What is inflammation?

1
(No Transcript)
2
(No Transcript)
3

• What is inflammation?
• What are the cardinal signs?
• What are the vascular changes in Acute
  Inflammation?
• What are the cellular changes in Acute
  Inflammation?

4
INFLAMMATION

• It is a complex reaction to injurious agents such
  as microbes and damaged, usually necrotic, cells
  that consist of
• Vascular responses,
• Migration and activation of leukocytes and
• Systemic reactions
• the reaction of a tissue and its
  microcirculation to injury

5
TISSUE INJURY

• Physical
• Chemical
• Biological
• Ischaemia
• Neoplasm

6
Inflammation and repair are fundamentally
protective but may be potentially harmful
7
TYPES

• Acute Inflammation of short duration, edema and
  leukocyte emigration esp. Neutrophils
• Chronic Inflammation of longer duration,
  Lymphocytes, Macrophages, Blood vessel
  proliferation, Fibrosis and Tissue necrosis

8
COMPONENTS

• Fluid Plasma proteins
• Cells
• Circulating N, L, M, E, B
• Connective tissue Mast cells, Fibroblasts,
  Macrophages
• Extracellular matrix
• Structural Collagen, Elastin
• Adh Glycoproteins Fibronectin, Laminin,
  Tenascin etc
• Proteoglycans

9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
SIGNS

• Rubor (redness)
• Tumor (swelling)
• Calor (heat)
• Dolor (pain)
• 
  -Cornelius Celsus
• Functio laesa (loss of function)
• -
  Rudolf Virchow

14
(No Transcript)
15
(No Transcript)
16
(No Transcript)
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
Ilya Mechnikov
( Elie Metchnikoff ) and the Phagocyte
Cells

• In 1882, the Russian scientist Ilya Mechnikov was
  working in Messina, Italy, studying the larvae of
  the sea star. When he inserted a thorn into a
  larva, something weird happened. Mechnikov
  noticed strange cells gathering at the point of
  insertion. The cells surrounded the thorn, eating
  any foreign substances that entered through the
  ruptured skin. Mechnikov was thrilled. He decided
  to name these new cells phagocytes from the Greek
  words meaning "devouring cells."

21
Paul Ehrlich and the Side-chain Theory

• At the end of the nineteenth century, the German
  scientist Paul Ehrlich developed the "side-chain
  theory" to explain immunity and how antibodies
  were formed. Although we now know that some of
  his ideas were incorrect, this theory allowed him
  to accomplish important work and provided the
  groundwork for later researchers in this field.
• Ehrlich argued that all cells have a wide variety
  of special receptors that he called side-chains.
  He thought that these receptors worked like
  gatekeepers or locks for the cell. Each
  receptor/side-chain had a unique structure, and
  only substances matching this structure were
  allowed to enter the cell.
• The side-chain receptors primary function was to
  absorb nutrients for the cell. Unfortunately, the
  receptors also allowed many toxic substances to
  enter. According to Ehrlich, the body defended
  itself against these toxins in the following way
  When a cell was attacked by a toxin, it started
  to produce excess side-chains matching the toxin.
  These excess side-chains then were released,
  flooding the body and neutralizing free toxins by
  attaching to them. The toxin was wiped out and
  remaining healthy cells protected.

22
(No Transcript)
23
Historical CommentaryNature Immunology 9, 705 -
712 (2008) doi10.1038/ni0708-705Immunology's
foundation the 100-year anniversary of the Nobel
Prize to Paul Ehrlich and Elie MetchnikoffStefan
H E KaufmannAbstractOne hundred years ago the
birth of immunology was made official by the
Nobel Prize award to Elie Metchnikoff and Paul
Ehrlich. Metchnikoff discovered phagocytosis by
macrophages and microphages as a critical
host-defense mechanism and thus is considered the
father of cellular innate immunity. Ehrlich
described the side-chain theory of antibody
formation and the mechanisms of how antibodies
neutralize toxins and induce bacterial lysis with
the help of complement and thus is considered one
of the fathers of humoral adaptive immunity.
Despite many discordant discussions in the
initial phase after these discoveries, innate and
adaptive responses are now known to be
complementary partners in producing robust
immunity.
24
(No Transcript)
25
(No Transcript)
26
ACUTE INFLAMMATION

• Changes in vascular caliber
• Changes in vascular structure
• Emigration of leukocytes, accumulation at site of
  injury and their activation

27
Changes in Vascular Flow and Calibre

• Vasodilatation and increased blood flow
• First involves arterioles

28
Increased Vascular permeability

• Leads to escape of protein rich fluid into the
  extravascular tissue
• Endothelial changes lead to increased permeability

29
(No Transcript)
30
(No Transcript)
31
(No Transcript)
32
(No Transcript)
33
(No Transcript)
34
(No Transcript)
35
(No Transcript)
36
(No Transcript)
37
(No Transcript)
38
(No Transcript)
39
(No Transcript)
40
(No Transcript)
41
(No Transcript)
42
(No Transcript)
43
The series of events are

• Vasodilation leads to greater blood flow to the
  area of inflammation, resulting in redness and
  heat.
• Vascular permeability endothelial cells become
  "leaky" from either direct endothelial cell
  injury or via chemical mediators.
• Exudation fluid, proteins, red blood cells, and
  white blood cells escape from the intravascular
  space
• Vascular stasis slowing of the blood in the
  bloodstream

44

• An exudate is an inflammatory extravascular fluid
  that has a high protein concentration, cellular
  debris, and a specific gravity above 1.020
• A transudate is a fluid with low protein content
  (most of which is albumin) and a specific gravity
  of less than 1.012

45
Pus, a purulent exudate, is an inflammatory
exudate rich in leukocytes (mostly neutrophils),
the debris of dead cells and, in many cases,
microbes.