Probiotics

• Microbes


  Essential component of GIT (gastrointestinal tract)
• Microbes

  • Ten fold bacterial cells compared to somatic cells
  • Colonization occurs at perinatal period
  • Maternal environment
  • Stable intestinal microflora attained at post weaning / during early childhood
• Disturbance of resident microflora

  Deteriorates physiological functions
• Disturbance of resident microflora

  • Poor digestion / nutrient assimilation
  • Susceptibility to diarrhea causing pathogens
  • Immune dysfunction
• Intestinal Microflora

  • Do not cause pathogenesis & inflammation
  • Contribute to health maintenance
  • Forming barrier layer against colonization of pathogens
  • Aiding nutrients digestion & assimilation
  • Eliminating potentially damaging metabolites or toxins
  • Degrading potentially allergic food proteins
  • Regulating cholesterol & triglyceride uptake
  • Increasing vitamin biosynthesis
  • Providing signals that limit intestinal-inflammation

  
• Probiotics

  Friendly "bacteria" or "good bacteria"
• Probiotics (definition)

  Live microorganisms administered in adequate amounts which confer a beneficial health effect on the host
• Probiotics


  • Dietary supplements containing living microbes that are able to persist in GIT (colonization) and impart beneficial influence on host physiology
• Probiotic genera

  Lactobacillus<|>Bifidobacterium
• Probiotics

  Common fermentative microbes found in yogurt & cheese<|>Not replacement for indigenous (native / original) microflora<|>Required when normal microflora perturbed<|>Temporarily colonize and stabilize microflora composition<|>Augment the benefits of normal gut microflora
• Action of Probiotics

  1. Modify microflora to suppress pathogens

  2. Secrete antibacterial substances

  3. Compete with pathogens to prevent their adhesion to the intestine

  4. Compete for nutrients necessary for pathogen survival

  5. Antitoxin effect
• Effect of Probiotics on the Intestinal Epithelium

  • Promote tight contact between epithelial cells forming a functional barrier
  • Reducing the secretory and inflammatory consequences of bacterial infection
  • Enhancing the production of defensive molecules such as mucins
• Effect of Probiotics on Innate Immunity

  • Affect phagocytes at systemic and local GIT
  • Activate peritoneal macrophages by increasing phagocytic activity and lysosomal enzyme production
  • Enhance activity of peripheral blood derived monocytes & neutrophils
  • Increase NK cell activity against tumours (L. rhamnosus HN001)
• Effect of Probiotics on Adaptive Immunity

  • Increase systemic lymphocytes proliferation in response to T & B cell mitogens
  • Increase systemic lymphocytes to secrete T cell cytokines at in vitro
  • Increase CD4+ T cells in GALT (Peyer's Patch)
  • Elevate antibody production to parenterally and orally delivered foreign antigens
  • Increase mucosal density of IgA & IgM secreting plasma cells at lamina propria
  • Enhance pathogen specific antibody secretion against E. coli, Shigella sonnei & Salmonella thyphimurium
• Probiotics and Anti-tumour activity

  • L. casei Shirota reduced tumour formation of inoculated tumour cells in mouse model by increasing the number of lymphocytes, increasing secretion of IL-2 by lymphocytes, and enhancing NK cell activity
  • Decrease the incidents of tumour formation, when the mouse injected with carcinogens
• Probiotics & Immune Dysfunctions

  • Regulate allergic responses
  • In animal study, supplementation of L. casei Shirota & L. plantarum L-37 reduce allergic response by inducing secretion of IL-12
  • In human study, intake of probiotics supplemented yogurt for 1 year lower the circulating IgE and reduce nasal allergy in elderly