The mature form of adrenomedullin correlates with brain natriuretic peptide in plasma of chronic hemodialysis patients.
OBJECTIVE
Adrenomedullin (AM), a hypotensive and natriuretic peptide, consists of an amidated mature form (mAM) and an intermediate form in human plasma, of which only mAM exerts biological activity. Like atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), plasma levels of mAM are reported to be significantly elevated in hemodialysis (HD) patients, suggesting that mAM may be stimulated partly by increased body fluid volume in a manner similar to the natriuretic peptides. Here, we examined the relationship between mAM levels and ANP or BNP levels and the effect of HD on plasma mAM in HD patients.


METHODS
We measured plasma levels of mAM, total AM (tAM), ANP and BNP before and after HD in patients on long-term HD (n = 22, mean age 56.3 +/- 3.2 years) using radioimmunoassay.


RESULTS
Baseline mAM (2.7 +/- 0.3 fmol/ml) and tAM (23.6 +/- 2.0 fmol/ml) were significantly higher in HD patients than in healthy subjects (1.1 +/- 0.2 fmol/ml, 9.0 +/- 2.1 fmol/ml, respectively). HD significantly reduced the levels to 1.2 +/- 0.2 fmol/ml and 13.8 +/- 1.4 fmol/ml, respectively, although tAM levels were still elevated compared to healthy subjects. Similar plasma ANP and BNP levels were obtained in HD patients. There were significant correlations between mAM and tAM levels before and after HD and between HD-induced changes in mAM and tAM levels. In the pre-HD state, levels of both mAM and tAM correlated significantly with BNP levels, but the correlation of BNP with mAM was closer than that with tAM. In contrast, no correlations were observed between the 2 forms of AM and ANP. Changes in mAM levels during HD also correlated significantly with BNP but not ANP levels, although the changes in tAM did not correlate with those of the 2 natriuretic peptides.


CONCLUSIONS
Our results suggest that the secretion/metabolism of mAM may be regulated in a manner similar to that of BNP in HD patients.
Suda
T
T
Second Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine, Kitakyushu, Japan.
Osajima
A
A
Iwamoto
M
M
Anai
H
H
Tamura
M
M
Kabashima
N
N
Ota
T
T
Watanabe
Y
Y
Kanegae
K
K
Okazaki
M
M
Nakashima
Y
Y
D053607:Adrenomedullin; D000328:Adult; D009320:Atrial Natriuretic Factor / Q000097:blood*; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D010455:Peptides / Q000097:blood*; D011863:Radioimmunoassay; D006435:Renal Dialysis; D012720:Severity of Illness Index; D013997:Time Factors; D014665:Vasodilator Agents / Q000097:blood*
D010455:Peptides; D014665:Vasodilator Agents; D020097:Natriuretic Peptide, Brain; D053607:Adrenomedullin; D009320:Atrial Natriuretic Factor