ABSTRACT
Inhibition of CD36, a fatty acid transporter, has been reported to prevent glucotoxicity and ameliorate high glucose induced beta cell dysfunction. Ezetimibe is a selective cholesterol absorption inhibitor that blocks Niemann Pick C1-like 1 protein, but may exert its effect through suppression of CD36. We attempted to clarify the beneficial effect of ezetimibe on insulin secreting cells and to determine whether this effect is related to change of CD36 expression. mRNA expression of insulin and CD36, intracellular peroxide level and glucose stimulated insulin secretion (GSIS) under normal (5.6 mM) or high glucose (30 mM) condition in INS-1 cells and primary rat islet cells were compared. Changes of the aforementioned factors with treatment with ezetimibe (20 μM) under normal or high glucose condition were also assessed. mRNA expression of insulin was decreased with high glucose, which was reversed by ezetimibe in both INS-1 cells and primary rat islets. CD36 mRNA expression was increased with high glucose, but decreased by ezetimibe in INS-1 cells and primary rat islets. Three-day treatment with high glucose resulted in an increase in intracellular peroxide level; however, it was decreased by treatment with ezetimibe. Decrease in GSIS by three-day treatment with high glucose was reversed by ezetimibe. Palmitate uptake following exposure to high glucose conditions for three days was significantly elevated, which was reversed by ezetimibe in INS-1 cells. Ezetimibe may prevent glucotoxicity in pancreatic β-cells through a decrease in fatty acid influx via inhibition of CD36.
Subject(s)
Animals , Male , Rats , Anticholesteremic Agents/pharmacology , CD36 Antigens/antagonists & inhibitors , Cells, Cultured , Ezetimibe/pharmacology , Flow Cytometry , Glucose/toxicity , Insulin/genetics , Insulin-Secreting Cells/cytology , Palmitic Acid/metabolism , RNA, Messenger/metabolism , Rats, Sprague-Dawley , Reactive Oxygen Species/metabolism , Real-Time Polymerase Chain ReactionABSTRACT
En los últimos años han surgido algunas investigaciones y guías de práctica clínica relacionadas con el diagnóstico y tratamiento de las dislipidemias, que aportaron nuevos conocimientos (y controversias) sobre dicha problemática. En este resumen se describen, en primer lugar, las características de las "nuevas guías" norteamericanas para el manejo del colesterol publicadas a fines de 2013 y se comparan con las recomendaciones tradicionales. En segundo lugar, se analizan los últimos estudios que evaluaron el impacto cardiovascular de otros fármacos hipolipemiantes (ezetimibe y ácido nicotínico) en pacientes en prevención secundaria tratados con estatinas. Finalmente, se mencionan las nuevas drogas hipolipemiantes desarrolladas en los últimos años, como el lomitapide, el mipomersen y los inhibidores de la PCSK9, y se comentan el mecanismo de acción, su eficacia, sus efectos colaterales y los escenarios clínicos en donde podrían utilizarse. (AU)
In recent years, some research and clinical practice guidelines related to the diagnosis and treatment of dyslipidemia, which provided new knowledge (and controversy) about this problem have emerged. In this review, the characteristics of the American "new guidelines" for cholesterol management published by the end of 2013 are described, and they are compared with the traditional recommendations. In addition, recent studies assessing the cardiovascular impact of other lipid-lowering drugs (ezetimibe and nicotinic acid) in patients in secondary prevention treated with statins are analyzed. Finally, new hypolipidemic drugs developed in recent years are mentioned (lomitapide, mipomersen and PCSK9 inhibitors), discussing the mechanism of action, efficacy, side effects and clinical settings where they could be used. (AU)