Related Experiment Videos
Cognitive deficits induced by global cerebral ischaemia: relationship to brain damage and reversal by transplants
Insights
Global ischemia can cause memory loss by damaging the hippocampus (CA1 region). This review explores cognitive deficits and potential cell grafting strategies to restore function after brain ischemia.
Area of Science:
- Neuroscience
- Neuropathology
- Cerebrovascular Medicine
Background:
- The hippocampus, particularly the CA1 and hilar fields, is vulnerable to oxygen deprivation following interrupted cerebral blood flow.
- Ischemic damage to the hippocampus is a primary cause of anterograde memory loss in survivors of cardiac events.
- Animal models of global ischemia are crucial for understanding and mitigating the effects of transient cerebral blood flow interruption.
Purpose of the Study:
- To review the cognitive deficits resulting from global ischemia and their correlation with hippocampal CA1 cell loss.
- To examine the potential for graft-induced recovery of cognitive function in animal models of global ischemia.
- To explore the therapeutic implications of fetal cell grafts and growth factors for protecting the CA1 sector and reducing cognitive deficits.
Main Methods:
- Review of existing literature on cognitive deficits following global ischemia in animal models.
- Analysis of lesion-based accounts of hippocampal function and correlation with CA1 cell loss.
- Examination of studies investigating the efficacy of fetal cell transplantation and growth factors in mitigating ischemic brain damage.
Main Results:
- Global ischemia induces specific cognitive deficits consistent with hippocampal damage, particularly affecting CA1 regions.
- Evidence suggests that grafted fetal cells can integrate into host hippocampal circuitry.
- Growth factors show promise in protecting neurons from ischemic injury.
Conclusions:
- Cellular grafts, particularly from discrete hippocampal fields, may restore function in the CA1 region damaged by ischemia.
- Trophic support from grafts or growth factors could protect vulnerable hippocampal sectors and alleviate cognitive deficits.
- Further research into cell-based therapies holds promise for treating memory loss associated with ischemic brain injury.
Abstract:
The CA1 and hilar fields of the hippocampus are highly vulnerable to lack of oxygen after interruption of blood flow to the brain. Severe anterograde memory loss, seen in a significant proportion of heart attack survivors, has been attributed to selective bilateral ischaemic damage to the hippocampus. Animal models of global ischaemia, induced by extracranial occlusion of the major ascending arteries, enable assessment of the neuropathological and functional consequences of transient interruption of cerebral blood flow, and can inform strategies to reduce or alleviate ischaemic brain damage. This review focuses firstly on the nature of cognitive deficits induced by global ischaemia, how far they are consistent with lesion-based accounts of hippocampal function, and the extent to which these deficits can be correlated with CA1 cell loss. The second focus of the review is to examine the limited evidence for graft-induced recovery of cognitive function in animals subjected to global ischaemia. Recent findings that grafted foetal cells from discrete hippocampal fields follow appropriate laminar routes to form functional connections with host neurons, and that growth factors protect cells from ischaemic damage, have suggested that CA1 or trophic grafts placed in the region of ischaemic CA1 cell loss might restore or protect this vulnerable sector, and reduce cognitive deficits.