Identifying HDL Composition and Function in Preeclamptic and Normal Pregnancies
Condition: HDL Cholesterol; Preeclampsia; Saliva
MeSH terms: Pre-Eclampsia
Study type: Observational

Summary: 
      The study is design to assess if there is a correlation between diagnosis of preeclampsia and
      its severity to changes in HDL quality, in terms of composition and function and to determine
      whether preeclampsia-induced changes in VOCs in saliva can be used for the early diagnosis of
      preeclampsia.
    

Detailed description: 
      Scientific background Preeclampsia is a syndrome characterized by the onset of hypertension
      and proteinuria or other end-organ dysfunction. It develops after 20 weeks of gestation and
      can cause significant maternal and fetal morbidity and mortality (1,2). The pathophysiology
      of preeclampsia is thought to be developmental abnormalities of placental vasculature leading
      to placental under-perfusion or ischemia. This ischemia is believed to mediate the release of
      anti-angiogenic factors into the maternal circulation, causing endothelial dysfunction,
      hypertension and end-organ injury (2). The elemental factor that leads to the development of
      placental vasculature abnormalities is still to be elucidated. However, histological changes
      in the placenta include atherosis (lipid laden cells in the wall of the arteriole), fibrinoid
      necrosis, thrombosis, sclerotic narrowing of arterioles, and placental infarction, all of
      which are similar to findings seen in atherosclerotic plaque (1-3). Another close association
      between the mechanisms of preeclampsia and atherosclerosis was found in large epidemiological
      studies that demonstrated a strong correlation between preeclampsia (PET) and the development
      of cardiovascular disease later in life (4). Women with PET are more likely than those with
      normal pregnancy to develop chronic hypertension, cardiovascular disease, stroke, diabetes
      and end-stage renal disease (1,4).Common atherosclerotic diseases, such as hypertension,
      chronic kidney disease (CKD), hypercholesterolemia and diabetes are strongly associated with
      preeclampsia during pregnancy (5-6).

      Large epidemiologic and experimental studies have shown an association between low levels of
      high density lipids (HDL) in the blood and increased cardiovascular risk (7). The
      cardioprotective properties of HDL are thought to be composed of several mechanisms,
      including regulation of endothelial functions that enhance NO production and maintaining
      endothelial integrity, as well as anti-inflammatory, anti-oxidative and anti-thrombotic
      effects (8-9). However, pharmacological studies reported that increases in plasma HDL did not
      improve cardiovascular outcomes (10-12).

      At the same time, emerging data have revealed the importance of the quality of the HDL more
      than its quantity. HDL from patients with CKD was found to lose its anti-atherogenic and
      endothelial protective effects. In a study by Shroff et al. (13), HDL from patients with CKD
      was incubated with a primary endothelial cell line. Several endothelial functions, such as
      reduced NO production, permission of SO production, increased VCAM-1 expression and reduction
      of cholesterol efflux capacity were decreased compared to those of HDL from healthy
      individuals. These effects were associated with vascular dysfunction markers in those
      patients, such as high levels of urate, angiopoeitin and IL-6, as well as poor vascular
      function measurements, as measured by aortic pulse velocity and carotid intima media
      thickness. These negative functions increased as CKD severity progressed and showed a partial
      improvement after kidney transplantation (13).

      Information regarding the composition and function of serum lipids and lipoproteins among
      preeclamptic pregnancies compared to normal pregnancies is scarce. Early pregnancy
      dyslipidemia, particularly hypertriglyceridemia appears to be associated with increased risk
      of preeclampsia (14). However, equivocal results were found regarding paraoxonase 1 (PON1)
      activity, which is an antioxidative enzyme found in HDL that inhibits low density lipid (LDL)
      and HDL oxidation. PON1 activity is decreased in diseases associated with endothelial
      activation and dysfunction including diabetes, hypercholesterolemia and cardiovascular
      disease (15). Demir et al. (16) found low levels of HDL, ApoA1 and paraoxonase activity in
      preeclamptic compared to normal pregnancies, whereas Acikgoz et al. (17) demonstrated
      significantly higher PON1 activity in preeclamptic compared to normal pregnancies.

      Saliva contains constituents that reflect a diseased or physiologic state of the human body
      and hence could be utilized for diagnostic purposes. The sources and composition of whole
      saliva (oral fluid) are unique and complex. Saliva consists of secretions from salivary
      glands and gingival crevicular fluid, oral mucosa transudate, secretions from nasal and
      pharyngeal mucosa, nonadherent bacteria, desquamated oral epithelial cells, keratin debris,
      blood cells, and possibly food or medication residuals (18). Its functions include
      lubrication, digestion, antimicrobial activity, facilitating remineralization of dental
      enamel, and maintaining normal taste sensation (19). These important functions are achieved
      by the various chemical components of saliva including water, inorganic compounds (ions),
      organic compounds (non-proteins and lipids), protein/polypeptides, and hormones (19). The
      search for reliable salivary biomarkers has developed rapidly, especially in oral cancers,
      spurred by the fact that collecting saliva is simpler and less invasive than drawing blood.

      Salvador-Moysén et al. (20) aimed to determine the usefulness of salivary cortisol as a
      predictor of preeclampsia in adolescents. They found that cortisol concentrations >14.9
      nmol/L were observed in the group that developed preeclampsia, whereas the control group had
      values <10.1 nmol/L.

      Volatile organic compounds (VOC) can be detected in the breath and blood and used for the
      early detection and characterization of the development and progression of diseases (21).
      Many of the VOC that are detected in the breath are systemic or endogenous and are produced
      during physiological processes, but the metabolic routes behind their production are known
      for only a few (22). Other VOCs are exogenous and result from external contamination through
      inhaled air or ingested foods or drinks.

      Solid phase microextraction (SPME) is a simple, automated, rapid technique for VOC detection
      combined with gas chromatography-mass spectrometry (GC-MS) (20). To the best of our
      knowledge, no studies have been conducted to identify VOC in saliva from preeclamptic women.

      Objectives

        1. There is a correlation between diagnosis of preeclampsia and its severity to changes in
           HDL quality, in terms of composition and function.

        2. Determine whether preeclampsia-induced changes in VOCs in saliva can be used for the
           early diagnosis of preeclampsia.

      Research goals

        1. Assess:

           HDL composition and function of normal and preeclamptic pregnancies at weeks 12-14
           (second trimester), weeks 28-30 (third trimester) and at delivery Apo-A1 properties,
           PON1 activity HDL size HDL lipid content HDL antioxidant activity (toward LDL and
           macrophages) HDL-mediated cholesterol efflux from macrophages

        2. Evaluate the effects of HDL from women with PET, normal pregnancies and non-pregnant
           women, on primary endothelial culture regarding proteins, mRNA and miRNAs, which are
           significant components in normal endothelial function and related to inflammatory
           response.

        3. Evaluate differences in the genomic and lipid profiles of cord blood and placentas from
           women with PET, normal pregnancies and non-pregnant women

        4. Identify VOC in saliva, as early biomarkers of PET during the second and third
           trimesters and at delivery.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Pregnant woman followed in Community Obstetric Clinics and in the High Risk Obstetric
        Clinic at Meir Medical Center who agree to participate in the study.

        Woman will be recruited based on the presence of one or more risk factors for the
        development of preeclampsia including: first pregnancy, overweight at the beginning of
        pregnancy or significant weight gain during pregnancy , previous history of preeclampsia
        and a first degree family member with a history of preeclampsia
      
Keywords: HDL; Preeclampsia; saliva