β₃-Adrenoceptor Agonist Effects on the Urinary Bladder Beyond Detrusor Relaxation

Area of Science:

• Pharmacology
• Urology
• Cell Biology

Background:

• Beta3-adrenoceptor agonists (e.g., mirabegron, vibegron) achieve steady-state pharmacokinetics rapidly.
• Clinical improvements in overactive bladder (OAB) symptoms often extend beyond 4 weeks, suggesting mechanisms beyond simple detrusor muscle relaxation.

Purpose of the Study:

• To review mechanistic studies investigating the long-term effects of beta3-adrenoceptor agonists.
• To explore potential mechanisms contributing to OAB symptom improvement beyond initial detrusor smooth muscle relaxation.

Main Methods:

• Narrative review of existing literature.
• Analysis of studies involving prolonged administration of beta3-adrenoceptor agonists.

Main Results:

• Limited data suggests beta3-adrenoceptor agonists can reduce bladder fibrosis and hypertrophy.
• These agents may promote cell proliferation and normalize apoptosis and ferroptosis.
• Prolonged exposure may lead to partial desensitization of detrusor relaxation responses, potentially counteracting other effects.

Conclusions:

• Further long-term research is necessary to elucidate the role of these cellular processes in OAB symptom improvement.
• Clarifying the impact of potential desensitization is crucial for understanding the full clinical benefit of beta3-adrenoceptor agonists.