CAUSES OF HYPERTROPHIC SCARS IN CHILDREN WITH

EFFECTS OF BURNS

AND WAYS TO PREVENT THEIR DEVELOPMENT

Filippova O.V., Baindurashvili А.G.,Krasnogorskiy I.N., Afonichev К.А. FSBI «Scientific and Research Institute for Children’s Orthopedics n.a.

G.I.Turner»

under the Ministry of Health of the Russian Federation

Saint-Petersburg

Significance:

extensive planar scarring is not

always possible to remove

completely with surgery;

obvious clinical presentation

that causes considerable

discomfort in the child

indicates the need for

systematizing of conservative

treatment based on

morphological features of

scarring at each stage of their

maturation;

prolonged excessive activity of

scarring process impairs

functional and aesthetic

outlook and the possibility of

reconstructive surgery in the

future.

Objective: to identify the

leading mechanisms of

hypertrophy of postburn scars

at different stages of their

maturation, to develope

regimen of conservative

treatment.

Clinical material and methods

Patients: 217 children aged from 4 to 15 y/o, with extensive scarring requiring multistage reconstructive treatment

Methods:

Clinical: assessment of anamnesis, complaints, external characteristics of scarring

Histological method: evaluation of morphometric parameters of scar layers and microvascular bed, cells, and their number

Immunohistochemical method:

~ detection enzymes of mast cells, which play an important role in the development of inflammation and remodeling of connective tissue matrix (Mast cell Tryptase);

~ detection of identifier of macrophagal activity CD 68;

~ detection of markers of cellular apoptosis - p53 and its inhibitor - Protein bcl-2

Histological and immunohistochemical studies were

performed using the equipment:

~ preparation of slices: Microm STP 120, Microm EC350, Microm

HM 430 (Carl Zeiss, Thermo Scientific, Germany);

~ microscopic examination of histological preparations and photographs were taken using a light microscope Axio Scope А1 (Carl Zeiss, Germany);

~ morphometric measurements were carried out in the studied tissues using light microscopy Leitz (Wetzlar, Germany);

~ the study of processes in the scar tissue was performed with monoclonal antibodies to various antigens Novocastra, Leica Microsystems (United Kingdom), Sigma-Aldrich (Israel)

Lymphocytes, macrophages and mast cells are a source of

fibrogenic cytokines. Excessive activity of lymphocytes,

macrophages (CD 68) and mast cells (Mast cell Tryptase)

enhances fibrosis and scar hyperplasia

0

500

1000

1500

2000

2500

1-6

mon.

7-12

mon.

1-2 y. 2-6 y.

Intact skin

Scar

Number of

lymphocytes

at 1 мм2

Lymphocytic infiltration

in the scar Intact skin

0

20

40

60

80

100

120

140

160

180

200

1-6

months

1-2 y.

Intact skin

Scar

0

50

100

150

200

250

300

1-6 m. 7-12 m. 1-2 y. 2-5 y.

Intact skin

Scar

+ CD 68

at 1 мм2

+ Mast cell Tryptase

at 1 мм2

Increased activity of

macrophages CD 68 is

observed for a further year

after epithelialization

of burn wound

During the first 6 months

after the burn wound

epithelialization, enzyme

(Mast cell Tryptase) increase

is noted, indicating the

activity of mast cells.

(hematoxylin-eosin, × 300)

Prolonged macrophage-lymphocyte activity in the

scar creates a cytokine pattern that contributes to

disorder of cell apoptosis and long synthetic activity

of fibroblasts

4 - 12 months after epithelialization: strong decrease in the ability of cells to apoptosis p53, accompanied by increased apoptosis inhibitor bcl-2 in the first half-year.

12 months - 2 years: the maximum level of cell apoptosis, the minimum values of the inhibitor apoptosis..

2 - 5 years: normalization of inhibitor of apoptosis. The ability of cells to apoptosis in mature scars remained low.

050

100150200250300350400450

4-6

mon

ths

7-12

m.

1-2

y.

2-5

y.

+р53

+bcl-2

+р53 intactskin

+bcl-2 intactskin

number of

cells

at 1 мм2 р53 -marker of apoptosis

bcl-2 -inhibitor of apoptosis

time from the moment the wound epithelialization

Dynamics of expression of apoptosis inhibitor

bcl-2 in different periods after epithelialization

After 4 months After 8 months After 1.5 years After 3 yaers Intact skin

(magnification x 300)

*

*

*

* *- p<0,05

scar in 3-4 months after

epithelialization:

multiple expansion due

to compression of the

lumen of venules, their

collagen bundles at the

mesh layer, impaired

venous drainage

scar in 5-12

months

after

epithelialization:

reducing the lumen

of arterioles and

venules due to the

ongoing synthesis

of collagen

scar in 2 years

after

epithelialization:

uniform

vasoconstriction

scar in 2 years after

epithelialization:

trophic erosion of

functionally active

areas on the

background of

worsening

circulatory

Excessive collagen synthesis leads to an irreversible

change in the conditions of circulation in scar

(hematoxylin-eosin, × 300)

Conclusions

In the first 4-6

months after

epithelialization:

increased activity of

lymphocytes and

macrophages,

cytokine synthesis

and stimulation of

fibroblasts

From 5-6 months

after

epithelialization -

compression of

venules with

collagen bundles,

impaired venous

drainage

From 8 months to

1, 5 years -

compression of

arterioles with

collagen bundles,

impaired arterial

inflow

Uniform narrowing

of the vascular bed

The most significant prognostic period is a period of scar development from 1 to 6 months:

adequate conservative therapy in this period can significantly improve the functional and cosmetic

characteristics of the scar

Cytokine

phase

of scar

development

Collagen-

venous phase

of scar

development

Collagen-

arterial phase

of scar

development

Аdaptation phase

compression,

antihistamine

and anti-

inflammatory

therapy

compression,

collagenolytic,

antihistaminic

therapy

compression,

collagenolytic,

antihistaminic

therapy,

silicone

preparations

collagenolytic

therapy,

silicone

preparations,

polishing