Oral Administration of .BETA.-Cryptoxanthin Induces Anabolic Effects on Bone Components in the Femoral Tissues of Rats in Vivo

Nutraceuticals and Functional Foods: A Comprehensive Review of Their Role in Bone Health

Bone health is the result of a tightly regulated balance between bone modeling and bone remodeling, and alterations of these processes have been observed in several diseases both in adult and pediatric populations. The imbalance in bone remodeling can ultimately lead to osteoporosis, which is most often associated with aging, but contributing factors can already act during the developmental age, when over a third of bone mass is accumulated. The maintenance of an adequate bone mass is influenced by genetic and environmental factors, such as physical activity and diet, and particularly by an adequate intake of calcium and vitamin D. In addition, it has been claimed that the integration of specific nutraceuticals such as resveratrol, anthocyanins, isoflavones, lycopene, curcumin, lutein, and β-carotene and the intake of bioactive compounds from the diet such as honey, tea, dried plums, blueberry, and olive oil can be efficient strategies for bone loss prevention. Nutraceuticals and functional foods are largely used to provide medical or health benefits, but there is an urge to determine which products have adequate clinical evidence and a strong safety profile. The aim of this review is to explore the scientific and clinical evidence of the positive role of nutraceuticals and functional food in bone health, focusing both on molecular mechanisms and on real-world studies.

The role of carotenoids in bone health-A narrative review

Osteoporosis constitutes a serious challenge for public health. Dietary patterns belong to important, modifiable risk factors of this disease. Therefore, what and in what quantities we consume on a daily basis are extremely relevant. It is commonly known that bone health is positively affected by vitamins (e.g., vitamin D and vitamin K) as well as mineral components (e.g., calcium and magnesium). However, the human diet consists of many other groups of compounds that exhibit a potential antiosteoporotic and supporting bone-building effect. These dietary components include carotenoids. This paper presents a broad review of studies on the influence of particular carotenoids (β-carotene, lutein, zeaxanthin, β-cryptoxanthin, and lycopene) on bones. The paper discusses up-to-date in vitro experiments and research on animal models and presents how the results translate into clinical effect in humans.

Bioactive Ingredients from Dairy-Based Lactic Acid Bacterial Fermentations for Functional Food Production and Their Health Effects

Lactic acid bacteria are traditionally applied in a variety of fermented food products, and they have the ability to produce a wide range of bioactive ingredients during fermentation, including vitamins, bacteriocins, bioactive peptides, and bioactive compounds. The bioactivity and health benefits associated with these ingredients have garnered interest in applications in the functional dairy market and have relevance both as components produced in situ and as functional additives. This review provides a brief description of the regulations regarding the functional food market in the European Union, as well as an overview of some of the functional dairy products currently available in the Irish and European markets. A better understanding of the production of these ingredients excreted by lactic acid bacteria can further drive the development and innovation of the continuously growing functional food market.

Anti-arthritic actions of β-cryptoxanthin against the degradation of articular cartilage in vivo and in vitro

An inverse correlation between the morbidity of rheumatoid arthritis and daily intake of β-cryptoxanthin has been epidemiologically shown. In this study, we investigated the effects of β-cryptoxanthin on the metabolism of cartilage extracellular matrix in vivo and in vitro. Oral administration of β-cryptoxanthin (0.1-1 mg/kg) to antigen-induced arthritic rats suppressed the loss of glycosaminoglycans in articular cartilage, which is accompanied by the interference of aggrecanase-mediated degradation of aggrecan. Inhibition of the interleukin 1α (IL-1α)-induced aggrecan degradation by β-cryptoxanthin was also observed with porcine articular cartilage explants in culture. β-Cryptoxanthin (1-10 μM) dose-dependently down-regulated the IL-1α-induced gene expression of aggrecanase 1 (ADAMTS-4) and aggrecanase 2 (ADAMTS-5) in cultured human chondrocytes. Moreover, β-cryptoxanthin was found to augment the gene expression of aggrecan core protein in chondrocytes. These results provide novel evidence that β-cryptoxanthin exerts anti-arthritic actions and suggest that β-cryptoxanthin may be useful in blocking the progression of rheumatoid arthritis and osteoarthritis.

Greater serum carotenoid concentration associated with higher bone mineral density in Chinese adults

This cross-sectional study has been performed to investigate the relationship between serum carotenoids and bone mineral density (BMD) in Chinese population. We found that women with higher serum β-cryptoxanthin, lycopene, or α-carotene exhibited higher BMD at various bone sites. Similar association was observed between α-carotene and BMD in men.

INTRODUCTION

Carotenoids may positively regulate bone metabolism through their antioxidant properties; however, few studies have examined the relation between serum carotenoids and bone health. We aimed to determine the associations between the serum concentration of several carotenoid subclasses and BMD in a Chinese population.

METHODS

This study was a community-based cross-sectional study. We measured 1898 women and 933 men aged 59.6 years who completed serum β-cryptoxanthin, zeaxanthin + lutein, lycopene, and α-carotene concentration analyses and BMD assessments. Serum individual carotenoids were assessed by the methods of reverse-phase high-performance liquid chromatography. Dual-energy X-ray absorptiometry was applied to determine BMD at whole body, lumbar spine, total hip, femur neck, and trochanter. ANCOVA was used to examine the correlations between categorized individual carotenoids and BMD at measured sites.

RESULTS

After adjusting for potential covariates, a monotonic dose-response positive correlation between circulating levels of β-cryptoxanthin, lycopene, and α-carotene and BMD at various skeletal sites was observed in women. Women in the top (vs. bottom) quartiles of serum β-cryptoxanthin, lycopene, or α-carotene exhibited 1.8-2.3, 1.5-2.0, or 1.3-2.7 % higher BMD at the bone sites with significant results (P-trend <0.05), respectively. For men, the corresponding values were 2.6-4.0 % for α-carotene at the whole body and hip regions (P-trend <0.001-0.023).

CONCLUSION

These results suggest that serum carotenoids have a favorable association with bone health in the study population, especially in women.

Ketocarotenoid Production in Soybean Seeds through Metabolic Engineering

The pink or red ketocarotenoids, canthaxanthin and astaxanthin, are used as feed additives in the poultry and aquaculture industries as a source of egg yolk and flesh pigmentation, as farmed animals do not have access to the carotenoid sources of their wild counterparts. Because soybean is already an important component in animal feed, production of these carotenoids in soybean could be a cost-effective means of delivery. In order to characterize the ability of soybean seed to produce carotenoids, soybean cv. Jack was transformed with the crtB gene from Pantoea ananatis, which codes for phytoene synthase, an enzyme which catalyzes the first committed step in the carotenoid pathway. The crtB gene was engineered together in combinations with ketolase genes (crtW from Brevundimonas sp. strain SD212 and bkt1 from Haematococcus pluvialis) to produce ketocarotenoids; all genes were placed under the control of seed-specific promoters. HPLC results showed that canthaxanthin is present in the transgenic seeds at levels up to 52 μg/g dry weight. Transgenic seeds also accumulated other compounds in the carotenoid pathway, such as astaxanthin, lutein, β-carotene, phytoene, α-carotene, lycopene, and β-cryptoxanthin, whereas lutein was the only one of these detected in non-transgenic seeds. The accumulation of astaxanthin, which requires a β-carotene hydroxylase in addition to a β-carotene ketolase, in the transgenic seeds suggests that an endogenous soybean enzyme is able to work in combination with the ketolase transgene. Soybean seeds that accumulate ketocarotenoids could potentially be used in animal feed to reduce or eliminate the need for the costly addition of these compounds.

Dietary Approaches for Bone Health: Lessons from the Framingham Osteoporosis Study

Osteoporosis is characterized by systemic impairment of bone mass, strength, and microarchitecture, resulting in increased risk for fragility fracture, disability, loss of independence, and even death. Adequate nutrition is important in achieving and maintaining optimal bone mass, as well as preventing this debilitating disease. It is widely accepted that adequate calcium and vitamin D intake are necessary for good bone health; however, nutritional benefits to bone go beyond these two nutrients. This review article will provide updated information on all nutrients and foods now understood to alter bone health. Specifically, this paper will focus on related research from the Framingham Osteoporosis Study, an ancillary study of the Framingham Heart Study, with data on more than 5000 adult men and women.

β-cryptoxanthin regulates bone resorption related-cytokine production in human periodontal ligament cells

OBJECTIVE

β-cryptoxanthin (β-cry) is a type of carotenoid found in certain fruits and vegetables. Although it has been shown that β-cry inhibits alveolar bone resorption, the molecular mechanisms for this have not yet been clarified. In the present study, we investigated the effects of β-cry on bone resorption related-cytokine production in human periodontal ligament (hPDL) cells.

DESIGN

hPDL cells were stimulated with β-cry (1×10(-7)mol/l), mechanical stress (1 or 6MPa), and P. gingivalis. The production of interleukin (IL)-1β, IL-6, IL-8, tumour necrosis factor (TNF)-α, osteoprotegerin (OPG), and receptor activator of nuclear factor kappa-B ligand (RANKL) were analyzed by RT-PCR and ELISA.

RESULTS

The production of IL-1β, IL-6, IL-8, and TNF-α was not induced in hPDL cells after stimulation with β-cry, although these cytokines were produced after stimulation with P. gingivalis. On the other hand, IL-6 and IL-8 were produced after exposure to 6MPa of mechanical stress. The production of IL-6 and IL-8 was significantly decreased by the addition of β-cry. Furthermore, β-cry up-regulated the production of OPG, but not RANKL.

CONCLUSION

β-cry inhibited the production of IL-6 and IL-8 induced by mechanical stress and periodontopathogenic bacteria in hPDL cells. Moreover, β-cry up-regulated OPG production. These results suggest that β-cry may prevent bone resorption in periodontitis.

High serum carotenoids associated with lower risk for bone loss and osteoporosis in post-menopausal Japanese female subjects: prospective cohort study

Introduction

Recent epidemiological studies show that high intakes of carotenoids might be useful to maintain bone health, but little is known about the association of serum carotenoids with change of bone mineral density (BMD). The objective of this study was to investigate longitudinally whether serum carotenoids are associated with bone loss.

Methods

We conducted a follow-up on 146 male and 99 pre- and 212 post-menopausal female subjects from the Mikkabi study. Those who participated in previous BMD surveys and completed four years of follow-up were examined longitudinally.

Results

During a 4-year follow-up, 15 of the post-menopausal female subjects developed new-onset osteoporosis. In contrast, none of the male and pre-menopausal female subjects did. In male and pre-menopausal female subjects, the six serum carotenoids at the baseline were not associated with bone loss. On the other hand, in post-menopausal female subjects, the 4-year bone loss of radius was inversely associated with the serum carotenoid concentrations, especially in β-carotene. After adjustments for confounders, the odds ratios (OR) for osteoporosis in the highest tertiles of serum β-carotene and β-cryptoxanthin against the lowest tertiles were 0.24 (95% confidence interval 0.05–1.21) and 0.07 (CI: 0.01–0.88), respectively. Serum β-cryptoxanthin was also inversely associated with the risk for osteopenia and/or osteoporosis (P for trend, 0.037). In addition, our retrospective analysis revealed that subjects who developed osteoporosis and/or osteopenia during the survey period had significantly lower serum concentrations of β-cryptoxanthin and β-carotene at the baseline than those in the normal group.

Conclusions

Antioxidant carotenoids, especially β-cryptoxanthin and β-carotene, are inversely associated with the change of radial BMD in post-menopausal female subjects.

Role of carotenoid β-cryptoxanthin in bone homeostasis

Bone homeostasis is maintained through a balance between osteoblastic bone formation and osteoclastic bone resorption. Aging induces bone loss due to decreased osteoblastic bone formation and increased osteoclastic bone resorption. Osteoporosis with its accompanying decrease in bone mass is widely recognized as a major public health problem. Nutritional factors may play a role in the prevention of bone loss with aging. Among various carotenoids (carotene and xanthophylls including beta (β)-cryptoxanthin, lutein, lycopene, β-carotene, astaxanthin, and rutin), β-cryptoxanthin, which is abundant in Satsuma mandarin orange (Citrus unshiu MARC.), has been found to have a stimulatory effect on bone calcification in vitro. β-cryptoxanthin has stimulatory effects on osteoblastic bone formation and inhibitory effects on osteoclastic bone resorption in vitro, thereby increasing bone mass. β-cryptoxanthin has an effect on the gene expression of various proteins that are related osteoblastic bone formation and osteoclastic bone resororption in vitro. The intake of β-cryptoxanthin may have a preventive effect on bone loss in animal models for osteoporosis and in healthy human or postmenopausal women. Epidemiological studies suggest a potential role of β-cryptoxanthin as a sustainable nutritional approach to improving bone health of human subjects. β-Cryptoxanthin may be an osteogenic factor in preventing osteoporosis in human subjects.

Dietary patterns of antioxidant vitamin and carotenoid intake associated with bone mineral density: findings from post-menopausal Japanese female subjects

Recent studies show that antioxidants may reduce the risk of osteoporosis. This study showed the associations of bone mineral density with dietary patterns of antioxidant vitamins and carotenoids. The findings suggest the combination of vitamin C and β-cryptoxanthin intakes might provide benefit to bone health in post-menopausal Japanese female subjects.

INTRODUCTION

Recent epidemiological studies show antioxidants may reduce the risk of osteoporosis, but little is known about the dietary patterns of antioxidant vitamin and carotenoid intakes and their relation with bone mineral density (BMD).

METHODS

A total of 293 post-menopausal female subjects who had received health examinations in the town of Mikkabi, Shizuoka Prefecture, Japan, participated in the study. Radial BMD was measured using dual-energy X-ray absorptiometry. Dietary intakes of antioxidant vitamins and carotenoids were assessed by using a validated food-frequency questionnaire. Dietary patterns were identified on a selected set of antioxidants through principal component factor analysis.

RESULTS

Three dietary patterns were identified. The "retinol" pattern, characterized by notably high intakes of preformed retinol, zeaxanthin, and vitamin E, was positively associated with the risk for low BMD. In contrast, the "β-cryptoxanthin" pattern, characterized by notably high intakes of β-cryptoxanthin and vitamin C, was negatively associated with low BMD. The odds ratios for low BMD in the highest tertiles of dietary intakes of preformed retinol, vitamin C, and β-cryptoxanthin against the lowest tertiles were 3.22 [95% confidence interval (CI), 1.38-7.51], 0.25 (CI, 0.10-0.66), and 0.40 (CI, 0.17-0.92), respectively, after adjustments for confounders. However, negative associations of vitamin C and β-cryptoxanthin with low BMD were not significant after further adjustment for intake of β-cryptoxanthin or vitamin C, respectively. Higher intakes of both vitamin C and β-cryptoxanthin were significantly associated with low BMD (P < 0.05).

CONCLUSIONS

The combination of vitamin C and β-cryptoxanthin may be associated with radial BMD in post-menopausal Japanese female subjects.

New hypotheses for the health-protective mechanisms of whole-grain cereals: what is beyond fibre?

Epidemiological studies have clearly shown that whole-grain cereals can protect against obesity, diabetes, CVD and cancers. The specific effects of food structure (increased satiety, reduced transit time and glycaemic response), fibre (improved faecal bulking and satiety, viscosity and SCFA production, and/or reduced glycaemic response) and Mg (better glycaemic homeostasis through increased insulin secretion), together with the antioxidant and anti-carcinogenic properties of numerous bioactive compounds, especially those in the bran and germ (minerals, trace elements, vitamins, carotenoids, polyphenols and alkylresorcinols), are today well-recognised mechanisms in this protection. Recent findings, the exhaustive listing of bioactive compounds found in whole-grain wheat, their content in whole-grain, bran and germ fractions and their estimated bioavailability, have led to new hypotheses. The involvement of polyphenols in cell signalling and gene regulation, and of sulfur compounds, lignin and phytic acid should be considered in antioxidant protection. Whole-grain wheat is also a rich source of methyl donors and lipotropes (methionine, betaine, choline, inositol and folates) that may be involved in cardiovascular and/or hepatic protection, lipid metabolism and DNA methylation. Potential protective effects of bound phenolic acids within the colon, of the B-complex vitamins on the nervous system and mental health, of oligosaccharides as prebiotics, of compounds associated with skeleton health, and of other compounds such as alpha-linolenic acid, policosanol, melatonin, phytosterols and para-aminobenzoic acid also deserve to be studied in more depth. Finally, benefits of nutrigenomics to study complex physiological effects of the 'whole-grain package', and the most promising ways for improving the nutritional quality of cereal products are discussed.

Protective effect of total carotenoid and lycopene intake on the risk of hip fracture: a 17-year follow-up from the Framingham Osteoporosis Study

In vitro and in vivo studies suggest that carotenoids may inhibit bone resorption, yet no previous study has examined individual carotenoid intake (other than beta-carotene) and the risk of fracture. We evaluated associations of total and individual carotenoid intake (alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, lutein + zeaxanthin) with incident hip fracture and nonvertebral osteoporotic fracture. Three hundred seventy men and 576 women (mean age, 75 +/- 5 yr) from the Framingham Osteoporosis Study completed a food frequency questionnaire (FFQ) in 1988-1989 and were followed for hip fracture until 2005 and nonvertebral fracture until 2003. Tertiles of carotenoid intake were created from estimates obtained using the Willett FFQ adjusting for total energy (residual method). HRs were estimated using Cox-proportional hazards regression, adjusting for sex, age, body mass index, height, total energy, calcium and vitamin D intake, physical activity, alcohol, smoking, multivitamin use, and current estrogen use. A total of 100 hip fractures occurred over 17 yr of follow-up. Subjects in the highest tertile of total carotenoid intake had lower risk of hip fracture (p = 0.02). Subjects with higher lycopene intake had lower risk of hip fracture (p =0.01) and nonvertebral fracture (p = 0.02). A weak protective trend was observed for total beta-carotene for hip fracture alone, but associations did not reach statistical significance (p = 0.10). No significant associations were observed with alpha-carotene, beta-cryptoxanthin, or lutein + zeaxanthin. These results suggest a protective role of several carotenoids for bone health in older adults.

Inverse association of carotenoid intakes with 4-y change in bone mineral density in elderly men and women: the Framingham Osteoporosis Study

BACKGROUND

In vitro and in vivo studies suggest that carotenoids may inhibit bone resorption and stimulate proliferation and differentiation of osteoblasts. Few studies have examined the association between carotenoid intake (other than beta-carotene) and bone mineral density (BMD).

OBJECTIVE

We evaluated associations between total and individual carotenoid intake (alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, and lutein+zeaxanthin) with BMD at the hip, spine, and radial shaft and the 4-y change in BMD.

DESIGN

Both cross-sectional and longitudinal analyses were conducted in 334 men and 540 women (mean +/- SD age: 75 +/- 5 y) in the Framingham Osteoporosis Study. Energy-adjusted carotenoid intakes were estimated from the Willett food-frequency questionnaire. Mean BMD and mean 4-y BMD changes were estimated, for men and women separately, by quartile of carotenoid intake with adjustment for age, BMI, height, physical activity index, smoking (never compared with ever smokers), multivitamin use, season of BMD measurement (for cross-sectional analyses on BMD only), estrogen use (in women), and intakes of total energy, calcium, vitamin D, caffeine, and alcohol.

RESULTS

Few cross-sectional associations were observed with carotenoid intake. Associations between lycopene intake and 4-y change in lumbar spine BMD were significant for women (P for trend = 0.03), as were intakes of total carotenoids, beta-carotene, lycopene and lutein+zeaxanthin with 4-y change in trochanter BMD in men (P for trend = 0.0005, 0.02, 0.009, and 0.008, respectively).

CONCLUSIONS

Carotenoids showed protective associations against 4-y loss in trochanter BMD in men and in lumbar spine in women. No significant associations were observed at other bone sites. Although not consistent across all BMD sites examined, these results support a protective role of carotenoids for BMD in older men and women.

Bone mineral density in post-menopausal female subjects is associated with serum antioxidant carotenoids

High intake of fruit and vegetables may reduce the risk of osteoporosis. Carotenoids exist in abundance in these foods. This study showed the association of bone mineral density with serum carotenoids. The findings suggest that beta-cryptoxanthin and beta-carotene might provide benefits to bone health in post-menopausal female subjects.

INTRODUCTION

Antioxidant carotenoids are abundant in fruit and vegetables. Recent epidemiological studies show that high intakes of fruit and vegetables may reduce the risk of osteoporosis, but little is known about the association of bone mineral density (BMD) with serum carotenoids.

METHODS

A total of 699 subjects (222 males and 477 females) who had received health examinations in the town of Mikkabi, Shizuoka Prefecture, Japan, participated in the study. Radial BMD was measured using dual-energy X-ray absorptiometry (DXA). The associations of serum carotenoid concentrations with the radial BMD were evaluated cross-sectionally.

RESULTS

In male and pre-menopausal female subjects, the six serum carotenoids were not associated with the radial BMD. On the other hand, in post-menopausal female subjects, serum beta-cryptoxanthin and beta-carotene were weakly but positively correlated with the radial BMD. After adjustment for confounders, the odds ratio (OR) for the lowest quartile of BMD in the high groups (Q2-Q4) of serum beta-cryptoxanthin against the lowest quartile (Q1) was 0.45 (95% confidence interval: 0.22-0.95) in post-menopausal female subjects. However, this association was not significant after further adjusting for intakes of minerals and vitamins.

CONCLUSIONS

Antioxidant carotenoids, especially beta-cryptoxanthin, significantly but partly associate with the radial BMD in post-menopausal female subjects.

Anabolic effect of beta-cryptoxanthin in osteoblastic MC3T3-E1 cells is enhanced with 17beta-estradiol, genistein, or zinc sulfate in vitro: the unique effect with zinc on Runx2 and alpha1(I) collagen mRNA expressions

Whether the anabolic effect of beta-cryptoxanthin (CRP), a kind of carotenoid, on osteoblastic MC3T3-E1 cells are modulated in the presence of various hormones or nutrient factors were investigated. Cells were cultured for 72 h in a minimum essential medium containing 10% fetal bovine serum (FBS), and the cells with subconfluency were changed to a medium containing either vehicle or CRP (10(-8)-10(-6) M) in the presence or absence of various factors without FBS. Cells were cultured for 72 h. Protein content or alkaline phosphatase activity in osteoblastic cells were significantly increased after culture with CRP (10(-7) or 10(-6) M), 1,25-dihydroxyvitamin D(3) (VD(3); 10(-9) or 10(-8) M), 17beta-estradiol (E(2); 10(-9) M), genistein (10(-7) or 10(-6) M), or menaquinone-7 (MK-7; 10(-7) or 10(-6) M). The effect of CRP (10(-6) M) in increasing protein content in the cells was significantly enhanced in the presence of E(2) (10(-9) M) or genistein (10(-6) M). Gene expression in osteoblastic cells was determined using reverse transcription-polymerase chain reaction (RT-PCR). Culture with CRP (10(-7) or 10(-6) M) caused a significant increase in the expression of Runx2 and alkaline phosphatase mRNAs in the cells. Runx2 mRNA expression was significantly increased after culture with E(2) (10(-9) M) or MK-7 (10(-7) or 10(-6) M), but not VD(3) (10(-9) or 10(-8) M) or genistein (10(-7) or 10(-6) M). Alkaline phosphatase mRNA expression was significantly increased after culture with VD(3) (10(-9) or 10(-8) M), genistein (10(-7) or 10(-6) M), or MK-7 (10(-7) or 10(-6) M), but not E(2) (10(-10) or 10(-9) M). The effect of CRP (10(-7) or 10(-6) M) in increasing Runx2 or alkaline phosphatase mRNA expressions in the cells was not enhanced in the presence of VD(3), E(2), genistein, or MK-7. Culture with zinc sulfate (zinc; 10(-5) M) caused a significant increase in protein content or alkaline phosphatase activity in osteoblastic cells. The effect of CRP (10(-7) M) in increasing protein content or alkaline phosphatase activity in the cells was not significantly enhanced in the presence of zinc (10(-5) M). Culture with zinc (10(-5) M) caused a significant increase in alpha1(I) collagen mRNA expression, while it did not have a significant effect on Runx2 or osteocalcin mRNA expressions in the cells. The effect of CRP (10(-7) M) in increasing Runx2 or alpha1(I) collagen mRNA expressions was significantly enhanced in the presence of zinc (10(-6 )or 10(-5) M). Such an effect was not seen in the presence of cycloheximide (10(-7) M), an inhibitor of protein synthesis, or 5,6-dichloro-1-beta-D: -ribofuranosyl-benzimidazole (DRB; 10(-6) M), an inhibitor of transcriptional activity. This study demonstrates that the stimulatory effect of CRP on protein content in osteoblastic cells was additively enhanced with E(2) or genistein, and that the stimulatory effect of CRP on Runx2 or alpha1(I) collagen mRNA expressions was enhanced in the presence of zinc. Thus, the anabolic effect of CRP in osteoblastic MC3T3-E1 cells was modulated with a specific factor.

Regulatory mechanism of food factors in bone metabolism and prevention of osteoporosis

Aging induces a decrease in bone mass, and osteoporosis with its accompanying decrease in bone mass is widely recognized as a major public health problem. Bone loss with increasing age may be due to decreased bone formation and increased bone resorption. Pharmacologic and nutritional factors may prevent bone loss with aging, although chemical compounds in food and plants which act on bone metabolism are poorly understood. We have found that isoflavones (including genistein and daidzein), which are contained in soybeans, have a stimulatory effect on osteoblastic bone formation and an inhibitory effect on osteoclastic bone resorption, thereby increasing bone mass. Menaquinone-7, an analogue of vitamin K(2) which is abundant in fermented soybeans, has been demonstrated to stimulate osteoblastic bone formation and to inhibit osteoclastic bone resorption. Of various carotenoids, beta-cryptoxanthin, which is abundant in Satsuma mandarin (Citrus unchiu MARC), has a stimulatory effect on osteoblastic bone formation and an inhibitory effect on osteoclastic bone resorption. The supplementation of these factors has a preventive effect on bone loss induced by ovariectomy in rats, which are an animal model of osteoporosis, and their intake has been shown to have a stimulatory effect on bone mass in humans. Factors with an anabolic effect on bone metabolism were found in extracts obtained from wasabi leafstalk (Wasabi japonica MATSUM), the marine alga Sargassum horneri, and bee pollen Cistus ladaniferus. Phytocomponent p-hydroxycinnamic acid was also found to have an anabolic effect on bone metabolism. Food chemical factors thus play a role in bone health and may be important in the prevention of bone loss with increasing age.

Beta-cryptoxanthin stimulates apoptotic cell death and suppresses cell function in osteoclastic cells: change in their related gene expression

The effect of beta-cryptoxanthin, a kind of carotenoid, on osteoclastic cells in mouse marrow culture system in vitro was investigated. The macrophage colony-stimulating factor (M-CSF)-dependent bone marrow macrophages were cultured in the presence of M-CSF (10 ng/ml) and receptor activator of NF-kappaB ligand (RANKL; 25 ng/ml) for 4 days. The osteoclastic cells formed were further cultured in medium containing either vehicle or beta-cryptoxanthin (10(-8)-10(-6) M) with or without M-CSF (10 ng/ml) and RANKL (50 ng/ml) for 24-72 h. Osteoclastic cells were significantly decreased with culture of beta-cryptoxanthin (10(-7) or 10(-6) M) with or without M-CSF and RANKL for 24, 48, or 72 h. beta-Cryptoxanthin (10(-8) M)-induced decrease in osteoclastic cells were significantly inhibited in the presence of caspase-3 inhibitor (10(-8) or 10(-7) M). Agarose gel electrophoresis showed the presence of low-molecular-weight deoxyribonucleic acid (DNA) fragments of adherent cells cultured with beta-cryptoxanthin (10(-7) or 10(-6) M) for 24 or 48 h, indicating that the carotenoid induces apoptotic cell death. Apoptosis-related gene expression was determined using reverse transcription-polymerase chain reaction (RT-PCR). Culture with beta-cryptoxanthin (10(-7) or 10(-6) M) for 24 or 48 h caused a significant increase in caspase-3 mRNA expression in the presence or absence of M-CSF and RANKL, while Bcl-2 and Apaf-2 mRNA expressions were significantly increased with culture of beta-cryptoxanthin (10(-7) or 10(-6) M) without M-CSF and RANKL for 24 or 48 h. Akt-1 mRNA expression was not significantly changed with culture of the carotenoid (10(-7) or 10(-6) M) for 24 or 48 h. Moreover, tartrate-resistant acid phosphatase (TRACP) activity, or TRACP and cathepsin K mRNA expressions were significantly decreased with culture of beta-cryptoxanthin (10(-6) M) in the presence or absence of M-CSF and RANKL for 48 h. This study demonstrates that beta-cryptoxanthin has stimulatory effects on apoptotic cell death and suppressive effects on osteoclastic cell function.

Oral Administration in Combination with Zinc Enhances .BETA.-Cryptoxanthin-Induced Anabolic Effects on Bone Components in the Femoral Tissues of Rats in Vivo

The effects of combined beta-cryptoxanthin and zinc on bone components in the femoral-diaphyseal (cortical bone) and -metaphyseal (trabecular bone) tissues of rats in vivo were investigated. Rats were orally administered either vehicle, beta-cryptoxanthin (5 or 10 microg/100 g body weight), zinc sulfate (0.1 or 0.5 mg Zn/100 g), or their combination once a day for 7 d. Calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal tissues was not significantly altered by the administration of beta-cryptoxanthin (5 microg/100 g) or zinc (0.1 or 0.5 mg/100 g). Combined administration of beta-cryptoxanthin (5 microg/100 g) and zinc (0.1 or 0.5 mg/100 g) caused a synergistic increase in calcium content, alkaline phosphatase activity, and DNA content in the diaphyseal tissues. The effect of beta-cryptoxanthin (5 or 10 microg/100 g) in increasing calcium and DNA contents in the metaphyseal tissues was significantly enhanced by the combined administration of zinc (0.1 or 0.5 mg/100 g), but did not have a significant effect on the metaphyseal components. The metaphyseal alkaline phosphatase activity was markedly increased by the combination of beta-cryptoxanthin (5 microg/100 g) and zinc (0.1 or 0.5 mg/100 g). This study demonstrates that the oral administration of the combination of zinc at lower doses synergistically enhances beta-cryptoxanthin-induced anabolic effects on bone components in the femoral tissues of rats in vivo.

beta-cryptoxanthin stimulates cell differentiation and mineralization in osteoblastic MC3T3-E1 cells

The effect of beta-cryptoxanthin, a kind of carotenoid, on cell differentiation and mineralization in osteoblastic MC3T3-E1 cells was investigated. Cells were cultured for 72 h in a minimum essential medium containing 10% fetal bovine serum (FBS), and the cells with subconfluency were changed to a medium containing either vehicle or beta-cryptoxanthin (10(-8) to 10(-6) M) without FBS. Cells were cultured for 3 to 21 days. Gene expression in osteoblastic cells was determined using reverse transcription-polymerase chain reaction (RT-PCR). Culture with beta-cryptoxanthin (10(-7) or 10(-6) M) for 3 days caused a significant increase in Runx2 type 1, Runx2 type 2, alpha1 (I) collagen, and alkaline phosphatase mRNA levels in osteoblastic cells. These increases were completely blocked in the presence of cycloheximide, an inhibitor of protein synthesis, or 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB), an inhibitor of transcriptional activity. Meanwhile, vitamin A (10(-6) M) did not have a significant effect on Runx2 type 1 mRNA expression in the cells. The effect of beta-cryptoxanthin (10(-6) M) in stimulating Runx2 type 1 and alpha1 (I) collagen mRNA levels, protein content, and alkaline phosphatase activity in the cells was also seen in the presence of vitamin A (10(-6) M), suggesting that the mode of beta-cryptoxanthin action differs from that of vitamin A. Prolonged culture with beta-cryptoxanthin (10(-6) M) for 3 to 21 days caused a significant increase in cell number, deoxyribonucleic acid (DNA) content, protein content, and alkaline phosphatase activity in osteoblastic cells, suggesting that beta-cryptoxanthin stimulates cell proliferation and differentiation. Moreover, culture with beta-cryptoxanthin (10(-7) or 10(-6) M) for 5 to 21 days caused a remarkable increase in mineralization. This study demonstrates that beta-cryptoxanthin has a stimulatory effect on cell differentiation and mineralization due to enhancing gene expression of proteins, which involve in bone formation in osteoblastic MC3T3-E1 cells.

Synergistic effect of beta-cryptoxanthin and zinc sulfate on the bone component in rat femoral tissues in vitro: the unique anabolic effect with zinc

The effect of the combination of beta-cryptoxanthin and zinc sulfate (zinc) on bone components in the femoral-diaphyseal and -metaphyseal tissues of young rats in vitro was investigated. Bone tissues were cultured for 48 h in a serum-free Dulbecco's modified Eagle's medium containing either vehicle, beta-cryptoxanthin (10(-9)-10(-7) M) or zinc sulfate (10(-6)-10(-4) M). The presence of beta-cryptoxanthin (10(-9) M) or zinc (10(-6) M) did not have a significant effect on calcium content in the femoral-diaphyseal or -metaphyseal tissues. However, culture which combined beta-cryptoxanthin (10(-9) M) and zinc (10(-6) M) caused a significant increase in calcium content in the femoral-diaphyseal and -metaphyseal tissues. Such an effect was not observed by the combination of beta-cryptoxanthin (10(-9) M) plus genistein (10(-6) M) or menaquinone-7 (10(-6) M), or zinc (10(-6) M) plus genistein (10(-6) M) or menaquinone-7 (10(-6) M). Also, the combination of beta-cryptoxanthin (10(-9) M) plus zinc (10(-6) M) caused a remarkable increase in alkaline phosphatase activity and deoxyribonucleic acid (DNA) in the femoral-diaphyseal and -metaphyseal tissues, while their application alone did not have an effect on the enzyme activity or DNA content in the femoral tissues. The effect of the combination of beta-cryptoxanthin (10(-9) M) plus zinc (10(-6) M) in increasing calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal and -metaphyseal tissues was completely prevented in the presence of cycloheximide (10(-6) M), an inhibitor of protein synthesis, or 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DBR), an inhibitor of transcriptional activity. This study demonstrates that the combination of beta-cryptoxanthin and zinc at a lower concentration has a synergistic effect on bone components in vitro.

Oral Administration of .BETA.-Cryptoxanthin Prevents Bone Loss in Streptozotocin-Diabetic Rats in Vivo

The effects of beta-cryptoxanthin, a carotenoid, on bone components in the femoral-diaphyseal and -metaphyseal tissues of streptozotocin (STZ)-diabetic rats was investigated. Rats received a single subcutaneous administration of STZ (6.0 mg/100 g body weight), and then the animal were orally administered beta-cryptoxanthin (5 or 10 microg/100 g body weight) once daily for 7 or 14 d. The administration of STZ caused a significant decrease in body weight and a significant increase in serum glucose, triglyceride, and calcium levels, indicating a diabetic state. These alterations were significantly prevented by the administration of beta-cryptoxanthin (5 or 10 microg/100 g) for 14 d. The administration of beta-cryptoxanthin (5 or 10 microg/100 g) to normal rats for 14 d did not have a significant effect on body weight or on serum glucose, triglyceride, and calcium levels. Calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal and -metaphyseal tissues were significantly decreased in STZ-diabetic rats. These decreases were significantly prevented by the administration of beta-cryptoxanthin (5 or 10 microg/100 g) for 14 d. The administration of beta-cryptoxanthin to normal rats for 14 d caused a significant increase in calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal and -metaphyseal tissues. This study demonstrates that the intake of beta-cryptoxanthin has a preventive effect on bone loss in STZ-diabetic rats.