A Study to Document the Effect of Petrolatum on Innate Immune Responses in the Skin
Condition: Skin Disease
MeSH terms: Skin Diseases
Study type: Interventional

Summary: 
      Petrolatum is a very well-known emollient that has been used since the 1800's. Not only has
      it been used to help with dry skin, but it is also marketed as a substance that protects
      minor cuts and burns. In the past it was thought to be inferior to topical antibiotics in
      infection prevention for cutaneous wounds. However, in 1996 a large, multicenter trial
      including over 900 patients showed that petrolatum is as safe and effective as the topical
      antibiotic, bacitracin in preventing infections for patients undergoing dermatological
      surgery. In this trial, not only did the petrolatum group have similarly low rates of
      infection, this group also reported no cases of contact dermatitis. Aside from being more
      expensive than petrolatum, bacitracin and other topical antimicrobials (i.e. neomycin) have
      been known as common culprits of contact dermatitis. In a study done by the North American
      Contact Dermatitis Group between 2005-2006, 9.2 and 10% of the over 4,000 patients who were
      patch tested had an allergic reaction to either bacitracin or neomycin, respectively. For the
      above reasons, it is clear that petrolatum is an appealing alternative to topical antibiotics
      for infection prevention in patients undergoing dermatological procedures. This study however
      lacked any mechanistic analyses to provide molecular insight as to how petrolatum was
      effective at infection prevention.

      The aim of this research is to study the effect of petrolatum on innate immune reactions in
      the skin. In particular, petrolatum's effect on various antimicrobial peptides after contact
      with the skin for 3 days will be examined. This will be done through immunohistochemistry for
      various cellular infiltrates as well as mRNA gene expression via RT-PCR analysis for
      inflammatory and AMP genes. Tissue samples of petrolatum occluded skin will be compared to
      both healthy skin and skin under occlusion alone as controls. These comparisons will isolate
      the effect of the petrolatum on the skin.
    

Detailed description: 
      Petrolatum (also commonly called Vaseline) is a very well known moisturizer that has been
      used since the 1800's. Not only has it been used to help with dry skin, but it is also
      marketed as a substance that protects minor cuts and burns. It is widely used by
      Dermatologists as a substance to apply to wounds from cutaneous surgical procedures. In a
      large study, petrolatum was shown to be as effective as one of the major topical antibiotics
      to help prevent infection in patients who underwent dermatologic procedures. Not only are the
      other topical antibiotics expensive, but also they are commonly the cause of an allergic
      reaction in up to 10% of the population. Until now, no reason has been found to explain why
      petrolatum is effective in infection prevention. In a recent study, skin biopsies of skin
      that had petrolatum applied to them were obtained. Upon analysis certain "antimicrobial
      peptides" (peptides that possess anti-bacterial properties that help fight infection) have
      been found to be elevated. This could provide an answer as to why petrolatum was as effective
      as the topical antibiotic in the study mentioned above.

      This study hopes to improve our understanding of how the immune system acts and how the skin
      responds to petrolatum. In order to reach this goal, normal volunteers, will be patch tested
      with petrolatum. Then, biopsies will be taken of the skin at the sites where petrolatum was.
      Also, small biopsies will be taken from an area that received a patch but no petrolatum and
      an area that did not receive a patch to serve as controls. The biopsied skin samples will
      then be studied in a laboratory by methods such as immunohistochemistry and RT-PCR analysis,
      which will help define the response of the immune system to petrolatum. The rationale for the
      study is to better define petrolatum's effects in skin and how it is effective at preventing
      infections.
    

Intervention name(s): Petrolatum application under occlusion
Intervention type(s): Drug
Intervention description(s): Day 0 study patients will have 1 patch applied to either back or thighs ( containing 2 wells)
1 well will be empty and the other well will contain petrolatum
Day 3 patches will be removed and 3 skin biopsies will be performed 1 biopsy from normal skin at a distance from the patch
1 biopsy each from under the 2 wells of the patch ( so 1 biopsy from skin that was occluded with petrolatum and 1 biopsy from skin that was occluded without petrolatum)
Other intervention name(s): vaseline under occlusion
Intervention MeSH terms: Petrolatum
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science