New Hope For Strep Sufferers
Investigators at The Methodist Hospital Research Institute in Houston examined for the first time the long-term response to strep throat on a genome-wide level, shedding light on how group A streptococcus interacts with the patient’s immune system and attempts to circumvent it.
The results of the study were published in the Proceedings of the National Academy of Sciences (PNAS). In the U.S., the human bacterial pathogen group A streptococcus causes an estimated 30 million cases of strep throat annually, and also causes rheumatic fever that damages the heart.
“This study has discovered previously unknown ways that a common bacterial pathogen communicates with its host during an infection episode. The result is a new, much higher level of understanding of how infection causes disease,” said Dr. James Musser, senior scientist on the study and co-director of The Methodist Hospital Research Institute. “These discoveries have already provided a wealth of information for future research into new treatments and vaccines, not only for strep throat, but also for other types of life threatening group A strep infections as well.”
“Our results are significant because despite the prevalence of strep throat, currently relatively little is known about what happens on a molecular level regarding interaction between group A streptococcus and the host during a throat infection,” said Dr. Patrick Shea, scientist at TMHRI who is the first author of the study. “Advances in genome-wide analyses occurring in the last decade have facilitated the study of global gene changes that occur during microbial infection, giving us important new clues on how better to fight and prevent infections.”
Stem Cells Helpful in Spinal Cord Injury
 Researchers at the University of Texas Health Science Center (UT Health) at Houston have demonstrated in rats that transplanting genetically modified adult stem cells into an injured spinal cord can help restore the electrical pathways associated with movement.
In spinal cord injury, demyelination, or the destruction of the myelin sheath in the central nervous system, occurs. The myelin sheath, produced by cells called oligodendrocytes, wraps around the axons of nerves and helps speed activity and insulate electrical conduction. Without it, the nerves cannot send messages to make muscles move. The results are published in the Journal of Neuroscience.
The research team, led by Qilin Cao, M.D., principal investigator and associate professor of neurosurgery at UT Health, discovered that transplanted adult stem cells (oligodendrocyte precursor cells or OPC) from the spinal cord could become oligodendrocytes. The new cells helped restore electrical pathways of the spinal cord and therefore, function, in a process called remyelination.
Cao said two important discoveries were isolating precursor cells from the adult spinal cord and, prior to transplanting them into the spinal cord, genetically modifying them to express ciliary neurotrophic factor (CNTF), a protein that encourages nerve growth. In preliminary experiments, CNTF was shown to facilitate survival and differentiation of OPCs in cell culture.
“Most importantly, the evidence of remyelination was shown to exactly coincide with the anatomical localization of these motor pathways in spinal cord white matter,” Cao said. “These latter data provide confidence that the mechanism by which the grafted OPCs are enhancing functional recovery is through remyelination.”
Previous studies by the team and other researchers have shown that grafted OPCs survive after grafting into an injured spinal cord and increase movement recovery, but the mechanical connection to remyelination had only been theorized. In this research, results showed that there was significantly enhanced behavioral recovery, return of electrophysiological conduction and ultra-structural evidence of remyelination.
The clinical significance is two-fold, Cao said: “First it confirms what has been suggested by these and other authors that stem cell grafting in attempts to remyelinate an injured spinal cord is a viable therapeutic strategy. Secondly, it strongly cautions that optimal recovery using such an approach will require more than simply grafting naïve precursor cells.”
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