Biohybrid hydrogels consisting of solubilized nanostructured pericardial matrix and electroconductive positively charged hydrazide-conjugated carbon nanotubes provide a promising material for stem cell-based cardiac tissue engineering.

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Developing porous biodegradable scaffolds through simple methods is one of the main approaches of bone tissue engineering (BTE). In this work, a novel BTE composite containing layered double hydroxides (LDH), hydroxyapatite (HA) and gelatin (GEL) was fabricated using co-precipitation and solvent-casting methods. Physiochemical characterizations showed that the chemical composition and microstructure of the scaffolds were similar to the natural spongy bone. Interconnected macropores ranging over 100 to 600μm were observed for both scaffolds while the porosity of 90±0.12% and 92.11±0.15%, as well as, Young's modulus of 19.8±0.41 and 12.5±0.35GPa were reported for LDH/GEL and LDH-HA/GEL scaffolds, respectively. The scaffolds were degraded in deionized water after a month. The SEM images revealed that between two scaffolds, the LDH-HA/GEL with needle-like secondary HA crystals showed better bioactivity. According to the alkaline phosphatase activity and Alizarin red staining results, LDH-HA/GEL scaffolds demonstrated better bone-specific activities comparing to LDH/Gel scaffold as well as control sample (P<0.05). The rabbit adipose stem cells (ASCs) were extracted and cultured, then seeded on the LDH-HA/GEL scaffolds after confluence. Three groups of six adult rabbits were prepared: the scaffold+ASCs group, the empty scaffold group and the control group. The critical defects were made on the left radius and the scaffolds with or without ASCs were implanted there while the control group was left without any treatment. All animals were sacrificed after 12weeks. Histomorphometric results showed that the regeneration of defects was accelerated by scaffold implantation but ASC-seeding significantly improved the quality of new bone formation (P<0.05). The results confirmed the good performance of LDH-HA/GEL scaffold to induce bone regeneration.

BackgroundLung diseases such as acute respiratory distress syndrome (ARDS) have a high incidence worldwide. The current drug therapies for ARDS have supportive effects, making them inefficient. New methods such as stromal cell therapy are needed for this problem.MethodsThis research was performed with ten New Zealand rabbits in two groups. Bone marrow aspiration was performed on the treated group, and mesenchymal stem cells were isolated and cultured. The experimental model of ARDS was induced using LPS from Escherichia coli strain O55:B5. Then, 1010 bone marrow mesenchymal stem cells (BM-MSCs) were autologously transplanted intrapulmonary in the treatment group, and 1–2 ml of PBS in the control group. The clinical signs, computed tomographic (CT) scans, echocardiography, blood gas analysis, complete blood count, and cytokine levels were measured before and at 3, 6, 12, 24, 48, 72, and 168 h after BM-MSC transplant. Finally, the rabbits were killed, and histopathological examination was performed.ResultsThe results showed that BM-MSCs decreased the severity of clinical symptoms, the number of white blood cells and heterophils in the blood, the total cell count, and number of heterophils and macrophages in bronchoalveolar lavage, and balanced the values of arterial blood gases (increase in partial pressure of oxygen and O2 saturation and decrease in the partial pressure of carbon dioxide). They also downregulated the tumor necrosis factor (TNF)-α and interleukin (IL)-6 concentrations and increased the IL-10 concentrations at different times compared with time 0 and in the control group, significantly. In the CT scan, a significant decrease in the Hounsfield units and total lung volume was found by echocardiography, and in comparing the two groups, a significant difference in the parameters was noticed. The histopathology demonstrated that the BM-MSCs were able to reduce the infiltration of inflammatory cells and pulmonary hemorrhage and edema.ConclusionsThis study indicated that BM-MSCs play a significant role in the repair of lung injury.Electronic supplementary materialThe online version of this article (10.1186/s13054-018-2272-x) contains supplementary material, which is available to authorized users.

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Our study has shown that carbomer 940 hydrogel is a nontoxic biomaterial, which improved tissue perfusion and decreased the area of necrotic tissue in burn wounds. Application of this biomaterial in treatment of burn injuries deserves further studies.

Minimal direct electrical current, which can produce an electrical field around the implant, can increase the amount of bone formation and decrease the time of osseointegration.

Osteogenic differentiation is enhanced by many inductive factors including biochemical agents, biomechanical stresses, and electrical stimulation. Regularly studies have focused on one factor at a time, while synergies can promote more effective and functional osteogenesis. Herein, for the first time, functional synergism between application of electrical stimulation and HA nanoparticles was evaluated in osteogenic differentiation. Prepared electrospun biocompatible conductive scaffold by amalgamating chitosan, aniline-pentamer, and hydroxyapatite incorporation was seeded by human bone-marrow-derived mesenchymal stem cells. The cells seeded on the scaffolds with and without hydroxyapatite were exposed to electrical stimulation and subsequently, osteogenic molecular markers and related signaling pathways were investigated. In general, all investigated osteogenic markers (osteocalcin, alkaline phosphatase, osteonectin, and Runx2) were upregulated transcriptionally in the cells seeded on the chitosan-embedded scaffolds. Separate utilization of electrical stimulation or hydroxyapatite-enhanced osteogenesis, while the cells exposed to both stimulators simultaneously, expressed higher levels of some of osteogenic genes significantly. Considering the functions and the positions of the markers in osteogenic signaling pathways, it can be concluded that HA might cooperate in the allocation of stem cells to osteoprogenitors in the early phase of osteogenesis while electrical stimulation helps committed cells with maturation and acquiring functional phenotypes. Altogether investigation of the synergism between different stimulators and exploiting the interactions in an optimized manner could lead to more efficient osteogenesis protocol for effective bone regeneration and tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1200-1210, 2018.