Extracellular Matrix Remodeling In Peripheral Neuropathies

Abstract

The role of extracellular matrix (ECM) in the development and maintenance of the normal nervous tissue structure has been demonstrated. However, little is known about ECM modifications taking place in peripheral nerve pathology. This gap has prompted us to study the expression of several components of the peripheral nerve ECM in the major categories of human peripheral neuropathies. Normal and pathological sural nerve biopsies, including cases of CMT1, HNPP, CIDP and axonal neuropathies were studied by immunohistochemistry for the expression of collagen (COL) types I, III, IV, V, VI, laminin (LN), tenascin (TN), fibronectin (FN) and vitronectin (VN). The immunoreactivity of ECM proteins in pathologic nerves showed different patterns in relation to their distribution in normal nerves. Indeed, COL I and III, which are the main stromal components of the epineurium and endoneurium, respectively, showed increased expression in these compartments, generally in chronic neuropathies. COL IV, V, VI and LN localized mainly to basement membranes (BM) of Schwann cells, perineurial cells and blood vessels, showing increased deposition in the presence of BM redundancy. FN localized diffusely to the endoneurium and perineurium in control nerves and its expression increased in CIDP nerves. VN immunoreactivity was limited to several spots along the perineurium and epineurial vessels in normal nerve. However, in CIDP and in some cases of axonal neuropathy the VN signal was increased in the perineurium and appeared also in endoneurial vessels. Finally, TN was detected in the perineurium and the nodal/paranodal region in control nerve, while in some cases of CMT1 and CIDP it appeared to mark several internodes. These data, showing specific changes of the ECM components in peripheral neuropathies, suggest that a complex ECM remodeling is associated with mechanisms of nerve damage and repair. Supported by MURST‐COFIN 98 (n°86) and by CNR 98 (n°03081 CT04).

Collagen for neural tissue engineering: Materials, strategies, and challenges

“…Unlike the CNS injury, the distal portion of axons and myelin detritus are lysed and eliminated due to the activation of Schwann cells and the recruitment of macrophages, paving the way for removing inhibitory factors [ 16 ]. Notably, Collagen I, III, IV, V, VI and laminin exhibit significantly elevated deposition in Schwann and perineurial cells during peripheral injuries and neuropathies [ 17 ].…”