Effect of insulin therapy on lipoproteins in non-insulin dependent diabetes mellitus (NIDDM).
Thirty patients with NIDDM and severe hyperglycemia (fasting plasma glucose greater than 200 mg/dl) were initiated on insulin therapy. Lipoprotein concentrations were measured by the Vertical Autoprofile procedure before insulin therapy and 1, 3, 6 and 26 weeks after insulin initiation. Patients were divided into 4 phenotypes based on their pretreatment lipoprotein profile: HyperVLDL (elevated VLDL), HyperLDL (elevated LDL), HyperVLDL-LDL (elevated VLDL and LDL), and non-hyperlipidemic. There were no differences in the initial fasting plasma glucose, Hgb Alc, or fasting free insulin concentrations between the groups. Both the HyperVLDL and HyperLDL groups had significantly lower HDL-C concentrations that the non-hyperlipidemic group and the HyperVLDL-LDL group had significantly higher IDL-C than any of the other groups. Insulin therapy resulted in similar decreases in fasting plasma glucose and increases in fasting free insulin concentrations in all 4 groups. HDL-C increased in all 4 groups. The most marked improvements in HDL-C were seen in the non-hyperlipidemic (+37%) and HyperLDL (+42%) groups while the HyperVLDL group had only an 18% increase. VLDL-C fell in all groups but in the HyperVLDL group it fell dramatically to almost normal levels within the first week, whereas it took 6 weeks for the HyperVLDL-LDL group to reach its VLDL-C nadir and this was still significantly higher than normal. LDL-C improved modestly in only the HyperLDL patients after 6 weeks of insulin therapy. There were no statistically significant changes in either the IDL-C or Lp(a)-C in any of the groups during insulin therapy. The changes in HDL-C and IDL-C were negatively correlated with the fasting plasma glucose and Hgb Alc but not with the free insulin concentration. We conclude that: 1) Insulin therapy can cause dramatic improvements in HDL-C and VLDL-C while it has only a mild suppressive effect on LDL-C and no statistically significant effect on IDL-C or Lp(a)-C. The degree of improvement in the lipid profiles varied considerably between the different lipid phenotypes. 2) The hyperlipidemic phenotypes seen in these patients appear to be determined primarily by factors other than the degree of hyperglycemia and hypoinsulinemia.
Hughes
T A
TA
Department of Medicine, University of Alabama at Birmingham, School of Medicine 35294.
Clements
R S
RS
Fairclough
P K
PK
Bell
D S
DS
Segrest
J P
JP
D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D005260:Female; D006801:Humans; D006943:Hyperglycemia / Q000188:drug therapy; D007328:Insulin / Q000494:pharmacology* / Q000627:therapeutic use; D008074:Lipoproteins / Q000097:blood* / Q000145:classification; D008297:Male; D008875:Middle Aged; D010641:Phenotype
D001786:Blood Glucose; D007328:Insulin; D008074:Lipoproteins