Changes of the mucosal n3 and n6 fatty acid status occur early in the colorectal adenoma-carcinoma sequence

Long-chain polyunsaturated fatty acids influence colorectal cancer progression via the interactions between the intestinal microflora and the macrophages

The metabolism of long-chain polyunsaturated fatty acids (LCPUFAs) is closely associated with the risk and progression of colorectal cancer (CRC). This paper aims to investigate the role of LCPUFA in the crosstalk between intestinal microflora and macrophages, as well as the effects of these three parties on the progression of CRC. The metabolism and function of LCPUFA play important roles in regulating the composition of the human gut microflora and participating in the regulation of inflammation, ultimately affecting macrophage function and polarization, which is crucial in the tumor microenvironment. The effects of LCPUFA on cellular interactions between the two species can ultimately influence the progression of CRC. In this review, we explore the molecular mechanisms and clinical applications of LCPUFA in the interactions between intestinal microflora and intestinal macrophages, as well as its significance for CRC progression. Furthermore, we reveal the role of LCPUFA in the construction of the CRC microenvironment and explore the key nodes of the interactions between intestinal flora and intestinal macrophages in the environment. It provides potential targets for the metabolic diagnosis and treatment of CRC.

Association between dietary intake of fatty acids and colorectal cancer, a case-control study

Background

The association of dietary fat and colorectal cancer (CRC) was frequently reported. However, few studies assessed the effects of different types of dietary fats on CRC. This study aimed to investigate the association between intakes of different types of dietary fatty acids with colorectal cancer risk.

Methods

This case-control study was conducted on 480 participants including 160 CRC cases and 320 healthy controls in Firoozgar Hospital, Tehran, Iran. The intake of dietary fatty acids of the participants was assessed using a semi quantitative food frequency questionnaire (FFQ).

Results

The mean intake of cholesterol (273.07 ± 53.63 vs. 254.17 ± 61.12, P = 0.001), polyunsaturated fatty acids (PUFA) (16.54 ± 4.20 vs. 15.41 ± 4.44, P = 0.012), and calorie (2,568.76 ± 404.48 vs. 2,493.38 ± 176.03, P = 0.006) was higher and the mean intake of oleic acid (5.59 ± 3.17 vs. 8.21 ± 5.46) and linoleic acid (6.03 ± 3.44 vs. 7.02 ± 4.08, P = 0.01) was lower in the case group compared to the control group. An inverse association was found between colorectal cancer (CRC) and dietary intake of oleic acid (OR: 0.85, CI 95% 0.80–0.90, P = 0.001), linoleic acid (OR: 0.85, CI 95% 0.78–0.93, P = 0.001), and α-linolenic acid (OR: 0.75, CI 95% 0.57–0.98, P = 0.04). The association remained significant after adjusting for age and sex, sleep, smoking, and alcohol consumption, and BMI.

Conclusions

The results of this study support a protective effect of oleic acid, linoleic acid, and α-linolenic acid against CRC. Further longitudinal studies are warranted to confirm these results.

A serum metabolomics study based on LC-MS: Chemosensitization effects of Rauvolfia vomitoria Afzel. combined with 5- fluorouracil on colorectal cancer mice

Colorectal cancer (CRC) is one of the malignant tumors with high incidence, and is mainly treated by chemotherapy at present. However, during CRC treatment, long-term use of traditional chemotherapeutic drugs will reduce the sensitivity of chemotherapy. Our previous studies have shown that Rauvolfia vomitoria total alkaloids (RVA) played an important role in 5-fluorouracil (5-FU) chemosensitization in CRC therapy, but its intervention mechanism has not been clarified completely in the metabolic level. Therefore, in this study, LC-MS based metabolomics was employed to explore the mechanism of 5-FU chemosensitization in CRC induced by the combination of RVA and conventional chemotherapeutic with 5-FU. The results showed that the final tumor weight of the high-dose combined group was significantly different from that of the 5-FU alone group. To evaluate the chemosensitization effects of RVA, serum samples collected from six groups (six mice in each group) with different administration methods were analyzed by HPLC-Q-Exactive Orbitrap/MS. After multivariate statistical analysis and metabolites identification, 25 different metabolites were identified between the 5-FU treatment group and combined high-dose treatment group, among which lipid and fatty acid metabolism pathways were mostly affected. These results suggest that RVA may sensitize traditional chemotherapeutic drug 5-FU and exert anti-tumor activity through influencing lipid metabolism and cell energy metabolism. Metabolomics provided a new insight into estimate of the therapeutic effect and dissection of the potential mechanisms of traditional Chinese medicine in treating colorectal cancer.

Metabolomics Analysis of Laparoscopic Surgery Combined with Wuda Granule to Promote Rapid Recovery of Patients with Colorectal Cancer Using UPLC/Q-TOF-MS/MS

Surgery is the primary curative treatment for patients with nonmetastasized colorectal cancer (CRC). Rate of complications, morbidity, mortality, and overall survival of patients with CRC are factors associated with speed of recovery following surgery. Wuda granule (WD) is a traditional Chinese medicine (TCM) prescription used to promote rapid recovery after surgery. However, the specific mechanism of action of WD has not been characterized. Our study included 60 patients with clear histopathological evidence of colon or rectal cancer who underwent CRC laparoscopic surgery and 30 healthy individuals. Serum biochemistry and clinical evaluation of gastrointestinal function showed that WD could improve the nutritional status and gastrointestinal function and reduce the level of inflammation of patients with CRC following laparoscopic surgery. In addition, we used UPLC/Q-TOF-MS/MS-based metabolomics analysis to determine the mechanism of WD-related rapid recovery following laparoscopic surgery in patients with CRC. Twenty metabolites associated with arachidonic acid, alanine, aspartate and glutamate, α-linolenic acid, pyruvate, histidine, and glycerophospholipids were identified. The results suggested that the therapeutic mechanism of laparoscopic surgery combined with WD may be related to regulation of nutritional status, inflammation, immune function, energy, and gastrointestinal function in patients with CRC. This study also highlighted the ability of TCM compounds to interact with multiple targets to induce synergistic effects. This study may result in further studies of WD as a therapeutic agent to promote recovery following surgical resection of CRC tumors.

Dietary nutrient patterns and the risk of colorectal cancer and colorectal adenomas: a case-control study

Although the association between food patterns and the risk of colorectal cancer (CRC) and colorectal adenomas (CRA) has been explored previously, a distinct paucity of studies has evaluated the association of nutrient pattern and the risk of CRC and CRA as precursors of CRC. Thus, the purpose of this case-control study was to investigate nutrient patterns and their relationship with CRC and CRA in Iran. Two hundred forty hospital control, 129 newly diagnosed CRC and 130 newly diagnosed CRA patients were asked about their dietary intakes using validated questionnaires. To define the major nutrient patterns, principal component analysis was applied based on preselected nutrients, and four explainable nutrient patterns were obtained: Factor 1 (mixed), factor 2 (the antioxidant), factor 3 (dairy) and factor 4 (the high fat). Logistic regression was used to determine odds ratios (OR) with 95% confidence interval (CI) of CRC and CRA according to categories of nutrient patterns. After adjusting for confounders, factor 2 was significantly associated with lower risk for the CRC and CRA in the second category compared with the first, respectively (OR = 0.20, 95% CI: 0.12-0.34, OR = 0.34, 95% CI: 0.21-0.56). Participants in the highest category of factor 4 showed an increase in the risk of CRC and CRA, respectively, than those in the low category, in both crude and multivariate analysis (OR = 1.77, 95% CI: 1.57-2.95, OR = 1.85, 95% CI: 1.13-3.02). Among derived nutrient patterns, 'the antioxidant pattern' was inversely associated with CRC/CRA, whilst 'high fat pattern' showed a direct association with these diseases.

Phospholipid profiling enables to discriminate tumor- and non-tumor-derived human colon epithelial cells: Phospholipidome similarities and differences in colon cancer cell lines and in patient-derived cell samples

Identification of changes of phospholipid (PL) composition occurring during colorectal cancer (CRC) development may help us to better understand their roles in CRC cells. Here, we used LC-MS/MS-based PL profiling of cell lines derived from normal colon mucosa, or isolated at distinct stages of CRC development, in order to study alterations of PL species potentially linked with cell transformation. We found that a detailed evaluation of phosphatidylinositol (PI) and phosphatidylserine (PS) classes allowed us to cluster the studied epithelial cell lines according to their origin: i) cells originally derived from normal colon tissue (NCM460, FHC); ii) cell lines derived from colon adenoma or less advanced differentiating adenocarcinoma cells (AA/C1, HT-29); or, iii) cells obtained by in vitro transformation of adenoma cells and advanced colon adenocarcinoma cells (HCT-116, AA/C1/SB10, SW480, SW620). Although we tentatively identified several PS and PI species contributing to cell line clustering, full PI and PS profiles appeared to be a key to the successful cell line discrimination. In parallel, we compared PL composition of primary epithelial (EpCAM-positive) cells, isolated from tumor and adjacent non-tumor tissues of colon cancer patients, with PL profiles of cell lines derived from normal colon mucosa (NCM460) and from colon adenocarcinoma (HCT-116, SW480) cells, respectively. In general, higher total levels of all PL classes were observed in tumor cells. The overall PL profiles of the cell lines, when compared with the respective patient-derived cells, exhibited similarities. Nevertheless, there were also some notable differences in levels of individual PL species. This indicated that epithelial cell lines, derived either from normal colon tissue or from CRC cells, could be employed as models for functional lipidomic analyses of colon cells, albeit with some caution. The biological significance of the observed PL deregulation, or their potential links with specific CRC stages, deserve further investigation.

Vitamin D, linoleic acid, arachidonic acid and COX-2 in colorectal cancer patients in relation to disease stage, tumour localisation and disease progression

BACKGROUND AND STUDY AIMS

Evidence shows that vitamin D and cyclooxygenase type 2 (COX-2) might play role in aetiology/progression of cancer. It is suggested that antitumour effect of vitamin D depends on vitamin D-receptor (VDR) expression. Aim of the study was to determine vitamin D and polyunsaturated fatty acids in colorectal cancer patients.

PATIENTS AND METHODS

A total of 39 patients with colorectal cancer (mean ± SD age: 65.5 ± 6.8 years) and 25 controls (mean ± SD age: 51.0 ± 6.9 years) were studied. 25-hydroxycholecalciferol-25(OH)D₃ in serum was quantitatively determined by high-performance liquid chromatography (HPLC). Levels of linoleic acid (LA) and arachidonic acid (AA) of serum phospholipids were measured by gas-chromatography (GC). Expression of VDR and COX-2 in normal colonic mucosa and tumour tissue was measured by real time polymerase chain reaction (RT-PCR).

RESULTS

The mean value of 25(OH)D₃ was significantly lower in the colorectal cancer patients with early stages of the disease and in patients with tumour confined to the rectum compared to control group (p < 0.02, p < 0.03, respectively). The higher concentration of AA (patients with early stages of the disease) and lower concentration of LA (patients with the advanced stages of the disease) was noticed compared to the control group. For the patients with the early stages of the disease the higher mean fold change of mRNA VDR and the lower mean fold change of mRNA COX-2 was noticed (p < 0.03, p < 0.02, respectively).

CONCLUSION

The assessment of vitamin D status in patients with colorectal cancer should include measurement of mRNA VDR expression in tumour tissue.

Serum metabolite profiling of familial adenomatous polyposis using ultra performance liquid chromatography and tandem mass spectrometry

Familial adenomatous polyposis (FAP) is an autosomal dominantly inherited intestinal polyposis syndrome accounting for about 1% of colorectal cancers (CRC). Despite increasing researches on the molecular pathogenesis of CRC, we are still unclear about metabolic pathways and alterations probably involved in the development of CRC. To obtain new insights into the mechanisms underlying APC mutation and to elucidate the mechanisms of CRC development, we performed to identify the potential metabolites in FAP based on metabolomic strategy. Serum metabolites from FAP patients (n = 30) and healthy individuals (n = 34) were detected and qualified using Ultra Performance Liquid Chromatography and Tandem Mass Spectrometry (UPLC- MS/MS). 118 metabolites were identified with statistical tests of orthogonal partial least-squares-discriminant analysis (OPLS-DA), with the conditions of variable importance in projection (VIP) >1, p < 0.05 using the Mann-Whitney U test, and fold change (FC) ≥2 or ≤0.5. OPLS-DA model was useful for distinguishing FAP patients from healthy controls. Unique metabolic signatures were pooled in FAP patients covering tricarboxylic acid (TCA) cycle, amino acids metabolism, vitamin D, fatty acids metabolism, and bile acids (BAs) metabolism. Our results demonstrated that metabolites alterations in FAP can be helpful for further analysis of metabonomics induced by APC mutation, and these alterations might be involved in the progress of intestinal carcinogenesis.

Modulation of plasma and urine metabolome in colorectal cancer survivors consuming rice bran

Rice bran has bioactive phytochemicals with cancer protective actions that involve metabolism by the host and the gut microbiome. Globally, colorectal cancer (CRC) is the third leading cause of cancer-related death and the increased incidence is largely attributed to poor dietary patterns, including low daily fiber intake. A dietary intervention trial was performed to investigate the impact of rice bran consumption on the plasma and urine metabolome of CRC survivors. Nineteen CRC survivors participated in a randomized-controlled trial that included consumption of heat-stabilized rice bran (30 g/day) or a control diet without rice bran for 4 weeks. A fasting plasma and first void of the morning urine sample were analyzed by non-targeted metabolomics using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). After 4 weeks of either rice bran or control diets, 12 plasma and 16 urine metabolites were significantly different between the groups (p≤0.05). Rice bran intake increased relative abundance of plasma mannose (1.373-fold) and beta-citrylglutamate (BCG) (1.593-fold), as well as increased urine N-formylphenylalanine (2.191-fold) and dehydroisoandrosterone sulfate (DHEA-S) (4.488-fold). Diet affected metabolites, such as benzoate, mannose, eicosapentaenoate (20:5n3) (EPA), and N-formylphenylalanine have been previously reported for cancer protection and were identified from the rice bran food metabolome. Nutritional metabolome changes following increased consumption of whole grains such as rice bran warrants continued investigation for colon cancer control and prevention attributes as dietary biomarkers for positive effects are needed to reduce high risk for colorectal cancer recurrence.

Long-chain ω-6 plasma phospholipid polyunsaturated fatty acids and association with colon adenomas in adult men: a cross-sectional study

Dietary lipid intake can be associated with an increased risk for colorectal cancer depending on its composition. Carcinogenesis alters lipid metabolism to facilitate cell growth and survival. For instance, metabolites of polyunsaturated fatty acids (PUFAs) are associated with increasing colon cell proliferation. Moreover, precancerous colon lesions (i.e. adenomas) increase the risk for colorectal cancer. In this study, we investigated associations between plasma PUFAs and the number of colon polyps and polyp type (i.e. hyperplastic and adenoma). Healthy male participants (n=126) of 48-65 years of age were recruited before a routine colonoscopy screening. Plasma phospholipid (PPL) PUFAs were isolated by means of solid phase extraction and methylated. Fatty acid methyl esters were analyzed using gas chromatography. Factor analysis was used to cluster PUFAs into groups, and then generated factors and individual PUFAs were analyzed using polytomous logistic regression. In our age-adjusted and smoking-adjusted polytomous logistic regression, for each unit increase in PPL docosatetraenoic acid (DTA), individuals were 1.43 (1.00-2.06) and 1.33 (0.99-1.80) times more likely to have hyperplastic polyps and adenomas rather than no polyps, respectively. In our factor analysis, high PPL ω-6 PUFA and trans-fatty acid loading scores were associated with increased odds of adenoma presence rather than no polyps. Increases in long-chain PPL ω-6 PUFAs are associated with an increased risk for adenomas. As relative levels of DTA increase in PPLs, individuals had increased odds of having hyperplastic polyps and adenomas. Elevated conversion of ω-6 PUFAs to longer-chain ω-6s such as DTA may indicate altered PUFA metabolism at the tissue level.

Composition and Concentration of Serum Fatty Acids of Phospholipids Depend on Tumour Location and Disease Progression in Colorectal Patients

BACKGROUND

Polyunsaturated fatty acids (PUFAs) play a role in the development/progression of colon cancer. The aim of the study was to assess the relation between serum phospholipids PUFAs, colorectal tumour localization and disease progression.

METHODS

A total of 67 patients (18 with proximal colon, 17 with distal colon and 32 with rectal tumour localization) as well as 16 controls were studied. One year after surgery, 33 patients had disease progression. Serum levels of C16:1(n-7), C18:1(n-9), C18:3(n-3), C20:5(n-3), C22:6(n- 3), C18:2(n-6), C20:2(n-6), C20:4(n-6) fatty acids of se - rum phospholipids were quantitatively measured before surgery by gas-chromatography.

RESULTS

Significantly higher mean value of C18:2, as compared to control, has been noted only for patients with proximal (p<0.05) and distal tumour (p<0.03) localization. The lower mean level of C20:5 and unsaturation index (UI) were observed in colorectal cancer patients regardless the tumour localization, but the statistical difference was noted only for patients with proximal tumours (p<0.05, p<0.03). In patients with proximal tumours, significantly lower mean level of C20:4 and UI were noted in patients with disease progression, as compared to patients with proximal tumours without disease progression (p<0.05).

CONCLUSION

The evaluation of PUFAs as a risk/prognostic factor in colorectal cancer patients should take into account tumour localization as a dependent variable.

Biospecimen long-chain N-3 PUFA and risk of colorectal cancer: a meta-analysis of data from 60,627 individuals

Background

Several prospective cohort and case-control studies reported the inconsistent association between biospecimen composition of C20 and C22 long-chain (LC) n-3 polyunsaturated fatty acid (PUFA) and colorectal cancer (CRC) risk. The aim of the present study was to investigate the association of biospecimen LC n-3 PUFA with CRC risk based on prospective cohort and case-control studies.

Methods and Results

Cochrane Library, PubMed, and EMBASE database were searched up to February 2014 for eligible studies. Risk ratios (RRs) or odds ratios (ORs) from prospective and case-control studies were combined using a random-effects model in the highest vs. lowest categorical analysis. Nonlinear dose-response relationships were assessed using restricted cubic spline regression models. Difference in tissue composition of LC n-3 PUFA between cases and noncases was analyzed as standardized mean difference (SMD). Three prospective cohort studies and 8 case-control studies were included in the present study, comprising 60,627 participants (1,499 CRC cases and 59,128 noncases). Higher biospecimen LC n-3 PUFA was significantly associated with a lower risk of CRC in case-control (pooled OR: 0.76; 95% CI: 0.59, 0.97; I² = 10.00%) and prospective cohort studies (pooled RR: 0.70; 95% CI: 0.55, 0.88; I² = 0.00%), respectively. A significant dose-response association was found of biospecimen C20:5n-3 (P for nonlinearity  = 0.02) and C22:6n-3 (P for trend  = 0.01) with CRC risk, respectively. Subjects without CRC have significantly higher biospecimen compositions of C20:5n-3 (SMD: 0.27; 95%: 0.13, 0.41), C22:6n-3 (SMD: 0.23; 95%: 0.11, 0.34) and total LC n-3 PUFA (SMD: 0.22; 95% CI: 0.07, 0.37) compared with those with CRC.

Conclusions

The present evidence suggests human tissue compositions of LC n-3 PUFA may be an independent predictive factor for CRC risk, especially C20:5n-3 and C22:6n-3. This needs to be confirmed with more large-scale prospective cohort studies.

Is the omega-3 index a valid marker of intestinal membrane phospholipid EPA+DHA content?

Despite numerous studies investigating n-3 long chain polyunsaturated fatty acid (LCPUFA) supplementation and inflammatory bowel diseases (IBD), the extent to which dietary n-3 LCPUFAs incorporate in gastrointestinal (GI) tissues and correlate with red blood cell (RBC) n-3 LCPUFA content is unknown. In this study, mice were fed three diets with increasing percent of energy (%en) derived from eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA). Dietary levels reflected recommended intakes of fish/fish oil by the American Heart Association. We analyzed the FA composition of phospholipids extracted from RBCs, plasma, and GI tissues. We observed that the 0.1%en EPA+DHA diet was sufficient to significantly increase the omega-3 index (RBC EPA+DHA) after 5 week feeding. The baseline EPA levels were 0.2-0.6% across all tissues increasing to 1.6-4.3% in the highest EPA+DHA diet; these changes resulted in absolute increases of 1.4-3.9% EPA across tissues. The baseline DHA levels were 2.2-5.9% across all tissues increasing to 5.8-10.5% in the highest EPA+DHA diet; these changes resulted in absolute increases of 3.2-5.7% DHA across tissues. These increases in EPA and DHA across all tissues resulted in strong (r>0.91) and significant (P<0.001) linear correlations between the omega-3 index and plasma/GI tissue EPA+DHA content, suggesting that the omega-3 index reflects the relative amounts of EPA+DHA in GI tissues. These data demonstrate that the GI tissues are highly responsive to dietary LCPUFA supplementation and that the omega-3 index can serve as a valid biomarker for assessing dietary EPA+DHA incorporation into GI tissues.

Diets rich in n-6 PUFA induce intestinal microbial dysbiosis in aged mice

Controversies have emerged regarding the beneficial v. detrimental effects of dietary n-6 PUFA. The alteration of the intestinal microbiota, a phenomenon termed dysbiosis, occurs during several chronic inflammatory diseases, but has not been well studied in an aged population. With present ‘Western’ diets predominantly composed of n-6 PUFA, we hypothesised that PUFA-rich diets cause intestinal dysbiosis in an aged population. C57BL/6 mice (aged 2 years) were fed a high-fat (40% energy), isoenergetic and isonitrogenous diet composed of rapeseed oil, maize oil or maize oil supplemented with fish oil. We examined ileal microbiota using fluorescence in situ hybridisation and stained tissues by immunofluorescence for the presence of immune cells and oxidative stress. We observed that feeding high-fat diets rich in n-6 PUFA promoted bacterial overgrowth but depleted microbes from the Bacteroidetes and Firmicutes phyla. This corresponded with increased body mass and infiltration of macrophages and neutrophils. Fish oil supplementation (rich in long-chain n-3 PUFA like DHA and EPA) restored the microbiota and inflammatory cell infiltration and promoted regulatory T-cell recruitment. However, fish oil supplementation was associated with increased oxidative stress, evident by the increased presence of 4-hydroxynonenal, a product of lipid peroxidation. These results suggest that an n-6 PUFA-rich diet can cause dysbiosis and intestinal inflammation in aged mice. However, while fish oil supplementation on an n-6 PUFA diet reverses dysbiosis, the combination of n-6 and n-3 PUFA, like DHA/EPA, leads to increased oxidative stress, which could exacerbate gastrointestinal disorders in the elderly.

Fatty acids in habitual diet, plasma phospholipids, and tumour and normal colonic biopsies in young colorectal cancer patients

Fatty acid metabolism is altered in colorectal cancer (CRC). We aimed to investigate incorporation of dietary n-6 and n-3 polyunsaturated fatty acids (PUFAs) into plasma phospholipids (PLs), tumour tissue, and normal mucosa in young CRC patients. We also aimed to study differences in PUFA composition between tumour and normal mucosa, and PUFA status associated with cancer stage. Sixty-five CRC patients younger than 55 years were included in a multicenter study. We assessed dietary fatty acid composition by food-frequency questionnaire. Fatty acid composition in plasma PL (n = 65) and tumour and normal colonic biopsies (n = 32) were analysed by gas chromatography. We observed a significant correlation for docosahexaenoic acid (DHA) between dietary intake and concentration in plasma PL (weight%) (r = 0.42; P = 0.001), but not for any n-6 PUFA. Tissue concentrations of arachidonic acid, eicosapentaenoic acid, and DHA (weight%) were 1.7–2.5 times higher in tumour than normal mucosa (P ≤ 0.001). Concentrations of n-3 and n-6 PUFA in plasma PL and tissues were not related to Duke's stage, although patients with more severe cancer stage reported higher intake of n-3 PUFA. In conclusion, we found accumulation of the long-chained n-3 and n-6 PUFA in tumour tissue in young CRC patients.

Arachidonic acid and cancer risk: a systematic review of observational studies

Background

An n-6 essential fatty acid, arachidonic acid (ARA) is converted into prostaglandin E₂, which is involved in tumour extension. However, it is unclear whether dietary ARA intake leads to cancer in humans. We thus systematically evaluated available observational studies on the relationship between ARA exposure and the risk of colorectal, skin, breast, prostate, lung, and stomach cancers.

Methods

We searched the PubMed database for articles published up to May 17, 2010. 126 potentially relevant articles from the initial search and 49,670 bibliographies were scrutinised to identify eligible publications by using predefined inclusion criteria. A comprehensive literature search yielded 52 eligible articles, and their reporting quality and methodological quality was assessed. Information on the strength of the association between ARA exposure and cancer risk, the dose-response relationship, and methodological limitations was collected and evaluated with respect to consistency and study design.

Results

For colorectal, skin, breast, and prostate cancer, 17, 3, 18, and 16 studies, respectively, were identified. We could not obtain eligible reports for lung and stomach cancer. Studies used cohort (n = 4), nested case-control (n = 12), case-control (n = 26), and cross-sectional (n = 12) designs. The number of subjects (n = 15 - 88,795), ARA exposure assessment method (dietary intake or biomarker), cancer diagnosis and patient recruitment procedure (histological diagnosis, cancer registries, or self-reported information) varied among studies. The relationship between ARA exposure and colorectal cancer was inconsistent based on ARA exposure assessment methodology (dietary intake or biomarker). Conversely, there was no strong positive association or dose-response relationship for breast or prostate cancer. There were limited numbers of studies on skin cancer to draw any conclusions from the results.

Conclusions

The available epidemiologic evidence is weak because of the limited number of studies and their methodological limitations, but nonetheless, the results suggest that ARA exposure is not associated with increased breast and prostate cancer risk. Further evidence from well-designed observational studies is required to confirm or refute the association between ARA exposure and risk of cancer.

The Mediterranean diet: effects on proteins that mediate fatty acid metabolism in the colon

A Mediterranean diet appears to have health benefits in many domains of human health, mediated perhaps by its anti-inflammatory effects. Metabolism of fatty acids and subsequent eicosanoid production is a key mechanism by which a Mediterranean diet can exert anti-inflammatory effects. Both dietary fatty acids and fatty acid metabolism determine fatty acid availability for cyclooxygenase- and lipoxygenase-dependent production of eicosanoids, namely prostaglandins and leukotrienes. In dietary intervention studies and in observational studies of the Mediterranean diet, blood levels of fatty acids do reflect dietary intakes but are attenuated. Small differences in fatty acid levels, however, appear to be important, especially when exposures occur over long periods of time. This review summarizes how fat intakes from a Greek-style Mediterranean diet can be expected to affect fatty acid metabolizing proteins, with an emphasis on the metabolic pathways that lead to the formation of proinflammatory eicosanoids. The proteins involved in these pathways are ripe for investigation using proteomic approaches and may be targets for colon cancer prevention.

Nutrition modulation of gastrointestinal toxicity related to cancer chemotherapy: from preclinical findings to clinical strategy

Chemotherapy-induced gut toxicity is a major dose-limiting toxicity for many anticancer drugs. Gastrointestinal (GI) complications compromise the efficacy of chemotherapy, promote overall malnutrition, aggravate cancer cachexia, and may contribute to worsened prognosis. The GI tract is an attractive target for nutrition modulation, owing to its direct exposure to the diet, participation in uptake and metabolism of nutrients, high rate of cell turnover, and plasticity to nutrition stimuli. Glutamine, ω-3 polyunsaturated fatty acids, and probiotics/prebiotics are therapeutic factors that potentially modulate GI toxicity related to cancer treatments. Preclinical and clinical evidence are reviewed to critically define plausible benefits of these factors and their potential development into adjuncts to cancer chemotherapy. Mechanisms underlying the action of these nutrients are being unraveled in the laboratory. Optimal strategies to translate these findings into clinical care still remain to be elucidated. Key questions that remain to be answered include the following: which nutrient or combination of nutrients is selected for which patient and chemotherapy regimen? What mechanisms are responsible for modulation, and how are nutrient(s) administered in a clinically optimal manner? Research exploring interactions between different nutrients in GI protection is ongoing and demands further understanding. How nutrition preparations given to chemotherapy-treated patients are formulated in terms of component selection and dose optimization should be carefully studied and justified.

A prospective study of dietary polyunsaturated fatty acids and colorectal cancer risk in Chinese women

In animal models of colon cancer, n-3 polyunsaturated fatty acids (PUFA) have antineoplastic properties, whereas n-6 PUFAs may promote carcinogenesis. Prior epidemiologic studies have been inconsistent regarding the association of PUFAs and colorectal cancer. We prospectively evaluated the association between PUFA intake and colorectal cancer in a cohort of 73,242 Chinese women who were interviewed in person at the baseline survey for the Shanghai Women's Health Study. Dietary fatty acid consumption was derived using data collected from two food frequency questionnaires administered at baseline and 2 to 3 years later. The dietary total n-6 to n-3 PUFA ratio was strongly associated with colorectal cancer risk. Compared with women in the lowest quintile group, elevated relative risks (RR) were observed for the second [RR, 1.52; 95% confidence intervals (CI), 1.00-2.32], third (RR, 2.20; 95% CI, 1.41-3.45), fourth (RR, 1.65; 95% CI, 0.99-2.75), and fifth (RR, 1.95; 95% CI, 1.07-3.54) quintile groups. Arachidonic acid was associated with colorectal cancer risk with elevated RRs of 1.20(Q2-Q1) (95% CI, 0.87-1.64), 1.44(Q3-Q1) (95% CI, 1.05-1.98), 1.61(Q4-Q1) (95% CI, 1.17-2.23), and 1.39(Q5-Q1) (95% CI, 0.97-1.99; P(trend) = 0.03) with increasing dietary quintile. In a subset of 150 cancer cases and 150 controls, we found a statistically significant trend between an increasing n-6 to n-3 PUFA ratio and increasing production of prostaglandin E(2) (PGE(2)) as measured by urinary PGE(2) metabolites (P = 0.03). These results suggest that dietary PUFA and the ratio of n-6 to n-3 PUFA intake may be positively associated with colorectal cancer risk, and this association may be mediated in part through PGE(2) production.

Decreased polyunsaturated Fatty Acid content contributes to increased survival in human colon cancer

Among diet components, some fatty acids are known to affect several stages of colon carcinogenesis, whereas others are probably helpful in preventing tumors. In light of this, our aim was to determine the composition of fatty acids and the possible correlation with apoptosis in human colon carcinoma specimens at different Duke's stages and to evaluate the effect of enriching human colon cancer cell line with the possible reduced fatty acid(s). Specimens of carcinoma were compared with the corresponding non-neoplastic mucosa: a significant decrease of arachidonic acid, PPARα, Bad, and Bax and a significant increase of COX-2, Bcl-2, and pBad were found. The importance of arachidonic acid in apoptosis was demonstrated by enriching a Caco-2 cell line with this fatty acid. It induced apoptosis in a dose- and time-dependent manner via induction of PPARα that, in turn, decreased COX-2. In conclusion, the reduced content of arachidonic acid is likely related to carcinogenic process decreasing the susceptibility of cancer cells to apoptosis.

Oral administration of sodium butyrate reduces chemically-induced preneoplastic lesions in experimental carcinogenesis

OBJECTIVE: The objective was to assess the effects of oral administration of sodium butyrate on colon carcinogenesis. METHODS: Carcinogenesis in adult male Wistar rats was induced with 1.2-dimethylhydrazine injections at a dose of 40mg/kg of body weight. A solution of sodium butyrate (3.4%) was given ad libitum for 4 weeks (butyrate group, n=16) instead of water (control group, n=9). Rats were killed 17 weeks after 1.2-dimethylhydrazine administration. Aberrant crypt foci and expression of the messenger ribonucleic acid (mRNA) of cyclins D1 and E were quantified in the colon. Alterations in the fatty acid profile of the colon, liver, intra-abdominal fat and feces were also analyzed. RESULTS: A significant decrease in aberrant crypt foci was found in the group taking butyrate. No differences were found between the groups in the mRNA expression of cyclins D1 and E. Nevertheless, butyrate intake decreased the content of stearic and oleic acids in the intra-abdominal fat and docosahexaenoic acid in the liver. Moreover, these rats presented higher percentages of linoleic acid in the intra-abdominal fat than control rats. CONCLUSION: The data indicate that butyrate use in rats reduced preneoplastic lesions and changes in the intra-abdominal fat and fatty acid profile of the liver, commonly found in colon carcinogenesis.

Dietary fatty acids and recurrence of colorectal adenomas in a European intervention trial

Epidemiological studies have provided inconsistent data about the role of dietary fatty acids in colorectal cancer, and few studies have addressed their role in colorectal adenoma. The aim of the study was to assess the risk of overall adenoma recurrence associated with dietary consumption of total fat, subtypes of fat, and specific fatty acids (oleic acid, linoleic acid, alpha-linolenic acid). The study sample was composed of 523 patients with confirmed adenomas at the index colonoscopy, 35 to 75 yr old, who completed the European fiber-calcium intervention trial and had an initial dietary assessment using a qualitative and quantitative food questionnaire. The overall 3-yr recurrence rate was 22.6% (118 out of 523 patients). There were no significant associations between overall adenoma recurrence and either total fat, subtypes of fat, or specific fatty acids. However, polyunsaturated fatty acids and linoleic acid were both moderately but significantly associated with distal and multiple recurrence. No significant associations were observed with recurrence of proximal or advanced adenomas. Our findings do not support the hypothesis of strong associations between dietary fatty acids and recurrence of colorectal adenomas. The hypothesis of a differential role of specific fatty acids according to colorectal subsites deserves further investigation.

Multivariate explanatory model for sporadic carcinoma of the colon in Dukes' stages I and IIa

OBJECTIVE

We obtained before an explanatory model with six dependant variables: age of the patient, total cholesterol (TC), HDL cholesterol (HDL-C), VLDL cholesterol (VLDL-C), alkaline phosphatase (AP) and the CA 19.9 tumour marker. Our objective in this study was to validate the model by means of the acquisition of new records for an additional analysis.

DESIGN

Non-paired case control study.

SETTING

Urban and rural hospitals and primary health facilities in Western Andalusia and Extremadura (Spain).

PATIENTS

At both the primary care facilities and hospital level, controls were gathered in a prospective manner (n= 275). Cases were prospective and retrospective manner collected on (n=126).

MAIN OUTCOME MEASURES

Descriptive statistics, logistic regression and bootstrap analysis.

RESULTS

The AGE (odds ratio 1.02; 95% CI 1.003-1.037) (p= 0.01), the TC (odds ratio 0.986; 95% C.I. 0.980-0.992) (p< 0.001) and the CA 19.9 (odds ratio 1.023; 95% C.I. 1.012- 1.034) (p<0.001) were the variables that showed significant values at logistic regression analysis and bootstrap. Berkson's bias was statistically assessed.

CONCLUSIONS

The model, validated by means of logistic regression and bootstrap analysis, contains the variables AGE, TC, and CA 19.9 (three of the original six) and has a level 4 over 5 according to the criteria of Justice et al. (multiple independent validations) [Ann. Intern. Med.1999; 130: 515].

Relationships between intestinal polyp formation and fatty acid levels in plasma, erythrocytes, and intestinal polyps in Min mice

We have reported that a hyperlipidemic state is characteristic of Apc-deficient Min mice with multiple intestinal polyps. In our earlier case-control study, colorectal cancer risk showed positive relationships with erythrocyte membrane compositions of palmitic and oleic acids, but negative links with linoleic and arachidonic acids. To examine the roles of fatty acids in intestinal polyp formation, levels in plasma, erythrocytes, and intestinal polyps in Min mice were compared with those in wild-type mice. A diet free of eicosapentaenoic and docosahexaenoic acids with antineoplastic effects was fed to all mice from 6 to 15 weeks of age. Fatty acid levels were measured using accelerated solvent extraction and gas-liquid chromatography. Min mice with a hyperlipidemic state and multiple intestinal polyps had elevated values for palmitic and oleic acids in plasma and erythrocytes (at least P < 0.05), and higher plasma level of linoleic acid (P < 0.05). Arachidonic acid was 24.5% lower in erythrocytes (P < 0.0005), but did not differ in plasma. In Min mice, moreover, oleic and arachidonic acids were 1.78 and 1.43 times higher, respectively, in intestinal polyps than in paired normal mucosa (P < 0.05 and P < 0.01, respectively), but linoleic acid was 31.9% lower (P < 0.001). The present study suggests that palmitic, oleic, and arachidonic acids play key roles in intestinal polyp formation, and demonstrates reduced erythrocyte arachidonic acid values of Min mice, in line with our previous findings for patients with sporadic colorectal cancers.

Familial adenomatous polyposis patients have high levels of arachidonic acid and docosahexaenoic acid and low levels of linoleic acid and alpha-linolenic acid in serum phospholipids

Familial adenomatous polyposis (FAP) provides a model of APC inactivation as an early genetic event for the approximately 85% of colorectal cancers that develop from polyps. Abnormal fatty acid composition of tissues and serum phospholipids has been linked to cancer risk. Our aim was to describe the composition of fatty acids in serum phospholipids in 38 colectomized FAP patients as compared to 160 healthy subjects. Mean fatty acid intakes were similar between the groups. Colectomy was done on average 16 years prior to inclusion, and 18% were diagnosed with colorectal cancer at colectomy. The levels (weight %) of linoleic and alpha-linolenic acid were higher among the reference subjects (difference: 3.96, 95% confidence interval (CI) = 2.87, 5.04, and difference: 0.06, 95% CI = 0.04, 0.08, respectively), and the levels of arachidonic and docosahexaenoic acid were lower (difference: -3.70, 95% CI = -4.35, -3.06, and difference: -5.26, 95% CI = -6.25, -4.28, respectively) as compared to the FAP patients (all p < or = 0.0001). The abnormal fatty acid composition was not related to time since colectomy, intestinal reconstruction or history of colorectal cancer for any of the fatty acids assessed. Compositional differences in the fatty acid profile of serum phospholipids have not been described before in FAP patients. Further studies are needed to confirm these findings and assess clinical significances of a possible distorted fatty acid metabolism, including a potentially different dietary need of essential fatty acids. The relevance of these findings for APC induced cancers remains unclear.

CH-overtone regions as diagnostic markers for near-infrared spectroscopic diagnosis of primary cancers in human pancreas and colorectal tissue

We have investigated the application of near-infrared spectroscopy for detection of human primary pancreatic and colorectal cancers. Spectra from cancerous and normal tissue were collected from a total of 37 surgically resected pancreatic and colorectal patient tissue specimens using a fibre-optic probe. Major spectral differences were observed in the CH-stretching first (6,000-5,400 cm(-1)) and second overtone (9,000-7,900 cm(-1)) regions. By use of artificial neural networks, linear discriminant analysis, and cluster analysis as pattern-recognition methods the spectra were classified into cancerous and normal tissue groups with accuracy up to 89%. We also explored differences between the spectra obtained from colorectal and pancreatic tissue. Spectral data from cancerous and normal tissue were classified organ-specifically into four groups with accuracy between 80 and 83%. Our results indicate that CH-overtone regions, besides serving as diagnostic markers for NIR spectroscopic diagnosis of primary human pancreas and colorectal cancers, are also useful for elucidating differences between the spectra obtained from colorectal and pancreatic cancerous tissue.

Altered membrane free unsaturated fatty acid composition in human colorectal cancer tissue

Polyunsaturated free fatty acids (PUFAs) participate in normal functioning of the cell, particularly in control intracellular cell signalling. As nutritional components they compose a human diet with an indirect promoting influence on tumourogenesis. The PUFAs level depends on the functional state of the membrane. This work is focused on changes only of free unsaturated fatty acids amount (AA - arachidonic acid, LA - linoleic acid, ALA - alpha-linolenic acid, palmitoleic acid (PA) and oleic acid) in cell membranes of colorectal cancer of pT3 stage, G2 grade without metastasis. Qualitative and quantitative composition of free unsaturated fatty acids in the membrane was determined by high-performance liquid chromatography. It was shown that the malignant transformation was accompanied by a decrease in amount of LA and ALA while arachidonic and oleic acids increased. It is of interest that free AA levels are elevated in colon cancer, as AA is the precursor to biologically active eicosanoids.

Alpha-linolenic acid and the risk of prostate cancer. What is the evidence?

PURPOSE

Several studies have examined the association between polyunsaturated fatty acids and prostate cancer risk. We evaluated the evidence on the association between the essential polyunsaturated fatty acid, known as alpha-linolenic acid, and the risk of prostate cancer in humans.

MATERIALS AND METHODS

We comprehensively reviewed published studies on the association between alpha-linolenic acid and the risk of prostate cancer using MEDLINE.

RESULTS

A number of studies have shown a positive association between dietary, plasma or red blood cell levels of alpha-linolenic acid and prostate cancer. Other studies have demonstrated either no association or a negative association. The limitations of these studies include the assumption that dietary or plasma alpha-linolenic acid levels are positively associated with prostate tissue alpha-linolenic acid levels, and measurement errors of dietary, plasma and red blood cell alpha-linolenic acid levels.

CONCLUSIONS

More research is needed in this area before it can be concluded that there is an association between alpha-linolenic acid and prostate cancer.

Specific fatty acids and human colorectal cancer: an overview

BACKGROUND

Evidence suggests that dietary fats are associated with risk of colorectal cancer. The effect of fats depends not only on the quantity, but also on their composition in specific fatty acids. Moreover, fats are peroxidizable, and peroxidation products as well as antioxidants play a role in the pathogenic process of colorectal cancer.

METHODS

The published literature was reviewed for the relationship between dietary intake or concentration of specific fatty acids in adipose tissue, erythrocytes, plasma or feces in relation to colorectal cancer.

RESULTS

Increased concentrations of short-chain fatty acids (SCFAs) and eicosanopentaenoic acid (EPA) seem to protect against colorectal cancer. Increased concentrations of medium-chain fatty acids (MCFAs) and arachidonic acid (AA) might be associated with increased risk. Long-chain saturated fatty acids (LCSFAs) seem unrelated to colorectal cancer, while the associations between monounsaturated fatty acids (MUFAs), trans fatty acids, polyunsaturated fatty acids (PUFAs) such as linoleic acid (LA), alpha-linolenic acid (ALA), docosahexaenoic acid (DHA), omega-3/omega-6 ratio and colorectal cancer are unconvincing.

CONCLUSIONS

It is suggested that the substitution of food with high MCFAs and AA content by a SCFAs- and EPA-rich diet may contribute to reduced risk of colorectal cancer.

Assessment of risk associated with specific fatty acids and colorectal cancer among French-Canadians in Montreal: a case-control study

BACKGROUND

Discrepancies in findings on the association between dietary fats and colorectal cancer (CRC) persist, and it is hypothesized that fatty acids (FA) may modulate CRC risk because of their physiological functions.

METHODS

Between 1989 and 1993, a case-control study involving 402 cases and 668 population-based controls was conducted among French-Canadians. Dietary intake was assessed by a food frequency questionnaire.

RESULTS

Oleic acid was the major FA consumed by the study population. A significant inverse association was found among females between CRC and butyrate (OR = 0.57; 95% CI: 0.34-0.96; P = 0.006), alpha-linoleic acid (ALA) (OR = 0.78; 95% CI: 0.46-1.32; P = 0.016), and w-3 FA (OR = 0.84; 95% CI: 0.50-1.41; P = 0.028), comparing the upper to the lower quartiles of intake. An increased risk was associated with arachidonic acid (AA) (OR = 2.03; 95% CI: 1.16-3.54; P = 0.001) among males, and with the w6/w3 ratio (OR = 1.47; 95% CI: 0.86-2.50; P = 0.001) among females. Arachidonic acid was linked with up to fivefold increased risk (OR = 5.33; 95% CI: 2.04-13.95; P = 0.0004 for trend) among men with high vitamin C intake. Females with low carotenoids intake were at elevated risk associated with AA (OR = 4.07; 95% CI: 1.84-8.99; P = 0.003); eicosapentaenoic acid (OR = 3.50; 95% CI: 1.59-7.71; P = 0.015), and docosahexaenoic acid (OR = 5.77; 95% CI: 2.50-13.33; P = 0.002), comparing the upper with the lower quartiles of intake.

CONCLUSION

The results of this study suggest that independently of total energy intake, substituting AA by butyrate, ALA, or omega-3 FA may reduce CRC risk. The role of interactions between vitamin C, total carotenoids, and polyunsaturated FA requires further investigation.

Effect of olive oil on early and late events of colon carcinogenesis in rats: modulation of arachidonic acid metabolism and local prostaglandin E(2) synthesis

BACKGROUND

Animal model studies have shown that the colon tumour promoting effect of dietary fat depends not only on the amount but on its fatty acid composition. With respect to this, the effect of n9 fatty acids, present in olive oil, on colon carcinogenesis has been scarcely investigated.

AIMS

To assess the effect of an n9 fat diet on precancer events, carcinoma development, and changes in mucosal fatty acid composition and prostaglandin (PG)E(2) formation in male Sprague-Dawley rats with azoxymethane induced colon cancer.

METHODS

Rats were divided into three groups to receive isocaloric diets (5% of the energy as fat) rich in n9, n3, or n6 fat, and were administered azoxymethane subcutaneously once a week for 11 weeks at a dose rate of 7.4 mg/kg body weight. Vehicle treated groups received an equal volume of normal saline. Groups of animals were colectomised at weeks 12 and 19 after the first dose of azoxymethane or saline. Mucosal fatty acids were assessed at 12 and 19 weeks. Aberrant crypt foci and the in vivo intracolonic release of PGE(2) were assessed at week 12, and tumour formation at week 19.

RESULTS

Rats on the n6 diet were found to have colonic aberrant crypt foci and adenocarcinomas more often than those consuming either the n9 or n3 diet. There were no differences between the rats on the n9 and n3 diets. On the other hand, administration of both n9 and n3 diets was associated with a decrease in mucosal arachidonate concentrations as compared with the n6 diet. Carcinogen treatment induced an appreciable increase in PGE(2) formation in rats fed the n6 diet, but not in those fed the n3 and n9 diets.

CONCLUSIONS

Dietary olive oil prevented the development of aberrant crypt foci and colon carcinomas in rats, suggesting that olive oil may have chemopreventive activity against colon carcinogenesis. These effects may be partly due to modulation of arachidonic acid metabolism and local PGE(2) synthesis.

Dietary polyunsaturated fatty acids and cancers of the breast and colorectum: emerging evidence for their role as risk modifiers

The hypothesis that a high-fat diet promotes the development of postmenopausal breast cancer is supported by international data showing a strong correlation between fat intake and breast cancer rates and a modest positive association with high-fat diet in case-control studies. Dietary fat intake was found to be unrelated to the risk of breast cancer in cohort studies. In view of these conflicting findings it has been difficult to make nutritional recommendations for the prevention of breast cancer. Studies in animal models and recent observations in humans, however, have provided evidence that a high intake of omega-polyunsaturated fatty acids (PUFAs), stimulates several stages in the development of mammary and colon cancer, from an increase in oxidative DNA damage to effects on cell proliferation, free estrogen levels to hormonal catabolism. In contrast, fish oil-derived omega-3 fatty acids seem to prevent cancer by influencing the activity of enzymes and proteins related to intracellular signalling and, ultimately, cell proliferation. In this commentary, current evidence from experimental and human studies is summarized that implicates a high intake of omega-6 PUFAs in cancer of the breast, colon and, possibly, prostate and which indicates that omega-3 PUFAs and monounsaturated fatty acids such as oleic acid (omega-9) are protective. Plausible mechanisms for modulation of steps in the multistage carcinogenesis process by fats are discussed. Properly designed epidemiological studies are now needed, that integrate relevant biomarkers to unravel the contributions of different types of fat, their interactions with hormonal catabolism, protective nutritional factors and human cancer risk.

Plasma and mucosal fatty acid pattern in colectomized ulcerative colitis patients

Patients with inflammatory bowel disease (IBD) have increased plasma n3 polyunsaturated fatty acids (PUFAs), which in ulcerative colitis (UC) patients persists six months after colectomy, suggesting a primary abnormality in fatty acid (FA) metabolism in IBD. This finding needed to be confirmed in a larger series of UC long-term colectomized patients. We aimed to assess the plasma FA pattern in UC colectomized patients with either Brooke's ileostomy (UC-BI) or ileal pouch anal anastomosis (UC-IPAA) and the mucosal FA pattern in the ileal reservoir of the UC-IPAA patients. Plasma FAs were assessed in 63 UC colectomized patients (31 with BI and 32 with IPAA) and 30 controls. In 26 UC-IPAA (8 with pouchitis and 18 without pouchitis) and in 13 healthy controls gut mucosal FAs were also investigated. FAs were detected by capillary column gas-liquid chromatography. Increased levels of saturated fatty acids (SFAs) and decreased percentages of monounsaturated fatty acids (MUFAs) were observed in both groups of patients. There were no changes in plasma n3 and n6 PUFAs. The mucosal FA pattern of the ileal reservoir consisted of increased long-chain PUFAs, specially n6 PUFA, and a decrease of their essential precursors. High percentages of SFAs and low percentages of MUFAs were also seen. The plasma FA profile previously described in IBD is not observed long-term after colectomy in UC, suggesting that it is related with the presence of inflamed intestine. High concentrations of SFAs and decreased percentages of MUFAs might represent early events in disturbed FA metabolism in IBD. The changes in FAs of the ileal reservoir, which closely resemble those found in human and experimental IBD, probably represent a common pattern of intestinal inflammation.

Antioxidant enzymes and fatty acid status in erythrocytes of Down syndrome patients

The excess of genetic information in patients with Down syndrome (DS) produces an increase in the catalytic activity of superoxide dismutase (SOD1), an antioxidant enzyme coded on chromosome 21. It has been suggested that an increase in oxidative stress in DS patients may cause adverse effects in the cell membranes through the oxidation of polyunsaturated fatty acids (PUFAs). The aim of this study was to evaluate the cellular antioxidant system by determining the catalytic activity of the SOD1, glutathione peroxidase (GPx), catalase (CAT), and glutathione reductase (GR) enzymes and the concentrations of α-tocopherol in red blood cells (RBCs) in a group of 72 DS patients. The profile of fatty acids in the phospholipids of RBC membranes was also evaluated. The activity of the erythrocyte antioxidant enzymes is significantly higher in the DS group than in the control group (SOD1, 635 ± 70 U/g Hb vs 476 ± 67 U/g Hb; CAT, 1843 ± 250 U/g Hb vs 1482 ± 250 U/g Hb; GPx, 23.2 ± 5.3 U/g Hb vs 21.5 ± 3.6 U/g Hb; and GR, 9.32 ± 1.4 U/g Hb vs 6.9 ± 1.3 U/g Hb, respectively). No differences were observed in RBC α-tocopherol concentrations between the two groups studied. Long-chain n6 PUFA (C20:3n6, C20:4n6) concentrations were increased in DS patients, suggesting enhanced Δ-6-desaturase activity. The long-chain n3 PUFA (docosahexenoic acid) does not appear to be affected by increased oxidative stress, probably because of the existence of compensatory antioxidant mechanisms.