EFFECTS OF CIGARETTE SMOKING ON SERUM-LIPIDS, BLOOD-GLUCOSE, AND PLATELET ADHESIVENESS

182

of

postoperative hypoxaemia is supported by the experiof Gordh et al. (1958), who found alveolar-arterial oxygen-tension gradients were greater when patients breathed 100% oxygen after major abdominal surgery than beforehand-indicating the presence of shunting past non-ventilated alveoli. We are exploring this possibility

ments

further.

Summary Arterial

tensions and

blood-gas spirometric measuremade preoperatively and on the first postoperative day on 180 patients undergoing varying operations. The mean fall in Pa02 was 18-6 (±11-6) mm. Hg after upper-abdominal surgery, 9-5 (rlO’0) mm. Hg after low-abdominal surgery, and 5-7 (±10-8) mm. Hg after non-abdominal surgery. Slight hypercapnia occurred only after upper-abdominal surgery. The correlation between the degree of hypoxxmia and the restrictive ventilatory defect was not a strong one.

ments were

We thank Prof. G. Smith, Prof. 1. MacGillivray, Mr. N. J. Logie, and Mr. W. Michie and the other consultant surgeons of The Aberdeen Royal Infirmary for their cooperation and for allowing us to examine the patients under their care; Miss S. MacRae for technical assistance; and to the Vaughan Hudson Clinical Trust for their generous help in the purchase of apparatus. Requests for reprints should be addressed to Dr. K. N. V. Palmer, Department of Medicine, Foresterhill, Aberdeen. REFERENCES

Bendixen, H. H., Hedley-Whyte, J., Laver, M. B. (1963) New Engl. J. Med. 269, 991. Committee on Rating of Mental and Physical Impairment: the Respiratory System (1965) J. Am. med. Ass. 194, 177. Gardiner, A. J. S., Palmer, K. N. V. (1964) Br. med. J. ii, 1443. Gordh, T., Linderholm, H., Norlander, O. (1958) Acta anœsth. scand. 2, 15. Hamilton, W. K., McDonald, J. S., Fischer, H. W., Bethards, R. (1964) Anesthesiology, 25, 607. Maier, H. C., Cournand, A. (1943) Surgery, St. Louis, 13, 199. Nunn, J. F., Payne, J. P. (1962) Lancet, ii, 631. Palmer, K. N. V., Gardiner, A. J. S. (1964) Br. med. J. i, 347. McGregor, M. H. (1965) Thorax, 20, 73. Taylor, S. M., Scott, D. B., Donald, K. W. (1964) Lancet, i, 841.

1966). Since these are factors affected by cigarette smoking the present investigation was instituted to determine the short-term effect of cigarette smoking on all these factors and the relationship between them. son

Patients and Methods 12 patients (8 males and 4 females) from a general medical ward who habitually smoked ten or more cigarettes daily were investigated. They were aged from 37 to 67 years with a mean age of 55 years. Diagnoses were: ischaemic heart-disease (3), peripheral arterial disease (3), hypertension, idiopathic diarrhoea, simple goitre, rheumatic heart-disease, epilepsy, and

pneumonia. The patients fasted overnight and remained at rest in bed throughout the experiment. Two basal venous blood-samples were taken 20 minutes apart. The patients were then instructed either to smoke two of their usual brand of cigarettes during a 15-minute period or to sham smoke by puffing the unlit cigarette for the same length of time. A third blood-sample was taken at the end of the 15-minute period, and three further samples at 10-minute intervals. Within the next few days the experiment was repeated with sham-smoking substituted for smoking and vice versa. 7 patients smoked in the first experiment, and 5 in the second. Platelet adhesiveness was measured by a method based on that of Payling Wright (1941), using 2 ml. of citrated blood (1 part 3-8% sodium citrate to 9 parts blood) rotated in a spherical flask at 31/2 r.p.m. for 20 minutes, commencing 5 minutes after venepuncture. Platelet counts were done by direct counting of whole blood using 1% ammonium oxalate and phase-contrast microscopy (Brecher and Cronkite 1950). The percentage of adhesive platelets was expressed as:

Blood-glucose and serum-total-cholesterol were deterby the TechniconAutoAnalyser ’ methods. Serumtriglycerides were measured by the method of van Handel and Zilversmit (1957). The plasma-nonesterified-fatty-acid (N.E.F.A.) was estimated on heparinised blood by a modified Dole method, following the technique of Dole and Meinertz (1960) but using Nile-blue as indicator. For determination of the individual nonesterified fatty acids, the N.E.F.A. fraction was separated by thin-layer chromatography using plates coated EFFECTS OF CIGARETTE SMOKING ON withAdsorbosil’impregnated with rhodamine B. The SERUM-LIPIDS, BLOOD-GLUCOSE, solvent system used was hexane/diethyl-ether/methanoll acetic-acid in the proportions of 90 :20 :3 :2 v/v. The N.E.F.A. AND PLATELET ADHESIVENESS band was scraped from the plate and the fatty acids were LILIAN E. MURCHISON T. FYFE eluted with ether, then methylated by methanol and sulphuric M.B. Edin. M.B. Glasg. acid. The fatty acids were separated by gas liquid chromatoMEMBERS OF THE SCIENTIFIC STAFF, THE MEDICAL RESEARCH COUNCIL graphy on a‘ Panchromatograph ’column containing 15°o ATHEROMA RESEARCH UNIT, WESTERN INFIRMARY, GLASGOW W. 1 polyethyleneglycol adipate ownGas Chron P ’. Student’s t test was used to analyse the significance of changes THE association between cigarette smoking and in levels of the plasma constituents from the mean basal levels. mortality from ischmmic heart-disease (British Medical For blood-glucose, since there was a small rise in the basal Journal 1966) has led to numerous speculations as to the the 20-minute level was taken as the baseline. period, mechanism. Besides the well-known circulatory effects of Results cigarette smoking some investigators (Gofman et al. 1955, Karvonen et al. 1959, Bronte-Stewart 1961) have shown The results of the 12 smoking-tests are shown in table I, an association with elevated serum-lipids while others and those of the 12 sham-smoking tests in’table 11. There was a significant rise in the mean plasma N.E.F.A, (Doyle et al. 1962, Mulcahy et al. 1963) found no such relationship. Other reported effects of cigarette smoking level after smoking, reaching a maximum 10 minutes after have included elevation of the blood-glucose (Lundberg the end of the smoking-period, and falling again to the basal level over the succeeding 20 minutes. While the and Thyselius-Lundberg 1931), increased platelet adhesiveness (Ashby et al. 1965), and decreased platelet survival plasma-N.E.F.A. level increased to a variable extent in every has case after smoking, after sham-smoking the plasmaPlatelet adhesiveness and (Mustard Murphy 1963). N.E.F.A. level rose in 5 cases, was unchanged in 3, and fell also been shown to be increased in ischaemic heartin 4. The small increase after sham-smoking was not disease (Macdonald and Edgill 1957, Owren et al. 1964). The factors responsible for platelet adhesiveness are statistically significant. not completely established, but some which have been Both smoking and sham-smoking were followed bya are suggested blood-glucose (Bridges et al. 1965) and significant increase in the concentration of oleic acid in the various plasma-lipid components including triglyceride N.E.F.A. fraction, and a significant fall in the concentration (Philp and Payling Wright 1965) and fatty acids (Thomp- of palmitic acid. This effect was more notable after sham—

—

mined

183 TABLE I-MEAN

(IS.D.)

TABLE II-MEAN

OF CHANGES AFTER CIGARETTE SMOKING

(S.D.)

OF CHANGES AFTER SHAM SMOKING

smoking than after smoking, and did not correlate well with the changes in total plasma-N.E.F.A. The other fatty acids in the N.E.F.A. fraction showed a similar tendency for

increase in unsaturated at the expense of saturated fatty acids, but the individual changes were not significant. There was no significant change in serum-cholesterol and triglyceride levels in either group. Smoking was followed by a small but significant increase in blood-glucose. This happened in every case and showed no tendency to return to the fasting level. There was no change after sham-smoking. There was a significant, transient rise in the total platelet count after smoking, but no change after shamsmoking. On the other hand, there was a mean rise in platelet adhesiveness in both smoking and sham-smoking groups. There was an increase in 9 of the 12 shamsmoking tests, and in this group the mean rise was significant. The change after smoking was more variable, a rise in 7 cases and a fall in 5 cases, and the mean rise an

was not

There

statistically significant. was no significant difference between the

6

serum-lipid levels, blood-glucose, and platelet adhesiveness, or in the magnitude of the responses to smoking. There was no correlation between basal platelet adhesiveness and basal levels of either glucose or N.E.F.A. In the sham-smoking group it was evident that there was a good correlation between the percentage rise in N.E.F.A. and the rise in platelet adhesiveness, as shown in fig. 1:

This correlation was significant at the 100 level There was a similar, but less significant, correlation between percentage changes in N.E.F.A. and platelet adhesiveness after smoking (r=0-584, P < 005) as shown in fig. 2. In the smoking group, however, there was a rise in glucose and fig. 3 illustrates the negative correlation between changes in blood-glucose and platelet The relationship adhesiveness (r=0-701, P<0-02). between the % change in platelet adhesiveness (y) and % changes in N.E.F.A. (xi) and blood-glucose (x2) after smoking can be expressed as follows:

(r=0-709).

patients with arterial disease and the others in basal

Fig. 1—Correlation between percentage changes in plasma-N.E.F.A. and platelet adhesiveness after sham smoking.

Fig. 2-Correlation between percentage changes in plasma-N.E.F.A. and platelet adhesiveness after smoking.

Fig. 3-C orrelation between percentage changes in blood-glucose and platelet adhesiveness after smoking.

y=0’51x-9-19 (r=0-7091).

y=O’86x-8’22 (r==0’5838).

y=3-6x-r 46 (r=-0-7011).

184

the work of Hellem (1960) who was unable to demonstrate any effect within the physiological range for glucose. We have not confirmed the findings of Ashby et al. of a significant increase in platelet adhesiveness (1965) Discussion after smoking. Although 7 cases showed a considerable The significant rise in plasma-N.E.F.A. after smoking, rise in platelet adhesiveness following smoking, in 5 others with no significant alteration in cholesterol and tri- in whom there was a marked rise in glucose the platelet glyceride, confirms the findings of previous workers adhesiveness fell. This effect was more evident in 2 (Kershbaum et al. 1961). It is interesting that sham- patients who felt nauseated at the end of the smokingsmoking was followed by a similar rise in plasma-N.E.F.A. period and who showed the largest increase in bloodin 5 of the 12 tests. The fact that the rise followed a glucose in association with delay in N.E.F.A. rise. Since steady basal period suggests that the effect was due to Ashby et. al (1965) only measured platelet adhesiveness it is sham smoking rather than repeated venepuncture, and not possible to explain the discrepancy between his results might possibly be due to the embarrassment of puffing and ours. It may be, however, that in the non-fasting state an unlit cigarette. The fact that sham smoking may the blood-glucose response to smoking is less striking, produce physiological changes was recognised by Irving The somewhat surprising finding of a significant increase and Yamamoto (1963) in their investigation of the effects in platelet adhesiveness after sham smoking is clearly of cigarette smoking on cardiac output. associated with the unopposed effect of the rise in N.E.F,A, An increase in unsaturated fatty acids at the expense of on which we have already commented. saturated fatty acids has been found by other investiSummary gators when the total plasma N.E.F.A. is raised by stimuli Platelet adhesiveness, blood-glucose and plasma-lipids other than smoking (Rothlin et al. 1962, Wood et al. were estimated in 12 patients before and after 1965). It is somewhat surprising that the change after and sham smoking. Cigarette smoking elevatedsmoking plasma sham smoking was more striking than that after smoking, levels and resulted in an increase nonesterified-fatty-acid and that the change in pattern does not correlate well with in the proportion of unsaturated fatty acids at the expense the change in total plasma-N.E.F.A. level. of the saturated fatty acids. Smoking was also followed by Some earlier workers reported that cigarette smoking a significant rise in blood-glucose and a transient increase elevated the blood-glucose (Lundberg and Thyselius- in the total platelet count. The variable effect of smoking Lundberg 1931) but Rehder and Roth (1959) have on platelet adhesiveness seemed to be due to opposing suggested that the rise shown was due to stress rather actions of changes in nonesterified fatty acid and glucose than an effect of smoking. In our series the rise can be levels. A rise in plasma nonesterified fatty acid was attributed to smoking per se. with increased associated platelet adhesiveness, whereas The increased platelet count after smoking also seems a rise in glucose inhibited platelet adhesiveness. to be a nicotine effect. This effect has previously been We thank Miss Eleanor Hamilton, Miss Joan Munro, and Mr. A. reported in an uncontrolled study by Grassi and Calta- Wilson for technical assistance; Dr. E. B. Hendry for the bloodbiano (1956). The mechanism is obscure, but may be a glucose measurements; Dr. R. A. Robb for statistical advice; and Sir Edward Wayne and the other members of our unit for advice result of adrenaline release (Vaughan-Jones et al. 1963). and encouragement. Platelet adhesiveness is known to be increased after Requests for reprints should be addressed to Dr. T. Fyfe, myocardial infarction (Macdonald and Edgill 1957) and Atheroma Research Unit, Western Infirmary, Glasgow W.1. in disseminated sclerosis (Caspary et al. 1965, Payling REFERENCES Wright et al. 1965) and, since fatty-acid abnormalities Ashby, P., Dalby, A. M., Millar, J. H. D. (1965) Lancet, ii, 158. have also been demonstrated in these conditions (James Brecher, G., Cronkite, E. P. (1950) J. appl. Physiol. 3, 365. Bridges, J. M., Dalby, A. M., Millar, J. H. D., Weaver, J. A. (1965) Lancet, et al. 1957, Thompson 1966), a relationship between i, 75. Medical Journal (1966) i, 755. platelet adhesiveness and serum-fatty-acids has been British Bronte-Stewart, B. (1961) Brit. med. J. i, 379. The has been the proposal supported by suggested. Caspary, E. A., Prineas, J., Miller, H., Field, E. J. (1965) Lancet, ii, 1108. in-vitro work of Kerr et al. (1965), who showed that Dole, V. P., Meinertz, H. (1960) J. biol. Chem. 235, 2595. J. T., Dawber, T. R., Kannel, W. B., Heslin, A. S., Kahn, H. A. (1962) saturated fatty acids induced greater platelet aggregation Doyle, New Engl. J. Med. 266, 796. than unsaturated fatty acids, some of which seemed to Gofman, J. W., Lindgren, F. T., Strisower, B., Delalla, O., Glazier, F., Tamplin, A. (1955) Geriatrics, 10, 349. have an inhibitory effect. Our results show that when the Grassi, B., Caltabiano, S. (1956) Rass. Fisiopat. clin. ter. 28, 755. blood-glucose remained constant there was a good correla- Hellem, A. J. (1960) Scand. J. clin. Lab. Invest. 12, suppl. 51, p. 43. Irving, D. W., Yamamoto, T. (1963) Br. Heart J. 25, 126. tion between the changes in platelet adhesiveness and the James, A. T., Lovelock, J. E., Webb, J., Trotter, W. R. (1957) Lancet, changes in N.E.F.A. When the blood-glucose also altered i, 705. M., Orma, E., Keys, A., Fidanza, F., Brozek, J. (1959) ibid. (in the smoking-test) the relationship between the changes Karvonen, i, 492. in platelet adhesiveness and N.E.F.A. was less close. In Kerr, J. W., Pirrie, R., MacAulay, I., Bronte-Stewart, B. (1965) ibid. i, 1296. this situation, the rise in blood-glucose seemed to have a Kershbaum, A., Bellet, S., Dickstein, E. R., Feinberg, L. J. (1961) Circula-

Using this formula, the correlation between actual and predicted values for platelet adhesiveness is significant at the 1% level (r=0726).

:

suppressive effect on platelet adhesiveness, since there was a negative correlation between the changes in bloodglucose and platelet adhesiveness. Bridges et al. (1965) showed that platelet adhesiveness increased after an oral glucose load, but he was unable to show a correlation between the rise in blood-glucose and the rise in platelet adhesiveness. This situation, however, is quite different to the present one in which endogenous glucose is being mobilised. Bridges et al. (1965) also showed that the addition of glucose in vitro resulted in an increase in platelet adhesiveness, but this is contrary to

tion Res. 9, 631. Lundberg, E., Thyselius-Lundberg, S. (1931) Acta med. scand. suppl. 38, p.1. Macdonald, L., Edgill, M. (1957) Lancet, ii, 457. Mulcahy, R., Goff, A., Hickey, N. (1963) J. Ir. med. Ass. 53, 141. Mustard, J. F., Murphy, E. A. (1963) Br. med. J. i, 846. Owren, P. A., Hellem, A. J., Odegaard, A. E. (1964) Lancet, ii, 975. Payling Wright, H. (1941) J. Path. Bact. 53, 255. Thompson, R. H. S., Zilka, K. J. (1965) Lancet, ii, 1109. Philp, R. B., Payling Wright, H. (1965) ibid. p. 208. Render, K., Roth, G. M. (1959) Circulation, 20, 224. Rothlin, M. E., Rothlin, C. B., Wendt, V. E. (1962) Am. J. Physiol. 203, 306. Thompson, R. H. S. (1966) Proc. R. Soc. Med. 59, 269. van Handel, E., Zilversmit, D. G. (1957) J. Lab. clin. Med. 50, 152. Vaughan-Jones, R., Ingram, G. I. C., McClure, P. D. (1963) Abstracts on the Congress of the Society of Hæmatology. Lisbon. Wood, P., Schlierf, G., Kinsell, L. (1965) Metabolism, 14, 1095. —