A Genetically Engineered, Nonthrombogenic Cellular Lining for LVADs

Cl, Tock; Jp, Bosley; Sm, Parnis; Fj, Clubb; Mp, Macris; Oh, Frazier; Scott‐Burden, Timothy

doi:10.1097/00002480-199905000-00013

Cited by 5 publications

(2 citation statements)

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“…When exposed to shear stress, healthy ECs secrete nitric oxide (NO) that prevents clotting. 32,36,42,47,53 These shear stresses also influence the signaling between ECs and the surrounding SMCs, 3 even though they are not in physical contact. Furthermore, (1) ECs cultured with SMCs align with blood flow more rapidly 53 ; (2) EC's response to shear stress is improved if neighboring SMCs are preconditioned with cyclic strain 10 ; (3) EC/SMC coculture improves both SMC proliferation 28 and EC's lifetime 38 ; and (4) shear stress decreased inflammation in ECs if they were located near SMCs.…”

Section: Discussionmentioning

confidence: 99%

Vascular Wall Engineering Via Femtosecond Laser Ablation: Scaffolds with Self-Containing Smooth Muscle Cell Populations

et al. 2011

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For tissue-engineered vascular grafts to reach their full potential, three-dimensional (3D) cellular micro-integration will be necessary. In this study, we utilize femtosecond laser ablation to produce microchannels inside electrospun polycaprolactone (PCL) scaffolds. These microchannels potentially provide spatially controlled cell distributions approaching those observed in vivo. The ability of such laser-ablated microchannels to direct cell seeding was evaluated. The dimensions chosen were 100 μm wide, 100 μm deep and 10 mm long. Femtosecond laser ablation successfully produced these microchannels in the scaffolds without substantially altering the ~900 nm diameter fibers. Flow within these microchannels was studied by injecting fluorescent polystyrene bead solutions. Direct measurement of bead motion yielded an inlet velocity of 2.78 cm s(-1). This was used for modeling two-dimensional (2D) flow using computational fluid dynamics to estimate flow profiles within the microchannel. Successful demonstrations of bead flow were followed by seeding of 500,000 human coronary artery smooth muscle cells (HCASMCs) in proliferative medium at a rate of ~500 μL min(-1). Confocal microscopy and scanning electron microscopy confirmed that the HCASMCs were seeded down the full 10-mm length of the microchannel and stayed within its boundaries. Both nuclei and F-actin were observed within the seeded cells. The presence of F-actin filaments shows that the cells were adhered strongly to the scaffold and remained viable throughout the culture. The concept of "vascular wall engineering" producing intricate cell seeding through microchannels produced via femtosecond laser ablation was validated.

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Section: Discussionmentioning

confidence: 99%

Vascular Wall Engineering Via Femtosecond Laser Ablation: Scaffolds with Self-Containing Smooth Muscle Cell Populations

et al. 2011

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“…Because the shrouds on the HeartMate III impeller are designed to produce high‐shear backflows, we also compare the shrouded impeller design to a semi‐open design with no shroud on top of the impeller. Additionally, because there is interest in lining the LVADs' inner walls with cells to improve biocompatibility, we determined the shear stresses on these walls to assess the feasibility of endothelialization (18,19).…”

mentioning

confidence: 99%

Computational Fluid Dynamics Analysis to Determine Shear Stresses and Rates in a Centrifugal Left Ventricular Assist Device

Selgrade

Truskey

2012

Artificial Organs

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Axial flow left ventricular assist devices (LVADs) are a significant improvement in mechanical circulatory support. However, patients with these devices experience degradation of large von Willebrand factor (vWF) multimers, which is associated with bleeding and may be caused by high shear stresses within the LVAD. In this study, we used computational fluid mechanics to determine the wall shear stresses, shear rates, and residence times in a centrifugal LVAD and assess the impact on these variables caused by changing impeller speed and changing from a shrouded to a semi-open impeller. In both LVAD types, shear rates were well over 10 000/s in several regions. This is high enough to degrade vWF, but it is unclear if residence times, which were below 5 ms in high-shear regions, are long enough to allow vWF cleavage. Additionally, wall shear stresses were below the threshold stress of 10 Pa only in the outlet tube so it is feasible to endothelialize this region to enhance its biocompatibility.

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Biological Cardiac Assist Devices

Birla

2016

Tissue Engineering for the Heart

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A Genetically Engineered, Nonthrombogenic Cellular Lining for LVADs

Cited by 5 publications

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Vascular Wall Engineering Via Femtosecond Laser Ablation: Scaffolds with Self-Containing Smooth Muscle Cell Populations

Vascular Wall Engineering Via Femtosecond Laser Ablation: Scaffolds with Self-Containing Smooth Muscle Cell Populations

Computational Fluid Dynamics Analysis to Determine Shear Stresses and Rates in a Centrifugal Left Ventricular Assist Device

Biological Cardiac Assist Devices

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