PANCREATIC ENDOCRINE CELL NEOGENESIS

在人类胚胎发育过程中，朗格汉斯的胰岛发育 来自胰腺小管。同样的发展模式是 在其他哺乳动物身上也有发现。由此造成的β细胞的损失 最初的胰腺内分泌细胞群导致胰岛素- 依赖型糖尿病(IDDM、青少年发病、酮症-- 俯卧位，I型)，通常通过胰岛素治疗进行治疗。 治疗I型糖尿病的一种方法可能包括 促进成人β细胞再生和分化的实验研究 胰腺组织。尽管内分泌细胞从 胰管可以出现在新生儿身上，这是一种发育 在成年哺乳动物中，这一过程通常被抑制。最新研究 表明内分泌细胞(α和β)可以被诱导成 在适当的体外条件下分化为 分离成年雄性大鼠的胰管。这些研究 在这项赠款申请中提出的建议在结构上旨在 并在功能上表征内分泌细胞新生和 使用这个体外模型来区分胰管。 在本提案中，研究涉及隔离和培养 大鼠和人的胰管。最初的实验包括 大鼠导管，重点放在内分泌祖细胞上 在导管上皮内。这些研究将描述 胰岛形成的初始阶段使用1) 放射自显影，2)免疫细胞化学，3)原位 胰岛素和胰升糖素基因探针的杂交，以及4) 电子显微镜。以后的研究将确定1)是否 大鼠导管再生的内分泌细胞分泌激素 对促分泌剂的反应，以及2)如果内分泌细胞新生 在成年雄性大鼠体内可诱导出胰管来源。 更多的研究将确定是否在体外新生 分离的胰管可诱导出内分泌细胞 取自成人胰腺。期末研究将筛选出 各种被提议的“诱导剂”分子的能力 在培养的大鼠胰管中刺激这一过程。虽然 除了这项为期三年的拨款计划的范围外，长期 这项工作的目标是开发内分泌的程序 在I型糖尿病患者中可以诱导细胞新生 它们最初的β细胞种群。

During human embryogenesis, the Islets of Langerhans develop from pancreatic ductules. This same developmental pattern is seen in other mammals as well. Loss of beta cells from this initial pancreatic endocrine cell population leads to insulin- dependent diabetes mellitus (IDDM, juvenile-onset, Ketosis- prone, Type I) which is normally managed by insulin treatment. One approach to the treatment of Type I diabetes could involve stimulation of beta cell regeneration and differentiation in adult pancreatic tissue. Although endocrine cell differentiation from pancreatic ducts can occur in the neonate, this developmental process is normally surpressed in adult mammals. Recent studies indicate that endocrine cells (alpha and beta) can be induced to differentiate under the appropriate in vitro conditions from pancreatic ducts isolated from adult male rats. The studies proposed in this grant application are designed to structurally and functionally characterize endocrine cell neogenesis and differentiation from pancreatic ducts using this in vitro model. In the present proposal, studies involve isolation and culture of rat and human pancreatic ducts. Initial experiments involving rat ducts, focus on the endocrine progenitor cells which reside within the ductal epithelium. These studies will characterize the initial stages in the formation of pancreatic islets using 1) autoradiography, 2) immunocytochemistry, 3) in situ hybridization of insulin and glucagon genetic probes, and 4) electron microscopy. Later studies will determine 1) if regenerated endocrine cells of rat ducts discharge hormones in response to secretagogues, and 2) if endocrine cell neogenesis from pancreatic ducts can be induced in vivo in adult male rats. Additional studies will determine if in vitro neogenesis of endocrine cells can be induced from pancreatic ducts isolated from the adult human pancreas. Final studies will screen a variety of proposed "inducer" molecules for their ability to stimulate this process in cultured rat pancreatic ducts. Although beyond the scope of this three-year grant proposal, the long term goal of this work is to develop procedures by which endocrine cell neogenesis can be induced in Type I diabetics who have lost their initial beta-cell population.