Enhancement of fat elimination during intravenous feeding

Tolerance of intravenously administered lipid in newborns

The tolerance for intravenously administered Intralipid in 262 premature and sick newborns was studied. The serum concentrations of triglycerides and of free fatty acids were determined during total parenteral nutrition including Intralipid in a maximum daily dose of 2 g/kg. A serum concentration of 1.5 mmol/l or higher was found in 270 out of 985 triglyceride determinations (27.4%). In the 262 infants serum triglyceride concentrations were found elevated once or more in 117 cases (44.7%). Serum free fatty acids concentrations were normal. A highly significant inverse correlation (p less than 0.001) between birth weight and triglyceride level was found. Elevated serum triglyceride concentrations were observed especially in preterm small-for-gestational-age infants.

Effect of parenteral hyperalimentation on serum lipoproteins and on lipoprotein lipase activity of adipose tissue and skeletal muscle

This study reports on the effects of parenteral nutrition with glucose along or in combination with Intralipid on heparin-releasable lipoprotein lipase (LPL) activity of adipose tissue and skeletal muscle and on serum lipoproteins. Thirteen patients with postoperative hypercatabolism and nine patients with caloric malnutrition were studied. The average adipose tissue LPL activity increased 5-fold during 4-day glucose infusion (P less than 0.001) and 7.4-fold during Intralipid plus glucose infusion (P less than 0.001). In contrast, no change occurred in the LPL activity of skeletal muscle. Glucose infusion caused a significant increase in VLDL and LDL triglyceride concentrations and the Intralipid plus glucose infusion was followed by a rise in LDL and HDL triglyceride concentrations. HDL cholesterol decreased by 26% (P less than 0.01) during glucose and by 19% (P less than 0.05) during Intralipid plus glucose. Apoprotein A I was very low already at the start of parenteral alimentation and it did not change during either nutrition. The HDL cholesterol and apoprotein A I and A II levels were each positively correlated with adipose tissue LPL activity before parenteral nutrition but not after it.

Lipid metabolism in the neonate. III. The ketogenic effect of Intralipid infusion in the neonate

The ketogenic potential of Intralipid was studied in two groups of infants: 12 were SGA and 15 AGA; all were clinically stable and less than 48 hours of age. During four-hour Intralipid tolerance tests, the SGA infants achieved significantly higher plasma TG and FFA levels. Both groups of infants significantly increased the concentration of ketone bodies; however, there was no difference in the levels achieved. In view of the slower clearance rate of TG and the higher levels of FFA in SGA infants, it is speculated that in addition to a possible defective lipoprotein lipase system and a decrease in number and size of the adipose cells, beta-oxidation of FFA to ketones may be occurring at a slower rate. The generation of high levels of ketones during Intralipid infusion period in both groups of infants indicates that SGA infants can handle ketone bodies as readily as AGA infants.

Utilization of fat emulsion during total parenteral nutrition in children

Tolerance for Intralipid fat emulsion during total parenteral nutrition (PN) was studied in 6 children. The Intralipid dose was monitored by the daily determination of plasma Intralipid levels. Fat removal was investigated at the start of and during the PN period by the intravenous fat tolerance test (IVFTT) and by determining the plasma postheparin lipoprotein lipase (LPL) activity. When the plasma Intralipid levels exceeded a value of 100 mg/100 ml, hyper pre-beta lipoproteinaemia, hypertriglyceridaemia, hypercholesterolaemia and hyperphospholipidaemia appeared. During PN most patients showed marked increases of postheparin LPL. Return to normal values occurred after discontinuation of PN. Maximal LPL activities were found to correlate significantly with total daily caloric intake (r=0.95, 0.05 less than p less than 0.01). The Intralipid elimination constant hardly changed during PN, with the exception of patient 6, who showed a marked increase (from 7 to 22%). Conclusions of this study are as follows: First a high caloric intake during PN leads to a marked increase of postheparin LPL activity. Second, by monitoring plasma Intralipid levels at 100 mg/100 ml approximately, it is possible to adjust the Intralipid dose in order to prevent hyperlipaemia and to take maximal benefit from rising fat tolerance. Thirdly the IVFTT appeared to be of little value to estimate the child's fat elimination capacity.