Expression of placental low-density lipoprotein receptor-related protein and scavenger receptors AI/AII transcripts in the baboon

Objective: This study was undertaken to assess potential secondary lipoprotein-dependent mechanisms, scavenger receptor AI and AII (SR-AI and SR-AII), and low-density lipoprotein (LDL) receptor-related protein (LRP) in the baboon (Papio sp) placenta. Study Design: Baboon placental villous tissue and enriched fractions of syncytiotrophoblast cells were collected at early ( day 60, n = 3), mid ( day 100, n = 4), and late ( day 160, n = 4) pregnancy (term = 184 days). The abundance of messenger RNA (mRNA) transcripts for SR-AI, SR-AII, and LRP were determined relative to constitutively expressed, glyceraldehyde-3-phosphate-dehydrogenase (GAPDH). Results: No quantitative differences (P> .05) in SR-AI, SR-AII, or LRP mRNAs were noted in respect to stage of gestation. However, SR-AII/GAPDH mRNA ratios in syncytiotrophoblast cells (0.38 ± 0.09, n = 11) were significantly (P< .05) higher than in villous tissue (0.15 ± 0.04, n = 11), whereas LRP/GAPDH mRNA ratios were higher in villous tissue (0.43 ± 0.10, n = 11) than in syncytiotrophoblast cells (0.18 ± 0.02, n = 11). Conclusion: SR-AII mRNA in baboon placenta appears to be expressed, in greatest abundance, in the endocrinologically active syncytiotrophoblast. (Am J Obstet Gynecol 2003;188:1211-3.)