infarction; Egyptians; PCR-RFLP; interleukin-8; polymorphism; thrombospondin; tumor necrosis factor alpha.