In chronic kidney disease altered cardiac metabolism precedes cardiac hypertrophy

Area of Science:

• Nephrology
• Cardiology
• Mitochondrial Biology

Background:

• Conduit arterial disease is a known contributor to cardiac complications in chronic kidney disease (CKD).
• Cardiac function in CKD patients without arterial disease has not been previously investigated.
• Understanding direct CKD effects on the heart is crucial for developing targeted therapies.

Purpose of the Study:

• To investigate cardiac function in a CKD model lacking conduit arterial disease.
• To determine if CKD directly impacts cardiac mitochondrial respiration.
• To explore the role of activin A signaling in CKD-induced cardiac changes.

Main Methods:

• Utilized an Alport syndrome mouse model bred to lack conduit arterial disease, exhibiting CKD stage 4-5.
• Performed cardiac tissue respirometry (Oroboros) to assess mitochondrial oxygen flux.
• Conducted RNA-Seq analysis of cardiac tissue to identify gene expression changes.
• Administered activin A antibody treatment to assess its impact on cardiac and skeletal changes.

Main Results:

• CKD mice showed significantly diminished ADP-stimulated cardiac oxygen flux, indicating impaired mitochondrial respiration.
• RNA-Seq revealed decreased expression of cardiac mitochondrial oxidative phosphorylation genes in CKD mice.
• Activin A antibody treatment did not improve cardiac function but affected skeletal remodeling.

Conclusions:

• CKD directly impairs cardiac mitochondrial respiration and oxidative phosphorylation, independent of arterial disease.
• This study provides the first evidence of CKD directly affecting cardiac respiration.
• Targeting cardiac oxidative phosphorylation may represent a novel therapeutic strategy for CKD-related heart disease.