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Figure 4: Examples of engineering strategies used to study the effects of anisotropic versus isotropic extracellular forces on cultured stem cells. Pig bone marrow-derived stem cells, subjected to cyclic hydrostatic pressure, (a) retain a spherical morphology when encapsulated in softer agarose, whereas (b) spread when encapsulated in stiffer fibrin hydrogels. Reprinted and adapted from [11] with permission from Elsevier. Rat bone marrow-derived stem cells (c) appear randomly distributed in unsolicited culture conditions, whereas (f) anisotropic strain induces cell elongation and upregulation of cardiomyocyte-related markers. Adapted with permission from [12]. In human bone marrow-derived mesenchymal stem cells and meniscal fibrochondrocytes cultured on a randomly organized nanofibrous scaffold, (d) biaxial strain induces a roundish shape of the cell nucleus, with small protrusion in all directions, while (e) uniaxial strain determines an elongated morphology of the cell nucleus. Reprinted and adapted from [13] with permission from Elsevier.