Introduction
Administration of dexamethasone to the hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome patients (10 mg intravenously [IV] every 12 hours) shortens the disease course and reduces maternal morbidity in patients treated at the University of Mississippi Medical Center (UMMC), associated with this severe form of preeclampsia. However, the pathophysiological mechanisms involved with this intervention remain unclear.
Objective
We sought to investigate the potential role of IV dexamethasone to restore the imbalance among antiangiogenic and inflammatory factors known to be significantly elevated in women with HELLP syndrome.
Study Design
This was a single-center prospective study of women diagnosed with HELLP syndrome who were treated for IV dexamethasone at UMMC. Blood was drawn prior to dexamethasone administration and again 12 and 24 hours after the initial dexamethasone administration. Enzyme-linked immune assays were used to measure circulating inflammatory cytokines and antiangiogenic factors. A repeated-measures analysis of variance was used to analyze the data collected before, after, and during dexamethasone administration.
Results
Seventeen women with HELLP syndrome were enrolled in this study. Dexamethasone significantly decreased evidence of hemolysis ( P = .002) and liver enzymes ( P = .003), and significantly increased platelets ( P = .0001) within 24 hours of administration. Circulating interleukin-6 levels after 24 hours were decreased ( P < .001); soluble fms-like tyrosine kinase-1 and soluble endoglin were also significantly decreased by 24 hours after dexamethasone administration ( P < .002 and P < .004, respectively). There were no significant differences in circulating levels of placental growth factor ( P = .886) due to dexamethasone administration. Angiotensin II receptor autoantibody levels were unchanged by dexamethasone administration.
Conclusion
We conclude that 1 important mechanism of dexamethasone administration is to blunt the release of both antiangiogenic and inflammatory factors suggested to play role in the pathophysiology of HELLP syndrome.
Hemolysis, elevated liver enzymes, and low platelet (HELLP) syndrome, a form of severe preeclampsia/eclampsia, affects 10% of women with preeclampsia in the United States and serves as a major contributor to maternal-perinatal morbidity and mortality. Recent evidence has demonstrated an imbalance between proangiogenic factors (ie, vascular endothelial growth factor and placental growth factors) and antiangiogenic factors (ie, soluble fms-like tyrosine kinase [sFlt-1] and soluble endoglin) in women with preeclampsia and/or HELLP syndrome.
During human preeclampsia and in animal models of the disease, sFlt-1 and soluble endoglin are associated with increased immune activation and elevations in inflammatory cytokines tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6). Furthermore, many studies have shown a close association between agonistic autoantibodies to the angiotensin II receptor (AT1-AA) and sFlt-1.
The Xia laboratory recently demonstrated that the severity of preeclampsia was tightly associated with the increase in AT1-AA and sFlt-1, thus indicating that these factors could potentially serve as biomarkers to predict the severity of preeclampsia during pregnancy. However, studies demonstrating high levels of AT1-AA in women with HELLP syndrome are lacking. Furthermore, studies linking antiangiogenic factors and soluble inflammatory markers during HELLP syndrome are sparse.
In recent years, many studies have reported conflicting results for the beneficial role of corticosteroids in the setting of HELLP syndrome. The use of dexamethasone to improve maternal outcome has been used in our tertiary care hospital for 2 decades. Recently we reported a study of 190 patients with HELLP syndrome who were treated with what is termed the Mississippi Protocol, an approach to patient management that includes intravenous (IV) dexamethasone administered immediately upon diagnosis of HELLP syndrome, and demonstrated a halt to disease progression as well as a reduction in new major maternal morbidity. Indeed, given the presence of inflammation in women with HELLP syndrome, we hypothesized that IV administration of dexamethasone could decrease the inflammation and/or antiangiogenic factors associated with HELLP syndrome.
Therefore, the aim of this study was to demonstrate that intravenous dexamethasone, as the core component of therapy for patients with HELLP syndrome, improves the clinical parameters of affected patients in association with decreased antiangiogenic factors and inflammatory cytokines. Both of these have been suggested to play a role in the pathophysiology of HELLP syndrome.
Materials and Methods
Study population
This was a prospective trial that involved pregnant patients with the diagnosis of HELLP syndrome admitted to the University of Mississippi Medical Center (Jackson, MS) between 2007 and 2011.
Inclusion criteria were patients presenting in the antepartum, intrapartum, or postpartum period with a primary indication of a HELLP syndrome. Patients are described as having met complete or incomplete HELLP syndrome criteria using the Mississippi classification systems for classes 1, 2, and 3 of HELLP syndrome. Class 1 HELLP syndrome (platelet count ≤50,000/μL, total serum lactic dehydrogenase [LDH] ≥600 IU/L, aspartate aminotransferase [AST] ≥70 IU/L), class 2 HELLP syndrome (platelet count 50,000 of ≤100,000/μL, total serum LDH ≥600 IU/L, AST ≥70 IU/L), and class 3 HELLP is characterized by (platelet count 100,000 of ≤150,000/μL, total serum LDH ≥600 IU/L, AST ≥70 IU/L). Partial or incomplete HELLP was defined as the presence of only 2 of the 3 major laboratory criteria to establish a diagnosis of complete HELLP syndrome.
Exclusion criteria included treatment with corticosteroids for any other maternal/fetal indication, having received corticosteroids within 10 days of diagnosis for any reason or having an active systemic infection that would contraindicate the use of corticosteroids.
Management of HELLP syndrome
HELLP syndrome was managed following the Mississippi Protocol which includes three major components: (1) magnesium sulfate by intravenous infusion primarily for eclampsia seizure prophylaxis and reduction of systemic vascular resistance through delivery and up to 24 hours postpartum with duration dependent on disease acuity and whether HELLP syndrome is first-evidenced postpartum; (2) blood pressure control using oral or intravenous medication (hydralazine or labetol) to sustain systolic blood pressure less than 160 mm Hg and diastolic blood pressure less than 100 mm Hg; and (3) IV dexamethasone 10 mg at 12 hour intervals until platelet normalization is trending toward 100,000 μL at which time 5 mg dexamethasone at 12 hour intervals is administered twice intravenously before cessation to minimize the risk of rebound thrombocytopenia. Importantly, the intravenous dexamethasone is initiated as soon as the diagnosis of HELLP syndrome is made in patients with class 1 or 2 HELLP syndrome or in patients with class 3 or partial HELLP syndrome complicated by eclampsia, severe systolic hypertension, severe epigastric pain, or a rapidly deteriorating clinical status.
Laboratory methods
Data collection included maternal clinical parameters (symptoms of headaches, right upper abdominal pain, blood pressure), measures of maternal morbidity (cardiopulmonary, hematocoagulation, hepatorenal, infectious, obstetric), laboratory values (platelet count, hematocrit, LDH, creatinine, AST, uric acid, cytokine, and vascular factors), and fetal outcome variables (gestational age at delivery, birthweight, Apgar scores, requirement for mechanical ventilation, other measures of neonatal morbidity). For the purposes of the current study, blood was drawn at the time of study admission (prior to corticosteroid administration) and at 12 and 24 hours after initial dexamethasone administration before the next dose was given.
Determination of cytokine and AT1-AA production
Plasma was collected and measured for angiogenic factors: sFlt-1, soluble endoglin, placental growth factor (PlGF) and inflammatory cytokines: IL-6, TNF-α. Commercial ELISA kits available from R&D Systems (Quantikine; R&D Systems, Minneapolis, MN) were used according to the manufacturer’s protocol. Sera immunoglobulin fractions were isolated from HELLP patients as previously described. AT1-AA activity was measured utilizing a bioassay that evaluates the beats/minute (bpm) of neonatal cardiomyocytes in culture.
Statistical analysis
Data are expressed as mean ± SEM. A repeated-measures analysis of variance was used to determine differences in clinical and circulating parameters before, during, and after dexamethasone administration, with a paired Student t test being used for post hoc analysis. A Student’s t test was also used to determine differences in clinical laboratory parameters between women with antepartum vs postpartum HELLP. Spearman calculation was used to determine whether there was a correlation between the final platelet count and the number of dexamethasone administrations before delivery. Percent change was calculated as ([value post dexamethasone-Time before dexamethasone]/value before dexamethasone) × 100. Values were considered statistically significant at P < .05.
Results
Patient population and demographics
During the study period 2007-2011, 19 female patients with a diagnosis of HELLP syndrome meeting eligibility criteria consented for enrollment in the current study. Of these, 17 completed the study, with blood drawn at baseline and approximately 12 and 24 hours after the initial IV dexamethasone administration.
Women enrolled in this study were similar regarding baseline demographic and pregnancy characteristics, with the exception of maternal race ( Table 1 ). Sixteen of 17 (94.1%) of the study participants were self-reported African American. Approximately 71% of the patients had cesarean deliveries in which the most common indications were elective repeat, failure to progress, and nonreassuring fetal heart rates. There was 1 patient with a previous history of eclampsia, who also had eclampsia in the current study. Seven women (41%) received both doses of dexamethasone and had blood drawn prior to delivery, 2 women (12%) received both doses of dexamethasone and had their last blood draw within 3 hours of delivery, 3 women (18%) received 1 dose of dexamethasone before delivery and had her last dose and last 2 blood draws after delivery. Five patients (29%) enrolled in the study developed HELLP syndrome during the postpartum period and did not receive any dexamethasone prior to delivery.
| Demographic | % (x/n) |
|---|---|
| n | 17 |
| Age, y | 24 ± 1.5 |
| Median (range) | 23 (18–40) |
| Race (% African American) | 94.1% (16/17) |
| Primigravida | 35.2% (6/17) |
| Gestational age at delivery, wks | 31.9 ± 1.2 |
| Median (range) | 32.6 (20.4–39) |
| Mode of delivery | |
| Primary cesarean | 33.3% (4/12) |
| Vaginal | 41.6% (5/12) |
| DX chronic hypertension | 29.4 (5/17) |
| Current Dx preeclampsia | 58.8% (10/17) |
| Previous DX preeclampsia in prior pregnancy | 18.2% (2/11) |
| Current DX of eclampsia | 11.7% (2/17) |
| Previous DX of eclampsia in prior pregnancy | 9.0% (1/11) |
| Class 1 HELLP syndrome | 35.2% (6/17) |
| Class 2 HELLP syndrome | 47.0% (8/17) |
| Class 3 HELLP syndrome | 17.6% (3/17) |
| Indicators of preeclampsia/HELLP syndrome | |
| Increasing blood pressure | 70.5% (12/17) |
| Headaches unrelieved with Tylenol | 11.7% (2/17) |
| Uric acid >6.0 mg/dL | 23.5% (4/17) |
| AST ≥70 IU/L | 82.3% (14/17) |
| Visual disturbance | 0% (0/17) |
| Thrombocytopenia | 17.6% (3/17) |
| Epigastric pain | 35.2% (6/17) |
| Proteinuria | 47.0% (8/17) |
| Disseminated intravascular coagulation | 5.8% (1/17) |
Biochemical parameters of HELLP syndrome
To determine whether there were differences in the clinical laboratory values of HELLP syndrome between women who developed HELLP in the antepartum vs postpartum period, we compared LDH, AST, and platelet values at study enrollment. At the time of study enrollment, there were no significant differences in platelet counts ( P = .114) or LDH ( P = .451) or AST levels ( P = .182, Figure 1 ). Because there were no significant differences in laboratory values between groups, all patients were analyzed together, independent of when they developed HELLP syndrome.
Dexamethasone improves clinical signs and laboratory values
Clinical findings indicated that systolic and diastolic blood pressures were significantly decreased at 12 ( P = .020; P = .011) and 24 ( P = .002; P = .014) hours after IV dexamethasone administration ( Table 2 ). With regard to laboratory values, IV dexamethasone significantly increased platelets after 12 ( P = .001) and 24 hours ( P = .0001; Figure 2 , A). The number of times dexamethasone was administered before delivery did not have a significant effect on the platelet count at the 24 hour blood draw ( P = .476; data not shown). There was not a significant difference in platelet count at 24 hours between the women who received both doses of dexamethasone before delivery (105,500 ± 5500 μL) and the women who received both doses and had their final blood draw before delivery ( P = .804; 111,714 ± 12,222 μL). There was not a correlation between the percent increase in platelet count from baseline to 24 hours after the initial dexamethasone dose and the number of times dexamethasone was administered before delivery (r = 0.4, P = .750).
| Parameter | Enrollment (n = 17) | 12 hours after (n = 17) | 24 hours after (n = 17) |
|---|---|---|---|
| Systolic blood pressure, mm Hg (range) | 156.9 ± 4.7 (128–190) | 138.4 ± 3.4 (120–155) a | 134.4 ± 2.1 (125–145) a |
| Diastolic blood pressure, mm Hg (range) | 93.5 ± 3.6 (69–115) | 82.2 ± 3.9 (60–107) a | 79.4 ± 3.1 (65–95) a |
| Platelets, μL | 80,647 ± 5576 | 93,706 ± 5818 a | 119,118 ± 6451 a , b |
| AST, IU/L | 195.5 ± 43.24 | 96.29 ± 16.1 a | 63.41 ± 8.9 a , b |
| LDH, IU/L | 1737 ± 152.7 | 1408 ± 98.7 a | 1193 ± 95.6 a , b |
| Creatinine, mg/dL | 0.75 ± 0.05 | 0.75 ± 0.05 | 0.78 ± 0.05 |
| Uric acid, mg/dL | 4.95 ± 0.49 | 5.67 ± 0.45 | 5.94 ± 0.52 a |
| Proteinuria indicated | 53% (9/17) | — | — |
a P < .05 compared with parameter value at enrollment;
b P < .05 compared with parameter value 12 hours after administration of dexamethasone.
Hematocrit significantly decreased in response to dexamethasone ( P = .0004) at 12 hours and ( P = .0001) after 24 hours ( Figure 2 , B). Serum LDH and AST levels both decreased 12 ( P = .004; P = .006) and 24 hours ( P = .002; P = .003) after dexamethasone administration and continued to significantly decrease after an additional dexamethasone treatment ( P = .005; P = .005; Figure 2 , C and D). There was not a significant change in creatinine levels because of dexamethasone ( P = .611; Table 2 ). Uric acid increased ( P = .05) 24 hours after dexamethasone administration but did not significantly change during the first 12 hours of dexamethasone treatment ( P = .098; Table 2 ). Fifty-three percent of patients had proteinuria at admission ( Table 2 ).
Antiangiogenic factors are decreased in response to dexamethasone
Circulating soluble endoglin was significantly decreased by 32.3% at12 hours (40.65 ± 5.07 ng/mL; P = .034) and by 62.8% at 24 hours (21.02 ± 4.71 ng/mL; P = .004) after dexamethasone administration compared with soluble endoglin levels at study enrollment (54.80 ± 6.08 ng/mL; Figure 3 , A). Administration of dexamethasone decreased circulating levels of the antiangiogenic factor, sFlt-1 by 25% at 12 hours (3839 ± 701.4 pg/mL; P = .020) and by 43.6% at 24 hours (2814 ± 578 pg/mL; P = .002) after administration compared with sFlt-1 levels at study enrollment (5213 ± 786 pg/mL; Figure 3 , B).
