Pretreatment by low-dose fibrates protects against acute free fatty acid-induced renal tubule toxicity by counteracting PPAR? deterioration.

ABSTRACT: Development of a preventive strategy against tubular damage associated with proteinuria is of great importance. Recently, free fatty acid (FFA) toxicities accompanying proteinuria were found to be a main cause of tubular damage, which was aggravated by insufficiency of peroxisome proliferator-activated receptor alpha (PPAR?), suggesting the benefit of PPAR? activation. However, an earlier study using a murine acute tubular injury model, FFA-overload nephropathy, demonstrated that high-dose treatment of PPAR? agonist (0.5% clofibrate diet) aggravated the tubular damage as a consequence of excess serum accumulation of clofibrate metabolites due to decreased kidney elimination. To induce the renoprotective effects of PPAR? agonists without drug accumulation, we tried a pretreatment study using low-dose clofibrate (0.1% clofibrate diet) using the same murine model. Low-dose clofibrate pretreatment prevented acute tubular injuries without accumulation of its metabolites. The tubular protective effects appeared to be associated with the counteraction of PPAR? deterioration, resulting in the decrease of FFAs influx to the kidney, maintenance of fatty acid oxidation, diminution of intracellular accumulation of undigested FFAs, and attenuation of disease developmental factors including oxidative stress, apoptosis, and NF?B activation. These effects are common to other fibrates and dependent on PPAR? function. Interestingly, however, clofibrate pretreatment also exerted PPAR?-independent tubular toxicities in PPAR?-null mice with FFA-overload nephropathy. The favorable properties of fibrates are evident when PPAR?-dependent tubular protective effects outweigh their PPAR?-independent tubular toxicities. This delicate balance seems to be easily affected by the drug dose. It will be important to establish the appropriate dosage of fibrates for treatment against kidney disease and to develop a novel PPAR? activator that has a steady serum concentration regardless of kidney dysfunction.

SUBMITTER: Takahashi K 

PROVIDER: S-EPMC6300991 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature