Topic 14: PRP Flashcards by Rachel ramella

Young, fecund, robust, inactivated platelets are what size?

1-3 μm discoids

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Humans: Normally ~ platelet count?

150,000-300,000/ml of blood

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platelets life span?

1 week

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α-granules contain? (in platelets)

clotting factors, growth factors, and various other proteins

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Dense granules contain? (in platelets)

ADP, ATP, Serotonin, and Calcium

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Young compared to old platelets size?

Young platelets are large and heavy (dense)

Old platelets are small and light

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Young compared to old platelets aggregation?

Young large platelets aggregate much faster (3-5 x) than older platelets

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Young compared to old platelets ATP and ADP?

Young platelets release dramatically more ATP (4-8 x) and ADP (4-6 x) than do older platelets

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Old platelets to be activated?

Old platelets require substantially greater amounts of ADP to be activated than do young platelets

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Wound –>
Exposes subendothelial collagen –>
_____?_____ –>
Platelet adhesion to blood vessel wall via glycoprotein IIb/IIIa receptors –>
Platelet activation –>
Platelet cytoskeleton (via actin and myosin) expands from a disc to a multi-pseudopodal sticky blob –>
Platelet aggregation –>
Serotonin –> ______ –>
ADP –> Recruits other platelets to aggregate and ____ –>
Thromboxane –> Platelet aggregation and PGF release
…and more cytokines, chemotactic and growth factors, etc., etc. than you can imagine (more are discovered on a monthly basis)

Binds von Willebrand Factor

Vasoconstriction

degranulate

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Wound –>
Exposes _____ –>
Binds von Willebrand Factor –>
Platelet adhesion to blood vessel wall via ________ –>
Platelet activation –>
Platelet cytoskeleton (via actin and myosin) expands from a disc to a multi-pseudopodal sticky blob –>
Platelet aggregation –>
Serotonin–> Vasoconstriction –>
___ –> Recruits other platelets to aggregate and degranulate –>
______ –> Platelet aggregation and PGF release
…and more cytokines, chemotactic and growth factors, etc., etc. than you can imagine (more are discovered on a monthly basis)

subendothelial collagen

glycoprotein IIb/IIIa receptors

ADP

Thromboxane

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Serotonin

Vasoconstriction

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ADP

Recruits other platelets to aggregate and degranulate

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Thromboxane

Platelet aggregation and PGF release

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PDGF: Platelet-Derived Growth Factor - does what??

STRONGLY mitogenic and chemotactic for leukocytes
By itself PDGF application doubles the rate of collagen deposition in a wound
(plus a bunch of other stuff that aggressively accelerates healing…)

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PDGF doubles what?

By itself PDGF application doubles the rate of collagen deposition in a wound

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TGF-β: Transforming Growth Factor-Beta

Also strongly mitogenic
Allows damaged (irradiated, corticosteroid-treated) tissues to revert to normalized collagen deposition

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Attracted neutrophils and macrophages release ?

a host of other healing factors

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Cells expressing the CD34

protein are concentrated where?

mononuclear layer of platelet concentrate-

These cells are stem cell “markers” and are important for other cells’ adhesion/chemotaxis

PRP

The components of whole blood remaining after the removal of (most of) the red cells”
The buffy coat (white cells and platelets) extending ??? into the top of the red cell column
PLUS all of the plasma

PPP

“Plasma layer without the buffy coat”

So…you get lots of fibrinogen & coagulation factors but no cells

Platelet concentrate?

Essentially the buffy coat +/- a small (variable) amount of plasma
Buffy coat = leukocytes + platelets

Leukocytes = neutrophils, eosinophils, basophils, macrophages, B- and T-lymphocytes

PG: Platelet Gel

Platelet Concentrate with enough fibrinogen (2-4mg/ml) to “set up” when combined with an activator
“Activator” = Thrombin (bovine or human), Calcium (usually CaCl₂) or Collagen
Platelets 2-6x over baseline

Platelet gel platelet concentration

2-6x over baseline

Platelet Gel activators?

“Activator” = Thrombin (bovine or human), Calcium (usually CaCl₂) or Collagen

Absolute numeric concentration of platelets needed in PG for it to work?

Absolute numeric concentration | -Typically > 1,000,000/μL

Increase in multiples above baseline concentration of platelets needed in PG for it to work?

- Typically 2-6 times above baseline | - Evidence suggests >6x actually delays healing

“Autologous platelet gel has supraphysiologic amounts of what??

“Autologous platelet gel has supraphysiologic amounts of platelet-derived growth factors in a sustained medium at the site of wound” As opposed to “single factors” As opposed to “autologous conditioned plasma”

Where PG used?

``` Cardiac surgery Vascular surgery Maxillofacial surgery Plastic and reconstructive surgery Burns Wound clinics Dental clinics Podiatrics Ophthalmics Veterinary Medicine ```

PG can help with all tissue but what kind?

Evidence supports its use in promoting healing in virtually all tissues except nervous tissue

PG Contraindications?

``` Severe hypovolemia Unstable angina/LM disease Heparin therapy Post-incisional harvest Thrombocytopenia (~ ```

Never, ever, EVER apply platelet concentrates to what??

coronary grafts (and don’t let surgeons do it, either!)

Harvest BMAC

Smart Prep 2 has the measuring looking glass plastic cup with the small end and big end separated by a little septum so PG goes in small side and RBC go in big side

100% platelet recovery means basically what?

just blood --- :/

1 μL =

one millionth of a liter

How many platelets in a “unit” of whole blood?

(Platelets/μL) X 1000 X (ml of whole blood)

How many platelets in a “unit” of PRP?

(Platelets/μL) X 1000 X (ml of PRP)

What is the percent yield of platelets in PRP?

(# platelets in PRP X 100)/(# platelets in whole blood)

Stem Cells come from where?

``` Bone Marrow (“Mesenchymal”) Derived Adipose Derived ```

Mesenchymal Cells- generally found where? | high capacity for what 2 things?

Generally found in the bone marrow but can be isolated from circulating blood, cord blood, fallopian tubes, and fetal tissue. High capacity for pluropotentiality High capacity for self renewal

Bone Marrow Stem Cells PRoblems?

Critters are “funny” about having a massive pointy needle rammed into their pelvis and having those contents removed with vigorous suction! People are less sensitive about having fat sucked out of “fat-rich” parts of their anatomy Stem cells are “few and far between” in the bone marrow

Adipose derived stem cells?

Also a source of multipotent (less pluropotent?) stem cells > 500 X more stem cells in 1 gram of fat as compared to 1 gram of aspirated bone marrow Have similar (+/-) ability to differentiate as does B.M.-derived. Can be extracted without anesthesia/ sedative/tranquilizer Avoids “fetal stem cell” discussion *Technology for utilizing adipose-derived stem cells is much simpler (and more commercially available) (Moving away from B.M. towards A.D.)

Adipose stem cell amount?

> 500 X more stem cells in 1 gram of fat as compared to 1 gram of aspirated bone marrow

Stem cells are synergistically attracted/stimulated by ?

activated platelets and the “factors” those platelets produce

Adipose derived stem cell extraction systems do All essentially do (at least) four (5) things?

All essentially do (at least) four things: 1) Remove the “lipids” 2) Remove the supernatant (saline, phenylephrine, lidocaine) 3) Concentrate the adipose stem cells (hopefully) 4) Maintain the Stromal Vascular Fraction (SVF) which creates a warm, fuzzy microenvironment for the stem cells and helps promote graft retention 5) +/or allow for the stem cell extract to be mixed at some ratio with platelet concentrate in an aerobic environment

Harvest Smartprep

AdiPrep system like a syringe that better separates the lipids from the oils, from the adipose tissue by centrifugal compared to just gravity

“Microscopic examination reveals that the lumen of a non-Cell Friendly cannula is a landscape of spikes and pits, and may contain caustic chemicals embedded in the stainless steel during tube processing”

SO use a cell friendly one so it can slide by all the cells