title: High plasma retinol binding protein 4 (RBP4) is associated with systemic inflammation independently of low RBP4 adipose expression and is normalized by transplantation in nonobese, nondiabetic patients with chronic kidney disease.
abstract: OBJECTIVE
  Adipose-secreted retinol binding protein 4 (RBP4) circulates in free (active) and transthyretin (TTR)-bound forms and may be associated with obesity-related inflammation. Potential involvement of plasma and adipose RBP4 in systemic inflammation in the absence of obesity and diabetes is unknown. Inflammation reduces survival in chronic kidney disease (CKD) [particularly in maintenance haemodialysis (MHD)], and plasma RBP4 may increase with renal dysfunction. We investigated (i) potential associations between RBP4 and inflammation in CKD and (ii) the role of adipose tissue in this putative interaction.
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  Nonobese, nondiabetic patients with CKD undergoing conservative (CT: n = 10) or MHD treatment (n = 25) and healthy control subjects (C: n = 11). Renal transplant recipients (n = 5) were studied to further assess the impact of restored near-normal renal function.
  
  
  METHODS
  Plasma RBP4, TTR and C-reactive protein (CRP), adipose RBP4 expression.
  
  
  RESULTS
  Plasma RBP4, TTR and CRP were highest in MHD (P < 0·05). Adipose RBP4 mRNA was, however, comparably low in CT and MHD (P < 0·05 vs C), and all parameters were normalized in transplant recipients (P < 0·05 vs MHD). In all subjects (n = 51), creatinine and TTR (P < 0·05) but not adipose RBP4 mRNA were associated with plasma RBP4. Plasma RBP4 but not its adipose expression was in turn associated positively (P < 0·05) with CRP independently of creatinine-TTR.
  
  
  CONCLUSIONS
  High plasma RBP4 and inflammation are clustered in CKD in the absence of obesity and diabetes and are normalized by transplantation. Adipose RBP4 expression is not involved in plasma RBP4 elevation, which appears to be mainly because of passive accumulation, or in CKD-associated inflammation.
authors.affiliation: Clinica Medica, Department of Medical, Technological and Translational Sciences, University of TriesteDivision of Nephrology, Azienda Ospedaliero-Universitaria Ospedali Riuniti, TriesteDivision of Nephrology, Ospedale S. Maria della Misericordia, Rovigo, Italy.
authors.forename: Rocco
authors.initials: R
authors.lastname: Barazzoni
authors.forename: Michela
authors.initials: M
authors.lastname: Zanetti
authors.forename: Annamaria
authors.initials: A
authors.lastname: Semolic
authors.forename: Alessia
authors.initials: A
authors.lastname: Pirulli
authors.forename: Maria Rosa
authors.initials: MR
authors.lastname: Cattin
authors.forename: Gianni
authors.initials: G
authors.lastname: Biolo
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bosutti
authors.forename: Giovanni
authors.initials: G
authors.lastname: Panzetta
authors.forename: Annamaria
authors.initials: A
authors.lastname: Bernardi
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Guarnieri
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000378:metabolism*; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D006435:Renal Dialysis; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000378:metabolism*; D054839:Retinol-Binding Proteins, Plasma / Q000378:metabolism*
chemical_list: C101326:RBP4 protein, human; D012333:RNA, Messenger; D054839:Retinol-Binding Proteins, Plasma