wound healing.pdf

Wound healing

Goutham Krishna Gorti, MD, MS, Steve Ronson, BS,R. James Koch, MD, MS*

Wound Healing and Tissue Engineering Laboratory, Division of Otolaryngology—Head and Neck Surgery,

Stanford University Medical Center, Stanford, CA 94305-5328, USA

A precise knowledge of wound healing is central

to the science of facial plastic surgery. Wound repair

represents a basic response of the biological organism

for successful restoration and maintaining tissue

integrity in the event of a biological insult in the

form of a disease or starvation [1]. Wound healing in

mammalian tissues is an essential process in the

maintenance of the body integrity [2]. The biological

objectives of wound healing are to restore the epithe-

lial integrity and the tensile strength of the subepi-

thelial connective tissue [3]. Three mechanisms are

involved in achieving these objectives, namely, epi-

thelialization, wound contraction, and extracellular

matrix synthesis. The cellular processes involved in

these mechanisms for the most part perform in a

controlled fashion, eventually leading to the forma-

tion of scar [4]. In contrast, the early gestational fetal

wound healing mechanisms do not lead to the forma-

tion of scar tissue.

The cellular biology and biomolecular mech-

anisms underlying fetal wound repair differ from

those in the adult animal [5]. The most striking

features in fetal wound healing are the lack of poly-

morphonuclear leucocyte (PML) cells and the abund-

ance of macrophages in the cellular infiltrate. The

acute inflammatory response is minimal compared to

the adult or newborn wounds [6]. Also in adult

mammals, the general mechanism of wound healing

is a study of repair in contrast to the regeneration seen

in more primitive vertebrates. This often involves

tissue regeneration, accomplished by the replacement

of mature cells through cell proliferation or the

replacement of cells, but not the whole organs, from

immature stem cells. Epimorphic regeneration (re-

placement of entire limbs after amputation) is seen

in some lower order mammals; it is exemplified by the

replacement of antlers and the closure of ear holes in

rabbits, where a through-and-through hole placed in

the ear is healed to completely normal tissue and is a

result of regeneration and replacement of multiple

tissues, not wound repair [2].

Biology of wound healing

Wound healing is a sequential cascade of overlap-

ping processes, which occur in a careful, regulated,

and reproducible manner, and which correlate with

the appearance of different cell types in the wound

[1]. Tissue injury initiates bleeding, coagulation, in-

flammation, cell replication, angiogenesis, epithelial-

ization, and matrix synthesis. Wound healing is

comprised of four major phases: hemostasis (minutes),

the inflammatory phase (3 days postinjury), the pro-

liferative phase (3 to 12 days postinjury), and the

remodeling phase (months postinjury).

Tissue injury is characterized by injury to the mi-

crovasculature resulting in an extravasation of blood

in to the wound site. The response by the tissues is

both vascular and cellular.

Vascular response (hemostasis)

Coagulation cascade is initiated, resulting in the

formation of thrombin to convert fibrinogen to fibrin.

The complement and kinin cascades are also activated.

They release chemotactic and vasoactive mediators,

which induce transient arteriolar vasoconstriction last-

1064-7406/02/$ – see front matter D 2002, Elsevier Science (USA). All rights reserved.

PII: S1064 -7406 (02 )00004 -4

* Corresponding author.

E-mail address: [email protected] (R.J. Koch).

Facial Plast Surg Clin N Am 10 (2002) 119–127

ing a few minutes, followed by vasodilatation second-

ary to the local synthesis of prostaglandins. Vascular

permeability is increased by the action of bradykinin,

histamine, and serotonin, resulting in a leakage of

plasma proteins and fluid into the interstium. Presence

of endothelial injury with an exposure of the under-

lying collagen causes the platelets to adhere to the

basement membrane. This platelet activation gener-

ates thromboxane A2 (TXA2), which is responsible for

the initial vasoconstriction, and adenosine diphos-

phate (ADP), which facilitates the aggregation of

additional platelets in the growing clot. Mediators

released by coagulation, complement pathways, and

platelets induce the influx of inflammatory cells.

Cellular response (acute inflammatory phase)

Neutrophils (PMN) are the first cells seen at the

site of the injury. Their main function is phagocytosis

of the microorganisms and prevention of infection.

They help in the debridement of the devitalized tissue.

During this phase, neutrophils migrate to the site of the

injury to phagocytose the bacteria. As noted earlier,

this migration is seldom observed in fetal wound

healing. Following the digestion, the PMN cells die

and release their intracellular content. Lymphocytes

arrive next at the site of injury releasing lymphokines.

Two populations of T cells are implicated in wound

healing: cells bearing the all T-cell marker and the

T-suppressor/cytotoxic subset. Depletion of these cells

enhances wound-breaking strength.

Monocytes start migrating to the site of injury

three to five days postinjury. The monocytes con-

vert to macrophages. The macrophage is the key

component of wound repair. Macrophages actively

participate in three aspects of tissue remodeling:

(1) production of growth factors, which influence

the growth and behavior of fibroblasts; (2) produc-

tion of the angiogenic factor, which helps in the

revasularization of the wound; and (3) and produc-

tion of factors that modulate proteins that make up

the extracellular matrix by other cells within the lo-

cal environment.

Proliferative phase

Fibroblast proliferation

Cellular proliferation involves fibroblast prolifera-

tion and angiogenesis. Fibroblast proliferation occurs

at the end of the first week following the injury. It

originates from the nearby connective tissue cells.

Growth factors released by the macrophages stimu-

late the mitosis and proliferation of the fibroblasts

and collagen synthesis. The fibroblasts migrate and

cross into the wound and form an adhesive contact

with fibrin, collagen fibers, and fibronectin. They

establish a lattice for collagen synthesis.

Angiogenesis

When oxygen delivery is impaired locally, as in a

tissue in which perfusion has been interrupted by

injury, the primary response is angiogenesis with the

sprouting of new blood vessels. Angiogenesis is

essential to restore the blood flow, to reoxygenate

the wound surface, and to promote wound healing. It

becomes prominent on the fourth day following

injury. The complex process of angiogenesis begins

when cells within a tissue respond to hypoxia by

increasing their production of vascular endothelial

growth factor (VEGF). VEGF is exclusively mito-

genic to endothelial cells and is believed to be an

important factor in wound healing [7]. VEGF is

secreted by macrophages and binds to cognate recep-

tor tyrosine kinases (VEGFR1 and VEGFR2) located

on the surface of vascular endothelial cells. Receptor

ligation triggers a cascade of intracellular signaling

pathways that initiate angiogenesis [8]. The endothe-

lial cells proliferate and give rise to capillary buds at

the wound surface. The buds build a network of loops

that join other buds to form a capillary bed.

Epithelialization

Epithelialization starts within hours after injury.

Epithelial cells move from the edge of the tissue

across the defect. This process is activated by growth

factors secreted by the platelets initially and by

macrophages later.

Remodeling phase

Matrix formationCollagen. Collagen is a product of fibroblasts and

helps in developing the wound strength. There are

three important stimuli for the fibroblasts to produce

collagen: (1) high lactate content in the wound, (2)

adequate oxygen levels, and (3) growth factors,

especially transforming growth factor-beta (TGF-b)released from platelets and macrophages. The rate of

collagen synthesis is maximal in the first two weeks

and it reaches a peak between three to four weeks.

Fibronectin. Fibronectin is produced by fibroblasts,

platelet, and endothelial cells. Fibronectin forms the

substrate for (1) migration and ingrowth of cells and

(2) binding macromolecules, eg, collagen, fibrin,

heparin, and proteoglycans. It acts as a template for

the production of collagen and contributes to the

debridement of wounds and later remodeling.

G.K. Gorti et al. / Facial Plast Surg Clin N Am 10 (2002) 119–127120

Ground substance. Ground substance is composed

of proteoglycans, glycosaminoglycans, and mucopro-

teins produced by fibroblasts. Proteoglycans are the

major components of the ground substance also

called the extracellular matrix.

Collagen remodeling

Collagen remodeling is the last phase of the repair

process and begins three weeks postinjury and lasts for

months. Wound remodeling is the result of increased

cross-linking of collagen, breakdown of excess col-

lagen, and regression of vascularity. Collagenase is

the major enzyme responsible for remodeling. It is

secreted by fibroblasts and macrophages.

Wound contraction

The process of wound contraction involves the

movement of existing tissue at the wound edge, not

formation of new tissue. Wound contraction is be-

lieved to be mediated by fibroblasts moving along

collagen fibers, causing the fibers to move together.

Growth factors

Growth factors are critical to normal cellular

function [9]. They are defined as glycoproteins or

peptides promoting cell growth, division, migration,

and recruitment into injured tissue. They may be

secreted in a paracrine or autocrine fashion [10].

They are released in all phases of wound healing:

hemostasis, inflammation, proliferation, and remod-

eling. They contribute to wound healing by con-

trolling the proliferation and migration of cells that

modulate epithelialization, angiogenesis, and col-

lagen metabolism [7]. Growth factors are produced

by a variety of cells including platelets, macro-

phages, neutrophils, endothelial cells, and fibro-

blasts. The action or release of growth factors

may explain the clinical characteristics of keloid

scar tissue [11–16]. There is a renewed interest in

growth factors in plastic surgery because of the fact

that by manipulating the growth factors it may be

possible to modify the wound healing process in

different clinical states. The major growth factors

that have a direct effect on the growth of fibro-

blasts are fibroblast growth factor (FGF), TGF-b,and platelet-derived growth factor (PDGF). The

major growth-factor proteins that have an angio-

genic effect are the VEGF and cysteine-rich protein

61 (Cyr61). Cyr61 is a heparin-binding, extracellu-

lar matrix-associated protein, and is a signaling

molecule with functions in cell migration, adhesion,

and proliferation

Following is a brief description of each growth

factor and the role it plays during the process of

wound healing.

Fibroblast growth factor

Of the nine different types of FGF, there are three

that have a dominant role in wound healing: acidic

FGF (FGF-1), basic FGF (FGF-2), and keratinocyte

growth factor (KGF). FGF-1 and FGF-2 are single-

chain polypeptides with a molecular weight of 14 to

18 kd. Multiple cells, including dermal fibroblasts,

secrete them. Their target cells are those of meso-

dermal and neuroectodermal origin. In general they

induce and accelerate the proliferation of fibroblasts,

vascular and capillary endothelial cells, keratinocytes,

chondrocytes, and myoblasts. In specific fibroblast

tissue culture, they are mitogenic, promote cell sur-

vival, inhibit collagen production, and stabilize cellu-

lar phenotypes [17,18]. Type I collagen, which is

excessive in a keloid scar, is inhibited with the ap-

plication of bFGF to keloid dermal fibroblast cul-

tures in vitro [19].

Transforming growth factor-beta

Transforming growth factor-beta 1 (TGF-b1) is

the predominant isoform in humans. It is a 25-kd

dimer produced by multiple cells including fibro-

blasts, platelets, macrophages, lymphocytes, and

endothelial cells [11]. It stimulates matrix proteins

(eg, collagen), inhibits protease production, and

enhances mitogenesis [14,20,21]. During wound

healing TGF-b1 stimulates the migration of inflam-

matory cells and promotes the synthesis of extracel-

lular matrix (collagen-I, glycosaminoglycans, and

fibronectin). It has a regulatory effect on other growth

factors (FGF, PDF, and EGF) [7]. One in vitro study

suggests that keloid fibroblasts secrete more TGF-b1than normal dermal fibroblasts and may be integral to

keloid scar pathophysiology [5]. Application of

TGF-b1 increases collagen production in keloid der-

mal fibroblasts in culture relative to normal cells

[15,22]. This response is reversed with the addition

of anti–TGF-b1 antibodies [11].

Platelet-derived growth factor

Platelet-derived growth factor (PDGF) is stored in

the alpha granules within platelets. It is composed of

two polypeptide chains (dimer) with a molecular

weight of 30,000 d [7]. PDGF has an important role

to play in the synthesis of connective tissue matrix

and wound remodeling. It has a mitogenic effect on

G.K. Gorti et al. / Facial Plast Surg Clin N Am 10 (2002) 119–127 121

fibroblasts, and it stimulates the synthesis of glycos-

aminoglycans and proteoglycans [7].

Vascular endothelial growth factor

Vascular endothelial growth factor (VEGF) is a

potent mitogenic cytokine that has been identified as

the principal polypeptide growth factor influencing

endothelial cell (EC) migration and proliferation.

Ordered progression of these two processes is an ab-

solute prerequisite for initiating and maintaining the

proliferative phase of wound healing. VEGF belongs

to the PDGF family. It is exclusively mitogenic to

endothelial cells. It is essential for angiogenesis in

health and pathophysiology. Nitric oxide (NO) gen-

erated by inducible nitric oxide synthase enhances

VEGF synthesis in vascular smooth muscle cells,

and NO and modified low-density lipoprotein aug-

ment VEGF production in macrophages [23]. The

selective angiogenic action of VEGF on endothelial

cells may play an important role in tissue repair.

Cysteine-rich protein 61

Cyr61 is a heparin-binding, extracellular matrix-

associated protein. Cyr61 is capable of multiple

functions, including induction of angiogenesis in

vivo. Purified Cyr61 mediates cell adhesion and

induces adhesive signaling, stimulates cell migration,

enhances cell proliferation, and promotes cell sur-

vival in both fibroblasts and endothelial cells. Cyr61

is believed to regulate the expression of a genetic

program for wound healing in fibroblasts. The Cyr61

gene is inducibly expressed in granulation tissue

during wound repair, and it regulates the expression

of genes involved in angiogenesis, inflammation,

matrix remodeling, and cell-matrix interactions [24].

Wound healing research in plastic surgery

Maximizing nutrition, preventing infection, and

using various suture and flap techniques are some of

the methods for achieving optimal wound healing.

However, aberrant wound healing is a significant

problem for many surgical patients. On one extreme,

patients with diabetes, cancer, or poor nutritional

status, or who have recently undergone radiation

therapy, frequently have wounds that are difficult to

heal. Conversely, apparently healthy patients may

have aberrant, exuberant healing in the form of

hypertrophic or keloid scar. The latter is characterized

by benign dermal growth with excess deposition of

collagen beyond the original wound margins. It is

possible that aberrant wound healing may arise from

a locally insufficient concentration or overproduction

of certain types of growth factors. Because of the

many antagonisms of growth-factor activities, it may

be possible to correct a deficiency or overabundance

by the modulation of wound cells.

The authors have focused their work in their

wound healing laboratory primarily on four areas:

(1) the selection and use of a serum-free in vitro mod-

el for the growth of fibroblasts, (2) analysis of growth

factors produced during cell culture of fibroblasts and

their influence in the presence of other modulators,

(3) evaluation of external modulators on the growth

of fibroblasts, and (4) drawing conclusions on the

overall effects of external modulators on wound heal-

ing and keloid formation.

Serum-free in vitro model

The establishment of human cell lines in vitro is

one method for studying normal and keloid-producing

dermal fibroblasts (NF, KF) at a cellular level [9]. In

contrast to normal fibroblasts, keloid fibroblasts repre-

sent a useful model for the study of excessive, aberrant

wound healing. Benefits of this in vitro methodology

include a controlled environment, fewer variables than

in vivo techniques, and objective assessment of treat-

ment parameters [11]. A negative aspect of the usual

methodology, however, is the presence of serum com-

ponents, which are necessary to sustain growth of the

cells. Standard culture techniques allow measurement

of certain products, such as collagen or fibronectin, but

may confound growth-factor measurements because

of background levels present in the media. Thus, the

use of a serum-free medium eliminates this variable.

The measurement of growth factors in viable cell

culture is sparse in the literature [12]. Only recently

has serum-free growth of keloid-producing fibroblasts

been established in such a medium [17,25].

The authors have evaluated dermal fibroblasts from

tissues that span the range of the wound-healing

phenomenon: fetal fibroblasts for scar-free healing,

normal fibroblasts for normal healing, irradiated fibro-

blasts for impaired healing, and keloid-producing

fibroblasts for exuberant wound healing. These experi-

ments, using a serum-free model, support the viability

and proliferation of fibroblasts and also help in the

assay of growth factors known to figure prominently

in the wound-healing process [26]. Such methods

have been adopted previously, although serum-free

conditions have not been used past the incubation

phase of cell culture. A potential disadvantage of

serum-free media is that fibroblast proliferation char-

acteristics and viability are generally not as good as


with serum-based models. In these experiments,

the authors primarily have used UltraCULTURE,

which is described as a general-purpose serum-free

medium for the proliferation of both adherent and

nonadherent cells.

Methods

Fibroblast primary cultures

Fibroblast primary cell lines are established from

skin obtained from operative specimens (keloid tis-

sue, normal skin, and irradiated skin). Permission to

use operative specimens that would otherwise be

discarded is obtained from the Human Subjects

Committee of Stanford University. Fetal dermal

fibroblasts are obtained from a cell repository.

To evaluate the growth of the fibroblasts and to

analyze their production of growth factors, the

authors use the commercially available serum-free

media, UltraCULTURE. Cell lines from each spec-

imen are established and propagated in a serum-free

environment (Fig. 1). The specimens are then stored

in a humidified incubator at 37�C with a 5% CO2

atm. The desired fibroblast count is achieved follow-

ing repeated passages when confluence is reached.

Cell counting and growth-curve generation

At each predetermined time point, cell-free super-

natant is collected from the testing wells and is

analyzed for growth-factor production. Concentra-

tions of growth factors are calculated on a per-cell

basis and compared to normal levels.

Cell counts are performed using the WST-1 assay

(Boehringer Mannheim, Indianapolis, IN) for growth-

curve generation. The WST-1 assay is a colorimetric

assay used in the quantification of cell proliferation

and cell viability. Growth curves are generated from

the data, and population-doubling times are calcu-

lated from the growth curves. Double-sided t tests are

used to analyze the data for statistical significance.

Growth-factor production by fetal, keloid, and

normal dermal fibroblasts

Fetal wounds heal without histologic evidence of

scarring [27]. Fibroblasts are the main effector of scar-

Fig. 1. Methods.


free healing in fetal tissue and this healing can occur

outside the fetal environment [2–5]. Several studies

suggest that differences in autocrine growth-factor

production exist between adult and fetal wounds

[6,7,9–12]. The most promising and best studied of

these growth factors include TGF-b1 and bFGF.

In contrast to fetal wound healing, keloids are

characterized by formation of exuberant scar tissue

that does not flatten over time. They are associated

with an abnormal proliferation of fibroblasts as well as

overproduction of extracellular matrix and collagen

[13,14]. Treatment for keloid scars is problematic with

no single modality producing uniformly satisfactory

results. Evidence suggests that keloid formation may

be caused in part by deranged growth-factor activity.

The authors evaluated the autocrine growth-factor

production by dermal fibroblasts from tissues that

span the range of the wound-healing phenomenon. It

is possible that keloids may be treated or prevented by

correcting locally insufficient or excessive concentra-

tions of growth factors. Likewise, by understanding

the mechanism of the scar-free healing exhibited by

fetal wounds, it may be possible to manipulate the

growth-factor milieu to simulate this process in

wounds of the mature dermis. Fetal and keloid cells

produce significantly higher levels of TGF-b1 con-

centration per cell than normal adult fibroblasts. Fetal

fibroblasts produce higher levels of bFGF than normal

adult fibroblasts; this could in turn explain to some

extent the lack of scar tissue formed in fetal wounds.

The authors use the serum-free model to quantita-

tively measure autocrine growth-factor production by

cells that underlie clinically different types of wound

healing, potentially providing information that will

allow improved treatment and prevention of undesir-

able scarring (Table 1).

Modulators

Modulators are external agents that influence the

wound-healing mechanism by altering the autocrine

growth-factor milieu, thereby allowing optimal wound

healing. Because of the many antagonisms of growth-

factor activities, it may be possible to correct a defi-

ciency or overabundance with local application of

another factor that modulates the wound cells’

growth-factor production profile. Once a modulator’s

(or combination of modulators thereof ) autocrine

growth-factor stimulatory properties are known, it

can be placed into a wound to achieve the desired

healing response. Routine wound application of

recombinant-produced or autologous-derived growth

factors is expensive. Using obtainable modulators,

such as copper tripeptide, as cytokine stimulators cir-

cumvents this problem.

In the larger scheme, using cytokine manipula-

tions to vary the makeup of ECM components (such

as collagen) may have a great impact in precisely

controlling the wound-healing process. For example,

if a person with diabetes has a nonhealing ulcer, the

wound can be treated with a modulator that stimulates

production of an angiogenic growth factor, which will

cause local development of blood vessels. Finally,

anyone undergoing surgery may benefit from wound

treatment with a modulator that causes production of

a growth factor leading to an increase of collagen

with tighter bundles, thus forming a smaller yet

stronger scar.

The authors have tested several wound-healing

modulators and briefly discuss the results and clinical

implications of each (Table 2).

Table 1

Unstimulated autocrine growth-factor production by

fibroblasts

NF FF KF IF

TGF-b1 "" """" """" "bFGF "" """" " "Clinical

significance

Normal

healing

Scar-free

healing

Exuberant

healing

Poor

healing

Abbreviations: DF, normal fibroblasts; FF, fetal fibroblasts;

IF, irradiated fibroblasts; KF, keloid fibroblasts; ", increase;#, decrease.

Table 2

Effects of modulators tested at the Wound Healing & Tissue Engineering Laboratory, Stanford University Medical Center,

Stanford, CA

Modulators Cells Growth factors levels Possible clinical effects

Copper tripeptide NF, KF # TGF-b1 # Excessive scar formation

Tretinoin NF " bFGF " Skin-tightening effects

Superpulsed CO2 laser NF, KF " bFGF, # TGF-b1 " Normal healing

Silicone gel FF, NF " bFGF # Hypertrophic scar tissue

Tamoxifen KF # TGF-b1 " Healing in keloids

Abbreviations: DF, normal fibroblasts; FF, fetal fibroblasts; KF, keloid fibroblasts; ", increase; #, decrease.


Copper tripeptide and tretinoin

Copper tripeptide and tretinoin influence growth-

factor secretion in normal and keloid fibroblasts and

may result in a decrease of excessive scar formation.

Normal fibroblasts treated with tretinoin produce

more bFGF than do controls, and this may partially

explain the clinically observed tightening effects of

tretinoin. Normal and keloid-producing fibroblasts

treated with copper tripeptide secreted less TGF-b1than did controls, suggesting a possible clinical use

for decreasing excessive scar formation [26].

Superpulsed CO2 laser

Superpulsed CO2 (SCO2) laser energy, a potential

wound-healing modulator that stimulates neocollagen

production, stimulates bFGF and inhibits TGF-b1production by normal and keloid fibroblasts. SCO2

enhances fibroblast replication, stimulates bFGF, and

inhibits TGF-b1 secretion. Given the function of

these growth factors, the application of SCO2 may

support normalized wound healing. These findings

may explain the beneficial effects of laser resurfacing

on a cellular level and support the use of SCO2 in the

management of keloid scar tissue [9].

Tamoxifen

Evidence suggests keloid scar formation may be

mediated, in part, by deranged growth-factor activity

of TGF-b1. The higher level of TGF-b1 produced by

keloid cells compared with fetal fibroblasts may be

related to aberrant wound healing seen with keloids.

Tamoxifen may lead to improved wound healing in

keloids by decreasing the expression of TGF-b1 [28].

Silicone gel

Topical silicone gel shows clinical promise in

hypertrophic and keloid scar treatment. There are

specific morphological and functional differences

between keloid scars and hypertrophic scars. The

authors’ results suggest that silicone gel stimulates

bFGF production by normal and fetal dermal fibro-

blasts. An increased level of bFGF would be expected

to reduce collagen proliferation. No silicone-related

effects are observed with keloid cells in this study.

The authors postulate that silicone gel treats and

prevents hypertrophic scar tissue, which contains

histologically normal fibroblasts, by modulating

expression of growth factors such as bFGF [29].

Irradiated fibroblasts

Radiation therapy for head and neck cancer per-

manently damages tissue in the line of treatment. The

authors conducted a study to establish a serum-free

protocol to evaluate the growth of irradiated fibro-

blasts and to analyze the levels of bFGF and TGF-bcompared with normal fibroblasts. The results of this

and previous studies suggest that cells from irradiated

tissue have permanent and detrimental cellular

changes. This study provides an effective model for

the first-line evaluation of agents to improve wound

healing and helps establish standard levels of fibro-

blast bFGF and TGF-b production for irradiated

fibroblasts [30].

Recent trends

Recently, autologous whole blood products have

been used perioperatively to hasten the wound-

healing process during cosmetic surgery. These prod-

ucts are based on the model in which the blood is

obtained during the immediate preoperative period

and processed into platelet-rich plasma using a differ-

ential centrifugation process in a conventional auto-

transfusion machine [31]. Platelet gels are created by

combining the platelet-rich plasma with thrombin and

calcium chloride [32,33]. The platelet gels are rich in

cytokines and growth factors and have been found to

accelerate wound healing and hemostasis. Among the

growth factors that are released from this gel are

the platelet-derived growth factor and transform-

ing growth factor, which accelerate wound healing

[34,35]. The main drawback has been the expense of

installing autotransfusion machines in office-based

or ambulatory surgical facilities and the employment

of qualified technicians to process the machines.

Several commercial systems are in the experimental

stages, which may increase the cost-effectiveness in

the near future.

Fibrin glue, originally described in 1970, is

formed by polymerizing fibrinogen with thrombin

and calcium [36]. It can be prepared using donor

plasma or cryoprecipitate. The fibrin glue formed

from cryoprecipitate has been found to be more

stable. Fibrin glue has been well established as an

excellent hemostatic agent. The main drawback is the

risk of disease transmission and lack of a cost-

effective method of preparing this product in a stand-

ardized fashion. Man, Plosker, and Winland-Brown

demonstrate the use of both autologous fibrin glue

and platelet gel in cosmetic surgical procedures, using

a commercially available system for the rapid proc-


essing of these products in the operating room. In

combination, these two products are highly effective

in controlling bleeding during surgery and hastening

the process of wound healing. The role of autologous

fibrin glue is primarily obtaining hemostasis, and

platelet gel may offer significant advantages in accel-

erating the postoperative wound healing [31].

References

[1] Falcone PA, Caldwell MD. Wound metabolism. Clin

Plast Surg 1990;17(3):443–56.

[2] McBerty BA, Clark LD, Zhang XM, Blankerton EP,

Heber-Katz E. Genetic analysis of a mammalian

wound-healing trait. Proc Natl Acad Sci U S A 1998;

95(20):11792–7.

[3] Wolf N. The natural history of acute inflammation

II: wound healing. In: Horne T, editor. Cell tissue and

disease. 3rd Edition. Philadelphia: Saunders; 2000.

p. 113–29.

[4] Glat PM, Longaker MT. Wound healing. In: Aston

SJ, Beasley RW, Thorne CHM, editors. Grabb and

Smith’s plastic surgery. 5th edition. Philadelphia,

PA: Lippincott-Raven; 1997. p. 3–12.

[5] Longaker MT, Peled ZM, Chang J, Krummel TM. Fe-

tal wound healing: progress report and future direc-

tions. Surgery 2001;130(5):785–7.

[6] Adzick NS, Harrison MR, Glick PR, Beckstead JH,

Villa RL, Scheuenstuhl H, et al. Comparison of fetal,

newborn, and adult wound healing by histologic, en-

zyme-hisotchemical, and hydroxyproline determina-

tions. J Pediatr Surg 1985;20:315–9.

[7] Hom DB. Growth factors in wound healing. Otolar-

yngol Clin North Am 1995;28(5):933–53.

[8] Semenza GL. Regulation of hypoxia-induced angio-

genesis: a chaperone escorts VEGF to the dance. J Clin

Invest 2001;108(1):39–40.

[9] Nowak KC, McCormack M, Koch RJ. The effect of

superpulsed carbon dioxide laser energy on keloid and

normal dermal fibroblast secretion of growth factors: a

serum-free study. Plast Reconstr Surg 2000;105(6):

2039–48.

[10] Brew EC, Mitchell MB, Harken AH. Fibroblast growth

factors in operative wound healing. J Am Coll Surg

1995;180(4):499–504.

[11] Younai S, Nichter LS, Wellisz T, et al. Modulation of

collagen synthesis by transforming growth factor-beta

in keloid and hypertrophic scar fibroblasts. Ann Plast

Surg 1994;33(2):148–51.

[12] Chau D, Mancoll JS, Lee S, et al. Tamoxifen down-

regulates TGF-beta production in keloid fibroblasts.

Ann Plast Surg 1998;40(5):490–3.

[13] Babu M, Diegelmann R, Oliver N. Keloid fibroblasts

exhibit an altered response to TGF-beta. J Invest Der-

matol 1992;99(5):650–5.

[14] Border WA, Noble NA. Transforming growth factor

beta in tissue fibrosis. N Engl J Med 1994;331(19):

1286–92.

[15] Peltonen J, Hsiao LL, Jaakkola S, et al. Activation of

collagen gene expression in keloids: co-localization of

type I and VI collagen and transforming growth factor-

beta1 mRNA. J Invest Dermatol 1991;97(2):240–8.

[16] Tredget EE, Nedelec B, Scott PG, Ghahary A. Hyper-

trophic scars, keloids, and contractures. The cellular

and molecular basis for therapy. Surg Clin North Am

1997;77(3):701–30.

[17] Hong R, Lum J, Koch RJ. Growth of keloid-producing

fibroblasts in commercially available serum-free me-

dia: a comparative study. Otolaryngol Head Neck Surg

1999;121(4):469–73.

[18] Gospodarowicz D. Biological activities of fibroblast

growth factors. Ann N Y Acad Sci 1991;638:1–8.

[19] Tam EM, Rouda S, Greenbaum SS, Moore JH Jr, Fox

JW 4th, Sollberg S. Acidic and basic fibroblast growth

factors down-regulate collagen gene expression in ke-

loid fibroblasts. Am J Pathol 1993;142(2):463–70.

[20] Garner WL. Epidermal regulation of dermal fibroblast

activity. Plast Reconstr Surg 1998;102(1):135–9.

[21] Raghow R, Postlethwaite AE, Keski-Oja J, Moses HL,

Kang AH. Transforming growth factor-beta increases

steady state levels of type I procollagen and fibronectin

messenger RNAs posttranscriptionally in cultured

human dermal fibroblasts. J Clin Invest 1987;79(4):

1285–8.

[22] Kikuchi K, Kakano T, Takehara K. Effects of various

growth factors and histamine on cultured keloid fibro-

blasts. Dermatol 1995;190(1):4–8.

[23] Dulakk J, Jozkowicz A, Dichtl W, Alber H, Schwar-

zacher SP, Pachinger O, et al. Vascular endothelial

growth factor synthesis in vascular smooth muscle cells

is enhanced by 7-ketocholesterol and lysophosphatidyl-

choline independently of their effect on nitric oxide

generation. Atherosclerosis 2001;159(2):325–32.

[24] Chen CC, Mo FE, Lau LF. The angiogenic factor

Cyr61 activates a genetic program for wound healing

in human skin fibroblasts. J Biol Chem 2001;276(50):

47329–37.

[25] Koch RJ, Goode RL, Simpson GT. Serum-free keloid

fibroblast cell culture: an in vitro model for the study

of aberrant wound healing. Plast Reconstr Surg 1997;

99(4):1094–8.

[26] McCormack M, Nowak KC, Koch RJ. The effect of

copper tripeptide and tretinoin on growth factor pro-

duction in a serum-free fibroblast model. Arch Facial

Plast Reconst Surg 2001;3(1):28–32.

[27] Mackool RJ, Gittes GK, Longaker MT. Scarless heal-

ing: the fetal wound. Clin Plast Surg 1998;25:357–65.

[28] Mikulec AA, Hanasono MM, Lum J, Kadleck JM, Kita

M. Koch effect of tamoxifen on TGF-b1 production by

keloid and fetal ibroblasts. Arch Facial Plast Reconst

Surg 2001;3:111–4.

[29] Hanasono MM, Lum J, Carroll LA, Mikulec AA, Koch

RJ, Silicon gel increases basic fibroblast growth factor

levels in fibroblast cell culture. Arch Facial Plast Re-

const Surg, In press.


[30] Lonergan DM, Mikulec AA, Hanasono MM, Kita M,

Koch RJ. Using a novel serum-free method to evaluate

the effect of bFGF on human dermal irradiated fibro-

blasts. Plast Reconstr Surg. Submitted for publication.

[31] Man D, Plosker H, Winland-Brown JE. The use of

autologous platelet-rich plasma (platelet gel) and autol-

ogous platelet-poor plasma (fibrin glue) in cosmetic

surgery. Plast Reconstr Surg 2001;107(1):229–37.

[32] Oz MC, Jeevanandam V, Smith CR, et al. Autologous

fibrin glue from intraoperatively collected platelet-rich

plasma. Ann Thorac Surg 1992;53:550.

[33] Redder GD, Hood AG, Hill AG, et al. Perioperative

autologous sequestration: I. Physiology, phenomena

and art. Am Acad Cardiovasc Perfusion 1993;14:118.

[34] Pierce GF, Mustoe TA, Lingelbach J, et al. Platlet

derived growth factor and transforming growth factor-

beta enhance tissue repair activities by unique mech-

anisms. J Cell Biol 1989;109:429.

[35] Pierce GF, Mustoe TA, Altrock BW, Deuel TF, Tho-

mason A. Role of platelet-derived growth factor in

wound healing. J Cell Biochem 1991;45:319.

[36] Matras H. Die Wirkumgen verschiedener Fibrin-

praparate auf Kontinuitat-strennungen der Rattenhaut.

Osterr Z Stomatol 1970;67:338.


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