PRP coating on different modified surfaces promoting the osteointegration of polyetheretherketone implant

Introduction: Polyetheretherketone (PEEK) material implants have been applied more and more clinically recently. In order to increase the osteogenic activity of PEEK material, the microstructure change of the material surface and the construction of functional microcoatings have become a hot research topic. This study investigated the ability of PEEK surfaces modified by different methods to carry Platelet-rich plasma (PRP) and the osteogenic ability of different PEEK microstructures after carrying PRP in vivo/in vitro.Methods: In this study, PEEK surfaces were modified by sulfuric acid, gaseous sulfur trioxide and sandpaper. Next, PRP from SD rats was prepared and incubated on PEEK material with different surface microstructures. Lactate dehydrogenase test, scanning electron microscope and Elisa assay was used to evaluate adhesion efficiency of PRP. Then in vitro tests such as CCK-8, ALP staining, ARS staining and RT-qPCR et al were used to further evaluate osteogenesis ability of the PRP coating on PEEK surface. Finally, The tibia defects of SD rats were established, and the new bone was evaluated by Micro-CT, HE staining, and immunofluorescence staining.Results: The sandpaper-polished PEEK with the strongest PRP carrying capacity showed the best osteogenesis. Our study found that the modified PEEK surface with PRP coating has excellent osteogenic ability and provided the basis for the interface selection of PRP for the further application of PEEK materials.Discussion: Among the three PEEK modified surfaces, due to the most PRP carrying and the strongest osteogenic ability in vitro/vivo, the frosted surface was considered to be the most suitable surface for the preparation of PRP coating

Empagliflozin alleviates atherosclerotic calcification by inhibiting osteogenic differentiation of vascular smooth muscle cells

SGLT-2 inhibitors, such as empagliflozin, have been shown to reduce the occurrence of cardiovascular events and delay the progression of atherosclerosis. However, its role in atherosclerotic calcification remains unclear. In this research, ApoE−/− mice were fed with western diet and empagliflozin was added to the drinking water for 24 weeks. Empagliflozin treatment significantly alleviated arterial calcification assessed by alizarin red and von kossa staining in aortic roots and reduced the lipid levels, while had little effect on body weight and blood glucose levels in ApoE−/− mice. In vitro studies, empagliflozin significantly inhibits calcification of primary vascular smooth muscle cells (VSMCs) and aortic rings induced by osteogenic media (OM) or inorganic phosphorus (Pi). RNA sequencing of VSMCs cultured in OM with or without empagliflozin showed that empagliflozin negatively regulated the osteogenic differentiation of VSMCs. And further studies confirmed that empagliflozin significantly inhibited osteogenic differentiation of VSMCs via qRT-PCR. Our study demonstrates that empagliflozin alleviates atherosclerotic calcification by inhibiting osteogenic differentiation of VSMCs, which addressed a critical need for the discovery of a drug-based therapeutic approach in the treatment of atherosclerotic calcification

On Submanifolds in a Riemannian Manifold with a Semi-Symmetric Non-Metric Connection

In this paper, we study submanifolds in a Riemannian manifold with a semi-symmetric non-metric connection. We prove that the induced connection on a submanifold is also semi-symmetric non-metric connection. We consider the total geodesicness and minimality of a submanifold with respect to the semi-symmetric non-metric connection. We obtain the Gauss, Cadazzi, and Ricci equations for submanifolds with respect to the semi-symmetric non-metric connection

Nonexistence of stable F-stationary maps of a functional related to pullback metrics

Abstract Let M m $M^{m}$ be a compact convex hypersurface in R m + 1 $R^{m+1}$ . In this paper, we prove that if the principal curvatures λ i $\lambda_{i}$ of M m $M^{m}$ satisfy 0 < λ 1 ≤ ⋯ ≤ λ m $0<\lambda_{1}\leq \cdots \leq \lambda_{m}$ and 3 λ m < ∑ j = 1 m − 1 λ j $3\lambda_{m}<\sum_{j=1}^{m-1}\lambda_{j}$ , then there exists no nonconstant stable F-stationary map between M and a compact Riemannian manifold when (6) or (7) holds

Improved Cell Adhesion and Osteogenesis of op-HA/PLGA Composite by Poly(dopamine)-Assisted Immobilization of Collagen Mimetic Peptide and Osteogenic Growth Peptide

A nanocomposite of poly­(lactide-<i>co</i>-glycolide) (PLGA) and hydroxyapatite (HA) with a different grafting ratio of l-lactic acid oligomer (op-HA) showed better interface compatibility, mineralization, and osteogenetic abilities. However, surface modification of the composite is crucial to improve the osteointegration for bone regeneration. In this study, a biomimetic process via poly­(dopamine) coating was utilized to prepare functional substrate surfaces with immobilized bioactive peptides that efficiently regulate the osteogenic differentiation of preosteoblasts (MC3T3-E1). Our study demonstrated that incorporation of collagen mimetic peptide significantly enhanced cell adhesion and proliferation. The immobilization of osteogenic growth peptide induced the osteodifferentiation of cells, as indicated by the alkaline phosphate activity test, quantitative real-time polymerase chain reaction analysis, and immunofluorescence staining. The mineralization on the peptide-modified substrates was also enhanced greatly. Findings from this study revealed that this biofunctionalized layer on op-HA/PLGA substrate improved mineralization and osteogenic differentiation. In conclusion, the surface modification strategy with bioactive peptides shows potential to enhance the osteointegration of bone implants