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Adhikari A, Bhutani VK, Mondal S, Das M, Darbar S, Ghosh R, Polley N, Das AK, Bhattacharya SS, Pal D, Mallick AK, Pal SK. Chemoprevention of bilirubin encephalopathy with a nanoceutical agent. Pediatr Res 2023; 93:827-837. [PMID: 35794251 DOI: 10.1038/s41390-022-02179-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 06/08/2022] [Accepted: 06/19/2022] [Indexed: 11/09/2022]
Abstract
BACKGROUND Targeted rapid degradation of bilirubin has the potential to thwart incipient bilirubin encephalopathy. We investigated a novel spinel-structured citrate-functionalized trimanganese tetroxide nanoparticle (C-Mn3O4 NP, the nanodrug) to degrade both systemic and neural bilirubin loads. METHOD Severe neonatal unconjugated hyperbilirubinemia (SNH) was induced in neonatal C57BL/6j mice model with phenylhydrazine (PHz) intoxication. Efficiency of the nanodrug on both in vivo bilirubin degradation and amelioration of bilirubin encephalopathy and associated neurobehavioral sequelae were evaluated. RESULTS Single oral dose (0.25 mg kg-1 bodyweight) of the nanodrug reduced both total serum bilirubin (TSB) and unconjugated bilirubin (UCB) in SNH rodents. Significant (p < 0.0001) UCB and TSB-degradation rates were reported within 4-8 h at 1.84 ± 0.26 and 2.19 ± 0.31 mg dL-1 h-1, respectively. Neural bilirubin load was decreased by 5.6 nmol g-1 (p = 0.0002) along with improved measures of neurobehavior, neuromotor movements, learning, and memory. Histopathological studies confirm that the nanodrug prevented neural cell reduction in Purkinje and substantia nigra regions, eosinophilic neurons, spongiosis, and cell shrinkage in SNH brain parenchyma. Brain oxidative status was maintained in nanodrug-treated SNH cohort. Pharmacokinetic data corroborated the bilirubin degradation rate with plasma nanodrug concentrations. CONCLUSION This study demonstrates the in vivo capacity of this novel nanodrug to reduce systemic and neural bilirubin load and reverse bilirubin-induced neurotoxicity. Further compilation of a drug-safety-dossier is warranted to translate this novel therapeutic chemopreventive approach to clinical settings. IMPACT None of the current pharmacotherapeutics treat severe neonatal hyperbilirubinemia (SNH) to prevent risks of neurotoxicity. In this preclinical study, a newly investigated nano-formulation, citrate-functionalized Mn3O4 nanoparticles (C-Mn3O4 NPs), exhibits bilirubin reduction properties in rodents. Chemopreventive properties of this nano-formulation demonstrate an efficacious, efficient agent that appears to be safe in these early studies. Translation of C-Mn3O4 NPs to prospective preclinical and clinical trials in appropriate in vivo models should be explored as a potential novel pharmacotherapy for SNH.
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Affiliation(s)
- Aniruddha Adhikari
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector 3, Salt Lake, Kolkata, 700106, India
| | - Vinod K Bhutani
- Department of Neonatal and Developmental Medicine, Lucile Packard Children's Hospital, Stanford University, 750 Welch Road, Palo Alto, CA, 94304, USA
| | - Susmita Mondal
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector 3, Salt Lake, Kolkata, 700106, India
| | - Monojit Das
- Department of Zoology, Uluberia College, University of Calcutta, Uluberia, Howrah, 711315, India
- Department of Zoology, Vidyasagar University, Rangamati, Midnapore, 721102, India
| | - Soumendra Darbar
- Research and Development Division, Dey's Medical Stores (Mfg.) Pvt. Ltd., 62 Bondel Road, Ballygunge, Kolkata, 700019, India
| | - Ria Ghosh
- Technical Research Centre, S. N. Bose National Centre for Basic Sciences, Block JD, Sector 3, Salt Lake, Kolkata, 700106, India
| | - Nabarun Polley
- Physical Chemistry - innoFSPEC, University of Potsdam, Am Mühlenberg 3, Golm, 14476, Potsdam, Germany
| | - Anjan Kumar Das
- Department of Pathology, Coochbehar Govt. Medical College and Hospital, Silver Jubilee Road, Coochbehar, 736101, India
| | | | - Debasish Pal
- Department of Zoology, Uluberia College, University of Calcutta, Uluberia, Howrah, 711315, India
| | - Asim Kumar Mallick
- Department of Pediatric Medicine, Nil Ratan Sirkar Medical College and Hospital, 138 AJC Bose Road, Sealdah, Rajabazar, Kolkata, 700014, India
| | - Samir Kumar Pal
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector 3, Salt Lake, Kolkata, 700106, India.
- Department of Zoology, Uluberia College, University of Calcutta, Uluberia, Howrah, 711315, India.
- Technical Research Centre, S. N. Bose National Centre for Basic Sciences, Block JD, Sector 3, Salt Lake, Kolkata, 700106, India.
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Mancuso C. The brain heme oxygenase/biliverdin reductase system as a target in drug research and development. Expert Opin Ther Targets 2022; 26:361-374. [PMID: 35285395 DOI: 10.1080/14728222.2022.2052848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION The heme oxygenase/biliverdin reductase (HO/BVR) system is involved in heme metabolism. The inducible isoform of HO (HO-1) and BVR both exert cytoprotective effects by enhancing cell stress response. In this context, some xenobiotics, which target HO-1, including herbal products, behave as neuroprotectants in several experimental models of neurodegeneration. Despite this, no drug having either HO-1 or BVR as a main target is currently available. AREAS COVERED After a description of the brain HO/BVR system, the paper analyzes the main classes of drugs acting on the nervous system, with HO as second-level target, and their neuroprotective potential. Finally, the difficulties that exist for the development of drugs acting on HO/BVR and the possible ways to overcome these hurdles are examined. EXPERT OPINION Although the limited clinical evidence has restricted the translational research on the HO/BVR system, mainly because of the dual nature of its by-products, there has been growing interest in the therapeutic potential of these enzymes. Scientists should boost the translational research on the HO/BVR system which could be supported by the significant evidence provided by preclinical studies.
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Affiliation(s)
- Cesare Mancuso
- Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy.,Department of Healthcare Surveillance and Bioethics, Section of Pharmacology, Università Cattolica del Sacro Cuore, Rome, Italy
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Wiedmeier SE, Bahr TM, Ohls RK, Christensen TR, Baer VL, Ilstrup SJ, Cail K, Christensen RD. Exchange transfusion for hemolytic hyperbilirubinemia: could some be averted by emergent administration of an inhibitor of bilirubin production? J Perinatol 2021; 41:860-864. [PMID: 32669646 DOI: 10.1038/s41372-020-0736-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/01/2020] [Accepted: 07/07/2020] [Indexed: 11/09/2022]
Abstract
OBJECTIVES The objective of this study is to explore the hypothetical number of neonates where an exchange transfusion (ET) could be prevented by emergency administration of an inhibitor of bilirubin production. STUDY DESIGN We identified all neonates who received an ET in our NICUs during the past 12 years. We reviewed the indications for ET and recorded the time between ordering and beginning the exchange. RESULTS Forty-six neonates underwent ET, 37 (80.4%) for hemolytic hyperbilirubinemia (36.9 ± 2.9 weeks gestation and 2.5 ± 2.1 days old at ET). The mean delay period was 7.5 ± 3.5 h. Nine (19.6%) had ET not involving bilirubin. CONCLUSIONS A trial testing compounds that can inhibit bilirubin production would have about three eligible neonates/years in our system. Since our births are 1% of national, up to 300 neonates/years might qualify for such a study.
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Affiliation(s)
- Susan E Wiedmeier
- Division of Neonatology, Department of Pediatrics, University of Utah Health, Salt Lake City, UT, USA
| | - Timothy M Bahr
- Division of Neonatology, Department of Pediatrics, University of Utah Health, Salt Lake City, UT, USA.
| | - Robin K Ohls
- Division of Neonatology, Department of Pediatrics, University of Utah Health, Salt Lake City, UT, USA
| | | | - Vickie L Baer
- Women and Newborns Research, Intermountain Healthcare, Salt Lake City, UT, USA
| | - Sarah J Ilstrup
- Department of Pathology, Intermountain Medical Center, Murray, UT, USA
| | - Kelly Cail
- ARUP Laboratories, Salt Lake City, UT, USA
| | - Robert D Christensen
- Division of Neonatology, Department of Pediatrics, University of Utah Health, Salt Lake City, UT, USA.,Women and Newborns Research, Intermountain Healthcare, Salt Lake City, UT, USA.,Division Hematology/Oncology, Department of Pediatrics, University of Utah Health, Salt Lake City, UT, USA
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Antibacterial Activity of Synthetic Cationic Iron Porphyrins. Antioxidants (Basel) 2020; 9:antiox9100972. [PMID: 33050461 PMCID: PMC7601463 DOI: 10.3390/antiox9100972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 09/15/2020] [Accepted: 09/17/2020] [Indexed: 12/28/2022] Open
Abstract
Widespread antibiotic resistance demands new strategies for fighting infections. Porphyrin-based compounds were long ago introduced as photosensitizers for photodynamic therapy, but light-independent antimicrobial activity of such compounds has not been systematically explored. The results of this study demonstrate that synthetic cationic amphiphilic iron N-alkylpyridylporphyrins exert strong bactericidal action at concentrations as low as 5 μM. Iron porphyrin, FeTnHex-2-PyP, which is well tolerated by laboratory animals, efficiently killed Gram-negative and Gram-positive microorganisms. Its bactericidal activity was oxygen-independent and was controlled by the lipophilicity and accumulation of the compound in bacterial cells. Such behavior is in contrast with the anionic gallium protoporphyrin IX, whose efficacy depends on cellular heme uptake systems. Under aerobic conditions, however, the activity of FeTnHex-2-PyP was limited by its destruction due to redox-cycling. Neither iron released from the Fe-porphyrin nor other decomposition products were the cause of the bactericidal activity. FeTnHex-2-PyP was as efficient against antibiotic-sensitive E. coli and S. aureus as against their antibiotic-resistant counterparts. Our data demonstrate that development of amphiphilic, positively charged metalloporphyrins might be a promising approach in the introduction of new weapons against antibiotic-resistant strains.
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Two Faces of Heme Catabolic Pathway in Newborns: A Potential Role of Bilirubin and Carbon Monoxide in Neonatal Inflammatory Diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:7140496. [PMID: 32908636 PMCID: PMC7450323 DOI: 10.1155/2020/7140496] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 07/27/2020] [Indexed: 12/18/2022]
Abstract
In an infant's body, all the systems undergo significant changes in order to adapt to the new, extrauterine environment and challenges which it poses. Fragile homeostasis can be easily disrupted as the defensive mechanisms are yet imperfect. The activity of antioxidant enzymes, i.e., superoxide dismutase, catalase, and glutathione peroxidase, is low; therefore, neonates are especially vulnerable to oxidative stress. Free radical burden significantly contributes to neonatal illnesses such as sepsis, retinopathy of premature, necrotizing enterocolitis, bronchopulmonary dysplasia, or leukomalacia. However, newborns have an important ally-an inducible heme oxygenase-1 (HO-1) which expression rises rapidly in response to stress stimuli. HO-1 activity leads to production of carbon monoxide (CO), free iron ion, and biliverdin; the latter is promptly reduced to bilirubin. Although CO and bilirubin used to be considered noxious by-products, new interesting properties of those compounds are being revealed. Bilirubin proved to be an efficient free radicals scavenger and modulator of immune responses. CO affects a vast range of processes such as vasodilatation, platelet aggregation, and inflammatory reactions. Recently, developed nanoparticles consisting of PEGylated bilirubin as well as several kinds of molecules releasing CO have been successfully tested on animal models of inflammatory diseases. This paper focuses on the role of heme metabolites and their potential utility in prevention and treatment of neonatal diseases.
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Pibiri M, Leoni VP, Atzori L. Heme oxygenase-1 inhibitor tin-protoporphyrin improves liver regeneration after partial hepatectomy. Life Sci 2018; 204:9-14. [PMID: 29738777 DOI: 10.1016/j.lfs.2018.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 04/24/2018] [Accepted: 05/04/2018] [Indexed: 12/22/2022]
Abstract
AIMS This study investigates the effects of the heme oxygenase-1 (HO-1) inhibitor tin protoporphyrin IX (SnPP), on rat liver regeneration following 2/3 partial hepatectomy (PH) in order to clarify the controversial role of HO-1 in the regulation of cellular growth. MAIN METHODS Male Wistar rats received a subcutaneous injection of either SnPP (10 μmoles/kg body weight) or saline 12 h before PH and 0, 12 and 24 h after surgery. Rats were killed from 0.5 to 36 h after PH. Bromodeoxyuridine (BrdU) incorporation was used to analyze cell proliferation. Immunohistochemistry, Western blot analysis and quantitative Real Time-PCR were used to assess molecular and cellular changes after PH. KEY FINDINGS Data obtained have shown that administration of SnPP caused an increased entry of hepatocytes into S phase after PH, as demonstrated by labeling (L.I.) and mitotic (M.I.) indexes. Furthermore, enhanced cell cycle entry in PH-animals pre-treated with SnPP was associated with an earlier activation of IL-6 and transcription factors involved in liver regeneration, such as phospho-JNK and phospho-STAT3. SIGNIFICANCE Summarizing, data here reported demonstrate that inhibition of HO-1 enhances rat liver regeneration after PH which is associated to a very rapid increase in the levels of inflammatory mediators such as IL-6, phopsho-JNK and phospho-STAT3, suggesting that HO-1 could act as a negative modulator of liver regeneration. Knowledge about the mechanisms of liver regeneration can be applied to clinical problems caused by delayed liver growth, and HO-1 repression may be a mechanism by which cells can faster proliferate in response to tissue damage.
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Affiliation(s)
- Monica Pibiri
- Department of Biomedical Sciences, Oncology and Molecular Pathology Unit, University of Cagliari, Via Porcell 4, 09124 Cagliari, Italy
| | - Vera Piera Leoni
- Department of Biomedical Sciences, Oncology and Molecular Pathology Unit, University of Cagliari, Via Porcell 4, 09124 Cagliari, Italy
| | - Luigi Atzori
- Department of Biomedical Sciences, Oncology and Molecular Pathology Unit, University of Cagliari, Via Porcell 4, 09124 Cagliari, Italy.
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Salerno L, Romeo G, Modica MN, Amata E, Sorrenti V, Barbagallo I, Pittalà V. Heme oxygenase-1: A new druggable target in the management of chronic and acute myeloid leukemia. Eur J Med Chem 2017; 142:163-178. [DOI: 10.1016/j.ejmech.2017.07.031] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/14/2017] [Accepted: 07/17/2017] [Indexed: 12/11/2022]
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Mancuso C. Bilirubin and brain: A pharmacological approach. Neuropharmacology 2017; 118:113-123. [PMID: 28315352 DOI: 10.1016/j.neuropharm.2017.03.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/09/2017] [Accepted: 03/12/2017] [Indexed: 01/01/2023]
Abstract
For many decades, the world scientific literature has accounted for a number of works on the biological effects of bilirubin-IXalpha (BR). The first studies focused on the neurotoxic effects of the excessive production of BR, in particular regarding both physiological neonatal jaundice and the more severe ones, typically as consequences of severe hemolysis or other underlying diseases. Only since 1987, has significant evidence, however, underlined the neuroprotective role of BR linked to the scavenging effect of free radicals as reactive oxygen species and nitric oxide and its congeners. Despite the presence in the literature of many excellent papers dealing with the multiple roles played by BR in health and disease, there were very few and somewhat dated reviews that summarize the key findings related to the neuroprotective and neurotoxic effects of the bile pigment and underlying mechanisms. In light of the previous statements, the aim of this review is to provide a summary of the main discoveries in the last years on the effects of BR on the central nervous system. An analytical description about the synthesis of BR, its distribution in the systemic circulation, liver metabolism and elimination through feces and urine will be provided, together with the main mechanisms claimed to describe the neurotoxicity and neuroprotection by the bile pigment. Finally, the possible translational aspects of pharmacological modulation in the production of BR in order to prevent or counteract toxic effects or enhance the protective actions, will be discussed.
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Affiliation(s)
- Cesare Mancuso
- Institute of Pharmacology, Catholic University School of Medicine, Largo F. Vito, 1-00168 Rome, Italy.
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A Novel High-Content Immunofluorescence Assay as a Tool to Identify at the Single Cell Level γ-Globin Inducing Compounds. PLoS One 2015; 10:e0141083. [PMID: 26509275 PMCID: PMC4624791 DOI: 10.1371/journal.pone.0141083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 10/05/2015] [Indexed: 12/15/2022] Open
Abstract
The identification of drugs capable of reactivating γ-globin to ameliorate β-thalassemia and Sickle Cell anemia is still a challenge, as available γ-globin inducers still have limited clinical indications. High-throughput screenings (HTS) aimed to identify new potentially therapeutic drugs require suitable first-step-screening methods combining the possibility to detect variation in the γ/β globin ratio with the robustness of a cell line. We took advantage of a K562 cell line variant expressing β-globin (β-K562) to set up a new multiplexed high-content immunofluorescence assay for the quantification of γ- and β-globin content at single-cell level. The assay was validated by using the known globin inducers hemin, hydroxyurea and butyric acid and further tested in a pilot screening that confirmed HDACs as targets for γ-globin induction (as proved by siRNA-mediated HDAC3 knockdown and by treatment with HDACs inhibitors entinostat and dacinostat) and identified Heme-oxygenases as novel candidate targets for γ-globin induction. Indeed, Heme-oxygenase2 siRNA knockdown as well as its inhibition by Tin protoporphyrin-IX (TinPPIX) greatly increased γ-globin expression. This result is particularly interesting as several metalloporphyrins have already been developed for clinical uses and could be tested (alone or in combination with other drugs) to improve pharmacological γ-globin reactivation for the treatment of β-hemoglobinopathies.
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Strategies for neonatal hyperbilirubinemia: a literature review. MCN Am J Matern Child Nurs 2015; 38:377-82;quiz 383-4. [PMID: 24145492 DOI: 10.1097/nmc.0b013e3182a1fb7a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
"Common" neonatal jaundice can lead to dangerous levels of hyperbilirubinemia, causing neurological damage and even death. This article outlines evidence-based assessment techniques, management guidelines, and treatments for neonatal hyperbilirubinemia, addressing complexities that have arisen with new technologies and research results. We also explicate the role of the nurse in both prevention and care of patients and families who are affected by hyperbilirubinemia and jaundice.
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Rodeck B, Zimmer KP. Stoffwechselerkrankungen. PÄDIATRISCHE GASTROENTEROLOGIE, HEPATOLOGIE UND ERNÄHRUNG 2013. [PMCID: PMC7498805 DOI: 10.1007/978-3-642-24710-1_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Entsprechend ihrer Wanderung bei isoelektrischer Fokussierung werden die allelen Varianten des α1-AT als Proteinaseinhibitorphänotypen (Pi) klassifiziert. Die dominierende Isoform ist der normale Phänotyp M, daneben gibt es die Mangelvarianten S und Z sowie eine 0-Variante.
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Affiliation(s)
- Burkhard Rodeck
- Zentrum für Kinder- und Jugendmedizin, Christliches Kinderhospital Osnabrück, Johannisfreiheit 1, 49074 Osnabrück, Deutschland
| | - Klaus-Peter Zimmer
- grid.411067.50000000085849230Abteilung Allgemeine Pädiatrie und Neonatalogie, Universitätsklinikum Gießen und Marburg GmbH, Zentrum für Kinderheilkunde und Jugendmedizin, Feulgenstr. 12, 35392 Gießen, Deutschland
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Abstract
It is estimated that about two thirds of newborns will appear clinically jaundiced during their first weeks of life. As newborns and their mothers spend fewer days in the hospital after birth, the number of infants readmitted yearly in the United States for neonatal jaundice over the last 10 years has increased by 160%. A portion of these infants present to the emergency department, requiring a careful history and physical examination assessing them for the risk factors associated with pathologic bilirubin levels. Although the spectrum of illness may be great, the overwhelming etiology of neonatal jaundice presenting to an emergency department is physiologic and not due to infection or isoimmunization. Therefore, a little more than a good history, physical examination, and indirect/direct bilirubin levels are needed to evaluate an otherwise well-appearing jaundiced newborn. The American Academy of Pediatrics' 2004 clinical practice guidelines for "Management of Hyperbilirubinemia in the Newborn Infant 35 or More Weeks of Gestation" are a helpful and easily accessible resource when evaluating jaundiced newborns (available at http://aappolicy.aappublications.org/cgi/content/full/pediatrics;114/1/297). There are several exciting developments on the horizon for the diagnosis and management of hyperbilirubinemia including increasing use of transcutaneous bilirubin measuring devices and medications such as tin mesoporphyrin and intravenous immunoglobulin that may decrease the need for exchange transfusions.
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Stark MJ, Clifton VL, Wright IMR. Carbon monoxide is a significant mediator of cardiovascular status following preterm birth. Pediatrics 2009; 124:277-84. [PMID: 19564310 DOI: 10.1542/peds.2008-0877] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE With male gender as a strong predictor of cardiovascular instability, we hypothesized that gender-specific differences in circulating carbon monoxide levels contributed to dysregulated microvascular function in preterm male infants. METHODS Infants born at 24 to 34 weeks of gestation (N = 84) were studied in a regional tertiary neonatal unit. Carboxyhemoglobin levels were measured through spectrophotometry in umbilical arterial blood and at 24, 72, and 120 hours after birth. Microvascular blood flow was determined through laser Doppler flowmetry. RESULTS Carboxyhemoglobin levels demonstrated a strong inverse relationship with gestational age (r = -0.636; P < .001) and were higher in boys (P = .032). Repeated-measures analysis of variance showed a significant decrease in arterial carboxyhemoglobin levels over time (P < .001), with significant between-subjects effects for gestational age (P = .011) and gender (P = .025). Positive correlations with microvascular blood flow at 24 hours of age (r = 0.495; P < .001) and 120 hours of age (r = 0.548; P < .001) were observed. With controlling for gestational age, carboxyhemoglobin levels at 72 hours were greater for infants who died in the first week of life (P = .035). CONCLUSIONS The gestational age- and gender-specific differences in carboxyhemoglobin levels and the relationship with dysregulated microvascular blood flow, a state related to greater illness severity and hypotension, are novel findings not confined solely to sick preterm infants. Both inducible heme oxygenase-dependent and non-heme oxygenase-dependent pathways may initially play a central role in carbon monoxide production, inducing pathophysiologic processes in a gender-specific manner.
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Affiliation(s)
- Michael J Stark
- Mother and Babies Research Centre, Hunter Medical Research Institute, University of Newcastle, Newcastle, Australia
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Kinobe RT, Dercho RA, Nakatsu K. Inhibitors of the heme oxygenase - carbon monoxide system: on the doorstep of the clinic? Can J Physiol Pharmacol 2008; 86:577-99. [PMID: 18758507 DOI: 10.1139/y08-066] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The past decade has seen substantial developments in our understanding of the physiology, pathology, and pharmacology of heme oxygenases (HO), to the point that investigators in the field are beginning to contemplate therapies based on administration of HO agonists or HO inhibitors. A significant amount of our current knowledge is based on the judicious application of metalloporphyrin inhibitors of HO, despite their limitations of selectivity. Recently, imidazole-based compounds have been identified as potent and more selective HO inhibitors. This 'next generation' of HO inhibitors offers a number of desirable characteristics, including isozyme selectivity, negligible effects on HO protein expression, and physicochemical properties favourable for in vivo distribution. Some of the applications of HO inhibitors that have been suggested are treatment of hyperbilirubinemia, neurodegenerative disorders, certain types of cancer, and bacterial and fungal infections. In this review, we address various approaches to altering HO activity with a focus on the potential applications of second-generation inhibitors of HO.
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Affiliation(s)
- Robert T Kinobe
- Department of Pharmacology and Toxicology, Queen's University, Kingston, ON Canada
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Abstract
The changing management of haemolytic disease of the newborn is reviewed
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Affiliation(s)
- Neil A Murray
- Imperial College, Department of Paediatrics, 5th Floor, Ham House, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
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