Nucleotide ecto-enzyme metabolic pattern and spatial distribution in calcific aortic valve disease; its relation to pathological changes and clinical presentation

Abstract

Background Extracellular nucleotide metabolism contributes to chronic inflammation, cell differentiation, and tissue mineralization by controlling nucleotide and adenosine concentrations and hence its purinergic effects. This study investigated location-specific changes of extracellular nucleotide metabolism in aortic valves of patients with calcific aortic valve disease (CAVD). Individual ecto-enzymes and adenosine receptors involved were analyzed together with correlation with CAVD severity and risk factors. Results Nucleotide and adenosine degradation rates were adversely modified on the aortic surface of stenotic valve as compared to ventricular side, including decreased ATP removal (1.25 ± 0.35 vs. 2.24 ± 0.61 nmol/min/cm 2 ) and adenosine production (1.32 ± 0.12 vs. 2.49 ± 0.28 nmol/min/cm 2 ) as well as increased adenosine deamination (1.28 ± 0.31 vs. 0.67 ± 0.11 nmol/min/cm 2 ). The rates of nucleotide to adenosine conversions were lower, while adenosine deamination was higher on the aortic sides of stenotic vs. non-stenotic valve. There were no differences in extracellular nucleotide metabolism between aortic and ventricular sides of non-stenotic valves. Furthermore, nucleotide degradation rates, measured on aortic side in CAVD (n = 62), negatively correlated with echocardiographic and biochemical parameters of disease severity (aortic jet velocity vs. ATP hydrolysis: r = − 0.30, p < 0.05; vs. AMP hydrolysis: r = − 0.44, p < 0.001; valvular phosphate concentration vs. ATP hydrolysis: r = − 0.26, p < 0.05; vs. AMP hydrolysis: r = − 0.25, p = 0.05) while adenosine deamination showed positive correlation trend with valvular phosphate deposits (r = 0.23, p = 0.07). Nucleotide and adenosine conversion rates also correlated with CAVD risk factors, including hyperlipidemia (AMP hydrolysis vs. serum LDL cholesterol: r = − 0.28, p = 0.05; adenosine deamination vs. total cholesterol: r = 0.25, p = 0.05; LDL cholesterol: r = 0.28, p < 0.05; triglycerides: r = 0.32, p < 0.05), hypertension (adenosine deamination vs. systolic blood pressure: r = 0.28, p < 0.05) and thrombosis (ATP

Extracellular Nucleotides Regulate Arterial Calcification by Activating Both Independent and Dependent Purinergic Receptor Signaling Pathways

“…In line with these results, activation of the A 2A receptor promoted the mineralization process in VIC cultures by favoring the cAMP/protein kinase A pathway, while activation of the A 1 receptor resulting in decreased cAMP levels, inhibited VIC mineralization [31]. Moreover, adenosine treatment of mice aortic roots exposed to an osteogenic medium attenuated mineralization by A 1 and A 2B receptor activation, whereas the A 2A receptor had an opposite effect on aortic root mineralization [74]. Recently, an in vitro study using human aortic smooth muscle cells demonstrated that triggering the A 3 receptor resulted in a reduction in matrix mineralization, probably by decreasing alkaline phosphatase activity [75].…”

Therapeutic Perspectives of Adenosine Deaminase Inhibition in Cardiovascular Diseases

“…In other study, Sajjan et al showed a significant positive correlation between enhanced serum ADA levels and increase in systolic (SBP) and diastolic blood pressure (DBP) in subjects with metabolic syndrome [ 112 ]. Also our results revealed a strong positive correlation of tissue eADA activity estimated in calcified aortic valves with SBP and DBP in patients with calcified aortic valve disease [ 24 ]. There is no data elucidating the origin of elevated ADA activity in hypertension.…”

“…Each AR has unique cell and tissue distribution, secondary signaling transductors, affinity for adenosine, and physiological effects. In cardiovascular system, all AR subtypes were demonstrated in endothelium, vascular smooth muscle cells, cardiomyocytes, valve cells and many others [ 4 , 22 , 24 ]. A 1 R and A 3 R predominantly activate heterotrimeric G proteins belonging to the Gα i/o family, which inhibit cAMP production by adenylate cyclase, in contrast A 2A R and A 2B R predominantly activate Gαs family members, which stimulate cAMP production [ 25 ].…”

The new insight into extracellular NAD+ degradation‐the contribution of CD38 and CD73 in calcific aortic valve disease

“…Aortic valves were stained using haematoxylin/eosin (HE) and Masson's trichrome (TR) staining, as well as the previously published Orcein Martius Scarlet Blue (OMSB) protocol, to distinguish collagen, elastic lamina and smooth muscle cells and visualize atherosclerotic plaques in valves obtained from CAVD patients 22 . To distribute and localize CD38, CD73, eNPP1 and ALP protein, we used immunohistochemistry and antibody conjugated to a fluorophore (immunofluorescence) in human non‐stenotic (n = 4) and stenotic aortic valves (n = 3) as described previously 23 . Briefly, fragments of tissue were completely embedded in the OCT compound, frozen in −80°C and then cut by a cryostat.…”