Purpose Bone consolidation after severe trauma is the most challenging task in orthopedic surgery. This study aimed to develop biomimetic composite for coating Ti implants. Afterwards, these implants were tested in vivo to assess bone consolidation in the absence or the presence of high-frequency pulsed electromagnetic short-waves (HF-PESW). Materials Biomimetic coating was successfully developed using multi-substituted hydroxyapatite (ms-HAP) functionalized with collagen (ms-HAP/COL), embedded into poly-lactic acid (PLA) matrix (ms-HAP/COL@PLA), and subsequently covered with self-assembled COL layer (ms-HAP/COL@PLA/COL, named HAPc). Methods For in vivo evaluation, 32 Wistar albino rats were used in four groups: control group (CG) with Ti implant; PESW group with Ti implant+HF-PESW; HAPc group with Ti implant coated with HAPc; HAPc+PESW group with Ti implant coated with HAPc+HF-PESW. Left femoral diaphysis was fractured and fixed intramedullary. From the first post-operative day, PESW and HAPc+PESW groups underwent HF-PESW stimulation for 14 consecutive days. Biomimetic coating was characterized by XRD, HR-TEM, SEM, EDX and AFM. Results Osteogenic markers (ALP and osteocalcin) and micro-computed tomography (CT) analysis (especially bone volume/tissue volume ratio results) indicated at 2 weeks the following group order: HAPc+PESW>HAPc≈PESW ( P >0.05) and HAPc+PESW>control ( P <0.05), indicating the higher values in HAPc+PESW group compared to CG. The fracture-site bone strength showed, at 2 weeks, the highest average value in HAPc+PESW group. Moreover, histological analysis revealed the most abundant COL fibers assembled in dense bundles in HAPc-PESW group. At 8 weeks, micro-CT indicated higher values only in HAPc+PESW group vs CG ( P <0.05), and histological results showed a complete-healed fracture in groups: HAPc+PESW, HAPc and PESW, but with more advanced bone remodeling in HAPc+PESW group. Conclusion Using Ti implants coated by HAPc jointly with HF-PESW stimulation positively influenced the bone consolidation process, especially in its early phase, thus potentially providing a superior strategy for clinical applications.

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The goal of this study was to analyze the response of osteoblasts cultured on strontium substituted hydroxyapatites (HAP-Sr) of well-defined high crystallinity deposited as thin films on glass plates. Up to now, this aspect has not been carefully investigated in the context of bio-ceramics. In this study, we present the osteoblasts activity on synthesized HAP-Sr for different amounts of strontium substitution for calcium within the hydroxyapatite (Ca10(PO4)6(OH)2, HAP) lattice, namely HAP-5%Sr, HAP-10%Sr, HAP-15%Sr and HAP-59.2%Sr (Sr-HAP, of formula Sr10(PO4)6(OH)2), in comparison with stoichiometric pure HAP, chosen as control. Each bio-ceramic was deposited as thin multilayers self-assembled substrate (scaffold) and chemically bonded to the surface of glass plates. These coatings revealed by AFM and SEM imaging a granular texture formed from bio-ceramic nanoparticles. They possessed a high degree of crystallinity, i.e. 68% to 86%, depending on the Sr amount within the HAP lattice, as judged by XRD. Osteoblasts were cultured up to 21days and displayed enhanced adhesion and proliferation particularly evidenced on relatively high strontium contents (especially 5 and 10 weight %, determined by SEM-EDX), where the alkaline phosphatase activity and type I collagen were strongly evidenced. These bio-ceramics showed a high in vitro biocompatibility stimulating the activity of osteoblasts in the process of bone formation. These nano biomaterials can have applications in orthopedic and dental surgery improving the osteointegration as coatings of bone implants as well as for bone repair and regeneration.

Background The aim was to assess the effects of periodontal disease in promoting liver fibrosis in a rat model of ligature‐induced periodontitis. Methods Twenty‐four Wistar rats were divided into four groups: control (CTRL), experimental periodontitis group at day 7 (PER7), at day 14 (PER14), at day 21 (PER21). Experimental periodontitis was induced by the placement of a silk ligature around mandibular incisors. The following parameters were assessed: gingival index, tooth mobility; liver status, and portal vein caliber by ultrasound examination; bone retraction, bone mineral density (BMD), bone volume/tissue volume (BV/TV) by micro‐CT analysis; aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT); oxidative stress (malondialdehyde [MDA], reduced glutathione/oxidative glutathione ratio [GSH/GSSG]), and matrix metalloproteinase‐8 (MMP‐8) levels; and histopathological evaluation of periodontal and liver tissues. Results Periodontal parameters showed the development of periodontitis in experimental groups. Micro‐CT results indicates an increase of bone retraction and BMD values and a decrease of BV/TV value in PER groups. Liver fibrosis could not be diagnosed with ultrasound examination in any of the groups. Elevated levels of ASAT and ALAT in PER groups compared with CTRL group were found. MDA have indicated elevated levels and a decrease of GSH/GSSG ratio in PER group compared with the CTRL group. Levels of MMP‐8 have indicated high values in PER21 compared with the other groups. Histological analysis of the periodontal and liver tissues sustains the link between periodontal and hepatic injury. Conclusion This study demonstrates a positive correlation between periodontal lesions and liver disease. Periodontitis may be an independent risk factor for liver fibrosis.