Protective effect of sucrose esters from cape gooseberry (Physalis peruviana L.) in TNBS-induced colitis.

Phytotherapy is an attractive strategy to treat inflammatory bowel disease (IBD) that could be especially useful in developing countries. We previously demonstrated the intestinal anti-inflammatory effect of the total ethereal extract from the Physalis peruviana (Cape gooseberry) calyces in TNBS-induced colitis. This work investigates the therapeutic potential of Peruviose A and B, two sucrose esters that constitute the major metabolites of its calyces. The effect of the Peruvioses A and B mixture on TNBS-induced colitis was studied after 3 (preventive) and 15-days (therapy set-up) of colitis induction in rats. Colonic inflammation was assessed by measuring macroscopic/histologic damage, MPO activity, and biochemical changes. Additionally, LPS-stimulated RAW 264.7 macrophages were treated with test compounds to determine the effect on cytokine imbalance in these cells. Peruvioses mixture ameliorated TNBS-induced colitis in acute (preventive) or established (therapeutic) settings. Although 3-day treatment with compounds did not produce a potent effect, it was sufficient to significantly reduce the extent/severity of tissue damage and the microscopic disturbances. Beneficial effects in the therapy set-up were substantially higher and involved the inhibition of pro-inflammatory enzymes (iNOS, COX-2), cytokines (TNF-α, IL-1ß, and IL-6), as well as epithelial regeneration with restoration of goblet cells numbers and expression of MUC-2 and TFF-3. Consistently, LPS-induced RAW 264.7 cells produced less NO, PGE2, TNF-α, IL-6, and MCP-1. These effects might be related to the inhibition of the NF-κB signaling pathway. Our results suggest that sucrose esters from P. peruviana calyces, non-edible waste from fruit production, might be useful as an alternative IBD treatment.

Preparation, Characterization and Evaluation of the Anti-Inflammatory Activity of Epichlorohydrin-ß-Cyclodextrin/Curcumin Binary Systems Embedded in a Pluronic®/Hyaluronate Hydrogel.

Curcumin (Cur) is an anti-inflammatory polyphenol that can be complexed with polymeric cyclodextrin (CD) to improve solubility and bioavailability. The aim of the present work was to prepare a CurCD hydrogel to treat inflammatory skin conditions. Epichlorohydrin-ß-CD (EpißCD) was used as polymeric CD. To characterize the binary system, solid-state and in-solution studies were performed. Afterwards, an experimental design was performed to optimize the hydrogel system. Finally, the CurEpißCD hydrogel system was tested for anti-inflammatory activity using a HaCat psoriasis cell model. Co-grinded Cur/EpißCD binary system showed a strong interaction and Curcumin solubility was much improved. Its combination with Pluronic® F-127/hyaluronate hydrogel demonstrated an improvement in release rate and Curcumin permeation. After testing its anti-inflammatory activity, the system showed a significant reduction in IL-6 levels. Hydrogel-containing CurEpißCD complex is a great alternative to treat topical inflammatory diseases.

Anti-Inflammatory and Anticancer Effects of Microalgal Carotenoids.

Acute inflammation is a key component of the immune system's response to pathogens, toxic agents, or tissue injury, involving the stimulation of defense mechanisms aimed to removing pathogenic factors and restoring tissue homeostasis. However, uncontrolled acute inflammatory response may lead to chronic inflammation, which is involved in the development of many diseases, including cancer. Nowadays, the need to find new potential therapeutic compounds has raised the worldwide scientific interest to study the marine environment. Specifically, microalgae are considered rich sources of bioactive molecules, such as carotenoids, which are natural isoprenoid pigments with important beneficial effects for health due to their biological activities. Carotenoids are essential nutrients for mammals, but they are unable to synthesize them; instead, a dietary intake of these compounds is required. Carotenoids are classified as carotenes (hydrocarbon carotenoids), such as α- and ß-carotene, and xanthophylls (oxygenate derivatives) including zeaxanthin, astaxanthin, fucoxanthin, lutein, α- and ß-cryptoxanthin, and canthaxanthin. This review summarizes the present up-to-date knowledge of the anti-inflammatory and anticancer activities of microalgal carotenoids both in vitro and in vivo, as well as the latest status of human studies for their potential use in prevention and treatment of inflammatory diseases and cancer.

Anti-Inflammatory Effects of Rosmarinic Acid-Loaded Nanovesicles in Acute Colitis through Modulation of NLRP3 Inflammasome.

Ulcerative colitis (UC), one of the two main types of inflammatory bowel disease, has no effective treatment. Rosmarinic acid (RA) is a polyphenol that, when administered orally, is metabolised in the small intestine, compromising its beneficial effects. We used chitosan/nutriose-coated niosomes loaded with RA to protect RA from gastric degradation and target the colon and evaluated their effect on acute colitis induced by 4% dextran sodium sulphate (DSS) for seven days in mice. RA-loaded nanovesicles (5, 10 and 20 mg/kg) or free RA (20 mg/kg) were orally administered from three days prior to colitis induction and during days 1, 3, 5 and 7 of DSS administration. RA-loaded nanovesicles improved body weight loss and disease activity index as well as increased mucus production and decreased myeloperoxidase activity and TNF-α production. Moreover, RA-loaded nanovesicles downregulated protein expression of inflammasome components such as NLR family pyrin domain-containing 3 (NLRP3), adaptor protein (ASC) and caspase-1, and the consequent reduction of IL-1ß levels. Furthermore, nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) protein expression increased after the RA-loaded nanovesicles treatment However, these mechanistic changes were not detected with the RA-free treatment. Our findings suggest that the use of chitosan/nutriose-coated niosomes to increase RA local bioavailability could be a promising nutraceutical strategy for oral colon-targeted UC therapy.

Polyphenolic Maqui Extract as a Potential Nutraceutical to Treat TNBS-Induced Crohn's Disease by the Regulation of Antioxidant and Anti-Inflammatory Pathways.

Nutraceuticals include a wide variety of bioactive compounds, such as polyphenols, which have been highlighted for their remarkable health benefits. Specially, maqui berries have shown great antioxidant activity and anti-inflammatory effects on some inflammatory diseases. The objectives of the present study were to explore the therapeutic effects of maqui berries on acute-phase inflammation in Crohn's disease. Balb/c mice were exposed to 2,4,6-trinitrobenzene sulfonic acid (TNBS) via intracolonic administration. Polyphenolic maqui extract (Ach) was administered orally daily for 4 days after TNBS induction (Curative Group), and for 7 days prior to the TNBS induction until sacrifice (Preventive Group). Our results showed that both preventive and curative Ach administration inhibited body weight loss and colon shortening, and attenuated the macroscopic and microscopic damage signs, as well as significantly reducing transmural inflammation and boosting the recovery of the mucosal architecture and its muco-secretory function. Additionally, Ach promotes macrophage polarization to the M2 phenotype and was capable of down-regulating significantly the expression of inflammatory proteins COX-2 and iNOS, and at the same time it regulates the antioxidant Nrf-2/HO-1 pathway. In conclusion, this is the first study in which it is demonstrated that the properties of Ach as could be used as a preventive and curative treatment in Crohn's disease.

Fucoxanthin and Rosmarinic Acid Combination Has Anti-Inflammatory Effects through Regulation of NLRP3 Inflammasome in UVB-Exposed HaCaT Keratinocytes.

Excessive exposure to ultraviolet (UV) radiation is the main risk factor to develop skin pathologies or cancer because it encourages oxidative condition and skin inflammation. In this sense, strategies for its prevention are currently being evaluated. Natural products such as carotenoids or polyphenols, which are abundant in the marine environment, have been used in the prevention of oxidative stress due to their demonstrated antioxidant activities. Nevertheless, the anti-inflammatory activity and its implication in photo-prevention have not been extensively studied. Thus, we aimed to evaluate the combination of fucoxanthin (FX) and rosmarinic acid (RA) on cell viability, apoptosis induction, inflammasome regulation, and anti-oxidative response activation in UVB-irradiated HaCaT keratinocytes. We demonstrated for the first time that the combination of FX and RA (5 µM RA plus 5 µM FX, designated as M2) improved antioxidant and anti-inflammatory profiles in comparison to compounds assayed individually, by reducing UVB-induced apoptosis and the consequent ROS production. Furthermore, the M2 combination modulated the inflammatory response through down-regulation of inflammasome components such as NLRP3, ASC, and Caspase-1, and the interleukin (IL)-1ß production. In addition, Nrf2 and HO-1 antioxidant genes expression increased in UVB-exposed HaCaT cells pre-treated with M2. These results suggest that this combination of natural products exerts photo-protective effects by down-regulating NRLP3-inflammasome and increasing Nrf2 signalling pathway.

Fucoxanthin-Containing Cream Prevents Epidermal Hyperplasia and UVB-Induced Skin Erythema in Mice.

Microalgae represent a source of bio-active compounds such as carotenoids with potent anti-inflammatory and antioxidant properties. We aimed to investigate the effects of fucoxanthin (FX) in both in vitro and in vivo skin models. Firstly, its anti-inflammatory activity was evaluated in LPS-stimulated THP-1 macrophages and TNF-α-stimulated HaCaT keratinocytes, and its antioxidant activity in UVB-irradiated HaCaT cells. Next, in vitro and ex vivo permeation studies were developed to determine the most suitable formulation for in vivo FX topical application. Then, we evaluated the effects of a FX-containing cream on TPA-induced epidermal hyperplasia in mice, as well as on UVB-induced acute erythema in hairless mice. Our results confirmed the in vitro reduction of TNF-α, IL-6, ROS and LDH production. Since the permeation results showed that cream was the most favourable vehicle, FX-cream was elaborated. This formulation effectively ameliorated TPA-induced hyperplasia, by reducing skin edema, epidermal thickness, MPO activity and COX-2 expression. Moreover, FX-cream reduced UVB-induced erythema through down-regulation of COX-2 and iNOS as well as up-regulation of HO-1 protein via Nrf-2 pathway. In conclusion, FX, administered in a topical formulation, could be a novel natural adjuvant for preventing exacerbations associated with skin inflammatory pathologies as well as protecting skin against UV radiation.

Microalgae-derived oxylipins decrease inflammatory mediators by regulating the subcellular location of NFκB and PPAR-γ.

Oxylipins (OXLs) are bioactive molecules generated by the oxidation of fatty acids that promote the resolution of acute inflammation and prevent chronic inflammatory processes through molecular mechanisms that are not well known. We have previously reported the anti-inflammatory activity of microalgae-derived OXLs and OXL-containing biomass in two inflammatory bowel disease (IBD) models: 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced acute colitis and TNBS-induced recurrent colitis. In this study, we examined the in vitro anti-inflammatory mechanism of action of the most abundant OXLs isolated from Chlamydomonas debaryana (13S-HOTE and 13S-HODE) and Nannochloropsis gaditana (15S-HEPE). These OXLs decreased IL-1ß and IL-6 pro-inflammatory cytokines production as well as iNOS and COX-2 expression levels in THP-1 macrophages. In addition, OXLs decreased IL-8 production in HT-29 colon cells, the major chemokine produced by these cells. The interaction of OXLs with NFκB and PPAR-γ signaling pathways was studied by confocal microscopy. In THP-1 macrophages and HT-29 colon cells, stimulated by LPS and TNFα respectively, a pre-treatment with 13S-HOTE, 13S-HODE and 15S-HEPE (100µM) resulted in a lower nuclear presence of NFκB in both cell lines. The study of the subcellular localization of PPAR-γ showed that the treatment of THP-1 and HT-29 cells with these OXLs caused the migration of PPAR-γ into the nucleus. Colocalization analysis of both transcription factors in LPS-stimulated THP-1 macrophages showed that the pre-treatment with 13S-HOTE, 13S-HODE or 15S-HEPE lowered nuclear colocalization similar to control value, and increased cytosolic localization above control level. These results indicate that these OXLs could act as agonist of PPAR-γ and consequently inhibit NFκB signaling pathway activation, thus lowering the production of inflammatory markers, highlighting the therapeutic potential of these OXLs in inflammatory diseases such as IBD.

Dual Effects of Resveratrol on Cell Death and Proliferation of Colon Cancer Cells.

Colorectal cancer remains a main cause of deaths worldwide, and novel agents are being searched to treat this disease. Polyphenols have emerged as promising therapeutic tools in cancer. Resveratrol (3,5,4'-trihydoxy-trans-stilbene) induces cell death in different tumor cell lines, and it also stimulates the proliferation of specific breast and prostate cancer cell lines. Here, we studied the impact of resveratrol over a 100-fold concentration range on cell death and proliferation of HT-29 colorectal adenocarcinoma cells. After 96 h of treatment, a biphasic pattern was observed. At lower concentrations (1 and 10 µmol/l), resveratrol increased the cell number, as did the polyphenol quercetin. At 50 or 100 µmol/l, resveratrol reduced the cell number and increased the percentage of apoptotic or necrotic cells, thus indicating cytotoxicity. On HCT116 colon cancer cells, however, no proliferative properties of resveratrol were observed. Resveratrol-induced cytotoxicity on HT-29 cells was associated with NADPH oxidase activation and increased levels of histone γH2AX, a marker of DNA damage, paralleled by enhanced sirtuin 6 levels, likely as a repair mechanism. Overall, resveratrol may be an effective tool in anti-tumor chemotherapy. However, since under some conditions it may favor tumor cell growth, appropriate local concentrations must be achieved to minimize unwanted effects of resveratrol.

Molecular Characterization and Anti-inflammatory Activity of Galactosylglycerides and Galactosylceramides from the Microalga Isochrysis galbana.

Isochrysis galbana is a marine microalga rich in PUFAs that is widely used as feed in aquaculture and more recently investigated for its potential in food applications and as source of bioactive compounds. In this study, the biomass obtained from cultures of I. galbana has been investigated to determine its content in glycosylglycerides and glycosylceramides. By using NMR, UPLC-MS/MS, and fatty acid profiles, the structures of ten monogalactosyldiacylglycerols (MGDGs 1-10) and nine digalactosyldiacylglycerols (DGDGs 11-19) have been established. Two distinctive features of the galactosylglycerides from I. galbana are the wide presence of highly unsaturated acyl chains derived from stearidonic acid (18:4Δ6Z,9Z,12Z,15Z) and octadecapentaenoic acid (18:5Δ3Z,6Z,9Z,12Z,15Z), as well as the unusual coexistence of αß-DGDGs and ßß-DGDGs. Three new galactosylceramides, isogalbamides A-C (20-22), have also been isolated and characterized by NMR and MS/MS. These metabolites, which are the first galactosylceramides described from microalgae, derive from unprecedented tetraolefinic sphingoid bases. In anti-inflammatory assays, the MGDG and DGDG mixtures and the isolated DGDGs 11 and 12 showed significant activity as inhibitors of the production of the pro-inflammatory cytokine TNF-α in lipopolysaccharide-stimulated human THP-1 macrophages, while the galactosylceramides showed moderated activity.

The Algal Meroterpene 11-Hydroxy-1'-O-Methylamentadione Ameloriates Dextran Sulfate Sodium-Induced Colitis in Mice.

Inflammatory bowel disease (IBD) is a complex class of immune disorders. Unfortunately, a treatment for total remission has not yet been found, while the use of natural product-based therapies has emerged as a promising intervention. The present study was aimed to investigate the anti-inflammatory effects of the algal meroterpene 11-hydroxy-1'-O-methylamentadione (AMT-E) in a murine model of dextran sodium sulphate (DSS)-induced colitis. AMT-E was orally administered daily (1, 10, and 20 mg/kg animal) to DSS treated mice (3% w/v) for 7 days. AMT-E prevented body weight loss and colon shortening and effectively attenuated the extent of the colonic damage. Similarly, AMT-E increased mucus production and reduced myeloperoxidase activity (marker for anti-inflammatory activity). Moreover, the algal meroterpene decreased the tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-10 levels, and caused a significant reduction of the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Our results demonstrate the protective effects of AMT-E on experimental colitis, provide an insight of the underlying mechanisms of this compound, and suggest that this class of marine natural products might be an interesting candidate for further studies on the prevention/treatment of IBD.

Expression patterns of sirtuin 1-AMPK-autophagy pathway in chronic colitis and inflammation-associated colon neoplasia in IL-10-deficient mice.

BACKGROUND: Interleukin-10-deficient (IL-10 (-/-)) mice spontaneously develop chronic colitis and adenocarcinoma through the dysplasia sequence. Autophagy malfunction is associated to inflammatory bowel disease (IBD) and colorectal cancer (CRC) pathogenesis. Autophagy is regulated by silent information regulator-1 (SIRT1), a NAD+-dependent histone deacetylase. Our aim was to investigate the expression changes of SIRT1-AMPK-autophagy pathway in the progression from chronic colitis to CRC. METHODS: We studied C57BL/6-IL-10-deficient mice between 6 and 18weeks of age. Macroscopic and histological analysis, and characterization of inflammatory and tumor biomarkers were performed. RESULTS: IL-10-deficient mice developed colitis from the age of 6weeks onward. The severity of inflammation and dysplasia, and the proliferative activity increased gradually with age. IL-10 (-/-) mice were characterized by improved levels of TNF-α and decreased expression of SIRT1. Moreover, our findings show an increase in p-AMPK expression and an activation of the autophagy in IL-10 (-/-) mice from all stages, evidenced by the accumulation of LC3-II protein, the increase in Beclin 1 expression and the reduction in Bcl-2 levels. CONCLUSIONS: SIRT1-AMPK-autophagy pathway may be involved in the maintenance of chronic inflammation and dysplasia development in the IL-10-deficient mice model. Modulation of this pathway could be a novel strategy for IBD and CRC treatment.

Goniothalamin prevents the development of chemically induced and spontaneous colitis in rodents and induces apoptosis in the HT-29 human colon tumor cell line.

Colon cancer is the third most incident type of cancer worldwide. One of the most important risk factors for colon cancer development are inflammatory bowel diseases (IBD), thus therapies focusing on IBD treatment have great potential to be used in cancer prevention. Nature has been a source of new therapeutic and preventive agents and the racemic form of the styryl-lactone goniothalamin (GTN) has been shown to be a promising antiproliferative agent, with gastroprotective, antinociceptive and anti-inflammatory effects. As inflammation is a well-known tumor promoter, the major goal of this study was to evaluate the therapeutic and preventive potentials of GTN on chemically induced and spontaneous colitis, as well as the cytotoxic effects of GTN on a human colon tumor cell line (HT-29). GTN treatments inhibited TNBS-induced acute and chronic colitis development in Wistar rats, reducing myeloperoxidase levels and inflammatory cells infiltration in the mucosa. In spontaneous-colitis using IL-10 deficient mice (C57BL/6 background), GTN prevented colitis development through downregulation of TNF-α, upregulation of SIRT-1 and inhibition of proliferation (PCNA index), without signs of toxicity after three months of treatment. In HT-29 cells, treatment with 10µM of GTN induced apoptosis by increasing BAX/BCL2, p-JNK1/JNK1, p-P38/P38 ratios as well as through ROS generation. Caspase 8, 9 and 3 activation also occurred, suggesting caspase-dependent apoptotic pathway, culminating in PARP-1 cleavage. Together with previous data, these results show the importance of GTN as a pro-apoptotic, preventive and therapeutic agent for IBD and highlight its potential as a chemopreventive agent for colon cancer.

Cytotoxic Activity of Microalgal-derived Oxylipins against Human Cancer Cell lines and their Impact on ATP Levels.

Oxylipins are metabolites derived from lipid peroxidation. The plant oxylipin methyl jasmonate (MJ) shows cytotoxic activity against cancer cell lines of various origins, with ATP-depletion being one of the mechanisms responsible for this effect. The cytotoxic activity of oxylipins (OXLs) isolated from the microalgae Chlamydomonas debaryana (13-HOTE) and Nannochloropsis gaditana (15-HEPE) was higher against UACC-62 (melanoma) than towards HT-29 (colon adenocarcinoma) cells. OXLs lowered the ATP levels of HT-29 and UACC-62 cells, but the effect was higher on the second cell line, which had higher basal ATP. This result proves a link between the cytotoxicity and the capability of these compounds to deplete ATP. In addition, the combination of 13-HOTE with the anticancer drug 5-fluorouracil (5-FU) induced a synergistic toxicity against HT-29 cells. These results highlight the therapeutic potential of oxylipins derived from microalgae.

Bioactive Compounds Isolated from Microalgae in Chronic Inflammation and Cancer.

The risk of onset of cancer is influenced by poorly controlled chronic inflammatory processes. Inflammatory diseases related to cancer development include inflammatory bowel disease, which can lead to colon cancer, or actinic keratosis, associated with chronic exposure to ultraviolet light, which can progress to squamous cell carcinoma. Chronic inflammatory states expose these patients to a number of signals with tumorigenic effects, including nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPK) activation, pro-inflammatory cytokines and prostaglandins release and ROS production. In addition, the participation of inflammasomes, autophagy and sirtuins has been demonstrated in pathological processes such as inflammation and cancer. Chemoprevention consists in the use of drugs, vitamins, or nutritional supplements to reduce the risk of developing or having a recurrence of cancer. Numerous in vitro and animal studies have established the potential colon and skin cancer chemopreventive properties of substances from marine environment, including microalgae species and their products (carotenoids, fatty acids, glycolipids, polysaccharides and proteins). This review summarizes the main mechanisms of actions of these compounds in the chemoprevention of these cancers. These actions include suppression of cell proliferation, induction of apoptosis, stimulation of antimetastatic and antiangiogenic responses and increased antioxidant and anti-inflammatory activity.

Protective effect of polyphenols in an inflammatory process associated with experimental pulmonary fibrosis in mice.

Polyphenols have been described to have a wide range of biological activities, and many reports, published during recent years, have highlighted the beneficial effects of phenolic compounds, illustrating their promising role as therapeutic tools in several acute and chronic disorders. The purpose of study was to evaluate, in an already-assessed model of lung injury caused by bleomycin (BLM) administration, the role of resveratrol and quercetin, as well as to explore the potential beneficial properties of a mango leaf extract, rich in mangiferin, and a grape leaf extract, rich in dihydroquercetin (DHQ), on the same model. Mice were subjected to intra-tracheal administration of BLM, and polyphenols were administered by oral route immediately after BLM instillation and daily for 7 d. Treatment with resveratrol, mangiferin, quercetin and DHQ inhibited oedema formation and body weight loss, as well as ameliorated polymorphonuclear infiltration into the lung tissue and reduced the number of inflammatory cells in bronchoalveolar lavage fluid. Moreover, polyphenols suppressed inducible nitric oxide synthase expression, and prevented oxidative and nitroxidative lung injury, as shown by the reduced nitrotyrosine and poly (ADP-ribose) polymerase levels. The degree of apoptosis, as evaluated by Bid and Bcl-2 balance, was also suppressed after polyphenol treatment. Finally, these natural products down-regulated cyclo-oxygenase-2, extracellular signal-regulated kinase phosphorylated expression and reduced NF-κBp65 translocation. Our findings confirmed the anti-inflammatory effects of resveratrol and quercetin in BLM-induced lung damage, and highlight, for the first time, the protective properties of exogenous administration of mangiferin and DHQ on experimental pulmonary fibrosis.

Inhibition of chronic ulcerative colitis-associated adenocarcinoma development in mice by VSL#3.

BACKGROUND: Colorectal cancer is the most severe complication in inflammatory bowel disease. This study aimed to investigate the effects of the probiotic VSL#3 when administered as either preventive or concurrent treatment in the progression from chronic colitis to colon cancer. METHODS: Mice were exposed to 5, 10, and 15 cycles of dextran sulfate sodium (DSS); each cycle consisted of 0.7% DSS for 1 week followed by distilled water for 10 days. VSL#3 was administered either from 2 weeks before the colitis induction or from the first day of the colitis until being killed. After each period, macroscopic and histological studies, as well as analysis of inflammatory and tumor biomarkers, were performed. RESULTS: Prophylactic or concurrent VSL#3 administration attenuated the disease activity index score and colon inflammation after 5, 10, and 15 cycles of DSS, as well as reduced the histological alterations and the incidence of colonic dysplastic lesions at the 3 periods studied. None of the animals receiving VSL#3 as a concurrent treatment developed carcinoma, which is in contrast to 5% and 20% of the mice following preventive VSL#3 administration, developing carcinoma at the 10th and the 15th cycles of DSS, respectively. In addition, the probiotic reduced the proliferating cell nuclear antigen labeling index, tumor necrosis factor alpha, interleukin-1ß, interleukin-6 production, cyclooxygenase-2 expression, and increased interleukin-10 levels in colon tissue at the 3 periods assayed. CONCLUSIONS: VSL#3 administration reduced chronic inflammation and prevented or delayed the development of dysplasia and carcinoma in a mouse model of chronic colitis-associated cancer.

Preventive effect of the microalga Chlamydomonas debaryana on the acute phase of experimental colitis in rats.

Inflammatory bowel diseases (IBD) are characterised by chronic uncontrolled inflammation of intestinal mucosa. Diet and nutritional factors have emerged as possible interventions for IBD. Microalgae are rich sources of n-3 PUFA and derived oxylipins. Oxylipins are lipid mediators involved in the resolution of many inflammatory disorders. The aim of the present study was to investigate the effects of the oxylipin-containing biomass of the microalga Chlamydomonas debaryana and its major oxylipin constituent, (9Z,11E,13S,15Z)-13-hydroxyoctadeca-9,11,15-trienoic acid ((13S)-HOTE), on acute 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in rats. Lyophilised microalgal biomass and (13S)-HOTE were administered by oral route 48, 24 and 1 h before the induction of colitis and 24 h later, and the rats were killed after 48 h. The treatment with the lyophilised microalga and (13S)-HOTE improved body-weight loss and colon shortening, as well as attenuated the extent of colonic damage and increased mucus production. Cellular neutrophil infiltration, with the subsequent increase in myeloperoxidase levels induced by TNBS, were also reduced after the administration of the lyophilised microalga or (13S)-HOTE. The anti-inflammatory effects of these treatments were confirmed by the inhibition of colonic TNF-α production. Moreover, lyophilised microalga or (13S)-HOTE down-regulated cyclo-oxygenase-2 and inducible nitric oxide synthase expression. The present study was the first to show the prophylactic effects of a lyophilised biomass sample of the microalga C. debaryana and the oxylipin (13S)-HOTE on TNBS-induced acute colitis in rats. Our findings suggest that the microalga C. debaryana or derived oxylipins could be used as nutraceuticals in the treatment of the active phase of IBD.

Chemoprevention with phytonutrients and microalgae products in chronic inflammation and colon cancer.

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder caused by deregulated immune responses in a genetically predisposed individual. This is a complex process mediated by cytokines, chemokines, adhesion molecules, cytoplasm nuclear receptors, among others. Recent data support a participation of the endoplasmic reticulum (ER) stress and mitochondrial dysfunctions in IBD. Moreover, now it is evident that chronic degenerative pathologies, including IBD, share comparable disease mechanisms at the cellular level with alteration of the autophagy mechanisms. Mounting evidence suggests that the risk of developing colorectal cancer (CRC) is dramatically increased in patients with chronic inflammatory disease. Chronic inflammation in IBD exposes these patients to a number of signals known to have tumorigenic effects including nuclear factor kappa B (NF-κB) activation, proinflammatory cytokines and prostaglandins release and reactive oxygen species (ROS) production. Chemoprevention consists in the use of drugs, vitamins, or nutritional supplements to reduce the risk of developing, or having a recurrence of cancer. Numerous in vitro and animal studies have established the potential colon cancer chemopreventive properties of phytochemicals derived from both plants (curcumin, resveratrol, epigallocatechin gallate, quercetin or genistein) and substances from marine environment, including microalgae species and their products. This review summarizes the mechanisms by which these naturally occurring compounds may mediate chemopreventive effects on cancer. These actions include induction of cell cycle arrest and apoptosis, inhibition of cell proliferation, stimulation of antimetastatic and antiangiogenic responses and increased antioxidant and anti-inflammatory activity.

ß-catenin represses expression of the tumour suppressor 15-prostaglandin dehydrogenase in the normal intestinal epithelium and colorectal tumour cells.

BACKGROUND: Cyclooxygenase-2 (COX-2) overexpression in colorectal cancer increases levels of its pro-tumorigenic product prostaglandin E2 (PGE(2)). The recently identified colorectal tumour suppressor 15-prostaglandin dehydrogenase (15-PGDH) catalyses prostaglandin turnover and is downregulated at a very early stage in colorectal tumorigenesis; however, the mechanism responsible remains unclear. As Wnt/ß-catenin signalling is also deregulated early in colorectal neoplasia, a study was undertaken to determine whether ß-catenin represses 15-PGDH expression. METHODS: The effect of modulating Wnt/ß-catenin signalling (using ß-catenin siRNA, mutant TCF4, Wnt3A or GSK3 inhibition) on 15-PGDH mRNA, protein expression and promoter activity was determined in colorectal cell lines by immunoblotting, qRT-PCR and reporter assays. The effect of ß-catenin deletion in vivo was addressed by 15-PGDH immunostaining of ß-catenin(-/lox)-villin-creERT2 mouse tissue. 15-PGDH promoter occupancy was determined using chromatin immunoprecipitation and PGE(2) levels by ELISA. RESULTS: The study shows for the first time that ß-catenin knockdown upregulates 15-PGDH in colorectal adenoma and carcinoma cells without affecting COX-2 protein levels. A dominant negative mutant form of TCF4 (dnTCF4), unable to bind ß-catenin, also upregulated 15-PGDH; conversely, increasing ß-catenin activity using Wnt3A or GSK3 inhibition downregulated 15-PGDH. Importantly, inducible ß-catenin deletion in vivo also upregulated intestinal epithelial 15-PGDH. 15-PGDH regulation occurred at the protein, mRNA and promoter activity levels and chromatin immunoprecipitation indicated ß-catenin/TCF4 binding to the 15-PGDH promoter. ß-catenin knockdown decreased PGE(2) levels, and this was significantly rescued by 15-PGDH siRNA. CONCLUSION: These data suggest a novel role for ß-catenin in promoting colorectal tumorigenesis through very early 15-PGDH suppression leading to increased PGE(2) levels, possibly even before COX-2 upregulation.