Islet formation and regeneration.
OBJECTIVE
To explore the mechanisms of differentiation and development of pancreatic endocrine cells as well as pancreatic regeneration.


METHODS
Human embryonic pancreatic tissue at 7-14 weeks of gestation was collected. Diabetes mellitus rat model was induced with 65 mg/kg of streptozotocin. Insulin, glucagon, somatostatin, nestin, and cytokeratin 19 (CK19) of pancreatic tissues were observed by immunohistochemistry.


RESULTS
At 9 weeks of gestation, pancreatic epithelial cells began to co-express insulin, glucagon, somatostatin, and CK19 before migration. Islet cells gradually congregated along with the increase of aging, and at 14 weeks of gestation histological examination showed islet formation. At 12 weeks of gestation, nestin-positive cells could be seen in the pancreatic mesenchyme. During early embryogenesis, islet cells of pancreatic ducts co-expressed insulin, glucagon, and somatostatin. During pancreatic regeneration after damage, nestin expression of islet cells increased.


CONCLUSIONS
In the early stage of embryogenesis, islet cells of primary pancreatic ducts can be differentiated to multipotential endocrine cells before migration. During tissue regeneration, pancreatic stem cells may differentiate and proliferate to form pancreatic islet.
Yang
Kai-ming
KM
Department of Anatomy, West China Center of Medical Sciences, Sichuan University, Chengdu 610041.
Li
Ai-dong
AD
Mei
Yan
Y
Zhou
Hong-ying
HY
Li
Hua
H
Yang
Hui-jun
HJ
D000818:Animals; D002454:Cell Differentiation; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology; D047108:Embryonic Development / Q000502:physiology*; D004847:Epithelial Cells / Q000166:cytology / Q000502:physiology; D006801:Humans; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000502:physiology; D007515:Islets of Langerhans / Q000166:cytology* / Q000502:physiology; D008297:Male; D010179:Pancreas / Q000166:cytology / Q000196:embryology / Q000502:physiology*; D010183:Pancreatic Ducts / Q000166:cytology / Q000196:embryology / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012038:Regeneration / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism / Q000502:physiology