Obesity suppresses cellular process critical to kidney health

Obesity increases a chronic kidney disease patient's risk of developing kidney failure.

Obesity suppresses an important cellular process that prevents kidney cell damage, according to a study appearing in an upcoming issue of the Journal of the American Society of Nephrology (JASN). The findings suggest that restoring the process could protect the kidney health of obese individuals.

Obesity increases a chronic patient's risk of developing , 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 . 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.

"Obesity suppresses autophagy via an abnormal activation of nutrition sensing signals in the kidney," said Yamahara. "Our results suggest that restoring the kidney-protective action of may improve the health of obese patients."

In an accompanying editorial, Ken Inoki, PhD (University of Michigan) stated that "the results of this study provide an important pathomechanism underlying obesity-associated renal… cell damage."

More information: The article, entitled "Obesity-mediated Autophagy Insufficiency Exacerbates Proteinuria-induced Tubulointerstitial Lesions," will appear online on October 3, 2013, DOI: 10.1681/ASN.2012111080

The editorial, entitled "Proximal Tubules Forget 'Self-Eating' When They Meet Western Meals," will appear online on October 3, 2013, DOI: 10.1681/ASN.2013070794

Related Stories

Recommended for you

Score IDs patients with upper extremity DVT at low risk

date 54 minutes ago

(HealthDay)—For patients with upper-extremity deep vein thrombosis (DVT), six easily available factors can be used to create a score that identifies those at low risk of adverse events during the first ...

Combined drug treatment combats kidney disease

date 11 hours ago

A recent discovery by drug researchers whereby coupling specific cell membrane receptors has altered kidney cell function has triggered a re-think of how to treat chronic kidney disease (CKD) more effectively.

Active substance targeting dreaded hospital germs

date 11 hours ago

In the German Center for Infection Research (DZIF), scientists have conducted clinical studies on an active substance against the dreaded hospital pathogen Staphylococcus aureus: a highly effective protein from bacteriophages ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.