Lipids and Parenteral Nutrition

Disclosures Patent application submitted for Omegaven ® use

Learning Objectives Learn the difference between essential and non essential fatty acids Understand the theories of why a plant based omega 6 fat supplement may be less beneficial than an omega 3 diet

Questions What would happen if the digestive system does not exist or does not function and the only option is to feed intravenously? Patients given only intravenous nutrition are entirely dependent on the insight and skill of formulators. What would be in a well-designed intraveneous food to make it nutritionally replete?

Parenteral Nutrition (PN) Is given intravenously to patients with inadequate intestinal length or intestinal failure Contains lipids, amino acids, carbohydrates, vitamins, trace elements –Is life-saving but has known complications

Questions What are the essential fatty acids? What makes these fatty acids essential?

Polyunsaturated Fatty Acids Three main types of polyunsaturated FA’s (ω-3, ω-6, and ω-9)Three main types of polyunsaturated FA’s (ω-3, ω-6, and ω-9) Metabolized by the same set of enzymes in the preference: ω-3 > ω-6 > ω-9Metabolized by the same set of enzymes in the preference: ω-3 > ω-6 > ω-9 Serve various functions:Serve various functions: –membrane fluidity, bioactive metabolites, secondary messengers, platelet aggregation, vascular tone

Eicosapentaenoic acid EPA (20:5ω3) Docosahexaenoic acid DHA (22:6ω3) Arachidonic acid AA (20:4ω6) Eicosatrienoic acid (Mead Acid) MA (20:3ω9) Triene:Tetraene Ratio =Mead Acid/Arachidonic Acid. If ratio exceeds 0.2,  EFAD (essential fatty acid deficiency). Adapted from Le et. al. PLEFA Omega-3Omega-6Omega-9

Precursors of Eicosanoids Pro-inflammatory Anti-inflammatory Omega-3Omega-6 Adapted from Le et. al. PLEFA. 2009

Essential Fatty Acid Deficiency (EFAD) <1-2% of total calories are provided from α-Linolenic Acid and Linoleic Acid (EFAs)<1-2% of total calories are provided from α-Linolenic Acid and Linoleic Acid (EFAs) Animals: impaired growth, dermatitis, hepatic steatosis (fatty liver, kidney malfunction, pulmonary abnormalities, Animals: impaired growth, dermatitis, hepatic steatosis (fatty liver, kidney malfunction, pulmonary abnormalities, Decreased Arachidonic Acid levels and increased Mead Decreased Arachidonic Acid levels and increased Mead Acid level Mead Acid/Arachidonic Acid > 0.2 (Triene:Tetraene Ratio) In human: growth retardation, hair loss, infertility, In human: growth retardation, hair loss, infertility, Bleeding tendency, dry and scaly skin < 4-5% of calories in premature infants < 4-5% of calories in premature infants

A Liver lobule (cross section view) Bile duct Branch of portal vein Branch of hepatic artery Hepatic sinusoids Central vein

Liver removes hemoglobin breakdown products Bile ducts of liver lobules (prior slide) collect bilirubin in gall bladder. Billirubin excreted, unless…

Cholestasis Blockage of bilirubin excretion from the liver Clinically patients become yellow (jaundice)

Parenteral Nutrition Associated Liver Injury

Short Bowel Syndrome with Cholestasis Mortality is 37.5% due to liver failure and/or sepsis (Boston Children’s Hospital) Approx 25% mortality 25% transplant if received PN for 2 months (J. Peds 2012) Approach 90% mortality if cholestasis and remain on PN for > 1 year (Wales PW et al J. Ped. Surg. 2005) 1.4% of all deaths of children 4 years of age & under

Clinical Outcome Cholestasis is progressive while on PN Cirrhosis Liver failure Liver transplant or death

–Prematurity –Low birth weight –Duration of PN use –Absence of enteral feeds Risk Factors for PN-associated Liver Injury

Ideal Intravenous Lipid Emulsion Would reverse or prevent essential fatty acid deficiency Would not produce hepatic steatosis Would not be inflammatory Would prevent the elevation of liver enzymes

Comparison of Parenteral Fat Emulsions (10 grams fat/100 mL) OILIntralipidOmegaven Soybean10 Fish 10 % FATS Linoleic α-linolenic9 <0.2 E.P.A D.H.A Arachidonic acid Glycerol Phytosterols mg/L

Potential Benefits of Omega-3 Fatty Acids Anti-inflammatory properties - decreased production of pro-inflammatory cytokines Clearance Omega-3 fatty acids diminish de novo lipogenesis

Administration of two different IV Lipid Emulsions 19 Days HCD + Intralipid (IL) HCD + Omegaven (OM)

HCDILOM A B C Representative Images of Liver Tissue Stained with Oil Red O Kalish BT et al.

GPR120 (FFAR4) DHA and EPA are principal ligands Expressed in adipocytes, macrophages, (including kupffer), pancreatic beta cells Anti-inflammatory effects through NFkB Improved glycemic control through up-regulation of insulin

Hypothesis High levels of EPA and DHA in Omegaven contribute to its protection from PN-induced liver injury in part through GPR120 signaling

Experimental Strategy Oral PN WT PN + IV Saline WT PN + IV Fish Oil GPR120 KO PN + IV Saline GPR120 KO PN + IV Fish Oil Wild Type GPR120 KO

GPR120 is required for Omegaven-mediated prevention of PN-induced liver injury

Clinical Outcome Mortality/Transplant BCH is <5% No deaths or transplants due to liver disease at Boston Children’s in 4 years (80 new patients)

Conclusions Administration of nutrition intravenously vs orally can have profound metabolic effects and organ function Lipids are important mediators of inflammation and may have profound effects on specific organs Receptor binding is important in liver protection

Patient Presentation (Ellie) Ellie is 8 years old At birth lost over ¾ of her intestines Has been dependent on intravenous nutrition Developed jaundice on the soybean based lipid emulsion Transferred to Boston Children’s Hospital Liver disease resolved on the fish oil based lipid emulsion