IN-VIVO AND IN-VITRO HEPATIC P-31 MAGNETIC-RESONANCE SPECTROSCOPY ANDELECTRON-MICROSCOPY IN CHRONIC DUCTOPENIC REJECTION OF HUMAN LIVER ALLOGRAFTS

Background-In vivo hepatic phosphorus-31 magnetic resonance spectrosco py (MRS) provides non-invasive information about phospholipid metaboli sm. Aims-To delineate MRS abnormalities in patients with chronic ducto penic rejection (CDR) and to characterise spectral changes by in vitro MRS and electron microscopy. Patients and methods-Sixteen liver trans plant recipients (four with CDR; 12 with good graft function) and 29 c ontrols (23 healthy volunteers; six patients with biliary duct strictu res) were studied with in vivo P-31 MRS Peak area ratios of phosphomon oesters (PME) and phosphodiesters (PDE), relative to nucleotide tripho sphates (NTP) were measured. In vitro MRS and electron microscopy were performed on biopsy specimens from five patients with CDR, freeze cla mped at retransplantation. Phosphoethanolamine (PE), phosphocholine (P C), glycerophosphorylethanolamine (GPE), and glycerophosphorylcholine (GPC) concentrations were measured. Results-The 12 patients with good graft function displayed no spectral abnormalities in vivo; the four p atients with CDR showed significantly elevated PME:NTP (p<0.01) and PD E:NTP ratios (p<0.005). Patients with biliary strictures had significa nt differences in PME:NTP (p<0.01) from patients with CDR, but not in mean PDE:NTP. In vitro spectra from CDR patients showed elevated PE an d PC, mirroring the in vivo changes in PME, but reduced GPE and GPC co ncentrations were observed, at variance with the in vivo PDE findings. On electron microscopy, there was no proliferation in hepatocyte endo plasmic reticulum. Conclusions-The increase in PME:NTP reflects altere d phospholipid metabolism in patients with CDR, while the increase in PDE:NTP may represent a significant contribution from bile phospholipi d.