Cytocompatibility and osteogenic differentiation of stem cells from human exfoliated deciduous teeth with cotton cellulose nanofibers for tissue engineering and regenerative medicine.

Cellulose nanofibers (CNFs) are natural polymers with physical-chemical properties that make them very attractive for modulating stem cell differentiation, a crucial step in tissue engineering and regenerative medicine. Although cellulose is cytocompatible, when materials are in nanoscale, they become more reactive, needing to evaluate its potential toxic effect to ensure safe application. This study aimed to investigate the cytocompatibility of cotton CNF and its differentiation capacity induction on stem cells from human exfoliated deciduous teeth. First, the cotton CNF was characterized. Then, the cytocompatibility and the osteogenic differentiation induced by cotton CNF were examined. The results revealed that cotton CNFs have about 6-18 nm diameters, and the zeta potential was -10 mV. Despite gene expression alteration, the cotton CNF shows good cytocompatibility. The cotton CNF induced an increase in phosphatase alkaline activity and extracellular matrix mineralization. The results indicate that cotton CNF has good cytocompatibility and can promote cell differentiation without using chemical inducers, showing great potential as a new differentiation inductor for tissue engineering and regenerative medicine applications.

Cytocompatibility of carboxylated multi-wall carbon nanotubes in stem cells from human exfoliated deciduous teeth.

Carboxylated multi-wall carbon nanotube (MWCNT-COOH) presents unique properties due to nanoscale dimensions and permits a broad range of applications in different fields, such as bone tissue engineering and regenerative medicine. However, the cytocompatibility of MWCNT-COOH with human stem cells is poorly understood. Thus, studies elucidating how MWCNT-COOH affects human stem cell viability are essential to a safer application of nanotechnologies. Using stem cells from the human exfoliated deciduous teeth model, we have evaluated the effects of MWCNT-COOH on cell viability, oxidative cell stress, and DNA integrity. Results demonstrated that despite the decreased metabolism of mitochondria, MWCNT-COOH had no toxicity against stem cells. Cells maintained viability after MWCNT-COOH exposure. MWCNT-COOH did not alter the superoxide dismutase activity and did not cause genotoxic effects. The present findings are relevant to the potential application of MWCNT-COOH in the tissue engineering and regenerative medicine fields.

Stem cells from human-exfoliated deciduous teeth reduce tissue-infiltrating inflammatory cells improving clinical signs in experimental autoimmune encephalomyelitis.

Stem cells from human exfoliated deciduous teeth (SHED) have great therapeutic potential and here, by the first time, we evaluated their immunomodulatory effect on experimental model of autoimmune encephalomyelitis (EAE). Specifically, we investigated the effect of SHED administration on clinical signs and cellular patterns in EAE model using Foxp3 GFP + transgenic mice (C57Bl/6-Foxp3GFP). The results showed that SHED infusion ameliorated EAE clinical score with reduced number of infiltrating IFN-γ+CD8+, IL-4+CD8+, IFN-γ+CD4+ and IL-4+CD4+ T cells into the central nervous system (CNS). In addition, we observed that SHED promoted a significant increase in CD4+FOXP3+ T cells population in the spleen of EAE-affected animals. Taken together, our results provide strong evidence that SHED can modulate peripherally the CD4+ T cell responses suggesting that SHED would be explored as part of cellular therapy in autoimmune diseases associated with CNS.

Early transplantation of human immature dental pulp stem cells from baby teeth to golden retriever muscular dystrophy (GRMD) dogs: Local or systemic?

BACKGROUND: The golden retriever muscular dystrophy (GRMD) dogs represent the best available animal model for therapeutic trials aiming at the future treatment of human Duchenne muscular dystrophy (DMD). We have obtained a rare litter of six GRMD dogs (3 males and 3 females) born from an affected male and a carrier female which were submitted to a therapeutic trial with adult human stem cells to investigate their capacity to engraft into dogs muscles by local as compared to systemic injection without any immunosuppression. METHODS: Human Immature Dental Pulp Stem Cells (hIDPSC) were transplanted into 4 littermate dogs aged 28 to 40 days by either arterial or muscular injections. Two non-injected dogs were kept as controls. Clinical translation effects were analyzed since immune reactions by blood exams and physical scores capacity of each dog. Samples from biopsies were checked by immunohistochemistry (dystrophin markers) and FISH for human probes. RESULTS AND DISCUSSION: We analyzed the cells' ability in respect to migrate, engraftment, and myogenic potential, and the expression of human dystrophin in affected muscles. Additionally, the efficiency of single and consecutive early transplantation was compared. Chimeric muscle fibers were detected by immunofluorescence and fluorescent in situ hybridisation (FISH) using human antibodies and X and Y DNA probes. No signs of immune rejection were observed and these results suggested that hIDPSC cell transplantation may be done without immunosuppression. We showed that hIDPSC presented significant engraftment in GRMD dog muscles, although human dystrophin expression was modest and limited to several muscle fibers. Better clinical condition was also observed in the dog, which received monthly arterial injections and is still clinically stable at 25 months of age. CONCLUSION: Our data suggested that systemic multiple deliveries seemed more effective than local injections. These findings open important avenues for further researches.