title: Biological optimization, the Goldilocks principle, and how much is lagom in the preimplantation embryo.
abstract: The quiet embryo hypothesis postulates that early embryo viability is associated with a relatively low metabolism (Leese, 2002 BioEssays 24: 845-849). This proposal is re-visited here using retrospective and prospective data on the metabolic activity and kinetics of preimplantation development alongside the concept that an optimal range of such indices and of energetic efficiency influences embryogenesis. It is concluded that these considerations may be rationalized by proposing the existence of a "Goldilocks zone," or as it is known in Sweden, of lagom-meaning "just the right amount"-within which embryos with maximum developmental potential can be categorized. Mol. Reprod. Dev. 83: 748-754, 2016 © 2016 Wiley Periodicals, Inc.
authors.affiliation: Centre for Cardiovascular Metabolic Research, Hull York Medical School, University of Hull, Hull, United Kingdom. henry.leese@hyms.ac.uk.
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Leese
authors.affiliation: Medecine et Biologie de la Reproduction, Université de Tours, Tours, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Guerif
authors.affiliation: Centre for Cardiovascular Metabolic Research, Hull York Medical School, University of Hull, Hull, United Kingdom.
authors.forename: Victoria
authors.initials: V
authors.lastname: Allgar
authors.affiliation: Department of Reproductive Medicine, Central Manchester University Hospitals NHS Foundation Trust, St Mary's Hospital, Manchester, United Kingdom.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Brison
authors.affiliation: Reproductive Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Kersti
authors.initials: K
authors.lastname: Lundin
authors.affiliation: Centre for Cardiovascular Metabolic Research, Hull York Medical School, University of Hull, Hull, United Kingdom.
authors.forename: Roger G
authors.initials: RG
authors.lastname: Sturmey
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism*; D010064:Embryo Implantation / Q000502:physiology*; D006801:Humans
keywords: biological optimization; metabolism; nutrition; preimplantation