Dietary fat affects lipids and anti-cardiolipin antibody levels in autoimmune-prone NZB/W F1 mice

Relationship between serum levels of immunoglobulins and metabolic syndrome in an adult population: A population study from the TCLSIH cohort study

BACKGROUND AND AIMS

Metabolic syndrome (MetS) is a combination of metabolic disorders that increase the risk of developing cardiovascular disease, and inflammation is considered as a pathological basis for MetS. Immunoglobulins (Igs) are the major secretory products of the adaptive immune system. However, no large-scale population study has focused on a possible relationship between Igs and MetS. We designed a cross-sectional study to investigate the relationship between Igs and prevalence of MetS in a large-scale adult population.

METHODS AND RESULTS

A total of 10,289 participants were recruited among residents in Tianjin, China. Metabolic syndrome was defined in accordance with the criteria of the American Heart Association scientific statements of 2009. Serum levels of Igs were determined by immunonephelometry. Multiple logistic regression models were used to assess the relationship between the quintiles of serum levels of Igs and the prevalence of MetS. The overall prevalence of MetS was 36.1%. The mean (standard deviation) values of Igs (IgG, IgE, IgM, and IgA) were 1205.7 (249.3) mg/dL, 93.1 (238.9) IU/mL, 105.7 (57.3) mg/dL, and 236.2 (97.6) mg/dL, respectively. The adjusted odds ratios (95% confidence interval) of MetS for the highest quintile of Igs (IgG, IgE, IgM, and IgA), when compared to the lowest quintile, were 0.81 (0.70, 0.95), 0.97 (0.83, 1.12), 1.13 (0.97, 1.33), and 1.52 (1.30, 1.77), respectively.

CONCLUSIONS

This study demonstrated that decreased IgG and increased IgA are independently related to a higher prevalence of MetS. The results indicate that the Igs might be useful predictive factors for MetS in the general adult population.

Role of Fatty Acids Intake in Generalized Vitiligo

Background

Previous studies indicated the effect of fat on autoimmune diseases. The present study was aimed to investigate the association between fat intake and vitiligo.

Methods

This case-control study was conducted in the Skin and Leishmania Research Center, Isfahan University of Medical Sciences, Isfahan, Iran. Intakes of fatty acids were examined for their relation to risk of vitiligo among 100 cases and 110 controls. We included patients who suffered from generalized or localized vitiligo for <5 years that was approved by a dermatologist via the Vitiligo European Task Force criteria and the vitiligo area scoring index. Fat intake was assessed through individual interviews by a standardized food frequency questionnaire.

Results

Vitiligo group consumed more saturated fatty acid (SFA) and less eicosapentaenoic acid and docosahexaenoic acid than control group, while other fatty acids were not significantly different among two groups (P > 0.05). Crude analysis showed that total fat (odds ratio [OR] = 3.33, 95% confidence interval [CI]: 1.46-7.58) and SFA (OR = 2.22, 95% CI: 1.04-4.90) intakes were associated with an increased risk of vitiligo (for highest quartile vs. lowest quartile). Results demonstrated a decrease in the risk of vitiligo for those within the highest quartile of monounsaturated fatty acids intake (OR = 0.41, 95% CI: 0.18-0.92). However, this relationship disappeared after adjustment for confounders as energy, age, sex, and body mass index, except for total fat (OR = 2.84, 95% CI: 1.63-5.44). Crude and adjusted analyses for polyunsaturated fatty acids and cholesterol intake were not statistically significant.

Conclusions

Total-fat content of the diet had more impressive role than the specific subclasses of fats on the incidence risk of vitiligo. High-fat diet escalated the vitiligo risk. Regarding the role of fats on skin autoimmune diseases especially vitiligo, future studies are crucial.

An update on diet and nutritional factors in systemic lupus erythematosus management

Systemic lupus erythematosus (SLE) is a chronic inflammatory and autoimmune disease characterised by multiple organ involvement and a large number of complications. SLE management remains complicated owing to the biological heterogeneity between patients and the lack of safe and specific targeted therapies. There is evidence that dietary factors can contribute to the geoepidemiology of autoimmune diseases such as SLE. Thus, diet therapy could be a promising approach in SLE owing to both its potential prophylactic effects, without the side effects of classical pharmacology, and its contribution to reducing co-morbidities and improving quality of life in patients with SLE. However, the question arises as to whether nutrients could ameliorate or exacerbate SLE and how they could modulate inflammation and immune function at a molecular level. The present review summarises preclinical and clinical experiences to provide the reader with an update of the positive and negative aspects of macro- and micronutrients and other nutritional factors, including dietary phenols, on SLE, focusing on the mechanisms of action involved.

Dietary factors regulate cytokines in murine models of systemic lupus erythematosus

Cytokines play the active roles in the pathogenesis of systemic lupus erythematosus (SLE) and contribute significantly to the immune imbalance in this disease. Conservative therapeutic approaches, such as dietary modifications have been shown to have some beneficial impact on the disease activity of the SLE. Over the past years, accumulating evidences have supported a major role for specific dietary factors, including calorie restriction, n-3/n-6 fatty acids, vitamin A, vitamin D, vitamin E, phytoestrogens or herbal medicine in the regulation of cytokines involved in SLE development. Although there are many reviews that discuss the issue of nutrition and immunity, there are relatively few articles that focus on the regulation of cytokines by dietary factors. This concise review will summarize those animal studies that investigated not only the outcome of autoantibody production and proteinuria, but also cytokines production. However, the field of dietary factors in the immunomodulation of SLE is still in its infancy. More clinical studies are needed to confirm the preliminary results and advance the knowledge in this field. Lifestyle modification and adjustments in diet are important and encouraged to be suggested as an adjuvant therapy for SLE.

The interplay of inflammation and cardiovascular disease in systemic lupus erythematosus

Patients with systemic lupus erythematosus have up to a 50-fold increased risk of developing atherosclerotic cardiovascular disease. Recent advances in the etiology of vascular damage in this disease stress the interplay of lupus-specific inflammatory factors with traditional cardiac risk factors, leading to increased endothelial damage. This review analyzes the putative role that immune dysregulation and lupus-specific factors may play in the pathogenesis of premature vascular damage in this disease. The potential role of various cytokines, in particular type I interferons, in the development of accelerated atherosclerosis is examined. Potential therapeutic targets are discussed.

Accelerated atherosclerosis is independent of feeding high fat diet in systemic lupus erythematosus-susceptible LDLr(-/-) mice

Individuals suffering from systemic lupus erythematosus (SLE) are predisposed to accelerate cardiovascular disease. Our laboratory has recently developed an animal model of SLE-accelerated atherosclerosis. We have shown that, following 8 weeks feeding high fat Western diet, radiation chimeras consisting of SLE-derived haematopoietic cells transferred to low-density lipoprotein (LDL)r(-/-) mice (LDLr.Sle) have increased atherosclerosis compared with C57Bl/6 bone marrow recipients (LDLr.B6). However, this feeding regimen resulted in significant mortality in SLE-susceptible mice compared with controls with surviving animals having extremely elevated serum cholesterol (>500 mg/dL) and increased serum markers of kidney pathology. To test the hypothesis that SLE-associated autoimmune dysregulation can exacerbate atherosclerosis under more mild serum cholesterol conditions (approximately 200 mg/dL), we examined SLE and lesion development in radiation chimeras fed either a normal chow or high fat Western diet for 8 weeks. High fat fed LDLr.Sle mice exhibited increased mortality and were significantly more hypertensive. LDLr.Sle mice had greater titres of antibodies against dsDNA, oxLDL and phospholipid compared with controls. Lupus-susceptibility increased the atherosclerotic lesions and the percentage of CD4(+) T cells in the lesions of proximal aortas, independent of diet. These data show that increased dyslipidemia resulting from high-fat feeding can exacerbate autoimmunity and associated vascular complications. Conversely, they also show that autoimmune dysregulation can accelerate atherosclerosis in LDLr-deficient animals independent of feeding high fat diet. Collectively this study provides additional evidence that the accelerated atherosclerosis observed in SLE is autoimmune associated.

The ethyl acetate extract of alfalfa sprout ameliorates disease severity of autoimmune-prone MRL-lpr/lpr mice

Previous study showed that soy isoflavone supplement alleviates disease severity in autoimmune-prone mice. As the ethyl acetate extract of alfalfa sprout (AS) has selective oestrogenic and anti-inflammatory activity, this study evaluated the effects of alfalfa sprout ethyl acetate extract (ASEA) on disease severity of systemic lupus erythematosus, using autoimmune-prone female MRL- lpr/lpr mice. In Experiment 1, five groups of 12-week-old female mice were per oral treated with vehicle (control), lyophilized AS (550 mg wt/kg BW), ASEA (ASEA, 25 mg/kg BW), coumestrol (CUM, 0.075 mg/kg BW) and tamoxifen (TAM, 0.375 mg/kg BW) as the positive control. The onset of proteinuria was delayed, and the life span was significantly longer in the ASEA and TAM groups but neither in the AS nor in the CUM groups, compared to the control. To examine the changes in the immunological parameters related to disease process, three more groups of MRL- lpr/lpr female mice (control, ASEA and TAM) were fed in a similar manner for 6 weeks in the Experiment 2. Flow cytometric analysis of splenocytes showed a significantly lower percentage of activated T cells in the ASEA and TAM groups. The ex-vivo interferon-γ and interleukin (IL)-4 production from splenocytes and tumour necrosis factor-α and IL-1β production from peritoneal exudate cells were also significantly lower in the ASEA group compared with the control. The ASEA group also had less severe glomerulonephritis. Thus, ASEA attenuated cytokine and inflammatory responses of self-reactive lymphocytes, decreased the disease severity, increased survival and life span of the autoimmune-prone MRL- lpr/lpr mice, suggesting a potential of ASEA in the treatment of autoimmune diseases.

Opposite effects of low and high dose supplementation of vitamin E on survival of MRL/lpr mice

OBJECTIVE

The purpose of this study is to investigate the effects of vitamin E supplementation on the autoimmune disease course in MRL/lymphoproliferative mice.

METHODS

Three-month-old MRL/lymphoproliferative lpr female mice were fed an AIN-76 diet containing 50 mg/kg (control), 250 mg/kg (E5), 375 mg/kg (E7.5), or 500 mg/kg (E10) all-rac-alpha-tocopheryl acetate. Eight mice per group were killed for analysis after two months of experimental diets, and the rest of the mice were followed up to observe their proteinuria levels and life span.

RESULTS

The data suggest that the life span of the E5 group was longer than the E10 group. Though alpha-tocopherol content in the plasma, liver, and kidneys increased in the mice fed the diet supplemented with vitamin E, the thiobarbituric acid reactive substance values in the liver and kidneys among these groups were not significantly different. IgM anti-ds-DNA and anticardiolipin antibodies were significantly higher in the E10 group than in those of the other groups. Phytohemagglutinin-stimulated interleukin (IL)-2 secretion was significantly lower, but concanavalinA-stimulated IL-4 and IL-10 production was significantly higher in the E10 group compared with the control group. The in vitro study also showed decreased IL-2 secretion and messenger RNA expression in phytohemagglutinin-stimulated splenocytes cultured in medium supplemented with high doses of vitamin E, but increased IL-2 with low doses of vitamin E.

CONCLUSIONS

Our data suggest that low and high dose supplementation of vitamin E has the opposite effect on the survival of MRL/lpr mice. The inhibitory effect of Th1 from high vitamin E content may not be beneficial for those suffering from Th2 prone autoimmune diseases, such as systemic lupus erythematosus.

The effects of vitamin E supplementation on autoimmune-prone New Zealand black x New Zealand white F1 mice fed an oxidised oil diet

The purpose of the present study was to investigate the effect of vitamin E supplementation on autoimmune disease in New Zealand blackxNew Zealand white F1 (NZB/W F1) female mice fed an oxidised oil diet. First, 5-month-old mice were fed an AIN-76 diet containing either 150 g fresh soyabean oil/kg (15S), 50 g fresh soyabean oil/kg + 100 g oxidised frying oil/kg (5S10F) or 5S10F supplemented with all-rac-alpha-tocopheryl acetate at 275 mg/kg diet level (5S10F5E) or 550 mg/kg (5S10F10E), respectively, in experiment 1. The results showed that mice fed the 5S10F10E diet had a lower anti-double-stranded DNA IgG antibody level and a longer lifespan than those fed the 15S and 5S10F diets. Therefore, the 5S10F and 5S10F10E treatments were repeated in experiment 2 for further analysis. The results showed that vitamin E supplementation in the oxidised oil significantly decreased thiobarbituric acid-reactive substance values in the kidney and spleen of NZB/W F1 mice. Interferon-gamma and IL-6 production by mitogen-stimulated splenocytes decreased in mice fed the 5S10F10E diet, whereas the secretion of IL-2 and IL-10 was not affected. The percentage of T-cells was significantly higher and that of MHC class II-bearing cells was lower in the spleens of the 5S10F10E group. The 5S10F10E group had a significantly higher linoleic acid (18 : 2n-6) composition than the 5S10F diet group. Therefore, vitamin E supplementation in oxidised oil might decrease oxidative stress, anti-double-stranded DNA IgG antibody, regulate cytokines and lymphocyte subsets, and subsequently alleviate the severity of autoimmune disease such as systemic lupus erythematosus under oxidative stress.

Fatty acids, the immune response, and autoimmunity: a question of n-6 essentiality and the balance between n-6 and n-3

The essentiality of n-6 polyunsaturated fatty acids (PUFA) is described in relation to a thymus/thymocyte accretion of arachidonic acid (20:4n-6, AA) in early development, and the high requirement of lymphoid and other cells of the immune system for AA and linoleic acid (1 8:2n-6, LA) for membrane phospholipids. Low n-6 PUFA intakes enhance whereas high intakes decrease certain immune functions. Evidence from in vitro and in vivo studies for a role of AA metabolites in immune cell development and functions shows that they can limit or regulate cellular immune reactions and can induce deviation toward a T helper (Th)2-like immune response. In contrast to the effects of the oxidative metabolites of AA, the longer-chain n-6 PUFA produced by gamma-linolenic acid (18:3n-6, GLA) feeding decreases the Th2 cytokine and immunoglobulin (Ig)G1 antibody response. The n-6 PUFA, GLA, dihomo-gamma-linolenic acid (20:3n-6, DHLA) and AA, and certain oxidative metabolites of AA can also induce T-regulatory cell activity, e.g., transforming growth factor (TGF)-beta-producing T cells; GLA feeding studies also demonstrate reduced proinflammatory interleukin (IL)-1 and tumor necrosis factor (TNF)-alpha production. Low intakes of long-chain n-3 fatty acids (fish oils) enhance certain immune functions, whereas high intakes are inhibitory on a wide range of functions, e.g., antigen presentation, adhesion molecule expression, Th1 and Th2 responses, proinflammatory cytokine and eicosanoid production, and they induce lymphocyte apoptosis. Vitamin E has a demonstrable critical role in long-chain n-3 PUFA interactions with immune functions, often reversing the effects of fish oil. The effect of dietary fatty acids on animal autoimmune disease models depends on both the autoimmune model and the amount and type of fatty acids fed. Diets low in fat, essential fatty acid deficient (EFAD), or high in long-chain n-3 PUFA from fish oils increase survival and reduce disease severity in spontaneous autoantibody-mediated disease, whereas high-fat LA-rich diets increase disease severity. In experimentally induced T cell-mediated autoimmune disease, EFAD diets or diets supplemented with long-chain n-3 PUFA augment disease, whereas n-6 PUFA prevent or reduce the severity. In contrast, in both T cell- and antibody-mediated autoimmune disease, the desaturated/elongated metabolites of LA are protective. PUFA of both the n-6 and n-3 families are clinically useful in human autoimmune-inflammatory disorders, but the precise mechanisms by which these fatty acids exert their clinical effects are not well understood. Finally, the view that all n-6 PUFA are proinflammatory requires revision, in part, and their essential regulatory and developmental role in the immune system warrants appreciation.

Diet and lupus

The effect of dietary modifications has been extensively studied in lupus animal models. Calorie, protein, and especially fat restriction, caused a significant reduction in immune-complex deposition in the kidney, reduced proteinuria and prolongation of the mice's life span. The addition of polyunsaturated fatty acids (PUFAs), such as fish oil or linseed oil, was also related to decreased mice morbidity and mortality in animal models of lupus and of antiphospholipid syndrome. PUFAs such as eicosapetaenoic acid (EPA) and docosahexaenoic acid (DHA) competitively inhibit arachidonic acid with a resultant decrease in inflammatory eicosanoids and cytokines. Human studies support the effect of a PUFAs-enriched diet, both scrologically and clinically. Large scale clinical studies are needed to confirm the primary results.

Dietary n-6 and n-3 fatty acids in immunity and autoimmune disease

Clearly there is much evidence to show that under well-controlled laboratory and dietary conditions fatty acid intake can have profound effects on animal models of autoimmune disease. Studies in human autoimmune disease have been less dramatic; however, human trials have been subject to uncontrolled dietary and genetic backgrounds, infection and other environmental influences, and basic trial designs have been inadequate. The impact of dietary fatty acids on animal autoimmune disease models appears to depend on the animal model and the type and amount of fatty acids fed. Diets low in fat, essential fatty acid-deficient, or high in n-3 fatty acids from fish oils increase the survival and reduce disease severity in spontaneous autoantibody-mediated disease, whilst linoleic acid-rich diets appear to increase disease severity. In experimentally-induced T-cell-mediated autoimmune disease, essential fatty acid-deficient diets or diets supplemented with n-3 fatty acids appear to augment disease, whereas n-6 fatty acids prevent or reduce the severity. In contrast, in both T-cell and antibody-mediated auto-immune disease the desaturated and elongated metabolites of linoleic acid are protective. Suppression of autoantibody and T lymphocyte proliferation, apoptosis of autoreactive lymphocytes, and reduced pro-inflammatory cytokine production by high-dose fish oils are all likely mechanisms by which n-3 fatty acids ameliorate autoimmune disease. However, these could be undesirable long-term effects of high-dose fish oil which may compromise host immunity. The protective mechanism(s) of n-6 fatty acids in T-cell- mediated autoimmune disease are less clear, but may include dihomo-gamma-linolenic acid- and arachidonic acid-sensitive immunoregulatory circuits such as Th1 responses, TGF beta 1-mediated effects and Th3-like responses. It is often claimed that n-6 fatty acids promote autoimmune and inflammatory disease based on results obtained with linoleic acid only. It should be appreciated that linoleic acid does not reflect the functions of dihomo-gamma-linolenic and arachidonic acid, and that the endogenous rate of conversion of linoleic to arachidonic acid is slow (Hassam et al. 1975, 1977; Phylactos et al. 1994; Harbige et al. 1995). In addition to effects of dietary fatty acids on immunoregulation, inflammation as a consequence of immune activation in autoimmune disease may also be an important mechanism of action whereby dietary fatty acids modulate disease activity. In conclusion, regulation of gene expression, signal transduction pathways, production of eicosanoids and cytokines, and the action of antioxidant enzymes are all mechanisms by which dietary n-6 and n-3 fatty acids may exert effects on the immune system and autoimmune disease. Probably the most significant of these mechanisms in relation to our current understanding of immunoregulation and inflammation would appear to be via fatty acid effects on cytokines. The amount, type and balance of dietary fatty acids and associated antioxidant nutrients appear to impact on the immune system to produce immune-deviation or immunosuppressive effects, and to reduce immune-mediated inflammation which will in turn affect the susceptibility to, or severity of, autoimmune disease.