title: Normoalbuminuric type 1 diabetic patients with retinopathy have an impaired tubular response to desmopressin: its relationship with plasma endothelin-1.
abstract: OBJECTIVE
  The aim of the study was to evaluate whether normoalbuminuric type 1 diabetic patients with diabetic retinopathy (DR) have an impaired tubular response to desmopressin (dDAVP, a synthetic analog of vasopressin) administration, and its relationship with plasma and urine endothelin-1 (ET-1) levels.
  
  
  METHODS
  This was an interventional case-control study.
  
  
  METHODS
  The study was conducted at a referral center.
  
  
  METHODS
  Fifteen normoalbuminuric type 1 diabetic patients with DR were compared with 30 normoalbuminuric type 1 diabetic patients without DR. Both groups were matched by age, gender, body mass index, glycosylated hemoglobin, and the main laboratory markers of kidney function.
  
  
  METHODS
  After a 12-h period of water deprivation, dDAVP (0.3 microg/kg) was infused over 20 min. Urine was collected at baseline and 1, 2, and 3 h after dDAVP administration. ET-1 was assessed by ELISA.
  
  
  RESULTS
  dDAVP induced a lower rise in urine osmolality in patients with DR (from 650 +/- 206 to 754 +/- 224 mosmol/kg; P = 0.02) than in diabetic patients without DR (from 714 +/- 194 to 905 +/- 163 mosmol/kg; P < 0.0001). In addition, fractional excretion of Na+ decreased in patients without DR (from 0.45 +/- 0.30 to 0.29 +/- 0.29%; P = 0.04) but not in the diabetic patients with DR (from 0.36 +/- 0.22 to 0.36 +/- 0.40%; P = 0.96). Plasma ET-1 levels were inversely correlated with the response of urinary osmolality after dDAVP administration (r = -0.62; P = 0.008).
  
  
  CONCLUSIONS
  Normoalbuminuric type 1 diabetic patients with DR have impaired renal response to dDAVP that is related to plasma ET-1 levels. Further studies are required to elucidate whether this tubular resistance to dDAVP might favor dehydration in these patients.
authors.affiliation: Centro de Investigación Biomédica En Red de Diabetes y Enfermedades Metabólicas, Diabetes Research Unit, Institut de Recerca Hospital Universitari Vall d'Hebron, Universitat Autònoma de Barcelona, Barcelona 08035, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Hernández
authors.forename: Beatriz
authors.initials: B
authors.lastname: Rodríguez
authors.forename: Eladio
authors.initials: E
authors.lastname: Losada
authors.forename: Lidia
authors.initials: L
authors.lastname: Corraliza
authors.forename: Marta
authors.initials: M
authors.lastname: García-Ramírez
authors.forename: Rafael
authors.initials: R
authors.lastname: Simó
mesh_terms: D000328:Adult; D000419:Albuminuria / Q000150:complications; D003404:Creatinine / Q000652:urine; D003894:Deamino Arginine Vasopressin / Q000494:pharmacology*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000150:complications / Q000503:physiopathology / Q000652:urine; D003930:Diabetic Retinopathy / Q000097:blood* / Q000503:physiopathology / Q000652:urine; D019332:Endothelin-1 / Q000097:blood* / Q000652:urine; D005260:Female; D006801:Humans; D007684:Kidney Tubules / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D055815:Young Adult
chemical_list: D019332:Endothelin-1; D003404:Creatinine; D003894:Deamino Arginine Vasopressin