| 1. |
- Hytönen, Jarkko, et al.
(author)
-
Activation of Peroxisome Proliferator-Activated Receptor-δ as Novel Therapeutic Strategy to Prevent In-Stent Restenosis and Stent Thrombosis
- 2016
-
In: Arteriosclerosis, Thrombosis and Vascular Biology. - 1079-5642 .- 1524-4636. ; 36:8, s. 1534-1548
-
Journal article (peer-reviewed)abstract
- Objective Drug-eluting coronary stents reduce restenosis rate and late lumen loss compared with bare-metal stents; however, drug-eluting coronary stents may delay vascular healing and increase late stent thrombosis. The peroxisome proliferator-activated receptor-delta (PPAR) exhibits actions that could favorably influence outcomes after drug-eluting coronary stents placement. Approach and Results Here, we report that PPAR ligand-coated stents strongly reduce the development of neointima and luminal narrowing in a rabbit model of experimental atherosclerosis. Inhibition of inflammatory gene expression and vascular smooth muscle cell (VSMC) proliferation and migration, prevention of thrombocyte activation and aggregation, and proproliferative effects on endothelial cells were identified as key mechanisms for the prevention of restenosis. Using normal and PPAR-depleted VSMCs, we show that the observed effects of PPAR ligand GW0742 on VSMCs and thrombocytes are PPAR receptor dependent. PPAR ligand treatment induces expression of pyruvate dehydrogenase kinase isozyme 4 and downregulates the glucose transporter 1 in VSMCs, thus impairing the ability of VSMCs to provide the increased energy demands required for growth factor-stimulated proliferation and migration. Conclusions In contrast to commonly used drugs for stent coating, PPAR ligands not only inhibit inflammatory response and proliferation of VSMCs but also prevent thrombocyte activation and support vessel re-endothelialization. Thus, pharmacological PPAR activation could be a promising novel strategy to improve drug-eluting coronary stents outcomes.
|
|
| 2. |
- Vantler, Marius, et al.
(author)
-
Class IA Phosphatidylinositol 3-Kinase Isoform p110 alpha Mediates Vascular Remodeling
- 2015
-
In: Arteriosclerosis, Thrombosis and Vascular Biology. - 1079-5642 .- 1524-4636. ; 35:6, s. 1434-1444
-
Journal article (peer-reviewed)abstract
- Objective-Neointima formation after vascular injury remains a significant problem in clinical cardiology, and current preventive strategies are suboptimal. Phosphatidylinositol 3'-kinase is a central downstream mediator of growth factor signaling, but the role of phosphatidylinositol 3'-kinase isoforms in vascular remodeling remains elusive. We sought to systematically characterize the precise role of catalytic class IA phosphatidylinositol 3'-kinase isoforms (p110 alpha, p110 beta, p110 delta), which signal downstream of receptor tyrosine kinases, for vascular remodeling in vivo. Approach and Results-Western blot analyses revealed that all 3 isoforms are abundantly expressed in smooth muscle cells. To analyze their significance for receptor tyrosine kinases-dependent cellular responses, we used targeted gene knockdown and isoform-specific small molecule inhibitors of p110 alpha (PIK-75), p110 beta (TGX-221), and p110 delta (IC-87114), respectively. We identified p110 alpha to be crucial for receptor tyrosine kinases signaling, thus affecting proliferation, migration, and survival of rat, murine, and human smooth muscle cells, whereas p110 beta and p110 delta activities were dispensable. Surprisingly, p110 delta exerted noncatalytic functions in smooth muscle cell proliferation, but had no effect on migration. Based on these results, we generated a mouse model of smooth muscle cell-specific p110 alpha deficiency (sm-p110 alpha(-/-)). Targeted deletion of p110 alpha in sm-p110 alpha(-/-) mice blunted growth factor-induced cellular responses and abolished neointima formation after balloon injury of the carotid artery in mice. In contrast, p110 delta deficiency did not affect vascular remodeling in vivo. Conclusions-Receptor tyrosine kinases-induced phosphatidylinositol 3'-kinase signaling via the p110 alpha isoform plays a central role for vascular remodeling in vivo. Thus, p110 alpha represents a selective target for the prevention of neointima formation after vascular injury, whereas p110 beta and p110 delta expression and activity do not play a significant role.
|
|
