This document provides an overview of interventional approaches for treating low back pain caused by intervertebral disc degeneration. It describes the anatomy and physiology of the intervertebral disc and the causes and stages of disc degeneration. Gene therapy approaches including delivery of anticatabolic genes like TIMP-1 are discussed as a way to inhibit the enzymes that degrade the disc matrix. Growth factors like BMPs, PRP, and EGF are also reviewed for their ability to stimulate matrix production. Cell-based therapies using nucleus pulposis cells or stem cells aim to regenerate the disc extracellular matrix.

1. A GLIMPSE OF THE NOVEL
INTERVENTIONAL APPROACHES
Babak Ashrafnejad MD
Pain Fellowship
Anesthesiologist

2.  Low back pain is a disorder that affects a considerable
proportion of the population
 About 60–80% of all people suffer from back pain at
some time during their life
 Degeneration of the intervertebral disc (IVD) and disc
herniation are two distinct but related causes of low
back pain and radicular pain, respectively

3.  At least 40% of patients with chronic low back pain
showed characteristics of intervertebral disc
degeneration (IVDD)
 IVDD is an aberrant, cell-mediated response to
progressive structural failure

4. ANATOMY

6.  Fibrocartilaginous tissues that allow motion
between the vertebral bodies
 They transmit load and absorb the shocks
 Each IVD is composed of three distinct but
connected structures:
 The Endplate
 The NP
 The AF

8.  Endplates consist of hyaline cartilage and occupy the
inferior and superior interfaces between the
intervertebral disc
 Collagen is greatest at the periphery of the endplates,
while the centre contains most of the proteoglycans
and water
Collagen
Proteoglican
+Water

9.  They have approximately 1-mm-thick horizontal layer
of hyaline cartilage
 Early in life : the endplates are highly vascularized
 First year : The degree of vascularity wanes dramatically
 Third decade : No blood vessels present

11.  Encases the NP and prevents the it from herniating
 The AF is composed of :
 Water (65–90% of its weight)
 Collagen type I and II fibres (60% of dry weight)
 Proteoglycans and other proteins (10–20% of dry
weight)
The AF is composed of 15–25 loosely connected concentric rings of highly organized collagen fibres
(lamellae)

12.  Has a cell density of 9×106/cm3
 Only at the outer layer, there is sensory nerves
 Nutrition of the IVD is based on diffusion of
nutrients through the subchondral bone and
the endplates to the disc

14.  Much less dense and nearly the consistency of
a gel.
 Gel contains :
1- Type II collagen and elastin. These hold the gel-
like area
2-Proteoglycan molecules that have hydrophilic
chondroitin and keratin sulfate attached to
them.
3- Water > 90%

15. Water
Molecules
proteo
glycan
Collagen fibers

19.  Is the disc framework structure
 Composed of collagen and aggrican
 Makes disc components more strenght (anchor)
Matrix
Chodrocytes
Collagen
fibers

20. 1, intervertebral
Disc
2, posterior longitudinal ligament
3, spinal nerveroot
4, vertebral body
5, segmental artery
6, interosseous arteries
7, dorsal root ganglion with
accompanying blood vessel
8,descending branch of the sino-
vertebral nerve
9, ascending branch of the sino-
vertebral nerve
10, aorta

21. 1, intervertebral disc
2, recurrent sino-vertebral nerve
3, spinal nerve
4, posterior branch of spinal nerve
5, thecal sac with spinal roots
6, paraspinal muscle

22. DISC DEGENERATION

23.  Body weight
 Lifting strength
 Ageing
 Occupational risks, such as exposure to vibrations
 Smoking and atherosclerosis causing decrease in
nutrient supply
 Tissue weakening, which primarily occurs due to
inherited genetic factors
 Nutritional compromise
(Adams and Roughley, 2006)

24. catabolic processes exceeding anabolic ones
morphological changes, cell transformations and degeneration
loss of proteoglycans and a decrease in water content of the NP
Degeneration of the endplates impairs transport of nutrients into the
disc and results in the accumulation of waste products such as
lactic acid, which reduce the pH
reduce the number of cells / reduction of extracellular matrix (ECM)
synthesis

25. Dehydration of the NP
Reduced shock absorbance capacity
Loads will be transferred to the AF
Ruptures or cracks of the AF

28.  Fibrosis
 Narrowing of the disc space
 Diffuse bulging of the annulus beyond the disc
space
 Extensive fissuring
 Mucinous degeneration of the annulus
 Defects and sclerosis of the endplates
 Osteophytes at the vertebral apophyses

29. DISC
REGENERATION

30.  Anticatabolic agents
 Growth factors
 Gene Therapy
 Cellular components
Np cell transplantation
Stem cell Therapy
 Scaffolds

31. ANTICATABOLICS

32.  The MMP (Matrix-Metalloproteinase) enzyme
family are responsible for the degradation of :
Collagen
Aggrecan
Versican
 Within the matrix, MMP activity is normally
inhibited by TIMPs (Tissue Inhibitor of
Metolloproteinase)

33.  MMPs & TIMPs are balanced in normal discs
 When imbalance Degeneration
 Four TIMPs (TIMP-1, TIMP-2, TIMP-3, and TIMP-4)
have been identified in discs.
 Application of TIMPs for treatment of DDD through
gene therapy or direct protein application (is still in an
early phase of development)

34.  ABSTRACT
 Cells from degenerated intervertebral discs were transduced with an adenoviral vector delivering cDNA of the catabolic
inhibitor, TIMP-1, and alterations in the measured proteoglycan were assessed.
To assess the potential of TIMP-1 to favorably modify the proteoglycan content of degenerated intervertebral disc cells.
Gene therapy with anabolic factors has resulted in increased proteoglycan synthesis in intervertebral disc cells.
Biochemical analysis of degenerated discs has revealed elevated levels of the catabolic enzymes, matrix
metalloproteinase, suggesting an intimate role of these factors in the degenerative process. The use of TIMP-1, an
endogenous inhibitor of matrix metalloproteinase, via gene therapy may provide an additional method to alter the
degenerative processes occurring in the intervertebral disc.
Degenerated intervertebral disc were isolated from eight patients undergoing elective surgical procedures. Cells were
cultured in monolayer and transduced with different concentrations of either an adenoviral-tissue inhibitor of
metalloproteinase-1 (Ad-TIMP-1) or adenoviral-bone morphogenic protein-2 (Ad-BMP-2) construct. Cells were cultured
in a three-dimensional pellet and proteoglycan synthesis was assessed via 35S-sulfur incorporation.
Gene delivery of TIMP-1 and BMP-2 increased measured proteoglycan synthesis at each concentration assessed. IVD
cells treated with Ad-TIMP-1 demonstrated an optimal response at a multiplicity of infection (MOI) of 100. Cells treated
with Ad-BMP-2 demonstrated a progressive increase in proteoglycan synthesis with increasing viral concentrations.

Successful delivery of the anticatabolic gene, TIMP-1, results in
increased measured proteoglycan in cultured degenerated disc
cells. This finding supports catabolic inhibition as a promising
avenue of research for the treatment of degenerative disc disease
via gene therapy.
Wallach C J .et al. Spine , Oct 2003

35. IL-1 and TNF have been shown to mediate the
inflammatory cascade in discs and
contrariwise,
anticatabolic agents, such as inhibitors of IL-1 &
TNF have been shown to be
chondro-protective

37.  Disc degeneration diagnosis based on history,
physical exam and Imaging studies.
 Positive discography ( VAS>6 at <50psi above
opening pressure)
 Intradiscal etanercept injection

38.  Sainoh et al. 2014 Intradiscal etanercept inj. (RCT) (10
mg)
Results : positive response
 Cohen et al. 2007. Intradiscal etanercept inj. (RCT)
(0.1-1.5 mg)
Results : no positive response
 Cohen et al. 2009. Transforaminal epidural etanercept
injection (RCT) (2-6 mg)
Results : is superior to systemic application in sciatica
pain relief

39. GROWTH FACTORS

40.  Growth factors bind to cell membranes(receptors)
activation of an intercellular signaling cascade
exert biological effects, such as :
1- Stimulates cell proliferation, differentiation, migration
2- Regulates matrix production and repair

42.  Autologous Platelet-Rich-Plasma (PRP)
 Platelet derived transforming growth factor-
13 (TGF-I3)
 Epidermal growth factor (EGF)
 Osteogenic protein-l (OP-l) also known as
bone morphogenic protein-7 (BMP)
 LIM mineralization Protein 1 (LMP1)
 Link N
 SOX-9

43.  EGF : increases in matrix synthesis and cell
proliferation
 TGF-I3I : matrix synthesis alone (TGF-I3I)‘
 Increases in matrix synthesis with TGF-131 is
dramatic.
 Osteogenic protein-l (OP-l) into rabbits resulted
in mild increases (12%-15%) in disc height up
to 8 weeks following injection

44.  BMPs are members of the TGF super family
 Stimulates cells to express a more chondrocytic
phenotype
 Increase cell proliferation, and collagen Type II
synthesis, aggrecan

45. Gene Therapy

46. transfer of ‘‘the gene of interest “ (RNA,DNA)
into the target cells using a so-called vector
(Virus, main cells)
produce the desired gene products (RNAs or
proteins) in a continuous fashion
Regeneration

47. 1- Virus Vectors (Adenovirus/ Retrovirus)
2- Non viral Vectors (direct gene transfer)
Vectors
Gens
Target Cell
Continuous
Production
RNA
DNA
Continuous
Biological Effects

48. Vector binds to
cell
memebrane
DNA injected to vector
Vector is packaged
in vesicle
Vesicle breaks
down releasing
vector
Cell makes
protein using
new gen
Vector
(Adenovirus)
Vector injects new
gen into nucleous

49. Microbubbles Ultrasound Gene Therapy

50. NUCLEUS PULPOSIS CELL
TRANSPLANTATION

51.  Autologous reinsertion of the NP from normal
disc to degenerated one has been shown to :
 Delay degeneration of the disc, including the
AF, NP, and endplate
 Restoration of disc height
 Retard disc degeneration in vivo
 Increases production of collagen 2
 No host-versus-graft response

53. Reimplantation of disc cells from discectomy
specimens in a nonrandomized series of
human patients demonstrated MRI scan
improvements consistent with increased
proteoglycan matrix within the NP and relief of
symptoms

54. STEM CELL
THERAPY

55.  MSCs and bone marrow stem cells (BMSC) are
the main stem cells
 Readily available source of autologous cells,
with minimal donor-associated complications
 Adipose tissues are good source of stem
cells(ADSC)

56.  MSCs differentiated into cells expressing a
chondrocyte-like phenotype (NP cells)
 with increased production of :
matrix components, such as
Aggrecan
Collagen Type II

57.  There are two main strategies for acquisition of
these desired somatic stem cells:
 Embryonic stem cells (ESCs)
 from the fat or bone marrow

58. Stem Cell Therapy Procedure no general
anesthetics are used.
The out-patient procedure takes about 3-4
hours:

59.  1. Collection of adipose tissue by tickle lipo,
centrifugal separation of stem cells
 2. Collection of bone marrow aspirate from
the posterior iliac crest, centrifugal separation
of stem cells
 4. Injection of the cells into the affected site
under x-ray fluoroscopic guidance

60. to your disc

61.  Yoshikawa et al , 2010
 percutaneously grafted MSCs into degenerated IVDs in two
women aged 67 and 70 years.
 After two years, both individuals had alleviation of symptoms and
radiographic changes
 Haufe et al., 2006
 intradiscal injection of hematopoietic stem cells into ten patients
 none of these individuals had any relief of symptoms

62. SCAFFOLDS

63. The purpose of a cellular scaffold is to provide an
optimal microenvironment
for
cellular migration and proliferation
that allows the cells to maintain the appropriate
phenotype

65.  Collagen is a physiological biomolecular
scaffold (collagen gels)
 hyaluronan acts as an anchor for aggrecan
retention
 Chitosan-based polymers a soluble polymer at
room temperature, and induced to gel at body
temperature

66.  Polyglycolic acid, polylactic acid
 copolymers
 Bioglass
 Poly ε-caprolactone (PCL)
 Polyurethanes
 Silk (natural biopolymer)

67. BIOMATERIALS

68.  Two broad categories :
 polymers that are preformed
 polymers that are formed in situ

69.  Injectable
 Require minimally invasive procedure
 Radiopaque
 The mechanical properties of polymers:
Viscoelasticity
Toughness
Permeability
Conformable structure

70.  Flowable materials may be injected via a small
incision, allowing minimally invasive access to
the disc space
 Derived from silk and elastin
 Mimics the protein content, water content, pH
of the natural nucleus pulposus
 Indications : early stages of Degenerative Disc
Disease (DDD) and as an adjunct to
microdiscectomy