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- Kaya, Ibrahim, et al.
(författare)
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Multimodal MALDI Imaging Mass Spectrometry Reveals Spatially Correlated Lipid and Protein Changes in Mouse Heart with Acute Myocardial Infarction
- 2020
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Ingår i: Journal of the American Society for Mass Spectrometry. - : American Chemical Society (ACS). - 1044-0305 .- 1879-1123. ; 31:10, s. 2133-2142
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Tidskriftsartikel (refereegranskat)abstract
- Acute myocardial infarction (MI) is a cardiovascular disease that remains a major cause of morbidity and mortality worldwide despite advances in its prevention and treatment. During acute myocardial ischemia, the lack of oxygen switches the cell metabolism to anaerobic respiration, with lactate accumulation, ATP depletion, Na+ and Ca2+ overload, and inhibition of myocardial contractile function, which drastically modifies the lipid, protein, and small metabolite profile in the myocardium. Imaging mass spectrometry (IMS) is a powerful technique to comprehensively elucidate the spatial distribution patterns of lipids, peptides, and proteins in biological tissue sections. In this work, we demonstrate an application of multimodal chemical imaging using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), which provided comprehensive molecular information in situ within the same mouse heart tissue sections with myocardial infarction. MALDI-IMS (at 30 mu m per pixel) revealed infarct-associated spatial alterations of several lipid species of sphingolipids, glycerophospholipids, lysophospholipids, and cardiolipins along with the acyl carnitines. Further, we performed multimodal MALDI-IMS (IMS3) where dual polarity lipid imaging was combined with subsequent protein MALDI-IMS analysis (at 30 mu m per pixel) within the same tissue sections, which revealed accumulations of core histone proteins H4, H2A, and H2B along with post-translational modification products, acetylated H4 and H2A, on the borders of the infarcted region. This methodology allowed us to interpret the lipid and protein molecular pathology of the very same infarcted region in a mouse model of myocardial infarction. Therefore, the presented data highlight the potential of multimodal MALDI imaging mass spectrometry of the same tissue sections as a powerful approach for simultaneous investigation of spatial infarct-associated lipid and protein changes of myocardial infarction.
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| 2. |
- Sämfors, Sanna, 1987, et al.
(författare)
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Lipid Diversity in Cells and Tissue Using Imaging SIMS
- 2020
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Ingår i: Annual Review of Analytical Chemistry. - : Annual Reviews. - 1936-1327 .- 1936-1335. ; 13:1, s. 249-271
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Tidskriftsartikel (refereegranskat)abstract
- Lipids are an important class of biomolecules with many roles within cells and tissue. As targets for study, they present several challenges. They are difficult to label, as many labels lack the specificity to the many different lipid species or the labels maybe larger than the lipids themselves, thus severely perturbing the natural chemical environment. Mass spectrometry provides exceptional specificity and is often used to examine lipid extracts from different samples. However, spatial information is lost during extraction. Of the different imaging mass spectrometry methods available, secondary ion mass spectrometry (SIMS) is unique in its ability to analyze very small features, with probe sizes <50 nm available. It also offers high surface sensitivity and 3D imaging capability on a subcellular scale. This article reviews the current capabilities and some remaining challenges associated with imaging the diverse lipids present in cell and tissue samples. We show how the technique has moved beyond show-and-tell, proof-of-principle analysis and is now being used to address real biological challenges. These include imaging the microenvironment of cancer tumors, probing the pathophysiology of traumatic brain injury, or tracking the lipid composition through bacterial membranes. © 2020 by Annual Reviews. All rights reserved.
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| 3. |
- van Zyl, Martin, et al.
(författare)
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Injectable conductive hydrogel restores conduction through ablated myocardium
- 2020
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Ingår i: Journal of Cardiovascular Electrophysiology. - : Wiley. - 1045-3873 .- 1540-8167. ; 31:12, s. 3293-3301
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Therapies for substrate-related arrhythmias include ablation or drugs targeted at altering conductive properties or disruption of slow zones in heterogeneous myocardium. Conductive compounds such as carbon nanotubes may provide a novel personalizable therapy for arrhythmia treatment by allowing tissue homogenization. Methods A nanocellulose carbon nanotube-conductive hydrogel was developed to have conduction properties similar to normal myocardium. Ex vivo perfused canine hearts were studied. Electroanatomic activation mapping of the epicardial surface was performed at baseline, after radiofrequency ablation, and after uniform needle injections of the conductive hydrogel through the injured tissue. Gross histology was used to assess distribution of conductive hydrogel in the tissue. Results The conductive hydrogel viscosity was optimized to decrease with increasing shear rate to allow expression through a syringe. The direct current conductivity under aqueous conduction was 4.3 x 10(-1) S/cm. In four canine hearts, when compared with the homogeneous baseline conduction, isochronal maps demonstrated sequential myocardial activation with a shift in direction of activation to surround the edges of the ablated region. After injection of the conductive hydrogel, isochrones demonstrated conduction through the ablated tissue with activation restored through the ablated tissue. Gross specimen examination demonstrated retention of the hydrogel within the tissue. Conclusions This proof-of-concept study demonstrates that conductive hydrogel can be injected into acutely disrupted myocardium to restore conduction. Future experiments should focus on evaluating long-term retention and biocompatibility of the hydrogel through in vivo experimentation.
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| 4. |
- Walladbegi, Java, et al.
(författare)
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Three-dimensional bioprinting using a coaxial needle with viscous inks in bone tissue engineering - An in vitro study
- 2020
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Ingår i: Annals of Maxillofacial Surgery. - : Medknow. - 2249-3816 .- 2231-0746. ; 10:2, s. 370-376
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Vascularized autologous tissue grafts are considered 'gold standard' for the management of larger bony defects in the craniomaxillofacial area. This modality does however carry limitations, such as the absolute requirement for healthy donor tissues and recipient vessels. In addition, the significant morbidity of large bone graft is deterrent to fibula bone flap use. Therefore, less morbid strategies would be beneficial. The purpose of this study was to develop a printing method to manufacture scaffold structure with viable stem cells. Materials and Methods: In total, three different combinations of ground beta tri-calcium phosphate and CELLINK (bioinks) were printed with a nozzle to identify a suitable bioink for three-dimensional printing. Subsequently, a coaxial needle, with three different nozzle gauge combinations, was evaluated for printing of the bioinks. Scaffold structures (grids) were then printed alone and with additional adipose stem cells before being transferred into an active medium and incubated overnight. Following incubation, grid stability was evaluated by assessing the degree of maintained grid outline, and cell viability was determined using the live/dead cell assay. Results: Among the three evaluated combinations of bioinks, two resulted in good printability for bioprinting. Adequate printing was obtained with two out of the three nozzle gauge combinations tested. However, due to the smaller total opening, one combination revealed a better stability. Intact grids with maintained stability were obtained using Ink B23 and Ink B42, and approximately 80% of the printed stem cells were viable following 24 hours. Discussion: Using a coaxial needle enables printing of a stable scaffold with viable stem cells. Furthermore, cell viability is maintained after the bioprinting process.
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