Meningitis: Researchers Find Possible Treatment Strategy Without Antibiotics

Meningitis is a very serious brain infection with limited treatment options. In a new study performed in rats, researchers from the University of Copenhagen present an alternative treatment based on immune cells that helps rinse away toxins that accumulate during the infection.

Fever, headache, confusion, seizures, amputations or death. Meningitis is a very serious brain infection that can affect the body in many ways and needs to be treated within 24 hours of contracting the disease. The World Health Organization estimates that there are close to three million cases per year. Between the four main causes of meningitis, the WHO is particularly concerned about bacterial meningitis, which is caused by the infectious bacteria Streptococcus pneumoniae.

Despite widespread implementation of vaccines, bacterial meningitis is still associated with a high mortality rate and neurological consequences including hearing loss, focal neurological deficits and cognitive impairment, estimated to occur in close to half of surviving patients.

Antibiotictreatment is necessary, but with the increasing threat of antibiotic resistance, there is a growing need for new treatment strategies.

Now, in a new study performed on rats, researchers from the University of Copenhagen and Lund University were able to utilize the body’s own immune cells to kill the bacterial meningitis infection.

“In a rat model, we observed that the neutrophils, a type of immune cells, form a net-like structure in the brain’s membrane, the meninges. But this particular net structure also causes brain swelling and prevents the removal of waste products. We discovered, that if we dissolved the structure – not the immune cells – the immune cells still kill the meningitis bacteria but without causing brain swelling,”

The researchers show that immune cells entering the brain’s membrane create a net that traps bacteria but also blocks the movement of cerebrospinal fluid. The brain is constantly cleaned by the cerebrospinal fluid that enters the tissue along blood vessels and is responsible for clearing out waste products made by the active brain cells.

This fluid transport system was named the glymphatic system by Maiken Nedergaard, and its function has been shown to be critical for avoiding the accumulation of protein plaques that accumulate in patients with Alzheimer's disease. Glymphatic transport of cerebrospinal fluid is also important for avoiding brain swelling in acute diseases such as stroke.

Brain swelling, also called edema, is a life-threatening condition because the brain is contained within the skull. The swelling compresses blood vessels resulting in loss of brain tissue, which is fatal when the brain region that controls breathing stops working.

That brain swelling in meningitis is caused by blockage of the glymphatic system is now shown for the first time in collaboration between Maiken Nedergaards group at the University of Copenhagen and Iben Lundgaard at Lund University.

“When the immune cells enter the brain, they eat the bacteria, but while doing so the immune cells also produce inflammatory components, including nets that cause swelling,” says Maiken Nedergaard, the lead author from the University of Copenhagen. This novel treatment can be combined with antibiotics if needed,” she says. Hope for an international clinical study.