Macrophages in human visceral adipose tissue: increased accumulation in obesity and a source of resistin and visfatin

Concentrations of leptin, adiponectin, and resistin in the serum of obese cats during weight loss

We monitored changes in serum leptin, adiponectin, and resistin concentrations in obese cats during weight loss. Six naturally developed obese cats were fed low-fat, high-fiber dry food during a 9-week experimental period. Serum leptin, adiponectin, and resistin concentrations were measured at week 0, 4, 8, and 9. Body weight became significantly lower week 4 onward than that at week 0 (P<0.05 or 0.01). At week 9, serum leptin concentrations were significantly lower than those at week 0 (P<0.05). Contrarily, serum adiponectin and resistin concentrations did not significantly differ within the 9 weeks. While serum leptin levels were strongly positively correlated with body weight (r=0.923, P<0.001), serum adiponectin levels were moderately negatively correlated with it (r=−0.529, P<0.01), with serum resistin having a no correlation with body weight. Serum leptin levels might be more closely related with pathogenesis of adiposity than serum adiponectin or resistin in cats.

Exercise training prevents the perivascular adipose tissue-induced aortic dysfunction with metabolic syndrome

The aim of the study was to determine the effects of exercise training on improving the thoracic perivascular adipose tissue (tPVAT) phenotype (inflammation, oxidative stress, and proteasome function) in metabolic syndrome and its subsequent actions on aortic function.

Methods

Lean and obese (model of metabolic syndrome) Zucker rats (n=8/group) underwent 8-weeks of control conditions or treadmill exercise (70% of max speed, 1 h/day, 5 days/week). At the end of the intervention, the tPVAT was removed and conditioned media was made. The cleaned aorta was attached to a force transducer to assess endothelium-dependent and independent dilation in the presence or absence of tPVAT-conditioned media. tPVAT gene expression, inflammatory /oxidative phenotype, and proteasome function were assessed.

Results

The main findings were that Ex induced: (1) a beige-like, anti-inflammatory tPVAT phenotype; (2) a greater abundance of ^•NO in tPVAT; (3) a reduction in tPVAT oxidant production; and (4) an improved tPVAT proteasome function. Regarding aortic function, endothelium-dependent dilation was greater in exercised lean and obese groups vs. controls (p < 0.05). Lean control tPVAT improved aortic relaxation, whereas obese control tPVAT decreased aortic relaxation. In contrast, the obese Ex-tPVAT increased aortic dilation, whereas the lean Ex-tPVAT did not affect aortic dilation.

Conclusion

Overall, exercise had the most dramatic impact on the obese tPVAT reflecting a change towards an environment with less oxidant load, less inflammation and improved proteasome function. Such beneficial changes to the tPVAT micro-environment with exercise likely played a significant role in mediating the improvement in aortic function in metabolic syndrome following 8 weeks of exercise.

Association of salivary C-reactive protein with the obesity measures and markers in children

OBJECTIVE

Overweight and obesity is a pro-inflammatory state. This study aimed to examine the level of the salivary obesity markers in normal weight (NW) and overweight/obese (OW/OB) children, association with the obesity measures and the interrelations between the biomarkers.

SUBJECTS AND METHODS

Seventy-six children (40 normal weight and 36 overweight/obese) were recruited for this study. Body weight, height, and waist circumference measurement were obtained. The saliva sample was collected from all the participants. According to the Center for Disease Control and Prevention (CDC), the participants were classified into the normal weight or overweight/obese depending upon the body mass index (BMI) percentile ranking. The obesity panel of salivary markers resistin, C-C Motif Chemokine Ligand 2 (CCL2)/monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), complement factor D, and interleukin-10 (IL-10) were determined using human magnetic Luminex performance assay. The receiver operating characteristics (ROC) analysis was used to determine the area under the curve (AUC) to identify the best salivary biomarker in children. Linear regression and Pearson's correlation analyses to determine the association between the parameters.

RESULTS

The obesity biomarkers resistin, MCP-1, TNF-α, IL-6 and CRP were significantly high in overweight/obese compared to normal weight. Salivary CRP (AUC: 0.866, 95% CI: 0.780-0.952; p<0.0001) showed superiority area under ROC curves with good discriminatory power than resistin, MCP-1, TNF-α, and IL-6. BMI z-score, WC z-score, and WHtR z-score showed a significant association (p<0.0001) with CRP. The CRP significantly (p<0.0001) correlated with resistin, CCL2/MCP-1, TNF-α, IL-6, and IL-10 by linear regression and Pearson's correlation analysis.

CONCLUSION

Increased level of salivary CRP in children may be considered as a non-invasive marker for childhood obesity for detection of the risk factors for the development of metabolic dysregulation.

Circulating visfatin levels in the second and third trimester of pregnancies with gestational diabetes: a systematic review

INTRODUCTION

There are multiple published conflicting associations of the adipocytokine visfatin with gestational diabetes. In this study, we attempted to investigate this relationship via a systematic review of the published literature.

EVIDENCE ACQUISITION

Literature retrieval using PubMed, Google Scholar, Scopus and Hydi databases followed by article selection and data extraction were conducted. Relevant studies published up to June 2018 were included. In total, 29 cohorts that were published in 27 articles were analyzed. Three studies carried out in early pregnancy were excluded. A total of 2365 individuals, with 1069 gestational diabetes (GDM) cases and 1296 controls from studies describing visfatin in the second or third trimester of gestation were included.

EVIDENCE SYNTHESIS

The difference in visfatin levels between women with GDM and the controls in the second and third trimester was measured by weighted mean difference (WMD) and 95% confidence intervals (CI). Heterogeneity was inspected by using both subgroup and meta-regression analysis. Analysis was restricted to studies describing singleton pregnancies. The quality of included studies was assessed by the Newcastle-Ottawa Scale.

CONCLUSIONS

No significant difference in circulating visfatin levels in GDM during the second trimester of pregnancy (WMD -0.30 ng/mL, 95% CI: -2.06, 1.45, SE=0.895, P=0.733) was detected. Meta-analysis of the studies in the third trimester revealed a significant negative effect, that was however driven by only one study. This finding limits the meaningful interpretation of the pooled analysis. Significant heterogeneity was identified between studies, and meta-regression analysis showed that homeostatic model assessment for insulin resistance contributes significantly to heterogeneity. In conclusion, our findings suggest that peripheral blood visfatin concentration cannot be robustly associated with gestational diabetes status in the second and third trimesters of pregnancy.

On the role of macrophages in the control of adipocyte energy metabolism

The crosstalk between macrophages (MΦ) and adipocytes within white adipose tissue (WAT) influences obesity-associated insulin resistance and other associated metabolic disorders, such as atherosclerosis, hypertension and type 2 diabetes. MΦ infiltration is increased in WAT during obesity, which is linked to decreased mitochondrial content and activity. The mechanistic interplay between MΦ and mitochondrial function of adipocytes is under intense investigation, as MΦ and inflammatory pathways exhibit a pivotal role in the reprogramming of WAT metabolism in physiological responses during cold, fasting and exercise. Thus, the underlying immunometabolic pathways may offer therapeutic targets to correct obesity and metabolic disease. Here, I review the current knowledge on the quantity and the quality of human adipose tissue macrophages (ATMΦ) and their impact on the bioenergetics of human adipocytes. The effects of ATMΦ and their secreted factors on mitochondrial function of white adipocytes are discussed, including recent research on MΦ as part of an immune signaling cascade involved in the 'browning' of WAT, which is defined as the conversion from white, energy-storing adipocytes into brown, energy-dissipating adipocytes.

Novel Mechanism for Nicotinamide Phosphoribosyltransferase Inhibition of TNF-α-mediated Apoptosis in Human Lung Endothelial Cells

Nicotinamide phosphoribosyltransferase (NAMPT) exists as both intracellular NAMPT and extracellular NAMPT (eNAMPT) proteins. eNAMPT is secreted into the blood and functions as a cytokine/enzyme (cytozyme) that activates NF-κB signaling via ligation of Toll-like receptor 4 (TLR4), further serving as a biomarker for inflammatory lung disorders such as acute respiratory distress syndrome. In contrast, intracellular NAMPT is involved in nicotinamide mononucleotide synthesis and has been implicated in the regulation of cellular apoptosis, although the exact mechanisms for this regulation are poorly understood. We examined the role of NAMPT in TNF-α-induced human lung endothelial cell (EC) apoptosis and demonstrated that reduced NAMPT expression (siRNA) increases EC susceptibility to TNF-α-induced apoptosis as reflected by PARP-1 cleavage and caspase-3 activation. In contrast, overexpression of NAMPT served to reduce degrees of TNF-α-induced EC apoptosis. Inhibition of nicotinamide mononucleotide synthesis by FK866 (a selective NAMPT enzymatic inhibitor) failed to alter TNF-α-induced human lung EC apoptosis, suggesting that NAMPT-dependent NAD⁺ generation is unlikely to be involved in regulation of TNF-α-induced EC apoptosis. We next confirmed that TNF-α-induced EC apoptosis is attributable to NAMPT secretion into the EC culture media and subsequent eNAMPT ligation of TLR4 on the EC membrane surface. Silencing of NAMPT expression, direct neutralization of secreted eNAMPT by an NAMPT-specific polyclonal antibody (preventing TLR4 ligation), or direct TLR4 antagonism all served to significantly increase EC susceptibility to TNF-α-induced EC apoptosis. Together, these studies provide novel insights into NAMPT contributions to lung inflammatory events and to novel mechanisms of EC apoptosis regulation.

Macrophages of the subcutaneous and omental fatty tissue in obese patients: Immunohistochemical phenotyping of M2 subtypes in relation to type 2 diabetes

BACKGROUND AND AIMS

Macrophages are linked to the initiation of the chronic inflammation believed to underlie the changes taking place in the white fatty tissue of obese people. Both the number of macrophages, but their functional status, play an important role in the development of inflammation. Classically, macrophages are divided into two types: pro-inflammatory (M1) and anti-inflammatory (M2) types, and based on current immunological studies, further views on the functional distribution of macrophages are suggested. In this study, we evaluated the M1 and M2 macrophages ratio in obese subjects with, or without diabetes. To identify all macrophages, we used CD68 expression, while CD204 expression is typically used for the M2 macrophage.

MATERIALS AND METHODS

During bariatric surgery, carried out in obese people with and without type 2 diabetes (T2D), we obtained subcutaneous adipose tissue from the navel and omental adipose tissue. We also obtained the same tissue from people with a physiological range of BMI from a judicial autopsy. Applying immunohistochemical staining anti-CD68 and anti-CD204, we carried out a quantitative evaluation of the number of macrophages.

RESULTS

We found CD68+ and CD204+ positive macrophages in perivascular spaces and between fat cells, both isolated and in larger infiltrates. They were also present in so-called "crown-like structures" (CLS) around dying adipocytes. Quantitative analysis showed an increased number of macrophages in all obese patients compared to the control group of non-obese, individuals without T2D. The most striking observation was the macrophage increase in the visceral fatty tissue of diabetics. The number of CD68 and CD204 positive macrophages was statistically significantly smaller in patients without T2D.

CONCLUSION

We demonstrated a significantly greater number of macrophages in visceral adipose tissue, especially in patients with T2D. Our results also show a positive correlation between the presence of T2D and the total number of macrophages; a significantly greater number of macrophages were found in visceral adipose tissue, especially in patients with T2D.

Exercise training prevents high-fat diet-induced adipose tissue remodeling by promoting capillary density and macrophage polarization

AIMS

Increasing adipose tissue capillarization is beneficial to metabolic health. The present study examined the effects of continuous training (CT) and aerobic-interval training (AIT) coinciding with a high-fat diet (HFD) on capillary density, macrophage polarization in mesenteric (mAT) and subcutaneous (sAT) adipose tissue.

MAIN METHODS

48 male Wistar rats were divided into HFD and normal diet (ND) groups. After 10 weeks, each group was divided into sedentary, CT, and AIT. The animals in training groups performed 10-week matched distances of CT and AIT on a motorized treadmill (5 times/week).

KEY FINDINGS

The results showed that HFD significantly reduced the capillary density of adipose tissue (sAT: 54% vs. mAT:49%) and increased systemic insulin resistance, mean adipocyte size, crown-like structure (CLs), and M1-macrophages with no change in the total number of adipocytes in either tissue. Exercise training reversed the HFD induced adipose tissue dysfunction. Compared to CT, AIT was more effective on increasing the capillary density of sAT (170 vs. 87%) and mAT (140 vs. 100%). Likewise, AIT increased the capillary density of both tissues even in comparison to the ND sedentary group (~25%). Compared with CT as well, AIT more significantly increased the number of M2 macrophages (181 vs. 122%) and decreased CLs (60 vs. 38%) in mAT.

SIGNIFICANCE

The findings suggest that hypertrophy is a major contributor to adipose tissue expansion in obesity. Furthermore, exercise training largely demonstrated beneficial effects on adipose tissue remodeling, where AIT is more effective than CT in reducing HFD-induced adipose tissue dysfunction.

Inflammation and Oxidative Stress in an Obese State and the Protective Effects of Gallic Acid

Metabolic complications in an obese state can be aggravated by an abnormal inflammatory response and enhanced production of reactive oxygen species. Pro-inflammatory response is known to be associated with the formation of toxic reactive oxygen species and subsequent generation of oxidative stress. Indeed, adipocytes from obese individuals display an altered adipokine profile, with upregulated expression and secretion of pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-α) and interleukin (IL-6). Interestingly, natural compounds, including phenolic enriched foods are increasingly explored for their ameliorative effects against various metabolic diseases. Of interest is gallic acid, a trihydroxybenzoic acid that has progressively demonstrated robust anti-obesity capabilities in various experimental models. In addition to reducing excessive lipid storage in obese subjects, gallic acid has been shown to specifically target the adipose tissue to suppress lipogenesis, improve insulin signaling, and concomitantly combat raised pro-inflammatory response and oxidative stress. This review will revise mechanisms involved in the pathophysiological effects of inflammation and oxidative stress in an obese state. To better inform on its therapeutic potential and improvement of human health, available evidence reporting on the anti-obesity properties of gallic acid and its derivatives will be discussed, with emphases on its modulatory effect on molecular mechanisms involved in insulin signaling, inflammation and oxidative stress.

Contribution of Adipose Tissue Inflammation to the Development of Type 2 Diabetes Mellitus

The objective of this comprehensive review is to summarize and discuss the available evidence of how adipose tissue inflammation affects insulin sensitivity and glucose tolerance. Low-grade, chronic adipose tissue inflammation is characterized by infiltration of macrophages and other immune cell populations into adipose tissue, and a shift toward more proinflammatory subtypes of leukocytes. The infiltration of proinflammatory cells in adipose tissue is associated with an increased production of key chemokines such as C-C motif chemokine ligand 2, proinflammatory cytokines including tumor necrosis factor α and interleukins 1β and 6 as well as reduced expression of the key insulin-sensitizing adipokine, adiponectin. In both rodent models and humans, adipose tissue inflammation is consistently associated with excess fat mass and insulin resistance. In humans, associations with insulin resistance are stronger and more consistent for inflammation in visceral as opposed to subcutaneous fat. Further, genetic alterations in mouse models of obesity that reduce adipose tissue inflammation are-almost without exception-associated with improved insulin sensitivity. However, a dissociation between adipose tissue inflammation and insulin resistance can be observed in very few rodent models of obesity as well as in humans following bariatric surgery- or low-calorie-diet-induced weight loss, illustrating that the etiology of insulin resistance is multifactorial. Taken together, adipose tissue inflammation is a key factor in the development of insulin resistance and type 2 diabetes in obesity, along with other factors that likely include inflammation and fat accumulation in other metabolically active tissues. © 2019 American Physiological Society. Compr Physiol 9:1-58, 2019.

NAD Metabolism in Cancer Therapeutics

Cancer cells have a unique energy metabolism for sustaining rapid proliferation. The preference for anaerobic glycolysis under normal oxygen conditions is a unique trait of cancer metabolism and is designated as the Warburg effect. Enhanced glycolysis also supports the generation of nucleotides, amino acids, lipids, and folic acid as the building blocks for cancer cell division. Nicotinamide adenine dinucleotide (NAD) is a co-enzyme that mediates redox reactions in a number of metabolic pathways, including glycolysis. Increased NAD levels enhance glycolysis and fuel cancer cells. In fact, nicotinamide phosphoribosyltransferase (Nampt), a rate-limiting enzyme for NAD synthesis in mammalian cells, is frequently amplified in several cancer cells. In addition, Nampt-specific inhibitors significantly deplete NAD levels and subsequently suppress cancer cell proliferation through inhibition of energy production pathways, such as glycolysis, tricarboxylic acid (TCA) cycle, and oxidative phosphorylation. NAD also serves as a substrate for poly(ADP-ribose) polymerase (PARP), sirtuin, and NAD gylycohydrolase (CD38 and CD157); thus, NAD regulates DNA repair, gene expression, and stress response through these enzymes. Thus, NAD metabolism is implicated in cancer pathogenesis beyond energy metabolism and considered a promising therapeutic target for cancer treatment. In this review, we present recent findings with respect to NAD metabolism and cancer pathogenesis. We also discuss the current and future perspectives regarding the therapeutics that target NAD metabolic pathways.

Expression of Three Adipokines (Adiponectin, Leptin and Resistin) in Normal Canine Skin: a Pilot Study

Adipokines are biologically active cytokines that are mainly produced in adipose tissue. There is evidence, in man and mice, that some adipokines may be secreted in other tissues including the vascular endothelium, epithelia and sebaceous glands. Moreover, modified serum levels of adipokines have been detected in people with acne vulgaris or psoriasis; it is suspected that adipokines could contribute to local and systemic inflammatory conditions. We aimed to evaluate the expression of three adipokines (i.e. leptin, adiponectin and resistin) in normal canine skin. Formalin-fixed, paraffin wax-embedded punch biopsy samples were obtained from the sparsely-haired skin of the caudal ventral abdomen of a single clinically healthy dog with no history of skin disease. Immunohistochemistry was applied, using rabbit polyclonal primary antibodies specific for leptin, adiponectin and resistin. Adipokines were not expressed in normal canine dermis or hypodermis. In contrast, they were detected in the keratinocytes of all epidermal layers and hair follicle segments, sebocytes, apocrine gland cells and in the vascular endothelium. This is the first report on the expression of adipokines in normal canine skin, a first step in studying their role in the skin physiology and inflammatory skin diseases of dogs.

Adipocytokines in Rheumatoid Arthritis: The Hidden Link between Inflammation and Cardiometabolic Comorbidities

Rheumatoid arthritis is a chronic autoimmune disease affecting typically synovial joints and leading to progressive articular damage, disability, and reduced quality of life. Despite better recent therapeutic strategies improving long-term outcomes, RA is associated with a high rate of comorbidities, infections, malignancies, and cardiovascular disease (CVD). Remarkably, some well-known pathogenic proinflammatory mediators in RA, such as interleukin-1β (IL-1β) and tumor necrosis factor (TNF), may play a pivotal role in the development of CVD. Interestingly, different preclinical and clinical studies have suggested that biologic agents commonly used to treat RA patients may be effective in improving CVD. In this context, the contribution of adipocytokines has been suggested. Adipocytokines are pleiotropic molecules, mainly released by white adipose tissue and immune cells. Adipocytokines modulate the function of different tissues and cells, and in addition to energy homeostasis and metabolism, amplify inflammation, immune response, and tissue damage. Adipocytokines may contribute to the proinflammatory state in RA patients and development of bone damage. Furthermore, they could be associated with the occurrence of CVD. In this study, we reviewed available evidence about adipocytokines in RA, because of their involvement in disease activity, associated CVD, and possible biomarkers of prognosis and treatment outcome and because of their potential as a possible new therapeutic target.

Obesity modulates the association between sleep apnea treatment and CHI3L1 levels but not CHIT1 activity in moderate to severe OSA: an observational study

Purpose

The inflammatory markers chitinase-3-like protein 1 (CHI3L1) and chitotriosidase (CHIT1) have both been associated with cardiovascular complications. The aim of this preliminary observational study was to assess the roles and interaction of obstructive sleep apnea (OSA) severity and body mass index (BMI) with plasma CHI3L1 levels and CHIT1 activity in patients with moderate to severe OSA. The second aim was to assess the roles and interaction of positive airway pressure (PAP) treatment and BMI on the expression of the same proteins.

Methods

The study included 97 OSA patients with an apnea–hypopnea index (AHI) ≥ 15 and full usage of PAP treatment after 4 months. Plasma CHI3L1 levels and CHIT1 activity were measured before and after treatment.

Results

Multiple linear regression analysis demonstrated an independent association of BMI on CHI3L1 levels (p < 0.05) but not on CHIT1 activity. The OSA severity markers (AHI and oxygen desaturation index) did not independently or in interaction with BMI levels associate with CHI3L1 levels or with CHIT1 activity (p > 0.05). A two-way repeated measures ANOVA revealed a significant interaction between PAP treatment effect (before vs. after) and BMI groups (< 35 kg/m² vs. ≥ 35 kg/m²) on CHI3L1 levels (p = 0.03) but not on CHIT1 activity (p = 0.98).

Conclusions

Obesity independently associated with CHI3L1 levels. Association between OSA severity and CHI3L1 levels or CHIT1 activity (independent of or dependent on obesity level) could not be confirmed. However, decrease was observed in CHI3L1 levels after PAP treatment in severely obese OSA patients but not in those less obese.

Electronic supplementary material

The online version of this article (10.1007/s11325-018-1731-6) contains supplementary material, which is available to authorized users.

Association between resistin and fibroblast growth factor 23 in patients with type 2 diabetes mellitus

Fibroblast growth factor 23 (FGF23) is associated with cardiovascular disease and all-cause mortality in patients with diabetes mellitus. Insulin resistance has recently been reported to increase FGF23 levels, and resistin is a peptide that mainly regulates insulin resistance. However, few studies have investigated the association between FGF23 and resistin. A total of 422 patients with diabetes mellitus were recruited for this cross-sectional study to examine the association between resistin and intact FGF23. The mean ( ± standard deviation) age was 63.1 ± 11.9 years, and the median HbA1c was 6.7% (range, 6.1-7.1%). The mean estimated glomerular filtration rate (eGFR) was 66.2 ± 23.1 mL/min/m2. Multiple regression analysis for resistin showed that logFGF23 (coefficient (Coef): 1.551; standard error (SE): 0.739; P = 0.036), C-peptide (Coef: 0.798; SE: 0.229; P = 0.001), ghrelin (Coef: 1.061; SE: 0.332; P = 0.001), intact parathyroid hormone (Coef: 0.022; SE: 0.099; P = 0.030), and eGFR (Coef: -0.091; SE: 0.017; P < 0.001) were all significantly associated with the resistin level. These associations were modified in patients with higher age, lower body mass index, and higher vitamin D levels. These results suggest that resistin is positively associated with serum FGF23 levels.

NAMPT: A pleiotropic modulator of monocytes and macrophages

Nicotinamide phosphoribosyltransferase (NAMPT) is the bottleneck enzyme of the NAD salvage pathway and thereby is a controller of intracellular NAD concentrations. It has been long known that the same enzyme can be secreted by a number of cell types and acts as a cytokine, although its receptor is at present unknown. Investigational compounds have been developed that target the enzymatic activity as well as the extracellular action (i.e. neutralizing antibodies). The present contribution reviews the evidence that links intracellular and extracellular NAMPT to myeloid biology, for example governing monocyte/macrophage differentiation, polarization and migration. Furthermore, it reviews the evidence that links this protein to some disorders in which myeloid cells have a prominent role (acute infarct, inflammatory bowel disease, acute lung injury and rheumatoid arthritis) and the data showing that inhibition of the enzymatic activity or the neutralization of the cytokine is beneficial in preclinical animal models.

Neurogenic obesity and systemic inflammation following spinal cord injury: A review

CONTENT

Spinal Cord Injury (SCI) results in physiological changes that markedly reduces whole-body metabolism, resulting in neurogenic obesity via adipose tissue accumulation. Adipose tissue has been implicated in the release of proinflammatory adipokines that lead to chronic, systemic inflammation, and evidence suggests these adipokines contribute to the pathogeneses of metabolic diseases that often accompany obesity. In this review, we propose the concept of neurogenic obesity through paralysis-induced adiposity as the primary source of systemic inflammation and metabolic dysfunction reported in chronic SCI. We also briefly discuss how exercise in SCI can attenuate the negative consequences of obesity-induced inflammation and its comorbidities.

METHODS

A MEDLINE, PubMed, Google Scholar, and ClinicalKey search was performed using the following search terms: obesity, adiposity, adipose tissue, proinflammatory adipokines, proinflammatory cytokines, metabolic dysfunction, exercise, physical activity, and spinal cord injury. All papers identified were full-text, English language papers. The reference list of identified papers was also searched for additional papers.

RESULTS

Research suggests that obesity in SCI results in a state of chronic, systemic inflammation primarily through proinflammatory adipokines secreted from excess adipose tissue. The reduction of adipose tissue through the use of diet and exercise demonstrates promise to combat neurogenic obesity, inflammation, and cardiometabolic dysfunction in SCI.

CONCLUSION

Proinflammatory adipokines may serve as biomarkers for the development of obesity-related complication in SCI. Mechanistic and interventional studies on neurogenic obesity-induced inflammation in chronic SCI are warranted.

M1/M2 macrophage polarization in human obese adipose tissue

Obesity and insulin resistance are closely associated with chronic inflammation in adipose tissue, where macrophages play an important role. Adipose tissue macrophages can be divided into two main phenotypes: the classical M1 macrophages and alternatively activated macrophages M2. M1 macrophages produce pro-inflammatory cytokines (TNF-α, interleukin IL-6 and MCP-1) and thus contribute to the development of insulin resistance. On the other hand, M2 macrophages, anti-inflammatory, are involved in the maintenance of tissue homeostasis and are typical in the adipose tissue of slender individuals. Macrophages can also play a role in the pathogenesis of other serious illnesses such as cardiovascular diseases or cancer. This article reviews the latest data on macrophage polarization in adipose tissue.

Blood-based novel biomarkers for nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease has become a social health challenge of global concern. The term nonalcoholic steatohepatitis (NASH) is a more severe condition than simple steatosis and distinguishing NASH from nonalcoholic fatty liver disease is particularly important. Liver biopsy remains a gold standard in diagnosing NASH. Meanwhile, radiological techniques such as ultrasonography and MRI are also applied widely. However, the invasive and expensive examination is not suitable for screening, and there is a great need for reliable and appropriate biomarkers to screen patients for NASH. Based on the current studies of blood-based novel biomarkers, we attempt to summarize the latest findings on biomarkers for NASH, including blood biomarkers encompassing proteins, lipids and miRNAs; the correlation between extracellular vesicles and NASH; and treatment strategies for NASH.

Exercise training alters the genomic response to acute exercise in human adipose tissue

Aim:

To determine the genomic mechanisms by which adipose tissue responds to acute and chronic exercise.

Methods:

We profiled the transcriptomic and epigenetic response to acute exercise in human adipose tissue collected before and after endurance training.

Results:

Although acute exercises were performed at same relative intensities, the magnitude of transcriptomic changes after acute exercise was reduced by endurance training. DNA methylation remodeling induced by acute exercise was more prominent in trained versus untrained state. We found an overlap between gene expression and DNA methylation changes after acute exercise for 32 genes pre-training and six post-training, notably at adipocyte-specific genes.

Conclusion:

Training status differentially affects the epigenetic and transcriptomic response to acute exercise in human adipose tissue.

Obese asthmatics are characterized by altered adipose tissue macrophage activation

BACKGROUND

Adipose tissue-derived inflammation is linked to obesity-related comorbidities. This study aimed to quantify and immuno-phenotype adipose tissue macrophages (ATMs) from obese asthmatics and obese non-asthmatics and to examine associations between adipose tissue, systemic and airway inflammation.

METHODS

Visceral (VAT) adipose tissue and subcutaneous (SAT) adipose tissue were collected from obese adults undergoing bariatric surgery and processed to obtain the stromovascular fraction. Pro-inflammatory (M1) and anti-inflammatory (M2) macrophages were quantified by flow cytometry. Cytospins of induced sputum were stained for differential cell counts. Plasma C-reactive protein (CRP) and CD163 were measured by ELISA.

RESULTS

VAT contained a higher number of ATMs compared to SAT. A higher percentage of M1 ATMs was observed in VAT of obese asthmatics compared to obese non-asthmatics. The M1:M2 ratio in VAT was negatively associated with FEV₁ %. Sputum macrophage count was correlated positively with M1 ATMs and negatively with M2 ATMs in VAT. In obese asthmatics, CRP was positively associated with M1:M2 ratio in VAT. There were no associations with CD163. An elevated ratio of M1:M2 ATMs was observed in VAT of obese asthmatics with increased disease severity.

CONCLUSIONS AND CLINICAL RELEVANCE

Visceral inflammation with increased pro-inflammatory macrophages (M1) occurs in obese asthma and may be a determinant of systemic inflammation and asthma severity.

Obesity associated disease risk: the role of inherent differences and location of adipose depots

Obesity and associated metabolic co-morbidities are a worldwide public health problem. Negative health outcomes associated with obesity, however, do not arise from excessive adiposity alone. Rather, deleterious outcomes of adipose tissue accumulation are a result of how adipocytes are distributed to individual regions in the body. Due to our increased understanding of the dynamic relationship that exists between specific adipose depots and disease risk, an accurate characterization of total body adiposity as well as location is required to properly evaluate a population's disease risk. Specifically, distinctive tissue depots within the body include the lower body, upper body and abdominal (deep and superficial) subcutaneous regions, as well as visceral (mesenteric and omental) regions. Upper body and visceral adipose tissues are highly associated with metabolic dysfunction and chronic disease development, whereas lower body gluteofemoral subcutaneous adipose tissue imparts protection against diet-induced metabolic derangement. Each adipose depot functions distinctly as an endocrine organ hence it has a different level of impact on health outcomes. Effluent from adipose tissue can modulate the functions of other tissues, whilst receiving differential communication from the rest of the body via central nervous system innervation, metabolites and other signaling molecules. More so, adipose depots contain a diverse reservoir of tissue-resident immune cells that play an integral part in both maintaining tissue homeostasis, as well as propagating metabolically-induced inflammation. Overall, the conceptualization of obesity and associated risks needs updating to reflect the complexities of obesity. We review adipose tissue characteristics that are linked to deleterious or beneficial adipose tissue distributions.

Targeting IκappaB kinases for cancer therapy

The inhibitory kappa B kinases (IKKs) and IKK related kinases are crucial regulators of the pro-inflammatory transcription factor, nuclear factor kappa B (NF-κB). The dysregulation in the activities of these kinases has been reported in several cancer types. These kinases are known to regulate survival, proliferation, invasion, angiogenesis, and metastasis of cancer cells. Thus, IKK and IKK related kinases have emerged as an attractive target for the development of cancer therapeutics. Several IKK inhibitors have been developed, few of which have advanced to the clinic. These inhibitors target IKK either directly or indirectly by modulating the activities of other signaling molecules. Some inhibitors suppress IKK activity by disrupting the protein-protein interaction in the IKK complex. The inhibition of IKK has also been shown to enhance the efficacy of conventional chemotherapeutic agents. Because IKK and NF-κB are the key components of innate immunity, suppressing IKK is associated with the risk of immune suppression. Furthermore, IKK inhibitors may hit other signaling molecules and thus may produce off-target effects. Recent studies suggest that multiple cytoplasmic and nuclear proteins distinct from NF-κB and inhibitory κB are also substrates of IKK. In this review, we discuss the utility of IKK inhibitors for cancer therapy. The limitations associated with the intervention of IKK are also discussed.

Parallels in Immunometabolic Adipose Tissue Dysfunction with Ageing and Obesity

Ageing, like obesity, is often associated with alterations in metabolic and inflammatory processes resulting in morbidity from diseases characterised by poor metabolic control, insulin insensitivity, and inflammation. Ageing populations also exhibit a decline in immune competence referred to as immunosenescence, which contributes to, or might be driven by chronic, low-grade inflammation termed "inflammageing". In recent years, animal and human studies have started to uncover a role for immune cells within the stromal fraction of adipose tissue in driving the health complications that come with obesity, but relatively little work has been conducted in the context of immunometabolic adipose function in ageing. It is now clear that aberrant immune function within adipose tissue in obesity-including an accumulation of pro-inflammatory immune cell populations-plays a major role in the development of systemic chronic, low-grade inflammation, and limiting the function of adipocytes leading to an impaired fat handling capacity. As a consequence, these changes increase the chance of multiorgan dysfunction and disease onset. Considering the important role of the immune system in obesity-associated metabolic and inflammatory diseases, it is critically important to further understand the interplay between immunological processes and adipose tissue function, establishing whether this interaction contributes to age-associated immunometabolic dysfunction and inflammation. Therefore, the aim of this article is to summarise how the interaction between adipose tissue and the immune system changes with ageing, likely contributing to the age-associated increase in inflammatory activity and loss of metabolic control. To understand the potential mechanisms involved, parallels will be drawn to the current knowledge derived from investigations in obesity. We also highlight gaps in research and propose potential future directions based on the current evidence.

Serum visfatin levels in non-obese women with polycystic ovary syndrome and matched controls

Objective

The purpose of the current study was to compare the circulating levels of visfatin between women with polycystic ovary syndrome (PCOS) and those without PCOS and to assess the correlations between visfatin levels and various parameters.

Methods

This case-control study recruited 74 PCOS patients and 74 age- and body mass index (BMI)-matched controls. Serum visfatin levels were evaluated using the enzyme-linked immunosorbent assay. Women with PCOS were divided into 2 subgroups based on the presence of clinical or biochemical hyperandrogenism. The possible differences in serum visfatin levels between the hyperandrogenic and non-hyperandrogenic groups were also assessed.

Results

Visfatin levels in PCOS patients were similar to those in the controls. However, hyperandrogenic patients had significantly higher mean serum visfatin levels than those in non-hyperandrogenic patients (3.87 ng/mL; 95% confidence intervals [CIs], 3.09–4.85 in hyperandrogenic group vs. 2.69 ng/mL; 95% CIs, 2.06–3.52 in non-hyperandrogenic group; P=0.038). In women with PCOS, visfatin levels positively correlated with BMI (r=0.23; P=0.047) and the log free androgen index (FAI) (r=0.27; P=0.021) and negatively correlated with high-density lipoprotein (HDL) cholesterol levels (r=−0.37; P=0.025). Except for HDL cholesterol levels, these correlations were also observed in controls.

Conclusion

Visfatin levels in PCOS patients were similar to those in the controls. However, hyperandrogenic patients showed significantly higher serum visfatin levels than those of non-hyperandrogenic patients, and visfatin had a positive linear correlation with FAI in both PCOS patients and controls.

Biomechanics, obesity, and osteoarthritis. The role of adipokines: When the levee breaks

Osteoarthritis is a high-incidence painful and debilitating disease characterized by progressive degeneration of articular joints, which indicates a breakdown in joint homeostasis favoring catabolic processes. Biomechanical loading, associated with inflammatory and metabolic imbalances of joint, strongly contributes to the initiation and progression of the disease. Obesity is a primary risk factor for disease onset, and mechanical factors increased the risk for disease progression. Moreover, inflammatory mediators, in particular, adipose tissue-derived cytokines (better known as adipokines) play a critical role linking obesity and osteoarthritis. The present article summarizes the knowledge about the role of adipokines in cartilage and bone function, highlighting their contribution to the imbalance of joint homeostasis and, consequently, pathogenesis of osteoarthritis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:594-604, 2018.

Adipocytokines and ghrelin level of bipolar patients from manic episode to euthymic episode

PURPOSE

Obesity and metabolic syndrome (MeS) are more frequently observed in bipolar patients than the general population. This may result from the differences of adipocytokines and ghrelin levels in bipolar disorder.

MATERIAL AND METHODS

We evaluated the leptin, adiponectin, resistin and ghrelin levels in bipolar patients (n = 30) in manic episode and in a control group (n = 30). After treatment, the same patients were evaluated again during the euthymic episode. We also measured the insulin, glucose, insulin resistance (HOMA), trygliceride (TG), total cholesterol (TCHOL), high density lipoprotein cholesterol (HDL) and low density lipoprotein cholesterol (LDL) in relation to the (MeS).

RESULTS

When controlling for age, BMI and glucose, leptin levels were higher in the bipolar disorder manic episode group (BD-ME) and bipolar euthymic episode group (BD-EE) than the control group; resistin levels were higher in the BD-ME compared to the control group and it had a positive correlation with Young Mania Rating Scale (YMRS). After treatment, ghrelin levels were higher in the BD-EE compared to the BD-ME group. There was no difference among the groups with respect to adiponectin.

CONCLUSIONS

The present results point that high leptin, resistin and ghrelin levels may be involved in the early pathophysiological process which can lead to later obesity and MeS in patients with bipolar disorder.

A Review of the Biological Activities of Microalgal Carotenoids and Their Potential Use in Healthcare and Cosmetic Industries

Carotenoids are natural pigments that play pivotal roles in many physiological functions. The characteristics of carotenoids, their effects on health, and the cosmetic benefits of their usage have been under investigation for a long time; however, most reviews on this subject focus on carotenoids obtained from several microalgae, vegetables, fruits, and higher plants. Recently, microalgae have received much attention due to their abilities in producing novel bioactive metabolites, including a wide range of different carotenoids that can provide for health and cosmetic benefits. The main objectives of this review are to provide an updated view of recent work on the health and cosmetic benefits associated with carotenoid use, as well as to provide a list of microalgae that produce different types of carotenoids. This review could provide new insights to researchers on the potential role of carotenoids in improving human health.

Plasminogen Activator Inhibitor-1 Level Correlates with Lipoprotein Subfractions in Obese Nondiabetic Subjects

BACKGROUND

The elevated level of plasminogen activator inhibitor-1 (PAI-1) in obese subjects with metabolic syndrome and in patients with type 2 diabetes is well established. The association of plasma PAI-1 and lipid metabolism is still unclear. The aim of the present study was to determine the relationship between plasma PAI-1 levels and the distribution of lipoprotein subfractions in obese and lean nondiabetic individuals.

SUBJECTS AND METHODS

We enrolled fifty nondiabetic obese patients and thirty-two healthy volunteers. Lipoprotein subfractions were detected with Lipoprint System. Plasma PAI-1, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and myeloperoxidase (MPO) concentrations were determined with enzyme-linked immunosorbent assay (ELISA), while serum paraoxonase-1 (PON1) activities were measured by spectrophotometry.

RESULTS

The TNF-α, IL-6, oxidized low-density lipoprotein (oxLDL), and MPO levels were found to be significantly higher, while PON1 paraoxonase and arylesterase activities were nonsignificantly lower in the obese patients. Strong significant negative correlations were found between plasma PAI-1 concentration and mean LDL size, as well as between PAI-1 concentrations and the levels of the large and intermediate high-density lipoprotein (HDL) subfractions. In multiple regression analysis, PAI-1 was predicted by waist circumference and intermediate HDL subfraction.

CONCLUSION

The significant correlations between PAI-1 levels and lipoprotein subfractions indicate the link between PAI-1 and lipid metabolism in obesity.

Bidirectional Association Between Psoriasis and Obesity: Benefits and Risks

Psoriasis is a chronic, immune-mediated inflammatory skin disease that is associated with several comorbidities such as obesity. This study was designed to estimate the possibility of utilizing psoriasin, nestin, keratin-16 (Krt16), and interleukin-21 (IL-21) as biochemical markers of psoriasis, to correlate these candidate psoriatic markers with biomarkers of obesity [body mass index (BMI), leptin, and resistin], and to elucidate the bidirectional association between obesity and psoriasis. Blood samples were collected from all participants (n = 108) who were classified according to their BMI into 4 groups: healthy control, obese, psoriatic, and obese psoriatic group. Plasma psoriasin, nestin, Krt16, IL-21, leptin, and resistin were estimated for all subjects. Psoriasin, nestin, Krt16, IL-21, leptin, and resistin were significantly elevated in psoriatic and obese psoriatic groups. However, only leptin, resistin, IL-21, and Krt16 were significantly increased in the obese group compared with the control group. Leptin and resistin showed significant positive correlations with psoriasis area and severity index score, psoriasin, nestin, Krt16, and IL-21. Cutoff values for psoriasin, nestin, Krt16, and IL-21 were 187.5 ng/mL, 1825 pg/mL, 33.1 ng/mL, and 128.6 ng/L, respectively. In conclusion, psoriasin, nestin, Krt16, and IL-21 can be utilized as biochemical markers of psoriasis; these psoriatic markers are significantly positively correlated with obesity biomarkers, and obesity can be considered a risk factor and/or consequence of psoriasis.

Contribution of Adipose Tissue to Development of Cancer

Solid tumor growth and metastasis require the interaction of tumor cells with the surrounding tissue, leading to a view of tumors as tissue-level phenomena rather than exclusively cell-intrinsic anomalies. Due to the ubiquitous nature of adipose tissue, many types of solid tumors grow in proximate or direct contact with adipocytes and adipose-associated stromal and vascular components, such as fibroblasts and other connective tissue cells, stem and progenitor cells, endothelial cells, innate and adaptive immune cells, and extracellular signaling and matrix components. Excess adiposity in obesity both increases risk of cancer development and negatively influences prognosis in several cancer types, in part due to interaction with adipose tissue cell populations. Herein, we review the cellular and noncellular constituents of the adipose "organ," and discuss the mechanisms by which these varied microenvironmental components contribute to tumor development, with special emphasis on obesity. Due to the prevalence of breast and prostate cancers in the United States, their close anatomical proximity to adipose tissue depots, and their complex epidemiologic associations with obesity, we particularly highlight research addressing the contribution of adipose tissue to the initiation and progression of these cancer types. Obesity dramatically modifies the adipose tissue microenvironment in numerous ways, including induction of fibrosis and angiogenesis, increased stem cell abundance, and expansion of proinflammatory immune cells. As many of these changes also resemble shifts observed within the tumor microenvironment, proximity to adipose tissue may present a hospitable environment to developing tumors, providing a critical link between adiposity and tumorigenesis. © 2018 American Physiological Society. Compr Physiol 8:237-282, 2018.

Increased mitochondrial calcium uniporter in adipocytes underlies mitochondrial alterations associated with insulin resistance

Intracellular calcium influences an array of pathways and affects cellular processes. With the rapidly progressing research investigating the molecular identity and the physiological roles of the mitochondrial calcium uniporter (MCU) complex, we now have the tools to understand the functions of mitochondrial Ca²⁺ in the regulation of pathophysiological processes. Herein, we describe the role of key MCU complex components in insulin resistance in mouse and human adipose tissue. Adipose tissue gene expression was analyzed from several models of obese and diabetic rodents and in 72 patients with obesity as well as in vitro insulin-resistant adipocytes. Genetic manipulation of MCU activity in 3T3-L1 adipocytes allowed the investigation of the role of mitochondrial calcium uptake. In insulin-resistant adipocytes, mitochondrial calcium uptake increased and several MCU components were upregulated. Similar results were observed in mouse and human visceral adipose tissue (VAT) during the progression of obesity and diabetes. Intriguingly, subcutaneous adipose tissue (SAT) was spared from overt MCU fluctuations. Furthermore, MCU expression returned to physiological levels in VAT of patients after weight loss by bariatric surgery. Genetic manipulation of mitochondrial calcium uptake in 3T3-L1 adipocytes demonstrated that changes in mitochondrial calcium concentration ([Ca²⁺]_mt) can affect mitochondrial metabolism, including oxidative enzyme activity, mitochondrial respiration, membrane potential, and reactive oxygen species formation. Finally, our data suggest a strong relationship between [Ca²⁺]_mt and the release of IL-6 and TNFα in adipocytes. Altered mitochondrial calcium flux in fat cells may play a role in obesity and diabetes and may be associated with the differential metabolic profiles of VAT and SAT.

Variability in responses observed in human white adipose tissue models

Obesity is a risk factor for a myriad of diseases including diabetes, cardiovascular dysfunction, cirrhosis, and cancer, and there is a need for new systems to study how excess adipose tissue relates to the onset of disease processes. This study provides proof-of-concept patient-specific tissue models of human white adipose tissue to accommodate the variability in human samples. Our 3D tissue engineering approach established lipolytic responses and changes in insulin-stimulated glucose uptake from small volumes of human lipoaspirate, making this methodology useful for patient specific sample source assessments of treatment strategies, drug responses, disease mechanisms, and other responses that vary between patients. Mature unilocular cells were maintained ex vivo in silk porous scaffolds for up to a month of culture and imaged non-invasively with coherent anti-Stokes Raman scattering. Interestingly, differences in responsiveness between tissues were observed in terms of magnitude of lipolysis, ability to suppress lipolysis, differences in glucose uptake, and lipid droplet size. Body mass index was not a factor in determining tissue responsiveness; rather, it is speculated that other unknown variables in the backgrounds of different patients (ethnicity, athleticism, disease history, lifestyle choices, etc.) likely had a more significant effect on the observed differences. This study reinforces the need to account for the variability in backgrounds and genetics within the human population to determine adipose tissue responsiveness. In the future, this tissue system could be used to inform individualized care strategies-enhancing therapeutic precision, improving patient outcomes, and reducing clinical costs.

Extracellular NAMPT/visfatin causes p53 deacetylation via NAD production and SIRT1 activation in breast cancer cells

Visfatin, which is secreted as an adipokine and cytokine, has been implicated in cancer development and progression. In this study, we investigated the NAD-producing ability of visfatin and its relationship with SIRT1 (silent information regulator 2) and p53 to clarify the role of visfatin in breast cancer. MCF-7 breast cancer cells were cultured and treated with visfatin. SIRT1 activity was assessed by measuring fluorescence intensity from fluoro-substrate peptide. To investigate the effect of visfatin on p53 acetylation, SDS-PAGE followed by western blotting was performed using specific antibodies against p53 and its acetylated form. Total NAD was measured both in cell lysate and the extracellular medium by colorimetric method. Visfatin increased both extracellular and intracellular NAD concentrations. It also induced proliferation of breast cancer cells, an effect that was abolished by inhibition of its enzymatic activity. Visfatin significantly increased SIRT1 activity, accompanied by induction of p53 deacetylation. In conclusion, the results show that extracellular visfatin produces NAD that causes upregulation of SIRT1 activity and p53 deacetylation. These findings explain the relationship between visfatin and breast cancer progression.

NAMPT-Mediated NAD Biosynthesis as the Internal Timing Mechanism: In NAD+ World, Time Is Running in Its Own Way

The biological age of organisms differs from the chronological age and is determined by internal aging clock(s). How cells estimate time on a scale of 24 hours is relatively well studied; however, how biological time is measured by cells, tissues, organs, or organisms in longer time periods (years and decades) is largely unknown. What is clear and widely agreed upon is that the link to age and age-related diseases is not chronological, as it does not depend on a fixed passage of time. Rather, this link depends on the biological age of an individual cell, tissue, organ, or organism and not on time in a strictly chronological sense. Biological evolution does not invent new methods as often as improving upon already existing ones. It should be easier to evolve and remodel the existing (circadian) time clock mechanism to use it for measurement or regulation of longer time periods than to invent a new time mechanism/clock. Specifically, it will be demonstrated that the circadian clock can also be used to regulate circannual or even longer time periods. Nicotinamide phosphoribosyltransferase (NAMPT)-mediated nicotinamide adenine dinucleotide (NAD+) levels, being regulated by the circadian clock, might be the missing link between aging, cell cycle control, DNA damage repair, cellular metabolism and the aging clock, which is responsible for the biological age of an organism. The hypothesis that NAMPT/NAD+/SIRT1 might represent the time regulator that determines the organismal biological age will be presented. The biological age of tissues and organs might be regulated and synchronized through eNAMPT blood secretion. The "NAD World 2.0" concept will be upgraded with detailed insights into mechanisms that regulate NAD⁺-mediated aging clock ticking, the duration and amplitude of which are responsible for the aging rate of humans.

Circulating resistin levels and risk of multiple myeloma in three prospective cohorts

BACKGROUND

Resistin is a polypeptide hormone secreted by adipose tissue. A prior hospital-based case-control study reported serum resistin levels to be inversely associated with risk of multiple myeloma (MM). To date, this association has not been investigated prospectively.

METHODS

We measured resistin concentrations for pre-diagnosis peripheral blood samples from 178 MM cases and 358 individually matched controls from three cohorts participating in the MM cohort consortium.

RESULTS

In overall analyses, higher resistin levels were weakly associated with reduced MM risk. For men, we observed a statistically significant inverse association between resistin levels and MM (odds ratio, 0.44; 95% confidence interval (CI) 0.24-0.83 and 0.54; 95% CI 0.29-0.99, for the third and fourth quartiles, respectively, vs the lowest quartile; P_trend=0.03). No association was observed for women.

CONCLUSIONS

This study provides the first prospective evidence that low circulating resistin levels may be associated with an increased risk of MM, particularly for men.

Visfatin Is Actively Secreted In Vitro From U-937 Macrophages, but Only Passively Released From 3T3-L1 Adipocytes and HepG2 Hepatocytes

Visfatin is a multi-functional molecule that can act intracellularly and extracellularly as an adipokine, cytokine and enzyme. One of the main questions concerning visfatin is the mechanism of its secretion; whether, how and from which cells visfatin is released. The objective of this in vitro study was to observe the active secretion of visfatin from 3T3-L1 preadipocytes and adipocytes, HepG2 hepatocytes, U-937, THP-1 and HL-60 monocytes and macrophages. The amount of visfatin in media and cell lysate was always related to the intracellular enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), to exclude the passive release of visfatin. Visfatin was not found in media of 3T3-L1 preadipocytes. In media of 3T3-L1 adipocytes and HepG2 hepatocytes, the ratio of visfatin to the amount of GAPDH was identical to cell lysates. Hence, it is likely that these cells do not actively secrete visfatin in a significant manner. However, we found that significant producers of visfatin are differentiated macrophages and that the amount of secreted visfatin depends on used cell line and it is affected by the mode of differentiation. Results show that 3T3-L1 adipocytes and HepG2 hepatocytes released visfatin only passively during the cell death. U-937 macrophages secrete visfatin in the greatest level from all of the tested cell lines.

Molecular Biomarkers for Weight Control in Obese Individuals Subjected to a Multiphase Dietary Intervention

CONTEXT

Although calorie restriction has proven beneficial for weight loss, long-term weight control is variable between individuals.

OBJECTIVE

To identify biomarkers of successful weight control during a dietary intervention (DI).

DESIGN, SETTING, AND PARTICIPANTS

Adipose tissue (AT) transcriptomes were compared between 21 obese individuals who either maintained weight loss or regained weight during the DI. Results were validated on 310 individuals from the same study using quantitative reverse transcription polymerase chain reaction and protein levels of potential circulating biomarkers measured by enzyme-linked immunosorbent assay.

INTERVENTION

Individuals underwent 8 weeks of low-calorie diet, then 6 months of ad libitum diet.

OUTCOME MEASURE

Weight changes at the end of the DI.

RESULTS

We evaluated six genes that had altered expression during DI, encode secreted proteins, and have not previously been implicated in weight control (EGFL6, FSTL3, CRYAB, TNMD, SPARC, IGFBP3), as well as genes for which baseline expression differed between those with good and poor weight control (ASPN, USP53). Changes in plasma concentrations of EGFL6, FSTL3, and CRYAB mirrored AT messenger RNA expression; all decreased during DI in individuals with good weight control. ASPN and USP53 had higher baseline expression in individuals who went on to have good weight control. Expression quantitative trait loci analysis found polymorphisms associated with expression levels of USP53 in AT. A regulatory network was identified in which transforming growth factor β1 (TGF-β1) was responsible for downregulation of certain genes during DI in good controllers. Interestingly, ASPN is a TGF-β1 inhibitor.

CONCLUSIONS

We found circulating biomarkers associated with weight control that could influence weight management strategies and genes that may be prognostic for successful weight control.

Growth Hormone's Effect on Adipose Tissue: Quality versus Quantity

Obesity is an excessive accumulation or expansion of adipose tissue (AT) due to an increase in either the size and/or number of its characteristic cell type, the adipocyte. As one of the most significant public health problems of our time, obesity and its associated metabolic complications have demanded that attention be given to finding effective therapeutic options aimed at reducing adiposity or the metabolic dysfunction associated with its accumulation. Growth hormone (GH) has therapeutic potential due to its potent lipolytic effect and resultant ability to reduce AT mass while preserving lean body mass. However, AT and its resident adipocytes are significantly more dynamic and elaborate than once thought and require one not to use the reduction in absolute mass as a readout of efficacy alone. Paradoxically, therapies that reduce GH action may ultimately prove to be healthier, in part because GH also possesses potent anti-insulin activities along with concerns that GH may promote the growth of certain cancers. This review will briefly summarize some of the newer complexities of AT relevant to GH action and describe the current understanding of how GH influences this tissue using data from both humans and mice. We will conclude by considering the therapeutic use of GH or GH antagonists in obesity, as well as important gaps in knowledge regarding GH and AT.

Human T cell immunosenescence and inflammation in aging

The aging process is driven by a finite number of inter-related mechanisms that ultimately lead to the emergence of characteristic phenotypes, including increased susceptibility to multiple chronic diseases, disability, and death. New assays and analytical tools have become available that start to unravel some of these mechanisms. A prevailing view is that aging leads to an imbalance between stressors and stress-buffering mechanisms that causes loss of compensatory reserve and accumulation of unrepaired damage. Central to this paradigm are changes in the immune system and the chronic low-grade proinflammatory state that affect many older individuals, even when they are apparently healthy and free of risk factors. Independent of chronological age, high circulating levels of proinflammatory markers are associated with a high risk of multiple adverse health outcomes in older persons. In this review, we discuss current theories about causes and consequences of the proinflammatory state of aging, with a focus on changes in T cell function. We examine the role of NF-κB activation and its dysregulation and how NF-κB activity differs among subgroups of T cells. We explore emerging hypotheses about immunosenescence and changes in T cell behavior with age, including consideration of the T cell antigen receptor and regulatory T cells (T_regs). We conclude by illustrating how research using advanced technology is uncovering clues at the core of inflammation and aging. Some of the preliminary work in this field is already improving our understanding of the complex mechanisms by which immunosenescence of T cells is intertwined during human aging.

Impact of Growth Hormone on Regulation of Adipose Tissue

Increasing prevalence of obesity and obesity-related conditions worldwide has necessitated a more thorough understanding of adipose tissue (AT) and expanded the scope of research in this field. AT is now understood to be far more complex and dynamic than previously thought, which has also fueled research to reevaluate how hormones, such as growth hormone (GH), alter the tissue. In this review, we will introduce properties of AT important for understanding how GH alters the tissue, such as anatomical location of depots and adipokine output. We will provide an overview of GH structure and function and define several human conditions and cognate mouse lines with extremes in GH action that have helped shape our understanding of GH and AT. A detailed discussion of the GH/AT relationship will be included that addresses adipokine production, immune cell populations, lipid metabolism, senescence, differentiation, and fibrosis, as well as brown AT and beiging of white AT. A brief overview of how GH levels are altered in an obese state, and the efficacy of GH as a therapeutic option to manage obesity will be given. As we will reveal, the effects of GH on AT are numerous, dynamic and depot-dependent. © 2017 American Physiological Society. Compr Physiol 7:819-840, 2017.

Extracellular NAMPT/Visfatin induces proliferation through ERK1/2 and AKT and inhibits apoptosis in breast cancer cells

BACKGROUND

Visfatin is a novel adipokine and proinflammatory cytokine which is implicated in breast cancer progression. The exact proliferative and anti-apoptotic mechanisms of visfatin are still under debate. In this study, the effect of extracellular visfatin on proliferation and apoptosis of breast cancer cells were investigated considering key regulatory molecules in these procedures.

METHODS

BrdU (Bromodeoxyuridine) experiment was used to assess cell proliferation in response to visfatin treatment. Cell viability and apoptosis were assessed using MTT assay and flowcytometry, respectively. Phosphorylation levels of AKT and ERK1/2 as well as survivin levels and Poly ADP ribose polymerase (PARP) cleavage were investigated by western blot analysis.

RESULTS

Visfatin induced proliferation of MCF-7 and MDA-MB-231 cells, an effect that was repressed by using AKT and ERK1/2 inhibitors, indicating involvement of these two signaling pathways in the proliferative effect of visfatin. Similarly, phosphorylation of AKT and ERK1/2 were elevated by visfatin treatment. On the other hand, visfatin improved cell viability and prevented TNF-α-induced apoptosis as well as PARP cleavage. Visfatin also exerted a protective effect on survivin.

CONCLUSION

The results of this study suggest that visfatin induces breast cancer cell proliferation through AKT/PI3K and ERK/MAPK activation and protects against apoptosis in these cells. Thus increased visfatin levels may augment breast cancer development and attenuate treatment efficiency in breast cancer patients.

Chemotherapy and plasma adipokines level in patients with colorectal cancer

Adipokines are molecules produced and secreted by adipose tissue and are linked to multiple malignancies. Adipokines can suppress or promote particular cell behaviors in different types of cancer. The aim of this study was to investigate the impact of chemotherapy on select adipokines in patients with colorectal cancer (CRC). Blood samples were collected from 42 patients with pathologically documented advanced CRC, who required palliative chemotherapy. Leptin, adiponectin, resistin and visfatin levels were measured by ELISA before and 3 months after the administration of chemotherapy. Among the 42 patients evaluated, 18 achieved a partial response (PR), 16 achieved stable disease (SD) and 8 patients experienced disease progression (PD). We found that 5-fluorouracil-based chemotherapy regimens significantly increased plasma levels of leptin and adiponectin and decreased plasma levels of resistin and visfatin in PR and SD patients, whereas the plasma levels of these molecules were not affected in PD patients. Furthermore, the mean plasma levels of leptin were significantly lower, and the mean plasma levels of resistin and visfatin were significantly greater in patients with PD compared with PR and SD both before and after chemotherapy treatment. We conclude that palliative chemotherapy in CRC patients, in addition to providing clinical benefits, positively affects cytokine production and secretion in PR and SD patients. Specifically, we found that palliative chemotherapy increased plasma levels of the anti-inflammatory adipokine adiponectin and decreased the plasma levels of visfatin and resistin, molecules known to promote angiogenesis and cancer cell proliferation in PR and SD patients. Moreover, the baseline values of leptin, visfatin and resistin might serve as prognostic indicators of a poor response to chemotherapy.

Differential expression of visfatin, leptin, stromal cell derived factor-1α, endothelial nitric oxide synthase, and vascular endothelial growth factor in human leiomyomas

AIM

This study was aimed to understand expressions of the visfatin, leptin, stromal cell derived factor (SDF)-1α, endothelial nitric oxide synthase (eNOS), and vascular endothelial growth factor (VEGF) in human uterine leiomyomas (UL) and normal myometrium.

METHOD

This study investigated expression of visfatin, leptin, SDF-1α, eNOS and VEGF in 23 uterine leiomyoma patients and 10 normal myometrium by RT-PCR and western blot. Messenger RNA transcripts of SDF-1α, eNOS, VEGF and hypoxia inducible factor-1α (HIF-1α) were analyzed according to the size of UL by real-time PCR.

RESULTS

There were no significant differences in expressions of visfatin and leptin between UL compared with normal myometrium. However, expressions of eNOS, SDF-1α and VEGF were significantly higher in both intramural and subserosal UL compared with normal myometrium. The expression of SDF1-α was significantly increased in small UL (<5 cm) compared to the large UL (≥5 cm), whereas the expressions of eNOS, VEGF and HIF-1α were higher in large UL than small UL.

CONCLUSIONS

This study shows that expression of SDF-1α, eNOS and VEGF were significantly higher in UL than myometrium with a different expression pattern according to the size of UL. However, expressions of visfatin and leptin had no significant differences between the two groups.