Title: Can Therapeutic Ultrasound Influence the Integration of Skin Grafts
Author: Adriana da Costa Goncalves
Source: Ultrasound in Medicine and Biology Sep2007, Vol. 33 Issue 9 p1406-1412
Autogenous skin grafting is the most common skin graft procedure used. It can be implemented in a wide variety of circumstances from burns to reconstruction. The skin grafts usually heal on their own, except for in cases when tissue necrosis and eventual rejection of the entire graft occurs. In this case the area must be grafted again or another plan of action must be attempted. Since therapeutic ultrasound has been shown to effectively heal and regenerate skin, bone, muscle, tendon, and peripheral nerve tissue scientists are trying to explore if it can be used in accelerating skin graft integration.
The use of ultrasound in skin graft integration was done in a trial consisting of twenty female New Zealand rabbits. The rabbits received a skin graft in the dorsal region. The graft was covered over with a tie-over Brown type dressing for three days which was then removed to allow therapeutic ultrasound. In some cases the therapeutic ultrasound was done over the entire graft. In others the graft was divided into two parts, one that received the ultrasound (group 1) and one that only received the manual massage of the ultrasound head but not the actual ultrasound (group 2). After eleven days the animals were killed and the skin grafts were removed for study.
Results showed that there was no significant difference between the epidermal and dermal area between group 1 and 2 after eleven days. However it was observed that there was a significant increase in proliferating cells in group 1 at 12.18% compared to the 7.34% of group 2. It also showed that there was a significant amount of new blood vessels in the reticular layer of the dermis in group 1 compared to that of group 2. It was also observed that after 35 days there was no visible difference between group 1 and group 2.
The biological mechanism of ultrasound in the integration of skin grafts is still not entirely clear. However, the increase in proliferating cells and new blood vessels points to better integration. Yet, like in all animal testing the difference in rabbit and human skin must be taken into account. The results in the rabbit trials do suggest that human trials should take place.
If ultrasound proves to be effective in humans it could be very important to skin graft surgery. It could be used in graft rejection, since we still don’t really know why autologous grafts are rejected in the first place. It could solve the problem of having to regraft or not being able to graft on a particular person. Also, if it can help in integration, it could speed up recovery time, allowing patients to get out of the hospital and back to normal life faster, and ultimately cutting down on costs.
Monday, November 19, 2007
Sunday, November 18, 2007
Discovery on Manipulating Skin Tone
Title: Discovery On Manipulating Skin Tone
Date of Publication: August 26, 2007
Found in: Medical Research News
Scientists from the University of Cincinnati and Tokyo Medical University have been searching for ways to make human skin look healthier and younger by manipulating skin tone and color. While your mind may jump right to Michael Jackson’s horrendously bleached skin, the researchers are not looking for ways to improve skin bleach. They are looking to bioengineered skin grafts as a way to even out the colors and tones of skin that is either discolored or has patches of discoloration.
Part of the function of these bioengineered skin grafts is to help cosmetic companies develop new products so that people can achieve the perfect sunless tan. These skin grafts are not meant for people who wish to completely change the color of their skin, although this is a concern that must be addressed sooner than later. If this is not addressed, it is possible that people with light-colored skin who wish to be darker and people with dark-colored skin who wish to be lighter will subject themselves to whole body skin grafts to achieve a complete change in skin color. This would exponentially increase racial tensions nationwide, and possibly worldwide. However, once this kind of scientific advancement is made, it is quite a challenge to keep it out of the hands of the wrong people. This dilemma is similar to the debate about screening embryos for genetic predispositions to develop certain inherited diseases. While that is generally seen as positive, some people are against it because they believe that screening embryos will lead to the age of designer babies, which is seen by many as unethical. The line is just as fine for this research study: why is it socially acceptable to have skin darkened so that it is tanner, but not socially acceptable to have skin lightened? It seems as if making your skin darker is not perceived as wanting to change your racial identity, while making your skin lighter is.
The research study was published in the September issue of the Federation of American Societies for Experimental Biology journal (FASEB), and explained how, for the first time, scientists were able to manipulate skin color and tone by using cells that were previously thought to play no significant role in skin tone and color.
Researchers describe how the cells responsible for pigmentation, melanocytes, can be controlled by keratinocytes, the most commonly occurring skin cells. Keratinocytes make up 90% of epidermal cells (the cells on the outermost layer of the skin) and do not produce any pigment of their own. Working with bioengineered skin that is usually used for skin grafts to help burn victims recover posed a couple of difficulties for the researchers because they had to balance various mixtures of keratinocytes from people with vastly different types of skin colors and tones. The keratinocytes were found to produce chemical signals that tell the melanocytes to produce more or less pigment, called melanin, as well as how to distribute the pigment that they produced. Distribution is really important because it insures that the skin has even tones and colors and that there are not any patches of skin that are radically different colors from the rest of the skin on a person.
It has been known for a while that the more melanin produced, the darker the skin tone is, and conversely, the less melanin produced, the lighter the skin tone is. The researchers found that using keratinocytes from light-skinned people had a lightening effect on the bioengineered skin graft material, while keratinocytes from dark-skinned people had a darkening effect. This is incredibly important because it is the first conclusive piece of research that shows a solid link between keratinocytes and melanocytes. Additionally, keratinocytes are much easier to manipulate than melanocytes are.
Dr. Gerald Weissmann, Editor-in-Chief of the FASEB journal reported that the skin grafts were engineered so that they closely resemble the natural tone and color of the recipient, which was hypothesized to reduce the visibility of scarring. He also noted that this study is the beginning to unleashing the understanding of how and why different skin tones have evolved during the millions of years that humans have been in existence.
While it may seem that this study is only significant in the cosmetic world of medicine, this is not completely the case. The study’s senior researcher, Dr. Raymond Boissy, said that this study could also help to improve the quality of life for people suffering from pigment diseases such as melasma, vitiligo, and age spotting by making their skin look healthier. Melasma is a tan or dark facial discoloration most commonly seen in pregnant women and women on hormone replacement therapy. Vitiligo is a chronic skin condition that causes loss of pigment, resulting in irregular patches of pale skin scattered throughout the patient’s body. Perhaps if vitiligo and melasma patients had skin grafts enhanced with fully functional keratinocytes and melanocytes, the production and distribution of melanin could be altered so that the light patches of skin would gradually become darker, the dark patches of skin would gradually become lighter, thus patients would have a more even skin tone and an improved quality of life.
Date of Publication: August 26, 2007
Found in: Medical Research News
Scientists from the University of Cincinnati and Tokyo Medical University have been searching for ways to make human skin look healthier and younger by manipulating skin tone and color. While your mind may jump right to Michael Jackson’s horrendously bleached skin, the researchers are not looking for ways to improve skin bleach. They are looking to bioengineered skin grafts as a way to even out the colors and tones of skin that is either discolored or has patches of discoloration.
Part of the function of these bioengineered skin grafts is to help cosmetic companies develop new products so that people can achieve the perfect sunless tan. These skin grafts are not meant for people who wish to completely change the color of their skin, although this is a concern that must be addressed sooner than later. If this is not addressed, it is possible that people with light-colored skin who wish to be darker and people with dark-colored skin who wish to be lighter will subject themselves to whole body skin grafts to achieve a complete change in skin color. This would exponentially increase racial tensions nationwide, and possibly worldwide. However, once this kind of scientific advancement is made, it is quite a challenge to keep it out of the hands of the wrong people. This dilemma is similar to the debate about screening embryos for genetic predispositions to develop certain inherited diseases. While that is generally seen as positive, some people are against it because they believe that screening embryos will lead to the age of designer babies, which is seen by many as unethical. The line is just as fine for this research study: why is it socially acceptable to have skin darkened so that it is tanner, but not socially acceptable to have skin lightened? It seems as if making your skin darker is not perceived as wanting to change your racial identity, while making your skin lighter is.
The research study was published in the September issue of the Federation of American Societies for Experimental Biology journal (FASEB), and explained how, for the first time, scientists were able to manipulate skin color and tone by using cells that were previously thought to play no significant role in skin tone and color.
Researchers describe how the cells responsible for pigmentation, melanocytes, can be controlled by keratinocytes, the most commonly occurring skin cells. Keratinocytes make up 90% of epidermal cells (the cells on the outermost layer of the skin) and do not produce any pigment of their own. Working with bioengineered skin that is usually used for skin grafts to help burn victims recover posed a couple of difficulties for the researchers because they had to balance various mixtures of keratinocytes from people with vastly different types of skin colors and tones. The keratinocytes were found to produce chemical signals that tell the melanocytes to produce more or less pigment, called melanin, as well as how to distribute the pigment that they produced. Distribution is really important because it insures that the skin has even tones and colors and that there are not any patches of skin that are radically different colors from the rest of the skin on a person.
It has been known for a while that the more melanin produced, the darker the skin tone is, and conversely, the less melanin produced, the lighter the skin tone is. The researchers found that using keratinocytes from light-skinned people had a lightening effect on the bioengineered skin graft material, while keratinocytes from dark-skinned people had a darkening effect. This is incredibly important because it is the first conclusive piece of research that shows a solid link between keratinocytes and melanocytes. Additionally, keratinocytes are much easier to manipulate than melanocytes are.
Dr. Gerald Weissmann, Editor-in-Chief of the FASEB journal reported that the skin grafts were engineered so that they closely resemble the natural tone and color of the recipient, which was hypothesized to reduce the visibility of scarring. He also noted that this study is the beginning to unleashing the understanding of how and why different skin tones have evolved during the millions of years that humans have been in existence.
While it may seem that this study is only significant in the cosmetic world of medicine, this is not completely the case. The study’s senior researcher, Dr. Raymond Boissy, said that this study could also help to improve the quality of life for people suffering from pigment diseases such as melasma, vitiligo, and age spotting by making their skin look healthier. Melasma is a tan or dark facial discoloration most commonly seen in pregnant women and women on hormone replacement therapy. Vitiligo is a chronic skin condition that causes loss of pigment, resulting in irregular patches of pale skin scattered throughout the patient’s body. Perhaps if vitiligo and melasma patients had skin grafts enhanced with fully functional keratinocytes and melanocytes, the production and distribution of melanin could be altered so that the light patches of skin would gradually become darker, the dark patches of skin would gradually become lighter, thus patients would have a more even skin tone and an improved quality of life.
Saturday, November 17, 2007
Genetically Altered Cells May Help Artificial Skin Fight Infection
Title: Genetically Altered Cells May Help Artificial Skin Fight Infection
Author: Amanda Harper
Date of Publication: January 9, 2007
Published in: Journal of Burn Care and Research
Study funded by: Shriners Hospitals for Children
Dorothy Supp, PhD and her burn research team in Cincinnati have created genetically modified skin cells that when added to cultured skin substitutes may help fight off potentially lethal infections in patients with severe burns. They found that skin cells genetically altered to make higher levels of the tiny protein human beta defensin 4 (HBD4), which naturally exist in the body as part of its defense system, were able to kill more bacteria than normal skin cells. This is important because infections are a serious risk for patients who have recently received skin grafts.
The cells are taken from the patients’ own skin, cultured in a laboratory, then are expanded and combined with a spongy layer of collagen to make the actual skin grafts that can be reattached to the wound. It is good that the cells are taken from the patients’ own skin because the patients won’t have to deal with seeing someone else’s skin on their body, which while medically effective has proven to be somewhat psychologically damaging. These psychological effects were seen in one of our lectures where hand amputatee and had another man’s hand sewn on to his residual limb. While surgeons spent many painstaking hours attaching each blood vessel and nerve ending from the new hand to this man’s arm and the hand was functioning beautifully, the man could not deal with the psychological trauma of seeing another man’s hand instead of his own, and actually opted to get the hand removed and chose to have a prosthetic attached instead. However, what if the patient is so badly burned that there isn’t enough healthy skin from which to take cells to culture? Should the necessary skin cells come from a cadaver or an animal?
Supp has been conducting her study for three years and has learned how to successfully isolate the HBD4 gene from donated tissue samples and transfer it into surface skin cells, called keratinocytes, to give them enhanced infection-fighting abilities. These cells are then infected with pseudomonas aeruginosa, a type of bacteria most commonly found in hospitals, and allowed to incubate. When analyzed, Supp discovered that the genetically altered cells containing HBD4 were more resistant to microbial infections that the unaltered cells. These cells, if effective, could become an alternative method for burn wound care as well as for infection control in general.
If they are used in cultured skin substitutes, they may also decrease the patients’ risk for infection, improve skin graft survival and hopefully reduce the patients’ need for antibiotic treatment. Currently, physicians have to continually wrap the skin graft surgical wound in dressings coated in antimicrobial drugs to fight off infection. This is a time consuming process that does not necessarily rule out infection since antibiotics have to be given to the patient topically and orally, increasing the risk of the emergence of drug-resistant strains of bacteria.
The goal is to add these genetically modified cells to bioengineered skin substitutes in the hopes that they will provide an essential boost to the body’s natural defense system during the initial grafting period, when the skin is most susceptible to infection. However, cultured skin substitutes do have an increased susceptibility to infection since they are not yet connected to the body’s circulatory system at the time of grafting, and are therefore not able to circulate antibiotic drugs or antibodies from the body’s immune system to fight off infection.
Author: Amanda Harper
Date of Publication: January 9, 2007
Published in: Journal of Burn Care and Research
Study funded by: Shriners Hospitals for Children
Dorothy Supp, PhD and her burn research team in Cincinnati have created genetically modified skin cells that when added to cultured skin substitutes may help fight off potentially lethal infections in patients with severe burns. They found that skin cells genetically altered to make higher levels of the tiny protein human beta defensin 4 (HBD4), which naturally exist in the body as part of its defense system, were able to kill more bacteria than normal skin cells. This is important because infections are a serious risk for patients who have recently received skin grafts.
The cells are taken from the patients’ own skin, cultured in a laboratory, then are expanded and combined with a spongy layer of collagen to make the actual skin grafts that can be reattached to the wound. It is good that the cells are taken from the patients’ own skin because the patients won’t have to deal with seeing someone else’s skin on their body, which while medically effective has proven to be somewhat psychologically damaging. These psychological effects were seen in one of our lectures where hand amputatee and had another man’s hand sewn on to his residual limb. While surgeons spent many painstaking hours attaching each blood vessel and nerve ending from the new hand to this man’s arm and the hand was functioning beautifully, the man could not deal with the psychological trauma of seeing another man’s hand instead of his own, and actually opted to get the hand removed and chose to have a prosthetic attached instead. However, what if the patient is so badly burned that there isn’t enough healthy skin from which to take cells to culture? Should the necessary skin cells come from a cadaver or an animal?
Supp has been conducting her study for three years and has learned how to successfully isolate the HBD4 gene from donated tissue samples and transfer it into surface skin cells, called keratinocytes, to give them enhanced infection-fighting abilities. These cells are then infected with pseudomonas aeruginosa, a type of bacteria most commonly found in hospitals, and allowed to incubate. When analyzed, Supp discovered that the genetically altered cells containing HBD4 were more resistant to microbial infections that the unaltered cells. These cells, if effective, could become an alternative method for burn wound care as well as for infection control in general.
If they are used in cultured skin substitutes, they may also decrease the patients’ risk for infection, improve skin graft survival and hopefully reduce the patients’ need for antibiotic treatment. Currently, physicians have to continually wrap the skin graft surgical wound in dressings coated in antimicrobial drugs to fight off infection. This is a time consuming process that does not necessarily rule out infection since antibiotics have to be given to the patient topically and orally, increasing the risk of the emergence of drug-resistant strains of bacteria.
The goal is to add these genetically modified cells to bioengineered skin substitutes in the hopes that they will provide an essential boost to the body’s natural defense system during the initial grafting period, when the skin is most susceptible to infection. However, cultured skin substitutes do have an increased susceptibility to infection since they are not yet connected to the body’s circulatory system at the time of grafting, and are therefore not able to circulate antibiotic drugs or antibodies from the body’s immune system to fight off infection.
Monday, November 12, 2007
Cadaver Skin Fills the Gap in Burn Cases
Title: Cadaver Skin Fills the Gap in Burn Cases
Author: Amanda Schaffer
Source: The New York Times
Publication: May 2, 2006
Although much new and innovative progress is being made toward the creation of artificial skin products for grafting, the treatment for burn patients chugs along, relying on older, more traditional methods. In the May 2006 New York Times article by Amanda Schaffer, “Cadaver Skin Fills the Gap in Burn Cases,” the reality of skin grafting and the most common source of skin for grafting—cadavers—is described and evaluated.
Cadaver skin, the most favorable option for grafting (aside from autologous grafts) over the past 40 years, has thoroughly cemented itself as a significant player in the realm of skin grafting. The skin is harvested from donors very soon after death; however, the process of searching for and locating viable donors can be difficult and unfruitful. Cadavers are only eligible after extensive testing for risk factors that may harm the patient, and even if the skin is deemed perfect for skin grafting, the family of the deceased must consent to the procedure.
The article clearly outlines the process involved in preserving cadaver skin. Any given cadaver can yield approximately four square feet of skin, and once removed, the skin is sliced into strips and stored in freezing temperatures. When needed for a graft, the skin is removed, put through a meshing machine to facilitate stretching of the skin, and subsequently attached to the affected burn area.
Cadaver skin has clear advantages for use in skin grafting. Using human skin instead of the new and exciting artificial skin products in development can lessen the chance for infection and quicken the healing process. Since it is a real human organ, graft patients may not feel as much of a difference between their unharmed and the transplanted skin. Logistically, cadaver skin is beneficial because it can be effectively stored for up to five years.
Although the article was thorough when describing the process of cadaver skin use and introducing several of the new research endeavors to create artificial skins such as Integra and Epicel, the path to becoming a skin donor and the function of skin banks were not heavily discussed. Schaffer briefly mentions that patients undergoing gastric bypass surgery who would like to donate excess skin cannot do so due to the shortcomings of current skin harvesting procedures—but doesn’t follow up to explain the techniques or why they are inadequate.
Becoming a skin donor may seem very straightforward — in many states, preference regarding organ donation can be listed right on the driver’s license. However, as previously mentioned, the family of the deceased must agree to allow skin to be removed after death, and when faced with the decision, many relatives refuse the procedure. “Skin donor program will help treat burn victims,” appearing in the Atlanta Business Chronicle, articulated the reality that many families are uncomfortable with this idea of skin donation— after all, how many people would agree to let their loved ones be ‘skinned’ before the funeral service? The thing that most families do not realize, however, is that grafts are mainly harvested from inconspicuous areas, such as the thighs and buttocks. These grafts can be extremely beneficial for burn victims whose bodies have been destroyed in tragic fire accidents. [@http://www.bizjournals.com/atlanta/stories/2000/10/30/focus6.html].
Should the decision to be a donor be less optional? In the
The endeavor to improve the effectiveness of cadaver skin grafting should be addressed with at least as much importance as the ventures to innovate artificial skins and new techniques for grafting procedures. Why? The enhancement of a pre-existing, proven-to-work method seems a wise path to pursue—after all, if cadaver skin grafting became easier and more accessible, maybe the development of synthetic grafts would not be as pressing of a matter. Perhaps the focus and efforts in the field should be centered on the advancement of current procedures rather than the creation of new ones. Unfortunately though, the funding for research and development is most often awarded to the companies pursuing the most exciting and ingenious new products and techniques. This reality may signal a need for reevaluation, in some situations, of the priorities that biotechnology strives to achieve. In this case especially, shifting the focus and resources to more basic forms of education and training may significantly benefit the given medical arena.
-JG
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