Hepatic stellate cells are involved in the pathogenesis of acute-on-chronic liver failure (ACLF)

Non-alcoholic fatty liver disease (NAFLD) in lean individuals - Single centre large cohort clinicopathologic and immunophenotypic study

BACKGROUND

Non-alcoholic fatty liver disease is one of the most common causes of chronic liver diseases and occurs even in lean individuals having normal or low body mass index (BMI). Crucial issue is understanding the clinical, pathobiologic and metabolic characteristics in comparison to obese patients. Very few studies have compared clinicopathological characteristics between lean and obese. Published literature is generally in a small cohort of patients, rarely included over-weight as separate category, and most often had non-standardized use of BMI criteria with discordant conclusions. There is very sparse published literature on liver biopsy-confirmed cohort and that to from Asia; also, none had explored the role of mediators such as stellate cells, progenitor cells and macrophages.

AIMS

To evaluate the prevalence of NAFLD in lean patients in a large cohort of histology-confirmed NAFLD, and explore clinico-pathological spectrum of lean NAFLD in comparison to over-weight and obese. Also, to investigate role of hepatic stellate cells, macrophage polarization and their relation to hepatic progenitor cells, in particular the relation to fibrosis and to different BMI categories.

METHODS

Prospective analysis of eleven-year retrospective cross-sectional data of all consecutive patients of NAFLD diagnosed in the period between the year 2011 and 2021. All histologically confirmed cases of NAFLD fulfilling inclusion and exclusion criteria were stratified to three groups according to BMI based on Asian criteria. Demographic, lab, metabolic, and histological comparisons between lean and overweight-obese patients were performed. Histological grading and staging of NAFLD components were performed by NAS-CRN score. Immunohistochemical and image analysis-based assessment and quantification of stellate cells, progenitor cells, and macrophage polarization was performed. Appropriate statistical methods were applied, and study was approved by the Institutional ethics committee.

RESULTS

Lean patients with biopsy-proven diagnosis constituted 21 % (n = 267) of total NAFLD (n = 1273). Other groups were-over-weight patients (232;18.2 %), and the highest were obese patients (774; 60.8 %). 13.9 % of the lean patients with NAFLD were under-weight with BMI<18.5 kg/m2. Lean patients had significantly lower BMI and waist circumference along with lesser fasting glucose levels in comparison to the other groups. Rest of the metabolic parameters were nearly similar. Lean patients showed higher serum ALT levels, and histological characteristics such as ballooning of hepatocytes and steatosis were also more marked in comparison to other groups. Lobular inflammation and advanced fibrosis were significantly less common in lean patients with NASH related cirrhosis found in only 20.9 % of them. Immunophenotypic studies revealed the inter-relationship of HPCs, HSCs, and macrophages was influenced by the stage of fibrosis and not by the BMI.

CONCLUSIONS

Prevalence of NAFLD in lean individuals in a histological-confirmed patient cohort was 21 %. (n = 267/1273). Major strengths of this study are large cohort of lean individuals from a single center, inclusion of only histology-confirmed cases, Asia specific BMI criteria usage, comparative clinical, metabolic, immune-morphologic and image analysis-based characterization, inclusion of over-weight in addition to obese patients, and investigating cross-talk of principal patho-physiologic markers.

Second-harmonic generation (SHG) microscopy and hepatic venous pressure gradient-based validation of a novel histological staging system for alcoholic hepatitis

Alcoholic hepatitis (AH) lacks specific histological staging. A novel fibrosis staging that encompasses perisinusoidal fibrosis and cirrhosis sub-stages, substantiated by Hepatic venous pressure gradient (HVPG) and automated fibrosis quantification, is imperative. To correlate novel histological staging system of AH with second-harmonic generation microscopy (SHG)-based q-fibrosis, HVPG, and activated hepatic stellate cells (HSCs). Liver biopsies of AH (n = 175) were staged semi-quantitatively as F0, F1, F2, F3A and F3B and Laennec substages of cirrhosis 4A, 4B and 4C. Stages were correlated with SHG q-fibrosis parameters, HVPG and HSCs. Mean age 41.2 ± 9.4 years, 96.6% males, bilirubin 20.58 ± 8.0 mg/dl and Maddrey's discriminant function 78.9 ± 36.7 displayed advanced fibrosis in 98.6%. With increasing histological stages, an increase in q-fibrosis indices and mean HVPG (p < 0.0001) were recorded; stage 4C showed the most significant difference from other stages (p < 0.000). Stages 3A and 3B were comparable with the stages 4A and 4B, respectively, for q-fibrosis (p = 1) and HVPG (p = 1). HSCs (> 30%) were significantly higher in stage 3 (75%) compared with 4 (49%) and 2 (59%), p = 0.018. Overall agreement for histological staging was excellent for all stages (0.82). SHG quantified fibrosis and HVPG corroborates the novel histological staging of AH. Expansive PCF matches with collagen content and clinical severity to early sub-stages of cirrhosis. This highlights the need for an accurate quantification and inclusion of PCF as a separate stage. SHG-based quantification can be a useful adjunct to histological fibrosis staging systems.

Acute-on-chronic liver failure: consensus recommendations of the Asian Pacific association for the study of the liver (APASL): an update

The first consensus report of the working party of the Asian Pacific Association for the Study of the Liver (APASL) set up in 2004 on acute-on-chronic liver failure (ACLF) was published in 2009. With international groups volunteering to join, the "APASL ACLF Research Consortium (AARC)" was formed in 2012, which continued to collect prospective ACLF patient data. Based on the prospective data analysis of nearly 1400 patients, the AARC consensus was published in 2014. In the past nearly four-and-a-half years, the AARC database has been enriched to about 5200 cases by major hepatology centers across Asia. The data published during the interim period were carefully analyzed and areas of contention and new developments in the field of ACLF were prioritized in a systematic manner. The AARC database was also approached for answering some of the issues where published data were limited, such as liver failure grading, its impact on the 'Golden Therapeutic Window', extrahepatic organ dysfunction and failure, development of sepsis, distinctive features of acute decompensation from ACLF and pediatric ACLF and the issues were analyzed. These initiatives concluded in a two-day meeting in October 2018 at New Delhi with finalization of the new AARC consensus. Only those statements, which were based on evidence using the Grade System and were unanimously recommended, were accepted. Finalized statements were again circulated to all the experts and subsequently presented at the AARC investigators meeting at the AASLD in November 2018. The suggestions from the experts were used to revise and finalize the consensus. After detailed deliberations and data analysis, the original definition of ACLF was found to withstand the test of time and be able to identify a homogenous group of patients presenting with liver failure. New management options including the algorithms for the management of coagulation disorders, renal replacement therapy, sepsis, variceal bleed, antivirals and criteria for liver transplantation for ACLF patients were proposed. The final consensus statements along with the relevant background information and areas requiring future studies are presented here.

Role of stellate cells in hepatic echinococcosis in cattle

Hydatid cysts formed by the metacestodes of Echinococcus granulosus. Cattle suffering from hydatid cyst shows fluid-filled structures, especially in liver. These parasite-induced cysts localized by forming fibrous capsules in the liver. Fibrogenesis is the host immune response in the liver against these parasites. Hepatic stellate cells (HSCs) are localized perisinusoidal space also known as vitamin A-storing cells, characterize the important fibrogenic cell type. In this study, livers from 15 animals with hydatid cyst and 8 healthy animals were used. Hematoxylin and Eosin, masson trichrome staining were performed on the prepared liver sections. Microscopically, cysts were bordered eosinophilic necrotic debris blended with degenerate neutrophils, macrophages, eosinophils, lymphocytes, plasma cells and multinucleated giant cells, which extend into the adjacent fibrous connective tissue. In Masson trichrome staining, the fibrous connective tissue was observed surrounding of hydatid cyst. Glial fibrillary acidic protein (GFAP), collagen I, GFAP/collagen I, positive cells were investigated using either indirect single- or double-labeling immunohistochemical staining. The results indicated that anti-GFAP-positive staining was seen in areas including fibrous tissue just under the foreign body giant cells surrounding the cyst wall. In double immunohistochemical staining, it was observed that HSCs labeled with anti-GFAP antibody in the fibrous connective tissue also labeled anti-collagen I antibody. This study shows that HSCs may responsible for synthesis the collagen I in the development of parasitic fibrosis in cystic echinococcosis in the liver of cattle.

Early cirrhosis and a preserved bone marrow niche favour regenerative response to growth factors in decompensated cirrhosis

BACKGROUND

Exogenous growth factor-mobilized bone marrow (BM) stem cells have shown a differential response in the management of decompensated cirrhosis (DC). This study was designed to evaluate potential clinical benefit of adding Erythropoietin (EPO) in granulocyte-colony stimulating factor (G-CSF)-mobilized stem cell therapy, possible mechanisms of regeneration and predictive factors of regenerative response.

METHODS

Sixty consecutive DC patients received either G-CSF with EPO (Group A; n = 30) or G-CSF and placebo (Group B; n = 30) for 2 months and were carefully followed up for 1 year. Baseline and post-treatment liver biopsy, BM biopsy and BM aspirate were analysed for fibro-inflammatory and regenerative response and BM hematopoietic reservoir.

RESULTS

Addition of EPO to G-CSF showed a significant improvement in Child-Pugh score (P = 0.03) and MELD score (P = 0.003) as compared to G-CSF alone, with reduction in mortality (16.6% vs 36.7%, P = 0.09). The combination arm also demonstrated a decreased incidence of acute kidney injury (P < 0.001), encephalopathy (P = 0.005) and refilling of ascites (P = 0.03). Compared to monotherapy, it increased CD163+ macrophages (P = 0.013), Ki67+ index (P < 0.001) with decrease in α-SMA levels (P < 0.001) in liver tissue. The response was better with grade 1 and 2 than with grade 3 ascites; Child B cirrhosis and MELD < 16. Non-responders had lower hematopoietic stem cells (HSCs) at baseline. On multivariate analysis, the liver disease severity (MELD < 16) and a relatively preserved BM (BM-HSCs > 0.4) predicted therapeutic response (AUROC = 0.82).

CONCLUSIONS

Early DC (MELD < 16) patients with mild-moderate ascites and those with a healthy cellular baseline BM respond better to growth factor therapy. Addition of EPO to G-CSF provides better regenerative response than G-CSF monotherapy.

Role of mitophagy regulation by ROS in hepatic stellate cells during acute liver failure

Liver sinusoids serve as the first line of defense against extrahepatic stimuli from the intestinal tract. Hepatic stellate cells (HSCs) are pericytes residing in the perisinusoidal space that integrate cytokine-mediated inflammatory responses in the sinusoids and relay these signals to the liver parenchyma. Oxidative stress has been shown to promote inflammation during acute liver failure (ALF). Whether and how oxidative stress is involved in HSC inflammation during ALF remains unclear. Level of systemic oxidative stress is reflected by superoxide dismutase (SOD). Thus, ALF patients were recruited to investigate the correlation between plasma SOD levels and clinical features. Liver tissues were collected from chronic hepatitis patients by biopsy and from ALF patients who had undergone liver transplantation. SOD2 expression and HSCs activation were investigated by immunohistochemistry. Inflammation, mitophagy, and apoptosis were investigated by immunoblot analysis and flow cytometry in HSCs treated with lipopolysaccharide (LPS) and reactive oxygen species (ROS) donors. The plasma SOD level was significantly increased in patients with ALF compared with those with cirrhosis (444.4 ± 23.58 vs. 170.07 ± 3.52 U/ml, P < 0.01) and was positively correlated with the Model for End-Stage Liver Disease-Na score ( R² = 0.4720, P < 0.01). In vivo observations revealed that SOD2 immunostaining was increased in ALF patients and mice models, and in vitro experiments demonstrated that LPS/ROS promoted inflammation via inhibiting mitophagy. Moreover, the regulation of inflammation was apoptosis independent in HSCs. LPS-induced increases in oxidative stress promote inflammation through inhibiting mitophagy in HSCs during the process of ALF, providing a novel strategy for the treatment of patients with ALF. NEW & NOTEWORTHY Here we demonstrate that the serum superoxide dismutase (SOD) level is significantly increased in patients with acute liver failure (ALF), and, correlated with the Model for End-Stage Liver Disease-Na score, SOD level dropped in the remission stage of ALF. We identify that, in liver tissue from ALF patients and mice models, manganese-dependent SOD was overexpressed, and show lipopolysaccharide/H₂O₂ inhibits mitophagy via reactive oxygen species in hepatic stellate cells (HSCs). We show that inhibited mitophagy promotes inflammation in HSCs, whereas mitophagy inducer rescues HSCs from lipopolysaccharide-induced inflammation.

The Effects of Betaine on the Nuclear Fractal Dimension, Chromatin Texture, and Proliferative Activity in Hepatocytes in Mouse Model of Nonalcoholic Fatty Liver Disease

The effects of betaine on hepatocytes chromatin architecture changes were examined by using fractal and gray-level co-occurrence matrix (GLCM) analysis in methionine/choline-deficient (MCD) diet-induced, nonalcoholic fatty liver disease (NAFLD). Male C57BL/6 mice were divided into groups: (1) Control: standard diet; (2) BET: standard diet and betaine supplementation through drinking water (solution 1.5%); (3) MCD group: MCD diet for 6 weeks; (4) MCD+BET: fed with MCD diet + betaine for 6 weeks. Liver tissue was collected for histopathology, immunohistochemistry, and determination of fractal dimension and GLCM parameters. MCD diet induced diffuse micro- and macrovesicular steatosis accompanied with increased Ki67-positive hepatocyte nuclei. Steatosis and Ki67 immunopositivity were less prominent in the MCD+BET group compared with the MCD group. Angular second moment (ASM) and inverse difference moment (IDM) (textural homogeneity markers) were significantly increased in the MCD+BET group versus the MCD group (p<0.001), even though no difference between the MCD and the control group was evident. Heterogeneity parameters, contrast, and correlation were significantly increased in the MCD group versus the control (p<0.001). On the other hand, betaine treatment significantly reduced correlation, contrast, and entropy compared with the MCD group (p<0.001). Betaine attenuated MCD diet-induced NAFLD by reducing fat accumulation and inhibiting hepatocyte proliferation. Betaine supplementation increased nuclear homogeneity and chromatin complexity with reduction of entropy, contrast, and correlation.

Serum osteopontin is a predictor of prognosis for HBV-associated acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) is a syndrome with a high rate of short-term mortality, and clinically it is important to identify patients at high risk of mortality. The present study evaluated the value of osteopontin (OPN) in the prediction of 90-day mortality in patients with ACLF. A total of 54 patients with HBV-associated ACLF were enrolled, and serum OPN levels were determined in a prospective, observational study design. Survival analysis was performed using Kaplan-Meier curves, and multivariate Cox proportional hazards regression was used to analyze independent risk factors of mortality. Serum OPN was significantly higher in HBV-ACLF patients compared with patients with chronic hepatitis B and healthy controls (both P<0.01), and furthermore, was higher in those patients who succumbed to HBV-ACLF compared with surviving patients (P<0.05). OPN level positively correlated with total bilirubin (r=0.554, P<0.001), Model for End-Stage Liver Disease (MELD) score (r=0.234, P=0.038), MELD-Na score (r=0.379, P=0.005) and monocyte count (r=0.282, P=0.039), and OPN was an independent risk factor for 90-day mortality in ACLF (P=0.021, odds ratio=1.104, 95% confidence interval: 1.003-1.116). Furthermore, ACLF patients were stratified into three groups according to serum OPN levels (low mortality risk: <6,135 ng/ml; intermediate risk: 6,135-9,043 ng/ml; and high risk: >9,043 ng/ml), for which the 90-day mortality rates were 27.78 (5/18), 52.94 (9/17) and 73.68% (14/19), respectively, and those in the high risk had a poorer prognosis compared with the low risk group (P=0.009). In conclusion, serum OPN may be an independent risk factor associated with HBV-ACLF prognosis.

Reviewing the diagnostic criteria for acute-on-chronic liver failure

For over 20 years, acute-on-chronic liver failure (ACLF) has taken multiple definitions and/or classifications. The definition outlines the acute and chronic insults to include a homogenous patient group with liver failure and an expected outcome in a specific time frame. Early and accurate diagnosis is essential as this inflammation of the liver may tilt the balance of liver destruction and regeneration adversely. Various factors such as superadded systemic sepsis, liver reserve, cause of primary chronic liver disease, state of immune system or the state of gut microbial flora might determine the ultimate prognosis. Areas covered: To date, there has been no universally accepted definition of ACLF. In this review, we discuss the strengths and weaknesses, controversies and basis for early identification and accurate diagnosis of ACLF. PubMed and Google scholar database searches were conducted, search terms included 'acute on chronic liver failure,' 'ACLF,' and 'diagnostic criteria.' Expert commentary: With recent advances in the management of advanced cirrhosis, research will gradually shift towards ACLF in the near future, focusing on the pathogenesis, new treatment options and improving survival. Once we improve understanding of this syndrome, newer definitions will evolve, thereby enabling earlier diagnosis and novel therapeutic avenues.

Acute-on-chronic liver failure: terminology, mechanisms and management

Acute-on-chronic liver failure (ACLF) is a distinct clinical entity and differs from acute liver failure and decompensated cirrhosis in timing, presence of acute precipitant, course of disease and potential for unaided recovery. The definition involves outlining the acute and chronic insults to include a homogenous patient group with liver failure and an expected outcome in a specific timeframe. The pathophysiology of ACLF relates to persistent inflammation, immune dysregulation with initial wide-spread immune activation, a state of systematic inflammatory response syndrome and subsequent sepsis due to immune paresis. The disease severity and outcome can be predicted by both hepatic and extrahepatic organ failure(s). Clinical recovery is expected with the use of nucleoside analogues for hepatitis B, and steroids for severe alcoholic hepatitis and, possibly, severe autoimmune hepatitis. Artificial liver support systems help remove toxins and metabolites and serve as a bridge therapy before liver transplantation. Hepatic regeneration during ongoing liver failure, although challenging, is possible through the use of growth factors. Liver transplantation remains the definitive treatment with a good outcome. Pre-emptive antiviral agents for hepatitis B before chemotherapy to prevent viral reactivation and caution in using potentially hepatotoxic drugs can prevent the development of ACLF.

Is toxoplasmosis a potential risk factor for liver cirrhosis?

OBJECTIVE

To document Toxoplasma gondii (T. gondii) antibody status in patients with liver disease, blood samples were taken from 180 hepatic patients and 180 healthy controls.

METHODS

Toxoplasma IgG antibody was detected using enzyme-linked immunosorbent assay and histopathological assessment of liver biopsy METAVIR score was applied.

RESULTS

Anti-T. gondii IgG antibodies were found in 32.8% of patients and in 22.2% of controls (P = 0.02). Toxoplasma seropositivity was significantly associated with lymphadenopathy, history of blood transfusion and reflex impairment in patients. Chronic hepatitis C virus (HCV) and chronic HCV-related cirrhosis groups compared to chronic HBV and chronic HBV-related cirrhosis groups expressed significantly higher prevalence of T. gondii seropositivity (odds ratio (OR) = 4; 95% confidence interval (CI): 1.3-12.6; P = 0.013, OR = 4.8; 95% CI: 1.5-14.9; P = 0.006, respectively). Within the chronic HCV group, T. gondii seropositivity significantly associated disease evolution as regards to METAVIR histopathological system for fibrosis and inflammation (OR = 19.4; 95% CI: 2.3-165.2; P = 0.0008, OR = 0.29; 95% CI: 0.1-0.8; P = 0.01, respectively). Albumin, international normalized ratio (INR) and platelets count were the laboratory parameters significantly altered in Toxoplasma-positive chronic HCV patients (P = 0.001, 0.03, 0.04, respectively). Child-Pugh scoring for cirrhosis in chronic HCV group placed the majority of seropositive patient in class C with significant statistical difference compared to Child A reference group (OR = 0.08; 95% CI: 0.01-0.5; P = 0.003).

CONCLUSIONS

Toxoplasma seropositivity was high in patients with cirrhosis and associated higher grades of inflammation and necrosis signifying disease evolution, suggesting that cirrhotic patients may thus form a risk group for toxoplasmosis.

Hepatic cell proliferation plays a pivotal role in the prognosis of alcoholic hepatitis

BACKGROUND & AIMS

The role of liver progenitor cell (LPC) expansion, known as a marker of disease severity, as well as the impact of macrophage activation on liver regeneration remains unclear in humans. We aimed to characterize the LPC and macrophage compartments in alcoholic hepatitis (AH), as well as gene expression patterns to identify predictors of a good prognosis in this setting.

METHODS

Immunohistochemical studies for macrophages, proliferative hepatocytes, total and proliferative LPC, as well as whole liver microarray gene expression were performed on baseline liver biopsies of 58 AH patients early after admission. Abstinent cirrhotic patients were used as controls. Patients were qualified as "improvers" or "non-improvers" based on the change in MELD score three months after baseline.

RESULTS

Compared to controls, AH patients demonstrated a significant expansion of macrophages, invasion of LPC and a higher number of proliferating hepatocytes and LPC. In AH patients, total LPC expansion (total Keratin7(+) cells) was associated with liver disease severity. The group of improvers (n=34) was characterized at baseline by a higher number of proliferating hepatocytes, proliferative LPC (double Keratin7(+)Ki67(+) cells) and liver macrophages as compared to non-improvers (n=24), despite similar clinical and biological variables. Upregulated genes in improvers were associated with cell cycle mitosis together with a major expression of SPINK1.

CONCLUSIONS

Higher liver macrophage expansion, increased proliferative hepatocyte but also LPC number, as well as an upregulation of cell proliferation-related genes are associated with a favourable outcome. These new findings open novel therapeutic targets in AH.

Advanced therapeutic strategies for HBV-related acute-on-chronic liver failure

BACKGROUND

Acute-on-chronic liver failure (ACLF) is increasingly recognized as a distinct clinical entity and is associated with a high short-term mortality. The most common cause of ACLF is chronic hepatitis B worldwide. Currently, there is no standardized approach for the management of ACLF and the efficacy and safety of therapeutic modalities are uncertain.

DATA SOURCES

PubMed and Web of Science were searched for English-language articles. The search criteria focused on clinical trials and observational studies on the treatment of patients with HBV-related ACLF.

RESULTS

Therapeutic approaches for ACLF in patients with chronic hepatitis B included nucleos(t)ide analogues, artificial liver support systems, immune regulatory therapy, stem cell therapy and liver transplantation. All of these therapeutic approaches have shown the potential to improve liver function and increase patients' survival rate, but most of the studies were not randomized or controlled.

CONCLUSION

Substantial challenges for the treatment of HBV-related ACLF remain and further basic research and randomized controlled clinical trials are needed.

Acute-on-chronic liver failure: consensus recommendations of the Asian Pacific Association for the Study of the Liver (APASL) 2014

The first consensus report of the working party of the Asian Pacific Association for the Study of the Liver (APASL) set up in 2004 on acute-on-chronic liver failure (ACLF) was published in 2009. Due to the rapid advancements in the knowledge and available information, a consortium of members from countries across Asia Pacific, "APASL ACLF Research Consortium (AARC)," was formed in 2012. A large cohort of retrospective and prospective data of ACLF patients was collated and followed up in this data base. The current ACLF definition was reassessed based on the new AARC data base. These initiatives were concluded on a 2-day meeting in February 2014 at New Delhi and led to the development of the final AARC consensus. Only those statements which were based on the evidence and were unanimously recommended were accepted. These statements were circulated again to all the experts and subsequently presented at the annual conference of the APASL at Brisbane, on March 14, 2014. The suggestions from the delegates were analyzed by the expert panel, and the modifications in the consensus were made. The final consensus and guidelines document was prepared. After detailed deliberations and data analysis, the original proposed definition was found to withstand the test of time and identify a homogenous group of patients presenting with liver failure. Based on the AARC data, liver failure grading, and its impact on the "Golden therapeutic Window," extra-hepatic organ failure and development of sepsis were analyzed. New management options including the algorithms for the management of coagulation disorders, renal replacement therapy, sepsis, variceal bleed, antivirals, and criteria for liver transplantation for ACLF patients were proposed. The final consensus statements along with the relevant background information are presented here.

Growth factors enhance liver regeneration in acute-on-chronic liver failure

Acute-on-chronic liver failure is a distinct syndrome characterized by a rapid progression of liver disease culminating in organ failure and death. The only definitive treatment is liver transplantation. However, there is a possible element of reversibility and hepatic regeneration if the acute insult can be tided over. Exogenously administered growth factors may stimulate hepatocytes, hepatic progenitor cells and bone marrow-derived cells to supplement hepatic regeneration. The proposed review is intended to provide an in-depth analysis of the individual components of hepatic and bone marrow niches and highlight the growing role of various growth factors in liver regeneration in health and in liver failure.

Acute-on-chronic liver failure: a review

There is no universally accepted definition of acute-on-chronic liver failure; however, it is recognized as an entity characterized by decompensation from an underlying chronic liver disease associated with organ failure that conveys high short-term mortality, with alcoholism and infection being the most frequent precipitating events. The pathophysiology involves inflammatory processes associated with a trigger factor in susceptible individuals (related to altered immunity in the cirrhotic population). This review addresses the different definitions developed by leading research groups, epidemiological and pathophysiological aspects, and the latest treatments for this entity.

Two-tier regenerative response in liver failure in humans

Acute and chronic liver failure is associated with high mortality. The enormous regenerative potential of the liver has generated a lot of attention. We undertook this work to assess the two-tier regenerative response in liver failure by immunohistochemistry and to correlate such response with liver histology in acute liver failure (ALF), acute-on-chronic liver failure (ACLF), and decompensated cirrhosis (CHD). Histological examination and immunohistochemical analysis of proliferating hepatocytes and activated hepatic progenitor cells (HPCs) were performed on the liver tissue of patients with ALF (25), ACLF (70), and CHD (70). Comparative analysis of regenerative markers and correlation with histological parameters were done in ALF, ACLF, and CHD. Hepatocytes proliferated significantly more in ALF in comparison to ACLF (p < 0.001) and CHD (p < 0.001). HPC proliferation was significantly higher in ACLF (p < 0.001) and CHD (p < 0.001) than in ALF. ACLF patients showed the highest HPC proliferation and differentiation. Significantly more intermediate hepatocytes were found in ACLF than in ALF and CHD (p < 0.001). Marked parenchymal replacement by fibrosis and/or necrosis correlated significantly with activation of HPC in ACLF (p = 0.01, odds ratio (OR) 4.95) and in CHD (p = 0.05, OR 4.19). The study of liver regeneration in human acute and chronic liver failure suggests that hepatocyte proliferation, providing the first line of regeneration response, is most active in ALF whereas HPC activation, the second line of defense, is more prominent in ACLF. More HPC differentiate to hepatocytes in ACLF than in CHD, reflecting better regenerative potential in ACLF.

Hepatic stellate cells increase in Toxoplasma gondii infection in mice

BACKGROUND

Toxoplasma gondii is a ubiquitous protozoan parasite that can infect humans and animals. The severity of toxoplasmosis varies according to the immune status of the individual, parasite strain, and host species. In mammalian species, it has been observed that severe lesions of acute toxoplasmosis form in visceral organs such as the liver, lung, and spleen. Some epidemiological studies have reported an association of T. gondii infection with liver cirrhosis.

METHODS

Acute infection was induced in fifteen 30-day-old normal Swiss albino mice. The mice were infected by intraperitoneal inoculation of 5000 T. gondii RH strain tachyzoites. The mice were sacrificed in groups of 5 at 2, 4, and 6 days after inoculation. Another group of 5 mice were used as the controls. Anti-glial fibrillary acidic protein (GFAP) and anti-T. gondii antibodies were used to compare GFAP-immunoreactive cells and anti-T. gondii-immunopositive areas in the liver between the T. gondii-infected groups and the healthy controls, respectively.

RESULTS

There was a significant correlation between the numbers of GFAP-positive hepatic stellate cells (HSCs) when they were compared with T. gondii antigen immunostaining (p < 0.05). The amount of T. gondii immunostaining increased significantly with the increase in the number of HSCs.

CONCLUSIONS

There is a significant relationship between the number of HSCs and T. gondii antigens, which may represent an active role of HSCs in liver pathology and the pathobiology of T. gondii-related hepatitis.

HDAC inhibitors in experimental liver and kidney fibrosis

Histone deacetylase (HDAC) inhibitors have been extensively studied in experimental models of cancer, where their inhibition of deacetylation has been proven to regulate cell survival, proliferation, differentiation and apoptosis. This in turn has led to the use of a variety of HDAC inhibitors in clinical trials. In recent years the applicability of HDAC inhibitors in other areas of disease has been explored, including the treatment of fibrotic disorders. Impaired wound healing involves the continuous deposition and cross-linking of extracellular matrix governed by myofibroblasts leading to diseases such as liver and kidney fibrosis; both diseases have high unmet medical needs which are a burden on health budgets worldwide. We provide an overview of the potential use of HDAC inhibitors against liver and kidney fibrosis using the current understanding of these inhibitors in experimental animal models and in vitro models of fibrosis.