Group V secreted phospholipase A2 plays a protective role against aortic dissection.

Aortic dissection is a life-threatening aortopathy involving separation of the aortic wall, whose underlying mechanisms are still incompletely understood. Epidemiological evidence suggests that unsaturated fatty acids improve cardiovascular health. Here, using quantitative RT-PCR, histological analyses, magnetic cell sorting and flow cytometry assays, and MS-based lipidomics, we show that the activity of a lipid-metabolizing enzyme, secreted phospholipase A2 group V (sPLA2-V), protects against aortic dissection by endogenously mobilizing vasoprotective lipids. Global and endothelial cell-specific sPLA2-V-deficient mice frequently developed aortic dissection shortly after infusion of angiotensin II (AT-II). We observed that in the AT-II-treated aorta, endothelial sPLA2-V mobilized oleic and linoleic acids, which attenuated endoplasmic reticulum stress, increased the expression of lysyl oxidase, and thereby stabilized the extracellular matrix in the aorta. Of note, dietary supplementation with oleic or linoleic acid reversed the increased susceptibility of sPLA2-V-deficient mice to aortic dissection. These findings reveal an unexplored functional link between sPLA2-driven phospholipid metabolism and aortic stability, possibly contributing to the development of improved diagnostic and/or therapeutic strategies for preventing aortic dissection.

Aortic Dissection and Cardiac Dysfunction Emerged Coincidentally During the Long-Term Treatment with Angiogenesis Inhibitors for Metastatic Renal Cell Carcinoma.

Angiogenesis inhibitors, such as sorafenib and axitinib, which target vascular endothelial growth factor (VEGF) signaling, are widely used for renal cell carcinoma, including metastasis. In this study, we report a case of cardiovascular adverse events of aortic dissection and cardiac dysfunction during treatment with sorafenib and axitinib for metastatic renal cell carcinoma. A 66-year-old man had been administered sorafenib for 2 years after nephrectomy due to renal cell carcinoma. To control the progression of metastatic lung tumor, axitinib was started after sorafenib for four years. During the treatment, angiotensin II type 1 receptor blockers and Ca antagonists were used to strictly control the axitinib-induced hypertension and proteinuria. Aortic dissection and cardiac dysfunction occurred coincidentally. Considering the critical role of VEGF signaling in the homeostasis of the cardiovascular system, we speculated that the long-term use of axitinib and sorafenib directly influenced the initiation of aortic dissection and cardiac dysfunction. Although the precise mechanisms underlying the aortic dissection and cardiac dysfunction induced by angiogenesis inhibition are still elusive, onco-cardiologists and oncologists should pay careful attention to cardiovascular toxicity and complications in patients with cancer, particularly patients undergoing long-term cancer treatment.

Translational Relevance and Recent Advances of Animal Models of Abdominal Aortic Aneurysm.

Human abdominal aortic aneurysm (AAA) pathophysiology is not yet completely understood. In conductance arteries, the insoluble extracellular matrix, synthesized by vascular smooth muscle cells, assumes the function of withstanding the intraluminal arterial blood pressure. Progressive loss of this function through extracellular matrix proteolysis is a main feature of AAAs. As most patients are now treated via endovascular approaches, surgical AAA specimens have become rare. Animal models provide valuable complementary insights into AAA pathophysiology. Current experimental AAA models involve induction of intraluminal dilation (nondissecting AAAs) or a contained intramural rupture (dissecting models). Although the ideal model should reproduce the histological characteristics and natural history of the human disease, none of the currently available animal models perfectly do so. Experimental models try to represent the main pathophysiological determinants of AAAs: genetic or acquired defects in extracellular matrix, loss of vascular smooth muscle cells, and innate or adaptive immune response. Nevertheless, most models are characterized by aneurysmal stabilization and healing after a few weeks because of cessation of the initial stimulus. Recent studies have focused on ways to optimize existing models to allow continuous aneurysmal growth. This review aims to discuss the relevance and recent advances of current animal AAA models. VISUAL OVERVIEW: An online visual overview is available for this article.

Acute aortic dissection in a patient receiving multiple tyrosine kinase inhibitors for 5 years.

A 48-year-old male presented with para-aortic lymph node metastases after surgical resection of a clear cell renal cell carcinoma. After first-line treatment with interferon alpha-2b, he was started on pazopanib and lapatinib. Blood pressure was well controlled with temocapril and amlodipine. Treatment had to be stopped 4 years and 8 months after initiation due to overt proteinuria. Then, sunitinib was started as third-line treatment. During the second cycle of sunitinib, he died due to a Stanford type A aortic dissection. Acute aortic dissection could be an adverse event associated with the long-term use of antiangiogenic tyrosine kinase inhibitors.