Application of Allogeneic Fibroblasts in the Complex Treatment of Gunshot Wounds

The dissertation is dedicated to the development and implementation of a methodology for the complex treatment of soft tissue gunshot wounds using allogeneic fibroblasts in the form of a dermal equivalent. The mechanisms of action of allogeneic dermal fibroblasts on the wound healing process are studied, the clinical effectiveness of this approach is evaluated compared to traditional treatment methods and the application of the biodegradable collagen wound covering «Collost», and the histological and cytological features of wound healing when using a dermal equivalent are investigated. The results can be used by surgeons in hospital conditions when a cell culture bank is available or in close proximity to a biotechnology center.

Relevance of the topic

Since the second half of the nineteenth century and to the present day, our country has been continuously participating in both global and local armed conflicts, in which firearms play a leading role. In the structure of combat surgical trauma, gunshot wounds currently constitute the major portion (up to 65%): both bullet wounds caused by the impact of modern high-velocity penetrating projectiles on the body and fragmentary wounds as a component of mine-explosive injury. [57,45,61,90].

The mechanism of gunshot wound formation and the severity of the victim's condition determine the specifics of the wound healing process, which manifests in the prolongation of all its phases. Severe damage leads to the development of traumatic illness, with the incidence of wound infection ranging from 40% to 70%. All of this are the causes of the formation of extensive and long-term non-healing wounds, the treatment of which is an urgent problem [59, 81].

The modern system of medical evacuation measures in the medical service of the Armed Forces of the Russian Federation allows for the delivery of the wounded to the stage of specialized surgical care in the shortest possible time, where they receive comprehensive treatment with the application of the most modern scientific developments introduced into clinical practice [40, 62, 88, 115]. The main principles of providing surgical care to patients with gunshot wounds include performing primary surgical debridement and subsequent, earliest possible wound closure [5, 13, 23, 31, 38, 42, 54, 80, 110]. The arsenal of means used in the treatment of extensive gunshot wounds during the second and third phases of the wound healing process is sufficiently broad; however, the results do not fully satisfy surgeons: long-term non-healing wounds and coarse scars impairing the functions of extremities and organs are frequently formed [64, 79, 92, 119].

A new direction in local wound treatment — the use of auto- and allogeneic cultured skin cells (keratinocytes and fibroblasts) obtained by biotechnology. At present, cultured in vitro skin cells are used for the treatment of burns. In recent years, there have been reports of their successful use in the treatment of trophic ulcers and long-term non-healing wounds [95, 101, 112, 151, 163].

If the application of multilayer autograft keratinocyte sheets is conditioned by the possibility of forming an epidermis, then the mechanism of action of allogeneic cells is not yet fully understood. However, their successful use for closing burns, donor wounds, and trophic ulcers allows us to suggest that allogeneic keratinocytes are temporarily incorporated into the forming epidermis, stimulate epithelization by secreting biologically active substances and growth factors, and are subsequently replaced by the patient's own keratinocytes. Negative factors of keratinocyte use include the duration of cultivation (about 20 days), increased sensitivity to traumatic factors, and high cost. The principle of applying allogeneic fibroblasts is based on their direct influence on wound healing and epithelization. Fibroblasts can produce type I and III collagens and extracellular matrix components: laminin, nidogen, tenascin, chondroitin-4-sulfate proteoglycan, fibronectin; certain growth factors stimulating collagen adhesion and keratinocyte migration. Culturing fibroblasts in vitro is technically simpler, faster (cultivation periods of 2–8 days), and less expensive compared to keratinocytes [91, 124, 126; 138].

Information on the use of cultured in vitro fibroblasts in the treatment of gunshot wounds is absent from available literature, yet the specifics of gunshot wound formation and healing compel researchers to seek new approaches to treating these wounds.

Objective of the work: improving treatment outcomes for patients through the development and implementation of a methodology for treating soft tissue gunshot wounds using allogeneic fibroblasts in the form of a dermal equivalent (DE).

Research tasks:

1. To study the influence of allogeneic fibroblasts in the form of DE on the course of the wound healing process in a gunshot wound, as well as to assess its ability to stimulate reparative processes.

2. To evaluate and analyze the clinical effectiveness of using DE in the complex treatment of a gunshot wound compared to traditional treatment methods and the application of the biodegradable collagen wound covering «Collost».

3. To study the possibilities of using allogeneic fibroblasts to reduce complications such as the formation of long-term non-healing wounds, trophic ulcers, and coarse scars impairing the functions of extremities and organs.

Scientific novelty

In the dissertation, the mechanisms of action of allogeneic dermal fibroblasts in the form of DE on the course of the wound healing process in a gunshot wound are studied. The influence of DE on reparative processes during the second and third phases of the wound healing process is investigated. Research on the effectiveness of treating gunshot wounds using allogeneic fibroblasts compared to traditional methods of local treatment and the application of the biodegradable collagen wound covering «Collost» has been conducted. The histological and cytological picture of gunshot wound healing when using DE has been studied.

Practical significance

The results of the research can be used by surgeons in hospital conditions when a cell culture bank is available or in close proximity to a biotechnology center. The application of this method allows for reducing the duration of patient treatment by accelerating the healing of gunshot wounds, as well as preventing the development of complications such as the formation of long-term non-healing wounds, trophic ulcers, and hypertrophic scars impairing the functions of extremities and organs.

Implementation of research results

The proposed methodology for treating gunshot wounds using allogeneic dermal fibroblasts has been implemented and is used in the clinical activities of surgical departments of the N.N. Burdenko Military Clinical Hospital and in pedagogical activities of the Department of Surgery at the State Institute for Advanced Training of Physicians of the Ministry of Defense of the Russian Federation.

Dissertation defense

The materials and results of the dissertation research were discussed at a meeting of the Department of Surgery at the State Institute for Advanced Training of Physicians of the Ministry of Defense of the Russian Federation.

Publications

Seven printed works have been published on the topic of the dissertation research, one of which is in the central press.

Basic provisions of the dissertation submitted for defense

1. Allogeneic dermal fibroblasts in the form of DE reduce the healing time of gunshot wounds by accelerating the course of the second and third phases of the wound healing process.

2. DE is effective in the complex treatment of gunshot wounds; its application allows for increasing the proportion of patients with spontaneous wound closure without the need for operative plastic closure procedures, as well as preparing the wound for plastic surgical operations at earlier stages.

3. The application of DE allows for reducing the number of complications such as the formation of long-term non-healing wounds and coarse hypertrophic scars impairing the functions of extremities and organs.

Volume and structure of the dissertation

The dissertation is presented in 108 pages of typed text and consists of an introduction, three chapters (literature review, description of materials and research methods, and original results with discussion), conclusion, summaries, practical recommendations, and a bibliography list of 181 sources (120 domestic and 61 foreign authors). The work is illustrated with 10 tables and 16 figures.