NAFLD Induction Delays Postoperative Liver Regeneration of ALPPS in Rats

Correlation between the liver transection line localization and future liver remnant hypertrophy in associating liver partition and portal vein ligation for staged hepatectomy

Background and aims

Colorectal liver metastases (CRLMs) represent the most prevalent form of secondary liver tumors, and insufficient future liver remnant (FLR) often leads to unresectability. To tackle this challenge, various methods for stimulating liver hypertrophy have been developed including portal vein embolization (PVE), associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) and the newest one, liver venous deprivation (LVD). ALPPS was thoroughly studied over the last decade and it has been shown to induce rapid and intensive FLR hypertrophy. The objective of this study was to assess whether the localization of the liver transection line during the initial stage of ALPPS correlates with the degree of FLR hypertrophy.

Methods

A retrospective, multicentric study was conducted, and we analyzed all consecutive patients with CRLMs who underwent ALPPS over the eight-year period. Patients were categorized into two groups based on the type of resection-right trisectionectomy (ERH) or right hemihepatectomy (RH) respectively. The degree of hypertrophy (DH), its correlation with FLR and postoperative outcomes were assessed.

Results

The cohort consisted of 136 patients (72 in the ERH group and 64 in the RH group). Baseline characteristics, hypertrophy interval, and total liver volume showed no significant differences between the groups. DH was greater in the ERH group (83.2% vs. 62.5%, p = 0.025). A strong negative correlation was observed between FLR volume and DH in both groups. Postoperative outcomes and one-year survival were comparable between the groups.

Conclusions

FLR hypertrophy is influenced by the localization of the liver transection line in ALPPS. Furthermore, correlation analysis indicated that a smaller estimated FLR is associated with greater DH. No statistical difference in outcomes was noted between the groups.

Impact of high-fat diet and exposure to constant light on reproductive competence of female ICR mice

Obesity and exposure to light at night are prevalent in modern society and associated with changes in physiology and behavior that can affect a female's ability to support offspring growth during pregnancy and lactation. A 2X3 factor study of ICR mice was conducted to determine the effect of diet [control (CON; 10% fat) or high fat (HF; 60% fat)] and exposure to regular 12 h light:dark cycles (LD) or continuous low (L5) or high (L100) lux of light on gestation length, birth litter size, milk composition and litter growth to lactation day 12. HF diet reduced birth litter size, but increased postnatal d 12 litter weight (P<0.05), whereas constant light tended to increase litter weight (P=0.07). Continuous light increased gestation length, altered dam feed intake, increased serum prolactin and increased final dam and mammary gland weight (P<0.05), while decreasing mammary ATP content and milk lactose (P<0.05). Correlation analysis indicated a positive relationship between final litter weight and mammary size, metabolic stores (e.g. maternal fat pad weight), kcal of feed intake, and gestation length (P<0.05). Although CON mice spent more time eating than HF dams, the calorically dense HF diet was related to greater rates of litter growth to peak lactation. Constant light circadian disrupting effects appear to be confounded by a potential long day photoperiod response exemplified by higher circulating levels of prolactin and increased body and mammary weight of females exposed to these conditions. Other model systems may be better to study the interacting effects of obesity and circadian disruption on reproductive competence.

Lipid droplet deposition in the regenerating liver: A promoter, inhibitor, or bystander?

Liver regeneration (LR) is a complex process involving intricate networks of cellular connections, cytokines, and growth factors. During the early stages of LR, hepatocytes accumulate lipids, primarily triacylglycerol, and cholesterol esters, in the lipid droplets. Although it is widely accepted that this phenomenon contributes to LR, the impact of lipid droplet deposition on LR remains a matter of debate. Some studies have suggested that lipid droplet deposition has no effect or may even be detrimental to LR. This review article focuses on transient regeneration-associated steatosis and its relationship with the liver regenerative response.

Corosolic acid inhibits tumour growth without compromising associating liver partition and portal vein ligation-induced liver regeneration in rats

BACKGROUND

Associating liver partition and portal vein ligation (ALPPS) technique is a promising strategy for unresectable primary liver tumours without sufficient future liver remnants (FLRs).

OBJECTIVE

Our study explored the effect of corosolic acid (CA) on inhibiting tumour growth without compromising ALPPS-induced liver regeneration.

METHODS

The ALPPS procedure was performed in Sprague-Dawley rats with orthotopic liver cancer. Blood, tumour, and FLR samples were collected, and the effect of CA on the inhibition of tumour progression and ALPPS-induced liver regeneration, and its possible mechanism, were investigated.

RESULTS

The tumour weight in the implantation/ALPPS group was higher than in the implantation without ALPPS group (p < .05), and the tumour weight in the implantation/ALPPS/CA group was lower than in the implantation/ALPPS group (p < .05). On postoperative day 15, the hepatic regeneration rate, and the expression of Ki67+ hepatocytes in the FLRs had increased significantly in the group that underwent ALPPS. The number of cluster of differentiation (CD) 86+ macrophages markedly increased in the FLRs and in the tumours of groups that underwent the ALPPS procedure. Additionally, the number of CD206+ macrophages was higher than the number of CD86+ macrophages in the tumours of the implantation and the implantation/ALPPS groups (p < .01, respectively); however, the opposite results were observed in the CA groups. The administration of CA downregulated the expression of transforming growth factor-beta (TGF-β), CD31, and programmed cell death protein 1 (PD-1) but increased the number of CD8+ lymphocytes in tumours.

CONCLUSION

Corosolic acid inhibits tumour growth without compromising ALPPS-induced liver regeneration. This result may be attributed to the CA-induced downregulation of PD-1 and TGF-β expression and the increased CD8+ lymphocyte infiltration in tumour tissue associated with the suppression of M2 macrophage polarisation. Key MessagesThis study aimed to investigate the effect of CA on ALPPS-induced liver regeneration and hepatic tumour progression after ALPPS-induced liver regeneration.Corosolic acid inhibits tumour growth without compromising ALPPS-induced liver regeneration. This result may be attributed to the CA-induced downregulation of PD-1 and TGF-β expression and the increased CD8+ lymphocyte infiltration in tumour tissue associated with the suppression of M2 macrophage polarisation.

Evolution of associating liver partition and portal vein ligation for staged hepatectomy from 2012 to 2021: A bibliometric analysis. Review

BACKGROUND

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) has become increasingly popular during the past few decades, and its indications have extended from patients with normal liver to post-chemotherapy patients and even patients with cirrhosis. However, few studies have assessed the publications in relation to ALPPS.

METHODS

Web of Science was searched to identify studies related to ALPPS published from 2012 to 2021. The analysis was performed using the bibliometric package (Version 3.1.0) in R software.

RESULTS

In total, 486 publications were found. These articles were published in 159 journals and authored by 2157 researchers from 694 organizations. The most prolific journal was Annals of Surgery (24 articles and 1170 citations). The most frequently cited article was published in Annals of Surgery (average citations, 72.7; total citations, 727). China was the most productive country for ALPPS publications but had comparatively less interaction with other countries. Both thematic evolution and co-occurrence network analysis showed low numbers of topics such as failure, resection, and safety among the publications but large numbers of highly cited papers on outcomes, prediction, mechanisms, multicenter analysis, and novel procedures such as liver venous deprivation. A total of 196 studies focused the clinical application of ALPPS, and most studies were IDEAL Stages I and II. The specific mechanism of ALPPS liver regeneration remains unclear.

CONCLUSIONS

This is the first bibliometric analysis offering an overview of the development of ALPPS research publications. Our findings identified prominent studies, countries, institutions, journals, and authors to indicate the future direction of ALPPS research. The role of ALPPS in liver regeneration and the long-term results of ALPPS need further study. Future research directions include comparison of ALPPS with portal vein embolization, liver venous deprivation, and other two-stage hepatectomies as well as patients' quality of life after ALPPS.

Folinic Acid Potentiates the Liver Regeneration Process after Selective Portal Vein Ligation in Rats

Simple Summary

Fewer than 30% of patients with liver metastases are eligible for major liver resection, because liver remaining after such a surgery would be insufficient to cover the patient’s needs; this is called a low percentage of future liver remnant (FLR). Folinic acid (FA) has been shown to play a crucial role in cellular synthesis, regeneration, and nucleotide and amino acid biosynthesis. The aim of this piece of research was to evaluate the effect of FA as a potential hypertrophic hepatic enhancer agent after selective portal vein ligation (PVL) to ensure adequate FLR. We have confirmed in our rodent model that FA accelerates liver regeneration after PVL and enhances recovery of liver function. These findings may allow more patients to be eligible for liver resection without jeopardizing postoperative liver function.

Abstract

Liver resection remains the gold standard for hepatic metastases. The future liver remnant (FLR) and its functional status are two key points to consider before performing major liver resections, since patients with less than 25% FLR or a Child–Pugh B or C grade are not eligible for this procedure. Folinic acid (FA) is an essential agent in cell replication processes. Herein, we analyze the effect of FA as an enhancer of liver regeneration after selective portal vein ligation (PVL). Sixty-four male WAG/RijHsd rats were randomly distributed into eight groups: a control group and seven subjected to 50% PVL, by ligation of left portal branch. The treated animals received FA (2.5 m/kg), while the rest were given saline. After 36 h, 3 days or 7 days, liver tissue and blood samples were obtained. FA slightly but significantly increased FLR percentage (FLR%) on the 7th day (91.88 ± 0.61%) compared to control or saline-treated groups (86.72 ± 2.5 vs. 87 ± 3.33%; p < 0.01). The hepatocyte nuclear area was also increased both at 36 h and 7days with FA (61.55 ± 16.09 µm², and 49.91 ± 15.38 µm²; p < 0.001). Finally, FA also improved liver function. In conclusion, FA has boosted liver regeneration assessed by FLR%, nuclear area size and restoration of liver function after PVL.

Verapamil induces autophagy to improve liver regeneration in non-alcoholic fatty liver mice

Verapamil can restore intracellular calcium homeostasis, increase the fusion of autophagosomes and lysosomes, reduce lipid droplet accumulation and inhibit inflammation and insulin resistance in high-fat-fed mice. The present study aimed to investigate verapamil's effect and its underlying liver regeneration mechanism in mice with non-alcoholic fatty liver. After 50% hepatectomy was performed, the changes of autophagy and liver regeneration were evaluated by detecting cell proliferation and autophagy at each time point. Then, 25mg/kg verapamil was injected intraperitoneally for 10 d before an operation in the mild to moderate fatty liver and severe fatty liver groups. The control group and mild to moderate fatty liver group reached the peak of proliferation at 24-48h after operation, and the mice with severe fatty liver and steatohepatitis reached the peak at 48-72h. Autophagy in the normal group and mild to moderate fatty liver group reached the peak 48 hours after operation. Verapamil injection can enhance autophagy, reduce the weight of fatty liver mice, improve liver function and liver regeneration. Verapamil can induce autophagy, improve hepatocyte function and promote hepatocyte regeneration through the mTOR independent signaling pathway, thus improving the process of liver regeneration after partial hepatectomy.

Modulation of Autophagy: A Novel "Rejuvenation" Strategy for the Aging Liver

Aging is a natural life process which leads to a gradual decline of essential physiological processes. For the liver, it leads to alterations in histomorphology (steatosis and fibrosis) and function (protein synthesis and energy generation) and affects central hepatocellular processes (autophagy, mitochondrial respiration, and hepatocyte proliferation). These alterations do not only impair the metabolic capacity of the liver but also represent important factors in the pathogenesis of malignant liver disease. Autophagy is a recycling process for eukaryotic cells to degrade dysfunctional intracellular components and to reuse the basic substances. It plays a crucial role in maintaining cell homeostasis and in resisting environmental stress. Emerging evidence shows that modulating autophagy seems to be effective in improving the age-related alterations of the liver. However, autophagy is a double-edged sword for the aged liver. Upregulating autophagy alleviates hepatic steatosis and ROS-induced cellular stress and promotes hepatocyte proliferation but may aggravate hepatic fibrosis. Therefore, a well-balanced autophagy modulation strategy might be suitable to alleviate age-related liver dysfunction. Conclusion. Modulation of autophagy is a promising strategy for "rejuvenation" of the aged liver. Detailed knowledge regarding the most devastating processes in the individual patient is needed to effectively counteract aging of the liver without causing obvious harm.

Mechanisms of nonalcoholic fatty liver disease and implications for surgery

Background

Nonalcoholic fatty liver disease (NAFLD) has become the most common form of chronic liver disease in both adults and children worldwide. Understanding the pathogenic mechanisms behind NAFLD provides the basis for identifying risk factors, such as metabolic syndrome, pancreatoduodenectomy, and host genetics, that lead to the onset and progression of the disease. The progression from steatosis to more severe forms, such as steatohepatitis, fibrosis, and cirrhosis, leads to an increased number of liver and non-liver complications.

Purpose

NAFLD-associated end-stage liver disease (ESLD) and hepatocellular carcinoma (HCC) often require surgery as the only curative treatment. In particular, the presence of NAFLD together with the coexisting metabolic comorbidities that usually occur in these patients requires careful preoperative diagnosis and peri-/postoperative management. Bariatric surgery, liver resection, and liver transplantation (LT) have shown favorable results for weight loss, HCC, and ESLD in patients with NAFLD. The LT demand and the increasing spread of NAFLD in the donor pool reinforce the already existing lack of donor organs.

Conclusion

In this review, we will discuss the diverse mechanisms underlying NAFLD, its implications for surgery, and the challenges for patient management.

Cell cycle regulation in NAFLD: when imbalanced metabolism limits cell division

Cell division is essential for organismal growth and tissue homeostasis. It is exceptionally significant in tissues chronically exposed to intrinsic and external damage, like the liver. After decades of studying the regulation of cell cycle by extracellular signals, there are still gaps in our knowledge on how these two interact with metabolic pathways in vivo. Studying the cross-talk of these pathways has direct clinical implications as defects in cell division, signaling pathways, and metabolic homeostasis are frequently observed in liver diseases. In this review, we will focus on recent reports which describe various functions of cell cycle regulators in hepatic homeostasis. We will describe the interplay between the cell cycle and metabolism during liver regeneration after acute and chronic damage. We will focus our attention on non-alcoholic fatty liver disease, especially non-alcoholic steatohepatitis. The global incidence of non-alcoholic fatty liver disease is increasing exponentially. Therefore, understanding the interplay between cell cycle regulators and metabolism may lead to the discovery of novel therapeutic targets amenable to intervention.

The Role of Autophagy for the Regeneration of the Aging Liver

Age is one of the key risk factors to develop malignant diseases leading to a high incidence of hepatic tumors in the elderly population. The only curative treatment for hepatic tumors is surgical removal, which initiates liver regeneration. However, liver regeneration is impaired with aging, leading to an increased surgical risk for the elderly patient. Due to the increased risk, those patients are potentially excluded from curative surgery. Aging impairs autophagy via lipofuscin accumulation and inhibition of autophagosome formation. Autophagy is a recycling mechanism for eukaryotic cells to maintain homeostasis. Its principal function is to degrade endogenous bio-macromolecules for recycling cellular substances. A number of recent studies have shown that the reduced regenerative capacity of the aged remnant liver can be restored by promoting autophagy. Autophagy can be activated via multiple mTOR-dependent and mTOR-independent pathways. However, inducing autophagy through the mTOR-dependent pathway alone severely impairs liver regeneration. In contrast, recent observations suggest that inducing autophagy via mTOR-independent pathways might be promising in promoting liver regeneration. Conclusion: Activation of autophagy via an mTOR-independent autophagy inducer is a potential therapy for promoting liver regeneration, especially in the elderly patients at risk.

Can Nonfibrotic Nonalcoholic Steatohepatitis Be Effectively Identified by Supersonic Shear Imaging?

Supersonic shear imaging (SSI) is a relatively new technique to measure the elasticity of target tissues based on the shear wave propagation. The aim of this study was to evaluate the value of SSI in discriminating nonfibrotic nonalcoholic steatohepatitis (NASH) from the less severe nonalcoholic fatty liver disease (NAFLD), NASH with fibrosis, and the normal liver, as well as the relationship between various NAFLD pathologic or biochemical findings and SSI liver elasticity. Rabbits with NAFLD of different degrees were subjected to SSI for liver elasticity measurement. Plasma was collected for biochemical examinations, and liver tissues were harvested for pathologic assessment. Results showed that liver elasticity of rabbits with nonfibrotic NASH was significantly different from that of rabbits with simple steatosis, borderline, NASH with fibrosis, and normal liver (P < 0.05) and the areas under the receiver operating characteristic curve of SSI for predicting nonfibrotic NASH and NASH with fibrosis were 0.997 and 0.967, respectively, and the optimal cutoff values were 10.17 kPa and 12.82 kPa, respectively. Multivariate analysis showed that only fibrosis and inflammation were the independent factors affecting liver elasticity of NAFLD (P ≤ 0.001), while inflammation, steatosis, and ballooning degeneration were all independently related to liver elasticity in rabbits without fibrosis (P < 0.01). In addition, alanine aminotransferase was the only biochemical factor independently related to liver elasticity (P ≤ 0.001). Our results indicate that SSI can effectively identify nonfibrotic NASH in rabbits based on the difference in liver elasticity and the difference is related to the various pathologic changes, including fibrosis, inflammation, steatosis, and ballooning degeneration.