Liposomal ATP protects the liver from injury during shock

Liposomes are useful drug carriers. In this study, adenosine triphosphate (ATP) was entrapped in liposomes (Lip-ATP). Anesthetized rats were given Lip-ATP (5 mg/kg as ATP), free ATP (5 mg/kg) or saline (control group) during stabilization. Then, the rats were exposed to 30 min of hypovolemic shock and 30 min of reperfusion. Administration of Lip-ATP significantly improved hepatic blood flow during shock (13.2 +/- 1.7 ml/min/100 g tissue in the Lip-ATP group vs. 9.4 +/- 2.2, in the control group, and 8.9 +/- 2.9 in the free ATP group) and during reperfusion (20.9 +/- 2.3, 16.3 +/- 2.2, and 16.2 +/- 1.8 ml/min/100 g tissue, respectively). The serum levels of hepatic enzymes (ALT, AST and LDH) were significantly lower in the Lip-ATP group after reperfusion when compared with the control and free ATP groups. Administration of Lip-ATP also produced the best recovery of hepatic ATP level. These findings indicate that Lip-ATP increased hepatic blood flow during shock and reperfusion, presumably by improving the energy charge and metabolism of the hepatocytes. Thus, Lip-ATP appears to be a useful agent for liver injury induced by hypovolemic shock.