How this crab could save your life?

Although we can’t see them, microorganisms such as viruses and bacteria surround us. Most of them are beneficial, but there are some that cause diseases.

Bacterial infections are one of the most frequent causes of death worldwide. Bacterial pathogens can reproduce quickly in our bodies and, depending on where they grow, they cause pneumonia (lungs), appendicitis (appendix), cystitis (urinary bladder)… among many others. If these infections are not controlled, bacteria might reach the blood torrent and cause sepsis, which can develop into multiorgan failure and posterior death.

Animals have learned to evolve in a constant battle against these pathogens using their immune system. Normally, bacterial infections are eliminated by our production of antibodies, but sometimes it is not enough.

Luckily, since Alexander Fleming discovered Penicillin in 1928, antibiotics are now considered our best ally in the fight against bacterial infections. Thanks to this, bacterial-related deaths have dropped constantly during the second half of XX century. However, due to an inappropriate use of antibiotics, bacteria have evolved and developed resistance to our treatments. Since the last years, difficult-to-treat infections are causing a rise in mortality, which enhances the necessity of new drugs.

Surprisingly, the problem of bacterial infections might have been solved long time ago, at least for one animal. The horseshoe crab, Limulus polyphemus, is a living fossil with (literally) blue blood that has been on earth for 450 million of years. It possesses a cell type called Limulus amebocyte lysate (LAL) that has been demonstrated to protect efficiently against bacterial infections. LAL is being used for detection and quantification of bacterial endotoxin, which is a molecule located on the layer of some bacterial membrane.

Scientists have investigated LAL in great detail and, as a consequence of this, novel drugs are currently being studied. In our group, at the Department of Microbiology and Parasitology of University of Navarra, we are focused on an antimicrobial component, Aspidasept®, whose structure is based on LAL properties. This novel drug interacts with bacterial toxins, causing its inactivation. In addition, this molecule interacts and destabilizes bacterial membranes.

Aspidasept® is now being studied in collaboration with Brandenburg Antiinfektiva GmbH and Forschingszentrum Borstel as a novel therapy for general bacterial infections. Specifically, we are testing its effectiveness when this compound is combined with antibiotics. We have demonstrated that our compound can facilitate massive antibiotic entry across bacterial membranes, which causes bacterial sensitization to antibiotics. At the moment, we have successfully tested Aspidasept® in mice and rabbit models against a group called Gram-negative bacteria. But studies indicate that this component can also be effective against Gram-positive bacteria.

This could help to treat multi-drug resistant infections and, hopefully, take a step towards bacterial-related deaths eradication. And all this thanks to an old crab…

Department of Microbiology and Parasitology of University of Navarra: http://www.unav.edu/departamento/microbiol/

Brandenburg Antiinfektiva GmbH: http://www.antiinfektiva.com/en/company

Forschingszentrum Borstel: http://www.fz-borstel.de/cms/

Sergio Bárcena Varela
Department of Microbiology and Parasitology of University of Navarra