ORCID Profile
0000-0003-3605-6770
Current Organisation
Pasteur Institute of Iran
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Publisher: Wiley
Date: 10-08-2012
DOI: 10.1111/J.1525-1594.2012.01507.X
Abstract: Hydrostatic pressure (HP) plays an essential role in regulating function of chondrocytes and chondrogenic differentiation. The objective of this study was to examine effects of intermittent HP on chondrogenic differentiation of human adipose-derived mesenchymal stem cells (hASCs) in the presence or absence of chemical chondrogenic medium. Cells were isolated from abdominal fat tissue and confirmed for expression of ASC surface proteins and differentiation potential. Passage 3 pellets were treated with chemical (growth factor), mechanical (HP of 5 MPa and 0.5 Hz with duration of 4 h/day for 7 consecutive days), and combined chemical-mechanical stimuli. Using real-time polymerase chain reaction, the expression of Sox9, collagen II, and aggrecan as three major chondrogenic markers were quantified among three experimental groups and compared to those of stem cells and human cartilage tissue. In comparison to the chemical and mechanical groups, the chemical-mechanical group showed the highest expression for all three chondrogenic genes close to that of cartilage tissue. Results show the beneficial role of intermittent HP on chondrogenic differentiation of hASCs, and that this loading regime in combination with chondrogenic medium can be used in cartilage tissue engineering.
Publisher: Informa UK Limited
Date: 02-11-2015
DOI: 10.1080/15419061.2016.1265949
Abstract: Although substrate stiffness has been previously reported to affect various cellular aspects, such as morphology, migration, viability, growth, and cytoskeletal structure, its influence on cell adherence has not been well examined. Here, we prepared three soft, medium, and hard polyacrylamide (PAAM) substrates and utilized AFM to study substrate elasticity and also the adhesion and mechanical properties of endothelial cells in response to changing substrate stiffness. Maximum detachment force and cell stiffness were increased with increasing substrate stiffness. Maximum detachment force values were 0.28 ± 0.14, 0.94 ± 0.27, and 1.99 ± 0.59 nN while Young's moduli of cells were 218.85 ± 38.73, 385.58 ± 131.67, and 933.20 ± 428.92 Pa for soft, medium, and hard substrates, respectively. Human umbilical vein endothelial cells (HUVECs) showed round to more spread shapes on soft to hard substrates, with the most organized and elongated actin structure on the hard hydrogel. Our results confirm the importance of substrate stiffness in regulating cell mechanics and adhesion for a successful cell therapy.
Publisher: American Scientific Publishers
Date: 12-2013
Publisher: Wiley
Date: 06-2010
DOI: 10.1111/J.1525-1594.2010.01003.X
Abstract: Endothelial cells are remodeled when subjected to cyclic loading. Previous in vitro studies have indicated that frequency, strain litude, and duration are determinants of endothelial cell morphology, when cells are subjected to cyclic strain. In addition to those parameters, the current study investigated the effects of strain waveform on morphology of cultured endothelial cells quantified by fractal and topological analyses. Cultured endothelial cells were subjected to cyclic stretch by a designed device, and cellular images before and after tests were obtained. Fractal and topological parameters were calculated by development of an image-processing code. Tests were performed for different load waveforms. Results indicated cellular alignment by application of cyclic stretch. By alteration of load waveform, statistically significant differences between cell morphology of test groups were observed. Such differences are more prominent when load cycles are elevated. The endothelial cell remodeling was optimized when the applied cyclic load waveform was similar to blood pressure waveform. Effects of load waveform on cell morphology are influenced by alterations in load litude and frequency. It is concluded that load waveform is a determinant of endothelial morphology in addition to litude and frequency, and such effect is elevated by increase of load cycles. Due to high correlation between fractal and topological analyses, it is recommended that fractal analysis can be used as a proper method for evaluation of alteration in cell morphology and tissue structure caused by application of external stimuli such as mechanical loading.
Publisher: Trans Tech Publications, Ltd.
Date: 10-2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/JBBTE.15.63
Abstract: Articular Cartilage Defects Are a Recent Critical Orthopaedic Issue. Hydrogels Have Been Widely Used in Soft Tissue Engineering Scaffolds as their Structures Are Similar to the Macromolecular-Based Components in the Human Body. Hydrogels Including those Based on Poly(vinyl Alcohol) (PVA) and Chitosan Are of Considerable Interest for Utilization in the Field of Tissue Engineering because of their Appropriate Biocompatibility. PVA Gels Can Be Formed by Chemical or Physical Crosslinking. the “freezing-Thawing” (FT) Process Is the Most Mild, Facile and Effective Method to Produce Physically Crosslinked PVA Gel, because it Does Not Require the Presence of the Crosslinking Agent that May Cause Toxicity. in this Study Hydrogels Based on PVA and Chitosan in Different Blend Ratios Were Prepared, and the Effect of the Freeze-Thaw Cycles and Glutaraldehyde on the Hydrogel Properties Was Investigated. the Results Showed that Freeze-Thaw Cycles Increased the Tensile Strength and the S les’ Resistance to Degradation. the Biocompatibility of the Hydrogels Was Analysed Using Chondrocyte Cells Separated from Distal Femur of Men. Cell Toxicity Assay Performed for Measurement of Cell Viability of the S les Indicated Biocompatibility.
Publisher: Springer Science and Business Media LLC
Date: 23-03-2013
Publisher: Wiley
Date: 30-10-2013
DOI: 10.1002/CBIN.10194
Abstract: Myocardium is prone to mechanical stimuli among which pulsatile blood flow exerts both radial and longitudinal strains on the heart. Recent studies have shown that mechanical stimulation can notably influence regeneration of cardiac muscle cells. GATA4 is a cardiac-specific transcription factor that plays an important role in late embryonic heart development. Our study aimed at investigating the effect of equiaxial cyclic strain on GATA4 expression in adipose-derived (ASCs) and bone marrow-derived (BMSCs) mesenchymal stem cells. For this reason, both ASCs and BMSCs were studied in four distinct groups of chemical, mechanical, mechano-chemical and negative control. According to this categorisation, the cells were exposed to cyclic mechanical loading and/or 5-azacytidine as the chemical factor. The level of GATA4 expression was then quantified using real-time PCR method on the first, fourth and seventh days. The results show that: (1) equiaxial cyclic stimulation of mesenchymal stem cells could promote GATA4 expression from the early days of induction and as it went on, its combination with chemical factor elevated expression (2) cyclic strain could accelerate GATA4 expression compared to the chemical factor (3) in this regard, these results indicate a higher capacity of ASCs than BMSCs to express GATA4.
Publisher: Elsevier BV
Date: 03-2015
DOI: 10.1016/J.JMBBM.2014.12.013
Abstract: Human mesenchymal stem cells (hMSCs) have shown promising potential in the field of regenerative medicine particularly in vascular tissue engineering. Optimal growing of MSCs into specific lineage requires a thorough understanding of the role of mechanobiology in MSC metabolism. Although effects of external physical cues (mechanical stimuli through external loading and scaffold properties) on regulation of MSC differentiation into Smooth muscle (SM) lineage have attracted widespread attention, fewer studies are available on mechanical characterization of single engineered MSCs which is vital in tissue development through proper mechanotransductive cell-environment interactions. In this study, we investigated effects of uniaxial tensile strain and transforming growth factor-β1 (TGF-β1) stimulations on mechanical properties of engineered MSCs and their F-actin cytoskeleton organization. Micropipette aspiration technique was used to measure mechanical properties of MSCs including mean Young׳s modulus (E) and the parameters of standard linear viscoelastic model. Compared to control s les, MSCs treated by uniaxial strain either with or without TGF-β1 indicated significant increases in E value and considerable drop in creep compliance curve, while s les treated by TGF-β1 alone met significant decreases in E value and considerable rise in creep compliance curve. Among treated s les, uniaxial tensile strain accompanied by TGF-β1 stimulation not only caused higher stimulation in MSC differentiation towards SM phenotype at transcriptional level, but also created more structural integrity in MSCs due to formation of thick bundled F-actin fibers. Results can be applied in engineering of MSCs towards functional target cells and consequently tissue development.
Publisher: SAGE Publications
Date: 10-2015
DOI: 10.5301/IJAO.5000433
Abstract: In this study, we examined chondrogenic regulation of 2 types of mesenchymal stem cells seeded on the bioengineered substrate in monolayer cultures under mechanically defined conditions to mimic the in vivo microenvironment of chondrocytes within articular cartilage tissues. Human adipose-derived mesenchymal stem cells (ASCs) and bone marrow mesenchymal stem cells (BSCs) were exposed to 0.2 Pa shear stress, 3 MPa cyclic hydrostatic pressure, and combined loading with different sequences on chemically designed medical-grade silicone rubber, while no soluble growth factors were added to the culture medium. The expression levels of chondrogenic-specific genes of SOX9, aggrecan, and type II collagen (Col II) were measured. Results were compared to those of cells treated by biological growth factor. Gene expression patterns were dependent on the loading regime. Moreover, the source of mesenchymal stem cells (adipose or bone marrow) was influential in gene expression. Overall, enhanced expression of chondrogenic markers was found through application of mechanical stimuli. The response was generally found to be significantly promoted when the 2 loading regimes were superimposed. Differentiation of ASCs was shown by a modest increase in gene expression profiles. In general, BSCs expressed higher levels of chondrogenic gene expression than ASCs after 3 weeks. A greater effect on Col II and SOX9 mRNA expression was observed when combined loadings were applied. Results may be applied in determining the proper loading sequence for obtaining functional target cells in cartilage engineering applications.
Publisher: World Scientific Pub Co Pte Ltd
Date: 03-07-2014
DOI: 10.1142/S0219519414500547
Abstract: Cartilage tissue engineering is a promising treatment for damaged or diseased cartilage that requires thorough understanding of influential parameters involved in chondrogenic differentiation. This study examined how 4-h application of cyclic hydrostatic pressure (CHP) of 5 MPa at 0.5 Hz could modulate chondroinduction of human adipose-derived mesenchymal stem cells (hAMSCs) in vitro. Four groups were examined including a negative control group, a chemical group treated by growth factor for 10 days, a mechanical group exposed to 4-h loading on the 10th day of pellet culture without any chondrogenic stimulator, and finally a chemical-mechanical group subjected to both growth factor and loading. Application of cyclic hydrostatic pressure increased the expression of chondrogenic genes, including sox9 and aggrecan to higher levels than those of the chemical group. This study indicates that cyclic hydrostatic pressure initiates and enhances the chondrogenic differentiation of mesenchymal stem cells with or without growth factors in vitro and confirms the important role of hydrostatic pressure during chondrogenesis in vivo.
Publisher: Informa UK Limited
Date: 10-2010
DOI: 10.3109/03091902.2010.514974
Abstract: Excessive wall circumferential stress in arteries caused by luminal pressure leads to endothelial damage and clinical consequences. In addition to circumferential stress, arterial wall contains residual stress with compressive and tensile components on intima and adventitia sides. The intimal compressive component compensates part of tensile stress induced by blood pressure, hence reduces severity of endothelial tension. The opening angle caused by radial cut of arterial ring defines residual stress. In this study, finite element modelling is used to evaluate residual stress in a lamellar model of human aorta with differing opening angle and elastic modulus. Results show non-linear residual stress profiles across wall thickness, influenced by structural and mechanical parameters. Elevation of opening angle from 50° to 90° leads to increase of intimal compressive component compensating up to 32.6% of the pressure-induced tensile stress. Results may be applied in study of endothelial injury caused by excessive stress in situations such as aging, hypertension and atherosclerosis.
Publisher: SAGE Publications
Date: 08-02-2013
DOI: 10.5301/IJAO.5000242
Abstract: It has been hypothesized that application of the micromechanical environment that target cells experience in vivo enhances functionality of differentiated cells. Vascular endothelial cells, functioning at the interface of the blood-vessel wall, are vital to the performance of the cardiovascular system. They are subject to shear and tensile stresses induced by blood flow and pressure, respectively. This study investigated effects of shear/tensile stresses on endothelial differentiation of adipose-derived mesenchymal stem cells (ASCs) utilizing a custom-made bioreactor capable of applying both shear and tensile stresses. The loading values of 10% cyclic stretch, 0-2.5 dyn/cm 2 cyclic shear stress, and combined loadings were used. To examine the extent of mechanical and chemical stimuli in acquisition of endothelial characteristics by ASCs, the expression of three major endothelial genes were quantified when ASCs were treated by three loading regimes and endothelial growth factor for three different durations (1, 2, and 7 days). In general, cyclic stretch decreased expression of FLK-1 and vWF, while cyclic shear elevated expression levels. The combined loading regime had minor effects on the expression of the two markers. All types of loadings significantly enhanced the expression level of VE-cadherin with the most prominent increase by combined loading. It was concluded that applying different loading regimes assists in adjusting the expression level of endothelial markers to achieve functional endothelial cells for cardiovascular engineering.
Publisher: IEEE
Date: 12-2012
Publisher: Wiley
Date: 28-01-2015
DOI: 10.1002/CBIN.10443
Abstract: It has been well established that biomechanical environment can influence functionality of biological cells. There are evidences that show mechanical cyclic stretch can promote smooth muscle cell (SMC) markers in endothelial cells (ECs). The objective of this study was to determine whether mechanical stimuli in the forms of uniaxial and equiaxial cyclic stretches (UNCS and EQCS) can affect endothelial and smooth muscle gene expressions in mRNA level of human umbilical vein endothelial cells (HUVECs). For this purpose, 10% uniaxial UNCS and EQCS (60 cycles/min for 24 h) were applied on HUVECs, and using real-time PCR expressions of three EC specific markers, vascular endothelial growth factor receptor-2 (VEGFR-2, also known as FLK-1), von Willebrand Factor (vWF) and vascular endothelial-cadherin (VE-cadherin) and two SMC specific genes, α-smooth muscle actin (α-SMA) and smooth muscle myosin heavy chain (SMMHC) were quantified. Moreover, alterations in cell height were analyzed by atomic force microscopy (AFM). Results showed that cyclic UNCS for 24 h downregulated the expression of all EC markers and upregulated the expression of all SMC markers while low effects on HUVECs height were observed. Cyclic EQCS in the same conditions resulted in minor effect on SMC gene expression in HUVECs, while led to strong reduction in vWF with no significant change in other two endothelial genes. Cyclic EQCS considerably elevated cell height. Results proposed that ECs can transdifferentiate to SMC phenotype under specific microenvironmental conditions.
Publisher: Wiley
Date: 12-02-2014
DOI: 10.1002/CBIN.10237
Abstract: Biomechanical environments affect the function of cells. In this study we analysed the effects of five mechanical stimuli on the gene expression of human umbilical vein endothelial cells (HUVECs) in mRNA level using real-time PCR. The following loading regimes were applied on HUVECs for 48 h: intermittent (0-5 dyn/cm(2) , 1 Hz) and uniform (5 dyn/cm(2) ) shear stresses concomitant by 10% intermittent equiaxial stretch (1 Hz), uniform shear stress alone (5 dyn/cm(2) ), and intermittent uniaxial and equiaxial stretches (10%, 1 Hz). A new bioreactor was made to apply uniform/cyclic shear and tensile loadings. Three endothelial suggestive specific genes (vascular endothelial growth factor receptor-2 (VEGFR-2, also known as FLK-1), von Willebrand Factor (vWF) and vascular endothelial-cadherin (VE-cadherin)), and two smooth muscle genes (α-smooth muscle actin (α-SMA) and smooth muscle myosin heavy chain (SMMHC)) were chosen for assessment of alteration in gene expression of endothelial cells and transdifferentiation toward smooth cells following load applications. Shear stress alone enhanced the endothelial gene expression significantly, while stretching alone was identified as a transdifferentiating factor. Cyclic equiaxial stretch contributed less to elevation of smooth muscle genes compared to uniaxial stretch. Cyclic shear stress in comparison to uniform shear stress concurrent with cyclic stretch was more influential on promotion of endothelial genes expression. Influence of different mechanical stimuli on gene expression may open a wider horizon to regulate functions of cell for tissue engineering purposes.
Location: Iran (Islamic Republic of)
Location: Iran (Islamic Republic of)
No related grants have been discovered for nooshin haghighipour.