Apostolos Perelas

Sonographic Assessment of Regional Adiposity

OBJECTIVE Various noninvasive imaging techniques, including CT, MRI, and sonography, have been used for accurate estimation of regional fat deposits. Among these techniques, sonography has attracted considerable attention because it combines safety, cost-effectiveness, and accuracy. The aim of this review is to present an overview of the studies in which sonographic techniques have been used to estimate visceral adiposity, the indexes derived, and the correlation between the indexes and metabolic and cardiovascular markers. CONCLUSION It is highly plausible that sonography will be used in clinical practice for the routine assessment of regional adiposity.

Effects of lipid-lowering drugs on adiponectin.

Adiponectin has been implicated in the pathogenesis of coronary heart disease. We review the literature describing the effect of lipid-lowering agents on adiponectin bioavailability. Statins exert variable effects that can be influenced by patient-dependent characteristics (i.e. diabetes or insulin resistance). Fibrates and especially niacin can raise adiponectin levels. The impact of plant sterols, ezetimibe and ω-3 fish oils on adiponectin in humans remains to be defined. There was no literature on whether resins can alter adiponectin levels. As far as mechanisms are concerned, statins enhance peroxisome proliferator-activator receptor (PPAR)-γ activation and have antioxidant or anti-inflammatory potential. Niacin, ω-3 fatty acids, plant sterols and bezafibrate primarily act by increasing PPAR-γ activity and possibly by reducing oxidative stress or inflammation. Both fibrates and ω-3 fish oils act as synthetic ligands for PPAR-α. Hypolipidaemic drugs can affect adiponectin bioavailability, although the impact depends on the individual drug administered and patient characteristics. However, with the exception of niacin, the results observed are not conclusive.

Heart dysfunction induced by choline-deficiency in adult rats: The protective role of l-carnitine

Choline is a B vitamin co-factor and its deficiency seems to impair heart function. Carnitine, a chemical analog of choline, has been used as adjunct in the management of cardiac diseases. The study investigates the effects of choline deficiency on myocardial performance in adult rats and the possible modifications after carnitine administration. Wistar Albino rats (n=24), about 3 months old, were randomized into four groups fed with: (a) standard diet (control-CA), (b) choline deficient diet (CDD), (c) standard diet and carnitine in drinking water 0.15% w/v (CARN) and (d) choline deficient diet and carnitine (CDD+CARN). After four weeks of treatment, we assessed cardiac function under isometric conditions using the Langendorff preparations [Left Ventricular Developed Pressure (LVDP-mmHg), positive and negative first derivative of LVDP were evaluated], measured serum homocysteine and brain natriuretic peptide (BNP) levels and performed histopathology analyses. In the CDD group a compromised myocardium contractility compared to control (P=0.01), as assessed by LVDP, was noted along with a significantly impaired diastolic left ventricular function, as assessed by (-) dp/dt (P=0.02) that were prevented by carnitine. Systolic force, assessed by (+) dp/dt, showed no statistical difference between groups. A significant increase in serum BNP concentration was found in the CDD group (P<0.004) which was attenuated by carnitine (P<0.05), whereas homocysteine presented contradictory results (higher in the CDD+CARN group). Heart histopathology revealed a lymphocytic infiltration of myocardium and valves in the CDD group that was reduced by carnitine. In conclusion, choline deficiency in adult rats impairs heart performance; carnitine acts against these changes.

Correlation between mesenteric fat thickness and serum apolipoproteins in patients with peripheral arterial occlusive disease

BackgroundVisceral fat possesses the most detrimental potential for cardiovascular morbidity through the release of adipokines, as well as metabolic and proinflammatory mediators, which adversely affect metabolic and vascular homeostasis. Among the different types of visceral adipose tissue, mesenteric fat is considered particularly detrimental, due to its close proximity to the portal circulation, affecting directly the liver, which is the main regulator of body metabolic homeostasis. Mesenteric fat can be reliably estimated using abdominal ultrasonography, the only available imaging method able to depict individual mesenteric leaves. Aim of the present study was to investigate the correlation of mesenteric fat thickness (MFT) with serum apolipoprotein levels in patients undergoing digital subtraction angiography in a single center.Methods35 male patients with peripheral arterial disease were examined. After careful examination of the periumbilical area, the mesenteric leaves were identified. The maximal distance between each pair of sequential leaves was measured, and the mean value of the three thickest leaves was determined as the mesenteric fat thickness. Six apolipoprotein fasting serum concentrations were measured using a Luminex proteomics platform (xMAP Multiplex immunoassay): apolipoprotein A-I (apoAI), apolipoprotein A-II (apoAII), apolipoprotein B (apoB), apolipoprotein C-II (apoCII), apolipoprotein C-III (apoCIII) and apolipoprotein E (apoE).ResultsMFT correlated with apoAII and apoB serum concentrations. The correlations with apoAII and apoB remained significant following correction for BMI. No correlations were noted between MFT and serum apoAI, apoCII, apoCIII or apoE levels before or after adjustment for BMI.ConclusionsOur study indicates that MFT is significantly correlated with the concentration of atherogenic low density lipoproteins particles, as well as with apoAII, a determinant of free fatty acids levels. No correlation was observed between mesenteric fat thickness and very low density lipoprotein or chylomicron particles concentration.

Effect of sibutramine on regional fat pads and leptin levels in rats fed with three isocaloric diets

AIM The aim of the study was to investigate: a) the differential effect of the three main macronutrients on food intake, fat depots and serum leptin levels and b) the impact of sibutramine on the above parameters in rats fed ad libitum with three isocaloric diets. METHODS Three groups of male Wistar rats (n = 63) were fed with a high fat diet (HFD), a high carbohydrate diet (HCD) or a high protein diet (HPD) for 13 weeks. In the last three weeks, each group was divided into three subgroups and received sibutramine (S) either at 5 mg/kg or 10 mg/kg, or vehicle. Food intake was measured daily during the last week of the experiment; perirenal and epididymal fat and fat/lean ratio were calculated and serum leptin was assayed. RESULTS HFD-fed rats demonstrated elevated food intake and higher regional fat depots. S at 10 mg/kg decreased food intake in the HFD and epididymal fat in the HCD group. S also reduced perirenal fat in the HCD and HPD groups. Leptin levels were higher in rats fed with either the HFD or the HPD compared to those fed with the HCD. Moreover, S at 10 mg/kg decreased serum leptin levels in the HPD group. CONCLUSIONS Results suggest a preferential effect of S on perirenal visceral fat and support the view that body fat loss is greater when its administration is accompanied by a HCD diet. No effect of S on leptin levels was found, besides that expected as a result of the decrease in body fat.

Immunohistochemical determination of the extracellular matrix modulation in a rat model of choline-deprived myocardium: the effects of carnitine

Choline has been identified as an essential nutrient with crucial role in many vital biological functions. Recent studies have demonstrated that heart dysfunction can develop in the setting of choline deprivation even in the absence of underlying heart disease. Matrix metalloproteinases (MMPs) are responsible for extracellular matrix degradation, and the dysregulation of MMP‐2 and MMP‐9 has been involved in the pathogenesis of various cardiovascular disorders. The aim of the study was to investigate the role of MMPs and their inhibitors (TIMPs), in the pathogenesis of choline deficiency‐induced cardiomyopathy, and the way they are affected by carnitine supplementation. Male Wistar Albino adult rats were divided into four groups and received standard or choline‐deficient diet with or without L‐carnitine in drinking water (0.15% w/v) for 1 month. Heart tissue immunohistochemistry for MMP‐2, MMP‐9, TIMP‐1, and TIMP‐2 was performed. Choline deficiency was associated with suppressed immunohistochemical expression of MMP‐2 and an increased expression of TIMP‐2 compared to control, while it had no impact on TIMP‐1. MMP‐9 expression was decreased without, however, reaching statistical significance. Carnitine did not affect MMP‐2, MMP‐9, TIMP‐1 or TIMP‐2 expression. The pattern of TIMP and MMP modulation observed in a choline deficiency setting appears to promote fibrosis. Carnitine, although shown to suppress fibrosis, does not seem to affect MMP‐2, MMP‐9, TIMP‐1 or TIMP‐2 expression. Further studies will be required to identify the mechanism underlying the beneficial effects of carnitine.

Effect of Isocaloric Diets and Sibutramine on Food Intake, Body Mass Variation and Serum TNF-α Levels in Rats

Background/Aim: The effect of isocaloric diets and sibutramine on dietary behaviour and TNF-α is poorly understood. The aim of the study was to investigate the effects of isocaloric diets and sibutramine on food intake, body mass variation and serum TNF-α in free-feeding rats. Methods: Three groups of male Wistar rats (n = 63) were fed a high-fat diet, high-carbohydrate diet or high-protein diet for 13 weeks. In the last 3 weeks, each group was divided into 3 subgroups. Each subgroup received sibutramine 5 mg/kg, sibutramine 10 mg/kg or vehicle. Food intake was measured daily during the last week of the experiment; serum TNF-α was assayed and the body weight increasing rate was calculated. Results: The high-fat diet was associated with increased food intake, a greater weight gain ratio and increased TNF-α levels. Sibutramine treatment did not affect the dietary behaviour of high-protein- or high-carbohydrate-fed rats, while it significantly attenuated the daily food intake and body weight gain rate in the high-fat group, at the dose of 10 mg/kg. TNF-α levels were not affected by sibutramine. Conclusions: High-fat feeding was associated with an increase in daily food intake, TNF-α levels and body weight gain rate, as well as with enhanced responsiveness to the anorectic effects of sibutramine. However, sibutramine did not affect TNF-α.

Two foreign bodies embedded in the intraventricular septum: A case report

A 23-year old male was presented at the outpatient clinic of our department reporting that he had been subjected to insertion of foreign bodies in his chest. Physical examination was unremarkable. Imaging studies revealed the presence of two bodies in the subcutaneous tissue of the anterior chest wall and two needle-shaped intramyocardial bodies that were impacted in the intraventricular septum. Due to late appearance, the position, and because of the absence of symptoms, it was decided that the patient should be managed conservatively. Today, five years after the incident, the patient remains asymptomatic and he is followed-up regularly.