Pathophysiology of Coronary Artery Disease

Association of Thymidylate Synthase (TS) Gene Polymorphisms with Incidence and Prognosis of Coronary Artery Disease

Coronary artery disease (CAD) is a prevalent cardiovascular condition characterized by the accumulation of plaque within coronary arteries. While distinct features of CAD have been reported, the association between genetic factors and CAD in terms of biomarkers was insufficient. This study aimed to investigate the connection between genetic factors and CAD, focusing on the thymidylate synthase (TS) gene, a gene involved in DNA synthesis and one-carbon metabolism. TS plays a critical role in maintaining the deoxythymidine monophosphate (dTMP) pool, which is essential for DNA replication and repair. Therefore, our research targeted single nucleotide polymorphisms that could potentially impact TS gene expression and lead to dysfunction. Our findings strongly associate the TS 1100T>C and 1170A>G genotypes with CAD susceptibility. We observed that TS 1100T>C polymorphisms increased disease susceptibility in several groups, while the TS 1170A>G polymorphism displayed a decreasing trend for disease risk when interacting with clinical factors. Furthermore, our results demonstrate the potential contribution of the TS 1100/1170 haplotypes to disease susceptibility, indicating a synergistic interaction with clinical factors in disease occurrence. Based on these findings, we propose that polymorphisms in the TS gene had the possibility of clinically useful biomarkers for the prevention, prognosis, and management of CAD in the Korean population.

Lipid Management and the Elderly

Advancing age is an independent risk factor for the development of coronary heart disease. However, the significance of hypercholesterolemia as a cardiovascular risk factor in the elderly, has been widely debated. While no large-scale, randomized clinical trial has been conducted to evaluate cholesterol lowering solely in the elderly, evidence from older subgroups in several intervention trials supports the efficacy of lowering elevated low-density lipoprotein cholesterol for reducing cardiovascular risk in the elderly. Furthermore, although the relative risk of hyper-cholesterolemia for coronary heart disease incidence may be attenuated with advancing age, the population-wide impact of treating elevated cholesterol levels in the elderly would be large, due to the high frequency of coronary heart disease in the elderly. This article reviews key issues in the management of hyper-cholesterolemia with respect to coronary heart disease risk reduction in the elderly.

New and emerging theories of cardiovascular disease: infection and elevated iron

Heart disease is the leading cause of death in both men and women in industrialized countries. Despite the tremendous gains made in decreasing the number of deaths due to cardiovascular disease, it still is health care's greatest challenge. Traditional risk factors account for only 50% of the incidence of cardiac disease. In fact, many individuals who develop heart disease have normal cholesterol and blood pressure levels. This suggests that other less well-studied risk factors may also play a role. The purpose of this report is to examine the role that recently suggested risk factors may play in the development of heart disease: coronary artery infection, specifically from Chlamydia pneumoniae, and elevated iron levels. Both initiate an inflammatory response, which might explain the elevated C-reactive protein levels frequently found in those who suffer from cardiac disease.

Stress, inflammation and cardiovascular disease

Various psychosocial factors have been implicated in the etiology and pathogenesis of certain cardiovascular diseases such as atherosclerosis, now considered to be the result of a chronic inflammatory process. In this article, we review the evidence that repeated episodes of acute psychological stress, or chronic psychologic stress, may induce a chronic inflammatory process culminating in atherosclerosis. These inflammatory events, caused by stress, may account for the approximately 40% of atherosclerotic patients with no other known risk factors. Stress, by activating the sympathetic nervous system, the hypothalamic-pituitary axis, and the renin-angiotensin system, causes the release of various stress hormones such as catecholamines, corticosteroids, glucagon, growth hormone, and renin, and elevated levels of homocysteine, which induce a heightened state of cardiovascular activity, injured endothelium, and induction of adhesion molecules on endothelial cells to which recruited inflammatory cells adhere and translocate to the arterial wall. An acute phase response (APR), similar to that associated with inflammation, is also engendered, which is characterized by macrophage activation, the production of cytokines, other inflammatory mediators, acute phase proteins (APPs), and mast cell activation, all of which promote the inflammatory process. Stress also induces an atherosclerotic lipid profile with oxidation of lipids and, if chronic, a hypercoagulable state that may result in arterial thromboses. Shedding of adhesion molecules and the appearance of cytokines, and APPs in the blood are early indicators of a stress-induced APR, may appear in the blood of asymptomatic people, and be predictors of future cardiovascular disease. The inflammatory response is contained within the stress response, which evolved later and is adaptive in that an animal may be better able to react to an organism introduced during combat. The argument is made that humans reacting to stressors, which are not life-threatening but are "perceived" as such, mount similar stress/inflammatory responses in the arteries, and which, if repetitive or chronic, may culminate in atherosclerosis.