2. CONTENT
-Introduction
-Host Modulation
-Host Modulating Agents
-History Of Tetracycline
-Mechanism of action of tetracycline
-Structures of Chemically modified tetracycline
-Properties And Advantages Of CMTs Over Tetracylines
-Mechanism Of Action Of CMT
-Pleotrophic action of CMT
-Other uses of CMT
3. Introduction
• Periodontal disease is a complex inflammatory
disease characterised by destruction of tooth
supporting soft and hard tissue of periodontium
including PDL and alveolar bone .
4. • Although it is initiated by bacteria, tissue break
down events that leads to clinical signs results from
host inflammatory response that develops to combat
challenge presented by subgingival biofilm.
6. According to this model
• Pathogenesis of periodontitis: new findings and new
perspectives
- limited number of specific bacteria are essential to initiate
disease and fuel progression but insufficient to explain the
prevalence and severity of periodontitis
- Host factors are major determinants of disease occurrence
and severity
- Subgingival microbial plaque behaves as a biofilm (difficult to
eradicate by antimicrobial means and are protected from host
defense mechanisms).
7. Host modulation therapy (HMT) –
• It is a treatment concept that aims to reduce the tissue
destruction and stabilize or even regenerate the
periodontium by modifying or down regulating
destructive aspects of the host response and up
regulating protective or regenerative response
9. Figure 6 : Schematic illustration of the pathogenesis of periodontitis, including
targets for host modulation, depicting the action of CMTs on MMPs
10. Tetracycline
• Tetracyclines were first discovered by Dr. Benjamin Dugger
of Lederle Laboratories in the mid 1940s as the fermentation
product of an unusual golden-colored soil bacterium aptly
named Streptomyces aureofacians.
• The nomenclature is according to chemical nature i.e 4 ring
structure
• It is broad spectrum antibiotics acts by inhibiting protien
synthesis.
• Peak concentrations of 5-12 μg/ml reaches in the gingival
crevicular fluid (GCF) at 3.5-7 hours.
12. Mechanism of action of Tetracycline
• Tetracycline is bacteriostatic in action.
• It binds to 30s ribosome in susceptible organism due
to that attachment of aminoacyl t-RNA to m-RNA
ribosome complex is interferred, as result peptide
chain fails to grow.
13. • Advantages of this group of antibiotics were their
effectiveness against anaerobic gram-negative
periodontopathogens in the subgingival plaque,
increased concentration in gingival crevicular fluid at
levels 2-10 times greater than that of serum after a
single 250 mg dose.
14. • The substantivity property which enabled them to
bind to the biological tissues and get released over a
period of time, resulting in prolonged efficacy and
anti-collagenase property.
15. • Used frequently in treatment of refractory
periodontitis and LAP.
• It has the ability to concentrate in the periodontal
tissue and inhibit the growth of Aggregatibacter
actinomycetemcomitans.
• Exert an anticollagenase effect that can inhibit bone
destruction and may aid bone regeneration.
16. Dose Systemically: (In Chronic periodontitis, localized aggressive
periodontitis; generalized aggressive periodontitis; medically related periodontitis; necrotizing
ulcerative periodontitis; refractory periodontitis.)
(Given before periodontal surgery and continued for 4 to 7 days after surgery)
• Tetracycline 250mg 4 times daily (qid) for 2
weeks
• Doxycycline 100mg once in a day on first day
(qd) 100 mg bid from next day.
17. Side effects
- GI disturbances,
- photosensitivity,
- increased blood urea nitrogen,
- tooth discoloration when administered to
children up to 12 years.
18. In LDD: (as an adjunct to nonsurgical
treatment of periodontal disease)
• Tetracycline containing Fiber
(12.7mg per 9 inches, concentrations reach 1300µg/ml)
• Subgingival Doxycycline
(A gel system using a syringe with 10% doxycycline
(Atridox).
• Subgingival Minocycline
(locally delivered sustained release form of minocycline
microspheres (arestin)
19. Chemically Modified Tetracycline
(CMT)
• Golub et al., in 1987 recognized that the
antimicrobial and anti collagenase properties of
tetracyclines resided in different parts of the four
ringed structure.
• They altered the structure of tetracyclines which
led to the development of the CMTs.
20. • Antibacterial activity of tetracycline must possess a
linearly arranged DCBA naphthacene ring system
with an A-ring C1-C3 diketo substructure and an
exocyclic C2 carbonyl or amide group.
• All TCs that act as inhibitor of protein synthesis in
bacteria need the amino group in position C4 and
keto-enolic tautomers in position C1 and C3 of the
A ring.
21. • The amino group in the C4 position is pivotal for the
antibacterial activities
• Ca+ and Zn+ binding sites at the carbonyl oxygen and
the hydroxyl groups of carbon-11 and carbon-12
positions are responsible for the anti-collagenase action
of the CMTs.
22. • CMT-5 is a pyrazole analog of tetracycline, formed
by replacement of carbonyl oxygen at c-11 and
hydroxyl group at C-12 by nitrogen atoms.
• It does not have metal-binding site and therefore it
is inactive against MMPs. So, the only CMT found
to have lost its anti-collagenase property was
CMT-5.
23.
24. • The first non-antibiotic property discovered has
been the ability of tetracyclines to inhibit various
zinc-dependent enzymes of the matrix
metalloproteinase (MMP) family (Hanemaaijer et al.,
1998; Ramamurthy et al., 1999; Maisi et al., 1999;
Brown, 1995)
• Chang et al (1994) studied that tetracycline inhibits
porphyromonas gingivalis induced alveolar bone loss
in rats by non antimicrobial mechganism.
25. • Liavaneras et al(2001) studied that CMT and
Bisphosphonates synergistically inhibits endotoxin-
induced periodontal breakdown in rats.
• According to Holmeset al (2004) CMT acts through
multiple mechanism directly on osteoclast precursors.
• Cazalis et al ( 2009) stated that CMT modulates the
cytokine secretion by LPS- stimulated whole blood.
31. • CMTs have shown to be potent inhibitors of tissue
and matrix breakdown and attend longer half life in
serum than in tetracyclines.
• CMTs are potent inhibitors of
matrixmetalloproteinases (MMPs) and iNOS
(inducer nitric oxide synthase).
32. • A major advantage of CMTs (unlike tetracyclines) is
the lack of antimicrobial activity and lack of
development of antibiotic resistant microbial flora in
vivo in long term therapy.
33. Properties and advantages of CMTs over
tetracylines:
• Advantages of CMT over conventional tetracyclines are
that chronic use does not result
in gastrointestinal toxicity and higher plasma levels can
be achieved for extended time span reducing
administration frequency.
• The inhibition of mammalian collagenase.
34. • The CMTs have been shown to modulate integrin
expression on endothelial cells in early stages of
inflammation.
• They counteract the effects of Transforming
growth factor β-1induced expression of MMPs,
secretion of proinflammatory cytokines and
expression of FcϒRIII which enhances
phagocytosis.
35. • Mechanism of action
CMTs are used as HMT agents in the management of
periodontitis by
1) Inhibition of MMPs,
2) Inhibition of inducible nitric oxide synthase (iNOS)
3) Inhibition of bone resorption
4) Biologic role in inflammation and wound healing
36. 1)Inhibition of MMP :
The anti-MMP actions of CMTs include
- Direct inhibition of the active MMPs by the virtue of
Ca2+ and Zn2+ binding sites,
- Inhibits reactive oxygen species-mediated activation of
pro-MMPs.
- Proteolysis of pro-MMPs into enzymatically inactive
fragments.
- Protection of α-1 proteinase inhibitor from MMPs,
reduction in the activity of serine proteinases.
37. • Polymorphonuclear leucocytes (PMNs) provide the
major source of collagenases that mediate the
connective tissue breakdown during inflammatory
periodontal disease, while the fibroblasts contribute
the collagenase required for connective tissue
remodeling in normal gingiva.
• The anti-collagenase activity of CMTs is specific
against the collagenase produced from neutrophils
but not the fibroblasts.
38.
39. • The CMT-3 is specifically active against MMP-2,
MMP-9 and MMP-14 isozymes due to its
pleiotropic action toward MMPs. (2,9,14)
• It exerts an inhibitory effect on MMPs in
micromolar concentrations by decreasing
trypsinogen-2 and inducible nitric oxide (iNOS)
production.
40. • A comparative evaluation of six different CMTs in
inhibition of MMPs showed that the CMT-8 most
effective inhibitor of periodontal breakdown.
• CMT-8,-1, -3, -4, -7 and doxycycline inhibit tumor
necrosis factor-α (TNF-α), interleukin-1 (IL-1),
interleukin-6 (IL-6) and MMPs in descending order.
41. 2) Inhibition of inducible nitric oxide synthase
• The peroxynitrite radical formed by the reaction of NO is
highly cytotoxic, inhibits collagen and proteoglycan
synthesis and upregulates the MMP expression.
• CMT-3 inhibits the inducible nitric oxide synthase
activity, thereby reducing nitric oxide which is one of the
activators of MMPs.
42. • Inhibition of iNOS (inducible nitric oxide synthase)
production causes reduction in the peroxynitrite levels,
thus preventing denatuartion of proteins.
• CMT-3 and CMT-8 have maximum inhibitory effect
on the iNOS and CMT-1 and-2 have an intermediary
effect .
43. 3) Inhibition of bone resorption
• CMTs such as CMT-3 and CMT-8
- inhibits osteoclastic bone resorption and promote bone
formation,
- enhance wound healing and inhibit proteinases produced
by periodontal pathogens.
• CMT-1, CMT-3, CMT-6, -7 and -8 were effective
inhibitors of osteoblastic collagenase in culture.
• CMT-8 is the most potent among these.
44. • CMTs inhibit bone resorption by various mechanisms which
include
- reduction in number of osteoclasts by inhibiting their
development and inducing apoptosis,
- by altering the ruffled border and increasing the size of clear
zone,
45. -by decreasing the production of osteoclastic enzymes
like TRAP and Cathepsin-L which degrade organic
components of bone, inhibits osteoclastogenesis,
46. - elevates intracellular calcium levels which makes the
osteoclasts to detach from bone resorbing site,
- inhibits osteoclasts collagenase production and also
decreases acid production, thereby inhibiting bone
resorption, thus preventing the progression of
periodontal disease.
47. 4) Biologic role of CMT in inflammation and
wound healing
CMTs inhibit release of IL-1β, IL-6, IL-8, TNF-α and
prostaglandin-E2 (PGE2) from LPS-stimulated host
immune cells by suppressing phosphorylation of the nuclear
factor κ-B cell signaling pathway .
48. • CMTs increase integrin expression on endothelial cells in
inflammation,
• counteract the effects of (TGF-β) - induced expression
of transforming growth factor-β (expression of
MMPs), enhance phagocytosis by increased expression
of FcγRIII.
• Stimulate fibroblasts to produce protease inhibitors like
tissue inhibitors of matrix metalloproteases (TIMPs).
49. • The CMT-3 inhibits cyclooxygenase-2
(COX-2)-mediated PGE-2 production.
• CMTs are designed to be more potent inhibitors of
proinflammatory mediators and can increase levels of
anti-inflammatory mediators such as IL-10.
50. • CMTs promote matrix and collagen deposition and inhibit
bone resorption through anti-MMP and pro-TIMP actions
and reduced activity of inflammatory cytokines (e.g.
IL-1, IL-6, TNF-α) and PGE2.
• These pleiotropic mechanisms of CMT provide significant
therapeutic potential for treating periodontitis and various
other chronic inflammatory conditions.
53. • Mediated by extracellular mechanism
-Direct inhibition of active MMPs by cation chelation
(dependent on Ca2+ and Zn2+binding properties)
-Inhibits oxidative activation of latent MMPs
(independent of cation-binding properties
54. • Mediated by cellular regulation
-Scavenges and inhibits production of reactive oxygen
species produced by neutrophils.
-Inhibits MMPs and reactive oxygen species thereby
protecting alpha 1-proteinase inhibitor, and thus
indirectly reducing tissue proteinase activity.
-Inhibit the expression of nitric oxide synthatase thus
overproduction of nitric oxide is reduced.
-Down regulates expression of key inflammatory
cytokines (IL-1, IL-6, TNF – alpha and PGE2 ).
55. • Mediated by pro – anabolic effect
- Stimulates fibroblast collagen production
- Reduces osteoclast activity and bone resorption
- Blocks osteoclast MMPs
- Stimulate osteoblastic activity and bone formation
56. • CMTs also stimulate the production of matrix
molecules and protease inhibitors like tissue
inhibitors of matrixmetalloproteinase-1 (TIMP-1)
from fibroblasts
57. • The CMT-3 is specifically active against MMP-
2,9,14 isozymes due to its pleiotropic actions
toward MMPs.
• It exerts an inhibitory effect on MMPs in
micromolar concentrations by decreasing
trypsinogen-2 and inducible nitric oxide production.
58. Commercially Available CMT
• Incyclinide CMT-3 Metastat .(COL-3)
• COL-3 is absorbed slowly from the gastrointestinal
tract. 3% are excreted through the urinary
tract while 55–66% is excreted in feces.
• Most COL-3 binds to serum albumin.
59. • Other medical uses:
1. As antifungal agents
2. Inhibition of intimal thickening after arterial injury
3. Inhibition of orthodontic tooth displacement
4. Against advanced cancers
5. In diabetes mellitus
6. For rheumatoid arthritis
7. For acne and acute respiratory distress syndrome
8. Tumor metastasis.
60. Refrences
. Fuoco D. Classification Framework and Chemical Biology of Tetracycline structure based drugs. Cornell
University Library. Arxiv. org/ quantitativebiology/ biomolecules/arXiv:1111.2769v2.
2. Agnihotri R, Gaur S. Chemically modified tetracyclines:Novel Therapeutic agents in the management of
Chronic Periodontitis. Indial J Pharmacol 2012;44:161.
3. Sapadin AN, Fleischmajer R. Tetracyclines: Non Antibiotic Properties and their clinical implications. J
Am Acad Dermatol 2006;54:258-65.
4. Patel RN, Attur MG, Dave MN, Patel IV, Stuchin SA, Abramson SB,Amin AR. A Novel Mechanism of
Action of Chemically Modified Tetracyclines: Inhibition of Cox-2- Mediated Prostaglandin E2 production.
J Immunol 1999;163:3459.
5. Weinberg MA, Bral M. Tetracycline and Its Analogues: a Therapeutic Paradigm in Periodontal Diseases.
Crit Rev Oral Bio Med 1998;9(3):322.
6. Golub LM, Lee HM, Ryan ME, Giannobile WV, Payne J, Sorsa T. Tetracylines inhibit connective tissue
breakdown by multiple non-antibacterial mechanisms. Adv Dent Res 1998;12:12.
