In:
Journal of Cerebral Blood Flow & Metabolism, SAGE Publications, Vol. 27, No. 3 ( 2007-03), p. 469-476
Abstract:
To examine the impact of excessive erythrocytosis on local cerebral blood flow (CBF) and cerebral glucose metabolic rate (CMR glc ), we made use of our constitutively erythropoietin (Epo)-overexpressing transgenic mouse line (tg-6) that reach a mean hematocrit of 0.87. Compared with wild-type (wt) control siblings, CBF decreased by 44% in tg-6 mice, while upon hemodilution (tg-6-HD) to a physiologic hematocrit (e.g., 0.44) tg-6-HD mice returned the CBF to wt levels. Cerebral blood flow was determined in another transgenic mouse line that overexpresses human Epo in the brain only (tg-21): CBF increased by 17% compared with wt controls. However, oxygen delivery was similar in all four mouse groups tested (wt, tg-6, tg-6-HD and tg-21). Mean CMR glc was higher in tg-6 (+72%), tg-6-HD mice (+43%) and tg-21 (+22%) than in wt mice. Local CMR glc was higher in all 40 brain regions in tg-6 but only in 15 and 8 regions in tg-6-HD and tg-21 mice. These results show that prolonged increases in hematocrit did not alter cerebral oxygen delivery at a decreased CBF and increased CMR glc . Hemodilution suggests that high blood viscosity is a cause of the decrease in CBF and partly of the increase in CMR glc . Cerebral glucose metabolic rate may also be increased by a direct effect of Epo in the brain (tg-21 mice).
Type of Medium:
Online Resource
ISSN:
0271-678X
,
1559-7016
DOI:
10.1038/sj.jcbfm.9600360
Language:
English
Publisher:
SAGE Publications
Publication Date:
2007
detail.hit.zdb_id:
2039456-1
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