Insulin sensitivity in patients with anorexia nervosa and bulimia

Altered metabolism and lipodystrophy in the early B-cell factor 1-deficient mouse

We previously reported that mice deficient for the transcription factor early B-cell factor (Ebf1) exhibit markedly increased numbers of osteoblasts, bone formation rate, and serum osteocalcin, but the bone marrow of Ebf1(-/-) mice is also striking in its increased marrow adiposity. The purpose of this work was to analyze the metabolic phenotype that accompanies the altered bone morphology of Ebf1(-/-) mice. Whereas marrow adiposity was increased, deposition of white adipose tissue in other regions of the body was severely reduced (sc 40-50%, abdominally 80-85%). Brown adipose exhibited decreased lipid deposition. Subcutaneous and perigonadal white adipose tissue showed a decrease in mRNA transcripts for peroxisomal proliferator-activated receptor-gamma2 and CCAAT/enhancer-binding protein-beta in Ebf1(-/-) tissue compared with wild type. Circulating levels of leptin were decreased in Ebf1(-/-) animals compared with their littermate controls (down 65-95%), whereas adiponectin remained comparable after 2 wk of age. Serum analysis also found the Ebf1(-/-) animals were hypoglycemic and hypotriglyceridemic. After ip injection of insulin, the serum glucose levels in Ebf1(-/-) mice took longer to recover, and after a glucose challenge the Ebf1(-/-) animals reached serum glucose levels almost twice that of their wild-type counterparts. Measurement of circulating pancreatic hormones revealed normal or reduced insulin levels in the Ebf1(-/-) mice, whereas glucagon was significantly increased (up 1.7- to 8.5-fold). Metabolically the Ebf1(-/-) mice had increased O(2) consumption, CO(2) production, food and water intake, and activity. Markers for gluconeogenesis, however, were decreased in the Ebf1(-/-) mice compared with controls. In conclusion, the Ebf1-deficient animals exhibit defects in adipose tissue deposition with increased marrow adiposity and impaired glucose mobilization.

Incomplete restoration of the secretion of ghrelin and PYY compared to insulin after food ingestion following weight gain in anorexia nervosa

BACKGROUND

In humans, ghrelin has been found to stimulate appetite while PYY3-36 to reduce it; these orexigenic and anorexigenic peptides play significant roles in appetite control. We investigated pre- and postprandial responses of ghrelin and PYY in anorexia nervosa (AN) and the influence of weight gain.

METHODS

Plasma ghrelin, PYY3-36, glucose and insulin responses after ingestion of a 400 kcal standard meal were measured in 14 patients with restricting type of AN and 12 controls. The AN patients were evaluated before therapy and after inpatient therapy. Psychometry was performed by the use of Eating Disorders Inventory.

RESULTS

Ghrelin was suppressed during the meal test, while PYY3-36 was increased in all of the groups. Before therapy, AN patients had significantly increased levels of ghrelin and PYY3-36 compared to the control (P<0.01). After therapeutic intervention, as the nutritional status of AN patients improved, the secretion of these hormones were increased (P<0.05), but not normalized as in psychological testing. In contrast, insulin and glucose responses were normalized after inpatient therapy.

CONCLUSIONS

We found that both ghrelin and PYY3-36 increased in AN patients and these changes were not normalized in contrast to insulin after treatment. The increase in both orexigenic ghrelin and anorexigenic PYY3-36 may have a role in pathological eating behavior in AN.

Glucose tolerance predicts short-term refeeding outcome in females with anorexia nervosa

OBJECTIVE

Little is known about biologic predictors of refeeding outcome in anorexia nervosa (AN). Because nutritional status mirrors glucose metabolism during an oral glucose tolerance test (OGTT) in AN, this study investigated whether pretreatment glucose response patterns during the OGTT might be associated with refeeding progress in patients with AN.

METHODS

Sixty-four female patients with anorexia (33 restrictors and 31 binge/purgers) and 13 healthy control subjects underwent an OGTT before nutritional rehabilitation, including desensitization to fear of energy intake of 1000 to 1600 kcal/day. Patients were divided into flat-type responders, impaired glucose tolerance (IGT)-type responders, and normal-type glucose responders. Daily energy intake, weekly weight gain, and the duration of desensitization period were evaluated until the 12th week.

RESULTS

The patients with anorexia consisted of 20 flat-type, 21 IGT-type, and 23 normal- type responders. Normal-type responders required a shorter time to complete the desensitization period than other responders (p = .003 for restrictors, p < .001 for binge/purgers). In terms of refeeding progress, significant group effects for daily energy intake and weekly weight gain were evident in restrictors (p = .006, p = .028, respectively) and binge/purgers (p < .001, p = .003, respectively); normal-type responders showed good refeeding progress compared with other responders in both AN subtypes.

CONCLUSIONS

The present study found a close relationship between pretreatment glucose responses, therapeutic progress of desensitization to fear of energy intake, and refeeding progress in both AN subtypes. Our findings suggest that glucose tolerance may be a useful predictor of short-term refeeding outcome in this disorder.

Eating pattern and the effect of oral glucose on ghrelin and insulin secretion in patients with anorexia nervosa

OBJECTIVE

Ghrelin is thought to be involved in the regulation of eating behaviour and energy metabolism in acute and chronic feeding states. Circulating plasma ghrelin levels in healthy humans have been found to decrease significantly after oral glucose administration. Because it is suggested that eating behaviour may influence the secretion of ghrelin and insulin in anorexia nervosa (AN), we examined the effect of oral glucose on ghrelin and insulin secretion in subtypes of AN patients.

DESIGN AND PATIENTS

Twenty female AN patients and 10 age-matched female controls were subjects. The patients were subdivided into two subtypes based on eating behaviour as follows: 11 restricting type (AN-R), nine binge-eating and purging type (AN-BP). Subjects underwent an oral glucose tolerance test at 08.00 h. Blood was collected 0, 30, 60, 120 and 180 min after the glucose load.

RESULTS

Both AN-R and AN-BP had a significant increased basal ghrelin level (P < 0.01) and a significantly decreased basal insulin level (P < 0.05) as compared to controls. The time of the nadir of mean ghrelin in AN-BP (120 min, 58.1% of basal level, 204.9 +/- 34.3 pmol/l, mean +/- SEM) was delayed compared to controls (60 min, 60.2%, 74.3 +/- 7.9 pmol/l), and in the AN-R group it kept decreasing for 180 min (80.0%, 182.4 +/- 31.5 pmol/l). The peaks insulin levels in AN-BP (120 min, 319.3 +/- 88.8 pmol/l) and AN-R (180 min, 418.9 +/- 68.4 pmol/l) were also delayed as compared to controls (60 min, 509.2 +/- 88.8 pmol/l). The glucose level at 180 min in AN-R was significantly (P < 0.05) higher than in controls.

CONCLUSIONS

These findings suggest that differences in eating behaviour in AN may induce alterations in both ghrelin and insulin metabolism in the acute feeding state. Furthermore, metabolic changes in the restrictive eating pattern may be related to the pathophysiology of small quantitative meal intake in AN-R patients.

Opposite changes in circulating adiponectin in women with bulimia nervosa or binge eating disorder

Adiponectin is a recently discovered peripheral peptide that is secreted exclusively by differentiated adipocytes. It has been shown to enhance insulin sensitivity, control body weight, regulate lipid homeostasis, and prevent atherosclerosis. Dysregulation of both lipid and glucose metabolism and changes in body weight and body fat mass have been reported in bulimia nervosa (BN) and/or binge eating disorder (BED); hence, investigation of adiponectin secretion is of obvious interest in these eating disorders. To this purpose, we measured plasma levels of adiponectin, glucose, cholesterol, triglycerides, and thyroid hormones in 60 drug-free women, including 20 patients with BN, 20 patients with BED, and 20 healthy controls. Compared with healthy women, BN women exhibited significantly increased circulating adiponectin levels (P < 0.002) and cholesterol concentrations (P < 0.005), whereas BED women had significantly reduced plasma levels of adiponectin (P < 0.005) and increased concentrations of glucose (P < 0.01), cholesterol (P < 0.05), and triglycerides (P < 0.02). Moreover, plasma levels of adiponectin were significantly correlated to the frequency of binge/vomiting episodes (r = 0.65, P = 0.002) in bulimics but not to the frequency of bingeing in BED patients. Because we did not include a group of obese patients who did not binge eat, the specificity of our findings in the BED should be considered cautiously. However, on the basis of present results, it is tempting to speculate that the increased production of adiponectin in BN may represent a compensatory mechanism to counteract the possible development of insulin resistance, whereas the decreased secretion of adiponectin in individuals with BED may be a risk factor for the development of glucose intolerance.

A characteristic reactive hypoglycemia induced by rapid change of eating behavior in anorexia nervosa: a case report

The relationship among reactive hypoglycemia, corresponding insulin metabolism, and eating behavior in anorexia nervosa (AN) has not been well documented.

METHOD

A 22-year-old woman with AN was admitted to Kagoshima University Hospital. An oral glucose tolerance test was performed with additional sampling at 15 minutes on the seventh hospital day when her daily caloric intake rapidly increased, reaching 2,000kcal perday.

RESULTS

An elevated level of insulin secretion (1,190pmol/L) was observed during the very early phase (15 minutes) after glucose load, whereas corresponding blood glucose elevations were not as high (1.2mmol/L). The patient experienced asymptomatic hypoglycemia (2.1mmol/L).

CONCLUSIONS

Our findings suggested that a rapid increase of energy intake might cause reactive hypoglycemia with characteristic insulin metabolism, that is, an elevated level of insulin secretion during the very early phase.

Insulinogenic index at 15 min as a marker of nutritional rehabilitation in anorexia nervosa

BACKGROUND

Insulin responses to the oral-glucose-tolerance test (OGTT) in anorexia nervosa (AN) are related to body weight and show various patterns. Although weight gain is a key indicator of a successful nutritional program, it is not a sufficiently accurate index for assessing nutritional status, especially in the periods of marked fear of obesity, because patients often manipulate body weight measurements.

OBJECTIVE

The aim of this study was to determine the relation between insulin metabolism during the early phase of the OGTT and progress (weekly weight gain) during nutritional rehabilitation.

DESIGN

Forty-eight inpatients with AN (25 AN restricting type and 23 AN bulimic type) underwent the OGTT, with additional blood sampling at 15 min, when energy intake reached 6694 kJ/d (1600 kcal/d). Thirteen healthy volunteers were also studied. To evaluate early-phase insulin metabolism, we calculated the insulinogenic index after 15 (II(15 min)) and 30 min. On the basis of weekly changes in body weight, the AN participants were divided into good (> or =0.5 kg) and poor (<0.5 kg) responders.

RESULTS

Among the AN patients, 48% were poor responders. Analysis of variance showed significant differences in the II(15 min) values (P = 0.0005) and showed that II(15 min) values for good responders were significantly higher than those for the other groups.

CONCLUSIONS

These findings suggest that a lack of progress in weight gain is frequently observed in AN and that II(15 min) values may be a useful marker with which to assess the weekly progress during nutritional rehabilitation.

The effect of bulimia nervosa on plasma glucose and lipids

This analysis examined changes in plasma lipids and glucose after 3 years in women treated for bulimia nervosa (BN). One hundred and thirty-five women aged 17-45 years with DSM-III-R BN entered a 12-week cognitive behavioral therapy treatment programme. Prior to and 3 years after treatment, patients completed psychiatric and behavioral assessments and fasting blood samples were drawn. At 3-year follow-up, 105 women were available, 67.6% of whom had no eating disorder and 32.4% of whom had any eating disorder (16.2% with eating disorder not otherwise specified and 16.2% with BN). Women with no eating disorder diagnosis at 3-year follow-up experienced a significant mean decrease in plasma glucose from pretreatment to 3-year follow-up compared to those with any eating disorder diagnosis. Eating disorder diagnosis at 3-year follow-up was independently associated with change in plasma glucose when potential confounders were adjusted for. Plasma triglyceride concentrations did not change in the group as a whole. Plasma HDL-cholesterol increased and total cholesterol decreased significantly from pretreatment to 3-year follow-up in the group as a whole. The decrease in serum cholesterol was significant in women with no eating disorder, but not in the women with any eating disorder diagnosis at 3-year follow-up. We conclude that a protracted course of BN may result in clinically insignificant increases in glucose concentrations and may attenuate the decrease in total cholesterol that is observed in women who recover from BN.

Menstrual cycle irregularity in bulimia nervosa. Associated factors and changes with treatment

OBJECTIVES

This study determined the clinical and nutritional variables associated with menstrual disturbance in women with bulimia nervosa (BN).

METHODS

Eighty-two women with DSM-IV BN underwent psychiatric, nutritional and menstrual related assessments prior to an outpatient treatment programme and at 12 months follow-up.

RESULTS

Forty-five percent reported a current irregular menstrual cycle. A high frequency of vomiting, low thyroxine concentrations and low dietary fat intake were independently associated with irregular menses at pretreatment. At 12 months follow-up, 30.5% reported irregular menstrual cycles. A greater difference between past maximum and minimum body weight, smoking and depression were associated with menstrual irregularity at 12 months follow-up. Of those with irregular menstrual cycles at pretreatment, 56.8% became regular at 12 months follow-up.

CONCLUSION

Menstrual irregularity in BN is associated with indices of nutritional restriction that are not reflected by low body weight or energy intake. Depression, cigarette smoking and fluctuations in body weight may act as metabolic stresses that contribute to the perpetuation of menstrual disturbances.

Plasma leptin levels, insulin secretion, clearance and action on glucose metabolism in anorexia nervosa

From a metabolic point of view, anorexia nervosa may be viewed as a mirror image of obesity. We compared insulin secretion, clearance and action on glucose metabolism during an intravenous glucose tolerance test in nine women with anorexia nervosa and in nine age-matched normal-weight controls. Insulin secretion (ISR) was derived by deconvolution of plasma C-peptide levels, insulin clearance (MCR(I)) was obtained by dividing the area under the curve (AUC(0-180 min)) of ISR by the corresponding AUC of plasma insulin levels, insulin sensitivity (S(I)) and glucose effectiveness index (S(G)) were calculated by Bergman's minimal model. The anorectic women had markedly lower BMI values (13.7+/-0.6 vs 23.2+/-0.8 kg/m2, p<0.0001) and serum basal leptin levels (2.8+/-0.6 vs 8.9+/-1.8 ng/mL, p=0.005) than control women. The anorectic women exhibited clear-cut lower fasting and post-glucose plasma insulin levels but similar corresponding plasma C-peptide concentrations when compared to controls. Consequently, ISR was similar in both groups while MCR(I) was significantly increased in anorexia nervosa (MCR(I): 3320+/-881 vs 822+/-79 mL x min(-1) x m(-2), p<0.02). The index S(I) tended to be higher in anorectic women than in normal-weight subjects, but without reaching the level of statistical significance because of a high between-subject variability (20.2+/-5.7 vs 12.5+/-2.2 10(-5) x min(-1)/pmol x L(-1), NS). The index S(G) was similar in both groups (0.022+/-0.004 vs 0.018+/-0.002 min(-1), NS). In conclusion, low plasma insulin levels observed in women with anorexia nervosa result from high MCR(I) rather than from depressed insulin secretion. Insulin sensitivity is not systematically increased and glucose effectiveness is unchanged in anorectic women when compared to normal-weight controls.

Insulin response in bulimia nervosa as a marker of nutritional depletion

OBJECTIVE

The aim of this provocation study was to examine insulin, glucose, and cortisol levels in response to a glucose load in bulimia nervosa patients and to relate this to behavior, treatment status, and depressive symptomatology.

METHOD

A 3-hr glucose tolerance test was performed in 15 female patients and in 4 controls. Tests were performed at different stages of treatment and following documented engagement in the patient's usual or previous repertoire of bulimic behaviors in the 24 hr prior to testing. Insulin, glucose, and cortisol levels were assayed at baseline and at 30-min intervals following the glucose load. Presence or absence of significant depressive symptomatology was ascertained.

RESULTS

Three patterns of insulin response were identified: (1) an exaggerated response, (2) a normative response which resembled that of healthy controls, and (3) a blunted pattern. A reciprocal relationship between peak insulin and mean cortisol levels was seen with higher depression scores associated with blunted insulin response. Patients whose response was exaggerated binged and vomited relatively infrequently and were of stable weight. The insulin response of successfully treated patients, abstinent from binging and vomiting for 4 weeks, was similar to that of normal controls. A blunted response occurred in patients who binged and vomited more frequently, whose weight was unstable, and whose baseline eating was chaotic or nonexistent.

DISCUSSION

The exaggerated insulin response was seen as a physiological adaptation to intermittent starvation reversible with treatment, while the blunted insulin response associated with higher cortisol levels was seen to result from more constant nutritional deprivation secondary to greater disturbance of behavior.

Carbohydrate metabolism and its regulatory hormones in anorexia nervosa

Findings of studies of carbohydrate metabolism in anorexia nervosa are reviewed. Topics covered included fasting blood sugar concentrations; serum insulin concentrations, insulin receptor binding activity, insulin sensitivity, and insulin resistance; plasma ketone bodies and free fatty acids; glucose tolerance tests; growth hormone, cortisol, intestinal hormones, and norepinephrine. Metabolic changes reported in anorexia nervosa are similar to those found in human and animal studies of states of caloric and carbohydrate restriction. Restoration of normal body weight is associated with normalization of virtually all measures. It is concluded that published studies offer no conclusive evidence for a syndrome-specific impairment in carbohydrate metabolism in anorexia nervosa.

Plasma amino acid ratios related to brain serotonin synthesis in response to food intake in bulimia nervosa

Fifteen bulimic women (BN) and 19 healthy female controls (CO) were studied. The subjects were cross-over treated with either fluoxetine (FXT) or placebo during 4 days. They received, in randomized order, a breakfast containing pure carbohydrate (CHO) or a protein-rich (PROT) breakfast following day 3 and 4 of each treatment period. Twenty-nine different food items were offered for lunch. The fasting serum glucose and insulin concentrations and the fasting plasma tryptophan (Trp)/large neutral amino acid (LNAA) ratio were slightly higher in BN. The changes of these metabolic parameters in response to a CHO or PROT breakfast were similar in both groups. Across breakfast type, the plasma (Trp)/(LNAA) ratio at 120 min after breakfast was higher in BN. Total caloric intake at lunchtime was less in BN. In CO, less carbohydrate was selected at lunchtime following the CHO breakfast, an effect that was abolished by FXT. Breakfast type or FXT did not have any apparent effect on food intake at lunchtime in BN. This might indicate that bulimic subjects are less sensitive to serotoninergic stimuli than control subjects.

Ovarian morphology and insulin sensitivity in women with bulimia nervosa

OBJECTIVE

Hyperinsulinaemia has a role in the development of hyperandrogenism and polycystic ovary syndrome in women of normal weight. Polycystic ovaries are common in women with bulimia nervosa and this study aimed to determine whether women with bulimia nervosa are insulin resistant and to examine the relation between insulin sensitivity and ovarian morphology.

DESIGN

A short intravenous insulin tolerance test was used as a direct measure of insulin sensitivity in a group of women with bulimia nervosa and a control group.

PATIENTS

A series of 12 women with bulimia nervosa and normal weight was compared with a control group of 9 healthy women who had no clinical signs of eating disorder or hyperandrogenism and did not have polycystic ovaries.

MEASUREMENTS

Bulimic behaviour was assessed using the BITE (Bulimia Investigation Test, Edinburgh) questionnaire and clinical interviews. Ovarian morphology was assessed using transabdominal ultrasonography. Insulin sensitivity and serum insulin, fasting glucose, LH, FSH, prolactin, testosterone, androstenedione and sex hormone binding globulin (SHBG) were measured and compared between the two groups.

RESULTS

Ten of the 12 women with bulimia nervosa underwent ovarian ultrasound examination and they all had polycystic ovaries. There was no difference in serum LH, FSH, testosterone, androstenedione of SHBG concentrations between the women with bulimia nervosa and the non-bulimic control group. Fasting blood glucose concentrations were normal in all the women studied and did not differ between the women with bulimia nervosa and the control women. There was also no difference in fasting serum insulin or insulin sensitivity between the women with bulimia nervosa and the nonbulimic women.

CONCLUSIONS

Bulimia nervosa is not associated with insulin resistance and chronic hyperinsulinaemia.