Inhibition of protein tyrosine phosphatases enhances cerebral collateral growth in rats.

Arteriogenesis involves the rapid proliferation of preexisting arterioles to fully functional arteries as a compensatory mechanism to overcome circulatory deficits. Stimulation of arteriogenesis has therefore been considered a treatment concept in arterial occlusive disease. Here, we investigated the impact of inhibition of protein tyrosine phosphatases (PTPs) on cerebral arteriogenesis in rats. Arteriogenesis was induced by occlusion of one carotid and both vertebral arteries (three-vessel occlusion (3-VO)). Collateral growth and functional vessel perfusion was assessed 3–35 days following 3-VO. Furthermore, animals underwent 3-VO surgery and were treated with the pan-PTP inhibitor BMOV, the SHP-1 inhibitor sodium stibogluconate (SSG), or the PTP1B inhibitor AS279. Cerebral vessel diameters and cerebrovascular reserve capacity (CVRC) were determined, together with immunohistochemistry analyses and proximity ligation assays (PLA) for determination of tissue proliferation and phosphorylation patterns after 7 days. The most significant changes in vessel diameter increase were present in the ipsilateral posterior cerebral artery (PCA), with proliferative markers (PCNA) being time-dependently increased. The CVRC was lost in the early phase after 3-VO and partially recovered after 21 days. PTP inhibition resulted in a significant increase in the ipsilateral PCA diameter in BMOV-treated animals and rats subjected to PTP1B inhibition. Furthermore, CVRC was significantly elevated in AS279-treated rats compared to control animals, along with hyperphosphorylation of the platelet-derived growth factor-β receptor in the vascular wall in vivo. In summary, our data indicate PTPs as hitherto unrecognized negative regulators in cerebral arteriogenesis. Further, PTP inhibition leading to enhanced collateral growth and blood perfusion suggests PTPs as novel targets in anti-ischemic treatment.