Levothyroxine absorption in health and disease, and new therapeutic perspectives

Levothyroxine therapy is used in case of deficiency of the thyroid hormones in the human organism. Many conditions, either physiological or paraphysiological or clearly pathological, can alter the levothyroxine absorption in the human body. Levothyroxine absorption can indeed be impaired by age, patient's compliance, fasting, the intake of certain foods (such as dietary fibers, grapes, soybeans, papaya and coffee) or by some drugs (such as proton-pump inhibitors, antacids, sucralfate, et cetera). Additionally, many gastrointestinal diseases, such as the conditions that disrupt the integrity of the intestinal barrier and the diseases that impair gastric acidity, may alter the bioavailability of levothyroxine. Since the enormous, widespread diffusion of thyroid diseases, a large number of patients have to face such issues. Therefore, the development of new levothyroxine oral formulations, other than solid tablets, may represent an interesting therapeutic approach, at the same time simple and effective, to face this problem. Recently, two different levothyroxine formulations have been proposed: the liquid formulation and the softgel formulation. Such formulations represent an innovative, effective and cheap therapeutic approach to hypothyroid patient with problems of impaired absorption of levothyroxine.

Primary Aldosteronism: Complete Remission after Adrenal Venography

A remission of adrenal adenoma producing aldosterone is described as a consequence of adrenal venous catheterization. The patient did not undergo surgery but she was kept on frequent clinical controls. The complete remission of the syndrome is still persisting three years after the incident. Since adrenal insufficiency is described after adrenal venous catheterization, the authors suggest that this procedure is to be restricted to well selected patients. When this incident occurs in pathological glands, a remission of endocrine syndrome may be expected.

Nonalcoholic fatty liver disease: defining a common problem

Non Alcoholic Fatty Liver Disease (NAFLD), with prevalence of 10-51% in general population involving all ages, is the major cause of elevation of ALT and a common finding by ultrasound screening and may range from simple steatosis, to Non Alcoholic Steatohepatitis (NASH) and its clinical consequences as cirrhosis and hepatocellular carcinoma. In this review will be analyse factors influencing the onset of the disease. NAFLD, primarly associated with insulin resistance, is in fact considered the hepatic manifestation of the metabolic syndrome: a cluster of disorder that includes obesity, diabetes mellitus, dyslipidaemia, arteriosclerosis and hypertension. The increased incidence and prevalence of obesity and diabetes may explain growing interest in NAFLD. Racial, ethnic, enviromental and behaviour models are also reviewed.

The natural history and risk factors for progression of non-alcoholic fatty liver disease and steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is a condition of increasing incidence in western Countries seldom associated to other diseases of high prevalence in general population (i.e. diabetes and obesity). NAFLD ranges from simple fatty liver to steatohepatitis (NASH), which may lead to cryptogenic cirrhosis and in some cases hepatocellular carcinoma (HCC). Natural history of NAFLD in humans is poorly understood and progression of liver disease seems to be due to interaction between hosting (i.e. genetic, gut flora, insulin resistance) and environmental factors (social and eating behaviours) that should be responsible of increased oxidative stress within hepatocytes. Even if we need non-invasive markers able to describe the progression of liver disease, only meaning of liver biopsy is useful to characterize the stigmata of worsening such as inflammation and fibrosis.

Fatty liver and drugs

Drug-induced liver diseases (DILD) are clinico-pathologic patterns of liver injury caused by drugs or other foreign compounds. Steatohepatitis is a rare form of DILD, and drugs account for fewer than 2% of non-alcoholic steatohepatitis (NASH). Drugs known to be capable of inducing steatosis and steatohepatitis can be divided into three broad groups: those that cause steatosis and steatohepatitis independently (e.g., amiodarone, perhexiline maleate); drugs which can precipitate latent NASH (e.g., tamoxifen); drugs whic duce sporadic events of steatosis/steatohepatitis (e.g., carbamazepine). Clinical DILD syndromes include acute viral hepatitis-like injury, acute liver failure, cholestatic hepatitis,liver disease with signs of hypersensitivity, autoimmune hepatitis-like injury, acute venous-Outflow obstruction, chronic cholestasis, ciirrhosis, steatosis and steatohepatitis. The clinical picture is by no means dependent on the mechanism of injury (direct hepatotoxicity, idiosyncratic reactions, hypersensitivity reactions). Reliable diagnosis of drug-induced liver disease requires demonstration of close correlation between the patient history and clinical, laboratory, and histological data.

Nutritional aspects in patients with non-alcoholic steatohepatitis (NASH)

BACKGROUND AND OBJECTIVES

Metabolic alterations are a common feature in patients affected by non-alcoholic steato-hepatitis (NASH). A strong correlation exists between overweight, in particular visceral fat accumulation, and prevalence of NASH, especially in men. Thus, diet-induced weight loss represents a fundamental tool in disease management of these patients. The aim of the present study was to evaluate body composition and nutrient utilisation in patients with NASH, comparing them with patients affected by chronic hepatitis related to hepatitis C virus (HCV) infection and with healthy subjects.

MATERIALS AND METHODS

Twenty male outpatients with NASH (age: 41 +/- 11 yr; BMI: 26.2 +/- 2.1 kg/m2) and 14 HCV male patients (age 44.6 +/- 13 yr; BMI: 24.8 +/- 2.8 kg/m2) were enrolled in the study. A group of 20 healthy male subjects (age: 39 +/- 10 yr; BMI: 23.3 +/- 1.1 kg/m2) were studied as controls. Body composition was assessed by anthropometry and dual-energy X-ray absorptiometry; resting metabolic rate and nutrient oxidation by indirect calorimetry. A 7-day food diary was collected. The main biochemical parameters were measured using standardised laboratory techniques.

RESULTS

Body weight was higher in NASH patients with respect to HCV patients and control subjects (respectively 75.2 +/- 8.9 vs 68.5 +/- 9.4 and vs 67.0 +/- 8.0 kg; P < 0.01) and this was essentially due to fat mass increase. Fat-free mass reduction was found in HCV patients with respect to both NASH and control subjects. Patients with NASH had a significantly higher waist circumference (P < 0.01) and a lower resting metabolic rate (RMR) with respect to HCV and control subjects. Energy intake was significantly higher in NASH patients (P < 0.01) compared to the other two groups.

CONCLUSIONS

NASH patients showed an increase in body weight, fat mass and visceral fat accumulation with respect to HCV and control subjects. The reduction in RMR, coupled with increase energy intake may explain the body composition alterations found in these patients.

Further lowering of muscle lipid oxidative capacity in obese subjects after biliopancreatic diversion

A reduced lipid oxidative capacity is considered a risk factor for the development of obesity, but a further impairment of lipid oxidative capacity is observed after weight loss. We aimed to define the mechanisms underlying this phenomenon in skeletal muscle and in particular to study the mitochondrial and peroxisomal lipid oxidative pathways. Thus we measured intramyocellular triglyceride content (IMTG) and the expression of genes of lipid oxidation [peroxisome proliferator-activated receptor-alpha, carnitine palmitoyltransferase 1B, and acyl-coenzyme A (acyl-CoA) oxidase 1] and synthesis (acetyl-CoA carboxylase B) using RT-PCR analysis in muscle biopsies of morbidly obese patients before and after biliopancreatic diversion. Weight reduction significantly decreased IMTG while increasing insulin sensitivity, measured by euglycemic hyperinsulinemic clamp. Moreover, an increase in glucose and a decline in lipid oxidation, as assessed by respiratory chamber, were observed. Weight loss reduced the expression of peroxisome proliferator-activated receptor-alpha (-46.7%), carnitine palmitoyltransferase 1B (-43.1%), acyl-CoA oxidase 1 (-37.8%), and acetyl-CoA carboxylase B (-48.7%). Our results indicate that a defect of both peroxisomal and mitochondrial oxidative pathways at the muscular level may contribute to the reduced fat oxidation in obese subjects after biliopancreatic diversion. They also suggest that a depression of the de novo lipogenesis may account for IMTG depletion.

V̇o2, V̇co2, and RQ in a respiratory chamber: accurate estimation based on a new mathematical model using the Kalman-Bucy method

A respiratory chamber is used for monitoring O2 consumption (V̇o2), CO2 production (V̇co2), and respiratory quotient (RQ) in humans, enabling long term (24-h) observation under free-living conditions. Computation of V̇o2 and V̇co2 is currently done by inversion of a mass balance equation, with no consideration of measurement errors and other uncertainties. To improve the accuracy of the results, a new mathematical model is suggested in the present study explicitly accounting for the presence of such uncertainties and error sources and enabling the use of optimal filtering methods. Experiments have been realized, injecting known gas quantities and estimating them using the proposed mathematical model and the Kalman-Bucy (KB) estimation method. The estimates obtained reproduce the known production rates much better than standard methods; in particular, the mean error when fitting the known production rates is 15.6 ± 0.9 vs. 186 ± 36 ml/min obtained using a conventional method. Experiments with 11 humans were carried out as well, where V̇o2 and V̇co2 were estimated. The variance of the estimation errors, produced by the KB method, appears relatively small and rapidly convergent. Spectral analysis is performed to assess the residual noise content in the estimates, revealing large improvement: 2.9 ± 0.8 vs. 3,440 ± 824 (ml/min)2 and 1.8 ± 0.5 vs. 2,057 ± 532 (ml/min)2, respectively, for V̇o2 and V̇co2 estimates. Consequently, the accuracy of the computed RQ is also highly improved (0.3 × 10-4 vs. 800 × 10-4). The presented study demonstrates the validity of the proposed model and the improvement in the results when using a KB estimation method to resolve it.

Intramyocitic lipid accumulation and SREBP-1c expression are related to insulin resistance and cardiovascular risk in morbid obesity

The aim of this study was to investigate the sterol regulatory element-binding protein 1c (SREBP1c) mRNA muscle expression in morbid obese subjects before and after massive lipid malabsorption due to bariatric surgery (bilio-pancreatic diversion, BPD). We studied 11 obese subjects (BMI 49+/-2 kg/m2) before and 24 months after BPD. Skeletal muscle SREBP1c mRNA expression was determined using RT-competitive PCR. Intramyocytic triglycerides were quantified by HPLC. Insulin sensitivity (M/I) was assessed by euglycemic-hyperinsulinemic clamp. Energy expenditure and respiratory quotient (RQ) were measured over 24 h in a calorimetric chamber. Total cardiovascular risk dropped from 2 before to -2.5 after BPD (P<0.0001). The M/I value was normalized after surgery (0.036+/-0.0148 to 0.095+/-0.0147 micromol kgFFM(-1) min(-1) pmoles(-1) P<0.001). SREBP-1c mRNA levels were decreased (from 4.12+/-2.43 to 2.69+/-1.83% of cyclophilin mRNA, P=0.02) after BPD. In a multiple regression analysis, M/I values (P<0.0001) as well as the intramyocytic triglyceride levels (P=0.039) were the most powerful independent variables for predicting cardiovascular risk. Our results show that the reduction of cardiovascular risk after bariatric massive weight loss is strongly related to the reversion of insulin resistance and to the lowering of intramyocytic triglyceride depots. These two parameters are associated with a significant reduction in SREBP-1c mRNA expression in skeletal muscle, suggesting that this transcription factor might be involved in the accumulation of triglycerides in muscle cells of morbidly obese subjects.

Effects of propionyl-L-carnitine topical irrigation in distal ulcerative colitis: a preliminary report

BACKGROUND/AIMS

To study the tolerability of propionyl-L-carnitine administered as rectal irrigation and its efficacy in improving the clinical picture of distal ulcerative colitis.

METHODOLOGY

Ten male subjects (aged 18 to 55 years, with a body mass index ranging from 21 to 25 Kg/m2) with distal ulcerative colitis were treated with propionyl-L-carnitine enemas (6 g in 200 mL physiological solution) twice a day over 120 minutes each. All subjects had a disease activity index from 0 to 1. A clinical, laboratory, endoscopy and biopsy evaluation was performed at baseline and 14 days after treatment. Serum tumor necrosis factor-alpha and interleukin-2 concentration was measured.

RESULTS

No side effects were reported by the entire patient population and the clinical conditions remained constant throughout the study period. The disease activity index improved significantly between the beginning and the end of the study in 80% of the patients. Histologic features (mucosal erosion, distortion of crypt architecture, inflammation and lamina propria gap) significantly improved in all treated patients. Serum interleukin-2 levels did not change significantly after propionyl-L-carnitine treatment (respectively: 14.7 +/- 15.8 before vs. 9.9 +/- 13.2 pg/mL), while tumor necrosis factor-alpha levels were undetectable both before and after propionyl-L-carnitine administration.

CONCLUSIONS

The topical treatment with a new formulation containing propionyl-L-carnitine seems to be safe and effective in improving the histologic features in patients with inactive or mild ulcerative colitis, as an alternative to conventional therapy.

Chronic taurine supplementation ameliorates oxidative stress and Na+ K+ ATPase impairment in the retina of diabetic rats

This study evaluates the effect of 4 months supplementation with 2% and 5% taurine (w/w) on the retina of diabetic rats. In non-diabetic rats, taurine does not modify glycemia, body weight, retinal conjugated dienes (CD), lipid hydroperoxide (LP), and Na(+)K(+)ATPase activity. In diabetic rat, at 2, 4, 8, 16 weeks following the onset of diabetes, retinal CD and LP are significantly and progressively increased, while pump activity is gradually and significantly reduced. In taurine supplemented diabetic rats, glycemia is not affected but lipid peroxidation is significantly decreased. Finally, taurine preserves ATPase activity being 5% more effective than 2% taurine. We conclude that taurine supplementation ameliorates biochemical retinal abnormalities caused by diabetes, thereby suggesting that taurine may have a role in the prevention of retinal changes in diabetes.

Mechanisms of hyperinsulinaemia in Child's disease grade B liver cirrhosis investigated in free living conditions

AIMS

Human liver cirrhosis is commonly associated with increased fasting and glucose induced insulin concentrations. However, whether the hyperinsulinaemia is a consequence of increased pancreatic insulin secretion, decreased hepatic insulin removal, or impaired feedback regulation of insulin secretion is still doubtful. To investigate these issues, insulin secretion-during 24 hours of standardised living conditions-insulin sensitivity, and hepatic insulin extraction were assessed in cirrhotic patients compared with matched healthy subjects.

PATIENTS

Nine Child's disease grade B cirrhotic patients and seven healthy volunteers, participated in the study. The subjects were studied on two separate days, one for the assessment of insulin secretion during a standardised 24 hour life period (calorimetric chamber), and one for the determination of insulin sensitivity.

METHODS

Insulin secretion rates were reconstructed from plasma C peptide concentrations by deconvolution, and indices of beta cell function were derived using a mathematical model describing the functional dependence of insulin secretion on plasma glucose concentrations. Insulin sensitivity was determined using the euglycaemic hyperinsulinaemic clamp technique.

RESULTS

Cirrhotic patients showed a marked hypersecretory response, both in absolute terms (mean (SEM) 295 (53) versus 138 (11) nmol/m(2), p<0.02), and in relation to glucose (175 (26) versus 57 (5) pmol/min/m(2), p<0.02). In particular, the beta cell dose-response function was shifted upward compared with controls. The sensitivity of insulin secretion to the rate of glucose change was also increased. Insulin sensitivity, markedly reduced in cirrhosis (157 (10) versus 296 (30) ml/min/m(2), p<0.002), was strongly inversely correlated (r=0.89, p<0.002) in these patients with insulin secretion at 5 mM glucose. Insulin clearance and hepatic insulin extraction were not reduced. A frank hypermetabolism with increased lipid oxidation was found in this series.

CONCLUSIONS

This study suggests that hyperinsulinaemia, at least in Child's disease grade B cirrhotic patients, is the consequence of increased beta cell sensitivity to glucose, while hepatic insulin extraction does not seem to play a significant part.

Skeletal muscle triglycerides lowering is associated with net improvement of insulin sensitivity, TNF-alpha reduction and GLUT4 expression enhancement

AIMS/HYPOTHESIS

The aim of the present study was to investigate the relationship between intramyocytic triglycerides levels, muscle TNF-alpha and GLUT4 expression and insulin resistance.

METHODS

Insulin sensitivity was studied in 14 severely obese women (BMI>40 kg/m(2)), before and 6 months after low-dietary intake or bariatric malabsorptive surgery (bilio-pancreatic diversion, BPD), by the euglycaemic hyperinsulinaemic clamp technique, while the amount of intramyocytic triglycerides was chemically measured in needle muscle biopsies. Using reverse transcriptase-polymerase chain reaction analysis, the muscle mRNA expression of TNF-alpha and GLUT4 was also investigated.

RESULTS

The weight loss after surgery was 25.98+/-5.81 kg (P<0.001), while that obtained with the diet was 5.07+/-5.99 kg (P=NS). Marked decrease in TNF-alpha mRNA levels (76.67+/-12.59 to 14.01+/-5.21 AU, P<0.001) were observed in comparison with pre-treatment, whereas GLUT4 was significantly increased (62.25+/-11.77-124.25+/-21.01 AU, P<0.001) only in BPD patients. Increased glucose uptake (M) was accompanied by a significant decrease of TNF-alpha mRNA (76.67+/-12.59-14.01+/-5.21 AU, P<0.01) and an increase of GLUT4. The amounts of TNF-alpha mRNAs in skeletal muscle correlated inversely with GLUT4 mRNAs and directly with intramyocytic triglycerides levels. In a step-down regression analysis (r(2)=0.95) TNFalpha mRNA (P=0.0014), muscular TG levels (P=0.018), and GLUT4 mRNA (P=0.028) resulted to be the most powerful independent variables for predicting M values.

CONCLUSION/INTERPRETATION

These findings suggest that insulin resistance in morbidly obese patients is positively associated to the intramyocytic triglycerides content and to TNF-alpha gene expression and inversely correlated to GLUT4 expression.

Pharmacological approaches to the management of alcohol addiction

Alcohol abuse and alcoholism represent a world-wide problem, both from a medical and a social point of view. In the past the therapy for patients affected by alcoholism was based mainly on the psychological approach. In recent years the use of pharmacotherapy together with psychosocial interventions have enhanced the percentage of success in maintaining alcoholic patients in remission. The present review discusses the main drugs experimented both in preclinical and clinical studies. Pharmacotherapy of alcohol dependence seems to be effective in both alcohol-related emergencies and prevention relapse. However, pharmacotherapy should not be considered as the only form of treatment but as an integrated part of a multimodal approach including psychological and social support.

Computing DIT from energy expenditure measures in a respiratory chamber: a direct modeling method

The possibility of computing Diet Induced Thermogenesis (DIT) is an important feature of metabolic investigations. However, methodological problems have affected the determination of DIT in the indirect calorimetric chamber. DIT has been commonly estimated by regressing energy expenditure on a measure of physical activity. Although used for many years as the only feasible approach to calculate DIT in a respiratory chamber, this traditional method has been criticized because of an apparent underestimation of the DIT, but no alternative method has been suggested so far. The present work proposes to estimate DIT directly by means of a mathematical model. This approach also allows to simultaneously estimate other parameters, namely resting energy expenditure (REE), physical activity (PA) and physical exercise (PE).

Main physiopathologic mechanisms involved in hepatic drug reactions

The liver has a pivotal role in drug metabolism and hepatic drug reactions are frequent events, accounting for 5% of cases of jaundice or acute hepatitis in the community. The importance of hepatic drug reactions lies not only in their frequency, but also in the great number of molecules that can cause this type of lesions and in their variable gravity. This review will show the main factors implicated in drug metabolism which can explain the different susceptibility in developing hepatic drug reaction, the possibility that it may manifest as a wide spectrum of clinical syndromes or that a single agent may cause more than one lesion (a relevant problem not only for the clinician, but also for the pathologist).

Sex hormone-binding globulin levels and cardiovascular risk factors in morbidly obese subjects before and after weight reduction induced by diet or malabsorptive surgery

One of the main goals of weight reduction in morbidly obese subjects is its benefit on coronary heart disease (CHD) risk. A cross-sectional study was designed to randomly assign 79 morbidly obese subjects (27 men and 52 women; age: 30-45 years) either to a diet protocol (20 kcal per kg fat-free mass (FFM); 55% carbohydrates, 30% fat, and 15% proteins) or to malabsorptive surgery (biliopancreatic diversion). Fatness parameters, measured by dual-energy X-ray absorptiometry, lipid profile, insulin, leptin, sex steroid hormones and sex hormone-binding globulin (SHBG) levels were compared at baseline and 1 year after the beginning of the study. The data showed that plasma SHBG levels, but not testosterone levels, correlated negatively to fasting insulin levels and positively to HDL-cholesterol in both men and women. Total leptin levels were significantly lower (P<0.0001) in post-BPD subjects of both sexes compared to dietary treated obese subjects. The logarithm of plasma leptin correlated significantly and positively with insulin but negatively with SHBG.A step-down regression analysis showed that FFM and SHBG, but not insulin levels, were the most powerful independent variables for predicting HDL-cholesterol levels in morbidly obese patients. The negative relationship between SHBG levels and CHD risk appears to be mediated by a concomitant variation in body fatness. Finally, in obese patients, SHBG levels seem to be an indicator of total adiposity rather than an index of an altered insulin/glucose homeostasis.

New bioimpedance model accurately predicts lower limb muscle volume: validation by magnetic resonance imaging

Conventional bioimpedance analysis (BIA) methods now simplify the representation of lower limb geometry and electrical properties for body composition estimation. In the present study, a three-dimensional model of the lower limb was assembled by segmentation of magnetic resonance cross-sectional images (MRI) for adipose tissue, skeletal muscle, and bone. An electrical network was then associated with this model. BIA and MRI measurements were made in six lean subjects (3 men and 3 women, age 32.2 +/- 6.9 yr). Assuming 0.85 S/m for the longitudinal conductivity of the muscle, the model predicted in the examined subjects an impedance profile that conformed well to the BIA impedance profile; predicted and measured resistances were similar (261.3 +/- 7.7 vs. 249 +/- 9 Omega; P = not significant). The resistance profile provided, through a simpler model, muscle area estimates along the lower limb and total leg muscle volume (mean 4,534 cm(3) for men and 4,071 cm(3) for women) with a mean of the absolute value of relative error with respect to MRI of 6.2 +/- 3.9. The new approach suggests that BIA can reasonably estimate the distribution and volume of muscles in the lower extremities of lean subjects.

Enteral diet in Crohn's disease. Nutritional and therapeutic implications in patient's management

Inflammatory bowel diseases (IBD) are often characterized by impairment of nutritional status. Crohn's disease (CD) patients, especially in the active phase of disease, show a reduced body weight, due to the reduction of lipid stores, in spite of lean mass depletion. Fat mass reduction has been correlated to an increased utilization of lipids as fuel substrate. The alterations of nutritional status are able, in turn, to influence, as independent factors, the disease course and patient prognosis. A disease's treatment based only on pharmacologic therapy, especially on corticosteroid use in the active phases, often does not take into account the relevant need for preserving a normal nutritional status. In this connection, enteral nutrition has been shown to be able to improve nutritional status and induce and maintain remission. We present some of the possible mechanisms of efficacy of enteral feeding and some rules to attempt to treat patients with IBD, especially those with Crohn's disease.

Glucose disposal in morbidly obese patients in the early post-operative period

BACKGROUND

In surgical patients, operative stress causes protein catabolism, muscle mass loss, and impaired glucose tolerance. We investigated fuel metabolism and glucose and protein turnover in 15 obese subjects who underwent biliopancreatic diversion (BPD) by using stable labelled isotopes.

METHODS

6 males and 9 females (age 45.11 +/- 8.9 years, BMI of 48.85 +/- 4.43 kg/m2) who underwent BPD were studied, and the APACHE II score was calculated. Patients were studied 3 times (before BPD, 1st and 3rd postoperative day). Glycemia was stable--maintained by continuously infusing Rapid insulin. Each day of the study, the patients received a primed, constant infusion of [15N2] urea, and, 180 min after, a [6.6-2H] glucose infusion started and continued for 3 hours. Indirect calorimetry was performed during the study, under TPN (30 kcal/kg).

RESULTS

The APACHE score was lower on the 3rd postoperative day than on the 1st postoperative day (7.4 +/- 2.7 vs 6.3 +/- 2.6, p < 0.05). The npRQ was different throughout the post-operative period (0.82 +/- 0.03 vs 0.9 +/- 0.06, p < 0.05), while urinary nitrogen excretion, energy expenditure and glycemia did not change. The insulin amount infused was lower during the 3rd post-operative day (44.25 +/- 12.3 vs 64.12 +/- 11 UI on the 1st one, p < 0.05). Insulinemia was lower during the 3rd than during the 1st postoperative day (66.4 +/- 9.49 vs 117.44 +/- 8.49 microU/ml, p < 0.05). Non-essential fatty acid levels were higher on the 3rd post-operative day than on the 1st one (0.98 +/- 0.6 vs 0.45 +/- 0.34 mmol/L, p < 0.01). No differences were observed in glucose and urea turn-over.

CONCLUSION

The metabolic pattern of morbidly obese patients operated by BPD was similar to that of other critically ill patients previously studied in the literature. Furthermore, the increased glucose oxidation rate observed on the 3rd post-operative day was coupled with an improved clinical condition.

Different limit to the body's ability of increasing fat-free mass

It is a common understanding that fat-free mass (FFM) increases with body weight. However, limited information is available as to the relationship between weight increase and changes in body composition. We performed the present study to determine quantitatively the relationship between body composition, total body weight, age, and sex. Body composition data were obtained by isotopic dilution on 273 subjects ranging in body mass index (BMI) from about 13 to 70 kg/m(2). Adipose free tissue (AFT) was modeled as a nonlinear, increase-limited function of body weight. Model parameters were evaluated as functions of sex, age, and height. The relationship between AFT and body weight was very well approximated by means of the nonlinear model (R(2) =.95), with maximal AFT being determined by both sex and height and with AFT growth rate determined only by sex. AFT clearly shows a nonlinear behavior, tending to increase less and less with progressively increasing body weight. With the proposed model, an asymptotic maximal AFT may be postulated. The organism seems to have an intrinsic limitation to how much skeletal muscle development may take place to accommodate the necessities of an ever-increasing load. These limits are different between the sexes, with women tending to approach more rapidly than men a lower maximal AFT for the same height.

Blunted glucose metabolism in anorexia nervosa

Only few studies have specifically investigated diet-induced thermogenesis in anorexia nervosa. Twenty women, 10 anorectics (body mass index [BMI] = 14.98 +/- 1.02 kg/m(2)) and 10 controls (BMI = 22.53 +/- 0.75 kg/m(2)) were studied. Body composition was evaluated by isotopic dilution. Respiratory gas exchange was measured by indirect calorimetry. An oral glucose load (75 g) was administered to the anorectics (A) and the controls (CA). The controls underwent a second load (CB) with a higher glucose amount (1.85 +/- 0.11 g/kg body weight [BW]) to compare with the load taken by anorectics. Glucose-induced thermogenesis (GIT) was computed for 300 minutes following the load as the percent increase of energy expenditure (EE) above resting-EE (REE). Serum glucose levels were lower in anorectic patients both in fasting (3.46 +/- 0.66 v 5.23 +/- 0.23 in CA, P <.01 v 5.32 +/- 0.34 mmol in CB, P <.01) and in the postprandial state (glucose area under the curve [AUC] 175.51 +/- 6.40 v 289.80 +/- 7.30 in CA, P <.01 v 324.65 mmol in CB, P <.001); insulin AUC was lower, 1,926 +/- 452 versus 41,148 +/- 2,071 in CA, P <.0001 versus 60,765.5 pmol in CB, P <.0001. REE, normalized by fat-free mass (FFM), was similar between groups. GIT was lower in anorectics (3.58 +/- 1.20 v 5.45 +/- 1.83 in CA, P <.05 v 9.09% +/- 1.05% in CB, P <.01). Glucose oxidation was higher in anorectics than in CA (689.44 +/- 72.22 v 333.32 +/- 32.98 micromol/L/min, P <.001), but similar to CB. Lipid oxidation become negative after 30 minutes in anorectics (postprandial lipid oxidation = -93.58 +/- 39.86 v 370.61 +/- 21.73 in CA, P <.0001 v 119.01 +/- 12.32 micromol/L/300 min in CB, P <.0001). Anorectic patients displayed a low REE and GIT. Carbohydrate oxidation was similar between groups; lipid oxidation was extremely reduced. An increased protein catabolism was observed.

Oxidation of D-[U-(14)C] glucose and [1,12-(14)C] dodecanedioic acid by pancreatic islets from Goto-Kakizaki rats

In pancreatic islets from hereditarily diabetic GK rats, [1,12 -(14)C] dodecanedioic acid (5.0 mM) was oxidized at a rate representing about 5 % of that of D-[U - (14)C] glucose (8.3 mM). Dioic acid and hexose failed to exert any significant reciprocal effects on their respective oxidation. The production of (14)CO(2) from [1,12 -(14)C] dodecanedioic acid was proportional to its concentration in the 0.2 - 5.0 mM range. These results were essentially comparable to those obtained in islets from control rats. They extend, therefore, to GK rats the knowledge that dodecanedioic acid acts as a nutrient in pancreatic islet cells.

Unreliable use of standard muscle hydration value in obesity

Intramuscular water content is assumed to be constant in humans independent of their anthropometric characteristics. To verify whether this assumption is correct, intramuscular water, proteins, glycogen, and both total and intramyocytic triglycerides were measured in 51 samples of rectus abdominis muscle obtained from 16 lean and 35 overweight and obese subjects (body mass index cutoff 24.9 kg/m2). Data (referred to as wet tissue) were analyzed by means of a composition model at the cellular level of the skeletal muscle (SM). The average SM water content was 76.3 +/- 3.3% in normal-weight individuals and 65.7 +/- 5.8% in obese subjects (P < 0.0001). Total triglycerides were 5.5 +/- 2.3% in controls and 19.0 +/- 7.0% in obese subjects (P < 0.0001). The intramyocytic triglyceride fraction was also increased in obese subjects. The composition model provides an explanation for the negative correlation between total triglycerides and intramuscular water, and some of the model parameters were determined from the experimental data. In conclusion, although the hydration of fat-free SM mass may be unchanged in obese subjects, the hydration of in toto muscle mass decreases as its lipid content increases.

Effects of aliphatic dioic acids and glycerol-1,2,3-tris(dodecanedioate) on D-glucose-stimulated insulin release in rat pancreatic islets

Aliphatic dioic acids have been proposed as alternative nutrients in selected clinical situations. In this study, their possible insulinotropic action was investigated in isolated rat pancreatic islets prepared from fed rats. Azelaic acid, sebacic acid and tridecanedioic acids, when tested at a 10.0 mm concentration, were found to augment insulin release evoked by D-glucose (7.0 mm) in the pancreatic islets. Likewise, glycerol-1,2,3-tris(dodecanoedioate), when used at concentrations close to 1.0 mm, increased the secretory response to the hexose. It is speculated that these findings may extend to insulin-producing cells, the knowledge that aliphatic dioic acids or their esters may act as energy substrates, e.g. in parenteral nutrition.

Oxidation of [1,12-14C]dodecanedioic acid by rat pancreatic islets

Several aliphatic dioic acids were recently reported to stimulate insulin release in isolated rat pancreatic islets incubated at close-to-physiological D-glucose concentrations. In order to gain insight into the mode of action of these acids in pancreatic islet B-cells, the oxidation of [1,12-14C]dodecanedioic acid (5.0 mM) was now measured in rat islets. Expressed as pmol of [1, 12-14C]dodecanedioic acid equivalent, the production of 14CO2 was close to 1.0 pmol/islet per 120 min, representing about 8% of that attributable to the oxidation of D-[U-14C]-glucose (8.3 mM). The dioic acid and the hexose failed to exert any significant reciprocal effect upon their respective oxidation rate. These findings support the view that the insulinotropic action of dodecanedioic acid, and presumably other aliphatic dioic acids, is causally linked to their capacity to act as nutrients in pancreatic islet cells.

Subclinical hepatic encephalopathy: role of tryptophan binding to albumin and the competition with indole-3-acetic acid

BACKGROUND

The role of tryptophan (TRY) and its metabolites in the pathogenesis of hepatic encephalopathy is conflicting. The aim of the present study is to investigate in posthepatitis cirrhotic patients with encephalopathy the serum levels of TRY and those of its metabolite indole-3-acetic acid, as well as TRY binding curve to serum albumin and the competition with indole-3-acetic acid. The presence of a relationship between encephalopathy severity and circulating free TRY was also investigated.

METHODS

Serum TRY and indole-3-acetic acid were analyzed by HPLC; binding of TRY to serum albumin and the competition with indole-3-acetic acid was studied by equilibrium dialysis.

RESULTS

Serum-free TRY was significantly higher in cirrhotic patients (43.33 +/- 14.70 vs 28.87 +/- 8.77 mumol/L, P = 0.02). The binding capacity of albumin was reduced in cirrhotics and further decreased by the addition of indole-3-acetic (K = 6.63 +/- 0.97 x 10(3) mol/L-1, gamma = 1.16 +/- 0.45 x 10(2) mol/L-1 in normal sera vs K = 1.04 +/- 0.20 x 10(3) mol/L-1, gamma = 1.91 +/- 0.92 10(2) mol/L-1 in cirrhotic sera). A multivariate analysis showed that among the psychometric tests the only independent predictor of serum levels of free TRY was the Block Design (R2 = 0.94, B = 0.16 +/- 0.01, beta = 0.97; P < 0.0001).

CONCLUSIONS

A high percent ratio of free/total TRY and indoleacetic acid (IAA) was found in cirrhotic patients with hepatic encephalopathy. The concentrations of serum-free IAA and TRY correlated with the degree of subclinical encephalopathy, suggesting a role of these compounds in the development of mental derangement in liver cirrhosis.

Changes in body composition, substrate oxidation, and resting metabolic rate in adult celiac disease patients after a 1-y gluten-free diet treatment

BACKGROUND

The incidence of celiac disease has been on the rise in both Europe and the United States. Celiac disease patients are at high risk of undernutrition because of nutrient malabsorption.

OBJECTIVE

The aim of the present study was to evaluate changes in body composition and energy metabolism in a group of patients with celiac disease before and after consumption of a gluten-free diet (GFD).

DESIGN

Body composition (by anthropometry and isotopic dilution), resting metabolic rate (RMR), and substrate oxidation rates (by indirect calorimetry) were assessed in 39 adult celiac disease patients (16 men and 23 women) with a mean (+/-SD) age of 29. 9 +/- 7.6 y, weight of 58.3 +/- 6.6 kg, and percentage body fat of 20.1 +/- 6.7%, and in 63 (29 men and 34 women) age- and height-matched control subjects (age: 33.2 +/- 8.1 y; weight: 66.8 +/- 6.6 kg; and percentage body fat: 25.4 +/- 3.7%). Celiac disease patients were studied twice, at diagnosis and 1 y after treatment with a GFD.

RESULTS

Before treatment, celiac disease patients had a lower body weight (P < 0.05) and a higher carbohydrate oxidation rate (P < 0.01) than did control subjects. Carbohydrate oxidation rates correlated positively with fecal lipid loss in untreated celiac disease patients (r = 0.80, P < 0.0001). After the GFD, percentage body fat was higher in celiac disease patients than in control subjects (P < 0.01), and lipid intakes tended to be higher than before treatment.

CONCLUSIONS

This longitudinal study showed that the GFD treatment significantly increased body fat stores. Untreated patients preferentially utilized carbohydrates as a fuel substrate, probably as a consequence of both lipid malabsorption and a high carbohydrate intake, and lipid utilization increased with the restoration of the intestinal mucosa.

Serum leptin levels in post-hepatitis liver cirrhosis

BACKGROUND/AIMS

Little information is available on the involvement of leptin in clinical conditions associated with malnutrition, such as liver cirrhosis. The behaviour of serum leptin in patients with different Child-Pugh score, post-hepatitis liver cirrhosis and insulin sensitivity has therefore been investigated and compared with that in alcoholic Child C patients.

METHODS

Sixty-four patients, aged 51 to 62 years, with different degrees of post-hepatitis cirrhosis or Child C alcoholic cirrhosis were compared with 15 age-matched control subjects. Body composition was estimated by skinfold thickness. Serum leptin, glucose and insulin were assayed.

RESULTS

In post-hepatitis patients a significant reduction in leptin levels was observed as the Child-Pugh score worsened (men: 2.94+/-1.61 in Child C vs 6.78+/-2.49 ng/ml in controls, p<0.001; women: 4.14+/-0.66 in Child C vs 16.16+/-3.90 ng/ml in controls, p<0.02). Conversely, only the men with alcoholic liver cirrhosis showed a significant difference in leptin concentration compared to controls (8.5+/-2.1 vs 16.4+/-7.9 kg, p<0.05). In particular, Child C, alcoholic cirrhotic women had a significantly (p=0.03) higher level of leptin than post-hepatitis matched women. A positive correlation was observed between leptin and fat mass (men R2=0.59, p<0.0001 and women R2=0.65, p<0.0001). While fasting levels of serum leptin correlated significantly with insulin concentrations in controls, a similar relationship was not observed in the cirrhotic population, which displayed higher insulin concentrations than controls.

CONCLUSIONS

In contrast to findings in alcoholic cirrhotic women, low leptin values in post-hepatitis cirrhotic patients mainly represent the expression of a reduced fat mass.

Acetyl-L-carnitine infusion increases glucose disposal in type 2 diabetic patients

Little information is available in the literature on the effect of L-carnitine to improve glucose disposal in healthy control subjects and type 2 diabetic patients. No data are reported on the pharmacological properties of acetyl-L-carnitine (ALC) in type 2 diabetes mellitus. The present study evaluates glucose uptake and oxidation rates with either ALC or placebo administration in 18 type 2 diabetic patients. On different days, each patient received both a primed-constant infusion of ALC (5 mg/kg body weight [BW] priming bolus and either 0.025, 0.1, or 1.0 mg/kg BW/min constant infusion) and a comparable placebo formulation. During the infusion period, continuous indirect calorimetric monitoring and a euglycemic-hyperinsulinemic clamp (EHC) study were performed. The total end-clamp glucose tissue uptake (M value) was significantly increased by the administration of ALC (from 3.8 to 5.2 mg/kg/min, P = .006), and the dose dependence of this effect reached borderline statistical significance (P = .037). The increase in the M/I ratio was also highly significant after ALC administration (from 3.9 to 5.8 x 10(-2) mg/kg/min/(microUI/mL, P < .001), while no statistically significant effect was attributable to the different dosages. The increase in the M value was related to increased glucose storage (highly significant effect of ALC) rather than increased glucose oxidation (no statistical significance). In conclusion, the effect of ALC on glucose disposal has no relationship to the amount administered. This could be due to an effect of ALC on the enzymes involved in both the glycolytic and gluconeogenetic pathways, and a possible reversibility of glycogen synthase inhibition in diabetic subjects.

Body composition and energy expenditure after weight loss following bariatric surgery

OBJECTIVES

To assess the effectiveness of biliopancreatic diversion (BPD) in the treatment of morbid obesity and to evaluate how the procedure affects body weight.

SUBJECTS

Fourteen morbidly obese subjects studied before and 30 months after BPD and fifteen healthy volunteers matched for age, sex and height (controls).

METHODS

Comparison of the following parameters were made in the study groups before surgery and 30 months after BPD and with those of the controls group: fat mass, fat-free mass, non-protein substrate oxidation, basal metabolic rate, plasma glucose, insulin and free fatty acid concentrations.

RESULTS

Obese subjects lost 60.38+/-10.71 kg of weight during 18 months following surgery and then remained stable for another 12 months, when this study was performed. Weight loss was substantially due to a loss of fat mass (FM: 60.13+/-13.01 kg before and 19.02+/-8.61 kg after BPD; p<0.001). FM were not statistically different between post-obese subjects and controls; however, post-obese patients retained significantly more fat free mass (FFM) than controls. Subsequently, basal metabolic rates of post-obese subjects were higher than those of the control group (p<0.05). Fasting non-protein respiratory quotient (npRQ) was significantly lower before BPD than 30 months after the surgery (0.798+/-0.04 vs. 0.90+/-0.048, p<0.001), suggesting that, while obese, patients oxidized more lipids than carbohydrates. Moreover, fasting and two-hour plasma glucose and insulin concentrations decreased significantly after BPD to values comparable to those of the control group.

CONCLUSION

Weight loss in obese patients after BPD is mainly due to lipid malabsorption, but increased energy expenditure associated with retaining a high FFM in physically active post-obese subjects may also play a role, enabling them to maintain long-term reduced body weights.

Disposition of dodecanedioic acid in humans

The disposition of dodecanedioic acid (C12) was investigated in six overnight-fasting healthy male volunteers, who received a 165-min i. v. infusion of 42.45 mmol of C12 added to 150 microCi of [1-12-(14)C]C12. Blood samples were collected up to 360 min after the start of infusion, and concentration of serum labeled C12 was determined. Expired radioactivity (microCi/min) was measured up to 600 min and at 24 h. The 24-h C12 urinary excretion was around 5% of the administered amount. The percentage of C12 oxidized was 81.7 +/- 9.5% (mean +/- S.D.) of administered amount as estimated from the area under the curve of measured (14)CO(2) expiration rate. C12 kinetics was described by assuming a single compartment. A saturable rate of C12 tissue uptake (model A) and a linear rate of tissue uptake (model B) were considered. The kinetics of CO(2) produced by C12 oxidation was described by a fast pathway acting in parallel to a slow pathway modeled by first order kinetics. Parameters of model B were estimated for each subject, whereas model A was identified by fitting the pooled data of all subjects. On the basis of estimates obtained from model B, an average calorie delivery of 500 kcal/day was predicted in the plateau phase for the infusion rate of our experiments. When estimated from model A, the maximal rate of tissue uptake was 0.38 +/- 0.08 mmol/min, with a maximal calorie delivery of 750 kcal/day. These results appear promising for C12 utilization in parenteral nutrition, because C12 elimination with urine is low, whereas tissue uptake and oxidation are rather efficient.

Insulin resistance directly correlates with increased saturated fatty acids in skeletal muscle triglycerides

A close relationship between elevated plasma free fatty acid (FFA) levels and insulin resistance is commonly reported in obese subjects. The aim of the present study was to evaluate the role of intramuscular triglyceride (mTG) and FFA levels in insulin sensitivity in 30 nondiabetic normal-weight or obese subjects (18 with body mass index [BMI] = 21.8 +/- 3.3 kg/m2 and 12 with BMI = 34.6 +/- 2.7 kg/m2) who underwent minor abdominal surgery. Body composition was estimated by isotopic dilution, substrate oxidation by indirect calorimetry, and whole-body glucose uptake by euglycemic-hyperinsulinemic clamp (EHC). Glucose uptake (M) value negatively correlated with the MTG level (R2 = -.56, P < .0001), which was increased in obese patients (11.6 +/- 2.2 v 6.2 +/- 1.4 micromol/g wet weight muscle tissue, P < .0001). The TG fatty acid profile was significantly different in the 2 groups: an increased concentration of saturated fat was present in obese patients (unsaturated to saturated ratio, 1.89 +/- 0.40 v2.19 +/- 0.07, P < .0001). Stepwise linear regression analysis of total mTGs and palmitic and oleic fractions on the M value showed that only TGs and palmitic acid were significantly related to glucose uptake (R2 = .66, P < .0001). Furthermore, among the other anthropometric variables, only the BMI was significantly correlated with MTGs (R2 = .71, P < .0001). In conclusion, not only the MTG concentration but also the FFA pattern seems to affect insulin-mediated glucose uptake. A pivotal role might be played by a high saturated fatty acid content in the TGs.

Effect of a vegetable-protein-rich polymeric diet treatment on body composition and energy metabolism in inactive Crohn's disease

OBJECTIVE

Since malnutrition and lactose intolerance are frequently reported in Crohn's disease (CD), we evaluated the differences in terms of compliance-to-treatment and nutritional status in inactive CD patients after two different treatments using either a standard polymeric diet or a vegetable-protein-rich and lactose-free diet.

STUDY DESIGN

A case-control study.

SUBJECTS

Forty CD patients with inactive disease were randomly divided into two groups. Group A (10 men; aged 33.9+/-7.2 years; BMI, 21.8+/-1.7 kg/m2) received a conventional polymeric enteral diet, while group B (10 men; aged 35.6+/-6.8 years; BMI, 21.4+/-1.8 kg/m2) was administered a soy-rich and lactose-free polymeric diet, over a 4-week period.

METHODS

All the patients had a clinical and laboratory examination. Body composition was assessed by isotopic dilution and resting metabolic rate (RMR), and substrate oxidation rates were measured by indirect calorimetry.

RESULTS

Body weight significantly increased after treatment in both groups (A, P<0.05; and B, P<0.01), as well as fat-free mass (A, P<0.05; and B, P<0.05) and fat mass (A, P<0.05; and B, P<0.01). RMR slightly increased, although it did not reach statistical significance. Treatment did not influence substrate oxidation rates. Group B lactose-intolerant patients reported a greater compliance-to-treatment than those in group A.

CONCLUSIONS

This study showed that a polymeric enteral diet rich in vegetable protein and not containing milk protein, eaten at home, with no need for positioning a nasogastric tube, significantly improved body composition in inactive and lactose-intolerant CD patients, with no effect on energy metabolism, suggesting that it could be useful in improving nutritional status in these patients.

Wasting in gastrointestinal tract cancers: clinical and etiologic aspects

One of the major complications found in patients affected by malignancy of the gastrointestinal tract is represented by an alteration of nutritional status, up to real cachexia. The factors responsible for the severe nutritional deficiencies are: metabolic alterations, which involve carbohydrate, lipid and protein metabolism; the reduced availability of nutritional substrates, due to neoplastic growth that, by expanding locally or destroying the affected organ, determines alterations of deglutition, digestion and food absorption; the effects of surgical therapy, radiotherapy and chemotherapy, which are able to cause temporary or permanent nutritional deficiencies; the effects of immunological mediators, and above all of tumor necrosis factor-alpha (TNF-alpha). In fact, TNF-alpha is considered the main mediator of cancer cachexia as it is responsible for different metabolic alterations, both directly and by the activation of other mediators, such as lipid mobilizing factor (LMF) and protein mobilizing factor (PMF). In addition, a negative energy balance in cancer patients could occur as a consequence of increased energy requirements. In this connection, patients with different neoplasia localisation, show high or within the normal range energy expenditure values. These data indicate that the increase in energy metabolism is not likely to represent the main determining factor in neoplastic cachexia. In conclusion, since patients affected by malignancy of the gastrointestinal tract showed a reduction in body weight, fat and fat-free mass, accurate evaluation of nutritional status should be useful in the management and follow-up of these patients.

A new HPLC method for the direct analysis of triglycerides of dicarboxylic acids in biological samples

Dicarboxylic acids (DA) are alternate lipid substrates recently proposed in parenteral nutrition. Two new derivatives of DA, a triglyceride of sebacic (TGC10) and one of dodecanedioic (TGC12) acid have been synthesised in order to reduce the amount of sodium given with the unesterified forms. The present paper describes a rapid and direct high-performance liquid chromatographic method (HPLC) for the analysis of these substances in both plasma and urine. Thirty-six male Wistar rats were rapidly injected with 64 mg of TGC10 or 53 mg of TGC12. The triglycerides and their products of hydrolysis were measured in plasma samples taken at different times. For the dose of 500 ng the intra-assay variations ranged from 6. 80+/-0.35% for TGC10 to 18.6+/-3.20% for TGC12 and the inter-assay variations were from 4.44+/-2.21% for TGC10 to 15.0+/-6.72% for TGC12. The detection limit for both triglycerides was 5 ng. This rapid and direct HPLC method could have practical implications in monitoring the concentration of both triglycerides and free forms of DA in biological samples of patients who might benefit from the administration of these substances during parenteral nutrition regimens.

Comparison of insulin response to intravenous glucose in healed myocardial infarction, in "cooled-off" unstable and stable angina pectoris, and in healthy subjects

Fasting and postglucose hyperinsulinemia are recognized risk factors for acute coronary events. The insulin reactivity of patients with acute coronary syndromes, however, has not been carefully compared with that of patients with chronic stable angina. We used Bergman's minimal model to analyze the insulin response to intravenous glucose in 21 subjects: 8 patients with previous (>3 months) acute coronary syndrome but no effort-related angina; 6 patients with stable effort angina but no prior acute event; and 7 healthy controls. Diabetes mellitus, systemic hypertension, dyslipidemias, and obesity were excluded. All patients underwent coronary angiography. Insulin sensitivity, glucose effectiveness, and glucose tolerance were determined from insulin and glucose concentrations measured frequently up to 3 hours after a 0.33 g/kg intravenous glucose bolus. Patients with previous unstable angina or acute myocardial infarction had less extensive disease at angiography than patients with stable angina (p = 0.007). Both patient groups had higher basal and 180-minute insulinemia than controls (p <0.0007). However, patients with stable angina did not differ significantly from controls with regard to early and late insulinemic response to glucose. In contrast, patients with previous acute onset of ischemia had significantly greater 180-minute integrated insulinemia (p = 0.04) and reduced insulin sensitivity (p = 0.05) after the glucose challenge than did the stable angina group. These data suggest that patients with acute presentation of coronary artery disease, compared with patients with uncomplicated chronic stable angina, have an impaired insulin response to glucose despite less extensive coronary disease at angiography.

Multivariate identification of metabolic features in inflammatory bowel disease

Weight loss and malnutrition are commonly reported in inflammatory bowel disease (IBD), but differences between Crohn's disease (CD) and ulcerative colitis (UC) patients have rarely been pointed out. In this regard, a sample of 102 consecutive patients with a diagnosis of either CD (n = 63, 33 males) or UC (n = 39, 25 males) based on previously reported clinical, morphologic, and histopathologic criteria were studied. Twenty-six anthropometric and metabolic variables were measured upon admission. Body composition was assessed by both anthropometry and bioimpedance measurements, and energy expenditure and substrate oxidation were assessed by indirect calorimetry. The data were subjected to principal-component analysis and to factor rotation to derive a set of a few basic independent descriptors of the metabolic features of each subject. Six descriptors were found to be responsible for greater than 86% of the total sample variability and to associate very well with mutually disjoint subsets of the original variables. The six summarizing factors are listed in order of decreasing percentage of explained variation (size 41.8%, fatness 17.9%, fuel 12.2%, shape 5.4%, energy 5.2%, and steroid 3.9%). CD and UC patients differed significantly with respect to fatness (CD lower, P = .004) and carbohydrate (CHO) fuel preference (CD lower, P = .030). Hence, CD patients showed a reduced fat mass (FM) compared with UC patients, and from a metabolic point of view, too, CD and UC are not superimposable. In fact, the lower CHO oxidation (CHOox) rate and consequent preferential lipid utilization found in CD patients may be taken into account as a contributing cause of lipid tissue wasting and in planning therapeutic enteral regimens.

Nutritional status and body fluid distribution in chronic alcoholics compared with controls

BACKGROUND

At present few data are available on the total body water (TBW) content and in particular on the distribution of water in the intra- and extracellular compartments (ICW and ECW) of alcoholics. The aim of this study was to evaluate TBW, ICW, and ECW in chronic alcoholic patients.

METHODS

Thirty-six alcoholics meeting DSM-III-R criteria for diagnosis (20 men, 16 women; body mass index [BMI] 22.3+/-2.57 kg/m2) were enrolled. Fifty-four healthy social drinkers (31 men, 23 women; BMI 23.7+/-1.68 kg/m2) matched for age and height were used as controls. Systolic and diastolic blood pressure was measured for all cases. All patients were assessed using specific anthropometric measurements. The waist-to-hip ratio (WHR) was used as an indicator of body fat distribution. TBW was measured by isotopic dilution by giving 100 microCi of tritiated water. ICW and ECW were assessed by multifrequence bioelectric impedance analysis (BIA). Basal metabolic rate (BMR) was measured by indirect calorimetry.

RESULTS

Body weight was lower in the alcoholics than in the controls (61.9+/-5.5 kg vs. 65.8+/-5.2 kg;p < 0.01), essentially due to a reduction in fat mass. Significantly higher WHR values were found in both male (p < 0.001) and female (p < 0.001) alcoholics than in healthy subjects. A higher ECW/TBW ratio was found in the alcoholics compared with the controls, both as a whole (0.53+/-0.04 vs. 0.41+/-0.03; p < 0.0001) and separated by gender (p < 0.001).

CONCLUSIONS

The increased ECW could derive from an increase in cellular permeability related to endothelial damage linked to the vasoconstriction present in the alcoholics and/or to a direct toxic effect of ethanol on cellular membranes. In addition, because the high ECW volumes correlated positively with WHR in the alcoholics, a potential association of these two factors in determining an increased risk of liver disease, hypertension, and cardiovascular disease may exist. Finally, the lower TBW characteristic of women may be one of the reasons for the observed greater rate of toxic effects of ethanol that occur in women.

The steroid resistance of Crohn's disease

BACKGROUND

A partial or complete steroid resistance, whose cause is not yet clarified, has been documented in many patients with long-standing Crohn's disease (CD). The primary aim of this study was to evaluate the number and affinity of serum protein steroid-binding sites in steroid-resistant patients with Crohn's disease. A secondary goal was to measure insulin sensitivity, an indirect index of steroid effectiveness, in these patients.

METHODS

The study included 8 male steroid-resistant patients with active ileal CD and 6 healthy male volunteers. Corticosteroid binding globulin (CBG), binding capacity and affinity for cortisol were measured. The binding of cortisol to normal human serum and to serum of patients with CD was also determined. Whole body glucose uptake and oxidation were assessed by euglycemic hyperinsulinemic clamp and indirect calorimetry.

RESULTS

Crohn's patients showed a significantly greater capacity of serum albumin for cortisol than controls (by about 40%, or about 0.15 moles per mole). Conversely, the binding of cortisol to CBG did not show significant differences between groups. Glucose uptake was higher in Crohn's patients than in normal controls (8.82 +/- 2.50 vs 7.01 +/- 2.24 mg/kgFFM/min; P = 0.036). Basal serum nonesterified fatty acid (NEFA) levels were lower in patients than in controls (459.64 +/- 69.95 vs 1026.48 +/- 112.58 mumol/L; P = 0.002).

CONCLUSIONS

The observed increase in albumin binding might limit the bioactivity of cortisol in patients with Crohn's disease and contribute to the decreased effectiveness and weaker side effects of glucocorticoid therapy in these patients. The increased number of cortisol binding sites on albumin from patients with CD might be correlated with the significant decrease in serum NEFA, which may compete with steroids for the same sites.

Triglyceride-induced diabetes associated with familial lipoprotein lipase deficiency

Raised plasma triglycerides (TGs) and nonesterified fatty acid (NEFA) concentrations are thought to play a role in the pathogenesis of insulin-resistant diabetes. We report on two sisters with extreme hypertriglyceridemia and overt diabetes, in whom surgical normalization of TGs cured the diabetes. In all of the family members (parents, two affected sisters, ages 18 and 15 years, and an 11-year-old unaffected sister), we measured oral glucose tolerance, insulin sensitivity (by the euglycemic-hyperinsulinemic clamp technique), substrate oxidation (indirect calorimetry), endogenous glucose production (by the [6,6-2H2]glucose technique), and postheparin plasma lipoprotein lipase (LPL) activity. In addition, GC-clamped polymerase chain reaction-amplified DNA from the promoter region and the 10 coding LPL gene exons were screened for nucleotide substitution. Two silent mutations were found in the father's exon 4 (Glu118 Glu) and in the mother's exon 8 (Thr361 Thr), while a nonsense mutation (Ser447 Ter) was detected in the mother's exon 9. Mutations in exons 4 and 8 were inherited by the two affected girls. At 1-2 years after the appearance of hyperchylomicronemia, both sisters developed hyperglycemia with severe insulin resistance. Because medical therapy (including high-dose insulin) failed to reduce plasma TGs or control glycemia, lipid malabsorption was surgically induced by a modified biliopancreatic diversion. Within 3 weeks of surgery, plasma TGs and NEFA and cholesterol levels were drastically lowered. Concurrently, fasting plasma glucose levels fell from 17 to 5 mmol/l (with no therapy), while insulin-stimulated glucose uptake, oxidation, and storage were all markedly improved. Throughout the observation period, plasma TG levels were closely correlated with both plasma glucose and insulin concentrations, as measured during the oral glucose tolerance test. These cases provide evidence that insulin-resistant diabetes can be caused by extremely high levels of TGs.

Alterations of nutritional status in the main gastrointestinal pathologies

An impairment of nutritional status up to real malnutrition can frequently be associated to gastrointestinal diseases. The diseases of the gastrointestinal tract can be divided into five groups: those hampering the nutrient physiological transit (especially neoplastic diseases); those affecting the intestinal mucosa (such as chronic inflammatory bowel disease); those determining intraluminal maldigestion; the hepato-biliary diseases and finally, the diseases of the pancreas. In order to correctly evaluate the nutritional status of an individual, besides the determination of the common biochemical parameters, body composition by direct and indirect techniques and energy metabolism by indirect calorimetry should be measured. Patients affected by Crohn's disease showed a lower fat mass content along with higher lipid oxidation compared to patients affected by ulcerative colitis. Patients with coeliac disease at diagnosis had a reduction in both fat and fat-free mass content along with an increased utilisation of carbohydrates as fuel substrate. There are many factors potentially leading to severe malnutrition in pancreatic diseases, especially in the acute form. Due to the primary role played by the liver in the metabolism of energy substrates, an impaired nutritional status might be commonly found in cirrhotic patients. In this connection, our group reported an increased energy expenditure and lipid oxidation, and an insulin-resistant state in compensated liver cirrhotic patients. These alterations seemed to precede and probably to lead to liver-disease-related malnutrition.

Pharmacokinetics of sebacic acid in rats

The pharmacokinetics of disodium sebacate (Sb) was studied in Wistar rats of both sexes. Sebacate was administered either as intra-peritoneal (i.p.) bolus (six doses ranging from 10 mg to 320 mg) or as oral bolus (two doses: 80 and 160 mg). Plasma and urinary concentrations of Sb and urinary concentrations of Sb and its products of beta-oxidation (suberic and adipic acids) were measured by an improved method using gas-liquid chromatography/mass-spectrometry. A single compartment with two linear elimination routes was selected after no increase in significance was shown by an additional compartment and after a saturable mechanism was found to be unsuitable. Both renal and non-renal elimination parameters were obtained by Marquardt non linear fitting of plasma concentrations together with urinary elimination. The data reported are calculated from the analysis on the whole population of rats and referred to an average body weight (bw) of 100 g. The Sb half-time was 31.5 min. The tissue elimination rate was 0.0122 min-1. The overall volume of distribution was found to be 26.817 ml/100 g bw. The renal clearance was 0.291 ml/min/100 g of bw, which is much less than the value of GFR reported in literature (about 1 ml/min/100 g bw), suggesting the presence of Sb reabsorption from the ultrafiltrate. The value of Sb renal clearance was found to be a concentration-independent function, suggesting the presence of a passive back-diffusion. The relative bioavailability of the oral form compared to the i.p. form was 69.09%, showing a good absorption of the drug.

Kinetics of dodecanedioic acid triglyceride in rats

The kinetics of the triglyceride of dodecanedioic acid (TGDA) has been investigated in 30 male Wistar rats after a rapid intravenous bolus injection. TGDA and its product of hydrolysis, nonesterified dodecanedioic acid (NEDA), were measured in plasma samples taken at different times using an improved high-performance liquid chromatographic method. The 24-h urinary excretion of TGDA was 1.54 +/- 0.37 micromol, corresponding to approximately 0.67% of the administered amount. Several kinetics models were considered, including central and peripheral compartments for the triglyceride and the free forms and expressing transports between compartments with combinations of linear, carrier-limited, or time-varying mechanisms. The parameter estimates of the kinetics of TGDA and of NEDA were finally obtained using a three-compartment model in which the transfer of TGDA to NEDA was assumed to be linear, through a peripheral compartment, and the tissue uptake of NEDA was assumed to be carrier limited. TGDA had a large volume of distribution ( approximately 0.5 l/kg body wt) with a fast disappearance rate from plasma (0.42 min-1), whereas NEDA had a very small volume of distribution ( approximately 0.04 l/kg body wt) and a tissue uptake with maximal transport rate of 0.636 mM/min. In conclusion, this first study on the triglyceride form of dodecanedioic acid indicates that it is rapidly hydrolyzed and that both triglyceride and nonesterified forms are excreted in the urine to a very low extent. The tissue uptake rate of NEDA is consistent with the possibility of achieving substantial energy delivery, should it be added to parenteral nutrition formulations. Furthermore, the amount of sodium administered with the triglyceride form is one-half of that necessary with the free diacid.

Comparison between dodecanedioic acid and long-chain triglycerides as an energy source in liquid formula diets

BACKGROUND

Dicarboxylic acids (DA) are water-soluble substances with high-energy density proposed as an alternative lipid substrate for nutrition purposes. The aim of the present study was to investigate the interaction between glucose and DA or long-chain triglyceride (LCT) metabolism after oral administration.

METHODS

Two test meals containing either dodecanedioic acid (C12, the 12-atom DA) or LCT, together with glucose and amino acids, were each administered to five healthy volunteers. Tracer amounts of 14C-dodecanedioic acid were added to the C12 meal to recover expired traced CO2 and estimate the minimum rate of C12 oxidation. Glucose, insulin, and C12 plasma levels were measured for 360 minutes after the test meal. Indirect calorimetry was performed for the duration of the study.

RESULTS

LCTs proved ineffective in promoting their own oxidation after oral administration. On the contrary, C12 was promptly oxidized, a minimum of 21.9%+/-8.3% of the administered amount giving rise to the recovered expired CO2. This difference in metabolic fate was reflected in a sparing effect on glucose: suprabasal respiratory quotient and suprabasal carbohydrate oxidation were significantly (p < .05) lower under C12 administration than under LCT administration, with a difference of 0.024+/-0.015 in respiratory quotient (RQ) and a difference of 0.791+/-0.197 kJ/min in carbohydrate oxidation. In particular, carbohydrate oxidation increased by 54% over basal with LCT but only by 28% with C12 administration. RQ increased over basal by 5.8% with LCT but only by 3.0% with C12 administration.

CONCLUSIONS

These results show a fundamental metabolic difference between conventional lipids and DAs, which is the basis for a possible role of DAs in clinical nutrition. The fate of spared glucose is likely to be storage in glycogen form when dodecanedioic acid is made available as an energy source.