Z Gastroenterol 2013; 51 - P_3_33
DOI: 10.1055/s-0032-1332028

Bile: miRNA pattern and cell morphology as a diagnostic tool after liver transplantation

RB Schmuck 1, N Raschzok 1, A Reutzel-Selke 1, S Lippert 1, S König 1, KA Prabowo 1, MH Morgul 2, LM Tannus 1, S Jonas 2, P Neuhaus 1, IM Sauer 1
  • 1Charité – Universitätsmedizin Berlin, General, Visceral, and Transplantation Surgery, Experimental Surgery and Regenerative Medicine, Berlin, Germany
  • 2Universitätsklinikum Leipzig, Department of Visceral, Transplantation, Thoracic, and Vascular Surgery, Leipzig, Germany

Aim: The international gold standard to detect acute rejection after liver transplantation (LTx) is liver biopsy, a procedure with considerable risks for the patient. Acute rejection is an immune response which causes inflammation and can mimic cholangitis, making the discrimination of those two disease challenging.

In search for less invasive diagnostic tools, bile as a direct synthesis product of the transplanted liver may be analyzed in patients with external bile drain. microRNAs (miRNAs) are emerging as biomarkers for diagnosis and prediction of transplant rejection. The aim of our investigation was to study the changes in morphology of cholangular epithelial cells as well as to investigate miRNAs expression in the bile of LTx recipients and to evaluate its usability as a diagnostic tool after liver transplantation.

Material and Methods:

Patients (n=19) undergoing LTx with external bile drain were included in a prospective clinical study. Bile samples were collected at consecutive time points after LTx (postoperative days 1, 3, 5, 7) and when clinical signs of rejection were observed. We analyzed the level of the miRNAs 122, 194, 133a and 148a in bile samples and normalized the expression to total RNA. In addition, we performed light microscopy after hematoxyline and eosine staining. Bile samples of n=10 Patients with acute rejection and n=9 controls were used for PCR analysis.

Results: Isolation of sufficient amounts of RNA from bile as well as histochemical staining was possible and results were evaluable. miR-122, miR-194, and miR-148a were significantly up-regulated in the bile of patients with an episode of acute rejection, out of which miR-194 showed the strongest upregulation. MiR-133a was also upregulated, but the results were not significant. Compared to the controls, cholangiocytes in samples of patients with an episode of acute rejection showed vacuolization as well as unrounding and segmentation of the cell nucleus. The cytoplasma-nucleus ratio changed towards the nucleus.

Conclusions: miRNA pattern and cell morphology in bile in immediate postoperative follow up after liver transplantation may serve as a practicable tool to optimize diagnostics.