Journal of Regeneration, Reconstruction and Restoration
Volume:2 Issue: 1, Winter 2017

High surface/volume ratio and 3-dimensionality of nanofibers increases cell-scaffold interactions and promote migration and proliferation of cells. Wet electrospinning is a variant of electrospinning technology that is utilized to produce nanofibrous scaffolds. Altering the parameters governing the wet electrospinning process such as applied voltage, polymer concentration, composition and depth of the coagulation bath, and tip to bath distance can affect the morphology of the produced scaffolds. In this study, the influence of various coagulation baths on the physicochemical properties of the wet-electrospun nanofibers was investigated.

Poly (ε-caprolactone)/Poly (L-lactic) acid 15% (w/v) blends under an applied voltage of 15 kV, and a tip-to-bath distance of 10 cm. were used to prepare fibrous scaffolds via wet-electrospinning technique into aqueous solution of sodium hydroxide (NaOH) (pH~13), distilled water, ethanol, water/ethanol (3:7) (v/v) and water/ethanol/methanol (6:2:2) (v/v). The final products were characterized by scanning electron microscopy (SEM), liquid displacement technique, contact angle measurement, compressive and tensile tests. As well as, cell adhesion and cell viability through human adipose-derived stem cells (hADSCs) cell culture.

Wet-electrospun fibers, except in the almost fully beaded structure of water/ethanol (3:7) (v/v) specimen exhibited random, dispersive and non-woven morphology under SEM observation. The coagulation bath composition significantly influenced on porosity, wettability, mechanical properties and biocompatibility of the scaffolds. The porosity measurement via liquid displacement method showed that except for the specimen in which the blend was spun into NaOH, other scaffolds could not meet the accepted ideal porosity percentage of above 80%. According to the contact angle measurement data, it was expected that all scaffolds experience low cellular attachment and proliferation. Conversely, in vitro hADSCs culture demonstrated that the scaffolds presented a non-toxic environment and enhanced cell proliferation and attachment.

The data indicated that the scaffold spun into NaOH was the best candidate among other specimens to culture hADSCs.

High-cell density culture is based on the chondrogenic differentiation of human mesenchymal stem cells (hMSCs), and because the high density of cell and reduced oxygen tension are effective in chondrogenic differentiation. In the present paper, there will be a review about the methods of chondrogenic differentiation of hMSCs that utilized in in vitro and in vivo chondrogenic differentiation of stem cells for treatment of osteoarthritis. There are three High-cell density culture systems; micromass, pellet culture, and alginate culture have been used to induce chondrogenic differentiation of hMSCs.Transplanted naive MSCs can cause problems such as heterogeneous populations. To overcome this problem, new strategies for inducing differentiation of MSCs are needed. One possibility is a cell culture system. Collagen II and aggrecan are critical protein in chondrogenic differentiation. In all different methods, real time RT-PCR analysis demonstrates that collagen II and aggrecan mRNA are up regulated while collagen X and collagen I mRNA are down regulated. So these three high-density cell culture systems have been approved for chondrogenic differentiation. On the other hand, In micromass method, the induced-cartilage tissues are larger, more homogenous and rich in cartilage specific collagen II, but collagen I, collagen X and hypertrophic chondrocyte features are markedly decreased compared to other culture system. Thus, the micromass culture system is the best tool for in vitro chondrogenic differentiation studies.

Satellite cells known as the main regenerating cell types in skeletal muscle which can be isolated using pre-plate technique due to weak or slow adhesive interactions with satellite cells. Although, there are some issues about digestion of muscle tissue and isolation of satellite cells, which highlight need for an efficient procedure. Also, the employment of a nanofibrous surface can facilitate the attachment of satellite cells to reach matured muscle tissue. On the other hand, polyacrylonitrile (PAN) has been reported as a biocompatible polymer that can be electrospun into a nonwoven membrane.

Herein, a modified digestion and pre-plate protocol was established for the enrichment of satellite cells. Also, a PAN electrospun scaffold was used to provide a higher surface area for cell attachment compared to tissue culture polystyrene (TCPS). However, the surface of prepared scaffold was modified with plasma treatment to progress cell adhesion.

The corresponding scaffold was examined with scanning electron microscopy (SEM) and tensile examination. The enriched cells, which exhibited a close gene expression pattern with satellite cells, seeded on this electrospun PAN membrane. The cultured satellite cells showed a good tendency to surface of PAN scaffold and also a higher rate of cell proliferation. Subsequently, the cells were induced to more expression of specific muscle genes compared to TCPS group.

As a whole, satellite cells could mature to multinuclear cells using PAN scaffold as a function of efficient mechanical property and also higher surface area.

dental pulp stem cells (DPSCs) have been shown to have great capacity to differentiation toward the osteoblast lineage and they can be considered as a great cell source for bone tissue engineering. The vitamin K family, especially vitamin K2 (MK-4), have been shown to have an osteoprotective role. In this study, we have investigated the effect of various concentrations of MK-4 on differentiation of DPSCs into osteoblast.

DPSCs were isolated and characterized to expression the mesenchymal markers. These cells were treated with osteogenic medium with and without of various concentrations of MK-4 for 14 days. Osteogenic capability and extracellular calcium deposition were assessed by ALP assay and alizarin red staining, respectively, at zero, 7, 14 days after induction.

the additional ofMK-4 at concentration of 10 μM with osteogenic medium had a significant effect on differentiation DPSCs into osteoblast (P<0.05) at 14 day, as it confirmed by both ALP activity assay and alizarin red staining.

MK-4 can promote differentiation of DPSCs into osteoblast in vitro so have a potential to be considered in improvement of cell-based bone tissue engineering therapies

Induced pluripotent stem cells (iPSCs) can be generated from different source of cells with different efficiencies. Two DNA methyltransferases DNMT1 and DNMT3A have been shown to regulate epigenetically the gene expression involved in cell viability and reprogramming. L-ascorbic acid (L-AA) is a chemical factor that can accelerate reprogramming. Here, we sought to investigate the effect of L-AA on DNMT1 and DNMT3A expressions.

First, mouse embryonic fibroblasts at passage 3 were cultured in the presence of 10 μg/ml L-AA days for 5 days. Then, DNMT1 and DNMT3A expressions were determined using real-time PCR at days 3 and 5.

It was showed that L-AA could enhance DNMT-1 expression which involve in cell viability and decrease the DNMT3A which involve in cell differentiation.

The results therefore suggest a new insight into L-AA mechanism impact on reprogramming process

Mesenchymal stem cells (MSCs) are easy to isolate, culture, and manipulate in ex-vivo culture. MSCs were identified in several other organs such as umbilical cord which is focused in present project. Type 1 Diabetes mellitus is caused due to e damage of the pancreatic beta cells resulting in absolute insulin insufficiency. Transplantation of insulin-producing islet cells could be considered as an effective therapy for type 1 diabetes.

In this project we aimed to enzymatically isolate stem cells from human umbilical cord. The mesenchymal properties of these isolated cells were checked by flow cytometry technique. Their differentiation potentials were further studied, particularly with respect to islet like clusters (ILCs) which were generated through a three steps induction protocol. The amount of secreted insulin has been measured using insulin ELISA kit.

Stem cells were successfully isolated from human umbilical cord. Cells expressed high level of mesenchymal markers and they had both osteogenenic and adipogenic differentiation potential. Through a 10 days of islet induction, most of the obtained islet like aggregates were positive for DTZ, a zinc-chelating agent known to selectively stain pancreatic β-cells. They were also able to secrete insulin.

MSCs isolated from the human umbilical could be differentiated into ILCs that possess the ability to produce insulin. Therefore human umbilical cord blood-derived MSCs (hUCMSCs) seem to be an excellent source of stem cells that can be used in the therapeutic procedures for type 1 diabetes.

Transcutaneous electrical nerve stimulation (TENS) has been used to reduce post-operative pain. The aim of this study was to assess the efficacy of TENS as an adjunctive pain relief measure after impacted third molar surgery.

In this double-blind randomized clinical trial, patients requiring surgical extraction of third molars (Class 2 and B of Pell and Gregory) were randomly divided into two groups. Group I subjects received TENS immediately after surgery along with analgesics (400 mg Gelofen). In group II, patients received 400 mg Gelofen immediately post-operation (control group). The pain intensity was evaluated using a visual analog scale (VAS) eight hours after surgery. The independent t-test was applied to compare pain intensity between the two groups.

Three-hundred subjects were studied in two groups (each group had 150 participants). The mean pain intensity score was 3.7±1.43 in group I and 4.36±1.66 in group II. A significant difference was noted for pain intensity between the two groups (P=0.001).

Use of TENS may decrease pain intensity during the first eight hours after impacted third molar surgery and may obviate the need for additional doses of non-steroidal anti-inflammatory drugs (NSAIDs).

Dipping technique is commonly used by dental technicians to color zirconia ceramics; however, its impact on the bond between zirconia and resin cements is unclear. This in vitro study aimed to evaluate the microtensile bond strength (µTBS) between a zirconia ceramic and Panavia F2.0 resin cement after dipping in coloring liquids with different shades.

Twenty zirconia blocks were dipped in four different shades of coloring liquids including A3, B2, C1, and D4, while five blocks were not colored for the control. All zirconia blocks were cemented to corresponding composite blocks using Panavia F2.0 resin cement. Zirconia-cement-composite blocks were cut into one hundred microbar specimens (1×1×10 mm). The specimens were divided into five studied groups according to their shade (A3, B2, C1, D4, control) and were subjected to an aging process. A microtensile tester applied tensile forces to the specimens, till the fracture occurred, and measured the µTBS values. One-way ANOVA and Tukey’s Post Hoc were used to analyze the data (P<0.05). Optical microscopy and scanning electron microscopy were employed to evaluate failure modes and surface structure.

The µTBS values for the groups showed significant differences (P<0.0001). D4 had the highest, and B2 had the lowest µTBS values. C1 (P=0.69) and A3 (P=0.89) showed no significant differences in the µTBS values compared with the control. Failure modes evaluation represented the lowest rate of adhesive failure for D4 (10%), and the highest in this respect for B2 (80%).

Depending on the shade of coloring liquids, dipping had positive, negative, or no effects on the µTBS of zirconia ceramic to Panavia F2.0 resin cement.