Secondary type II hyperlipoproteinemia in patients with anorexia nervosa

Secondary Type II Hyperlipoproteinemia in Patients With Anorexia Nervosa R. Mordosini, G. Klose, and H. Greten In 18 patients with anorexia nervosa, plasma cholesterol and triglyceride concentrations were repeatedly determined over a period of 14 mo. In 11 patients elevated cholesterol concentrations were found which were due to an increase of low-density lipoprotein cholesterol, whereas high-density lipoprotein and very low density lipoprotein cholesterol levels were in the normal range. The elevated cholesterol values did not correlate with clinical and laboratory parameters such as the degree of weight loss and thyroid

function tests. In follow-up studies it could be shown that in patients who regained their original weight, elevated plasma cholesterol concentrations fell to normal levels parallel to weight increase. In patients who showed no change in weight, however, cholesterol levels remained high. The cause for this secondary type II hyperlipoproteinemia in anorexia nervosa is not known. Hepatic triglyceride lipase and lipoprotein lipase activities in postheparin plasma were found to be low despite normal triglyceride concentrations.

D

URING THE PAST FEW YEARS, numerous studies on the metabolic changes in anorexia nervosa have been reported. Considerable weight loss, amenorrhea, hypotension, hypothermia, bradycardia, severe constipation, and low basal metabolic rate suggest an endocrine disorder in this complex striking changes in endocrine psychiatric disease. 3’-33*38In several studies, parameters were reported, especially low luteinizing hormone, follicle-stimulating hormone, and plasma growth hormone secretion. 1,4,10.12sl3.243 an addition, several authors found low or decreased serum triiodothyrodine (T3) and low serum thyroxine (T4) concentrations in patients with anorexia nervosa.‘0.27.28J0 Also reported were leukopenia in a large number of patients, electrocardiographic changes, disorders in intestine motility, and pathologic intestinal resorption.6*7q37 Klinefelter, in 1965, was the first to indicate increased cholesterol concentrations in the sera of patients with anorexia nervosa.” This finding was later confirmed by several authors. R*2g*38 Mainly nutritional factors7*’ or changes in cholesterol and bile acid turnover32 are discussed as causes of this metabolic disorder. The purpose of this study was to investigate the frequency, degree, and nature of lipid disorders in anorexia nervosa. Until now, no lipoprotein analyses in this disease had been performed. A number of recent reports reinforce the importance of accurate measurement of cu-lipoprotein cholesterol and B-lipoprotein cholesterol,26 as it has been realized that low levels of o-cholesterol and From the Klinisches Institut fir Herrinfarktforschung an der Medizinischen Universitiitsklinik Heidelberg, Heidelberg, Germany. Received for publication March 18, 1977. Supported by grants from the Schweizerischer Nationalfonds and the Deutsche Forschungsgemeinschaft (Sonderforschungsbereich 90. Cardiovasculiires System). Reprint requests should be addressed tq Dr. R. Mordasini, Klinisches lnstitut J&r Herzinfarktforschung an der Medizinisehen Universitiitsklinik Heidelberg. Bergheimer Str. 58, D-6900 Heidelberg. Germany. 0 I978 by Grune & Stratton, Inc. ISSN 0026-0495.0026-0495/78/2701-0009$0~.00/0

Met&Am,

Vol. 27, No. 1 (January), 1978

71

164.5

23.6

53.2

34.6

(kg)

Weight

LDL, low-density

162.8

(cm)

Height

22

(yr)

‘Abbreviotionr:

(n = 15)

(n=lB) Controls

Patients

subiws

Age

lipoprotein;

ml)

Serum

176zk34

348zt29

(ILJ)

Plasma Plasma

lOOzt24

194 l 19

Plasma

194 f

274 f

28

36

(mg/lOOml)

Phospholipids

LDL

115+14

lB5zt36

Chol

(m9/100

Chol, cholesterol; TG, triglycerides.

119*41

(mg/lOOml)

Triglycerides

265~34

(mg/lOOml)

Cholesterol

density lipoprotein;

Amylose

VLDL, very low

1.44+0.24

88zt20 lipoprotein;

1.15ztO.30

T3 @g/ml)

81 ztl8

(r$ml)

HDL, high-density

7.3ztO.6

82 zt8

(g/loo

6.6ztO.7

ml)

Total Protein

6

80 f

(mg/lOO

Blood Sugar

Fasting

Table 1. Clinical and labomtory Data of Patients With Anorexia Nervosa and Controls

19&7

24k8

TG

ml)

42&t

40+8

Chol

TG

ml)

16zt5

14+7

HDL (mg/lOO

VLDL

25zt6

3919

Chol

ml) TG

65+15

76~18

(mg/lOO

SECONDARY

TYPE

73

II HYPERLlPOPROTElNEMlA

elevated &cholesterol concentrations are associated with premature atherosclerosis. Thus, it was of special interest to investigate the distribution of the increased cholesterol concentration among the individual lipoprotein classes in patients with anorexia nervosa. These results were correlated with other endocrinologic and metabolic parameters. MATERIALS

AND METHODS

Patients The patients studied were 18 females with a mean age of 22 (16-36) yr. The average duration of the disease was 28 (1649) mo. The main clinical and laboratory parameters are summarized in Table 1. Mean weight loss was 14.8 (7.3-24.2) kg. Only patients who had had amenorrhea for at least 12 mo were considered in this study. The diagnosis of anorexia nervosa was in each case confirmed by psychiatric examination. Nine patients who showed only minimal changes in the manifestation of the disease during the observation period were regularly examined at intervals of 6-8 wk for a period of 14 mo. Five patients who were clinically defined as “cured” were examined again after 14-25 mo under hospitalization. One of these patients had born a healthy child in the meantime; the others had reached their normal weight, and in some menstruation had started again. A group of I5 healthy female subjects of comparable age served as controls. A summary of the main clinical and laboratory data of this control group is given in Table I.

Methods Cholesterol and triglycerides were determined as previously described;37 phospholipids were determined as described by Lowry et al.23 and Bloor.3 Lipoprotein electrophoresis on agaroseagar was performed as described by Greten et al.14 Plasma obtained from the patients or normal subjects who had fasted overnight was collected in O.Ol’AEDTA and stored at 4°C. Fractionations were begun within 48 hr of collections. Standard sequential preparative ultracentrifugation of the plasma was performed in a Spinco model L2 65B ultracentrifuge using a type Ti 50 rotor at densities of 1.006, 1.019, 1.063, and 1.21 g/ml. I6 Other blood tests were performed according to standard laboratory techniques. Lipoprotein lipase (LPL) and hepatic triglyceride lipase (H-TGL) were performed as described by Greten et al.‘s An immunochemical method was used for selective measurement of these two enzymes in postheparin plasma. All blood samples were drawn 10 min after intravenous injection of heparin, at 60 U/kg body weight in tubes containing a final EDTA concentration of 0.01%. Blood was immediately centrifuged at 4°C and plasma was removed. Enzyme determinations were performed within 48 hr. RESULTS

The results of the lipid determinations in whole serum and after isolation of the individual lipoprotein fractions by ultracentrifugation are summarized in Table 1. As compared to the control group, cholesterol and phospholipid levels in the patients under investigation were significantly increased (Fig. 1). Plasma triglyceride concentrations were also higher than those of the control group; this difference, however, was only small and not statistically significant. The most obvious difference was in cholesterol levels. The mean serum cholesterol concentration in patients with anorexia nervosa was 265 mg/lOO ml, a value that is not only markedly increased as compared to a mean of 194 mg/lOO ml in the control group, but is also above the upper normal limit of approximately 230 mg/lOO ml. Phospholipid concentrations were in the upper normal range. The increase in total cholesterol was due to an increase of the cholesterol transported in the low-density lipoproteins (LDL), the &lipoproteins. Cholesterol concentrations in the high-density lipoproteins as well as in the very low density

MORDASINI,

74

KLOSE,

AND GRETEN

CKXESTEROL

300

7

,200 ii P 100

0 P LDL

NS

~OLxw5

150

I 7

IO0 F

50

a P awO5

P
VLOL

- CHOL

- CHOL

100

100

200

i \

HDL

- CHOL

50

PcOiW25

NS

n D N = lb

patients

normal controls

Fig. 1. Plasma lipid concholesterol centrations and determinations in individual lipoprotein fractions in patients with anorexia nervosa as compared to the control group.

lipoproteins were within the normal range (Fig. 1). With an average of 185 mg/ 100 ml in all cases, &cholesterol levels were also increased in comparison to the upper normal limit of the corresponding age class. The increase in the p-lipoprotein fraction was confirmed by lipoprotein electrophoresis. The incidence rate of hypercholesterolemia in the patients was approximately 60%. In four patients, LPL and H-TGL were determined in postheparin plasma by selective enzyme antibody precipitation. Mean values for H-TGL were 9.5 pmoles free fatty acid/ml/hr (normal range 15-40 pmoles/ml), and for LPL 4.4 rmoles free fatty acid/ml/hr (normal range 5-15 ccmoles/ml). Glucose concentrations of the patients with anorexia nervosa were normal. Total protein was slightly decreased as compared to the control group, but it remained, on the average, within the normal range. T4 values were found to be normal with one exception. Three patients had decreased T3 values. As compared to the healthy subjects, mean T, values were decreased slightly, but not

SECONDARY

TYPE II HYPERLIPOPROTEINEMIA

75

80

1.6

60

1.2

40

08

--

0.4

20

Fig. 2. (A) Thyroxine (1,) and (B) triiodothyrodine (1s) concentrations (pg/ml) in patients with anorexia nenosa as compared to those in normal controls (--, normal range).

0

0

I

MS

m pllimh 0

mmd

PCO.am

cmlrds

N’ld

statistically significant. A significant difference, however, was found in T3 values, which were lower in the patients than in the control group (Fig. 2). In nine patients, increased amylase levels were found; there were, however, no clinical signs of pancreatitis. The degree of hypercholesterolemia in patients with anorexia nervosa was neither dependent on the absolute weight loss nor on the percentage deviation from the required minimal weight. There was also no evidence of a correlation between T3 and T., values and the degree of cholesterol increase. A relation between serum cholesterol and serum amylase, which was frequently increased, could not be found either. In the nine patients who could be controlled regularly during a period of 14

1oc

0

A

N=9

300

.M

zffi 40

100

B 0

30

N=S I

2

3

4

5 6 mmlhs

7

8

9

10

1,

Fig. 3. Cholesterol concentrations and body weight during 1 yr of observation. (A) Nine patients with no increase in body weight and no change in cholesterol concentration. a, cholesterol; A, weight. (B) Five patients who regained their original weights with a concomitant decrease of cholesterol concentration. o, cholesterol; l, weight.

MORDASINI,

300

3oc

200

200

100

100

KLOSE,

AND GRETEN

F B ‘e

0

0 p m25

P (4025

NS

pto.01

Fig. 4. (A) Total cholesterol and (B) &cholesterol in five patients with anorexia before treatment and after recovery of weight loss as compared to normal subjects.

nervosa

mo and who showed only small changes in the manifestation of the disease, hypercholesterolemia remained without major changes. In the five patients who regained their original weight and whose menstrual period had begun again, a marked decrease of serum cholesterol levels was found during the observation period of 14 mo (Fig. 3). At the same time, P-cholesterol levels fell to nearly normal values. As compared to the values of the control group, total cholesterol and @-cholesterol were only minimally increased in these patients after regaining their original weight. This difference was no longer significant for total cholesterol. In &cholesterol, however, the difference after a marked decrease was still significant (Fig. 4). DISCUSSION

In 11 of 18 patients with confirmed anorexia nervosa, hyperlipoproteinemia with a type II pattern was found. The increased plasma cholesterol levels were due to an increase of cholesterol transported in the P-lipoproteins. Triglyceride as well as phospholipid concentrations were found in the upper normal range. The cause for this hypercholesterolemia in patients with anorexia nervosa has 7*8~‘8*38 A long-term hypocaloric diet is usually followed not yet been elucidated. fractions. 21.22.35 The decrease of serum choby a decrease of all lipoprotein lesterol, however, is only small, and it is delayed as compared to the other serum lipids. Some authors, however, have observed a temporary increase of the LDL fraction in fasting.39 The considerable degree of hypercholesterolemia found in the patients with anorexia nervosa can hardly be explained by a hypocaloric metabolic situation alone. The question of nutritional influences is most difficult to answer, as the intake of the administered diet is doubtful and hard to control in these patients. At the time of first examination, the diet in our cases of anorexia nervosa

SECONDARY

TYPE

II HYPERLIPOPROTEINEMIA

77

was, however, most probably rich in carbohydrates, low in fat, and certainly hypocaloric. During the hospitalization of patients who were given isocaloric tube feeding (consisting of 40% carbohydrates and polyunsaturated fat, respectively, and of 20% protein), hypercholesterolemia was observed to be unchanged. Therefore, nutritional influences can be assumed to play no major role in the development of hypercholesterolemia in anorexia nervosa, although this hypothesis is suggested by some authors.‘v8 Hypothyroidism can be excluded as the explanation for the increased cholesterol levels according to our results. An interesting observation is the decreased sterol and bile acid secretion in the stool of a small number of patients with anorexia nervosa and hypercholesterolemia.29 These results suggest a diminished cholesterol turnover, which could be due to delayed LDL catabolism. This assumption is supported by the fact that numerous metabolic processes, such as thermoregulation, are reduced in anorexia nervosa. As a result, type IIa hyperlipoproteinemia in these patients would be due to delayed LDL catabolism. Another explanation, however, seems to be more probable: the observed increase of total and P-cholesterol concentration in plasma could be explained by the fact that the patients with anorexia nervosa lost substantial amounts of their body fat mass. Adipose tissue is known to contribute greatly to total body cholesterol, and therefore the dramatic mobilization of body fat as energy supply in the patients may lead to elevated plasma cholesterol levels. No evidence, however, could be found for increased LDL synthesis as the cause of hypercholesterolemia in anorexia nervosa. The normalization of cholesterol values at the improvement of anorexia nervosa with marked and steady increase in weight under thorough psychosomatic treatment is characteristic for a secondary form of hyperlipoproteinemia. The markedly decreased values for H-TGL and LPL found in four patients confirm recent results obtained in our laboratory. It has been shown that both H-TGL and LPL activity are low following hypocaloric diets and starvation.” In 9 of 18 patients, increased amylase values were found without clinical signs of pancreatitis; however, this increase was only moderate. Altered secretion of pancreatic enzyme under fasting conditions, however, has been reported by several authors.5*9,20*2’ A relation between elevated serum cholesterol concentrations and T4 and T3 values was not found either. While T4 concentrations in patients were not significantly different from those in the control group, T, concentrations were significantly decreased in patients with anorexia nervosa. Decreased T., levels, reported by many authors,27~28~38 could not be confirmed in our study. The discrepancy between normal T4 and low T3 values, however, has been shown previously.27~28A deficient peripheral deiodination of T4 is supposed to be the cause for this discrepancy. This finding, is not characteristic for anorexia nervosa, but is observed in long-lasting consuming diseases of various etiologies.30*36 Anorexia nervosa is, at present, generally considered a primarily psychogenous disease2*7~17~3’ with different endocrinologic disorders of probably diencephalic origin. ‘2,25Type II hyperlipoproteinemia in many of these patients is one more factor with unclear etiology in this complex disease.

78

MORDASINI,

KLOSE,

AND GRETEN

ACKNOWLEDGMENT We would like to thank

Eva Schlumpf

and Brigitte

Walter

for their valuable

technical

assistance.

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distribution and chemical composition of ultracentrifugally separated lipoproteins in human serum. J Clin Invest 34:134551353. 1955 17. Jullien P, G&riot C: L’anorexie mentale. Nouv Presse Med 3:1157-l 158, 1974 18. Klinefelter H: Hypercholesterolemia in anorexia nervosa. J Clin Endocrinol 25:15201521, 1965 19. Klose G, Augustin J. Schlierf G, et al: Effect of fasting and effect of different diets on the two post-heparin lipases. 4th Hungarian Atherosclerosis Conference, 1976 20. Kumar R, Banks P, George P. et al: Early recovery of exocrine pancreatic function in adult protein-caloric malnutrition. Gastroenterology 68: 1593-l 595. 1975 21. Lageder H. Aigner 0, Schlick W, et al: Absolutes Fasten als Therapie bei Patienten mit Diabetes und Hyperlipidamie. Wien Klin Wochenschr 85: l86- 192, 1973 22. Lisch H, Bolzano K, Herbst M, et al: Effect of body weight changes on plasma lipids in patients with primary hyperlipoproteinemia. Atherosclerosis 19:477-484, 1974 23. Lowry OH, Roberts NR. Leiner KY, et al: The quantitative histochemistry of brain. 1. Chemical methods. J Biol Chem 207:l. 1954 24. Lundberg P, Walinder J, Werner I, et al: Effects of thyrotrophin-releasing hormone on plasma levels of TSH, FSH and GH in anorexia nervosa. Eur J Clin Invest 2: 150, 1972 25. Mecklenburg R. Loriaux L, Thompson R, et al: Hypothalamic dysfunction in patients with anorexia nervosa. Medicine 53:147- 159. 1974 26. Miller GJ, Miller NE: Plasma highdensity-lipoprotein concentration and development of ischaemic heart disease. Lancet l:l619,1975 27. Miyai K, Yamamoto T. Azukizawa M. et al: Serum thyroid hormones and thyrotropin in anorexia nervosa. J Clin Endocrinol Metab 40:334-338, 1975 28. Moshang T. Parks J, Baker L, et al: Low serum triiodothyronine in patients with anorexia nervosa. J Clin Endocrinol Metab 40: 470-473, 1975 29. Nestel PS: Cholesterol metabolism in anorexia nervosa and hypercholesterolemia. J Clin Endocrinol Metab 38:325. 1974 30. Portney G, O’Brian J. Vagenakis A, et al: Abnormalities in triiodothyronine metabo-

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79

Liproproteid-Dichteklassen durch Hunger und kohlehydratreiche Diat. Acta Med Aust l:5560, 1974 36. Sullivan P, Bollinger J, Reichlin S: Selective deficiency of tissue triiodothyronine: A proposed mechanism of elevated free thyroxine in the euthyroid sick. J Clin Invest 52:83a, 1973 37. Technicon Clinical Method No 24, 1972. Technicon Instruments, Tarrytown, NY 38. Warren M, Vande Wiele R: Clinical and metabolic features of anorexia nervosa. Am J Obstet Gynecol 117:435-449, 1973 39. Wilson D, Lees R: Metabolic relationship among the plasma lipoproteins. J Clin Invest 51:1051, 1972