title: Circulating bile salt-dependent lipase originates from the pancreas via intestinal transcytosis.
abstract: OBJECTIVE
  Bile salt-dependent lipase (BSDL) has been detected in human blood, where it is assumed to play a substantial role in atherosclerosis. The origin of this circulating enzyme is unknown. The aim of this study was to show that blood BSDL originates from pancreatic exocrine secretions via a transcytotic motion across the intestinal epithelium.
  
  
  METHODS
  Fluorescein isothiocyanate- or [(125)I]-labeled human pancreatic BSDL was instilled into the lumen of intestinal loops of the rat, and combined biochemical and immunocytochemical investigations were performed in intestinal cells and in the blood of these animals.
  
  
  RESULTS
  In vivo pancreatic BSDL is internalized by duodenal enterocytes. The pancreatic enzyme was associated with microvilli and present in endocytic vesicles and Golgi apparatus as well as along the basolateral membrane of enterocytes. It was also detected in intestinal interstitial spaces. Radiolabeled pancreatic BSDL internalized by the duodenal epithelium is the one further detected in circulation. The radiolabeled protein was immunoprecipitated from plasma and had a 100-kilodalton molecular mass compatible with native pancreatic BSDL. In blood, BSDL was mainly associated with low-density lipoproteins.
  
  
  CONCLUSIONS
  These in vivo data show that BSDL, normally present in blood, originates from exocrine pancreatic secretion and support the pathophysiologic relevance of BSDL transcytosis through the intestinal mucosa cell lining. Based on this, the implication of circulating BSDL in atherosclerosis merits careful attention.
authors.affiliation: INSERM U559, Unité de Recherche de Physiopathologie des Cellules Epithéliales and EA 3289, Université de la Mediterranée, Faculté de Médecine-Timone, Marseilles, France. Nadine.Bruneau@medecine.univ-mrs.fr
authors.forename: Nadine
authors.initials: N
authors.lastname: Bruneau
authors.forename: Moïse
authors.initials: M
authors.lastname: Bendayan
authors.forename: Diane
authors.initials: D
authors.lastname: Gingras
authors.forename: Lucien
authors.initials: L
authors.lastname: Ghitescu
authors.forename: Emile
authors.initials: E
authors.lastname: Levy
authors.forename: Dominique
authors.initials: D
authors.lastname: Lombardo
mesh_terms: D000042:Absorption; D000818:Animals; D002417:Cattle; D020895:Enterocytes / Q000378:metabolism*; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D008074:Lipoproteins / Q000378:metabolism; D008297:Male; D010179:Pancreas / Q000378:metabolism*; D010189:Pancreatic Juice / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D002787:Sterol Esterase / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics; D013997:Time Factors
chemical_list: D005456:Fluorescent Dyes; D008074:Lipoproteins; C054784:bile salt-stimulated lipase; D002787:Sterol Esterase; D016650:Fluorescein-5-isothiocyanate