TIMP-3 ameliorates hepatic ischemia/reperfusion injury through inhibition of tumor necrosis factor-alpha-converting enzyme activity in rats.
BACKGROUND
Tumor necrosis factor (TNF)-alpha and its receptors play a critical role in the inflammatory cascade after hepatic ischemia/reperfusion injury. TNF-alpha converting enzyme (TACE) or disintegrin and metalloproteinase (ADAM)-17 is a metalloproteinase disintegrin that specifically cleaves precursor TNF-alpha to its mature form and is involved in the ectodomain shedding of TNF receptors. The regulation of TACE is poorly understood and its role in liver injury and/or regeneration is unknown.


METHODS
Male Wistar rats were subjected to 10 or 30 min of partial warm hepatic ischemia followed by 3 to 24 hr of reperfusion. Serum and/or hepatic TACE, TNF-alpha, TNF receptor 1 (TNFR1), and interleukin (IL)-6 levels were assessed by enzyme-linked immunosorbent assay, real-time reverse-transcriptase polymerase chain reaction, and/or Western blot.


RESULTS
Low levels of TACE were detected in normal liver tissue. Both 10 and 30 min warm ischemia resulted in a rise in TACE expression which peaked six hr after reperfusion. TNF-alpha, TNFR1, and IL-6 levels were up-regulated in a pattern similar to TACE messenger RNA (mRNA) levels. Moreover, selective inhibition of TACE activity by specific inhibitor tissue inhibitor of metalloproteinase (TIMP)-3 at dosages of 100 or 1000 ng/kg body weight showed significant decrease of circulating TNF-alpha and serum alanine transferase (ALT) levels and histological improvement of hepatic ischemia/reperfusion injuries.


CONCLUSIONS
TACE expression and its activity, as measured by increases in TNF-alpha, TNFR1, and IL-6 levels, are increased following hepatic ischemia/reperfusion injury, implying that TACE plays an important role in hepatic ischemia/reperfusion injury. Amelioration of hepatic ischemia/reperfusion injury after inhibition of TACE activity by TIMP-3 suggests that TACE inhibition may play an important role in preventing liver ischemia/reperfusion injury warranting further experimental and clinical study.
Tang
Zhen-Ya
ZY
Transplantation Research Laboratory, Ochsner Clinic Foundation, New Orleans, LA 70121, USA.
Loss
George
G
Carmody
Ian
I
Cohen
Ari J
AJ
D051722:ADAM Proteins / Q000037:antagonists & inhibitors*; D000072198:ADAM17 Protein; D000818:Animals; D006801:Humans; D015850:Interleukin-6 / Q000032:analysis / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000032:analysis / Q000378:metabolism; D015427:Reperfusion Injury / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control*; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000494:pharmacology* / Q000627:therapeutic use; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000378:metabolism
D015850:Interleukin-6; D047888:Receptors, Tumor Necrosis Factor, Type I; D019717:Tissue Inhibitor of Metalloproteinase-3; C506237:Tnfrsf1a protein, rat; D014409:Tumor Necrosis Factor-alpha; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human; C000606464:Adam17 protein, rat