Regenerated Nerve Defects with a Nerve Conduit Containing Dental Pulp Stem Cells in Pigs: An Immunohistochemical and Electrophysiological Evaluation.

BACKGROUND: Dental pulp stem cells (DPSCs) present an exciting new tool in the field of peripheral nerve regeneration due to their close embryonic origin. In this study, we examined their potential in pigs, using biodegradable collagen conduits filled with DPSCs. To our knowledge, this is the first time DPCSs are tested for peripheral nerve regeneration in such large animal model. MATERIALS AND METHODS: The second lateral incisor was extracted from every animal's lower jaw and stem cells were isolated and cultured. The collagen nerve conduits containing the DPSCs were subsequently transplanted into the transected fifth and sixth intercostal nerves, while the seventh intercostal nerve was used as a control and no stem cells were added on the respective collagen conduit. RESULTS: A histological examination was performed on the 3rd and 6th postoperative months and showed the gradual development of neural tissue and immunohistochemical expression of neuron-specific enolase. An electrophysiological study was performed on the 6th postoperative month and showed similar potentials between the stem cell infusion region (5 ± 0.04 units) and their proximal stumps (5 ± 0.05 units) and slightly smaller potentials in the respective distal stumps (4 ± 0.045 units). CONCLUSION: The nerves where DPSCs were injected exhibited morphological and functional recovery, in contrast to the control nerves where no recovery was detected; thus, there is a first evidence of the therapeutic potential of DPSCs in peripheral nerve regeneration.

Experimental formation of dentin-like structure in the root canal implant model using cryopreserved swine dental pulp progenitor cells.

OBJECTIVES: The purpose of the present study was to present histological and immunohistochemical evidence showing the regenerative capacity of swine dental pulp stem cells (S-DPSCs) seeded on organic or synthetic scaffolds and implanted as hybrid root implants in the jaw bone of minipigs. METHODS: Immature permanent incisor teeth and unerupted premolars at the early root-forming stage were extracted from three 7-month-old minipigs, and mesenchymal stem/progenitor cells were isolated from dental pulp. Cells were cryopreserved in liquid nitrogen. A year later, new permanent incisor and premolar teeth were extracted; pulp tissue was removed; and pieces of root canals of the extracted teeth, containing collagen or Poly(lactic-co-glycolic acid) scaffolds seeded with the autologous cryopreserved DPSCs, were implanted into the fresh post-extraction socket of the mini pig jaw. The resulting constructs were harvested after 6 and 10 weeks and evaluated by histological and immunohistochemical analyses. RESULTS: Six weeks postoperatively, the central canal space of the root implants showed degrading scaffold material. New extracellular matrix had been deposited in a polar predentin-like pattern on the canal dentinal walls by cuboidal nonpolarized cells. Ten weeks postoperatively, newly formed organic matrix had been consistently deposited on the canal walls. The presence of a continuous layer of polarized cells showing typical columnar morphology adjacent to the newly deposited organic matrix was evident. CONCLUSIONS: The interactions of S-DPSCs with the dentin matrix of roots implanted in the jawbone of minipigs constitute a model to study in vivo organization and differentiation potential of DPSCs.

Effects of mastic gum Pistacia lentiscus var. Chia on innate cellular immune effectors.

BACKGROUND: The essential oil and Chios mastic gum (CMG) are natural antimicrobial agents currently broadly used in medicine owing to their antimicrobial, antioxidant, and hepatoprotective properties. The aim of this study was to investigate the effect of CMG-extracted arabinogalactan proteins (AGPs/CMG) both in vitro and in vivo, under the presence of Helicobacter pylori neutrophil-activating protein (HP-NAP), on the innate cellular immune effectors (neutrophils activations) comparing H. pylori-infected patients and healthy controls. PATIENTS AND METHODS: The in-vivo effect of AGPs/CMG under the presence of HP-NAP in neutrophil activation was investigated in five H. pylori-infected patients and three healthy volunteers who received 1 g daily consumption of CMG for 2 months. All participants did not receive any immunosuppressive medication before or during the trial; patients with infectious diseases that could modify their immunologic status were excluded. In-vitro studies with pull-down experiments to assess the effect of AGPs/CMG under the presence of HP-NAP on the neutrophil activation were also carried out. Neutrophil activation was estimated by nicotinamide adenine dinucleotide phosphate-oxidase assays and optical microscopy methods by measurement of cytochrome C reduction. RESULTS: Neutrophil activation was reduced when incubated in vitro with HP-NAP (P=0.0027) and AGP plus HP-NAP (P=0.0004) in H. pylori-positive patients who consumed AGP for 2 months. Similar results were also obtained when neutrophils were incubated with AGP plus HP-NAP (P=0.0038) in controls. Pull-down experiments showed a specific binding of AGPs to two membrane proteins of neutrophils, possibly suggesting inhibition of neutrophil activation. CONCLUSION: AGPs/CMG inhibit neutrophil activation in the presence of HP-NAP, playing a crucial role in H. pylori-associated pathologies in gastric mucosa.