title: High concentration of leptin stimulates myeloid differentiation from human bone marrow CD34+ progenitors: potential involvement in leukocytosis of obese subjects.
abstract: OBJECTIVE
  As well as its involvement in control of adipose mass and body energy balance, several reports suggest a link between leptin and hemopoiesis. To test its putative role in human hemopoiesis, we developed a homologous system, ie recombinant human leptin treatment of purified CD34+ progenitors from adult human bone marrow.
  
  
  RESULTS
  Leptin (50-100 ng/ml) significantly stimulated the appearance of granulocyte-macrophage colonies in the presence or absence of erythropoietin. The concentration of leptin required for this effect was rather high but within the range of plasma leptin levels observed in obesity. Two results further support the hypothesis that leptin may be involved in the leukocytosis associated with obesity: (i) leptin concentrations in bone marrow and plasma of subjects studied were highly correlated; (ii) leptin and leukocyte count were correlated only in obese subjects. Paracrine effects of locally released leptin from bone marrow adipocytes could also be involved in the regulation of hemopoiesis, a hypothesis supported by marrow immunocytochemistry revealing the close association of CD34+ cells with adipocytes and by previous demonstration that leptin is secreted at a high level by these cells.
  
  
  CONCLUSIONS
  These results indicate that leptin acts on human multilineage CD34+ cells and that high plasma leptin levels associated with obesity could participate in the differentiation of granulocytes from hemopoietic progenitors.
authors.affiliation: UPRESA CNRS 5018, UPS, Hôpital Toulouse Rangueil, France. laharrag@rangueil.inserm.fr
authors.forename: P
authors.initials: P
authors.lastname: Laharrague
authors.forename: J M
authors.initials: JM
authors.lastname: Oppert
authors.forename: P
authors.initials: P
authors.lastname: Brousset
authors.forename: J P
authors.initials: JP
authors.lastname: Charlet
authors.forename: A
authors.initials: A
authors.lastname: Campfield
authors.forename: A M
authors.initials: AM
authors.lastname: Fontanilles
authors.forename: B
authors.initials: B
authors.lastname: Guy-Grand
authors.forename: J X
authors.initials: JX
authors.lastname: Corberand
authors.forename: L
authors.initials: L
authors.lastname: Pénicaud
authors.forename: L
authors.initials: L
authors.lastname: Casteilla
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D018952:Antigens, CD34 / Q000032:analysis; D016022:Case-Control Studies; D002478:Cells, Cultured; D005260:Female; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D020738:Leptin / Q000097:blood / Q000378:metabolism* / Q000494:pharmacology; D007958:Leukocyte Count; D007964:Leukocytosis / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D012044:Regression Analysis
chemical_list: D018952:Antigens, CD34; D020738:Leptin; D011994:Recombinant Proteins