Emerging Role of IGF-1R in Stretch-Induced Neointimal Hyperplasia in Venous Grafts

Vessels cultured ex vivo maintain viability and vasoactivity for weeks and can remodel in response to mechanical cues. When cultured in the presence of 5% CO2/balance air veins develop neointimal hyperplasia (IH) while arteries do not suggesting that exposure to significant increases in pO2 levels might stimulate IH. Neointimal hyperplasia (IH) is a known mechanism by which saphenous veins have a decreased patency compared to arterial conduits when used for coronary artery bypass. We sought to explore the role of oxygen tension and oxidative stress in IH. Test the hypothesis that exposure of human saphenous veins (HSV) to arterial pO2 stimulates IH via ROS-mediated pathways. Almost 40 HSV remnants acquired following CABG were cultured ex vivo with arterial (~95mmHg) pO2 or venous (~40mmHg) pO2 for 14 days. All differences reported have a p<0.05 via Student’s t-test. Results: HSV cultured at arterial pO2 exhibited significant IH as evidenced by disruption of the IEL, invasion of cells from the media, and a 2.8-fold greater intimal area than fresh HSV, a 5.8-fold increase in cell proliferation compared to fresh HSV, increased ROS levels and oxidative stress as evidenced by 4-fold increase in 4-HNE level (a marker of oxidative stress), increased DHE staining (indicative of superoxide generation), and a progressive increase in total ROS levels with time as assessed by DCF fluorescence, and a 3-fold increase in phosphorylated p38-MAPK, which is implicated in SMC proliferation. In stark contrast vessels culture at arterial pO2, HSV cultured with venous pO2 did not develop increased IH and were indistinguishable from fresh vessels with respect to proliferation, markers of oxidative stress, and MAPK expression levels. Supplementing culture medium with antioxidants including Tiron or NAC blocked the pO2-induced changes. These data indicate that exposure to arterial pO2 increases cellular proliferation and stimulates IH, potentially via oxidative stress or ROS signaling and also suggest that exposure to elevated arterial pO2 might stimulate pathological remodeling of veins grafted into the arterial circulation. This research has received full or partial funding support from the American Heart Association, AHA Great Rivers Affiliate (Delaware, Kentucky, Ohio, Pennsylvania & West Virginia).

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Role of Venous Grafts in Combination with Arterial Grafting

Arterial Grafting for Coronary Artery Bypass Surgery ◽

10.1007/3-540-30084-8_38 ◽

2006 ◽

pp. 291-297

Author(s):

G. -W. He

Keyword(s):

Venous Grafts ◽

Arterial Grafting

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Reduced Expression of Glutathione S-Transferase α4 Promotes Vascular Neointimal Hyperplasia in CKD

Journal of the American Society of Nephrology ◽

10.1681/asn.2017030290 ◽

2017 ◽

Vol 29 (2) ◽

pp. 505-517 ◽

Cited By ~ 2

Author(s):

Jinlong Luo ◽

Guang Chen ◽

Ming Liang ◽

Aini Xie ◽

Qingtian Li ◽

...

Keyword(s):

Glutathione Transferase ◽

Neointimal Hyperplasia ◽

Critical Role ◽

Mapk Signaling ◽

Neointima Formation ◽

Glutathione S Transferase ◽

Protein Levels ◽

Underlying Mechanisms ◽

Arteries And Veins

Neointima formation is the leading cause of arteriovenous fistula (AVF) failure. We have shown that CKD accelerates this process by transforming the vascular smooth muscle cells (SMCs) lining the AVF from a contractile to the synthetic phenotype. However, the underlying mechanisms affecting this transformation are not clear. Previous studies have shown that the α-class glutathione transferase isozymes have an important role in regulating 4-hydroxynonenal (4-HNE)–mediated proliferative signaling of cells. Here, using both the loss- and gain-of-function approaches, we investigated the role of glutathione S-transferase α4 (GSTA4) in modulating cellular 4-HNE levels for the transformation and proliferation of SMCs. Compared with non-CKD controls, mice with CKD had downregulated expression of GSTA4 at the mRNA and protein levels, with concomitant increase in 4-HNE in arteries and veins. This effect was associated with upregulated phosphorylation of MAPK signaling pathway proteins in proliferating SMCs. Overexpressing GSTA4 blocked 4-HNE–induced SMC proliferation. Additionally, inhibitors of MAPK signaling inhibited the 4-HNE–induced responses. Compared with wild-type mice, mice lacking GSTA4 exhibited increased CKD-induced neointima formation in AVF. Transient expression of an activated form of GSTA4, achieved using a combined Tet-On/Cre induction system in mice, lowered levels of 4-HNE and reduced the proliferation of SMCs. Together, these results demonstrate the critical role of GSTA4 in blocking CKD-induced neointima formation and AVF failure.

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1P-0205 Functional analysis about the role of Smad3-dependent transforming growth factor-β signaling in neointimal hyperplasia

Atherosclerosis Supplements ◽

10.1016/s1567-5688(03)90276-5 ◽

2003 ◽

Vol 4 (2) ◽

pp. 64-65

Author(s):

K. Kobayashi ◽

K. Yokote ◽

Y. Maezawa ◽

H. Kawamura ◽

M. Fujimoto ◽

...

Keyword(s):

Functional Analysis ◽

Growth Factor ◽

Transforming Growth Factor ◽

Neointimal Hyperplasia ◽

Transforming Growth Factor Β

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Perivascular Delivery of Rapamycin in Pluronic Gel Inhibits Neointimal Hyperplasia in a Rat Carotid Artery Injury Model, and the Complementary Role of Carotid Arteriography

Korean Circulation Journal ◽

10.4070/kcj.2008.38.2.80 ◽

2008 ◽

Vol 38 (2) ◽

pp. 80 ◽

Cited By ~ 3

Author(s):

Mi-Jin Jung ◽

Jin-Sook Kwon ◽

No-Kwan Park ◽

Yu-Kyung Kim ◽

Tae Jin Shim ◽

...

Keyword(s):

Carotid Artery ◽

Neointimal Hyperplasia ◽

Carotid Artery Injury ◽

Artery Injury ◽

Complementary Role ◽

Injury Model

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Activation of heme oxygenase-1 by Ginkgo biloba extract differentially modulates endothelial and smooth muscle-like progenitor cells for vascular repair

Scientific Reports ◽

10.1038/s41598-019-53818-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Tao-Cheng Wu ◽

Jia-Shiong Chen ◽

Chao-Hung Wang ◽

Po-Hsun Huang ◽

Feng-Yen Lin ◽

...

Keyword(s):

Bone Marrow ◽

Smooth Muscle ◽

Progenitor Cells ◽

Heme Oxygenase ◽

Neointimal Hyperplasia ◽

Vascular Repair ◽

Vascular Progenitor Cells

AbstractVascular progenitors such as endothelial progenitor cells (EPCs) and smooth muscle-like progenitor cells (SMPCs) may play different roles in vascular repair. Ginkgo biloba extract (GBE) is an exogenous activator of heme oxygenase (HO)-1, which has been suggested to improve vascular repair; however, the detailed mechanisms have yet to be elucidated. This study aimed to investigate whether GBE can modulate different vascular progenitor cells by activating HO-1 for vascular repair. A bone marrow transplantation mouse model was used to evaluate the in vivo effects of GBE treatment on wire-injury induced neointimal hyperplasia, which is representative of impaired vascular repair. On day 14 of GBE treatment, the mice were subjected to wire injury of the femoral artery to identify vascular reendothelialization. Compared to the mice without treatment, neointimal hyperplasia was reduced in the mice that received GBE treatment for 28 days in a dose-dependent manner. Furthermore, GBE treatment increased bone marrow-derived EPCs, accelerated endothelial recovery, and reduced the number of SMPCs attached to vascular injury sites. The effects of GBE treatment on neointimal hyperplasia could be abolished by co-treatment with zinc protoporphyrin IX, an HO-1 inhibitor, suggesting the in vivo role of HO-1. In this in vitro study, treatment with GBE activated human early and late EPCs and suppressed SMPC migration. These effects were abolished by HO-1 siRNA and an HO-1 inhibitor. Furthermore, GBE induced the expression of HO-1 by activating PI3K/Akt/eNOS signaling in human late EPCs and via p38 pathways in SMPCs, suggesting that GBE can induce HO-1 in vitro through different molecular mechanisms in different vascular progenitor cells. Accordingly, GBE could activate early and late EPCs, suppress the migration of SMPCs, and improve in vivo vascular repair after mechanical injury by activating HO-1, suggesting the potential role of pharmacological HO-1 activators, such as GBE, for vascular protection in atherosclerotic diseases.

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