Antiremodeling Effect of Xanthine Oxidase Inhibition in a Canine Model of Atrial Fibrillation

Tomoharu Yoshizawa1,2, Shinichi Niwano1, Hiroe Niwano3

  • 1Department of Cardiovascular Medicine, Kitasato University School of Medicine.

Insights

Febuxostat, an antioxidant, suppressed atrial remodeling and reduced the inducibility of atrial fibrillation (AF) in canines. This suggests antioxidants may inhibit new-onset AF by mitigating oxidative stress and fibrosis.

Area of Science:

  • Cardiology
  • Pharmacology
  • Biochemistry

Background:

  • Atrial fibrillation (AF) is associated with increased reactive oxygen species (ROS) and cardiac remodeling.
  • Antioxidants are hypothesized to mitigate AF-related atrial remodeling.

Purpose of the Study:

  • To evaluate the effect of febuxostat, a xanthine oxidase (XO) inhibitor and antioxidant, on atrial remodeling in a canine model of AF.

Main Methods:

  • Rapid atrial pacing (400 bpm) for 3 weeks in dogs, divided into pacing + febuxostat, pacing control, and non-pacing groups.
  • Electrophysiological studies, Azan and immunofluorescent staining for fibronectin, and oxidative stress markers (DHE, FCF-DA) were used.

Main Results:

  • Febuxostat suppressed the shortening of the refractory period and reduced AF inducibility compared to controls (P=0.05).
  • Febuxostat inhibited atrial fibrosis, oxidative stress, and fibronectin expression in pacing-induced AF canines.

Conclusions:

  • The antioxidant properties of febuxostat may inhibit new-onset atrial fibrillation in canines.
  • Febuxostat demonstrates potential as a therapeutic agent for preventing AF progression by targeting oxidative stress and structural remodeling.

Related Concept Videos

Amyloid Fibrils03:03

Amyloid Fibrils

Amyloid fibrils are aggregates of misfolded proteins.  Under most circumstances, misfolded proteins are either refolded by chaperone proteins or degraded by the proteasome. However, in the case of a mutation or a disease, these proteins can accumulate to form large clusters and often further assemble to form elongated fibers, called fibrils. 
Amyloid deposits were observed as early as 1639 in the liver and the spleen.   In 1854, Rudolph Virchow performed iodine staining,...
12.0K
Amyloid Fibrils03:03

Amyloid Fibrils

6.4K
Feedback Inhibition00:46

Feedback Inhibition

Biochemical reactions are occurring constantly in cells, converting starting substances to different products, usually with the help of enzymes that speed the reactions. Without enzymes, it would take far too long for most reactions to occur to be useful to the cell!
57.2K
Fibril-associated Collagen01:11

Fibril-associated Collagen

Fibril-associated collagens are a type of collagens present in the extracellular matrix with interrupted triple helices or FACIT (Fibril-associated collagens interrupted triple-helices). FACIT help connect and attach the collagen fibrils with each other as well as with other proteins of the extracellular matrix.
For example, the type II collagen fibrils in cartilage have covalently bound type IX fibril-associated collagens at regular intervals. Other types of fibril-associated collagens are...
3.4K
Enzyme Inhibition01:30

Enzyme Inhibition

Inhibitors are molecules that reduce enzyme activity by binding to the enzyme. In a normally functioning cell, enzymes are regulated by a variety of inhibitors. Drugs and other toxins can also inhibit enzymes. Some inhibitors bind to the enzyme’s active site, while others inhibit enzymatic activity by binding to other sites on the protein structure.
92.5K
Inhibition of Cdk Activity02:34

Inhibition of Cdk Activity

The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...
6.0K