Gene Expression in the Liver Remnant Is Significantly Affected by the Size of Partial Hepatectomy: An Experimental Rat Study

Effects of agomelatine on rat liver regeneration following partial hepatectomy

Primary or metastatic hepatic malignancies are common. Partial hepatectomy (PH) is the primary treatment for both benign and malignant hepatic neoplasms; it also is used for living donor liver transplantation. The regenerative potential of the liver after PH is 70-80% in humans. We investigated the protective and therapeutic effects of agomelatine (AGM) on rat liver regeneration following PH. We used 32 rats distributed equally into four groups: group 1, sham control; group 2, PH group; group 3, administered 20 mg/kg AGM orally once/day for 7 days following PH; group 4, administered 20 mg/kg AGM orally once/day 3 days before and 7 days following PH for 10 days. Liver samples were analyzed for antioxidants and free radicals. Tissue samples were processed and stained with hematoxylin and eosin to assess histopathological status and stained immunohistochemically for Ki-67. We found that PH reduced antioxidant enzymes and increased tissue reactive oxygen species, whereas AGM treatment had the opposite effect on these parameters. Our biochemical and histopathological findings were consistent. PH caused sinusoid congestion and dilation. Intensity of Ki-67 immunostaining of hepatocytes was increased in group 2, whereas these were reduced in group 4. Intensity of Ki-67 immunostaining of hepatocytes was increased in group 2, whereas it was reduced in the group 4 compared to group 1. We found that AGM was hepatoprotective following PH due to its antioxidant and free radical scavenger properties.

CRISPR/Cas9-mediated metabolic pathway reprogramming in a novel humanized rat model ameliorates primary hyperoxaluria type 1

Primary hyperoxaluria type I is caused by mutations in the alanine glyoxylate aminotransferase gene (AGXT), leading to accumulation of glyoxylate and subsequent production of oxalate and urolithiasis. Here, we generated a novel rat model of primary hyperoxaluria type I that carries a D205N mutation in the partially humanized Agxt gene through the CRISPR/Cas9 system. The AgxtD205N mutant rats showed undetectable alanine glyoxylate aminotransferase protein expression, developed hyperoxaluria at 1 month of age and exhibited severe renal calcium oxalate deposition after ethylene glycol challenge. This suggests our novel model is more relevant to the human disease than existing animal models. To test whether this model could be used for the development of innovative therapeutics, SaCas9 targeting hydroxyacid oxidase 1, responsible for metabolizing glycolate into glyoxylate, was delivered via adeno-associated viral vectors into newborn rats with primary hyperoxaluria type 1. This approach generated nearly 30% indels in the Hao1 gene in the liver, leading to 42% lower urine oxalate levels in the treated group than in the control group and preventing the rats with primary hyperoxaluria type 1 from undergoing severe nephrocalcinosis for at least 12 months. Thus, our results demonstrate that this partially humanized AgxtD205N rat strain is a high-performing model of primary hyperoxaluria type 1 for understanding pathology, and the development of novel therapeutics, such as reprogramming of the metabolic pathway through genome editing.

The Impact of Biliary Reconstruction Methods on Small Partial Liver Grafts

Supplemental Digital Content is available in the text.

Graft recipient weight ratios are lower in adult-to-adult living-donor liver transplantation than in adult-to-adult deceased-donor liver transplantation. Rapid liver regeneration is essential for increased recipient survival rates in adult-to-adult living-donor liver transplantation. However, the influence of biliary reconstruction methods, including choledocho-choledochostomy and choledocho-jejunostomy, on small partial liver grafts remains unknown. Herein, we investigate the impact of these biliary reconstruction methods on small partial liver grafts.

Perturbations of urea cycle enzymes during posthepatectomy rat liver failure

Posthepatectomy liver failure (PHLF) may occur after extended partial hepatectomy (PH). If malignancy is widespread in the liver, the size of PH and hence the size of the future liver remnant (FLR) may limit curability. We aimed to characterize differences in protein expression between different sizes of FLRs and identify proteins specific to the regenerative process of minimal-size FLR (MSFLR), with special focus on postoperative day (POD) 1 when PHLF is present. A total of 104 male Wistar rats were subjected to 30, 70, or 90% PH (MSFLR in rats), sham operation, or no operation. Blood and liver tissue were harvested at POD1, 3, and 5 (n = 8 per group). Protein expression was assessed by proteomic profiling by unsupervised two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) liquid chromatography tandem mass spectrometry (LC-MS/MS), followed by supervised selected reaction monitoring (SRM)-MS/MS. In all, 1,035 protein spots were detected, 54 of which were significantly differentially expressed between groups and identifiable. During PHLF after PH(90%) at POD1, urea cycle and related proteins showed significant perturbations, including the urea cycle flux-regulating enzyme of carbamoyl phosphate synthase-1, ornithine transcarbamylase, and arginase-1, as well as the ornithine aminotransferase and propionyl-CoA carboxylase alpha chain. Plasma-ammonia increased significantly at POD1 after PH(90%), followed by a prompt decrease. At the protein level, we found perturbations of urea cycle and related enzymes in the MSFLR during PHLF. Our results suggest that these perturbations may augment urea cycle function, which may be pivotal for increased ammonia elimination after extensive PHs and potential PHLF.NEW & NOTEWORTHY Posthepatectomy liver failure (PHLF) is associated with high mortality. In a rat model of 90% hepatectomy, PHLF is present. Our results on liver tissue proteomics suggest that the ability of the liver remnant to sufficiently eliminate ammonia may be brought about by perturbation related to urea cycle proteins and that enhancing the urea cycle capacity may play a key role in surviving PHLF.