Tenascin Expression in Human Placentas during FGRAffected Pregnancies and Umbilical Doppler Velocimetry Correlation

Research Article

Austin J In Vitro Fertili. 2015;2(2): 1020.

Tenascin Expression in Human Placentas during FGRAffected Pregnancies and Umbilical Doppler Velocimetry Correlation

Locci M¹, Nazzaro G¹, Miranda M¹, Iazzetta R¹, Patrì A¹, D’Anna M², Castaldo C²* and Montagnani S²

¹Department of Nervous, “Federico II” University of Naples, Italy

²Department of Public Health, “Federico II” University of Naples, Italy

*Corresponding author: Castaldo C, Department of Public Health, “Federico II” University of Naples, via Pansini 5 80131 Naples, Italy

Received: June 03, 2015; Accepted: July 13, 2015; Published: June 15, 2015


Objective: The aim of this study was to evaluate the expression of some non collagenous extracellular matrix proteins, in particular tenascin, in human placentas of intrauterine growth restricted fetuses with abnormal umbilical Doppler velocimetry.

Study Design: Study group (group A) consisted of 23 pregnant women with intrauterine growth restricted fetuses, with or without preeclampsia. Control group (group B) consisted of 10 pregnant women with appropriate fetal weight for gestational age. Placental specimens were collected from biopsies obtained after cesarean delivery. Umbilical artery Doppler velocimetry was performed within four hours from delivery in all patients. Tenascin expression was studied by immunohistochemistry and western blot techniques.

Results: A difference in birth weight and placental weight was found in the two groups, being lower in the study group. Umbilical artery Doppler velocimetry showed abnormal patterns in the study group and normal findings in the control one. Tenascin was strongly expressed in placentas from growth restricted fetuses, as shown by immunohistochemistry and by RT-PCR, while it was almost absent in placentas from group B.

Conclusion: A relationship between abnormal Doppler patterns and tenascin distribution in growth restricted fetuses has been observed. The presence of tenascin might be considered as a placental compensatory mechanism in FGR fetuses with abnormal umbilical artery Doppler velocimetry.

Keywords: Fetal growth restriction, Tenascin, umbilical Doppler velocimetry, Extracellular Matrix


FGR: Fetal Growth Restriction; PE: Preeclampsia; ROS: Reactive Oxygen Species; SOD: Superoxide Dismutase; ECM: Extracellular Matrix; MMPs: Matrix Metalloproteinase’s; AGA: Appropriate for Gestational Age; AC: Abdominal Circumference; LBW: Low Birth Weight; VLBW: Very Low Birth Weight; PI: Pulsatility Index; AEDF: Absent End-Diastolic Flow; REDF: Reversed End-Diastolic Flow; VEGFR: Vascular Endothelial Growth Factor Receptor-2.


Fetal Growth Restricted (FGR) fetuses are the fetuses in which growth restriction implies a pathological restriction of the genetic growth potential. As a result, FGR fetuses manifest evidence of fetal compromise i.e. abnormal Doppler velocimetry [1]. FGR with or without Preeclampsia (PE) complicates a significant number of pregnancies [2,3]. This condition is an important risk factor for adverse perinatal outcome and contributes to maternal and perinatal morbidity and mortality. Impaired placental perfusion and angiogenesis seem to be the most common causes of FGR, even if, in some cases, both FGR and PE are related to a failure of immunomodulatory placental functions [4,5]. Moreover, excessive levels of placental oxidative stress lead to PE and FGR, and placental hypoxia-reoxygenation is a potential cause of such stress. High levels of Reactive Oxygen Species (ROS) may induce cellular apoptosis. Thus, ROS-scavenging enzymes, such as Superoxide Dismutase (SOD) enzyme family, are important for preserving fetal growth [6]. Several placental histological and morphological abnormalities such as infarcts, terminal villous fibrosis and impaired trophoblastic invasion have been well described in FGR placentas [7-10]. Many studies have reported an association between abnormal Doppler velocimetry changes in umbilical artery and adverse perinatal outcome in growth restricted fetuses. The correlation between placental morphology and umbilical artery Doppler velocimetry, an indicator of placental vascular resistance, shows that substantial changes in the growth of villi and in fetal vasculature can reduce maternal-fetal exchanges of nutrients and oxygen and contribute to fetal hypoxic stress [11].

The human placenta, as a boundary organ between mother and fetus, plays a dynamic role in establishing and maintaining pregnancy through a multifunctional way involving continuous rearrangement in its structure. It is now widely accepted that the Extracellular Matrix (ECM) is a dynamic and highly specialized structure, involved in several signal transduction pathways [12]. For instance, ECM proteins are degraded by Matrix Metalloproteinases (MMPs), endopeptidase capable of processing a number of bioactive molecules. They are released by placental cells during tissue remodeling processes, cell migration and neoangiogenesis: aberrations in MMPs activity in early pregnancy can play a role in the physiopathology of conditions like FGR [13]. It has been recently suggested that ECM proteins, such as fibronectin, tenascin and laminin, play different roles in cell proliferation, migration and differentiation. Tenascin, in particular, has shown to be able in modulating cellular adhesion by increasing or decreasing it, and seems to be involved in the immunological protection of the embryo during implantation. Moreover, tenascin seems to be involved in villous repairing after placental infarctions and in neoangiogenic mechanisms [14,15]. Also fibronectin, which often co-distributes with tenascin, and laminin, can induce migration of cell populations and metabolites [16]. Cell–matrix interactions represent a so important phenomenon that we can hypothesize that some changes in the structure and in the distribution of these proteins are involved in pregnancies complicated by FGR. Moreover, tenascin, whose expression has been correlated with villous growth, cells proliferation and fibrinoid deposition, may play a critical role in placental homeostasis development throughout pregnancy [14]. Tenascin is a large ECM glycoprotein. Until now five isoforms are known: tenascin-C, or cytotactin, which plays a regulatory role on neuron morphology and adhesion, representing the most abundant form [17], tenascin-X, whose gene is on chromosome 6 and is typically detected in muscles, tenascin-Y distributed on muscletendon junctions, tenascin-J or janusin, exclusive of the nervous tissue and tenascin-R which is synthesized by oligodendrocytes during mielinization [18].

Tenascin-C is mostly expressed in the mesenchymal villi, cell islands and columns. These structures are the proliferating units of the villous trees. Probably this molecule is involved in angiogenesis. In addition, tenascin separates fibrinoid deposits at the surface of the villous trees from the fetal stroma. This location suggests a role of such protein in placental repair mechanisms and in immunoprotection of fetal tissues [19].

In the present study we have investigated the placental expression of non collage nous ECM components such as fibronectin and tenascins in pregnancies complicated by FGR with or without PE, with abnormal umbilical artery Doppler findings. Our attention was particularly appointed on the expression of tenascin-C, as this protein is involved in various aspects of cell and tissue development and in cell-to-cell and cell-to-substrate adhesion.

Our study includes a control group of healthy pregnancies with appropriate fetal gestational age and normal umbilical artery Doppler waveforms.

Patients and Methods


A number of 33 Caucasian pregnant women were recruited between January 2010 and December 2013. On the total, 23 patients affected by FGR, with or without PE, were considered for the study group (group A). All patients of the group A were submitted to cesarean section. The control group (group B) consisted of 10 pregnant women with appropriate fetal growth, homogeneous for age, BMI (20-25 kg/m2), socioeconomic status and gestational age to the group A (Table 1). In the group B, abnormal presentation and previous cesarean section were the indications for cesarean section. Gestational age was calculated using the crown-rump length ultrasonographic determination in the first trimester, according to the last menstrual period. Ultrasound criteria were applied to assess fetal growth. Fetuses were considered Appropriate for Gestational Age (AGA) if Abdominal Circumference (AC) was found between 10th and 95th percentile. Fetuses were considered affected by FGR, if abdominal circumference was found below the 10th percentile of our standard population fetal growth curves. At delivery, neonates were consisted Low Birth Weight (LBW) if neonatal weight was less than 2,500 g and Very Low Birth Weight (VLBW) if less than 1,500 g.