Obesity modulates the expression of haptoglobin in the white adipose tissue via TNFalpha

An Update on the Role and Potential Molecules in Relation to Ruminococcus gnavus in Inflammatory Bowel Disease, Obesity and Diabetes Mellitus

Ruminococcus gnavus (R. gnavus) is a gram-positive anaerobe commonly resides in the human gut microbiota. The advent of metagenomics has linked R. gnavus with various diseases, including inflammatory bowel disease (IBD), obesity, and diabetes mellitus (DM), which has become a growing area of investigation. The initial focus of research primarily centered on assessing the abundance of R. gnavus and its potential association with disease presentation, taking into account variations in sample size, sequencing and analysis methods. However, recent investigations have shifted towards elucidating the underlying mechanistic pathways through which R. gnavus may contribute to disease manifestation. In this comprehensive review, we aim to provide an updated synthesis of the current literature on R. gnavus in the context of IBD, obesity, and DM. We critically analyze relevant studies and summarize the potential molecular mediators implicated in the association between R. gnavus and these diseases. Across numerous studies, various molecules such as methylation-controlled J (MCJ), glucopolysaccharides, ursodeoxycholic acid (UDCA), interleukin(IL)-10, IL-17, and capric acid have been proposed as potential contributors to the link between R. gnavus and IBD. Similarly, in the realm of obesity, molecules such as hydrogen peroxide, butyrate, and UDCA have been suggested as potential mediators, while glycine ursodeoxycholic acid (GUDCA) has been implicated in the connection between R. gnavus and DM. Furthermore, it is imperative to emphasize the necessity for additional studies to evaluate the potential efficacy of targeting pathways associated with R. gnavus as a viable strategy for managing these diseases. These findings have significantly expanded our understanding of the functional role of R. gnavus in the context of IBD, obesity, and DM. This review aims to offer updated insights into the role and potential mechanisms of R. gnavus, as well as potential strategies for the treatment of these diseases.

N-glycosylation of disease-specific haptoglobin for the early screening of diabetic retinopathy

PURPOSE

Diabetic retinopathy (DR), as one of the microvascular complications of diabetes, is a leading cause of acquired vision loss. Most DR cases are detected in the advanced stage through fundoscopy, making molecular biomarkers urgently needed for early diagnosis of DR.

EXPERIMENTAL DESIGN

Serum disease-specific haptoglobin-β (Hp-β) chains of 100 patients with type 2 diabetes mellitus (T2DM) and 156 T2DM patients with non-proliferative diabetic retinopathy (NPDR) were separated using polyacrylamide gel electrophoresis. After in-gel digestion and enrichment, the intact N-glycopeptides were detected by mass spectrometry.

RESULTS

Fucosylation of Hp-β was significantly increased and sialylation of Hp-β was significantly decreased in background DR (BDR, an early-stage DR) patients compared with non-diabetic retinopathy patients (p < 0.05) and yielded area under curves (AUCs) of 0.801 and 0.829 in training and validation groups, respectively, which had an advantage over glycated hemoglobin A1c (AUC ≤ 0.691). Moreover, a significant increase in sialylated Hp-β was found in severe NPDR patients compared with BDR patients and yielded an AUC of 0.828 to distinguish severe NPDR from BDR.

CONCLUSION

Changes in Hp-β glycosylation are closely related to DR, and may be used for early diagnosis and screening of DR.

Pleurotus abieticola Polysaccharide Alleviates Hyperlipidemia Symptoms via Inhibition of Nuclear Factor-κB/Signal Transducer and Activator of Transcription 3-Mediated Inflammatory Responses

Hyperlipidemia (HLP) is a metabolic syndrome induced by obesity, which has been widely recognized as a significant threat to human health. Pleurotus abieticola, an edible lignin-degrading fungus, remains relatively understudied in terms of its bioactivity and medicinal properties. In this study, the lipid-lowering effect of Pleurotus abieticola polysaccharide (PAPS1) was systematically explored in high-fat diet (HFD)-induced HLP mice. The findings demonstrated that the administration of PAPS1 significantly inhibited bodyweight gain, ameliorated blood glucose and lipid levels, reduced fat accumulation, and mitigated hepatic injury in HLP mice. In addition, PAPS1 demonstrated the capability to increase the levels of three distinct fecal metabolites while simultaneously reducing the levels of eight other fecal metabolites in HLP mice. According to biological detection, PAPS1 reduced the hepatic level of reactive oxygen species (ROS) and pro-inflammatory factors, such as tumor necrosis factor (TNF)-α and interleukin (IL)-1β, -6, -17A, -22, and -23, and increased the expression of anti-inflammatory factor IL-10. Combined with proteomics, Western blot and immunohistochemistry analysis showed that PAPS1 exerted suppressive effects on inflammation and oxidative damage by inhibiting the nuclear factor-κB (NF-κB)/signal transducer and activator of transcription 3 (STAT3) signaling pathway in HLP mice. These findings offer evidence supporting the effectiveness of PAPS1 as a therapeutic agent in reducing lipid levels through its targeting of chronic inflammation.

Impact of 10-day bed rest on serum levels of irisin and markers of musculoskeletal metabolism

The bed rest (BR) is a ground-based model to simulate microgravity mimicking skeletal-muscle alterations as in spaceflight. Molecular coupling between bone and muscle might be involved in physiological and pathological conditions. Thus, the new myokine irisin and bone-muscle turnover markers have been studied during and after 10 days of BR. Ten young male individuals were subjected to 10 days of horizontal BR. Serum concentrations of irisin, myostatin, sclerostin, and haptoglobin were assessed, and muscle tissue gene expression on vastus lateralis biopsies was determined. During 10-days BR, we observed no significant fluctuation levels of irisin, myostatin, and sclerostin. Two days after BR (R+2), irisin serum levels significantly decreased while myostatin, sclerostin, and haptoglobin were significantly increased compared with BR0. Gene expression of myokines, inflammatory molecules, transcription factors, and markers of muscle atrophy and senescence on muscle biopsies were not altered, suggesting that muscle metabolism of young, healthy subjects is able to adapt to the hypomobility condition during 10-day BR. However, when subjects were divided according to irisin serum levels at BR9, muscle ring finger-1 mRNA expression was significantly lower in subjects with higher irisin serum levels, suggesting that this myokine may prevent the triggering of muscle atrophy. Moreover, the negative correlation between p21 mRNA and irisin at BR9 indicated a possible inhibitory effect of the myokine on the senescence marker. In conclusion, irisin could be a prognostic marker of hypomobility-induced muscle atrophy, and its serum levels could protect against muscle deterioration by preventing and/or delaying the expression of atrophy and senescence cellular markers.

Role of Haptoglobin as a Marker of Muscular Improvement in Patients with Multiple Sclerosis after Administration of Epigallocatechin Gallate and Increase of Beta-Hydroxybutyrate in the Blood: A Pilot Study

Here, we report on the role of haptoglobin (Hp), whose expression depends on the synthesis of interleukin 6 (IL-6), related to the pathogenesis of multiple sclerosis (MS), as a possible marker of muscle improvement achieved after treatment with the polyphenol epigallocatechin gallate (EGCG) and an increase in the ketone body beta-hydroxybutyrate (BHB) in the blood. After 4 months of intervention with 27 MS patients, we observed that Hp does not significantly increase, alongside a significant decrease in IL-6 and a significant increase in muscle percentage. At the same time, Hp synthesis is considerably and positively correlated with IL-6 both before and after treatment; while this correlation occurs significantly reversed with muscle percentage before treatment, no correlation is evident after the intervention. These results seem to indicate that Hp could be a marker of muscle status and could be a diagnosis tool after therapeutic intervention in MS patients.

Poor Clearance of Free Hemoglobin Due to Lower Active Haptoglobin Availability is Associated with Osteoarthritis Inflammation

Introduction

Circulating plasma proteins play an important role in various diseases, and analysis of the plasma proteome has led to the discovery of various disease biomarkers. Osteoarthritis (OA) is the most common chronic joint disease, mostly affecting people of older age. OA typically starts as a focal disease (in a single compartment, typically treated with unicompartmental knee replacement), and then progresses to the other compartments (if not treated in time, typically treated with total knee replacement). For this, identification of differential proteins was carried out in plasma samples of OA cases and compared with healthy controls. The aim of this study was to identify circulatory differentially expressed proteins (DEPs) in knee-OA patients undergoing total knee replacement or unicompartmental knee replacement compared to healthy controls and assess their role, in order to have better understanding of the etiology behind OA pathophysiology.

Methods

DEPs were identified with two-dimensional gel electrophoresis (2DE) and isobaric tags for relative and absolute quantification (iTRAQ), followed by liquid chromatography with tandem mass spectrometry. Validation of DEPs was carried out using Western blot and ELISA. Posttranslational modifications were checked after running native gel using purified protein from patients, followed by detection of autoantibodies.

Results

In total, 52 DEPs were identified, among which 45 were distinct DEPs. Haptoglobin (Hp) was identified as one of the most significantly upregulated proteins in OA (P=0.005) identified by both 2DE and iTRAQ. Decreased levels of Hp tetramers and increased levels of autoantibodies against Hpβ were observed in OA plasma.

Conclusion

Our data suggest that poor clearance of free hemoglobin and low levels of Hp tetramers may be associated with OA pathogenesis and inflammation.

Progress on haptoglobin and metabolic diseases

Haptoglobin (Hp) is an acidic glycoprotein, existing in the serum and other body fluids of human beings and a variety of mammals. Hp is produced in the liver, white adipose tissue, and the kidney. The genetic polymorphisms and different phenotypes of Hp have different biological functions. Hp has antibacterial, antioxidant, and angiogenic effects and is associated with multiple diseases including simple obesity, vascular complications of diabetes mellitus, nonalcoholic fatty liver disease, hypertension, blood diseases, autoimmune diseases, and malignant tumors. Hp also participates in many life activities, indicating the importance of Hp in further studies. Previously, we found that the expression of serum Hp changed after treatment of simple obesity patients in clinical trials. However, the specific mechanism of Hp in patients with simple obesity is still unclear. The purpose of this article is to introduce recent research progress on Hp, emphasizing the relationship between Hp and the development of metabolic disease, which will improve the understanding of the functions of Hp underlying metabolic diseases and discuss future research directions.

Identification of Key Pathways and Genes in Obesity Using Bioinformatics Analysis and Molecular Docking Studies

Obesity is an excess accumulation of body fat. Its progression rate has remained high in recent years. Therefore, the aim of this study was to diagnose important differentially expressed genes (DEGs) associated in its development, which may be used as novel biomarkers or potential therapeutic targets for obesity. The gene expression profile of E-MTAB-6728 was downloaded from the database. After screening DEGs in each ArrayExpress dataset, we further used the robust rank aggregation method to diagnose 876 significant DEGs including 438 up regulated and 438 down regulated genes. Functional enrichment analysis was performed. These DEGs were shown to be significantly enriched in different obesity related pathways and GO functions. Then protein-protein interaction network, target genes - miRNA regulatory network and target genes - TF regulatory network were constructed and analyzed. The module analysis was performed based on the whole PPI network. We finally filtered out STAT3, CORO1C, SERPINH1, MVP, ITGB5, PCM1, SIRT1, EEF1G, PTEN and RPS2 hub genes. Hub genes were validated by ICH analysis, receiver operating curve (ROC) analysis and RT-PCR. Finally a molecular docking study was performed to find small drug molecules. The robust DEGs linked with the development of obesity were screened through the expression profile, and integrated bioinformatics analysis was conducted. Our study provides reliable molecular biomarkers for screening and diagnosis, prognosis as well as novel therapeutic targets for obesity.

The Intake of a Cafeteria Diet in Nursing Rats Alters the Breast Milk Concentration of Proteins Important for the Development of Offspring

We aimed to analyse the effects of maternal intake of an unbalanced diet during lactation in the composition and the levels of proteins present in milk. Milk samples from control nursing dams (C-dams) or from nursing dams fed a cafeteria diet during lactation (CAF-dams) were obtained. We conducted a proteomic approach to identify significantly altered proteins in breast milk of C- and CAF-dams, and evaluated the levels of leptin, adiponectin and irisin for their implication in energy homeostasis. One-dimensional SDS-polyacrylamide gel electrophoresis (SDS-PAGE), followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), revealed that the bands that presented a lower intensity in CAF-dams than control contain some caseins (α-S1-casein, α-S2-casein like B, and β-casein), α-lactalbumin and haptoglobin. Leptin and adiponectin levels were greater in the breast milk of CAF-dams than in controls, while levels of irisin were lower. In summary, the relative concentration of bioactive peptides was influenced by maternal diet consumption during lactation; these changes at early stages of life could influence the phenotypic traits of the offspring.

Synergistic Effects of Heat-Killed Kefir Paraprobiotics and Flavonoid-Rich Prebiotics on Western Diet-Induced Obesity

The synergistic anti-obesity effect of paraprobiotic heat-killed lactic acid bacteria (HLAB) and prebiotics has not been studied. To determine the anti-obesity properties of prebiotic polyphenol-rich wine grape seed flour (GSF) and paraprobiotic HLAB, C57BL/6J mice were administered a high-fat and high-fructose diet (HFFrD) with 5% microcrystalline cellulose (CON), HFFrD supplemented with 2.5% GSF, HFFrD with orally administered HLAB, or HFFrD with a combination of GSF and orally administered HLAB (GSF+HLAB) for 8 weeks. Compared with the CON group, the GSF and HLAB groups both showed significant reductions in HFFrD-induced body weight gain and adipose tissue weights (p < 0.05). Interestingly, combined supplementation with GSF and HLAB revealed statistically significant synergistic effects on body weight gain, visceral adiposity, and plasma triacylglycerol concentrations (p < 0.05). The synergistic action was significantly related to a decreased adipocyte gene expression in fatty acid synthesis and inflammation metabolism. In conclusion, the combination of prebiotic GSF and paraprobiotic kefir HLAB is potentially useful, as natural food ingredients, in the prevention of obesity and obesity-related diseases, especially for immunocompromised individuals.

Iron Metabolism in Obesity and Metabolic Syndrome

Obesity is an excessive adipose tissue accumulation that may have detrimental effects on health. Particularly, childhood obesity has become one of the main public health problems in the 21st century, since its prevalence has widely increased in recent years. Childhood obesity is intimately related to the development of several comorbidities such as nonalcoholic fatty liver disease, dyslipidemia, type 2 diabetes mellitus, non-congenital cardiovascular disease, chronic inflammation and anemia, among others. Within this tangled interplay between these comorbidities and associated pathological conditions, obesity has been closely linked to important perturbations in iron metabolism. Iron is the second most abundant metal on Earth, but its bioavailability is hampered by its ability to form highly insoluble oxides, with iron deficiency being the most common nutritional disorder. Although every living organism requires iron, it may also cause toxic oxygen damage by generating oxygen free radicals through the Fenton reaction. Thus, iron homeostasis and metabolism must be tightly regulated in humans at every level (i.e., absorption, storage, transport, recycling). Dysregulation of any step involved in iron metabolism may lead to iron deficiencies and, eventually, to the anemic state related to obesity. In this review article, we summarize the existent evidence on the role of the most recently described components of iron metabolism and their alterations in obesity.

Haptoglobin: From hemoglobin scavenging to human health

Haptoglobin (Hp) belongs to the family of acute-phase plasma proteins and represents the most important plasma detoxifier of hemoglobin (Hb). The basic Hp molecule is a tetrameric protein built by two α/β dimers. Each Hp α/β dimer is encoded by a single gene and is synthesized as a single polypeptide. Following post-translational protease-dependent cleavage of the Hp polypeptide, the α and β chains are linked by disulfide bridge(s) to generate the mature Hp protein. As human Hp gene is characterized by two common Hp1 and Hp2 alleles, three major genotypes can result (i.e., Hp1-1, Hp2-1, and Hp2-2). Hp regulates Hb clearance from circulation by the macrophage-specific receptor CD163, thus preventing Hb-mediated severe consequences for health. Indeed, the antioxidant and Hb binding properties of Hp as well as its ability to stimulate cells of the monocyte/macrophage lineage and to modulate the helper T-cell type 1 and type 2 balance significantly associate with a variety of pathogenic disorders (e.g., infectious diseases, diabetes, cardiovascular diseases, and cancer). Alternative functions of the variants Hp1 and Hp2 have been reported, particularly in the susceptibility and protection against infectious (e.g., pulmonary tuberculosis, HIV, and malaria) and non-infectious (e.g., diabetes, cardiovascular diseases and obesity) diseases. Both high and low levels of Hp are indicative of clinical conditions: Hp plasma levels increase during infections, inflammation, and various malignant diseases, and decrease during malnutrition, hemolysis, hepatic disease, allergic reactions, and seizure disorders. Of note, the Hp:Hb complexes display heme-based reactivity; in fact, they bind several ferrous and ferric ligands, including O₂, CO, and NO, and display (pseudo-)enzymatic properties (e.g., NO and peroxynitrite detoxification). Here, genetic, biochemical, biomedical, and biotechnological aspects of Hp are reviewed.

Causal Association of Haptoglobin With Obesity in Mexican Children: A Mendelian Randomization Study

CONTEXT

Little is known about the association between haptoglobin level and cardiometabolic traits. A previous genome-wide association study identified rs2000999 in the HP gene as the stronger genetic contributor to serum haptoglobin level in European populations.

OBJECTIVE AND DESIGN

We investigated the association of HP rs2000999 with serum haptoglobin and childhood and adult obesity in up to 540/697 and 592/691 Mexican cases and controls, respectively. Anthropometric and biochemical data were collected. Serum haptoglobin was measured by an immunoturbidimetry assay. HP rs2000999 was genotyped using the TaqMan technology. Mendelian randomization analysis was performed using the Wald and inverse variance weighting methods.

RESULTS

Haptoglobin level was positively associated with childhood and adult obesity. HP rs2000999 G allele was positively associated with haptoglobin level in children and adults. HP rs2000999 G allele was positively associated with childhood but not adult obesity. The association between HP rs2000999 and childhood obesity was removed after adjusting for haptoglobin level. In a Mendelian randomization analysis, haptoglobin level genetically predicted by HP rs2000999 showed a significant causal effect on childhood obesity by the Wald and inverse variance weighting methods.

CONCLUSION

Our data provide evidence for the first time for a causal positive association between serum haptoglobin level and childhood obesity in the Mexican population. Our study contributes to the genetic elucidation of childhood obesity and proposes haptoglobin as an important biomarker and treatment target for obesity.

Sick fat: the good and the bad of old and new circulating markers of adipose tissue inflammation

Adipose tissue (AT) is one of the largest endocrine organs contributing to metabolic homeostasis. The functional pleiotropism of AT depends on its ability to secrete a large number of hormones, cytokines, extracellular matrix proteins and growth factors, all influencing many local and systemic physiological and pathophysiological processes. In condition of chronic positive energy balance, adipocyte expansion, hypoxia, apoptosis and stress all lead to AT inflammation and dysfunction, and it has been demonstrated that this sick fat is a main risk factor for many metabolic disorders, such as type 2 diabetes mellitus, fatty liver, cardiovascular disease and cancer. AT dysfunction is tightly associated with aberrant secretion of bioactive peptides, the adipocytokines, and their blood concentrations often reflect the expression in the AT. Despite the existence of an association between AT dysfunction and systemic pro-inflammatory state, most of the circulating molecules detectable in obese and dysmetabolic individuals do not identify specifically the condition of sick fat. Based on this premise, this review provides a concise overview of "classic" and novel promising adipocytokines associated with AT inflammation and discusses possible critical approaches to their interpretation in clinical practice.

Influence of Obesity on Serum Concentrations of Acute-Phase Proteins in Horses

Obesity in human and veterinary medicine is one of the most complex challenges within emerging diseases in the context of health. The problem of obesity in horses results in severe comorbidities; therefore, acute-phase proteins should be investigated for fluctuations increasing or decreasing by at least 25% in response to inflammation; these are candidates for future biomarkers and might provide new perspectives on early diagnosis and prognosis. Serum samples were analyzed in nine healthy animals (C) and nine obese animals (O). The proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the concentrations determined by computerized densitometry; matrix assisted laser desorption ionization time of flight mass spectrometry/TOF mass spectrometry was performed to identify the proteins, and the results obtained were compared to the Equidae and Metazoa taxon protein database deposited in UNIPROT using the MASCOT application. Three proteins presented a difference between the groups; ceruloplasmin (Cp), α₁-antitrypsin (α₁-antitryp), and haptoglobin (Hp). The behavior of the Cp and Hp proteins was compatible with the available literature for obesity in other species. The α₁-antitryp protein was positively correlated with leptin, demonstrating the need for further investigations. The initial study of these proteins was important due to the lack of information available on the influence of obesity on inflammatory biomarkers in horses in Brazil; therefore, we sought to verify a possible association between overweight and changes in the studied variables.

Proteomics approach to identify serum biomarkers associated with the progression of diabetes in Korean patients with abdominal obesity

Type 2 diabetes is a metabolic disease with a group of metabolic derangements and inflammatory reactants in the serum. Despite the substantial public health implications, markers of diabetes progression with abdominal obesity are still needed to facilitate early detection and treatment. In this study, we performed a proteomic approach to identify differential target proteins underlying diabetes progression in patients with abdominal obesity. Proteomic differences were investigated in the serum of controls and patients with prediabetes or diabetes with or without abdominal obesity by 2-DE combined with MALDI-TOF-MS. Proteomics data were validated by western blot analyses and major protein-protein interactions were assessed using a network analysis with String database. Among 245 matched protein spots, 36 exhibited marked differences in normal patients with abdominal obesity, prediabetes, and diabetes compared to levels in normal patients without abdominal obesity. Seven (Alpha-1-antichymotrypsin, Alpha-1-antitrypsin, Apolipoprotein A-I, haptoglobin, retinol-binding protein 4, transthyretin, and zinc-alpha2-glycoprotein) of these spots exhibited significant differences between normal and prediabetes/diabetes patients. After a network analysis, functional annotation using Gene Ontology indicated that most of the identified proteins were involved in lipid transport, lipid localization, and the regulation of serum lipoprotein particle levels. Our results indicated that variation in the levels of these identified protein biomarkers has been reported in normal, prediabetes and diabetic Assessment of the levels of these biomarkers may contribute to the development of biomarkers for not only early diagnosis but also in prognosis of diabetes mellitus type 2.

Pnpla3 silencing with antisense oligonucleotides ameliorates nonalcoholic steatohepatitis and fibrosis in Pnpla3 I148M knock-in mice

Objective

Nonalcoholic fatty liver disease (NAFLD) is becoming a leading cause of advanced chronic liver disease. The progression of NAFLD, including nonalcoholic steatohepatitis (NASH), has a strong genetic component, and the most robust contributor is the patatin-like phospholipase domain-containing 3 (PNPLA3) rs738409 encoding the 148M protein sequence variant. We hypothesized that suppressing the expression of the PNPLA3 148M mutant protein would exert a beneficial effect on the entire spectrum of NAFLD.

Methods

We examined the effects of liver-targeted GalNAc₃-conjugated antisense oligonucleotide (ASO)-mediated silencing of Pnpla3 in a knock-in mouse model in which we introduced the human PNPLA3 I148M mutation.

Results

ASO-mediated silencing of Pnpla3 reduced liver steatosis (p = 0.038) in homozygous Pnpla3 148M/M knock-in mutant mice but not in wild-type littermates fed a steatogenic high-sucrose diet. In mice fed a NASH-inducing diet, ASO-mediated silencing of Pnpla3 reduced liver steatosis score and NAFLD activity score independent of the Pnpla3 genotype, while reductions in liver inflammation score (p = 0.018) and fibrosis stage (p = 0.031) were observed only in the Pnpla3 knock-in 148M/M mutant mice. These responses were accompanied by reduced liver levels of Mcp1 (p = 0.026) and Timp2 (p = 0.007) specifically in the mutant knock-in mice. This may reduce levels of chemokine attracting inflammatory cells and increase the collagenolytic activity during tissue regeneration.

Conclusion

This study provides the first evidence that a Pnpla3 ASO therapy can improve all features of NAFLD, including liver fibrosis, and suppress the expression of a strong innate genetic risk factor, Pnpla3 148M, which may open up a precision medicine approach in NASH.

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ASO-mediated silencing of Pnpla3 reduced liver steatosis specifically in homozygous Pnpla3 148M/M mice fed a high-sucrose diet.

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In mice fed a NASH-inducing diet this treatment reduced liver inflammation and fibrosis specifically in the Pnpla3 148M/M mutant mice.

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This is the first proof of concept of a NASH precision medicine treatment exploiting an innate genetic risk variant for the disease.

Haptoglobin phenotype influences the effectiveness of diet-induced weight loss in middle-age abdominally obese women with metabolic abnormalities

BACKGROUND & AIMS

Haptoglobin (Hp) is associated with risks of obesity and cardiometabolic dysfunction; however, the role of the Hp phenotype in diet-induced weight loss remains to be elucidated. This study investigated whether the Hp phenotype contributes to inter-individual variations in body weight reduction as well as changes in the metabolic profile.

METHODS

Secondary data analysis from a randomized controlled trial. In total, 151 abdominally obese Taiwanese women with ≥2 metabolic components were randomized to each of four dietary programs [calorie restriction (CR), calorie restriction plus fish oil supplementation (CRF), calorie restricted meal replacement (CRMR), and calorie restricted meal replacement with fish oil supplementation (CRMRF)] for 12 weeks. Abdominal obesity was defined as a waist circumference (WC) ≥ 80 cm in women. Hp phenotyping was performed by plasma gel electrophoresis.

RESULTS

The prevalence of the Hp 1-1, 2-1, and 2-2 phenotypes were 12.58%, 41.06% and 46.35%, respectively. The mean age was 50.59 ± 12.22 years, and mean reduction in the percent body weight was 4.7% ± 3.8%. The Hp 1-1 phenotype exhibited significant decreases in the WC, body fat mass, plasma insulin levels, free hemoglobin and homeostatic model assessment of insulin resistance (HOMA-IR) compared to the Hp 2-1 or Hp 2-2 phenotypes after adjusting for the baseline age, WC, metabolic syndrome (MetS), and dietary programs (all adjusted p < 0.05). A greater improvement in the prevalence of central obesity and, to a lesser extent, MetS was also found in women with the Hp 1-1 phenotype.

CONCLUSIONS

Obese women with the Hp 1-1 phenotype might obtain greater benefits in terms of reducing abdominal fat and improving insulin sensitivity in response to hypocaloric diet-induced weight reduction. The findings from this study support potential gene-diet interactions affecting weight loss. This trial was registered at ClinicalTrials.gov as NCT01768169.

CLINICAL TRIAL REGISTRY

This trial was registered at ClinicalTrials.gov as NCT01768169.

Antiobesity Effect of Prebiotic Polyphenol-Rich Grape Seed Flour Supplemented with Probiotic Kefir-Derived Lactic Acid Bacteria

The interaction between prebiotics and probiotics may exert synergistic health benefits. This study investigated the combined effects of polyphenol-rich wine grape seed flour (GSF), a prebiotic, and lactic acid bacteria (LAB) derived from kefir, a probiotic, on obesity-related metabolic disease in high-fat diet (HFD) induced obese (DIO) mice. DIO mice were fed with HFD with 6% microcrystalline cellulose (CON) or HFD supplemented with GSF (5% or 10% GSF), HFD with LAB orally administrated (LAB), or HFD with a combination of GSF and LAB orally administrated (GSF+LAB) for 9 weeks. The vehicle, saline, was also orally administered to the CON and GSF groups. In comparison to CON, all GSF and LAB groups showed a reduction ( P < 0.05) in HF-induced weight gain, liver and adipose tissue weights, plasma lipid concentrations, insulin resistance, and glucose intolerance. The combination of 10% GSF and LAB showed synergistic effects ( P < 0.05) on body weight gain, plasma insulin and total cholesterol concentrations, and cecum propionate contents. Plasma zonulin and cecum propionate concentrations and intestinal FXR gene expression were ( P < 0.05) correlated with body weight gain. A pathway analysis of microarray data of adipose tissue showed that the combination of GSF and LAB affected genes involved in metabolic and immunological diseases, including inflammasome complex assembly ( P < 0.05). In conclusion, a combination of GSF and LAB inhibited HF-induced obesity and inflammation via alterations in intestinal permeability and adipocyte gene expression.

Mild Methylenetetrahydrofolate Reductase Deficiency Alters Inflammatory and Lipid Pathways in Liver

SCOPE

Dietary and genetic folate disturbances can lead to nonalcoholic fatty liver disease (NAFLD). A common variant in methylenetetrahydrofolate reductase (MTHFR 677C→T) causes mild MTHFR deficiency with lower 5-methyltetrahydrofolate for methylation reactions. The goal is to determine whether mild murine MTHFR deficiency contributes to NAFLD-related effects.

METHODS AND RESULTS

Wild-type and Mthfr^+/- mice, a model for the human variant, are fed control (CD) or high-fat (HFAT) diets for 8 weeks. On both diets, MTHFR deficiency results in decreased S-adenosylmethionine, increased S-adenosylhomocysteine, and decreased betaine with reduced methylation capacity, and changes in expression of several inflammatory or anti-inflammatory mediators (Saa1, Apoa1, and Pon1). On CD, MTHFR deficiency leads to microvesicular steatosis with expression changes in lipid regulators Xbp1s and Cyp7a1. The combination of MTHFR deficiency and HFAT exacerbates changes in inflammatory mediators and introduces additional effects on inflammation (Saa2) and lipid metabolism (Nr1h4, Srebf1c, Ppara, and Crot). These effects are consistent with increased expression of pro-inflammatory HDL precursors and greater lipid accumulation. MTHFR deficiency may enhance liver injury through alterations in methylation capacity, inflammatory response, and lipid metabolism.

CONCLUSION

Individuals with the MTHFR variant may be at increased risk for liver disease and related complications, particularly when consuming high-fat diets.

Haptoglobin levels are influenced by Hp1-Hp2 polymorphism, obesity, inflammation, and hypertension in type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is an inflammatory condition associated to obesity and increased oxidative stress. Haptoglobin (Hp) is an acute phase reactant that scavenges extracorpuscular hemoglobin from circulation and prevents heme-iron oxidative damage.

OBJECTIVE

To assess the association between Hp levels and Hp1-Hp2 gene polymorphism and clinical and laboratory parameters in patients with T2DM.

METHODS

The study sample consisted of 102 T2DM patients and 62 controls. Hp plasma levels were measured using an ELISA assay, and Hp genotyping was performed using a specific two-step allelic polymerase chain reaction.

RESULTS

Hp levels were higher in T2DM patients as compared to controls (p=0.005). T2DM patients with high blood pressure had higher Hp levels than patients without this comorbidity (p=0.021). Obese T2DM patients had higher Hp levels as compared to obese controls (p=0.009) and to non-obese T2DM patients (p=0.003). The Hp1-Hp1 genotype was showed to be associated to T2DM according to additive (OR=3.038, 95% CI 1.127-8.192; p=0.036) and dominant model (OR=0.320, 95% CI 0.118-0.839; p=0.010), but Hp2 allele carriers contributed with higher Hp levels in T2DM as compared to controls. Waist circumference (p=0.002), BMI (p=0.001), and IL-6 (p=0.012), and hs-CRP (p=0.001) levels positively correlated with Hp levels in the T2DM group.

CONCLUSION

These results suggest that Hp levels are influenced by Hp1-Hp2 polymorphism, obesity, inflammatory status, and high blood pressure in T2DM.

Type 2 diabetes - An autoinflammatory disease driven by metabolic stress

Type 2 diabetes has traditionally been viewed as a metabolic disorder characterised by chronic high glucose levels, insulin resistance, and declining insulin secretion from the pancreas. Modern lifestyle, with abundant nutrient supply and reduced physical activity, has resulted in dramatic increases in the rates of obesity-associated disease conditions, including diabetes. The associated excess of nutrients induces a state of systemic low-grade chronic inflammation that results from production and secretion of inflammatory mediators from the expanded pool of activated adipocytes. Here, we review the mechanisms by which obesity induces adipose tissue dysregulation, detailing the roles of adipose tissue secreted factors and their action upon other cells and tissues central to glucose homeostasis and type 2 diabetes. Furthermore, given the emerging importance of adipokines, cytokines and chemokines in disease progression, we suggest that type 2 diabetes should now be viewed as an autoinflammatory disease, albeit one that is driven by metabolic dysregulation.

Haptoglobin levels, but not Hp1-Hp2 polymorphism, are associated with polycystic ovary syndrome

PURPOSE

Proteomic studies suggest an association between haptoglobin (Hp) and polycystic ovary syndrome (PCOS). Hp is a classic inflammatory marker and binds to the intravascular hemoglobin, avoiding the oxidative damages that can be caused by free hemoglobin. Inflammation and oxidative stress are important in the pathogenesis of the PCOS, one of the most frequent metabolic diseases in women.

METHODS

To validate these proteomic studies, we developed a controlled cross-sectional study that aimed to evaluate the Hp levels and allelic and genotypic frequencies of Hp1-Hp2 polymorphism in Brazilian women with PCOS. We also investigated the correlation between Hp levels and several important parameters in PCOS as follows: body mass index (BMI), waist circumference (WC), fasting glucose, post-prandial glucose, homeostatic model assessment (HOMA), lipid accumulation product (LAP), C-reactive protein (CRP), and metabolization test of tetrazolium salts (MTTs-serum antioxidant capacity).

RESULTS

Plasma Hp levels were higher in the PCOS group than in controls [8.20 (4.04) g/L; 7.98 (3.31) g/L; p = 0.018]. No significant difference was observed in the frequency of Hp1-Hp2 genotypes under additive, recessive, or dominant model of inheritance between the PCOS and the control groups. Plasma Hp levels did not differ according to the genotype. However, plasma Hp showed a negative correlation with MTT (r = - 0.383; p = 0.028), as well as a positive correlation with CRP (r = 0.361; p = 0.014) in the PCOS group.

CONCLUSION

Hp1-Hp2 polymorphism is not associated with PCOS but plasma Hp could be a potential biomarker for PCOS and its complications.

Up-Regulation of Antioxidant Proteins in the Plasma Proteome during Saturation Diving: Unique Coincidence under Hypobaric Hypoxia

Saturation diving (SD) is one of the safest techniques for tolerating hyperbaric conditions for long durations. However, the changes in the human plasma protein profile that occur during SD are unknown. To identify differential protein expression during or after SD, 65 blood samples from 15 healthy Japanese men trained in SD were analyzed by two-dimensional fluorescence difference gel electrophoresis. The expression of two proteins, one 32.4 kDa with an isoelectric point (pI) of 5.8 and the other 44.8 kDa with pI 4.0, were elevated during SD to 60, 100, and 200 meters sea water (msw). The expression of these proteins returned to pre-diving level when the SD training was completed. The two proteins were identified using in-gel digestion and mass spectrometric analysis; the 32.4 kDa protein was transthyretin and the 44.8 kDa protein was alpha-1-acid glycoprotein 1. Oxidation was detected at methionine 13 of transthyretin and at methionine 129 of alpha-1-acid glycoprotein 1 by tandem mass spectrometry. Moreover, haptoglobin was up-regulated during the decompression phase of 200 msw. These plasma proteins up-regulated during SD have a common function as anti-oxidants. This suggests that by coordinating their biological effects, these proteins activate a defense mechanism to counteract the effects of hyperbaric-hyperoxic conditions during SD.

The Multifaceted Haptoglobin in the Context of Adipose Tissue and Metabolism

Obesity is a low chronic inflammatory state because several inflammatory factors are increased in obese subjects, this having important implications for the onset of obesity-associated complications. The source of most of these inflammatory molecules is white adipose tissue (WAT), which upon excessive weight gain, becomes infiltrated with macrophages and lymphocytes and undergoes important changes in its gene expression. Haptoglobin (Hp), a typical marker of inflammation in clinical practice, main carrier of free hemoglobin, and long known to be part of the hepatic acute phase response, perfectly sits in the intersection between obesity and inflammation: it is expressed by adipocytes and its abundance in WAT and in plasma positively relates to the degree of adiposity. In the present review, we will analyze causes and consequences of Hp expression and regulation in WAT and how these relate to the obesity/inflammation paradigm and comorbidities.

Haptoglobin is required to prevent oxidative stress and muscle atrophy

BACKGROUND

Oxidative stress (OS) plays a major role on tissue function. Several catabolic or stress conditions exacerbate OS, inducing organ deterioration. Haptoglobin (Hp) is a circulating acute phase protein, produced by liver and adipose tissue, and has an important anti-oxidant function. Hp is induced in pro-oxidative conditions such as systemic inflammation or obesity. The role of systemic factors that modulate oxidative stress inside muscle cells is still poorly investigated.

RESULTS

We used Hp knockout mice (Hp-/-) to determine the role of this protein and therefore, of systemic OS in maintenance of muscle mass and function. Absence of Hp caused muscle atrophy and weakness due to activation of an atrophy program. When animals were stressed by acute exercise or by high fat diet (HFD), OS, muscle atrophy and force drop were exacerbated in Hp-/-. Depending from the stress condition, autophagy-lysosome and ubiquitin-proteasome systems were differently induced.

CONCLUSIONS

Hp is required to prevent OS and the activation of pathways leading to muscle atrophy and weakness in normal condition and upon metabolic challenges.

Caspase induction and BCL2 inhibition in human adipose tissue: a potential relationship with insulin signaling alteration

OBJECTIVE

Cell death determines the onset of obesity and associated insulin resistance. Here, we analyze the relationship among obesity, adipose tissue apoptosis, and insulin signaling.

RESEARCH DESIGN AND METHODS

The expression levels of initiator (CASP8/9) and effector (CASP3/7) caspases as well as antiapoptotic B-cell lymphoma (BCL)2 and inflammatory markers were assessed in visceral (VAT) and subcutaneous (SAT) adipose tissue from patients with different degrees of obesity and without insulin resistance or diabetes. Adipose tissue explants from lean subjects were cultured with TNF-α or IL-6, and the expression of apoptotic and insulin signaling components was analyzed and compared with basal expression levels in morbidly obese subjects.

RESULTS

SAT and VAT exhibited increased CASP3/7 and CASP8/9 expression levels and decreased BCL2 expression with BMI increase. These changes were accompanied by increased inflammatory cytokine mRNA levels and macrophage infiltration markers. In obese subjects, CASP3/7 activation and BCL2 downregulation correlated with the IRS-1/2-expression levels. Expression levels of caspases, BCL2, p21, p53, IRS-1/2, GLUT4, protein tyrosine phosphatase 1B, and leukocyte antigen-related phosphatase in TNF-α- or IL-6-treated explants from lean subjects were comparable with those found in adipose tissue samples from morbidly obese subjects. These insulin component expression levels were reverted with CASP3/7 inhibition in these TNF-α- or IL-6-treated explants.

CONCLUSIONS

Body fat mass increase is associated with CASP3/7 and BCL2 expression in adipose tissue. Moreover, this proapoptotic state correlated with insulin signaling, suggesting its potential contribution to the development of insulin resistance.

Effect of Voluntary Exercise on Genetically ObeseCpefat/fatMice: Quantitative Proteomics of Serum

OBJECTIVE

To compare the effect of voluntary exercise on body weight, food consumption, and levels of serum proteins between wild-type and carboxypeptidase E-deficient (Cpefat/fat) mice.

RESEARCH METHODS AND PROCEDURES

Study 1 consisted of three groups of female mice: Cpefat/fat mice with continuous access to exercise wheels for 3 weeks (n = 4); wild-type C57BKS mice with access to exercise wheels for 3 weeks (n = 4); and sedentary Cpefat/fat mice (n = 3). Activity, body weight, and food consumption were monitored for this period and a subsequent 9-week period without exercise wheels. Study 2 consisted of four groups of male mice (n = 6 to 7 each): Cpefat/fat mice with exercise wheels, wild-type mice with exercise wheels, and Cpefat/fat and wild-type mice without exercise wheels. Body weight and food consumption were measured over 4 weeks. Sera were collected, and the protein profile was determined by 2-dimensional gel electrophoresis and mass spectrometry.

RESULTS

Cpefat/fat mice were moderately hyperphagic but lost weight during the initial exercise period because of greater energy expenditure. The effect of exercise was temporary, and the mice gained weight after the second week. Several serum proteins were found to be altered by exercise: haptoglobin was decreased by exercise in Cpefat/fat mice, and several kallikreins were increased by exercise in wild-type mice.

DISCUSSION

The access to exercise wheels provided an initial weight loss in Cpefat/fat mice, but this effect was offset by elevated food consumption. The serum proteomics results indicated that Cpefat/fat and wild-type mice differed in their response to exercise.

Adipose Gene Expression Patterns of Weight Gain Suggest Counteracting Steroid Hormone Synthesis

OBJECTIVE

To identify early molecular changes in weight gain, using analysis of gene expression changes in adipose tissue of mice fed well-defined humanized (Western) high-fat and low-fat (control) diets during a short (3- to 5-week) time interval.

RESEARCH METHODS AND PROCEDURES

An adipose-enriched cDNA microarray was constructed and used for the expression analyses of visceral adipose tissues of wildtype young adult C57BL/6J male mice on different diets.

RESULTS

Mice on a high-fat diet had significantly higher body weight (at most, 9.6% greater) and adipose tissue weights compared with mice on a control diet. Gene expression analyses revealed 31 transcripts significantly differentially expressed in visceral adipose tissue between the diet groups. Most of these genes were expressed more on the high-fat diet. They mainly encode proteins involved in cellular structure (e.g., myosin, procollagen, vimentin) and lipid metabolism (e.g., leptin, lipoprotein lipase, carbonic anhydrase 3). This increase in gene expression was accompanied by a decrease in oxidative phosphorylation and carbohydrate metabolism (ATP citrate lyase). Importantly, genes belonging to steroid hormone biosynthesis (3beta-hydroxysteroid dehydrogenase-1, cholesterol side-chain cleavage cytochrome P450, and steroid-11beta-hydroxylase) were all expressed less in mice on a high-fat diet.

DISCUSSION

A short time period of 3 to 5 weeks of high-fat feeding altered gene expression patterns in visceral adipose tissue in male mice. Gene expression changes indicate initiation of adipose tissue enlargement and the down-regulation of adipose steroid hormone biosynthesis. The latter suggests a mechanism by which initial progression toward weight gain is counteracted.

Haptoglobin deficiency determines changes in adipocyte size and adipogenesis

Haptoglobin (Hp) is an inflammatory and adiposity marker, its expression during obesity being specifically induced in the white adipose tissue (WAT). We previously reported that when challenged with a high fat diet (HFD) Hp^−/− mice are partially protected from the onset of insulin resistance and hepatosteatosis. The aim of the present study was to get further insights into Hp function in WAT. To this end, we performed histological and gene expression analysis of the Hp^−/− WAT, both in standard and obesity conditions, and investigated how Hp deficiency impacts adipogenesis and WAT development.

The average size and percentage of very large adipocytes were respectively smaller and reduced in HFD Hp^−/− mice as compared with HFD WT. The expression of perilipin, HSL and angiogenesis related markers were increased in HFD Hp^−/− mice. Lean adult Hp^−/− showed significantly larger adipocytes and lower subcutaneous WAT expression of aP2 and LPL with respect to WT. Hp^−/− young mice (P30) were characterized by larger adipocyte size and lower expression of adipocyte and adipogenesis markers. Comparison of adipocyte size distribution between young and adult mice revealed attenuated changes in Hp^−/− mice compared with WT. Mouse embryonic fibroblasts from Hp^−/− mice were less capable of accumulating triglycerides and exhibited lower expression of PPARγ, aP2, FAS, LPL and Leptin.

In conclusion, Hp deficiency tends to blunt the effect of age and diet on the size of adipocytes, which show less susceptibility to develop hypertrophy during obesity and a reduced adipogenic/hyperplastic potential during youth. In addition, Hp deficiency impacts negatively on adipogenesis.

Inter-organ proteomic analysis reveals insights into the molecular mechanisms underlying the anti-diabetic effects of cis-9, trans-11-conjugated linoleic acid in ob/ob mice

cis-9, trans-11-Conjugated linoleic acid (c9 t11 CLA) exerts anti-diabetic effects by improving systemic insulin sensitivity and inflammation. Levels of CLA in beef can be increased by feeding cattle on pasture. This study aimed to explore the efficacy of a CLA-rich diet (0.6% w/w c9 t11 CLA), presented as beef enriched with CLA or beef supplemented with synthetic CLA (c9 t11 CLA), for 28 days on molecular biomarkers of the metabolic syndrome, and adipose, hepatic, and skeletal muscle proteome in male ob/ob mice. Despite equal weight gain, CLA-fed mice had lower plasma glucose, insulin, non-esterified fatty acid, triacylglycerol and interleukin-6, and higher adiponectin concentrations than controls. c9 t11 CLA induced differential regulation of redox status across all tissues, and decreased hepatic and muscle endoplasmic reticulum stress. CLA also modulated mechanistic links between the actin cytoskeleton, insulin signalling, glucose transport and inflammation in the adipose tissue. In the liver and muscle, c9 t11 CLA improved metabolic flexibility through co-ordination between carbohydrate and energy metabolism. c9 t11 CLA may ameliorate systemic insulin sensitivity in obesity-induced diabetes by altering cellular stress and redox status, and modulating nutrient handling in key insulin-sensitive tissues through complex biochemical interplay among representative proteomic signatures.

PGRN is a key adipokine mediating high fat diet-induced insulin resistance and obesity through IL-6 in adipose tissue

Adipose tissue secretes adipokines that mediate insulin resistance, a characteristic feature of obesity and type 2 diabetes. By differential proteome analysis of cellular models of insulin resistance, we identified progranulin (PGRN) as an adipokine induced by TNF-α and dexamethasone. PGRN in blood and adipose tissues was markedly increased in obese mouse models and was normalized with treatment of pioglitazone, an insulin-sensitizing agent. Ablation of PGRN (Grn(-/-)) prevented mice from high fat diet (HFD)-induced insulin resistance, adipocyte hypertrophy, and obesity. Grn deficiency blocked elevation of IL-6, an inflammatory cytokine, induced by HFD in blood and adipose tissues. Insulin resistance induced by chronic administration of PGRN was suppressed by neutralizing IL-6 in vivo. Thus, PGRN is a key adipokine that mediates HFD-induced insulin resistance and obesity through production of IL-6 in adipose tissue, and may be a promising therapeutic target for obesity.

Obesity-associated hepatosteatosis and impairment of glucose homeostasis are attenuated by haptoglobin deficiency

OBJECTIVE

Haptoglobin (Hp) is upregulated in both inflammation and obesity. The low chronic inflammatory state, caused by massive adipose tissue macrophage (ATM) infiltration found in obesity, and low adiponectin have been implicated in the development of insulin resistance and hepatosteatosis. The aim of this work was to investigate whether and how Hp interferes with the onset of obesity-associated complications.

RESEARCH DESIGN AND METHODS

Hp-null (Hp(-/-)) and wild-type (WT) mice were metabolically profiled under chow-food diet (CFD) and high-fat diet (HFD) feeding by assessing physical parameters, glucose tolerance, insulin sensitivity, insulin response to glucose load, liver triglyceride content, plasma levels of leptin, insulin, glucose, and adiponectin. ATM content was evaluated by using immunohistochemistry (anti-F4/80 antibody). Adiponectin expression was measured in Hp-treated, cultured 3T3-L1 and human adipocytes.

RESULTS

No genotype-related difference was found in CFD animals. HFD-Hp(-/-) mice revealed significantly higher glucose tolerance, insulin sensitivity, glucose-stimulated insulin secretion, and adiponectin expression and reduced hepatomegaly/steatosis compared with HFD-WT mice. White adipose tissue (WAT) of HFD-Hp(-/-) mice showed higher activation of insulin signaling cascade, lower ATM, and higher adiponectin expression. Hp was able to inhibit adiponectin expression in cultured adipocytes.

CONCLUSIONS

We demonstrated that in the absence of Hp, obesity-associated insulin resistance and hepatosteatosis are attenuated, which is associated with reduced ATM content, increased plasma adiponectin, and higher WAT insulin sensitivity.

Haptoglobin polymorphism and association with complications in ghanaian type 2 diabetic patients

There is scanty information on the role of genetic factors, especially those relating to haptoglobin (Hp) phenotypes in the expression of complications among diabetes mellitus patients in Ghana. In this study, we investigated whether there is any association between Hp phenotypes and diabetic complications and to determine if association of the Hp phenotypes with diabetic complications in Ghanaian diabetics differ from those in Caucasians. A total of 398 participants were randomly recruited into the study. These comprised diabetic patients numbering 290 attending a diabetes Clinic in Ghana and 108 non-diabetic controls from the same community. Analyses of the results indicate that most of the diabetics with complications were of the Hp 2-2 (35%) and Hp 2-1 (23.9%) phenotypes. Fewer diabetics were found to be of the Hp 2-1 M phenotype. The controls were mostly of Hp 1-1 and Hp 2-1 M phenotypes. The odds ratio of having complications in a diabetic with an Hp 2-2 phenotype was 18.27 times greater than that for Hp 0-0. Hp 2-2 phenotype with its poor antioxidant activity may therefore be a useful predictor for the propensity of an individual to develop diabetes complications.

Are interleukin-6, body mass index and atopy crucial in infantile intussusception?

OBJECTIVE

To determine the role of inflammation related to body mass index (BMI) and atopy in the etiology of idiopathic intussusception (IS) which is seen more frequently in obese children and which is considered to increase in the allergy season.

METHODS

The study comprised a study group consisting of 22 infants with IS and a control group consisting of 20 healthy infants with age and BMI matched. In both groups, gender, weight, height, month of birth, month of admittance (allergy season) of each infant were recorded. Information regarding whether or not the child had any skin rash, atopy, oral allergy syndrome, and whether or not the patient had been fed cow's milk and breast milk was recorded. Hemoglobin (Hb) levels, white blood cell (WBC) and eosinophil counts, interleukin-6 (IL-6) levels and allergy panel were studied in all patients. Additionally, cross reactive protein (CRP) and blood urea nitrogen (BUN) levels were determined in the study group. During statistical comparison p < 0.05 was considered statistically significant.

RESULTS

Mean IL-6 levels in the control and study groups were 1.59 ± 0.15 pg/ml and 4.12 ± 5.04 pg/ml, respectively. IL-6 levels were statistically different between each groups and between cases with barium reduction and cases reduced manually by laparotomy within the study group. Both groups were similar statistically with regard to the others parameters. No atopy was detected by allergy panel. When binary logistic regression analysis with the cut-off value of IL-6 set as 1.6 pg/ml was applied to all data, statistically significant values were obtained only when the case was in the study group and when CRP levels were increased (p = 0.05 and p = 0.001, respectively).

CONCLUSIONS

We demonstrated that IL-6 levels are increased in the study group, especially in the operated patients, however, that high BMI and atopy have no effects on this fact and that atopy is not associated with IS in the clinical study.

Mechanisms regulating repression of haptoglobin production by peroxisome proliferator-activated receptor-gamma ligands in adipocytes

Obesity leads to inflammation of white adipose tissue involving enhanced secretion of cytokines and acute-phase proteins in response in part to the accumulation of excess lipids in adipocytes. Haptoglobin is an acute-phase reactant secreted by white adipose tissue and induced by inflammatory cytokines such as TNFalpha. In this study, we investigated the mechanisms regulating haptoglobin expression in adipocytes. Peroxisome proliferator-activated receptor (PPAR)-gamma agonists such as thiazolidinediones (TZDs) as well as non-TZD ligands can repress in vitro and in vivo haptoglobin expression in adipocytes and also prevent its induction by TNFalpha. This action requires direct involvement of PPAR gamma in regulating haptoglobin gene transcription because mutation of critical amino acids within helix 7 of the ligand-binding domain of PPAR gamma prevents repression of the haptoglobin gene by the synthetic ligands. Chromatin immunoprecipitation analysis shows active binding of PPAR gamma to a distal region of the haptoglobin promoter, which contains putative PPAR gamma binding sites. Additionally, PPAR gamma induces transcription of a luciferase reporter gene when driven by the distal promoter region of the haptoglobin gene, and TZD treatment significantly reduces the extent of this induction. Furthermore, the mutated PPAR gamma is incapable of enhancing luciferase activity in these in vitro reporter gene assays. In contrast to other adipokines repressed by TZDs such as resistin and chemerin, repression of haptoglobin does not require either CCAAT/enhancer-binding protein C/EBP alpha or the corepressors C-terminal binding protein 1 or 2. These data are consistent with a model in which synthetic PPAR gamma ligands selectively activate PPAR gamma bound to the haptoglobin gene promoter to arrest haptoglobin gene transcription.

The obesity and inflammatory marker haptoglobin attracts monocytes via interaction with chemokine (C-C motif) receptor 2 (CCR2)

Background

Obesity is a chronic low inflammatory state. In the obesity condition the white adipose tissue (WAT) is massively infiltrated with monocytes/macrophages, and the nature of the signals recruiting these inflammatory cells has yet to be fully elucidated. Haptoglobin (Hp) is an inflammatory marker and its expression is induced in the WAT of obese subjects. In an effort to elucidate the biological significance of Hp presence in the WAT and of its upregulation in obesity we formulated the hypothesis that Hp may serve as a macrophage chemoattractant.

Results

We demonstrated by chemotaxis assay that Hp is able to attract chemokine (C-C motif) receptor 2 (CCR2)-transfected pre-B lymphocytes and monocytes in a dose-dependent manner. Moreover, Hp-mediated migration of monocytes is impaired by CCR2-specific inhibition or previous cell exposure to monocyte chemoattractant protein 1 (MCP1) (also known as CCR2 ligand or chemokine (C-C motif) ligand 2 (CCL2)). Downstream effects of Hp/CCR2 interaction were also investigated: flow cytometry proved that monocytes treated with Hp show reduced CCR2 expression on their surface; Hp interaction induces calcium release that is reduced upon pretreatment with CCR2 antagonist; extracellular signal-regulated kinase (ERK)1/2, a signal transducer activated by CCR2, is phosphorylated following Hp treatment and this phosphorylation is reduced when cells are pretreated with a specific CCR2 inhibitor. Consistently, blocking the ERK1/2 pathway with U0126, the selective inhibitor of the ERK upstream mitogen-activated protein (MAP)-ERK kinase (MEK), results in a dramatic reduction (by almost 100%) of the capability of Hp to induce monocyte migration.

Conclusions

Our data show that Hp is a novel monocyte chemoattractant and that its chemotactic potential is mediated, at least in part. by its interaction with CCR2.

Improvement in insulin resistance and reduction in plasma inflammatory adipokines after weight loss in obese dogs

Obesity is now a major disease of dogs, predisposing to numerous disorders including diabetes mellitus. Adipocytes are active endocrine cells, and human obesity is characterized by derangements in inflammatory adipokine production. However, it is unclear as to whether similar changes occur in dogs. The purpose of the current study was to assess insulin sensitivity and inflammatory adipokine profiles in dogs with naturally occurring obesity and to investigate the effect of subsequent weight loss. Twenty-six overweight dogs were studied, representing a range of breeds and both sexes. All dogs underwent a weight loss program involving diet and exercise. Body fat mass was measured by dual-energy x-ray absorptiometry; plasma concentrations of insulin, glucose, and a panel of inflammatory adipokines (including acute-phase proteins, cytokines, and chemokines) were also analyzed. Body fat mass before weight loss was positively correlated with both plasma insulin concentrations (Kendall tau=0.30, P=0.044) and insulin:glucose ratio (Kendall tau=0.36, P=0.022), and both decreased after weight loss (P=0.0037 and 0.0063, respectively). Weight loss also led to notable decreases in plasma tumor necrosis factor-alpha (TNF-alpha), haptoglobin, and C-reactive protein concentrations (P<0.05 for all), suggesting improvement of a subclinical inflammatory state associated with obesity. This study has demonstrated that in obese dogs, insulin resistance correlates with degree of adiposity, and weight loss improves insulin sensitivity. Concurrent decreases in TNF-alpha and adipose tissue mass suggest that in dogs, as in humans, this adipokine may be implicated in the insulin resistance of obesity.

Obesidade e adipocinas inflamatórias: implicações práticas para a prescrição de exercício

A obesidade é uma doença complexa de etiologia multifacetada, com sua própria fisiopatologia, comorbidades e capacidades desabilitantes. Aceitar a obesidade como uma doença é fundamental para o seu tratamento. Atualmente, o tecido adiposo é um dos principais focos das pesquisas em obesidade, devido a uma revolução no entendimento da função biológica desse tecido desde a última década. Já está muito claro que o tecido adiposo branco secreta múltiplos peptídeos bioativos, denominados adipocinas (proteínas sintetizadas e secretadas pelo tecido adiposo). Dessa forma, o objetivo deste trabalho de revisão foi investigar a relação entre obesidade e adipocinas inflamatórias, buscando discutir o papel do exercício físico no tratamento dessa patologia. Os resultados demonstram que uma das mais importantes descobertas das pesquisas recentes em obesidade é o conceito de que ela é caracterizada por uma inflamação crônica. Dentre todas as adipocinas, sem dúvida, a IL-6, o TNF-α, a leptina (pró-inflamatórias) e a adiponectina (anti-inflamatória) vêm recebendo atenção especial da literatura especializada. O aumento da concentração dessas adipocinas promove grande impacto em diversas funções corporais que estão fortemente correlacionadas com doenças cardiovasculares. Uma vez que a obesidade é considerada uma doença inflamatória e o exercício físico modula de forma direta tais processos, é essencial que tenhamos como um dos objetivos principais de nossos programas de exercícios físicos a melhora da resposta inflamatória de obesos.

Metabolism and secretory function of white adipose tissue: effect of dietary fat

Approximately 40% of the total energy consumed by western populations is represented by lipids, most of them being ingested as triacylglycerols and phospholipids. The focus of this review is to analyze the effect of the type of dietary fat on white adipose tissue metabolism and secretory function, particularly on haptoglobin, TNF-α, plasminogen activator inhibitor-1 and adiponectin secretion. Previous studies have demonstrated that the duration of the exposure to the high-fat feeding, amount of fatty acid present in the diet and the type of fatty acid may or may not have a significant effect on adipose tissue metabolism. However, the long-term or short-term high fat diets, especially rich in saturated fatty acids, probably by activation of toll-like receptors, stimulated the expression of proinflammatory adipokines and inhibited adiponectin expression. Further studies are needed to investigate the cellular mechanisms by which dietary fatty acids affect white adipose tissue metabolism and secretory functions.

Systems biology and its potential role in radiobiology

About a century ago, Conrad Röentgen discovered X-rays, and Henri Becquerel discovered a new phenomenon, which Marie and Pierre Curie later coined as radio-activity. Since their seminal work, we have learned much about the physical properties of radiation and its effects on living matter. Alas, the more we discover, the more we appreciate the complexity of the biological processes that are triggered by radiation exposure and eventually lead (or do not lead) to disease. Equipped with modern biological methods of high-throughput experimentation, imaging, and vastly increased computational prowess, we are now entering an era where we can piece some of the multifold aspects of radiation exposure and its sequelae together, and develop a more systemic understanding of radiogenic effects such as radio-carcinogenesis than has been possible in the past. It is evident from the complexity of even the known processes that such an understanding can only be gained if it is supported by mathematical models. At this point, the construction of comprehensive models is hampered both by technical inadequacies and a paucity of appropriate data. Nonetheless, some initial steps have been taken already and the generally increased interest in systems biology may be expected to speed up future progress. In this context, we discuss in this article examples of relatively small, yet very useful models that elucidate selected aspects of the effects of exposure to ionizing radiation and may shine a light on the path before us.

Haptoglobin polymorphism and diabetic retinopathy in Brazilian patients

Haptoglobin (Hp) is an acute phase protein with antioxidant and immunomodulatory properties. Three main genotypes/phenotypes (Hp1-1, Hp2-1 and Hp2-2) show distinct efficiencies in these activities and have been associated with susceptibility and outcome in several diseases, including diabetes mellitus (DM). It has been suggested that Hp polymorphism may influence the development of retinopathy, an important microvascular complication in DM. In order to investigate this association in a Brazilian population, we determined the Hp genotypes of 317 diabetic patients with at least 10 years of disease. The patients were classified as DM-type 1 and 2, with and without diabetic retinopathy (DR). The Hp genotype frequencies of the different patient groups and of a control group consisting of 142 healthy individuals who had previously been studied were compared. No significant differences were observed for the three Hp genotypes. Hemoglobin A1c levels, systolic blood pressure (SBP), diastolic blood pressure (DBP) and duration of diabetes, which are potential risk factors for DR, were also compared. Again no significant differences were observed for the three Hp genotypes. Thus, we conclude that this polymorphism is not associated with the presence of DR in the Brazilian population studied here.

Moving toward a system genetics view of disease

Testing hundreds of thousands of DNA markers in human, mouse, and other species for association to complex traits like disease is now a reality. However, information on how variations in DNA impact complex physiologic processes flows through transcriptional and other molecular networks. In other words, DNA variations impact complex diseases through the perturbations they cause to transcriptional and other biological networks, and these molecular phenotypes are intermediate to clinically defined disease. Because it is also now possible to monitor transcript levels in a comprehensive fashion, integrating DNA variation, transcription, and phenotypic data has the potential to enhance identification of the associations between DNA variation and diseases like obesity and diabetes, as well as characterize those parts of the molecular networks that drive these diseases. Toward that end, we review methods for integrating expression quantitative trait loci (eQTLs), gene expression, and clinical data to infer causal relationships among gene expression traits and between expression and clinical traits. We further describe methods to integrate these data in a more comprehensive manner by constructing coexpression gene networks that leverage pairwise gene interaction data to represent more general relationships. To infer gene networks that capture causal information, we describe a Bayesian algorithm that further integrates eQTLs, expression, and clinical phenotype data to reconstruct whole-gene networks capable of representing causal relationships among genes and traits in the network. These emerging network approaches, aimed at processing high-dimensional biological data by integrating data from multiple sources, represent some of the first steps in statistical genetics to identify multiple genetic perturbations that alter the states of molecular networks and that in turn push systems into disease states. Evolving statistical procedures that operate on networks will be critical to extracting information related to complex phenotypes like disease, as research goes beyond a single-gene focus. The early successes achieved with the methods described herein suggest that these more integrative genomics approaches to dissecting disease traits will significantly enhance the identification of key drivers of disease beyond what could be achieved by genetic association studies alone.

Haptoglobin serum levels are independently associated with insulinemia in overweight and obese women

BACKGROUND

Obesity is associated with a chronic low-grade inflammatory condition. Haptoglobin is a glycoprotein involved in the acute-phase response to inflammation, and it is increased in obese subjects. The possibility that hyperinsulinemia and/or insulin resistance may directly increase haptoglobin levels has never been tested. The aim of this study was to investigate the associations of haptoglobin serum levels with anthropometric parameters, insulin levels, insulin resistance and related metabolic variables in overweight and obese women.

PATIENTS AND METHODS

This is a cross-sectional study of 194 non-diabetic overweight and obese subjects, aged 18-68 yr. Measurements included body mass index (BMI), central fat accumulation [evaluated by waist circumference (WC)], systolic and diastolic blood pressure, and fasting concentrations of haptoglobin, insulin, glucose, lipids (triglycerides, total cholesterol, and HDL-cholesterol), and insulin resistance as estimated by the homeostasis model assessment (HOMAIR).

RESULTS

Haptoglobin serum levels showed a positive association with BMI (p<0.001), WC (p<0.001), HOMAIR (p<0.001), and fasting insulin (p<0.001), triglyceride (p<0.001) and glucose (p<0.05) blood levels. However, only insulin maintained a significant independent association with haptoglobin (p<0.001) when a multiple regression analysis was performed and age, BMI (or WC), blood pressure levels, HOMAIR, and fasting insulin, glucose, and lipid blood concentrations were entered as independent variables.

CONCLUSIONS

Higher haptoglobin serum levels seem to be a strong marker of hyperinsulinemia, independently of BMI, body fat distribution, insulin resistance and related parameters.

Dietary conjugated linoleic acid preserves pancreatic function and reduces inflammatory markers in obese, insulin-resistant rats

Pancreatic preservation is an important part of diabetes management that may occur with improved peripheral insulin sensitivity and attenuated low-grade adipose tissue inflammation. The objective of the current study was to determine the response of obese, insulin-resistant fa/fa Zucker rats vs lean controls to dietary conjugated linoleic acid (CLA) supplementation with respect to pancreatic islet size, insulin resistance, and markers of inflammation and adipose glucose uptake. Six-week-old fa/fa and lean Zucker rats (n = 20 per genotype) were fed either a 1.5% CLA mixture or control diet for 8 weeks. Oral glucose tolerance testing was conducted at 7.5 weeks. Fasting serum haptoglobin, insulin, and C-peptide were assayed, and select messenger RNA (mRNA) and protein markers of inflammation and glucose metabolism were measured in adipose and liver tissues. CLA-fed fa/fa Zucker rats had smaller islet cell size, improved oral glucose tolerance and insulinemia, and attenuated serum haptoglobin levels compared with control-fed fa/fa Zucker rats, despite no differences in body weight and a slightly higher visceral adipose mass. CLA did not alter insulin sensitivity or islet size in lean Zucker rats. The CLA-fed fa/fa rats also had greater adipose glucose transporter-4 mRNA and less adipose tumor necrosis factor alpha mRNA and protein compared with control-fed fa/fa rats. In contrast, other markers of inflammation and glucose metabolism including adipose macrophage inflammatory factor, macrophage inflammatory protein-2, and liver pyruvate carboxylase and pyruvate dehydrogenase kinase 4 were not significantly changed. These results suggest that CLA supplementation preserved pancreatic function in conjunction with improved peripheral glucose use and reduced inflammation in fa/fa Zucker rats.