Reduced Plasma Lipoprotein Lipase Activity in Patients with Malignancy-Associated Weight Loss

Summary

Post-heparin plasma lipoprotein lipase activity was measured in 28 cancer patients with varying degrees of weight loss, and in 16 normal volunteers. Total lipoprotein lipase activity was decreased by 35.4% (P < 0.001) in the cancer group. The component lipase activities, hepatic (H_LPL), and peripheral (P_LPL) were decreased by 40% (P < 0.001) and 38% (P < 0.005) respectively. In addition, the level of total peripheral lipoprotein lipase correlated well with the percent body weight lost by these patients (r = 0.6, P < 0.01). Regardless of extent of disease, patients with lung cancer showed the lowest enzyme activity (mean 191 mU/ml ± 30 SEM, P < 0.001) and the greatest percent of weight loss (mean 16%), while patients with breast cancer had nearly normal lipase activity (mean 315 mU/ml ± 50 SEM, normal 340 mU/ml ± 22 SEM, P < 0.10) and minimal weight loss (mean 8.4%).

Fasting serum triglycerides were significantly elevated in the patient group (mean 120 mg/dl ± 9.7 SEM) as compared to normal (mean 71 mg/dl ± 7 SEM, P < 0.001). The mean fasting insulin level was elevated in the patient group (13 mU/ml ± 3.0 SEM), although in the majority of the patients it was found within the normal range (4-24 mU/ml).

We conclude that the significant decrease in the total LPL activity may be responsible in part for the characteristic hypertriglyceridemia present in cancer patients.

Key-Words

Lipoprotein Lipase - Cachexia - Cancer