Expressions of irisin and urotensin II and their relationships with blood pressure in patients with preeclampsia

Urotensin II receptor deficiency ameliorates ligation-induced carotid intimal hyperplasia partially through the RhoA-YAP1 pathway

Intimal hyperplasia (IH) is a common pathological feature of vascular proliferative diseases, such as atherosclerosis and restenosis after angioplasty. Urotensin II (UII) and its receptor (UTR) are widely expressed in cardiovascular tissues. However, it remains unclear whether the UII/UTR system is involved in IH. Right unilateral common carotid artery ligation was performed and maintained for 21 days to induce IH in UTR knockout (UTR-/-) and wild-type (WT) mice. Histological analysis revealed that compared with WT mice, UTR-deficient mice exhibited a decreased neointimal area, angiostenosis and intima-media ratio. Immunostaining revealed fewer smooth muscle cells (SMCs), endothelial cells and macrophages in the lesions of UTR-/- mice than in those of WT mice. Protein interaction analysis suggested that the UTR may affect cell proliferation by regulating YAP and its downstream target genes. In vitro experiments revealed that UII can promote the proliferation and migration of SMCs, and western blotting also revealed that UII increased the protein expression of RhoA, CTGF, Cyclin D1 and PCNA and downregulated p-YAP protein expression, while these effects could be partly reversed by urantide. To evaluate the translational value of UTRs in IH management, WT mice were also treated with two doses of urantide, a UTR antagonist, to confirm the benefit of UTR blockade in IH progression. A high dose of urantide (600 μg/kg/day), rather than a low dose (60 μg/kg/day), successfully improved ligation-induced IH compared with that in mice receiving vehicle. The results of the present study suggested that the UII/UTR system may regulate IH partly through the RhoA-YAP signaling pathway.

Hydrogen Sulfide and Irisin, Potential Allies in Ensuring Cardiovascular Health

Irisin is a myokine secreted under the influence of physical activity and exposure to low temperatures and through different exogenous stimuli by the cleavage of its precursor, fibronectin type III domain-containing protein 5 (FNDC5). It is mainly known for maintaining of metabolic homeostasis, promoting the browning of white adipose tissue, the thermogenesis process, and glucose homeostasis. Growing experimental evidence suggests the possible central role of irisin in the regulation of cardiometabolic pathophysiological processes. On the other side, hydrogen sulfide (H2S) is well recognized as a pleiotropic gasotransmitter that regulates several homeostatic balances and physiological functions and takes part in the pathogenesis of cardiometabolic diseases. Through the S-persulfidation of cysteine protein residues, H2S is capable of interacting with crucial signaling pathways, exerting beneficial effects in regulating glucose and lipid homeostasis as well. H2S and irisin seem to be intertwined; indeed, recently, H2S was found to regulate irisin secretion by activating the peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)/FNDC5/irisin signaling pathway, and they share several mechanisms of action. Their involvement in metabolic diseases is confirmed by the detection of their lower circulating levels in obese and diabetic subjects. Along with the importance of metabolic disorders, these modulators exert favorable effects against cardiovascular diseases, preventing incidents of hypertension, atherosclerosis, heart failure, myocardial infarction, and ischemia-reperfusion injury. This review, for the first time, aims to explore the role of H2S and irisin and their possible crosstalk in cardiovascular diseases, pointing out the main effects exerted through the common molecular pathways involved.

The emerging roles of irisin in vascular calcification

Vascular calcification is a common accompanying pathological change in many chronic diseases, which is caused by calcium deposition in the blood vessel wall and leads to abnormal blood vessel function. With the progress of medical technology, the diagnosis rate of vascular calcification has explosively increased. However, due to its mechanism's complexity, no effective drug can relieve or even reverse vascular calcification. Irisin is a myogenic cytokine regulating adipose tissue browning, energy metabolism, glucose metabolism, and other physiological processes. Previous studies have shown that irisin could serve as a predictor for vascular calcification, and protect against hypertension, diabetes, chronic kidney disease, and other risk factors for vascular calcification. In terms of mechanism, it improves vascular endothelial dysfunction and phenotypic transformation of vascular smooth muscle cells. All the above evidence suggests that irisin plays a predictive and protective role in vascular calcification. In this review, we summarize the association of irisin to the related risk factors for vascular calcification and mainly explore the role of irisin in vascular calcification.

Serum irisin levels are negatively associated with blood pressure in dialysis patients

Elevated blood pressure is highly prevalent among dialysis patients and is associated with high mortality. Irisin is a newly found myokine that has been indicated to be related to blood pressure regulation in animal experiments. Data regarding the effect of serum irisin levels on blood pressure in dialysis patients are limited. To identify the association between serum irisin levels and blood pressure and examine determinant factors of systolic blood pressure in dialysis patients, we recruited 300 dialysis patients at Xuanwu Hospital Capital Medical University. Serum irisin levels were assessed by enzyme-linked immunosorbent assay kits. Blood pressure was self-measured on 7 consecutive days by an automated sphygmomanometer. The Pearson correlation test showed that the natural logarithm of irisin was negatively correlated with systolic blood pressure (r = -0.462, P < 0.001) and pulse pressure (r = -0.487, P < 0.001), but not correlated with diastolic blood pressure (r = -0.022, P = 0.709). Multivariate analysis revealed that the natural logarithm of irisin (β = -0.336, P < 0.001), lean tissue mass (β = 0.164, P = 0.005), diabetes mellitus (β = 0.165, P = 0.003) and serum calcium (β = -0.135, P = 0.019) were significant determinant factors for systolic blood pressure. This study is the first to demonstrate that serum irisin levels are significantly negatively associated with blood pressure in dialysis patients. Further studies are needed to provide possible mechanisms. We demonstrated that serum irisin levels were negatively associated with blood pressure in dialysis patients, which may provide a new target for antihypertensive treatment.

Physical exercise for a healthy pregnancy: the role of placentokines and exerkines

Complications such as diabetes and preeclampsia can occur during pregnancy. Moderate-intensity exercise can prevent such complications by releasing placentokines and exerkines, such as apelin, adiponectin, leptin, irisin, and chemerin. Exercise and apelin increase thermogenesis and glucose uptake in pregnancy by activating AMPK, PI3K, PGC-1α, AKT1, UCP3, and sarcolipin. Exercise increases apelin levels to reduce preeclampsia symptoms by increasing eNOS, NO, placental growth factor (PlGF), and VEGF and decreasing levels of fms-like tyrosine kinase 1 (sFlt-1), soluble endoglin (sEng), and oxidative stress. A negative relationship has been reported between plasma leptin and VO2peak/kg and VO2peak in women with gestational diabetes. In active women, decreases in leptin levels reduce the risk of preeclampsia by ~ 40%. Higher adiponectin levels are associated with greater physical activity and lead to increased insulin sensitivity. Increased adiponectin levels in preeclampsia and exercise counteract inflammatory and atherogenic activities while also having vascular protective effects. Exercise increases irisin levels that correlate negatively with fasting glucose, insulin concentration, and glycosylated hemoglobin levels. Irisin augments mRNA expression levels of UCP1 and cell death-inducing DNA fragmentation factor-like effector A (cidea) to cause browning of adipose tissue, increased thermogenesis, and increased energy consumption. Irisin concentrations in mothers with preeclampsia in the third trimester negatively correlate with systolic and diastolic blood pressure. Expression levels of chemerin, IL-6, and TNF-α are increased in gestational diabetes, and the increases in chemerin in late pregnancy positively correlate with the ratio of sFlt-1 to PlGF as a marker of preeclampsia. The effects of physical exercise on placentokines and exerkines in women at various stages of pregnancy remain poorly understood.

Preeclampsia and Obesity-The Preventive Role of Exercise

Obesity is now recognized as a worldwide epidemic. An inadequate diet and reduced physical activity are acknowledged as the leading causes of excess body weight. Despite growing evidence that obesity is a risk factor for unsuccessful pregnancies, almost half of all women who become pregnant today are overweight or obese. Common complications of pregnancy in this group of women are preeclampsia and gestational hypertension. These conditions are also observed more frequently in women with excessive weight gain during pregnancy. Preeclampsia is one of the most serious pregnancy complications with an unpredictable course, which in its most severe forms, threatens the life and health of the mother and her baby. The early identification of the risk factors for preeclampsia development, including obesity, allows for the implementation of prophylaxis and a reduction in maternal and fetal complications risk. Additionally, preeclampsia and obesity are the recognized risk factors for developing cardiovascular disease in later life, so prophylaxis and treating obesity are paramount for their prevention. Thus, a proper diet and physical activity might play an essential role in the prophylaxis of preeclampsia in this group of women. Limiting weight gain during pregnancy and modifying the metabolic risk factors with regular physical exercise creates favorable metabolic conditions for pregnancy development and benefits the elements of the pathogenetic sequence for preeclampsia development. In addition, it is inexpensive, readily available and, in the absence of contraindications to its performance, safe for the mother and fetus. However, for this form of prevention to be effective, it should be applied early in pregnancy and, for overweight and obese women, proposed as an essential part of planning pregnancy. This paper aims to present the mechanisms of the development of hypertension in pregnancy in obese women and the importance of exercise in its prevention.

Irisin, an Effective Treatment for Cardiovascular Diseases?

Irisin, as one of the myokines induced by exercise, has attracted much attention due to its important physiological functions such as white fat browning, the improvement in metabolism, and the alleviation of inflammation. Despite the positive role that irisin has been proven to play in the prevention and treatment of cardiovascular diseases, whether it can become a biomarker and potential target for predicting and treating cardiovascular diseases remains controversial, given the unreliability of its detection methods, the uncertainty of its receptors, and the species differences between animals and humans. This paper was intended to review the role of irisin in the diagnosis and treatment of cardiovascular diseases, the potential molecular mechanism, and the urgent problems to be solved in hopes of advancing our understanding of irisin as well as providing data for the development of new and promising intervention strategies by discussing the causes of contradictory results.

Maternal serum irisin levels in normotensive and preeclamptic pregnancies: a systematic review and meta-analysis

BACKGROUND

Altered irisin levels have been reported in pregnancy-associated disorders, such as preeclampsia.

OBJECTIVE

A systematic review and meta-analysis were conducted to evaluate the changes in maternal circulatory irisin levels in preeclampsia as compared to normotensive healthy pregnant controls.

METHODS

Relevant studies were identified by searching PubMed and other databases. Random-effects model was used to obtain standardized mean differences (SMDs) and its 95% confidence intervals (CIs). The sub-group meta-regression analyses were conducted to explore heterogeneity. The presence of publication bias and the study robustness was tested using funnel plot and sensitivity analyses, respectively.

RESULTS

This meta-analysis finally included 14 observations from eight studies. Compared with controls, preeclampsia patients showed significantly decreased serum irisin levels (SMD: -1.13; 95% CI: -1.63 to -0.62, p < .0001). The sub-group analysis showed that this decrease in irisin is regardless of body mass index (BMI) and gestational age of preeclampsia patients. The meta-regression analysis indicated that blood pressure is significantly associated with the observed results. There was no significant publication bias as indicated by the funnel plot analysis followed by Begg's (p = .35) and Egger's tests (p = .39). The sensitivity analysis indicated that no single study had a significant influence on the overall outcome, suggesting the robustness of this meta-analysis.

CONCLUSIONS

This meta-analysis showed significantly decreased maternal serum irisin level in preeclampsia patients as compared to normotensive pregnant women. This study highlights the need for future studies evaluating the diagnostic utilities and associations of irisin with the fetal and neonatal outcomes in preeclampsia.

The Emerging Role of Irisin in Cardiovascular Diseases

Irisin, a novel hormone like polypeptide, is cleaved and secreted by an unknown protease from a membrane‐spanning protein, FNDC5 (fibronectin type III domain‐containing protein 5). The current knowledge on the biological functions of irisin includes browning white adipose tissue, regulating insulin use, and anti‐inflammatory and antioxidative properties. Dysfunction of irisin has shown to be involved in cardiovascular diseases such as hypertension, coronary artery disease, myocardial infarction, and myocardial ischemia–reperfusion injury. Moreover, irisin gene variants are also associated with cardiovascular diseases. In this review, we discuss the current knowledge on irisin‐mediated regulatory mechanisms and their roles in the pathogenesis of cardiovascular diseases.

Irisin Protects the Human Placenta from Oxidative Stress and Apoptosis via Activation of the Akt Signaling Pathway

Irisin is a newly discovered exercise-mediated polypeptide hormone. Irisin levels increase during pregnancy however, women with preeclampsia (PE) have significantly lower levels of Irisin compared to women of healthy pregnancies. Even though many studies suggest a role of Irisin in pregnancy, its function in the human placenta is unclear. In the current study, we aimed to understand key roles of Irisin through its ability to protect against apoptosis is the preeclamptic placenta and in ex vivo and in vitro models of hypoxia/re-oxygenation (H/R) injury. Our studies show that Irisin prevents cell death by reducing pro-apoptotic signaling cascades, reducing cleavage of PARP to induce DNA repair pathways and reducing activity of Caspase 3. Irisin caused an increase in the levels of anti-apoptotic BCL2 to pro-apoptotic BAX and reduced ROS levels in an in vitro model of placental ischemia. Furthermore, we show that Irisin treatment acts through the Akt signaling pathway to prevent apoptosis and enhance cell survival. Our findings provide a novel understanding for the anti-apoptotic and pro-survival properties of Irisin in the human placenta under pathological conditions. This work yields new insights into placental development and disease and points towards intervention strategies for placental insufficiencies, such as PE, by protecting and maintaining placental function through inhibiting hypoxic ischemia-induced apoptosis.

Fibronectin type III domain-containing 5 in cardiovascular and metabolic diseases: a promising biomarker and therapeutic target

Cardiovascular and metabolic diseases are the leading causes of death and disability worldwide and impose a tremendous socioeconomic burden on individuals as well as the healthcare system. Fibronectin type III domain-containing 5 (FNDC5) is a widely distributed transmembrane glycoprotein that can be proteolytically cleaved and secreted as irisin to regulate glycolipid metabolism and cardiovascular homeostasis. In this review, we present the current knowledge on the predictive and therapeutic role of FNDC5 in a variety of cardiovascular and metabolic diseases, such as hypertension, atherosclerosis, ischemic heart disease, arrhythmia, metabolic cardiomyopathy, cardiac remodeling, heart failure, diabetes mellitus, and obesity.

Prenatal exercise in fetal development: a placental perspective

Maternal obesity (MO) and gestational diabetes mellitus (GDM) are common in Western societies, which impair fetal development and predispose offspring to metabolic dysfunction. Placenta is the organ linking the mother to her fetus, and MO suppresses the development of vascular system and expression of nutrient transporters in placenta, thereby affecting fetal development. For maintaining its proper physiological function, placenta is energy demanding, which is met through extensive oxidative phosphorylation. However, the oxidative capacity of placenta is suppressed due to MO and GDM. Recently, several studies showed that physical activity during pregnancy enhances oxidative metabolism and improves placental function, which might be partially mediated by exerkines, referring to cytokines elicited by exercise. In addition, as an endocrine organ, placenta secretes cytokines, termed placentokines, including apelin, superoxide dismutase 3, irisin, and adiponectin, which mediate fetal development and maternal metabolism. Possible molecular mechanisms linking maternal exercise and placentokines to placental and fetal development are further discussed. As an emerging field, up to now, available studies are limited, mostly conducted in rodents. Given the epidemics of obesity and metabolic disorders, as well as the prevalence of maternal sedentary lifestyle, the effects of exercise of pregnant women on placental function and placentokine secretion, as well as their impacts on fetal development, need to be further examined.

Role of Irisin in Myocardial Infarction, Heart Failure, and Cardiac Hypertrophy

Irisin is a myokine derived from the cleavage of fibronectin type III domain-containing 5. Irisin regulates mitochondrial energy, glucose metabolism, fatty acid oxidation, and fat browning. Skeletal muscle and cardiomyocytes produce irisin and affect various cardiovascular functions. In the early phase of acute myocardial infarction, an increasing irisin level can reduce endothelial damage by inhibiting inflammation and oxidative stress. By contrast, higher levels of irisin in the later phase of myocardial infarction are associated with more cardiovascular events. During different stages of heart failure, irisin has various influences on mitochondrial dysfunction, oxidative stress, metabolic imbalance, energy expenditure, and heart failure prognosis. Irisin affects blood pressure and controls hypertension through modulating vasodilatation. Moreover, irisin can enhance vasoconstriction via the hypothalamus. Because of these dual effects of irisin on cardiovascular physiology, irisin can be a critical therapeutic target in cardiovascular diseases. This review focuses on the complex functions of irisin in myocardial ischemia, heart failure, and cardiac hypertrophy.

Lifestyle interventions for the prevention and treatment of hypertension

Hypertension affects approximately one third of the world's adult population and is a major cause of premature death despite considerable advances in pharmacological treatments. Growing evidence supports the use of lifestyle interventions for the prevention and adjuvant treatment of hypertension. In this Review, we provide a summary of the epidemiological research supporting the preventive and antihypertensive effects of major lifestyle interventions (regular physical exercise, body weight management and healthy dietary patterns), as well as other less traditional recommendations such as stress management and the promotion of adequate sleep patterns coupled with circadian entrainment. We also discuss the physiological mechanisms underlying the beneficial effects of these lifestyle interventions on hypertension, which include not only the prevention of traditional risk factors (such as obesity and insulin resistance) and improvements in vascular health through an improved redox and inflammatory status, but also reduced sympathetic overactivation and non-traditional mechanisms such as increased secretion of myokines.

Maternal irisin level in last trimester isolated intrauterine growth-restriction

PURPOSE

Intrauterine Growth Restriction (IUGR) is the inability of the fetus to achieve the biologically accessible growth potential. Irisin is a recently discovered adipomyokine with a crucial role in energy metabolism. Our current study aimed to investigate the relationship between the isolated IUGR in the third trimester and maternal serum irisin level.

MATERIALS AND METHODS

This prospective case-control study included total 137 pregnant women who were between the 24th and 39th gestational weeks and who applied to the University of Health Sciences, Ankara Zekai Tahir Burak Women's Health Training and Research Center, between 2016 October-2017 May. The Study Group consisted of 68 pregnant women who were diagnosed with Isolated IUGR with Estimated Fetal Weight (EFW) <10th percentile. The Control Group consisted of 69 low-risk uncomplicated pregnant women, matched with the Study Group in terms of gestational week, and with EFW between 10th and 90th percentiles. Demographic data, clinical findings, fetal Doppler parameters, and obstetric-neonatal outcomes were evaluated. Maternal serum irisin levels were measured by ELISA (Enzyme-Linked Immunosorbent Assay) Method and compared between the groups.

RESULTS

Maternal serum irisin level was found to be significantly lower in IUGR Group as compared to the Control (3.83 ng/ml vs. 4.78 ng/ml, p < .001, respectively). There was a positive correlation between maternal serum irisin level and duration of pregnancy, the weight gain during pregnancy, birth weight, fetal abdominal circumference measurement and cerebroplacental ratio (r = 0.18, p = .03; r = 0.17, p = .04; r = 0.37, p < .001; r = 0.35, p < .001; r = 0.27, p = .001, respectively). Binary Logistic Regression Analysis showed that maternal serum irisin level is an independent estimator of IUGR [OR %95 CI: 8.33 (3.22 - 25.01)]. AUC (Area Under the Curve) analysis of maternal irisin for IUGR estimation was 0.75 (p < .001, 95% CI = 0.67 - 0.82). The optimal cutoff value was below 3.86 ng/ml for maternal irisin level with a sensitivity of 54.41% and a specificity of 88.41%, positive predictive value of 82.22% and negative predictive value of 66.30%.

CONCLUSION

Low level of maternal serum irisin in pregnancies with isolated IUGR was consistent with the role of irisin in metabolic pathways and with the increased risk of metabolic diseases in the future life of IUGR fetuses and their mothers.

The role of serum adipokine levels in preeclampsia: A systematic review

BACKGROUND

Preeclampsia represents a major pregnancy complication, associated with high rates of perinatal morbidity. The aim of this systematic review is to accumulate current literature evidence in order to examine the pattern of serum adipokine levels among preeclamptic women and asses their potential efficacy in the prediction of the disease.

METHODS

Medline, Scopus, CENTRAL, Clinicaltrials.gov and Google Scholar databases were systematically searched from inception. All observational studies reporting serum adipokine values among preeclamptic and healthy pregnant women were held eligible.

RESULTS

A total of 163 studies were included, comprising 23,482 women. Leptin was evaluated in 91 studies and its values were found to be significantly elevated in preeclamptic women during all pregnancy trimester, independently of disease onset and severity. Preeclampsia was also associated with increased serum fatty acid binding protein-4 and chemerin levels, when measured both during the 1st and 3rd trimester. Data concerning the rest adipokines were either conflicting or limited to reach firm conclusions. Quality of evidence was evaluated to be high for leptin, moderate for serum fatty acid binding protein-4 and chemerin and low for the other adipokines.

CONCLUSIONS

The existing evidence suggests that preeclampsia is linked to increased levels of leptin, chemerin and fatty acid binding protein-4 in all pregnancy trimesters and forms of the disease. Inconsistent data currently exists concerning the role of the other adipokines. Large-scale prospective studies should longitudinally evaluate the serum concentration of novel adipokines and define the optimal threshold and timing of measurement to be widely applied in clinical practice.

Irisin induces trophoblast differentiation via AMPK activation in the human placenta

Irisin, an adipokine, regulates differentiation and phenotype in various cell types including myocytes, adipocytes, and osteoblasts. Circulating irisin concentration increases throughout human pregnancy. In pregnancy disorders such as preeclampsia and gestational diabetes mellitus, circulating irisin levels are reduced compared to healthy controls. To date, there are no data on the role and molecular function of irisin in the human placenta or its contribution to pathophysiology. Aberrant trophoblast differentiation is involved in the pathophysiology of preeclampsia. The current study aimed to assess the molecular effects of irisin on trophoblast differentiation and function. First-trimester placental explants were cultured and treated with low (10 nM) and high (50 nM) physiological doses of irisin. Treatment with irisin dose-dependently increased both in vitro placental outgrowth (on Matrigel™) and trophoblast cell-cell fusion. Adenosine monophosphate-activated protein kinase (AMPK) signaling, an important regulator of cellular energy homeostasis that is involved in trophoblast differentiation and pathology, was subsequently investigated. Here, irisin exposure induced placental AMPK activation. To determine the effects of irisin on trophoblast differentiation, two trophoblast-like cell lines, HTR-8/SVneo and BeWo, were treated with irisin and/or a specific AMPK inhibitor (Compound C). Irisin-induced AMPK phosphorylation in HTR-8/SVneo cells. Additionally, as part of the differentiation process, integrin switching from α6 to α1 occurred as well as increased invasiveness. Overall, irisin promoted differentiation in villous and extravillous cell-based models via AMPK pathway activation. These findings provide evidence that exposure to irisin promotes differentiation and improves trophoblast functions in the human placenta that are affected in abnormal placentation.

Asprosin in umbilical cord of newborns and maternal blood of gestational diabetes, preeclampsia, severe preeclampsia, intrauterine growth retardation and macrosemic fetus

Pathological pregnancies, such as gestational diabetes, preeclampsia, severe preeclampsia, intrauterine growth retardation and macrosomic fetuses, are among the most fundamental problems of obstetrics clinics that are risk factors for both mother and child. Our main goal here is to compare maternal blood and newborn venous-arterial cord blood asprosin levels in pathological and healthy pregnancies. The study included 30 pregnant women with gestational diabetes, 30 with preeclampsia, 30 with severe preeclampsia, 30 with intrauterine growth retardation, 29 with macrosomic fetuses and 30 healthy pregnant women. All mothers were voluntary participants. Arteries and venous blood samples from both mothers and newborns were taken, in which asprosin levels were measured by ELISA. There was a statistically significant increase in asprosin levels in pregnant women with gestational diabetes, preeclampsia, severe preeclampsia and macrosemic fetuses compared with the control group, whereas in those with intrauterine growth retardation a significant decrease was observed. Venous and arterial cord blood asprosin levels were also close to maternal asprosin levels. Regarding the asprosin levels in venous and arterial cord blood in all newborns, the former was higher, but was not statistically significant.

Novel insights into the role of urotensin II in cardiovascular disease

Urotensin II (UII) is a vasoactive peptide that interacts with a specific receptor called the UT receptor. UII has been implicated in cardiovascular regulation, with promising therapeutic applications based on UT receptor antagonism. The endogenous ligands of the UT receptor: UII and urotensin-related peptide (URP), differentially bind and activate this receptor. Also, the receptor localization is not restricted to the plasma membrane, possibly inducing different physiological responses that could support its inconsistent, but potent, vasoactive activity. These properties could explain the disappointing outcomes in clinical studies, in contrast to the positive preclinical results regarding heart failure, pulmonary hypertension, atherosclerosis and diabetes mellitus. These aspects should be considered in future investigations to a better comprehension of the role of UII as a potential therapeutic target.

Urotensin 2 and Oxidative Stress Levels in Maternal Serum in Pregnancies Complicated by Intrauterine Growth Restriction

Background and objectives: In this study, the aim was to investigate Urotensin 2 (U-II) levels and oxidant/antioxidant system parameters in pregnancies with intrauterine growth restriction (IUGR). Materials and Methods: A total of 36 healthy, pregnant women who had not been diagnosed with IUGR and 36 pregnant women who had been diagnosed with IUGR at the Obstetrics and Gynecology Outpatient Clinic at Gaziantep University Hospital were enrolled in this study. The serum total antioxidant status (TAS), total oxidant status (TOS), thiol-disulfide levels, U-II measurements, and oxidative stress index (OSI) calculations were carried out at the biochemistry laboratory at Gaziantep University. Results: According to this study, there was no statistically significant difference between the group with IUGR and the control group of healthy, pregnant women in terms of total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), native thiol, total thiol, disulfide, disulfide/native thiol, disulfide/total thiol, native thiol/total thiol, and U-II values. There was, however, a positive linear correlation between TOS and total thiol levels in the group with IUGR (p = 0.021, r = 0.384), and a positive linear correlation between OSI and total thiol values in the control group (p = 0.049, r = 0.330). In addition, there was a negative correlation between disulfide levels and gestational weeks at birth in the group with IUGR (p = 0.027, r = 0.369). Conclusions: Consequently, there was no significant difference between the control group and the group with pregnancies complicated by idiopathic IUGR in terms of serum oxidant/antioxidant system parameters and U-II levels. It is necessary to conduct more extensive studies evaluating placental, maternal, and fetal oxidative stress in conjunction in order to investigate the role of oxidative stress in IUGR.

The Role of Myokines and Adipokines in Hypertension and Hypertension-related Complications

The cross-talk between skeletal muscle and adipose tissue has been identified to play a key role in the regulation of blood pressure and the development of hypertension. The role of different adipokines and myokines in hypertension and hypertension-related complications remains unclear. In the present study, 98 hypertensive patients and 24 normotensive controls were recruited, and additional subgroup analyses of hypertension-related complications were also performed. The levels of the circulating bone-derived factors leptin, apelin, fractalkine, brain-derived neurotrophic factor (BDNF), leukemia inhibitory factor (LIF), myostatin, fatty-acid-binding protein 3 (FABP3), irisin, follistatin-related protein 1 (FSTL1), oncostatin M, fibroblast growth factor 21 (FGF21) and musclin were measured by a protein liquid chip assay. The circulating levels of BDNF and musclin were decreased, whereas the leptin and irisin levels were increased, in hypertensive patients compared with those in the control individuals. Further logistic analysis indicated that the irisin level was positively correlated with SBP and an independent predictor for hypertension after adjustment. In nonobese subjects, the concentrations of DKK1, BDNF and FSTL1 were decreased, whereas the concentrations of leptin and irisin were increased. Irisin and DKK1 might be associated with hypertension. Additional subgroup analyses showed that irisin is significantly associated with hypertension-related stroke. In conclusion, we found that increased irisin levels are associated with hypertension and hypertension-related stroke. These findings indicate that irisin may be involved in the pathophysiology of hypertension.

Associations of Circulating Irisin Concentrations With Cardiometabolic Risk Factors Among Children Vary by Physical Activity or Sedentary Time Levels

Whether irisin concentrations are associated with physical activity (PA) and sedentary time (ST) remains unknown. The role of irisin on cardiometabolic health among children has been contradictory and scarce. This study aimed to examine associations of PA and ST with irisin concentrations and relationships between irisin concentrations and cardiometabolic parameters among children. Additionally, we assessed the interaction between PA or ST and irisin concentrations on cardiometabolic parameters. Basing on a cross-sectional survey of 3,651 general children aged 7-12 years, 575 with different self-reported PA (moderate-vigorous intensity PA ≥ 60 min/day or <150 min/week) and ST (gender-, age-specific ST ≥ 75% or <25% percentile) levels were selected. PA and ST were assessed by the validated international physical activity questionnaires. Fasting blood glucose and lipid profile levels were measured with standard methods by biochemistry analyzer. Plasma irisin concentrations were measured by ELISA. The associations of PA and ST with circulating irisin concentrations were examined by linear regression. Linear regression analysis was also used to estimate associations of circulating irisin concentrations with cardiometabolic variables. Interactions between PA or ST and irisin concentrations on cardiometabolic parameters were calculated using multiple linear regression models with dichotomized factors (low PA and high PA; low ST and high ST). No significant association was observed between circulating irisin concentrations and habitual PA or ST. Irisin concentrations were negatively associated with body mass index (BMI) (β = -0.220), BMI z-score (β = -0.098), waist circumference (β = -0.621), diastolic blood pressure (DBP) (β = -0.561), and triglyceride (β = -0.019) in low PA subgroup, and negatively related to fasting blood glucose (β = -0.040) among high PA subgroup. Moreover, irisin concentrations were negatively associated with BMI (β = -0.157) and fasting blood glucose (β = -0.026) only in high ST subgroup (all P < 0.05). We also observed a significant interaction between PA and irisin concentrations on BMI (P _interaction = 0.0350), BMI z-score (P _interaction = 0.0173), and DBP (P _interaction = 0.0068). In summary, irisin concentrations were not associated with habitual PA or ST in children. The negative associations of irisin concentrations with BMI, BMI z-score, and DBP were found only among children being inactive, implying that irisin may contribute to an improvement in health, especially among children with unhealthy lifestyles.

Irisin Maternal Plasma and Cord Blood Levels in Mothers with Spontaneous Preterm and Term Delivery

Irisin, an adipomyokine identified in 2012, has been investigated in association with common pregnancy complications, including gestational diabetes mellitus, preeclampsia, and intrauterine growth restriction. The objective of this study is to examine the potential role of irisin in preterm birth (PTB) by comparing its level between mothers with term and preterm labor. Maternal peripheral blood and cord blood samples were collected from 30 mothers who delivered prematurely and from 35 mothers who delivered at term. Irisin concentrations were measured in all samples using ELISA, and four common single nucleotide polymorphisms in the irisin gene were determined (rs16835198, rs726344, rs3480, and rs1746661). Univariable and multivariable regression modeling was applied to evaluate maternal and cord blood irisin concentrations in relation to preterm/term labor. Irisin concentration in umbilical cord blood was found to be associated with PTB in the univariable model (p = 0.046). On the other hand, no differences in maternal blood irisin levels between mothers with preterm and term deliveries were established. To the best of our knowledge, this is the first study determining irisin levels in term and preterm deliveries in maternal peripheral blood and umbilical cord blood. Our study shows a possible association between cord blood irisin concentration and PTB occurrence.