La deficiencia de ácido fólico en la población venezolana: ¿un ejemplo de mala praxis en salud pública?

La evolución del proceso arteroesclerótico es el resultado de la conjunción multifactorial de factoresintrínsecos y extrínsecos. Este concepto deriva dela evidencia acumulada en los últimos 50 años,proveniente tanto de estudios experimentales comopoblacionales. Desde el punto de vista poblacional, sepuede considerar que el “Framingham Heart Study”,iniciado en 1948 bajo la dirección del Dr. ThomasDawber (1), ha sido y continua siendo el estudiomás relevante en la identificación de los factorescomunes que contribuyen al desarrollo a largo plazo,de enfermedad cardiovascular y/o cerebrovascular ensujetos aparentemente sanos

Effect of guggulsterone and cembranoids of Commiphora mukul on pancreatic phospholipase A2: Role in hypocholesterolemia

Guggulsterone (7) and cembranoids (8-12) from Commiphora mukul stem bark resin guggul were shown to be specific modulators of two independent sites that are also modulated by bile salts (1-6) to control cholesterol absorption and catabolism. Guggulsterone (7) antagonized the chenodeoxycholic acid (3)-activated nuclear farnesoid X receptor (FXR), which regulates cholesterol metabolism in the liver. The cembranoids did not show a noticeable effect on FXR, but lowered the cholate (1)-activated rate of human pancreatic IB phospholipase A2 (hPLA2), which controls gastrointestinal absorption of fat and cholesterol. Analysis of the data using a kinetic model has suggested an allosteric mechanism for the rate increase of hPLA2 by cholate and also for the rate-lowering effect by certain bile salts or cembranoids on the cholate-activated hPLA2 hydrolysis of phosphatidylcholine vesicles. The allosteric inhibition of PLA2 by certain bile salts and cembranoids showed some structural specificity. Biophysical studies also showed specific interaction of the bile salts with the interface-bound cholate-activated PLA2. Since cholesterol homeostasis in mammals is regulated by FXR in the liver for metabolism and by PLA2 in the intestine for absorption, modulation of PLA2 and FXR by bile acids and selected guggul components suggests novel possibilities for hypolipidemic and hypocholesterolemic therapies. © 2009 American Chemical Society and American Society of Pharmacognosy