Mary C. Zuniga

Eotaxin Augments Calcification in Vascular Smooth Muscle Cells

Calcification of atherosclerotic plaques in elderly patients represents a potent risk marker of cardiovascular events. Plasma analyses of patients with or without calcified plaques reveal significant differences in chemokines, particularly eotaxin, which escalates with increased calcification. We therefore, hypothesize that eotaxin in circulation augments calcification of vascular smooth muscle cells (VSMCs) possibly via oxidative stress in the vasculature. We observe that eotaxin increases the rate of calcification significantly in VSMCs as evidenced by increased alkaline phosphatase activity, calcium deposition, and osteogenic marker expression. In addition, eotaxin promotes proliferation in VSMCs and triggers oxidative stress in a NADPH oxidase dependent manner. These primary novel observations support our proposition that in the vasculature eotaxin augments mineralization. Our findings suggest that eotaxin may represent a potential therapeutic target for prevention of cardiovascular complications in the elderly. J. Cell. Biochem. 118: 647–654, 2017.

Physiologic levels of resistin induce a shift from proliferation to apoptosis in macrophage and VSMC co-culture

Background. Resistin, an adipokine with inflammatory properties, has been associated with plaque vulnerability. Vascular smooth muscle cells and macrophages are the major cellular components in advanced atherosclerotic plaques and interdependently affect plaque stability. The purpose of this study was to examine the effects of resistin on the interactions of vascular smooth muscle cells and macrophages using co‐culture systems. Methods. Human monocytes were differentiated into macrophages. Vascular smooth muscle cells were grown and starved prior to co‐culture condition. Indirect co‐culture was performed by treating macrophages with resistin at 10 ng/mL for 24 hours with/without &egr;V1–2, a selective protein kinase C epsilon inhibitor. Macrophages supernatants were then used to treat vascular smooth muscle cells for 24 hours. Direct co‐culture was performed by culturing macrophages and vascular smooth muscle cells together for 24 to 48 hours. Cultures were evaluated for changes in proliferation, apoptosis, and gene expression of apoptosis, proliferation, and inflammation‐associated genes. Results. Macrophages induced vascular smooth muscle cells proliferation, which was further exaggerated in resistin‐treated macrophages in the indirect co‐culture model. Resistin also upregulated cyclin D1 and proliferating cell nuclear antigen via protein kinase C epsilon in the indirect co‐culture. Augmented proliferation was further confirmed in the direct co‐culture model, particularly at increased macrophage ratios. However, resistin treatment induced apoptosis in the presence of direct cell to cell interactions. Along with the shift to apoptosis, expressions of caspase 3 and caspase 8 were upregulated. The expression of kappa‐light‐chain‐enhancer of activated B cells 1 and 2 was similar in direct and indirect co‐cultures. Conclusion. Resistin promotes a shift from proliferation to apoptosis in vascular smooth muscle cells and macrophage co‐culture systems with cellular composition similar to that found in vulnerable regions of plaques. Protein kinase C epsilon mediates the effects of resistin, suggesting that protein kinase C epsilon may represent a therapeutic strategy in resistin‐associated atherosclerotic complications.

A Prospective Evaluation of Systemic Biomarkers and Cognitive Function Associated with Carotid Revascularization.

Objective: To determine factors affecting cognition and identify predictors of long-term cognitive impairment following carotid revascularization procedures. Background: Cognitive impairment is common in older patients with carotid occlusive diseases. Methods: Patients undergoing carotid intervention for severe occlusive diseases were prospectively recruited. Patients received neurocognitive testing before, 1, and 6 months after carotid interventions. Plasma samples were also collected within 24 hours after carotid intervention and inflammatory cytokines were analyzed. Univariate and multivariate logistic regressions were performed to identify risk factors associated with significant cognitive deterioration (>10% decline). Results: A total of 98 patients (48% symptomatic) were recruited, including 55 patients receiving carotid stenting and 43 receiving endarterectomy. Mean age was 69 (range 54–91 years). Patients had overall improvement in cognitive measures 1 month after revascularization. When compared with carotid stenting, endarterectomy patients demonstrated postoperative improvement in cognition at 1 and 6 months compared with baseline. Carotid stenting (odds ratio 6.49, P = 0.020) and age greater than 80 years (odds ratio 12.6, P = 0.023) were associated with a significant long-term cognitive impairment. Multiple inflammatory cytokines also showed significant changes after revascularization. On multivariate analysis, after controlling for procedure and age, IL-12p40 (P = 0.041) was associated with a higher risk of significant cognitive impairment at 1 month; SDF1-&agr; (P = 0.004) and tumor necrosis factor alpha (P = 0.006) were independent predictors of cognitive impairment, whereas interleukin-6 (P = 0.019) demonstrated cognitive protective effects at 6 months after revascularization. Conclusions: Carotid interventions affect cognitive function. Systemic biomarkers can be used to identify patients at risk of significant cognitive decline postprocedures that benefit from targeted cognitive training.