Colonic and Hepatic Modulation by Lipoic Acid and/or N-Acetylcysteine Supplementation in Mild Ulcerative Colitis Induced by Dextran Sodium Sulfate in Rats

Extraintestinal Manifestations in Induced Colitis: Controversial Effects of N-Acetylcysteine on Colon, Liver, and Kidney

Ulcerative colitis (UC) is a chronic and recurrent inflammatory bowel disease (IBD) characterized by continuous inflammation in the colonic mucosa. Extraintestinal manifestations (EIM) occur due to the disruption of the intestinal barrier and increased permeability caused by redox imbalance, dysbiosis, and inflammation originating from the intestine and contribute to morbidity and mortality. The aim of this study is to investigate the effects of oral N-acetylcysteine (NAC) on colonic, hepatic, and renal tissues in mice with colitis induced by dextran sulfate sodium (DSS). Male Swiss mice received NAC (150 mg/kg/day) in the drinking water for 30 days before and during (DSS 5% v/v; for 7 days) colitis induction. On the 38th day, colon, liver, and kidney were collected and adequately prepared for the analysis of oxidative stress (superoxide dismutase (SOD), catalase (CAT), glutathione reduced (GSH), glutathione oxidized (GSSG), malondialdehyde (MDA), and hydrogen peroxide (H2O2)) and inflammatory biomarkers (myeloperoxidase (MPO) -, tumor necrosis factor alpha - (TNF-α, and interleukin-10 (IL-10)). In colon, NAC protected the histological architecture. However, NAC did not level up SOD, in contrast, it increased MDA and pro-inflammatory effect (increased of TNF-α and decreased of IL-10). In liver, colitis caused both oxidative (MDA, SOD, and GSH) and inflammatory damage (IL-10). NAC was able only to increase GSH and GSH/GSSG ratio. Kidney was not affected by colitis; however, NAC despite increasing CAT, GSH, and GSH/GSSG ratio promoted lipid peroxidation (increased MDA) and pro-inflammatory action (decreased IL-10). Despite some beneficial antioxidant effects of NAC, the negative outcomes concerning irreversible oxidative and inflammatory damage in the colon, liver, and kidney confirm the nonsafety of the prophylactic use of this antioxidant in models of induced colitis, suggesting that additional studies are needed, and its use in humans not yet recommended for the therapeutic routine of this disease.

Anthocyanin extract from black rice attenuates chronic inflammation in DSS-induced colitis mouse model by modulating the gut microbiota

There is substantial evidence for the probiotic activity of anthocyanins, but the relationship between anthocyanins involved in the regulation of microbiota and intestinal inflammation has not been fully elucidated. The aim of this study was to investigate the regulatory effects of black rice anthocyanin extract (BRAE) on intestinal microbiota imbalance in mice with dextran sulfate sodium (DSS)-induced chronic colitis. DSS was added into drinking water to induce a mouse model of chronic experimental colitis, and BRAE was given by gavage (200 mg/kg/day) for 4 weeks. Body weight, fecal viscosity, and hematochezia were monitored during administration. After mice were sacrificed, the serum concentrations of TNF-α and IL-6 were detected by enzyme-linked immunosorbent assay, and the composition of intestinal flora was analyzed by 16S rDNA sequencing. The results showed that BRAE significantly suppressed DSS-induced colonic inflammatory phenotypes and maintained colon length in mice. In addition, BRAE reduced intestinal permeability and improved intestinal barrier dysfunction in mice with colitis. Gut microbiota analysis showed that BRAE significantly improved the imbalance of intestinal microecological diversity caused by DSS, inhibited the increase in the relative abundance of inflammatory bacteria, and promoted the abundance of anti-inflammatory probiotics including Akkermansia spp.

Dental pulp stem cells overexpressing hepatocyte growth factor facilitate the repair of DSS-induced ulcerative colitis

Background

Ulcerative colitis (UC) is a chronic and recurrent disease without satisfactory treatment strategies. Dental pulp stem cell (DPSC) transplantation has been proposed as a potential therapy for UC. This study aimed to investigate the therapeutic effects of the rat hepatocyte growth factor (HGF) gene transduced into DPSCs for UC.

Methods

The therapeutic effects of HGF-DPSCs transplanted intravenously into a rat model of UC induced by 5% dextran sulphate sodium (DSS) were compared with the other treatment groups (LV-HGF group, DPSCs group and GFP-DPSCs group). Immunofluorescence and immunohistochemistry were used to observe the localization and proliferation of HGF-DPSCs at the site of colon injury. The expression levels of inflammatory factors were detected by real-time quantitative PCR (RT-PCR) and western blotting. The oxidative stress markers were detected by ELISA. DAI scores and body weight changes were used to macroscopically evaluate the treatment of rats in each group.

Results

Immunofluorescence and immunohistochemistry assays showed that HGF-DPSCs homed to colon injury sites and colocalized with intestinal stem cell (ISC) markers (Bmi1, Musashi1 and Sox9) and significantly promoted protein expression (Bmi1, Musashi1, Sox9 and PCNA). Anti-inflammatory cytokine (TGF-β and IL-10) expression was the highest in the HGF-DPSCs group compared with the other treatment groups, while the expression of pro-inflammatory cytokines (TNF-α and INF-γ) was the lowest. Additionally, the oxidative stress response results showed that malondialdehyde (MDA) and myeloperoxidase (MPO) expression decreased while superoxide dismutase (SOD) expression increased, especially in the HGF-DPSCs group. The DAI scores showed a downward trend with time in the five treatment groups, whereas body weight increased, and the changes were most prominent in the HGF-DPSCs group.

Conclusions

The study indicated that HGF-DPSCs can alleviate injuries to the intestinal mucosa by transdifferentiating into ISC-like cells, promoting ISC-like cell proliferation, suppressing inflammatory responses and reducing oxidative stress damage, which provides new ideas for the clinical treatment of UC.

Preventing Colitis-Associated Colon Cancer With Antioxidants: A Systematic Review

Inflammatory bowel disease (IBD) patients have an increased risk of developing colitis-associated colon cancer (CAC); however, the basis for inflammation-induced genetic damage requisite for neoplasia is unclear. Several studies have shown that IBD patients have signs of increased oxidative damage, which could be a result of genetic and environmental factors such as an excess in oxidant molecules released during chronic inflammation, mitochondrial dysfunction, a failure in antioxidant capacity, or oxidant promoting diets. It has been suggested that chronic oxidative environment in the intestine leads to the DNA lesions that precipitate colon carcinogenesis in IBD patients. Indeed, several preclinical and clinical studies show that different endogenous and exogenous antioxidant molecules are effective at reducing oxidation in the intestine. However, most clinical studies have focused on the short-term effects of antioxidants in IBD patients but not in CAC. This review article examines the role of oxidative DNA damage as a possible precipitating event in CAC in the context of chronic intestinal inflammation and the potential role of exogenous antioxidants to prevent these cancers.

The Alpha-Lipoic Acid Improves Survival and Prevents Irinotecan-Induced Inflammation and Intestinal Dysmotility in Mice

Irinotecan, an anticancer drug, induces diarrhea and intestinal inflammation, resulting in an increase in the cost of care and in treatment delays. In this study, we investigated whether alpha-lipoic acid (α-LA) could improve irinotecan-mediated intestinal inflammation, diarrhea and dysmotility. Intestinal mucositis was induced by irinotecan injection (75 mg/kg, i.p., for 4 days) in Swiss mice. α-LA (50, 100 or 200 mg/kg, gavage) was administered daily 1 h before the injection of irinotecan. Duodenum tissues were obtained for inflammation and proliferation analysis. The outcomes: diarrhea, intestinal dysmotility, weight body loss and survival were evaluated. Compared with the control condition, irinotecan diminished (p < 0.05) intestinal villus height, caused a loss of crypt integrity and intense inflammatory cell infiltration, increased myeloperoxidase (MPO), IL-6 and IL-1β levels and decreased reduced glutathione (GSH) levels in duodenum segments and increased gastric retention and decreased liquid retention in the medial intestinal segment, resulting in increased intestinal transit, severe diarrhea and reduced survival (approximately 72%). Furthermore, α-LA (200 mg/kg) pretreatment ameliorated (p < 0.05) these irinotecan-induced effects. Our findings show that α-LA reduced irinotecan-induced inflammation, intestinal dysmotility and diarrhea, resulting in improved survival. α-LA may be a useful therapeutic agent for the treatment of gut dysmotility in patients with intestinal mucositis associated with irinotecan treatment.

Oxidative stress resulting from the removal of endogenous catalase induces obesity by promoting hyperplasia and hypertrophy of white adipocytes

Obesity is regarded as an abnormal expansion and excessive accumulation of fat mass in white adipose tissue. The involvement of oxidative stress in the development of obesity is still unclear. Although mainly present in peroxisomes, catalase scavenges intracellular H₂O₂ at toxic levels. Therefore, we used catalase-knockout (CKO) mice to elucidate the involvement of excessive H₂O₂ in the development of obesity. CKO mice with C57BL/6J background gained more weight with higher body fat mass with age than age-matched wild-type (WT) mice fed with either chow or high-fat diets. This phenomenon was attenuated by concomitant treatment with the antioxidants, melatonin or N-acetyl cysteine. Moreover, CKO mouse embryonic fibroblasts (MEFs) appeared to differentiate to adipocytes more easily than WT MEFs, showing increased H₂O₂ concentrations. Using 3T3-L1-derived adipocytes transfected with catalase-small interfering RNA, we confirmed that a more prominent lipogenesis occurred in catalase-deficient cells than in WT cells. Catalase-deficient adipocytes presented increased nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) expression but decreased adenosine monophosphate-activated protein kinase (AMPK) expression. Treatment with a NOX4 inhibitor or AMPK activator rescued the propensity for obesity of CKO mice. These findings suggest that excessive H₂O₂ and related oxidative stress increase body fat mass via both adipogenesis and lipogenesis. Manipulating NOX4 and AMPK in white adipocytes may be a therapeutic tool against obesity augmented by oxidative stress.

Aging-Related Disorders and Mitochondrial Dysfunction: A Critical Review for Prospect Mitoprotective Strategies Based on Mitochondrial Nutrient Mixtures

A number of aging-related disorders (ARD) have been related to oxidative stress (OS) and mitochondrial dysfunction (MDF) in a well-established body of literature. Most studies focused on cardiovascular disorders (CVD), type 2 diabetes (T2D), and neurodegenerative disorders. Counteracting OS and MDF has been envisaged to improve the clinical management of ARD, and major roles have been assigned to three mitochondrial cofactors, also termed mitochondrial nutrients (MNs), i.e., α-lipoic acid (ALA), Coenzyme Q10 (CoQ10), and carnitine (CARN). These cofactors exert essential–and distinct—roles in mitochondrial machineries, along with strong antioxidant properties. Clinical trials have mostly relied on the use of only one MN to ARD-affected patients as, e.g., in the case of CoQ10 in CVD, or of ALA in T2D, possibly with the addition of other antioxidants. Only a few clinical and pre-clinical studies reported on the administration of two MNs, with beneficial outcomes, while no available studies reported on the combined administration of three MNs. Based on the literature also from pre-clinical studies, the present review is to recommend the design of clinical trials based on combinations of the three MNs.

The Close Interplay of Nitro-Oxidative Stress, Advanced Glycation end Products and Inflammation in Inflammatory Bowel Diseases

BACKGROUND

Inflammatory Bowel Disease (IBD) exhibits no defined aetiology. However, factors such as genetic and nitro-oxidative stress are associated with chronic inflammation and IBD progression to Colorectal Cancer (CRC). The present review discusses the association of nitro-oxidative stress, inflammation and Advanced Glycation End products (AGE) and their corresponding receptor (RAGE) in IBD and examines the connection between these factors and nuclear factors, such as Nuclear Factor Kappa B (NF-κB), factorerythroid 2-related factor-2 (Nrf2), and p53 Mutant (p53M).

METHODS

We searched the PubMed, ScienceDirect and Web of Science databases using a combination of the following terms: IBD, CRC, oxidative stress, inflammation, NF-κB, Nrf2, p53M, AGE and RAGE.

RESULTS

Oxidative stress and inflammation activated two cellular pathways, the nuclear expression of pro-inflammatory, pro-oxidant and pro-oncogenic genes based on NF-κB and p53M, which is associated with NF-κB activation, Deoxyribonucleic acid (DNA) damage and the expression of pro-oncogenic genes. Nrf2 stimulates the nuclear expression of enzymatic and non-enzymatic antioxidant systems and anti-inflammatory genes, and is inhibited by chronic oxidative stress, NF-κB and p53M. AGE/RAGE are involved in inflammation progression because RAGE polymorphisms and increased RAGE levels are found in IBD patients. Alterations of these pathways in combination with oxidative damage are responsible for IBD symptoms and the progression to CRC.

CONCLUSION

IBD is an inflammatory and nitro-oxidative stress-based bowel disease. Achieving a molecular understanding of the biochemical events and their complicated interactions will impact basic and applied research, animal models, and clinical trials.

Ablation of catalase promotes non-alcoholic fatty liver via oxidative stress and mitochondrial dysfunction in diet-induced obese mice

Hydrogen peroxide (H₂O₂) produced endogenously can cause mitochondrial dysfunction and metabolic complications in various cell types by inducing oxidative stress. In the liver, oxidative and endoplasmic reticulum (ER) stress affects the development of non-alcoholic fatty liver disease (NAFLD). Although a link between both stresses and fatty liver diseases has been suggested, few studies have investigated the involvement of catalase in fatty liver pathogenesis. We examined whether catalase is associated with NAFLD, using catalase knockout (CKO) mice and the catalase-deficient human hepatoma cell line HepG2. Hepatic morphology analysis revealed that the fat accumulation was more prominent in high-fat diet (HFD) CKO mice compared to that in age-matched wild-type (WT) mice, and lipid peroxidation and H₂O₂ release were significantly elevated in CKO mice. Transmission electron micrographs indicated that the liver mitochondria from CKO mice tended to be more severely damaged than those in WT mice. Likewise, mitochondrial DNA copy number and cellular ATP concentrations were significantly lower in CKO mice. In fatty acid-treated HepG2 cells, knockdown of catalase accelerated cellular lipid accumulation and depressed mitochondrial biogenesis, which was recovered by co-treatment with N-acetyl cysteine or melatonin. This effect of antioxidant was also true in HFD-fed CKO mice, suppressing fatty liver development and improving hepatic mitochondrial function. Expression of ER stress marker proteins and hepatic fat deposition also increased in normal-diet, aged CKO mice compared to WT mice. These findings suggest that H₂O₂ production may be an important event triggering NAFLD and that catalase may be an attractive therapeutic target for preventing NAFLD.

Effects of alpha lipoic acid and its derivative "andrographolid-lipoic acid-1" on ulcerative colitis: A systematic review with meta-analysis of animal studies

We aimed to review and meta-analyze the inflammatory and oxidative factors following alpha lipoic acid (ALA) and its derivative "andrographolid-lipoic acid-1" (AL-1) in ulcerative colitis (UC). ALA plays an important role in scavenging intracellular radicals and inflammatory elements. AL-1 is found in herbal medicines with potent anti-inflammatory properties. Data were collected from the Google Scholar, PubMed, Scopus, Evidence-based medicine/clinical trials, and Cochrane library database until 2017, which finally resulted in 22 animal studies (70 rats and 162 mice). The beneficial effects of ALA or AL-1 on the most important parameters of UC were reviewed; also, studies were considered separately in mice and rats. Administration of ALA and AL-1 significantly reduced the tumor necrosis factor-α level compared with the controls, while data were not noteworthy in the meta-analysis (mean differences = -18.57 [95% CI = -42.65 to 5.51], P = 0.13). In spite of insignificant decrease in meta-analysis outcomes (differences = 6.92 [95% CI = -39.33 to 53.16], P = 0.77), a significant reduction in myeloperoxidase activity was shown following ALA or AL-1 treatment compared with the controls. Despite significant differences in each study, we had to exclude some studies to homogenize data for meta-analyzing as they showed insignificant results. Interleukin 6, cyclooxygenase-2, glutathione, malondialdehyde, superoxide dismutase, histopathological score, macroscopic and microscopic scores, disease activity index, body weight change, and colon length were also reviewed. Most studies have emphasized on significant positive effects of ALA and AL-1. Comprehensive clinical trials are obligatory to determine the precious position of ALA or AL-1 in the management of UC.

Synthesis of magnolol and honokiol derivatives and their effect against hepatocarcinoma cells

The hepatocellular carcinoma is one of the most common malignant tumour with high level of mortality rate due to its rapid progression and high resistance to conventional chemotherapies. Thus, the search for novel therapeutic leads is of global interest. Herein, a small set of derivatives of magnolol 1 and honokiol 2, the main components of Magnolia grandiflora and Magnolia obovata, were evaluated in in vitro assay using tumoral hepatocytes. The pro-drug approach was applied as versatile strategy to the improve bioactivity of the compounds by careful transformation of the hydroxyl groups of magnolol 1 and honokiol 2 in suitable ester derivatives. Compounds 10 and 11 resulted to be more potent than the parental honokiol 2 at concentration down to 1 μM with complete viability of treated fibroblast cells up to concentrations of 80 μM. The combination of a butyrate ester and a bare phenol-OH group in the honokiol structure seemed to play a significant role in the antiproliferative activity identifying an interesting pharmacological clue against hepatocellular carcinoma.

New insights on the modulatory roles of metformin or alpha-lipoic acid versus their combination in dextran sulfate sodium-induced chronic colitis in rats

BACKGROUND

Dextran sulfate sodium (DSS)-induced colitis is the most widely used model that resembles ulcerative colitis (UC) in human with challenging chronic mechanistic oxidative stress-inflammatory/immunological cascades. In models of acute colitis, reduction of oxidative stress and inflammatory burdens beside manipulation of many transcriptional factors were achieved by metformin or alpha-lipoic acid (α-LA). Currently, in vivo DSS-induced chronic colitis was conducted and the possible therapeutic roles of metformin and/or α-LA were explored.

METHODS

Chronic UC was induced by adding 5% DSS orally in drinking water for 7days followed by 3% DSS in drinking water for 14days in adult male albino Wistar rats. Intraperitoneal administration of α-LA (25mg/kg, twice/day) and/or metformin (100mg/kg/day) were set at day 7 of DSS administration and continued for 14days. Body weights, survival rates, disease activity index (DAI), colonic oxidative stress markers, tumor necrosis factor (TNF)-α levels, colonic nuclear factor-kappa-B (NF-κB) immunohistochemical expression, and the colonic histopathological changes were observed.

RESULTS

Metformin or/and α-LA attenuated the severity of the DSS-induced colitis through improving the reductions in body weights, the DAI, the colonic oxidative stress markers, TNF-α, and NF-κB levels, and the morphological mucosal damage scores. Significant synergetic therapeutic effects were observed with combined therapeutic regimens.

CONCLUSION

Therapeutically, metformin and α-LA could be administered in chronic colitis. The combination of currently used pharmaceutics with natural and synthetic potent antioxidant compounds will become a therapeutic strategy of choice for UC to improve the quality of life if sufficient clinical trials are available.