Transcript I. BACTERIA Percent Shift from Gram Positive (facultative) to Gram

Inflammatory
Periodontal Disease
Dr. Robert J. Boackle
Select here for the Lecture Notes
I. BACTERIA
Percent Shift from Gram Positive
(facultative) to Gram Negative-Anaerobes in
Supragingival Plaque in Gingivitis.
In Periodontitis - “SUBGINGIVAL PLAQUE”
Two Very Important GRAM NEGATIVE Bacteria
Closely Associated with with Periodontal Disease:
• Porphyromonas gingivalis
• Actinobacillus actinomycetemcomitans
•Porphyromonas gingivalis
•http://biology.kenyon.edu/Microbial_Biorealm/bacteria/bacteroide
te_chlorob_group/Porphyromonas/porphyromonas.htm
May travel between cells (intercellular movement)
via bacterial protease action
and/or
Into cells (e.g., into and through epithelial
cells) termed intracellular movement and
multiply in those host cells
http://iai.asm.org/cgi/content/full/69/4/2700
causing release of pro-inflammatory cytokines
Other Implicated Periopathogens:
• Bacteroides forsythus
Fusobacterium nucleatum
Prevotella intermedia
Campylobacter rectus
Eikenella corrodens
But these Periopathogens may be
detected both in inflammatory and
in non-inflammatory sites of
periodontal patients, as well as in
the healthy subjects.
“Porphyromonas gingivalis, one of the major causative agents of
periodontal diseases, produces large amounts of arginine- and
lysine-specific cysteine proteinases in cell-associated and secretory
forms, which are now referred to as Arg-gingipain (abbreviated Rgp
or Arg-X) and Lys-gingipain (abbreviated Kgp or Lys-X), respectively.
…..With respect to the physiology of the bacterium, Rgp and Kgp are
indispensable for it to obtain nutrients from the environment, since
Porphyromonas gingivalis cannot utilize saccharides as
carbon/energy sources for growth and totally depends on peptides
and amino acids that are provided from environmental proteins by
Rgp and Kgp. Furthermore, proteolytic activities of Rgp and Kgp
contribute to processing/maturation of various cell-surface proteins
of P. gingivalis, such as fimA fimbrilin (a subunit of major fimbriae),
75-kDa protein (a subunit of minor fimbriae), hemagglutinins, and the
hemoglobin receptor protein, which are important for the bacterium
to colonize and proliferate in the gingival crevice and to invade the
periodontium. These findings strongly indicate critical roles of Rgp
and Kgp in the virulence of P. gingivalis.”
Taken from, Kadowaki et al., Journal of Biochemistry, Vol 128, 153159, 2000 http://jb.oupjournals.org/cgi/content/abstract/128/2/153
Porphyromonas gingivalis with chronic and severe
adult periodontitis
Actinobacillus actinomycetemcomitans with
Localized Aggressive Periodontitis (LAP)
(formally termed Advanced Onset Periodontitis
and localized juvenile periodontitis)
Treponema denticola and Prevotella intermedia
with acute necrotizing gingivitis
Coronary Heart Disease and Periodontal Disease
http://atvb.ahajournals.org/cgi/content/full/25/3/e17
High-serum antibody levels to major periodontal
pathogens are associated with subclinical,
prevalent, and future incidence of coronary
heart disease (CHD). Periodontal pathogens or
host response against them may contribute to
the pathogenesis of CHD.
Pussinen PJ, Nyyssonen K, Alfthan G, Salonen R, Laukkanen JA, Salonen JT. Serum antibody levels to
Actinobacillus actinomycetemcomitans predict the risk for coronary heart disease. Arterioscler Thromb Vasc
Biol. 2005, 25: 833-838.
Pro-atherogenic properties of lipopolysaccharide from the periodontal pathogen
Actinobacillus actinomycetemcomitans
http://www.musc.edu/~boacklrj/Aa.pdf
http://www.musc.edu/~boacklrj/Porph-Atherosclerosis.pdf
Periodontal disease and bacterial vaginosis
increase the risk for adverse pregnancy
outcome. Oittinen J, Kurki T, Kekki M,
Kuusisto M, Pussinen P, Vilkuna-Rautiainen
T, Nieminen A, Asikainen S, Paavonen J.
Infect Dis Obstet Gynecol. 2005 13:213-216.
Will future reports substantiate this paper
concerning women attempting to become pregnant?
Please keep up with the Literature!
Supragingival Plaque
Note: Supragingival plaque, even from dental hygienists,
is a natural habitat for periodontitis-associated bacteria
in healthy persons. Colonization with:
Actinobacillus actinomycetemcomitans
Bacteroides forsythus
Campylobacter rectus
And is mostly stable in spite of better than average
personal plaque control of dental hygienists.
Bacterial colonization by;
Actinobacillus actinomycetemcomitans (serotype b)
and/or Porphyromonas gingivalis
appear to be Associated With
Early Onset Periodontitis (Juvenile Periodontitis)
Now termed -
Localized Aggressive Periodontitis (LAP)
seen in young people, is a rare condition characterized by severe
periodontal destruction around first molars and incisorswith little or
no accumulation of visible plaque and/or calculus.
It was previously named Localized Juvenile Periodontitis (LJP)
and recently reclassified as Localized Aggressive Periodontitis
(LAP).
BACTERIAL PROTEASES
i.e., from Porphyromonas
gingivalis
A percentage of these proteases remains associated with the
surface of the organism while the rest is liberated into the
surroundings
• Collagenases---------Directly damage the Periodontal Ligament which
is made of Collagen
• Gingipain proteases----The Lys-X (Lys-gingipain) and Arg-X (Arggingipain..RGP) cysteine proteases of PORPHYROMONAS
GINGIVALIS -Destroy intercellular “glue-like proteins”
• Antibodies directed to the amino-terminal region of the
catalytic domain of gingipains R are capable of inducing a
protective immune response against P. gingivalis infection
in the mouse chamber model.
The Bacterial Gingipain proteases-cysteine proteases
The Arg-X (Arg-gingipain..RGP) cysteine proteases &
The Lys-X (Lys-gingipain) cysteine proteases of
PORPHYROMONAS GINGIVALIS
a) Destruction of host intercellular
glue-like proteins:
E-cadherin
Beta1-Integrin and
Occludin
Other Actions of Bacterial Gingipain
proteases---The Arg-X (Arg-gingipain..RGP)
and Lys-X (Lys-gingipain)
cysteine proteases of
PORPHYROMONAS GINGIVALIS
b) Non-productive complement consumption and
removal of deposited complement components
(C3b) from the bacterial surface
c) Bradykinin release from kininogens• Crevicular Fluid (Exudate) Flow Increases
(Bradykinin is normally excised from kininogens by the enzyme
kallikrein)
Porphyromonas gingivalis
"Black pigmenting anaerobic bacilli”
Bind many cells (via its Hemagglutinin B) including epithelial
cells, and degrade erythrocytes (one reason for being “Black
Pigmented”)
Human Beta-Defensin 1 Interacts with Hemagglutinin B from
Porphyromonas gingivalis
Purified recombinant Hemagglutinin B (rHag B) is being used
in animal models to induce a protective immune response and
information may support the potential usefulness of this
component of P. gingivalis in the development of a vaccine
against adult periodontitis.
Serum IgA1
IgA antibodies codeposited with IgG
antibodies that are on
antigens or in the blood
will pick-up “accept”
complement fragments
in areas of
periodontal inflammation
– where complement
activation is occurring
C3b
iC3b
IgA1
And will “arm”
PMN
PMNs
Macrophages and
Immature Dendritic
Cells
These cells have
complement
receptors for C3b
iC3b and or C3d
fragments
C3b
iC3b
IgA1
PMN
And will “arm”
PMN
Macrophages and
Immature Dendritic
Cells
These cells have
complement
receptors for C3b
iC3b and / or C3d
fragments
CR1
C3b
CR3
iC3b
IgA1
BUT:
What if IgA1
proteases
released from
Periopathogens
e.g., P. gingivalis
Cleave IgA1
before the
complement is
deposited
PMN
CR1
C3b
CR3
iC3b
IgA1
Fc fragments
have
No ability to
bind antigen
IgA1
Thus this entire process is
not allowed to happen.
Nor will the properly
directed stimulation of
antibody responses occur.
Also in the absence o the
intact intercepting IgA1,
inadvertent deposition of
complement directly on
dendritic cells could nonspecifically stimulate the
immune system and lead to
IgG2 production.
Antigen Presenting Cells
(B cell or Immature
Dendritic Cell or
Macrophage
CR2
C3d
CR2
C3d
IgA1
P. Gingivalis Antigens
Effects of the IgA1 Proteases released
from periodontal pathogens and the
released of free Fcalpha1 and of free Fab
fragments to compete with intact
antibodies:
A lower degree of Specific B (and T) cell
responses, leading to a continued
infection and more non-specific
polyclonal antibody responses due to the
release of polyclonal activators (i.e., LPS)
and Superantigens.
Please read the references below regarding
proteases and periodontal disease
http://www.musc.edu/~boacklrj/BacterialProteases.pdf
http://www.musc.edu/~boacklrj/regulationGingipains.pdf
Please Use this site to
search for these
papers
http://www.scirus.com
BACTERIAL ANTIGENS
and
BACTERIAL MITOGENS
• Induce Mitosis of host lymphocytes
• B cell activation (Specific and/or Polyclonal)
• Differentiation into PLASMA CELLS
• [Note: a relatively large number of
plasma cells is present in inflamed
periodontal tissues]
Contact with BACTERIAL ENDOTOXINS
(Lipopolysaccharides--LPS)
Several different Toll-Like Receptors (TLR) for LPS
are on host cells—
activation of nuclear factor-kB (NF-kB) indicates the production of
Proinflammatory Cytokines from those host cells.
http://www.musc.edu/~boacklrj/Cytokines-TLR-Periodontal.pdf
http://www.musc.edu/~boacklrj/osteoclast-Bcell.pdf
http://www.musc.edu/~boacklrj/Cytokines-Periodontal-PArt2.pdf
http://www.musc.edu/~boacklrj/hyporesponsiveness.pdf
• INDIRECTLY Activate OSTEOCLASTS-mediated Bone resorption via the
stimulation of the production of the above mentioned pro-inflammatory cytokines
e.g., Interleukin 1 (IL-1) and IL-6http://www.musc.edu/~boacklrj/Cytokines-Bone-Loss.pdf
• Or via direct interactions of antigen stimulated B Cells with Osteoclasts
http://www.musc.edu/~boacklrj/osteoclast-Bcell.pdf
• Also the Coating of periodontal tissues with Bacterial Products like endotoxin may
disrupt a timely healing.
• Endotoxins are neutralized by Complement, if sufficient amounts of complement
are present
Direct BACTERIAL
CHEMOTACTIC FACTORS
---from living bacteria
n-formyl-methionine residue
Attract PMN (if PMNs are
normal)
II. HOST RESPONSE
Inflamed Gingival Tissues:
Crevicular Fluid Flow Rate Increases
HOST RESPONSE
Crevicular Fluid Flow Rate Increases
Crevicular Fluid is a serum exudate
HOST RESPONSE
In the Inflamed Gingival Tissues:
Important digestive enzymes released from Our (HOST)
PMNs, macrophages and Fibroblasts
1)
Human Leukocyte Elastase
from PMN and Macrophages
2)
Human Matrix Metalloproteinases (MMP)
(IL1- induced) from PMN, macrophages and fibroblasts
3)
Lysozyme digests peptidoglycan, a part of the
backbone of gram positive Bacterial cell walls
Human Leukocyte Elastase
A powerful host protease released from PMNs (termed HLE)
and Macrophages (also termed MMP-12)
Important Substrates of Elastase in inflammatory situations
like periodontal disease:
•
Elastin (matrix destruction)
• C1 Inhibitor (deregulates Classical and Lectin
complement pathways)
• Alpha-1-proteinase inhibitor (alpha1-PI)
Human Matrix Metalloproteinases
IL1- induced MMPs released from PMN,
macrophages and fibroblasts (Certain
Tetracyclines may inhibit MMP activity).
some MMPs are Zn++ dependent
These are Host Collagenases
We Destroy our own
Collagen (e.g., periodontal ligament)
C1 (collagen part)
Mannan Binding Lectin (collagen part)
SPECIFIC ANTIBODY
Neutralizes BACTERIAL SUBSTANCES e.g., bacterial proteases
“Antibodies to gingipain promote uptake of P. gingivalis by PMNs”
Gibson et al. Gingipain-specific IgG in the sera of patients with periodontal disease is necessary for
opsonophagocytosis of Porphyromonas gingivalis. J Periodontol. 2005 Oct;76(10):1629-36.
In the inflamed periodontal tissues, both IgG and IgA are produced in
situ. This means that plasma cells in the periodontal tissues are
liberating IgG or IgA1, then later IgA2 antibody producing plasma cells
appear. While the IgG (especially IgG3 and IgG1) activates the classical
pathway of complement, serum IgA1 and perhaps IgA2 antibody appear
to have a regulatory and transport mechanism in complement activation
and preserve IgG1 binding.
IgG2 is a weaker complement activator that is produced “out of
proportion” in response to Actinobacillus actinomycetemcomitans.
http://www.musc.edu/~boacklrj/Actinobacillus-specific-IgG.pdf
Complement
• Neutralizes BACTERIAL SUBSTANCES via the classical complement
pathway (immune complexes) and via the alternative pathway. Covalent
C3b binding changes the nature of the bacterial LPS-endotoxin and
detoxifies it.
• C5a --Chemotactic factor (high level of PMN in diseased periodontal
tissues). PMNs release oxygen radicals to kill microbes in the
phagolysozome) but these radicals when released (leaked) outside the
PMNs can cause damage to surrounding host tissues.
• Complement can damage host tissue (bystander membrane attack
complex).
• Our periodontal host cells (fibroblasts, epithelial cells etc.) up-regulate their
expression of membrane complement inhibitors (DAF and Protectin) to
protect themselves against inadvertently deposited C3b and MAC and resist
bystander damage by the membrane attack complex of complement.
Lymphocytes
• The adaptive immune response, and in particular stimulated CD4 positive T
cells and the pro-inflammatory cytokines that they secrete (IL1 and IL6), are
important effectors of bone loss consequent to Porphyromonas gingivalis
oral infection. In animal studies, mice genetically lacking the cytokine
"gamma interferon" or "interleukin-6" demonstrated decreased bone loss
during the infection.
• Cytotoxic T Lymphocytes may also release lymphotoxins, which kill host
cells, perforins, which can damage host cell membranes and release
chemotactic factors (interleukins) attracting PMNs.
• Endotoxin induced Tolerance to suppress the specific immune response?
http://www.musc.edu/~boacklrj/hyporesponsiveness.pdf
Lower number of Toll-Like Receptors?
Involvement of HUMAN GINGIVAL FIBROBLASTS
Human Matrix Metalloproteinases (IL1- induced) liberated
from fibroblasts (and PMN) in the inflamed tissue
When contacting Human gingival fibroblasts
There is an "additive" effect of both
IL-1 along with P. gingivalis - LPS on IL-6 production by Osteoblasts
Result
Bone Resorption
HUMAN EPITHELIAL CELLS--Eikenella corrodens and “intracellular” habitation by P. gingivalis
induces the human epithelial cells to secrete pro-inflammatory
cytokines (IL-6 and IL-8) which serve as an early signaling system to
host immune and inflammatory cells in underlying connective tissues.
"DEFECTS" in PMN / lymphocyte function
Advanced Onset Periodontitis (Localized Juvenile
Periodontitis)
Diabetes------Prolonged high glucose levels lead to altered
energy metabolism (PMN dysfunction),
and to abnormal glycosylation of serum proteins and “many cellsurface receptors” leading to cell malfunction and a weaker
immune response.
Secondary PMN and lymphocyte dysfunction may occur in
uncontrolled diabetes.
AIDS Patients ---Develop Periodontal Disease
PLASMA CELLS
High levels of plasma cells in
gingival tissue with production of
A) Specific Ab and
B) Non-specific Ab
SPECIFIC ANTIBODY PRODUCED in
situ
Important points concerning Specific IgG, IgA, complement
and periodontal disease:
Specific IgG, IgA1 and IgA2 antibody to subgingival
Periodontal Pathogens are produced in situ by local plasma
cells in the inflamed periodontal tissues.
“Antibodies to gingipain promote uptake of P. gingivalis by PMNs”
Gibson et al. Gingipain-specific IgG in the sera of patients with periodontal disease is necessary
for opsonophagocytosis of Porphyromonas gingivalis. J Periodontol. 2005 Oct;76(10):1629-36.
Some Periodontopathic Bacteria (P. gingivalis)
produce IgA1 proteases specific only for IgA1
Why does this protease help the periodontopathic
bacteria to survive in the subgingival tissues?
Potential Exam question?
Non-specific salivary Ab
Salivary IgA Antibody to Sheep
erythrocytes is present in 1/2 of the
severe periodontal disease cases
that diminishes after successful
periodontal surgery
Why?
Please read the ABSTRACTS in the back of your
Handout.
These abstracts will help with your National Boards
(Part 1 and especially Part 2).