Inflammation. Part 1. Dr François Leclair Pr Christian Laboisse Pathology Department Nantes University Hospital JPEMS PDF Free Download

Inflammation Part 1 Dr François Leclair Pr Christian Laboisse Pathology Department Nantes University Hospital JPEMS 2014

Introduction

Two important points :

Two important points : 1 - Inflammation is a protective response intended to eliminate the initial cause of cell injury, necrotic cells and tissues resulting from the original insult.

Two important points : 1 - Inflammation is a protective response intended to eliminate the initial cause of cell injury, necrotic cells and tissues resulting from the original insult. Without inflammation, infections would go unchecked and wounds would never heal. 2 - But the inflammatory reaction and the subsequent repair process can cause considerable harm. Because it is capable of also injuring normal tissues especially when inflammation is : - very strong (e.g., when the infection is severe),

Two important points : 1 - Inflammation is a protective response intended to eliminate the initial cause of cell injury, necrotic cells and tissues resulting from the original insult. Without inflammation, infections would go unchecked and wounds would never heal. 2 - But the inflammatory reaction and the subsequent repair process can cause considerable harm. Because it s capable of also injuring normal tissues especially when inflammation is : - very strong (e.g., when the infection is severe), - prolonged (e.g., when the aggressor resists eradication) - inappropriate (e.g., when it is directed against self-antigens in autoimmune diseases.)

What original insult?

What original insult? -Infections (virus, bacterium, fungus)

What original insult? -Infections (virus, bacterium, fungus) -Mechanical trauma

What original insult? -Infections (virus, bacterium, fungus) -Mechanical trauma -Chemical trauma

What original insult? -Infections (virus, bacterium, fungus) -Mechanical trauma -Chemical trauma -Thermal, electrical injury

What original insult? -Infections (virus, bacterium, fungus) -Mechanical trauma -Chemical trauma -Thermal, electrical injury -Irradiation

What original insult? -Infections (virus, bacterium, fungus) -Mechanical trauma -Chemical trauma -Thermal, electrical injury -Irradiation - ( )

In medical terminology, the suffix «itis» refers to inflammation (e.g., appendicitis, peritonitis, ) Inflammation is the main phenomenon in a lot of diseases (infections, autoimmune diseases, allergic diseases ) important to know few stuff about inflammation!

Inflammation only occurs in vascularised tissues. No vessels no inflammation (cornea, cartilage).

1 Acute inflammation 2 Chronic inflammation 3 Tissue repairing (scar)

I Acute inflammation Acute inflammation is rapid in onset and of short duration, lasting from a few minutes to as long as a few days, and is characterized by fluid and plasma protein exudation and a predominantly neutrophilic leukocyte accumulation.

Normal

Physiology of tissue perfusion - microcirculation La capillary wall is a semi-permeable membrane: allows a flux of water and electrolytes and does not allow HMW protein flux. The net flux is determined by two forces acting in opposite directions Hydrostatic pressure Protein oncotic pressure

Inflamed

Inflamed 1- First step: vascular response. increased blood flow: redness and warmth

Small blood vessels adjacent to area of injury get dilated with increased blood flow. The tissue is congestive.

Explains redness (erythema) and warmth.

Inflamed 1- First step: vascular response. Exudation = Leakage of plasma with proteins oedema. Two components: -increased hydrostatic pressure -Increased vascular permeability

oedema - role of endothelial cell activation «the endothelial inflammatory phenotype» Endothelial remodeling (flat -> tall) Increased junctional permeability: opening of gaps Expression of adhesion proteins: P- selectin

Oedema Exudation : passage of water with a lot of proteins through blood vessels. This liquid = «exudate = inflammatory oedema». Which proteins in that liquid? A lot, such as immunoglobulins, complement, fibrinogen and fibrin (forming scab).

Explains swelling

Inflamed 2- Second step: cellular response. Cells (neutrophils +++) emigration

Cell emigration : 1- Margination : leukocytes accumulate along the vascular endothelial surface. 2- Leukocytes extravasation («diapedesis») out of the circulatory system (migration through inter-endothelial spaces). 3- Migration to the site of tissue damage, following a chemokines gradient. On the site of damage activated to perform their functions. Chemokines = proteins coming from the aggressor (e.g., bacterial product such as LPS) or from cells already on the site (macrophages+++).

Woman, 47 year old, abdominal pain. Fallopian tube resection :

Woman, 47 year old, abdominal pain. Fallopian tube resection : Vascular dilatation congestive tissue Oedema A fold filled with numerous neutrophils.

Woman, 47 year old, abdominal pain. Fallopian tube resection : Vascular dilation congestive tissue Oedema Acute salpingitis A fold filled with numerous neutrophils.

Few words about Neutrophils («PMN = PolyMorphoNuclear Neutrophils») Three-lobulated nucleus

Few words about Neutrophils («PMN = PolyMorphoNuclear Neutrophils») First cells to arrive on the site the cells of acute inflammation Role : bacterial killing by phagocytosis and by releasing enzymes. But : sligthly «stupid» cells that intervene even for a non-bacterial inflammation. e.g. : Chondrocalcinosis calcium pyrophosphate deposition disease.

PMN calcium pyrophosphate deposition

Let s sum up: Acute inflammation = 1 - Vascular step. Increased blood flow congestion. Exudation oedema + 2 - Cellular step (neutrophils +++)

Variations of acute inflammation : -Vasculo-exudative - Hemorrhagic - Suppurative - Necrotising inflammation

-sunburn -hives

-Quincke oedema

-pleural effusion

Variations of acute inflammation : -Vasculo-exudative - Hemorrhagic - Suppurative - Necrotising inflammation

-fulminans purpura

Variations of acute inflammation : -Vasculo-exudative - Hemorrhagic - Suppurative - Necrotising inflammation

Suppurative inflammation = numerous and quite exclusively neutrophils.

Suppurative inflammation = numerous and quite exclusively neutrophils. - clinically / gross examination : pus

Suppurative inflammation = numerous and quite exclusively neutrophils. - clinically / gross examination : pus - bacterial infection

Suppurative inflammation = numerous and quite exclusively neutrophils. - clinically / gross examination : pus - bacterial infection - 3 forms :

Suppurative inflammation = numerous and quite exclusively neutrophils. - clinically / gross examination : pus - bacterial infection - 3 forms :. Abscess (localised collection of pus)

Man, 54 year old, headache. Brain MRI :

Brain surgery : Normal brain Collection of neutrophils.

Liver abscess

Suppurative inflammation = numerous and quite exclusively neutrophils (dead or alive). - clinically / gross examination : pus - bacterial infection - 3 forms :. Abscess (localised collection of pus). Phlegmon (not collected amount of PMN) e.g. : complication of pharyngitis.

Suppurative inflammation = numerous and quite exclusively neutrophils. - clinically / gross examination : pus - bacterial infection - 3 forms :. Abscess (localised collection of pus). Phlegmon (not collected amount of PMN) e.g. : complication of pharyngitis.. Empyema (pus fills a hollow cavity) e.g. : subdural empyema.

Variations of acute inflammation : -Vasculo-exudative - Hemorrhagic - Suppurative - Necrotising inflammation

Outcomes of acute inflammation :

amage

amage Acute inflammation

Rapid destruction of the aggressor amage Acute inflammation

Rapid destruction of the aggressor Resorption of exudate and PMN amage Acute inflammation

Rapid destruction of the aggressor Resorption of exudate and PMN Resolution and return to initial aspect (e.g : minor burn) amage Acute inflammation

amage Rapid destruction of the aggressor Acute inflammation Resorption of exudate and PMN Organisation of exudate to fill loss of tissue Resolution and return to initial aspect (e.g : minor burn)

Fibrin (from exudate) Pleura Scar Lung parenchyma Organized pleuritis

amage Rapid destruction of the aggressor Acute inflammation Resorption of exudate and PMN Organisation of exudate to fill loss of tissue Resolution and return to initial aspect (e.g : minor burn) Scar (e.g : organised pleuritis) Incomplete destruction of the aggressor

Chemical mediators of inflammation. Mediators are proteins produced locally by inflammatory cells at the site of inflammation, or they are synthesized by the liver and circulate in the plasma. They have a responsibility in all the events of inflammation. They allow inflammatory cells to get activated or they may have opposing effects, thus serving to control the response. There are dozens of mediators

Few mediators to know : Histamine, bradykinin : involved in allergic phenomenons. Prostaglandins and Leukotrienes targets of anti-inflammatory drugs. Complement Coagulation factors

Inflammation Part 2 Dr François Leclair Pr Christian Laboisse Pathology Department Nantes University Hospital JPEMS 2014

II - Chronic inflammation Chronic inflammation may be more insidious, is of longer duration (days to years), and is typified by influx of lymphocytes and macrophages with associated vascular proliferation and fibrosis (scarring). Histologically, it starts when mononucleated cells (with a non-lobulated nucleus) arrive on the site.

Chronic inflammation : only a cellular response.

Chronic inflammation : only a cellular response. Wich cells?

Chronic inflammation : only a cellular response. Wich cells? - Macrophages

Chronic inflammation : only a cellular response. Wich cells? - Macrophages - Lymphocytes / Plasma cells

Chronic inflammation : only a cellular response. Wich cells? - Macrophages - Lymphocytes / Plasma cells - Eosinophils

Chronic inflammation : only a cellular response. Wich cells? - Macrophages - Lymphocytes / Plasma cells - Eosinophils - Mast cells

Macrophages Large nucleus Cytoplasm : numerous vacuoles of phagocytosis.

Macrophages Macrophages are normally diffusely scattered in most connective tissues, and are also found in organs (= specialized macrophages) :

- Kupffer cells in the liver -

- Osteoclasts in the bones -

- Alveolar macrophages in the lungs -

Macrophages Macrophages are normally diffusely scattered in most connective tissues, and are also found in organs (= specialized macrophages). Inflammation influx of macrophages coming from blood (margination, leukocytes extravasation, migration). When in the blood = «monocytes» when in tissues = «macrophages»

Enzymes Macrophages: secretory functions Protease Elastase Collagenase Plasminogen activator Acid hydrolases Phosphatases Lipase ROS Complement fractions Cytokines chemokines: Il-1, TNF inos Growth factors: PDGF TGFbeta

Activated macrophages: additional functions: link between innate and adaptive immunity (T cells) and repair

Morphological plasticity of macrophages Epithelioid cells Multinucleated giant cells

Chronic inflammation : a cellular response. Wich cells? - Macrophages - Lymphocytes / Plasma cells - Eosinophils - Mast cells

Lymphocytes Round nucleus. Cytoplasm hardly seen. When B lymphocytes differenciated = plasma cells

Lymphocytes B and T cells.

Lymphocytes B and T cells. intervene when it s an adaptative response (immune response, cellular or with antibodies) but also, for unknown reason, in a non-immune response. In any chronic inflammation! Coming from blood flow like the other leukocytes (margination, leukocytes extravasation, migration).

To fight against pathogen organisms, our body has 3 lines of defense : 1. First Line of Defense: Non-specific epithelial barriers which restrict entry of pathogen. Skin and mucosal surfaces (respiratory, gastrointestinal, urinary and reproductive tract) = physical, chemical and biological barriers 2. Second Line of Defense: Innate non-specific local immune response against pathogens that cross the epithelial barrier. PMN, macrophages, lymphocytes, they defend the host from infection by other organisms in a non-specific manner and does not confer long-lasting or protective immunity to the host. 3. Third line of defense: Antigen-specific immune responses, specifically target and attack invaders that get pass first two lines of defense = adaptive immune response (antibodies, lymphocytes) that recognize and remember specific pathogens.

Woman, 32 year old, abdominal pain.

Woman, 32 year old, abdominal pain. Fallopian tube :

lymphocytes plasma cells macrophages

lymphocytes plasma cells Chronic salpingitis. macrophages

Chronic inflammation : no vascular step, only a cellular response. Wich cells? - Macrophages - Lymphocytes / Plasma cells - Eosinophils - Mast cells

Eosinophils (PolyMorphoNuclear Eosinophils) important role in parasitic response.

Chronic inflammation : no vascular step, only a cellular response. Wich cells? - Macrophages - Lymphocytes / Plasma cells - Eosinophils - Mast cells

Mast cells important role in allergic response, by releasing histamine (among other molecules)

All these inflammatory cells come from bone marrow.

So far, we are able to say : «inflammation («itis») or not and acute and/or chronic».

So far, we are able to say : «inflammation («itis») or not and acute and/or chronic». But we can t determine the origin of this inflammation.

So far, we are able to say : «inflammation («itis») or not and acute and/or chronic». But we can t determine the origin of this inflammation. = «Non-specific inflammation».

lymphocytes plasma cells Non-specific chronic salpingitis. macrophages

So far, we are able to say : «inflammation («itis») or not and acute and/or chronic». But we can t determine the origin of this inflammation. = «Non-specific inflammation». On the contrary, when we observe inflammatory cells but also some characteristics that can allow us to come close the cause or even to make a precise diagnosis.

The cause can be determined : either because the inflammation is «particular». or because we can see the pathogen. or both

the inflammation is particular

the inflammation is particular Most typical example : granulomatous inflammation.

the inflammation is particular Most typical example : granulomatous inflammation. Woman, 41 year old, coughing. Bronchus biopsy :

Lymphocytes lymphocytes Epithelioid macrophages macrophages Multinucleate giant cell GRANULOMATOUS INFLAMMATION

Interesting because finite quantity of etiologies!

Interesting because finite quantity of etiologies! - Certain bacterium : Typical Mycobacteria (tuberculosis), atypical mycobacteria, cat scratch disease, donovanosis, leprosy, importance of microbiology analysis - Foreign body (suture, metal particule, ) - Diseases of unknown origin : crohn disease, sarcoidosis, some autoimmune diseases (Wegener, Churg and Strauss, )

we can see the pathogen.

we can see the pathogen. Examples

Man, 79 year old, diarrhea. Large bowel biopsy :

lymphocytes plasmocytes viral nuclear inclusion Specific inflammation caused by Cytomegalovirus (CMV) infection

Young boy, 6 year old, abdominal pain. Appendicectomy :

lymphocytes, macrophages, PMN pinworm Specific inflammation caused by pinworm

Women, 41 year old, from Martinique. Abdominal pain. Gastric biopsy :

Few lymphocytes strongyloïdosis Specific inflammation caused by strongyloïdosis

Man, 50 year old. Abdominal pain. Gastric biopsy :

Normal gastric antrum

May-Grunwald-Giemsa stain. (Magnification x 400).

Helicobacter pylori May-Grunwald-Giemsa stain. (Magnification x 400).

Helicobacter pylori Chronic gastritis due to Helicobacter pylori May-Grunwald-Giemsa stain. (Magnification x 400).

Helicobacter pylori Gram negative bacterium. Adapted to live in association with surface epithelium beneath mucus barrier. Causes cell damage and inflammatory cell infiltration. In most countries the majority of adults are infected.

Inflammation Part 3 Dr François Leclair Pr Christian Laboisse Pathology Department Nantes University Hospital JPEMS 2014

III - Tissue repairing - Fibrosis - Scaring

III - Tissue repairing - Fibrosis - Scaring Follows a chronic inflammation (sometimes acute inflammation!) that has caused tissue destruction.

III - Tissue repairing - Fibrosis - Scaring Follow a chronic inflammation (sometimes acute inflammation!) that has caused tissue destruction. Repairing cannot be made only with the original cells.

III - Tissue repairing - Fibrosis - Scaring Follow a chronic inflammation (sometimes acute inflammation!) that has caused tissue destruction. Repairing cannot be made only with the original cells. 2 phenomenons involved : cells. 1- Regeneration = replacement of damaged cells by same 2- Fibrogenesis = replacement of loss of substance by fibrosis

Repair starts with vascular proliferation and fibroblasts proliferation (they synthesize collagen) = granulation tissue that fill the loss of tissue.

Repairement starts with vascular proliferation and fibroblasts proliferation (they synthesize collagen) = granulation tissue that fill the loss of tissue. # granulomatous inflammation

Surface : covered by debris and exudate (remains of an ulceration) Granulation tissue : very cellular and highly vascular area containing fibroblasts and inflammatory cells. Granulation tissue

Numerous capillaries Fibroblasts, PMN, lymphocytes, macrophages Granulation tissue (high power view)

Then, this granulation tissue endergoes reshaping to become a scar.

Epidermis Dermis Sebaceous and pilar appendages - Normal skin -

Scar in the dermis

-Normal heart -

Scar Loss of function

Pathology :

Pathology : Delay in / absence of scarring. Cause: persistence of pathogen, bad vasculature, persistence of foreign body, mechanical factor (mobilisation of the wound),

Pathology : Delay in / absence of scarring. Cause: persistence of pathogen, bad vasculature, persistence of foreign body, mechanical factor (mobilisation of the wound), Excessive scar formation :

Pathology : Delay in / absence of scarring. Cause: persistence of pathogen, bad vasculature, persistence of foreign body, mechanical factor (mobilisation of the wound), Excessive scar formation : - hypertrophic scar (does not expand beyond the boundaries of the initial injury and may undergo partial spontaneous resolution). -keloid(overgrowth of dense fibrous tissue extends beyond the borders of the original wound, does not usually regress spontaneously and tends to recur after excision).

Keloid formation is a result of excessive collagen deposition during wound healing. Epidermis and underlying dermis are displaced upward by a fibrous nodule.

Epidermis Interlacing broad bands of collagen

Chronic inflammation

mild Chronic inflammation

mild Resolution and return to initial aspect (e.g : cut) Chronic inflammation

mild Resolution and return to initial aspect (e.g : cut) Chronic inflammation Severe with tissue destruction

mild Resolution and return to initial aspect (e.g : cut) Chronic inflammation Severe with tissue destruction Granulation tissue

mild Resolution and return to initial aspect (e.g : cut) Chronic inflammation Severe with tissue destruction Granulation tissue Scar (loss of function) (e.g : myocardial infarction)

mild Resolution and return to initial aspect (e.g : cut) Chronic inflammation Severe with tissue destruction Granulation tissue Scar (loss of function) (e.g : myocardial infarction) Pathologic scar (delay, absence, hypertrophy, keloid, retraction)

So chronic inflammation can follow acute inflammation

So chronic inflammation can follow acute inflammation But can these 2 types of inflammation occur at the same time?

But how?

1- Because of an overlap : Vasculo-exsudative step Cellular step Neutrophils Mononucleate cells Acute inflammation Chronic inflammation

1- Because acute inflammation can aggravate a chronic inflammation :

1- Because acute inflammation can aggravate a chronic inflammation : Macrophages infiltrate Congestion Oedema

1- Because acute inflammation can aggravate a chronic inflammation : Macrophages infiltrate Congestion Oedema Multiple acute inflammation episodes have led to chronic cholecystitis. Here it s a new acute inflammation episode.

mild Resolution and return to initial aspect (e.g : cut) Chronic inflammation Cancer (e.g : gastric cancer after long history of chronic gastritis) Severe with tissue destruction Granulation tissue Scar (loss of function) (e.g : myocardial infarction) Pathologic scar (delay, absence, hypertrophy, keloid, retraction)

mild Resolution and return to initial aspect (e.g : cut) Chronic inflammation Metaplasia Cancer (e.g : gastric cancer after long history of chronic gastritis) Severe with tissue destruction Granulation tissue Scar (loss of function) (e.g : myocardial infarction) Pathologic scar (delay, absence, hypertrophy, keloid, retraction)

mild Resolution and return to initial aspect (e.g : cut) Chronic inflammation Metaplasia Dysplasia Cancer (e.g : gastric cancer after long history of chronic gastritis) Severe with tissue destruction Granulation tissue Scar (loss of function) (e.g : myocardial infarction) Pathologic scar (delay, absence, hypertrophy, keloid, retraction)

Consequence of chronic inflammation on epithelia : Metaplasia

Definition Metaplasia: replacement of a differentiated cell type by another mature normal differentiated cell type. Usually of the same class : - epithelial cell to epithelial cell, - connective tissue cell to another connective tissue cell An example of chronic cellular adaptation to chronic or repeated low-level injury (chronic infection or noninfectious injury). Different from dysplasia : - Metaplasia : no atypical cells - Dysplasia : atypical cells.

Some examples

Conversion of the normal ciliated bronchial epithelium to stratified squamous epithelium following tobacco smoking :

Conversion of the normal ciliated bronchial epithelium to stratified squamous epithelium following tobacco smoking : More resistant to cigarette smoke.

Metaplasia of oesophageal stratified squamous epithelium to glandular cells due to chronic gastric reflux : «Barrett metaplasia»

Metaplasia of oesophageal stratified squamous epithelium to glandular cells due to chronic gastric reflux : «Barrett metaplasia» Gastric metaplasia Normal squamous epithelium

What is the significance of metaplasia? A potentially reversible change if the cause is withdrawn. Connective tissue metaplasia is of little to no clinical consequence (an incidental finding) The significance of Epithelial metaplasia depends on the organ. Squamous metaplasia of the uterine cervix is per se an adaptive mechanism and is a physiological process. In other organs, it may lead to Dysplasia and then malignant neoplasia.

Chronic inflammation

Chronic inflammation Metaplasia

Chronic inflammation Metaplasia Dysplasia

Chronic inflammation Metaplasia Dysplasia Cancer

Chronic inflammation Metaplasia Dysplasia Cancer Sequence of cancer development in chronic inflammatory mucosa.

Chronic inflammation Metaplasia Dysplasia Cancer Sequence of cancer development in gastric chronic inflammatory mucosa.

Chronic inflammation Metaplasia Dysplasia Cancer Sequence of cancer development in chronic inflammatory mucosa.

Remember this chronic gastritis due to Helicobacter pylori.

Intestinal metaplasia in chronic gastritis Goblet cells intestinal metaplasia

Gastric adenocarcinoma Arise on background of chronic gastritis, intestinal metaplasia, dysplasia

Test yourself (understanding the pathological diagnosis)

Biopsy of a rapidly growing breast «lump» in a 39y old patient

The question is: tumor of inflammation?

Biopsy of a breast «lump»

Morphological interpretation Giant cells Optically empty vacuoles

Background information for the interpretation Optically «transparent» vacuoles (arrow) are present in a variety of breast carcinomas, the so-called «signet ring cell carcinomas».

Background information Optically «transparent» vacuoles (arrow) are present in a variety of breast carcinomas, the so-called «signet ring cell carcinomas». - Histochemistry using alcian blue: the vacuoles stain blue - Immunohistochemistry : the vacuolar cells are immunostained with an anti-cytokeratin antibody.

Bakground information: Cytokeratins form a variety of «intermediate filaments» specific of epithelial cells

In our case: Alcian blue staining: negative Cytokeratin immunohistochemistry: negative. What do you propose?

Giant cells The vacuolar cells have a phagocytic function: they are macrophages Inflammatory lesion: granuloma (localized accumulation of macrophages)

Is it a «specific granuloma»? the presence of «giant cells» in addition to macrophages favors the diagnosis of «specific granuloma», variety «foreign body granuloma» the determination of the nature of the «transparent material» ingested by the macrophages is the key to the «specificity»

The patient s story History of bilateral silicone implants

Final diagnosis Giant cells Round transparent vacuoles (phagocytized silicone) Dg: foreign body granuloma to silicone (leaking silicone implant)

Inflammation. Part 1. Dr François Leclair Pr Christian Laboisse Pathology Department Nantes University Hospital JPEMS 2014