#MultipleSclerosis #Microbiota #Immunity
#Probiotics
Multiple sclerosis (MS) is an
autoimmune
neurological disorder characterized by
chronic inflammation of the
central
nervous system (CNS) and the
progressive destruction of the myelin sheath
surrounding nerve fibers. This demyelination hinders the conduction of nerve
impulses, leading to motor, sensory, cognitive, and visual impairments. While
the exact origins of the disease remain incompletely understood, scientific
consensus increasingly points to the key role of
immune dysregulation. In
particular,
abnormal lymphocyte activation, excessive production of
pro-inflammatory cytokines, and
oxidative stress are recognized as key drivers
of the inflammatory response that leads to neurological damage.
In recent years, a new line of research has
emerged in the field of MS: the
gut microbiota. This vast bacterial ecosystem
is now acknowledged for its ability to continuously interact with the immune
system and the brain via the
“gut-brain axis.” Several experimental and
clinical studies have revealed
gut dysbiosis in MS patients, suggesting that
microbiota imbalance may promote an inflammatory environment conducive to
autoimmune activation.
It is in this context that probiotics come into
play: live microorganisms—most often lactic acid bacteria—capable of restoring
microbiota balance and favorably modulating the immune response. Proposed as an
innovative therapeutic approach in chronic inflammatory diseases, they are
generating increasing interest in neurology. This study aimed precisely to
synthesize available data from both preclinical studies (animal models of MS)
and clinical trials in humans to assess the actual potential of probiotics in
modulating the progression of MS.
Microbiota to the rescue?
To comprehensively assess the effect of
probiotics on multiple sclerosis, 23 studies were included in this analysis: 17
conducted on animal models (EAE) and 6 in human populations. The probiotics
evaluated mainly included strains of Lactobacillus, Bifidobacterium,
Prevotella, and Bacillus. Two groups were compared:
- Probiotic
group: participants
(animals or humans) received probiotics such as Lactobacillus or Bifidobacterium
for several weeks.
- Control
group: this group
received no probiotics (placebo or no treatment).
In animals, probiotics demonstrated
strong
immunomodulatory and anti-inflammatory effects. Their administration led to a
marked decrease in pro-inflammatory cytokines such as interferon gamma, tumor
necrosis factor alpha, and interleukin 17. At the same time, a
significant
increase in interleukin 10—a major anti-inflammatory cytokine—was observed in
several studies. Clinically, treated animals showed significantly reduced
symptom scores compared to control groups, indicating a
reduction in disease
severity. From an immunological standpoint, probiotics also helped
restore the
T-cell balance and
increase the proportion of regulatory T cells (Tregs), known
for their role in immune tolerance.
In humans, results pointed in the same
direction. The trials showed a
reduction in EDSS scores, an indicator of
MS-related neurological disability progression. A
decrease in pro-inflammatory
cytokine levels was reported, along with favorable changes in gut microbiota
composition. These findings suggest a
potential effect of probiotics on the
inflammatory environment and the gut-brain axis in patients with MS.
Bacteria full of promise
Multiple sclerosis is an
autoimmune disease of
the central nervous system marked by
chronic inflammation and
progressive
demyelination, often resulting in severe neurological disabilities. One of the
key mechanisms of the disease is
immune system dysregulation, notably an
overactivation of Th1 and Th17 lymphocytes. By targeting this imbalance,
probiotics—through their ability to modulate immunity and restore microbiota
composition—may offer a
complementary, natural, and non-invasive therapeutic
strategy in the treatment of MS.
This is precisely what the study aimed to
explore: to assess the potential effectiveness of probiotics in reducing the
progression of MS. The results are promising, especially in animals, where
probiotics reduced inflammation, improved clinical parameters, and promoted
activation of regulatory T cells. In humans, preliminary data suggest
beneficial effects on inflammatory markers and clinical severity.
Although probiotics represent a major avenue
for modulating immunity in MS patients, their actual efficacy has yet to be
confirmed. Larger, standardized clinical studies are still needed to validate
their role in therapeutic management.
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