Impact of disturbed flow and arterial stiffening on mechanotransduction in endothelial cells.

Disturbed flow promotes progression of atherosclerosis at particular regions of arteries where the recent studies show the arterial wall becomes stiffer. Objective of this study is to show how mechanotransduction in subcellular organelles of endothelial cells (ECs) will alter with changes in blood flow profiles applied on ECs surface and mechanical properties of arterial wall where ECs are attached to. We will examine the exposure of ECs to atherogenic flow profiles (disturbed flow) and non-atherogenic flow profiles (purely forward flow), while stiffness and viscoelasticity of arterial wall will change. A multicomponent model of endothelial cell monolayer was applied to quantify the response of subcellular organelles to the changes in their microenvironment. Our results show that arterial stiffening alters mechanotransduction in intra/inter-cellular organelles of ECs by slight increase in the transmitted stresses, particularly over central stress fibers (SFs). We also observed that degradation of glycocalyx and exposure to non-atherogenic flow profiles result in significantly higher stresses in subcellular organelles, while degradation of glycocalyx and exposure to atherogenic flow profiles result in dramatically lower stresses in the organelles. Moreover, we show that increasing the arterial wall viscoelasticity leads to slight increase in the stresses transmitted to subcellular organelles. FAs are particularly influenced with the changes in the arterial wall properties and viscoelasticity. Our study suggests that changes in viscoelasticity of arterial wall and degradation state of glycocalyx have to be considered along with arterial stiffening in designing more efficient treatment strategies for atherosclerosis. Our study provides insight into significant role of mechanotransduction in the localization of atherosclerosis by quantifying the role of ECs mechanosensors and suggests that mechanotransduction may play a key role in design of more efficient and precision therapeutics to slow down or block the progression of atherosclerosis.

Impact of Wound Dressing on Mechanotransduction within Tissues of Chronic Wounds.

Chronic wounds are significant public health problems impacting the health-related quality of individuals' lives (due to disability, decreased productivity, and loss of independence) and an immense economic burden to healthcare systems around the world. In this study, our main objective is to investigate how mechanotransduction can impact the healing process in chronic wounds. We have developed new three-dimensional models of wound tissue to study the distribution of forces within these tissues exerted by wound dressings with different characteristics. The roles of mechanical forces on wound healing have gained significant clinical attention; the application of mechanical forces is expected to influence the physiology of tissue surrounding a wound. We aim to investigate whether the force transmission within wound tissue is impacted by the dressing characteristics and whether this impact may differ with wound tissue's properties. Our results show that wound dressings with lower stiffnesses promote force transmission within a wound tissue. This impact is even more significant on stiffer wound tissues. Furthermore, we show that size of wound dressing alters forces that transmit within the wound tissue where dressings with 9 cm length show higher stresses. The wound tissue stiffening has been associated with healing of a wound. Our results demonstrate that wounds with stiffer tissue experience higher stresses. Taken all together, our findings suggest that low stiffness of wound dressing and its size may be introduced as a criterion to explain parameters predisposing a chronic wound to heal. This study's findings on the role of dressings and tissue characteristics demonstrate that precision dressings are required for wound management and understanding how a dressing impacts mechanotransduction in wound tissue will lead to design of novel dressings promoting healing in chronic wounds.

Mechanotransduction in Endothelial Cells in Vicinity of Cancer Cells.

Introduction-Local hemodynamics impact the mechanotransduction in endothelial cells (ECs) lining the vascular network. On the other hand, cancer cells are shown to influence the local hemodynamics in their vicinity, in microvasculature. The first objective of present study is to explore how cancer cell-induced changes in local hemodynamics can impact the forces experienced by intra/inter-cellular organelles of ECs that are believed to play important roles in mechanotransduction. Moreover, extracellular matrix (ECM) stiffening has been shown to correlate with progression of most cancer types. However, it is still not well understood how ECM stiffness impacts ECs mechanosensors. The second objective of this study is to elucidate the role of ECM stiffness on mechanotransduction in ECs. Methods-A three-dimensional, multiscale, multicomponent, viscoelastic model of focally adhered ECs is developed to simulate the force transmission through ECs mechanosensors [actin cortical layer, nucleus, cytoskeleton, focal adhesions (FAs), and adherens junctions (ADJs)]. Results-Our results show that cancer cell-altered hemodynamics results in significantly high forces transmitted to subcellular organelles of ECs which are in vicinity of cancer cells. This impact is more drastic on stress fibers (SFs) both centrally located and peripheral ones. Furthermore, we demonstrate that ADJs, FAs, and SFs experience higher stresses in ECs attached to stiffer ECM. Impact of ECM stiffness is particularly significant in ECs exposed to fluid shear stresses of 2 Pa or lower. This finding reveals the role of organ-specific stiffness in promoting cancer cell transmigration even in capillaries larger than cancer cell diameter. Conclusions-ÊCancer cell-induced-changes in ECs mechanotransduction represents an important potential mechanism for cancer cell transmigration in the microvasculature particularly with stiffer ECM. The identification of ECs mechanosensors involved in early stages of EC-cancer cell interaction will help with developing more efficient therapeutic interventions to suppress cancer cell transmigration in the microvasculature.