Adiponectin induces the anti-inflammatory cytokines IL-10 and IL-1RA in human leukocytes

Role of gut microbiota and oxidative stress in the progression of non-alcoholic fatty liver disease to hepatocarcinoma: Current and innovative therapeutic approaches

Non-alcoholic fatty liver disease (NAFLD) represents the most common chronic liver disease in industrialized countries. NAFLD progresses through the inflammatory phase of non-alcoholic steatohepatitis (NASH) to fibrosis and cirrhosis, with some cases developing liver failure or hepatocellular carcinoma (HCC). Liver biopsy remains the gold standard approach to a definitive diagnosis of NAFLD and the distinction between simple steatosis and NASH. The pathogenesis of NASH is still not clear. Several theories have been proposed ranging from the "Two Hit Theory" to the "Multiple Hit Theory". However, the general consensus is that the gut microbiota, oxidative stress, and mitochondrial damage play key roles in the pathogenesis of NASH. The interaction between the gut epithelia and some commensal bacteria induces the rapid generation of reactive oxygen species (ROS). The main goal of any therapy addressing NASH is to reverse or prevent progression to liver fibrosis/cirrhosis. This problem represents the first "Achilles' heel" of the new molecules being evaluated in most ongoing clinical trials. The second is the inability of these molecules to reach the mitochondria, the primary sites of energy production and ROS generation. Recently, a variety of non-pharmacological and pharmacological treatment approaches for NASH have been evaluated including vitamin E, the thiazolidinediones, and novel molecules related to NASH pathogenesis (including obeticholic acid and elafibranor). Recently, a new isoform of human manganese superoxide dismutase (MnSOD) was isolated and obtained in a synthetic recombinant form designated rMnSOD. This protein has been shown to be a powerful antioxidant capable of mediating ROS dismutation, penetrating biological barriers via its uncleaved leader peptide, and reducing portal hypertension and fibrosis in rats affected by liver cirrhosis. Based on these distinctive characteristics, it can be hypothesized that this novel recombinant protein (rMnSOD) potentially represents a new and highly efficient adjuvant therapy to counteract the progression from NASH to HCC.

Gender-Specific Association of Leptin and Adiponectin Genes With Multiple Sclerosis

BACKGROUND

Adipocytokines such as leptin (LEP) and adiponectin (ADIPOQ) represent a link between metabolism, nutritional status and immune responses. The present study aimed to determine the possible association between single nucleotide polymorphisms of LEP and ADIPOQ genes with multiple sclerosis (MS).

MATERIALS AND METHODS

Single nucleotide polymorphisms in LEP (rs2167270 or 19G > A and rs7799039 or -2,548G > A) and ADIPOQ (rs1501299 or +276G > T and rs266729 or -11,377C > G) were genotyped in 305 patients and 255 healthy individuals using polymerase chain reaction-restriction fragment length polymorphism. Sera levels of leptin and adiponectin were measured using enzyme-linked immunosorbent assay.

RESULTS

The frequencies of low leptin producer rs2167270GG genotype and rs2167270G allele were significantly lower in patients with MS compared to those of controls (for GG genotype: 39.7% and 49.8%, respectively; P = 0.01; for G allele: 63.3% and 68.8%, respectively; P = 0.05). Both polymorphisms in ADIPOQ did not show any significant association with disease susceptibility, though after gender categorization the frequency of high adiponectin producer rs1501299TT genotype and rs1501299T allele were significantly higher in male controls compared to male patients (TT genotype: P = 0.006; T allele: P = 0.006). Additionally, rs1501299TT genotype in ADIPOQ was associated with susceptibility to primary progressive multiple sclerosis (PP-MS) (P = 0.02). Moreover, while the sera levels of leptin were only different between male patients and controls (P = 0.05), adiponectin levels were significantly higher in total and female healthy controls (P < 0.001, P = 0.002, respectively).

CONCLUSIONS

Our findings provide evidence to support the hypothesis that functional ADIPOQ and LEP gene polymorphisms are associated with susceptibility to MS and its clinical forms.

Polysaccharide isolated from Aloe vera gel suppresses ovalbumin-induced food allergy through inhibition of Th2 immunity in mice

An allergic reaction occurs when the immune system overreacts to harmless substance called allergen that gains access to the body. Food allergy is a hypersensitive immune reaction to food proteins and the number of patients with food allergy has recently increased. Aloe Vera is used for wellness and medicinal purposes. In particular, Aloe vera has been reported to enhance immunity. However, the effect of Aloe vera on food allergy is not yet known. In this study, we investigated the effects of processed Aloe vera gel (PAG) containing low molecular weight Aloe polysaccharide (AP) on ovalbumin (OVA)-induced food allergy in mice. Allergic symptoms, rectal temperature, and diarrhea were measured in OVA-induced food allergy mice. Other allergic parameters were also analyzed by RT-PCR, ELISA, flow cytometry, and other biochemical methods. As the results, PAG suppressed the decrease of body temperature, diarrhea, and allergic symptoms in OVA-induced food allergy mice. PAG also reduced serum concentrations of type 2 helper T cell (Th2) cytokines (Interleukin-(IL)-4, IL-5, and IL-13) as well as histamine, mast cell protease-1 (MCP-1), and immunoglobulin (Ig)E. PAG blocked the degranulation of mast cells and infiltration of eosinophils in intestine. Furthermore, PAG suppressed the population of Th2 cells in spleen and mesenteric lymph nodes. PAG also increased the production of IL-10 and population of type 1 regulatory T (Tr1) cells in mice with food allergy. Taken together, our findings suggest that PAG suppressed Th2 immune responses through, at least partially, stimulating the secretion of IL-10 in food allergy mice.

Improved Glucose Tolerance in a Kidney Transplant Recipient With Type 2 Diabetes Mellitus After Switching From Tacrolimus To Belatacept: A Case Report and Review of Potential Mechanisms

Supplemental digital content is available in the text.

The introduction of immunosuppressant belatacept, an inhibitor of the CD28-80/86 pathway, has improved 1-year outcomes in kidney transplant recipients with preexistent diabetes mellitus and has also reduced the risk of posttransplant diabetes mellitus. So far, no studies have compared a tacrolimus-based with a belatacept-based immunosuppressive regimen with regard to improving glucose tolerance after kidney transplantation. Here, we present the case of a 54-year-old man with type 2 diabetes mellitus who was converted from belatacept to tacrolimus 1 year after a successful kidney transplantation. Thereafter, he quickly developed severe hyperglycemia, and administration of insulin was needed to improve metabolic control. Six months after this episode, he was converted back to belatacept because of nausea, diarrhea, and hyperglycemia. After switching back to belatacept and within 4 days after stopping tacrolimus glucose tolerance improved and insulin therapy could be discontinued. Although belatacept is considered less diabetogenic than tacrolimus, the rapid improvement of glucose tolerance after switching to belatacept is remarkable. In this article, the potential mechanisms of this observation are discussed.

Maternal obesity increases insulin resistance, low-grade inflammation and osteochondrosis lesions in foals and yearlings until 18 months of age

INTRODUCTION

Obesity is a growing concern in horses. The effects of maternal obesity on maternal metabolism and low-grade inflammation during pregnancy, as well as offspring growth, metabolism, low-grade inflammation, testicular maturation and osteochondrotic lesions until 18 months of age were investigated.

MATERIAL AND METHODS

Twenty-four mares were used and separated into two groups at insemination according to body condition score (BCS): Normal (N, n = 10, BCS ≤4) and Obese (O, n = 14, BCS ≥4.25). BCS and plasma glucose, insulin, triglyceride, urea, non-esterified fatty acid, serum amyloid A (SAA), leptin and adiponectin concentrations were monitored throughout gestation. At 300 days of gestation, a Frequently Sampled Intravenous Glucose Tolerance Test (FSIGT) was performed. After parturition, foals' weight and size were monitored until 18 months of age with plasma SAA, leptin, adiponectin, triiodothyronine (T3), thyroxine (T4) and cortisol concentrations measured at regular intervals. At 6, 12 and 18 months of age, FSIGT and osteoarticular examinations were performed. Males were gelded at one year and expression of genes involved in testicular maturation analysed by RT-qPCR.

RESULTS

Throughout the experiment, maternal BCS was higher in O versus N mares. During gestation, plasma urea and adiponectin were decreased and SAA and leptin increased in O versus N mares. O mares were also more insulin resistant than N mares with a higher glucose effectiveness. Postnatally, there was no difference in offspring growth between groups. Nevertheless, plasma SAA concentrations were increased in O versus N foals until 6 months, with O foals being consistently more insulin resistant with a higher glucose effectiveness. At 12 months of age, O foals were significantly more affected by osteochondrosis than N foals. All other parameters were not different between groups.

CONCLUSION

In conclusion, maternal obesity altered metabolism and increased low-grade inflammation in both dams and foals. The risk of developing osteochondrosis at 12 months of age was also higher in foals born to obese dams.

Serum Adiponectin Levels, Neuroimaging, and Cognition in the Mayo Clinic Study of Aging

BACKGROUND

Adiponectin, a protein involved in inflammatory pathways, may impact the development and progression of Alzheimer's disease (AD). Adiponectin levels have been associated with mild cognitive impairment (MCI) and AD; however, its association with Alzheimer-associated neuroimaging and cognitive outcomes is unknown.

OBJECTIVE

Determine the cross-sectional association between plasma adiponectin and neuroimaging and cognitive outcomes in an older population-based sample.

METHODS

Multivariable adjusted regression models were used to investigate the association between plasma adiponectin and hippocampal volume (HVa), PiB-PET, FDG PET, cortical thickness, MCI diagnosis, and neuropsychological test performance. Analyses included 535 non-demented participants aged 70 and older enrolled in the Mayo Clinic Study of Aging.

RESULTS

Women had higher adiponectin than men (12,631 ng/mL versus 8,908 ng/mL, p < 0.001). Among women, higher adiponectin was associated with smaller HVa (B = -0.595; 95% CI -1.19, -0.005), poorer performance in language (B = -0.676; 95% CI -1.23, -0.121), and global cognition (B = -0.459; 95% CI -0.915, -0.002), and greater odds of a MCI diagnosis (OR = 6.23; 95% CI 1.20, 32.43). In analyses stratified by sex and elevated amyloid (PiB-PET SUVR >1.4), among women with elevated amyloid, higher adiponectin was associated with smaller HVa (B = -0.723; 95% CI -1.43, -0.014), poorer performance in memory (B = -1.02; 95% CI -1.73, -0.312), language (B = -0.896; 95% CI -1.58, -0.212), global cognition (B = -0.650; 95% CI -1.18, -0.116), and greater odds of MCI (OR = 19.34; 95% CI 2.72, 137.34).

CONCLUSION

Higher plasma adiponectin was associated with neuroimaging and cognitive outcomes among women. Longitudinal analyses are necessary to determine whether higher adiponectin predicts neurodegeneration and cognitive decline.

Drugs Involved in Dyslipidemia and Obesity Treatment: Focus on Adipose Tissue

Metabolic syndrome can be defined as a state of disturbed metabolic homeostasis characterized by visceral obesity, atherogenic dyslipidemia, arterial hypertension, and insulin resistance. The growing prevalence of metabolic syndrome will certainly contribute to the burden of cardiovascular disease. Obesity and dyslipidemia are main features of metabolic syndrome, and both can present with adipose tissue dysfunction, involved in the pathogenic mechanisms underlying this syndrome. We revised the effects, and underlying mechanisms, of the current approved drugs for dyslipidemia and obesity (fibrates, statins, niacin, resins, ezetimibe, and orlistat; sibutramine; and diethylpropion, phentermine/topiramate, bupropion and naltrexone, and liraglutide) on adipose tissue. Specifically, we explored how these drugs can modulate the complex pathways involved in metabolism, inflammation, atherogenesis, insulin sensitivity, and adipogenesis. The clinical outcomes of adipose tissue modulation by these drugs, as well as differences of major importance for clinical practice between drugs of the same class, were identified. Whether solutions to these issues will be found in further adjustments and combinations between drugs already in use or necessarily in new advances in pharmacology is not known. To better understand the effect of drugs used in dyslipidemia and obesity on adipose tissue not only is challenging for physicians but could also be the next step to tackle cardiovascular disease.

Integrated Immunomodulatory Mechanisms through which Long-Chain n-3 Polyunsaturated Fatty Acids Attenuate Obese Adipose Tissue Dysfunction

Obesity is a global health concern with rising prevalence that increases the risk of developing other chronic diseases. A causal link connecting overnutrition, the development of obesity and obesity-associated co-morbidities is visceral adipose tissue (AT) dysfunction, characterized by changes in the cellularity of various immune cell populations, altered production of inflammatory adipokines that sustain a chronic state of low-grade inflammation and, ultimately, dysregulated AT metabolic function. Therefore, dietary intervention strategies aimed to halt the progression of obese AT dysfunction through any of the aforementioned processes represent an important active area of research. In this connection, fish oil-derived dietary long-chain n-3 polyunsaturated fatty acids (PUFA) in the form of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been demonstrated to attenuate obese AT dysfunction through multiple mechanisms, ultimately affecting AT immune cellularity and function, adipokine production, and metabolic signaling pathways, all of which will be discussed herein.

Effect of Mycobacterium tuberculosis infection on adipocyte physiology

Tuberculosis (TB) remains as a major threat to human health worldwide despite of the availability of standardized antibiotic therapy. One of the characteristic of pathogenic Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis is its ability to persist in the host in a dormant state and develop latent infection without clinical signs of active disease. However, the mechanisms involved in bacterial persistence and the establishment of latency is not well understood. Adipose tissue is emerging as an important niche that favors actively replicating as well as dormant Mtb during acute and latent infection. This also suggests that Mtb can disseminate from the lungs to adipose tissue during aerosol infection and/or from adipose tissue to lungs during reactivation of latent infection. In this study, we report the interplay between key adipokine levels and the dynamics of Mtb pathogenesis in the lungs and adipose tissue using a rabbit model of pulmonary infection with two clinical isolates that produce divergent outcome in disease progression. Results show that markers of adipocyte physiology and function were significantly altered during Mtb infection and distinct patterns of adipokine expression were noted between adipose tissue and the lungs. Moreover, these markers were differentially expressed between active disease and latent infection. Thus, this study highlights the importance of targeting adipocyte function as potential target for developing better TB intervention strategies.

Decreased plasma adiponectin among male firefighters with symptoms of post-traumatic stress disorder

BACKGROUND

Recent studies have reported that adiponectin-mediated neuromolecular pathways are involved in fear extinction, implying that adiponectin may be an important biological marker for posttraumatic stress disorder (PTSD). However, no study has investigated the association between adiponectin and patients with PTSD.

METHODS

We examined plasma adiponectin levels, high-sensitivity C-reactive protein (hs-CRP), and psychopathological factors using the Korean version of the Impact Event Scale-Revised (IES-R-K) and the Center for Epidemiologic Studies Depression Scale in 507 male firefighters. The PTSD symptom group was defined as those with a score of 25 or higher on the IES-R-K. Multiple logistic regression analysis was conducted to examine the covariates for the PTSD symptom group.

RESULTS

Out of 507 male firefighters, 139 (27.4%) had a score of 25 or more on the IES-R-K. The PTSD symptom group had lower plasma adiponectin levels than the controls. There was an inverse correlation between plasma adiponectin levels and PTSD severity. There was no correlation between adiponectin levels and depression. The adiponectin level was associated with the presence of PTSD symptom (odds ratio = 0.955, 95% CI = 0.920-0.991).

LIMITATIONS

A cross-sectional design and using self-rated instruments.

CONCLUSIONS

To the best of our knowledge, the results showed that decreased adiponectin-mediated activity is associated with PTSD. Future studies are necessary to identify the causative role of adiponectin for PTSD as well as any possible covariates.

Effectiveness of exercise-induced cytokines in alleviating arthritis symptoms in arthritis model mice

Recently, health awareness in Japan has been increasing and active exercise is now recommended to prevent lifestyle-related diseases. Cytokine activities have many positive effects in maintaining the health of a number of organs in the body. Myokines are cytokines secreted by skeletal muscles in response to exercise stimulation, and have recently generated much attention. Around 700,000 patients in Japan suffer from rheumatoid arthritis, making it the most prevalent autoimmune disease that requires active prevention and treatment. In the present study, a mouse model of spontaneous arthritis (SKG/Jcl) was subjected to continuous exercise stimulation, starting before the disease onset, to examine the effects of anti-inflammatory and inflammatory cytokine secretion on arthritis. For this stimulation, we developed a device that combines shaking and vibration. The results revealed that exercise stimulation delayed the onset of arthritis and slowed its progression. Thickened articular cartilage and multiple aggregates of chondrocytes were also observed. Further, exercise stimulation increased the expression of IL-6, IL-10, and IL-15, and inhibited TNF-α expression. From these results, we infer that the anti-inflammatory effects of IL-6 and IL-10, which showed increased expression upon exercise stimulation, inhibited the inflammatory activity of TNF-α and possibly delayed the onset of arthritis and slowed its progression. Novel methods for preventing and treating arthritis under clinical settings can be developed on the basis of these findings.

Serum levels of adiponectin and leptin as biomarkers of proteinuria in lupus nephritis

INTRODUCTION

There are controversial results about the role of serum leptin and adiponectin levels as biomarkers of the severity of proteinuria in lupus nephritis.

OBJECTIVE

The aim of this study was to evaluate the relationship between serum leptin and adiponectin levels with severity of proteinuria secondary to lupus nephritis (LN).

METHODS

In a cross-sectional study, 103 women with systemic lupus erythematosus (SLE) were evaluated for kidney involvement. We compared 30 SLE patients with LN, all of them with proteinuria, versus 73 SLE patients without renal involvement (no LN). A comprehensive set of clinical and laboratory variables was assessed, including serum levels of leptin and adiponectin by ELISA. Multivariate analyses were used to adjust for potential confounders associated with proteinuria in LN.

RESULTS

We found higher adiponectin levels in the LN group compared with the no LN group (20.4 ± 10.3 vs 15.6 ± 7.8 μg/mL; p = 0.02), whereas no differences were observed in leptin levels (33.3 ± 31.4 vs 22.5 ± 25.5 ng/mL; p = 0.07). Severity of proteinuria correlated with an increase in adiponectin levels (r = 0.31; p = 0.001), but no correlation was observed with leptin. Adiponectin levels were not related to anti-dsDNA or anti-nucleosome antibodies. In the logistic regression, adiponectin levels were associated with a high risk of proteinuria in SLE (OR = 1.06; 95% CI 1.01-1.12; p = 0.02). Instead, leptin was not associated with LN.

CONCLUSION

These findings indicate that adiponectin levels are useful markers associated with proteinuria in LN. Further longitudinal studies are required to identify if these levels are predictive of renal relapse.

Adaptive Immunity and Metabolic Health: Harmony Becomes Dissonant in Obesity and Aging

Adipose tissue (AT) is the primary energy reservoir organ, and thereby plays a critical role in energy homeostasis and regulation of metabolism. AT expands in response to chronic overnutrition or aging and becomes a major source of inflammation that has marked influence on systemic metabolism. The chronic, sterile inflammation that occurs in the AT during the development of obesity or in aging contributes to onset of devastating diseases such as insulin resistance, diabetes, and cardiovascular pathologies. Numerous studies have shown that inflammation in the visceral AT of humans and animals is a critical trigger for the development of metabolic syndrome. This work underscores the well-supported conclusion that the inflammatory immune response and metabolic pathways in the AT are tightly interwoven by multiple layers of relatively conserved mechanisms. During the development of diet-induced obesity or age-associated adiposity, cells of the innate and the adaptive immune systems infiltrate and proliferate in the AT. Macrophages, which dominate AT-associated immune cells in mouse models of obesity, but are less dominant in obese people, have been studied extensively. However, cells of the adaptive immune system, including T cells and B cells, contribute significantly to AT inflammation, perhaps more in humans than in mice. Lymphocytes regulate recruitment of innate immune cells into AT, and produce cytokines that influence the helpful-to-harmful inflammatory balance that, in turn, regulates organismal metabolism. This review describes inflammation, or more precisely, metabolic inflammation (metaflammation) with an eye toward the AT and the roles lymphocytes play in regulation of systemic metabolism during obesity and aging. © 2017 American Physiological Society. Compr Physiol 7:1307-1337, 2017.

Decreasing CB1 receptor signaling in Kupffer cells improves insulin sensitivity in obese mice

Objective

Obesity-induced accumulation of ectopic fat in the liver is thought to contribute to the development of insulin resistance, and increased activity of hepatic CB₁R has been shown to promote both processes. However, lipid accumulation in liver can be experimentally dissociated from insulin resistance under certain conditions, suggesting the involvement of additional mechanisms. Obesity is also associated with pro-inflammatory changes which, in turn, can promote insulin resistance. Kupffer cells (KCs), the liver's resident macrophages, are the major source of pro-inflammatory cytokines in the liver, such as TNF-α, which has been shown to inhibit insulin signaling in multiple cell types, including hepatocytes. Here, we sought to identify the role of CB₁R in KCs in obesity-induced hepatic insulin resistance.

Methods

We used intravenously administered β-D-glucan-encapsulated siRNA to knock-down CB₁R gene expression selectively in KCs.

Results

We demonstrate that a robust knock-down of the expression of Cnr1, the gene encoding CB₁R, results in improved glucose tolerance and insulin sensitivity in diet-induced obese mice, without affecting hepatic lipid content or body weight. Moreover, Cnr1 knock-down in KCs was associated with a shift from pro-inflammatory M1 to anti-inflammatory M2 cytokine profile and improved insulin signaling as reflected by increased insulin-induced Akt phosphorylation.

Conclusion

These findings suggest that CB₁R expressed in KCs plays a critical role in obesity-related hepatic insulin resistance via a pro-inflammatory mechanism.

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CB₁R signaling promotes hepatic insulin resistance by promoting hepatic steatosis and hepatic inflammation.

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CB₁R knock-down in liver macrophages (Kupffer cells, KCs) improves global insulin resistance and glucose homeostasis.

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CB₁R expressed in KCs play a critical role in hepatic insulin resistance independent of ectopic fat in the liver or adipose tissue inflammation.

Adipokines and Non-Alcoholic Fatty Liver Disease: Multiple Interactions

Accumulating evidence links obesity with low-grade inflammation which may originate from adipose tissue that secretes a plethora of pro- and anti-inflammatory cytokines termed adipokines. Adiponectin and leptin have evolved as crucial signals in many obesity-related pathologies including non-alcoholic fatty liver disease (NAFLD). Whereas adiponectin deficiency might be critically involved in the pro-inflammatory state associated with obesity and related disorders, overproduction of leptin, a rather pro-inflammatory mediator, is considered of equal relevance. An imbalanced adipokine profile in obesity consecutively contributes to metabolic inflammation in NAFLD, which is associated with a substantial risk for developing hepatocellular carcinoma (HCC) also in the non-cirrhotic stage of disease. Both adiponectin and leptin have been related to liver tumorigenesis especially in preclinical models. This review covers recent advances in our understanding of some adipokines in NAFLD and associated HCC.

Immunometabolism of human autoimmune diseases: from metabolites to extracellular vesicles

Immunometabolism focuses on the mechanisms regulating the impact of metabolism on lymphocyte activity and autoimmunity outbreak. The adipose tissue is long known to release adipokines, either pro- or anti-inflammatory factors bridging nutrition and immune function. More recently, adipocytes were discovered to also release extracellular vesicles (EVs) containing a plethora of biological molecules, including metabolites and microRNAs, which can regulate cell function/metabolism in distant tissues, suggesting that immune regulatory function by the adipose tissue may be far more complex than originally thought. Moreover, EVs were also identified as important mediators of immune cell-to-cell communication, adding a further microenvironmental mechanism of plasticity to fine-tune specific lymphocyte responses. This Review will first focus on the known mechanisms by which metabolism impacts immune function, presenting a systemic (nutrition and long-ranged adipokines) and a cellular point of view (metabolic pathway derangement in autoimmunity). It will then discuss the new discoveries concerning how EVs may act as nanometric vehicles integrating immune/metabolic responses at the level of the extracellular environment and affecting pathological processes.

Activation of Adiponectin Receptor Regulates Proprotein Convertase Subtilisin/Kexin Type 9 Expression and Inhibits Lesions in ApoE-Deficient Mice

Objective—

The reduced adiponectin levels are associated with atherosclerosis. Adiponectin exerts its functions by activating adiponectin receptor (AdipoR). Proprotein convertase subtilisin kexin type 9 (PCSK9) degrades LDLR protein (low-density lipoprotein receptor) to increase serum LDL-cholesterol levels. PCSK9 expression can be regulated by PPARγ (peroxisome proliferator–activated receptor γ) or SREBP2 (sterol regulatory element-binding protein 2). The effects of AdipoR agonists on PCSK9 and LDLR expression, serum lipid profiles, and atherosclerosis remain unknown.

Approach and Results—

At cellular levels, AdipoR agonists (ADP355 and AdipoRon) induced PCSK9 transcription/expression that solely depended on activation of PPAR-responsive element in the PCSK9 promoter. AdipoR agonists induced PPARγ expression; thus, the AdipoR agonist-activated PCSK9 expression/production was impaired in PPARγ deficient hepatocytes. Meanwhile, AdipoR agonists transcriptionally activated LDLR expression by activating SRE in the LDLR promoter. Moreover, AMP-activated protein kinase α (AMPKα) was involved in AdipoR agonist-activated PCSK9 expression. In wild-type mice, ADP355 increased PCSK9 and LDLR expression and serum PCSK9 levels, which was associated with activation of PPARγ, AMPKα and SREBP2 and reduction of LDL-cholesterol levels. In contrast, ADP355 reduced PCSK9 expression/secretion in apoE-deficient (apoE −/− ) mice, but it still activated hepatic LDLR, PPARγ, AMPKα, and SREBP2. More importantly, ADP355 inhibited lesions in en face aortas and sinus lesions in aortic root in apoE −/− mice with amelioration of lipid profiles.

Conclusions—

Our study demonstrates that AdipoR activation by agonists regulated PCSK9 expression differently in wild-type and apoE −/− mice. However, ADP355 activated hepatic LDLR expression and ameliorated lipid metabolism in both types of mice and inhibited atherosclerosis in apoE −/− mice.

Adiponectin and pro-inflammatory cytokines are modulated in Vietnamese patients with type 2 diabetes mellitus

AIMS/INTRODUCTION

Adipose tissue-derived hormones are associated with metabolic disorders including type 2 diabetes mellitus. The present study investigated the levels of adiponectin and pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β) and IL-10 in Vietnamese patients with type 2 diabetes mellitus, and their correlations with clinical parameters of overweight and type 2 diabetes mellitus.

MATERIALS AND METHODS

Based on body mass index, 73 patients with type 2 diabetes mellitus were categorized either as overweight or non-overweight. As healthy controls, 57 overweight and non-overweight individuals without type 2 diabetes mellitus were included. The adiponectin, TNF-α, IL-1β and IL-10 levels were measured in the sera samples in all study participants by enzyme-linked immunosorbent assay and were correlated with clinical parameters.

RESULTS

The adiponectin levels were lower in patients with type 2 diabetes mellitus (2.5 ± 1.5 μg/mL) compared with controls (16 ± 18.6 μg/mL; P < 0.0001), and were decreased in overweight individuals compared with those who were not overweight. The TNF-α and IL-1β levels were increased, whereas the IL-10 levels were decreased in patients with type 2 diabetes mellitus and in overweight controls compared with non-overweight controls (P < 0.0001). The adiponectin levels were correlated with the TNF-α, IL-1β, IL-10 levels, and the clinical parameters of overweight and type 2 diabetes mellitus. The quantitative insulin sensitivity check index and homeostasis model assessment insulin resistance indexes were correlated with the relative ratios of adiponectin/TNF-α, adiponectin/IL-1β, adiponectin/IL-10, TNF-α/IL-10 and IL-1β/IL-10.

CONCLUSIONS

Adiponectin and pro-inflammatory cytokines are associated with type 2 diabetes mellitus, and might serve as a prognostic marker and a therapeutic intervention for overweight-related type 2 diabetes mellitus.

Dissecting the role of AMP-activated protein kinase in human diseases

AMP-activated protein kinase (AMPK), known as a sensor and a master of cellular energy balance, integrates various regulatory signals including anabolic and catabolic metabolic processes. Accompanying the application of genetic methods and a plethora of AMPK agonists, rapid progress has identified AMPK as an attractive therapeutic target for several human diseases, such as cancer, type 2 diabetes, atherosclerosis, myocardial ischemia/reperfusion injury and neurodegenerative disease. The role of AMPK in metabolic and energetic modulation both at the intracellular and whole body levels has been reviewed elsewhere. In the present review, we summarize and update the paradoxical role of AMPK implicated in the diseases mentioned above and put forward the challenge encountered. Thus it will be expected to provide important clues for exploring rational methods of intervention in human diseases.

Lymphocytes and macrophages in adipose tissue in obesity: markers or makers of subclinical inflammation?

Obesity is accompanied by the development of chronic low-grade inflammation in adipose tissue. The presence of chronic inflammatory response along with metabolically harmful factors released by adipose tissue into the circulation is associated with several metabolic complications of obesity such as type 2 diabetes mellitus or accelerated atherosclerosis. The present review is focused on macrophages and lymphocytes and their possible role in low-grade inflammation in fat. Both macrophages and lymphocytes respond to obesity-induced adipocyte hypertrophy by their migration into adipose tissue. After activation and differentiation, they contribute to the development of local inflammatory response and modulation of endocrine function of adipose tissue. Despite intensive research, the exact role of lymphocytes and macrophages within adipose tissue is only partially clarified and various data obtained by different approaches bring ambiguous information with respect to their polarization and cytokine production. Compared to immunocompetent cells, the role of adipocytes in the obesity-related adipose tissue inflammation is often underestimated despite their abundant production of factors with immunomodulatory actions such as cytokines or adipokines such as leptin, adiponektin, and others. In summary, conflicting evidence together with only partial correlation of in vitro findings with true in vivo situation due to great heterogeneity and molecular complexity of tissue environment calls for intensive research in this rapidly evolving and important area.

Role of spleen-derived IL-10 in prevention of systemic low-grade inflammation by obesity [Review]

Obesity can be associated with systemic low-grade inflammation that leads to obesity-related metabolic disorders. Recent studies raise the possibility that the inflammation in hypothalamus, liver and white adipose tissue (WAT) contributes to the pathogenesis of diet-induced obesity. We focus on the role of interleukin (IL)-10, an anti-inflammatory cytokine produced from spleen in obesity because it is indicated that obesity decreases the expression of pro-inflammatory cytokines in spleen. Obesity results in decrease of IL-10 synthesis from spleen, probably due to reduction of B-cells expression by promoting oxidative stress and apoptosis in spleen. Splenectomy (SPX) aggravates the inflammatory response in hypothalamus, liver and WAT. These SPX-induced alterations are inhibited by systemic administration of IL-10. Moreover, in IL-10 deficiency, SPX had little effect on the inflammatory responses in these multiple organs. We show the role of spleen-derived IL-10 on inflammatory responses in obesity.

Altered levels of blood proteins in Alzheimer's disease longitudinal study: Results from Australian Imaging Biomarkers Lifestyle Study of Ageing cohort

INTRODUCTION

A blood-based biomarker panel to identify individuals with preclinical Alzheimer's disease (AD) would be an inexpensive and accessible first step for routine testing.

METHODS

We analyzed 14 biomarkers that have previously been linked to AD in the Australian Imaging Biomarkers lifestyle longitudinal study of aging cohort.

RESULTS

Levels of apolipoprotein J (apoJ) were higher in AD individuals compared with healthy controls at baseline and 18 months (P = .0003) and chemokine-309 (I-309) were increased in AD patients compared to mild cognitive impaired individuals over 36 months (P = .0008).

DISCUSSION

These data suggest that apoJ may have potential in the context of use (COU) of AD diagnostics, I-309 may be specifically useful in the COU of identifying individuals at greatest risk for progressing toward AD. This work takes an initial step toward identifying blood biomarkers with potential use in the diagnosis and prognosis of AD and should be validated across other prospective cohorts.

Intracerebroventricular administration of adiponectin attenuates streptozotocin-induced memory impairment in rats

Alzheimer’s disease (AD) has been reported to be linked with diabetes mellitus and insulin resistance. Adiponectin (ADN), an adipocytokine secreted from adipose tissue, is involved in the regulation of insulin sensitivity, energy homeostasis, and mitochondrial dysfunction. In this study, we examined the effect of ADN on passive avoidance memory in animal model of sporadic AD (sAD). On days 1 and 3 after cannulation, rats received intracerebroventricular (icv) injection of streptozotocin (STZ) (3 mg/kg). Thirty minutes before the learning process, animals received saline or ADN in different doses (6, 60, and 600 µg). The step-through latency (STL) and total time spent in the dark compartment (TDC) were recorded and analyzed. In STZ-treated rats, STL was significantly decreased, whereas TDC showed a dramatic increase. In ADN-treated rats, STL was significantly increased (P < 0.01) in all treatment doses. The number of entries was decreased in all applied doses; however, TDC was reduced only by the application of 6 ng of ADN (P < 0.05). It can be concluded that ADN is useful to improve the STZ-induced memory impairment. This study showed, for the first time, that icv administration of ADN could improve the memory acquisition in animal model of sAD.

Airway and serum adipokines after allergen and diesel exposure in a controlled human crossover study of atopic adults

Adipokines are mediators released from adipose tissue. These proteins are regarded as active elements of systemic and pulmonary inflammation, whose dysregulation can alter an individual's risk of developing allergic lung diseases. Despite this knowledge, adipokine responses to inhaled stimuli are poorly understood. We sought to measure serum and lung adiponectin, leptin, and resistin in an atopic adult study population following exposure to allergen and diesel exhaust (DE). Two types of lung samples including bronchoalveolar lavage (BAL) and bronchial wash (BW), and a time course of serum samples, were collected from the 18 subjects who participated in the randomized, double-blinded controlled human study. The two crossover exposure triads in this study were inhaled DE and filtered air each followed by instilled allergen or saline. Serum and lung adipokine responses to these exposures were quantified using enzyme-linked immunosorbent assay. Allergen significantly increased adiponectin and leptin in BAL, and adiponectin in the BW 48 hours after exposure. Serum leptin and resistin responses were not differentially affected by exposure, but varied over time. Coexposure with DE and allergen revealed significant correlations between the adiponectin/leptin ratio and FEV₁ changes and airway responsiveness measures. Changes in lung and serum adipokines in response to allergen exposure were identified in the context of a controlled exposure study. Coexposure identified a potentially protective role of adiponectin in the lung. This response was not observed in those with baseline airway hyper-responsiveness, or after allergen exposure alone. The clinical relevance of this potentially adaptive adipokine pattern warrants further study.

Role of p62 in the suppression of inflammatory cytokine production by adiponectin in macrophages: Involvement of autophagy and p21/Nrf2 axis

Adiponectin possesses potent anti-inflammatory properties. p62, an adaptor protein composed of multi-functional domain, is known to play a role in controlling inflammatory responses. In the present study, we examined the role of p62 in suppressing inflammatory cytokines produced by globular adiponectin (gAcrp) and the potential underlying mechanisms in macrophages. We demonstrated that gAcrp significantly increased p62 expression. Knockdown of p62 abrogated the suppressive effects of gAcrp on LPS-stimulated TNF-α and IL-1β expression and TRAF6/p38 MAPK pathway, indicating that p62 signaling is critical for suppressing inflammatory cytokines production by gAcrp. We next examined the role of p62 in gAcrp-induced autophagy activation, because autophagy has been shown to play a pivotal role in suppressing TNF-α. Herein, we observed that gene silencing of p62 prevented gAcrp-induced increases in autophagy-related genes and autophagosome formation. In addition, we found that Nrf2 knockdown prevented gAcrp-induced p62 expression, and p21 knockdown prevented Nrf2 induction, suggesting the role of p21/Nrf2 axis in gAcrp-induced p62 expression. Taken together, these findings imply that p62 signaling plays a crucial role in suppressing inflammatory cytokine production by globular adiponectin in macrophages, at least in part, through autophagy induction. Furthermore, the p21/Nrf2 signaling cascade contributes to p62 induction by globular adiponectin.

Circadian Rhythms in Adipose Tissue Physiology

The different types of adipose tissues fulfill a wide range of biological functions-from energy storage to hormone secretion and thermogenesis-many of which show pronounced variations over the course of the day. Such 24-h rhythms in physiology and behavior are coordinated by endogenous circadian clocks found in all tissues and cells, including adipocytes. At the molecular level, these clocks are based on interlocked transcriptional-translational feedback loops comprised of a set of clock genes/proteins. Tissue-specific clock-controlled transcriptional programs translate time-of-day information into physiologically relevant signals. In adipose tissues, clock gene control has been documented for adipocyte proliferation and differentiation, lipid metabolism as well as endocrine function and other adipose oscillations are under control of systemic signals tied to endocrine, neuronal, or behavioral rhythms. Circadian rhythm disruption, for example, by night shift work or through genetic alterations, is associated with changes in adipocyte metabolism and hormone secretion. At the same time, adipose metabolic state feeds back to central and peripheral clocks, adjusting behavioral and physiological rhythms. In this overview article, we summarize our current knowledge about the crosstalk between circadian clocks and energy metabolism with a focus on adipose physiology. © 2017 American Physiological Society. Compr Physiol 7:383-427, 2017.

The Role of the Immune System in Metabolic Health and Disease

In addition to the immune system's traditional roles of conferring anti-infectious and anti-neoplastic protection, it has been recently implicated in the regulation of systemic metabolic homeostasis. This cross-talk between the immune and the metabolic systems is pivotal in promoting "metabolic health" throughout the life of an organism and plays fundamental roles in its adaptation to ever-changing environmental makeups and nutritional availability. Perturbations in this intricate immune-metabolic cross-talk contribute to the tendency to develop altered metabolic states that may culminate in metabolic disorders such as malnutrition, obesity, type 2 diabetes mellitus (T2DM), and other features of the metabolic syndrome. Regulators of immune-metabolic interactions include host genetics, nutritional status, and the intestinal microbiome. In this Perspective, we highlight current understanding of immune-metabolism interactions, illustrate differences among individuals and between populations in this respect, and point toward future avenues of research possibly enabling immune harnessing as means of personalized treatment for common metabolic disorders.

Adiponectin confers protection from acute colitis and restricts a B cell immune response

Adiponectin demonstrates beneficial effects in various metabolic diseases, including diabetes, and in bowel cancer. Recent data also suggest a protective role in colitis. However, the precise molecular mechanisms by which adiponectin and its receptors modulate colitis and the nature of the adaptive immune response in murine models are yet to be elucidated. Adiponectin knock-out mice were orally administered dextran sulfate sodium for 7 days and were compared with wild-type mice. The severity of disease was analyzed histopathologically and through cytokine profiling. HCT116 colonic epithelial cells were employed to analyze the in vitro effects of adiponectin and AdipoR1 interactions in colonic injury following dextran sulfate sodium treatment. Adiponectin knock-out mice receiving dextran sulfate sodium exhibited severe colitis, had greater inflammatory cell infiltration, and an increased presence of activated B cells compared with controls. This was accompanied by an exaggerated proinflammatory cytokine profile and increased STAT3 signaling. Adiponectin knock-out mouse colons had markedly reduced proliferation and increased epithelial apoptosis and cellular stress. In vitro, adiponectin reduced apoptotic, anti-proliferative, and stress signals and restored STAT3 signaling. Following the abrogation of AdipoR1 in vitro, these protective effects of adiponectin were abolished. In summary, adiponectin maintains intestinal homeostasis and protects against murine colitis through interactions with its receptor AdipoR1 and by modulating adaptive immunity.

The burden of obesity in asthma and COPD: Role of adiponectin

The influence of obesity on development, severity and prognosis of both asthma and COPD is attracting growing interest. The impact of obesity on the respiratory system ranges from structural modifications (decline of total lung capacity) to humoral alterations. Adipose tissue strongly contributes to the establishment of an inflammatory state being an important source of adipokines. Amongst adipokines, adiponectin is an important component of organ cross talk with adipose tissue exerting protective effects on a variety of pathophysiological processes. Adiponectin is secreted in serum where it abundantly circulates as complexes of different molecular weight. Adiponectin properties are mediated by specific receptors that are widely expressed with AdipoR1, AdipoR2, and T-cadherin being present on epithelial and endothelial pulmonary cells indicating a functional role on lung physiology. In COPD, mild to moderate obesity has been shown to have protective effects on patient's survival, while a higher mortality rate has been observed in patients with low BMI. A specific cluster of obese patients has been identified; in this group, asthma features are particularly severe and difficult to treat. Better understanding of the molecular mechanisms at the base of cross talk among different tissues and organs will lead to identification of new targets for both diagnosis and treatment of asthma and COPD.

Exercise Training Attenuates the Dysregulated Expression of Adipokines and Oxidative Stress in White Adipose Tissue

Obesity-induced inflammatory changes in white adipose tissue (WAT), which caused dysregulated expression of inflammation-related adipokines involving tumor necrosis factor-α and monocyte chemoattractant protein-1, contribute to the development of insulin resistance. Moreover, current literature reports state that WAT generates reactive oxygen species (ROS), and the enhanced production of ROS in obese WAT has been closely associated with the dysregulated expression of adipokines in WAT. Therefore, the reduction in excess WAT and oxidative stress that results from obesity is thought to be one of the important strategies in preventing and improving lifestyle-related diseases. Exercise training (TR) not only brings about a decrease in WAT mass but also attenuates obesity-induced dysregulated expression of the adipokines in WAT. Furthermore, some reports indicate that TR affects the generation of oxidative stress in WAT. This review outlines the impact of TR on the expression of inflammation-related adipokines and oxidative stress in WAT.

Riboflavin Reduces Pro-Inflammatory Activation of Adipocyte-Macrophage Co-culture. Potential Application of Vitamin B2 Enrichment for Attenuation of Insulin Resistance and Metabolic Syndrome Development

Due to the progressive increase in the incidence of obese and overweight individuals, cardiometabolic syndrome has become a worldwide pandemic in recent years. Given the immunomodulatory properties of riboflavin, the current study was performed to investigate the potency of riboflavin in reducing obesity-related inflammation, which is the main cause of insulin resistance, diabetes mellitus 2 or arteriosclerosis. We determined whether pretreatment with a low dose of riboflavin (10.4–1000 nM) affected the pro-inflammatory activity of adipocyte-macrophage co-culture (3T3 L1-RAW 264.7) following lipopolysaccharide stimulation (LPS; 100 ng/mL) which mimics obesity-related inflammation. The apoptosis of adipocytes and macrophages as well as tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), interleukin 1beta (IL-1β), monocyte chemotactic protein 1 (MCP-1), high-mobility group box 1 (HMGB1), transforming growth factor–beta 1 (TGFβ), interleukin 10 (IL-10), inducible nitric oxide synthase (iNOS), nitric oxide (NO), matrix metalloproteinase 9 (MMP-9), tissue inhibitor of metalloproteinases-1 (TIMP-1) expression and release, macrophage migration and adipokines (adiponectin and leptin) were determined. Our results indicated an efficient reduction in pro-inflammatory factors (TNFα, IL-6, MCP-1, HMGB1) upon culture with riboflavin supplementation (500–1000 nM), accompanied by elevation in anti-inflammatory adiponectin and IL-10. Moreover, macrophage migration was reduced by the attenuation of chemotactic MCP-1 release and degradation of the extracellular matrix by MMP-9. In conclusion, riboflavin effectively inhibits the pro-inflammatory activity of adipocyte and macrophage co-cultures, and therefore we can assume that its supplementation may reduce the likelihood of conditions associated with the mild inflammation linked to obesity.

Neonatal levels of adiponectin, interleukin-10 and interleukin-12 are associated with the risk of developing type 1 diabetes in childhood and adolescence: A nationwide Danish case-control study

BACKGROUND/AIM

An in-depth understanding of the early phase of type 1 diabetes (T1D) pathogenesis is important for targeting primary prevention. We examined if 14 preselected mediators of immune responses differed in neonates that later developed T1D compared to control neonates.

METHODS

The study is a case-control study with a 1:2 matching. The individuals were born between 1981 through 2002. Cases were validated using the National Patient Register and the Danish Childhood Diabetes Register. Interleukin(IL)-1β, IL-4, IL-6, IL-8, IL-10, IL-12p70, interferon gamma, tumor necrosis factor alpha, transforming growth factor beta 1 (active form), leptin, adiponectin, c-reactive protein, mannose-binding lectin and soluble triggering receptor expressed on myeloid cells-1 were measured by using a flowmetric Luminex xMAP® technology. We tested two models both including a number of possible confounders. In the first model (model 1) we also adjusted for HLA-DQB1 genotype. A total of 1930 groups of assay-matched cases and controls (4746 individuals) were included in the statistical analyses.

RESULTS

Adiponectin was negatively associated with later risk of T1D in both models (relative change (RC), model 1: 0.95, P=0.046 and model 2: 0.95, P=0.006). IL-10 and IL-12 were both positively associated with T1D risk in the model 2 (RC, 1.19, P=0.006 and 1.07, P=0.02, respectively)-these results were borderline significant in model 1, but showed the same direction as the results from model 2.

CONCLUSIONS

Our results indicate that specific immunological signatures are already present at time of birth in children developing T1D before the age of 18years.

Downregulation of AdipoR1 is Associated with increased Circulating Adiponectin Levels in Serbian Chronic Kidney Disease Patients

BACKGROUND

Since the rise in plasma adiponectin levels in chronic kidney disease (CKD) patients has not yet been elucidated, we sought to investigate if patients on hemodialysis (HD) have altered expression of adiponectin receptors in peripheral blood mononuclear cells (PBMCs) compared to healthy subjects.

METHODS

This study included 31 patients with chronic kidney disease on HD and 33 healthy subjects (CG). Circulating adiponectin levels were measured by ELISA while AdipoR1 and AdipoR2 mRNA levels in PBMCs were determined by real-time PCR.

RESULTS

Plasma adiponectin levels were significantly higher in patients compared to control group (P=0.036). After adjustment for age, BMI and creatinine, this difference became even more significant (P=0.004). In both groups adiponectin correlated with creatinine (CG: r=-0.472, P=0.006; HD: r=-0.375, P=0.038), triglycerides (CG: r=- 0.490, P=0.004; HD: r=-0.488, P=0.005), insulin (CG: r=-0.386, P=0.038; HD: r=-0.506, P=0.012) and high density lipoprotein cholesterol (HDL-C) (CG: r=-0.672, P<0.001; HD: r=-0.584, P=0.001). Significantly lower expression of PBMCs AdipoR1 mRNA was found in patients compared to CG (P=0.034), while AdipoR2 mRNA levels were similarly expressed in PBMCs in both groups.

CONCLUSIONS

Complex pathological processes in CKD cause downregulation of AdipoR1 which could ultimately influence AdipoR1 protein levels leading to a state of ≫adiponectin resistance≪.

The Effect of Onion Peel Extract on Inflammatory Mediators in Korean Overweight and Obese Women

Quercetin, found abundantly in onion peel, has been known to have antioxidant and anti-obesity effects and improves endothelial function. The purpose of this study was to evaluate the effects of a quercetin-rich onion peel extract (OPE) on the inflammatory mediators in overweight and obese women. This study was a randomized double-blind, placebo-controlled study. Thirty-seven healthy overweight and obese women were randomly assigned to two groups, and one group was given a soft capsuled OPE (100 mg quercetin/day, n = 18) and the other group a same capsuled placebo (n = 19) for 12 weeks. Fat mass was measured by bioimpendance method at baseline and after 12 weeks of intervention. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured with colorimetric assay kits. The concentrations of leptin, adiponectin, visfatin, tumor necrosis factor (TNF)-α and interleukin (IL)-4 in plasma were determined by using enzyme-linked immunosorbent assay kits. Baseline characteristics of anthropometric indicators and blood metabolic profiles were not significantly different between placebo and OPE groups. Compared with baseline value, both placebo and OPE supplementation significantly decreased the percent of body fat mass and induced plasma adiponectin levels while ALT and AST activities as well as leptin, visfatin, TNF-α, and IL-4 levels in plasma were not significantly different between two groups after 12 weeks of the supplementation. These findings suggest that 12-week supplementation of OPE do not affect modulators of systemic inflammation in overweight and obese women.

Metabolic control of immune tolerance in health and autoimmunity

The filed that links immunity and metabolism is rapidly expanding. The adipose tissue, by secreting a series of immune regulators called adipokines, represents the common mediator linking metabolic processes and immune system functions. The dysregulation of adipokine secretion, occurring in obese individuals or in conditions of malnutrition or dietary restriction, affects the activity of immune cells resulting in inflammatory autoimmune responses or increased susceptibility to infectious diseases. Alterations of cell metabolism that characterize several autoimmune diseases strongly support the idea that the immune tolerance is also regulated by metabolic pathways. The comprehension of the molecular mechanisms underlying these alterations may lead to the development of novel therapeutic strategies to control immune cell differentiation and function in conditions of autoimmunity.

Increased Ghrelin Levels and Unchanged Adipocytokine Levels in Major Depressive Disorder

OBJECTIVE

One of the hypotheses of the pathophysiology of major depressive disorder (MDD) proposes that there is a relationship between adipocytokine and ghrelin levels and depression.

METHODS

Patients with major depression with a BMI ≤25 kg/m² between the ages of 11 and 18 years (n = 30) were compared with a healthy control group (n = 30). Both groups were evaluated across a pretreatment period (MD-PT) and an improved period (MD-I). We measured serum leptin, adiponectin, resistin, and ghrelin levels and other parameters related to metabolic syndrome, such as glucose, insulin, insulin resistance (homeostasis model assessment [HOMA]), triglycerides (TG), and total cholesterol (TCHOL).

RESULTS

Leptin, adiponectin, and resistin levels did not differ across groups; however, ghrelin levels were increased in the MD-I group compared with the control and MD-PT groups (p < 0.05). HOMA levels were also higher in the MD-PT group than in the control group (p < 0.05). After treatment, there was no difference in this measurement.

CONCLUSIONS

The relationship between adipocytokines and major depression may be dependent on ghrelin levels as a result of antidepressant treatment and subsequent obesity.

Diabetic macular edema, retinopathy and age-related macular degeneration as inflammatory conditions

Diabetic macular edema (DME) and diabetic retinopathy (DR) are complications affecting about 25% of all patients with long-standing type 1 and type 2 diabetes mellitus and are a major cause of significant decrease in vision and quality of life. Age-related macular degeneration (AMD) is not uncommon, and diabetes mellitus affects the incidence and progression of AMD through altering hemodynamics, increasing oxidative stress, accumulating advanced glycation end products, etc. Recent studies suggest that DME, DR and AMD are inflammatory conditions characterized by a breakdown of the blood-retinal barrier, inflammatory processes and an increase in vascular permeability. Key factors that seem to have a dominant role in DME, DR and AMD are angiotensin II, prostaglandins and the vascular endothelial growth factor and a deficiency of anti-inflammatory bioactive lipids. The imbalance between pro- and anti-inflammatory eicosanoids and enhanced production of pro-angiogenic factors may initiate the onset and progression of DME, DR and AMD. This implies that bioactive lipids that possess anti-inflammatory actions and suppress the production of angiogenic factors could be employed in the prevention and management of DME, DR and AMD.

From Placenta to Polycystic Ovarian Syndrome: The Role of Adipokines

Adipokines are cytokines produced mainly by adipose tissue, besides many other tissues such as placenta, ovaries, peripheral-blood mononuclear cells, liver, muscle, kidney, heart, and bone marrow. Adipokines play a significant role in the metabolic syndrome and in cardiovascular diseases, have implications in regulating insulin sensitivity and inflammation, and have significant effects on growth and reproductive function. The objective of this review was to analyze the functions known today of adiponectin, leptin, resistin, and visfatin from placenta throughout childhood and adolescence. It is well known now that their serum concentrations during pregnancy and lactation have long-term effects beyond the fetus and newborn. With regard to puberty, adipokines are involved in the regulation of the relationship between nutritional status and normal physiology or disorders of puberty and altered gonadal function, as, for example, premature pubarche and polycystic ovarian syndrome (PCOS). Cytokines are involved in the maturation of oocytes and in the regular progression of puberty and pregnancy.

Non-Alcoholic Fatty Liver Disease: Cause or Effect of Metabolic Syndrome

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease throughout the world. Pathophysiological insights into this disease have recently illustrated that various factors such as insulin resistance, innate immunity, metabolic inflammation, and the microbiota are of relevance. NAFLD, metabolic syndrome (MS), and type 2 diabetes (T2D) share many pathophysiological aspects, and inflammatory processes in the adipose tissue, gut, and liver have evolved to be of exceptional importance. Most of NAFLD patients are obese and encounter a high risk of developing MS and T2D. NAFLD, however, is also highly common in subjects with MS and T2D. Furthermore, reflecting its nature of a multisystem disease, NAFLD is associated with a high prevalence and incidence of cardiovascular and chronic kidney disease. These facts require screening strategies for MS/T2D in NAFLD patients and vice versa. Thus, the question of cause or effect cannot be answered as MS and NAFLD share many pathomechanisms, and at the time of either diagnosis both frequently coexist. This is also reflected by a global prevalence rate of 25% for both NAFLD and MS. For this reason, it is crucial that physicians are aware of the 'unholy liaison' between MS, T2D, and NAFLD.

Abdominal adipose tissue in MGUS and multiple myeloma

OBJECTIVE

To determine abdominal adipose tissue parameters on PET/CT in patients with monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) that may serve as predictors of progression of MGUS to MM. We hypothesized that patients with MM had higher abdominal adiposity and higher fat metabolic activity compared to patients with MGUS.

MATERIALS AND METHODS

Our retrospective study was IRB approved and HIPAA compliant. The study group comprised 40 patients (mean age 64 ± 13 years) with MGUS and 32 patients (mean age 62 ± 10 years) with recently diagnosed MM (mean time since diagnosis of MM 3.0 ± 3.9 months) who had not undergone MM treatment. All patients underwent whole body FDG-PET/CT. Total abdominal adipose tissue (TAT), abdominal subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) cross sectional areas (CSA) (cm(2)) and metabolic activity (SUV) were assessed. Groups were compared using ANOVA. ROC curve analysis was performed to determine cutoff values for abdominal adipose tissue parameters to detect MM.

RESULTS

Patients with recently diagnosed MM had higher TAT and SAT CSA (p ≤ 0.03) and higher fat metabolic activity (p < 0.01). VAT metabolic activity showed the highest sensitivity and specificity for identifying patients with MM (area under the curve 0.95 with cutoff value of >0.34, sensitivity 90.6 %, specificity 92.5 %, p < 0.0001).

CONCLUSIONS

Patients who were recently diagnosed with MM had higher abdominal fat CSA and higher fat metabolic activity compared to patients with MGUS. These parameters may serve as novel biomarkers of progression of MGUS to MM.

Infliximab therapy restores adiponectin expression in perivascular adipose tissue and improves endothelial nitric oxide-mediated vasodilation in mice with type 1 diabetes

Increased TNFα-mediated JNK signaling in the perivascular adipose tissue (PVAT) may contribute to the pathogenesis of vascular complications in T1DM by reducing adiponectin (Ad) synthesis and therefore impairing Ad-mediated activity in the contiguous blood vessel system. We evaluated whether in vivo treatment with the TNFα blocking antibody infliximab normalized expression of Ad and Ad receptors in various fat depots, and whether this effect correlated with improved endothelial activity and vasodilator function in streptozotocin (STZ)-induced diabetic mice. STZ mice were studied at 1 and 2weeks after diabetes onset, and compared to age-matched infliximab-treated diabetic (I-STZ) and control animals (CTRL) (n=10 each group). In STZ mice, activation of pro-inflammatory JNK signaling was faster in PVAT (P<0.01) than in visceral (VAT), epididymal (EAT) and subcutaneous (SAT) adipose depots, and associated with decreased Ad synthesis and dysregulated AdipoR1/R2 levels. In parallel, activation of JNK in aortic endothelial cells and mesenteric arteries was associated with decreased expression/phosphorylation of eNOS and impaired ACh-mediated vasodilation (P<0.05 vs. CTRL). Treatment with infliximab abrogated JNK activation, ameliorated Ad protein expression, and normalized expression of both AdipoR1 and AdipoR2 in PVAT, concomitantly improving eNOS expression and vessel relaxation in mesenteric arteries from I-STZ mice (P<0.01 vs. STZ). These observations underline the early susceptibility of PVAT to activation of pro-inflammatory JNK signaling, and highlight its potential importance in early vascular changes of T1DM. Further elucidation of the role of PVAT in cardiovascular complications may allow for the design of novel therapeutic strategies directly addressing PVAT pathophysiology.

Dendritic cells and adipose tissue

Visceral adipose tissue inflammation in obesity is an established risk factor for metabolic syndrome, which can include insulin resistance, type 2 diabetes, hypertension and cardiovascular diseases. With obesity and related metabolic disorders reaching epidemic proportions globally, an understanding of the mechanisms of adipose tissue inflammation is crucial. Within the immune cell cohort, dendritic cells (DC) play a key role in balancing tolerance and immunity. Despite decades of research into the characterization of DC in lymphoid and non-lymphoid organs, their role in adipose tissue function is poorly understood. There is now an increasing interest in identification and characterization of DC in adipose tissue and understanding their function in regulating tissue metabolic homeostasis. This review provides an overview of the study of DC in adipose tissue, focusing on possible mechanisms by which DC may contribute to adipose tissue homeostasis.

Effects of isotretinoin on body mass index, serum adiponectin, leptin, and ghrelin levels in acne vulgaris patients

Introduction

Isotretinoin has been successfully used for the treatment of acne vulgaris.

Aim

To investigate the effects of isotretinoin on body mass index (BMI), to determine whether isotretinoin causes any changes in serum adiponectin, leptin, and ghrelin levels in acne vulgaris patients, and to correlate variables.

Material and methods

Thirty-two patients were included in this study. Oral isotretinoin was begun at a dose of 0.5–0.6 mg/kg and raised to 0.6–0.75 mg/kg. Pretreatment and posttreatment third-month BMI and adiponectin, leptin, and ghrelin serum levels were measured.

Results

The pre- and posttreatment BMI values were not significantly different. In addition, serum adiponectin and leptin levels were significantly increased following isotretinoin therapy while serum ghrelin levels were not different.

Conclusions

Isotretinoin may exert its anti-inflammatory activity by increasing leptin and adiponectin levels.

Weight Gain Alters Adiponectin Receptor 1 Expression on Adipose Tissue-Resident Helios+ Regulatory T Cells

Adipose tissue produces multiple mediators that modulate the immune response. Adiponectin is an adipocyte-derived cytokine that exhibits metabolic and anti-inflammatory effects. Adiponectin acts through binding to adiponectin receptor 1 and 2 (AdipoR1/AdipoR2). AdipoR1 is ubiquitously expressed, whereas AdipoR2 is restricted to skeletal muscle and liver. AdipoR1 expression has been reported on a small percentage of T cells; nevertheless, it is still unknown whether Foxp3(+) regulatory T cells (Tregs) express AdipoR1. Recently, it has been shown that Tregs accumulate in adipose tissue and that they play a potential role in modulating adipose tissue inflammation. Our aim was to evaluate AdipoR1 expression in adipose tissue-resident Tregs and to evaluate the effect of weight gain on this expression. Male C57BL/6 mice were fed with a high-fat diet for 14 weeks (to develop overweight) or 21 weeks (to develop obesity). Mice on a standard diet were used as age-matched controls. Helios expression was evaluated as a marker to discriminate thymic-derived from peripherally induced Tregs. The majority of Tregs in both adipose tissue and the spleen expressed Helios. Adipose tissue Tregs expressed higher levels of AdipoR1 than Tregs in the spleen. AdipoR1 expression on adipose tissue Helios(+) Tregs was negatively correlated with epididymal fat. Overall, we show that AdipoR1 is expressed on adipose tissue-resident Tregs, mainly Helios(+) Tregs, and that this expression is dependent on weight and fat accumulation. Because both adiponectin and Tregs play roles in anti-inflammatory mechanisms, our data propose a new mechanism through which weight gain might alter immunoregulation.