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CSF concentration and CSF/blood ratio of fuel related components in children after prolonged fasting
K J Lamers1, W H Doesburg, F J Gabreëls
1Laboratory of Clinical Chemistry, Radboud Hospital, University of Nijmegen, The Netherlands.
Insights
This study examined fuel substrates in children's blood and cerebrospinal fluid (CSF) after fasting. Ketone bodies compensate for lower glucose in younger children's CSF, maintaining energy homeostasis.
Area of Science:
- Biochemistry
- Pediatrics
- Neuroscience
Background:
- Fuel substrate concentrations in blood and cerebrospinal fluid (CSF) are critical for understanding energy metabolism, especially during fasting.
- Limited data exists on the relationship between blood and CSF fuel substrates in children across different age groups and fasting durations.
Purpose of the Study:
- To investigate blood and CSF concentrations and CSF/blood ratios of fuel-related substrates in children after prolonged fasting.
- To analyze the influence of age and sex on these substrate levels and ratios.
- To assess the contribution of different substrates to CSF caloric homeostasis.
Main Methods:
- Biochemical analysis of blood and CSF samples from control children undergoing standardized fasting tests.
- Inclusion of two age groups: 3-5 years (24h fast) and 6-15 years (40h fast).
- Statistical analysis to determine correlations between substrates, age, and sex.
Main Results:
- Good correlation observed between blood and CSF concentrations for glucose, acetoacetate, and beta-hydroxybutyrate.
- Glucose levels in blood and CSF positively correlated with age; ketone levels negatively correlated with age in older children.
- CSF pyruvate showed age-related changes, while lactate and alanine did not. Acetoacetate CSF/blood ratio was age and sex-dependent.
Conclusions:
- Ketone bodies play a crucial role in maintaining CSF caloric homeostasis, compensating for reduced glucose in younger children during prolonged fasting.
- Age significantly influences glucose and ketone levels in both blood and CSF, highlighting developmental metabolic adaptations.
- Understanding these substrate dynamics is vital for pediatric metabolic research and clinical management.
Abstract:
In order to obtain information about blood and cerebrospinal fluid (CSF) concentrations, and CSF/blood ratio data of fuel related substrates at the end of a prolonged fast in children, we have selected biochemical data from fasting test procedures in 11 control children aged 3-5 yr, fasted 24 h, and 58 control children aged 6-15 yr, fasted 40 h. There was a good correlation between blood and CSF concentrations for glucose, acetoacetate and beta-hydroxybutyrate. The relation with age and sex has been analyzed only in the older children. CSF and blood values for glucose are positively related with age, and both ketones are negatively related with age. Lactate, pyruvate and alanine concentrations in blood and CSF are not related with age, except for CSF pyruvate. With respect to the CSF/blood ratio for the above mentioned components, only the value for acetoacetate is sex and age related. The calculated median caloric values for the sum of glucose, lactate, pyruvate and ketones in CSF are independent of age at the end of a 40-h fast. The diminished glucose contribution on the CSF caloric homeostasis in younger children is fully compensated by the ketone bodies.