title: Is a β cell a β cell?
abstract: OBJECTIVE
  This report examines recent publications identifying phenotypic and functional heterogeneity among pancreatic β cells and investigating their potential roles in normal and abnormal islet function. The development of new methods and tools for the study of individual islet cells has produced a surge of interest in this topic.
  
  
  RESULTS
  Studies of β cell maturation and pregnancy-induced proliferation have identified changes in serotonin and transcription factors SIX2/3 expression as markers of temporal heterogeneity. Structural and functional heterogeneity in the form of functionally distinct 'hub' and 'follower' β cells was found in mouse islets. Heterogeneous expression of Fltp (in mouse β cells) and ST8SIA1 and CD9 (in human β cells) were associated with distinct functional potential. Several impressive reports describing the transcriptomes of individual β cells were also published in recent months. Some of these reveal previously unknown β cell subpopulations.
  
  
  CONCLUSIONS
  A wealth of information on functional and phenotypic heterogeneity has been collected recently, including the transcriptomes of individual β cells and the identities of functionally distinct β cell subpopulations. Several studies suggest the existence of two broad categories: a more proliferative but less functional and a less proliferative but more functional β cell type. The identification of functionally distinct subpopulations and their association with type 2 diabetes underlines the potential clinical importance of these investigations.
authors.affiliation: aProgram in Molecular Medicine, Diabetes Center of Excellence, University of Massachusetts Medical School, Worcester, Massachusetts bOregon Stem Cell Center, Papé Family Pediatric Institute, Oregon Health & Science University, Portland, Oregon, USA.
authors.forename: Chaoxing
authors.initials: C
authors.lastname: Yang
authors.forename: Feorillo
authors.initials: F
authors.lastname: Galivo
authors.forename: Craig
authors.initials: C
authors.lastname: Dorrell
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D006801:Humans; D050417:Insulin-Secreting Cells / Q000378:metabolism / Q000502:physiology*; D007515:Islets of Langerhans / Q000166:cytology* / Q000378:metabolism / Q000473:pathology
chemical_list: D015415:Biomarkers