Treprostinil Improves Hepatic Cytochrome P450 Activity during Rat Liver Transplantation

Hepatic ischemia-reperfusion syndrome and its effect on the cardiovascular system: The role of treprostinil, a synthetic prostacyclin analog

Hepatic ischemia-reperfusion syndrome has been the subject of intensive study and experimentation in recent decades since it is responsible for the outcome of several clinical entities, such as major hepatic resections and liver transplantation. In addition to the organ's post reperfusion injury, this syndrome appears to play a central role in the dysfunction of distant tissues and systems. Thus, continuous research should be directed toward finding effective therapeutic options to improve the outcome and reduce the postoperative morbidity and mortality rates. Treprostinil is a synthetic analog of prostaglandin I2, and its experimental administration has shown encouraging results. It has already been approved by the Food and Drug Administration in the United States for pulmonary arterial hypertension and has been used in liver transplantation, where preliminary encouraging results showed its safety and feasibility by using continuous intravenous administration at a dose of 5 ng/kg/min. Treprostinil improves renal and hepatic function, diminishes hepatic oxidative stress and lipid peroxidation, reduces hepatictoll-like receptor 9 and inflammation, inhibits hepatic apoptosis and restores hepatic adenosine triphosphate (ATP) levels and ATP synthases, which is necessary for functional maintenance of mitochondria. Treprostinil exhibits vasodilatory properties and antiplatelet activity and regulates proinflammatory cytokines; therefore, it can potentially minimize ischemia-reperfusion injury. Additionally, it may have beneficial effects on cardiovascular parameters, and much current research interest is concentrated on this compound.

Treprostinil alleviates hepatic mitochondrial injury during rat renal ischemia-reperfusion injury

BACKGROUND

Renal ischemia-reperfusion injury (IRI) causes acute kidney injury as well as liver injury. Renal IRI depletes hepatic antioxidants, promotes hepatic inflammation and dysfunction through Tlr9 upregulation. There is no treatment available for liver injury during renal IRI. This study examines the hepatoprotective role of treprostinil, a prostacyclin analog, during renal IRI.

METHODS

Male Sprague-Dawley rats were divided into four groups: control, sham, IRI-placebo, or IRI-treprostinil and subjected to bilateral ischemia (45 min) followed by reperfusion (1-72 h). Placebo or treprostinil (100 ng/kg/min) was administered subcutaneously via an osmotic minipump.

RESULTS

Treprostinil significantly reduced peak serum creatinine, BUN, ALT and AST levels vs. IRI-placebo. Treprostinil also restored hepatic levels of superoxide dismutase, glutathione, catalase, and Gclc expression to baseline, while reducing lipid peroxidation vs. IRI-placebo. Additionally, treprostinil significantly reduced elevated hepatic Tlr9, Il-1β, Ccl2, Vcam1, and Serpine1 mRNA expression. Renal IRI increased hepatic apoptosis which was inhibited by treprostinil through reduced cytochrome c and cleaved caspase-3 protein expression. Treprostinil enhanced hepatic ATP concentrations and mitochondrial DNA copy number and improved mitochondrial dynamics by restoring Pgc-1α expression and significantly upregulating Mfn1, Mfn2, and Sirt3 levels, while reducing Drp-1 protein vs. IRI-placebo. Non-targeted semi-quantitative proteomics showed improved oxidative stress indices and ATP subunits in the IRI-treprostinil group.

CONCLUSIONS

Treprostinil improved hepatic function and antioxidant levels, while suppressing the inflammatory response and alleviating Tlr9-mediated apoptotic injury during renal IRI. Our study provides evidence of treprostinil's hepatoprotective effect, which supports the therapeutic potential of treprostinil in reducing hepatic injury during renal IRI.

Hepatic Cytochrome P450 Profiles in Hemorrhagic Shock Model Rats After Transfusion With Stored Red Blood Cells

Red cell transfusions, which deteriorate in quality during storage, triggers several negative biological responses. However, little is known regarding the effects of stored red cell transfusion on cytochrome P450 (P450) profiles. To clarify this issue, we investigated hepatic P450 profiles in hemorrhagic shock model rats after resuscitation with stored packed red cells (PRC). The pharmacokinetics data for P450-metabolizing substrates showed that the clearance of substrates for Cyp1A2 and Cyp3A2 in the stored PRC resuscitation group were decreased compared to sham group. The protein expression, metabolic activity and mRNA expression of the P450 isoforms in the stored PRC resuscitation group were lower than the corresponding values for the sham group. However, these changes would be expected to have weak effects on the in vivo pharmacokinetics of the concomitant drugs based on the criteria stated in the guideline on drug interactions. In contrast, the results of these P450 profiles in the stored PRC and fresh PRC resuscitation group exhibited a similar trend. These results suggest that the stored PRC transfusion has an influence on the hepatic P450 profiles, but is of little clinical significance, not by the deterioration of the quality of red cells but pathophysiological alterations following the hemorrhage and transfusion.