Acute-on-chronic kidney injury at hospital discharge is associated with long-term dialysis and mortality

Existing chronic kidney disease (CKD) is among the most potent predictors of postoperative acute kidney injury (AKI). Here we quantified this risk in a multicenter, observational study of 9425 patients who survived to hospital discharge after major surgery. CKD was defined as a baseline estimated glomerular filtration rate <45ml/min per 1.73m2. AKI was stratified according to the maximum simplified RIFLE classification at hospitalization and unresolved AKI defined as a persistent increase in serum creatinine of more than half above the baseline or the need for dialysis at discharge. A Cox proportional hazard model showed that patients with AKI-on-CKD during hospitalization had significantly worse long-term survival over a median follow-up of 4.8 years (hazard ratio, 3.3) than patients with AKI but without CKD. The incidence of long-term dialysis was 22.4 and 0.17 per 100 person-years among patients with and without existing CKD, respectively. The adjusted hazard ratio for long-term dialysis in patients with AKI-on-CKD was 19.8 compared to patients who developed AKI without existing CKD. Furthermore, AKI-on-CKD but without kidney recovery at discharge had a worse outcome (hazard ratios of 4.6 and 213, respectively) for mortality and long-term dialysis as compared to patients without CKD or AKI. Thus, in a large cohort of postoperative patients who developed AKI, those with existing CKD were at higher risk for long-term mortality and dialysis after hospital discharge than those without. These outcomes were significantly worse in those with unresolved AKI at discharge

PARTICLE SIZE AND TEMPERATURE EFFECTS ON ANTIOXIDANT BY-PRODUCT ISOLATED FROM LEAF GUM EXTRACT OF MESONA PROCUMBENS HEMSL

A water extraction procedure for isolating antioxidants from dried aerial tissue of Mesona procumbens Hemsl. prior to leaf gum/starch composite gel preparation was developed, along with investigation of its antioxidative activities. The results showed that the highest contents of total phenolics and flavonoids were isolated from the dried aerial tissues when they were extracted under 100C for 2 h using the dried materials ground to 75-µm particle size. This water extract also had the highest antioxidative responses, as determined by 2,2-diphenyl-1-picrylhydrazy scavenging, ferric reducing antioxidant power, 2,2-azino-bis[3-ethyl-benzthiazoline-6-sulfonic acid] radical-scavenging, superoxide-scavenging and lipid peroxidation inhibition activities. The water extract produced under 100C condition also showed the greatest gel hardness and gel strength (prepared by using 2% cassava starch). Thus, the extracted antioxidants from aerial tissues of M. procumbens Hemsl. could be considered for some commercial applications

Mesoporous calcium silicate nanoparticles with drug delivery and odontogenesis properties

[[abstract]]Introduction: Calcium silicate (CS) –based materials play an important role in the development of endodontic materials that induce bone/cementum tissue regeneration and inhibit bacterial viability. The aim of this study was to prepare novel mesoporous CS (MesoCS) nanoparticles that have osteogenic, drug delivery, and antibacterial characteristics for endodontic materials and also have an excellent ability to develop apatite mineralization. Methods: The MesoCS nanoparticles were prepared using sol-gel methods. In addition, the mesoporous structure, specific surface area, pore volume, and morphology of the MesoCS nanoparticles were analyzed. The apatite mineralization ability, in vitro odontogenic differentiation, drug delivery, and antibacterial properties of the MesoCS nanoparticles were further investigated. Results: The results indicate that the 200-nm–sized MesoCS nanoparticles synthesized using a facile template method exhibited a high specific surface area and pore volume with internal mesopores (average pore size = 3.05 nm). Furthermore, the MesoCS nanoparticles can be used as drug carriers to maintain sustained release of gentamicin and fibroblast growth factor-2 (FGF-2). The MesoCS-loaded FGF-2 might stimulate more odontogenic-related protein than CS because of the FGF-2 release. Conclusions: Based on this work, it can be inferred that MesoCS nanoparticles are potentially useful endodontic materials for biocompatible and osteogenic dental pulp tissue regenerative materials. (J Endod 2017;43:69–76

Laser Sintered Magnesium-Calcium Silicate/Poly-ε-Caprolactone Scaffold for Bone Tissue Engineering

In this study, we manufacture and analyze bioactive magnesium–calcium silicate/poly-ε-caprolactone (Mg–CS/PCL) 3D scaffolds for bone tissue engineering. Mg–CS powder was incorporated into PCL, and we fabricated the 3D scaffolds using laser sintering technology. These scaffolds had high porosity and interconnected-design macropores and structures. As compared to pure PCL scaffolds without an Mg–CS powder, the hydrophilic properties and degradation rate are also improved. For scaffolds with more than 20% Mg–CS content, the specimens become completely covered by a dense bone-like apatite layer after soaking in simulated body fluid for 1 day. In vitro analyses were directed using human mesenchymal stem cells (hMSCs) on all scaffolds that were shown to be biocompatible and supported cell adhesion and proliferation. Increased focal adhesion kinase and promoted cell adhesion behavior were observed after an increase in Mg–CS content. In addition, the results indicate that the Mg–CS quantity in the composite is higher than 10%, and the quantity of cells and osteogenesis-related protein of hMSCs is stimulated by the Si ions released from the Mg–CS/PCL scaffolds when compared to PCL scaffolds. Our results proved that 3D Mg–CS/PCL scaffolds with such a specific ionic release and good degradability possessed the ability to promote osteogenetic differentiation of hMSCs, indicating that they might be promising biomaterials with potential for next-generation bone tissue engineering scaffolds

The Synergistic Effect of Cyclic Tensile Force and Periodontal Ligament Cell-Laden Calcium Silicate/Gelatin Methacrylate Auxetic Hydrogel Scaffolds for Bone Regeneration

The development of 3D printing technologies has allowed us to fabricate complex novel scaffolds for bone regeneration. In this study, we reported the incorporation of different concentrations of calcium silicate (CS) powder into fish gelatin methacrylate (FGelMa) for the fabrication of CS/FGelMa auxetic bio-scaffolds using 3D printing technology. Our results showed that CS could be successfully incorporated into FGelMa without influencing the original structural components of FGelMa. Furthermore, it conveyed that CS modifications both the mechanical properties and degradation rates of the scaffolds were improved in accordance with the concentrations of CS upon modifications of CS. In addition, the presence of CS enhanced the adhesion and proliferation of human periodontal ligament cells (hPDLs) cultured in the scaffold. Further osteogenic evaluation also confirmed that CS was able to enhance the osteogenic capabilities via activation of downstream intracellular factors such as pFAK/FAK and pERK/ERK. More interestingly, it was noted that the application of extrinsic biomechanical stimulation to the auxetic scaffolds further enhanced the proliferation and differentiation of hPDLs cells and secretion of osteogenic-related markers when compared to CS/FGelMa hydrogels without tensile stimulation. This prompted us to explore the related mechanism behind this interesting phenomenon. Subsequent studies showed that biomechanical stimulation works via YAP, which is a biomechanical cue. Taken together, our results showed that novel auxetic scaffolds could be fabricated by combining different aspects of science and technology, in order to improve the future chances of clinical applications for bone regeneration

Physicochemical properties and biocompatibility of silica doped β-tricalcium phosphate for bone cement

AbstractBackground/purposeβ-Tricalcium phosphate (β-TCP) is an osteoconductive material. Earlier reports revealed that silica plays an important role in bone mineralization, and its incorporation would enhance the biocompatibility of implants.Materials and methodsIn this study, silica doping at various concentrations (0 wt.%, 10 wt.%, 20 wt.%, and 30 wt.%) was performed. Si-â-TCP was obtained upon calcining the as-prepared powders at 1400°C. To check its effectiveness, different Si-â-TCP samples were prepared to make new bioactive and biodegradable biocomposites for bone repair. Formation of bonelike apatite, the diametral tensile strength, ions released, and weight loss of composites were considered before and after immersion in simulated body fluid. We also examined the behavior of human dental pulp cells (hDPCs) cultured on these materials.ResultsThe results showed that the apatite deposition ability of the β-TCP was enhanced as the Si content was increased. For composites with >20% Si content, the apatite layer covered the samples. At the end of the immersion point, weight losses of 52%, 45%, 33%, and 26% were observed for the β-TCP containing 0%, 10%, 20%, and 30% Si, respectively. In vitro cell experiments showed that the Si-rich cement promotes hDPC proliferation and differentiation. However, when the Si content in the cement is >20%, the amount of cells and osteogenesis protein of hDPCs were stimulated by Si released from Si-β-TCP.ConclusionThe degradation of β-TCP and osteogenesis of Si give us a strong reason to believe that these Si-based cements may prove to be promising bone repair materials

Human Dental Pulp Cells Responses to Apatite Precipitation from Dicalcium Silicates

Unraveling the mechanisms behind the processes of cell attachment and the enhanced proliferation that occurs as a response to the presence of calcium silicate-based materials needs to be better understood so as to expand the applications of silicate-based materials. Ions in the environment may influence apatite precipitation and affect silicate ion release from silicate-based materials. Thus, the involvement of apatite precipitate in the regulation of cell behavior of human dental pulp cells (hDPCs) is also investigated in the present study, along with an investigation of the specific role of cell morphology and osteocalcin protein expression cultured on calcium silicate (CS) with different Dulbecco’s modified Eagle’s medium (DMEM). The microstructure and component of CS cement immersion in DMEM and P-free DMEM are analyzed. In addition, when hDPCs are cultured on CS with two DMEMs, we evaluate fibronectin (FN) and collagen type I (COL) secretion during the cell attachment stage. The facilitation of cell adhesion on CS has been confirmed and observed both by scanning with an electron microscope and using immunofluorescence imaging. The results indicate that CS is completely covered by an apatite layer with tiny spherical shapes on the surface in the DMEM, but not in the P-free DMEM. Compared to the P-free DMEM, the lower Ca ion in the DMEM may be attributed to the formation of the apatite on the surfaces of specimens as a result of consumption of the Ca ion from the DMEM. Similarly, the lower Si ion in the CS-soaked DMEM is attributed to the shielding effect of the apatite layer. The P-free DMEM group releases more Si ion increased COL and FN secretion, which promotes cell attachment more effectively than DMEM. This study provides new and important clues regarding the major effects of Si-induced cell behavior as well as the precipitated apatite-inhibited hDPC behavior on these materials