Banting lecture 2001: dysregulation of fatty acid metabolism in the etiology of type 2 diabetes

Acute Effects of Cinnamon Spice on Post-prandial Glucose and Insulin in Normal Weight and Overweight/Obese Subjects: A Pilot Study

Clinical studies and meta-analyses have supported the notion that consuming cinnamon spice long term can have beneficial effects in individuals with normal glucose homeostasis and varying degrees of glucose intolerance including type 2 diabetes. The objective of this study was to evaluate the acute effect of cinnamon on the post-prandial responses to a typical American breakfast in normal and overweight/obese participants (ClinicalTrials.gov registration No. NCT04686552). The consumption of a single dose of 6 g of cinnamon added to oatmeal prepared with milk resulted in a significant reduction of one of our primary outcomes post-prandial insulin response (niAUC_0−180min) in overweight/obese participants compared to control consuming breakfast without cinnamon. We also performed exploratory analysis of secondary outcomes. In normal weight participants, we observed a decrease of post-prandial glucagon response (niAUC_0−180min and glucagon levels at 60–120 min) and C-peptide response (30 min) comparing breakfast with to without cinnamon. Cinnamon consumption did not change post-prandial glycemic response in normal weight participants, but increased 60 min post-prandial glucose in overweight/obese participants compared to control. In summary, cinnamon consumption differentially affected post-prandial hormonal responses in normal and overweight/obese participants.

The herbal extract ALS-L1023 from Melissa officinalis reduces weight gain, elevated glucose levels and β-cell loss in Otsuka Long-Evans Tokushima fatty rats

ETHNOPHARMACOLOGICAL RELEVANCE

Melissa officinalis L. (Labiatae; lemon balm) is a traditional medicinal plant with hypoglycemic and hypolipidemic effects; however, how it imparts its beneficial effects remains unclear. We thus hypothesized that the herbal extract ALS-L1023, isolated from Melissa officinalis, inhibits obesity and diabetes, and tested our hypothesis using Otsuka Long-Evans Tokushima fatty (OLETF) rats, which are an established animal model of type 2 diabetes.

MATERIALS AND METHODS

In this study, 28-week-old OLETF rats were fed a high-fat diet for 4 weeks to induce a marked impairment of the insulin response and were treated with or without ALS-L1023. Subsequently, the variables and determinants of glucose metabolism and pancreatic function were assessed via blood analysis, histology, immunohistochemistry, and real-time polymerase chain reaction.

RESULTS

The administration of ALS-L1023 resulted in a weight reduction without changes in food intake. It also markedly inhibited hyperglycemia and hypoinsulinemia, and restored β-cell mass that was severely impaired in OLETF rats. There was a decrease in lipid accumulation in the liver and skeletal muscle of the obese rats after treatment with ALS-L1023. Concomitantly, there was an increase in the expression levels of fatty acid-oxidizing enzymes (AMPKα2, ACOX, MCAD, and VLCAD) in the liver and skeletal muscle after ALS-L1023 treatment. Furthermore, ALS-L1023 attenuated the pancreatic inflammation including the infiltration of CD68-positive macrophages and mast cells, in addition to attenuating the expression of inflammatory factors (IL-6 and CD68).

CONCLUSIONS

These results suggest that treatment with ALS-L1023 may reduce weight gain, elevated glucose levels, and β-cell loss, by changing the expression of fatty acid-oxidizing enzymes in the liver and skeletal muscle, including inflammatory factors in the pancreas. These findings indicate that ALS-L1023 may be an effective therapeutic strategy to treat human obesity and type 2 diabetes.

Pioglitazone corrects dysregulation of skeletal muscle mitochondrial proteins involved in ATP synthesis in type 2 diabetes

CONTEXT

In this study, we aimed to identify the determinants of mitochondrial dysfunction in skeletal muscle (SKLM) of subjects with type 2 diabetes (T2DM), and to evaluate the effect of pioglitazone (PIO) on SKLM mitochondrial proteome.

METHODS

Two different groups of adults were studied. Group I consisted of 8 individuals with normal glucose tolerance (NGT) and 8 with T2DM, subjected to SKLM mitochondrial proteome analysis by 2D-gel electrophoresis followed by mass spectrometry-based protein identification. Group II included 24 individuals with NGT and 24 with T2DM, whose SKLM biopsies were subjected to immunoblot analysis. Of the 24 subjects with T2DM, 20 were randomized to receive placebo or PIO (15 mg daily) for 6 months. After 6 months of treatment, SKLM biopsy was repeated.

RESULTS

Mitochondrial proteomic analysis on Group I revealed that several mitochondrial proteins involved in oxidative metabolism were differentially expressed between T2DM and NGT groups, with a downregulation of ATP synthase alpha chain (ATP5A), electron transfer flavoprotein alpha-subunit (ETFA), cytochrome c oxidase subunit VIb isoform 1 (CX6B1), pyruvate dehydrogenase protein X component (ODPX), dihydrolipoamide dehydrogenase (DLDH), dihydrolipoamide-S-succinyltransferase (DLST), and mitofilin, and an up-regulation of hydroxyacyl-CoA-dehydrogenase (HCDH), 3,2-trans-enoyl-CoA-isomerase (D3D2) and delta3,5-delta2,4-dienoyl-CoA-isomerase (ECH1) in T2DM as compared to NGT subjects. By immunoblot analysis on SKLM lysates obtained from Group II we confirmed that, in comparison to NGT subjects, those with T2DM exhibited lower protein levels of ATP5A (-30%, P = 0.006), ETFA (-50%, P = 0.02), CX6B1 (-30%, P = 0.03), key factors for ATP biosynthesis, and of the structural protein mitofilin (-30%, P = 0.01). T2DM was associated with a reduced abundance of the enzymes involved in the Krebs cycle DLST and ODPX (-20%, P ≤ 0.05) and increased levels of HCDH and ECH1, enzymes implicated in the fatty acid catabolism (+30%, P ≤ 0.05). In subjects with type 2 diabetes treated with PIO for 6 months we found a restored SKLM protein abundance of ATP5A, ETFA, CX6B1, and mitofilin. Moreover, protein levels of HCDH and ECH1 were reduced by -10% and - 15% respectively (P ≤ 0.05 for both) after PIO treatment.

CONCLUSION

Type 2 diabetes is associated with reduced levels of mitochondrial proteins involved in oxidative phosphorylation and an increased abundance of enzymes implicated in fatty acid catabolism in SKLM. PIO treatment is able to improve SKLM mitochondrial proteomic profile in subjects with T2DM.

Associations Between Serum Free Fatty Acid Levels and Incident Diabetes in a 3-Year Cohort Study

PURPOSE

High circulating free fatty acid (FFA) is associated with the development of diabetes. This study was designed to evaluate longitudinal associations between FFA levels, changes in FFA levels, and mean FFA levels and incident diabetes.

PARTICIPANTS AND METHODS

This 3-year cohort study was conducted in Ningyang between 2011 and 2014. Serum FFA, fasting blood glucose (FPG), 2-hour postprandial blood glucose (2hPG), and glycosylated hemoglobin (HbA1c) levels were measured at baseline and at the end of follow-up. A multivariate stepwise logistic regression model was used to evaluate associations between serum FFA levels in various groups and the risk of incident diabetes.

RESULTS

Of the 2905 individuals without baseline diabetes, 290 developed diabetes by the 3-year follow-up. With increasing baseline FFA levels, the mean FPG, 2hPG, and HbA1c levels, and the prevalence of diabetes at the end of follow-up increased. The trend of FPG and HbA1c increase was not statistically significant. Higher baseline FFA levels were not significantly associated with greater risk of incident diabetes. However, longitudinal changes in serum FFA levels showed that individuals with serum FFA levels from normal to high (OR = 2.956, 95% CI: 2.089-4.184) or from high to high (OR = 3.343, 95% CI: 2.300-4.857) had greater risk of incident diabetes compared with those with normal to normal FFA levels. Similarly, individuals with ΔFFA ≥ 0 mmol/L (OR = 1.762, 95% CI: 1.373-2.262) or high mean serum FFA levels (OR = 2.120, 95% CI: 1.620-2.775) were at higher risk of incident diabetes than those with ΔFFA < 0 mmol/L or normal mean serum FFA levels.

CONCLUSION

The longitudinal status of serum FFA levels, including chronic increases and sustained high levels, was more closely associated with high risk of incident diabetes than was high baseline FFA levels.

Anti-obesity effects of Grifola frondosa through the modulation of lipid metabolism via ceramide in mice fed a high-fat diet

Obesity is characterized by massive fat deposition and is related to a series of metabolic complications, such as insulin resistance (IR) and steatohepatitis. Grifola frondosa (GF) is a basidiomycete fungus and a source of various nutritional ingredients related to human health. In this study, after a systematic analysis of its nutritional ingredients, GF was administered to mice fed a high-fat diet (HFD) to investigate its effects on lipid metabolism. In HFD-fed mice, GF significantly controlled the body weight, blood glucose and related organ indices, and effectively counteracted hyperlipidemia and IR triggered by the HFD. GF administration efficiently alleviated hepatic steatosis and adipocyte hypertrophy, and regulated alanine aminotransferase and aspartate aminotransferase in the liver. An analysis of the intestinal microflora showed that GF reversed obesity-induced dysbiosis by affecting the relative abundance of certain bacteria, reducing lipopolysaccharide production and regulating the superpathway of heme biosynthesis associated with inflammation. According to the results of lipidomics, ceramide, a metabolite related to inflammation and IR, was found to be dysregulated in HFD-fed mice. However, GF regulated the ceramide levels and restored lipid metabolism via the suppression of Toll-like receptor 4/nuclear factor kappa-B signaling, which is involved in inflammation and IR. This study provides the experimental basis for the application of GF as an agent for obesity.

Periodontitis and identification of undiagnosed hyperglycemia

Abstract Introduction Individuals with pre-diabetes have altered glycemic levels, are generally asymptomatic, and are at increased risk for developing type 2 diabetes mellitus. Objective Identify the prevalence of periodontal individuals with undiagnosed hyperglycemia and associated impact factors. Material and method Fifty-six patients with periodontitis and without diabetes self-report, users of dental clinic services at Federal University of Juiz de Fora were included in this research, during one year and a half of experimental evaluation. Socioeconomic and demographic data, anthropometric patterns, fasting capillary blood glucose, and complete periodontal examination (six sites per tooth) were evaluated. Result The sample consisted of 58.9% female, mean age 53 years old, 58.9% obese/overweight and 45.3% had a low level of education. A total of 28.6% (n=16) participants had undiagnosed hyperglycemia (between 100 to 160 mm / dL), of which 81.3% were obese/overweight, 25% were smokers, 56.3% reported having a history of diabetes in the family, 93.8% had a family income up to 2 brazilian´s minimum wages. BMI values were higher in the group of patients with hyperglycemia (29.8 ± 5.7, p = 0.03) compared to the group without hyperglycemia (26.6 ± 5.6). Patients with hyperglycemia had a greater number of sites with clinical attachment loss (CAL) between 4 and 6 mm (p = 0.04) when compared with the normoglycemic group. Conclusion Undiagnosed CAL attachment loss between 4 and 6 mm due to periodontitis than normoglycemic individuals.

Pathways Enrichment Analysis of Gene Expression Data in Type 2 Diabetes

Profiling genome-wide transcriptional changes with advanced high-throughput transcriptional profiling techniques has led to a revolution in biomedical science. It has been challenging to handle the massive data generated by these techniques and draw meaningful conclusions from it. Therefore, computational biologists have developed a number of innovative methods of varying complexity and effectiveness to analyze such complex data. Over the past decade, rich information in pathway repositories has attracted and motivated researchers to incorporate such existing biological knowledge into computational analysis tools to develop what is known as pathway enrichment analysis tools. This chapter describes a new sophisticated pathway enrichment tool that exploits topology of pathway as well as expression of significantly changed genes to identify biologically significant pathways for high-dimensional gene expression datasets. Also, we demonstrate the use of this tool to analyze gene expression data from a type 2 diabetes dataset to identify a list of significantly enriched metabolic pathways.

The Influence of Physical Activity on the Bioactive Lipids Metabolism in Obesity-Induced Muscle Insulin Resistance

High-fat diet consumption and lack of physical activity are important risk factors for metabolic disorders such as insulin resistance and cardiovascular diseases. Insulin resistance is a state of a weakened response of tissues such as skeletal muscle, adipose tissue, and liver to insulin, which causes an increase in blood glucose levels. This condition is the result of inhibition of the intracellular insulin signaling pathway. Skeletal muscle is an important insulin-sensitive tissue that accounts for about 80% of insulin-dependent glucose uptake. Although the exact mechanism by which insulin resistance is induced has not been thoroughly understood, it is known that insulin resistance is most commonly associated with obesity. Therefore, it is believed that lipids may play an important role in inducing insulin resistance. Among lipids, researchers’ attention is mainly focused on biologically active lipids: diacylglycerols (DAG) and ceramides. These lipids are able to regulate the activity of intracellular enzymes, including those involved in insulin signaling. Available data indicate that physical activity affects lipid metabolism and has a positive effect on insulin sensitivity in skeletal muscles. In this review, we have presented the current state of knowledge about the impact of physical activity on insulin resistance and metabolism of biologically active lipids.

Metformin downregulates miR223 expression in insulin-resistant 3T3L1 cells and human diabetic adipose tissue

AIMS AND DESIGNS

Metformin, an anti-diabetic drug, is the first line medication for the treatment of type 2 diabetes mellitus and some studies show its relationship with micro-RNAs. This study set up to determine the effect of metformin on miR223 expression and content of AKT/GLUT4 proteins in insulin resistant signaling in 3T3L1 cells and adipocyte of human diabetic patients.

MATERIALS AND METHODS

Subcutaneous adipose tissues were taken from newly diagnosed diabetic patients (HOMA-IR > 1.8), before and after three months treatment with 500 mg of metformin twice a day. Cellular homogenate was prepared and miR223 expression and AKT/GLUT4 protein expression were determined by quantitative real-time PCR and western blotting. The results were compared to insulin resistant 3T3L1 adipocytes that were treated with 10 mM Metformin.

RESULTS

MiR223 expression was significantly overexpressed both in insulin-resistant 3T3L1 adipocytes compared to non-insulin resistant adipocytes and in human diabetic adipose tissue, compared to non-diabetics (P value < 0.01). Metformin treatment downregulated miR223 expression in both adipocytes and human diabetic adipose tissue. In contrast the IRS/PI3-K/AKT pathway signaling components, Akt and GLUT4 increased in insulin-resistant 3T3L1 adipocytes and human diabetic adipose tissue after three months of metformin treatment.

CONCLUSIONS

Metformin reduced insulin resistance in adipocytes by reduction of miR223 expression and improving of IRS/Akt/GLUT4 signaling pathways. Plasma miR223 expression of human diabetic patients was reduced by metformin treatment. These results point to a novel mechanism of miR223 in insulin resistance.

Protective Effects of Moderate Intensity Static Magnetic Fields on Diabetic Mice

The purpose of this study was to investigate the effects of moderate-intensity static magnetic field (SMF) on diabetic mice. We studied the effects of SMF on blood glucose of normal mice by starch tolerance and glucose tolerance tests. Then, we evaluated the effects of SMF on blood glucose of diabetic mice by establishing alloxan-induced type 1 diabetic mice and high-fat diet + streptozotocin (STZ)-induced type 2 diabetic mice. The results showed that different magnetic field intensities and blank control did not affect the blood glucose of normal mice. After starch and glucose administration, different magnetic fields could improve the glucose tolerance of normal mice, and this was obvious in the 600 mT group. In the experiment of type 1 diabetic mice induced by alloxan, the results showed that different magnetic field intensities could improve the starch tolerance of mice, and that in the 400 mT group was obvious. In the experiment of type 2 diabetic mice induced by a high-fat diet + STZ, the 400 mT group could reduce food intake and water consumption in the later period. The 600 mT group could improve the starch tolerance of mice. The 400 and 600 mT groups could reduce fasting blood glucose. At the same time, total cholesterol and triglyceride decreased in different magnetic field intensities, and the 600 mT group could significantly increase the serum insulin content of mice. In summary, the results of this study suggest that SMF has a protective role in diabetic mice. Bioelectromagnetics. © 2020 Bioelectromagnetics Society.

Longitudinal changes in insulin resistance in children with epilepsy on ketogenic diet: Prevalence and risk factors

INTRODUCTION

The aim of the study was to evaluate the incidence of insulin resistance (IR) and the associated risk factors in children with epilepsy on a ketogenic diet (KD).

METHODS

This longitudinal cohort study analyzed data of children with epilepsy on KD. Insulin resistance was assessed using the homeostasis model assessment of insulin resistance (HOMA-IR). The HOMA-IR value, fasting serum insulin levels, fasting glucose (FG) levels, and lipid profiles were measured before the initiation of the KD and at 6- to 12-month intervals.

RESULTS

A total of 28 children were enrolled. The median age at the initiation of KD was 2.7 ± 2.4 years, and the median follow-up duration was 2.1 ± 1.4 years. The median HOMA-IR (HOMA-IR-1) value before the initiation of KD was 1.2 ± 0.2, which significantly increased to 1.8 ± 0.3 at the last follow-up (HOMA-IR-2; ∆HOMA-IR = 0.6 ± 0.3, p < 0.001). The following factors were associated with patients with higher HOMA-IR-2 values (≥1.9): younger age at seizure onset (0.3 ± 0.2 years, p < 0.001), at the initiation of antiepileptic drugs (AEDs; 0.3 ± 0.3 years, p < 0.001), and at the initiation of KD (1.3 ± 0.5 years, p < 0.001) and higher serum alanine transaminase (ALT; 84.0 ± 17.8 U/L, p = 0.022), total cholesterol (TC; 245.0 ± 20.1 mg/dL, p = 0.001), low-density lipoprotein cholesterol (LDL-C, 103.0 ± 6.7 mg/dL, p = 0.003), and triglyceride (387.0 ± 28.8 mg/dL, p < 0.001) levels. Multivariate regression analysis revealed that the age at seizure onset (p = 0.002), at initiation of AEDs (p = 0.021), and at initiation of KD (p = 0.022) and serum levels of LDL-C (p = 0.012) and triglycerides (p = 0.026) were associated with a significantly high HOMA-IR-2 value.

CONCLUSION

Close monitoring of serum lipids levels, especially at younger age, may aid in detecting exacerbation of IR.

Pubertal maturation and weight status are associated with dyslipidemia among children and adolescents in Northwest China

Dyslipidemia is one of major risk factors for cardiovascular disease. The early detection and treatment of dyslipidemia can reduce cardiovascular disease risk. A cross-sectional study was carried out in Ningxia, China to determine the prevalence of dyslipidemia and its association with body mass index (BMI) and pubertal stage. A total of 1783 students were selected from middle schools and high schools in September 2014 using stratified random cluster sampling. Serum triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were measured by using MOL-300 automatic biochemical analyzer with associated kits. The prevalence of adolescents with one abnormal serum lipid component was 43.2% and was significantly different across three pubertal stages (p < 0.0001). The abnormal rates of HDL-C and TG increased as the students maturated through the early, middle, and late stages of puberty (all p < 0.0001). Similar results were obtained when separate analyses were performed for boys and girls. In linear regression analysis, BMI was positively associated with serum levels of TC, LDL-C, and TG, but inversely associated with serum levels of HDL-C after the adjustment for age, sex, and race. In multivariable logistic regression analysis, obesity was associated with an increased risk of developing high TC, while pubertal maturation was associated with an elevated risk of experiencing low HDL-C and high TG (all p < 0.05). In conclusions, dyslipidemia is common in an adolescent population of Northwest China and its prevalence rates substantially vary with weight status and pubertal stage.

Effects of Anthocyanin Extracts from Bilberry (Vaccinium myrtillus L.) and Purple Potato (Solanum tuberosum L. var. 'Synkeä Sakari') on the Plasma Metabolomic Profile of Zucker Diabetic Fatty Rats

This study compared the effects of the nonacylated and acylated anthocyanin-rich extracts on plasma metabolic profiles of Zucker diabetic fatty rats. The rats were fed with the nonacylated anthocyanin extract from bilberries (NAAB) or the acylated anthocyanin extract from purple potatoes (AAPP) at daily doses of 25 and 50 mg/kg body weight for 8 weeks. ¹H NMR metabolomics was used to study the changes in plasma metabolites. A reduced fasting plasma glucose level was seen in all anthocyanin-fed groups, especially in the groups fed with NAAB. Both NAAB and AAPP decreased the levels of branched-chain amino acids and improved lipid profiles. AAPP increased the glutamine/glutamate ratio and decreased the levels of glycerol and metabolites involved in glycolysis, suggesting improved insulin sensitivity, gluconeogenesis, and glycolysis. AAPP decreased the hepatic TBC1D1 and G6PC messenger RNA level, suggesting regulation of gluconeogenesis and lipogenesis. This study indicated that AAPP and NAAB affected the plasma metabolic profile of diabetic rats differently.

Study on structure characterization of pectin from the steamed ginseng and the inhibition activity of lipid accumulation in oleic acid-induced HepG2 cells

Two acid polysaccharides were obtained from steamed ginseng (GPS-1 and GPS-2) through water extraction, ion-exchange chromatography and gel chromatography. The structural features and ability of the polysaccharides to inhibit lipid accumulation in oleic acid-induced HepG2 cells were studied. GPS-1 consisted of type I arabinogalactans (AG-I), arabinogalactans-II (AG-II) and rhamnogalacturonan I (RG-I) domains. GPS-2 was a pectin-like polysaccharide consisting mainly of the homogalacturonan (HG) domain and a small amount of AG domain. Both GPS-1 and GPS-2 had branches attaching on O-3 of (1 → 6)-GalA or O-4 of (1 → 2)-Rha and terminated by either Ara or Gal. An in vitro experiment revealed that GPS-1 treatment at 50-400 μg/ml could dose-dependently decrease intracellular lipid accumulation and cholesterol (TC) and triglycerides (TG) levels. GPS-1 exerted a more serious hypolipidemic effect than GPS-2 did. Moreover, GPS-1 considerably increased the phosphorylation of AMP-activated protein kinase (AMPK) and affected the expression of AMPK downstream targets, including the inhibition of the protein expression of sterol regulatory element-binding protein 1c (SREBP-1c) and activation of Acetyl-CoA carboxylase (ACC). Results suggest that GPS-1 could inhibit lipid accumulation via the AMPK the signalling pathway.

A fish oil-rich diet leads to lower adiposity and serum triglycerides but increases liver lipid peroxidation in fructose-fed rats

Background

Consumption of refined carbohydrates has risen in recent years alongside chronic diseases such as type 2 diabetes mellitus, dyslipidemia, obesity, and non-alcoholic fatty liver disease (NAFLD). Fructose is a monosaccharide made widely available in industrialized products, capable of inducing excessive weight gain and liver steatosis in animal models, while omega-3 fatty acids, present in foods such as fatty fish and fish oil, have shown to inhibit genes related to lipogenesis and decrease cardiovascular risk. Therefore, our objective was to evaluate the impact of a high-fructose diet on weight gain, biochemical and oxidative stress parameters, and liver histology and investigate fish oil’s potential protective role. Thirty male Wistar rats were divided into 3 groups: regular chow diet (CT), regular chow diet plus 20% fructose in drinking water (Fr), and a diet containing 10% fish oil plus 20% fructose in drinking water (FOFr). After 12 weeks, tissues of interest were collected for biochemical and histological analyses.

Results

Although fructose consumption did not lead to increased hepatic fat, it caused a significant increase in weight gain, white adipose tissue, and serum triglycerides in the Fr group, while fish oil promoted normalized serum triglycerides and even reduced adiposity in the FOFr group. Additionally, the inclusion of fish oil in the FOFr diet led to increased liver lipid peroxidation in the form of increased hepatic MDA.

Conclusions

It is concluded that fish oil can prevent important metabolic alterations caused by fructose consumption, but its dosage must be taken into account to prevent oxidative stress and potential liver damage.

Metformin May Contribute to Inter-individual Variability for Glycemic Responses to Exercise

Metformin and exercise independently improve glycemic control. Metformin traditionally is considered to reduce hepatic glucose production, while exercise training is thought to stimulate skeletal muscle glucose disposal. Collectively, combining treatments would lead to the anticipation for additive glucose regulatory effects. Herein, we discuss recent literature suggesting that metformin may inhibit, enhance or have no effect on exercise mediated benefits toward glucose regulation, with particular emphasis on insulin sensitivity. Importantly, we address issues surrounding the impact of metformin on exercise induced glycemic benefit across multiple insulin sensitive tissues (e.g., skeletal muscle, liver, adipose, vasculature, and the brain) in effort to illuminate potential sources of inter-individual glycemic variation. Therefore, the review identifies gaps in knowledge that require attention in order to optimize medical approaches that improve care of people with elevated blood glucose levels and are at risk of cardiovascular disease.

Noninvasive assessment of abdominal adipose tissues and quantification of hepatic and pancreatic fat fractions in type 2 diabetes mellitus

The purpose of this study was to evaluate adipose tissue distributions and hepatic and pancreatic fat contents using a 6-point Dixon MRI technique in type 2 diabetes mellitus (T2DM), and to assess associations between fat distributions and biochemical markers of insulin resistance. Intra-abdominal MRI was investigated in 14 T2DM patients, 13 age- and sex-matched healthy controls (HC) and 11 young HC using a 3 T Prisma MRI scanner. All T2DM subjects completed a fasting comprehensive metabolic panel, and demographic measurements were taken according to standardized methodologies. We observed excellent correlation (R² = 0.94) between hepatic fat fraction quantified using 6-point Dixon MRI and gold standard MRS, establishing the accuracy and reliability of the Dixon technique. Significantly increased visceral adipose tissue (VAT) volumes were found in T2DM patients compared to age-matched HC (1569.81 ± 670.62 cm³ vs. 1106.60 ± 566.85 cm³, p = .04). We also observed a trend of increasing subcutaneous adipose tissues (SAT), and total abdominal fat (TAT) volumes in T2DM compared to age-matched HC. Hepatic fat fraction percentage (HFF%) was 44.6% higher in T2DM compared to age-matched HC and 64.4% higher compared to young HC. Pancreatic fat fractions in the head and body/tail were higher in T2DM patients compared to both healthy cohorts. We also observed correlations between fat contents of the liver and pancreas in T2DM patients, and association between biochemical markers of T2DM with HFF, indicating a risk for non-alcoholic fatty liver disease among T2DM. In summary, this study provides evidence of T2DM patients having increased liver and pancreatic fat, as well as increased adipose tissues.

Ten-year remission rates in insulin-treated type 2 diabetes after biliopancreatic diversion with duodenal switch

BACKGROUND

Biliopancreatic diversion with duodenal switch (BPD-DS) confers the highest rate of type 2 diabetes (T2D) remission compared with other bariatric procedures. Previous studies suggest that type of antidiabetic therapy used before surgery and duration of disease influence postsurgical glycemic outcomes. Short-term, progressive improvement in insulin sensitivity and beta-cell function after metabolic surgery in patients with noninsulin-treated T2D has been demonstrated. Whether patients with more advanced disease can achieve sustained remission remains unclear.

OBJECTIVE

The aim of this study was to assess long-term glycemic outcomes in insulin-treated patients with T2D after BPD-DS and identify predictors of sustained diabetes remission or relapse.

SETTING

University-affiliated tertiary care center.

METHODS

Data from 141 patients with insulin-treated T2D who underwent BPD-DS between 1994 and 2006 with 10 years of follow-up data were collected from a prospective electronic database.

RESULTS

Follow-up was available in 132 patients (91%). At 10 years after metabolic surgery, 90 patients (68.1%) had a complete remission of diabetes, 3 (2.3%) had a partial remission, 21 (15.9%) had an improvement, and 3 (2.3%) were unchanged in their diabetes status. Fourteen patients died during the 10-year follow-up period. Relapse after an initial period of remission occurred in 15 (11.4%) patients. Insulin discontinuation was achieved in 97%. Duration of diabetes was an independent predictor of nonremission at 10 years.

CONCLUSIONS

The BPD-DS maintains remission at 10 years postoperatively in patients with more advanced diabetes. Long-term benefits of the BPD-DS on weight loss and glycemic control should be considered when offering metabolic surgery to patients with insulin-treated T2D.

Impaired nicotinamide adenine dinucleotide (NAD+ ) metabolism in diabetes and diabetic tissues: Implications for nicotinamide-related compound treatment

One of the biochemical abnormalities found in diabetic tissues is a decrease in the cytosolic oxidized to reduced forms of the nicotinamide adenine dinucleotide ratio (NAD⁺/NADH also known as pseudohypoxia) caused by oxidation of excessive substrates (glucose through the polyol pathway, free fatty acids and lactate). Subsequently, a decline in NAD⁺ levels as a result of the activation of poly adenine nucleotide diphosphate‐ribose polymerase (mainly in type 1 diabetes) or the inhibition of adenine nucleotide monophosphate‐activated protein kinase (in type 2 diabetes). Thus, replenishment of NAD⁺ levels by nicotinamide‐related compounds could be beneficial. However, these compounds also increase nicotinamide catabolites that cause oxidative stress. This is particularly troublesome for patients with diabetes, because they have impaired nicotinamide salvage pathway reactions at the level of nicotinamide phosphoribosyl transferase and phosphoribosyl pyrophosphate, which occurs by the following mechanisms. First, phosphoribosyl pyrophosphate synthesis from pentose phosphate pathway is compromised by a decrease in plasma thiamine and transketolase activity. Second, nicotinamide phosphoribosyl transferase expression is decreased because of reduced adenosine monophosphate‐activated protein kinase activity, which occurs in type 2 diabetes. The adenosine monophosphate‐activated protein kinase inhibition is caused by an activation of protein kinase C and D1 as a result of enhanced diacylglycerol synthesis caused by pseudohypoxia and increased fatty acids levels. In this regard, nicotinamide‐related compounds should be given with caution to treat diabetes. To minimize the risk and maximize the benefit, nicotinamide‐related compounds should be taken with insulin sensitizers (for type 2 diabetes), polyphenols, benfotiamine, acetyl‐L‐carnitine and aldose reductase inhibitors. The efficacy of these regimens can be monitored by measuring serum NAD⁺ and urinary nicotinamide catabolites.

The "discovery" of lipid droplets: A brief history of organelles hidden in plain sight

Mammalian lipid droplets (LDs), first described as early as the 1880s, were virtually ignored for more than 100 years. Between 1991 and the early 2000s, however, a series of discoveries and conceptual breakthroughs led to a resurgent interest in obesity as a disease, in the metabolism of intracellular triacylglycerol (TAG), and in the physical locations of LDs as cellular structures with their associated proteins. Insights included the recognition that obesity underlies major chronic diseases, that appetite is hormonally controlled, that hepatic steatosis is not a benign finding, and that diabetes might fundamentally be a disorder of lipid metabolism. In this brief review, I describe the metamorphosis of LDs from overlooked globs of stored fat to dynamic organelles that control insulin resistance, mitochondrial oxidation, and viral replication.

Mitochondrial Utilization of Competing Fuels Is Altered in Insulin Resistant Skeletal Muscle of Non-obese Rats (Goto-Kakizaki)

Aim

Insulin-resistant skeletal muscle is characterized by metabolic inflexibility with associated alterations in substrate selection, mediated by peroxisome-proliferator activated receptor δ (PPARδ). Although it is established that PPARδ contributes to the alteration of energy metabolism, it is not clear whether it plays a role in mitochondrial fuel competition. While nutrient overload may impair metabolic flexibility by fuel congestion within mitochondria, in absence of obesity defects at a mitochondrial level have not yet been excluded. We sought to determine whether reduced PPARδ content in insulin-resistant rat skeletal muscle of a non-obese rat model of T2DM (Goto-Kakizaki, GK) ameliorate the inhibitory effect of fatty acid (i.e., palmitoylcarnitine) on mitochondrial carbohydrate oxidization (i.e., pyruvate) in muscle fibers.

Methods

Bioenergetic function was characterized in oxidative soleus (S) and glycolytic white gastrocnemius (WG) muscles with measurement of respiration rates in permeabilized fibers in the presence of complex I, II, IV, and fatty acid substrates. Mitochondrial content was measured by citrate synthase (CS) and succinate dehydrogenase activity (SDH). Western blot was used to determine protein expression of PPARδ, PDK isoform 2 and 4.

Results

CS and SDH activity, key markers of mitochondrial content, were reduced by ∼10-30% in diabetic vs. control, and the effect was evident in both oxidative and glycolytic muscles. PPARδ (p < 0.01), PDK2 (p < 0.01), and PDK4 (p = 0.06) protein content was reduced in GK animals compared to Wistar rats (N = 6 per group). Ex vivo respiration rates in permeabilized muscle fibers determined in the presence of complex I, II, IV, and fatty acid substrates, suggested unaltered mitochondrial bioenergetic function in T2DM muscle. Respiration in the presence of pyruvate was higher compared to palmitoylcarnitine in both animal groups and fiber types. Moreover, respiration rates in the presence of both palmitoylcarnitine and pyruvate were reduced by 25 ± 6% (S), 37 ± 6% (WG) and 63 ± 6% (S), 57 ± 8% (WG) compared to pyruvate for both controls and GK, respectively. The inhibitory effect of palmitoylcarnitine on respiration was significantly greater in GK than controls (p < 10^-3).

Conclusion

With competing fuels, the presence of fatty acids diminishes mitochondria ability to utilize carbohydrate derived substrates in insulin-resistant muscle despite reduced PPARδ content.

RETRACTED: Lemon Balm Extract ALS-L1023 Regulates Obesity and Improves Insulin Sensitivity via Activation of Hepatic PPARα in High-Fat Diet-Fed Obese C57BL/6J Mice

Our previous studies demonstrated that peroxisome proliferator-activated receptor α (PPARα) activation reduces weight gain and improves insulin sensitivity in obese mice. Since excess lipid accumulation in non-adipose tissues is suggested to be responsible for the development of insulin resistance, this study was undertaken to examine whether the lemon balm extract ALS-L1023 regulates hepatic lipid accumulation, obesity, and insulin resistance and to determine whether its mechanism of action involves PPARα. Administration of ALS-L1023 to high-fat-diet-induced obese mice caused reductions in body weight gain, visceral fat mass, and visceral adipocyte size without changes of food consumption profiles. ALS-L1023 improved hyperglycemia, hyperinsulinemia, glucose and insulin tolerance, and normalized insulin-positive β-cell area in obese mice. ALS-L1023 decreased hepatic lipid accumulation and concomitantly increased the expression of PPARα target genes responsible for fatty acid β-oxidation in livers. In accordance with the in vivo data, ALS-L1023 reduced lipid accumulation and stimulated PPARα reporter gene expression in HepG2 cells. These effects of ALS-L1023 were comparable to those of the PPARα ligand fenofibrate, while the PPARα antagonist GW6471 inhibited the actions of ALS-L1023 on lipid accumulation and PPARα luciferase activity in HepG2 cells. Higher phosphorylated protein kinase B (pAkt)/Akt ratios and lower expression of gluconeogenesis genes were observed in the livers of ALS-L1023-treated mice. These results indicate that ALS-L1023 may inhibit obesity and improve insulin sensitivity in part through inhibition of hepatic lipid accumulation via hepatic PPARα activation.

[Ceramides, crucial actors in the development of insulin resistance and type 2 diabetes]

In healthy subjects, the balance between glucose production and its usage is precisely controlled. When circulating glucose reaches a critical threshold, pancreatic β-cells secrete insulin, which has two major actions: lowering circulating glucose concentrations by facilitating its uptake mainly in skeletal muscles and the liver, and inhibiting glucose production. Triglycerides are the main source of fatty acids to meet the energy needs of oxidative tissues and any excess is stored in adipocytes. Thus, adipose tissue acts as a trap for excess fatty acids released from plasma triglycerides. When the buffering action of adipose tissue to store fatty acids is impaired, they accumulate in other tissues where they are metabolized in several lipid species, including sphingolipid derivatives such as ceramides. Numerous studies have shown that ceramides are among the most active lipid second messengers to inhibit insulin signalling. This review describes the major role played by ceramides in the development of insulin resistance in peripheral tissues.

The correlation between CT features and insulin resistance levels in patients with T2DM complicated with primary pulmonary tuberculosis

The aim is to investigate the correlation between computed tomography (CT) features and insulin resistance levels in patients with type 2 diabetes mellitus (T2DM) complicated with primary pulmonary tuberculosis (PTB). Nearly, 268 untreated PTB patients complicated with T2DM were divided into two groups according to the optimal cutoff value of HOMA-IR score for the Chinese population: HOMA-IR ≤ 2.69 (Group I: 74 patients), >2.69 (Group II: 194 patients). The basic characteristics and changes of CT manifestations were analyzed. In the two groups, the detection rate of large segmented leafy shadow was 39.2% and 78.9%; the air bronchogram sign detection rate was 40.5% and 80.9%; the discovery rate of mouth-eaten cavity was 33.8% and 73.7%; the thin-walled cavity detection rate was 2.7% and 16.0%; the rate of multiple cavities was 35.1% and 69.6%; and bronchial tuberculosis was found in 4.1% and 35.6%, respectively. The detection rates of lesions in Group II were significantly higher than in Group I (p < .05). HOMA-IR was found independently associated with large segmented leafy shadow, air bronchial sign, thin-walled cavity, and bronchial tuberculosis. The level of insulin resistance can effectively reflect the severity of PTB patients with T2DM. CT scan can directly provide image information in clinics. These two examinations can guide clinicians to accurately formulate subsequent treatment plans.

Common genetic variation in obesity, lipid transfer genes and risk of Metabolic Syndrome: Results from IDEFICS/I.Family study and meta-analysis

As the prevalence of metabolic syndrome (MetS) in children and young adults is increasing, a better understanding of genetics that underlie MetS will provide critical insights into the origin of the disease. We examined associations of common genetic variants and repeated MetS score from early childhood to adolescence in a pan-European, prospective IDEFICS/I.Family cohort study with baseline survey and follow-up examinations after two and six years. We tested associations in 3067 children using a linear mixed model and confirmed the results with meta-analysis of identified SNPs. With a stringent Bonferroni adjustment for multiple comparisons we obtained significant associations(p < 1.4 × 10⁻⁴) for 5 SNPs, which were in high LD (r² > 0.85) in the 16q12.2 non-coding intronic chromosomal region of FTO gene with strongest association observed for rs8050136 (effect size(β) = 0.31, p_Wald = 1.52 × 10⁻⁵). We also observed a strong association of rs708272 in CETP with increased HDL (p = 5.63 × 10⁻⁴⁰) and decreased TRG (p = 9.60 × 10⁻⁵) levels. These findings along with meta-analysis advance etiologic understanding of childhood MetS, highlighting that genetic predisposition to MetS is largely driven by genes of obesity and lipid metabolism. Inclusion of the associated genetic variants in polygenic scores for MetS may prove to be fundamental for identifying children and subsequently adults of the high-risk group to allow earlier targeted interventions.

Obesity and Mechanisms of its Negative Impact on the Cardiovascular System

Currently, the number of obese people in the world is constantly increasing. Obesity has a direct negative impact on the heart and blood vessels, which can be considered not only as an appropriate response to an increase in the volume of circulating blood due to an increase in body weight, but also as a side tissue reaction of the myocardium to hormonal and metabolic changes inherent in obesity. Our review is devoted to the description of the mechanisms of influence of obesity on the structural and functional parameters of the heart, which create prerequisites for the development of cardiovascular diseases, as well as the existing contradictions. Currently, the accumulated data suggest that an excessive amount of adipose tissue, in addition to metabolic disorders, including insulin resistance, imbalance of adipokines and inflammation markers, leading to the development of lipotoxicity, can directly penetrate the myocardium and cause violations of its contractile properties, as well as affect the conduction of excitation pulses and provoke the development of rhythm and conduction disorders. The development of endothelial dysfunction in obesity ultimately leads to the development of atherosclerosis and coronary heart disease. In addition, obesity contributes to the emergence of risk factors for hypertension, diabetes, atrial fibrillation, chronic heart failure, obstructive sleep apnea syndrome. Given the differences in the literature on the effect of obesity on long-term outcomes in patients with cardiovascular diseases, it is important to conduct prospective studies on the role of individual factors and their combinations that affect the mortality of patients with cardiovascular diseases.

Beyond the CNS: The many peripheral roles of APOE

Apolipoprotein E (APOE) is a multifunctional protein synthesized and secreted by multiple mammalian tissues. Although hepatocytes contribute about 75% of the peripheral pool, APOE can also be expressed in adipose tissue, the kidney, and the adrenal glands, among other tissues. High levels of APOE production also occur in the brain, where it is primarily synthesized by glia, and peripheral and brain APOE pools are thought to be distinct. In humans, APOE is polymorphic, with three major alleles (ε2, ε3, and ε4). These allelic forms dramatically alter APOE structure and function. Historically, the vast majority of research on APOE has centered on the important role it plays in modulating risk for cardiovascular disease and Alzheimer's disease. However, the established effects of this pleiotropic protein extend well beyond these two critical health challenges, with demonstrated roles across a wide spectrum of biological conditions, including adipose tissue function and obesity, metabolic syndrome and diabetes, fertility and longevity, and immune function. While the spectrum of biological systems in which APOE plays a role seems implausibly wide at first glance, there are some potential unifying mechanisms that could tie these seemingly disparate disorders together. In the current review, we aim to concisely summarize a wide breadth of APOE-associated pathologies and to analyze the influence of APOE in the development of several distinct disorders in order to provide insight into potential shared mechanisms implied in these various pathophysiological processes.

Generation and characterization of dipeptidyl peptidase-IV inhibitory peptides from trypsin-hydrolyzed α-lactalbumin-rich whey proteins

Dipeptidyl peptidase-IV (DPP-IV) is an enzyme that break down the antidiabetic hormone glucagon-like peptide-1. Therefore, inhibition of DPP-IV could be an effective strategy to treat Type 2 diabetes (T2D). The α-lactalbumin-rich whey protein concentrate was hydrolyzed by trypsin, and the hydrolysates were then fractionated at a semi-preparative scale using a Superdex Gel filtration Chromatography. The peptides were analyzed by using HPLC coupled with tandem mass spectrometry (RP-HPLC-MS/MS), and their Dipeptidyl peptidase-IV inhibitory activity was determined by the enzymatic assay. Among tested fragments, a potent fragment (LDQWLCEKL), with the half-maximal inhibitory concentration (IC₅₀) of 131 μM was obtained. Further analysis shows that the LDQWLCEKL peptide corresponds to the amino acid sequence of f(115-123) in α-lactalbumin. Furthermore, LDQWLCEKL exhibited a typical non-competitive mode of inhibition. The results indicate that α-lactalbumin contains active peptides with DPP-IV inhibitory activity that may be used to prevent and treat T2D.

The Underlying Mechanisms of Curcumin Inhibition of Hyperglycemia and Hyperlipidemia in Rats Fed a High-Fat Diet Combined With STZ Treatment

Curcumin is the main secondary metabolite of Curcuma longa and other Curcuma spp, and has been reported to have some potential in preventing and treating some physiological disorders. This study investigated the effect of curcumin in inhibiting high-fat diet and streptozotocin (STZ)-induced hyperglycemia and hyperlipidemia in rats. Twenty-six male Sprague-Dawley (SD) rats (170–190 g) were randomly divided into a standard food pellet diet group (Control group), a high-fat diet and streptozotocin group (HF + STZ group), and a high-fat diet combined with curcumin and STZ group (HF + Cur + STZ group). Compared with the HF + STZ group, the HF + Cur + STZ group exhibited significantly reduced fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), alanine aminotransferase (AST), and aspartate transaminase (ALT) levels, as well as liver coefficients. In the livers of these rats, the expression of malondialdehyde (MDA) and Bax was downregulated, whereas that of superoxide dismutase (SOD) and Bcl-2 was upregulated. Moreover, the liver histology of these rats was improved and resembled that of the control rats. These results suggest that curcumin prevents high-fat diet and STZ-induced hyperglycemia and hyperlipidemia, mainly via anti-oxidant and anti-apoptotic mechanisms in the liver.

Sphingolipid Metabolism and Signaling in Skeletal Muscle: From Physiology to Physiopathology

Sphingolipids represent one of the major classes of eukaryotic lipids. They play an essential structural role, especially in cell membranes where they also possess signaling properties and are capable of modulating multiple cell functions, such as apoptosis, cell proliferation, differentiation, and inflammation. Many sphingolipid derivatives, such as ceramide, sphingosine-1-phosphate, and ganglioside, have been shown to play many crucial roles in muscle under physiological and pathological conditions. This review will summarize our knowledge of sphingolipids and their effects on muscle fate, highlighting the role of this class of lipids in modulating muscle cell differentiation, regeneration, aging, response to insulin, and contraction. We show that modulating sphingolipid metabolism may be a novel and interesting way for preventing and/or treating several muscle-related diseases.

Peroxiredoxin 6 Is a Key Antioxidant Enzyme in Modulating the Link between Glycemic and Lipogenic Metabolism

Insulin action and often glucose-stimulated insulin secretion are reduced in obesity. In addition, the excessive intake of lipids increases oxidative stress leading to overt type 2 diabetes mellitus (T2DM). Among the antioxidative defense systems, peroxiredoxin 6 (PRDX6) is able to reduce H2O2 and short chain and phospholipid hydroperoxides. Increasing evidences suggest that PRDX6 is involved in the pathogenesis of atherosclerosis and T2DM, but its role in the etiopathology of obesity and its complications is still not known. Therefore, in the present study, we sought to investigate this association by using PRDX6 knockout mice (PRDX6-/-). Metabolic parameters, like carbon dioxide (VCO2) production, oxygen consumption (VO2), and the respiratory exchange ratio (RER), were determined using metabolic cages. Intraperitoneal insulin and glucose tolerance tests were performed to evaluate insulin sensitivity and glucose tolerance, respectively. Liver and pancreas histochemical analyses were also evaluated. The expression of enzymes involved in lipid and glucose metabolism was analyzed by real-time PCR. Following 24 weeks of high-fat-diet (HFD), PRDX6-/- mice showed weight gain and higher food and drink intake compared to controls. VO2 consumption and VCO2 production decreased in PRDX6-/- mice, while the RER was lower than 0.7 indicating a prevalent lipid metabolism. PRDX6-/- mice fed with HFD showed a further deterioration on insulin sensitivity and glucose-stimulated insulin secretion. Furthermore, in PRDX6-/- mice, insulin did not suppress adipose tissue lipolysis with consequent hepatic lipid overload and higher serum levels of ALT, cholesterol, and triglycerides. Interestingly, in PRDX6-/- mice, liver and adipose tissue were associated with proinflammatory gene upregulation. Finally, PRDX6-/- mice showed a higher rate of nonalcoholic steatohepatitis (NASH) compared to control. Our results suggest that PRDX6 may have a functional and protective role in the development of obesity-related metabolic disorders such as liver diseases and T2DM and may be considered a potential therapeutic target against these illnesses.

Bioinformatics analysis of hepatic gene expression profiles in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is characterized by hyperglycemia. The liver has a critical role in regulating glucose homeostasis. The present study aimed to analyze hepatic gene expression profiles and to identify the key genes and pathways involved in T2DM. Gene expression profiles of 10 patients with T2DM and 7 subjects with normal glucose tolerance were downloaded from the Gene Expression Omnibus database. Subsequently, differentially expressed genes (DEGs) were identified and functional enrichment analysis was performed. In addition, a protein-protein interaction network was built and hub genes were identified. In total, 1,320 DEGs were identified, including 698 up- and 622 downregulated genes, and these were mainly enriched in positive regulation of transcription from RNA polymerase II promoter, cell adhesion, inflammatory response, positive regulation of apoptotic process, signal transduction and the Tolllike receptor signaling pathway. A total of 8 hub genes (G-protein subunit gamma transducin 2, ubiquitinconjugating enzyme E2 D1, glutamate metabotropic receptor 1, G-protein signaling modulator 1, C-X-C motif chemokine ligand 9, neurotensin, purinergic receptor P2Y1 and ring finger protein 41) were screened from the network. The present study may contribute to the elucidation of the hepatic pathology of T2DM.

Hepatic Metabolomic and Transcriptomic Responses Induced by Cecal Infusion of Sodium Propionate in a Fistula Pig Model

Short-chain fatty acids (SCFAs) are the major products of the microbial fermentation of indigestible carbohydrates. SCFAs are known to improve the host metabolism, but their underlying mechanism of action remains elusive. In this study, 16 growing pigs were infused with saline or sodium propionate solution (25 mL, 2 mol/L) through a cecal fistula twice a day during a 28 day experimental period. The results showed that the cecal infusion of the SCFA propionate decreased serum and liver triglyceride levels and increased serum PYY secretion in growing pigs. Hepatic metabolomics identified 12 metabolites that were significantly altered by propionate. These included decreased levels of lipid metabolism-related stearic acid and glycerol-2-phosphate; increased levels of TCA cycle components including malic acid, fructose-6-phosphate, and succinic acid; and decreased levels of the amino acid metabolism products aspartic acid and serine. Hepatic transcriptomics demonstrated that propionate inhibited fatty acid synthesis and promoted the lipid metabolic process. Pathway enrichment analysis showed that propionate accelerated gluconeogenesis and decreased glycolysis. Taken together, these data support a role of the SCFA propionate on host lipid and glucose metabolism.

Pancreatic Steatosis: An Emerging Clinical Entity

Pancreatic steatosis is an emerging clinical entity whose pathophysiology, natural history, and long-term complications are poorly characterized in the current literature. Epidemiological and prospective studies have described prevalence rates between 16% and 35%. Although the natural history is not well known, there are strong associations with obesity, metabolic syndrome, type 2 diabetes mellitus, and nonalcoholic fatty liver disease. Ectopic fat accumulation of the pancreas can cause chronic, low-grade inflammation from adipocytokine imbalances that involve beta cells and acinar cells. This mechanism can lead to pancreatic endocrine and exocrine dysfunction and initiate carcinogenesis. Although it is associated with morbid conditions, pancreatic steatosis may be amendable to treatment with a healthy diet, less meat consumption, exercise, and smoking cessation. Pancreatic steatosis should factor into clinical decision-making and prognostication of patients with pancreatic and systemic disease. This review seeks to describe the pathophysiology, natural history, diagnosis, and complications of this emerging clinically relevant entity.

Effect of electrical stimulation combined with diet therapy on insulin resistance via mTOR signaling

Insulin resistance (IR) is the impaired insulin response that causes decreased glucose tolerance. Electrical stimulation (ES) can improve insulin sensitivity in the skeletal muscle. However, the underlying molecular mechanisms remain to be elucidated. In the present study, the effect of ES and diet therapy on IR and the role of the mammalian target of rapamycin (mTOR) pathway in the improvement of IR by ES were investigated. A total of 70 Sprague-Dawley male rats were divided into five groups: Normal (n=10), IR control (n=15), diet (n=15), ES (n=15) and ES + diet (n=15) groups. An IR rat model was established by high-fat and high-carbohydrate diet for 5 weeks and confirmed by measurement of fasting plasma glucose (FPG), insulin, insulin sensitivity index (ISI) and IR index. ES on the Zusanli (ST36), Sanyinjiao (SP 6) and Weiwanxiashu (EX-B3) acupoints and the low-fat and low-carbohydrate diet demonstrated protective effects. The body weight, concentrations of FPG, insulin, triglycerides (TG), free fatty acids (FFA) and total cholesterol (TC) of the rats were detected. Pathologic changes in the liver and pancreatic tissues were assessed. Western blotting and immunohistochemistry were performed to determine the role of PI3K/Akt/mTOR signaling. Results demonstrated that ES and diet therapy significantly increased ISI and reduced FPG, IR index, FFA, TG, TC and weight. Inflammatory cell infiltration in the liver and pancreatic tissues was ameliorated and lipid droplets and cavitation in hepatocyte were decreased after ES and diet therapy. The administration of ES and diet therapy also enhanced glucose transport by the upregulation of glucose transporter 4 and accelerated glycogen synthesis through the suppression of glycogen synthase kinase 3α/β via PI3K/Akt/mTOR signaling. Hence, the present results demonstrated that ES combined with diet therapy improved IR through PI3K/Akt/mTOR signaling. The proposed therapy was superior to the method of diet alone.

The effect of Ferulago angulata (Schelchet) Boiss on blood glucose levels and suppression of diabetes in rats

Diabetes mellitus is a metabolic disease characterized by elevated blood glucose levels. Medicinal plant Ferulago angulata has anti-oxidant properties. The aim of the present research was to evaluate the effect of a hydroalcoholic extract of F. angulata on the blood glucose level and liver enzyme activity in diabetic male rats. Forty-eight male rats were randomly divided into eight groups, including normal and diabetic groups. Diabetes was induced by a single intraperitoneal injection of streptozotocin at 40 mg·kg-1 body weight. Rats were treated with an intraperitoneal injection of the extract for three weeks. At the end of the experimental period, fasting blood samples were collected, and blood glucose and liver enzyme activity were measured. This study demonstrated that serum glucose levels in diabetic groups treated with F. angulata were significantly lower than those in diabetic rats (P < 0.001). Alanine aminotransferase levels in diabetic rats treated with F. angulata were significantly decreased compared to diabetic rats (P < 0.001). Aspartate aminotransferase levels in diabetic rats treated with 200 and 400 mg·kg-1 F. angulata were significantly decreased compared to diabetic rats (P < 0.001). No significant differences were observed in the serum levels of blood glucose and liver enzymes in the normal group treated with different doses of the extract. These results show that the hydroalcoholic extract of F. angulata might be effective in the treatment of diabetes and consequently alleviate the liver damage caused by streptozotocin-induced diabetes mellitus. This effect might be due to the presence of flavonoids and their antioxidant features.

Role of Oleic Acid in the Gut-Liver Axis: From Diet to the Regulation of Its Synthesis via Stearoyl-CoA Desaturase 1 (SCD1)

The consumption of an olive oil rich diet has been associated with the diminished incidence of cardiovascular disease and cancer. Several studies have attributed these beneficial effects to oleic acid (C18 n-9), the predominant fatty acid principal component of olive oil. Oleic acid is not an essential fatty acid since it can be endogenously synthesized in humans. Stearoyl-CoA desaturase 1 (SCD1) is the enzyme responsible for oleic acid production and, more generally, for the synthesis of monounsaturated fatty acids (MUFA). The saturated to monounsaturated fatty acid ratio affects the regulation of cell growth and differentiation, and alteration in this ratio has been implicated in a variety of diseases, such as liver dysfunction and intestinal inflammation. In this review, we discuss our current understanding of the impact of gene-nutrient interactions in liver and gut diseases, by taking advantage of the role of SCD1 and its product oleic acid in the modulation of different hepatic and intestinal metabolic pathways.

Understanding the mechanisms of reversal of type 2 diabetes

Clinical and pathophysiological studies have shown type 2 diabetes to be a condition mainly caused by excess, yet reversible, fat accumulation in the liver and pancreas. Within the liver, excess fat worsens hepatic responsiveness to insulin, leading to increased glucose production. Within the pancreas, the β cell seems to enter a survival mode and fails to function because of the fat-induced metabolic stress. Removal of excess fat from these organs via substantial weight loss can normalise hepatic insulin responsiveness and, in the early years post-diagnosis, is associated with β-cell recovery of acute insulin secretion in many individuals, possibly by redifferentiation. Collectively, these changes can normalise blood glucose levels. Importantly, the primary care-based Diabetes Remission Clinical Trial (DiRECT) showed that 46% of people with type 2 diabetes could achieve remission at 12 months, and 36% at 24 months, mediated by weight loss. This major change in our understanding of the underlying mechanisms of disease permits a reassessment of advice for people with type 2 diabetes.

Pancreatic steatosis: an update

PURPOSE OF REVIEW

Pancreatic steatosis is a clinical entity with emerging significance and impacts patient health in a multitude of ways. It has a high prevalence in the global population with predilections for different demographics by age, sex and ethnicity. Understanding the pathophysiology, clinical features and complications of this entity may be important to understanding the consequences of the ongoing obesity global epidemic.

RECENT FINDINGS

Obesity and metabolic syndrome contribute to metabolic derangements that result in lipid mishandling by adipocytes. Adipocytokine imbalances in circulation and in the pancreatic microenvironment cause chronic, low-grade inflammation. The resulting beta cell and acinar cell apoptosis leads to pancreatic endocrine and exocrine dysfunction. Furthermore, these adipocytokines regulate cell growth, differentiation, as well as angiogenesis and lymphatic spread. These consequences of adipocyte infiltration are thought to initiate carcinogenesis, leading to pancreatic intraepithelial neoplasia and pancreatic ductal adenocarcinoma.

SUMMARY

Obesity will lead to millions of deaths each year and pancreatic steatosis may be the key intermediate entity that leads to obesity-related complications. Enhancing our understanding may reveal strategies for preventing mortality and morbidity related to the global epidemic of obesity. Further research is needed to determine the pathophysiology, long-term complications and effective treatment strategies for this condition.

Lipid droplet-membrane contact sites - from protein binding to function

In the general context of an increasing prevalence of obesity-associated diseases, which follows changing paradigms in food consumption and worldwide use of industry-transformed foodstuffs, much attention has been given to the consequences of excessive fattening on health. Highly related to this clinical problem, studies at the cellular and molecular level are focused on the fundamental mechanism of lipid handling in dedicated lipid droplet (LD) organelles. This Review briefly summarizes how views on LD functions have evolved from those of a specialized intracellular compartment dedicated to lipid storage to exerting a more generalized role in the stress response. We focus on the current understanding of how proteins bind to LDs and determine their function, and on the new paradigms that have emerged from the discoveries of the multiple contact sites formed by LDs. We argue that elucidating the important roles of LD tethering to other cellular organelles allows for a better understanding of LD diversity and dynamics.

TRB3 stimulates SIRT1 degradation and induces insulin resistance by lipotoxicity via COP1

Fatty acid-induced lipotoxicity plays an important role in the pathogenesis of diabetes mellitus. Our previous studies have documented that lipotoxicity contributes to the onset and development of diabetes via insulin resistance and/or compromised function of the pancreatic β-cells. However, the underlying molecular mechanisms associating lipotoxicity with insulin resistance remain to be fully elucidated. In this study, we explored the role of TRB3-COP1-SIRT1 in lipotoxicity leading to insulin resistance in hepatocytes. High fat diet (HFD)-fed mice and hepG2 cells stimulated with palmitate were utilized as models of lipid metabolism disorders. We analyzed the interactions of SIRT1 and COP1 with each other and with TRB3 using co-immunoprecipitation, western blotting. SIRT1 ubiquitination was also explored. Animal and cell experiments showed that lipotoxicity induced SIRT1 down-regulation at the protein level without altering the mRNA level, whereas, lipotoxicity led to up-regulation of TRB3 and COP1 at both the gene and protein levels. Mechanistic analysis indicated that COP1 functioned as an E3 Ub-ligase of SIRT1, responsible for its proteasomal degradation under lipotoxic conditions. TRB3 recruited COP1 to SIRT1 to promote its ubiquitination. Our data indicated for the first time that TRB3-COP1-SIRT1 pathway played an important role in lipotoxicity leading to insulin resistance in hepatocytes, and suggested that COP1 could be a potential therapeutic choice for the treatment of diabetes mellitus, with lipotoxicity being the important pathomechanism.

Fucoidan from Undaria pinnatifida has anti-diabetic effects by stimulation of glucose uptake and reduction of basal lipolysis in 3T3-L1 adipocytes

Fucoidan, a sulfated polysaccharide derived from brown seaweeds, has been shown to reduce blood glucose levels and improve insulin sensitivity in mice. We investigated the effects of fucoidan on lipid accumulation, lipolysis, and glucose uptake in 3T3-L1 cells to test the hypothesis that fucoidan exerts an anti-diabetic function by acting directly on adipocytes. The 3T3-L1 cells were treated with 10, 50, 100, and 200 μg/mL of fucoidan from Undaria pinnatifida. Oil Red O staining and AdipoRed assay were used to determine lipid accumulation during adipocyte differentiation. Fucoidan was shown to reduce lipid accumulation and glycerol-3-phosphate dehydrogenase (GPDH) activity in a dose-dependent manner (P < .01). The expression of peroxisome proliferator-activated receptor γ (PPARγ), a major transcription factor associated with adipocyte differentiation, was also suppressed upon treatment with fucoidan. Treatment with fucoidan stimulated glucose uptake in normal adipocytes and restored insulin-stimulated glucose uptake in obesity-induced insulin resistant adipocytes, which were made by incubating hypertrophied 3T3-L1 cells with the conditioned media of RAW 264.7 macrophages (RAW-CM) (P < .01). In the presence of RAW-CM, fucoidan enhanced epinephrine-stimulated lipolysis but reduced basal lipolysis, as determined by non-esterified fatty acid into the culture medium (P < .001). These results suggest that fucoidan may have anti-diabetic effects by improving insulin-stimulated glucose uptake and inhibiting basal lipolysis in adipocytes without inducing adipogenesis.

Prevalence of Metabolic Syndrome and Its Components in Bamboutos Division's Adults, West Region of Cameroon

The prevalence of metabolic syndrome (MetS) and its associated risks remain unappreciated in Bamboutos Division, west region of Cameroon. This study aimed to evaluate the prevalence of MetS, its individual components, and associated risk factors among Bamboutos Division's adults population using a Joint Interim Statement of the International Diabetes Federation (IDF) Task Force on Epidemiology and Prevention definitions parameters. A cross-sectional study was conducted from May 2016 to May 2018 in Mbouda ADLUCEM Hospital and Mbouda District Hospital, two reference hospitals in Bamboutos Division, west region of Cameroon. Interview, physical and clinical examinations, and lipid and fasting blood glucose measurements were conducted for 604 adults. The definition of MetS proposed by IDF was used. The prevalence of MetS was 32.45% with highly significant female predominance (46.11% for females and 14.01 % for males). In the entire participants, the most common abnormalities were low-HDL (82.78%) and hypertriglyceridemia (53.97%) [p<0.001]. Participants with obesity (OR: 16.34; 95% CI: 9.21-28.96), overweight (OR: 7.45; 95% CI: 4.17-13.30), and highest hs-CRP (hs-CRP >11 mg/l) had a higher risk of developing MetS. The most common MetS component was abdominal obesity (OR: 353.13; 95% CI: 136.16-915.81). MetS is prevalent among Bamboutos Division's adults in west region of Cameroon and abdominal obesity is the most common MetS component. This study highlights the need for evidence-based prevention, diagnosis, and management of MetS and its associated factors among Bamboutos Division's adults in Cameroon.

Prevalence of undiagnosed diabetes and pre-diabetes in chronic periodontitis patients assessed by an HbA1c chairside screening protocol

OBJECTIVES

The objective of the present study was to implement a chairside diabetes screening strategy for the identification of undiagnosed hyperglycaemia in periodontal patients.

MATERIALS AND METHODS

Measurement of HbA1c was performed in patients (n = 139) diagnosed with periodontal disease to determine possible unknown hyperglycaemia. Patients fulfilled the criteria for screening according to the questionnaire by the Centers for Disease Control and Prevention (CDC). The Cobas® b101 in vitro diagnostic system was used for the measurement of glycosylated haemoglobin (HbA1c) in capillary blood. Body mass index (BMI) and waist circumference were also measured to determine splanchnic obesity. Periodontal parameters were assessed with an automated probe and included probing depth, clinical attachment loss, bleeding on probing and presence/absence of plaque.

RESULTS

Most patients had moderate periodontitis. Almost 25% of the subjects tested were found to have unknown hyperglycaemia while 80.5% of them had splanchnic obesity. A significant association was found between HbA1c and BMI (Mann-Whitney test; p = 0.0021) as well as between HbA1c and waist circumference (Spearman rho test; p = 0.0007). No differences were observed regarding periodontal parameters between subjects exhibiting HbA1c ≥ 5.7% and those with HbA1c < 5.7% (Mann-Whitney test; p > 0.05) although those with HbA1c ≥ 5.7% displayed higher proportions of sites with clinical attachment loss > 5 mm (z test with Bonferroni corrections; p < 0.05).

CONCLUSIONS

Periodontal patients, especially those with a bigger than normal BMI and waist circumference, are a target group worth screening for diabetes.

CLINICAL RELEVANCE

The dental practitioner can contribute significantly to the worldwide effort of health care professionals in diabetes screening and referring for early diagnosis of the disease.

ER stress contributes to high-fat diet-induced decrease of thyroglobulin and hypothyroidism

Recent studies revealed the emerging role of excess uptake of lipids in the development of hypothyroidism. However, the underlying mechanism is largely unknown. We investigated the effect of high-fat diet (HFD) on thyroid function and the role of endoplasmic reticulum (ER) in HFD-induced hypothyroidism. Male Sprague-Dawley rats were fed with HFD or control diet for 18 wk. HFD rats showed an impaired thyroid function, with decreased thyroglobulin (Tg) level. We found the ER stress was triggered in HFD rat thyroid glands and palmitate-treated thyrocytes. Luminal swelling of ER in thyroid epithelial cells of HFD rats was also observed. The rate of Tg degradation increased in palmitate-treated thyrocytes. In addition, applying 4-phenyl butyric acid to alleviate ER stress in HFD rats improved the decrease of Tg and thyroid function. Withdrawal of the HFD improved thyroid function . In conclusion, we demonstrate that ER stress mediates the HFD-induced hypothyroidism, probably by impairing the production of Tg, and attenuation of ER stress improves thyroid function. Our study provides the understanding of how HFD induces hypothyroidism.