RELATIVE CHANGES IN FREE-FATTY-ACID AND GLUCOSE UTILISATION BY ISCHÆMIC MYOCARDIUM AFTER CORONARY-ARTERY OCCLUSION

1187 stronger, but still indirect, evidence that iron-overload has a pathogenic role in p.c.T. Yet, porphyria is not ordinarily associated with idiopathic haemochromatosis. Moreover, in P.C.T. with siderosis, the amount of blood that must be removed to produce clinical improvement and biochemical remission of porphyrinuria generally corresponds to only about 3 to 4 g. of elemental iron. In the few phlebotomyinduced remissions in which follow-up liver biopsies have been obtained (Hickman et al. 1967, Strickland 1968," Taddeini and Watson 1968), as in our patients 1 and 3, the treatment did not completely alleviate the hepatic siderosis; and the case briefly mentioned by Taddeini and Watson (1968) showed virtually no diminution at all in hepatic iron. The degree of hepatic siderosis in P.C.T. seems to fall somewhere between that in classic haemochromatosis (20 g. or more) and that in Laennec’s cirrhosis with siderosis, in which withdrawal of 1 or 2 g. of iron is usually sufficient to make the patient clearly iron-deficient (Williams et al. 1967, Conrad 1968). Consistent with this intermediate placement of P.C.T. are the modestly elevated deferoxamine values found in the present study. Finally, phlebotomy therapy seems to be successful in P.C.T. even when there is no demonstrable siderosis (Epstein and Redeker 1968). Perhaps, then, simple iron withdrawal is not the critical factor which determines the response to phlebotomy therapy. The results of therapy with specific iron chelators -e.g., deferoxamine-have been mixed (Saunders 1963,-’ Thivolet et al. 1968). In evaluating these results, one factor that has received belated emphasis is the drinking habits of the patients under treatment (Hickman et al. 1967, Epstein and Redeker 1968); for it has long been known (Brunsting 1954) that patients with P.C.T. may improve considerably merely by abstaining from alcohol. Patients who continue to drink, however, do not usually improve spontaneously (Hickman et al. 1967). Of the three patients reported here, one never drank, one used to drink but stopped, and one continued to drink while undergoing phlebotomies, yet all three achieved nearly complete remissions. On the basis of all the existing evidence, the following conclusions seem justified. Mild-to-moderate hepatic siderosis is found in the great majority of both alcoholic and nonalcoholic patients with P.C.T., and appears relatively early in the course-i.e., before frank cirrhosis. Siderosis need not necessarily be completely eliminated to obtain remission of the porphyria; and it may be linked in some manner with abnormalities in marrow-haem production. Furthermore, irrespective of haemosiderosis, alcoholic patients with P.C.T. who merely stop drinking may show clinical and biochemical improvement; those who continue to drink probably will not show much change or will worsen; those who continue to drink, and who have multiple phlebotomies, will, in most cases, show clinical and biochemical improvement; and those who stop drinking and undergo phlebotomies will probably have the best and most lasting improvement. Precisely how phlebotomies contribute to these patients’ remissions remains unknown. Therapeutic studies employing plasmapheresis may provide a clue. This work was supported by the United States Public Health National Cancer Institute grant no. 5501 CA 05003. We gratefully acknowledge the able technical assistance of Mr. Peter Stavropoulos and Mrs. Marie Clark. Requests for reprints should be addressed to J. T. K., Dermatology Department, King’s College Hospital, London S.E.5.

Service,

RELATIVE CHANGES IN FREE-FATTY-ACID AND GLUCOSE UTILISATION BY ISCHÆMIC MYOCARDIUM AFTER CORONARY-ARTERY OCCLUSION PATRICIA OWEN

MICHAEL THOMAS

LIONEL OPIE FROM THE MEDICAL RESEARCH COUNCIL CARDIOVASCULAR RESEARCH ROYAL POSTGRADUATE MEDICAL

UNIT,

SCHOOL, LONDON W.12

Because the survival of ischæmic heart-

Summary tissue may be influenced by the relative

utilisation of glucose and free fatty acids (F.F.A.), experiments were designed to compare the handling of these substrates by ischæmic and non-ischæmic myocardium in identical experimental circumstances. The arteriovenous difference of glucose across the ischæmic zone increased, while that of F.F.A. was unchanged. This implies increasing emphasis on the utilisation of glucose, relative to that of F.F.A., by the ischæmic heart-tissue. The observations may be relevant to the role of glucose in the treatment of patients with acute myocardial infarction. Introduction IN patients with acute myocardial infarction, the survival of ischaemic heart-tissue may be influenced by the relative utilisation of circulating glucose and free fatty acid (F.F.A.). In the normally oxygenated heart, the major sources of energy are circulating F.F.A., glucose, and lactate (Bing 1954, Harris et al. 1964), and F.F.A. is usually utilised in preference to glucose (Shipp, Opie, and Challoner 1961). In anoxic heart-tissue, the only pathway known to provide energy is anaerobic glycolysis from glucose or glycogen with the production of lactate (Scheuer 1967). Glucose is the only known exogenous substrate which can be utilised by the isolated heart totally deprived of oxygen, and the extent of the utilisation of glucose may govern the survival of the anaerobic heart (Cascarano et al. 1968, Mansford 1968, Weissler et al. 1968). It follows that the transition from aerobic to anaerobic metabolism may be accompanied bya shift from F.F.A. to glucose as the substrate used in the provision of energy. The degree to which this shift occurs in acutely ischaemic myocardium is relevant to the recently raised possibilities that the utilisation of F.F.A. (Oliver et al. 1968) or the administration of glucose (Mittra 1965) may DR. KALIVAS AND OTHERS: REFERENCES

Brunsting, L. A. (1954) Archs Derm. Syph. 70, 551. Conrad, M. E. (1968) Med. Ann. Distr. Columbia, 37, 15. Epstein, J. H., Redeker, A. G. (1968) New Engl. J. Med. 279, 1301. Felsher, B. F., Redeker, A. G. (1966) Archs intern. Med. 118, 163. Goodman, J. R., Hall, S. G. (1967) Br. J. Hœmat. 13, 335. Hickman, R., Saunders, S. J., Eales, L. (1967) S. Afr. med. J. 41, 456. Horrigan, D. L., Harris, J. W. (1964) Adv. intern. Med. 12, 103. Ippen, H. (1961) Dt. med. Wschr. 86, 127. Jean, G., Lambertenghi, G., Ranzi, T. (1968) J. clin. Path. 21, 501. Kyle, R. A., Bowie, E. J. W., Brunsting, L. A. (1964) Proc. Staff Meet. Mayo Clin. 39, 750. Price, D. C., Epstein, J. H., Winchell, H. S., Sargent, T. W., Pollycove, M., Cavalieri, R. R. (1968) Clin. Res. 16, 124. Rosen, B. J., Tullis, J. L. (1966) J. Am. med. Ass. 195, 261. Saunders, S. J. (1963) S. Afr. J. lab. clin. Med. 9, 277. Schirren, C., Strohmeyer, G., Wehrmann, R., Wiskemann, A. (1966) Dt. med. Wschr. 91, 1344. Schwartz, S., Berg, M. H., Bossenmaier, I., Dinsmore, H. (1960) Methods biochem. Anal. 8, 221. Strickland, G. T. (1968) Am. J. Gastroent., N.Y. 50, 202. Taddeini, L., Watson, C. J. (1968) Sem. Hœmatol. 5, 335. Thivolet, J., Perrot, H., Mallein, R., Sabater, P. (1968) Presse méd. 76, 367. Tschudy, D. P. (1965) J. Am. med. Ass. 191, 718. Williams, R., Williams, H. S., Scheuer, P. J., Pitcher, C. S., Loiseau, E. Sherlock. S. (1967) Q. Jl Med. 36, 151.

1188

influence the survival of patients with acute myocardial infarction. Since the relative utilisation of substrates by the myocardium after coronary occlusion requires further

designed experiments to compare the glucose, and lactate by ischaemic and non-ischaemic myocardium.

definition,

handling of

we

F.F.A.,

Methods Twelve greyhounds, fasted overnight, were anaesthetised by intravenous thiopentone sodium (’Pentothal’), followed by intravenous pentobarbitone sodium (’Nembutal’). Under radiological control, a catheter (Goodale-Lubin, U.S. Catheter Corporation) was passed into the coronary sinus. A large-bore plastic catheter was inserted into the femoral artery. The heart was exposed through a left thoracotomy; respiration was maintained on room air by a Harvard respiration pump through a cuffed endotracheal tube. The parietal pericardium was incised and, with limited dissection, a silk ligature was loosely placed around an anterolateral branch of the left interventricular descending coronary artery. A polyethylene catheter (PE 60, ’Intramedic ’, Clay Adams, U.S.A.) was passed into the vena comitans of the arterial branch using a Seldinger method. The catheter lumen was kept patent by frequent gentle flushing with a very dilute heparin solution (about 1 unit per ml.). An epicardial electrocardiograph (E.C.G.) lead was attached within the zone of distribution of the arterial branch. After the above preparation, at least thirty minutes elapsed before serial blood-samples were taken from the femoral artery, the coronary sinus, and the local coronary vein. The coronaryartery branch was then ligated and further samples taken for 1-2 hours. Glucose was analysed by the glucose-oxidase method. Plasma-F.F.A. was titrated by a modification of the technique of Dole (Chlouverakis 1963). Added internal F.F.A. standards gave 85-95% recoveries. To measure triglycerides, about 5 ml. of blood was centrifuged at 4°C, and 0-5 ml. of the serum immediately added to 25 ml. cooled chloroform/ methanol by volume (2/1). The mixture was stored at 4°C until assayed by the method of Sardesai and Manning (1968). Added internal standards gave recoveries of about 95%. Blood-lactate was determined enzymatically (Horn and Bruns 1956) on the supernatant of blood deproteinised immediately after sampling in 6 ml. ice-cold perchloric acid (0’7M).

Fig. 2-Relationship of arterial F.F.A. concentration

to

arterial/

local-venous F.F.A. difference.

Note linear relationship and similar regression line for observations before and after arterial occlusion.

and Lapin 1966). In considering uptake and discharge of different substances measured in the same blood-sample, since blood-flow factors are common to each, the relative utilisation of two substrates may be defined with precision in the absence of any measurements of blood-flow. son

Biochemical Results

(i) Plasma-F.F.A.-Control values for plasma-F.F.A. in eleven dogs ranged from 200 to 1700 .moles per litre. The arteriovenous differences for both the local vein (fig. 2) and the coronary sinus were linearly related to the arterial concentration, both before and after ligation. The arterial/local-vein and arterial/coronary-sinus differences were the same throughout (fig. 3). After local coronary-

Results

The small arterial occlusion led to acute sT-segment elevation in the epicardial E.C.G. (fig. 1). Metabolic changes in the local vein dominantly reflected the consequences of ischaemia in the segment of heart supplied by the anterolateral arterial branch. The volume of ischaemic myocardium was usually 3-10% of the whole. Coronarysinus blood-samples reflected metabolic events in the major non-ischaemic part of the heart and only rarely showed changes found in the local vein. The essential measurements were the concentrations of substrates in the arterial,

local-venous, and coronary-sinus blood. For a of the absolute uptake or discharge of a substrate, a knowledge of blood-flow is also required. Thirty to sixty minutes after coronary-artery occlusion, blood-flow is reduced to about 30-40% of control values (Rees measurement

Fig.

I-Diagram

showing

small

ischaemic zone of myocardium, with example of epicardial E.C.G. with ST-segment elevation, after occlusion of a small anterolateral branch of the left anterior descending coronary artery.

and Redding 1968, Gray-

Fig. 3-Percentages (S.E. of means) of arterial F.F.A. concentration extracted by ischmmic zone (local vein) and whole heart (coronary sinus); there are no significant differences between local-vein or coronarv-sinus values before

or

after arterial occlusion.

artery occlusion, the percentage uptake across the ischxmic zone of the myocardium (local-vein samples) and across the whole heart (coronary-sinus samples) was unchanged. The unchanged arteriovenous values after coronary occlusion were independent of the control plasma-F.F.A. values despite the wide range of arterial values. A study of the F.F.A. arteriovenous differences across a small ischaemic zone was also made before and after additional occlusion of the adjacent arteries on either side of the test zone (fig. 4). Both initial and later occlusions were not followed by changes in the arteriovenous values. In this experiment, a total of 25% of the heart was rendered ischxmic. In all the above experimental circumstances,

1189

have no consistent effect on triglyceride extraction by either the ischaemic or the nonischsemic zone. Because of the small and variable uptake of triglyceride by ischoemic and non-ischxmic zones, it is unlikely that degradation of triglyceride contributed substantially to metabolism of the heart in these experiments. However, the use of small amounts of heparin for flushing purposes could have decreased myocardial triglyceride to

uptake (Enser, Kunz, Borensztajn, Opie, and Robinson 1967). (iv) Blood lactate.-Before ligation, the arterial-lactate concentration was always greater than the local-vein value, which was similar to the coronary-sinus value. After arterial occlusion, local-vein but not coronarysinus lactate concentration exceeded the arterial-lactate concentration in all experiments except 1. Discussion

These experiments were designed to show the relative utilisation of substrates by Following occlusion of anterolateral arterial branch, arterial branches on either side ischaemic and non-ischaemic myocardium. of test zone were successively occluded. After initial arterial occlusion, arterial/ After arterial occlusion, the arteriovenous local-venous difference of glucose increased but that of F.F.A. was unchanged. difference of plasma-F.F.A. did not change but that of glucose increased by 3-4 times (figs. the venous F.F.A. plasma-concentrations were about 3-5). The uptake of glucose by the ischaemic zone also increased 3-4 times relative to that of F.F.A. There seemed 50-60% of the arterial values. to be an increasing emphasis on the utilisation of glucose (ii) Plasma-glucose.-In the same dogs, the arteriovenous by the ischaemic heart-tissue; the contribution of F.F.A. was difference of glucose before ligation was small, with a mean relatively decreased, while lactate made no contribution at value of 5-6 mg. per 100 ml. (fig. 5). After ligation, the all. In absolute terms, the utilisation of F.F.A. was decreased local-vein plasma-glucose concentration fell in 10 of 12 the same factor as that by which the blood-flow fellby experiments, and the arteriovenous difference across the i.e., probably over half (Grayson and Lapin 1966, Rees and ischaemic zone of the dog heart increased with a mean Redding 1968). A similar shift from F.F.A. to glucose value of 19-30 mg. per 100 ml., fifteen to a hundred and utilisation can be inferred from the studies of Scheuer and twenty minutes after arterial occlusion. The arterial Brachfeld (1966) and Brachfeld and Scheuer (1967) who, glucose concentration was about 130 mg. per 100 ml. however, induced a graded reduction in coronary-artery throughout. The glucose concentration in blood from the blood-flow without total arterial occlusion. coronary sinus was constant, showing an unchanged The combination of increased glucose utilisation and glucose extraction by the non-ischaemic part of the lactate output suggests the occurrence of anaerobic heart. glycolysis in the ischsemic zone. Although it is well (iii) Serum-triglycerides.-These were measured in 7 recognised that the anaerobic breakdown of glucose to experiments. Once hydrolysed, the metabolism of tri- lactate yields only about a fifth of the energy obtained by glycerides by the heart follows the same pathways as those full aerobic combustion, nevertheless anaerobic metaboof F.F.A. derived from the circulation. Before and after lism can make a contribution substantial enough to ligation, the arteriovenous differences were small and maintain myocardial function in critical circumstances inconstant. Sometimes the venous samples exceeded the (Lochner et al. 1959). arterial values for short periods. Arterial occlusion seemed Decreased relative utilisation of F.F.A. by the ischaemic segment may be relevant to the pathophysiological problems of patients with acute myocardial infarction. In the acute phase, plasma-F.F.A. values are increased (Oliver et al. 1968), and a correlation between especially high values and the incidence of cardiac arrhythmias has been found. A suggested mechanism is that F.F.A. utilisation by the ischaemic heart-tissue may increase the myocardial oxygen consumption, thereby aggravating the ischaemia (Challoner and Steinberg 1966). However, this effect of F.F.A. was found in unphysiological circumstances, when F.F.A. was the sole substrate and the isolated hearts were not performing external mechanical work. Moreover, the Fig. 5-After arterial occlusion, arteriovenous difference of glucose effect was not very large and only occurred when the F.F.A. increases in the local vein but not in the coronary sinus. taken up could actually be oxidised. This last consideraValuess.E. of mean; P<0.05 at 15, 30, and 60 minutes after arterial occlusion. tion is of importance because oxidative breakdown of

Fig. 4-Arteriovenous differences between artery, local vein, and coronary sinus for plasma glucose and F.F.A.

1190 F.F.A. is, presumably, impaired in ischxmia. Nevertheless, in the absence of direct information on the fate of the F.F.A. uptake in terms of oxidation or storage as intracellular lipid (Evans 1964), it is not yet possible to relate decreased F.F.A. utilisation to oxygen uptake in the ischaemic area.

myocardial infarction the heart consists of a major fraction of non-ischaemic tissue, together with zones of varying ischaemia and infarction. In the non-ischaemic zone, F.F.A. is likely to be the major substrate both because the arterial concentration is high and because food intake is usually restricted in the early stages of myocardial infarction. In contrast, the ischaemic zone of the patient’s heart is more likely to depend on glucose as a major source of energy, although support may also be derived from cardiac glycogen stores (Jennings and Wartman 1957). It seems possible that glucose and glycogen, by conversion to lactate, can help meet the energy requirements of the ischaemic zone independently of the availability of oxygen; thereby the transition from ischsemia to death of the myocardial cell may be resisted. The multicentre Medical Research Council trial (1968) assessed the efficacy of therapy with glucose, potassium, and insulin in patients with acute myocardial infarction: there was no effect on life or death prognosis. However, the principles of the study were aligned towards reversal of potassium loss from the myocardium rather than towards increasing glucose utilisation by the heart. The present experimental observations suggest appraisal of the role of glucose utilisation in the earliest stages of myocardial infarction in man, and of the possible metabolic advantages of high plasma-glucose levels. In

patients

with

acute

We thank Prof. J. P. Shillingford and Prof. 1. D. P. Wooton for encouragement and support; Miss Susan Bailey, Mr. Peter Burgess, Miss Jean Powell, and also Mr. J. Robson and Mr. M. Cussen of the Department of Experimental Surgery, Royal Postgraduate Medical School, for technical assistance; and Dr. K. R. L. Mansford, of the Department of Biochemistry, Imperial College, London, for advice and help.

Requests for reprints should be addressed to M. T., M.R.C. Cardiovascular Research Unit, Royal Postgraduate Medical School, London W. 12. REFERENCES

Bing, R. J. (1954) Harvey Lecture Series, L; p. 27. New York. Brachfeld, N., Scheuer, J. (1967) Am. J. Physiol. 212, 603. Cascarano, J., Chick, W. L., Siedman, I. (1968) Proc. Soc. exp. Biol. Med. 127, 25. Challoner, D. R., Steinberg, D. (1966) Am. J. Physiol. 210, 280. Chlouverakis, C. (1963) Metabolism, 12, 936. Enser, M. B., Kunz, F., Borensztajn, J., Opie, L. H., Robinson, D. S. (1967) Biochem. J. 104, 306. Evans, J. R. (1964) Can. J. Biochem. 42, 955. Grayson, J., Lapin, B. A. (1966) Lancet, i, 1284. Harris, P., Jones, J. H., Bateman, M., Chlouverakis, C., Gloster, J. (1964) Clin. Sci. 26, 145. Horn, H. D., Bruns, F. H. (1956) Biochim. biophys. Acta, 21, 378. Jennings, R. B., Wartman, W. B. (1957) Med. Clins., N. Am. 41, 3. Lochner, W., Mercker, H., Nasseri, M. (1959) Nauryn-Schmiedebergs Arch. exp. Path. Pharmak. 236, 365. Mansford, K. R. L. (1968) PH.D. thesis; p. 165. University of London. Medical Research Council (1968) Lancet, ii, 1355. Mittra, B. (1965) ibid. ii, 607. Rees, J. R., Redding, V. J. (1968) Cardiovasc. Res. 2, 43. Oliver, M. F., Kurien, V. A., Greenwood, T. W. (1968) Lancet, i, 710. Sardesai, V. M., Manning, J. A. (1968) Clin. Chem. 14, 156. Scheuer, J. (1967) Am. J. Cardiol. 19, 385. — Brachfeld, N. (1966) Metabolism, 15, 945. Shipp, J. C., Opie, L. H., Challoner, D. (1961) Nature, Lond. 189, 1018.

Weissler, A. M., Kruger, F. A., Baba, N., Scarpelli, D. C., Leighton, R. F., Gallimore, J. K. (1968) J. clin. Invest. 47, 403.

THE HÆMORRHAGIC DIATHESIS OF HEATSTROKE

Consumption Coagulopathy Successfully Treated with Heparin

A

J. A. BLAKELY

M. B. WEBER

MEDICINE, NORTH YORK GENERAL AND SUNNYBROOK HOSPITALS, TORONTO 12, CANADA

FROM THE DEPARTMENTS OF

Heatstroke is sometimes

a severe

illness

Summary with neurological and hæmorrhagic mani-

probably due to consumption coagulopathy. patient with heatstroke, and with with consumption coaguloconsistent laboratory findings treated with heparin. has been successfully pathy, festations; the latter

are

A

Introduction

HEATSTROKE results when the heat-regulating mechanism of the hypothalamus fails and sweating ceases (Malamud et al. 1946, Austin and Berry 1956). Neurological disturbances are common. These include disorders of

consciousness, convulsions, tremors, ataxia, dysarthria,

flaccidity, Babinski signs, decorticate or decerebrate posturing, and pupillary abnormalities (Malamud et al. 1946, Gottschalk and Thomas 1966). The striking features of the brain at necrospy are oedema, congestion, and widespread petechial haemorrhages. Indeed, petechial haemorrhages are found in many organs including skin, lungs, heart, gastrointestinal tract, kidneys, pleurx, and conjunctivx (Malamud et al. 1946, Wilson 1940, Baxter and Teschan 1958, Wright et al. 1946, Shibolet et al. 1962, Gore and Isaacson 1949). This haemorrhagic state nas long been attributed to the increased capillary permeability (Wright 1946), hypoprothrombinxmia, and thrombocytopenia commonly observed (Malamud et al. 1946, Wilson and Doan 1940). It was not until 1962 that Shibolet et al. pointed out that hyponbrinogensmia and severe fibrinolysis occurred in heatstroke, and suggested that the cause of the hxmorrhagic state was fibrinolysis. Because no intravascular clots were found at necropsy, Shibolet believed that fibrinolysis was the primary event. This conclusion is not necessarily valid, since post-mortem examination of patients with intravascular coagulation and associated fibrinolysis from other causes often reveals no intravascular thrombi (Rosner and Ritz 1966). In view of recent knowledge of consumption coagulopathy (defibrination syndrome, diffuse intravascular coagulation), probably the thrombocytoperiia and prolonged prothrombin time are caused by primary intravascular coagulation with consumption of procoagulants ; and fibrinolysis and the hasmorrhagic diathesis are secondary phenomena (Verstraete et al. 1965). The patient described here had the clinical features of heatstroke; the laboratory findings were compatible with consumption coagulopathy, and the haemorrhagic state was successfully treated with heparin. Methods Blood was taken into 3-8% sodium citrate solution, 9 parts blood to 1 part citrate. The sample of July 20 was taken into an oxalate-containing Vacutainer’ and was assayed separately against a normal control sample similarly obtained. All samples were frozen as platelet-poor plasma and assayed

simultaneously. assayed in factor-v-deficient plasma (aged plasma). The patient’s plasma was used undiluted and in saline dilutions of 1/2, 1/4, and 1/8, and 0-02 ml. of Factor

E.D.T.A.

v

was