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Paping A, Ehrlich L, Melchior K, Ziska T, Wippermann W, Starke A, Heinichen K, Henrich W, Braun T. A Sustainable Translational Sheep Model for Planned Cesarean Delivery of Contraction-Free Ewes. Reprod Sci 2024; 31:791-802. [PMID: 37848643 PMCID: PMC10912125 DOI: 10.1007/s43032-023-01365-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 09/14/2023] [Indexed: 10/19/2023]
Abstract
We evaluated whether the sheep constitutes a useful translational model to evaluate anatomical and surgical aspects of cesarean delivery (CD) from a human medical perspective with the aim of both maternal and neonatal well-being. Our hypothesis was that CD in contraction-free ewes is not associated with major complications. Primary endpoint was the transferability of anatomical conditions and surgical techniques of CD from the ewe to the human. Secondary endpoints were maternal and fetal survival, occurrence of retained fetal membranes, metritis, mastitis, or wound infections. Forty-eight Merino ewes were delivered by CD after 95% gestation (142-144 days). Both ewes and newborn lambs were cared for intensively after the delivery. Ovine uterine anatomy during CD appeared slightly different but comparable to the human uterus. Uterine incisions were mostly performed in the uterine horns, not in the uterine corpus. The ovine uterine wall is thinner than in humans. All ewes survived without any major complications. Seventy-seven (88.5%) out of 87 live-born lambs survived without any complications. The contraction-free ewe constitutes an appropriate and safe model to evaluate anatomical and surgical aspects of CD from a human medical perspective. We present a step-by-step manual for successfully planned cesarean delivery for sheep including the perioperative management illustrated with photographs and a five-minute video. With adequate planning and a reasonable number of staff, it is possible to safeguard both maternal and neonatal survival. This sustainable translational medicine model offers additional potential for the offspring to be used for further research studies (e.g., transgenerational inheritance research).
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Affiliation(s)
- Alexander Paping
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Obstetrics, Augustenburger Platz 1, 13353, Berlin, Germany.
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Division of 'Experimental Obstetrics', Berlin, Germany.
| | - Loreen Ehrlich
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Division of 'Experimental Obstetrics', Berlin, Germany
| | - Kerstin Melchior
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Division of 'Experimental Obstetrics', Berlin, Germany
| | - Thomas Ziska
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Division of 'Experimental Obstetrics', Berlin, Germany
| | - Wolf Wippermann
- Clinic for Ruminants and Swine, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Alexander Starke
- Clinic for Ruminants and Swine, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Karin Heinichen
- Oberholz Farm for Teaching and Research, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany
| | - Wolfgang Henrich
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Obstetrics, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Thorsten Braun
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Obstetrics, Augustenburger Platz 1, 13353, Berlin, Germany
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Division of 'Experimental Obstetrics', Berlin, Germany
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Sutherland MR, Malik W, Nguyen VB, Tran V, Polglase GR, Black MJ. Renal morphology and glomerular capillarisation in young adult sheep born moderately preterm. J Dev Orig Health Dis 2021; 12:975-981. [PMID: 33300490 DOI: 10.1017/s2040174420001208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Preterm birth (delivery <37 weeks of gestation) is associated with impaired glomerular capillary growth in neonates; if this persists, it may be a contributing factor in the increased risk of hypertension and chronic kidney disease in people born preterm. Therefore, in this study, we aimed to determine the long-term impact of preterm birth on renal morphology, in adult sheep. Singleton male sheep were delivered moderately preterm at 132 days (~0.9) of gestation (n = 6) or at term (147 days gestation; n = 6) and euthanised at 14.5 months of age (early adulthood). Stereological methods were used to determine mean renal corpuscle and glomerular volumes, and glomerular capillary length and surface area, in the outer, mid and inner regions of the renal cortex. Glomerulosclerosis and interstitial collagen levels were assessed histologically. By 14.5 months of age, there was no difference between the term and preterm sheep in body or kidney weight. Renal corpuscle volume was significantly larger in the preterm sheep than the term sheep, with the preterm sheep exhibiting enlarged Bowman's spaces; however, there was no difference in glomerular volume between groups, with no impact of preterm birth on capillary length or surface area per glomerulus. There was also no difference in interstitial collagen levels or glomerulosclerosis index between groups. Findings suggest that moderate preterm birth does not adversely affect glomerular structure in early adulthood. The enlarged Bowman's space in the renal corpuscles of the preterm sheep kidneys, however, is of concern and merits further research into its cause and functional consequences.
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Affiliation(s)
- Megan R Sutherland
- Department of Anatomy and Developmental Biology and the Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Waleed Malik
- Department of Anatomy and Developmental Biology and the Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Vivian B Nguyen
- Department of Anatomy and Developmental Biology and the Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Vivian Tran
- Department of Anatomy and Developmental Biology and the Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Department of Obstetrics and Gynaecology, Monash University and the Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Mary Jane Black
- Department of Anatomy and Developmental Biology and the Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
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Lombardo P, Nguyen VB, Flores TJ, Sutherland MR, Nitsos I, Allison BJ, Parkington H, Tare M, Harding R, De Matteo R, Schneider M, Polglase GR, Black MJ. Early impact of moderate preterm birth on the structure, function and gene expression of conduit arteries. Exp Physiol 2020; 105:1256-1267. [PMID: 32436635 DOI: 10.1113/ep088117] [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: 08/22/2019] [Accepted: 05/19/2020] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? What is the immediate impact of moderate preterm birth on the structure and function of major conduit arteries using a pre-clinical sheep model? What is the main finding and its importance? Postnatal changes in conduit arteries, including a significant decrease in collagen within the thoracic aortic wall (predominately males), narrowed carotid arteries, reduced aortic systolic blood flow, and upregulation of the mRNA expression of cell adhesion and inflammatory markers at 2 days of age in preterm lambs compared to controls, may increase the risk of cardiovascular impairment in later life. ABSTRACT The aim of this work was to compare the structure and function of the conduit arteries of moderately preterm and term-born lambs and to determine whether vascular injury-associated genes were upregulated. Time-mated ewes were induced to deliver either preterm (132 ± 1 days of gestation; n = 11 females and n = 10 males) or at term (147 ± 1 days of gestation; n = 10 females and n = 5 males). Two days after birth, ultrasound imaging of the proximal ascending aorta, main, right and left pulmonary arteries, and right and left common carotid arteries was conducted in anaesthetized lambs. Lambs were then killed and segments of the thoracic aorta and left common carotid artery were either snap frozen for real-time PCR analyses or immersion-fixed for histological quantification of collagen, smooth muscle and elastin within the medial layer. Overall there were few differences in vascular structure between moderately preterm and term lambs. However, there was a significant decrease in the proportion of collagen within the thoracic aortic wall (predominantly in males), narrowing of the common carotid arteries and a reduction in peak aortic systolic blood flow in preterm lambs. In addition, there was increased mRNA expression of the cell adhesion marker P-selectin in the thoracic aortic wall and the pro-inflammatory marker IL-1β in the left common carotid artery in preterm lambs, suggestive of postnatal vascular injury. Early postnatal differences in the function and structure of conduit arteries and evidence of vascular injury in moderately preterm offspring may place them at greater risk of cardiovascular impairment later in life.
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Affiliation(s)
- Paul Lombardo
- Department of Medical Imaging and Radiation Sciences, Monash University, Victoria, Clayton, Australia
| | - Vivian B Nguyen
- Department of Anatomy and Developmental Biology and the Biomedicine Discovery Institute, Monash University, Victoria, Clayton, Australia
| | - Tracey J Flores
- Department of Anatomy and Developmental Biology and the Biomedicine Discovery Institute, Monash University, Victoria, Clayton, Australia
| | - Megan R Sutherland
- Department of Anatomy and Developmental Biology and the Biomedicine Discovery Institute, Monash University, Victoria, Clayton, Australia
| | - Ilias Nitsos
- The Ritchie Centre, Department of Obstetrics & Gynaecology, Monash University and Hudson Institute of Medical Research, Victoria, Clayton, Australia
| | - Beth J Allison
- The Ritchie Centre, Department of Obstetrics & Gynaecology, Monash University and Hudson Institute of Medical Research, Victoria, Clayton, Australia
| | - Helena Parkington
- Department of Physiology and the Biomedicine Discovery Institute, Monash University, Victoria, Clayton, Australia
| | - Marianne Tare
- Department of Physiology and the Biomedicine Discovery Institute, Monash University, Victoria, Clayton, Australia
| | - Richard Harding
- Department of Anatomy and Developmental Biology and the Biomedicine Discovery Institute, Monash University, Victoria, Clayton, Australia
| | - Robert De Matteo
- Department of Anatomy and Developmental Biology and the Biomedicine Discovery Institute, Monash University, Victoria, Clayton, Australia
| | - Michal Schneider
- Department of Medical Imaging and Radiation Sciences, Monash University, Victoria, Clayton, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Department of Obstetrics & Gynaecology, Monash University and Hudson Institute of Medical Research, Victoria, Clayton, Australia
| | - M Jane Black
- Department of Anatomy and Developmental Biology and the Biomedicine Discovery Institute, Monash University, Victoria, Clayton, Australia
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Hrabalkova L, Takahashi T, Kemp MW, Stock SJ. Antenatal Corticosteroids for Fetal Lung Maturity - Too Much of a Good Thing? Curr Pharm Des 2020; 25:593-600. [PMID: 30914016 DOI: 10.2174/1381612825666190326143814] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 03/22/2019] [Indexed: 12/22/2022]
Abstract
BACKGROUND Between 5-15% of babies are born prematurely worldwide, with preterm birth defined as delivery before 37 completed weeks of pregnancy (term is at 40 weeks of gestation). Women at risk of preterm birth receive antenatal corticosteroids as part of standard care to accelerate fetal lung maturation and thus improve neonatal outcomes in the event of delivery. As a consequence of this treatment, the entire fetal organ system is exposed to the administered corticosteroids. The implications of this exposure, particularly the long-term impacts on offspring health, are poorly understood. AIMS This review will consider the origins of antenatal corticosteroid treatment and variations in current clinical practices surrounding the treatment. The limitations in the evidence base supporting the use of antenatal corticosteroids and the evidence of potential harm to offspring are also summarised. RESULTS Little has been done to optimise the dose and formulation of antenatal corticosteroid treatment since the first clinical trial in 1972. International guidelines for the use of the treatment lack clarity regarding the recommended type of corticosteroid and the gestational window of treatment administration. Furthermore, clinical trials cited in the most recent Cochrane Review have limitations which should be taken into account when considering the use of antenatal corticosteroids in clinical practice. Lastly, there is limited evidence regarding the long-term effects on the different fetal organ systems exposed in utero, particularly when the timing of corticosteroid administration is sub-optimal. CONCLUSION Further investigations are urgently needed to determine the most safe and effective treatment regimen for antenatal corticosteroids, particularly regarding the type of corticosteroid and optimal gestational window of administration. A clear consensus on the use of this common treatment could maximise the benefits and minimise potential harms to offspring.
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Affiliation(s)
- Lenka Hrabalkova
- Tommy's Centre for Maternal and Fetal Health at the MRC Centre for Reproductive Health, University of Edinburgh, Edinburgh, United Kingdom
| | | | - Matthew W Kemp
- Tohoku University Hospital, Sendai, Miyagi, Japan.,Division of Obstetrics and Gynaecology, University of Western Australia, Perth, Australia
| | - Sarah J Stock
- Tommy's Centre for Maternal and Fetal Health at the MRC Centre for Reproductive Health, University of Edinburgh, Edinburgh, United Kingdom.,Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, United Kingdom
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5
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Morrison JL, Berry MJ, Botting KJ, Darby JRT, Frasch MG, Gatford KL, Giussani DA, Gray CL, Harding R, Herrera EA, Kemp MW, Lock MC, McMillen IC, Moss TJ, Musk GC, Oliver MH, Regnault TRH, Roberts CT, Soo JY, Tellam RL. Improving pregnancy outcomes in humans through studies in sheep. Am J Physiol Regul Integr Comp Physiol 2018; 315:R1123-R1153. [PMID: 30325659 DOI: 10.1152/ajpregu.00391.2017] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Experimental studies that are relevant to human pregnancy rely on the selection of appropriate animal models as an important element in experimental design. Consideration of the strengths and weaknesses of any animal model of human disease is fundamental to effective and meaningful translation of preclinical research. Studies in sheep have made significant contributions to our understanding of the normal and abnormal development of the fetus. As a model of human pregnancy, studies in sheep have enabled scientists and clinicians to answer questions about the etiology and treatment of poor maternal, placental, and fetal health and to provide an evidence base for translation of interventions to the clinic. The aim of this review is to highlight the advances in perinatal human medicine that have been achieved following translation of research using the pregnant sheep and fetus.
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Affiliation(s)
- Janna L Morrison
- Early Origins of Adult Health Research Group, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Mary J Berry
- Department of Paediatrics and Child Health, University of Otago , Wellington , New Zealand
| | - Kimberley J Botting
- Department of Physiology, Development, and Neuroscience, University of Cambridge , Cambridge , United Kingdom
| | - Jack R T Darby
- Early Origins of Adult Health Research Group, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Martin G Frasch
- Department of Obstetrics and Gynecology, University of Washington , Seattle, Washington
| | - Kathryn L Gatford
- Robinson Research Institute and Adelaide Medical School, University of Adelaide , Adelaide, South Australia , Australia
| | - Dino A Giussani
- Department of Physiology, Development, and Neuroscience, University of Cambridge , Cambridge , United Kingdom
| | - Clint L Gray
- Department of Paediatrics and Child Health, University of Otago , Wellington , New Zealand
| | - Richard Harding
- Department of Anatomy and Developmental Biology, Monash University , Clayton, Victoria , Australia
| | - Emilio A Herrera
- Pathophysiology Program, Biomedical Sciences Institute (ICBM), Faculty of Medicine, University of Chile , Santiago , Chile
| | - Matthew W Kemp
- Division of Obstetrics and Gynecology, University of Western Australia , Perth, Western Australia , Australia
| | - Mitchell C Lock
- Early Origins of Adult Health Research Group, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - I Caroline McMillen
- Early Origins of Adult Health Research Group, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Timothy J Moss
- The Ritchie Centre, Hudson Institute of Medical Research, Department of Obstetrics and Gynaecology, Monash University , Clayton, Victoria , Australia
| | - Gabrielle C Musk
- Animal Care Services, University of Western Australia , Perth, Western Australia , Australia
| | - Mark H Oliver
- Liggins Institute, University of Auckland , Auckland , New Zealand
| | - Timothy R H Regnault
- Department of Obstetrics and Gynecology and Department of Physiology and Pharmacology, Western University, and Children's Health Research Institute , London, Ontario , Canada
| | - Claire T Roberts
- Robinson Research Institute and Adelaide Medical School, University of Adelaide , Adelaide, South Australia , Australia
| | - Jia Yin Soo
- Early Origins of Adult Health Research Group, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
| | - Ross L Tellam
- Early Origins of Adult Health Research Group, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
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6
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Bloomfield FH. Impact of prematurity for pancreatic islet and beta-cell development. J Endocrinol 2018; 238:R161-R171. [PMID: 29895718 DOI: 10.1530/joe-18-0021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 06/12/2018] [Indexed: 12/22/2022]
Abstract
As increasing numbers of babies born preterm survive into adulthood, it is becoming clear that, in addition to the well-described risks of neurodevelopmental sequelae, there also are increased risks for non-communicable diseases, including diabetes. Epidemiological studies indicate that risks are increased even for birth at late preterm and early term gestations and for both type 1 and type 2 diabetes. Thus, factors related to preterm birth likely affect development of the fetal and neonatal beta-cell in addition to effects on peripheral insulin sensitivity. These factors could operate prior to preterm birth and be related to the underlying cause of preterm birth, to the event of being born preterm itself, to the postnatal care of the preterm neonate or to a combination of these exposures. Experimental evidence indicates that factors may be operating during all these critical periods to contribute to altered development of beta-cell mass in those born preterm. Greater understanding of how these factors impact upon development of the pancreas may lead to interventions or management approaches that mitigate the increased risk of later diabetes.
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Mrocki MM, Nguyen VB, Lombardo P, Sutherland MR, Bensley JG, Nitsos I, Allison BJ, Harding R, De Matteo R, Schneider M, Polglase GR, Black MJ. Moderate preterm birth affects right ventricular structure and function and pulmonary artery blood flow in adult sheep. J Physiol 2018; 596:5965-5975. [PMID: 29508407 DOI: 10.1113/jp275654] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 02/26/2018] [Indexed: 12/25/2022] Open
Abstract
KEY POINTS Preterm birth occurs when the heart muscle is immature and ill-prepared for the changes in heart and lung function at birth. MRI imaging studies show differences in the growth and function of the heart of young adults born preterm, with the effects more pronounced in the right ventricle. The findings of this study, conducted in sheep, showed that following moderate preterm birth the right ventricular wall was thinner in adulthood, with a reduction in the number and size of the heart muscle cells; in addition, there was impaired blood flow in the main artery leading from the right ventricle to the lungs. The findings indicate that being born only a few weeks early adversely affects the cellular structure of the right ventricle and blood flow to the lungs in adulthood. The reduced number of heart muscle cells has the potential to deleteriously affect right ventricular growth potential and function. ABSTRACT Preterm birth prematurely exposes the immature heart to the haemodynamic transition at birth, which has the potential to induce abnormal cardiac remodelling. Magnetic resonance imaging studies in young adults born preterm have shown abnormalities in the gross structure of the ventricles (particularly the right ventricle; RV), but the cellular basis of these alterations is unknown. The aim of this study, conducted in sheep, was to determine the effect of moderate preterm birth on RV cellular structure and function in early adulthood. Male singleton lambs were delivered moderately preterm (132 ± 1 days; n = 7) or at term (147 ± 1 days; n = 7). At 14.5 months of age, intra-arterial blood pressure and heart rate were measured. Pulmonary artery diameter and peak systolic blood flow were determined using ultrasound imaging, and RV stroke volume and output calculated. Cardiomyocyte number, size, nuclearity and levels of cardiac fibrosis were subsequently assessed in perfusion-fixed hearts using image analysis and stereological methods. Blood pressure (systolic, diastolic and mean), heart rate, levels of myocardial fibrosis and RV stroke volume and output were not different between groups. There was, however, a significant reduction in RV wall thickness in preterm sheep, and this was accompanied by a significant reduction in peak systolic blood flow in the pulmonary artery and in RV cardiomyocyte number. Cellular changes in the RV wall and reduced pulmonary artery blood flow following preterm birth have the potential to adversely affect cardiac and respiratory haemodynamics, especially when the cardiovascular system is physiologically or pathologically challenged.
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Affiliation(s)
- Marshall M Mrocki
- Biomedicine Discovery Institute and the Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
| | - Vivian B Nguyen
- Biomedicine Discovery Institute and the Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
| | - Paul Lombardo
- Department of Medical Imaging and Radiation Sciences, Monash University, Clayton, Victoria, Australia
| | - Megan R Sutherland
- Biomedicine Discovery Institute and the Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
| | - Jonathan G Bensley
- Biomedicine Discovery Institute and the Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
| | - Ilias Nitsos
- The Ritchie Centre, Hudson Institute of Medical Research, Monash University, Clayton, Victoria, Australia
| | - Beth J Allison
- The Ritchie Centre, Hudson Institute of Medical Research, Monash University, Clayton, Victoria, Australia
| | - Richard Harding
- Biomedicine Discovery Institute and the Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
| | - Robert De Matteo
- Biomedicine Discovery Institute and the Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
| | - Michal Schneider
- Department of Medical Imaging and Radiation Sciences, Monash University, Clayton, Victoria, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Monash University, Clayton, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - M Jane Black
- Biomedicine Discovery Institute and the Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
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Flores TJ, Nguyen VB, Widdop RE, Sutherland MR, Polglase GR, Abud HE, Black MJ. Morphology and Function of the Lamb Ileum following Preterm Birth. Front Pediatr 2018; 6:8. [PMID: 29473027 PMCID: PMC5810295 DOI: 10.3389/fped.2018.00008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/10/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND For infants born moderately/late preterm (32-37 weeks of gestation), immaturity of the intestine has the potential to impact both short- and long-term gastrointestinal function. The aim of this study conducted in sheep was to compare the morphology and smooth muscle contractility of the ileum in term and late preterm lambs. MATERIALS AND METHODS Lambs delivered preterm (132 days gestation; n = 7) or term (147 days gestation; n = 9) were milk-fed after birth and euthanased at 2 days of age. A segment of distal ileum was collected for analysis of the length and cellular composition of the villi and crypts, smooth muscle width and contractility, and mRNA expression of the cell markers Ki67, lysozyme, mucin 2, synaptophysin, chromogranin A, olfactomedin 4, axis inhibition protein 2, and leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5). RESULTS There was no difference in the proportion of inflammatory, proliferating, apoptotic, enterocyte, or goblet cells between groups, but preterm lambs exhibited a significant upregulation of the stem cell marker LGR5 (p = 0.01). Absolute villus height (term: 1,032 ± 147 µm, preterm: 651 ± 52 µm; p < 0.0001) and crypt depth (term: 153 ± 11 µm, preterm: 133 ± 17 µm; p = 0.01) were significantly shorter in the preterm ileums, with a trend (p = 0.06) for a reduction in muscularis externa width. There was no difference between groups in the contractile response to acetylcholine, but peak contractility in response to bradykinin (p = 0.02) and angiotensin II (p = 0.03) was significantly greater in the preterm lambs. CONCLUSION Findings demonstrate that the crypt-villus units are shorter in the ileum of late preterm offspring, but functionally mature with an equivalent cellular composition and normal contractile response to acetylcholine compared with term offspring. The exaggerated contractility to inflammatory mediators evident in the preterm ileum, however, may be of concern.
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Affiliation(s)
- Tracey J Flores
- The Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Vivian B Nguyen
- The Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Robert E Widdop
- Department of Pharmacology, Monash University, Clayton, VIC, Australia
| | - Megan R Sutherland
- The Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, and the Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia
| | - Helen E Abud
- The Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Mary Jane Black
- The Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
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9
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Allison BJ, Nguyen V, Yiallourou SR, Nitsos I, Black MJ, Polglase GR. The effect of sex and prematurity on the cardiovascular baroreflex response in sheep. Exp Physiol 2018; 103:9-18. [PMID: 29072344 DOI: 10.1113/ep086494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 10/13/2017] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Late preterm infants are often assumed to escape long-term morbidities known to impact earlier preterm offspring. Is this true for the cardiovascular system? What is the main finding and its importance? We show that late preterm birth is a risk factor for cardiovascular dysfunction in early adulthood and is influenced by sex. Early signs of cardiovascular dysfunction might predispose to heart disease in adulthood. Very preterm infants have an increased risk of cardiovascular disease; however, the effects of a late preterm birth on future cardiovascular function are not known. We hypothesized that after a late preterm birth, the well-described impairments in heart rate variability and baroreflex sensitivity would persist into adulthood. To test this hypothesis, sheep born preterm (0.9 gestation; nine male and seven female) or term (11 male and six female) underwent surgery at 14 months of age for insertion of femoral arterial and venous catheters and a femoral flow probe. After recovery, heart rate variability was assessed, followed by a baroreflex challenge (using the vasoactive agents phenylephrine and sodium nitroprusside) in conscious adult lambs. Our data demonstrate decreased low-frequency normalised units (LFnu) and low-frequency/high-frequency ratio in female but not male ex-preterm sheep at rest. When challenged, mature male ex-preterm sheep have an increased blood pressure response but dampened heart rate baroreflex response. We show that even a late preterm birth leads to cardiovascular dysfunction in adulthood. These early signs of cardiovascular dysfunction might underpin the later hypertension and increased risk of heart disease observed in adults born preterm. These findings are particularly important because late preterm infants are often assumed to escape the long-term morbidities known to impact on very preterm and extremely preterm offspring.
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Affiliation(s)
- Beth J Allison
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, Australia
| | - Vivian Nguyen
- Department of Anatomy and Developmental Biology and Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Stephanie R Yiallourou
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, Australia
| | - Ilias Nitsos
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Mary Jane Black
- Department of Anatomy and Developmental Biology and Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, Australia
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De Matteo R, Hodgson DJ, Bianco-Miotto T, Nguyen V, Owens JA, Harding R, Allison BJ, Polglase G, Black MJ, Gatford KL. Betamethasone-exposed preterm birth does not impair insulin action in adult sheep. J Endocrinol 2017; 232:175-187. [PMID: 27821470 DOI: 10.1530/joe-16-0300] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 11/07/2016] [Indexed: 12/13/2022]
Abstract
Preterm birth is associated with increased risk of type 2 diabetes (T2D) in adulthood; however, the underlying mechanisms are poorly understood. We therefore investigated the effect of preterm birth at ~0.9 of term after antenatal maternal betamethasone on insulin sensitivity, secretion and key determinants in adulthood, in a clinically relevant animal model. Glucose tolerance and insulin secretion (intravenous glucose tolerance test) and whole-body insulin sensitivity (hyperinsulinaemic euglycaemic clamp) were measured and tissue collected in young adult sheep (14 months old) after epostane-induced preterm (9M, 7F) or term delivery (11M, 6F). Glucose tolerance and disposition, insulin secretion, β-cell mass and insulin sensitivity did not differ between term and preterm sheep. Hepatic PRKAG2 expression was greater in preterm than in term males (P = 0.028), but did not differ between preterm and term females. In skeletal muscle, SLC2A4 (P = 0.019), PRKAA2 (P = 0.021) and PRKAG2 (P = 0.049) expression was greater in preterm than in term overall and in males, while INSR (P = 0.047) and AKT2 (P = 0.043) expression was greater in preterm than in term males only. Hepatic PRKAG2 expression correlated positively with whole-body insulin sensitivity in males only. Thus, preterm birth at 0.9 of term after betamethasone does not impair insulin sensitivity or secretion in adult sheep, and has sex-specific effects on gene expression of the insulin signalling pathway. Hence, the increased risk of T2D in preterm humans may be due to factors that initiate preterm delivery or in early neonatal exposures, rather than preterm birth per se.
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Affiliation(s)
- R De Matteo
- Department of Anatomy and Developmental BiologyMonash University, Clayton, Victoria, Australia
| | - D J Hodgson
- Robinson Research InstituteUniversity of Adelaide, Adelaide, South Australia, Australia
- Adelaide Medical SchoolUniversity of Adelaide, Adelaide, South Australia, Australia
| | - T Bianco-Miotto
- Robinson Research InstituteUniversity of Adelaide, Adelaide, South Australia, Australia
- School of AgricultureFood and Wine, University of Adelaide, Adelaide, South Australia, Australia
| | - V Nguyen
- Department of Anatomy and Developmental BiologyMonash University, Clayton, Victoria, Australia
| | - J A Owens
- Robinson Research InstituteUniversity of Adelaide, Adelaide, South Australia, Australia
- Adelaide Medical SchoolUniversity of Adelaide, Adelaide, South Australia, Australia
| | - R Harding
- Department of Anatomy and Developmental BiologyMonash University, Clayton, Victoria, Australia
| | - B J Allison
- Department of Obstetrics & GynaecologyMonash University, Clayton, Victoria, Australia
- The Ritchie CentreHudson Institute of Medical Research, Clayton, Victoria, Australia
| | - G Polglase
- Department of Obstetrics & GynaecologyMonash University, Clayton, Victoria, Australia
- The Ritchie CentreHudson Institute of Medical Research, Clayton, Victoria, Australia
| | - M J Black
- Department of Anatomy and Developmental BiologyMonash University, Clayton, Victoria, Australia
| | - K L Gatford
- Robinson Research InstituteUniversity of Adelaide, Adelaide, South Australia, Australia
- Adelaide Medical SchoolUniversity of Adelaide, Adelaide, South Australia, Australia
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