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Qi Y, Chang SS, Wang Y, Chen C, Baek KI, Hsiai T, Roper M. Hemodynamic regulation allows stable growth of microvascular networks. Proc Natl Acad Sci U S A 2024; 121:e2310993121. [PMID: 38386707 PMCID: PMC10907248 DOI: 10.1073/pnas.2310993121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 01/16/2024] [Indexed: 02/24/2024] Open
Abstract
How do vessels find optimal radii? Capillaries are known to adapt their radii to maintain the shear stress of blood flow at the vessel wall at a set point, yet models of adaptation purely based on average shear stress have not been able to produce complex loopy networks that resemble real microvascular systems. For narrow vessels where red blood cells travel in a single file, the shear stress on vessel endothelium peaks sharply when a red blood cell passes through. We show that stable shear-stress-based adaptation is possible if vessel shear stress set points are cued to the stress peaks. Model networks that respond to peak stresses alone can quantitatively reproduce the observed zebrafish trunk microcirculation, including its adaptive trajectory when hematocrit changes or parts of the network are amputated. Our work reveals the potential for mechanotransduction alone to generate stable hydraulically tuned microvascular networks.
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Affiliation(s)
- Yujia Qi
- Department of Mechanical Engineering, University of California, Los Angeles, CA90095
| | - Shyr-Shea Chang
- Department of Mathematics, University of California, Los Angeles, CA90095
| | - Yixuan Wang
- Department of Mathematics, University of California, Los Angeles, CA90095
| | - Cynthia Chen
- Department of Bioengineering, University of California, Los Angeles, CA90095
| | - Kyung In Baek
- Department of Bioengineering, University of California, Los Angeles, CA90095
| | - Tzung Hsiai
- Department of Bioengineering, University of California, Los Angeles, CA90095
| | - Marcus Roper
- Department of Mathematics, University of California, Los Angeles, CA90095
- Department of Computational Medicine, University of California, Los Angeles, CA90095
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Maung Ye SS, Phng LK. A cell-and-plasma numerical model reveals hemodynamic stress and flow adaptation in zebrafish microvessels after morphological alteration. PLoS Comput Biol 2023; 19:e1011665. [PMID: 38048371 PMCID: PMC10721208 DOI: 10.1371/journal.pcbi.1011665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 12/14/2023] [Accepted: 11/06/2023] [Indexed: 12/06/2023] Open
Abstract
The development of a functional cardiovascular system ensures a sustainable oxygen, nutrient and hormone delivery system for successful embryonic development and homeostasis in adulthood. While early vessels are formed by biochemical signaling and genetic programming, the onset of blood flow provides mechanical cues that participate in vascular remodeling of the embryonic vascular system. The zebrafish is a prolific animal model for studying the quantitative relationship between blood flow and vascular morphogenesis due to a combination of favorable factors including blood flow visualization in optically transparent larvae. In this study, we have developed a cell-and-plasma blood transport model using computational fluid dynamics (CFD) to understand how red blood cell (RBC) partitioning affect lumen wall shear stress (WSS) and blood pressure in zebrafish trunk blood vascular networks with altered rheology and morphology. By performing live imaging of embryos with reduced hematocrit, we discovered that cardiac output and caudal artery flow rates were maintained. These adaptation trends were recapitulated in our CFD models, which showed reduction in network WSS via viscosity reduction in the caudal artery/vein and via pressure gradient weakening in the intersegmental vessels (ISVs). Embryos with experimentally reduced lumen diameter showed reduced cardiac output and caudal artery flow rate. Factoring in this trend into our CFD models, simulations highlighted that lumen diameter reduction increased vessel WSS but this increase was mitigated by flow reduction due to the adaptive network pressure gradient weakening. Additionally, hypothetical network CFD models with different vessel lumen diameter distribution characteristics indicated the significance of axial variation in lumen diameter and cross-sectional shape for establishing physiological WSS gradients along ISVs. In summary, our work demonstrates how both experiment-driven and hypothetical CFD modeling can be employed for the study of blood flow physiology during vascular remodeling.
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Affiliation(s)
- Swe Soe Maung Ye
- Laboratory for Vascular Morphogenesis, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Li-Kun Phng
- Laboratory for Vascular Morphogenesis, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
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Gonzalez-Ramos S, Wang J, Cho JM, Zhu E, Park SK, In JG, Reddy ST, Castillo EF, Campen MJ, Hsiai TK. Integrating 4-D light-sheet fluorescence microscopy and genetic zebrafish system to investigate ambient pollutants-mediated toxicity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 902:165947. [PMID: 37543337 PMCID: PMC10659062 DOI: 10.1016/j.scitotenv.2023.165947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 08/07/2023]
Abstract
Ambient air pollutants, including PM2.5 (aerodynamic diameter d ~2.5 μm), PM10 (d ~10 μm), and ultrafine particles (UFP: d < 0.1 μm) impart both short- and long-term toxicity to various organs, including cardiopulmonary, central nervous, and gastrointestinal systems. While rodents have been the principal animal model to elucidate air pollution-mediated organ dysfunction, zebrafish (Danio rerio) is genetically tractable for its short husbandry and life cycle to study ambient pollutants. Its electrocardiogram (ECG) resembles that of humans, and the fluorescent reporter-labeled tissues in the zebrafish system allow for screening a host of ambient pollutants that impair cardiovascular development, organ regeneration, and gut-vascular barriers. In parallel, the high spatiotemporal resolution of light-sheet fluorescence microscopy (LSFM) enables investigators to take advantage of the transparent zebrafish embryos and genetically labeled fluorescent reporters for imaging the dynamic cardiac structure and function at a single-cell resolution. In this context, our review highlights the integrated strengths of the genetic zebrafish system and LSFM for high-resolution and high-throughput investigation of ambient pollutants-mediated cardiac and intestinal toxicity.
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Affiliation(s)
- Sheila Gonzalez-Ramos
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA; Department of Bioengineering, School of Engineering & Applied Science, University of California, Los Angeles, CA, USA
| | - Jing Wang
- Department of Bioengineering, School of Engineering & Applied Science, University of California, Los Angeles, CA, USA
| | - Jae Min Cho
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
| | - Enbo Zhu
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
| | - Seul-Ki Park
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA
| | - Julie G In
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Srinivasa T Reddy
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA; Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA, USA; Molecular Toxicology Interdepartmental Degree Program, Fielding School of Public Health, University of California, Los Angeles, CA, USA
| | - Eliseo F Castillo
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Matthew J Campen
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Tzung K Hsiai
- Division of Cardiology, Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, USA; Department of Bioengineering, School of Engineering & Applied Science, University of California, Los Angeles, CA, USA; Greater Los Angeles VA Healthcare System, Department of Medicine, Los Angeles, California, USA.
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Huang XH, Zheng LQ, Dai YX, Hu SN, Ning WC, Li SM, Fan YG, Lin ZL, Huang SH. Combined computational analysis and cytology show limited depth osteogenic effect on bone defects in negative pressure wound therapy. Front Bioeng Biotechnol 2023; 11:1056707. [PMID: 36873351 PMCID: PMC9978480 DOI: 10.3389/fbioe.2023.1056707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 02/09/2023] [Indexed: 02/18/2023] Open
Abstract
Background: The treatment of bone defects remains a clinical challenge. The effect of negative pressure wound therapy (NPWT) on osteogenesis in bone defects has been recognized; however, bone marrow fluid dynamics under negative pressure (NP) remain unknown. In this study, we aimed to examine the marrow fluid mechanics within trabeculae by computational fluid dynamics (CFD), and to verify osteogenic gene expression, osteogenic differentiation to investigate the osteogenic depth under NP. Methods: The human femoral head is scanned using micro-CT to segment the volume of interest (VOI) trabeculae. The VOI trabeculae CFD model simulating the bone marrow cavity is developed by combining the Hypermesh and ANSYS software. The effect of trabecular anisotropy is investigated, and bone regeneration effects are simulated under NP scales of -80, -120, -160, and -200 mmHg. The working distance (WD) is proposed to describe the suction depth of the NP. Finally, gene sequence analysis, cytological experiments including bone mesenchymal stem cells (BMSCs) proliferation and osteogenic differentiation are conducted after the BMSCs are cultured under the same NP scale. Results: The pressure, shear stress on trabeculae, and marrow fluid velocity decrease exponentially with an increase in WD. The hydromechanics of fluid at any WD inside the marrow cavity can be theoretically quantified. The NP scale significantly affects the fluid properties, especially those fluid close to the NP source; however, the effect of the NP scale become marginal as WD deepens. Anisotropy of trabecular structure coupled with the anisotropic hydrodynamic behavior of bone marrow; An NP of -120 mmHg demonstrates the majority of bone formation-related genes, as well as the most effective proliferation and osteogenic differentiation of BMSCs compared to the other NP scales. Conclusion: An NP of -120 mmHg may have the optimal activated ability to promote osteogenesis, but the effective WD may be limited to a certain depth. These findings help improve the understanding of fluid mechanisms behind NPWT in treating bone defects.
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Affiliation(s)
- Xiu-Hong Huang
- School of Stomatology, Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Li-Qin Zheng
- The First Clinical Medical College, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yue-Xing Dai
- The First Clinical Medical College, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Shao-Nan Hu
- School of Stomatology, Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Wan-Chen Ning
- School of Stomatology, Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Si-Min Li
- School of Stomatology, Stomatological Hospital, Southern Medical University, Guangzhou, China
| | - Yue-Guang Fan
- Department of Joint Surgery, First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zi-Ling Lin
- Department of Orthopedic Trauma, First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Shao-Hong Huang
- School of Stomatology, Stomatological Hospital, Southern Medical University, Guangzhou, China
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Maung Ye SS, Kim JK, Carretero NT, Phng LK. High-Throughput Imaging of Blood Flow Reveals Developmental Changes in Distribution Patterns of Hemodynamic Quantities in Developing Zebrafish. Front Physiol 2022; 13:881929. [PMID: 35795647 PMCID: PMC9251365 DOI: 10.3389/fphys.2022.881929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
Mechanical forces from blood flow and pressure (hemodynamic forces) contribute to the formation and shaping of the blood vascular network during embryonic development. Previous studies have demonstrated that hemodynamic forces regulate signaling and gene expression in endothelial cells that line the inner surface of vascular tubes, thereby modifying their cellular state and behavior. Given its important role in vascular development, we still know very little about the quantitative aspects of hemodynamics that endothelial cells experience due to the difficulty in measuring forces in vivo. In this study, we sought to determine the magnitude of wall shear stress (WSS) exerted on ECs by blood flow in different vessel types and how it evolves during development. Utilizing the zebrafish as a vertebrate model system, we have established a semi-automated high-throughput fluorescent imaging system to capture the flow of red blood cells in an entire zebrafish between 2- and 6-day post-fertilization (dpf). This system is capable of imaging up to 50 zebrafish at a time. A semi-automated analysis method was developed to calculate WSS in zebrafish trunk vessels. This was achieved by measuring red blood cell flow using particle tracking velocimetry analysis, generating a custom-made script to measure lumen diameter, and measuring local tube hematocrit levels to calculate the effective blood viscosity at each developmental stage. With this methodology, we were able to determine WSS magnitude in different vessels at different stages of embryonic and larvae growth and identified developmental changes in WSS, with absolute levels of peak WSS in all vessel types falling to levels below 0.3 Pa at 6 dpf. Additionally, we discovered that zebrafish display an anterior-to-posterior trend in WSS at each developmental stage.
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Affiliation(s)
- Swe Soe Maung Ye
- Laboratory for Vascular Morphogenesis, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Jung Kyung Kim
- Laboratory for Vascular Morphogenesis, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
- School of Mechanical Engineering, Kookmin University, Seoul, South Korea
| | - Nuria Taberner Carretero
- Laboratory for Vascular Morphogenesis, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Li-Kun Phng
- Laboratory for Vascular Morphogenesis, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
- *Correspondence: Li-Kun Phng,
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