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Liu Y, Feng X, Liu H, McComb DW, Breuer CK, Sacks MS. On the shape and structure of the murine pulmonary heart valve. Sci Rep 2021; 11:14078. [PMID: 34234231 PMCID: PMC8263753 DOI: 10.1038/s41598-021-93513-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 06/10/2021] [Indexed: 11/20/2022] Open
Abstract
Murine animal models are an established standard in translational research and provides a potential platform for studying heart valve disease. To date, studies on heart valve disease using murine models have been hindered by a lack of appropriate methodologies due to their small scale. In the present study, we developed a multi-scale, imaging-based approach to extract the functional structure and geometry for the murine heart valve. We chose the pulmonary valve (PV) to study, due to its importance in congenital heart valve disease. Excised pulmonary outflow tracts from eleven 1-year old C57BL/6J mice were fixed at 10, 20, and 30 mmHg to simulate physiological loading. Micro-computed tomography was used to reconstruct the 3D organ-level PV geometry, which was then spatially correlated with serial en-face scanning electron microscopy imaging to quantify local collagen fiber distributions. From the acquired volume renderings, we obtained the geometric descriptors of the murine PV under increasing transvalvular pressures, which demonstrated remarkable consistency. Results to date suggest that the preferred collagen orientation was predominantly in the circumferential direction, as in larger mammalian valves. The present study represents a first step in establishing organ-level murine models for the study of heart valve disease.
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Affiliation(s)
- Yifei Liu
- Center for Electron Microscopy and Analysis, The Ohio State University, Columbus, OH, 43210, USA
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Xinzeng Feng
- Willerson Center, Oden Institute for Computational Engineering and Sciences, The University of Texas At Austin, Austin, TX, 78712, USA
| | - Hao Liu
- Willerson Center, Oden Institute for Computational Engineering and Sciences, The University of Texas At Austin, Austin, TX, 78712, USA
- Department of Biomedical Engineering, The University of Texas At Austin, Austin, TX, 78712, USA
| | - David W McComb
- Center for Electron Microscopy and Analysis, The Ohio State University, Columbus, OH, 43210, USA
- Department of Materials Science and Engineering, The Ohio State University, Columbus, OH, 43210, USA
| | - Christopher K Breuer
- Center for Regenerative Medicine, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, 43205, USA
- Department of Pediatric Surgery, Nationwide Children's Hospital, Columbus, OH, 43205, USA
| | - Michael S Sacks
- Willerson Center, Oden Institute for Computational Engineering and Sciences, The University of Texas At Austin, Austin, TX, 78712, USA.
- Department of Biomedical Engineering, The University of Texas At Austin, Austin, TX, 78712, USA.
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Riemersma JC, Alsbach EJ, De Bruijn WC. Chemical aspects of glycogen contrast-staining by potassium osmate. THE HISTOCHEMICAL JOURNAL 1984; 16:123-36. [PMID: 6199328 DOI: 10.1007/bf01003544] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
To obtain contrast-staining of glycogen in electron microscopy, various contrast-enhancing additives can be used in combination with potassium osmate. Examples are potassium ferrocyanide and certain nitrogen heterocyclic compounds, such as triazoles. In the reaction sequence leading to contrast-stained glycogen, a primary reaction is the formation of glycogen osmate. This reaction was studied with isolated glycogen. On the basis of the stoichiometric findings, a molecular structure of the reaction product is proposed; apparently, osmate is bound by glycogen because of the presence of suitably located hydroxyl groups. The resulting compound is not itself sufficiently electron dense, but it binds 1,2,4-triazole as an additional ligand. Secondary reactions can result in additional osmium binding, and finally to osmium (IV) deposits, leading to contrast.
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de Bruijn WC, Memelink AA, Riemersma JC. Cellular membrane contrast and contrast differentiation with osmium triazole and tetrazole complexes. THE HISTOCHEMICAL JOURNAL 1984; 16:37-50. [PMID: 6200460 DOI: 10.1007/bf01003434] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Addition of heterocyclic nitrogen compounds to the classical osmium tetroxide postfixation medium, applied after glutaraldehyde fixation, results in enhanced membrane contrast in ultrathin sections of liver tissue. The addition of similar compounds to potassium osmate solutions, results in contrast differences in some cellular membranes. The membranes of the rough endoplasmic reticulum, the nuclear envelope and the plasma membrane acquire contrast, while the mitochondrial membranes do not. The apolar regions of membranes are contrasted when osmium tetroxide is combined with heterocyclic nitrogen compounds, whereas the polar regions are contrasted by combinations of potassium osmate with these compounds. This polar membrane contrast is probably due to the presence of an amino-group in the heterocyclic nitrogen compounds. Compounds without the amino-group do not contrast membranes, although the glycogen is contrasted. X-ray microanalysis served to establish the relative osmium content in contrasted glycogen, and showed that such nitrogen compounds play a role in complexation of cations in aldehyde-fixed tissues. Electron spectroscopy for chemical analysis (ESCA) measurements of isolated muscle glycogen show that after treatment with various osmium tetroxide or potassium osmate solutions, hexavalent and quadrivalent osmium species are present in the glycogen. The presence of (heterocyclic) nitrogen compounds in such solutions stabilizes certain osmium valency species, and this may account for the contrast observed.
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