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In children with advanced PNALD, low dose fish oil monotherapy (Omegaven) has been shown to biochemically reverse cholestasis4,5. Like SMOFlipid, Omegaven is not FDA approved and its use is restricted throughout the United States. Omegaven is dosed at 1 g/kg per day, lacks phytosterols, and contains high concentrations of the anti-inflammatory omega-3 fatty acids DHA and eicosapentaenoic acid, and vitamin E. Based on the assumption that reducing the liver’s exposure to phytosterols and omega-6 fatty acids treats PNALD, it has now become common clinical practice in many neonatal intensive care units to prescribe low dose soybean oil for PNALD prevention. While observational data suggests low dose soybean oil (1 g/kg per day or less) reduces the incidence of PNALD, randomized controlled trials have not demonstrated a change in cholestasis. Lipid sparing (fish or soy) is not without risks, particularly in high-risk populations such as preterm neonates. Inadequate lipid intake during a period of rapid growth and development could cause a fatty acid deficiency and impair growth and neurodevelopment. The central nervous system contains high concentrations of lipids, which are important for cell structure and function and gene transcription. One of the advantages of SMOFlipid is that it can be dosed at 3 g/kg per day, unlike Omegaven, and may be more likely to meet the lipid requirement of neonates.
In summary, the current FDA-approved soy-based lipid product was not designed to meet the nutritional needs of the preterm infant. An ideal lipid emulsion would provide adequate concentrations of polyunsaturated fatty acids, promote growth, be free of phytosterols, and minimize inflammation and other adverse sequelae. SMOFlipid may be more likely to meet the DHA and ARA requirement of the premature neonate. A mixed lipid emulsion dosed at 3 g/kg per day may improve growth and long-term neurodevelopment and reduce the incidence of parenteral nutrition associated liver disease along with other common neonatal diseases. In turn, this may reduce health care related costs. Appropriately powered, well-designed randomized controlled trials with long-term follow-up are needed to evaluate this new lipid emulsion.
References
1. J Pediatr Gastroenterol Nutr. 2010 Oct;51(4):514-21.
2. Nutr Clin Pract. 2012 Dec;27(6):817-24.
3. J Pediatr Gastroenterol Nutr. 2014 Apr;58(4):417-27.
4. JPEN J Parenter Enteral Nutr. 2016 Mar;40(3):374-82.
5. JPEN J Parenter Enteral Nutr. 2014 Aug;38(6):682-92.
Dr. Calkins is an assistant professor of pediatrics in the division of neonatology at the University of California, Los Angeles. She receives research funding from Fresenius Kabi, the German manufacturer of the products described in this article. The terms of this arrangement have been reviewed by UCLA in accordance with its conflict of interest policy. Because there is only one manufacturer for some of the products discussed in this article, for clarity we have chosen to use brand names rather than generic names. Email Dr. Calkins at pdnews@frontlinemedcom.com.