Biology subjects

Sudo, R.

Publications and source records attributed to Sudo, R..

3 recordsLinked to original sources

bioRxiv2025

Paracrine Factor Local Gradient-Generating System for Engineering Perfusable Vascularized Hepatocyte Tissues with Perfusion-Induced Proliferation

Donor organ shortages drive the urgent need for engineered hepatocyte tissues, yet functional vascular integration remains a major bottleneck in liver tissue engineering. Current vascularization strategies struggle to achieve perfusable microvessels that penetrate hepatocyte tissue. Furthermore, in vitro recapitulation of hepatic regeneration remains a major challenge. This study presents a paracrine factor local gradient (PFLG)-generating system that constructs vascularized, perfusable hepatocyte tissues and recapitulates the perfusion-mediated proliferative capacity of primary hepatocytes. The PFLG-generating platform integrates fibroblast-loaded cryogels with a microfluidic device to direct angiogenesis prior to hepatocyte seeding, thereby enabling microvessels to penetrate three-dimensional hepatocyte tissue. Within the vascularized constructs, microvessels directly penetrated the hepatocyte parenchyma, recapitulating intimate hepatocyte-microvessel contact in vivo. These constructs enhanced hepatocyte polarity and functional bile canaliculi. Importantly, under perfusion culture, robust hepatocyte proliferation was induced, with Ki67-positive hepatocytes increasing significantly, including mitotic cells while preserving polarity. By contrast, this proliferative response was minimal under static conditions. Time-lapse imaging and functional assays confirmed perfusion through penetrating microvessels. These findings demonstrate that perfusion-mediated cues are essential for inducing hepatocyte proliferation while maintaining functional polarity. This modular and programmable culture platform lays the foundation for scale-up toward transplantable liver tissues.

bioengineering↗

bioRxiv2025

Flow-driven construction of capillary-scale vessels with predefined geometries in natural hydrogels

Forming capillary networks with predefined geometries is a critical challenge in engineering complex three-dimensional tissues in vitro. While bioprinting and microfluidic technologies have enabled vascular tissue fabrication, precise control over capillary-scale vascularization remains limited. In this study, we investigated vascular formation process along hydrogel microchannels to elucidate mechanisms governing capillary-scale lumen formation. Microchannels were fabricated by femtosecond laser ablation in collagen and fibrin hydrogels. We optimized multiphoton lithography parameters to fabricate microchannels within these hydrogels and analyzed vascular formation along the channels. Luminal vascular structures formed readily in 50-m channels, while vascular formation failed in 20-m channels under static conditions, suggesting a significant shift in endothelial organization at the cellular scale. Flow stimulation significantly promoted vessel formation through collective endothelial cell migration and adhesion, whereas static conditions induced endothelial-to-mesenchymal transition. These findings provide key insights into capillary-scale vascularization and contribute to the development of more complex architectures with predefined shapes.

bioengineering↗

bioRxiv2023

Multicellular dynamics on 3D scaffolds: Stress concentration is a key to controlling complex microtissue morphology on engineered surfaces

Tissue engineers have utilized a variety of three-dimensional (3D) scaffolds for controlling multicellular dynamics and the resulting tissue microstructures. In particular, cutting-edge microfabrication technologies, such as 3D bioprinting, provide increasingly complex structures. However, unpredictable microtissue detachment from scaffolds, which ruins desired tissue structures, is becoming an evident problem. To overcome this issue, we elucidated the mechanism underlying collective cellular detachment by combining a new computational simulation method with quantitative tissue-culture experiments. We first quantified the stochastic processes of cellular detachment shown by vascular smooth muscle cells on model curved scaffolds and found that microtissue morphologies vary drastically depending on cell contractility, substrate curvature, and cell-substrate adhesion strength. To explore this mechanism, we developed a new particle-based model that explicitly describes stochastic processes of multicellular dynamics, such as adhesion, rupture, and large deformation of microtissues on structured surfaces. Computational simulations using the developed model successfully reproduced characteristic detachment processes observed in experiments. Crucially, simulations revealed that cellular contractility-induced stress is locally concentrated at the cell-substrate interface, subsequently inducing a catastrophic process of collective cellular detachment, which can be suppressed by modulating cell contractility, substrate curvature, and cell-substrate adhesion. These results show that the developed computational method is useful for predicting engineered tissue dynamics as a platform for prediction-guided scaffold design.

biophysics↗