Skin Bank & Laboratory

Skin Bank & Laboratory
The Trauma Burn Resource Center functions as a support facility for the Trauma Burn Center. Services are provided in areas of Microbiology, Banking of Skin and Skin Substitutes, Infection Surveillance, Environmental Monitoring, and participation in Clinical Research Trials/ Investigations.

LOCATION

The Trauma Burn Resource Center is a modern well equipped, 1400 square foot facility located within Trauma Burn Center on the 1st floor of the University Hospital (room 1C-435).

SERVICES

  • Microbiology
    • Perform quantitative wound biopsy cultures
    • Perform rapid slide determinations for predicting microbial growth
    • Perform topical anti-microbial sensitivity testing
  • Banking
    • Banking of cadaveric allograft skin for grafting purposes
    • Banking of patient autograft skin for subsequent grafting
    • Banking of skin substitutes and artificial skin for patient use
  • Infection Surveillance
    • Monitor Trauma Burn Center patient microbiology cultures
    • Attend and participate in Trauma Burn Center wound rounds
    • Work collaboratively with Infection Control Service to resolve Trauma Burn Center infection control problems
  • Environmental Monitoring
    • Microbial monitoring of equipment, rooms, water, etc. as needed
  • Clinical Trials/Investigations
    • Assist in clinical research protocols

ANATOMY OF SKIN

Anatomy of Skin
Skin is often considered the largest organ system of the human body. The average adult male has 18 square feet of skin weighing over 6 pounds. Skin is a remarkably durable structure with an incredible ability to regenerate and heal itself. Skin is comprised of two layers, the epidermis and dermis.

The epidermis is the outermost layer containing keratinocytes and melanocytes. Keratinocytes contain keratin, a protein, which provides a durable mechanical and moisture barrier to protect underlying tissues. Melanocytes are pigment (color) producing cells and are responsible for skin color. The epidermis is continually regenerating itself. New cells are constantly being made as the outer layers die and are worn away. Although the epidermis is the outermost layer of the skin, epidermal cells also line the oil and sweat glands as well as the hair follicles.

The dermis is the innermost layer of the skin and consists of collagen, a structural protein, which is produced by fibroblast cells. The dermis is extremely durable and flexible. Within the dermis are blood vessels, hair follicles, oil and sweat glands, and nerve endings.

The skin provides the following functions for the human body:

  1. Provides a physical barrier to the outside environment.
  2. Provides outward appearance.
  3. Conserves body fluid by preventing evaporative loss.
  4. Provides thermo-regulation/maintains body temperature.
  5. Excretes water and oils.
  6. Produces vitamin D in the presence of sunlight.
  7. Provides sensations of temperature and touch.
  8. Assists in the development of the immune system.

SKIN INJURIES

Skin Injuries
The most common injury to the skin is burns. An estimated 130,000 individuals are hospitalized annually in the United States due to burn injuries. Many burns are small and will heal completely on their own if kept free from infection. Many different rating scales for burn injury exist, however, the most common are: 1st, 2nd, and 3rd degree burns.

First (1st) degree burns are superficial burns and can be quite painful but are generally not considered life threatening. An example would be a sunburn. First degree burns involve only the epidermis.

Second (2nd) degree burns or partial thickness burns are more severe and will involve the epidermis and the dermis. The healing of 2nd degree burns is dependent on how deeply the dermis is burned. If the epidermal cells that are found surrounding the hair follicles and skin glands are not damaged, then they will regenerate and grow a new epithelial (skin) covering. If the dermis is burned deeply enough to destroy its internal structures, then new epithelium will not regenerate and grafting may be required.

Third (3rd) degree burns or full thickness burns destroy both the epidermis and dermis and may affect deeper tissues such as fat and muscle and connect tissues. Most 3rd degree burns will need grafting to replace the lost dermis and epidermis.

Other injuries to the skin which require grafting can be caused by trauma, abrasions, frostbite, infection, ulcers, and auto-immune diseases.

SKIN BANKING

Skin Banking
Skin Banking is a process in which skin is removed from a donor body, tested for suitability as a graft material, packaged, stored, and finally reused as a graft. The process is similar to that for blood banking. Skin grafts can be autografts or allografts.

An autograft is tissue which is removed from and then used on the same individual. Auto-skin grafts can be used as a treatment for 2nd and 3rd degree burns and for reconstructive surgery. Skin autografts are permanent replacement grafts and will heal full thickness burn wounds. Autografting requires that skin be removed from a "donor site". Autografts involve the removal the epidermis and some of the dermis but are not deep enough to remove the hair follicles and glands. Therefore, the epidermal cells within the hair follicles and glands can regenerate (grow) a new epidermis over the donor site while the skin graft provides a new epidermis and some dermis to the wound it covers. Because autografts are thin and usually don't contain hair follicles or glands, the grafted areas will be devoid of hair and unable to sweat.

Allografts are tissue that is removed from one individual and used on a different individual. Allograft skin is used as a temporary burn wound graft and will be rejected by the recipient, usually within 7-21 days. Until rejection, however, allograft skin will provide many of the functions of healthy skin. Skin allografts will close a wound providing a barrier against infection and fluid loss, decrease pain, and promote healing of underlying tissues. Skin allografts are use as a transitional treatment until autografting can permanently close the burn wound. Allograft skin is obtained from cadaveric (deceased) donors after consent is obtained from the next-of-kin. Tissue donors are carefully screened by reviewing past and present medical records, interviewing medical staff, interviewing the next-of-kin for past medical history and high risk lifestyles. Samples of the donor's blood are also tested for many transmissible diseases including hepatitis and AIDS.

Allograft skin may be used fresh or frozen. Fresh skin allografts are considered by some to be more desirable because they are more viable (alive) than frozen grafts. Others feel that viability is unimportant because the grafts are only temporary. Fresh skin grafts are maintained in a fluid medium intended to keep the cells alive and nourished. Fresh storage will only maintain skin grafts for approximately 14 days. It may take upwards of 10 days to release tissue from quarantine due to bacterial and serologic testing therefore, most skin banks freeze their tissue grafts. Freezing skin grafts involves soaking the tissue in special medium (cryoprotectants) and then freezing the tissue grafts in a controlled environment. Cryoprotectants are intended to minimize the freezing injury to cells. Most tissues are control-rate frozen at 1-5 degrees Centigrade per minute and then stored at ultra-low temperatures (below -60 C). Frozen grafts can have a shelf life of up to five years.

SKIN DONATION FAQ

Skin Donation FAQ
How can I learn about tissue donation?
An excellent resource to learn all about organ and tissue donation is from an Internet site called: http://www.Transweb.org/.

I recently lost a great deal of weight and I have a lots of excess skin. Can I donate my excess skin to a skin bank to help burn patients? Will a tissue bank pay for my skin reduction surgery if I agree to donate my tissue?
These questions are asked quite often by individuals who have lost large amounts of weight and have excess skin folds. We appreciate your desire to donate, however, this kind of donation is unworkable. Allow me to explain why: 

 

Our center does not obtain skin from these patients for several reasons. First, this method of obtaining skin is cost prohibitive. The amount of transplantable tissue obtained from tissue reduction surgery is minimal when compared to the amount of tissue obtained from a cadaveric (deceased) tissue donor. The procurement costs would be much greater as it would require the services of doctors, nurses, anesthetists, and other health care professionals as well as the use of an operating room and other hospital services. Cadaveric donation requires only trained tissue recovery technicians, and they can procure tissue after the body has been sent to the morgue (rather than in an operating room), thus keeping expenses to a minimum.

Additionally, cadaveric donated tissue can be used for transplant soon after recovery (as soon as quality assurance testing is complete), however, the FDA requires that tissues recovered from living donors must be placed into quarantine for six months. At the end of six months, all serologic testing (HIV and Hepatitis) of the donor must be repeated before that tissue can be used.

It is extremely difficult to obtain a skin graft from tissue than has been removed during tissue reduction surgery. The usual procedure for tissue reduction surgery involves the removal of skin and underlying attached tissues, often several centimeters. Skin grafts used for transplant (burn patients) are only 15/1000 (0.015) of an inch thick and do not include these underlying tissues. Skin grafts for transplant are obtained by the use of a surgical device called a dermatome, which peels off a very thin (0.015 inch) uniform layer of skin.

I do not know of any tissue bank that would pay for a donor's tissue reduction surgical expenses for the purpose of obtaining skin for transplantation. If you are interested in donating your tissues upon your death I would encourage you to share this information with your family. Your gift can save lives and greatly reduce suffering.

Can I donate a small piece of skin in exchange for money?
No. Our center does not obtain tissues from paid donors. In fact, the American Association of Tissue Banks (AATB) and Federal regulations prohibit monetary inducement for donation.