第二型糖尿病患有非常高的風險會因心血管疾病而死亡，在糖尿病常見的眾多因子中，定義糖尿病的高血糖，扮演一個重要的角色。高血糖會透過許多機制造成血管的併發症，例如: 形成糖化終產物 (advanced glycation end products)，增加氧化壓力，這些都會造成動脈粥狀硬化。過去許多研究集中在動脈硬化過程中，各種細胞激素和成長因子及其牽動的細胞的變化。然而,是否高血糖會誘導平滑肌細胞其PDGF(platelet-derived growth factor)表現，並進而促使動脈硬化，仍有待釐清。我們因此研究在高糖環境培養下的巨噬細胞培養液 (High Glucose Macrophage-Conditioned Medium, HG-MCM)，是否會釋放某種因子誘導平滑肌增生。我們發現直接用高糖刺激平滑肌細胞，會誘導其增生；而用HG-MCM刺激血管平滑肌細胞，則會放大增生的效應。進一步探討其中的物質為PDGF-CC，無論使用PDGF-CC (platelet-derived growth factor-CC) 抗體，或是PDGF受體拮抗劑，都可以減弱PDGF-CC 誘導平滑肌增生的能力。這些研究結果顯示，在糖尿病粥狀硬化過程中，PDGF-CC及PDGF受體α和β， 都扮演一個重要的病態生理機轉角色。

Patients with type 2 diabetes mellitus are at risk of death from cardiovascular causes. Among the multipl risk facotors in patient with diabetes, hyperglycemia, which defines the diabetic state, plays an important role. Hyperglycemia can promote vascular complications by multiple mechanisms, with formation of advanced glycation end products and increased oxidative stress, proposed to contribute to atherosclerosis. Several studies have examined the expression of the various cytokines and growth factors that may be involved in the cellular changes that accompany developing lesions. However, whether high glucose could induce the PDGF (platelet-derived growth factor) expression in vascular smooth muscle cells (VSMCs) and in turns contribute to the development of atherosclerosis remains to be determined. We investigated the mechanism underlying the modulation of SMC proliferation in atherosclerosis by high-glucose treated macrophage-conditioned medium (MCM). We found that SMC proliferation can be induced by direct glucose stimulation and which was further augmented by high glucose-MCM. Pre-treatment of SMC with PDFG-R (platelet-derived growth factor-receptor receptor) anti-body block the proliferative effect of MCM. Pre-treatment of MCM with PDFG-C anti-body also diminish the proliferation of SMC. Our present data suggested that in the development of atherosclerosis in diabetes, PDGF-R and PDGF-C might be an important factor involved in the patho-physiological responses to high glucose in human VSMCs.

Chapter I Introduction
1.1 Diabetes mellitus and cardiovascular disease……………………. 1
1.2 Pathogenesis of atherosclerosis in diabetes………………………. 1
1.3 Role of VSMC in atherosclerosis………………………………... .3
1.4 Induction of inflammatory cytoines in macrophage under high glucose concentration…………………………………………….. 4
1.5 PDGF and atherosclerosis…………………………………………5
1.6 Cyclin-Dependent Kinase Inhibitors p27Kip1, p21Cip1, and
Vascular Smooth Muscle Cell Proliferation……………………...6
Chapter II Materials and Methods……………………………………8
2.1 Cell Cultures………………………………………………………9
2.2 Human monocyte isolation………………………………………..9
2.3 Preparation of human MCM……………………………………..10
2.4 Western Blot Analysis……………………………………………10
2.5 MTT assay and flow cytometric analysis for cell proliferarion.....10
Chapter III Results…………………………………………………..12
3.1 SMC proliferation induced by high glucose treatment…………..13
III
3.2 Glucose could promote SMC growth and its effect
further magnified by high glucose treated macrophage-conditioned medium (HG-MCM)………………..13
3.3 The stimulation of SMC proliferation by HG-MCM is in a concentration-dependent manner……………………………….13
3.4 Enhance proliferation of SMC by HG-MCM but not by
NG-MCM……………………………………………………….14
3.5 PDGF-CC in HG-MCM is major mediators for the induction of SMC proliferation………………………………………………14
3.6 HG-MCM induced SMC proliferation is mediated by PDGF
receptor α and PDGF receptor β………………………………..15
3.7 PI3K-p70S6K pathway is required for HG-MCM induced SMC proliferation……………………………………………………..16
3.8 HG-MCM decreased the expression of cyclin-dependent kinase inhibitors p21Cip1 and p27Kip …………………………………..17
Chapter IV　Discussion………………………………………………..18
Chapter V Reference………………………………………………….23
Figures and Tables……………………………………………………..31

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