Melatonin Therapy Improves Cardiac Autonomic Modulation in Pinealectomized Patients.

Area of Science:

• Cardiology
• Endocrinology
• Sleep Medicine

Background:

• Pinealectomy eliminates endogenous melatonin production.
• Melatonin plays a role in regulating autonomic nervous system function.
• Cardiac autonomic modulation is crucial for cardiovascular health.

Purpose of the Study:

• To investigate the impact of melatonin replacement therapy on cardiac autonomic modulation.
• To assess changes in heart rate variability (HRV) in pinealectomized patients receiving melatonin.
• To evaluate the reversibility of these effects after melatonin discontinuation.

Main Methods:

• Open-label, single-arm, proof-of-concept study.
• Inclusion of 5 pinealectomized patients with confirmed melatonin absence.
• Melatonin (3 mg/day) administered for 3 months, followed by a 6-month washout period.
• Cardiac autonomic function assessed via HRV during polysomnography.

Main Results:

• Melatonin treatment significantly increased vagal HRV indices (RMSSD, pNN50, HF power).
• Sympathetic HRV indices (SDNN, LF power) also showed significant increases.
• These HRV improvements reverted to baseline levels after discontinuing melatonin.
• HRV entropy-based regularity parameters remained unchanged.

Conclusions:

• Melatonin replacement therapy may improve cardiac autonomic modulation in melatonin-deficient individuals.
• The observed improvements in HRV are dependent on continued melatonin treatment.
• Further research is warranted to explore the long-term cardiovascular implications.