**6. Acknowledgment**

We express our sincere thanks to physicians who performed fetal blood samplings and allowed us to realize this work (Department of Obstetrics and Gynecology, Hôtel-Dieu Hospital, Lyon, France).

#### **7. References**

176 From Preconception to Postpartum

The decrease in cholesterolemia may be related to growth problems which are often associated with morphological anomalies. The fundamental role of cholesterol in embryo development is well established, and anomalies in cholesterol synthesis are involved in a number of human malformation syndromes (Porter et al., 2003; Guizzetti et al., 2005).

We studied a group of 53 fetuses with malformations of varying clinical expression and severity, and measured in the fetal blood essential biochemical parameters which may be associated with fetal well-being; the results obtained were compared with those from a

The disparity in the populations studied make the interpretation of the results difficult. Around 20% of the pathological pregnancies are accompanied by a state of fetal distress with acid-base balance alterations. Gaseous acidosis is present in the cardiac malformations; acidosis is mixed in the malformations of the central nervous system and pulmonary malformations, and is essentially metabolic in the case of fetoplacental

The gasometric anomaly most frequently encountered is hypoxemia, present in around 40%

The reduction in the umbilical venous pO2 probably reflects an impaired transplacental transfer of respiratory gases and placental dysfunction; it may also be related to a maternal cause (such as an episode of hypoxemia), or a properly fetal cause such as fetal

Metabolic anomalies, often less common, are associated with acid-base anomalies. The decrease in umbilical venous glucose, found in 18% of the pathologies studied, leads to a suspicion of a reduced transplacental passage of glucose, in parallel to the reduced diffusion

Conversely, the umbilical venous hyperglycemia present in some cases, is secondary to a maternal hyperglycemia and probably associated with a diabetic or pre-diabetic state in the

Changes to concentrations of lactate, free fatty acids, ketone bodies and cholesterol are markers of a disrupted fetal metabolism. Hyperlactatemia is associated with impaired

The reduction in umbilical venous cholesterolemia found in some pregnancies reflects defective metabolic conditions in the fetus. It has possible consequences on fetal growth and is possibly linked to the morphological anomalies found, with cholesterol being an essential

The results obtained are however a reflection of an instantaneous measurement and the

Moreover, in nearly 50% of cases, the blood chemistry and the in utero living conditions of the fetus with congenital malformations are not very disrupted compared with those of the

biochemical anomalies found may be a consequence of the malformations.

group of 73 fetuses with normal growth and morphology.

of observations and in almost all types of pathology.

oxygenation conditions and inadequate placental clearance.

constituent for the development of the embryo.

normally constituted fetus.

**5. Conclusion** 

anasarca.

anemia.

of oxygen.

mother.


**11** 

*Greece* 

**Placental Angiogenesis and** 

Victor Gourvas1, Efterpi Dalpa2, Nikos Vrachnis3 and Stavros Sifakis4

*4Department of Obstetrics & Gynecology, University Hospital of Heraklion, Crete,* 

The process that involves vessel formation and growth has been described by the terms vasculogenesis and angiogenesis, as two distinct types [Demir et al., 2007]. Both of these

a. vasculogenesis, meaning new blood vessel formation from hemangiogenic stem cells (derived from mesenchymal cells) that differentiate to hemangioblastic stem cells, essentially occurring during fetal development. Vasculogenesis consists of three major steps: i. induction of hemangioblasts and angioblasts -mediated mainly through fibroblast growth factor (FGF), ii. assembly of primordial vessels -mediated mainly by vascular endothelial growth factor/vascular endothelial growth factor receptor system (VEGF/VEGFR) iii. transition from vasculogenesis to angiogenesis [Flamme et al.,

b. angiogenesis, meaning new branches from pre-existing vessels, which is occurring in the female reproductive tract during the formation of the corpus luteum, during endometrial development and during embryo implantation and placentation. Two forms of angiogenesis have been described: sprouting and non-sprouting angiogenesis (intussusception) [Folkman et al., 1992]. The process of angiogenesis has three phases:

The vascularisation of placental villi starts at day 21 post conception (dpc), being the result of local de novo formation of capillaries rather than protrusion of embryonic vessels into the placenta [Demir et al., 1989]. Mesenchymal cells inside the villi transform into hemangiogenic precursor cells that migrate toward the periphery. In the latter, prior to the formation of the first vessels that are observed by about 28 dpc (erythrocytes are detected by 32 dpc), mesenchymal derived macrophages (Hofbauer cells) appear. Those macrophages will express angiogenic growth factors and, as they appear early, they suggest a paracrine role in the initiation of vasculogenesis. Angiogenic growth factors are also expressed by the

initiation, proliferation-invasion and maturation-differentiation.

**1. Introduction** 

1997];

**1.1 Vessel growth and angiogenesis** 

processes are essential for normal uteroplacental development:

*1Department of Pathology, General Hospital "G. Genimatas", Thessaloniki, 2Department of Pediatrics, General Hospital "G. Papageorgiou", Thessaloniki,* 

*32nd Department of Obstetrics & Gynecology, Aretaieion Hospital,* 

**Fetal Growth Restriction** 

*University of Athens, Athens,* 

