Biology Reference
In-Depth Information
tendinopathies of the shoulder by the disintegration of calcified deposits, and
shortly afterward shock wave treatment was introduced into other fields of
medicine. ESWT has become a widely utilized therapeutic tool in regener-
ative medicine in recent years. It is frequently and successfully administered
in painful conditions such as humero-radial epicondylitis (tennis elbow),
plantar fasciitis, and other pathological conditions affecting bone-related
structures. Chronic wounds, ulcerations, and ischemic heart failure have also
been successfully targeted by ESWT (
Mittermayer et al., 2012; Nishida
et al., 2004; Zimpfer et al., 2009
).
In this review, we focus on the use and effects of defocused low-energy
ESWT in the peripheral nervous system.
2. FEATURES OF PERIPHERAL NERVE REGENERATION
IN RODENTS AND HUMANS: HOW TO
SPEED UP SLOW REGENERATION?
Injuries to peripheral nerves are followed by a rapid process of degen-
erative events called Wallerian degeneration. These events include changes
that are effective in the anterograde direction from the injury site, that is, the
disconnection of axons from the target organ, for example, the motor end-
plate, the breakdown of axon and myelin in the distal stump of the injured
nerve, and changes that affect the proximal nerve stump (degeneration up to
the first Ranvier node) and mainly the cell body retrograde from the injury:
chromatolysis (the classical term for the disintegration of the rough
endoplasmatic reticulum), dislocation of the nucleus, and shrinkage of the
dendritic tree. The degenerative processes are followed by regenerative
events, provided that the injured nerve stumps are in close vicinity and
the regenerating axons from the proximal stump are able to enter the vacated
endoneural sheaths in the distal stump. The regrowth of axons is supported
by the rapid proliferation of Schwann cells in the distal stump providing a
contact guide for them. The proliferating Schwann cells align to form the
bands of B¨ngner and restructure the extracellular matrix that contains
growth-promoting molecules such as laminin and fibronectin. The growth
cone of the regenerating axons actively synthesizes transmembrane integrin
molecules, for example, integrin-type alpha5-beta1, which interacts with
fibronectin, thereby ensuring the axonal growth. In this way, all the condi-
tions required for the successful regeneration and reinnervation of the targets
are provided.
