Pain-related differential expression of NGF, GDNF, IL-6, and their receptors in human vasculitic neuropathies.

OBJECTIVE

Pain-related differential expressions of nerve growth factor (NGF), glial cell line-derived neurotrophic factor (GDNF) and interleukin-6 (IL-6), and their receptors were investigated in human vasculitic neuropathies.

MATERIALS AND

METHODS

The mRNA levels of pain-related neurotrophic factors, NGF, GDNF and IL-6, were examined in the sural nerves of 22 painful and non-painful patients with acute necrotizing vasculitic neuropathies, together with their concomitant soluble receptors (p75, GFR(alpha)-1 and IL-6R(alpha)).

RESULTS

The mRNAs for these factors and receptors in the lesioned nerves were up-regulated to a variable extent in both groups. NGF mRNA expression was more closely correlated with that of p75 in painful neuropathy with relatively preserved large fiber density, compared with non-painful neuropathy, though the NGF mRNA level in painful neuropathy was lower than that in non-painful neuropathy. GDNF was closely associated with GFR(alpha)-1 in mRNA levels regardless of the pain state, but IL-6 was not associated with IL-6R(alpha).

CONCLUSION

The differential expression of neurotrophic factors and their cognate soluble receptors in human vasculitic neuropathy suggests that NGF, which was effectively transferred to sensory axons with p75, may induce pain.