Hydration Hypothesis

A False theory about Silicone and Scars disproved by its own Author, but still being followed by most Scar Companies

Scar Occlusion-Hydration hypothesis:
  • the positive mechanism of action of silicone on scars is Hydration (2009)  
  • Silicone occlusive properties cause hydration and scar reduction
  • hydration is caused by silicone trapping TEWL (Trans Epidermal Water Loss) 
  • The Plastic Surgical community endorses the hydration hypothesis 
  • Plastic surgeon and researcher Professor Dr. Thomas Mustoe is proponent
  • In a latter paper (2017) Mustoe refutes the hydration hypothesis 

1.Role of Epidermis and Mechanism of Action of Occlussive Dressing in Scarring 2009 Mustoe https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3725331/?log$=activity

2.Occlusion regulates Epidermal CytokinProductionand Inhibits Scar Formation 2010 Mustoe et al https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2860621/

3. S100 A12 Induced in the Epidermis by reduced Hydration Activates Dermal Fibroblast and Causes Dermal Fibrosis Mustoe 2017 https://www.jidonline.org/article/S0022-202X(16)32638-0/fulltext 

Comment & Opinion - A completely failed Hypotheis

In a 2009 paper "The Role of the Epidermis and Mechanism of Action of Occlusive Dressings in Scarring" (Mustoe , Gurjala) pressent  the Occlusion Hypothesis - Hydration hypothesis is deficient in all manners, from assertions proposed, lack of logical consistency between them, as well as a lack of consistency with other research, studies and experimental results in the field.  It is hard to understand why Dr. Mustoe a preeminent scar and siliocne researcher from the Plastic surgery community would produce such a Hypothesis and paper with so many shortcomings.  Recenty in 2017 " S100 A12 Induced in the Epidermis by reduced Hydration Activates dermal Fibroblast and Causes Derma  Fibrosis" (Mustoe et al) 

Dr. Mustoe has conflicts of interest 
    Plastic Surgeons are advocates downplaying the biological effects of Silicone. That is because they are more interested in maintaining their Silicone breast implants business ( $1 billion in 2016  $2 billion projected for 2025).  Dr. Mustoe a practising plastic surgeon and professor of plastic surgery, and a high ranking member in Plastic Surgery community. It is best for Plastic surgery and Dr. Mustoe interest that it is accepted that silicone is biologically inert. This is why Dr. Mustoe is peddling this false Hypothisis which amounts to Scientific misconduct     

Critique of claims in Dr. Mustoe's : "The Role of the Epidermis and the Mechanism of Action of Occlusive Dressing in Scarring" 2009 

Claim 1: "Dermal fibrosis is exquiisitively linked to the inflamatory state of the epidermis, which is linked to the hydration state as a function of epidermal barrier function."

Comment: Here Mustoe is confounding two  inflamatory states of the epidermis . One is a non-biological   swelling  of the epidermis due to hydration.(1) The other is inflamation due to keratinocyte differentation, proliferation and lack of adhesion between keratinocytes causing group rounding instead of the normal flattening as they migrate to skin surface. (2)

Claim 2 : 'Previously , the epidermis has largerly been ignored as playing a role in scarring , because it is not a site for collagen synthesis... " 

Comment : The role of the epidermis in scarring had been presented July ,2002 by Tom Fallon to the FDA scientific committee for the classification of silicone sheeting on problem scarring. This FDA presentation was approved by the FDA Scientific committee, but in a unpresedented move opposed by the FDA . Much of the ideas claimed as "unique" in this Mustoe paper were originally  given in the FDA presentation seven years earlier.

claim 3:The maturity or functionality of the stratum corneum as a water barrier can be quantified by measuring water loss from the skin or indirectly by the hydration of the epidermis.

comment : Needed is  a paper citation to which shows that impedding TEWL by occlusion hydrates the epidermis.

claim 4 the stratum corneum functions  as a water barrier and until barrier becomes fully competent, there is a proliferation signal to restore homeostasis which have secondary effects on the dermis with a net increase in scar.

comment: barrier of water coming in or out? startum corneum are dead flat cells empty of a nucleus . No form of signal transduction can emenate from them. Compentence is measured by the strength of the adhesions between corneocytes. 

Conclusion: Occlusive dressings such as siliocne gel in its various forms or other alternatives reduce reactive epidermal hyperplasia and IL-1 signaling presumably due to their ability to restore barrier function reducing TEWL and therefore increasing skin hydration. 

comment: Mustoe completely contradicts this conclusion in a latter paper  (3) were reduced Hydration in the Epidermis activates Fibroblast and causes Dermal Fibroblast thus refuting his own theory of Ocllusion and Hydration.