Biology subjects

Roy-Chaudhury, P.

Publications and source records attributed to Roy-Chaudhury, P..

3 recordsLinked to original sources

bioRxiv2026

Computational and Experimental Evaluation of a Flow-Conditioning Anastomotic Device for Arteriovenous Fistula Maturation

The arteriovenous fistula (AVF) is the preferred method of vascular access for hemodialysis; however, 30-50% of AVFs undergo primary failure and are unsuitable for clinical use. As disturbed hemodynamics initiate endothelial injury and intimal hyperplasia, we designed an endovascular flow-conditioning anastomotic device (FCAD) to directly improve AVF hemodynamics and protect the anastomotic region. Using computational fluid dynamics, we characterized the flow field and wall shear stress (WSS) profiles in idealized AVF models with and without the FCAD. Incorporation of the FCAD into a brachiocephalic AVF model reduced regions of oscillatory WSS and generated a symmetrical flow profile in the draining vein compared to a reference AVF. Parametric studies also identified an FCAD geometry with a tab angle, height, and aspect ratio of 30{degrees}, 0.1 diameters, and 1.0 restored time-averaged WSS along the inner venous wall, achieving a physiological level without inducing regions of oscillatory flow throughout the cardiac cycle. Similar findings were observed with an in vitro model using particle imaging velocimetry. This study demonstrates the feasibility of the FCAD to normalize venous flow and WSS while imposing minimal resistance to blood flow. Restoring physiological WSS levels on the venous wall is expected to preserve endothelial function and improve AVF maturation.

bioengineering↗

bioRxiv2025

Temporal evolution of hemodynamics in murine arteriovenous fistula: a micro-CT based computational fluid dynamics study

In this study, we investigated the hemodynamic characteristics of arteriovenous fistulae (AVF) in murine models using micro-CT based computational fluid dynamics (CFD). By combining high-resolution micro-CT imaging with ultrasound flow measurements, our methodology offers a cost-effective and efficient alternative to traditional MRI-based approaches. CFD simulations performed at 7 and 21 days post-surgery revealed significant temporal changes in both geometry and hemodynamics. Geometric analysis showed that: the proximal artery diameter increased from 0.29 mm to 0.38 mm, while the initial 2 mm fistula segment showed a 21.6% decrease (0.74 mm to 0.58 mm). Blood flow through the AVF nearly doubled from 1.33 mL/min to 2.57 mL/min. Time-averaged wall shear stress (TAWSS) peak values increased from 142 Pa (day 7) within the proximal artery to 200 Pa (day 21), in the stenotic region. The oscillatory shear index (OSI) showed marked elevation at the anastomosis (increasing from 0.22 to 0.48), indicating disturbed flow development. An inverse relationship between TAWSS and OSI was identified consistent with previous studies. Our methodology demonstrates the capability to analyze relationships between early hemodynamics and subsequent geometric changes. This approach could enable identification of regions susceptible to stenosis development and monitoring of AVF maturation, which could ultimately lead to quantitative metrics to evaluate surgical outcomes and early therapeutic interventions.

bioengineering↗

bioRxiv2024

Microphysiological uremia model reveals biophysical potentiators of vascular dysfunction

Cardiovascular disease is a leading cause of mortality in individuals with chronic kidney disease. Hypertension, common among patients with chronic kidney disease, is a major contributor to both kidney damage and the heightened cardiovascular risk in these patients. Advanced chronic kidney disease is associated with elevated levels of circulating uremic toxins, particularly indoxyl sulfate and p-cresyl sulfate, and are known to exacerbate cardiovascular risk by promoting inflammatory processes, including monocyte adhesion, rolling, and extravasation. However, despite the established link between chronic kidney disease and cardiovascular disease, the specific role of uremic toxins in monocyte-endothelial interactions in hypertensive settings remains largely underexplored. In this study, we developed a 3D microfluidic model to examine the effects of indoxyl sulfate on monocyte adhesion and extravasation across engineered microvessels embedded in collagen hydrogels with different densities under controlled luminal pressure. We found that elevated pressure alone significantly enhanced monocyte adhesion and extravasation, regardless of matrix density, and that the uremic environment further increased these effects. Additionally, denser hydrogels primed THP-1 monocyte cells toward a pro-inflammatory like phenotype with reduced phagocytic capacity, while softer hydrogels induced an anti-inflammatory like phenotype with enhanced phagocytosis. However, exposure to the uremic environment diminished phagocytosis and shifted cells toward a pro-inflammatory like state, irrespective of matrix density. The presented approach has the potential to experimentally dissect multiple factors that contribute to elevated cardiovascular risks in chronic kidney disease patients and improve the understanding of mechanisms involved in monocyte dynamics in chronic kidney disease- related cardiovascular disease.

bioengineering↗