The over-arching hypothesis to be tested in this research is that vascular inflammation due to neutrophil infiltration is critical to the pathophysiology of preeclampsia. Neutrophils infiltrating the vasculature could cause inflammation and vasoconstriction by release of toxic compounds, such as reactive oxygen species (ROS), TNF??and thromboxane.
In Specific Aim 1, we will determine if maternal vascular infiltration by neutrophils is a hallmark of preeclampsia, and associated with vascular inflammation. Subcutaneous fat, omental fat and placental tissue from pregnant patients will be collected and evaluated by immunohisto chemistry to assess vascular phenotypes of normal nonpregnant, normal pregnant and preeclamptic women, and to determine if neutrophil infiltration is restricted to the maternal compartment. We will stain tissues for CD66b (a neutrophil marker), intercellular adhesion molecule-1 (an endothelial adhesion molecule for neutrophils), interleukin-8 (IL-8, a potent neutrophil chemokine), NF-?B and COX-2 (hallmarks of inflammation), myeloperoxidase (a potent oxidizing enzyme), and matrix metalloproteinases 1 and 8. The in situ findings of vascular pathology observed in this Aim will drive the mechanistic studies of Aims 2-4 which will examine mechanisms for neutrophil induced vascular inflammation and vasoconstriction.
In Specific Aim 2, we will evaluate whether neutrophils that have infiltrated into the intimal space could be responsible for transmitting inflammation to the vascular smooth muscle by co-culturing neutrophils with human vascular smooth cells. We will use transfection and cell culture to determine if neutrophils can activate NF-?B and induce expression of COX-2, IL-8 and thromboxane in human vascular smooth muscle cells (VSMC).
In Specific Aim 3, we will use a myograph system with isolated omental vessels and cell culture of VSMC to examine cellular mechanisms whereby neutrophils could cause vasoconstriction and/or enhance vessel reactivity to vasoconstrictors.
In Specific Aim 4, we will determine if neutrophils or neutrophil products induce epigenetic changes in vascular smooth muscle genes related to inflammation, and thus, may program adverse long-term effects on maternal cardiovascular function. Methylation patterns of candidate genes will be evaluated in vessels from women with normal pregnancies and women with preeclampsia by bisulfite DNA sequence analysis and COBRA (Combined Bisulfite Restriction Analysis). We will also determine if neutrophils or neutrophil products (ROS, TNF?) alter the methylation status of these genes in a similar pattern in cultured VSMC. This novel hypothesis may explain future health issues, including recurrent preeclampsia and future risk of cardiovascular disease.
Preeclampsia is a leading cause of maternal and fetal morbidity and mortality. This research will test the hypothesis that vascular inflammation due to neutrophil infiltration is critical to the pathophysiology of preeclampsia. This hypothesis encompasses molecular explanations for a vicious cycle that reinforces vascular inflammation in preeclampsia, and creates an epigenetic imprint in the maternal vascular system that may predispose women to chronic cardiovascular disease.
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