Fatty acid binding proteins--the evolutionary crossroads of inflammatory and metabolic responses

MicroRNA-21 modulates brown adipose tissue adipogenesis and thermogenesis in a mouse model of polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS), the most common endocrine disorder in premenopausal women, is associated with increased obesity, hyperandrogenism, and altered brown adipose tissue (BAT) thermogenesis. MicroRNAs play critical functions in brown adipocyte differentiation and maintenance. We aim to study the role of microRNA-21 (miR-21) in altered energy homeostasis and BAT thermogenesis in a PCOS mouse model of peripubertal androgen exposure.

METHODS

Three-week-old miR-21 knockout (miR21KO) or wild-type (WT) female mice were treated with dihydrotestosterone (DHT) or vehicle for 90 days. Body composition was determined by EchoMRI. Energy expenditure (EE), oxygen consumption (VO2), carbon dioxide production (VCO2), and respiratory exchange ratio (RER) were measured by indirect calorimetry. Androgen receptor (AR), and markers of adipogenesis, de novo lipogenesis, angiogenesis, extracellular matrix remodeling, and thermogenesis were quantified by RT-qPCR and/or Western-blot.

RESULTS

MiR-21 ablation attenuated DHT-mediated increase in body weight while having no effect on fat or BAT mass. MiR-21 ablation attenuated DHT-mediated BAT AR upregulation. MiR-21 ablation did not alter EE; however, miR21KO DHT-treated mice have reduced VO2, VCO2, and RER. MiR-21 ablation reversed DHT-mediated decrease in food intake and increase in sleep time. MiR-21 ablation decreased some adipogenesis (Adipoq, Pparγ, and Cebpβ) and extracellular matrix remodeling (Mmp-9 and Timp-1) markers expression in DHT-treated mice. MiR-21 ablation abolished DHT-mediated increases in thermogenesis markers Cpt1a and Cpt1b, while decreasing CIDE-A expression.

CONCLUSIONS

Our findings suggest that BAT miR-21 may play a role in regulating DHT-mediated thermogenic dysfunction in PCOS. Modulation of BAT miR-21 levels could be a novel therapeutic approach for the treatment of PCOS-associated metabolic derangements.

An evaluation of a hepatotoxicity risk induced by the microplastic polymethyl methacrylate (PMMA) using HepG2/THP-1 co-culture model

Inappropriate disposal of plastic wastes and their durability in nature cause uncontrolled accumulation of plastic in land/marine ecosystems, also causing destructive effects by bioaccumulating along the food chain. Microplastics may cause chronic inflammation in relation to their permanent structures, especially through oxidative stress and cytotoxic cellular damage, which could increase the risk of cancer development. The accumulation of microplastics in the liver is a major concern, and therefore, the identification of the mechanisms of their hepatotoxic effects is of great importance. Polymethyl methacrylate (PMMA) is a widely used thermoplastic. It has been determined that PMMA disrupts lipid metabolism in the liver in various aquatic organisms and causes reproductive and developmental toxicity. PMMA-induced hepatotoxic effects in humans have not yet been clarified. In our study, the toxic effects of PMMA (in the range of 3-10 μm) on the human liver were investigated using the HepG2/THP-1 macrophage co-culture model, which is a sensitive immune-mediated liver injury model. Cellular uptake of micro-sized PMMA in the cells was done by transmission electron microscopy. Determination of its effects on cell viability and inflammatory response, oxidative stress, along with gene and protein expression levels that play a role in the mechanism pathways underlying the effects were investigated. The results concluded that inflammation, oxidative stress, and disruptions in lipid metabolism should be the focus of attention as important underlying causes of PMMA-induced hepatotoxicity. Our study, which points out the potential adverse effects of microplastics on human health, supports the literature information on the subject.

FABP7 drives an inflammatory response in human astrocytes and is upregulated in Alzheimer's disease

Alzheimer's disease (AD), the most common cause of dementia in the elderly, is characterized by the accumulation of intracellular neurofibrillary tangles, extracellular amyloid plaques, and neuroinflammation. In partnership with microglial cells, astrocytes are key players in the regulation of neuroinflammation. Fatty acid binding protein 7 (FABP7) belongs to a family of conserved proteins that regulate lipid metabolism, energy homeostasis, and inflammation. FABP7 expression is largely restricted to astrocytes and radial glia-like cells in the adult central nervous system. We observed that treatment of primary hippocampal astrocyte cultures with amyloid β fragment 25-35 (Aβ25-35) induces FABP7 upregulation. In addition, FABP7 expression is upregulated in the brain of APP/PS1 mice, a widely used AD mouse model. Co-immunostaining with specific astrocyte markers revealed increased FABP7 expression in astrocytes. Moreover, astrocytes surrounding amyloid plaques displayed increased FABP7 staining when compared to non-plaque-associated astrocytes. A similar result was obtained in the brain of AD patients. Whole transcriptome RNA sequencing analysis of human astrocytes differentiated from induced pluripotent stem cells (i-astrocytes) overexpressing FABP7 identified 500 transcripts with at least a 2-fold change in expression. Gene Ontology enrichment analysis identified (i) positive regulation of cytokine production and (ii) inflammatory response as the top two statistically significant overrepresented biological processes. We confirmed that wild-type FABP7 overexpression induces an NF-κB-driven inflammatory response in human i-astrocytes. On the other hand, the expression of a ligand-binding impaired mutant FABP7 did not induce NF-κB activation. Together, our results suggest that the upregulation of FABP7 in astrocytes could contribute to the neuroinflammation observed in AD.

Maternal serum fatty acid binding protein-4 level is upregulated in fetal growth restriction with abnormal Doppler flow patterns

PURPOSE

This study aimed to determine fatty acid binding protein-4 (FABP-4) concentrations in maternal serum of fetal growth restriction (FGR) pregnancies and controls of normal pregnancies. Furthermore, we hypothesized that the alterations in FABP-4 levels might correlate with FGR severity.

METHODS

We performed this prospective case-control study with 83 pregnant women. The study groups included 26 FGR pregnancies without abnormal fetal Doppler flow patterns and 25 pregnancies complicated with FGR accompanied by abnormal fetal Doppler flow patterns.

RESULTS

The median serum FABP-4 concentrations were significantly higher in the FGR cases with abnormal Doppler flow pattern group (2.09 ng/mL) than in the FGR cases without abnormal Doppler flow pattern group (1.62 ng/mL) and the control group (1.20 ng/mL, p < 0.001). A significant negative correlation was observed between maternal serum FABP-4 levels and time to birth from blood sample collection (r = -0.356 and p = 0.001), gestational week at birth (r = -0.386 and p < 0.001), and birth weight (r = -0.394 and p < 0.001). A 1.35 ng/mL cut-off value of serum FABP-4 level could be used to discriminate FGR cases with a 78.4% sensitivity and 60.6% specificity. The optimal cut-off value of FABP-4 levels as an indicator for the diagnosis of FGR with abnormal Doppler flow pattern was estimated to be 1.76 ng/mL, which yielded a sensitivity of 84.0% and a specificity of 75.8%.

CONCLUSION

FABP-4 is a crucial biomarker in the diagnosis and determining the severity of pregnancies with restricted fetal growth. We consider that FABP-4 is a powerful, reliable, and unique biomarker to diagnose FGR pregnancies.

Decreased Proteasomal Function Exacerbates Endoplasmic Reticulum Stress-Induced Chronic Inflammation in Obese Adipose Tissue

Low-grade chronic inflammation contributes to both aging and the pathogenesis of age-related diseases. White adipose tissue (WAT) in obese individuals exhibits chronic inflammation, which is associated with obesity-related disorders. Aging exacerbates obesity-related inflammation in WAT; however, the molecular mechanisms underlying chronic inflammation and its exacerbation by aging remain unclear. Age-related decline in activity of the proteasome, a multisubunit proteolytic complex, has been implicated in age-related diseases. This study employed a mouse model with decreased proteasomal function that exhibits age-related phenotypes to investigate the impact of adipocyte senescence on WAT inflammation. Transgenic mice expressing proteasomal subunit β5t with weak chymotrypsin-like activity experience reduced lifespan and develop age-related phenotypes. Mice fed with a high-fat diet and experiencing proteasomal dysfunction exhibited increased WAT inflammation, increased infiltration of proinflammatory M1-like macrophages, and increased proinflammatory adipocytokine-like monocyte chemoattractant protein-1, plasminogen activator inhibitor-1, and tumor necrosis factor-α, which are all associated with activation of endoplasmic reticulum (ER) stress-related pathways. Impaired proteasomal activity also activated ER stress-related molecules and induced expression of proinflammatory adipocytokines in adipocyte-like cells differentiated from 3T3-L1 cells. Collective evidence suggests that impaired proteasomal activity increases ER stress and that subsequent inflammatory pathways play pivotal roles in WAT inflammation. Because proteasomal function declines with age, age-related proteasome impairment may be involved in obesity-related inflammation among elderly individuals.

Modulation of mitochondrial activity by sugarcane (Saccharum officinarum L.) top extract and its bioactive polyphenols: a comprehensive transcriptomics analysis in C2C12 myotubes and HepG2 hepatocytes

Age-related mitochondrial dysfunction leads to defects in cellular energy metabolism and oxidative stress defense systems, which can contribute to tissue damage and disease development. Among the key regulators responsible for mitochondrial quality control, peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) is an important target for mitochondrial dysfunction. We have previously reported that bioactive polyphenols extracted from sugarcane top (ST) ethanol extract (STEE) could activate neuronal energy metabolism and increase astrocyte PGC-1α transcript levels. However, their potential impact on the mitochondria activity in muscle and liver cells has not yet been investigated. To address this gap, our current study examined the effects of STEE and its polyphenols on cultured myotubes and hepatocytes in vitro. Rhodamine 123 assay revealed that the treatment with STEE and its polyphenols resulted in an increase in mitochondrial membrane potential in C2C12 myotubes. Furthermore, a comprehensive examination of gene expression patterns through transcriptome-wide microarray analysis indicated that STEE altered gene expressions related to mitochondrial functions, fatty acid metabolism, inflammatory cytokines, mitogen-activated protein kinase (MAPK) signaling, and cAMP signaling in both C2C12 myotubes and HepG2 hepatocytes. Additionally, protein-protein interaction analysis identified the PGC-1α interactive-transcription factors-targeted regulatory network of the genes regulated by STEE, and the quantitative polymerase chain reaction results confirmed that STEE and its polyphenols upregulated the transcript levels of PGC-1α in both C2C12 and HepG2 cells. These findings collectively suggest the potential beneficial effects of STEE on muscle and liver tissues and offer novel insights into the potential nutraceutical applications of this material.

Adipose tissue-derived FABP4 mediates glucagon-stimulated hepatic glucose production in gestational diabetes

AIMS

One of the most common complications of pregnancy is gestational diabetes mellitus (GDM), which may result in significant health threats of the mother, fetus and the newborn. Fatty acid-binding protein 4 (FABP4) is an adipokine that regulates glucose homeostasis by promoting glucose production and liver insulin resistance in mouse models. FABP4 levels are increased in GDM and correlates with maternal indices of insulin resistance, with a rapid decline post-partum. We therefore aimed to determine the tissue origin of elevated circulating FABP4 levels in GDM and to assess its potential contribution in promoting glucagon-induced hepatic glucose production.

MATERIALS AND METHODS

FABP4 protein and gene expression was determined in biopsies from placenta, subcutaneous (sWAT) and visceral (vWAT) white adipose tissues from GDM and normoglycaemic pregnant women. FABP4 differential contribution in glucagon-stimulated hepatic glucose production was tested in conditioned media before and after its immune clearance.

RESULTS

We showed that FABP4 is expressed in placenta, sWAT and vWAT of pregnant women at term, with a significant increase in its secretion from vWAT of women with GDM compared with normoglycaemic pregnant women. Neutralizing FABP4 from both normoglycaemic pregnant women and GDM vWAT secretome, resulted in a decrease in glucagon-stimulated hepatic glucose production.

CONCLUSIONS

This study provides new insights into the role of adipose tissue-derived FABP4 in GDM, highlighting this adipokine, as a potential co-activator of glucagon-stimulated hepatic glucose production during pregnancy.

Perfluorohexanesulfonic acid (PFHxS) induces oxidative stress and causes developmental toxicities in zebrafish embryos

Perfluorohexanesulfonic acid (PFHxS) is a short-chain perfluoroalkyl substance widely used to replace the banned perfluorooctanesulfonic acid (PFOS) in different industrial and household products. It has currently been identified in the environment and human bodies; nonetheless, the possible toxicities are not well-known. Zebrafish have been used as a toxicant screening model due to their fast and transparent developmental processes. In this study, zebrafish embryos were exposed to PFHxS for five days, and various experiments were performed to monitor the developmental and cellular processes. Liquid chromatography-mass spectrometry (LC/MS) analysis confirmed that PFHxS was absorbed and accumulated in the zebrafish embryos. We reported that 2.5 µM or higher PFHxS exposure induced phenotypic abnormalities, marked by developmental delay in the mid-hind brain boundary and yolk sac edema. Additionally, larvae exposed to PFHxS displayed facial malformation due to the reduction of neural crest cell expression. RNA sequencing analysis further identified 4643 differentiated expressed transcripts in 5 µM PFHxS-exposed 5-days post fertilization (5-dpf) larvae. Bioinformatics analysis revealed that glucose metabolism, lipid metabolism, as well as oxidative stress were enriched in the PFHxS-exposed larvae. To validate these findings, a series of biological experiments were conducted. PFHxS exposure led to a nearly 4-fold increase in reactive oxygen species, possibly due to hyperglycemia and impaired glutathione balance. The Oil Red O' staining and qPCR analysis strengthens the notions that lipid metabolism was disrupted, leading to lipid accumulation, lipid peroxidation, and malondialdehyde formation. All these alterations ultimately affected cell cycle events, resulting in S and G2/M cell cycle arrest. In conclusion, our study demonstrated that PFHxS could accumulate and induce various developmental toxicities in aquatic life, and such data might assist the government to accelerate the regulatory policy on PFHxS usage.

Associations of three thermogenic adipokines with metabolic syndrome in obese and non-obese populations from the China plateau: the China Multi-Ethnic Cohort

OBJECTIVES

High altitude exposure decreases the incidence of obesity and metabolic syndrome, but increases the expression of the thermogenic adipokines (leptin, fat cell fatty acid-binding protein (A-FABP) and visfatin). This study investigated the correlation of these adipokines with obesity and metabolic syndrome (MetS) in populations residing in a plateau-specific environment.

DESIGN

Case-control study.

SETTING

We cross-sectionally analysed data from the China Multi-Ethnic Cohort.

PARTICIPANTS

A total of 475 obese (OB, body mass index (BMI)≥28.0 kg/m²) plateau Han people and 475 age, sex and region-matched non-obese (NO, 18.5≤BMI<24.0 kg/m²) subjects were recruited. MetS was defined according to the National Cholesterol Education Program Adult Treatment Panel III guidelines.

PRIMARY AND SECONDARY OUTCOME MEASURES

Data with normal distributions were expressed as the mean (Stanard Deviation, SD), and data with skewed distributions were expressed as the median (Interquartile Range, IQR). The participants were grouped and the rank-sum test, χ² test or t-tests was used for comparing groups. Spearman correlation coefficients were estimated to assess the relationships among leptin, A-FABP, visfatin and the components of MetS in each group.

RESULTS

A-FABP was an independent predictor of OB (OR, 1.207; 95% CI, 1.170 to 1.245; p<0.05), ABSI (OR, 1.035; 95%CI, 1.019 to 1.052; p<0.05) and MetS (OR, 1.035; 95% CI, 1.013 to 1.057; p<0.05). Leptin was an independent predictor of MetS in the NO group. Visfatin was an independent predictor of increased ABSI, but not for OB or MetS.

CONCLUSION

An abnormally elevated plasma A-FABP level, but not leptin or visfatin is a potential risk factor for MetS in high-altitude populations.

Immune infiltration and diagnostic value of immune-related genes in periodontitis using bioinformatics analysis

BACKGROUND AND OBJECTIVES

Periodontitis, which is a chronic inflammatory periodontal disease resulting in destroyed periodontal tissue, is the leading cause of tooth loss in adults. Many studies have found that inflammatory immune responses are involved in the risk of periodontal tissue damage. Therefore, we analyzed the association between immunity and periodontitis using bioinformatics methods to further understand this disease.

MATERIALS AND METHODS

First, the expression profiles of periodontitis and healthy samples were downloaded from the GEO database, including a training dataset GSE16134 and an external validation dataset GSE10334. Then, differentially expressed genes were identified using the limma package. Subsequently, immune cell infiltration was calculated by using the CIBERSORT algorithm. We further identified genes linking periodontitis and immunity from the ImmPort and DisGeNet databases. In addition, some of them were selected to construct a diagnostic model via a logistic stepwise regression analysis.

RESULTS AND CONCLUSIONS

Two hundred sixty differentially expressed genes were identified and found to be involved in responses to bacterial and immune-related processes. Subsequently, immune cell infiltration analysis demonstrates significant differences in the abundance of most immune cells between periodontitis and healthy samples, especially in plasma cells. These results suggested that immunity doses play a non-negligible role in periodontitis. Twenty-one genes linking periodontitis and immunity were further identified. And nine hub genes of them were identified that may be key genes involved in the development of periodontitis. Gene ontology analyses showed that these genes are involved in response to molecules of bacterial origin, cell chemotaxis, and response to chemokines. In addition, three genes of them were selected to construct a diagnostic model. And its good diagnostic performance was demonstrated by the receiver operating characteristic curves, with an area under the curve of 0.9424 for the training dataset and 0.9244 for the external validation dataset.

Naturally-occurring carboxylic acids from traditional antidiabetic plants as potential pancreatic islet FABP3 inhibitors. A molecular docking-aided study

The antidiabetic action of traditional plants is mostly attributed to their antioxidant and anti-inflammatory properties. These plants are still having some secrets, making them an attractive source that allows for investigating new drugs or uncovering precise pharmacologic antidiabetic functions of their constituents. In diabetes, which is a lipid disease, long-term exposure of pancreatic islet beta cells to fatty acids (FAs) increases basal insulin release, reduces glucose-stimulated insulin secretion, causes islet beta cell inflammation, failure and apoptosis. Pancreatic islet beta cells express fatty acid binding protein 3 (FABP3) that receives long-chain FAs and traffics them throughout different cellular compartments to be metabolized and render their effects. Inhibition of this FABP3 may retard FA metabolism and protect islet beta cells. Since FAs interact with FABPs by their carboxylic group, some traditionally-known antidiabetic plants were reviewed in the present study, searching for their components that have common features of FABP ligands, namely carboxylic group and hydrophobic tail. Many of these carboxylic acids were computationally introduced into the ligand-binding pocket of FABP3 and some of them exhibited FABP3 ligand possibilities. Among others, the naturally occurring ferulic, cleomaldeic, caffeic, sinapic, hydroxycinnamic, 4-p-coumaroylquinic, quinoline-2-carboxylic, chlorogenic, 6-hydroxykynurenic, and rosmarinic acids in many plants are promising candidates for being FABP3-specific inhibitors. The study shed light on repurposing these phyto-carboxylic acids to function as FABP inhibitors. However, more in-depth biological and pharmacological studies to broaden the understanding of this function are needed.

AM-879, a PPARy non-agonist and Ser273 phosphorylation blocker, promotes insulin sensitivity without adverse effects in mice

Obesity is one of the main risk factors for type 2 diabetes, and peroxisome proliferator-activated receptor γ (PPARγ) is considered a promising pathway on insulin sensitivity and adipose tissue metabolism. The search for molecules acting as insulin sensitizers have increased, especially for molecules that block PPARγ-Ser273 phosphorylation, without reaching full agonism. We evaluated the in vivo effects of AM-879, a PPARγ non-agonist, and found that AM-879 exerts different effects in mice depending on the dose. At lower doses, this ligand decreased BAT, increased leptin and Crh expression. However, at a higher dose, it promoted improvement on insulin sensitivity, ameliorates expression of metabolism-related genes, decreased the expression of genes related to liver toxicity, maintaining body weight and adipocyte size. These results present a new lead molecule to ameliorates insulin resistance and confirm AM-879 as a PPARγ non-agonist which blocks Ser273 phosphorylation as a good strategy to modulate insulin sensitivity without developing the adverse effects promoted by PPARγ full agonists.

The Role of Fatty Acid Binding Protein 3 in Cardiovascular Diseases

Fatty acid binding proteins (FABPs) are proteins found in the cytosol that contribute to disorders related to the cardiovascular system, including atherosclerosis and metabolic syndrome. Functionally, FABPs serve as intracellular lipid chaperones, interacting with hydrophobic ligands and mediating their transportation to sites of lipid metabolism. To date, nine unique members of the FABP family (FABP 1–9) have been identified and classified according to the tissue in which they are most highly expressed. In the literature, FABP3 has been shown to be a promising clinical biomarker for coronary and peripheral artery disease. Given the rising incidence of cardiovascular disease and its associated morbidity/mortality, identifying biomarkers for early diagnosis and treatment is critical. In this review, we highlight key discoveries and recent studies on the role of FABP3 in cardiovascular disorders, with a particular focus on its clinical relevance as a biomarker for peripheral artery disease.

Gut Microbiota and Phenotypic Changes Induced by Ablation of Liver- and Intestinal-Type Fatty Acid-Binding Proteins

Intestinal fatty acid-binding protein (IFABP; FABP2) and liver fatty acid-binding protein (LFABP; FABP1) are small intracellular lipid-binding proteins. Deficiency of either of these proteins in mice leads to differential changes in intestinal lipid transport and metabolism, and to markedly divergent changes in whole-body energy homeostasis. The gut microbiota has been reported to play a pivotal role in metabolic process in the host and can be affected by host genetic factors. Here, we examined the phenotypes of wild-type (WT), LFABP^-/-, and IFABP^-/- mice before and after high-fat diet (HFD) feeding and applied 16S rRNA gene V4 sequencing to explore guild-level changes in the gut microbiota and their associations with the phenotypes. The results show that, compared with WT and IFABP^-/- mice, LFABP^-/- mice gained more weight, had longer intestinal transit time, less fecal output, and more guilds containing bacteria associated with obesity, such as members in family Desulfovibrionaceae. By contrast, IFABP^-/- mice gained the least weight, had the shortest intestinal transit time, the most fecal output, and the highest abundance of potentially beneficial guilds such as those including members from Akkermansia, Lactobacillus, and Bifidobacterium. Twelve out of the eighteen genotype-related bacterial guilds were associated with body weight. Interestingly, compared with WT mice, the levels of short-chain fatty acids in feces were significantly higher in LFABP^-/- and IFABP^-/- mice under both diets. Collectively, these studies show that the ablation of LFABP or IFABP induced marked changes in the gut microbiota, and these were associated with HFD-induced phenotypic changes in these mice.

Unveiling the Role of the Fatty Acid Binding Protein 4 in the Metabolic-Associated Fatty Liver Disease

Metabolic-associated fatty liver disease (MAFLD), the main cause of chronic liver disease worldwide, is a progressive disease ranging from fatty liver to steatohepatitis (metabolic-associated steatohepatitis; MASH). Nevertheless, it remains underdiagnosed due to the lack of effective non-invasive methods for its diagnosis and staging. Although MAFLD has been found in lean individuals, it is closely associated with obesity-related conditions. Adipose tissue is the main source of liver triglycerides and adipocytes act as endocrine organs releasing a large number of adipokines and pro-inflammatory mediators involved in MAFLD progression into bloodstream. Among the adipocyte-derived molecules, fatty acid binding protein 4 (FABP4) has been recently associated with fatty liver and additional features of advanced stages of MAFLD. Additionally, emerging data from preclinical studies propose FABP4 as a causal actor involved in the disease progression, rather than a mere biomarker for the disease. Therefore, the FABP4 regulation could be considered as a potential therapeutic strategy to MAFLD. Here, we review the current knowledge of FABP4 in MAFLD, as well as its potential role as a therapeutic target for this disease.

Metabolic Enzyme Alterations and Astrocyte Dysfunction in a Murine Model of Alexander Disease With Severe Reactive Gliosis

Alexander disease (AxD) is a rare and fatal neurodegenerative disorder caused by mutations in the gene encoding glial fibrillary acidic protein (GFAP). In this report, a mouse model of AxD (GFAPTg;Gfap+/R236H) was analyzed that contains a heterozygous R236H point mutation in murine Gfap as well as a transgene with a GFAP promoter to overexpress human GFAP. Using label-free quantitative proteomic comparisons of brain tissue from GFAPTg;Gfap+/R236H versus wild-type mice confirmed upregulation of the glutathione metabolism pathway and indicated proteins were elevated in the peroxisome proliferator-activated receptor (PPAR) signaling pathway, which had not been reported previously in AxD. Relative protein-level differences were confirmed by a targeted proteomics assay, including proteins related to astrocytes and oligodendrocytes. Of particular interest was the decreased level of the oligodendrocyte protein, 2-hydroxyacylsphingosine 1-beta-galactosyltransferase (Ugt8), since Ugt8-deficient mice exhibit a phenotype similar to GFAPTg;Gfap+/R236H mice (e.g., tremors, ataxia, hind-limb paralysis). In addition, decreased levels of myelin-associated proteins were found in the GFAPTg;Gfap+/R236H mice, consistent with the role of Ugt8 in myelin synthesis. Fabp7 upregulation in GFAPTg;Gfap+/R236H mice was also selected for further investigation due to its uncharacterized association to AxD, critical function in astrocyte proliferation, and functional ability to inhibit the anti-inflammatory PPAR signaling pathway in models of amyotrophic lateral sclerosis (ALS). Within Gfap+ astrocytes, Fabp7 was markedly increased in the hippocampus, a brain region subjected to extensive pathology and chronic reactive gliosis in GFAPTg;Gfap+/R236H mice. Last, to determine whether the findings in GFAPTg;Gfap+/R236H mice are present in the human condition, AxD patient and control samples were analyzed by Western blot, which indicated that Type I AxD patients have a significant fourfold upregulation of FABP7. However, immunohistochemistry analysis showed that UGT8 accumulates in AxD patient subpial brain regions where abundant amounts of Rosenthal fibers are located, which was not observed in the GFAPTg;Gfap+/R236H mice.

Fatty acid-binding protein 4 circulating levels in non-segmental vitiligo

Background

Vitiligo is an acquired and progressive mucocutaneous disease resulting from the loss of active epidermal melanocytes. Metabolic syndrome (MetS) affects about 25% of the world’s population and is linked to inflammatory skin diseases including vitiligo. Fatty Acid-Binding Protein 4 (FABP4) is an intracellular lipid chaperone. FABP4 is closely associated with MetS.

Objectives

To evaluate the serum level of FABP4 in vitiligo patients and its relation to MetS in the investigated cases.

Methods

This case control study was conducted on 45 patients having non segmental vitiligo and 45 matched controls. Their lipid profile, blood glucose and serum FABP4 levels were measured.

Results

There were significant elevations in FABP4 (p < 0.001), cholesterol (p < 0.001), triglycerides (p = 0.005), and glucose (fasting [p = 0.001] and 2 hours post prandial [p < 0.001]) levels in patients in comparison with controls. MetS was significantly more prevalent among vitiligo patients (p < 0.001) and associated with high FABP4 serum levels (p = 0.037). In vitiligo patients, there were significant positive correlations between FABP4 serum levels and triglycerides (p = 0.047), cholesterol (p = 0.001) and LDL (p = 0.001) levels and negative correlation regarding HDL level (p = 0.009). FABP4 level was a significantly good diagnostic test for early detection of vitiligo (p < 0.001).

Study limitations

The small number of studied subjects.

Conclusions

FABP4 may play an active role in the disease process of vitiligo that could be mediated through associated dyslipidemia and hyperglycemia. FABP4 may be a marker of vitiligo helping in its early diagnosis, but it does not appear to be useful for determining vitiligo severity, activity or associated MetS.

Expression Profiles and Prognostic Value of FABPs in Colorectal Adenocarcinomas

Colorectal cancer (CRC) is one of the world's leading causes of cancer-related deaths; thus, it is important to detect it as early as possible. Obesity is thought to be linked to a large rise in the CRC incidence as a result of bad dietary choices, such as a high intake of animal fats. Fatty acid-binding proteins (FABPs) are a set of molecules that coordinate intracellular lipid responses and are highly associated with metabolism and inflammatory pathways. There are nine types of FABP genes that have been found in mammals, which are FABP1-7, FABP9, and FABP12. Each FABP gene has its own roles in different organs of the body; hence, each one has different expression levels in different cancers. The roles of FABP family genes in the development of CRC are still poorly understood. We used a bioinformatics approach to examine FABP family gene expression profiles using the Oncomine, GEPIA, PrognoScan, STRING, cBioPortal, MetaCore, and TIMER platforms. Results showed that the FABP6 messenger (m)RNA level is overexpressed in CRC cells compared to normal cells. The overexpression of FABP6 was found to be related to poor prognosis in CRC patients' overall survival. The immunohistochemical results in the Human Protein Atlas showed that FABP1 and FABP6 exhibited strong staining in CRC tissues. An enrichment analysis showed that high expression of FABP6 was significantly correlated with the role of microRNAs in cell proliferation in the development of CRC through the insulin-like growth factor (IGF) signaling pathway. FABP6 functions as an intracellular bile-acid transporter in the ileal epithelium. We looked at FABP6 expression in CRC since bile acids are important in the carcinogenesis of CRC. In conclusion, high FABP6 expression is expected to be a potential biomarker for detecting CRC at the early stage.

Mothers' cafeteria diet induced sex-specific changes in fat content, metabolic profiles, and inflammation outcomes in rat offspring

“Western diet” containing high concentrations of sugar and fat consumed during pregnancy contributes to development of obesity and diabetes type 2 in offspring. To mimic effects of this diet in animals, a cafeteria (CAF) diet is used. We hypothesized that CAF diet given to rats before, and during pregnancy and lactation differently influences fat content, metabolic and inflammation profiles in offspring. Females were exposed to CAF or control diets before pregnancy, during pregnancy and lactation. At postnatal day 25 (PND 25), body composition, fat contents were measured, and blood was collected for assessment of metabolic and inflammation profiles. We have found that CAF diet lead to sex-specific alterations in offspring. At PND25, CAF offspring had: (1) higher percentage of fat content, and were lighter; (2) sex-specific differences in levels of glucose; (3) higher levels of interleukin 6 (IL-6), interleukin-10 (IL-10) and tumor necrosis factor (TNF-α); (4) sex-specific differences in concentration of IL-6 and TNF-α, with an increase in CAF females; (5) higher level of IL-10 in both sexes, with a more pronounced increase in females. We concluded that maternal CAF diet affects fat content, metabolic profiles, and inflammation parameters in offspring. Above effects are sex-specific, with female offspring being more susceptible to the diet.

Adipocyte-Specific Fatty Acid-Binding Protein (AFABP) and Chemerin in Association with Gestational Diabetes: A Case-Control Study

BACKGROUND

Adipocytokines participate in regulating the inflammatory response in glucose homeostasis and type 2 diabetes. However, among these peptides, the role of adipocyte-specific fatty-acid-binding protein (AFABP), chemerin, and secreted protein acidic and rich in cysteine (SPARC) in gestational diabetes (GDM) has not been fully investigated.

METHOD

The maternal fasting level of adipocytokines of 53 subjects with GDM and 43 normal pregnant (NGDM) was measured using multiplex immunoassay at 24-28 weeks, before delivery, immediate postpartum, and 2-6 months postpuerperium.

RESULTS

Higher levels of AFABP were associated with a 3.7-fold higher risk of GDM. Low chemerin levels were associated with a 3.6-fold higher risk of GDM. Interleukin-10 (IL-10) was inversely associated with the risk of GDM. SPARC had no association with GDM. AFABP was directly correlated to interleukin-6 (r = 0.50), insulin resistance index (r = 0.26), and body mass index (r = 0.28) and inversely correlated to C-reactive protein (r = -0.27). Chemerin levels were directly and strongly correlated with IL-10 (r = 0.41) and interleukin-4 (r = 0.50) and inversely correlated to insulin resistance index (r = -0.23) in GDM but not NGDM. In the longitudinal assessment, there were no significant differences in AFABP and chemerin concentrations of both studied groups.

CONCLUSION

AFABP and chemerin were associated with a higher risk of GDM. These adipocytokines were related to insulin resistance, body mass index, and inflammation in pregnant women diagnosed with GDM.

Fatty acid binding protein 4 promotes autoimmune diabetes by recruitment and activation of pancreatic islet macrophages

Both innate and adaptive immune cells are critical players in autoimmune destruction of insulin-producing β cells in type 1 diabetes. However, the early pathogenic events triggering the recruitment and activation of innate immune cells in islets remain obscure. Here we show that circulating fatty acid binding protein 4 (FABP4) level was significantly elevated in patients with type 1 diabetes and their first-degree relatives and positively correlated with the titers of several islet autoantibodies. In nonobese diabetic (NOD) mice, increased FABP4 expression in islet macrophages started from the neonatal period, well before the occurrence of overt diabetes. Furthermore, the spontaneous development of autoimmune diabetes in NOD mice was markedly reduced by pharmacological inhibition or genetic ablation of FABP4 or adoptive transfer of FABP4-deficient bone marrow cells. Mechanistically, FABP4 activated innate immune responses in islets by enhancing the infiltration and polarization of macrophages to proinflammatory M1 subtype, thus creating an inflammatory milieu required for activation of diabetogenic CD8+ T cells and shift of CD4+ helper T cells toward Th1 subtypes. These findings demonstrate FABP4 as a possible early mediator for β cell autoimmunity by facilitating crosstalk between innate and adaptive immune cells, suggesting that pharmacological inhibition of FABP4 may represent a promising therapeutic strategy for autoimmune diabetes.

ROS Modulating Effects of Lingonberry (Vaccinium vitis-idaea L.) Polyphenols on Obese Adipocyte Hypertrophy and Vascular Endothelial Dysfunction

Oxidative stress and dysregulated adipocytokine secretion accompanying hypertrophied adipose tissue induce chronic inflammation, which leads to vascular endothelial dysfunction. The present study investigated the ability of anthocyanin (ACN) and non-anthocyanin polyphenol (PP) fractions from lingonberry fruit to mitigate adipose tissue hypertrophy and endothelial dysfunction using 3T3-L1 adipocytes and human umbilical vein endothelial cells (HUVECs). This study showed that the PP fraction decreased intracellular ROS generation in hypertrophied adipocytes by enhancing antioxidant enzyme expression (SOD2) and inhibiting oxidant enzyme expression (NOX4, iNOS). Moreover, PP and ACN fractions reduced triglyceride content in adipocytes accompanied by downregulation of the expression of lipogenic genes such as aP2, FAS, and DAGT1. Treatment with both fractions modulated the mRNA expression and protein secretion of key adipokines in hypertrophied adipocytes. Expression and secretion of leptin and adiponectin were, respectively, down- and upregulated. Furthermore, PP and ACN fractions alleviated the inflammatory response in TNF-α-induced HUVECs by inhibiting the expression of pro-inflammatory genes (IL-6, IL-1β) and adhesion molecules (VCAM-1, ICAM-1, SELE). The obtained results suggest that consuming polyphenol-rich lingonberry fruit may help prevent and treat obesity and endothelial dysfunction due to their antioxidant and anti-inflammatory actions.

Relationships of adipocyte-fatty acid binding protein and lipocalin 2 with risk factors and chronic complications in type 2 diabetes and effects of fenofibrate: A fenofibrate Intervention and event lowering in diabetes sub-study

AIMS

To investigate determinants of circulating levels of adipocyte-fatty acid binding protein (A-FABP) and lipocalin-2 (LCN2), their relationships with cardiovascular disease (CVD) and microvascular events, and effects of fenofibrate in type 2 diabetes (T2D).

METHODS

A-FABP and LCN2 were quantified in baseline plasma from 2000 T2D adults in a Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) trial sub-study and correlates thereof determined. In a subset (n = 200) adipokines were also measured on-trial.

RESULTS

Female sex, older age, higher body mass index (BMI), HbA1c, insulin resistance index, triglycerides, plasma creatinine and homocysteine, shorter diabetes duration, and use of oral hypoglycaemic agents alone were independent determinants of higher A-FABP. Higher BMI, fibrinogen and homocysteine, Caucasian race, and lower fasting glucose, HDL-cholesterol, apolipoprotein A-II and estimated glomerular filtration rate were independent predictors of higher LCN2 levels. Baseline A-FABP and LCN2 levels were associated with multiple new CVD and microvascular events over 5-years, though significance was lost after risk factor adjustment. Fenofibrate increased A-FABP but did not change LCN2 levels.

CONCLUSIONS

Baseline plasma A-FABP and LCN2 levels were associated with concurrent CVD risk factors, and on-trial chronic complications, likely mediated via traditional risk factors. Fenofibrate increased A-FABP modestly but did not affect LCN2 levels.

CLINICAL TRIAL REGISTRATION

ISRCTN 64783481.

Lower Pretreatment Gut Integrity Is Independently Associated With Fat Gain on Antiretroviral Therapy

BACKGROUND

Fat accumulation and insulin resistance remain a threat to the success of antiretroviral therapy (ART). The role of gut dysfunction in metabolic complications associated with ART initiation is unclear.

METHODS

Human immunodeficiency virus (HIV)-infected ART-naive participants were randomized to tenofovir disoproxil fumarate/emtricitabine plus atazanavir/ritonavir, darunavir/ritonavir, or raltegravir (RAL). Changes in the gut integrity markers zonulin, lipopolysaccharide-binding protein (LBP), and intestinal fatty acid and ileal bile acid binding proteins (I-FABP and I-BABP) were assessed over 96 weeks. Wilcoxon rank-sum tests were used to compare changes between groups and linear regression models to quantify associations between gut markers, insulin resistance, body mass index (BMI), and visceral, subcutaneous, and total adipose tissue (VAT, SAT, and TAT).

RESULTS

: 90% were male and 48% were White non-Hispanic. The median age was 36 years, HIV-1 ribonucleic acid was 4.56 log10 copies/mL, and CD4 count was 338 cells/µL. An overall 1.7-fold increase in I-FABP was observed throughout 96 weeks, with no difference between arms. Zonulin levels increased with RAL compared to protease inhibitor-based regimens (week 96, P = .02); minimal changes in I-BABP or LBP levels were observed. Higher baseline I-FABP levels were associated with increases in VAT, TAT, and BMI (16%, 9%, and 2.5%, respectively; P < .04) over 96 weeks.

CONCLUSIONS

While ART induces changes in the markers of gut barrier dysfunction, the extent to which they improve or worsen the gut barrier function remains unclear. Nevertheless, markers of gut barrier dysfunction in ART-naive individuals predict increases in total and visceral abdominal fat with treatment initiation.

Inhibition of Protein-tyrosine Phosphatase PTP1B and LMPTP Promotes Palmitate/Oleate-challenged HepG2 Cell Survival by Reducing Lipoapoptosis, Improving Mitochondrial Dynamics and Mitigating Oxidative and Endoplasmic Reticulum Stress

Objectives: Non-alcoholic fatty liver disease (NAFLD) is considered a well-known pathology that is determined without using alcohol and has emerged as a growing public health problem. Lipotoxicity is known to promote hepatocyte death, which, in the context of NAFLD, is termed lipoapoptosis. The severity of NAFLD correlates with the degree of hepatocyte lipoapoptosis. Protein–tyrosine phosphatases (PTP) including PTP1B and Low molecular weight PTP (LMPTP), are negative regulators of the insulin signaling pathway and are considered a promising therapeutic target in the treatment of diabetes. In this study, we hypothesized that the inhibition of PTP1B and LMPTP may potentially prevent hepatocyte apoptosis, mitochondrial dysfunction and endoplasmic reticulum (ER) stress onset, following lipotoxicity induced using a free fatty acid (FFA) mixture. Methods: HepG2 cells were cultured in the presence or absence of two PTP inhibitors, namely MSI-1436 and Compound 23, prior to palmitate/oleate overloading. Apoptosis, ER stress, oxidative stress, and mitochondrial dynamics were then evaluated by either MUSE or RT-qPCR analysis. Results: The obtained data demonstrate that the inhibition of PTP1B and LMPTP prevents apoptosis induced by palmitate and oleate in the HepG2 cell line. Moreover, mitochondrial dynamics were positively improved following inhibition of the enzyme, with concomitant oxidative stress reduction and ER stress abrogation. Conclusion: In conclusion, PTP’s inhibitory properties may be a promising therapeutic strategy for the treatment of FFA-induced lipotoxicity in the liver and ultimately in the management of the NAFLD condition.

The Biological Bases of Group 2 Pulmonary Hypertension

Pulmonary hypertension (PH) is a potentially fatal condition with a prevalence of around 1% in the world population and most commonly caused by left heart disease (PH-LHD). Usually, in PH-LHD, the increase of pulmonary pressure is only conditioned by the retrograde transmission of the left atrial pressure. However, in some cases, the long-term retrograde pressure overload may trigger complex and irreversible biomechanical and biological changes in the pulmonary vasculature. This latter clinical entity, designated as combined pre- and post-capillary PH, is associated with very poor outcomes. The underlying mechanisms of this progression are poorly understood, and most of the current knowledge comes from the field of Group 1-PAH. Treatment is also an unsolved issue in patients with PH-LHD. Targeting the molecular pathways that regulate pulmonary hemodynamics and vascular remodeling has provided excellent results in other forms of PH but has a neutral or detrimental result in patients with PH-LHD. Therefore, a deep and comprehensive biological characterization of PH-LHD is essential to improve the diagnostic and prognostic evaluation of patients and, eventually, identify new therapeutic targets. Ongoing research is aimed at identify candidate genes, variants, non-coding RNAs, and other biomarkers with potential diagnostic and therapeutic implications. In this review, we discuss the state-of-the-art cellular, molecular, genetic, and epigenetic mechanisms potentially involved in PH-LHD. Signaling and effective pathways are particularly emphasized, as well as the current knowledge on -omic biomarkers. Our final aim is to provide readers with the biological foundations on which to ground both clinical and pre-clinical research in the field of PH-LHD.

Brief Report: Gut Structural Damage: an Ongoing Process in Chronically Untreated HIV Infection

OBJECTIVE

To investigate the longitudinal changes of gut structural damage in chronically untreated HIV infection.

DESIGN

This is a 96-week prospective, single-site, cohort study of antiretroviral therapy-naive HIV-infected participants.

METHODS

Intestinal fatty acid-binding proteins (I-FABP) were used as a surrogate marker of gut structural damage. We assessed changes in I-FABP over 96 weeks and examined the associations between I-FABP, HIV variables, and inflammation. Spearman's correlations and linear mixed-effect models were used to study relationships among variables.

RESULTS

A total of 63 HIV-infected, antiretroviral therapy-naive patients were included in this analysis. At baseline, 76% were male; 62% were African American, with median age and body mass index of 40 years and 27 kg/m, respectively. Median HIV-RNA and CD4 T-cell counts were 5520 copies per milliliter and 588 cells per mm, respectively. I-FABP significantly increased from baseline to week 96 (mean change +333.9 pg/mL; P = 0.03), and this increase was associated with viral replication (rho = +0.4; P = 0.03). I-FABP levels were found to be associated with markers of inflammation: sTNFR-II (rho = 0.4, P = 0.02) and sVCAM-1 (rho = 0.04; P < 0.01) at all study time points. Lower baseline CD4 T-cell counts was found to be independently associated with I-FABP progression after adjusting for baseline characteristic variables (P = 0.02).

CONCLUSION

Gut structural damage is an ongoing process in the chronic phase of untreated HIV infection and is largely dependent on viral replication. I-FABP was found to be associated with worse immune function, increased inflammation, and viremia in chronically untreated HIV infection, supporting its role as a biomarker of intestinal barrier dysfunction.

Hepatoprotective Role of Eclipta alba against High Fatty Diet Treated Experimental Models - A Histopathological Study

Background

The hepatic injury due to oxidative stress was ameliorated through administration of an aqueous extract of Eclipta alba leaves and suggested that wedelolactone and demethylwedelolactone were the possible components of Eclipta alba behind the protective effect on liver as well as against liver disorders.

Objective

To study the hepato-protective effects of Eclipta alba on high fatty diet treated experimental models.

Material and methods

A total of 30 adult albino rats of Wistar strain weighing 165-215 grams, from the animal house of the Basaveshwara Medical College, Hospital and Research Centre, Chitradurga, were used for the present study: group 1 included animals fed with normal diet (control); group 2, animals treated with hyperlipidemic diet for eight weeks; group 3, animals treated with hyperlipidemic diet for eight weeks, followed by one week post treatment of Eclipta alba with normal diet; group 4, animals treated with hyperlipidemic diet for eight weeks, followed by two weeks post-treatment of Eclipta alba with normal diet; and group 5, animals treated with hyperlipidemic diet for eight weeks, followed by three weeks posttreatment of Eclipta alba with normal diet.

Results

In animals with high fat diet (30%), we observed the deposition of fat in the form of fat lobules in and around the hepatocytes, mononuclear in filtration in the liver parenchyma, dilation of blood vessels, necrotic foci and damaged hepatocytes.

Conclusion

The components of Eclipta alba like wedelolactone, demethylwedelolactone and saponins reduced fat deposition, mononuclear infiltration, and necrotic foci, and stimulated hepatocyte regeneration in the liver.

Serum Adipocyte Fatty Acid-Binding Protein Level is Negatively Associated with Vascular Reactivity Index Measured by Digital Thermal Monitoring in Kidney Transplant Patients

Adipocyte fatty acid-binding protein (A-FABP) is abundantly found in mature adipocytes and is involved in cardiovascular disease. Our aim is to investigate the association between serum A-FABP levels and endothelial function among kidney transplant (KT) patients. Fasting blood samples were obtained from 80 KT patients. Serum A-FABP levels were measured using a commercially available enzyme immunoassay kit. Endothelial function and vascular reactivity index (VRI) were measured using digital thermal monitoring test. In this study, VRI < 1.0, VRI 1.0-1.9, and VRI ≥ 2.0 were defined as poor, intermediate, and good vascular reactivity, respectively. There were 12 (15.0%), 30 (37.5%), and 38 (47.5%) KT patients categorized as having poor, intermediate, and good vascular reactivity, respectively. Increased serum levels of alkaline phosphatase (p = 0.012), γ-glutamyltranspeptidase (GGT; p = 0.032), and A-FABP (p < 0.001) were associated with decreased vascular reactivity. Multivariable forward stepwise linear regression analysis revealed that age (β = -0.283, adjusted R2 change = 0.072; p = 0.003) and serum log-A-FABP level (β = -0.514, adjusted R2 change = 0.268; p < 0.001) were significantly associated with VRI values in KT patients. We concluded that serum fasting A-FABP level is negatively associated with VRI values and plays a role in endothelial dysfunction of KT patients.

Inflammatory markers in children and adolescents with type 2 diabetes mellitus

This review examines the potential relationship between serum inflammation markers and type 2 diabetes mellitus (T2DM). Inflammation markers have been proposed as prognostic markers for the development of T2DM and its complications. Furthermore, modulation of the inflammatory process may offer future treatment strategies for T2DM. This review focuses on children and adolescents because there is usually little, if any, complications associated with other disease processes, use of medications, or active tobacco smoking. Furthermore, β-cell failure in young age cannot be solely explained by aging and exhaustion of β-cells due to insulin resistance. Pediatric studies have demonstrated that pro-inflammatory cytokines TNF-α, IL-6, IL-1β, IFNγ, PEDF, and fetuin A were increased in insulin resistance, while the anti-inflammatory cytokines adiponectin and omentin were decreased. Furthermore, TNF-α, fetuin A, FGF-21 were altered in obese children with T2DM suggesting a direct involvement in β-cell failure. Future studies focusing on children and adolescents may facilitate our understanding of T2DM as an inflammatory disease process.

Plasma fatty acid-binding protein 4 (FABP4) level is associated with abnormal QTc interval in patients with stable angina and chronic kidney disease

BACKGROUND

Fatty acid-binding protein 4 (FABP4) (also known as adipocyte FABP or adipocyte P2) is expressed in adipocytes, macrophages, and capillary endothelial cells. Previous studies have shown associations among plasma FABP4, insulin resistance, metabolic syndrome, diabetes mellitus, greater coronary plaque burden, coronary artery disease, heart failure, and mortality. However, little is known about the relationship between FABP4 level and prolonged QT interval. The aim of this study was to investigate whether plasma FABP4 level is associated with a prolonged QT interval by analyzing 12-lead electrocardiograms (ECGs) in patients with stable angina and chronic kidney disease (CKD).

METHODS

This study included 397 consecutive patients with stable angina and CKD who were enrolled in a disease management program. Plasma FABP4 concentrations were measured using enzyme-linked immunosorbent assays. A 12-lead ECG recording was obtained from each patient. We assessed the relationships between FABP4 levels (both as a continuous variable and stratified by tertile) at admission and corrected QT (QTc) prolongation.

RESULTS

Patients with an abnormal QTc interval had higher median plasma FABP4 levels than those with borderline and normal QTc intervals (15.9 ng/mL vs. 10.2 ng/mL vs. 8.5 ng/mL, respectively, P < 0.0001). Statistically significant associations were observed between plasma FABP4 levels and QTc interval (β = 0.267, P < 0.0001). Using multivariate and trend analyses, a higher concentration of plasma FABP4 level was independently associated with QTc prolongation in patients with stable angina and CKD.

CONCLUSION

In this study, plasma FABP4 levels were significantly higher in the patients with an abnormal QTc interval and were correlated with QTc prolongation. Further studies are required to elucidate whether plasma FABP4 plays a role in the pathogenesis of QTc prolongation.

High serum adipocyte fatty acid binding protein concentration linked with increased aortic arterial stiffness in patients with type 2 diabetes

BACKGROUND

Adipocyte fatty acid binding protein (A-FABP) is a novel adipokine that contributes to the development of metabolic disorder, type 2 diabetes mellitus (T2DM) and atherosclerosis. We determined the correlation between serum A-FABP and aortic stiffness in T2DM patients.

METHODS

Fasting blood samples were obtained from 156 patients with T2DM. Serum A-FABP concentration were determined using a commercial enzyme immunoassay. Carotid-femoral pulse wave velocity (cfPWV) was measured using SphygmoCor System, and cfPWV values of >10 m/s were defined as high aortic stiffness.

RESULTS

Sixty participants (38.4%) fell under the high aortic stiffness group. This group, compared to the control group, showed older age (P = .004), higher systolic blood pressure (P < .001), diastolic blood pressure (P = .027), urine albumin-to-creatinine ratio (P = .003), serum A-FABP (P < .001) and lower estimated glomerular filtration rate (P = .001). After adjusting for factors significantly associated with aortic stiffness using multivariable logistic regression analysis, serum A-FABP [OR = 1.029 (1.002-1.058), P = .039] was found to be an independent predictor of aortic stiffness in T2DM patients.

CONCLUSIONS

Serum A-FABP is positively correlated with aortic arterial stiffness in patients with T2DM.

S-Petasin isolated from Petasites japonicus exerts anti-adipogenic activity in the 3T3-L1 cell line by inhibiting PPAR-γ pathway signaling

S-Petasin from Petasites japonicus exerts anti-adipogenic activity in 3T3-L1 cells through inhibition of the expression of PPAR-γ.

The Role of PPAR-δ in Metabolism, Inflammation, and Cancer: Many Characters of a Critical Transcription Factor

Peroxisome proliferator-activated receptor-delta (PPAR-δ), one of three members of the PPAR group in the nuclear receptor superfamily, is a ligand-activated transcription factor. PPAR-δ regulates important cellular metabolic functions that contribute to maintaining energy balance. PPAR-δ is especially important in regulating fatty acid uptake, transport, and β-oxidation as well as insulin secretion and sensitivity. These salutary PPAR-δ functions in normal cells are thought to protect against metabolic-syndrome-related diseases, such as obesity, dyslipidemia, insulin resistance/type 2 diabetes, hepatosteatosis, and atherosclerosis. Given the high clinical burden these diseases pose, highly selective synthetic activating ligands of PPAR-δ were developed as potential preventive/therapeutic agents. Some of these compounds showed some efficacy in clinical trials focused on metabolic-syndrome-related conditions. However, the clinical development of PPAR-δ agonists was halted because various lines of evidence demonstrated that cancer cells upregulated PPAR-δ expression/activity as a defense mechanism against nutritional deprivation and energy stresses, improving their survival and promoting cancer progression. This review discusses the complex relationship between PPAR-δ in health and disease and highlights our current knowledge regarding the different roles that PPAR-δ plays in metabolism, inflammation, and cancer.

Inflammation Markers in Type 2 Diabetes and the Metabolic Syndrome in the Pediatric Population

PURPOSE OF REVIEW

Chronic inflammation, adipokines, and hepatokines have been identified as basis of insulin resistance and β cell failure in animal models. We present our current knowledge concerning the potential relationship between these cytokines, inflammation, metabolic syndrome (MetS), and type 2 diabetes mellitus (T2DM) in the pediatric population.

RECENT FINDINGS

Pro-inflammatory cytokines related to insulin resistance and MetS in children are tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-1β, interferon gamma, pigment epithelium-derived factor, chemerin, vaspin, and fetuin A. Anti-inflammatory cytokines associated with insulin resistance and MetS in children are leptin, adiponectin, omentin, fibroblast growth factor (FGF)-21, osteocalcin, and irisin. These anti-inflammatory cytokines are decreased (adiponectin, omentin, and osteocalcin) or increased (leptin, FGF-21, and irisin) in obesity suggesting a resistance state. TNF-α, fetuin A, and FGF-21 are altered in obese children with T2DM suggesting an involvement in β cell failure. These cytokines, adipokines, and hepatokines may be able to predict development of MetS and T2DM and have a potential therapeutic target ameliorating insulin resistance.

Association of serum adipocyte fatty acid-binding protein and apolipoprotein B /apolipoprotein A1 ratio with intima media thickness of common carotid artery in dyslipidemic patients

BACKGROUND

Diseases caused by atherosclerosis play the most important role in mortality and morbidity worldwide. Serum adipocyte fatty acid binding protein (A-FABP) seems to be a new promising marker to determine the risk of atherosclerosis.

OBJECTIVE

The aim of this study was to evaluate relationships between serum A-FABP levels in studied individuals and to assess the possibility of modeling the intima media thickness of the common carotid artery (C-IMT) using A-FABP levels and other observed characteristics.

METHODS

Seventy two Caucasian individuals were enrolled and divided into 3 groups: dyslipidemic patients with or without metabolic syndrome (MetS+, n=17; MetS-, n= 34) and controls (n=21).

RESULTS

There was confirmed the well-established risk profile of individuals with MetS (unfavorable lipid and lipoprotein profile, as well as increased parameters of insulin resistence and C-IMT). A-FABP concentrations in this group were significantly higher in comparison with both MetS- and controls.

CONCLUSION

Using multiple linear regression models of C-IMT values for all individual data, healthy controls and dyslipidemic patients without metabolic syndrome (MetS-) A-FABP levels were not revealed as an important predictor of C-IMT in our model. In contrast, age, gender, waist circumference, nonHDL cholesterol levels and ApoB/ApoA1 ratio were important repressors of C- IMT in study individuals. This finding may be attributed to the overwhelming effect of other more robust risk factors for atherosclerosis in these individuals.

High Levels of Serum Adipocyte Fatty Acid-binding Protein Predict Cardiovascular Events in Coronary Artery Disease Patients

Background: Adipocyte fatty acid-binding protein (A-FABP) is a cardiometabolic predictor of cardiovascular (CV) disease in humans. We evaluated the association between serum A-FABP levels and future CV events in patients with coronary artery disease (CAD). Methods: A total of 106 CAD patients were enrolled in this study between January and December 2012 and were followed-up until June 30, 2017. The primary endpoint was the incidence of major adverse CV events. Results: During a median follow-up period of 53 months, 44 CV events occurred. Patients with CV events presented higher systolic blood pressure (p = 0.020), total serum cholesterol (p = 0.047), and serum A-FABP levels (p < 0.001) compared with patients without CV events. Kaplan-Meier analysis showed that the cumulative incidence of CV events in the high A-FABP group (median A-FABP concentration of >17.63 ng/mL) was higher than that in the low A-FABP group (log-rank p < 0.001). Multivariate Cox analysis showed that triglycerides (hazard ratio (HR): 1.008, 95% confidence interval (CI): 1.001-1.016, p = 0.026) and serum A-FABP levels (HR: 1.027, 95% CI: 1.009-1.047, p = 0.004) were independently associated with CV events. Conclusion: Serum A-FABP level is a biomarker for future CV events in patients with CAD. Further prospective studies are needed to confirm the mechanisms underlying this association.

Fatty acid binding protein 4 enhances prostate cancer progression by upregulating matrix metalloproteinases and stromal cell cytokine production

Fatty acid binding protein 4 (FABP4) is an abundant protein in adipocytes, and its production is influenced by high-fat diet (HFD) or obesity. The prostate stromal microenvironment induces proinflammatory cytokine production, which is key for the development and progression of prostate cancer (PCa). Here, we show that high FABP4 expression and its secretion by PCa cells directly stimulated PCa cell invasiveness by upregulating matrix metalloproteinases through phosphatidylinositol 3-kinase and mitogen-activated protein kinase signaling pathways. In addition, prostate stromal cells augmented PCa cell invasiveness by secreting interleukin-8 and -6 in response to FABP4. This was abrogated by the FABP4 specific inhibitor, BMS309403. Furthermore, a mouse xenograft experiment showed HFD enhanced PCa metastasis and invasiveness by the upregulation of FABP4 and interleukin-8. Clinically, the serum level of FABP4 was significantly associated with an aggressive type of PCa rather than obesity. Taken together, FABP4 may enhance PCa progression and invasiveness by upregulating matrix metalloproteinases and cytokine production in the PCa stromal microenvironment, especially under HFD or obesity.

The protective effects of vitamin C on apoptosis, DNA damage and proteome of pufferfish (Takifugu obscurus) under low temperature stress

The aim of this study was to investigate the protective effects of vitamin C on apoptosis, DNA damage and proteome of pufferfish under low temperature stress. Six diets were formulated to contain 2.60, 48.90, 95.50, 189.83, 382.40, 779.53mg/kg vitamin C. After 8-week feeding trial, fish were exposed to low temperature challenge. The results showed that pufferfish receiving vitamin C diet exhibited a significant decrease in ROS production (48.9-189.83mg/kg vitamin C diet groups), cytoplasmic free-Ca²⁺ concentration (48.9-779.53mg/kg vitamin C diet groups), apoptotic cell ratio (95.5-779.53mg/kg vitamin C diet groups) and DNA damage (189.83-779.53mg/kg vitamin C diet groups) under low temperature stress in comparison with those of control. We also investigated the alteration in protein expression under low temperature stress by a comparative proteomic analysis. The results demonstrated that 24 protein spots showed significantly differential expression in the cold-stress-treated group compared with those of the control group, and 5 protein spots were successfully identified. Furthermore, comparative proteomic analysis revealed that vitamin C could increase expressed proteins related to energy metabolism, immune responses and cytoskeleton. These findings would be helpful to understand the protective effects of vitamin C against cold stress.

Radical scavenging-linked anti-adipogenic activity of Alnus firma extracts

The purpose of the present study was to investigate the antioxidant activity and anti-adipogenic effect of extracts from Alnus firma (A. firma), which is an edible plant that grows in mountainous areas. The total phenolic, flavonoid and anthocyanin content as well as the antioxidant activity of a 70% ethanolic extract of A. firma (AFE) was assessed. Furthermore, the effects of AFE on lipid accumulation and reactive oxygen species (ROS) production during adipogenesis of 3T3-L1 cells were investigated. The results revealed that the total phenolic, flavonoid and pro-anthocyanidin content of AFE as 436.26±3.30 mg gallic acid equivalents/g, 73.82±0.54 mg quercetin equivalents/g and 149.25±6.06 mg catechin equivalents/g, respectively. In addition, AFE exerted significant antioxidant effects in terms of 1,1-diphenyl-2-picryl hydrazyl radical scavenging activity, 2,2′-azino-bis(3-ethylbenzothia-zoline-6-sulfonic acid) radical scavenging activity, reducing power, oxygen radical absorbance capacity and nitric oxide radical scavenging activity. As for its anti-adipogenic activity, AFE significantly inhibited ROS production and lipid accumulation during adipogenesis of 3T3-L1 cells compared with those in control cells. In addition, AFE regulated adipogenic transcription factors including peroxisome proliferator-activated receptor-γ, CCAAT/enhance-binding protein α and adipocyte protein 2. These results indicated that A. firma is a potential candidate for a functional food supplement.

Serum adipocyte fatty acid-binding protein level is associated with arterial stiffness quantified with cardio-ankle vascular index in kidney transplant patients

BACKGROUND

Arterial stiffness is an established marker of cardiovascular risk and an independent predictor of cardiovascular disease (CVD) events and mortality in kidney transplant (KT) patients. Adipocyte fatty acid-binding protein (A-FABP), a novel adipokine, is positively associated with atherosclerosis. The present study evaluated the relationship between fasting circulating A-FABP and peripheral arterial stiffness using the cardio-ankle vascular index (CAVI) in KT patients.

METHODS

Fasting blood samples were collected from 74 KT patients, and serum A-FABP levels were measured using an enzyme immunoassay. CAVI was calculated using a waveform device (CAVI-VaSera VS-1000). The cutoff values for high and low levels of arterial stiffness were defined by the CAVI values of ≥9 and <9, respectively.

RESULTS

Thirty-four patients (45.9%) were classified into the high arterial stiffness group. Compared with the low arterial stiffness group, the high arterial stiffness group had higher values for age (p = 0.015), systolic blood pressure (p < 0.001), pulse pressure (p < 0.001), duration of kidney transplantation (p = 0.005), serum total cholesterol and triglyceride levels (p = 0.033 and 0.047, respectively), glomerular filtration rate (p = 0.019), fasting glucose levels (p = 0.012), and serum A-FABP levels (p < 0.001). Multivariate forward stepwise linear regression analysis showed that age (p = 0.004), systolic blood pressure (p = 0.001), and serum A-FABP levels (p = 0.003) were independent predictors of CAVI value in KT patients.

CONCLUSION

Serum fasting A-FABP level is positively associated with peripheral arterial stiffness in KT patients.

17β-estradiol upregulates oxytocin and the oxytocin receptor in C2C12 myotubes

Background

The endocrinology of skeletal muscle is highly complex and many issues about hormone action in skeletal muscle are still unresolved. Aim of the work is to improve our knowledge on the relationship between skeletal muscle and 17β-estradiol.

Methods

The skeletal muscle cell line C2C12 was treated with 17β-estradiol, the oxytocin peptide and a combination of the two hormones. The mRNA levels of myogenic regulatory factors, myosin heavy chain, oxytocin, oxytocin receptor and adipogenic factors were analysed in C2C12 myotubes.

Results

It was demonstrated that C2C12 myoblasts and myotubes express oxytocin and its receptor, in particular the receptor levels physiologically increase in differentiated myotubes. Myotubes treated with 17β-estradiol overexpressed oxytocin and oxytocin receptor genes by approximately 3- and 29-fold, respectively. A decrease in the expression of fatty acid binding protein 4 (0.62-fold), a fat metabolism-associated gene, was observed in oxytocin-treated myotubes. On the contrary, fatty acid binding protein 4 was upregulated (2.66-fold) after the administration of the combination of 17β-estradiol and oxytocin. 17β-estradiol regulates oxytocin and its receptor in skeletal muscle cells and they act in a synergic way on fatty acid metabolism.

Discussion

Oxytocin and its receptor are physiologically regulated along differentiation. 17β-estradiol regulates oxytocin and its receptor in skeletal muscle cells. 17β-estradiol and oxytocin act in a synergic way on fatty acid metabolism. A better understanding of the regulation of skeletal muscle homeostasis by estrogens and oxytocin peptide could contribute to increase our knowledge of muscle and its metabolism.

A-FABP mediates adaptive thermogenesis by promoting intracellular activation of thyroid hormones in brown adipocytes

The adipokine adipocyte fatty acid-binding protein (A-FABP) has been implicated in obesity-related cardio-metabolic complications. Here we show that A-FABP increases thermogenesis by promoting the conversion of T4 to T3 in brown adipocytes. We find that A-FABP levels are increased in both white (WAT) and brown (BAT) adipose tissues and the bloodstream in response to thermogenic stimuli. A-FABP knockout mice have reduced thermogenesis and whole-body energy expenditure after cold stress or after feeding a high-fat diet, which can be reversed by infusion of recombinant A-FABP. Mechanistically, A-FABP induces the expression of type-II iodothyronine deiodinase in BAT via inhibition of the nuclear receptor liver X receptor α, thereby leading to the conversion of thyroid hormone from its inactive form T4 to active T3. The thermogenic responses to T4 are abrogated in A-FABP KO mice, but enhanced by A-FABP. Thus, A-FABP acts as a physiological stimulator of BAT-mediated adaptive thermogenesis.

Impact of cardiopulmonary bypass surgery on cytokines in epicardial adipose tissue: comparison with subcutaneous fat

BACKGROUND

Cardiac surgery and cardiopulmonary bypass (CPB) have been shown to stimulate a systemic inflammatory response which has been associated with adverse postoperative outcomes. Adipose tissue, both epicardial (EAT) and subcutaneous (SAT), is a known source of inflammatory cytokines, but its role in the pathophysiology of surgery- and CPB-induced systemic inflammatory response has not been fully elucidated. Therefore, we conducted a study to establish levels of selected cytokines in EAT and SAT prior to and after surgery with CPB.

METHODS

Adipose tissue samples were obtained from patients undergoing planned cardiac surgery on CPB. Samples from EAT and SAT were collected before and immediately after CPB. Levels of tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6), adipocyte fatty acid-binding protein (AFABP), leptin and adiponectin were determined by ELISA, which were adjusted for a total concentration of proteins in the individual samples.

RESULTS

Samples from 77 patients (mean age 67.68 ± 11.5 years) were obtained and analysed. Leptin, adiponectin, TNF-α and AFABP were shown to decrease their concentrations statistically significantly in the EAT after CPB while no statistically significant drop was observed in the SAT. On the contrary, IL-6 showed only a slight and statistically insignificant decrease in the EAT after CPB and it was in the SAT where a statistically significant drop was observed.

DISCUSSION

One of the most relevant findings of this study was the marked decrease in EAT levels of TNF-α, AFABP, leptin and adiponectin after the CPB termination. Our results suggest that EAT might serve as a pool of cytokines which are released into the circulation in reaction to surgery with CPB. Should these novel findings be confirmed, new strategies to assess and possibly reduce EAT contribution on adverse outcomes of cardiac surgery may be developed.