Phycocyanobilin accelerates liver regeneration and reduces mortality rate in carbon tetrachloride-induced liver injury mice

Role of Natural Compounds Modulating Heme Catabolic Pathway in Gut, Liver, Cardiovascular, and Brain Diseases

The crucial physiological process of heme breakdown yields biliverdin (BV) and bilirubin (BR) as byproducts. BV, BR, and the enzymes involved in their production (the "yellow players-YP") are increasingly documented as endogenous modulators of human health. Mildly elevated serum bilirubin concentration has been correlated with a reduced risk of multiple chronic pro-oxidant and pro-inflammatory diseases, especially in the elderly. BR and BV per se have been demonstrated to protect against neurodegenerative diseases, in which heme oxygenase (HMOX), the main enzyme in the production of pigments, is almost always altered. HMOX upregulation has been interpreted as a tentative defense against the ongoing pathologic mechanisms. With the demonstration that multiple cells possess YP, their propensity to be modulated, and their broad spectrum of activity on multiple signaling pathways, the YP have assumed the role of an adjustable system that can promote health in adults. Based on that, there is an ongoing effort to induce their activity as a therapeutic option, and natural compounds are an attractive alternative to the goal, possibly requiring only minimal changes in the life style. We review the most recent evidence of the potential of natural compounds in targeting the YP in the context of the most common pathologic condition of adult and elderly life.

Human Umbilical Cord Blood Mononuclear Cells Ameliorate CCl4-Induced Acute Liver Injury in Mice via Inhibiting Inflammatory Responses and Upregulating Peripheral Interleukin-22

Background: Human umbilical cord blood mononuclear cells (hUCBMNCs) show therapeutic effects on many inflammatory diseases. The deterioration of acute liver injury is attributed to excessive inflammatory responses triggered by damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs). Whether hUCBMNCs treatment is a promising strategy for acute liver injury/failure needs to be investigated.

Methods: Liver injury mice induced by PAMPs, DAMPs, or DAMPs plus PAMPs were developed. DAMPs included CCl4 (carbon tetrachloride), APAP (acetaminophen), and ConA (Concanavalin A). PAMPs included Klebsiella pneumoniae (K.P.) and Salmonella typhimurium (S. Typhimurium). DAMP plus PAMP-induced liver injury was developed by sequential CCl4 and K.P. administration. hUCBMNCs were injected intravenously.

Results: hUCBMNCs significantly prolonged mice survival time in DAMP plus PAMP-induced liver failure but had no benefit in bacteria-infected mice. hUCBMNCs significantly alleviated hepatic necrosis post CCl4/ConA insult. In CCl4-induced acute liver injury, peripheral levels of interleukin (IL)-22 were upregulated and liver regeneration was enhanced after treating with hUCBMNCs at 48h. The levels of p62 and LC3B-II, autophagy markers, were also upregulated in the hUCBMNC-treated group.

Conclusion: hUCBMNCs as a kind of cell therapeutic strategy could attenuate acute liver injury in mice, which is executed by enhancing autophagy and regeneration in the liver via inhibiting inflammatory responses and upregulating peripheral IL-22.

The Bioactivities of Phycocyanobilin from Spirulina

Phycocyanobilin (PCB) is a linear open-chain tetrapyrrole chromophore that captures and senses light and a variety of biological activities, such as anti-oxidation, anti-cancer, and anti-inflammatory. In this paper, the biological activities of PCB are reviewed, and the related mechanism of PCB and its latest application in disease treatment are introduced. PCB can resist oxidation by scavenging free radicals, inhibiting the activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, and delaying the activity of antioxidant enzymes. In addition, PCB can also be used as an excellent anti-inflammatory agent to reduce the proinflammatory factors IL-6 and IFN-γ and to up-regulate the production of anti-inflammatory cytokine IL-10 by inhibiting the inflammatory signal pathways NF-κB and mitogen-activated protein kinase (MAPK). Due to the above biological activities of phycocyanobilin PCB, it is expected to become a new effective drug for treating various diseases, such as COVID-19 complications, atherosclerosis, multiple sclerosis (MS), and ischaemic stroke (IS).

Protective effect of C-phycocyanin and apo-phycocyanin subunit on programmed necrosis of GC-1 spg cells induced by H2 O2

C-phycocyanin (C-PC) is an effective antioxidant and has an important value in medical research. Oxidative stress is considered to be one of the main underlying mechanisms of cell death, and reducing oxidative stress is one of the strategies to enhance germ cell viability. Herein, we investigated the protective effect and the mechanism of C-PC and apo-phycocyanin subunit on oxidative stress damage induced by H₂ O₂ in GC-1 spg cells. C-PC genes were cloned into the pGEX-4T-1 vectorand transformed into Escherichia coli BL21 to achieve the efficient expression of C-PC subunit. GC-1 spg cells were treated with 600 μM H₂ O₂ for 24 h to establish the oxidative stress damage model. Cell viability was detected by CCK-8. The degree of oxidative stress was detected by testing Superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities and glutathione (GSH) and Malondialdehyde (MDA) levels. Reactive oxygen species (ROS) was evaluated utilizingby 2', 7'-dichlorofluorescent-diacetate (DCFH-DA). Mitochondrial membrane potential was determined by JC-1. Cell necrosis rate was detected by Annexin V-FITC/PI. Expression of protein was detected by western blot. We found that C-PC and GST-CPC β significantly inhibited H₂ O₂ -induced oxidative damage of GC-1 spg cells, improved the ability of antioxidation, reduced ROS overproduction, and mitochondrial membrane potential loss, and inhibited the RIP-1/RIP-3/ p-MLKL signaling pathway to reduce the necrosis rate. The results demonstrated that C-PC played a protective role against H₂ O₂ -induced cell damage, especially its β subunit. This study provides a theoretical basis for C-PC as a potential protective agent of reproductive system.

Serum superoxide dismutase level is a potential biomarker of disease prognosis in patients with HEV-induced liver failure

Background

Viral hepatitis E clinically ranges from self-limiting hepatitis to lethal liver failure. Oxidative stress has been shown to mediate hepatic inflammation during HBV-induced liver failure. We investigated whether a biomarker of oxidative stress may be helpful in assessing severity and disease outcomes of patients with HEV-induced liver failure.

Methods

Clinical data were obtained from patients with HEV-induced acute viral hepatitis (AVH, n = 30), acute liver failure (ALF, n = 17), and acute-on-chronic liver failure (ACLF, n = 36), as well as from healthy controls (HC, n = 30). The SOD and HMGB1 levels were measured in serum by ELISA. HL-7702 cells were cultured and stimulated by serum from HEV-infected patients or by HMGB1; oxidative status was investigated by CellROX and apoptosis was investigated by flow cytometry.

Results

Patients with HEV-induced liver failure (including ALF and ACLF) showed increased SOD levels compared with HEV-AVH patients and healthy controls. SOD levels > 400 U/mL were associated with a significantly higher risk of mortality in HEV-ALF and HEV-ACLF patients. Serum from HEV-infected patients led to ROS accumulation, HMGB1 secretion, and apoptosis in HL-7702 cells. Antioxidant treatment successfully inhibited HEV-induced HMGB1 secretion, and HMGB1 promoted apoptosis in HL-7702 cells.

Conclusion

HEV increased oxidative stress in the pathogenesis of HEV-induced hepatic diseases. Early testing of serum SOD may serve as a predictor of both HEV-ALF and HEV-ACLF outcomes. Moreover, development of strategies for modulating oxidative stress might be a potential target for treating HEV-induced liver failure patients.

Advantages of adipose tissue stem cells over CD34+ mobilization to decrease hepatic fibrosis in Wistar rats

INTRODUCTION AND OBJECTIVES

Chronic liver inflammation may lead to hepatic cirrhosis, limiting its regenerative capacity. The clinical standard of care is transplantation, although stem cell therapy may be an alternative option. The study aim was to induce endogenous hematopoietic stem cells (HSCs) with granulocyte colony stimulating factor (G-CSF) and/or intravenous administration of adipose tissue-derived mesenchymal stem cells (MSCs) to decrease hepatic fibrosis in an experimental model.

MATERIAL AND METHODS

A liver fibrosis model was developed with female Wistar rats via multiple intraperitoneal doses of carbon tetrachloride. Three rats were selected to confirm cirrhosis, and the rest were set into experimental groups to evaluate single and combined therapies of G-CSF-stimulated HSC mobilization and intravenous MSC administration.

RESULTS

Treatment with MSCs and G-CSF significantly improved alanine amino transferase levels, while treatment with G-CSF, MSCs, and G-CSF+MSCs decreased aspartate amino transferase levels. Hepatocyte growth factor (HGF) and interleukin 10 levels increased with MSC treatment. Transforming growth factor β levels were lower with MSC treatment. Interleukin 1β and tumor necrosis factor alpha levels decreased in all treated groups. Histopathology showed that MSCs and G-CSF reduced liver fibrosis from F4 to F2.

CONCLUSIONS

MSC treatment improves liver function, decreases hepatic fibrosis, and plays an anti-inflammatory role; it promotes HGF levels and increased proliferating cell nuclear antigen when followed by MSC treatment mobilization using G-CSF. When these therapies were combined, however, fibrosis improvement was less evident.

Hepatoprotective Effects of Standardized Extracts from an Ancient Italian Apple Variety (Mela Rosa dei Monti Sibillini) against Carbon Tetrachloride (CCl4)-Induced Hepatotoxicity in Rats

The aim of this research was to examine the effect of the hydroalcoholic extracts from the peel (APE) and pulp (APP) of a traditional apple cultivar from central Italy (Mela Rosa dei Monti Sibillini) on CCl4-induced hepatotoxicity in rats. Phytoconstituents were determined by liquid chromatography-mass spectrometry (LC-MS) analysis showing an abundance of proanthocyanidins and flavonol derivatives together with the presence of annurcoic acid in APE. Wistar rats received APE/APP (30 mg/kg oral administration) for three days before CCl4 injection (2 mL/kg intraperitoneal once on the third day). Treatment with both APE and APP prior to CCl4 injection significantly decreased the serum levels of aspartate aminotransferase (AST), alkaline phosphatase (ALP) and alanine aminotransferase (ALT) compared to the CCl4 group. Besides, pretreatment with APE reversed the CCl4 effects on superoxide dismutase (SOD), myeloperoxidase (MPO), tumor necrosis factor-α (TNF-α) and interleukin-1beta (IL-1β) levels in liver tissue in rats and reduced tissue damage as shown in hematoxylin and eosin staining. These results showed that this ancient Italian apple is worthy of use in nutraceuticals and dietary supplements to prevent and/or protect against liver disorders.

Hepatoprotective activity of raspberry ketone is mediated via inhibition of the NF-κB/TNF-α/caspase axis and mitochondrial apoptosis in chemically induced acute liver injury

Raspberry Ketone (RK) is a natural phenolic compound which is marketed nowadays as a popular weight-reducing remedy, with reported antioxidant and anti-inflammatory activities. However, its biological activity is not fully elucidated. Hepatotoxicity is the leading cause of acute liver failure in Europe and North America, and its management is still challenging. Therefore, this study aimed to assess the therapeutic detoxification activity of RK against liver injury in vivo and to explore the underlying mechanisms using carbon tetrachloride (CCl₄)-induced hepatotoxicity as a model. First, a dose-response study using 4 different doses, 25, 50, 100, and 200 mg kg^-1 day^-1, of RK was conducted. RK was administered for 5 days as a pretreatment, followed by a single dose of CCl₄ (1 ml kg^-1, 1 : 1 v/v CCl₄ : olive oil)_. The RK dose of 200 mg kg^-1 showed the greatest protective effect and was selected for further investigations. CCl₄ hepatotoxicity was confirmed by elevation of liver enzymes, and histopathological examination. CCl₄-induced oxidative stress was evident from increased lipid peroxidation measured as thiobarbituric acid reactive substances (TBARS) along with depleted superoxide dismutase (SOD), reduced glutathione (GSH), and total antioxidant capacity (TAC). Increased oxidative stress was associated with increased cytochrome c expression with subsequent activation of caspase-9 and caspase-3, in addition to DNA fragmentation reflecting apoptosis. CCl₄ also induced the expression of inflammatory cytokines (NF-κB and TNF-α). Interestingly, RK hepatoprotective activity was evident from the reduction of liver enzymes, and maintenance of hepatocyte integrity and microstructures as evaluated by histopathological examination using H and E, and transmission electron microscopy. The antioxidant activity of RK was demonstrated by the increase of TAC, SOD, and GSH, with a concomitant decrease of the TBARS level. Moreover, RK pretreatment inhibited CCl₄-induced upregulation of inflammatory mediators. RK antiapoptotic activity was indicated by the reduction of the expression of cytoplasmic cytochrome-C, a decrease of caspases, and inhibition of DNA fragmentation. In conclusion, this study demonstrates that RK is a promising hepatoprotective agent. The underlying mechanisms include antioxidant, anti-inflammatory, and anti-apoptotic activities. This is the first study reporting RK hepatoprotective activity in acute hepatic injury and approves its antiapoptotic effect in the liver.

Dynamics of elastin in liver fibrosis: Accumulates late during progression and degrades slowly in regression

Elastin is an amorphous protein highly resistant to elastase degradation and is believed to be the most stable component among the extracellular matrix (ECM) members. Thus the excessive deposition of elastin in advanced liver fibrosis may contribute to the declining reversibility of the disease. Our previous study has found that elastin crosslinking inhibition can effectively arrest liver fibrosis progression. To further understand the roles of elastin involved in liver fibrosis, we systematically investigated the expression, accumulation, and degradation based on dynamic and bidirectional CCl₄ -induced liver fibrosis mouse models and visualized the ultrastructure of elastin globules in cultured LX-2 cells. We found that the expression pattern of tropoelastin (soluble elastin) and collagen I was not completely comparable at both the transcriptional and posttranscriptional levels during liver fibrosis progression and regression. Elastin mainly accumulated onto the internodular fibrous septa and enlarged portal areas and intertwined with collagen I at the late stage of liver fibrosis. Three-dimensional analysis of elastin and collagen I by confocal immunofluorescence coupled with biochemical analyses revealed that with respect to collagen, elastin deposition was characterized by late aggregation in progression and slow turnover in regression. In addition, we visualized the dynamic ultrastructure of ECM fibers during liver fibrogenesis and fibrolysis and the ultrastructure of elastin globules self-aggregated by tropoelastin crosslinking. Our current study established new general hallmarks of elastin levels and forms in progressive and regressive liver fibrosis and provided a foundation for further experimental investigation of the growing role of elastin in liver fibrosis regression.

Diallyl sulfide treatment protects against acetaminophen-/carbon tetrachloride-induced acute liver injury by inhibiting oxidative stress, inflammation and apoptosis in mice

The purpose of the present study was to investigate the effects and underlying mechanisms of diallyl sulfide (DAS), an organosulfur compound extracted from garlic, on drug-induced or chemical-induced liver injury caused by acetaminophen (APAP) or carbon tetrachloride (CCl4) in mice. DAS (100, 200, or 400 μmol kg-1) was orally administered 1 hour before APAP or CCl4 intraperitoneal injection, and the serum and liver tissue were collected 24 hours after APAP or CCl4 exposure. The serum aminotransferase activities and liver histopathological examination showed that DAS exhibited obvious hepatoprotective effects against acute liver injury induced by APAP or CCl4. In addition, exposure to APAP or CCl4 resulted in an increased content of malonaldehyde as well as a decreased ratio of reduced to oxidized glutathione, and a decreased level of superoxide dismutase and catalase activity in the liver (p < 0.05); however, pretreatment with DAS restored the perturbations of the antioxidant system in the liver. Beyond that, DAS pretreatment reduced the APAP-/CCl4-induced increase in phosphorylation of inhibitor of kappa B alpha (IκBα) and p65 subunit of nuclear factor kappa B (NF-κB) expression in the cytoplasm and nucleus in the liver. DAS pretreatment also decreased the excessive level of TNF-α caused by APAP or CCl4 in serum (p < 0.05). Moreover, DAS pretreatment regulated the expression of cleaved caspase 3, Bax and Bcl-2 in the liver and suppressed APAP-/CCl4-induced hepatocyte apoptosis. In conclusion, DAS exhibits hepatoprotective effects against drug-induced and chemical-induced liver injuries induced by APAP or CCl4 in mice, probably due to its ability to reduce hepatic oxidative stress and inhibit inflammatory injury and hepatocyte apoptosis.

Assessment of the possible roles of SB-269970 versus ketanserin on carbon tetrachloride-induced liver fibrosis in rats: Oxidative stress/TGF-β1-induced HSCs activation pathway

BACKGROUND

In liver fibrosis, a major morbid and mortal disease, oxidative stress motivation of hepatic stellate cells (HSCs)-into myofibroblasts terminated in collagen deposition remain the key pathophysiological deal. Serotonin (5-HT) through its HSCs-expressed receptors, especially 5-HT2A and 7, shows crucial events in fibrogenesis of chronic liver diseases. Molecular hepatic oxidative stress-fibrotic roles of 5-HT2A and 7 receptors antagonists (ketanserin and SB-269970 respectively) are still a challenging issue.

METHODS

Seven groups of adult male Wistar rats (n=10) were used. A carbon tetrachloride (CCl₄) solution was injected intraperitoneally twice weekly for 6 weeks. On the 7th week, rats developed liver fibrosis were treated either by ketanserin (1mg/kg/day, ip) or SB-269970 (2mg/kg/day, ip) for 14days. Survival rates, and serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in addition to hepatic malondialdehyde (MDA) and reduced glutathione (GSH) levels, superoxide dismutase (SOD) and catalase (CAT) activities, and transforming growth factor-beta1 (TGF-β₁) and procollagen type I N-terminal propeptide (PINP) levels, beside the hepatic histopathological fibrotic changes, were evaluated.

RESULTS

In CCl₄-challenged rats, each therapeutic approach showed significant reductions in elevated serum ALT, and AST levels, hepatic MDA, TGF-β₁, and PINP levels, and histopathological hepatic fibrotic scores as well as significant elevations in survival rates, reduced hepatic GSH levels, and SOD, and CAT activities. Remarkably, significant ameliorative measurements were observed in SB-269970 treated group.

CONCLUSION

Blockade of 5-HT2A and 7 receptors each alone could be a future reliable therapeutic approach in liver fibrosis through a reduction in oxidative stress/TGF-β₁-induced HSCs activation pathway.

Clinical Safety of a High Dose of Phycocyanin-Enriched Aqueous Extract from Arthrospira (Spirulina) platensis: Results from a Randomized, Double-Blind, Placebo-Controlled Study with a Focus on Anticoagulant Activity and Platelet Activation

The goal for this study was to evaluate safety regarding anticoagulant activity and platelet activation during daily consumption of an aqueous cyanophyta extract (ACE), containing a high dose of phycocyanin. Using a randomized, double-blind, placebo-controlled study design, 24 men and women were enrolled after informed consent, and consumed either ACE (2.3 g/day) or placebo daily for 2 weeks. The ACE dose was equivalent to ∼1 g phycocyanin per day, chosen based on the highest dose Generally Recognized as Safe (GRAS) by the U.S. Food and Drug Administration. Consuming ACE did not alter markers for platelet activation (P-selectin expression) or serum P-selectin levels. No changes were seen for activated partial thromboplastin time, thrombin clotting time, or fibrinogen activity. Serum levels of aspartate transaminase (AST) showed a significant reduction after 2 weeks of ACE consumption (P < .001), in contrast to placebo where no changes were seen; the difference in AST levels between the two groups was significant at 2 weeks (P < .02). Reduced levels of alanine transaminase (ALT) were also seen in the group consuming ACE (P < .08). Previous studies showed reduction of chronic pain when consuming 1 g ACE per day. The higher dose of 2.3 g/day in this study was associated with significant reduction of chronic pain at rest and when physically active (P < .05). Consumption of ACE showed safety regarding markers pertaining to anticoagulant activity and platelet activation status, in conjunction with rapid and robust relief of chronic pain. Reduction in AST and ALT suggested improvement in liver function and metabolism.