Postprandial chylomicrons and adipose tissue lipoprotein lipase are altered in type 2 diabetes independently of obesity and whole-body insulin resistance.
OBJECTIVE
Postprandial lipoprotein abnormalities in type 2 diabetes are associated with insulin resistance. The role of other diabetes-related factors is still not clear. The aim of this study is to differentiate the effects of whole-body insulin resistance, obesity, and type 2 diabetes on postprandial dyslipidaemia and lipoprotein lipase (LPL) in adipose tissue.


RESULTS
Ten subjects with obesity and diabetes (OD), 11 with obesity alone (O), and 11 normal-weight controls (C) - males, aged 26-59 years, with fasting normo-triglyceridaemia underwent measurements of cholesterol, triglycerides, apo B-48 and apo B-100 concentrations in plasma lipoproteins separated by density gradient ultracentrifugation before and after a fat-rich meal. Fasting and postprandial (6h) LPL activity was determined in abdominal subcutaneous adipose tissue biopsy samples. Insulin sensitivity was measured by hyperinsulinaemic euglycaemic clamp. OD and O subjects had similar degrees of adiposity (BMI, waist circumference, fat mass) and insulin resistance (insulin stimulated glucose disposal and M/I). They also showed a similarly higher postprandial increase in large VLDL lipids (triglyceride incremental AUC 188+/-28 and 135+/-22 mg/dl.6h) than C (87+/-13 mg/dl.6h, M+/-SEM, p<0.05). OD had an increased chylomicron response compared to O (triglyceride incremental AUC 132+/-23 vs. 75+/-14 mg/dl.6h, p<0.05). OD had significantly lower fasting and postprandial adipose tissue heparin-releasable LPL activity than O and C.


CONCLUSIONS
In insulin-resistant conditions of obesity, with and without diabetes, large VLDL are increased after a fat-rich meal. In addition, diabetic patients compared to obese subjects have an increased postprandial chylomicron response and a reduced adipose tissue LPL activity.
Annuzzi
Giovanni
G
Department of Clinical and Experimental Medicine, Federico II University, Via Pansini 5, 80131 Naples, Italy. annuzzi@unina.it
Giacco
Rosalba
R
Patti
Lidia
L
Di Marino
Lucrezia
L
De Natale
Claudia
C
Costabile
Giuseppina
G
Marra
Maurizio
M
Santangelo
Carmela
C
Masella
Roberta
R
Rivellese
Angela A
AA
D000273:Adipose Tissue / Q000201:enzymology*; D000328:Adult; D015992:Body Mass Index; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D002914:Chylomicrons / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000201:enzymology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000201:enzymology / Q000378:metabolism*; D019518:Postprandial Period; D012016:Reference Values; D014280:Triglycerides / Q000097:blood; D055815:Young Adult
D008076:Cholesterol, HDL; D002914:Chylomicrons; D014280:Triglycerides; D002784:Cholesterol; D008071:Lipoprotein Lipase