Allomyrina dichotoma larva extract attenuates free fatty acid-induced lipotoxicity in pancreatic beta cells

RESULTS@#The administration of ADLE to HFD-induced diabetic mice reduced the hyperplasia, 4-hydroxynonenal levels, and the number of apoptotic cells while improving the insulin levels compared to the HFD group. Treatment of INS-1 cells with palmitate reduced insulin secretion, which was attenuated by the ADLE treatment. Furthermore, the ADLE treatment prevented palmitate-induced cell death in INS-1 cells and isolated islets by reducing the apoptotic signaling molecules, including cleaved caspase-3 and PARP, and the Bax/Bcl2 ratio. ADLE also reduced the levels of reactive oxygen species generation, lipid accumulation, and nitrite production in palmitate-treated INS-1 cells while increasing the ATP levels. This effect corresponded to the decreased expression of inducible nitric oxide synthase (iNOS) mRNA and protein. @*CONCLUSIONS@#ADLE helps prevent lipotoxic beta-cell death in INS-1 cells and HFD-diabetic mice, suggesting that ADLE can be used to prevent or treat beta-cell damage in glucose intolerance during the development of diabetes.

Allomyrina dichotoma larva extract attenuates free fatty acid-induced lipotoxicity in pancreatic beta cells

RESULTS@#The administration of ADLE to HFD-induced diabetic mice reduced the hyperplasia, 4-hydroxynonenal levels, and the number of apoptotic cells while improving the insulin levels compared to the HFD group. Treatment of INS-1 cells with palmitate reduced insulin secretion, which was attenuated by the ADLE treatment. Furthermore, the ADLE treatment prevented palmitate-induced cell death in INS-1 cells and isolated islets by reducing the apoptotic signaling molecules, including cleaved caspase-3 and PARP, and the Bax/Bcl2 ratio. ADLE also reduced the levels of reactive oxygen species generation, lipid accumulation, and nitrite production in palmitate-treated INS-1 cells while increasing the ATP levels. This effect corresponded to the decreased expression of inducible nitric oxide synthase (iNOS) mRNA and protein. @*CONCLUSIONS@#ADLE helps prevent lipotoxic beta-cell death in INS-1 cells and HFD-diabetic mice, suggesting that ADLE can be used to prevent or treat beta-cell damage in glucose intolerance during the development of diabetes.

The effects of body mass index and body shape perceptions of South Korean adults on weight control behaviors; Correlation with quality of sleep and residence of place

BACKGROUND/OBJECTIVES: The obese population is rapidly increasing because of reduced physical activity and a Westernized diet; consequently, various chronic diseases are more prevalent. With the increasing interest in body shape and appearance, research on body shape perceptions and accompanying weight control behaviors are needed for healthy weight management.SUBJECTS/METHODS: A cross-sectional survey was conducted on randomly selected 536 (209 men and 327 women) aged 20 to 65 years. Body mass index (BMI), body-shape perception, weight control behavior, quality of sleep, and place of residence were collected using self-reported questionnaires. Multivariable logistic regression analysis was conducted using complex design in each groups. Collected data were analyzed using the SAS 9.4 statistical package, and the significance level was set at P < 0.05.RESULTS: When these two variables were divided into four groups, they were found to influence dieting attempts. People with abnormal weights who were dissatisfied with their body shapes attempted dieting 5.23 times more than those with healthy weights and satisfaction with their body shapes. Further, those with normal weights but dissatisfaction with their bodies attempted dieting 4.45 times more than those who were satisfied with their shapes. Subjects in their 20s attempted dieting 2.53 times more than those in their 30s and 40s, and female subjects attempted dieting 2.24 times more than male subjects.CONCLUSIONS: A correct perception of one's shape can be an important factor for dietary behavior, as body shape perceptions and dieting attempts are strongly related. Additionally, healthy weight management and nutrition education are important elements to incorporate into a weight control program aimed at preventing excessive weight control behaviors and promoting correct perceptions of body shape.

Protective effect of lycopene against cytokine-induced β-cell apoptosis in INS-1 cells / 한국영양학회지

PURPOSE: Lycopene, a carotenoid with anti-oxidant properties, occurs naturally in tomatoes and pink grapefruit. Although the beneficial effects of lycopene on various disorders have been established, little attention has been paid to the possible anti-diabetic effects of lycopene focusing on β-cells. Therefore, this study investigated the potential of lycopene to protect β-cells against apoptosis induced by a cytokine mixture. METHODS: For toxicity experiments, the cells were treated with 0.1 ~ 10 nM of lycopene, and the cell viability in INS-1 cells (a rat β-cell line) was measured using a MTT assay. To induce cytokine toxicity, the cells were treated with a cytokine mixture (20 ng/mL of TNFα+20 ng/mL of IL-1β) for 24 h, and the effects of lycopene (0.1 nM) on the cytokine toxicity were measured using the MTT assay. The expression levels of the apoptotic proteins were analyzed by Western blotting, and the level of intracellular reactive oxidative stress (ROS) was monitored using a DCFDA fluorescent probe. The intracellular ATP levels were determined using a luminescence kit, and mRNA expression of the genes coding for anti-oxidative stress response and mitochondrial function were analyzed by quantitative reverse-transcriptase PCR. RESULTS: Exposure of INS-1 cells to 0.1 nM of lycopene increased the cell viability significantly, and protected the cells from cytokine-induced death. Lycopene upregulated the mRNA and protein expression of B-cell lymphoma-2 (Bcl-2) and reduced the expression of the Bcl-2 associated X (Bax) protein. Lycopene inhibited apoptotic signaling via a reduction of the ROS, and this effect correlated with the upregulation of anti-oxidative stress response genes, such as GCLC, NQO1, and HO-1. Lycopene increased the mRNA expression of mitochondrial function-related genes and increased the cellular ATP level. CONCLUSION: These results suggest that lycopene reduces the level of oxidative stress and improves the mitochondrial function, contributing to the prevention of cytokine-induced β-cell apoptosis. Therefore, lycopene could potentially serve as a preventive and therapeutic agent for the treatment of type 2 diabetes.

Mechanistic insights into pancreatic beta-cell mass regulation by glucose and free fatty acids / 대한해부학회지

Pancreatic islets are responsible for blood glucose homeostasis. Reduced numbers of functional (insulin-secreting) beta-cells in pancreatic islets underlies diabetes. Restoration of the secretion of the proper amount of insulin is a goal. Beta-cell mass is increased by neogenesis, proliferation and cell hypertrophy, and is decreased by beta-cell death primarily through apoptosis. Many hormones and nutrients affect beta-cell mass, and glucose and free fatty acid are thought to be the most important determinants of beta-cell equilibrium. A number of molecular pathways have been implicated in beta-cell mass regulation and have been studied. This review will focus on the role of the principle metabolites, glucose and free fatty acid, and the downstream signaling pathways regulating beta-cell mass by these metabolites.

Exercise type and muscle fiber specific induction of caveolin-1 expression for insulin sensitivity of skeletal muscle

It is well known that exercise can have beneficial effects on insulin resistance by activation of glucose transporter. Following up our previous report that caveolin-1 plays an important role in glucose uptake in L6 skeletal muscle cells, we examined whether exercise alters the expression of caveolin-1, and whether exercise-caused changes are muscle fiber and exercise type specific. Fifity week-old Sprague Dawley (SD) rats were trained to climb a ladder and treadmill for 8 weeks and their soleus muscles (SOL) and extensor digitorum longus muscles (EDL) were removed after the last bout of exercise and compared with those from non-exercised animals. We found that the expression of insulin related proteins and caveolins did not change in SOL muscles after exercise. However, in EDL muscles, the expression of insulin receptor beta (IRbeta) and glucose transporter-4 (GLUT-4) as well as phosphorylation of AKT and AMPK increased with resistance exercise but not with aerobic exercise. Also, caveolin-1 and caveolin-3 increased along with insulin related proteins only in EDL muscles by resistance exercise. These results suggest that upregulation of caveolin-1 in the skeletal muscle is fiber specific and exercise type specific, implicating the requirement of the specific mode of exercise to improve insulin sensitivity.

Study of the Mechanism for the Growth Inhibitory Effects of Conjugated Linoleic Acid on Caco-2 Colon Cancer Cells

Conjugated linoleic acid (CLA) is a group of positional and geometric isomers of linoleic acid (LA) and exhibits anticarcinogenic activity in a variety of animal models. We have previously observed that CLA inhibited the growth of Caco-2 cells, a human colon adenocarcinoma cell line. The present study was performed to determine whether the growth inhibitory effect of CLA is related to change in secretion of IGF- II and/or IGF-binding proteins (IGFBPs) that have been shown to regulate Caco-2 cell proliferation by an autocrine mechanism. Cells were incubated in serum-free medium with various concentrations of CLA or linoleic acid (LA). Immunoblot analysis of 24-hours, serum-free, conditioned medium using a monoclonal anti-IGF-IIantibody revealed that Caco-2 cells secreted both mature 6,500 Mr and higher Mr forms of pro IGF-II. The levels of pro IGF-II and mature IGF-IIwere decreased by 43+/-2% and 53+/-6%, respectively by treatment with 50 micrometer CLA. LA slightly increased pro IGF- II levels. Results from Northern blot analysis showed that CLA decreased IGF-II mRNA levels at 50 micrometer concentration suggesting that CLA regulation of IGF-II protein expression occurs partly at the transcriptional level. Ligand blot analysis of conditioned media using 1251-IGF-II revealed that CLA slightly decreased IGFBP-2 levels and increased IGFBP-4 levels. We confirmed our previous results that CLA inhibited cell growth in a dose-dependent manner but LA slightly increased cell growth. Exogenous IGF-II mitigated the growth inhibitory effect of CLA. These results indicate that the growth inhibitory effect of CLA may be at least in part mediated by decreasing IGF-II and IGFBP-2 secretion and increasing IGFBP-4 secretion in Caco-2 cells.

Effects of Cyclooxygenase and Lipoxygenase Inhibitors on the Proliferation of Colon Cancer Cells and Their Production of Eicosanoids / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Epidemiological and laboratory studies suggest that nonsteroidal antiinflammatory drugs (NSAIDs) reduce the risk of colon cancer and that the inhibition of colon cancer is mediated through modulation of eicosanoid production. The present study examined the effect of cyclooxygenase (COX) and lipoxygenase (LOX) inhibitors on colon cancer cell growth and prostaglandin E(2) (PGE(2)) or leukotriene B(4) (LTB(4)) secretion by these cells. MATERIALS AND METHODS: The human colon adenocarcinoma cell lines, Caco-2 and HT-29 cells, were cultured in serum-free medium with various concentrations of indomethacin, piroxicam or esculetin in the presence of 0.15nM or 10nM linoleic acid. Cell number was estimated by MTT assay and PGE(2) and LTB(4) were analyzed by enzyme immunoassay. RESULTS: The NSAIDs inhibited cell proliferation in a concentration-dependent manner. However, the potency and efficacy of each drug varied in the two cell lines. In Caco-2 cells, the effect of esculetin was higher than that of indomethacin, and piroxicam had no effect. In HT-29 cells, only indomethacin significantly inhibited cell proliferation. All three agents inhibited PGE(2) secretion in a dose-dependent manner; the effect of indomethacin was highest and that of esculetin lowest. The secretion of LTB4 was increased by indomethacin and piroxicam but decreased by esculetin. The effects of these drugs on cell proliferation and eicosanoid secretion were not influenced by linoleic acid concentrations in the culture media. Neither exogenous PGE2 nor LTB4 affected cell proliferation. The results of Pearson correlation analyses revealed that changes in cell proliferation were somewhat related to both concentrations of NSAIDs in the culture medium and production of PGE(2) and LTB(4). CONCLUSION: The present data suggests that the anti-proliferative effect of NSAIDs may not be entirely attributed to changes in the production of PGE2 and/or LTB4 in the two colon cancer cell lines. These NSAIDs may inhibit cell proliferation largely independent of their ability to modulate eicosanoid synthesis.