ROLE OF DIETARY LIPID AND ANTIOXIDANTS IN BONE METABOLISM

Long Bone Mineral Loss, Bone Microstructural Changes and Oxidative Stress After Eimeria Challenge in Broilers

The objective of this study was to evaluate the impact of coccidiosis on bone quality and antioxidant status in the liver and bone marrow of broiler chickens. A total of 360 13-day old male broilers (Cobb 500) were randomly assigned to different groups (negative control, low, medium-low, medium-high, and highest dose groups) and orally gavaged with different concentrations of Eimeria oocysts solution. Broiler tibia and tibia bone marrow were collected at 6 days post-infection (6 dpi) for bone 3-D structural analyses and the gene expression related to osteogenesis, oxidative stress, and adipogenesis using micro-computed tomography (micro-CT) and real-time qPCR analysis, respectively. Metaphyseal bone mineral density and content were reduced in response to the increase of Eimeria challenge dose, and poor trabecular bone traits were observed in the high inoculation group. However, there were no significant structural changes in metaphyseal cortical bone. Medium-high Eimeria challenge dose significantly increased level of peroxisome proliferator-activated receptor gamma (PPARG, p < 0.05) and decreased levels of bone gamma-carboxyglutamate protein coding gene (BGLAP, p < 0.05) and fatty acid synthase coding gene (FASN, p < 0.05) in bone marrow. An increased mRNA level of superoxide dismutase type 1 (SOD1, p < 0.05) and heme oxygenase 1 (HMOX1, p < 0.05), and increased enzyme activity of superoxide dismutase (SOD, p < 0.05) were found in bone marrow of Eimeria challenged groups compared with that of non-infected control. Similarly, enzyme activity of SOD and the mRNA level of SOD1, HMOX1 and aflatoxin aldehyde reductase (AKE7A2) were increased in the liver of infected broilers (p < 0.05), whereas glutathione (GSH) content was lower in the medium-high challenge group (p < 0.05) compared with non-challenged control. Moreover, the mRNA expression of catalase (CAT) and nuclear factor kappa B1 (NFKB1) showed dose-depend response in the liver, where expression of CAT and NFKB1 was upregulated in the low challenge group but decreased with the higher Eimeria challenge dosage (p < 0.05). In conclusion, high challenge dose of Eimeria infection negatively affected the long bone development. The structural changes of tibia and decreased mineral content were mainly located at the trabecular bone of metaphyseal area. The change of redox and impaired antioxidant status following the Eimeria infection were observed in the liver and bone marrow of broilers.

Climate and demography drive 7000 years of dietary change in the Central Andes

Explaining the factors that influence past dietary variation is critically important for understanding changes in subsistence, health, and status in past societies; yet systematic studies comparing possible driving factors remain scarce. Here we compile the largest dataset of past diet derived from stable isotope δ¹³C‰ and δ¹⁵N‰ values in the Americas to quantitatively evaluate the impact of 7000 years of climatic and demographic change on dietary variation in the Central Andes. Specifically, we couple paleoclimatic data from a general circulation model with estimates of relative past population inferred from archaeologically derived radiocarbon dates to assess the influence of climate and population on spatiotemporal dietary variation using an ensemble machine learning model capable of accounting for interactions among predictors. Results reveal that climate and population strongly predict diet (80% of δ15N‰ and 66% of δ13C‰) and that Central Andean diets correlate much more strongly with local climatic conditions than regional population size, indicating that the past 7000 years of dietary change was influenced more by climatic than socio-demographic processes. Visually, the temporal pattern suggests decreasing dietary variation across elevation zones during the Late Horizon, raising the possibility that sociopolitical factors overrode the influence of local climatic conditions on diet during that time. The overall findings and approach establish a general framework for understanding the influence of local climate and demography on dietary change across human history.

Induction of Osteogenic MC3T3-E1 Cell Differentiation by Nacre and Flesh Lipids of Tunisian Pinctada radiata

The flesh of the Pinctada radiata pearl oyster from coastal Tunisia is considered as a high source of n-3 and n-6 and its shell nacre layer is a promising osteogenic biomaterial. Fatty acid (FA) analysis showed that the major components found in total FA (TFA) were 14:0, 16:0, and 18:0 saturated FA (SFA); 16:1, 18:1, and 20:1 monoenoic FA; 20:4n-6 (ARA), 22:5n-3 (DPA). Characteristically high levels of 20:5n-3 (EPA) and 22:6n-3 (DHA) (6.53-89.75 mg/100 g TFA) polyunsaturated FA (PUFA) were found, respectively, in the TFA of nacre and flesh. Evaluated the effects in vitro of lipids extracted from nacre (Ln) and from flesh (Lc) of P. radiata on growth and the differentiation of osteoblasts. Cytotoxicity tests (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide [MTT] and lactic acid dehydrogenase c [LDH]) demonstrated that both extracts are nontoxic. Alizarin Red staining was used in an osteoblast differentiation model using the osteoblast MC3T3-E1 cell line. It showed that the FA of both extracts induced osteoblast differentiation leading to mineralization. Reverse transcription-polymerase chain reaction (RT-PCR) showed a significantly higher expression of osteocalcin (Bglap) and runt-related transcription (Runx2) in MC3T3-E1 cells in the presence of Ln. No difference of osteopontin (Spp1) and Collagen type I (Col1a1) genes compared to the control was observed. In conclusion, these results supported, obtained from our in vitro experimental model used, the interest/potential of lipids extracted from nacre and P. radiata flesh to stimulate bone formation.

Pros and cons of fatty acids in bone biology

Despite the growing interest in deciphering the causes and consequences of obesity-related disorders, the mechanisms linking fat intake to bone behaviour remain unclear. Since bone fractures are widely associated with increased morbidity and mortality, most notably in elderly and obese people, bone health has become a major social and economic issue. Consistently, public health system guidelines have encouraged low-fat diets in order to reduce associated complications. However, from a bone point of view, mechanisms linking fat intake to bone alteration remain quite controversial. Thus, after more than a decade of dedicated studies, this timely review offers a comprehensive overview of the relationships between bone and fatty acids. Using clinical evidences as a starting-point to more complex molecular elucidation, this work highlights the complexity of the system and reveals that bone alteration that cannot be solved simply by taking ω-3 pills. Fatty acid effects on bone metabolism can be both direct and indirect and require integrated investigations. Furthermore, even at the level of a single cell, one fatty acid is able to trigger several different independent pathways (receptors, metabolites…) which may all have a say in the final cellular metabolic response.

Prevention of bone loss by phloridzin, an apple polyphenol, in ovariectomized rats under inflammation conditions

Aging and sex hormones related changes lead to inflammatory and oxidant conditions, which are involved in the pathogenesis of osteoporosis. Recent studies have suggested that polyphenols may exert a protective effect in such conditions. We assessed the effect of phloridzin (Phlo), a flavonoid exclusively found in apple, on bone metabolism in ovariectomized (OVX) or sham-operated (SH) rats with and without inflammation. Six-month-old Wistar rats were allocated to two equal groups that received either a control diet or a diet supplemented with 0.25% Phlo for 80 days. Three weeks before necropsy, inflammation was induced by subcutaneous injection of talc in 10 animals of each group. At necropsy, ovariectomy decreased both total (T-BMD) and metaphyseal (M-BMD) femoral bone mineral density (P < 0.01). Inflammation conditions, checked by an increase in the spleen weight and alpha1-acid glycoprotein concentration in OVX rats, exacerbated the decrease in T-BMD (g/cm2) (as well as M-BMD) observed in castrated animals (P < 0.05). Daily Phlo intake prevented ovariectomy-induced bone loss in conditions of inflammation as shown by T-BMD and M-BMD (P < 0.05). At the diaphyseal site, BMD was improved by Phlo in OVX rats with or without inflammation (P < 0.05). These results could be explained by changes in bone remodeling as the increased urinary deoxypyridinoline excretion in OVX and OVXinf animals was prevented by the polyphenol-rich diet (P < 0.001), while plasma osteocalcin concentration was similar in all experimental groups. In conclusion, Phlo consumption may provide protection against ovariectomy-induced osteopenia under inflammation conditions by improving inflammation markers and bone resorption.

Preventive effect of Abelmoschus manihot (L.) Medik. on bone loss in the ovariectomised rats

Because the biggest culprit in pathogenesis of osteoporosis is oestrogen deficiency, hormone replacement therapy remained the mainstay for prevention. However most of postmenopausal women are more inclined to use natural alternative. We thus investigated the ability of Abelmoschus manihot, a herbal medicine to prevent bone loss in ovariectomised rats. Female Wistar rats were sham operated (SH: 8) or ovariectomised (OVX: 24). On day 0, OVX rats were randomly assigned to groups as follows: eight received 10% Abelmoschus manihot leaves in their diet, eight were given 15% Abelmoschus manihot leaves and eight were untreated (OVX). Compounds were mixed with a soy protein-free diet and given orally for 3 months. At necropsy, bone mineral density (BMD) in the femur and in its metaphyseal zone was lower in OVX than SH (p<0.05). This osteopenia was prevented by consumption of the highest dose of Abelmoschus manihot leaves. Bone mineral content (BMC) in the total femur and its metaphyseal and diaphyseal subregions was improved, as well (p<0.05). This could be explained by a trend towards decreased bone resorption. The lowest dose did not elicit any significant effect. In conclusion, Abelmoschus manihot consumption, at the dose of 15% in the diet, provided bone-sparing effects by improving both BMD and BMC.

Long-term supplementation of various dietary lipids alters bone mineral content, mechanical properties and histological characteristics of Japanese quail

The purpose of this study was to investigate the effects of long-term supplementation of fat in the diets on the fatty acid composition, chemical, mechanical, and histological properties of tibial bone. Month-old male Japanese quail were fed a basal diet containing either soybean oil (SBO), hydrogenated soybean oil (HSBO), chicken fat (CF), or menhaden fish oil (FO) at 50 g/kg of the diet and maintained on these diets for 7 mo. Lipid treatments did not affect body weight, food intake, tibial length, or diameter. The FO diet group had the highest percentage of tibial ash, and both the FO and HSBO significantly increased tibial mineral content compared to those given SBO or CF. The type and amount of fatty acids in the diets had a profound influence on fatty acid composition of lipids in tibial cortical bones. Quail fed FO had the highest concentration of (n-3) fatty acids, and those fed SBO were highest in (n-6) fatty acids. The HSBO diet, containing high level of trans-fatty acids, led to the accumulation of these fatty acids in bone. In quail, long-term supplementation of FO or HSBO increased tibial shear force and shear stress and improved histological cortical thickness and density when compared to those given SBO or CF. These results suggest that long-term exposure to a FO or HSBO diet have a significant beneficial effect on bone metabolism.

First-line treatment for osteoarthritis. Part 2: Nonpharmacologic interventions and evaluation

Because of the chronic nature of osteoarthritis, nonpharmacologic interventions provide the client with self-care strategies that may lessen pain, improve physical functioning, and increase independence and sense of control. Nonpharmacologic interventions include exercise, rest and joint protection, heat and cold, hydrotherapy, therapeutic touch, acupuncture/acupressure, biofeedback, hypnotherapy, cognitive-behavioral techniques, activity and home maintenance modification, nutrition, and transportation interventions. Most of these therapies are very useful for nurses as independent interventions. Suggestions for evaluation of interventions are made.

Omega-3 polyunsaturated fatty acids and skeletal health

This minireview on skeletal biology describes the actions of prostaglandins and cytokines involved in the local regulation of bone metabolism, it documents the role of lipids in bone biology, and it presents relationships between fatty acids and other factors that impact skeletal metabolism. The data presented herein show consistent and reproducible beneficial effects of omega-3 (n-3) fatty acids on bone metabolism and bone/joint diseases. Polyunsaturated fatty acids modulate eicosanoid biosynthesis in numerous tissues and cell types, alter signal transduction, and influence gene expression. These effects have not been explored in the skeletal system. Future research on n-3 fatty acids in bone biology should focus on the following two aspects. First, the further elucidation of how n-3 fatty acids alter biochemical and molecular processes involved in bone modeling and bone cell differentiation, and second, the evaluation of the potential pharmaceutical applications of these nutraceutical fatty acids in maintaining bone mineral status and controlling inflammatory bone/joint diseases.

Mineral, amino acid, and hormonal composition of chicken eggshell powder and the evaluation of its use in human nutrition

Chicken eggshell powder (ESP) might be an attractive source of Ca for human nutrition. To study its nutritional value, we analyzed minerals, amino acids, and hormones in commercially available Slovakian ESP. The mineral composition was compared with three Dutch ESP samples that differed in feed and housing, a Japanese ESP, refined CaCO3, and an oyster shell supplement. Chicken eggshell powder contains high levels of Ca (mean +/- SD/g EPS: 401+/-7.2 mg) and Sr (372+/-161 microg) when compared with recommended or estimated daily intakes for humans 51 to 70 yr of age. Levels of potentially toxic Pb, Al, Cd, and Hg were very low as were levels of V, B, Fe, Zn, P, Mg, N, F, Se, Cu, and Cr. Large differences in the levels of F, Se, Cu, Cr, and Sr in the Dutch and Slovakian ESP indicated a strong influence of feed and environment. The small protein fraction of ESP contains high levels of Gly and Arg. Furthermore, small amounts of transforming growth factor-beta1 (0.75 to 7.28 ng/g ESP), calcitonin (10 to 25 ng/g ESP), and progesterone (0.30 to 0.33 ng/g ESP) were detected. Estradiol-17beta and calcitriol were below the detection limit of the methods used. Compared with ESP, refined CaCO3 was found to contain increased levels of Cd, and the oyster shell supplement showed increased levels of Al and Cd. Therefore, ESP seems to have a beneficial composition with about 39% of elemental Ca, relevant amounts of Sr, and low levels of Al, Pb, Cd and Hg. It may be used as a Ca source in human nutrition.

Conjugated linoleic acid and bone biology

Osteoporosis, osteoarthritis and inflammatory joint disease afflict millions of people worldwide. Inflammatory cytokines inhibit chondrocyte proliferation and induce cartilage degradation for which part of the response is mediated by PGE2. Excess production of PGE2 is linked to osteoporosis and arthritis and is associated with bone and proteoglycan loss. PGE2 also influences the IGF-I/IGFBP axis to facilitate bone and cartilage formation. Recent investigations with growing rats given butter fat and supplements of CLA demonstrated an increased rate of bone formation and reduced ex vivo bone PGE2 production, respectively. Furthermore, the supplements of CLA isomers resulted in their enrichment in lipids of various bone compartments of animals. The effects of CLA on bone biology in rats (IGF action and cytokines) appear to be dependent on the level of n-6 and n-3 fatty acids in the diet; however, these studies generally showed that CLA decreased ex vivo bone PGE2 production and in osteoblast-like cultures. Anti-inflammatory diets, including nutraceutical applications of CLA, may be beneficial in moderating cyclooygenase 2 (COX-2) activity or expression (influencing PGE2 biosynthesis) and might help to reduce rheumatoid arthritis (secondary osteoporosis). This review summarizes findings of CLA on bone modeling in rats and effects on cellular functions of osteoblasts and chondrocytes. These experiments indicate that CLA isomers possess anti-inflammatory activity in bone by moderating prostanoid formation.

Factors regulating bone maturity and strength in poultry

Adolescent meat-type poultry and cage layers exhibit a high incidence of bone problems that include bone weakness, deformity, breakage, and infection and osteoporosis-related mortalities. These problems include economic and welfare issues. To improve bone quality in poultry, it is essential to understand the physiological basis of bone maturity and strength in poultry. A complex array of factors that include structural, architectural, compositional, physiological, and nutritional factors interactively determine bone quality and strength. Bone is approximately 70% mineral, 20% organic, and 10% water. Collagen is the major organic matrix that confers tensile strength to the bone, whereas hydroxyapatite provides compressional strength. In recent years, the roles of different collagen crosslinks have been shown to be important in the increase of bone mechanical strength. Similarly, age-related glyco-oxidative modifications of collagen have been shown to increase the stiffness of collagen. These posttranslational modifications of matrix can affect bone quality as it would be affected by the changes in the mineralization process. Our studies show that the growth in the tibia continued until 25 wk of age, which correlated with the increase in the content of hydroxylysylpridinoline (HP) and lysylpyridinoline (LP), the collagen crosslinks. The tibia from 5-wk-old chicks were strong but brittle because of low collagen crosslinks and high mineral content. Bone maturity may relate to its crosslink content. Compared to crosslink content, bone density and ash content showed moderate increases during growth. The bones from younger turkeys were more susceptible to corticosteroid-induced stunting of growth, which also resulted in decreased bone strength. This review discusses how different factors can compromise bone strength by reducing growth, altering shape, affecting mineralization, and affecting collagen crosslinking.