Combinations of distinct long-chain polyunsaturated fatty acid species for improved dietary treatment against allergic bronchial asthma

Severe Allergy as a Chronic Inflammatory Condition From a Systems Biology Perspective

Persistent and unresolved inflammation is a common underlying factor observed in several and seemingly unrelated human diseases, including cardiovascular and neurodegenerative diseases. Particularly, in atopic conditions, acute inflammatory responses such as those triggered by insect venom, food or drug allergies possess also a life-threatening potential. However, respiratory allergies predominantly exhibit late immune responses associated with chronic inflammation, that can eventually progress into a severe phenotype displaying similar features as those observed in other chronic inflammatory diseases, as is the case of uncontrolled severe asthma. This review aims to explore the different facets and systems involved in chronic allergic inflammation, including processes such as tissue remodelling and immune cell dysregulation, as well as genetic, metabolic and microbiota alterations, which are common to other inflammatory conditions. Our goal here was to deepen on the understanding of an entangled disease as is chronic allergic inflammation and expose potential avenues for the development of better diagnostic and intervention strategies.

Association between Polyunsaturated Fatty Acid Profile and Bronchial Inflammation in Bronchiolitis Obliterans

Introduction

Bronchiolitis obliterans (BO) is a chronic lung disease, which occurs after an insult to the lower airways, in particular after airway infections or after stem cell transplantation, and which results in persistent inflammation. N-3 and n-6 polyunsaturated fatty acids (PUFA) have been shown to influence the inflammatory processes in chronic inflammatory conditions. Since BO is maintained by persistent pulmonary inflammation, a disbalanced n-6/n-3 fatty acid profile could support the inflammatory process in patients with BO and therefore, could become an approach to new therapeutic options.

Methods

Twenty-five patients with BO (age: 13; 7-39) and 26 healthy controls (age: 19; 7-31) participated in the study. Lung function (forced viral capacity (FVC), forced expiratory volume 1 (FEV1), residual volume (RV)), and lung clearance index (LCI) were measured. Induced sputum was analyzed for cytology and cytokine levels (IL-1ß, IL-6, IL-8, TNF-α) using cytometric bead array (CBA). The PUFA profile was determined in the serum and induced sputum by gas chromatography.

Results

Patients presented with significantly lower FVC and FEV1 as well as higher RV and LCI measurements compared to the control group. Apart from a massive airway inflammation indicated by elevated numbers of total cells and neutrophils, the CBA analysis showed significantly increased levels of IL-1β, IL-6, and IL-8. The analysis of PUFA in sputum and serum revealed a significant difference in the ratio between the n-6 PUFA arachidonic acid (AA) and the n-3 PUFA docosahexaenoic acid (DHA) (AA : DHA). Furthermore, the AA : DHA ratio significantly correlated with the inflammatory cytokines in induced sputum.

Conclusion

Lung function in BO is significantly impaired and associated with uncontrolled neutrophil-dominated airway inflammation. Furthermore, the imbalance in the AA/DHA ratio in favor of n-6 PUFA demonstrates a pro-inflammatory microenvironment in the cell membrane, which correlates with the inflammatory cytokines in induced sputum and might be an option for an anti-inflammatory therapy in BO.

Effects of low-dust forages on dust exposure, airway cytology, and plasma omega-3 concentrations in Thoroughbred racehorses: A randomized clinical trial

BACKGROUND

Racehorses commonly develop evidence of mild asthma in response to dust exposure. Diets deficient in omega-3 polyunsaturated fatty acids (Ω-3) might exacerbate this response.

HYPOTHESIS

To compare dust exposure, bronchoalveolar lavage fluid (BALF) cytology, and plasma Ω-3 and specialized pro-resolving mediators (SPM) concentrations amongst racehorses fed dry hay, steamed hay, and haylage.

ANIMALS

Forty-three Thoroughbred racehorses.

METHODS

Prospective clinical trial. Horses were randomly assigned to be fed dry hay, steamed hay, or haylage for 6 weeks. Measures of exposure to dust in the breathing zone were obtained twice. At baseline, week-3, and week-6, BALF cytology was examined. Plasma lipid profiles and plasma SPM concentrations were examined at baseline and week 6. Generalized linear mixed models examined the effect of forage upon dust exposure, BALF cytology, Ω-3, and SPM concentrations.

RESULTS

Respirable dust was significantly higher for horses fed hay (least-square mean ± s.e.m. 0.081 ± 0.007 mg/m³ ) when compared with steamed hay (0.056 ± 0.005 mg/m³ , P = .01) or haylage (0.053 ± 0.005 mg/m³ , P < .01). At week 6, BALF neutrophil proportions in horses eating haylage (3.0% ± 0.6%) were significantly lower compared with baseline (5.1 ± 0.7, P = .04) and horses eating hay (6.3% ± 0.8%, P < .01). Plasma eicosapentaenoic acid to arachidonic acid ratios were higher in horses eating haylage for 6 weeks (0.51 ± 0.07) when compared with baseline (0.34 ± 0.05, P < .01) and horses eating steamed (0.24 ± 0.02, P < .01) or dry hay (0.25 ± 0.03, P < .01).

CONCLUSIONS AND CLINICAL IMPORTANCE

Steamed hay and haylage reduce dust exposure compared with dry hay, but only haylage increased the ratio of anti-inflammatory to pro-inflammatory lipids while reducing BAL neutrophil proportions within 6 weeks.

Effects of Coix Seed Oil on High Fat Diet-Induced Obesity and Dyslipidemia

Dietary intervention is becoming more popular as a way to improve lipid metabolism and reduce the prevalence of diet-related chronic disorders. We evaluated the effects of several dietary oils on body weight, fat mass, liver weight, and tumor necrosis factor in obese mice given a high-fat diet (HFD) to discover if coix seed oil (CSO) had an anti-obesity impact. As compared to other dietary fats, CSO treatment considerably lowered body weight and liver index, successfully sup-pressed total cholesterol and triglyceride content, and raised liver lipid deposition and lipid metabolism problem induced by high fat intake. Furthermore, gas chromatography research revealed that CSO extracted by supercritical fluid, with 64% being CSO extracted by supercritical fluid, and the greatest amounts of capric acids and lauric acids being 35.28% and 22.21%, respectively. CSO contained a high content of medium-chain fatty acids and was able to modify hepatic fatty acid metabolism and lipid levels in HFD-induced obese mice. According to the results, CSO has the potential to replace dietary lipids as a promising functional lipid in the prevention of met-abolish disorders.

Oil supplementation with a special combination of n-3 and n-6 long-chain polyunsaturated fatty acids does not protect for exercise induced asthma: a double-blind placebo-controlled trial

BACKGROUND

Many patients suffering from exercise-induced asthma (EIA) have normal lung function at rest and show symptoms and a decline in FEV₁ when they do sports or during exercise-challenge. It has been described that long-chain polyunsaturated fatty acids (LCPUFA) could exert a protective effect on EIA.

METHODS

In this study the protective effect of supplementation with a special combination of n-3 and n-6 LCPUFA (sc-LCPUFA) (total 1.19 g/ day) were investigated in an EIA cold air provocation model.

PRIMARY OUTCOME MEASURE

Decrease in FEV₁ after exercise challenge and secondary outcome measure: anti-inflammatory effects monitored by exhaled NO (eNO) before and after sc-LCPUFA supplementation versus placebo.

RESULTS

Ninety-nine patients with exercise-induced symptoms aged 10 to 45 were screened by a standardized exercise challenge in a cold air chamber at 4 °C. Seventy-three patients fulfilled the inclusion criteria of a FEV₁ decrease > 15% and were treated double-blind placebo-controlled for 4 weeks either with sc-LCPUFA or placebo. Thirty-two patients in each group completed the study. Mean FEV₁ decrease after cold air exercise challenge and eNO were unchanged after 4 weeks sc-LCPUFA supplementation.

CONCLUSION

Supplementation with sc-LCPUFA at a dose of 1.19 g/d did not have any broncho-protective and anti-inflammatory effects on EIA.

TRIAL REGISTRATION

Clinical trial registration number: NCT02410096. Registered 7 February 2015 at Clinicaltrial.gov.

A combination of LCPUFA ameliorates airway inflammation in asthmatic mice by promoting pro-resolving effects and reducing adverse effects of EPA

Lipid mediators derived from omega (n)-3 and n-6 long-chain polyunsaturated fatty acids (LCPUFA) play key roles in bronchoconstriction, airway inflammation, and resolution processes in asthma. This study compared the effects of dietary supplementation with either a combination of LCPUFAs or eicosapentaenoic acid (EPA) alone to investigate whether the combination has superior beneficial effects on the outcome of asthmatic mice. Mice were sensitized with house dust mite (HDM) extract, and subsequently supplemented with either a combination of LCPUFAs or EPA alone in a recall asthma model. After the final HDM and LCPUFA administration, airway hyperresponsiveness (AHR), bronchoalveolar lavages, and lung histochemistry were examined. Lipid mediator profiles were determined by liquid chromatography coupled with tandem mass spectrometry (LC-MS-MS). The LCPUFA combination reduced AHR, eosinophilic inflammation, and inflammatory cytokines (IL-5, IFN-γ, and IL-6) in asthmatic mice, whereas EPA enhanced inflammation. The combination of LCPUFAs was more potent in downregulating EPA-derived LTB₅ and LTC₅ and in supporting DHA-derived RvD1 and RvD4 (2.22-fold and 2.58-fold higher levels) than EPA alone. Ex vivo experiments showed that LTB₅ contributes to granulocytes' migration and M1-polarization in monocytes. Consequently, the LCPUFA combination ameliorated airway inflammation by inhibiting adverse effects of EPA and promoting pro-resolving effects supporting the lipid mediator-dependent resolution program.

Higher Omega-3 Index Is Associated with Better Asthma Control and Lower Medication Dose: A Cross-Sectional Study

Asthma is a chronic inflammatory airway disease, associated with systemic inflammation. Omega-3 polyunsaturated fatty acids (n-3 PUFA) have established anti-inflammatory effects, thus having potential as an adjunct therapy in asthma. This study aimed to compare erythrocyte n-3 PUFA in adults with (n = 255) and without (n = 137) asthma and determine the relationship between erythrocyte n-3 PUFA and clinical asthma outcomes. Subjects had blood collected, lung function measured and Juniper Asthma Control Questionnaire (ACQ) score calculated. Fatty acids were measured in erythrocyte membranes by gas chromatography, and the omega-3 index (O3I) was calculated (% eicosapentaenoic acid + % docosahexaenoic acid). O3I was similar in subjects with and without asthma (p = 0.089). A higher O3I was observed in subjects with controlled or partially controlled asthma (ACQ < 1.5) compared to subjects with uncontrolled asthma (ACQ ≥ 1.5) (6.0% (5.4–7.2) versus 5.6% (4.6–6.4) p = 0.033). Subjects with a high O3I (≥8%) had a lower maintenance dose of inhaled corticosteroids (ICS) compared to those with a low O3I (<8%) (1000 μg (400–1000) versus 1000 μg (500–2000) p = 0.019). This study demonstrates that a higher O3I is associated with better asthma control and with lower ICS dose, suggesting that a higher erythrocyte n-3 PUFA level may have a role in asthma management.

A combination of LCPUFAs regulates the expression of miRNA-146a-5p in a murine asthma model and human alveolar cells

BACKGROUND

LCPUFAs are suggestive of having beneficial effects on inflammatory diseases such as asthma. However, little is known about the modulative capacity of omega-(n)-3 and n-6 LCPUFAs within the epigenetic regulation of inflammatory processes.

OBJECTIVE

The aim of this study was to investigate whether a specific combined LCPUFA supplementation restores disease-dysregulated miRNA-profiles in asthmatic mice. In addition, we determined the effect of the LCPUFA supplementation on the interaction of the most regulated miRNA expression and oxygenase activity in vitro.

METHODS

Sequencing of miRNA was performed by NGS from lung tissue of asthmatic and control mice with normal diet, as well as of LCPUFA supplemented asthmatic mice. Network analysis and evaluation of the biological targets of the miRNAs were performed by DIANA- miRPath v.3 webserver software, TargetScanMouse 7.2, and tool String v.10, respectively. Expression of hsa-miRNA-146a-5p and activity of COX-2 and 5-LO in LCPUFA-treated A549 cells were assessed by qPCR and flow cytometry, respectively.

RESULTS

In total, 62 miRNAs were dysregulated significantly in murine allergic asthma. The LCPUFA combination restored 21 of these dysregulated miRNAs, of which eight (mmu-miR-146a-5p, -30a-3p, -139-5p, -669p-5p, -145a-5p, -669a-5p, -342-3p and -15b-5p) were even normalized compared to the control levels. Interestingly, six of the eight rescued miRNAs are functionally implicated in TGF-β signaling, ECM-receptor interaction and fatty acid biosynthesis. Furthermore, in vitro experiments demonstrated that upregulation of hsa-miRNA-146a-5p is accompanied by a reduction of COX-2 and 5-LO activity. Moreover, transfection experiments revealed that LCPUFAs inhibit 5-LO activity in the presence and absence of anti-miR-146a-5p.

CONCLUSION

Our results demonstrate the modulative capacity of LCPUFAs on dysregulated miRNA expression in asthma. In addition, we pointed out the high regulative potential of LCPUFAs on 5-LO regulation and provided evidence that miR-146a partly controls the regulation of 5-LO.

A specific combined long-chain polyunsaturated fatty acid supplementation reverses fatty acid profile alterations in a mouse model of chronic asthma

Background

The immune-modulating potential of long-chain polyunsaturated fatty acids (LCPUFAs) based on their conversion into lipid mediators in inflammatory situations has been proven by several studies. Respecting the immune-modulative role of lipid mediators in bronchoconstriction, airway inflammation and resolution of inflammatory processes, LCPUFAs play an important role in asthma. To design a disease-specific and most beneficial LCPUFA supplementation strategy, it is essential to understand how asthma alters LCPUFA profiles. Therefore, this study characterizes the alterations of LCPUFA profiles induced by allergic asthma. In addition, this study explores whether a simple eicosapentaenoic acid (EPA) alone or a specific combined LCPUFA supplementation could restore imbalanced LCPUFA profiles.

Methods

Mice were sensitized with a daily dose of 40 μg house dust mite (HDM)-extract in a recall model and fed with either normal diet, EPA or a specific combined (sc)-LCPUFA supplementation containing EPA, docosahexaenoic acid (DHA), γ -linolenic acid (GLA) and stearidonic acid (SDA) for 24 days. After recall with HDM, mice were sacrificed and blood and lung tissue were collected. Fatty acid profiles were determined in plasma, blood cells and lung cells of asthmatic mice by capillary gas-chromatography.

Results

In lung cells of asthmatic mice, arachidonic acid (AA, p < 0.001) and DHA (p < 0.01) were increased while dihomo-γ-linolenic acid (DGLA, p < 0.05) was decreased. EPA supplementation increased only EPA (p < 0.001) and docosapentaenoic acid (DPA, p < 0.001), but neither DGLA nor DHA in lung cells of asthmatic mice. In contrast, a specific combined dietary supplementation containing n-3 and n-6 LCPUFAs could decrease AA (p < 0.001), increase EPA (p < 0.001), DPA (p < 0.001) and DHA (p < 0.01) and could reverse the lack of DGLA (p < 0.05).

Conclusions

In summary, allergic asthma alters LCPUFA profiles in blood and lung tissue. In contrast to the EPA supplementation, the distinct combination of n-3 and n-6 LCPUFAs restored the LCPUFA profiles in lung tissue of asthmatic mice completely. Subsequently, sc-LCPUFA supplementation is likely to be highly supportive in limiting and resolving the inflammatory process in asthma.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0947-6) contains supplementary material, which is available to authorized users.

Dietary ω-3 fatty acids alter the lipid mediator profile and alleviate allergic conjunctivitis without modulating Th2 immune responses

Allergic conjunctivitis (AC) is one of the most common ocular surface diseases in the world. In AC, T helper type 2 (T_h2) immune responses play central roles in orchestrating inflammatory responses. However, the roles of lipid mediators in the onset and progression of AC remain to be fully explored. Although previous reports have shown the beneficial effects of supplementation of ω-3 fatty acids in asthma or atopic dermatitis, the underlying molecular mechanisms are poorly understood. In this study, a diet rich in ω-3 fatty acids alleviated AC symptoms in both early and late phases without affecting T_h2 immune responses, but rather by altering the lipid mediator profiles. The ω-3 fatty acids completely suppressed scratching behavior toward the eyes, an allergic reaction provoked by itch. Although total serum IgE levels and the expression levels of T_h2 cytokines and chemokines in the conjunctiva were not altered by ω-3 fatty acids, eosinophil infiltration into the conjunctiva was dramatically suppressed. The levels of ω-6–derived proinflammatory lipid mediators, including those with chemoattractant properties for eosinophils, were markedly reduced in the conjunctivae of ω-3 diet–fed mice. Dietary ω-3 fatty acids can alleviate a variety of symptoms of AC by altering the lipid mediator profile.—Hirakata, T., Lee, H.-C., Ohba, M., Saeki, K., Okuno, T., Murakami, A., Matsuda, A., Yokomizo, T. Dietary ω-3 fatty acids alter the lipid mediator profile and alleviate allergic conjunctivitis without modulating T_h2 immune responses.

Pollution and respiratory disease: can diet or supplements help? A review

Pollution is known to cause and exacerbate a number of chronic respiratory diseases. The World Health Organisation has placed air pollution as the world's largest environmental health risk factor. There has been recent publicity about the role for diet and anti-oxidants in mitigating the effects of pollution, and this review assesses the evidence for alterations in diet, including vitamin supplementation in abrogating the effects of pollution on asthma and other chronic respiratory diseases. We found evidence to suggest that carotenoids, vitamin D and vitamin E help protect against pollution damage which can trigger asthma, COPD and lung cancer initiation. Vitamin C, curcumin, choline and omega-3 fatty acids may also play a role. The Mediterranean diet appears to be of benefit in patients with airways disease and there appears to be a beneficial effect in smokers however there is no direct evidence regarding protecting against air pollution. More studies investigating the effects of nutrition on rapidly rising air pollution are urgently required. However it is very difficult to design such studies due to the confounding factors of diet, obesity, co-morbid illness, medication and environmental exposure.

Role of lipid mediators and control of lymphocyte responses in type 2 immunopathology

Type 2 immunopathology is a cardinal feature of allergic diseases and involves cooperation between adaptive immunity and innate effector responses. Virtually all cell types relevant to this pathology generate leukotriene and/or prostaglandin mediators that derive from arachidonic acid, express receptors for such mediators, or both. Recent studies highlight prominent functions for these mediators in communication between the innate and adaptive immune systems, as well as amplification or suppression of type 2 effector responses. This review focuses on recent advances and insights, and highlights existing and potential therapeutic applications of drugs that target these mediators or their receptors, with a special emphasis on their regulation of the innate and adaptive lymphocytes relevant to type 2 immunopathology.

Obesogenic diets alter metabolism in mice

Obesity and accompanying metabolic disease is negatively correlated with lung health yet the exact mechanisms by which obesity affects the lung are not well characterized. Since obesity is associated with lung diseases as chronic bronchitis and asthma, we designed a series of experiments to measure changes in lung metabolism in mice fed obesogenic diets. Mice were fed either control or high fat/sugar diet (45%kcal fat/17%kcal sucrose), or very high fat diet (60%kcal fat/7% sucrose) for 150 days. We performed untargeted metabolomics by GC-TOFMS and HILIC-QTOFMS and lipidomics by RPLC-QTOFMS to reveal global changes in lung metabolism resulting from obesity and diet composition. From a total of 447 detected metabolites, we found 91 metabolite and lipid species significantly altered in mouse lung tissues upon dietary treatments. Significantly altered metabolites included complex lipids, free fatty acids, energy metabolites, amino acids and adenosine and NAD pathway members. While some metabolites were altered in both obese groups compared to control, others were different between obesogenic diet groups. Furthermore, a comparison of changes between lung, kidney and liver tissues indicated few metabolic changes were shared across organs, suggesting the lung is an independent metabolic organ. These results indicate obesity and diet composition have direct mechanistic effects on composition of the lung metabolome, which may contribute to disease progression by lung-specific pathways.

Polyunsaturated fatty acids in plasma at 8 years and subsequent allergic disease

BACKGROUND

Polyunsaturated fatty acids (PUFAs) are hypothesized to modulate the risk of allergic disease. However, evidence from previous studies is inconclusive, and limited longitudinal data exist using circulating biomarkers of PUFA intake and metabolism.

OBJECTIVE

We aimed to investigate associations between n-3 and n-6 PUFAs at age 8 years and asthma, rhinitis, and aeroallergen sensitization at age 16 years.

METHODS

Proportions of n-3 PUFAs (very long-chain n-3 [VLC n-3; sum of eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid] and α-linolenic acid) and n-6 PUFAs (linoleic acid and arachidonic acid [AA]) in blood samples at age 8 years were measured for 940 children from the prospective Swedish birth cohort BAMSE (Children, Allergy, Milieu, Stockholm, Epidemiology). Allergic disease phenotypes were defined by using questionnaires and IgE measures at the ages of 8 and 16 years. Logistic regression was used to examine potential associations.

RESULTS

A higher proportion of total VLC n-3 PUFAs in plasma at age 8 years was associated with a reduced risk of prevalent asthma, rhinitis, and aeroallergen sensitization at age 16 years and with incidence of asthma between 8 and 16 years (adjusted odds ratio, 0.67; 95% CI, 0.47-0.94). AA was associated with a reduced risk of asthma, aeroallergen sensitization, and allergic rhinitis. The findings were most evident for allergic phenotypes of asthma and rhinitis. Additionally, AA was associated with an increased probability of asthma and rhinitis remission between 8 and 16 years of age.

CONCLUSION

Higher proportions of certain VLC n-3 and very long-chain n-6 PUFAs in plasma phospholipids at age 8 years were associated with a reduced risk of allergic disease at age 16 years.

Anti-allergic Hydroxy Fatty Acids from Typhonium blumei Explored through ChemGPS-NP

Increasing prevalence of allergic diseases with an inadequate variety of treatment drives forward search for new alternative drugs. Fatty acids, abundant in nature, are regarded as important bioactive compounds and powerful nutrients playing an important role in lipid homeostasis and inflammation. Phytochemical study on Typhonium blumei Nicolson and Sivadasan (Araceae), a folk anti-cancer and anti-inflammatory medicine, yielded four oxygenated fatty acids, 12R-hydroxyoctadec-9Z,13E-dienoic acid methyl ester (1) and 10R-hydroxyoctadec-8E,12Z-dienoic acid methyl ester (2), 9R-hydroxy-10E-octadecenoic acid methyl ester (3), and 12R^*-hydroxy-10E-octadecenoic acid methyl ester (4). Isolated compounds were identified by spectroscopic methods along with GC-MS analysis. Isolated fatty acids together with a series of saturated, unsaturated and oxygenated fatty acids were evaluated for their anti-inflammatory and anti-allergic activities in vitro. Unsaturated (including docosahexaenoic and eicosapentaenoic acids) as well as hydroxylated unsaturated fatty acids exerted strong anti-inflammatory activity in superoxide anion generation (IC₅₀ 2.14-3.73 μM) and elastase release (IC₅₀ 1.26-4.57 μM) assays. On the other hand, in the anti-allergic assays, the unsaturated fatty acids were inactive, while hydroxylated fatty acids showed promising inhibitory activity in A23187- and antigen-induced degranulation assays (e.g., 9S-hydroxy-10E,12Z-octadecadienoic acid, IC₅₀ 92.4 and 49.7 μM, respectively). According to our results, the presence of a hydroxy group in the long chain did not influence the potent anti-inflammatory activity of free unsaturated acids. Nevertheless, hydroxylation of fatty acids (or their methyl esters) seems to be a key factor for the anti-allergic activity observed in the current study. Moreover, ChemGPS-NP was explored to predict the structure-activity relationship of fatty acids. The anti-allergic fatty acids formed different cluster distant from clinically used drugs. The bioactivity of T. blumei, which is historically utilized in folk medicine, might be related to the content of fatty acids and their metabolites.