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REVIEW ARTICLE
Platelet-Rich Fibrin and Soft Tissue Wound Healing:
A Systematic Review
Richard J. Miron, DDS, MSc, PhD, dr. med. dent.,
1
Masako Fujioka-Kobayashi, DDS, PhD,
1–3
Mark Bishara, DDS,
4
Yufeng Zhang, DDS, MD, PhD,
5
Maria Hernandez, DDS, MS,
1
and Joseph Choukroun, MD
6
The growing multidisciplinary field of tissue engineering aims at predictably regenerating, enhancing, or
replacing damaged or missing tissues for a variety of conditions caused by trauma, disease, and old age. One
area of research that has gained tremendous awareness in recent years is that of platelet-rich fibrin (PRF), which
has been utilized across a wide variety of medical fields for the regeneration of soft tissues. This systematic
review gathered all the currently available in vitro,in vivo, and clinical literature utilizing PRF for soft tissue
regeneration, augmentation, and/or wound healing. In total, 164 publications met the original search criteria,
with a total of 48 publications meeting inclusion criteria (kappa score =94%). These studies were divided into 7
in vitro,11in vivo, and 31 clinical studies. In summary, 6 out of 7 (85.7%) and 11 out of 11 (100%) of the
in vitro and in vivo studies, respectively, demonstrated a statistically significant advantage for combining PRF
to their regenerative therapies. Out of the remaining 31 clinical studies, a total of 8 reported the effects of PRF
in a randomized clinical trial, with 5 additional studies (13 total) reporting appropriate controls. In those clinical
studies, 9 out of the 13 studies (69.2%) demonstrated a statistically relevant positive outcome for the primary
endpoints measured. In total, 18 studies (58% of clinical studies) reported positive wound-healing events asso-
ciated with the use of PRF, despite using controls. Furthermore, 27 of the 31 clinical studies (87%) supported the
use of PRF for soft tissue regeneration and wound healing for a variety of procedures in medicine and dentistry. In
conclusion, the results from the present systematic review highlight the positive effects of PRF on wound healing
after regenerative therapy for the management of various soft tissue defects found in medicine and dentistry.
Keywords: platelets, fibrin, PRP, PRF, angiogenesis, vascularization
Introduction
The multidisciplinary field of tissue engineering
aims at predictably repairing, regenerating, or restoring
damaged and supporting tissues, including cell, tissue, and
organs, due to an assortment of biological conditions, in-
cluding congenital abnormalities, injury, disease, and/or
aging.
1–4
During their regeneration, one key aspect involves
the ingrowth of a vascular source that is capable of sup-
porting cellular function and future tissue development by
maintaining a viable exchange of nutrients through blood
vessels.
5
Although the majority of tissue engineering scaf-
folds are avascular by nature, it remains essential that all
regenerative strategies focus on the development of a vas-
cular network to obtain successful clinical outcomes and
regeneration of either soft or hard tissues.
5
Wound healing, which is defined as the natural restorative
response to tissue injury, involves a cascade of complex,
orderly, and elaborate events involving many cell types
guided by the release of soluble mediators and signals that
are capable of influencing the homing of circulating cells to
damaged tissues.
6
Typically, wound-healing events are di-
vided into four overlapping phases, including hemostasis,
inflammation, proliferation, and remodeling.
7–9
Platelets
have been shown to be important cells regulating the he-
mostasis phase through vascular obliteration and facilitating
1
Department of Periodontology, Nova Southeastern University, Fort Lauderdale, Florida.
2
Cranio-Maxillofacial Surgery, Bern University Hospital, Inselspital, Bern, Switzerland.
3
Department of Oral Surgery, Clinical Dentistry, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima,
Japan.
4
West Bowmanville Family Dental, Ontario, Canada.
5
Department of Oral Implantology, University of Wuhan, Wuhan, China.
6
Pain Clinic, Nice, France.
TISSUE ENGINEERING: Part B
Volume 23, Number 1, 2016
ªMary Ann Liebert, Inc.
DOI: 10.1089/ten.teb.2016.0233
1
FOR REVIEW ONLY
NOT INTENDED FOR DISTRIBUTION
OR REPRODUCTION
fibrin clot formation.
6
Although debate has been ongoing as
to whether platelets should be regarded as cell fragments or
whole cells,
10
it is well known that they are responsible for
the activation and release of important biomolecules, in-
cluding platelet-specific proteins, growth factors including
platelet-derived growth factor (PDGF), coagulation factors,
adhesion molecules, cytokines/chemokines, and angiogenic
factors that are capable of stimulating the proliferation and
activation of cells involved in wound healing, including fi-
broblasts, neutrophils, macrophages, and mesenchymal stem
cells (MSCs).
11
For these reasons, the use of platelet con-
centrates has been utilized in modern medicine for more
than four decades due to their hypothesized impact on tissue
regeneration by facilitating angiogenesis and various addi-
tional phases during wound healing, including cell recruit-
ment, proliferation, remodeling, and differentiation. Later,
we describe how tissue-engineering constructs have utilized
various platelet concentrates to speed wound healing of ei-
ther soft or hard tissues.
Platelet concentrates: from platelet-rich plasma
to platelet-rich fibrin
Autologous platelet-rich plasma (PRP) was first devel-
oped in the early 1970s and was made popular in the
1980s.
12,13
The first generation of PRP was introduced by
mixing collected blood with thrombin and excess calcium,
resulting in activated platelets trapped within a fibrin net-
work. Since then, different platelet preparation protocols are
now available and traditionally isolated by a dual-speed
centrifugation process. The first spin separates red blood
cells from plasma and buffy coat. Thereafter, the platelet
plug is typically separated from the platelet-poor plasma in a
second spin cycle generating PRP, a platelet concentrate
with up to 6–8 times the concentration of growth factors
when compared with whole blood.
14
These platelets have
been shown to secrete high levels of bioactive substances
that slowly diffuse to the surrounding micro-environment
facilitating tissue regeneration.
15–19
Much advancement has
since been made in the medical field by various groups, who
demonstrated that PRP could further enhance surgical
wound healing of either soft or hard tissues.
15,20,21
Despite
its widespread use, one of the reported drawbacks was the
use of anti-coagulation factors delaying normal wound-
healing events.
Due to these reported limitations, further research was
focused on developing a second-generation platelet con-
centrate without utilizing anti-coagulation factors. As such,
a platelet concentrate lacking coagulation factors, later
termed platelet-rich fibrin (PRF), was developed due to its
anticipated properties in tissue regeneration and wound
healing.
22–25
PRF (also termed leukocyte-PRF), in addition,
contains more white blood cells (WBCs), necessary cells
that are important during the wound-healing process
(Fig. 2).
17,26–30
Furthermore, since WBCs, including neu-
trophils and macrophages, are one of the first cell types
found in wounded sites, their role also includes to phago-
cytize debris, microbes, and necrotic tissue, thereby pre-
venting infection. Macrophages are also key cells derived
from the myeloid lineage and are considered one of the key
cells implicated in growth factor secretion during wound
healing, including transforming growth factor beta (TGF-
beta), PDGF, and vascular endothelial growth factor (VEGF)
(Fig. 2). These cells, together with neutrophils and platelets,
are key players in wound healing and in combination with
their secreted growth factors/cytokines are capable of facili-
tating tissue regeneration, new blood vessel formation (an-
giogenesis), and prevention of infection.
22–25,28
To date,
numerous studies have investigated the regenerative potential
of PRF in various medical situations. The aim of this article
was to systematically characterize the potential for PRF to
influence soft tissue wound healing. A systematic search was
carried out, including all in vitro,in vivo, and clinical studies
performed on PRF to date dealing with soft tissue regen-
eration, wound healing, and/or angiogenesis after treatment
with PRF.
Methods
Development of a protocol
A protocol including all aspects of a systematic review
methodology was developed before commencing the re-
view. This included a definition of the focused question; a
defined search strategy; study inclusion criteria; determi-
nation of outcome measures; screening methods, data ex-
traction, and analysis; and data synthesis.
Defining the focused question
The following focused question was defined: ‘‘Does
platelet rich fibrin (PRF) affect/induce soft tissue regener-
ation and/or soft tissue wound healing?’’
Search strategy
Using the MEDLINE database, the literature was sear-
ched for articles published up to and including April 7th,
2016 (Figure 1). Combinations of several search terms were
FIG. 1. Flow chart of the screened
relevant publications.
2 MIRON ET AL.
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NOT INTENDED FOR DISTRIBUTION
OR REPRODUCTION
applied to identify appropriate studies (Table 1). Reference
lists of review articles and of the included articles in the
present review were screened.
Criteria for study selection and inclusion
Study selection considered only articles published in En-
glish, describing in vitro,in vivo, and human clinical studies
evaluating the effect of PRF on soft tissue wound healing. All
in vitro studies were included on fibroblasts, endothelial cells,
keratinocytes, and/or periodontal ligament fibroblasts. All
in vivo data specifically characterizing the effects of PRF on
soft tissue wound healing were included. All human studies
reporting the effects of PRF were also included. Human
studies were not limited to randomized clinical trials.
Outcome measure determination
The primary outcome of interest was to determine the
effect in percentage increases that PRF is capable of in-
ducing soft tissue regeneration and wound-healing events.
The outcome measures were separated into (1) in vitro
studies, (2) animal studies, and (3) clinical studies. Since
large variability in the outcomes measured was performed
by the various groups working across several fields of
medicine, a meta-analysis was not considered. Outcomes
were summarized in Tables 2–4 for the various in vitro,
in vivo, and clinical studies according to the specific effect
of PRF on soft tissue wound healing.
Screening method
Titles and abstracts of the selected studies were inde-
pendently screened by two reviewers (R.J.M. and M.F.-K.)
on April 7th, 2016. The screening was based on the ques-
tion: ‘‘What effect does platelet rich fibrin (PRF) have on
soft tissue regeneration and/or wound healing?’’ Full text
articles were obtained if the response to the screening
question was ‘‘yes’’ or ‘‘uncertain’’. The level of agreement
between reviewers was determined by kappa scores ac-
cording to company software instructions (GraphPad Soft-
ware, Inc., La Jolla, CA, http://graphpad.com/quickcalcs/
kappa1.cfm). Disagreement regarding inclusion was re-
solved by discussion between authors. For necessary miss-
ing data, the authors of the studies were contacted. Articles
referring strictly to use in tendons, and orthopedic/bone uses
were excluded if soft tissue wound-healing events were not
investigated/discussed. Furthermore, review articles and
clinical cases with no measurable endpoint were excluded.
Data extraction and analysis
The following data were extracted: general characteris-
tics (authors, year of publication), PRF centrifugation
characteristics/protocols, evaluation characteristics (amount
of PRF utilized, volume, period, outcome measures),
methodological characteristics (study design, methodologi-
cal quality), and conclusions. Because of the heterogeneity
FIG. 2. Representative
diagram of the cell types,
extracellular matrix compo-
nents, and bioactive mole-
cules found in PRF. PRF,
platelet-rich fibrin. Color
images available online at
www.liebertpub.com/teb
Table 1. Search Terms Used to Identify
the Relevant Studies
Search terms
‘‘Platelet Rich Fibrin’’ OR ‘‘PRF’’ OR ‘‘Platelet-Rich
Fibrin’’ OR ‘‘Leukocyte Platelet Rich Fibrin’’ OR
‘‘Leukocyte Platelet-Rich Fibrin’’ OR ‘‘LPRF’’ OR
‘‘L-PRF’’ OR ‘‘Advanced Platelet Rich Fibrin’’ OR
‘‘Advanced PRF’’ OR ‘‘A-PRF’’ OR ‘‘APRF’’
AND
‘‘Soft Tissue Regeneration’’ OR ‘‘Soft Tissue Wound
Regeneration’’ OR ‘‘Soft Tissue Wound-Healing’’ OR
‘‘Wound Healing’’ OR ‘‘Wound-Healing’’ OR ‘‘Soft
Tissue Augmentation’’ OR ‘‘Angiogenesis’’
PLATELET-RICH FIBRIN AND SOFT TISSUE WOUND HEALING 3
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of the included studies (study design, in vitro vs. animal vs.
clinical studies, investigated parameters, materials used,
evaluation methods, outcome measures, observation peri-
ods), no mean differences could be calculated, and conse-
quently, no quantitative data synthesis and meta-analysis
could be performed. Instead, the data are reported in a
systematic fashion characterizing all available literature to
date. Therefore, data were extracted from the reviewed ar-
ticles and summarized in separate tables based on the var-
ious in vitro,in vivo, and clinical studies and outcome
measures employed.
Results
In vitro studies evaluating the effects
of PRF on cell behavior
The evaluation of PRF on the cells found during soft
tissue regeneration and/or wound healing has been investi-
gated in seven in vitro studies to date (Table 2). The effects
of PRF have been investigated on (1) cell behavior of fi-
broblasts involved in soft tissue wound healing, (2) endo-
thelial cells, and (3) growth factor release from various PRF
formulations.
Effects of PRF on fibroblast cell behavior in vitro.In
2008, Lundquist was one of the first to evaluate the effects
of PRF on human dermal fibroblasts.
31
It was found that the
proliferative effect of PRF on dermal fibroblasts was sig-
nificantly greater than fibrin sealant and recombinant PDGF-
BB. Furthermore, PRF induced rapid release of collagen 1
and sustained release and protection against proteolytic
degradation of endogenous fibrogenic factors that are im-
portant for wound healing.
31
In a second in vitro study
conducted by Lundquist et al. in 2013, PRF induced the
mitogenic and migratory effect on cultured human dermal
fibroblasts and they further showed that fibrocytes (a cell
type important for acute wound healing) could be grown
from within PRF patches, further favoring wound healing
and soft tissue regeneration.
32
Thereafter, Clipet et al. found
that PRF induced fibroblast and keratinocyte cell survival
and proliferation.
33
In 2015, Vahabi et al. also confirmed
that PRF induced gingival fibroblast proliferation at 24 h;
however, they found that gingival fibroblast proliferation
was significantly higher in the plasma rich in the growth
factors group at 48 and 72 h.
34
In summary, it may, there-
fore, be concluded that PRF is able to induce the prolifer-
ation of dermal fibroblasts, gingival fibroblasts, and
keratinocytes, as well as it participates in their production of
extracellular matrix collagen 1 synthesis.
Effects of PRF on endothelial cell behavior. In the only
in vitro report investigating the effects of PRF on angio-
genesis in vitro, Roy et al. investigated the effects of PRF on
endothelial cells. It was found that PRF induced endothelial
Table 2. In Vitro Studies Evaluating the Effects of Platelet-Rich Fibrin
on Soft Tissue Regeneration and/or Wound Healing
Author Year Cell type Centrifugation protocol Findings/conclusions
Lundquist et al. 2008 Human dermal
fibroblasts
400 gfor 10 min PRF induced higher fibroblast proliferation
when compared with fibrin sealant and
recombinant PDGF. Furthermore, PRF
protected against proteolytic degradation
of endogenous fibrogenic factors
important for wound healing.
Roy et al. 2011 Endothelial cells 1100 gfor 6 min
(with trisodium citrate)
followed by 4500 g
for 25 min (with CaCl
2
)
PRF induced endothelial cell mitogenesis via
extracellular signal-regulated protein
kinase activation pathway.
Clipet et al. 2012 Keratinocytes,
fibroblasts
400 gfor 12 min Soluble growth factors from PRF induced
cell viability and proliferation
differentiation.
Lundquist et al. 2013 Human dermal
fibroblasts
3000 gfor 8 min
followed by 2 min
at 3000 g
Fibrocytes (important cells for acute wound
healing) were grown from within PRF
patches, implicating their role in wound
healing and soft tissue regeneration.
Ghanaati et al. 2014 PRF clots 150 gfor 14 min Introduction of A-PRF: By decreasing the
rpm/g-force while increasing the
centrifugation time in A-PRF, an enhanced
presence of neutrophilic granulocytes and
macrophages, cells were implicated in
wound healing.
Vahabi et al. 2015 Gingival
fibroblasts
400 gfor 12 min PRGF induced significantly higher gingival
fibroblast proliferation at 48 and 72 h when
compared with PRF.
Bayer et al. 2016 Primary
keratinocytes
2000 gfor 10 min
followed by 2000 g
for 10 min
PRF contains some anti-inflammatory/
microbial effects in human keratinocytes
through the expression of an antimicrobial
peptide hBD-2.
PRF, platelet-rich fibrin; PDGF, platelet-derived growth factor; A-PRF, advanced-PRF; PRGF, plasma rich in growth factors.
4 MIRON ET AL.
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Table 3. In Vivo Studies Evaluating the Effects of Platelet-Rich Fibrin
on Soft Tissue Regeneration and/or Wound Healing
Author Year Model Defect type Healing period
Centrifugation
protocol Findings/conclusions
Roy et al. 2011 Porcine ischemic
excisional wound
model
8-mm disposable punch
biopsies
14 days 1100 gfor 6 min
(with trisodium
citrate) followed
by 4500 gfor
25 min (with
CaCl
2
)
PRF improved wound angiogenesis in chronic wounds
and collagen matrix deposition.
Tunali et al. 2013 Rabbit soft tissue
healing in the oral
cavity
Mucoperiosteal flaps 3, 5, 10,
15, 30 days
3500 rpm for 15 min PRF induced the formation of new connective tissue
in a rabbit model of wound healing within 30 days.
Liu et al. 2013 Rabbit fat grafting in
plastic and
reconstructive
surgery
Subcutaneous injections
into the ear’s auricula
4, 12, 24 weeks 3000 rpm for 10 min The efficacy of adipose tissue implantation can be
enhanced by using PRF as a therapeutic adjuvant.
Suzuki et al. 2013 Subcutaneous
injection in rats
Subcutaneous
implantation on the
dorsal tissues of rats
14 days 3000 rpm for 10 min Subcutaneous injection of growth factors extracted
from PRF incorporated into a gelatin gel was found
to be more effective in acceleration of wound
healing than the commonly used PRP.
Li et al. 2013 Subcutaneous
injections in nude
mice
Subcutaneous
implantation under
the cutis
7, 14 days 2100 rpm (400 g) for
12 min
PRF readily integrated with surrounding tissues and
was partially replaced with collagen fibers 2 weeks
after implantation.
Soyer et al. 2013 Rat penile erethral
repair
5 mm vertical incision
in the penile urethra
24 h 2400 rpm for 12 min Use of PRF after urethral repair increased early
TGF-b-R and VEGF expression in urethral tissues.
Horii et al. 2014 Oral mucositis
induced in
hamsters
Intraperitoneal injection
of 5-fluorouracil
followed by light
scratching of the
cheek pouch
5, 9, and 14 days 3000 rpm (400 g) for
10 min
The PRF group exhibited significant improvements in
the size and histological features of the ulcer and in
themyeloperoxidase activity.
Sun et al. 2014 Male rat myocardial
infarctions
Regional myocardial
ischemia by left
coronary artery
ligation
42 days 600 gfor 5 min The combination of PRF with adipose-derived MSCs
improved the preservation of LV function and
attenuated LV remodeling.
Chen et al. 2014 Maxillofacial soft
tissue defects in
irradiated
minipigs
Right parotid gland
irradiation (20 Gy)
6 months 3000 rpm (400 g) for
10 min
Both adipose-derived stem cells and PRF facilitated
the repair of defects in maxillofacial soft tissue in
irradiated minipigs, and their combined use was the
most effective.
Reksodiputro
et al.
2014 Porcine facial plastic
and reconstructive
surgery
Full-thickness (FTSG)
and split-thickness
(STSG) skin grafts
14, 30 days 1500 gfor 15 min,
1800 gfor 60 min
PRF in FTSG and STSG increased type 1 collagen
formation. PRF, in addition to STSG, gave the best
skin graft take.
Chen et al. 2015 Ventricular
remodeling in rats
Acute myocardial
infarction induction
through left coronary
artery ligation
6 weeks 400 gfor 10 min Adipose-derived mesenchymal stem cells embedded
in PRF scaffolds promoted angiogenesis, preserved
heart function, and improved left ventricular
remodeling.
TGF-b, transforming growth factor beta; VEGF, vascular endothelial growth factor; MSC, mesenchymal stem cell; LV, left ventricular; FTSG, full-thickness skin graft; STSG, split-thickness skin graft.
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Table 4. Clinical Studies Evaluating the Effects of Platelet-Rich Fibrin on Soft Tissue Regeneration and/or Wound Healing
Author Year Model Defect type Healing period
Centrifugation
protocol Findings/conclusions
Steenvoorde et al. 2008 12 patients, hard-
to-heal wounds
Arterial leg ulcers, diabetic
foot ulcers, and
postoperative wound
infections (no controls)
Varied
considerably
3000 rpm
(400 g) for
10 min
PRF achieved full healing or a significant
reduction in wound diameter, with no
adverse effects.
Danielsen et al. 2008 20 patients,
chronic leg ulcer
Randomized observation of
epithelialization of donor
sites and meshed split-
thickness skin autografts
in chronic ulcers versus
skin autografts with/
without PRF
5, 8 days 3000 rpm
(400 g) for
10 min
Epithelial coverage of donor wounds
did not differ significantly between
platelet-rich fibrin and control on
day 5 (43.5% vs. 34.4%, p50.65) or
day 8 (76.6% vs. 94.8%, p50.17).
Anilkumar et al. 2009 One patient, root
coverage
7 mm of clinical attachment
loss on labial surface of
anterior teeth (no controls)
1 month 2700 rpm
for 12 min
Complete coverage was achieved 6
months after the procedure, with
excellent tissue contour and color.
O’Connell et al. 2008 12 patients, chronic
lower-extremity
ulcers
17 VLU (no controls) Weekly visits
for 12 weeks
3000 gfor
10 min
Complete closure was achieved in 66.7%
in the PRF group demonstrating VLU
versus 44% in the nontreated VLU
group.
Danielsen et al. 2010 51 patients,
laparoscopic
cholecystectomy
Randomized, PRF versus
albumin
10 days 3000 rpm
(400 g)
for 10 min
PRF did not improve wound strength
significantly compared with albumin
but suppressed subcutaneous
collagen synthesis and deposition
during early repair of surgical
wounds in humans.
Sclafani 2011 50 patients, plastic
surgery
PRF used for treatment of
deep nasolabial folds,
volume-depleted midface
regions, superficial rhytids,
and acne scars (no controls)
9.9 months
(range, 3–30
months).
1100 rpm for
6 min
Full patient biocompatibility. No patients
reported any swelling lasting more than
5 days. Most patients were satisfied
with treatment.
Sammartino et al. 2011 50 patients,
extractions (or
avulsions) for the
prevention of
hemorrhagic
complications
168 defects, extractions with
patients on anti-coagulant
therapies (no controls)
9 h 400 g18 min The proposed protocol with PRF is a
reliable therapeutic option to avoid
significant bleeding after dental
extractions without the suspension of
anticoagulant therapy in heart surgery
patients.
Sclafani et al. 2011 Four patients,
induction of
dermal
collagenesis,
angiogenesis, and
adipogenesis
PRF injected into the deep
dermis and immediate
subdermis of the upper
arms followed by 5 mm
full-thickness biopsy
collection (no controls)
10 weeks 1100 rpm
for 6 min
Injection of PRF into the deep dermis and
subdermis of the skin stimulates a
number of positive cellular changes,
including increases in collagen
production and angiogenesis.
(continued)
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Table 4. (Continued)
Author Year Model Defect type Healing period
Centrifugation
protocol Findings/conclusions
Jorgensen et al. 2011 15 patients,
recalcitrant
chronic wounds
16 lower-extremity chronic
wounds of varying etiology
(no controls)
6 weeks 3000 rpm for
12 min
Authors conclude that PRF is easy to
prepare and apply in the clinics, is safe,
and may be a clinically effective
treatment for recalcitrant chronic
wounds.
Gorlero et al. 2012 10 patients, vaginal
prolapse repair
Surgery for prolapse with
recurrence (stage II or
higher) (no controls)
1, 6, 12, 18, 24
months
3000 rpm for
12 min
The use of PRF for site-specific prolapse
repair is associated with a good
functional outcome because of the
healing and mechanical properties of
PRF.
Jankovic et al. 2012 15 patients, Miller
Class I or II
gingival
recessions
PRF or CTG 6 months 3000 rpm (400
g) for
10 min
No difference could be found between
PRF and CTG groups in gingival
recession therapy, except for a
greater gain in keratinized tissue
width obtained in the CTG group
and enhanced wound healing
associated with the PRF group.
Soyer et al. 2013 One patient,
urethracutaneous
fistula repair
Use of PRF in a 3-year-old
boy after hypospadias
repair (no controls)
1, 3 months 400 gfor
10 min
After treatment with PRF, no urethral
fistula was detected. Therapy with PRF
improved clinical outcomes in this case
report.
Chignon-
Sicard et al.
2012 68 patients, wound
healing
Postoperative hand wounds
(PRF vs. reference care
with petroleum jelly
mesh)
1, 2, 7, 14, 21,
28, 60 days
2700 rpm (400
g) for
12 min
PRF application on fresh postoperative
hand wounds showed a median
improvement of 5 days faster wound
healing in comparison to control.
Jain et al. 2012 One patient, palatal
wound healing
48 year-old man, palatal
wound (no control)
7, 14, 21,
28 days
3000 rpm for
10 min
Patient showed delayed wound healing
after subepithelial connective tissue
graft harvestation, which was re-treated
successfully with PRF.
Braccini et al. 2013 232 patients during
lipostructure
Fat tissue extracted from
inner side of knees (no
control)
2, 4, 6, 8
months
3400 rpm for
10 min
By offering a matricial support to
angiogenesis and by stimulating the
proliferation of pre-adipocytes, the PRF
demonstrated a beneficial role in the
cicatrization and the consolidation of
an adipocyte graft.
Hoaglin and Lines 2013 100 patients, third
molar extractions
200 defects, PRF placed in
half, reevaluated for
localized osteitis
(control =no therapy)
7–10 days 2700 rpm for
10–12 min
1% of cases with PRF were infected
versus 9.5% in control untreated sites.
PRF may be utilized to significantly
reduce osteomyelitis after third molar
extractions.
Desai et al. 2013 One patient, facial
soft tissue defect
30 year-old motorcycle
accident
2, 6 weeks 3000 rpm for
10 min
Innovative technique of enhancement of
skin wound healing by local application
of PRF
(continued)
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Table 4. (Continued)
Author Year Model Defect type Healing period
Centrifugation
protocol Findings/conclusions
Suttapreyasri
and Leepong
2013 20 patients, defect
wound fill
Extraction sockets, split
mouth, PRF versus blood
clot
1, 2, 4, 6, 8
weeks
3000 rpm for
10 min
PRF neither influenced alveolar ridge
preservation nor enhanced bone
formation in the extraction socket.
The use of PRF revealed some
effectiveness by accelerating
soft-tissue healing during the first
4 weeks.
Guinot et al. 2014 33 patients,
urethroplasty
coverage in distal
hypospadias
Urethroplasties performed
using Duplay’s technique
(no controls)
8 months
(range, 6–18
months)
3000 rpm for
10 min
PRF seemed to be a safe and efficient
covering technique, was reported as an
additional approach to coverage for
hypospadias surgery, and may help in
reducing the incidence of postoperative
complications when coverage healthy
tissue is not available.
Zumstein et al. 2014 20 consecutive
patients, repair
of chronic
rotator cuff
tears
Arthroscopic treatment
6PRF
6, 12 weeks 3000 rpm
(400 g) for
10 min
Arthroscopic rotator cuff repair with
the application of L-PRF is
technically feasible and yields higher
early vascularization.
Kulkarni et al. 2014 18 patients, healing
of free gingival
graft donor sites
Palatal wound healing with
PRF (control without PRF)
7, 14, 21 days 3000 rpm for
10 min
PRF as a dressing is an effective method
of enhancing the healing of the palatal
donor site and of, consequently,
reducing postoperative morbidity.
Habesoglu et al. 2014 32 patients with
acute traumatic
ear drum
perforations
PRF versus nothing was
used for the repair of ear
drum perforation
1 month 2700 rpm for
12 min
Here, we found that PRF is a
biomaterial that quickens the healing
of ear drum and that is autogenous
and simply prepared. In the study
group, the rate of ear drum closure
was 64.3% and in the control group it
was 22.2% (p<0.05).
Londahl et al. 2015 39 patients, hard-to-
heal DFU
PRF was applied weekly to
DFU for up to 20 weeks
(no control)
Every week up
to 20 weeks
3000 gfor
10 min
PRF was well tolerated, easy to use and
had potential in the armamentarium of
the DFU treatment.
Pathak et al. 2015 26 patients, oral
mucosal lesions
after excisions
PRF over healing areas of
potentially malignant
lesions
7, 15, 30, and
60 days
3000 rpm for
10 min
The results of the present study suggest
that the PRF membrane is a successful
coverage agent that aids in the healing
of superficial oral mucosal wounds.
Ajwani et al. 2015 20 patients, split
mouth, two- and
three-wall
intrabony defects
OFD –PRF (control OFD
alone)
9 months 3000 rpm
(400 g) for
10 min
Adjunctive use of PRF with OFD
significantly improves defect fill when
compared with OFD alone.
(continued)
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Table 4. (Continued)
Author Year Model Defect type Healing period
Centrifugation
protocol Findings/conclusions
Yelamali
and Saikrishna
2015 20 patients, split
mouth, third
molar extractions
Soft tissue healing after
extraction, PRF versus PRP
1 week 3000 rpm for
10 min
PRF is significantly better in promoting
soft tissue healing when compared with
PRP.
di Lauro et al. 2015 Two patients,
exeresis of
hyperplastic
gingival lesions
Exeresis of lesions and
application of PRF (no
control)
1, 3, 7, 14,
30 days
2700 rpm for
12 min
PRF led to rapid and good healing of soft
tissues, and the authors suggest that the
use of PRF can be applied to cover
wounds after exeresis of oral
neoformations such as hyperplastic
gingival lesions.
Eren et al. 2015 14 patients, gingival
recession
Treatment with connective
tissue graft or PRF
(control =CTG)
1, 6 months 3000 rpm for
10 min
PRF resulted in earlier vessel formation
and tissue maturation compared with
CTG.
Femminella et al. 2016 40 patients with
one site of Miller
Class I or II
gingival
recession
Palatal wounds covered
with PRF versus palatal
sponge
1, 2, 3, 4 weeks 3000 rpm for
10 min
The PRF-enriched palatal bandage
significantly accelerates palatal
wound healing and reduces patient
morbidity.
Bayer et al. 2016 Bilateral gluteal
wounds
Paraffin embedding and
mRNA extraction (no
controls)
10 days 2000 gfor
10 min
followed by
2000 gfor
10 min
PRF induced hBD-2 (implicated in wound
healing) expression when applied to
experimentally generated skin wounds.
Munoz et al. 2016 11 patients,
periodontally
accelerated
osteogenic
orthodontics
A Wilcko’s modified PAOO
technique with L-PRF (no
controls)
1, 2, 4, 8,
10 days
3000 rpm for
10 min
Combination with traditional bone grafts;
PRF potentially accelerates wound
healing and reduces postsurgical pain,
inflammation, and infection.
‘‘Bold’’ signifies a total of eight studies that have reported the effects of PRF in a randomized clinical trial.
VLU, venous leg ulcers; CTG, connective tissue graft; DFU, diabetic foot ulcers; OFD, open-flap debridement; PAOO, periodontally accelerated osteogenic orthodontics; PRP, platelet-rich plasma.
9
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cell mitogenesis via the extracellular signal-regulated pro-
tein kinase activation pathway.
35
A slow and steady release
of growth factors from their PRF matrix was observed to be
releasing VEGF, a known growth factor responsible for
endothelial mitogenic response. These authors provide some
evidence of probable mechanisms of action of PRF matrix in
healing of chronic wound ulcers.
35
Effect of PRF on growth factor release. It has long been
observed that PRF releases an array of growth factors to the
surrounding micro-environment that contributes to soft tis-
sue wound healing.
24
Interestingly, in 2014, a new protocol
for PRF was introduced (termed Advanced-PRF or A-PRF)
whereby centrifugal forces were decreased and total spin
times were increased.
36
By decreasing the rpm while in-
creasing the centrifugation time in the A-PRF group, an
enhanced presence of neutrophilic granulocytes in the distal
part of the clot was found to be contributing to monocyte
differentiation to macrophages,
36
a cell responsible for in-
ducing new bone formation.
37,38
Therefore, this article
concludes with the importance of centrifugation g-force on
growth factor to the surrounding environment, which may
be optimized by centrifugation time and speeds.
In a study investigating growth factors released
from various PRF components, Kobayashi et al. quantified
by enzyme-linked immunosorbent assay growth factors
including PDGF-AA, PDGF-AB, PDGF-BB, TGF-beta,
VEGF, and insulin-like growth factor (IGF).
39
Each of these
growth factors has a specific role in tissue regeneration.
Platelet-derived growth factor. PDGFs are essential reg-
ulators for the migration, proliferation, and survival of mes-
enchymal cell lineages.
40
According to the distribution of
mesenchymal-cell specific receptors, they are able to induce
stimulation in mesenchymal cells.
40
For this reason, PDGFs
play a critical role in physiologic wound healing and have
been FDA approved for the regeneration of various defects in
medicine and dentistry.
41,42
Interestingly, PDGF is naturally
found in PRF clots and is produced over time by leukocytes;
therefore, it is considered one of the important released bio-
active growth factors secreted over time from PRF.
Transforming growth factor-beta. TGF-beta is a vast su-
perfamily of more than 30 members known as fibrosis
agents, with TGF-beta1 being the most well described in the
literature.
43,44
It is a known stimulator of proliferation of
various mesenchymal cell types, including osteoblasts,
45
constituting the most powerful fibrosis agent among all
cytokines.
44
It plays a prominent role in matrix molecule
synthesis such as collagen1 and fibronectin, whether by
osteoblasts or fibroblasts. Although its regulatory mecha-
nisms are particularly complex, TGF-beta1 plays an active
role in wound healing.
43,44
Vascular endothelial growth factor. VEGF is the most
potent growth factor responsible for angiogenesis of tis-
sues.
46
It has potent effects on tissue remodeling and the
incorporation of VEGF alone into various bone biomaterials
has demonstrated increases in new bone formation, thereby
pointing to the fast and potent effects of VEGF.
46,47
Insulin-like growth factor. IGF is a positive regulator of
proliferation and differentiation for most mesenchymal cell
types, which also act as cell-protective agents.
48
Although
these cytokines are cell proliferative mediators, they also
constitute the major axis of programmed cell death (apo-
ptosis) regulation, by inducing survival signals protecting
cells from many apoptotic stimuli.
48
Although many known growth factors are present within
PRF clots, it remains interesting to note that further mole-
cules are being investigated from PRF for their various roles
in tissue wound healing. For example, Bayer et al. investi-
gated for the first time the properties that are contained
within PRF that may contribute to its anti-inflammatory/
anti-microbial activities.
49
It was discovered that in human
keratinocytes, PRF induced the expression of hBD-2, an
anti-microbial agent necessary in the treatment of chronic
and infected wounds.
49
Further in vitro research is necessary
to characterize the potential anti-inflammatory/anti-microbial
activity in PRF.
Conclusions from in vitro research. In total, six of seven
(85.6%) reported studies demonstrate a positive effect of
PRF on soft tissue cell behavior in vitro. In all studies,
appropriate controls were utilized. It was found that PRF
was able to increase cell proliferation in a number of cells
implicated in soft tissue repair, induced the mitogenic
activity of endothelial cells important for angiogenesis,
released an array of growth factors to the surrounding
micro-environment, and possessed properties leading to its
anti-inflammatory and anti-microbial activity.
In vivo studies evaluating the effects of PRF
on soft tissue regeneration and/or wound healing
In total, 11 studies have evaluated the effects of PRF on
soft tissue wound healing and regeneration (Table 3). These
studies may be classified under the following four sub-
headings, including the effects of PRF on (1) wound healing
and angiogenesis, (2) plastic and reconstructive purposes in
the ear’s auricular, (3) urethral repair, and (4) myocardial
ischemia and ventricular remodeling.
Effects of PRF on wound healing and angiogenesis
in vivo.The effects of PRF have most notably been in-
vestigated on soft tissue wound healing and angiogenesis in
various animal models. In the first study, Roy et al. evalu-
ated PRF after 14 days in a porcine ischemic excision
wound model, where 8-mm skin biopsies were created and
filled with PRF versus control.
35
It was found that PRF
significantly improved angiogenesis in chronic wounds and
collagen matrix deposition (Fig. 3).
35
Suzuki et al. further
showed that PRF induced faster wound healing and angio-
genesis in the dorsal tissues of rats after 14 days.
50
In an-
other subcutaneous implantation model performed in mice,
PRF readily integrated with surrounding tissues and was
partially replaced with collagen fibers 2 weeks after im-
plantation.
51
Furthermore, Horii et al. concluded that PRF
significantly spread soft tissue healing of oral mucosititis in
rats after a 14 day healing period (Fig. 4).
52
Tunali et al.
found that PRF centrifuged in titanium vials improved soft
tissue wound healing in a mucoperiosteal flap defect
model in rabbits 30 days after implantation.
53
In a model
designed to regenerate the parotid gland after their irradia-
tion in minipigs, both adipose-derived stem cells and PRF
10 MIRON ET AL.
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significantly sped the repair of defects in maxillofacial soft
tissue in irradiated minipigs, and their combined use was
more effective after a 6-month healing period.
54
In 2014, it
was found that PRF increased type 1 collagen formation in
full- and split-thickness flaps and improved skin graft take in
a skin graft model performed in porcine animals.
55
The
totality of these studies show convincingly that PRF is able
to increase soft tissue wound healing in various animal
models, and reports document that this is primarily due to
the increase in angiogenesis to defect sites.
Effect of PRF for plastic and reconstructive purposes in
the ear’s auricular in vivo.In one study, the effect of PRF
has been combined with adipose tissue for fat pad grafting in
the ear’s auricular. Liu et al. found that after a 24 week
healing period, fat grafting with PRF into the ear’s auricula
could be enhanced with PRF as a therapeutic adjuvant to
these procedures.
56
Histological examinations showed that
the implanted adipose granules were well engrafted in the
group containing PRF, demonstrating a higher microvessel
density 4 weeks postimplantation ( p<0.01).
56
At 24 weeks
postimplantation, the resorption rates of implanted tissue in
each group were also significantly different, with PRF
demonstrating the least resorption after the study endpoints
(p<0.01).
56
The results from this study conclude that PRF
can effectively be combined with adipose tissue as a ther-
apeutic adjuvant offering a clinically translatable strategy
for soft tissue augmentation and reconstruction of the ear.
Effects of PRF on urethral repair in vivo.The effect of
PRF was investigated on urethral repair in one animal study.
Soyer et al. found in a 5 mm penile erethral defect model in
18 Wistar albino rats that treatment with PRF significantly
increased TGF-beta and VEGF growth factor release after
24 h.
57
These authors conclude that the use of PRF after
urethral repair increases TGF-b-receptor and VEGF ex-
pression in urethral tissue and may be considered an alter-
native measure to improve the success of urethral repair.
Effects of PRF on the repair of myocardial ischemia and
ventricular remodeling in vivo.The effect of PRF on the
FIG. 3. Treatment of porcine ischemic wound with
PRFM. Representative digital images of excisional wounds
treated or not with PRFM on days 0 and 4 postwounding.
Adapted with permission from Roy et al.
35
PRFM, PRF
matrix. Color images available online at www.liebertpub
.com/teb
FIG. 4. Macroscopic as-
pects of the cheek pouches of
hamsters injected with 5-
fluorouracil. The control
group (A–C), the fibrin group
(D–F), and the PRF group
(G–I) are shown. Notice the
significantly faster wound
healing associated with the
PRF group.
52
Color images
available online at www
.liebertpub.com/teb
PLATELET-RICH FIBRIN AND SOFT TISSUE WOUND HEALING 11
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repair of heart-related injuries has been investigated in two
studies. Sun et al. first demonstrated that the combination of
PRF with adipose derived MSCs improved the preservation
of left ventricular (LV) function and attenuated LV re-
modeling in a rat model that induced regional myocardial
ischemia by left coronary artery ligation.
58
Furthermore, in
2015, adipose-derived MSCs were embedded in PRF scaf-
folds to investigate its effect on angiogenesis in heart tis-
sues.
59
It was found that the combination of PRF with
adipose cells promoted angiogenesis, preserved heart func-
tion, and reduced LV remodeling in rat acute myocardial
infarction when compared with controls (Fig. 5).
59
It may,
therefore, be concluded that in both studies, the additional
use of PRF led to improved heart function and angiogenesis;
however, both research groups point to the fact that further
study is necessary before these findings may be translated to
clinical use.
Conclusions from in vivo research. In total, 11 studies
found that PRF significantly improved soft tissue regener-
ation, wound healing, and/or angiogenesis in various animal
models investigated. In all studies, appropriate controls were
utilized. It was found that PRF was able to promote soft
tissue wound healing in various wound-healing models by
promoting local angiogenesis to defect sites, could be
combined with adipose tissue/cells to further improve re-
generation, could successfully be utilized for urethral repair,
and led to improvements in myocardial ischemia and ven-
tricular remodeling.
Clinical studies evaluating the effects of PRF
on soft tissue regeneration and/or wound healing
In total, 31 studies investigated the effects of PRF on soft
tissue wound healing/regeneration in various clinical sce-
narios. Table 4 presents a summary of each of the outcomes
found in each of the clinical studies, with italicization de-
noting randomized clinical studies with appropriate controls.
The use of PRF has been utilized for 20 different clinical
procedures; 7 of which come from the oral and maxillofacial
FIG. 5. Illustration of IVIS study and anatomical and pathological findings on day 42 after AMI induction (n=8). (A)
Serial assessments of living imaging by IVIS after AMI. (B) The anatomical findings showed the cross-sectional area of the
heart at the papillary muscle (blue arrowheads) among the four groups. The LV chamber size was the highest in the AMI
group, lowest in the sham-control group, and notably higher in the AMI +PRF group than in AMI +PRF +ADMSC;
conversely, the infarct size showed an opposite pattern of LV chamber size. The black arrowheads indicated PRF scaffold
tissue in the AMI +PRF group and ADMSC-embedded PRF scaffold (AMI +PRF +ADMSC) (i.e., engineered ADMSC
grafts) group, whereas the green arrowheads show the wall thickness in the infarct area. Scale bars =5 mm. (C) *versus
other groups with different symbols (*, {,{,x), p<0.001. Statistical analysis using one-way analysis of variance, followed
by Bonferroni multiple-comparison post hoc test. Symbols (*, {,{,x) indicate significance (at 0.05 level). Adapted with
permission from Chen et al.
59
IVIS, in vivo imaging system; AMI, acute myocardial infarction; LV, left ventricular;
ADMSC, adipose-derived mesenchymal stem cell. Color images available online at www.liebertpub.com/teb
12 MIRON ET AL.
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region (Table 4). In the dental field, the most commonly
utilized use of PRF was for the treatment of extraction
sockets,
60–63
gingival recessions,
64–66
and palatal wound
closure
67–69
with PRF being additionally utilized for the
repair of potentially malignant lesions,
70
regeneration of
periodontal defects,
71
hyperplastic gingival tissues,
72
and in
addition to periodontally accelerated osteogenic orthodon-
tics.
73
In other medical procedures, the use of PRF has been
mostly combined for the successful management of hard-to-
heal leg ulcers, including diabetic foot ulcers, venous leg
ulcers, and chronic leg ulcers.
74–78
Furthermore, PRF has
been investigated for the management of hand ulcers,
79
fa-
cial soft tissue defects,
80
laparoscopic cholecystectomy,
81
in
plastic surgery for the treatment of deep nasolabial folds,
volume-depleted midface regions, facial defects, superficial
rhytids and acne scars,
82
induction of dermal collagenesis,
83
vaginal prolapse repair,
84
urethracutaneous fistula re-
pair,
85,86
during lipostructure surgical procedures,
87
chronic
rotator cuff tears,
88
and acute traumatic ear drum perfora-
tions.
89
A total of eight studies have reported the effects of
PRF in a randomized clinical trial (Table 4, bolded). Five
nonrandomized studies reported appropriately selected
controls, whereas 18 studies (58% of the total listed clinical
studies) reported no controls in their investigation and in-
stead focused on the technical utilization/aspects of com-
bining PRF during their various medical procedures. In
total, 9 of the 13 studies utilizing appropriate controls re-
ported a significant positive influence combining PRF to
their surgical protocols during soft tissue wound healing
(Table 4). In total, 27 of the 31 studies (87%) reported
having beneficial effects for the utilization of PRF during
soft tissue regeneration and/or soft tissue wound healing and
angiogenesis in human applications. Noteworthy, 18 of 31
studies (58%) did not use appropriate controls in their
clinical studies.
Discussion and Future Perspectives
Platelet concentrates, including PRP and PRF, have been
used for regenerative procedures in various fields of medi-
cine, including dentistry, reconstructive surgery, plastic
surgery, and dermatology, to deliver supernatural concen-
trations of autologous growth factors directly to host tissues.
These growth factors have been shown to be chemotactic for
various cell types, including monocytes, fibroblasts, endo-
thelial cells, stem cells, and fibroblasts, creating tissue
micro-environments and directly influencing the prolifera-
tion and differentiation of progenitor cells.
90
Furthermore,
platelet concentrates are safe, reliable, and cost-effective
means to accelerate tissue healing and for improving the
efficiency of tissue repair after injury.
In the present study, we investigated specifically the re-
generative potential of soft tissue after use of PRF. To date,
no systematic review has characterized the regenerative
potential of PRF specifically for soft tissue wound-healing/
regeneration, despite the great number of in vitro,in vivo,
and clinical studies that have been reported on this topic to
date. Although a large number of research to date has fo-
cused on the effects of PRP on various wound-healing
events such as tendon regeneration,
91–95
this systematic re-
view article focused specifically on the regenerative poten-
tial of PRF for soft tissue management and excluded all
studies where PRF was utilized for bone, cartilage, or ten-
don regeneration. In total, 48 studies met our inclusion
criteria, with 31 studies being derived from human clinical
studies (Table 4).
Although the effects of PRF were shown to enhance soft
tissue regeneration in all but one in vitro and in vivo study
(18 studies total), the results from the clinical studies need to
be interpreted with caution. In total, 18 of the 31 clinical
studies (58%) report a beneficial effect of PRF based on the
investigators’ reported clinical experience; however, in
these studies, no controls were utilized and the authors in-
stead focused primary on their case reports/case series
(Table 4). In contrast, all in vitro and in vivo studies utilized
appropriate controls. It may, therefore, be concluded that
this first wave of research provides the clinical evidence that
PRF seems to promote soft tissue wound healing; however,
it is clear that future human studies are needed to system-
atically compare the effects of PRF in a randomized, con-
trolled fashion across a wide range of medical fields.
Similarly, it was recently reported in a systematic review
that the effects of platelet concentrates showed similar
findings on bone healing/formation of extraction sockets and
intrabony defects (Fig. 6).
96,97
Although the results of that
meta-analysis are suggestive that platelet concentrates in-
crease new bone formation in postextraction sockets, the
authors report that due to the limited amount and quality of
the available evidence, these results need to be cautiously
interpreted.
96
It was reported that a standardization of the
experimental design was necessary for a better understand-
ing of the true effects of the use of platelet concentrates for
enhancing postextraction socket healing.
96
Within the limits
of our review article, we conclude similar findings that the
effects of PRF enhance soft tissue regeneration; however,
future studies on soft tissue regeneration after use of PRF
need to be designed with appropriate controls and these
findings need also to be interpreted with caution until further
randomized clinical trials are gathered.
One of the reported advantages of PRF was the ability for
the fibrin network containing leukocytes to resist and fight
infection. Chronic nonhealing wounds are a significant
medical challenge and the pathogenesis of nonhealing
wounds, therefore, requires new treatment options to im-
prove clinical outcomes. One of the main factors to date
hypothesized to further speed the wound-healing properties
of PRF in comparison to PRP is the fact that it contains
higher levels of WBCs that favor the continuous release of
growth factors. Recently, we demonstrated that both PRF
and the new formulation of PRF termed A-PRF were able to
release significantly higher levels of growth factors when
compared with PRP over a 10-day period.
39
Furthermore,
macrophages have been shown to be key players during
tissue regeneration, wound healing, and prevention of in-
fection.
28,37,38
Furthermore, they contain antimicrobial ef-
fects that are capable of reducing bacterial contamination
after surgeries.
28
This finding was best exemplified in the
healing of third molar extraction sockets.
61
It was reported
that infection (osteomyelitis) is commonly reported in 9.5%
of wisdom tooth removal and when a PRF plug was inserted
after extraction, this was significantly reduced to 1% of
cases.
61
Despite these reported findings, very little is yet
known what the antibacterial properties of PRF are, as very
little/few studies have investigated this phenomenon.
98
PLATELET-RICH FIBRIN AND SOFT TISSUE WOUND HEALING 13
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From a tissue-engineering standpoint, it remains inter-
esting to note that no research to date has focused on the
strength, stiffness, or toughness of PRF despite its clinical
use for more than 15 years. Therefore, it remains of interest
to better characterize its biomaterial properties and future
research should focus on what factors might further improve
its characteristics for various biomedical applications. For
instance, it may be that for cartilage regeneration, versus
ligament repair versus periodontal soft tissue management
that variations of PRF may be further modified depending
on the tensile demands and requirements of the defect. As
currently only one centrifugation protocol of PRF is utilized
for clinical use, it remains of interest to further study how
modifications in centrifugation speeds and time might affect
the biomechanical properties of PRF for various medical
applications.
Furthermore, to date, very little is known regarding the
effects of the fibrin architecture and leukocyte content from
these products, as both these components are too often ne-
glected as contributing factors in the tissue regenerative
potential of PRF. The presence of leukocytes has a great
impact on the biology of wound healing,
17,30
not only due to
their additional release of growth factors and their impli-
cations in antibacterial immune defense but also because
they are key regulators controlling the wound-healing en-
vironment through local factor regulation. Future basic re-
search should focus specifically on the contribution of these
cells in specific cell knock-down/knock-in systems to de-
termine the functional roles of each cell in the wound-
healing process when PRF is utilized. For instance, it has
been reported that addition of activated macrophage to
wounds in aging mice and humans accelerated healing
time.
28
Thus, in theory, the concept of developing newer
modified protocols of PRF to further increase the number of
WBCs would, in principle, increase wound repair. Never-
theless, a better understanding of the individual roles of the
various cells found in PRF could prove to be an important
finding for the development of these technologies, leading to
modern changes to their protocols and further increasing
their regenerative potential.
Conclusion
In summary, two main findings can be drawn from the
present systematic review: (1) The currently available liter-
ature supports soft tissue regeneration after soft tissue re-
generative procedures utilizing PRF; and (2) there is a lack of
appropriate controls to the majority of studies drawing con-
clusive evidence that PRF is able to further, as most of the
clinical studies to date thus far highlight the use of PRF in
case series experiments or retrospective analysis without
comparative results to appropriate controls. Therefore, it is
imperative that the next wave of research utilizing PRF as an
adjunct to soft tissue regenerative therapies designs appro-
priate studies with necessary controls to further evaluate the
regenerative potential of PRF for soft tissue wound healing.
Disclosure Statement
No competing financial interest exist.
References
1. Coury, A.J. Expediting the transition from replacement
medicine to tissue engineering. Regen Biomater 3, 111, 2016.
2. Dai, R., et al. Adipose-derived stem cells for tissue engi-
neering and regenerative medicine applications. Stem Cells
Int 2016, 6737345, 2016.
3. Rouwkema, J., and Khademhosseini, A. Vascularization
and angiogenesis in tissue engineering: beyond creating
static networks. Trends Biotechnol 34, 733, 2016.
4. Zhu, W., et al. 3D printing of functional biomaterials for
tissue engineering. Curr Opin Biotechnol 40, 103, 2016.
5. Upputuri, P.K., et al. Recent developments in vascular
imaging techniques in tissue engineering and regenerative
medicine. Biomed Res Int 2015, 783983, 2015.
6. Guo, S., and Dipietro L.A. Factors affecting wound healing.
J Dent Res 89, 219, 2010.
FIG. 6. Clinical diagram of intrabony defect regeneration with PRF. Notice the initial lesions and soft tissue recessions
that have successfully been regenerated after application with PRF. Adapted with permission from Anuroopa et al.
97
Color
images available online at www.liebertpub.com/teb
14 MIRON ET AL.
FOR REVIEW ONLY
NOT INTENDED FOR DISTRIBUTION
OR REPRODUCTION
7. Gosain, A., and DiPietro, L.A. Aging and wound healing.
World J Surg 28, 321, 2004.
8. Eming, S.A., et al. Regulation of angiogenesis: wound
healing as a model. Prog Histochem Cytochem 42, 115, 2007.
9. Eming, S.A., et al. [Chronic wounds. Novel approaches in
research and therapy]. Hautarzt 58, 939, 2007 (Article in
german).
10. Garraud, O., and Cognasse, F. Are platelets cells? And if
yes, are they immune cells? Front Immunol 6, 70, 2015.
11. Nurden, A.T. Platelets, inflammation and tissue regenera-
tion. Thromb Haemost 105 Suppl 1, S13, 2011.
12. Heyns Adu, P., et al. Zinc-induced platelet aggregation is
mediated by the fibrinogen receptor and is not accompanied
by release or by thromboxane synthesis. Blood 66, 213,
1985.
13. Marx, R.E., et al. Platelet-rich plasma: growth factor en-
hancement for bone grafts. Oral Surg Oral Med Oral Pathol
Oral Radiol Endod 85, 638, 1998.
14. Peerbooms, J.C., et al. Use of platelet rich plasma to treat
plantar fasciitis: design of a multi centre randomized con-
trolled trial. BMC Musculoskelet Disord 11, 69, 2010.
15. Rozman, P., and Bolta, Z. Use of platelet growth factors in
treating wounds and soft-tissue injuries. Acta Dermatove-
nerol Alp Pannonica Adriat 16, 156, 2007.
16. Alsousou, J., et al. The biology of platelet-rich plasma and
its application in trauma and orthopaedic surgery: a review
of the literature. J Bone Joint Surg Br 91, 987, 2009.
17. Davis, V.L., et al. Platelet-rich preparations to improve
healing. Part I: workable options for every size practice. J
Oral Implantol 40, 500, 2014.
18. De Pascale, M.R., et al. Platelet derivatives in regener-
ative medicine: an update. Transfus Med Rev 29, 52,
2015.
19. Grambart, S.T. Sports medicine and platelet-rich plasma:
nonsurgical therapy. Clin Podiatr Med Surg 32, 99, 2015.
20. Whitman, D.H., Berry, R.L., and Green, D.M. Platelet gel:
an autologous alternative to fibrin glue with applications in
oral and maxillofacial surgery. J Oral Maxillofac Surg 55,
1294, 1997.
21. Borzini, P., et al. Platelet gel—the Italian way: a call for
procedure standardization and quality control. Transfus
Med 16, 303, 2006.
22. Choukroun, J., et al. Platelet-rich fibrin (PRF): a second-
generation platelet concentrate. Part IV: clinical effects on
tissue healing. Oral Surg Oral Med Oral Pathol Oral Radiol
Endod 101, e56, 2006.
23. Dohan, D.M., et al. Platelet-rich fibrin (PRF): a second-
generation platelet concentrate. Part I: technological con-
cepts and evolution. Oral Surg Oral Med Oral Pathol Oral
Radiol Endod 101, e37, 2006.
24. Dohan, D.M., et al. Platelet-rich fibrin (PRF): a second-
generation platelet concentrate. Part II: platelet-related bi-
ologic features. Oral Surg Oral Med Oral Pathol Oral
Radiol Endod 101, e45, 2006.
25. Dohan, D.M., et al. Platelet-rich fibrin (PRF): a second-
generation platelet concentrate. Part III: leucocyte activa-
tion: a new feature for platelet concentrates? Oral Surg Oral
Med Oral Pathol Oral Radiol Endod 101, e51, 2006.
26. Martin, P., and Leibovich, S.J. Inflammatory cells during
wound repair: the good, the bad and the ugly. Trends Cell
Biol 15, 599, 2005.
27. Tsirogianni, A.K., Moutsopoulos, N.M., and Moutsopoulos,
H.M. Wound healing: immunological aspects. Injury 37
Suppl 1, S5, 2006.
28. Adamson, R. Role of macrophages in normal wound
healing: an overview. J Wound Care 18, 349, 2009.
29. Davis, V.L., et al. Platelet-rich preparations to improve
healing. Part II: platelet activation and enrichment, leuko-
cyte inclusion, and other selection criteria. J Oral Implantol
40, 511, 2014.
30. Ghasemzadeh, M., and Hosseini, E. Intravascular leukocyte
migration through platelet thrombi: directing leukocytes to
sites of vascular injury. Thromb Haemost 113, 1224, 2015.
31. Lundquist, R., Dziegiel, M.H., and Agren, M.S. Bioactivity
and stability of endogenous fibrogenic factors in platelet-
rich fibrin. Wound Repair Regen 16, 356, 2008.
32. Lundquist, R., et al. Characteristics of an autologous leu-
kocyte and platelet-rich fibrin patch intended for the
treatment of recalcitrant wounds. Wound Repair Regen 21,
66, 2013.
33. Clipet, F., et al. In vitro effects of Choukroun’s platelet-rich
fibrin conditioned medium on 3 different cell lines impli-
cated in dental implantology. Implant Dent 21, 51, 2012.
34. Vahabi, S., et al. Effects of plasma rich in growth factors
and platelet-rich fibrin on proliferation and viability of
human gingival fibroblasts. J Dent (Tehran) 12, 504, 2015.
35. Roy, S., et al. Platelet-rich fibrin matrix improves wound
angiogenesis via inducing endothelial cell proliferation.
Wound Repair Regen 19, 753, 2011.
36. Ghanaati, S., et al. Advanced platelet-rich fibrin: a new
concept for cell-based tissue engineering by means of in-
flammatory cells. J Oral Implantol 40, 679, 2014.
37. Miron, R.J., and Bosshardt, D.D. OsteoMacs: key players
around bone biomaterials. Biomaterials 82, 1, 2016.
38. Sinder, B.P., Pettit, A.R., and McCauley, L.K. Macro-
phages: their emerging roles in bone. J Bone Miner Res 30,
2140, 2015.
39. Kobayashi, E., et al. Comparative release of growth factors
from PRP, PRF, and advanced-PRF. Clin Oral Investig
2016. [Epub ahead of print]; DOI: 10.1007/s00784-016-
1719-1.
40. Ng, F., et al. PDGF, TGF-b,and FGF signaling is important
for differentiation and growth of mesenchymal stem cells
(MSCs): transcriptional profiling can identify markers and
signaling pathways important in differentiation of MSCs
into adipogenic, chondrogenic, and osteogenic lineages.
Blood 112, 295, 2008.
41. Pierce, G., et al. Detection of platelet-derived growth factor
(PDGF)-AA in actively healing human wounds treated with
recombinant PDGF-BB and absence of PDGF in chronic
nonhealing wounds. J Clin Invest 96, 1336, 1995.
42. Howell, T.H., et al. A phase I/II clinical trial to evaluate a
combination of recombinant human platelet-derived growth
factor-BB and recombinant human insulin-like growth
factor-I in patients with periodontal disease. J Periodontol
68, 1186, 1997.
43. Border, W.A., and Noble, N.A. Transforming growth factor
beta in tissue fibrosis. N Engl J Med 331, 1286, 1994.
44. Bowen, T., Jenkins, R.H., and Fraser, D.J. MicroRNAs,
transforming growth factor beta-1, and tissue fibrosis. J
Pathol 229, 274, 2013.
45. Roberts, A.B., et al. Transforming growth factor bbiochem-
istry and roles in embryogenesis, tissue repair and remodel-
ing, and carcinogenesis. In Recent Progress in Hormone
Research: Proceedings of the 1987 Laurentian Hormone
Conference. San Diego, CA: Academic Press, 2013, pp. 157.
46. Shamloo, A., Xu, H., and Heilshorn, S. Mechanisms of
vascular endothelial growth factor-induced pathfinding by
PLATELET-RICH FIBRIN AND SOFT TISSUE WOUND HEALING 15
FOR REVIEW ONLY
NOT INTENDED FOR DISTRIBUTION
OR REPRODUCTION
endothelial sprouts in biomaterials. Tissue Eng Part A 18,
320, 2012.
47. Leach, J.K., et al. Coating of VEGF-releasing scaffolds
with bioactive glass for angiogenesis and bone regenera-
tion. Biomaterials 27, 3249, 2006.
48. Giannobile, W.V., et al. Comparative effects of platelet-
derived growth factor-BB and insulin-like growth factor-I,
individually and in combination, on periodontal regenera-
tion in Macaca fascicularis. J Periodontal Res 31, 301,
1996.
49. Bayer, A., et al. Platelet-released growth factors induce the
antimicrobial peptide human beta-defensin-2 in primary
keratinocytes. Exp Dermatol 25, 460, 2016.
50. Suzuki, S., Morimoto, N., and Ikada, Y. Gelatin gel as a
carrier of platelet-derived growth factors. J Biomater Appl
28, 595, 2013.
51. Li, Q., et al. Platelet-rich fibrin promotes periodontal re-
generation and enhances alveolar bone augmentation.
Biomed Res Int 2013, 638043, 2013.
52. Horii, K., et al. Platelet-rich fibrin has a healing effect on
chemotherapy-induced mucositis in hamsters. Oral Surg
Oral Med Oral Pathol Oral Radiol 117, 445, 2014.
53. Tunali, M., et al. In vivo evaluation of titanium-prepared
platelet-rich fibrin (T-PRF): a new platelet concentrate. Br J
Oral Maxillofac Surg 51, 438, 2013.
54. Chen, Y., et al. Improvement in the repair of defects in
maxillofacial soft tissue in irradiated minipigs by a mixture
of adipose-derived stem cells and platelet-rich fibrin. Br J
Oral Maxillofac Surg 52, 740, 2014.
55. Reksodiputro, M., et al. PRFM enhance wound healing
process in skin graft. Facial Plast Surg 30, 670, 2014.
56. Liu, B., et al. The adjuvant use of stromal vascular fraction
and platelet-rich fibrin for autologous adipose tissue
transplantation. Tissue Eng Part C Methods 19, 1, 2013.
57. Soyer, T., et al. The effect of platelet rich fibrin on growth
factor levels in urethral repair. J Pediatr Surg 48, 2545,
2013.
58. Sun, C.K., et al. Direct implantation versus platelet-rich
fibrin-embedded adipose-derived mesenchymal stem cells
in treating rat acute myocardial infarction. Int J Cardiol
173, 410, 2014.
59. Chen, Y.L., et al. Adipose-derived mesenchymal stem cells
embedded in platelet-rich fibrin scaffolds promote angio-
genesis, preserve heart function, and reduce left ventricular
remodeling in rat acute myocardial infarction. Am J Transl
Res 7, 781, 2015.
60. Sammartino, G., et al. Prevention of hemorrhagic compli-
cations after dental extractions into open heart surgery
patients under anticoagulant therapy: the use of leukocyte-
and platelet-rich fibrin. J Oral Implantol 37, 681, 2011.
61. Hoaglin, D.R., and Lines, G.K. Prevention of localized
osteitis in mandibular third-molar sites using platelet-rich
fibrin. Int J Dent 2013, 875380, 2013.
62. Suttapreyasri, S., and Leepong, N. Influence of platelet-rich
fibrin on alveolar ridge preservation. J Craniofac Surg 24,
1088, 2013.
63. Yelamali, T., and Saikrishna, D. Role of platelet rich fibrin
and platelet rich plasma in wound healing of extracted third
molar sockets: a comparative study. J Maxillofac Oral Surg
14, 410, 2015.
64. Anilkumar, K., et al. Platelet-rich-fibrin: a novel root
coverage approach. J Indian Soc Periodontol 13, 50, 2009.
65. Jankovic, S., et al. Use of platelet-rich fibrin membrane
following treatment of gingival recession: a randomized
clinical trial. Int J Periodontics Restorative Dent 32, e41,
2012.
66. Eren, G., et al. Cytokine (interleukin-1beta) and MMP
levels in gingival crevicular fluid after use of platelet-rich
fibrin or connective tissue graft in the treatment of localized
gingival recessions. J Periodontal Res 51, 481, 2016.
67. Jain, V., et al. Role of platelet-rich-fibrin in enhancing
palatal wound healing after free graft. Contemp Clin Dent
3(Suppl 2), S240, 2012.
68. Kulkarni, M.R., et al. Platelet-rich fibrin as an adjunct to
palatal wound healing after harvesting a free gingival graft:
a case series. J Indian Soc Periodontol 18, 399, 2014.
69. Femminella, B., et al. Clinical comparison of platelet-rich
fibrin and a gelatin sponge in the management of palatal
wounds after epithelialized free gingival graft harvest: a
randomized clinical trial. J Periodontol 87, 103, 2016.
70. Pathak, H., et al. Treatment of oral mucosal lesions by
scalpel excision and platelet-rich fibrin membrane grafting:
a review of 26 sites. J Oral Maxillofac Surg 73, 1865, 2015.
71. Ajwani, H., et al. Comparative evaluation of platelet-rich
fibrin biomaterial and open flap debridement in the treat-
ment of two and three wall intrabony defects. J Int Oral
Health 7, 32, 2015.
72. di Lauro, A.E., et al. Soft tissue regeneration using
leukocyte-platelet rich fibrin after exeresis of hyperplastic
gingival lesions: two case reports. J Med Case Rep 9, 252,
2015.
73. Munoz, F., et al. Use of leukocyte and platelet-rich fibrin
(L-PRF) in periodontally accelerated osteogenic orthodon-
tics (PAOO): clinical effects on edema and pain. J Clin Exp
Dent 8, e119, 2016.
74. Danielsen, P., et al. Effect of topical autologous platelet-
rich fibrin versus no intervention on epithelialization of
donor sites and meshed split-thickness skin autografts: a
randomized clinical trial. Plast Reconstr Surg 122, 1431, 2008.
75. O’Connell, S.M., et al. Autologous platelet-rich fibrin
matrix as cell therapy in the healing of chronic lower-
extremity ulcers. Wound Repair Regen 16, 749, 2008.
76. Steenvoorde, P., et al. Use of autologous platelet-rich fibrin
on hard-to-heal wounds. J Wound Care 17, 60, 2008.
77. Jorgensen, B., et al. A pilot study to evaluate the safety
and clinical performance of leucopatch, an autologous,
additive-free, platelet-rich fibrin for the treatment of re-
calcitrant chronic wounds. Int J Low Extrem Wounds 10,
218, 2011.
78. Londahl, M., et al. Use of an autologous leucocyte and
platelet-rich fibrin patch on hard-to-heal DFUs: a pilot
study. J Wound Care 24, 172, 2015.
79. Chignon-Sicard, B., et al. Efficacy of leukocyte- and
platelet-rich fibrin in wound healing: a randomized con-
trolled clinical trial. Plast Reconstr Surg 130, 819e, 2012.
80. Desai, C.B., et al. Use of platelet-rich fibrin over skin
wounds: modified secondary intention healing. J Cutan
Aesthet Surg 6, 35, 2013.
81. Danielsen, P.L., Agren, M.S., and Jorgensen, L.N. Platelet-
rich fibrin versus albumin in surgical wound repair: a ran-
domized trial with paired design. Ann Surg 251, 825, 2010.
82. Sclafani, A.P. Safety, efficacy, and utility of platelet-rich
fibrin matrix in facial plastic surgery. Arch Facial Plast
Surg 13, 247, 2011.
83. Sclafani, A.P., and McCormick, S.A. Induction of dermal
collagenesis, angiogenesis, and adipogenesis in human skin
by injection of platelet-rich fibrin matrix. Arch Facial Plast
Surg 14, 132, 2012.
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FOR REVIEW ONLY
NOT INTENDED FOR DISTRIBUTION
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84. Gorlero, F., et al. New approach in vaginal prolapse re-
pair: mini-invasive surgery associated with application of
platelet-rich fibrin. Int Urogynecol J 23, 715, 2012.
85. Soyer, T., et al. Use of autologous platelet rich fibrin in
urethracutaneous fistula repair: preliminary report. Int
Wound J 10, 345, 2013.
86. Guinot, A., et al. Preliminary experience with the use of an
autologous platelet-rich fibrin membrane for urethroplasty
coverage in distal hypospadias surgery. J Pediatr Urol 10,
300, 2014.
87. Braccini, F., et al. Modern lipostructure: the use of platelet
rich fibrin (PRF). Rev Laryngol Otol Rhinol (Bord) 134,
231, 2013.
88. Zumstein, M.A., et al. Increased vascularization during
early healing after biologic augmentation in repair of
chronic rotator cuff tears using autologous leukocyte- and
platelet-rich fibrin (L-PRF): a prospective randomized
controlled pilot trial. J Shoulder Elbow Surg 23, 3, 2014.
89. Habesoglu, M., et al. Platelet-rich fibrin plays a role on
healing of acute-traumatic ear drum perforation. J Cranio-
fac Surg 25, 2056, 2014.
90. Sclafani, A.P., et al. Modulation of wound response and
soft tissue ingrowth in synthetic and allogeneic implants
with platelet concentrate. Arch Facial Plast Surg 7, 163,
2005.
91. Andia, I., and Abate, M. Platelet-rich plasma in the treat-
ment of skeletal muscle injuries. Expert Opin Biol Ther 15,
987, 2015.
92. Cai, Y.Z., Zhang, C., and Lin, X.J. Efficacy of platelet-rich
plasma in arthroscopic repair of full-thickness rotator cuff
tears: a meta-analysis. J Shoulder Elbow Surg 24, 1852,
2015.
93. Figueroa, D., et al. Platelet-rich plasma use in anterior
cruciate ligament surgery: systematic review of the litera-
ture. Arthroscopy 31, 981, 2015.
94. Zhao, J.G., et al. Platelet-rich plasma in arthroscopic rotator
cuff repair: a meta-analysis of randomized controlled trials.
Arthroscopy 31, 125, 2015.
95. Hudgens, J.L., et al. Platelet-rich plasma activates proin-
flammatory signaling pathways and induces oxidative stress
in tendon fibroblasts. Am J Sports Med 44, 1931, 2016.
96. Del Fabbro, M., et al. Autologous platelet concentrate for
post-extraction socket healing: a systematic review. Eur J
Oral Implantol 7, 333, 2014.
97. Anuroopa, P., et al. Role and efficacy of L-PRFmatrix in
the regeneration of periodontal defect: a new perspective. J
Clin Diagn Res 8, Zd03, 2014.
98. Cieslik-Bielecka, A., et al. Microbicidal properties of leu-
kocyte- and platelet-rich plasma/fibrin (L-PRP/L-PRF):
new perspectives. J Biol Regul Homeost Agents 26(2
Suppl 1), 43s, 2012.
Address correspondence to:
Richard J. Miron, DDS, PhD
Department of Periodontology
Nova Southeastern University
Fort Lauderdale, FL 33328
E-mail: rmiron@nova.edu
Received: June 10, 2016
Accepted: September 12, 2016
Online Publication Date: October 10, 2016
PLATELET-RICH FIBRIN AND SOFT TISSUE WOUND HEALING 17
FOR REVIEW ONLY
NOT INTENDED FOR DISTRIBUTION
OR REPRODUCTION
