Nt-proANP in plasma, a marker of salt sensitivity, is reduced in type 2 diabetes patients.
OBJECTIVE
We recently showed that plasma concentration of N-terminal atrial natriuretic peptide (Nt-proANP) is strongly directly related to salt sensitivity. The aims of the present study were to test (i) whether plasma concentration of N-terminal brain natriuretic peptide (Nt-proBNP) is related to salt sensitivity and (ii) whether Nt-proANP, as a marker of salt sensitivity, differs between type 2 diabetes patients and nondiabetic subjects without a history of coronary heart disease.


METHODS
Nt-proBNP was determined in 30 Swedish normal subjects with heredity for primary hypertension and salt sensitivity was defined as the difference between mean arterial blood pressure after 1 week on a high-salt diet (240 mmol day(-1)) and 1 week on a low-salt diet (10 mmol day(-1)). Nt-proANP was measured in 253 patients with type 2 diabetes and in 230 nondiabetic subjects aged 40-70 years, all without a history of coronary heart disease.


RESULTS
Amongst the 30 subjects, in whom salt sensitivity was directly measured, Nt-proBNP was not correlated with salt sensitivity (R=-0.18, P=0.35). Nt-proANP (median, interquartile range) was lower in patients with type 2 diabetes (505, 387-661 pmol L(-1)) than in nondiabetic subjects (536, 421-696 pmol L(-1)) (P=0.02). In a multiple regression analysis heart rate (P <0.00001), diastolic blood pressure (P=0.02) and diabetes status (P=0.02) were inversely related whereas age (P <0.00001), cystatin C (P=0.0006), hypertension treatment (P=0.002) and female sex (P=0.006) were directly related to ln(Nt-proANP).


CONCLUSIONS
In contrast to Nt-proANP, Nt-proBNP is not related to salt sensitivity. Salt sensitivity, as estimated by Nt-proANP, seems to be reduced in type 2 diabetes.
Melander
O
O
Department of Endocrinology, Malmö University Hospital, Lund University, Malmö, Sweden. olle.melander@endo.mas.lu.se
Frandsen
E
E
Magnusson
M
M
Grubb
A
A
Jovinge
S
S
Groop
L
L
D009320:Atrial Natriuretic Factor / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000235:genetics; D003925:Diabetic Angiopathies / Q000097:blood* / Q000235:genetics; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000235:genetics; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain; D009419:Nerve Tissue Proteins / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D011498:Protein Precursors / Q000097:blood; D017673:Sodium Chloride, Dietary / Q000378:metabolism*
D015415:Biomarkers; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; D011498:Protein Precursors; D017673:Sodium Chloride, Dietary; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor