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Tamir-Hostovsky L, Ivanovska J, Parajón E, Patel R, Wang H, Biouss G, Ivanovski N, Belik J, Pierro A, Montandon G, Gauda EB. Maturational effect of leptin on CO 2 chemosensitivity in newborn rats. Pediatr Res 2023; 94:971-978. [PMID: 37185965 DOI: 10.1038/s41390-023-02604-3] [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: 07/18/2022] [Revised: 03/28/2023] [Accepted: 04/01/2023] [Indexed: 05/17/2023]
Abstract
BACKGROUND Leptin augments central CO2 chemosensitivity and stabilizes breathing in adults. Premature infants have unstable breathing and low leptin levels. Leptin receptors are on CO2 sensitive neurons in the Nucleus Tractus Solitarius (NTS) and locus coeruleus (LC). We hypothesized that exogenous leptin improves hypercapnic respiratory response in newborn rats by improving central CO2 chemosensitivity. METHODS In rats at postnatal day (p)4 and p21, hyperoxic and hypercapnic ventilatory responses, and pSTAT and SOCS3 protein expression in the hypothalamus, NTS and LC were measured before and after treatment with exogenous leptin (6 µg/g). RESULTS Exogenous leptin increased the hypercapnic response in p21 but not in p4 rats (P ≤ 0.001). At p4, leptin increased pSTAT expression only in the LC, and SOCS3 expression in the NTS and LC; while at p21 pSTAT and SOCS3 levels were higher in the hypothalamus, NTS, and LC (P ≤ 0.05). CONCLUSIONS We describe the developmental profile of the effect of exogenous leptin on CO2 chemosensitivity. Exogenous leptin does not augment central CO2 sensitivity during the first week of life in newborn rats. The translational implication of these findings is that low plasma leptin levels in premature infants may not be contributing to respiratory instability. IMPACT Exogenous leptin does not augment CO2 sensitivity during the first week of life in newborn rats, similar to the developmental period when feeding behavior is resistant to leptin. Exogenous leptin increases CO2 chemosensitivity in newborn rats after the 3rd week of life and upregulates the expression of pSTAT and SOC3 in the hypothalamus, NTS and LC. Low plasma leptin levels in premature infants are unlikely contributors to respiratory instability via decreased CO2 sensitivity in premature infants. Thus, it is highly unlikely that exogenous leptin would alter this response.
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Affiliation(s)
- Liran Tamir-Hostovsky
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Julijana Ivanovska
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Eleana Parajón
- Cellular and Molecular Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Rachana Patel
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Huanhuan Wang
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - George Biouss
- Division of General and Thoracic Surgery, Developmental and Stem Cell Biology Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Nikola Ivanovski
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Jaques Belik
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Agostino Pierro
- Division of General and Thoracic Surgery, Developmental and Stem Cell Biology Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Gaspard Montandon
- Keenan Research Centre for Biomedical Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, ON, Canada
| | - Estelle B Gauda
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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Mohammadi A, Higazy R, Gauda EB. PGC-1α activity and mitochondrial dysfunction in preterm infants. Front Physiol 2022; 13:997619. [PMID: 36225305 PMCID: PMC9548560 DOI: 10.3389/fphys.2022.997619] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 09/09/2022] [Indexed: 11/26/2022] Open
Abstract
Extremely low gestational age neonates (ELGANs) are born in a relatively hyperoxic environment with weak antioxidant defenses, placing them at high risk for mitochondrial dysfunction affecting multiple organ systems including the nervous, respiratory, ocular, and gastrointestinal systems. The brain and lungs are highly affected by mitochondrial dysfunction and dysregulation in the neonate, causing white matter injury (WMI) and bronchopulmonary dysplasia (BPD), respectively. Adequate mitochondrial function is important in providing sufficient energy for organ development as it relates to alveolarization and axonal myelination and decreasing oxidative stress via reactive oxygen species (ROS) and reactive nitrogen species (RNS) detoxification. Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) is a master regulator of mitochondrial biogenesis and function. Since mitochondrial dysfunction is at the root of WMI and BPD pathobiology, exploring therapies that can regulate PGC-1α activity may be beneficial. This review article describes several promising therapeutic agents that can mitigate mitochondrial dysfunction through direct and indirect activation and upregulation of the PGC-1α pathway. Metformin, resveratrol, omega 3 fatty acids, montelukast, L-citrulline, and adiponectin are promising candidates that require further pre-clinical and clinical studies to understand their efficacy in decreasing the burden of disease from WMI and BPD in preterm infants.
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Affiliation(s)
- Atefeh Mohammadi
- The Hospital for Sick Children, Division of Neonatology, Department of Pediatrics and Translational Medicine Program, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Randa Higazy
- The Hospital for Sick Children, Division of Neonatology, Department of Pediatrics and Translational Medicine Program, Toronto, ON, Canada
| | - Estelle B. Gauda
- The Hospital for Sick Children, Division of Neonatology, Department of Pediatrics and Translational Medicine Program, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- *Correspondence: Estelle B. Gauda,
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Ivanovska J, Kang NYC, Ivanovski N, Nagy A, Belik J, Gauda EB. Recombinant adiponectin protects the newborn rat lung from lipopolysaccharide-induced inflammatory injury. Physiol Rep 2020; 8:e14553. [PMID: 32889775 PMCID: PMC7507528 DOI: 10.14814/phy2.14553] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/24/2020] [Accepted: 07/25/2020] [Indexed: 02/06/2023] Open
Abstract
Preterm infants are at high risk for developing bronchopulmonary dysplasia and pulmonary hypertension from inflammatory lung injury. In adult models, adiponectin (APN)—an adipocyte‐derived hormone—protects the lung from inflammatory injury and pulmonary vascular remodeling. Cord blood APN levels in premature infants born < 26 weeks gestation are 5% of the level in infants born at term. We previously reported the expression profile of APN and its receptors in neonatal rat lung homogenates during the first 3 weeks of postnatal development. Here, we characterize the expression profile of APN and its receptors in specific lung cells and the effects of exogenous recombinant APN (rAPN) on lipopolysaccharide‐(LPS)‐induced cytokine and chemokine production in total lung homogenates and specific lung cells. In vitro, rAPN added to primary cultures of pulmonary artery smooth muscle cells attenuated the expression of LPS‐induced pro‐inflammatory cytokines while increasing the expression of anti‐inflammatory cytokines. In vivo, intraperitoneal rAPN (2 mg/kg), given 4 hr prior to intrapharyngeal administration of LPS (5 mg/kg) to newborn rats at postnatal day 4, significantly reduced gene and protein expression of the pro‐inflammatory cytokine IL‐1ß and reduced protein expression of the chemokines monocyte chemoattractant protein (MCP‐1) and macrophage inflammatory protein‐1 alpha (MIP‐1α) in the lung. LPS‐induced histopathological changes in the lung were also decreased. Moreover, rAPN given 20 hr after intrapharyngeal LPS had a similar effect on lung inflammation. These findings suggest a role for APN in protecting the lung from inflammation during early stages of lung development.
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Affiliation(s)
- Julijana Ivanovska
- The Hospital for Sick Children, Division of Neonatology, Department of Pediatrics and Translational Medicine Program, University of Toronto, Toronto, ON, Canada
| | - Na-Young Cindy Kang
- The Hospital for Sick Children, Division of Neonatology, Department of Pediatrics and Translational Medicine Program, University of Toronto, Toronto, ON, Canada
| | - Nikola Ivanovski
- The Hospital for Sick Children, Division of Neonatology, Department of Pediatrics and Translational Medicine Program, University of Toronto, Toronto, ON, Canada
| | - Avita Nagy
- Department of Pediatric Laboratory Medicine, University of Toronto, Toronto, ON, Canada
| | - Jaques Belik
- The Hospital for Sick Children, Division of Neonatology, Department of Pediatrics and Translational Medicine Program, University of Toronto, Toronto, ON, Canada
| | - Estelle B Gauda
- The Hospital for Sick Children, Division of Neonatology, Department of Pediatrics and Translational Medicine Program, University of Toronto, Toronto, ON, Canada
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