Dysregulation of placental endothelial lipase and lipoprotein lipase in intrauterine growth-restricted pregnancies.
BACKGROUND
Fetal supply of maternally derived fatty acids requires lipase-mediated hydrolysis of lipoprotein-borne triglycerides and phospholipids at the placental surface.


OBJECTIVE
The objective of the study was to test the hypothesis that members of the triglyceride lipase gene (TLG) family are expressed in the human placenta at the maternoplacental (syncytiotrophoblast) and fetoplacental (endothelial cells) interface and that their expression is altered in pregnancy pathologies.


METHODS
Expression of TLG family members in primary placental cells (trophoblast and endothelial cells) and tissues of first-trimester and term human placenta was analyzed by microarrays, RT-PCR, Western blotting, and immunohistochemistry. Their expression was compared between normal pregnancies and those complicated with intrauterine growth restriction (IUGR).


METHODS
Participants included women with uncomplicated pregnancies and pregnancies complicated by IUGR.


RESULTS
Endothelial lipase (EL) and lipoprotein lipase (LPL) were the only lipases among the TLG family expressed in key cells of the human placenta. In first trimester, EL and LPL were expressed in trophoblasts. At term, EL was detected in trophoblasts and endothelial cells, whereas LPL was absent in these cells. Both lipases were found at placental blood vessels, EL in vascular endothelial cells and LPL in the surrounding smooth muscle cells. In total placental tissue EL expression prevails in first trimester and at term. Compared with normal placentas, EL mRNA was decreased (30%; P < 0.02), whereas LPL mRNA expression was increased (2.4-fold; P < 0.015) in IUGR.


CONCLUSIONS
EL is the predominant TLG family member in the human placenta present at both interfaces. EL and LPL are dysregulated in IUGR.
Gauster
M
M
Institute of Histology, Cell Biology, and Embryology, Center of Molecular Medicine, Medical University of Graz, Harrachgasse 21/VII, Graz, Austria. martin.gauster@meduni-graz.at
Hiden
U
U
Blaschitz
A
A
Frank
S
S
Lang
U
U
Alvino
G
G
Cetin
I
I
Desoye
G
G
Wadsack
C
C
D000328:Adult; D015153:Blotting, Western; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology / Q000201:enzymology*; D005192:Family Health; D005260:Female; D005317:Fetal Growth Retardation / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007150:Immunohistochemistry; D008049:Lipase / Q000235:genetics* / Q000378:metabolism; D008071:Lipoprotein Lipase / Q000235:genetics* / Q000378:metabolism; D008431:Maternal-Fetal Exchange; D020411:Oligonucleotide Array Sequence Analysis; D011247:Pregnancy; D014327:Trophoblasts / Q000166:cytology / Q000201:enzymology*
C410382:LIPG protein, human; D008049:Lipase; D008071:Lipoprotein Lipase