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

Life factors acting on systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a highly heterogeneous autoimmune disease that primarily affects women. Currently, in the search for the mechanisms of SLE pathogenesis, the association of lifestyle factors such as diet, cigarette smoking, ultraviolet radiation exposure, alcohol and caffeine-rich beverage consumption with SLE susceptibility has been systematically investigated. The cellular and molecular mechanisms mediating lifestyle effects on SLE occurrence, including interactions between genetic risk loci and environment, epigenetic changes, immune dysfunction, hyper-inflammatory response, and cytotoxicity, have been proposed. In the present review of the reports published in reputable peer-reviewed journals and government websites, we consider the current knowledge about the relationships between lifestyle factors and SLE incidence and outline directions of future research in this area. Formulation of practical measures with regard to the lifestyle in the future will benefit SLE patients and may provide potential therapy strategies.

Immunomodulatory Effects of Diet and Nutrients in Systemic Lupus Erythematosus (SLE): A Systematic Review

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multiple organ involvement, including the skin, joints, kidneys, lungs, central nervous system and the haematopoietic system, with a large number of complications. Despite years of study, the etiology of SLE remains unclear; thus, safe and specifically targeted therapies are lacking. In the last 20 years, researchers have explored the potential of nutritional factors on SLE and have suggested complementary treatment options through diet. This study systematically reviews and evaluates the clinical and preclinical scientific evidence of diet and dietary supplementation that either alleviate or exacerbate the symptoms of SLE. For this review, a systematic literature search was conducted using PubMed, Scopus and Google Scholar databases only for articles written in the English language. Based on the currently published literature, it was observed that a low-calorie and low-protein diet with high contents of fiber, polyunsaturated fatty acids, vitamins, minerals and polyphenols contain sufficient potential macronutrients and micronutrients to regulate the activity of the overall disease by modulating the inflammation and immune functions of SLE.

Dietary Docosahexaenoic Acid Prevents Silica-Induced Development of Pulmonary Ectopic Germinal Centers and Glomerulonephritis in the Lupus-Prone NZBWF1 Mouse

Ectopic lymphoid structures (ELS) consist of B-cell and T-cell aggregates that are initiated de novo in inflamed tissues outside of secondary lymphoid organs. When organized within follicular dendritic cell (FDC) networks, ELS contain functional germinal centers that can yield autoantibody-secreting plasma cells and promote autoimmune disease. Intranasal instillation of lupus-prone mice with crystalline silica (cSiO₂), a respirable particle linked to human lupus, triggers ELS formation in the lung, systemic autoantibodies, and early onset of glomerulonephritis. Here we tested the hypothesis that consumption of docosahexaenoic acid (DHA), an ω-3 polyunsaturated fatty acid with anti-inflammatory properties, influences the temporal profile of cSiO₂-induced pulmonary ectopic germinal center formation and development of glomerulonephritis. Female NZBWF1 mice (6-wk old) were fed purified isocaloric diets supplemented with 0, 4, or 10 g/kg DHA - calorically equivalent to 0, 2, or 5 g DHA per day consumption by humans, respectively. Beginning at age 8 wk, mice were intranasally instilled with 1 mg cSiO₂, or saline vehicle alone, once per wk, for 4 wk. Cohorts were sacrificed 1, 5, 9, or 13 wk post-instillation (PI) of the last cSiO₂ dose, and lung and kidney lesions were investigated by histopathology. Tissue fatty acid analyses confirmed uniform dose-dependent DHA incorporation across all cohorts. As early as 1 wk PI, inflammation comprising of B (CD45R⁺) and T (CD3⁺) cell accumulation was observed in lungs of cSiO₂-treated mice compared to vehicle controls; these responses intensified over time. Marked follicular dendritic cell (FDC; CD21⁺/CD35⁺) networking appeared at 9 and 13 wk PI. IgG⁺ plasma cells suggestive of mature germinal centers were evident at 13 wk. DHA supplementation dramatically suppressed cSiO₂-triggered B-cell, T-cell, FDC, and IgG⁺ plasma cell appearance in the lungs as well as anti-dsDNA IgG in bronchial lavage fluid and plasma over the course of the experiment. cSiO₂ induced glomerulonephritis with concomitant B-cell accumulation in the renal cortex at 13 wk PI but this response was abrogated by DHA feeding. Taken together, realistic dietary DHA supplementation prevented initiation and/or progression of ectopic lymphoid neogenesis, germinal center development, systemic autoantibody elevation, and resultant glomerulonephritis in this unique preclinical model of environment-triggered lupus.

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.

Biomarkers of skin aging

Aging is a complex process not only influenced by inherited but also by several environmental factors. It is characterized by a progressive loss of function in multiple tissues, which leads to an increased probability of death. On the other hand, several morphological and histological changes are registered in aged skin that is mostly dependent on the cumulative exposure in environmental aging promoters, such as ultraviolet radiation. Understanding of individual pathogenesis and introduction of preventive measurements require objective assessment, i.e., the administration of biomarkers. Because of the complexity of skin aging, the exact definition of biomarkers is a major research challenge. In this article, we summarize the basic knowledge involving skin aging and its biomarkers.

Placebo-controlled randomized clinical trial of fish oil's impact on fatigue, quality of life, and disease activity in Systemic Lupus Erythematosus

Introduction

A recent metabolomic screen of sera from patients with Systemic Lupus Erythematosus (SLE) found reduction of antioxidants and substrates for energy generation. These metabolic alterations may underlie one of the most common features of SLE - fatigue. The metabolomic studies also noted reduced omega-3 fatty acids, which are powerful anti- oxidants. This deficiency may be causally related to oxidative stress, inflammation, disease activity, and fatigue in SLE. Supplementation of omega-3 fatty acids using fish oil in SLE has been shown to reduce oxidative stress in other studies. The objective of this study is to evaluate the effect of fish oil supplementation on clinical measures of fatigue, quality of life, and disease activity as part of a randomized clinical trial.

Methods

Fifty SLE patients recruited in outpatient clinics were randomized 1:1 to fish oil supplementation or olive oil placebo, and blinded to their treatment group. At baseline and after 6 months of treatment, RAND Short Form-36 (RAND SF-36), Fatigue Severity Scale (FSS), SLE Disease Activity Index (SLEDAI), and Physician Global Assessment (PGA) were completed; serum was also collected for soluble mediator analysis.

Results

Thirty-two patients completed the study. PGA improved significantly in the fish oil group compared with the placebo group (p = 0.015). The RAND SF-36 Energy/fatigue and Emotional well-being scores demonstrated improvement trends (p = 0.092 and 0.070). No clear difference was seen in FSS and SLEDAI (p = 0.350 and p = 0.417). Erythrocyte sedimentation rate and serum IL-12 were reduced (p = 0.008 and p = 0.058); while serum IL-13 was increased by fish oil supplementation (p = 0.033).

Conclusions

In this randomized, placebo-controlled 6-month trial, SLE patients randomized to fish oil supplementation demonstrated improvement in their PGA, RAND SF-36, and some circulating inflammatory markers.

Trial registration

ClinicalTrials.gov Identifier: NCT02021513 (registered 13 December 2013).

Ameliorative effects of phycocyanin against gibberellic acid induced hepatotoxicity

Gibberellic acid (GA3) was used extensively unaware in agriculture in spite of its dangerous effects on human health. The current study was designed to investigate the ameliorative effects of the co-administration of phycocyanin with GA3 induced oxidative stress and histopathological changes in the liver. Forty male albino rats were randomly divided into four groups. Group I (control group) received normal saline for 6 weeks, Group II (GA3 treated group) received 3.85 mg/kg body weight GA3 once daily for 6 weeks, Group III (phycocyanin treated group) received Phycocyanin 200 mg/kg body weight/day for 6 weeks orally dissolved in distilled water and Group IV was treated with GA3 and phycocyanin at the same doses as groups 2 and 3. All treatments were given daily using intra-gastric intubation and continued for 6 weeks. Our results revealed significant downregulation of antioxidant enzyme activities and their mRNA levels (CAT, GPx and Cu-Zn, SOD) with marked elevation of liver enzymes and extensive fibrous connective tissue deposition with large biliary cells in hepatic tissue of GA3 treated rats, while treatment with phycocyanin improved the antioxidant defense system, liver enzymes and structural hepatocytes recovery in phycocyanin treated group with GA3. These data confirm the antioxidant potential of Phycocyanin and provide strong evidence to support the co-administration of Phycocyanin during using GA3.

Fish oil supplementation decreases oxidative stress but does not affect platelet-activating factor bioactivity in lungs of asthmatic rats

Dietary fish oil supplementation increases the content of n-3 polyunsaturated fatty acids (PUFA) in cellular membranes. The highly unsaturated nature of n-3 PUFA could result in an enhanced lipid peroxidation in the oxidative environment characteristic of asthma. The oxidative reaction cascade culminates in an increased production of components associated to oxidative stress and of an important proinflammatory mediator platelet-activating factor (PAF)-like lipid. We evaluated the effect of fish oil supplementation in asthmatic rats upon the PAF bioactivity and parameters related to oxidative stress in the lung. Fish oil supplementation of asthmatic rats resulted in lower concentrations of nitrite (1.719 ± 0.137 vs. 2.454 ± 0.163 nmol/mL) and lipid hydroperoxide (72.190 ± 7.327 vs. 120.200 ± 11.270 nmol/mg protein). In asthmatic animals, fish oil increased the activities of superoxide dismutase (EC 1.15.1.1) (33.910 ± 2.325 vs. 24.110 ± 0.618 U/mg protein) and glutathione peroxidase (EC 1.11.1.9) (164.100 ± 31.250 vs. 12.590 ± 5.234 U/mg protein). However, fish oil did not affect PAF bioactivity in lung tissue of asthmatic rats (0.545 ± 0.098 340/380 vs. 0.669 ± 0.101 340/380 nm ratio). Considering the two-step process--oxidative stress and PAF bioactivity--fish oil exhibited a divergent action on these aspects of asthmatic inflammation, since the supplement lowered oxidative stress in the lungs of asthmatic rats, presenting an antioxidant effect, but did not affect PAF bioactivity. This suggests a dual effect of fish oil on oxidative stress and inflammation in asthma.

Protective Effect of Proanthocyanidin against Diabetic Oxidative Stress

We investigated the antidiabetic potential of proanthocyanidin and its oligomeric form in STZ-induced diabetic model rats and db/db type 2 diabetic mice. Proanthocyanidin ameliorated the diabetic condition by significant decreases of serum glucose, glycosylated protein, and serum urea nitrogen as well as decreases of urinary protein and renal-AGE in STZ-induced diabetic rats and decrease of serum glucose as well as significant decrease of glycosylated protein in db/db type 2 diabetic mice. The suppression of ROS generation and elevation of the GSH/GSSG ratio were also observed in the groups administered proanthocyanidin. Moreover, proanthocyanidin, especially its oligomeric form, affected the inflammatory process with the regulation of related protein expression, iNOS, COX-2 and upstream regulators, NF-κB, and the IκB-α. In addition, it had a marked effect on hyperlipidemia through lowering significant levels of triglycerides, total cholesterol, and NEFA. Moreover, expressions in the liver of SREBP-1 and SREBP-2 were downregulated by the administration of proanthocyanidins. The protective effect against hyperglycemia and hyperlipidemia in type 1 and 2 diabetic models was significantly strong in the groups administered the oligomeric rather than polymeric form. This suggests that oligomers act as a regulator in inflammatory reactions caused by oxidative stress in diabetes.

n-3 polyunsaturated fatty acids and autoimmune-mediated glomerulonephritis

Consumption of n-3 polyunsaturated fatty acids (PUFAs) found in fish oil suppresses inflammatory processes making these fatty acids attractive candidates for both the prevention and amelioration of several organ-specific and systemic autoimmune diseases. Both pre-clinical and clinical studies have been conducted to determine whether fish oils containing the n-3 PUFAs docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) can be used in the prevention and treatment of immunoglobulin A nephropathy (IgAN) and lupus nephritis. In a toxin-induced mouse model that mimics the early stages of IgAN, n-3 PUFA consumption suppresses aberrant interleukin (IL)-6-driven IgA production and mesangial IgA immune complex deposition by impairing phosphorylation of upstream kinases and activation of transcription factors essential for IL-6 gene transcription. n-3 PUFAs can also suppress production of anti-double-stranded DNA IgG antibodies and the resultant development of lupus nephritis in the NZBW F1 mouse and related models. These effects have been linked in part to impaired expression of proinflammatory cytokines and adhesion molecules as well as increases in antioxidant enzymes in kidney and immune organs. Several recent clinical trials have provided compelling evidence that n-3 PUFA supplementation could be useful in treatment of human IgAN and lupus nephritis, although some other studies suggest such supplementation might be without benefit. Future investigations employing genomics/proteomics and novel genetically altered mice should provide further insight into how n-3 PUFAs modulate these diseases as well help to identify clinically relevant biomarkers. The latter could be employed in future well-designed, long-term clinical studies that will resolve current controversies on n-3 PUFA efficacy in autoimmune-mediated glomerulonephritis.

Active principle of kimchi, 3-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid, retards fatty streak formation at aortic sinus of apolipoprotein E knockout mice

We examined the beneficial effects of an active principle in kimchi, 3-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid (HDMPPA), on atherogenesis in apolipoprotein E knockout (apoE KO) mice. ApoE KO mice were fed an atherogenic diet containing 1% cholesterol (control group) with an intraperitoneal injection of chemically synthesized HDMPPA (10 mg/kg/day) (HDMPPA group) for 8 weeks. The aortic sinus atherosclerotic lesion size in the HDMPPA group (n = 10) was significantly smaller (control vs. HDMPPA, 280,790 vs. 165,409 microm(2), P < .001). The level of reactive oxygen species (ROS) in the HDMPPA group was lower by 14%, compared with the control group (P < .05). Aortic NADPH oxidase activity was significantly lower in the HDMPPA group than in the control group. HDMPPA suppressed the mRNA expression of p47phox and rac-1 of NADPH oxidase by 27.2% and 46.0%, respectively, compared with values of the control group. In conclusion, HDMPPA in kimchi may attenuate atherosclerosis in apoE KO mice through retardation of ROS generation via down-regulating the mRNA expression of p47phox and rac-1, which are the components of NADPH oxidase.

Attenuation of diabetic complications by C-phycoerythrin in rats: antioxidant activity of C-phycoerythrin including copper-induced lipoprotein and serum oxidation

In the present study, the protective role of purified C-phycoerythrin (C-PE) against diabetic complications and Cu-mediated lipoprotein oxidation was evaluated. C-PE (25 and 50 mg/kg body weight per d) was administered to experimental streptozotocin-nicotinamide-induced type 2 diabetic male rats for 28 d. C-PE treatment successfully ameliorated diabetic complications by decreasing food intake, organ weights, serum concentrations of glucose, cholesterol, TAG, VLDL-cholesterol, creatinine, uric acid and thiobarbituric acid-reactive substances (TBARS), with increases in body weight, Hb, total protein, bilirubin and ferric-reducing ability of plasma values. Hepatic and renal tissues demonstrated significant decreases in TBARS, lipid hydroperoxide and conjugated diene contents, with increases in superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione, vitamin E and vitamin C levels. Furthermore, the 4-week ex vivo and in vitro administration of C-PE (0.5 and 1.0 mg/ml) indicated a decrease in Cu-mediated serum oxidation. The kinetics of the LDL oxidation profile showed significant prolongation of the lag phase with declines in oxidation rate, conjugated dienes, lipid hydroperoxide and TBARS. Results indicated the involvement of C-PE in the amelioration of diabetic complications by significant reductions in oxidative stress and oxidised LDL-triggered atherogenesis.

Molecular inflammation: underpinnings of aging and age-related diseases

Recent scientific studies have advanced the notion of chronic inflammation as a major risk factor underlying aging and age-related diseases. In this review, low-grade, unresolved, molecular inflammation is described as an underlying mechanism of aging and age-related diseases, which may serve as a bridge between normal aging and age-related pathological processes. Accumulated data strongly suggest that continuous (chronic) upregulation of pro-inflammatory mediators (e.g., TNF-alpha, IL-1beta, IL-6, COX-2, iNOS) are induced during the aging process due to an age-related redox imbalance that activates many pro-inflammatory signaling pathways, including the NF-kappaB signaling pathway. These pro-inflammatory molecular events are discussed in relation to their role as basic mechanisms underlying aging and age-related diseases. Further, the anti-inflammatory actions of aging-retarding caloric restriction and exercise are reviewed. Thus, the purpose of this review is to describe the molecular roles of age-related physiological functional declines and the accompanying chronic diseases associated with aging. This new view on the role of molecular inflammation as a mechanism of aging and age-related pathogenesis can provide insights into potential interventions that may affect the aging process and reduce age-related diseases, thereby promoting healthy longevity.

Antioxidative and anti-inflammatory actions of docosahexaenoic acid and eicosapentaenoic acid in renal epithelial cells and macrophages

Oxidative stress due to excessive reactive species (RS) and weakened antioxidant defenses is causally associated with inflammation and inflammatory mediators. To investigate the effects of the major fish oil ingredients, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), on oxidative stress-related inflammatory status, we conducted in vitro experiments utilizing rat renal epithelial cells (NRK-52E) and murine macrophages (RAW 264.7) by assessing their effects on the generation of cyclooxygenase (COX)-2-derived and xanthine oxidase (XOD)-derived RS, reduced glutathione (GSH) levels, and antioxidative enzyme activities. Additionally, 6-keto-prostaglandin (PG) F1alpha, PGE2, and nitrite levels were measured in lipopolysaccharide-stimulated RAW 264.7 macrophages. Results showed that the generation of RS from arachidonic acid through the COX-2 and XOD pathways was effectively suppressed by DHA and EPA, while GSH levels and antioxidative enzyme activities were significantly enhanced by DHA and EPA. Furthermore, levels of inflammatory mediators (thromboxane B2, PGE2, and 6-keto-PGF1alpha) and nitrite were effectively down-regulated by DHA and EPA. These results strongly indicate that DHA and EPA exert antioxidative and anti-inflammatory actions by reducing the cellular levels of RS, pro-inflammatory mediators, and nitrite levels and by maintaining higher GSH levels and antioxidative enzyme activities.

Ameliorative effects of proanthocyanidin on oxidative stress and inflammation in streptozotocin-induced diabetic rats

Recent evidence strongly suggests that oxidative stress due to redox imbalance is causally associated with inflammatory processes and various diseases including diabetes. We examined the effects of proanthocyanidin from persimmon peel, using both oligomers and polymers, against oxidative stress with elucidation of the underlying mechanisms in streptozotocin-induced diabetic rats. The elevation of lipid peroxidation in the kidney and serum under the diabetic condition was decreased by the administration of proanthocyanidin. The suppression of reactive oxygen species generation and elevation of the reduced glutathione/oxidized glutathione ratio were observed in the groups administered proanthocyanidin. These results support the protective role of proanthocyanidin from oxidative stress induced by diabetes. Moreover, proanthocyanidin, especially its oligomeric form, affected the inflammatory process with regulation of related protein expression, inducible nitric oxide synthase, cyclooxygenase-2, and upstream regulators, nuclear factor kappaB, and inhibitor-binding protein kappaB-alpha. Proanthocyanidin ameliorated the diabetic condition by decreases of serum glucose, glycosylated protein, serum urea nitrogen, urinary protein, and renal advanced glycation endproducts. In particular, oligomeric proanthocyanidin exerted a stronger protective activity than the polymeric form. This suggests that the polymerization of proanthocyanidin has an effect on its protective effect against diabetes. The present study supports the beneficial effect of proanthocyanidin against diabetes and oxidative stress-related inflammatory processes.

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.