The validity of the MEGX test in correlation with histology after orthotopic rat liver transplantation.

Abstract

Lidocaine metabolism (MEGX test) as an indicator for liver function in the assessment of different degrees of liver disease and as a predictor for liver outcome after transplantation is well established. Since reduced liver function is associated with an alteration in parenchymal and non-parenchymal cells, we evaluated whether MEGX values correlate with histology in an in vivo model of orthotopic rat liver transplantation (ORLT) to assess histological damage without taking biopsy specimens. Livers from syngeneic Lewis rats were transplanted with rearterialization after 15-30 h of cold storage in UW solution and rinsing with Carolina Rinse Solution prior to implantation. Forty-eight hours after transplantation, the MEGX test was performed and metabolites were measured with a commercial kit as described elsewhere. Biopsy specimens were taken and graded three degrees of damage (mild, moderate, and severe) in a double blind fashion by a pathologist. MEGX values were assigned to the histological results. Statistical analyses were done with a Mann-Whitney test (n = 58) for mean values. The mean MEGX values attributed to histologies with a mild, moderate, severe degree of damage were 159.96, 78.46 and 44.42 ng/ml, respectively. When the histological groups were compared with the mean MEGX values, mild vs moderate, mild vs severe and moderate vs severe were significant (P - 0.0001). In conclusion, MEGX values correlate significantly with histological grading in a linear fashion after ORLT. The MEGX test may be of clinical value because it reflects the histological pattern of livers and may reduce the necessity to take biopsy specimens before and after transplantation.