Last fall investigators at the University of Texas Health Science Center at San Antonio demonstrated how infections triggered by Streptococcus pneumoniae could damage the heart, explaining why older adults hospitalized for pneumonia were at a high risk for often lethal complications. And a multidisciplinary team led by Professor Aras Kadioglu and Professor Cheng-Hock Toh at the University of Liverpool say the likely culprit--the toxin pneumolysin--can be neutralized by engineered fat bodies called liposomes.
According to the team, the liposomes bind to pneumolysin and prevent damage to heart muscles. The same investigators have used liposome therapies (liposomes are "vesicles" used to deliver therapies) to treat pneumonia, sepsis caused by Streptococcus pneumoniae and MRSA.
"We have discovered that the toxin pneumolysin, which is released during infection with Streptococcus pneumoniae, is the main reason why a significant number of patients develop rapidly progressive and fatal heart complications even if the bacteria does not directly infect the heart," said Yasir Alhamdi, lead author of the study.
Using antibiotics in these cases may actually make the damage worse, according to the team.
"We have now shown that liposomes can also be used therapeutically to combat deadly heart complications that accompany infections caused by Streptococcus pneumoniae," said Daniel Neill. "This exciting new finding demonstrates that liposomes may also be of use in conjunction with antibiotics to mitigate the pathological effects of antibiotic-induced bacterial lysis."
The study was funded by the British Heart Foundation and the Medical Research Council. The paper, "Circulating pneumolysin is a potent inducer of cardiac injury during pneumococcal infection," is published in the journal PLOS Pathogens.
- here's the release