Thursday, Mar. 6, 2008; 3:00 PM
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THURSDAY, March 6 (HealthDay News) — Chronically high blood glucose levels disable the molecular switch that normally turns off sugar production in the liver in response to increasing insulin levels, a California study finds.

This finding suggests that inhibiting the enzymatic pathway that disables the “sugar-off” switch (CRTC2) may help lower glucose levels in people with diabetes and reduce long-term complications associated with the disease, the researchers said.

The study, by researchers at the Salk Institute for Biological Studies, in La Jolla, Calif., is published in the March 7 issue of Science.

In healthy people, the CRTC2 switch turns on glucose production in the liver when blood glucose levels decline during the night. After a meal, insulin shuts down CRTC2, thus ensuring that blood sugar levels don’t rise too high.

But in many people with type 2 diabetes, CRTC2 no longer responds to increasing insulin levels. As a result, the liver keeps on pumping out glucose, even if blood glucose levels are already elevated.

In research with mice, the Salk team focused on the hexosamine biosynthetic pathway. Activation of this pathway promotes the addition of sugar molecules to proteins, a process called O-glycosylation.

“It had been known that increases in the concentration of circulating glucose activate the hexosamine biosynthetic pathway. But we had no idea that the resulting O-glycosylation would lock CRTC2 in the ‘on’ position,” study first author Renaud Dentin said in a prepared statement.

Dentin’s team decreased the activity of the hexosamine biosynthetic pathway in insulin-resistant diabetic mice and in mice fed a high-fat diet (both groups had high blood sugar levels) and found a marked improvement in glucose tolerance and insulin sensitivity.

TUESDAY, Feb. 26 (HealthDay News) — A national effort is needed to deal with the effects of high blood sugar in heart patients, says an American Heart Association scientific statement released Monday.

The statement highlights a number of unanswered questions about the condition, also known as hyperglycemia, in people hospitalized with acute coronary syndrome (ACS), which includes heart attack and a variety of other cardiovascular conditions.

“Although studies indicate that one-fourth to one-half of ACS patients have hyperglycemia when they arrive at hospital, elevated blood sugar is frequently ignored despite being strongly associated with increased mortality,” writing committee chair Dr. Prakash Deedwania, chief of cardiology at the VA Medical Center and the University of California, San Francisco, in Fresno, said in a prepared statement.

A number of studies have shown that hospitalized ACS patients with high blood sugar have increased rates of in-hospital complications and death. But much more needs to be learned about the link between hyperglycemia and poor outcomes in these patients. For example, it’s unclear whether elevated blood sugar levels in ACS patients are a marker for heart muscle damage or actually cause the damage, Deedwania noted.

Since evidence about how best to approach glucose management in ACS patients is still being gathered, the AHA statement provides “a general reference” for medical teams treating these patients.

The statement recommends that all ACS patients with elevated blood sugar be screened for diabetes or prediabetes as part of their in-hospital evaluation. Blood sugar should be kept in the range of 90 to 140 mg/dL for ACS patients who have significant hyperglycemia on admission and are placed in the intensive care unit. Blood sugar levels should be kept below 189 mg/dL for ACS patients who aren’t in the ICU.

The statement is published in the Feb. 26 issue of Circulation.

“This is a call to action for organizations such as the National Institutes of Health [NIH] to design appropriate large, randomized clinical trials where several of these critical and clinically important questions can be answered. Only then will we be able to find and implement treatments that may reduce deaths,” Deedwania said.

Hyperglycemia can be a serious problem if you don’t treat it. Hyperglycemia is a major cause of many of the complications that happen to people who have diabetes. For this reason, it’s important to know what hyperglycemia is, what its symptoms are, and how to treat it.

Hyperglycemia is the technical term for high blood glucose (sugar). High blood glucose happens when the body has too little, or not enough, insulin or when the body can’t use insulin properly.

A number of things can cause hyperglycemia. For example, if you have type 1 diabetes, you may not have given yourself enough insulin. If you have type 2 diabetes, your body may have enough insulin, but it is not as effective as it should be.

The problem could be that you ate more than planned or exercised less than planned. The stress of an illness, such as a cold or flu, could also be the cause. Other stresses, such as family conflicts or school or dating problems, could also cause hyperglycemia.

What are the symptoms of hyperglycemia?

The signs and symptoms include: high blood glucose, high levels of sugar in the urine, frequent urination, and increased thirst.

Part of managing your diabetes is checking your blood glucose often. Ask your doctor how often you should check and what your blood glucose levels should be. Checking your blood and then treating high blood glucose early will help you avoid the other symptoms of hyperglycemia.

It’s important to treat hyperglycemia as soon as you detect it. If you fail to treat hyperglycemia, a condition called ketoacidosis (diabetic coma) could occur. Ketoacidosis develops when your body doesn’t have enough insulin. Without insulin, your body can’t use glucose for fuel. So, your body breaks down fats to use for energy.

When your body breaks down fats, waste products called ketones are produced. Your body cannot tolerate large amounts of ketones and will try to get rid of them through the urine. Unfortunately, the body cannot release all the ketones and they build up in your blood. This can lead to ketoacidosis.

Ketoacidosis is life-threatening and needs immediate treatment. Symptoms include:

• shortness of breath
• breath that smells fruity
• nausea and vomiting
• a very dry mouth

Talk to your doctor about how to handle this condition

How do you treat hyperglycemia?

Often, you can lower your blood glucose level by exercising. However, if your blood glucose is above 240 mg/dl, check your urine for ketones. If you have ketones, do NOT exercise.

Exercising when ketones are present may make your blood glucose level go even higher. You’ll need to work with your doctor to find the safest way for you to lower your blood glucose level.

Cutting down on the amount of food you eat might also help. Work with your dietitian to make changes in your meal plan. If exercise and changes in your diet don’t work, your doctor may change the amount of your medication or insulin or possibly the timing of when you take it.

How do you prevent hyperglycemia?

Your best bet is to practice good diabetes management. The trick is learning to detect and treat hyperglycemia early — before it can get worse.