Mesenchymal stem-cell based therapies have been
proposed as novel treatments for intervertebral disc degeneration,
a prevalent and disabling condition associated with back pain. The
development of these treatment strategies, however, has been hindered
by the incomplete understanding of the human nucleus pulposus phenotype
and by an inaccurate interpretation and translation of animal to
human research. This review summarises recent work characterising
the nucleus pulposus phenotype in different animal models and in
humans and integrates their findings with the anatomical and physiological
differences between these species. Understanding this phenotype
is paramount to guarantee that implanted cells restore the native
functions of the intervertebral disc. Cite this article:
This article reviews the current knowledge of
the intervertebral disc (IVD) and its association with low back
pain (LBP). The normal IVD is a largely avascular and aneural structure
with a high water content, its nutrients mainly diffusing through
the end plates. IVD degeneration occurs when its cells die or become
dysfunctional, notably in an acidic environment. In the process
of degeneration, the IVD becomes dehydrated and vascularised, and
there is an ingrowth of nerves. Although not universally the case,
the altered physiology of the IVD is believed to precede or be associated
with many clinical symptoms or conditions including low back and/or
lower limb pain, paraesthesia, spinal stenosis and disc herniation. New treatment options have been developed in recent years. These
include biological therapies and novel surgical techniques (such
as total disc replacement), although many of these are still in
their experimental phase. Central to developing further methods
of treatment is the need for effective ways in which to assess patients
and measure their outcomes. However, significant difficulties remain
and it is therefore an appropriate time to be further investigating
the scientific basis of and treatment of LBP.
