Suppression of serum lipid transfer proteins involved in high-density lipoprotein cholesterol metabolism by intensive insulin therapy in the first year of type 1 diabetes: Prospective InLipoDiab1 Study

Abstract Background and aims Cholesteryl ester transfer protein (CETP) and phospholipid transfer protein (PLTP) are crucial proteins in reverse cholesterol transport. There are insufficient data on regulating these proteins by insulin therapy in type 1 diabetes (T1DM). We aimed to assess prospectively the impact of insulin therapy initiation on transfer proteins serum levels in adults with newly diagnosed T1DM. Methods and Results 57 adults with newly diagnosed T1DM were enrolled in the InLipoDiab1 Study. All participants were treated with subcutaneous insulin in the model of intensive insulin therapy since the diagnosis of diabetes. Serum PLTP and CETP concentrations were measured at diagnosis, after three weeks, six months, and after one year of insulin treatment, using the immunoenzymatic method ELISA. A significant decrease in PLTP and CETP concentrations were demonstrated during 12 months of insulin therapy in newly diagnosed T1DM. The dynamics of changes in the level of these proteins varied depending on the occurrence of remission after a year of the disease. In the group without remission, a significant decrease in PLTP and CETP levels appeared after six months of follow-up. The remission group was characterized by a decrease in proteins concentration only after one year of treatment. In the non-remission group, significant negative correlations were found between the daily dose of insulin and levels of PLTP and CETP. Conclusion Exogenous insulin is an inhibitor of lipid transfer proteins involved in high-density lipoprotein cholesterol metabolism in the first year of treatment.