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

Unraveling the Omega-3 Puzzle: Navigating Challenges and Innovations for Bone Health and Healthy Aging

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs, n-3 PUFAs), including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA), are essential polyunsaturated fats primarily obtained from fatty fish and plant-based sources. Compelling evidence from preclinical and epidemiological studies consistently suggests beneficial effects of ω-3 PUFAs on bone health and healthy aging processes. However, clinical trials have yielded mixed results, with some failing to replicate these benefits seen in preclinical models. This contraindication is mainly due to challenges such as low bioavailability, potential adverse effects with higher doses, and susceptibility to oxidation of ω-3 fatty acids, hindering their clinical effectiveness. This review comprehensively discusses recent findings from a clinical perspective, along with preclinical and epidemiological studies, emphasizing the role of ω-3 PUFAs in promoting bone health and supporting healthy aging. Additionally, it explores strategies to improve ω-3 PUFA efficacy, including nanoparticle encapsulation and incorporation of specialized pro-resolving mediators (SPM) derived from DHA and EPA, to mitigate oxidation and enhance solubility, thereby improving therapeutic potential. By consolidating evidence from various studies, this review underscores current insights and future directions in leveraging ω-3 PUFAs for therapeutic applications.

Revolutionizing Cardiovascular Health with Nano Encapsulated Omega-3 Fatty Acids: A Nano-Solution Approach

Omega-3 polyunsaturated fatty acids (ω-3 PUFAs) offer diverse health benefits, such as supporting cardiovascular health, improving cognitive function, promoting joint and musculoskeletal health, and contributing to healthy aging. Despite their advantages, challenges like oxidation susceptibility, low bioavailability, and potential adverse effects at high doses persist. Nanoparticle encapsulation emerges as a promising avenue to address these limitations while preserving stability, enhanced bioavailability, and controlled release. This comprehensive review explores the therapeutic roles of omega-3 fatty acids, critically appraising their shortcomings and delving into modern encapsulation strategies. Furthermore, it explores the potential advantages of metal-organic framework nanoparticles (MOF NPs) compared to other commonly utilized nanoparticles in improving the therapeutic effectiveness of omega-3 fatty acids within drug delivery systems (DDSs). Additionally, it outlines future research directions to fully exploit the therapeutic benefits of these encapsulated omega-3 formulations for cardiovascular disease treatment.

Impact of health and lifestyle food supplements on periodontal tissues and health

According to the new classification, periodontitis is defined as a chronic multifactorial inflammatory disease associated with dysbiotic biofilms and characterized by progressive destruction of the tooth-supporting apparatus. This definition, based on the current scientific evidence, clearly indicates and emphasizes, beside the microbial component dental biofilm, the importance of the inflammatory reaction in the progressive destruction of periodontal tissues. The idea to modulate this inflammatory reaction in order to decrease or even cease the progressive destruction was, therefore, a logical consequence. Attempts to achieve this goal involve various kinds of anti-inflammatory drugs or medications. However, there is also an increasing effort in using food supplements or so-called natural food ingredients to modulate patients' immune responses and maybe even improve the healing of periodontal tissues. The aim of this chapter of Periodontology 2000 is to review the evidence of various food supplements and ingredients regarding their possible effects on periodontal inflammation and wound healing. This review may help researchers and clinicians to evaluate the current evidence and to stimulate further research in this area.

Antarctic krill (Euphausia superba) oil modulatory effects on ethanol-induced acute injury of the gastric mucosa in rats

Antarctic krill oil (KO) prepared using supercritical carbon dioxide extraction and characterized using gas chromatography-mass spectrometry was used to investigate its preventive effect on ethanol-induced gastric tissue damage in a rat model in vivo. KO characterization showed that 74.96% of the unsaturated fatty acids consist of oleic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Rats pre-treated with KO (100, 200, and 500 mg/kg) showed mitigated oxidative stress through enhanced antioxidant enzyme superoxide dismutase (SOD) and reducing enzymes malondialdehyde (MDA) and myeloperoxidase (MPO) in gastric mucosal injury induced by ethanol. Additionally, the secretion of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β), the expression of the IκBα/NF-κB signaling pathway, and nitric oxide (NO) production was suppressed. The results also demonstrated a significant decrease in histological injury and hemorrhage scores in a dose-dependent manner in the KO range. Therefore, KO has potential as a food supplement to alleviate ethanol-induced acute gastric mucosal injury.

Omega-3 fatty acid-rich fish oil supplementation prevents rosiglitazone-induced osteopenia in aging C57BL/6 mice and in vitro studies

Rosiglitazone is an effective insulin-sensitizer, however associated with bone loss mainly due to increased bone resorption and bone marrow adiposity. We investigated the effect of the co-administration of fish oil rich in omega-3 fatty acids (FAs) on rosiglitazone-induced bone loss in C57BL/6 mice and the mechanisms underlying potential preventive effect. Mice fed the iso-caloric diet supplemented with fish oil exhibited significantly higher levels of bone density in different regions compared to the other groups. In the same cohort of mice, reduced activity of COX-2, enhanced activity of alkaline phosphatase, lower levels of cathepsin k, PPAR-γ, and pro-inflammatory cytokines, and a higher level of anti-inflammatory cytokines were observed. Moreover, fish oil restored rosiglitazone-induced down-regulation of osteoblast differentiation and up-regulation of adipocyte differentiation in C3H10T1/2 cells and inhibited the up-regulation of osteoclast differentiation of RANKL-treated RAW264.7 cells. We finally tested our hypothesis on human Mesenchymal Stromal Cells differentiated to osteocytes and adipocytes confirming the beneficial effect of docosahexaenoic acid (DHA) omega-3 FA during treatment with rosiglitazone, through the down-regulation of adipogenic genes, such as adipsin and FABP4 along the PPARγ/FABP4 axis, and reducing the capability of osteocytes to switch toward adipogenesis. Fish oil may prevent rosiglitazone-induced bone loss by inhibiting inflammation, osteoclastogenesis, and adipogenesis and by enhancing osteogenesis in the bone microenvironment.

Fat-1 transgenic mice rich in endogenous omega-3 fatty acids are protected from lipopolysaccharide-induced cardiac dysfunction

Aims

Cardiac malfunctions developing in result of sepsis are hard to treat so they eventually contribute to the increased mortality. Previous reports indicated for therapeutic potential of exogenous ω‐3 polyunsaturated fatty acids (PUFA) in sepsis, but potential benefits of this compound on the malfunctional heart have not been explored yet. In the present study, we investigated whether the constantly elevated levels of endogenous ω‐3 PUFA in transgenic fat‐1 mice would alleviate the lipopolysaccharide (LPS)‐induced cardiac failure and death.

Methods and results

After both wild type (WT) and transgenic fat‐1 mice were challenged with LPS, a Kaplan–Meier curve and echocardiography were performed to evaluate the survival rates and cardiac function. Proteomics analysis, RT‐PCR, western blotting, immune‐histochemistry, and transmission electron microscopy were further performed to investigate the underlying mechanisms. Results showed that transgenic fat‐1 mice exhibited the significantly lower mortality after LPS challenge as compared with their WT counterparts (30% vs. 42.5%, P < 0.05). LPS injection consistently impaired the left ventricular contractile function and caused the cardiac injury in the wild type mice, but not significantly affected the fat‐1 mice (P < 0.05). Proteomic analyses, ELISA, and immunohistochemistry further revealed that myocardium of the LPS‐challenged fat‐1 mice demonstrated the significantly lower levels of pro‐inflammatory markers and ROS than WT mice. Meaningfully, the LPS‐treated fat‐1 mice also demonstrated a significantly higher levels of LC3 II/I and Atg7 expressions than the LPS‐treated WT mice (P < 0.05), as well as displayed a selectively increased levels of peroxisome proliferator‐activated receptor (PPAR) γ and sirtuin (Sirt)‐1 expression, associated with a parallel decrease in NFκB activation.

Conclusions

The fat‐1 mice were protected from the detrimental LPS‐induced inflammation and oxidative stress, and exhibited enhancement of the autophagic flux activities, associating with the increased Sirt‐1 and PPARγ signals.

Bioactive Lipids in Age-Related Disorders

Our own studies and those of others have shown that defects in essential fatty acid (EFA) metabolism occurs in age-related disorders such as obesity, type 2 diabetes mellitus, hypertension, atherosclerosis, coronary heart disease, immune dysfunction and cancer. It has been noted that in all these disorders there could occur a defect in the activities of desaturases, cyclo-oxygenase (COX), and lipoxygenase (LOX) enzymes leading to a decrease in the formation of their long-chain products gamma-linolenic acid (GLA), arachidonic acid, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA). This leads to an increase in the production of pro-inflammatory prostaglandin E2 (PGE2), thromboxanes (TXs), and leukotrienes (LTs) and a decrease in anti-inflammatory lipoxin A4, resolvins, protectins and maresins. All these bioactive molecules are termed as bioactive lipids (BALs). This imbalance in the metabolites of EFAs leads to low-grade systemic inflammation and at times acute inflammatory events at specific local sites that trigger the development of various age-related disorders such as obesity, type 2 diabetes mellitus, hypertension, coronary heart disease, atherosclerosis, and immune dysfunction as seen in rheumatoid arthritis, lupus, nephritis and other localized inflammatory conditions. This evidence implies that methods designed to restore BALs to normal can prevent age-related disorders and enhance longevity and health.

Bone Benefits of Fish Oil Supplementation Depend on its EPA and DHA Content

The preventive effect of high-dose (9%) regular-fish oil (FO) against bone loss during aging has been demonstrated, but the effects of a low-dose (1%–4%) of a highly purified concentrated FO (CFO) has not been elucidated. The aim of this study was to determine the dose-dependent effect of a CFO against bone loss in C57BL/6 female mice during aging. Twelve-month old mice were fed with 1% and 4% CFO and 4% safflower oil (SFO) diets, including a group with a 4% regular-FO diet and a group with a lab chow diet for 12 months. Bone mineral density (BMD) was analyzed by dual-energy x-ray absorptiometry (DXA) before and after the dietary intervention. At the end of dietary intervention, bone resorption markers in serum and inflammatory markers in bone marrow and splenocytes and inflammatory signaling pathways in the bone marrow were analyzed. As compared to the 4% SFO control, 4% CFO maintained higher BMD during aging, while 1% CFO offered only a mild benefit. However, the 1% CFO fed group exhibited slightly better BMD than the 4% regular-FO fed group. BMD loss protection by CFO was accompanied by reduced levels of the bone resorption marker, TRAP, and the osteoclast-stimulating-factor, RANKL, without affecting the decoy-receptor of RANKL, osteoprotegerin (OPG). Further, CFO supplementation was associated with an increase in the production of IL-10, IL-12, and IFN-γ and a decrease in the production of TNF-α and IL-6, and the activation of NF-κB, p38 MAPK, and JNK signaling pathways. In conclusion, the supplementation of 4% CFO is very efficient in maintaining BMD during aging, whereas 1% CFO is only mildly beneficial. CFO supplementation starting at middle age may maintain better bone health during aging.

Polyunsaturated fatty acids: any role in rheumatoid arthritis?

Background

Polyunsaturated fatty acids (PUFAs) are members of the family of fatty acids and are included in the diet. Particularly, western diet is usually low in n-3 PUFAs and high in n-6 PUFAs. PUFAs play a central role in the homeostasis of immune system: n-6 PUFAs have predominantly pro-inflammatory features, while n-3 PUFAs seem to exert anti-inflammatory and pro-resolving properties. Rheumatoid arthritis (RA) is a chronic inflammatory arthritis in which many inflammatory pathways contribute to joint and systemic inflammation, disease activity, and structural damage. Research on PUFAs could represent an important opportunity to better understand the pathogenesis and to improve the management of RA patients.

Methods

We searched PubMed, Embase, EBSCO-Medline, Cochrane Central Register of Controlled Trials (CENTRAL), CNKI and Wanfang to identify primary research reporting the role of n-3 PUFAs in rheumatoid arthritis both in humans and in animal models up to the end of March 2017.

Results

Data from animal models allows to hypothesize that n-3 PUFAs supplementation may represent an interesting perspective in future research as much in prevention as in treating RA. In humans, several case-control and prospective cohort studies suggest that a high content of n-3 PUFAs in the diet could have a protective role for incident RA in subjects at risk. Moreover, n-3 PUFAs supplementation has been assessed as a valuable therapeutic option also for patients with RA, particularly in order to improve the pain symptoms, the tender joint count, the duration of morning stiffness and the frequency of NSAIDs assumption.

Conclusions

n-3 PUFAs supplementation could represent a promising therapeutic option to better control many features of RA. The impact of n-3 PUFAs on radiographic progression and synovial histopathology has not been yet evaluated, as well as their role in early arthritis and the combination with biologics.

A Clinical Study Evaluating the Effects of Fluvastatin on Serum Osteoprotegerin Levels in Rheumatoid Arthritis Patients

Osteoprotegerin (OPG), a member of the tumor necrosis factor receptor family, has been identified as a critical regulator of bone resorption. Considering the possible role of OPG in rheumatoid arthritis (RA) and in the osteoclastogenesis suppression effects of statins, the present study aims to investigate the effects of fluvastatin on serum levels OPG and disease activity score (DAS) in patients with RA. Forty patients with RA were randomized in a placebo-controlled trial to receive 40 mg fluvastatin or placebo as an adjunct to existing disease-modifying antirheumatic drug (DMARD) therapy (methotrexate, leflunomide, hydroxychloroquine). Patients were followed up over 12 weeks. OPG and disease activity variables were measured at baseline and after 12 weeks of treatment. After 12 weeks, the OPG level was significantly increased in the fluvastatin group compared to the placebo group. DAS-28 was significantly decreased in the fluvastatin group compared to the placebo group. C-reactive protein (CRP), morning stiffness, swollen joint count (SJC), and tender joint count (TJC) were significantly decreased in the fluvastatin group compared to the placebo group; however, erythrocyte sedimentation rate (ESR), modified health assessment questionnaire (MHAQ), and visual analogue screen (VAS) were not changed significantly. In conclusion, fluvastatin administration could increase the OPG levels and improve disease activity variables in patients with RA. Therefore, fluvastatin may serve a potential benefit in the treatment of RA patients.

Effects of linseed oil and palm oil on growth performance, tibia fatty acid and biomarkers of bone metabolism in broilers

1. This study was conducted to determine the effects of different dietary fat sources on growth performance, tibia fatty acids and biomarkers of bone metabolism in broilers. 2. One-d-old commercial Arbor Acres broilers were fed with a maize-soya bean basal diet for 42 d, supplemented with oils according to the following 5 treatments: lard (lard group); linseed oil (linseed oil group); palm oil (palm oil group); linseed oil + palm oil (60:40 or 40:60 w/w, LP-1 group and LP-2 group, respectively). 3. No significant differences in weight gain, feed intake and gain/feed ratio were observed between the lard and linseed oil groups. Birds fed on palm oil had significantly greater weight gain and feed intake than those fed on lard or linseed oil. Growth performance in LP-1 and LP-2 was significantly greater than that of single-oil groups. 4. Tibia growth and bone characteristics were not influenced by supplementation with lard, linseed oil, or palm oil alone, but broilers fed on a mixture of fats had significantly greater tibia weight and length compared to broilers fed on linseed oil. Bone mineral density in tibia was significantly increased in LP-1 and LP-2 groups. 5. Supplementation of linseed oil alone or in combination with palm oil enhanced apparent digestibility of calcium, reduced serum calcium and increased tibia calcium concentrations. Moreover, supplementation with linseed oil alone or in combination with palm oil had a positive effect on biomarkers of bone growth. 6. The combination of linseed and palm oils was beneficial for growth performance, tibia growth and biomarkers of bone metabolism.

Conjugated linoleic Acid prevents ovariectomy-induced bone loss in mice by modulating both osteoclastogenesis and osteoblastogenesis

Postmenopausal osteoporosis due to estrogen deficiency is associated with severe morbidity and mortality. Beneficial effects of conjugated linoleic acid (CLA) on bone mineral density (BMD) have been reported in mice, rats and humans, but the effect of long term CLA supplementation against ovariectomy-induced bone loss in mice and the mechanisms underlying this effect have not been studied yet. Eight-week old ovariectomized (Ovx) and sham operated C57BL/6 mice were fed either a diet containing 0.5 % safflower oil (SFO) or 0.5 % CLA for 24 weeks to examine BMD, bone turn over markers and osteotropic factors. Bone marrow (BM) cells were cultured to determine the effect on inflammation, osteoclastogenesis, and osteoblastogenesis. SFO/Ovx mice had significantly lower femoral, tibial and lumbar BMD compared to SFO/Sham mice; whereas, no difference was found between CLA/Ovx and CLA/Sham mice. CLA inhibited bone resorption markers whereas enhanced bone formation markers in Ovx mice as compared to SFO-fed mice. Reverse transcriptase polymerase chain reaction and fluorescence activated cell sorting analyses of splenocytes revealed that CLA inhibited pro-osteoclastogenic receptor activator of NF-κB (RANKL) and stimulated decoy receptor of RANKL, osteoprotegerin expression. CLA also inhibited pro-inflammatory cytokine and enhanced anti-inflammatory cytokine production of lipopolysaccharide-stimulated splenocytes and BM cells. Furthermore, CLA inhibited osteoclast differentiation in BM and stimulated osteoblast differentiation in BM stromal cells as confirmed by tartrate resistant acid phosphatase and Alizarin Red staining, respectively. In conclusion, CLA may prevent postmenopausal bone loss not only by inhibiting excessive bone resorption due to estrogen deficiency but also by stimulating new bone formation. CLA might be a potential alternative therapy against osteoporotic bone loss.

Concentrated fish oil (Lovaza(R)) extends lifespan and attenuates kidney disease in lupus-prone short-lived (NZBxNZW)F1 mice

A growing number of reports indicate that anti-inflammatory actions of fish oil (FO) are beneficial against systemic lupus erythematosus (SLE). However, the majority of pre-clinical studies were performed using 5-20% FO, which is higher than the clinically relevant dose for lupus patients. The present study was performed in order to determine the effective low dose of FDA-approved concentrated FO (Lovaza®) compared to the commonly used FO-18/12 (18-Eicosapentaenoic acid [EPA]/12-Docosahexaenoic acid [DHA]). We examined the dose-dependent response of Lovaza® (1% and 4%) on an SLE mouse strain (NZBxNZW)F1 and compared the same with 1% and 4% placebo, as well as 4% FO-18/12, maintaining standard chow as the control. Results show for the first time that 1% Lovaza® extends maximal lifespan (517 d) and 4% Lovaza® significantly extends both the median (502 d) and maximal (600 d) life span of (NZBxNZW)F1 mice. In contrast, FO-18/12 extends only median lifespan (410 d) compared to standard chow diet (301 d). Additionally, 4% Lovaza® significantly decreased anti-dsDNA antibodies, reduced glomerulonephritis and attenuated lipopolysaccharide-induced pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) in splenocytes compared to placebo. 4% Lovaza® was also shown to reduce the expression of inflammatory cytokines, including IL-1β, IL-6 and TNF-α, while increasing renal anti-oxidant enzymes in comparison to placebo. Notably, NFκB activation and p65 nuclear translocation were lowered by 4% Lovaza® compared to placebo. These data indicate that 1% Lovaza® is beneficial, but 4% Lovaza® is more effective in suppressing glomerulonephritis and extending life span of SLE-prone short-lived mice, possibly via reducing inflammation signaling and modulating oxidative stress.

DHA is a more potent inhibitor of breast cancer metastasis to bone and related osteolysis than EPA

Breast cancer patients often develop bone metastasis evidenced by osteolytic lesions, leading to severe pain and bone fracture. Attenuation of breast cancer metastasis to bone and associated osteolysis by fish oil, rich in EPA and DHA, has been demonstrated previously. However, it was not known whether EPA and DHA differentially or similarly affect breast cancer bone metastasis and associated osteolysis. In vitro culture of parental and luciferase gene encoded MDA-MB-231 human breast cancer cell lines treated with EPA and DHA revealed that DHA inhibits proliferation and invasion of breast cancer cells more potently than EPA. Intra-cardiac injection of parental and luciferase gene encoded MDA-MB-231 cells to athymic NCr nu/nu mice demonstrated that DHA-treated mice had significantly less breast cancer cell burden in bone, and also significantly less osteolytic lesions than EPA-treated mice. In vivo cell migration assay as measured by luciferase intensity revealed that DHA attenuated cell migration specifically to the bone. Moreover, the DHA-treated group showed reduced levels of CD44 and TRAP positive area in bone compared to EPA-treated group. Breast cancer cell burden and osteolytic lesions were also examined in intra-tibially breast cancer cell injected mice and found less breast cancer cell growth and associated osteolysis in DHA-treated mice as compared to EPA-treated mice. Finally, doxorubicin-resistant MCF-7 (MCF-7dox) human breast cancer cell line was used to examine if DHA can improve sensitization of MCF-7dox cells to doxorubicin. DHA improved the inhibitory effect of doxorubicin on proliferation and invasion of MCF-7dox cells. Interestingly, drug resistance gene P-gp was also down-regulated in DHA plus doxorubicin-treated cells. In conclusion, DHA attenuates breast cancer bone metastasis and associated osteolysis more potently than EPA, possibly by inhibiting migration of breast cancer cell to the bone as well as by inhibiting osteoclastic bone resorption.

Supplementation with fish oil and genistein, individually or in combination, protects bone against the adverse effects of methotrexate chemotherapy in rats

Cancer chemotherapy has been shown to induce long-term skeletal side effects such as osteoporosis and fractures; however, there are no preventative treatments. This study investigated the damaging effects of anti-metabolite methotrexate (MTX) subcutaneous injections (0.75 mg/kg BW) for five days and the potential protective benefits of daily oral gavage of fish oil at 0.5 mL/100 g BW (containing 375 mg of n-3 PUFA/100 g BW), genistein (2 mg/100 g BW), or their combination in young adult rats. MTX treatment alone significantly reduced primary spongiosa height and secondary spongiosa trabecular bone volume. Bone marrow stromal cells from the treated rats showed a significant reduction in osteogenic differentiation but an increase in adipogenesis ex vivo. Consistently, stromal cells had significantly higher mRNA levels of adipogenesis-related proliferator activator activated receptor-γ (PPAR-γ) and fatty acid binding protein (FABP4). MTX significantly increased the numbers of bone-resorbing osteoclasts and marrow osteoclast precursor cell pool while significantly enhancing the mRNA expression of receptor activator for nuclear factor kappa B ligand (RANKL), the RANKL/osteoprotegerin (OPG) ratio, interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in the bone. Supplementary treatment with fish oil and/or genistein significantly preserved trabecular bone volume and osteogenesis but suppressed MTX-induced adipogenesis and increases in osteoclast numbers and pro-osteoclastogenic cytokine expression. Thus, Fish oil and/or genistein supplementation during MTX treatment enabled not only preservation of osteogenic differentiation, osteoblast number and bone volume, but also prevention of MTX treatment-induced increases in bone marrow adiposity, osteoclastogenic cytokine expression and osteoclast formation, and thus bone loss.

Association of n-3 polyunsaturated fatty acid intake with bone mineral density in postmenopausal women

n-3 Polyunsaturated fatty acids (n-3 fatty acids) have been shown to have a beneficial effect on bone in animal studies, although little is known about their role in bone metabolism in humans. We investigated the association between bone mineral density (BMD) and daily n-3 fatty acid intake. This cross-sectional, community-based, epidemiologic study was conducted among 205 healthy postmenopausal women (mean age 63.5 years, range 46-79). We examined BMD, serum N-terminal propeptide of type I collagen (PINP), urinary type-I collagen cross-linked-N-telopeptide (uNTX), total cholesterol, triglycerides, and high-density lipoprotein cholesterol. Nutrient intake was calculated using a food-frequency questionnaire. BMD was measured at the lumbar spine and femoral neck by dual-energy X-ray absorptiometry. Simple regression analysis showed that intake of neither n-3 fatty acid nor n-6 fatty acid was associated with age or lipid metabolism indices. However, simple regression analysis showed that n-3 fatty acid intake was positively associated with both lumbar spine BMD and femoral neck BMD. n-6 fatty acid intake was positively associated with femoral neck BMD but not lumbar spine BMD. Multiple regression analysis showed that n-3 fatty acid intake was positively associated with lumbar spine BMD after adjustment for age, BMI, duration of menopausal state, grip strength, PINP, uNTX, and intakes of calcium, vitamin D, vitamin K, and n-6 fatty acid. In conclusion, n-3 fatty acid intake was positively associated with lumbar spine BMD independent of bone resorption and serum levels of cholesterol and triglycerides in postmenopausal women.

The omega-6 arachidonic fatty acid, but not the omega-3 fatty acids, inhibits osteoblastogenesis and induces adipogenesis of human mesenchymal stem cells: potential implication in osteoporosis

Arachidonic fatty acid (AA) induces adipogenesis in human mesenchymal stem cells cultures, and high concentrations inhibit osteoblastogenesis; whereas eicosapentaenoic and docosahexaenoic fatty acids do not induce adipogenesis and do not inhibit osteoblastogenesis. In mesenchymal stem cells, omega-6 arachidonic polyunsaturated fatty acid promotes the differentiation of adipocytes and inhibits the osteoblast differentiation. While omega-3 fatty acids do not affect the adipogenic differentiation their effects on osteoblastogenesis are less relevant. An increased ratio of omega-3/omega-6 fatty acid consumption can prevent bone mass loss.

INTRODUCTION

Consumption of omega-3 may protect against osteoporosis since they may inhibit osteoclastogenesis. However, with aging, MSC in bone marrow are increasingly differentiated into adipocytes, reducing the number of osteoblasts. Products derived from omega-6 and omega-3 metabolism may affect MSC differentiation into osteoblasts and adipocytes.

METHODS

Human MSC have been differentiated into osteoblasts or adipocytes in the presence of omega-6 (AA), or omega-3 (DHA and EPA), and osteoblastic and adipocytic markers have been analyzed.

RESULTS

AA decreases the expression of osteogenic markers and the osteoprotegerin/receptor activator of nuclear factor kappa β ligand gene expression ratio (opg/rankl). High concentrations of AA inhibit the mineralization and cause the appearance of adipocytes in MSC differentiating into osteoblasts to a higher extent than DHA or EPA. In MSC differentiated into adipocytes, AA increases adipogenesis, while DHA and EPA do not affect it. AA caused the appearance of adipocytes in undifferentiated MSC. The lipoxygenase gene (alox15b) is induced by omega-3 in MSC induced to osteoblasts, and by omega-6 in MSC induced to adipocytes.

CONCLUSIONS

An increase in the intake of omega-3 respect to omega-6 may provide protection against the loss of bone mass, since omega-6 favors the osteoclastic activity by diminishing the opg/rankl gene expression in osteoblasts and promotes MSC differentiation into adipocytes, thus diminishing the production of osteoblasts.

Fish oil concentrate delays sensitivity to thermal nociception in mice

Fish oil has been used to alleviate pain associated with inflammatory conditions such as rheumatoid arthritis. The anti-inflammatory property of fish oil is attributed to the n-3 fatty acids docosahexaenoic acid and eicosapentaenoic acid. Contrarily, vegetable oils such as safflower oil are rich in n-6 fatty acids which are considered to be mediators of inflammation. This study investigates the effect of n-3 and n-6 fatty acids rich oils as dietary supplements on the thermally induced pain sensitivity in healthy mice. C57Bl/6J mice were fed diet containing regular fish oil, concentrated fish oil formulation (CFO) and safflower oil (SO) for 6 months. Pain sensitivity was measured by Plantar test and was correlated to the expression of acid sensing ion channels (ASICs), transient receptor potential vanilloid 1 (TRPV1) and c-fos in dorsal root ganglion cells. Significant delay in sensitivity to thermal nociception was observed in mice fed CFO compared to mice fed SO (p<0.05). A significant diminution in expression of ion channels such as ASIC1a (64%), ASIC13 (37%) and TRPV1 (56%) coupled with reduced expression of c-fos, a marker of neuronal activation, was observed in the dorsal root ganglion cells of mice fed CFO compared to that fed SO. In conclusion, we describe here the potential of fish oil supplement in reducing sensitivity to thermal nociception in normal mice.

The fat-1 transgene in mice increases antioxidant potential, reduces pro-inflammatory cytokine levels, and enhances PPAR-gamma and SIRT-1 expression on a calorie restricted diet

Both n-3 fatty acids (FA) and calorie-restriction (CR) are known to exert anti-inflammatory and anti-oxidative effects in animals and humans. In this study, we investigated the synergistic anti-inflammatory and anti-oxidative capacity of n-3 FA and CR using Fat-1 transgenic mice (Fat-1) that are capable of converting n-6 FA to n-3 FA endogenously. Wild type (WT) and Fat-1 mice were maintained on ad libitum (AL) or CR (40% less than AL) AIN-93 diet supplemented with 10% corn oil (rich in n-6 FA) for 5 months. Significantly lower levels of n-6/n-3 FA ratio were observed in serum, muscle and liver of Fat-1 mice fed AL or CR as compared to that of WT mice fed AL or CR. Muscle catalase (CAT), super oxide dismutase (SOD), glutathione peroxidase (GPX) activities, and liver CAT and SOD activities were found higher in Fat-1 mice as compared to that of WT mice. These activities were more pronounced in Fat-1/CR group as compared to other groups. Serum pro-inflammatory markers, such as tumor necrosis factor (TNF)α, interleukin (IL)-1β and IL-6 were found lower in Fat-1 mice, as compared to that of WT mice. This anti-inflammatory effect was also more pronounced in Fat-1/CR group as compared to that of other groups. Furthermore, significantly higher levels of peroxisome proliferator-activated receptor (PPA R)gamma and life prolonging gene, sirtuin (SIRT)-1 expression were found in liver of Fat-1/CR mice, as compared to that of WT/CR mice. These data suggest that n-3 FA along with moderate CR may prolong lifespan by attenuating inflammation and oxidative stress.

Endogenously produced n-3 fatty acids protect against ovariectomy induced bone loss in fat-1 transgenic mice

Aging is associated with bone loss, leading to increased risk of fractures. Recently, there is growing interest in identifying nutritional supplements that can prevent bone loss with minimum side effects. There is increasing evidence for the beneficial effects of n-3 fatty acids in the prevention of bone loss. A transgenic mouse model (fat-1) that produces n-3 fatty acids endogenously and its wild type counterpart were used in this study to determine the effects of endogenously produced n-3 fatty acids on serum bone turnover markers, long bones, and lumbar vertebrae. Serum alkaline phosphatase and P1NP levels decreased significantly in wild type mice after ovariectomy. No significant changes were seen in osteocalcin. Cancellous and cortical bone mass were higher in the femur of fat-1 mice. In wild type mice, there was significant loss of bone after ovariectomy in the distal femur, femoral neck, proximal tibia, and fourth lumbar vertebra. However, in fat-1 mice, there was no, or significantly less, bone lost after ovariectomy in all the sites studied. We conclude that endogenously produced n-3 fatty acids can attenuate ovariectomy induced bone loss in the different bone sites studied, mainly as a consequence of decreased bone resorption at the endosteal surface.

Effects of long-term supplementation with omega-3 fatty acids on longitudinal changes in bone mass and microstructure in mice

A diet rich in omega-3s has previously been suggested to prevent bone loss. However, evidence for this has been limited by short exposure to omega-3 fatty acids (FAs). We investigated whether a diet enriched in eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) for the entire adult life of mice could improve bone microstructure and strength. Thirty female mice received a diet enriched in DHA or EPA or an isocaloric control diet from 3 to 17 months of age. Changes in bone microstructure were analyzed longitudinally and biomechanical properties were analysed by a three-point bending test. Bone remodelling was evaluated by markers of bone turnover and histomorphometry. Trabecular bone volume in caudal vertebrae was improved by EPA or DHA at 8 months (+26.6% and +17.2%, respectively, compared to +3.8% in controls, P=.01), but not thereafter. Trabecular bone loss in the tibia was not prevented by omega-3 FAs (BV/TV -94%, -93% and -97% in EPA, DHA and controls, respectively). EPA improved femur cortical bone volume (+8.1%, P<.05) and thickness (+4.4%, P<.05) compared to controls. EPA, but not DHA, reduced age-related decline of osteocalcin (-70% vs. -83% in controls, P<.05). EPA and DHA increased leptin levels (7.3±0.7 and 8.5±0.5 ng ml⁻¹, respectively, compared to 4.5±0.9 ng ml⁻¹ in controls, P=.001); however, only EPA further increased IGF-1 levels (739±108 ng ml⁻¹, compared to 417±58 ng ml⁻¹ in controls, P=.04). These data suggest that long-term intake of omega-3 FA, particularly EPA, may modestly improve the structural and mechanical properties of cortical bone by an increase in leptin and IGF-1 levels, without affecting trabecular bone loss.

Endogenous n-3 fatty acids protect ovariectomy induced bone loss by attenuating osteoclastogenesis

Beneficial effects of n-3 fatty acids (FA) on bone mineral density (BMD) have been reported in mice, rats and human beings, but the precise mechanisms involved have not been described. This study used the Fat-1 mouse, a transgenic model that synthesizes n-3 FA from n-6 FA to directly determine if outcome of bone health were correlated with n-3 FA. Ovariectomized (Ovx) and sham operated wild-type (WT) and Fat-1 mice were fed an AIN-93M diet containing 10% corn oil for 24 weeks. BMD was analysed by dual energy x-ray absorptiometry. Fat-1 Ovx mice exhibited significantly lower level of osteotropic factors like receptor activator of NF-kappaB ligand and tartrate-resistant acid phosphatase (TRAP)5b in serum and higher BMD in distal femoral metaphysis, proximal tibial metaphysis, femoral diaphysis and lumbar vertebra as compared to WT Ovx mice. LPS-stimulated bone marrow (BM) cells from Fat-1 Ovx mice produced significantly lower level of pro-inflammatory cytokines like tumour necrosis factor-alpha, interleukin (IL)-1-beta, IL-6 and higher level of anti-inflammatory cytokines like IL-10, IFN-gamma and higher level of nitric oxide as compared to BM cells from WT Ovx mice. LPS-stimulated COX-II activity as well as NF-kappaB activation in BM cells from Fat-1 Ovx mice was significantly less as compared to BM cells from WT Ovx mice. Furthermore, Fat-1 BM cells generated significantly less number of TRAP osteoclast-like cells as compared to WT BM cells. In conclusion, we offer further insight into the mechanisms involved in preventing the BMD loss in Ovx mice by n-3 FA using a Fat-1 transgenic mouse model.

Endogenous n-3 fatty acids protect ovariectomy induced bone loss by attenuating osteoclastogenesis

Beneficial effects of n-3 fatty acids (FA) on bone mineral density (BMD) have been reported in mice, rats and human beings, but the precise mechanisms involved have not been described. This study used the Fat-1 mouse, a transgenic model that synthesizes n-3 FA from n-6 FA to directly determine if outcome of bone health were correlated with n-3 FA. Ovariectomized (Ovx) and sham operated wild-type (WT) and Fat-1 mice were fed an AIN-93M diet containing 10% corn oil for 24 weeks. BMD was analysed by dual energy x-ray absorptiometry. Fat-1 Ovx mice exhibited significantly lower level of osteotropic factors like receptor activator of NF-kappaB ligand and tartrate-resistant acid phosphatase (TRAP)5b in serum and higher BMD in distal femoral metaphysis, proximal tibial metaphysis, femoral diaphysis and lumbar vertebra as compared to WT Ovx mice. LPS-stimulated bone marrow (BM) cells from Fat-1 Ovx mice produced significantly lower level of pro-inflammatory cytokines like tumour necrosis factor-alpha, interleukin (IL)-1-beta, IL-6 and higher level of anti-inflammatory cytokines like IL-10, IFN-gamma and higher level of nitric oxide as compared to BM cells from WT Ovx mice. LPS-stimulated COX-II activity as well as NF-kappaB activation in BM cells from Fat-1 Ovx mice was significantly less as compared to BM cells from WT Ovx mice. Furthermore, Fat-1 BM cells generated significantly less number of TRAP osteoclast-like cells as compared to WT BM cells. In conclusion, we offer further insight into the mechanisms involved in preventing the BMD loss in Ovx mice by n-3 FA using a Fat-1 transgenic mouse model.

Supplementation of diet with krill oil protects against experimental rheumatoid arthritis

BACKGROUND

Although the efficacy of standard fish oil has been the subject of research in arthritis, the effect of krill oil in this disease has yet to be investigated. The objective of the present study was to evaluate a standardised preparation of krill oil and fish oil in an animal model for arthritis.

METHODS

Collagen-induced arthritis susceptible DBA/1 mice were provided ad libitum access to a control diet or diets supplemented with either krill oil or fish oil throughout the study. There were 14 mice in each of the 3 treatment groups. The level of EPA + DHA was 0.44 g/100 g in the krill oil diet and 0.47 g/100 g in the fish oil diet. Severity of arthritis was determined using a clinical scoring system. Arthritis joints were analysed by histopathology and graded. Serum samples were obtained at the end of the study and the levels of IL-1alpha, IL-1beta, IL-7, IL-10, IL-12p70, IL-13, IL-15, IL-17 and TGF-beta were determined by a Luminex assay system.

RESULTS

Consumption of krill oil and supplemented diet significantly reduced the arthritis scores and hind paw swelling when compared to a control diet not supplemented with EPA and DHA. However, the arthritis score during the late phase of the study was only significantly reduced after krill oil administration. Furthermore, mice fed the krill oil diet demonstrated lower infiltration of inflammatory cells into the joint and synovial layer hyperplasia, when compared to control. Inclusion of fish oil and krill oil in the diets led to a significant reduction in hyperplasia and total histology score. Krill oil did not modulate the levels of serum cytokines whereas consumption of fish oil increased the levels of IL-1alpha and IL-13.

CONCLUSIONS

The study suggests that krill oil may be a useful intervention strategy against the clinical and histopathological signs of inflammatory arthritis.

N-3 polyunsaturated fatty acid effect in periodontal disease: state of art and possible mechanisms involved

Anti-inflammatory properties have been widely reported for n-3 polyunsaturated fatty acids (PUFAs) and some studies have been focalized on their possible role in the modulation of gingivitis and alveolar bone resorption in periodontal disease (PD). Increased formation of arachidonic acid-derived inflammatory eicosanoids and augmented oxidative stress are two molecular mechanisms pathogenetically involved in the progression of PD and known to be inhibited by n-3 PUFAs in PD setting. The present review will focus also on other molecular pathways and factors known to be altered in the development of PD and known to be subject to n-3 PUFA modulation in other pathological settings different from PD. Overall, the available findings strongly encourage further experimental studies on animals subject to experimental PD and treated with n-3 PUFAs, long term n-3 PUFA intervention studies on PD patients and molecular studies to identify additional potential molecular routes of n-3 PUFA action in PD.

Altered bone metabolism in inflammatory disease: role for nutrition

Osteoporosis is a major public health problem, and as life expectancy and the world's population continue to increase will become even more important. Thus, there is an urgent need to develop and implement nutritional approaches and policies for the prevention and treatment of osteoporosis. Patients with some chronic inflammatory diseases appear to be more likely to develop osteopenia, and in some cases earlier in life, which is of particular concern as the incidence of inflammatory diseases in the Western world is increasing. While the cause of bone loss in patients with inflammatory disease is multifactorial, nutrition may have a role. Many of these patients may have one or more nutritional deficiencies, which can lead to altered rates of bone metabolism. On the other hand, some nutritional factors may attenuate the inflammatory process itself, and thus may indirectly benefit bone metabolism and bone health in patients with inflammatory disease. The present review will consider these issues, particularly in the context of inflammatory bowel disease, coeliac diease and atherosclerosis.

Varying ratios of omega-6: omega-3 fatty acids on the pre-and postmortem bone mineral density, bone ash, and bone breaking strength of laying chickens

The purpose of this study was to investigate the effects of varying ratios of n-6 to n-3 fatty acids in the diets of White Leghorn chickens on tibia bone characteristics [bone mineral density, bone mineral content (BMC), ash bone mineral content, bone morphology, and cortical thickness] and tibia bone strength parameters (ultimate force, bending stress, maximum strain, Young's modulus of elasticity, area under the curve, and moment of inertia). Seventy-five 16-wk-old female White Leghorn chickens were randomly assigned to 1 of 5 dietary ratios of n-6 to n-3 fatty acids: 47.8:1, 18.0:1, 7.6:1, 5.9:1, or 4.7:1. Corn oil was the n-6 fatty acid source, whereas flax oil provided the n-3 fatty acids. Bone density was measured on the left tibia via dual-energy x-ray absorptiometry (DXA) prior to killing and after excision. Bones were ashed in a muffle furnace at 500 degrees F. Tibia bones were broken by using a 3-point bending rig. Results showed no significant effect of diet on bone characteristics. There were no significant differences among diet groups for parameters of bone strength except cortical thickness (P < or = 0.01). Bone mineral content determined by ashing was significantly different by 9.2% (P < or = 0.0001) from BMC determined in vivo by DXA; however, there were no differences in ex vivo BMC and BMC ash, although they were highly correlated (r = 0.99, P < or = 0.0001). We concluded that there was no effect of n-3 fatty acids on tibia bone in mature White Leghorn chickens. The GE Lunar Prodigy DXA instrument significantly underestimated the in vivo BMC in chickens.

New endogenous anti-inflammatory and proresolving lipid mediators: implications for rheumatic diseases

Prostaglandins and leukotrienes are lipid mediators that carry out pivotal roles in host defense and acute inflammation. Failure to completely resolve an acute inflammatory response can lead to chronic inflammation, scarring, and eventual loss of tissue function. Until recently, it was thought that tissue resolution of acute inflammation was a passive event. However, it is now known than lipoxins, which--like prostaglandins and leukotrienes--are also derived from arachidonic acid, are active anti-inflammatory and proresolution mediators, acting in part by reducing neutrophil entry to the inflammation site and stimulating the uptake of apoptotic polymorphonuclear leukocytes by macrophages. Novel families of locally acting and locally generated mediators derived from omega-3 polyunsaturated fatty acids have also been identified as biosynthetically active components in the resolution phase of inflammation. The new families of chemical mediators are termed 'resolvins' and 'protectins' because individual members of each family are stereospecific in controlling the duration and magnitude of inflammation in animal models. Possible deficiencies in the biosynthesis of lipoxins, resolvins, and protectins, and/or their signal transduction, might underlie some aspects of pathogenesis in chronic inflammatory diseases.

Phase 2 enzyme induction by conjugated linoleic acid improves lupus-associated oxidative stress

Conjugated linoleic acid (CLA) exhibits anticancer and anti-inflammatory properties. Its ability to increase total GSH (GSH+GSSG) amount and gamma-glutamylcysteine ligase (gammaGCL) protein expression was recently associated with the inhibition of typical pathological signs in MRL/MpJ-Fas(lpr) mice (MRL/lpr). In the present study the ability of CLA to modulate oxidative stress and phase 2 enzyme activity in the same animal model was investigated. Disease severity was associated with age-dependent production of anti-double-stranded DNA antibodies (anti-dsDNA IgGs) and with enhanced extent of oxidative stress markers: reduced total GSH, increased protein 3-nitrotyrosines (3-NT), and protein-bound carbonyl (PC) amounts. To examine the effect of CLA on antioxidant status, CLA or olive oil (as control) was administered to pregnant MRL/lpr mice. Significantly higher total GSH and Trolox equivalent antioxidant capacity (TEAC) levels were measured in serum of CLA-treated dams (and their pups), as compared with controls. Finally, the antioxidant and chemopreventive properties of CLA were investigated in old MRL/lpr mice. Sera of CLA-treated mice contained higher concentrations of total GSH which were negatively correlated with the levels of oxidative stress markers. Moreover, increased GSH, gammaGCL, glutathione S-transferase (GSTs), and NAD(P)H:quinone oxidoreductase (NQO1) activities were measured in liver and spleen of CLA-treated animals. In conclusion our data indicate that the activation of detoxifying enzymes may be one of the mechanisms whereby dietary CLA down-regulates oxidative stress in MRL/lpr mice.

Omega-3 fatty acid effect on alveolar bone loss in rats

Gingival inflammation and alveolar bone resorption are hallmarks of adult periodontitis, elicited in response to oral micro-organisms such as Porphyromonas gingivalis. We hypothesized that omega (omega)-3 fatty acids (FA) dietary supplementation would modulate inflammatory reactions leading to periodontal disease in infected rats. Rats were fed fish oil (omega-3 FA) or corn oil (n-6 FA) diets for 22 weeks and were infected with P. gingivalis. Rats on the omega-3 FA diet exhibited elevated serum levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), documenting diet-induced changes. PCR analyses demonstrated that rats were orally colonized by P. gingivalis; increased IgG antibody levels substantiated this infection. P. gingivalis-infected rats treated with omega-3 FA had significantly less alveolar bone resorption. These results demonstrated the effectiveness of an omega-3 FA-supplemented diet in modulating alveolar bone resorption following P. gingivalis infection, and supported that omega-3 FA may be a useful adjunct in the treatment of periodontal disease.

Conjugated linoleic acid and chromium lower body weight and visceral fat mass in high-fat-diet-fed mice

More than half of the U.S. population has a body mass index of 25 kg/m2 or more, which classifies them as overweight or obese. Obesity is often associated with comorbidities such as diabetes, cardiovascular diseases, and cancer. CLA and chromium have emerged as major dietary supplements that reduce body weight and fat mass, and increase basal metabolic rate in animal models. However, studies show that CLA induces insulin resistance in mice and in humans, whereas Cr improves insulin sensitivity. Hence, we designed the present study to examine the combined effect of CLA and Cr on body composition and insulin sensitivity in a Balb/c mice (n = 10/group) model of high-fat-diet-induced obesity. CLA alone lowered body weight, total body fat mass, and visceral fat mass, the last of which decreased further with the combination of CLA and Cr. This effect was accompanied by decreased serum leptin levels in CLA-fed and CLA + Cr-fed mice, and by higher energy expenditure (EE) and oxygen consumption (OC) in CLA + Cr-fed mice. Serum levels of glucose, insulin, the pro-inflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6), as well as insulin resistance index (IRI), decreased with CLA, whereas CLA and Cr in combination had significant effects on insulin and IL-6 concentrations and IRI. In summary, CLA + Cr decreased body weight and fat mass in high-fat-diet-fed mice, which may be associated with decreased leptin levels and higher EE and OC.

Inhibition of inflammatory response in transgenic fat-1 mice on a calorie-restricted diet

Both n-3 fatty acids (n-3 FA) and calorie-restriction (CR) exert anti-inflammatory effects in animal models of autoimmunity and inflammation. In the present study we investigated the synergistic anti-inflammatory effects of n-3 FA and CR on LPS-mediated inflammatory responses using fat-1 transgenic mice that generate n-3 FA endogenously. Wild-type (WT) and fat-1 mice were maintained on ad libitum (AL) or CR (40% less than AL) diet for 5 mo; splenocytes were cultured in vitro with/without LPS. Our results show: (i) no difference in body weights between WT and fat-1 mice on AL or CR diets, (ii) lower n-6/n-3 FA ratio in splenocytes from fat-1 mice on both AL and CR diets, (iii) significant reduction in NF-kappaB (p65/p50) and AP-1 (c-Fos/c-Jun) DNA-binding activities in splenocytes from fat-1/CR mice following LPS treatment, and (iv) significant reduction in kappaB- and AP-1-responsive IL-6 and TNF-alpha secretion following LPS treatment in splenocytes from fat-1/CR mice. The inhibition of LPS-mediated effects was more pronounced in fat-1/CR mice when compared to fat-1/AL or WT/CR mice. These data show that transgenic expression of fat-1 results in decreased pro-inflammatory n-6 FA, and demonstrate for the first time that splenocytes from fat-1 mice on CR diet exhibit reduced pro-inflammatory response when challenged with LPS. These results suggest that n-3 lipids with moderate CR may confer protection in autoimmune and inflammatory diseases.

Conjugated linoleic acid protects against age-associated bone loss in C57BL/6 female mice

Osteoporosis is one of the major causes of morbidity in the elderly. Inflammation exerts a significant influence on bone turnover, inducing the chronic form of osteoporosis. Dietary nutrition has the capacity to modulate inflammatory response. Therefore, nutritional strategies and lifestyle changes may prevent age-related osteoporosis, thereby improving the quality of life of the elderly population. Conjugated linoleic acid (CLA) has been shown to positively influence calcium and bone metabolism. Hence, this study was undertaken to examine the effect of CLA on bone mineral density (BMD) in middle-aged C57BL/6 female mice. After 10 weeks on diet, CLA-fed mice (14 months) maintained a higher BMD in different bone regions than corn oil (CO)-fed mice. The increased BMD was accompanied by a decreased activity of proinflammatory cytokines (such as tumor necrosis factor alpha, interleukin-6 and the receptor activator of NF-kappaB ligand) and decreased osteoclast function. Furthermore, a significant decrease in fat mass and an increase in muscle mass were also observed in CLA-fed mice compared to CO-fed mice. In conclusion, these findings suggest that CLA may prevent the loss of bone and muscle mass by modulating markers of inflammation and osteoclastogenic factors.

Effect of fish oil on bone mineral density in aging C57BL/6 female mice

Life expectancy has increased considerably over the last century in the United States. It is expected that this longevity will be accompanied by an increase in the prevalence of osteoporosis and accompanying complications in the elderly population. Age-related loss of bone mass and bone fragility are major risk factors for osteoporosis, leading to an increased risk of fractures. Therefore, nutritional strategies and lifestyle changes that prevent age-related osteoporosis and improve the quality of life for the elderly population are urgently needed. Hence, the present study compared the effects of corn oil (CO; n-6 fatty acids; commonly present in Western diets) and fish oil (FO; n-3 fatty acids) on bone mineral density (BMD) in aging C57BL/6 female mice. After 6 months of dietary treatment, we found that 18-month-old FO-fed mice maintained higher BMD in different bone regions compared to CO-fed mice. These findings were accompanied by a decreased activity of pro-inflammatory cytokines, tumor necrosis factor-alpha and interleukin-6 in stimulated splenocytes; a nonsignificant but greater increase in bone formation markers alkaline phosphatase and osteocalcin in the serum; and lower osteoclast generation in bone marrow cell cultures in FO-fed mice. In conclusion, these findings suggest that providing n-3 fatty acids may have a beneficial effect on bone mass during aging by modulating bone formation and bone resorption factors.

Conjugated linoleic acid inhibits osteoclast differentiation of RAW264.7 cells by modulating RANKL signaling

Bone destruction is a pathological hallmark of several chronic inflammatory diseases, including rheumatoid arthritis, periodontitis, and osteoporosis. Inflammation-induced bone loss of this sort results from increased numbers of bone-resorbing osteoclasts. Numerous studies have indicated that conjugated linoleic acid (CLA) positively influences calcium and bone metabolism. Gene-deletion studies have shown that receptor activator of nuclear factor-kappaB ligand (RANKL) is one of the critical mediators of osteoclastogenesis. In this report, we examine the ability of CLA to suppress RANKL signaling and osteoclastogenesis in RAW264.7 cells, a murine monocytic cell line. Treatment of these cells with RANKL activated nuclear factor-kappaB (NF-kappaB), and preexposure of the cells to CLA significantly suppressed RANKL-induced NF-kappaB activation, including phosphorylation of I-kappaBalpha, degradation of I-kappaBalpha, and nuclear translocation of p65. RANKL induced osteoclastogenesis in these monocytic cells, and CLA inhibited RANKL-induced tumor necrosis factor-alpha production and osteoclast differentiation, including osteoclast-specific genes such as tartrate-resistant acid phosphatase, cathepsin K, calcitonin receptor, and matrix metalloproteinase-9 expression and osteoclast-specific transcription factors such as c-Fos, nuclear factor of activated T-cells expression, and bone resorption pit formation. CLA also inhibited RANKL-induced activation of mitogen-activated protein kinase p38 but had little effect on c-Jun N-terminal kinase activation. Collectively, these data demonstrate for the first time that CLA inhibits osteoclastogenesis by modulating RANKL signaling. Thus, CLA may have important therapeutic implications for the treatment of bone diseases associated with enhanced bone resorption by excessive osteoclastogenesis.

Different ratios of eicosapentaenoic and docosahexaenoic omega-3 fatty acids in commercial fish oils differentially alter pro-inflammatory cytokines in peritoneal macrophages from C57BL/6 female mice

The use of fish oil (FO) as a dietary supplement to prevent or reduce the severity of cardiovascular diseases and autoimmune disorders such as rheumatoid arthritis is receiving much attention. Several recent reports indicate that eating fish often or the use of small doses of FO capsules appears to have benefits against cardiovascular diseases. We have reported in the past that diets enriched with FO protect against renal diseases and prolong the life span of autoimmune-prone mice compared to corn oil (CO) diets. However, the optimum ratio of eicosapentaenoic acid (EPA) to docosahexaenoic acid (DHA) in commercially available FOs to reduce the production of various pro-inflammatory cytokines has not been well established. We, therefore, obtained deodorized FO from three sources containing different EPA/DHA contents, fed them to C57BL/6 mice for 8 weeks in a 10% (vol/wt) diet (oil A, 11/10; oil B, 14/9; oil C, 23/14) and compared them with (10%) CO-fed mice as control. TNF-alpha, IL-6 and IL-1beta were measured by enzyme-linked immunosorbent assay in thioglycollate-induced macrophages, 8 and 24 h after lipopolysaccharide treatment. The results showed a significant decrease in TNF-alpha after only 8 h in oil C. After 24 h, TNF-alpha, IL-6 and IL-1beta levels decreased only in mice fed oil C, although nonsignificant decreases were seen in mice fed oil A compared to mice fed CO. The antioxidant enzymes, catalase and glutathione transferase, were higher in kidneys of mice fed oil C compared to mice fed CO. The study suggests that anti-inflammatory activity may vary among different sources of FO due to variations in EPA/DHA content.

Effects of conjugated linoleic acid and exercise on bone mass in young male Balb/C mice

There is an increase in obesity among the population of industrialized countries, and dietary supplementation with Conjugated Linoleic Acid (CLA) has been reported to lower body fat mass. However, weight loss is generally associated with negative effects on bone mass, but CLA is reported to have beneficial effects on bone. Furthermore, another factor that is well established to have a beneficial effect on bone is exercise (EX). However, a combination therapy of CLA and EX on bone health has not been studied. In this paper, we report the beneficial effects of CLA and EX on bone, in four different groups of Balb-C young, male mice. There were 4 groups in our study: 1. Safflower oil (SFO) sedentary (SED); 2. SFO EX; 3. CLA SED; 4. CLA EX. Two months old mice, under their respective treatment regimens were followed for 14 weeks. Mice were scanned in vivo using a DEXA scanner before and after treatment. At the end of the treatment period, the animals were sacrificed, the left tibia was removed and scanned using peripheral quantitative computerized tomography (pQCT). The results showed that although CLA decreased gain in body weight by 35%, it however increased bone mass by both reducing bone resorption and increasing bone formation. EX also decreased gain in body weight by 21% and increased bone mass; but a combination of CLA and EX, however, did not show any further increase in bone mass. In conclusion, CLA increases bone mass in both cancellous and cortical bones, and the effects of CLA on bone is not further improved by EX in pure cortical bone of young male mice.

Effect of fish oil on offensive and defensive factors in gastric ulceration in rats

The effect of fish oil (FO) derived from Scomberoides commersonianus containing omega-3 polyunsaturated fatty acids was studied on gastric ulcers and as well as on offensive and defensive factors in gastric mucosal damage, following experimental gastric ulceration. FO significantly reduced the severity of ulceration in gastric ulcers induced by aspirin, cold-restraint stress (CRS), alcohol, and pylorus ligation. The results also indicated the potentiality of FO in maintaining the integrity of gastric mucosa by virtue of its effect on both offensive and defensive gastric mucosal factors. It decreased the offensive acid-pepsin secretion and augmented the defensive factors like mucin secretion, cellular mucus and life span of mucosal cells following pylorus ligation. FO significantly increased activity of anti-oxidant enzymes (catalase and glutathione peroxidase) and decreased lipid peroxidation in gastric mucosa of CRS rats. The study indicates the beneficial role of FO in gastric ulceration by inhibition of offensive mucosal factors and oxidative stress, and augmentation of defensive mucosal factors.