Urinary Albumin Excretion during Exercise in Juvenile Diabetes A Provocation Test for Early Abnormalities
Scand J Clin Lab Invest Downloaded from informahealthcare.com by McMaster University on 12/26/14 For personal use only.
C. E. MOGENSEN & E. VITTINGHUS Second University Clinic of Internal Medicine, Kommunehospitalet, Aarhus, Denmark
Mogensen, C. E. & Vittinghus, E. Urinary Albumin Excretion during Exercise in Juvenile Diabetes. A Provocation Test for Early Abnormalities. Scand. J . d i n . Lab. Invest. 35, 295-300, 1975. Urinary albumin excretion during exercise was measured with a radioimmunological method in a group of 1 3 young male diabetic patients and in a comparable control group. The duration of diabetes was 2-18 years; they had no proteinuria (AlbustixB) and no other signs of renal disease. There was no difference in the basal albumin excretion. In the diabetics the average albumin excretion was doubled during exercise at 600 kpmlmin for 20 min, from 9.1 pglmin to 18.7 pg/min (P < 0.005). N o significant change was seen in the controls. These results strongly suggest that abnormal glomerular filter properties are present in patients with relatively short duration of diabetes that is, in patients who are known to have thickened glomerular basement membrane. The exercise provocation test may be useful in other fields of renal pathophysiology. Key-words: Albumin; diabetes mellitus; exercise; glomerulus; kidney function test; proteinuria; radioimmunoassay C. E. Mogensen, M . D . , Medicinsk afdeling M , Komniiinehospitalet, 8000 Aarhus C . Denmark
I n a n earlier study it was shown that young diabetic patients without proteinuria as measured by AlbustixO had normal urinary albumin excretion when measured quantitatively with the radioimmunological technique. Urine samples were collected when the patients and the normals were u p and about (10). I t has been established by the work of Osterby (15, 16) that a n increased thickness of the peripheral glomerular basement membrane can be demonstrated already after a duration of diabetes of 1-2 years. Since this morphological abnormality may cause alterations in the filtering properties of the glomerulus, it was decided to extend the study of urinary albumin excre-
tion by introducing a provocation test. Exercise seems a reasonable choice since this would be a physiological stimulus and the exercise proteinuria is well established in normal subjects (2, 3, 19). T h e idea was that a certain workload would not cause increase in albumin excretion in normal subjects but possibly in diabetic patients with early glomerular abnormalities. T h e exercise test has been used by Karlefors (7) to demonstrate hemodynamic abnormalities in diabetic subjects related to the duration of the disease, and Prange Hansen (5) has found pronounced abnormalities in growth hormone secretion in juvenile diabetes during exercise.
296
C . E. Mogerisen & E . Vittinghus
Table I. Clinical data and effect of exercise in diabetic patients Patients
Scand J Clin Lab Invest Downloaded from informahealthcare.com by McMaster University on 12/26/14 For personal use only.
Case no. 1 2 3 4 5 6 7 8 9
10 11 12 13
Urinary albumin excretion (crglmin)
Duration of RetiSerum Age diabetes nopathy glucose (years) (years) (stage) (mg/100ml) Rest 26 22 29 38 27 21 26 23 23
Cases 1-9 Mean 26 S.D.
Clinical Data
5.2 24 22 30 24
2 2 2 2 3 4 5 5 7
0 0 0 0 0 0 0 0 0
3.6 1.8 12 14 15 18
Cases 10-13 Mean 25 S.D. 3.5
15 2.5
Cases 1-13 Mean 26 S.D. 4.6
7.0 5.7
I1 I I I
Exercise 600
450
Heart rate
-
Exercise (kpm/min)
Increase A450
A600
Rest
450
600
19.8 9.7
62 52 60 64 72 56 60
108 104 112
50
120 98 116 120 100
140 124 144 120 136 128 128 150 126
60 6.7
109 8.3
133 10.1
125 87 88 276 117 128 202 229 143
5.7 7.9 5.5 10.2 7.7 7.3 14.8 5.2 7.8
8.8 8.6 8.1 10.9 8.0 6.6 16.6 4.3 10.0
25.5 17.6 11.3 19.8 9.2 16.5 20.7 11.3 16.2
3.1 0.7 2.6 0.7 0.3 -0.7 -0.9 2.2
9.6 1.5 9.2 5.9 6.1 8.4
155 66
8.0 3.0
9.1 3.4
16.5 5.2
1.1 1.4
5.0
52 188 224 293
23.4 9.3 6.1 7.7
30.7 8.4 5.8 5.5
43.5 14.6 14.1 23.1
7.3 -0.9 -0.3 -2.2
20.1 5.3 8.0 15.4
80 68 64 76
100 128 100 112
132 150 120 132
189 101.3
11.6 8.0
12.6 12.1
23.8 13.8
1.0 4.3
12.2 6.8
72 7.3
110 13.3
134 13.3
9.1
10.2 6.9
18.7 8.8
1.1 2.4
9.6 5.6
64 8.8
109 9.5
133 10.3
166 76
5.0
MATERIAL AND METHODS
A radioimmunoassay described in detail earlier (8) was used for measuring urinary albumin. The subjects were examined in the morning. To promote urinary output the subjects were given 250 ml of tap water to drink every 20 min, starting 1% hr before the experiment. During that period they were at rest, the last half hour in the supine position. After voiding, the experiment was started with the subjects sitting for two consecutive periods of 20 min on a bicycle ergometer, followed by two 20-min exercise periods, also in the sitting position. The exercise load was 450 kpmlmin, followed by a load of 600 k p m h i n . Heart rate was counted three times in each period. After voiding, 7 ml urine was stored in plastic tubes, to which 10 pl of 20% bovine albumin (Ortho
1.8
5.8
8.4
64
104
Diagnostics) was added to prevent adsorption. The samples were stored deep-frozen until analysis. Some subjects were examined in the fasting state and some after a light morning meal, in the latter case the diabetic subjects received their usual insulin dose in the morning. When they were fasting, they received insulin after the experiment. Plasma glucose was in the diabetics measured before the experiment using a toluidine method. If they were not fasting on the day of the experiment, a fasting value measured a few days before was used (Table I). Thirteen diabetics without proteinuria according to Albustixm and with a duration of diabetes of less than 20 years were examined. Nine patients had no signs of retinopathy, and their mean duration of diabetes was 3.6 years 1.8 S.D. (range, 2-7 years). Four patients
*
Albumin Excretion during Exercise
297
Table 11. Effect of exercise in normal subjects Subjects
Urinary albumin excretion (pg/min)
Scand J Clin Lab Invest Downloaded from informahealthcare.com by McMaster University on 12/26/14 For personal use only.
Exercise (kpm/min)
Heart rate
Increase
Exercise (kpm/rnin)
Case no.
Age (years)
Rest
450
600
A450
A600
Rest
450
600
14 15 16 17 18 19 20 21 22 23 24 25
24 29 29 24 30 24 34 24 23 24 23 31
27.8 7.9 6.6 3.3 7.7 22.8 3.8 4.5 4.3 5.2 5.4 5.0
25.2 5.5 8.2 5.8 4.2 15.0 4.4 6.5 8.8 6.9 6.5 4.2
22.8 7.4 13.5 5.6 8.5 20.5 5.0 10.5 6.0 5.6 16.6 4.5
-2.6 -2.4 I .6 2.5 -3.5 -7.8 0.6 2.0 4.5 1.7 1.1 -0.8
-5.0 4.5 6.9 2.3 0.8 -2.3 1.2 6.0 1.7 0.4 11.2
68 80 70 72
112 108 118 108 108 116 88 100 106 116 108
136 134 144 130 124 128 120 132 120 126 136 120
Mean S.D.
27 3.8
8.7 8.0
8.4 6.0
10.5 6.4
4.3 3.3
1.9 4.4
108 8.1
129 7.6
with a mean duration of 15 years f 2.5 S.D. (range, 12-18 years) had retinopathy grade I and I1 according to Jensen & Lundbaek (6). Twelve normal subjects (medical students and doctors) served as control subjects. Pertinent
64 70 52 62 60 60 68 68
4.5
104
66 7.2
clinical data are shown in Table I and I1 along with results. The mean age of the diabetic and the normal subjects was 26 years f 4.6 S.D. and 27 years 3.8 S.D., respectively. Since the results were not normally distributed, the
*
Table 111 A. Mean urinary albumin excretion (Ng/min) in normal and diabetic subjects Exercise (600 kpm/min)
Level of
Subjects
Rest
Absolute values
Increase (A)
12 normals
8.7
10.5
+1.9
N.S.
13 diabetics (2-20 years’ duration)
9.1
18.7
+9.6
P
Scand J Clin Lab Invest Downloaded from informahealthcare.com by McMaster University on 12/26/14 For personal use only.
C. E. MOGENSEN & E. VITTINGHUS Second University Clinic of Internal Medicine, Kommunehospitalet, Aarhus, Denmark
Mogensen, C. E. & Vittinghus, E. Urinary Albumin Excretion during Exercise in Juvenile Diabetes. A Provocation Test for Early Abnormalities. Scand. J . d i n . Lab. Invest. 35, 295-300, 1975. Urinary albumin excretion during exercise was measured with a radioimmunological method in a group of 1 3 young male diabetic patients and in a comparable control group. The duration of diabetes was 2-18 years; they had no proteinuria (AlbustixB) and no other signs of renal disease. There was no difference in the basal albumin excretion. In the diabetics the average albumin excretion was doubled during exercise at 600 kpmlmin for 20 min, from 9.1 pglmin to 18.7 pg/min (P < 0.005). N o significant change was seen in the controls. These results strongly suggest that abnormal glomerular filter properties are present in patients with relatively short duration of diabetes that is, in patients who are known to have thickened glomerular basement membrane. The exercise provocation test may be useful in other fields of renal pathophysiology. Key-words: Albumin; diabetes mellitus; exercise; glomerulus; kidney function test; proteinuria; radioimmunoassay C. E. Mogensen, M . D . , Medicinsk afdeling M , Komniiinehospitalet, 8000 Aarhus C . Denmark
I n a n earlier study it was shown that young diabetic patients without proteinuria as measured by AlbustixO had normal urinary albumin excretion when measured quantitatively with the radioimmunological technique. Urine samples were collected when the patients and the normals were u p and about (10). I t has been established by the work of Osterby (15, 16) that a n increased thickness of the peripheral glomerular basement membrane can be demonstrated already after a duration of diabetes of 1-2 years. Since this morphological abnormality may cause alterations in the filtering properties of the glomerulus, it was decided to extend the study of urinary albumin excre-
tion by introducing a provocation test. Exercise seems a reasonable choice since this would be a physiological stimulus and the exercise proteinuria is well established in normal subjects (2, 3, 19). T h e idea was that a certain workload would not cause increase in albumin excretion in normal subjects but possibly in diabetic patients with early glomerular abnormalities. T h e exercise test has been used by Karlefors (7) to demonstrate hemodynamic abnormalities in diabetic subjects related to the duration of the disease, and Prange Hansen (5) has found pronounced abnormalities in growth hormone secretion in juvenile diabetes during exercise.
296
C . E. Mogerisen & E . Vittinghus
Table I. Clinical data and effect of exercise in diabetic patients Patients
Scand J Clin Lab Invest Downloaded from informahealthcare.com by McMaster University on 12/26/14 For personal use only.
Case no. 1 2 3 4 5 6 7 8 9
10 11 12 13
Urinary albumin excretion (crglmin)
Duration of RetiSerum Age diabetes nopathy glucose (years) (years) (stage) (mg/100ml) Rest 26 22 29 38 27 21 26 23 23
Cases 1-9 Mean 26 S.D.
Clinical Data
5.2 24 22 30 24
2 2 2 2 3 4 5 5 7
0 0 0 0 0 0 0 0 0
3.6 1.8 12 14 15 18
Cases 10-13 Mean 25 S.D. 3.5
15 2.5
Cases 1-13 Mean 26 S.D. 4.6
7.0 5.7
I1 I I I
Exercise 600
450
Heart rate
-
Exercise (kpm/min)
Increase A450
A600
Rest
450
600
19.8 9.7
62 52 60 64 72 56 60
108 104 112
50
120 98 116 120 100
140 124 144 120 136 128 128 150 126
60 6.7
109 8.3
133 10.1
125 87 88 276 117 128 202 229 143
5.7 7.9 5.5 10.2 7.7 7.3 14.8 5.2 7.8
8.8 8.6 8.1 10.9 8.0 6.6 16.6 4.3 10.0
25.5 17.6 11.3 19.8 9.2 16.5 20.7 11.3 16.2
3.1 0.7 2.6 0.7 0.3 -0.7 -0.9 2.2
9.6 1.5 9.2 5.9 6.1 8.4
155 66
8.0 3.0
9.1 3.4
16.5 5.2
1.1 1.4
5.0
52 188 224 293
23.4 9.3 6.1 7.7
30.7 8.4 5.8 5.5
43.5 14.6 14.1 23.1
7.3 -0.9 -0.3 -2.2
20.1 5.3 8.0 15.4
80 68 64 76
100 128 100 112
132 150 120 132
189 101.3
11.6 8.0
12.6 12.1
23.8 13.8
1.0 4.3
12.2 6.8
72 7.3
110 13.3
134 13.3
9.1
10.2 6.9
18.7 8.8
1.1 2.4
9.6 5.6
64 8.8
109 9.5
133 10.3
166 76
5.0
MATERIAL AND METHODS
A radioimmunoassay described in detail earlier (8) was used for measuring urinary albumin. The subjects were examined in the morning. To promote urinary output the subjects were given 250 ml of tap water to drink every 20 min, starting 1% hr before the experiment. During that period they were at rest, the last half hour in the supine position. After voiding, the experiment was started with the subjects sitting for two consecutive periods of 20 min on a bicycle ergometer, followed by two 20-min exercise periods, also in the sitting position. The exercise load was 450 kpmlmin, followed by a load of 600 k p m h i n . Heart rate was counted three times in each period. After voiding, 7 ml urine was stored in plastic tubes, to which 10 pl of 20% bovine albumin (Ortho
1.8
5.8
8.4
64
104
Diagnostics) was added to prevent adsorption. The samples were stored deep-frozen until analysis. Some subjects were examined in the fasting state and some after a light morning meal, in the latter case the diabetic subjects received their usual insulin dose in the morning. When they were fasting, they received insulin after the experiment. Plasma glucose was in the diabetics measured before the experiment using a toluidine method. If they were not fasting on the day of the experiment, a fasting value measured a few days before was used (Table I). Thirteen diabetics without proteinuria according to Albustixm and with a duration of diabetes of less than 20 years were examined. Nine patients had no signs of retinopathy, and their mean duration of diabetes was 3.6 years 1.8 S.D. (range, 2-7 years). Four patients
*
Albumin Excretion during Exercise
297
Table 11. Effect of exercise in normal subjects Subjects
Urinary albumin excretion (pg/min)
Scand J Clin Lab Invest Downloaded from informahealthcare.com by McMaster University on 12/26/14 For personal use only.
Exercise (kpm/min)
Heart rate
Increase
Exercise (kpm/rnin)
Case no.
Age (years)
Rest
450
600
A450
A600
Rest
450
600
14 15 16 17 18 19 20 21 22 23 24 25
24 29 29 24 30 24 34 24 23 24 23 31
27.8 7.9 6.6 3.3 7.7 22.8 3.8 4.5 4.3 5.2 5.4 5.0
25.2 5.5 8.2 5.8 4.2 15.0 4.4 6.5 8.8 6.9 6.5 4.2
22.8 7.4 13.5 5.6 8.5 20.5 5.0 10.5 6.0 5.6 16.6 4.5
-2.6 -2.4 I .6 2.5 -3.5 -7.8 0.6 2.0 4.5 1.7 1.1 -0.8
-5.0 4.5 6.9 2.3 0.8 -2.3 1.2 6.0 1.7 0.4 11.2
68 80 70 72
112 108 118 108 108 116 88 100 106 116 108
136 134 144 130 124 128 120 132 120 126 136 120
Mean S.D.
27 3.8
8.7 8.0
8.4 6.0
10.5 6.4
4.3 3.3
1.9 4.4
108 8.1
129 7.6
with a mean duration of 15 years f 2.5 S.D. (range, 12-18 years) had retinopathy grade I and I1 according to Jensen & Lundbaek (6). Twelve normal subjects (medical students and doctors) served as control subjects. Pertinent
64 70 52 62 60 60 68 68
4.5
104
66 7.2
clinical data are shown in Table I and I1 along with results. The mean age of the diabetic and the normal subjects was 26 years f 4.6 S.D. and 27 years 3.8 S.D., respectively. Since the results were not normally distributed, the
*
Table 111 A. Mean urinary albumin excretion (Ng/min) in normal and diabetic subjects Exercise (600 kpm/min)
Level of
Subjects
Rest
Absolute values
Increase (A)
12 normals
8.7
10.5
+1.9
N.S.
13 diabetics (2-20 years’ duration)
9.1
18.7
+9.6
P
