Haptoglobin phenotype in women with preeclampsia

The role of haptoglobin in the diagnosis of preeclampsia and HELLP syndrome and in predicting neonatal outcomes

OBJECTIVE

The study aimed to determine whether maternal serum haptoglobin values could have an effect on predicting diagnosis and neonatal outcomes in preeclampsia and HELLP syndrome.

MATERIALS AND METHODS

Hundred sixteen pregnant women who met the inclusion criteria were included in the study. To evaluate whether serum haptoglobin level in maternal blood could be used in early diagnosis of preeclampsia and HELLP syndrome, 49 pregnant women diagnosed with preeclampsia and 13 pregnant women diagnosed with HELLP syndrome were included in the study group, and 54 healthy pregnant women in the control group. The groups were compared regarding maternal serum haptoglobin level, platelet count, ALT, AST, LDH, and uric acid levels. Moreover, the age, obstetric histories, and newborn outcomes of all pregnant women were recorded and compared between groups.

RESULTS

The mean haptoglobin values were 0.29 ± 0.23 g/L in the HELLP syndrome group, 1.01 ± 0.52 g/L in the preeclampsia group, and 1.16 ± 0.37 g/L in the control group. The mean haptoglobin result was lower in the HELLP syndrome group compared to the preeclampsia and control groups (p < 0.001). While the differences between HELLP syndrome and the control and preeclampsia groups were statistically significant, no significant difference was determined between the preeclampsia and control groups. There was a significant positive correlation between haptoglobin value with the week of delivery, umbilical cord pH value, and the first and fifth-minute Apgar scores (p < 0.05).

CONCLUSION

It was concluded that haptoglobin values could be used together with other biochemical parameters to diagnose HELLP syndrome and predict newborn outcomes.

Sex-Specific Differences in Extracellular Vesicle Protein Cargo in Synovial Fluid of Patients with Osteoarthritis

Women are at a significantly higher risk of developing osteoarthritis (OA) compared to males. The pathogenesis of osteoarthritis (OA) in women is poorly understood. Extracellular vesicles (EVs) have been shown to play an essential role in numerous signaling processes during the pathogenesis of age-related diseases via paracrine signaling. Molecular profiling of the synovial fluid-derived EVs cargo in women may help in the discovery of novel biomarkers and therapeutics for the treatment of OA in women. Previously, we reported that synovial fluid-derived EV miRNA cargo differs in a sex-specific manner. This study aims to characterize synovial fluid-derived EV protein cargo in OA patients. Our data showed sex-specific EVs protein content in OA. We found haptoglobin, orosomucoid, and ceruloplasmin significantly up-regulated, whereas apolipoprotein down-regulated in female OA EVs. In males, we discovered β-2-glycoprotein, and complement component 5 proteins significantly up-regulated and Spt-Ada-Gcn5 acetyltransferase (SAGA)-associated factor 29 down-regulated in male OA EVs. Database for Annotation, Visualization, and Integrated Discovery (DAVID) and QuickGO analysis revealed OA-specific protein involvement in several biological, molecular, and cellular pathways, specifically in inflammatory processes. In conclusion, synovial fluid EV protein content is altered in a sex-specific manner with OA, explaining the increased prevalence and severity of OA in women.

The role of hemoglobin degradation pathway in preeclampsia: A systematic review and meta-analysis

INTRODUCTION

Overproduction of fetal hemoglobin by the placenta leading to increased consumption of endogenous heme scavenging proteins has been recently implicated as a novel pathway in the pathogenesis of preeclampsia. The aim of the present systematic review was to evaluate maternal serum levels of fetal hemoglobin, haptoglobin, heme oxygenase-1, hemopexin and α1-microglobulin, as well as haptoglobin phenotypes among preeclamptic and healthy pregnant women and assess their predictive role in the disease.

METHODS

Medline, Scopus, CENTRAL, Clinicaltrials.gov and Google Scholar databases were systematically searched from inception. All studies comparing levels of fetal hemoglobin or heme scavengers among preeclamptic and healthy pregnant controls were deemed eligible.

RESULTS

Twenty-three studies were included, with a total number of 7461 pregnant women. Quantitative synthesis was not conducted for the comparison of serum levels due to high heterogeneity. Current evidence suggests that preeclampsia is associated with increased levels of fetal hemoglobin and α1-microglobulin, as well as with lower levels of serum hemopexin. Data regarding serum haptoglobin and heme oxygenase-1 were conflicting, as the available evidence did not unanimously suggest a significant change of their levels in the disease. Network meta-analysis indicated no significant association for any of the haptoglobin phenotypes with preeclampsia development.

DISCUSSION

The present review suggests that preeclampsia may be associated with increased fetal hemoglobin and α1-microglobulin and decreased hemopexin levels, although inter-study heterogeneity was high. Future large-scale studies are needed to fully elucidate the predictive efficacy of these markers by introducing cut-off values and defining the optimal gestational age for sampling.

Haptoglobin Phenotype Modulates Lipoprotein-Associated Risk for Preeclampsia in Women With Type 1 Diabetes

CONTEXT

The incidence of preeclampsia (PE) is increased in women with diabetes (∼20% vs ∼5% in the general population), and first trimester lipoprotein profiles are predictive. Haptoglobin (Hp), a protein with functional genetic polymorphisms, has antioxidant, anti-inflammatory, and angiogenic effects. Among people with diabetes, the Hp 2-2 phenotype is associated with cardiorenal disease.

OBJECTIVE

To investigate whether Hp phenotype is associated with PE in type 1 diabetes mellitus (T1DM) and/or modulates lipoprotein-associated risks.

DESIGN AND SETTING

Multicenter prospective study of T1DM pregnancy.

PATIENTS

Pregnant women with T1DM (normal albuminuria, normotensive at enrolment, n = 47) studied at three visits, all preceding PE onset: 12.3 ± 1.9, 21.8 ± 1.5, and 31.5 ± 1.6 weeks' gestation (mean ± SD).

MAIN OUTCOME MEASURES

Hp phenotype and lipoprotein profiles in women with (n = 23) vs without (n = 24) subsequent PE.

RESULTS

Hp phenotype did not predict PE, but lipoprotein associations with subsequent PE were confined to women with Hp 2-2, in whom the following associations with PE were observed: increased low-density lipoprotein (LDL) cholesterol, LDL particle concentration, apolipoprotein B (APOB), triacylglycerol/high-density lipoprotein (HDL) cholesterol ratio, and APOB/apolipoprotein AI (APOA1) ratio; decreased HDL cholesterol, APOA1, large HDL particle concentration, and peripheral lipoprotein lipolysis (all P < 0.05). In women with one or two Hp-1 alleles, no such associations were observed.

CONCLUSIONS

In women with T1DM, although Hp phenotype did not predict PE risk, lipoprotein-related risks for PE were limited to those with the Hp 2-2 phenotype. Hp phenotype may modulate PE risk in diabetes.

siRNA-mediated NCAM1 gene silencing suppresses oxidative stress in pre-eclampsia by inhibiting the p38MAPK signaling pathway

Pre-eclampsia (PE), whose pathophysiology and etiology remain undefined, represents a leading consequence of fetal and maternal mortality and morbidity. Oxidative stress (OS) is recognized to involve in this disorder. In this study, we hypothesized that neural cell adhesion molecule 1 (NCAM1) gene silencing would suppress the OS in the pregnancy complicated by PE. Initially, clinical samples were collected for determination of NCAM1 expression in placental tissues and levels of OS products in blood. To assess the regulatory mechanism of NCAM1 knockdown on OS, we used small interfering RNA (siRNA) to silence NCAM1 expression in human umbilical vein endothelial cells (HUVECs). Next, cells were treated with or without hypoxia/reoxygenation to observe the level changes of OS products and p38 mitogen-activated protein kinase (p38MAPK) pathway-related genes. Finally, an evaluation of HUVEC migration and invasion abilities was conducted by wound-healing and transwell assays. Placenta of pregnancy with PE presented significantly increased NCAM1 expression in comparison to placenta of normal pregnancy. Meanwhile, enhanced OS in blood of pregnant women with PE was observed relative to women with normal pregnancy. siRNA-mediated knockdown of NCAM1 gene could inhibit the p38MAPK signaling pathway, repress OS, and promote cell migration and invasion in HUVECs, indicating that NCAM1 inhibition could reduce the influence of PE. Importantly, blocking the p38MAPK signaling pathway reversed the inhibitory role of NCAM1 gene silencing on PE. Collectively, this study defines potential role of NCAM1 gene silencing as a therapeutic target in PE through inhibiting OS and enhancing HUVEC migration and invasion by disrupting the p38MAPK signaling pathway.

Correlation of geographic distributions of haptoglobin alleles with prevalence of multiple sclerosis (MS) - a narrative literature review

We have proposed that the myelin damage observed in multiple sclerosis (MS) may be partly mediated through the long-term release and degradation of extracellular hemoglobin (Hb) and the products of its oxidative degradation [Cellular and Molecular Life Sciences, 71, 1789-1798, 2014]. The protein haptoglobin (Hpt) binds extracellular Hb as a first line of defense, and can serve as a vascular antioxidant. Humans have two different Hpt alleles: Hpt1 and Hpt2, giving either homozygous Hpt1-1 or Hpt2-2 phenotypes, or a heterozygous Hpt1-2 phenotype. We questioned whether those geographic regions with higher frequency of the Hpt2 allele (conversely, lower frequency of Hpt1 allele) would correlate with an increased incidence of MS, because different Hpt phenotypes will have variable anti-oxidative potentials in protecting myelin from damage inflicted by extracellular Hb and its degradation products. To test this hypothesis, we undertook a systematic analysis of the literature on reported geographic distributions of Hpt alleles to compare them with data reported in the World Health Organization Atlas of worldwide MS prevalence. We found the frequency of the Hpt1 allele to be low in European and North American countries with a high prevalence of MS, consistent with our hypothesis. However, this correlation was not observed in China and India, countries with the lowest Hpt1 frequencies, yet low reported prevalence of MS. Nevertheless, this work shows the need for continued refinement of geographic patterns of MS prevalence, including data on ethnic or racial origin, and for new clinical studies to probe the observed correlation and evaluate Hpt phenotype as a predictor of disease variability and progression, severity, and/or comorbidity with cardiovascular disorders.

Placental Proteomics Provides Insights into Pathophysiology of Pre-Eclampsia and Predicts Possible Markers in Plasma

Pre-eclampsia is a hypertensive disorder characterized by the new onset of hypertension >140/90 mmHg and proteinuria after the 20th week of gestation. The disorder is multifactorial and originates with abnormal placentation. Comparison of the placental proteome of normotensive (n = 25) and pre-eclamptic (n = 25) patients by gel-free proteomic techniques identified a total of 2145 proteins in the placenta of which 180 were differentially expressed (>1.3 fold, p < 0.05). Gene ontology enrichment analysis of biological process suggested that the differentially expressed proteins belonged to various physiological processes such as angiogenesis, apoptosis, oxidative stress, hypoxia, and placental development, which are implicated in the pathophysiology of pre-eclampsia. Some of the differentially expressed proteins were monitored in the plasma by multiple reaction monitoring analysis, which showed an increase in apolipoproteins A-I and A-II in gestational weeks 26-30 (2-fold, p < 0.01), while haptoglobin and hemopexin decreased in gestational weeks 26-30 and week 40/at delivery (1.8 fold, p < 0.01) in pre-eclamptic patients. This study provides a proteomic insight into the pathophysiology of pre-eclampsia. Identified candidate proteins can be evaluated further for the development of potential biomarkers associated with pre-eclampsia pathogenesis.

Preeclampsia and diabetes

Preeclampsia is diagnosed in women presenting with new onset hypertension accompanied by proteinuria or other signs of severe organ dysfunction in the second half of pregnancy. Preeclampsia risk is increased 2- to 4-fold among women with type 1 or type 2 diabetes. The limited number of pregnant women with preexisting diabetes and the difficulties associated with diagnosing preeclampsia in women with proteinuria prior to pregnancy are significant barriers to research in this high-risk population. Gestational diabetes mellitus (GDM) also increases preeclampsia risk, although it is unclear whether these two conditions share a common pathophysiological pathway. Nondiabetic women who have had preeclampsia are more likely to develop type 2 diabetes later in life. Among women with type 1 diabetes, a history of preeclampsia is associated with an increased risk of retinopathy and nephropathy. More research examining the pathophysiology, treatment, and the long-term health implications of preeclampsia among women with preexisting and gestational diabetes is needed.

In women with previous pregnancy hypertension, levels of cardiovascular risk biomarkers may be modulated by haptoglobin polymorphism

Preeclampsia (PE) may affect the risk for future cardiovascular disease. Haptoglobin (Hp), an acute phase protein with functional genetic polymorphism, synthesized in the hepatocyte and in many peripheral tissues secondary of oxidative stress of PE, may modulate that risk through the antioxidant, angiogenic, and anti-inflammatory differential effects of their genotypes. We performed a prospective study in 352 women aged 35 ± 5.48 years, which 165 had previous PE, 2 to 16 years ago. We studied demographic, anthropometric, and haemodynamic biomarkers such as C-reactive protein (CRP), myeloperoxidase (MPO), and nitric oxide metabolites (total and nitrites), and others associated with liver function (AST and ALT) and lipid profile (total LDL and cholesterol HDL, non-HDL, and apolipoproteins A and B). Finally, we study the influence of Hp genetic polymorphism on all these biomarkers and as a predisposing factor for PE and its remote cardiovascular disease prognosis. Previously preeclamptic women either hypertensive or normotensive presented significant differences in those risk biomarkers (MPO, nitrites, and ALT), whose variation may be modulated by Hp 1/2 functional genetic polymorphism. The history of PE may be relevant, in association with these biomarkers to the cardiovascular risk in premenopausal women.

Haptoglobin phenotype and abnormal uterine artery Doppler in a racially diverse cohort

OBJECTIVE

The anti-oxidant and proangiogenic protein haptoglobin (Hp) is believed to be important for implantation and pregnancy, although its specific role is not known. The three phenotypes (1-1, 2-1 and 2-2) differ in structure and function. Hp 2-2 is associated with increased vascular stiffness in other populations. We examined whether Hp phenotype is associated with abnormal uterine artery Doppler (UAD) in pregnancy.

METHODS

We conducted a secondary analysis of a preeclampsia prediction cohort nested within a larger placebo-controlled randomized clinical trial of antioxidants for prevention of preeclampsia. We determined Hp phenotype in 2184 women who completed UAD assessments at 17 weeks gestation. Women with notching were re-evaluated for persistent notching at 24 weeks' gestation. Logistic regression was used to assess differences in UAD indices between phenotype groups.

RESULTS

Hp phenotype did not significantly influence the odds of having any notch (p = 0.32), bilateral notches (p = 0.72), or a resistance index (p = 0.28) or pulsatility index (p = 0.67) above the 90th percentile at 17 weeks' gestation. Hp phenotype also did not influence the odds of persistent notching at 24 weeks (p = 0.25).

CONCLUSIONS

Hp phenotype is not associated with abnormal UAD at 17 weeks' gestation or with persistent notching at 24 weeks.

Trapping of human hemoglobin by haptoglobin: molecular mechanisms and clinical applications

SIGNIFICANCE

Haptoglobin (Hp) is an abundant plasma protein controlling the fate of hemoglobin (Hb) released from red blood cells after intravascular hemolysis. The complex formed between Hp and Hb is extraordinary strong, and once formed, this protein-protein association can be considered irreversible.

RECENT ADVANCES

A model of the Hp-Hb complex has been generated and the first steps toward understanding the mechanism behind the shielding effects of Hp have been taken. The clinical potential of the complex for modulating inflammatory reactions and for functioning as an Hb-based oxygen carrier have been described.

CRITICAL ISSUES

The three-dimensional structure of the Hp-Hb complex is unknown. Moreover, Hp is not a homogeneous protein. There are two common alleles at the Hp genetic locus denoted Hp1 and Hp2, which when analyzed on the protein levels result in differences between their physiological behavior, particularly in their shielding against Hb-driven oxidative stress. Additional cysteine residues on the α-subunit allow Hp2 to form a variety of native multimers, which influence the biophysical and biological properties of Hp. The multimeric conformations, in turn, also modulate the glycosylation patterns of Hp by steric hindrance.

FUTURE DIRECTIONS

A detailed analysis of the influence of Hp glycosylation will be instrumental to generate a deeper understanding of its biological function. Several pathological conditions also modify the glycan compositions allowing Hp to be potentially used as a marker protein for these disorders.

Haptoglobin phenotype, pre-eclampsia, and response to supplementation with vitamins C and E in pregnant women with type-1 diabetes

OBJECTIVE

The phenotype of the antioxidant and pro-angiogenic protein haptoglobin (Hp) predicts cardiovascular disease risk and treatment response to antioxidant vitamins in individuals with diabetes. Our objective was to determine whether Hp phenotype influences pre-eclampsia risk, or the efficacy of vitamins C and E in preventing pre-eclampsia, in women with type-1 diabetes.

DESIGN

This is a secondary analysis of a randomised controlled trial in which women with diabetes received daily vitamins C and E, or placebo, from 8 to 22 weeks of gestation until delivery.

SETTING

Twenty-five antenatal metabolic clinics across the UK (in north-west England, Scotland, and Northern Ireland).

POPULATION

Pregnant women with type-1 diabetes.

METHODS

Hp phenotype was determined in white women who completed the study and had plasma samples available (n = 685).

MAIN OUTCOME MEASURE

Pre-eclampsia.

RESULTS

Compared with Hp 2-1, Hp 1-1 (OR 0.59, 95% CI 0.30-1.16) and Hp 2-2 (OR 0.93, 95% CI 0.60-1.45) were not associated with significantly decreased pre-eclampsia risk after adjusting for treatment group and HbA1c at randomisation. Our study was not powered to detect an interaction between Hp phenotype and treatment response; however, our preliminary analysis suggests that vitamins C and E did not prevent pre-eclampsia in women of any Hp phenotype (Hp 1-1, OR 0.77, 95% CI 0.22-2.71; Hp 2-1, OR 0.81, 95% CI 0.46-1.43; Hp 2-2, 0.67, 95% CI 0.34-1.33), after adjusting for HbA1c at randomisation.

CONCLUSIONS

The Hp phenotype did not significantly affect pre-eclampsia risk in women with type-1 diabetes.

Haptoglobin phenotype, preeclampsia risk and the efficacy of vitamin C and E supplementation to prevent preeclampsia in a racially diverse population

Haptoglobin's (Hp) antioxidant and pro-angiogenic properties differ between the 1-1, 2-1, and 2-2 phenotypes. Hp phenotype affects cardiovascular disease risk and treatment response to antioxidant vitamins in some non-pregnant populations. We previously demonstrated that preeclampsia risk was doubled in white Hp 2-1 women, compared to Hp 1-1 women. Our objectives were to determine whether we could reproduce this finding in a larger cohort, and to determine whether Hp phenotype influences lack of efficacy of antioxidant vitamins in preventing preeclampsia and serious complications of pregnancy-associated hypertension (PAH). This is a secondary analysis of a randomized controlled trial in which 10,154 low-risk women received daily vitamin C and E, or placebo, from 9-16 weeks gestation until delivery. Hp phenotype was determined in the study prediction cohort (n = 2,393) and a case-control cohort (703 cases, 1,406 controls). The primary outcome was severe PAH, or mild or severe PAH with elevated liver enzymes, elevated serum creatinine, thrombocytopenia, eclampsia, fetal growth restriction, medically indicated preterm birth or perinatal death. Preeclampsia was a secondary outcome. Odds ratios were estimated by logistic regression. Sampling weights were used to reduce bias from an overrepresentation of women with preeclampsia or the primary outcome. There was no relationship between Hp phenotype and the primary outcome or preeclampsia in Hispanic, white/other or black women. Vitamin supplementation did not reduce the risk of the primary outcome or preeclampsia in women of any phenotype. Supplementation increased preeclampsia risk (odds ratio 3.30; 95% confidence interval 1.61-6.82, p<0.01) in Hispanic Hp 2-2 women. Hp phenotype does not influence preeclampsia risk, or identify a subset of women who may benefit from vitamin C and E supplementation to prevent preeclampsia.

Haptoglobin polymorphism affects nitric oxide bioavailability in preeclampsia

Studies showed elevated cell-free hemoglobin (Hb) in preeclampsia (PE), and Hb reacts with nitric oxide (NO), decreasing its bioavailability. Haptoglobin (Hp) is a polymorphic protein (Hp1-1, Hp2-1 and Hp2-2) that binds Hb to form a complex that is removed from circulation, thus preventing Hb-driven oxidative stress and NO scavenging. Hp protein products differ in biochemical and biophysical properties, which reflects on the Hb-Hp complex clearance rate. We hypothesized that Hp phenotypes modulate NO bioavailability by influencing NO consumption in PE. We studied 92 PE subjects and 105 normal pregnant women (NP). Hp genotypes were determined using real-time PCR. To assess NO bioavailability, we measured plasma nitrite using an ozone-based chemiluminescence assay. Plasma Hb and Hp were assessed with commercial immunoassays. A NO consumption assay was used to measure NO consumption. We found no differences in Hp genotype frequencies between PE and NP groups. Hp genotypes had no effects on plasma heme levels, NO consumption and plasma nitrite in NP. However, in PE, Hp2-1 and Hp2-2 were associated with higher plasma heme levels (48 and 55% higher, respectively; P<0.05), increased NO consumption (42 and 44% more, respectively; P<0.05) and lower plasma nitrite (39% less for Hp2-2; P<0.05) compared with Hp1-1. These findings indicate that although Hp genotype does not affect the risk of PE, Hp1-1 genotype may exert a protective role in PE by reducing NO scavenging, whereas Hp2-1 and Hp2-2 further may aggravate PE by reducing NO bioavailability.

Significance of platelet endothelial cell adhesion molecule-1 (PECAM-1) and intercellular adhesion molecule-1 (ICAM-1) expressions in preeclamptic placentae

Although preeclampsia (PE) is one of the most important problems affecting pregnant women, etiologic factors in its development are still unclear. We aimed to investigate the expression levels of platelet endothelial cell adhesion molecule-1 (PECAM-1) and intercellular adhesion molecule-1 (ICAM-1) in preeclamptic and control healthy placentas. Placental tissue samples were obtained after delivery from patients diagnosed with PE, and from normal term pregnants and analyzed by immunohistochemistry for the expression levels of the two adhesion molecules PECAM-1 and ICAM-1. A strong expression of PECAM-1 in endothelial cells lining the vessel walls of placental villi in placentas of control group was found, but the intensity of PECAM-1 expression was highly reduced in placentas of PE group (p = 0.017). Conversely, a strong expression of ICAM-1 was observed in placental villi in PE, significantly higher than that of normal placentas (p = 0.005). The findings of a decrease of PECAM-1 expression and an increase of ICAM-1 expression in preeclamptic placenta suggest the existence of functional roles of these adhesion molecules in the pathophysiology of PE, probably by contributing to the reduced trophoblast invasion and the increased vascular damage, respectively. Inhibiting ICAM-1 (i.e., with ICAM-1 monoclonal antibody) and promoting PECAM-1 expression may be good therapeutic approaches to prevent PE symptoms in the future.

Haptoglobin phenotype, angiogenic factors, and preeclampsia risk

OBJECTIVE

We sought to determine whether haptoglobin (Hp) phenotype is related to preeclampsia risk, or to plasma concentrations of soluble endoglin (sEng), soluble fms-like tyrosine kinase 1 (sFlt-1), and placental growth factor (PlGF).

STUDY DESIGN

Hp phenotype was retrospectively determined in primiparous women with uncomplicated pregnancies (n = 309), gestational hypertension (n = 215), and preeclampsia (n = 249). Phenotype was assessed by peroxidase staining following native polyacrylamide gel electrophoresis of hemoglobin-supplemented serum.

RESULTS

Compared with Hp 1-1, Hp 2-1 was associated with a significantly increased risk of preeclampsia (odds ratio, 2.11; 95% confidence interval, 1.07-4.18) and term preeclampsia (odds ratio, 2.45; 95% confidence interval, 1.07-5.83) in Caucasian women. Hp phenotype was not associated with preeclampsia risk in African Americans. Preeclamptic women had higher plasma sEng and sFlt-1, and lower PlGF, than control subjects. sEng, sFlt-1, and PlGF did not differ among women of different Hp phenotypes.

CONCLUSION

Hp 2-1 is associated with higher preeclampsia risk in primiparous Caucasian women.