Tag Archives: free full text

Lactosucrose Enhances Calcium Absorption in Young Women

Abstract

Long-term administration of 4G-beta-D-galactosylsucrose (lactosucrose) enhances intestinal calcium absorption in young women: a randomized, placebo-controlled 96-wk study.

This study determined the effect of long-term administration of 4(G)-beta-D-galactosylsucrose (lactosucrose; LS) on intestinal calcium absorption. In a randomized, single-blind, parallel-group study, LS (n=9, 6.0 g twice daily) or a placebo (maltose; n=8, 6.0 g twice daily) was administered to healthy young women for 92 wk: the study also included a 4-wk post-administration period. All participants completed the study. Dietary nutrient intake; fecal weight, pH, and moisture content; fecal concentrations of short-chain fatty acids (SCFA), putrefactive products, ammonia, and minerals (calcium, magnesium, phosphorus, and iron); and serum calcium and osteocalcin concentrations were measured every 24 wk. Urinary pyridinoline (PYR) and deoxypyridinoline (DPD), and urinary calcium excretion were measured every 12 wk. Significant effects of oligosaccharide treatment, time, and the interaction between oligosaccharide treatment and time were observed for fecal pH, SCFA, ammonia, and putrefactive product values (p<0.05). Fecal pH, ammonia, and putrefactive product values decreased in the LS group, and the fecal SCFA concentration significantly increased during the administration period; these changes were not observed 4 wk post-administration. To examine the mineral balance of calcium, magnesium, and phosphorus in detail, all the participants completed a 6-d mineral balance study, sometime between week 56 and 60 of the longer study. During the mineral balance study, the daily calcium intake was set at 400 mg; all feces and urine were collected each day for 6 d after an 8-d acclimation period. In the balance study, fecal calcium excretion was significantly lower in the LS group than in the placebo group (p<0.05), and apparent calcium absorption and retention, apparent magnesium and phosphorus absorption, and magnesium retention were significantly higher in the LS group than in the placebo group (p<0.05). Our results suggest that the administration of LS produces a long-term enhancement of intestinal calcium absorption in healthy young women with lower than recommended calcium intakes.

Teramoto F, Rokutan K, Sugano Y, Oku K…
J. Nutr. Sci. Vitaminol. Oct 2006
PMID: 17190104 | Free Full Text

BMD did not differ between groups.

The lack of change in BMD might have been influenced by enhanced intestinal phosphorus absorption as a consequence of the enhanced intestinal calcium absorption during LS administration.

The insufficient calcium intake, age of the participants, ratio of calcium to phosphorus in the diet, and changes in LS administration may have influenced BMD.

Review: Statins and Bone Formation

Abstract

Statins, bone formation and osteoporosis: hope or hype?

Osteoporosis is a major health problem affecting both men and women. Statins, besides their action as lipid-lowering agents, seem to have additional pleiotropic properties, among them a beneficial effect on bone mineral density. The entirety of experimental and the majority of clinical studies as well as the only relevant meta-analysis suggest that statins have an anabolic effect on bone metabolism. Statins, osteoporosis and adipogenesis share the same pathway, RANKL/OPG. It would appear that an imbalance in this pathway could be responsible for the manifestation of some metabolic disorders such as diabetes mellitus, atherogenesis, multiple myeloma, osteoporosis. Possibly in the future, drugs which can intervene in this biochemical and pathophysiological cascade, like statins, in a variety of doses, could be used for the management of ectopic ossification syndromes and other bone disorders, even as an additive treatment. Until then, further large longitudinal randomized controlled studies for each statin separately are required to confirm this hypothesis.

Tsartsalis AN, Dokos C, Kaiafa GD, Tsartsalis DN…
Hormones (Athens)
PMID: 22801558 | Free Full Text

All the available data from the literature, including evidence from experimental studies as well as from the vast majority of observational studies and the results of a single meta-analysis, suggested that there is a positive effect of statins on BMD, although another meta-analysis by Bauer et al72 showed evidence that the beneficial effects on BMD and on fracture risk are observational, while many limitations and the placebo-controlled trials did not demonstrate any clear-cut benefit. However, the in vitro and some clinical studies (Chuengsamarn et al71) suggest that statins inhibit bone resorption and stimulate bone formation, having a dual action on bone metabolism. Therefore, in the future statins might gain a position among drugs used for the prevention and management of osteoporosis, taking into account that clinicians already have a good deal of experience in prescribing statins, for other indications, and feel familiar with this drug family. Their anabolic and anti-resorptive effects on bone make them an ideal candidate for osteoporosis treatment.

Simvastatin Intensifies Bone Formation and Decreases Resorption in Ovariectomized Rats

Abstract

Effects of simvastatin on the development of osteopenia caused by ovariectomy in rats.

Simvastatin is a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, the rate-determining enzyme for cholesterol synthesis which is used in the treatment of hypercholesterolemias, particularly in type IIa and IIb hyperlipoproteinemias, frequently in postmenopausal women. Inhibition of cholesterol synthesis by simvastatin may cause disorders of bone remodelling. The aim of the present study was to investigate the effects of simvastatin (3 mg and 6 mg/kg/day per os) administered for 4 weeks on the development of ovariectomy-induced osteopenia in 3-month-old female Wistar rats. The experiments were carried out on six groups of animals: I (C)–sham operated rats, II (S-3)–sham operated rats + simvastatin 3 mg/kg/day p.o., III (S-6)–sham operated rats + simvastatin 6 mg/kg/day p.o., IV (OVX)–ovariectomized rats, V (OVX + S-3)–ovariectomized rats + simvastatin 3 mg/kg/day p.o., VI (OVX + S-6)–ovariectomized rats + simvastatin 6 mg/kg/day p.o. In all the groups, we examined body weight gain, and macrometrical, histomorphometrical and mechanical parameters. Bilateral ovariectomy induced osteopenic skeletal changes in mature female rats. In cortical bone, ovariectomy intensified resorption processes at the marrow cavity, as indicated by a decrease in endosteal transverse growth and an increase in transverse cross-section surface area of the marrow cavity in the tibia. Intensification of resorption processes was observed in cancellous bone (a statistically significant decrease in the width of trabeculae in the epiphysis and metaphysis of the femur). Structural changes in the long bones resulting from bilateral ovariectomy were manifested by deterioration of mechanical properties of the shaft and neck of the femur. The force needed to fracture the neck and shaft of the femur was significantly smaller than that in sham operated rats. Simvastatin (3 and 6 mg/kg/day p.o.) slightly influenced bone remodelling in sham operated rats. Simvastatin (3 and 6 mg/kg p.o. daily) administered to ovariectomized rats intensified bone formation processes and decreased bone resorption processes induced by bilateral ovariectomy, showing stronger activity at 6 mg/kg.

Pytlik M, Janiec W, Misiarz-Myrta M, Gubała I
Pol J Pharmacol
PMID: 12856828 | Free Full Text

EPA + DHA: Possible Mechanism

Abstract

PTH1 receptor is involved in mediating cellular response to long-chain polyunsaturated fatty acids.

The molecular pathways by which long chain polyunsaturated fatty acids (LCPUFA) influence skeletal health remain elusive. Both LCPUFA and parathyroid hormone type 1 receptor (PTH1R) are known to be involved in bone metabolism while any direct link between the two is yet to be established. Here we report that LCPUFA are capable of direct, PTH1R dependent activation of extracellular ligand-regulated kinases (ERK). From a wide range of fatty acids studied, varying in chain length, saturation, and position of double bonds, eicosapentaenoic (EPA) and docosahexaenoic fatty acids (DHA) caused the highest ERK phosphorylation. Moreover, EPA potentiated the effect of parathyroid hormone (PTH(1-34)) in a superagonistic manner. EPA or DHA dependent ERK phosphorylation was inhibited by the PTH1R antagonist and by knockdown of PTH1R. Inhibition of PTH1R downstream signaling molecules, protein kinases A (PKA) and C (PKC), reduced EPA and DHA dependent ERK phosphorylation indicating that fatty acids predominantly activate G-protein pathway and not the β-arrestin pathway. Using picosecond time-resolved fluorescence microscopy and a genetically engineered PTH1R sensor (PTH-CC), we detected conformational responses to EPA similar to those caused by PTH(1-34). PTH1R antagonist blocked the EPA induced conformational response of the PTH-CC. Competitive binding studies using fluorescence anisotropy technique showed that EPA and DHA competitively bind to and alter the affinity of PTH1 receptor to PTH(1-34) leading to a superagonistic response. Finally, we showed that EPA stimulates protein kinase B (Akt) phosphorylation in a PTH1R-dependent manner and affects the osteoblast survival pathway, by inhibiting glucocorticoid-induced cell death. Our findings demonstrate for the first time that LCPUFAs, EPA and DHA, can activate PTH1R receptor at nanomolar concentrations and consequently provide a putative molecular mechanism for the action of fatty acids in bone.

Candelario J, Tavakoli H, Chachisvilis M
PLoS ONE 2012
PMID: 23300710 | Free Full Text

In human studies, it has been shown that consuming EPA improved bone quality in elderly female subjects [21]. Consumption of ω-3 fatty acids was also associated with reduced incidence and severity of inflammatory bone/joint diseases in humans [22]. There is evidence of the potential of EPA to counteract bone loss associated with spaceflight; higher consumption of fish (ω-3) was associated with reduced loss of bone mineral density (BMD) after flight [23]. BMD of the total body showed a significant negative correlation with serum concentrations of oleic acids and monounsaturated fatty acids and significant correlations with DHA and ω-3 fatty acids [24]. A higher ratio of ω-6 to ω-3 fatty acids is associated with lower BMD at the hip in both sexes suggesting the relative amounts of dietary PUFA may play a vital role in preserving skeletal integrity in older age [25].

Nutrients Correlated With Bone Density

Abstract

[Validation of questionnaires for the study of food habits and bone mass].

The loss of bone mass and density is influenced by nutritional factors that act on the bone mass peak, age-related bone loss and muscle strength. The objective of the present study was to validate a food frequency questionnaire applied to estimate the relationship between food habits and bone mineral density (BMD) in a healthy adult population.
The results of the food frequency questionnaire were compared with 24-hr recall findings. Calcaneus BMD was measured by densitometry.
The validity of the questionnaire was demonstrated, with Spearman correlation coefficients of 0.014 to 0.467. The Bland-Altman test also found no differences in study variables between the two methods. Correlation analysis showed that the BMD was significantly associated with the intake of vitamin D, vitamin A, vitamin B12, folate, thiamine and iron. Total fat consumption was not associated with BMD but the intake of monounsaturated fatty acids, EPA, DHA and cholesterol showed a significant correlation.
The questionnaire evaluates the consumption of energy and nutrients with adequate validity. Its application revealed the importance for bone health of a diet rich in B-group vitamins, vitamin D, calcium, iron, monounsaturated fatty acids and n-3.

Rivas A, Romero A, Mariscal M, Monteagudo C…
Nutr Hosp
PMID: 19893861 | Free Full Text | Full Text English Translation

The full text has a very interesting chart with a list of nutrients and their correlation with bone density.

Japanese Apricot Shows Potential to Prevent Osteoporosis

Abstract

A Prunus mume extract stimulated the proliferation and differentiation of osteoblastic MC3T3-E1 cells.

Osteoporosis is a serious disease caused by decreased bone mass. There is constant matrix remodeling in bones, by which bone formation is performed by osteoblastic cells, whereas bone resorption is accomplished by osteoclast cells. We investigated the effect of a Japanese apricot (Prunus mume SIBE. et ZUCC.) extract on the proliferation and osteoblastic differentiation in pre-osteoblastic MC3T3-E1 cells. An alkaline phosphatase (ALP) activity assay, cell proliferation assay, alizarin red staining and expression analysis of osteoblastic genes were carried out to assess the proliferation and osteoblastic differentiation. The water-soluble fraction of Prunus mume (PWF) increased the ALP activity, cell proliferation and mineralization. The gene expression of osteopontin and bone morphogenetic protein-2, which are markers in the early period of osteoblastic differentiation, were significantly enhanced by the PWF treatment. PWF therefore stimulated the proliferation and osteoblastic differentiation of cells and may have potential to prevent osteoporosis.

Kono R, Okuno Y, Inada K, Tokuda A…
Biosci. Biotechnol. Biochem. 2011
PMID: 21979066 | Free Full Text

B12 Decreases Fracture Risk

Abstract

Vitamin B12, folate, homocysteine, and bone health in adults and elderly people: a systematic review with meta-analyses.

Elevated homocysteine levels and low vitamin B12 and folate levels have been associated with deteriorated bone health. This systematic literature review with dose-response meta-analyses summarizes the available scientific evidence on associations of vitamin B12, folate, and homocysteine status with fractures and bone mineral density (BMD). Twenty-seven eligible cross-sectional (n = 14) and prospective (n = 13) observational studies and one RCT were identified. Meta-analysis on four prospective studies including 7475 people showed a modest decrease in fracture risk of 4% per 50 pmol/L increase in vitamin B12 levels, which was borderline significant (RR = 0.96, 95% CI = 0.92 to 1.00). Meta-analysis of eight studies including 11511 people showed an increased fracture risk of 4% per μ mol/L increase in homocysteine concentration (RR = 1.04, 95% CI = 1.02 to 1.07). We could not draw a conclusion regarding folate levels and fracture risk, as too few studies investigated this association. Meta-analyses regarding vitamin B12, folate and homocysteine levels, and BMD were possible in female populations only and showed no associations. Results from studies regarding BMD that could not be included in the meta-analyses were not univocal.

van Wijngaarden JP, Doets EL, Szczecińska A, Souverein OW…
J Nutr Metab 2013
PMID: 23509616 | Free Full Text

MMPs a Potential Target

Abstract

Hydrogen sulfide and sodium nitroprusside compete to activate/deactivate MMPs in bone tissue homogenates.

Bone microvascular remodeling is the primary predictor of bone structure and function. Remodeling by its very nature implies synthesis and degradation of the extracellular matrix. Normally, 50% of total protein in the vessel wall is elastin. During remodeling, elastin is degraded by specialized matrix metalloproteinases (MMPs). Because the turnover of elastin is 1000-fold slower than that of collagen, most of the elastin is replaced by stiffer collagen. Stiffer vessels impose pressure on the aortic valve, causing regurgitation and increased pulse pressure. On the other hand, high MMP activity will cause vascular dilatation, leading to aneurysm. Therefore, balanced constitutive remodeling is necessary for adequate bone structure and function. Interestingly, collagen-degrading MMPs are involved in various pathological conditions, including osteoporosis, osteoarthritis, and cardiovascular disease.

Sodium nitroprusside is a nitric oxide donor that could potentially alter MMP activity via vasodilation in vivo, but can also produce peroxynitrite, which activates MMPs by combining with superoxide. Moreover, hydrogen sulfide is a known antioxidant as well as a vasodilator, and is also speculated to contribute directly to MMP activity. We hypothesized that hydrogen sulfide reduced activity of MMP in ex vivo bone tissue homogenates and that sodium nitroprusside would increase MMP activity in vitro.
We surgically removed the tibia and femur from anesthetized mice, and prepared bone tissue homogenates using a mortar and pestle, measured the protein concentration with a spectrophotometer, and detected MMP activity using gelatin gel zymography.
Our data showed increased MMP activity at a sodium nitroprusside concentration of 1 μM, and MMP activity increased exponentially. There was a decrease in MMP activity with increasing hydrogen sulfide, beginning at 16 μM (P < 0.01) and continuing to 40 μM. Moreover, sodium nitroprusside 3 μM was able to overcome the decrease in MMP activity that occurred with hydrogen sulfide 40 μM; this resulted in a more pronounced exponential increase in MMP activity.
There are several substances that can potentially be used to decrease MMP activity and to alleviate pathological remodeling by MMPs.

Vacek TP, Qipshidze N, Tyagi SC
Vasc Health Risk Manag 2013
PMID: 23658491 | Free Full Text

Low B Vitamins May be Risk for Bone Loss

Abstract

Plasma B vitamins, homocysteine, and their relation with bone loss and hip fracture in elderly men and women.

Elevated homocysteine is a strong risk factor for osteoporotic fractures among elders, yet it may be a marker for low B-vitamin status.
Our objective was to examine the associations of plasma concentrations of folate, vitamin B12, vitamin B6, and homocysteine with bone loss and hip fracture risk in elderly men and women. This was a longitudinal follow-up study of the Framingham Osteoporosis Study.
Community dwelling residents of Framingham, MA, were included in the study.
A total of 1002 men and women (mean age 75 yr) was included in the study.
Baseline (1987-1989) blood samples were used to categorize participants into plasma B-vitamin (normal, low, deficient) and homocysteine (normal, high) groups. Femoral neck bone mineral density (BMD) measured at baseline and 4-yr follow-up was used to calculate annual percent BMD change. Incident hip fracture was assessed from baseline through 2003.
Multivariable-adjusted mean bone loss was inversely associated with vitamin B6 (P for trend 0.01). Vitamins B12 and B6 were inversely associated with hip fracture risk (all P for trend < 0.05), yet associations were somewhat attenuated and not significant after controlling for baseline BMD, serum vitamin D, and homocysteine. Participants with high homocysteine (>14 micromol/liter) had approximately 70% higher hip fracture risk after adjusting for folate and vitamin B6, but this association was attenuated after controlling for vitamin B12 (hazard ratio = 1.49; 95% confidence interval 0.91, 2.46).
Low B-vitamin concentration may be a risk factor for decreased bone health, yet does not fully explain the relation between elevated homocysteine and hip fracture. Thus, homocysteine is not merely a marker for low B-vitamin status.

McLean RR, Jacques PF, Selhub J, Fredman L…
J. Clin. Endocrinol. Metab. Jun 2008
PMID: 18364381 | Free Full Text

AKG Prevents Bone Loss in Dexamethasone-Treated Pigs

Abstract

Postnatal administration of 2-oxoglutaric acid improves articular and growth plate cartilages and bone tissue morphology in pigs prenatally treated with dexamethasone.

The potential effects of prenatal administration of dexamethasone (DEX) and postnatal treatment with 2-oxoglutaric acid (2-Ox) on postnatal development of connective tissue of farm animals were not examined experimentally. The aim of this study was to establish changes in morphological parameters of bone and articular and growth plate cartilages damaged by the prenatal action of DEX in piglets supplemented with 2-Ox. The 3 mg of DEX was administered by intramuscular route every second day from day 70 of pregnancy to parturition and then piglets were supplemented with 2-Ox during 35 days of postnatal life (0.4 g/kg body weight). The mechanical properties, BMD and BMC of bones, and histomorphometry of articular and growth plate cartilages were determined. Maternal treatment with DEX decreased the weight by 48%, BMD by 50% and BMC by 61% of the tibia in male piglets while such action of DEX in female piglets was not observed. DEX led to thinning of articular and growth plate cartilages and trabeculae thickness and reduced the serum GH concentration in male piglets. The administration of 2-Ox prevented the reduction of trabeculae thickness, the width of articular and growth plate cartilages in male piglets connected with higher growth hormone concentration compared with non-supplemented male piglets. The result showed that the presence of 2-Ox in the diet had a positive effect on the development of connective tissue in pigs during suckling and induced a complete recovery from bone and cartilage damage caused by prenatal DEX action.

Tomaszewska E, Dobrowolski P, Wydrych J
J. Physiol. Pharmacol. Oct 2012
PMID: 23211309 | Free Full Text