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.

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.

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.

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.

VO2, VCO2, 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 O(2) consumption (Vo(2)), CO(2) production (Vco(2)), and respiratory quotient (RQ) in humans, enabling long term (24-h) observation under free-living conditions. Computation of Vo(2) and Vco(2) 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 Vo(2) and Vco(2) 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 Vo(2) and Vco(2) estimates. Consequently, the accuracy of the computed RQ is also highly improved (0.3 x 10(-4) vs. 800 x 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.

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.

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.

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.

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).

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.

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.

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.

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).

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.

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.