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Adam M, Lindén J, Raekallio M, Meller A, Mannerström B, Abu-Shahba A, Seppänen-Kaijansinkko R, Salla K. Effects of vatinoxan on xylazine-induced pulmonary alterations in sheep. J Vet Pharmacol Ther 2021; 45:117-125. [PMID: 34478172 DOI: 10.1111/jvp.13013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 07/20/2021] [Accepted: 08/24/2021] [Indexed: 11/30/2022]
Abstract
It was hypothesized that premedication with vatinoxan, a peripheral α2 -adrenoceptor antagonist, would mitigate xylazine-induced pulmonary alterations in sheep. Fourteen adult sheep were allotted into two equal groups and premedicated with either vatinoxan (750 µg/kg IV) or saline and sedated 10 min later with xylazine (500 µg/kg IV). Arterial oxygen saturation (SpO2 ) was measured and respiratory rate (RR) counted at intervals. The sheep were euthanized with IV pentobarbital 10 min after xylazine administration. The severity of pulmonary parenchymal alterations was assessed and graded grossly and histologically and correlations of the morphological changes with SpO2 evaluated. Following xylazine injection, SpO2 was significantly higher and RR significantly lower with vatinoxan than with saline and the sheep administered vatinoxan exhibited significantly smaller quantities of tracheal foam than those receiving saline. No significant differences in macroscopic oedema scores were detected between treatments. In contrast, the vatinoxan-treated animals exhibited significantly graver microscopic interstitial alveolar oedema and haemorrhage than saline-treated animals. The histological severity scores did not correlate with changes in SpO2 . In conclusion, xylazine induced a marked reduction in SpO2 which was abolished by the prior administration of vatinoxan. The histologically detected alterations after pentobarbital euthanasia with vatinoxan premedication need to be studied further.
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Affiliation(s)
- Magdy Adam
- Department of Equine and Small Animal Medicine, Faculty of veterinary Medicine, University of Helsinki, Helsinki, Finland.,Pharmacology Department, Faculty of Veterinary Medicine, Beni-Suef University, Beni Suef, Egypt
| | - Jere Lindén
- Department of Veterinary Bioscience, Faculty of veterinary Medicine, University of Helsinki, Helsinki, Finland.,Finnish Centre for Laboratory Animal Pathology, HiLIFE, University of Helsinki, Helsinki, Finland
| | - Marja Raekallio
- Department of Equine and Small Animal Medicine, Faculty of veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Anna Meller
- Laboratory Animal Centre, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Bettina Mannerström
- Department of Oral and Maxillofacial Diseases, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Ahmed Abu-Shahba
- Department of Oral and Maxillofacial Diseases, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.,Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tanta University, Tanta, Egypt
| | - Riitta Seppänen-Kaijansinkko
- Department of Oral and Maxillofacial Diseases, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Kati Salla
- Department of Equine and Small Animal Medicine, Faculty of veterinary Medicine, University of Helsinki, Helsinki, Finland
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Conhaim RL, Watson KE, Broytman O, Teodorescu M. Apnea causes microvascular perfusion maldistribution in isolated rat lungs. Physiol Rep 2019; 7:e14085. [PMID: 31054186 PMCID: PMC6499865 DOI: 10.14814/phy2.14085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/04/2019] [Accepted: 04/10/2019] [Indexed: 11/24/2022] Open
Abstract
Obstructive sleep apnea is associated with significant cardiovascular disease, yet little is known about the effects of OSA on pulmonary microvascular perfusion. In a recent report, we showed that pulmonary microvascular perfusion was significantly mal-distributed in anesthetized, spontaneously breathing rats exposed to five episodes of obstructive apnea. We quantified microvascular perfusion by analyzing trapping patterns of 4 μm diameter fluorescent latex particles infused into the pulmonary circulation after the last episode. We could not determine if the perfusion maldistribution was due to the effects of large subatmospheric intrapleural pressures during apnea, or to precapillary OSA hypoxic vasoconstriction. To address this, we repeated these studies using isolated, buffer-perfused rat lungs (Ppulm art , 10 cm H2 O) ventilated in a chamber (-5 to -15 cm H2 O, 25 breaths/min; Ptrachea = 0). We simulated apnea by clamping the trachea and cycling the chamber pressures between -25 and -35 cm H2 O for five breaths. After five apnea episodes, we infused 4 μm diam. fluorescent latex particles into the pulmonary artery. The number of particles recovered from the venous effluent was 74% greater in nonapneic isolated lungs compared to apneic lungs (P ≤ 0.05). Apneic lungs also had perfusion maldistributions that were 73% greater than those without apnea (P ≤ 0.05). We conclude that simulated apnea in isolated, perfused rat lungs produces significantly greater particle trapping and microvascular perfusion maldistribution than in nonapneic isolated lungs. We believe these effects are due to the large, negative intrapleural pressures produced during apnea, and are not due to hypoxia.
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Affiliation(s)
- Robert L Conhaim
- The William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin.,Department of Surgery, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Kal E Watson
- The William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Oleg Broytman
- The William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Mihaela Teodorescu
- The William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin.,Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
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Conhaim RL, Segal GS, Watson KE. Arterio-venous anastomoses in isolated, perfused rat lungs. Physiol Rep 2016; 4:4/21/e13023. [PMID: 27821718 PMCID: PMC5112501 DOI: 10.14814/phy2.13023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 10/03/2016] [Accepted: 10/09/2016] [Indexed: 11/24/2022] Open
Abstract
Several studies have suggested that large-diameter (>25 μm) arterio-venous shunt pathways exist in the lungs of rats, dogs, and humans. We investigated the nature of these pathways by infusing specific-diameter fluorescent latex particles (4, 7, 15, 30, or 50 μm) into isolated, ventilated rat lungs perfused at constant pressure. All lungs received the same mass of latex (5 mg), which resulted in infused particle numbers that ranged from 1.7 × 107 4 μm particles to 7.5 × 104 50 μm particles. Particles were infused over 2 min. We used a flow cytometer to count particle appearances in venous effluent samples collected every 0.5 min for 12 min from the start of particle infusion. Cumulative percentages of infused particles that appeared in the samples averaged 3.17 ± 2.46% for 4 μm diameter particles, but ranged from 0.01% to 0.17% for larger particles. Appearances of 4 μm particles followed a rapid upslope beginning at 30 sec followed by a more gradual downslope that lasted for up to 12 min. All other particle diameters also began to appear at 30 sec, but followed highly irregular time courses. Infusion of 7 and 15 μm particles caused transient but significant perfusate flow reductions, while infusion of all other diameters caused insignificant reductions in flow. We conclude that small numbers of bypass vessels exist that can accommodate particle diameters of 7-to-50 μm. We further conclude that our 4 μm particle data are consistent with a well-developed network of serial and parallel perfusion pathways at the acinar level.
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Affiliation(s)
- Robert L Conhaim
- The William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin .,Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Gilad S Segal
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| | - Kal E Watson
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
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Wu JX, Zhu HW, Chen X, Wei JL, Zhang XF, Xu MY. Inducible nitric oxide synthase inhibition reverses pulmonary arterial dysfunction in lung transplantation. Inflamm Res 2014; 63:609-18. [PMID: 24760104 DOI: 10.1007/s00011-014-0733-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 03/30/2014] [Accepted: 03/31/2014] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Ischemia-reperfusion injury (IRI) after lung transplantation remains a significant cause of morbidity and mortality. Lung IRI induces nitric oxide synthesis (iNOS) and reactive nitrogen species, decreasing nitric oxide bioavailability. We hypothesized that ischemia-induced iNOS intensifies with reperfusion and contributes to IRI-induced pulmonary arterial regulatory dysfunction, which may lead to early graft failure and cause pulmonary edema. The aim of this study was to determine whether ischemia-reperfusion alters inducible and endothelial nitric oxide synthase expression, potentially affecting pulmonary perfusion. We further evaluated the role of iNOS in post-transplantation pulmonary arterial disorder. METHODS We randomized 32 Sprague-Dawley rats into two groups. The control group was given a sham operation whilst the experimental group received orthotropic lung transplants with a modified three-cuff technique. Changes in lung iNOS, and endothelial nitric oxide synthase expression were measured after lung transplantation by enzyme-linked immunosorbent assay (ELISA). Vasoconstriction in response to exogenous phenylephrine and vasodilation in response to exogenous acetylcholine of pulmonary arterial rings were measured in vitro as a measure of vascular dysfunction. To elucidate the roles of iNOS in regulating vascular function, an iNOS activity inhibitor (N6-(1-iminoethyl)-L-lysine, L-NIL) was used to treat isolated arterial rings. In order to test whether iNOS inhibition has a therapeutic effect, we further used L-NIL to pre-treat transplanted lungs and then measured post-transplantation arterial responses. RESULTS Lung transplantation caused upregulation of iNOS expression. This was also accompanied by suppression of both vasoconstriction and vasodilation of arterial rings from transplanted lungs. Removal of endothelium did not interfere with the contraction of pulmonary arterial rings from transplanted lungs. In contrast, iNOS inhibition rescued the vasoconstriction response to exogenous phenylephrine of pulmonary arterial rings from transplanted lungs. In addition, lung transplantation led to suppression of PaO2/FiO2 ratio, increased intrapulmonary shunt (Q s/Q t), and increase of lung wet to dry ratio (W/D), malondialdehyde and myeloperoxidase levels, all of which were reversed upon iNOS inhibition. Furthermore, inhibition of iNOS significantly rescued vascular function and alleviated edema and inflammatory cell infiltration in the transplanted lung. CONCLUSIONS Our data suggest that lung transplantation causes upregulation of iNOS expression, and pulmonary vascular dysfunction. iNOS inhibition reverses the post-transplantational pulmonary vascular dysfunction.
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Affiliation(s)
- Jing-Xiang Wu
- Department of Anesthesiology, Shanghai Chest Hospital, Shanghai Jiaotong University, 241 West Huaihai Road, Shanghai, 200030, People's Republic of China
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Abstract
Hypoxic pulmonary vasoconstriction (HPV) continues to fascinate cardiopulmonary physiologists and clinicians since its definitive description in 1946. Hypoxic vasoconstriction exists in all vertebrate gas exchanging organs. This fundamental response of the pulmonary vasculature in air breathing animals has relevance to successful fetal transition to air breathing at birth and as a mechanism of ventilation-perfusion matching in health and disease. It is a complex process intrinsic to the vascular smooth muscle, but with in vivo modulation by a host of factors including the vascular endothelium, erythrocytes, pulmonary innervation, circulating hormones and acid-base status to name only a few. This review will provide a broad overview of HPV and its mechansms and discuss the advantages and disadvantages of HPV in normal physiology, disease and high altitude.
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Affiliation(s)
- Erik R Swenson
- Department of Medicine, University of Washington, VA Puget Sound Health Care System, Seattle, WA 98108, USA.
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Martinot JB, Mulè M, de Bisschop C, Overbeek MJ, Le-Dong NN, Naeije R, Guénard H. Lung membrane conductance and capillary volume derived from the NO and CO transfer in high-altitude newcomers. J Appl Physiol (1985) 2013; 115:157-66. [DOI: 10.1152/japplphysiol.01455.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Acute exposure to high altitude may induce changes in carbon monoxide (CO) membrane conductance (DmCO) and capillary lung volume (Vc). Measurements were performed in 25 lowlanders at Brussels (D0), at 4,300 m after a 2- or 3-day exposure (D2,3) without preceding climbing, and 5 days later (D7,8), before and after an exercise test, under a trial with two arterial pulmonary vasodilators or a placebo. The nitric oxide (NO)/CO transfer method was used, assuming both infinite and finite values to the NO blood conductance (θNO). Doppler echocardiography provided hemodynamic data. Compared with sea level, lung diffusing capacity for CO increased by 24% at D2,3 and is returned to control at D7,8. The acute increase in lung diffusing capacity for CO resulted from increases in DmCO and Vc with finite and infinite θNO assumptions. The alveolar volume increased by 16% at D2,3 and normalized at D7,8. The mean increase in systolic arterial pulmonary pressure at rest at D2,3 was minimal. In conclusion, the acute increase in Vc may be related to the increase in alveolar volume and to the increase in capillary pressure. Compared with the infinite θNO value, the use of a finite θNO value led to about a twofold increase in DmCO value and to a persistent increase in DmCO at D7,8 compared with D0. After exercise, DmCO decreased slightly less in subjects treated by the vasodilators, suggesting a beneficial effect on interstitial edema.
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Affiliation(s)
| | | | - Claire de Bisschop
- Laboratory Mobilité Vieillissement Exercice (MOVE), Poitiers University, Poitiers, France
| | - Maria J. Overbeek
- Department of Pulmonology, Medical Center Haaglanden, the Hague, the Netherlands
| | - Nhat-Nam Le-Dong
- Service de Physiologie, Explorations Fonctionnelles, Hôpital Cochin, Paris, France
| | - Robert Naeije
- Laboratory of Physiology, Faculty of Medicine, Free University of Brussels, Brussels, Belgium; and
| | - Hervé Guénard
- Department of Physiology, University Hospital Bordeaux 2, Bordeaux, France
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