The roles of cerebral blood flow, capillary transit time heterogeneity, and oxygen tension in brain oxygenation and metabolism.
The roles of cerebral blood flow, capillary transit time heterogeneity, and oxygen tension in brain oxygenation and metabolism.
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DOI：
10.1038/jcbfm.2011.153
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发表时间：
2012-02
期刊：
影响因子：
--
通讯作者：
Østergaard L
中科院分区：
文献类型：
--
作者：
Jespersen SN;Østergaard L
正常的大脑功能关键依赖于血流对氧气供应的时刻调节，以满足不断变化的新陈代谢需求。神经血管偶联是一系列聚集在小动脉上调节局部脑血流量(CBF)的机制，代表了我们目前理解这一调节的框架。我们模拟了对于给定的组织氧分压，CBF和毛细血管通过时间异质性(CTTH)对生物物理支持的最大氧提取分数(OEFmax)和氧的代谢率的联合影响。大鼠大脑中的红细胞速度记录通过CBF和CTTH在一系列生理条件下支持密切的血流动力学-代谢耦合。CTTH的减少通过抵消脑血流量增加时OEFmax的固有减少来改善组织氧合，并似乎在皮质激活或低氧血症引起的充血发作期间确保了足够的氧合。在低灌流和CBF阻断状态下，低氧分压和CTTH均可确保组织氧合。我们的模型预测，紊乱的毛细血管流动可能导致恶性CTTH，在这种情况下，CBF较高的状态显示出较低的氧气利用率。我们认为，毛细血管形态改变的情况，如淀粉样蛋白、糖尿病或高血压微血管病变，以及缺血-再灌注，可能会干扰CTTH，从而影响血流-代谢耦合和脑氧代谢。
Normal brain function depends critically on moment-to-moment regulation of oxygen supply by the bloodstream to meet changing metabolic needs. Neurovascular coupling, a range of mechanisms that converge on arterioles to adjust local cerebral blood flow (CBF), represents our current framework for understanding this regulation. We modeled the combined effects of CBF and capillary transit time heterogeneity (CTTH) on the maximum oxygen extraction fraction (OEFmax) and metabolic rate of oxygen that can biophysically be supported, for a given tissue oxygen tension. Red blood cell velocity recordings in rat brain support close hemodynamic–metabolic coupling by means of CBF and CTTH across a range of physiological conditions. The CTTH reduction improves tissue oxygenation by counteracting inherent reductions in OEFmax as CBF increases, and seemingly secures sufficient oxygenation during episodes of hyperemia resulting from cortical activation or hypoxemia. In hypoperfusion and states of blocked CBF, both lower oxygen tension and CTTH may secure tissue oxygenation. Our model predicts that disturbed capillary flows may cause a condition of malignant CTTH, in which states of higher CBF display lower oxygen availability. We propose that conditions with altered capillary morphology, such as amyloid, diabetic or hypertensive microangiopathy, and ischemia–reperfusion, may disturb CTTH and thereby flow-metabolism coupling and cerebral oxygen metabolism.
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DOI：
10.3389/fnene.2010.00008
发表时间：
2010
期刊：
Frontiers in neuroenergetics
影响因子：
--
作者：
Buxton RB
通讯作者：
Buxton RB
DOI：
10.1073/pnas.83.4.1140
发表时间：
1986-02-01
影响因子：
11.1
作者：
FOX, PT;RAICHLE, ME
通讯作者：
RAICHLE, ME
DOI：
10.1073/pnas.95.26.15741
发表时间：
1998-12-22
影响因子：
11.1
作者：
Kleinfeld, D;Mitra, PP;Denk, W
通讯作者：
Denk, W
DOI：
10.1097/00004647-199701000-00009
发表时间：
1997-01-01
影响因子：
6.3
作者：
Buxton, RB;Frank, LR
通讯作者：
Frank, LR
影响因子：
3.8
作者：
Dash, Ranjan K.;Bassingthwaighte, James B.
通讯作者：
Bassingthwaighte, James B.