1
|
Jirak D, Ziolkowska N, Turnovcova K, Karova K, Sykova E, Jendelova P, Romanyuk N. Metabolic Changes in Focal Brain Ischemia in Rats Treated With Human Induced Pluripotent Stem Cell-Derived Neural Precursors Confirm the Beneficial Effect of Transplanted Cells. Front Neurol 2019; 10:1074. [PMID: 31695666 PMCID: PMC6818685 DOI: 10.3389/fneur.2019.01074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 09/23/2019] [Indexed: 12/12/2022] Open
Abstract
There is currently no treatment for restoring lost neurological function after stroke. A growing number of studies have highlighted the potential of stem cells. However, the mechanisms underlying their beneficial effect have yet to be explored in sufficient detail. In this study, we transplanted human induced pluripotent stem cell-derived neural precursors (iPSC-NPs) in rat temporary middle cerebral artery occlusion (MCAO) model. Using magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) we monitored the effect of cells and assessed lesion volume and metabolite changes in the brain. We monitored concentration changes of myo-inositol (Ins), Taurine (Tau), Glycerophosphocholine+Phosphocholine (GPC+PCh), N-acetyl-aspartate+N-acetyl-aspartyl-glutamate (NAA+NAAG), Creatine+Phosphocreatine (Cr+PCr), and Glutamate+Glutamine (Glu+Gln) in the brains of control and iPSC-NP-transplanted rats. Based on initial lesion size, animals were divided into small lesion and big lesion groups. In the small lesion control group (SCL), lesion size after 4 months was three times smaller than initial measurements. In the small lesion iPSC-NP-treated group, lesion volume decreased after 1 month and then increased after 4 months. Although animals with small lesions significantly improved their motor skills after iPSC-NP transplantation, animals with big lesions showed no improvement. However, our MRI data demonstrate that in the big lesion iPSC-NP-treated (BTL) group, lesion size increased only up until 1 month after MCAO induction and then decreased. In contrast, in the big lesion control group, lesion size increased throughout the whole experiment. Significantly higher concentrations of Ins, Tau, GPC+PCh, NAA+NAAG, Cr+PCr, and Glu+Gln were found in in contralateral hemisphere in BTL animals 4 months after cell injection. Lesion volume decreased at this time point. Spectroscopic results of metabolite concentrations in lesion correlated with volumetric measurements of lesion, with the highest negative correlation observed for NAA+NAAG. Altogether, our results suggest that iPSC-NP transplantation decreases lesion volume and regulates metabolite concentrations within the normal range expected in healthy tissue. Further research into the ability of iPSC-NPs to differentiate into tissue-specific neurons and its effect on the long-term restoration of lesioned tissue is necessary.
Collapse
Affiliation(s)
- Daniel Jirak
- MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czechia.,First Faculty of Medicine, Institute of Biophysics and Informatics, Charles University, Prague, Czechia.,Faculty of Health Studies, Technical University of Liberec, Liberec, Czechia
| | - Natalia Ziolkowska
- MR Unit, Department of Diagnostic and Interventional Radiology, Institute for Clinical and Experimental Medicine, Prague, Czechia.,First Faculty of Medicine, Institute of Biophysics and Informatics, Charles University, Prague, Czechia
| | - Karolina Turnovcova
- Department of Neuroregeneration, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| | - Kristyna Karova
- Department of Neuroregeneration, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| | - Eva Sykova
- Department of Neuroscience, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| | - Pavla Jendelova
- Department of Neuroregeneration, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia.,Department of Neuroscience, Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Nataliya Romanyuk
- Department of Neuroregeneration, Institute of Experimental Medicine, Czech Academy of Sciences, Prague, Czechia
| |
Collapse
|
2
|
Mangia S, Liimatainen T, Garwood M, Tkac I, Henry PG, Deelchand D, Michaeli S. Frequency offset dependence of adiabatic rotating frame relaxation rate constants: relevance to MRS investigations of metabolite dynamics in vivo. NMR IN BIOMEDICINE 2011; 24:807-14. [PMID: 21264976 PMCID: PMC3121927 DOI: 10.1002/nbm.1626] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 07/16/2010] [Accepted: 09/21/2010] [Indexed: 05/24/2023]
Abstract
In this work, we investigated the frequency-offset dependence of the rotating frame longitudinal (R(1ρ)) and transverse (R(2ρ)) relaxation rate constants when using hyperbolic-secant adiabatic full passage pulses or continuous-wave spin-lock irradiation. Phantom and in vivo measurements were performed to validate theoretical predictions of the dominant relaxation mechanisms existing during adiabatic full passage pulses when using different settings of the frequency offset relative to the carrier. In addition, adiabatic R(1ρ) and R(2ρ) values of total creatine and N-acetylaspartate were measured in vivo from the human brain at 4 T. When the continuous-wave pulse power was limited to safe specific absorption rates for humans, simulations revealed a strong dependence of R(1ρ) and R(2ρ) values on the frequency offset for both dipolar interactions and anisochronous exchange mechanisms. By contrast, theoretical and experimental results showed adiabatic R(1ρ) and R(2ρ) values to be practically invariant within the large subregion of the bandwidth of the hyperbolic-secant pulse where complete inversion was achieved. However, adiabatic R(1ρ) and R(2ρ) values of the methyl protons of total creatine (at 3.03 ppm) were almost doubled when compared with those of the methyl protons of N-acetylaspartate (at 2.01 ppm) in spite of the fact that these resonances were in the flat region of the inversion band of the adiabatic full passage pulses. We conclude that differences in adiabatic R(1ρ) and R(2ρ) values of human brain metabolites are not a result of their chemical shifts, but instead reflect differences in dynamics.
Collapse
Affiliation(s)
- Silvia Mangia
- Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota School of Medicine, Minneapolis, MN 55455, USA.
| | | | | | | | | | | | | |
Collapse
|
3
|
Snyder J, Hanstock CC, Wilman AH. Spectral editing of weakly coupled spins using variable flip angles in PRESS constant echo time difference spectroscopy: application to GABA. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 200:245-250. [PMID: 19648038 DOI: 10.1016/j.jmr.2009.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 07/08/2009] [Accepted: 07/08/2009] [Indexed: 05/28/2023]
Abstract
A general in vivo magnetic resonance spectroscopy editing technique is presented to detect weakly coupled spin systems through subtraction, while preserving singlets through addition, and is applied to the specific brain metabolite gamma-aminobutyric acid (GABA) at 4.7 T. The new method uses double spin echo localization (PRESS) and is based on a constant echo time difference spectroscopy approach employing subtraction of two asymmetric echo timings, which is normally only applicable to strongly coupled spin systems. By utilizing flip angle reduction of one of the two refocusing pulses in the PRESS sequence, we demonstrate that this difference method may be extended to weakly coupled systems, thereby providing a very simple yet effective editing process. The difference method is first illustrated analytically using a simple two spin weakly coupled spin system. The technique was then demonstrated for the 3.01 ppm resonance of GABA, which is obscured by the strong singlet peak of creatine in vivo. Full numerical simulations, as well as phantom and in vivo experiments were performed. The difference method used two asymmetric PRESS timings with a constant total echo time of 131 ms and a reduced 120 degrees final pulse, providing 25% GABA yield upon subtraction compared to two short echo standard PRESS experiments. Phantom and in vivo results from human brain demonstrate efficacy of this method in agreement with numerical simulations.
Collapse
Affiliation(s)
- Jeff Snyder
- Department of Physics, University of Alberta, Edmonton, Alberta, Canada.
| | | | | |
Collapse
|