|
Tuberculosis: The bacillus takes refuge in adipose cells
December 21, 2006A team from the Institut Pasteur has recently shown that the tuberculosis bacillus hides from the immune system in its host's fat cells
A team from the Institut Pasteur has recently shown that the tuberculosis bacillus hides from the immune system in its host's fat cells. This formidable pathogen is protected against even the most powerful antibiotics in these cells, in which it may remain dormant for years. This discovery, published in PLoS ONE, sheds new light on possible strategies for fighting tuberculosis. Attempts to eradicate the bacillus entirely from infected individuals should take these newly identified reservoir cells into account.
Mycobacterium tuberculosis, the bacillus responsible for tuberculosis can hide, in a dormant state, in adipose cells throughout the body. The bacterium is protected in this cellular environment, to which the natural immune defences have little access, and is inaccessible to isoniazid, one of the main antibiotics used to treat tuberculosis worldwide. These results were obtained by Olivier Neyrolles* and his colleagues from the Mycobacterial Genetics Unit directed by Brigitte Gicquel at the Institut Pasteur, in collaboration with Paul Fornîs, a pathologist from Hôpital Européen Georges Pompidou. They raise questions of considerable importance in the fight against tuberculosis.
Tuberculosis kills almost two million people worldwide every year and is considered by the World Health Organisation to represent a global health emergency. However, the bacillus is much more prevalent in the world's population than the statistics would lead us to believe, because only 5 to 10% of those infected actually develop tuberculosis. The bacillus may be present in a significant proportion of the population, remaining in a "dormant" state in the body, sometimes for years, and may be "reactivated" at any time. The risk of rea ctivation is particularly high in immunocompromised individuals, such as those infected with AIDS: the HIV virus and the tuberculosis bacillus make a formidable team, with each infectious agent facilitating the progression of the other.
Neyrolles' team first demonstrated, in cell and tissue cultures, that adipose cells served as a reservoir for Mycobacterium tuberculosis, and that this protected the bacillus against isoniazid. They then investigated whether the pathogen was present in adipose cells in humans. They did this by testing for traces of the genetic structure of the bacillus in samples from people considered not to be infected. Analyses were carried out on samples from deceased subjects from Mexico, where tuberculosis is endemic, and from Parisian districts reporting very few cases of tuberculosis.
The bacterium was detected in the adipose tissue of about a quarter of these people, all of whom were unaware they were infected, in both Mexico and France. These results suggest that the bacillus responsible for tuberculosis can remain protected in the adipose tissue of the body in the absence of any sign of disease.
This work has important implications for the prevention of this disease. It helps to explain how, many years after first testing positive for tuberculosis, people with no trace of the microbe in the lungs may develop some form of tuberculosis attacking the lungs, bones or genitals. It also suggests that isoniazid treatment, prescribed to the close friends and family of patients as a preventative measure, may in some cases not provide sufficient protection against the disease. This is particularly important for immunocompromised patients and for people with AIDS, for whom a secondary infection with tuberculosis bacillus may have very serious consequences.
This work highlights the importance of the search for new targeted therapeutic weapons, such as new antibiotics, which must be able to reach the dormant bacillus that has been hiding in adipose cells without our knowing it.
Public Library of Science
Tuberculosis kills almost two million people worldwide every year and is considered by the World Health Organisation to represent a global health emergency. However, the bacillus is much more prevalent in the world's population than the statistics would lead us to believe, because only 5 to 10% of those infected actually develop tuberculosis. The bacillus may be present in a significant proportion of the population, remaining in a "dormant" state in the body, sometimes for years, and may be "reactivated" at any time. The risk of rea ctivation is particularly high in immunocompromised individuals, such as those infected with AIDS: the HIV virus and the tuberculosis bacillus make a formidable team, with each infectious agent facilitating the progression of the other.
Neyrolles' team first demonstrated, in cell and tissue cultures, that adipose cells served as a reservoir for Mycobacterium tuberculosis, and that this protected the bacillus against isoniazid. They then investigated whether the pathogen was present in adipose cells in humans. They did this by testing for traces of the genetic structure of the bacillus in samples from people considered not to be infected. Analyses were carried out on samples from deceased subjects from Mexico, where tuberculosis is endemic, and from Parisian districts reporting very few cases of tuberculosis.
The bacterium was detected in the adipose tissue of about a quarter of these people, all of whom were unaware they were infected, in both Mexico and France. These results suggest that the bacillus responsible for tuberculosis can remain protected in the adipose tissue of the body in the absence of any sign of disease.
This work has important implications for the prevention of this disease. It helps to explain how, many years after first testing positive for tuberculosis, people with no trace of the microbe in the lungs may develop some form of tuberculosis attacking the lungs, bones or genitals. It also suggests that isoniazid treatment, prescribed to the close friends and family of patients as a preventative measure, may in some cases not provide sufficient protection against the disease. This is particularly important for immunocompromised patients and for people with AIDS, for whom a secondary infection with tuberculosis bacillus may have very serious consequences.
This work highlights the importance of the search for new targeted therapeutic weapons, such as new antibiotics, which must be able to reach the dormant bacillus that has been hiding in adipose cells without our knowing it.
Public Library of Science
Tuberculosis News and Current Tuberculosis Events RSSNew Electrostatic-based DNA Microarray Technique Could Revolutionize Medical Diagnostics
The dream of personalized medicine - in which diagnostics, risk predictions and treatment decisions are based on a patient's genetic profile - may be on the verge of being expanded beyond the wealthiest of nations with state-of-the-art clinics.
Predicting TB outbreaks based on the first 2 cases
Outbreaks of tuberculosis (TB) may be able to be identified by looking at certain characteristics of the first two patients, according to new research.
Radical reform is needed to stop the 'inhumane' practice of transplant tourism
The UK government must bring in presumed consent to organ donation or allow a controlled donor compensation programme for unrelated live donors, in order to bring the "inhumane" practice of transplant tourism from the UK to an end, claims a doctor in this week's BMJ.
Pitt-led Researchers Find Source of Drug-Tolerant Tuberculosis Possibly Behind TB Relapses, Intensity of Treatment
University of Pittsburgh-led researchers discovered that the primary bacteria behind tuberculosis can grow on surfaces and that drug-tolerant strains flourish in these bacterial communities, the research team recently reported in "Molecular Microbiology."
US soldiers in high-tuberculosis areas face new epidemic: false positives
U.S. Army service members are increasingly deployed in regions of the world where tuberculosis (TB) is rampant, such as Iraq and Afghanistan, and the military now faces a growing medical problem.
Tuberculosis not the only risk from new immunological drugs
A new survey cautions physicians that drugs commonly prescribed for patients suffering from immunological disorders such as rheumatoid arthritis and inflammatory bowel disease may carry risks of serious infections other than the known risk of tuberculosis.
Pilot study reinforces use of portable anteroom HEPA filtration
Amidst an increase in new tuberculosis cases, researchers have begun investigating the effectiveness of new operating room filtration systems designed to protect staff and patients.
X-rays power discoveries at Chicago's Field Museum
Digital medical imaging and information technology from Carestream Health, Inc., is playing a key role in helping The Field Museum of Chicago discover and analyze secrets hidden within its world-class collections.
Study shows common vitamin and other micronutrient supplements reduce risks of TB recurrence
New findings show a link between micronutrient supplementation and reduced risk of recurrence during tuberculosis chemotherapy, according to a study published in the June 1 issue of The Journal of Infectious Diseases, now available online.
NIAID describes research priorities to fight drug-resistant tuberculosis
Tuberculosis (TB) has long been one of the world's great killers. Now, forms of drug-resistant TB--multidrug (MDR) and extensively drug-resistant (XDR)--are occurring at an ominous and accelerating rate.
More Tuberculosis News Articles
 | The Air We Breathe: A Novel by Andrea Barrett |
 | Illness as Metaphor and AIDS and Its Metaphors by Susan Sontag |
 | The Bioarchaeology of Tuberculosis: A Global View on a Reemerging Disease by CHARLOTTE ROBERTS, JANE BUIKSTRA |
 | Towns of the Sandia Mountains (NM) (Images of America) by Mike Smith |
 | The White Plague: Tuberculosis, Man, and Society by Rene J. Dubos |
 | Harvey Girl by Sheila Wood Foard |
 | The Night Journal by Elizabeth Crook |
 | The Return of the White Plague: Global Poverty and the 'New' Tuberculosis |
 | Virgin River: A Barnaby Skye Novel (Skye's West) by Richard S. Wheeler |
 | Behold the Many: A Novel by Lois-Ann Yamanaka |
| © 2008 BrightSurf.com |