Paraoxonase and HDL Qualities in Glycaemia and Inflammation

Summary

The incidence of coronary heart disease (CHD) is significant in the super-obese and diabetics. Inflammation is believed to play an important part in the development of CHD, and the large collection of abdominal fat in the obese person is a vast source of inflammation. Diabetics have abnormal glucose and cholesterol metabolism which ultimately compromise their bodies' circulatory system and nerve function. Cholesterol plays a vital role in CHD. Low-density lipoprotein (LDL) particles carry cholesterol and deposit it in blood vessel walls which become damaged as a result. When LDL particles undergo changes chemically (called oxidation) or as a result of high circulating blood glucose (called glycation), they become more harmful to the body. High-density lipoprotein (HDL) particles have a protective function in CHD. Not only do they transport cholesterol away from the blood vessels to the liver to be broken down, they have properties against oxidation and inflammation. These properties are related to the activity of an enzyme on HDL called paraoxonase 1(PON1). Super-obese patients are increasingly treated by weight-reducing surgery (bariatric surgery). In this study we examine whether weight loss following bariatric surgery results in reduced inflammatory state, improved HDL function (higher PON1 activity), better control of blood glucose and less nerve damage. We will study PON1 activity, inflammation and glucose control in patients with type 1 diabetes (with and without kidney damage) and type 2 diabetes. We will also study the effects of rapidly rising blood glucose levels on PON1 and glycated LDL in patients undergoing oral glucose tolerance test.

Eligibility

Inclusion Criteria:

* Patients with Type 1 diabetes who are not receiving lipid-lowering drugs, omega fatty acid supplements or thiazolidinediones and without clinical and/or ECG evidence of CHD.

Type 2 diabetic patients who are not receiving omega fatty acid supplements or thiazolidinediones and without clinical and/or ECG evidence of CHD.

Patients with impaired fasting glucose undergoing oral glucose tolerance test. Patients scheduled for bariatric surgery. Healthy controls who have no major acute or chronic illness, are not receiving regular medication and not taking omega fatty acid supplements, do not have clinically overt ischaemic heart disease.

Subjects (male and female) aged between 20 and 75. Subjects who have capacity and understanding for informed consent process.

Exclusion Criteria:

* Type 1 diabetics using lipid lowering therapy, thiazolidinediones, omega fatty acid supplements. History and/or ECG evidence of ST segment changes indicative of CHD.

Type 2 diabetics receiving thiazolidinediones, omega fatty acid supplements. History and/or ECG evidence of ST segment changes indicative of CHD.

Healthy controls who have any history of CHD, vascular insufficiency, or diabetes. Use of any lipid-lowering drug or omega fatty acid supplements.

Conditions3

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