Lect 7 - Chronic Inflammation Flashcards
what changes in acute inflammation to make it chronic?
Most common in supporative (pus forming) acute inflammation
Pus can form an abscess
If deep enough the walls thicken
Granulation and fibrous tissue
Recurrent acute can lead to chronic e.g cholecystitis = gall bladder inflammation usually due to stones
what Morphological Features would you see in chronic inflammation?
Infiltration with mononuclear cells (macrophages, lymphocytes, plasma cells)
Tissue destruction
Healing by fibrosis
on a cellular level, what would be observed in chronic inflammation?
Cellular infiltrate of lymphocytes, plasma cells and macrophages
Production of new fibrous tissue from granulation tissue
how do macrophages behave in a site of chronic inflammation?
Increase inflammation, stimulate immune system
Macrophages already at sight of damage release cytokines which signal to monocytes
Monocytes enter damaged tissue from endothelium of blood vessel (leukocyte extravasion) = RECRUITMENT
Macrophages PROLIFERATE locally in damaged tissue
IMMOBILISATION of macrophages within tissue
macrophages also have a couple of other important functions in chronic inflammation. what are they?
They cause the fibrosis by releasing growth factors and other molecules.
induse angiogensis factors for blood vessel formation in granulation tissue.
They can also hold and contain viable organisms if they cannot kill them (granulomas) – examples include M. tuberculosis and M. leprae.
what is granulation tissue?
GRANULATION TISSUE is new connective tissue and blood vessels that form on the surface of a wound during healing. Grows up from baase of wound.
Appears light red or dark pink due to capillaries, painless if healthy, soft and moist.
what is fibrosis?
Formation of excess fibrous connective during repair of damaged tissue
Scarring
Called fibroma if arises from 1 cell line
Macrophage induced laying down of connective tissue inc collagen
what type of cell forms in granulomatous inflammation?
Histiocytic giant cells can form where material is indigestible to macrophages e.g tubercle bacilli which have cell walls resistant to macrophages
They’re multinucleate giant cells. May have >100 nuclei.
Develop when 2+ macrophages try to engulf the same particle.
No known function. Not phagocytic.
Given different names according to appearance
what dies eases lead to Granulomatous disease?
Bacterial = TB, leprosy Parasitic = schistosomiasis Fungal = cryptococcus Synthetic materials = silicosis Unknown = Sarcoidosis, crohn’s disease.
what messengers are particularly important in formation and function of granuloma
TNF alpha and INF gamma
what layers of a TB granuloma are there starting from the middle?
- Caseous necrosis
- Epithelioid macrophages and langhans-type giant cells
- lympocytes and plasma cells
- all encased with fibroblasts making a collagen structure to keep it all in.
BASICALLY BAD STUFF ->MACROPHAGES+GIANTS -> LYMPHOCYTES -> COLLAGEN COAT
what makes langhans-type giant cells?
lots of Epithelioid macrophages together
give some examples of diseases in which chronic inflammatory processes have a role
Chronic inflammation is involved in cardiovascular system response to MI – myocardial fibrosis
Inflammation is involved in atheroma formation – macrophages adhere to epithelium and recruit other cells, process lipids that accumulate in plaques
In MS inflammation; plasma cells and T lymphocytes are seen in white matter where macrophages break down myelin
