PURPOSE: The purpose of this in vitro study was to analyze the toxicity of acrylate-based restorative composite resins filled with hydroxyapatite and a silica/hydroxyapatite combination.
MATERIAL AND METHODS: Five different restorative materials based on bisphenol A-glycidyl methacrylate (bis-GMA) and tri-ethylene glycol dimethacrylate (TEGDMA) were developed: unfilled (H0), hydroxyapatite-filled (H30, H50), and silica/hydroxyapatite-filled (SH30, SH50) composite resins. These were tested for in vitro cytotoxicity by using human bone marrow mesenchymal stromal cells. Surface morphology, elemental composition, and functional groups were determined by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), and Fourier-transformed infrared spectroscopy (FTIR). The spectra normalization, baseline corrections, and peak integration were carried out by OPUS v4.0 software.
RESULTS: Both in vitro cytotoxicity results and SEM analysis indicated that the composite resins developed were nontoxic and supported cell adherence. Elemental analysis with EDX revealed the presence of carbon, oxygen, calcium, silicon, and gold, while the presence of methacrylate, hydroxyl, and methylene functional groups was confirmed through FTIR analysis.
CONCLUSIONS: The characterization and compatibility studies showed that these hydroxyapatite-filled and silica/hydroxyapatite-filled bis-GMA/TEGDMA-based restorative composite resins are nontoxic to human bone marrow mesenchymal stromal cells and show a favorable biologic response, making them potential biomaterials.
METHODS: MSC were isolated from human bone marrow mononuclear cells based on plastic adherent properties and expanded in vitro in the culture medium. Human mesenchymal stem cells (hMSC) were characterised using microscopy, immunophenotyping, and their ability to differentiate into adipocytes, chondrocytes, and osteocytes. hMSC were then injected into athymic mice, which had induced glomerulonephropathy (GN).
RESULTS: Test mice (induced GN and infused hMSC) were shown to have anti-human CD105(+) cells present in the kidneys and were also positive to anti-human desmin, a marker for mesangial cells. Furthermore, immunofluorescence assays also demonstrated that anti-human desmin(+) cells in the glomeruli of these test mice were in the proliferation stage, being positive to anti-human Ki-67.
CONCLUSIONS: These findings indicate that hMSC found in renal glomeruli differentiated into mesangial cells in vivo after glomerular injury occurred.
METHODS: Sprague-Dawley rats were injected with CCl4 for 8 weeks to induce irreversible liver fibrosis. Ex-vivo expanded, pooled human MSCs obtained from BM and WJ were intravenously administered into rats with liver fibrosis at a dose of 10 × 106 cells/animal. Sham control and vehicle-treated animals served as negative and disease controls, respectively. The animals were sacrificed at 30 and 70 days after cell transplantation and hepatic-hydroxyproline content, histopathological, and immunohistochemical analyses were performed.
RESULTS: BM-MSCs treatment showed a marked reduction in liver fibrosis as determined by Masson's trichrome and Sirius red staining as compared to those treated with the vehicle. Furthermore, hepatic-hydroxyproline content and percentage collagen proportionate area were found to be significantly lower in the BM-MSCs-treated group. In contrast, WJ-MSCs treatment showed less reduction of fibrosis at both time points. Immunohistochemical analysis of BM-MSCs-treated liver samples showed a reduction in α-SMA+ myofibroblasts and increased number of EpCAM+ hepatic progenitor cells, along with Ki-67+ and human matrix metalloprotease-1+ (MMP-1+) cells as compared to WJ-MSCs-treated rat livers.
CONCLUSIONS: Our findings suggest that BM-MSCs are more effective than WJ-MSCs in treating liver fibrosis in a CCl4-induced model in rats. The superior therapeutic activity of BM-MSCs may be attributed to their expression of certain MMPs and angiogenic factors.