Minimal portal vein stenosis is a promising preconditioning in living donor liver transplantation in porcine model

Surgical Models of Liver Regeneration in Pigs: A Practical Review of the Literature for Researchers

The remarkable capacity of regeneration of the liver is well known, although the involved mechanisms are far from being understood. Furthermore, limits concerning the residual functional mass of the liver remain critical in both fields of hepatic resection and transplantation. The aim of the present study was to review the surgical experiments regarding liver regeneration in pigs to promote experimental methodological standardization. The Pubmed, Medline, Scopus, and Cochrane Library databases were searched. Studies evaluating liver regeneration through surgical experiments performed on pigs were included. A total of 139 titles were screened, and 41 articles were included in the study, with 689 pigs in total. A total of 29 studies (71% of all) had a survival design, with an average study duration of 13 days. Overall, 36 studies (88%) considered partial hepatectomy, of which four were an associating liver partition and portal vein ligation for staged hepatectomy (ALPPS). Remnant liver volume ranged from 10% to 60%. Only 2 studies considered a hepatotoxic pre-treatment, while 25 studies evaluated additional liver procedures, such as stem cell application, ischemia/reperfusion injury, portal vein modulation, liver scaffold application, bio-artificial, and pharmacological liver treatment. Only nine authors analysed how cytokines and growth factors changed in response to liver resection. The most used imaging system to evaluate liver volume was CT-scan volumetry, even if performed only by nine authors. The pig represents one of the best animal models for the study of liver regeneration. However, it remains a mostly unexplored field due to the lack of experiments reproducing the chronic pathological aspects of the liver and the heterogeneity of existing studies.

Portal vein stenosis preconditioning of living donor liver in swine: early mechanisms of liver regeneration and gain of hepatic functional mass

To reduce the morbidity and mortality risk for the donor in living donor liver transplantation (LDLT), we previously identified 20% left portal vein (LPV) stenosis as an effective preconditioning method to induce cell proliferation in the contralateral lobe without downstream ipsilateral atrophy. In this study, we report the pathways involved in the first hours after preconditioning and investigate the changes in liver volume and function. Fourteen pigs were used this study. Five pigs were used to study the genetic, cellular and molecular mechanisms set up in the early hours following the establishment of our preconditioning. The remaining nine pigs were equally divided into three groups: sham-operated animals, 20% LPV stenosis, and 100% LPV stenosis. Volumetric scanning and 99 mTc-Mebrofenin hepatobiliary scintigraphy were performed before preconditioning and 14 days after to study morphological and functional changes in the liver. We demonstrated that liver regeneration triggered by 20% LPV stenosis in the contralateral lobe involves TNF-α, IL-6, and inducible nitric oxide synthase 2 by means of STAT3 and hepatocyte growth factor. We confirmed that our preconditioning was responsible for an increase in the total liver volume. Finally, we demonstrated that this volumetric gain was associated with an increase in hepatic functional capacity. NEW & NOTEWORTHY We describe a new preconditioning method for major hepatectomy that is applicable to hepatectomy for donation. We identified 20% left portal vein stenosis as effective preconditioning that is capable of inducing cell proliferation in the contralateral lobe without the downstream ipsilateral atrophy. In this study, we report the pathways involved in the first hours following preconditioning, and we confirm that 20% left portal vein stenosis is responsible for an increase in the functional capacity and total liver volume in a porcine model.

In situ splitting after selective partial portal vein ligation or simultaneous hepatic artery ligation promotes liver regeneration

This study seeks to compare the impact of selective partial portal vein ligation (PPVL) or the combination of simultaneous hepatic artery ligation (PPVAL) with in situ splitting (ISS) on liver regeneration and injury. Rats were randomized into three groups; namely: selective PVL, PPVL + ISS and PPVAL + ISS. The changes in hepatic hemodynamics, liver regeneration and hepatocytic injury were examined. Blood flow to the left portal branch and the microcirculation of the left median lobe after PPVL or PPVAL was significantly reduced. Liver regeneration of PPVAL + ISS group was more pronounced than that in the PPVL + ISS and PVL groups at 48 and 72 hours as well as 7 d postoperatively. The serum biochemical markers and histopathological examination demonstrated reduced levels of liver injury in the PPVL + ISS group. Injury to hepatocytes was more pronounced with PPVAL + ISS than PVL. HGF, TNF-α and IL-6 expression in the regenerated lobes in both PPVAL + ISS and PPVL + ISS groups increased significantly when compared to the PVL group. We demonstrated that both PPVL + ISS and PPVAL + ISS were effective and feasible means of inducing remnant liver hypertrophy and could serve as a rapid clinical application for qualified patients.