Navigation Links
Glucose Causes Death of Brain Cells in Rodents Following Hypoglycemic Coma

It was thought that hypoglycemic coma causes brain damage. On the contrary brain damage occurs only when glucose is given to treat the coma//, as discovered by researchers from San Francisco VA Medical Center, during a study on rodents.

The study results may have implications on the treatment of diabetics in hypoglycemic coma, though detailed research is necessary before it can be applied to humans.

Insulin is an essential hormone that moves glucose from the bloodstream to individual cells, where it is broken down and used for energy. Diabetics do not produce enough of their own insulin and must take it several times a day.

A severe insulin overdose can reduce levels of glucose in the blood to extremely low levels – a condition known as hypoglycemia – and cause hypoglycemic coma, resulting in destruction of neurons in the hippocampus and cerebral cortex, which are essential to memory and cognition.

'This study tells us for the first time that, in rats, the brain damage occurs not during the coma, but after it, when we give them glucose and their blood glucose levels return to normal,' says principal investigator Raymond A. Swanson, MD, chief of the neurology and rehabilitation service at SFVAMC.

Furthermore, says Swanson, he and his fellow researchers have identified the cause of the damage: the sudden return of glucose to the brain activates the enzyme NADPH oxidase, which in turn initiates a process of oxidative stress that is fatal to neurons.

Oxidative stress occurs when cells are poisoned by highly reactive forms of oxygen. Previously, it had been assumed that oxidative stress in neurons was initiated primarily by mitochondria, which process oxygen for energy within cells.

The paper appears in the April 2007 issue of the Journal of Clinical Investigation.

In their study, the researchers subjected rodents to a model of severe hypoglycemic coma. 'The rats could remain hypog lycemic without evidence of significant oxidative stress for at least 60 minutes,' says Swanson, who is also professor and vice-chair of neurology at the University of California, San Francisco. 'It was only when we gave them glucose to reverse the hypoglycemia that the oxidative stress occurred. This was a real surprise.'

The researchers then discovered that oxidative stress and neuron death were prevented when the rats were given an inhibitor of NADPH oxidase, indicating a key role for this enzyme.

'It is well-established that mitochondria can be a source of oxidative stress,' says Swanson. 'But in this setting, oxidative stress comes from an entirely different source.' He adds that the normal role of NADPH oxidase in the brain is 'completely unknown.'

The authors also found that the degree of oxidative stress was directly dependent upon the amount of glucose given. 'We think that this stems from a known link between glucose and NADPH oxidase,' Swanson says. 'Glucose is a precursor for NADPH, which in turn is used by NADPH oxidase in generating oxidative stress.'

Swanson explains that the results have implications for both basic and clinical science. For basic science, he says, 'this calls for a reconsideration of our concepts about the causes of oxidative stress in other settings – especially in ischemic stroke, where the blood supply to the brain is diminished and there’s a big burst of oxidative stress when the blood returns. That burst has always been blamed on oxygen, but it may be that glucose is the culprit. And it may depend on how much glucose is put in.'

In terms of clinical science, Swanson observes that 'as clinicians, our first reaction when we see a patient in hypoglycemic coma is to give lots of glucose, fast. But our rodent model makes it clear that overshooting glucose levels is very bad for rat brains. The way we treat patients for hypoglycemia may have to be reevaluated.'

Sw anson adds two strong cautions, however: 'First, the work was done in rodents, and it is not legitimate to immediately extrapolate these findings to humans. Second, there are many ways to go wrong in humans by not treating hypoglycemia aggressively enough. The results of this one paper do not mean that clinicians should take an overly cautious approach to hypoglycemic coma.'

In his own current research, Swanson is investigating the possible roles of glucose and NADPH oxidase as agents of oxidative stress in a rodent model of ischemic stroke. 'So far, the results are very promising,' he says.


Related medicine news :

1. Treatment For Sleep Apnea Found To Lower Blood Glucose Levels
2. Glucose may support in Cardiac Arrest
3. Critically Ill Patients More At Risk Of Infection If Glucose Is Present In Their Lung Secretions
4. Glucose Boosts Memory Retention
5. Glucose Enables Speedy Recovery From Malaria
6. Watch Out For the Erroneous Readings in the Glucose Meters
7. Abnormal Glucose Metabolism May Contribute to Chronic Nerve Disorder
8. Exercise in Itself Improves Blood Glucose Control in Type 2 Diabetes
9. Exercise in Itself Improves Blood Glucose Control in Type 2 Diabetes
10. Study Finds No Benefits On Self Monitoring Blood Glucose levels
11. Two Chemical Compounds Restore Healthy Glucose Levels In Obese Mice
Post Your Comments:

(Date:11/24/2015)... , ... November 24, 2015 , ... DMG Productions announced ... Begley Jr., airing first quarter 2016 via Discovery Channel. Dates and show times TBA. ... Province, and is in the business of producing and supplying medical marijuana pursuant to ...
(Date:11/24/2015)... (PRWEB) , ... November 24, 2015 , ... ... LENR HHT Bolier Reactor System. Brillouin is the developer of renewable energy technologies ... low energy nuclear reactions (“LENR”), announced today that its WET™ and HHT™ Boiler ...
(Date:11/24/2015)... ... 2015 , ... American Family Care (AFC), the nation’s leading provider of urgent ... located in Metro Atlanta’s North Point Mall. The clinic is designed to test the ... is scheduled to operate through Dec. 24. , Holiday Pop-Up Clinic , Official Opening ...
(Date:11/24/2015)... ... November 24, 2015 , ... ... been designated an Aetna Institute of Quality® Bariatric Surgery Facility for treating individuals ... and cost of health care services available to its members to help them ...
(Date:11/24/2015)... ... ... Bibliomotion is thrilled to announce the launch of UNCONVENTIONAL LEADERSHIP: ... Nancy M. Schlichting, Chief Executive Officer of Henry Ford Health System (November 24, ... patients and their families, shaped my desire to improve the system of care. I ...
Breaking Medicine News(10 mins):
(Date:11/25/2015)... , Nov. 25, 2015 Research and ... the "Membranes Market - Global Forecast to 2020" ... Asia-Pacific , accounting for 37.21% of the total ... Asia-Pacific region is projected to growth ... growth has been attributed primarily to the fast growing ...
(Date:11/25/2015)... 2015 --> ... Lizenz für das Patent über eine neue Hepatitis-B-Behandlung, welches ... innehaben, an Enyo Pharma vergeben haben. Im ... gerufenen und von Edelris gemeinsam mit seinen Partnern Inserm ... für HBV identifiziert, und es wurden neue Inhaltsstoffe entdeckt, ...
(Date:11/25/2015)... DUBLIN , November 25, 2015 ... has announced the addition of the  ... 2015-2019"  report to their offering.  ... announced the addition of the  "Global ...  report to their offering.  ...
Breaking Medicine Technology: