Biology subjects

Nechipurenko, D. Y.

Publications and source records attributed to Nechipurenko, D. Y..

3 recordsLinked to original sources

bioRxiv2024

Staying on track: collagen fibers orientation strongly affects thrombi formation at high shear

ObjectiveSubendothelial matrix exhibits a distinctive organization, with collagen fibers beneath the endothelium oriented primarily parallel to the flow and comprising mainly types III and I collagen in arteries and arterioles. However, the significance of such organization in initiating rapid thrombus formation remains unclear. Approach and ResultsTo investigate the role of collagen fibers orientation in triggering thrombus formation we utilized the in vitro microfluidic model of thrombosis. Human whole blood was perfused through a system with collagen fibers oriented either parallel or perpendicular to the flow, and the primary stages of platelet adhesion and thrombi growth were analyzed using a high-speed fluorescence microscopy. At the shear rates of 200 and 1000 s-1 no significant difference in thrombogenicity was observed between the collagen fibers orientations. However, at a high shear rate of 2000 s-1, thrombi on the parallel fibers were higher and covered a much larger area than those on the perpendicular ones. High-speed microscopy revealed that platelets were able to achieve stable adhesion only after translocating for over several seconds under all studied conditions. Analysis of single platelets dynamics revealed that platelets interacted longer and translocated farther during their interaction with parallel fibers at high shear, suggesting that flow-aligned fibers facilitate stable adhesion by enabling platelets to translocate along them and stay in contact with collagen. Importantly, only a small fraction of collagen fibers belonging to type III collagen admixture - a common component of a standard type I collagen preparation - accumulated plasma vWF and supported platelet adhesion at high shear rate. ConclusionType III, but not type I collagen fibers oriented parallel to the flow facilitate stable platelet adhesion at high shear rates. Thus, axial orientation of subendothelial collagen fibers observed in vivo may have physiological relevance for triggering rapid thrombus formation at high shear rates. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=106 SRC="FIGDIR/small/627297v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@14c1af5org.highwire.dtl.DTLVardef@17dffceorg.highwire.dtl.DTLVardef@12548d1org.highwire.dtl.DTLVardef@cfc431_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2022

Patterning Fluid Shear Stress Landscapes with Multiphoton Inner Laser Lithography (MILL) for Live Cell Adhesion and Translocation

Heterogenous fluid shear stress is known to provide mechanical cues for cell adhesion and translocation. To assemble 3D microstructures using current fabrication methods in a single channel and recapitulate in vivo heterogenous fluid flow would require hours of fabrication and specialized equipment. Inspired by the traditional art form of inside painting, we developed a technique for 3D fabrication of micro-patterned flow channels and mixed in vivo fluid flow in a matter of minutes. We termed this technique Multiphoton Inner Laser Lithography (MILL). We further showed that when combined with adaptive optics, MILL is compatible with both flat and curved channel shapes. MILL recapitulated in vivo tissue topology and 3D fluid flow within tissue stroma (low fluid shear, 0 - 3.5 dynes/cm2) and blood vessel (high fluid shear, 0 - 80 dynes/cm2). We demonstrate fibroblast cell and platelets adhere and translocate differently between laminar flow patterns that are homogenous versus heterogeneous in real time. Parallel strips of MILL channels were assembled for simultaneous platelet function test to quantify the efficacy of an antithrombotic GPVI Fab (~2000 microthrombi per test). The MILL technique can be readily reproduced in vivo fluid flow in minutes and benefit preclinical screening of drug pharmacokinetics. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=98 SRC="FIGDIR/small/496569v2_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1efbe9eorg.highwire.dtl.DTLVardef@cbab5aorg.highwire.dtl.DTLVardef@15ed255org.highwire.dtl.DTLVardef@42d14e_HPS_FORMAT_FIGEXP M_FIG C_FIG Significant pointsO_LIMILL channels are made from commercially available off the shelf components using a standard multiphoton imaging system C_LIO_LIVarying degrees of in vivo heterogenous laminar flow is shown to directly influence cells translocating on thinly coated collagen surfaces C_LIO_LIParallel strips of MILL channels were assembled for simultaneous platelet function tests (~2000 microthrombi per test). C_LI

bioengineering↗

bioRxiv2021

Analysis of microvascular thrombus mechanobiology with a novel particle-based model

Platelet accumulation at the site of vascular injury is regulated by soluble platelet agonists, which induce various types of platelet responses, including integrin activation and granule secretion. The interplay between local biochemical cues, mechanical interactions between platelets and macroscopic thrombus dynamics is poorly understood. Here we describe a novel computational model of microvascular thrombus formation for detailed analysis of thrombus mechanics. Adopting a previously developed two-dimensional particle-based model focused on the thrombus shell formation, we revise it to introduce platelet agonists. Blood flow is simulated via computational fluid dynamics approach. In order to model soluble platelet activators, we apply Langevin dynamics to a large number of non-dimensional virtual particles. Taking advantage of the available data on platelet dense granule secretion kinetics, we model platelet degranulation as a stochastic agonist-dependent process. The new model qualitatively reproduces enhanced thrombus formation due to granule secretion in line with in vivo findings and provides a mechanism for thrombin confinement at the early stages of aggregate formation. Our calculations also predict that release of dense granules results in additional mechanical stabilization of the inner layers of the thrombus. Distribution of the inter-platelet forces throughout the aggregate reveals multiple weak spots in the outer regions of thrombus, which are expected to result in mechanical disruptions at the later stages of thrombus formation.

biophysics↗