Clinical differences between early-onset HELLP syndrome and early-onset preeclampsia during pregnancy and at least 6 months postpartum

Dysregulation of complement system in HELLP syndrome

OBJECTIVE

To investigate the expression of complement system's activation factors in patients with HELLP syndrome.

METHODS

A case-control study was performed. Sixteen HELLP syndrome patients, 32 severe preeclampsia patients, and 48 normal pregnancy women were involved in this studyELISA was used to test C1q, C4d, MBL, Bb, C3a, C5a, sC5b-9, s-Endoglin, and sflt-1 in the plasma.

RESULTS

The levels of C5a (P < 0.01) and sC5b-9 (P = 0.014) in HELLP syndrome were higher than those in severe preeclampsia patients.

CONCLUSIONS

The abnormal activation of the complement system is more significant in the pathogenesis of HELLP syndrome than in severe preeclampsia.

Oxidative Stress and Preeclampsia-Associated Prothrombotic State

Preeclampsia (PE) is a common obstetric disease characterized by hypertension, proteinuria, and multi-system dysfunction. It endangers both maternal and fetal health. Although hemostasis is critical for preventing bleeding complications during pregnancy, delivery, and post-partum, PE patients often develop a severe prothrombotic state, potentially resulting in life-threatening thrombosis and thromboembolism. The cause of this thrombotic complication is multi-factorial, involving endothelial cells, platelets, adhesive ligands, coagulation, and fibrinolysis. Increasing evidence has shown that hemostatic cells and factors undergo oxidative modifications during the systemic inflammation found in PE patients. However, it is largely unknown how these oxidative modifications of hemostasis contribute to development of the PE-associated prothrombotic state. This knowledge gap has significantly hindered the development of predictive markers, preventive measures, and therapeutic agents to protect women during pregnancy. Here we summarize reports in the literature regarding the effects of oxidative stress and antioxidants on systemic hemostasis, with emphasis on the condition of PE.

[HELLP Syndrome: clinical-analytical characteristics and evolution observed in two years of experience]

INTRODUCTION

HELLP syndrome (H: hemolysis, EL: elevated liver enzymes and LP: low platelets) is a form of severe preeclampsia (PE). The syndrome can be: complete or incomplete (with three analytical criteria, or only one or two); Class i, ii or iii (according platelets < 50,000; 50,000-100,000 or > 100,000/mm³); postpartum or antepartum; with early or late installation (before or after the 34nd week of gestation). We describe and analyze characteristics and evolution observed in hypertensive pregnant patients who developed HELLP.

MATERIAL AND METHODS

Retrospective cohort with observation period of two years. It included pregnant hypertensive women who developed HELLP, during the course of their hospitalization in the maternity hospital of our tertiary care hospital.

RESULTS

It included 318 hypertensive pregnant women. We observed 28 HELLP. Maternal age was 25.8 ±7.2 years and gestational age at diagnosis 31 ± 1 week. Hypertension was chronic in 4 and gestational in 24; eight had presented PE in the previous pregnancy. There were 10 complete and 18 incomplete syndromes; according to platelet disease there were 3 Class i, 16 Class ii and 9 Class iii. HELLP was postpartum in 3 and antepartum in 25: 18 early and 7 late. There were 17 patients who required intensive care and 10 developed complications linked to HELLP. No maternal deaths were recorded.

CONCLUSION

Presentation was variable, exhibiting mostly in gestational hypertension, antepartum and early. Incomplete form and class II thrombocytopenia were more frequent. Maternal complications were frequent but no deaths were observed.

The role of hepatic sinusoidal obstruction in the pathogenesis of the hepatic involvement in HELLP syndrome: Exploring the literature

AIM

This study aims to determine, based on existing data, whether the mechanism resulting in liver dysfunction in HELLP syndrome resembles that in Sinusoidal Obstruction Syndrome (SOS).

BACKGROUND

HELLP syndrome is a serious pregnancy disorder with high maternal and perinatal morbidity and mortality rates. Because of poor insight in its pathophysiology, particularly that of the liver involvement, clinical management is limited to symptomatic treatment, often followed by termination of pregnancy. SOS is a rare, potentially life-threatening complication of radio and/ or chemotherapy in the preparation of hematopoietic cell transplantation. The etiology of liver dysfunction in SOS is - unlike that in HELLP syndrome - better-understood and seems to be initiated by direct toxic damage and demise of endothelial cells, causing hepatic sinusoidal obstruction and ischemia.

METHODS

We searched Pubmed, Embase and Cochrane for reports on the etiology of HELLP and SOS. This yielded 73 articles, with 14 additional reports from the references listed in these articles.

RESULTS

The dysfunctional placenta in women developing HELLP initiates a cascade of events that eventually results in liver dysfunction. The placenta releases, besides anti-angiogenetic factors, also necrotic debris and cell-free DNA, a mixture that not only induces systemic endothelial dysfunction as in preeclampsia, but also a systemic inflammatory response. The latter aggravates the endothelio-toxic effects in the systemic cardiovascular bed, amplifying the already increased pro-thrombotic conditions. Particularly in microcirculations with extremely low shear forces, such as in the hepatic sinusoids, this will facilitate microthrombi formation and fibrin deposition eventually resulting in obstruction of the sinusoids similar as in SOS. The latter causes ischemic damage and progressive demise of hepatocytes.

CONCLUSION

The available information supports the concept that the liver damage in HELLP and SOS results from sinusoidal ischemia, presumably resulting from partially overlapping pathophysiological mechanisms.

Maternal Cardiovascular Risk Assessment 3-to-11 Years Postpartum in Relation to Previous Occurrence of Pregnancy-Related Complications

The aim of the present study was to assess the long-term outcomes of women 3-to-11 years postpartum in relation to the previous occurrence of pregnancy-related complications such as gestational hypertension (GH), preeclampsia (PE) and fetal growth restriction (FGR). Body mass index (BMI), waist circumference values, the average values of systolic (SBP) and diastolic (DBP) blood pressures and heart rate, total serum cholesterol levels, serum HDL (high-density lipoprotein) cholesterol levels, serum LDL (low-density lipoprotein) cholesterol levels, serum triglycerides levels, serum lipoprotein A levels, serum CRP (C-reactive protein) levels, plasma homocysteine levels, serum uric acid levels, individual and relative risks of having a heart attack or stroke over the next ten years were compared between groups (50 GH, 102 PE, 34 FGR and 90 normal pregnancies) and correlated with the severity of the disease with regard to clinical signs (25 PE without severe features, 77 PE with severe features), and delivery date (36 early PE, 66 late PE). The adjustment for potential covariates was made, where appropriate. At 3–11 years follow-up women with a history of GH, PE regardless of the severity of the disease and the delivery date, PE without severe features, PE with severe features, early PE, and late PE had higher BMI, waist circumferences, SBP, DBP, and predicted 10-year cardiovascular event risk when compared with women with a history of normotensive term pregnancy. In addition, increased serum levels of uric acid were found in patients previously affected with GH, PE regardless of the severity of the disease and the delivery date, PE with severe features, early PE, and late PE. Higher serum levels of lipoprotein A were found in patients previously affected with early PE. The receiver operating characteristic (ROC) curve analyses were able to identify a substantial proportion of women previously affected with GH or PE with a predisposition to later onset of cardiovascular diseases. Women with a history of GH and PE represent a risky group of patients that may benefit from implementation of early primary prevention strategies.

Homocysteinemia After Hypertensive Pregnancy Disorders at Term

BACKGROUND

Results from a number of long-term follow-up studies have suggested that hypertensive disorders in pregnancy are associated with increased risk of cardiovascular disease later in life. More recently, this putative relationship has been substantiated with findings of elevated cardiovascular risk factors, such as lipid profiles and glucose, in women with a history of hypertensive pregnancy disorders. Homocysteine is a sensitive indicator of increased risk but data on homocysteine levels in women with a history of hypertensive pregnancy disorders are inconsistent.

DESIGN

This cohort study included 279 women with a history of hypertensive pregnancy disorders at term and 85 women with a history of uncomplicated pregnancies who participated in the Hypitat Risk Assessment Study (HyRAS).

METHODS

Blood samples for total homocysteine determination were taken 2.5 years postpartum. Homocysteine levels were determined in plasma using an immunoassay.

RESULTS

Women with a history of hypertensive pregnancy disorders had significant higher median homocysteine levels (10.66 μmol/L) 2.5 years postpartum compared with women with a history uncomplicated pregnancies (9.82 μmol/L; p=0.002). Women with a history of hypertensive pregnancy disorders had a higher risk of having a homocysteine level in the highest quartile (odds ratio 3.4, 95% confidence interval 1.5-7.6).

CONCLUSION

At 2.5 years postpartum, women with a history hypertensive pregnancy disorders had higher homocysteine levels than women who had uncomplicated pregnancies. Although higher homocysteine levels might be a potential link between a history of hypertensive pregnancy disorders and increased cardiovascular disease risk later in life, the clinical implications remain an area for future research.

Associations between phenotypes of preeclampsia and thrombophilia

OBJECTIVES

Preeclampsia complicates 2-8% of all pregnancies. Studies on the association of preeclampsia with thrombophilia are conflicting. Clinical heterogeneity of the disease may be one of the explanations. The present study addresses the question whether different phenotypes of preeclampsia are associated with thrombophilia factors. Study design We planned a retrospective cohort study. From 1985 until 2010 women with preeclampsia were offered postpartum screening for the following thrombophilia factors: anti-phospholipid antibodies, APC-resistance, protein C deficiency and protein S deficiency, hyperhomocysteineamia, factor V Leiden and Prothrombin gene mutation. Hospital records were used to obtain information on phenotypes of the preeclampsia and placental histology.

RESULTS

We identified 844 women with singleton pregnancies who were screened for thrombophilia factors. HELLP complicated 49% of pregnancies; Fetal growth restriction complicated 61% of pregnancies. Early delivery (<34th week) occurred in 71% of pregnancies. Any thrombophilia factor was present in 29% of the women. Severe preeclampsia was associated with protein S deficiency (p=0.01). Fetal growth restriction was associated with anti-phospholipid antibodies (p<0.01). Early onset preeclampsia was associated with anti-phospholipid antibodies (p=0.01). Extensive placental infarction (>10%) was associated with anti-phospholipid antibodies (p<0.01). Low placental weight (<5th percentile) was associated with hyperhomocysteineamia (p=0.03). No other associations were observed.

CONCLUSIONS

Early onset preeclampsia, especially if complicated by fetal growth restriction, are associated with anti-phospholipid antibodies. Other phenotypes of preeclampsia, especially HELLP syndrome, were not associated with thrombophilia. We advise only to test for anti-phospholipid antibodies after early onset preeclampsia, especially if complicated by fetal growth restriction. We suggest enough evidence is presented to justify no further studies are needed.

Hypertension in pregnancy is associated with elevated homocysteine levels later in life

OBJECTIVE

Hyperhomocysteinemia is associated with an elevated cardiovascular disease risk. We examined whether women with a history of hypertension in pregnancy are more likely to have a high level of serum homocysteine decades after pregnancy.

STUDY DESIGN

Serum homocysteine was measured at a mean age of 60 years in nulliparous women (n = 216), and women with a history of normotensive (n = 1825) or hypertensive (n = 401) pregnancies who participated in the Genetic Epidemiology Network of Arteriopathy (GENOA) study. Relationships between homocysteine and pregnancy history were examined by linear and logistic regression, controlling for multiple covariates including personal and family history of hypertension, diabetes, obesity, tobacco use, and demographics.

RESULTS

A history of hypertension in pregnancy, when compared with normotensive pregnancy, was associated with a 4.5% higher serum homocysteine level (P = .015) and 1.60-fold increased odds of having an elevated homocysteine (95% confidence interval, 1.15-2.21; P = .005) after adjusting for potentially confounding covariates. In contrast, a history of normotensive pregnancy, as compared with nulliparity, was associated with a 6.1% lower serum homocysteine level (P = .005) and a 0.49-fold reduced odds of elevated homocysteine levels (95% confidence interval, 0.32-0.74; P < .001).

CONCLUSION

Homocysteine levels decades after pregnancy are higher in women with a history of pregnancy hypertension, even after controlling for potential confounders. Thus, pregnancy history may prompt homocysteine assessment and risk modification in an attempt at primary prevention of cardiovascular disease.

Depleted mitochondrial DNA content in peripheral blood of women with a history of HELLP syndrome

OBJECTIVE

To test the hypothesis that a quantitative defect of maternal cellular mitochondria would play a role in the pathogenesis of HELLP syndrome.

STUDY DESIGN

Peripheral blood mitochondrial DNA (MtDNA) was measured in 20 non-pregnant women with a history of HELLP syndrome, 40 non-pregnant control subjects who had previous physiologic pregnancies, 59 subjects carrying physiologic pregnancies, seven pregnant women with a history of HELLP syndrome and five women in the active phase of the disease.

MAIN OUTCOME MEASURE

Peripheral blood Mt-DNA.

RESULTS

The median (interquartile range) mtDNA in women with a history of HELLP syndrome, in non-pregnant women who had previous physiologic pregnancies, in subjects carrying physiologic pregnancies, in pregnant women with a history of HELLP syndrome and in women in the active phase of the disease was 115 (81-194), 229 (199-319), 174 (136-211), 101 (82-178) and 92 (39-129) copies per nuclear DNA, respectively. Non-pregnant women with a history of HELLP syndrome had significantly lower levels than non-pregnant controls (p<0.001). Moreover, blood mtDNA was lower in pregnant women with a history of HELLP syndrome and in those in the active phase of the disease when compared to pregnant controls (p=0.002 and p=0.025, respectively).

CONCLUSIONS

Attenuated maternal mitochondrial function may favor HELLP syndrome development.

Maternal plasma concentrations of sST2 and angiogenic/anti-angiogenic factors in preeclampsia

OBJECTIVES

Angiogenic/anti-angiogenic factors have emerged as one of the promising biomarkers for the prediction of preeclampsia. Since not all patients with preeclampsia can be identified by these analytes, the search for additional biomarkers continues. The soluble form of ST2 (sST2), a protein capable of binding to interleukin (IL)-33 and thus contributing to a Th1-biased immune response, has been reported to be elevated in maternal plasma of women with preeclampsia. The aims of this study were to examine: (1) differences in maternal plasma concentrations of sST2 and IL-33 between women diagnosed with preeclampsia and those having uncomplicated pregnancies; (2) the relationship between sST2, umbilical and uterine artery Doppler velocimetry, and the severity of preeclampsia; and (3) the performance of sST2 and angiogenic/anti-angiogenic factors in identifying patients with preeclampsia at the time of diagnosis.

METHODS

This cross-sectional study included women with preeclampsia (n = 106) and women with an uncomplicated pregnancy (n = 131). Plasma concentrations of sST2, IL-33, soluble vascular endothelial growth factor receptor (sVEGFR)-1, soluble endoglin (sEng) and placental growth factor (PlGF) were determined by enzyme linked immune sorbent assay. Area under the receiver operating characteristic curve (AUC) for the identification of preeclampsia was examined for each analyte.

RESULTS

(1) Patients with preeclampsia had a higher mean plasma concentrations of sST2 than those with an uncomplicated pregnancy (p < 0.0001), while no significant difference in the mean plasma concentration of IL-33 between the two groups was observed; (2) the magnitude of this difference was greater in early-onset, compared to late-onset disease, and in severe compared to mild preeclampsia; (3) sST2 plasma concentrations did not correlate with the results of uterine or umbilical artery Doppler velocimetry (p = 0.7 and p = 1, respectively) among women with preeclampsia; (4) sST2 correlated positively with plasma concentrations of sVEGFR1-1 and sEng (Spearman's Rho = 0.72 and 0.63; each p < 0.0001), and negatively with PlGF (Spearman's Rho = -0.56, p < 0.0001); and (5) while the AUC achieved by sST2 and angiogenic/anti-angiogenic factors in identifying women with preeclampsia at the time of diagnosis were non-significantly different prior to term (<37 weeks of gestation), thereafter the AUC achieved by sST2 was significantly less than that achieved by angiogenic/anti-angiogenic factors.

CONCLUSIONS

Preeclampsia is associated with increased maternal plasma concentrations of sST2. The findings that sST2 concentrations do not correlate with uterine or umbilical artery Doppler velocimetry in women with preeclampsia suggest that elevated maternal plasma sST2 concentrations in preeclampsia are not related to the increased impedance to flow in the utero-placental circulation. The performance of sST2 in identifying preeclampsia at the time of diagnosis prior to 37 weeks of gestation was comparable to that of angiogenic/anti-angiogenic factors. It remains to be elucidated if an elevation of maternal plasma sST2 concentrations in pregnancy is specific to preeclampsia.

Angiogenic factors and acute-phase proteins in serum samples of preeclampsia and HELLP patients: a matched-pair analysis

OBJECTIVES

To investigate the serum level distribution of angiogenic markers (PlGF, endoglin, sFlt-1) and acute-phase proteins (SAA, CRP) in patients with HELLP syndrome or preeclampsia (PE) including matched controls.

METHODS

The matching procedure revealed 46 controls for 23 HELLP cases, and 81 controls for 42 preeclamptic patients. Maternal serum concentrations were determined by immunoassays.

RESULTS

SAA and CRP levels were significantly higher in HELLP patients compared with controls. This finding was not observed in preeclamptic subgroup. Pro-angiogenic PlGF is significantly lower in PE and HELLP syndrome. Anti-angiogenic endoglin is significantly higher in PE and HELLP syndrome. The sFlt-1 analysis supports the anti-angiogenic shift in HELLP and preeclamptic patients, but with smaller differences between subgroups. The SAA/PlGF ratio showed the highest ROC value of all tested parameters in discrimination between HELLP and HELLP controls.

CONCLUSIONS

These findings support the concept that patients with HELLP syndrome have both an anti-angiogenic state and a pronounced inflammatory response, while patients with PE are characterized only by an anti-angiogenic shift.

Biochemistry of HELLP syndrome

The HELLP syndrome is a serious complication of pregnancy characterized by hemolysis (H), elevated liver (EL) enzymes, and low platelet (LP) count that occurs in 0.2-0.6% of all pregnancies and in 10-20% of cases with severe preeclampsia and frequently leads to adverse maternal and perinatal outcome. The exact pathobiology of HELLP syndrome has not been clearly defined. As it is considered a form or a complication of severe preeclampsia, it likely has its origin in aberrant placental development and function resulting in ischemia-producing oxidative stress. However, there is still a debate on whether HELLP must be considered a severe form of preeclampsia or a separate disease entity. It can be described as a placenta-induced disease, as is preeclampsia itself, but with a more acute and predominant inflammatory process typically targeting the liver and with a greater activation of the coagulation system. This occurs during a disordered immunologic process and may be due to a genetic predisposition. In this review, we discuss the main biochemical characteristics of HELLP syndrome, particularly focusing on molecular aspects of placental involvement and maternal systemic responses.