Immunological changes induced by
traumatic brain injury predispose patients to infections, sepsis, and other
adverse effects. Brain injury induces critical changes that compromise the
immune system of the patient. Suppression of immunity sets in early and may
last for weeks.
function of immune mechanisms requires a balance between T-helper type 1 (Th1)
and T-helper type 2 (Th2) cytokines. Cytokines are protein molecules produced
by cells of the immune system that serve to regulate immunity.
brain injury alters the immune response shifting it from Th1 to Th2 response.
The resulting Th1/Th2 imbalance makes patients susceptible to infections,
sepsis and other adverse effects. Traumatic brain injury puts patients at
increased risk of ventilator-associated pneumonia (VAP); the incidence of VAP
can reach 60% in this group of patients.
studies in mice and patients had shown protective effects of probiotic therapy
in allergy. Probiotic preparations contain beneficial bacteria and are most
commonly used in the treatment of conditions like infectious diarrhea,
antibiotic-associated diarrhea, and necrotizing enterocolitis. The protective
digestive flora in human gut commonly disappears following various diseases or
treatment with antibiotics, and probiotics help to replace this flora.
restore the healthy gut bacteria. Researchers have shown that probiotics reduce the growth of
potentially disease causing microbes, improve gut mucosal barrier function, and
modulate local and systemic immune functions. However, the use of probiotics in
critically ill patients has been a subject of controversy.
A recent study evaluated
the effects of probiotics in critically ill patients down with traumatic brain
injury. Probiotics used in the study included Lactobacillus bulgaricus,
Bifidobacterium longum and Streptococcus thermophilus. Bifidobacteria are the commonest inhabitants
of healthy human gut.
When administered to critically ill
patients suffering traumatic brain injury, probiotics boosted cellular immunity
by correcting the Th1/Th2 imbalance. Th2 response switched
back to the required Th1 response. By enhancing the immune system, probiotics
decrease infections. The occurrence of hospital-acquired infections (nosocomial
infections) can be reduced by the use of probiotics. It is true that the recent
study of probiotics was not devoid of limitations, but the results support
prophylactic administration of probiotics in traumatic brain injury patients.
The findings of the new study
support the safe use of probiotics in critically ill patients.
It is worth noting that researchers did not find any adverse effects linked to
Reference: Effects of probiotics on serum levels of
Th1/Th2-cytokine and clinical outcomes in severe traumatic brain-injured
patients: a prospective randomized pilot study; Min Tan et al; Critical Care