Serum Amyloid A Levels Are Increased in Pre-Eclampsia

Serum amyloid A1 and pregnancy zone protein in pregnancy complications and correlation with markers of placental dysfunction

BACKGROUND

Hypertensive disorders of pregnancy (preeclampsia, gestational hypertension, and chronic hypertension), diabetes mellitus, and placental dysfunction confer an increased risk of long-term maternal cardiovascular disease. Preeclampsia is also associated with acute atherosis that involves lesions of uteroplacental spiral arteries, resembling early stages of atherosclerosis. Serum amyloid A1 is involved in hypercoagulability and atherosclerosis and may aggregate into amyloid-aggregations of misfolded proteins. Pregnancy zone protein may inhibit amyloid aggregation. Amyloid is involved in Alzheimer's disease and cardiovascular disease; it has been identified in preeclampsia, but its role in preeclampsia pathophysiology is unclear.

OBJECTIVE

We hypothesized that serum amyloid A1 would be increased and pregnancy zone protein decreased in hypertensive disorders of pregnancy and diabetic pregnancies and that serum amyloid A1 and pregnancy zone protein would correlate with placental dysfunction markers (fetal growth restriction and dysregulated angiogenic biomarkers) and acute atherosis.

STUDY DESIGN

Serum amyloid A1 is measurable in both the serum and plasma. In our study, plasma from 549 pregnancies (normotensive, euglycemic controls: 258; early-onset preeclampsia: 71; late-onset preeclampsia: 98; gestational hypertension: 30; chronic hypertension: 9; diabetes mellitus: 83) was assayed for serum amyloid A1 and pregnancy zone protein. The serum levels of angiogenic biomarkers soluble fms-like tyrosine kinase-1 and placental growth factor were available for 547 pregnancies, and the results of acute atherosis evaluation were available for 313 pregnancies. The clinical characteristics and circulating biomarkers were compared between the pregnancy groups using the Mann-Whitney U, chi-squared, or Fisher exact test as appropriate. Spearman's rho was calculated for assessing correlations.

RESULTS

In early-onset preeclampsia, serum amyloid A1 was increased compared with controls (17.1 vs 5.1 µg/mL, P<.001), whereas pregnancy zone protein was decreased (590 vs 892 µg/mL, P=.002). Pregnancy zone protein was also decreased in diabetes compared with controls (683 vs 892 µg/mL, P=.01). Serum amyloid A1 was associated with placental dysfunction (fetal growth restriction, elevated soluble fms-like tyrosine kinase-1 to placental growth factor ratio). Pregnancy zone protein correlated negatively with soluble fms-like tyrosine kinase-1 to placental growth factor ratio in all study groups. Acute atherosis was not associated with serum amyloid A1 or pregnancy zone protein.

CONCLUSION

Proteins involved in atherosclerosis, hypercoagulability, and protein misfolding are dysregulated in early-onset preeclampsia and placental dysfunction, which links them and potentially contributes to future maternal cardiovascular disease.

Serum amyloid A, a host-derived DAMP in pregnancy?

Serum amyloid A (SAA) is one of the acute phase proteins released primarily from the liver in response to infection, inflammation and trauma. Emerging evidence indicates that SAA may function as a host-derived damage-associated molecular pattern (DAMP) protein to sense danger signals in pregnancy. The plasma SAA levels in maternal circulation are significantly increased in normal parturition, particularly in postpartum, as well as in gestational disorders such as premature preterm rupture of membranes, pre-eclampsia, gestational diabetes, and recurrent spontaneous abortion. It is likely that SAA acts as a non-specific DAMP molecule in response to inflammation and trauma experienced under these conditions. Notably, SAA can also be synthesized locally in virtually all gestational tissues. Within these gestational tissues, under the induction by bacterial products, pro-inflammatory cytokines and stress hormone glucocorticoids, SAA may exert tissue-specific effects as a toll-like receptor 4 (TLR4)-sensed DAMP molecule. SAA may promote parturition through stimulation of inflammatory reactions via induction of pro-inflammatory cytokines, chemokines, adhesion molecules and prostaglandins in the uterus, fetal membranes and placenta. In the fetal membranes, SAA may also facilitate membrane rupture through induction of matrix metalloproteases (MMPs)- and autophagy-mediated collagen breakdown and attenuation of lysyl oxidase-mediated collagen cross-linking. SAA synthesized in extravillous trophoblasts may promote their invasiveness into the endometrium in placentation. Here, we summarized the current understanding of SAA in pregnancy with an aim to stimulate in-depth investigation of SAA in pregnancy, which may help better understand how inflammation is initiated in gestational tissues in both normal and abnormal pregnancies.

Serum amyloid A, procalcitonin, highly sensitive C reactive protein and tumor necrosis factor alpha levels and acute inflammatory response in patients with hemolysis, elevated liver enzymes, low platelet count (HELLP) and eclampsia

AIM

The aim of this study was to determine the relationship between serum amyloid A (SAA), procalcitonin (ProC), highly sensitive C reactive protein (hsCRP) and tumor necrosis factor (TNF) alpha activity in patients with pre-eclampsia, eclampsia and hemolysis, elevated liver enzymes, low platelet count (HELLP), and the pathogenesis and severity of the disease.

METHOD

Ninety patients at ≥ 32 gestational weeks, according to the last date of menstruation and ultra-sonographic measurements, diagnosed with pre-eclampsia (30 patients), eclampsia (30 patients) or HELLP syndrome (30 patients) were included in the study. Thirty healthy pregnant women from the outpatient clinic during the same period were recruited as the control. The age, gravida, parity, gestational age, systolic and diastolic blood pressures, proteinuria, hemoglobin, thrombocyte count, liver function tests (aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, SAA, TNF alpha, ProC and hsCRP levels during pregnancy) were determined and recorded.

RESULTS

No statistically significant differences were detected between the four groups in terms of age, gravida, parity, gestational age and hemoglobin parameters (P > 0.05). When compared to the control, systolic and diastolic blood pressures, spot and 24 h urine protein levels, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, SAA, ProC, hsCRP and TNF alpha levels were significantly high and thrombocyte levels were low in the pre-eclamptic, eclamptic and HELLP groups (P < 0.05).

CONCLUSION

The investigated parameters were useful to gain an understanding of the maternal inflammatory profile of pre-eclampsia and might be beneficial as markers to predict complications such as HELLP and eclampsia and to provide the necessary preventive approach in these patients.

Maternal serum amyloid A level as a novel marker of primary unexplained recurrent early pregnancy loss

OBJECTIVE

To assess maternal serum amyloid A (SAA) levels among women with primary unexplained recurrent early pregnancy loss (REPL).

METHODS

A prospective study was conducted among women with missed spontaneous abortion in the first trimester at Ain Shams University Maternity Hospital, Cairo, Egypt, between January 21 and December 25, 2014. Women with at least two consecutive primary unexplained REPLs and no previous live births were enrolled. A control group was formed of women with no history of REPL who had at least one previous uneventful pregnancy with no adverse outcomes. Serum samples were collected to measure SAA levels. The main outcome was the association between SAA and primary unexplained REPL.

RESULTS

Each group contained 96 participants. Median SAA level was significantly higher among women with REPL (50.0 μg/mL, interquartile range 26.0-69.0) than among women in the control group (11.6 μg/mL, interquartile range 6.2-15.5; P<0.001). The SAA level was an independent indicator of primary unexplained REPL, after adjusting for maternal age and gestational age (odds ratio 1.12, 95% confidence interval 1.06-1.19; P<0.001).

CONCLUSION

Elevated SAA levels found among women with primary unexplained REPL could represent a novel biomarker for this complication of pregnancy.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.

Association of serum amyloid A with subclinical atherosclerosis in women with gestational diabetes

The aim of our study was to evaluate serum amyloid A (SAA), an acute phase reactant, and carotid intima-media thickness (CIMT) as a valid predictor of atherosclerosis in women with gestational diabetes mellitus (GDM). Serum samples from 39 pregnant women with GDM and 25 healthy pregnant women were collected for the analysis of SAA. CIMT was measured in both groups to evaluate future atherosclerotic heart disease risk. The SAA level was measured with ELISA. The mean arterial blood pressure (MABP), CIMT and SAA levels were significantly higher in women with GDM compared with healthy pregnant controls (p = 0.033, p = 0.001 and p = 0.004, respectively). There were significant correlations between SAA and age, BMI, MABP, 50-g oral glucose tolerance test (OGTT), and A1c (p = 0.048, p = 0.037, p = 0.035, p = 0.042 and p = 0.048, respectively) and between CIMT and BMI, MABP, and 50-g OGTT, (p = 0.001, p = 0.004 and p < 0.001, respectively) in correlation analysis. Furthermore, there was a correlation between SAA and CIMT (p = 0.048). Increased SAA and CIMT values in GDM compared with healthy controls might indicate an increased risk of subclinical atherosclerosis and future atherosclerotic heart disease and the importance of inflammation in this process. These changes were associated with obesity, hypertension and glucose intolerance-related factors (BMI, MABP, and 50-g OGTT), which may be relevant to GDM pathophysiology.

Colchicine-sensitive nephrotic syndrome due to AA amyloidosis

A 28-year-old women is presented who was evaluated for a new-onset postpartum nephrotic syndrome with normal renal function. Histological diagnosis was AA amyloidosis but no underlying disease has been diagnosed despite extensive workup. Complete remission was achieved with colchicine. Upon discontinuation of colchicines, the patient's nephrotic syndrome flared up but completely responded to reinstitution of colchicine therapy. Remission of this patient's nephrotic syndrome is thus not attributable to resolution of any "idiopathic" primary disease.

Plasma biomarkers in a mouse model of preterm labor

Preterm labor (PTL) is frequently associated with inflammation. We hypothesized that biomarkers during pregnancy can identify pregnancies most at risk for development of PTL. An inflammation-induced mouse model of PTL was used. Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry was used to analyze and compare the plasma protein (PP) profile between CD-1 mice injected intrauterine with either lipopolysaccharide (LPS) or PBS on d 14.5 of gestation. The median differences of normalized PP peaks between the two groups were determined using the Mann-Whitney U test and the false discovery rate. In a second series of experiments, both groups of mice were injected with a lower dose of LPS. A total of 1665 peaks were detected. Thirty peaks were highly differentially expressed (p < 0.0001) between the groups. Two 11 kDa protein peaks were identified by MALDI-TOF/TOF-MS and confirmed to be mouse serum amyloid A (SAA) 1 and 2. Plasma SAA2 levels were increased in LPS-treated animals compared with controls and in LPS-treated animals that delivered preterm vs. those that delivered at term. SAA2 has the potential to be a plasma biomarker that can identify pregnancies at risk for development of PTL.