3D printed TPMS structural PLA/GO scaffold: Process parameter optimization, porous structure, mechanical and biological properties.

Bone scaffolds should have good biocompatibility and mechanical and biological properties, which are primarily by the material design, porous structure, and preparation process. In this study, we proposed polylactic acid (PLA) as the base material, graphene oxide (GO) as an enhancing filler, triply periodic minimal surface (TPMS) as a porous structure, and fused deposition modeling (FDM) 3D printing as a preparation technology to develop a TPMS structural PLA/GO scaffold and evaluate their porous structures, mechanical properties, and biological properties towards bone tissue engineering. Firstly, the influence of the FDM 3D printing process parameters on the forming quality and mechanical properties of PLA was studied by orthogonal experimental design, based on which the process parameters were optimized. Then, GO was composited with PLA, and PLA/GO nanocomposites were prepared by FDM. The mechanical tests showed that GO can effectively improve the tensile and compression strength of PLA; only by adding 0.1% GO the tensile and compression modulus was increased by 35.6% and 35.8%, respectively. Then, TPMS structural (Schwarz-P, Gyroid) scaffold models were designed and TPMS structural PLA/0.1%GO nanocomposite scaffolds were prepared by FDM. The compression test showed that the TPMS structural scaffolds had higher compression strength than the Grid structure; This was owing to the fact that the continuous curved structure of TMPS alleviated stress concentration and had a more uniform stress bearing. Moreover, cell culture indicated bone marrow stromal cells (BMSCs) showed better adhesion, proliferation, and osteogenic differentiation behaviors on the TPMS structural scaffolds as the continuous surface structure of TPMS had better connectivity and larger specific surface area. These results suggest that the TPMS structural PLA/GO scaffold has potential application in bone repair. This article suggests the feasibility of co-designing the material, structure, and technology for achieving the good comprehensive performance of polymer bone scaffolds.

Hereditary features, treatment, and prognosis of the lipoprotein glomerulopathy in patients with the APOE Kyoto mutation.

Lipoprotein glomerulopathy is a rare inherited renal disease, caused by mutation of the APOE gene, characterized by proteinuria and nephrotic syndrome with elevated serum apoE. Since its treatment and outcome are unknown, we retrospectively studied 35 patients within 31 unrelated Han families with biopsy-proven lipoprotein glomerulopathy residing in the same county in southwest China. DNA sequencing detected the APOE Kyoto mutation (p. Arg25Cys) in all patients and 28 asymptomatic relatives. All shared the same ɛ3 allele. The patients presented with proteinuria, higher total triglyceride, and serum apoE levels relative to non-carriers. The serum apoE and triglyceride levels of asymptomatic carriers were between those of the patients and non-carriers. Sixteen patients received fenofibrate treatment for over 12 months. Six reached complete remission (proteinuria under 0.3 g/day with stable serum creatinine) with intensive control of their lipid profile (normalized serum apoE and triglycerides under 100 mg/dl). Eight reached partial remission. At 3 years of follow-up, patients treated with fenofibrate had superior survival and stable renal function. Thus, fenofibrate can induce lipoprotein glomerulopathy remission and the fibrate effects depend on the degree of lipid control and baseline proteinuria. Moreover, normalization of serum apoE and triglycerides can be used to judge the efficacy of lipid-lowering treatment.