A new type of microvascular formation in the cerebral cortex – is there a link to cerebral hypoperfusion?

In several neuropathological autopsies, we observed a microvascular structure in the cerebral cortex that has not, to our knowledge, been previously described. We termed the structure a ‘raspberry’, referring to its appearance under a bright-field microscope. A raspberry consists of several microvascular lumen in immediate proximity to one another. The microvessels are likely capillaries or small arterioles. Raspberries have been identified in the cerebral cortex in various neuropathological diagnoses as well as in brains with no apparent neuropathology.

As microvascular structures, raspberries are likely formed through angiogenesis (the formation of new capillaries from already existing ones). The vasculature of the adult brain is stable under normal conditions, but angiogenesis can occur in response to various stimuli. Ischaemia is an important stimulus for angiogenesis, including in the brain. Given this, we hypothesize that raspberries are more frequent in brains that have been exposed to ischaemia, and thus could act as a marker for angiogenesis in the cerebral cortex.

This hypothesis can be addressed in several ways while expanding the knowledge of risk factors of and responses to cerebral ischaemia. By comparing the raspberry frequency between brains that have extensive or mild ischaemic injury, an association between raspberries and cerebral ischaemia has been indicated (see research output). Comparing potential risk factors for organ hypoperfusion between brains that have high or low raspberry frequency could provide further insight into the pathogenesis of raspberry formation. Searching raspberry-dense brains for signs of ongoing angiogenesis may indicate whether the proposed, proangiogenic stimulation is episodic or chronic. Identifying the components of raspberry microvessels could provide information on their age and thus if they are a result of recently induced, adult angiogenesis. Examining the ultrastructure of raspberries may indicate whether raspberry formation is an appropriate or pathological response to proangiogenic stimulation.

In summary, the project aims to provide insights into mechanisms of cerebral ischaemia and prevention thereof, and how the cerebral vasculature responds to hypoperfusion.