1
|
Syed UT, Dias AM, Crespo J, Brazinha C, de Sousa HC. Studies on the formation and stability of perfluorodecalin nanoemulsions by ultrasound emulsification using novel surfactant systems. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126315] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
2
|
Perfluorocarbon Gas Transport: an Overview of Medical History With Yet Unrealized Potentials. Shock 2019; 52:7-12. [DOI: 10.1097/shk.0000000000001150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
3
|
Alfonso JCL, Köhn-Luque A, Stylianopoulos T, Feuerhake F, Deutsch A, Hatzikirou H. Why one-size-fits-all vaso-modulatory interventions fail to control glioma invasion: in silico insights. Sci Rep 2016; 6:37283. [PMID: 27876890 PMCID: PMC5120360 DOI: 10.1038/srep37283] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/26/2016] [Indexed: 12/18/2022] Open
Abstract
Gliomas are highly invasive brain tumours characterised by poor prognosis and limited response to therapy. There is an ongoing debate on the therapeutic potential of vaso-modulatory interventions against glioma invasion. Prominent vasculature-targeting therapies involve tumour blood vessel deterioration and normalisation. The former aims at tumour infarction and nutrient deprivation induced by blood vessel occlusion/collapse. In contrast, the therapeutic intention of normalising the abnormal tumour vasculature is to improve the efficacy of conventional treatment modalities. Although these strategies have shown therapeutic potential, it remains unclear why they both often fail to control glioma growth. To shed some light on this issue, we propose a mathematical model based on the migration/proliferation dichotomy of glioma cells in order to investigate why vaso-modulatory interventions have shown limited success in terms of tumour clearance. We found the existence of a critical cell proliferation/diffusion ratio that separates glioma responses to vaso-modulatory interventions into two distinct regimes. While for tumours, belonging to one regime, vascular modulations reduce the front speed and increase the infiltration width, for those in the other regime, the invasion speed increases and infiltration width decreases. We discuss how these in silico findings can be used to guide individualised vaso-modulatory approaches to improve treatment success rates.
Collapse
Affiliation(s)
- J C L Alfonso
- Braunschweig Integrated Centre of Systems Biology and Helmholtz Center for Infectious Research, Braunschweig, Germany.,Center for Information Services and High Performance Computing, Technische Universität Dresden, Germany
| | - A Köhn-Luque
- Department of Biostatistics, Faculty of Medicine, University of Oslo, Norway.,BigInsight, Centre for Research-based Innovation (SFI), Oslo, Norway
| | - T Stylianopoulos
- Cancer Biophysics Laboratory, Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, Cyprus
| | - F Feuerhake
- Institute of Pathology, Medical School of Hannover, Germany.,Institute of Neuropathology, University Clinic Freiburg, Germany
| | - A Deutsch
- Center for Information Services and High Performance Computing, Technische Universität Dresden, Germany
| | - H Hatzikirou
- Braunschweig Integrated Centre of Systems Biology and Helmholtz Center for Infectious Research, Braunschweig, Germany
| |
Collapse
|
4
|
Haque A, Scultetus AH, Arnaud F, Dickson LJ, Chun S, McNamee G, Auker CR, McCarron RM, Mahon RT. The Emulsified PFC Oxycyte ® Improved Oxygen Content and Lung Injury Score in a Swine Model of Oleic Acid Lung Injury (OALI). Lung 2016; 194:945-957. [PMID: 27704259 DOI: 10.1007/s00408-016-9941-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 09/12/2016] [Indexed: 01/20/2023]
Abstract
PURPOSE Perfluorocarbons (PFCs) can transport 50 times more oxygen than human plasma. Their properties may be advantageous in preservation of tissue viability in oxygen-deprived states, such as in acute lung injury. We hypothesized that an intravenous dose of the PFC emulsion Oxycyte® would improve tissue oxygenation and thereby mitigate the effects of acute lung injury. METHODS Intravenous oleic acid (OA) was used to induce lung injury in anesthetized and instrumented Yorkshire swine assigned to three experimental groups: (1) PFC post-OA received Oxycyte® (5 ml/kg) 45 min after oleic acid-induced lung injury (OALI); (2) PFC pre-OA received Oxycyte® 45 min before OALI; and (3) Controls which received equivalent dose of normal saline. Animals were observed for 3 h after OALI began, and then euthanized. RESULTS The median survival times for PFC post-OA, PFC pre-OA, and control were 240, 87.5, and 240 min, respectively (p = 0.001). Mean arterial pressure and mean pulmonary arterial pressure were both higher in the PFC post-OA (p < 0.001 for both parameters). Oxygen content was significantly different between PFC post-OA and the control (p = 0.001). Histopathological grading of lung injury indicated that edema and congestion was significantly less severe in the PFC post-OA compared to control (p = 0.001). CONCLUSION The intravenous PFC Oxycyte® improves blood oxygen content and lung histology when used as a treatment after OALI, while Oxycyte® used prior to OALI was associated with increased mortality. Further exploration in other injury models is indicated.
Collapse
Affiliation(s)
- Ashraful Haque
- NeuroTrauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD, 20910-7500, USA.
| | - Anke H Scultetus
- NeuroTrauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD, 20910-7500, USA
- Department of Surgery, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - Francoise Arnaud
- NeuroTrauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD, 20910-7500, USA
- Department of Surgery, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - Leonora J Dickson
- Department of Pathology, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD, 20910-7500, USA
| | - Steve Chun
- NeuroTrauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD, 20910-7500, USA
- Department of Surgery, Walter Reed National Military Medical Center, 8901 Rockville Pike, Bethesda, MD, 20889, USA
| | - George McNamee
- Department of Surgery, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - Charles R Auker
- NeuroTrauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD, 20910-7500, USA
| | - Richard M McCarron
- NeuroTrauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD, 20910-7500, USA
- Department of Surgery, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814, USA
| | - Richard T Mahon
- Undersea Medicine Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD, 20910-7500, USA
| |
Collapse
|
5
|
Computational Simulations of Flow and Oxygen/Drug Delivery in a Three-Dimensional Capillary Network. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/359327] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A computational fluid dynamics (CFD) model is developed to simulate the flow and delivery of oxygen and other substances in a capillary network. A three-dimensional capillary network has been constructed to replicate the one studied by Secomb et al. (2000), and the computational framework features a non-Newtonian viscosity model of blood and the oxygen transport model including in-stream oxygen-hemoglobin dissociation and wall flux due to tissue absorption, as well as an ability to study delivery of drugs and other materials in the capillary streams. The model is first run to compute the volumetric flow rates from the velocity profiles in the segments and compared with Secomb’s work with good agreement. Effects of abnormal pressure and stenosis conditions, as well as those arising from different capillary configurations, on the flow and oxygen delivery are investigated, along with a brief look at the unsteady effects and drug dispersion in the capillary network. The current approach allows for inclusion of oxygen and other material transports, including drugs, nutrients, or contaminants based on the flow simulations. Also, three-dimensional models of complex circulatory systems ranging in scale from macro- to microvascular vessels, in principle, can be constructed and analyzed in detail using the current method.
Collapse
|
6
|
Pittman RN. Oxygen transport in the microcirculation and its regulation. Microcirculation 2013; 20:117-37. [PMID: 23025284 DOI: 10.1111/micc.12017] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 09/27/2012] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Cells require energy to carry out their functions and they typically use oxidative phosphorylation to generate the needed ATP. Thus, cells have a continuous need for oxygen, which they receive by diffusion from the blood through the interstitial fluid. The circulatory system pumps oxygen-rich blood through a network of increasingly minute vessels, the microcirculation. The structure of the microcirculation is such that all cells have at least one nearby capillary for diffusive exchange of oxygen and red blood cells release the oxygen bound to hemoglobin as they traverse capillaries. METHODS This review focuses first on the historical development of techniques to measure oxygen at various sites in the microcirculation, including the blood, interstitium, and cells. RESULTS Next, approaches are described as to how these techniques have been employed to make discoveries about different aspects of oxygen transport. Finally, ways in which oxygen might participate in the regulation of blood flow toward matching oxygen supply to oxygen demand is discussed. CONCLUSIONS Overall, the transport of oxygen to the cells of the body is one of the most critical functions of the cardiovascular system and it is in the microcirculation where the final local determinants of oxygen supply, oxygen demand, and their regulation are decided.
Collapse
Affiliation(s)
- Roland N Pittman
- Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, Virginia, USA.
| |
Collapse
|
7
|
Baete SH, Vandecasteele J, De Deene Y. 19F MRI oximetry: simulation of perfluorocarbon distribution impact. Phys Med Biol 2011; 56:2535-57. [PMID: 21444970 DOI: 10.1088/0031-9155/56/8/013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In (19)F MRI oximetry, a method used to image tumour hypoxia, perfluorocarbons serve as oxygenation markers. The goal of this study is to evaluate the impact of perfluorocarbon distribution and concentration in (19)F MRI oximetry through a computer simulation. The simulation studies the correspondence between (19)F measured (pO(FNMR)(2)) and actual tissue oxygen tension (pO(2)) for several tissue perfluorocarbon distributions. For this, a Krogh tissue model is implemented which incorporates the presence of perfluorocarbons in blood and tissue. That is, in tissue the perfluorocarbons are distributed homogeneously according to Gaussian diffusion profiles, or the perfluorocarbons are concentrated in the capillary wall. Using these distributions, the oxygen tension in the simulation volume is calculated. The simulated mean oxygen tension is then compared with pO(FNMR)(2), the (19)F MRI-based measure of pO(2) and with pO(0)(2), pO(2) in the absence of perfluorocarbons. The agreement between pO(FNMR)(2) and actual pO(2) is influenced by vascular density and perfluorocarbon distribution. The presence of perfluorocarbons generally gives rise to a pO(2) increase in tissue. This effect is enhanced when perfluorocarbons are also present in blood. Only the homogeneous perfluorocarbon distribution in tissue with no perfluorocarbons in blood guarantees small deviations of pO(FNMR)(2) from pO(2). Hence, perfluorocarbon distribution in tissue and blood has a serious impact on the reliability of (19)F MRI-based measures of oxygen tension. In addition, the presence of perfluorocarbons influences the actual oxygen tension. This finding may be of great importance for further development of (19)F MRI oximetry.
Collapse
Affiliation(s)
- S H Baete
- Department of Radiation Oncology and Experimental Cancer Research, Ghent University, De Pintelaan 185, 9000 Gent, Belgium.
| | | | | |
Collapse
|
8
|
Spiess BD. Perfluorocarbon emulsions as a promising technology: a review of tissue and vascular gas dynamics. J Appl Physiol (1985) 2009; 106:1444-52. [PMID: 19179651 DOI: 10.1152/japplphysiol.90995.2008] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Perfluorocarbon (PFC) emulsions are halogen-substituted carbon nonpolar oils with resultant enhanced dissolved respiratory gas (O(2), N(2), CO(2), nitric oxide) capabilities. In the first demonstration of enhanced O(2) solubility, inhaled PFC could sustain rat metabolism. Intravenous emulsions were then trialed as "blood substitutes." In the last 10 yr, biocomputational modeling has enhanced our mechanistic understanding of PFCs. Contemporary research is now taking advantage of these physiological discoveries and applying PFCs as "oxygen therapeutics," as well as ways to enhance other gas movements. One particularly promising area of research is the treatment of gas embolism (arterial and venous emboli/decompression sickness). An expansive understanding of PFC-enhanced diffusive gas movements through tissue and vasculature may have analogous applications for O(2) or other respiratory gases and should provide a revolution in medicine. This review will stress the fundamental knowledge we now have regarding how respiratory gas movements are changed when intravenous PFC is present.
Collapse
Affiliation(s)
- Bruce D Spiess
- Department of Anesthesiology and Emergency Medicine, Virginia Commonwealth University Reanimation Engineering Shock Center, Richmond, Virginia, USA.
| |
Collapse
|
9
|
Barker MC, Golub AS, Pittman RN. Erythrocyte-associated transients in capillary PO2: an isovolemic hemodilution study in the rat spinotrapezius muscle. Am J Physiol Heart Circ Physiol 2007; 292:H2540-9. [PMID: 17277027 DOI: 10.1152/ajpheart.00915.2006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mathematical simulations of oxygen delivery to tissue from capillaries that take into account the particulate nature of blood flow predict the existence of oxygen tension (Po(2)) gradients between erythrocytes (RBCs). As RBCs and plasma alternately pass an observation point, these gradients are manifested as rapid fluctuations in Po(2), also known as erythrocyte-associated transients (EATs). The impact of hemodilution on EATs and oxygen delivery at the capillary level of the microcirculation has yet to be elucidated. Therefore, in the present study, phosphorescence quenching microscopy was used to measure EATs and Po(2) in capillaries of the rat spinotrapezius muscle at the following systemic hematocrits (Hct(sys)): normal (39%) and after moderate (HES1; 27%) or severe (HES2; 15%) isovolemic hemodilution using a 6% hetastarch solution. A 532-nm laser, generating 10-micros pulses concentrated onto a 0.9-microm spot, was used to obtain plasma Po(2) values 100 times/s at points along surface capillaries of the muscle. Mean capillary Po(2) (Pc(O(2)); means +/- SE) significantly decreased between conditions (normal: 56 +/- 2 mmHg, n = 45; HES1: 47 +/- 2 mmHg, n = 62; HES2: 27 +/- 2 mmHg, n = 52, where n = capillary number). In addition, the magnitude of Po(2) transients (DeltaPo(2)) significantly decreased with hemodilution (normal: 19 +/- 1 mmHg, n = 45; HES1: 11 +/- 1 mmHg, n = 62; HES2: 6 +/- 1 mmHg, n = 52). Results suggest that the decrease in Pc(O(2)) and DeltaPo(2) with hemodilution is primarily dependent on Hct(sys) and subsequent microvascular compensations.
Collapse
Affiliation(s)
- Matthew C Barker
- Department of Physiology, Medical College of Virginia Campus, Virginia Commonwealth University, 1101 E. Marshall Street, PO Box 980551, Richmond, VA 23298-0551, USA
| | | | | |
Collapse
|
10
|
Golub AS, Pittman RN. Erythrocyte-associated transients in PO2 revealed in capillaries of rat mesentery. Am J Physiol Heart Circ Physiol 2005; 288:H2735-43. [PMID: 15695557 DOI: 10.1152/ajpheart.00711.2004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mathematical models have predicted the existence of Po(2) gradients between erythrocytes in capillaries in the usual case where plasma contributes substantial resistance to oxygen diffusion. According to theoretical predictions, these gradients could be detected as rapid Po(2) fluctuations (erythrocyte-associated transients, EATs) along the capillary. However, verification of a model and correct choice of its parameters can be made only on the basis of direct experimental measurements. We used phosphorescence quenching microscopy to measure Po(2) in 52 capillaries of rat mesentery to obtain plasma Po(2) values 100 times/s at a given point along a capillary. A 532-nm laser generated 10-micros pulses of light, concentrated by a x100 objective, onto a spot 0.9 microm in diameter. The presence of erythrocytes in the excitation region was detected on the basis of phosphorescence amplitude (PA), proportional to the amount of plasma encountered by the laser beam, and on the basis of the intensity of transmitted laser light (LT), detected by a photodiode placed under the capillary. The data revealed correlated waveforms in PA, LT, and Po(2) in capillaries. The magnitude of the Po(2) gradients between erythrocytes and plasma was correlated with average capillary Po(2). EATs in Po(2) were more readily detected in capillaries with relatively low oxygenation. The correlation coefficients between PA and Po(2) for the half of the capillaries (n = 26) below the median Po(2) (mean Po(2) = 17 mmHg; R = -0.72) was higher than that for the other half (mean Po(2) = 39 mmHg; R = -0.38). These results support the theoretical predictions of EATs and plasma Po(2) gradients in capillaries.
Collapse
Affiliation(s)
- Aleksander S Golub
- Dept. of Physiology, Medical College of Virginia Campus, Virginia Commonwealth Univ., 1101 E. Marshall St., PO Box 980551, Richmond, VA 23298-0551, USA
| | | |
Collapse
|