Vitamin D, Nerve Growth Factor and Nerve Conduction Studies in Adult Male Type 2 Diabetic Neuropathy Patients

Diabetic peripheral neuropathy (DPN) is one of the most frequent microvascular complications of both type1 (T1DM) and type2 diabetes mellitus (T2DM) . It involves damage to the peripheral nerves, leading to symptoms such as numbness, tingling, pain, and loss of sensation in the extremities, especially the feet and hands . It is the primary risk factor for lower limb ulcers, amputations and consequent disabling, that can significantly affect a person's quality of life.

Unfortunately, the exact pathogenesis of diabetic neuropathy is complex and multifactorial. However, several studies have shown that increased levels of blood glucose leads to several neuronal changes as accumulation of advanced glycation end products, mitochondrial impairment and DNA damage. Furthermore, Vitamin D deficiency is more common in people with T2DM, contributing its pathogenesis in many ways, including impairment of insulin secretion and increasing insulin resistance. Moreover, previous studies reported that low level of vitamin D is correlated with the presence and severity of sensory neuropathy . However, its pathogenesis has not yet been established.

Nerve growth factor (NGF) is a neurotrophic factor playing a major role in adult peripheral nerve system. It works by increasing nerve cell regeneration and decreasing degeneration, so NGF decreased levels induce peripheral nerve lesion in diabetic patients.

Several studies indicate that vitamin D may play a role in nutrition and protection of peripheral nerves as nerve cells and glial cells rich in vitamin D receptors, So vitamin D may have a potential effect in DPN by neuro-protection as it protect against apoptosis and degeneration, as well as it can trigger production of NGF helping preservation of neurons. Thus, we hypothesize that vitamin D, by regulating NGF expression, could help nerve regeneration and improve outcomes in patients with DPN.