Regular Contributions
Effects of Short-Term Glycemic
Control, Low Protein Diet and Administration of Enalapril on Renal
Hemodynamics and Protein Permselectivity in Type 2 Diabetic Patients
with Microalbuminuria
- TAKUMA NARITA,
JUN KOSHIMURA,
KATSUNORI SUZUKI,
MASAHIKO MURATA,
HIROYUKI MEGURO,
HIROKI FUJITA, HIROJI
KITAZATO and SEIKI
ITO
- Division of Geriatric Medicine, Akita
University Hospital, Akita 010-8543
To determine whether each of
glycemic control (GC), low protein diet (LPD) or administration of
angiotensin converting enzyme inhibitor (ACEI) has beneficial effects
on diabetic nephropathy through the different mechanisms, changes in
charge and size selectivity of glomerulus and renal hemodynamics were
analyzed in microalbuminuric type 2 diabetic patients after additive
combination therapy (first period: GC only, second period: GC+LPD,
third period: GC+LPD+ACEI). To detect improvement of the impairments
of glomerular charge selectivity and size selectivity, changes in the
ratio of the renal clearance of two plasma proteins with similar
molecular radii and different isoelectric points (pIs) (ceruloplasmin
and IgG: CRL/IgG) and changes in the ratio of the renal clearance of
two plasma proteins with similar pIs and different molecular radii
(a2-macroglobulin and albumin:
a2/Alb) were examined before and
after each therapy. Creatinine clearance decreased significantly in
the first and third periods although slight but not significant
decrease was detected in the second period. Filtration fraction was
significantly decreased only in the third period. Although renal
clearances of Alb, IgG and CRL were decreased in periods of all three
therapies, that of a2-macroglobulin
with a large molecular radius was decreased significantly only after
the third therapy. Neither CRL/IgG nor a2/Alb changed during these three therapies.
These findings suggest that each of three short-term therapies
consisting of GC, GC+LPD and GC+LPD+ACEI, reduced proteinuria in
microalbuminuric type 2 diabetic patients not through the improvement
of renal size and charge selectivities, but through improvement of
renal hemodynamics.
Key words--- early diabetic nephropathy; renal
hemodynamics; decreased proteinuria; charge selectivity; size
selectivity
© 1999 Tohoku University Medical Press
Tohoku J. Exp. Med., 1999,
189,117-133
Address for reprints: Takuma Narita, Division of Geriatric
Medicine, Akita University Hospital, 1-1-1 Hondo, Akita 010-8543,
Japan.
e-mail: narita@med.akita-u.ac.jp
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