RESUMEN
As highlighted by the 'Global Burden of Disease Study 2019' conducted by the World Health Organization, ensuring fair access to medical care through affordable and targeted treatments remains crucial for an ethical global healthcare system. Given the escalating demand for advanced and urgently needed solutions in regenerative bone procedures, the critical role of biopolymers emerges as a paramount necessity, offering a groundbreaking avenue to address pressing medical needs and revolutionize the landscape of bone regeneration therapies. Polymers emerge as excellent solutions due to their versatility, making them reliable materials for 3D printing. The development and widespread adoption of this technology would impact production costs and enhance access to related healthcare services. For instance, in dentistry, the use of commercial polymers blended with ß-tricalcium phosphate (TCP) is driven by the need to print a standardized product with osteoconductive features. However, modernization is required to bridge the gap between biomaterial innovation and the ability to print them through commercial printing devices. Here we showed, for the first time, the metabolic behavior and the lineage commitment of bone marrow-derived multipotent mesenchymal cells (MSCs) on the 3D-printed substrates poly(e-caprolactone) combined with 20% tricalcium phosphate (PCL + 20% ß-TCP) and L-polylactic acid (PLLA) combined with 10% hydroxyapatite (PLLA + 10% HA). Although there are limitations in printing additive-enriched polymers with a predictable and short half-life, the tested 3D-printed biomaterials were highly efficient in supporting osteoinductivity. Indeed, considering different temporal sequences, both 3D-printed biomaterials resulted as optimal scaffolds for MSCs' commitment toward mature bone cells. Of interest, PLLA + 10% HA substrates hold the confirmation as the finest material for osteoinduction of MSCs.
RESUMEN
INTRODUCTION: Standard care for malignant tumors arising next to a bone structure is surgical removal with safety margins, followed by external beam radiotherapy (EBRT). Complete tumor removal can result in large bone defects. A two-step bone reconstruction technique using the induced membrane (IM) technique has proven its efficacy to bridge gap nonunion. During the first step, a spacer is placed in the bone gap. The spacer then is removed and the IM around it is filled with autologous cancellous bone graft. However, the feasibility of this technique with the addition of adjuvant EBRT between the two reconstruction steps has not yet been studied. Polymethyl methacrylate (PMMA) used to be the standard spacer material for the first step. Silicone spacers could replace them owing to their good behavior when submitted to EBRT and their easier removal from the surgical site during the second step. The aim of this study was to evaluate the influence of EBRT on the histological and biochemical properties of IM induced using PMMA or silicone as spacer. MATERIALS AND METHODS: The analyses were performed on PMMA- or silicone-IM with and without EBRT in a 6-mm bilateral femoral defect in 32 rats. Thickness and vessel content were measured in both groups. Bone morphogenetic protein 2 (BMP2) and vascular endothelial growth factor (VEGF) content in lysates of the crushed membranes were measured by enzyme immunoassay. Finally, alkaline phosphatase activity was analyzed in human bone marrow stromal cell cultures in contact with the same lysates. RESULTS: EBRT did not change the histological structure of the cellular internal layer or the fibrous outer layer. The nature of the spacer only influenced IM thickness, PMMA-IM with external radiotherapy being significantly thicker. EBRT decreased the vascular density of IM but was less effective on VEGF/BMP2 production. In vitro, IM could have an osteoinductive potential on human bone marrow stem cells. CONCLUSION: EBRT did not modify the histological properties of IMs but decreased their vascular density. VEGF and BMP2 production within IMs was not affected by EBRT. Silicone spacers are able to induce membranes with similar histological characteristics to PMMA-IM.
Asunto(s)
Huesos/metabolismo , Huesos/patología , Polimetil Metacrilato/química , Siliconas/química , Animales , Proteína Morfogenética Ósea 2/metabolismo , Línea Celular , Femenino , Humanos , Inmunohistoquímica , Cuidados Posoperatorios , Ratas , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Objective To search a better novae biomaterial applied to guide bone regeneration for promoting the healing of acute bone trauma by the experimental study of Haversian remodeling.Method Circular bone defects of 5mm diameter were created in tibias and the corners of mandibles in 36 rabbits.The defects were covered with calcium alginate film (CAF) in the experimental group, collagen membrane (CM)and no membrane (blank) in the control groups respectively. Healing conditions were analyzed using gross inspection, and histological and immunohistochemical studies after 1, 2, 4, 6 and 8 weeks respectively.Results The experimental group appeared more and earlier Haversian remodeling with osteoinductive factors leading to better bone regeneration. The control groups showed more macrophages with CM absorbed slowly, weak and delayed Haversian remodeling, and less osteoinductive factors ( P ＜ 0.05) in the early stage.Conclusions Calcium alginate film, as a relatively cheaper biomaterial, provided better effect than the collagen membrane on guided bone regeneration, because of its better Haversian remodeling and more content of osteoinductive factors shown in this experiment.