Food restriction and fish oil suppress atherogenic risk factors in lupus-prone (NZB x NZW) F1 mice

Nutritional Approaches to Modulate Cardiovascular Disease Risk in Systemic Lupus Erythematosus: A Literature Review

Systemic lupus erythematosus (SLE) is a chronic pathology characterized by a bimodal mortality pattern attributed to clinical disease activity and cardiovascular disease (CVD). A complex interaction between traditional CVD risk factors such as obesity, dyslipidemia, smoking, insulin resistance, metabolic syndrome, and hypertension, as well as the presence of non-traditional CVD risk factors such as hyperhomocysteinemia, pro-inflammatory cytokines, and C-reactive protein levels, has been suggested as a cause of the high prevalence of CVD in SLE patients. On the other hand, environmental factors, such as nutritional status, could influence the disease's prognosis; several nutrients have immunomodulators, antioxidants, and anti-cardiometabolic risk properties which could reduce SLE severity and organ damage by decreasing the development of traditional and non-traditional CVD risk factors. Therefore, this critical literature review discusses the therapeutic potential of nutritional approaches that could modulate the development of the main comorbidities related to CVD risk in SLE patients.

Relationship of Excess Weight with Clinical Activity and Dietary Intake Deficiencies in Systemic Lupus Erythematosus Patients

Obesity and nutrients intake deficiencies may contribute to the clinical manifestations and inflammatory processes in systemic lupus erythematosus (SLE). The aim of this study was to assess the relationship between nutritional status and dietary intake with clinical variables in Mexican-mestizo SLE patients. A cross-sectional study was conducted in 130 female SLE patients, classified by the 1997 SLE American College of Rheumatology (ACR) criteria; the clinical activity was evaluated by the Mexican-Systemic Lupus Erythematosus-Disease Activity Index (Mex-SLEDAI); body mass index (BMI) by the World Health Organization (WHO) criteria; the energy calculation and nutritional intake were performed by Nutritionist Pro Diet software. SLE patients with excess weight (BMI > 25 kg/m²) showed a higher score of clinical activity (Mex-SLEDAI = 2; p = 0.003), higher clinical activity prevalence (40.9%; p = 0.039) and a significant association for high clinical activity (odds ratio (OR) = 2.52; 95% confidence interval (CI) = 1.08-5.9; p = 0.033), in comparison with patients without excess weight (BMI < 25 kg/m²). In particular, the excess weight increased the Mex-SLEDAI score (β coefficient = 1.82; R² = 0.05; p = 0.005). Also, the SLE patients presented a high prevalence (%) of deficient consumption (cut-off point: <67% of dietary adequacy) of vitamin E (100%), iodine (96%), omega 3 (93.44%), biotin (78%), vitamin K (73.33%), iron (67%), vitamin D (63.3%), potassium (59%), folic acid (56.67%), pantothenic acid (43.3%), vitamin A (41.67%) and zinc (32%). In conclusion, in SLE patients the excess weight was associated with increased clinical activity and to the presence of deficiencies in some essential nutrients ingested.

The Influence of Diet and Obesity on Gene Expression in SLE

This review provides an overview of the known effects of diet, obesity, and the intake of different nutrients on systemic lupus erythematosus (SLE). It summarizes and discusses the studies in rodents that identified how different diets can regulate gene expression in the disease, together with a description of the effects of diet on lupus patients’ inflammatory state and disease severity. The identification of selected dietary candidates that can modulate SLE onset and progression is analyzed in relation to possible targeted approaches that could ultimately ameliorate the management and prognosis of this disease.

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.

Meal frequency and timing in health and disease

Although major research efforts have focused on how specific components of foodstuffs affect health, relatively little is known about a more fundamental aspect of diet, the frequency and circadian timing of meals, and potential benefits of intermittent periods with no or very low energy intakes. The most common eating pattern in modern societies, three meals plus snacks every day, is abnormal from an evolutionary perspective. Emerging findings from studies of animal models and human subjects suggest that intermittent energy restriction periods of as little as 16 h can improve health indicators and counteract disease processes. The mechanisms involve a metabolic shift to fat metabolism and ketone production, and stimulation of adaptive cellular stress responses that prevent and repair molecular damage. As data on the optimal frequency and timing of meals crystalizes, it will be critical to develop strategies to incorporate those eating patterns into health care policy and practice, and the lifestyles of the population.

AMP activated protein kinase is indispensable for myocardial adaptation to caloric restriction in mice

Caloric restriction (CR) is a robust dietary intervention known to enhance cardiovascular health. AMP activated protein kinase (AMPK) has been suggested to mediate the cardioprotective effects of CR. However, this hypothesis remains to be tested by using definitive loss-of-function animal models. In the present study, we subjected AMPKα2 knockout (KO) mice and their wild type (WT) littermates to a CR regimen that reduces caloric intake by 20%–40% for 4 weeks. CR decreased body weight, heart weight and serum levels of insulin in both WT and KO mice to the same degree, indicating the effectiveness of the CR protocol. CR activated cardiac AMPK signaling in WT mice, but not in AMPKα2 KO mice. Correspondingly, AMPKα2 KO mice had markedly reduced cardiac function during CR as determined by echocardiography and hemodynamic measurements. The compromised cardiac function was associated with increased markers of oxidative stress, endoplasmic reticulum stress and myocyte apoptosis. Mechanistically, CR down-regulated the expression of ATP5g2, a subunit of mitochondrial ATP synthase, and reduced ATP content in AMPKα2 KO hearts, but not in WT hearts. In addition, CR accelerated cardiac autophagic flux in WT mice, but failed to do so in AMPKα2 KO mice. These results demonstrated that without AMPK, CR triggers adverse effects that can lead to cardiac dysfunction, suggesting that AMPK signaling pathway is indispensible for energy homeostasis and myocardial adaptation to CR, a dietary intervention that normally produces beneficial cardiac effects.

High dietary fat promotes visceral obesity and impaired endothelial function in female mice with systemic lupus erythematosus

BACKGROUND

Inflammation contributes to metabolic and cardiovascular disease. Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disorder that predominantly affects young women. Cardiovascular disease is a major cause of mortality in patients with SLE. We recently reported that a model of SLE (female New Zealand Black/White F1 [NZBWF1] mice) developed characteristics of the metabolic syndrome.

OBJECTIVES

In the present study, we tested the hypothesis that high dietary fat with SLE accelerated development of cardiovascular risk factors such as central obesity and vascular dysfunction.

METHODS

Twenty-four-week-old female SLE mice (NZBWF1) were fed either a control diet (SLE, 10% kcal) or a high-fat (HF) diet (SLE + HF, 45% kcal) for a total of 14 weeks.

RESULTS

Body weight was similar between SLE (42 [1] g, n = 5) and SLE + HF (45 [2] g, n = 6) mice, and weight gain was not different in the SLE + HF mice (+18.0 [3.0]%) compared with controls (+15.8 [3.6]%); food intake was not different (SLE, 2.2 [0.3] vs SLE + HF, 2.1 [0.2] g/24 hours). At the end of the experiment, 57% of the SLE + HF mice exhibited signs of albuminuria (>100 mg/dL) compared with only 20% of the control SLE mice. Endothelial-dependent relaxation in isolated carotid arteries was impaired in the SLE + HF group compared with that in the SLE group. Ovarian fat increased in SLE + HF mice (6.6 [0.5] g) compared with that in the control SLE mice (5.4 [0.1] g, P < 0.05), and liver weight decreased in SLE + HF (1.6 [0.1] g) mice compared with that in control mice (1.9 [0.1] g, P < 0.03).

CONCLUSIONS

These data suggest that dietary fat accelerates renal injury and peripheral vascular dysfunction and promotes visceral obesity in a disease model with chronic inflammation.

Caloric restriction mimetic 2-deoxyglucose antagonizes doxorubicin-induced cardiomyocyte death by multiple mechanisms

Caloric restriction (CR) is a dietary intervention known to enhance cardiovascular health. The glucose analog 2-deoxy-D-glucose (2-DG) mimics CR effects in several animal models. However, whether 2-DG is beneficial to the heart remains obscure. Here, we tested the ability of 2-DG to reduce cardiomyocyte death triggered by doxorubicin (DOX, 1 μm), an antitumor drug that can cause heart failure. Treatment of neonatal rat cardiomyocytes with 0.5 mm 2-DG dramatically suppressed DOX cytotoxicity as indicated by a decreased number of cells that stained positive for propidium iodide and reduced apoptotic markers. 2-DG decreased intracellular ATP levels by 17.9%, but it prevented DOX-induced severe depletion of ATP, which may contribute to 2-DG-mediated cytoprotection. Also, 2-DG increased the activity of AMP-activated protein kinase (AMPK). Blocking AMPK signaling with compound C or small interfering RNA-mediated knockdown of the catalytic subunit markedly attenuated the protective effects of 2-DG. Conversely, AMPK activation by pharmacological or genetic approach reduced DOX cardiotoxicity but did not produce additive effects when used together with 2-DG. In addition, 2-DG induced autophagy, a cellular degradation pathway whose activation could be either protective or detrimental depending on the context. Paradoxically, despite its ability to activate autophagy, 2-DG prevented DOX-induced detrimental autophagy. Together, these results suggest that the CR mimetic 2-DG can antagonize DOX-induced cardiomyocyte death, which is mediated through multiple mechanisms, including the preservation of ATP content, the activation of AMPK, and the inhibition of autophagy.

Caloric restriction and heart function: is there a sensible link?

Calorie restriction (CR) is defined as a reduction in calorie intake below the usual ad libitum intake without malnutrition. Ample of clinical and experimental evidence has demonstrated that CR is capable of retarding aging process and development of cardiovascular disease. Although suppression of reactive oxygen species production and inflammation plays a central role in the favorable cardiovascular effects of CR, the health benefit of CR is believed to be ultimately mediated through a cadre of biochemical and cellular adaptations including redox homeostasis, mitochondrial function, inflammation, apoptosis and autophagy. Despite the apparent beneficial cardiovascular effects of CR, implementation of CR in the health care management is still hampered by apparent applicability issues and health concerns. Here we briefly review the cardiac consequence of CR and discuss whether CR may represent a safe and effective strategy in the management of cardiovascular health.

Effects of energy restriction and fish oil supplementation on renal guanidino levels and antioxidant defences in aged lupus-prone B/W mice

Energy restriction (ER) and dietary fish oil (FO) are known to reduce the severity of glomerulonephritis and increase the lifespan of lupus-prone (NZB×NZW) F1(B/W) mice. In the present study, mice were fed eitherad libitumor energy-restricted (a 40 % lower energy intake than the dietad libitum), semi-purified diets containing 5 % maize oil or 5 % fish oil supplementation. To estimate the renal damage associated with oxidative stress, the total amounts of reactive oxygen species (ROS), cyclooxygenase-derived ROS and levels of guanidino compounds were measured. Additionally, we assessed the putative action of ER and FO on several key antioxidant enzymes measured in the kidney post-mitochondrial fraction. Results showed that the age-related increase in creatinine level was significantly reduced by ER and FO in old mice. In contrast, arginine and guanidino acetic acid levels showed a decrease with age but were increased by ER and FO. The GSH:GSSG ratio showed a significant decrease with age, whereas ER and FO feeding prevented the decrease. The age-related decrease in antioxidant scavenging superoxide dismutase, catalase and glutathione peroxidase activities were all reversed by ER and FO. The moderately decreased glutathione reductase and glutathione-S-transferase activities with age were significantly increased by ER and FO. Furthermore, the increased total ROS and cyclooxygenase-derived ROS levels were effectively reduced by ER and FO. In conclusion, our data strongly indicate that ER and FO maintain antioxidant status and GSH:GSSG ratio, thereby protecting against renal deterioration from oxidative insults during ageing.

Caloric restriction inhibits up-regulation of inflammatory cytokines and TNF-α, and activates IL-10 and haptoglobin in the plasma of streptozotocin-induced diabetic rats

Diabetes mellitus is a significant risk factor for cardiovascular diseases, and low-grade systemic inflammation, mediated by oxidative stress, may play a central role. Caloric restriction (CR) has been reported to be effective in reducing oxidative stress during diabetes and moderating the expression of some markers of inflammation that are up-regulated during aging. Forty male Wistar rats were randomly divided into four groups: nondiabetic feeding ad libitum and under CR, and diabetic feeding ad libitum and under CR. The animals were subjected to 30% CR and ad libitum feeding for 9 weeks before the induction of diabetes by intraperitoneal injection with 35 mg/kg body weight streptozotocin. The inflammatory cytokines [interleukin (IL)-1beta, IL-4 and IL-6] and tumor necrosis factor alpha up-regulated in diabetes were found to be significantly depressed by CR, whereas the antiinflammatory mediators, haptoglobin and IL-10 levels, were increased. These results indicated that CR could prevent diabetic complications through suppression of inflammatory responses.

Anti-inflammatory action of dietary fish oil and calorie restriction

Inflammation, inflammatory mediators, cyclooxygenase (COX)-2, and inducible nitric oxide (iNOS) are all influenced by age-related oxidative status. To investigate the effect of dietary fish oil (FO) and calorie restriction (CR) on oxidative stress-related inflammatory status with age, (NZB/NZW) F1 (B/W) mice were fed for 4 and 9 months either ad libitum or calorie-restricted (60% of ad libitum intake) diets containing 5% corn oil or 5% FO. We measured several key oxidative and inflammatory markers: TBARS, xanthine oxidase (XOD)-derived superoxide generation, and PGE2 and LTB4 production. Expressions of renal COX-1, COX-2, and iNOS mRNA were analyzed by RT-PCR; additionally, COX-2 protein was estimated by Western-blot method. Results show that FO intake and CR individually and together suppressed age-related increases in lipid peroxidation and superoxide generation. The inhibitory effects of dietary FO and CR were also found for iNOS expression, COX-2 expression, which subsequently led to the suppression of PGE2 and LTB4. We conclude that the beneficial effects of FO feeding and CR are synergistic in ameliorating the age-related nephritis of B/W mice by suppressing COX-2 and iNOS, reactive species generation, and pro-inflammatory mediators.

Inhibition of osteoporosis in autoimmune disease prone MRL/Mpj-Fas(lpr) mice by N-3 fatty acids

OBJECTIVE

Rheumatoid arthritis (RA) is a systemic autoimmune inflammatory disease involving the breakdown of cartilage and juxta-articular bone, which is often accompanied by decreased bone mineral density (BMD) and increased risk of fracture. Anti-inflammatory omega-3 fatty acids may prevent arthritis and bone loss in MRL/lpr mice model of arthritis and in humans.

METHODS

In this study, the effect of long term feeding of 10% dietary n-3 (fish oil (FO)) and n-6 (corn oil (CO)) fatty acids begun at 6 weeks of age on bone mineral density (BMD) in different bone regions in an MRL/lpr female mouse model of RA was measured at 6, 9, and 12 months of age by dual energy x-ray absorptiometry (DEXA). After sacrificing the mice at 12 months of age, antioxidant enzyme activities were measured in spleen, mRNA for receptor activator of NF-kappaB ligand (RANKL) and osteoprotegerin (OPG) was measured by RT-PCR in lymph nodes, and synovitis was measured in leg joints.

RESULTS

At 6, 9 and 12 months of age, BMD was significantly higher (p < 0.05) in distal femur, proximal tibia, and lumbar spine of FO fed mice than those of CO fed mice. Spleen catalase (CAT) and superoxide dismutase (SOD) activities were also significantly higher (p < 0.01) in FO fed mice than in CO fed mice. Histology of knee joints revealed mild synovitis in CO fed mice, which was not present in FO fed mice. RT-PCR analysis of lymph nodes revealed decreased RANKL mRNA (p < 0.001) expression and enhanced OPG mRNA expression (p < 0.01) in FO fed mice compared to CO fed mice.

CONCLUSIONS

These results suggest beneficial effects of long-term FO feeding in maintaining higher BMD and lower synovitis in this mouse model. These beneficial effects may be due, in part, to increased activity of antioxidant enzymes, decreased expression of RANKL, and increased expression of OPG in FO fed mice thereby altering the RANKL/OPG ratio. These significant beneficial effects on BMD suggest that FO may serve as an effective dietary supplement to prevent BMD loss in patients with RA.

Diet manipulation and prevention of aging, cancer and autoimmune disease

PURPOSE OF REVIEW

Dietary supplementation and other dietary regimens have become increasingly popular in the US population. Information regarding how different dietary constituents interact when consumed simultaneously is needed. This review examines the recent literature on how different dietary constituents may interact physiologically when consumed in combination. Furthermore, the potential human relevance of calorie restriction and nonclassical function of vitamin E is discussed.

RECENT FINDINGS

Long-term calorie restriction in monkeys has shown similar beneficial effects as has been shown in rodents. Limited calorie restriction studies in humans have shown promise in reducing the incidence of heart disease and breast cancer. The combination of calorie restriction and omega-3 fatty acids may be a more potent antiinflammatory diet than either regimen alone. The type of fiber that is most protective against colon cancer may be dependent on the type of dietary fat consumed simultaneously. Vitamin E derivatives that possess no antioxidant activity may be potent inhibitors of cancer, but not normal, cell growth.

SUMMARY

Dietary modification has shown its greatest beneficial effect when started prior to or immediately after the onset of disease. Also, understanding how the subtypes or isoforms of nutrients function is important since their physiological effects may be drastically different. It is important to understand the entire dietary profile of an individual when making dietary recommendations because one nutrient, or dietary ingredient, may enhance or cancel out the beneficial effects of another dietary ingredient.

Age associated alterations in costimulatory and adhesion molecule expression in lupus-prone mice are attenuated by food restriction with n-6 and n-3 fatty acids

Costimulatory and adhesion molecules are known to play a major role in the pathogenesis of systemic lupus erythematosus. Since fish oil and calorie restriction have been reported to attenuate the development of disease in lupus prone (NZBxNZW)F1 mice, the objective of this study was to assess the expression of these key inflammatory molecules in these mice fed diets differing in n-6 and n-3 fatty acid content and fed either food restricted or ad libitum. Age-associated increases in the expression of CD28, ICAM-1, and PGP-1 molecules that are involved in the recruitment of inflamed lymphocytes into the kidney were attenuated in mice restricted in food intake. The increase in costimulatory (CD80 and CD86) and adhesion (ICAM-1, PGP-1, LFA-1, and Mac-1) in peripheral blood mononuclear cells was also attenuated by food restriction and to a lesser extent by fish oil alone. Interestingly, amelioration of lupus (laminin expression and proteinuria) correlated with the above beneficial effects and could be seen even in 24-month-old mice. In summary, food restriction and fish oil delay the onset of lupus disease and increase life span in B/W mice by prolonging the maintenance of a youthful immune phenotype.

Atorvastatin inhibits autoreactive B cell activation and delays lupus development in New Zealand black/white F1 mice

Systemic lupus erythematosus is a multisystem autoimmune disease characterized by a wide range of immunological abnormalities that underlie the loss of tolerance. In this study we show that administration of atorvastatin to lupus-prone NZB/W F(1) mice resulted in a significant reduction in serum IgG anti-dsDNA Abs and decreased proteinuria. Histologically, the treatment was associated with reduced glomerular Ig deposition and less glomerular injury. Disease improvement was paralleled by decreased expression of MHC class II on monocytes and B lymphocytes and reduced expression of CD80 and CD86 on B lymphocytes. Consequent upon this inhibition of Ag presentation, T cell proliferation was strongly impaired by atorvastatin in vitro and in vivo. A significant decrease in MHC class II expression was also observed in the target organ of lupus disease (i.e., the glomerulus). Serum cholesterol in atorvastatin-treated lupus mice fell to the level found in young NZB/W mice before disease onset. This is the first demonstration that atorvastatin can delay the progression of a spontaneous autoimmune disease and may specifically benefit patients with systemic lupus erythematosus.

Regulation of immune function by calorie restriction and cyclophosphamide treatment in lupus-prone NZB/NZW F1 mice

We compared the effects of calorie restriction (CR) and cyclophosphamide (CTX) on the progression of lupus nephritis and immunological changes in NZB/NZW F1 mice. Ad libitum (AL)/CTX and CR delayed onset of proteinuria and significantly decreased serum levels of anti-dsDNA, anti-histone, and circulating immune complex antibodies. CTX and CR prevented the increase in and activation of B cells, the decline in CD8(+) T cells, and maintained a higher proportion of naïve CD4(+) and CD8(+) cells. MHC class I antigen and LFA-1 expression on CD8(+) T cells and MHC class II antigen on B cells were also decreased. AL/CTX and CR prevented the increase in production of IL-10 and up-regulated IL-2 production in T cells ex vivo. We concluded that both CR and CTX can delay the onset of autoimmune disease, in part by maintaining higher numbers of naïve T cells and the immune responsiveness of T cells and decreasing the proportion of B cells.