title: Adrenomedullin in peritoneal effluent expressed by peritoneal mesothelial cells.
abstract: BACKGROUND
  Adrenomedullin (AM) possesses vasodilative and cell-protective properties. Glycine combines with the C-terminal of AM to form mature, physiologically active AM (mAM). AM is reportedly induced by high glucose condition in vascular endothelial or smooth muscle cells; however, little is known on how AM is activated by amidation. To investigate the behavior of AM in patients undergoing peritoneal dialysis (PD), the concentrations of AM, mAM and CA125 were measured. The mAM to AM ratio (mAM/AM ratio) was also evaluated as a marker of amidation activity.
  
  
  METHODS
  Twenty patients were recruited for this study. The effluent at the time of the peritoneal equilibration test was collected and AM, mAM and CA125 concentrations were measured. The expression of AM in peritoneal mesothelial cells (PMCs) collected from effluent was also examined with an indirect immunofluorescent method.
  
  
  RESULTS
  Mean values of AM and mAM in effluent were 18.1 ± 1.6 and 4.1 ± 0.3 fmol/mL, respectively. In plasma, they were 42.6 ± 3.3 and 5.6 ± 0.6 fmol/mL, respectively. AM concentrations in effluent did not correlate with plasma AM level but correlated well with the dialysate-to-plasma ratio of creatinine (D/P ratio of creatinine). Moreover, in 7 of 20 cases, concentrations of the mAM and mAM/AM ratio in effluent were higher than in plasma. In effluent, AM concentration but not the mAM/AM ratio correlated with CA125 concentration. Immunocytological study revealed diffuse, cytoplasmic expression of AM in PMCs which were collected from effluent during PD.
  
  
  CONCLUSIONS
  AM is expressed by PMCs and actively amidated in the abdominal cavity of patients undergoing PD.
authors.affiliation: Division of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, 1981 Kamoda, Kawagoe, Saitama, 350-8550, Japan, rikakono@saitama-med.ac.jp.
authors.forename: Rika
authors.initials: R
authors.lastname: Kono
authors.forename: Koichi
authors.initials: K
authors.lastname: Kanozawa
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Shimosawa
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Tayama
authors.forename: Akihiko
authors.initials: A
authors.lastname: Matsuda
authors.forename: Hajime
authors.initials: H
authors.lastname: Hasegawa
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Mitarai
mesh_terms: D053607:Adrenomedullin / Q000097:blood / Q000378:metabolism*; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D018394:CA-125 Antigen / Q000378:metabolism; D003404:Creatinine / Q000097:blood / Q000378:metabolism; D015314:Dialysis Solutions / Q000378:metabolism / Q000627:therapeutic use*; D004848:Epithelium / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008875:Middle Aged; D010530:Peritoneal Dialysis; D010537:Peritoneum / Q000378:metabolism*; D016896:Treatment Outcome
chemical_list: C507862:ADM protein, human; D015415:Biomarkers; D018394:CA-125 Antigen; D015314:Dialysis Solutions; C451759:MUC16 protein, human; D008565:Membrane Proteins; D053607:Adrenomedullin; D003404:Creatinine
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