Therapeutic applications of dental pulp stem cells in regenerating dental,periodontal and oral-related structures

Dental pulp stem cells (DPSCs) have emerged as a promising tool with greatpotential for use in tissue regeneration and engineering. Some of the mainadvantages of these cells are their multifaceted differentiation capacity, along withtheir high proliferation rate, a relative simplicity of extraction and culture thatenables obtaining patient-specific cell lines for their use in autologous celltherapy. PubMed, Scopus and Google Scholar databases were searched forrelevant articles related to the use of DPSCs in regeneration of dentin-pulpcomplex (DPC), periodontal tissues, salivary gland and craniomaxillofacial bonedefects. Few studies were found regarding the use of DPSCs for regeneration ofDPC. Scaffold-based combined with DPSCs isolated from healthy pulps was thestrategy used for DPC regeneration. Studies involved subcutaneous implantationof scaffolds loaded with DPSCs pretreated with odontogenic media, or performedon human tooth root model as a root slice. Most of the studies were related toperiodontal tissue regeneration which mainly utilized DPSCs/secretome. Forperiodontal tissues, DPSCs or their secretome were isolated from healthy orinflamed pulps and they were used either for preclinical or clinical studies.Regarding salivary gland regeneration, the submandibular gland was the onlymodel used for the preclinical studies and DPSCs or their secretome were isolatedonly from healthy pulps and they were used in preclinical studies. Likewise,DPSCs have been studied for craniomaxillofacial bone defects in the form ofmandibular, calvarial and craniofacial bone defects where DPSCs were isolatedonly from healthy pulps for preclinical and clinical studies. From the previousresults, we can conclude that DPSCs is promising candidate for dental and oraltissue regeneration.

Human dental pulp stem/stromal cells in clinical practice

Dental pulp stem/stromal cells(DPSCs)are fibroblast-like,neural crest-derived,and multipotent cells that can differentiate into several lineages.They are relatively easy to isolate from healthy and inflamed pulps,with little ethical concerns and can be successfully cryopreserved and thawed.The therapeutic effects of DPSCs derived from animal or human sources have been extensively studied through in-vitro and in-vivo animal experiments and the findings indicated that DPSCs are effective not only for dental diseases but also for systemic diseases.Understanding that translational research is a critical step through which the fundamental scientific discoveries could be translated into applicable diagnostics and therapeutics that directly benefit humans,several clinical studies were carried out to generate evidence for the efficacy and safety of autogenous or allogeneic human DPSCs(hDPSCs)as a treatment modality for use in cell-based therapy,regenerative medicine/dentistry and tissue engineering.In clinical medicine,hDPSCs were effective for treating acute ischemic stroke and human exfoliated deciduous teeth-conditioned medium(SHED-CM)repaired vascular damage of the corpus cavernous,which is the main cause of erectile dysfunction.Whereas in clinical dentistry,autologous SHED was able to rege-nerate necrotic dental pulp after implantation into injured teeth,and micrografts enriched with autologous hDPSCs and collagen sponge were considered a treatment option for human intrabony defects.In contrast,hDPSCs did not add a significant regenerative effect when they were used for the treatment of post-extraction sockets.Large-scale clinical studies across diverse populations are still lacking to provide robust evidence on the safety and efficacy of hDPSCs as a new treatment option for various human diseases including dental-related problems.

Dental pulp stem cells stimulate neuronal differentiation of PC12 cells

Dental pulp stem cells(DPSCs) secrete neurotrophic factors which may play an important therapeutic role in neural development, maintenance and repair. To test this hypothesis, DPSCs-conditioned medium(DPSCs-CM) was collected from 72 hours serum-free DPSCs cultures. The impact of DPSCs-derived factors on PC12 survival, growth, migration and differentiation was investigated. PC12 cells were treated with nerve growth factor(NGF), DPSCs-CM or co-cultured with DPSCs using Transwell inserts for 8 days. The number of surviving cells with neurite outgrowths and the length of neurites were measured by image analysis. Immunocytochemical staining was used to evaluate the expression of neuronal markers NeuN, microtubule associated protein 2(MAP-2) and cytoskeletal marker βIII-tubulin. Gene expression levels of axonal growth-associated protein 43 and synaptic protein Synapsin-I, NeuN, MAP-2 and βIII-tubulin were analysed by quantitative polymerase chain reaction(qRT-PCR). DPSCs-CM was analysed for the neurotrophic factors(NGF, brain-derived neurotrophic factor [BDNF], neurotrophin-3, and glial cell-derived neurotrophic factor [GDNF]) by specific ELISAs. Specific neutralizing antibodies against the detected neurotrophic factors were used to study their exact role on PC12 neuronal survival and neurite outgrowth extension. DPSCs-CM significantly promoted cell survival and induced the neurite outgrowth confirmed by NeuN, MAP-2 and βIII-tubulin immunostaining. Furthermore, DPSCsCM was significantly more effective in stimulating PC12 neurite outgrowths than live DPSCs/PC12 co-cultures over the time studied. The morphology of induced PC12 cells in DPSCs-CM was similar to NGF positive controls;however, DPSCs-CM stimulation of cell survival was significantly higher than what was seen in NGF-treated cultures. The number of surviving PC12 cells treated with DPSCs-CM was markedly reduced by the addition of anti-GDNF, whilst PC12 neurite outgrowth was significantly attenuated by anti-NGF, anti-GDNF and anti-BDNF antibodies. These findings demonstrated that DPSCs were able to promote PC12 survival and differentiation. DPSCs-derived NGF, BDNF and GDNF were involved in the stimulatory action on neurite outgrowth, whereas GDNF also had a significant role in promoting PC12 survival. DPSCs-derived factors may be harnessed as a cell-free therapy for peripheral nerve repair. All experiments were conducted on dead animals that were not sacrificed for the purpose of the study. All the methods were carried out in accordance with Birmingham University guidelines and regulations and the ethical approval is not needed.

Early therapeutic effect of platelet-rich fibrin combined with allogeneic bone marrow-derived stem cells on rats’ critical-sized mandibular defects

BACKGROUND Critically sized bone defects represent a significant challenge to orthopaedic surgeons worldwide.These defects generally result from severe trauma or resection of a whole large tumour.Autologous bone grafts are the current gold standard for the reconstruction of such defects.However,due to increased patient morbidity and the need for a second operative site,other lines of treatment should be introduced.To find alternative unconventional therapies to manage such defects,bone tissue engineering using a combination of suitable bioactive factors,cells,and biocompatible scaffolds offers a promising new approach for bone regeneration.AIM To evaluate the healing capacity of platelet-rich fibrin(PRF)membranes seeded with allogeneic mesenchymal bone marrow-derived stem cells(BMSCs)on critically sized mandibular defects in a rat model.METHODS Sixty-three Sprague Dawley rats were subjected to bilateral bone defects of critical size in the mandibles created by a 5-mm diameter trephine bur.Rats were allocated to three equal groups of 21 rats each.Group I bone defects were irrigated with normal saline and designed as negative controls.Defects of group II were grafted with PRF membranes and served as positive controls,while defects of group III were grafted with PRF membranes seeded with allogeneic BMSCs.Seven rats from each group were killed at 1,2 and 4 wk.The mandibles were dissected and prepared for routine haematoxylin and eosin(HE)staining,Masson's trichrome staining and CD68 immunohistochemical staining.RESULTS Four weeks postoperatively,the percentage area of newly formed bone was significantly higher in group III(0.88±0.02)than in groups I(0.02±0.00)and II(0.60±0.02).The amount of granulation tissue formation was lower in group III(0.12±0.02)than in groups I(0.20±0.02)and II(0.40±0.02).The number of inflammatory cells was lower in group III(0.29±0.03)than in groups I(4.82±0.08)and II(3.09±0.07).CONCLUSION Bone regenerative quality of critically sized mandibular bone defects in rats was better promoted by PRF membranes seeded with BMSCs than with PRF membranes alone.

Isolation and characterisation of human gingival margin-derived STRO-1/MACS^+ and MACS^-cell populations

Recently,gingival margin-derived stem/progenitor cells isolated via STRO-1/magnetic activated cell sorting（MACS） showed remarkable periodontal regenerative potential in vivo.As a second-stage investigation,the present study＇s aim was to perform in vitro characterisation and comparison of the stem/progenitor cell characteristics of sorted STRO-1-positive（MACS~＋） and STRO-1-negative（MACS^-） cell populations from the human free gingival margin.Cells were isolated from the free gingiva using a minimally invasive technique and were magnetically sorted using anti-STRO-1 antibodies.Subsequently,the MACS~＋ and MACS^- cell fractions were characterized by flow cytometry for expression of CD14,CD34,CD45,CD73,CD90,CD105,CD146/MUC18 and STRO-1.Colony-forming unit（CFU） and multilineage differentiation potential were assayed for both cell fractions.Mineralisation marker expression was examined using real-time polymerase chain reaction（PCR）.MACS~＋ and MACS- cell fractions showed plastic adherence.MACS~＋ cells,in contrast to MACS- cells,showed all of the predefined mesenchymal stem/progenitor cell characteristics and a significantly higher number of CFUs（P〈0.01）.More than 95%of MACS~＋ cells expressed CD105,CD90 and CD73;lacked the haematopoietic markers CD45,CD34 and CD14,and expressed STRO-1 and CD146/MUC18.MACS- cells showed a different surface marker expression profile,with almost no expression of CD14 or STRO-1,and more than 95%of these cells expressed CD73,CD90 and CD146/MUC18,as well as the haematopoietic markers CD34 and CD45 and CD105.MACS~＋ cells could be differentiated along osteoblastic,adipocytic and chondroblastic lineages.In contrast,MACS- cells demonstrated slight osteogenic potential.Unstimulated MACS~＋ cells showed significantly higher expression of collagen I（P〈0.05） and collagen III（P〈0.01）,whereas MACS^- cells demonstrated higher expression of osteonectin（P〈0.05;MannWhitney）.The present study is the first to compare gingival MACS~＋ and MACS- cell populations demonstrating that MACS~＋ cells,in contrast to MACS- cells,harbour stem/progenitor cell characteristics.This study also validates the effectiveness of the STRO-l/MACS~＋technique for the isolation of gingival stem/progenitor cells.Human free gingival margin-derived STRO-1/MACS~＋ cells are a unique renewable source of multipotent stem/progenitor cells.

Surface roughness of zirconia for full-contour crowns after clinically simulated grinding and polishing

The aim of this study was to evaluate the effect of controlled intraoral grinding and polishing on the roughness of full-contour zirconia compared to classical veneered zirconia. Thirty bar-shaped zirconia specimens were fabricated and divided into two groups（n515）. Fifteen specimens（group 1） were glazed and 15 specimens（group 2） were veneered with feldspathic ceramic and then glazed. Prior to grinding,maximum roughness depth（Rmax） values were measured using a profilometer, 5 times per specimen. Simulated clinical grinding and polishing were performed on the specimens under water coolant for 15 s and 2 N pressure. For grinding, NTI diamonds burs with grain sizes of 20 mm, 10 mm, and 7.5 mm were used sequentially. The ground surfaces were polished using NTI kits with coarse, medium and fine polishers. After each step, Rmaxvalues were determined. Differences between groups were examined using one-way analysis of variance（ANOVA）. The roughness of group 1 was significantly lower than that of group 2. The roughness increased significantly after coarse grinding in both groups. The results after glazing were similar to those obtained after fine grinding for non-veneered zirconia. However, fine-ground veneered zirconia had significantly higher roughness than venerred, glazed zirconia. No significant difference was found between fine-polished and glazed zirconia, but after the fine polishing of veneered zirconia, the roughness was significantly higher than after glazing.It can be concluded that for full-contour zirconia, fewer defects and lower roughness values resulted after grinding and polishing compared to veneered zirconia. After polishing zirconia, lower roughness values were achieved compared to glazing; more interesting was that the grinding of glazed zirconia using the NTI three-step system could deliver smooth surfaces comparable to untreated glazed zirconia surfaces.

Bisphosphonates Zoledronate and Alendronate for the Management of Postmenopausal Osteoporosis

Bisphosphonates are among the most frequently used antiresorptive drugs for the management of postmenopausal osteoporosis. We review here two of the commonly used bisphosphonates zoledronate and alendronate.

Synthesis, Reactions and Characterization of 1,1’-(1,4-Phenylenebis(3-amino-6-methyl-1H-pyrazolo[3,4-b]pyridine-4,5-diyl))bis(ethan-1-one)

Reaction of 4,4’-(1,4-phenylene)bis(5-acetyl-6-methyl-2-thioxo-1,2-dihydropyridine-3-carbonitrile) (1) with methyl iodide afforded the 4,4’-(1,4-phenylene)bis(5-acetyl-6-methyl-2-(methylthio)nicotinonitrile) (2). The reaction of 2 with hydrazine hydrate followed by diazotization reaction af-forded the 1,1’-(1,4-phenylenebis(3-amino-6-methyl-1H-pyrazolo[3,4-b]pyridine-4,5-diyl))bis(e-than-1-one) (3) and 1,1’-(1,4-phenylenebis(3-(chlorodiazenyl)-6-methyl-1H-pyrazolo[3,4-b]-pyridine-4,5-diyl))bis(ethan-1-one) (4) respectively. On the other hand, reaction of 4 with malononitrile, 2-cyanoethanethioamide, ethyl acetoacetate, acetyl acetone, ethyl benzoylacetate, diethylmalonate, ethyl cyanoacetate and phenacylbromide aiming to build up pyrazolotriazine or pyrazole ring on the ring system of 4. Structures of all newly synthesized heterocyclic compounds in the present study were confirmed by considering the data of IR, 1H NMR, mass spectra as well as that of elemental analyses.

Spectral, Thermal and Antibacterial Studies for Bivalent Metal Complexes of Oxalyl, Malonyl and Succinyl-bis-4-phenylthiosemicarbazide Ligands

The thermogravimetry (TG) and derivative thermogravimetry (DTG) have been used to study the thermal decomposition of some oxalyl (H4OxTSC), malonyl (H4MaTSC) and succinyl-bis-4-phenyl- thiosemicarbazide (H4SuTSC) ligands and their metal complexes using Horowitz-Metzger (HM) and Coats-Redfern methods. The kinetic thermodynamic parameters such as: E*, ΔH*, ΔS*and ΔG* are calculated from the DTG curves. The isolated complexes have the general composition [M2(L) (H2O)6], where M=Cu(II), Zn(II), L=MaTSC and M=Co(II), Cu(II) or Sn(II) and L=Su TSC and [M2(L) (H2O)n]·nH2O where M=Cu(II), Co(II) or Sn(II), L=OxTS or Ma TSC. The tested compounds show a good activity against four strains of bacteria Gram negative Escherichia coli, Pseudomonas aeruginosa species and gram-positive Bacillus cereus and Staphylococcus aureus.

Clinical correlates of common corneal neovascular diseases: a literature review

A large subset of corneal pathologies involves the formation of new vessels(neovascularization), leading to compromised visual acuity. This article aims to review the clinical causes and presentations of corneal neovascularization(CNV) by examining the mechanisms behind common CNV-related corneal pathologies, with a particular focus on herpes simplex stromal keratitis,contact lenses-induced keratitis and CNV secondary to keratoplasty. Moreover, we reviewed CNV in the context of different types of corneal transplantation and keratoprosthesis, and summarized the most relevant treatment available so far.

Molecular underpinnings of corneal angiogenesis:advances over the past decade

The cornea is maintained in an avascular state by maintaining an environment whereby anti-angiogenic factors take the upper hand over factors promoting angiogenesis. Many of the common pathologies affecting the cornea involve the disruption of such equilibrium and the shift towards new vessel formation, leading to corneal opacity and eventually-vision loss. Therefore it is of paramount importance that the molecular underpinnings of corneal neovascularization（CNV） be clearly understood, in order to develop better targeted treatments. This article is a review of the literature on the recent discoveries regarding pro-angiogenic factors of the cornea（such as vascular endothelial growth factors,fibroblast growth factor and matrix metalloproteinases）and anti-angiogenic factors of the cornea（such as endostatins and neostatins）. Further, we review the molecular underpinnings of lymphangiogenesis, a process now known to be almost separate from（yet related to） hemangiogenesis.

Cone-beam computed tomography analysis of curved root canals after mechanical preparation with three nickel-titanium rotary instruments

Cone beam computed tomography is a 3-dimensional high resolution imaging method. The purpose of this study was to compare the effects of 3 different NiTi rotary instruments used to prepare curved root canals on the final shape of the curved canals and total amount of root canal transportation by using cone-beam computed tomography. A total of 81 mesial root canals from 42 extracted human mandibular molars, with a curvature ranging from 15 to 45 degrees, were selected. Canals were randomly divided into 3 groups of 27 each. After preparation with Protaper, Revo-S and Hero Shaper, the amount of transportation and centering ability that occurred were assessed by using cone beam computed tomography. Utilizing preand post-instrumentation radiographs, straightening of the canal curvatures was determined with a computer image analysis program. Canals were metrically assessed for changes （surface area, changes in curvature and transportation） during canal preparation by using software SimPlant; instrument failures were also recorded. Mean total widths and outer and inner width measurements were determined on each central canal path and differences were statistically analyzed. The results showed that all instruments maintained the original canal curvature well with no significant differences between the different files （P=0.226）. During preparation there was failure of only one file （the protaper group）. In conclusion, under the conditions of this study, all instruments maintained the original canal curvature well and were safe to use. Areas of uninstrumented root canal wall were left in all regions using the various systems.

Therapeutic Potential of Bone Marrow Derived Mesenchymal Stem Cells in Modulating Astroglyosis of Surgical Induced Experimental Spinal Cord Injury

Background: Spinal cord injury (SCI) unsuccessful regeneration was due to glial scar development. It was a major obstacle to axonal restoration. Safe therapeutic intervention by the use of bone marrow derived stem cells (BMMSCs) transplantation applied in the present study could reduce spinal disability. Material and methods: Forty male albino rats were divided into four groups: GI: negative control (n = 10 rats);GII: positive control after SCI (n = 10 rats);GIII: SCI + BM - MSCs intravenous injected and GIV: SCI + BM - MSCs intra lesion injected (n = 10 rats in each group). The samples were taken from spinal cord tissues around the region of injury and were subjected to histological, immunohistochemical assessment. RNA extraction and real time PCR for detection of nerve regeneration and astrocyte response to the injury were also performed. Results: Clinical improvement occurred by the enhancement in the Basso, Beattie and Bresnahan (BBB) score after SCI. Histological examinations showed positive regenerative responses in GIV compared to GIII. Conclusion: BM-MSCs transplantation has a promising role in enhancing the microenvironment for nerve regeneration through stumbling the glial scaring formation and inflammatory response after chronic spinal cord injury especially by using intra-lesion route injection.

Accuracy of Orthodontic 3D Printed Retainers versus Thermoformed Retainers

Background: The integration of the current technology of CBCT and 3D CAD/CAM technology has great potential in the field of orthodontics, which is not yet fully investigated. The purpose of this article is to evaluate the accuracy of 3D printed retainers in comparison to vacuum formed retainers. Methods: Alginate impressions were taken for ten patients who have a CBCT scan. A 3D printed retainer and vacuum formed retainer were fabricated. Linear measure-ments were measured by two assessors using digital caliper. Every measure-ment on the 3D printed retainer was compared to the corresponding measure-ment on the thermoformed retainer. The linear measurements were Inter-canine width, Inter-premolar width (first and second premolars), Inter-molar width, Canine-midline length (both sides) and Canine-molar length (both sides). Intra-observer, and inter-observer reliability measurements were done. Results: Results showed excellent intra-observer reliability for the thermoformed retainer and the 3D printed retainer. Inter-observer measurements showed strong agreement between the measurements of the two assessors, for both retainers. The comparison of the thermoformed retainer to the 3D printed retainer showed high statistical agreement, except for the canine-molar on the right side, but with no clinical significance, p value of 0.038 and mean difference 0.19. Conclusions: The new method for fabricating a 3D printed retainer is accurate and reliable in comparison to the vacuum formed retainer (conventional method). CBCT proved to be efficient for fabrication of a custom made appliances.

Inter-Occlusal Separation in CBCT Imaging: Rationale and Method

A major advantage of CBCT is the ability to allow single-step data acquisition that computes all our diagnostic information and substitutes several conventional procedures of record taking. Yet, there are several protocols for CBCT imaging as regards the interocclusal separation, each with a drastic shortcoming. The authors herein propose a protocol that offers acceptable inter-occlusal separation during CBCT imaging using a radiolucent splint that guarantees reproducibility, undisrupted facial form, centric condylar position concurrently with feasibility for occlusal analysis, separation of the maxillary and mandibular teeth and hence digital simulation of the orthodontic treatment.

Adaptive Dynamic Dipper Throated Optimization for Feature Selection in Medical Data

The rapid population growth results in a crucial problem in the early detection of diseases inmedical research.Among all the cancers unveiled,breast cancer is considered the second most severe cancer.Consequently,an exponential rising in death cases incurred by breast cancer is expected due to the rapid population growth and the lack of resources required for performing medical diagnoses.Utilizing recent advances in machine learning could help medical staff in diagnosing diseases as they offer effective,reliable,and rapid responses,which could help in decreasing the death risk.In this paper,we propose a new algorithm for feature selection based on a hybrid between powerful and recently emerged optimizers,namely,guided whale and dipper throated optimizers.The proposed algorithm is evaluated using four publicly available breast cancer datasets.The evaluation results show the effectiveness of the proposed approach from the accuracy and speed perspectives.To prove the superiority of the proposed algorithm,a set of competing feature selection algorithms were incorporated into the conducted experiments.In addition,a group of statistical analysis experiments was conducted to emphasize the superiority and stability of the proposed algorithm.The best-achieved breast cancer prediction average accuracy based on the proposed algorithm is 99.453%.This result is achieved in an average time of 3.6725 s,the best result among all the competing approaches utilized in the experiments.

Anti-proliferative and apoptotic efficacy of diallyl disulfide onEhrlich ascites carcinoma

Aim:This study was conducted to assess the in vivo and in vitro anti-tumor effects of diallyl disulfi de(DADS)against Ehrlich ascites carcinoma(EAC)and to suggest its probable mechanism of action.Methods:EAC was induced in female mice by intraperitoneal injection of EAC-cells from stock mice.EAC-bearing mice were orally treated with 100 mg/kg body weight for 2 weeks beginning from the 1st day of EAC intraperitoneal transplantation.Cytotoxicity effects of DADS against EAC-cells in vitro were investigated at different concentrations(0,6.25,12.5,25,50,and 100μg/mL)of DADS using trypan blue exclusion assay.Results:Data from this study exhibited a signifi cant decrease in EAC-aliquot volume as well as total and alive EAC-cell number and a marked increase in dead EAC-cell number and percent in EAC-bearing mice treated with DADS as compared with EAC-bearing control.These changes were consistent with increased number of cells which exhibited phenotypic apoptotic signs marked by a decrease in the expression of anti-apoptotic protein Bcl-2,an increase of pro-apoptotic and cell cycle arrest mediator p53 and an elevation of DNA fragmenting indicator terminal deoxynucleotidyl transferase in EAC-bearing mice treated with DADS.In addition,the tumor marker sialic acid level was markedly decreased in plasma and Ehrlich ascites in EAC-bearing mice treated with DADS.In vitro,DADS also produced anti-proliferative and anti-tumor cytotoxic potentials against EAC.Conclusion:DADS may have anti-cancer effects which may be mediated via modulation of apoptosis and cell cycle arrest.