Adenosine antagonist 8‐SPT decreases rate of microvessel growth in mouse left ventricular angiogenesis assay in vitro

Abstract

Adenosine is thought to play a pivotal role in the regulation of angiogenesis. We tested the hypothesis that an adenosine receptor antagonist, 8‐(p‐Sulfophenyl) theophylline (8‐SPT), can decrease angiogenesis. Two in vitro angiogenesis assays were used: rat aortic ring and mouse left ventricle (LV). Explants were embedded in collagen and incubated in various O2 environments for 14 days. Aortic rings sprouted microvessels (MVs) in serum‐free media (EBM, Lonza) when incubated in room air (peak increase, 80‐90 MVs on days 6‐7): 2% O2 inhibited MV growth on days 4‐10 by 40‐50%, 12% O2 had no effect, and 5% O2 caused a 20‐30% increase in MVs on days 6‐10, compared to room air controls. 8‐SPT (5x10‐5 M; 3x week) had no effect on MV growth in aortic rings incubated in either room air or 5% O2. LV explants sprouted MVs in EBM/10% FBS media when incubated in 2% O2 (peak increase: 237±17, day 8); MVs did not grow in room air. 8‐SPT decreased the rate of angiogenesis in mouse LV from 81±14 MVs/day (control, day 6) to 31±4 MVs/day (8‐SPT, day 6) in cultures incubated in 2% O2. 8‐SPT also decreased (p<0.01) the peak number of MVs from 237±17 (control, day 8) to 161±17 (8‐SPT, day 10). The results support the hypothesis that adenosine plays an important role in mediating hypoxia‐induced angiogenesis in mouse left ventricle, but does not play a role in mediating MV growth in rat aorta in vitro. (Supported by HL‐51971)