Open access review of diabetic neuropathy with a focus on the oft forgotten Schwann cell – Schwann cell interactions with axons and microvessels in diabetic neuropathy.
With Diabetes on the rise – close to half a billion people diagnosed world wide and a growth rate of 5% per year – and approximately 1 in 6 people with diabetes developing a painful neuropathy, there’s probably a good chance that primary contact clinicians will see patients presenting with undiagnosed diabetic neuropathies.
One for the Nerve Nerds
You should read the whole article (it’s quite accessible) but there are a few details that stand out as fascinating:
1. Glial cells (of which Schwann cells are a type) require relatively low energy under normal conditions, and research has demonstrated that Schwann cells in vitro, are damaged by hyperglycaemia. The paper suggests that Schwann cells may not be well adapted to metabolise excess glucose in the hyperglycaemic conditions present in diabetes.
2. Neurones on the other hand consume high amounts of energy and thrive in cultured environments that mimic physiological hyperglycaemia.
3. This might suggest that diabetic hyperglycaemia is more of a threat to Schwann cells than and is not a major factor in the axonopathy seen in the condition.
4. However, the loss of the trophic supporting actions of insulin is likely to have a direct and detrimental effect on axons, given that neurite outgrowth and axonal growth have both been shown to be enhanced by insulin, in vitro and in vivo respectively.
5. Finally, the thickening of the walls of endoneurial capillaries that is commonly seen in diabetic patients does not reduce the blood flow through the capillary bed, but instead creates shunts which increases the velocity of the blood flow thereby reducing efficient oxygen extraction causing hypoxia.
(I did say for the Nerve Nerds…)
A through review and an important read on this increasingly problematic painful condition.