The document discusses the pathophysiology of the respiratory system. It begins with an overview of breathing and gas exchange. It then covers anatomy and functions of the airways, lungs, and alveoli. Specific conditions like pneumonia, lung cancer, pleural effusion, and cystic fibrosis are examined. Diagnostic tools like bronchoscopy, thoracentesis, and genetic testing are also summarized. The roles of cells like pneumocytes and molecular components like surfactant and the CFTR protein are defined.

1. PHATHOPHYSIOLOGY

2. BREATHING
• The main function is to oxygenate the
hemoglobin and remove carbon dioxide from the
blood.
• Into the pulmonary capillaries the venous blood
receives O2 and releases CO2 becoming arteriosus.

3. O2
ATMOSPHERIC
AIR
CO2
TISSUESLUNGS

4. ANATOMY

5. ANATOMY

6. PLEURAL ANATOMY

7. AIRWAYS ANATOMY

8. In the conduction system the inspired air is heated, humidified and purified.
This latter function is of fundamental importance; particles having a diameter greater than
5 mm are stopped before reaching the alveoli, retained by mucus and ejected toward the
pharynx by mucociliary transport.
Particulate
Mucociliary transport is the mechanism by which the airways clears itself of secretions and
trapped particulates. The two major components of this system are the mucous blanket and the
ciliated epithelial cells.
Mucus
Cilia
Goblet cells
Columnar cells
Basement
membrane
AIRWAYS FUNCTIONS

11. Dead space is the volume of air which is inhaled that does not take part in the gas exchange,
either because it remains in the conducting airways, or reaches alveoli that are not perfused or
poorly perfused. In other words, not all the air in each breath is available for the exchange of
oxygen and carbon dioxide. Mammals breathe in and out of their lungs, wasting that part of
the inspiration which remains in the conducting airways where no gas exchange can occur.
CONDUCTING
ZONE
TRANSITIONALAL
ZONE
RESPIRATORY
ZONE
FUNCTIONAL ANATOMY

12. Alveolar-capillary units are the structures in which gas exchange occurs.
Lungs contain about 300 * 106 alveoli with a surface area for gas
exchange of about 140 m2. The alveoli consist of an epithelial layer and
extracellular matrix surrounded by capillaries. The alveoli contain some
collagen and elastic fibres.

13. Elastic fibres
Type II pneumocytes
Type I pneumocytes
Capillaries
Macrophages Endothelial cells
ALVEOLAR HYSTOLOGY
There are three major cell types in the alveolar wall (pneumocytes):
• Type I (Squamous Alveolar) cells that form the structure of an alveolar wall
• Type II (Great Alveolar) cells that secrete pulmonary surfactant to lower the surface tension of
water and allows the membrane to separate, therefore increasing its capability to exchange
gases. Surfactant is continuously released by exocytosis.
• Macrophages that destroy foreign material, such as bacteria.

15. Inhalation (breathing in) is an active movement due to diaphragm and other
respiratory muscles contraction. These contractions cause the thoracic cavity to
increase in volume, thus decreasing the pressures within the lung according to
Boyle’s law. Intrapleural and Alveolar Pressures are related because pleural
space is an enclosed space and its volume can not be modified. This negative
pressure within the lungs acts as a Pressure Gradient, thus pulling air into the
lungs. As air fills the lungs, the negative alveolar pressure moves back towards
atmospheric pressure, and air flow into the lungs slows down. In contrast,
expiration (breathing out) is usually a passive process due to the elastic recoil of
the lung tissue (rich in elastic fibers). During exercise or other conditions
requiring hyperventilation expiration becomes an active process due to
muscular activity.
BREATHING MECHANISM

18. PNEUMONIA
DEFINITION: Infection interesting the lung (alveoli, distal
airways and lung interstitium).
CLASSIFICATION:
Community acquired
Nosocomial

20. ETIOLOGY
• COMMUNITY ACQUIRED
– Streptococcus Pneumoniae
– Haemofilus Influenziae
– Stafilococcus Aureus
– Others (Mycoplasma, Clamidia, Legionella, etc.)
• HOSPITAL ACQUIRED
– Pseudomonas Aeruginosa
– Enterobacter
– Klebsiella Pneumoniae

21. CLINICAL PICTURE
• Fever
• Caugh without or with sputum
• Shortness of breath
• Chest pain (due to pleural involvment)
• Physical examination (rales due to secretions)
• Blood tests (inflammatory indexes, blood gases)
• X-ray

24. 4 MAIN HYSTOTYPES:
• NSLC (non-small lung cancer)
– Squamous cell carcinoma
– Adenocarcinoma
– Large cell anaplastic carcinoma
• Small cell anaplastic carcinoma
LUNG CANCER

26. Adenocarcinoma
in the upper lobe of the
left lung

27. Large cell anaplastic
carcinoma of the upper
lobe of the right lung
with extensive
involvement of hilar
and carinal nodes.

28. Small cell anaplastic
carcinoma of the
right lung with lung
metastases and
extensive hilar and
carinal nodes.
Squamous cell
carcinoma shows the
same growth pattern
but its evolution is
slower.

29. Cancers that can
metastatize the lung

30. PLEURAL EFFUSION
• TRANSUDATE: heart failure, hypoalbuminemia.
• EXUDATE: inflammatory fluid with high
concentration of protein, LDH and inflammatory cells
(lymphocytes, granulocytes, macrophages, red blood
cells or neoplastic cells). Causes: pleurisy,
pneumonia, pulmonary embolism, lung cancer and
pleural cancer.

32. THORACENTESIS
• Thoracentesis is a percutaneous procedure during which a
needle is inserted into the pleural space and pleural fluid is
removed through the needle
• Diagnostic thoracentesis refers to removal of a small volume
of pleural fluid for analysis,
• Therapeutic thoracentesis refers to removal of a large volume
(< 1L) of pleural fluid for relief of symptoms (.
Useful exams
• Cell count
• Biochemistry
• Culture
• Cytology

33. BRONCHOSCOPY
Bronchoscopy is the process of direct visualization of the tracheobronchial tree. Bronchoscopy
is now performed almost exclusively with flexible fiberoptic instruments.
The bronchoscopist is able to identify endobronchial pathology, including tumors, granulomas,
bronchitis, foreign bodies, and sites of bleeding.
Samples from airway lesions can be taken by several methods, including washing, brushing,
and biopsy.
Washing involves instillation of sterile saline through a channel of the bronchoscope. A portion
of the liquid is collected by suctioning through the bronchoscope, and the recovered material
can be analyzed for cells (cytology) or organisms (by standard stains and cultures). Brushing or
biopsy of the surface of the lesion, using a small brush or biopsy forceps at the end of a long
cable inserted through a channel of the bronchoscope, allows recovery of cellular material or
tissue for analysis by standard cytologic and histopathologic methods.
The bronchoscope can be used to sample material not only from the regions that can be directly
visualized (i.e., the airways) but also from the more distal pulmonary parenchyma. With the
bronchoscope wedged into a subsegmental airway, aliquots of sterile saline can be instilled
through the scope, allowing sampling of cells and organisms even from alveolar spaces. This
procedure is called bronchoalveolar lavage.

34. CYSTIC FIBROSIS

35. • Cystic fibrosis (CF) is a monogenic disorder that presents as a
multisystem disease.
• The first signs and symptoms typically occur in childhood, but about
5% of patients in the United States are diagnosed as adults.
• Due to improvements in therapy, >46% of patients are now adults
(≥18 years old) and 16.4% are past the age of 30.
• The median survival is >37.4 years for patients with CF; thus, CF is
no longer only a pediatric disease.
• CF is characterized by chronic bacterial infection of the airways that
leads to bronchiectasis and bronchiolectasis, exocrine pancreatic
insufficiency and intestinal dysfunction, abnormal sweat gland
function, and urogenital dysfunction.
CYSTIC FIBROSIS (CF)

36. The prevalence of CF varies with the ethnic origin of a population.
CF is detected in approximately:
• 1 in 3000 live births in the Caucasian population of North America
and northern Europe,
• 1 in 17,000 live births of African Americans
• 1 in 90,000 live births of the Asian population of Hawaii.
The most common mutation in the CFTR gene (~70% of CF
chromosomes) is a 3-bp deletion (a class II mutation) that results in an
absence of phenylalanine at amino acid position 508 (ΔF508) of the CF gene
protein product, known as CFTR.
The large number (>1500) of relatively uncommon (<2% each) mutations
identified in the CFTR gene makes genetic testing challenging.
EPIDEMIOLOGY

37. • Born/year in Italy: more than 200 people
• Affected 5000-6000 people (40% adults)
• Carriers: meore than 2.200.000 people
• Median survaival: more than 35 years
• CF is the most common autosomic recessive disease
in caucasian population.
ITALIAN EPIDEMIOLOGY

38. CF is an autosomal recessive disease resulting from mutations
in the cystic fibrosis transmembrane conductance regulator
(CFTR) gene located on chromosome 7.
The mutations in the CFTR gene fall into five major classes.
Classes I–III mutations are considered "severe," as indexed by
pancreatic insufficiency and high sweat NaCl values.
Class IV and V mutations can be "mild," i.e., associated with
pancreatic sufficiency and intermediate/normal sweat NaCl
values.
THE DISEASE

39. POSITIONAL CLONAGE
• The CFTR gene was cloned in 1989

42. World Italy

44. The CFTR protein is a single polypeptide chain, containing
1480 amino acids, that functions both as a cyclic AMP–
regulated Cl− channel and as regulator of other ion channels.
The fully processed form of CFTR localizes to the plasma
membrane in normal epithelia. Biochemical studies indicate
that the ΔF508 mutation leads to improper maturation and
intracellular degradation of the mutant CFTR protein. Thus,
absence of CFTR in the plasma membrane is central to the
molecular pathophysiology of the ΔF508 mutation and other
classes I–II mutations.
Classes III–IV mutations produce CFTR proteins that are fully
processed but are nonfunctional or only partially functional in
the plasma membrane.
Class V mutations include splicing mutations that produce
small amounts of functional CFTR.
CFTR PROTEIN

45. The protein has six transmembrane domains, two intracellular
“nucleotide binding folds” (NBFs), and a regulatory domain (R
domain) containing a number of phosphorilation sites.
CFTR STRUCTURE

48. Schema describing classes of genetic mutations in CFTR gene and effects on CFTR protein/function. Note the ΔF508 mutation is a
class II mutation and, like class I mutations, would be predicted to produce no mature CFTR protein in the apical membrane. CFTR,
cystic fibrosis transmembrane conductance regulator.
Legend:
From: Chapter 259. Cystic Fibrosis
Harrison's Principles of Internal Medicine, 18e, 2012

49. CLINICAL MANIFESTATIONS
Epithelial Dysfunction
The epithelia affected by CF exhibit different functions in their
native state, i.e., some are volume-absorbing (airways and distal
intestinal epithelia), and some are salt- but not volume-absorbing
(sweat duct), whereas others are volume-secretory (proximal
intestine and pancreas). Given this diversity of native activities, it
is not surprising that CF produces organ-specific effects on
electrolyte and water transport. However, the unifying concept is
that all affected tissues express abnormal ion transport function.

50. Comparison of ion transport properties of normal (LEFT) and CF (RIGHT) airway epithelia. The vectors describe routes
and magnitudes of Na+ and Cl− transport that is accompanied by osmotically driven water flow. The normal basal pattern
for ion transport is absorption of Na+ from the lumen via an amiloride-sensitive epithelial Na+ channel (ENaC) composed
of α, β, and γ ENaC subunits. This process is accelerated in CF. The capacity to initiate cyclic AMP–mediated Cl−
secretion is diminished in CF airway epithelia due to abnormal maturation/dysfunction of the CFTR Cl− channel. The
accelerated Na+ absorption in CF reflects the absence of CFTR inhibitory effects on Na+ channels. A Ca2+-activated Cl−
channel, likely a product of the TMEM16a gene, is expressed in normal and CF apical membranes and can be activated by
extracellular ATP. Horizontal arrows depict velocity of mucociliary clearance (μm/sec).

51. AIRWAYS

52. Recurrent infections of upper and lower airways
• chronic sinusitis
• nasal polyps
• rhinorrhea
• cough with mucopurulent very viscous sputum
• recurrent bronchitis
• gradual deterioration of respiratory function
Alternating periods of stability with exacerbations
The bacteria involved are:
•Staphylococcus aureus ed Hemophilus influentiae during
childhood
• Pseudomonas aeruginosa in adults
More than 95% of deaths in CF patients are related to respiratory
tract infections.
RESPIRATORY MANIFESTATIONS OF
CF

53. • Pancreas: at this level the Cl-/HCO3
- exchange is altered
resulting in reduced secretion of water and bicarbonate in
pancreatic secretions; this is reflected in a non-complete
excretion of pancreatic enzymes that determines the onset of
chronic pancreatitis with gradual destruction of the parenchyma
(cyst formation and fibrous tissue)
• Bowel: the absorption of water and Na+ increases with
meconium ileus in 10% of infants and frequent episodes of
bowel obstruction in children and young adults.
OTHER MANIFESTATIONS OF CF

54. • Reproductive: occlusion of the deferens ducts in 95%
of males with azoospermia. Female infertility due to
mucous plug at the uterine cervix;
• Sweat Gland: excess sweat chloride, used as
important diagnostic test.
OTHER MANIFESTATIONS OF CF

56. DIAGNOSIS
The large number of mutations described makes DNA analysis
challenging in the diagnostic setting.
Clinical criteria
Sweat test:
The sweat glands secrete in their lumen high quantities of Na+
and Cl- which osmotically draw water .
The sudorifics ducts are waterproof and have the task to absorb
most of the electrolytes in order to avoid salts depletion.
In the case of the CF the reabsorption of Cl- in the sudorific ducts
is compromised and the concentration of Cl- in the sweat is very
high compared to normal subjects (> 70 mEq /L)

57. GENE THERAPY
A possible application of gene therapy was hypotesized
since1989, when it was sequenced and cloned the CFTR gene
(Riordan et al., 1989);
Transferring the CFTR gene into deficient CFTR cells lead, in
vitro, to the production of Cl- channels;
Theoretically transferring and making express airway cells of
patients with CF the CFTR gene, should resolve the disease;
gene therapy, in fact, addresses the basic effect rather than the
downstream consequences of the disease.
This approach has the potential to impact significantly on the
natural history of the disease.

58. VECTORS
The transfection efficiency of naked DNA is so low that gene
transfer agents (GTAs) have been designed to enhance entry to
the cell/nucleus.
• viral (Adenovirus, Adeno-associated virus, Sendai virus,
Lentivirus).
• non-viral, usually lipid-based, but also including nanoparticles
(cationic liposomes, compacted DNA nanoparticles).
Limits: inflammatory response (mainly with pathogens viruses),
host immune responses (that lead to absent gene expression
after subsequent exposure)