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Plasma flavin levels of patients receiving long-term hemodialysis
CLINICA CHIMICA ACTA
CCA 4995
PLASlliA
FLAVIN
LEVELS
OF PATIENTS
RECEIVING
LONG-TERM
HEMODIALYSIS
TAKESHI .Departmsd
ITO,
TOY00
NIWA,
EIJI
MATSUI,
NOBUKO
OHISHI*
AND
KUNIO
YAGI*
ofInterzal Medicine, Ogaki .&‘unicipaE HospitaE, Opki and *Institute of Biochemistry,
Faczttty of ~red~czne, ~T~~ve~s~t~of Nagoya, Nagoya, ~~~~an) fReceived
January 20, 1972)
SUMMARY
When hemodialysis was monitored by blood urea nitrogen (RUN) or serum creatinine, the total amounts of flavins in plasma of patients were elevated. This means that the amount of flavins removed through the dialyser was less than that absorbed through the intestine, It was also noticed that the dialysance of flavins was lower than that of urea or creatinine. Accordingly, dietary flavins appear to be enough to replace losses; further supplement of riboflavin is not necessary.
Long-term hemodialysis has been widely accepted as an effective treatment for patients with renal failure. The artificial kidney was primarily designed to remove toxic waste products, but has, at the present time, no mechanism for the reabsorption of many compounds of small molecular weight that could be lost through the dialysis membranes. Since the water-soluble vitamins have molecular sizes within the range of the pore size of the membranes, it was suspected that a supplement of vitamins would be necessary for patients receiving hemodialysis for a long period of time. The plasma levels of vitamins in patients receiving long-term hemodialysis have been extensively investigated1-6, but the necessity for supplements of vitamins was not clearly established. In the present paper, we report the plasma flavin levels of such patients, in order to determine the requirement of vitamin supplementation in the diets of these patients. Our results clearly demonstrate that supplementation is not necessary in patients treated under the conditions reported in the present paper. EXPERIMENTAL
All patients in the present study had chronic renal failure and were being treated with hemodialysis for periods beyond 5 months. They received regular hemodialysis for 8 h at least twice a week, and were otherwise normal. The patients were requested to follow a diet containing 1-2 mg of riboflavin per day, and 1.0 g of protein of high biological value per kg of body weight. The diet contains other vitamins to meet the daily requirement. The amount of sodium chloride taken per day was conClin. Claim. Acta, 39
(1972) 1rzy--1zg
IT0
126
et al.
trolled to be 3-5 g. Diet taken per kg of body weight had ca. 40 cal. The patients did not receive any additional vitamin supplements until the beginning of the experiments. The standard Kiil dialyser and Mini-Kiil dialyser (Western Gear Co.) with a dialysate flow of 500 ml/min were used for hemodialysis. Total heparinization was always carried out. The blood pump was used when blood flow decreased below 150 ml / min. The total amount of flavins in plasma was determined according to Magi’ as modified by Yagi et al.B. The dialysance of flavins was calculated as follows: D
=
{in) ~ (out) x (out)
B.F.
D stands for dialysance, (in) = Aavin concentration in plasma at inlet of the dialyser, (out) = Aavin concentration in plasma at outlet of the dialyser, and B.F., blood flow through the dialyser in ml/min. RESULTS
Plasma
flavin
levels of the patients
receiving
long-term
hemodialysis
The total amounts of flavins of II patients who received long-term hemodialysis are represented in Table I. The total amounts of flavins in the plasma on the patients were significantly higher than those found in normal subjects ($ < 0.02), though a fairly large deviation was observed in the data for the patients. Effect
of hemodialysis
on plasma
javin
level
The above results, which were not in accord with the prediction mentioned in the introductory part of this paper, provoked an examination of the effect of hemodialysis on the plasma Aavin levels of the patients. Table II summarizes the plasma flavin levels of 8 patients who were receiving TABLE
I
Flavin
concentration
I uridl I
Patients
A’o. I
II.2
2.6
36.5 I.0 9.4
I.9 1.5 I .6
5.9 6.9
I.3 I.0
28.7 57.9
1.5 2.8 I.5 I.1 2.1 1.6
3r.7 26.0 102.6
lMean + SD.
28.8 +
Patients
p c
us. normals
Clin. Chirn. Acta,
39 (1972)
28.3
0.02. 125-129
I.7 & 0.5
PLASMA FLAVIN TABLE
IN LONG-TERM HEMODIALYSIS
127
II
EFFECT OF HEMODIALYSIS
ON
PLASMA
FLAVIN
LEVELS
OF
THE
PATIENTS _-__
--
Ftavin concentration (pg/dl)
No.
P~std~a~~ls~~
PWdiUl~SiS -_ 2.8
I 2 3 4
I.2
IT.2
2
94
::
5~9 6.4
Mean f
S.D.
10.2
3.1
6.3 36.9 I.6
7.2 4,3 6.9 +
8.5
15.0
Outlet I.5
II.2
6.0
8.6 36.5 I.0
Inlet
-&
10.8
6.4
9.7 36.5
7.3 31.6
1.1
0.6
9.4 13.5 5.9
7.7 6.3 4.8
11.3 -& 10.2
ii.2 & 9.1
regular hemodialysis. Each procedure for hemodialysis was started at 5.30 a.m. and terminated at 4.30 p.m. Lunch was given to the patients during hemodialysis. When the Aavin levels of pre- and postdialysis were compared, a decrease was found in 5 cases, and an increase or no change in 3 cases, even though the levels at the outlet of the dialyser were always lower than those at the inlet (see Fig. I). The increase in flavin level must be ascribed to the absorption of alimentary flavins during hemodialysis.
To explain the observation that the flavin levels of the patients receiving hemodialyses were not decreased in spite of a considerable removal of flavins through the dialyser, dialysance of flavins was measured in comparison with that of urea or creatinine. The results obtained in 5 patients are represented in Fig. 2. From the figure, it can be seen that dialysance increases with the rate of blood flow, though flavin is cleared more slowly than urea or creatinine, especially when the blood flow is at a rate below zoo ml/min. 120
too
100
120
100
80
100
80 %
60
L
Prediaiysis
60
i’ostdialysis
Fig. x. Plasma flavin levels of the patients. A, Comparison of flavin concentrations pre and post dialysis; B, Comparison of flavin concentrations at the inlet and outlet. Each value postdialysis or at the outlet was expressed in percent of the corresponding value predialysis at the inlet, respectively (n = 8). Clin. Chim. Acta, 39 (1972) 125--Izg
128
IT0 et al.
150 I
200 Blood
300
250
flow (ml/min)
Fig. 2. Dialysance of flavins compared with that of creatinine or urea. (0). &an value of dialysance of flavins; (x ), that cf creatinine; (o), that of urea. Vertical bars indicate standard deviations. n = 5.
E#ect
of admi&stration of jlavin to patients receiving hemodialysis A flavin loading test was performed by injecting flavin adenine dinucleotide (FAD) into 4 patients while they were receiving hemodialysis. As can be seen from Fig. 3, curve II, prolonged elevation of plasma flavin levels was found. When the patients were injected FAD in the intermission period of the hemodialysis, the elevation of plasma flavin levels was more remarkable (see Fig. 3, curve I). In contrast, the plasma flavin levels of the normal subjects were increased transitorily by FAD injection and decreased to the normal level within 120 min after the injection (see Fig. 3, curve III).
Time
(min)
Fig. 3. Time course of plasma flavin levels after loading of FAD. I, of patients (n = 4) in the intermission of hemodialysis; II, of patients (n = 4) receiving hemodialysis; III, of normals (x = 5). Solid circles and vertical bars indicate mean values and standard deviations, respectively, and b denotes those before the loading. Clin. Chim.
Acta,
39 (1972) 125-129
PLASMA FLAVIN
IN LONG-TERM
HEMODIALYSIS
129
DISCUSSION
The important observation in the present study was that the plasma flavin levels of the patients receiving long-term hemodialysis were significantly higher than those of the normals. Neglecting the synthesis of flavins by intestinal micro-organisms and the excretion of flavins in these patients, the observed increase should be explained by the balance between the absorption of alimentary flavins and its removal during hemodialysis. The present experimental data on dialysance of flavins as compared with that of urea or creatinine support this observation. In addition, it was also confirmed that injected flavin remained in the body until it was excreted through the dialyser. Accordingly, the observation that the plasma flavin levels of the patients receiving hemodialysis were not decreased, but elevated, was not suprising. Although in the patients receiving hemodialysis, when BUN or serum creatinine was used as indicator, a high plasma flavin level was observed; such an increase does not seem to indicate toxicity. The increased flavin level emphasizes that there is no need to supplement the diet with flavins. This may also be the case for other water-soluble vitamins. REFERENCES I N. LASKER, A. HARVEY AND H. BAKER, Trans. Amer. Sot. Artif. Internal Organs, g (1963) 51. 2 C. L. HAMPERS, R. STREIFF, D. G. NATHAN, D. SNYDER AND J. P. MERRILL, Neze, Engl. J. Med., 27’5 (1967) 551. 3 V. M. WHITEHEAD, C. H. COMTY, G. A. POSES AED M. KAYE, New Engl. J. Med., 279 (1968) 970. 4 L. H. SEVITT AND A. V. HOFFBRAND, Brit. Med. J., ii (1969) 18. 5 J. G. MCKENZIE, J. E. FORD, N. HARDING, A. H. WATERS AND W. R. CATTEL, Proc. Ewop. Dialysis Transplant. Assoc., 5 (1968) 172. 6 J. F. SULLIVAN AND A. B. EISENSTEI~, Amer. J. Clin. N&r., 23 (1970) 1339. 7 K. YAGI, Methods ofBiochemical Analysis, Vol. X, Inter-science, New York, 1962, p. 319. 8 K. YAGI, S. KIKUCHI AND T. KARIYA, Vitamirzs, 8 (1955) 450. C&n. Chim.
Acta,
3g (1972)
I25--I29
CCA 4995
PLASlliA
FLAVIN
LEVELS
OF PATIENTS
RECEIVING
LONG-TERM
HEMODIALYSIS
TAKESHI .Departmsd
ITO,
TOY00
NIWA,
EIJI
MATSUI,
NOBUKO
OHISHI*
AND
KUNIO
YAGI*
ofInterzal Medicine, Ogaki .&‘unicipaE HospitaE, Opki and *Institute of Biochemistry,
Faczttty of ~red~czne, ~T~~ve~s~t~of Nagoya, Nagoya, ~~~~an) fReceived
January 20, 1972)
SUMMARY
When hemodialysis was monitored by blood urea nitrogen (RUN) or serum creatinine, the total amounts of flavins in plasma of patients were elevated. This means that the amount of flavins removed through the dialyser was less than that absorbed through the intestine, It was also noticed that the dialysance of flavins was lower than that of urea or creatinine. Accordingly, dietary flavins appear to be enough to replace losses; further supplement of riboflavin is not necessary.
Long-term hemodialysis has been widely accepted as an effective treatment for patients with renal failure. The artificial kidney was primarily designed to remove toxic waste products, but has, at the present time, no mechanism for the reabsorption of many compounds of small molecular weight that could be lost through the dialysis membranes. Since the water-soluble vitamins have molecular sizes within the range of the pore size of the membranes, it was suspected that a supplement of vitamins would be necessary for patients receiving hemodialysis for a long period of time. The plasma levels of vitamins in patients receiving long-term hemodialysis have been extensively investigated1-6, but the necessity for supplements of vitamins was not clearly established. In the present paper, we report the plasma flavin levels of such patients, in order to determine the requirement of vitamin supplementation in the diets of these patients. Our results clearly demonstrate that supplementation is not necessary in patients treated under the conditions reported in the present paper. EXPERIMENTAL
All patients in the present study had chronic renal failure and were being treated with hemodialysis for periods beyond 5 months. They received regular hemodialysis for 8 h at least twice a week, and were otherwise normal. The patients were requested to follow a diet containing 1-2 mg of riboflavin per day, and 1.0 g of protein of high biological value per kg of body weight. The diet contains other vitamins to meet the daily requirement. The amount of sodium chloride taken per day was conClin. Claim. Acta, 39
(1972) 1rzy--1zg
IT0
126
et al.
trolled to be 3-5 g. Diet taken per kg of body weight had ca. 40 cal. The patients did not receive any additional vitamin supplements until the beginning of the experiments. The standard Kiil dialyser and Mini-Kiil dialyser (Western Gear Co.) with a dialysate flow of 500 ml/min were used for hemodialysis. Total heparinization was always carried out. The blood pump was used when blood flow decreased below 150 ml / min. The total amount of flavins in plasma was determined according to Magi’ as modified by Yagi et al.B. The dialysance of flavins was calculated as follows: D
=
{in) ~ (out) x (out)
B.F.
D stands for dialysance, (in) = Aavin concentration in plasma at inlet of the dialyser, (out) = Aavin concentration in plasma at outlet of the dialyser, and B.F., blood flow through the dialyser in ml/min. RESULTS
Plasma
flavin
levels of the patients
receiving
long-term
hemodialysis
The total amounts of flavins of II patients who received long-term hemodialysis are represented in Table I. The total amounts of flavins in the plasma on the patients were significantly higher than those found in normal subjects ($ < 0.02), though a fairly large deviation was observed in the data for the patients. Effect
of hemodialysis
on plasma
javin
level
The above results, which were not in accord with the prediction mentioned in the introductory part of this paper, provoked an examination of the effect of hemodialysis on the plasma Aavin levels of the patients. Table II summarizes the plasma flavin levels of 8 patients who were receiving TABLE
I
Flavin
concentration
I uridl I
Patients
A’o. I
II.2
2.6
36.5 I.0 9.4
I.9 1.5 I .6
5.9 6.9
I.3 I.0
28.7 57.9
1.5 2.8 I.5 I.1 2.1 1.6
3r.7 26.0 102.6
lMean + SD.
28.8 +
Patients
p c
us. normals
Clin. Chirn. Acta,
39 (1972)
28.3
0.02. 125-129
I.7 & 0.5
PLASMA FLAVIN TABLE
IN LONG-TERM HEMODIALYSIS
127
II
EFFECT OF HEMODIALYSIS
ON
PLASMA
FLAVIN
LEVELS
OF
THE
PATIENTS _-__
--
Ftavin concentration (pg/dl)
No.
P~std~a~~ls~~
PWdiUl~SiS -_ 2.8
I 2 3 4
I.2
IT.2
2
94
::
5~9 6.4
Mean f
S.D.
10.2
3.1
6.3 36.9 I.6
7.2 4,3 6.9 +
8.5
15.0
Outlet I.5
II.2
6.0
8.6 36.5 I.0
Inlet
-&
10.8
6.4
9.7 36.5
7.3 31.6
1.1
0.6
9.4 13.5 5.9
7.7 6.3 4.8
11.3 -& 10.2
ii.2 & 9.1
regular hemodialysis. Each procedure for hemodialysis was started at 5.30 a.m. and terminated at 4.30 p.m. Lunch was given to the patients during hemodialysis. When the Aavin levels of pre- and postdialysis were compared, a decrease was found in 5 cases, and an increase or no change in 3 cases, even though the levels at the outlet of the dialyser were always lower than those at the inlet (see Fig. I). The increase in flavin level must be ascribed to the absorption of alimentary flavins during hemodialysis.
To explain the observation that the flavin levels of the patients receiving hemodialyses were not decreased in spite of a considerable removal of flavins through the dialyser, dialysance of flavins was measured in comparison with that of urea or creatinine. The results obtained in 5 patients are represented in Fig. 2. From the figure, it can be seen that dialysance increases with the rate of blood flow, though flavin is cleared more slowly than urea or creatinine, especially when the blood flow is at a rate below zoo ml/min. 120
too
100
120
100
80
100
80 %
60
L
Prediaiysis
60
i’ostdialysis
Fig. x. Plasma flavin levels of the patients. A, Comparison of flavin concentrations pre and post dialysis; B, Comparison of flavin concentrations at the inlet and outlet. Each value postdialysis or at the outlet was expressed in percent of the corresponding value predialysis at the inlet, respectively (n = 8). Clin. Chim. Acta, 39 (1972) 125--Izg
128
IT0 et al.
150 I
200 Blood
300
250
flow (ml/min)
Fig. 2. Dialysance of flavins compared with that of creatinine or urea. (0). &an value of dialysance of flavins; (x ), that cf creatinine; (o), that of urea. Vertical bars indicate standard deviations. n = 5.
E#ect
of admi&stration of jlavin to patients receiving hemodialysis A flavin loading test was performed by injecting flavin adenine dinucleotide (FAD) into 4 patients while they were receiving hemodialysis. As can be seen from Fig. 3, curve II, prolonged elevation of plasma flavin levels was found. When the patients were injected FAD in the intermission period of the hemodialysis, the elevation of plasma flavin levels was more remarkable (see Fig. 3, curve I). In contrast, the plasma flavin levels of the normal subjects were increased transitorily by FAD injection and decreased to the normal level within 120 min after the injection (see Fig. 3, curve III).
Time
(min)
Fig. 3. Time course of plasma flavin levels after loading of FAD. I, of patients (n = 4) in the intermission of hemodialysis; II, of patients (n = 4) receiving hemodialysis; III, of normals (x = 5). Solid circles and vertical bars indicate mean values and standard deviations, respectively, and b denotes those before the loading. Clin. Chim.
Acta,
39 (1972) 125-129
PLASMA FLAVIN
IN LONG-TERM
HEMODIALYSIS
129
DISCUSSION
The important observation in the present study was that the plasma flavin levels of the patients receiving long-term hemodialysis were significantly higher than those of the normals. Neglecting the synthesis of flavins by intestinal micro-organisms and the excretion of flavins in these patients, the observed increase should be explained by the balance between the absorption of alimentary flavins and its removal during hemodialysis. The present experimental data on dialysance of flavins as compared with that of urea or creatinine support this observation. In addition, it was also confirmed that injected flavin remained in the body until it was excreted through the dialyser. Accordingly, the observation that the plasma flavin levels of the patients receiving hemodialysis were not decreased, but elevated, was not suprising. Although in the patients receiving hemodialysis, when BUN or serum creatinine was used as indicator, a high plasma flavin level was observed; such an increase does not seem to indicate toxicity. The increased flavin level emphasizes that there is no need to supplement the diet with flavins. This may also be the case for other water-soluble vitamins. REFERENCES I N. LASKER, A. HARVEY AND H. BAKER, Trans. Amer. Sot. Artif. Internal Organs, g (1963) 51. 2 C. L. HAMPERS, R. STREIFF, D. G. NATHAN, D. SNYDER AND J. P. MERRILL, Neze, Engl. J. Med., 27’5 (1967) 551. 3 V. M. WHITEHEAD, C. H. COMTY, G. A. POSES AED M. KAYE, New Engl. J. Med., 279 (1968) 970. 4 L. H. SEVITT AND A. V. HOFFBRAND, Brit. Med. J., ii (1969) 18. 5 J. G. MCKENZIE, J. E. FORD, N. HARDING, A. H. WATERS AND W. R. CATTEL, Proc. Ewop. Dialysis Transplant. Assoc., 5 (1968) 172. 6 J. F. SULLIVAN AND A. B. EISENSTEI~, Amer. J. Clin. N&r., 23 (1970) 1339. 7 K. YAGI, Methods ofBiochemical Analysis, Vol. X, Inter-science, New York, 1962, p. 319. 8 K. YAGI, S. KIKUCHI AND T. KARIYA, Vitamirzs, 8 (1955) 450. C&n. Chim.
Acta,
3g (1972)
I25--I29