PANCREATIC ENDOCRINE CELL NEOGENESIS

在人类胚胎发育过程中， 从胰腺导管中分离出来 同样的发展模式 在其他哺乳动物身上也能看到。 β细胞的丧失 最初的胰腺内分泌细胞群导致胰岛素- 依赖性糖尿病（胰岛素依赖型糖尿病，青少年发病，酮症， 俯卧型，I型），通常通过胰岛素治疗来控制。 治疗I型糖尿病的一种方法可能包括 刺激成人β细胞再生和分化 胰腺组织 虽然内分泌细胞从 胰管可以发生在新生儿，这种发育 这一过程在成年哺乳动物中通常受到抑制。 最近的研究 表明内分泌细胞（α和β）可以被诱导， 在适当的体外条件下， 从成年雄性大鼠分离的胰管。 研究 本申请中提出的建议旨在从结构上 并在功能上表征内分泌细胞新生， 使用该体外模型从胰管分化。 在目前的建议中，研究涉及隔离和文化的 大鼠和人的胰管。 初步实验涉及 大鼠导管，重点是内分泌祖细胞， 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 胰岛素和胰高血糖素遗传探针的杂交，和4） 电镜 后续研究将确定1）如果 大鼠导管的再生内分泌细胞分泌激素， 对促分泌素的反应，以及2）如果内分泌细胞新生 可在成年雄性大鼠体内诱导。 进一步的研究将确定是否在体外新生的 内分泌细胞可以从分离的胰管中诱导 从成人胰腺中分离出来。 期末考试将筛选 各种提议的“诱导物”分子，因为它们能够 在培养的大鼠胰管中刺激这一过程。 虽然 除了这三年赠款提案的范围外， 这项工作的目标是制定程序， 细胞新生可以在I型糖尿病患者中诱导， 他们最初的β细胞数量

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.