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1.  Crosstalk between Helicobacter pylori and Gastric Epithelial Cells Is Impaired by Docosahexaenoic Acid 
PLoS ONE  2013;8(4):e60657.
H. pylori colonizes half of the world's population leading to gastritis, ulcers and gastric cancer. H. pylori strains resistant to antibiotics are increasing which raises the need for alternative therapeutic approaches. Docosahexaenoic acid (DHA) has been shown to decrease H. pylori growth and its associated-inflammation through mechanisms poorly characterized. We aimed to explore DHA action on H. pylori-mediated inflammation and adhesion to gastric epithelial cells (AGS) and also to identify bacterial structures affected by DHA. H. pylori growth and metabolism was assessed in liquid cultures. Bacterial adhesion to AGS cells was visualized by transmission electron microscopy and quantified by an Enzyme Linked Immunosorbent Assay. Inflammatory proteins were assessed by immunoblotting in infected AGS cells, previously treated with DHA. Bacterial total and outer membrane protein composition was analyzed by 2-dimensional gel electrophoresis. Concentrations of 100 µM of DHA decreased H. pylori growth, whereas concentrations higher than 250 µM irreversibly inhibited bacteria survival. DHA reduced ATP production and adhesion to AGS cells. AGS cells infected with DHA pre-treated H. pylori showed a 3-fold reduction in Interleukin-8 (IL-8) production and a decrease of COX2 and iNOS. 2D electrophoresis analysis revealed that DHA changed the expression of H. pylori outer membrane proteins associated with stress response and metabolism and modified bacterial lipopolysaccharide phenotype. As conclusions our results show that DHA anti-H. pylori effects are associated with changes of bacteria morphology and metabolism, and with alteration of outer membrane proteins composition, that ultimately reduce the adhesion of bacteria and the burden of H. pylori-related inflammation.
PMCID: PMC3618039  PMID: 23577140
2.  Influence of inflammatory cytokine polymorphisms on eradication rates of Helicobacter pylori 
Pro-inflammatory cytokines and anti-inflammatory cytokines are produced in gastric mucosa from inflammatory cells activated by Helicobacter pylori (H. pylori) infection. Of the inflammatory cytokines, interleukin (IL)-1β and tumor necrosis factor (TNF)-α have a potent inhibitive effect on gastric acid production. Polymorphisms in these genes are associated with individual differences in cytokine messenger RNA levels, which result in different gastric mucosal inflammation, different acid inhibition and different gastroduodenal disease risks in response to H. pylori infection. The sustained higher intragastric pH during an eradication therapy is known to be one of the therapeutic determinants of the H. pylori eradication as well as antibiotics resistance and poor compliance. The IL-1B-511 polymorphism is related to eradication rate, and, in combined analysis of previous reports, the eradication rate in patients with the IL-1B-511 C/C genotype (77.4%, 209/270), low IL-1β producer genotype, is lower than that of the IL-1B-511 C/T and T/T genotypes (87.2%, 631/724) (Odds ratio for eradication failure: 1.98, 95% confidence interval: 1.38–2.84, P = 0.0002). Moreover, the odds ratio of combined CYP2C19 rapid metabolizer-IL-1B-511 C/C type for eradication failure is 11.15 (5.23–23.78) times that of the CYP2C19 poor metabolizer-IL-1B-511 non-C/C type. However, there is no positive data indicating the role of other inflammatory cytokine polymorphisms (e.g. IL-1RN, TNF-A or IL-10) in eradication therapy. Nevertheless, the studies show that inflammatory cytokine polymorphisms, especially the IL-1B-511 T/T genotype, are the determinants of eradication by affecting gastric acid secretion and mucosal inflammation. Therefore, the tailored eradication therapy, considering inflammatory cytokine polymorphisms, may be effective for the higher eradication rates.
PMCID: PMC3128255  PMID: 20136959
eradication therapy; Helicobacter pylori; IL-1β; inflammatory cytokine; polymorphism; TNF-α
3.  The Effects of EPA+DHA and Aspirin on Inflammatory Cytokines and Angiogenesis Factors 
In a recent study, we showed that the combination of aspirin plus the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) synergistically inhibited platelet function. As aspirin, EPA, and DHA have demonstrated anti-inflammatory properties, we hypothesized that the ingestion of EPA and DHA, with and without aspirin, would reduce plasma levels of inflammatory cytokines and angiogenesis factors more than aspirin alone and before aspirin was ingested.
Using multiplex technology, we investigated the effects of aspirin (single-dose 650 mg on day 1), EPA+DHA (3.4 g/d for days 2-29), and aspirin with EPA+DHA (day 30) on plasma levels of inflammatory cytokines and angiogenesis factors in healthy adults.
Aspirin alone had no effect on any factor versus baseline, but EPA+DHA, with and without aspirin, significantly reduced concentrations of 8 of 9 factors. Although EPA+DHA plus aspirin reduced concentrations of a subset of the factors compared to baseline, neither aspirin alone nor the combination significantly reduced the level of any analyte more robustly than EPA+DHA alone.
These data suggest that EPA+DHA has more pronounced down-regulatory effects on inflammation and angiogenesis than aspirin. The implications of these findings for the use of combined therapy for cardiovascular disease remain to be clarified.
PMCID: PMC3331709  PMID: 22530200
eicosapentaenoic acid; docosahexaenoic acid; lipid mediators; fatty acids; angiogenesis; hemostasis; platelet function; cytokines; aspirin
4.  Inhibitory effects of docosahexaenoic acid on colon carcinoma 26 metastasis to the lung. 
British Journal of Cancer  1997;75(5):650-655.
Unsaturated fatty acids, including n-3 polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (C22:6, DHA) and eicosapentaenoic acid (C20:5, EPA), and a series of n-6 PUFAs were investigated for their anti-tumour and antimetastatic effects in a subcutaneous (s.c.) implanted highly metastatic colon carcinoma 26 (Co 26Lu) model. EPA and DHA exerted significant inhibitory effects on tumour growth at the implantation site and significantly decreased the numbers of lung metastatic nodules. Oleic acid also significantly inhibited lung metastatic nodules. Treatment with arachidonic acid showed a tendency for reduction in colonization. However, treatment with high doses of fatty acids, especially linoleic acid, increased the numbers of lung metastatic nodules. DHA and EPA only inhibited lung colonizations when administered together with the tumour cells, suggesting that their incorporation is necessary for an influence to be exerted. Chromatography confirmed that contents of fatty acids in both tumour tissues and plasma were indeed affected by the treatments. Tumour cells pretreated with fatty acids in vivo, in particular DHA, also showed a low potential for lung colony formation when transferred to new hosts. Thus, DHA treatment exerted marked antimetastatic activity associated with pronounced change in the fatty acid component of tumour cells. The results indicate that uptake of DHA into tumour cells results in altered tumour cell membrane characteristics and a decreased ability to metastasize.
PMCID: PMC2063338  PMID: 9043019
5.  Anti-Helicobacter pylori Properties of GutGard™ 
Presence of Helicobacter pylori is associated with an increased risk of developing upper gastrointestinal tract diseases. Antibiotic therapy and a combination of two or three drugs have been widely used to eradicate H. pylori infections. Due to antibiotic resistant drugs, new drug resources are needed such as plants which contain antibacterial compounds. The aim of this study was to investigate the ability of GutGard™ to inhibit H. pylori growth both in Mongolian gerbils and C57BL/6 mouse models. Male Mongolian gerbils were infected with the bacteria by intragastric inoculation (2×109 CFU/gerbil) 3 times over 5 days and then orally treated once daily 6 times/week for 8 weeks with 15, 30 and 60 mg/kg GutGard™. After the final administration, biopsy samples of the gastric mucosa were assayed for bacterial identification via urease, catalase and ELISA assays as well as immunohistochemistry (IHC). In the Mongolian gerbil model, IHC and ELISA assays revealed that GutGard™ inhibited H. pylori colonization in gastric mucosa in a dose dependent manner. The anti-H. pylori effects of GutGard™ in H. pylori-infected C57BL/6 mice were also examined. We found that treatment with 25 mg/kg GutGard™ significantly reduced H. pylori colonization in mice gastric mucosa. Our results suggest that GutGard™ may be useful as an agent to prevent H. pylori infection.
PMCID: PMC3892500  PMID: 24471118
H. pylori; G. glabra; gastric mucosa; colonization
6.  Oral Supplementation with Docosahexaenoic Acid and Uridine-5’-Monophosphate Increases Dendritic Spine Density in Adult Gerbil Hippocampus 
Brain research  2007;1182:50-59.
Docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid, is an essential component of membrane phosphatides and has been implicated in cognitive functions. Low levels of circulating or brain DHA are associated with various neurocognitive disorders including Alzheimer’s disease (AD), while laboratory animals, including animal models of AD, can exhibit improved cognitive ability with a diet enriched in DHA. Various cellular mechanisms have been proposed for DHA’s behavioral effects, including increases in cellular membrane fluidity, promotion of neurite extension, and inhibition of apoptosis. However, there is little direct evidence that DHA affects synaptic structure in living animals. Here we show that oral supplementation with DHA substantially increases the number of dendritic spines in adult gerbil hippocampus, particularly when animals are co-supplemented with a uridine source, uridine-5’-monophosphate (UMP), which increases brain levels of the rate-limiting phosphatide precursor CTP. The increase in dendritic spines (> 30%) is accompanied by parallel increases in membrane phosphatides, and in pre- and post-synaptic proteins within the hippocampus. Hence oral DHA may promote neuronal membrane synthesis to increase the number of synapses, particularly when co-administered with UMP. Our findings provide a possible explanation for the effects of DHA on behavior and also suggest a strategy to treat cognitive disorders resulting from synapse loss.
PMCID: PMC2140951  PMID: 17950710
docosahexaenoic acid; uridine; membrane synthesis; spine formation; synaptogenesis; phosphatides
7.  DHA Supplemented in Peptamen Diet Offers No Advantage in Pathways to Amyloidosis: Is It Time to Evaluate Composite Lipid Diet? 
PLoS ONE  2011;6(9):e24094.
Numerous reports have documented the beneficial effects of dietary docosahexaenoic acid (DHA) on beta-amyloid production and Alzheimer's disease (AD). However, none of these studies have examined and compared DHA, in combination with other dietary nutrients, for its effects on plaque pathogenesis. Potential interactions of DHA with other dietary nutrients and fatty acids are conventionally ignored. Here we investigated DHA with two dietary regimes; peptamen (pep+DHA) and low fat diet (low fat+DHA). Peptamen base liquid diet is a standard sole-source nutrition for patients with gastrointestinal dysfunction. Here we demonstrate that a robust AD transgenic mouse model shows an increased tendency to produce beta-amyloid peptides and amyloid plaques when fed a pep+DHA diet. The increase in beta-amyloid peptides was due to an elevated trend in the levels of beta-secretase amyloid precursor protein (APP) cleaving enzyme (BACE), the proteolytic C-terminal fragment beta of APP and reduced levels of insulin degrading enzyme that endoproteolyse beta-amyloid. On the contrary, TgCRND8 mice on low fat+DHA diet (based on an approximately 18% reduction of fat intake) ameliorate the production of abeta peptides and consequently amyloid plaques. Our work not only demonstrates that DHA when taken with peptamen may have a tendency to confer a detrimental affect on the amyloid plaque build up but also reinforces the importance of studying composite lipids or nutrients rather than single lipids or nutrients for their effects on pathways important to plaque development.
PMCID: PMC3169579  PMID: 21931647
8.  Docosahexaenoic acid suppresses arachidonic acid-induced proliferation of LS-174T human colon carcinoma cells 
AIM: To investigate the impact of arachidonic acid (AA) and docosahexaenoic acid (DHA) and their combination on colon cancer cell growth.
METHODS: The LS-174T colon cancer cell line was used to study the role of the prostaglandin precursor AA and the omega-3 polyunsaturated fatty acid DHA on cell growth. Cell viability was assessed in XTT assays. For analysis of cell cycle and cell death, flow cytometry and DAPI staining were applied. Expression of cyclooxygenase-2 (COX-2), p21 and bcl-2 in cells incubated with AA or DHA was examined by real-time RT-PCR. Prostaglandin E2 (PGE2) generation in the presence of AA and DHA was measured using a PGE2-ELISA.
RESULTS: AA increased cell growth, whereas DHA reduced viability of LS 174T cells in a time- and dose-dependent manner. Furthermore, DHA down- regulated mRNA of bcl-2 and up-regulated p21. Interestingly, DHA was able to suppress AA-induced cell proliferation and significantly lowered AA-derived PGE2 formation. DHA also down-regulated COX-2 expression. In addition to the effect on PGE2 formation, DHA directly reduced PGE2-induced cell proliferation in a dose-dependent manner.
CONCLUSION: These results suggest that DHA can inhibit the pro-proliferative effect of abundant AA or PGE2.
PMCID: PMC2655186  PMID: 19266600
Colorectal carcinoma; Colon cancer; Omega-3; Omega-6; Polyunsaturated fatty acids; Arachidonic acid; Docosahexaenoic acid; Prostaglandin E2; Cyclooxygenase-2; Apoptosis
9.  Docosahexaenoic Acid Induces Apoptosis in MCF-7 Cells In Vitro and In Vivo via Reactive Oxygen Species Formation and Caspase 8 Activation 
PLoS ONE  2010;5(4):e10296.
The present study sought to further investigate the in vitro and in vivo anticancer effects of a representative omega-3 fatty acid, docosahexaenoic acid (DHA), with a focus on assessing the induction of oxidative stress and apoptosis as an important mechanism for its anticancer actions.
Methodology/Principal Findings
In vitro studies showed that DHA strongly reduces the viability and DNA synthesis of MCF-7 human breast cancer cells in culture, and also promotes cell death via apoptosis. Mechanistically, accumulation of reactive oxygen species and activation of caspase 8 contribute critically to the induction of apoptotic cell death. Co-presence of antioxidants or selective inhibition or knockdown of caspase 8 each effectively abrogates the cytotoxic effect of DHA. Using athymic nude mice as an in vivo model, we found that feeding animals the 5% fish oil-supplemented diet for 6 weeks significantly reduces the growth of MCF-7 human breast cancer cells in vivo through inhibition of cancer cell proliferation as well as promotion of cell death. Using 3-nitrotyrosine as a parameter, we confirmed that the fish oil-supplemented diet significantly increases oxidative stress in tumor cells in vivo. Analysis of fatty acid content in plasma and tissues showed that feeding animals a 5% fish oil diet increases the levels of DHA and eicosapentaenoic acid in both normal and tumorous mammary tissues by 329% and 300%, respectively.
DHA can strongly induce apoptosis in human MCF-7 breast cancer cells both in vitro and in vivo. The induction of apoptosis in these cells is selectively mediated via caspase 8 activation. These observations call for further studies to assess the effectiveness of fish oil as a dietary supplement in the prevention and treatment of human breast cancer.
PMCID: PMC2858652  PMID: 20421971
10.  Alzheimer’s Disease: Fatty Acids We Eat may be Linked to a Specific Protection via Low-dose Aspirin 
Aging and Disease  2010;1(1):37-59.
It has been suggested that cognitive decline in aging is the consequence of a growing vulnerability to an asymptomatic state of neuroinflammation. Moreover, it is becoming more evident that inflammation occurs in the brain of Alzheimer’s disease (AD) patients and that the classical mediators of inflammation, eicosanoids and cytokines, may contribute to the neurodegeneration. In agreement with this observation, aspirin (ASA) - a non-steroidal anti-inflammatory drug - may protect against AD and/or vascular dementia. However, both the time of prescription and the dose of ASA may be critical. A major indication for low-dose ASA is in combination with docosahexaenoic acid (DHA). DHA plays an essential role in neural function and its anti-inflammatory properties are associated with the well-known ability of this fatty acid to inhibit the production of various pro-inflammatory mediators, including eicosanoids and cytokines. Higher DHA intake is inversely correlated with relative risk of AD and DHA+ASA supplement may further decrease cognitive decline in healthy elderly adults. Although low-dose ASA may be insufficient for any anti-inflammatory action the concomitant presence of DHA favours a neuroprotective role for ASA. This depends on the allosteric effects of ASA on cyclooxygenase-2 and following production - from DHA - of specific lipid mediators (resolvins, protectins, and electrophilic oxo-derivatives). ASA and DHA might protect against AD, although controlled trials are warranted.
PMCID: PMC3295019  PMID: 22396856
Cytokines; docosahexaenoic acid (DHA); aspirin (ASA); resolvins; neuroprotectin D1 (NPD1); nonsteroidal anti-inflammatory drugs (NSAIDs); primary prevention
11.  Matrix metalloproteinase-7 and premalignant host responses in Helicobacter pylori-infected mice 
Cancer research  2010;70(1):30-35.
Helicobacter pylori-induced gastritis is the strongest singular risk factor for gastric adenocarcinoma. Matrix metalloproteinase-7, MMP-7, is a proteolytic enzyme that can modify the intestinal microbial replicative niche as well as affect tumorigenesis and H. pylori stimulates expression of MMP-7 in gastric epithelial cells in vitro. Utilizing a transgenic murine model of H. pylori-mediated injury, our experiments now demonstrate that gastric inflammation is increased within the context of MMP-7 deficiency, which involves both Th1- and Th17-mediated pathways. Enhanced gastritis in H. pylori-infected mmp-7−/− mice is strongly linked to accelerated epithelial cellular turnover. However, more severe inflammation and heightened proliferation and apoptosis are not dependent on MMP-7-mediated bacterial eradication. Collectively, these studies indicate that H. pylori-mediated induction of MMP-7 may serve to protect the gastric mucosa from pathophysiological processes that promote carcinogenesis.
PMCID: PMC2804939  PMID: 20048070
H. pylori; metalloproteinase; gastritis
12.  Standardized ginger (Zingiber officinale) extract reduces bacterial load and suppresses acute and chronic inflammation in Mongolian gerbils infected with cagA+Helicobacter pylori 
Pharmaceutical biology  2009;47(1):92-98.
Previous investigations demonstrated that a standardized extract of ginger rhizome inhibited the growth of Helicobacter pylori in vitro with a minimum inhibitory concentration in the range 0.78 to 12.5 μg/mL. In the present work, the extract was tested in a rodent model of H. pylori-induced disease, the Mongolian gerbil, to examine the effects of the extract on both prevention and eradication of infection. The extract was administered to Mongolian gerbils at a daily dose of 100 mg/kg body weight in rations either 3 weeks prior to infection or 6 weeks post-infection. Treatment with the standardized ginger extract reduced H. pylori load as compared with controls and significantly (P<0.05) reduced both acute and chronic muscosal and submucosal inflammation, cryptitis, as well as epithelial cell degeneration and erosion induced by H. pylori. Importantly, the extract did not increase morbidity or mortality. Further investigations of the mechanism demonstrated that the ginger extract inhibited the activity of cyclooxygenase-2, with 50% inhibitory concentration (IC50) of 8.5 μg/mL in vitro, inhibited the nuclear factor-κB transcriptional response in kBZ Jurkat cells (human T lymphocytes) with an IC50 of 24.6 μg/mL, and significantly inhibited the release of interleukin (IL)-1β, IL-6, IL-8, and tumor necrosis factor-α from lipopolysaccharide-stimulated human peripheral blood mononuclear cells with IC50 values of 3.89, 7.7, 8.5, and 8.37 μg/mL, respectively. These results suggest ginger extracts may be useful for development as agents to reduce H. pylori-induced inflammation and as for gastric cancer chemoprevention.
PMCID: PMC2849670  PMID: 20376296
Antibacterial; chemoprevention; gastric cancer; ginger; gingerol; Helicobacter pylori; Mongolian gerbil; peptic ulcer disease; Zingiber officinale
13.  Human Gastric Mucins Differently Regulate Helicobacter pylori Proliferation, Gene Expression and Interactions with Host Cells 
PLoS ONE  2012;7(5):e36378.
Helicobacter pylori colonizes the mucus niche of the gastric mucosa and is a risk factor for gastritis, ulcers and cancer. The main components of the mucus layer are heavily glycosylated mucins, to which H. pylori can adhere. Mucin glycosylation differs between individuals and changes during disease. Here we have examined the H. pylori response to purified mucins from a range of tumor and normal human gastric tissue samples. Our results demonstrate that mucins from different individuals differ in how they modulate both proliferation and gene expression of H. pylori. The mucin effect on proliferation varied significantly between samples, and ranged from stimulatory to inhibitory, depending on the type of mucins and the ability of the mucins to bind to H. pylori. Tumor-derived mucins and mucins from the surface mucosa had potential to stimulate proliferation, while gland-derived mucins tended to inhibit proliferation and mucins from healthy uninfected individuals showed little effect. Artificial glycoconjugates containing H. pylori ligands also modulated H. pylori proliferation, albeit to a lesser degree than human mucins. Expression of genes important for the pathogenicity of H. pylori (babA, sabA, cagA, flaA and ureA) appeared co-regulated in response to mucins. The addition of mucins to co-cultures of H. pylori and gastric epithelial cells protected the viability of the cells and modulated the cytokine production in a manner that differed between individuals, was partially dependent of adhesion of H. pylori to the gastric cells, but also revealed that other mucin factors in addition to adhesion are important for H. pylori-induced host signaling. The combined data reveal host-specific effects on proliferation, gene expression and virulence of H. pylori due to the gastric mucin environment, demonstrating a dynamic interplay between the bacterium and its host.
PMCID: PMC3341350  PMID: 22563496
14.  Phosphatidylserine-dependent neuroprotective signaling promoted by docosahexaenoic acid 
Enrichment of polyunsaturated fatty acids, particularly docosahexaenoic acid (DHA, 22:6n–3), in the brain is known to be critical for optimal brain development and function. Mechanisms for DHA’s beneficial effects in the nervous system are not clearly understood at present. DHA is incorporated into the phospholipids in neuronal membranes, which in turn can influence not only the membrane chemical and physical properties but also the cell signaling involved in neuronal survival, proliferation and differentiation. Our studies have indicated that DHA supplementation promotes phosphatidylserine (PS) accumulation and inhibits neuronal cell death under challenged conditions, supporting a notion that DHA is an important neuroprotective agent. This article summarizes our findings on the DHA-mediated membrane-related signaling mechanisms that might explain some of the beneficial effects of DHA, particularly on neuronal survival.
PMCID: PMC3383770  PMID: 20207120
15.  DHA dietary supplementation enhances the effects of exercise on synaptic plasticity and cognition 
Neuroscience  2008;155(3):751-759.
Omega-3 fatty acids (i.e., docosahexaenoic acid; DHA), similar to exercise, improve cognitive function, promote neuroplasticity, and protect against neurological lesion. In this study, we investigated a possible synergistic action between DHA dietary supplementation and voluntary exercise on modulating synaptic plasticity and cognition. Rats received DHA dietary supplementation (1.25% DHA) with or without voluntary exercise for 12 days. We found that the DHA-enriched diet significantly increased spatial learning ability, and these effects were enhanced by exercise. The DHA-enriched diet increased levels of pro-BDNF and mature BDNF, whereas the additional application of exercise boosted the levels of both. Furthermore, the levels of the activated forms of CREB and synapsin I were incremented by the DHA-enriched diet with greater elevation by the concurrent application of exercise. While the DHA diet reduced hippocampal oxidized protein levels, a combination of a DHA diet and exercise resulted in a greater reduction rate. The levels of activated forms of hippocampal Akt and CaMKII were increased by the DHA-enriched diet, and with even greater elevation by a combination of diet and exercise. Akt and CaMKII signaling are crucial step by which BDNF exerts its action on synaptic plasticity and learning and memory. These results indicate that the DHA diet enhance the effects of exercise on cognition and BDNF-related synaptic plasticity, a capacity that may be used to promote mental health and reduce risk of neurological disorders.
PMCID: PMC3208643  PMID: 18620024
DHA; exercise; BDNF; omega-3 fatty acids; cognition
16.  Effects of n-3 fatty acids during neoplastic progression and comparison of in vitro and in vivo sensitivity of two human tumour cell lines. 
British Journal of Cancer  1995;71(4):691-696.
Several studies have shown that dietary lipid exerts an effect on carcinogenesis. We report here that progression to malignancy in vitro is associated with changes in the response to fatty acids (FAs). Tumorigenic (THKE) cells were more sensitive to the n-3 FAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) than immortalised (IHKE) cells. The growth of THKE cells was inhibited 25% more than the growth of IHKE cells at 80 microM EPA (P < 0.01) and 35% more at 40 microM DHA (P < 0.001). Furthermore, the results indicate that there is a wide cell type variation in the response to FAs. We found that the in vitro inhibition by FAs correlated with the reduction in the growth rate of the tumour in nude mice fed K85 (55% EPA and 30% DHA). A significant difference in tumour latency was observed for the A427 cell tumour groups (10 days, P < 0.05). Tumours in the animals fed n-3 FA exhibited significantly higher levels of EPA and DHA; the level of arachidonic acid (ARA) was significantly lower in THKE tumours and the level of linoleic acid (LA) was significantly lower in A427 tumours than in controls fed corn oil. The higher sensitivity of the A427 cell line was not explained by higher uptake of EPA/DHA.
PMCID: PMC2033729  PMID: 7710930
17.  Peroxidation of n-3 Polyunsaturated Fatty Acids Inhibits the Induction of iNOS Gene Expression in Proinflammatory Cytokine-Stimulated Hepatocytes 
Eicosapentaenoic acid and docosahexaenoic acid (EPA/DHA), n-3 polyunsaturated fatty acids (PUFAs), have a variety of biological activities including anti-inflammatory and anticancer effects. We hypothesized that their peroxidized products contributed in part to anti-inflammatory effects. In the liver, the production of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) has been implicated as one of the factors in hepatic inflammation and injury. We examined whether the peroxidation of EPA/DHA influences the induction of iNOS and NO production in proinflammatory cytokine-stimulated cultured hepatocytes, which is in vitro liver inflammation model. Peroxidized EPA/DHA inhibited the induction of iNOS and NO production in parallel with the increased levels of their peroxidation, whereas unoxidized EPA/DHA had no effects at all. Peroxidized EPA/DHA reduced the activation of transcription factor, NF-κB, and the expression of the iNOS antisense transcript, which are involved in iNOS promoter transactivation (mRNA synthesis) and its mRNA stabilization, respectively. These findings demonstrated that peroxidized products of EPA/DHA suppressed the induction of iNOS gene expression through both of the transcriptional and posttranscriptional steps, leading to the prevention of hepatic inflammation.
PMCID: PMC3136170  PMID: 21773019
18.  Immune Evasion by Helicobacter pylori is Mediated by Induction of Macrophage Arginase II1 
Helicobacter pylori infection persists for the life of the host due to the failure of the immune response to eradicate the bacterium. Determining how H. pylori escapes the immune response in its gastric niche is clinically important. We have demonstrated in vitro that macrophage NO production can kill H. pylori, but induction of macrophage arginase II (Arg2) inhibits inducible NO synthase (iNOS) translation, causes apoptosis, and restricts bacterial killing. We now determined if Arg2 impairs host defense in vivo, using a chronic H. pylori infection model. In C57BL/6 mice, expression of Arg2, but not arginase I (Arg1), was abundant and localized to gastric macrophages. Arg2−/− mice had increased histologic gastritis and decreased bacterial colonization compared to wild-type (WT) mice. Increased gastritis scores correlated with decreased colonization in individual Arg2−/− mice, but not WT mice. When mice infected with H. pylori were compared, Arg2−/− mice had more gastric macrophages, more of these cells were iNOS+, and these cells expressed higher levels of iNOS protein, as determined by flow cytometry and immunofluorescence microscopy. There was enhanced nitrotyrosine staining in infected Arg2−/− versus WT mice, indicating increased NO generation. Infected Arg2−/− mice exhibited decreased macrophage apoptosis, as well as enhanced IFN-γ, IL-17a, and IL-12p40 expression, and reduced IL-10 levels consistent with a more vigorous Th1/Th17 response. These studies demonstrate that Arg2 contributes to the immune evasion of H. pylori by limiting macrophage iNOS protein expression and NO production, mediating macrophage apoptosis, and restraining pro-inflammatory cytokine responses.
PMCID: PMC3069806  PMID: 21296975
19.  The safety and efficacy of oral docosahexaenoic acid supplementation for the treatment of primary sclerosing cholangitis – a pilot study 
Primary sclerosing cholangitis (PSC) is characterised by progressive inflammatory and fibrotic destruction of the biliary ducts. There are no effective medical therapies and presently high dose ursodeoxycholic acid is no longer recommended due to significant adverse events in a recent clinical trial. Cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction is associated with PSC in both children and adults. Since CFTR dysfunction leads to altered fatty acid metabolism, specifically reduced docosahexaenoic acid (DHA), we hypothesised that DHA supplementation might be an effective therapy for patients with PSC.
To determine the safety and efficacy of oral DHA supplementation for the treatment of PSC.
We conducted a 12 month open-label pilot study to evaluate safety of oral DHA and its effects on serum alkaline phosphatase as a primary outcome measure in 23 patients with PSC. DHA was administered orally at 800 mg twice per day. Secondary outcomes included changes in other liver function tests and fibrosis biomarkers.
A 1.7-fold increase in serum DHA levels was observed with supplementation. The mean alkaline phosphatase level (±S.E.) at baseline was 357.8 ± 37.1 IU compared to 297.1 ± 23.7 IU (P < 0.05) after 12 months of treatment. There were no changes in other liver function tests and fibrosis biomarkers. No adverse events were reported.
Oral DHA supplementation is associated with an increase in serum DHA levels and a significant decline in alkaline phosphatase levels in patients with PSC. These data support the need for a rigorous trial of DHA therapy in PSC.
PMCID: PMC3715379  PMID: 22129201
20.  Therapeutic Vaccination against Helicobacter pylori in the Beagle Dog Experimental Model: Safety, Immunogenicity, and Efficacy  
Infection and Immunity  2004;72(6):3252-3259.
Helicobacter pylori is a gram-negative bacterium that colonizes the human gastric mucosa causing gastritis and peptic ulcer and increasing the risk of gastric cancer. The efficacy of current antibiotic-based therapies can be limited by problems of patient compliance and increasing antibiotic resistance; the vaccine approach can overcome these limits. The present study describes the therapeutic vaccination of experimentally H. pylori-infected beagle dogs, an animal model that reproduces several aspects of the human infection with H. pylori. The vaccine consisted of three recombinant H. pylori antigens, CagA, VacA, and NAP, formulated at different doses (10, 25, or 50 μg each) with alum and administered intramuscularly either weekly or monthly. No adverse effects were observed after vaccination and a good immunoglobulin G response was generated against each of the three antigens. Bacterial colonization and gastritis were decreased after the completion of the vaccination cycle, especially in the case of the monthly immunization schedule. In conclusion, therapeutic vaccination in the beagle dog model was safe and immunogenic and was able to limit H. pylori colonization and the related gastric pathology.
PMCID: PMC415659  PMID: 15155627
21.  The Effect of varying ratios of docosahexaenoic Acid and arachidonic acid in the prevention and reversal of biochemical essential fatty acid deficiency in a murine model 
Essential fatty acids (EFA) are necessary for growth, development, and biological function, and must be acquired through the diet. While linoleic acid (LA) and alpha-linolenic acid (ALA) have been considered the true EFAs, we previously demonstrated that docosahexaenoic acid (DHA) and arachidonic acid (AA) taken together as the sole source of dietary fatty acids can prevent biochemical essential fatty acid deficiency (EFAD). This study evaluates the effect of varying dietary ratios of DHA:AA in the prevention and reversal of biochemical EFAD in a murine model.
Using a murine model of EFAD, we provided mice with 2.1% of daily caloric intake in varying DHA:AA ratios (1:1, 5:1, 10:1, 20:1, 200:1, 100:0) for 19 days in association with a liquid high-carbohydrate fat-free diet to evaluate the effect on fatty acid profiles. In a second experiment, we evaluated the provision of varying DHA:AA ratios (20:1, 200:1, 100:0) on the reversal of biochemical EFAD.
Mice provided with DHA and AA had no evidence of biochemical EFAD, regardless of the ratio (1:1, 5:1, 10:1, 20:1, 200:1, 100:0) administered. Biochemical EFAD was reversed with DHA:AA ratios of 20:1, 200:1, and 100:0 following 3 and 5 weeks of dietary provision, although the 20:1 ratio was most effective in the reversal and stabilization of the triene:tetraene ratio.
Provision of DHA and AA, at 2.1% of daily caloric intake in varying ratios can prevent biochemical evidence of EFAD and hepatic steatosis over the short-term, with a ratio of 20:1 DHA:AA most effectively reversing EFAD.
PMCID: PMC3608741  PMID: 23151438
omega-3; polyunsaturated fatty acid; triene:tetraene ratio; dietary lipid; mouse
22.  Chemoprevention of DMBA-induced mammary carcinogenesis in rats by low-dose EPA and DHA. 
British Journal of Cancer  1997;75(3):348-353.
We investigated the effects of low-dose eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the incidence and growth of 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinoma in rats fed a high-fat (HF) diet. We also examined the effects of these treatments on the fatty acid composition of tumour and serum. Tumour incidence was significantly decreased by the administration of low-dose EPA and DHA, whereas their inhibitory effects on tumour growth did not reach significance. Serum arachidonic acid (AA) level was decreased by the administration of low-dose EPA and tended to be decreased by the administration of low-dose DHA, whereas tumour AA levels were not changed. The administration of low-dose EPA and DHA may be useful for inhibiting the incidence of breast cancer.
PMCID: PMC2063366  PMID: 9020478
23.  Effect of physiological concentrations of vitamin C on gastric cancer cells and Helicobacter pylori 
Gut  2002;50(2):165-169.
Background: Gastric juice vitamin C may be protective against gastric carcinogenesis but concentrations are significantly reduced by Helicobacter pylori infection. We investigated the in vitro effects of vitamin C at concentrations comparable with those found in gastric juice on gastric cancer cells and H pylori.
Methods: Gastric cancer cell lines and various H pylori strains were treated with l-ascorbic acid for up to 72 hours. Cell viability, and protein and DNA synthesis were determined. Flow cytometry was used for assessment of H pylori adherence, cell cycle distribution, and apoptosis. H pylori growth and its haemagglutination activity were determined using viability count and microtitration assay.
Results: Vitamin C induced a significant dose dependent growth inhibition of gastric AGS and MKN45 cells but this effect was significantly reduced at levels similar to those in gastric juice of H pylori infected patients (<50 μM). Although vitamin C had no obvious effect on H pylori growth, haemagglutination activity, or adherence ability to gastric AGS cells compared with untreated controls, it significantly enhanced H pylori associated apoptosis and induced cell cycle arrest in these cells.
Conclusion: Vitamin C may inhibit gastric cancer cell growth and alter H pylori induced cell cycle events at concentrations comparable with those in gastric juice, but has no effect on H pylori growth or pathogenicity. However, the inhibitory effect on gastric cancer cells was lost at vitamin C concentrations found in patients with H pylori infection.
PMCID: PMC1773094  PMID: 11788554
Helicobacter pylori; vitamin C; gastric cancer
24.  Mechanism of Growth Inhibition of Human Cancer Cells by Conjugated Eicosapentaenoic Acid, an Inhibitor of DNA Polymerase and Topoisomerase 
DNA topoisomerases (topos) and DNA polymerases (pols) are involved in many aspects of DNA metabolism such as replication reactions. We found that long chain unsaturated fatty acids such as polyunsaturated fatty acids (PUFA) (i.e., eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) inhibited the activities of eukaryotic pols and topos in vitro, and the inhibitory effect of conjugated fatty acids converted from EPA and DHA (cEPA and cDHA) on pols and topos was stronger than that of normal EPA and DHA. cEPA and cDHA did not affect the activities of plant and prokaryotic pols or other DNA metabolic enzymes tested. cEPA was a stronger inhibitor than cDHA with IC50 values for mammalian pols and human topos of 11.0 – 31.8 and 0.5 – 2.5 μM, respectively. cEPA inhibited the proliferation of two human leukemia cell lines, NALM-6, which is a p53-wild type, and HL-60, which is a p53-null mutant, and the inhibitory effect was stronger than that of normal EPA. In both cell lines, cEPA arrested in the G1 phase, and increased cyclin E protein levels, indicating that it blocks the primary step of in vivo DNA replication by inhibiting the activity of replicative pols rather than topos. DNA replication-related proteins, such as RPA70, ATR and phosphorylated-Chk1/2, were increased by cEPA treatment in the cell lines, suggesting that cEPA led to DNA replication fork stress inhibiting the activities of pols and topos, and the ATR-dependent DNA damage response pathway could respond to the inhibitor of DNA replication. The compound induced cell apoptosis through both p53-dependent and p53-independent pathways in cell lines NALM-6 and HL-60, respectively. These results suggested the therapeutic potential of conjugated PUFA, such as cEPA, as a leading anti-cancer compound that inhibited pols and topos activities.
PMCID: PMC3871801
conjugated eicosapentaenoic acid (cEPA); DNA polymerase; DNA topoisomerase; enzyme inhibitor; DNA replication; cell proliferation; cell cycle arrest; p53; apoptosis
25.  Short term effects of different omega-3 fatty acid formulation on lipid metabolism in mice fed high or low fat diet 
Bioactivities of Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA) depend on their chemical forms. The present study was to investigate short term effects of triglyceride (TG), ethyl ester (EE), free fatty acid (FFA) and phospholipid (PL) forms of omega-3 fatty acid (FA) on lipid metabolism in mice, fed high fat or low fat diet.
Male Balb/c mice were fed with 0.7% different Omega-3 fatty acid formulation: DHA bound free fatty acid (DHA-FFA), DHA bound triglyceride (DHA-TG), DHA bound ethyl ester (DHA-EE) and DHA bound phospholipid (DHA-PL) for 1 week, with dietary fat levels at 5% and 22.5%. Serum and hepatic lipid concentrations were analyzed, as well as the fatty acid composition of liver and brain.
At low fat level, serum total cholesterol (TC) level in mice fed diets with DHA-FFA, DHA-EE and DHA-PL were significantly lower than that in the control group (P < 0.05). Hepatic TG level decreased significantly in mice fed diets with DHA-TG (P < 0.05), DHA-EE (P < 0.05) and DHA-PL (P < 0.05), while TC level in liver was significantly lower in mice fed diets with TG and EE compared with the control group (P < 0.05). At high fat level, mice fed diets with DHA-EE and DHA-PL had significantly lower hepatic TC level compared with the control diet (P < 0.05). Hepatic PL concentration experienced a significant increase in mice fed the diet with PL at high fat level (P < 0.05). Furthermore, both at low and high fat levels, hepatic DHA level significantly increased and AA level significantly decreased in all forms of DHA groups (P < 0.05), compared to control groups at two different fat levels, respectively. Additionally, cerebral DHA level in mice fed diets with DHA-FFA, DHA-EE and DHA-PL significantly increased compared with the control at high fat level (P < 0.05), but no significant differences were observed among dietary treatments for mice fed diets with low fat level.
The present study suggested that not only total dietary fat content but also the molecular forms of omega-3 fatty acids contributed to lipid metabolism in mice. DHA-PL showed effective bioactivity in decreasing hepatic and serum TC, TG levels and increasing omega-3 concentration in liver and brain.
PMCID: PMC3393618  PMID: 22676394
Omega-3 fatty acid; DHA; EPA; Lipid metabolism; Triglycerides; Ethyl ester; Phospholipids

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