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Serum angiotensin converting enzyme activity in cigarette smokers
69
Clinica Chimicu Actu, 154 (1986) 69-72 Elsevier
CCA 03361
Short communication
Serum angiotensin converting enzyme activity in cigarette smokers Nuha A.A. Haboubi n Department
a, A.H.C. Bignell a and N.Y. Haboubi
b
of Clinical Chemisiry, Dudley Road Hospital, Birmingham B18 7QH and’ East Birmingham Hospital, Bordesley Green East, Birmingham B9 5ST (UK) (Received
April 9th, 1985; revision July 9th. 1985)
Key words: Kininase II; Smoking;
Lung diseases, obstructive
Summary
Low activity of angiotensin converting enzyme (ACE) has been reported in patients with smoking related diseases, such as chronic bronchitis, emphysaema and carcinoma of the lung (11 but this has not been reported in healthy, chronic smokers. Serum ACE was measured in 40 healthy cigarette smokers and in 42 healthy non-smokers. The mean value was significantly lower in the smokers. Hence a patient’s smoking habits should be taken into consideration when assessing the significance of his serum ACE levels.
Introduction
Angiotensin converting enzyme (ACE) is localised on the luminal surface of the vascular endothelial cells of the lung [2] and is produced mainly in the lung [3,4]. Several reports have suggested that alteration in angiotensin conversion occurs in pulmonary disorders or when abnormalities in pulmonary function are experimentally produced [5,6]. This raises the possibility that the reduction in converting enzyme activity may be related to a loss of vascular endothelial surface area [7]. Depressed converting enzyme activity has been reported in a variety of pulmonary diseases including bronchial asthma, cystic fibrosis, chronic bronchitis, emphysaema and bronchial carcinoma [ 1,8]. While acute hypoxia was found to inhibit ACE in both dogs [9] and humans [lo], acute exposure to cigarette smoking increases the conversion of angiotensin I and angiotensin II in rat isolated lung [ll] and in humans [12]. The chronic effect of cigarette smoking on the ACE has not been described. The aim of this study was to document ACE activity in chronic cigarette smokers. 0009-8981/86/$03.50
0 1986 Elsevier Science Publishers
B.V. (Biomedical
Division)
Patients and methods
Volunteers from the hospital medical, nursing, clerical, auxiliary and laboratory staff were studied. There were 40 smokers and 42 non-smokers. The former group had smoked over 15 middle tar cigarettes daily for at least 10 yr; none of the latter had ever smoked. None of the subjects had a history of hypertension, diabetes, lung or thyroid disease. The smokers were 20 males and 20 females. Their mean age was 33.05 yr (range 27-45). The non-smokers were 22 males and 20 females. Their mean age was 32.19 yr (range 25-45). Blood samples were taken from the smokers at least 1 h after smoking to eliminate any acute effect of smoking on the activity of the enzyme [12]. Serum ACE acti&ies were determined fluorimetrically according to the method of Friedland and Silverstein using hippuryl-L-histidyl-L-leucine as substrate [13] (Sigma Chemical Co., Dorset, UK). Serum ACE was measured in duplicate. Results are reported as pmol/l (pm01 of hippuric acid liberated/mm per 1 of serum). The within-batch coefficient of variation (CV) for 200 assays was 6% and between batch for 20 assays in duplicate was 8.5% (mean value 35). 60
. .. ..
55
--a..
50
.‘. ..
45
&O
35
.. . A
30
.Y .
20
15
10
.. . . . SMOKERS GROUP
NON-SMOKERS GROUP
Fig. 1. Scattergram of serum ACE activity in healthy smokers and healthy non-smokers. The long horizontal bars represent the values of the mean and the short ones represent 1 SD in each group.
71
Results The mean value of serum ACE activity (Fig. 1) for the smokers was 31.1 pmol/l 8.14). For the non-smokers the mean value was 40.8 pmol/l (SD 10.78). The t test of the two groups gave a value of 4.6112 for which p < 0.001. All of these results lay within our normal laboratory reference range (8-59 pmol/l), which was obtained from healthy volunteers without taking into consideration their smoking habits. There was no significant difference in the ACE activities between the male and female subjects.
(SD
Discussion The two groups which we have studied were all healthy personnel from the hospital staff. Smoking is known to have numerous adverse effects on lung tissue some of which are well-documented. However, the direct effect of cigarette smoking on the pulmonary capillary bed is not clear. We have shown that serum ACE activities are reduced in chronic smokers. The mechanism of this reduction may be that smoking either destroys the endothelial cells which release ACE into the pulmonary circulation or inhibit the release of the enzyme. These results require the following up of the heavy smokers by measuring their serum ACE over many years and comparing them with the pulmonary function tests to find out whether this effect is reversible on cessation of smoking and whether development of chronic bronchitis or emphysaema could be predicted. Another question that remains is whether irritants, other than cigarette smoking have the same effect on ACE. Further studies are required to clarify the actual effect of occupational air pollution and injurious dust or fumes [15] on ACE activity. On the other hand, ACE is raised in some diseases, among them sarcoidosis [16,17], hyperthyroidism [18,19] and diabetes mellitus [20,21], but the level might be depressed by chronic smoking leading to falsely lower values. It is, therefore, necessary to take a history of smoking into consideration when ACE activities are evaluated in these patients. Acknowledgements We are grateful to Dr. C. Skinner, Consultant Chest Physician, East Birmingham Hospital, for his valuable advice and Mrs. P. Jackson for secretarial help. References 1 Oparil S, Low J, Koemer JJ. Altered angiotensin I conversions in pulmonary disease. Clin Sci Mol Med 1976; 51: 537-543. 2 Lanzillo J, Fanburg BL. Angiotensin I converting enzyme from human plasma. Biochemistry 1977; 161: 5491-5495. 3 Erdos EG. Angiotensin I converting enzymes. Circulat Res 1975; 36: 247-255. 4 Studdy PR, Lapworth R, Bird R. Angiotensin converting enzyme and its clinical significance. A review. J Clin Path01 1983; 36: 938-947.
72 5 Stanley P, Birton P. Pressure response to angiotensin I during cardiopulmonary bypass. Experientia 1969; 25: 46-47. 6 Molteni A, Zakheim RM, Mullis KB, Mattioli L. The effect of chronic alveolar hypoxia on lung and serum angiotensin I converting enzyme activity. Proc Sot Exp Biol Med 1974; 147: 263-265. 7 Caldwell PRB, Seegal BC, Hsu KC, Das M, Soffer RL. Angiotensin converting enzyme: vascular endothelial localization. Science 1976; 191: 1050-1051. 8 Meu S, Takahahs M, Ohmi T, et al. Serum angiotensin converting enzyme level in bronchial asthma. Ann Allergy 1978; 40: 51-57. 9 Leuenberger PJ, Stalcup SA, Mellins RB, Greenbaim LM, Turino GM. Decrease in angiotensin I conversion by acute hypoxia in drugs. Proc Sot Exp Biol Med 1978; 158: 586-589. 10 Milledge JS, Catley DM. Resin aldosterone and converting enzyme during exercise and acute hypoxia in humans. J Appl Physiol 1982; 52: 320-323. 11 Bakkle YS, Yartiala J, Tovinson H. Votila I. Effect of cigarette smoke on the metabolism of vasoactive hormones in rat isolated lungs. Br J Pharmacol 1979; 65: 495-499. 12 Mizuno K, Yaginuma K, Hashimoto S, Tuki T. Hakamura I, Fukuch S. Acute effect of cigarette smoking on serum angiotensin converting enzyme activity in normal man. Tohoku J Exp Med 1982: 137: 113-114. 13 Friedland J, Silverstein E. Sensitive fluorimetric assay for serum angiotensin converting enzyme with the natural substrate angiotensin I. Am J Clin Path01 1977: 67: 225-229. 14 Fletcher C, Peto R, Tinker C, Speizer FE. Factors that cause irreversible airflow obstruction. In: The natural history of chronic bronchitis and emphysema, Oxford: Oxford University Press, 1976: 129-133. 15 Gronhagen-Riska C, Kurppa K, Fyhridquist F, Selroos 0. Angiotensin converting enzyme and lysozyme in silicosis and abbestos. Stand J Respir Dis 1978; 59: 228-231. 16 Studdy PR, Bird R, Neville E, James DG. Biochemical findings in sarcoidosis. J Clin Path01 1980; 33: 528-533. 17 Rohrbach MS, DeRemee RA. Pulmonary sarcoidosis and serum angiotensin converting enzyme. Mayo Clinic Proc 1982; 51: 64-66. 18 Yotsumoto H, Imai Y, Kuzuya N, Uchinmura H, Matsuzak F. Increased levels of serum angiotensin converting enzyme activity in hyperthyroidism. Ann Intern Med 1982; 96: 326-328. 19 Nakamura Y, Takeda T, Ishii M. Elevation of serum angiotensin converting enzyme activity in patients with hyperthyroidism. J Clin Endocrinol Metab 1982; 55: 931-934. 20 Liberman J, Sastra A. Serum angiotensin converting enzyme: elevations in diabetes mellitus. Ann Intern Med 1980; 93: 825-826. 21 Schernthaner G, Schwarzer CH, Kuzmits R, Muller MM, Klemen U, Freyter H. Increased angiotensin converting enzyme activities in diabetes mellitus. J Clin Path01 1984; 37: 307-312.
Clinica Chimicu Actu, 154 (1986) 69-72 Elsevier
CCA 03361
Short communication
Serum angiotensin converting enzyme activity in cigarette smokers Nuha A.A. Haboubi n Department
a, A.H.C. Bignell a and N.Y. Haboubi
b
of Clinical Chemisiry, Dudley Road Hospital, Birmingham B18 7QH and’ East Birmingham Hospital, Bordesley Green East, Birmingham B9 5ST (UK) (Received
April 9th, 1985; revision July 9th. 1985)
Key words: Kininase II; Smoking;
Lung diseases, obstructive
Summary
Low activity of angiotensin converting enzyme (ACE) has been reported in patients with smoking related diseases, such as chronic bronchitis, emphysaema and carcinoma of the lung (11 but this has not been reported in healthy, chronic smokers. Serum ACE was measured in 40 healthy cigarette smokers and in 42 healthy non-smokers. The mean value was significantly lower in the smokers. Hence a patient’s smoking habits should be taken into consideration when assessing the significance of his serum ACE levels.
Introduction
Angiotensin converting enzyme (ACE) is localised on the luminal surface of the vascular endothelial cells of the lung [2] and is produced mainly in the lung [3,4]. Several reports have suggested that alteration in angiotensin conversion occurs in pulmonary disorders or when abnormalities in pulmonary function are experimentally produced [5,6]. This raises the possibility that the reduction in converting enzyme activity may be related to a loss of vascular endothelial surface area [7]. Depressed converting enzyme activity has been reported in a variety of pulmonary diseases including bronchial asthma, cystic fibrosis, chronic bronchitis, emphysaema and bronchial carcinoma [ 1,8]. While acute hypoxia was found to inhibit ACE in both dogs [9] and humans [lo], acute exposure to cigarette smoking increases the conversion of angiotensin I and angiotensin II in rat isolated lung [ll] and in humans [12]. The chronic effect of cigarette smoking on the ACE has not been described. The aim of this study was to document ACE activity in chronic cigarette smokers. 0009-8981/86/$03.50
0 1986 Elsevier Science Publishers
B.V. (Biomedical
Division)
Patients and methods
Volunteers from the hospital medical, nursing, clerical, auxiliary and laboratory staff were studied. There were 40 smokers and 42 non-smokers. The former group had smoked over 15 middle tar cigarettes daily for at least 10 yr; none of the latter had ever smoked. None of the subjects had a history of hypertension, diabetes, lung or thyroid disease. The smokers were 20 males and 20 females. Their mean age was 33.05 yr (range 27-45). The non-smokers were 22 males and 20 females. Their mean age was 32.19 yr (range 25-45). Blood samples were taken from the smokers at least 1 h after smoking to eliminate any acute effect of smoking on the activity of the enzyme [12]. Serum ACE acti&ies were determined fluorimetrically according to the method of Friedland and Silverstein using hippuryl-L-histidyl-L-leucine as substrate [13] (Sigma Chemical Co., Dorset, UK). Serum ACE was measured in duplicate. Results are reported as pmol/l (pm01 of hippuric acid liberated/mm per 1 of serum). The within-batch coefficient of variation (CV) for 200 assays was 6% and between batch for 20 assays in duplicate was 8.5% (mean value 35). 60
. .. ..
55
--a..
50
.‘. ..
45
&O
35
.. . A
30
.Y .
20
15
10
.. . . . SMOKERS GROUP
NON-SMOKERS GROUP
Fig. 1. Scattergram of serum ACE activity in healthy smokers and healthy non-smokers. The long horizontal bars represent the values of the mean and the short ones represent 1 SD in each group.
71
Results The mean value of serum ACE activity (Fig. 1) for the smokers was 31.1 pmol/l 8.14). For the non-smokers the mean value was 40.8 pmol/l (SD 10.78). The t test of the two groups gave a value of 4.6112 for which p < 0.001. All of these results lay within our normal laboratory reference range (8-59 pmol/l), which was obtained from healthy volunteers without taking into consideration their smoking habits. There was no significant difference in the ACE activities between the male and female subjects.
(SD
Discussion The two groups which we have studied were all healthy personnel from the hospital staff. Smoking is known to have numerous adverse effects on lung tissue some of which are well-documented. However, the direct effect of cigarette smoking on the pulmonary capillary bed is not clear. We have shown that serum ACE activities are reduced in chronic smokers. The mechanism of this reduction may be that smoking either destroys the endothelial cells which release ACE into the pulmonary circulation or inhibit the release of the enzyme. These results require the following up of the heavy smokers by measuring their serum ACE over many years and comparing them with the pulmonary function tests to find out whether this effect is reversible on cessation of smoking and whether development of chronic bronchitis or emphysaema could be predicted. Another question that remains is whether irritants, other than cigarette smoking have the same effect on ACE. Further studies are required to clarify the actual effect of occupational air pollution and injurious dust or fumes [15] on ACE activity. On the other hand, ACE is raised in some diseases, among them sarcoidosis [16,17], hyperthyroidism [18,19] and diabetes mellitus [20,21], but the level might be depressed by chronic smoking leading to falsely lower values. It is, therefore, necessary to take a history of smoking into consideration when ACE activities are evaluated in these patients. Acknowledgements We are grateful to Dr. C. Skinner, Consultant Chest Physician, East Birmingham Hospital, for his valuable advice and Mrs. P. Jackson for secretarial help. References 1 Oparil S, Low J, Koemer JJ. Altered angiotensin I conversions in pulmonary disease. Clin Sci Mol Med 1976; 51: 537-543. 2 Lanzillo J, Fanburg BL. Angiotensin I converting enzyme from human plasma. Biochemistry 1977; 161: 5491-5495. 3 Erdos EG. Angiotensin I converting enzymes. Circulat Res 1975; 36: 247-255. 4 Studdy PR, Lapworth R, Bird R. Angiotensin converting enzyme and its clinical significance. A review. J Clin Path01 1983; 36: 938-947.
72 5 Stanley P, Birton P. Pressure response to angiotensin I during cardiopulmonary bypass. Experientia 1969; 25: 46-47. 6 Molteni A, Zakheim RM, Mullis KB, Mattioli L. The effect of chronic alveolar hypoxia on lung and serum angiotensin I converting enzyme activity. Proc Sot Exp Biol Med 1974; 147: 263-265. 7 Caldwell PRB, Seegal BC, Hsu KC, Das M, Soffer RL. Angiotensin converting enzyme: vascular endothelial localization. Science 1976; 191: 1050-1051. 8 Meu S, Takahahs M, Ohmi T, et al. Serum angiotensin converting enzyme level in bronchial asthma. Ann Allergy 1978; 40: 51-57. 9 Leuenberger PJ, Stalcup SA, Mellins RB, Greenbaim LM, Turino GM. Decrease in angiotensin I conversion by acute hypoxia in drugs. Proc Sot Exp Biol Med 1978; 158: 586-589. 10 Milledge JS, Catley DM. Resin aldosterone and converting enzyme during exercise and acute hypoxia in humans. J Appl Physiol 1982; 52: 320-323. 11 Bakkle YS, Yartiala J, Tovinson H. Votila I. Effect of cigarette smoke on the metabolism of vasoactive hormones in rat isolated lungs. Br J Pharmacol 1979; 65: 495-499. 12 Mizuno K, Yaginuma K, Hashimoto S, Tuki T. Hakamura I, Fukuch S. Acute effect of cigarette smoking on serum angiotensin converting enzyme activity in normal man. Tohoku J Exp Med 1982: 137: 113-114. 13 Friedland J, Silverstein E. Sensitive fluorimetric assay for serum angiotensin converting enzyme with the natural substrate angiotensin I. Am J Clin Path01 1977: 67: 225-229. 14 Fletcher C, Peto R, Tinker C, Speizer FE. Factors that cause irreversible airflow obstruction. In: The natural history of chronic bronchitis and emphysema, Oxford: Oxford University Press, 1976: 129-133. 15 Gronhagen-Riska C, Kurppa K, Fyhridquist F, Selroos 0. Angiotensin converting enzyme and lysozyme in silicosis and abbestos. Stand J Respir Dis 1978; 59: 228-231. 16 Studdy PR, Bird R, Neville E, James DG. Biochemical findings in sarcoidosis. J Clin Path01 1980; 33: 528-533. 17 Rohrbach MS, DeRemee RA. Pulmonary sarcoidosis and serum angiotensin converting enzyme. Mayo Clinic Proc 1982; 51: 64-66. 18 Yotsumoto H, Imai Y, Kuzuya N, Uchinmura H, Matsuzak F. Increased levels of serum angiotensin converting enzyme activity in hyperthyroidism. Ann Intern Med 1982; 96: 326-328. 19 Nakamura Y, Takeda T, Ishii M. Elevation of serum angiotensin converting enzyme activity in patients with hyperthyroidism. J Clin Endocrinol Metab 1982; 55: 931-934. 20 Liberman J, Sastra A. Serum angiotensin converting enzyme: elevations in diabetes mellitus. Ann Intern Med 1980; 93: 825-826. 21 Schernthaner G, Schwarzer CH, Kuzmits R, Muller MM, Klemen U, Freyter H. Increased angiotensin converting enzyme activities in diabetes mellitus. J Clin Path01 1984; 37: 307-312.