Association of Bone Marrow Sphingosine 1-phosphate Levels with Osteoporotic Hip Fractures

BACKGROUND: Sphingosine 1-phosphate (S1P) has been discovered to be a critical regulator of bone metabolism. Very recently, we found that higher circulating S1P levels were associated with higher rate of prevalent osteoporotic fracture in human. METHODS: This was a cross-sectional study of 16 patients who underwent hip replacement surgeries. Bone marrow fluids were obtained during hip surgeries, and the S1P levels were measured using a competitive enzyme-linked immunosorbent assay (ELISA) assay. Bone mineral densities (BMDs) at various skeletal sites were obtained using dual energy X-ray absorptiometry. RESULTS: Among 16 patients, 4 patients were undergone operations due to hip fractures, and the others were done by any other causes. Bone marrow S1P levels were significantly lower in patients with hip fractures than in those without, before and after adjusting for confounding factors (P=0.047 and 0.025, respectively). We failed to demonstrate significant associations between bone marrow S1P levels and any BMD values (gamma=0.026-0.482, P=0.171-0.944). CONCLUSIONS: In conjunction with our previous findings, these suggest that the effects of gradient between peripheral blood and bone marrow, but not S1P itself, may be the most critical on bone metabolism.

Cholestasis Causes Discrepancy in HDL-Cholesterol Levels Measured Using Various Methods

Herein, we report a case in which cholestasis caused discrepancy in high-density lipoprotein (HDL)-cholesterol levels measured using various methods. The discrepancy in HDL-cholesterol level originated from the abnormal increase in the level of an unusual lipoprotein, apo E-rich HDL, in the patient's serum. An abnormal slow alpha-migrating lipoprotein was observed on agarose gel electrophoresis, and an abnormal large-sized HDL was observed in a lipoprotein subfraction study. The level of apolipoprotein E was elevated.

Cholestasis Causes Discrepancy in HDL-Cholesterol Levels Measured Using Various Methods

Herein, we report a case in which cholestasis caused discrepancy in high-density lipoprotein (HDL)-cholesterol levels measured using various methods. The discrepancy in HDL-cholesterol level originated from the abnormal increase in the level of an unusual lipoprotein, apo E-rich HDL, in the patient's serum. An abnormal slow alpha-migrating lipoprotein was observed on agarose gel electrophoresis, and an abnormal large-sized HDL was observed in a lipoprotein subfraction study. The level of apolipoprotein E was elevated.

Response: The Effects of Combination Therapy of Cathepsin K Inhibitor and PTH on Change in Bone Mineral Density in an Animal Model of Osteoporosis

No abstract available.

Response: The Effects of Combination Therapy of Cathepsin K Inhibitor and PTH on Change in Bone Mineral Density in an Animal Model of Osteoporosis

No abstract available.

Association of ADIPOR1 polymorphisms with bone mineral density in postmenopausal Korean women

Adiponectin may affect bone through interactions with two known receptors, adiponectin receptors (ADIPOR) 1 and 2. We examined the association between polymorphisms of ADIPOR1 and ADIPOR2 and bone mineral density (BMD) in postmenopausal Korean women. Six polymorphisms in ADIPOR1 and four polymorphisms in ADIPOR2 were selected and genotyped in all study participants (n = 1,329). BMD at the lumbar spine and femur neck were measured using dual-energy X-ray absorptiometry. Lateral thoracolumbar (T4-L4) radiographs were obtained for vertebral fracture assessment and the occurrence of non-vertebral fractures examined using self-reported data. P values were adjusted for multiple testing using Bonferroni correction (Pcorr). ADIPOR1 rs16850799 and rs34010966 polymorphisms were significantly associated with femur neck BMD (Pcorr = 0.036 in the dominant model; Pcorr = 0.024 and Pcorr = 0.006 in the additive and dominant models, respectively). Subjects with the rare allele of each polymorphism had lower BMD, and association of rs34010966 with BMD showed a gene dosage effect. However, ADIPOR2 single nucleotide polymorphisms and haplotypes were not associated with BMD at any site. Our results suggest that ADIPOR1 polymorphisms present a useful genetic marker for BMD in postmenopausal Korean women.

Association of Paraoxonase 1 (PON1) polymorphisms with osteoporotic fracture risk in postmenopausal Korean women

There is increasing evidence of a biochemical link between lipid oxidation and bone metabolism. Paraoxonase 1 (PON1) prevents the oxidation of low-density lipoprotein (LDL) and metabolizes biologically active phospholipids in oxidized LDLs. Here, we performed association analyses of genetic variation in PON1 to ascertain its contribution to osteoporotic fractures (OFs) and bone mineral density (BMD). We directly sequenced the PON1 gene in 24 Korean individuals and identified 26 sequence variants. A large population of Korean postmenopausal women (n = 1,329) was then genotyped for eight selected PON1 polymorphisms. BMD at the lumbar spine and femoral neck was measured using dual-energy X-ray absorptiometry. Lateral thoracolumbar (T4-L4) radiographs were obtained for vertebral fracture assessment, and the occurrence of non-vertebral fractures (i.e., wrist, hip, forearm, humerus, rib, and pelvis) was examined using self-reported data. Multivariate analyses showed that none of the polymorphisms was associated with BMD at either site. However, +5989A>G and +26080T>C polymorphisms were significantly associated with non-vertebral and vertebral fractures, respectively, after adjustment for covariates. Specifically, the minor allele of +5989A>G exerted a highly protective effect against non-vertebral fractures (OR = 0.59, P = 0.036), whereas the minor allele of +26080T>C was associated with increased susceptibility to vertebral fractures (OR = 1.73, P = 0.020). When the risk for any OFs (i.e., vertebral or non-vertebral) was considered, the statistical significance of both polymorphisms persisted (P = 0.002-0.010). These results suggest that PON1 polymorphisms could be one of useful genetic markers for OF risk in postmenopausal women.

The Effects of Combination Therapy of Cathepsin K Inhibitor and PTH on Change in Bone Mineral Density in an Animal Model of Osteoporosis

BACKGROUND: We hypothesized that combination therapy of cathepsin K inhibitor (CTKi) and human parathyroid hormone (1-34) (teriparatide, PTH) would overcome the coupling phenomenon of bone resorption and formation and thus may rapidly increase bone mass. METHODS: We selected a dose of zoledronic acid (ZA) that had shown similar effects with CTKi on body bone mineral density (BMD) change during the preliminary experiment. Female mice were subjected to ovariectomized (OVX control) or a sham operation (SHAM group). The mice were treated with CTKi (CTKi group), ZA (ZA group), PTH (PTH group) or with a combination of PTH with ZA (ZA + PTH group) or CTKi (CTKi + PTH group) for 8 weeks. Total BMD was measured before the operation and at 4 and 8 weeks. RESULTS: In the preliminary results, 10 microg/kg of ZA showed similar BMD changes with CTKi. Compared with the OVX control, BMD in the SHAM, ZA, CTKi, PTH, ZA + PTH, and CTKi + PTH groups was significantly increased after treatment. BMD in the CTKi + PTH group, but not in the ZA + PTH group increased more significantly than in the PTH group at the end of treatment. Compared with the OVX control, changes in BMD in the SHAM, ZA, CTKi, PTH, ZA + PTH, and CTKi + PTH groups increased significantly after 8 weeks of treatment. The change in BMD in the CTKi + PTH group, but not in the ZA + PTH group was more significantly increased than the change in BMD in the PTH group. CONCLUSION: When combined with PTH, CTKi augmented the anabolic action of PTH. Therefore, combination therapy with CTKi and PTH might be a new therapeutic modality capable of overcoming the coupling phenomenon, thereby markedly and rapidly increasing bone mass.

Genome-wide Association Study Identification of a New Genetic Locus with Susceptibility to Osteoporotic Fracture in the Korean Population

Osteoporotic fracture (OF), along with bone mineral density (BMD), is an important diagnostic parameter and a clinical predictive risk factor in the assessment of osteoporosis in the elderly population. However, a genomewide association study (GWAS) on OF has not yet been clarified sufficiently. To identify OF-associated genetic variants and candidate genes, we conducted a GWAS in a population-based cohort (Korean Association Resource [KARE], n=1,427 [case: 288 and control: 1139]) and performed a de novo replication study in hospital-based individuals (Asan and Catholic Medical Center [ACMC], n=1,082 [case: 272 and control: 810]). In a combined meta-analysis, a newly identified genetic locus in an intergenic region at 10p11.2 (near genes FZD8 and ANKRD30A ) showed the most significant association (odd ratio [OR] = 2.00, 95% confidence interval [CI] = 1.47~2.74, p=1.27x10(-5)) in the same direction. We provide the first evidence for a common genetic variant influencing OF and genetic information for further investigation in bone metabolism.

Association of Common Vitamin D Receptor Gene Variations with Fracture Risk and Bone Mineral Density in Postmenopausal Korean Population

Osteoporosis is characterized by impaired osteogenesis. BMD is a major determinant of bone strength. The role of the VDR gene in predisposition to primary osteoporosis has been recognized. However, population-based case-control studies have been reported controversial results for known candidate genes in an ethnically distinct group. To determine the genetic effects of VDR variants on osteoporosis and BMD, we directly sequenced the VDR gene in 24 unrelated Korean individuals and identified eighteen sequence variants. We investigated the potential involvement of eight SNPs in osteoporosis in postmenopausal women (n = 729). Two SNPs (LD) in intron 2, -5294G > C (rs2238135) and -4817G > A (rs17882443) showed the evidence of association with enhanced BMD of the femoral neck (p(additive) =0.031 for rs2238135; p(additive)=0.017 and p(dominant)= 0.019 for 17882443). Moreover, VDR -4817G > A was significantly associated with protective effect on all fracture risk (p(recessive)=0.035, OR=0.2, 95% CI=0.05~0.89), and tended to be higher BMD values at various proximal femur sites. Therefore, we suggest that the -4817G > A may be useful genetic marker for vitamin D-related metabolism and may have an important role in the increased BMD of the proximal femur in postmenopausal Korean women.

A Case of Hyperthyroidism Associated with Symptomatic Hypercalcemia / 대한내분비학회지

Two of the common causes of hypercalcemia are malignancy and primary hyperparathyroidism. These disorders are easily diagnosed by the clinical manifestations and measurement of the serum intact parathyroid hormone (PTH) level. On the other hand, hyperthyroidism is an uncommon cause of hypercalcemia. The diagnosis of hypercalcemia associated with hyperthyroidism can only be made by excluding the common causes of hypercalcemia and by observing the improvement of the hypercalcemia and its associated symptoms with normalizing the thyroid function. Herein we reported our experience with a 67 year-old woman who presented with nausea and vomiting. She showed elevated serum calcium and phosphorus levels. Serum intact PTH level was 1.1 pg/mL (normal range; 10~65). The results of the thyroid function test were compatible with hyperthyroidism. After resolution of the thyrotoxicosis with combination treatment of methimazol and Lugol's solution, the patient's serum calcium and phosphorus levels were normalized and the symptoms were improved.

Methionine synthase reductase polymorphisms are associated with serum osteocalcin levels in postmenopausal women

Homocysteine (Hcy) is thought to play an important role in the development of osteoporosis and fracture. Methionine synthase reductase (MTRR) is an enzyme involved in the conversion of Hcy to methionine. We hypothesized that certain genetic polymorphisms of MTRR leading to reduced enzyme activity may cause hyperhomocysteinemia and affect bone metabolism. We therefore examined the associations of the A66G and C524T polymorphisms of the MTRR gene with bone mineral density (BMD) and serum osteocalcin levels in postmenopausal women. Although we did not detect any significant associations between MTRR polymorphisms and BMD or serum osteocalcin levels, we found that the 66G/524C haplotype, which has reduced enzyme activity, was significantly associated with serum osteocalcin levels in a gene-dose dependent manner (P=0.002). That is, the highest osteocalcin levels (34.5+/-16.8 ng/ml) were observed in subjects bearing two copies, intermediate osteocalcin levels (32.6+/-14.4 ng/ml) were observed in subjects bearing one copy, and the lowest levels of osteocalcin (28.8+/-10.9 ng/ml) were observed in subjects bearing no copies. These results suggest that the 66G/524C haplotype of the MTRR gene affect bone turn over rate.

Effects of alpha-Lipoic Acid on Bone Metabolism in Rats with Low Bone Mass / 대한내분비학회지

BACKGROUND: Growing evidence has shown a biochemical link between increased oxidative stress and reduced bone density. In our previous study, alpha-lipoic acid (alpha-LA), a thiol antioxidant, suppressed both osteoclastogenesis and bone resorption, and also prevented TNF-alpha-induced apoptosis of osteoblast lineages. The effects of alpha-LA were investigated on bone metabolism in rats with a low bone mass. METHODS: An ovariectomy (OVX) or Talc injection (inflammation-mediated osteopenia, IMO) was performed in 12 week old female Sprague-Dawley rats. Diets containing either 0.3%, 0.5% or 1.0% alpha-LA were administered to the OVX rats for 16 weeks, and to the IMO rats for 21 days. The bone mineral densities (BMD) of the anterior-posterior lumbar spine and total femur were measured using dual-energy X-ray absorptiometry (Hologic QDR 4500-A), with small animal software. The plasma bone specific alkaline phosphatase activity (BSAP) and urinary free deoxypyridinoline concentration (DPD) were determined using enzyme immunoassay methods. RESULTS: The body weights were significantly decreased in the OVX rats on the diets containing 0.3 and 0.5% alpha-LA than in the OVX control. No significant differences in the BMD at either site were noted between rats administered the diets with or without alpha-LA. However, the administration of various doses of alpha-LA noticeably decreased the level of urinary DPD in both the OVX and IMO rats. High doses of alpha-LA (0.5% and/or 1.0%) also decreased the levels of plasma BSAP in both models. CONCLUSION: Although no increase in BMD was demonstrated by the administration of alpha-LA, these results suggest that alpha-LA suppresses the rates of bone turnover in rats with a low bone mass

Prescriptions and indications of hormone replacement therapy / 대한내과학회지

No abstract available.

Association between Bone Mineral Density and LDL Receptor-Related Protein 5 Gene Polymorphisms in Young Korean Men

Recently, It has been reported that the LDL receptor-related protein 5 (LRP5) regulates bone formation, and that mutations of the gene cause osteoporosis-pseudoglioma syndrome or high bone mass phenotypes. However, the mutations cannot explain a genetic trait for osteoporosis in the general population because of their rarity. From 219 Korean men aged 20-34 yr, we looked for six known polymorphisms causing amino acid changes in the LRP5 coding region, and investigated their association with bone mineral density (BMD) at the following anatomical sites: lumbar spine (L2-L4) and the left proximal femur (femoral neck, Ward's triangle, trochanter and shaft). We found that the Q89R polymorphism was significantly associated with BMD at the femoral neck and Ward's triangle (p=0.004 and <0.001, respectively). However, after adjusting for age, weight and height, a statistically significant association only occurred at the Ward's triangle (p=0.043), and a marginal association was observed at the femoral neck (p=0.098). No A400V, V667M, R1036Q and A1525V polymorphisms were found, and no statistically significant association was found between the A1330V polymorphism and BMD at any sites. Although we failed to demonstrate a clear association between the LRP5 polymorphism and peak bone mass in young men, the present study suggests that larger-scale studies on the Q89R polymorphism need to be performed.

Analysis of Bone Mineral Density and Biochemical Markers in Hip Fractures Injured by Low-energy Trauma / 대한정형외과학회잡지

PURPOSE: This study was conducted to compare bone mineral density (BMD) and biochemical markers of bone metabolism of an osteoporotic hip fracture group with those of a control group. MATERIALS AND METHODS: The fracture group included 76 patients with hip fractures who were injured by low energy trauma from November, 1999 to August, 2003. The control group consisted of 83 patients recruited over the same period. There were 22 men and 54 women in the fracture group, with an average age of 67.2 years for men and 71.1 years for women. In the control group, there were 22 men and 61 women, of average age 67.9 years for men and 70.1 years for women. There were no siginificant differences in age, height, weight, or body mass index. We analyzed BMD by a dual energy X-ray absorptiometry (DEXA). Bone specific alkaline phosphatase (B-ALP) and osteocalcin were used as markers of bone formation and urine-deoxypyridinoline (DPD) as a maker of bone resorption. RESULTS: B-ALP showed a significant decrease in the fracture group (p<0.05). Also, average serum osteocalcin showed a significant decrease in the fracture group (p<0.05). There was no significant difference in urine-DPD between the two groups. The mean values of BMD in men and women were significantly decreased in the fracture group. CONCLUSION: The results of this study suggest that a decreased BMD contributes to hip fractures in elderly people and that B-ALP and serum osteocalcin rather than urine-DPD are reliable biochemical markers of bone metabolism in osteoporotic hip fractures.

Serum Leptin Levels in Relation to Quantitative Ultrasound Values of Calcaneus in Korean Postmenopausal Women in Chung-Up District / 대한내분비학회지

BACKGROUND: Obese postmenopausal women usually have a tend to have greater bone mineral density than lean women. This has been attributed to either the mechanical effects of their excessive weight on bone tissue or to their high body fat content. A recent study demonstrated that leptin, the hormone produced in adipocytes, acts on bone metabolism. These findings have prompted speculations on the possible role of leptin in the protective effect of obesity on bone. METHEODS: We studied the relationship between serum leptin levels and quantitative ultrasound (QUS) values of calcaneus in 94 postmenopausal Korean women who were randomly selected from the population of the Chung-Up osteoporosis prevalence study. QUS values, broadband ultrasound attenuation and speed of sound; were measured at the calcaneus. RESULTS: Leptin values were strongly correlated with body mass index (r = 0.478, p< 0.001), confirming a positive relationship between leptin levels and fat mass. In contrast, no significant correlations were observed between serum leptin levels and calcaneal QUS values. CONCLUSION: Our results suggest that circulating plasma leptin does not have a significant influence on QUS values of calcaneus in Korean postmenopausal women.

Effects of Glucocorticoid on Apoptosis of Human Bone Marrow Osteogenic Stromal Cells / 대한내분비학회지

BACKGROUND: Osteoporosis is one of the most serious side effects of long-term glucocorticoid therapy, but the mechanism of glucocorticoid-induced bone loss remains poorly defined. Glucocorticoid induces decreased bone formation and death of isolated segments of bone (osteonecrosis) suggesting that glucocorticoid excess may affect the birth or death rate of bone cells and thereby reduce their numbers. It has been known that reduction in bone formation is due to reduced proliferation in osteoblast precursor cells and reduced matrix synthesis in mature osteoblast. Here, we present evidence for dexamethasone-induced apoptosis on human bone marrow stromal cells (hBMSC). To understand the mechanism of glucocorticoid-induced osteoporosis, we investigated the effects of glucocorticoid on primary cultured hBMSC. METHEODS: Treatment with dexamethasone at the concentration of 10-9 M for 3~5 days significantly decreased cleavage tetrazolium salt WST-1 level/concentration by mitochondrial dehydrogenase in viable cells. Greater decrease was observed with higher concentration of dexamethasone (10-7 M, and 10-5 M). Apoptosis was measured by annexin V binding/propidium iodide using fluorescence-activated cell sorter (FACS) analysis and nuclear morphology stained with the fluorescence dye, Hoechst 33342. RESULTS: The level/concentration of apoptotic hBMSC (annexin V positive / PI negative) was increased with 10-9 M dexamethasone (1.2% to 5.3%) and further increased with 10-7 M, and 10-5 M concentration (11.7% and 12.5%, respectively). The same result was observed with Hoechst 33342 staining. CONCLUSION: These results indicate that glucocorticoid induces apoptosis on osteoblast precursor cell, hBMSC, and may contribute to decrease bone formation

Lack of Relationship between Vitamin D Receptor Polymorphism and Bone Erosion in Rheumatoid Arthritis

We performed this study to investigate the possible association between vitamin D receptor (VDR) gene polymorphism and the focal bone erosion in rheumatoid arthritis (RA) patients in Korea. One hundred and fifty-seven RA patients were enrolled and two control groups were selected. The focal bone erosion score was assessed by modified Sharp's method. Genotyping of VDR polymorphisms was performed by polymerase chain reaction and restriction fragment length polymorphism analysis using two restriction enzyme Taq I and Bsm I. Notably, the distribution of VDR genotype in Korean population was different from Caucasians. The frequencies of "tt" and "BB" genotypes were very rare both in RA patients and in control groups. The frequency distribution of the Taq I and Bsm I genotype was not different between RA patients (TT, 93.6%; Tt, 6.4%; tt, 0%; BB, 0.6%; Bb, 5.1%; bb, 94.3%) and control groups (TT, 90.8%; Tt, 7.5%; tt, 1.7%; BB, 1.4%; Bb, 8.1%; bb, 90.5%). There was no significant difference in the focal bone erosion score (mean+/-SD) according to the VDR genotypes of RA patients (TT, 0.92+/-1.79; Tt, 0.4+/-0.79; Bb, 0.43+/-0.80; bb, 0.92+/-1.79; p>0.05). In conclusion, these results suggest that VDR gene polymorphisms are not associated with the focal bone erosion in RA patients in Korea.

Association Between Peak Bone Mass and Genetic Polymorphisms of the Vitamin D Receptor, Estrogen Receptor, and Type I Collagen 1 Genes in Healthy Young Korean Women / 대한내분비학회지

BACKGROUND: Genetic suggest that strongest effect is observed in the premenopausal peak bone mass, which become less with age. However, the evaluation of candidate genes polymorphisms has been most frequently done in postmenopausal women and the results have been controversial. Therefore, we studied the possible association of the peak bone mass and candidate for osteoporosis genes polymorphism in premenopausal women. METHODS: The associations between BMD and polymorphisms of the vitamin D receptor (3'-end region by BsmI restriction enzyme and start codon by FokI restriction enzyme), estrogen receptor (by PvuII and XbaI restriction enzyme), and type I collagen 1 (Sp1 binding site by MscI and BalI restriction enzyme) genes were examined in 100 healthy young Korean women who had a peak bone mass (age 20-35 years). Bone mineral densities were measured by dual energy X-ray absorptiometry (DEXA). Dietary calcium intake was also measured using a food frequency questionnaire. RESULTS: The frequencies of the B allele of the vitamin D receptor gene BsmI polymorphism and the X allele in the estrogen receptor gene, XbaI polymorphisms were lower in Koreans than those in Caucasians. The allelic frequencies of the vitamin vitamin D receptor gene FokI polymorphism and the estrogen receptor gene PvuII polymorphism were similar to those of Caucasians. No significant association was found between BMD and the vitamin D receptor genotype according to BsmI or FokI polymorphisms. There was also no significant relation between the PvuII or XbaI polymorphisms of the estrogen receptor gene and BMD. The associations between BMD and cross-genotypes combining the vitamin D receptor gene (BsmI and FokI) and estrogen receptor gene (PvuII and XbaI) polymorphisms were also analyzed. Among the subjects who lacked the Bf haplotype of the vitamin D receptor gene, the BMD of the femoral neck area was significantly higher in subjects lacking Px haplotypes of the estrogen receptor gene than in those having Px haplotype (p < 0.05). When dietary calcium intake was taken into consideration, there were significant differences in BMD according to the cross-genotype in the group having a low calcium intake (< 500 mg/day). The subjects that lacked the Bf and Px haplotypes had a significantly higher BMD in the femoral neck (p < 0.01), Ward's triangle (p < 0.05), and in the trochanteric area (p < 0.05) than those who lacked Bf but a Px haplotype. We did not find a polymorphism in the Sp1 binding site of the type I collagen 1 gene in our subjects. CONCLUSION: These data suggest that a complex interaction of vitamin D and the estrogen receptor gene with the dietary calcium intake, rather than a polymorphism of a single gene, may influence peak bone mass in healthy young Korean women.