Diabetes Care, Vol 20, Issue 6 1019-1026, Copyright © 1997 by American Diabetes Association
Transcapillary escape rate of albumin in type II diabetic patients. The relationship with microalbuminuria and hypertension
M Nannipieri, G Penno, L Rizzo, L Pucci, S Bandinelli, P Mattei, S Taddei, A Salvetti and R Navalesi
Cattedra di Malattie Metaboliche e del Ricambio, Istituto di Clinica Media II, University of Pisa, Italy.
OBJECTIVE: To study why in type II diabetes, microalbuminuria, a marker of
generalized vascular dysfunction, and hypertension have been linked with
both renal and cardiovascular organ damage. RESEARCH DESIGN AND METHODS: To
investigate the effect of moderately elevated blood pressure on vascular
damage, the transcapillary escape rate of albumin (TERalb) was measured by
intravenous injection of purified 125I-human serum albumin in 9 healthy
control subjects (group 1), 9 nondiabetic hypertensive subjects (group 2),
and 73 nonobese type II diabetic patients stratified as follows: group 3:
17 normoalbuminuric-normotensive subjects; group 4: 22
normoalbuminuric-hypertensive subjects (systolic blood pressure [sBP] >
or = 140 mmHg or diastolic blood pressure [dBP] > or = mmHg or both);
group 5: 16 normotensive subjects with microalbuminuria (albumin excretion
rate [AER]: 20-200 micrograms/min); and group 6: 18
microalbuminuric-hypertensive subjects. RESULTS: Groups 3-6 had similar
age, sex, duration of diabetes (group 3: 7.8 +/- 5.5; group 4: 9.7 +/- 8.7;
group 5: 12.1 +/- 8.1; and group 6: 10.7 +/- 8.3 years), BMI, HbA1c (7.8
+/- 1.1, 7.5 +/- 1.5, 8.7 +/- 1.5, and 7.7 +/- 1.1%, respectively), blood
glucose, and lipid profile. Systolic and diastolic blood pressure did not
differ in the three hypertensive group (group 2: 154 +/- 3/99 +/- 6; group
4: 149 +/- 13/95 +/- 6; group 6: 154 +/- 15/91 +/- 9 mmHg) and were
significantly lower (P < 0.001) in group 3 (126 +/- 12/76 +/- 7), group
5 (128 +/- 11/77 +/- 5), and healthy control subjects (group 1: 133 +/-
7/81 +/- 4). TERalb was similar in control subjects (5.77 +/- 1.06%/h) and
in normoalbuminuric-normotensive subjects (5.81 +/- 1.51%/h) but
significantly higher (P < 0.0001) in microalbuminuric subjects with or
without hypertension (9.11 +/- 1.65 and 8.60 +/- 1.50%/h, respectively) as
well as in normoalbuminuric diabetic patients with hypertension (8.10 +/-
2.27%/h) and in essential hypertensive subjects (8.12 +/- 1.68%/h).
CONCLUSIONS: By stepwise regression, TERalb was related (step 1) to log-AER
(r = 0.30) or to the presence of microalbuminuria (r = 0.36) and (step 2)
to dBP (multiple r = 0.40) or to the presence of hypertension (multiple r =
0.51) in the whole diabetic cohort (groups 3-6). TERalb was related to dBP
(r = 0.47) or to the presence of hypertension (r = 0.56) only in
normoalbuminuric diabetic patients (groups 3 and 4) and to log-AER (r =
0.56) or the presence of microalbuminuria (r = 0.68) only in normotensive
patients (groups 3 and 5). In type II diabetic patients, TERalb was
elevated in subjects with increased albuminuria, irrespective of blood
pressure levels, but also was independently related to the presence of
mild-to-moderate systemic hypertension.