Autonomic Nervous System Repair and Regeneration

Abstract

The autonomic nervous system is a component of the peripheral nervous system involved in visceral functions and divided into three distinct components: sympathetic, parasympathetic, and enteric nervous system. All these divisions are made up of afferent and efferent fibers providing sensory input to the central nervous system and motor output through motor visceral nerves. Similarly to the somatic nervous system, lesions affecting the autonomic nervous system are very frequent and, depending on the degree of severity, result in a complete or partial loss of functionality of the visceral organ involved. Given the anatomical location, most autonomic nerve lesions are classified as iatrogenic injuries caused by possible complications in various medical treatments, drug administration, injection, radiation, traction during preoperative patient positioning, and surgical procedures. This review provides an overview of the most frequent iatrogenic autonomic nerve lesions occurring during substantial surgical procedures, prostatectomy, hysterectomy, and heart transplantation. In addition, the main factors that influence and characterize nerve regeneration in the autonomic nervous system will be discussed and a particular focus on the importance of in vitro and ex vivo models, which allow extrapolation of important data in the study of such regeneration, will be provided. Finally, an overview of the main scientific evidence that testifies to neurogenesis in the enteric nervous system will be provided, where some changes, following several types of nerve damage and injuries, in cell signaling molecules are thought to have neurogenic properties in the gut.