NONINVASIVE ASSESSMENT OF ATP REGENERATION POTENTIAL OF THE PRESERVEDDONOR LIVER - A P-31 MRS STUDY IN PIG-LIVER

We have developed a quick, non-invasive method for measuring the abili ty of an isolated preserved liver to regenerate high energy phosphate nucleotides without the need for biopsy. Using P-31 MRS we have monito red the hepatic energetics of intact cold preserved pig liver using st andard clinical harvesting and storage techniques. Following cold stor age for 2 h the livers were hypothermically reperfused with oxygenated modified University of Wisconsin preservation fluid. Prior to reperfu sion MRS detectable adenosine diphosphate plus adenosine triphosphate was negligible; however, the spectrum showed intense resonances from p hosphomonoesters and inorganic phosphate, as a consequence of adenosin e triphosphate hydrolysis during cold preservation. Following a 10-min period of hypothermic reperfusion, regeneration of adenosine triphosp hate occurred with a concurrent decline in inorganic phosphate and pho sphomonoester, both of which are associated with adenosine triphosphat e synthesis. The capacity of the liver to regenerate adenosine triphos phate following a 24-h period of cold storage was reduced by approxima tely 40% (p<0.01) of the total amount achieved following the shorter c old storage time. Adenosine triphosphate regenera tion rates were biph asic and were decreased upon prolonged storage, with the initial rate being reduced from 40.6 . 10(-2). min(-1) (standard deviation (sd) 2.7 0 . 10(-2). min(-1)) to 14.8 . 10(-2). min(-1) (sd; 2.4 . 10(-2). min( -1)) and the secondary rate from 1.77 . 10(-2). min(-1) (sd; 0.18 . 10 (-2). min(-1)) to 0.84 . 10(-2). min(-1) (sd; 0.45 . 10(-2). min(-1)). MR images of the liver during the period of hypothermic reperfusion w ere also performed providing an assessment for the degree of hepatic v ascular perfusion. This non-invasive, P-31 MRS assessment of hepatic e nergetics in a clinically relevant animal model has great potential fo r the understanding of graft preservation injury.