Osteogenic Differentiation of Mesenchymal Stem Cells in their Native Niche Like Environment

Niche is an important microenvironment regulating stem cell's natural behavior and its fate. Mesenchymal Stem Cells (MSCs) are the most common cells used in bone tissue engineering. However, common culture procedures do not retain MSCs in their niche and apply in vitro expansion which can cause abnormal behavior. In this study, we propose that, by Keeping MSCs in their native niche, natural behavior of these cells and their interactions are maintained and the quality of differentiation will enhance. In our previous studies, we isolated MSCs kept in their native niche-like environment (native- MSCs) in the form of aggregates. Herein, in order to explore the osteogenic differentiation of these cells, they were isolated from bone marrow, and in vitro osteogenesis was assessed via alizarin red and real time PCR. It was observed that they differentiated after 6 days, which is remarkably faster than the conventional 21-day period. Higher expression of Runx2, Spp1 and alkaline phosphatase in native-MSCs also confirmed in vitro results. We also examine their attachment on poly (L-lactic acid) (PLLA) scaffold. In sum, native-MSCs exhibited faster differentiation than expanded MSCs which proves the importance of keeping stem cells in their niche. List of Abbreviation: Native-MSCs: MSCs which are kept in their niche like environment; Ex-MSCs: Expanded MSCs are common MSCs which isolate and expand based on their adherent properties

Assessment and Comparison the Effect of Exercise in Different Depth of Water On Postural Stability and Balance Recovery Strategies of Older People: A Clinical Trial

Background and Aims Water exercise is one of the most important interventions to reduce the risk of falls in the elderly. However, the effect of exercise in different depths of water has been less studied. Therefore, the aim of this study was to investigate and compare the effect of 8 weeks aquatic exercise in shallow and deep parts of the pool on postural stability and balance recovery strategies of the elderly.Methods In this quasi-experimental study, a total of 45 elderly males (60-70 years old) were randomly selected and classified into a control and 2 intervention groups of shallow and deep-water exercises. The intervention groups participated in a water exercise program for 8 weeks, while the control group did not receive any intervention. Postural stability and balance recovery strategies of all groups before and after the intervention were evaluated using Biodex balance system and Motion Analysis system, respectively. Finally, the Mixed ANOVA test was used for data analysis(P≤0.05).Results The results showed a significant increase in postural stability after conducting both types of water exercise programs(P0.05). The results also showed that there was no significant difference between the scores of two intervention groups(P>0.05).Conclusion In brief, it seems that both types of shallow and deep-water exercises can significantly improve the postural stability of the elderly. While these exercises cannot significantly change their balance recovery strategies. However, due to the more effective role of shallow water exercises in transferring balance strategies from the hip to ankle joint, it is recommended to pay more attention to the role of these exercises in improving the balance of older people

Effect of PLGA-IB on ICAM-1 and VCAM-1 expression in a mice adhesion model

Background: In this study, we compared the effect of ibuprofen (IB) while incorporating by Poly Lactic-co-Glycolic Acid (PLGA) nanofiber on expression of adhesion molecules ICAM-1 and VCAM-1 in a mice adhesion model.Materials and Methods: Using an adhesion model were induced in mice, PLGA-IB and PLGA membranes and IB were sutured between the abdominal wall and peritoneum after surgical operation to reveal the best membrane for prevention of postoperative adhesion bands by comparison of ICAM-1 and VCAM-1 expression.Results: Compared with other groups, PLGA-IB showed a greater ability to reduce ICAM-1 and VCAM-1 expression.Conclusion: These results suggested that in considering the FDA approved polymers, PLGA-IB could be introduced as a potential candidate for prevention of abdominal post-surgery inflammation and adhesion band formation after surgeries

Cytocompatibility of a conductive nanofibrous carbon nanotube/poly(L-lactic acid) composite scaffold intended for nerve tissue engineering

The purpose of this study was to fabricate a conductive aligned nanofibrous substrate and evaluate its suitability and cytocompatibility with neural cells for nerve tissue engineering purposes. In order to reach these goals, we first used electrospinning to fabricate single-walled carbon-nanotube (SWCNT) incorporated poly(L-Lactic acid) (PLLA) nanofibrous scaffolds and then assessed its cytocompatibility with olfactory ensheathing glial cells (OEC). The plasma treated scaffolds were characterized using scanning electron microscopy and water contact angle. OECs were isolated from olfactory bulb of GFP Sprague-Dawley rats and characterized using OEC specific markers via immunocytochemistry and flow cytometery. The cytocompatibility of the conductive aligned nano-featured scaffold was assessed using microscopy and MTT assay. We indicate that doping of PLLA polymer with SWCNT can augment the aligned nanosized substrate with conductivity, making it favorable for nerve tissue engineering. Our results demonstrated that SWCNT/PLLA composite scaffold promote the adhesion, growth, survival and proliferation of OEC. Regarding the ideal physical, topographical and electrical properties of the scaffold and the neurotrophic and migratory features of the OECs, we suggest this scaffold and the cell/scaffold construct as a promising platform for cell delivery to neural defects in nerve tissue engineering approaches

Osteogenic differentiation of mesenchymal stem cells cultured on PLLA scaffold coated with Wharton's jelly

Poly-L-lactic acid (PLLA) electrospun nanofiber scaffold is one of the most commonly used synthetic polymer scaffolds for bone tissue engineering application. However, PLLA is hydrophobic in nature, hence does not maintain proper cell adhesion and tissue formation, moreover, it cannot provide the osteo-inductive environment due to inappropriate surface characteristic and the lack of surface motives participating in the first cellular events. To modify these shortcomings different approaches have been used, among those the most commonly used one is coating of the surface of the electrospun nanofiber with natural materials. In this work Wharton’s jelly (WJ), a tissue which surrounds the umbilical cord vessels, reaches in high amounts of extracellular matrix (ECM) components mainly; collagen, hyaluronic acid and several sulphated glycosaminoglycans (GAGs) were used to cover the surface of electrospun PLLA nanofiber scaffolds. The surface morphology of the nanofiber scaffold was evaluated via scanning electron microscope, and the in vitro osteogenic differentiation potential was determined by MTT assay and common osteogenic marker tests such as alkaline phosphatase (ALP) activity and calcium deposition tests. Coating of WJ could not change the surface morphology and diameter of the nanofibers. However, WJPLLA scaffolds showed higher proliferation of human mesenchymal stem cells (MSC) than tissue culture plate (TCP) and pristine PLLA scaffolds, moreover, WJ-PPLA scaffold demonstrated significant alkaline phosphatase activity and calcium mineralization than either TCP or PLLA nanofiber scaffolds

Simultaneous Coating of Electrospun Nanofibers with Bioactive Molecules for Stem Cell Osteogenesis In Vitro

Objective: Mesenchymal stem cells (MSCs) are widely recognized as a promising cell type for therapeutic applicationsdue to their ability to secrete and regenerate bioactive molecules. For effective bone healing, it is crucial to select ascaffold that can support, induce, and restore biological function. Evaluating the scaffold should involve assessing MSCsurvival, proliferation, and differentiation. The principal aim of this investigation was to formulate composite nanofibrousscaffolds apt for applications in bone tissue engineering.Materials and Methods: In this experimental study, nanofibrous scaffolds were fabricated using Poly-L-lactic acid(PLLA) polymer. The PLLA fibers’ surface was modified by integrating collagen and hydroxyapatite (HA) nanoparticles.Results: The findings demonstrated that the collagen- and nanohydroxyapatite-modified electrospun PLLA scaffoldpositively influenced the attachment, growth, and osteogenic differentiation of MSCs.Conclusion: Coating the nanofiber scaffold with collagen and nanoparticle HA significantly enhanced the osteogenicdifferentiation of MSCs on electrospun PLLA scaffolds

Evaluation of indocyanine-mediated photodynamic therapy cytotoxicity on human osteoblast-like cells: an in vitro study

Introduction: Antimicrobial photodynamic therapy (aPDT) is an adjunctive non-invasive procedure for the management of periodontal tissue infection and deep periodontal pocket decontamination. However, the effects of this procedure on periodontal cells like osteoblasts that play a role in periodontal tissue repair and regeneration is not yet clear.Aim: This study aimed to investigate aPDT based on indocyanine green (ICG) on MG-63 osteoblast-like cells in vitro.Materials and methods: MG-63 cells were treated in 9 different groups: 1) Control (untreated cells), 2) ICG alone at a concentration of 1000 µg/mL, 3) ICG alone at a concentration of 2000 µg/mL, 4) diode laser irradiation alone for 30 s, 5) laser irradiation for 30 s combined with ICG with a concentration of 1000 µg/mL, 6) laser irradiation for 30 s combined with ICG at a concentration of 2000 µg/ mL, 7) laser irradiation alone for 60 s, 8) laser irradiation for 60 s combined with ICG at a concentration of 1000 µg/mL, and 9) laser irradiation for 60 s combined with ICG at a concentration of 2000 µg/mL. Cell viability was assessed by MTT assay in different groups.Results: In groups that were treated with 2000 µg/mL of ICG or diode laser irradiation at fluency of 39 J/cm2 for 60 s alone or in combination during ICG-aPDT, osteoblast-like cells viability decreased, remarkably.Conclusions: IGC-mediated aPDT with 1000 µg/mL of ICG combined with diode laser irradiation at fluency of 39 J/cm2 for 30 s is safe for MG-63 human osteoblast-like cells; however, higher concentration of ICG or laser irradiation time will increase cells death. There is still a need for more in vivo studies

Poly-l-lactic acid scaffold incorporated chitosan-coated mesoporous silica nanoparticles as pH-sensitive composite for enhanced osteogenic differentiation of human adipose tissue stem cells by dexamethasone delivery

Nowadays, the development of drug-loaded electrospun organic-inorganic composite scaffolds for tissue engineering application is an attractive approach. In this study, a composite scaffold of Poly-l-lactic acid (PLLA) incorporated dexamethasone (Dexa) loaded Mesoporous Silica Nanoparticles (MSN) coated with Chitosan (CS) were fabricated by electrospinning for bone tissue engineering application. The MSN was prepared by precipitation method. After that, Dexamethasone (Dexa) was loaded into MSNs (MSN-Dexa). In the following, CS was coated over the prepared nanoparticles to form MSN-Dexa@CS and then, were mixed to PLLA solution to form MSN-Dexa@CS/PLLA composite for electrospinning. The surface morphology, hydrophilicity, tensile strength and the bioactivity of the scaffolds were characterized. The osteogenic proliferation and differentiation potential were evaluated by MTT assay and by measuring the basic osteogenic markers: the activity of the enzyme alkaline phosphatase and the level of calcium deposition. The composite scaffolds prepared here have conductive surface property and have a better osteogenic potential than pure PLLA scaffolds. Hence, the controlled release of nanoparticle containing Dexa from composite scaffold supported the osteogenesis and made the composite scaffolds ideal candidates for bone tissue engineering application and pH-sensitive delivery of drugs at the site of implantation in tissue regeneration. Keywords Author Keywords:Mesoporous silica nanoparticles; electrospinning; Poly-l-lactic acid; chitosan; dexamethasone; composite scaffold; bone tissue engineering KeyWords Plus:DRUG-DELIVERY; BONE; SYSTEM; NANOFIBERS; SURFACE; POLY(L-LACTIDE); PROLIFERATION; CARTILAGE; RELEASE; PEPTID

Nanostructured Biomaterials for Tissue Engineered Bone Tissue Reconstruction

Bone tissue engineering strategies are emerging as attractive alternatives to autografts and allografts in bone tissue reconstruction, in particular thanks to their association with nanotechnologies. Nanostructured biomaterials, indeed, mimic the extracellular matrix (ECM) of the natural bone, creating an artificial microenvironment that promotes cell adhesion, proliferation and differentiation. At the same time, the possibility to easily isolate mesenchymal stem cells (MSCs) from different adult tissues together with their multi-lineage differentiation potential makes them an interesting tool in the field of bone tissue engineering. This review gives an overview of the most promising nanostructured biomaterials, used alone or in combination with MSCs, which could in future be employed as bone substitutes. Recent works indicate that composite scaffolds made of ceramics/metals or ceramics/polymers are undoubtedly more effective than the single counterparts in terms of osteoconductivity, osteogenicity and osteoinductivity. A better understanding of the interactions between MSCs and nanostructured biomaterials will surely contribute to the progress of bone tissue engineering

Effect of Eight Weeks of Water Exercises on Deep Part of the Pool on the Static Balance of the Elderly Man

Objectives The purpose of this study was to investigate the effect of deep aquatic exercises on balance among elderly men.  Methods & Materials Thirty elderly men voluntarily participated in this experiment. Subjects were randomly divided into two equal groups including experimental and control groups. The experimental group participated in a deep aquatic exercise program that consisted of 60-minutes sessions three times a week for eight weeks, while the control group was not into any exercise. Postural stability (static balance) was assessed before and after the program as pre-test and post-test by Biodex Balance System (BBS) respectively. Independent sample t-test and paired sample t-test (P≤0.05) were performed on outcome variables. Results The results of the comparison between the two groups of 15 individuals in terms of demographic and anthropometric features[experimental group with mean age of (65.50±3.481), height (168.10±5.215), weight (70.865±7.775) and body mass index (24.781±2.483) and the control group with an average age of (66.50±3.232), height (169.20±6.314), weight (71.322±8.531) and body mass index (24.982±3.535) were divided], the two groups showed no difference in results is homogeneity. The findings of the study showed that aquatic exercises program has significant effect on the static balance (P≤0.05). The results indicated significant differences between the subjects of experimental and control groups after the exercise program, and also paired sample t-test showed significant differences between pre and post-tests in experimental group while no differences observed in control group.  Conclusion According to this study, doing the deep-aquatic exercises is effective on improving the static balance of old people and reducing their risk of falling.&nbsp