Question

Comment on the results of each of these recent experiments in light of the Old Friends hypothesis:

a) A small group of Finnish children were matched at birth by age and relevant genotype, then followed to see if any developed autoantibodies typical of type I diabetes. Compared to matched healthy controls, the children who would develop T1D had markedly different gut microbiomes. Relative to those of matched healthy controls, rheir microbiomes were less diverse, more unstable, and became increasingly dominated by Bacteriodetes. In contrast, the healthy children increased their population of Firmicutes relative to Bacteriodetes as they got older.

b) Mice treated from birth with broad spectrum antibiotics and tested later in life had lower than normal gut expression of microbial pattern recognition molecules like TLR2, 4, and 5.

Answer 1

a)

• T1D and fat metabolism is controlled by bacteria in the gut.
• Firmicutes are bacteria that are present when the body takes more fat diet and it cause increase in fat metabolism.
• If firmicutes are p[resent in high numbers then Bacteriodetes will gets reduced.
• Bacteriotedes are produced only when the body loses its weight and Firmicutes population decreases.
• Moreover, the Bacteriotedes alter the mucosal lining such that the immunity of the host is reduced . It also makes the pathogen more susceptile to the environment and thus the microbiome is not so diverse in the T1D patients.
• Healthy children have increased body weight and thus they have high fat diet , so the Firmicutes population gets increased and Bacteriotedes population is reduced.

b)

• Broad spectrum antibiotics alters the regulatory T cells in the gut. Thus production of T cell receptors are also altered.
• The antibiotics kill the commensal bacteria and thus the environment of the gut is altered . This makes the alteration in regulatory T cells and thus its receptors production is affected.
• That is why the TLR 2,4 and 5 are less in mice treated with broad spectrum antibiotics.