Pathophysiology of Diabetic Erectile Dysfunction
Pathophysiology of Diabetic Erectile Dysfunction
The ganglia where the cell bodies of the autonomic nerves are located are surrounded by small-diameter blood vessels (arterioles and venules) known as vasa nervorum, which supply the blood necessary for the function of the neurons. All nerve trunks, from large ones such as the sciatic nerve to small ones such as the cavernous nerve, have their own vasa nervorum. Earlier studies have shown that vasa nervorum of the peripheral nerve trunks can be divided into three groups: epineurial, perineurial and endoneurial. Epineurial and perineurial blood vessels form a complex network known as the epineurial plexus. The epineurial plexus has prominent arteriovenous shunts, supplies the endoneurial vascular compartment and is innervated by autonomic nerves such as sympathetic and peptidergic nerves. However, such detailed information is not available for the vasa nervorum of the autonomic ganglia, although ganglia have a much greater metabolic demand than peripheral nerve trunk. Whether the vasa nervorum of autonomic ganglia can be divided into sub-compartments like in the peripheral nerve trunk is not known. Moreover, details on the innervation of ganglion vasa nervorum are sparse. We have recently shown that the rat major pelvic ganglia are surrounded by numerous small diameter blood vessels (20-120 μm), which are innervated by noradrenergic and nitrergic nerve fibres. A drop in blood flow by as much as 50% is observed in the autonomic ganglia as early as 1 week after diabetes induction, although such an early decrease in blood flow is not associated with ED initially. Thus drawing parallels with vasa nervorum in nerve trunks, it is likely that such a reduction in perfusion would cause ganglionic neurons to be exposed to a hypoxic environment.
The Role of the Vasa Nervorum
The ganglia where the cell bodies of the autonomic nerves are located are surrounded by small-diameter blood vessels (arterioles and venules) known as vasa nervorum, which supply the blood necessary for the function of the neurons. All nerve trunks, from large ones such as the sciatic nerve to small ones such as the cavernous nerve, have their own vasa nervorum. Earlier studies have shown that vasa nervorum of the peripheral nerve trunks can be divided into three groups: epineurial, perineurial and endoneurial. Epineurial and perineurial blood vessels form a complex network known as the epineurial plexus. The epineurial plexus has prominent arteriovenous shunts, supplies the endoneurial vascular compartment and is innervated by autonomic nerves such as sympathetic and peptidergic nerves. However, such detailed information is not available for the vasa nervorum of the autonomic ganglia, although ganglia have a much greater metabolic demand than peripheral nerve trunk. Whether the vasa nervorum of autonomic ganglia can be divided into sub-compartments like in the peripheral nerve trunk is not known. Moreover, details on the innervation of ganglion vasa nervorum are sparse. We have recently shown that the rat major pelvic ganglia are surrounded by numerous small diameter blood vessels (20-120 μm), which are innervated by noradrenergic and nitrergic nerve fibres. A drop in blood flow by as much as 50% is observed in the autonomic ganglia as early as 1 week after diabetes induction, although such an early decrease in blood flow is not associated with ED initially. Thus drawing parallels with vasa nervorum in nerve trunks, it is likely that such a reduction in perfusion would cause ganglionic neurons to be exposed to a hypoxic environment.
