ICADA Skin Barrier Flashcards
Issues with TEWL, an INDIRECT measurement of skin barrier function (3)
*Room temperature
*Humidity
*Inter/intraobserver variability
3 indirect measurements of skin barrier function that may be more reliable than TEWL
1) Corneometer (skin hydration)
2) pH meter
3) Colorimeter (erythema)
**Ideally: use above 3 in conjunction with vapometer for TEWL
Which 2 skin barrier measurement modalities correlate with disease severity
*TEWL (more water loss = more severe dz)
*pH (more basic pH = more severe)
How are ceramide levels in cAD dogs compared to healthy dogs?
Lower ceramides in cAD
Which ceramides are decreased in cAD dogs?
1) Ceramide 1 (CER[EOS])
2) Ceramide 9 (CER[EOP])
3) Ceramide (CER[NP])
How is the stratum corneum organized in atopic dogs?
Hexagonal lipid packing
How is the stratum corneum organized in normal, healthy dogs
Orthorhombic packing
Which ratio of ceramides is decreased in cAD dogs?
CER[NS] C44/C34
Lower ratio = more severe cAD
Which dogs have a filaggrin SNP mutation associated with their cAD
Labrador retrievers in the UK
Do most dogs with cAD have mutations in filaggrin?
No
Why does Santoro think studies evaluating filaggrin in cAD dogs may be flawed?
Potentially were investigating Filaggrin 2, rather than filaggrin.
Filaggrin 2 is a component of cornified envelope, makes NMF
Which enzymes are changed in nonlesional cAD dogs, compared to healthy dogs?
*Decreased Caspase-14 in cAD in 1 study
*Increased Caspase-14, Matriptase, Calpain-1 in another study
Which proteins are decreased in cAD? (6)
*Claudin-1 (tight junction)
*Occludin (tight junction)
*Corneodesmosin
*E-cadherin (adherens junction)
*Desmocollin-1
*Desmoglein-1
What are the 2 major microorganisms that are increased in cAD microbiome dysbiosis?
*Staphylcococcus pseudintermedius
*Malassezia pachydermatis
Which bacterial phyla are present in both healthy and cAD dogs, but increased in cAD skin?
*Actinobacteria
*Proteobacteria
*Firmicutes
*Bacteroidetes
*Tenericutes
Which Malassezia sp is predominant in healthy skin?
Malassezia globosa
Which Malassezia sp is predominant in cAD skin?
Malassezia pachydermatis
How long after allergy challenge does increase in abundance of Corynebacteria and Staphylococcus persist for?
2 weeks after remission of skin lesions
Right after resolution of pyoderma treatment, how does the cAD skin microbiome compare to healthy skin?
Goes back to normal for 4 weeks!
However, decreased diversity recurs within 4-6 weeks
Which bacteria have increased abundance in the external ear canal of cAD dogs?
*Staphylcococcus (Firmicutes)
*Ralstonia (Proteobacteria)
Which bacteria have an increased abundance in HEALTHY external ear canals compared to cAD?
Escherichia sp
Most common microbial SPECIES on healthy skin?
(Tang et al 2020)
*Cutibacterium acnes
*S. pseudintermedius
*Porphyromonas cangingivalis
*Capnodiales (unclassified fungal species)
*Alternaria sp
Most common microbial SPECIES on cAD skin
(Tang et al 2020)
*S. pseudintermedius
*S. schleiferi
*Bacteriodes pyogenes
*Peptoniphilus grossensis
Most common microbes in healthy ears
(Tang et al 2020)
*Cutibacterium acnes
*S. pseudintermedius
*Streptococcus sp.
*M. pachydermatis
*Capnodiales (fungal)
*Pleosporales (fungal)
Most common microbes in cAD ears
(Tang et al 2020)
*Malassezia pachydermatis
*Staphylococcus pseudintermedius
*Staphylococcus scheliferi
+ Anaerobes
*Finegoldia magna
*Peptostreptococcus canis
*Porphymonas cangingivalis
How does phototherapy affect the microbiome on cAD skin?
*DECREASED S. pseudintermedius with UVB phototherapy
*INCREASED Actinobacteria & Cyanobacteria
How do Malaseb baths BIW affect the microbiome on cAD skin?
*No change in bacterial microbiome
*Decreased fungal diversity while using shampoo, but returned to normal after 4 weeks
What are the 2 main host defense peptides?
*Beta-defensins
*Cathelicidins
In dogs with cAD or infection, what happens to gene expression of host defense peptides?
Of protein expression?
INCREASED
BUT protein expression is NOT always decreased –>dysregulation of synthesis of host defense peptides
Where are host defense peptides in cAD skin?
(Within keratinocytes or secreted?)
Retained within keratinocytes
How is the action/function of host defense peptides in cAD skin compared to healthy skin?
Decreased functionality (lower antibacterial inhibitory effect)
How is the dispersion of host defense peptides in cAD skin compared to healthy skin?
HDP are usually attached to skin surface, rather than secreted effectively
What are the 3 major differences in host defense peptides in cAD vs healthy skin (and ears)
cAD has:
*Decreased secretion (retained in keratinocytes)
*Decreased dispersion (attached to skin surface)
*Decreased antibacterial efficacy
