Increased visfatin concentrations in women with gestational diabetes mellitus

Adipokines in pregnancy

Reproductive success consists of a sequential events chronology, starting with the ovum fertilization, implantation of the embryo, placentation, and cellular processes like proliferation, apoptosis, angiogenesis, endocrinology, or metabolic changes, which taken together finally conduct the birth of healthy offspring. Currently, many factors are known that affect the regulation and proper maintenance of pregnancy in humans, domestic animals, or rodents. Among the determinants of reproductive success should be distinguished: the maternal microenvironment, genes, and proteins as well as numerous pregnancy hormones that regulate the most important processes and ensure organism homeostasis. It is well known that white adipose tissue, as the largest endocrine gland in our body, participates in the synthesis and secretion of numerous hormones belonging to the adipokine family, which also may regulate the course of pregnancy. Unfortunately, overweight and obesity lead to the expansion of adipose tissue in the body, and its excess in both women and animals contributes to changes in the synthesis and release of adipokines, which in turn translates into dramatic changes during pregnancy, including those taking place in the organ that is crucial for the proper progress of pregnancy, i.e. the placenta. In this chapter, we are summarizing the current knowledge about levels of adipokines and their role in the placenta, taking into account the physiological and pathological conditions of pregnancy, e.g. gestational diabetes mellitus, preeclampsia, or intrauterine growth restriction in humans, domestic animals, and rodents.

Diurnal rythm of Nampt is gender and weight dependent

RESEARCH AIM

Nicotinamide phosphoribosyltransferase (Nampt) is an adipocytokine that is elevated in obesity, type 2 diabetes and increased levels are associated with inflammatory processes. Nampt serum concentrations have been suggested to follow a diurnal rhythm peaking in the afternoon in lean males. However, no data exists regarding the effects of gender and body weight.

MATERIAL AND METHODS

We measured Nampt serum levels over 24 h in a cohort of healthy individuals living with either normal weight or obesity. Furthermore, effects of meals, oral glucose tolerance test and physical exercise on Nampt concentrations were evaluated. Correlation analyses to other hormonal- and lab parameters and anthropometric measurements were performed.

RESULTS

Nampt showed a diurnal rhythm with increased levels at daytime and a peak in the early afternoon. This diurnal rhythm was significant for all groups but obese males. The Nampt amplitude, measured both relatively and absolutely, was significantly higher in females than in males. Meals did not influence Nampt serum levels, whereas physical exercise and an OGTT did significantly influence Nampt serum levels.

CONCLUSION

In conclusion, we found gender specific differences in Nampt amplitude and coefficient variation with both being higher in females. The circadian rhythm of Nampt was independent of gender in healthy lean individuals, whereas it was disturbed in men with obesity.

Extracellular nicotinamide phosphoribosyltransferase: role in disease pathophysiology and as a biomarker

Nicotinamide phosphoribosyltransferase (NAMPT) plays a central role in mammalian cell metabolism by contributing to nicotinamide adenine dinucleotide biosynthesis. However, NAMPT activity is not limited to the intracellular compartment, as once secreted, the protein accomplishes diverse functions in the extracellular space. Extracellular NAMPT (eNAMPT, also called visfatin or pre-B-cell colony enhancing factor) has been shown to possess adipocytokine, pro-inflammatory, and pro-angiogenic activities. Numerous studies have reported the association between elevated levels of circulating eNAMPT and various inflammatory and metabolic disorders such as obesity, diabetes, atherosclerosis, arthritis, inflammatory bowel disease, lung injury and cancer. In this review, we summarize the current state of knowledge on eNAMPT biology, proposed roles in disease pathogenesis, and its potential as a disease biomarker. We also briefly discuss the emerging therapeutic approaches for eNAMPT inhibition.

Serum visfatin as a metabolic biomarker in obese patients with gestational diabetes mellitus

BACKGROUND

Visfatin is an adipokine produced and secreted by the adipose tissue. It exerts an insulin-like effect by the insulin receptor-1 and has a hypoglycemic effect. We aimed to investigate how serum visfatin changes in women with gestational diabetes mellitus (GDM), and whether it is predictive of neonatal outcomes.

METHODS

Visfatin levels were prospectively measured in peripheral blood serum by enzyme immunoassay in 210 pregnant women, 156 of which were diagnosed with GDM, 18 of which suffered from pregnancy-induced hypertension (PIH) and 36 healthy controls.

RESULTS

Patients with obesity class II (median=2.562 ng/mL) and class III (median=6.2940 ng/mL) had higher serum visfatin than overweight patients (median=0.735 ng/mL); (Mann-Whitney U test, P=0.037 and P=0.023, respectively). In GDM patients with BMI above 30, serum visfatin was associated to glycosylated hemoglobin (Spearman correlation test, R=0.26, P=0.045). Women with BMI above 25 treated with insulin had lower serum visfatin levels than those treated with diet only (Mann-Whitney U test, P=0.045). No correlation was found between visfatin and parameters of lipid profile such as HDL, LDL, or triglycerides (Spearman correlation tests, R=-0.051, -0.1, 0.0019; P=0.54, 0.29, 0.98, respectively). We observed that visfatin was not associated with birth weight (Spearman correlation test, R=-0.014, P=0.86) or adverse neonatal outcome as measured by umbilical artery pH below 7.25 (Mann-Whitney U test, P=0.55) or Apgar score below 10 (Mann-Whitney U test, P=0.21).

CONCLUSIONS

In GDM patients with higher BMI, serum visfatin was elevated, correlated positively with glycosylated hemoglobin, and decreased upon treatment with insulin therapy.

Measuring visfatin levels in saliva: an alternative approach to gestational diabetes screening

Objective

Oral glucose tolerance testing (OGTT) is the current recommended approach for the diagnosis of gestational diabetes mellitus (GDM). Visfatin is a type of novel adipokine of interest that mostly participates in glucose metabolism and inflammatory processes. We aim to identify a screening technique for GDM using salivary visfatin levels and to establish this technique's value as a screening method compared to OGTT.

Methods

This is a cross-sectional case-control study. The cohort was formed from the saliva samples of pregnant patients in their 24^th through 28^th weeks of gestation. Patients were divided into two groups depending on their GDM status. OGTT and visfatin test results were compared and subjected to further analysis to establish a cutoff value for visfatin testing.

Results

ELISA results indicated a significant difference between patients with GDM compared to patients without GDM; the values were 18.89 ± 9.59 and 12.44 ± 8.75, respectively (p: 0.007). A cutoff value of 10.5 ng/mL can be used to detect GDM with 78% sensitivity and 51% specificity.

Conclusion

Salivary visfatin levels were significantly higher in patients with GDM. The existence of a differential in the concentration of visfatin in saliva can be utilized to develop a new screening method for GDM.

The Association Between Three Adipocytokines (Adiponectin, Resistin and Visfatin) And Thyroid Status in Patients With Type 2 Diabetes Mellitus and Autoimmune Thyroiditis

Autoimmune thyroiditis (AIT) and type 2 diabetes mellitus (DM2) are the most common endocrinological diseases worldwide. Relation between these diseases explains several hypotheses. One of them is influence of some adipocytokines. This study evaluated association between three adipocytokines (adiponectin, resistin and visfatin) and thyroid and glycid status in patients with DM2 and AIT compared to the control group (CG). The group consisted of four subgroups: patients with DM2 without thyreopathies, patients with AIT on substitution therapy without diabetes and prediabetes, patients with DM2 and AIT on substitution therapy and healthy subjects as the CG. We investigated parameters of thyroid and glucose metabolism and serum levels of three adipocytokines. The mean level of resistin in the group of patients with diabetes and thyroiditis was significantly higher than in patients with thyroiditis without diabetes and than in the CG. We found a weak negative correlation between visfatin and fasting glucose levels in patients with thyroiditis without diabetes. We detected a weak negative correlation between resistin and glycated haemoglobin and a weak negative correlation between visfatin and thyroid gland volume in patients with diabetes without thyroiditis. In the CG we determined a weak positive correlation between visfatin and free thyroxin. Our results are consistent with several studies, which confirmed association between AIT and adipocytokines.

Visfatin level and gestational diabetes mellitus: a systematic review and meta-analysis

It is reported that elevated visfatin level is associated with gestational diabetes mellitus (GDM). However, the relationship between visfatin level and GDM remains controversial. The aim of our study was to systematically review available literature linking visfatin to GDM for a comprehensive understanding of the relationship between circulating visfatin level and GDM in human. PubMed, The Cochrane Library and Web of Science were searched for studies published up to July 2020. Standard mean difference with 95% confidence interval was calculated to evaluate the relationship between visfatin level and GDM using the Review Manager 5.3 and Stata 12.0. The evidence indicated that no significant difference was observed in the level of circulating visfatin between the women with GDM and normal glucose tolerance, suggesting circulating visfatin level is not independently related to GDM. Nevertheless, visfatin is involved in the development of GDM in obese women.

The possible role of endocrine dysfunction of adipose tissue in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is diabetes that is first diagnosed in the second or third trimester of pregnancy in patients who did not have a history of diabetes before pregnancy. Consequences of GDM include increased risk of macrosomia and birth complications in the infant and an increased risk of maternal type 2 diabetes mellitus (T2DM) after pregnancy. There is also a longer-term risk of obesity, T2DM, and cardiovascular diseases in the child. GDM is the result of impaired glucose tolerance due to pancreatic β-cell dysfunction on a background of insulin resistance that physiologically increases during pregnancy. The strongest clinical predictors of GDM are overweight and obesity. The fact that women with GDM are more likely to be overweight or obese suggests that adipose tissue dysfunction may be involved in the pathogenesis of GDM, similarly to T2DM. Adipose tissue is not only involved in energy storage but also functions as an active endocrine organ secreting adipokines (specific hormones and cytokines) with the ability to alter insulin sensitivity. Recent evidence points to a crucial role of numerous adipokines produced by fat in the development of GDM. The following text summarizes the current knowledge about a possible role of selected adipokines in the development of GDM.

Nasser S, Younis N, Bhagani H, Al-Dhaheri Y, Pintus G, Eid AA, El-Yazbi AF, Eid AH. Visfatin: A Possible Role in Cardiovasculo-Metabolic Disorders

Visfatin/NAMPT (nicotinamide phosphoribosyltransferase) is an adipocytokine with several intriguing properties. It was first identified as pre-B-cell colony-enhancing factor but turned out to possess enzymatic functions in nicotinamide adenine dinucleotide biosynthesis, with ubiquitous expression in skeletal muscles, liver, cardiomyocytes, and brain cells. Visfatin exists in an intracellular (iNAMPT) and extracellular (eNAMPT) form. Intracellularly, visfatin/iNAMPT plays a regulatory role in NAD⁺ biosynthesis and thereby affects many NAD-dependent proteins such as sirtuins, PARPs, MARTs and CD38/157. Extracellularly, visfatin is associated with many hormone-like signaling pathways and activates some intracellular signaling cascades. Importantly, eNAMPT has been associated with several metabolic disorders including obesity and type 1 and 2 diabetes. In this review, a brief overview about visfatin is presented with special emphasis on its relevance to metabolic diseases. Visfatin/NAMPT appears to be a unique molecule with clinical significance with a prospective promising diagnostic, prognostic, and therapeutic applications in many cardiovasculo-metabolic disorders.

Association between circulating visfatin and pre-eclampsia: a systematic review and meta-analysis

OBJECTIVE

Pre-eclampsia (PE) is a serious pregnancy status characterized by high blood pressure. Although visfatin is usually associated with PE. Observational studies evaluating the relationship between circulating visfatin and pre-eclampsia have reported inconsistent results. We conducted this systematic review and meta-analysis to summarize published data on the association between visfatin and pre-eclampsia.

METHODS

Electronic databases PubMed, ISI web of science, EMBASE, Scopus and the Cochrane library were comprehensively searched for selection of eligible studies until January 5, 2020. A random-effects model and the generic inverse variance method were used for quantitative data synthesis. The assessment of study quality was performed using the e Newcastle-Ottawa scale and the Agency for Healthcare Research and Quality. Sensitivity analyses and prespecified subgroup were conducted to evaluate potential heterogeneity. Random-effects meta-regression was conducted to assess the impact of potential confounders on the estimated effect sizes. The protocol for this study was registered in PROSPERO (No. CRD42018105861) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Thirteen studies comprising a total of 536 subjects were included in this meta-analysis. We observed that the pre-eclampsia risk is associated with a statistically significant elevation of visfatin level [SMD (1.33 µg/l) (95% CI 0.37, 2.2) p = .007]. No significant publication bias was observed in the meta-analysis. Subgroup and sensitivity analyses indicated that the pooled effects size were affected by systolic blood pressure [SMD (1.82 µg/l) 95% CI (0.94, 2.7), p < .05], gestational age [SMD (2.01 µg/l) 95% CI (0.57, 3.4), p = .006], body mass index [SMD (1.6 µg/l) 95% CI (0.37, 3), p < .05] and pregnancy trimesters[SMD (2.3 µg/l) 95% CI (0.95, 3.7), p = .001]. Random-effects meta-regression showed a significant association of visfatin level with potential confounders including systolic blood pressure, gestational age and birth weight at delivery of pre-eclampsia patients.

CONCLUSIONS

Collectively, our data revealed that the increase of visfatin level can be associated with the risk of pre-eclampsia. However, further studies on pre-eclampsia populations are warranted for corroboration of our findings.

Can adipokine visfatin be a novel marker of pregnancy-related disorders in women with obesity?

Overweight and obesity have become a dangerous disease requiring multiple interventions, treatment and preventions. In women of reproductive age, obesity is one of the most common medical conditions. Among others, obese state is characterized by low-grade systemic inflammation and enhanced oxidative stress. Increased maternal body mass index might amplify inflammation and reactive oxygen species production, which is associated with unfavourable clinical outcomes that affect both mother and child. Intrauterine growth retardation, preeclampsia, or gestational diabetes mellitus are examples of the hampered maternal and foetoplacental unit interactions. Visfatin is the obesity-related adipokine produced mainly by the visceral adipose tissue. Visfatin affects glucose homeostasis, as well as the regulation of genes related to oxidative stress and inflammatory response. Here, we review visfatin interactions in pregnancy-related disorders linked to obesity. We highlight the possible predictive and prognostic value of visfatin in diagnostic strategies on gravidas with obesity.

Placental expressions and serum levels of adiponectin, visfatin, and omentin in GDM

AIMS

Adiponectin, visfatin, and omentin have been shown to be associated with insulin sensitivity and might have a role in the pathophysiology of gestational diabetes mellitus (GDM). This study aimed to (1) compare adiponectin, visfatin, and omentin mRNA expressions in placenta and their serum levels between normal pregnancy (NP) and GDM class A1 (GDMA1) pregnancy and (2) determine correlations between placental gene expressions as well as serum levels with maternal and neonatal clinical parameters in all, NP, and GDM subjects.

METHODS

NP subjects (n = 37), who had normal medical history during their pregnancies without diagnosis of any abnormalities and GDMA1 subjects (n = 37), who were diagnosed since they had antenatal care, were recruited when they were in labor with a gestational age of at least 34 weeks. Clinical parameters and serum adiponectin, visfatin, and omentin levels were measured in the delivery room.

RESULTS

GDMA1 subjects had higher serum visfatin and plasma glucose levels, but lower serum omentin levels (p  < 0.05 all) compared to controls, with comparable levels of placental adiponectin, visfatin, and omentin expressions, plasma insulin, and indices of insulin sensitivity and insulin resistance. Serum visfatin was negatively correlated with neonatal weight and length in the GDM group (p  < 0.05 all). Serum omentin was negatively correlated with pre-pregnancy body mass index and waist circumference only in the NP group (p  < 0.05 all). Serum adiponectin was negatively correlated with maternal age and HOMA-IR in the NP group (p  < 0.05 all) and with placental weight and serum omentin in the GDM group (p  < 0.05 all).

CONCLUSIONS

In conclusion, in GDMA1, increased serum visfatin, which has insulin-mimetic effect, might be associated with a compensatory mechanism that improves the impaired insulin function. Decreased serum omentin in GDMA1, which is normally found in visceral obesity, might lead to insulin resistance and contribute to the pathophysiology of GDM.

Involvement of Novel Adipokines, Chemerin, Visfatin, Resistin and Apelin in Reproductive Functions in Normal and Pathological Conditions in Humans and Animal Models

It is well known that adipokines are endocrine factors that are mainly secreted by white adipose tissue. Their central role in energy metabolism is currently accepted. More recently, their involvement in fertility regulation and the development of some reproductive disorders has been suggested. Data concerning the role of leptin and adiponectin, the two most studied adipokines, in the control of the reproductive axis are consistent. In recent years, interest has grown about some novel adipokines, chemerin, visfatin, resistin and apelin, which have been found to be strongly associated with obesity and insulin-resistance. Here, we will review their expression and role in male and female reproduction in humans and animal models. According to accumulating evidence, they could regulate the secretion of GnRH (Gonadotropin-Releasing Hormone), gonadotropins and steroids. Furthermore, their expression and that of their receptors (if known), has been demonstrated in the human and animal hypothalamo-pituitary-gonadal axis. Like leptin and adiponectin, these novel adipokines could thus represent metabolic sensors that are able to regulate reproductive functions according to energy balance changes. Therefore, after investigating their role in normal fertility, we will also discuss their possible involvement in some reproductive troubles known to be associated with features of metabolic syndrome, such as polycystic ovary syndrome, gestational diabetes mellitus, preeclampsia and intra-uterine growth retardation in women, and sperm abnormalities and testicular pathologies in men.

The role of adipokines in the pathogenesis of gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a complex condition whose physiopathology to date has not been completely clarified. Two major metabolic disorders, insulin resistance and β-cells dysfunction, play currently major role in pathogenesis of GDM. These elements are influenced by the amount of adipose tissue present before and/or during the pregnancy. Consequently, adipokines (adiponectin (APN), leptin (LPT), adipocyte fatty acid-binding protein, resistin, visfatin, omentin, vaspin, apelin, chemerin) secreted by adipose tissue, may contribute directly and/or indirectly, through the enhancement of chronic inflammation, aggravating insulin resistance and promoting GDM onset. This review aims to outline the potential physiopathological and prognostic role in GDM of adipokines, mainly APN and LPT.

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

INTRODUCTION

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

EVIDENCE ACQUISITION

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

EVIDENCE SYNTHESIS

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

CONCLUSIONS

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

Serum levels of adipokines in gestational diabetes: a systematic review

OBJECTIVE

To determine the difference of serum levels of 10 adipokines (apelin, chemerin, fatty acid-binding protein-4, fibroblast growth factor-21, monocyte chemoattractant protein-1, nesfatin-1, omentin-1, resistin, vaspin, and visfatin) among women with gestational diabetes and healthy pregnant controls.

MATERIALS AND METHODS

Literature search was conducted using the Medline (1966-2018), Scopus (2004-2018), Cochrane Central Register of Controlled Trials (CENTRAL) (1999-2018), Clinicaltrials.gov (2008-2018) and Google Scholar (2004-2018) databases, along with the reference list of the included studies.

RESULTS

Ninety-one studies were included in the present review, with a total number of 11,074 pregnant women. A meta-analysis was not conducted due to the high inter-study heterogeneity. Current evidence suggests that fatty acid-binding protein-4 levels are significantly increased in pregnancies complicated with gestational diabetes, while no association of serum apelin and monocyte chemoattractant protein-1 with the disease can be supported. Data regarding the rest adipokines are conflicting, since the available studies did not unanimously indicate a significant change of their levels in gestational diabetes.

CONCLUSIONS

The findings of the present systematic review suggest the promising role of fatty acid-binding protein-4 in the prediction of gestational diabetes, while inconsistent evidence exists regarding the rest novel adipokines. Future cohorts are needed to assess their predictive efficacy and fully elucidate their contribution in the disease.

The identification of gene signature and critical pathway associated with childhood-onset type 2 diabetes

In general, type 2 diabetes (T2D) usually occurs in middle-aged and elderly people. However, the incidence of childhood-onset T2D has increased all across the globe. Therefore, it is very important to determine the molecular and genetic mechanisms of childhood-onset T2D. In this study, the dataset GSE9006 was downloaded from the GEO (Gene Expression Omnibus database); it includes 24 healthy children, 43 children with newly diagnosed Type 1 diabetes (T1D), and 12 children with newly diagnosed T2D. These data were used for differentially expressed genes (DGEs) analysis and weighted co-expression network analysis (WGCNA). We identified 192 up-regulated genes and 329 down-regulated genes by performing DEGs analysis. By performing WGGNA, we found that blue module (539 genes) was highly correlated to cyan module (97 genes). Gene ontology (GO) and pathway enrichment analyses were performed to figure out the functions and related pathways of genes, which were identified in the results of DEGs and WGCNA. Genes with conspicuous logFC and in the high correlated modules were input into GeneMANIA, which is a plugin of Cytoscape application. Thus, we constructed the protein-protein interaction (PPI) network (92 nodes and 254 pairs). Eventually, we analyzed the transcription factors and references related to genes with conspicuous logFC or high-degree genes, which were present in both the modules of WGCNA and PPI network. Current research shows that EGR1 and NAMPT can be used as marker genes for childhood-onset T2D. Gestational diabetes and chronic inflammation are risk factors that lead to the development of childhood-onset T2D.

The Role of Inflammation in the Development of GDM and the Use of Markers of Inflammation in GDM Screening

Gestational diabetes mellitus is a hyperglycaemic state first recognised in pregnancy. GDM affects both mother and child. Women with GDM and their new-borns are at risk of developing type 2 diabetes in the future. The screening and diagnostic criteria for GDM are inconsistent and thus novel biomarkers of GDM are required to strengthen the screening and diagnostic processes in GDM. Chronic low-grade inflammation is linked to the majority of the well-established risk factors of GDM such as old age, obesity and PCOS. This review provides an overview of the present knowledge on the pathology of GDM, the screening criteria applied, the role of inflammation in the development of GDM and the use of markers of inflammation namely cytokines, oxidative stress markers, lipids, amino acids and iron markers in screening and diagnosis of GDM.

Association between circulating visfatin and gestational diabetes mellitus: a systematic review and meta-analysis

AIMS

Gestational diabetes mellitus (GDM) is a medical complication of any degree of glucose intolerance with onset or first recognition during pregnancy. Although visfatin is commonly considered to be related to GDM, studies revealed inconsistent results. This study aimed to clarify the relationship between visfatin and GDM.

METHODS

The protocol for this study was registered in PROSPERO (No. CRD42018086204) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). PubMed and Embase databases were used to search for relevant studies published up to September 30, 2017. The difference of visfatin levels between women with GDM and the controls was measured by standardised mean difference (SMD) and 95% confidence interval (CI).

RESULTS

Twenty-six studies that were published in 24 articles met the inclusion criteria, in which 2305 participants (1033 with GDM, mean age 31.39 years and 1272 controls, and mean age 29.99 years) were included. The quantitative meta-analysis revealed no significant difference in circulating visfatin levels between women with GDM and the controls (SMD = 0.249, 95% CI = - 0.079 to 0.576, P = 0.137). Subgroup analyses were performed referring to body mass index (BMI) where inconsistent results have been observed between cases and controls groups. For the ten studies, in which the level of BMI in women with GDM was higher than that in the control group, the pooled result showed that circulating visfatin was significantly higher among women with GDM than the controls (SMD = 0.367, 95% CI = 0.06 to 0.728, P = 0.046). Of other 16 studies BMI-matched, the pooled SMD illustrated no difference of visfatin.

CONCLUSIONS

Our study elucidates that visfatin is not independently associated with GDM. Visfatin is linked to GDM through maternal overweight/obesity, which is one of the major factors leading to the development of GDM.

The role of obesity and adipose tissue dysfunction in gestational diabetes mellitus

Gestational diabetes mellitus is defined as diabetes diagnosed in the second or third trimester of pregnancy in patients with no history of diabetes prior to gestation. It is the most common complication of pregnancy. The underlying pathophysiology shares some common features with type 2 diabetes mellitus (T2DM) combining relatively insufficient insulin secretion with increased peripheral insulin resistance. While a certain degree of insulin resistance is the physiological characteristics of the second half of pregnancy, it is significantly more pronounced in patients with gestational diabetes. Adipose tissue dysfunction and subclinical inflammation in obesity are well-described causes of increased insulin resistance in non-pregnant subjects and are often observed in individuals with T2DM. Emerging evidence of altered adipokine expression and local inflammation in adipose tissue in patients with gestational diabetes suggests an important involvement of adipose tissue in its etiopathogenesis. This review aims to summarize current knowledge of adipose tissue dysfunction and its role in the development of gestational diabetes. We specifically focus on the significance of alterations of adipokines and immunocompetent cells number and phenotype in fat. Detailed understanding of the role of adipose tissue in gestational diabetes may provide new insights into its pathophysiology and open new possibilities of its prevention and treatment.

Gestational diabetes from A to Z

Gestational diabetes mellitus (GDM) is defined as any degree of hyperglycaemia that is recognized for the first time during pregnancy. This definition includes cases of undiagnosed type 2 diabetes mellitus (T2DM) identified early in pregnancy and true GDM which develops later. GDM constitutes a greater impact on diabetes epidemic as it carries a major risk of developing T2DM to the mother and foetus later in life. In addition, GDM has also been linked with cardiometabolic risk factors such as lipid abnormalities, hypertensive disorders and hyperinsulinemia. These might result in later development of cardiovascular disease and metabolic syndrome. The understanding of the different risk factors, the pathophysiological mechanisms and the genetic factors of GDM, will help us to identify the women at risk, to develop effective preventive measures and to provide adequate management of the disease. Clinical trials have shown that T2DM can be prevented in women with prior GDM, by intensive lifestyle modification and by using pioglitazone and metformin. However, a matter of controversy surrounding both screening and management of GDM continues to emerge, despite several recent well-designed clinical trials tackling these issues. The aim of this manuscript is to critically review GDM in a detailed and comprehensive manner, in order to provide a scientific analysis and updated write-up of different related aspects.

The association between dysregulated adipocytokines in early pregnancy and development of gestational diabetes

BACKGROUND

To investigate the association of adipocytokines and other inflammatory markers with development of GDM.

METHODS

Serum adipocytokines and inflammatory markers were studied at 12 to 15 weeks gestation using biobanked control samples from a randomised trial. Study participants were identified as high risk for GDM using a validated clinical risk prediction tool. Markers were tested using commercial ELISA kits for high molecular weight (HMW) adiponectin, interleukin-6 (IL-6), plasminogen activator inhibitor-1, visfatin, omentin-1, sex-hormone binding globulin, monocyte chemoattractant protein, and asymmetrical dimethylarginine. The association between each biomarker and development of GDM at 24 to 28 weeks was evaluated using multivariable logistic regression analysis adjusted for maternal factors.

RESULTS

There were no differences in age, parity, country of birth, smoking, body mass index, or family history of diabetes in women with normal glucose tolerance (n = 78) and women who developed GDM (n = 25). Women with GDM were more likely to have a past history of GDM (P = 0.004). HMW adiponectin (odds ratio OR 0.37 [95% confidence interval 0.19-0.74]), omentin-1 (0.97 [0.94-0.99]), and IL-6 (1.87[1.03-3.37]) were associated with development of GDM, after adjustment for maternal age, body mass index, and past history of GDM. The other markers were not associated with GDM development.

CONCLUSIONS

Decreased high molecular weight adiponectin and omentin-1 and increased IL-6 may enhance sensitivity of early risk prediction tools for women at high risk of GDM. This may allow early identification and opportunities for prevention of GDM and adverse outcomes. Further research is required in large validation studies to confirm these results.

Are adipokines associated with gestational diabetes mellitus?

OBJECTIVE

To investigate the association of maternal serum levels of chemerin, retinol binding protein-4 (RBP-4), and visfatin with gestational diabetes mellitus (GDM).

MATERIAL AND METHODS

158 pregnant women were screened between 24 and 28 weeks of gestation. They were divided into two groups: GDM group (n=76) and control group (n=82). Maternal serum concentrations of chemerin, RBP-4, visfatin, insulin, and homeostasis model assessment-insulin resistance (HOMA-IR) were assessed.

RESULTS

There were no differences in age and gestational age between the GDM group and the control group (p=0.058 and p=0.820, respectively). Body mass index (BMI) at 24 to 28 weeks of gestation was higher in the GDM group (p<0.001). The serum concentrations of RBP-4, chemerin, and visfatin did not demonstrate significant differences between the GDM and control groups (p=0.871, p=0.100, and p=0.886, respectively). Significant differences in serum level of insulin and HOMA-IR were found between the GDM and control groups (14.94 vs 9.87, p<0.001 and 3.73 vs 1.77, p<0.001, respectively). Correlation analyses of chemerin, RBP-4, visfatin, insulin, and HOMA-IR in both groups revealed a weak degree of positive correlation between RBP-4 and chemerin (Spearman r=0.251, p=0.026) and a strong positive correlation between maternal insulin and HOMA (Spearman r=0.868, p<0.001).

CONCLUSION

No differences were found in serum chemerin, RBP-4, and visfatin between pregnant women with GDM and healthy pregnant women. Further prospective studies will be essential to elucidate the contribution of adipokines to GDM and the positive correlation between maternal RBP-4 and chemerin.

Monomeric eNAMPT in the development of experimental diabetes in mice: a potential target for type 2 diabetes treatment

AIMS/HYPOTHESIS

Serum extracellular nicotinamide phosphoribosyltransferase (eNAMPT) concentrations are elevated in type 2 diabetes. However, the relationship between abnormally elevated serum eNAMPT and type 2 diabetes pathophysiology is unclear. eNAMPT circulates in functionally and structurally distinct monomeric and dimeric forms. Dimeric eNAMPT promotes NAD biosynthesis. The role of eNAMPT-monomer is unclear but it may have NAD-independent proinflammatory effects. However, studies of eNAMPT in type 2 diabetes have not distinguished between monomeric and dimeric forms. Since type 2 diabetes is characterised by chronic inflammation, we hypothesised a selective NAD-independent role for eNAMPT-monomer in type 2 diabetes.

METHODS

Two mouse models were used to examine the role of eNAMPT-monomer in type 2 diabetes; (1) a mouse model of diabetes fed a high-fat diet (HFD) for 10 weeks received i.p. injections with an anti-monomeric-eNAMPT antibody; and (2) lean non-diabetic mice received i.p. injections with recombinant monomeric eNAMPT daily for 14 days.

RESULTS

Serum monomeric eNAMPT levels were elevated in HFD-fed mouse models of diabetes, whilst eNAMPT-dimer levels were unchanged. eNAMPT-monomer neutralisation in HFD-fed mice resulted in lower blood glucose levels, amelioration of impaired glucose tolerance (IGT) and whole-body insulin resistance, improved pancreatic islet function, and reduced inflammation. These effects were maintained for at least 3 weeks post-treatment. eNAMPT-monomer administration induced a diabetic phenotype in mice, characterised by elevated blood glucose, IGT, impaired pancreatic insulin secretion and the presence of systemic and tissue inflammation, without changes in NAD levels.

CONCLUSIONS/INTERPRETATION

We demonstrate that elevation of monomeric-eNAMPT plays an important role in the pathogenesis of diet-induced diabetes via proinflammatory mechanisms. These data provide proof-of-concept evidence that the eNAMPT-monomer represents a potential therapeutic target for type 2 diabetes.

Adipokine Serum visfatin level in pregnancy induced hypertension and uncomplicated pregnancy

BACKGROUND AND OBJECTIVES

Hypertensive disorder in pregnancy is the significant disease that badly affects the maternal and fetal prognosis and lead to higher mortality and morbidity in the prenatal period. Visfatin, potentially a new adipokine has emerged having high contribution in pathogenesis of pre-eclampsia. The objective of the study was to find the level of Visfatin in pregnancy induced hypertension and normal pregnant women.

METHODS

This study was carried out in tertiary care hospitals, Peshawar from March-October 2014. A total of 234 pregnant women (gestational age >20 weeks) were included in the study with distribution as Preeclampsia (PE=86), Eclampsia (E=74) and control (N=74). Blood was taken for measuring Visfatin level by Enzyme Linked Immunosorbent Assay (ELISA) technique. SPSS version 19 was used for statistical analysis. Student's t test was performed to evaluate the mean differences in patients and control.

RESULTS

Serum level of visfatin was significantly higher in pregnancy induced hypertension when compared with control (P value<0.001).: Comparisons of mean value of visfatin with age group of 21-40 years, body mass index (BMI), primary parous and parity 2-4, gestational age of >36 weeks and both systolic and diastolic blood pressure were highly significant in pregnancy induced hypertension when compared with control (p value<0.001).

CONCLUSION

Pregnancy induced hypertensive women showed increased level of serum Visfatin than normal pregnant women.

Characterization of visceral and subcutaneous adipose tissue transcriptome in pregnant women with and without spontaneous labor at term: implication of alternative splicing in the metabolic adaptations of adipose tissue to parturition

OBJECTIVE

The aim of this study was to determine gene expression and splicing changes associated with parturition and regions (visceral vs. subcutaneous) of the adipose tissue of pregnant women.

STUDY DESIGN

The transcriptome of visceral and abdominal subcutaneous adipose tissue from pregnant women at term with (n=15) and without (n=25) spontaneous labor was profiled with the Affymetrix GeneChip Human Exon 1.0 ST array. Overall gene expression changes and the differential exon usage rate were compared between patient groups (unpaired analyses) and adipose tissue regions (paired analyses). Selected genes were tested by quantitative reverse transcription-polymerase chain reaction.

RESULTS

Four hundred and eighty-two genes were differentially expressed between visceral and subcutaneous fat of pregnant women with spontaneous labor at term (q-value <0.1; fold change >1.5). Biological processes enriched in this comparison included tissue and vasculature development as well as inflammatory and metabolic pathways. Differential splicing was found for 42 genes [q-value <0.1; differences in Finding Isoforms using Robust Multichip Analysis scores >2] between adipose tissue regions of women not in labor. Differential exon usage associated with parturition was found for three genes (LIMS1, HSPA5, and GSTK1) in subcutaneous tissues.

CONCLUSION

We show for the first time evidence of implication of mRNA splicing and processing machinery in the subcutaneous adipose tissue of women in labor compared to those without labor.

The potential role of biomarkers in predicting gestational diabetes

Gestational diabetes (GD) is a frequent complication during pregnancy and is associated with maternal and neonatal complications. It is suggested that a disturbing environment for the foetus, such as impaired glucose metabolism during intrauterine life, may result in enduring epigenetic changes leading to increased disease risk in adult life. Hence, early prediction of GD is vital. Current risk prediction models are based on maternal and clinical parameters, lacking a strong predictive value. Adipokines are mainly produced by adipocytes and suggested to be a link between obesity and its cardiovascular complications. Various adipokines, including adiponectin, leptin and TNF&, have shown to be dysregulated in GD. This review aims to outline biomarkers potentially associated with the pathophysiology of GD and discuss the role of integrating predictive biomarkers in current clinical risk prediction models, in order to enhance the identification of those at risk.

Nicotinamide phosphoribosyltransferase leukocyte overexpression in Graves' opthalmopathy

To investigate the role of NAMPT/visfatin in euthyroid patients with Graves' disease without (GD) and with Graves' ophthalmopathy (GO), we analyzed NAMPT leukocyte expression and its serum concentration. This was a single-center, cross-sectional study with consecutive enrollment. In total, 149 patients diagnosed with Graves' disease were enrolled in the study. We excluded subjects with hyper- or hypothyroidism, diabetes mellitus, other autoimmune disorders, active neoplastic disease, and infection. The control group was recruited among healthy volunteers adjusted for age, sex, and BMI with normal thyroid function and negative thyroid antibodies. Serum levels of visfatin, TSH, FT4, FT3, antibodies against TSH receptor (TRAb), antithyroperoxidase antibodies, antithyroglobulin antibodies, fasting glucose, and insulin were measured. NAMPT mRNA leukocyte expression was assessed using RT-qPCR. NAMPT/visfatin serum concentration was higher in GD (n = 44) and GO (n = 49) patients than in the control group (n = 40) (p = 0.0275). NAMPT leukocyte expression was higher in patients with GO (n = 30) than in GD patients (n = 27) and the control group (n = 29) (p < 0.0001). Simple linear regression analysis revealed that NAMPT/visfatin serum concentration was significantly associated with GD (β = 1.5723; p = 0.021). When NAMPT leukocyte expression was used as a dependent variable, simple regression analysis found association with TRAb, fasting insulin level, HOMA-IR, GD, and GO. In the stepwise multiple regression analysis, we confirmed the association between higher serum NAMPT/visfatin level and GD (coefficient = 1.5723; p = 0.0212), and between NAMPT leukocyte expression and GO (coefficient = 2.4619; p = 0.0001) and TRAb (coefficient = 0.08742; p = 0.006). Increased NAMPT leukocyte expression in patients with GO might suggest a presently undefined role in the pathogenesis of GO.

The effect of Ramadan fasting on sirtuin and visfatin levels

OBJECTIVE

Our aim was to determine how Ramadan fasting effects serum Human NAD-dependent deacetylase sirtuin 1 (SIRT1/SIR2L1) and visfatin levels during pregnancy.

MATERIALS AND METHODS

Thirty-six patients were included in this case-control study. The patient group consisted of 18 pregnant women who were Ramadan fasting. Another healthy 18 pregnant women with matching pregnancy weeks and ages formed the control group. Blood samples were obtained from the patients for biochemical analyses and serum adipokine level measurements.

RESULTS

The mean sirtuin and visfatin levels in fasting pregnant women were 2.87 ± 0.95 and 60.18 ± 19.49 ng/mL, respectively, while the mean serum sirtuin and visfatin levels in the control group was determined to be 4.28 ± 1.45 and 23.26 ± 6.18 ng/mL, respectively. A statistically significant difference was determined between the groups (p = 0.002, p = 0.0001). A correlation analysis provided a negative correlation between number of fasting days and sirtuin levels (r = 0.45, p = 0.005) and a positive correlation with visfatin levels (r = 0.73, p = 0.0001).

CONCLUSION

As a result, while the serum sirtuin 1 level of pregnant women decreased due to fasting in Ramadan, we determined that their visfatin levels increased and this increase was in correlation with the days of fasting.

Expression of visfatin in the diabetic rat retina

BACKGROUND

Visfatin has been found in adipose tissue, liver and kidney of healthy and diabetic people, with its expression being increased in the aforementioned tissues in diabetes. Based on the former researches, visfatin may exist in the retina and affect the development of diabetic retinopathy. The expression of visfatin in Sprague-Dawley rats' retina, which may carve a path to study the pathogenesis of diabetic retinopathy, was investigated by this study.

METHODS

The mRNA and protein expression of visfatin in Sprague-Dawley rats' retina were detected by the reverse transcription-polymerase chain reaction (RT-PCR) and western blot. Immunohistochemical staining was applied to detect the expression location of visfatin in the rats' retinas.

RESULTS

The mRNA and visfatin protein expressions in both normal and streptozocin-induced diabetic rats' retina increased significantly in 2 to 8 weeks of diabetes mellitus (DM). Compared with the normal control groups, the difference was statistically significant (P < 0.05). The histological examination showed that the retinal thickness decreased gradually over the course of DM and the decrease in the outer nuclear layer was the most obvious. At 4 and 8 weeks, the decrease in the retinal thickness was significant (P < 0.01). Visfatin was expressed in the retinal nerve fibre layer, inner plexiform layer and outer plexiform layer, and with the progression of DM, its expression was increased.

CONCLUSIONS

Visfatin was expressed in the rats' retinas, mainly in the retinal nerve fibre layer, inner plexiform layer and outer plexiform layer. As the development of DM course, its expression was gradually increased.

Characterization of Visceral and Subcutaneous Adipose Tissue Transcriptome and Biological Pathways in Pregnant and Non-Pregnant Women: Evidence for Pregnancy-Related Regional-Specific Differences in Adipose Tissue

Objective

The purpose of this study was to compare the transcriptome of visceral and subcutaneous adipose tissues between pregnant and non-pregnant women.

Study Design

The transcriptome of paired visceral and abdominal subcutaneous adipose tissues from pregnant women at term and matched non-pregnant women (n = 11) was profiled with the Affymetrix Human Exon 1.0 ST array. Differential expression of selected genes was validated with the use of quantitative reverse transcription–polymerase chain reaction.

Results

Six hundred forty-four transcripts from 633 known genes were differentially expressed (false discovery rate (FDR) <0.1; fold-change >1.5), while 42 exons from 36 genes showed differential usage (difference in FIRMA scores >2 and FDR<0.1) between the visceral and subcutaneous fat of pregnant women. Fifty-six known genes were differentially expressed between pregnant and non-pregnant subcutaneous fat and three genes in the visceral fat. Enriched biological processes in the subcutaneous adipose tissue of pregnant women were mostly related to inflammation.

Conclusion

The transcriptome of visceral and subcutaneous fat depots reveals pregnancy-related gene expression and splicing differences in both visceral and subcutaneous adipose tissue. Furthermore, for the first time, alternative splicing in adipose tissue has been associated with regional differences and human parturition.

Insights into the molecular mechanisms of diabetes-induced endothelial dysfunction: focus on oxidative stress and endothelial progenitor cells

Diabetes mellitus is a heterogeneous, multifactorial, chronic disease characterized by hyperglycemia owing to insulin insufficiency and insulin resistance (IR). Recent epidemiological studies showed that the diabetes epidemic affects 382 million people worldwide in 2013, and this figure is expected to be 600 million people by 2035. Diabetes is associated with microvascular and macrovascular complications resulting in accelerated endothelial dysfunction (ED), atherosclerosis, and cardiovascular disease (CVD). Unfortunately, the complex pathophysiology of diabetic cardiovascular damage is not fully understood. Therefore, there is a clear need to better understand the molecular pathophysiology of ED in diabetes, and consequently, better treatment options and novel efficacious therapies could be identified. In the light of recent extensive research, we re-investigate the association between diabetes-associated metabolic disturbances (IR, subclinical inflammation, dyslipidemia, hyperglycemia, dysregulated production of adipokines, defective incretin and gut hormones production/action, and oxidative stress) and ED, focusing on oxidative stress and endothelial progenitor cells (EPCs). In addition, we re-emphasize that oxidative stress is the final common pathway that transduces signals from other conditions-either directly or indirectly-leading to ED and CVD.

The role of visfatin (PBEF/Nampt) in pregnancy complications

Visfatin (PBEF/Nampt) is an adipocytokine that exerts pleiotropic effects within the human body, particularly affecting its metabolism and immunity. Visfatin was originally identified as being secreted by peripheral blood lymphocytes acting as a pre-B-cell colony-enhancing factor (PBEF). However, it was subsequently reported to be expressed in almost every tissue of the human body, with visceral fat deposits being the main source of visfatin. In addition to its secreted form, visfatin may also be found intracellularly where it functions as a nicotinamide phosphoribosyltransferase (Nampt). Visfatin maternal plasma concentrations increase during pregnancy, suggesting its important role in this complicated process. Alterations in visfatin level also take place in patients during pregnancy complications. This review focuses on the ones that most commonly occur in connection with visfatin: preterm labor, pre-eclampsia and gestational diabetes mellitus. The review aims to provide a better understanding of the role of visfatin during pregnancy and the causes of its alteration in maternal plasma, highlighting the potential use of visfatin as a diagnostic marker of pregnancy complications in the future.

Correlations of serum visfatin and metabolisms of glucose and lipid in women with gestational diabetes mellitus

Aims/Introduction

Visfatin is a newly discovered adipocytokine hormone, which exerts an insulin‐like effect by binding to the insulin receptor‐1. However, the role of visfatin in human gestational diabetes mellitus (GDM) remains controversial. The purpose of the present study was to investigate the correlation between serum visfatin and metabolism of glucose and lipid in GDM.

Materials and Methods

This was a prospective study. A total of 38 GDM patients and 35 age‐ and body mass index‐matched controls were studied between January 2012 and October 2013. Fasting serum levels of visfatin, fasting plasma glucose, hemoglobin A1c and lipid profile were measured. Two‐tailed t‐tests and Pearson's correlation coefficient were used to analyze the data.

Results

Perinatal visfatin levels were negatively correlated with fasting plasma glucose, insulin resistance index and triglycerides in controls (r = −0.47, −0.51, −0.57, respectively; P < 0.05), and positively correlated with high‐density lipoprotein cholesterol (r = 0.32, P < 0.05). A positive correlation with visfatin level only appeared in weight gain and body mass index in women with GDM (r = 0.36, 0.45, respectively; P < 0.05).

Conclusions

Visfatin appears to be involved in glucose and lipid metabolism regulation and insulin resistance, suggesting a role in GDM pathogenesis.

Inflammatory and Other Biomarkers: Role in Pathophysiology and Prediction of Gestational Diabetes Mellitus

Understanding pathophysiology and identifying mothers at risk of major pregnancy complications is vital to effective prevention and optimal management. However, in current antenatal care, understanding of pathophysiology of complications is limited. In gestational diabetes mellitus (GDM), risk prediction is mostly based on maternal history and clinical risk factors and may not optimally identify high risk pregnancies. Hence, universal screening is widely recommended. Here, we will explore the literature on GDM and biomarkers including inflammatory markers, adipokines, endothelial function and lipids to advance understanding of pathophysiology and explore risk prediction, with a goal to guide prevention and treatment of GDM.

Cord blood chemerin: differential effects of gestational diabetes mellitus and maternal obesity

OBJECTIVE

Chemerin is a novel adipokine implicated in inflammation and obesity. We hypothesized that foetal chemerin would be elevated in gestational diabetes mellitus (GDM) and correlate with foetal and maternal adiposity.

DESIGN

Observational, longitudinal study.

SUBJECTS AND MEASUREMENTS

Foetal chemerin was measured separately in arterial and venous cord blood of 30 infants born to mothers with (n = 15) and without GDM (n = 15), in their mothers in early third trimester and at delivery and in amniotic fluid (week 32) of women with GDM. Expression of chemerin and its receptor in human foetal tissues commercially available and in placental cells was measured by quantitative PCR. Associations between foetal and maternal anthropometric and metabolic variables were assessed in multivariate regression models.

RESULTS

In GDM, foetal arterial but not venous cord blood chemerin levels were elevated by about 60% (P < 0·05). Venous cord blood chemerin was higher in infants of obese women (P < 0·01). In multivariate analyses, neither amniotic fluid nor cord blood chemerin levels correlated with birth weight or ponderal index. Both arterial and venous chemerin levels were related to maternal chemerin at birth, and arterial chemerin was associated with GDM status in addition. Maternal levels were unaltered in GDM, but higher in maternal obesity. Foetal liver produces fourfold more chemerin mRNA than other foetal tissues, whereas its receptor prevails in spleen.

CONCLUSIONS

Based on multivariate analyses, foetal growth appears unrelated to foetal chemerin. Maternal obesity and GDM have differential effects on foetal chemerin levels. Site of major production (liver) and action (spleen) differ in human foetal tissues.

Maternal leptin, adiponectin, resistin, visfatin and tumor necrosis factor-alpha in normal and gestational diabetes

Gestational diabetes mellitus (GDM) is a common medical complication associated with pregnancy. The present study evaluates the changes in maternal adipocytokines (leptin, adiponectin, resistin, visfatin and tumor necrosis factor-alpha; TNF-α) in pregnancy complicated with GDM compared to normal pregnancy at 2nd and 3rd trimesters. The study included total number of 142 pregnant women classified into 4 groups: normal pregnancy (n = 33) and pregnancy with GDM (n = 24) both at 2nd trimester and normal pregnancy (n = 38) and GDM (n = 47) at 3rd trimester. Both GDM groups were significantly presented with elevated body mass index, fasting blood sugar and abnormal oral glucose tolerance test compared to their matched control. Results indicated reduction in maternal serum leptin and adiponectin in GDM compared to normal pregnancy at 3rd trimester. Elevated resistin and TNF-α were evident among pregnancy complicated with GDM at both tested trimesters. On the other hand, significant elevation in maternal visfatin was noted between GDM and matched control at 2nd trimester only. Significant increase in maternal leptin and visfatin and resistin was noted by advances in gestational period in healthy pregnancy. On the other hand, reduced adiponectin and elevated visfatin mean values were noticed in GDM at 3rd compared to 2nd trimester. It could be concluded that increased insulin resistance accompanies GDM is associated with suppressed leptin and adiponectin and increased resistin and TNF-α which might suggest their involvement in the development of GDM.

Pre-B cell colony enhancing factor (PBEF), a cytokine with multiple physiological functions

Pre-B cell colony enhancing factor (PBEF) is regarded as a proinflammatory cytokine. Named for its first discovered function as a pre-B cell colony enhancing factor, it has since been found to have many other functions relating to cell metabolism, inflammation, and immune modulation. It has also been found to have intracellular and extracellular forms, with the two overlapping in function. Most of the intracellular functions of PBEF are due to its role as a nicotinamide phosphoribosyltransferase (Nampt). It has been found in human endothelial cells, where it is able to induce angiogenesis through upregulation of VEGF and VEGFR and secretion of MCP-1. In human umbilical endothelial cells, PBEF increases levels of the protease MMP 2/9. PBEF has also been found in a variety of immune cells other than B cells and has been shown to inhibit apoptosis of macrophages. Extracellular PBEF has been shown to increase inflammatory cytokines, such as TNF-α, IL-1β, IL-16, and TGF-β1, and the chemokine receptor CCR3. PBEF also increases the production of IL-6, TNF-α, and IL-1β in CD14(+) monocyctes, macrophages, and dendritic cells, enhances the effectiveness of T cells, and is vital to the development of both B and T lymphocytes. The purpose of this review is to summarize the recent advances in PBEF research.

Potential mechanisms of exercise in gestational diabetes

Gestational diabetes mellitus (GDM) is defined as glucose intolerance first diagnosed during pregnancy. This condition shares same array of underlying abnormalities as occurs in diabetes outside of pregnancy, for example, genetic and environmental causes. However, the role of a sedentary lifestyle and/or excess energy intake is more prominent in GDM. Physically active women are less likely to develop GDM and other pregnancy-related diseases. Weight gain in pregnancy causes increased release of adipokines from adipose tissue; many adipokines increase oxidative stress and insulin resistance. Increased intramyocellular lipids also increase cellular oxidative stress with subsequent generation of reactive oxygen species. A well-planned program of exercise is an important component of a healthy lifestyle and, in spite of old myths, is also recommended during pregnancy. This paper briefly reviews the role of adipokines in gestational diabetes and attempts to shed some light on the mechanisms by which exercise can be beneficial as an adjuvant therapy in GDM. In this regard, we discuss the mechanisms by which exercise increases insulin sensitivity, changes adipokine profile levels, and boosts antioxidant mechanisms.

Expression and regulation of nampt in human islets

Nicotinamide phosphoribosyltransferase (Nampt) is a rate-limiting enzyme in the mammalian NAD+ biosynthesis of a salvage pathway and exists in 2 known forms, intracellular Nampt (iNampt) and a secreted form, extracellular Nampt (eNampt). eNampt can generate an intermediate product, nicotinamide mononucleotide (NMN), which has been reported to support insulin secretion in pancreatic islets. Nampt has been reported to be expressed in the pancreas but islet specific expression has not been adequately defined. The aim of this study was to characterize Nampt expression, secretion and regulation by glucose in human islets. Gene and protein expression of Nampt was assessed in human pancreatic tissue and isolated islets by qRT-PCR and immunofluorescence/confocal imaging respectively. Variable amounts of Nampt mRNA were detected in pancreatic tissue and isolated islets. Immunofluorescence staining for Nampt was found in the exocrine and endocrine tissue of fetal pancreas. However, in adulthood, Nampt expression was localized predominantly in beta cells. Isolated human islets secreted increasing amounts of eNampt in response to high glucose (20 mM) in a static glucose-stimulated insulin secretion assay (GSIS). In addition to an increase in eNampt secretion, exposure to 20 mM glucose also increased Nampt mRNA levels but not protein content. The secretion of eNampt was attenuated by the addition of membrane depolarization inhibitors, diazoxide and nifedipine. Islet-secreted eNampt showed enzymatic activity in a reaction with increasing production of NAD+/NADH over time. In summary, we show that Nampt is expressed in both exocrine and endocrine tissue early in life but in adulthood expression is localized to endocrine tissue. Enzymatically active eNampt is secreted by human islets, is regulated by glucose and requires membrane depolarization.

Adipocytokines and insulin resistance across various degrees of glucose tolerance in pregnancy

OBJECTIVE

Gestational diabetes mellitus is characterized by progressive insulin resistance. Adipocytokines are thought to be associated with insulin resistance. This cross-sectional study evaluated the associations between serum concentrations of several adipocytokines and insulin resistance at different stages of glucose tolerance in pregnancy, using the homeostasis model assessment of insulin resistance (HOMA-IR) as a reference.

METHODS

According to oral glucose tolerance test results, 74 pregnant women were divided into three groups: normal glucose tolerance (n = 25); intermediate glucose tolerance (n = 19); gestational diabetes mellitus (n = 30). Adiponectin, leptin, resistin, visfatin and retinol-binding protein 4 (RBP4) concentrations were measured using enzyme-linked immuno sorbent assays.

RESULTS

Groups were comparable regarding age, week of gestation and body mass index before gestation. There were statistically significant between-group differences in HOMA-IR, but no significant differences regarding serum adipocytokine concentrations.

CONCLUSIONS

Adipo nectin, leptin, resistin, visfatin and RBP4 were not associated with the degree of glucose tolerance in pregnancy. Concentrations of these adipocytokines are not sufficiently sensitive to replace HOMA- IR in pregnancy.

Chemerin is present in human cord blood and is positively correlated with birthweight

OBJECTIVE

Chemerin, a novel adipokine, has been implicated in adipogenesis, inflammation, and metabolism. The aims of this study were to determine the presence of chemerin in cord blood and its association with birthweight.

STUDY DESIGN

This cross-sectional study included the following: (1) twins with (n = 24) or without (n = 28) birthweight discordancy; and (2) singletons subclassified into small-for-gestational-age (SGA; n = 18); appropriate for gestational age (AGA; n = 33); and large-for-gestational-age (LGA; n = 8). Cord blood chemerin was determined. Parametric and nonparametric statistics were used for analysis.

RESULTS

The results of the study included the following: (1) within the discordant twins group, the median chemerin concentration was significantly lower in the SGA group than in their cotwins; (2) within singletons, the median chemerin concentration was significantly higher in the LGA than the AGA newborns; and (3) the regression model revealed that chemerin was independently associated with birthweight.

CONCLUSION

Cord blood chemerin is present in cord blood and its concentrations are positively correlated with birthweight. These novel findings support a role of adipokines in fetal growth.

Changes in visfatin levels after oral glucose tolerance test in women with gestational diabetes mellitus

Visfatin levels increased following an oral glucose tolerance test (OGTT) in normal pregnancy, and this increase correlated with metabolic indexes such as blood glucose, blood fat, and insulin resistance. Conversely, visfatin levels in women with gestational diabetes mellitus (GDM) increased to lesser extent than in normal pregnancy, which suggests a disorder in the relationship between visfatin, blood glucose and insulin.

Maternal serum visfatin at 11-13 weeks' gestation in preeclampsia

The objective of this study was to determine if the maternal serum levels of visfatin in the first trimester of pregnancy are altered in cases that develop preeclampsia (PE) and whether the levels are related to placental perfusion reflected in uterine artery pulsatility index (PI). Serum visfatin and uterine artery PI were measured at 11(+0)-13(+6) weeks in 80 cases that developed PE and 240 unaffected controls. The median visfatin and uterine artery PI multiple of the unaffected median (MoM) in the outcome groups was compared and the significance of the association between visfatin MoM and uterine artery PI MoM, birth weight percentile and gestation at delivery was determined. In the PE group, compared with controls, there was a significantly higher median visfatin MoM (1.35, interquartile range (IQR): 0.69-2.16 vs 1.00, IQR: 0.55-1.96, P=0.027) and uterine artery PI MoM (1.19, IQR: 0.95-1.44 vs 1.03, IQR: 0.83-1.22, P<0.0001). In the PE group, there was no significant association between serum visfatin MoM and uterine artery PI MoM (P=0.589), gestation at delivery (P=0.763) or birth weight percentile (P=0.646). Serum visfatin levels at 11-13 weeks are increased in women who develop PE by a mechanism unrelated to impaired placental perfusion.