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Pecchiari M, Pontikis K, Alevrakis E, Vasileiadis I, Kompoti M, Koutsoukou A. Cardiovascular Responses During Sepsis. Compr Physiol 2021; 11:1605-1652. [PMID: 33792902 DOI: 10.1002/cphy.c190044] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Sepsis is the life-threatening organ dysfunction arising from a dysregulated host response to infection. Although the specific mechanisms leading to organ dysfunction are still debated, impaired tissue oxygenation appears to play a major role, and concomitant hemodynamic alterations are invariably present. The hemodynamic phenotype of affected individuals is highly variable for reasons that have been partially elucidated. Indeed, each patient's circulatory condition is shaped by the complex interplay between the medical history, the volemic status, the interval from disease onset, the pathogen, the site of infection, and the attempted resuscitation. Moreover, the same hemodynamic pattern can be generated by different combinations of various pathophysiological processes, so the presence of a given hemodynamic pattern cannot be directly related to a unique cluster of alterations. Research based on endotoxin administration to healthy volunteers and animal models compensate, to an extent, for the scarcity of clinical studies on the evolution of sepsis hemodynamics. Their results, however, cannot be directly extrapolated to the clinical setting, due to fundamental differences between the septic patient, the healthy volunteer, and the experimental model. Numerous microcirculatory derangements might exist in the septic host, even in the presence of a preserved macrocirculation. This dissociation between the macro- and the microcirculation might account for the limited success of therapeutic interventions targeting typical hemodynamic parameters, such as arterial and cardiac filling pressures, and cardiac output. Finally, physiological studies point to an early contribution of cardiac dysfunction to the septic phenotype, however, our defective diagnostic tools preclude its clinical recognition. © 2021 American Physiological Society. Compr Physiol 11:1605-1652, 2021.
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Affiliation(s)
- Matteo Pecchiari
- Dipartimento di Fisiopatologia Medico Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - Konstantinos Pontikis
- Intensive Care Unit, 1st Department of Pulmonary Medicine, National & Kapodistrian University of Athens, General Hospital for Diseases of the Chest 'I Sotiria', Athens, Greece
| | - Emmanouil Alevrakis
- 4th Department of Pulmonary Medicine, General Hospital for Diseases of the Chest 'I Sotiria', Athens, Greece
| | - Ioannis Vasileiadis
- Intensive Care Unit, 1st Department of Pulmonary Medicine, National & Kapodistrian University of Athens, General Hospital for Diseases of the Chest 'I Sotiria', Athens, Greece
| | - Maria Kompoti
- Intensive Care Unit, Thriassio General Hospital of Eleusis, Magoula, Greece
| | - Antonia Koutsoukou
- Intensive Care Unit, 1st Department of Pulmonary Medicine, National & Kapodistrian University of Athens, General Hospital for Diseases of the Chest 'I Sotiria', Athens, Greece
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Portörő I, Mukli P, Kocsis L, Hermán P, Caccia D, Perrella M, Mozzarelli A, Ronda L, Mathe D, Eke A. Model-based evaluation of the microhemodynamic effects of PEGylated HBOC molecules in the rat brain cortex: a laser speckle imaging study. BIOMEDICAL OPTICS EXPRESS 2020; 11:4150-4175. [PMID: 32923034 PMCID: PMC7449705 DOI: 10.1364/boe.388089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/24/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
Hemoglobin-based oxygen carriers (HBOCs) were developed with the aim of substituting transfusions in emergency events. However, they exhibit adverse events, such as nitric oxide (NO) scavenging, vasoactivity, enhanced platelet aggregation, presently hampering their clinical application. The impact of two prototypical PEGylated HBOCs, Euro-PEG-Hb and PEG-HbO2, endowed by different oxygen affinities and hydrodynamic volumes, was assessed on the cerebrocortical parenchymal microhemodynamics, and extravasation through the blood-brain-barrier (BBB) by laser speckle contrast imaging (LSCI) method and near-infrared (NIR) imaging, respectively. By evaluating voxel-wise cerebrocortical red blood cell velocity, non-invasively for its mean kernel-wise value ( v ¯ RBC ), and model-derived kernel-wise predictions for microregional tissue hematocrit, THt, and fractional change in hematocrit-corrected vascular resistance, R', as measures of potential adverse effects (enhanced platelet aggregation and vasoactivity, respectively) we found i) no significant difference between tested HBOCs in the systemic and microregional parameters, and in the relative spatial dispersion of THt, and R' as additional measures of HBOC-related adverse effects, and ii) no extravasation through BBB by Euro-PEG-Hb. We conclude that Euro-PEG-Hb does not exhibit adverse effects in the brain microcirculation that could be directly attributed to NO scavenging.
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Affiliation(s)
- István Portörő
- Institute of Translational Medicine, Semmelweis University, Hungary
- These authors contributed equally to this work
| | - Péter Mukli
- Institute of Translational Medicine, Semmelweis University, Hungary
- Department of Physiology, Semmelweis University, Hungary
- These authors contributed equally to this work
| | - László Kocsis
- Institute of Translational Medicine, Semmelweis University, Hungary
| | - Péter Hermán
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, CT 06520, USA
| | - Dario Caccia
- Department of Biomedical Science and Technology, University of Milan, Italy
- Department of Food and Drug, University of Parma, Italy
| | - Michele Perrella
- Department of Biomedical Science and Technology, University of Milan, Italy
| | - Andrea Mozzarelli
- Department of Food and Drug, University of Parma, Italy
- Institute of Biophysics, National Research Council, Pisa, Italy
- Biopharmanet-TEC, University of Parma, Italy
| | - Luca Ronda
- Institute of Biophysics, National Research Council, Pisa, Italy
- Biopharmanet-TEC, University of Parma, Italy
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Domokos Mathe
- CROmed Research and Service Centers Ltd., Budapest, Hungary
| | - Andras Eke
- Institute of Translational Medicine, Semmelweis University, Hungary
- Department of Physiology, Semmelweis University, Hungary
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Jackson WF. Introduction to ion channels and calcium signaling in the microcirculation. CURRENT TOPICS IN MEMBRANES 2020; 85:1-18. [PMID: 32402636 DOI: 10.1016/bs.ctm.2020.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The microcirculation is the network of feed arteries, arterioles, capillaries and venules that supply and drain blood from every tissue and organ in the body. It is here that exchange of heat, oxygen, carbon dioxide, nutrients, hormones, water, cytokines, and immune cells takes place; essential functions necessary to maintenance of homeostasis throughout the life span. This chapter will outline the structure and function of each microvascular segment highlighting the critical roles played by ion channels in the microcirculation. Feed arteries upstream from the true microcirculation and arterioles within the microcirculation contribute to systemic vascular resistance and blood pressure control. They also control total blood flow to the downstream microcirculation with arterioles being responsible for distribution of blood flow within a tissue or organ dependent on the metabolic needs of the tissue. Terminal arterioles control blood flow and blood pressure to capillary units, the primary site of diffusional exchange between blood and tissues due to their large surface area. Venules collect blood from capillaries and are important sites for fluid exchange and immune cell trafficking. Ion channels in microvascular smooth muscle cells, endothelial cells and pericytes importantly contribute to all of these functions through generation of intracellular Ca2+ and membrane potential signals in these cells.
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Affiliation(s)
- William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States.
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Wildeboer RR, Van Sloun RJG, Schalk SG, Mannaerts CK, Van Der Linden JC, Huang P, Wijkstra H, Mischi M. Convective-Dispersion Modeling in 3D Contrast-Ultrasound Imaging for the Localization of Prostate Cancer. IEEE TRANSACTIONS ON MEDICAL IMAGING 2018; 37:2593-2602. [PMID: 29993539 DOI: 10.1109/tmi.2018.2843396] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Despite being the solid tumor with the highest incidence in western men, prostate cancer (PCa) still lacks reliable imaging solutions that can overcome the need for systematic biopsies. Dynamic contrast-enhanced ultrasound imaging (DCE-US) allows us to quantitatively characterize the vascular bed in the prostate, due to its ability to visualize an intravenously administered bolus of contrast agents. Previous research has demonstrated that DCE-US parameters related to the vascular architecture are useful markers for the localization of PCa lesions. In this paper, we propose a novel method to assess the convective dispersion (D) and velocity (v) of the contrast bolus spreading through the prostate from three-dimensional (3D) DCE-US recordings. By assuming that D and v are locally constant, we solve the convective-dispersion equation by minimizing the corresponding regularized least-squares problem. 3D multiparametric maps of D and v were compared with 3D histopathology retrieved from the radical prostatectomy specimens of six patients. With a pixel-wise area under the receiver operating characteristic curve of 0.72 and 0.80, respectively, the method shows diagnostic value for the localization of PCa.
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Pries AR, Secomb TW. Making microvascular networks work: angiogenesis, remodeling, and pruning. Physiology (Bethesda) 2015; 29:446-55. [PMID: 25362638 DOI: 10.1152/physiol.00012.2014] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The adequate and efficient functioning of the microcirculation requires not only numerous vessels providing a large surface area for transport but also a structure that provides short diffusion distances from capillaries to tissue and efficient distribution of convective blood flow. Theoretical models show how a combination of angiogenesis, remodeling, and pruning in response to hemodynamic and metabolic stimuli, termed "angioadaptation," generates well organized, functional networks.
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Affiliation(s)
- Axel R Pries
- Department of Physiology and CCR, Charité, Berlin, Germany; Deutsches Herzzentrum Berlin, Berlin, Germany;
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, Arizona
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Mouridsen K, Hansen MB, Østergaard L, Jespersen SN. Reliable estimation of capillary transit time distributions using DSC-MRI. J Cereb Blood Flow Metab 2014; 34:1511-21. [PMID: 24938401 PMCID: PMC4158667 DOI: 10.1038/jcbfm.2014.111] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 05/23/2014] [Accepted: 05/25/2014] [Indexed: 11/09/2022]
Abstract
The regional availability of oxygen in brain tissue is traditionally inferred from the magnitude of cerebral blood flow (CBF) and the concentration of oxygen in arterial blood. Measurements of CBF are therefore widely used in the localization of neuronal response to stimulation and in the evaluation of patients suspected of acute ischemic stroke or flow-limiting carotid stenosis. It was recently demonstrated that capillary transit time heterogeneity (CTH) limits maximum oxygen extraction fraction (OEF(max)) that can be achieved for a given CBF. Here we present a statistical approach for determining CTH, mean transit time (MTT), and CBF using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI). Using numerical simulations, we demonstrate that CTH, MTT, and OEF(max) can be estimated with low bias and variance across a wide range of microvascular flow patterns, even at modest signal-to-noise ratios. Mean transit time estimated by singular value decomposition (SVD) deconvolution, however, is confounded by CTH. The proposed technique readily identifies malperfused tissue in acute stroke patients and appears to highlight information not detected by the standard SVD technique. We speculate that this technique permits the non-invasive detection of tissue with impaired oxygen delivery in neurologic disorders such as acute ischemic stroke and Alzheimer's disease during routine diagnostic imaging.
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Affiliation(s)
- Kim Mouridsen
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Mikkel Bo Hansen
- Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Leif Østergaard
- 1] Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark [2] Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark
| | - Sune Nørhøj Jespersen
- 1] Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark [2] Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
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