Intra-Amniotic Infection Upregulates Decidual Cell Vascular Endothelial Growth Factor (VEGF) and Neuropilin–1 and –2 Expression: Implications for Infection-Related Preterm Birth

Abstract

Intra-amniotic infection/inflammation (IAI) is a major cause of preterm birth, but the mechanisms responsible are not well understood. This study investigates the effects of IAI on vascular endothelial growth factor (VEGF) as well as VEGF receptor (Flt1, KDR2) and coreceptor (neuropilin-1 and -2) messenger RNA (mRNA) and protein expression at the maternal-fetal interface, both in vitro and in vivo. Decidual stromal cells (DSCs) were isolated from term placentae, purified, and treated with 10(-8) mol/L estradiol (E(2)), 10( -7) mol/L medroxyprogesterone acetate (MPA), both, or vehicle for 7 days. Vascular endothelial growth factor expression in cultured DSCs increased in response to stimulation with interleukin 1 beta (IL-1 beta; 0.01-10 ng/mL)--but not tumor necrosis factor alpha (TNF-alpha; 1 ng/mL)--in a concentration-dependent fashion irrespective of the hormonal milieu. This effect appears to be mediated at the level of gene transcription because stimulation with IL-1 beta (but not TNF-alpha) increased expression of VEGF mRNA as measured by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR); a similar increase was seen in neuropilin-1/-2 (but not Flt1 and KDR2) mRNA. Immunohistochemical studies confirmed these observations in vivo. Immunostaining for VEGF and neuropilin-1/-2 (but not Flt1 or KDR2) was increased in serial tissue sections of decidua from women with clinical and histological evidence of IAI versus noninfected controls, and in cultured term DSCs exposed to IL-1 beta. The novel observations that IL-1 beta stimulates VEGF and neuropilin-1/-2 mRNA and protein expression in term DSCs in vitro along with confirmatory in vivo data using immunohistochemistry provide a mechanism by which IAI can alter vascular permeability, thereby facilitating leukocyte trafficking and increasing the risk of abruption, both of which are associated with preterm birth.

Protein Deficiency and Intestinal Nematode Infection in Pregnant Mice Differentially Impact Fetal Growth through Specific Stress Hormones, Growth Factors, and Cytokines>

“…Together, these results demonstrated that a reduction in inflammation because of increased maternal regulatory cytokines may be beneficial for growth and development of certain fetal organs. For putative organ-specific growth factors, f-VEGF was positively associated with fetal brain, kidney, and lung masses, which contrasts with reports that placental VEGF is associated with preterm birth (58). Our finding that m-VEGF and af-VEFG were negative predictors of fetal mass suggests that f-VEGF may be an organ-specific growth factor.…”

Role of GnRH–GnRH receptor signaling at the maternal-fetal interface

“…2). Consistent with earlier publications (23,30), IL-1b did not stimulate sFlt-1 production by HTR-8/SV neo cells (Fig. 2F).…”

“…First-strand complementary DNA (cDNA) was generated by reverse transcription (RT) of 1 mg RNA using p(dT) [12][13][14][15][16][17][18] primers with MMLV-reverse transcriptase (Invitrogen) and amplified as previously described (23,24). The polymerase chain reaction (PCR) products were separated by gel electrophoresis in 1.5% agarose and visualized by ethidium bromide staining on an ultraviolet transilluminator.…”

Isolation of Leukocytes from the Human Maternal-fetal Interface

“…After dissociation, the leukocytes are enriched from the total population of the decidual cells by density gradient centrifugation. Various density gradient media have been previously utilized, the most common of which are Percoll (a suspension of colloidal silica particles) 48 and Ficoll (a polymer of sucrose with a high synthetic molecular weight) 49 . The superior efficiency of isolation by the sucrose polymer has been previously shown 50 , and the protocol described herein further proves that this density gradient media produces a sufficiently high purity of mononuclear leukocytes.…”