Role of leptin in the pathophysiology of preeclampsia

Exploring gene expression signatures in preeclampsia and identifying hub genes through bioinformatic analysis

INTRODUCTION

Preeclampsia (PE) is a multisystem disease that affects women during the pregnancy. Its pathogenicity remains unclear, and no definitive screening test can predict its occurrence so far. The aim of this study is to identify the critical genes that are involved in the pathogenicity of PE by applying integrated bioinformatic methods and to investigate the genes' diagnostic capability.

METHODS

Datasets that investigated PE have been downloaded from Gene Expression Omnibus (GEO) datasets. Differential gene expression, weighted gene co-expression analysis (WGCNA), protein-protein interaction (PPI) network construction, and finally, the calculation of area under the curve and Receiver operating characteristic curve (ROC) analysis were done for the potential hub genes. The results generated from the GSE186257 dataset (discovery cohort) were validated in the GSE75010 dataset (validation cohort). Following validation of the hub-genes, a multilayer regulatory network was constructed to include the up-stream regulatory elements (transcription factors and miRNAs) of the validated hub-genes.

RESULTS

WGCNA revealed six modules that were significantly correlated with PE. A total of 231 differentially expressed genes (DEGs) were identified. DEGs were intersected with the WGCNA modules' genes, totalling 55 genes. These shared genes were used to construct the PPI network; subsequently, four genes, namely FLT1, HTRA4, LEP and PAPPA2, were identified as hub-genes for PE in the discovery cohort. The expressional of these four hub genes were validated in the validation cohort and found to be highly expressed. ROC analysis in both datasets revealed that all these genes had a significant PE diagnostic ability. The regulatory network showed that FLT1 gene is the most connected and regulated gene among the validated hub-genes.

DISCUSSION

This integrated analysis revealed that FLT1, LEP, HTRA4 and PAPPA2 may be strongly involved in the pathogenicity of PE and act as promising biomarkers and potential therapeutic targets for PE.

Acquired Partial Lipodystrophy: Clinical Management in a Pregnant Patient

Background

Pregnancy represents an additional challenge to the complex clinical picture of lipodystrophy disorders, and the management of such conditions with related comorbidities has been underreported. This work aims to outline the risk associated with a pregnancy event for women dealing with acquired partial lipodystrophy and the need for diverse but specialized care.

Case

We report on the successful pregnancy outcome of a 28-year-old woman with an acquired partial form of lipodystrophy related to an allogenic bone marrow transplant that occurred at pediatric age. Although metabolic control was challenging, glucose levels progressively improved during the pregnancy, and triglycerides increased less than expected. The periodic monitoring of leptin levels showed a progressive increase with a peak in the third trimester (41.53 ng/mL), followed by a fast decline the day after giving birth, with a lower basal level than the prepregnancy period. However, preterm delivery occurred associated with cardiac complications in the mother.

Results

A total of 12 studies were retrieved concerning women aged 14 to 38 years with various lipodystrophy phenotypes. Diabetes and hypertriglyceridemia were the most common comorbidities. Most women had successful pregnancies despite gestational complications (including miscarriages), preterm and emergency deliveries, and newborns undergoing partum or postpartum transient or chronic complications.

Conclusion

Lipodystrophy disorders expose both mothers and children to very high risk. Intensive monitoring and care of all potential clinical complications should be planned and carried out by a multidisciplinary team before, during, and after the pregnancy. Leptin secretion during pregnancy should be investigated more deeply in these patients.

Preeclampsia: A comprehensive review

Preeclampsia (PE) is a life-threatening disease of pregnancy and a prominent cause of neonatal and maternal mortality and morbidity. PE affects approximately 5-10% of pregnancies worldwide, posing significant risks to perinatal and maternal health. It is characterized by a variety of interconnected pathological cascades contributing to the stimulation of intravascular inflammation, oxidative stress (OS), endothelial cell activation, and syncytiotrophoblast stress that converge on a common pathway, ultimately resulting in disease progression. The present study was designed and executed to review the existing scientific literature, specifically focusing on the etiology (gestational diabetes mellitus and maternal obesity, insulin resistance, metabolic syndrome, maternal infection, periodontal disease, altered microbiome, and genetics), clinical presentations (hypertension, blood disorders, proteinuria, hepatic dysfunction, renal dysfunction, pulmonary edema, cardiac dysfunction, fetal growth restrictions, and eclampsia), therapeutic clinical biomarkers (creatinine, albuminuria, and cystatin C) along with their associations and mechanisms in PE. In addition, this study provides insights into the potential of nanomedicines for targeting these mechanisms for PE management and treatment. Inflammation, OS, proteinuria, and an altered microbiome are prominent biomarkers associated with progression and PE-related pathogenesis. Understanding the molecular mechanisms, exploring suitable markers, targeted interventions, comprehensive screening, and holistic strategies are critical to decreasing the incidence of PE and promoting maternal-fetal well-being. The present study comprehensively reviewed the etiology, clinical presentations, therapeutic biomarkers, and preventive potential of nanomedicines in the treatment and management of PE.

The Roles of Obesity and ASB4 in Preeclampsia Pathogenesis

Preeclampsia is a complex pregnancy-related hypertensive disorder which poses significant risks for both maternal and fetal health. Preeclampsia affects 5-8% of pregnancies in the United States, causing a significant public health and economic burden. Despite extensive research, the etiology and pathogenesis of preeclampsia remain elusive, but have been correlated with maternal conditions such as obesity. In recent decades, the incidence of preeclampsia increased along with the prevalence of obesity among women of reproductive age. Maternal obesity has been shown to negatively affect pregnancy in almost all aspects. However, the precise mechanisms by which obesity influences preeclampsia are unclear. Ankyrin repeat and SOCS Box Containing protein 4 (ASB4) is an E3 ubiquitin ligase that can promote the degradation of a wide range of target proteins. ASB4-null mice display a full spectrum of preeclampsia-like phenotypes during pregnancy including hypertension, proteinuria, and decreased litter size. Furthermore, maternal obesity induced by a high-fat diet aggravates preeclampsia-like phenotypes in pregnant mice lacking ASB4. Variants in the ASB4 gene have been associated with obesity in humans, and a functional connection between the ASB4 gene and obesity has been established in mice. This review discusses the connections between preeclampsia, obesity, and ASB4.

A Narrative Review on the Pathophysiology of Preeclampsia

Preeclampsia (PE) is a multifactorial pregnancy disorder characterized by hypertension and proteinuria, posing significant risks to both maternal and fetal health. Despite extensive research, its complex pathophysiology remains incompletely understood. This narrative review aims to elucidate the intricate mechanisms contributing to PE, focusing on abnormal placentation, maternal systemic response, oxidative stress, inflammation, and genetic and epigenetic factors. This review synthesizes findings from recent studies, clinical trials, and meta-analyses, highlighting key molecular and cellular pathways involved in PE. The review integrates data on oxidative stress biomarkers, angiogenic factors, immune interactions, and mitochondrial dysfunction. PE is initiated by poor placentation due to inadequate trophoblast invasion and improper spiral artery remodeling, leading to placental hypoxia. This triggers the release of anti-angiogenic factors such as soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sEng), causing widespread endothelial dysfunction and systemic inflammation. Oxidative stress, mitochondrial abnormalities, and immune dysregulation further exacerbate the condition. Genetic and epigenetic modifications, including polymorphisms in the Fms-like tyrosine kinase 1 (FLT1) gene and altered microRNA (miRNA) expression, play critical roles. Emerging therapeutic strategies targeting oxidative stress, inflammation, angiogenesis, and specific molecular pathways like the heme oxygenase-1/carbon monoxide (HO-1/CO) and cystathionine gamma-lyase/hydrogen sulfide (CSE/H2S) pathways show promise in mitigating preeclampsia's effects. PE is a complex disorder with multifactorial origins involving abnormal placentation, endothelial dysfunction, systemic inflammation, and oxidative stress. Despite advances in understanding its pathophysiology, effective prevention and treatment strategies remain limited. Continued research is essential to develop targeted therapies that can improve outcomes for both mothers and their babies.

Leptin in reproduction and hypertension in pregnancy

Leptin has important roles in numerous physiological functions, including those in the regulation of energy balance, and in immune and reproductive systems. However, in the recent years, evidence has implicated it in a number of obesity-related diseases, where its concentrations in serum are significantly elevated. Elevated serum leptin concentrations and increased placental leptin secretion have been reported in women with hypertensive disorders of pregnancy. Whether leptin is responsible for this disorder remains to be established. Leptin injections in healthy rats and mice during pregnancy result in endothelial activation, increased blood pressure and proteinuria. A potential role for leptin in the pathogenesis of pre-eclampsia is hypothesised, particularly in women who are overweight or obese where serum leptin concentrations are often elevated. This review summarises pertinent information in the literature on the role of leptin in puberty, pregnancy, and hypertensive disorders of pregnancy. In particular, the possible mechanism that may be involved in leptin-induced increase in blood pressure and proteinuria during pregnancy and the potential role of marinobufagenin in this disease entity. We hypothesise a significant role for oxidative stress in this, and propose a conceptual framework on the events that lead to endothelial activation, raised blood pressure and proteinuria following leptin administration.

A cross-sectional analysis of syncytiotrophoblast membrane extracellular vesicles-derived transcriptomic biomarkers in early-onset preeclampsia

Background

Preeclampsia (PE) is a pregnancy-specific hypertensive disorder affecting 2%-8% of pregnancies worldwide. Biomarker(s) for the disorder exists, but while these have excellent negative predictive value, their positive predictive value is poor. Extracellular vesicles released by the placenta into the maternal circulation, syncytiotrophoblast membrane extracellular vesicles (STB-EVs), have been identified as being involved in PE with the potential to act as liquid biopsies.

Objective

The objective of this study was to identify the difference in the transcriptome of placenta and STB-EVs between preeclampsia and normal pregnancy (NP) and mechanistic pathways.

Methods/study design

We performed RNA-sequencing on placental tissue, medium/large and small STB-EVs from PE (n = 6) and NP (n = 6), followed by bioinformatic analysis to identify targets that could be used in the future for EV-based diagnostic tests for preeclampsia. Some of the identified biomarkers were validated with real-time polymerase chain reactions.

Results

Our analysis identified a difference in the transcriptomic STB-EV cargo between PE and NP. We then identified and verified the differential expression of FLNB, COL17A1, SLC45A4, LEP, HTRA4, PAPP-A2, EBI3, HSD17B1, FSTL3, INHBA, SIGLEC6, and CGB3. Our analysis also identified interesting mechanistic processes via an in silico prediction of STB-EV-based mechanistic pathways.

Conclusions

In this study, using comprehensive profiling of differentially expressed/carried genes of three linked sample subtypes in PE, we identified potential biomarkers and mechanistic gene pathways that may be important in the pathophysiology of PE and could be further explored in future studies.