Bone morphogenetic proteins (BMPs) expression in the femoral heads of patients with avascular necrosis

Avascular necrosis (AVN) is a disorder of the bone repair process which usually results in femoral head (FH) destruction. Bone morphogenetic proteins (BMPs) are the key proteins regulating bone remodelling and healing. BMPs gene expression levels were analyzed in the normal and necrotic sites of osteonecrotic FHs. Quantitative RT-PCR for BMP-2, -4, -6, -7 genes was performed in bone tissue samples from 47 osteonecrotic FHs. Protein levels of BMP-2, -4, -6 were estimated by Western Blot. Statistical analysis was performed using the Wilcoxon signed rank test. BMP-2 and BMP-6 mRNA levels were higher in the normal than the necrotic site (normal/necrotic: 16.8/6.8 and 1.75/1.64, respectively). On the contrary, BMP-4 mRNA levels were higher in the necrotic (0.75) than the normal (0.62), while BMP-7 mRNA levels were extremely low. At the protein level, BMP-2 continued to have a higher expression in the normal region (normal/necrotic: 0.67/0.64). BMP-4 and -6 were detected at higher levels in the necrotic site (normal/necrotic: 0.51/0.61 for BMP-4, 0.51/0.56 for BMP-6), while BMP-7 was not detectable. Different BMP levels between the normal and necrotic site, as well as discrepancies between the gene and protein expression pattern suggest a different regulation mechanism for BMPs between the two regions of FHs. The understanding of the expression pattern and the correlation of BMPs could lead to a more successful use in the prevention and treatment of AVN. © 2013 Springer Science+Business Media Dordrecht

Expression profile of osteoprotegerin, RANK and RANKL genes in the femoral head of patients with avascular necrosis

Introduction: Femoral head avascular necrosis (AVN) is a recalcitrant disease of the hip that leads to joint destruction. Osteoprotegerin (OPG), Receptor Activator of Nuclear Factor kappa-B (RANK) and RANK ligand (RANKL) regulate the balance between osteoclasts-osteoblasts. The expression of these genes affects the maturation and function of osteoblasts-osteoclasts and bone remodeling. In this study, we investigated the molecular pathways leading to AVN by studying the expression profile of OPG, RANK and RANKL genes. Material and methods: Quantitative Real Time-PCR was performed for evaluation of OPG, RANK and RANKL expression. Analysis was based on parallel evaluation of mRNA and protein levels in normal/necrotic sites of 42 osteonecrotic femoral heads (FHs). OPG and RANKL protein levels were estimated by western blotting. Results: The OPG mRNA levels were higher (insignificantly) in the necrotic than the normal site (p. >. 0.05). Although the expression of RANK and RANKL was significantly lower than OPG in both sites, RANK and RANKL mRNA levels were higher in the necrotic part than the normal (p. <. 0.05). Protein levels of OPG and RANKL showed no remarkable divergence. Conclusions: Our results indicate that differential expression mechanisms for OPG, RANK and RANKL that could play an important role in the progress of bone remodeling in the necrotic area, disturbing bone homeostasis. This finding may have an effect on the resulting bone destruction and the subsequent collapse of the hip joint. © 2013

Novel Sequence Variations in the CER1 Gene Are Strongly Associated with Low Bone Mineral Density and Risk of Osteoporotic Fracture in Postmenopausal Women

Osteoporosis is a common skeletal disease characterized by a combination of low bone mass and increased fragility. In this case-control study, we investigated the possible association of two novel candidate genes, CER1 and TOB1, with bone mineral density (BMD) and fragility risk in 300 postmenopausal women of Hellenic origin. The entire CER1 and TOB1 gene sequences were amplified and resequenced to assess whether there is a correlation between these genes and BMD. We identified 26 variants in both genes. Statistical analysis did not reveal any correlation between TOB1 and osteoporosis. However, CER1 genetic analysis indicated that five polymorphisms, c.194C > G, c.507+506G > T, c.508-182A > G, c.531A > G, and c.*121T > C, were correlated, with a mean T score a parts per thousand currency signaEuro"2.2. In particular, the greater number of vertebral fractures was found in patients with osteoporosis carrying the G allele of c.531A > G SNP (p = 0.015). When multiple logistic regression analysis was performed, only the c.507+506G > T polymorphism was independently associated with hip fractures or the presence of any fracture (OR = 6.95, p = 0.016, and OR = 5.33, p < 0.001, respectively). These results suggest that CER1 gene variations play a significant role in determining BMD and vertebral or hip fractures, which might be helpful in clinical practice to identify patients with increased fracture risk

Expression profile of osteoprotegerin, RANK and RANKL genes in the femoral head of patients with avascular necrosis

Introduction: Femoral head avascular necrosis (AVN) is a recalcitrant disease of the hip that leads to joint destruction. Osteoprotegerin (OPG), Receptor Activator of Nuclear Factor kappa-B (RANK) and RANK ligand (RANKL) regulate the balance between osteoclasts-osteoblasts. The expression of these genes affects the maturation and function of osteoblasts-osteoclasts and bone remodeling. In this study, we investigated the molecular pathways leading to AVN by studying the expression profile of OPG, RANK and RANKL genes. Material and methods: Quantitative Real Time-PCR was performed for evaluation of OPG, RANK and RANKL expression. Analysis was based on parallel evaluation of mRNA and protein levels in normal/necrotic sites of 42 osteonecrotic femoral heads (FHs). OPG and RANKL protein levels were estimated by western blotting. Results: The OPG mRNA levels were higher (insignificantly) in the necrotic than the normal site (p > 0.05). Although the expression of RANK and RANKL was significantly lower than OPG in both sites, RANK and RANKL mRNA levels were higher in the necrotic part than the normal (p < 0.05). Protein levels of OPG and RANKL showed no remarkable divergence. Conclusions: Our results indicate that differential expression mechanisms for OPG, RANK and RANKL that could play an important role in the progress of bone remodeling in the necrotic area, disturbing bone homeostasis. This finding may have an effect on the resulting bone destruction and the subsequent collapse of the hip joint. (C) 2013 Published by Elsevier Inc

The 5′ regulatory region of the human fetal globin genes is a gene conversion hotspot

The human fetal globin genes consist of the first mammalian genomic loci for which gene conversion was reported. To date, 14 gene conversions have been described in the human Gγ- and Aγ-globin genes, the vast majority of which are restricted to the coding sequences. Here, we provide evidence for three new gene conversion events in the 5′ regulatory region of the human fetal globin genes, identified during a large genetic screening effort in adult individuals with high fetal hemoglobin (Hb) levels. The sequence variations, resulting from these conversion events, are transcriptionally silent polymorphisms that do not contribute to increased fetal Hb levels. Our results suggest that the 5′ regulatory region of the human fetal globin genes is a gene conversion hotspot that prevent globin gene promoter sequence diversification, further underlining the need for two functional fetal globin genes in fetal erythropoiesis. Copyright © Informa Healthcare USA, Inc

Predictive role of cytokine gene polymorphisms for the development of femoral head osteonecrosis

Introduction: Osteonecrosis (ON) is a multifactorial disease that leads to hip destruction. Lately, much focus has been at femoral head preservation with nonsurgical methods. In this study we examined the polymorphisms of IL-1α, IL-1R, IL-1RA, IL-4Rα, IL-1β, IL-12, γIFN, TGF-β, TNF-a, IL-2, IL-4, IL-6 and IL-10 genes for evaluation of their contribution in ON. Material and methods: DNA was extracted from 112 ON patients and 438 healthy donors. Analysis of the polymorphisms was completed using the PCR-SSP method. Statistical analysis was performed using the χ ^{2} test to compare the genotype and allelic frequency distribution. Results: The CT and GA genotypes of the IL-1α (-889) and TNF-a (-238) genes were found higher in the patients (51.8% and 10.8%, respectively) compared to the healthy donors (39.7% and 2.1%, respectively). In TGF-β codon 25, the G to C polymorphism in the homozygous state was found in 1.8% of the patients and the C allele frequency was 8.9%, whereas the G allele frequency was 91.1%. Also, at the IL-10 (-1082) gene the GG genotype was 16.2% in the controls whereas in the patients was 7.2%. Conclusions: Based on the above, we showed that certain genotypes of the IL-1α, TGF-β, IL-10 and TNF-a genes could be related in the pathogenesis of a complicated disease, such as osteonecrosis. The presence of one of the above mentioned polymorphisms or the simultaneous carriage of more than one may further increase the risk for osteonecrosis, especially in those at high risk, such as patients receiving corticosteroids. © 2012-IOS Press and the authors. All rights reserved

CER1 gene variations associated with bone mineral density, bone markers, and early menopause in postmenopausal women

Background: Osteoporosis has a multifactorial pathogenesis characterized by a combination of low bone mass and increased fragility. In our study, we focused on the effects of polymorphisms in CER1 and DKK1 genes, recently reported as important susceptibility genes for osteoporosis, on bone mineral density (BMD) and bone markers in osteoporotic women. Our objective was to evaluate the effect of CER1 and DKK1 variations in 607 postmenopausal women. The entire DKK1 gene sequence and five selected CER1 SNPs were amplified and resequenced to assess whether there is a correlation between these genes and BMD, early menopause, and bone turnover markers in osteoporotic patients. Results: Osteoporotic women seem to suffer menopause 2 years earlier than the control group. The entire DKK1 gene sequence analysis revealed six variations. There was no correlation between the six DKK1 variations and osteoporosis, in contrast to the five common CER1 variations that were significantly associated with BMD. Additionally, osteoporotic patients with rs3747532 and rs7022304 CER1 variations had significantly higher serum levels of parathyroid hormone and calcitonin and lower serum levels of osteocalcin and IGF-1. Conclusions: No significant association between the studied DKK1 variations and osteoporosis was found, while CER1 variations seem to play a significant role in the determination of osteoporosis and a potential predictive role, combined with bone markers, in postmenopausal osteoporotic women. © 2013 Koromila et al

Novel sequence variations in the CER1 gene are strongly associated with low bone mineral density and risk of osteoporotic fracture in postmenopausal women

Osteoporosis is a common skeletal disease characterized by a combination of low bone mass and increased fragility. In this case-control study, we investigated the possible association of two novel candidate genes, CER1 and TOB1, with bone mineral density (BMD) and fragility risk in 300 postmenopausal women of Hellenic origin. The entire CER1 and TOB1 gene sequences were amplified and resequenced to assess whether there is a correlation between these genes and BMD. We identified 26 variants in both genes. Statistical analysis did not reveal any correlation between TOB1 and osteoporosis. However, CER1 genetic analysis indicated that five polymorphisms, c.194C&gt;G, c.507+506G&gt;T, c.508-182A&gt;G, c.531A&gt;G, and c.*121T&gt;C, were correlated, with a mean T score ≤-2.2. In particular, the greater number of vertebral fractures was found in patients with osteoporosis carrying the G allele of c.531A&gt;G SNP (p = 0.015). When multiple logistic regression analysis was performed, only the c.507+506G&gt;T polymorphism was independently associated with hip fractures or the presence of any fracture (OR = 6.95, p = 0.016, and OR = 5.33, p &lt; 0.001, respectively). These results suggest that CER1 gene variations play a significant role in determining BMD and vertebral or hip fractures, which might be helpful in clinical practice to identify patients with increased fracture risk. © 2012 Springer Science+Business Media, LLC