RESUMO
Aortic aneurysms (AAs) are pathological dilatations of the aorta. Pathogenic variants in genes encoding for proteins of the contractile machinery of vascular smooth muscle cells (VSMCs), genes encoding proteins of the transforming growth factor beta signaling pathway and extracellular matrix (ECM) homeostasis play a role in the weakening of the aortic wall. These variants affect the functioning of VSMC, the predominant cell type in the aorta. Many variants have unknown clinical significance, with unknown consequences on VSMC function and AA development. Our goal was to develop functional assays that show the effects of pathogenic variants in aneurysm-related genes. We used a previously developed fibroblast transdifferentiation protocol to induce VSMC-like cells, which are used for all assays. We compared transdifferentiated VSMC-like cells of patients with a pathogenic variant in genes encoding for components of VSMC contraction (ACTA2, MYH11), transforming growth factor beta (TGFß) signaling (SMAD3) and a dominant negative (DN) and two haploinsufficient variants in the ECM elastic laminae (FBN1) to those of healthy controls. The transdifferentiation efficiency, structural integrity of the cytoskeleton, TGFß signaling profile, migration velocity and maximum contraction were measured. Transdifferentiation efficiency was strongly reduced in SMAD3 and FBN1 DN patients. ACTA2 and FBN1 DN cells showed a decrease in SMAD2 phosphorylation. Migration velocity was impaired for ACTA2 and MYH11 cells. ACTA2 cells showed reduced contractility. In conclusion, these assays for showing effects of pathogenic variants may be promising tools to help reclassification of variants of unknown clinical significance in AA-related genes.
Assuntos
Actinas/genética , Aneurisma Aórtico/etiologia , Fibrilina-1/genética , Cadeias Pesadas de Miosina/genética , Proteína Smad3/genética , Aneurisma Aórtico/metabolismo , Aneurisma Aórtico/patologia , Diferenciação Celular/genética , Transdiferenciação Celular/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Modelos Biológicos , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/citologia , Miócitos de Músculo Liso/metabolismo , Proteína Smad2/metabolismoRESUMO
Ischemic colitis is a serious complication of aortic surgery. The condition continues to be difficult to diagnose at an early stage. This study monitors the biochemical changes in systemic and selective inferior mesenteric vein (IMV) blood sampling during aortic surgery and compares the reproducibility of this method to intraoperative colonic pulse oximetry in a series of 18 patients undergoing infrarenal aortic aneurysm repair. Base excess, pH, pCO2, and lactate were altered by aortic cross-clamping but returned to normal within 48 hr. IMV inorganic phosphate levels were higher than systemic values, suggesting improved sensitivity with selective sampling. BB isoenzymes of creatine kinase remained normal in all patients. Pulse oximetry signals were inconsistently obtained from the colon. This study establishes the physiological changes in IMV biochemistry during aortic surgery. Unlike intraoperative pulse oximetry, selective IMV sampling provides reproducible measurements of colonic perfusion. This simple and safe technique warrants further assessment of its accuracy at diagnosing ischemic colitis.