Radiographic & histopathological analysis in calvarias bone regeneration process by platelet-rich plasma, platelet-rich plasma–gel And auto bone chips in rat

A functional treatment for skeletal damages in orthopedic and oral maxillofacial surgeries is required. Platelet growth factors such as Platelet Derived Growth Factor (PDGF), Bone Morphogenic Factor (BMP), Transferring Growth Factor-β (TGF-β) and Insulin-like Growth Factor-1 (IGF-1) proceed wound healing and bone regeneration. In the present study we focused on the effect of platelet rich plasma (PRP), platelet rich plasma gel (PRP-Gel) and auto bone chips on this process. 30 male, 22 weeks old, Sprague-Dawley rats weighing 525 g were used. They were divided in three groups consisting of PRP (treated by Platelet-Rich Plasma), PRP-Gel (treated by it), Bone chips and Control (two cavities created in each animal in this group). After 16 weeks they were histologically investigated while in the periods of 40, 60, 90and 120 days, the radiography had been done. The radiographic analysis showed complete treatment in all groups; however, by the histo-pathological investigations by auto bone chips complete and PRP-Gel partial healing has been observed. By histo-morphometric surveys (100±25) % in bone chips and (50±25) % in PRP-Gel groups bone bridging were observed, whereas in PRP it was not noticeable. The Present study suggests that neither PRP, nor PRP-Gel could be as beneficial as bone chips. Statistically, in PRP-Gel group, due to the existence of fibrin and thrombin, solid bone bridging at the treated site is indicated. According to the previous studies, in which the key role of both inhibitory and stimulatory signals in controlling the bone regeneration were proven, we suggest that auto bone chips could completely enhance healing due to signals among blood factors, environmental tissues and skeletal particles.

Evaluation of Pluripotency Gene Expression in Mouse Embryonic Stem Cell Cultured on the Human Feeder Layer

Embryonic stem (ES) cells are derived from the pluripotent inner cell mass (ICN) cells of blastocysts with the potential to maintain an undifferentiated state indefinitely. The derivation process involves plating of the blastocysts on mouse embryonic fibroblast (MEF) and expansion of the outgrowth in to established ES cell line. ES cell are capable of unlimited self-renewal by symmetric division and differentiated cells to all primitive embryonic germ layers. The capacity of ES cells to differentiate in to almost all the cell types of human body highlights their potential to play a promising role in cell replacement therapies for treatment of human diseases. In this study, MEFs have been replaced with human mesenchymal stem cells (hMSCs). C4 mES cell (mouse embryonic stem cell line) colonies are cultured on inactivated hMSCs amplified ≥ 600-folds during the 30 days of continuous culture. The longest continuous expansion of C4 mES cells on hMSC was 30 passages. In this study the gene expression for Oct-4, Nanog, Rex1, Brachyury, LIF, LIFR, TERT, B2M, Stat3, Sox2, Fgf4 in mES cells using reverse transcriptase polymerase chain reaction (RT-PCR) and in which genes expression for Stat3, Sox2, Fgf4 genes was negative whilst the  gene expansion for Oct-4, Nanog, Rex1, Brachyury, LIF, LIFR, TERT, B2M  genes was  positive. There was also a karyotype analysis for ES which showed normal result. The immunocytochemical analysis of Oct4 transcriptional factor for ES cells was made which showed positive result for this factor. These genes may be novel candidates to play critical roles in the regulation of ES Cell pluripotency and self-renewal

Critical-Sized Bone Defects Regeneration Using a Bone-Inspired 3D Bilayer Collagen Membrane in Combination with Leukocyte and Platelet-Rich Fibrin Membrane (L-PRF): An \u3cem\u3eIn Vivo\u3c/em\u3e Study

Objectives We aim to develop a 3D-bilayer collagen (COL) membrane reinforced with nano beta-tricalcium-phosphate (nβ-TCP) particles and to evaluate its bone regeneration in combination with leukocyte-platelet-rich fibrin (L-PRF) in vivo. Background data L-PRF has exhibited promising results as a cell carrier in bone regeneration in a number of clinical studies, however there are some studies that did not confirm the positive results of L-PRF application. Methods Mechanical & physiochemical characteristics of the COL/nβ-TCP membrane (1/2 & 1/4) were tested. Proliferation and osteogenic differentiation of seeded cells on bilayer collagen/nβ-TCP thick membrane was examined. Then, critical-sized calvarial defects in 8 white New Zealand rabbits were filled with either Col, Col/nβ-TCP, Col/nβ-TCP combined with L-PRF membrane, or left empty. New bone formation (NBF) was measured histomorphometrically 4 & 8 weeks postoperatively. Results Compressive modulus increases while porosity decreases with higher β-TCP concentrations. Mechanical properties improve, with 89 % porosity (pore size ∼100 μm) in the bilayer-collagen/nβ-TCP membrane. The bilayer design also enhances the proliferation and ALP activity. In vivo study shows no significant difference among test groups at 4 weeks, but Col/nβ-TCP + L-PRF demonstrates more NBF compared to others (P \u3c 0.05) after 8 weeks. Conclusion The bilayer-collagen/nβ-TCP thick membrane shows promising physiochemical in vitro results and significant NBF, as ¾ of the defect is filled with lamellar bone when combined with L-PRF membrane

Types of neural guides and using nanotechnology for peripheral nerve reconstruction

Peripheral nerve injuries can lead to lifetime loss of function and permanent disfigurement. Different methods, such as conventional allograft procedures and use of biologic tubes present problems when used for damaged peripheral nerve reconstruction. Designed scaffolds comprised of natural and synthetic materials are now widely used in the reconstruction of damaged tissues. Utilization of absorbable and nonabsorbable synthetic and natural polymers with unique characteristics can be an appropriate solution to repair damaged nerve tissues. Polymeric nanofibrous scaffolds with properties similar to neural structures can be more effective in the reconstruction process. Better cell adhesion and migration, more guiding of axons, and structural features, such as porosity, provide a clearer role for nanofibers in the restoration of neural tissues. In this paper, basic concepts of peripheral nerve injury, types of artificial and natural guides, and methods to improve the performance of tubes, such as orientation, nanotechnology applications for nerve reconstruction, fibers and nanofibers, electrospinning methods, and their application in peripheral nerve reconstruction are reviewed

Evaluation of antitumor activity of a TGF-beta receptor I inhibitor (SD-208) on human colon adenocarcinoma.

BACKGROUND: Transforming growth factor-β (TGF-β) pathway is involved in primary tumor progression and in promoting metastasis in a considerable proportion of human cancers such as colorectal cancer (CRC). Therefore, blockage of TGF-β pathway signaling via an inhibitor could be a valuable tool in CRC treatment. METHODS: To evaluate the efficacy of systemic targeting of the TGF-β pathway for therapeutic effects on CRC, we investigated the effects of a TGβRI (TGF-β receptor 1) or TβRI kinase inhibitor, SD-208, on SW-48, colon adenocarcinoma cells. In this work, in vitro cell proliferation was studied by methyl thiazolyl tetrazolium (MTT) and bromo-2'-deoxyuridine (BrdU) assays. Also, the histopathological and immunohistochemical evaluations were conducted by hematoxylin and eosin, and Ki-67 and CD34 markers were stained, respectively. RESULTS: Our results showed no significant reduction in cell proliferation and vessel formation (170 ± 70 and 165 ± 70, P > 0.05) in treated SW-48 cells with SD-208 compared to controls. CONCLUSION: Our data suggested that SD-208 could not significantly reduce tumor growth and angiogenesis in human colorectal cancer model at least using SW-48 cells

Assessment of Surface Markers Derived from Human Periodontal Ligament Stem Cells: An In Vitro Study

Objectives: Periodontal tissue regeneration for treatment of periodontal disease has not yet been mastered in tissue engineering. Stem cells, scaffold, and growth factors are the three main basic components of tissue engineering. Periodontal ligament (PDL) contains stem cells; however, the number, potency and features of these cells have not yet been understood. This study aimed to isolate and characterize the properties of PDL stem cells. Materials and Methods: In this experimental study, samples were isolated from the PDL of extracted teeth of five patients and then stained immunohistochemically for detection of cell surface markers. Cells were then examined by immuno-flow cytometry for mesenchymal markers as well as for osteogenic and adipogenic differentiation. Results: The isolated cell population had fibroblast-like morphology and flow cytometry revealed that the mesenchymal surface markers were (means): CD90 (84.55), CD31 (39.97), CD166 (33.77), CD105 (31.19), CD45 (32/44), CD44 (462.11), CD34 (227.33), CD38 (86.94), CD13 (34.52) and CD73 (50.39). The PDL stem cells also differentiated into osteoblasts and adipocytes in osteogenic and adipogenic media, respectively. Conclusions: PDL stem cells expressed mesenchymal stem cell (MSC) markers and differentiated into osteoblasts and adipocytes in osteogenic and adipogenic media, respectively.

Human amniotic membrane, best healing accelerator, and the choice of bone induction for vestibuloplasty technique (an animal study)

Mohammad H Samandari1, Shahriar Adibi2, Ahad Khoshzaban3, Sara Aghazadeh5, Parviz Dihimi4, Siamak S Torbaghan6, Saeed H Keshel5, Zohreh Shahabi71Department of Oral and Maxillofacial Surgery, Dentistry Faculty, 2Dental Research of Torabinejad Research Centre, 3Iranian Tissue Bank Research and Preparation Centre, Imam Khomeini Hospital Complex, 4Department of Oral and Maxillofacial Pathology, Dentistry Faculty, Isfahan University of Medical Sciences, Isfahan, Iran; 5Stem Cells Preparation Unit, Eye Research Center, Farabi Hospital, 6Department of Pathology, Imam Khomeini Medical Centre, 7BMT Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, IranObjective: To investigate the effects of amniotic membrane (AM) in bone induction and wound healing after vestibuloplasty surgery on animal samples while receptacle proteins such as growth factors were considered as accelerators for wound healing and bone induction after these operations.Material and methods: Ten adult dogs (5 females, 5 males; race, Iranian mixed; weight, 44 pounds) were included, which underwent surgery for transplantation on mandible and maxillary. AM was used for promoting bone induction and healing.Results: The tissue samples were obtained after 2, 8, and 12 weeks for histology survey. No significant differences were observed between male and female or left and right jaws. AM decreased fibrinoleukocytic exudates and inflammation in the experimental group, had significant effects on bone formation, considerably improves wound healing, and gives rise to bone induction (P < 0.0001).Conclusions: Our study findings indicate that the AM is a suitable cover for different injuries and acellular AM has the potential for rapid improvement and bone induction. The AM contains collagen, laminin, and fibronectin, which provide an appropriate substrate for bone induction. This substrate promoted bone induction and might contribute to induction of the progenitor cells and/or stem cells in the area where surgery had been undertaken and is also differentiated into bone. In comparison with the control group, the difference was significant and meaningful (P < 0.0001).Keywords: inflammation, bone induction, fibrinoleukocytic exudates&nbsp

Expression of Odontogenic Genes in Human Bone Marrow Mesenchymal Stem Cells

Objective: Tooth loss is a common problem and since current tooth replacement methods cannot counter balance with biological tooth structures, regenerating natural tooth structures has become an ideal goal. A challenging problem in tooth regeneration is to find a proper clinically feasible cell to seed.This study was designed to investigate the odontogenic potential of human bone marrow mesenchymal stem cells (HBMSCs) for seeding in tooth regeneration.Materials and Methods: In this experimental study, three pregnant Sprague Dawley (SD) rats were used at the eleventh embryonic day and rat fetuses were removed surgically using semilunar flap under general anesthesia. The primary mandible was cut using a stereomicroscope. The epithelial and mesenchymal components were separated and the dissected oral epithelium was cultured for 3 days. We used flow cytometry analysis to confirm presence of mesenchymal stem cells and not hematopoietic cells and to demonstrate the presence of oral epithelium. Bone marrow mesenchymal stem cells (BMSCs) and cultured oral epithelium were then co-cultured for 14 days. BMSCs cultured alone were used as controls. Expression of two odontogenic genes Pax9 and DMP1 was assessed using quantitative reverse transcription- polymerase chain reaction (RT-PCR).Results: Expression of two odontogenic genes, Pax9 and DMP1, were detected in BMSCs co-cultured with oral epithelium but not in the control group.Conclusion: Expression of Pax9 and DMP1 by human BMSCs in the proximity of odontogenic epithelium indicates odontogenic potential of these cells

Multidrug resistance protein 2 genetic polymorphism and colorectal cancer recurrence in patients receiving adjuvant FOLFOX-4 chemotherapy

Multidrug resistance protein 2 (MRP2), encoded by the ATP-binding cassette C2 (ABCC2) gene, is an efflux pump located on the apical membrane of many polarized cells, which transports conjugate compounds by an ATP-dependent mechanism. The correlation of G1249A ABCC2 polymorphism with the development of colorectal cancer (CRC) and poor prognosis was evaluated in patients who were treated with fluorouracil/leucovorin (FL) plus oxaliplatin (FOLFOX-4). A total of 50 paraffin embedded tissue samples collected from CRC patients were analyzed to identify the polymorphism. Patients were in stage II/III and received postoperative FOLFOX-4 chemotherapy. As a control group, an equal number of unrelated healthy subjects were enrolled in the study. The polymorphism was genotyped by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, and results were compared with clinicopathological markers, early relapse and survival rates. During the 12 months of follow-up, local and distant recurrences were observed in 15 (30%) patients. No significant difference in the distribution of wild-type and polymorphic genotypes was observed between the patient and control groups and between the patients who experienced recurrence within 1 year and those who did not (all P>0.05). In conclusion, the G1249A polymorphism is not associated with CRC risk and early recurrence. However, significant correlation was observed between G1249A polymorphism and the overall survival and disease-free survival of the patients

Alginate Microcapsules as Nutrient Suppliers : An In-vitro Study

Objective Alginate, known as a group of anionic polysaccharides extracted from seaweeds, has attracted the attention of researchers because of its biocompatibility and degradability properties. Alginate has shown beneficial effects on wound healing as it has similar function as extracellular matrix. Alginate microcapsules (AM) that are used in tissue engineering as well as Dulbecco’s modified Eagle’s medium (DMEM) contain nutrients required for cell viability. The purpose of this research was introducing AM in medium and nutrient reagent cells and making a comparison with control group cells that have been normally cultured in long term. Materials and Methods In this experimental study, AM were shaped in distilled water, it was dropped at 5 mL/hours through a flat 25G5/8 sterile needle into a crosslinking bath containing 0.1 M calcium chloride to produce calcium alginate microspheres. Then, the size of microcapsules (300-350 µm) were confirmed by Scanning Electron Microscopy (SEM) images after the filtration for selection of the best size. Next, DMEM was injected into AM. Afterward, adipose- derived mesenchymal stem cells (ADSCs) and Ringer’s serum were added. Then, MTT and DAPI assays were used for cell viability and nucleus staining, respectively. Also, morphology of microcapsules was determined under invert microscopy. Results Evaluation of the cells performed for spatial media/microcapsules at the volume of 40 µl, showed ADSCs after 1-day cell culture. Also, MTT assay results showed a significant difference in the viability of sustained-release media injected to microcapsules (P<0.05). DAPI staining revealed living cells on the microcapsules after 1 to 7-day cell culture. Conclusion According to the results, AM had a positive effect on cell viability in scaffolds and tissue engineering and provide nutrients needed in cell therapy