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Published on: November 15, 2024
Hyperglycemic brain injury in the rat
John I Malone1, Suzan K Hanna, Samuel Saporta
1Department of Pediatrics, College of Medicine, University of South Florida, Tampa, FL 33612, USA. jmalone@hsc.usf.edu
Insights
Continuous hyperglycemia, common in early childhood diabetes, may harm brain development more than intermittent hypoglycemia. This finding is crucial for managing diabetes in young children.
Area of Science:
- Neuroscience
- Endocrinology
- Pediatrics
Background:
- Type 1 diabetes onset in early childhood is linked to impaired neurocognitive function.
- Hypoglycemia, a complication of insulin therapy, has been implicated as the cause of cognitive deficits.
- Hyperglycemia, while manageable for older children, poses a risk to the developing brains of very young children.
Purpose of the Study:
- To investigate the differential effects of continuous hyperglycemia versus intermittent hypoglycemia on brain development in young rats.
- To determine if hyperglycemia, more prevalent in early childhood diabetes, impacts brain growth and maturation.
Main Methods:
- Young rats (4-8 weeks old) were subjected to either continuous hyperglycemia (diabetes) or intermittent hypoglycemia for 4 weeks.
- Brain tissue was analyzed biochemically for cell number, cell size, protein, fatty acids, and cholesterol content.
- Histological examination of brain tissue was performed to corroborate biochemical findings.
Main Results:
- Diabetic rats exhibited increased cortical cell number and reduced cell size compared to controls.
- Biochemical analysis revealed smaller cells with reduced myelin content in the cortex of diabetic animals.
- Histological findings confirmed the biochemical evidence of altered brain development in hyperglycemia.
Conclusions:
- Continuous hyperglycemia may exert a more detrimental effect on the developing brain than intermittent hypoglycemia.
- These findings have significant implications for the management of diabetes mellitus in young children.
- Further research is warranted to confirm and evaluate these observations for clinical relevance.
Abstract:
Children with diabetes onset before 5 years of age have reduced neurocognitive function. This problem has been attributed to hypoglycemia, a complication of insulin therapy. The eye, kidney, and nerve complications of diabetes (hyperglycemia) have been reduced by intensified insulin therapy which is associated with a 3-fold increase in severe hypoglycemia and therefore is not recommended for children less than 13 years of age. Since hyperglycemia is much more common than intermittent hypoglycemia during early childhood diabetes, it is important to determine if hyperglycemia affects brain growth and development. Rats were exposed to 4 weeks of either continuous hyperglycemia (diabetes) or intermittent (3 h, 3 times/week) hypoglycemia from 4 to 8 weeks of age. The brains of these animals were compared to those of similarly aged normal control animals. The cell number was increased, and the cell size reduced in the cortex of diabetic animals as assessed by DNA/wet weight of brain and protein/DNA content. Reduced amounts of protein, fatty acids, and cholesterol/microgram DNA also indicate smaller cells with reduced myelin content in the cortex of the diabetic animals. Histologic evaluation of these brains confirmed the biochemical findings. These observations require further confirmation and evaluation but indicate that continuous hyperglycemia may be more damaging than intermittent hypoglycemia to the developing brain. This is an important consideration for the management of diabetes mellitus in young children.
