title: Neuregulin-1 Administration Protocols Sufficient for Stimulating Cardiac Regeneration in Young Mice Do Not Induce Somatic, Organ, or Neoplastic Growth.
abstract: We previously developed and validated a strategy for stimulating heart regeneration by administration of recombinant neuregulin (rNRG1), a growth factor, in mice. rNRG1 stimulated proliferation of heart muscle cells, cardiomyocytes, and was most effective when administration began during the neonatal period. Our results suggested the use of rNRG1 to treat pediatric patients with heart failure. However, administration in this age group may stimulate growth outside of the heart.
  
  
  
  NRG1 and ErbB receptor expression was determined by RT-PCR. rNRG1 concentrations in serum were quantified by ELISA. Mice that received protocols of recombinant neuregulin1-β1 administration (rNRG1, 100 ng/g body weight, daily subcutaneous injection for the first month of life), previously shown to induce cardiac regeneration, were examined at pre-determined intervals. Somatic growth was quantified by weighing. Organ growth was quantified by MRI and by weighing. Neoplastic growth was examined by MRI, visual inspection, and histopathological analyses. Phospho-ERK1/2 and S6 kinase were analyzed with Western blot and ELISA, respectively.
  
  
  
  Lung, spleen, liver, kidney, brain, and breast gland exhibited variable expression of the NRG1 receptors ErbB2, ErbB3, ErbB4, and NRG1. Body weight and tibia length were not altered in mice receiving rNRG1. MRI showed that administration of rNRG1 did not alter the volume of the lungs, liver, kidneys, brain, or spinal cord. Administration of rNRG1 did not alter the weight of the lungs, spleen, liver, kidneys, or brain. MRI, visual inspection, and histopathological analyses showed no neoplastic growth. Follow-up for 6 months showed no alteration of somatic or organ growth. rNRG1 treatment increased the levels of phospho-ERK1/2, but not phospho-S6 kinase.
  
  
  
  Administration protocols of rNRG1 for stimulating cardiac regeneration in mice during the first month of life did not induce unwanted growth effects. Further studies may be required to determine whether this is the case in a corresponding human population.
authors.affiliation: Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, United States of America.|Department of Pediatrics, University of Pittsburgh, and Richard King Mellon Institute for Pediatric Research and Division of Pediatric Cardiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, United States of America.
authors.forename: Balakrishnan
authors.initials: B
authors.lastname: Ganapathy
authors.affiliation: Department of Pediatrics, University of Pittsburgh, and Richard King Mellon Institute for Pediatric Research and Division of Pediatric Cardiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, United States of America.|Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15260, United States of America.
authors.forename: Nikitha
authors.initials: N
authors.lastname: Nandhagopal
authors.affiliation: Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, United States of America.|Department of Pediatrics, Harvard Medical School, Boston, MA 02115, United States of America.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Polizzotti
authors.affiliation: Pre-clinical MRI Core, Beth Israel Deaconess Medical Center, Boston, MA 02115, United States of America.
authors.forename: David
authors.initials: D
authors.lastname: Bennett
authors.affiliation: Department of Pediatrics, University of Pittsburgh, and Richard King Mellon Institute for Pediatric Research and Division of Pediatric Cardiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, United States of America.|Interdisciplinary Biomedical Graduate Program, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, United States of America.
authors.forename: Alparslan
authors.initials: A
authors.lastname: Asan
authors.affiliation: Department of Developmental Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15224, United States of America.|Rangos Research Center Animal Imaging Core, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, United States of America.
authors.forename: Yijen
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, United States of America.|Department of Pediatrics, University of Pittsburgh, and Richard King Mellon Institute for Pediatric Research and Division of Pediatric Cardiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, United States of America.|Department of Pediatrics, Harvard Medical School, Boston, MA 02115, United States of America.|McGowan Institute for Regenerative Medicine, Pittsburgh, PA 15219, United States of America.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Kühn
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000201:enzymology; D051379:Mice; D009024:Morphogenesis / Q000187:drug effects*; D009369:Neoplasms / Q000473:pathology*; D020890:Neuregulin-1 / Q000008:administration & dosage* / Q000097:blood / Q000235:genetics / Q000494:pharmacology*; D009929:Organ Size / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D011994:Recombinant Proteins / Q000494:pharmacology; D012038:Regeneration / Q000187:drug effects*; D019893:Ribosomal Protein S6 Kinases / Q000378:metabolism
chemical_list: D020890:Neuregulin-1; D011994:Recombinant Proteins; D066246:ErbB Receptors; D019893:Ribosomal Protein S6 Kinases; D048049:Extracellular Signal-Regulated MAP Kinases