The Role of the Autologous Platelet-Derived Growth Factor in the Management of Decubitus Ulcer

B. Aminian MD, M. Shams MD, B.
Karim-Aghaee MD, M. Soveyd MD, Gh. R. Omrani MD

Department of
Internal Medicine, Shiraz University of Medical Sciences, Shiraz,
Iran

Abstract

Background/Objective-Decubitus ulcer is an
important medico-surgical problem. Medical therapies
mostly lead to failure and many patients with decubitus
ulcer will ultimately need reconstructive surgery after
long morbidity. The aim of our study was to evaluate the
effectiveness of autologous platelet-derived growth
factor in the healing of these ulcers when compared to
conventional therapies.
Methods-This study was a
randomized control-designed therapeutic clinical trial.
Fifteen patients with twenty decubitus ulcers were
randomly assigned to treatment and control groups. Eleven
wounds were randomized to treatment groups and received
general wound care, dressing and PDGF, and nine were
subjected to controlled wound care with the same general
management and dressing for two weeks. Ulcer parameters
were recorded on the first day and then every three days
for two weeks. These parameters were compared in the two
groups and data-analyzed by student t-test,
Kolmogorov-Smirnov goodness of fit test (K-S), Fisher
exact test and analysis of variance (ANOVA). P values
less than 0.05 were considered statistically significant.
Results-In the treatment group,
four patients had complete healing and in others there
was reduction in the size of the ulcer. The reduction in
the wound area among treatment and control groups was
3.90±2.42 and -1.44±2.24 cm²
respectively (p=0.001). Reduction in the wound depth in
the treatment group compared to the control group was
3.45±2.54 and –2.22±3.76 mm respectively
(p=0.001). A seventy percent reduction in the wound area
in the treatment group compared to the same change in the
control group was 70.80±29.81% and 29.53±49.29%
respectively (p=0.001), and a seventy percent reduction
in wound depth in the treatment group compared to this
change in control group was 70.83±30.56% and
–47.68±72.68% (p=0.001). Conclusion-We conclude that
topically applied autologous platelet-derived growth
factor better promotes wound healing in patients with
decubitus ulcers compared to those who receive
conventional therapy, and renal failure and sepsis do not
suppress the wound healing process in treated patients.

Introduction

Decubitus ulcer is one of
the dreaded problems in patients confined to bed for a longer
periods of time. Most of these patients have underlying
medico-surgical problems, making management both difficult and
expensive.¹ It has been found that about 5-8% of
patients admitted to a hospital in London develop decubitus
ulcer. Its frequency is as high as 60% in patients with
underlying orthopedic disease. In one third of cases these ulcers
are multiple and in elderly patients this occurs in fifty percent
of cases.² Risk factors for decubitus ulcers are
immobility, longstanding pressure applied to a part of the body,³
increased local temperature,⁴ drugs,²
underlying neurologic and cardio-vascular diseases,⁵
nutritional status, increased age^6,7 and decreased
fibronectin as an agent that promotes vascularization and
epithelialization in ulcers.⁸ Ischemic damage to
capillary membrane, increased capillary permeability, edema and
cellular infiltrate constitute the chain of events that produces
cell necrosis and ulcer.⁹ Recently, the role of growth
factors in the healing process has received considerable
attention, especially the experimental use of autologous
platelet-derived growth factors in ulcer healing. Polypeptide
growth factors are a class of biological material that promote
cell proliferation, alone or in concert, with binding to specific
cell surface mediators. Molecules classified as growth factors
may have additional effects on cell differentiation, motility and
matrix synthesis. In vitro demonstrations of these properties
have led to the conclusion that such growth factors might play an
important role in wound healing.^10,11 In the following
study we present a new approach in the treatment of decubitus
ulcer, utilizing the circulatory platelets as a source of
autologous locally acting growth factors for stimulating the
repair and healing of ulcer.

Patients and Methods

Research design and patient selection:

This study is a controlled-design, therapeutic
clinical trial with simple random sampling. From all patients
with decubitus ulcer who were admitted to the teaching hospitals
of Shiraz University of Medical Sciences, eighteen patients with
twenty-five decubitus ulcers were entered into the initial study.
Three patients died because of their underlying disease, so study
continued with fifteen patients and twenty decubitus ulcers.
Eleven ulcers were randomized into treatment group (Group I), and
nine ulcers in control group (Group II). The inclusion criteria
were:

1. Minimal depth and surface area
of ulcer, 2 mm and 2 cm², respectively.

2. Absence of active infection and
necrosis of ulcer.

3. Normal peripheral platelet
count (>150.000/ mm³).

4. Reliability and cooperation
of the patient.

5. Sacral and buttock location
of the ulcer.

The age and sex of the patients and their
underlying diseases had no role in patient selection. The
randomization of the patients was on the basis of their
hospitalization. The first patient (ulcer) was put in the
treatment group (Group I) and the second patient (ulcer) was
assigned to control group (Group II). If a patient had two ulcers
with similar conditions, they were randomized to the treatment or
control groups with lotting. Patients randomized to the treatment
group (Group I) received PDGF and dressing, but those who were
randomized to the control group (Group II) received only
dressing.

Preparation of PDGF:

After informed consent was obtained, 60 ml of
blood was drawn into a syringe containing 5 ml of the
anticoagulant citrate dextrose. This blood was centrifuged (140 g
for 20 minutes at 4° C) to remove red and white blood cells, leaving a
platelet-rich plasma. Platelets were removed from the plasma by
further centrifugation (800 g for 10 minutes at 4° C), and were then
re-suspended in normal saline solution at a concentration of 10⁹
platelets/ml. The platelets were then treated with 1
unit/ml thrombin (T-4648; Sigma, St. Louis, Mo.) to create a
supernatant that contained the released PDGF. The PDGF-containing
suspension was then added to 1 gm of collagen (C-9879; Sigma) to
produce a sterile topical salve. Each 10 ml salve, according to
the size of ulcer, was used for 5-7 days and then discarded.

Procedure:

At the first visit of each patient a complete
history was taken and a physical examination was performed, and
the ulcer area and depth and presence of infection and necrosis
was noted. Initial paraclinical work-up consisted of hemoglobin,
leukocyte and platelet count, BUN and Cr measurement and blood
cultures. If an ulcer was infected, it was treated with
antibiotics, and when infection was eradicated it was included in
the study. At the initial clinical visit, if indicated, the
wounds were sharply debrided of all necrotic tissue.

Wound care protocol:

Patients used a once-daily wound dressing
protocol described as follows:

Treatment group (PDGF+ dressing):

Each ulcer which was free of infection and
necrosis was thoroughly washed with isotonic normal
saline solution and then a thin layer of PDGF was applied
to the ulcer’s entire surface. One hour later the ulcer
was covered with a paraffin-impregnated gauze and a
sterile gauze dressing and left in place for 24 hours.
These applications were continued for two weeks, or
sooner if complete epithelialization of the wound
occurred.

Control group (sterile dressing):

Ulcers in this group were washed thoroughly with
isotonic saline solution and after one hour they were covered only with
paraffin-impregnated and sterile gauze dressing for the next 24 hours. Each
patient in the control and treatment group was evaluated every three days for
evidence of wound healing.

Standard patient care control:

All patients in the treatment and control
groups, received supportive traditional wound care
throughout the trial, including change in position, use
of water-filled pillows and diluted betadine solution to
the skin around the ulcer.

Statistical analysis:

For comparison of data between the two groups,
student t-test was used. Kolmogorov-Smirnov goodness of fit test
(K-S) which was a pre-requisite for t-test was applied. For
comparison of mean values of the dependant parameters, such as
renal failure and sepsis (evaluation of effect of renal failure
and sepsis on wound healing), analysis of variance was applied.
Fisher exact test was used to compare the percentage of healing
in treatment and control groups.

Results

Fifteen patients with twenty decubitus ulcers
were randomized to treatment and control groups. Initial patient
data in each group are shown in Table 1.

As shown, there is no statistically significant
change between the age of patients, platelet number, duration of
therapy and initial area and depth of ulcers in the two groups.

Wound healing rates were determined and the
results are shown in Table 2. At the end of the
study, four patients in the treatment group had complete wound
healing and a considerable reduction in ulcer size occurred in
the rest. In this group, the mean wound area reduction compared
to this change in the control group was 3.90±2.42 and
–1.44±2.24 cm² respectively (p=0.001). The
change in ulcer depth in the treatment group compared to the same
change in the control group was 3.45±2.54 and –2.22±3.76
mm³ respectively (p=0.001). A seventy percent
reduction in wound area in the treatment group was 70.80±29.81%
and the corresponding change in the control group was
–29.53±49,29% (p=0.001). The reduction in the depth of
ulcer to about seventy percent of initial depth in the treatment
group versus the control group was 70.83±30.56% and
–47.68±72.68% respectively (p=0.001).

In the control group only one patient showed a
reduction in ulcer size and the rest had either no change or an
increase in their ulcer size was observed. Four patients in the
treatment group had renal failure and wound healing was observed
in all of these. Two patients with renal failure having two
similar decubitus ulcers and who were treated with simple
dressing failed to show ulcer healing. Four patients with sepsis
in the treatment group had wound healing, while ulcers in septic
patients belonging to the control group did not heal.

Discussion

Recent advances in the biology of wound healing
demonstrate that macrophages and platelets are predominant
regulatory cells in the repair process. Platelets are known to
release certain factors from alpha granules, four of which have
been identified. These are the platelet-derived angiogenesis
factor, which causes new capillary formation from the existing
micro-vasculature¹²; platelet-derived growth factor
(PDGF), which is a potent fibroblast mitogen and chemoattractant^13-15;
platelet-derived epidermal growth factor; and platelet factor 4,
considered to be a chemoattractant for neutrophils ^14,16.
PDGF was initially isolated from platelets but subsequently found
to be synthesized by a variety of normal and malignant cells. It
is the product of two genes, PDGF-A and B, which are the source
of two distinct PDGF-A and B chains. These two chains can combine
to form dimers of PDGF-AA, BB and AB. PDGF-BB is more effective
than others. Recently recombinant PDGF-BB (rPDGF-BB) has been
successfully used in the management of various ulcers, including
decubitus ulcer¹⁷. In 1986, Knighton et al. showed
that the use of autologous platelet factors, by accentuating the
formation and epithelialization of granulation tissue, lead to
the complete healing of ulcers¹⁸. In 1990, Atri et al.
confirmed that recalcitrant skin ulcers can be stimulated by
homologous PDGF to produce reparative cellular response¹⁹.
In this study we used autologous PDGF to promote wound healing in
a group of patients with decubitus ulcer. Complete healing
occurred in 36% of patients in the treatment group, while in the
others a remarkable reduction in the size of ulcers was detected
during two weeks of therapy. In the control group, complete
healing did not occur in any ulcer, but a reduction in the size
of ulcer was detected in 12.5% of patients. So we conclude that
topically-applied autologous-PDGF promotes wound healing in
patients with decubitus ulcer. Renal failure and sepsis did not
adversely influence the wound healing process in treated
patients.

References

1 Meijer JH. Susceptibility to decubitus
ulcer formation. Arch Phys Med Rehabil 1994; 75:318-25

2 Leigh IH. Pressure ulcers: Prevalence,
etiology, and treatment modalities. Am J Surg 1994; 167:25S-30S

3 Kosiak M. Etiology and pathology of
ischemic ulceration. Arch Phys Med Rehabil 1959; 40:62

4 Fisher SV, Szymke TE, Apte S, Yand
Koziak M. Wheelchair cushion effect on skin temperature. Arch
Phys Med Rehabil 1978; 59:68-72

5 Bergstrom N, Braden BA. Prospective
study of pressure sore risk among institutionalized elderly. J
Am Geriatr Soc 1992; 40:747-58

6 Dietrick JE. Effect of immobilization
on metabolic and physiological function of normal men. Bull NY
Acad Med 1958; 24:364-75

7 Yorkony GM. Pressure ulcer. Arch
Phys Med Rehabil 1994; 75:908-17

8 Vaziri ND, Eltorai I, Gonzales E, et
al. Pressure ulcer, fibronectin, and related proteins in spinal
cord injured patients. Arch Phys Med Rehabil 1992; 73:803-6

9 Dinsdale SM. Decubitus ulcer in swine.
Light microscopic study of pathogenesis. Arch Phys Med Rehabil
1973; 54:51-56

10 Ernesto C. Clinical review 35: Growth
factors and their potential clinical value. J Clin Endocrinol
Metabol 1992; 75:1-4

11 Lynch SE, Colvin RB, Antoniades HN.
Growth factors in wound healing: Single and synergistic effect on
partial thickness porcine skin wound. J Clin Invest 1989;
84:640-6

12 Knighton DR, Hunt TK, Thakral KK,
Goodson WH. Role of platelets and fibrin in the healing sequence:
An in vitro study of angiogenesis and collagen synthesis. Ann
Surg 1982; 196:379-88

13 Ross R, Glomset J, Kariya B, Harker
L. A platelet-dependant serum factor that stimulates the
proliferation of arterial smooth muscle cells in vitro. Proc
Natl Acad Sci USA. 1974; 71:1207-10

14 Antonaides HN, Scher CD, Stiles CD.
Purification of human platelet derived growth factor. Proc
Natl Acad Sci USA 1979; 76:1809-13

15 Gerotendorst GR, Martin GR, Pencer K,
et al. Stimulation of granulation tissue formation by
platelet-derived growth factor in normal and diabetic rats. J
Clin Invest 1985; 76:2323-9

16 Deuel TF, Senior RM, Huang JS,
Griffin GL. Chemotaxis of monocytes and neutrophils to
platelet-derived growth factor. J Clin Invest 1982; 69:1046-9

17 Rabson C. Martin GR. Platelet-derived
growth factor-BB for the treatment of chronic pressure ulcer. Lancet
1992; 339:23-25

18 Knighton DR, Ciresi KF, Fiegel VD, et
al. Classification and treatment of chronic non-healing wounds:
Successful treatment with autologous platelet-derived wound
healing factors (PDWHF). Ann Surg 1986; 204: 322-30

19 Atri SC, Misra J, Bisht D, Misra K.
Use of homologous platelet factors in achieving total healing of
recalcitrant skin ulcers. Surg 1990; 108 (3):508-12