Statin Modulation of Human T-Cell Proliferation, IL-1ß and IL-17 Production, and IFN-γ T Cell Expression: Synergy with Conventional Immunosuppressive Agents.

HMG-CoA reductase inhibitors (statins) have been demonstrated to be immunomodulatory for human immune-mediated disease and in experimental models. The aim of this study was to compare statin-mediated immunosuppressive effects on human T-cell responses in vitro with those of conventional immunosuppressives (dexamethasone, cyclosporin A (CsA), mycophenolate, and rapamycin). Statins (atorvastatin, lovastatin, and simvastatin) were investigated for their modulatory effects on human PBMC viability, cytokine profiles, and T-cell proliferation. At concentrations that inhibited anti-CD3/28-stimulated T-cell proliferation (P < 0.01), simvastatin significantly decreased intracellular CD4(+) T-cell expression of IFN-γ (P < 0.01) to levels similar to those induced by conventional immunosuppressives. Atorvastatin and lovastatin also decreased IFN-γ expression, although to a lesser degree (P < 0.05). All three statins reduced levels of IL-17 production (P < 0.01). However, in response to anti-CD3/28 stimulation, simvastatin significantly upregulated IL-1ß production (P < 0.05). The profile of cytokines produced in response to anti-CD3/28 stimulation was similar when both atorvastatin and dexamethasone were added as compared with dexamethasone alone, suggesting that atorvastatin can synergise with dexamethasone with respect to immunomodulation of cytokines. This data supports the hypothesis of selective statin-mediated immunomodulatory effects on human immune cells.

Comparative effects of fatty acids on endothelial inflammatory gene expression.

BACKGROUND: Endothelial dysfunction may be related to adverse effects of some dietary fatty acids (FAs). Although in vitro studies have failed to show consistent findings, this may reflect the diverse experimental protocols employed and the limited range of FAs and end points studied. AIMS: To investigate the effect of dietary FA type (saturated, monounsaturated, n-6 and n-3 polyunsaturated fatty acids), concentration, incubation time and cell stimulation state, on a broad spectrum of endothelial inflammatory gene expression. METHODS: Using human umbilical vein endothelial cells, with and without stimulation (+/-10 ng/ml TNFalpha), the effects of arachidonic (AA), docosahexaenoic (DHA), eicosapentaenoic (EPA), linoleic (LA), oleic (OA) and palmitic acids (PA) (10, 25 and 100 microM), on the expression of genes encoding a number of inflammatory proteins and transcription factors were assessed by quantitative real time RT-PCR. RESULTS: Individual FAs differentially affect endothelial inflammatory gene expression in a gene-specific manner. EPA, LA and OA significantly up-regulated MCP-1 gene expression compared to AA (p = 0.001, 0.013, 0.008, respectively) and DHA (p < 0.0005, = 0.004, 0.002, respectively). Furthermore, cell stimulation state and FA incubation time significantly influenced reported FA effects on gene expression. CONCLUSION: The comparative effects of saturated, monounsaturated, n-6 and n-3 polyunsaturated FAs on endothelial gene expression depend on the specific FA investigated, its length of incubation, cell stimulation state and the gene investigated. These findings may explain existing disparity in the literature.