Vitamin D and estrogen receptor-alpha genotype and indices of bone mass and bone turnover in Danish girls

Investigation of the Relationship Between Fok1 and Col1A1 Gene Polymorphisms and Development of Treatment-Related Bone Complications in Children with Acute Lymphoblastic Leukemia

Objective:

In acute lymphoblastic leukemia (ALL), various clinical risk factors and genetic predispositions contribute to the development of bone complications during and after chemotherapy. In this study, we aimed to investigate whether vitamin D receptor (VDR) Fok1 and collagen protein Col1A1 Sp1-binding site gene polymorphisms, which are important in bone mineral and matrix formation, have effects on the development of bone abnormalities in childhood ALL survivors.

Materials and Methods:

Fifty children with ALL who were treated with the ALL Berlin-Frankfurt-Muenster-95 protocol between 1998 and 2008 and were followed for at least 7 years were enrolled. The control group consisted of 96 healthy children. VDR Fok1 and Col1A1 Sp1-binding site gene polymorphisms were analyzed by polymerase chain reaction and restriction fragment length polymorphism. Bone mineral density (BMD) and markers of bone metabolism were all noted. All patients who presented with pain in the joints were examined for bone pathologies while on chemotherapy or during long-term follow-up.

Results:

Low BMD (16%), osteoporosis (12%), and osteonecrosis (8%) were present in a total of 18 patients (36%). The frequency of osteonecrosis and total bone abnormalities was significantly higher in children aged ≥10 years (p=0.001). The risk of low BMD and osteonecrosis was higher in those with vitamin D deficiency. Only the Col1A1 Sp1-binding site gene polymorphism showed a significant association in ALL patients with osteonecrosis.

Conclusion:

The development of therapy-induced bone mineral loss and osteonecrosis in children with ALL is frequent and the risk is especially higher in children aged ≥10 years and with vitamin D deficiency. The association between Col1A1 Sp1-binding site gene polymorphisms and osteonecrosis has to be assessed in a larger group of ALL survivors.

Influence of Vitamin D Receptor Gene Fok1 Polymorphism on Bone Mass Accrual Post Calcium and Vitamin D Supplementation

OBJECTIVE

To examine the association of vitamin D receptor (VDR) gene polymorphisms of the Fok1 locus on bone mass accrual in Indian girls used to a low calcium intake.

METHODS

An intervention trial was undertaken in 102 girls aged 8-16 y, attending a state run school in Pune city, India. All girls received 500 mg calcium daily and 30,000 IU of vitamin D3 quarterly for one year. Dietary calcium intake was evaluated. Bone mineral content (BMC), bone area (BA) and bone mineral density (BMD) were measured at total body using Dual Energy X-ray Absorptiometry (Lunar DPX-PRO). Polymorphisms of the Fok1 locus of the vitamin D Receptor (VDR) gene were detected using SYBR Green quantitative polymerase chain reaction.

RESULTS

The prevalence of Fok1 polymorphism was 43.1% (Ff), 9.8% (ff) and 47.1% (FF). At baseline, FF genotype had significantly lower BMD as compared to ff and Ff genotype (p < 0.05). At baseline, majority of girls (82.4%) were hypocalcemic with low calcium intake. Post-supplementation, FF genotype had significantly lower bone mass as compared to ff and Ff genotype. Significant increase in BMC [Ff (17.9%); ff (18.1%); FF (17.4%)], and BMD [Ff (5.4 %); ff (6.3%); FF (4.8%)] was observed post supplementation (p value < 0.05), though percentage increase in BMC and BMD was similar for three Fok1 polymorphisms (p > 0.1).

CONCLUSIONS

VDR gene polymorphism, as defined by Fok1 genotype had no positive influence on bone mass accrual in response to calcium supplementation.

Association between vitamin D receptor gene polymorphisms (Fok1 and Bsm1) and osteoporosis: a systematic review

Osteoporosis is a health concern characterized by reduced bone mineral density (BMD) and increased risk of fragility fractures. Many studies have investigated the association between genetic variants and osteoporosis. Polymorphism and allelic variations in the vitamin D receptor gene (VDR) have been found to be associated with bone mineral density. However, many studies have not been able to find this association. Literature review was conducted in several databases, including MEDLINE/Pubmed, Scopus, EMBASE, Ebsco, Science Citation Index Expanded, Ovid, Google Scholar, Iran Medex, Magiran and Scientific Information Database (SID) for papers published between 2000 and 2013 describing the association between Fok1 and Bsm1 polymorphisms of the VDR gene and osteoporosis risk. The majority of the revealed papers were conducted on postmenopausal women. Also, more than 50% studies reported significant relation between Fok1, Bsm1 and osteoporosis. Larger and more rigorous analytical studies with consideration of gene-gene and gene-environment interactions are needed to further dissect the mechanisms by which VDR polymorphisms influence osteoporosis.

Hormonal and biochemical parameters correlated with bone densitometric markers in prepubertal Hungarian children

BACKGROUND

The conditions that define bone development in prepuberty profoundly influence bone health later in life. We aimed to reveal important determinants of bone mass in Tanner stage I.

METHODS

We studied 84 healthy children (43 girls and 41 boys) aged 7 to 11 years. Serum estradiol (E2), 25-hydroxyvitamin D3-vitamin [25(OH)D3], intact parathyroid hormone (PTHi), osteocalcin (OC) and β-crosslaps (CTXs) were longitudinally analyzed (Roche Diagnostics System). Total and spine bone mineral content (tBMC and LBMC) and density (tBMD and LBMD) were assessed, and total fat body mass index (FBMi) was calculated (DXA Lunar Prodigy).

RESULTS

The serum PTHi, OC and LBMD values were significantly higher in girls than in boys. The mean 25(OH)D3 level was lower but not significantly in girls compared to boys. Significant negative correlation was found between PTHi and 25(OH)D3 levels (r=-0.28; p=0.011) when tested in all subjects, but no correlation was detected when the gender groups were separately tested. There was a trend for higher E2 levels in girls. Significant positive correlation (r=0.32; p=0.042) was detected between FBMi and E2 concentration in girls only. A significant negative correlation was found between E2 and 25(OH)D3 levels (r=-0.37, p<0.05) in girls with elevated (>3.6pmol/l) PTHi and with suboptimal (<75nmol/l) 25(OH)D3 levels. Furthermore, positive correlations were noted between E2 and CTXs and OC (r=0.54, p<0.01 and r=0.39, p<0.03) and a marginally significant positive correlation (r=0.33; p=0.06) was detected between OC and PTHi levels in girls. However, we detected no correlations when these markers were analyzed in boys. There was a significant correlation between E2 and all BMC and LBMD values in both genders. The tBMD, LBMD and tBMC values showed weak, but significant negative associations with 25OHD3 levels (β=-0.44 to -0.55; p<0.001) in girls only. All BMD and BMC values were positively predicted by OC levels, but not by CTXs, in both genders. Among the biochemical markers, E2 was the only factor correlating with all dependent variables (BMCs and BMDs) in both genders. Among all parameters analyzed, FBMi (β=0.64) showed the strongest influence on tBMC characteristically in girls only.

CONCLUSIONS

Our results support that 1.) E2 levels play a key role in defining bone turnover and bone mass in both genders already in prepuberty; 2.) high PTHi levels in childhood should be evaluated with caution, because the normal range for serum PTHi in different Tanner stage groups is not well established; and 3.) the negative correlation between 25(OH)D and E2 and the positive correlation between PTHi and OC suggest that estrogens regulate PTHi indirectly and cause lower circulating 25(OH)D3 levels. We propose that the decreased levels of 25(OH)D3 reflect not the real vitamin supply, but may rather be the result of E2 regulation. Therefore, the actual serum 25OHD levels may underestimate the availability of factors supporting bone formation.

Selected risk factors of fractures in children — own observation

Bone fractures may depend on Vitamin D Receptor Gene (VDR), bone mineral density, bone turnover markers. Patients and methods. 161 patients were recruited and underwent: skeletal densitometry (DXA) method and bone turnover studies (Osteocalcin and Ntx).The study group was evaluated using restriction enzyme digestion at BsmI (rs1544410), FokI (rs2228570), ApaI (rs7975232) and TaqI (rs731236), polymorphic sites of the VDR gene. Multivariate logistic regression was used to assess factor significance. The model included variables with sex- and age-standardized parameters, VDR genotypes, and bone metabolism marker levels. Results. Factors associated with fractures were: osteocalcin concentration and Z-score BMDt. Odds Ratio (OR) values equaled: 1.01 (95%Confidence Interval (95%CI) 1.00–1.02) for osteocalcin (p=0.006), and 0.66 (95%CI 0.42-1.03; p=0.07) for Z-score BMDt. In patients with reduced bone mass, factors related to fractures were: osteocalcin (0.04) and carriage of BsmI b (0.07) or ApaI a alleles (0.08). ORs were 1.01 (95%CI 1.00–1.02) for OC, 0.29 (95%CI 0.07–1.14) for BsmI, and 2.13 (95%CI 0.91–4.99) for ApaI polymorphic allele carriage. Conclusions. Carriage of BsmI b allele reduces, while carriage of ApaI a allele and heightened osteoclacin level increase the risk of fractures in study children with reduced bone mass. VDR polymorphism, bone mineral density and bone formation’s marker — osteocalcin maybe considered as risk factor for fracure in children from Lodz region.

Known VDR polymorphisms are not associated with bone mineral density measures in pediatric Cushing disease

Decreased bone mineral density (BMD) has been documented in adults with Cushing disease (CD), and allelic variants of the vitamin D receptor (VDR) gene have been associated with osteopenia. Genetic factors play an important role in bone accrual and its response to various diseases; among them, the most studied are the allelic variants of the VDR gene. There is debate as to whether described variants in the VDR gene have an effect on BMD. In the current study, we sought to analyze whether BMD differences in patients with CD were associated with the Taq1 and Apal VDR allelotypes. The data showed lack of association between BMD and these widely studied VDR polymorphisms, suggesting that the effect of endogenous hypercortisolism on bone in the context of CD does not depend on VDR genotypes.

Vitamin D receptor gene polymorphism and bone mineral density in 0-6-year-old Han children

This study aims to investigate the four vitamin D receptor (VDR) gene single nucleotide polymorphisms and their possible relationship with bone mineral density (BMD) in Chinese 0-6-year-old Han children. Two hundred four 0-6-year-old Han children without metabolic bone disease were randomly recruited in Shanghai, China. The BMD of the middle tibia was measured by an ultrasonic bone density instrument. VDR genotypes were determined by polymerase chain reaction restriction fragment length polymorphism using endonuclease ApaI, BsmI, TaqI and FokI. The alleles of a, T, b and F and the genotypes of aa, TT, bb and Ff were predominant. The frequency alleles of a, T, b and F were, respectively, 70.6, 95.8, 95.3 and 57.6%. When the influences of confounders such as serum 25(OH)D, serum zinc and outdoor activities on BMD were removed, the genotypes of BsmI and FokI were found apparently to be related to BMD. The BMD of the Bb carrier was much lower than that of the bb carrier (22.00 ± 27.84 and 43.14 ± 31.98, P < 0.05). The BMD of the ff carrier was lower than that of the Ff or FF carrier (26.97 ± 34.22 and 37.95 ± 29.70 and 53.52 ± 30.35, P < 0.001), while the genotypes of ApaI and TaqI have no relation with BMD in 0-6-year-old Han children. These findings show that the Bb and ff genotypes of the VDR BsmI and FokI variants are significantly associated with a decreased BMD in Chinese Han children aged 0-6 years, while the VDR ApaI and TaqI polymorphisms are not significantly associated with it.

Does vitamin D supplementation of healthy Danish Caucasian girls affect bone turnover and bone mineralization?

INTRODUCTION

A high peak bone mass may be essential for reducing the risk of osteoporosis later in life and a sufficient vitamin D level during puberty may be necessary for optimal bone accretion and obtaining a high peak bone mass. Dietary intake and synthesis during winter of vitamin D might be limited but the effect of vitamin D supplementation in adolescence on bone mass is not well established.

OBJECTIVE

To investigate the effect of supplementation with 5 and 10 microg/day vitamin D(3) for 12 months in 11- to 12-year-old girls on bone mass and bone turnover as well as the possible influence of VDR and ER genotype on the effect of the supplementation.

METHODS

The girls (n=221) were randomized to receive either 5 microg or 10 microg vitamin D(3) supplementation per day or placebo for 12 months. Whole body and lumbar spine bone mass measured by DXA and pubertal status were determined at baseline and after 12 months whereas physical activity and dietary intake of calcium and vitamin D were assessed at baseline. Serum (S) 25-hydroxyvitamin D (25OHD), S-osteocalcin, S-parathyroid hormone, S-calcium, S-inorganic phosphate, urinary (U) pyridinoline (Pyr) and deoxpyridinoline (Dpyr) were measured at baseline and after 6 and 12 months.

RESULTS

The S-25OHD concentration increased (p<0.001) relative to the baseline values in the groups receiving either 5 microg/day (mean+/-SD; 11.0+/-10.3 nmol/l, baseline 41.9+/-17.6 nmol/l) or 10 microg/day (13.3+/-11.8 nmol/l, baseline 44.4+/-16.6 nmol/l) vitamin D(3) for 12 months compared to placebo (-3.1+/-9.8 nmol/l, baseline 43.4+/-17.1 nmol/l). There was no effect of vitamin D-supplementation on biomarkers for bone turnover or on whole body or spine bone mineral augmentation. However, vitamin D supplementation increased whole body bone mineral density (BMD) (p=0.007) and bone mineral content (BMC) (p=0.048) in the FF VDR genotype but not in the Ff or ff VDR genotypes.

CONCLUSION

Supplementation with vitamin D (5 or 10 microg/day) over 12 months increased the S-25OHD concentration but there was no effect on indices of bone health in the entire group of girls. However, there was an effect on BMD for a subgroup with the FF VDR genotype indicating an influence of genotype.

Vitamin D receptor gene polymorphisms modulate the skeletal response to vitamin D supplementation in healthy girls

OBJECTIVES

Vitamin D receptor (VDR) gene plays an important role in bone mass regulation. We have previously shown a beneficial effect of vitamin D supplementation on bone mass in girls. This study investigated whether the musculo-skeletal response to Vitamin D was modulated by polymorphisms in VDR gene.

DESIGN

Randomized placebo-controlled trial.

METHODS

179 girls (10-17 years), were randomly assigned to placebo or Vitamin D3 for one year. VDR genotypes were determined in 167 girls using BsmI, TaqI and ApaI restriction enzymes. Bone mass at the spine, hip, forearm and total body, and lean mass were measured by DXA at baseline and at one year.

RESULTS

After one year, VDR gene polymorphisms using Bsm1 and TaqI restriction enzymes were associated with percent changes in bone area, BMC and BMD at multiple skeletal sites in the Vitamin D3 group but not in the placebo group. The least increments were observed in the BB and tt genotypes. No similar effect was observed with ApaI enzyme. This relationship between VDR genotypes and changes in BMD and BMC remained significant after adjustment for puberty, changes in lean mass, height and bone area.

CONCLUSION

VDR gene polymorphisms influence the skeletal response to vitamin D supplementation in healthy adolescent girls.

The bone mass density in postmenopausal women using hormonal replacement therapy in relation to polymorphism in vitamin D receptor and estrogen receptor genes

The aims of the study were as follows: (1) To identify the differences in spinal body mass density (BMD) in relation to polymorphism in vitamin D receptor (VDR) and estrogen receptor-alpha (ERalpha) genes in untreated women with postmenopausal osteoporosis. (2) To assess the efficacy of treatment in women with postmenopausal osteoporosis in relation to polymorphism in VDR and ERalpha genes. (3) To find the estradiol concentration necessary to protect bone tissue in patients with a given polymorphism in VDR and ERalpha genes.

METHODS

The study included 44 postmenopausal women with primary osteoporosis who used cyclic hormonal replacement therapy (HRT) for a year. The polymorphism of ERalpha and VDR genes were evaluated. We also determined the age, body mass index and spinal BMD before and after 12 months of administration the HRT.

RESULTS

We found a significant spinal BMD increase, what is connected with ERalpha genotype and both VDR and ERalpha genes. There is no such a correlation observed in polymorphism of VDR gene.

CONCLUSIONS

(1) There is no relationship between VDR and ERalpha genes polymorphism and the stage of osteoporosis related to the spinal BMD value before treatment. (2) The XX, PP or Bb markers or only X, P, B alleles are connected with a significant decrease of treatment efficacy. (3) Estradiol serum concentration before and during HRT is not dependent on the polymorphism of VDR and ERalpha genes.

The role of estrogen receptor-alpha gene TA polymorphism and aromatase gene TTTA polymorphism on peak bone mass attainment in males: is there an additive negative effect of certain allele combinations?

Idiopathic osteoporosis in males is influenced predominantly by low peak bone mass as a feature under a strong genetic control. Among a number of candidate genes, alpha-estrogen receptor (ERalpha) and CYP19 genes are of particular interest due to important role of estrogen in pathophysiology of osteoporosis. In the present study we examined the association of certain allelic combinations of ERalpha gene thymine-adenine (TA) polymorphism and aromatase gene TTTA polymorphism on bone mineral density (BMD) in young men. The study sample consisted of 92 unrelated healthy male volunteers, aged 21-35. In each subject, lumbar spine and proximal femur BMD, parameters of bone turnover and 25-OHD level were measured. Two ERalpha (TA)( n ) alleles, allele 19 and allele 21, were found to be associated with lower BMD. The presence of allele 19 was associated with significantly lower lumbar spine (P = 0.006) and trochanter (P = 0.02) BMD while the subjects positive for allele 21 had significantly lower lumbar spine (P = 0.04), trochanter (P = 0.02) and total hip (P = 0.03) BMD. Men with CYP19 (TTTA)(7-3)/ERalpha (TA)(19) allele combination had significantly lower lumbar spine BMD (P = 0.02) and those with CYP19 (TTTA)(7-3)/ERalpha (TA)(21) allele combination had significantly lower BMD for all three measurements, i.e. lumbar spine (P = 0.02), femoral neck (P = 0.02) and total hip (P = 0.008). These particular combinations of high-risk alleles were associated with lower median lumbar spine, femoral neck and total hip BMD than either of the allele alone suggesting that negative effect of two risk alleles on peak bone mass add up.

Molecular genetic studies of gene identification for osteoporosis

This review comprehensively summarizes the most important and representative molecular genetics studies of gene identification for osteoporosis published up to the end of September 2007. It is intended to constitute a sequential update of our previously published reviews covering the available data up to the end of 2004. Evidence from candidate gene-association studies, genome-wide linkage and association studies, as well as functional genomic studies (including gene-expression microarray and proteomics) on osteogenesis and osteoporosis, are reviewed separately. Studies of transgenic and knockout mice models relevant to osteoporosis are summarized. The major results of all studies are tabulated for comparison and ease of reference. Comments are made on the most notable findings and representative studies for their potential influence and implications on our present understanding of genetics of osteoporosis. The format adopted by this review should be ideal for accommodating future new advances and studies.

Bone mass and breast milk calcium concentration are associated with vitamin D receptor gene polymorphisms in adolescent mothers

Lactation-associated bone loss has been reported in adolescent mothers. Polymorphisms in the vitamin D receptor (VDR) gene may contribute to differences in the physiologic skeletal response to lactation in these mothers. We evaluated the influence of VDR gene polymorphisms ApaI, BsmI, and TaqI on bone mass, bone and calcium-related hormones, and breast milk calcium of lactating adolescents with habitually low calcium intake. Total body bone mineral content (TBMC), total body bone mineral density (TBMD), lumbar spine BMD (LSBMD), serum hormones [intact parathyroid hormone (iPTH), 25-hydroxyvitamin D, insulin-like growth factor-I (IGF1), prolactin, and estradiol), and breast milk calcium were measured in 40 lactating Brazilian adolescents (15-18 y), and compared by VDR genotype subgroups after adjustment for calcium intake and postmenarcheal and lactational periods. TBMD and LSBMD Z scores were -0.55 +/- 1.01 and -1.15 +/- 1.48, respectively. LSBMD was higher (21%; P < 0.05) in adolescents with the aa genotype (n = 5) compared with those with the AA genotype (n = 7). TBMC and IGF1 were higher (23 and 50%, respectively; P < 0.05) in adolescents with tt (n = 4) than those with TT (n = 29) and Tt (n = 7) genotypes. Breast milk calcium and serum iPTH were higher (24 and 80%, respectively; P < 0.05) in adolescents with bb (n = 8) compared with those with BB (n = 21) genotype. These results indicate that bone mass and breast milk calcium are significantly associated with VDR genotypes in lactating Brazilian adolescents. Those with aa and tt genotypes had a better bone status and those with bb genotype had greater breast milk calcium.

Genotypes and clinical aspects associated with bone mineral density in Argentine postmenopausal women

The aim of this study was to determine genotypes and clinical aspects associated with bone mineral density (BMD) in postmenopausal women from Córdoba, Argentina. Polymorphisms were assessed by RFLP-PCR technique using BsmI and FokI for vitamin D receptor gene (VDR) and XbaI and PvuII for estrogen receptor-alpha gene (ERalpha) as restrictases. Sixty-eight healthy, 54 osteopenic, and 64 osteoporotic postmenopausal women were recruited. Femoral neck and lumbar spine BMD were inversely correlated with age in the entire analyzed population. Height was lower in osteopenic and osteoporotic women as compared to healthy women (P < 0.05). Weight and body mass index (BMI) were the lowest in osteoporotic women (P < 0.01 versus healthy group). Serum procollagen type I Nterminal propeptide (PINP) was higher in osteoporotic women as compared to the other groups. Distribution of VDR and ERalpha genotypes was similar in the three groups. Genotype bb (VDR) was associated with low values of lumbar BMD in the healthy group (P < 0.05 versus genotype Bb), and with low values of femoral BMD (P < 0.05 versus genotype BB) in osteoporotic women. BB*Pp interaction was associated with the highest femoral neck BMD (P < 0.05), whereas the bb*xx interaction was associated with the lowest femoral neck BMD in the total population analyzed (P < 0.05). In conclusion, parameters such as age, height, weight, BMI, serum PINP, VDR genotypes, and interactions between VDR and ERalpha genotypes could be useful to predict a decrease in BMD in Argentine postmenopausal women.

Association analysis of the polymorphisms of the VDR gene with bone mineral density and the occurrence of fractures

Associations of the FokI, BsmI, ApaI, and TaqI polymorphisms of the vitamin D receptor (VDR) gene with the bone mineral density (BMD) of the lumbar part of the spinal column (BMD LS) and the neck of the femur (BMD FN), and with the occurrence of fractures, were studied using the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis on DNA isolated from peripheral blood of 239 women and 40 men from the region of western Poland. Three polymorphisms of the 3' end of the VDR gene (BsmI, ApaI, TaqI) indicated a strong linkage disequilibrium. Association analysis of the VDR gene FokI polymorphism with BMD LS showed a dose effect of allele f. The association of the bAT haplotype of the BsmI, ApaI, and TaqI polymorphisms of the VDR gene with BMD FN was statistically significant. The association of the ApaI polymorphism with the occurrence of fractures was observed. Associations were also observed between the occurrence of fractures and the baT haplotypes of the VDR gene.