Lecture 12 - Regenerative & Biological Therapy Flashcards
What is regenerative medicine?
Branch of translational research which deals with the process of replacing, engineering, or regenerating human cells, tissues, or organs to restore normal function.
Do products currently available in veterinary medicine actually “regenerate” tissue during healing?
Usually, no.
Remains unclear or unproven in many applications.
What are most currently available regenerative therapies aimed at?
- Reducing inflammation
- Promoting neovascularization
- Modulating and promoting an anabolic local environment during healing.
What are currently available regenerative therapies NOT aimed at?
Direct regeneration of tissue via direct inoculation of a stem cell.
What is a better term than “regenerative therapies” for the therapies that are currently available?
biological therapies
Predominant indication in small and large animal medicine is the treatment of _____.
musculoskeletal disease
What 2 aspects of musculoskeletal disease are biological therapies most used for?
- Joint/osteoarthritis
- Tendon and ligament injury
What additional areas have ongoing research in veterinary medicine?
- Pulmonary repair
- Oncology and cancer therapy
- Dermatology
What does IRAP mean/stand for?
Autologous Conditioned Serum
What does PRP stand for?
Platelet Rich Plasma
What does “pro-stride” mean?
Autologous Protein Solution
What are 4 locations from where we can get stem cells?
- Bone marrow aspirate concentrate
- Bone marrow-derived MSCs
- Fat/Vascular Stromal Fraction MSCs
- Autologous vs. Allogenic
What is autologous conditioned serum (IRAP) widely used for?
Equine sports medicine (for the last 15-20 years)
What does IRAP mainly use in its MOA?
Cytokines
What are cytokines and what are the 2 general types?
Proteins within mammals that are secreted by various cells of the immune system that influence an effect on another cell.
Types = Pro-inflammatory and Anti-inflammatory
What is the most common and central pro-inflammatory cytokine?
IL-1
How is IL-1 involved in osteoarthritis?
It is upregulated in the joint and increases proteolytic enzymes (matrix metalloproteinases) which degrade type-2 collagen in articular cartilage.
What is one anti-inflammatory cytokine involved in IRAP and what is another name for it?
IL1-ra; AKA IRAP protein
Where does IL1-ra originate from?
monocyte cells in the blood
What does IL1-ra bind to and why?
Binds to IL-1 receptors to block cellular signaling of inflammation.
What does IL1-ra circulating in the blood do?
Normal amounts of circulating IL1-ra helps provide balance between anabolic (build/restore) and catabolic (breakdown) processes in the body.
IRAP binds to _____, preventing _____ binding which would cause _____.
IL-1 receptors, IL-1, inflammation
How do we capitalize on IL1-ra as a biological therapy?
Collect whole blood from animal. expose it to select surfaces to stimulate monocytes to secrete IL1-ra.
How can blood monocytes be stimulated to secrete IL1-ra?
- Borosilicate or chromium sulfate glass beads in a syringe
- Held at body temp (37.5 deg C) for up to 24 hours
- Centrifuged and serum aspirated off
How much more IL1-ra vs. IL-1 does manipulated serum have at 24 hours (i.e. what is the IL1-ra to IL-1 ratio)?
6-10x more IL1-ra vs. IL1
How can autologous conditioned serum be used to influence inflammation?
It can be aseptically injected back into a joint compartment.
How often are autologous conditioned serum injections repeated?
Every 2 weeks for 3-4 treatments
What can be done with leftover IRAP serum?
Can be frozen for future use
Platelets are most commonly associated with _____ and _____. They are also a rich source of _____.
clotting, hemostasis, growth factors
What are growth factors?
Proteins that stimulate growth, proliferation, healing, or cellular differentiation in cells.
What do platelets contain within their cellular architecture?
alpha granules
What are alpha granules?
Storage centers for growth factors
What are some examples of sub-types of common growth factors?
- PDGF (platelet-derived growth factor)
- TBF-β (transforming growth factor beta)
- VEGF (vascular endothelial growth factor)
- IGF-1 (insulin -like growth factor)
- EGF (epidermal growth factor)
What 3 things do all growth factors have a global role in promoting?
- Cell migration, proliferation, differentiation
- Angiogenesis/neovascularization
- Matrix/scaffold synthesis for tissue ingrowth
What is platelet-rich plasma?
A blood-derived therapy that focuses on enriching the plasma substrate from whole blood with growth factors released from platelets.
What are the 2 different methods of preocessing of PRP and which one is more common?
- Centrifuge based (more common)
- Filtration based
What are the steps to making PRP?
- Collect whole blood mixed with an anti-coagulant
- Initial centrifugation spin - separates RBC from buffy coat and plasma
- Second centrifugation spin - separates platelets from majority of plasma
Most PRP kits result in _____ platelets per ml.
>1000 x 103
What do some PRP kits use to stimulate release of growth factors from alpha granules?
Calcium chloride or bovine thrombin
How is PRP used in the patient?
Injected into the site of injury
What can we do with unused PRP?
Freeze it and thaw at future use
In large animal (equine), PRP is predominantly used for _____.
soft tissue injury
What are some specific examples of uses for PRP in equines?
Tendon or ligament sprain/complete tear of fibers
PRP is often injected under _____ guidance.
ultrasound
What is the predominant use for PRP in dogs?
Intra-articular injection in management of osteoarthritis
What is the market name for autologous protein solution?
Pro-stride
What is autologous protein solution?
Combo of PRP and ACS
The first step in processing APS is identical to _____.
PRP
What does the 2nd processing step of APS do? What does it do for veterinarians?
Upregulates IL1-ra without the need to incubate serum;
Makes APS therapy more “point of care” for vets
What are stem cells?
Biological cells that differentiate into other types of cells.
Stem cells can also divide to produce more of the _____ of stem cell.
same type
What are the 2 types of stem cells?
- Embryologic
- Adult
Adult stem cells act as a _____ in the body, and are located in various _____.
repair system, tissues
What 3 locations in the body have adult stem cells?
- Bone marrow
- Fat
- Blood
What are autologous stem cells?
Stem cells collected from the same patient to be treated.
What are allogenic stem cells?
Collected from a donor animal and administered into a recipient patient.
(Donor and recipient are the same species)
Concentrate aspirated from bone marrow contains _____ of stem cells within the cellular fraction.
<1%
What is the significance of BMAC containing <1% of stem cells?
There is limited ability to directly aspirate bone marrow and then re-administer the concentrate with true stem cell benefit
What can we do with BMAC to ensure a true benefit? How much does this increase the cell content and how long does it take?
Send to a lab to be cell cultured; increases SC content up to 15-30 million cells - takes 3-4 weeks
From where can we get bone marrow aspirations and what instrument is used?
Sternum, tuber coxae, humerus (dogs);
Jamshidi needle under sterile technique and local block
What is another name for adipose stem cells?
Stromal Vascular Fraction
What is the difference between stromal vascular fraction and BMAC?
SVF has a significant increase in stem cells compared to equal amounts of BMAC;
BUT amount available for therapy (<1 million) is significantly less than culture expanded bone marrow stem cells (15-30 million)
How many stem cells per 50g of tissue are latent in SVF?
500-750,000
_____ therapy remains the largest perceived benefit of adipose stem cells over bone marrow.
Point of care
Where is fat harvested for adipose stem cells and how?
Base of tail head and inguinal region;
Direct excision through skin incision, liposuction using repetition of needle aspiration
Both bone marrow and fat derived stem cells are often utilized as _____ therapy.
autologous
What is the largest hinderance to using allogenic stem cells?
Risk of immune reaction to administered allogenic SCs
What are allogenic sources of SCs?
- Dental pulp
- Umbilical
- Amniotic
What are the common routes of administration for stem cells?
- IV and intra-arterial via tourniquet and regional limb perfusion
- Direct admin into site of injury/lesion (U/S guided)
- Intra-articular injection
