Low-dose glucocorticoid treatment affects multiple aspects of intermediary metabolism in healthy humans: a randomised controlled trial.

AIM/HYPOTHESIS: To assess whether low-dose glucocorticoid treatment induces adverse metabolic effects, as is evident for high glucocorticoid doses. METHODS: In a randomised placebo-controlled double-blind (participants and the investigators who performed the studies and assessed the outcomes were blinded) dose-response intervention study, 32 healthy men (age 22 ± 3 years; BMI 22.4 ± 1.7 kg/m(2)) were allocated to prednisolone 7.5 mg once daily (n = 12), prednisolone 30 mg once daily (n = 12), or placebo (n = 8) for 2 weeks using block randomisation. Main outcome measures were glucose, lipid and protein metabolism, measured by stable isotopes, before and at 2 weeks of treatment, in the fasted state and during a two-step hyperinsulinaemic clamp conducted in the Clinical Research Unit of the Academic Medical Centre, Amsterdam, the Netherlands RESULTS: Prednisolone, compared with placebo, dose dependently and significantly increased fasting plasma glucose levels, whereas only prednisolone 30 mg increased fasting insulin levels (29 ± 15 pmol/l). Prednisolone 7.5 mg and prednisolone 30 mg decreased the ability of insulin to suppress endogenous glucose production (by 17 ± 6% and 46 ± 7%, respectively, vs placebo). Peripheral glucose uptake was not reduced by prednisolone 7.5 mg, but was decreased by prednisolone 30 mg by 34 ± 6% (p < 0.0001). Compared with placebo, prednisolone treatment tended to decrease lipolysis in the fasted state (p = 0.062), but both prednisolone 7.5 mg and prednisolone 30 mg decreased insulin-mediated suppression of lipolysis by 11 ± 5% and 34 ± 6%, respectively. Finally, prednisolone treatment increased whole-body proteolysis during hyperinsulinaemia, which tended to be driven by prednisolone 30 mg (5 ± 2%; p = 0.06). No side effects were reported by the study participants. All participants completed the study and were analysed. CONCLUSIONS/INTERPRETATION: Not only at high doses but also at low doses, glucocorticoid therapy impaired intermediary metabolism by interfering with the metabolic actions of insulin on liver and adipose tissue. These data indicate that even low-dose glucocorticoids may impair glucose tolerance when administered chronically. TRIAL REGISTRATION: ISRCTN83991850.

Hepatic steatosis does not cause insulin resistance in people with familial hypobetalipoproteinaemia.

AIMS/HYPOTHESIS: Hepatic steatosis is strongly associated with hepatic and whole-body insulin resistance. It has proved difficult to determine whether hepatic steatosis itself is a direct cause of insulin resistance. In patients with familial hypobetalipoproteinaemia (FHBL), hepatic steatosis is a direct consequence of impaired hepatic VLDL excretion, independently of metabolic derangements. Thus, patients with FHBL provide a unique opportunity to investigate the relation between increased liver fat and insulin sensitivity. METHODS: We included seven male participants with FHBL and seven healthy matched controls. Intrahepatic triacylglycerol content and intramyocellular lipid content were measured using localised proton magnetic resonance spectroscopy (¹H-MRS). A two-step hyperinsulinaemic-euglycaemic clamp, using stable isotopes, was assessed to determine hepatic and peripheral insulin sensitivity. RESULTS: ¹H-MRS showed moderate to severe hepatic steatosis in patients with FHBL. Basal endogenous glucose production (EGP) and glucose levels did not differ between the two groups, whereas insulin levels tended to be higher in patients compared with controls. Insulin-mediated suppression of EGP during lower dose insulin infusion and insulin-mediated peripheral glucose uptake during higher dose insulin infusion were comparable between FHBL participants and controls. Baseline fatty acids and lipolysis (glycerol turnover) at baseline and during the clamp did not differ between groups. CONCLUSIONS/INTERPRETATION: In spite of moderate to severe hepatic steatosis, people with FHBL do not display a reduction in hepatic or peripheral insulin sensitivity compared with healthy matched controls. These results indicate that hepatic steatosis per se is not a causal factor leading to insulin resistance. TRIAL REGISTRATION: ISRCTN35161775.

High prevalence of diabetes mellitus in patients with liver cirrhosis.

AIMS: The reported prevalence of Type 2 diabetes mellitus in patients with liver cirrhosis is five times higher than in the general population. However, these data were never adjusted for classical risk factors for Type 2 diabetes. We therefore investigated the association between cirrhosis and Type 2 diabetes and adjusted for known risk factors for Type 2 diabetes. METHODS: We reviewed medical files for presence of Type 2 diabetes and potential confounders in 94 patients with cirrhosis (cases) and compared these with a control group of 107 patients with non-ulcer dyspepsia. Multiple logistic regression analysis was used to adjust for potential confounders. RESULTS: The aetiology of our cirrhosis population was alcohol (59%), viral hepatitis (10%), biliary cirrhosis (3%) or cryptogenic (28%). Prevalence of Type 2 diabetes was significantly higher in patients with cirrhosis than in control subjects: 35/94 (37%) vs. 7/107 (7%) (OR 8.5, 95% CI 3.5­20.2, P < 0.001). After adjustment for age, sex, family history of Type 2 diabetes, alcohol use and BMI, cirrhosis remained significantly associated with Type 2 diabetes (OR 13.6, 95% CI 4.3­42.9, P < 0.001). Most cases of Type 2 diabetes were already diagnosed before diagnosis of cirrhosis (21/35, 60%) or were incidentally found together with cirrhosis (5/35, 14%). CONCLUSIONS: Liver cirrhosis had a strong, independent association with Type 2 diabetes. Classical risk factors such as family history and BMI could not explain the high Type 2 diabetes prevalence in cirrhosis. Therefore, a liver-derived factor might aggravate glucose intolerance and cause Type 2 diabetes in cirrhosis. In addition, Type 2 diabetes might also cause cirrhosis through liver steatosis and fibrosis.

Whole-body resting and exercise-induced lipolysis in sarcopenic [corrected] patients with COPD.

Impaired beta-adrenoceptor-mediated lipolysis has been reported in sarcopenic [corrected] chronic obstructive pulmonary disease (COPD) patients. This could play a role in the shift in body composition towards decreased fat-free mass (FFM) and relative maintenance of fat mass (FM). Lipolysis could be affected by chronic treatment with beta(2)-agonists or disease-related factors. Therefore, whole-body resting and exercise-induced lipolysis were investigated in sarcopenic [corrected] COPD patients with moderate disease severity. Seven sarcopenic [corrected] COPD patients (mean+/-sem forced expiratory volume in one second (FEV(1)) 53+/-5% of the predicted value; body mass index (BMI) 27.5+/-0.9 kg x m(-2)) and seven controls matched for age, sex and BMI were studied. In addition, six underweight COPD patients (FEV(1) 51+/-5% pred; BMI 20.6+/-0.7 kg x m(-2)) matched for disease severity were recruited. Lipolysis and plasma levels of catecholamines were assessed during infusion of [(2)H(5)]glycerol at rest and during submaximal cycling exercise. The proportional FM was comparable between sarcopenic [corrected] patients and controls, whereas the FFM index was significantly reduced in patients. At rest, the rate of appearance (R(a)) of glycerol (4.1+/-0.6 and 3.3+/-0.2 micromol x kg FFM(-1) x min(-1), respectively) did not differ significantly. In underweight patients, glycerol R(a) (4.3+/-0.5 micromol x kg FFM(-1) x min(-1)) was also comparable. End-of-exercise lipolytic rates did not differ significantly between groups. Glycerol R(a) was not related to FM. Resting adrenalin levels were significantly increased in underweight COPD patients and were related to resting lipolysis. Sarcopenia [corrected] in chronic obstructive pulmonary disease patients with moderate disease severity is not characterised by an abnormal lipolytic rate. Altered regulation of muscle protein turnover seems to be the trigger in the body compositional shift observed in these patients.

Overweight, insulin resistance and type II diabetes in type I Gaucher disease patients in relation to enzyme replacement therapy.

Type I Gaucher disease, a lysosomal storage disorder is associated with metabolic abnormalities such as high resting energy expenditure, low circulating adiponectin and peripheral insulin resistance. Treatment with enzyme replacement therapy (enzyme therapy) leads to a decrease in resting energy expenditure, but its influence on weight and risk of development of type II diabetes is unknown. We studied the BMI, prevalence of overweight, insulin resistance and type II diabetes in untreated and enzyme therapy treated Gaucher patients before and after several years of follow-up and compared this to data on healthy subjects from literature. We established that in untreated Gaucher patients the prevalence of overweight is lower than in the general population. Long-term treatment with enzyme therapy induces a larger than average weight gain leading to a similar prevalence of overweight in enzyme therapy treated patients and the general population. The prevalence of type II diabetes increases significantly during treatment with enzyme therapy, resulting in a comparable prevalence of type II diabetes in enzyme therapy treated patients and the general population.

Effect of acute hyperglycaemia and/or hyperinsulinaemia on proinflammatory gene expression, cytokine production and neutrophil function in humans.

AIMS: Type 2 diabetes is frequently associated with infectious complications. Swift activation of leucocytes is important for an adequate immune response. We determined the selective effects of hyperglycaemia and hyperinsulinaemia on lipopolysaccharide (LPS)-induced proinflammatory gene expression and cytokine production in leucocytes and on neutrophil functions. METHODS: Six healthy humans were studied on four occasions for 6 h during: (i) lower insulinaemic euglycaemic clamp, (ii) lower insulinaemic hyperglycaemic clamp, (iii) hyperinsulinaemic euglycaemic clamp, and (iv) hyperinsulinaemic hyperglycaemic clamp. Target levels of plasma glucose were 12.0 mmol/l (hyperglycaemic clamps) or 5.0 mmol/l (euglycaemic clamps). Target plasma insulin levels were 400 pmol/l (hyperinsulinaemic clamps) or 100 pmol/l (lower insulinaemic clamps). RESULTS: Hyperglycaemia reduced LPS-induced mRNA expression of nuclear factor of kappa light polypeptide gene enhancer in B cells inhibitor alpha (NFKBIA), interleukin-1 alpha (IL1A) and chemokine (C-C motif) ligand 3 (CCL3), whereas during hyperinsulinaemia enhanced mRNA levels occurred in six out of eight measured inflammation-related genes, irrespective of plasma glucose levels. Combined hyperglycaemia and hyperinsulinaemia led to enhanced IL1A, interleukin-1 beta (IL1B) and CCL3 mRNA levels upon LPS stimulation. Neither hyperglycaemia nor hyperinsulinaemia altered cytokine protein production, neutrophil migration, phagocytic capacity or oxidative burst activity. CONCLUSIONS: These results suggest that short-term hyperglycaemia and hyperinsulinaemia influence the expression of several inflammatory genes in an opposite direction, that the acute effects of hyperinsulinaemia on inflammatory mRNA levels may be stronger than those of hyperglycaemia, and that the effects of insulin, in particular, may be relevant in the concurrent presence of hyperglycaemia.

Plasma insulin concentrations during a hyperinsulinaemic clamp: what do we measure?

BACKGROUND: The aim of this study is to compare the performance of three commonly used insulin assays with respect to the detection of exogenous human and porcine insulin added to human or rat plasma. METHODS: The DPC Immulite human insulin assay, the Mercodia rat insulin enzyme-linked immunosorbent assay and the Linco rat insulin radioimmunoassay were tested. RESULTS: The mean cross-reactivity of exogenous insulin ranged from 25% to 92%. The mean cross-reactivity of Actrapid in human plasma on the DPC Immulite was 56% and was independent of the endogenous insulin concentration. CONCLUSIONS: The measurement of exogenous insulin varies according to the source of exogenous insulin, matrix and insulin assay.

Short-term manipulation of plasma free fatty acids does not change skeletal muscle concentrations of ceramide and glucosylceramide in lean and overweight subjects.

CONTEXT: Increased plasma free fatty acid (FFA) concentrations may be in part responsible for the increased levels of ceramide in skeletal muscle of obese subjects. OBJECTIVE: We studied the effect of lowering and increasing plasma FFA levels on muscle ceramide and glucosylceramide concentrations in lean and obese subjects. DESIGN: Plasma FFAs were either increased or decreased for 6 h by infusing a lipid emulsion or using Acipimox, respectively. Muscle biopsies were performed before and after the intervention for measurements of ceramide and glucosylceramide. STUDY SUBJECTS: Eight lean [body mass index 21.9 (range, 19.6-24.6) kg/m2] and six overweight/obese [body mass index 34.4 (27.8-42.5) kg/m2] subjects without type 2 diabetes mellitus participated in the study. MAIN OUTCOME MEASURE: Differences in muscle ceramide and glucosylceramide upon manipulation of plasma FFAs were measured. RESULTS: There were no differences in muscle ceramide and glucosylceramide between lean and obese subjects, respectively. Increasing or decreasing plasma FFAs for 6 h had no effect on ceramide [high FFAs: 24 (19-25) vs. 24 (22-27) pmol/mg muscle, P=0.46; and 22 (20-28) vs. 24 (18-26) pmol/mg muscle, P=0.89 in lean and obese, respectively; low FFAs: 26 (24-35) vs. 23 (18-27) pmol/mg muscle, P=0.17 and 24 (15-44) vs. 24 (19-42) pmol/mg muscle, P=0.6 in lean and obese, respectively] and glucosylceramide [high FFAs: 2.0 (1.7-4.3) vs. 3.4 (2.1-4.6) pmol/mg muscle, P=0.17; and 3.0 (1.3-6.7) vs. 2.6 (1.2-3.9) pmol/mg muscle, P=0.89 in lean and obese, respectively; low FFAs: 2.2 (1.0-4.4) vs. 1.7 (1.4-3.0) pmol/mg muscle, P=0.92; and 6.6 (1.0-25.0) vs. 4.3 (1.3-7.6) pmol/mg muscle, P=0.7 in lean and obese, respectively] concentrations in skeletal muscle. CONCLUSION: Short-term manipulation of plasma FFAs has no effect on ceramide and glucosylceramide concentrations in skeletal muscle from lean and obese subjects.

Perspective: How to evaluate studies on peri-operative nutrition? Considerations about the definition of optimal nutrition for patients and its key role in the comparison of the results of studies on nutritional intervention.

Different nutritional outcome studies on the same subject can have vast differences in composition of the chosen food without justification, suggesting that the composition of "optimal" nutrition in patients is not known or that optimal nutrition does not exist. The result will be negative studies which reinforces the existing impression that nutritional intervention is of limited value in every day's patient care. This perspective will put arguments forward that optimal nutrition exists and that the definition of optimal nutrition should be the base of future nutrition intervention studies. This perspective aims at providing a definition of optimal nutrition and consequently a basis to critically appraise the literature upon nutritional interventions in disease states.

[Treatment of intestinal failure in adults. I. Dietary measures]. / De behandeling van darmfalen bij volwassenen. I. Dieetmaatregelen.

Patients with intestinal failure, predominantly caused by short-bowel syndrome, have impaired quality of life due to the frequent development of complications. Dietary modifications have an established role in the treatment of short-bowel syndrome. Treatment of short-bowel syndrome includes optimising the balance of fluids and nutrients in the presence of reduced absorption. The population is heterogeneous due to differences in anatomical structure and the functional status of the remaining intestine. Diet must therefore be tailored to the individual patient. Determining the appropriate amount of carbohydrates is based on the presence of the colon, because carbohydrates are processed in the colon by bacterial fermentation. Patients with a jejunostomy rapidly become dehydrated because they lose more sodium and fluids than are taken up enterally. The jejunum rapidly absorbs solutions with high salt concentrations, such as the WHO-recommended oral rehydration solution. Replacement of long-chain fatty acids with water-soluble medium-chain fatty acids increases the energy intake in patients with short-bowel syndrome and a colon. Extra attention should be given to electrolytes, trace elements and vitamins. Patients with short-bowel syndrome and a colon are at risk for oxalate nephropathy. For these patients, a low oxalate diet is recommended. With these interventions, many patients with intestinal failure will ultimately become independent of total parenteral nutrition.

ESPEN Guidelines on Enteral Nutrition: Wasting in HIV and other chronic infectious diseases.

Undernutrition (wasting) is still frequent in patients infected with the human immunodeficiency virus (HIV), despite recent decreases in the prevalence of undernutrition in western countries (as opposed to developing countries) due to the use of highly active antiretroviral treatment. Undernutrition has been shown to have a negative prognostic effect independently of immunodeficiency and viral load. These guidelines are intended to give evidence-based recommendations for the use of enteral nutrition (EN) by means of oral nutritional supplements (ONS) and tube feeding (TF) in HIV-infected patients. They were developed by an interdisciplinary expert group in accordance with officially accepted standards and is based on all relevant publications since 1985. Nutritional therapy is indicated when significant weight loss (>5% in 3 months) or a significant loss of body cell mass (>5% in 3 months) has occurred, and should be considered when the body mass index (BMI) is <18.5 kg/m(2). If normal food intake including nutritional counselling and optimal use of ONS cannot achieve an adequate nutrient intake, TF with standard formulae is indicated. Due to conflicting results from studies investigating the impact of immune-modulating formulae, these are not generally recommended. The results obtained in HIV patients may be extrapolated to other chronic infectious diseases, in the absence of available data.

The prognostic value of severe malnutrition in the development of nonthyroidal illness in head and neck cancer patients.

BACKGROUND: Thyroid hormone metabolism is modulated by starvation and overfeeding but also by dietary composition. Unfortunately, little is known about the effect of malnutrition on disease-induced nonthyroidal illness (NTI). In this study, we investigated whether the degree of NTI after surgery differed between severely malnourished and well-fed patients with head and neck cancer. METHODS: Plasma levels of the thyroid hormones 3',5-triiodothyronine (T(3)), reverse T(3) (rT(3)), free T(4) (FT(4)), and thyrotropin (TSH) were measured on the first day before the operation and on the first, fourth, and seventh day after the operation in 16 malnourished patients who were admitted for intentional curative surgery of T1-T4 carcinomas of the head and neck. Six well-fed head and neck cancer patients eligible for surgical treatment served as a control group. RESULTS: In the malnourished group, rT(3) showed a significant increase, whereas T(3) and FT(4) decreased significantly due to the operation. TSH showed no significant change. During the postoperative course, it took 7 days until rT(3) and 4 days until T(3) and FT(4) were restored to their preoperative value. In contrast, well-fed patients did not develop NTI. CONCLUSIONS: This study shows that peri- and postoperative rT(3), T(3), and FT(4) levels change significantly in malnourished patients compared with well-fed patients. Therefore, it can be concluded that nutrition status of patients undergoing major head and neck surgery should be optimized in order to prevent the development of NTI.

The dysmetabolic syndrome: epidemiology and etiology.

The metabolic syndrome is a common metabolic disorder that results from the increasing prevalence of obesity. It also refers to a clustering of specific cardiovascular disease risk factors whose underlying pathophysiology is thought to be related to insulin resistance with an excessive flux of fatty acids implicated. Opinions have varied as to whether the metabolic syndrome should be defined to indicate mainly insulin resistance, the metabolic consequences of obesity, risk of cardiovascular disease, or simply a collection of statistically related factors. Based on these different viewpoints 4 definition sets of the metabolic syndrome are formulated. The pros and cons of each of them are extensively discussed. A major role in the etiology of the metabolic syndrome is ascribed to the occurrence of insulin resistance. Data are provided that insulin resistance can worsen the expression of this syndrome, but cannot have a primary role. Therefore, insulin resistance is not the main player of the metabolic syndrome, but central obesity is. Free fatty acid induced insulin resistance is found and induced by central obesity. The metabolic syndrome is a cluster of abnormalities in which each of them deserves its own (maximal) treatment to diminish the risk for cardiovascular disease.

[Bacteraemia in a patient with a central venous line is not a reason for immediate removal of the line]. / Bij bacteriëmie hoeft een diepe lijn niet meteen te worden verwijderd.

Fever and the presence of a central venous catheter is a frequent combination in (critically) ill patients, but has a low predictive value for catheter-related sepsis. Therefore, the immediate removal of a central venous line is often unnecessary, even if there is fear for endocarditis when Staphylococcus aureus is present. Recent studies have shown that the odds ratio for this complication is rather low.

HIV-associated adipose redistribution syndrome as a selective autonomic neuropathy.

Abnormal body-fat distribution in HIV-1-associated adipose redistribution syndrome (HARS) remains unexplained at present. White adipose tissue is controlled by humoral factors and by neural regulation. Sympathetic innervation stimulates lipolysis, whereas parasympathetic innervation has an anabolic influence on white adipose tissue. Results of neuroanatomical studies showed a clear somatotopy with respect to autonomic control of white adipose tissue by both the sympathetic and parasympathetic branch, with separate sets of autonomic neurons innervating either the subcutaneous or the visceral fat compartment. Thus, the CNS is likely to be a key player in regulation of body-fat distribution. We propose that HARS is mediated by effects of antiretroviral treatment on the CNS and could indicate a change in autonomic balance resulting in redistribution of adipose tissue.

[Treatment of intestinal failure by total parenteral nutrition at home in children and adults]. / De behandeling van darmfalen met parenterale thuisvoeding bij kinderen en volwassenen.

Intestinal failure is characterised by inability of the intestine to absorb sufficient nutrients to maintain the integrity and function of the body. This can be caused by malabsorption due to too short an intestine or an abnormality of the mucosa, or by a severe motility disorder. In addition to dietary measures, the prescription of total parental nutrition (TPN) at home is sometimes necessary. This treatment is a burden on the patient and the risk of complications must be reduced to a minimum. The risks of long-term parenteral nutrition can be limited and the quality of the provision of services can be increased if the co-ordination is in the hands of a centre for home parenteral nutrition. In the Netherlands there are two centres for home-TPN: the St Radboud University Medical Centre in Nijmegen and the University Medical Centre (AMC) in Amsterdam. In both children and adults, the most common indications are the short bowel syndrome and motility disorders. However, the syndromes that cause this are clearly different in the different age groups. Parenteral nutrition can be given for long periods of time. A large variety of complications can occur, related especially to the equipment or the nutrients. When the nutrition is given via a central venous catheter, then sepsis is a serious and possibly life-threatening complication. In case of administration via an arteriovenous shunt, thrombosis of the shunt is the most frequent problem. If the treatment by means of home-TPN fails, then transplantation of the small intestine should be considered.

Soluble receptors for tumour necrosis factor: a putative marker of disease progression in HIV infection.

OBJECTIVE: To assess the value of concentrations of soluble receptors for tumour necrosis factor (sTNFR) as markers for disease progression in HIV infection. DESIGN: We measured concentrations of sTNFR in the serum of 32 HIV-infected male patients in various stages of disease and in 12 healthy male control subjects. Correlations between the levels of sTNFR and CD4+ lymphocyte counts were calculated. RESULTS: Serum levels of sTNFR p55 and p75 were elevated in parallel with severity of clinical stage. sTNFR p55 levels were higher at later stages of HIV infection (Centers for Disease Control stage IV) with or without concurrent illness, whereas sTNFR p75 was already elevated in asymptomatic carriers, compared with controls. There was an inverse correlation between sTNFR concentrations and CD4+ lymphocyte counts. CONCLUSIONS: Our results suggest that sTNFR concentrations could be potential markers for disease progression in HIV infection.

Lipodystrophy in HIV-1-positive patients is associated with insulin resistance in multiple metabolic pathways.

BACKGROUND: Treatment for HIV-1 infection is complicated by fat redistribution (lipodystrophy). This is associated with insulin resistance concerning glucose uptake. Our aim was to characterize glucose metabolism more comprehensively in HIV-1-infected patients with lipodystrophy. We assessed glucose disposal and its pathways, glucose production, plasma free fatty acid (FFA) levels, and the degree to which these parameters could be suppressed by insulin. METHODS: Six HIV-1-infected men on protease inhibitor-based HAART with lipodystrophy (HIV+LD) were studied. The results were compared with those in six matched healthy male volunteers. Insulin sensitivity was quantified by hyperinsulinemic euglycaemic clamp. Glucose production and uptake were assessed by tracer dilution employing 6,6D(2)-glucose. RESULTS: At post-absorptive insulin concentrations, glucose production was 47% higher in HIV+LD than controls (P = 0.025). During clamp, glucose production was suppressed by 53% in HIV+LD, but by 85% in controls (P = 0.004). Glucose disposal increased in both groups, but by only 27% in HIV+LD versus 201% in controls (P = 0.004). Consequently, insulin-stimulated total glucose disposal was lower in HIV+LD patients (P = 0.006). Non-oxidative glucose disposal as percentage of total disposal did not differ significantly between groups (63% in HIV+LD and 62% in controls). Baseline plasma FFA concentrations were higher (0.60 versus 0.35 mmol/l; P = 0.024), whereas FFA decline during hyperinsulinemia was less (65 versus 85%; P = 0.01) in HIV+LD versus controls. CONCLUSIONS: Post-absorptive glucose production is increased in HIV-1-infected patients with lipodystrophy. Moreover, both the ability of insulin to suppress endogenous glucose production and lipolysis, and to stimulate peripheral glucose uptake and its metabolic pathways is reduced, indicating severe resistance concerning multiple effects of insulin.

The course of biochemical parameters of bone turnover during treatment with corticosteroids.

The mechanisms by which glucocorticoids cause osteopenia are incompletely understood. It is generally accepted that bone formation is depressed during corticosteroid treatment, but the cause of the ongoing bone resorption is less clear. Secondary hyperparathyroidism and changes in vitamin D metabolism are thought to play a role. This is based mostly on data from cross-sectional studies in heterogeneous patient groups. We, therefore, studied longitudinally the course of biochemical parameters and the hormones influencing bone turnover in a homogeneous group of 10 euthyroid patients with Graves' ophthalmopathy, all euthyroid for at least 1 yr before, during, and after a 12-week course of prednisone. Bone formation was depressed as reflected by a fall in serum osteocalcin (3.0 +/- 2.1, 1.7 +/- 1.1, and 2.4 +/- 1.9 micrograms/L at weeks 0, 4, and 12, respectively; P = 0.02) and in total alkaline phosphatase (1.15 +/- 0.33, 0.83 +/- 0.22, and 0.88 +/- 0.40 mukat/L; P = 0.001). Parameters of bone resorption (urinary hydroxyproline/creatinine ratio, serum acid phosphatase) and the levels of vitamin D metabolites remained unchanged. Serum intact PTH seemed to decrease slightly. Our findings suggest that glucocorticoid induced osteopenia is caused by a depressed bone formation in the presence of an unaltered but ongoing bone resorption. Secondary hyperparathyroidism and changes in vitamin D metabolism are apparently not involved.

Acute effects of interferon-alpha administration on thyroid hormone metabolism in healthy men.

Both hyper- and hypothyroidism have been reported during prolonged recombinant human interferon-alpha (rhIFN alpha) therapy. To assess the short term effects of IFN alpha therapy on thyroid hormone metabolism, we measured thyroid hormone concentrations in eight healthy volunteers for 24 h after sc administration of rhIFN alpha and, on another occasion, after sc administration of saline (control study). There were no effects of rhIFN alpha on plasma T4 and free T4 or on thyroid hormone binding index. However, rhIFN alpha induced a significant decrease in the plasma concentrations of TSH (P < 0.03) and T3 (P < 0.02) compared with those in the control study, associated with an increase in rT3 concentrations (P < 0.02). IFN alpha induced a moderate increase in interleukin-6 (IL-6) concentrations (P < 0.02 vs. control study), whereas IL-1 and tumor necrosis factor concentrations remained below the detection limit in all subjects. It is concluded that IFN alpha administration induces major changes in thyroid hormone metabolism, possibly mediated in part by IL-6. The acute effects of rhIFN alpha mimic the euthyroid sick syndrome and appear to be different from the effects of chronic rhIFN alpha treatment on thyroid hormone metabolism.