ADHD, one of the most prevalent diseases during childhood, we still do not know its precisely origin, although oxidative/nitrosative stress and the hypothalamic-pituitary-adrenal axis are suggested contributors. Methylphenidate, among others, is the main drug used in these patients, but its effects on relevant markers and structures remain unclear. This study, involving 59 patients diagnosed with ADHD according to DSM-5 criteria, aimed to assess changes in cortisol levels (using cortisol awakening response, CAR) and oxidative/nitrosative status with the treatment. Blood samples before and 3 months after treatment with methylphenidate were used to measure oxidative and inflammatory markers, and the endogenous antioxidant activity, while saliva samples tracked cortisol awakening response (CAR). The results show a treatment-related improvement in the redox profile, with the reduction of advanced oxidation protein products (AOPP), lipid peroxidation (LPO), and nitrite plus nitrate (NOx) levels, and the increase of the enzymatic activities of glutathione reductase (GRd) and catalase (CAT). Moreover, the area under the curve (AUC) of CAR increased significantly, indicating increased reactivity of the HPA axis. These result support by the first time the involvement of the endogenous antioxidant system in the pathophysiology of ADHD.

Objective. To evaluate serum neuronal and inflammatory biomarkers in asphyctic newborns treated with hypothermia alone or hypothermia plus melatonin, and whether biomarkers correlate with neurodevelopmental outcomes. Design. This is a pilot multicentre, randomised, controlled, double blind clinical trial. Neuronal glial fibrillary acidic protein (GFAP), granulocyte-macrophage colony-stimulating factor (GM-CSF), and inflammatory cytokines (interleukin (IL)-1, IL-2, IL-7 and IL-13) were measured in serum samples at hospital admission (T0), 24 hours (T1), 72 hours (T2) and 7-10 days of age (T3). Neurodevelopmental outcomes (Bayley Scales of Infant and Toddler Development-III scales, Gross Motor Function Classification System (GMFCS) and the Tardieu scale) were performed at 6 and 18 months. Setting: Level 3 neonatal intensive care unit. Patients and interventions: 25 newborns were recruited. The treated patients received a daily dose of intravenous melatonin, 5 mg per kg body weight, for 3 days. Results. After adjusting the data for severity, in the group treated with melatonin, there is a decrease in plasma levels of GM-CSF, IL-2 and IL-13 at T1 compared to placebo, as well as, at T2, in GM-CSF concentrations, as well as IL-7 and IL-13 at T3. Evolutionarily, we found a significant decrease in GM-CSF concentrations in the treatment group compared to placebo, with no differences for the rest of the biomarkers. It is noteworthy that the sustained decrease in GM-CSF and inflammatory cytokines IL-2, IL-7 and IL-13 correlated with better neurodevelopmental outcomes at 6 and 18 months. Conclusions. In neonates with hypoxic-ischemic encephalopathy, the addition of iv melatonin to hypothermia therapy affects the plasma concentration of biomarkers in the first week of life, with a high correlation with long-term neurological prognosis.