Tag Archives: obesity

The effect of N-stearoylethanolamine on adipocytes free cholesterol content and phospholipid composition in rats with obesity-induced insulin resistance

O. S. Dziuba, Ie. A. Hudz, H. V. Kosiakova, T. M. Horid’ko, V. M. Klimashevsky, N. M. Hula

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: oksana.dziuba86@gmail.com

Obesity induces molecular changes that promote associated disorders, such as insulin resistance (IR) and type 2 diabetes. Low insulin sensitivity occurs primarily due to defects in the pathway of insulin action in target tissues, and there is a hypothesis that IR may originate in adipose tissue and is followed by dyslipidemia. In this study using methods of thin-layer and gas-liquid chromatography we investigated free cholesterol content and phospholipid composition of adipocytes of obesity-induced IR rats and its changes induced by the N-stearoylethanolamine (NSE) administration. The results we obtained demonstrated that free cholesterol content significantly increased in adipocytes of IR rats compared to control. The analysis of phospholipid composition indicated a reduction of phosphatidylcholine and the total content of phosphatidylinositol with phosphatidylserine, whereas the content of lysophosphatidylcholine, sphingomyelin and phosphatidylethanolamine increased in IR group compared to control. NSE administration caused a statistically significant decrease in total cholesterol level and had a considerable effect on normalization of individual phospholipids content. As far as NSE administration caused a statistically significant decrease in free cholesterol level and had a considerable effect on normalization of individual phospholipids content of adipocytes, we can consider NSE as a prospective compound worthy more complex investigation of its action under the pathological conditions.

Evaluation of metallothioneins, oxidative stress and signs of cytotoxicity in young obese women

H. I. Falfushynska, O. I. Horyn, V. V. Khoma, G. V. Tereshchuk,
D. V. Osadchuk, N. I. Rusnak, O. B. Stoliar

Ternopil Volodymyr Hnatiuk National Pedagogical University, Ukraine;
e-mail: falfushynska@tnpu.edu.ua

Obesity is rapidly increasing all over the world and pretends to be the global medical and social problem. Thus, the understanding of early signs of obesity and suitable biomarkers is urgently needed for developing an adequate strategy of the obesity prevention and a decrease in its growth rate. The parameters of the lipids’ metabolism and oxidative stress, metallothioneins and signs of cytotoxicity have been investigated in blood samples of young obese women (O-group, 32 < Body Mass Index (BMI) < 37). With regard to persons of O-group they had higher catalase activity (by 435%), level of reactive oxygen species (by 129%), level of oxidised glutathione (by 55%), lipid peroxidation (by 26%) and protein carbonyls (by 345%) in the blood, when compared with control. The obesity was accompanied by an increase in concentration of metallothioneins which have a partial tread effect on radical processes and reduce manifestations of oxidative damage to biomolecules in obese patients. The obese women had the signs of cytotoxicity as higher lactate dehydrogenase activity (by 387%) and DNA fragmentation (by 42%). The principal component analysis revealed the set of biological traits which describes the obesity progress and it included metallothioneins, parameters of oxidative stress, cytotoxicity, BMI and a concentration of low density lipoproteins and total cholesterol. The BMI was in a good correlation with parameters of the lipid metabolism, oxidative injury and cytotoxicity (r > |0.73|, P < 0.001).

Blood coagulation and aortic wall integrity in rats with obesity-induced insulin resistance

O. S. Dziuba1, V. O. Chernyshenko1, Ie. A. Hudz1, L. O. Kasatkina1, T. M. Chernyshenko1,
P. P. Klymenko2, H. V. Kosiakova1, T. M. Platonova1, N. M. Hula1, E. V. Lugovskoy1

1Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: oksana.dziuba86@gmail.com;
2State Institute of Gerontology of AMS of Ukraine, Kyiv

Obesity is an important factor in pathogenesis of disorders caused by chronic inflammation. Diet-induced obesity leads to dyslipidemia and insulin resistance (IR) that in turn provoke the development of type 2 diabetes and cardiovascular diseases. Thus, the aim of this work was to investigate the possible pro-atherogenic effects in the blood coagulation system and aortic wall of rats with obesity-induced IR. The experimental model was induced by a 6-month high-fat diet (HFD) in white rats. Blood samples were collected from 7 control and 14 obese IR rats. Prothrombin time (PT) and partial activated thromboplastin time (APTT) were performed by standard methods using Coagulometer Solar СТ 2410. Fibrinogen concentration in the blood plasma was determined by the modified spectrophotometric method. Levels of protein C (PC), prothrombin and factor X were measured using specific chromogenic substrates and activa­ting enzymes from snake venoms. Platelet aggregation was measured and their count determined using Aggregometer Solar AP2110. The aorta samples were stained by hematoxylin and eosin according to Ehrlich. Aortic wall thickness was measured using morphometric program Image J. Statistical analysis was performed using Mann-Whitney U Test. The haemostasis system was characterized by estimation of the levels of individual coagulation factors, anticoagulant system involvement and platelet reactivity. PT and APTT demonstrated that blood coagulation time strongly tended to decrease in obese IR rats in comparison to the control group. It was also detec­ted that 30% of studied obese IR rats had decreased factor X level, 40% had decreased level of prothrombin whereas fibrinogen concentration was slightly increased up to 3 mg/ml in 37% of obese IR rats. A prominent decrease of anticoagulant PC in blood plasma of obese rats was detected. Obese IR rats also had increased platelet count and higher rate of platelet aggregation in comparison to control animals. Histological analysis identified the disruption of aorta endothelium and tendency for the thickening of the aorta wall in the group with obesity-induced IR compared to the group of control rats. Changes of individual coagulation factors were assumed as the evidence of imbalance in the blood coagulation system. Increase of fibrinogen level, drop in PC concentration and pathological platelet reactivity were taken to corroborate the development of low-grade inflammation in obese IR rats. Instant generation of small amounts of thrombin in their blood plasma is expected. Since the aorta morphology assay detected the trend of its wall to thicken and the emergence of disruptions, we assumed there were initial stages of atherosclerosis and the danger of developing atherothrombosis. We detected an increase of blood coagulability and changes in aorta morphology in rats with obesity-induced IR which we assume indicate early development of atherosclerosis.

The effect of N-stearoylethanolamine on cholesterol content, fatty acid composition and protein carbonylation level in rats with alimentary obesity-induced insulin resistance

O. V. Onopchenko, G. V. Kosiakova, E. F. Meged,
V. M. Klimashevsky, N. M. Hula

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: onop.89.av@mail.ru

The effect of N-stearoylethanolamine (NSE) on liver free fatty acid composition, cholesterol content and carbonylated protein level in rats with obesity-induced insulin resistance (IR) was studied in the work. The experimental insulin resistance was induced by prolonged high fat diet (58% of energy derived from fat) for 6 months combined with one injection of low-dose (15 mg/kg) of streptozotocin. The lipid assay showed a rise in liver free cholesterol content and a significant reduction in cholesterol esters level. Analyzing liver fatty acid composition, a decrease in polyunsaturated of fatty acid (PUFA) level and an increase in monounsaturated fatty acid (MUFA) content was found. Fatty acid imbalance with high content of MUFA was associated with elevated level of protein carbonylation.  The NSE administration (50 mg/kg of body weight) for 2 weeks decreased free cholesterol content, increased cholesterol esters level and reduced free oleic fatty acid content in the liver of rats with IR. The effect of NSE on lipid imbalance led to a decrease in protein carbonylation level that may result in improvement of transmembrane protein function under obesity-induced insulin resistance state.

The effect of N-stearoylethanolamine on liver phospholipid composition of rats with insulin resistance caused by alimentary obesity

O. V. Onopchenko, G. V. Kosiakova, T. M. Goridko, V. M. Klimashevsky, N. M. Hula

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: onop.89.av@mail.ru

We used alimentary obesity-induced insulin resistance (IR) model in rats to investigate the influence of N-stearoylethanolamine on the content of phospholipids and their fatty acid composition.  Our results show that prolonged high-fat diet triggers considerable aberrations in the composition of main phospholipids in the liver and can be one of the causes of IR in rats. In particular, the increase of phosphatidylcholine, phosphatidylethanolamine and significant decrease of other phospholipids: lysophosphatidylcholine, lysophosphatidylethanolamine, sphingomyelin, phosphatidylinositol, phosphatidylserine and diphosphaglicerol were observed. The levels of monounsaturated (erucic, nervonic, oleic) and polyunsaturated (eicosatrienoic, docosatrienoic, arachidonic) fatty acids were increased; meanwhile the content of diunsaturated acids was decreased.  The NSE administration (50 mg/kg of body weight) caused restoration of the phospholipids content in the liver of rats with diet-induced IR that highly correlated with the decrease in plasma insulin level and the improvement of insulin sensitivity. Moreover, the effect of NSE was accompanied by the normalization of fatty acids composition of phospholipids that could be related to modulating influen­ce of NSE on the activity of the main fatty acid desaturases.  It is known that the imbalance in phospholipid composition of the rat liver causes substantial metabolic alterations that are associated with the development of IR. Accordingly, the compensations of the imbalance by NSE can help to restore insulin sensitivity, inhibit the development of obesity, IR and type 2 diabetes.

The effect of N-stearoylethanolamine on plasma lipid composition in rats with experimental insulin resistance

O. V. Onopchenko, G. V. Kosiakova, V. M. Klimashevsky, N. M. Hula

Palladin Institute of Biochemistry, National Academy
of Sciences of Ukraine, Kyiv;
e-mail: onop.89.av@mail.ru

A model of insulin resistance (IR), induced by prolonged high fat diet with high content of saturated fats was used to investigate the effect of N-stearoylethanolamine (NSE) on the composition of free fatty acids (FFA), plasma lipoprotein spectrum and content of proinflammatory cytokine TNFα in rats. The results of this work showed a rise in the content of monounsaturated fatty acids (18:1 n-9) and a reduction in the level of polyunsaturated fatty acids (20:4 n-6) in plasma of rats with experimental IR. These findings are accompanied by the increased TNFα production and significant changes in plasma lipoprotein profile of rats with the fat overload. Particularly, a decreased high-density lipoprotein (HDL) cholesterol level and increased low-density (LDL) and very low-density lipoprotein (VLDL) cholesterol level were detected. The NSE administration to obese rats with IR restored the content of mono- and polyunsaturated FFA, increased HDL cholesterol content and reduced LDL cholesterol level. In addition, the IR rats treated with NSE showed normalization in the serum TNFα level. Our results showed the restoration of plasma lipid profile under NSE administration in rats with obesity-induced IR. Considering the fact that plasma lipid composition displays the lipid metabolism in general, the NSE actions may play a significant role in the prevention of IR-associated complications.