What is Metabolic Memory and How Does It Affect Diabetes?

”Metabolic memory” (less commonly known as ”hyperglycemic memory” or “legacy effect”) refers to the lingering effects of a long period of either poorly controlled or tightly controlled blood glucose levels, even once such control is either improved or lessened.

Well-Controlled Diabetes

In 2014, at an American Diabetes Association convention, results of an ongoing study called EDIC (Epidemiology of Diabetes Interventions and Complications) were released which showed that maintaining careful control of blood sugar levels over a number of years could lead to reduced cardiovascular disease in Type 1 diabetics. In fact, according to the study, for every 1% reduction in A1c levels, a corresponding 20% reduction in cardiovascular risk could be anticipated.

Researchers showed that patients with an A1c of 7% for six and a half years had a 57% reduced incidence of heart attacks and strokes, as compared to those with a sustained A1c of 9% for a similar amount of time. Importantly, this benefit continued even as those with the lower A1c lessened control in later years. The benefits appear to be the same for small blood vessel (microvascular) damage and large blood vessel (macrovascular) damage.

These studies were the follow-up to a large scale study of more than 1,400 type 1 diabetics known as the Diabetes Control and Complications Trial (DCCT). More than 90% of those who participated in the concluded first trial opted to join the second trial.

While these studies were done with type 1 diabetes patients, it is suggested that type 2 diabetes patients would benefit as much from similar periods of very tight control over their blood glucose levels.

The findings are specific to cardiovascular disease prevention. There is no indication that other possible outcomes of the disease are prevented.

Poorly-Controlled Diabetes

On the other hand, the effects of persistent hyperglycemia, even once corrected, can continue to contribute to other areas of vascular damage. This is also being referred to as metabolic memory or hyperglycemic memory.

A review of several studies, published as an abstract in the June 2012 issue of the journal Diabetes Research and Clinical Practice looked at research on the causes of Diabetic Retinopathy (DR.) DR is the result of damage to the fine blood vessels in the eye, and the article points to the continuing damage to these blood vessels from prolonged hyperglycemia, even after good control has been achieved.

Both of these findings are under serious study, in the hope that molecular therapeutics may be the key to prevention of these negative outcomes.

Sources: National Institutes of Health, Clinical Diabetes, Science Direct
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