- Lactate is an
important substrate for energy, especially for cardiac output.
- When it is
present in the upper respiratory tract, it leads to detachment of colonies
of meningitis-causing bacteria.
- The detached
bacteria enter the blood stream, leading to severe infection.
is a byproduct of glucose metabolism
and it is
used as a substrate for energy production during exercise. However, a research
team from Stockholm University in Sweden has found that lactate produced in the
upper throat, could lead to the detachment of small colonies of
meningitis-causing bacteria, resulting in the spread of the bacteria to the
rest of body due to invasion into the blood. This study, published in PLOS
, describes the colonization of the bacterium Neisseria meningitides
in the upper respiratory tract.
bacterium Neisseria meningitides
found in the upper respiratory tract in 10
of people in the upper respiratory tract but it is harmless, in most
instances. Sometimes, this bacterium could invade the body and lead to
infection, called meningitis
‘Lactate is a substrate for energy and is found to trigger an invasion of the meningitis-causing bacteria into the blood.’
Mechanism of Infection
process of infection follows a two-step process:
- Colonies of the
bacteria first begin to develop in the upper throat
- These colonies
disperse and invade the lining of the mucosa, entering the blood stream
second step, the process of dispersal is not well understood. Dr. Sara
Sigurlásdóttir and colleagues tried to analyze if the dispersal of the colonies
was triggered by
any function or substance produced by the body.
initial studies carried out by the scientists, using live cell imaging, showed
that N. meningitidis
did not need to have a direct association with human cells. Instead, just being
present among a group of cells that contained human cells is
trigger enough for them to be dispersed.
were further studies that were conducted to identify the exact molecule that
acted as the trigger. The scientists found that the dispersal of the
meningitis-causing microcolonies was associated with the presence of the
The main function of lactate was found to be that of
a signaling molecule as it was not metabolized by N. meninitidis.
pathway of meningitis infection has never been detailed and this study attempts
to find an association between lactate as a trigger and the dispersal of these
microcolonies. The exact role of lactate has not been identified thus far, but
it could be a critical step in analyzing how a seemingly common and harmless
micro-organism colony could be dispersed and result in infection.
Ann-Beth Jonsson, a professor at Stockholm, said that the mechanism of action
of lactate as a signaling molecule was intriguing and that the vital steps
unveiled will help in preventing as well as treating meningococcal disease.
Lactate in the Body
glucose metabolism occurs on exercising the skeletal muscle; however, in the
case of cardio or heart exercise
, there is an increase in glucose metabolism initially, which
comes back to the decreased levels that are present during rest after the start
of high intensity exercise. There was a significant increase in serum lactate
after high intensity
exercises, which leads us to conclude that lactate as opposed to glucose is
utilized for cardiac energy production.
meningitis caused by Neisseria
is a serious condition and could become life threatening. It
is characterized by a swelling or an inflammation of the layer surrounding the
brain, the meninges. The infection of the fluid around the brain leads to the
inflammation. Since there are other bacteria and viruses which can cause
meningitis, it is important to identify the cause so that specific treatment
may be provided.
tests that are conducted to reveal the cause of meningitis take several days to
weeks, by which time precious time may be wasted. To overcome this situation,
scientists identified a new biomarker
for bacterial meningitis.
a study titled "Cerebrospinal fluid lactate level as a diagnostic biomarker for
bacterial meningitis in children" by Eduardo Mekitarian Filho and colleagues,
published in the International Journal of
, the effectiveness of cerebrospinal level of lactate was
used as a diagnostic marker. It is used to identify if the meningitis is caused
was found that the cerebrospinal fluid consisted of high lactate levels among children
who had meningitis
- Bacteria produced
lactate due to anaerobic metabolism
- Lactate was also
produced by ischemic brain tissue
ability to distinguish bacterial meningitis from other types of meningitis was
found to be possible using lactate levels in the cerebrospinal fluid.
current study that identifies the concentration of lactate as a key factor in
the dispersal of colonies of N.menigitidis
could be used as a means to understand the mechanism of disease progression and
can also be used as a new target for drug therapy against this potentially life
- Sara Sigurlásdóttir et al. Host cell-derived lactate functions as an effector molecule in Neisseria meningitidis microcolony dispersal. PLOS Pathogens, April 2017 DOI: 10.1371/journal.ppat.1006251
- Lactate - the forgotten fuel! - (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2290415/)
- Cerebrospinal fluid lactate level as a diagnostic biomarker for bacterial meningitis in children - (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3996047/)