Monthly Archives: August 2013

Ukrain No Benefit in Rats

Abstract

Effect of intermittent three-month treatment with different doses of Ukrain on subregional femoral bone mineral density of sexually mature female rats.

Sexually mature but still growing female Wistar rats received i.p. injections of Ukrain (7, 14 or 28 mg/kg in a volume of 0.5 ml/100g) every other day for 10 days, followed by a 10-day break, and this procedure was performed five times. The control animals received the same volume of injected water. At the end of the experiment the rat right femora were harvested and the bone densitometric parameters of the entire bone, distal metaphyseal and basicervical subregions were assessed using the dual-energy X-ray absorptiometry (DXA) densitometric method. No significant changes were observed in the bone mineral density in experimental groups in comparison with control animals that received the vehicle. A slight decrease in the bone mineral content value was observed in the distal metaphyseal region in animals that were treated with the highest dose of Ukrain.

Gorzelak M, Jabłoński M, Patyra M, Jagiello-Wójtowicz E
Drugs Exp Clin Res 1998
PMID: 10190094

Ukrain Prevents Bone Loss in Rats

Abstract

Effect of six-month treatment with Ukrain on early osteoporosis induced by ovariectomy in rats. Part I: Preliminary studies of bone parameters.

Ukrain, thiophosphoric acid alkaloid derivatives from Chelidonium majus L. was administered intraperitoneally in a dose of 28 mg/kg (equivalent to 0.1 LD50) every other day for six months to female rats with ovariectomy-induced early osteoporosis. Administration of Ukrain was started on the second day after the surgical operation. At the end of the long-term treatment with Ukrain each rat was tested for the strength of both humeri and some parameters of rat femur were measured. The body weight of ovariectomized rats was also examined. The present results show that the decrease in the mechanical strength of the humeral bones and some changes in the femur caused by ovariectomy were prevented by the six-month treatment with Ukrain. However, in both ovariectomized groups and in ovariectomized rats pretreated with Ukrain an increase of body weight was observed.

Jagiełło-Wojtowicz E, Kleinrok Z, Nowicky JW, Jabłonski M…
Drugs Exp Clin Res 1996
PMID: 8899324

Vitamin C is a Skeletal Anabolic Agent in Mice

Abstract

Vitamin C prevents hypogonadal bone loss.

Epidemiologic studies correlate low vitamin C intake with bone loss. The genetic deletion of enzymes involved in de novo vitamin C synthesis in mice, likewise, causes severe osteoporosis. However, very few studies have evaluated a protective role of this dietary supplement on the skeleton. Here, we show that the ingestion of vitamin C prevents the low-turnover bone loss following ovariectomy in mice. We show that this prevention in areal bone mineral density and micro-CT parameters results from the stimulation of bone formation, demonstrable in vivo by histomorphometry, bone marker measurements, and quantitative PCR. Notably, the reductions in the bone formation rate, plasma osteocalcin levels, and ex vivo osteoblast gene expression 8 weeks post-ovariectomy are all returned to levels of sham-operated controls. The study establishes vitamin C as a skeletal anabolic agent.

Zhu LL, Cao J, Sun M, Yuen T…
PLoS ONE 2012
PMID: 23056580 | Free Full Text

Vitamin C Supplements Associated With Bone Density in Postmenopausal Women

Abstract

Vitamin C supplement use and bone mineral density in postmenopausal women.

Vitamin C is known to stimulate procollagen, enhance collagen synthesis, and stimulate alkaline phosphatase activity, a marker for osteoblast formation. Studies of dietary vitamin C intake and the relation with bone mineral density (BMD) have been conflicting, probably because of the well-known limitations of dietary nutrient assessment questionnaires. The purpose of this study was to evaluate the independent relation of daily vitamin C supplement use with BMD in a population-based sample of postmenopausal women. Subjects were 994 women from a community-based cohort of whom 277 women were regular vitamin C supplement users. Vitamin C supplement use was validated. Daily vitamin C supplement intake ranged from 100 to 5,000 mg; the mean daily dose was 745 mg. Average duration of use was 12.4 years; 85% had taken vitamin C supplements for more than 3 years. BMD levels were measured at the ultradistal and midshaft radii, hip, and lumbar spine. After adjusting for age, body mass index (BMI), and total calcium intake, vitamin C users had BMD levels approximately 3% higher at the midshaft radius, femoral neck, and total hip (p < 0.05). In a fully adjusted model, significant differences remained at the femoral neck (p < 0.02) and marginal significance was observed at the total hip (p < 0.06). Women taking both estrogen and vitamin C had significantly higher BMD levels at all sites. Among current estrogen users, those also taking vitamin C had higher BMD levels at all sites, with marginal significance achieved at the ultradistal radius (p < 0.07), femoral neck (p < 0.07), and total hip (p < 0.09). Women who took vitamin C plus calcium and estrogen had the highest BMD at the femoral neck (p = 0.001), total hip (p = 0.05), ultradistal radius (p = 0.02), and lumbar spine. Vitamin C supplement use appears to have a beneficial effect on levels of BMD, especially among postmenopausal women using concurrent estrogen therapy and calcium supplements.

Morton DJ, Barrett-Connor EL, Schneider DL
J. Bone Miner. Res. Jan 2001
PMID: 11149477

Antioxidants No Benefit in Population Study, Except Vitamin C with HRT

Abstract

Lack of a relation between vitamin and mineral antioxidants and bone mineral density: results from the Women’s Health Initiative.

Antioxidant defenses are one possible mechanism for decreasing oxidative damage and its potentially negative effects on age-related bone mass.
This study cross-sectionally examined whether higher dietary intakes, total intakes, and serum concentrations of antioxidants may be associated with higher bone mineral density (BMD).
Total hip (and subregions), spine, and total-body BMDs were measured in 11,068 women aged 50-79 y enrolled in the Women’s Health Initiative Observational Study and Clinical Trial at 3 clinics. Antioxidant intakes from diet (vitamin A, retinol, beta-carotene, vitamin C, vitamin E, and selenium) were estimated by using a self-reported food-frequency questionnaire. Antioxidants from supplements were estimated with an interviewer-administered questionnaire. A random subset (n = 379) had serum concentrations of retinol, carotenoids, and tocopherols measured.
After adjustment for important BMD-related covariates, increasing intakes of antioxidants were not independently associated with BMD. A significant interaction effect was observed between intake of total vitamin C (lower three-fourths compared with highest one-fourth) and use of hormone therapy (HT) (P < 0.01). The beneficial effect of current HT use on femoral neck BMD appeared to be greater in women with higher concentrations of total vitamin C. This interaction was also significant for total-body (P < 0.045), spine (P = 0.03), and total-hip BMDs (P = 0.029).
Our results do not support independent associations between dietary intake, total intake, or serum concentrations of antioxidants and BMD in women participating in the Women’s Health Initiative. The extent to which HT use may interact with vitamin C intake and BMD warrants further exploration.

Wolf RL, Cauley JA, Pettinger M, Jackson R…
Am. J. Clin. Nutr. Sep 2005
PMID: 16155271 | Free Full Text

Vitamin C Effects Not Clear in Population Study

Abstract

Relation of ascorbic acid to bone mineral density and self-reported fractures among US adults.

Ascorbic acid is an essential nutrient involved in collagen formation, and its deficiency is associated with abnormal bone development. To examine the relation of ascorbic acid to bone mineral density and the prevalence of self-reported fractures, the authors analyzed data collected from 13,080 adults enrolled in the Third National Health and Nutrition Examination Survey (NHANES III) during 1988-1994. Because they identified three-way interactions among smoking, history of estrogen use, and dietary and serum ascorbic acid in postmenopausal women, they analyzed these relations stratified by smoking and estrogen use. Dietary ascorbic acid intake was independently associated with bone mineral density among premenopausal women (p = 0.002). Among men, serum ascorbic acid was associated in a nonlinear fashion with bone mineral density (p < 0.05), and dietary ascorbic acid intake was associated in a nonlinear fashion with self-reported fracture (p = 0.05). Among postmenopausal women without a history of smoking or estrogen use, serum ascorbic acid was unexpectedly associated with lower bone mineral density (p = 0.01). However, among postmenopausal women with a history of smoking and estrogen use, a standard deviation increase in serum ascorbic acid was associated with a 49% decrease in fracture prevalence (p = 0.001). Dietary and serum ascorbic acid measures were associated inconsistently with bone mineral density and self-reported fracture among adult participants in NHANES III.

Simon JA, Hudes ES
Am. J. Epidemiol. Sep 2001
PMID: 11532784 | Free Full Text

Saturated Fat Associated with Lower Bone Density; Protein or Vitamin C No Help

Abstract

Dietary saturated fat intake is inversely associated with bone density in humans: analysis of NHANES III.

Mounting evidence indicates that the amount and type of fat in the diet can have important effects on bone health. Most of this evidence is derived from animal studies. Of the few human studies that have been conducted, relatively small numbers of subjects and/or primarily female subjects were included. The present study assessed the relation of dietary fat to hip bone mineral density (BMD) in men and women using NHANES III data (n = 14,850). Multivariate models using SAS-callable SUDAAN were used to adjust for the sampling scheme. Models were adjusted for age, sex, weight, height, race, total energy and calcium intakes, smoking, and weight-bearing exercise. Data from women were further adjusted for use of hormone replacement therapy. Including dietary protein, vitamin C, and beta-carotene in the model did not influence the outcome. Analysis of covariance was used to generate mean BMD by quintile of total and saturated fat intake for 4 sex/age groups. Saturated fat intake was negatively associated with BMD at several hip sites. The greatest effects were seen among men < 50 y old (linear trend P = 0.004 for the femoral neck). For the femoral neck, adjusted mean BMD was 4.3% less among men with the highest compared with the lowest quintile of saturated fat intake (BMD, 95% CI: highest quintile: 0.922 g/cm2, 0.909-0.935; lowest quintile: 0.963 g/cm2, 95% CI: 0.950-0.976). These data indicate that BMD is negatively associated with saturated fat intake, and that men may be particularly vulnerable to these effects.

Corwin RL, Hartman TJ, Maczuga SA, Graubard BI
J. Nutr. Jan 2006
PMID: 16365076 | Free Full Text

Vitamins C + E, or Exercise, Prevent Bone Loss in Women

Abstract

Effect of antioxidants combined to resistance training on BMD in elderly women: a pilot study.

We determined the effect of antioxidants and resistance training on bone mineral density of postmenopausal women. After 6 months, we observed a significant decrease in the lumbar spine BMD of the placebo group while other groups remained stable. Antioxidants may offer protection against bone loss such as resistance training.
The purpose of this pilot study was to determine the effects of antioxidant supplements combined to resistance training on bone mineral density (BMD) in healthy elderly women.
Thirty-four postmenopausal women (66.1 +/- 3.3 years) were randomized in four groups (placebo, n = 7; antioxidants, n = 8; exercise and placebo, n = 11; and exercise and antioxidants, n = 8). The 6-month intervention consisted in antioxidant supplements (600 mg vitamin E and 1,000 mg vitamin C daily) or resistance exercise (3x/week). Femoral neck and lumbar spine BMD (DXA) and dietary intakes (3-day food record) were measured before and after the intervention. A repeated measure ANOVA and non-parametric Mann-Whitney U tests were used.
We observed a significant decrease in the placebo group for lumbar spine BMD (pre, 1.01 +/- 0.17 g/cm(2); post, 1.00 +/- 0.16 g/cm(2); P < 0.05 respectively) while it remained stable in all other groups. No changes were observed for femoral neck BMD.
Antioxidant vitamins may offer some protection against bone loss in the same extent as resistance exercise although combining both does not seem to produce additional effects. Our results suggest to further investigate the impact of antioxidant supplements on the prevention of osteoporosis.

Chuin A, Labonté M, Tessier D, Khalil A…
Osteoporos Int Jul 2009
PMID: 19020919

Vitamin C Inhibits Osteoclasts in Rats Fed a High-Cholesterol Diet

Abstract

Vitamin C intake inhibits serum lipid peroxidation and osteoclast differentiation on alveolar bone in rats fed on a high-cholesterol diet.

A high-cholesterol diet stimulates osteoclast differentiation, which may be induced by increased serum lipid peroxidation. The inhibition of serum lipid peroxidation by vitamin C may offer beneficial effects on osteoclast differentiation including increased expression of receptor activator of nuclear factor (NF)-kappaB ligand (RANKL) and NF-kappaB. This study investigated the effects of vitamin C intake on RANKL and NF-kappaB expression in periodontal tissue of rats fed a high-cholesterol diet.
Twenty-four rats (8 weeks old) were divided into four groups: a control group (fed a regular diet) and three experimental groups (fed a high-cholesterol diet supplemented with 0, 1 and 2 g/l vitamin C/day) in this 12-week study. Vitamin C was provided by its addition to drinking water. As an index of serum lipid peroxidation, hexanoyl-lysine (HEL) level was determined by a competitive enzyme-linked immunosorbent assay method. Immunohistological analysis was performed to evaluate RANKL and NF-kappaB expression on the alveolar bone surface. The number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts was also counted.
Feeding a high-cholesterol diet increased not only the serum HEL level but also the number of TRAP-positive osteoclasts on the alveolar bone surface, with an increase in RANKL and NF-kappaB expression on alveolar bone surface. Intake of vitamin C reduced the serum HEL level and osteoclast differentiation, with decreasing RANKL and NF-kappaB expression.
Vitamin C intake could suppress osteoclast differentiation, including RANKL and NF-kappaB expression on the alveolar bone surface, by decreasing serum lipid peroxidation in rats fed a high-cholesterol diet.

Sanbe T, Tomofuji T, Ekuni D, Azuma T…
Arch. Oral Biol. Mar 2009
PMID: 19110235

Vitamin C Increases Collagen Synthesis of Osteoblasts

Abstract

Rab GTPase mediated procollagen trafficking in ascorbic acid stimulated osteoblasts.

Despite advances in investigating functional aspects of osteoblast (OB) differentiation, especially studies on how bone proteins are deposited and mineralized, there has been little research on the intracellular trafficking of bone proteins during OB differentiation. Collagen synthesis and secretion is the major function of OBs and is markedly up-regulated upon ascorbic acid (AA) stimulation, significantly more so than in fibroblast cells. Understanding the mechanism by which collagen is mobilized in specialized OB cells is important for both basic cell biology and diseases involving defects in bone protein secretion and deposition. Protein trafficking along the exocytic and endocytic pathways is aided by many molecules, with Rab GTPases being master regulators of vesicle targeting. In this study, we used microarray analysis to identify the Rab GTPases that are up-regulated during a 5-day AA differentiation of OBs, namely Rab1, Rab3d, and Rab27b. Further, we investigated the role of identified Rabs in regulating the trafficking of collagen from the site of synthesis in the ER to the Golgi and ultimately to the plasma membrane utilizing Rab dominant negative (DN) expression. We also observed that experimental halting of biosynthetic trafficking by these mutant Rabs initiated proteasome-mediated degradation of procollagen and ceased global protein translation. Acute expression of Rab1 and Rab3d DN constructs partially alleviated this negative feedback mechanism and resulted in impaired ER to Golgi trafficking of procollagen. Similar expression of Rab27b DN constructs resulted in dispersed collagen vesicles which may represent failed secretory vesicles sequestered in the cytosol. A significant and strong reduction in extracellular collagen levels was also observed implicating the functional importance of Rab1, Rab3d and Rab27b in these major collagen-producing cells.

Nabavi N, Pustylnik S, Harrison RE
PLoS ONE 2012
PMID: 23050002 | Free Full Text