Inhibition of cyclooxygenase-2 alleviates liver cirrhosis via improvement of the dysfunctional gut-liver axis in rats

FXR deletion attenuates intestinal barrier dysfunction in murine acute intestinal inflammation

Accumulating literature suggests that the farnesoid-X receptor (FXR), a nuclear bile acid receptor best known for its role in bile acid homeostasis, is also a potent context-dependent regulator of inflammation. FXR may thus be relevant to several intestinal disease states including inflammatory bowel disease, necrotizing enterocolitis, and sepsis. In this study, we tested the effects of FXR deletion on acute murine intestinal inflammation. We found that FXR knockout (KO) mice were protected from intestinal injury and barrier dysfunction induced by lipopolysaccharide (LPS) injection, dithizone (DI)/Klebsiella, and cecal ligation/puncture models. In the LPS model, RNA sequencing and qPCR analysis showed that this protection correlated with substantial reduction in LPS-induced proinflammatory gene expression, including lower tissue levels of Il1a, Il1b, and Tnf. Examining functional effects on the epithelium, we found that LPS-induced tight junctional disruption as assessed by internalization of ZO-1 and occludin was ameliorated in FXR KO animals. Taken together, these data suggest a role for FXR in the intestinal barrier during inflammatory injury.NEW & NOTEWORTHY Intestinal barrier failure is a hallmark in gut-origin sepsis. We demonstrate that the intestinal barriers of farnesoid-X receptor (FXR) knockout (KO) animals are protected from inflammatory insult using multiple models of acute intestinal inflammation. This protection is due to decreased inflammatory cytokine production and maintenance of tight junctional architecture seen within the KO animals. This is the first report of FXR deletion being protective to the intestinal barrier.

Long-term intermittent oral administration of selective COX-2 inhibitor improved the clinical outcomes of COVID-19 in patients with cirrhosis

OBJECTIVES

Patients with cirrhosis are more susceptible to coronavirus disease 2019 (COVID-19) due to immune dysfunction. In this retrospective study we aimed to investigate whether suppression of mild systemic inflammation with selective cyclooxygenase-2 inhibitor (COX-2-I) during chronic care of cirrhotic patients would reduce the occurrence of acute decompensated events and improve patient prognosis of COVID-19.

METHODS

Medical records of cirrhotic patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were sequentially reviewed. The patients were divided into the COX-2-I and control groups depending on whether they took oral selective COX-2-I for over 3 months or not. The primary outcomes included the occurrence of severe/critical COVID-19, acute decompensated events, and acute-on-chronic liver failure (ACLF).

RESULTS

After propensity score matching analysis, there were 314 cases in the control group and 118 cases in the COX-2-I group. Compared with the control group, the risk of severe/critical COVID-19 in the COX-2-I group was significantly decreased by 83.1% (p = 0.004). Acute decompensated events and ACLF occurred in 23 (7.32%) and nine (2.87%) cases in the control group, but none in the COX-2-I group (p = 0.003 and 0.122). The rate of hospitalization in the COX-2-I group was significantly lower than that of the control group (3.39% vs 13.06%, p = 0.003). No patient in the COX-2-I group required intensive care unit admission.

CONCLUSIONS

Long-term intermittent oral administration of selective COX-2-I in cirrhotic patients significantly reduces the occurrence of severe/critical COVID-19, acute decompensated events, and ACLF. It may also be used for systemic inflammation caused by other pathogens.

The transcriptomic profile shows the protective effects of celecoxib on cirrhotic splenomegaly

BACKGROUND

Splenomegaly can exacerbate liver cirrhosis and portal hypertension. We have previously demonstrated that cyclooxygenase-2 (COX-2) inhibitor can attenuate cirrhotic splenomegaly. However, the mechanism of cirrhotic splenomegaly remains unclear, thus becoming the focus of the present study.

MATERIALS AND METHODS

Thioacetamide (TAA) intraperitoneal injection was used to induce cirrhotic splenomegaly. Rats were randomized into the control, TAA and TAA + celecoxib groups. Histological analysis and high-throughput RNA sequencing of the spleen were conducted. Splenic collagen III, α-SMA, Ki-67, and VEGF were quantified.

RESULTS

A total of 1461 differentially expressed genes (DEGs) were identified in the spleens of the TAA group compared to the control group. The immune response and immune cell activation might be the major signaling pathways involved in the pathogenesis of cirrhotic splenomegaly. With its immunoregulatory effect, celecoxib presents to ameliorate cirrhotic splenomegaly and liver cirrhosis. Furthermore, 304 coexisting DEGs were obtained between TAA vs. control and TAA + celecoxib vs. TAA. Gene ontology (GO) and KEGG analyses collectively indicated that celecoxib may attenuate cirrhotic splenomegaly through the suppression of splenic immune cell proliferation, inflammation, immune regulation, and fibrogenesis. The impacts on these factors were subsequently validated by the decreased splenic Ki-67-positive cells, macrophages, fibrotic areas, and mRNA levels of collagen III and α-SMA.

CONCLUSIONS

Celecoxib attenuates cirrhotic splenomegaly by inhibiting splenic immune cell proliferation, inflammation, and fibrogenesis. The current study sheds light on the therapeutic strategy of liver cirrhosis by targeting splenic abnormalities and provides COX-2 inhibitors as a novel medical treatment for cirrhotic splenomegaly.

Disruption of cholangiocyte-B cell crosstalk by blocking the CXCL12-CXCR4 axis alleviates liver fibrosis

B cells can promote liver fibrosis, but the mechanism of B cell infiltration and therapy against culprit B cells are lacking. We postulated that the disruption of cholangiocyte-B-cell crosstalk could attenuate liver fibrosis by blocking the CXCL12-CXCR4 axis via a cyclooxygenase-2-independent effect of celecoxib. In wild-type mice subjected to thioacetamide, celecoxib ameliorated lymphocytic infiltration and liver fibrosis. By single-cell RNA sequencing and flow cytometry, CXCR4 was established as a marker for profibrotic and liver-homing phenotype of B cells. Celecoxib reduced liver-homing B cells without suppressing CXCR4. Cholangiocytes expressed CXCL12, attracting B cells to fibrotic areas in human and mouse. The proliferation and CXCL12 expression of cholangiocytes were suppressed by celecoxib. In CXCL12-deficient mice, liver fibrosis was also attenuated with less B-cell infiltration. In the intrahepatic biliary epithelial cell line HIBEpiC, bulk RNA sequencing indicated that both celecoxib and 2,5-dimethyl-celecoxib (an analog of celecoxib that does not show a COX-2-dependent effect) regulated the TGF-β signaling pathway and cell cycle. Moreover, celecoxib and 2,5-dimethyl-celecoxib decreased the proliferation, and expression of collagen I and CXCL12 in HIBEpiC cells stimulated by TGF-β or EGF. Taken together, liver fibrosis can be ameliorated by disrupting cholangiocyte-B cell crosstalk by blocking the CXCL12-CXCR4 axis with a COX-2-independent effect of celecoxib.

Penthorum chinense Pursh improves type 2 diabetes mellitus via modulating gut microbiota in db/db mice

Penthorum chinense Pursh (P. chinense) has been traditionally used as hepatoprotective food and medicine for hundreds of years due to its significant antioxidant and anti-inflammatory activities. However, the efficacy and mechanisms of action of P. chinense in type 2 diabetes mellitus were not fully understood. In this study, we found that P. chinense extract (PCP) supplementation resulted in reduced body weight and hyperglycemia, improved pancreatic tissue injury and insulin sensitivity, and decreased inflammatory cytokines expression in spontaneously diabetic db/db mice. 16S rRNA gene sequencing of fecal samples showed that PCP administration decreased the abundance of Firmicutes and increased the proportion of Bacteroidetes at the phylum level. Moreover, Muribaculum, Barnesiella, Prevotella, and Mucinivorans were enriched, with Desulfovibrio and Lactobacillus lowered at the genus level in db/db mice with PCP supplementation. These results suggested that PCP may ameliorate hyperglycemia, insulin resistance, and inflammation by remodeling the gut microbiota in db/db mice.

The shaping of gut immunity in cirrhosis

Cirrhosis is the common end-stage of chronic liver diseases of different etiology. The altered bile acids metabolism in the cirrhotic liver and the increase in the blood-brain barrier permeability, along with the progressive dysbiosis of intestinal microbiota, contribute to gut immunity changes, from compromised antimicrobial host defense to pro-inflammatory adaptive responses. In turn, these changes elicit a disruption in the epithelial and gut vascular barriers, promoting the increased access of potential pathogenic microbial antigens to portal circulation, further aggravating liver disease. After summarizing the key aspects of gut immunity during homeostasis, this review is intended to update the contribution of liver and brain metabolites in shaping the intestinal immune status and, in turn, to understand how the loss of homeostasis in the gut-associated lymphoid tissue, as present in cirrhosis, cooperates in the advanced chronic liver disease progression. Finally, several therapeutic approaches targeting the intestinal homeostasis in cirrhosis are discussed.

Role of Clostridium butyricum, Bacillus subtilis, and algae-sourced β-1,3 glucan on health in grass turtle

This study investigated the effects of two probiotics namely Clostridium butyricum and Bacillus subtilis, and one prebiotic known as algae-sourced β-1,3 glucan, on the overall performances of grass turtles (Chinemys reevesii) juveniles. Growth performance, immune responses, enzymatic antioxidant activities, intestinal histomorphology, and disease resistance against the challenge with Aeromonas veronii were assessed. Two hundred and sixteen (216) juvenile turtles with an average initial weight of 106.35 ± 0.03 g were divided into four groups, each containing three replicates with 18 turtles per each replicate, which were fed a basic diet (control group, GD) and a basal diet supplemented with C. butyricum 1.0 × 10⁸ CFU per kg (GA group), or with B. subtilis 1.0 × 10⁸ CFU per kg (GB group) and with algal-sourced β-1,3-glucan 50 mg per kg (GC group), respectively. After the turtles had been fed for 60 d, 90 d, and 120 d of the experimental period, the growth performance and survival rate (SR), intestinal digestive enzyme, hepatic and intestinal antioxidant capacity, serum biochemical indexes, and immune performance were measured. The results showed that the weight gain rate and SR were significantly enhanced (P < 0.05) after fed probiotics and algae-sourced β-1,3-glucan in all test times;The pepsin, amylase, acid phosphatase, total antioxidant capacity, triglyceride, alkaline phosphatase, urea nitrogen, cholesterol, total protein, IgA, IgG, IgM at 120 d were significantly enhanced (P<0.05) after fed C. butyricum. The intestinal villi heights, widths, and the thickness of the muscle layer were significantly higher in groups GA, GB, and GC than those reared within the GD control group (P < 0.05). After injecting the challenge by A. veronii the survival rate of grass turtles in the GA group (75%) was significantly higher than the other three groups (P<0.05), while there was no significant difference between the GB and GC groups compared with the control GD group, respectively (P>0.05). Overall, these results indicated that dietary supplementation with probiotics or algae-sourced β-1,3 glucan, exhibited positive effects on C. reevesii. In particular, C. butyricum, showed the greatest improvements relating to growth, immune response, antioxidant activity, intestinal health, and disease resistance.

Rifaximin and lubiprostone mitigate liver fibrosis development by repairing gut barrier function in diet-induced rat steatohepatitis

BACKGROUND

Although gut-derived lipopolysaccharide (LPS) affects the progression of non-alcoholic steatohepatitis (NASH) pathogenesis, few studies have focused on this relationship to develop treatments for NASH.

AIMS

To explore the effects of combination with rifaximin and lubiprostone on NASH liver fibrosis through the modulation of gut barrier function.

METHODS

To induce steatohepatitis, F344 rats were fed a choline-deficient l-amino acid-defined (CDAA) diet for 12 weeks and received oral administration of rifaximin and/or lubiprostone. Histological, molecular, and fecal microbial analyses were performed. Barrier function in Caco-2 cells were assessed by in vitro assays.

RESULTS

Combination rifaximin/lubiprostone treatment significantly suppressed macrophage expansion, proinflammatory responses, and liver fibrosis in CDAA-fed rats by blocking hepatic translocation of LPS and activation of toll-like receptor 4 signaling. Rifaximin and lubiprostone improved intestinal permeability via restoring tight junction proteins (TJPs) with the intestinal activation of pregnane X receptor and chloride channel-2, respectively. Moreover, this combination increased the abundance of Bacteroides, Lactobacillus, and Faecalibacterium as well as decreased that of Veillonella resulting in an increase of fecal short-chain fatty acids and a decrease of intestinal sialidase activity. Both agents also directly suppressed the LPS-induced barrier dysfunction and depletion of TJPs in Caco-2 cells.

CONCLUSION

The combination of rifaximin and lubiprostone may provide a novel strategy for treating NASH-related fibrosis.

Rifaximin enhances the L‑carnitine‑mediated preventive effects on skeletal muscle atrophy in cirrhotic rats by modulating the gut‑liver‑muscle axis

The gut‑liver‑muscle axis is associated with the development of sarcopenia in liver cirrhosis. The present study aimed to illustrate the combined effects of rifaximin and L‑carnitine on skeletal muscle atrophy in cirrhotic rats with steatohepatitis. For this purpose, a total of 344 Fischer rats were fed a choline‑deficient L‑amino acid‑defined (CDAA) diet with the daily oral administration of rifaximin (100 mg/kg) and/or L‑carnitine (200 mg/kg), and measurements of psoas muscle mass index and forelimb grip strength were performed. After feeding for 12 weeks, blood samples, and liver, ileum and gastrocnemius muscle tissues were harvested. The effects of L‑carnitine on rat myocytes were assessed using in vitro assays. Treatment with rifaximin attenuated hyperammonemia and liver fibrosis in the CDAA‑fed rats. Moreover, it improved intestinal permeability with the restoration of tight junction proteins and suppressed the lipopolysaccharide (LPS)‑mediated hepatic macrophage activation and pro‑inflammatory response. In addition, rifaximin prevented skeletal muscle mass atrophy and weakness by decreasing intramuscular myostatin and pro‑inflammatory cytokine levels. Moreover, rifaximin synergistically enhanced the L‑carnitine‑mediated improvement of skeletal muscle wasting by promoting the production of insulin‑like growth factor‑1 and mitochondrial biogenesis, resulting in the inhibition of the ubiquitin‑proteasome system (UPS). The in vitro assays revealed that L‑carnitine directly attenuated the impairment of mitochondrial biogenesis, thereby inhibiting the UPS in rat myocytes that were stimulated with LPS or tumor necrosis factor‑α. On the whole, the present study demonstrates that the combination of rifaximin with L‑carnitine may provide a clinical benefit for liver cirrhosis‑related sarcopenia.

Chemotherapeutic Drug-Regulated Cytokines Might Influence Therapeutic Efficacy in HCC

Hepatocellular carcinoma (HCC), the most common type of liver cancer, is the second leading cause of cancer-related mortality worldwide. Processes involved in HCC progression and development, including cell transformation, proliferation, metastasis, and angiogenesis, are inflammation-associated carcinogenic processes because most cases of HCC develop from chronic liver damage and inflammation. Inflammation has been demonstrated to be a crucial factor inducing tumor development in various cancers, including HCC. Cytokines play critical roles in inflammation to accelerate tumor invasion and metastasis by mediating the migration of immune cells into damaged tissues in response to proinflammatory stimuli. Currently, surgical resection followed by chemotherapy is the most common curative therapeutic regimen for HCC. However, after chemotherapy, drug resistance is clearly observed, and cytokine secretion is dysregulated. Various chemotherapeutic agents, including cisplatin, etoposide, and 5-fluorouracil, demonstrate even lower efficacy in HCC than in other cancers. Tumor resistance to chemotherapeutic drugs is the key limitation of curative treatment and is responsible for treatment failure and recurrence, thus limiting the ability to treat patients with advanced HCC. Therefore, the capability to counteract drug resistance would be a major clinical advancement. In this review, we provide an overview of links between chemotherapeutic agents and inflammatory cytokine secretion in HCC. These links might provide insight into overcoming inflammatory reactions and cytokine secretion, ultimately counteracting chemotherapeutic resistance.

Novel Anti-inflammatory Treatments in Cirrhosis. A Literature-Based Study

Liver cirrhosis is a disease characterised by multiple complications and a poor prognosis. The prevalence is increasing worldwide. Chronic inflammation is ongoing in liver cirrhosis. No cure for the inflammation is available, and the current treatment of liver cirrhosis is only symptomatic. However, several different medical agents have been suggested as potential healing drugs. The majority are tested in rodents, but few human trials are effectuated. This review focuses on medical agents described in the literature with supposed alleviating and curing effects on liver cirrhosis. Twelve anti-inflammatory, five antioxidative, and three drugs with effects on gut microflora and the LPS pathway were found. Two drugs not categorised by the three former categories were found in addition. In total, 42 rodent studies and seven human trials were found. Promising effects of celecoxib, aspirin, curcumin, kahweol, pentoxifylline, diosmin, statins, emricasan, and silymarin were found in cirrhotic rodent models. Few indices of effects of etanercept, glycyrrhizin arginine salt, and mitoquinone were found. Faecal microbiota transplantation is in increasing searchlight with a supposed potential to alleviate cirrhosis. However, human trials are in demand to verify the findings in this review.

Anti-inflammation treatment for protection of hepatocytes and amelioration of hepatic fibrosis in rats

Chronic inflammation is considered as an important pathophysiologic mechanism of hepatic cirrhosis, which induces hepatocyte injury and activates hepatic stellate cells (HSCs), thus resulting in hepatic fibrosis. Previous studies have reported that cyclooxygenase-2 (COX-2) inhibitor can effectively treat liver fibrosis, while somatostatin (SST) analogues inhibit the activation of HSCs. The present study aimed to investigate the effects of a COX-2 inhibitor, celecoxib, combined with a SST analogue, octreotide, for protection of hepatocytes and prevention of fibrosis in a rat model of hepatic fibrosis. Therefore, a hepatic fibrosis rat model was established following peritoneal injection of thioacetamide (TAA), and the rats were then treated with a combination of celecoxib and octreotide (TAA + C). Immunohistochemistry and western blotting assays were used to assess the expression levels of proteins associated with inflammation, epithelial-mesenchymal transition (EMT), proliferation, apoptosis and autophagy. H&E staining, transmission electron microscopy and scanning electron microscopy were used to evaluate the destruction of hepatocytes. Masson's Trichrome and Sirius Red were used to measure the degree of liver fibrosis. The results demonstrated that, compared with those of the control group, the degree of liver fibrosis and the expression of the intrahepatic inflammation factors were aggravated in the TAA group. Furthermore, the apoptosis rate, EMT and autophagy of hepatocytes were also increased in the TAA group. However, treatment with TAA + C restored the aforementioned increased levels compared with the TAA group. In conclusion, treatment of rats with the combination of celecoxib and octreotide could attenuate the progress of hepatic fibrosis via protection of hepatocytes by reducing apoptosis, EMT and autophagy in hepatocytes.

Ethanol Extract of Liriope platyphylla Root Attenuates Non-Alcoholic Fatty Liver Disease in High-Fat Diet-Induced Obese Mice via Regulation of Lipogenesis and Lipid Uptake

Non-alcoholic fatty liver disease (NAFLD) is a common metabolic disorder that causes excess lipid accumulation in the liver and is the leading cause of end-stage liver disease. Liriope platyphylla is a medicinal herb that has long been used to treat cough, obesity, and diabetes. However, the effect of Liriope platyphylla on NAFLD has not been studied. The aim of this study was to investigate the effect of Liriope platyphylla root ethanolic extract (LPE) on hepatic lipid accumulation in high-fat diet (HFD)-induced obese mice. Six-week-old C57BL/6 male mice were fed a HFD for 8 weeks and then treated with LPE (100 or 250 mg/kg/day) by oral gavage for another 8 weeks. Body weight gain and liver weight were significantly lower in the 250 mg/kg LPE-treated HFD group than in the vehicle-treated HFD group. Histological analysis of liver sections demonstrated that LPE treatment reduced lipid accumulation compared to the vehicle treatment. The serum total cholesterol, AST, and ALT levels significantly decreased in the LPE-treated HFD group compared to those in the vehicle-treated HFD group. The LPE significantly decreases the protein expression levels of SREBP1, ACC, p-ACC, FAS, and SCD1, which are involved in lipogenesis, and PPARγ, CD36/FAT, and FATP5, which are involved in fatty acid uptake, both in vivo and in vitro. Thus, LPE may attenuate HFD-induced NAFLD by decreasing lipid accumulation by inhibiting lipogenesis and fatty acid uptake.

Inhibition of cyclooxygenase-2 enhanced intestinal epithelial homeostasis via suppressing β-catenin signalling pathway in experimental liver fibrosis

The intestinal barrier dysfunction is crucial for the development of liver fibrosis but can be disturbed by intestinal chronic inflammation characterized with cyclooxygenase‐2 (COX‐2) expression. This study focused on the unknown mechanism by which COX‐2 regulates intestinal epithelial homeostasis in liver fibrosis. The animal models of liver fibrosis induced with TAA were established in rats and in intestinal epithelial–specific COX‐2 knockout mice. The impacts of COX‐2 on intestinal epithelial homeostasis via suppressing β‐catenin signalling pathway were verified pharmacologically and genetically in vivo. A similar assumption was tested in Ls174T cells with goblet cell phenotype in vitro. Firstly, disruption of intestinal epithelial homeostasis in cirrhotic rats was ameliorated by celecoxib, a selective COX‐2 inhibitor. Then, β‐catenin signalling pathway in cirrhotic rats was associated with the activation of COX‐2. Furthermore, intestinal epithelial–specific COX‐2 knockout could suppress β‐catenin signalling pathway and restore the disruption of ileal epithelial homeostasis in cirrhotic mice. Moreover, the effect of COX‐2/PGE2 was dependent on the β‐catenin signalling pathway in Ls174T cells. Therefore, inhibition of COX‐2 may enhance intestinal epithelial homeostasis via suppression of the β‐catenin signalling pathway in liver fibrosis.

Involvement of TLR4 signaling regulated-COX2/PGE2 axis in liver fibrosis induced by Schistosoma japonicum infection

Background

Hepatic stellate cell (HSC) activation plays a pivotal role in hepatic inflammation and liver fibrosis. TLR4 pathway activation has been reported to be involved in mice liver fibrosis induced by hepatitis virus infection, alcohol abuse, biliary ligation, carbon tetrachloride 4 treatment, and Schistosoma japonicum (Sj) infection. The effect and mechanisms of the cyclooxygenase 2 (COX2)/prostanoid E2 (PGE2) axis on liver fibrosis induced by Sj are still unclear.

Methods

Mice liver fibrosis were induced by cutaneous infection of Sj cercariae. COX-2 inhibitor, NS398 were injected from week 5 to week 7, while TLR4 inhibitor TAK242 were injected from week 4 to week 8 post Sj infection. Human HSCs line, LX-2 cells were cultured and exposed to LPS or synthetic PGE2, or pretreated by TAK242, TLR4-siRNA or NS398. Liver tissue and serum or in vitro cultured cell lysaste were collected at indicated time courses for exploring the relationship between TLR4 and COX2-PGE2 axis through qPCR, western blot, immunohistochemical assay, ect. One-way analysis of variance among multiple groups followed by Uncorrected Fisher’s LSD-t test or paired comparisons through t test were performed to tell the statistical differences.

Results

This study investigated the link between the COX2/PGE2 axis and TLR4 signaling in the induction of liver fibrogenesis in mice during Sj infection and in vitro culture of HSC strain-LX-2. The COX2/PGE2 axis was positively associated with Sj-induced liver fibrosis. TLR4 pathway activation stimulated the COX2/PGE2 axis in Sj-infected mice and in lipopolysaccharide (LPS)-exposed cultured HSCs. Synthetic PGE2 activated cultured HSCs through upregulation of alpha smooth muscle actin (α-SMA) expression. In LPS-triggered HSCs, NS398, a COX2 inhibitor, led to suppression of PGE2 synthesis and reduced expression of α-SMA and type I collagen (COL I).

Conclusions

These results indicate firstly the positive association of the COX2/PGE2 axis with liver fibrosis induced by Sj infection. TLR4 signaling may at least partially control the COX2/PGE2 axis in Sj-infected mice liver and in vitro cultured HSCs. The COX2/PGE2-EP2/EP4 axis might be a good drug target against liver fibrosis induced by Sj infection.

Graphic abstract

Celecoxib ameliorates liver cirrhosis via reducing inflammation and oxidative stress along spleen-liver axis in rats

BACKGROUND & AIMS

Splenomegaly is usually taken as a consequence of liver cirrhosis. However, as a risk factor for cirrhosis, the impacts of spleen-liver axis on the development of cirrhosis are largely unknown. This study focused on the impacts of splenomegaly on the development of cirrhosis and assessment of the effects of celecoxib, a selective COX-2 inhibitor, on the splenomegaly and cirrhotic liver.

MATERIALS AND METHODS

Liver cirrhosis was induced by thioacetamide (TAA). Sixty rats were randomly divided into control, TAA-16w, TAA + celecoxib groups and normal, TAA + sham, TAA + splenectomy groups. Hepatic stellate cells (HSCs) or hepatocytes were co-cultured with splenocytes from those groups.

RESULTS

Splenocytes of cirrhotic rats stimulated the HSCs activation and induced hepatocyte apoptosis via enhancing oxidative stress. The hepatic levels of NOX-4 and the in situ O₂^- were profoundly reduced in TAA + splenectomy group by 50.6% and 18.5% respectively, p < 0.05. Celecoxib significantly decreased the hepatic fibrotic septa induced with TAA by 50.8%, p < 0.05. Splenic lymphoid tissue proliferation and proinflammatory cytokines of the cirrhotic rats were also obviously suppressed by celecoxib, p < 0.05. Compared with the HSC or hepatocyte cell line co-cultured with the cirrhotic splenocytes, the expression of alpha-SMA, NOX-4, in situ O₂^- or the levels of cleaved caspase3 and NOX-4 were significantly decreased in those cell lines co-cultured with cirrhotic splenocytes treated by celecoxib, p < 0.05.

CONCLUSION

Splenomegaly contributed to the development of liver cirrhosis through enhancing oxidative stress in liver. Celecoxib could effectively ameliorate liver cirrhosis via reducing inflammatory cytokines and immune cells derived from spleen and suppressing oxidative stress.

Gut-Pancreas-Liver Axis as a Target for Treatment of NAFLD/NASH

Non-alcoholic fatty liver disease (NAFLD) represents the most common form of chronic liver disease worldwide. Due to its association with obesity and diabetes and the fall in hepatitis C virus morbidity, cirrhosis in NAFLD is becoming the most frequent indication to liver transplantation, but the pathogenetic mechanisms are still not completely understood. The so-called gut-liver axis has gained enormous interest when data showed that its alteration can lead to NAFLD development and might favor the occurrence of non-alcoholic steatohepatitis (NASH). Moreover, several therapeutic approaches targeting the gut-pancreas-liver axis, e.g., incretins, showed promising results in NASH treatment. In this review, we describe the role of incretin hormones in NAFLD/NASH pathogenesis and treatment and how metagenomic/metabolomic alterations in the gut microbiota can lead to NASH in the presence of gut barrier modifications favoring the passage of bacteria or bacterial products in the portal circulation, i.e., bacterial translocation.

Role of arachidonic acid-derived eicosanoids in intestinal innate immunity

Arachidonic acid (ARA), an n-6 essential fatty acid, plays an important role in human and animal growth and development. The ARA presents in the membrane phospholipids can be released by phospholipase A2. These free arachidonic acid molecules are then used to produce eicosanoids through three different pathways. Previous studies have demonstrated that eicosanoids have a wide range of physiological functions. Although they are generally considered to be pro-inflammatory molecules, recent advances have elucidated they have an effect on innate immunity via regulating the development, and differentiation of innate immune cells and the function of the intestinal epithelial barrier. Here, we review eicosanoids generation in intestine and their role in intestinal innate immunity, focusing on intestinal epithelial barrier, innate immune cell in lamina propria (LP) and their crosstalk.

Lipid mechanisms in hallmarks of cancer

Excess adiposity is a risk factor for several cancer types. This is likely due to complex mechanisms including alterations in the lipid milieu that plays a pivotal role in multiple aspects of carcinogenesis. Here we consider the direct role of lipids in regulating well-known hallmarks of cancer. Furthermore, we suggest that obesity-associated remodelling of membranes and organelles drives cancer cell proliferation and invasion. Identification of cancer-related lipid-mediated mechanisms amongst the broad metabolic disturbances due to excess adiposity is central to the identification of novel and more efficacious prevention and intervention strategies.

Dietary α-Lactalbumin protects against thioacetamide-induced liver cirrhosis by maintaining gut-liver axis function in rats

We tested the hypothesis that α-lactalbumin inhibits the disruption of intestinal barrier function and liver cirrhosis by restoring gut-liver axis function in thioacetamide (TAA) -treated rats. Rat diets were supplemented with α-lactalbumin replacing 50% of dietary protein. After consuming α-lactalbumin for one week, rats were intraperitoneally injected with TAA twice a week for 14 weeks. The α-lactalbumin-enriched diet significantly inhibited the elevation of plasma alanine aminotransferase, aspartate aminotransferase, and hyaluronic acids. The supplement significantly reduced plasma lipopolysaccharide levels and increased occludin mRNA level. Hepatic fibrosis and regenerative nodules was developed and intestinal villi were shortened by TAA; α-Lactalbumin attenuated these histopathological changes. These results indicated that α-lactalbumin improved intestinal barrier function, suppressing endotoxin levels. These data also suggested that α-lactalbumin ameliorated the impairment of the gut-liver axis by TAA, inhibiting the development of liver cirrhosis.

Suppressing growth and invasion of human hepatocellular carcinoma cells by celecoxib through inhibition of cyclooxygenase-2

Purpose: Biomarkers are lacking in hepatocellular carcinoma (HCC). Cyclooxygenase-2 (COX-2) and its metabolites play crucial roles in the process of inflammation-tumor transformation. This study was aimed to detect COX-2 expression in HCC tissues and evaluate the effects of a COX-2 inhibitor, celecoxib, on biological behaviors of HCC cell lines in vitro.

Methods: COX-2 expression was detected by immunohistochemistry on a human HCC tissue microarray. The correlations of COX-2 expression with tumor clinicopathological variables and overall survival were analyzed. The proliferation, apoptosis, cell cycle distribution, invasion capacity, and related signaling molecules of HCC cells after incubated with COX-2 inhibitor celecoxib were evaluated in vitro.

Results: Expression levels of COX-2 in HCC tissues were significantly higher than those in paracancerous tissues. The TNM stage III-IV, tumor size >5 cm, lymphovascular invasion and distant metastasis was higher in high COX-2 expression group compared with that in low COX-2 expression group. Patients with low COX-2 expression achieved better 5-year overall survival than those with high COX-2 expression. Treatment with celecoxib was sufficient to inhibit cell proliferation, promote apoptosis, and induce G0/G1 cell cycle arrest in HCC cells with concentration- and time-dependent manners. Celecoxib up-regulated E-cadherin protein through inhibiting COX-2-prostaglandin E2 (PGE2)-PGE2 receptor 2 (EP2)-p-Akt/p-ERK signaling pathway to suppress HCC cells migration and invasion.

Conclusion: High COX-2 expression was associated with advanced TNM stage, larger tumor size, increased lymphovascular invasion and short survival. Targeting inhibition of COX-2 by celecoxib exhibited anti-tumor activities by suppressing proliferation, promoting apoptosis, and inhibiting the aggressive properties of HCC cells.

Mechanistic insights to the cardioprotective effect of blueberry nutraceutical extract in isoprenaline-induced cardiac hypertrophy

BACKGROUND

Lowbush blueberry extract (Vaccinium angustifolium) is abundant with polyphenols (such as chlorogenic acid) with high antioxidant profile. It has received great interest due to its protective role in many disorders such as heart diseases and neurological disorders.

HYPOTHESIS

We hypothesized that blueberry leaf extract might have a protective effect against cardiac hypertrophy via suppressing oxidative stress, inflammation and fibrosis.

METHOD

Blueberry leaf nutraceutical extract was administered orally to male albino rats at three different doses (25, 50 and 100 mg/kg/day of the extract, equivalent to 3.4, 6.8 and 13.6 mg of chlorogenic acid, respectively) once daily for 28 consecutive days against a dose of isoprenaline (ISO) (5 mg/kg) for 14 days.

RESULTS

The results indicated that isoprenaline induced significant myocardial damage, characterized by conduction abnormalities, increased heart-to-body weight ratio, increased serum CKMB, AST, c-TnI and LDH. Pretreatment with blueberry extract at a dose of 50 mg/kg/day (equivalent to 6.8 mg chlorogenic acid) protected against ISO-induced ECG changes, leakage of cardiac enzymes and histopathological changes. Also, ISO caused significant glutathione depletion, lipid peroxidation and reduction in activities of antioxidant catalase enzyme. These effects were prevented by pretreatment with blueberry extract. Additionally, ISO elicited inflammatory effects by increasing the expression of NF-κB, COX-2, TNF-α and IL-6 while pretreatment with blueberry extract significantly inhibited these inflammatory responses. Furthermore, ISO induced fibrosis by increasing the level of TGF-β while pretreatment with blueberry extract significantly reduced it.

CONCLUSION

These findings indicate that blueberry leaf extract possessed a potent protective effect against ISO-induced cardiac hypertrophy via suppressing oxidative stress, inflammation and fibrosis.

Cyclooxygenase-2 up-regulates hepatic somatostatin receptor 2 expression

Somatostatin and its analogues, which function by binding to somatostatin receptors (SSTRs) 1-5, play a protective role in liver cirrhosis. Hepatic SSTR-2 expression is up-regulated in subjects with liver cirrhosis. However, little is known about the mechanisms underlying this process. In the present study, we observed the up-regulation of hepatic SSTR-2 expression in thioacetamide (TAA)-induced cirrhotic rats and further showed that cyclooxygenase-2 (COX-2) might play a role in this process via the protein kinase C (PKC)-cAMP response element binding protein (CREB) signaling pathway. In vivo, the up-regulated SSTR-2 in liver cirrhosis was inhibited by the addition of a selective COX-2 inhibitor, such as celecoxib. In vitro, the up-regulation of COX-2 by either transfection with COX-2 plasmids or treatment with TAA increased levels of SSTR-2 and phosphorylated CREB (p-CREB) in the human hepatocyte cell line L02. Furthermore, the increase in SSTR-2 expression was inhibited by the addition of celecoxib and a PKC inhibitor. Moreover, for comparable DNA methylation levels in the region upstream of the hepatic SSTR-2 gene in normal and cirrhotic livers, DNA methylation may not contribute to the up-regulation of SSTR-2 expression in cirrhotic livers. In conclusion, the up-regulation of hepatic SSTR-2 might be induced by COX-2 via the PKC-CREB signaling pathway but is probably not induced by DNA methylation.

Adjuvant celecoxib and lanreotide following transarterial chemoembolisation for unresectable hepatocellular carcinoma: a randomized pilot study

Recurrence of hepatocellular carcinoma (HCC) after transarterial chemoembolisation (TACE) is common due to neoangiogenesis. Cyclooxygenase-2 inhibitors and somatostatin analogues were reported to inhibit tumour angiogenesis. The pilot randomized controlled trial was aimed to prospectively evaluate the protocol of TACE combined with celecoxib and lanreotide (TACE+C+L) in patients with unresectable and advanced HCC. A total of 71 patients with HCC were enrolled and randomly assigned to either TACE (n=35) or TACE+C+L (n=36) group. Overall survival, disease control rate (DCR), and adverse events were assessed during a 3-year follow-up period. The median overall survival of the TACE+C+L group (15.0 months) was doubled compared to that of TACE group (7.5 months), p = 0.012. DCR of the TACE+C+L group was significantly higher than that of the TACE group either at 6 months (72.2% vs 42.9%, p = 0.012) or at 12 months (61.1% vs 28.6%, p = 0.006). The median overall survivals (13 months vs 4.5 months, p = 0.013) and DCR at 12 months (50% vs 13.6%, p = 0.008) of patients with advanced HCC in TACE+C+L groups were significantly higher than those in TACE group. No significant difference of adverse events was observed between the two groups. The occurrence of post-embolisation syndrome in TACE+C+L group was significantly lower than that in TACE group (16.7% vs 60.0%, p = 0.001). In conclusion, the regimen of TACE+C+L prolonged overall survival, enhanced tumour response, reduced post-embolisation syndrome and was well-tolerable in the patients with unresectable HCC. It may be more beneficial for advanced HCC.

Elevated systemic zonula occludens 1 is positively correlated with inflammation in cirrhosis

BACKGROUND/AIM

It has been well established that disruption of the intestinal barrier function and increased intestinal permeability contribute to endotoxemia and associated liver injury in patients with cirrhosis. However, the relationship between systemic inflammation and tight junction protein in cirrhosis remain unidentified. The aim of this study was to assess and compare the blood concentrations of ZO-1 with systemic hsCRP in patients with cirrhosis and healthy individuals.

METHODS

30 cirrhotic patients and 30 healthy individuals were enrolled in the study. Blood ZO-1 and hsCRP were measured by ELISA and biochemical parameters by AU680 Beckman Coulter (USA) autoanalyser.

RESULTS

The serum ALT, AST, bilirubin, gamma GT, ALP and ammonia were significantly (P < 0.0001) elevated whilst serum albumin concentration was decreased in cirrhotic patients when compared to healthy individuals. Systemic tight junction protein ZO-1 concentration [590.0 ± 32.79 vs. 349.9 ± 18.76 pg/ml, respectively; P < 0.0001] and hsCRP [10.50 ± 1.05 vs 5.31 ± 0.65 mg/L, respectively; P < 0.001] were significantly elevated in patients with cirrhosis compared to controls. Significant positive correlation was found between increased ZO-1 and hsCRP (r = 0.2680 P < 0.01).

CONCLUSION

Our results suggested that increased systemic ZO-1 concentration was associated with inflammation in cirrhosis. Thus, elevated blood ZO-1 levels could be a prognostic marker of cirrhotic patients with intestinal TJ disruption on the background of inflammation.

Role of cyclooxygenase-2 in immune response in liver fibrosis and mechanisms involved

Cyclooxygenase-2 (COX-2), an inducible enzyme, is almost not expressed in normal human and rat liver tissues, but is highly expressed in liver tissues of patients with chronic hepatitis and cirrhosis. Inhibition or interference of COX-2 expression can significantly inhibit the formation of hepatic fibrosis in rats, suggesting that COX-2 is involved in the occurrence and development of hepatic fibrosis; however, the underlying mechanism is unclear. Recent studies have shown that the role of COX-2 in the development of hepatic fibrosis may be related to immune response. In this paper, we review the role of COX-2 and its metabolites in the immune response in liver fibrosis, with an aim to provide a theoretical basis for clinical prevention and treatment of hepatic fibrosis.