1
|
Epel B, Viswakarma N, Hameed S, Freidin MM, Abrams CK, Kotecha M. Assessment of blood-brain barrier leakage and brain oxygenation in Connexin-32 knockout mice with systemic neuroinflammation using pulse electron paramagnetic resonance imaging techniques. Magn Reson Med 2024; 91:2519-2531. [PMID: 38193348 PMCID: PMC10997480 DOI: 10.1002/mrm.29994] [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: 08/11/2023] [Revised: 11/30/2023] [Accepted: 12/13/2023] [Indexed: 01/10/2024]
Abstract
PURPOSE The determination of blood-brain barrier (BBB) integrity and partial pressure of oxygen (pO2) in the brain is of substantial interest in several neurological applications. This study aimed to assess the feasibility of using trityl OX071-based pulse electron paramagnetic resonance imaging (pEPRI) to provide a quantitative estimate of BBB integrity and pO2 maps in mouse brains as a function of neuroinflammatory disease progression. METHODS Five Connexin-32 (Cx32)-knockout (KO) mice were injected with lipopolysaccharide to induce neuroinflammation for imaging. Three wild-type mice were also used to optimize the imaging procedure and as control animals. An additional seven Cx32-KO mice were used to establish the BBB leakage of trityl using the colorimetric assay. All pEPRI experiments were performed using a preclinical instrument, JIVA-25 (25 mT/720 MHz), at times t = 0, 4, and 6 h following lipopolysaccharide injection. Two pEPRI imaging techniques were used: (a) single-point imaging for obtaining spatial maps to outline the brain and calculate BBB leakage using the signal amplitude, and (b) inversion-recovery electron spin echo for obtaining pO2 maps. RESULTS A statistically significant change in BBB leakage was found using pEPRI with the progression of inflammation in Cx32 KO animals. However, the change in pO2 values with the progression of inflammation for these animals was not statistically significant. CONCLUSIONS For the first time, we show the ability of pEPRI to provide pO2 maps in mouse brains noninvasively, along with a quantitative assessment of BBB leakage. We expect this study to open new queries from the field to explore the pathology of many neurological diseases and provide a path to new treatments.
Collapse
Affiliation(s)
- Boris Epel
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, Illinois, USA
- Department of Radiation and Cellular Oncology, The University of Chicago, Chicago, Illinois, USA
| | - Navin Viswakarma
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, Illinois, USA
| | - Safa Hameed
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, Illinois, USA
| | - Mona M Freidin
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Charles K Abrams
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, Illinois, USA
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | | |
Collapse
|
2
|
Shaw MA, Poncelet M, Viswakarma N, Vallerini GP, Hameed S, Gluth TD, Geldenhuys WJ, Hoblitzell EH, Eubank TD, Epel B, Kotecha M, Driesschaert B. SOX71, A Biocompatible Succinyl Derivative of the Triarylmethyl Radical OX071 for In Vivo Quantitative Oxygen Mapping Using Electron Paramagnetic Resonance. Mol Imaging Biol 2023:10.1007/s11307-023-01869-8. [PMID: 37945971 PMCID: PMC11078887 DOI: 10.1007/s11307-023-01869-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/27/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023]
Abstract
PURPOSE This study aimed to develop a biocompatible oximetric electron paramagnetic resonance (EPR) spin probe with reduced self-relaxation, and sensitivity to oxygen for a higher signal-to-noise ratio and longer relaxation times at high oxygen concentration, compared to the reference spin probe OX071. PROCEDURES SOX71 was synthesized by succinylation of the twelve alcohol groups of OX071 spin probe and characterized by EPR at X-Band (9.5 GHz) and at low field (720 MHz). The biocompatibility of SOX71 was tested in vitro and in vivo in mice. A pharmacokinetic study was performed to determine the best time frame for EPR imaging. Finally, a proof-of-concept EPR oxygen imaging was performed on a mouse model of a fibrosarcoma tumor. RESULTS SOX71 was synthesized in one step from OX071. SOX71 exhibits a narrow line EPR spectrum with a peak-to-peak linewidth of 66 mG, similar to OX071. SOX71 does not bind to albumin nor show cell toxicity for the concentrations tested up to 5 mM. No toxicity was observed after systemic delivery via intraperitoneal injection in mice at twice the dose required for EPR imaging. After the injection, the probe is readily absorbed into the bloodstream, with a peak blood concentration half an hour, post-injection. Then, the probe is quickly cleared by the kidney with a half-life of ~ 45 min. SOX71 shows long relaxation times under anoxic condition (T1e = 9.5 µs and T2e = 5.1 µs; [SOX71] = 1 mM in PBS at 37 °C, pO2 = 0 mmHg, 720 MHz). Both the relaxation rates R1e and R2e show a decreased sensitivity to pO2, leading to twice longer relaxation times under room air conditions (pO2 = 159 mmHg) compared to OX071. This is ideal for oxygen imaging in samples with a wide range of pO2. Both the relaxation rates R1e and R2e show a decreased sensitivity to self-relaxation compared to OX071, with a negligible effect of the probe concentration on R1e. SOX71 was successfully applied to image oxygen in a tumor. CONCLUSION SOX71, a succinylated derivative of OX071 was synthesized, characterized, and applied for in vivo EPR tumor oxygen imaging. SOX71 is highly biocompatible, and shows decreased sensitivity to oxygen and self-relaxation. This first report suggests that SOX71 is superior to OX071 for absolute oxygen mapping under a broad range of pO2 values.
Collapse
Affiliation(s)
- Misa A Shaw
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV, 26506, USA
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- West Virginia Clinical and Translational Sciences Institute, Morgantown, WV, 26506, USA
| | - Martin Poncelet
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV, 26506, USA
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
| | - Navin Viswakarma
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, IL, 60612, USA
| | | | - Safa Hameed
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, IL, 60612, USA
| | - Teresa D Gluth
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV, 26506, USA
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
| | - Werner J Geldenhuys
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV, 26506, USA
- Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Emily H Hoblitzell
- Department of Microbiology, Immunology, and Cell Biology, School of Medicine, West Virginia University, Morgantown, WV, 26506, USA
| | - Timothy D Eubank
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA
- West Virginia Clinical and Translational Sciences Institute, Morgantown, WV, 26506, USA
- Department of Microbiology, Immunology, and Cell Biology, School of Medicine, West Virginia University, Morgantown, WV, 26506, USA
- West Virginia University Cancer Institute, West Virginia University, Morgantown, WV, 26506, USA
| | - Boris Epel
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, 60637, USA
| | - Mrignayani Kotecha
- Oxygen Measurement Core, O2M Technologies, LLC, Chicago, IL, 60612, USA.
| | - Benoit Driesschaert
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV, 26506, USA.
- In Vivo Multifunctional Magnetic Resonance Center, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, 26506, USA.
- West Virginia Clinical and Translational Sciences Institute, Morgantown, WV, 26506, USA.
- Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, 26506, USA.
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, 60637, USA.
| |
Collapse
|