A cysteine-rich adipose tissue-specific secretory factor inhibits adipocyte differentiation

Resistin affects lipid metabolism during adipocyte maturation of 3T3-L1 cells

Resistin, an adipose-tissue-specific secretory factor, aggravates metabolic syndrome through impairment of glucose metabolism. Previously, we demonstrated that resistin expression was induced in both 3T3-L1 cells and primary pre-adipocytes derived from Zucker obese rats during the process of differentiation and maturation (Ikeda Y, Hama S, Kajimoto K, Okuno T, Tsuchiya H & Kogure K (2011) Biol Pharm Bull 34, 865-870). However, the biological function of resistin in adipocytes is poorly understood. In the present study, we examined the effects of resistin knockdown on the biological features of 3T3-L1 cells. We found that lipid content was significantly decreased in 3T3-L1 cells transfected with anti-resistin small interfering RNA (siRNA) after adipocyte differentiation. While expression of peroxisome proliferator activated receptor γ and CCAAT/enhancer-binding protein α was not affected, protein expression and transcriptional activity levels of carbohydrate response element binding protein (ChREBP), which upregulates transcription of lipogenic genes, decreased after anti-resistin siRNA treatment. Moreover, gene expression of fatty acid synthase and acetyl-CoA carboxylase 2, which are known to be regulated by ChREBP, were also suppressed by resistin knockdown. In contrast, activity of the fatty acid β-oxidation-regulating protein carnitine palmitoyltransferase 1 increased. These results suggest that resistin knockdown induces suppression of lipid production and activation of fatty acid β-oxidation. Consequently, resistin may affect lipid metabolism during adipocyte maturation.

Rapid cloning and comparative sequence analysis of full-length cDNA of Rhesus monkey (Macaca mulatta) resistin

Resistin protein is thought to link insulin resistance in murine models of obesity and type-2 diabetes, but the role of resistin in human studies of inflammatory metabolic disorders have generated conflicting data. Here, we describe the structure of the resistin gene using adipose tissue from non-human primates (NHPs), which have been used extensively to model a host of human diseases. Full-length cDNA from rhesus macaque resistin obtained by rapid amplification of cDNA ends (RACE) is comprised of 526 nucleotides covering an open-reading frame (ORF) that encodes a 108-amino-acid protein that is 92% homologous with the human counterpart but only 60% homologous with the murine counterpart. Using a modified polymerase chain reaction technique, we identified single nucleotide polymorphisms and a 78-bp deletion within resistin cDNA of nine rhesus macaques. Comparisons of the full-length cDNA sequence and an amplified 569-bp genomic DNA sequence revealed an error in published predictions arising from genomic studies about the gene's exon 3 region. Our data show, for the first time, the full-length macaque resistin cDNA sequence (GenBank: JF740676.1). These findings will illuminate future studies into the role of resistin in NHP models of inflammatory metabolic diseases.

Resistin and all-cause and cardiovascular mortality: effect modification by adiponectin in end-stage kidney disease patients

BACKGROUND

Resistin is a major adipose tissue cytokine implicated in insulin resistance, inflammation and vascular damage. This cytokine is raised in patients with end-stage kidney disease (ESKD) but the relationship between resistin and major clinical outcomes has not been investigated in this population.

METHODS

We studied the mutual relationship between resistin and the two major adipokines (adiponectin and leptin) and the interaction between resistin and adiponectin (ADPN) and all-cause and cardiovascular (CV) mortality in a cohort of 231 haemodialysis patients followed up for 57 ± 44 months.

RESULTS

Plasma resistin was substantially raised in ESKD patients when compared with healthy subjects (P < 0.001). On univariate analysis, resistin was related inversely to ADPN (r = -0.14, P = 0.04) and directly to C-reactive protein (r = 0.15, P = 0.03), but was largely independent of leptin (r = 0.08, P = 0.24) and the HOMA-IR index (r = -0.04, P = 0.51). During the follow-up, 165 patients died (96 for CV causes). On both univariate (all-cause mortality: P = 0.004; CV mortality P < 0.001) and multivariate (all-cause mortality: P = 0.01; CV mortality P < 0.001) Cox regression analyses, the effect of resistin on study outcomes was closely dependent on ADPN levels. There was a consistent excess risk for all-cause (P = 0.002) and CV mortality (P = 0.003) by plasma resistin (20 ng/mL) in patients in the first ADPN tertile, but no risk excess for these outcomes was apparent in patients in the third tertile.

CONCLUSION

This study indicates that resistin predicts death and fatal CV events depending on plasma ADPN levels. These findings underscore the importance of the interaction among adipokines for the prediction of adverse clinical outcomes in ESKD.

Resistin in mid-trimester amniotic fluid in trisomy 21

OBJECTIVE

The aim of this study was to examine whether resistin is present in second trimester amniotic fluid from trisomy 21 (also known as Down's syndrome) pregnancies and whether its concentration differs compared with euploid pregnancies.

METHODS

The study cohort consisted of 58 women in the mid-trimester of pregnancy who underwent amniocentesis for prenatal diagnosis, 31 of whom carried a single fetus with diagnosed trisomy 21 (study group) and the rest with normal karyotype (control group, n = 27). Groups were matched for maternal and gestational age. Levels of resistin in amniotic fluid were measured by a commercially available enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

Resistin was detected in all amniotic fluid samples. Its median concentration in the second trimester amniotic fluid of trisomy 21 pregnancies (2.1 ng/ml) was statistically significantly lower (p value <0.001) in comparison with that in euploid pregnancies (3.3 ng/ml).

CONCLUSIONS

Resistin is a physiologic constituent of second trimester amniotic fluid. Lower levels of amniotic fluid resistin in pregnancies with trisomy 21 may reflect altered metabolic pathways in utero that could possibly be related with phenotypic features of the syndrome.

Adipo-myokines: two sides of the same coin--mediators of inflammation and mediators of exercise

This review summarizes the current literature regarding the most discussed contraction-regulated moykines like IL-6, IL-15, irisin, BDNF, ANGPTL4, FGF21, myonectin and MCP-1. It is suggested that the term myokine is restricted to proteins secreted from skeletal muscle cells, excluding proteins that are secreted by other cell types in skeletal muscle tissue and excluding proteins which are only described on the mRNA level. Interestingly, many of the contraction-regulated myokines described in the literature are additionally known to be secreted by adipocytes. We termed these proteins adipo-myokines. Within this review, we try to elaborate on the question why pro-inflammatory adipokines on the one hand are upregulated in the obese state, and have beneficial effects after exercise on the other hand. Both, adipokines and myokines do have autocrine effects within their corresponding tissues. In addition, they are involved in an endocrine crosstalk with other tissues. Depending on the extent and the kinetics of adipo-myokines in serum, these molecules seem to have a beneficial or an adverse effect on the target tissue.

Identification of novel tissue-specific genes by analysis of microarray databases: a human and mouse model

Understanding the tissue-specific pattern of gene expression is critical in elucidating the molecular mechanisms of tissue development, gene function, and transcriptional regulations of biological processes. Although tissue-specific gene expression information is available in several databases, follow-up strategies to integrate and use these data are limited. The objective of the current study was to identify and evaluate novel tissue-specific genes in human and mouse tissues by performing comparative microarray database analysis and semi-quantitative PCR analysis. We developed a powerful approach to predict tissue-specific genes by analyzing existing microarray data from the NCBI′s Gene Expression Omnibus (GEO) public repository. We investigated and confirmed tissue-specific gene expression in the human and mouse kidney, liver, lung, heart, muscle, and adipose tissue. Applying our novel comparative microarray approach, we confirmed 10 kidney, 11 liver, 11 lung, 11 heart, 8 muscle, and 8 adipose specific genes. The accuracy of this approach was further verified by employing semi-quantitative PCR reaction and by searching for gene function information in existing publications. Three novel tissue-specific genes were discovered by this approach including AMDHD1 (amidohydrolase domain containing 1) in the liver, PRUNE2 (prune homolog 2) in the heart, and ACVR1C (activin A receptor, type IC) in adipose tissue. We further confirmed the tissue-specific expression of these 3 novel genes by real-time PCR. Among them, ACVR1C is adipose tissue-specific and adipocyte-specific in adipose tissue, and can be used as an adipocyte developmental marker. From GEO profiles, we predicted the processes in which AMDHD1 and PRUNE2 may participate. Our approach provides a novel way to identify new sets of tissue-specific genes and to predict functions in which they may be involved.

Peripheral signalling involved in energy homeostasis control

The alarming prevalence of obesity has led to a better understanding of the molecular mechanisms controlling energy homeostasis. Regulation of energy intake and expenditure is more complex than previously thought, being influenced by signals from many peripheral tissues. In this sense, a wide variety of peripheral signals derived from different organs contributes to the regulation of body weight and energy expenditure. Besides the well-known role of insulin and adipokines, such as leptin and adiponectin, in the regulation of energy homeostasis, signals from other tissues not previously thought to play a role in body weight regulation have emerged in recent years. The role of fibroblast growth factor 21 (FGF21), insulin-like growth factor 1 (IGF-I), and sex hormone-binding globulin (SHBG) produced by the liver in the regulation of body weight and insulin sensitivity has been recently described. Moreover, molecules expressed by skeletal muscle such as myostatin have also been involved in adipose tissue regulation. Better known is the involvement of ghrelin, cholecystokinin, glucagon-like peptide 1 (GLP-1) and PYY(3-36), produced by the gut, in energy homeostasis. Even the kidney, through the production of renin, appears to regulate body weight, with mice lacking this hormone exhibiting resistance to diet-induced obesity. In addition, the skeleton has recently emerged as an endocrine organ, with effects on body weight control and glucose homeostasis through the actions of bone-derived factors such as osteocalcin and osteopontin. The comprehension of these signals will help in a better understanding of the aetiopathology of obesity, contributing to the potential development of new therapeutic targets aimed at tackling excess body fat accumulation.

Inherited variation in miR-290 expression suppresses breast cancer progression by targeting the metastasis susceptibility gene Arid4b

The metastatic cascade is a complex and extremely inefficient process with many potential barriers. Understanding this process is of critical importance because the majority of cancer mortality is associated with metastatic disease. Recently, it has become increasingly clear that microRNAs (miRNA) play important roles in tumorigenesis and metastasis, yet few studies have examined how germline variations may dysregulate miRNAs, in turn affecting metastatic potential. To explore this possibility, the highly metastatic MMTV-PyMT mice were crossed with 25 AKXD (AKR/J × DBA/2J) recombinant inbred strains to produce F1 progeny with varying metastatic indices. When mammary tumors from the F1 progeny were analyzed by miRNA microarray, miR-290 (containing miR-290-3p and miR-290-5p) was identified as a top candidate progression-associated miRNA. The microarray results were validated in vivo when miR-290 upregulation in two independent breast cancer cell lines suppressed both primary tumor and metastatic growth. Computational analysis identified breast cancer progression gene Arid4b as a top target of miR-290-3p, which was confirmed by luciferase reporter assay. Surprisingly, pathway analysis identified estrogen receptor (ER) signaling as the top canonical pathway affected by miR-290 upregulation. Further analysis showed that ER levels were elevated in miR-290-expressing tumors and positively correlated with apoptosis. Taken together, our results suggest miR-290 targets Arid4b while simultaneously enhancing ER signaling and increasing apoptosis, thereby suppressing breast cancer progression. This, to the best of our knowledge, is the first example of inherited differences in miRNA expression playing a role in breast cancer progression.

Resistin reduces mitochondria and induces hepatic steatosis in mice by the protein kinase C/protein kinase G/p65/PPAR gamma coactivator 1 alpha pathway

Obesity is associated with many severe chronic diseases and deciphering its development and molecular mechanisms is necessary for promoting treatment. Previous studies have revealed that mitochondrial content is down-regulated in obesity, diabetes, and nonalcoholic fatty liver disease (NAFLD) and proposed that NAFLD and diabetes are mitochondrial diseases. However, the exact mechanisms underlying these processes remain unclear. In this study, we discovered that resistin down-regulated the content and activities of mitochondria, enhanced hepatic steatosis, and induced insulin resistance (IR) in mice. The time course indicated that the change in mitochondrial content was before the change in fat accumulation and development of insulin resistance. When the mitochondrial content was maintained, resistin did not stimulate hepatic fat accumulation. The present mutation study found that the residue Thr464 of the p65 subunit of nuclear factor kappa B was essential for regulating mitochondria. A proximity ligation assay revealed that resistin inactivated peroxisome proliferator activated receptor gamma coactivator 1 alpha (PGC-1α) and diminished the mitochondrial content by promoting the interaction of p65 and PGC-1α. Signaling-transduction analysis demonstrated that resistin down-regulated mitochondria by a novel protein kinase C/protein kinase G/p65/PGC-1α-signaling pathway.

CONCLUSION

Resistin induces hepatic steatosis through diminishing mitochondrial content. This reveals a novel pathway for mitochondrial regulation, and suggests that the maintenance of normal mitochondrial content could be a new strategy for treatment of obesity-associated diseases.

Adipokines in reproductive function: a link between obesity and polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy associated with infertility and metabolic disorder in women of reproductive age. Dysfunction of adipose tissue has been implicated in the pathophysiology of PCOS. Increasing evidence shows that the dysregulated expression of adipokines, the secreted products of adipose tissue, plays an important role in the pathology of PCOS. Here, we review the role of several identified adipokines that may act as a link between obesity and PCOS. PCOS also reciprocally influences the profile of adipokines. Insight into the underlying mechanisms will help better understand the pathology of PCOS and identify new therapeutic targets of this syndrome.

Human resistin inhibits myogenic differentiation and induces insulin resistance in myocytes

This study is aimed to investigate the effect of human resistin on myocyte differentiation and insulin resistance. The human resistin eukaryotic expression vector was stable transfected into C2C12 myocyte cells and was transiently transfected into COS7 cells. The effects of human resistin on cell proliferation, cell cycle, and myogenic differentiation of C2C12 cells were examined. Glucose uptake assays was performed on C2C12 myotubes by using [³H] 2-deoxy-D-glucose. The mRNA levels of insulin receptor (IR) and glucose transporter 4 (GLUT4) were evaluated by semiquantitative RT-PCR. Results showed by the C2C12 cells transfected with human resistin gene compared with that without transfecting gene are as follows: (1) cell proliferation was significantly promoted, (2) after inducing differentiation, the myotube's diameters and expression of desmin and myoglobin decreased, and (3) glucose uptake ratio was lowered and expression of IR and GLUT4 decreased. However, there was no significant difference in the glucose uptake ratio between C2C12 myotubes treated with a human resistin conditioned medium of COS7 cells and treated with control medium. These results suggest that maybe human resistin has not a direct role on insulin sensitivity of myocytes. However, maybe it impaired the insulin sensitivity of myocytes through suppressing myogenesis and stimulating proliferation of myoblasts.

Mesenchymal stem cells: a revolution in therapeutic strategies of age-related diseases

The great evolutionary biologist Theodosius Dobzhansky once said: "Nothing in biology makes sense except in the light of evolution". Aging is a complex biological phenomenon and the factors governing the process of aging and age-related diseases are only beginning to be understood, oxidative stress, telomere shortening in DNA components and genetic changes were shown to be the mainly regulating mechanisms during the recent decades. Although a considerable amount of both animal and clinical data that demonstrate the extensive and safe use of mesenchymal stromal cells (MSCs) is available, the precise summarization and identification of MSCs in age-related diseases remains a challenge. Along this line, this review discussed several typical age-related diseases for which MSCs have been proved to confer protection and put forward a hypothesis for the association among MSCs and age-related diseases from an evolutionary perspective. Above all, we hope further and more research efforts could be aroused to elucidate the role and mechanisms that MSCs involved in the age-related diseases.

High insulin and leptin increase resistin and inflammatory cytokine production from human mononuclear cells

Resistin and the proinflammatory cytokines, such as TNF-α, IL-6, and IL-1β, produced by adipocytes, and macrophages, are considered to be important modulators of chronic inflammation contributing to the development of obesity and atherosclerosis. Human monocyte-enriched mononuclear cells, from ten healthy individuals, were exposed to high concentrations of insulin, leptin, and glucose (alone or in combination) for 24 hours in vitro. Resistin, TNF-α, IL-6, and IL-1β production was examined and compared to that in untreated cells. High insulin and leptin concentrations significantly upregulated resistin and the cytokines. The subsequent addition of high glucose significantly upregulated resistin and TNF-α mRNA and protein secretion, while it did not have any effect on IL-6 or IL-1β production. By comparison, exposure to dexamethasone reduced TNF-α, IL-6, and IL-1β production, while at this time point it increased resistin protein secretion. These data suggest that the expression of resistin, TNF-α, IL-6, and IL-1β from human mononuclear cells, might be enhanced by the hyperinsulinemia and hyperleptinemia and possibly by the hyperglycemia in metabolic diseases as obesity, type 2 diabetes, and atherosclerosis. Therefore, the above increased production may contribute to detrimental effects of their increased adipocyte-derived circulating levels on systemic inflammation, insulin sensitivity, and endothelial function of these patients.

Resistin polymorphisms show associations with obesity, but not with bone parameters in men: results from the Odense Androgen Study

Resistin is an obesity-related adipokine which has also been implicated in bone metabolism. Therefore, we designed a study to investigate the possible role of resistin gene variation in both obesity and bone mineral density. We included 1,155 individuals from the Odense Androgen Study (663 young subjects and 492 older subjects), a population-based, prospective, observational study on the inter-relationship between endocrine status, body composition, muscle function, and bone metabolism in men, in an association study with resistin (RETN) polymorphisms. Three RETN variants (rs1862513, rs3745367 and rs3745369) were genotyped with TaqMan Pre-Designed Genotyping assays. Linear regression was performed to investigate the possible association of these variants with several obesity- and bone-related parameters. After genotyping 1,155 Danish men, 663 young subjects and 492 older subjects, we found that rs3745367 was associated with several obesity-related measures in both the young and elderly cohort. Rs3745369 was only associated with obesity-phenotypes in the elderly cohort. When studying the combined cohorts, we could confirm the associations of rs3745367 with several obesity-related parameters. We were unable to identify any association between RETN polymorphisms and bone-related measurements. Together, these results illustrate resistin's role in the development of obesity. Rs3745367 gives the most consistent results in the current study and these should be confirmed in other populations. Research into its possible functional effect might also be required. A role for RETN variants in determining bone mineral density seems unlikely from our results.

Choosing the right antibody for resistin-like molecule (RELM/FIZZ) family members

The family of resistin-like molecules (RELM), also known as found in inflammatory zone (FIZZ), consists of four members in mouse (RELMα/FIZZ1/HIMF, RELMβ/FIZZ2, Resistin/FIZZ3, and RELMγ/FIZZ4) and two members in human (resistin and RELMβ). The importance of these proteins in many aspects of physiology and pathophysiology, especially inflammatory processes, is rapidly evolving in the literature, and many investigators are beginning to work in this field. Most published studies focus on only one isoform, do not evaluate other isoforms that might be present, and have not tested for the specificity of the antibody used. Because RELM isoforms have high sequence and structural similarity and both distinct and overlapping functions, it is important to use a specific antibody to distinguish each isoform in the study. We constructed and established HEK 293 cell lines that constitutively express each isoform. Using these cell lines, we determined the specificity of antibodies (both commercially available and laboratory-made) to each isoform by Western blot and immunofluorescence. Some of the antibodies showed specificity in Western blotting but were not applicable in immunofluorescence. Others showed cross reactivity in Western blot assays. Our results indicate that RELM antibody specificity should be taken into account when using them in research and interpreting data obtained with them.

Resistin-like molecule α stimulates proliferation of mesenchymal stem cells while maintaining their multipotency

Resistin-like molecule α (RELMα) is highly upregulated in the lungs of mice subjected to hypoxia. It is secreted from pulmonary epithelium and causes potent mitogenic, angiogenic, and vasoconstrictive effects in the lung vasculature. By using bone marrow transplantation in mice, we previously showed that RELMα is able to increase the number of bone marrow-derived cells in lung tissue, especially in the remodeling pulmonary vasculature. The current study investigated the effect of RELMα on progenitor stem cell content in mouse lung. Hypoxia, while stimulating RELMα expression, caused an increase in the number of Sca1(+)/CD45(-) progenitor cells in lungs of wild-type mice, but not in lungs of RELMα knockout mice. An in vitro study with cultured mesenchymal stem cells (MSCs) showed that RELMα induced a robust proliferative response that was dependent on Phosphatidylinositol 3-kinase/Akt and Erk activation. RELMα treatment of MSCs caused upregulation of a large number of genes involved in cell cycle, mitosis, organelle, and cytoskeleton biogenesis, and DNA metabolism. MSCs cultured in RELMα-supplemented media were able to maintain their differentiation potential into adipogenic, osteogenic, or mesenchymal phenotypes, although adipogenic differentiation was partially inhibited. These results demonstrate that RELMα may be involved in stem cell proliferation in the lung, without affecting differentiation potential.

Resistin and leptin in breast milk and infants in early life

BACKGROUND

The role of adipokines in early life is considered an emerging topic issue in nutritional researches.

AIMS

To evaluate serum resistin and leptin concentrations and their relations in infants and in breast milk.

STUDY DESIGN

We enrolled 41 term, AGA, healthy infants, of which 23 exclusively breast-fed (BF) and 18 formula-fed (FF), aged less than 6 months. Breast milk (BM) samples were collected from 23 breastfeeding mothers of the infants enrolled. Resistin concentration in serum and BM was determined by ELISA test (Human-Resistin-ELISA, Mediagnost, Reutlingen, Germany). Leptin concentration was determined by Radioimmunoassay method (LEP-R40, Mediagnost, Reutlingen, Germany). Infants weight, length and body mass index were measured. We used Mann-Whitney test. Spearman correlation was applied. Statistical significance was set at p<0.05. Data are reported as median and interquartile range (IR).

RESULTS

Infants serum resistin concentration was 9.30 (5.02) ng/ml. Breast milk resistin concentration (n=23) was 0.18 (0.44) ng/ml. Leptin concentration was 3.04 (3.68) ng/ml in infants serum and in BM was 2.34 (5.73) ng/ml. Serum resistin concentrations in BF infants correlated positively with BM resistin (r=0.636, p=0.035). We have shown a positive correlation between resistin and leptin in total group of infants (r=0.44, p=0.05), confirmed in breastfed subjects (r=0.65, p=0.02). No correlations were found between serum hormones and anthropometric parameters of infants.

CONCLUSION

Our findings show interestingly a positive correlation between resistin concentrations in BF infants serum and in BM and between resistin and leptin in infants.

Differential effects of environmental chemicals and food contaminants on adipogenesis, biomarker release and PPARγ activation

Eleven environmental relevant chemicals were investigated for their ability to affect adipogenesis in vitro, biomarker release from adipocytes and PPARα and γ activation. We found that butylparaben stimulated adipogenesis in 3T3-L1 adipocytes and increased release of leptin, adiponectin and resistin from the cells. Butylparaben activated PPARγ as well, which may be a mediator of the adipogenic effect. Polychlorinated biphenyl (PCB)153 also stimulate adipogenesis and biomarker release, but did not affect PPARs. The data indicates that PPARγ activating chemicals often stimulate adipocyte differentiation although PPARγ activation is neither a requirement nor a guarantee for stimulation. Four out of the eleven chemicals (bisphenol A, mono-ethylhexyl phthalate, butylparaben, PCB 153) caused increased adipogenesis. The release of adipocyte-secreted hormones was sometimes but not always correlated with the effect on adipocyte differentiation. Eight chemicals were able to cause increased leptin release. These findings strengthen the hypothesis that chemicals can interfere with pathways related to obesity development.

Human resistin in cardiovascular disease

An adipokine, resistin, was discovered as a potential mediator of obesity related insulin resistance in rodents. However, the relevance of resistin in human obesity and insulin resistance has been challenged by the difference between human and rodent resistin and the controversies in human epidemiologic studies. Instead, recent human clinical studies and experiments support the idea that human resistin is an inflammatory mediator and a biomarker of cardiovascular diseases, especially in atherosclerosis and heart failure. Thus, we focused on the recent evidence of the role of human resistin in cardiovascular disease.

Association of resistin with metabolic syndrome in Indian subjects

BACKGROUND

The role of resistin in insulin sensitivity and metabolic syndrome has been controversial until now. Increased plasma/serum resistin levels are associated with metabolic syndrome and insulin resistance. The aim of this study was to investigate the relationship between serum resistin levels with markers of metabolic syndrome in males.

METHODS

A total of 386 male volunteers were enrolled in a case-control study. All of the enrolled volunteers were analyzed to confirm metabolic syndrome following the guidelines of National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) of 2001. Of the 386 volunteers, 192 were categorized as cases of metabolic syndrome, whereas 194 were registered as controls without metabolic syndrome. Volunteers enrolled in the study were analyzed for anthropometrical parameters, lipid profile status, insulin, insulin resistance, and resistin.

RESULTS

Higher levels of resistin were observed in cases when compared to controls (12.49 ± 4.73 ng/mL vs. 6.99 ± 1.98 ng/mL). Resistin was positively and significantly associated with serum triglyceride, cholesterol, and very-low-density lipoprotein, whereas it was negatively and significantly associated with serum high-density lipoprotein (HDL) levels. Multiple regression analysis of the data observed indicated that the triglyceride level was the major determinant for the development of metabolic syndrome in male samples.

CONCLUSION

This study demonstrates a positive correlation between resistin and factors of metabolic syndrome, except for HDL cholesterol (HDL-C), which was found to be negatively correlated in Indian male subjects. The study also found resistin to be a suitable peripheral blood marker.

LOX-1 and obesity

Obesity is one of the most common lifestyle-related diseases. Being closely associated with insulin resistance, hypertension and dyslipidemia, it is also a component of metabolic syndrome and is involved in the development of atherosclerosis and cardiovascular and renal ailments. Obesity is also accompanied with a state of chronic inflammation. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), a receptor for oxidized low density lipoprotein (ox-LDL), is expressed not only in endothelial cells, but also in macrophages, vascular smooth muscle cells, platelets and adipocytes. LOX-1 binds multiple ligands, has diverse physiological functions and plays a critical role in the signal transduction. It may well turn out to be a key, or very important, factor in the development of hypertension, diabetes mellitus and hyperlipidemia, the most important risk factors for atherosclerosis. In recent studies, LOX-1 upregulation appears to be a vital factor in obesity and its complications. This review summarizes current knowledge of obesity and the relationship between LOX-1 and obesity.

Maternal serum resistin at 11 to 13 weeks' gestation in normal and pathological pregnancies

The objective was to examine maternal serum levels of resistin at 11 to 13 weeks' gestation in normal and pathological pregnancies. Serum resistin, pregnancy-associated plasma protein A (PAPP-A), and uterine artery pulsatility index (PI) at 11 to 13 weeks were measured in 480 singleton pregnancies, including 240 with normal outcome, 60 that subsequently developed preeclampsia (PE), 60 that developed gestational diabetes mellitus (GDM), 60 that delivered large for gestational age (LGA) neonates, and 60 that delivered small for gestational age (SGA) neonates. Each value in both the normal and pathological outcome groups was expressed as a multiple of the expected normal median (MoM), and the median MoM values in the outcome groups were compared. In the PE group, compared with the controls, there were an increase in median resistin (1.22 MoM, P = .003) and uterine artery PI (1.25 MoM, P < .0001) and a decrease in serum PAPP-A (0.72, P < .0001). There was no significant association between serum resistin with either uterine artery PI (P = .415) or serum PAPP-A (P = .290). In the SGA, LGA, and GDM groups, serum resistin MoM was not significantly different from that of the controls (P = .415, P = .702, and P = .549, respectively). In pregnancies that develop PE, maternal serum resistin concentration at 11 to 13 weeks is increased in a manner not related to altered placental perfusion or function. In pregnancies complicated by the development of GDM or delivery of SGA or LGA neonates, serum resistin is not significantly altered.

Deficiency of lymphotoxin-α does not exacerbate high-fat diet-induced obesity but does enhance inflammation in mice

Lymphotoxin-α (LTα) is secreted by lymphocytes and acts through tumor necrosis factor-α receptors and the LTβ receptor. Our goals were to determine whether LT has a role in obesity and investigate whether LT contributes to the link between obesity and adipose tissue lymphocyte accumulation. LT deficient (LT(-/-)) and wild-type (WT) mice were fed standard pelleted rodent chow or a high-fat/high-sucrose diet (HFHS) for 13 wk. Body weight, body composition, and food intake were measured. Glucose tolerance was assessed. Systemic and adipose tissue inflammatory statuses were evaluated by quantifying plasma adipokine levels and tissue macrophage and T cell-specific gene expression in abdominal fat. LT(-/-) mice were smaller (20%) and leaner (25%) than WT controls after 13 wk of HFHS diet feeding. LT(-/-) mice showed improved glucose tolerance, suggesting that, in WT mice, LT may impair glucose metabolism. Surprisingly, adipose tissue from rodent chow- and HFHS-fed LT(-/-) mice exhibited increased T lymphocyte and macrophage infiltration compared with WT mice. Despite the fact that LT(-/-) mice exhibited an enhanced inflammatory status at the systemic and tissue level even when fed rodent chow, they were protected from enhanced diet-induced obesity and insulin resistance. Thus, LT contributes to body weight and adiposity and is required to modulate the accumulation of immune cells in adipose tissue.

Inflammation and oxidative stress in obesity-related glomerulopathy

Obesity-related glomerulopathy is an increasing cause of end-stage renal disease. Obesity has been considered a state of chronic low-grade systemic inflammation and chronic oxidative stress. Augmented inflammation in adipose and kidney tissues promotes the progression of kidney damage in obesity. Adipose tissue, which is accumulated in obesity, is a key endocrine organ that produces multiple biologically active molecules, including leptin, adiponectin, resistin, that affect inflammation, and subsequent deregulation of cell function in renal glomeruli that leads to pathological changes. Oxidative stress is also associated with obesity-related renal diseases and may trigger the initiation or progression of renal damage in obesity. In this paper, we focus on inflammation and oxidative stress in the progression of obesity-related glomerulopathy and possible interventions to prevent kidney injury in obesity.

Circulating levels of resistin, IL-6 and lipid profile in elderly patients with ischemic heart disease with and without diabetes

Background: The cytokines that act as inflammatory hormones show a role in coronary atherosclerotic disease. Aims: This study aimed to measure serum resistin, IL-6 levels and lipid profile in nondiabetic controls, diabetics, and ischemic heart disease subjects with and without diabetes. Association between resistin and IL-6 was also determined. Materials & methods: In this comparative cross-sectional study, 147 subjects were selected, aged between 40 and 70 years. Subjects were divided into four groups as mentioned above. Plasma glucose was measured using the gluco-oxidase method. Lipid profile levels were measured using standard enzymatic methods. Levels of resistin and IL-6 were determined by ELISA. Results: Out of 147 patients, 36 were controls and 111 were cases. Serum resistin and IL-6 levels increased significantly in diabetics (23.4 ± 0.74 ng/ml and 73.1 ± 2.57 ng/ml, respectively) and nondiabetics with ischemic heart disease (14.1 ± 0.51 ng/ml and 66.2 ± 2.08 ng/ml, respectively) compared with diabetics and nondiabetic controls. Positive correlations were found between IL-6 and resistin, and a significant positive correlation was shown in ischemic heart disease groups (r = 0.659; p = 0.001). Conclusion: This study shows that the plasma resistin and IL-6 concentrations increased significantly in patients with ischemic heart disease with and without diabetes. This shows that there is a possible role of resistin and IL-6 in inflammatory processes, especially in atherosclerosis.

Food components with anti-obesity effect

Although many food components are reportedly beneficial to body-weight management, lack of understanding of molecular mechanisms and their function in overall adiposity under physiological conditions hinders successful and safe development of antiobesity functional foods. A positive energy balance resulting from an increase in food intake, a reduced energy expenditure, and/or dysfunction of adipose biology is associated with the development of obesity. This article provides an overview of the components involved in energy balance and adipose development and function. There is evidence that numerous ingredients found in foods can modulate energy balance and adipose biology, thereby potentially lowering adiposity.

Measurement of salivary resistin level in patients with type 2 diabetes

Serum resistin was initially hypothesized as a link between obesity and insulin resistance in mice. The latest evidence suggests that serum resistin is proinflammatory cytokines. Inflammation plays a key role in the pathogenesis of type 2 diabetes mellitus (T2DM). Many reports have previously identified changed serum resistin levels in patients with T2DM, but little is known of the levels of resistin in saliva. In our study, saliva and serum samples were collected from 38 patients with newly diagnosed T2DM at each time point of OGTT and 35 nondiabetic controls at fasting state. Resistin concentrations were measured using ELISA. We have demonstrated the presence of resistin in saliva of T2DM and nondiabetic subjects. Saliva resistin levels of T2DM are significantly higher than those of nondiabetic controls. Resistin levels in saliva are not affected by eating activity and correlated with serum resistin levels at any time points of OGTT. A positive correlation of serum and salivary resistin with BMI and HOMA-IR existed in T2DM. Measurement of resistin in saliva is a simple, noninvasive and may be an acceptable alternative to blood sampling for evaluatinginflammation/obesity/insulin resistance state.

Adipocytokines: The pied pipers

Even though there have been major advances in therapy, atherosclerosis and coronary artery disease retain their lead as one of the major causes of morbidity and mortality in the first decade of 21(st) century. To add to the woes, we have diabetes, obesity and insulin resistance as the other causes. The adipose tissue secretes several bioactive mediators that influence inflammation, insulin resistance, diabetes, atherosclerosis and several other pathologic states besides the regulation of body weight. These mediators are mostly proteins and are termed "adipocytokines". Adiponectin, resistin, visfatin, retinol binding protein-4 (RBP-4) and leptin are a few such proteins. Adiponectin is a multimeric protein, acting via its identified receptors, AdipoR1 and AdipoR2. It is a potential biomarker for metabolic syndrome and has several antiinflammatory actions. Adiponectin increases insulin sensitivity and ameliorates obesity. Resistin, another protein secreted by the adipose tissue, derived its name due to its involvement in the development of insulin resistance. It plays a role in the pathophysiology of several conditions because of its robust proinflammatory activity mediated through the activation of extracellular signal regulated kinases 1 and 2 (ERK 1/2). In 2007, resistin was reported to have protective effect in ischemia-reperfusion injury and myocyte-apoptosis in the setting of myocardial infarction (MI). RBP-4 is involved in the developmental pathology of type 2 diabetes mellitus and obesity. Visfatin has been described as an inflammatory cytokine. Increased expression of visfatin mRNA has been observed in inflammatory conditions like atherosclerosis and inflammatory bowel disease. Leptin mainly regulates the food intake and energy homeostasis. Leptin resistance has been associated with development of obesity and insulin resistance. Few drugs (thiazolidinediones, rimonabant, statins, etc.) and some lifestyle modifications have been found to improve the levels of adipocytokines. Their role in therapy has a lot in store to be explored upon.

Mouse resistin modulates adipogenesis and glucose uptake in 3T3-L1 preadipocytes through the ROR1 receptor

Mouse resistin, a cysteine-rich protein primarily secreted from mature adipocytes, is involved in insulin resistance and type 2 diabetes. Human resistin, however, is mainly secreted by immune mononuclear cells, and it competes with lipopolysaccharide for the binding to Toll-like receptor 4, which could mediate some of the well-known proinflammatory effects of resistin in humans. In addition, resistin has been involved in the regulation of many cell differentiation and proliferation processes, suggesting that different receptors could be involved in mediating its numerous effects. Thus, a recent work identifies an isoform of Decorin (Δ Decorin) as a functional resistin receptor in adipocyte progenitors that may regulate white adipose tissue expansion. Our work shows that the mouse receptor tyrosine kinase-like orphan receptor (ROR)1 could mediate some of the described functions of resistin in 3T3-L1 adipogenesis and glucose uptake. We have demonstrated an interaction of mouse resistin with specific domains of the extracellular region of the ROR1 receptor. This interaction results in the inhibition of ROR1 phosphorylation, modulates ERK1/2 phosphorylation, and regulates suppressor of cytokine signaling 3, glucose transporter 4, and glucose transporter 1 expression. Moreover, mouse resistin modulates glucose uptake and promotes adipogenesis of 3T3-L1 cells through ROR1. In summary, our results identify mouse resistin as a potential inhibitory ligand for the receptor ROR1 and demonstrate, for the first time, that ROR1 plays an important role in adipogenesis and glucose homeostasis in 3T3-L1 cells. These data open a new line of research that could explain important questions about the resistin mechanism of action in adipogenesis and in the development of insulin resistance.

Quantitative comparison of adipocytokine gene expression during adipocyte maturation in non-obese and obese rats

Adipocytokines secreted from adipocytes have been extensively analyzed due to their role as key factors in various complications of obesity, including arterial sclerosis, liver steatosis, insulin resistance, and diabetes. Several in vivo and in vitro studies have suggested that adipocyte maturation is related to fluctuations in adipocytokine secretion. However, the relationship between adipocyte maturation and adipocytokine levels has not been fully elucidated. Therefore, we sought to clarify the link between adipocytokine gene expression and adipocyte maturation through systematic analysis. We quantified mRNA for six adipocytokine genes: adiponectin, resistin, leptin, plasminogen activator inhibitor 1 (PAI-1), heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF), and visfatin, in adipose tissue, in primary cultured adipocytes obtained from an obese Zucker rat, and in the preadipocyte cell line 3T3-L1. Moreover, to elucidate the role of adipocytokines in adipocyte maturation, adipocytokine expression levels were analyzed during maturation. Although fluctuations in adipocytokine gene expression were heterogeneous, gene expression was highly similar during maturation of primary cultured adipocytes from obese and non-obese rats, suggesting that the maturation process is independent from processes that lead to obesity. Moreover, the expression patterns of adiponectin, resistin and leptin mRNA in 3T3-L1 cells were highly similar to those in primary cultured adipocytes, indicating that these adipocytokines could be common maturation markers for primary cultured adipocytes obtained from obese and non-obese rats, and for preadipocyte cell lines.

Adipokines: new emerging roles in fertility and reproduction

Adipose tissue is a specialized endocrine and paracrine organ producing specific factors called adipokines. It is well known that adipokines balance is fundamental to prevent obesity, metabolic syndrome, and cardiovascular diseases. During the last years, new roles of adipokines have been emerging in the field of fertility and reproduction. Although the literature is still quite controversial, this review serves to resume current knowledge on this topic. Alterations in adipokine levels or in their mechanism of action are associated with fertility impairment and pregnancy diseases, as well as with obesity, metabolic syndrome, and cardiovascular diseases. Normal levels of adipokines are fundamental to maintain integrity of hypothalamus-pituitary-gonadal axis, regular ovulatory processes, successful embryo implantation, and physiologic pregnancy. More efforts are needed to understand the mechanisms and to the extent to which adipokine changes are involved in the impairment of fertility and pregnancy outcome, to find possible medical treatments.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians Learning Objectives: After completion of this educational activity, the obstetrician/gynecologist should be better able to demonstrate current knowledge in the research field of adipokines in fertility and reproduction; evaluate the central role of metabolism balance in good pregnancy outcome; and apply new perspectives of studies.

Human resistin: found in translation from mouse to man

The discovery of resistin 10 years ago as a fat cell-secreted factor that modulates insulin resistance suggested a link to the current obesity-associated epidemics of diabetes and cardiovascular disease, which are major human health concerns. Although adipocyte-derived resistin is indisputably linked to insulin resistance in rodent models, the relevance of human resistin is complicated because human resistin is secreted by macrophages rather than adipocytes, and because of the descriptive nature of human epidemiology. In this review, we examine the recent and growing evidence that human resistin is an inflammatory biomarker and a potential mediator of diabetes and cardiovascular disease.

An isoform of decorin is a resistin receptor on the surface of adipose progenitor cells

Adipose stromal cells (ASCs) serve as mesenchymal progenitors in white adipose tissue (WAT). Intercellular interactions involving ASCs have remained obscure. By merging phage display technology with fluorescence-activated cell sorting (FACS), we screened a combinatorial library for peptides that target mouse ASCs in vivo. We isolated peptide CSWKYWFGEC that specifically homes to ASCs, used it as bait to purify the corresponding ASC surface receptor, and identified it as a previously unreported cleavage product of decorin (DCN) lacking the glycanation site (termed ΔDCN). We demonstrate that ΔDCN is differentially expressed on ASC surface. In a screen for ΔDCN-binding proteins, we identified resistin, an adipokine for which the receptor has been unknown. Expression of ΔDCN in 3T3-L1 cells promoted proliferation and migration but suppressed lipid accumulation upon adipogenesis induction, which was resistin dependent. We conclude that ΔDCN serves as a functional receptor of resistin in adipocyte progenitors and may regulate WAT expansion.

Lipid metabolism in mammalian tissues and its control by retinoic acid

Evidence has accumulated that specific retinoids impact on developmental and biochemical processes influencing mammalian adiposity including adipogenesis, lipogenesis, adaptive thermogenesis, lipolysis and fatty acid oxidation in tissues. Treatment with retinoic acid, in particular, has been shown to reduce body fat and improve insulin sensitivity in lean and obese rodents by enhancing fat mobilization and energy utilization systemically, in tissues including brown and white adipose tissues, skeletal muscle and the liver. Nevertheless, controversial data have been reported, particularly regarding retinoids' effects on hepatic lipid and lipoprotein metabolism and blood lipid profile. Moreover, the molecular mechanisms underlying retinoid effects on lipid metabolism are complex and remain incompletely understood. Here, we present a brief overview of mammalian lipid metabolism and its control, introduce mechanisms through which retinoids can impact on lipid metabolism, and review reported activities of retinoids on different aspects of lipid metabolism in key tissues, focusing on retinoic acid. Possible implications of this knowledge in the context of the management of obesity and the metabolic syndrome are also addressed. This article is part of a Special Issue entitled Retinoid and Lipid Metabolism.

Breast milk hormones and regulation of glucose homeostasis

Growing evidence suggests that a complex relationship exists between the central nervous system and peripheral organs involved in energy homeostasis. It consists in the balance between food intake and energy expenditure and includes the regulation of nutrient levels in storage organs, as well as in blood, in particular blood glucose. Therefore, food intake, energy expenditure, and glucose homeostasis are strictly connected to each other. Several hormones, such as leptin, adiponectin, resistin, and ghrelin, are involved in this complex regulation. These hormones play a role in the regulation of glucose metabolism and are involved in the development of obesity, diabetes, and metabolic syndrome. Recently, their presence in breast milk has been detected, suggesting that they may be involved in the regulation of growth in early infancy and could influence the programming of energy balance later in life. This paper focuses on hormones present in breast milk and their role in glucose homeostasis.

Resistin concentration is increased in the peritoneal fluid of women with endometriosis

PROBLEM

The aim of this study was to investigate the concentration of resistin and adiponectin in the peritoneal fluid (PF) of patients with endometriosis.

METHOD OF STUDY

PF sampling was obtained from women with (n = 48) and without endometriosis (n = 36), and the anthropometric indices of the patients were measured. Resistin and adiponectin concentrations in the PF were determined using the enzyme-linked immunosorbent assay.

RESULTS

The mean concentration of PF resistin was significantly higher in women with endometriosis compared to the controls. PF resistin concentrations were not associated with any of the anthropometric indices. The PF adiponectin did not differ between the two groups, but showed a significant association with the weight, body mass index, and hip circumference. After adjusting for these factors, PF adiponectin expression was not associated with endometriosis.

CONCLUSION

The findings of this study suggest a potent role for resistin in endometriosis. Further studies are needed to elucidate the biological implications of resistin in endometriosis.

Identification of the target proteins of rosiglitazone in 3T3-L1 adipocytes through proteomic analysis of cytosolic and secreted proteins

Rosiglitazone, one of the thiazolidinedione (TZD), is an oral antidiabetic drug that activates a gamma isoform of peroxisome proliferator-activated receptor (PPARγ). To identify target proteins induced by rosiglitazone in adipocytes, we first performed simultaneous in-depth proteomic profiling of cytosolic proteins and secreted proteins (secretome) from 3T3-L1 adipocytes using a label-free quantification method with nano-UPLC MS/MS. In total, we identified 646 proteins from 3T3-L1 adipocytes, of which 172 and 162 proteins were upregulated and downregulated >1.5-fold, respectively, in rosiglitazone-treated cells, as compared to controls. Some differentially expressed proteins in particular, including fatty acid translocase (FAT)/CD36, fatty acid binding protein, lipoprotein lipase, acetyl CoA acyltransferase, carnitine O-palmitoyltransferase 2, sterol carrier protein, adiponectin, and phosphoenolpyruvate carboxykinase could explain the current action mechanism of TZDs. Furthermore, this study is the first to report on two potential target proteins of rosiglitazone, such as adenomatosis polyposis coli 2 (APC2), and eukaryotic translation initiation factor 5A-1 (eIF5A) related to apoptosis and cell division. Our data clearly suggest that in-depth proteomic approaches using cytosolic and secreted proteins are important and necessary for identification of drug targets at the protein level.

Age-related autocrine diabetogenic effects of transgenic resistin in spontaneously hypertensive rats: gene expression profile analysis

Increased circulating levels of resistin have been proposed as a possible link between obesity and insulin resistance; however, many of the potential metabolic effects of resistin remain to be investigated, including systemic versus local resistin action. We investigated potential autocrine effects of resistin on lipid and glucose metabolism in 2- and 16-mo-old transgenic spontaneously hypertensive rats (SHR) expressing a nonsecreted form of mouse resistin under control of the aP2 promoter. To search for possible molecular mechanisms, we compared gene expression profiles in adipose tissue in 6-wk-old transgenic SHR versus control rats, before development of insulin resistance, by digital transcriptional profiling using high-throughput sequencing. Both young and old transgenic rats showed moderate expression of the resistin transgene in adipose tissue but had serum resistin levels similar to control SHR and undetectable levels of transgenic resistin in the circulation. Young transgenic rats exhibited mild glucose intolerance. In contrast, older transgenic rats displayed marked glucose intolerance in association with near total resistance of adipose tissue to insulin-stimulated glucose incorporation into lipids (6 ± 2 vs. 77 ± 19 nmol glucose·g(-1)·2 h(-1), P < 0.00001). Ingenuity Pathway Analysis of differentially expressed genes revealed calcium signaling, Nuclear factor-erythroid 2-related factor-2 (NRF2)-mediated oxidative stress response, and actin cytoskeletal signaling canonical pathways as those most significantly affected. Analysis using DAVID software revealed oxidative phosphorylation, glutathione metabolism, pyruvate metabolism, and peroxisome proliferator-activated receptor (PPAR) signaling as top Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. These results suggest that with increasing age autocrine effects of resistin in fat tissue may predispose to diabetes in part by impairing insulin action in adipose tissue.

Maternal serum resistin concentrations in gestational diabetes mellitus and normal pregnancies

AIM

To investigate changes in maternal serum resistin levels during pregnancy and postpartum and clarify their relationship to insulin resistance.

METHODS

Thirty normal pregnant women were compared to 30 women diagnosed with gestational diabetes mellitus (GDM). Serum resistin levels were collected at the time of glucose challenge test (26-28 weeks), at 38 gestational weeks and at the third postpartum day and measured with enzyme immunoassay. Correlation of resistin to the homeostatic model assessment-insulin resistance (HOMA-IR) was performed.

RESULTS

Maternal serum resistin levels at 38 weeks were significantly higher in pregnant women with GDM compared to the control group (0.28 vs 0.21 ng/mL, P = 0.02) and the same was true for the immediate puerperium (0.25 vs 0.19 ng/mL, P = 0.03). A significant increase in resistin levels was observed in GDM women from 26-28 weeks to 38 weeks (0.21 vs 0.28 ng/mL, P = 0.02), but not in controls. A decrease in serum resistin levels was noted in both the GDM and control groups, at 38 weeks and the immediate postpartum period, but this decrease did not reach statistical significance in either of the two groups. Resistin levels were positively correlated to HOMA-IR at 26-28 weeks of gestation (r = +0.253, P = 0.05).

CONCLUSION

GDM is associated with increased resistin serum levels in term pregnancy as well as postpartum. Resistin is positively correlated to HOMA-IR at 26-28 weeks of gestation. A reduction in maternal resistin after delivery indicates a significant placental or fetal contribution in the production of resistin.

Resistin is associated with mortality in patients with traumatic brain injury

INTRODUCTION

Recently, we reported that high levels of resistin are present in the peripheral blood of patients with intracerebral hemorrhage and are associated with a poor outcome. However, not much is known regarding the change in plasma resistin and its relation with mortality after traumatic brain injury (TBI). Thus, we sought to investigate change in plasma resistin level after TBI and to evaluate its relation with disease outcome.

METHODS

Fifty healthy controls and 94 patients with acute severe TBI were included. Plasma samples were obtained on admission and at days 1, 2, 3, 5 and 7 after TBI. Its concentration was measured by enzyme-linked immunosorbent assay.

RESULTS

Twenty-six patients (27.7%) died from TBI within 1 month. After TBI, plasma resistin level in patients increased during the 6-hour period immediately after TBI, peaked within 24 hours, plateaued at day 2, decreased gradually thereafter and was substantially higher than that in healthy controls during the 7-day period. A forward stepwise logistic regression selected plasma resistin level (odds ratio, 1.107; 95% confidence interval, 1.014-1.208; P = 0.023) as an independent predictor for 1-month mortality of patients. A multivariate linear regression showed that plasma resistin level was negatively associated with Glasgow Coma Scale score (t = -6.567, P < 0.001). A receiver operating characteristic curve identified plasma resistin cutoff level (30.8 ng/mL) that predicted 1-month mortality with the optimal sensitivity (84.6%) and specificity (75.0%) values (area under curve, 0.854; 95% confidence interval, 0.766-0.918; P < 0.001).

CONCLUSIONS

Increased plasma resistin level is found and associated with Glasgow Coma Scale score and mortality after TBI.

Cord blood resistin and adiponectin in term newborns of diabetic mothers

INTRODUCTION

Adipose tissue can release hormones into the blood stream in response to specific extracellular stimuli or changes in metabolic status. Resistin, an adipose-secreted factor, is primarily involved in the modulation of insulin sensitivity and adipocyte differentiation. Adiponectin, an adipocyte-specific hormone with insulin sensitizing, anti-inflammatory and anti-atherogenic effects, is reduced in obesity and type II diabetes. The aim of the study was to assess the influence of maternal pre-existing diabetes on cord blood resistin and adiponectin at birth in relation to neonatal anthropometric parameters and cord blood insulin levels.

MATERIAL AND METHODS

A total of 60 term newborns were prospectively enrolled and categorized into three groups: 20 were macrosomic infants of pre-gestational diabetic mothers (group I), 20 were non-macrosomic infants of pre-gestational diabetic mothers (group II) and 20 were healthy non-macrosomic infants born to non-diabetic mothers serving as controls (group III). Infants' anthropometric indices were recorded. Cord blood samples for glucose, insulin, resistin and adiponectin assay, together with maternal glycosylated haemoglobin were obtained.

RESULTS

Serum insulin was increased while resistin and adiponectin were significantly decreased in infants of diabetic mothers (IDMs) compared to the control group. Serum glucose, insulin, resistin and adiponectin were comparable in group I and II. Cord serum resistin correlated positively with cord blood glucose in IDMs in both macrosomic and non-macrosomic groups. Cord serum insulin correlated positively with triceps skinfold thickness in all studied neonates. Cord serum resistin and adiponectin showed no correlation with neonatal anthropometric indices. Multiple regression analysis demonstrated that insulin, resistin and adiponectin together were highly correlated with birth weight, with adiponectin as the one responsible for this positive correlation.

CONCLUSIONS

Infants of diabetic mothers had elevated levels of cord serum insulin and suppressed levels of cord serum resistin and adiponectin, suggesting that the regulation of these metabolic pathways is probably operational before birth. Levels were comparable in both macrosomic and non-macrosomic neonates.