Diabetes and cardiovascular disease

Postprandial triglycerides - a major diabetic CVD risk factor:
Many type 2 diabetics have extremely high lipid (triglyceride) levels, particularly after eating fatty meals (postprandial).  A number of recent studies have shown that diabetic postprandial lipemia is a major cardiovascular risk factor. 

Postprandial triglyceride levels in type 2 diabetics

Triglycerides remain elevated in type 2 diabetics long after eating.

Flow chart showing the progression of atherosclerosis in type 2 diabetes.

Figure 1:  Tanaka, J. Atheroscler Thromb, 2004; 11:322-329E
Figure 2:  Tushuizen, Postgrad Med J 2005;81:16

Postprandial triglycerides are packaged into large lipoproteins called chylomicrons.  These scatter light, and give lipemic plasma its characteristic milky color.  As it turns out, this turbidity correlates well with both triglyceride levels and levels of postprandial lipemia.  In the photo below, the chylomicrons are the large particles on the upper left. Note their large size relative to the VLDL, LDL, and HDL particles.

In type 2 diabetes, the chylomicrons circulate in the bloodstream in excessive amounts after fatty meals. The chylomicrons are broken down into smaller, more-dangerous lipoproteins such as small LDL, which adhere to the linings of arteries, causing atherosclerosis. The resulting fatty build-up causes damage to the lining of the artery, leading to atherosclerosis, coronary artery disease, and other types of cardiovascular disease

Postprandial triglycerides circulate as  large chylomicron particles, which degrade to more dangerous small-LDL reminants. The small-LDL reminants adhere to artery linings, stimulating an inflamitory reaction that leads to atherosclerosis.

The problem is that postprandial lipemia is invisible to both diabetics and their physicians. Physicians don't detect postprandial lipemia because the standard lipid panel only tests fasting triglycerides. Patients don't detect postprandial lipemia because it generates no symptoms, and is presently undetected by blood glucose tests, which the diabetic typically performs several times a day. Since the problem is largely invisible, postprandial lipemia is almost always untreated, contributing to the gradual onset of cardiovascular disease.



Therapeutic options exist that can reduce lipemia:
A large number of different therapeutic, dietary, and exercise regimens are effective at decreasing the extent of postprandial lipemia and the risk of cardiovascular disease. Therapeutic regimens include statins, fibric acid derivatives, bile acid sequestrants, nicotinic acid, and hormone replacement therapy. Dietary regimens include use of omega-3 fatty acids (common in flax and fish oil), avoidance of high fat diets, and proper choice of dietary fats. Exercise and weight loss also reduce postprandial lipemia.



To correct it, you must detect it:
Ideally, what is needed is a next-generation blood glucose monitor that is just as inexpensive and easy to use as current blood glucose monitors, but which gives a lipemia measurement as well as the blood glucose measurement. Current blood glucose monitors already have timekeeping capability, memory, and onboard data management, which give the patient a historical perspective of how their glucose measurement fluctuates throughout a day. If these meters did the same thing for lipemia as well, then postprandial lipemia issues would be quickly revealed, and the patients could then take steps to address this issue.


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