Maternal serum level of resistin is associated with risk for gestational diabetes mellitus: A meta-analysis

The Placental Role in Gestational Diabetes Mellitus: A Molecular Perspective

During pregnancy, women undergo several metabolic changes to guarantee an adequate supply of glucose to the foetus. These metabolic modifications develop what is known as physiological insulin resistance. When this process is altered, however, gestational diabetes mellitus (GDM) occurs. GDM is a multifactorial disease, and genetic and environmental factors play a crucial role in its aetiopathogenesis. GDM has been linked to both macroscopic and molecular alterations in placental tissues that affect placental physiology. This review summarizes the role of the placenta in the development of GDM from a molecular perspective, including hormonal and pro-inflammatory changes. Inflammation and hormonal imbalance, the characteristics dominating the GDM microenvironment, are responsible for placental changes in size and vascularity, leading to dysregulation in maternal and foetal circulations and to complications in the newborn. In conclusion, since the hormonal mechanisms operating in GDM have not been fully elucidated, more research should be done to improve the quality of life of patients with GDM and their future children.

Programming of metabolism by adipokines during development

The intrauterine and early postnatal periods represent key developmental stages in which an organism is highly susceptible to being permanently influenced by maternal factors and nutritional status. Strong evidence indicates that either undernutrition or overnutrition during development can predispose individuals to disease later in life, especially type 2 diabetes mellitus and obesity, a concept known as metabolic programming. Adipose tissue produces important signalling molecules that control energy and glucose homeostasis, including leptin and adiponectin. In addition to their well-characterized metabolic effects in adults, adipokines have been associated with metabolic programming by affecting different aspects of development. Therefore, alterations in the secretion or signalling of adipokines, caused by nutritional insults in early life, might lead to metabolic diseases in adulthood. This Review summarizes and discusses the potential role of several adipokines in inducing metabolic programming through their effects during development. The identification of the endocrine factors that act in early life to permanently influence metabolism represents a key step in understanding the mechanisms behind metabolic programming. Thus, future strategies aiming to prevent and treat these metabolic diseases can be designed, taking into consideration the relationship between adipokines and the developmental origins of health and disease.

Effect of Lifestyle Interventions during Pregnancy on Maternal Leptin, Resistin and Offspring Weight at Birth and One Year of Life

Lifestyle during pregnancy impacts the health of the mother and child. However, the extent to which physical activity affects maternal biomarkers and factors that might influence birth weight remains unclear. We analysed data from two lifestyle interventions in which the effects of an exercise programme (2x/week, 60-90 min) on the course of pregnancy with regard to adipokines and offspring were evaluated. A total of 70 women participated in this study (45, intervention group; 25, control group). Anthropometric data and maternal fasting serum leptin and resistin levels were measured at three time points (approximately 14th (T1), 24th (T2), and 36th (T3) weeks of gestation). Neonatal/child data were retrieved from screening examinations. Independent of the intervention, we found a positive correlation between the fat mass at T1 and both leptin and resistin levels at all time points. Leptin level was significantly higher in the control group at T3; however, no differences between the groups were found for resistin. The birth weight was influenced by the birth length, fat mass at T1/T3, and resistin level at T2. The BMI-SDS at one year of age was influenced by maternal fat-free mass at T3 and resistin at T1/T2. Even if these results can only be interpreted cautiously, lifestyle interventions during pregnancy are important in promoting maternal and child health. Further randomised controlled trials and translational studies are warranted to clarify the underlying mechanisms.

Novel Biomolecules in the Pathogenesis of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is one of the most common metabolic diseases in pregnant women. Its early diagnosis seems to have a significant impact on the developing fetus, the course of delivery, and the neonatal period. It may also affect the later stages of child development and subsequent complications in the mother. Therefore, the crux of the matter is to find a biopredictor capable of singling out women at risk of developing GDM as early as the very start of pregnancy. Apart from the well-known molecules with a proven and clear-cut role in the pathogenesis of GDM, e.g., adiponectin and leptin, a potential role of newer biomolecules is also emphasized. Less popular and less known factors with different mechanisms of action include: galectins, growth differentiation factor-15, chemerin, omentin-1, osteocalcin, resistin, visfatin, vaspin, irisin, apelin, fatty acid-binding protein 4 (FABP4), fibroblast growth factor 21, and lipocalin-2. The aim of this review is to present the potential and significance of these 13 less known biomolecules in the pathogenesis of GDM. It seems that high levels of FABP4, low levels of irisin, and high levels of under-carboxylated osteocalcin in the serum of pregnant women can be used as predictive markers in the diagnosis of GDM. Hopefully, future clinical trials will be able to determine which biomolecules have the most potential to predict GDM.

Salivary resistin level and its association with insulin resistance in obese individuals

The escalating global burden of type 2 diabetes mellitus necessitates the implementation of strategies that are both more reliable and faster in order to improve the early identification of insulin resistance (IR) in high-risk groups, including overweight and obese individuals. The use of salivary biomarkers offers a promising alternative to serum collection because it is safer, more comfortable, and less painful to obtain saliva samples. As obesity is the foremost contributory factor in IR development, the adipocytokines such as leptin, adiponectin, resistin, and visfatin secreted from the adipose tissue have been studied as potential reliable biomarkers for IR. Measurement of salivary adipokines as predictors for IR has attracted widespread attention because of the strong correlation between their blood and salivary concentrations. One of the adipokines that is closely related to IR is resistin. However, there are conflicting findings on resistin’s potential role as an etiological link between obesity and IR and the reliability of measuring salivary resistin as a biomarker for IR. Hence this study reviewed the available evidence on the potential use of salivary resistin as a biomarker for IR in order to attempt to gain a better understanding of the role of resistin in the development of IR in obese individuals.

Resistin in pregnancy: Analysis of determinants in pairs of umbilical cord blood and maternal serum

Objective

Despite intensive research on the cytokine resistin only few studies investigated mother-newborn-pairs during healthy pregnancy and reported about interactions with clinical obstetric variables or other cytokines. Comparison of existing studies is difficult due to differences between assays, sample collection, gestational age, definition of healthy controls and patient characteristics. Furthermore, differences between rodent models and humans do not allow for a direct comparison.

Methods

In this cross-sectional, prospective study 109 healthy mother-newborn pairs were analyzed. Maternal venous blood samples were taken on admission to the labor ward; newborn venous blood samples were drawn from the placental part of the umbilical cord (UC), immediately after clamping. Resistin, leptin, adiponectin, TNF-α, IL-6 and brain derived neurotrophic factor (BDNF) serum concentrations were measured with commercially available immunoassays. Determinants of maternal and newborn resistin levels were analyzed using simple and multiple linear regression.

Results

UC resistin levels were higher than maternal concentrations (median 17.69 ng/mL, IQR 7.36 vs. median 8.04 ng/mL, IQR 4.30). Correlation between UC and maternal resistin levels was moderate (R = 0.503, p < 0.01). In multiple regression analysis levels of maternal resistin and newborn TNF-α remained significant determining factors for UC resistin levels. Gestational age and maternal BDNF-levels remained significant factors for maternal resistin levels.

Conclusion

In healthy, term newborns and their respective mothers a positive correlation between maternal and newborn levels and an association with gestational age around term can be found and point to a placental source of resistin. Further investigations are needed to clarify the possible contribution of transplacental transport of resistin into the fetal circulation. Except for gestational age most of the clinical obstetric variables tested do not seem to be determining factors for fetal or maternal resistin. Interactions of resistin with other cytokines like TNF-α and BDNF could be the missing link for the conflicting results in literature.

Saliva resistin as a screening marker of gestational diabetes mellitus

OBJECTIVE

The aim of this study was to evaluate the resistin concentrations in saliva; which is a noninvasive and stress-free diagnostic sample, and to investigate the significance of salivary resistin concentrations in screening GDM.

METHODS

This cross-sectional case-control study included 41 newly diagnosed GDM patients and 40 healthy pregnant. The participants were consecutively included in the study among eligible pregnant women; who were in the age range from 18 to 40 years of age and at the gestational age between 24 and 28 weeks. The levels of serum and salivary resistin were determined using an enzyme-linked immunosorbent assay method.

RESULTS

Maternal serum resistin and salivary resistin concentrations were significantly higher in the patients with GDM compared to the individuals in the control group. The data were evaluated by the receiver-operator curve analysis; which revealed that serum and saliva resistin concentrations were moderately successful markers to differentiate subjects with GDM from healthy pregnant women.

CONCLUSIONS

The results indicate that the determination of saliva resistin levels at the gestational age between 24 to 28 weeks may be used as an alternative, stress-free, and noninvasive technique that may be used in GDM screening.

Maternal circulating levels of Adipocytokines and insulin resistance as predictors of gestational diabetes mellitus: preliminary findings of a longitudinal descriptive study

Purpose

The present study aimed to assess the role of adipocytokines as predictive markers of gestational diabetes mellitus (GDM). We undertook this study to explore the association of adiponectin, resistin, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) and insulin resistance in the development of GDM.

Methods

This longitudinal descriptive study was done in the Medical College Hospital, involving the departments of Biochemistry and Gynecology. The study subjects were pregnant women with normal body mass index. They were recruited at 12-14 weeks of gestation, The healthy pregnant women were selected and were followed at 24-28 weeks for screening of GDM. The participants were categorized as healthy and GDM based on oral glucose tolerance test results. Blood samples were collected on both the occasions at 12-14 weeks and 24-28 weeks. The serum samples were analyzed for levels of insulin, adiponectin, resistin, IL-6 and TNF-alpha. Insulin resistance (HOMA-IR) was calculated from serum insulin and plasma glucose values.

Results

The levels of HOMA-IR, resistin, IL-6 and TNF-alpha were significantly higher and level of adiponectin was significantly lower in GDM subjects in comparison to healthy pregnant women, when compared both at 12 weeks and 24 weeks. The levels of resistin, IL-6 and TNF-alpha were significantly higher and level of adiponectin was lower at 24 weeks in comparison to 12 weeks, in the healthy pregnant women as well as those with GDM .

Conclusions

Significant difference in the levels of adipocytokines between the healthy and GDM pregnant women suggest potential clinical application of these molecules as biomarkers of GDM. The increase or decrease in the levels of adipocytokines during the course of pregnancy in GDM subjects suggests their role in GDM and potential use as predictive markers.

Fetal circulating human resistin increases in diabetes during pregnancy and impairs placental mitochondrial biogenesis

Background

Diabetes during pregnancy affects placental mitochondrial content and function, which has the potential to impact fetal development and the long-term health of offspring. Resistin is a peptide hormone originally discovered in mice as an adipocyte-derived factor that induced insulin resistance. In humans, resistin is primarily secreted by monocytes or macrophages. The regulation and roles of human resistin in diabetes during pregnancy remain unclear.

Methods

Fetal resistin levels were measured in cord blood from pregnancies with (n = 42) and without maternal diabetes (n = 81). Secretion of resistin from cord blood mononuclear cells (CBMCs) was measured. The actions of human resistin in mitochondrial biogenesis were determined in placental trophoblastic cells (BeWo cells) or human placental explant.

Results

Concentrations of human resistin in cord sera were higher in diabetic pregnancies (67 ng/ml) compared to healthy controls (50 ng/ml, P < 0.05), and correlated (r = 0.4, P = 0.002) with a measure of maternal glycemia (glucose concentration 2 h post challenge). Resistin mRNA was most abundant in cord blood mononuclear cells (CBMCs) compared with placenta and mesenchymal stem cells (MSCs). Secretion of resistin from cultured CBMCs was increased in response to high glucose (25 mM). Exposing BeWo cells or human placental explant to resistin decreased expression of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), mitochondrial abundance, and ATP production.

Conclusions

Resistin is increased in fetal circulation of infants exposed to the diabetic milieu, potentially reflecting a response of monocytes/macrophages to hyperglycemia and metabolic stresses associated with diabetes during pregnancy. Increased exposure to resistin may contribute to mitochondrial dysfunction and aberrant energy metabolism characteristic of offspring exposed to diabetes in utero.