| 1. |
- Brändström, Helena, et al.
(författare)
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Single nucleotide polymorphisms in the human gene for osteoprotegerin are not related to bone mineral density or fracture in elderly women
- 2004
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Ingår i: Calcified Tissue International. - : Springer Science and Business Media LLC. - 0171-967X .- 1432-0827. ; 74:1, s. 18-24
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Tidskriftsartikel (refereegranskat)abstract
- Osteoprotegerin (OPG), a secreted member of the tumor necrosis factor receptor family, is a potent inhibitor of osteoclast activation and differentiation. In animal models OPG prevents bone loss, and in humans bone resorption can be reduced by injections of OPG. OPG may also play a role in cardiovascular disease since mice lacking the OPG gene display arterial calcification. In a screening effort of the OPG gene, we recently discovered a single nucleotide polymorphism in the promoter region of OPG (T950C), and reported an association with vascular morphology and function in 59 healthy individuals. Due to the pronounced effect of OPG on bone turnover, the present study was conducted to investigate whether OPG polymorphisms are also associated with bone mineral density or with fracture. The relationship between single nucleotide polymorphisms in the promoter region of OPG (T950C) and the first intron (C1217T), and bone mineral density, measured by DXA in the hip or spine or ultrasound of the heel, was investigated in the Malmö OPRA-study of 1044 women, all 75 years old. The possible relation to fracture incidence was also analyzed. Among the 858 and 864 individuals respectively, genotyped, no significant associations between the investigated single nucleotide polymorphisms and bone mineral density measurements (T950C P = 0.50-0.64, C1217T P = 0.51-1.00), quantitative ultrasound measurements of the calcaneus, or fractures (T950C P = 0.61-0.66, C1217T P = 0.14-0.33) were found. Thus, our results show that polymorphisms in the OPG gene, one of which has previously been found to be associated with cardiovascular morphology and function, are not associated with bone mineral density in elderly Swedish women.
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| 2. |
- Gerdhem, Paul, et al.
(författare)
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Association of the collagen type 1 (COL1A 1) Sp1 binding site polymorphism to femoral neck bone mineral density and wrist fracture in 1044 elderly Swedish women
- 2004
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Ingår i: Calcified Tissue International. - : Springer Science and Business Media LLC. - 0171-967X .- 1432-0827. ; 74:3, s. 264-269
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Tidskriftsartikel (refereegranskat)abstract
- Identification of risk factors for osteoporosis has been essential for understanding the development of osteoporosis and related fragility fractures. A polymorphism of the binding site for the transcription factor Sp1 of the collagen I alpha 1 gene (COLIA1) has shown an association to bone mass and fracture, but the findings have not been consistent, which may be related to population differences. The Sp1 polymorphism was determined in 1044 women, all 75 years old, participating in the population-based Osteoporosis Prospective Risk Assessment study in Malmö (OPRA). Bone mineral density, heel ultrasound and all previous fractures were registered. BMD was 2.7% lower in the femoral neck in women carrying at least one copy of the "s" allele ( P = 0.027). There was no difference in bone mass at any other site, weight, BMI or age at menopause. Women with a prevalent wrist fracture (n = 181) had an increased presence of the "s" allele. The odds ratio for prevalent wrist fracture was 2.73 (95% CI 1.1-6.8) for the ss homozygotes and 1.4 (95% CI 1.0-2.0) for the Ss heterozygotes when compared with the SS homozygotes. In conclusion, in this large and homogeneous cohort of 75-year-old Swedish women, there was an association among the Sp1 COLIA1 polymorphism, bone mass, and fracture. The presence of at least one copy of the "s" allele was associated with lower femoral neck BMD and previous wrist fracture and in addition, it was related to an increased risk for wrist fracture.
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| 5. |
- Grundberg, Elin, et al.
(författare)
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Genetic variation in the human vitamin D receptor is associated with muscle strength, fat mass and body weight in Swedish women
- 2004
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Ingår i: European Journal of Endocrinology. - : Oxford University Press (OUP). - 0804-4643 .- 1479-683X. ; 150:3, s. 323-328
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Bone mineral density (BMD) is under strong genetic control and a number of candidategenes have been associated with BMD. Both muscle strength and body weight are considered to beimportant predictors of BMD but far less is known about the genes affecting muscle strength andfat mass. The purpose of this study was to investigate the poly adenosine (A) repeat and the BsmISNP in the vitamin D receptor (VDR) in relation to muscle strength and body composition in healthywomen. Design: A population-based study of 175 healthy women aged 20–39 years was used. Methods: The polymorphic regions in the VDR gene (the poly A repeat and the BsmI SNP) were amplifiedby PCR. Body mass measurements (fat mass, lean mass, body weight and body mass index) andmuscle strength (quadriceps, hamstring and grip strength) were evaluated. Results: Individuals with shorter poly A repeat, ss and/or absence of the linked BsmI restriction site(BB) have higher hamstring strength (ss vs LL, P ¼ 0.02), body weight (ss vs LL, P ¼ 0.049) andfat mass (ss vs LL, P ¼ 0.04) compared with women with a longer poly A repeat (LL) and/or thepresence of the linked BsmI restriction site (bb). Conclusions: Genetic variation in the VDR is correlated with muscle strength, fat mass and bodyweight in premenopausal women. Further functional studies on the poly A microsatellite areneeded to elucidate whether this is the functionally relevant locus or if the polymorphism is in linkagedisequilibrium with a functional variant in a closely situated gene further downstream of the VDR30UTR.
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| 6. |
- Larsson, Tobias Erik Martin, 1976-
(författare)
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The Role of Fibroblast Growth Factor 23 in Phosphate Homeostasis
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The regulation of serum phosphate (Pi) concentrations is a complex process and our current models are far from complete. Due to major advancements in biotechnology and the development of more powerful research tools, recent advances in the field of genetics has led to the identification of several candidates for the long sought-after phosphatonin(s), or Pi regulating hormones. One of these candidates is fibroblast growth factor 23 (FGF-23) and this thesis is based upon studies of the role of FGF-23 in Pi homeostasis. We demonstrate that FGF-23 is a secreted protein which is highly expressed in tumors giving rise to oncogenic hypophosphatemic osteomalacia (OOM). Furthermore, we have developed a two-site enzyme-linked immunosorbent assay for the detection of circulating FGF-23 and established that FGF-23 is present in the circulation of healthy individuals. Also, FGF-23 serum levels are elevated in patients with disturbances in Pi homeostasis such as OOM, X-linked hypophosphatemic rickets (XLH) and chronic kidney disease and are likely to play an important role in the pathogenesis of these disorders. A transgenic mouse model that express human FGF-23 under the control of the α1(I) collagen promoter exhibit similar clinical and biochemical characteristics as do patients with OOM, XLH and autosomal dominant hypophosphatemic rickets indicating that FGF-23 is an important determinant of Pi homeostasis, vitamin D metabolism and bone mineralization.
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| 7. |
- Larsson, Tobias, 1974, et al.
(författare)
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Transgenic mice expressing fibroblast growth factor 23 under the control of the alpha1(I) collagen promoter exhibit growth retardation, osteomalacia, and disturbed phosphate homeostasis.
- 2004
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Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 145:7, s. 3087-94
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Tidskriftsartikel (refereegranskat)abstract
- Mutations in the fibroblast growth factor 23 gene, FGF23, cause autosomal dominant hypophosphatemic rickets (ADHR). The gene product, FGF-23, is produced by tumors from patients with oncogenic osteomalacia (OOM), circulates at increased levels in most patients with X-linked hypophosphatemia (XLH) and is phosphaturic when injected into rats or mice, suggesting involvement in the regulation of phosphate (Pi) homeostasis. To better define the precise role of FGF-23 in maintaining Pi balance and bone mineralization, we generated transgenic mice that express wild-type human FGF-23, under the control of the alpha1(I) collagen promoter, in cells of the osteoblastic lineage. At 8 wk of age, transgenic mice were smaller (body weight = 17.5 +/- 0.57 vs. 24.3 +/- 0.37 g), exhibited decreased serum Pi concentrations (1.91 +/- 0.27 vs. 2.75 +/- 0.22 mmol/liter) and increased urinary Pi excretion when compared with wild-type littermates. The serum concentrations of human FGF-23 (undetectable in wild-type mice) was markedly elevated in transgenic mice (>7800 reference units/ml). Serum PTH levels were increased in transgenic mice (231 +/- 62 vs. 139 +/- 44 pg/ml), whereas differences in calcium and 1,25-dihydroxyvitamin D were not apparent. Expression of Npt2a, the major renal Na(+)/Pi cotransporter, as well as Npt1 and Npt2c mRNAs, was significantly decreased in the kidneys of transgenic mice. Histology of tibiae displayed a disorganized and widened growth plate and peripheral quantitative computerized tomography analysis revealed reduced bone mineral density in transgenic mice. The data indicate that FGF-23 induces phenotypic changes in mice resembling those of patients with ADHR, OOM, and XLH and that FGF-23 is an important determinant of Pi homeostasis and bone mineralization.
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| 9. |
- Omarsdottir, Sif, et al.
(författare)
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Increased rate of bone loss at the femoral neck in patients with chronic liver disease
- 2002
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Ingår i: European Journal of Gastroenterology and Hepathology. - 0954-691X .- 1473-5687. ; 14:1, s. 43-8
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE : Patients with chronic liver disease (CLD) have an increased prevalence of osteoporosis. The aim of this study was to evaluate prospectively the rate of bone loss and potential predictors of increased bone loss in a cohort of patients with CLD. DESIGN : Bone mineral density (BMD) was measured at baseline and at follow-up by dual-energy X-ray absorptiometry at the lumbar spine and the femoral neck. RESULTS : Forty-three patients (31 female, 12 male) were available for a second measurement of BMD, with a median of 25 months (range 18-41) between the measurements. Mean annual bone loss at the lumbar spine and the femoral neck, respectively, was 0.6 +/- 2.0% and 1.5 +/- 2.4% in females and 0.8 +/- 1.9% and 2.9 +/- 2.0% in males. The BMD Z score decreased significantly over time at the femoral neck (P = 0.005 and P = 0.02 for females and males, respectively). Bone loss was increased significantly at the lumbar spine in patients classified as Child-Pugh B + C compared with those classified as Child-Pugh A (P = 0.04). Serum levels of bilirubin correlated independently and positively, and 25-hydroxy vitamin D3 levels negatively, with bone loss at the femoral neck. CONCLUSIONS : Patients with CLD have increased bone loss at the femoral neck. Advanced liver disease is associated with increased bone loss, and hyperbilirubinaemia and low levels of vitamin D3 are predictors of increased bone loss.
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| 10. |
- Ribom, Eva L., et al.
(författare)
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Six months of hormone replacement therapy does not influence muscle strength in postmenopausal women
- 2002
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Ingår i: Maturitas. - 0378-5122 .- 1873-4111. ; 42:3, s. 225-31
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Postmenopausal hormone replacement therapy (HRT) has positive effects on fracture incidence before any effects on bone mineral density can be demonstrated. This has been attributed to increased muscle strength by HRT. This study was designed to evaluate the effect of 6 months of HRT on muscle strength in postmenopausal women. METHODS: Forty postmenopausal women, aged 60-78 were included in the study. They were randomly divided in two groups with 20 women in each group. One group received Menorest 50 microg/24 h (estradiol 4.3 mg) and Gestapuran 2.5 mg (medroxyprogesteron) daily and the other group received placebo treatment. The study was conducted as a double blinded, prospective and placebo controlled trial. Hand grip strength, isokinetic knee flexion and extention, and physical activity were measured before treatment, after 3 and 6 months. Physical activity was estimated using a classification system of physical activity. A JAMAR hydraulic hand dynamometer and a Cybex II dynamometer were used to evaluate muscle strength. RESULTS: Hand grip strength in the right hand, increased significantly in both groups (HRT P<0.001 and placebo P<0.01) and in the left hand in the HRT group (P<0.01). However, there were no differences in muscle strength between the two groups. There was no significant change in isokinetic knee flexion or extension after 6 months in either of the groups. The estimated physical activity increased slightly in the placebo group, but there was no significant difference compared to the treatment group. CONCLUSIONS: Our data suggest that 6 months of HRT does not influence muscle strength in postmenopausal women.
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