Monitoring calcific aortic valve disease: the role of biomarkers.

Calcific aortic valve disease is a common disease in the elderly associated with significant morbidity and mortality. It was once described as a passive degenerative process during which serum calcium attaches to the valve surface and binds to the leaflet. However, during the last decade mounting evidence demonstrated that this disease has an active biologic process with numerous signaling pathways. The histological hallmarks seem to be inflammation, oxidized lipids-also detectable in aortic valve lesions-and a remodeling of the extracellular matrix leading to bone formation. Over the years, growing evidence has indicated the risk factors for calcific aortic stenosis including lipids, hypertension, male gender, renal failure, and diabetes. Additional monitoring tools, such as molecular imaging, could improve risk stratification, while assessment of severity and prognosis of patients with chronic aortic regurgitation, is desirable. Also, several studies have investigated the role of biomarkers regarding their utility in the screening of calcific aortic valve disease and their putative clinical value, though their role still remains undetermined.

Circulating endothelial progenitor cells as biomarkers for prediction of cardiovascular outcomes.

Experimental studies suggest that bone marrow-derived endothelial progenitor cells (EPCs) play an important role in the maintenance of endothelial integrity and hemostasis. The number of circulating EPC has been shown to be inversely correlated with cardiovascular risk factors and vascular function and to predict cardiovascular events independent of both traditional and non-traditional risk factors. Thus, EPCs provide a clinical advantage over the use of other biomarkers as their measurement is directly associated with endothelial function, and available evidence suggests that they are consistently and significantly associated with a spectrum of cardiovascular complications, such as acute coronary syndromes and coronary artery disease. However, many issues in the field of EPC isolation and identification, particularly in regards to the effective and unequivocal molecular characterization of these cells still remain unresolved. In addition, simple EPC counts do not adequately describe cardiovascular disease risk. This limitation is attributable to variation in the definition of EPCs, the number of existing cardiovascular risk factors in different patients as well as a difference in the interaction between EPCs and other hematopoietic progenitor, inflammatory cells or platelets.