Oxidized LDL, Oxidized LDL Receptor 1 (OLR1) Gene Polymorphism With Oxygen Therapy in Acute Myocardial Infarction.

Cardiovascular disease, which is multifactorial and caused by complex interactions of genetic and environmental factors, represents the main cause of death all over the world. Traditional risk factors for coronary atherosclerosis include age, smoking, male gender, hypertension and diabetes. Newly defined risk factors such as hyper-homocysteine, elevated plasma levels of OxLDL and oxidative stress are also emerging.

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is the major receptor of oxidized low-density lipoproteins which regulates the growth of a variety of cells and is important in inflammation, atherosclerosis, oxidative stress, and tissue remodeling. LOX-1 is expressed in various cells, including endothelial cells, macrophages, and chondrocytes, and its expression is enhanced by proinflammatory cytokines. The LOX1 gene, also known as OLR1, is located on the chromosome 12p13.1-p12.3. The LOX1 protein is synthesized as a 40-kDa precursor protein and is composed of four domains: an extracellular lectin-like domain at the C-terminal, a connecting neck domain, a transmembrane domain, and an N-terminal cytoplasmic domain. Three single nucleotide polymorphism (SNPs), namely, intron 4 (G→A), intron 5(T→G), and 3' UTR (T→C) in the LOX1 gene, have been previously reported. These polymorphisms have also been associated with CAD.

Oxygen is a lifesaving drug. Giving oxygen to a patient with an impending clinical emergency has become knee-jerk reflex reaction of the clinician. Patient with AMI has compromised myocardial perfusion and event arises due to myocardial hypoxia. It appears quite logical and biologically plausible to give oxygen in such situations to improve the oxygenation of the ischemic myocardial tissue and decrease ischemic pain. On the other side, oxygen may be harmful with a mechanism such as the paradoxical effect of oxygen in decreasing coronary artery blood flow and increasing coronary vascular resistance due to increased oxygen free radicals. The investigators aimed to examine the association of the OLR1 gene with AMI or CAD in a novel, well-phenotyped, and homogenous, population and its correlation with oxygen therapy in these patients.