Detection and Identification of Preeclampsia Via Volatile Biomarkers
Condition: Pregnancy; Death of Fetus, Early Pregnancy; Uremia in Pregnancy Without Hypertension
MeSH terms: Pre-Eclampsia
Study type: Observational

Summary: 
      Preeclampsia is a form of hypertension that is unique to human pregnancy. The incidence of
      the disease ranges between 2 and 7 percent in healthy nulliparous women. The etiology of
      preeclampsia is unknown.

      Women with preeclampsia may exhibit a symptom complex ranging from minimal BP elevation to
      derangements of multiple organ systems. The renal, hematologic, and hepatic systems are most
      likely to be involved.

      More than 100 clinical, biophysical, and biochemical tests have been recommended to predict
      or identify the patient at risk for the future development of the disease.

      The results of the pooled data for the various tests and the lack of agreement between serial
      tests suggest that none of these clinical tests is sufficiently reliable for use as a
      screening test in clinical practice. As a result there is obviously a great need to develop a
      novel technology for the early detection of this pregnancy complication before its clinical
      manifestations appear. An early detection can help in early treatment to prevent or at least
      minimize the sequel of this disease.

      The aim of this project is the early detection of "Preeclampsia" and other pregnancy
      complications using volatile biomarkers appearing in exhaled breath and/or blood samples,
      using a simple and inexpensive toll termed NA-NOSE.

      Phase-I: The primary phase of this project is the comparison between volatile biomarkers'
      patterns of pregnant women suffering from "Preeclampsia", pregnant women that are considered
      to have "Normal Pregnancy", and healthy "Non-Pregnant" women.

      Phase-II: The secondary phase of this project is the ability to predict "Preeclampsia", as
      compared, head-to-head, with other potential predictors used in the current clinical
      practice.
    

Detailed description: 
      Preeclampsia is a form of hypertension that is unique to human pregnancy. The clinical
      findings of preeclampsia can manifest as either a maternal syndrome (hypertension and
      proteinuria with or without other multisystem abnormalities) or as a fetal syndrome (fetal
      growth restriction, reduced amniotic fluid, and abnormal oxygenation).

      The incidence of preeclampsia ranges between 2 and 7 percent in healthy nulliparous women. In
      these women, preeclampsia is generally mild, with the onset near term or intrapartum (75
      percent of cases), and the condition conveys only a minimally increased risk for adverse
      pregnancy outcome. In contrast, the incidence and severity of preeclampsia are substantially
      higher in women with multifetal gestation, chronic hypertension, previous preeclampsia,
      pregestational diabetes mellitus, and in those with preexisting thrombophilias.

      The etiology of preeclampsia is unknown. Many theories have been suggested, but most of them
      have not withstood the test of time. Some of these theories: Abnormal trophoblast invasion,
      coagulation abnormalities, vascular endothelial damage, cardiovascular maladaptation,
      immunologic phenomena, genetic predisposition and dietary deficiencies or excesses.

      Preeclampsia is a clinical syndrome that embraces a wide spectrum of signs and symptoms that
      have been clinically observed to develop alone or in combination. The classic triad of
      preeclampsia includes: hypertension, proteinuria, and edema. However, there is now universal
      agreement that edema should not be considered as part of the diagnosis of preeclampsia. The
      diagnosis of preeclampsia requires the presence of an elevated blood pressure (BP) with
      proteinuria,3 usually starting after the 20th week of the pregnancy, but the severity of the
      disease process is generally based on the maternal BP which is considered as the traditional
      hallmark for diagnosis of the disease.

      Women with preeclampsia may exhibit a symptom complex ranging from minimal BP elevation to
      derangements of multiple organ systems. The renal, hematologic, and hepatic systems are most
      likely to be involved.

      Renal function is usually impaired in almost every case as proteinuria is always found. In
      preeclampsia, vasospasm and glomerular capillary endothelial swelling (glomerular
      endotheliosis) lead to an average reduction in GFR (glomerular filtration rate) of 25 percent
      below the rate for normal pregnancy. Serum creatinine is rarely elevated in preeclampsia, but
      uric acid is commonly increased. Despite the fact that uric acid levels are elevated in women
      with preeclampsia, this test is not sensitive or specific for the diagnosis of the disease.

      The liver is not primarily involved in preeclampsia, and hepatic involvement is observed in
      only 10 percent of women with severe preeclampsia. Fibrin deposition has been found along the
      walls of hepatic sinusoids in preeclamptic patients with no laboratory or histologic evidence
      of liver involvement. When liver dysfunction does occur in preeclampsia, mild elevation of
      serum transaminase is most common. Bilirubin is rarely increased in preeclampsia, but when
      elevated, the indirect fraction predominates. Elevated liver enzymes are part of the of HELLP
      syndrome, a variant of severe preeclampsia.

      Thrombocytopenia is the most common hematologic abnormality in women with preeclampsia. It is
      correlated with the severity of the disease process and the presence or absence of placental
      abruption. A platelet count of less than 150,000/mm3 has been reported in 32 to 50 percent of
      women with severe preeclampsia, And in 15 percent of cases of women with hypertension during
      pregnancy.

      Review of the literature reveals that more than 100 clinical, biophysical, and biochemical
      tests have been recommended to predict or identify the patient at risk for the future
      development of the disease.

      The results of the pooled data for the various tests and the lack of agreement between serial
      tests suggest that none of these clinical tests is sufficiently reliable for use as a
      screening test in clinical practice. As a result there is obviously a great need to develop a
      novel technology for the early detection of this pregnancy complication before its clinical
      manifestations appear. An early detection can help in early treatment to prevent or at least
      minimize the sequel of this disease.

      Volatile Biomarkers of Preeclampsia:

      The intensity of oxidative stress in women having normal pregnancy, preeclampsia, and
      nonpregnant women, as expressed by volatile biomarkers through exhaled breath, was studied by
      GC-Chromatography/Mass-Spectrometry (GC-MS)by the group of Moretti and Phillips. A 3-D
      display of abundance of C4-C20 alkanes and monomethylated alkanes showed that the mean volume
      under curve was significantly higher in preeclampsia patients than in normal pregnant women
      (P<003) and nonpregnant control subjects (P<005). A predictive model employing five volatile
      biomarkers (undecane, 6-methyltridecane, 2-methylpentane, 5-methyltetradecane, and
      2-methylnonane) distinguished preeclampsia from uncomplicated pregnancy (sensitivity=92.3%,
      specificity=89.7%; cross-validated sensitivity=88.5%, specificity=79.3%). While promising,
      the clinical value of this breath test as a predictor of preeclampsia is still unknown. This
      could be attributed to the fact that the study focused only on the oxidative stress relation
      to the preeclampsia at the time metabolic pathways cannot be ignored.

      A support for the latter comes from the involvement of many disorders (e.g., renal,
      hematologic, and hepatic), which has been found to emit volatile biomarkers, during the
      preeclampsia.

      Putting this preliminary study into wider perspective, longitudinal studies are required to
      determine if increased breath biomarkers of oxidative stress, and, also, metabolic pathways
      during earlier stages of pregnancy can predict the onset of preeclampsia. While part of the
      required knowledge could be gained by means of mass-spectrometry techniques, the use of these
      techniques are impeded by the need for expensive equipment, the high levels of expertise
      required to operate such instruments, the speed required for sampling and analysis, and the
      need for preconcentration techniques (a technique that allows detecting only part (15-20%) of
      the volatile biomarkers found in the real exhaled breath).

      For preeclampsia's volatile biomarker testing to become a clinical reality, several advances
      in the knowledge of specific preeclampsia volatile biomarkers and sensor development need to
      occur. Chemical sensor matrices, based on nanomaterials, are more likely to become a clinical
      and laboratory diagnostic tool, because they are significantly smaller, easier-to-use, and
      less expensive. An ideal chemical sensor for volatile biomarker analysis should be sensitive
      at very low analyte concentrations in the presence of water vapour (as breath samples contain
      80-90% RH). Furthermore, it should respond rapidly and differently to small changes in
      concentration, and provide a consistent output that is specific to a given exposure.

      Objectives:

      The aim of this project is the early detection of "Preeclampsia" and other pregnancy
      complications using volatile biomarkers appearing in exhaled breath and/or blood samples,
      using a simple and inexpensive toll termed NA-NOSE.

      Phase-I: The primary phase of this project is the comparison between volatile biomarkers'
      patterns of pregnant women suffering from "Preeclampsia", pregnant women that are considered
      to have "Normal Pregnancy", and healthy "Non-Pregnant" women.

      Phase-II: The secondary phase of this project is the ability to predict "Preeclampsia", as
      compared, head-to-head, with other potential predictors used in the current clinical
      practice.

      Methodology:

      Study Design and Outline:

      Phase-I of this study will concentrate on a cross sectional breath tests of three groups of
      young women who agreed to participate and signed an informed consent form that was approved
      by the institutional Helsinki committee in the Nazareth Hospital.

      Groups:

        -  Preeclampsia: 30 preeclamptic pregnant women with gestational age >24 weeks and no
           chronic medical disorders who are not in labor and their fetus is alive. Preeclampsia is
           defined as blood pressure of >140/90 mm Hg on 2 separate occasions at least 4 hours but
           not more than one week apart with proteinuria. Proteinuria is defined as a urinary
           dipstick value >1+ (30mg/dL), or a 24 hour urine collection with a protein excretion of
           >300mg.

        -  Uncomplicated pregnancy: 30 normotensive pregnant women with gestational age >24 weeks
           and no chronic medical disorders who has no obstetrical problems, not in labor and their
           fetus is alive.

        -  Healthy controls: 30 healthy non-pregnant control women recruited mainly from employees
           of the Nazareth Hospital who are healthy, not on medications and has not delivered a
           baby or conceived during the year before the breath collection.

      Breath Test Sampling for the NA-NOSE as well as the blood samples will be done in the
      Technion.

      Chemical analysis:

      The LNBD group (Technion) will determine the most pronounced electrical features for each
      organically functionalized nanosensor in response to the volatile biomarkers (of both breath
      and blood samples), and of the entire sensor array, using classical multi-linear regression
      models and neural network models. Different linear and nonlinear algorithms will be sought
      based on principal component analysis and chaotic parameters in order to reduce the
      dimensions of the data, and to extract the most important information. The exhaled air will
      also be analyzed by Gas-Chromatography/Mass-Spectrometry (GC-MS) in conjugation with thermal
      desorption for determining the nature and composition of the volatile biomarkers in the
      related breath and blood samples.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        women treated in the Nazareth Hospital and Emek Medical Center
      
Biospecimen description: 
      Breath Serum
    
Keywords: Pregnancy; Preeclampsia; Volatile biomarkers; Chemical sensors; Nanomaterials; Nanosensors; NA-NOSE