Circulating soluble cytochrome c in liver disease as a marker of apoptosis.
OBJECTIVE
To measure levels of soluble cytochrome c, a clinical marker of apoptosis in patients with liver disease; determine whether soluble cytochrome c is derived from the liver; and correlate soluble cytochrome c level with histology and disease activity.


METHODS
Laboratory research study with comparison group.


METHODS
Liver Institute, at the Rabin Medical Center, Israel, and In Vitro Toxicology Laboratory, Canada.


METHODS
A total of 108 patients with liver disease and 30 healthy controls.


METHODS
Paired hepatic and portal vein samples were taken via the transjugular vein in patients after liver biopsy and transjugular intrahepatic portacaval shunt, and bile from patients with external biliary drainage. Soluble cytochrome c was measured with an enzyme-linked immunosorbent assay in peripheral blood. Apoptotic cells in liver tissue were identified by morphological criteria and quantitated with the dUTP nick-end-labelling (TUNEL) assay.


METHODS
Soluble cytochrome c level by type of liver disease by clinical and histological findings.


RESULTS
Soluble cytochrome c concentration (mean 187.1 +/- 219.5 ng x mL(-1)) was significantly higher in patients with liver disease than in controls (39.8 +/- 35.1 ng x mL(-1); P = 0.0001), with highest levels in the primary sclerosing cholangitis group (mean 1041.0 +/- 2844.8 ng x mL(-1); P = 0.001). Cytochrome c levels were correlated with serum bilirubin, alkaline phosphatase, creatinine levels, necroinflammatory score and apoptotic index, but not with serum alanine aminotransferase and synthetic liver function tests. In the 16 paired samples, soluble cytochrome c level was higher in the hepatic (mean 267.9 +/- 297.0 ng x mL(-1)) than the portal vein (mean 169.2 +/- 143.3 ng x mL(-1)), and it was highly detectable in bile (mean 2288.0 +/-4596.0 ng x mL(-1)) (P = 0.001). Untreated patients with chronic viral hepatitis (B and C) had significantly higher levels (mean 282.8 +/-304.3 ng x mL(-1)) than treated patients (77.9 +/- 35.8 ng x mL(-1); P = 0.001).


CONCLUSIONS
Soluble cytochrome c levels are increased in different types of liver disease. Soluble cytochrome c is probably derived from the liver and secreted into the bile. Levels correlate with the apoptotic index and are affected by antiviral treatment. Soluble cytochrome c may serve as a serum marker of apoptosis.
Ben-Ari
Z
Z
Liver Institute and Department of Medicine D, Beilinson Campus, Rabin Medical Center, Petah Tiqva, Israel. gbenari@bezeqint.net
Schmilovotz-Weiss
H
H
Belinki
A
A
Pappo
O
O
Sulkes
J
J
Neuman
M G
MG
Kaganovsky
E
E
Kfir
B
B
Tur-Kaspa
R
R
Klein
T
T
D000328:Adult; D017209:Apoptosis / Q000502:physiology*; D001646:Bile / Q000378:metabolism; D015415:Biomarkers / Q000097:blood; D003574:Cytochrome c Group / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006503:Hepatic Veins / Q000378:metabolism; D006509:Hepatitis B / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology; D006526:Hepatitis C / Q000097:blood / Q000188:drug therapy / Q000503:physiopathology; D006801:Humans; D020287:In Situ Nick-End Labeling / Q000379:methods; D008107:Liver Diseases / Q000097:blood* / Q000188:drug therapy / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011169:Portal Vein / Q000378:metabolism; D012995:Solubility
D015415:Biomarkers; D003574:Cytochrome c Group