Researchers from the University of Calgary have discovered a potentially effective new method for treating bacterial skin infections. Dr. Rachel Kratofil, Ph.D., the study’s first author, and co-senior authors Drs. Paul Kubes, Ph.D., and Justin Deniset, Ph.D., along with their research team, recently published a study in Nature that offers fresh knowledge that can improve the treatment of bacterial infections and wounds.
It is exciting that we have made a fundamental discovery that could improve infections and tissue repair in humans, especially in difficult-to-treat cases, says Kratofil. However, moving our research from the bench to the bedside will necessitate many more experiments and involve a model more closely related to human disease.
Neutrophils and monocytes, two types of white blood cells, were once believed to be recruited to remove bacteria from an infected site on the skin. These cells function as the body’s initial line of defense for the immune system when they cooperate.
However, the most recent research shows that only monocytes can help wounds heal more quickly. By controlling leptin levels and blood vessel expansion during wound repair, monocytes support the healing process. They also produce ghrelin, a hormone that promotes faster wound healing.
Interestingly, metabolic hormones and tissue healing are related
When you are hungry, your stomach releases the hormone ghrelin, while fat cells release the hormone leptin when you have eaten and are feeling satisfied.
Until today, the relationship between ghrelin and leptin and immune systems and tissue healing was unknown. It has long been recognised that this balance between ghrelin and leptin is essential to metabolism and diet.
In an animal model, Kratofil was able to see the immunological response to Staphylococcus aureus (S. aureus) germs using intravital microscopy, a specialty of the Kubes Lab that permits monitoring of living cells.
S. aureus is a microbe that a healthy body frequently has on its skin or in its nose. It can be the starting point for a wide range of conditions including abscesses or boils that are caused by skin and tissue infections. The bacteria can occasionally cause serious infections such pneumonia and endocarditis, a potentially fatal inflammation of the heart.
The body enlists neutrophils and monocytes, those beneficial immune cells, after a S. aureus infection. Monocytes aid in tissue healing while neutrophils eliminate germs. In the lack of monocytes, leptin production is enhanced, which causes the infection’s blood vessel expansion. Scarring and a delay in recovery are potential outcomes. In contrast, leptin-driven excess blood vessel growth is blocked by ghrelin, which is produced by monocytes at the infection site and promotes tissue healing.
The significance of the study’s findings
“This study is significant because it challenges the conventional wisdom that neutrophils and monocytes eliminate germs. Our research emphasises the importance of monocytes in wound healing, “According to Kratofil.
The discovery, according to lead researcher Kubes and his research group, “opens the door for the introduction of metabolic hormones (ghrelin and leptin) in the disciplines of immunology and microbiology.”
As an illustration, Kubes says, “It will be intriguing to explore how ghrelin and leptin behave in different disease models, such as sterile damage or cancer, and to learn how these processes are affected when a patient has many concurrent diseases or conditions, such as obesity and diabetes.”
The researchers’ next step is to gain a better understanding of how immune cells like neutrophils function during infection. They are particularly curious about how infections are cleaned from neutrophils and whether neutrophils do any other tasks besides clearing bacteria.
The 133 independent experiments conducted by this research team in collaboration with the labs of Dr. Keith Sharkey, Ph.D. (Snyder Institute, Hotchkiss Brain Institute (HBI)), Dr. Jeff Biernaskie, Ph.D. (HBI and Alberta Children’s Hospital Research Institute), and scientists from University Hospital Regensburg, Germany, and Texas A&M University resulted in the interdisciplinary work that has been published.