Increased placental expressions of nuclear factor erythroid 2-related factor 2 and antioxidant enzymes in gestational diabetes: Protective mechanisms against the placental oxidative stress?

Metformin ameliorates gestational diabetes mellitus via inhibiting ferroptosis of trophoblasts through the Nrf2/HO-1 signaling pathway

Both mothers and infants experience oxidative stress due to gestational diabetes mellitus (GDM), which is strongly associated with adverse pregnancy outcomes. Ferroptosis, a novel form of programmed cell death characterized by iron-dependent lipid peroxidation, is believed to play a critical role in the pathogenesis and progression of GDM. Metformin (MET) has shown potential in alleviating oxidative stress; however, research on its specific mechanisms of action in GDM remains limited. We collected placental tissues from GDM patients and healthy controls and established an in vitro GDM cell model. We measured markers of ferroptosis including malondialdehyde (MDA), glutathione (GSH), and glutathione peroxidase 4 (GPX4) activity. Additionally, we evaluated reactive oxygen species (ROS) levels, apoptosis, cell viability, and migration in the cell model. Our findings revealed significant changes in the GDM group compared to controls, including increased MDA and GSSG levels, decreased GSH levels, and reduced expression of GPX4 protein in the GDM placenta. High-glucose (HG) conditions were shown to reduce trophoblast cell viability and migration, accompanied by elevated ROS and MDA levels, as well as reduced expression of GSH, GPX4, Nrf2, and HO-1 proteins. Importantly, treatment with MET reversed these effects, similar to the action of deferoxamine mesylate (DFOM), a known ferroptosis inhibitor. These results confirm the occurrence of ferroptosis in the placentas of GDM patients and demonstrate that MET mitigates high-glucose-induced ferroptosis in trophoblasts through the Nrf2/HO-1 signaling pathway. This study provides novel insights into the protective mechanisms of MET, offering potential therapeutic strategies for GDM. management.

Assessment for Diabetic Neuropathy: Treatment and Neurobiological Perspective

Diabetic neuropathy, also known as diabetic peripheral sensorimotor neuropathy (DPN), is a consequential complexity of diabetes, alongside diabetic nephropathy, diabetic cardiomyopathy, and diabetic retinopathy. It is characterized by signs and symptoms of peripheral nerve damage in diabetes patients after ruling out other causes. Approximately 20% of people with diabetes are affected by this painful and severe condition. The development of diabetic neuropathy is influenced by factors such as impaired blood flow to the peripheral nerves and metabolic issues, including increased polyol pathway activation, myo-inositol loss, and nonenzymatic glycation. The present review article provides a brief overview of the pathological changes in diabetic neuropathy and the mechanisms and types of DPN. Various diagnostic tests and biomarkers are available to assess nerve damage and its severity. Pharmacotherapy for neuropathic pain in diabetic neuropathy is complex. This review will explore current treatment options and potential future developments to improve the quality of life for patients suffering from diabetic neuropathy.

Analysis of the evolution of placental oxidative stress research from a bibliometric perspective

Background

Research on placental oxidative stress is pivotal for comprehending pregnancy-related physiological changes and disease mechanisms. Despite recent advancements, a comprehensive review of current status, hotspots, and trends remains challenging. This bibliometric study systematically analyzes the evolution of placental oxidative stress research, offering a reference for future studies.

Objective

To conduct a comprehensive bibliometric analysis of the literature on placental oxidative stress to identify research hotspots, trends, and key contributors, thereby providing guidance for future research.

Methods

Relevant data were retrieved from the Web of Science Core Collection database and analyzed using VOSviewer, CiteSpace, and the bibliometrix package. An in-depth analysis of 4,796 publications was conducted, focusing on publication year, country/region, institution, author, journal, references, and keywords. Data collection concluded on 29 April 2024.

Results

A total of 4,796 papers were retrieved from 1,173 journals, authored by 18,835 researchers from 4,257 institutions across 103 countries/regions. From 1991 to 2023, annual publications on placental oxidative stress increased from 7 to 359. The United States (1,222 publications, 64,158 citations), the University of Cambridge (125 publications, 13,562 citations), and Graham J. Burton (73 publications, 11,182 citations) were the most productive country, institution, and author, respectively. The journal Placenta had the highest number of publications (329) and citations (17,152), followed by the International Journal of Molecular Sciences (122 publications). The most frequent keywords were "oxidative stress," "expression," "pregnancy," "preeclampsia," and "lipid peroxidation." Emerging high-frequency keywords included "gestational diabetes mellitus," "health," "autophagy," "pathophysiology," "infection," "preterm birth," "stem cell," and "inflammation."

Conclusion

Over the past 3 decades, research has concentrated on oxidative stress processes, antioxidant mechanisms, pregnancy-related diseases, and gene expression regulation. Current research frontiers involve exploring pathophysiology and mechanisms, assessing emerging risk factors and environmental impacts, advancing cell biology and stem cell research, and understanding the complex interactions of inflammation and immune regulation. These studies elucidate the mechanisms of placental oxidative stress, offering essential scientific evidence for future intervention strategies, therapeutic approaches, and public health policies.

Antioxidant Defense Expressed as Glutathione Status and Keap1-Nrf2 System Action in Relation to Anthropometric Parameters and Body Composition in Young Women with Polycystic Ovary Syndrome

Metabolic disorders present in women with polycystic ovary syndrome (PCOS) and the associated risk of obesity may result in increased oxidative stress and reproductive failure. Therefore, we evaluated the concentrations of reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione peroxidase (GPx), and reductase (GR), as well as nuclear factor erythroid 2-related factor 2 (Nrf2) and Kelch-like ECH-associating protein1 (Keap1) in the serum of 56 women with PCOS divided according to the visceral to subcutaneous fat surface ratio (VAT/SAT) and waist-to-hip ratio (WHR) values. Antioxidant parameter levels were measured by competitive inhibition enzyme immunoassay technique. As the VAT/SAT ratio and WHR increased, we observed significantly higher concentrations of GSSG and Keap1 protein and a lower value of the GSSG/GSH ratio (R-index), which is considered an index of cellular redox (p < 0.05). Negative correlations were found between the R-index and body weight, BMI, WHR, subcutaneous and visceral fat surface and the VAT/SAT ratio, and total body fat; positive links were found with fat free mass and total body water. Opposite associations were noted between GSSG level and the aforementioned body composition parameters. Oxidative stress characterized by a depleted reduced-to-oxidized glutathione index is associated with anthropometric and body composition parameters in women with PCOS. In particular, abdominal obesity expressed by the VAT/SAT ratio and/or WHR seems to have a negative impact on glutathione status, which may lead to a disruption of many biological cell processes. The observed negative association of Keap1 with R-index suggests that the elevated oxidative changes dependent on the VAT/SAT ratio may lead to Nrf2 activation to promote antioxidant enzyme expression. Although the GSH/GSSG index as well as the VAT/SAT ratio appear to be good indicators of oxidative status, studies on a larger group of patients should continue to confirm these links among women with PCOS.

New Advances on Pathophysiology of Diabetes Neuropathy and Pain Management: Potential Role of Melatonin and DPP-4 Inhibitors

Pre-diabetes and diabetes are growing threats to the modern world. Diabetes mellitus (DM) is associated with comorbidities such as hypertension (83.40%), obesity (90.49%), and dyslipidemia (93.43%), creating a substantial burden on patients and society. Reductive and oxidative (Redox) stress level imbalance and inflammation play an important role in DM progression. Various therapeutics have been investigated to treat these neuronal complications. Melatonin and dipeptidyl peptidase IV inhibitors (DPP-4i) are known to possess powerful antioxidant and anti-inflammatory properties and have garnered significant attention in the recent years. In this present review article, we have reviewed the recently published reports on the therapeutic efficiency of melatonin and DPP-4i in the treatment of DM. We summarized the efficacy of melatonin and DPP-4i in DM and associated complications of diabetic neuropathy (DNP) and neuropathic pain. Furthermore, we discussed the mechanisms of action and their efficacy in the alleviation of oxidative stress in DM.

The role of nuclear factor erythroid 2-related factor 2 (NRF2) in normal and pathological pregnancy: A systematic review

OBJECTIVE

A homeostatic balance between reactive oxygen species production and the antioxidant redox system is an important component of normal pregnancy. Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) preserves cellular homeostasis by enhancing the cell's innate antioxidant status to reduce oxidative stress and inflammatory damage to the cell during pregnancy. Active Nrf2, in the nucleus of the cell, transactivates various antioxidant genes. The objective of this systematic review was to synthesize evidence on the role of Nrf2 in various adverse pregnancy outcomes (APOs).

METHODS

We conducted a systematic review of the role of Nrf2 in pregnancy. Articles written in English, Portuguese, and Spanish were obtained from three different databases from inception until January 2021. The titles, abstracts and full text were reviewed independently by six reviewers. The quality of the included studies was assessed using a quality assessment tool developed to assess basic science and clinical studies. Nrf2 expression (gene and protein), functional contributions, and association with APOs were assessed.

RESULTS

A total of 747 citations were identified; 80 were retained for full review. Most studies on Nrf2 have been carried out using placental tissues and placenta-derived cells. Limited studies have been conducted using fetal membranes, uterus, and cervix. Nuclear translocation of Nrf2 results in transactivation of antioxidant enzymes, including glutathione peroxidase, hemeoxygenase-1, and superoxide dismutase in gestational cells during pregnancy. This antioxidant response maintains cellular homeostasis during pregnancy. This promotes trophoblast cell survival and prevents cell death and abnormal angiogenesis in the placenta. Excessive and insufficient Nrf2 response may promote oxidative and reductive stress, respectively. This Nrf2 dysregulation has been associated with APOs including gestational diabetes mellitus, intrauterine growth restriction, reproductive toxicity, preeclampsia, and preterm birth.

CONCLUSION

Several studies have localized and reported an association between Nrf2's differential expression in reproductive tissues and the pathogenesis of APOs. However, a comprehensive functional understanding of Nrf2 in reproductive tissues is still lacking. Nrf2's activation and functions are complex, and therefore, current in vitro and in vivo studies are limited in their experimental approaches. We have identified key areas for future Nrf2 research that is needed to fill knowledge gaps.

Comparison of elasticity values in normal and gestational diabetic pregnancies in the third trimester

Placental elasticity was compared by using Shear wave elastography (SWE) in patients with gestational diabetes mellitus (GDM) with and without insulin to non-diabetic controls. Three groups were created as follows: Group 1 (n = 79, GDM with insulin therapy), Group 2 (n = 90, GDM with only diet) and Group 3 (n = 150, healthy controls) All patients were above 36 gestational weeks with anterior placenta. Clinical trial number was also received (NCT04455880). Group 1 had higher BMI while group 3 had lowest rate of C/S. Birthweight in GDM groups was statistically significantly higher than controls (p = .001). Although there was no significant difference between APGAR scores, Group 1 had higher rates of neonatal intensive care unit (NICU) admission. SWE values were significantly higher in GDM patients treated with insulin or diet than controls. SWE may be an alternatively supplementary management modality in GDM.IMPACT STATEMENTWhat is already known on this subject? Shear wave elastography (SWE), is one of the types of sono elastography methods that are used to measure the stiffness and elasticity of soft tissues. Recently, it became popular for screening the stiffness and elasticity of the placenta in high-risk pregnancies like preeclampsia, intrauterine growth restriction (IUGR), and placental dysfunction.What the results of this study add? All SWE velocities on the maternal side were statistically significantly different between groups. Regarding foetal side velocities, GDM groups had statistically significantly higher values (stiffer tissue) compared to controls.What the implications are of these findings for clinical practice and/or further research? SWE may be a Supplementary method in the diagnosis and management of GDM. Placental SWE should be measured at 24-28 weeks of gestation in patients with GDM and diagnosis confirmation and their responses to the treatment should be examined.

Immunoendocrine Dysregulation during Gestational Diabetes Mellitus: The Central Role of the Placenta

Gestational Diabetes Mellitus (GDM) is a transitory metabolic condition caused by dysregulation triggered by intolerance to carbohydrates, dysfunction of beta-pancreatic and endothelial cells, and insulin resistance during pregnancy. However, this disease includes not only changes related to metabolic distress but also placental immunoendocrine adaptations, resulting in harmful effects to the mother and fetus. In this review, we focus on the placenta as an immuno-endocrine organ that can recognize and respond to the hyperglycemic environment. It synthesizes diverse chemicals that play a role in inflammation, innate defense, endocrine response, oxidative stress, and angiogenesis, all associated with different perinatal outcomes.

Decreased maternal serum adiponectin and increased insulin-like growth factor-1 levels along with increased placental glucose transporter-1 expression in gestational diabetes mellitus: Possible role in fetal overgrowth

INTRODUCTION

The placental glucose transporter - 1 (GLUT-1) is involved in the transplacental glucose transport to the fetus. GLUT-1 expressions are increased in diabetic pregnancies and associated with altered fetal growth. However, the factors regulating the GLUT-1 expressions are largely unknown. We hypothesised that maternal adipokines and insulin-like growth factor-1 (IGF1) modulate the placental expressions of GLUT-1 through the activation of insulin/IGF-1 signalling which may contribute to a fetal overgrowth in GDM.

METHODS

Maternal blood, cord blood and placental samples were collected from GDM and control pregnant women (CPW). The biochemical parameters, IGF1, adipokines, and high sensitive C- reactive protein were measured. We analysed the placental expressions of GLUT-1 and proteins related to insulin/IGF-1 signalling - insulin receptor -β, insulin receptor substrate - 1, phosphatidylinositol-3-kinase p110α, phospho Akt-1, phospho extracellular signal-regulated kinase 1/2, and nuclear factor-κB p65 in GDM and CPW.

RESULTS

Increased maternal IGF-1 and decreased adiponectin levels were found in the GDM women. Maternal IGF-1 levels were positively correlated, whereas adiponectin levels were negatively correlated with the birth weight of GDM newborns. Increased phosphorylation of Akt and ERK 1/2 was found in the placenta of GDM women. Placental expressions of GLUT-1 were significantly higher in the GDM women and positively correlated to the maternal IGF-1 levels in the GDM group.

DISCUSSION

Decreased maternal adiponectin and increased IGF-1 levels might have caused increased GLUT-1 expression via the increased activation of insulin/IGF-1 signalling in the placenta of GDM women which might have influenced the fetal growth.

Metformin Ameliorates Gestational Diabetes Mellitus-Induced Endothelial Dysfunction via Downregulation of p65 and Upregulation of Nrf2

Gestational diabetes mellitus (GDM) causes oxidative stress in mothers and infants and causes vascular endothelial dysfunction, which is a key factor for maternal and fetal cardiovascular diseases in the later stage of GDM, seriously threatening the life and health of mothers and infants. Nowadays, metformin (MET) has been discovered to improve endothelial function, but studies regarding the mechanism of MET improving endothelial cell function and alleviating endothelial function under hyperglycemia are still extremely limited. We aimed to investigate whether MET exerts its protective role against hyperglycemia-induced endothelial dysfunction through p65 and Nrf2. In our studies, applying cell migration assay and tube formation assay, we observed an obvious improvement of endothelial function under MET-treated, as characterized by that MET accelerated GDM-attenuated migration and angiogenesis of HUVECs. And ELISA assay results uncovered that Nrf2 expression level was decreased in GDM placenta, HVUECs and maternal serum comparing with normal group, however activation Nrf2 largely ameliorated tube formation under hyperglycemic condition. Furthermore, MET elevated the Nrf2 expression level and the level of nuclear Nrf2 accumulation in hyperglycemic HUVECs. Besides, preliminary evidence predicted that Nrf2 expression was modulated by transcription factor p65, which was increased in GDM peripheral blood, placenta and HUVECs, and suppression of p65 could recover GDM-induced suppression of angiogenesis. In addition, we also confirmed MET restores the GDM-induced angiogenesis impairment may via downregulation of p65 and upregulation of Nrf2. Taken together, the endothelial protective effect of MET under GDM (HG) conditions could be partly attributed to its role in downregulating p65 and upregulating Nrf2.

Placental Accumulation of Triacylglycerols in Gestational Diabetes Mellitus and Its Association with Altered Fetal Growth are Related to the Differential Expressions of Proteins of Lipid Metabolism

INTRODUCTION

Gestational diabetes mellitus (GDM) exhibit altered placental lipid metabolism. The molecular basis of this altered metabolism is not clear. Altered placental expression of proteins of lipogenesis and fatty acid oxidation may be involved in the placental accumulation of triacylglycerols (TG). The present study was aimed at investigating the differential expressions of placental proteins related to lipid metabolism among GDM women in comparison with control pregnant women (CPW) and to correlate them with maternal and fetal lipid parameters as well as altered fetal growth.

MATERIALS AND METHODS

Maternal blood, cord blood, and placental samples were collected from GDM and CPW. The biochemical parameters, glucose, lipid profile and free fatty acids (FFA) were measured. The placental TG content was measured. Differential placental expressions of proteins; phosphatidylinositol-3-kinase (PI3K) p85α, PI3K p110α,liver X receptor alpha (LXRα), sterol regulatory element binding protein1(SREBP1), fatty acid synthase (FAS), stearyl CoA desaturase1 (SCD1), lipoprotein lipase (LPL),Peroxisome proliferator-activated receptor (PPAR)α and PPARγ were analysed by western blotting and immunohistochemistry.

RESULTS

Placental protein expressions of PI3K p110α, LXRα, FAS, SCD1, and LPL were found to be significantly higher, whereas PPARα and PPARγ were lower in GDM women compared with CPW. The placental TG content and cord plasma FFA were increased in GDM women compared with CPW. The placental TG content positively correlated with Ponderal index of GDM new-borns.

CONCLUSION

Differential expressions of placental proteins related to lipid metabolism in GDM might have led to placental TG accumulation. This might have contributed to the fetal overgrowth in GDM.

Specialized pro-resolving mediators in diabetes: novel therapeutic strategies

Diabetes mellitus (DM) is an important metabolic disorder characterized by persistent hyperglycemia resulting from inadequate production and secretion of insulin, impaired insulin action, or a combination of both. Genetic disorders and insulin receptor disorders, environmental factors, lifestyle choices and toxins are key factors that contribute to DM. While it is often referred to as a metabolic disorder, modern lifestyle choices and nutrient excess induce a state of systemic chronic inflammation that results in the increased production and secretion of inflammatory cytokines that contribute to DM. It is chronic hyperglycemia and the low-grade chronic-inflammation that underlies the development of microvascular and macrovascular complications leading to damage in a number of tissues and organs, including eyes, vasculature, heart, nerves, and kidneys. Improvements in the management of risk factors have been beneficial, including focus on intensified glycemic control, but most current approaches only slow disease progression. Even with recent studies employing SGLT2 inhibitors demonstrating protection against cardiovascular and kidney diseases, kidney function continues to decline in people with established diabetic kidney disease (DKD). Despite the many advances and a greatly improved understanding of the pathobiology of diabetes and its complications, there remains a major unmet need for more effective therapeutics to prevent and reverse the chronic complications of diabetes. More recently, there has been growing interest in the use of specialised pro-resolving mediators (SPMs) as an exciting therapeutic strategy to target diabetes and the chronic complications of diabetes.