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Cytokines released from activated mono-

Background-In vivo hepatic phosphorus-31 magnetic resonance spectroscopy (MRS) provides non-invasive information about phospholipid metabolism. Aims-To delineate MRS abnormalities in patients with chronic ductopenic rejection (CDR) and to characterise spectral changes by in vitro MRS and electron microscopy. Patients and methods-Sixteen liver transplant recipients (four with CDR; 12 with good graft function) and 29 controls (23 healthy volunteers; six patients with biliary duct strictures) were studied with in vivo 31 P MRS. Peak area ratios of phosphomonoesters (PME) and phosphodiesters (PDE), relative to nucleotide triphosphates (NTP) were measured. In vitro MRS and electron microscopy were performed on biopsy specimens from five patients with CDR, freeze clamped at retransplantation. Phosphoethanolamine (PE), phosphocholine (PC), glycerophosphorylethanolamine (GPE), and glycerophosphorylcholine (GPC) concentrations were measured. Results-The 12 patients with good graft function displayed no spectral abnormalities in vivo; the four patients with CDR showed significantly elevated PME:NTP (p<0.01) and PDE:NTP ratios (p<0.005). Patients with biliary strictures had significant diVerences 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 and PC, mirroring the in vivo changes in PME, but reduced GPE and GPC concentrations were observed, at variance with the in vivo PDE findings. On electron microscopy, there was no proliferation in hepatocyte endoplasmic reticulum. Conclusions-The increase in PME:NTP reflects altered phospholipid metabolism in patients with CDR, while the increase in PDE:NTP may represent a significant contribution from bile phospholipid. (Gut 1998;42:735-743) Keywords: in vivo 31 P magnetic resonance spectroscopy; in vitro 31 P magnetic resonance spectroscopy; liver transplantation; chronic ductopenic rejection; electron microscopy; phospholipids Orthotopic hepatic transplantation has become the treatment of choice for end stage liver failure, but between 2% and 17% of patients subsequently develop chronic graft rejection, occurring most often between six weeks and six months postoperatively.

Acute phase proteins are released from the liver in response to cytokines, and

Extracellular matrix (ECM) in the liver affects the phenotype of both hepatocytes and non-parenchymal cells. To be able to mimic in vivo liver function for extracorporeal hepatic support using human cell lines, a necessary step is to upregulate the function normally seen in monolayer culture. 3-D spheroid colonies were formed by culturing single HepG2 cells encapsulated in alginate beads. ECM expression in these cultures was compared to monolayer Hep G2 cultures. The following ECM proteins were detected immunohistochemically:- collagens 1, III, V and VI, the glycoproteins fibronectin, tenascin and vitronectin, and the basement membrane protein laminin. In 3-D cultures, all proteins except tenascin were strongly expressed, as compared with weak or undetectable expression in monolayer cultures, even with 10-fold increases in the antibody concentration used. In conclusion, we have demonstrated that the 3-D environment created by alginate encapsulation of cell lines leads to cell behaviour mimicking that in vivo.