1
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Anbazhakan S, Rios Coronado PE, Sy-Quia ANL, Seow LW, Hands AM, Zhao M, Dong ML, Pfaller MR, Amir ZA, Raftrey BC, Cook CK, D’Amato G, Fan X, Williams IM, Jha SK, Bernstein D, Nieman K, Pașca AM, Marsden AL, Horse KR. Blood flow modeling reveals improved collateral artery performance during the regenerative period in mammalian hearts. NATURE CARDIOVASCULAR RESEARCH 2022; 1:775-790. [PMID: 37305211 PMCID: PMC10256232 DOI: 10.1038/s44161-022-00114-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 07/07/2022] [Indexed: 06/13/2023]
Abstract
Collateral arteries bridge opposing artery branches, forming a natural bypass that can deliver blood flow downstream of an occlusion. Inducing coronary collateral arteries could treat cardiac ischemia, but more knowledge on their developmental mechanisms and functional capabilities is required. Here we used whole-organ imaging and three-dimensional computational fluid dynamics modeling to define spatial architecture and predict blood flow through collaterals in neonate and adult mouse hearts. Neonate collaterals were more numerous, larger in diameter and more effective at restoring blood flow. Decreased blood flow restoration in adults arose because during postnatal growth coronary arteries expanded by adding branches rather than increasing diameters, altering pressure distributions. In humans, adult hearts with total coronary occlusions averaged 2 large collaterals, with predicted moderate function, while normal fetal hearts showed over 40 collaterals, likely too small to be functionally relevant. Thus, we quantify the functional impact of collateral arteries during heart regeneration and repair-a critical step toward realizing their therapeutic potential.
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Affiliation(s)
- Suhaas Anbazhakan
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- These authors contributed equally
| | - Pamela E. Rios Coronado
- Department of Biology, Stanford University, Stanford, CA 94305, USA
- These authors contributed equally
| | | | - Lek Wei Seow
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Aubrey M. Hands
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Mingming Zhao
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Melody L. Dong
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Martin R. Pfaller
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, 94305
| | - Zhainib A. Amir
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Brian C. Raftrey
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | | | - Gaetano D’Amato
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Xiaochen Fan
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Ian M. Williams
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Sawan K. Jha
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Daniel Bernstein
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Koen Nieman
- Departments of Cardiovascular Medicine and Radiology, School of Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Anca M. Pașca
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, 94305
| | - Alison L. Marsden
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kristy Red Horse
- Department of Biology, Stanford University, Stanford, CA 94305, USA
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford, CA, 94305, USA
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2
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Sharma G, Wen X, Maptue NR, Hever T, Malloy CR, Sherry AD, Khemtong C. Co-Polarized [1- 13C]Pyruvate and [1,3- 13C 2]Acetoacetate Provide a Simultaneous View of Cytosolic and Mitochondrial Redox in a Single Experiment. ACS Sens 2021; 6:3967-3977. [PMID: 34761912 DOI: 10.1021/acssensors.1c01225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Cellular redox is intricately linked to energy production and normal cell function. Although the redox states of mitochondria and cytosol are connected by shuttle mechanisms, the redox state of mitochondria may differ from redox in the cytosol in response to stress. However, detecting these differences in functioning tissues is difficult. Here, we employed 13C magnetic resonance spectroscopy (MRS) and co-polarized [1-13C]pyruvate and [1,3-13C2]acetoacetate ([1,3-13C2]AcAc) to monitor production of hyperpolarized (HP) lactate and β-hydroxybutyrate as indicators of cytosolic and mitochondrial redox, respectively. Isolated rat hearts were examined under normoxic conditions, during low-flow ischemia, and after pretreatment with either aminooxyacetate (AOA) or rotenone. All interventions were associated with an increase in [Pi]/[ATP] measured by 31P NMR. In well-oxygenated untreated hearts, rapid conversion of HP [1-13C]pyruvate to [1-13C]lactate and [1,3-13C2]AcAc to [1,3-13C2]β-hydroxybutyrate ([1,3-13C2]β-HB) was readily detected. A significant increase in HP [1,3-13C2]β-HB but not [1-13C]lactate was observed in rotenone-treated and ischemic hearts, consistent with an increase in mitochondrial NADH but not cytosolic NADH. AOA treatments did not alter the productions of HP [1-13C]lactate or [1,3-13C2]β-HB. This study demonstrates that biomarkers of mitochondrial and cytosolic redox may be detected simultaneously in functioning tissues using co-polarized [1-13C]pyruvate and [1,3-13C2]AcAc and 13C MRS and that changes in mitochondrial redox may precede changes in cytosolic redox.
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Affiliation(s)
- Gaurav Sharma
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
| | - Xiaodong Wen
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
| | - Nesmine R. Maptue
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
| | - Thomas Hever
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
| | - Craig R. Malloy
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
| | - A. Dean Sherry
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
- Department of Chemistry, University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Chalermchai Khemtong
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, United States
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Florida, Gainesville, Florida 32610, United States
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610, United States
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3
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Barajas-Espinosa A, Basye A, Angelos MG, Chen CA. Modulation of p38 kinase by DUSP4 is important in regulating cardiovascular function under oxidative stress. Free Radic Biol Med 2015; 89:170-81. [PMID: 26184564 PMCID: PMC4684778 DOI: 10.1016/j.freeradbiomed.2015.07.013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 07/04/2015] [Accepted: 07/09/2015] [Indexed: 11/23/2022]
Abstract
Over-activation of p38 is implicated in many cardiovascular diseases (CVDs), including myocardial infarction, hypertrophy, heart failure, and ischemic heart disease. Numerous therapeutic interventions for CVDs have been directed toward the inhibition of the p38 mitogen-activated protein kinase activation that contributes to the detrimental effect after ischemia/reperfusion (I/R) injuries. However, the efficacy of these treatments is far from ideal, as they lack specificity and are associated with high toxicity. Previously, we demonstrated that N-acetyl cysteine (NAC) pretreatment up-regulates DUSP4 expression in endothelial cells, regulating p38 and ERK1/2 activities, and thus providing a protective effect against oxidative stress. Here, endothelial cells under hypoxia/reoxygenation (H/R) insult and isolated heart I/R injury were used to investigate the role of DUSP4 in the modulation of the p38 pathway. In rat endothelial cells, DUSP4 is time-dependently degraded by H/R (0.25 ± 0.07-fold change of control after 2h H/R). Its degradation is closely associated with hyperphosphorylation of p38 (2.1 ± 0.36-fold change) and cell apoptosis, as indicated by the increase in cells immunopositive for cleaved caspase-3 (12.59 ± 3.38%) or TUNEL labeling (29.46 ± 3.75%). The inhibition of p38 kinase activity with 20 µM SB203580 during H/R prevents H/R-induced apoptosis, assessed via TUNEL (12.99 ± 1.89%). Conversely, DUSP4 gene silencing in endothelial cells augments their sensitivity to H/R-induced apoptosis (45.81 ± 5.23%). This sensitivity is diminished via the inhibition of p38 activity (total apoptotic cells drop to 17.47 ± 1.45%). Interestingly, DUSP4 gene silencing contributes to the increase in superoxide generation from cells. Isolated Langendorff-perfused mouse hearts were subjected to global I/R injury. DUSP4(-/-) hearts had significantly larger infarct size than WT. The increase in I/R-induced infarct in DUSP4(-/-) mice significantly correlates with reduced functional recovery (assessed by RPP%, LVDP%, HR%, and dP/dtmax) as well as lower CF% and a higher initial LVEDP. From immunoblotting analysis, it is evident that p38 is significantly overactivated in DUSP4(-/-) mice after I/R injury. The activation of cleaved caspase-3 is seen in both WT and DUSP4(-/-) I/R hearts. Infusion of a p38 inhibitor prior to ischemia and during the reperfusion improves both WT and DUSP4(-/-) cardiac function. Therefore, the identification of p38 kinase modulation by DUSP4 provides a novel therapeutic target for oxidant-induced diseases, especially myocardial infarction.
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Affiliation(s)
- Alma Barajas-Espinosa
- Department of Emergency Medicine and the Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus OH, 43210USA
| | - Ariel Basye
- Department of Emergency Medicine and the Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus OH, 43210USA
| | - Mark G Angelos
- Department of Emergency Medicine and the Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus OH, 43210USA
| | - Chun-An Chen
- Department of Emergency Medicine and the Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus OH, 43210USA.
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Güçyetmez B, Atalan HK, Aloglu H, Kelebek A, Açıl T. Nocturnal hypoxia and the success rate of standard atrial fibrillation treatment: a case report. J Med Case Rep 2015; 9:133. [PMID: 26048677 PMCID: PMC4469246 DOI: 10.1186/s13256-015-0616-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 05/12/2015] [Indexed: 11/24/2022] Open
Abstract
Introduction Sleep apnea-hypopnea syndrome (SAHS) is one of the extracardiac reasons of atrial fibrillation (AF), and the prevalence of AF is high in SAHS-diagnosed patients. Nocturnal hypoxemia is associated with AF, pulmonary hypertension, and nocturnal death. The rate of AF recurrence is high in untreated SAHS-diagnosed patients after cardioversion (CV). In this study, we present a patient whose SAHS was diagnosed with an apnea test performed in the intensive care unit (ICU) and who did not develop recurrent AF after the administration of standard AF treatment and bi-level positive airway pressure (BiPAP). Case presentation A 57-year-old male hypertensive Caucasian patient who was on medical treatment for 1.5 months for non-organic AF was admitted to the ICU because of high-ventricular response AF (170 per minute), and sinus rhythm was maintained during the CV that was performed two times every second day. The results of the apnea test performed in the ICU on the same night after the second CV were as follows: apnea-hypopnea index (AHI) of 71 per hour, minimum peripheral oxygen saturation (SpO2) of 67%, and desaturation period (SpO2 of less than 90%) of 28 minutes. The patient was discharged with medical treatment and nocturnal BiPAP treatment. The results of the apnea test performed under BiPAP on the sixth month were as follows: AHI of 1 per hour, desaturation period of 1 minute, and minimum SpO2 of 87%. No recurrent AF developed in the patient, and his medical treatment was reduced within 6 months. After gastric bypass surgery on the 12th month, nocturnal hypoxia and AF did not re-occur. Thus, BiPAP and medical treatments were ended. Conclusions SAHS can be diagnosed by performing an apnea test in the ICU. SAHS should be investigated in patients developing recurrent AF after CV. Recovery of nocturnal hypoxia may increase the success rate of standard AF treatment.
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Affiliation(s)
- Bülent Güçyetmez
- Department of Anesthesiology, Acıbadem University Faculty of Medicine, Istanbul, Turkey. .,Intensive Care Unit, Acibadem International Hospital, Istanbul Cad No. 82 Yesilkoy, 34149, Istanbul, Turkey.
| | - Hakan Korkut Atalan
- Intensive Care Unit, Ataşehir Memorial Hospital, Vedat Gunyol Cad No. 28 Kucukbakkalkoy Atasehir, 34758, Istanbul, Turkey.
| | - Hikmet Aloglu
- Department of Neurology, Medicalpark Bahçelievler Hospital, Kültür Sok No. 1 Bahçelievler, 34160, Istanbul, Turkey.
| | - Adnan Kelebek
- Department of Cardiology, Acibadem International Hospital, Istanbul Cad No. 82 Yesilkoy, 34149, Istanbul, Turkey.
| | - Tayfun Açıl
- Department of Cardiology, Acibadem International Hospital, Istanbul Cad No. 82 Yesilkoy, 34149, Istanbul, Turkey.
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5
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Madamanchi NR, Runge MS. Redox signaling in cardiovascular health and disease. Free Radic Biol Med 2013; 61:473-501. [PMID: 23583330 PMCID: PMC3883979 DOI: 10.1016/j.freeradbiomed.2013.04.001] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 03/05/2013] [Accepted: 04/02/2013] [Indexed: 02/07/2023]
Abstract
Spatiotemporal regulation of the activity of a vast array of intracellular proteins and signaling pathways by reactive oxygen species (ROS) governs normal cardiovascular function. However, data from experimental and animal studies strongly support that dysregulated redox signaling, resulting from hyperactivation of various cellular oxidases or mitochondrial dysfunction, is integral to the pathogenesis and progression of cardiovascular disease (CVD). In this review, we address how redox signaling modulates the protein function, the various sources of increased oxidative stress in CVD, and the labyrinth of redox-sensitive molecular mechanisms involved in the development of atherosclerosis, hypertension, cardiac hypertrophy and heart failure, and ischemia-reperfusion injury. Advances in redox biology and pharmacology for inhibiting ROS production in specific cell types and subcellular organelles combined with the development of nanotechnology-based new in vivo imaging systems and targeted drug delivery mechanisms may enable fine-tuning of redox signaling for the treatment and prevention of CVD.
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Affiliation(s)
- Nageswara R Madamanchi
- McAllister Heart Institute, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | - Marschall S Runge
- McAllister Heart Institute, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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6
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Abstract
Reactive oxygen/nitrogen species (ROS/RNS) have been increasingly recognized as important mediators and play a number of critical roles in cell injury, metabolism, disease pathology, diagnosis, and clinical treatment. Electron paramagnetic resonance (EPR) spectroscopy enables the spectral information at certain spatial position, and, from the observed line-width and signal intensity, the localized tissue oxygenation, and tissue redox status can be determined. We applied in vivo EPR oximetry and redoximetry technique and implemented its physiological/pathophysiological applications, along with the use of biocompatible lithium pthalocyanine (liPc) and nitroxide redox sensitive probes, on in vivo tissue oxygenation and redox profile of the ischemic and reperfused heart in living animals. We have observed that the hypoxia during myocardial ischemia limited mitochondrial respiration and caused a shift of tissue redox status to a more reduced state. ROS/RNS generated at the beginning of reperfusion not only caused a shift of redox status to a more oxidized state which may contribute to the postischemic myocardial injury, but also a marked suppression of in vivo tissue O(2) consumption in the postischemic heart through modulation of mitochondrial respiration based on alterations in enzyme activity and mRNA expression of NADH dehydrogenase (NADH-DH) and cytochrome c oxidase (CcO). In addition, ischemic preconditioning was found to be able to markedly attenuate postischemic myocardial hyperoxygenation with less ROS/RNS generation and preservation of mitochondrial O(2) metabolism, due to conserved NADH-DH and CcO activities. These studies have demonstrated that EPR oximetry and redoximetry techniques have advanced to a stage that enables in-depth insight in the process of ischemia reperfusion injury.
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Affiliation(s)
- Guanglong He
- The Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute and Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH, USA.
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7
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Ndrepepa G, Keta D, Schulz S, Byrne RA, Mehilli J, Pache J, Seyfarth M, Schömig A, Kastrati A. Prognostic value of minimal blood flow restoration in patients with acute myocardial infarction after reperfusion therapy. Clin Res Cardiol 2009; 99:13-9. [DOI: 10.1007/s00392-009-0070-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Accepted: 08/20/2009] [Indexed: 11/25/2022]
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8
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Holcomb MR, Woods MC, Uzelac I, Wikswo JP, Gilligan JM, Sidorov VY. The potential of dual camera systems for multimodal imaging of cardiac electrophysiology and metabolism. Exp Biol Med (Maywood) 2009; 234:1355-73. [PMID: 19657065 DOI: 10.3181/0902-rm-47] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Fluorescence imaging has become a common modality in cardiac electrodynamics. A single fluorescent parameter is typically measured. Given the growing emphasis on simultaneous imaging of more than one cardiac variable, we present an analysis of the potential of dual camera imaging, using as an example our straightforward dual camera system that allows simultaneous measurement of two dynamic quantities from the same region of the heart. The advantages of our system over others include an optional software camera calibration routine that eliminates the need for precise camera alignment. The system allows for rapid setup, dichroic image separation, dual-rate imaging, and high spatial resolution, and it is generally applicable to any two-camera measurement. This type of imaging system offers the potential for recording simultaneously not only transmembrane potential and intracellular calcium, two frequently measured quantities, but also other signals more directly related to myocardial metabolism, such as [K(+)](e), NADH, and reactive oxygen species, leading to the possibility of correlative multimodal cardiac imaging. We provide a compilation of dye and camera information critical to the design of dual camera systems and experiments.
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Affiliation(s)
- Mark R Holcomb
- Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235-1807, USA
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9
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Mokrý M, Gál P, Harakalová M, Hutnanová Z, Kusnír J, Mozes S, Sabo J. Experimental study on predicting skin flap necrosis by fluorescence in the FAD and NADH bands during surgery. Photochem Photobiol 2008; 83:1193-6. [PMID: 17880514 DOI: 10.1111/j.1751-1097.2007.00132.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The objective of the present study was to assess the feasibility of using endogenous fluorescence in intraoperative prediction of skin flap necrosis. The investigation was carried out in 10 Sprague-Dawley rats in which proximally based over-dimensioned random pattern skin flaps were dissected on the back and thereafter fixed into position. Immediately after surgery on each rat, synchronous fluorescence spectra (Deltalambda=90 nm) from five parts of the skin flap surface were measured. The presence of necrosis was evaluated on postoperative day 7. In flap parts designated as necrotic (n=18), a significantly lower (P<0.001) fluorescent signal from the nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) bands (360-380 and 440-460 nm, respectively) was detected in comparison with the vital parts (n=32) (for FAD:1767+/-39 versus 2579+/-65 auxiliary units [A.U]. and for NADH:11724+/-340 versus 16810+/-473 A.U.). The results suggested a close relationship between the fluorescent signals from the FAD and NADH bands on one side and flap necrosis or survival on the other side. Thus, the use of fluorescence spectroscopy may be considered as a valuable noninvasive tool for the prediction of skin flap necrosis.
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Affiliation(s)
- Michal Mokrý
- Department of Medical Chemistry, Biochemistry and Clinical Biochemistry, Faculty of Medicine, Pavol Jozef Safárik University in Kosice, Slovak Republic.
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10
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Pfeifer L, Gruenwald I, Welker A, Stahn RM, Stein K, Rex A. Fluorimetric characterisation of metabolic activity of ex vivo perfused pig hearts. BIOMED ENG-BIOMED TE 2007; 52:193-9. [PMID: 17408379 DOI: 10.1515/bmt.2007.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Autofluorescence of tissues and organs is an indicator of the physiological state of cells. The aim of the study was to investigate whether fluorimetric determination of the redox state of the ex vivo perfused pig heart can provide fast online detection of progressive changes in heart muscle tissue. Measurements on six organs perfused in a four-chamber working heart model were performed using a spectroscopic method exploiting the specific and different fluorescence lifetimes of intrinsic fluorophores such as NADH and flavins and providing a means of internal signal referencing. It was shown that the redox potential of heart muscle tissue can be assessed by fluorescence measurement. In the steady-state phase of the beating heart, spectroscopic measurements revealed a change in redox state from an initial constant level to a continuous decrease, accompanied by a decrease in heart performance and indications of changes in electrolyte equilibrium (K(+) concentration). At the same time, troponin I levels in the perfusate increased. The results indicate that fluorimetric determination of heart muscle metabolic activity yields reliable information about the functional status of the ex vivo heart and may be advantageous for the optimisation of ex vivo organ models.
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Affiliation(s)
- Lutz Pfeifer
- IOM Innovative Optische Messtechnik GmbH, Berlin, Germany.
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11
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Zhu X, Zuo L, Cardounel AJ, Zweier JL, He G. Characterization of in vivo tissue redox status, oxygenation, and formation of reactive oxygen species in postischemic myocardium. Antioxid Redox Signal 2007; 9:447-55. [PMID: 17280486 DOI: 10.1089/ars.2006.1389] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The current study aims to characterize the alterations of in vivo tissue redox status, oxygenation, formation of reactive oxygen species (ROS), and their effects on the postischemic heart. Mouse heart was subjected to 30 min LAD occlusion, followed by 60 min reperfusion. In vivo myocardial redox status and oxygenation were measured with electron paramagnetic resonance (EPR). In vivo tissue NAD(P)H and formation of ROS were monitored with fluorometry. Tissue glutathione/glutathione disulfide (GSH/GSSG) levels were detected with high-performance liquid chromatography (HPLC). These experiments demonstrated that tissue reduction rate of nitroxide was increased 100% during ischemia and decreased 33% after reperfusion compared to the nonischemic tissue. There was an overshoot of tissue oxygenation after reperfusion. Tissue NAD(P)H levels were increased during and after ischemia. There was a burst formation of ROS at the beginning of reperfusion. Tissue GSH/GSSG level showed a 48% increase during ischemia and 29% decrease after reperfusion. In conclusion, the hypoxia during ischemia limited mitochondrial respiration and caused a shift of tissue redox status to a more reduced state. ROS generated at the beginning of reperfusion caused a shift of redox status to a more oxidized state, which may contribute to the postischemic myocardial injury.
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Affiliation(s)
- Xuehai Zhu
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
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12
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Stoner JD, Clanton TL, Aune SE, Angelos MG. O2 delivery and redox state are determinants of compartment-specific reactive O2 species in myocardial reperfusion. Am J Physiol Heart Circ Physiol 2006; 292:H109-16. [PMID: 17028160 DOI: 10.1152/ajpheart.00925.2006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reperfusion of the ischemic myocardium leads to a burst of reactive O(2) species (ROS), which is a primary determinant of postischemic myocardial dysfunction. We tested the hypothesis that early O(2) delivery and the cellular redox state modulate the initial myocardial ROS production at reperfusion. Isolated buffer-perfused rat hearts were loaded with the fluorophores dihydrofluorescein or Amplex red to detect intracellular and extracellular ROS formation using surface fluorometry at the left ventricular wall. Hearts were made globally ischemic for 20 min and then reperfused with either 95% or 20% O(2)-saturated perfusate. The same protocol was repeated in hearts loaded with dihydrofluorescein and perfused with either 20 or 5 mM glucose-buffered solution to determine relative changes in NADH and FAD. Myocardial O(2) delivery during the first 5 min of reperfusion was 84.7 +/- 4.2 ml O(2)/min with 20% O(2)-saturated buffer and 354.4 +/- 22.8 ml O(2)/min with 95% O(2) (n = 8/group, P < 0.001). The fluorescein signal (intracellular ROS) was significantly increased in hearts reperfused with 95% O(2) compared with 20% O(2). However, the resorufin signal (extracellular ROS) was significantly increased with 20% O(2) compared with 95% O(2) during reperfusion. Perfusion of hearts with 20 mM glucose reduced the (.)NADH during ischemia (P < 0.001) and the (.)ROS at reperfusion (P < 0.001) compared with 5.5 mM-perfused glucose hearts. In conclusion, initial O(2) delivery to the ischemic myocardium modulates a compartment-specific ROS response at reperfusion such that high O(2) delivery promotes intracellular ROS and low O(2) delivery promotes extracellular ROS. The redox state that develops during ischemia appears to be an important precursor for reperfusion ROS production.
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Affiliation(s)
- Jason D Stoner
- Dept. of Emergency Medicine, The Ohio State Univ., 146 Means Hall, 1654 Upham Dr., Columbus, OH 43210, USA
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13
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Palmer BS, Hadziahmetovic M, Veci T, Angelos MG. Global ischemic duration and reperfusion function in the isolated perfused rat heart. Resuscitation 2004; 62:97-106. [PMID: 15246589 DOI: 10.1016/j.resuscitation.2003.12.027] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2003] [Revised: 12/09/2003] [Accepted: 12/09/2003] [Indexed: 10/26/2022]
Abstract
Post-ischemic myocardial dysfunction has been observed in a variety of clinical situations including cardiac arrest. Potentially survivable cardiac arrest following short-term global myocardial ischemia may be of insufficient duration to cause irreversible myocyte injury, but still results in contractile and bioenergetic dysfunction. The purpose of this study was to characterize the ischemic transition from reversible to irreversible injury in the isolated perfused rat heart. Isolated, buffer perfused, male Sprague-Dawley rat hearts underwent normothermic ischemia of 15, 20, 25 or 30 min with or without 30 min of reperfusion and were freeze clamped in liquid nitrogen for bioenergetic analysis of LV tissue. Post-ischemic LV function and measurements of bioenergetic recovery were made between groups and with non-ischemic controls. Baseline LV function was similar in all groups. Post-ischemic contractile function was markedly depressed in the 25 and 30 min ischemia groups with persistent depression of high-energy phosphates, total adenine nucleotide pool, myocardial oxygen consumption, elevated CK release and evidence of significant mitochondrial edema in the 30 min group. In contrast with longer ischemic periods, the reduction in LV contractile function after 15 and 20 min of ischemia was mild, with more complete bioenergetic recovery, minimal CK release, and normal appearing mitochondrial. This data suggests a period of transition from reversible to irreversible injury occurring at approximately 20 min of normothermic global ischemia in the isolated perfused rat heart.
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Affiliation(s)
- Brian S Palmer
- Department of Emergency Medicine, The Ohio State University, 146 Means Hall, 1654 Upham Dr., Columbus, OH 43210, USA
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