Assessment of immunologic, proangiogenic and neurogenic properties of human peripheral nerve epineurium for potential clinical application.

The epineural sheath is a promising naturally occurring material for enhancement of peripheral nerve regeneration. Based on a literature search there is a limited number of reports on the biological and immunological properties of human epineurium. The goal of this study was to assess, using immunocytochemical methods, the immunological (HLA class I and II antigens, T lymphocytes, macrophages), proangiogenic (VEGF, CD31), and neurogenic (GFAP, S-100) properties of human epineurium isolated from ilioinguinal nerves (n=19) taken from deceased donors, and from sciatic nerves (n=12) taken from limbs amputated due to critical ischemia. Our studies confirmed reduced expression of HLA class II antigens on the infiltrating cells, a reduced number of T lymphocytes, and greater vessel density in the epineurium obtained from deceased organ donors. Macrophages were more abundant in the epineurium isolated from the amputated limbs. We found that the epineurium harvested from peripheral nerves of the deceased donors showed negligible immunogenic and increased proangiogenic properties compared to the epineurium of nerves taken from amputated limbs. These findings support the rationale to use human epineurium obtained from deceased donors as a new biological material for enhancement of peripheral nerve repair for potential clinical application in regenerative medicine.