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Nelson MS, Liu Y, Wilson HM, Li B, Rosado-Mendez IM, Rogers JD, Block WF, Eliceiri KW. Multiscale Label-Free Imaging of Fibrillar Collagen in the Tumor Microenvironment. Methods Mol Biol 2023; 2614:187-235. [PMID: 36587127 DOI: 10.1007/978-1-0716-2914-7_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
With recent advances in cancer therapeutics, there is a great need for improved imaging methods for characterizing cancer onset and progression in a quantitative and actionable way. Collagen, the most abundant extracellular matrix protein in the tumor microenvironment (and the body in general), plays a multifaceted role, both hindering and promoting cancer invasion and progression. Collagen deposition can defend the tumor with immunosuppressive effects, while aligned collagen fiber structures can enable tumor cell migration, aiding invasion and metastasis. Given the complex role of collagen fiber organization and topology, imaging has been a tool of choice to characterize these changes on multiple spatial scales, from the organ and tumor scale to cellular and subcellular level. Macroscale density already aids in the detection and diagnosis of solid cancers, but progress is being made to integrate finer microscale features into the process. Here we review imaging modalities ranging from optical methods of second harmonic generation (SHG), polarized light microscopy (PLM), and optical coherence tomography (OCT) to the medical imaging approaches of ultrasound and magnetic resonance imaging (MRI). These methods have enabled scientists and clinicians to better understand the impact collagen structure has on the tumor environment, at both the bulk scale (density) and microscale (fibrillar structure) levels. We focus on imaging methods with the potential to both examine the collagen structure in as natural a state as possible and still be clinically amenable, with an emphasis on label-free strategies, exploiting intrinsic optical properties of collagen fibers.
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Affiliation(s)
- Michael S Nelson
- Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI, USA.,Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Yuming Liu
- Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI, USA
| | - Helen M Wilson
- Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI, USA.,Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Bin Li
- Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI, USA.,Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA.,Morgridge Institute for Research, Madison, WI, USA
| | - Ivan M Rosado-Mendez
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - Jeremy D Rogers
- Morgridge Institute for Research, Madison, WI, USA.,McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - Walter F Block
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA
| | - Kevin W Eliceiri
- Center for Quantitative Cell Imaging, University of Wisconsin-Madison, Madison, WI, USA. .,Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA. .,Morgridge Institute for Research, Madison, WI, USA. .,Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA. .,McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, USA.
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Deen SS, McLean MA, Gill AB, Crawford RAF, Latimer J, Baldwin P, Earl HM, Parkinson CA, Smith S, Hodgkin C, Jimenez-Linan M, Brodie CR, Patterson I, Addley HC, Freeman SJ, Moyle PM, Graves MJ, Sala E, Brenton JD, Gallagher FA. Magnetization transfer imaging of ovarian cancer: initial experiences of correlation with tissue cellularity and changes following neoadjuvant chemotherapy. BJR Open 2022; 4:20210078. [PMID: 36105417 PMCID: PMC9459873 DOI: 10.1259/bjro.20210078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 03/24/2022] [Accepted: 03/30/2022] [Indexed: 11/25/2022] Open
Abstract
Objectives To investigate the relationship between magnetization transfer (MT) imaging and tissue macromolecules in high-grade serous ovarian cancer (HGSOC) and whether MT ratio (MTR) changes following neoadjuvant chemotherapy (NACT). Methods This was a prospective observational study. 12 HGSOC patients were imaged before treatment. MTR was compared to quantified tissue histology and immunohistochemistry. For a subset of patients (n = 5), MT imaging was repeated after NACT. The Shapiro-Wilk test was used to assess for normality of data and Spearman's rank-order or Pearson's correlation tests were then used to compare MTR with tissue quantifications. The Wilcoxon signed-rank test was used to assess for changes in MTR after treatment. Results Treatment-naïve tumour MTR was 21.9 ± 3.1% (mean ± S.D.). MTR had a positive correlation with cellularity, rho = 0.56 (p < 0.05) and a negative correlation with tumour volume, ρ = -0.72 (p = 0.01). MTR did not correlate with the extracellular proteins, collagen IV or laminin (p = 0.40 and p = 0.90). For those patients imaged before and after NACT, an increase in MTR was observed in each case with mean MTR 20.6 ± 3.1% (median 21.1) pre-treatment and 25.6 ± 3.4% (median 26.5) post-treatment (p = 0.06). Conclusion In treatment-naïve HGSOC, MTR is associated with cellularity, possibly reflecting intracellular macromolecular concentration. MT may also detect the HGSOC response to NACT, however larger studies are required to validate this finding. Advances in knowledge MTR in HGSOC is influenced by cellularity. This may be applied to assess for cell changes following treatment.
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Affiliation(s)
| | | | - Andrew B Gill
- Department of Radiology, Box 218, University of Cambridge, Cambridge, United Kingdom, CB2 0QQ
| | - Robin A F Crawford
- Cambridge University Hospitals NHS Foundation Trust, Addenbrooke’s Hospital, Cambridge, United Kingdom, CB2 0QQ
| | - John Latimer
- Cambridge University Hospitals NHS Foundation Trust, Addenbrooke’s Hospital, Cambridge, United Kingdom, CB2 0QQ
| | - Peter Baldwin
- Cambridge University Hospitals NHS Foundation Trust, Addenbrooke’s Hospital, Cambridge, United Kingdom, CB2 0QQ
| | | | - Christine A Parkinson
- Cambridge University Hospitals NHS Foundation Trust, Addenbrooke’s Hospital, Cambridge, United Kingdom, CB2 0QQ
| | - Sarah Smith
- Cambridge University Hospitals NHS Foundation Trust, Addenbrooke’s Hospital, Cambridge, United Kingdom, CB2 0QQ
| | | | - Mercedes Jimenez-Linan
- Department of Pathology, Cambridge University Hospitals NHS Foundation Trust, Addenbrooke’s Hospital, Cambridge, United Kingdom, CB2 0QQ
| | - Cara R Brodie
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, United Kingdom, CB2 0RE
| | - Ilse Patterson
- Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Addenbrooke’s Hospital, Cambridge, United Kingdom, CB2 0QQ
| | - Helen C Addley
- Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Addenbrooke’s Hospital, Cambridge, United Kingdom, CB2 0QQ
| | - Susan J Freeman
- Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Addenbrooke’s Hospital, Cambridge, United Kingdom, CB2 0QQ
| | - Penelope M Moyle
- Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Addenbrooke’s Hospital, Cambridge, United Kingdom, CB2 0QQ
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Bimodal magnetic resonance and optical imaging of extracellular matrix remodelling by orthotopic ovarian tumours. Br J Cancer 2020; 123:216-225. [PMID: 32390007 PMCID: PMC7374547 DOI: 10.1038/s41416-020-0878-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 04/04/2020] [Accepted: 04/17/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The extracellular matrix modulates the development of ovarian tumours. Currently, evaluation of the extracellular matrix in the ovary is limited to histological methods. Both magnetic resonance imaging (MRI) and two-photon microscopy (2PM) enable dynamic visualisation and quantification of fibrosis by endogenous contrast mechanisms: magnetisation transfer (MT) MRI and second-harmonic generation (SHG) 2PM, respectively. METHODS Here, we applied the MT-MRI protocol for longitudinal imaging of the stroma in orthotopic human ovarian cancer ES-2 xenograft model in CD1 athymic nude mice, and for orthotopically implanted ovarian PDX using a MR-compatible imaging window chamber implanted into NSG mice. RESULTS We observed differences between ECM deposition in ovarian and skin lesions, and heterogeneous collagen distribution in ES-2 lesions. An MR-compatible imaging window chamber enabled visual matching between T2 MRI maps of orthotopically implanted PDX grafts and anatomical images of their microenvironment acquired with a stereomicroscope and SHG-2PM intravital microscopy of the collagen. Bimodal MRI/2PM imaging allowed us to quantify the fibrosis within the same compartments, and demonstrated the consistent results across the modalities. CONCLUSIONS This work demonstrates a novel approach for measuring the stromal biomarkers in orthotopic ovarian tumours in mice, on both macroscopic and microscopic levels.
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Cohn Yakubovich D, Eliav U, Yalon E, Schary Y, Sheyn D, Cook-Wiens G, Sun S, McKenna CE, Lev S, Binshtok AM, Pelled G, Navon G, Gazit D, Gazit Z. Teriparatide attenuates scarring around murine cranial bone allograft via modulation of angiogenesis. Bone 2017; 97:192-200. [PMID: 28119180 DOI: 10.1016/j.bone.2017.01.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 12/30/2016] [Accepted: 01/19/2017] [Indexed: 02/06/2023]
Abstract
Nearly all bone fractures in humans can deteriorate into a non-union fracture, often due to formation of fibrotic tissue. Cranial allogeneic bone grafts present a striking example: although seemingly attractive for craniofacial reconstructions, they often fail due to fibrosis at the host-graft junction, which physically prevents the desired bridging of bone between the host and graft and revitalization of the latter. In the present study we show that intermittent treatment with recombinant parathyroid hormone-analogue (teriparatide) modulates neovascularization feeding in the graft surroundings, consequently reducing fibrosis and scar tissue formation and facilitates osteogenesis. Longitudinal inspection of the vascular tree feeding the allograft has revealed that teriparatide induces formation of small-diameter vessels in the 1st week after surgery; by the 2nd week, abundant formation of small-diameter blood vessels was detected in untreated control animals, but far less in teriparatide-treated mice, although in total, more blood capillaries were detected in the animals that were given teriparatide. By that time point we observed expression of the profibrogenic mediator TGF-β in untreated animals, but negligible expression in the teriparatide-treated mice. To evaluate the formation of scar tissue, we utilized a magnetization transfer contrast MRI protocol to differentiate osteoid tissue from scar tissue, based on the characterization of collagen fibers. Using this method we found that significantly more bone matrix was formed in animals given teriparatide than in control animals. Altogether, our findings show how teriparatide diminishes scarring, ultimately leading to superior bone graft integration.
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Affiliation(s)
- Doron Cohn Yakubovich
- Skeletal Biotech Laboratory, Hebrew University-Hadassah Faculty of Dental Medicine, Jerusalem 91120, Israel
| | - Uzi Eliav
- School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Eran Yalon
- Skeletal Biotech Laboratory, Hebrew University-Hadassah Faculty of Dental Medicine, Jerusalem 91120, Israel
| | - Yeshai Schary
- Skeletal Biotech Laboratory, Hebrew University-Hadassah Faculty of Dental Medicine, Jerusalem 91120, Israel
| | - Dmitriy Sheyn
- Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Galen Cook-Wiens
- Biostatistics and Bioinformatics Research Center, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Shuting Sun
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, United States
| | - Charles E McKenna
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, United States
| | - Shaya Lev
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University, Jerusalem 91904, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University, Jerusalem 91904, Israel
| | - Alexander M Binshtok
- Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University, Jerusalem 91904, Israel; The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University, Jerusalem 91904, Israel
| | - Gadi Pelled
- Skeletal Biotech Laboratory, Hebrew University-Hadassah Faculty of Dental Medicine, Jerusalem 91120, Israel; Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Gil Navon
- School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
| | - Dan Gazit
- Skeletal Biotech Laboratory, Hebrew University-Hadassah Faculty of Dental Medicine, Jerusalem 91120, Israel; Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Zulma Gazit
- Skeletal Biotech Laboratory, Hebrew University-Hadassah Faculty of Dental Medicine, Jerusalem 91120, Israel; Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.
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Vandsburger M, Vandoorne K, Oren R, Leftin A, Mpofu S, Delli Castelli D, Aime S, Neeman M. Cardio-chemical exchange saturation transfer magnetic resonance imaging reveals molecular signatures of endogenous fibrosis and exogenous contrast media. Circ Cardiovasc Imaging 2014; 8:CIRCIMAGING.114.002180. [PMID: 25550399 DOI: 10.1161/circimaging.114.002180] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Application of emerging molecular MRI techniques, including chemical exchange saturation transfer (CEST)-MRI, to cardiac imaging is desirable; however, conventional methods are poorly suited for cardiac imaging, particularly in small animals with rapid heart rates. We developed a CEST-encoded steady state and retrospectively gated cardiac cine imaging sequence in which the presence of fibrosis or paraCEST contrast agents was directly encoded into the steady-state myocardial signal intensity (cardioCEST). METHODS AND RESULTS Development of cardioCEST: A CEST-encoded cardiac cine MRI sequence was implemented on a 9.4T small animal scanner. CardioCEST of fibrosis was serially performed by acquisition of a series of CEST-encoded cine images at multiple offset frequencies in mice (n=7) after surgically induced myocardial infarction. Scar formation was quantified using a spectral modeling approach and confirmed with histological staining. Separately, circulatory redistribution kinetics of the paramagnetic CEST agent Eu-HPDO3A were probed in mice using cardioCEST imaging, revealing rapid myocardial redistribution, and washout within 30 minutes (n=6). Manipulation of vascular tone resulted in heightened peak CEST contrast in the heart, but did not alter redistribution kinetics (n=6). At 28 days after myocardial infarction (n=3), CEST contrast kinetics in infarct zone tissue were altered, demonstrating gradual accumulation of Eu-HPDO3A in the increased extracellular space. CONCLUSIONS cardioCEST MRI enables in vivo imaging of myocardial fibrosis using endogenous contrast mechanisms, and of exogenously delivered paraCEST agents, and can enable multiplexed imaging of multiple molecular targets at high-resolution coupled with conventional cardiac MRI scans.
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Affiliation(s)
- Moriel Vandsburger
- From the Departments of Biological Regulation (M.V., K.V., R.O., S.M., M.N.) and Chemical Physics (A.L.), Weizmann Institute of Science, Rehovot, Israel; Department of Physiology and Biomedical Engineering, University of Kentucky, Lexington (M.V.); and Molecular Biotechnology Center, University of Torino, Torino, Italy (D.D.C., S.A.)
| | - Katrien Vandoorne
- From the Departments of Biological Regulation (M.V., K.V., R.O., S.M., M.N.) and Chemical Physics (A.L.), Weizmann Institute of Science, Rehovot, Israel; Department of Physiology and Biomedical Engineering, University of Kentucky, Lexington (M.V.); and Molecular Biotechnology Center, University of Torino, Torino, Italy (D.D.C., S.A.)
| | - Roni Oren
- From the Departments of Biological Regulation (M.V., K.V., R.O., S.M., M.N.) and Chemical Physics (A.L.), Weizmann Institute of Science, Rehovot, Israel; Department of Physiology and Biomedical Engineering, University of Kentucky, Lexington (M.V.); and Molecular Biotechnology Center, University of Torino, Torino, Italy (D.D.C., S.A.)
| | - Avigdor Leftin
- From the Departments of Biological Regulation (M.V., K.V., R.O., S.M., M.N.) and Chemical Physics (A.L.), Weizmann Institute of Science, Rehovot, Israel; Department of Physiology and Biomedical Engineering, University of Kentucky, Lexington (M.V.); and Molecular Biotechnology Center, University of Torino, Torino, Italy (D.D.C., S.A.)
| | - Senzeni Mpofu
- From the Departments of Biological Regulation (M.V., K.V., R.O., S.M., M.N.) and Chemical Physics (A.L.), Weizmann Institute of Science, Rehovot, Israel; Department of Physiology and Biomedical Engineering, University of Kentucky, Lexington (M.V.); and Molecular Biotechnology Center, University of Torino, Torino, Italy (D.D.C., S.A.)
| | - Daniela Delli Castelli
- From the Departments of Biological Regulation (M.V., K.V., R.O., S.M., M.N.) and Chemical Physics (A.L.), Weizmann Institute of Science, Rehovot, Israel; Department of Physiology and Biomedical Engineering, University of Kentucky, Lexington (M.V.); and Molecular Biotechnology Center, University of Torino, Torino, Italy (D.D.C., S.A.)
| | - Silvio Aime
- From the Departments of Biological Regulation (M.V., K.V., R.O., S.M., M.N.) and Chemical Physics (A.L.), Weizmann Institute of Science, Rehovot, Israel; Department of Physiology and Biomedical Engineering, University of Kentucky, Lexington (M.V.); and Molecular Biotechnology Center, University of Torino, Torino, Italy (D.D.C., S.A.)
| | - Michal Neeman
- From the Departments of Biological Regulation (M.V., K.V., R.O., S.M., M.N.) and Chemical Physics (A.L.), Weizmann Institute of Science, Rehovot, Israel; Department of Physiology and Biomedical Engineering, University of Kentucky, Lexington (M.V.); and Molecular Biotechnology Center, University of Torino, Torino, Italy (D.D.C., S.A.).
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Chan KWY, Liu G, van Zijl PCM, Bulte JWM, McMahon MT. Magnetization transfer contrast MRI for non-invasive assessment of innate and adaptive immune responses against alginate-encapsulated cells. Biomaterials 2014; 35:7811-8. [PMID: 24930848 DOI: 10.1016/j.biomaterials.2014.05.057] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 05/21/2014] [Indexed: 12/24/2022]
Abstract
By means of physical isolation of cells inside semi-permeable hydrogels, encapsulation has been widely used to immunoprotect transplanted cells. While spherical alginate microcapsules are now being used clinically, there still is little known about the patient's immune system response unless biopsies are obtained. We investigated the use of Magnetization Transfer (MT) imaging to non-invasively detect host immune responses against alginate capsules containing xenografted human hepatocytes in four groups of animals, including transplanted empty capsules (-Cells/-IS), capsules with live cells with (+LiveCells/+IS) and without immunosuppression (+LiveCells/-IS), and capsules with apoptotic cells in non-immunosuppressed animals (+DeadCells/-IS). The highest MT ratio (MTR) was found in +LiveCells/-IS, which increased from day 0 by 38% and 53% on days 7 and 14 after transplantation respectively, and corresponded to a distinctive increase in cell infiltration on histology. Furthermore, we show that macromolecular ratio maps based on MT data are more sensitive to cell infiltration and fibrosis than conventional MTR maps. Such maps showed a significant difference between +LiveCells/-IS (0.18 ± 0.02) and +DeadCells/-IS (0.13 ± 0.02) on day 7 (P < 0.01) existed, which was not observed on MTR imaging. We conclude that MT imaging, which is clinically available, can be applied for non-invasive monitoring of the occurrence of a host immune response against encapsulated cells.
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Affiliation(s)
- Kannie W Y Chan
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA; Center of Nanomedicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Baltimore, MD 21205, USA
| | - Guanshu Liu
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Peter C M van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Jeff W M Bulte
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Baltimore, MD 21205, USA
| | - Michael T McMahon
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD 21205, USA; Center of Nanomedicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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McGee MP, Morykwas M, Shelton J, Argenta L. Collagen unfolding accelerates water influx, determining hydration in the interstitial matrix. Biophys J 2012. [PMID: 23200049 DOI: 10.1016/j.bpj.2012.10.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
In the interstitial matrix, collagen unfolding at physiologic temperatures is thought to facilitate interactions with enzymes and scaffold molecules during inflammation, tissue remodeling, and wound healing. We tested the hypothesis that it also plays a role in modulating flows and matrix hydration potential. After progressively unfolding dermal collagen in situ, we measured the hydration parameters by osmotic stress techniques and modeled them as linear functions of unfolded collagen, quantified by differential scanning calorimetry after timed heat treatment. Consistent with the hypothetical model, the thermodynamic and flow parameters obtained experimentally were related linearly to the unfolded collagen fraction. The increases in relative humidity and intensity of T(2) maps were also consistent with interfacial energy contributions to the hydration potential and the hydrophobic character of the newly formed protein/water interfaces. As a plausible explanation, we propose that increased tension at interfaces formed during collagen unfolding generate local gradients in the matrix that accelerate water transfer in the dermis. This mechanism adds a convective component to interstitial transfer of biological fluids that, unlike diffusion, can speed the dispersion of water and large solutes within the matrix.
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Affiliation(s)
- Maria P McGee
- Plastic and Reconstructive Surgery Research, Wake-Forest University School of Medicine, Winston-Salem, NC, USA.
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Wang C, Witschey W, Goldberg A, Elliott M, Borthakur A, Reddy R. Magnetization transfer ratio mapping of intervertebral disc degeneration. Magn Reson Med 2011; 64:1520-8. [PMID: 20677229 DOI: 10.1002/mrm.22533] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The magnetization transfer ratio of the lumbar discs was spatially quantified from age-matched subjects and the nucleus pulposus magnetization transfer ratio was correlated with T2-weighted Pfirrmann grades. A moderate and significant linear correlation between magnetization transfer ratio and Pfirrmann grades was observed, suggesting that nucleus pulposus collagen relative density increases with degeneration. High-resolution axial magnetization transfer ratio maps revealed elevated magnetization transfer ratio in the nucleus pulposa of injured and heavily degenerated discs. In the injured disc, significant elevation in nucleus pulposa magnetization transfer ratio was not accompanied by significant decrease in disc height. This observation may suggest a possible increase in absolute collagen content, in addition to increased collagen relative density. In summary, magnetization transfer MRI of the disc may serve as a noninvasive diagnostic tool for disc degeneration, in addition to other MRI techniques specific to proteoglycan content.
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Affiliation(s)
- Chenyang Wang
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6100, USA.
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Pérez-Torres CJ, Massaad CA, Hilsenbeck SG, Serrano F, Pautler RG. In vitro and in vivo magnetic resonance imaging (MRI) detection of GFP through magnetization transfer contrast (MTC). Neuroimage 2010; 50:375-82. [PMID: 20060482 DOI: 10.1016/j.neuroimage.2009.12.111] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 12/02/2009] [Accepted: 12/27/2009] [Indexed: 11/17/2022] Open
Abstract
Green fluorescent protein (GFP) is a widely utilized molecular marker of gene expression. However, its use in in vivo imaging has been restricted to transparent tissue mainly due to the tissue penetrance limitation of optical imaging. Here, we report a novel approach to detect GFP with Magnetization transfer contrast (MTC) magnetic resonance imaging (MRI). MTC is an MRI methodology currently utilized to detect macromolecule changes such as decrease in myelin and increase in collagen content. We employed MTC MRI imaging to detect GFP both in vitro and in in vivo mouse models. We demonstrated that our approach produces values that are protein specific, and concentration dependent. This approach provides a flexible, non-invasive in vivo molecular MRI imaging strategy that is dependent upon the presence and concentration of the GFP reporter.
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Affiliation(s)
- Carlos J Pérez-Torres
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX 77030, USA
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