Development of an experimental model of portal vein ligation associated with parenchymal transection (ALPPS) in rats. Cir Esp. 2014;92:676-681. [PMID: 25064517 DOI: 10.1016/j.ciresp.2013.11.005]

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.

Liver structural transformation after partial hepatectomy and repeated partial hepatectomy in rats: A renewed view on liver regeneration

BACKGROUND

The phenomenon of liver regeneration after partial hepatectomy (PH) is still a subject of considerable interest due to the increasing frequency of half liver transplantation on the one hand, and on the other hand, new surgical approaches which allow removal of massive space-occupying hepatic tumors, which earlier was considered as inoperable. Interestingly, the mechanisms of liver regeneration are extensively studied after PH but less attention is paid to the architectonics of the regenerated organ. Because of this, the question “How does the structure of regenerated liver differ from normal, regular liver?” has not been fully answered yet. Furthermore, almost without any attention is left the liver's structural transformation after repeated hepatectomy (of the re-regenereted liver).

AIM

To compare the architectonics of the lobules and circulatory bed of normal, re-generated and re-regenerated livers.

METHODS

The livers of 40 adult, male, albino Wistar rats were studied. 14 rats were subjected to PH - the 1^st study group (SG1); 10 rats underwent repeated PH – the 2^nd study group (SG2); 16 rats were subjected to sham operation - control group (CG); The livers were studied after 9 months from PH, and after 6 months from repeated PH. Cytological (Schiff reaction for the determination of DNA concen-tration), histological (H&E, Masson trichrome, CK8 Immunohistochemical marker, transparent slides after Indian Ink injection, ), morphometrical (hepatocytes areas, perimeters and ploidy) and Electron Microscopical (Scanning Electron Microscopy of corrosion casts) methods were used.

RESULTS

In the SG1 and SG2, the area of hepatocytes and their perimeter are increased compared to the CG (P < 0.05). However, the areas and perimeters of the hepatocytes of the SG₁ and SG₂ groups reveal a lesser difference. In regenerated (SG₁) and re-regenerated (SG₂) livers, the hepatocytes form the remodeled lobules, which size (300-1200 µm) exceeds the sizes of the lobules from CG (300-600 µm). The remodeled lobules (especially the “mega-lobules” with the sizes 1000-1200 µm) contain the transformed meshworks of the sinusoids, the part of which is dilated asymmetrically. This meshwork might have originated from the several portal venules (interlobular and/or inlet). The boundaries between the adjacent lobules (including mega-lobules) are widened and filled by connective tissue fibers, which gives the liver parenchyma a nodular look. In SG₂ the unevenness of sinusoid diameters, as well as the boundaries between the lobules (including the mega-lobules) are more vividly expressed in comparison with SG₁. The liver tissue of both SG₁ and SG₂ is featured by the slightly expressed ductular reaction.

CONCLUSION

Regenerated and re-regenerated livers in comparison with normal liver contain hypertrophied hepatocytes with increased ploidy which together with transformed sinusoidal and biliary meshworks form the remodeled lobulli.

A preliminary study of associating liver partition and portal vein ligation for staged hepatectomy in a rat model of liver cirrhosis

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) in a rat model of liver cirrhosis has not, to the best of our knowledge, been previously investigated. The present study therefore aimed to establish a model of ALPPS in cirrhotic rats and to assess liver regeneration. Rats were randomly divided into an ALPPS group with carbon tetrachloride-induced cirrhosis (group A) and a normal liver (group B). Rat weight, cytokine levels, biochemical parameters and histopathology were assessed 1, 2, 3, 7 and 14 days after ALPPS. Higher aspartate aminotransferase and alanine aminotransferase levels were detected in group A on the first postoperative day. On the first, second and third days, hepatocyte proliferation rate was higher in group B than in group A. After 3 days, hepatocyte proliferation rate in group B began to decrease, but the rate in group A continued to increase until the 14th day. Higher levels of hepatocyte growth factor, interleukin-6 and tumor necrosis factor-α were detected in group A compared with group B, but the differences were not significant. The present study demonstrated that ALPPS promoted liver regeneration in a rat model of cirrhosis, but significantly impaired liver function. Compared with the ALPPS model, group B exhibited a delayed peak of proliferation. The mechanism of liver regeneration induced by ALPPS in cirrhotic rats may be associated with increased cytokine levels.

Associating liver partition and portal vein ligation for staged hepatectomy: establishment of an animal model with insufficient liver remnant

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) allows extended hepatectomy in patients with an extremely small future liver remnant (FLR). Current rodent models of ALPPS do not include resection resulting in insufficient-for-survival FLR, or they do incorporate liver mass reduction prior to ALPPS. Differences in FLR volume and surgical procedures could bias our understanding of physiological and hemodynamic mechanisms. We aimed to establish a rat ALPPS model with minimal FLR without prior parenchymal resection. In rodents, the left median lobe (LML) represents 10% of total liver. Partial hepatectomy (PHx) sparing LML and pericaval parenchyma represents our reference 87% resection. The first step in the procedure is either portal vein ligation (PVL) corresponding to ligation of all but the LML portal branches, or PVL with transection between the left and right median lobe segments (PVLT), and is defined as ALPPS stage-1. Second, ligated lobes were removed: PVL-PHx represents a conventional 2-stage hepatectomy, while PVLT followed by PHx is a strict reproduction of human ALPPS. In Group A, liver hypertrophy was analyzed after PVL (n = 38), PVLT (n = 47), T (n = 10), and sham (n = 10); In group B, mortality and FLR hypertrophy was assessed after PHx (n = 42), Sham-PHx (n = 6), PVL-PHx (n = 37), and PVLT-PHx (n = 45). In group A, PVLT induced rapid FLR hypertrophy compared to PVL (p < 0,05). Hepatocyte proliferation was higher in PVLT remnants (p < 0,05). In group B, PHx had a 5-day mortality rate of 84%. Sham operation prior to PHx did not improve survival (p = 0.23). In both groups, major fatalities occurred within 48 h after resection. PVL or PVLT prior to PHx reduced mortality to 33.3% (p = 0,007) or 25% (p = 0.0002) respectively, with no difference between the 2 two-stage procedures (p = 0.6). 7-day FLR hypertrophy was higher after the PVLT-PHx compared to PVL-PHx and PHx (p = 0.024). Our model reproduces human ALPPS with FLR that is insufficient for survival without liver resection prior to the stage-1 procedure. It offers an appropriate model for analyzing the mechanisms driving survival rescue and increased hypertrophy.

NAFLD Induction Delays Postoperative Liver Regeneration of ALPPS in Rats

BACKGROUND

Associating liver partition and portal vein ligation (ALPPS) is a promising two-step hepatectomy that is beneficial for accumulative regeneration of the future liver remnant (FLR) and avoids postoperative liver failure.

AIMS

Our study aimed to evaluate whether nonalcoholic fatty liver disease affected the liver regeneration induced by ALPPS.

METHODS

Sprague-Dawley rats fed a high-fat diet were used to construct the NAFLD model. ALPPS were performed, and blood and future liver remnant samples were collected at postoperative days 1 (POD1), POD3, and POD7.

RESULTS

The hepatic regeneration rate (HRR) of ALPPS was higher than that of portal vein ligation (PVL) at POD3 and POD7 (p < 0.05), and the number of Ki-67-positive hepatocytes (POD3) and CD68-positive Kupffer cells (POD7) per visual field was higher in the ALPPS group than in the PVL group (p < 0.05). The serum TNF-α, hepatocyte growth factor protein, and the serum IL-6 level were higher in the ALPPS group than in the PVL group at POD3 and POD7. Compared with those of the standard laboratory diet (SLD)-fed rats, the rats with NAFLD exhibited a decrease in the HRR, Ki-67-positive hepatocytes, and CD68-positive Kupffer cells in the FLR. The number of CD68-positive Kupffer cells was lower in rats with NAFLD than that in SLD-fed rats; noteworthily, the serum level of IL-6 and TNF-α changed dramatically after surgeries.

CONCLUSIONS

NAFLD induction delayed liver regeneration induced by the ALPPS procedure, which might be associated with hepatocyte proliferation and the number of Kupffer cells.

Hepatic regeneration by associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is feasible but attenuated in rat liver with thioacetamide-induced fibrosis

BACKGROUND

The associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) procedure promotes the proliferation of the future liver remnant, but evidence to support the feasibility of ALPPS in livers with fibrosis is needed. Therefore the aim of this study was to establish a fibrotic ALPPS model in the rat to compare the capacity of regeneration in the remnant liver with or without fibrosis.

METHODS

In our study we first established a thioacetamide-induced fibrotic ALPPS model in rats. Then the ALPPS-induced regenerative capacities of normal and fibrotic liver were compared in this animal model. In addition, markers of regeneration, including the proliferative index and cyclin D1 and proliferating cell nuclear antigen levels, as well as various indicators of liver function were determined to evaluate the quality of the hepatic regeneration.

RESULTS

Compared with that of the sham group (opening of the peritoneal cavity with no further operative manipulation), the proliferation of the future liver remnant in fibrotic rat liver after the ALPPS procedure was increased on postoperative days 1, 2, and 5 (P < .039 each). In addition, the proliferative response was greater in the ALPPS group than in the ligation group subjected only to portal vein ligation of the left lateral, left middle, right, and caudate lobes (P = .099, P = .006, and P = .020 on postoperative days 1, 2, and 5, respectively). In contrast, the ALPPS-induced regenerative capacity in the fibrotic rat livers was attenuated compared with that in the normal liver on postoperative days 1, 2, and 5 (P < .031 for each) after stage I and on postoperative day 5 after stage II of the ALPPS procedure (P < .005). This attenuated the recovery of liver function, and the greater mortality rate indicated that functional proliferation was either delayed or not as extensive in the fibrotic rat livers.

CONCLUSION

Through establishing a rat model of thioacetamide-induced liver fibrosis, we found that ALPPS-derived liver regeneration was present and feasible in fibrotic livers, but this effect was attenuated compared with that in normal liver.

Assessment of liver regeneration after associating liver partition and portal vein ligation for staged hepatectomy: a comparative study with portal vein ligation

BACKGROUND

To investigate the diagnostic value of diffusion kurtosis imaging (DKI) and diffusion-weighted imaging (DWI) in assessing liver regeneration after associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) compared with portal vein ligation (PVL).

METHODS

Thirty rats were divided into the ALPPS, PVL, and control groups. DKI and DWI were performed before and 7 days after surgery. Corrected apparent diffusion (D), kurtosis (K) and apparent diffusion coefficient (ADC) were calculated and compared, radiologic-pathologic correlations were evaluated.

RESULTS

The volume of the right median lobe increased significantly after ALPPS. There were larger cellular diameters after ALPPS and PVL (P = 0.0003). The proliferative indexes of Ki-67 and hepatocyte growth factor were higher after ALPPS (P = 0.0024/0.0433). D, K and ADC values differed between the groups (P = 0.021/0.0015/0.0008). A significant correlation existed between D and the hepatocyte size (r = -0.523), no correlations existed in ADC and K (P = 0.159/0.111). The proliferative indexes showed moderate negative correlations with ADC (r = -0.484/-0.537) and no correlations with D and K (P = 0.100-0.877).

DISCUSSION

Liver regeneration after ALPPS was effective and superior to PVL. DKI, especially the D map, may provide added value in evaluating the microstructure of liver regeneration after ALPPS, but this model alone may perform no better than the standard monoexponential model of DWI.

Maturity of associating liver partition and portal vein ligation for staged hepatectomy-derived liver regeneration in a rat model

AIM

To establish a rat model for evaluating the maturity of liver regeneration derived from associating liver partition and portal vein ligation for staged hepatectomy (ALPPS).

METHODS

In the present study, ALPPS, partial hepatecotmy (PHx), and sham rat models were established initially, which were validated by significant increase of proliferative markers including Ki-67, proliferating cell nuclear antigen, and cyclin D1. In the setting of accelerated proliferation in volume at the second and fifth day after ALPPS, the characteristics of newborn hepatocytes, as well as specific markers of progenitor hepatic cell, were identified. Afterwards, the detection of liver function followed by cluster analysis of functional gene expression were performed to evaluate the maturity.

RESULTS

Compared with PHx and sham groups, the proliferation of FLR was significantly higher in ALPPS group (P = 0.023 and 0.001 at second day, P = 0.034 and P < 0.001 at fifth day after stage I). Meanwhile, the increased expression of proliferative markers including Ki-67, proliferating cell nuclear antigen, and cyclin D1 verified the accelerated liver regeneration derived from ALPPS procedure. However, ALPPS-induced Sox9 positive hepatocytes significantly increased beyond the portal triad, which indicated the progenitor hepatic cell was potentially involved. And the characteristics of ALPPS-induced hepatocytes indicated the lower expression of hepatocyte nuclear factor 4 and anti-tryptase in early proliferative stage. Both suggested the immaturity of ALPPS-derived liver regeneration. Additionally, the detection of liver function and functional genes expression confirmed the immaturity of renascent hepatocytes derived in early stage of ALPPS-derived liver regeneration.

CONCLUSION

Our study revealed the immaturity of ALPPS-derived proliferation in early regenerative response, which indicated that the volumetric assessment overestimated the functional proliferation. This could be convincing evidence that the stage II of ALPPS should be performed prudently in patients with marginally adequate FLR, as the ALPPS-derived proliferation in volume lags behind the functional regeneration.

Rapid Liver Hypertrophy After Portal Vein Occlusion Correlates with the Degree of Collateralization Between Lobes-a Study in Pigs

BACKGROUND

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) induces more rapid liver growth than portal vein ligation (PVL). Transection of parenchyma in ALPPS may prevent the formation of collaterals between lobes. The aim of this study was to determine if abrogating the formation of collaterals through parenchymal transection impacted growth rate.

METHODS

Twelve Yorkshire Landrace pigs were randomized to undergo ALPPS, PVL, or "partial ALPPS" by varying degrees of parenchymal transection. Hepatic volume was measured after 7 days. Portal blood flow and pressure were measured. Portal vein collaterals were examined from epoxy casts.

RESULTS

PVL, ALPPS, and partial ALPPS led to volume increases of the RLL by 15.5% (range 3-22), 64% (range 45-76), and 32% (range 18-77), respectively, with significant differences between PVL and ALPPS/partial ALPPS (p < 0.05). In PVL and partial ALPPS, substantial new portal vein collaterals were found. The number of collaterals correlated inversely with the growth rate (p = 0.039). Portal vein pressure was elevated in all models after ligation suggesting hyperflow to the portal vein-supplied lobe (p < 0.05).

CONCLUSIONS

These data suggest that liver hypertrophy following PVL is inversely proportional to the development of collaterals. Hypertrophy after ALPPS is likely more rapid due to reduction of collaterals through transection.

Associating liver partition and portal vein ligation for staged hepatectomy versus conventional two-stage hepatectomy: a systematic review and meta-analysis

Background

It is generally accepted that an insufficient future liver remnant is a major limitation of large-scale hepatectomy for patients with primary hepatocellular carcinoma. Conventional two-stage hepatectomy (TSH) is commonly considered to accelerate future liver regeneration despite its low regeneration rate. Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS), which is characterized by a rapid regeneration, has brought new opportunities.

Methods

Relevant studies were identified by searching the selected databases up to September 2017. Then, a meta-analysis of regeneration efficiency, complication rate, R0 resection ratio, and short-term outcomes was performed.

Results

Ten studies, comprising 719 patients, were included. The overall analysis showed that ALPPS was associated with a larger hyperplastic volume and a shorter time interval (P < 0.00001) than TSH. ALPPS also exhibited a higher completion rate for second-stage operations (odds ratio, OR 9.50; P < 0.0001) and a slightly higher rate of R0 resection (OR 1.90; P = 0.11). Interestingly, there was no significant difference in 90-day mortality between the two treatments (OR 1.44; P = 0.35).

Conclusions

These results indicate that compared with TSH, ALPPS possesses a stronger regenerative ability and better facilitates second-stage operations. However, the safety, patient outcomes, and patient selection for ALPPS require further study.

Electronic supplementary material

The online version of this article (10.1186/s12957-017-1295-0) contains supplementary material, which is available to authorized users.

Rat Model of the Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy (ALPPS) Procedure

Recent clinical data support an aggressive surgical approach to both primary and metastatic liver tumors. For some indications, like colorectal liver metastases, the amount of liver tissue left behind after liver resection has become the main limiting factor of resectability of large or multiple liver tumors. A minimal amount of functional tissue is required to avoid the severe complication of post-hepatectomy liver failure, which has high morbidity and mortality. Inducing liver growth of the prospective remnant prior to resection has become more established in liver surgery, either in the form of portal vein embolization by interventional radiologists or in the form of portal vein ligation several weeks prior to resection. Recently, it was shown that liver regeneration is more extensive and rapid, when the parenchymal transection is added to portal vein ligation in a first stage and then, after only one week of waiting, resection performed in a second stage (Associating Liver Partition and Portal vein ligation for Staged hepatectomy = ALPPS). ALPPS has rapidly become popular across the world, but has been criticized for its high perioperative mortality. The mechanism of accelerated and extensive growth induced by this procedure has not been well understood. Animal models have been developed to explore both the physiological and molecular mechanisms of accelerated liver regeneration in ALPPS. This protocol presents a rat model that allows mechanistic exploration of accelerated regeneration.

A new technique for accelerated liver regeneration: An experimental study in rats

BACKGROUND

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is used to accelerate growth of the future liver remnant. We investigated alternative methods for increasing the future liver remnant.

METHODS

A total of 152 rats were randomized as follows: (1) sham; (2) portal vein ligation; (3) portal vein ligation/surgical split (ALPPS); (4) portal vein ligation/split of the liver with a radiofrequency ablation needle; (5) portal vein ligation/radiofrequency ablation of the deportalized liver (portal vein ligation/radiofrequency ablation necrosis in the deportalized liver); (6) portal vein ligation/radiofrequency ablation of the future liver remnant (portal vein ligation/radiofrequency ablation-future liver remnant); and (7) controls. Animals were evaluated on postoperative days 2 and 4. Bodyweight, liver parameters, hepatic regeneration rate, proinflammatory cytokines, hepatocyte proliferation, and gene expression were measured.

RESULTS

Hepatic regeneration rate indicated a steady increase in all intervention groups compared with sham rats (P < .001). At postoperative day 2, the hepatic regeneration rate was significantly higher in the portal vein ligation/radiofrequency ablation necrosis in the deportalized liver group than in the portal vein ligation group (P = .039). On postoperative day 4, we found significant differences between the portal vein ligation group and the ALPPS (P = .015), portal vein ligation/split of the liver with a radiofrequency ablation needle (P = .010), and portal vein ligation/radiofrequency ablation necrosis in the deportalized liver (P = .046) groups. Hepatocyte proliferation was significantly higher at all times compared with sham rats. On postoperative day 4, we found a significantly higher proliferation in groups 3, 4, 5, and 6 compared to portal vein ligation. Gene analysis revealed upregulation of genes involved in cellular proliferation and downregulation of genes involved in cellular homeostasis in all intervention groups. Between the intervention groups, gene expression was nearly identical. Biochemical markers and proinflammatory cytokines were comparable between groups.

CONCLUSION

The surplus liver regeneration after ALPPS is probably mediated through parenchymal damage and subsequent release of growth stimulators, which again upregulates genes involved in cellular regeneration and downregulates genes involved in cellular homeostasis. We also demonstrate that growth of the future liver remnant, comparable to that seen after ALPPS, could be achieved by radiofrequency ablation treatment of the deportalized liver, that is, a procedure in which the initial step in humans can be performed percutaneously.

Animal Models for Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy (ALPPS): Achievements and Future Perspectives

Background: Since 2012, Associated Liver Partition and Portal vein ligation for Staged hepatectomy (ALPPS) has been standing in the limelight of modern liver surgery and numerous questions have been raised regarding this novel approach. On the one hand, ALPPS has proved to be a valuable method in the treatment of hepatic tumors, while on the other hand, there are many controversies, such as high mortality and morbidity rates. Further surgical research is essential for a better understanding of underlying mechanisms and for enhancing patient safety. Summary: Until recently, only 8 animal models have been created with the purpose to mimic ALPPS-induced liver regeneration. From these 7 are rodent (6 rat and 1 mouse) models, while only 1 is a large animal model, which uses pigs. In case of rodent models, portal flow deprivation of 75-90% is achieved via portal vein ligation leaving only the right (20-25%) or left median (10-15%) lobes portally perfused, while liver splitting in general is carried out positioned according to the falciform ligament. As for the swine model, the left lateral and medial lobes (70-75% of total liver volume) are portally ligated, and the right lateral lobe (accounting for 20-24% of the parenchyma) is partially resected in order to reach critical liver volume. Each model is capable of reproducing the accelerated liver regeneration seen in human cases. However, all species have significantly different liver anatomy compared with the human anatomic situation, making clinical translation somewhat difficult. Key Messages: Unfortunately, there are no perfect animal models available for ALPPS research. Small animal models are inexpensive and well suited for basic research, but may only provide limited translational potential to humans. Clinically large animal models may provide more relevant data, but currently no suitable one exists.

Mechanistic insights of rapid liver regeneration after associating liver partition and portal vein ligation for stage hepatectomy

AIM

To highlight the potential mechanisms of regeneration in the Associating Liver Partition and Portal vein ligation for Stage hepatectomy models (clinical and experimental) that could unlock the myth behind the extraordinary capability of the liver for regeneration, which would help in designing new therapeutic options for the regenerative drive in difficult setup, such as chronic liver diseases. Associating Liver Partition and Portal vein ligation for Stage hepatectomy has been recently advocated to induce rapid future liver remnant hypertrophy that significantly shortens the time for the second stage hepatectomy. The introduction of Associating Liver Partition and Portal vein ligation for Stage hepatectomy in the surgical armamentarium of therapeutic tools for liver surgeons represented a real breakthrough in the history of liver surgery.

METHODS

A comprehensive literature review of Associating Liver Partition and Portal vein ligation for Stage hepatectomy and its utility in liver regeneration is performed.

RESULTS

Liver regeneration after Associating Liver Partition and Portal vein ligation for Stage hepatectomy is a combination of portal flow changes and parenchymal transection that generate a systematic response inducing hepatocyte proliferation and remodeling.

CONCLUSION

Associating Liver Partition and Portal vein ligation for Stage hepatectomy represents a real breakthrough in the history of liver surgery because it offers rapid liver regeneration potential that facilitate resection of liver tumors that were previously though unresectable. The jury is still out though in terms of safety, efficacy and oncological outcomes. As far as Associating Liver Partition and Portal vein ligation for Stage hepatectomy -induced liver regeneration is concerned, further research on the field should focus on the role of non-parenchymal cells in liver regeneration as well as on the effect of Associating Liver Partition and Portal vein ligation for Stage hepatectomy in liver regeneration in the setup of parenchymal liver disease.

Establishment of a rat model: Associating liver partition with portal vein ligation for staged hepatectomy

BACKGROUND

We adapted the anatomically oriented parenchyma-preserving resection technique for associating liver partition with portal vein ligation (PVL) for staged hepatectomy (ALPPS) in rats and examined the role of revascularization in intrahepatic size regulation.

METHODS

We performed the procedures based on anatomic study. The ALPPS procedure consisted of a 70% PVL (occluding the left median, left lateral, and right lobes), parenchymal transection (median lobe) and partial (10%) hepatectomy (PHx; caudate lobe). The transection effect was evaluated by measuring the extent of hepatic atrophy or regeneration of individual liver lobes in the ALPPS and control groups (70% PVL and 10% PHx without transection). The survival rates after stage II resection and collateral formation within the portal vein system was examined.

RESULTS

Anatomic study revealed a close spatial relationship between the demarcation line and the middle median hepatic vein. This enabled placing the transection plane without injuring the hepatic vein. Transection was achieved via stepwise clamping, followed by 2-3 parenchyma-preserving piercing sutures on both sides of the clamp. Ligated liver lobes atrophy was significantly enhanced after ALPPS compared with the control group. In contrast, both a significantly greater relative weight of the regenerated lobe and proliferation index on the first postoperative day were observed. All animals tolerated stage II-resection without complications. Portoportal collaterals were only observed in the control group.

CONCLUSION

We developed an anatomically precise technique for parenchymal transection. The lack of a dense vascular network between the portalized and deportalized lobes may play an important role in accelerating regeneration and atrophy augmentation.

A preliminary study of ALPPS procedure in a rat model

Associating Liver Partition and Portal vein ligation for Staged hepatectomy (ALPPS) has been reported to be a novel surgical technique that provides fast and effective growth of liver remnant. Despite occasional reports on animal studies, the mechanisms of rapid liver regeneration in ALPPS remains unclear. In the present study, we intend to develop a reproducible rat model to mimick ALPPS and to explore the underlying mechanisms. Rats assigned to the portal vein ligation (PVL), left lateral lobe (LLL) resection, transection and sham groups served as controls. Results indicated that the regeneration rate in the remnant liver after ALPPS was two times relative to PVL, whereas rats with transection alone showed minimal volume increase. The expression levels of Ki-67 and PCNA were about ten-fold higher after ALPPS compared with the transection and LLL resection groups, and four-fold higher compared with the PVL group. The levels of TNF-α, IL-6 and HGF in the regenerating liver remnant were about three-fold higher after ALPPS than the controls. There was a more significant activation of NF-κB p65, STAT3 and Yap after ALPPS, suggesting synergistic activation of the pathways by PVL and transection, which might play an important role in liver regeneration after ALPPS.

A novel rat model of liver regeneration: possible role of cytokine induced neutrophil chemoattractant-1 in augmented liver regeneration

Background

Liver resection is the mainstay of treatment for most of the liver tumors. Liver has a unique capability to restore the lost volume following resection, however, most of the primary tumors grow in a liver with preexisting parenchymal diseases and secondary tumors often present in multiple liver lobes precluding a safe curative resection. Two-stage hepatectomy and portal vein ligation (PVL) are used to achieve a safer future remnant liver volume (FRLV), however, these procedures take several weeks to achieve adequate FRLV. A recently introduced faster alternative two-stage hepatectomy, also know as associated liver partitioning and portal vein ligation for staged hepatectomy (ALPPS), produces a desirable FRLV in days.

Methods

To have an insight into the mechanism of ALPPS associated liver regeneration, we reproduced a rat model of ALPPS and compared the results with the PVL group.

Results

Our results convincingly showed an advantage of the ALPPS procedure over PVL group in terms of early regeneration, however, in 1-week time the amount of regeneration was comparable. An early regeneration in the ALPPS group coincided with an early entry of hepatocytes into the cell proliferation phase, a significant increase in portal pressure and increase in hepatic enzymes in the ALPPS group compared with the PVL group. According to the protein array evaluation of 29 cytokines/chemokines, cytokine induced neutrophil chemoattractant-1 had the highest expression whereas IL-6 had the highest fold (>6 vs PVL group) expression at the early phase of regeneration in the ALPPS group.

Conclusions

This unique rat model of ALPPS would help to improve our understanding about the liver generation process and also will help in further refinement of the ALPPS procedure for the clinical benefit.

Electronic supplementary material

The online version of this article (doi:10.1186/s13022-015-0020-3) contains supplementary material, which is available to authorized users.