Wound Healing in Healthy Volunteers
Condition: Wound Healing
MeSH terms: Wounds and Injuries
Study type: Interventional

Summary: 
      The skin plays a critical role in protection where it acts as a barrier from damage and
      pathogens between the external and internal environments. Wounds compromise its protective
      role by disrupting the function and the normal structure of the skin and the underlying soft
      tissue. As a response to injury wound healing occurs in order to rapidly restore the defect.
      This process involves activation of keratinocytes, fibroblasts, endothelial cells,
      macrophages, and platelets and consists of multiple phases including hemostasis,
      inflammation, migration and cellular proliferation, and maturation and remodeling. A
      simplified schematic of the course of wound healing is depicted in Figure 2. Hemostasis
      occurs immediately after dermal injury. The inflammation phase is characterized by cellular
      recruitment and increased vascular permeability. The epithelization phase is achieved by
      proliferation of basal cells and migration of epithelial cells. The last phase is known as
      the maturation and remodeling phase where collagen cross-linking and remodeling, wound
      contraction, and repigmentation takes place. Due to the broad involvement of various cell
      types, extracellular matrix and many reactive molecules each phase in wound healing produces
      characteristic changes within the tissue. A deficiency in any part of the process can lead to
      delayed wound healing, abnormal scar formation or chronic wounds.

      To study wound healing in healthy volunteers a challenge model with skin punch biopsies has
      been described in literature previously. However, the characterization of this model was not
      performed comprehensively since advanced analysis of biopsies were omitted. Furthermore,
      analyses performed in previous studies only partially described wound healing processes
      either by insufficient time points for characterization or scarce simultaneous evaluations of
      multiple wound healing modalities.

      The overall aim of this study is to develop a standardized model to temporarily and locally
      induce a skin trauma to investigate wound healing and monitor wound closure. This clinical
      model will enable future application as proof-of-pharmacology and proof-of concept studies as
      well as drug profiling in early drug development programs. More specifically, the objective
      of the trial is to explore and characterize the induction of well-defined skin trauma and
      natural wound healing process over the course of the different phases using a battery of
      dermatological assessments after skin punch biopsies in healthy volunteers. Furthermore,
      safety and tolerability will be assessed.

      Characterization and monitoring of wound healing effects following skin punch biopsies will
      be performed by means of biophysical, biochemical, imaging, clinical parameters and subject
      reported outcomes.
    

Detailed description: 
      Background & Rationale The skin plays a critical role in protection where it acts as a
      barrier from damage and pathogens between the external and internal environments. Wounds
      compromise its protective role by disrupting the function and the normal structure of the
      skin and the underlying soft tissue. As a response to injury wound healing occurs in order to
      rapidly restore the defect. This process involves activation of, among others, keratinocytes,
      fibroblasts, endothelial cells, macrophages, and platelets and consists of multiple phases
      including hemostasis, inflammation, migration and cellular proliferation, and maturation and
      remodeling. A simplified schematic of the course of wound healing is depicted in Figure 2.
      Due to the broad involvement of various cell types, extracellular matrix and many reactive
      molecules each phase in wound healing produces characteristic changes within the tissue. A
      deficiency in any part of the process can lead to delayed wound healing, abnormal scar
      formation or chronic wounds.

      To study wound healing in healthy volunteers a challenge model with skin punch biopsies has
      been described in literature previously. However, the characterization of this model was not
      performed comprehensively since advanced analysis of biopsies were omitted. Furthermore,
      analyses performed in previous studies only partially described wound healing processes
      either by insufficient time points for characterization or scarce simultaneous evaluations of
      multiple wound healing modalities. In addition, novel non-invasive imaging methodologies
      including thermography, 3D photography, multispectral imaging, enable more comprehensive
      profiling of the wound morphology.

      The overall aim of this study is to develop a standardized model to temporarily and locally
      induce a skin trauma to investigate wound healing and monitor wound closure. This clinical
      model will enable future application as proof-of-pharmacology and proof-of concept studies as
      well as drug profiling in early drug development programs. More specifically, the objective
      of the trial is to explore and characterize the induction of well-defined skin trauma and
      natural wound healing process over the course of the different phases using a battery of
      dermatological assessments after skin punch biopsies in healthy volunteers. Furthermore,
      safety and tolerability will be assessed.

      Characterization and monitoring of wound healing effects following skin punch biopsies will
      be performed by means of biophysical, biochemical, imaging, clinical parameters and subject
      reported outcomes.

      Objective(s) Primary Objective

        -  To characterize and monitor wound healing after a standardized, induced skin trauma
           Secondary Objectives

        -  To evaluate safety and tolerability of biopsy-induced skin trauma Design This is an
           observational, single center, single arm study. Treatments Biopsy sites will be treated
           by secondary healing intention with a non-stick gauze dressing followed by no treatment
           after 48h.

      Investigational drug Not applicable Comparative drug No comparative drug will be used in this
      study. Study periods The total duration of the study will be approximately 14 weeks: 4 weeks
      for screening and 10 weeks of observation. Subjects will visit CHDR 14 times.

      Subjects / Groups A total of 18 healthy volunteers are planned to be enrolled. The study will
      entail 1 cohort with a randomized repeated biopsy collection time. Three skin punch biopsies
      (3 mm) of the lower back will be taken from each volunteer on day 0, with a distance of
      approximately 3-5 cm in between. All biopsy lesions will be treated with a gauze dressing
      (Jelonet®, paraffine gauze + Tegaderm®) for 48h after which the gauze is removed. Hereafter,
      the biopsy lesions will remain untreated. One biopsy sample taken on day 0 will serve as a
      baseline measurement for the repeated samples regarding the histology, immunohistochemistry,
      and RNA sequencing (RNA-seq) or real-time reverse transcription polymerase chain reaction
      (qRT-PCR) assessments.

      Repeated biopsies of the same location as on day 0 will be taken on day 7, 14 or 21 (biopsy
      lesion and day randomized), and day 28, 42 or 56 (biopsy lesion and day randomized) for all
      subjects. The observation biopsy (biopsy lesion randomized) will serve as primary biopsy and
      followed for all measurements. All repeated biopsy lesions will also be treated with a gauze
      dressing (Jelonet®, paraffine gauze + Tegaderm®) for 48h after which the gauze is removed and
      observation commences.

      Cohort: 1 Observation period (day 2 - day 70): 3 biopsies taken on day 0

        -  1 repeated biopsy taken on day 7, 14 or 21 (randomized)

        -  1 repeated biopsy taken on day 28, 42 or 56 (randomized)

        -  1 target (primary) biopsy for observation without re-excision Number of subjects: 18

      Inclusion criteria

      Eligible subjects must meet all of the following inclusion criteria at screening:

        1. Healthy subjects, 18 to 30 years of age (inclusive). The health status is verified by
           absence of evidence of any clinical significant active or uncontrolled chronic disease
           following a detailed medical history, a complete physical examination including vital
           signs, blood sampling of hematology, chemistry, and virology, urinalysis, urine drug and
           cotinine testing, and alcohol breath testing. In the case of uncertain or questionable
           results, tests performed during screening may be repeated before randomization to
           confirm eligibility or judged to be clinically irrelevant for healthy subjects.

        2. Body mass index (BMI) between 18 and 30 kg/m2, inclusive

        3. Fitzpatrick Skin type I-II (Caucasian type).

        4. Eligible lower back to perform biopsies (no excessive hair growth, no local skin
           disorder)

        5. Willing to give written informed consent and willing and able to comply with the study
           protocol.

      Exclusion criteria

      Eligible subjects must meet none of the following exclusion criteria at screening:

        1. History of pathological scar formation (keloid, hypertrophic scars)

        2. Any form of body modification of the lower back hindering biopsy collection of unaltered
           skin (e.g. tattoos, piercings, implants)

        3. Any disease associated with immune system impairment, including auto-immune diseases,
           HIV and transplantation patients.

        4. Requirement of immunosuppressive or immunomodulatory medication, including
           glucocorticoids, non-steroid anti-inflammatory drugs (NSAIDs), and chemotherapeutic
           drugs within 30 days prior to enrollment or planned to use during the course of the
           study.

        5. Have any current and/or recurrent pathologically, clinical significant relevant skin
           condition.

        6. Use of topical medication (prescription or over-the-counter (OTC)) within 30 days of the
           start of the study.in local treatment area.

        7. Pregnant, a positive pregnancy test, intending to become pregnant, or breastfeeding.

        8. Current smoker and/or regular user of other nicotine-containing products (e.g.,
           patches).

        9. Average consumption of more than 14 units of alcohol per week

       10. Tanning due to sunbathing, excessive sun exposure or a tanning booth within 3 weeks of
           enrollment or planned to do so during the course of the study

       11. Participation in an investigational drug or device study within 3 months prior to
           screening or more than 4 times a year.

       12. Loss or donation of blood over 500 mL within three months prior to screening.

       13. Any (medical) condition that would, in the opinion of the investigator, potentially
           compromise the safety or compliance of the subject or may preclude the subjects'
           successful completion of the clinical trial.

      Concomitant medications No prescription medication or OTC medications (excluding
      multivitamins) will be permitted within 21 days prior to the start of the study, or less than
      5 half-lives (whichever is longer), and during the course of the study. Exceptions are
      paracetamol (up to 4 g/day) in case of local pain. Use of pain medication will be determined
      by the investigator individually. Other exceptions will only be made if the rationale is
      discussed and clearly documented.

      Endpoints

        -  Biopsy biomarkers:

             -  Histology with hematoxylin and eosin (HE) staining

             -  Immunohistochemistry with wound healing related biomarkers (e.g. CD31, collagen I,
                collagen III, aSMA, fibronectin)

             -  RNA-seq or qRT-PCR for wound healing related biomarkers (e.g. VEGFα, TGFβ1, TGFβ2,
                TGFβ3, PDGF, CTGF, TNF, IL-1B, IL-4, GM-CSF, IL-6, IL-10, MMP1, MMP3, OSM, LOX)

        -  Local skin biomarkers for wound healing related biomarkers (e.g. VEGF-A, TNFα, IL-8,
           TLSP, MMP-3, IL-4) by transdermal analysis patch (TAP)

        -  Clinical imaging (e.g. 2D and 3D photography, thermography, laser speckle contrast
           imaging (LSCI), trans epidermal water loss (TEWL), colorimetry)

        -  Clinical evaluation (erythema grading scale, Red-Yellow-Black (RYB) wound assessment
           scale, the Patient and Observer Scar Assessment Scale (POSAS))

        -  Skin microbiome (healthy and biopsy lesions) Tolerability / safety endpoints

        -  Adverse events (AEs)

        -  Local tolerance (erythema grading scale, RYB wound assessment scale, POSAS, NRS pruritus
           and pain) All of above mentioned pharmacodynamic and safety measurements will be
           performed multiple times during the study according to the Visit and assessment
           schedule.

      Sample Size Justification A total cohort size of 18 healthy volunteers will be investigated.
      This is justified since the primary objective is to explore and monitor the wound healing
      model. No formal power calculation was performed given the exploratory character of the
      study.

      Statistical methodology Data listings and averages will be presented for pharmacodynamics and
      safety measures.

      Given the exploratory character of the study, pharmacodynamic endpoints will be primarily
      analyzed using descriptive statistics. All pharmacodynamic endpoints will be summarized (mean
      and standard deviation of the mean, median, minimum and maximum values) by time, and will
      also be presented graphically as mean over time, with standard deviation as error bars. Both
      Nominal results, and log-transformed results and change from baseline results will be
      utilized in all data summaries. All categorical pharmacodynamic endpoints will be summarized
      by frequencies.
    

Intervention name(s): Observation of wound healing
Intervention type(s): Other
Intervention description(s): Observation of wound healing after skin biopsy
Allocation: Randomized
Intervention model: Single Group Assignment
Intervention model description: A single-arm, observational study
Masking: None (Open Label)
Primary purpose: Diagnostic