Evaluation of pancreatic endocrine and exocrine function in patients with autoimmune pancreatitis.
OBJECTIVE
Up to now, the characteristics of pancreatic endocrine and exocrine functions in autoimmune pancreatitis (AIP) are still unclear. The aim of this study is to evaluate pancreatic functions in AIP compared with those of chronic pancreatitis (CP).


METHODS
Twelve patients with AIP and 25 patients with CP were examined for exocrine and endocrine pancreas. Exocrine function was evaluated by a secretin test. Concerning endocrine function, insulin secretion (C-peptide response) was examined with the glucagon tolerance test and glucagon secretion was examined with the arginine tolerance test. Pathological examination of pancreatic tissues was done on the operative specimens of AIP and CP that could not be clinically excluded from pancreatic cancer.


RESULTS
For the secretin test, 8.3% of patients with AIP showed 1-factor abnormality, which was a reduction in volume, and 41.7% showed 2-factor abnormalities, which were a reduction in volume and amylase output. On the other hand, 44.0% of patients with CP showed only 1-factor abnormality, which was the reduction in the maximum bicarbonate concentration. Autoimmune pancreatitis accompanied with diabetes mellitus showed a reduction both in DeltaC-peptide response (beta-cell response) and Deltaglucagon (alpha-cell response). Histologically, AIP showed lymphoplasmatic cells infiltration surrounding the pancreatic ducts, but basement membranes were intact. Moreover, basement membranes of the duct were injured in CP. Furthermore, islet cells in AIP were revealed as almost intact even though they were surrounded by fibrosis.


CONCLUSIONS
These findings indicate that exocrine dysfunction with AIP is different from CP because AIP induces stenosis of the pancreatic ducts, but ductal cells that possess the function of bicarbonate secretion are intact, and that endocrine dysfunction with AIP was secondary pancreatic diabetes.
Ito
Tetsuhide
T
Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. itopapa@intmed3.med.kyushu-u.ac.jp
Kawabe
Ken
K
Arita
Yoshiyuki
Y
Hisano
Terumasa
T
Igarashi
Hisato
H
Funakoshi
Akihiro
A
Sumii
Toshihiko
T
Yamanaka
Takeharu
T
Takayanagi
Ryoichi
R
D000328:Adult; D000368:Aged; D001327:Autoimmune Diseases / Q000473:pathology / Q000503:physiopathology*; D001639:Bicarbonates / Q000378:metabolism; D003251:Constriction, Pathologic; D003920:Diabetes Mellitus / Q000473:pathology / Q000503:physiopathology; D005260:Female; D005355:Fibrosis; D005934:Glucagon / Q000378:metabolism; D018149:Glucose Intolerance / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D046790:Pancreas, Exocrine / Q000378:metabolism / Q000473:pathology / Q000502:physiology*; D010183:Pancreatic Ducts / Q000473:pathology / Q000502:physiology; D050500:Pancreatitis, Chronic / Q000276:immunology / Q000473:pathology / Q000503:physiopathology*; D012633:Secretin / Q000378:metabolism
D001639:Bicarbonates; D007328:Insulin; D012633:Secretin; D005934:Glucagon