Mitochondrial dysfunction and apoptosis of acinar cells in chronic pancreatitis.
BACKGROUND
The mechanism of acinar cell death in human chronic pancreatitis (CP) remains largely unexplored. Previous studies have demonstrated the role played by apoptosis and necrosis in experimental pancreatitis; however, their relationship with the progression of CP remains unknown. The present study was carried out to elucidate the role and extent of apoptosis in CP tissues with different histopathological scores and to examine the possible apoptotic pathway involved.


METHODS
Pancreatic tissues (25 CP patients) that had been histopathologically graded (I-III) and ten normal pancreatic tissue samples were evaluated for apoptosis by DNA fragmentation and an in situ TUNEL assay. The expression of various apoptotic and antiapoptotic markers in the tissues were studied by immunohistochemistry and Western blotting. To elucidate the role of the mitochondria in acinar cell death, the mitochondrial membrane potential (DeltaPsim) and ATP levels were determined by flow cytometry and a luminometer.


RESULTS
The presence of DNA fragmentation and apoptotic nuclei in all CP tissues confirmed the presence of apoptosis. The apoptotic index in CP tissue ranged from 0.09% to 0.86% +/- 0.02% and was highest in grade II (0.7 +/- 0.04%) tissues. Differential upregulation of the apoptotic mediators p53, Bax, cytochrome c, and caspase-3 and -9, and downregulation of antiapoptotic Bcl-2, was observed in CP. DeltaPsim on the order of 1.2-to 2.2-fold and ATP depletion in the range of 23%-84% in CP tissues was observed.


CONCLUSIONS
Apoptosis plays an important role both in the initial stages and during the progression of CP, as evident in all tissue grades. Increased DeltaPsim, loss of ATP, and activation of caspases suggests the involvement of intrinsic pathways.
Singh
Lipi
L
Department of General Surgery, Postgraduate Institute of Medical Education and Research, Chandigarh 160 012, India.
Bakshi
Dapinder K
DK
Majumdar
Siddarth
S
Arora
Sunil Kumar
SK
Vasishta
Rakesh Kumar
RK
Wig
Jai Dev
JD
D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D045304:Cytochromes c / Q000378:metabolism; D053938:DNA Fragmentation; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D008297:Male; D053078:Membrane Potential, Mitochondrial; D010179:Pancreas / Q000378:metabolism / Q000473:pathology*; D050500:Pancreatitis, Chronic / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D000255:Adenosine Triphosphate; D045304:Cytochromes c; D020169:Caspases