Adiponectin gene expression and adipocyte NF-kappaB transcriptional activity in elderly overweight and obese women: inter-relationships with fat distribution, hs-CRP, leptin and insulin resistance

Effects of Vitamin D Supplementation on Adipose Tissue Inflammation and NF-κB/AMPK Activation in Obese Mice Fed a High-Fat Diet

Adipose tissue expansion is strongly associated with increased adipose macrophage infiltration and adipocyte-derived pro-inflammatory cytokines, contributing to obesity-associated low-grade inflammation. Individuals with vitamin D deficiency have an increased prevalence of obesity and increased circulating inflammatory cytokines. However, the effect of vitamin D supplementation on obesity-induced inflammation remains controversial. Male C57BL/6J mice received a low-fat (10% fat) or high-fat (HF, 60% fat diet) containing 1000 IU vitamin D/kg diet, or HF supplemented with 10,000 IU vitamin D/kg diet for 16 weeks (n = 9/group). Vitamin D supplementation did not decrease HF-increased body weight but attenuated obesity-induced adipose hypertrophy and macrophage recruitment as demonstrated by the number of crown-like structures. Vitamin D supplementation significantly reduced the mRNA expression of CD11c, CD68, and iNOS, specific for inflammatory M1-like macrophages, and decreased serum levels of NO. In addition, significant reductions in pro-inflammatory gene expression of IL-6, MCP-1, and TNFα and mRNA levels of ASC-1, CASP1, and IL-1β involved in NLRP3 inflammasome were found in obese mice supplemented with vitamin D. Vitamin D supplementation significantly increased obesity-decreased AMPK activity and suppressed HF-increased NF-κB phosphorylation in adipose tissue from obese mice. These observed beneficial effects of vitamin D supplementation on adipose tissue expansion, macrophage recruitment, and inflammation might be related to AMPK/NF-κB signaling.

On the Immunometabolic Role of NF-κB in Adipocytes

Two decades of research have established that Nuclear Factor-κB (NF-κB) signaling plays a critical role in reprogramming the fat cell transcriptome towards inflammation in response to overnutrition and metabolic stress. Several groups have suggested that inhibition of NF-κB signaling could have metabolic benefits for obesity-associated adipose tissue inflammation. However, two significant problems arise with this approach. The first is how to deliver general NF-κB inhibitors into adipocytes without allowing these compounds to disrupt normal functioning in cells of the immune system. The second issue is that general inhibition of canonical NF-κB signaling in adipocytes will likely lead to a massive increase in adipocyte apoptosis under conditions of metabolic stress, leading full circle into a secondary inflammation (However, this problem may not be true for non-canonical NF-κB signaling.). This review will focus on the research that has examined canonical and non-canonical NF-κB signaling in adipocytes, focusing on genetic studies that examine loss-of-function of NF-κB specifically in fat cells. Although the development of general inhibitors of canonical NF-κB signaling seems unlikely to succeed in alleviating adipose tissue inflammation in humans, the door remains open for more targeted therapeutics. In principle, these would include compounds that interrogate NF-κB DNA binding, protein-protein interactions, or post-translational modifications that partition NF-κB activity towards some genes and away from others in adipocytes. I also discuss the possibility for inhibitors of non-canonical NF-κB signaling to realize success in mitigating fat cell dysfunction in obesity. To plant the seeds for such approaches, much biochemical “digging” in adipocytes remains; this includes identifying—in an unbiased manner–NF-κB direct and indirect targets, genomic DNA binding sites for all five NF-κB subunits, NF-κB protein-protein interactions, and post-translational modifications of NF-κB in fat cells.

Biosynthesis, total synthesis, structural modifications, bioactivity, and mechanism of action of the quinone-methide triterpenoid celastrol

Celastrol, a quinone-methide triterpenoid, was extracted from Tripterygium wilfordii Hook. F. in 1936 for the first time. Almost 70 years later, it is considered one of the molecules most likely to be developed into modern drugs, as it exhibits notable bioactivity, including anticancer and anti-inflammatory activity, and exerts antiobesity effects. In addition, the molecular mechanisms underlying its bioactivity are being widely studied, which offers new avenues for its development as a pharmaceutical reagent. Owing to its potential therapeutic effects and unique chemical structure, celastrol has attracted considerable interest in the fields of organic, biosynthesis, and medicinal chemistry. As several steps in the biosynthesis of celastrol have been revealed, the mechanisms of key enzymes catalyzing the formation and postmodifications of the celastrol scaffold have been gradually elucidated, which lays a good foundation for the future heterogeneous biosynthesis of celastrol. Chemical synthesis is also an effective approach to obtain celastrol. The total synthesis of celastrol was realized for the first time in 2015, which established a new strategy to obtain celastroid natural products. However, owing to the toxic effects and suboptimal pharmacological properties of celastrol, its clinical applications remain limited. To search for drug-like derivatives, several structurally modified compounds were synthesized and tested. This review focuses primarily on the latest research progress in the biosynthesis, total synthesis, structural modifications, bioactivity, and mechanism of action of celastrol. We anticipate that this paper will facilitate a more comprehensive understanding of this promising compound and provide constructive references for future research in this field.

EFFECTS OF EXENDIN-4 ON ENDOPLASMIC RETICULUM STRESS-MEDIATED INSULIN RESISTANCE IN 3T3-L1 ADIPOCYTES

Objective

Endoplasmic reticulum stress (ERS) is suspected as an important factor in the initiation of insulin resistance.

Aim

To explore the effects of exendin-4 (Ex-4) on the endoplasmic reticulum stress (ERS)-mediated insulin resistance in 3T3-L1 adipocytes. In our study, 3T3-L1 adipocytes were pre-treated with ERS inhibitors tauroursodeoxycholic acid (TUDCA), Ex-4 and an ERS inducer tunicamycin (TM) then induced insulin resistance. Glucose consumption of the adipocytes was measured. Western blots determined the protein levels of ERS markers and insulin signaling pathway.

Results

TM treatment reduced insulin-stimulated glucose consumption by 19.7% in 3T3-L1 adipocytes. This repression was blunted by 24h pre-treatment with TUDCA or Ex-4. Ex-4 augmented insulin-stimulated glucose consumption in adipocytes by 14.9%. Western blotting showed that TM treatment significantly increased the ER stress markers including p-IRE, p-JNK, p-PERK, p-eIF2a and ATF6 expression, whereas 24h pre-treatment of adipocytes with TUDCA or Ex-4 alleviated the ER stress. Ex-4 alleviates ERS-induced insulin resistance by upregulating the expression of phosphorylated Akt.

Conclusion

ERs mediates insulin resistance in 3T3-L1 adipocytes, and exendin-4 significantly improves this insulin resistance.

Functional Intronic Variant in the Retinoblastoma 1 Gene Underlies Broiler Chicken Adiposity by Altering Nuclear Factor-kB and SRY-Related HMG Box Protein 2 Binding Sites

The present study aimed to search for chicken abdominal fat deposition-related polymorphisms within RB1 and to provide functional evidence for significantly associated genetic variants. Association analyses showed that 11 single nucleotide polymorphisms (SNPs) in intron 17 of RB1, were significantly associated with both abdominal fat weight (P < 0.05) and abdominal fat percentage (P < 0.05). Functional analysis revealed that the A allele of g.32828A>G repressed the transcriptional efficiency of RB1 in vitro, through binding nuclear factor-kappa B (NF-_KB) and SRY-related HMG box protein 2 (SOX2). Furthermore, RB1 mRNA expression levels in the abdominal fat tissue of individuals with the A/A genotype of g.32828A>G were lower than those of individuals with the G/G genotype. Collectively, we propose that the intronic SNP g.32828A>G of RB1 is an obesity-associated variant that directly affects binding with NF-_KB and SOX2, leading to changes in RB1 expression which in turn may influence chicken abdominal fat deposition.

Acute Anaerobic Exercise Affects the Secretion of Asprosin, Irisin, and Other Cytokines - A Comparison Between Sexes

Objective: The new adipokine, which is asprosin, affects glucose release from the liver to the blood, and thus, influences exercise metabolism. This is the first study assessing whether single anaerobic exercise affects asprosin secretion in women and men.

Methods: 10 men and 10 women (aged 21.64 ± 1.22 and 22.64 ± 1.49, respectively) performed a single 20-s bicycle sprint. Blood samples were collected before exercise and in the 3′, 15′, 30′, and 60′ of recovery, and 24 h after competition.

Results: Only in women did asprosin (P = 0.001) (15′, 30′, 60′, and 24 h after exercise) and irisin (P < 0.001) (15′, 30′, and 60′) concentrations increase. Leptin, however, decreased (P = 0.001) at 3′, 15′, and 30′ in women. There was an increase in interleukin-6 (P < 0.001) at 3′, 15′, 30′, and 60′ of recovery in men, at 15′, 30′, 60′, and 24 h of recovery in women, along with a simultaneous decrease in interleukin-1β (P < 0.001) at 15′, 30′, and 60′ of recovery in men, and at 15′ and 30′ of recovery in women (r = -0.35, P < 0.001). There was a positive correlation between asprosin and adiponectin and a negative one between asprosin and leptin. The increase in irisin concentration at 30′ of recovery was positively correlated with the increase in asprosin concentration and percentage fat content, while being negatively correlated with total and lean body mass (LBM).

Conclusion: The single anaerobic effort induced an increase in asprosin and irisin secretion while reducing leptin secretion in women. Adipocytokine concentration changes are inter-related. Regardless of sex, anaerobic efforts induce anti-inflammatory effects.

NF-κβ: A Potential Target in the Management of Vascular Complications of Diabetes

Diabetes is a metabolic disorder affecting large percentage of population worldwide. NF-κβ plays key role in pathogenesis of vascular complications of diabetes. Persistent hyperglycemia activates NF-κβ that triggers expression of various cytokines, chemokines and cell adhesion molecules. Over-expression of TNF-α, interleukins, TGF-β, Bcl2 and other pro-inflammatory proteins and pro-apoptotic genes by NF-κβ is key risk factor in vascular dysfunction. NF-κβ over-expression also triggers calcification of endothelial cells leading to endothelial dysfunction and further vascular complications. Inhibition of NF-κβ pro-inflammatory pathway is upcoming novel target for management of vascular complications of diabetes. Various natural and synthetic inhibitors of NF-κβ have been studied in management of diabetic complications. Recent preclinical and clinical studies validate NF-κβ as promising target in the management of vascular complications of diabetes.

Relationship between family history of type 2 diabetes and serum FGF21

BACKGROUND

Determining predictive markers for the development of type 2 diabetes (T2D), particularly in young individuals, offers immense potential benefits in preventative medicine. Previous research examining serum fibroblast growth factor 21 (FGF21) in humans has revealed equivocal relationships with clinical markers of metabolic dysfunction. However, it is unknown to what extent, if any, first-degree family history of T2D (mother or father of the participant diagnosed with T2D) level affects serum FGF21 levels. The aim of this study was to determine whether in healthy individuals with FH+ (n = 18) and without FH- (n = 17) a family history of T2D affects serum FGF21.

MATERIALS AND METHODS

Fasting serum and clinical, metabolic and anthropometric measures were determined using a cross-sectional design.

RESULTS

Differences between groups for FGF21 were not significant (FH+ = 266 pg/mL ± 51·4, FH = 180 pg/mL ± 29; Z = 0·97, P = 0·33). Adiponectin values were lower in FH+ (8·81 μg/mL ± 2·14) compared to FH- (10·65 μg/mL ± 1·44; F = 8·83, P = 0·01). Resistin was negatively correlated with FGF21 for all participants (r = -0·38, P = 0·03), but no other clinical, metabolic, or serum markers were predictive for serum FGF21 in FH+ or FH-.

CONCLUSIONS

Serum FGF21 is not significantly different between FH+ and FH- in young, healthy individuals. Based upon the data of this pilot study, it is unclear whether serum FGF21 can be used as a stand-alone predictive marker for T2D in healthy subjects.

Markers of Adipogenesis, but Not Inflammation, in Adipose Tissue Are Independently Related to Insulin Sensitivity

CONTEXT

In obesity, adipose tissue (AT) undergoes dynamic remodeling, including an alternation in adipogenesis, AT-resident cell content, angiogenesis, and turnover of extracellular matrix (ECM) components. Studies of AT in humans have been carried out mostly in people with severe metabolic abnormalities, like type 2 diabetes or morbid obesity.

OBJECTIVE

The purpose of this study was to investigate subcutaneous AT gene expression of markers of adipogenesis, ECM remodeling, and inflammation in young, healthy, overweight or obese subjects.

DESIGN

The study group comprised 83 normal-weight, 48 overweight, and 19 obese subjects. Euglycemic hyperinsulinemic clamp, biopsy of subcutaneous AT, and isolation of peripheral blood mononuclear cells (PBMCs) were performed. Gene expression was measured with real-time polymerase chain reaction.

RESULTS

Overweight/obese subjects had lower AT expression of markers of adipogenesis, insulin signaling, and angiogenesis; higher expression of markers of ECM remodeling; altered expression of genes of the nuclear factor-κ-B (NFκB), but not c-Jun NH2-terminal kinase, pathway; and higher expression of macrophage markers but not markers of other immune cells. In multiple regression analysis, the expression of CEBPA, ADIPOQ, IRS1, IRS2, SLC2A4, and MMP9 was associated with insulin sensitivity independently of body mass index. No differences were found in inflammatory-gene PBMC expression.

CONCLUSION

Overweight/obesity is associated with altered expression of genes of adipogenesis, insulin signaling, ECM remodeling, and inflammation. NFκB seems to be the earliest inflammatory pathway altered at the transcriptional level in AT. Macrophages seem to be the first immune cells to infiltrate AT. Adipogenesis and ECM remodeling are the initial processes in AT that are independently associated with insulin sensitivity.

Protectin DX ameliorates palmitate- or high-fat diet-induced insulin resistance and inflammation through an AMPK-PPARα-dependent pathway in mice

Protectin DX (PDX), a double lipoxygenase derivative of docosahexaenoic acid, has been reported to attenuate inflammation and insulin resistance. In the current study, we explored the effects of PDX on hyperlipidemia-induced insulin resistance and inflammation through AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor α (PPARα). PDX attenuated the impairment of insulin receptor substrate 1/Akt-mediated insulin signaling in palmitate-treated differentiated C2C12 cells and soleus skeletal muscle of HFD-fed mice. Furthermore, PDX treatment significantly ameliorated HFD-induced weight gain and improved glucose tolerance in mice. Nuclear factor kB nuclear translocation, inhibitory kBα phosphorylation, and expression of proinflammatory cytokines were markedly attenuated by PDX in both in vitro and in vivo models. PDX treatment markedly augmented AMPK phosphorylation and PPARα expression in C2C12 cells and in skeletal muscle of mice. AMPK- and PPARα-specific siRNAs significantly abrogated the suppressive effects of PDX on palmitate-induced insulin resistance and inflammation. Furthermore, PDX markedly stimulated the expression of genes related to fatty acid oxidation. These effects of PDX were significantly suppressed by AMPK and PPARα siRNAs. In conclusion, our results demonstrate that PDX ameliorates insulin resistance and inflammation and stimulates fatty acid oxidation through AMPK- and PPARα-mediated pathways in skeletal muscle.

Interactions of exercise training and high-fat diet on adiponectin forms and muscle receptors in mice

Background

Metabolic syndrome (MetS) is characterized by systemic disturbances that increase cardiovascular risk. Adiponectin (Ad) exhibits a cardioprotective function because of its anti-inflammatory and anti-atherosclerotic properties. In the bloodstream, this adipocytokine circulates on multimers (Ad_mer), among which high molecular weight (HMW) are the most active forms. Because alterations of Ad plasmatic levels, Ad_mer distribution and receptor (AdipoR) expression have been described in murine models and obese patients, strategies that aim to enhance Ad production or its effect on target tissues are the subject of intense investigations. While exercise training is well known to be beneficial for reducing cardiovascular risk, the contribution of Ad is still controversial. Our aim was to evaluate the effect of exercise training on Ad production, Ad_mer distribution and AdipoR muscle expression in a murine model of MetS.

Methods

At 6 weeks of age, mice were submitted to a standard (SF) or high-fat high-sugar (HF) diet for 10 weeks. After 2 weeks, the SF- and HF-fed animals were randomly assigned to a training program (SFT, HFT) or not (SFC, HFC). The trained groups were submitted to sessions of running on a treadmill 5 days a week.

Results and conclusions

The HF mice presented the key problems associated with MetS (increased caloric intake, body weight, glycemia and fat mass), a change in Ad_mer distribution in favor of the less-active forms and increased AdipoR2 expression in muscle. In contrast, exercise training reversed some of the adverse effects of a HF diet (increased glucose tolerance, better caloric intake control) without any modifications in Ad production and Ad_mer distribution. However, increased AdipoR1 muscle expression was observed in trained mice, but this effect was hampered by HF diet. These data corroborate a recent hypothesis suggesting a functional divergence between AdipoR1 and AdipoR2, with AdipoR1 having the predominant protective action on metabolic function.

Electronic supplementary material

The online version of this article (doi:10.1186/s12986-016-0138-2) contains supplementary material, which is available to authorized users.

Expression of candidate genes associated with obesity in peripheral white blood cells of Mexican children

INTRODUCTION

Obesity is a chronic, complex, and multifactorial disease, characterized by excess body fat. Diverse studies of the human genome have led to the identification of susceptibility genes that contribute to obesity. However, relatively few studies have addressed specifically the association between the level of expression of these genes and obesity.

MATERIAL AND METHODS

We studied 160 healthy and obese unrelated Mexican children aged 6 to 14 years. We measured the transcriptional expression of 20 genes associated with obesity, in addition to the biochemical parameters, in peripheral white blood cells. The detection of mRNA levels was performed using the OpenArray Real-Time PCR System (Applied Biosystems).

RESULTS

Obese children exhibited higher values of fasting glucose (p = 0.034), fasting insulin (p = 0.004), low-density lipoprotein (p = 0.006), triglycerides (p < 0.001), systolic blood pressure and diastolic blood pressure (p < 0.001), and lower values of high-density lipoprotein (p < 0.001) compared to lean children. Analysis of transcriptional expression data showed a difference for ADRB1 (p = 0.0297), ADIPOR1 (p = 0.0317), GHRL (p = 0.0060) and FTO (p = 0.0348) genes.

CONCLUSIONS

Our results suggest that changes in the expression level of the studied genes are involved in biological processes implicated in the development of childhood obesity. Our study contributes new perspectives for a better understanding of biological processes involved in obesity. The protocol was approved by the National Committee and Ethical Committee Board from the Mexican Social Security Institute (IMSS) (IMSS FIS/IMSS/PRIO/10/011).

Milk-derived tripeptides IPP (Ile-Pro-Pro) and VPP (Val-Pro-Pro) promote adipocyte differentiation and inhibit inflammation in 3T3-F442A cells

Milk derived tripeptides IPP (Ile-Pro-Pro) and VPP (Val-Pro-Pro) have shown promise as anti-hypertensive agents due to their inhibitory effects on angiotensin converting enzyme (ACE). Due to the key inter-related roles of hypertension, chronic inflammation and insulin resistance in the pathogenesis of metabolic syndrome, there is growing interest in investigating established anti-hypertensive agents for their effects on insulin sensitivity and inflammation. In this study, we examined the effects of IPP and VPP on 3T3-F442A murine pre-adipocytes, a widely used model for studying metabolic diseases. We found that both IPP and VPP induced beneficial adipogenic differentiation as manifested by intracellular lipid accumulation, upregulation of peroxisome proliferator-activated receptor gamma (PPARγ) and secretion of the protective lipid hormone adiponectin by these cells. The observed effects were similar to those induced by insulin, suggesting potential benefits in the presence of insulin resistance. IPP and VPP also inhibited cytokine induced pro-inflammatory changes such as reduction in adipokine levels and activation of the nuclear factor kappa B (NF-κB) pathway. Taken together, our findings suggest that IPP and VPP exert insulin-mimetic adipogenic effects and prevent inflammatory changes in adipocytes, which may offer protection against metabolic disease.

Insulin resistance pathogenesis in metabolic obesity

In this review we discuss the molecular mechanisms of insulin resistance concomitant with metabolic inflammation. We also analyze the world results of experimental and clinical studies which aimed at identifying the molecular targets for the development of new prevention and treatment of insulin resistance.

Acerola (Malpighia emarginata DC.) juice intake protects against alterations to proteins involved in inflammatory and lipolysis pathways in the adipose tissue of obese mice fed a cafeteria diet

BACKGROUND

Obesity has been studied as a metabolic and an inflammatory disease and is characterized by increases in the production of pro-inflammatory adipokines in the adipose tissue.To elucidate the effects of natural dietary components on the inflammatory and metabolic consequences of obesity, we examined the effects of unripe, ripe and industrial acerola juice (Malpighia emarginata DC.) on the relevant inflammatory and lipolysis proteins in the adipose tissue of mice with cafeteria diet-induced obesity.

MATERIALS/METHODS

Two groups of male Swiss mice were fed on a standard diet (STA) or a cafeteria diet (CAF) for 13 weeks. Afterwards, the CAF-fed animals were divided into five subgroups, each of which received a different supplement for one further month (water, unripe acerola juice, ripe acerola juice, industrial acerola juice, or vitamin C) by gavage. Enzyme-linked immunosorbent assays, Western blotting, a colorimetric method and histology were utilized to assess the observed data.

RESULTS

The CAF water (control obese) group showed a significant increase in their adiposity indices and triacylglycerol levels, in addition to a reduced IL-10/TNF-α ratio in the adipose tissue, compared with the control lean group. In contrast, acerola juice and Vitamin C intake ameliorated the weight gain, reducing the TAG levels and increasing the IL-10/TNF-α ratio in adipose tissue. In addition, acerola juice intake led to reductions both in the level of phosphorylated JNK and to increases in the phosphorylation of IκBα and HSLser660 in adipose tissue.

CONCLUSIONS

Taken together, these results suggest that acerola juice reduces low-grade inflammation and ameliorates obesity-associated defects in the lipolytic processes.

Favorable modulation of benign breast tissue and serum risk biomarkers is associated with > 10 % weight loss in postmenopausal women

We conducted a phase II feasibility study of a 6-month behavioral weight loss intervention in postmenopausal overweight and obese women at increased risk for breast cancer and the effects of weight loss on anthropomorphic, blood, and benign breast tissue biomarkers. 67 women were screened by random peri-areolar fine-needle aspiration, 27 were registered and 24 participated in the interventional phase. The 24 biomarker evaluable women had a median baseline BMI of 34.2 kg/m(2) and lost a median of 11 % of their initial weight. Significant tissue biomarker modulation after the 6-month intervention was noted for Ki-67 (if restricted to the 15 women with any Ki-67 at baseline, p = 0.041), adiponectin to leptin ratio (p = 0.003); and cyclin B1 (p = 0.001), phosphorylated retinoblastoma (p = 0.005), and ribosomal S6 (p = 0.004) proteins. Favorable modulation for serum markers was observed for sex hormone-binding globulin (p < 0.001), bioavailable estradiol (p < 0.001), bioavailable testosterone (p = 0.033), insulin (p = 0.018), adiponectin (p = 0.001), leptin (p < 0.001), the adiponectin to leptin ratio (p < 0.001), C-reactive protein (p = 0.002), and hepatocyte growth factor (p = 0.011). When subdivided by <10 or >10 % weight loss, change in percent total body and android (visceral) fat, physical activity, and the majority of the serum and tissue biomarkers were significantly modulated only for women with >10 % weight loss from baseline. Some factors such as serum PAI-1 and breast tissue pS2 (estrogen-inducible gene) mRNA were not significantly modulated overall but were when considering only those with >10 % weight loss. In conclusion, a median weight loss of 11 % over 6 months resulted in favorable modulation of a number of anthropomorphic, breast tissue and serum risk and mechanistic markers. Weight loss of 10 % or more should likely be the goal for breast cancer risk reduction studies in obese women.

Mechanisms of chronic state of inflammation as mediators that link obese adipose tissue and metabolic syndrome

The metabolic syndrome is a cluster of cardiometabolic alterations that include the presence of arterial hypertension, insulin resistance, dyslipidemia, and abdominal obesity. Obesity is associated with a chronic inflammatory response, characterized by abnormal adipokine production, and the activation of proinflammatory signalling pathways resulting in the induction of several biological markers of inflammation. Macrophage and lymphocyte infiltration in adipose tissue may contribute to the pathogenesis of obesity-mediated metabolic disorders. Adiponectin can either act directly on macrophages to shift polarization and/or prime human monocytes into alternative M2-macrophages with anti-inflammatory properties. Meanwhile, the chronic inflammation in adipose tissue is regulated by a series of transcription factors, mainly PPARs and C/EBPs, that in conjunction regulate the expression of hundreds of proteins that participate in the metabolism and storage of lipids and, as such, the secretion by adipocytes. Therefore, the management of the metabolic syndrome requires the development of new therapeutic strategies aimed to alter the main genetic pathways involved in the regulation of adipose tissue metabolism.

Mechanisms of chronic state of inflammation as mediators that link obese adipose tissue and metabolic syndrome

The metabolic syndrome is a cluster of cardiometabolic alterations that include the presence of arterial hypertension, insulin resistance, dyslipidemia, and abdominal obesity. Obesity is associated with a chronic inflammatory response, characterized by abnormal adipokine production, and the activation of proinflammatory signalling pathways resulting in the induction of several biological markers of inflammation. Macrophage and lymphocyte infiltration in adipose tissue may contribute to the pathogenesis of obesity-mediated metabolic disorders. Adiponectin can either act directly on macrophages to shift polarization and/or prime human monocytes into alternative M2-macrophages with anti-inflammatory properties. Meanwhile, the chronic inflammation in adipose tissue is regulated by a series of transcription factors, mainly PPARs and C/EBPs, that in conjunction regulate the expression of hundreds of proteins that participate in the metabolism and storage of lipids and, as such, the secretion by adipocytes. Therefore, the management of the metabolic syndrome requires the development of new therapeutic strategies aimed to alter the main genetic pathways involved in the regulation of adipose tissue metabolism.

Celastrol, an NF-κB inhibitor, improves insulin resistance and attenuates renal injury in db/db mice

The NF-κB pathway plays an important role in chronic inflammatory and autoimmune diseases. Recently, NF-κB has also been suggested as an important mechanism linking obesity, inflammation, and metabolic disorders. However, there is no current evidence regarding the mechanism of action of NF-κB inhibition in insulin resistance and diabetic nephropathy in type 2 diabetic animal models. We investigated the effects of the NF-κB inhibitor celastrol in db/db mice. The treatment with celastrol for 2 months significantly lowered fasting plasma glucose (FPG), HbA1C and homeostasis model assessment index (HOMA-IR) levels. Celastrol also exhibited significant decreases in body weight, kidney/body weight and adiposity. Celastrol reduced insulin resistance and lipid abnormalities and led to higher plasma adiponectin levels. Celastrol treatment also significantly mitigated lipid accumulation and oxidative stress in organs including the kidney, liver and adipose tissue. The treated group also exhibited significantly lower creatinine levels and urinary albumin excretion was markedly reduced. Celastrol treatment significantly lowered mesangial expansion and suppressed type IV collagen, PAI-1 and TGFβ1 expressions in renal tissues. Celastrol also improved abnormal lipid metabolism, oxidative stress and proinflammatory cytokine activity in the kidney. In cultured podocytes, celastrol treatment abolished saturated fatty acid-induced proinflammatory cytokine synthesis. Taken together, celastrol treatment not only improved insulin resistance, glycemic control and oxidative stress, but also improved renal functional and structural changes through both metabolic and anti-inflammatory effects in the kidney. These results suggest that targeted therapy for NF-κB may be a useful new therapeutic approach for the management of type II diabetes and diabetic nephropathy.

Wild blueberry (Vaccinium angustifolium) consumption improves inflammatory status in the obese Zucker rat model of the metabolic syndrome

The metabolic syndrome (MetS) is a major public health problem in the United States. Chronic inflammation is a critical component of the MetS, leading to dramatically increased risk of type II diabetes and cardiovascular disease. This study investigates the ability of a wild-blueberry-enriched diet to improve the proinflammatory status associated with MetS in the obese Zucker rat (OZR). Circulating levels of key inflammatory markers and their expression in the liver and abdominal adipose tissue were examined in OZR and its genetic control, the lean Zucker rat (LZR), after feeding a control or an 8% wild blueberry diet (WB) for 8 weeks from age 8 to 16 weeks. In the OZR, WB consumption resulted in decreased plasma concentrations of tumor necrosis factor (TNF)-α (-25.6%, P<.05), interleukin (IL)-6 (-14.9%, P<.05) and C-reactive protein (CRP) (-13.1%, P<.05) and increased adiponectin concentration (+21.8%, P<.05). Furthermore, expression of IL-6, TNF-α and nuclear factor (NF)-kB was down-regulated in both the liver (-65%, -59% and -25%, respectively) and the abdominal adipose tissue (-64%, -52% and -65%), while CRP expression was down-regulated only in the liver (-25%). In the abdominal adipose tissue, similar trends were also observed in LZR following WB treatment, with decreased liver expression of NF-kB, CRP, IL-6 and TNF-α (-24%, -16%, -21% and -50%) and increased adiponectin expression (+25%). Results of this study suggest that wild blueberry consumption exerts an overall anti-inflammatory effect in the OZR, a model of the metabolic syndrome.

Biglycan deletion alters adiponectin expression in murine adipose tissue and 3T3-L1 adipocytes

Obesity promotes increased secretion of a number of inflammatory factors from adipose tissue. These factors include cytokines and very lately, extracellular matrix components (ECM). Biglycan, a small leucine rich proteoglycan ECM protein, is up-regulated in obesity and has recently been recognized as a pro-inflammatory molecule. However, it is unknown whether biglycan contributes to adipose tissue dysfunction. In the present study, we characterized biglycan expression in various adipose depots in wild-type mice fed a low fat diet (LFD) or obesity-inducing high fat diet (HFD). High fat feeding induced biglycan mRNA expression in multiple adipose depots. Adiponectin is an adipokine with anti-inflammatory and insulin sensitizing effects. Due to the importance of adiponectin, we examined the effect of biglycan on adiponectin expression. Comparison of adiponectin expression in biglycan knockout (bgn(-/0)) and wild-type (bgn(+/0)) reveals higher adiponectin mRNA and protein in epididymal white adipose tissue in bgn(-/0) mice, as well higher serum concentration of adiponectin, and lower serum insulin concentration. On the contrary, knockdown of biglycan in 3T3-L1 adipocytes led to decreased expression and secretion of adiponectin. Furthermore, treatment of 3T3-L1 adipocytes with conditioned medium from biglycan treated macrophages resulted in an increase in adiponectin mRNA expression. These data suggest a link between biglycan and adiponectin expression. However, the difference in the pattern of regulation between in vivo and in vitro settings reveals the complexity of this relationship.

Adipose tissue inflammation and cancer cachexia: possible role of nuclear transcription factors

Cancer cachexia is a multifaceted syndrome whose aetiology is extremely complex and is directly related to poor patient prognosis and survival. Changes in lipid metabolism in cancer cachexia result in marked reduction of total fat mass, increased lipolysis, total oxidation of fatty acids, hyperlipidaemia, hypertriglyceridaemia, and hypercholesterolaemia. These changes are believed to be induced by inflammatory mediators, such as tumour necrosis factor-α (TNF-α) and other factors. Attention has recently been drawn to the current theory that cachexia is a chronic inflammatory state, mainly caused by the host's reaction to the tumour. Changes in expression of numerous inflammatory mediators, notably in white adipose tissue (WAT), may trigger several changes in WAT homeostasis. The inhibition of adipocyte differentiation by PPARγ is paralleled by the appearance of smaller adipocytes, which may partially account for the inhibitory effect of PPARγ on inflammatory gene expression. Furthermore, inflammatory modulation and/or inhibition seems to be dependent on the IKK/NF-κB pathway, suggesting that a possible interaction between NF-κB and PPARγ is required to modulate WAT inflammation induced by cancer cachexia. In this article, current literature on the possible mechanisms of NF-κB and PPARγ regulation of WAT cells during cancer cachexia are discussed. This review aims to assess the role of a possible interaction between NF-κB and PPARγ in the setting of cancer cachexia as well as its significant role as a potential modulator of chronic inflammation that could be explored therapeutically.

The anti-inflammatory action of fermented soybean products in kidney of high-fat-fed rats

Soybean has many compounds with a variety of biological properties that potentially benefit human health; among them, isoflavones have inhibitory effects on lipid oxidation in adipose tissue. In this study, we examined two Korean traditional fermented soybean products--doenjang (DNJ) and cheonggukjang (CGJ)--for their ability to suppress redox-sensitive nuclear factor κB (NF-κB) activation in the kidney of rats fed a high-fat diet. Sprague-Dawley rats, 4 weeks old, were fed soybean, DNJ, or CGJ (1 g/kg/day) with a 20% fat diet for 6 weeks. Body weight and food intake were carefully monitored. NF-κB-related activities of genes for inflammatory proteins, such as inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and vascular cell adhesion molecule-1 (VCAM-1), were determined. The soybean products exhibited antioxidative action by maintaining redox regulation, suppressing NF-κB activation, and modulating the expression of genes for NF-κB-induced inflammatory proteins such as COX-2, iNOS, and VCAM-1. Based on these results, we conclude that Korean traditional soybean fermented products, especially CGJ, suppress the generation of reactive species, NF-κB activity, and NF-κB-related inflammatory genes.

In vitro study of the effect of diesterified alkoxyglycerols with conjugated linoleic acid on adipocyte inflammatory mediators

Background

Adipocytes contribute to inflammation and the innate immune response through expression of inflammatory mediators. High levels of these mediators have been related to chronic inflammation state and insulin resistance, cardiovascular diseases and diabetes type 2, among other disorders. 3-octadecylglycerol (batyl alcohol) has been described as an inflammatory agent, whereas Conjugated Linoleic Acid (CLA) is considered effective against obesity. In this study we examined the anti-inflammatory activity and mechanisms of modified alkoxyglycerols. Tumor necrosis factor (TNF-α) activated mature adipocytes were used as cellular model of inflammation. Secreted levels and gene expressions of some inflammatory mediators, such as the adipokines, interleukin (IL)-1β, IL-6 and IL-10; and the levels of leptin and adiponectin hormones were quantified in presence and absence of alkoxyglycerols and when human adipocyte cells were or not activated by TNF-α. The aim of this study is to describe the effects of nonesterified alkoxyglycerols, CLA and diesterified alkoxyglycerols with CLA (DEA-CLA) and check if they present beneficial properties using an in vitro model of some chronic diseases related to the inflammatory process, such as obesity, using human mature adipocytes activated with TNF-α.

Results

Our data suggest that DEA-CLA, product of the esterification between the CLA and batyl alcohol, present beneficial effects on adipocytes close to observed and described for CLA (i.e. decrease of IL-1β) and no adverse effects as observed for batyl alcohol (i.e. decrease of IL-10). In addition, DEA-CLA presented similar activity to CLA showing a trend to increase the secreted levels of adiponectin and decreasing the secreted levels of leptin.

Conclusions

CLA and DEA-CLA modify adipocyte inflammatory mediators and also could play a role on energy homeostasis through depletion of leptin levels.

The use of LeptiCore in reducing fat gain and managing weight loss in patients with metabolic syndrome

Background

LeptiCore^® is a proprietary combination of various ingredients which have been shown to have properties which could be beneficial to weight loss in obese and overweight human subjects. This study evaluates the effect of Lepticore^® on bodyweight as well as parameters associated with obesity and metabolic syndrome.

Methods

The study was an 8 week randomized, double-blind, placebo-controlled design involving 92 obese (mean BMI > 30 kg/m²) participants (37 males; 55 females; ages 19-52; mean age = 30.7). The participants were randomly divided into three groups: placebo (n = 30), LeptiCore^® formula A (low dose) (n = 31) and LeptiCore^® formula B (high dose) (n = 31). Capsules containing the placebo or active formulations were administered twice daily before meals with 300 ml of water. None of the participants followed any specific diet nor took any weight-reducing medications for the duration of the study. A total of 12 anthropomorphic and serological measurements were taken at the beginning of the study and after 2, 4, 6, and 8 weeks of treatment.

Results

Compared to the placebo group, the two active groups showed statistically significant differences on all 12 variables by week 8. These included four anthropomorphic variables (body weight, body fat, waist and hip size) and eight measures of serological levels (plasma total cholesterol, LDL, HDL, triglycerides, blood glucose, serotonin, leptin, C-reactive protein). The two active groups also showed significant intra-group differences on all 12 variables between study onset and week 8.

Conclusion

The LeptiCore^® formulation at both the low and high dosages appears to be helpful in the management of fat gain and its related complications. The higher dosage resulted in significantly greater reductions in body weight and triglyceride, blood glucose, and C-reactive protein levels, as well as increased serotonin levels.

Changes in adiponectin multimer distribution in response to atorvastatin treatment in patients with type 2 diabetes

OBJECTIVE

Multimeric high molecular weight (HMW) forms of adiponectin were previously shown to be inversely associated with the extent of atherosclerosis in males and are down-regulated in patients with the metabolic syndrome and type 2 diabetes. In this study, potential influences of atorvastatin therapy on adiponectin multimer distribution were studied in patients with type 2 diabetes.

DESIGN, PATIENTS AND MEASUREMENTS

The effect of 40 mg atorvastatin on HMW, medium molecular weight (MMW), and low molecular weight (LMW) isoforms of adiponectin were investigated in 75 patients (23 females; 52 males) with type 2 diabetes in an 8-week-long, placebo-controlled and randomized study. Adiponectin multimeric isoforms were detected by Western blot analysis.

RESULTS

After atorvastatin therapy the median serum concentration of HMW adiponectin increased significantly by 42.3% (1.68 vs. 2.39 microg/ml; P < 0.001), while concentrations of MMW adiponectin and LMW adiponectin significantly decreased by 20.8% and 23.2%, respectively (MMW: 3.31 vs. 2.62 microg/ml, P = 0.047; LMW: 0.56 vs. 0.43 microg/ml, P = 0.033). Median total adiponectin levels were not significantly altered by atorvastatin treatment (6.0 vs. 6.2 microg/ml, P = 0.898). Consequently, the HMW: total-adiponectin ratio significantly increased by 25.0% (0.40 vs. 0.50; P = 0.013).

CONCLUSIONS

Atorvastatin therapy is associated with significant changes in adiponectin multimer distribution in patients with type 2 diabetes. Since total adiponectin levels were not affected by intervention, atorvastatin may shift adiponectin size towards the HMW form.

c-Jun NH2-terminal kinase activity in subcutaneous adipose tissue but not nuclear factor-kappaB activity in peripheral blood mononuclear cells is an independent determinant of insulin resistance in healthy individuals

OBJECTIVE

Chronic low-grade activation of the immune system (CLAIS) predicts type 2 diabetes via a decrease in insulin sensitivity. Our study investigated potential relationships between nuclear factor-kappaB (NF-kappaB) and c-Jun NH(2)-terminal kinase (JNK) pathways-two pathways proposed as the link between CLAIS and insulin resistance.

RESEARCH DESIGN AND METHODS

Adiposity (dual-energy X-ray absorptiometry), waist-to-hip ratio (WHR), and insulin sensitivity (M, hyperinsulinemic-euglycemic clamp) were measured in 22 healthy nondiabetic volunteers (aged 29 +/- 11 years, body fat 28 +/- 11%). NF-kappaB activity (DNA-binding assay) and JNK1/2 activity (phosphorylated JNK) were assessed in biopsies of the vastus lateralis muscle and subcutaneous adipose tissue and in peripheral blood mononuclear cell (PBMC) lysates.

RESULTS

NF-kappaB activities in PBMCs and muscle were positively associated with WHR after adjustment for age, sex, and percent body fat (both P < 0.05). NF-kappaB activity in PBMCs was inversely associated with M after adjustment for age, sex, percent body fat, and WHR (P = 0.02) and explained 16% of the variance of M. There were no significant relationships between NF-kappaB activity and M in muscle or adipose tissue (both NS). Adipose-derived JNK1/2 activity was not associated with obesity (all P> 0.1), although it was inversely related to M (r = -0.54, P < 0.05) and explained 29% of its variance. When both NF-kappaB and JNK1/2 were examined statistically, only JNK1/2 activity in adipose tissue was a significant determinant of insulin resistance (P = 0.02).

CONCLUSIONS

JNK1/2 activity in adipose tissue but not NF-kappaB activity in PBMCs is an independent determinant of insulin resistance in healthy individuals.

Altered signalling and gene expression associated with the immune system and the inflammatory response in obesity

White adipose tissue functions not only as an energy store but also as an important endocrine organ and is involved in the regulation of many pathological processes. The obese state is characterised by a low-grade systemic inflammation, mainly a result of increased adipocyte as well as fat resident- and recruited-macrophage activity. In the past few years, various products of adipose tissue including adipokines and cytokines have been characterised and a number of pathways linking adipose tissue metabolism with the immune system have been identified. In obesity, the pro- and anti-inflammatory effects of adipokines and cytokines through intracellular signalling pathways mainly involve the nuclear factor kappa B (NF-kappaB) and the Jun N-terminal kinase (JNK) systems as well as the I kappa B kinase beta (IKK-beta). Mitogen-activated protein kinase (MAPK) and extracellular-signal-regulated kinase (ERK) pathways, which lead to signal transducer and activator of transcription 3 (STAT3) activation, are also important in the production of pro-inflammatory cytokines. Obesity increases the expression of leptin and other cytokines, as well as some macrophage and inflammatory markers, and decreases adiponectin expression in adipose tissue. A number of cytokines, e.g. tumour necrosis factor alpha (TNF-alpha) and monocyte chemotactic protein 1 (MCP-1), and some pro-inflammatory interleukins, leuckocyte antigens, chemochines, surface adhesion molecules and metalloproteases are up-regulated whereas other factors are down-regulated. The present paper will focus on the molecular mechanisms linking obesity and inflammation with emphasis on the alteration of signalling and gene expression in adipose cell components.

The emerging role of adipokines as mediators of cardiovascular function: physiologic and clinical perspectives

Interest in the biology of white adipose tissue has increased dramatically since the discovery of leptin in 1994. The identification of the product of the gene obese (ob) threw light on the role of adipose tissue in the physiopathology of obesity-related diseases and spurred the identification of numerous other adipokines, many of a proinflammatory nature. It has become increasingly evident that white adipose tissue-derived cytokines mediate between obesity-related exogenous factors (nutrition and lifestyle) and the molecular events that lead to metabolic syndrome, inflammation, and cardiovascular diseases. Here we review recent adipokine research, with particular attention to the roles of adiponectin, leptin, resistin, visfatin, apelin, omentin, and chemerin in such conditions.