Plasma NOTCH3 and the risk of cardiovascular recurrence in patients with ischemic stroke.

BACKGROUND: Ischemic stroke patients are more prone to developing another cardiovascular event. AIM: This study aims to examine potential biological predispositions to cardiovascular recurrence in patients with ischemic stroke. DESIGN: Human and preclinical studies. METHODS: Quantitative proteomic analysis, animal stroke, atherosclerosis models and circulating endothelial cells (CECs) were employed to examine candidate biomarkers derived from an ischemic stroke cohort in Singapore. RESULTS: Proteomic analysis of pooled microvesicles of "Event" (n = 24) and without "Event" (n = 24) samples identified NOTCH3 as a candidate marker; plasma NOTCH3 were shown to be elevated in "Event" patients compared to those without "Events" and age-matched controls. In a validation cohort comprising 431 prospectively recruited ischemic stroke patients (mean age 59.1 years; median follow-up 3.5 years), men with plasma NOTCH3 (>1600pg/ml) harbored increased risk of cardiovascular recurrence (adjusted hazards ratio 2.29, 95% CI 1.10-4.77); no significant association was observed in women. Chronic renal failure, peripheral artery disease and NT-pro-brain natriuretic peptide were significant predictors of plasma NOTCH3 in men without ischemic stroke (adjusted r2=0.43). Following middle cerebral artery occlusion, NOTCH3 expression in mouse sera increased and peaked at 24 hrs, persisting thereafter for at least 72 hours. In Apoe-/- atherosclerotic mice, NOTCH3 stained the endothelium of defective arterial lining and atherosclerotic plaques. Analysis of CECs isolated from stroke patients revealed increased gene expression of NOTCH3, further supporting endothelial damage underpinning NOTCH3-mediated atherosclerosis. CONCLUSION: Findings from this study suggests that NOTCH3 could be important in cardiovascular recurrence following an ischemic stroke.

Multiple aspects of lymphatic dysfunction in an ApoE -/- mouse model of hypercholesterolemia.

Introduction: Rodent models of cardiovascular disease have uncovered various types of lymphatic vessel dysfunction that occur in association with atherosclerosis, type II diabetes and obesity. Previously, we presented in vivo evidence for impaired lymphatic drainage in apolipoprotein E null (ApoE -/- ) mice fed a high fat diet (HFD). Whether this impairment relates to the dysfunction of collecting lymphatics remains an open question. The ApoE -/- mouse is a well-established model of cardiovascular disease, in which a diet rich in fat and cholesterol on an ApoE deficient background accelerates the development of hypercholesteremia, atherosclerotic plaques and inflammation of the skin and other tissues. Here, we investigated various aspects of lymphatic function using ex vivo tests of collecting lymphatic vessels from ApoE +/+ or ApoE -/- mice fed a HFD. Methods: Popliteal collectors were excised from either strain and studied under defined conditions in which we could quantify changes in lymphatic contractile strength, lymph pump output, secondary valve function, and collecting vessel permeability. Results: Our results show that all these aspects of lymphatic vessel function are altered in deleterious ways in this model of hypercholesterolemia. Discussion: These findings extend previous in vivo observations suggesting significant dysfunction of lymphatic endothelial cells and smooth muscle cells from collecting vessels in association with a HFD on an ApoE-deficient background. An implication of our study is that collecting vessel dysfunction in this context may negatively impact the removal of cholesterol by the lymphatic system from the skin and the arterial wall and thereby exacerbate the progression and/or severity of atherosclerosis and associated inflammation.

Lymphadenectomy promotes tumor growth and cancer cell dissemination in the spontaneous RET mouse model of human uveal melanoma.

Resection of infiltrated tumor-draining lymph nodes (TDLNs) is a standard practice for the treatment of several cancers including breast cancer and melanoma. However, many randomized prospective trials have failed to show convincing clinical benefits associated with LN removal and the role of TDLNs in cancer dissemination is poorly understood. Here, we found in a well-characterized spontaneous mouse model of uveal melanoma that the growth of the primary tumor was accompanied by increased lymphangiogenesis and cancer cell colonization in the LNs draining the eyes. But, unexpectedly, early resection of the TDLNs increased the growth of the primary tumor and associated blood vessels as well as promoted cancer cell survival and dissemination. These effects were accompanied by increased tumor cell proliferation and expression of phosphorylated AKT. Topical application of a broad anti-inflammatory agent, Tobradex, or an oral treatment with cyclooxygenase-2 specific inhibitor, Celecoxib, reversed tumor progression observed after complete lymphadenectomy. Our study confirms the importance of tumor homeostasis in cancer progression by showing the enhancing effects of TDLN removal on tumor growth and cancer cell dissemination, and suggests that TDLN resection may only be beneficial if used in combination with anti-inflammatory drugs such as Tobradex and Celecoxib.