Evaluation of the anti-osteoporotic effect of Ginkgo biloba L. in Wistar rats with glucocorticoid-induced-osteoporosis by bone densitometry using dual-energy x-ray absorptiometry (DEXA) and mechanical testing.

Evaluate the effect of the extract of Ginkgo biloba in the bone alkaline phosphatase, bone mineral density, in the mechanical properties of the tibia in rats with glucocorticoid-induced-osteoporosis. After osteoporosis induction, the rats were divided into five groups: Osteoporosis; EGb1 (28 mg/Kg); EGb2 (56 mg/Kg); alendronate (0.2 mg/animal) and control. The animals were treated during 20 and 30 days. The control group was compared with the osteoporosis's (Student's t-test), while the other were analyzed by ANOVA test followed by Tukey/Dunnett'T3 (p<0.05). In the osteoporosis group the bone alkaline phosphatase, bone mineral density, the bone stiffness, the maximum load and the resilience were reduced. The bone alkaline phosphatase values increased in the EGb1 and EGb2 groups (30 days). In addition, in the EGb2 and alendronate groups (20 and 30 days) the bone mineral density increased. The extract of Ginkgo biloba restored bone alkaline phosphatase and bone mineral density using dual-energy x-ray absorptiometry.

MTHFR C677T, MTHFR A1298C, and OPG A163G polymorphisms in Mexican patients with rheumatoid arthritis and osteoporosis.

MTHFR polymorphisms C677T and A1298C are associated with reduced MTHFR enzyme activity and hyperhomocysteinemia, which has been associated with osteoporosis. The A163G polymorphism in osteoprotegerin (OPG) has been studied in osteoporosis with controversial results. The objective of the present study was to investigate the association(s) among MTHFR C677T, MTHFR A1298C, and OPG A163G polymorphisms in Mexican patients with rheumatoid arthritis and osteoporosis. The femoral neck and lumbar spine bone mineral densities (BMDs) were measured in 71 RA patients, and genotyping for the three polymorphisms was performed via restriction fragment length polymorphism analysis. Patients with osteoporosis/osteopenia exhibited statistically significant differences in the genotype frequencies of MTHFR C677T as well as an association with femoral neck BMD; TT homozygotes had lower BMDs than patients with the CT genotype, and both of these groups had lower BMDs than patients with the CC genotype. The associations of the MTHFR C677T polymorphism with osteoporosis/osteopenia and femoral neck BMD suggest that these polymorphisms confer a risk of developing osteoporosis in patients with rheumatoid arthritis, a risk that may be reduced with folate and B complex supplementation.

Biosilicate® and low-level laser therapy improve bone repair in osteoporotic rats.

The aim of this study was to investigate the effects of a novel bioactive material (Biosilicate®) and low-level laser therapy (LLLT) on bone fracture consolidation in osteoporotic rats. Forty female Wistar rats were submitted to ovariectomy (OVX) to induce osteopenia. Eight weeks after surgery, the animals were randomly divided into four groups of 10 animals each: a bone defect control group (CG); a bone defect filled with Biosilicate group (BG); a bone defect filled with Biosilicate and irradiated with LLLT at 60 J/cm(2) group (BG60); and a bone defect filled with Biosilicate and irradiated with LLLT at 120 J/cm(2) group (BG120). Bone defects were surgically performed on both tibias. The size of particle used for Biosilicate was 180-212 µm. Histopathological analysis showed that bone defects were predominantly filled with the biomaterial in specimens treated with Biosilicate. LLLT with either 60 or 120 J/cm(2) was able to increase collagen, Cbfa-1, VGEF and COX-2 expression in the circumjacent cells of the biomaterial. A morphometric analysis revealed that the Biosilicate + laser groups showed a higher amount of newly formed bone. Our results indicate that laser therapy improves bone repair process in contact with Biosilicate as a result of increasing bone formation, as well as COX-2 and Cbfa-1 immunoexpression, angiogenesis and collagen deposition in osteoporotic rats.

Oxidative stress as a risk factor for osteoporosis in elderly Mexicans as characterized by antioxidant enzymes.

BACKGROUND: Oxidative stress (OxS) has recently been linked with osteoporosis; however, we do not know the influence of OxS as an independent risk factor for this disease. METHODS: We conducted a case-control study in 94 subjects > or =60 years of age, 50 healthy and 44 with osteoporosis. We measured total antioxidant status, plasma lipid peroxides, antioxidant activity of superoxide dismutase and glutathione peroxidase (GPx), and calculated the SOD/GPx ratio. Bone mineral density was obtained at the peripheral DXA in calcaneus using a portable Norland Apollo Densitometer. Osteoporosis was considered when subjects had a BMD of 2.5 standard deviations or more below the mean value for young adults. RESULTS: GPx antioxidant activity was significantly lower in the group of subjects with osteoporosis in comparison with the group of healthy subjects (p < 0.01); in addition, the SOD/GPx ratio was significantly higher in the group of individuals with osteoporosis (p < 0.05). In logistic regression analysis, we found OxS to be an independent risk factor for osteoporosis (odds ratio [OR] = 2.79; 95% confidence interval [95% CI] = 1.08-7.23; p = 0.034). CONCLUSION: Our findings suggest that OxS is an independent risk factor for osteoporosis linked to increase of SOD/GPx ratio.

Abnormal osteogenesis in osteoporotic patients is reflected by altered mesenchymal stem cells dynamics.

Bone marrow contains a population of mesenchymal stem cells with the ability to differentiate into cells that form bone, cartilage, adipose, and other connective tissues. Stem cells can be isolated from bone marrow aspirates and expanded in vitro. Presently, most stem cells studies have been performed in cells obtained from "healthy" control subjects. The goal of this study was to compare the functional characteristics of mesenchymal stem cells derived from "healthy" control and osteoporotic postmenopausal women to better understand the mechanisms involved in the pathogenesis of this disease. Osteoporotic and control stem cells have similar morphology and size and express similar cell surface antigens as evidenced by their reactivity with cell specific monoclonal antibodies. Mesenchymal stem cells from osteoporotic women differ from controls in having a lower growth rate than control cells, being refractory to the mitogenic effect of IGF-1, and exhibiting a deficient ability to differentiate into the osteogenic linage as evidenced by the alkaline phosphatase activity and calcium phosphate deposition. We conclude that in osteoporosis stem cell growth, proliferative response and osteogenic differentiation are significantly affected. Also, the study of mesenchymal stem cells from osteoporotic postmenopausal women may provide a better understanding of the mechanisms involved in the pathogenesis of the osteoporosis. It may also serve to test in vitro in rapid manner novel new therapeutic strategies.

Fosfatasa alcalina:valoración sérica en bioquímica clínica

Efectos de la edad y sexo en la proporción de fosfatasa alcalina en la sangre. Métodos de análisis. Preparación del paciente y recolección de la muestra. Constancia de la actividad

Fosfatasa alcalina:valoración sérica en bioquímica clínica

Efectos de la edad y sexo en la proporción de fosfatasa alcalina en la sangre. Métodos de análisis. Preparación del paciente y recolección de la muestra. Constancia de la actividad