Search

Context: Patients with type 1 hyperlipoproteinemia (T1HLP), a rare genetic disorder, have extreme chylomicronemia and recurrent episodes of acute pancreatitis. Currently, the only therapeutic option is to consume an extremely low-fat diet because the triglyceride-lowering medications are not efficacious., Objective: To determine the efficacy of orlistat, a gastric and pancreatic lipase inhibitor, in reducing serum triglyceride levels in patients with T1HLP., Design and Setting: We conducted a randomized, open-label, clinical trial with a four-period, two-sequence ("orlistat" and "off orlistat" for 3 months), crossover study design., Patients: Two unrelated young Asian Indian males (11 and 9 years old) with T1HLP due to homozygous large GPIHBP1 deletions were enrolled at the UT Southwestern Medical Center. The patients were randomized to receive 3 months of orlistat or no therapy (off), then crossed over to the other arm, and this sequence was then repeated. Fasting serum triglyceride levels, fat-soluble vitamins, and gastrointestinal side effects were assessed., Results: Compared with the two off periods, orlistat therapy reduced serum triglycerides by 53.3% and 53.0% in patient 1 and 45.8% and 62.2% in patient 2. There was no deficiency of fat-soluble vitamin levels, and their growth continued. There were no serious adverse effects of orlistat; patient 1 had a mild increase in passage of gas and bloating, and patient 2 had constipation with mild stool leakage., Conclusion: Orlistat is safe and highly efficacious in lowering serum triglycerides in children with T1HLP and should be the first-line therapy in conjunction with an extremely low-fat diet.

Background: Lipoprotein lipase-deficient (LPLD) individuals display marked chylomicronemia and hypertriglyceridemia associated with increased pancreatitis risk. The aim of this study was to determine the effect of i.m. administration of an adeno-associated viral vector (AAV1) for expression of LPL(S447X) in muscle (alipogene tiparvovec, AAV1-LPL(S447X)) on postprandial chylomicron metabolism and on nonesterified fatty acid (NEFA) and glycerol metabolism in LPLD individuals., Methodology: In an open-label clinical trial (CT-AMT-011-02), LPLD subjects were administered alipogene tiparvovec at a dose of 1 × 10(12) genome copies per kilogram. Two weeks before and 14 wk after administration, chylomicron metabolism and plasma palmitate and glycerol appearance rates were determined after ingestion of a low-fat meal containing (3)H-palmitate, combined with (continuous) iv infusion of [U-(13)C]palmitate and [1,1,2,3,3-(2)H]glycerol., Principal Findings: After administration of alipogene tiparvovec, the triglyceride (TG) content of the chylomicron fraction and the chylomicron-TG/total plasma TG ratio were reduced throughout the postprandial period. The postprandial peak chylomicron (3)H level and chylomicron (3)H area under the curve were greatly reduced (by 79 and 93%, 6 and 24 h after the test meal, respectively). There were no significant changes in plasma NEFA and glycerol appearance rates. Plasma glucose, insulin, and C-peptide also did not change., Conclusions/significance: Intramuscular administration of alipogene tiparvovec resulted in a significant improvement of postprandial chylomicron metabolism in LPLD patients, without inducing large postprandial NEFA spillover.

Type I hyperlipoproteinemia (type I HLP) is a rare disorder of lipid metabolism characterized by fasting chylomicronemia and reduced postheparin plasma lipoprotein lipase (LPL) activity. Most cases of type I HLP are due to genetic defects in the LPL gene or in its activator, the apolipoprotein CII gene. Several cases of acquired type I HLP have also been described in the course of autoimmune diseases due to the presence of circulating inhibitors of LPL. Here we report a case of type I HLP due to a transient defect of LPL activity during puberty associated with chronic idiopathic urticaria (CIU). The absence of any circulating LPL inhibitor in plasma during the disease was demonstrated. The LPL genotype showed that the patient was heterozygous for the D9N variant. This mutation, previously described, can explain only minor defects in the LPL activity. The presence of HLP just after the onset of CIU, and the elevation of the LPL activity with remission of the HLP when the patient recovered from CIU, indicate that type I HLP was caused by CIU. In summary, we report a new etiology for type I HLP - a transient decrease in LPL activity associated with CIU and with absence of circulating inhibitors. This is the first description of this association, which suggests a new mechanism for type I HLP.

We describe a dramatic response to antioxidant therapy in three patients with familial lipoprotein lipase deficiency complicated by frequent severe episodes of pancreatitis who had failed to respond to other dietary and pharmacological measures. Antioxidant therapy may be an important advance in the management of this type of patient.