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ABSTRACT Endothelial dysfunction/apoptosis is critical to the development of neointima hyperplasia. Our pilot study identified a novel member of the caspase subfamily, caspase 13 (CASP 13), which is induced by oxidized low density lipoprotein (ox-LDL) in endothelial cells, but not in vascular smooth muscle cells. It remains controversial whether CASP 13 is a human or bovine gene. In this study, we collected four human brachial artery segments during arterioveinous fistula graft removal surgeries. By western blot and quantitative RT-PCR analysis, CASP13 expression was elevated at the anastomosis of brachial arteries from patients receiving hemodialysis. Rat carotid artery balloon model is widely used as in vivo atherosclerosis model for studies on neointima formation and especially vascular smooth muscle proliferation. However, most of the balloon injury studies terminated on the 14th day to sacrifice the animals for histological studies. In this study, we employed the ultrasonic device to record the hemodynamic changes in rat carotid artery at different time intervals after balloon injury. The pre-operative mean left carotid artery internal diameter and blood flow of Sprauge Dawley rats was 0.6 ¡Ó 0.07 mm and 28.75 ¡Ó 4.45 cm/sec, respectively. After balloon dilatation, the mean internal diameter of left carotid artery elevated to 0.77 ¡Ó 0.09 mm and 0.71 ¡Ó 0.08 mm on day 7 and day 14, respectively. Besides, the mean blood flow velocity also increased to 47.6 ¡Ó 9.2 cm/sec and 33.4 ¡Ó 10.8 cm/sec on day 7 and day 14, respectively. However, the left carotid artery blood flow velocity returned to 24 ¡Ó 3.5 cm/sec on day 21. The CASP 13 protein expression was found elevated in the balloon injury sites and mainly localized in the endothelial cells. In summary, CASP 13 is detected in endothelial cells in both human and rat atherosclerosis models and may constitute a novel molecular target for vascular diseases.

Texte remanié de: Diss.--Universiteit van Amsterdam, 2000. / Bibliogr. p. 313-324.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 132-156). Also available on the World Wide Web.

Thesis (Ph. D.)--Case Western Reserve University, 2004. / [School of Medicine] Department of Pathology. Includes bibliographical references. Available online via OhioLINK's ETD Center.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 109-112). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 109-112). Also available on the Internet.

Chronic rejection is a major obstacle to long-term survival of organ transplants. PPAR-γ agonist rosiglitazone has been shown to reduce graft rejection but the underlying mechanisms remain unclear. Combined treatment of rosiglitazone and anti-IL-5 antibody prevented MHC class II histoincompatiblecardiac graft rejection with a reduction of cellular infiltration, vasculopathy and interstitial fibrosis in a heterotopic heart transplantation model. In particularly, rosiglitazone decreased CD8 T cells infiltration and luminal occlusion, while anti-IL-5 antibody reduced eosinophil infiltration and collagen deposition. Adiponectin gene (APN) is a PPAR-γ target gene, and the expression of APN receptor AdipoRII in grafts, dendritic cells (DCs) and T cells are increased by rosiglitazone. These findings prompted me to further examine the immunomodulatory role of APN in graft rejection. APN is an anti-inflammatory adipocytokine, and has been shown to inhibitimmunostimulatory function of monocytes and macrophages. Rosiglitazone suppresses DCs maturation, activation and proliferation;hence, it is possible that APN could protect graft rejection through immunoregulation of DCs. Here, using in vitro culture systems, I found that APN has only moderate effect on the differentiation of bone marrow derived DCs but itcould alter DC phenotypes. APN-treated DCs showed an increased expression of PD-L1, which is consistent with the increased PD-L1 expression in rosiglitazone treated cardiac allografts. APN-treated DCs led to a decreased proliferation and reduction of IL-2production of T cell. Moreover, APN-treated DCs increased the expansion of Tregs (regulatory T cells) which could be inhibited by the blockage of PD-1/PD-L1 pathway, suggesting that PD-1/PD-L1 pathway and expansion of Tregs played important roles in APN-treated DCs mediated immunomodulation. Further, I employed APN-/-mice for functional and mechanistic studies, and found that cardiac allografts were not rejected by APN-/-recipient mice even after 120 days post-transplantation. Histological analyses revealed very little eosinophils, CD4 and CD8 T cells infiltration; no collagen deposit and no vessel occlusion in the cardiac allografts. Furthermore, Th2 cytokines such as IL-4 and IL-5 were lower in cardiac allografts and in the serum of APN-/-recipient. Inhibition of AMPK signaling, a major APN mediated pathway, reduced the eosinophils infiltration in wild type recipient. In contrast, AMPK activation increased eosinophils infiltration in APN-null recipient. APN enhanced T cell proliferation. AMPK and P38MAPK inhibitors as well as anti-IL-4 antibody inhibited APN-induced T cell proliferation. P38 MAPK inhibitors reduced IL-4 production in mature DCs but enhanced IL-4 expression in immature DCs. In EL-4 T cells, APN increased nuclear expressions of GATA-3 and p-STAT6 and augmented IL-4 expression, and the phenomenon was suppressed by target specific knockdown of AdipoR I and II. In summary, current study provides new mechanistic insights of PPAR-γ activation and APN signaling in the modulation of adaptive and transplantation immunity, establishing a link between metabolism and immune regulation. / published_or_final_version / Surgery / Doctoral / Doctor of Philosophy