Protective effects of BML-111 against acetaminophen-induced acute liver injury in mice

A cross-talk between sestrins, chronic inflammation and cellular senescence governs the development of age-associated sarcopenia and obesity

The rapid increase in both the lifespan and proportion of older adults is accompanied by the unprecedented rise in age-associated chronic diseases, including sarcopenia and obesity. Aging is also manifested by increased susceptibility to multiple endogenous and exogenous stresses enabling such chronic conditions to develop. Among the main physiological regulators of cellular adaption to various stress stimuli, such as DNA damage, hypoxia, and oxidative stress, are sestrins (Sesns), a family of three evolutionarily conserved proteins, Sesn1, 2, and 3. Age-associated sarcopenia and obesity are characterized by two key processes: (i) accumulation of senescent cells in the skeletal muscle and adipose tissue and (ii) creation of a systemic, chronic, low-grade inflammation (SCLGI). Presumably, failed SCLGI resolution governs the development of these chronic conditions. Noteworthy, Sesns activate senolytics, which are agents that selectively eliminate senescent cells, as well as specialized pro-resolving mediators, which are factors that physiologically provide inflammation resolution. Sesns reveal clear beneficial effects in pre-clinical models of sarcopenia and obesity. Based on these observations, we propose a novel treatment strategy for age-associated sarcopenia and obesity, complementary to the conventional therapeutic modalities: Sesn activation, SCLGI resolution, and senescent cell elimination.

Eicosanoids and other oxylipins in liver injury, inflammation and liver cancer development

Liver cancer is a malignancy developed from underlying liver disease that encompasses liver injury and metabolic disorders. The progression from these underlying liver disease to cancer is accompanied by chronic inflammatory conditions in which liver macrophages play important roles in orchestrating the inflammatory response. During this process, bioactive lipids produced by hepatocytes and macrophages mediate the inflammatory responses by acting as pro-inflammatory factors, as well as, playing roles in the resolution of inflammation conditions. Here, we review the literature discussing the roles of bioactive lipids in acute and chronic hepatic inflammation and progression to cancer.

Formyl peptide receptor 2 is an emerging modulator of inflammation in the liver

Formyl peptide receptors (FPRs), which are seven-membrane G-protein coupled receptors, recognize chemotactic signals to protect hosts from pathogenic infections and mediate inflammatory responses in the body. There are three isoforms of FPRs in humans-FPR1, FPR2, and FPR3-and they bind to N-formyl peptides, except FPR3, and to various endogenous agonists. Among FPR family members, FPR2 has a lower affinity for N-formyl peptides than FPR1 and binds with a wide range of endogenous or exogenous agonists. Thus, FPR2 is considered the most ambiguous member. Accumulating evidence has shown that FPR2 is involved in the host's defense against bacterial infection and inflammation in liver diseases, such as nonalcoholic fatty liver disease, liver fibrosis, and liver cancer, suggesting the pathophysiological relevance of FPR2 to the liver. However, FPR2 has been shown to promote or suppress inflammation, depending on the type of FPR2-expressing cell and FPR2-bound ligands in the liver. Therefore, it is important to understand FPR2's function per se and to elucidate the mechanism underlying immunomodulation initiated by ligand-activated FPR2 before suggesting FPR2 as a novel therapeutic agent for liver diseases. In this review, up-to-date knowledge of FPR2, with general information on the FPR family, is provided. We shed light on the dual action of FPR2 in the liver and discuss the hepatoprotective roles of FPR2 itself and FPR2 agonists in mediating anti-inflammatory responses.

The Lipoxin Receptor/FPR2 Agonist BML-111 Protects Mouse Skin Against Ultraviolet B Radiation

Excessive exposure to UV, especially UVB, is the most important risk factor for skin cancer and premature skin aging. The identification of the specialized pro-resolving lipid mediators (SPMs) challenged the preexisting paradigm of how inflammation ends. Rather than a passive process, the resolution of inflammation relies on the active production of SPMs, such as Lipoxins (Lx), Maresins, protectins, and Resolvins. LXA4 is an SPM that exerts its action through ALX/FPR2 receptor. Stable ALX/FPR2 agonists are required because SPMs can be quickly metabolized within tissues near the site of formation. BML-111 is a commercially available synthetic ALX/FPR2 receptor agonist with analgesic, antioxidant, and anti-inflammatory properties. Based on that, we aimed to determine the effect of BML-111 in a model of UVB-induced skin inflammation in hairless mice. We demonstrated that BML-111 ameliorates the signs of UVB-induced skin inflammation by reducing neutrophil recruitment and mast cell activation. Reduction of these cells by BML-111 led to lower number of sunburn cells formation, decrease in epidermal thickness, collagen degradation, cytokine production (TNF-α, IL-1β, IL-6, TGF, and IL-10), and oxidative stress (observed by an increase in total antioxidant capacity and Nrf2 signaling pathway), indicating that BML-111 might be a promising drug to treat skin disorders.

Impact of date palm pollen (Phoenix dactylifera) treatment on paracetamol-induced hepatorenal toxicity in rats

Background

Consumption of plant-derived nutraceuticals and crude drugs in Arab traditional medicine is widely believed to confer beneficial effects in liver and kidney diseases. Fruits from the date palm Phoenix dactylifera L. are a rich source of nutrients and bioactive phytochemicals which possess a myriad of pharmacological effects. Herein, we examined the impact of Date Palm Pollen (DPP) aqueous suspension treatment on paracetamol (APAP) [Acetaminophen (APAP)] triggered hepatorenal damage in rats and further explored the underlying putative mechanism.

Methods

Thirty Wistar rats were assigned to five groups (n = 6/group). Group I was control group; animals in group II were administered APAP 1000 mg/kg body weight (b.w.) intraperitonealy (i.p.); Group III and IV administered APAP plus date palm pollen with doses of 50, 100 mg/kg b.w and group V were administered APAP plus Silymarin (SIL) 10 mg/kg b.w. (i.p) respectively. Various biochemical parameters and histological assessment were evaluated in serum and tissue homogenate.

Results

Pretreatment with DPP aqueous suspensions (50 and 100 mg/kg b.w.) significantly (p < 0.05) thwarted APAP triggered alterations in serum biomarkers of liver damage [aspartate transaminase (AST), alanine aminotransferase (ALT), γ-glutamyl transferase (GGT) and alkaline phosphatase (ALP)], serum albumin as well as bilirubin. DPP treatment further mitigated APAP triggered dyslipidemia associated with hepatic damage by influencing APAP elicited changes in serum levels of cholesterol, triglycerides, HDL, LDL and VLDL. DPP treatment significantly (p < 0.05) ameliorated extrahepatic manifestations of APAP toxicity by influencing alterations in parameters of renal function (creatinine, urea and uric acid) as well serum electrolytes (Sodium, Potassium and Calcium). DPP treatment further influenced APAP-induced histological lesions by curtailing necrosis and inflammatory changes in the hepatic and renal architecture, respectively. Furthermore, DPP treatment modulated APAP-induced redox imbalance in the hepatic and renal tissue by blunting the increase of malondialdehyde (MDA) as well as decrease of nonprotein sulfhydryls (NP-SH) significantly (p < 0.05) when compared with control. The protective effect of DPP was further confirmed histologically.

Conclusions

The present observations point to an hepatorenal protective effects of acute DPP treatment in APAP-intoxicated rats which is underpinned by its robust antioxidant properties.

Polydatin protects against acetaminophen-induced hepatotoxicity in mice via anti-oxidative and anti-apoptotic activities

Polydatin protects against acetaminophen-induced hepatotoxicity in mice.

Protective activity of tovophyllin A, a xanthone isolated from Garcinia mangostana pericarps, against acetaminophen-induced liver damage: role of Nrf2 activation

Tovophyllin A (TA) ameliorates APAP-induced hepatotoxicity by activating Nrf2 and inhibiting the NF-κB pathway.

Beneficial effects of rosmarinic acid against alcohol-induced hepatotoxicity in rats

Alcohol is a severe hepatotoxicant that causes a variety of liver disorders. Rosmarinic acid (RA), a natural phenol, shows some biological activities, including antioxidant and anti-inflammatory effects. We investigated the effects of RA (10 mg/kg) against ethanol-induced oxidative damage and hepatotoxicity in rats. Animals received ethanol (4 g/kg, i.g.) and (or) RA (10 mg/kg, i.g.) daily for 4 weeks. At the end of the treatment period, rats were weighed and use for biochemical, molecular, and histopathological examinations. Ethanol increased hepatic lipid peroxidation (P < 0.001) and decreased hepatic levels of reduced glutathione (P < 0.01), catalase (P < 0.05), and superoxide dismutase (P < 0.001) compared with control group. RA prevented the prooxidant and antioxidant imbalance induced by ethanol in liver. Furthermore, RA ameliorated the increased liver mass, serum levels of ALT, AST, LDH, TNF-α, and IL-6 in ethanol group. Necrosis and infiltration of inflammatory cells in liver parenchyma were attenuated by RA treatment. Our findings showed that RA prevents ethanol-induced oxidant/antioxidant imbalance and liver injury in an experimental model of ethanol-induced hepatotoxicity. Therefore, RA may be a good candidate to protect against ethanol-induced hepatotoxicity; this deserves consideration and further examination.

Effects of rosmarinic acid on acetaminophen-induced hepatotoxicity in male Wistar rats

CONTEXT

Drug-induced liver injury is a significant worldwide clinical problem. Rosmarinic acid (RA), a natural phenol, has antioxidant effects.

OBJECTIVE

The effects of RA against acetaminophen (N-acetyl-p-amino-phenol (APAP))-induced oxidative damage and hepatotoxicity in rats were investigated.

MATERIALS AND METHODS

Male Wistar rats were pretreated with RA (10, 50 and 100 mg/kg, i.g.) for one week. On day 7, rats received APAP (500 mg/kg, i.p.). Then aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, total protein, malondialdehyde (MDA), glutathione (GSH), total antioxidant capacity (TAC), glutathione S-transferase (GST), cytochrome CYP450 and histopathological changes were determined.

RESULTS

APAP-induced oxidative stress in liver by a significant increase in the level of MDA (7.6 ± 0.21 nmol/mg) as well as a decrease in the contents of TAC (1.75 ± 0.14 μmol/g), GSH (1.9 ± 0.22 μmol/g) and GST) 3.2 ± 0.28 U/mg). RA treatment decreased MDA (4.32 ± 0.35 nmol/mg) but increased the contents of TAC (3.51 ± 0.34 μmol/g), GSH (3.42 ± 0.16 μmol/g) and GST (5.71 ± 0.71 μmol/g) in APAP group. RA 100 mg/kg decreased ALT (91.5 ± 1.5 U/L), AST (169 ± 8.8 U/L) and CYP450 (3 ± 0.2 nmol/min/mg) in APAP group. Histologically RA attenuated hepatic damage by decreasing necrosis, inflammation, and haemorrhage in liver sections of APAP group.

DISCUSSION AND CONCLUSIONS

This is the first report that oral administration of RA dose-dependently elicited significant hepatoprotective effects in rats through inhibition of hepatic CYP2E1 activity and lipid peroxidation. RA-protected hepatic GSH and GST reserves and total tissue antioxidant capacity.

Pirfenidone ameliorates concanavalin A-induced hepatitis in mice via modulation of reactive oxygen species/nuclear factor kappa B signalling pathways

Objectives

This study aimed to evaluate the potential protective effects of pirfenidone (PFD) against concanavalin A (Con A)-induced hepatitis in mice.

Methods

Autoimmune model of hepatitis was established using single intravenous injection of Con A. Mice were randomly assigned into four groups as follows: control group; Con A group; and two groups, receiving PFD in two dose levels (200, 300 mg/kg) for 5 days before Con A administration. Extent of hepatitis was studied using biochemical, histopathological and immunohistochemical estimations.

Key findings

Hepatitis was clearly evident through extensive hepatocellular lesions and elevated levels of serum transaminases, alkaline phosphatase and lactate dehydrogenase. Con A induced an imbalance between oxidant and antioxidant status in the hepatic tissue. Furthermore, Con A significantly elevated hepatic nuclear factor kappa B (NF-κB) expression and inflammatory cytokines levels (tumour necrosis factor-alpha, interleukin-6 and nitric oxide). PFD pretreatment potently ameliorated all these pathological changes.

Conclusions

Pirfenidone hepatoprotective activity may be mediated through its antioxidant ability that suppresses NF-κB activation signalling pathways suggesting that PFD may be a new candidate for treatment of acute hepatitis.

BML-111 Protected LPS/D-GalN-Induced Acute Liver Injury in Rats

Lipoxins (LXs) display unique pro-resolving and anti-inflammatory functions in a variety of inflammatory conditions. The present study was undertaken to investigate the effects of BML-111 (5(S),6(R),7-trihydroxyheptanoic acid methyl ester), the agonist of lipoxin A₄ receptor, in a model of Lipopolysaccharides (LPS) and d-Galactosamine (d-GalN) induced acute liver injury, and to explore the mechanisms. Histopathological analyses were carried out to quantify liver injury degree. The activities of myeloperoxidase (MPO) were examined to evaluate the levels of neutrophil infiltration. The activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum were detected to evaluate the functions of the liver. The amounts of tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), and interleukin-1β (IL-1β) were measured using enzyme-linked immunosorbent assay (ELISA), and the expression levels of transforming growth factor-β1(TGF-β1) and cyclooxygenase-2 (COX-2) were examined using Western blotting. The antioxidant capacity, the activities of inducible nitric oxide synthase (iNOS), the contents of malondialdehyde (MDA) and nitric oxide (NO) were analyzed with the kits via biochemical analysis. We established the model of acute liver injury with lipopolysaccharide and d-Galactosamine (LPS/d-GalN): (1) histopathological results and MPO activities, with the activities of AST and ALT in serum, consistently demonstrated LPS and d-GalN challenge could cause severe liver damage, but BML-111 could prevent pathological changes, inhibit neutrophil infiltration, and improve the hepatic function; (2) LPS/d-GalN increased TNF-α, IL-1β, COX-2, and IL-10, while decreasing TGF-β1. However, BML-111 could repress LPS/d-GalN -induced TNF-α, IL-1β and COX-2, meanwhile increasing the expression levels of TGF-β1 and IL-10; (3) LPS/d-GalN inhibited the activities of superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (T-AOC), and hydroxyl radical-scavenging ability, simultaneously increasing the levels of MDA and NO, so also the activity of iNOS. Otherwise, BML-111 could reverse all the phenomena. In a word, BML-111 played a protective role in acute liver injury induced by LPS and d-GalN in rats, through improving antioxidant capacity and regulating the balance of inflammatory cytokines.

Effects of isoquinoline alkaloid berberine on lipid peroxidation, antioxidant defense system, and liver damage induced by lead acetate in rats

OBJECTIVES

Liver is considered a target organ affected by lead toxicity. Oxidative stress is among the mechanisms involved in liver damage. Here we investigated the effects of the natural alkaloid berberine on oxidative stress and hepatotoxicity induced by lead in rats.

METHODS

Animals received an aqueous solution of lead acetate (500 mg Pb/l in the drinking water) and/or daily oral gavage of berberine (50 mg/kg) for 8 weeks. Rats were then weighed and used for the biochemical, molecular, and histological evaluations.

RESULTS

Lead-induced oxidative stress, shown by increasing lipid peroxidation along with a concomitant decrease in hepatic levels of thiol groups, total antioxidant capacity, the activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione-S-transferase, and reduced versus oxidized glutathione ratio. Berberine corrected all the disturbances in oxidative stress markers induced by lead administration. Berberine also prevented the elevated levels of enzymes (alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase) and the decrease in body weight and albumin. The protective effects of berberine were comparable with silymarin. Furthermore, berberine attenuated liver damage, shown by decreased necrosis and inflammatory cell infiltration.

DISCUSSION

Berberine represents a potential therapeutic option against lead-induced hepatotoxicity through inhibiting lipid peroxidation and enhancing antioxidant defenses.

CONCLUSION

Berberine exerted protective effects on lead-induced oxidative stress and hepatotoxicity in rats.

Lipoxin A4 exerts protective effects against experimental acute liver failure by inhibiting the NF-κB pathway

Although rare, acute liver failure (ALF) is associated with high levels of mortality, warranting the development of novel therapies. Nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) play roles in ALF. Lipoxin A4 (LXA4) has been shown to alleviate inflammation in non-hepatic tissues. In the present study, we explored whether LXA4 exerted hepatoprotective effects in a rat model of ALF. A rat model of ALF was generated by intraperitoneal injections of D-galactosamine (300 mg/kg) and lipopolysaccharide (50 µg/kg). Animals were randomly assigned to: control group (no ALF); model group (ALF); and the groups treated with a low dose (0.5 µg/kg), medium dose (1 µg/kg), and high dose (2 µg/kg) of LXA4 (all with ALF); and pyrrolidine dithiocarbamate (PDTC)-treated group (ALF and 100 mg/kg PDTC, an inhibitor of NF-κB). Liver histology was measured using H&E staining, serum levels by ELISA, and liver mRNA expression was measured by RT-PCR for the detection of the pro‑inflammatory cytokines TNF-α and IL-6. Liver cell apoptosis (as measured using the TUNEL method and examining caspase-3 activity), and Kupffer cell NF-κB activity [using an electrophoretic mobility shift assay (EMSA)] were examined. Serum levels of transaminases, TNF-α and interleukin-6 (IL-6) were substantially higher in the model group compared to controls. In the model group, significant increases in TNF-α and IL-6 mRNA expression, TUNEL‑positive cells, and caspase-3 activity in the liver tissue were noted. LXA4 improved liver pathology and significantly decreased the indicators of inflammatory response and apoptosis in a dose-dependent manner. High-dose LXA4 provided better protection than PDTC. LXA4 administration significantly decreased NF-κB expression in hepatocytes and Kupffer cells. These results indicated that LXA4 inhibited NF-κB activation, reduced the secretion of pro-inflammatory cytokines, and inhibited apoptosis of liver cells, thereby exerting protective effects against ALF.

Effect of BML-111 on the intestinal mucosal barrier in sepsis and its mechanism of action

5(S),6(R)-7-trihydroxymethyl heptanoate (BML-111) is an lipoxin A4 receptor agonist, which modulates the immune response and attenuates hemorrhagic shock-induced acute lung injury. However, the role of BML-111 in sepsis and in the intestinal mucosal barrier are not well understood. Therefore, the present study was designed to investigate the effect of BML-111 on the intestinal mucosal barrier in a rat model of sepsis. Furthermore, the molecular mechanism of action of BML-111 was evaluated. The cecal ligation and puncture-induced rat model of sepsis was constructed, and BML-111 was administered at three different doses. The results revealed that BML-111 suppressed the elevation of the pro-inflammatory cytokines tumor necrosis factor-α and interleukin-6, while enhancing the elevation of the anti-inflammatory cytokine transforming growth factor-β in the intestine. In addition, BML-111 significantly upregulated rat defensin-5 mRNA expression levels and downregulated the induction of cell apoptosis as well as caspase-3 activity in the intestine. All these results demonstrated that BML-111 exerted protective effects on the intestinal mucosal barrier in sepsis. Further, it was indicated that alterations in the expression of toll-like receptor (TLR)2 and TLR4 may be one of the molecular mechanisms underlying the protective effect of BML-111. The present study therefore suggested that BML-111 may be a novel therapeutic agent for sepsis.

A novel role of kukoamine B: Inhibition of the inflammatory response in the livers of lipopolysaccharide-induced septic mice via its unique property of combining with lipopolysaccharide

Kukoamine B (KB), derived from the traditional Chinese herb cortex Lycii, exerts anti-inflammatory effects due to its potent affinity with lipopolysaccharide (LPS) and CpG DNA; however, little is known regarding whether the in vivo administration of KB can effectively inhibit inflammation in septic mice. The present study thus aimed to investigate the inhibitory effects of KB on the inflammatory response in the livers of LPS-induced septic mice. KB treatment in the LPS-induced septic mice significantly decreased the plasma level of LPS. In addition, KB protected against liver injury, as confirmed by improved histology and decreased aminotransferase levels in the serum. Further experiments revealed that KB attenuated liver myeloperoxidase activity and reduced the expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1. These effects were accompanied by decreases in the levels of tumor necrosis factor α and interleukin-1β in the liver tissue. In parallel, the activity of nuclear factor-κ-gene binding (NF-κB) in the livers of LPS-induced septic mice was markedly inhibited with KB treatment. In combination, these results demonstrate that KB inhibits inflammation in septic mice by reducing the concentrations of plasma LPS, decreasing leukocyte sequestration and interfering with NF-κB activation, and, therefore, suppressing the pro-adhesive phenotype of endothelial cells.