Vitamin D deficiency is associated with an oxidized plasma cysteine redox potential in critically Ill children

Area of Science:

• Pediatric critical care medicine
• Nutritional biochemistry
• Oxidative stress research

Background:

• Critically ill children often experience high oxidative stress and vitamin D deficiency.
• Vitamin D plays a role in cellular functions, including immune response and redox balance.
• Understanding vitamin D's impact on oxidative stress markers is crucial for managing critically ill children.

Purpose of the Study:

• To investigate the relationship between vitamin D status and plasma redox markers (glutathione and cysteine) in critically ill children.
• To assess the association between vitamin D levels and markers of innate immunity.
• To explore the impact of vitamin D on oxidative stress in pediatric intensive care unit (PICU) patients.

Main Methods:

• Cross-sectional study of 50 PICU patients.
• Categorization of subjects based on plasma 25-hydroxyvitamin D [25(OH)D] concentrations.
• Measurement of plasma glutathione (GSH), glutathione disulfide (GSSG), cysteine (Cys), cystine (CySS), and LL-37 using HPLC and ELISA.
• Determination of redox potentials (E_hGSSG and E_hCySS).

Main Results:

• Vitamin D sufficiency (≥30ng/mL) was associated with a more reduced cysteine redox potential (E_hCySS), indicating lower oxidative stress (P=0.009).
• Plasma GSH, GSSG, and total GSH levels decreased with increasing vitamin D categories (P=0.01 for total GSH).
• Lower plasma glutamine levels were observed in vitamin D sufficient children (P=0.004).
• No significant difference in plasma LL-37 (innate immunity marker) was found across vitamin D status groups (P=0.08).

Conclusions:

• Vitamin D sufficiency in critically ill children correlates with a more reduced cysteine redox state, suggesting diminished oxidative stress.
• Despite reduced oxidative stress, vitamin D sufficiency was linked to lower levels of plasma GSH, GSSG, and glutamine.
• Further research is needed to elucidate the precise role of vitamin D in maintaining redox homeostasis during pediatric critical illness.