Our purpose was to characterize human dental pulp cells isolated by various methods and to examine the behavior of cells grown under various conditions for the purpose of pulp/dentin tissue engineering and regeneration. We compared the growth of human pulp cells isolated by either enzyme digestion or the outgrowth method. Expression of dentin sialophosphoprotein, Cbfa1, and two types of collagen (I and III) in these cells was examined by Western blot or reverse transcription/polymerase chain reaction. Growth of pulp cells on dentin and in collagen gel was also characterized. We found that different isolation methods give rise to different populations or lineages of pulp cells during in vitro passage based on their collagen gene expression patterns. Cells isolated by enzymedigestion had a higher proliferation rate than those isolated by outgrowth. Pulp cells did not proliferate or grew minimally on chemically and mechanically treated dentin surface and appeared to establish an odontoblast-like morphology with a cytoplasmic process extending into a dentinal tubule as revealed by scanning electron microscopy. The contraction of the collagen matrix caused by pulp cells was dramatic: down to 34% on day 14. Our data indicate that (1) the choice of the pulp cell isolation method may affect the distribution of the obtained cell populations, (2) a treated dentin surface might still promote odontoblast differentiation, and (3) a collagen matrix may not be a suitable scaffold for pulp tissue regeneration because of the marked contraction caused by pulp cells in the matrix. The present study thus provides important information and a basis for further investigations pre-requisite to establishing pulp tissue engineering/regeneration protocols.

In this study, we prepared a blended nanofiber scaffold using synthetic and natural polymers, polyurethane (PU) and gelatin respectively, using the electrospinning method to prepare a material for wound dressing. In order to confirm the properties of this gelatin/PU blended nanofiber scaffold, we performed scanning electron microscopy, atomic force microscopy, attenuated total reflectance Fourier-transform infrared spectroscopy, thermal gravimetric analysis, contact angle, water uptake, mechanical property, recovery, and degradation tests, and cellular response. The results obtained indicate that the mean diameter of these nanofibers was uniformly electrospun and ranged from 0.4 to 2.1 microm. According to the results, when the amount of gelatin in the blended solution decreased, the contact angle increased and water uptake of the scaffold decreased concurrently. In the mechanical tests, the blended nanofibrous scaffolds were elastic, and elasticity increased as the total amount of PU increased. Moreover, as the total amount of gelatin increased, the cell proliferation increased with the same amount of culture time. Therefore, this gelatin/PU blended nanofiber scaffold has potential application for use as a wound dressing.

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Pathogen recognition receptors (PRRs) are a class of germ line-encoded receptors that recognize pathogen-associated molecular patterns (PAMPs). The activation of PRRs is crucial for the initiation of innate immunity, which plays a key role in first-line defense until more specific adaptive immunity is developed. PRRs differ in the signaling cascades and host responses activated by their engagement and in their tissue distribution. Currently identified PRR families are the Toll-like receptors (TLRs), the C-type lectin receptors (CLRs), the nucleotide-binding oligomerization domain-like receptors (NLRs), the retinoic acid-inducible gene-I-like receptors (RLRs), and the AIM2-like receptor (ALR). The environment of the dental pulp is substantially different from that of other tissues of the body. Dental pulp resides in a low compliance root canal system that limits the expansion of pulpal tissues during inflammatory processes. An understanding of the PRRs in dental pulp is important for immunomodulation and hence for developing therapeutic targets in the field of endodontics. Here we comprehensively review recent finding on the PRRs and the mechanisms by which innate immunity is activated. We focus on the PRRs expressed on dental pulp and periapical tissues and their role in dental pulp inflammation.

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This study aimed to explore effects of static magnetic fields (SMFs) of moderate intensity (3-50 mT) as biophysical stimulators of proliferation and osteoblastic differentiation of human bone marrow-derived mesenchymal stem cells (MSCs). MSCs were exposed to SMFs of three intensities: 3, 15, and 50 mT. Proliferation was assessed by cell counting and bromodeoxyuridine incorporation, and differentiation by measuring alkaline phosphatase (ALP) activity, calcium content, mineralized nodule formation, and transcripts of osteogenic markers. Moderate intensity SMFs increased cell proliferation, ALP activity, calcium release, and mineralized nodule formation in a dose- and time-dependent manner, which peaked at 15 mT. In the same manner, they upregulated expression of osteogenic marker genes such as ALP, bone sialoprotein 2 (BSP2), collagen1a1 (COL1a1), osteocalcin (OCN), osteonectin (ON), osteopontin (OPN), osterix (OSX), and runt-related transcription factor 2 (RUNX2) with peak at 15 mT after 14 or 21 days of exposure. Results demonstrate that moderate intensity SMFs promote proliferation and osteoblastic differentiation of MSCs. This effect could help to improve MSC responses during osseointegration between a dental implant and surrounding bone.

Our results demonstrate that both the EMA binding and FC OF tests are useful as screening tests for the diagnosis of HS, but the cryohemolysis test has limited use due to its false positivity in IDA, with the Hb/MCHC ratio the most useful parameter for assessing the clinical severity of HS.