PubMed · 13846537
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Y C YIN, S J LI. 1959. Amniotic fluid embolism.. https://pubmed.ncbi.nlm.nih.gov/13846537/
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OBJECTIVE: Intrauterine infection is associated with increased lipopolysaccharide (LPS) and proinflammatory cytokines in amniotic fluid. We hypothesized that intra-amniotic LPS launches a fetal inflammatory response leading to cardiac dysfunction. METHODS: A mouse model was established. At 15-16 days of gestation, 52 fetuses of nine dams received LPS and 46 fetuses of nine dams vehicle intra-amniotically. Five dams underwent a sham operation. Echocardiography was performed before and 6 h after the injection to obtain inflow and outflow blood velocity waveforms. Outflow mean velocity (V(mean)) and the proportions of isovolumetric relaxation (IRT%) and contraction (ICT%) times of the cardiac cycle were calculated. Pulsatility indices (PI) were calculated from the umbilical and intracranial arteries and the descending aorta. Pulsatility indices for veins (PIV) were obtained from ductus venosus. Toll-like receptor-4 (TLR4) and several other inflammatory mediators were determined using ELISA, immunohistochemistry, or ribonuclease protection assay. RESULTS: In the LPS group, outflow V(mean) was significantly lower, and ICT% and IRT% longer than in the other groups. LPS increased PIs, except in the intracranial arteries, which showed a decrease in PIs. In ductus venosus, PIVs were increased after LPS. LPS increased interleukin (IL)-6 in amniotic fluid and induced the expression of proinflammatory cytokines in placenta and fetal membranes, but not in lung. In fetal myocardium, TLR4 was constitutional. LPS induced the expression of IL-1beta and tumor necrosis factor (TNF)-alpha mRNA in myocardium, whereas inducible nitric oxide synthase (NOS2) protein and nitrotyrosine remained undetectable. CONCLUSIONS: As a response to endotoxin in amniotic fluid, fetal myocardium acutely generates cytokines and severe fetal cardiovascular compromise develops. These two may be linked through a mechanism that does not include NO.
BACKGROUND: Gene transfer into the amniotic fluid using recombinant adenovirus vectors was shown previously to result in high efficiency transfer of transgenes into the lungs and intestines. Adenovirus mediated in utero gene therapy, however, resulted in expression of the transgene for less than 30 days. Recombinant adenovirus associated viruses (rAAV) have the advantage of maintaining the viral genome in daughter cells thus providing for long-term expression of transgenes. METHODS: Recombinant AAV2 carrying green fluorescent protein (GFP) was introduced into the amniotic sac of fetal rodents and nonhuman primates. Transgene maintenance and expression was monitor. RESULTS: Gene transfer resulted in rapid uptake and long-term gene expression in mice, rats, and non-human primates. Expression and secretion of the reporter gene, GFP, was readily demonstrated within 72 hours post-therapy. In long-term studies in rats and nonhuman primates, maintenance of GFP DNA, protein expression, and reporter gene secretion was documented for over one year. CONCLUSIONS: Because only multipotential stem cells are present at the time of therapy, these data demonstrated that in utero gene transfer with AAV2 into stem cells resulted in long-term systemic expression of active transgene roducts. Thus, in utero gene transfer via the amniotic fluid may be useful in treatment of gene disorders.