title: Expression of leptin and its long form receptor at the porcine maternal-fetal interface: contrasting healthy and arresting conceptus attachment sites during early and mid-pregnancy.
abstract: BACKGROUND
  It is well established that spontaneous conceptus loss in swine is associated with an imbalance of both angiogenic and immunological factors. Leptin (LEP), a metabolic hormone, has also been implicated in the promotion of angiogenesis. In this study, LEP and its long form receptor (OB-Rb) were evaluated during porcine pregnancy to assess their basal level of expression and their potential role in conceptus development.
  
  
  METHODS
  Expression and secretion of LEP and OB-Rb were quantified in the endometrium of non-pregnant (n = 5), and in the endometrium and chorioallantoic membrane (CAM) of pregnant sows (parity 2 to 5) at gestational days (gd) 20 (n = 8) and 50 (n = 8). Data were analyzed by a 3-way ANOVA testing the effects of conceptus health, tissue type and gestational day.
  
  
  RESULTS
  Leptin and OB-Rb transcripts were significantly higher (P < 0.05) in pregnant than in non-pregnant sows. Significantly greater LEP (P < 0.001) was detected in the endometrial tissue at gd20 compared with gd50. At the protein level, the lowest LEP expression (P < 0.01) was detected in the CAM at gd50, while OB-Rb protein was significantly lower (P < 0.01) at gd50 in the CAM than in the endometrium collected from gd20 and gd50 conceptus attachment sites. Immunofluorescence staining confirmed the expression of these proteins at both gestational days and in both tissue types.
  
  
  CONCLUSIONS
  Changes in the expression patterns of LEP and OB-Rb between gd20 and gd50 suggest a role for the LEP/OB-R complex at the early stages of porcine pregnancy, possibly affecting the attachment process. Further mechanistic studies are warranted to understand the specific role of leptin in porcine pregnancy.
authors.forename: Ashley
authors.initials: A
authors.lastname: Kerr
authors.forename: Rami T
authors.initials: RT
authors.lastname: Kridli
authors.forename: Kasra
authors.initials: K
authors.lastname: Khalaj
authors.forename: Jocelyn M
authors.initials: JM
authors.lastname: Wessels
authors.forename: Ann
authors.initials: A
authors.lastname: Hahnel
authors.affiliation: Department of Biomedical Sciences, University of Guelph, Guelph, Ontario, Canada. tayadec@queensu.ca.
authors.forename: Chandrakant
authors.initials: C
authors.lastname: Tayade
mesh_terms: D000818:Animals; D017849:Animals, Inbred Strains; D049033:Chorioallantoic Membrane / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D004717:Endometrium / Q000166:cytology / Q000378:metabolism*; D005260:Female; D047109:Fetal Development; D005455:Fluorescent Antibody Technique / Q000662:veterinary; D018507:Gene Expression Regulation, Developmental; D007315:Insemination, Artificial / Q000662:veterinary; D020738:Leptin / Q000235:genetics / Q000378:metabolism*; D009864:Ontario; D010929:Placentation; D011247:Pregnancy; D011255:Pregnancy Maintenance; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D054411:Receptors, Leptin / Q000235:genetics / Q000378:metabolism*; D013047:Specific Pathogen-Free Organisms; D034421:Sus scrofa / Q000502:physiology*
chemical_list: D020738:Leptin; D011498:Protein Precursors; D012333:RNA, Messenger; D054411:Receptors, Leptin