Renata Neves Granito

In vivo biological performance of a novel highly bioactive glass-ceramic (Biosilicate®): A biomechanical and histomorphometric study in rat tibial defects

This study aimed to investigate bone responses to a novel bioactive fully crystallized glass-ceramic of the quaternary system P(2)O(5)-Na(2)O-CaO-SiO(2) (Biosilicate®). Although a previous study demonstrated positive effects of Biosilicate® on in vitro bone-like matrix formation, its in vivo effect was not studied yet. Male Wistar rats (n = 40) with tibial defects were used. Four experimental groups were designed to compare this novel biomaterial with a gold standard bioactive material (Bioglass® 45S5), unfilled defects and intact controls. A three-point bending test was performed 20 days after the surgical procedure, as well as the histomorphometric analysis in two regions of interest: cortical bone and medullary canal where the particulate biomaterial was implanted. The biomechanical test revealed a significant increase in the maximum load at failure and stiffness in the Biosilicate® group (vs. control defects), whose values were similar to uninjured bones. There were no differences in the cortical bone parameters in groups with bone defects, but a great deal of woven bone was present surrounding Biosilicate® and Bioglass® 45S5 particulate. Although both bioactive materials supported significant higher bone formation; Biosilicate® was superior to Bioglass® 45S5 in some histomorphometric parameters (bone volume and number of osteoblasts). Regarding bone resorption, Biosilicate® group showed significant higher number of osteoclasts per unit of tissue area than defect and intact controls, despite of the non-significant difference in the osteoclastic surface as percentage of bone surface. This study reveals that the fully crystallized Biosilicate® has good bone-forming and bone-bonding properties.

Comparison of thoracic kyphosis degree, trunk muscle strength and joint position sense among healthy and osteoporotic elderly women: A cross-sectional preliminary study

Increased thoracic kyphosis is one of the most disfiguring consequences of osteoporotic spine fractures in the elderly. However, mechanisms involved in the increasing of the kyphosis degree among osteoporotic women are not completely understood. Then, the aims of this cross-sectional preliminary study were comparing thoracic kyphosis degree, trunk muscle peak torque and joint position sense among healthy and osteoporotic elderly women and investigating possible factors affecting the kyphosis degree. Twenty women were selected for 2 groups: healthy (n=10) and osteoporotic (n=10) elderly women. Bone mineral density (BMD), thoracic kyphosis degree, trunk muscles peak torque and joint position sense were measured. Differences among groups were analyzed by Students Test T for unpaired data. Correlations between variables were performed by Pearsons coefficient correlation. The level of significance used for all comparisons was 5% (p≤0.05). We observed that the osteoporotic women demonstrated a significantly higher degree of kyphosis and lower trunk extensor muscle peak torque. Moreover, it was found that the BMD had a negative correlation with the thoracic kyphosis degree. Kyphosis degree showed a negative correlation between extensor muscle strength and joint position sense index. This study suggests that lower BMD may be associated to higher degree of kyphosis degree, lower trunk extensors muscle strength and an impaired joint position sense. It is also suggested that lower extensor muscle strength may be a factor that contributes to the increasing in kyphosis thoracic degree.

Influence of a physical training program on muscle strength, balance and gait velocity among women with osteoporosis

Objectives: The trend towards increased life expectancy will certainly lead to increases in morbidity and mortality relating to osteoporosis. Because of the lack of well defined protocols on the intensity and frequency of easily performed physical exercises for Brazilian women, this study proposed to analyze the effects of a training program for ankle muscle strength, balance performance and gait velocity among women with a densitometric diagnosis of osteoporosis. Methods: Twelve female volunteers (age 68.7 ± 2.7 years) underwent physical evaluation and subsequent reevaluation after twelve weeks. The physical activity program was guided by a physical therapist, who conducted 60-minute sessions, three times a week for twelve weeks. Each training session included some stretching exercises, strengthening exercises for the ankle dorsiflexor and plantar-flexor muscles, with 50% of 10-repetition maximum (10-RM), and balance training. Results: The variables analyzed regarding balance index, gait velocity and muscle strength presented significant improvement (p ≤ 0.05), as shown by the Wilcoxon non-parametric test. Conclusion: After the 12-week exercise program, the participants presented benefits in terms of their fitness. The results demonstrate that the training had a role in improving the condition of this group of patients, thus suggesting that this program was effective, easy to implement and safe for Brazilian women with osteoporosis. Therefore, it can be seen that physical activity programs are efficient in improving balance performance, gait velocity and ankle muscle strength among elderly women with osteoporosis.

Biomechanical properties: effects of low-level laser therapy and Biosilicate® on tibial bone defects in osteopenic rats

Purpose The aim of this study was to investigate the effects of laser therapy and Biosilicate® on the biomechanical properties of bone callus in osteopenic rats. Methods Fifty female Wistar rats were equally divided into 5 groups (n=10/group): osteopenic rats with intact tibiae (SC); osteopenic rats with unfilled and untreated tibial bone defects (OC); osteopenic rats whose bone defects were treated with Biosilicate® (B); osteopenic rats whose bone defects were treated with 830-nm laser, at 120 J/cm2 (L120) and osteopenic rats whose bone defects were treated with Biosilicate® and 830-nm laser, at 120 J/cm2 (BL120). Ovariectomy (OVX) was used to induce osteopenia. A non-critical bone defect was created on the tibia of the osteopenic animals 8 weeks after OVX. In Biosilicate® groups, bone defects were completely filled with the biomaterial. For the laser therapy, an 830-nm laser, 120 J/cm2 was used. On day 14 postsurgery, rats were euthanized, and tibiae were removed for biomechanical analysis. Results Maximal load and energy absorption were higher in groups B and BL120, according to the indentation test. Animals submitted to low-level laser therapy (LLLT) did not show any significant biomechanical improvement, but the association between Biosilicate® and LLLT was shown to be efficient to enhance callus biomechanical properties. Conversely, no differences were found between study groups in the bending test. Conclusions Biosilicate® alone or in association with low level laser therapy improves biomechanical properties of tibial bone callus in osteopenic rats.

Redução da dor em mulheres com osteoporose submetidas a um programa de atividade física

Este estudo teve por objetivo avaliar a dor e o consumo de analgesicos em mulheres com osteoporose, apos a realizacao de um programa de atividade fisica. Participaram do estudo 15 mulheres com media de idade 59±7,6 anos, com diagnostico densitometrico em L2-L4 de osteoporose e que haviam feito uso de analgesicos para dorsalgia pelo menos tres vezes por semana no mes precedente a avaliacao inicial. A dor foi avaliada por questoes extraidas do Osteoporosis Assessment Questionnaire, aplicadas antes e apos um programa de atividade fisica; o escore variou de 0 (melhor, sem dor) a 10 (pior, dor diaria). O programa, que consistiu em caminhadas, exercicios livres de membros superiores e inferiores e relaxamento, foi realizado duas vezes por semana durante 28 semanas consecutivas. Os dados foram tratados estatisticamente. Comparando-se as pontuacoes obtidas, a dor apresentou uma diminuicao significativa entre a avaliacao inicial (7,33±3,05) e final (4,17±2,61, p=0,0007). Observou-se tambem uma reducao no consumo de analgesicos. Esses resultados sugerem que o programa de atividade fisica foi efetivo para a diminuicao da dor, contribuindo para a melhora da qualidade de vida das mulheres com osteoporose.

Calcium phosphate fibers coated with collagen: In vivo evaluation of the effects on bone repair.

The aim of this study was to assess the characteristics of the CaP/Col composites, in powder and fiber form, via scanning electron microscopy (SEM), pH and calcium release evaluation after immersion in SBF and to evaluate the performance of these materials on the bone repair process in a tibial bone defect model. For this, four different formulations (CaP powder - CaPp, CaP powder with collagen - CaPp/Col, CaP fibers - CaPf and CaP fibers with collagen - CaPf/Col) were developed. SEM images indicated that both material forms were successfully coated with collagen and that CaPp and CaPf presented HCA precursor crystals on their surface. Although presenting different forms, FTIR analysis indicated that CaPp and CaPf maintained the characteristic peaks for this class of material. Additionally, the calcium assay study demonstrated a higher Ca uptake for CaPp compared to CaPf for up to 5 days. Furthermore, pH measurements revealed that the collagen coating prevented the acidification of the medium, leading to higher pH values for CaPp/Col and CaPf/Col. The histological analysis showed that CaPf/Col demonstrated a higher amount of newly formed bone in the region of the defect and a reduced presence of material. In summary, the results indicated that the fibrous CaP enriched with the organic part (collagen) glassy scaffold presented good degradability and bone-forming properties and also supported Runx2 and RANKL expression. These results show that the present CaP/Col fibrous composite may be used as a bone graft for inducing bone repair.

Degree of thoracic kyphosis and peak torque of trunk flexors and extensors among healthy women

Objective The aim of this study was to analyze the effects of aging on the degree of thoracic kyphosis and peak torque of the trunk flexor and extensor muscles among women without a densitometric diagnosis of osteoporosis. Methods Thirty women were selected to make up three groups: young women (n = 10; 24.60 ± 2.27 years of age); adults (n = 10; 43.50 ± 2.88); and elderly women (n = 10; 62.40 ± 2.67). Bone mineral density (BMD), degree of thoracic kyphosis and peak torque of the trunk flexors and extensors were evaluated. Differences between the groups were evaluated using the Kruskal–Wallis ANOVA and Mann–Whitney U tests. Pearsons correlation coefficient was used to assess correlations between the variables. The significance level was taken to be 5% (p ≤ 0.05). Results The elderly group presented a greater degree of thoracic kyphosis (p = 0.009) and lower peak torque of the trunk flexors and extensors than the young group. The adult group presented lower peak torque of the trunk than the young group. A negative correlation was observed between age and peak torque of the trunk flexors and extensors (p ≤ 0.001), and a positive correlation between age and the degree of thoracic kyphosis (r = 0.58; p ≤ 0.001). The elderly group presented higher values for the eccentric/concentric ratio of the peak torque for flexors (p = 0.03) and extensors (p = 0.02). Conclusion This study suggests that physiological aging may be associated with a greater degree of thoracic kyphosis and lower muscle strength of the trunk flexors and extensors. Moreover, the elderly women showed a relative capacity for preservation of eccentric strength.