The Use of Acellular Fish Skins as Xenografts

ABSTRACT

Every year, numerous people suffer and often succumb to the extreme pains of burn injuries. In the United States alone, approximately 450,000 individuals suffer burn injuries annually – some so severe that they require treatment in a Medical Burn Unit. Nearly. 3500 are victims of life-threatening burns that are caused due to accidents and fires. A revolutionary method for treating burns involves the use of acellular fish skin as xenografts. This treatment can be used not only for burn wounds but also for the treatment of diabetic ulcers, combat wounds, etc., thus opening doors of possibility in the field of medicine.

BACKGROUND

The use of fish skin as a biological dressing was primarily studied and researched in Brazil. Tilapia skin is a type of fish skin that has a structure similar to that of human skin, due to which it can be used as an ‘acellular scaffold’. Samples of Nile Tilapia Fish Skin (NTFS) from farm fish were collected by the Colony Forming Unit and studied. It was found that non-infectious microbiota and collagen were present in the fish skin. Compared to human skin, the amount of Type-1 collagen and moisture in NTFS was higher, enabling it to ensure minimal scarring in the healing processes of second and third degree-wounds. It also gives the Tilapia skin characteristics such as excellent biocompatibility, low immunogenicity and

anti-inflammatory properties, all of which promote fast healing of injured areas (re-epithelization). It is also antibacterial and antiviral, as it contains Omega-3-fatty acids. A typical treatment involves the use of antibiotics through creams and/or intravenous (IV), due to the risk of an infection at the wound site. Furthermore, the use of fish skin as a treatment is cheaper when compared to the traditional alternatives. When compared to sulfadiazine creams, its cost is nearly 75% less, hence making it a financially viable option.

NTFS also has high tensile strength, which, in comparison to alternatives such as pigskin, makes it superior in terms of flexibility and suitable for ensuring comfortability and adaptability for the patient. It soothes pain, reduces the healing times by days and, like all skin substitutes used for the treatment of superficial burns, it also reduces the frequent need to replace the dressing.

METHOD AND MATERIAL

Fish skin Collection: Tilapia skin is easily accessible due to the widespread nature of fish farming. It is available in abundant quantities.

Sterilization: The skin must be sterilized to get rid of any germs present on it, as well as its pungent smell8. There are various options for sterilizing agents that can be used for this step. A study conducted compared three sterilizing agents- chlorhexidine gluconate 4% (CHG), povidone-iodine 10% (PVP-I) and silver nanoparticles (AgNPs) (25 μg/mL). It was found that silver nanoparticles are the most effective for the sterilization of Tilapia skin, with an efficiency of 100%, against microbial growth and without any change in the collagen content of the skin. The overall process of sterilization involves the use of chemicals, followed by steps including glycerolizing and irradiation9.

Testing: The sterilized skin must be tested for microorganisms such as bacteria and fungi that pose a risk of infection. It can then be stored in refrigerated sterile packaging.

Cleaning: The lesion must be cleaned, like any other superficial burn wound. Following that, it is important to remove any necrotic and fibrinous tissue from the lesion to allow maximum contact between the NTFS and the wound bed, for more effective results.

Rehydration: The cleaned skin is then rehydrated by washing it in a saline solution of concentration 0.9% for 5 minutes, 3 times in a row. This ensures that its natural consistency is retained post the chemical sterilization10.

Application: Coverage of at least 1cm of healthy skin in the borders of the wound and superposition of at least 1cm between NTFS pieces are needed, so that movement in the initial stages of treatment will not lead to exposing any area of the burn. The Tilapia skin must be applied directly, and firmly held in place using gauze and bandages. Once new skin forms, the fish skin covering will start to come off. To remove it, it can be hydrated by soaking in water, which will make it break and slip off, revealing the healed site underneath.

CASE STUDY

Apart from its use on humans, this treatment is also used in the veterinary field for cases where Tilapia skin was used for healing bite wounds on a dog and burn injuries on bears and mountain lion cubs.

This particular case is one of a 23-year-old male in Brazil, suffering from burn wounds on his arm due to contact with flames from a gunpowder explosion. The patient’s injuries after the cleaning of the lesion are shown on the left14. The condition of his burns is described as so:

“Superficial partial thickness burns (SPTB) were present in the right upper limb and deep partial thickness burns (DPTB) were present in the left upper limb, face and anterior and posterior thorax.” The entire process of application of Tilapia skin was performed, following which the patient’s wound had a significant recovery. The images on the right show the condition of the arm upon application of the graft and on the 17th day of the treatment.

CONCLUSION

Due to their numerous advantages as compared to alternative treatments, the use of acellular fish skin grafts such as Tilapia skin promises a new direction in the treatment of superficial burn wounds. Their effectiveness, low cost, accelerated healing time, reduced need to change the dressing and long-term viability make them a superior choice for such treatments.

However, more studies on larger scales are important to explore the potential of this method in the medical field.

CITATIONS

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