Obesity, metabolic syndrome, adipocytes and vascular function: A holistic viewpoint

Is obesity-induced ECM remodeling a prelude to the development of various diseases?

Due to the increasing incidence rate of obesity worldwide and the associated complications such as type 2 diabetes and cardiovascular diseases, research on the adipose tissue physiology and the role of the extracellular matrix (ECM) has gained tremendous attention. The ECM, one of the most crucial components in body tissues, undergoes remodeling and regeneration of its constituents to guarantee normal tissue function. There is a crosstalk between fat tissue and various body organs, including but not limited to the liver, heart, kidney, skeletal muscle, and so forth. These organs respond to fat tissue signals through changes in ECM, function, and their secretory products. Obesity can cause ECM remodeling, inflammation, fibrosis, insulin resistance, and disrupted metabolism in different organs. However, the mechanisms underlying the reciprocal communication between various organs during obesity are still not fully elucidated. Gaining a profound knowledge of ECM alterations during the progression of obesity will pave the way toward developing potential strategies to either circumvent pathological conditions or open an avenue to treat complications associated with obesity.

Insulin resistance and heart failure with preserved ejection fraction. Pathogenetic and therapeutic crossroads

Insulin resistance, which is a fundamental pathogenetic factor of prediabetes, is closely associated with abdominal obesity on the one hand and the development of cardiovascular diseases, heart failure (HF), on the other. The pathogenetic role of insulin resistance is multifaceted and consists in the acceleration of atherosclerosis, the formation of left ventricular myocardial hypertrophy, including through mechanisms that do not depend on blood pressure, as well as the development of its diastolic dysfunction. The latter is the starting point for starting HF with preserved ejection fraction (HFpEF).

Compared with patients with HF with reduced ejection fraction, the presence of HFpEF determines a higher frequency of hospitalizations not due to decompensation of heart failure, but due to concomitant diseases, such as destabilization of the course of arterial hypertension, decompensation of type 2 diabetes mellitus, curation of which, in general, has a greater impact in terms of improving prognosis. Thus, in patients with prediabetes and HFpEF, the correction of insulin resistance as the underlying cause and trigger of cardiometabolic disorders can potentially improve not only insulin-glucose homeostasis, but also the parameters of myocardial diastolic function. This literature review is devoted to the accumulated experience of using metformin as a «strategic» antidiabetic drug in HFpEF and considering potential new points of its application as a protector of the cardiovascular system.

Interscapular fat is associated with impaired glucose tolerance and insulin resistance independent of visceral fat mass

OBJECTIVE

Dysregulated body fat distribution is a major determinant of various diseases. In particular, increased visceral fat mass and ectopic lipids in the liver are linked to metabolic disorders such as insulin resistance and type 2 diabetes. Furthermore, interscapular fat is considered to be a metabolically active fat compartment.

METHODS

This study measured interscapular fat mass and investigated its relationship with glucose metabolism in 822 individuals with a wide range of BMI values and different glucose tolerance statuses. Magnetic resonance imaging was used to quantify body fat depots, and an oral glucose tolerance test was performed to determine glucose metabolism.

RESULTS

Elevated interscapular fat mass was positively associated with age, BMI, and total body, visceral, and subcutaneous adipose tissue mass. High interscapular fat mass associated with elevated fasting glucose levels, glucose levels at 2 hours during the oral glucose tolerance test, glycated hemoglobin, and insulin resistance, independent of sex, age, and total body and visceral fat mass.

CONCLUSIONS

In conclusion, interscapular fat might be a highly specific fat compartment with a potential impact on glucose metabolism and the pathogenesis of diabetes mellitus.

Perivascular Adipose Tissue Inflammation: The Anti-Inflammatory Role of Ghrelin in Atherosclerosis Progression

Perivascular adipose tissue (PVAT) and its adipokines engage in bidirectional crosstalk with the vascular wall. Atherosclerosis disrupts this interaction through inflammation, rupture-prone plaques, and subsequent thrombosis. The cardioprotective effects of ghrelin are in contradiction to its adipogenic properties. The concurrent research of anti-/pro-atherogenic mechanisms of ghrelin and PVAT-derived adipokines provides a better understanding of atherosclerosis progression in metabolic disorders. In-depth coverage of the characteristic features of PVAT concerning vascular dysfunction, with a survey of ghrelin-induced anti-inflammatory effects on adipose tissue macrophage infiltration and the inhibitory activity of ghrelin on the proinflammatory adipokine secretion, show that the impact of ghrelin on the endothelial function should be studied in relation to PVAT.

Are dentists more prone to metabolic syndrome and occupational stress?

OBJECTIVE

The aim of this study was to investigate the prevalence of metabolic syndrome (MS) among dentists in Riyadh, Saudi Arabia. The study also explored the causes of occupational stress among the participating dentists.

MATERIALS & METHODS

The participants included a conveniently selected sample of dentists (N = 126; Males = 65; Females = 61). The participants' anthropometric measurements/blood sample analysis were carried out and they completed a self-administered questionnaire. Data analysis included demographics, gender/age wise comparison using SPSS (p < 0.05). For the diagnosis of MS, updated criteria of the National Cholesterol Education Program was applied.

RESULTS

Participants diagnosed with MS were 13 (10.3%), Males = 11(8.7%) and Females = 2(1.5%). Physical activity of 6 (15.8%) with MS was only 0-2 hours/week. 9 (14.5%) participants with MS declared positive family history for MS. The average systolic (117.55±11.33) and diastolic blood pressure (71.9±9.34) of the participants was found to be normal with no gender wise statistical difference. No gender wise statistical differences (p > 0.05) were observed for cholesterol, triglycerides and HDL. However, significant difference (p = 0.00) was found for the fasting glucose level (Males = 5.69±1.49; Females = 4.94±0.42). Overall mean scoring (3.00±1.11) for the stress showed that the participants fall into the average/moderate level of stress category (Males = 3.16±1.02; Females = 2.83±1.08). Almost two third (68.26%) of the participant's responded that they were under some kind of stress.

CONCLUSIONS

MS was found to be less frequent among the dentists working in the city of Riyadh. Overall, the dentists were under moderate level of occupational stress, with male dentists being more prone to work related stress.

Lotus seeds (Nelumbinis semen) as an emerging therapeutic seed: A comprehensive review

Nelumbinis semen is commonly known as lotus seeds that have been used as a vegetable, functional food, and medicine for 7,000 years. These are low caloric, a rich source of multiple nutrients and bioactive constituents, which make it a unique therapeutic food. N. semen plays an important part in the physiological functions of the body. Nowadays, people are more conscious about their health and desire to treat disease naturally with minimal side effects. So, functional foods are getting popularity due to a wide range of essential constituents, which are associated to decrease the risk of chronic diseases. These bioactive compounds from seeds are involved in anti-adipogenic, antioxidant, antitumor, cardiovascular, hepato-protective, anti-inflammatory, anti-fertility, anti-microbial, anti-viral, hypoglycemic, etc. Moreover, the relationship between functional compounds along with their mechanism of action in the body, their extraction from the seeds for further research would be of great interest.

Therapeutic mesenchymal stromal stem cells: Isolation, characterization and role in equine regenerative medicine and metabolic disorders

Mesenchymal stromal cells (MSC) have become a popular treatment modality in equine orthopaedics. Regenerative therapies are especially interesting for pathologies like complicated tendinopathies of the distal limb, osteoarthritis, osteochondritis dissecans (OCD) and more recently metabolic disorders. Main sources for MSC harvesting in the horse are bone marrow, adipose tissue and umbilical cord blood. While the acquisition of umbilical cord blood is fairly easy and non-invasive, extraction of bone marrow and adipose tissue requires more invasive techniques. Characterization of the stem cells as a result of any isolation method, is also a crucial step for the confirmation of the cells' stemness properties; thus, three main characteristics must be fulfilled by these cells, namely: adherence, expression of a series of well-defined differentiation clusters as well as pluripotency. EVs, resulting from the paracrine action of MSCs, also play a key role in the therapeutic mechanisms mediated by stem cells; MSC-EVs are thus largely implicated in the regulation of proliferation, maturation, polarization and migration of various target cells. Evidence that EVs alone represent a complex network 0involving different soluble factors and could then reflect biophysical characteristics of parent cells has fuelled the importance of developing highly specific techniques for their isolation and analysis. All these aspects related to the functional and technical understanding of MSCs will be discussed and summarized in this review.

Leptin in Atherosclerosis: Focus on Macrophages, Endothelial and Smooth Muscle Cells

Increasing adipose tissue mass in obesity directly correlates with elevated circulating leptin levels. Leptin is an adipokine known to play a role in numerous biological processes including regulation of energy homeostasis, inflammation, vascular function and angiogenesis. While physiological concentrations of leptin may exhibit multiple beneficial effects, chronically elevated pathophysiological levels or hyperleptinemia, characteristic of obesity and diabetes, is a major risk factor for development of atherosclerosis. Hyperleptinemia results in a state of selective leptin resistance such that while beneficial metabolic effects of leptin are dampened, deleterious vascular effects of leptin are conserved attributing to vascular dysfunction. Leptin exerts potent proatherogenic effects on multiple vascular cell types including macrophages, endothelial cells and smooth muscle cells; these effects are mediated via an interaction of leptin with the long form of leptin receptor, abundantly expressed in atherosclerotic plaques. This review provides a summary of recent in vivo and in vitro studies that highlight a role of leptin in the pathogenesis of atherosclerotic complications associated with obesity and diabetes.

Vascular endothelial growth factor-mediated peritoneal neoangiogenesis in peritoneal dialysis

Peritoneal dialysis (PD) is an important renal replacement therapy for patients with end-stage renal diseases, which is limited by peritoneal neoangiogenesis leading to ultrafiltration failure (UFF). Vascular endothelial growth factor (VEGF) and its receptors are key angiogenic factors involved in almost every step of peritoneal neoangiogenesis. Impaired mesothelial cells are the major sources of VEGF in the peritoneum. The expression of VEGF will be up-regulated in specific pathological conditions in PD patients, such as with non-biocompatible peritoneal dialysate, uremia and inflammation, and so on. Other working cells (i.e. vascular endothelial cells, macrophages and adipocytes) can also stimulate the secretion of VEGF. Meanwhile, hypoxia and activation of complement system further aggravate peritoneal injury and contribute to neoangiogenesis. There are several signalling pathways participating in VEGF-mediated peritoneal neoangiogenesis including tumour growth factor-β, Wnt/β-catenin, Notch and interleukin-6/signal transducer and activator of transcription 3. Moreover, VEGF is highly expressed in dialysate effluent of long-term PD patients and is associated with peritoneal transport function, which supports its role in the alteration of peritoneal structure and function. In this review, we systematically summarize the angiogenic effect of VEGF and evaluate it as a potential target for the prevention of peritoneal neoangiogenesis and UFF. Preservation of the peritoneal membrane using targeted therapy of VEGF-mediated peritoneal neoangiogenesis may increase the longevity of the PD modality for those who require life-long dialysis.

Doxepin Exacerbates Renal Damage, Glucose Intolerance, Nonalcoholic Fatty Liver Disease, and Urinary Chromium Loss in Obese Mice

Doxepin is commonly prescribed for depression and anxiety treatment. Doxepin-related disruptions to metabolism and renal/hepatic adverse effects remain unclear; thus, the underlying mechanism of action warrants further research. Here, we investigated how doxepin affects lipid change, glucose homeostasis, chromium (Cr) distribution, renal impairment, liver damage, and fatty liver scores in C57BL6/J mice subjected to a high-fat diet and 5 mg/kg/day doxepin treatment for eight weeks. We noted that the treated mice had higher body, kidney, liver, retroperitoneal, and epididymal white adipose tissue weights; serum and liver triglyceride, alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, and creatinine levels; daily food efficiency; and liver lipid regulation marker expression. They also demonstrated exacerbated insulin resistance and glucose intolerance with lower Akt phosphorylation, GLUT4 expression, and renal damage as well as higher reactive oxygen species and interleukin 1 and lower catalase, superoxide dismutase, and glutathione peroxidase levels. The treated mice had a net-negative Cr balance due to increased urinary excretion, leading to Cr mobilization, delaying hyperglycemia recovery. Furthermore, they had considerably increased fatty liver scores, paralleling increases in adiponectin, FASN, PNPLA3, FABP4 mRNA, and SREBP1 mRNA levels. In conclusion, doxepin administration potentially worsens renal injury, nonalcoholic fatty liver disease, and diabetes.

The influence of sex and body mass index on the association between soluble neprilysin and risk of heart failure hospitalizations

A higher neprilysin activity has been suggested in women. In this retrospective analysis, we evaluated the association of sex and body mass index (BMI) with soluble neprilysin (sNEP) and recurrent admissions among 1021 consecutive HF outpatients. The primary and secondary endpoints were the number of HF hospitalizations and all-cause mortality, respectively. The association between sNEP with either endpoint was evaluated across sex and BMI categories (≥ 25 kg/m² vs. < 25 kg/m²). Bivariate count regression (Poisson) was used, and risk estimates were expressed as incidence rates ratio (IRR). During a median follow-up of 6.65 years (percentile 25%-percentile 75%:2.83–10.25), 702 (68.76%) patients died, and 406 (40%) had at least 1 HF hospitalization. Median values of sNEP and BMI were 0.64 ng/mL (0.39–1.22), and 26.9 kg/m² (24.3–30.4), respectively. Left ventricle ejection fraction was < 40% in 78.9% of patients, and 28% were women. In multivariable analysis, sNEP (main effect) was positively associated with HF hospitalizations (p = 0.001) but not with mortality (p = 0.241). The predictive value of sNEP for HF hospitalizations varied non-linearly across sex and BMI categories (p-value for interaction = 0.003), with significant and positive effect only on women with BMI ≥ 25 kg/m² (p = 0.039). For instance, compared to men, women with sNEP of 1.22 ng/mL (percentile 75%) showed a significantly increased risk (IRRs: 1.26; 95% CI: 1.05–1.53). The interaction analysis for mortality did not support a differential prognostic effect for sNEP (p = 0.072). In conclusion, higher sNEP levels in overweight women better predicted an increased risk of HF hospitalization.

The Age-Dependent Increase of Metabolic Syndrome Requires More Extensive and Aggressive Non-Pharmacological and Pharmacological Interventions: A Cross-Sectional Study in an Italian Cohort of Obese Women

BACKGROUND

Metabolic syndrome is a combination of cardiovascular risk factors (i.e., visceral obesity, dyslipidaemia, glucose intolerance, and hypertension), which entails critical issues in terms of medical management and public health.

METHODS

The aim of the present cross-sectional study was to investigate the age-related changes of the single IDF (International Diabetes Federation) diagnostic criteria for metabolic syndrome (waist circumference, WC; high-density lipoprotein cholesterol, HDL-C; triglycerides; glucose; systolic and diastolic blood pressure, SBP and DBP) in a large population of (Italian) obese women (n = 1.000; body mass index, BMI >30 kg/m²; age: 18-83 yrs), subdivided into two subgroups depending on the presence (n = 630) or absence (n = 370) of metabolic syndrome. Parallelly, the percentages of treatment with hypolipidaemic drugs, hypoglycaemics, and antihypertensives and, among the treated subjects, of control of the underlying condition in accordance with the cut-offs of IDF criteria for dyslipidaemia, hyperglycaemia, and hypertension were determined over six age ranges (i.e., 18-30, 31-40, 41-50, 51-60, 61-70, and > 70 yrs).

RESULTS

The prevalence of metabolic syndrome increased with advancing age. In the subgroup with metabolic syndrome, an age-dependent increase in HDL-C, glycaemia, and SBP occurred, while the visceral adiposity was stable. In the same subgroup, triglycerides and DBP decreased age-dependently. In the subgroup without metabolic syndrome, an age-dependent increase in WC, HDL-C, glycaemia, SBP, and DBP was observed. A progressive age-dependent increase in the percentage of patients pharmacologically treated for the cardiometabolic abnormalities was detected in patients with metabolic syndrome, a similar trend being also observed in patients without metabolic syndrome only for the antihypertensives. A clear-cut disproportion between treated versus adequately controlled women (with pharmacotherapy) was detected in the whole population.

CONCLUSIONS

At least in an Italian context of obese females, the age-dependent worsening of glycaemia and BP exerts a fundamental pathophysiological role in the progressive increase of metabolic syndrome with advancing age, which appears to be not adequately treated in a large part of obese subjects. The results of the present study might be useful for public health decision-makers for programming future more extensive and aggressive non-pharmacological and pharmacological interventions in the obese population.

Relation between resistin, PPAR-γ, obesity and atherosclerosis in male albino rats

Obesity and atherosclerosis are inflammatory states involving variable metabolic signals. The adipokine resistin is implicated in adipose tissue dysfunction and is modulated by PPARγ. In this study, resistin and PPARγ role is investigated in the development of CVS disease. Forty-eight Adult male albino rats were divided into control, obesity and atherosclerotic groups; each group is divided into two subgroups; with and without PPARγ agonist administration for 8 weeks. To assess pathological changes; lipid profile, inflammatory mediator, serum resistin level and resistin expression in adipose tissue were measured. Aorta is histopathologically evaluated. It was found that resistin expression is significantly correlated with lipid profile and inflammatory status in obesity and atherosclerotic groups, and PPARγ agonist administration significantly improves inflammatory status and dyslipidemic profile across studied groups (p < .05). Aortic wall shows histopathological evidence of atherosclerosis in obesity group which is more evident in atherosclerotic group, and milder changes upon receiving PPARγ agonist.

Samnamul (Shoots of Aruncus dioicus) Inhibit Adipogenesis by Downregulating Adipocyte-Specific Transcription Factors in 3T3-L1 Adipocytes

Adipocyte-specific transcription factors and antioxidants are considered the best target of obesity. Aruncus dioicus var. kamtschaticus (A. dioicus, Samnamul) is easily available owing to edible and inexpensive. However, the anti-adipogenic effects of the underlying mechanism of A. dioicus extract (ADE) have not yet been reported. In the present study, we evaluate anti-adipogenic pathway in 3T3-L1 adipocytes, antioxidant activities and quantified phenolics using high-performance liquid chromatography of ADE. The results revealed ADE had reduced adipocyte differentiation (0.72-fold vs. MDI (media of differentiation) control), triglyceride (TG; 0.50-fold vs. MDI control, p < 0.001), and total cholesterol contents (0.77-fold vs. MDI control) by regulating adipocyte-specific transcription factors (C/EBPα, PPARγ, and SREBP1) and their downstream mRNA (AdipoQ, Ap2, SREBP1-c, and FAS) levels. Furthermore, ADE has higher total phenol and flavonoid contents and scavenging assay in the DPPH and ABTS+. In particularly, ADE contains chlorogenic acid (7.04 mg/kg), caffeic acid (20.14 mg/kg), ferulic acid (1.74 mg/kg), veratric acid (29.31 mg/kg), cinnamic acid (4.70 mg/kg), and quercetin (4.18 mg/kg). In conclusion, since these phenols, especially quercetin, in the ADE appear to reduce differentiation, TG and cholesterol content by regulating adipocyte-specific transcription factors in adipocytes, ADE has the potential to be developed into a new antioxidant and anti-obesity therapeutics.

Ecklonia Cava Extract Attenuates Endothelial Cell Dysfunction by Modulation of Inflammation and Brown Adipocyte Function in Perivascular Fat Tissue

It is well known that perivascular fat tissue (PVAT) dysfunction can induce endothelial cell (EC) dysfunction, an event which is related with various cardiovascular diseases. In this study, we evaluated whether Ecklonia cava extract (ECE) and pyrogallol-phloroglucinol-6,6-bieckol (PPB), one component of ECE, could attenuate EC dysfunction by modulating diet-induced PVAT dysfunction mediated by inflammation and ER stress. A high fat diet (HFD) led to an increase in the number and size of white adipocytes in PVAT; PPB and ECE attenuated those increases. Additionally, ECE and PPB attenuated: (i) an increase in the number of M1 macrophages and the expression level of monocyte chemoattractant protein-1 (MCP-1), both of which are related to increases in macrophage infiltration and induction of inflammation in PVAT, and (ii) the expression of pro-inflammatory cytokines (e.g., tumor necrosis factor-α (TNF-α) and interleukin (IL)-6, chemerin) in PVAT which led to vasoconstriction. Furthermore, ECE and PPB: (i) enhanced the expression of adiponectin and IL-10 which had anti-inflammatory and vasodilator effects, (ii) decreased HFD-induced endoplasmic reticulum (ER) stress and (iii) attenuated the ER stress mediated reduction in sirtuin type 1 (Sirt1) and peroxisome proliferator-activated receptor γ (PPARγ) expression. Protective effects against decreased Sirt1 and PPARγ expression led to the restoration of uncoupling protein -1 (UCP-1) expression and the browning process in PVAT. PPB or ECE attenuated endothelial dysfunction by enhancing the pAMPK-PI3K-peNOS pathway and reducing the expression of endothelin-1 (ET-1). In conclusion, PPB and ECE attenuated PVAT dysfunction and subsequent endothelial dysfunction by: (i) decreasing inflammation and ER stress, and (ii) modulating brown adipocyte function.

Efficiently Anti-Obesity Effects of Unsaturated Alginate Oligosaccharides (UAOS) in High-Fat Diet (HFD)-Fed Mice

Obesity and its related complications have become one of the leading problems affecting human health. However, current anti-obesity treatments are limited by high cost and numerous adverse effects. In this study, we investigated the use of a non-toxic green food additive, known as unsaturated alginate oligosaccharides (UAOS) from the enzymatic degradation of Laminaria japonicais, which showed effective anti-obesity effects in a high-fat diet (HFD) mouse model. Compared with acid hydrolyzed saturated alginate oligosaccharides (SAOS), UAOS significantly reduced body weight, serum lipid, including triacylglycerol (TG), total cholesterol (TC) and free fatty acids (FFA), liver weight, liver TG and TC, serum alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels, adipose mass, reactive oxygen species (ROS) formation, and accumulation induced in HFD mice. Moreover, the structural differences in β-d-mannuronate (M) and its C5 epimer α-l-guluronate (G) did not cause significant functional differences. Meanwhile, UAOS significantly increased both AMP-activated protein kinase α (AMPKα) and acetyl-CoA carboxylase (ACC) phosphorylation in adipocytes, which indicated that UAOS had an anti-obesity effect mainly through AMPK signaling. Our results indicate that UAOS has the potential for further development as an adjuvant treatment for many metabolic diseases such as fatty liver, hypertriglyceridemia, and possibly diabetes.

Protective Effects of Licochalcone A Ameliorates Obesity and Non-Alcoholic Fatty Liver Disease Via Promotion of the Sirt-1/AMPK Pathway in Mice Fed a High-Fat Diet

Licochalcone A is a chalcone isolated from Glycyrrhiza uralensis. It showed anti-tumor and anti-inflammatory properties in mice with acute lung injuries and regulated lipid metabolism through the activation of AMP-activated protein kinase (AMPK) in hepatocytes. However, the effects of licochalcone A on reducing weight gain and improving nonalcoholic fatty liver disease (NAFLD) are unclear. Thus, the present study investigated whether licochalcone A ameliorated weight loss and lipid metabolism in the liver of high-fat diet (HFD)-induced obese mice. Male C57BL/6 mice were fed an HFD to induce obesity and NAFLD, and then were injected intraperitoneally with licochalcone A. In another experiment, a fatty liver cell model was established by incubating HepG2 hepatocytes with oleic acid and treating the cells with licochalcone A to evaluate lipid metabolism. Our results demonstrated that HFD-induced obese mice treated with licochalcone A had decreased body weight as well as inguinal and epididymal adipose tissue weights compared with HFD-treated mice. Licochalcone A also ameliorated hepatocyte steatosis and decreased liver tissue weight and lipid droplet accumulation in liver tissue. We also found that licochalcone A significantly regulated serum triglycerides, low-density lipoprotein, and free fatty acids, and decreased the fasting blood glucose value. Furthermore, in vivo and in vitro, licochalcone A significantly decreased expression of the transcription factor of lipogenesis and fatty acid synthase. Licochalcone A activated the sirt-1/AMPK pathway to reduce fatty acid chain synthesis and increased lipolysis and β-oxidation in hepatocytes. Licochalcone A can potentially ameliorate obesity and NAFLD in mice via activation of the sirt1/AMPK pathway.

Leptin and the vasculature in young adults: The African-PREDICT study

BACKGROUND AND AIM

Information regarding the effect of leptin on the vasculature in young healthy adults at risk for cardiovascular disease development is limited. We therefore examined the associations between measures of subclinical atherosclerosis (carotid intima-media thickness, carotid cross-sectional wall area), large artery stiffness (pulse wave velocity) and a measure of endothelial dysfunction (von Willebrand factor [vWF]) with leptin in young healthy men and women.

METHODS

In a cross-sectional study in South Africa involving 820 normotensive individuals (337 men and 483 women) aged 20-30 years, we measured carotid intima-media thickness, carotid cross-sectional wall area, pulse wave velocity, vWF from citrated plasma and leptin from serum.

RESULTS

Despite sevenfold higher leptin in women than men (P < 0.001), only in young healthy men, we observed negative, independent associations between measures of carotid wall thickness (carotid intima-media thickness: R2  = 0.05; β = -0.20; P = 0.036; carotid cross-sectional wall area: R2  = 0.05; β = -0.20; P = 0.035) with leptin in multivariable-adjusted regression analyses. When reviewing these associations across body mass index categories, we found an association to be evident only in overweight men (carotid intima-media thickness: R2  = 0.15; β = -0.41; P = 0.007; carotid cross-sectional wall area: R2  = 0.21; β = -0.47; P = 0.002). No association was observed in the women or between pulse wave velocity and vWF with leptin.

CONCLUSION

In young healthy men, we found a beneficial inverse association between measures of carotid wall thickness and circulating leptin, thereby supporting a potential vascular protective role of leptin.

Frequency of metabolic syndrome and its associated factors in health care workers

BACKGROUND

In recent decades, metabolic syndrome is one of the most important public health risk factors. Having this in mind, the present study was conducted to evaluate the frequency of metabolic syndrome and its associated risk factors in healthcare workers.

METHOD

This study is a cross-sectional study conducted on 410 healthcare workers in a teaching hospital in Iran. Demographic, occupational, and psychosocial characteristics were assessed using questionnaire. Assessment of metabolic syndrome of hospital staff was performed at workplace during their medical examination.

RESULTS

The frequency of metabolic syndrome was found to be 22.4%. This relationship was found among blood pressure and occupational stress, despite the fact that there was no significant relationship between metabolic syndrome and occupational stress. Higher age, having shift work, and inactivity were associated with metabolic syndrome.

CONCLUSION

Considering the high frequency of metabolic syndrome among Iranian healthcare workers, it is advised that effective management should be employed to correct the occupational and psychosocial factors associated with this syndrome.

Perivascular adipose tissue (PVAT) in atherosclerosis: a double-edged sword

Perivascular adipose tissue (PVAT), the adipose tissue that surrounds most of the vasculature, has emerged as an active component of the blood vessel wall regulating vascular homeostasis and affecting the pathogenesis of atherosclerosis. Although PVAT characteristics resemble both brown and white adipose tissues, recent evidence suggests that PVAT develops from its own distinct precursors implying a closer link between PVAT and vascular system. Under physiological conditions, PVAT has potent anti-atherogenic properties mediated by its ability to secrete various biologically active factors that induce non-shivering thermogenesis and metabolize fatty acids. In contrast, under pathological conditions (mainly obesity), PVAT becomes dysfunctional, loses its thermogenic capacity and secretes pro-inflammatory adipokines that induce endothelial dysfunction and infiltration of inflammatory cells, promoting atherosclerosis development. Since PVAT plays crucial roles in regulating key steps of atherosclerosis development, it may constitute a novel therapeutic target for the prevention and treatment of atherosclerosis. Here, we review the current literature regarding the roles of PVAT in the pathogenesis of atherosclerosis.

Capsaicin in Metabolic Syndrome

Capsaicin, the major active constituent of chilli, is an agonist on transient receptor potential vanilloid channel 1 (TRPV1). TRPV1 is present on many metabolically active tissues, making it a potentially relevant target for metabolic interventions. Insulin resistance and obesity, being the major components of metabolic syndrome, increase the risk for the development of cardiovascular disease, type 2 diabetes, and non-alcoholic fatty liver disease. In vitro and pre-clinical studies have established the effectiveness of low-dose dietary capsaicin in attenuating metabolic disorders. These responses of capsaicin are mediated through activation of TRPV1, which can then modulate processes such as browning of adipocytes, and activation of metabolic modulators including AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor α (PPARα), uncoupling protein 1 (UCP1), and glucagon-like peptide 1 (GLP-1). Modulation of these pathways by capsaicin can increase fat oxidation, improve insulin sensitivity, decrease body fat, and improve heart and liver function. Identifying suitable ways of administering capsaicin at an effective dose would warrant its clinical use through the activation of TRPV1. This review highlights the mechanistic options to improve metabolic syndrome with capsaicin.

Diagnostic imaging in the management of patients with metabolic syndrome

Metabolic syndrome (MetS) is the constellation of metabolic risk factors that might foster development of type 2 diabetes and cardiovascular disease. Abdominal obesity and insulin resistance play a prominent role among all metabolic traits of MetS. Because intervention including weight loss can reduce these morbidity and mortality in MetS, early detection of the severity and complications of MetS could be useful. Recent advances in imaging modalities have provided significant insight into the development and progression of abdominal obesity and insulin resistance, as well as target organ injuries. The purpose of this review is to summarize advances in diagnostic imaging modalities in MetS that can be applied for evaluating each components and target organs. This may help in early detection, monitoring target organ injury, and in turn developing novel therapeutic target to alleviate and avert them.

A systematic review and meta-analysis: Effectiveness of internet empowerment-based self-management interventions on adults with metabolic diseases

AIM

To synthesize the effects of Internet empowerment-based self-management interventions on adults with metabolic diseases.

BACKGROUND

Metabolic diseases are prevalent and burden healthcare systems; they have become a major health problem worldwide. The effects of IESMIs on lifestyle changes have been shown to improve adults' physiological and psychological conditions. However, we found no systematic review evaluating these effects.

DESIGN

Systematic review and meta-analysis of randomized and non-randomized controlled trials, conducted according to the Cochrane handbook.

DATA RESOURCES

A literature search was conducted using the Airiti Library, Association for Computing Machinery, CINAHL, Cochrane Library, Embase, ProQuest, PubMed/MEDLINE and Index of the Taiwan Periodical Literature System databases (earliest-June 2016).

REVIEW METHODS

Two reviewers used the Cochrane Collaboration bias assessment tool to assess the methodological quality of included studies. Extracted data were entered and analysed using RevMan 5.3.5 software. Inverse variance was used to estimate effect sizes. Weighted and standardized mean differences with 95% confidence intervals were calculated using a random effects model. Subgroup and sensitivity analyses were performed.

RESULTS

Twenty-one randomized controlled trials were reviewed. Meta-analysis showed that the intervention significantly improved adults' exercise habits, glycated haemoglobin (HbA1c) levels, body weight, empowerment levels and quality of life.

CONCLUSION

The intervention significantly improve the health status of adults with metabolic diseases, in particular their exercise habits, HbA1c levels, body weight, empowerment and quality of life. The intervention provides more convenient and faster access to healthcare for busy individuals with time constraints. These results suggest that healthcare professionals could develop accessible and friendly interactive online interfaces for patients to expand the use of these interventions in the clinical setting.

C1q/TNF-related protein 9 improves the anti-contractile effects of perivascular adipose tissue via the AMPK-eNOS pathway in diet-induced obese mice

The anti-contractile property of perivascular adipose tissue (PVAT) is abolished through an endothelium-dependent pathway in obesity. C1q/tumor necrosis factor-related protein (CTRP)9 improved endothelial function by promoting endothelium-dependent vasodilatation. The aims of this study were to investigate whether CTRP9 improves the anti-contractile effect of PVAT and protects against PVAT dysfunction in obese mice. The mice were treated with a high-fat diet with or without CTRP9 treatment. Thoracic aortas with or without PVAT (PVAT+ or PVAT-) were prepared, and concentration-dependent responses to phenylephrine were measured. Obese mice showed a significantly increased contractile response, which was suppressed by CTRP9 treatment both with and without PVAT. PVAT significantly reduced the anti-contractile effect in obese mice, which was partially restored by CTRP9 treatment. Treatment of the aortic rings (PVAT+) with inhibitors of AMP protein kinase (AMPK), Akt and endothelial nitric oxide synthase (eNOS) attenuated the beneficial effect of CTRP9 on PVAT. Similar results were observed when we pretreated the aortic rings with CTRP9 ex vivo. CTRP9 significantly enhanced the phosphorylation levels of AMPK, Akt and eNOS, and reduced superoxide production and TNF-α levels in PVAT from obese mice. Our study suggests that CTRP9 enhanced the anti-contractile effect of PVAT and improved PVAT function by activating the AMPK-eNOS pathway in obese mice.

Comparisons between perivascular adipose tissue and the endothelium in their modulation of vascular tone

The endothelium is an established modulator of vascular tone; however, the recent discovery of the anti-contractile nature of perivascular adipose tissue (PVAT) suggests that the fat, which surrounds many blood vessels, can also modulate vascular tone. Both the endothelium and PVAT secrete vasoactive substances, which regulate vascular function. Many of these factors are common to both the endothelium and PVAT; therefore, this review will highlight the potential shared mechanisms in the modulation of vascular tone. Endothelial dysfunction is a hallmark of many vascular diseases, including hypertension and obesity. Moreover, PVAT dysfunction is now being reported in several cardio-metabolic disorders. Thus, this review will also discuss the mechanistic insights into endothelial and PVAT dysfunction in order to evaluate whether PVAT modulation of vascular contractility is similar to that of the endothelium in health and disease.

LINKED ARTICLES

This article is part of a themed section on Molecular Mechanisms Regulating Perivascular Adipose Tissue - Potential Pharmacological Targets? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.20/issuetoc.

[Metabolic syndrome in public service drivers in Armenia, Colombia]

OBJECTIVE

To characterize and compare the population of public service drivers of a transport company in Armenia, Colombia.

MATERIALS AND METHODS

Taxi and bus drivers from a transport company of Armenia, Colombia participated in an Analytical cross-sectional study. The analysis of the variables was made through Statgraphics Centurion XVI. The comparison of variables as well as multiple and logistic regression were carried out.

RESULTS

125 individuals participated, 8 were removed, and finally there were 117 male drivers as aim of research. The 28.21 % of individuals have driven small buses and the 71.79 % have driven cars. The increase in alcohol consumption was remarkable compared to tobacco. The 60.69 % of subjects did not get exercise. Besides, the BMI average and abdominal circumference was 28.03 kg/m2 and 100.09 cm respectively. The triglyceride average and serum HDL-C were 207.53 mg/dL to 33.12 mg/dL. 49.57 % of all drivers, fulfilled the Metabolic Syndrome diagnostic criteria. Statistically significant differences were found in the values of BMI, waist circumference, systolic blood pressure, diastolic blood pressure, weekly exercise, triglycerides and fasting glucose between individuals with and without Metabolic Syndrome.

CONCLUSION

Public service drivers have a profile risk for developing Metabolic Syndrome. Obesity, hypertriglyceridemia and low HDL-C were the main alarm parameters of the presence of Metabolic Syndrome.

Almond Skin Polyphenol Extract Inhibits Inflammation and Promotes Lipolysis in Differentiated 3T3-L1 Adipocytes

Studies have shown that polyphenols reduce the risk of inflammation-related diseases and upregulates energy expenditure in adipose tissue. Here, we investigated the mechanism of the anti-inflammatory and antiobesity effects of almond skin polyphenol extract (ASP) in differentiated 3T3-L1 adipocytes. The antioxidant effects of ASP were measured based on DPPH radical scavenging activity, Trolox equivalent antioxidant capacity, and total phenolic content. Differentiated 3T3-L1 cells were treated with ASP. Subsequently, lipolysis proteins and transcription factors of adipogenesis were measured. The proinflammatory mediators monocyte chemotactic protein-1 (MCP-1) and chemokine ligand 5 (CCL-5) were determined by enzyme-linked immunosorbent assay. We found that ASP significantly promoted phosphorylation of AMP-activated protein kinase (AMPK), increased activity of adipose triglyceride lipase and hormone-sensitive lipase, and inhibited adipogenesis-related transcription factors. In addition, ASP inhibited the tumor necrosis factor-α (TNF-α)-induced cell inflammatory response via downregulation of MCP-1 and CCL-5 secretion. This study suggests that ASP regulates lipolysis through activation of AMPK, reduced adipogenesis, and suppresses proinflammatory cytokines in adipocytes.

Angiogenesis and Inflammation in Peritoneal Dialysis: The Role of Adipocytes

Chronic inflammation and angiogenesis are the most common complications in patients undergoing maintenance peritoneal dialysis (PD), resulting in progressive peritoneum remolding and, eventually, utrafiltration failure. Contributing to the deeper tissue under the peritoneal membrane, adipocytes play a neglected role in this process. Some adipokines act as inflammatory and angiogenic promoters, while others have the opposite effects. Adipokines, together with inflammatory factors and other cytokines, modulate inflammation and neovascularization in a coordinated fashion. This review will also emphasize cellular regulators and their crosstalk in long-term PD. Understanding the molecular mechanism, targeting changes in adipocytes and regulating adipokine secretion will help extend therapeutic methods for preventing inflammation and angiogenesis in PD.

Molecular Mechanisms of Latent Inflammation in Metabolic Syndrome. Possible Role of Sirtuins and Peroxisome Proliferator-Activated Receptor Type γ

The problem of metabolic syndrome is one of the most important in medicine today. The main hazard of metabolic syndrome is development of latent inflammation in adipose tissue, which promotes atherosclerosis, non-alcoholic fatty liver disease, myocarditis, and a number of other illnesses. Therefore, understanding of molecular mechanisms of latent inflammation in adipose tissue is very important for treatment of metabolic syndrome. Three main components that arise during hypertrophy and hyperplasia of adipocytes underlie such inflammation: endoplasmic reticulum stress, oxidative stress, and hypoxia. Each of these components mediates activation in different ways of the key factor of inflammation - NF-κB. For metabolic syndrome therapy, it is suggested to influence a number of inflammatory signaling components by activating other cell factors to suppress development of inflammation. Such potential factors are peroxisome proliferator-activated receptors type γ that suppress transcription factor NF-κB through direct contact or via kinase of a NF-κB inhibitor (IKK), and also the antiinflammatory transcription factor AP-1. Other possible targets are type 3 NAD+-dependent histone deacetylases (sirtuins). There are mutually antagonistic relationships between NF-κB and sirtuin type 1 that prevent development of inflammation in metabolic syndrome. Moreover, sirtuin type 1 inhibits the antiinflammatory transcription factor AP-1. Study of the influence of these factors on the relationship between macrophages and adipocytes, macrophages, and adipose tissue-derived stromal cells can help to understand mechanisms of signaling and development of latent inflammation in metabolic syndrome.

Loss of anti-contractile effect of perivascular adipose tissue in offspring of obese rats

Rationale:

Maternal obesity pre-programmes offspring to develop obesity and associated cardiovascular disease. Perivascular adipose tissue (PVAT) exerts an anti-contractile effect on the vasculature, which is reduced in hypertension and obesity.

Objective:

The objective of this study was to determine whether maternal obesity pre-programmes offspring to develop PVAT dysfunction in later life.

Methods:

Female Sprague–Dawley rats were fed a diet containing 10% (control) or 45% fat (high fat diet, HFD) for 12 weeks prior to mating and during pregnancy and lactation. Male offspring were killed at 12 or 24 weeks of age and tension in PVAT-intact or -denuded mesenteric artery segments was measured isometrically. Concentration–response curves were constructed to U46619 and norepinephrine.

Results:

Only 24-week-old HFD offspring were hypertensive (P<0.0001), although the anti-contractile effect of PVAT was lost in vessels from HFD offspring of each age. Inhibition of nitric oxide (NO) synthase with 100 μMl-NMMA attenuated the anti-contractile effect of PVAT and increased contractility of PVAT-denuded arteries (P<0.05, P<0.0001). The increase in contraction was smaller in PVAT-intact than PVAT-denuded vessels from 12-week-old HFD offspring, suggesting decreased PVAT-derived NO and release of a contractile factor (P<0.07). An additional, NO-independent effect of PVAT was evident only in norepinephrine-contracted vessels. Activation of AMP-activated kinase (with 10 μM A769662) was anti-contractile in PVAT-denuded (P<0.0001) and -intact (P<0.01) vessels and was due solely to NO in controls; the AMPK effect was similar in HFD offspring vessels (P<0.001 and P<0.01, respectively) but was partially NO-independent.

Conclusions:

The diminished anti-contractile effects of PVAT in offspring of HFD dams are primarily due to release of a PVAT-derived contractile factor and reduced NO bioavailability.

Metalloproteinases and leptin in vehicle drivers of public service with metabolic syndrome in Armenia, Quindío

OBJECTIVE

To describe the relationship between metalloproteinase (MMP) 2, MMP-9, and leptin in drivers of public service vehicles with metabolic syndrome in the city of Armenia (Quindio, Colombia).

METHODS

Leptin was measured using Millipore ELISA kits. MMP-2 and MMP-9 were measured with ELISA kits from R&D Systems.

RESULTS

Fifty-seven male drivers with metabolic syndrome with a mean age of 45.35years, BMI of 29.81, and an abdominal circumference of 105.75cm were identified. Blood pressure values were 126.5/82.5mmHg. Leptin, MMP-2, and MMP-9 levels were 24.6ng/mL, 28,1ng/mL, and 7.5ng/mL respectively. The relationship between leptin and waist circumference was statistically significant (P<.001). The explained variation (R(2)) in waist circumference, is explained in a 80.12% for the study variables, has a statistically significant association with BMI (P<.001), MMP-2 (P=.01), age (P=.01), SBP (P<.001) and DBP (P<.001). The R(2) of leptin, is explained in a 69.56% for the study variables, has a statistically significant association with BMI (P<.001), MMP-2 (P=.05) and triglycerides (P=.02). The R(2) of MMP-2, explained in 41.82% of the study variables and has a statistically significant association with waist circumference (P=.01), glucose (P=.01) and age (P=.03).

CONCLUSIONS

Statistically significant associations were found between waist circumference and MMP-2; leptin and MMP-2, and MMP-2 and waist circumference and blood glucose.

Snacking between main meals is associated with a higher risk of metabolic syndrome in a Mediterranean cohort: the SUN Project (Seguimiento Universidad de Navarra)

Objective

To evaluate the association of snacking between main meals with the risk of developing metabolic syndrome.

Design

A dynamic prospective cohort study (the SUN Project; Seguimiento Universidad de Navarra). Snack consumption was evaluated using the question: ‘Do you have the habit of snacking between main meals?’ Metabolic syndrome was defined according to the updated harmonizing criteria. We estimated multivariable-adjusted relative risks (RR) of metabolic syndrome and their 95 % confidence intervals using Poisson regression models. An exploratory factor analysis was also used to identify patterns of snacking.

Setting

University of Navarra, Spain.

Subjects

The study included 6851 university graduates, initially free of metabolic syndrome, and followed-up them for a median of 8·3 years.

Results

Among our participants, 34·6 % reported usual snacking between main meals. The cumulative incidence of metabolic syndrome was 5·1 % (9·5 % among men and 2·8 % among women). Snacking between main meals was significantly associated with higher risk for developing metabolic syndrome after multivariable adjustment (RR=1·44; 95 %CI 1·18, 1·77). Higher adherence to an ‘unhealthy snacking pattern’ was also independently associated with increased incidence of metabolic syndrome (fourth quartile of adherence compared with non-snacking: RR=1·68; 95 % CI 1·23, 2·29; P for trend <0·001).

Conclusions

Our findings suggest that avoidance of snacking between main meals can be included among the preventive approaches to reduce the risk of metabolic syndrome development, especially when snacks contain foods of poor nutritional quality.

Vaspin promotes 3T3-L1 preadipocyte differentiation

Vaspin, a novel adipocyte factor secreted from visceral adipose tissues, is associated with obesity and insulin resistance and can regulate glucose and lipid metabolism, increase insulin sensitivity, and suppress inflammation; however, the underlying mechanisms remain unknown. Proliferation and maladaptive differentiation are important pathological mechanisms underlying obesity. This study aimed to evaluate the effects of vaspin on the proliferation and differentiation of preadipocyte 3T3-L1 cells and to explore the likely mechanisms responsible for 3T3-L1 differentiation. Vaspin was added to cultured 3T3-L1 cells, and the differentiation of adipocytes was evaluated using Oil Red O staining. The AKT signaling pathway and specific differentiation factors related to the differentiation of preadipocyte 3T3-L1 cells, peroxisome proliferator-activated γ and the CCAAT/enhancer-binding protein (C/EBP) family, were evaluated using reverse transcription polymerase chain reaction (RT-PCR) and western blot analyses during the early phase of differentiation. Additionally, adiponectin mRNA, interleukin-6 mRNA (IL-6 mRNA), and glucose transporter-4 (GLUT4) protein levels were measured in the differentiated adipocytes. The results indicated that vaspin promotes the intracellular accumulation of lipids and increases differentiation-related factors, including peroxisome proliferator-activated receptor γ, C/EBPα, and free fatty acid-binding protein 4 (FABP4), in a dose-dependent manner. Additionally, vaspin (200 ng/mL) increased the mRNA and protein levels of C/EBPβ, peroxisome proliferator-activated γ, C/EBPα, and FABP4. Moreover, compared with the control, significantly smaller eight-day differentiated adipocytes were observed, and these cells exhibited decreased IL-6 mRNA and increased GLUT4 mRNA levels; these results also indicated the potential of vaspin to promote the insulin-mediated AKT signaling pathway during the early phase of differentiation. In conclusion, vaspin is able to promote the differentiation of 3T3-L1 preadipocytes and may increase their sensitivity to insulin and suppress obesity.

Perivascular fat, AMP-activated protein kinase and vascular diseases

Perivascular adipose tissue (PVAT) is an active endocrine and paracrine organ that modulates vascular function, with implications for the pathophysiology of cardiovascular disease (CVD). Adipocytes and stromal cells contained within PVAT produce mediators (adipokines, cytokines, reactive oxygen species and gaseous compounds) with a range of paracrine effects modulating vascular smooth muscle cell contraction, proliferation and migration. However, the modulatory effect of PVAT on the vascular system in diseases, such as obesity, hypertension and atherosclerosis, remains poorly characterized. AMP-activated protein kinase (AMPK) regulates adipocyte metabolism, adipose biology and vascular function, and hence may be a potential therapeutic target for metabolic disorders such as type 2 diabetes mellitus (T2DM) and the vascular complications associated with obesity and T2DM. The role of AMPK in PVAT or the actions of PVAT have yet to be established, however. Activation of AMPK by pharmacological agents, such as metformin and thiazolidinediones, may modulate the activity of PVAT surrounding blood vessels and thereby contribute to their beneficial effect in cardiometabolic diseases. This review will provide a current perspective on how PVAT may influence vascular function via AMPK. We will also attempt to demonstrate how modulating AMPK activity using pharmacological agents could be exploited therapeutically to treat cardiometabolic diseases.

Role of vascular oxidative stress in obesity and metabolic syndrome

Obesity is associated with vascular diseases that are often attributed to vascular oxidative stress. We tested the hypothesis that vascular oxidative stress could induce obesity. We previously developed mice that overexpress p22phox in vascular smooth muscle, tg(sm/p22phox), which have increased vascular ROS production. At baseline, tg(sm/p22phox) mice have a modest increase in body weight. With high-fat feeding, tg(sm/p22phox) mice developed exaggerated obesity and increased fat mass. Body weight increased from 32.16 ± 2.34 g to 43.03 ± 1.44 g in tg(sm/p22phox) mice (vs. 30.81 ± 0.71 g to 37.89 ± 1.16 g in the WT mice). This was associated with development of glucose intolerance, reduced HDL cholesterol, and increased levels of leptin and MCP-1. Tg(sm/p22phox) mice displayed impaired spontaneous activity and increased mitochondrial ROS production and mitochondrial dysfunction in skeletal muscle. In mice with vascular smooth muscle-targeted deletion of p22phox (p22phox(loxp/loxp)/tg(smmhc/cre) mice), high-fat feeding did not induce weight gain or leptin resistance. These mice also had reduced T-cell infiltration of perivascular fat. In conclusion, these data indicate that vascular oxidative stress induces obesity and metabolic syndrome, accompanied by and likely due to exercise intolerance, vascular inflammation, and augmented adipogenesis. These data indicate that vascular ROS may play a causal role in the development of obesity and metabolic syndrome.

Association between risk factors for vascular dementia and adiponectin

Vascular dementia is caused by various factors, including increased age, diabetes, hypertension, atherosclerosis, and stroke. Adiponectin is an adipokine secreted by adipose tissue. Adiponectin is widely known as a regulating factor related to cardiovascular disease and diabetes. Adiponectin plasma levels decrease with age. Decreased adiponectin increases the risk of cardiovascular disease and diabetes. Adiponectin improves hypertension and atherosclerosis by acting as a vasodilator and antiatherogenic factor. Moreover, adiponectin is involved in cognitive dysfunction via modulation of insulin signal transduction in the brain. Case-control studies demonstrate the association between low adiponectin and increased risk of stroke, hypertension, and diabetes. This review summarizes the recent findings on the association between risk factors for vascular dementia and adiponectin. To emphasize this relationship, we will discuss the importance of research regarding the role of adiponectin in vascular dementia.

Metabolic regulation by protein tyrosine phosphatases

Obesity and the metabolic syndrome and their associated morbidities are major public health issues, whose prevalence will continue to increase in the foreseeable future. Aberrant signaling by the receptors for leptin and insulin plays a pivotal role in development of the metabolic syndrome. More complete molecular-level understanding of how both of these key signaling pathways are regulated is essential for full characterization of obesity, the metabolic syndrome, and type II diabetes, and for developing novel treatments for these diseases. Phosphorylation of proteins on tyrosine residues plays a key role in mediating the effects of leptin and insulin on their target cells. Here, we discuss the molecular methods by which protein tyrosine phosphatases, which are key physiological regulators of protein phosphorylation in vivo, affect signaling by the leptin and insulin receptors in their major target tissues.

Anti-obesity and hypolipidaemic effects of Nelumbo nucifera seed ethanol extract in human pre-adipocytes and rats fed a high-fat diet

BACKGROUND

We conducted this investigation in order to examine the anti-obesity and hypolipidaemic effects of Nelumbo nucifera seed ethanol extract (NSEE) in vitro and in vivo.

METHODS

To study the anti-obesity effect of NSEE in vitro and in vivo, human pre-adipocytes were treated with NSEE, and male Sprague-Dawley rats were fed with a normal diet and a high-fat diet with or without NSEE, respectively.

RESULTS

In vitro treatment with NSEE resulted in inhibition of lipid accumulation and decreased expression of peroxisome proliferator-activated receptor gamma (PPARγ), glucose transporter 4 (GLUT4), and leptin in cultured human adipocytes, indicating that it inhibited the differentiation of pre-adipocytes into adipocytes. Administration of NSEE resulted in significantly reduced body weight gain and adipose tissue weights in rats. Serum triglyceride and leptin level of the high-fat diet + NSEE group was significantly lower, compared to the high-fat group.

CONCLUSION

These results demonstrate an inhibitory effect of NSEE on adipogenesis. In addition, NSEE had a beneficial effect, reducing adipose tissue weights, ameliorating blood lipid profile, and modulating serum leptin level in rats fed a high-fat diet. Therefore, we suggest that lotus seed has a potential to be developed as an effective agent against obesity-related diseases.

Ethanol extract of lotus (Nelumbo nucifera) root exhibits an anti-adipogenic effect in human pre-adipocytes and anti-obesity and anti-oxidant effects in rats fed a high-fat diet

Lotus (Nelumbo Nucifera) root, a well-known medicinal plant in Asia, is reported to have various therapeutic benefits, including anti-diabetes, anti-hypertension, and anti-hyperlipidaemia. We hypothesized that the ethanol extract of lotus root (ELR) would exhibit an anti-adipogenic effect in human pre-adipocytes as well as anti-obesity and anti-oxidant effects in rats fed a high-fat diet. Treatment with ELR in human pre-adipocytes resulted in inhibition of lipid accumulation and attenuated expression of adipogenic transcription factors such as peroxisome proliferator-activated receptor gamma and adipocyte marker genes, such as glucose transporter 4 and leptin. Administration of ELR resulted in a significant decrease in relative weights of adipose tissues in rats fed a high-fat diet. Consumption of a high-fat diet resulted in an increase in serum total cholesterol (TC) and triglyceride (TG) levels; however, administration of ELR resulted in a decrease in the levels of TC and TG. Administration of ELR resulted in a decrease in the level of serum leptin and insulin. Administration of ELR in rats fed a high-fat diet resulted in a decrease in hepatic thiobarbituric acid reactive substance content, elevated by a high-fat diet and an increase in superoxide dismutase activity and hepatic glutathione content. These results suggest that lotus root exerts anti-oxidant and anti-obesity effects and could be used as a functional and nutraceutical ingredient in combatting obesity-related diseases.

Ameliorative Effect of Hexane Extract of Phalaris canariensis on High Fat Diet-Induced Obese and Streptozotocin-Induced Diabetic Mice

Obesity is one of the major factors to increase various disorders like diabetes. The present paper emphasizes study related to the antiobesity effect of Phalaris canariensis seeds hexane extract (Al-H) in high-fat diet- (HFD-) induced obese CD1 mice and in streptozotocin-induced mild diabetic (MD) and severely diabetic (SD) mice.AL-H was orally administered to MD and SD mice at a dose of 400 mg/kg once a day for 30 days, and a set of biochemical parameters were studied: glucose, cholesterol, triglycerides, lipid peroxidation, liver and muscle glycogen, ALP, SGOT, SGPT, glucose-6-phosphatase, glucokinase, hexokinase, SOD, CAT, GSH, GPX activities, and the effect on insulin level. HS-H significantly reduced the intake of food and water and body weight loss as well as levels of blood glucose, serum cholesterol, triglyceride, lipoprotein, oxidative stress, showed a protective hepatic effect, and increased HDL-cholesterol, serum insulin in diabetic mice. The mice fed on the high-fat diet and treated with AL-H showed inhibitory activity on the lipid metabolism decreasing body weight and weight of the liver and visceral adipose tissues and cholesterol and triglycerides in the liver. We conclude that AL-H can efficiently reduce serum glucose and inhibit insulin resistance, lipid abnormalities, and oxidative stress in MD and SD mice. Our results demonstrate an antiobesity effect reducing lipid droplet accumulation in the liver, indicating that its therapeutic properties may be due to the interaction plant components soluble in the hexane extract, with any of the multiple targets involved in obesity and diabetes pathogenesis.

Metabolic syndrome--from the neurotrophic hypothesis to a theory

Metabolic syndrome (MetS) is a complex and heterogeneous disease characterized by central obesity, impaired glucose metabolism, dyslipidemia, arterial hypertension, insulin resistance and high-sensitivity C-reactive protein. In 2006, a neurotrophic hypothesis of the etiopathogenesis of MetS was launched. This hypothesis considered the neurotrophins a key factor in MetS development. Chronic inflammatory and/or psychoemotional distress provoke a series of neuroimmunoendocrine interactions such as increased tissue and plasma levels of proinflammatory cytokines and neurotrophins, vegetodystonia, disbalance of neurotransmitters, hormones and immunity markers, activation of the hypothalamo-pituitary-adrenal axis, insulin resistance, and atherosclerosis. An early and a late clinical stage in the course of MetS are defined. Meanwhile, evidence of supporting results from the world literature accumulates. This enables the transformation of the definition of the neurotrophic hypothesis into a neurotrophic theory of MetS. The important role of two neurotrophic factors, i.e. the nerve growth factor and brain-derived neurotrophic factor as well as of the proinflammatory cytokines, neurotransmitters, adipokines and, especially, of leptin for the development of MetS, obesity and type 2 diabetes mellitus is illustrated. There are reliable scientific arguments that the metabotrophic deficit due to reduced neurotrophins could be implicated in the pathogenesis of MetS, type 2 diabetes mellitus, and atherosclerosis as well. A special attention is paid to the activity of the hypothalamo-pituitary-adrenal axis after stress. The application of the neurotrophic theory of MetS could contribute to the etiological diagnosis and individualized management of MetS by eliminating the chronic distress, hyponeurotrophinemia and consequent pathology. It helps estimating the risk, defining the prognosis and implementing the effective prevention of this socially significant disease as evidenced by the dramatic recent growth of the world publication output on this interdisciplinary topic.

Phloretin and phlorizin promote lipolysis and inhibit inflammation in mouse 3T3-L1 cells and in macrophage-adipocyte co-cultures

SCOPE

Previous studies found that phloretin (PT) and phlorizin (PZ) could inhibit glucose transport, with PT being a better inhibitor of lipid peroxidation. This study aimed to evaluate the antiobesity effects of PT and PZ in 3T3-L1 cells and if they can modulate the relationship between adipocytes and macrophages.

METHODS AND RESULTS

Differentiated 3T3-L1 cells were treated with PT or PZ. Subsequently, transcription factors of adipogenesis and lipolysis proteins were measured. In addition, RAW 264.7 macrophages treated with PT or PZ were cultured in differentiated media from 3T3-L1 cells to analyze inflammatory mediators and signaling pathways. PT significantly enhanced glycerol release and inhibited the adipogenesis-related transcription factors. PT also promoted phosphorylation of AMP-activated protein kinase and increased activity of adipose triglyceride lipase and hormone-sensitive lipase. PT suppressed the nuclear transcription factor kappa-B and mitogen-activated protein kinase pathways when RAW 264.7 cells were cultured in differentiated media from 3T3-L1 cells. PZ improved lipolysis and inhibited the macrophage inflammatory response less effectively than PT.

CONCLUSION

This study suggests that PT is more effective than PZ at increasing lipolysis in adipocytes. In addition, PT also suppresses inflammatory response in macrophage that is stimulated by differentiated media from 3T3-L1 cells.

Chemerin connects fat to arterial contraction

OBJECTIVE

Obesity and hypertension are comorbid in epidemic proportion, yet their biological connection is largely a mystery. The peptide chemerin is a candidate for connecting fat deposits around the blood vessel (perivascular adipose tissue) to arterial contraction. We presently tested the hypothesis that chemerin is expressed in perivascular adipose tissue and is vasoactive, supporting the existence of a chemerin axis in the vasculature.

APPROACH AND RESULTS

Real-time polymerase chain reaction, immunohistochemistry, and Western analyses supported the synthesis and expression of chemerin in perivascular adipose tissue, whereas the primary chemerin receptor ChemR23 was expressed both in the tunica media and endothelial layer. The ChemR23 agonist chemerin-9 caused receptor, concentration-dependent contraction in the isolated rat thoracic aorta, superior mesenteric artery, and mesenteric resistance artery, and contraction was significantly amplified (more than 100%) when nitric oxide synthase was inhibited and the endothelial cell mechanically removed or tone was placed on the arteries. The novel ChemR23 antagonist CCX832 inhibited phenylephrine-induced and prostaglandin F2α-induced contraction (+perivascular adipose tissue), suggesting that endogenous chemerin contributes to contraction. Arteries from animals with dysfunctional endothelium (obese or hypertensive) demonstrated a pronounced contraction to chemerin-9. Finally, mesenteric arteries from obese humans demonstrate amplified contraction to chemerin-9.

CONCLUSIONS

These data support a new role for chemerin as an endogenous vasoconstrictor that operates through a receptor typically attributed to function only in immune cells.

Region-specific differences in brain melanocortin receptors in rats of the lean phenotype

The brain melanocortin (MC) system is one of numerous overlapping systems regulating energy balance; it consists of peptides including α-melanocyte-stimulating hormone that act through melanocortin receptors (MCRs). Mutations and polymorphisms in MC3R and MC4R have been identified as one of the most common genetic contributors to obesity in human studies. Brain MC3R and MC4R are known to modulate energy expenditure (EE) and food intake, but much less is known regarding brain MC5R. To test the hypothesis that brain MC modulates physical activity (PA) and EE, we compared brain MCR profiles in rats that consistently show high versus low levels of 'spontaneous' daily PA. Compared with low-activity rats, high-activity rats show enhanced mRNA expression of MCRs in the brain, specifically of MC3R in the paraventricular nucleus (PVN), and MC4R and MC5R in the perifornical lateral hypothalamus. Next, we microinjected the MCR agonist melanotan II into the PVN region and measured PA and EE. Intra-PVN melanotan II induced a dose-dependent increase in PA and this effect was greater in high-activity rats compared with low-activity rats. These results indicate region-specific brain MCR expression in the heightened PA seen in association with high endurance capacity and identify promising targets in the brain MC system that may contribute to interindividual variability in energy balance.