Pregnancy-associated plasma protein-A (PAPP-A): a local regulator of IGF bioavailability through cleavage of IGFBPs

Polygenic Risk Score-Based Association Analysis Identifies Genetic Comorbidities Associated with Age-Related Hearing Difficulty in Two Independent Samples

PURPOSE

Age-related hearing loss is the most common form of permanent hearing loss that is associated with various health traits, including Alzheimer's disease, cognitive decline, and depression. The present study aims to identify genetic comorbidities of age-related hearing loss. Past genome-wide association studies identified multiple genomic loci involved in common adult-onset health traits. Polygenic risk scores (PRS) could summarize the polygenic inheritance and quantify the genetic susceptibility of complex traits independent of trait expression. The present study conducted a PRS-based association analysis of age-related hearing difficulty in the UK Biobank sample (N = 425,240), followed by a replication analysis using hearing thresholds (HTs) and distortion-product otoacoustic emissions (DPOAEs) in 242 young adults with self-reported normal hearing. We hypothesized that young adults with genetic comorbidities associated with age-related hearing difficulty would exhibit subclinical decline in HTs and DPOAEs in both ears.

METHODS

A total of 111,243 participants reported age-related hearing difficulty in the UK Biobank sample (> 40 years). The PRS models were derived from the polygenic risk score catalog to obtain 2627 PRS predictors across the health spectrum. HTs (0.25-16 kHz) and DPOAEs (1-16 kHz, L1/L2 = 65/55 dB SPL, F2/F1 = 1.22) were measured on 242 young adults. Saliva-derived DNA samples were subjected to low-pass whole genome sequencing, followed by genome-wide imputation and PRS calculation. The logistic regression analyses were performed to identify PRS predictors of age-related hearing difficulty in the UK Biobank cohort. The linear mixed model analyses were performed to identify PRS predictors of HTs and DPOAEs.

RESULTS

The PRS-based association analysis identified 977 PRS predictors across the health spectrum associated with age-related hearing difficulty. Hearing difficulty and hearing aid use PRS predictors revealed the strongest association with the age-related hearing difficulty phenotype. Youth with a higher genetic predisposition to hearing difficulty revealed a subclinical elevation in HTs and a decline in DPOAEs in both ears. PRS predictors associated with age-related hearing difficulty were enriched for mental health, lifestyle, metabolic, sleep, reproductive, digestive, respiratory, hematopoietic, and immune traits. Fifty PRS predictors belonging to various trait categories were replicated for HTs and DPOAEs in both ears.

CONCLUSION

The study identified genetic comorbidities associated with age-related hearing loss across the health spectrum. Youth with a high genetic predisposition to age-related hearing difficulty and other related complex traits could exhibit sub-clinical decline in HTs and DPOAEs decades before clinically meaningful age-related hearing loss is observed. We posit that effective communication of genetic risk, promoting a healthy lifestyle, and reducing exposure to environmental risk factors at younger ages could help prevent or delay the onset of age-related hearing difficulty at older ages.

Racial and Ethnic Disparities in Stillbirth among Pregnant Women with Obesity

OBJECTIVE

The aim of this study was to examine the relationship between obesity and risk of stillbirth among pregnant women with obesity in the United States, with a focus on racial and ethnic disparities.

STUDY DESIGN

We conducted a retrospective cross-sectional analysis of birth and fetal data from the 2014 to 2019 National Vital Statistics System (N = 14,938,384 total births) to examine associations between maternal body mass index (BMI) and risk of stillbirth. Cox's proportional hazards regression model was used to compute adjusted hazard ratios (HR) as a measure of risk of stillbirth in relation to maternal BMI.

RESULTS

The stillbirth rate was 6.70 per 1,000 births among women with prepregnancy obesity, while the stillbirth rate among women with a normal (nonobese) prepregnancy BMI was 3.85 per 1,000 births. The risk of stillbirth was greater among women with obesity compared with women without obesity (HR: 1.39; 95% confidence interval [CI]: 1.37-1.41). Compared with non-Hispanic (NH) Whites, women identifying as NH-other (HR: 1.66; 95% CI: 1.61-1.72) and NH-Black (HR: 1.31; 95% CI: 1.26-1.35) were at higher risk of stillbirth, while Hispanic women had a decreased likelihood of stillbirth (HR: 0.38; 95% CI: 0.37-0.40).

CONCLUSION

Obesity is a modifiable risk factor for stillbirth. Public health awareness campaigns and strategies targeting weight management in women of reproductive age and racial/ethnic populations at highest risk for stillbirth, are needed.

KEY POINTS

· Stillbirth rates differ by race and ethnicity.. · Risk of stillbirth was greatest among women with obesity.. · Stillbirth rates rise with ascending prepregnancy BMI..

Bridging the divide: unveiling mutual immunological pathways of cancer and pregnancy

The juxtaposition of two seemingly disparate physiological phenomena within the human body-namely, cancer and pregnancy-may offer profound insights into the intricate interplay between malignancies and the immune system. Recent investigations have unveiled striking similarities between the pivotal processes underpinning fetal implantation and successful gestation and those governing tumor initiation and progression. Notably, a confluence of features has emerged, underscoring parallels between the microenvironment of tumors and the maternal-fetal interface. These shared attributes encompass establishing vascular networks, cellular mobilization, recruitment of auxiliary tissue components to facilitate continued growth, and, most significantly, the orchestration of immune-suppressive mechanisms.Our particular focus herein centers on the phenomenon of immune suppression and its protective utility in both of these contexts. In the context of pregnancy, immune suppression assumes a paramount role in shielding the semi-allogeneic fetus from the potentially hostile immune responses of the maternal host. In stark contrast, in the milieu of cancer, this very same immunological suppression fosters the transformation of the tumor microenvironment into a sanctuary personalized for the neoplastic cells.Thus, the striking parallels between the immunosuppressive strategies deployed during pregnancy and those co-opted by malignancies offer a tantalizing reservoir of insights. These insights promise to inform novel avenues in the realm of cancer immunotherapy. By harnessing our understanding of the immunological events that detrimentally impact fetal development, a knowledge grounded in the context of conditions such as preeclampsia or miscarriage, we may uncover innovative immunotherapeutic strategies to combat cancer.

The sirtuin-associated human senescence program converges on the activation of placenta-specific gene PAPPA

Sirtuins are pro-longevity genes with chromatin modulation potential, but how these properties are connected is not well understood. Here, we generated a panel of isogeneic human stem cell lines with SIRT1-SIRT7 knockouts and found that any sirtuin deficiency leads to accelerated cellular senescence. Through large-scale epigenomic analyses, we show how sirtuin deficiency alters genome organization and that genomic regions sensitive to sirtuin deficiency are preferentially enriched in active enhancers, thereby promoting interactions within topologically associated domains and the formation of de novo enhancer-promoter loops. In all sirtuin-deficient human stem cell lines, we found that chromatin contacts are rewired to promote aberrant activation of the placenta-specific gene PAPPA, which controls the pro-senescence effects associated with sirtuin deficiency and serves as a potential aging biomarker. Based on our survey of the 3D chromatin architecture, we established connections between sirtuins and potential target genes, thereby informing the development of strategies for aging interventions.

The role of pregnancy associated plasma protein-A in triple negative breast cancer: a promising target for achieving clinical benefits

Pregnancy associated plasma protein-A (PAPP-A) plays an integral role in breast cancer (BC), especially triple negative breast cancer (TNBC). This subtype accounts for the most aggressive BC, possesses high tumor heterogeneity, is least responsive to standard treatments and has the poorest clinical outcomes. There is a critical need to address the lack of effective targeted therapeutic options available. PAPP-A is a protein that is highly elevated during pregnancy. Frequently, higher PAPP-A expression is detected in tumors than in healthy tissues. The increase in expression coincides with increased rates of aggressive cancers. In BC, PAPP-A has been demonstrated to play a role in tumor initiation, progression, metastasis including epithelial-mesenchymal transition (EMT), as well as acting as a biomarker for predicting patient outcomes. In this review, we present the role of PAPP-A, with specific focus on TNBC. The structure and function of PAPP-A, belonging to the pappalysin subfamily, and its proteolytic activity are assessed. We highlight the link of BC and PAPP-A with respect to the IGFBP/IGF axis, EMT, the window of susceptibility and the impact of pregnancy. Importantly, the relevance of PAPP-A as a TNBC clinical marker is reviewed and its influence on immune-related pathways are explored. The relationship and mechanisms involving PAPP-A reveal the potential for more treatment options that can lead to successful immunotherapeutic targets and the ability to assist with better predicting clinical outcomes in TNBC.

Correlation Between PAPP-A Levels Determined During the First Trimester and Birth Weight at Full-Term

Foetal birth weight is an important determinant of perinatal health. For this reason, various methods have been investigated for estimating this weight during pregnancy. The aim of this study is to evaluate the possible relationship between full-term birth weight and pregnancy-associated plasma protein-A (PAPP-A) levels determined during the first trimester as part of combined screening for aneuploidy carried out in pregnant women. We carried out a single-centre study including pregnant women who were being followed up by the Obstetrics Service Care Units of the XXI de Santiago de Compostela e Barbanza Foundation, who gave birth from March 1, 2015, to March 1, 2017, and who had undergone their first-trimester combined chromosomopathy screening. The sample included a total of 2794 women. We found a significant correlation between MoM PAPP-A and foetal birth weight. When MoM PAPP-A was measured at extremely low levels (< 0.3) during the first trimester, the OR for giving birth to a foetus with weight < p10, adjusting for gestational age and sex, was 2.74. For low levels of MoM PAPP-A (0.3-0.44), the OR was 1.52. With regard to the value of MOM PAPP-A levels as a predictor of foetal macrosomia, a correlation could be observed with elevated levels, although this was not statistically significant. PAPP-A determined during the first trimester acts as a predictor of foetal weight at term as well as for foetal growth disorders.

Dysregulation of insulin-like growth factor-1 signaling in postnatal bone elongation

Insulin-like growth factor-1 (IGF-1) is a critical modulator of cell growth and survival, making it a central part of maintaining essentially every biological system in the body. Knowledge of the intricate mechanisms involved in activating IGF-1 signaling is not only key to understanding basic processes of growth and development, but also for addressing diseases, such as cancer and diabetes. This brief review explores how dysregulation of normal IGF-1 signaling can impact growth by examining its role in postnatal bone elongation. IGF-1 actions are dysregulated in autoimmune diseases, such as juvenile idiopathic arthritis and chronic kidney disease, which results in growth stunting. Conversely, childhood obesity results in growth acceleration, premature growth cessation, and ultimately, diminished bone quality, while systemic IGF-1 levels remain normal. Understanding the role of IGF-1 signaling in normal and dysregulated growth can add to other studies that address how this system regulates chronic diseases.

m6A mRNA methylation regulates the ERK/NF-κB/AKT signaling pathway through the PAPPA/IGFBP4 axis to promote proliferation and tumor formation in endometrial cancer

N6-methyladenosine (m6A) mRNA methylation has been considered a gene modulatory mechanism involved in disease progression and carcinogenesis. Herein, we aimed to explore the specific mechanism of m6A mRNA methylation in endometrial cancer. RT-qPCR was implemented to test the clinical correlation between m6A methylation and endometrial cancer. Bioinformatics analysis was performed to screen the genes related to endometrial cancer, and SRAMP was utilized for the prediction of m6A targets. Western blot assay and MeRIP-qPCR experiments were conducted to verify the effect of m6A methylation on the candidate genes and the signaling pathways involved in the occurrence of endometrial cancer. m6A-seq, RT-qPCR, and polysome profiling were used to confirm the mechanisms of m6A methylation in modulating related genes and pathways. The levels of m6A methylation, METTL3, and IGFBP4 were reduced in tumor tissues of patients with endometrial cancer, and SRAMP analysis confirmed that IGFBP4 and PAPPA had m6A methylation sites. Reduced m6A methylation promoted endometrial cancer cell progression and tumor formation in vivo. m6A methylation of RNA in endometrial cancer cells directly modulated IGFBP4 and PAPPA expression. m6A methylation regulated the PAPPA/IGFBP4 axis, thereby influencing endometrial cancer through the NF-κB and ERK signaling pathways. Knockdown of PAPPA or overexpression of IGFBP4 in endometrial cancer cells partially reduced disease progression caused by reduced m6A methylation. This research suggests that m6A mRNA methylation modulates the ERK/NF-κB/AKT signaling pathway through the PAPPA/IGFBP4 axis to induce cell proliferation and tumor formation in endometrial cancer. 1. METTL3 expressed modestly and m6A methylation of IGFBP4 and PAPPA mRNAs decreased in endometrial cancer; 2. YTHDF1-mediated IGFBP4 translation was reduced in HEC-1-A and AN3CA cells, and YTHDF2-mediated PAPPA mRNA degradation was blunted but its protein expression increased; 3. Increased PAPPA and reduced IGFBP4 activated IGF1-induced ERK, AKT, and NF-κB pathways by binding IGFR, thereby promoting cancer cell malignancy.

Heritability and circulating concentrations of pregnancy-associated plasma protein-A and stanniocalcin-2 in elderly monozygotic and dizygotic twins

Introduction

Pregnancy-associated plasma protein-A (PAPP-A) is an IGF-activating enzyme suggested to influence aging-related diseases. However, knowledge on serum PAPP-A concentration and regulation in elderly subjects is limited. Therefore, we measured serum PAPP-A in elderly same-sex monozygotic (MZ) and dizygotic (DZ) twins, as this allowed us to describe the age-relationship of PAPP-A, and to test the hypothesis that serum PAPP-A concentrations are genetically determined. As PAPP-A is functionally related to stanniocalcin-2 (STC2), an endogenous PAPP-A inhibitor, we included measurements on STC2 as well as IGF-I and IGF-II.

Methods

The twin cohort contained 596 subjects (250 MZ twins, 346 DZ twins), whereof 33% were males. The age ranged from 73.2 to 94.3 (mean 78.8) years. Serum was analyzed for PAPP-A, STC2, IGF-I, and IGF-II by commercial immunoassays.

Results

In the twin cohort, PAPP-A increased with age (r=0.19; P<0.05), whereas IGF-I decreased (r=-0.12; P<0.05). Neither STC2 nor IGF-II showed any age relationship. When analyzed according to sex, PAPP-A correlated positively with age in males (r=0.18; P<0.05) and females (r=0.25; P<0.01), whereas IGF-I correlated inversely in females only (r=-0.15; P<0.01). Males had higher levels of PAPP-A (29%), STC2 (18%) and IGF-I (19%), whereas serum IGF-II was 28% higher in females (all P<0.001). For all four proteins, within-pair correlations were significantly higher for MZ twins than for DZ twins, and they demonstrated substantial and significant heritability, which after adjustment for age and sex averaged 59% for PAPP-A, 66% for STC2, 58% for IGF-I, and 52% for IGF-II.

Discussion

This twin study confirms our hypothesis that the heritability of PAPP-A serum concentrations is substantial, and the same is true for STC2. As regards the age relationship, PAPP-A increases with age, whereas STC2 remains unchanged, thereby supporting the idea that the ability of STC2 to inhibit PAPP-A enzymatic activity decreases with increasing age.

BMPER Improves Vascular Remodeling and the Contractile Vascular SMC Phenotype

Dedifferentiated vascular smooth muscle cells (vSMCs) play an essential role in neointima formation, and we now aim to investigate the role of the bone morphogenetic protein (BMP) modulator BMPER (BMP endothelial cell precursor-derived regulator) in neointima formation. To assess BMPER expression in arterial restenosis, we used a mouse carotid ligation model with perivascular cuff placement. Overall BMPER expression after vessel injury was increased; however, expression in the tunica media was decreased compared to untreated control. Consistently, BMPER expression was decreased in proliferative, dedifferentiated vSMC in vitro. C57BL/6_Bmper+/- mice displayed increased neointima formation 21 days after carotid ligation and enhanced expression of Col3A1, MMP2, and MMP9. Silencing of BMPER increased the proliferation and migration capacity of primary vSMCs, as well as reduced contractibility and expression of contractile markers, whereas stimulation with recombinant BMPER protein had the opposite effect. Mechanistically, we showed that BMPER binds insulin-like growth factor-binding protein 4 (IGFBP4), resulting in the modulation of IGF signaling. Furthermore, perivascular application of recombinant BMPER protein prevented neointima formation and ECM deposition in C57BL/6N mice after carotid ligation. Our data demonstrate that BMPER stimulation causes a contractile vSMC phenotype and suggest that BMPER has the potential for a future therapeutic agent in occlusive cardiovascular diseases.

Exosomes Promote Atherosclerosis Progression by Regulating Circ_100696/miR-503-5p/PAPPA Axis-Mediated Vascular Smooth Muscle Cells Proliferation and Migration

Circular RNAs (circRNAs) are known to play a crucial role in the progression of atherosclerosis (AS). In this study, we aim to explore the function of oxidized low-density lipoprotein (ox-LDL)-induced macrophage-derived exosomal circ_100696 in AS.THP-1 macrophages were induced by ox-LDL to mimic AS cell model. A quantitative real-time polymerase chain reaction (qRT-PCR) assay was applied to determine the expression of circ_100696, microRNA-503-5p (miR-503-5p), and pregnancy-associated plasma protein A (PAPPA). The morphology and size distribution of exosomes were examined by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). Western blot assay was performed for protein levels. Cell proliferation was assessed using 5-ethynyl-2'-deoxyuridine (EdU) assay. Flow cytometry analysis was performed to analyze the cell cycle. Wound-healing assay and transwell assay were done to examine cell migration. RNA pull-down assay, dual-luciferase reporter assay, and RNA immunoprecipitation (RIP) assay were employed to analyze the relationship among circ_100696, miR-503-5p, and PAPPA.Circ_100696 level was increased in ox-LDL-induced THP-1 macrophages and ox-LDL-treated THP-1 macrophage-derived exosomes (OM-Exo). OM-Exo promoted the proliferation, cell cycle, and migration of vascular smooth muscle cells (VSMCs). Circ_100696 was upregulated in VSMCs cocultured with OM-Exo. Circ_100696 knockdown reversed the effects of OM-Exo on VSMC proliferation and migration. Circ_100696 was demonstrated to function as the sponge for miR-503-5p, and miR-503-5p directly targeted PAPPA. Circ_100696 overexpression facilitated VSMC proliferation and migration, with miR-503-5p upregulation or PAPPA silencing reversing these effects. Moreover, circ_100696 overexpression promoted PAPPA expression by targeting miR-503-5p.OM-Exo promoted VSMC growth and migration by regulating the circ_100696/miR-503-5p/PAPPA axis, thereby promoting AS progression.

Structural insights into the covalent regulation of PAPP-A activity by proMBP and STC2

Originally discovered in the circulation of pregnant women as a protein secreted by placental trophoblasts, the metalloprotease pregnancy-associated plasma protein A (PAPP-A) is also widely expressed by many other tissues. It cleaves insulin-like growth factor-binding proteins (IGFBPs) to increase the bioavailability of IGFs and plays essential roles in multiple growth-promoting processes. While the vast majority of the circulatory PAPP-A in pregnancy is proteolytically inactive due to covalent inhibition by proform of eosinophil major basic protein (proMBP), the activity of PAPP-A can also be covalently inhibited by another less characterized modulator, stanniocalcin-2 (STC2). However, the structural basis of PAPP-A proteolysis and the mechanistic differences between these two modulators are poorly understood. Here we present two cryo-EM structures of endogenous purified PAPP-A in complex with either proMBP or STC2. Both modulators form 2:2 heterotetramer with PAPP-A and establish extensive interactions with multiple domains of PAPP-A that are distal to the catalytic cleft. This exosite-binding property results in a steric hindrance to prevent the binding and cleavage of IGFBPs, while the IGFBP linker region-derived peptides harboring the cleavage sites are no longer sensitive to the modulator treatment. Functional investigation into proMBP-mediated PAPP-A regulation in selective intrauterine growth restriction (sIUGR) pregnancy elucidates that PAPP-A and proMBP collaboratively regulate extravillous trophoblast invasion and the consequent fetal growth. Collectively, our work reveals a novel covalent exosite-competitive inhibition mechanism of PAPP-A and its regulatory effect on placental function.

Factors Associated with the Severity of Pregnancy-Related Hypertensive Disorder: Significance of Clinical, Laboratory, and Histopathological Features

The purpose of this paper is to evaluate the association of maternal clinical and laboratory features and placental histopathological changes with disease severity in pregnancy-related hypertensive disorders. From January 2021 to December 2021, clinical and laboratory data at the time of delivery and histopathological features of the placenta were collected from pregnant women with pregnancy-related hypertensive disorders at a single institution. The women were classified according to the pregnancy-related hypertensive disorder clinical severity, and each variable was compared accordingly. Gestational age-matched normotensive groups were also compared. Univariate and multivariate regression analyses were used to identify factors influencing pregnancy-related hypertensive disorder severity. Fifty-eight pregnancies were analyzed. Maternal albumin levels before delivery (beta coefficient −0.83, p = 0.043) and increased placental syncytial knots (beta coefficient 0.71, p = 0.026) are important parameters that are closely related to disease severity in women with pregnancy-related hypertensive disorders. The combination of albumin, PAPP-A, total bilirubin, and eGFR levels appears to be optimal for predicting pregnancy-related hypertensive disorder severity.

Research Advances in the Roles of Circular RNAs in Pathophysiology and Early Diagnosis of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) refers to different degrees of glucose tolerance abnormalities that occur during pregnancy or are discovered for the first time, which can have a serious impact on the mother and the offspring. The screening of GDM mainly relies on the oral glucose tolerance test (OGTT) at 24–28 weeks of gestation. The early diagnosis and intervention of GDM can greatly improve adverse pregnancy outcomes. However, molecular markers for early prediction and diagnosis of GDM are currently lacking. Therefore, looking for GDM-specific early diagnostic markers has important clinical significance for the prevention and treatment of GDM and the management of subsequent maternal health. Circular RNA (circRNA) is a new type of non-coding RNA. Recent studies have found that circRNAs were involved in the occurrence and development of malignant tumors, metabolic diseases, cardiovascular and cerebrovascular diseases, etc., and could be used as the molecular marker for early diagnosis. Our previous research showed that circRNAs are differentially expressed in serum of GDM pregnant women in the second and third trimester, placental tissues during cesarean delivery, and cord blood. However, the mechanism of circular RNA in GDM still remains unclear. This article focuses on related circRNAs involved in insulin resistance and β-cell dysfunction, speculating on the possible role of circRNAs in the pathophysiology of GDM under the current research context, and has the potential to serve as early molecular markers for the diagnosis of GDM.

Pregnancy-associated plasma protein-A (PAPPA) promotes breast cancer progression

Breast cancer is the most common malignancy in females and poses a significant health threat to women. Pregnancy-associated plasma protein-A (PAPPA) is highly expressed in pregnancy-associated breast cancer (PABC) tissues. In this study, we investigated the functional role of PAPPA in regulating the malignant phenotype of breast cancer. We first examined the expression level of PAPPA in PABC tissue and breast cancer cell lines using quantitative real-time polymerase-chain reaction (qRT-PCR) and western blot. Next, the functional role of PAPPA in breast cancer cells was validated by overexpression and knockdown experiments. Cell counting kit-8 (CCK-8) proliferation assay, 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay, wound healing and transwell invasion assay were used to examine cell proliferation, migration, and invasion ability. We further identified the microRNA target regulating PAPPA and studied its functional role. Finally, we examined the impact of PAPPA on the tumorigenesis and metastasis of breast cancer in mice model. Our study revealed that PAPPA was upregulated in PABC tissues and breast cancer cells. Overexpression of PAPPA promoted cell proliferation, motility, invasion, and epithelial-mesenchymal transition (EMT). We further identified miR-497-5p as a negative regulator of PAPPA, which suppressed cell proliferation, migration, invasion, and EMT in breast cancer cells. We also validated the oncogenic role of PAPPA in the mouse xenograft model. Collectively, our study suggests that PAPPA is an oncogenic protein highly expressed in PABC tissues and promotes breast cancer progression, which could serve as a novel therapeutic target for breast cancer.

Early Identification of the Maternal, Placental and Fetal Dialog in Gestational Diabetes and Its Prevention

Gestational diabetes mellitus (GDM) complicates between 5 and 12% of pregnancies, with associated maternal, fetal, and neonatal complications. The ideal screening and diagnostic criteria to diagnose and treat GDM have not been established and, currently, diagnostic use with an oral glucose tolerance test occurs late in pregnancy and produces poor reproducibility. Therefore, in recent years, significant research has been undertaken to identify a first-trimester biomarker that can predict GDM later in pregnancy, enable early intervention, and reduce GDM-related adverse pregnancy outcomes. Possible biomarkers include glycemic markers (fasting glucose and hemoglobin A1c), adipocyte-derived markers (adiponectin and leptin), pregnancy-related markers (pregnancy-associated plasma protein-A and the placental growth factor), inflammatory markers (C-reactive protein and tumor necrosis factor-α), insulin resistance markers (sex hormone-binding globulin), and others. This review summarizes current data on first-trimester biomarkers, the advantages, and the limitations. Large multi-ethnic clinical trials and cost-effectiveness analyses are needed not only to build effective prediction models but also to validate their clinical use.

Pregnancy-Associated Plasma Protein (PAPP)-A2 in Physiology and Disease

The growth hormone (GH)/insulin-like growth factor (IGF) axis plays fundamental roles during development, maturation, and aging. Members of this axis, composed of various ligands, receptors, and binding proteins, are regulated in a tissue- and time-specific manner that requires precise control that is not completely understood. Some of the most recent advances in understanding the implications of this axis in human growth are derived from the identifications of new mutations in the gene encoding the pregnancy-associated plasma protein PAPP-A2 protease that liberates IGFs from their carrier proteins in a selective manner to allow binding to the IGF receptor 1. The identification of three nonrelated families with mutations in the PAPP-A2 gene has shed light on how this protease affects human physiology. This review summarizes our understanding of the implications of PAPP-A2 in growth physiology, obtained from studies in genetically modified animal models and the PAPP-A2 deficient patients known to date.

A first trimester prediction model for large for gestational age infants: a preliminary study

Background

Large for gestational age infants (LGA) have increased risk of adverse short-term perinatal outcomes. This study aims to develop a multivariable prediction model for the risk of giving birth to a LGA baby, by using biochemical, biophysical, anamnestic, and clinical maternal characteristics available at first trimester.

Methods

Prospective study that included all singleton pregnancies attending the first trimester aneuploidy screening at the Obstetric Unit of the University Hospital of Modena, in Northern Italy, between June 2018 and December 2019.

Results

A total of 503 consecutive women were included in the analysis. The final prediction model for LGA, included multiparity (OR = 2.8, 95% CI: 1.6–4.9, p = 0.001), pre-pregnancy BMI (OR = 1.08, 95% CI: 1.03–1.14, p = 0.002) and PAPP-A MoM (OR = 1.43, 95% CI: 1.08–1.90, p = 0.013). The area under the ROC curve was 70.5%, indicating a satisfactory predictive accuracy. The best predictive cut-off for this score was equal to − 1.378, which corresponds to a 20.1% probability of having a LGA infant. By using such a cut-off, the risk of LGA can be predicted in our sample with sensitivity of 55.2% and specificity of 79.0%.

Conclusion

At first trimester, a model including multiparity, pre-pregnancy BMI and PAPP-A satisfactorily predicted the risk of giving birth to a LGA infant. This promising tool, once applied early in pregnancy, would identify women deserving targeted interventions.

Trial registration

ClinicalTrials.gov NCT04838431, 09/04/2021.

The relationship between serum pregnancy-associated plasma protein-A level in patients with aortic valve stenosis: a case-control study

OBJECTIVE

Calcific aortic stenosis (AS) is the most common form of calcific aortic valve disease. Many matrix metalloproteinase (MMP) have been shown to be expressed in aortic sclerosis and contribute to valve fibrosis and calcification. We investigated the relationship between Pregnancy-Associated Plasma Protein-A (PAPP-A) and AS.

METHODS

Sixty-one patients who referred to our cardiology clinic having AS diagnosed with transthoracic echocardiography and thirty control subjects were included in this study. The patient group was divided into two groups as mild and moderate-severe AS in terms of echocardiography results. Levels of C-reactive protein (CRP), insulin-like growth factor-1 (IGF-1) and PAPP-A were measured.

RESULTS

There was statistically significant difference between the patient and control group for PAPP-A (p = 0.009). In addition, the difference between MPV, IGF-1 and PAPP-A levels of control and AS groups was found. We found that serum PAPP-A level was an independent predictor of AS (B = 0.107, p = 0.01) by logistic regression analysis. In linear regression analysis, a significant correlation was found for AS severity with MPV, IGF-1 and PAPP-A levels, respectively (p = 0.025, p = 0.004, p = 0.035). It was revealed that PAPP-A and IGF-1 were negatively correlated (r = -0.327, p = 0.002). Correlation of serum PAPP-A level with echocardiographic parameters was no observed.

CONCLUSION

The level of PAPP-A may be a marker used in diagnosis rather than a marker used to determine the severity of AS. Studies with larger patient populations may further explain the role of PAPP-A in the diagnosis and treatment of AS.

Deletion of muscle Igf1 exacerbates disuse atrophy weakness in mice

Muscle atrophy occurs as a result of prolonged periods of reduced mechanical stimulation associated with injury or disease. The growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis and load sensing pathways can both aid in recovery from disuse through their shared downstream signaling, but their relative contributions to these processes are not fully understood. The goal of this study was to determine whether reduced muscle IGF-1 altered the response to disuse and reloading. Adult male mice with inducible muscle-specific IGF-1 deletion (MID) induced 1 wk before suspension and age-matched controls (CON) were subjected to hindlimb suspension and reloading. Analysis of muscle force, morphology, gene expression, signaling, and tissue weights was performed in nonsuspended (NS) mice, and those suspended for 7 days or reloaded following suspension for 3, 7, and 14 days. MID mice displayed diminished IGF-1 protein levels and muscle atrophy before suspension. Muscles from suspended CON mice displayed a similar extent of atrophy and depletion of IGF-1, yet combined loss of load and IGF-1 was not additive with respect to muscle mass. In contrast, soleus force generation capacity was diminished to the greatest extent when both suspension and IGF-1 deletion occurred. Recovery of mass, force, and gene expression patterns following suspension were similar in CON and MID mice, even though IGF-1 levels increased only in muscles from CON mice. Diminished strength in disuse atrophy is exacerbated with the loss of muscle IGF-1 production, whereas recovery of mass and strength upon reloading can occur even IGF-1 is low.NEW & NOTEWORTHY A mouse model with skeletal muscle-specific inducible deletion of Igf1 was used to address the importance of this growth factor for the consequences of disuse atrophy. Rapid and equivalent loss of IGF-I and mass occurred with deletion or disuse. Decrements in strength were most severe with combined loss of load and IGF-1. Return of mass and strength upon reloading was independent of IGF-1.

Male Differentiation in the Marine Copepod Oithona nana Reveals the Development of a New Nervous Ganglion and Lin12-Notch-Repeat Protein-Associated Proteolysis

Simple Summary

Copepods are tiny crustaceans and the most abundant animals on Earth; they also play a crucial role in the marine food chain. Among copepods, Oithona is one of most ecologically successful and is known for its differential behavior between males and females. The males adopt the strategy “live fast, die young”: they are constantly in motion to search for females, more vulnerable to predators, feed less, and have a higher mortality rate. In our study, we found the presence of a new male-specific ganglion in Oithona nana probably involved in female cues sensing. We also demonstrate the potential role of new Lin-12 Notch Repeat proteins in the development of this ganglion by interacting with proteins involved in the development of the nervous system. Thanks to our findings, we propose that the “live fast, die young” strategy of the O. nana males is optimized by the explosion of these Lin-12 Notch Repeat proteins in the male proteome involved in the development of the male-specific olfactory ganglion to increase female cue sensing and mating.

Abstract

Copepods are among the most numerous animals, and they play an essential role in the marine trophic web and biogeochemical cycles. The genus Oithona is described as having the highest density of copepods. The Oithona male paradox describes the activity states of males, which are obliged to alternate between immobile and mobile phases for ambush feeding and mate searching, respectively, while the female is less mobile and feeds less. To characterize the molecular basis of this sexual dimorphism, we combined immunofluorescence, genomics, transcriptomics, and protein–protein interaction approaches and revealed the presence of a male-specific nervous ganglion. Transcriptomic analysis showed male-specific enrichment for nervous system development-related transcripts. Twenty-seven Lin12-Notch Repeat domain-containing protein coding genes (LDPGs) of the 75 LDPGs identified in the genome were specifically expressed in males. Furthermore, some LDPGs coded for proteins with predicted proteolytic activity, and proteases-associated transcripts showed a male-specific enrichment. Using yeast double–hybrid assays, we constructed a protein–protein interaction network involving two LDPs with proteases, extracellular matrix proteins, and neurogenesis-related proteins. We also hypothesized possible roles of the LDPGs in the development of the lateral ganglia through helping in extracellular matrix lysis, neurites growth guidance, and synapses genesis.

Pregnancy-associated plasma protein-aa regulates endoplasmic reticulum-mitochondria associations

Endoplasmic reticulum (ER) and mitochondria form close physical associations to facilitate calcium transfer, thereby regulating mitochondrial function. Neurons with high metabolic demands, such as sensory hair cells, are especially dependent on precisely regulated ER-mitochondria associations. We previously showed that the secreted metalloprotease pregnancy-associated plasma protein-aa (Pappaa) regulates mitochondrial function in zebrafish lateral line hair cells (Alassaf et al., 2019). Here, we show that pappaa mutant hair cells exhibit excessive and abnormally close ER-mitochondria associations, suggesting increased ER-mitochondria calcium transfer. pappaa mutant hair cells are more vulnerable to pharmacological induction of ER-calcium transfer. Additionally, pappaa mutant hair cells display ER stress and dysfunctional downstream processes of the ER-mitochondria axis including altered mitochondrial morphology and reduced autophagy. We further show that Pappaa influences ER-calcium transfer and autophagy via its ability to stimulate insulin-like growth factor-1 bioavailability. Together our results identify Pappaa as a novel regulator of the ER-mitochondria axis.

Local IGF Bioactivity Associates with High PAPP-A Activity in the Pericardial Cavity of Cardiovascular Disease Patients

OBJECTIVE

Pregnancy-associated plasma protein-A (PAPP-A) has been suggested as a proatherogenic enzyme by its ability to locally increase insulin-like growth factor (IGF) activity through proteolytic cleavage of IGF binding protein-4 (IGFBP-4). Recently, stanniocalcin-2 (STC2) was discovered as an inhibitor of PAPP-A. This study aimed to investigate IGFBP-4, PAPP-A, and STC2 as local regulators of IGF bioactivity in the cardiac microenvironment by comparing levels in the pericardial fluid with those in the circulation of patients with cardiovascular disease.

METHODS

Plasma and pericardial fluid were obtained from 39 patients undergoing elective cardiothoracic surgery, hereof 15 patients with type 2 diabetes. Concentrations of IGF-I, intact and fragmented IGFBP-4, PAPP-A, and STC2 were determined by immunoassays and IGF bioactivity by a cell-based assay.

RESULTS

In pericardial fluid, the concentrations of total IGF-I, intact IGFBP-4, and STC2 were 72 ± 10%, 91 ± 5%, and 40 ± 24% lower than in plasma, while PAPP-A was 15 times more concentrated. The levels of the 2 IGFBP-4 fragments generated by PAPP-A and reflecting PAPP-A activity were elevated by more than 25%. IGF bioactivity was 62 ± 81% higher in the pericardial fluid than plasma. Moreover, pericardial fluid levels of both IGFBP-4 fragments correlated with the concentration of PAPP-A and with the bioactivity of IGF. All protein levels were similar in pericardial fluid from nondiabetic and diabetic subjects.

CONCLUSIONS

PAPP-A increases IGF bioactivity by cleavage of IGFBP-4 in the pericardial cavity of cardiovascular disease patients. This study provides evidence for a distinct local activity of the IGF system, which may promote cardiac dysfunction and coronary atherosclerosis.

Expression of the Insulin-like Growth Factor System in First- and Second-Trimester Human Embryonic and Fetal Gonads

CONTEXT

Insulin-like growth factor (IGF) signaling is crucial for sex differentiation and development of Leydig and Sertoli cells in fetal mice testes. No such information is available for human embryonic and fetal testes and ovaries.

OBJECTIVE

To investigate presence and activity of the IGF signaling system during human embryonic and fetal ovarian and testicular development.

DESIGN

Human embryonic and fetal gonads were obtained following legal terminations of pregnancies. Gene expression was assessed by microarray and qPCR transcript analyses. Proteins of the IGF system components were detected with immunohistochemistry and immunofluorescence analyses. Specimens were included from 2010 to 2017.

SETTING

University Hospital.

PATIENTS/PARTICIPANTS

Ovaries and testes from a total of 124 human embryos and fetuses aged 5 to 17 postconception weeks were obtained from healthy women aged 16 to 47 years resident in Denmark or Scotland.

MAIN OUTCOME MEASURES

Gene expression analysis using microarray was performed in 46 specimens and qPCR analysis in 56 specimens, both sexes included. Protein analysis included 22 specimens (11 ovaries, 11 testes).

RESULTS

IGF system members were detected in embryonic and fetal testes and ovaries, both at gene transcript and protein level. A higher expression of IGF regulators was detected in testes than ovaries, with a preferred localization to Leydig cells.

CONCLUSIONS

These data indicate that the IGF system is active during very early gestation, when it may have a regulatory role in Leydig cells.

Implications of the PAPP-A-IGFBP-IGF-1 pathway in the pathogenesis and treatment of polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common genetic diseases implicated in the development of end stage renal disease (ESRD). Although FDA has recently approved a drug against ADPKD, there is still a great need for development of alternative management strategies for ADPKD. Understanding the different mechanisms that lead to cystogenesis and cyst expansion in ADPKD is imperative to develop new therapies against ADPKD. Recently, we demonstrated that caloric restriction can prevent the development of cystic disease in animal models of ADPKD and through these studies identified a new role for pregnancy associated plasma protein-A (PAPP-A), a component of the insulin-like growth factors (IGF) pathway, in the pathogenesis of this disease. The PAPP-A-IGF pathway plays an important role in regulation of cell growth, differentiation, and transformation and dysregulation of this pathway has been implicated in many diseases. Several indirect studies support the involvement of IGF-1 in the pathogenesis of ADPKD. However, it was only recently that we described a direct role for a component of this pathway in pathogenesis of ADPKD, opening a new avenue for the therapeutic approaches for this cystic disease. The present literature review will critically discuss the evidence that supports the role of components of IGF pathway in the pathogenesis of ADPKD and discuss the pharmacological implications of PAPP-A-IGF axis in this disease.

Simultaneous Real-Time Detection of Pregnancy-Associated Plasma Protein-A and -A2 Using a Graphene Oxide-Based Surface Plasmon Resonance Biosensor

Background

Pregnancy-associated plasma protein-A and -A2 (PAPP-A and -A2) are principally expressed in placental trophoblasts and play a critical role in the regulation of fetal and placental growth. PAPP-A2 shares 45% amino acid similarity with PAPP-A. This study aimed to investigate the efficacy of real-time detection of PAPP-A and PAPP-A2 using a novel surface plasmon resonance (SPR) biosensor based on graphene oxide (GO).

Methods

Traditional SPR and GO-based SPR chips were fabricated to measure PAPP-A and PAPP-A2 concentrations. We compared SPR response curves of PAPP-A and PAPP-A2 between traditional SPR and GO-SPR biosensors. We also performed interference tests and specificity analyses among PAPP-A, PAPP-A2, and mixed interference proteins.

Results

The time to detect PAPP-A and PAPP-A2 was about 150 seconds with both traditional SPR and GO-SPR biosensors. Approximately double SPR angle shifts were noted with the GO-SPR biosensor compared to the traditional SPR biosensor at a PAPP-A and PAPP-A2 concentration of 5 μg/mL. The limit of detection of the GO-SPR biosensor was as low as 0.5 ng/mL for both PAPP-A and PAPP-A2. Interference testing revealed that almost all of the protein bonded on the GO-SPR biosensor with anti-PAPP-A from the mixture of proteins was PAPP-A, and that almost no other proteins were captured except for PAPP-A2. However, the SPR signal of PAPP-A2 (5.75 mdeg) was much smaller than that of PAPP-A (13.76 mdeg). Similar results were noted with anti-PAPP-A2, where almost all of the protein bonded on the GO-SPR biosensor was PAPP-A2. The SPR signal of PAPP-A (5.17 mdeg) was much smaller than that of PAPP-A2 (13.94 mdeg).

Conclusion

The GO-SPR biosensor could distinguish PAPP-A and PAPP-A2 from various mixed interference proteins with high sensitivity and specificity. It could potentially be used to measure PAPP-A and PAPP-A2 in clinical blood samples during pregnancy.

Pregnancy-associated plasma protein A as a predictor of all-cause mortality and cardiovascular events in patients with chronic kidney disease: a meta-analysis of prospective studies

INTRODUCTION

The aim of the study was to assess the association of elevated serum pregnancy associated plasma protein A (PAPP-A) and the risk of all-cause mortality, cardiovascular events and mortality due to infection in patients with chronic kidney disease (CKD).

MATERIAL AND METHODS

We systematically searched the Medline database up to March 2017. A random effects model was used to pool the relative risks (RRs) and their 95% confidence intervals (CIs). Sensitivity analysis and subgroup analysis were performed to explore the potential sources of heterogeneity.

RESULTS

Six studies involving 2034 subjects were included. The pooled RRs for the risk of all-cause mortality and cardiovascular events were 1.50 (95% CI: 1.17-1.92), 1.26 (95% CI: 0.95-1.69), respectively. Sensitivity analysis by excluding each individual study showed no influence on the main results. Subgroup analysis showed that age, male proportion, follow-up term, and assay methods were not modifiable factors.

CONCLUSIONS

Our study suggests that elevated serum PAPP-A is associated with the risk of all-cause mortality in patients with CKD.

Pregnancy-associated plasma protein-A2 levels are increased in early-pregnancy gestational diabetes: a novel biomarker for early risk estimation

AIM

To determine whether pregnancy-associated plasma protein-A2 levels are increased in early pregnancies complicated by gestational diabetes and whether gestation age influences levels. The possible use of pregnancy-associated plasma protein-A2 as a pre-screening biomarker to reduce the need for performing oral glucose tolerance tests in pregnant women was also investigated.

METHODS

Pregnant women were diagnosed with gestational diabetes in early pregnancy after a 2-hour 75 g oral glucose tolerance test in the catchment area of Skåne University Hospital, Lund, Sweden during 2011-2015 (n = 99). Age- and BMI-matched pregnant women without diabetes were recruited at similar gestational ages from maternal healthcare centres in the same geographical area during 2014-2015 to act as controls (n = 100). Circulating pregnancy-associated plasma protein-A2 was analysed in participant serum using commercially available enzyme-linked immunosorbent assay kits.

RESULTS

Circulating pregnancy-associated plasma protein-A2 was increased in women diagnosed with gestational diabetes [13.5 (9.58-18.8) ng/ml] compared with controls [8.11 (5.74-11.3) ng/ml; P < 0.001]. Pregnancy-associated plasma protein-A2 was associated with gestational diabetes independent of age, BMI, C-peptide and adiponectin (P < 0.001). Pregnancy-associated plasma protein-A2 as a pre-screening biomarker to identify women at a decreased risk of gestational diabetes resulted in a negative predictive value of 99.7%, with a sensitivity of 96% and a specificity of 30% at a cut-off level of 6 ng/ml.

CONCLUSIONS

This is the first study to show increased pregnancy-associated plasma protein-A2 levels in gestational diabetes. Pregnancy-associated plasma protein-A2 also shows promise as a pre-screening biomarker with the potential to reduce the need for performing oral glucose tolerance tests in early pregnancy. Future prospective cohort studies in a larger group of both high- and low-risk women are, however, needed to further confirm this observation.

Molecular mechanisms underlying nuchal hump formation in dolphin cichlid, Cyrtocara moorii

East African cichlid fishes represent a model to tackle adaptive changes and their connection to rapid speciation and ecological distinction. In comparison to bony craniofacial tissues, adaptive morphogenesis of soft tissues has been rarely addressed, particularly at the molecular level. The nuchal hump in cichlids fishes is one such soft-tissue and exaggerated trait that is hypothesized to play an innovative role in the adaptive radiation of cichlids fishes. It has also evolved in parallel across lakes in East Africa and Central America. Using gene expression profiling, we identified and validated a set of genes involved in nuchal hump formation in the Lake Malawi dolphin cichlid, Cyrtocara moorii. In particular, we found genes differentially expressed in the nuchal hump, which are involved in controlling cell proliferation (btg3, fosl1a and pdgfrb), cell growth (dlk1), craniofacial morphogenesis (dlx5a, mycn and tcf12), as well as regulators of growth-related signals (dpt, pappa and socs2). This is the first study to identify the set of genes associated with nuchal hump formation in cichlids. Given that the hump is a trait that evolved repeatedly in several African and American cichlid lineages, it would be interesting to see if the molecular pathways and genes triggering hump formation follow a common genetic track or if the trait evolved in parallel, with distinct mechanisms, in other cichlid adaptive radiations and even in other teleost fishes.

The utility of pregnancy associated plasma protein-A MoM values in prediction of term respiratory distress syndrome

This study aimed to investigate if the pregnancy associated plasma Protein-A (PAPP-A) multiples of median (MoM) levels could be used as a marker for the early prediction of RDS. The present study was designed with data gathered from 1773 patients who were referred to our institution for first trimester fetal chromosomal anomaly screening. First trimester PAPP-A MoM values and postnatal RDS occurrences in these pregnancies were retrospectively analysed. Of the 1773 neonates that were included in the study, 28 were delivered at or beyond 37 weeks, and 42 were delivered less than 37 weeks of gestation. In the group of neonates at or beyond 37 weeks, the cut-off value for RDS prediction was determined as 1.02. For this cut-off value, sensitivity was 72.41% and specificity was 91.84%. The area under curve (AUC) was determined to be statistically significant (p < .01). In conclusion, it was determined that in neonates that were delivered at or beyond 37 weeks of gestation, RDS occurrence could be predicted at a significant rate by utilising PAPP-A MoM values.IMPACT STATEMENTWhat is already known on this subject? Respiratory distress syndrome (RDS) is one of the major global healthcare problems, and continues to effect newborns despite the improvements in diagnosis and treatments of the disease. Studies have shown that pregnancy associated plasma protein-A (PAPP-A) has a critical role in cellular proliferation and differentiation, and it is closely associated with many physiological and pathological processes via regulation of local insulin like growth factor (IGF) concentrations. In majority of the past studies in the literature regarding PAPP-A values in pregnancies, the association between low values of PAPP-A MoM and maternal-fetal complications were investigated.What do the results of this study add? This study retrospectively examines the PAPP-A MoM levels and the occurence of RDS. In neonates that were delivered at or beyond 37 weeks of gestation, RDS occurrence could be predicted at a significant rate by utilising PAPP-A MoM values which was measured at the first trimester fetal anomaly screening test.What are the implications of these findings for clinical practice and/or further research? In the light of these findings, in order to reduce RDS related neonatal morbidity and mortality, pregnancies with PAPP-A MoM values greater than 1.02 at the first trimester fetal anomaly screening should be more closely followed up and a higher rate of suspicion should be kept for RDS occurrence.

Pregnancy-associated plasma protein-aa supports hair cell survival by regulating mitochondrial function

To support cell survival, mitochondria must balance energy production with oxidative stress. Inner ear hair cells are particularly vulnerable to oxidative stress; thus require tight mitochondrial regulation. We identified a novel molecular regulator of the hair cells’ mitochondria and survival: Pregnancy-associated plasma protein-aa (Pappaa). Hair cells in zebrafish pappaa mutants exhibit mitochondrial defects, including elevated mitochondrial calcium, transmembrane potential, and reactive oxygen species (ROS) production and reduced antioxidant expression. In pappaa mutants, hair cell death is enhanced by stimulation of mitochondrial calcium or ROS production and suppressed by a mitochondrial ROS scavenger. As a secreted metalloprotease, Pappaa stimulates extracellular insulin-like growth factor 1 (IGF1) bioavailability. We found that the pappaa mutants’ enhanced hair cell loss can be suppressed by stimulation of IGF1 availability and that Pappaa-IGF1 signaling acts post-developmentally to support hair cell survival. These results reveal Pappaa as an extracellular regulator of hair cell survival and essential mitochondrial function.

Pregnancy-Associated Plasma Protein A (PAPP-A) Concentration in Population of Healthy Young People: Interactions with Tobacco Smoke and Anti-oxidative Status

Pregnancy-associated plasma protein A (PAPP-A) is a high-molecular zinc-binding metalloproteinase that was first detected in the serum of pregnant women. It can also be detected in men and non-pregnant women. Recently, a growing interest in determining the concentration of PAPP-A as a marker of oxidative stress and atherosclerotic processes has been observed. Among the factors that could potentially influence the PAPP-A formation is the exposure to tobacco smoke. Some components of tobacco smoke have an immediate effect on the body and also direct influence on the cardiovascular system. The aim of this study was to evaluate the relation between PAPP-A concentration and either passive or active exposure to tobacco smoke in the population of medicine students (n = 152). The relation between PAPP-A concentration and chosen markers of inflammatory response and anti-oxidative processes was analyzed. The samples of serum, urine, and saliva were collected and main nicotine metabolites in urine samples were determined using ELISA technique. Comparison of the PAPP-A concentrations in the study group revealed that in the group of active smokers, the concentration of the protein was significantly higher than in the group of passive smokers (p = .04) and the group of not-exposed students (p = .006). PAPP-A concentration showed significant positive correlation with the values of FRAP and main nicotine metabolites. The evident influence of both active and passive tobacco smoke exposure on PAPP-A levels in the studied population of young people who in general are not included in the group of high-risk cardiovascular incidents, shows how important early prevention of anti-health behaviors is.

Transcription profile of the insulin-like growth factor signaling pathway during human ovarian follicular development

PURPOSE

The IGF signaling cascade exerts important regulatory functions in human ovarian folliculogenesis. The scope of this study was to evaluate the transcription profile of insulin-like growth factor (IGF) genes during human ovarian follicle development and to analyze follicle fluid levels of key IGF proteins.

METHODS

Gene expression profiling was performed with microarray gene analysis. The analysis was assessed from ovarian follicles and granulosa cells (GCs) obtained from isolated stage-specific human ovarian follicles, including preantral follicles, small antral follicles, and preovulatory follicles. Numerous genes involved in the IGF signaling pathway was evaluated and key genes were validated by qPCR from GCs. Protein levels of various IGF components of human follicular fluid (FF) were measured by ELISA and time-resolved immunofluorometric assays (TRIFMA).

RESULTS

The gene expression levels of PAPPA, IGF2, IGF receptors and intracellular IGF-activated genes increased with increasing follicle size. This was especially prominent in the late preovulatory stage where IGF2 expression peaked. Protein levels of intact IGF binding protein-4 decreased significantly in FF from large preovulatory follicles compared with small antral follicles concomitant with higher protein levels of PAPP-A. The IGF modulators IGF-2 receptor, IGFBPs, stanniocalcins, and IGF-2 mRNA binding proteins were all observed to be expressed in the different follicle stages.

CONCLUSIONS

This study confirms and highlights the importance of PAPP-A regulating bioactive IGF levels throughout folliculogenesis and especially for the high rate of granulosa cell proliferation and expression of key ovarian hormones important in the last part of the follicular phase of the menstrual cycle.

Prediction of large-for-gestational-age infants in pregnancies complicated by obesity: A population-based cohort study

INTRODUCTION

Infants born large for gestational age (LGA) have increased risks of adverse perinatal outcomes. Maternal obesity, defined as body mass index (BMI) ≥30 kg/m² , is one of the most prevalent risk factors for LGA and the proportion of pregnancies complicated by obesity is increasing. Early identification of women with BMI ≥30 kg/m² at increased risk of giving birth to an LGA infant may open possibilities for prevention, aiming at decreasing the incidence of LGA.

MATERIAL AND METHODS

A population-based cohort study using information from the first-trimester screening database, which was cross-linked with the Swedish Medical Birth Register. The database included 139 277 full-term singletons without fetal anomalies born between 2006 and 2015 to mothers without prepregnancy diabetes. Of these, 9.1% (n = 12 704) were infants of mothers with BMI ≥30 kg/m² . For all women with BMI ≥30 kg/m² , a prediction model for LGA to be used in early pregnancy was constructed based on information on biochemical markers and maternal characteristics. A similar model, as well as a prepregnancy prediction model, were constructed for parous women with BMI ≥30 kg/m² . In parous women, data from the previous pregnancy were also used. Receiver operating characteristic curve and area under curve (AUC) were calculated.

RESULTS

The predictive models for LGA in parous women with BMI ≥30 kg/m² prepregnancy and in early pregnancy had AUCs of 0.80 (95% CI 0.78-0.82) and 0.81 (95% CI 0.79-0.82), respectively. For all women with BMI ≥30 kg/m² , the prediction of LGA in early pregnancy had an AUC of 0.66 (95% CI 0.64-0.67).

CONCLUSIONS

Performance of the prepregnancy and early pregnancy prediction models for LGA in parous women with BMI ≥30 kg/m² was good. The predictive capacity was largely driven by previous child's birthweight. First-trimester measurements of fetal size did not improve the predictive capacity in parous women. Predictions of LGA in all women with BMI ≥30 kg/m² in early pregnancy, without taking previous child's birthweight into account, remain difficult.

Prediction of stillbirth in women with overweight or obesity-A register-based cohort study

OBJECTIVE

To develop a model for prediction of stillbirth after the 28th gestational week in singleton pregnancies of women with overweight or obesity.

METHOD

This is a register-based cohort study. The first trimester screening database including data from 2006 until 2015 was cross-linked with the Swedish Medical Birth Register and the Swedish Register of Total Population. The final study cohort comprised 145,319 pregnancies, out of which 45,859 pregnancies were complicated by overweight or obesity and without pre-gestational diabetes. There were in total 282 stillbirths. Prediction models for stillbirth in pregnancies with overweight or obesity were constructed based on maternal characteristics, pregnancy complications and biochemical markers. Receiver Operating Characteristic (ROC) and area under curve (AUC) were calculated, based on logistic regression analyses.

RESULTS

The prevalence of stillbirth was 1.6/1000 births and 2.6/1000 births in normal weight and overweight/obese women, respectively. The final predictive model had an AUC of 0.69 (95% CI: 0.64-0.74) with a sensitivity of 28% at a 90% fixed specificity.

CONCLUSIONS

It is possible to predict 28% of stillbirths in overweight or obese women, at a false positive rate of 10%. In particular, growth-restricted fetuses are at increased risk of stillbirth.

Placental volume at 11 to 14 gestational weeks in pregnancies complicated with fetal growth restriction and preeclampsia

OBJECTIVE

The study aims to evaluate the predictive value of first trimester placental volume in pregnancies destined to develop fetal growth restriction (FGR) and preeclampsia (PE).

METHODS

Prospective observational study including placentas from 34 FGR, 12 PE, 15 GH (gestational hypertension) pregnancies, and 265 controls. Placental volume (PV) was obtained using VOCAL technique, and a z score was calculated (z-PV). The association of PV with other first trimester variables and maternal characteristics was assessed with Spearman's correlation.

RESULTS

PV increased exponentially with crown-rump length (CRL) and was unrelated to maternal factors (weight, age, parity, and smoking status) as well as first trimester uterine artery Doppler, free β-hCG, nuchal translucency, or fetal heart rate. However, PV was positively associated with maternal height, CRL, PAPP-A, and birth weight. z-PV was a strong predictor for FGR with abnormal fetal Dopplers (AUC = 0.9472, P < 0.001). z-PV provided moderate prediction of FGR with normal fetal Dopplers (AUC = 0.8396, P < 0.001), PE (AUC = 0.8312, P < 0.001), and GH (AUC = 0.7640, P < 0.001). The addition of maternal weight, PAPP-A, β-hCG, and uterine artery Doppler improved our models.

CONCLUSION

At 11 to 14 weeks, PV is an independent predictor of pregnancy complications related to placental insufficiency, and the predictive ability is greater for FGR pregnancies with abnormal fetal Dopplers.

Olfactory receptor OR2AT4 regulates human hair growth

Olfactory receptors are expressed by different cell types throughout the body and regulate physiological cell functions beyond olfaction. In particular, the olfactory receptor OR2AT4 has been shown to stimulate keratinocyte proliferation in the skin. Here, we show that the epithelium of human hair follicles, particularly the outer root sheath, expresses OR2AT4, and that specific stimulation of OR2AT4 by a synthetic sandalwood odorant (Sandalore^®) prolongs human hair growth ex vivo by decreasing apoptosis and increasing production of the anagen-prolonging growth factor IGF-1. In contrast, co-administration of the specific OR2AT4 antagonist Phenirat^® and silencing of OR2AT4 inhibit hair growth. Together, our study identifies that human hair follicles can engage in olfactory receptor-dependent chemosensation and require OR2AT4-mediated signaling to sustain their growth, suggesting that olfactory receptors may serve as a target in hair loss therapy.

Increasing evidence suggest that olfactory receptors can carry additional functions besides olfaction. Here, Chéret et al. show that stimulation of the olfactory receptor ORT2A4 by the odorant Sandalore^® stimulates growth of human scalp hair follicles ex vivo, suggesting the use of ORT2A4-targeting odorants as hair growth-promoting agents.

First-trimester irisin and fetuin-A concentration in predicting macrosomia

Objective: We investigated the diagnostic value of first-trimester adipokines and placental markers in predicting macrosomia. Methods: Out of 328 women recruited during the prenatal diagnosis between 11th and 13th week of pregnancy and subjected to follow up until delivery, we selected 26 women who gave birth to macrosomic babies and 34 women who gave birth to normal weight neonates for the evaluation of first trimester serum levels of pregnancy associated plasma protein-A, free β-human chorionic gonadotropin, placental growth factor (PIGF), and selected adipokines. Results: The mothers of macrosomic infants had higher PIGF (p = .049) and irisin concentrations (p = .00003), and lower fetuin-A levels (p = .0002) than had the mothers of normal weight babies. Newborn's weight correlated positively with maternal irisin (R = 0.454, p = .0003) and negatively with fetuin-A concentrations (R = -0.497, p = .00005). Multiple regression analysis showed that only serum irisin concentration was a significant predictor of birth weight (β = 0.329, p = .03), explaining 14% of its variability. The sensitivity and the specificity of irisin concentration in predicting macrosomia were 0.769 and 0.794, respectively (AUC = 0.818 [95%CI: 0.708-0.928], p = .00001) with a proposed cut-off value of 1725.4 ng/ml. Conclusions: Our results suggest that mother's irisin may be an early biomarker of macrosomia.

The insulin-like growth factor system in multiple myeloma: diagnostic and therapeutic potential

Multiple myeloma (MM) is a highly heterogeneous plasma cell malignancy. The MM cells reside in the bone marrow (BM), where reciprocal interactions with the BM niche foster MM cell survival, proliferation, and drug resistance. As in most cancers, the insulin-like growth factor (IGF) system has been demonstrated to play a key role in the pathogenesis of MM. The IGF system consists of IGF ligands, IGF receptors, IGF binding proteins (IGFBPs), and IGFBP proteases and contributes not only to the survival, proliferation, and homing of MM cells, but also MM-associated angiogenesis and osteolysis. Furthermore, increased IGF-I receptor (IGF-IR) expression on MM cells correlates with a poor prognosis in MM patients. Despite the prominent role of the IGF system in MM, strategies targeting the IGF-IR using blocking antibodies or small molecule inhibitors have failed to translate into the clinic. However, increasing preclinical evidence indicates that IGF-I is also involved in the development of drug resistance against current standard-of-care agents against MM, including proteasome inhibitors, immunomodulatory agents, and corticoids. IGF-IR targeting has been able to overcome or revert this drug resistance in animal models, enhancing the efficacy of standard-of-care agents. This finding has generated renewed interest in the therapeutic potential of IGF-I targeting in MM. The present review provides an update of the impact of the different IGF system components in MM and discusses the diagnostic and therapeutic potentials.

Immuno-proteomic analysis of Trichinella spiralis, T. pseudospiralis, and T. papuae extracts recognized by human T. spiralis-infected sera

The present study explored potentially immunogenic proteins of the encapsulated (Trichinella spiralis) and non-encapsulated (T. pseudospiralis, T. papuae) species within the genus Trichinella. The somatic muscle larval extracts of each species were subjected to immunoblotting analysis using human T. spiralis-infected serum samples. Fifteen reactive bands of all three species were selected for further protein identification by liquid chromatography-tandem mass spectrometry, and their possible functions were ascertained using the gene ontology. Our findings showed immunogenic protein patterns with molecular mass in the range of 33-67 kDa. Proteomic and bioinformatic analysis revealed a wide variety of functions of 17 identified proteins, which are associated with catalytic, binding, and structural activities. Most proteins were involved in cellular and metabolic processes that contribute in the invasion of host tissues and the larval molting processes. The parasite proteins were identified as actin-5C, serine protease, deoxyribonuclease-2, and intermediate filament protein ifa-1. This information may lead to alternative tools for selection of potential diagnostic protein markers or aid in the design of vaccine candidates for prevention and control of Trichinella infection.

Physiological parameters regulating circulating levels of the IGFBP-4/Stanniocalcin-2/PAPP-A axis

BACKGROUND

Insulin Growth Factor Binding Protein 4 (IGFBP-4), Stanniocalcin-2 (STC-2) and Pregnancy-Associated Plasma Protein-A (PAPP-A) have a well-documented involvement in several physiological functions in humans but predictors of their circulating levels remain largely unknown. We aimed to identify anthropometric and biochemical parameters associated with circulating levels of IGFBP-4/STC-2/PAPP-A axis (ISPa) cross-sectionally and to study their day-night variation and their regulation in response to mixed meal and exercise.

METHODS

One hundred twenty two healthy individuals were evaluated cross-sectionally. Subgroups were subjected to standardized mixed meal ingestion in increasing quantities of 125mL or 250mL, or aerobic exercise for 30min, or day-night rhythm study. Main outcome measurements were circulating IGFBP-4 (total and intact), STC-2 and PAPP-A levels.

RESULTS

In multivariate models, the main predictors of serum total IGFBP-4 were PAPP-A and female gender. Intact IGFBP-4 was positively associated with serum creatinine. Height was inversely and female gender and % of total body fat were positively correlated with STC-2. PAPP-A decreased after ingesting both the 125mL (p=0.03) and 250mL quantities (p=0.001), while total IGFBP-4 was reduced after the 250mL quantity (p=0.001). Exercise increased STC-2 and PAPP-A levels (p<0.001 for both). Intact, and to a lesser extent total, IGFBP-4 displayed a cortisol-like day/night variation.

CONCLUSIONS

We report for the first time anthropometric and physiological modulators of ISPa serum levels in healthy humans.

Insulin-Like Growth Factor Bioactivity, Stanniocalcin-2, Pregnancy-Associated Plasma Protein-A, and IGF-Binding Protein-4 in Pleural Fluid and Serum From Patients With Pulmonary Disease

CONTEXT

Members of the insulin-like growth factor (IGF) system are primarily produced in the liver and secreted into the circulation, but they are also produced, recruited, and activated locally in tissues.

OBJECTIVE

To compare activity and concentrations of IGF system components in pleural fluid and blood.

DESIGN

Pathological pleural fluid, secondary to lung cancer or nonmalignant disease, and matching blood samples were collected from 24 patients ages 66.7 to 81.9 years.

METHODS

IGF-related proteins and cytokine levels were measured by immunoassays or immunoblotting. Bioactive IGF was measured by an IGF-1 receptor phosphorylation assay.

RESULTS

Total IGF-1 concentration did not differ between the compartments, but concentrations of free IGF-1 and bioactive IGF were more than threefold higher in pleural fluid than in corresponding serum samples (P = 0.0004), regardless of etiology. Median pregnancy-associated plasma protein-A (PAPP-A) and interleukin (IL)-6 levels were increased 47-fold and 143-fold, respectively, in pleural fluid compared with plasma (P < 0.0001). PAPP-A and IL-6 concentrations correlated positively (r = 0.46; P = 0.02). In pleural fluid, levels of PAPP-A-generated IGF binding protein-4 fragments correlated inversely with that of stanniocalcin-2 (r ≤ -0.42; P ≤ 0.05), a PAPP-A inhibitor; such correlations were absent in plasma.

CONCLUSION

Pathological pleural fluid is characterized by increased in vitro IGF bioactivity and elevated concentrations of PAPP-A, an IGF-activating proteinase. Thus, the tissue activity of the IGF system may differ substantially from that of the circulating IGF system. The correlation between IL-6 and PAPP-A indicates that inflammation plays a role in promoting local tissue IGF activity.

Pregnancy-Associated Plasma Protein A2 in Hemodialysis Patients: Significance for Prognosis

BACKGROUND

Pregnancy-associated plasma protein A (PAPP-A) is associated with adverse outcome of long-term hemodialysis patients (HD). The aim of the study was to test whether its homolog pregnancy-associated plasma protein A2 (PAPP-A2) can be detected in serum of HD patients and to define its significance.

METHODS

The studied group consisted of 102 long-term HD patients and 25 healthy controls. HD patients were prospectively followed up for five years (2009-2014). PAPP-A2 was measured by surface plasmon resonance biosensor, PAPP-A by time resolved amplified cryptate emission.

RESULTS

PAPP-A2, similarly as PAPP-A, was significantly increased in HD patients (median (interquartile range)) PAPP-A2: 6.2 (2.6-10.8) ng/mL, vs. 3.0 (0.7-5.9) ng/mL, p=0.006; PAPP-A: 18.9 (14.3-23.4) mIU/L, vs. 9.5 (8.4-10.5) mIU/L, p<0.001). In HD patients, PAPP-A2 correlated weakly but significantly with PAPP-A (τ=0.193, p=0.004). Unlike PAPP-A, PAPP-A2 was not significant for prognosis of HD patients when tested alone. There was a significant interaction between PAPP-A and PAPP-A2 on the mortality due to infection of HD patients (p=0.008). If PAPP-A was below median, mortality due to infection was significantly higher for patients with PAPP-A2 values above median than for patients with low PAPP-A2 levels (p=0.011).

CONCLUSION

PAPP-A2 is increased in HD patients and interacts with PAPP-A on patients´ prognosis.

Glucagon-like petide-2 acts on colon cancer myofibroblasts to stimulate proliferation, migration and invasion of both myofibroblasts and cancer cells via the IGF pathway

Glucagon-like peptide (GLP)-2 stimulates intestinal epithelial proliferation by acting, in part, via IGF release from sub-epithelial myofibroblasts. The response of myofibroblasts to GLP-2 remains incompletely understood. We studied the action of GLP-2 on myofibroblasts from colon cancer and adjacent tissue, and the effects of conditioned medium from these cells on epithelial cell proliferation, migration and invasion. GLP-2 stimulated proliferation, migration and invasion of myofibroblasts and the proliferative and invasive responses of cancer-associated myofibroblasts were greater than those of myofibroblasts from adjacent tissue. The responses were inhibited by an IGF receptor inhibitor, AG1024. Conditioned medium from GLP-2 treated myofibroblasts increased proliferation, migration and invasion of SW480, HT29, LoVo epithelial cells and these responses were inhibited by AG1024; GLP-2 alone had no effect on these cells. In addition, when myofibroblasts and epithelial cells were co-cultured in Ibidi chambers there was mutual stimulation of migration in response to GLP-2. The latter increased both IGF-1 and IGF-2 transcript abundance in myofibroblasts. Moreover, a number of IGF binding proteins (IGFBP-4, -5, -7) were identified in myofibroblast medium; in the presence of GLP-2 there was increased abundance of the cleavage products of IGBBP-4 and IGFBP-5 suggesting activation of a degradation mechanism that might increase IGF bioavailability. The data suggest that GLP-2 stimulates cancer myofibroblast proliferation, migration and invasion; GLP-2 acts indirectly on epithelial cells partly via increased IGF expression in myofibroblasts and partly, perhaps, by increased bioavailability through degradation of IGFBPs.

The IGF system in patients with type 2 diabetes: associations with markers of cardiovascular target organ damage

OBJECTIVE

Perturbations in the insulin-like growth factor (IGF) system may contribute to the accelerated cardiovascular disease (CVD) that occurs in patients with type 2 diabetes (T2D). However, it remains unknown whether the IGF system is also involved in the development of early, subclinical CVD. We characterised the IGF system in T2D patients and matched controls and examined the associations with markers of subclinical target organ damage.

METHODS

The study included 99 patients with recently diagnosed T2D and 99 age- and sex-matched controls. IGF-1 and IGFBP-1 to -4 were measured by immunoassays, as were pregnancy-associated plasma protein-A (PAPP-A) and the PAPP-A-generated N-terminal (NT) and C-terminal (CT) IGFBP-4 fragments, which are novel CVD risk markers. Arterial stiffness was evaluated by carotid-femoral pulse wave velocity (PWV). Cerebral white matter lesions (WMLs) and carotid artery remodelling were determined by MRI.

RESULTS

After multivariate adjustments, patients with T2D had lower concentrations of IGFBP-2, IGFBP-4, NT- and CT-IGFBP-4, when compared with controls. IGFBP-2 was inversely correlated to PWV in all subjects in multivariate analysis (P < 0.05), and IGFBP-3 was inversely associated with severity of WMLs (P < 0.05). The NT-IGFBP-4 fragment was associated with the degree of carotid artery remodelling among all subjects (regression coefficient (95% CI): 2.95 (0.70, 5.16), P = 0.011). Levels of NT- and CT-IGFBP-4 were reduced in T2D patients receiving metformin compared to those in controls and patients not receiving metformin.

CONCLUSIONS

Even in recently diagnosed and well-controlled T2D patients, IGF protein levels are altered and associated with CVD risk factors.