Low nocturnal melatonin secretion was associated with a greater mean arterial pressure increase during high-salt loading (15.2 vs 9.4 mmHg) in adults with metabolic syndrome and untreated hypertension.
Observational (n=130)
Is reduced night-time melatonin production associated with salt sensitivity and altered BP circadian rhythm in adults with metabolic syndrome and untreated hypertension?
Reduced night-time melatonin secretion is associated with increased salt sensitivity and non-dipping blood pressure patterns in adults with metabolic syndrome and untreated hypertension.
Absolute Event Rate: 15.2% vs 9.4%
Objective: Salt-sensitive hypertension is more common among metabolic syndrome (MetS) patients. However, the biological mechanisms behind this phenomenon remain poorly understood. Melatonin, a regulator of circadian rhythms and nocturnal blood pressure (BP) decline, may influence kidney sodium reabsorption and vascular tone. We aimed to determine whether reduced night-time melatonin production is related to salt sensitivity and BP circadian rhythm in adults with MetS. Design and method: We investigated 130 adults with MetS and untreated hypertension. All subjects were tested for salt sensitivity using a modified Sullivan protocol. BP circadian rhythm was assessed by 24-hour ambulatory blood pressure monitoring. Nocturnal melatonin secretion was estimated from the first morning urine using urinary 6-sulfatoxymelatonin (aMT6 s), normalized to creatinine (aMT6 s/Cr). Plasma renin activity, aldosterone, metabolic parameters, and renal function markers were also evaluated. Results: Salt sensitivity was present in 82 of 130 patients (63.1%). Patients with low urinary aMT6 s/Cr had a mean arterial pressure increase of 15.2 mmHg (SD 4.5) during the high-salt phase. Patients with higher aMT6 s/Cr levels had a mean arterial pressure increase of 9.4 mmHg (SD 3.7). Low aMT6 s/Cr levels were associated with more frequent non-dipping patterns and greater nighttime systolic load. In multivariate analysis, aMT6 s/Cr remained a significant predictor after adjustment for age, central obesity, metabolic parameters, aldosterone, and estimated glomerular filtration rate. Conclusions: Reduced night-time melatonin secretion appears to be an important biological factor contributing to salt-sensitive hypertension in MetS. Lower melatonin production may impair the circadian regulation of vascular tone and renal sodium handling, leading to non-dipping patterns and increased 24-hour BP load. Circadian biomarkers such as aMT6 s/Cr may improve risk stratification, and interventions aiming to restore melatonin rhythms could represent an additional strategy in the management of salt-sensitive hypertension in MetS.
أندروينكاشفيلي وآخرون (جمعة) أجروا دراسة رصدية في متلازمة الأيض وارتفاع ضغط الدم غير المعالج (n=130). تم تقييم إفراز الميلاتونين الليلي المنخفض مقابل الإفراز العالي للميلاتونين الليلي من حيث زيادة متوسط الضغط الشرياني خلال مرحلة الملح العالي. كان إفراز الميلاتونين الليلي المنخفض مرتبطًا بزيادة أكبر في متوسط الضغط الشرياني خلال تحميل الملح العالي (15.2 مقابل 9.4 مم زئبقي) لدى البالغين الذين يعانون من متلازمة الأيض وارتفاع ضغط الدم غير المعالج.