Tissue Engineering Strategies: Effects on Valvular Interstitial Cell Metabolism

描述(由申请人提供)： 项目摘要首席研究员：凯瑟琳·简·格兰德-艾伦博士。心脏瓣膜疾病要求每年有近10万美国人住院治疗。虽然瓣膜病的一些最初原因已被很好地认识，但中间的细胞介导的疾病机制在很大程度上是未知的。大多数瓣膜疾病的唯一有效治疗方法是手术修复或替换；目前还没有预防或改善瓣膜疾病的药物或治疗方法。剖析潜在的疾病机制和开发新的医学疗法的驱动力刺激了瓣膜生物学的研究。虽然这一领域还处于起步阶段，但已经见证了许多关于瓣膜间质细胞(VICS)的收缩、合成、细胞通讯、黏附和信号特性的最新发现，特别是当它们与瓣膜组织工程和钙化性主动脉瓣疾病的发展有关时。尽管如此，对瓣膜细胞新陈代谢的研究还很少。虽然最近的出版物已经讨论了氧气扩散和灌流如何影响瓣膜细胞和组织工程瓣膜，但瓣膜细胞新陈代谢的主题在很大程度上仍然没有得到解决。正常成人瓣膜内的细胞保持静止(即使在这样一个机械活动的组织中)，但显示出激活并改变其表型/行为的能力，以响应各种损伤或疾病条件。这种激活过程的特征相当糟糕，导致了关于VICS在这些静止和激活条件下的基本代谢率的几个问题。这种代谢率如何受到细胞环境的影响也是未知的，也就是细胞周围的基质和机械或化学刺激的水平。鉴于外源性刺激在组织工程瓣膜开发中的应用，以及这些因素在瓣膜重塑和疾病进展中的作用，这些问题非常重要。事实上，新陈代谢被认为是大多数细胞类型对环境压力的第一反应。为了解决这些问题，本研究建议确定VICS的基本代谢率(目标1)。以下两个目标将检验细胞因子和低氧刺激(目标2)和机械拉伸(目标3)对VICS代谢率和代谢基因表达的影响。这项研究具有重要的意义，因为它将为基础和应激培养条件下VICS的代谢率提供新的基础信息，并将为瓣膜细胞生物学领域建立一个重要的新方向。由此产生的数据将补充其他研究人员检查VIC和瓣膜叶的氧气消耗的工作，并将指导科学家和工程师开发组织工程瓣膜。这项工作还将促进瓣膜疾病研究的新途径，因为瓣膜细胞的反应(由新陈代谢实现)可能有助于疾病的进展，无论最初的原因是心脏扩张、感染还是先天性畸形。有关脂肪酸代谢的信息将与钙化性主动脉瓣疾病的早期阶段相关，因为在肥胖、糖尿病和代谢综合征的背景下，这种情况的发生率越来越高。 公共卫生相关性： 公共卫生相关首席研究员：凯瑟琳·简·格兰德-艾伦博士。心脏瓣膜疾病每年导致近10万美国人住院，但心脏瓣膜疾病的原因是一个谜，特别是因为心脏瓣膜细胞的许多行为以前从未被研究过。这项研究将研究心脏瓣膜细胞的新陈代谢，即它们如何利用糖、脂肪酸和乳酸为其活动创造燃料，如迁移和制造新的蛋白质。这项研究还将研究用于制造组织工程心脏瓣膜的几种条件如何影响这种新陈代谢。这项研究也是相关的，因为在肥胖、糖尿病和代谢综合征的背景下，主动脉瓣疾病的发病率不断上升。

DESCRIPTION (provided by applicant): PROJECT SUMMARY Principal Investigator: Kathryn Jane Grande-Allen, Ph.D. Heart valve disease mandates hospitalization for almost 100,000 Americans every year. Although some of the initial causes of valve disease are well recognized, the intermediate cell-mediated disease mechanisms are largely unknown. The only effective treatment for most valve diseases is surgical repair or replacement; there are no medical or therapeutic treatments for the prevention or amelioration of valve disease. The drive to dissect potential disease mechanisms and develop new medical therapies has invigorated research in valve biology. This field is in its infancy, but has nonetheless has witnessed many recent findings about contractile, synthetic, cell communication, adhesion, and signaling characteristics of valvular interstitial cells (VICs), especially as they relate to the tissue engineering of valves and the development of calcific aortic valve disease. Nonetheless, there has been scant investigation into the metabolism of valve cells. Although recent publications have addressed how oxygen diffusion and perfusion affects valve cells and tissue engineered valves, the topic of valvular cell metabolism remains largely unaddressed. Cells within normal adult valves maintain quiescence (even within such a mechanically active tissue), but show the capacity to become activated and alter their phenotype/behavior in response to various injury or disease conditions. This activation process is quite poorly characterized, leading to several questions about the fundamental metabolic rates of VICs under these quiescent and activated conditions. It is also unknown how this metabolic rate is influenced by the environment of the cell, meaning its pericellular matrix and level of mechanical or chemical stimulation. These issues are very important given the use of exogenous stimuli in the development of tissue engineered valves, and the roles of these factors in valve remodeling and disease progression. Indeed, metabolism is recognized as the first responder to environmental stresses for most cell types. To address these questions, this research proposes to determine the fundamental metabolic rates of VICs (Aim 1). The following 2 aims will examine the effect of cytokine and hypoxic stimulation (Aim 2) and mechanical stretch (Aim 3) on metabolic rates and metabolic gene expression by VICs. This research is significant because it will provide new and fundamental information about the metabolic rates of VICs under basal and stressed culture conditions, and will establish an important new direction in the field of valve cell biology. The resulting data will complement the work of other investigators examining oxygen consumption of VICs and valve leaflets, and will guide scientists and engineers developing tissue engineered valves. This work will also promote new avenues for valve disease research, since the valve cell responses (enabled by metabolism) likely contribute to disease progression, whether the initial cause was cardiac dilatation, infection, or a congenital malformation. Information about fatty acid metabolism would be relevant to the early stages of calcific aortic valve disease, since there is a growing incidence of this condition in the setting of obesity, diabetes, and metabolic syndrome. PUBLIC HEALTH RELEVANCE: Public Health Relevance Principal Investigator: Kathryn Jane Grande-Allen, Ph.D. Heart valve disease leads to hospitalization for almost 100,000 Americans every year, but the causes of heart valve disease are a mystery, especially because much of the behavior of heart valve cells has never been previously studied. This research will study the metabolism of heart valve cells, meaning how they use sugars, fatty acids, and lactate to create fuel for their activities such as migrating and making new proteins. This research will also examine how several conditions that are used to create tissue engineered heart valves affect this metabolism. This research is also relevant due to the growing incidence of aortic valve disease in the setting of obesity, diabetes, and metabolic syndrome.