Regenerative Medicine in Chronic Pain Management

Regenerative technologies are the future of medicine. The current clinical strategy focuses primarily on treating the symptoms but regenerative medicine seeks to replace tissue or organs that have been damaged by age, disease, trauma, or congenital issues.

1. ROLE OF REGENERATIVE MEDICINE IN CHRONIC PAIN MANAGEMENT
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2. STEM CELLS
❑Stem cells (SCs) are immature cells capable of self-renewal and differentiation
into functional cell types.
❑Fundamental criteria of SC classification involve their origin (embryonic- or
adult tissue-derived) and differentiation potency, which indicates the potential
lineages to which a given cell can mature.
❑The most extensively studied types of SCs include mesenchymal stem/stromal
cells (MSCs), induced pluripotent stem cells (iPSCs) and embryonic stem cells
(ESCs).
❑MSCs are adipogenic, chondrogenic and osteogenic and they have become a
promising strategy for treating bone, cartilage and muscle injuries.
❑MSCs are easily accessible, biologically safe and have low immunogenicity
makes them remarkable option for cell therapy.
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3. REGENERATIVE BIOMATERIALS
❑Bioactive ceramics; natural polymers such as chitosan, hyaluronic acid and
collagen
❑Synthetic polymers such as polycaprolactone (PCL) and poly(lactic-co-glycolic
acid) (PLGA)
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4. ROLE OF REGENERATIVE BIOMATERIALS
❑Regeneration of bone, cartilage and nerve
❑Providing a microenvironment that augments the regenerative potential of
both the transplanted and host cells
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5. BIOMATERIAL AND REGENERATIVE MEDICINE
❑Regenerative therapies repair degenerated tissues
❑Pain management biomaterials serve as drug carriers
❑Biomaterial scavengers remove proinflammatoryreactive oxygen species
❑MSCs have antiinflammatory, analgesic and regenerative properties.
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6. Scaffold pore architecture Alignment of extracellular molecule hydrogels
Bioengineering functional skeletal muscle tissues by the 3D
printed dECM-based structures with topographical cues
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7. CONTROLLED RELEASE OF REGENERATIVE THERAPEUTICS
Direct injection of GFs or PRP without a delivery system results in significant
loss of the therapeutic agents due to leakage, diffusion, denature, and
circulatory clearance.
❑Matrilin-3 (OA)
❑Advanced composite systems composed of hyperbranched polymer, PLGA
nanoparticle, and spongy PLA microsphere (IVD)
❑Branched poly(ester urea) (PEU) nanofibers (RCS)
❑Heparin via factor-1α& factor-5 (IVD)
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8. INJECTABLE SCAFFOLDS
❑Proposed for tissue repair and localized
drugs
❑Using gel matrices and nano- or
microparticles
❑The injectability of tissue engineering
scaffolds can reduce the tissue damage
caused by the transplant surgery, simplify the
procedure, and lower the cost.
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Ligorio C, O'Brien M, Hodson NW, Mironov A, Iliut M, Miller AF, Vijayaraghavan A, Hoyland JA, Saiani A. TGF-β3-loaded graphene
oxide-self-assembling peptide hybrid hydrogels as functional 3D scaffolds for the regeneration of the nucleus pulposus. Acta
Biomaterialia. 2021 Jun 1;127:116-30.

9. THE INTERNATIONAL SOCIETY FOR CELLULAR THERAPY
(ISCT) DEFINITION FOR MSCS
❑MSCs are defined as fibroblast-like, plastic-adherent cells able to self-
renew, possessing a specified multiantigenic phenotype that includes a lack of
expression of several surface markers (CD11b, CD14, CD19a, CD34, CD45,
CD79 and HLA-DR) with the abundant presence of selected antigens, including
CD29, CD44, CD73, CD90, CD105 and CD166 (Horwitz et al., 2005).
❑MSCs are biologically similar but cell origin may determine their specified
characteristics and functional properties (AT-MSCs had the highest colony
formation capacity and UC-MSCs possessed superior chondrogenic potential)
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10. ROLES OF MSCS
❑Regenerative strategy for bone tissue repair
❑Modulation of several endogenous processes of tissue repair and immune cell
functions
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11. TISSUE SOURCES OF MSCS
❑BM and adipose tissue (AT) being the most prevalent (Elahi et al., 2016)
❑Peripheral and menstrual blood (Pouryazdanpanah et al., 2018; Rossignoli
et al., 2013)
❑Cord blood (Sibov et al., 2012)
❑Dental pulp (Labedz-Maslowska et al., 2020)
❑Skin (Castro-Manrreza et al., 2019)
❑Umbilical cord Wharton's jelly (UC) as a most recognized rich source (da
Silva Meirelles et al., 2006)
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13. CLINICAL APPLICATIONS OF MSCS
❑Due to their high proliferative capacity, ability to differentiate into several types of
tissues and abundant secretion of paracrine factors, including those with
immunomodulatory properties, MSCs have become the primary cells of choice for cell
therapy (Ayala-Cuellar et al., 2019).
❑As MSCs are cells with limited ‘stemness’ potential, their utilization carries no
considerable risk of teratoma formation when compared with ESCs (embryonic stem
cells) or iPSCs (Induced pluripotent stem cells ) (Mahla, 2016).
❑Due to the low expression of MHC molecules, MSCs are considered low immunogenic
and immunoprivileged and they can be used in the allogeneic system. (Ayala-Cuellar et
al., 2019)
❑Recent data also demonstrated that several factors, including pretreatment conditions
or route of administration, may affect the immune response against allogeneic MSCs,
which should be considered when planning MSC-based therapy (Schu et al., 2012).
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14. MSC-EVS AS ALTERNATIVES FOR CELLBASED THERAPY
Transplanted MSCs may facilitate tissue regeneration not only through their
direct contribution to newly formed tissue due to the processes of proliferation
and/or differentiation but also, or even predominantly, via their paracrine
activity influencing cells residing in the site of injury (Gnecchi et al., 2005;
Timmers et al., 2008).
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15. EVS CLASSIFICATION AND NOMENCLATURE
❑EVs are a heterogeneous population of membrane-enveloped structures
released from the surface of cells (Sedgwick & D'Souza-Schorey, 2018).
❑They are secreted by normal cells, as well as cancer and apoptotic cells, and
their presence has also been detected in several body fluids, including saliva,
urine, milk and amniotic fluid (Balbi et al., 2017; Foster et al., 2016).
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16. SEVS
❑SEVs originate from various sources, including the nervous system (neurons
and glial cells), peripheral tissue cells, body fluids, and immune cells.
❑The transfer of cargo molecules between injured and recipient cells via sEVs
holds immense potential in reprogramming the phenotype of the latter,
thereby enabling them to acquire new functions.
❑Selective encapsulation of specific cargo molecules within EVs facilitates
precise regulation of inter-tissue interactions, thus achieving fine-tuned control
over physiological and pathological processes.
❑Moreover, the protective nature of sEVs shields their cargo molecules from
degradation and dilution, facilitating efficient transmission of molecular
information between cells and tissues.
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17. SEVS BIOGENESIS AND SIZE
❑Exosomes (Exos): 30 to 120-150 nm
❑Microvesicles (ectosomes, or microparticles) (MVs): 50 to 1000
nm
❑Apoptotic bodies (ABs): exceeding 1000 nm
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18. ❑sEVs offer no immunogenicity and lack neoplastic qualitiesor
differentiation concerns.
❑MSC-sEVsare abundant in supply, easy to preserve, and possess
theability to cross biological barriers with ease, such as BBB.
❑sEVs can protect contents against degradation,such as miRNA.
❑Provide multiple delivery modes, making them highly versatile.
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19. EXOSOMES
❑Exosomes are classified as a group of EVs ranging in size from 30 to 120
nm.
❑They are secreted by exocytosis as a result of the fusion of multivesicular
bodies (MVBs) with the cell membrane.
❑Exosomes are enriched in proteins from the tetraspanin and heat-shock
protein family, as well as in proteins involved in endosomal sorting and
transport.
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20. ECTOSOMES
❑Ectosomes, also known as microvesicles, are larger vesicles with diameters of
50 nm to 1 μm.
❑They are released from the cell surface by membrane protrusions and
rupture of the cortical cytoskeleton, leading to the formation and detachment
of vesicles in the process of budding.
❑They are enriched in selectins, integrins, phosphatidylserine and a number of
other membrane molecules characteristic of the cells from which they originate.
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21. DEFINITION OF PAIN
The International Association for the Study of Pain (IASP) defines pain as an
unpleasant sensory and emotional experience associated with, or resembling
that associated with, actual or potential tissue damage.
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22. CHRONIC PAIN
❑Nociceptive
❑Neuropathic
❑Nociplastic (diffuse sensitization, and functional visceral pain)
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23. WHO LADDER
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24. OPIOIDS
❑Between 21 and 29% of patients taking opioids for chronic pain misuse their
opioids.
❑Approximately 10% develop opioid use disorder.
❑Opioid overprescribing for pain is considered an initial driving factor for the
Opioid Epidemic.
Vowles, Kevin E.a,*; McEntee, Mindy L.a; Julnes, Peter Siyahhana; Frohe, Tessaa; Ney, John P.b; van der Goes, David
N.c. Rates of opioid misuse, abuse, and addiction in chronic pain: a systematic review and data synthesis. PAIN
156(4):p 569-576, April 2015. | DOI: 10.1097/01.j.pain.0000460357.01998.f1
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The revised WHO analgesic ladder Contributed by Marco Cascella, MD

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27. NEUROPATHIC PAIN
❑Neuropathic pain is caused by a lesion ora disease of the somatosensory
nervous system (It affects 7%–10% ofthe population).
❑The main symptoms are shooting pain, hyperalgesia, allodynia, numbness
and paresthesia, which are not adequately relieved by standard analgesics.
❑The first line therapy of neuropathic pain are tricyclic antidepressants (TCAs),
the 5-HT–noradrenaline reuptake inhibitor (SNRI) antidepressants duloxetine
and venlafaxine, pregabalin, gabapentin and gabapentin ER/enacarbil.
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28. ❑In neuropathic pain models, MSCs are usually injected intravenously (i.v.) or
intrathecally.
❑The immediate IV administration of MSC in animal models of nerve injury
resulted in a significant improvement in neurobehaviour, electrophysiological
function and myelination of animal axons (chemokine CXCL12 (SDF-1α)effect).
❑Intravenous MSC injection also reduced mechanical and thermal
hyperalgesia and allodynia and restored CatWalk XT gait parameters in CCI
rats.
❑The analgesic effect of MSCs was related to their anti-inflammatory action
(through IL-1β,TNF-αand synaptophysin and IL-10 and iNOS)
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30. MODIFIED MSCS ARE MORE POTENT!
❑Sirtuin 1 (SIRT1)-modified MSCs
❑human proenkephalin (hPPE) gene-modified MSCs
❑FGF1 gene-transfected adipose-derived MSCs (development, angiogenesis, neurogenesis,
adipogenesis and wound healing)
❑Magneto-cell therapy, a novel approach to pain management (combination
of MSCs and a pulsed magnetic field that increases the thermal nociceptive
threshold) (?)
Transfection is the process of introducing nucleic acids into eukaryotic cells by nonviral methods.
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32. THE EFFICACY OF MSCS DEMONSTRATED IN
❑Chemotherapy induced neuropathy (oxaliplatin/ IV Inj)*
❑Burn-induced neuropathy (SC Inj)**
❑Crush injury-induced neuropathic pain (epineural and intraneural
administration of AT-MSCs)***
❑SNLneuropathicpainratmodel(intrathecal administration of MSC-derived
exosomes)****
*DiCesareMannellietal.,2018
**Lin et al., 2018
***H.Y.Leeetal.,2015
****Shiue et al., 2019
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33. SPINAL CORD INJURY
❑Clinical symptoms of SCI include motor deficits, neuropathic pain and
impaired sensory and autonomic functions.
❑Post-traumatic degeneration is largely caused by a secondary injury cascade
that includes nerve disconnection, inflammation, blood–brain barrier
dysfunction, lipid peroxidation, neuronal death, apoptosis and necrosis.
❑Early surgical intervention may help reduce negative effects (?) (Grassner et
al., 2016)
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34. ❑MSCs transplanted directly to the lesion, in both allogeneic and xenogenic
systems, alleviated pain and allodynia in SCI animal models (Yousefifard et
al., 2016).
❑MSCs and amniotic epithelial SCs reduced mechanical allodynia but not
thermal hyperalgesia (Roh et al., 2013).
❑MSCs from mouse BM improved animal motor functions and reduced
hypersensitivity (Watanabe et al., 2015).
❑NSC-sEV treatment has the potential to reduce neuronal apoptosis, inhibit
neuroinflammation, and promote functional recovery in SCI model rats at an
early stage by promoting autophagy(Rong et al., 2019).
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36. OSTEOARTHRITIS
❑OA is caused by cartilage and subchondral bone degeneration, followed by
synovial membrane inflammation (synovitis).
❑Cartilage has low regenerative properties (because of the lack of
innervation and blood vessels).
❑Conventional OA treatment is limited to pain attenuation and maintaining
joint mobility.
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37. ❑MSCs trigger analgesic effects and inhibit cartilage degeneration.
❑MSCs reduced lameness in horses(Mariñas-Pardo et al., 2018) and dogs
(Yun et al., 2016).
❑In OA dogs,MSCs also increased focal compression strengths of the
affectedcartilage and ameliorated inflammatory changes (Yun et al., 2016).
❑An interesting approach to OA therapy is combiningMSCs with articular
cartilage chondrocytes (via diminishing fibrosis, vascularization and
hypertrophy, promoting cartilage regeneration and augmenting chondrogenic
gene expression) (Prasadam et al., 2018).
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38. ❑MSC-derived exosomes trigger similar analgesic, anti-inflammatory and
protective signalling for cartilage and subchondral bone effects in OA animals
(S. Zhang et al., 2019).
❑Weekly i.a. administration of MSC conditioned medium resulted in the
inhibition of chondrocyte apoptosis, enhancement of autophagy and
maintenance of subchondral bone structure (Chen et al., 2019).
❑MSCs improves cartilage regeneration by augmenting the levels of type II
collagen (Col2), aggrecan and IκBα and diminishing MMP-13, cycloxygenase-
2 (COX-2) and phosphorylated p65 protein (p-p65) (Tang et al., 2015).
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39. ❑MSCs reduces central sensitization and pain by diminishing CGRP levels in
the spinal dorsal horn (Ichiseki et al., 2018).
❑AT-MSCs differentiated into chondrocytes, suggesting the formation of
hyaline-like cartilage (Latief et al., 2016).
❑In in vitro studies, synovial fluid-isolated MSC cultures exhibited good
capacity for chondrogenic gene induction and extracellular matrix synthesis
(Neybecker et al., 2018).
❑MSCs have also been proven to act in an anti-inflammatory manner.
❑MSCs diminish fibrosis, vascularization and hypertrophy in chondrocyte cell
cultures (Prasadam et al., 2018).
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41. OTHER ANIMAL MODELS OF PAIN
❑MSCs have been demonstrated to be beneficial in the interstitial
cystitis/bladder pain syndrome model (Ryu et al., 2018).
❑In a murine incisional hernia model, a fibrin glue mesh covered with MSCs
or their exosomes exerted anti-inflammatory action (enhanced M2
macrophage, IL-4, IL-13 and MMP-2 levels); however, an increase in MMP-9
gene expression was also observed (Blazquez et al., 2018).
❑In a rat noncompressive disc herniation model, intrathecal MSC
administration attenuated pain (diminished mechanical withdrawal threshold),
decreased pro-inflammatory factor levels (IL-1βand TNF-α)and microglial
activation and increased TGF-β1levels in the spinal dorsal horn (Huang et al.,
2018).
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42. ❑Degenerated nucleus pulposus cells co-cultured with adipose tissue-derived
MSCs showed improved matrix synthesis and cell proliferation. Moreover, an
increase in glycosaminoglycan, aggrecan, collagen type II and SOX-9 mRNA
levels, as well as TGF-β1and IGF protein levels, was observed (Song et al.,
2015).
❑MSCs sensitized highly chemoresistant cancer cells to the chemotherapeutic
agent, fluorouracil (Liu et al., 2013).
❑NPC-derived exosomes augment BM-MSC migration and differentiation to a
nucleus pulposus-like phenotype, whereas BM-MSC-derived exosomes enhance
NPC proliferation and matrix synthesis for self repair (Lu et al., 2017).
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44. CLINICAL TRIALS
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46. OSTEOARTHRITIS
❑One of the best studied diseases, which gives the most hope for effective
MSC therapy, is OA.
❑Several clinical trials have shown the safety and efficacy of MSCs from
various sources in OA treatment.
❑MSCs provide overall improvement in joint function, providing improvement
on several scales (Visual Analogue Scale [VAS], International Knee
Documentation Committee [IKDC], Western Ontario and McMaster Universities
Osteoarthritis Index [WOMAC] and Oswestry Disability Index [ODI]).
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47. ❑Intra-articularly administered autologous BM-MSCs provided knee pain
reduction and improvement of the overall quality of life for up to 6 months
(Garay-Mendoza et al., 2017).
❑The i.a. injection of MSCs has beneficial influence on cartilage quality, as
measured by T2 quantitative MRI (Orozco et al., 2013; Vega et al., 2015).
❑BM-MSCs improve meniscal volume and reduce pain (Vangsness et al.,
2014).
❑OA patients reported decreased pain, improved WOMAC scores, decreased
cartilage defects and increased cartilage volume and hyaline-like cartilage
regeneration (Jo et al., 2014; W. S. Lee et al., 2019).
❑No serious adverse effects were observed after i.a. administration.
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48. MSC IMPLANTATION (PARK ET AL., 2017)
❑A human UC-MSC-based preparation called Cartistem implanted in drill
holes in cartilage of the femoral condyle initiated tissue repair (after 12
weeks) and improved the VAS and IKDC scores (after 24 weeks) of OA
patients. The results were stable up to 7 years post-treatment.
❑Mild adverse effects were observed in five out of seven patients (arthralgia,
back pain, bladder distension and elevated antithyroglobulin antibody level);
however, all of them were temporary.
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50. TO BE OR NOT TO BE!
❑Some studies, despite a trend towards improvement, do not reveal any
statistically significant differences between control and MSC-treated OA
patients and even show some adverse effects (such as joint swelling and pain)
(Gupta et al., 2016).
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52. OTHER DISEASES
❑In degenerative joint disease, autologous MSCs improve patient mobility and
overall condition 4–6 years posttransplantation (Elabd et al., 2016).
❑Intradiscal MSC administration in patients with low back pain improved in
VAS, ODI and Short Form-36 (SF-36) scores 1 year after treatment (Kumar et
al., 2017).
❑In chronic lymphoedema, autologous MSC treatment significantly reduces the
ankle circumference and pain, and improves walking ability and an increases
the number of lymphatic capillaries after up to 6 months post-treatment
(Ismail et al., 2018).
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55. ❑Intrathecal implantation of MSCs in patients with early multiple system
atrophy resulted in a dose-dependent reduction in disease progression.
Although the administration was generally well tolerated, higher doses caused
adverse effects (low back/posterior leg pain, associated with
thickening/enhancement of lumbar nerve roots) (Singer et al., 2019).
❑MSCs may also be beneficial in the treatment of necrosis after traumatic
dental injuries (Xuan et al., 2018).
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56. REFERENCES
❑Bryk, M., Karnas, E., Mlost, J., Zuba‐Surma, E., & Starowicz, K. (2022). Mesenchymal stem
cells and extracellular vesicles for the treatment of pain: Current status and perspectives.
British Journal of Pharmacology, 179(17), 4281-4299.
❑Gu, X., Carroll Turpin, M. A., & Romero-Ortega, M. I. (2022). Biomaterials and regenerative
medicine in pain management. Current Pain and Headache Reports, 26(7), 533-541.
❑Kaye, A. D., Edinoff, A. N., Rosen, Y. E., Boudreaux, M. A., Kaye, A. J., Sheth, M., ... & Navani,
A. (2022). Regenerative medicine: pharmacological considerations and clinical role in pain
management. Current Pain and Headache Reports, 26(10), 751-765.
❑Zhang, L., Liu, J., & Zhou, C. (2023). Current aspects of small extracellular vesicles in pain
process and relief. Biomaterials Research, 27(1), 78.
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