Researchers at the Massachusetts General
Hospital Burn Research Center are particularly interested in the
role the body's metabolism plays in responding to a severe injury.
Injuries caused by burns and serious tissue damage caused by severe
trauma have effects that extend way beyond the skin's surface.
Skin is much more than a coating for the body. It is a living organ
— the largest in the body — that contains immune cells,
blood vessels, nerve cells, and many other protective components.
Skin consists of multiple layers, and deep burns and severe physical
trauma tear through the full thickness of skin. This leaves the
body vulnerable to infections and fluid loss, both of which put
an injured patient at high risk for further medical complications.
Center researchers were the first to prove that as a routine clinical
treatment, the critical first step is removal of the damaged skin
followed by immediate covering of the wound.
Serious injury from burn and/or trauma affects many organ systems.
Center researchers have long been interested in these body-wide
changes. For example, they have discovered that after a burn, the
body's metabolism goes into high gear, burning up to twice as many
calories as usual. Compounding the serious issues of infection and
fluid loss, a badly-burned body begins to turn on itself, consuming
cellular components faster than the body can replenish them. Scientists
believe that this "catabolic" effect is in some way related
to an overall increased metabolic rate in burned patients. For some
unknown reason, certain body organs such as liver and muscle are
affected more than others. This is a major focus of effort for Center
scientists, who are currently using sophisticated imaging technologies
to evaluate metabolic differences between organs.
Even though a badly injured body has a higher metabolic rate, burning
more calories than usual, overfeeding can cause even more problems.
The role of proper nutrition in caring for injured patients is surprisingly
complex. For example, scientists have found that administering too
much of the natural sugar glucose intravenously to injured patients
can lead to liver damage and breathing complications. On the other
hand, giving an injured patient a high-protein, high-carbohydrate
diet by mouth, or by a feeding tube that delivers nutrients directly
to the stomach or intestines, can maintain body weight and lead
to a better recovery. Research suggests that this is likely to be
primarily due to the fact that most injured patients' digestive
systems are relatively intact and can act as a barrier against infection.
Center scientists are currently studying the amino acid metabolism,
a key process in the body's production of proteins.
One of the reasons researchers suspect that a high-carbohydrate
diet can speed recovery from injury is that these natural body sugars
promote insulin production. Insulin, in turn, has a reverse effect
on catabolism. Center researchers are actively pursuing the role
of insulin in recovery from injury, especially the perplexing phenomenon
of insulin resistance that can develop in severely burned patients.
Interestingly, another factor that influences a burned patient's
metabolic rate is ambient temperature. Scientists have learned that
a warm environment (82 to 91 degrees Fahrenheit) can also tone down
the body's catabolic response. It is believed that this occurs because
the body tries to compensate for water loss through burned skin
by raising its core temperature. Increasing the temperature of the
room appears to offset this response. Other factors also play a
role: Pain and anxiety, for instance, can increase a burned patient's
metabolic rate, making his or her condition worse.
With knowledge accumulated over the years, Center researchers are
studying ways to counter the body's catabolic effects. Some of this
research has revealed the importance of exercise after a burn. A
comprehensive rehabilitation program that includes certain resistance
exercises can markedly improve the recovery process of severely
injured patients. Some natural hormones involved in growth can also
help the body absorb important nutrients and amino acids (the building
blocks for proteins). Scientists have discovered that giving injured
patients growth hormone (available as a drug) improves wound healing
and reduces scarring. In addition, when burned children are given
growth hormone, researchers have observed positive, long-term effects
on bone growth. Center researchers have also discovered that drugs
that block the body's "fight-or-flight" stress response
have been shown to improve outcome by protecting the heart, reducing
metabolic rate, and preventing muscle loss. Current Center research
efforts in this area focus on the molecular and cellular aspects
of muscle weakness and severe muscle wasting.
The new Center funded in 2013 builds on the previous success and experience
of our longstanding Burn Trauma Center. The focus of the Center has now
shifted towards the implications of insulin resistance in the context of
muscle wasting and is driven by the realization that insulin therapy has
failed to reverse the pathophysiological derangements, thus necessitating new,
cellular and molecular based approaches. Using newly analyzed gene and protein
information from the Inflammation and the Host Response to Injury Glue Grant
together with the focused projects, the Center researchers should be able to
generate important and novel data to address the complex mechanisms resulting
in muscle wasting and insulin resistance after burn injury. Advancing
the understanding should provide the Center investigators with unique
opportunities to develop effective therapeutic approaches to lessen the
effects of two of the underlying clinical problems that often accompany major burn injury.
To learn about the development of artificial
skin at MGH, click here.