Abstract
In this study, the aim was to test the biochemical effects of melatonin supplementation in Intensive Care Unit (ICU) patients, since their blood levels are decreased. Sixty-four patients were enrolled in the study. From the evening of the 3rd ICU day, patients were randomized to receive oral melatonin (3 mg, group M) or placebo (group P) twice daily, at 20:00 and 24:00, until discharged. Blood was taken (at 00:00 and 14:00), on the 3rd ICU day to assess basal nocturnal melatonin values, and then during the treatment period on the 4th and 8th ICU days. Melatonin, total antioxidant capacity, and oxidative stress were evaluated in serum. Melatonin circadian rhythm before treatment was similar in the two groups, with a partial preservation of the cycle. Four hours from the 1st administration (4th ICU day, 00:00), melatonin levels increased to 2514 (982.3; 7148) pg·mL−1 in group M vs. 20.3 (14.7; 62.3) pg·mL−1 in group P (p < 0.001). After five treatment days (8th ICU day), melatonin absorption showed a repetitive trend in group M, while in group P nocturnal secretion (00:00) was impaired: 20 (11.5; 34.5) pg·mL−1 vs. 33.8 (25.0; 62.2) on the 3rd day (p = 0.029). Immediately from the beginning of treatment, the total antioxidant capacity was significantly higher in melatonin treated subjects at 00:00; a significant correlation was found between total antioxidant capacity and blood melatonin values (ρ = 0.328; p < 0.001). The proposed enteral administration protocol was adequate, even in the early phase, to enhance melatonin blood levels and to protect the patients from oxidative stress. The antioxidant effect of melatonin could play a meaningful role in the care and well-being of these patients.
Highlights
A high percentage of critically-ill patients suffer from an oxidative imbalance [1]
Melatonin is an indole amine with hypnotic, antioxidant [6], and antiseptic actions [7,8], and its endogenous levels exhibit a circadian rhythm
The aim of the present study is to describe circulating melatonin levels and their relationship with the biomarkers of oxidative stress, oxidant protection, inflammation, immune response [28,29], and apoptosis [30]
Summary
A high percentage of critically-ill patients suffer from an oxidative imbalance [1]. Guidelines suggest supplementation with vitamins, trace nutrients, and other antioxidants with the aim of restoring equilibrium [2]. ICU patients have wake-sleep rhythm disorders [3], possibly due to the low endogenous melatonin levels [4,5]. Endogenous melatonin concentrations are decreased in ICU patients, both in terms of night time peaks and in the basal diurnal levels [9]. It remains unknown if these low levels are due to a reduced endogenous production or a result of increased metabolism [10,11]. As examples, reduced melatonin levels are related to age, sepsis severity [14], post-traumatic stress disorder [15], and to the severity of sleep disruption during critical illness [10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
