Lipoprotein lipase and apoE polymorphisms: relationship to hypertriglyceridemia during pregnancy

Impact of acute pancreatitis during pregnancy in Chinese women: a meta-analysis

A random-effects meta-analysis was performed in English and Chinese databases since its inception to August 2020 to assess the incidence, causes and severity of acute pancreatitis (AP) at various stages of pregnancy, maternal and foetal mortality. A total of 154 articles representing 4034 patients with AP during pregnancy in China were included for the analysis. The incidence of AP during pregnancy was 0.0469 (95% confidence interval [CI], 0.0349; 0.0627) in the first trimester, whereas it was 0.2518 (95% CI, 0.2210; 0.2854) and 0.6323 (95% CI, 0.5870; 0.6753) in the second and third trimester, respectively. The major causes of AP were hypertriglyceridaemia (0.351 [95% CI, 0.3202; 0.3834]) and biliary pancreatitis (0.424 [95% CI, 0.4094; 0.5002]). The severity of AP was mild in majority of the patients. The incidence of AP at maternal mortality was 0.0184 (95% CI, 0.0126; 0.0269) and foetal mortality was 0.1018 (95% CI, 0.0867; 0.1192). Our meta-analysis revealed that hypertriglyceridaemia and biliary pancreatitis remain the major causes of AP during pregnancy. Foetal mortality requires further investigation. IMPACT STATEMENTWhat is already known on this subject? Acute pancreatitis (AP) in pregnant women is characterised by acute onset and delay in understanding the interaction of the metabolic changes with pancreatic pathophysiology, and thus becomes difficult to diagnose the disease and provide timely treatment to the patients. This poses a greater health risk among women and their foetus by increasing their chances of mortality.What the results of this study add? We performed an exhaustive, random-effects meta-analysis involving 154 articles representing 4034 patients to assess the incidence of AP at various stages of pregnancy, the causes of AP and the severity of AP during pregnancy, maternal and foetal mortality.What are the implications of these findings for clinical practice and/or further research? Our meta-analysis revealed that hypertriglyceridaemia and biliary pancreatitis remain the major causes of AP during pregnancy. Although the rates of maternal mortality have decreased in the recent years, foetal mortality still remains high and requires further investigation.

Identification of genes associated with susceptibility to persistent breeding-induced endometritis by RNA-sequencing of uterine cytobrush samples

This study aimed to investigate the susceptibility to persistent breeding-induced endometritis (PBIE). Cytobrush samples were collected from 81 broodmares 1-3 days before artificial insemination (AI). Susceptibility to PBIE was evaluated by the presence of ≥ 2 cm of intrauterine fluid 24 h after AI, besides the fertility was determined by a sonographic pregnancy diagnosis 2 weeks after ovulation. RNA expressions were compared between susceptible non-pregnant (SNP) mares (n=9) and resistant pregnant (RP) mares (n=9) as well as between susceptible pregnant (SP) mares (n=9) and susceptible non-pregnant (SNP) mares. 66 differentially expressed genes (DEGs) were identified between SNP and RP mares and 60 DEGs between SP and SNP mares. In SNP compared to RP mares, transcript levels of genes regulating steroid hormone metabolism and neutrophil chemotaxis were lower, while higher for genes participating in uterine inflammation.Transcripts of genes related to extracellular matrix degradation, tissue adhesions, and fibrosis were lower in SP mares than in SNP mares, while higher for genes related to uterine cell proliferation, differentiation, and angiogenesis in SP mares than SNP mares. In conclusion, increased transcript levels of apolipoprotein E (APOE) and roundabout 2 (ROBO2), cluster domain 44 (CD44), integrin beta 3 (ITGB3), and epidermal growth factor (EGF) are possible biomarkers for susceptibility to PBIE. While higher expression of fibroblast growth factor 9 (FGF9), kinase domain receptor (KDR), and C-X-C motif chemokine ligand (CXCL) 16, collagen type V alpha 2 (COL5A2) and fibronectin (FN1) are suggested indicators of fertility in susceptible mares if they receive proper breeding management.

Current Diagnosis and Management of Primary Chylomicronemia

Primary chylomicronemia (PCM) is a rare and intractable disease characterized by marked accumulation of chylomicrons in plasma. The levels of plasma triglycerides (TGs) typically range from 1,000 - 15,000 mg/dL or higher.

PCM is caused by defects in the lipoprotein lipase (LPL) pathway due to genetic mutations, autoantibodies, or unidentified causes. The monogenic type is typically inherited as an autosomal recessive trait with loss-of-function mutations in LPL pathway genes ( LPL , LMF1 , GPIHBP1 , APOC2 , and APOA5 ). Secondary/environmental factors (diabetes, alcohol intake, pregnancy, etc.) often exacerbate hypertriglyceridemia (HTG).

The signs, symptoms, and complications of chylomicronemia include eruptive xanthomas, lipemia retinalis, hepatosplenomegaly, and acute pancreatitis with onset as early as in infancy. Acute pancreatitis can be fatal and recurrent episodes of abdominal pain may lead to dietary fat intolerance and failure to thrive.

The main goal of treatment is to prevent acute pancreatitis by reducing plasma TG levels to at least less than 500-1,000 mg/dL. However, current TG-lowering medications are generally ineffective for PCM. The only other treatment options are modulation of secondary/environmental factors. Most patients need strict dietary fat restriction, which is often difficult to maintain and likely affects their quality of life.

Timely diagnosis is critical for the best prognosis with currently available management, but PCM is often misdiagnosed and undertreated. The aim of this review is firstly to summarize the pathogenesis, signs, symptoms, diagnosis, and management of PCM, and secondly to propose simple diagnostic criteria that can be readily translated into general clinical practice to improve the diagnostic rate of PCM. In fact, these criteria are currently used to define eligibility to receive social support from the Japanese government for PCM as a rare and intractable disease.

Nevertheless, further research to unravel the molecular pathogenesis and develop effective therapeutic modalities is warranted. Nationwide registry research on PCM is currently ongoing in Japan with the aim of better understanding the disease burden as well as the unmet needs of this life-threatening disease with poor therapeutic options.

Hypertriglyceridemia and adverse outcomes during pregnancy

Introducción. Durante el embarazo, los niveles séricos de triglicéridos maternos aumentan como un mecanismo de adaptación fisiológica para suplir las necesidades del feto en desarrollo. Pese a que el incremento excesivo se ha asociado a preeclampsia, macrosomía y parto pretérmino, no se han establecido de manera contundente los niveles a partir de los cuales se deben tomar medidas en cada trimestre para prevenir complicaciones.Objetivo. Hacer una revisión sobre fisiopatología, efectos en madre e hijo, valores esperados en cada trimestre e intervenciones terapéuticas en hipertrigliceridemia gestacional.Materiales y métodos. Se realizó una revisión con la búsqueda de artículos en las bases de datos ScienceDirect, PubMed, Scopus, LILACS, Cochrane y SciELO con los términos: Pregnancy; Hypertriglyceridemia; Maternal-Fetal Exchange; Fetal Development; Pregnancy Complications y sus equivalentes en español.Resultados. Se encontraron 59 artículos que cumplieron los criterios de búsqueda y daban respuesta a los objetivos.Conclusiones. El número limitado y la gran variabilidad de los datos indican la necesidad de realizar más investigaciones que establezcan los rangos de normalidad de los triglicéridos durante los tres trimestres del embarazo y así determinar riesgos e intervenciones eficaces antes de la gestación y reducir la morbimortalidad materno-infantil.

Clinical and genetic features of 3 patients with familial chylomicronemia due to mutations in GPIHBP1 gene

BACKGROUND

Familial chylomicronemia is a recessive disorder that may be due to mutations in lipoprotein lipase (LPL) and in other proteins such as apolipoprotein C-II and apolipoprotein A-V (activators of LPL), GPIHBP1 (the molecular platform required for LPL activity on endothelial surface), and LMF1 (a factor required for intracellular formation of active LPL).

METHODS

We sequenced the familial chylomicronemia candidate genes in 2 adult females presenting long-standing hypertriglyceridemia and a history of acute pancreatitis.

RESULTS

Both probands had plasma triglyceride >10 mmol/L but no mutations in the LPL gene. The sequence of the other candidate genes showed that one patient was homozygous for a novel missense mutation p.(Cys83Arg), and the other was homozygous for a previously reported nonsense mutation p.(Cys 89*), respectively, in GPIHBP1. Family screening showed that the hypertriglyceridemic brother of the p.(Cys83Arg) homozygote was also homozygous for this mutation. He had no history of pancreatitis. The p.(Cys83Arg) heterozygous carriers had normal triglyceride levels. The substitution of a cysteine residue in the Ly6 domain of GPIHBP1 is predicted to abolish one of the disulfide bridges required to maintain the structure of GPIHBP1. The p.(Cys89*) mutation results in a truncated protein devoid of function.

CONCLUSIONS

Both mutant GPIHBP1 proteins are expected to be incapable of transferring LPL from the subendothelial space to the endothelial surface.

Genetic Variants Associated with Gestational Hypertriglyceridemia and Pancreatitis

Severe hypertriglyceridemia is a well-known cause of pancreatitis. Usually, there is a moderate increase in plasma triglyceride level during pregnancy. Additionally, certain pre-existing genetic traits may render a pregnant woman susceptible to development of severe hypertriglyceridemia and pancreatitis, especially in the third trimester. To elucidate the underlying mechanism of gestational hypertriglyceridemic pancreatitis, we undertook DNA mutation analysis of the lipoprotein lipase (LPL), apolipoprotein C2 (APOC2), apolipoprotein A5 (APOA5), lipase maturation factor 1 (LMF1), and glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1) genes in five unrelated pregnant Chinese women with severe hypertriglyceridemia and pancreatitis. DNA sequencing showed that three out of five patients had the same homozygous variation, p.G185C, in APOA5 gene. One patient had a compound heterozygous mutation, p.A98T and p.L279V, in LPL gene. Another patient had a compound heterozygous mutation, p.A98T & p.C14F in LPL and GPIHBP1 gene, respectively. No mutations were seen in APOC2 or LMF1 genes. All patients were diagnosed with partial LPL deficiency in non-pregnant state. As revealed in our study, genetic variants appear to play an important role in the development of severe gestational hypertriglyceridemia, and, p.G185C mutation in APOA5 gene appears to be the most common variant implicated in the Chinese population. Antenatal screening for mutations in susceptible women, combined with subsequent interventions may be invaluable in the prevention of potentially life threatening gestational hypertriglyceridemia-induced pancreatitis.

Newborn APOE genotype influences maternal lipid profile and the severity of high-risk pregnancy - preeclampsia: Interaction with maternal genotypes as a modulating risk factor in preeclampsia

AIM

To establish the role of the interaction between maternal and newborn apolipoprotein E (APOE) genotypes on the risk, lipid profile and prognosis of preeclampsia (PE).

MATERIALS AND METHODS

Forty-seven preeclamptic women and 94 normotensive pregnant women and their newborns were genotyped for APOE using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis.

RESULTS

Maternal APOE-ε4 allele was associated with an about eight times higher risk of PE (adjusted OR = 8.4, 95% CI: 2.51-28.17, p = 0.001). The multivariate logistic regression model showed that the newborn APOE-ε4 allele was associated with an about six times higher risk of PE (adjusted OR = 5.6, 95% CI: 2.09-15.21, p = 0.001) for the given gestational age levels. Pregnant women with severe PE whose newborns carried the APOE-ε4 allele delivered at earlier gestational ages neonates with a lower birth weight compared to pregnant women with newborns negative for this allele. Higher TG and LDL-C levels and lower HDL-C levels were found in pregnant women with severe PE whose newborns were carriers of the APOE-ε4 allele compared to preeclamptic women whose newborns were carriers of the ε3/ε3 genotype. If we checked the combined effect of the mother/newborn genotypes on the risk of PE, we found that the risk to develop PE was 15.4-fold (p < 0.001) increased if mothers or newborns were carriers of the APOE-ε4 allele. The risk increased to 20.02 (p < 0.001) if both the mother and newborn were carriers of the APOE-ε4 allele.

CONCLUSIONS

Our study confirms the maternal/newborn APOE genotype interaction influences the risk for PE, as well as prognosis and lipid profile.

The -93T/G LPL Promoter Polymorphism Is Associated With Lower Third-Trimester Triglycerides in Pregnant African American Women

BACKGROUND

Hypertriglyceridemia is a risk factor for cardiovascular disease and several pregnancy complications. Lipoprotein lipase (LPL) genetic variation modulates nonpregnancy plasma triglycerides, but its effects during pregnancy are unknown. The G allele of the LPL -93T/G promoter polymorphism is 16-23 times more prevalent in Blacks than in Whites, contributing to lower triglycerides in nonpregnant African Americans by increasing LPL expression.

PURPOSE

This study investigated whether the triglyceride-lowering effect of -93G is observed in African Americans during pregnancy.

METHODS

Genotyping was performed on 124 African American women with uncomplicated pregnancies for common functional LPL polymorphisms/mutations (-93T/G, D9N, N291S, and S447X). Third-trimester plasma triglyceride, high- and low-density lipoprotein cholesterol, apolipoprotein B, and free fatty acid concentrations were measured with colorimetric assays. Clinical characteristics and lipid values were compared across the -93T/G genotypes.

RESULTS

Triglycerides were significantly lower in women with the -93GG compared to the -93TT genotype, both with (n = 124, p = .02) and without (n = 108, p = .03) inclusion of participants with other LPL variant alleles. Triglyceride differences persisted after adjustment for prepregnancy body mass index, gestational age at delivery, and smoking. There were no significant differences in the other lipids or apolipoprotein B by -93T/G genotype.

CONCLUSIONS

Despite the considerable metabolic changes accompanying pregnancy, the triglyceride-lowering effect associated with the -93GG LPL genotype in African Americans persists during late pregnancy. The -93GG genotype might protect against pregnancy complications stemming from hypertriglyceridemia, but the overall increased risk of pregnancy complications in African American women points to complex, multifactorial relationships among risk factors, race, and adverse pregnancy outcomes.

Low abundance plasma proteins in labour

Every year, millions of births worldwide are complicated by prematurity or difficult post-term deliveries, resulting in a high incidence of perinatal mortality and morbidity. Our poor understanding of human parturition is a key reason for our inability to improve the management of preterm and post-term birth. In this study, we used proteomic techniques to look into protein changes in placental blood plasma obtained from women before or after spontaneous or induced labour, with vaginal or caesarean section deliveries. Our aim was to understand the basic mechanisms of human parturition regardless of whether the signals that trigger labour are of maternal and/or fetal origin. We found proteins from 33 genes with significantly altered expression profiles in relation to mode of labour and delivery. Most changes in labour occurred in proteins associated with ‘immune and defence responses’. Although the signal transduction and regulation of these pathways varied among modes of delivery, hepatocyte nuclear factor 1 homeobox A emerged as a shared protein in the mechanism of labour. Moreover, several apolipoproteins such as apolipoprotein A-IV and APOE were found to change with labour, and these changes were also confirmed in maternal plasma. This study has identified significant protein changes in placental intervillous plasma with labour and has revealed several pathways related to human parturition.

Apolipoprotein E polymorphisms and spontaneous pregnancy loss in patients with endometriosis

Endometriosis affects >10% of women during their reproductive years, many of whom report high rates of spontaneous pregnancy loss (SPL). We examined whether gene polymorphisms in apolipoprotein E (APOE), which is involved in lipoprotein metabolism, are associated with endometriosis and/or endometriosis-associated infertility. We conducted a cross-sectional genetic association study of women surgically confirmed to have endometriosis (n = 345) and no surgical evidence of the disease (n = 266). Genotyping of APOE polymorphism (ε2, ε3, ε4) was conducted by polymerase chain reaction-restriction fragment length polymorphism followed by visualization of specific patterns by gel electrophoresis. Statistical significance of differences in genotype and allelic frequencies was assessed using Pearson's χ(2) test and Risk analysis. Overall, we found no association between APOE genotype and diagnosis of endometriosis. However, patients with endometriosis who reported at least one SPL were three times more likely to be ε2 carriers and 2-fold less likely to be ε4 carriers. Compared with ε3 carriers, patients with endometriosis who were ε2 carriers and had at least one live birth reported four times the rate of SPL, while ε4 carriers were <0.4-fold less likely to report an SPL. Our data suggest that there may be an association between APOE allelic frequency and SPL in patients with endometriosis, which appears to be independent of mechanisms associated with infertility, an intriguing observation that deserves further investigation.

Acute pancreatitis in pregnancy: an overview

Acute pancreatitis is rare in pregnancy but it is associated with increased incidence of maternal and fetal mortality. It should be considered in the differential diagnosis of upper quadrant abdominal pain with or without nausea and vomiting. The commonest identified causes of acute pancreatitis in pregnancy are gallstones, alcohol and hypertriglyceridemia. The main laboratory finding is increased amylase activity. Appropriate investigations include ultrasound of the right upper quadrant and measurement of serum triglycerides and ionized calcium. Management of gallstone pancreatitis is controversial, although laparoscopic cholecystectomy and endoscopic retrograde cholangiopancreatography (ERCP) are often used and may be associated with lower complication rates. In hypertriglyceridemia-induced acute pancreatitis ω-3 fatty acids and even therapeutic plasma exchange can be used. We also discuss preventive measures.

The use of plasma lipid and lipoprotein ratios in interpreting the hyperlipidaemia of pregnancy

The aim of this study was to determine the lipid and lipoproteins ratio in pregnant mothers and to evaluate their role in the interpretation of hyperlipidaemias. A total of 222 pregnant women who registered for ANC and 222 non-pregnant healthy women of the sameage and parity as control were recruited for the study. A sample of venous blood after an overnight fast was collected for analysis and interpretation. The mean ± SD age (years) of pregnant women, 27.317 ± 7.283 years and that of the non-pregnant women, 26.234 ± 6.234 years are not significantly different, p = 0.429. Total cholesterol, HDL-c and TGs were significantly higher in pregnant women (5.29 ± 1.04 mmol/l, 1.64 ± 0.42 mmol/l and 1.74 ± 0.42 mmol/l) compared with that of non-pregnant women (4.64 ± 0.92 mmol/l, 1.25 ± 0.35 mmol/l and 1.37 ± 0.45 mmol/l, respectively) All showed p < 0.000. The frequencies of hypercholesterolaemia, 96(43.2%) and hypertriglyceridaemia, 82 (36.9%), are significantly higher in the pregnant women than in the non-pregnant women, 58 (26.1%) and 26 (11.7%), respectively. TC/HDL-C ratio, 3.33 ± 1.01 and LDL/HDL-C ratio, 1.91 ± 0.85 are significantly lower in pregnant women compared with non-pregnant women counterparts, 3.89 ± 0.97 and 2.35 ± 0.84, respectively. Similarly the frequencies of increased TC/HDL-C ratio, 22 (9.9%) and LDL/HDL-C ratio, 16 (7.2%) are significantly less in the pregnant compared with the non-pregnant women, 54 (24.3%) and 28 (12.6%), respectively.

A prospective case-control study analyzes 12 thrombophilic gene mutations in Turkish couples with recurrent pregnancy loss

PROBLEM

Recurrent pregnancy loss (RPL) is a heterogeneous disorder. The contribution of specific thrombophilic genes to the pathophysiology of RPL has remained controversial. We evaluated the prevalences of 12 thrombophilic gene mutations among homogenous Caucasian couples with RPL and fertiles.

METHOD

of study This was a prospective case-control study evaluating 272 women with RPL and 152 of their male partners, and a control group of 56 fertile couples. We investigated mutations including FV Leiden, factor V H1299R, factor II prothrombin G20210A, F XIII V34L, beta-fibrinogen -455G>A, plasminogen activator inhibitor-1, GPIIIa L33P (HPA-1 a/b L33P), MTHFR C677T, MTHFR A1298C, ACE I/D, Apo B R3500Q, and Apo E.

RESULTS

Overall, heterozygous mutations of FV Leiden, FXIII V34L, GPIIIa L33P, Apo E4, and prothrombin G20210A and homozygous mutations of PAI-1and MTHFR C677T were associated with RPL. There was no meaningful association between RPL and other studied genes.

CONCLUSION

In contrast to the other mutations and polymorphisms, FV Leiden, FXIII V34L, GPIIIa L33P, Apo E, prothrombin G20210A, PAI-1 and MTHFR C677T gene mutations may help to identify the couples at risk for recurrent pregnancy loss.

Pregnancy-induced hyperlipoproteinemia: review of the literature

It is well known that with the effect of hormonal changes during pregnancy, plasma lipid levels increase. Expected elevations for triglyceride and cholesterol levels during a normal gestational period usually do not exceed 332 mg/dL and 337 mg/dL, respectively (corresponding 95th percentile values). However, elevations over the 95th percentile values can be observed during pregnancy, and patients with levels over these expected adaptation levels can be divided into 2 groups: (1) supraphysiologic hyperlipoproteinemia during pregnancy and (2) extreme hyperlipoproteinemia limited to gestational period (triglyceride level >1000 mg/dL). Regarding the first group, some of these patients may develop hyperlipoproteinemia in their future life. What percentage of these women will translate into hyperlipoproteinemia later in life and how efficiently these women can be screened during pregnancy is an enigma. The underlying disorders in the second group of patients at least include dysbetalipoproteinemia, partial lipoprotein lipase deficiency, and apoprotein E3/3 genotype. Pregnancy had been reported to induce severe hyperlipoproteinemia that is limited to gestational period in these disorders. Dysbetalipoproteinemia, partial lipoprotein lipase deficiency, and apoprotein E3/3 genotype probably bring risks and implications to the future life of the carrying individuals although the true extent of the risks is yet to be defined. When disorders unique to gestational period such as gestational diabetes are considered, pregnancy may be accepted as an opportunity to identify women under risk of cardiovascular morbidity and mortality.

The association of Apoprotein E polymorphisms with recurrent pregnancy loss

PROBLEM

We have previously reported the role of polymorphisms of thrombogenic genes involved in coagulation and fibrinolysis as risk factors for recurrent pregnancy loss. Thrombophilia has been viewed as a multigenic disorder rather than a monogenetic clinical phenotype and Apo E has been shown to play an important role in lipid metabolism in pregnancy. As individuals carrying the E4 allele of the ApoE gene have the highest risk for thrombosis, we evaluated the frequency of the Apo E4 genotype among women suffering from recurrent pregnancy loss.

METHOD OF STUDY

Buccal swabs were obtained from 69 women with a history of two or more consecutive spontaneous abortions and 37 women with at least two live births and not more than one miscarriage. DNA was extracted from the buccal swabs and PCR amplification of Apo E2, E3, and E4 was performed.

RESULTS

Women experiencing recurrent pregnancy loss had a significantly higher prevalence of Apo E3/4, E4/4 genotypes (21.7%) compared with control women (5.4%) (P = 0.036).

CONCLUSION

Apo E4 polymorphism may contribute to the thrombophilic risk factors contributing to recurrent pregnancy loss.

Lipoprotein lipase PvuII polymorphism is associated with variations in serum lipid levels in non-diabetic pregnant women

The aim of the present study was to determine if there is an association between the single nucleotide polymorphisms (SNPs) of the lipoprotein lipase (LPL) and apolipoprotein E (apo E) genes and the serum lipid profile in pregnancy and puerperium. Non-diabetic women of European descent in the third semester of pregnancy (N = 120) were selected. Those with diseases or other condition that could modify their lipid profile were excluded from the study (N = 32). Serum lipids were measured by routine laboratory procedures and genomic DNA was extracted by a salting out method. LPL (PvuII and HindIII) and apo E (HhaI) SNPs were detected by the polymerase chain reaction and restriction fragment length polymorphism. Categorical and continuous variables were compared by the chi-square test and Student t-test or ANOVA, respectively. Women carrying the LPL P1P1 genotype had higher serum LDL cholesterol (N = 21; 155 +/- 45 mg/dL) than women carrying the P1P2/P2P2 genotypes (N = 67; 133 +/- 45 mg/dL; P = 0.032). During the puerperium period, serum levels of triglycerides and VLDL cholesterol were significantly reduced in women carrying the P1P1 (73%, P = 0.006) and P1P2 (51%, P = 0.002) genotypes but not in women carrying the P2P2 genotype (23%, P > 0.05). On the other hand, serum concentrations of lipids did not differ between the LPL HindIII and apo E genotypes during pregnancy and after delivery. We conclude that LPL PvuII SNP is associated with variations in serum lipids during pregnancy and the puerperal period in non-diabetic women.

Antioxidant activity and lipid peroxidation in preeclampsia

BACKGROUND

Epidemiologic studies demonstrate a relation between preeclampsia and an increased risk of future maternal coronary heart disease. The pathophysiology of the underlying mechanism is unknown. Disorders of lipoprotein metabolism may contribute to endothelial dysfunction. Oxidative stress and decreased antioxidant defense enhances free radical-mediated membrane lipid peroxidation and possibly vascular endothelial damage. The aim of this study was to elucidate the possible relation between lipidemic status, lipid peroxidation and albumin with total antioxidant activity (AOA) that may contribute to atherogenicity in preeclamptic women.

METHODS

Twenty-five women with preeclampsia and 25 normal pregnant women who were matched for maternal and gestational age were selected for the study. Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), atherogenic index (AI), malondialdehyde (MDA), a marker of lipid peroxidation, AOA and albumin levels were measured.

RESULTS

MDA, TC and AI were significantly elevated (p < 0.001), and HDL-C, AOA and albumin levels were significantly decreased (p < 0.001) in preeclamptic patients compared to the control group.

CONCLUSION

We conclude that hypercholesterolemia leads to excessive lipid peroxidation. Coexistent diminution in antioxidant activity leads to an imbalance between prooxidants and antioxidants, resulting in oxidative stress. Oxidative stress and elevated AI may contribute to atherogenicity in preeclampsia.

Maternal and cord serum lipid profiles of preterm infants with respiratory distress syndrome

BACKGROUND

Lipid metabolism has an important role in fetal development during the late stage of gestation, including growth and fat accretion in utero, increasing amniotic fluid lecithin levels with maturation of pulmonary function and changes in the levels of minor phospholipids in amniotic fluid.

OBJECTIVE

The aim of this study was to compare the maternal and cord lipid profiles of preterm infants with respiratory distress syndrome (RDS) and a control group without RDS.

METHOD

The study groups consisted of 166 preterm infants with gestational ages ranging from 25 to 36 weeks, and birth weights ranging from 748 to 2495 g. Of these infants, 57 developed RDS and 109 infants served as controls. The infants were divided into four gestational age groups (34 to 36, 31 to 33, 28 to 30 and 25 to 27 weeks). Stepwise linear regression analyses were performed to determine independent contribution of each lipid parameter of the infants to their characteristics and mothers' variables.

RESULT

Total cholesterol, high-density and low-density lipoproteins (LDL) cholesterols levels were lower in infants with RDS and in their mothers than in controls, and maternal lipid profile was related to those of their infants (P<0.05). Pregravid body mass index (BMI) was related to triglyceride levels of the infants, and weight gain during pregnancy was related to LDL cholesterol levels of the infants (P<0.05).

CONCLUSION

RDS is accompanied with lipid alteration in infants and their mothers. Pregravid BMI and weight gain during pregnancy might have a prognostic significance in the prediction of respiratory distress in early neonatal period.

A systematic review and meta-analysis of the relationship between lipoprotein lipase Asn291Ser variant and diseases

This systematic review attempted to summarize the associations between the Asn291Ser variant in the lipoprotein lipase (LPL) gene and dyslipidemia, the risk of type 2 diabetes mellitus (T2DM), and coronary heart disease (CHD). In addition, the relationships between the Asn291Ser variant and other metabolic diseases such as obesity and high blood pressure were also investigated in this systematic review. We systematically reviewed the literature by means of a meta-analysis. Twenty-one articles, including 19,246 white subjects, were selected for this meta-analysis. The summary standardized mean difference (SMD) of plasma triglyceride (TG) for carriers compared with noncarriers of the Asn291Ser variant was 3.23 (P < 0.00001). The summary SMD of plasma HDL-cholsterol (HDL-C) for carriers compared with noncarriers of the Asn291Ser variant was -3.42 (P < 0.0001). The summary SMD of the association of the Asn291Ser variant with plasma TG increased with increasing age and weight gain. Significant interactions between the LPL Asn291Ser variant and fasting glucose, T2DM, and CHD were seen (P = 0.02, 0.04, and 0.01, respectively). No significant interactions were seen between the LPL Asn291Ser variant and body mass index, waist-hip ratio, and blood pressure (P > 0.05). This meta-analysis indicates that the Asn291Ser variant in the LPL gene is a risk factor for dyslipidemia, characterized by hypertriglyceridemia and low HDL-C levels. And the Asn291Ser variant in the LPL gene predisposes to more severe dyslipidemia with increasing age and weight gain. Also, this meta-analysis shows that the LPL Asn291Ser variant is associated with CHD and T2DM.

Functional variants of the lipoprotein lipase gene and the risk of preeclampsia among non-Hispanic Caucasian women

Hypertriglyceridemia is an important pathophysiologic feature of preeclampsia, a common vascular disorder of pregnancy. Three well-documented functional variants (N291S, S447X, and D9N) of the lipoprotein lipase gene were related to hypertriglyceridemia. Results from the only two studies concerning the relationship between these variants and preeclampsia risk have been inconsistent. We investigated this relationship in a case-control study including 144 preeclamptic and 290 normotensive pregnant women (all non-Hispanic Caucasians). We estimated odds ratios (OR) and 95% confidence intervals (CI) adjusted for maternal age, pre-pregnancy body mass index, and parity. After adjusting for covariates, women with the 291 N/S or S/S genotype had significantly increased risk of preeclampsia (OR 6.9, 95% CI 1.9-25.4) compared with women with the common 291N/N genotype. The 447 S/X or X/X genotype was not significantly associated with preeclampsia risk. The frequency of the 9N variant allele was 1.8% in controls, while this allele was not observed among cases. Haplotype 9D/291S/447S was strongly associated with higher risk of preeclampsia as compared with the most common haplotype 9D/291N/447S (adjusted OR 6.6, 95% CI 1.7-25.0). Results from our study support the thesis that abnormal lipid metabolism is important in the pathogenesis of preeclampsia.

Nutrigenomics and nutrigenetics: the emerging faces of nutrition

The recognition that nutrients have the ability to interact and modulate molecular mechanisms underlying an organism's physiological functions has prompted a revolution in the field of nutrition. Performing population-scaled epidemiological studies in the absence of genetic knowledge may result in erroneous scientific conclusions and misinformed nutritional recommendations. To circumvent such issues and more comprehensively probe the relationship between genes and diet, the field of nutrition has begun to capitalize on both the technologies and supporting analytical software brought forth in the post-genomic era. The creation of nutrigenomics and nutrigenetics, two fields with distinct approaches to elucidate the interaction between diet and genes but with a common ultimate goal to optimize health through the personalization of diet, provide powerful approaches to unravel the complex relationship between nutritional molecules, genetic polymorphisms, and the biological system as a whole. Reluctance to embrace these new fields exists primarily due to the fear that producing overwhelming quantities of biological data within the confines of a single study will submerge the original query; however, the current review aims to position nutrigenomics and nutrigenetics as the emerging faces of nutrition that, when considered with more classical approaches, will provide the necessary stepping stones to achieve the ambitious goal of optimizing an individual's health via nutritional intervention.

Do long-term HDL-C declines associated with a first birth vary by apo E phenotype? The Coronary Artery Risk Development in Young Adults (CARDIA) study

BACKGROUND

High-density lipoprotein cholesterol (HDL-C) levels in premenopausal and postmenopausal women are differentially affected by exogenous sex hormones depending on their apolipoprotein E (apo E) genotype. Because endogenous sex hormones markedly increase during pregnancy, we examined whether HDL-C declines after a first birth varied by apo E polymorphisms.

METHODS

In 1147 nulliparas (416 black, 731 white), fasting blood samples (nonpregnant) were drawn at baseline and at follow-up years 5, 7, and 10. Time-dependent pregnancy groups included 0 pregnancies (P0), 1+ short pregnancy (P1+), 1 birth (B1), 2 or more births (B2+). ApoE groups by alleles identified with a phenotype method included E4 (4/3 and 4/4), E3 (3/3), and E2 (2/2 and 3/2). Differences in adjusted mean HDL-C changes among pregnancy groups and ApoE groups were examined using repeated measures multiple linear regression.

RESULTS

HDL-C declines associated with parity (one or more births) depended on ApoE group (ApoE*Pregnancy Interaction; p < 0.002). For B1 and B2+ vs. P0, HDL-C declines were -2.4 to -2.7 mg/dl in E4 and -3.4 to -4.1 mg/dl in E3. In E2, HDL-C declines were -6.6 mg/dl for one birth, and -11.5 mg/dl for two or more births, each relative to the 0 pregnancies (P0) group (linear trend, p < 0.001).

CONCLUSIONS

The degree to which childbearing adversely affects long-term HDL-C declines varies by apo E phenotype, based on a method that accurately classifies genotype. Our findings show that 2/2 and 3/2 genotypes are associated with larger parity-related HDL-C declines than 3/3, 4/3, and 4/4 genotypes.

Lipoprotein metabolism of pregnant women is associated with both their genetic polymorphisms and those of their newborn children

To explore whether the placenta contributes to the lipoprotein metabolism of pregnant women, we took advantage of the fact that placental proteins are encoded from the fetal genome and examined the associations between lipids of 525 pregnant women and the presence, in their newborns, of genetic polymorphisms of LPL and apolipoprotein E (APOE), two genes expressed in placenta. After adjustment for maternal polymorphisms, newborn LPL*S447X was associated with lower triglycerides (-21 +/- 9 mg/dl), lower LDL-cholesterol (LDL-C; -12 +/- 5 mg/dl), lower apoB (-14 +/- 4 mg/dl), higher HDL-C (5 +/- 2 mg/dl), and higher apoA-I (9 +/- 4 mg/dl) in their mothers; newborn LPL*N291S was associated with higher maternal triglycerides (114 +/- 31 mg/dl); and newborn APOE*E2 (compared to E3E3) was associated with higher maternal LDL-C (14 +/- 6 mg/dl) and higher maternal apoB (14 +/- 5 mg/dl). These associations (all P < 0.05) were independent of polymorphisms carried by the mothers and of lipid concentrations in newborns and were similar in amplitude to the associations between maternal polymorphisms and maternal lipids. Such findings support the active role of placental LPL and APOE in the metabolism of maternal lipoproteins and suggest that fetal genes may modulate the risk for problems related to maternal dyslipidemia (preeclampsia, pancreatitis, and future cardiovascular disease).

Complete Rescue of Lipoprotein Lipase–Deficient Mice by Somatic Gene Transfer of the Naturally Occurring LPL S447X Beneficial Mutation

The naturally occurring human lipoprotein lipase S447X variant (LPL S447X ) exemplifies a gain-of function mutation with significant benefits including decreased plasma triglycerides (TG), increased high-density lipoprotein (HDL) cholesterol, and reduced risk of coronary artery disease. The S447X variant may be associated with higher LPL catalytic activity; however, in vitro data supporting this hypothesis are contradictory. We wanted to investigate the in vivo mechanism by which the LPL S447X variant improves the lipid profile of S447X carriers. We conducted a functional assessment of human LPL S447X compared with LPL WT in mice. LPL variants were compared in the absence of endogenous mouse LPL in newborn LPL −/− mice by adenoviral-mediated gene transfer. LPL −/− mice normally exhibit severe hypertriglyceridemia and die within 48 hours of birth. LPL WT gene transfer prolonged the survival of mice up to 21 days. In contrast, LPL S447X completely rescued 95% of the mice to adulthood and increased LPL catalytic activity in postheparin plasma 2.1-fold compared with LPL WT at day 3 ( P =0.003). LPL S447X also reduced plasma TG 99% from baseline ( P <0.001), 2-fold more than LPL WT , ( P <0.01) and increased plasma HDL cholesterol 2.9-fold higher than LPL WT ( P <0.01). These data provide in vivo evidence that the increased catalytic activity of LPL S447X improves plasma TG clearance and increases the HDL cholesterol pool compared with LPL WT .

Combination of apolipoprotein E2 and lipoprotein lipase heterozygosity causes severe hypertriglyceridemia during pregnancy

Pregnancy is a physiological condition where plasma triglyceride levels are moderately increased. This results from raised synthesis of very-low-density lipoproteins (VLDL) in response to elevated estrogen levels. The occurrence of marked hypertriglyceridemia (HTG) is rare and may result from combination of heterozygote mutation in the lipoprotein lipase (LPL) gene and apolipoprotein E2 isoform, as reported in this case. This observation illustrates the interaction between genetic and environmental factors, since pregnancy may disclose a silent LPL deficiency. The risk of acute pancreatitis threatens both the mother and fetus lives. Early recognition of severe HTG and appropriate management are essential for a successful pregnancy outcome.

Maternal triglyceride levels and newborn weight in pregnant women with normal glucose tolerance

OBJECTIVE

To determine the predictive value of serum triglyceride levels (TG) for neonatal weight in pregnant women with positive diabetic screening but normal glucose tolerance.

RESEARCH DESIGN AND METHODS

We enrolled 180 pregnant Caucasian women with positive diabetic screening. All women underwent a 3-h 100-g oral glucose tolerance test (OGTT) at 27th +/- 4 week of gestation. At the time of OGTT, we measured: fasting plasma glucose, fasting lipids profile and determined ApoE polymorphisms to evaluate the effects on lipid levels. In 83 women with normal glucose tolerance and at term delivery we evaluated the association between maternal serum TG, specific maternal parameters known to affect fetal growth and newborn weight.

RESULTS

Based on OGTT, gestational diabetes mellitus (GDM) was diagnosed in 36 women (20%), impaired glucose tolerance (IGT) in 23 (13%), and normal glucose tolerance (NGT) in 121 (67%). Serum TG concentration was significantly higher in women with GDM (2.47 +/- 0.77 mmol/l) as compared with NGT (1.99 +/- 0.64 mmol/l) or IGT (1.98 +/- 0.81 mmol/l) (P < 0.01). ApoE3 allelic frequency was 86%, ApoE2 and ApoE4 were 5 and 9%, respectively. We found no clear-cut association between apoE genotype and serum TG concentration. Macrosomia and LGA newborns were more frequent in IGT than in GDM or NGT (P < 0.01). In the 83 women with positive diabetic screening but normal glucose tolerance who delivered at term, the incidence of LGA infants was significantly higher in those with TG levels higher than the 75th percentile (> 2.30 mmol/l) (21%) than in mothers who had normal TG levels (4.5%) (P < 0.05). Pre-pregnancy BMI (r(2) = 0.067), weight gain during pregnancy (r(2) = 0.062), fasting serum TG (r(2) = 0.09), and 2-h post-OGTT glucose levels (r(2) = 0.044) were all associated with neonatal body weight (all P < 0.05 or less). However, on a multiple regression analysis, only pre-pregnancy BMI (F-test = 7.26, P < 0.01), and fasting serum TG (F-test = 4.07, P < 0.01) were independently associated with birth weight.

CONCLUSIONS

Pre-pregnancy BMI and fasting maternal serum TG determined in the last trimester of gestation were independently associated with neonatal birth weight in women with normal glucose tolerance, but positive screening test. TG levels measured in the third trimester of pregnancy are independent of the genetic polymorphism of ApoE.

Effect of n-3 fatty acids on serum lipid levels and hepatic fatty acid metabolism in BALB/c.KOR-Apoeshl mice deficient in apolipoprotein E expression

N-3 fatty acids exert a potent serum lipid-lowering effect in rodents mainly by affecting hepatic fatty acid oxidation and synthesis. However, it has been observed that fish oil and docosahexaenoic acid ethyl ester do not lower serum lipid levels in apolipoprotein E (apoE)-knockout (Apoetm1Unc) mice generated by gene targeting. To test the hypothesis that apoE expression is required for n-3 fatty acid-dependent regulation of serum lipid levels and hepatic fatty acid metabolism, we examined the effect of fish oil and n-3 fatty acid ethyl esters on the activity and gene expression of hepatic enzymes involved in fatty acid oxidation and synthesis using an alternative apoE-deficient mouse model with the BALB/c genetic background (BALB/c.KOR-Apoeshl). ApoE-deficient mice were fed diets containing 9.4% palm oil, fish oil, or 5.4% palm oil and 1% EPA plus 3% DHA ethyl esters for 15 days. In contrast to the reported data on apoE-knockout mice, fish oil and n-3 fatty acid ethyl esters greatly decreased serum triacylglycerol, cholesterol, and phospholipid levels in the Apoeshl mice. The decreases were greater with fish oil than with ethyl esters. The alterations by dietary n-3 fatty acids of serum lipid levels were accompanied by parallel changes in the activity and mRNA levels of enzymes involved in hepatic fatty acid oxidation and synthesis. The reason for the discrepancy between the results of the current study and previous studies is unknown. However, our study at least indicates that a lack of apoE expression does not necessarily accompany deficits in the n-3 fatty acid-dependent regulation of serum lipid levels and hepatic fatty acid metabolism.

Apolipoprotein E and cholesteryl ester transfer protein polymorphisms in normal and preeclamptic pregnancies

OBJECTIVES

To evaluate the association of apolipoprotein (apo) E polymorphism and a cholesteryl ester transfer protein (CETP) polymorphism (CETP/TaqIB) with preeclampsia and with lipid/lipoprotein profile in pregnancy.

MATERIALS AND METHODS

A group of 144 normal pregnant women (67 in the third trimester) were compared with 51 cases of preeclampsia in the third trimester of gestation. Apo E and CETP genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism. Serum lipids, lipoproteins and apolipoproteins were evaluated using commercially available kits. LDL size was assessed by gradient gel electrophoresis.

RESULTS

No differences were found in the distribution of subjects with respect to genotypes, in the apo E and CETP polymorphisms, between control and pathologic groups. In the third trimester of gestation (both control and case groups considered), apo E polymorphism, but not CETP polymorphism, was associated with different lipid and lipoprotein levels. Patients carrying the E2 allele (E2+) presented with significantly lower values of LDL cholesterol (LDLc) compared with carriers of E4 (E4+) and E3/3 individuals. E2+ also presented with the highest triglyceride (TG) level, although this was not statistically significant. On the other hand, HDL cholesterol (HDLc) and apo A-I levels were significantly reduced in E4+, compared with E3/3. Furthermore, E4+ presented with the highest total cholesterol and LDL and therefore LDLc/HDLc and apo B/apo A-I ratios were significantly higher in this group compared with the other two.

CONCLUSIONS

Neither of our candidate genes showed association with preeclampsia. However, apo E genotype was associated with changes in lipid and lipoprotein profiles in pregnant women.

Lipoprotein concentrations in newborns are associated with allelic variations in their mothers

BACKGROUND

Factors determining lipoprotein concentrations in the fetus are not yet fully understood. We postulated that an important factor is the genetic make-up of the mother. In the present study, we examined the associations between the cord blood concentrations of lipoproteins of 525 newborns and the polymorphisms present in their mothers on the genes of apolipoprotein E (APOE*E2, *E3, *E4), apolipoprotein C-III (APOC3*C3238G also called APOC3*S2) and lipoprotein lipase (LPL*S447X).

RESULTS

Newborns born of mothers with APOE*E2 allele had significantly lower cord blood LDL-C (P < 0.01) and apoB (P < 0.01) and significantly higher cord blood HDL-C and apoA1 (all P-values < 0.03) compared to those born of mothers with APOE*E3E3 genotype. These associations were independent of the presence of APOE*E2 allele in the newborns. Similarly, APOC3*S2 in mothers was associated with significantly lower (all P < 0.001) cord blood LDL-C, apoB, HDL-C and apoA1. In contrast, LPL*S447X in mothers lowered significantly cord blood LDL-C and apoB only when LPL*S447X was present in newborns. Most of the effects of these maternal polymorphisms on the newborns were independent of the changes of maternal lipoproteins generated by these polymorphisms.

CONCLUSIONS

This is the first evidence that maternal genetic variations influence fetal lipoprotein concentrations, independent of the genetic status of the fetus and of the variations of maternal lipoprotein concentrations generated by these genetic variants. It suggests that proteic components of maternal lipoproteins strongly control the metabolism of maternal lipoproteins carried out at the surface of the placenta to assure the cholesterol delivery to the fetus.

Genetics, the environment, and lipid abnormalities

Plasma lipid levels have been identified as major risk factors for cardiovascular disease. Multiple behavioral and environmental factors are known to modulate their concentrations in the general population; however, there is dramatic individual variability in the association between risk factors and disease, as well as in the individual response to therapeutic intervention. These differences may be due to the interaction between genetic and nongenetic factors that are ultimately responsible for the individual disease risk and response to intervention. Great strides have been made to characterize the genes involved in the homeostasis of plasma lipoprotein levels and to identify polymorphisms that could contribute to an earlier and more precise individual risk assessment. Especially relevant has been the recent interest and progress on examining the interaction between a number of candidate genes and nongenetic factors, namely smoking, alcohol drinking, physical activity, and sex. The APOE locus continues to be the most thoroughly studied gene in this regard; however, other genes (ie, LPL, APOC3, ADH3) are showing promising results.