Reducing cell membrane n-6 fatty acids attenuate mucosal damage in food-sensitive enteropathy in mice

Bipolar disorder and the gut microbiome: A systematic review

OBJECTIVES

The microbiome is a rapidly advancing biomedical frontier with relevance for psychiatric illness. The gut microbiota interact with the central nervous system bidirectionally through the gut-brain axis and generate substances that may influence host metabolism, including short-chain fatty acids such as butyrate. Understanding gut microbiota in bipolar disorder (BD) may suggest new disease markers and treatment approaches.

METHODS

A PubMed search was performed on January 7, 2020 using terms "bipolar AND (microbiome OR microbiota)", for articles in English in which the study population included a distinct BD group and the gut microbiota/microbiome was assessed.

RESULTS

Thirteen articles met the inclusion criteria. In four of five studies that reported on group comparisons with respect to diversity, lower α-diversity was observed in BD relative to healthy controls (HC). The most convergent taxonomic finding was that in four studies, one particular clade distinguished gut microbiota between BD and HC: family Ruminococcaceae, genus Faecalibacterium, and species Faecalibacterium prausnitzii. Members of this clade, known for butyrate production, were reduced in BD relative to HC in three studies but elevated in a fourth. Additionally, genera Bacteroides or Bacteroides-Prevotella group species were elevated in BD in two studies but lower in a third.

CONCLUSIONS

Despite few studies and modest sample sizes, salient findings suggest that low α-diversity and dysbiosis with respect to abundance of Faecalibacterium and Bacteroides may characterize BD in both a trait and state-dependent fashion. Decreased richness and butyrate production also foster inflammation, which may be a hitherto unrecognized part of the pathophysiology underlying BD.

Switching to a Healthy Diet Prevents the Detrimental Effects of Western Diet in a Colitis-Associated Colorectal Cancer Model

Inflammatory bowel disease increases the odds of developing colitis-associated cancer. We hypothesized that Western-style diet (WD) aggravates azoxymethane (AOM)/dextran sulfate sodium salt (DSS)-induced colitis-associated tumorigenesis and that switching to the standard AIN93G diet will ameliorate disease symptoms even after cancer initiation. Female BALB/c mice received either WD (WD group) or standard AIN93G diet (AIN group) for the whole experimental period. After five weeks, the mice received 12.5 mg/kg AOM intraperitoneally, followed by three DSS cycles. In one group of mice, the WD was switched to AIN93G the day before starting the first DSS cycle (WD/AIN group). Feeding the WD during the whole experimental period aggravated colitis symptoms, shortened the colon (p < 0.05), changed microbiota composition and increased tumor promotion. On molecular level, the WD reduced proliferation (p < 0.05) and increased expression of the vitamin D catabolizing enzyme Cyp24a1 (p < 0.001). The switch to the AIN93G diet ameliorated this effect, reflected by longer colons, fewer (p < 0.05) and smaller (p < 0.01) aberrant colonic crypt foci, comparable with the AIN group. Our results show that switching to a healthy diet, even after cancer initiation is able to revert the deleterious effect of the WD and could be an effective preventive strategy to reduce colitis symptoms and prevent tumorigenesis.

Systematic Review of Gut Microbiota and Major Depression

Background: Recently discovered relationships between the gastrointestinal microbiome and the brain have implications for psychiatric disorders, including major depressive disorder (MDD). Bacterial transplantation from MDD patients to rodents produces depression-like behaviors. In humans, case-control studies have examined the gut microbiome in healthy and affected individuals. We systematically reviewed existing studies comparing gut microbial composition in MDD and healthy volunteers. Methods: A PubMed literature search combined the terms "depression," "depressive disorder," "stool," "fecal," "gut," and "microbiome" to identify human case-control studies that investigated relationships between MDD and microbiota quantified from stool. We evaluated the resulting studies, focusing on bacterial taxa that were different between MDD and healthy controls. Results: Six eligible studies were found in which 50 taxa exhibited differences (p < 0.05) between patients with MDD and controls. Patient characteristics and methodologies varied widely between studies. Five phyla-Bacteroidetes, Firmicutes, Actinobacteria, Fusobacteria, and Protobacteria-were represented; however, divergent results occurred across studies for all phyla. The largest number of differentiating taxa were within phylum Firmicutes, in which nine families and 12 genera differentiated the diagnostic groups. The majority of these families and genera were found to be statistically different between the two groups in two identified studies. Family Lachnospiraceae differentiated the diagnostic groups in four studies (with an even split in directionality). Across all five phyla, nine genera were higher in MDD (Anaerostipes, Blautia, Clostridium, Klebsiella, Lachnospiraceae incertae sedis, Parabacteroides, Parasutterella, Phascolarctobacterium, and Streptococcus), six were lower (Bifidobacterium, Dialister, Escherichia/Shigella, Faecalibacterium, and Ruminococcus), and six were divergent (Alistipes, Bacteroides, Megamonas, Oscillibacter, Prevotella, and Roseburia). We highlight mechanisms and products of bacterial metabolism as they may relate to the etiology of depression. Conclusions: No consensus has emerged from existing human studies of depression and gut microbiome concerning which bacterial taxa are most relevant to depression. This may in part be due to differences in study design. Given that bacterial functions are conserved across taxonomic groups, we propose that studying microbial functioning may be more productive than a purely taxonomic approach to understanding the gut microbiome in depression.

Phospholipid Fatty Acid Composition and Diamine Oxidase Activity of Intestinal Mucosa From Rats Treated With Irinotecan Hydrochloride (CPT-11) under Vegetable Oil–Enriched Diets: Comparison Between Perilla Oil and Corn Oil

BACKGROUND

Irinotecan hydrochloride (CPT-11), a topoisomerase I inhibitor highly effective for various cancers, has its dosage limited by diffuse mucosal damage with increased prostaglandin (PG) E(2). However, an analysis of intestinal phospholipid fatty acid composition after CPT-11 treatment has not been reported. This study aimed to evaluate intestinal phospholipid fatty acid composition in relation to intestinal mucosal integrity and plasma and mucosal PGE(2) levels after CPT-11 treatment. The effect of dietary vegetable oil supplementation, perilla oil vs corn oil, was also evaluated.

METHODS

Intestinal phospholipid fatty acid composition, PGE(2) level, mucosal diamine oxidase (DAO) activity, diarrhea, and blood tests were evaluated in rats injected with CPT-11 under a conventional diet. The same parameters were compared among 3 different dietary vegetable oil supplementations: perilla oil, corn oil, and a 1:3, respectively, mixture with a semisynthetic diet during 14 days.

RESULTS

CPT-11 treatment caused severe diarrhea, and intestinal mucosal fatty acid composition changed with increased PGE(2) level and decreased DAO activity. Decreases in eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and EPA/arachidonic acid (AA) ratio in colonic mucosa were observed. Perilla oil increased omega-3 polyunsaturated fatty acids, alpha-linolenic acid, EPA, and EPA/AA ratio and decreased plasma PGE(2). But the amounts used were not enough to attenuate intestinal damage from CPT-11 treatment.

CONCLUSIONS

CPT-11 induced changes of intestinal mucosal fatty acid composition with increased PGE(2) level and decreased intestinal integrity; perilla oil shows the possibility of being able to attenuate those changes.

ω-3 fatty acids attenuate mucosal inflammation in premature rat pups

BACKGROUND

Necrotizing enterocolitis (NEC) is a devastating intestinal disease of premature infants. Although ω-3 fatty acids are known to have antiinflammatory effects, their effect against NEC remains unclear.

METHODS

Mother rats fed a soybean-based, docosahexaenoic acid (DHA)- or eicosapentaenoic acid (EPA)-enriched diet from days 7 to 20 of gestation were examined. On day 20, the rat pups were delivered by abdominal incision, their intestines were removed, and messenger RNA was extracted. A rat NEC model was used to confirm the effects of ω-3 fatty acids on the inflamed intestine (n = 20-28). The expression of inflammatory molecules was analyzed by real-time polymerase chain reaction (n = 11-14).

RESULTS

The concentrations of DHA and EPA in the intestine were significantly increased in the DHA and EPA groups (P < .01). The expression of the antiinflammatory prostaglandin E2 receptor EP3 was increased in the DHA (P < .05) and EPA groups (P < .01). In the NEC model, the reduced incidence of colitis was confirmed in the DHA and EPA groups. The expression of peroxisome proliferator-activated receptor γ was increased (P < .05), and the inhibitor of nuclear factor-κB α/β decreased in both the DHA (P < .01) and EPA groups (P < .05).

CONCLUSION

Our findings indicate that ω-3 fatty acids are beneficial for protecting the premature intestine from inflammation by regulating eicosanoid- and nuclear factor-κB-related metabolite expression.

Bioecological control of inflammatory bowel disease

It is today generally accepted, that the intestinal bacterial flora is deeply involved in the pathogenesis of human inflammatory bowel diseases (IBDs), although the exact presence of unwanted or lack of specific crucial bacteria are not yet known. Westerners lack to large extent important immunomodulatory and fibre-fermenting lactic acid bacteria (LAB), bacteria which are present in all with a more primitive rural lifestyle. Acute reduction of flora is observed in disease, including IBD, as well as in mental and physical stress. Some observations suggest the mucosa has lost its ability of holding back the pathogenic flora and prevent close contacts between resident microflora and the epithelial surface. Among the manifestations of IBD are increased inflammation and coagulability, impaired cellular membrane function, exaggerated nitric oxide production and impaired short-chain fatty acid production. Animal studies suggest, in addition to reduced flora, an intimate association with immunostimulatory DNA, malfunctioning trifoil factors, increased splanchnic metabolism and reduced availability of natural antioxidants. Treatment with plant fibres, antioxidants and sometimes probiotics have had limited success. The most dramatic effects are seen in the few cases where total faecal replacement (TFR) has been tried. The general experience this far is that the best effects are obtained with compositions of probiotics rather than with single LAB treatments.

Modulation of neonatal immunological tolerance to ovalbumin by maternal essential fatty acid intake

The present study examines whether dietary essential fatty acid (EFA) intake influences the induction of oral tolerance to ovalbumin (OA) in neonatal and adult rats. During late gestation and throughout lactation Sprague-Dawley rats were fed a diet supplemented (S) with EFA (7% soybean oil), or a diet deficient (D) in EFA (7% hydrogenated lard). The rat offspring were subsequently exposed to OA either via the milk at 10-16 days (neonatal rats), or as adults via the drinking water at 7-9 wk of age. Oral administration of OA to the adult rats lead to suppression of the delayed-type hypersensitivity (DTH) reactivity and IgG antibody response against OA, which was not influenced by their diets. In the offspring of the dams fed the D diet antigen exposure via the milk resulted in suppression of the serum antibody levels and DTH reaction against OA indicating induction of oral tolerance. Higher transforming growth factor beta (TGF-beta) mRNA levels in the draining lymph nodes suggested this to be mediated by regulatory T cells. In contrast, OA exposure of the dams fed the S diet did not result in a suppressed OA response of their offspring. Thus, the quality of FA ingested by the mother may have effects on the development of immunological tolerance to dietary antigens in the offspring. Our results might have importance for the understanding of the increase in allergy related to the Western type of diet.

Fatty acids in colostrum from mothers of children at high risk of atopy in relation to clinical and laboratory signs of allergy in the first year of life

BACKGROUND

It remains controversial whether fatty acid (FA) composition of breast milk relates to development of atopy in the infant. This study evaluates FA in colostrum from mothers of children at high risk of atopy in association with atopy at the age of 1 year.

METHODS

The FA of colostrum were analyzed for 218 children (60 with low birth weight between 1500 and 2500 g, 84 with a history of maternal atopy, and 74 with an elevated cord blood immunoglobulin (Ig)E of >0.9 IU/ml). Total lipids were extracted, methylated and separated by gas-liquid chromatography. Laboratory screening for allergic sensitization and clinical examination took place within the Leipzig Allergy Risk Children's Study (LARS).

RESULTS

Low birth weight was correlated with low percentage levels of 20:2n-6, 22:2n-6, and 22:3n-3 (r = 0.14, P < 0.05; r = 0.14, P < 0.05 and r = 0.20, P < 0.01, respectively) and low gestational age at birth was correlated with low 22:3n-3 (r = 0.15, P < 0.05). There was no association between FA and atopic eczema at the age of 1 year. However, high linoleic acid (LA, 18:2n-6) was linked to high specific IgE against cow's milk protein (P < 0.05), and low docosapentaenoic acid (DPA, 22:5n-3) was associated with elevated total serum IgE (P < 0.05) at the age of 1 year, respectively.

CONCLUSIONS

The polyunsaturated fatty acid composition of colostrum in a high risk newborn population shows associations with atopic sensitization at the age of 1 year and may be predictive for later atopic disease.

Fatty acid and sn-2 fatty acid composition in human milk from Granada (Spain) and in infant formulas

OBJECTIVE

To investigate differences in fatty acid and sn-2 fatty acid composition in colostrum, transitional and mature human milk, and in term infant formulas.

SETTING

Departament de Nutrició i Bromatologia, University of Barcelona, Spain and University Hospital of Granada, Spain.

SUBJECTS

One-hundred and twenty mothers and 11 available types of infant formulas for term infants.

DESIGN

We analysed the fatty acid composition of colostrum (n=40), transitional milk (n=40), mature milk (n=40) and 11 infant formulas. We also analysed the fatty acid composition at sn-2 position in colostrum (n=12), transitional milk (n=12), mature milk (n=12), and the 11 infant formulas.

RESULTS

Human milk in Spain had low saturated fatty acids, high monounsaturated fatty acids and high linolenic acid. Infant formulas and mature human milk had similar fatty acid composition. In mature milk, palmitic acid was preferentially esterified at the sn-2 position (86.25%), and oleic and linoleic acids were predominantly esterified at the sn-1,3 positions (12.22 and 22.27%, respectively, in the sn-2 position). In infant formulas, palmitic acid was preferentially esterified at the sn-1,3 positions and oleic and linoleic acids had higher percentages at the sn-2 position than they do in human milk.

CONCLUSION

Fatty acid composition of human milk in Spain seems to reflect the Mediterranean dietary habits of mothers. Infant formulas resemble the fatty acid profile of human milk, but the distribution of fatty acids at the sn-2 position is markedly different.

Influence of probiotic supplemented infant formula on composition of plasma lipids in atopic infants

Probiotic therapy is a new, successful approach to alleviating allergic symptoms. In this study, our aim was to investigate whether the positive results obtained with probiotic therapy would be associated with the differential absorption and utilization of dietary PUFA. 15 infants referred to a pediatric clinic on the basis of atopic eczema were weaned to Bifidobacterium Bb-12 or Lactobacillus GG supplemented infant formula, or to the same formula without probiotics (randomized, placebo-controlled, double blind study design). In plasma neutral lipids, alpha-linolenic acid (18:3 n-3) proportions were reduced by the probiotic supplementation. In phospholipids, Lactobacillus GG supplemented formula did not influence alpha-linolenic acid proportions, while Bifidobacterium Bb-12 supplemented formula increased the proportion of alpha-linolenic acid; from 0.13 +/- 0.03 to 0.24 +/- 0.03 (mean +/- SEM) (P = 0.002). These results show that some physiological effects of probiotics may be associated with physiological interactions between probiotics and dietary PUFA.

Effects of n-3 polyunsaturated fatty acids on dermatitis in NC/Nga mice

The administration of n-3 polyunsaturated fatty acids (PUFAs) is known to be effective against allergic diseases by suppressing the production of eicosanoids derived from arachidonic acid. To investigate the mechanisms and efficacy of n-3 PUFA treatment in patients with atopic dermatitis (AD), we administered four different formulas of alpha-linolenic acid for 6 weeks in an AD model using NC/Nga mice. According to the doses of alpha-linolenic acid given, the levels of alpha-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid in the red blood cell membranes increased while the levels of linoleic acid and arachidonic acid decreased. However, there was no significant difference among the four dose groups in clinical skin severity score, histopathological findings of skin lesions, or levels of total plasma IgE. Moreover, there was no significant difference in the production of leukotriene B(4) and Leukotriene C(4) from skin lesions after stimulation with A23187 among the groups, although the production of prostaglandin E(2) (PGE(2)) was significantly reduced and skin blood flow in the ear was significantly higher in the group given the highest dose of alpha-linolenic acid. Our results suggest that the administration of alpha-linolenic acid can change the fatty acid composition, PGE(2) production, and skin blood flow but may not prevent the development of dermatitis in NC/Nga mice.

Polyunsaturated fatty acids in maternal diet, breast milk, and serum lipid fatty acids of infants in relation to atopy

BACKGROUND

The increased consumption of n-6 polyunsaturated fatty acids (PUFA) has been shown to coincide with the increased prevalence of atopic diseases. We aimed to investigate whether maternal diet and atopic status influence the PUFA composition of breast milk and the serum lipid fatty acids of infants.

METHODS

Maternal diet was assessed by a food questionnaire. The PUFA composition of breast milk obtained at 3 months from 20 allergic and 20 healthy mothers and of their infants' (10 atopic and 10 nonatopic/group of mothers) serum lipids was analyzed.

RESULTS

Although no differences in maternal PUFA intake were observed, the breast milk of allergic mothers contained less gamma-linolenic acid (18:3 n-6) than that of healthy mothers. Similarly, atopic infants had less gamma-linolenic acid in phospholipids than healthy infants, although n-6 PUFA were elevated in other serum lipid fractions in atopic infants. The serum lipid fatty acids in atopic infants did not correlate with those in maternal breast milk.

CONCLUSION

Our results suggest that dietary n-6 PUFA are not as readily transferred into breast milk or incorporated into serum phospholipids, but may be utilized for other purposes, such as eicosanoid precursors, in allergic/atopic individuals. Subsequently, high dietary proportions of n-6 PUFA, or reduced proportions of regulatory PUFA, such as gamma-linolenic acid and n-3 PUFA, may be a risk factor for the development of atopic disease.

The influence of polyunsaturated fatty acids on probiotic growth and adhesion

The establishment of the intestinal microflora, and probiotic bacteria, may control the inflammatory conditions in the gut. As polyunsaturated fatty acids (PUFA) possess antimicrobial activities, they may deter the action of probiotics. We assessed whether free linoleic, gamma-linolenic, arachidonic, alpha-linolenic and docosahexaenoic acids at physiological concentrations in the growth media would influence the growth and adhesion of Lactobacillus GG (probiotic), Lactobacillus casei Shirota (probiotic) and Lactobacillus bulgaricus (dairy strain). Higher concentrations of PUFA (10-40 microg PUFA ml(-1)) inhibited growth and mucus adhesion of all tested bacterial strains, whilst growth and mucus adhesion of L. casei Shirota was promoted by low concentrations of gamma-linolenic acid and arachidonic acid (at 5 microg ml(-1)), respectively. PUFA also altered bacterial adhesion sites on Caco-2 cells. Caco-2 cells grown in the presence of arachidonic acid were less adhered to by all three bacterial strains. Yet, L. casei Shirota adhered better on Caco-2 cells grown in the presence of alpha-linolenic acid. As the adhesion to mucosal surfaces is pivotal in health promoting effects by probiotics, our results indicate that the action of probiotics in the gut may be modulated by dietary PUFA.

Benefits and risks of elimination diets

Elimination diets have been used for the prevention or treatment of allergic disease with the diet of the pregnant or breastfeeding mother or the child, or both, being modulated as deemed appropriate. Evidence from studies published so far suggests that dietary restrictions are in fact effective only in the treatment of specific food allergies, not in allergy prevention. An elimination diet of a child or a breastfeeding mother entails a risk to normal nutrition and growth of the child. Although studies are lacking, dietary restrictions during lactation may well be harmful also to the mother's health. Substitution of nutritionally important foods and professional guidance are necessary for the successful treatment of food allergies.

Dietary fatty acids and allergy

The increase in the prevalence of atopic diseases has recently been linked to altered consumption of polyunsaturated fatty acids (PUFAs). As typical Western diets contain almost 10 times more linoleic acid (18:2 omega-6) than alpha-linolenic acid (18:3 omega-3), it is the metabolism of the former that predominates. Subsequently produced arachidonic acid-derived eicosanoids alter the balance of T-helper cells type 1 and type 2 thus favouring the production of immunoglobulin (Ig)E. In atopic subjects, the impact of this excessive eicosanoid production may be further strengthened as a result of changes in cyclic nucleotide metabolism exacerbated by substrate availability. Dietary omega-3 fatty acids can have marked influence on both specific and nonspecific immune responses in modifying eicosanoid production and replacing omega-6 fatty acids in cell membranes. Therefore, it is concluded that careful manipulation of dietary PUFAs may play a key role in the successful management of inflammation associated with atopic diseases.

Fatty acids in substitute formulas for cow's milk allergy

BACKGROUND

The role of dietary fats in food-related allergic symptoms is increasingly being investigated, since the pivotal role of fat-derived inflammatory substances, e.g., leukotrienes, has been realized. The objective of this study was to describe the fatty acid composition of several commercially available infant formulas that are used as substitutes for adapted cow's milk formulas.

METHODS

Samples of nine formulas (two soy, two extensively hydrolyzed casein, three extensively hydrolyzed whey, and two amino-acid-based formulas) and human milk as control were analyzed by gas chromatography.

RESULTS

The quantity of fatty acids in the formulas was within the breast-milk range. The percentage of energy derived from fat was below the European Society for Pediatric Gastroenterology and Nutrition recommendations in two cases, but, in the others, it roughly met the recommendations. The percentage of energy derived from linoleic acid was as recommended in all but two cases, where it was higher than recommended. As indicated by a quality indicator, the linoleic to alpha-linolenic acid ratio, altogether four formulas were within either the recommendations or the analyzed breast-milk range. In three cases, it was 1.5-2.5 and in two cases 4-5 times higher than recommended.

CONCLUSIONS

There are recommendations for infant formulas to meet nutritional requirements of fat intake, and the analyzed formulas are in most cases within the suggested ranges. However, little is known of requirements in allergic or inflammatory conditions, and whether these described fatty acid compositions are pro- or anti-inflammatory.

Management of food allergy

Our present options for the management of food allergy are avoidance and pharmacotherapy. There are, however, many promising perspectives for better future management such as the more extensive use of hydrolyzed and elemental formulas for therapy and prevention, or greater emphasis on diagnosis and treatment of accompanying diseases linked with increased gut permeability. In selected situations, specific immunotherapy might be helpful. Rapid progress is expected in the search for the conditions of induction of oral tolerance. The latest results in genetic engineering can give us very effective tools for mass production of less allergenic foods with high nutritional value--if all safety, stability, productivity, and antigenicity problems can be solved.

Chronic oral antigen exposure induces lymphocyte migration in anaphylactic mouse intestine

Persistent diarrhea, vomiting, and dehydration are symptoms often seen in patients suffering from food allergy after chronic antigen exposure; however, the precise mechanisms involved have not been well defined. In an effort to clarify the mechanisms of the chronic intestinal changes attributable to genuine IgE-mediated anaphylactic reactions induced by orally administered antigen, a mouse model was established by s.c. implantation of a murine hybridoma capable of producing monoclonal anti-trinitrophenyl IgE antibody, and the morphologic and immunologic changes occurring in the intestine upon chronic antigen exposure were investigated. In the early stage after ingestion of the antigen, diarrhea and noticeable infiltration of mast cells as well as eosinophils into the lamina propria were observed. A substantial increase in serum histamine levels as well as an increase in leukotriene C4 synthesis in the jejunal mucosa were observed 1 h after antigen challenge. Also, the synthesis of leukotriene B4 was significantly elevated for up to 9 h after antigen challenge. The expression of both intercellular adhesion molecule-1 (ICAM-1) on mucosal vascular endothelial cells and IAd on epithelial cells was markedly enhanced, and noticeable infiltration of eosinophils and lymphocytes was also confirmed in the mouse model after chronic antigen exposure. These findings suggest that oral antigen exposure induces anaphylactic reactions in the intestine mediated by mast cells and eosinophils in response to the IgE-antigen complex in the early phase, and also induces lymphocyte migration after chronic antigen exposure.