Sphingosine kinase 1 (SphK1) phosphorylates sphingosine to form sphingosine-1-phosphate (S1P) and is a critical regulator of sphingolipid-mediated functions. Cell-based studies suggest a tumor-promoting function for the SphK1/S1P pathway. Also, our previous studies implicated the SphK1/S1P pathway in the induction of the arachidonic acid cascade, a major inflammatory pathway involved in colon carcinogenesis. Therefore, we investigated whether the SphK1/S1P pathway is necessary for mediating carcinogenesis in vivo. Here, we report that 89% (42/47) of human colon cancer samples stained positively for SphK1, whereas normal colon mucosa had negative or weak staining. Adenomas had higher expression of SphK1 vs. normal mucosa, and colon cancers with metastasis had higher expression of SphK1 than those without metastasis. In the azoxymethane (AOM) murine model of colon cancer, SphK1 and S1P were significantly elevated in colon cancer tissues compared to normal mucosa. Moreover, blood levels of S1P were higher in mice with colon cancers than in those without cancers. Notably, SphK1(-/-) mice subjected to AOM had significantly less aberrant crypt foci (ACF) formation and significantly reduced colon cancer development. These results are the first in vivo evidence that the SphK1/S1P pathway contributes to colon carcinogenesis and that inhibition of this pathway is a potential target for chemoprevention.

Decreased PV velocity is associated with increased risk of future PVT. Patients with cirrhosis and decreased PV velocity are a high-risk subgroup that warrants further investigation with prospective study.

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Transcaval aortic access has been used for deployment of transcatheter aortic valves in patients in whom conventional arterial approaches are not feasible. The present report describes its use for thoracic endovascular aortic repair (TEVAR) in a 61-year-old man with a descending thoracic aneurysm. Transcaval access was performed in lieu of a surgical iliac conduit in view of small atherosclerotic pelvic arteries. TEVAR was successfully performed, followed by intervascular tract occlusion with the use of a ventricular septal occluder. Computed tomography 2 d later demonstrated no extravasation. At 1 mo, the aneurysm was free of endoleaks, the aortocaval tract had healed, and the patient had returned to baseline functional status.

No abstract