Genotoxicity and cytotoxicity of orthodontic bonding adhesives: a review

Orthodontic bonding adhesive is one of the integral parts of orthodontic treatment. By means of orthodontic bonding adhesives, different components of fixed orthodontic appliances are attached to the tooth surface. Manufacturers have been introducing various bonding adhesives as there is an increasing demand for orthodontic treatment presently. Focus has been made more on the physical properties of these bonding adhesives rather than their biocompatibility. As orthodontic treatment is a long-time process, the bonding adhesives also remain in close proximity with intra-oral tissues. Therefore, biocompatibility of these adhesives in respect to their genotoxicity and cytotoxicity should be a concern while clinically implicating them. The aim of this review was to provide information about the genotoxicity and cytotoxicity effects of various orthodontic bonding adhesives. An electronic search was conducted across Cochrane, Medline, Web of Science databases, and Google Scholar for literature analysis on the mentioned topic. The studies were reviewed and compared. This article summarizes the results of research studies that have been done to see the genotoxicity and cytotoxicity of orthodontic bonding adhesives. Most research studies summarized in this review article concluded that orthodontic bonding adhesives show some extent of either genotoxicity or cytotoxicity or both. There is still a lack of scientific literature on long-term in vivo studies on the toxic effects of these adhesives. It is advisable to employ several genetic assays and standardized methods for genotoxic evaluation of bonding adhesives through longtime clinical in vivo studies

Potential applications of horseshoe crab in biomedical research

Horseshoe crab is one of the oldest existing living fossils comprising four main species today. Of these, Limulus Polyphemus is found in North America and the other three species, Tachypleus tridentatus, Tachypleus gigas and Carcinoscorpius rotundicauda are found in Southeast Asia. Horseshoe crabs play important roles in the regulation of the coastal ecology communities whereby the eggs serve as the main diet of shorebird species during the migrating season. Horseshoe crab is also seen as a versatile organism, useful in the biomedicine field particularly, as its blue blood has been widely integrated to be used for endotoxin tester in vaccines, drugs and injectables. Researchers have explored a material called perivitelline fluid (PVF) from the egg of a fertilized horseshoe crab which is rich in important proteins and amino acids that are crucial for embryogenesis. Previous studies have shown that PVF has the ability to enhance cell growth and differentiation as well as in promoting generation of certain organs. Testing of PVF on many types of cells has shown positive results and hence, it is suggested that PVF could be used as a supplement to support cell growth in future. Highlighting the horseshoe crab as a living fossil, this review brings out the relevance of the blue blood and PVF of the horseshoe crab as sources benefitting molecular research

Keloid Scarring: Understanding the Genetic Basis, Advances, and Prospects

Keloid disease is a fibroproliferative dermal tumor with an unknown etiology that occurs after a skin injury in genetically susceptible individuals. Increased familial aggregation, a higher prevalence in certain races, parallelism in identical twins, and alteration in gene expression all favor a remarkable genetic contribution to keloid pathology. It seems that the environment triggers the disease in genetically susceptible individuals. Several genes have been implicated in the etiology of keloid disease, but no single gene mutation has thus far been found to be responsible. Therefore, a combination of methods such as association, gene-gene interaction, epigenetics, linkage, gene expression, and protein analysis should be applied to determine keloid etiology

EVALUATION OF ROYAL JELLY AS AN ALTERNATIVE TO FETAL BOVINE SERUM IN CELL CULTURE USING CELL PROLIFERATION ASSAYS AND LIVE CELL IMAGING

Background: Royal jelly is a nutritious substance produced by the young nurse bees and contains significant amounts of proteins which are important for cell growth and proliferation. The aim of this study was to evaluate the effect of royal jelly as an alternative to fetal bovine serum (FBS) in cell culture using cell proliferation assays and live cell imaging. Materials and Methods: MRC-5 cells were treated with various concentrations of royal jelly extract in MTT assay. The control groups were comprised of Alpha-Minimal Essential Medium (α-MEM) alone and α-MEM with 10% FBS. Subsequently, the cell proliferation was studied for 10 days using Alamar Blue assay and live cell imaging from 48 to 72 h. The population doubling time (PDT) was determined using trypan blue assay after live cell imaging. Results: In MTT assay, 0.156 and 0.078 mg/ml of royal jelly produced higher cell viability compared to positive control group but were not significantly different (P > 0.05). In the Alamar Blue assay, 0.156 and 0.078 mg/ml of royal jelly produced greater percentage of reduction at day 3 even though no significant difference was found (P > 0.05). Based on live cell imaging, the PDT for positive, negative, 0.156 and 0.078 mg/ml of royal jelly groups were 29.09, 62.50, 41.67 and 41.67 h respectively. No significant difference was found in the PDT between all the groups (P > 0.05). Conclusion: Royal jelly does not exhibit similar ability like FBS to facilitate cell growth under the present test conditions

Growth factor cocktail to facilitate epithelial differentiation of exfoliated deciduous teeth stem cells

Epithelial cells are important in the regeneration of oral mucosal tissue. The cell source is commonly derived from tissue biopsy, which is obtained through surgery. Stem cells from human exfoliated deciduous teeth (SHED) were demonstrated to differentiate into multiple cell types. As it can be readily available from exfoliated deciduous teeth, it can be induced and become a potential source of epithelial cell for oral tissue study. This study aims to examine a mixture of growth factors in the differentiation of epithelial-like cells obtained from human exfoliated deciduous teeth (SHED) stem cells. This growth factor cocktail constitutes hepatocyte growth factor (HGF), keratinocyte growth factor (KGF), insulin-like growth factor 2 (IGF-II), and epidermal growth factor (EGF). After introducing the cocktail, the treated SHED were assessed for epithelial characteristics and markers using cell proliferation test, morphological transformation, protein and gene expression by immunofluorescence staining and cytometry assessment, respectively. The proliferation rate was analysed statistically using Analysis of Variance (ANOVA) with Repeated Measures (p<0.05). SHED cells demonstrated morphological changes on the 7th day after using the cocktail. These transformations are in alignment with the identification of genes associated with epithelial cells and positive stain outcomes for pan-cytokeratin, E-cadherin, and p63. The cell proliferation test indicated that proliferation of cells and growth factor introduction were significantly correlated. The growth factor cocktail used for this research facilitated SHED differentiation for epithelial-like cells. The outcomes validate the production of epithelial cells using SHED; tissue production studies focus on these aspects immensely

Effect of FGF-2 and PDGF-BB on a co-culture of human gingival fibroblasts and umbilical vein endothelial cells

Gingival recession can be treated by root coverage procedure with tissue graft. The ideal gingiva graft should mimic the properties of the native gingiva. Gingival fibroblasts are main cells that reside in human gingiva, while the endothelial cells are the basis for blood vessel formation. The co-culture of these cells, will help in better understanding of gingival tissue regeneration. This study was aimed to determine the effects of fibroblast growth factor-2 (FGF-2) and plateletderived growth factor-BB (PDGF-BB) on a co-culture of human gingival fibroblasts (HGFs) and human umbilical vein endothelial cells (HUVECs). In this in vitro experimental study, the medium for the establishment of monolayer and coculture of these cells were first optimised. Then, the optimal concentrations of these growth factors were determined by assessing the cell viability using MTT assay. Next, to study the stimulatory effect of these growth factors, both HGF and HUVECs were co-cultured and gene expression analysis for fibroblast and angiogenic biomarkers was assessed using Real-Time RT-PCR. Cell viability assay showed that the effect of FGF-2 on HGF was dose-dependent and was optimum at a concentration of 5 ng mL-1, while that of PDGF-BB on HUVEC was optimum at a concentration of 20 ng mL-1. The stimulatory effect of FGF-2 and PDGF-BB was further supported by the Real-Time PCR results which showed that there is a significant expression of VIM, COL1A1, FN, CD31, VE-Cadherin, and vWF in the treatment group of both cells after three days of co-culture experiment, compared to control group. This study indicates a possible synergistic effect of FGF-2 and PDGF-BB growth factors in a co-culture of HGF and HUVEC leading to proangiogenic activity

Identification and Characterization of Intraoral and Dermal Fibroblasts Revisited

Abstract: Background: Fibroblasts are the common cells used in clinical regenerative medicine and dentistry. These cells are known to appear heterogeneous in vivo. Previous studies have only investigated the biological properties of these cell subpopulations in vitro. Despite sharing similarity in their spindle-shaped appearance, previous literatures revealed that they play distinguished functional and biological activities in the body. Objective: This paper highlights the similarities and differences among these cell subpopulations, particularly between intraoral fibroblasts (human periodontal ligament, gingival and oral mucosa fibroblasts) and dermal fibroblasts based on several factors including their morphology, growth and proliferation rate. Results: It could be suggested that each subpopulation of fibroblasts demonstrate different positionspecified gene signatures and responses towards extracellular signals. These dissimilarities are crucial to be taken into consideration to employ specific methodologies in stimulating these cells in vivo. Conclusion: A comparison of the characteristics of these cell subpopulations is desired for identifying appropriate cellular applications. Keywords: Dermal fibroblast, differences, gingival fibroblast, oral mucosa fibroblast, periodontal ligament fibroblast, similaritie

Malaysian herbs in contraception : public perception

Medicinal plants have been used in Malaysia for a long time ago. These plants have been marketed as herbal product and used in the traditional healthcare system because of its positive therapeutic effects. This paper discusses particularly several types of Malaysian herbs that are traditionally used for contraception and scientific studies related to its pharmaceutical properties showing its use among the public for its anti-fertility effects. Even though several methods of contraception have been promoted for family planning, yet, the perception of the public on the usage of synthetic steroidal contraceptives due to its serious adverse effects has made them focus on indigenous plants. Contraceptives drug-containing oestrogen and progesterone have proven to be effective and popular, However, the side effects of these drugs have sparked the idea of scientists to develop newer molecules from medicinal plants. Therefore, it is necessary to investigate in-depth qualitative research on conceptions and concerns about traditional contraceptive methods using herbal ingredients among Malaysians

Expression analysis of notch signaling pathway molecules in SHED cultured in keratinocyte growth medium

Aim: To detect the expression of molecules associated with Notch signaling pathway in stem cells from human exfoliated deciduous teeth (SHED) cultured in specific differentiation medium, namely, keratinocyte growth medium (KGM). Methods: RNA was extracted from SHED harvested on day 1, 3 and 7. RNA was reverse-transcribed to obtain the cDNA and then proceeded with PCR using specific primers for the Notch signaling pathway molecules (Notch1, Jagged-1, Jagged-2 and, Hes1) as well as stem cell marker (Nanog). PCR products were electrophoresed on a 2% agarose gel and stained with SYBR green. Results: Notch-1 was highly expressed in SHED cultured in KGM and showed increase in density as the days progressed, while Jagged-1 showed a decrease. Jagged-2 on the other hand, showed a slight increase on day 3 followed by a decrease on day 7. However, Hes-1 was not expressed in SHED cultured in KGM. Nanog showed expression only on day 3 and gradually increased in expression on day 7. Conclusions: Notch signaling pathway associated molecules; Notch-1, Jagged-1, Jagged-2, and stem cell marker Nanog are expressed in SHED cultured in KGM which may be involved in the differentiation into epithelial-like cells in human dental pulp tissues. Keywords: receptors, notch; gene expression; stem cells; tooth, deciduous; culture media