2.10. - Introduction to Chronic Inflammation

Chronic inflammation is prolonged inflammation dominated by macrophages and lymphocytes, characterized by ongoing tissue damage and simultaneous attemps at repair.

chronic inflammation

prolonged inflammation dominated by macrophages and lymphocytes, characterized by ongoing tissue damage and simultaneous attempts at repair

• often results in angiogenesis and fibrosis

• three process occur together:

  1. persistent inflammation

  2. tissue destruction

  3. repair

settings of chronic inflammation

1. persistent infections → organisms difficult to eradicate

   • examples — tuberculosis, syphilis

2. immune-mediated inflammatory disease → excessive or inappropriate activation of immune system

   • autoimmune disorders and hypersensitivities

3. prolonged exposure to toxic substances

   • example — long-term exposure to silica may trigger persistent inflammation

4. 
   

chronic low-grade inflammation associated with disease

examples — Alzheimer disease, atherosclerosis, type 2 diabetes

• inflammatory tissue represents a small fraction of the body

• long-term inflammatory signaling may still have systemic consequences

dynamic nature of inflammation

transition state with mostly neutrophils (early), then increasing macrophages and lymphocytes (later)

• example— periodontitis

  • deeper chronic component → macrophages, lymphocytes, plasma cells

  • near bacterial biofilm → neutrophils