Development of a Serum and Cellular Biomarkers Cluster for the Assessment of Degenerative Aortic Valve Stenosis Progression.

The deposition of calcium salts in the arterial wall and the heart valves is a commonly occurring phenomenon associated with increasing age and various pathological factors. A particular case is the calcification of the aortic valve, which is accompanied by gradual stenosis leading to heart failure. As a result, causes significant morbidity and a dramatic increase in mortality if not treated surgically or via transcatheter intervention. It affects approximately 2% of the population over the age of 65, being the third cause of death in this population. It numbers about 100 surgeries per 100,000 person-years in the decade and 180000 patients each year are candidates for percutaneous aortic valve implantation (TAVI) in the US, Canada, and European Union.

Characteristic of the disease is that it remains even today without a diagnosis at the critical early stages and all existing therapies have failed to slow or reverse the damage when applied in the final stages. Previous experimental studies suggested that existing drugs may be more effective if given early in the disease course. At the time when the aortic stenosis becomes evident on echocardiography or Computerized Tomography (CT), underlying biochemical and molecular lesions have already developed. Moreover, among the aortic valve stenosis patients, it is unknown who will rapidly evolve to a dynamic narrowing of the valve and previous research studies report significantly diverse progression rates among patients, with approximately 20-25% demonstrating more than double rates. Thus, the Achilles heel of the therapeutic management of patients is the lack of early diagnosis and disease progression prognosis.

Under a combination of pathological effects by factors such as hypertension, diabetes mellitus and dyslipidemia in patients with a possible genetic predisposition, impairment of the normal structure and function of endothelium occurs, which progressively leads to the disease of the underlying valve tissue. Local acidosis and accumulation of oxidative oxygen radicals cause damage to membrane phospholipids, oxidation of cholesterol and proteins, which lose their normal quaternary structure and degrade. The gradual deposition of phosphate and calcium carbonate salts over the pathological proteins leads to calcification of the valve tissue. Intense inflammatory reaction with activation of bone marrow and infiltration of tissue with immunocompetent cells accompanies the damage: macrophages, B and T lymphocytes, mast cells infiltrate and actively contribute to the disease. Within this environment, inflammatory cytokines secreted from the inflammatory cells lead to activation of embryonic cell pathways that help to further enhance the calcification through the conversion of resident fibroblasts to active osteoblasts, which actively deposit calcium salts through extracellular vesicles.

In the disease, multiple cell types and distant organs are involved (liver - cholesterol metabolism, spleen and bone marrow - immune response activation) and the damage is expected to release fragments of biological and biochemical substances in the blood circulation. Hence, the disease is expected to be reflected in changes in serum protein. It is possible to detect proteins and metabolites in the blood serum in appropriately selected patients, prospectively enrolled and monitored through the course of aortic valve stenosis. An optimal subgroup description of patients with rapid or slow disease progression can reveal important information for future clinical diagnostic and prognostic use. Moreover, the disease is characterized by cellular infiltration of a plethora of known and unknown immune cells that contribute to the disease. Thus, the discovery of novel cellular phenotypes linked to disease progression can help delineate important clinical aspects.

The purposes of Athena Valve are: