Chronic Inflammation Flashcards
prolonged duration (weeks to months to years) in which active inflammation, tissue injury, and healing proceed simultaneously. ?
Chronic inflammation
Chronic inflammation Characterized by ?
- Infiltration with macrophages, lymphocytes, and
plasma cells
2.Tissue destruction, induced by the products of the
inflammatory cells. - Repair, involving new vessel proliferation (angiogenesis)
and fibrosis.
Causes of chronic inflammation?
- Primary chronic inflammation 2. Progression from acute inflammation: • The persistence of the injurious agent or • Interference with the normal process of
healing.
Causes of Primary Chronic inflammation ( i.e no initial phase of acute inflammation)?
- Persistent infections by
microbes that are difficult to
eradicate. - 2- Immune-mediated
- 3- Prolonged exposure to
potentially toxic agents.
Eg:
Chronic Inflammatory Cells
Macrophages, 2.Lymphocytes, 3.Eosinophils
Two major pathways of macrophage activation ?
- Classical pathway 2. Alternative pathway
Classical macrophage activation induced by
Induced by: 1. microbial products such as endotoxin, 2. T cell–derived signals, the cytokine IFN-γ, and 3. by foreign substances including crystals and particulate matter.
Classically activated macrophages produce : ?
- lysosomal enzymes, 2. NO, and 3. ROS,
Classical macrophage activation
Work on ?
Ros and no and lysosome = Phagocytosis and killing of many bacteria / inflammation = iil 1 12 23 Chemokines
All of which enhance their ability to kill ingested organisms, and
secrete cytokines that stimulate inflammation.
• These macrophages are important in host defense against ingested
microbes and in many chronic inflammatory reactions.
Alternative macrophage activation
Induced by?
Cytokines (IL-4 and IL-13, produced by T lymphocytes and other
cells, including mast cells and eosinophils.
Alternative macrophage activation
Role ?
tissue repair. They secrete growth factors that promote 1. angiogenesis, 2. activate fibroblasts and 3. stimulate collagen synthesis.
Il 10 =anti inflammatory
induce macrophages to fuse into large,
multinucleate giant cells?
IFN-γ
Initiate the process of tissue repair and are involved in scar
formation and fibrosis.
Role of ?
Macrophages
Display antigens to T lymphocytes and respond to signals from T
cells.
Role of ?
Macrophages
2.Lymphocytes properties?
Two types: T and B lymphocytes which migrate into
inflammatory sites by action of chemokines. Lymphocytes interact with macrophages to kill the organism .
3.Eosinophils properties?
Found in inflammatory sites around parasitic infections or as
part of immune reactions associated with allergies.
The commonest appearances of chronic inflammation are?
- Chronic ulcer, 2. Chronic abscess cavity, 3. Thickening of the wall of a hollow viscus by fibrous tissue 4. Granulomatous inflammation,
granuloma microscopically characterized by ?
aggregation of
macrophages that are transformed into epithelium-like cell
(epithelioid appearance) surrounded by a collar of mononuclear
leukocytes, principally lymphocytes and occasionally plasma
cells.
• Older granulomas develop an enclosing rim of fibroblasts and
connective tissue .
Granulomas can form under three settings:
?
1- With persistent T-cell responses to certain microbes (such as Mycobacterium tuberculosis, T. pallidum, or fungi), in which T cell–derived cytokines are responsible for chronic macrophage activation.
2- In a disease of unknown etiology called sarcoidosis
3- Granulomas may develop in some immune mediated inflammatory diseases, notably Crohn disease. 4- They develop in response to relatively inert foreign bodies (e.g., suture or splinter), forming so-called foreign body granulomas
tubercle bacillus grossly ?
granular, cheesy appearance called caseous necrosis.
tubercle bacillus microscopy?
Necrotic material appears as amorphous, structure less,
granular debris. • Focus of activated macrophages (epithelioid cells),
rimmed by fibroblasts, lymphocytes, histiocytes,
occasional Langhans giant cells. • Central necrosis with amorphous granular debris; acid-
fast bacilli • (ziehl Neelsen stain for acid fast bacilli)
Types of giant cells ?
= Langhans’ giant cells Langhans’ giant cells have a horseshoe arrangement of peripheral nuclei at one pole of the cell and are characteristically seen in tuberculosis, although they may be seen in other granulomatous conditions
= Foreign body giant cells Foreign body giant cells’ are large cells with nuclei randomly scattered throughout their cytoplasm. They are characteristically seen in relation to particulate foreign body material.
most important
mediators of the acute-phase reaction ?
cytokines TNF, IL-1, and IL-6 = plasma proteins
The acute-phase response consists of ?
- Fever:
- Elevated plasma levels of acute-phase proteins:
- Leukocytosis
- Other manifestations of the acute-phase response include:
- Chronic inflammation
- In severe bacterial infections (sepsis),
High levels of TNF cause ?
disseminated intravascular
coagulation (DIC), hypoglycemia, and hypotensive shock.
wasting
syndrome called cachexia, which is mainly the result of TNF
-mediated appetite suppression and mobilization of fat stores.?
5.Chronic inflammation is
