Human liver regeneration after major hepatic resection. A study of normal liver and livers with chronic hepatitis and cirrhosis

Functional Liver Imaging Score (FLIS) as imaging parameter for predicting post-hepatectomy complications in patients with liver cirrhosis

BackgroundLiver dysfunction has been reported as a risk factor for predicting complications after hepatectomy. In patients with liver cirrhosis (LC) who underwent hepatectomy, a Functional Liver Imaging Score (FLIS), derived from gadoxetic acid-enhanced magnetic resonance imaging (MRI), has never been investigated as a predictor of clinically significant post-hepatectomy complications.PurposeTo evaluate whether FLIS can predict post-hepatectomy complications in patients with LC.Material and MethodsA retrospective review was conducted of patients with LC who underwent gadoxetic acid-enhanced MRI and hepatectomy. Univariable and multivariable logistic regression was used to identify clinicopathological and radiologic findings associated with the development of major complication (Clavien-Dindo classification [CDC] ≥ III). Receiver operating characteristic (ROC) curve analysis was performed to determine the cutoff value of FLIS for predicting CDC ≥ III.ResultsOf the finally included 106 patients (77 men; mean age = 62.5 ± 8.3 years), 12 patients had a CDC ≥ III. Multivariable analysis showed that only FLIS independently predicted post-hepatectomy complications (odds ratio = 0.02; P = 0.01). ROC analysis suggested the FLIS ≤ 4 was the optimal cutoff for predicting CDC ≥ III (AUC value = 0.94; sensitivity = 91.67%; specificity = 95.74%; positive likelihood ratio = 21.54; and negative likelihood ratio = 0.09).ConclusionIn patients with LC, FLIS was an independent predictor of post-hepatectomy complications. FLIS showed excellent diagnostic performance in predicting post-hepatectomy complications.

Superporous sponge prepared by secondary network compaction with enhanced permeability and mechanical properties for non-compressible hemostasis in pigs

Developing superporous hemostatic sponges with simultaneously enhanced permeability and mechanical properties remains challenging but highly desirable to achieve rapid hemostasis for non-compressible hemorrhage. Typical approaches to improve the permeability of hemostatic sponges by increasing porosity sacrifice mechanical properties and yield limited pore interconnectivity, thereby undermining the hemostatic efficacy and subsequent tissue regeneration. Herein, we propose a temperature-assisted secondary network compaction strategy following the phase separation-induced primary compaction to fabricate the superporous chitosan sponge with highly-interconnected porous structure, enhanced blood absorption rate and capacity, and fatigue resistance. The superporous chitosan sponge exhibits rapid shape recovery after absorbing blood and maintains sufficient pressure on wounds to build a robust physical barrier to greatly improve hemostatic efficiency. Furthermore, the superporous chitosan sponge outperforms commercial gauze, gelatin sponges, and chitosan powder by enhancing hemostatic efficiency, cell infiltration, vascular regeneration, and in-situ tissue regeneration in non-compressible organ injury models, respectively. We believe the proposed secondary network compaction strategy provides a simple yet effective method to fabricate superporous hemostatic sponges for diverse clinical applications.

Molecular Pathways Governing the Termination of Liver Regeneration

The liver has the unique capacity to regenerate, and up to 70% of the liver can be removed without detrimental consequences to the organism. Liver regeneration is a complex process involving multiple signaling networks and organs. Liver regeneration proceeds through three phases: the initiation phase, the growth phase, and the termination phase. Termination of liver regeneration occurs when the liver reaches a liver-to-body weight that is required for homeostasis, the so-called "hepatostat." The initiation and growth phases have been the subject of many studies. The molecular pathways that govern the termination phase, however, remain to be fully elucidated. This review summarizes the pathways and molecules that signal the cessation of liver regrowth after partial hepatectomy and answers the question, "What factors drive the hepatostat?" SIGNIFICANCE STATEMENT: Unraveling the pathways underlying the cessation of liver regeneration enables the identification of druggable targets that will allow us to gain pharmacological control over liver regeneration. For these purposes, it would be useful to understand why the regenerative capacity of the liver is hampered under certain pathological circumstances so as to artificially modulate the regenerative processes (e.g., by blocking the cessation pathways) to improve clinical outcomes and safeguard the patient's life.

Preoperative albumin-bilirubin score and liver resection percentage determine postoperative liver regeneration after partial hepatectomy

BACKGROUND

The success of liver resection relies on the ability of the remnant liver to regenerate. Most of the knowledge regarding the pathophysiological basis of liver regeneration comes from rodent studies, and data on humans are scarce. Additionally, there is limited knowledge about the preoperative factors that influence postoperative regeneration.

AIM

To quantify postoperative remnant liver volume by the latest volumetric software and investigate perioperative factors that affect posthepatectomy liver regeneration.

METHODS

A total of 268 patients who received partial hepatectomy were enrolled. Patients were grouped into right hepatectomy/trisegmentectomy (RH/Tri), left hepatectomy (LH), segmentectomy (Seg), and subsegmentectomy/nonanatomical hepatectomy (Sub/Non) groups. The regeneration index (RI) and late regeneration rate were defined as (postoperative liver volume)/[total functional liver volume (TFLV)] × 100 and (RI at 6-months - RI at 3-months)/RI at 6-months, respectively. The lower 25th percentile of RI and the higher 25th percentile of late regeneration rate in each group were defined as "low regeneration" and "delayed regeneration". "Restoration to the original size" was defined as regeneration of the liver volume by more than 90% of the TFLV at 12 months postsurgery.

RESULTS

The numbers of patients in the RH/Tri, LH, Seg, and Sub/Non groups were 41, 53, 99 and 75, respectively. The RI plateaued at 3 months in the LH, Seg, and Sub/Non groups, whereas the RI increased until 12 months in the RH/Tri group. According to our multivariate analysis, the preoperative albumin-bilirubin (ALBI) score was an independent factor for low regeneration at 3 months [odds ratio (OR) 95%CI = 2.80 (1.17-6.69), P = 0.02; per 1.0 up] and 12 months [OR = 2.27 (1.01-5.09), P = 0.04; per 1.0 up]. Multivariate analysis revealed that only liver resection percentage [OR = 1.03 (1.00-1.05), P = 0.04] was associated with delayed regeneration. Furthermore, multivariate analysis demonstrated that the preoperative ALBI score [OR = 2.63 (1.00-1.05), P = 0.02; per 1.0 up] and liver resection percentage [OR = 1.02 (1.00-1.05), P = 0.04; per 1.0 up] were found to be independent risk factors associated with volume restoration failure.

CONCLUSION

Liver regeneration posthepatectomy was determined by the resection percentage and preoperative ALBI score. This knowledge helps surgeons decide the timing and type of rehepatectomy for recurrent cases.

Zinc supports liver regeneration after partial resection

Objectives

Safe removal of extensive liver tumor burdens depends on regeneration of the remnant liver, which requires a large amount of zinc over a short period of time. We studied how zinc influences regeneration.

Material and Methods

We measured perioperative serum zinc concentrations after liver cancer diagnosis in 77 patients undergoing hepatectomy to determine how serum zinc affected short-term outcomes and remnant liver regeneration.

Results

Serum zinc concentration at diagnosis showed no correlation with inflammatory or nutritional parameters except for a weak correlation with the lymphocyte-to-monocyte ratio. When patients were divided into a high pre-hepatectomy zinc group (≥75 µg/dL, n= 39, H group) and a low zinc group (<75 µg/dL, n= 38, L group), short-term results such as mortality (p> 0.999), morbidity (p= 0.490), and hospital stay (p= 0.591) did not differ between groups. However, hypertrophy in the future liver remnant after hepatectomy in the H group (127.7 ± 24.7% of original volume) was greater than in the L group (115.9 ± 16.7%, p= 0.024). In a subgroup of patients with extended hepatectomy, hypertrophy was 130.9 ± 26.8% in the H group vs. 116.4 ± 16.5% in the L group (p= 0.037).

Conclusion

Greater serum zinc at diagnosis was associated with greater hypertrophy in the future liver remnant.

Scientific Hepatectomy for Hepatocellular Carcinoma

With advances in imaging technology and surgical instruments, hepatectomy can be perfectly performed with technical precision for hepatocellular carcinoma (HCC). However, the 5-year tumor recurrence rates remain greater than 70%. Thus, the strategy for hepatectomy needs to be reappraised based on insights of scientific advances. Scientific evidence has suggested that the main causes of recurrence after hepatectomy for HCC are mainly related to underlying cirrhosis and the vascular spread of tumor cells that basically cannot be eradicated by hepatectomy. Liver transplantation and systemic therapy could be the solution to prevent postoperative recurrence in this regard. Therefore, determining the severity of liver cirrhosis for choosing the appropriate surgical modality, such as liver transplantation or hepatectomy, for HCC and integrating newly emerging immune-related adjuvant and/or neoadjuvant therapy into the strategy of hepatectomy for HCC have become new aspects of exploration to optimize the strategy of hepatectomy. In this new area, hepatectomy for HCC has evolved from a pure technical concept emphasizing anatomic resection into a scientific concept embracing technical considerations and scientific advances in underlying liver cirrhosis, vascular invasion, and systemic therapy. By introducing the concept of scientific hepatectomy, the indications, timing, and surgical techniques of hepatectomy will be further scientifically optimized for individual patients, and recurrence rates will be decreased and long-term survival will be further prolonged.

Aberrant regulation of autophagy disturbs fibrotic liver regeneration after partial hepatectomy

Reports indicate that autophagy is essential for maintaining hepatocyte proliferative capacity during liver regeneration. However, the role of autophagy in fibrotic liver regeneration is incompletely elucidated. We investigated the deregulation of autophagic activities in liver regeneration after partial hepatectomy using a CCl4-induced fibrosis mouse model. The baseline autophagic activity was significantly increased in the fibrotic liver. After 50% partial hepatectomy (PHx), liver regeneration was remarkably decreased, accompanied by increased hepatocyte size and binuclearity ratio. Moreover, the expression of autophagy-related proteins was functionally deregulated and resulted in a reduction in the number of autophagosome and autophagosome-lysosome fusions. We further showed upregulation of autophagy activities through verapamil administration, improved hepatocyte proliferation capacity, and restricted cellular hypertrophy and binuclearity ratio. In conclusion, we demonstrated that the impairment of liver regeneration is associated with aberrant autophagy in fibrotic liver and that enhancing autophagy with verapamil may partially restore the impaired liver regeneration following PHx.

Impact of laparoscopic liver resection on liver regeneration

BACKGROUND

Liver regeneration after liver resection plays an important role in preventing posthepatectomy liver failure. In this study, we aimed to evaluate and compare the impact of laparoscopic liver resection (LLR) and open liver resection (OLR) on liver regeneration.

METHODS

Patients who underwent curative anatomical liver resection for hepatocellular carcinoma, cholangiocellular carcinoma, and colorectal liver metastases at our institution between January 2010 and December 2018 were included in this study. The patients were divided into the OLR and LLR groups. Preoperative liver volume (PLV), future remnant liver volume, resected liver volume (RLV), liver volume at 1 month after the surgery, and liver volume at 6 months after the surgery were calculated. The liver regeneration rate was defined as the increase in the rate of RLV, and the liver recovery rate was defined as the rate of return to the PLV.

RESULTS

The study included 72 patients. Among them, 43 were included in the OLR group and 29 were included in the LLR group. No differences were observed in the baseline characteristics and surgical procedures between the two groups. Moreover, no significant difference was observed in the liver regeneration rate at 1 month after the surgery (OLR vs. LLR: 68.9% vs. 69.0%, p = 0.875) and at 6 months after the surgery (91.8% vs. 93.2%, p = 0.995). Furthermore, the liver recovery rates were not significantly different between the two groups at 1 month after the surgery (90.3% vs. 90.6%, p = 0.893) and at 6 months after the surgery (96.9% vs. 98.8%, p = 0.986).

CONCLUSION

Liver regeneration after liver resection is not affected by the type of surgical procedure and both laparoscopic and open procedures yield similar regeneration and recovery rates.

Assessment of Fibrotic Liver Regeneration After Partial Hepatectomy With Intravoxel Incoherent Motion Diffusion-Weighted Imaging: An Experimental Study in a Rat Model With Carbon Tetrachloride Induced Liver Injury

Purpose

To determine whether intravoxel incoherent motion (IVIM) parameters correlate with liver regeneration and function recovery after partial hepatectomy (PH) in rats with carbon tetrachloride (CCl₄)-induced liver fibrosis.

Methods

Sixty-two adult Sprague-Dawley rats were divided into the control group and the fibrosis group with CCl₄ injection for 8 weeks. At the end of the 8th week, all rats received left lateral lobe liver resection. Within each group, IVIM imaging (n = 10/group) and histologic and biochemical analyses (n = 3/group/time point) were performed pre- and post-PH (on days 1, 2, 3, 5, 7, 14, and 21). Differences in liver IVIM parameters and correlation between IVIM parameters and Ki-67 indices, hepatocyte diameter, alanine transaminase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBil) values were analyzed.

Results

Post-PH, liver true diffusion coefficient (D) values decreased and pseudodiffusion coefficient (D*) and perfusion fraction (PF) values increased, then recovered to pre-PH levels gradually in both fibrosis and control rats. PF in fibrosis group were significantly higher than in controls from 3 to 21 days (P < 0.05). In fibrosis rats, both Ki-67 indices and hepatocyte diameters increased, and a strong correlation was found between PF and Ki-67 indices (r = −0.756; P = 0.03), D* and PF values and ALT, AST, and TBil values (r = −0.762 to −0.905; P < 0.05). In control rats, only hepatocyte diameters increased, and all IVIM parameters correlated well with hepatocyte diameters, ALT, AST and TBil values (r = 0.810 to −1.000; P < 0.05).

Conclusion

The regeneration pattern in fibrotic liver tissue was different compared with control livers. IVIM parameters can monitor liver regeneration and functional recovery non-invasively after PH.

Genetic and Cellular Contributions to Liver Regeneration

The regenerative capabilities of the liver represent a paradigm for understanding tissue repair in solid organs. Regeneration after partial hepatectomy in rodent models is well understood, while regeneration in the context of clinically relevant chronic injuries is less studied. Given the growing incidence of fatty liver disease, cirrhosis, and liver cancer, interest in liver regeneration is increasing. Here, we will review the principles, genetics, and cell biology underlying liver regeneration, as well as new approaches being used to study heterogeneity in liver tissue maintenance and repair.

State-of-the-art surgery for hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the most commonly diagnosed primary liver tumor with an increasing incidence worldwide. Management of patients with HCC is largely dictated by the presence of cirrhosis, disease stage, underlying liver function, and patient performance status.

PURPOSE

We provide an update on key aspects of surgical treatment options for patients with HCC. RESULTS & CONCLUSIONS: Liver resection and transplantation remain cornerstone treatment options for patients with early-stage disease and constitute the only potentially curative options for HCC. Selection of patients for surgical treatment should include a thorough evaluation of tumor characteristics and biology, as well as evidence-based use of various available treatment options to achieve optimal long-term outcomes for patients with HCC.

The hippo pathway: A master regulator of liver metabolism, regeneration, and disease

The liver is the only visceral organ in the body with a tremendous capacity to regenerate in response to insults that induce inflammation, cell death, and injury. Liver regeneration is a complicated process involving a well-orchestrated activation of non-parenchymal cells in the injured area and proliferation of undamaged hepatocytes. Furthermore, the liver has a Hepatostat, defined as adjustment of its volume to that required for homeostasis. Understanding the mechanisms that control different steps of liver regeneration is critical to informing therapies for liver repair, to help patients with liver disease. The Hippo signaling pathway is well known for playing an essential role in the control and regulation of liver size, regeneration, stem cell self-renewal, and liver cancer. Thus, the Hippo pathway regulates dynamic cell fates in liver, and in absence of its downstream effectors YAP and TAZ, liver regeneration is severely impaired, and the proliferative expansion of liver cells blocked. We will mainly review upstream mechanisms activating the Hippo signaling pathway following partial hepatectomy in mouse model and patients, its roles during different steps of liver regeneration, metabolism, and cancer. We will also discuss how targeting the Hippo signaling cascade might improve liver regeneration and suppress liver tumorigenesis.

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) in colorectal liver metastases: review of the literature

The liver is considered as one of the most common sites of metastasis and a key determining factor of survival in patients with isolated colorectal liver metastasis (CRLM). For longer survival of patients, surgical resection is the only available option. Especially in CRLM bilobar patients, to achieve R0 resection, maintaining an adequate volume of the future liver remnant (FLR) is the main technical challenge to avoid post-hepatectomy liver failure (PHLF). As standard procedures in the treatment of patients with severe metastatic liver disease, techniques such as portal vein embolization/portal vein ligation (PVE/PVL) accompanied by two-stage hepatectomy (TSH) have been introduced. These methods, however, have drawbacks depending on the severity of the disease and the capacity of the patient to expand the liver remnant. Eventually, implementation of the novel ALPPS technique ignited excitement among the community of hepatobiliary surgeons because ALPPS challenged the idea of unrespectability and extended the limit of liver surgery and it was reported that FLR hypertrophy of up to 80% was induced in a shorter time than PVL or PVE. Nonetheless, ALPPS techniques caused serious concerns due to the associated high morbidity and mortality levels of up to 40% and 15% respectively, and PHLF and bile leak are critical morbidity- and mortality-related factors. Carefully establishing the associated risk factors of ALPPS has opened up a new dimension in the field of ALPPS technique for improved surgical outcome by carefully choosing patients. The benefit of ALPPS technique is enhanced when performed for young patients with very borderline remnant volume. Adopting ALPPS technical modifications such as middle hepatic vein preservation, surgical management of the hepatoduodenal ligament, the anterior approach and partial ALPPS may lead to the improvement of ALPPS surgical performance. Research findings to validate the translatability of ALPPS’ theoretical advantages into real survival benefits are scarce.

Adult split liver transplantation: A PRISMA-compliant Chinese single-center retrospective case-control study

Although pediatric split liver transplantation (SLT) has been proven safe and the waitlist mortality rate has been successfully reduced, the safety of adult SLT has not been confirmed.Using 1:2 matching, 47 recipients who underwent adult SLT were matched to 94 of 743 recipients who underwent adult whole graft liver transplantation (WGLT). Eventually, 141 recipients were included in the case-control study. Subgroup analysis of 43 recipients in the SLT group was performed based on the presence of the middle hepatic vein (MHV) in the grafts.No significant differences in 5-year survival (80.8% vs 81.6%, P = .465) were observed between the adult SLT and WGLT groups. However, compared to recipients in the WGLT group, those in the SLT group had more Clavien-Dindo grade III-V complications, longer hospitalization duration, and higher mortality within 45 days. Furthermore, on multivariate analysis, 45-day postoperative mortality in recipients in the SLT group was mainly affected by hyperbilirubinemia within postoperative day (POD) 7-14, surgery time, and intraoperative blood loss. Subgroup analysis showed no significant differences in hyperbilirubinemia within POD 7-14, complications, and survival rate between SLTMHV(+) and SLTMHV [-].Adult SLT is safe and effective based on long-term survival rates; however, a reduction in the incidence of short-term complications is required. Non-obstructive hyperbilirubinemia within POD 7 to 14 is an independent predictor of short-term mortality after SLT.

Preoperative noninvasive assessment for liver fibrosis in hepatocellular carcinoma patients with chronic hepatitis B: Comparison of two-dimensional shear-wave elastography with serum liver fibrosis models

PURPOSE

To investigate the diagnostic performance of two-dimensional shear-wave elastography (2D-SWE) in hepatocellular carcinoma patients with chronic hepatitis B adapted to hepatectomy comparing to serum liver fibrosis models.

METHOD

100 patients with chronic hepatitis B who first diagnosed with hepatocellular carcinoma and had undergone 2D-SWE measurements before the hepatectomy were included. The performance of 2D-SWE and serum models in the diagnosis of liver fibrosis was assessed using receiver operating characteristic (ROC) analyses.

RESULTS

The areas under ROC (AUCs) for 2D-SWE, Forns score, aspartate transaminase-to-platelet ratio index (APRI) and Fibrosis 4 Score (FIB-4) were 0.983, 0.757, 0.745, 0.710 in the diagnosis of significant fibrosis (F ≥ 2) respectively, and 0.896, 0.718, 0.626, 0.575 in the diagnosis of cirrhosis (F = 4) respectively. The AUCs for 2D-SWE in the diagnosis of significant fibrosis and cirrhosis were significantly higher than those for the serum fibrosis models (p < 0.05). The AUCs of Forns in the diagnosis of significant fibrosis (F ≥ 2) showed no statistical differences (p > 0.05) with those of APRI and FIB-4 while in the diagnosis of cirrhosis (F = 4), they are significantly higher (p < 0.05).

CONCLUSIONS

2D-SWE is a reliable method for preoperative noninvasive assessment of liver fibrosis in HCC patients with CHB, with notably higher diagnostic accuracy than serum liver fibrosis models.

Prediction of liver regeneration in recipients after living-donor liver transplantation in using preoperative CT texture analysis and clinical features

PURPOSE

The aim of the study is to predict the rate of liver regeneration in recipients after living-donor liver transplantation using preoperative CT texture and shape analysis of the future graft.

METHODS

102 donor-recipient pairs who underwent living-donor liver transplantation using right lobe grafts were retrospectively included. We semi-automatically segmented the future graft from preoperative CT. The volume of the future graft (LV_pre) was measured, and texture and shape analyses were performed. The graft liver was segmented from postoperative follow-up CT and the volume of the graft (LV_post) was measured. The regeneration index was defined by the following equation: [(LV_post-LV_pre)/LV_pre] × 100(%). We performed a stepwise, multivariate linear regression analysis to investigate the association between clinical, texture and shape parameters and the RI and to make the best-fit predictive model.

RESULTS

The mean regeneration index was 47.5 ± 38.6%. In univariate analysis, the volume of the future graft, energy, effective diameter, surface area, sphericity, roundness_m, compactness1, and grey-level co-occurrence matrix contrast as well as several clinical parameters were significantly associated with the regeneration index (p < 0.05). The best-fit predictive model for the regeneration index made by multivariate analysis was as follows: Regeneration index (%) = 127.020-0.367 × effective diameter - 1.827 × roundness_m + 47.371 × recipient body surface area (m²) + 12.041 × log(recipient white blood cell count) (× 10³/μL)+ 18.034 (if the donor was female).

CONCLUSION

The effective diameter and roundness_m of the future graft were associated with liver regeneration. Preoperative CT texture analysis of future grafts can be useful for predicting liver regeneration in recipients after living-donor liver transplantation.

Controversies Surrounding the Origin of Hepatocytes in Adult Livers and the in Vitro Generation or Propagation of Hepatocytes

Epithelial cells in the liver (known as hepatocytes) are high-performance engines of myriad metabolic functions and versatile responders to liver injury. As hepatocytes metabolize amino acids, alcohol, drugs, and other substrates, they produce and are exposed to a milieu of toxins and harmful byproducts that can damage themselves. In the healthy liver, hepatocytes generally divide slowly. However, after liver injury, hepatocytes can ramp up proliferation to regenerate the liver. Yet, on extensive injury, regeneration falters, and liver failure ensues. It is therefore critical to understand the mechanisms underlying liver regeneration and, in particular, which liver cells are mobilized during liver maintenance and repair. Controversies continue to surround the very existence of hepatic stem cells and, if they exist, their spatial location, multipotency, degree of contribution to regeneration, ploidy, and susceptibility to tumorigenesis. This review discusses these controversies. Finally, we highlight how insights into hepatocyte regeneration and biology in vivo can inform in vitro studies to propagate primary hepatocytes with liver regeneration-associated signals and to generate hepatocytes de novo from pluripotent stem cells.

Issues to be considered to address the future liver remnant prior to major hepatectomy

An accurate preoperative evaluation of the hepatic function and application of portal vein embolization in selected patients have helped improve the safety of major hepatectomy. In planning major hepatectomy, however, several issues remain to be addressed. The first is which cut-off values for serum total bilirubin level and prothrombin time should be used to define post-hepatectomy liver failure. Other issues include what minimum future liver remnant (FLR) volume is required; whether the total liver volume measured using computed tomography or the standard liver volume calculated based on the body surface area should be used to assess the adequacy of the FLR volume; whether there is a discrepancy between the FLR volume and function during the recovery period after portal vein embolization or hepatectomy; and how best the function of a specific FLR can be assessed. Various studies concerning these issues have been reported with controversial results. We should also be aware that different strategies and management are required for different types of liver damage, such as cirrhosis in hepatocellular carcinoma, cholangitis in biliary tract cancer, and chemotherapy-induced hepatic injury.

Splenic enlargement induced by preoperative chemotherapy is a useful indicator for predicting liver regeneration after resection for colorectal liver metastases

Background

Conversion chemotherapy may downsize unresectable colorectal liver metastases (CRLMs), but may cause liver injury and splenic enlargement. The effect of preoperative chemotherapy on liver regeneration after liver resection remains undetermined. The aim of this study was to examine whether splenic enlargement induced by preoperative chemotherapy is an indicator to identify high-risk patients for impaired liver regeneration and liver dysfunction after resection.

Methods

We retrospectively reviewed 118 Japanese patients with CRLMs. Fifty-one patients had conversion chemotherapy. The other 67 patients underwent up-front liver resection. We clarified effects of conversion chemotherapy on splenic volume, liver function, and postoperative liver regeneration. Perioperative outcome was also analyzed.

Results

A ratio of the splenic volume before and after chemotherapy (SP index) in the oxaliplatin-based chemotherapy group was significantly greater than other chemotherapy groups after 9 or more chemotherapy cycles. Patients whose SP index was 1.2 or more had significantly higher indocyanine green retention rate at 15 min (ICG-R15) than patients without chemotherapy. Analyses of covariance showed liver regeneration rate after resection was decreased in patients whose SP index was 1.2 or more. The incidence of postoperative liver dysfunction in patients whose SP index was 1.2 or more was significantly greater than patients without chemotherapy. Multivariate analysis showed SP index was a significant predictive factor of impaired liver regeneration.

Conclusions

Splenic enlargement induced by preoperative chemotherapy was a useful indicator for impaired liver regeneration after resection and a decision-making tool of treatment strategy for unresectable CRLMs.

Characteristic Risk Factors in Cirrhotic Patients for Posthepatectomy Complications: Comparison with Noncirrhotic Patients

There seemed to be characteristic risk factors in cirrhotic patients for posthepatectomy complications because these patients have less hepatic reserve as compared with noncirrhotic patients. The aim of the current study was to identify these characteristic risk factors in cirrhotic patients. We performed 419 primary hepatectomies for hepatocellular carcinoma. The patients were divided into the cirrhotic group (n = 198) and the noncirrhotic group (n = 221), and the risk factors for posthepatectomy complications were compared between the groups. Thirty-six cirrhotic patients (18.2%) experienced Clavien's Grade III or more complications. Tumor size, intraoperative blood loss, duration of operation, major hepatectomy (two or more segments), and necessity of blood transfusion were found to be significant risk factors in univariate analyses. Multivariate analysis revealed that major hepatectomy and intraoperative blood loss were independent risk factors for posthepatectomy complications in patients with cirrhosis. On the other hand, the duration of operation was only an independent risk factor for posthepatectomy complication in noncirrhotic patients. Cirrhotic patients should avoid a major hepatectomy and undergo a limited resection preserving as much liver tissue as possible and meticulous surgical procedures to lessen intraoperative blood loss are mandatory to prevent major posthepatectomy complications.

Liver fibrosis is a major risk factor for liver regeneration: A comparison between healthy and fibrotic liver

BACKGROUND

Blood flow factors, such as congestion or ischemia after hepatectomy, have a significant impact on liver regeneration, but with the popularization of precise hepatectomy technology, segmental hepatectomy without congestion or ischemia has become the preferred treatment. Our aim is to investigate the factors affecting liver regeneration after hepatectomy without blood flow changes, and to provide clinical evidence for surgeons on the timing of second hepatectomy for cirrhosis patients with hepatocellular carcinoma (HCC).

METHODS

This study retrospectively analyzed data from patients who underwent right hepatectomy without middle hepatic vein (MHV) in West China Hospital between January 2016 and January 2018. Eighteen living-donors without MHV as normal group and 45 HCC patients, further classified into 3 subgroups based on the severity of fibrosis using the Scheure system. Demographic data, pre- and postoperative liver function indexes, and remnant liver volume (RLV) were retrospectively compared. We also analyzed the remnant liver regeneration rate (RLRR) post-operatively in each group. The significant indexes in univariate analysis were further analyzed using both receiver operating characteristic (ROC) analysis and multivariate regression analysis.

RESULTS

Liver regeneration occurred in both living-donor and HCC groups after hepatectomy; the RLRRs at 1 month were 59.46 ± 10.39% and 57.27 ± 4.77% (P = .509), respectively. Regeneration in the cirrhosis group occurred more slowly and less completely compared with that in other groups. The regeneration rate in the first 6 months showed rapid increase and the RLRR reached above 70% in cirrhosis group. Multivariate and ROC analyses revealed that Alb and the hepatic fibrosis grade in the early postoperative period were significant predictors of remnant liver regeneration.

CONCLUSION

The liver regenerated in all HCC patients; however, regeneration was significantly slower and less complete compared with the normal liver, especially in the patients with cirrhosis. Therefore, it can be concluded that the degree of liver fibrosis is a major predictor of liver regeneration. Furthermore, the optimal time for second resection in recurrent HCC patients with cirrhosis was 6 months after the first operation.

Long-term impact and clinical significance of living donor liver transplantation with respect to donor liver restoration and spleen size: A prospective study

This study aimed to evaluate postoperative long-term liver restoration and splenic enlargement and their clinical significance in living donor liver transplantation. One hundred and sixteen donors who had donated livers more than 5 years previously accepted the invitation to participate in this study. The liver restoration rate and the splenic enlargement rate were calculated as the rate with respect to the original volume. The mean liver restoration rate was 0.99 ± 0.12 and older age was associated with a higher incidence for liver restoration rate <0.95 (P = .005), whereas type of donor operation was not. The donors with liver restoration rate <0.95 showed lower serum albumin levels than those with liver restoration rate ≥0.95. The mean splenic enlargement rate was 1.10 ± 0.16. Right lobe donors demonstrated higher splenic enlargement rate (1.14 ± 0.18) than left lobe/lateral segment donors (1.06 ± 0.13). In the donors with splenic enlargement rate ≥1.10, platelet count was not fully restored to the preoperative level. In conclusion, older age increases the risk for incomplete postoperative liver restoration, which may be associated with a decrease in albumin more than 5 years after donation. Right lobe donation poses a risk of splenic enlargement, which is associated with incomplete restoration of platelet count.

Markers of liver regeneration-the role of growth factors and cytokines: a systematic review

BACKGROUND

Post-hepatectomy liver failure contributes significantly to postoperative mortality after liver resection. The prediction of the individual risk for liver failure is challenging. This review aimed to provide an overview of cytokine and growth factor triggered signaling pathways involved in liver regeneration after resection.

METHODS

MEDLINE and Cochrane databases were searched without language restrictions for articles from the time of inception of the databases till March 2019. All studies with comparative data on the effect of cytokines and growth factors on liver regeneration in animals and humans were included.

RESULTS

Overall 3.353 articles comprising 40 studies involving 1.498 patients and 101 animal studies were identified and met the inclusion criteria. All included trials on humans were retrospective cohort/observational studies. There was substantial heterogeneity across all included studies with respect to the analyzed cytokines and growth factors and the described endpoints.

CONCLUSION

High-level evidence on serial measurements of growth factors and cytokines in blood samples used to predict liver regeneration after resection is still lacking. To address the heterogeneity of patients and potential markers, high throughput serial analyses may offer a method to predict an individual's regenerative potential in the future.

Repeated CyberKnife stereotactic body radiation therapy in hepatocellular carcinoma

Background

To explore the survival and side effects of repeated CyberKnife stereotactic body radiation therapy (CK-SBRT) on hepatocellular carcinoma patients.

Methods

24 HCC patients were collected at The Fifth Medical Center of PLA General Hospital from November 2011 to July 2016. They received second-course CK-SBRT with a prescribed dose of 50(48–55) Gy/5-8fx, and a single dose of 10 (7–11) Gy/fx. Cumulative overall survival rates (OS), progression-free survival rates (PFS) and local control rates (LC) were calculated by Kaplan-Meier method.

Results

All patients finished their radiotherapy plans. The 1-,2- and 3-year cumulative OS rate were 95.8,81.1 and 60.8%. The 1-,2- and 3-year LC rate were 95.5,90.7 and 90.7%, respectively. The 1-, 2- and 3-year PFS were 74.8, 49.2 and 39.4%, respectively. 16 patients complained of fatigue during second-course therapy, 2 patients showed Grade 2 gastrointestinal reaction, 1 patient was diagnosed radiation-induced liver disease and none died. PFS was significantly higher in the interval time < 12 months group than in the interval time ≥ 12 months group (p = 0.030).

Conclusions

It is preliminarily believed that re-CK-SBRT is an effective and safe treatment for HCC patients, but the treatment criteria should be strictly controlled.

Serum Levels of Granulocyte-Macrophage-colony-stimulating Factor and Stem-cell Factor During Liver Regeneration after Partial Hepatectomy in Humans

BACKGROUND

Multiple biological functions have been recognized regarding Granulocyte Macrophage-Colony Stimulating Factor (GM-CSF) and Stem Cell Factor (SCF).

AIM

To evaluate the serum changes of GM-CSF and SCF in patients undergoing surgical resection for liver tumor, in the regenerative phase after surgery in order to identify the possible relationship with the patient, tumor or surgical variables.

METHODS

Thirty-two consecutive patients (50% male, median age 66), undergoing hepatic resection of liver neoplasm, were evaluated. The liver tumor was Hepatocellular Carcinoma (HCC) in 44% of cases. Other tumors were cholangiocarcinoma and metastasis. Serum levels of GM-CSF and SCF were assessed at baseline and 2 days, 7 days and 4 weeks after surgery. Personal and clinical patient data were also recorded. The statistical analysis was carried out using t-test for unpaired data or ANOVA (repeated measure) for continuous variables and Fisher test for discrete variables.

RESULTS

GM-CSF levels remained constant after surgery and were compared to baseline values. SCF levels, on the other hand, increased during the time, after surgery. The evaluation of SCF levels (fold increase) according to surgical, patient and tumor variables evidenced some differences. At day 7 and week 4, SCF levels were statistically increased: i) in patients undergoing a large resection in comparison with others (p<0.05); ii) in patients non-cirrhotic in comparison with cirrhotic ones (p=0.02) and finally; iii) in patients with non-HCC tumor in comparison with HCC ones (p=0.02).

CONCLUSION

During liver regeneration in humans, SCF serum levels are increased allowing to hypothesize a possible role of this chemokine during tissue growth and remodeling.

Current status of associating liver partition with portal vein ligation for staged hepatectomy: Comparison with two-stage hepatectomy and strategies for better outcomes

Since its introduction in 2012, associating liver partition with portal vein ligation for staged hepatectomy (ALPPS) has significantly expanded the pool of candidates for liver resection. It offers patients with insufficient liver function a chance of a cure. ALPPS is most controversial when its high morbidity and mortality is concerned. Operative mortality is usually a result of post-hepatectomy liver failure and can be minimized with careful patient selection. Elderly patients have limited reserve for tolerating the demanding operation. Patients with colorectal liver metastasis have normal liver and are ideal candidates. ALPPS for cholangiocarcinoma is technically challenging and associated with fair outcomes. Patients with hepatocellular carcinoma have chronic liver disease and limited parenchymal hypertrophy. However, in selected patients with limited hepatic fibrosis satisfactory outcomes have been produced. During the inter-stage period, serum bilirubin and creatinine level and presence of surgical complication predict mortality after stage II. Kinetic growth rate and hepatobiliary scintigraphy also guide the decision whether to postpone or omit stage II surgery. The outcomes of ALPPS have been improved by a combination of technical modifications. In patients with challenging anatomy, partial ALPPS potentially reduces morbidity, but remnant hypertrophy may compare unfavorably to a complete split. When compared to conventional two-stage hepatectomy with portal vein embolization or portal vein ligation, ALPPS offers a higher resection rate for colorectal liver metastasis without increased morbidity or mortality. While ALPPS has obvious theoretical oncological advantages over two-stage hepatectomy, the long-term outcomes are yet to be determined.

Evidence for lung repair and regeneration in humans: key stem cells and therapeutic functions of fibroblast growth factors

Regeneration carries the idea of regrowing partially or completely a missing organ. Repair, on the other hand, allows restoring the function of an existing but failing organ. The recognition that human lungs can both repair and regenerate is quite novel, the concept has not been widely used to treat patients. We present evidence that the human adult lung does repair and regenerate and introduce different ways to harness this power. Various types of lung stem cells are capable of proliferating and differentiating upon injury driving the repair/regeneration process. Injury models, primarily in mice, combined with lineage tracing studies, have allowed the identification of these important cells. Some of these cells, such as basal cells, broncho-alveolar stem cells, and alveolar type 2 cells, rely on fibroblast growth factor (FGF) signaling for their survival, proliferation and/or differentiation. While preclinical studies have shown the therapeutic benefits of FGFs, a recent clinical trial for acute respiratory distress syndrome (ARDS) using intravenous injection of FGF7 did not report the expected beneficial effects. We discuss the potential reasons for these negative results and propose the rationale for new approaches for future clinical trials, such as delivery of FGFs to the damaged lungs through efficient inhalation systems, which may be more promising than systemic exposure to FGFs. While this change in the administration route presents a challenge, the therapeutic promises displayed by FGFs are worth the effort.

Ischemic complications after percutaneous radiofrequency ablation of liver tumors: Liver volume loss and recovery

AIM

The liver regrows after acute liver injury and liver resection. However, it is not clear whether the liver regenerates in advanced cirrhosis. This study aimed to evaluate the clinical course of, and liver volume change after, ischemic liver complications caused by radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC).

METHODS

We enrolled 35 patients with ischemic complications after RFA. Ischemic complications were defined as rapid elevation of aspartate aminotransferase (AST) to over 500 U/L, with typical radiological findings. Patient characteristics and the ischemic liver volume were investigated. Long-term liver volume changes at 3-8 months after ischemic complications were also assessed in 32 patients. We also assessed the overall survival rate after ischemic complications.

RESULTS

The median value of peak AST was 798 U/L (range, 531-4096 U/L). The median ischemic liver volume relative to the functional liver volume before RFA was 13% (range, 3.1-46.5%). There was a strong correlation between the peak AST value and the ischemic liver volume (r = 0.84, P < 0.001). The liver volume recovered to some extent in 18 of 32 (56%) patients after ischemic complications. The survival rate after ischemic complications was 45.7% at 5 years and correlated with the functional liver volume after ischemic complications (P = 0.02).

CONCLUSIONS

Ischemic complications after RFA can lead to massive liver parenchymal loss. Although the liver volume recovered to some extent in the majority of our patients, ischemic liver complications after RFA should be avoided to improve the overall survival rate.

Evaluation of interleukin-6 concentration in the liver of Albino Swiss mice after intoxication with various doses of patulin

Patulin is a mycotoxin produced by many species of the fungi. The toxic action of patulin mainly affects the gastrointestinal tract and the immune system. The aim of our work was to assess the toxic effect of patulin, based on the analysis of interleukin IL-6 concentrations in the liver of test animals loaded with different doses of this mycotoxin. The research was conducted on mice which were assigned to 6 groups receiving different doses of active substances. After decapitation, their livers were taken for laboratory testing.

Our studies have shown that chronic intoxication with patulin at 0.1 LD50 leads to a statistically significant increase in IL-6 concentration in the liver of the animals. We also found that the loading of experimental animals with a single dose of patulin in the amount of 0.5 LD50 and 0.2 LD50 also leads to a statistically significant increase in this interleukin in the examined organ. There was no difference in its concentration compared to the control group only after the single dose of the lowest concentration of patulin, while the highest average IL-6 concentration was recorded in the liver of animals loaded with the highest single dose of patulin. After applying, one-time doses of this mycotoxin in the amount of 0.2 LD50 and 0.1 LD50, the mean concentrations of IL-6 in the liver in animals from these groups were statistically significantly lower.

In conclusion, the analysis of the obtained results confirms the fact of the hepatotoxic effect of patulin.

Multiple factors affect the regeneration of liver

OBJECTIVE

To study factors affecting the liver regeneration after hepatectomy.

METHODS

With 3D reconstitution technology, liver regeneration ability of 117 patients was analysed, and relative factors were studied.

RESULTS

There was no statistically difference between the volume of simulated liver resection and the actual liver resection. All livers had different degrees of regeneration after surgery. Age, gender and blood indicators had no impact on liver regeneration, while surgery time, intraoperative blood loss, blood flow blocking time and different ways of liver resection had a significant impact on liver regeneration; In addition, the patients' own pathological status, including, hepatitis and liver fibrosis all had a significant impact on liver regeneration.

CONCLUSION

3D reconstitution model is a good model to calculate liver volume. Age, gender, blood indicators and biochemistry indicators have no impact on liver regeneration, but surgery indicators and patients' own pathological status have influence on liver regeneration.

Intraoperative liver steatosis characterization using diffuse reflectance spectroscopy

BACKGROUND

Liver steatosis is associated with poor outcome after liver transplantation and liver resection. There is a need for an accurate and reliable intraoperative tool to identify and quantify steatosis. This study aimed to investigate whether surface diffuse reflectance spectroscopy (DRS) measurements could detect liver steatosis on humans during liver surgery.

METHODS

The DRS instrumentation setup consists of a computer, a high-power tungsten halogen light source and two spectrometers, connected through a trifurcated optical fiber to a hand-held probe. Patients scheduled for open resection for liver tumors were considered for inclusion. Multiple DRS measurements were performed on the liver surface after mobilization.

RESULTS

In total, 1210 DRS spectra originated from 38 patients, were analyzed. When applying the data to an analytical model the volumetric absorption ratio factor of fat and water specified an explicit distinction between mild to moderate, and moderate to severe steatosis (p < 0.001). There were significant differences between none-to-mild and moderate-to-severe steatosis grade for the following parameters: reduced scattering coefficient (p < 0.001), Mie to total scattering fraction (p < 0.001), Mie slope (p = 0.003), lipid/(lipid + water) (p < 0.001), blood volume (p = 0.044) and bile volume (p < 0.001).

CONCLUSION

This study shows that it is possible to evaluate steatosis grades with hepatic surface diffuse reflectance spectroscopy measurements.

Liver Regeneration is Preserved After At Least Four Repeated Liver Resections for Hepatocellular Carcinoma

INTRODUCTION

Repeated resection is known to prolong survival, with an acceptable morbidity rate, in patients with hepatocellular carcinoma. However, little is known about the effect of repeated liver resection on postoperative liver regeneration and liver function. The aim of this study is to determine the impact of repeated liver resections on the postoperative liver regeneration rate and liver function.

METHODS

A total of 71 patients, who had undergone more than three liver resections for hepatocellular carcinoma between May 2001 and December 2013 at a tertiary care hospital in Japan, were included in the analysis. Among them, CT-volumetric data for the first, second, third, and fourth or more resections were available for 36, 49, 53, and 24 patients. We analyzed the regeneration index (RI) defined as the postoperative TLV/preoperative TLV × 100 was calculated after each operation to measure the degree of regeneration. Liver function was evaluated using the indocyanine green retention rate at 15 min (ICG-R15).

RESULTS

No significant differences in RI were observed among the first, second, and third or more liver resection groups. No significant difference in the ICG R15 value was seen between the first liver resection group and the second or more liver resection group (P = 0.75). However, a significant difference in the RI was observed when the 1 segmentectomy or less liver resection group (median [range] RI 98.1 [72.9-119.9]) was compared with the 2 or more segmentectomy group (median [range] RI 90.5 [62.6-113.6]) (P = 0.005).

CONCLUSION

The regeneration process is maintained after as many as four repeated resections. Patients with sustained liver function can safely undergo repeated liver resections for recurrences of HCC.

Liver Regeneration After Major Liver Resection for Hepatocellular Carcinoma in the Elderly

Background: With an aging population, more elderly patients are being considered for hepatic resection for hepatocellular carcinoma (HCC). This study aimed to evaluate postoperative outcomes including liver regeneration after major hepatectomy for HCC in the elderly.Methods: We assessed 41 patients who underwent major hepatectomy (≥3 segments) at our institute between 2000 and 2013. Patients were divided into two age groups, elderly group (age ≥70 years, n = 23) and younger group (age <70 years, n = 18). Clinicopathological data and outcomes were retrospectively compared. To evaluate the effect of aging on liver regeneration, we measured liver volumes preoperatively and at 1 and 6 months after liver resection using a 3D simulation imaging system.Results: Overall and major complications after hepatectomy were not different between elderly and younger groups, and no case of mortality was recorded. Moreover, recurrence-free and overall survivals were similar in both groups. With regard to liver regeneration, no differences were observed between elderly and younger groups at 1 and 6 months after liver resection. Baseline liver functions were comparable between the groups. Furthermore, the only factor associated with liver regeneration was resected liver volume (R² = 0.631, p < 0.001). Age was not correlated with liver regeneration rate (R² = 0.00537, p = 0.695).Conclusions: Liver regeneration after major hepatectomy for HCC was not affected by age and that resected liver volume is an important factor for liver regeneration. Short- and long-term outcomes after major hepatectomy were similar in elderly and younger patients.

Preoperative erythropoietin treatment improves survival following major hepatic resection in a cirrhotic rat model

AIM

Major hepatic resection of a cirrhotic liver may result in a fatal clinical course. Preoperative erythropoietin (EPO) treatment has been shown to have protective properties and to stimulate liver regeneration. This study aims to investigate the effect of preoperative EPO on survival following major hepatic resection in a cirrhotic rat model.

METHODS

Cirrhotic liver was induced by intraperitoneal injection of thioacetamide (200mg/kg/mL) in 72 Lewis rats. Each 36 rats received EPO (1IU/g, every second day, 5 times preoperatively) or saline (control) and major hepatectomy (removal of the left and half of the median lobe) was performed. Biochemical and immunohistochemical parameters, cytokines and overall survival were compared following surgery.

RESULTS

Rats that received preoperative EPO had decreased hepatic aspartate aminotransferase, alanine aminotransferase and interleukin (IL)-1β expression, 48hours following surgery. They had increased hepatocyte growth factor and vascular endothelial growth factor expression at 1hour, increased IL-6 expression at 24, 48 and 120hours and increased Ki-67, 120hours following surgery. Overall, survival was significantly improved among EPO-treated rats (P=0.034).

CONCLUSION

Preoperative EPO treatment has a protective effect and stimulates liver regeneration, leading to improved overall survival following major hepatectomy in a cirrhotic rat model.

Modeling the Dynamics of Human Liver Failure Post Liver Resection

Liver resection is an important clinical intervention to treat liver disease. Following liver resection, patients exhibit a wide range of outcomes including normal recovery, suppressed recovery, or liver failure, depending on the regenerative capacity of the remnant liver. The objective of this work is to study the distinct patient outcomes post hepatectomy and determine the processes that are accountable for liver failure. Our model based approach shows that cell death is one of the important processes but not the sole controlling process responsible for liver failure. Additionally, our simulations showed wide variation in the timescale of liver failure that is consistent with the clinically observed timescales of post hepatectomy liver failure scenarios. Liver failure can take place either instantaneously or after a certain delay. We analyzed a virtual patient cohort and concluded that remnant liver fraction is a key regulator of the timescale of liver failure, with higher remnant liver fraction leading to longer time delay prior to failure. Our results suggest that, for a given remnant liver fraction, modulating a combination of cell death controlling parameters and metabolic load may help shift the clinical outcome away from post hepatectomy liver failure towards normal recovery.

Long-term Nucleos(t)ides Analogues for Chronic Hepatitis B Improve Liver and Spleen Size: A Noninvasive Sonographic Study

Background:

Histological improvement and regression of liver fibrosis after long-term use of nucleos(t)ides analogues (NUCs) have been documented. The aim of the present investigation was to evaluate the usefulness of traditional sonography to detect hepatic and splenic changes during NUC therapy in chronic hepatitis B (CHB) patients.

Methods:

A total of 181 CHB patients receiving NUC treatment were enrolled in this study. The study population was divided into three groups 72 cirrhotic, 58 noncirrhotic CHB, and 51 nonreplicative hepatitis B virus carriers. All patients had blood chemistries taken and sonography at baseline and during the NUC treatment period. The changes in liver size, liver edge, spleen size, platelet count, and platelet count/spleen diameter (PC/SD) ratio were compared among the three groups of patients.

Results:

CHB Patients with and without cirrhosis have improved clinical features during NUC therapy with lower aspartate aminotransferase, alanine aminotransferase, international normalized ratio, hepatitis B virus DNA, and spleen size and higher platelet, liver edge, liver size, and PC/SD ratio compared with the baseline data (p < 0.05). The differences in liver edge, liver size, spleen size, and PC/SD ratio are higher in the cirrhosis group than in the non-cirrhotic group (p < 0.001). A decrease in spleen size exhibited a linear relationship with treatment duration (R² = 0.905).

Conclusions:

Traditional sonography is helpful to monitor changes in liver fibrosis of CHB patients under NUC therapy.

Abbreviations: AFP, α-fetoprotein; ALT, alanine transaminase; AST, aspartate transaminase; CHB, chronic hepatitis B; Hb, hemoglobin; HBV, hepatitis B virus; INR, international normalized ratio; NUCs, nucleos(t)ides analogues; PC/SD, platelet count/spleen diameter; WBC, white blood cells.

Abdul Aziz G, A. Amin H, N. Mustafa H, A. Elhaggagy A. Immunohistochemical Study of the Ameliorative Effect of Vitamin E on Liver Regeneration after Different Periods of Partial Hepatectomy

The liver is almost unique in its capacity for regeneration after hepatectomy but the exact mechanisms are not yet fully clarified. Antioxidants have been shown to promote liver regeneration after major hepatectomy. The present study evaluated the ameliorative effect of vitamin E administration on the liver regeneration after different periods of partial hepatectomy (PH) in rats. Fifty-six adult male albino rats were divided into three groups: Control sham operated group; partially hepatectomized group which were divided into three subgroups sacrificed at 1day, 3 days and 7days after the operation respectively; Partially Hepatectomized group with vitamin E pretreatment before PH where the rats were given a daily oral dose of vitamin E until the time of sacrifice of the rats. Immunohistochemical detection of proliferating cell nuclear antigen (PCNA) and labeling index were demonstrated. After PH, the PCNA positive hepatocytes and the PCNA labeling indices were significantly high after the 1st day and then much decreased after the 3rd day, to be followed by a slight increase at the 7th day. Vitamin E pretreatment in PH rats resulted in a decrease in PCNA positive cells and its labeling indices in the 1st day with a gradual increase in the 3rd and 7th days. Vitamin E has an inhibitory effect in the first 24 hours on liver regeneration followed by stimulatory effect at the third and seventh days after PH. These data indicated that vitamin E pretreatment has an important role in regulation and enhancement of liver regeneration after PH.

Three Dimensional Culture Upregulates Extracellular Matrix Protein Expression in Human Liver Cell Lines - a Step towards Mimicking the Liver in Vivo?

Extracellular matrix (ECM) in the liver affects the phenotype of both hepatocytes and non-parenchymal cells. To be able to mimic in vivo liver function for extracorporeal hepatic support using human cell lines, a necessary step is to upregulate the function normally seen in monolayer culture. 3-D spheroid colonies were formed by culturing single HepG2 cells encapsulated in alginate beads. ECM expression in these cultures was compared to monolayer Hep G2 cultures. The following ECM proteins were detected immunohistochemically:- collagens I, III, V and VI, the glycoproteins fibronectin, tenascin and vitronectin, and the basement membrane protein laminin. In 3-D cultures, all proteins except tenascin were strongly expressed, as compared with weak or undetectable expression in monolayer cultures, even with 10-fold increases in the antibody concentration used. In conclusion, we have demonstrated that the 3-D environment created by alginate encapsulation of cell lines leads to cell behaviour mimicking that in vivo.

Growth of liver allografts over time in pediatric transplant recipients

The liver's capacity to grow in response to metabolic need is well known. However, long-term growth of liver allografts in pediatric recipients has not been characterized. A retrospective review of pediatric recipients at a single institution identified patients who had cross-sectional imaging at 1, 5, and 10 years post-transplant. Using volumetric calculations, liver allograft size was calculated and percent SLV were compared across the different time points; 18 patients ranging from 0.3 to 17.7 years old were identified that had imaging at 2 or more time points. Measured liver volumes increased by 59% after 5 years and 170% after 10 years. The measured liver volumes compared to calculated %SLV for these patients were 123 ± 37%, 97 ± 19%, and 118 ± 27% at 1, 5, and 10 years after transplant, respectively. Our data suggest that liver allografts in pediatric recipients increase along with overall growth, and reach SLVs for height and weight by 5 years post-transplantation. Additionally, as pediatric recipients grow, the livers appear to maintain appropriate SLV.

Major liver resection reduces nonprotein respiratory quotient and increases nonesterified fatty acid at postoperative day 14 in patients with hepatocellular carcinoma

BACKGROUND & AIMS

We reported decreased nonprotein respiratory quotient (npRQ) after liver resection in patients with hepatocellular carcinoma (HCC); however, whether liver resection volume affects energy metabolism in these patients is unclear. We aimed to examine the relationship between liver resection and energy metabolism indices.

METHODS

NpRQ was measured in 53 patients with HCC and seven with at the pre- and postoperative days. Patients were classified into four groups: Minor-lowICG group (n = 17): minor (subsegment or less) resection and low indocyanine green retention rate at 15 min (ICGR15) (<15%); Minor-highICG group (n = 18): minor resection and high ICGR15 (≥15%) and Major-lowICG group (n = 18): major (lobe) resection and low ICGR15 (<15%). We investigated dietary intake and blood biochemistry at energy measurement. The difference in npRQ and nonesterified fatty acid (NEFA) pre- and post-hepatectomy was shown as ΔnpRQ and ΔNEFA, respectively.

RESULTS

Compared with the preoperative values, npRQ significantly decreased in the Minor-highICG and Major-lowICG groups and NEFA significantly increased in the Major-lowICG group at postoperative day 14. In single regression analysis, ΔnpRQ significantly correlated with HCV infection and ΔNEFA with resection volume, HCV infection, and ICGR15. In multiple regression analysis, ΔNEFA significantly correlated with resection volume after adjusting for age, etiology, and ICGR15.

CONCLUSIONS

These results suggest that postoperative nutritional recovery is slower in major resection than in minor resection patients. Hence, nutritional care to prevent starvation is needed in major resection patients.

A prediction model for the grade of liver fibrosis using magnetic resonance elastography

BACKGROUND

Liver stiffness measurement (LSM) has recently become available for assessment of liver fibrosis. We aimed to develop a prediction model for liver fibrosis using clinical variables, including LSM.

METHODS

We performed a prospective study to compare liver fibrosis grade with fibrosis score. LSM was measured using magnetic resonance elastography in 184 patients that underwent liver resection, and liver fibrosis grade was diagnosed histologically after surgery. Using the prediction model established in the training group, we validated the classification accuracy in the independent test group.

RESULTS

First, we determined a cut-off value for stratifying fibrosis grade using LSM in 122 patients in the training group, and correctly diagnosed fibrosis grades of 62 patients in the test group with a total accuracy of 69.3%. Next, on least absolute shrinkage and selection operator analysis in the training group, LSM (r = 0.687, P < 0.001), indocyanine green clearance rate at 15 min (ICGR15) (r = 0.527, P < 0.001), platelet count (r = -0.537, P < 0.001) were selected as variables for the liver fibrosis prediction model. This prediction model applied to the test group correctly diagnosed 32 of 36 (88.8%) Grade I (F0 and F1) patients, 13 of 18 (72.2%) Grade II (F2 and F3) patients, and 7 of 8 (87.5%) Grade III (F4) patients in the test group, with a total accuracy of 83.8%.

CONCLUSIONS

The prediction model based on LSM, ICGR15, and platelet count can accurately and reproducibly predict liver fibrosis grade.

The Role of Infected Cell Proliferation in the Clearance of Acute HBV Infection in Humans

Around 90-95% of hepatitis B virus (HBV) infected adults do not progress to the chronic phase and, instead, recover naturally. The strengths of the cytolytic and non-cytolytic immune responses are key players that decide the fate of acute HBV infection. In addition, it has been hypothesized that proliferation of infected cells resulting in uninfected progeny and/or cytokine-mediated degradation of covalently closed circular DNA (cccDNA) leading to the cure of infected cells are two major mechanisms assisting the adaptive immune response in the clearance of acute HBV infection in humans. We employed fitting of mathematical models to human acute infection data together with physiological constraints to investigate the role of these hypothesized mechanisms in the clearance of infection. Results suggest that cellular proliferation of infected cells resulting in two uninfected cells is required to minimize the destruction of the liver during the clearance of acute HBV infection. In contrast, we find that a cytokine-mediated cure of infected cells alone is insufficient to clear acute HBV infection. In conclusion, our modeling indicates that HBV clearance without lethal loss of liver mass is associated with the production of two uninfected cells upon proliferation of an infected cell.

Evaluating the regenerative potential and functionality of human liver cells in mice

Liver diseases afflict millions of patients worldwide. Currently, the only long-term treatment for liver failure is the transplantation of a new liver. However, intravenously transplanting a suspension of human hepatocytes might be a less-invasive approach to partially reconstitute lost liver functions in human patients as evinced by promising outcomes in clinical trials. The purpose of this essay is to emphasize outstanding questions that continue to surround hepatocyte transplantation. While adult primary human hepatocytes are the gold standard for transplantation, hepatocytes are heterogeneous. Whether all hepatocytes engraft equally and what specifically defines an "engraftable" hepatocyte capable of long-term liver reconstitution remains unclear. To this end, mouse models of liver injury enable the evaluation of human hepatocytes and their behavior upon transplantation into a complex injured liver environment. While mouse models may not be fully representative of the injured human liver and human hepatocytes tend to engraft mice less efficiently than mouse hepatocytes, valuable lessons have nonetheless been learned from transplanting human hepatocytes into mouse models. With an eye to the future, it will be crucial to eventually detail the optimal biological source (whether in vivo- or in vitro-derived) and presumptive heterogeneity of human hepatocytes and to understand the mechanisms through which they engraft and regenerate liver tissue in vivo.

Metabolic liver function in humans measured by 2-18F-fluoro-2-deoxy-D-galactose PET/CT-reproducibility and clinical potential

Background

PET/CT with the radioactively labelled galactose analogue 2-¹⁸F-fluoro-2-deoxy-D-galactose (¹⁸F-FDGal) can be used to quantify the hepatic metabolic function and visualise regional metabolic heterogeneity. We determined the day-to-day variation in humans with and without liver disease. Furthermore, we examined whether the standardised uptake value (SUV) of ¹⁸F-FDGal from static scans can substitute the hepatic systemic clearance of ¹⁸F-FDGal (K_met, mL blood/min/mL liver tissue/) quantified from dynamic scans as measure of metabolic function.

Four patients with cirrhosis and six healthy subjects underwent two ¹⁸F-FDGal PET/CT scans within a median interval of 15 days for determination of day-to-day variation. The correlation between K_met and SUV was examined using scan data and measured arterial blood concentrations of ¹⁸F-FDGal (blood samples) from 14 subjects from previous studies. Regional and whole-liver values of K_met and SUV along with total metabolic liver volume and total metabolic liver function (total SUV, average SUV multiplied by total metabolic liver volume) were calculated.

Results

No significant day-to-day differences were found for K_met or SUV. SUV had higher intraclass correlation coefficients than K_met (0.92–0.97 vs. 0.49–0.78). The relationship between K_met and SUV was linear. Total metabolic liver volume had non-significant day-to-day variation (median difference 50 mL liver tissue; P = 0.6). Mean total SUV in healthy subjects was 23,840 (95% CI, 21,609; 26,070), significantly higher than in the patients (P < 0.001).

Conclusions

The reproducibility of ¹⁸F-FDGal PET/CT was good and SUV can substitute K_met for quantification of hepatic metabolic function. Total SUV of ¹⁸F-FDGal is a promising tool for quantification of metabolic liver function in pre-treatment evaluation of individual patients.

Perioperative Liver Function after Hepatectomy in a Tertiary University Hospital in Damascus

Background:

Liver resection is the only viable therapeutic treatment option for several neoplastic entities of the liver. Although, the number of resectable patients is increasing in Syria, liver failure is still a major complication affecting mortality and morbidity rates.

Methods:

Between 2009 and 2016, 104 patients undergoing liver resection in Damascus University Faculty of Medicine were retrospectively analyzed. Liver function tests were conducted before surgery (ps) and in the perioperative period (po) and comparisons were performed with division into anatomic VS non-anatomic or malignant VS non-malignant groups.

Results:

Liver synthetic, excretory and detoxifying functions deteriorated after liver resection (INR ps ‘presurgery’=1.129 po ‘perioperative’=1.426 P<0.001, TP ps=7.426 po=5.581 P<0.001, ALB ps=4.204 po=3.242 P<0.001, T-Bill ps=0.061 po=0.136 P<0.001) and liver cell necrosis increased after resection (ALT ps=27.597 po=200.221 P<0.001, AST ps=33.395 po=190.553 P<0.001). There was no significant difference in liver functions when we compared anatomic VS non-anatomic groups or malignant VS non-malignant groups, but liver cell necrosis was higher with malignancies (ALT malignant group=236.475 non-malignant group=89.5 P=0.002, AST malignant group=222.644 non-malignant group=101.125 P=0.001).

Conclusion:

Although liver resection affects liver function significantly, no differences in outcomes were found between anatomic VS non anatomic or malignant VS non-malignant groups.

A proton therapy model using discrete difference equations with an example of treating hepatocellular carcinoma

Proton therapy is a type of radiation therapy used to treat cancer. It provides more localized particle exposure than other types of radiotherapy (e.g., x-ray and electron) thus reducing damage to tissue surrounding a tumor and reducing unwanted side effects. We have developed a novel discrete difference equation model of the spatial and temporal dynamics of cancer and healthy cells before, during, and after the application of a proton therapy treatment course. Specifically, the model simulates the growth and diffusion of the cancer and healthy cells in and surrounding a tumor over one spatial dimension (tissue depth) and the treatment of the tumor with discrete bursts of proton radiation. We demonstrate how to use data from in vitro and clinical studies to parameterize the model. Specifically, we use data from studies of Hepatocellular carcinoma, a common form of liver cancer. Using the parameterized model we compare the ability of different clinically used treatment courses to control the tumor. Our results show that treatment courses which use conformal proton therapy (targeting the tumor from multiple angles) provides better control of the tumor while using lower treatment doses than a non-conformal treatment course, and thus should be recommend for use when feasible.