Pancreatic bile-salt-dependent lipase activity in serum of diabetic patients: is there a relationship with glycation?

1. Pancreatic bile-salt-dependent lipase has been detected in human plasma where it has the capability to modify normal low- and high-density lipoprotein composition and structure and to reduce the atherogenicity of oxidized low-density lipoprotein (Shamir R, Johnson WJ, Morlock-Fitzpatrick K, Zolfaghari R, Li L, Mas E, Lombardo D, Morel DW, Fisher EA. Pancreatic carboxyl ester lipase: a circulating enzyme that modifies normal and oxidized lipoproteins in vitro. J Clin Invest 1996; 97: 1696-704). 2. In the present study, we investigated the effect of glycation and particularly that of human serum albumin on the activity of bile-salt-dependent lipase. In vitro, bile-salt-dependent lipase activity decreased in the presence of human serum albumin; however, this was less pronounced in the presence of glycated human serum albumin. In vivo, bile-salt-dependent lipase specific activity was about 2-fold higher in the sera of diabetic patients than in the sera of normal subjects. 3. A significant increase in the specific activity of bile-salt-dependent lipase related to the serum level of glycation was observed. The increase in bile-salt-dependent lipase specific activity was not related to the glucose concentration in serum suggesting that glycation of bile-salt-dependent lipase could not be involved in the observed effects. Although the stability of serum bile-salt-dependent lipase was important enough to allow a systemic action of the enzyme on lipoproteins, it could not explain the higher activity of the enzyme in diabetic serum. 4. We concluded that bile-salt-dependent lipase could be helpful against the premature development of atherosclerosis in diabetes.