Parallel increase in urinary excretion rates of immunoglobulin G, ceruloplasmin, transferrin, and orosomucoid in normoalbuminuric type 2 diabetic patients.
OBJECTIVE
Increased urinary excretions of several plasma proteins with different molecular radii <55 A and different isoelectric points (pI), such as IgG, ceruloplasmin, transferrin, and orosomucoid, have been independently reported to precede the development of microalbuminuria in diabetic patients. We examined whether increases in urinary excretions of these proteins would be in parallel in the same patient.


METHODS
Urinary excretion rates of proteins mentioned above in timed overnight urine samples were evaluated in 61 normoalbuminuric type 2 diabetic patients (group D) aged 40-60 years and in 17 age-matched control subjects (group C).


RESULTS
The excretion rates of these proteins were significantly higher in group D than in group C. These exhibited a strong linear correlation with each other and had a weak correlation with the excretion rate of N-acethylglucosaminidase. The excretion rate of alpha2-macroglobulin with large molecular radii of 88 A was not different between groups C and D, nor did they have any correlations with the excretion rates of the other proteins. Creatinine clearance and blood pressure levels in group D were significantly higher than those in group C.


CONCLUSIONS
In normoalbuminuric diabetic patients, excretion rates of plasma proteins with molecular radii <55 A increased in parallel with each other. In view of our previous finding that urinary excretions of these plasma proteins selectively increased in parallel with enhanced glomerular filtration rate after acute protein loading, the present finding may be explained by renal hemodynamic changes, such as increased intraglomerular hydraulic pressure.
Narita
Takuma
T
Department of Endocrinology, Diabetes and Geriatric Medicine, Akita University School of Medicine, Akita, Japan. narita@med.akita-u.ac.jp
Sasaki
Hiroshi
H
Hosoba
Mihoko
M
Miura
Takeshi
T
Yoshioka
Naomi
N
Morii
Tsukasa
T
Shimotomai
Takashi
T
Koshimura
Jun
J
Fujita
Hiroki
H
Kakei
Masafumi
M
Ito
Seiki
S
D000328:Adult; D000419:Albuminuria; D015992:Body Mass Index; D002570:Ceruloplasmin / Q000652:urine*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology / Q000652:urine*; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007074:Immunoglobulin G / Q000652:urine*; D008875:Middle Aged; D009961:Orosomucoid / Q000652:urine*; D012016:Reference Values; D012044:Regression Analysis; D014168:Transferrin / Q000652:urine*
D002570:Ceruloplasmin; D006442:Glycated Hemoglobin; D007074:Immunoglobulin G; D009961:Orosomucoid; D014168:Transferrin