The importance of long chain polyunsaturated fatty acids for fetal immune system maturation and function
Long chain polyunsaturated fatty acids (LCPUFAs) are important structural components in the cell membrane and a deficiency in these fatty acids have been linked to clinical complications. In addition, omega 3 and omega 6 LCPUFAs are biologically active substrates for the synthesis of regulators of inflammatory processes. Preterm neonates and uninfected neonates born to HIV-infected women (DNI) are susceptible to immune complications. These babies may have deficiencies in LCPUFAs, but the impact of this loss on maturation of the immune system is unknown. Cord blood mononuclear cell (CBMC) membrane fatty acid content was examined by gas chromatography (GC), and immunological profiles as defined by flow cytometry were compared between healthy term, preterm and DNI neonates as an indicator of immune deficiencies. This was the first study to examine the lipid profile of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) fractions of CBMC membranes from preterm and DNI neonates. The LCPUFA composition of CBMCs was dominated by arachidonic acid (AA, 20:4co6) in the PE (34%) and PC fractions (15%) in term neonates (>37 weeks, n=9). Compared to term neonates, preterm (<37 weeks, n=10) and DNI (>37 weeks, n= 9) CBMC levels of both omega-3 and omega-6 LCPUFAs were significantly lower. In addition term neonates had significantly higher numbers of CD4 and CD8 leukocytes than preterm and DNI neonates, including naïve and memory lymphocytes. These deficiencies in vital LCPUFAs and immune subset numbers, may contribute to the immature status of the preterm and DNI immune system, and ultimately to compromised immune function. A preliminary study was conducted into the function of immune cells in vitro in media supplemented with omega 3 and omega 6 LCPUFAs. The results, while not conclusive, suggested that LCPUFAs were beneficial to lymphocytes in culture.
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