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Graziosi A, Perrotta M, Russo D, Gasparroni G, D’Egidio C, Marinelli B, Di Marzio G, Falconio G, Mastropasqua L, Li Volti G, Mangifesta R, Gazzolo D. Oxidative Stress Markers and the Retinopathy of Prematurity. J Clin Med 2020; 9:jcm9092711. [PMID: 32825796 PMCID: PMC7563779 DOI: 10.3390/jcm9092711] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/07/2020] [Accepted: 08/11/2020] [Indexed: 12/15/2022] Open
Abstract
Retinopathy of prematurity (ROP) is a leading cause of potentially preventable blindness in low birth weight preterm infants. Several perinatal and postnatal factors contribute to the incomplete maturation of retinal vascularization, leading to oxidative stress damage. Literature data suggest that the lack of equilibrium between pro-oxidants and anti-oxidants plays a key role. In the last decade, there has been an increasing interest in identifying the antecedents of ROP and the relevant pathogenic mechanisms involved. In this context, a panel of biomarkers was investigated in order to achieve early detection of oxidative stress occurrence and to prevent retinal damage. Several nutritional elements have been found to play a relevant role in ROP prevention. At this stage, no conclusive data have been shown to support the usefulness of one biomarker over another. Recently, the Food and Drugs Administration, the European Medicine Agency, and the National Institute of Health proposed a series of criteria in order to promote the inclusion of new biomarkers in perinatal clinical guidelines and daily practice. The aim of the present review is to offer an update on a panel of biomarkers, currently investigated as potential predictors of ROP, highlighting their strengths and weaknesses.
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Affiliation(s)
- Alessandro Graziosi
- Neonatal Intensive Unit Care, University “G. d’Annunzio” Chieti-Pescara, 66100 Chieti, Italy; (A.G.); (M.P.); (D.R.); (G.G.); (C.D.)
- Department of Paediatrics, University “G. d’ Annunzio” Chieti-Pescara, 66100 Chieti, Italy
| | - Marika Perrotta
- Neonatal Intensive Unit Care, University “G. d’Annunzio” Chieti-Pescara, 66100 Chieti, Italy; (A.G.); (M.P.); (D.R.); (G.G.); (C.D.)
- Department of Paediatrics, University “G. d’ Annunzio” Chieti-Pescara, 66100 Chieti, Italy
| | - Daniele Russo
- Neonatal Intensive Unit Care, University “G. d’Annunzio” Chieti-Pescara, 66100 Chieti, Italy; (A.G.); (M.P.); (D.R.); (G.G.); (C.D.)
- Department of Paediatrics, University “G. d’ Annunzio” Chieti-Pescara, 66100 Chieti, Italy
| | - Giorgia Gasparroni
- Neonatal Intensive Unit Care, University “G. d’Annunzio” Chieti-Pescara, 66100 Chieti, Italy; (A.G.); (M.P.); (D.R.); (G.G.); (C.D.)
- Department of Paediatrics, University “G. d’ Annunzio” Chieti-Pescara, 66100 Chieti, Italy
| | - Claudia D’Egidio
- Neonatal Intensive Unit Care, University “G. d’Annunzio” Chieti-Pescara, 66100 Chieti, Italy; (A.G.); (M.P.); (D.R.); (G.G.); (C.D.)
| | | | - Guido Di Marzio
- Department of Ophthalmology, University “G. D’ Annunzio” Chieti-Pescara, 66100 Chieti, Italy; (G.D.M.); (G.F.); (L.M.)
| | - Gennaro Falconio
- Department of Ophthalmology, University “G. D’ Annunzio” Chieti-Pescara, 66100 Chieti, Italy; (G.D.M.); (G.F.); (L.M.)
| | - Leonardo Mastropasqua
- Department of Ophthalmology, University “G. D’ Annunzio” Chieti-Pescara, 66100 Chieti, Italy; (G.D.M.); (G.F.); (L.M.)
| | - Giovanni Li Volti
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95100 Catania, Italy;
| | | | - Diego Gazzolo
- Neonatal Intensive Unit Care, University “G. d’Annunzio” Chieti-Pescara, 66100 Chieti, Italy; (A.G.); (M.P.); (D.R.); (G.G.); (C.D.)
- Correspondence: ; Tel.: +39-0871-358221
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Zhang HB, Wang XD, Xu K, Li XG. The progress of prophylactic treatment in retinopathy of prematurity. Int J Ophthalmol 2018; 11:858-873. [PMID: 29862189 DOI: 10.18240/ijo.2018.05.24] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 09/28/2017] [Indexed: 12/19/2022] Open
Abstract
Retinopathy of prematurity (ROP) is a retinal vascular disorder frequently found in premature infants. Different therapeutic strategies have been developed to treat ROP. However, there are still many children with ROP suffering by severe limitations in vision or even blindness. Recently, ROP has been suggested to be caused by abnormal development of the retinal vasculature, but not simply resulted by retinal neovascularization which takes about 4 to 6wk after birth in premature infants. Thus, instead of focusing on how to reduce retinal neovascularization, understanding the pathological changes and mechanisms that occur prior to retinal neovascularization is meaningful, which may lead to identify novel target(s) for the development of novel strategy to promote the healthy growth of retinal blood vessels rather than passively waiting for the appearance of retinal neovascularization and removing it by force. In this review, we discussed recent studies about, 1) the pathogenesis prior to retinal neovascularization in oxygen-induced retinopathy (OIR; a ROP in animal model) and in premature infants with ROP; 2) the preclinical and clinical research on preventive treatment of early OIR and ROP. We will not only highlight the importance of the mechanisms and signalling pathways in regulating early stage of ROP but also will provide guidance for actively exploring novel mechanisms and discovering novel treatments for early phase OIR and ROP prior to retinal neovascularization in the future.
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Affiliation(s)
- Hong-Bing Zhang
- Eye Institute of Shaanxi Province; Xi'an First Hospital, Xi'an 710002, Shaanxi Province, China
| | - Xiao-Dong Wang
- Eye Institute of Shaanxi Province; Xi'an First Hospital, Xi'an 710002, Shaanxi Province, China
| | - Kun Xu
- Eye Institute of Shaanxi Province; Xi'an First Hospital, Xi'an 710002, Shaanxi Province, China
| | - Xiao-Gang Li
- Department of Internal Medicine; Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Honoré JC, Kooli A, Hamel D, Alquier T, Rivera JC, Quiniou C, Hou X, Kermorvant-Duchemin E, Hardy P, Poitout V, Chemtob S. Fatty acid receptor Gpr40 mediates neuromicrovascular degeneration induced by transarachidonic acids in rodents. Arterioscler Thromb Vasc Biol 2013; 33:954-61. [PMID: 23520164 DOI: 10.1161/atvbaha.112.300943] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Nitro-oxidative stress exerts a significant role in the genesis of hypoxic-ischemic (HI) brain injury. We previously reported that the ω-6 long chain fatty acids, transarachidonic acids (TAAs), which are nitrative stress-induced nonenzymatically generated arachidonic acid derivatives, trigger selective microvascular endothelial cell death in neonatal neural tissue. The primary molecular target of TAAs remains unidentified. GPR40 is a G protein-coupled receptor activated by long chain fatty acids, including ω-6; it is highly expressed in brain, but its functions in this tissue are largely unknown. We hypothesized that TAAs play a significant role in neonatal HI-induced cerebral microvascular degeneration through GPR40 activation. APPROACH AND RESULTS Within 24 hours of a HI insult to postnatal day 7 rat pups, a cerebral infarct and a 40% decrease in cerebrovascular density was observed. These effects were associated with an increase in nitrative stress markers (3-nitrotyrosine immunoreactivity and TAA levels) and were reduced by treatment with nitric oxide synthase inhibitor. GPR40 was expressed in rat pup brain microvasculature. In vitro, in GPR40-expressing human embryonic kidney (HEK)-293 cells, [(14)C]-14E-AA (radiolabeled TAA) bound specifically, and TAA induced calcium transients, extracellular signal-regulated kinase 1/2 phosphorylation, and proapoptotic thrombospondin-1 expression. In vivo, intracerebroventricular injection of TAAs triggered thrombospondin-1 expression and cerebral microvascular degeneration in wild-type mice, but not in GPR40-null congeners. Additionally, HI-induced neurovascular degeneration and cerebral infarct were decreased in GPR40-null mice. CONCLUSIONS GPR40 emerges as the first identified G protein-coupled receptor conveying actions of nonenzymatically generated nitro-oxidative products, specifically TAAs, and is involved in (neonatal) HI encephalopathy.
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Affiliation(s)
- Jean-Claude Honoré
- Department of Pediatrics, Research Center-CHU Ste-Justine, Montréal, Quebec, Canada
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Kermorvant-Duchemin E, Sennlaub F, Behar-Cohen F, Chemtob S. Épidémiologie et physiopathologie de la rétinopathie du prématuré. Arch Pediatr 2011; 18 Suppl 2:S79-85. [DOI: 10.1016/s0929-693x(11)71095-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Rivera JC, Sapieha P, Joyal JS, Duhamel F, Shao Z, Sitaras N, Picard E, Zhou E, Lachapelle P, Chemtob S. Understanding retinopathy of prematurity: update on pathogenesis. Neonatology 2011; 100:343-53. [PMID: 21968165 DOI: 10.1159/000330174] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Retinopathy of prematurity (ROP), an ocular disease characterized by the onset of vascular abnormalities in the developing retina, is the major cause of visual impairment and blindness in premature neonates. ROP is a complex condition in which various factors participate at different stages of the disease leading to microvascular degeneration followed by neovascularization, which in turn predisposes to retinal detachment. Current ablative therapies (cryotherapy and laser photocoagulation) used in the clinic for the treatment of ROP have limitations and patients can still have long-term effects even after successful treatment. New treatment modalities are still emerging. The most promising are the therapies directed against VEGF; more recently the use of preventive dietary supplementation with ω-3 polyunsaturated fatty acid may also be promising. Other than pharmacologic and nutritional approaches, cell-based strategies for vascular repair are likely to arise from advances in regenerative medicine using stem cells. In addition to all of these, a greater understanding of other factors involved in regulating pathologic retinal angiogenesis continues to emerge, suggesting potential targets for therapeutic approaches. This review summarizes an update on the current state of knowledge on ROP from our and other laboratories, with particular focus on the role of nitro-oxidative stress and notably trans-arachidonic acids in microvascular degeneration, semaphorin 3 operating as vasorepulsive molecules in the avascular hypoxic retina and in turn impairing revascularization, succinate and its receptor GPR91 in neuron-mediated retinal neovascularization, and ω-3 lipids as modulators of preretinal neovascularization.
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Affiliation(s)
- José Carlos Rivera
- Department of Pediatrics, Ophthalmology and Pharmacology, Centre Hospitalier Universitaire Sainte-Justine Research Center, Montréal, Qué., Canada
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Honoré JC, Kooli A, Hou X, Hamel D, Rivera JC, Picard É, Hardy P, Tremblay S, Varma DR, Jankov RP, Mancini JA, Balazy M, Chemtob S. Sustained hypercapnia induces cerebral microvascular degeneration in the immature brain through induction of nitrative stress. Am J Physiol Regul Integr Comp Physiol 2010; 298:R1522-30. [DOI: 10.1152/ajpregu.00807.2009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Hypercapnia is regularly observed in chronic lung disease, such as bronchopulmonary dysplasia in preterm infants. Hypercapnia results in increased nitric oxide synthase activity and in vitro formation of nitrates. Neural vasculature of the immature subject is particularly sensitive to nitrative stress. We investigated whether exposure to clinically relevant sustained high CO2 causes microvascular degeneration in the newborn brain by inducing nitrative stress, and whether this microvascular degeneration has an impact on brain growth. Newborn rat pups were exposed to 10% CO2 as inspired gas (PaCO2 = 60–70 mmHg) starting within 24 h of birth until postnatal day 7 (P7). Brains were notably collected at different time points to measure vascular density, determine brain cortical nitrite/nitrate, and trans-arachidonic acids (TAAs; products of nitration) levels as effectors of vessel damage. Chronic exposure of rat pups to high CO2 (PaCO2 ≈ 65 mmHg) induced a 20% loss in cerebrovascular density at P3 and a 15% decrease in brain mass at P7; at P30, brain mass remained lower in CO2-exposed animals. Within 24 h of exposure to CO2, brain eNOS expression and production of nitrite/nitrate doubled, lipid nitration products (TAAs) increased, and protein nitration (3-nitrotyrosine immunoreactivity) was also coincidently augmented on brain microvessels (lectin positive). Intracerebroventricular injection of TAAs (10 μM) replicated cerebrovascular degeneration. Treatment of rat pups with NOS inhibitor (l-Nω-nitroarginine methyl ester) or a peroxynitrite decomposition catalyst (FeTPPS) prevented hypercapnia-induced microvascular degeneration and preserved brain mass. Cytotoxic effects of high CO2 were reproduced in vitro /ex vivo on cultured endothelial cells and sprouting microvessels. In summary, hypercapnia at values frequently observed in preterm infants with chronic lung disease results in increased nitrative stress, which leads to cerebral cortical microvascular degeneration and curtails brain growth.
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Affiliation(s)
- Jean-Claude Honoré
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology, Université de Montréal, Quebec, Canada
| | - Amna Kooli
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec, Canada
| | - Xin Hou
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
| | - David Hamel
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology, Université de Montréal, Quebec, Canada
| | - José Carlos Rivera
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology, Université de Montréal, Quebec, Canada
| | - Émilie Picard
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology, Université de Montréal, Quebec, Canada
| | - Pierre Hardy
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology, Université de Montréal, Quebec, Canada
| | - Sophie Tremblay
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
| | - Daya R. Varma
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec, Canada
| | - Robert P. Jankov
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada; and
| | - Joseph A. Mancini
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
| | - Michael Balazy
- Department of Pathology, New York Medical College, New York, New York
| | - Sylvain Chemtob
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology, Université de Montréal, Quebec, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec, Canada
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MacCarrick MJ, Torbati D, Kimura D, Raszynski A, Zeng W, Totapally BR. Does hypercapnia ameliorate hyperoxia-induced lung injury in neonatal rats? Lung 2009; 188:235-40. [PMID: 20033196 DOI: 10.1007/s00408-009-9211-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 11/29/2009] [Indexed: 12/28/2022]
Abstract
Therapeutic hypercapnia (TH), an intentional inhalation of CO(2), has been shown to improve pulmonary function in certain models of lung injury. We tested the null hypothesis that TH does not improve hyperoxic lung injury in neonatal rats. The prospective, randomized study was set at Research laboratory in Children's Hospital. Forty-five newborn rats were randomly assigned to three groups (n = 15/group), and exposed to 96 h of normoxia (FiO(2) = 0.21), hyperoxia (FiO(2) > 0.98), and TH (FiO(2) = 0.95, FiCO(2) = 0.05). Lung histology, wet-weight to dry-weight ratio, and concentrations of pro- and anti-inflammatory cytokines (IL-1beta, IL-6, TNF-alpha, and IL-10) were used to evaluate pulmonary damage. Using a scale of 0-4, the total scores for lungs hypercellularity, inflammation, and hemorrhage was significantly increased from a median value of 1.5 in normoxia to 2.5 in hyperoxia (P < 0.05) and 3.0 with TH (P < 0.001, nonparametric ANOVA). The interstitial space relative to the alveolar space, as a measure of hypercellularity, was increased by 18% during hyperoxia and by 44% with TH compared with normoxia. TH significantly increased the size of the interstitial space by 22% compared with hyperoxia (P < 0.001). The lung wet-weight to dry-weight ratio was increased by 10% in both hyperoxic groups (P < 0.001). Both hyperoxic groups showed significant reductions in the concentration of IL-1beta compared with normoxia (P < 0.001), whereas the ratio of IL-1beta to IL-10 was significantly decreased, indicating an anti-inflammatory trend. TH does not prevent histological manifestations of hyperoxic lung injury in spontaneously breathing neonatal rats and may worsen the outcome.
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Affiliation(s)
- Matthew J MacCarrick
- Division of Critical Care Medicine, Miami Children's Hospital, 3100 SW 62nd Avenue, Miami, FL 33155, USA
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Ischemia’s Proliferative and Morphological Effects: Analyzing the Roles of Hypoxia, Hypercapnia, and Glucose. Cell Mol Bioeng 2009. [DOI: 10.1007/s12195-009-0098-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Understanding ischemic retinopathies: emerging concepts from oxygen-induced retinopathy. Doc Ophthalmol 2009; 120:51-60. [DOI: 10.1007/s10633-009-9201-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Accepted: 10/12/2009] [Indexed: 01/08/2023]
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Connor KM, Krah NM, Dennison RJ, Aderman CM, Chen J, Guerin KI, Sapieha P, Stahl A, Willett KL, Smith LEH. Quantification of oxygen-induced retinopathy in the mouse: a model of vessel loss, vessel regrowth and pathological angiogenesis. Nat Protoc 2009; 4:1565-73. [PMID: 19816419 DOI: 10.1038/nprot.2009.187] [Citation(s) in RCA: 516] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The mouse model of oxygen-induced retinopathy (OIR) has been widely used in studies related to retinopathy of prematurity, proliferative diabetic retinopathy and in studies evaluating the efficacy of antiangiogenic compounds. In this model, 7-d-old (P7) mouse pups with nursing mothers are subjected to hyperoxia (75% oxygen) for 5 d, which inhibits retinal vessel growth and causes significant vessel loss. On P12, mice are returned to room air and the hypoxic avascular retina triggers both normal vessel regrowth and retinal neovascularization (NV), which is maximal at P17. Neovascularization spontaneously regresses between P17 and P25. Although the OIR model has been the cornerstone of studies investigating proliferative retinopathies, there is currently no harmonized protocol to assess aspects of angiogenesis and treatment outcome. In this protocol we describe standards for mouse size, sample size, retinal preparation, quantification of vascular loss, vascular regrowth, NV and neovascular regression.
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Affiliation(s)
- Kip M Connor
- Department of Ophthalmology, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts, USA
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Belik J, Stevens D, Pan J, Shehnaz D, Ibrahim C, Kantores C, Ivanovska J, Grasemann H, Jankov RP. Chronic hypercapnia downregulates arginase expression and activity and increases pulmonary arterial smooth muscle relaxation in the newborn rat. Am J Physiol Lung Cell Mol Physiol 2009; 297:L777-84. [PMID: 19666777 DOI: 10.1152/ajplung.00047.2009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
In rats, chronic hypercapnia has been reported to ameliorate hypoxia-induced pulmonary hypertension in newborn and adult and to enhance endothelium-dependent vasorelaxation in adult pulmonary arteries. The underlying mechanisms accounting for chronic hypercapnia-induced improvements in pulmonary vascular function are not understood. Hypothesizing that downregulation of arginase activity may be contributory, we examined relaxation responses and arginase activity and expression in pulmonary arteries from newborn rats that were exposed (from birth to 14 days) to either mild-to-moderate (5.5% inhaled CO(2)) or severe (10% CO(2)) hypercapnia with either normoxia or hypoxia (13% O(2)). Pulmonary arteries from pups exposed to normoxia and chronic hypercapnia (5.5 or 10% CO(2)) contracted less in response to a thromboxane A(2) analog, U-46619, and showed enhanced endothelium-dependent (but not independent) relaxation compared with arteries from normocapnic pups (P < 0.01). Parallel with these changes, arginase activity and arginase I (but not II) expression in lung and pulmonary arterial tissue were significantly decreased (P < 0.05). Exposure to 10% CO(2) significantly increased (P < 0.01) pulmonary arterial tissue nitric oxide (nitrite) generation. In pups chronically exposed to hypoxia (13% O(2)), severe hypercapnia (10% CO(2)) significantly (P < 0.05) enhanced endothelium-dependent relaxation, increased nitric oxide generation, and decreased arginase activity but not expression. We conclude that chronic hypercapnia-induced downregulation of lung arginase expression and/or activity may reduce pulmonary vascular resistance by enhancing nitric oxide generation and thus endothelium-dependent relaxation. This mechanism may explain some of the beneficial effects of chronic hypercapnia on experimental pulmonary hypertension.
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Affiliation(s)
- Jaques Belik
- Physiology and Experimental Medicine Program, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada M5G 1X8.
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12
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Abstract
UNLABELLED 'Permissive hypercapnia' is a familiar term in neonatal intensive care, given the widespread adoption of low-tidal-volume ventilation strategies applied with the goal of decreasing respiratory morbidity. Recent evidence suggesting that hypercapnic acidosis may itself have protective effects on the lung and other organs has led to the coining of a new phrase, 'therapeutic hypercapnia', which also encompasses the use of supplemental inspired CO(2). CONCLUSION Experimental evidence suggests that mild-moderate hypercapnia can improve tissue oxygenation and perfusion, which may ameliorate injury to the immature lung and brain. However, hypercapnia may also be associated with adverse outcomes, and the range of PaCO(2) levels that are both safe and effective for specific subsets of neonates has yet to be determined.
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Affiliation(s)
- Robert P Jankov
- Department of Paediatric, University of Toronto, Toronto, Ontario Canada.
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Jain K, Siddam A, Marathi A, Roy U, Falck JR, Balazy M. The mechanism of oleic acid nitration by *NO(2). Free Radic Biol Med 2008; 45:269-83. [PMID: 18457679 DOI: 10.1016/j.freeradbiomed.2008.04.015] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 03/31/2008] [Accepted: 04/03/2008] [Indexed: 12/27/2022]
Abstract
Fatty acid nitration is a recently discovered process that generates biologically active nitro lipids; however, its mechanism has not been fully characterized. For example, some structural details such as vinyl and allyl isomers of the nitro fatty acids have not been established. To characterize lipids that originated from a biomimetic reaction of *NO(2) with oleic acid, we synthesized several isomers of nitro oleic acids and studied their chromatography and mass spectra by various techniques of mass spectrometry. LC/MS analysis performed on a high resolution micro column detected molecular carboxylic anions of various oleic acid nitro isomers (NO(2)OA). Esterification of NO(2)OA with pentafluorobenzyl bromide and diisopropylethylamine as a catalyst produced a unique isoxazole ester derivative exclusively from allyl NO(2)OA isomers via dehydration of the nitro group at ambient temperatures. This new analytical procedure revealed that *NO(2) generated two vinyl and two allyl isomers of NO(2)OA. The vinyl isomers showed high regioselectivity with the 1.8:1 preference for the 10-NO(2)OA isomer that was absent among allylic isomers. The nitration also generated elaidic acid via cis-trans isomerization and diatereoisomers of vicinal nitro hydroxy, nitro keto and alpha-nitro epoxy stearic acids with high stereo and regioselectivity. Nitration of small unilamelar phospholipid vesicles resulted in several phospholipids containing nitro lipids and elaidic acid amenable to hydrolysis by phospholipase A(2).
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Affiliation(s)
- Kavita Jain
- New York Medical College, Valhalla, NY 10595, USA
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14
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Leduc M, Kermorvant-Duchemin E, Checchin D, Sennlaub F, Chemtob S. [Hypercapnia- and trans-arachidonic acid-induced retinal microvascular degeneration: implications in the genesis of retinopathy of prematurity]. Med Sci (Paris) 2008; 23:939-43. [PMID: 18021704 DOI: 10.1051/medsci/20072311939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
High oxygen tension is a major factor in the genesis of retinopathy of prematurity (ROP). However, clinical and experimental evidence also suggest a significant role for high levels of carbon dioxide (CO(2)). Hypercapnia is a facilitator of nitration in vitro, and nitrative stress is known to have an important role in microvascular degeneration leading to ischemia in conditions such as ROP. We hereby present evidence that prolonged exposure to CO(2) impairs developmental retinal neovascularisation through a mechanism involving increased endothelial nitric oxide synthase and induction of a nitrative stress; effects of hypercapnia are independent of its hyperaemic effects. Moreover, in a model of oxygen-induced retinopathy, we demonstrate that an in vivo nitrative stress associated with retinal vasoobliteration results in nitration of cis-arachidonic acids into trans-arachidonic acids (TAAs). TAAs act in turn as mediators of nitrative stress by causing microvascular degeneration by inducing expression of the anti-angiogenic factor thrombospondin-1. These recent findings establish a previously unexplored means by which hypercapnia hinders efficient neovascularisation and provide new insight into the molecular mechanisms of nitrative stress on microvascular injury involving TAA, therefore opening new therapeutic avenues in the management of nitrative stress disorders such as in ischemic retinopathies (of prematurity and of diabetes) and encephalopathies.
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Affiliation(s)
- Martin Leduc
- Départements de Pédiatrie, d'Ophtalmologie et de Pharmacologie, Centre de recherche, CHU Sainte-Justine, Montréal, Québec, H3T 1C5 Canada
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15
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Russ AL, Haberstroh KM, Rundell AE. Experimental strategies to improve in vitro models of renal ischemia. Exp Mol Pathol 2007; 83:143-59. [PMID: 17490640 DOI: 10.1016/j.yexmp.2007.03.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 03/15/2007] [Accepted: 03/15/2007] [Indexed: 12/11/2022]
Abstract
Ischemia has elicited a great deal of interest among the scientific community due to its role in life-threatening pathologies such as cancer, stroke, acute renal failure, and myocardial infarction. Oxygen deprivation (hypoxia) associated with ischemia has recently become a subject of intense scrutiny. New investigators may find it challenging to induce hypoxic injury in vitro. Researchers may not always be aware of the experimental barriers that contribute to this phenomenon. Furthermore, ischemia is associated with other major insults, such as excess carbon dioxide (hypercapnia), nutrient deprivation, and accumulation of cellular wastes. Ideally, these conditions should also be incorporated into in vitro models. Therefore, the motivation behind this review is to: i. delineate major in vivo ischemic insults; ii. identify and explain critical in vitro parameters that need to be considered when simulating ischemic pathologies; iii. provide recommendations to improve experiments; and as a result, iv. enhance the validity of in vitro results for understanding clinical ischemic pathologies. Undoubtedly, it is not possible to completely replicate the in vivo environment in an ex vivo model system. In fact, the primary goal of many in vitro studies is to elucidate the role of specific stimuli during in vivo pathological events. This review will present methodologies that may be implemented to improve the applicability of in vitro models for understanding the complex pathological mechanisms of ischemia. Finally, although these topics will be discussed within the context of renal ischemia, many are pertinent for cellular models of other organ systems and pathologies.
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Affiliation(s)
- Alissa L Russ
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Intramural Dr. West Lafayette, IN 47907-1791, USA
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Leduc M, Kermorvant-Duchemin E, Checchin D, Sennlaub F, Sirinyan M, Kooli A, Lachapelle P, Chemtob S. Hypercapnia- and trans-arachidonic acid-induced retinal microvascular degeneration: implications in the genesis of retinopathy of prematurity. Semin Perinatol 2006; 30:129-38. [PMID: 16813971 DOI: 10.1053/j.semperi.2006.04.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
High oxygen tension is a major factor in the genesis of retinopathy of prematurity (ROP). However, clinical and experimental evidence suggests a significant role for high carbon dioxide (CO(2)) tension as well. Along these lines, although ischemia is often considered to be synonymous with an oxygen deficit, it is also associated with a concomitant local elevation of CO(2) that can lead to impaired developmental and ischemic neovascularization. The mechanisms by which hypercapnia induces retinal microvascular degeneration, a critical step which precedes the subsequent proliferative preretinal neovascularization, are not known. Nitrative stress has an important role in microvascular degeneration leading to ischemia in conditions such as ROP. Hypercapnia is a facilitator of nitration in vitro. We hereby present evidence that prolonged exposure to CO(2) impairs developmental retinal neovascularization through a mechanism involving increased endothelial nitric oxide synthase and induction of a nitrative stress; effects of hypercapnia are independent of its hyperaemic effects. Moreover, we demonstrate that an in vivo nitrative stress associated with retinal vasoobliteration results in nitration of arachidonic acids into trans-arachidonic acids (TAAs), which can act as mediators of nitrative stress by causing microvascular degeneration by inducing expression of the antiangiogenic factor thrombospondin-1. These recent findings establish a previously unexplored means by which hypercapnia hinders efficient neovascularization and provide new insight into the molecular mechanisms of nitrative stress on microvascular injury involving TAA, and suggest new therapeutic avenues in the management of nitrative stress disorders such as in ischemic retinopathies (of prematurity and of diabetes) and encephalopathies.
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Affiliation(s)
- Martin Leduc
- Department of Pediatrics, Ophthalmology and Pharmacology, Research Center, Hôpital Ste-Justine, 3175 Ch. Côte-Sainte-Catherine, Montréal, Québec, Canada
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