Objective: Persistent inflammation and oxidative stress influence the progression of diabetic nephropathy. Metalloproteinases (MMPs) participate in extracellular matrix remodeling. Statins show favorable anti-inflammatory effects in chronic kidney disease. We evaluated the effect of rosuvastatin on inflammatory and pro-fibrotic responses due to exposure to different glucose or free fatty acid (FFA) concentrations.
Methods: Human mesangial cells (HMCs) grown at 5.5 (normal glucose) or 22 mmol/l (high glucose) glucose or exposed to FFA were treated with angiotensin-II in the presence or absence of rosuvastatin. We measured MMP-2, MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), and TIMP-2 expression and activity, and quantified the fibrotic factors transforming growth factor-β1 (TGF-β1), fibronectin, and collagen IV.
Results: At normal glucose, angiotensin-II induced a dose-dependent downregulation of MMP-2; rosuvastatin reversed this effect. On the contrary, TIMP-2 and MMP-9 were upregulated by angiotensin-II and downregulated by rosuvastatin; the effects on TIMP-1 were negligible. Some of the angiotensin-II effects were potentiated in the presence of high glucose and FFA; under both conditions, rosuvastatin was able to reverse these effects. MMP-2 and MMP-9 activity followed the same trend of expression, with rosuvastatin able to upregulate MMP-2 activity. The modulation of the MMP/TIMP system was paralleled by an increase in TGF-β1, fibronectin, and collagen-IV; all were reduced by rosuvastatin treatment. Silencing the MMP-2 gene confirmed its role in modulating some of these angiotensin-II effects.
Conclusion: Angiotensin-II induces a pro-fibrotic response in HMCs mainly via a dysregulation of the MMP-2/TIMP-2 pattern. This effect, partially amplified in the presence of high glucose and FFA, is reversed by rosuvastatin, suggesting another potential therapeutic application for this 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor.