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Baldelomar EJ, Morozov D, Wilson LD, Eldeniz C, An H, Charlton JR, Bauer AQ, Keilholz SD, Hulbert ML, Bennett KM. Resting-state MRI reveals spontaneous physiological fluctuations in the kidney and tracks diabetic nephropathy in rats. Am J Physiol Renal Physiol 2024; 327:F113-F127. [PMID: 38660712 DOI: 10.1152/ajprenal.00423.2023] [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: 12/25/2023] [Revised: 04/16/2024] [Accepted: 04/16/2024] [Indexed: 04/26/2024] Open
Abstract
The kidneys maintain fluid-electrolyte balance and excrete waste in the presence of constant fluctuations in plasma volume and systemic blood pressure. The kidneys perform these functions to control capillary perfusion and glomerular filtration by modulating the mechanisms of autoregulation. An effect of these modulations are spontaneous, natural fluctuations in glomerular perfusion. Numerous other mechanisms can lead to fluctuations in perfusion and flow. The ability to monitor these spontaneous physiological fluctuations in vivo could facilitate the early detection of kidney disease. The goal of this work was to investigate the use of resting-state magnetic resonance imaging (rsMRI) to detect spontaneous physiological fluctuations in the kidney. We performed rsMRI of rat kidneys in vivo over 10 min, applying motion correction to resolve time series in each voxel. We observed spatially variable, spontaneous fluctuations in rsMRI signal between 0 and 0.3 Hz, in frequency bands associated with autoregulatory mechanisms. We further applied rsMRI to investigate changes in these fluctuations in a rat model of diabetic nephropathy. Spectral analysis was performed on time series of rsMRI signals in the kidney cortex and medulla. The power from spectra in specific frequency bands from the cortex correlated with severity of glomerular pathology caused by diabetic nephropathy. Finally, we investigated the feasibility of using rsMRI of the human kidney in two participants, observing the presence of similar, spatially variable fluctuations. This approach may enable a range of preclinical and clinical investigations of kidney function and facilitate the development of new therapies to improve outcomes in patients with kidney disease.NEW & NOTEWORTHY This work demonstrates the development and use of resting-state MRI to detect low-frequency, spontaneous physiological fluctuations in the kidney consistent with previously observed fluctuations in perfusion and potentially due to autoregulatory function. These fluctuations are detectable in rat and human kidneys, and the power of these fluctuations is affected by diabetic nephropathy in rats.
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Affiliation(s)
- Edwin J Baldelomar
- Mallinckrodt Institute of Radiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States
| | - Darya Morozov
- Mallinckrodt Institute of Radiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States
| | - Leslie D Wilson
- Division of Comparative Medicine, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States
| | - Cihat Eldeniz
- Mallinckrodt Institute of Radiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States
| | - Hongyu An
- Mallinckrodt Institute of Radiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States
| | - Jennifer R Charlton
- Division of Nephrology, Department of Pediatrics, University of Virginia, Charlottesville, Virginia, United States
| | - Adam Q Bauer
- Mallinckrodt Institute of Radiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States
| | - Shella D Keilholz
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States
| | - Monica L Hulbert
- Division of Pediatric Hematology/Oncology, Washington University School of Medicine in St. Louis, Missouri, United States
| | - Kevin M Bennett
- Mallinckrodt Institute of Radiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States
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Baldelomar EJ, Reichert DE, Shoghi KI, Beeman SC, Charlton JR, Strong L, Fettig N, Klaas A, Bennett KM. Mapping nephron mass in vivo using positron emission tomography. Am J Physiol Renal Physiol 2021; 320:F183-F192. [PMID: 33283644 PMCID: PMC8091936 DOI: 10.1152/ajprenal.00418.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 12/03/2020] [Accepted: 12/04/2020] [Indexed: 01/19/2023] Open
Abstract
Nephron number varies widely in humans. A low nephron endowment at birth or a loss of functioning nephrons is strongly linked to increased susceptibility to chronic kidney disease. In this work, we developed a contrast agent, radiolabeled cationic ferritin (RadioCF), to map functioning glomeruli in vivo in the kidney using positron emission tomography (PET). PET radiotracers can be detected in trace doses (<30 nmol), making them useful for rapid clinical translation. RadioCF is formed from cationic ferritin (CF) and with a radioisotope, Cu-64, incorporated into the ferritin core. We showed that RadioCF binds specifically to kidney glomeruli after intravenous injection in mice, whereas radiolabeled noncationic ferritin (RadioNF) and free Cu-64 do not. We then showed that RadioCF-PET can distinguish kidneys in healthy wild-type (WT) mice from kidneys in mice with oligosyndactylism (Os/+), a model of congenital hypoplasia and low nephron mass. The average standardized uptake value (SUV) measured by PET 90 min after injection was 21% higher in WT mice than in Os/+ mice, consistent with the higher glomerular density in WT mice. The difference in peak SUV from SUV at 90 min correlated with glomerular density in male mice from both WT and Os/+ cohorts (R2 = 0.98). Finally, we used RadioCF-PET to map functioning glomeruli in a donated human kidney. SUV within the kidney correlated with glomerular number (R2= 0.78) measured by CF-enhanced magnetic resonance imaging in the same locations. This work suggests that RadioCF-PET appears to accurately detect nephron mass and has the potential for clinical translation.
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Affiliation(s)
- Edwin J Baldelomar
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, Missouri
| | - David E Reichert
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, Missouri
| | - Kooresh I Shoghi
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, Missouri
| | - Scott C Beeman
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, Missouri
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona
| | | | - Lori Strong
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, Missouri
| | - Nikki Fettig
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, Missouri
| | - Amanda Klaas
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, Missouri
| | - Kevin M Bennett
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, Missouri
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Tedeschi A, Almagro J, Renshaw MJ, Messal HA, Behrens A, Petronczki M. Cep55 promotes cytokinesis of neural progenitors but is dispensable for most mammalian cell divisions. Nat Commun 2020; 11:1746. [PMID: 32269212 PMCID: PMC7142149 DOI: 10.1038/s41467-020-15359-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 02/27/2020] [Indexed: 12/20/2022] Open
Abstract
In mammalian cell lines, the endosomal sorting complex required for transport (ESCRT)-III mediates abscission, the process that physically separates daughter cells and completes cell division. Cep55 protein is regarded as the master regulator of abscission, because it recruits ESCRT-III to the midbody (MB), the site of abscission. However, the importance of this mechanism in a mammalian organism has never been tested. Here we show that Cep55 is dispensable for mouse embryonic development and adult tissue homeostasis. Cep55-knockout offspring show microcephaly and primary neural progenitors require Cep55 and ESCRT for survival and abscission. However, Cep55 is dispensable for cell division in embryonic or adult tissues. In vitro, division of primary fibroblasts occurs without Cep55 and ESCRT-III at the midbody and is not affected by ESCRT depletion. Our work defines Cep55 as an abscission regulator only in specific tissue contexts and necessitates the re-evaluation of an alternative ESCRT-independent cell division mechanism.
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Affiliation(s)
- Antonio Tedeschi
- Adult Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
- Cell Division and Aneuploidy Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, London, EN6 3LD, UK.
| | - Jorge Almagro
- Adult Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Matthew J Renshaw
- Advanced Light Microscopy, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Hendrik A Messal
- Adult Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Division of Molecular Pathology, Oncode Institute, Netherlands Cancer Institute, Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands
| | - Axel Behrens
- Adult Stem Cell Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Faculty of Life Sciences, King's College London, Guy's Campus, London, SE1 1UL, UK
| | - Mark Petronczki
- Cell Division and Aneuploidy Laboratory, Clare Hall Laboratories, Cancer Research UK London Research Institute, London, EN6 3LD, UK
- Boehringer Ingelheim RCV GmbH & Co KG, A-1121, Vienna, Austria
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4
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Chevalier RL. Evolution and Kidney Development: A Rosetta Stone for Nephrology. J Am Soc Nephrol 2018; 29:706-709. [PMID: 29449452 DOI: 10.1681/asn.2018010013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Robert L Chevalier
- Department of Pediatrics, University of Virginia, Charlottesville, Virginia
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Rieger A, Kemter E, Kumar S, Popper B, Aigner B, Wolf E, Wanke R, Blutke A. Missense Mutation of POU Domain Class 3 Transcription Factor 3 in Pou3f3L423P Mice Causes Reduced Nephron Number and Impaired Development of the Thick Ascending Limb of the Loop of Henle. PLoS One 2016; 11:e0158977. [PMID: 27420727 PMCID: PMC4946790 DOI: 10.1371/journal.pone.0158977] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 06/25/2016] [Indexed: 12/27/2022] Open
Abstract
During nephrogenesis, POU domain class 3 transcription factor 3 (POU3F3 aka BRN1) is critically involved in development of distinct nephron segments, including the thick ascending limb of the loop of Henle (TAL). Deficiency of POU3F3 in knock-out mice leads to underdevelopment of the TAL, lack of differentiation of TAL cells, and perinatal death due to renal failure. Pou3f3L423P mutant mice, which were established in the Munich ENU Mouse Mutagenesis Project, carry a recessive point mutation in the homeobox domain of POU3F3. Homozygous Pou3f3L423P mutants are viable and fertile. The present study used functional, as well as qualitative and quantitative morphological analyses to characterize the renal phenotype of juvenile (12 days) and aged (60 weeks) homo- and heterozygous Pou3f3L423P mutant mice and age-matched wild-type controls. In both age groups, homozygous mutants vs. control mice displayed significantly smaller kidney volumes, decreased nephron numbers and mean glomerular volumes, smaller TAL volumes, as well as lower volume densities of the TAL in the kidney. No histological or ultrastructural lesions of TAL cells or glomerular cells were observed in homozygous mutant mice. Aged homozygous mutants displayed increased serum urea concentrations and reduced specific urine gravity, but no evidence of glomerular dysfunction. These results confirm the role of POU3F3 in development and function of the TAL and provide new evidence for its involvement in regulation of the nephron number in the kidney. Therefore, Pou3f3L423P mutant mice represent a valuable research model for further analyses of POU3F3 functions, or for nephrological studies examining the role of congenital low nephron numbers.
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Affiliation(s)
- Alexandra Rieger
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Elisabeth Kemter
- Chair for Molecular Animal Breeding and Biotechnology and Laboratory for Functional Genome Analysis, Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Sudhir Kumar
- Chair for Molecular Animal Breeding and Biotechnology and Laboratory for Functional Genome Analysis, Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Bastian Popper
- Department of Anatomy and Cell Biology, Biomedical Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Bernhard Aigner
- Chair for Molecular Animal Breeding and Biotechnology and Laboratory for Functional Genome Analysis, Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Eckhard Wolf
- Chair for Molecular Animal Breeding and Biotechnology and Laboratory for Functional Genome Analysis, Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
- German Center for Diabetes Research (DZD), Helmholtz Zentrum München, Neuherberg, Germany
| | - Rüdiger Wanke
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Andreas Blutke
- Institute of Veterinary Pathology at the Centre for Clinical Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
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Baldelomar EJ, Charlton JR, Beeman SC, Hann BD, Cullen-McEwen L, Pearl VM, Bertram JF, Wu T, Zhang M, Bennett KM. Phenotyping by magnetic resonance imaging nondestructively measures glomerular number and volume distribution in mice with and without nephron reduction. Kidney Int 2016; 89:498-505. [PMID: 26535998 PMCID: PMC4854807 DOI: 10.1038/ki.2015.316] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 07/23/2015] [Accepted: 08/20/2015] [Indexed: 12/29/2022]
Abstract
Reduced nephron mass is strongly linked to susceptibility to chronic renal and cardiovascular diseases. There are currently no tools to identify nephropenia in clinical or preclinical diagnostics. Such new methods could uncover novel mechanisms and therapies for chronic kidney disease (CKD) and reveal how variation among traits can affect renal function and morphology. Here we used cationized ferritin (CF)–enhanced MRI (CFE-MRI) to investigate the relationship between glomerular number (Nglom) and volume (Vglom) in kidneys of healthy wild-type mice and mice with oligosyndactylism (Os/+), a model of congenital nephron reduction. Mice were injected with CF and perfused, and the resected kidneys were imaged with 7T MRI to detect CF-labeled glomeruli. CFE-MRI was used to measure the intrarenal distribution of individual glomerular volumes and revealed two major populations of glomeruli distinguished by size. Spatial mapping revealed that the largest glomeruli were located in the juxtamedullary region in both wild-type and Os/+ mice and the smallest population located in the cortex. Os/+ mice had about a 50% reduction and 35% increase of Nglom and Vglom, respectively, in both glomerular populations compared with wild type, consistent with glomerular hypertrophy in the Os/+ mice. Thus, we provide a foundation for whole-kidney, MRI-based phenotyping of mouse renal glomerular morphology and provide new potential for quantitative human renal diagnostics.
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Affiliation(s)
- Edwin J. Baldelomar
- University of Hawaii at Manoa, Department of Physics, Honolulu, Hawaii, USA
- University of Hawaii at Manoa, Department of Biology, Honolulu, Hawaii, USA
| | | | - Scott C. Beeman
- Washington University School of Medicine, Saint Louis, Missouri, USA
| | - Bradley D. Hann
- University of Hawaii at Manoa, Department of Molecular Biosciences and Bioengineering, Honolulu, Hawaii, USA
- University of Hawaii at Manoa, Department of Biology, Honolulu, Hawaii, USA
| | | | | | | | - Teresa Wu
- Arizona State University, Tempe, Arizona, USA
| | - Min Zhang
- Arizona State University, Tempe, Arizona, USA
| | - Kevin M. Bennett
- University of Hawaii at Manoa, Department of Biology, Honolulu, Hawaii, USA
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7
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Osei-Owusu P, Owens EA, Jie L, Reis JS, Forrester SJ, Kawai T, Eguchi S, Singh H, Blumer KJ. Regulation of Renal Hemodynamics and Function by RGS2. PLoS One 2015; 10:e0132594. [PMID: 26193676 PMCID: PMC4508038 DOI: 10.1371/journal.pone.0132594] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 06/16/2015] [Indexed: 12/16/2022] Open
Abstract
Regulator of G protein signaling 2 (RGS2) controls G protein coupled receptor (GPCR) signaling by acting as a GTPase-activating protein for heterotrimeric G proteins. Certain Rgs2 gene mutations have been linked to human hypertension. Renal RGS2 deficiency is sufficient to cause hypertension in mice; however, the pathological mechanisms are unknown. Here we determined how the loss of RGS2 affects renal function. We examined renal hemodynamics and tubular function by monitoring renal blood flow (RBF), glomerular filtration rate (GFR), epithelial sodium channel (ENaC) expression and localization, and pressure natriuresis in wild type (WT) and RGS2 null (RGS2-/-) mice. Pressure natriuresis was determined by stepwise increases in renal perfusion pressure (RPP) and blood flow, or by systemic blockade of nitric oxide synthase with L-NG-Nitroarginine methyl ester (L-NAME). Baseline GFR was markedly decreased in RGS2-/- mice compared to WT controls (5.0 ± 0.8 vs. 2.5 ± 0.1 μl/min/g body weight, p<0.01). RBF was reduced (35.4 ± 3.6 vs. 29.1 ± 2.1 μl/min/g body weight, p=0.08) while renal vascular resistance (RVR; 2.1 ± 0.2 vs. 3.0 ± 0.2 mmHg/μl/min/g body weight, p<0.01) was elevated in RGS2-/- compared to WT mice. RGS2 deficiency caused decreased sensitivity and magnitude of changes in RVR and RBF after a step increase in RPP. The acute pressure–natriuresis curve was shifted rightward in RGS2-/- relative to WT mice. Sodium excretion rate following increased RPP by L-NAME was markedly decreased in RGS2-/- mice and accompanied by increased translocation of ENaC to the luminal wall. We conclude that RGS2 deficiency impairs renal function and autoregulation by increasing renal vascular resistance and reducing renal blood flow. These changes impair renal sodium handling by favoring sodium retention. The findings provide a new line of evidence for renal dysfunction as a primary cause of hypertension.
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Affiliation(s)
- Patrick Osei-Owusu
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania, 19102, United States of America
- * E-mail:
| | - Elizabeth A. Owens
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania, 19102, United States of America
| | - Li Jie
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania, 19102, United States of America
| | - Janaina S. Reis
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania, 19102, United States of America
| | - Steven J. Forrester
- Cardiovascular Research Center and Department of Physiology, Temple University, Philadelphia, Pennsylvania, 19140, United States of America
| | - Tatsuo Kawai
- Cardiovascular Research Center and Department of Physiology, Temple University, Philadelphia, Pennsylvania, 19140, United States of America
| | - Satoru Eguchi
- Cardiovascular Research Center and Department of Physiology, Temple University, Philadelphia, Pennsylvania, 19140, United States of America
| | - Harpreet Singh
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, Pennsylvania, 19102, United States of America
| | - Kendall J. Blumer
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, 63110, United States of America
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Briffa JF, McAinch AJ, Romano T, Wlodek ME, Hryciw DH. Leptin in pregnancy and development: a contributor to adulthood disease? Am J Physiol Endocrinol Metab 2015; 308:E335-50. [PMID: 25516549 DOI: 10.1152/ajpendo.00312.2014] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Emerging research has highlighted the importance of leptin in fetal growth and development independent of its essential role in the maintenance of hunger and satiety through the modulation of neuropeptide Y and proopiomelanocortin neurons. Alterations in maternal-placental-fetal leptin exchange may modify the development of the fetus and contribute to the increased risk of developing disease in adulthood. In addition, leptin also plays an important role in reproductive functions, with plasma leptin concentrations rising in pregnant women, peaking during the third trimester. Elevated plasma leptin concentrations occur at the completion of organogenesis, and research in animal models has demonstrated that leptin is involved in the development and maturation of a number of organs, including the heart, brain, kidneys, and pancreas. Elevated maternal plasma leptin is associated with maternal obesity, and reduced fetal plasma leptin is correlated with intrauterine growth restriction. Alterations in plasma leptin during development may be associated with an increased risk of developing a number of adulthood diseases, including cardiovascular, metabolic, and renal diseases via altered fetal development and organogenesis. Importantly, research has shown that leptin antagonism after birth significantly reduces maturation of numerous organs. Conversely, restoration of the leptin deficiency after birth in growth-restricted animals restores the offspring's body weight and improves organogenesis. Therefore, leptin appears to play a major role in organogenesis, which may adversely affect the risk of developing a number of diseases in adulthood. Therefore, greater understanding of the role of leptin during development may assist in the prevention and treatment of a number of disease states that occur in adulthood.
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Affiliation(s)
- Jessica F Briffa
- Department of Physiology, University of Melbourne, Parkville, Australia
| | - Andrew J McAinch
- Centre for Chronic Disease Prevention and Management, College of Health and Biomedicine, Victoria University, St. Albans, Australia; and
| | - Tania Romano
- Department of Human Biosciences, Latrobe University, Bundoora, Australia
| | - Mary E Wlodek
- Department of Physiology, University of Melbourne, Parkville, Australia
| | - Deanne H Hryciw
- Department of Physiology, University of Melbourne, Parkville, Australia;
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