Washington: Obesity suppresses an important cellular process that is capable of preventing kidney cell damage, a new study has revealed.
Obesity increases a chronic kidney disease patient's risk of developing kidney failure, but the mechanism underlying this connection has remained unclear.
Kosuke Yamahara, Takashi Uzu, MD, PhD (Shiga University of Medical Science, in Japan), and their colleagues suspected that decreased functioning of a process called autophagy might play a role.
Autophagy is a degradation system within cells that removes damaged proteins and other defective cellular components, and autophagy insufficiency is common in obese individuals.
The researchers found that in normal-weight mice with kidney disease, autophagy was active in kidney cells.
However, in obese mice with kidney disease, autophagy was suppressed and kidney cells became damaged. Normal-weight mice with kidney disease and defective autophagy (due to a gene deletion) also experienced kidney cell damage.
The investigators also discovered that a potent suppressor of autophagy (called mTOR) was hyperactivated in the kidneys of obese mice, and treatment with an mTOR inhibitor ameliorated autophagy insufficiency. Furthermore, both mTOR hyperactivation and autophagy suppression were observed in kidney specimens from obese patients with kidney disease.
The study has been published in the upcoming issue of the Journal of the American Society of Nephrology (JASN).