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Xu Y, Ward AD, Goldman D, Yin H, Arpino JM, Nong Z, Lee JJ, O'Neil C, Pickering JG. Arteriolar dysgenesis in ischemic, regenerating skeletal muscle revealed by automated micro-morphometry, computational modeling, and perfusion analysis. Am J Physiol Heart Circ Physiol 2022; 323:H38-H48. [PMID: 35522554 DOI: 10.1152/ajpheart.00010.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Rebuilding the local vasculature is central to restoring the health of muscles subjected to ischemic injury. Arteriogenesis yields remodeled collateral arteries that circumvent the obstruction, and angiogenesis produces capillaries to perfuse the regenerating myofibers. However, the vital intervening network of arterioles that feed the regenerated capillaries is poorly understood and an investigative challenge. We used machine learning and automated micro-morphometry to quantify the arteriolar landscape in distal hindlimb muscles in mice that have regenerated after femoral artery excision. Assessment of 1546 arteriolar sections revealed a striking (> 2-fold) increase in arteriolar density in regenerated muscle 14 and 28 days after ischemic injury. Lumen caliber was initially similar to that of control arterioles but after 4 weeks lumen area was reduced by 46%. In addition, the critical smooth muscle layer was attenuated throughout the arteriolar network, across a 150 to 5 µm diameter range. To understand the consequences of the reshaped distal hindlimb arterioles, we undertook computational flow modeling which revealed blunted flow augmentation. Moreover, impaired flow reserve was confirmed in vivo by laser Doppler analyses of flow in response to directly applied sodium nitroprusside. Thus, in hindlimb muscles regenerating after ischemic injury, the arteriolar network is amplified, inwardly remodels, and is diffusely under-muscularized. These defects and the associated flow restraints could contribute to the deleterious course of peripheral artery disease and merit attention when considering therapeutic innovations.
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Affiliation(s)
- Yiwen Xu
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada
| | - Aaron D Ward
- Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada
| | - Daniel Goldman
- Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada
| | - Hao Yin
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - John-Michael Arpino
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada
| | - Zengxuan Nong
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - Jason J Lee
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada.,Department of Medicine, University of Western Ontario, London, Ontario, Canada
| | - Caroline O'Neil
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada
| | - J Geoffrey Pickering
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.,Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada.,Department of Biochemistry, University of Western Ontario, London, Ontario, Canada.,Department of Medicine, University of Western Ontario, London, Ontario, Canada
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Yin H, Arpino JM, Lee JJ, Pickering JG. Regenerated Microvascular Networks in Ischemic Skeletal Muscle. Front Physiol 2021; 12:662073. [PMID: 34177614 PMCID: PMC8231913 DOI: 10.3389/fphys.2021.662073] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 05/10/2021] [Indexed: 12/24/2022] Open
Abstract
Skeletal muscle is the largest organ in humans. The viability and performance of this metabolically demanding organ are exquisitely dependent on the integrity of its microcirculation. The architectural and functional attributes of the skeletal muscle microvasculature are acquired during embryonic and early postnatal development. However, peripheral vascular disease in the adult can damage the distal microvasculature, together with damaging the skeletal myofibers. Importantly, adult skeletal muscle has the capacity to regenerate. Understanding the extent to which the microvascular network also reforms, and acquires structural and functional competence, will thus be critical to regenerative medicine efforts for those with peripheral artery disease (PAD). Herein, we discuss recent advances in studying the regenerating microvasculature in the mouse hindlimb following severe ischemic injury. We highlight new insights arising from real-time imaging of the microcirculation. This includes identifying otherwise hidden flaws in both network microarchitecture and function, deficiencies that could underlie the progressive nature of PAD and its refractoriness to therapy. Recognizing and overcoming these vulnerabilities in regenerative angiogenesis will be important for advancing treatment options for PAD.
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Affiliation(s)
- Hao Yin
- Robarts Research Institute, Western University, London, ON, Canada
| | | | - Jason J Lee
- Robarts Research Institute, Western University, London, ON, Canada.,Department of Medicine, Western University, London, ON, Canada
| | - J Geoffrey Pickering
- Robarts Research Institute, Western University, London, ON, Canada.,Department of Medicine, Western University, London, ON, Canada.,Department of Medical Biophysics, Western University, London, ON, Canada.,Department of Biochemistry, Western University, London, ON, Canada
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3D vessel-wall virtual histology of whole-body perfused mice using a novel heavy element stain. Sci Rep 2019; 9:698. [PMID: 30679558 PMCID: PMC6345940 DOI: 10.1038/s41598-018-36905-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 11/23/2018] [Indexed: 01/17/2023] Open
Abstract
Virtual histology – utilizing high-resolution three-dimensional imaging – is becoming readily available. Micro-computed tomography (micro-CT) is widely available and is often coupled with x-ray attenuating histological stains that mark specific tissue components for 3D virtual histology. In this study we describe a new tri-element x-ray attenuating stain and perfusion protocol that provides micro-CT contrast of the entire vasculature of an intact mouse. The stain – derived from an established histology stain (Verhoeff’s) – is modified to enable perfusion through the vasculature; the attenuating elements of the stain are iodine, aluminum, and iron. After a 30-minute perfusion through the vasculature (10-minute flushing with detergent-containing saline followed by 15-minute perfusion with the stain and a final 5-minute saline flush), animals are scanned using micro-CT. We demonstrate that the new staining protocol enables sharp delineation of the vessel walls in three dimensions over the whole body; corresponding histological analysis verified that the CT stain is localized primarily in the endothelial cells and media of large arteries and the endothelium of smaller vessels, such as the coronaries. The rapid perfusion and scanning protocol ensured that all tissues are available for further analysis via higher resolution CT of smaller sections or traditional histological sectioning.
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