Postprandial inflammatory responses after oral glucose, lipid and protein challenges: Influence of obesity, sex and polycystic ovary syndrome.

BACKGROUND & AIMS: Most evidence linking the polycystic ovary syndrome (PCOS) with chronic low-grade inflammation has been obtained in the fasting state. We have studied the postprandial inflammatory response to oral glucose, lipid and protein challenges and the possible influences of obesity, sex and PCOS on these responses. METHODS: On alternate days, we submitted 17 women with PCOS (9 non-obese, 8 obese), 17 control women (9 non-obese, 8 obese) and 19 control men (10 non-obese, 9 obese) to isocaloric (300 Kcal) oral macronutrient loads. We assayed serum for TNF-α, IL-6, IL-18, IL-10, pentraxin-3 and galectin-3 concentrations and leukocytes for expression of TNF, IL6, IL10 and their receptors TNFRSF1B, IL6R and IL10RA. RESULTS: Circulating IL-6 levels decreased after glucose and protein ingestion but slightly increased after oral lipid intake. Leukocyte IL6 expression did not change after the ingestion of any macronutrient yet IL6R expression increased during all macronutrient challenges, the largest increase being observed after glucose ingestion. Serum TNF-α similarly decreased during either macronutrient load, whereas TNF expression increased after macronutrient ingestion, the highest increase observed after oral glucose. TNFRSF1B expression also increased after glucose intake but not after lipid or protein ingestion. No global effect of obesity or group on postprandial circulating IL-6, TNF-α, or IL6, IL6R, TNF and TNFRSF1B expression was found. Circulating IL-18 concentrations decreased during all oral challenges, whereas in case of galectin-3 and pentraxin-3 only the protein load caused a reduction in its concentrations. Of the genes studied here, IL10 showed the largest increase in expression throughout all the postprandial curves, particularly after glucose. Obesity blunted the increase in IL10 expression. IL10RA expression decreased after glucose ingestion but remained unchanged during lipid and protein loads. CONCLUSIONS: Glucose ingestion, as opposed to lipid and protein intake, results into the largest increase in leukocyte gene expression of inflammatory mediators. The expression of the anti-inflammatory cytokine IL10 was the largest observed here, suggesting a compensatory mechanisms against postprandial inflammation that may be blunted in obesity. However, these responses did not translate into the circulating concentrations of these inflammatory mediators during the immediate postprandial phase.

Plasma thiobarbituric acid reactive substances (TBARS) in young adults: Obesity increases fasting levels only in men whereas glucose ingestion, and not protein or lipid intake, increases postprandial concentrations regardless of sex and obesity.

SCOPE: Oxidative stress and damage participate in the pathophysiology of obesity and its metabolic complications. We studied the influence of sex, obesity, and ingestion of different macronutrients on fasting and postprandial thiobarbituric acid reactive substances (TBARS), which can be considered as an index of lipid peroxidation and oxidative damage. METHODS AND RESULTS: We studied 19 men and 17 women, out of whom nine men and eight women had obesity. We collected blood samples in the fasting state and, on alternate days, following the ingestion of 300 kcal in the form of glucose, lipids, or proteins. Fasting TBARS concentrations correlated with waist circumference and were increased in obese men compared with nonobese men. This increase was not, however, observed in women. TBARS concentrations showed a marked increase following the ingestion of glucose in parallel to the increase in plasma glucose when considering all subjects as a whole, but did not increase after the oral intake of lipids and proteins. CONCLUSION: Plasma TBARS concentrations are increased in the fasting state only in obese men in association with abdominal adiposity, and increases markedly after the ingestion of glucose, but not after oral intake of lipids and proteins, regardless of sex and obesity.

Effects of glucose ingestion on circulating inflammatory mediators: Influence of sex and weight excess.

BACKGROUND & AIMS: Low-grade chronic inflammation is involved in the pathophysiology of obesity. However, little is known about the influence of sex and sex hormones on surrogate inflammatory markers and mediators, particularly after glucose ingestion. DESIGN: Observational study. METHODS: We measured the circulating concentrations of interleukin-6, interleukin-18, macrophage migration inhibitory factor, matrix metallopeptidase-9, monocyte chemotactic protein-1 and pentraxin-3, in the fasting state and during a 75 g oral glucose tolerance test, in 24 women and 25 men. Eleven men and 11 women were lean whereas 14 men and 13 women had weight excess. RESULTS: Anti-inflammatory cytokines (interleukin-6 and interleukin-18) were increased in the fasting state and/or decreased in some women during the oral glucose tolerance test, as opposed to inflammatory mediators such as macrophage migration inhibitory factor and matrix metallopeptidase-9 that increased during the oral glucose tolerance test especially in subjects with weight excess. Body mass index and waist circumference were the main determinants of these changes. Fasting pentraxin-3 levels were especially increased in lean women in parallel to a decrease in free testosterone levels, and decreased during the oral glucose tolerance test as opposed to the increase in insulin concentrations. CONCLUSIONS: The circulating concentrations of markers of low-grade chronic inflammation in young healthy adults are not only influenced by obesity but also by abdominal adiposity, fasting and glucose ingestion and, in some cases, by sex and sex hormones. These influences should be considered when these markers are used as surrogate markers of the inflammatory milieu associated with obesity.

Serum Bioavailable Vitamin D Concentrations and Bone Mineral Density in Women After Obesity Surgery.

INTRODUCTION: Low bone mass after obesity surgery may arise as a consequence of chronic malabsorption of calcium and vitamin D. However, we have not found any role of serum 25-hydroxyvitamin D or of polymorphisms in the vitamin D receptor gene in previous studies. PURPOSE: To investigate the circulating bioavailable 25-hydroxyvitamin D in women after bariatric procedures and its association with bone mass. PATIENTS AND METHODS: The study consisted of 91 women on follow-up for 7 ± 2 years after bariatric surgery. We measured bone mineral density (BMD), serum parathormone (PTH), 25-hydroxyvitamin D, and vitamin D binding protein (VDBP). All patients were genotyped for two variants in the coding region of VDBP (rs4588 and rs7041). Bioavailable 25-hydroxyvitamin D was calculated in double homozygotes. RESULTS: We found a negative correlation between bioavailable 25-hydroxyvitamin D and PTH (r = -0.373, P = 0.018), but not with BMD at lumbar spine (r = -0.065, P = 0.682) or hip (r = -0.029, P = 0.857). When adjusting by age, similar results were found for PTH (r = -0.441, P = 0.005), BMD at lumbar spine (r = -0.026, P = 0.874) and hip (r = -0.096, P = 0.561). After multivariate linear regression, forcing bioavailable 25-hydroxyvitamin D into the model resulted in a weak significant association with BMD at the lumbar spine (ß = - 0.247, P = 0.025). CONCLUSIONS: Serum bioavailable 25-hydroxyvitamin D concentrations are not associated with bone mass loss after bariatric surgery in women. The negative association with serum PTH levels suggests that vitamin D supplementation partly improves secondary hyperparathyroidism, yet other mechanisms may contribute to low bone mass after bariatric surgery.

A nontargeted study of muscle proteome in severely obese women with androgen excess compared with severely obese men and nonhyperandrogenic women.

OBJECTIVE: Androgen excess in women is frequently associated with muscle insulin resistance, especially in obese women with polycystic ovary syndrome. However, whether this is a primary event or the result of indirect mechanisms is currently debated. DESIGN: This is an observational study. METHODS: We obtained skeletal muscle biopsies during bariatric surgery from severely obese men (n=6) and women with (n=5) or without (n=5) androgen excess. We used two-dimensional differential gel electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight mass spectrometry to identify muscle proteins showing differences in abundance between the groups of obese subjects. RESULTS: Women with hyperandrogenism presented the lowest abundances of glycogen phosphorylase, pyruvate kinase, ß-enolase, glycerol-3-phosphate dehydrogenase, creatine kinase M-type, and desmin, whereas the abundances of these molecules were similar in control women and men. CONCLUSION: According to our nontargeted proteomic approach, women with hyperandrogenism show a specific alteration of the skeletal muscle proteome that could contribute to their insulin resistance. Because men do not show similar results, this alteration does not appear to be the direct effect on muscle of androgen excess, but rather the consequence of indirect mechanisms that merit further studies.

Identification of reduced circulating haptoglobin concentration as a biomarker of the severity of pulmonary embolism: a nontargeted proteomic study.

Risk stratification of patients with pulmonary embolism (PE) may identify patients at high risk of early death who may benefit from more intensive surveillance or aggressive therapy. Nontargeted proteomics may identify biomarkers useful for the risk stratification of patients with acute symptomatic pulmonary embolism (PE). We studied 6 patients presenting with low-risk PE and 6 patients presenting with intermediate (n = 3) or high-risk (n = 3) PE. Two-dimensional difference gel electrophoresis was used to compare their plasma protein abundances. Candidate protein markers were identified by matrix assisted laser desorption ionization time-of-flight mass spectrometry. A panel of four biomarkers (haptoglobin, hemopexin, α2-macroglobulin, and Ig α1-chain C region) showed differences in plasma abundance among patients with acute symptomatic PE of different severity. Haptoglobin and hemopexin were decreased, whereas α2-macroglobulin and Ig α1-chain C region were increased, in patients with high or intermediate-risk PE compared with low-risk PE patient. In a separate clinical population consisting of 104 adults with acute PE, serum haptoglobin concentrations had an 85% chance of correctly identifying patients with high-risk PE according to receiving operating characteristics curve analysis. Moreover, serum haptoglobin concentrations ≤1 g/l showed an 80% sensitivity and a 96% specificity for the diagnosis of high-risk PE. Nontargeted proteomics identified protein biomarkers for the severity of PE that are involved in iron metabolism pathways and acute-phase response. Among them, reduced serum haptoglobin concentrations show a high accuracy for the biochemical detection of high-risk PE.

Sexual dimorphism in adipose tissue function as evidenced by circulating adipokine concentrations in the fasting state and after an oral glucose challenge.

STUDY QUESTION: Do the circulating levels of a panel of adipokines involved in glucose metabolism exhibit sexual dimorphism in the fasting state and after an oral glucose load? SUMMARY ANSWER: Our results indicate sexual dimorphism in the circulating concentrations of adipokines involved in intermediate metabolism in the fasting state and during an oral glucose load. This finding suggests an influence of sex steroids on adipose tissue function. WHAT IS KNOWN ALREADY: Sexual dimorphism in adipose tissue distribution fully develops after puberty and modulates the risk for cardiometabolic disorders. However, the possibility that adipose tissue function exhibits sexual dimorphism as well as its distribution is unproved. STUDY DESIGN, SIZE, DURATION: Cross-sectional case-control study including 32 subjects. PARTICIPANTS/MATERIALS, SETTING, METHODS: Sixteen subjects with weight excess (8 men and 8 women, including 4 overweight and 4 obese subjects in each group) and 16 normal weight healthy volunteers (8 men and 8 women) presenting with similar age were submitted to a 75-g oral glucose tolerance test (oGTT). We measured circulating concentrations of insulin, glucose, chemerin, lipocalin-2, omentin-1, leptin and adiponectin and calculated their areas under the oGTT curve (AUC). MAIN RESULTS AND THE ROLE OF CHANCE: Leptin and adiponectin concentrations were higher throughout the oGTT in women compared with men. Lipocalin-2 concentrations decreased during the oGTT in the whole group of study subjects. However, these levels remained higher in men with weight excess compared with normal weight men, whereas in women with weight excess lipocalin-2 levels at the end of the oGTT were lower compared with normal weight women. Sex was among the main determinants of the AUC of omentin-1 and leptin in linear regression models, and lower estradiol and testosterone concentrations were related to higher AUC of chemerin and omentin-1, respectively. Subjects with weight excess had higher AUC of chemerin and leptin and lower AUC of omentin-1 and adiponectin levels, independently of sex. LIMITATIONS, REASONS FOR CAUTION: We included a relatively small sample size and, because this was a cross-sectional study, we cannot infer causality to the associations between the changes in circulating adipokine concentrations and the variables studied here. WIDER IMPLICATIONS OF THE FINDINGS: Sexual dimorphism in adipose tissue function should be considered when studying adiposity and obesity, and also when designing strategies for their diagnosis and management.

Proteomic and metabolomic approaches to the study of polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is considered a complex multifactorial disorder resulting from the interaction of genetic, environmental, and lifestyle influences. Nontargeted proteomics and metabolomics have been used in the past years with the aim of identifying molecules potentially involved in the pathophysiology of this frequent disorder. The biomolecules identified so far participate in many metabolic pathways, including energy metabolism (glucose and lipid metabolism), protein metabolic processes and protein folding, cytoskeleton structure, immune response, inflammation and iron metabolism, fibrinolysis and thrombosis, oxidative stress and intracellular calcium metabolism. These molecules provide key information about molecular functions altered in PCOS and raise questions concerning their precise role in the pathogenesis of this syndrome. The biomolecules identified by nontargeted proteomic and metabolomic approaches should be considered as candidates in future studies aiming to define specific molecular phenotypes of PCOS.

A nontargeted proteomic study of the influence of androgen excess on human visceral and subcutaneous adipose tissue proteomes.

CONTEXT: Sex hormones, particularly androgens, may influence not only adipose tissue distribution but also its functions. OBJECTIVE: We aimed to evaluate if sexual dimorphism in body composition is accompanied by differences in the protein abundance of adipose tissue by applying a nontargeted proteomic approach. DESIGN: This was a case-control study. SETTINGS: The setting was an academic hospital. PATIENTS: Twenty-one morbidly obese patients, including 7 men, 7 women showing no evidence of androgen excess, and 7 hyperandrogenic women with polycystic ovary syndrome. INTERVENTIONS: We obtained subcutaneous (SAT) and visceral (VAT) adipose tissue samples during bariatric surgery. MAIN OUTCOME MEASURES: Protein abundance in VAT and SAT was analyzed by 2-dimensional differential gel electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight coupled to mass spectrometry. Results were validated by RT-PCR. RESULTS: The abundance of 2 spots of peroxiredoxin 6, creatine kinase B-type, 2 spots of selenium-binding protein 1, ruvB-like 2, 4-trimethylaminobutyraldehyde dehydrogenase, and albumin were higher in VAT compared with SAT in women with polycystic ovary syndrome. Men showed a similar pattern, whereas no difference between adipose tissue depots was observed in control women. Other proteins showed differences between VAT and SAT, confirming previous studies, or between the groups of subjects, without interaction between both effects. Several findings were confirmed by RT-PCR. CONCLUSIONS: Sexual dimorphism influences the abundance of several proteins in VAT and SAT. The patterns of abundance in adipose tissue depots of several proteins involved in metabolic processes were similar in women with androgen excess and in men, suggesting that androgens influence adipose tissue function.

Evidence for masculinization of adipokine gene expression in visceral and subcutaneous adipose tissue of obese women with polycystic ovary syndrome (PCOS).

CONTEXT: Sex hormones, particularly androgens, may influence not only adipose tissue distribution but also its functions. OBJECTIVE: We explored the possibility of sexual dimorphism in adipose tissue and skeletal muscle function. DESIGN: This was a case-control study. SETTING: The setting was an academic hospital. PARTICIPANTS: Participants were severely obese men (n = 7), control women (n = 7), and hyperandrogenic women presenting with polycystic ovary syndrome (PCOS) (n = 7) submitting to bariatric surgery and an independent series of 40 patients with PCOS and 40 control women matched for age and body mass index. INTERVENTIONS: Samples of subcutaneous (SAT) and visceral adipose tissue (VAT) and skeletal muscle were obtained during bariatric surgery in severely obese subjects. MAIN OUTCOME MEASURES: Gene expression of chemerin, lipocalin-2, and omentin-1 in tissue samples was measured. We analyzed the effects of PCOS and obesity on serum concentrations of these adipokines in the larger series of women with PCOS and in control women. RESULTS: Expression of chemerin and lipocalin-2 was higher in VAT than in SAT in men and women with PCOS; the opposite was observed in control women. Omentin-1 expression was higher in VAT than in SAT in the three groups. No differences were observed in the skeletal muscle expression of these adipokines. Obesity increased serum chemerin and lipocalin-2 levels and tended to decrease omentin-1, irrespective of PCOS. CONCLUSIONS: The present results suggest that there is sexual dimorphism in some adipose tissue functions and that this dimorphism may be related to differences in androgen concentrations because women with PCOS show a masculinized pattern of expression of some adipokines.

A nontargeted proteomic approach to the study of visceral and subcutaneous adipose tissue in human obesity.

Subcutaneous (SAT) and visceral adipose tissue (VAT) differ in biochemical and metabolic properties, especially when obesity is present. We submitted paired SAT and VAT samples from six morbidly obese patients and six non-obese persons to two-dimensional differential gel electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight mass spectrometry. Compared with non-obese subjects, obese patients presented with increased carboxylesterase-1, zinc finger protein 324A, annexin A5, ubiquitin carboxyl-terminal hydrolase, α-crystallin B chain, osteoglycin, retinal dehydrogenase-1 and 14-3-3 protein γ, and decreased transferrin, complement C3, fibrinogen γ chain, albumin, α1-antitrypsin and peroxiredoxin-6, irrespective of the adipose tissue depot studied. SAT and VAT differed in protein species of fibrinogen and osteoglycin, whereas adipose tissue depot and obesity interacted on the protein abundance of actin, α-actinin 1, one protein species of carboxylesterase-1, retinal dehydrogenase-1 and 14-3-3 protein γ. Our nontargeted proteomic approach identified novel protein species that may be involved in the development of obesity in humans.

Environmental monitoring of Domingo Rubio stream (Huelva Estuary, SW Spain) by combining conventional biomarkers and proteomic analysis in Carcinus maenas.

Element load, conventional biomarkers and altered protein expression profiles were studied in Carcinus maenas crabs, to assess contamination of "Domingo Rubio" stream, an aquatic ecosystem that receives pyritic metals, industrial contaminants, and pesticides. Lower antioxidative activities - glucose-6-phosphate and 6-phosphogluconate dehydrogenases, catalase - were found in parallel to higher levels of damaged biomolecules - malondialdehyde, oxidized glutathione -, due to oxidative lesions promoted by contaminants, as the increased levels of essential - Zn, Cu, Co - and nonessential - Cr, Ni, Cd - elements. Utility of Proteomics to assess environmental quality was confirmed, especially after considering the six proteins identified by de novo sequencing through capLC-muESI-ITMS/MS and homology search on databases. They include tripartite motif-containing protein 11 and ATF7 transcription factor (upregulated), plus CBR-NHR-218 nuclear hormone receptor, two components of the ABC transporters and aldehyde dehydrogenase (downregulated). These proteins could be used as novel potential biomarkers of the deleterious effects of pollutants present in the area.

Proteomics in free-living Mus spretus to monitor terrestrial ecosystems.

We evaluated the suitability of high-throughput proteomic methods to monitor terrestrial ecosystems. Free-living Mus spretus from three sites along the "Domingo Rubio" (DR) stream were compared with mice from Doñana Biological Reserve ("Santa Olalla" lagoon (SOL) negative control), using specimens from an industrial settlement (phosphogypsum stacks (PS)) and rice fields ("Matochal" rice fields (ARZ)) as positive controls. Our 2-DE analysis showed 36 spots with significantly altered expression. Sixteen were identified by MALDI-TOF-PMF and peptide matching with Mus musculus databases. Identified proteins play different roles: cytoskeletal dynamics, proteolysis, biotransformation, oxidative-stress adaptation, and metabolism. Animals from different polluted environments showed contrasting differences in their proteomes, with specific increases and decreases in selected groups of proteins that seem to be co-ordinately regulated. Proteomic data were consistent with metal biomonitoring and conventional biomarker responses, indicating that DR (and PS/ARZ) animals sustained a heavier pollutant burden than SOL specimens and suffered a chronic oxidative stress. Whereas some protein expression differences may protect mice from pollutant toxicity, others should make them more susceptible. Transcript expression signatures agree with the documented lack of correlation between mRNA and protein levels. Nonetheless, a positive significant correlation was found between the gpx1 mRNA molecules and the intensity of one of the two identified GPX1 isospots.