Influence of the geometry of nanostructured hydroxyapatite and alginate composites in the initial phase of bone repair

Abstract Purpose: To analyze, histomorphologically, the influence of the geometry of nanostructured hydroxyapatite and alginate (HAn/Alg) composites in the initial phase of the bone repair. Methods: Fifteen rats were distributed to three groups: MiHA - bone defect filled with HAn/Alg microspheres; GrHA - bone defect filled with HAn/Alg granules; and DV - empty bone defect; evaluated after 15 days postoperatively. The experimental surgical model was the critical bone defect, ≅8.5 mm, in rat calvaria. After euthanasia the specimens were embedded in paraffin and stained with hematoxylin and eosin, picrosirius and Masson-Goldner's trichrome. Results: The histomorphologic analysis showed, in the MiHA, deposition of osteoid matrix within some microspheres and circumjacent to the others, near the bone edges. In GrHA, the deposition of this matrix was scarce inside and adjacent to the granules. In these two groups, chronic granulomatous inflammation was noted, more evident in GrHA. In the DV, it was observed bone neoformation restricted to the bone edges and formation of connective tissue with reduced thickness in relation to the bone edges, throughout the defect. Conclusion: The geometry of the biomaterials was determinant in the tissue response, since the microspheres showed more favorable to the bone regeneration in relation to the granules.

Suplementação Nutricional de Cálcio eVitamina D para a Saúde Óssea e Prevençãode Fraturas Osteoporóticas / Nutritional Supplementation of Calcium and Vitamin D for Bone Health and Prevention of Osteoporotic Fractures

Objetivo: Contextualizar e descrever os principais efeitosda suplementação nutricional de cálcio (Ca) e vitamina D nasaúde óssea e prevenção de fraturas osteoporóticas.Material e método: O presente artigo foi elaborado atravésde consultas às bases de dados eletrônicas ScienceDirect,SciELO, PUBMED/MEDLINE, LILACS, Portal de Periódicosda CAPES e Google Acadêmico, considerando-se os artigos,nacionais e internacionais, publicados no período entre 2005e 2014. Para isto, utilizou-se os DeCS (Descritores deCiências da Saúde) da BIREME: Osteoporose, fraturasosteoporóticas, cálcio, vitamina D, suplementação nutricional.Resultados: Após levantamento bibliográfico, considerandoseos critérios de inclusão e exclusão, foram utilizados 30artigos. Os estudos têm utilizado valores médios desuplementação nutricional entre 200 a 1200mg/d (Miligramaspor dia) de Ca e 200 a 800UI/d (Unidades Internacionais pordia) de vitamina D em combinação, que variaram a dependerda influência de fatores preponderantes, tais como sexo,idade e níveis hormonais dos indivíduos avaliados. Conclusão:Tendo em vista que a suplementação de Ca e/ou vitamina Dcontribui para redução da perda de densidade mineral óssea(DMO) e, consequentemente, o risco de incidência de fraturasósseas osteoporóticas, otimizar o consumo dessesmicronutrientes essenciais para a manutenção da saúdeóssea, como Ca e vitamina D, torna-se uma alternativapromissora na redução dos danos causados pela senilidade...

Objective: To contextualize and describe the main effects ofnutritional supplementation of calcium (Ca) and vitamin D forbone health and prevention of osteoporotic fractures.Material and Methods: We carried out searches in theelectronic databases ScienceDirect, SciELO, PubMed/MEDLINE, LILACS, Portal CAPES and Google Scholar. Nationaland international papers published between 2005 and 2014were considered. The following key-words (DeCS,Descriptors in Health Sciences, BIREME) were used:osteoporosis, osteoporotic fractures, calcium, vitamin D andsupplementation. Results: Considering the inclusion andexclusion criteria, 30 articles were selected for analysis.Studies have used mean values of nutritional supplementationfrom 200 to 1200mg/day (milligrams per day) of Ca and 200to 800 IU/d (International Units per day) of vitamin D incombination, which may vary depending on the influence ofimportant variables, such as sex, age, and hormonal levelsof the individuals. Conclusions: Considering thatsupplementation of calcium and/or vitamin D contributes toreduction of bone mineral density (BMD) loss and,consequently, risk of incidence of osteoporotic bonefractures, it becomes necessary to optimize the consumptionof essential micronutrients for the maintenance of bone healthas a promising approach to reduce the damage caused bysenility...