Development of the endocrine pancreas and novel strategies for beta-cell mass restoration and diabetes therapy

Diabetes mellitus represents a serious public health problem owing to its global prevalence in the last decade. The causes of this metabolic disease include dysfunction and/or insufficient number of β cells. Existing diabetes mellitus treatments do not reverse or control the disease. Therefore, β-cell mass restoration might be a promising treatment. Several restoration approaches have been developed: inducing the proliferation of remaining insulin-producing cells, de novo islet formation from pancreatic progenitor cells (neogenesis), and converting non-β cells within the pancreas to β cells (transdifferentiation) are the most direct, simple, and least invasive ways to increase β-cell mass. However, their clinical significance is yet to be determined. Hypothetically, β cells or islet transplantation methods might be curative strategies for diabetes mellitus; however, the scarcity of donors limits the clinical application of these approaches. Thus, alternative cell sources for β-cell replacement could include embryonic stem cells, induced pluripotent stem cells, and mesenchymal stem cells. However, most differentiated cells obtained using these techniques are functionally immature and show poor glucose-stimulated insulin secretion compared with native β cells. Currently, their clinical use is still hampered by ethical issues and the risk of tumor development post transplantation. In this review, we briefly summarize the current knowledge of mouse pancreas organogenesis, morphogenesis, and maturation, including the molecular mechanisms involved. We then discuss two possible approaches of β-cell mass restoration for diabetes mellitus therapy: β-cell regeneration and β-cell replacement. We critically analyze each strategy with respect to the accessibility of the cells, potential risk to patients, and possible clinical outcomes.

Recent developments in purinergic receptors of endocrine pancreas / 中国药理学通报

Purinergic receptors are divided into P1(adenosine)and P2(ATP)receptors.P2 receptor are divided into two subtypes,namely P2X(ligand-gated ion channels)and P2Y(G-protein coupled)receptors.Several kinds of purinoceptor subtypes have been expressed in endocrine pancreas and participate in regulating the secretion of insulin.Purinoceptor and ligand are correlated with pathogenesis of diabetes mellitus and complications and make it possible to provide a new target to treat diabetes mellitus and complications.

Endocrine Tumors of the Pancreas Secreting Multiple Hormones / 대한내분비학회지

BACKGROUND: Endocrine pancreas tumor is a rare disease which incidence is less than 2% of all pancreatic tumors. But it comprises various types of tumor and usually secretes several hormones from one type of tumor although the patient with this tumor complains of sole symptom associated with only one hormone. The mechanism and clinical significance of multiple hormone secretion in the endocrine pancreas tumom are not yet clearly defined. METHODS: We analyzed retrospectively the clinicopathologic features of 20 cases which were operated at Seoul National University Hospital during the period between February 1989 and May 1998. RESULTS: The most common tumor was insulinoma (13 cases) and the second most common tumor was nonfunctioning tumor (6 cases). There was one case of somatostatinoma. Most of the patients with insulinoma complained of neuroglycopenic symptoms. There were 9 cases (45.0%) in which the tumors secreted more than two kinds of hormones, 7 cases in insulinoma, 2 cases in nonfunctioning tumors. Whether the tumor secreted multiple hormones was detected by the method of immunohistochemical staining. Though the tumors secreted more than two kinds of hormones, the patients with the tumors complained of symptoms which were associated with the cell type most strongly stained by immunohistochemical method. Whether or not the tumors secreted multiple hormones was not associated with the pathologic features such as tumor size, histologic patterns of the tumor, status of tumor cell differentiation and malignancy. CONCLUSION: From this results, we suggest that endocrine tumors of the pancreas secreted multiple hormones not by the mechanism of dedifferentiation from already differentiated endocrine cells but by the mechanism of neogenesis of multipotent islet stem cells. Since the relationship between the function of multiple hormone secretion in the endocrine pancreas tumors and islet stem cell would be significant, further study should be needed to find out the function of stem cells and application of stem cells to clinical use.