Biomimetic three-dimensional glioma model printed in vitro for the studies of glioma cells and neurons interactions.

1The interactions between glioma cells and neurons are important for glioma progression but are rarely mimicked and recapitulated in in vitro three-dimensional (3D) models, which may affect the success rate of relevant drug research and development. In this study, an in vitro bioprinted 3D glioma model consisting of an outer hemispherical shell with neurons and an inner hemisphere with glioma cells is proposed to simulate the natural glioma. This model was produced by extrusion-based 3D bioprinting technology. The cells survival rate, morphology, and intercellular Ca2+ concentration studies were carried out up to 5 days of culturing. It was found that neurons could promote the proliferation of glioma cells around them, associate the morphological changes of glioma cells to be neuron-like, and increase the expression of intracellular Ca2+ of glioma cells. Conversely, the presence of glioma cells could maintain the neuronal survival rate and promote the neurite outgrowth. The results indicated that glioma cells and neurons facilitated each other implying a symbiotic pattern established between two types of cells during the early stage of glioma development, which were seldom found in the present artificial glioma models. The proposed bioprinted glioma model can mimic the natural microenvironment of glioma tissue, provide an in-depth understanding of cell-cell interactions, and enable pathological and pharmacological studies of glioma.

Influence of gellan gum-hydroxyapatite spongy-like hydrogels on human osteoblasts under long-term osteogenic differentiation conditions.

The scientific community has been doing significant efforts towards engineering new 3D bone models in recent years. Osteocytes are mechanosensitive cells that play significant roles in the maintenance of bone homeostasis. Currently, as far as we know, there are no 3D models that faithfully recapitulate a bone microenvironment capable of promoting the differentiation of osteoblasts towards osteocytes. Besides, in the existing models, the use of human cells does not prevail over the animal cell lines. For so, we propose a 3D model that may have important implications for ongoing efforts towards a better understanding of bone physiology and disease. The main aim of the current work was the promotion of an effective differentiation of osteoblasts into osteocytes by mean of using a 3D model composed of primary human osteoblasts (hOBs) cultured on Gellan Gum-Hydroxyapatite (GG-HAp) matrix under a long-term osteogenic culture. The results revealed that GG-HAp matrix stimulated a fast cell migration/entrapment, attachment, spreading, and mineralization. Moreover, the transition process from osteoblasts to osteocytes was confirmed by the expression of the osteogenic-related (ALP, Runx2, COL I, OC, OPN and OSX) and osteocyte-related (hPDPN) marker throughout the culture time. Overall, the developed 3D model holds a great promise for the treatment of various bone diseases, namely on diagnostic applications and for bone regeneration purposes.

Intra-articular injection of culture-expanded mesenchymal stem cells with or without addition of platelet-rich plasma is effective in decreasing pain and symptoms in knee osteoarthritis: a controlled, double-blind clinical trial.

PURPOSE: To compare the clinical and laboratory outcomes of intra-articular injections of culture-expanded bone-derived mesenchymal stem cells (MSCs) with or without platelet-rich plasma (PRP) to intra-articular corticosteroid injections for the treatment of knee osteoarthritis (OA). METHODS: Forty-seven patients with radiographic and symptomatic knee OA were randomized into three groups for intra-articular injections: autologous bone marrow-derived culture-expanded MSCs (n = 16); autologous bone marrow-derived culture-expanded MSCs + PRP (n = 14); and corticosteroid (n = 17). The outcomes were assessed by the Knee Injury and Osteoarthritis Outcome Score (KOOS) and range of motion (ROM) at baseline, 1, 2, 3, 6, 9 and 12 months and intra-articular cytokines analysis at baseline, 6 and 12 months postoperatively. RESULTS: The three groups showed significant improvement in most KOOS domains and global score at 1st month and all domains and global score at 12-month follow-up (p < 0.05). At the 1st month, only the MSCs group showed significant differences in KOOS symptoms domain (p = 0.003). The MSCs and MSCs + PRP groups showed the highest percentage of improvement in most KOOS domains and global score compared to the corticosteroid group. All three groups showed a significant reduction in intra-articular levels of human interleukin-10 cytokine, from baseline to 12 months (p < 0.05). CONCLUSION: An intra-articular injection of bone marrow-derived culture-expanded MSCs with or without the addiction of PRP is effective in improving the function and decreasing symptoms caused by knee OA at 12-month follow-up. LEVEL OF EVIDENCE: II.

Self-mineralizing Ca-enriched methacrylated gellan gum beads for bone tissue engineering.

In this study, methacrylated gellan-gum (GG-MA) heteropolysaccharide is proposed as a hydrogel for drug delivery and bone tissue engineering applications. Calcium-enriched beads obtained from the crosslinking of 1% (w/v) GG-MA solutions with 0.1 MCaCl2 were investigated, considering their intrinsic capacity to promote self-mineralization by ion binding and deposition. Indeed, when immersed in a physiological environment, the Ca-enriched beads promoted the development of a bone-like apatite layer, as confirmed by EDS and XRD chemical analysis. Additionally, the mild production process is compatible with drugs incorporation and release. After encapsulation, Dextran with different molecular weights as well as Dexamethasone 21-phosphate were efficiently released to the surrounding environment. The engineered system was also evaluated considering its biocompatibility, by means of qualitative determination of total complement activation, macrophage proliferation, cytokine release and in vitro cell culture. These experiments showed that the developed hydrogels may not stimulate a disproportionate pro-inflammatory reaction once transplanted. At last, when implanted subcutaneously in CD1 male mice up to 8 weeks, the beads were completely calcified, and no inflammatory reaction was observed. Summing up, these results show that calcium-enriched GG-MA hydrogel beads hold great potential as news tools for bone tissue regeneration and local drug delivery applications. STATEMENT OF SIGNIFICANCE: This work describes a low-cost and straightforward strategy to prepare bioactive methacrylated gellan gum (GG-MA) hydrogels, which can be used as drug delivery systems. GG-MA is a highly anionic polymer, that can be crosslinked with divalent ions, as calcium. Taking advantage of this feature, it was possible to prepare Ca-enriched GG-MA hydrogel beads. These beads display a bioactive behavior, since they promote apatite deposition when placed in physiological conditions. Studies on the immune response suggest that the developed beads do not trigger severe immune responses. Importantly, the mild processing method render these beads compliant with drug delivery strategies, paving the way for the application of dual-functional materials on bone tissue engineering.