The elevated plasma lipoprotein(a) concentrations in preeclampsia do not precede the development of the disorder

Preliminary study on the role of human defensins, interleukins and PCSK9 in early and late preeclampsia

The lack of reliable methods for preeclampsia (PE) early diagnosis limits the opportunities for timely prevention, diagnosis and treatment. This study aims to identify the alterations of biochemical parameters and the immune system activity to build a panel of markers that can support preeclampsia diagnosis. For this study, we recruited 30 pregnant women: 10 healthy pregnant women (CTR); 10 pregnant women with early preeclampsia (EP); 10 pregnant women with late preeclampsia (LP). We evaluated lipid profile and, by gene expression, we assessed PCSK9, IL-2, IL-6, IL-8, IL-10, TNF-α and TGF-β. Moreover, we evaluated both the serum and gene levels of the defensins HBD-1, HBD-2, HBD-4 and HNP-1. Our results showed an increase in gene expression levels of IL-6 and IL-8 in EP compared to LP (IL-6: median 11.7 vs 3.3, p = 0.005; IL-8: median 634.1 vs 214.1, p = 0.013) and to CTR (IL-6: median 11.7 vs 0.5, p < 0.001; IL-8: median 634.1 vs 225.6, p = 0.012), highlighting a massive activation of immune system in case of more severe preeclampsia. Furthermore, higher serum levels of HBD1 in LP compared to CTR (median: 278.8 vs 67.8, p = 0.005) and to EP (median: 278.8 vs 68.6, p = 0.001) might indicate that the same immune system puts in action protective actions to prevent adverse outcome in these cases. Finally, gene expression levels of PCSK9 decreased significantly in women with EP compared to controls and to LP (median: 0.2 vs 0.9, p = 0.010; median: 0.2 vs 1.2, p = 0.012), causing a decrease in circulating LDL-c necessary for the synthesis of placental hormones.

Lipoprotein (a): impact by ethnicity and environmental and medical conditions

Levels of lipoprotein (a) [Lp(a)], a complex between an LDL-like lipid moiety containing one copy of apoB, and apo(a), a plasminogen-derived carbohydrate-rich hydrophilic protein, are primarily genetically regulated. Although stable intra-individually, Lp(a) levels have a skewed distribution inter-individually and are strongly impacted by a size polymorphism of the LPA gene, resulting in a variable number of kringle IV (KIV) units, a key motif of apo(a). The variation in KIV units is a strong predictor of plasma Lp(a) levels resulting in stable plasma levels across the lifespan. Studies have demonstrated pronounced differences across ethnicities with regard to Lp(a) levels and some of this difference, but not all of it, can be explained by genetic variations across ethnic groups. Increasing evidence suggests that age, sex, and hormonal impact may have a modest modulatory influence on Lp(a) levels. Among clinical conditions, Lp(a) levels are reported to be affected by kidney and liver diseases.

Abnormal Lipid levels as a risk factor of eclampsia, study conducted in tertiary care Hospitals of Khyber Pakhtunkhwa Province - Pakistan

Objective: To evaluate abnormal lipid metabolism as a risk factor of eclampsia in pregnant women.

Methods: This cross sectional study was conducted in three tertiary care hospitals of Peshawar. Serum total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), triglyceride (TG), apolipoprotein A1 (APO-A1), APO-B100, lipoprotein-a (Lpa) were measured in 110 women with eclampsia and compared with 90 healthy pregnant women. Mean lipid levels in cases and controls were compared using student’s t test”.

Results: Mean systolic/diastolic blood pressure, TC, TG, VLDL-C and Lpa levels were significantly higher (p<0.001) in patients compared to control women. Similarly TC: HDL-C, LDL-C: HDL-C and TG: HDL-C ratio in the patients group were significantly higher (p<0.001) and HDL-C: VLDL-C ratio was significantly lower (p<0.001) in the patients as compared to control group. Undesirable cholesterol were noted in 35.8% patients, HDL-C in 50.5%, borderline high concentration of LDL-C in 23.6%, high triglycerides levels in 73.2%, undesirable cholesterol ratio in 52.3% and undesirable LDL-C ratio were noted in 82.1% patients of eclampsia.

Conclusion: Serum lipids were found significantly higher thus early assessment may be helpful in prevention of complications in the eclampsia patients.

The current status of lipoprotein (a) in pregnancy: a literature review

BACKGROUND AND PURPOSE

Lipoprotein (Lp) (a) is a neglected element of the blood lipid profile. It is now recognized as a determinant of coronary heart disease progression and its role in atherosclerosis and its ability to induce thrombosis make it potentially important in the course of normal and complicated pregnancies. Pregnancy involves a major transformation of metabolism to sustain fetal growth. Multiple studies have been conducted on Lp(a) in pregnancy, and it is timely to synthesize and evaluate this evidence.

METHODS AND SUBJECTS

We reviewed the MEDLINE database for all articles published concerning "lipoprotein a" and "pregnancy" from May 2003 to May 2012. A previous comprehensive review assessed the literature up to May 2003.

RESULTS

We critically analyzed 14 studies detailing the effect of complications in pregnancy on Lp(a) profile, and subsequent pregnancy outcomes where available. Studies evaluating the normal metabolic response to pregnancy, pregnancies complicated by pre-eclampsia and intra-uterine growth restriction were reviewed.

CONCLUSIONS

A substantial mass of data has accumulated describing Lp(a) changes in pregnancy. The diversity of study design limits the ability to draw broad-ranging conclusions, but brings into focus the important questions remaining, which we discuss.

Risk factors for cardiovascular disease in women with a history of pregnancy complicated by preeclampsia or intrauterine growth restriction

OBJECTIVE

Women with a history of preeclampsia or intrauterine growth restriction (IUGR) have an increased risk for cardiovascular disease in later life. We determined the presence of traditional and novel risk factors for cardiovascular disease in these women.

METHODS

We studied 256 women with a history of preeclampsia and 59 women with a history of intrauterine growth restriction. Fifty-three women with a history of uncomplicated pregnancy served as controls. We determined values for blood pressure, body mass index, concentrations of cholesterol, high-density lipoprotein cholesterol, triglycerides and lipoprotein (a), and insulin resistance.

RESULTS

Women with a history of preeclampsia exhibited more risk factors for future cardiovascular disease such as dyslipidemia, hypertension, obesity, and increased insulin resistance compared with women with a history of uncomplicated pregnancy. Women with a history of IUGR have higher concentrations of cholesterol and show a tendency to higher BMI, higher triglyceride concentrations, and increased insulin resistance as compared with women with a history of normal pregnancy.

CONCLUSIONS

Preeclampsia or IUGR may represent an early marker for increased risk for early cardiovascular disease.

Lipoprotein (a) in pregnancy: a critical review of the literature

In this article the literature on lipoprotein (a) during normal pregnancy and pregnancy complicated by preeclampsia or intrauterine growth restriction is reviewed. MEDLINE, from January 1966 to May 2003, was searched to locate relevant articles in English. Additional publications were identified by reviewing references in selected articles. Studies were reviewed by predefined and strict criteria. It appeared that methodology and results of studies on lipoprotein (a) during normal and complicated pregnancy were very diverse. Lipoprotein (a) increased with advancing gestation or remained unaltered during normal pregnancy. Women with preeclampsia had higher, unaltered or lower lipoprotein (a) concentrations as compared to normal pregnant controls. Only few studies were in agreement with most of the review criteria. In conclusion, published studies on lipoprotein (a) in pregnancy differ substantially in the used methods to measure lipoprotein (a), sample size, study design and ethnicity of the study population. Therefore, these studies yielded conflicting results and no unequivocal view on the role of lipoprotein (a) in normal and complicated pregnancy. Recommendations for future studies are amongst others: the use of an apo(a) independent method for measuring Lp(a), inclusion of sufficient numbers of patients, the use of a longitudinal study design when the objective is to study the changes of Lp(a) during pregnancy and selection of a study population that is ethnically representative for the general population.

Potential atherogenic roles of lipids, lipoprotein(a) and lipid peroxidation in preeclampsia

AIMS

To evaluate changes in lipid profile, serum levels of malondialdehyde (MDA) and lipoprotein(a) (Lp(a)) and placental MDA in preeclamptic women, and to evaluate the atherogenic role of these changes in the pathophysiology of pre-eclampsia.

METHOD

A cross-sectional study was performed in 20 normal pregnant women, 25 women with mild preeclampsia and 28 women with severe preeclampsia in the third trimester. MDA, which is the endproduct of lipid peroxidation, was measured in placental tissue by the thiobarbituric acid (TBA) method of Ohkawa and colleagues and in serum by the TBA method of Asakawa and Matsushita. Serum lipid levels were measured by with an autoanalyzer, serum apolipoprotein (Apo) A-I and Apo B were measured by nephelometric assay and serum Lp(a) level using a nephelometric agglutination assay method. In preeclamptic and normal pregnant women, multiple comparisons between groups were performed by one-way analysis of variance supplemented with Tukey's HSD post hoc test. The association between placental and serum concentrations among groups was analyzed using the Pearson correlation test.

RESULTS

Serum levels of MDA, Lp(a), total cholesterol, triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and placental MDA were significantly higher, and high-density lipoprotein cholesterol (HDL-C) and Apo A-I levels were significantly lower, in severely preeclamptic and mildly preeclamptic women than in the normal pregnant women, but no difference was observed in Apo B among groups. Serum level of Lp(a) was positively correlated with body mass index in severely preeclamptic women (r=0.489, p=0.008). A significant positive correlation was also found between serum level of MDA and systolic blood pressure in women with severe preeclampsia (r=0.375, p=0.049).

CONCLUSIONS

Our findings suggest that high Lp(a), lipid peroxidation, LDL-C and TG, and low HDL-C and Apo A-I levels, are important risk factors for atherosclerosis among preeclamptic women.

The role of lipoprotein (a) in pregnancies complicated by pre-eclampsia

Endothelial cell dysfunction is a key feature of the pathogenesis of pre-eclampsia. The cause of the endothelial cell injury is probably multifactorial, but poor placenta perfusion plays a major role. In pre-eclampsia, characteristic pathological lesions in the placenta are fibrin deposits, acute atherosis and thrombosis. The similarity between the lesions of pre-eclampsia and atherosclerosis has led to speculations of a common pathophysiological pathway. An abnormal lipid profile is known to be strongly associated with atherosclerotic cardiovascular disease and has a direct effect on endothelial function. Abnormal lipid metabolism seems important in the pathogenesis of pre-eclampsia too. An elevated plasma lipoprotein (a) concentration is a known risk factor for atherosclerotic cardiovascular disease. In this paper, we discuss three hypotheses about the mechanisms by which lipoprotein (a) may be associated with pre-eclampsia: 1. Lp(a), as an acute-phase reactant, transporting cholesterol to sites of endothelial damage for reparation, temporarily increases during pregnancy and increases more during a pregnancy complicated by mild to moderate pre-eclampsia as compared to an uncomplicated pregnancy, in response to a greater extend of endothelial injury in pre-eclampsia. After delivery, pre-eclampsia subsides and Lp(a) concentrations return to baseline levels. 2. In cases of severe pre-eclampsia, there is even more extensive endothelial damage and consequently a higher consumption of Lp(a) in reparation of this vascular damage. These women will have lower concentrations of Lp(a). 3. High baseline concentrations of Lp(a), which are genetically determined, may induce or contribute to the development of pre-eclampsia by promoting endothelial dysfunction. In this line of reasoning one would expect to find higher concentrations of Lp(a) in women at risk for developing pre-eclampsia in a future pregnancy or with a history of pre-eclampsia. As discussed above, these women are also at increased risk for future cardiovascular disease as compared to women with a history of normal pregnancy. The pathophysiologic changes associated with cardiovascular disease may also be responsible for the increased incidence of pre-eclampsia in these women.