Developing Strategies for Effective Debridement in Patients for Venous Leg Ulcers

Chronic non-healing venous leg ulcers (VLUs) have an intrinsic healing impairment that is
associated with dysfunctional gene expression patterns. We have shown that tissue from the
non-healing edge of chronic VLUs exhibits characteristic histopathology including epidermal
hyperproliferation, dermal fibrosis, accumulation of intracellular pro-collagen and
dysregulation of genes involved in epidermal differentiation, migration and proliferation. We
have demonstrated that biopsies taken from the non-healing edges of VLUs before and after
debridement have distinct morphologies and distinguishable gene expression patterns,
providing the biological basis and justification of debridement. These observations are
supported by the findings that primary cells grown from tissue biopsies before and after
debridement also have distinct and typical genomic patterns, with cells from pre-debridement
edge biopsies exhibiting a non-healing phenotype as evidenced by loss of migration and loss
of ability to respond to growth factor stimuli. Moreover, we used a genomic approach in a
clinical trial to determine mechanism of action of cell based therapy in patients with VLU
and identified a specific set of genes responsible for therapeutic reprogramming that shifts
non-healing ulcer into acute wound-like healing VLU.

Taken together, preliminary data suggests a loss of healing potential, prior to debridement
which is distinct from cells taken from a post-debridement biopsy, which show an ability to
migrate and respond to growth factors. Limited clinical data suggests a positive response in
wound size reduction in VLUs following wound debridement, but debridement is not performed,
routinely, consistently and systematically and thus is often not considered standard of care
for VLUs. Furthermore, in contrast to the edge of diabetic foot ulcers (DFUs) where a
possible margin of debridement maybe visually delineated by callus at the wound edge, VLUs
lack callus and therefore it is much more difficult to assess to what extent debridement
should be performed, thereby questioning its overall benefit and efficacy. Therefore, we
hypothesize that genes (their transcription level or protein patterns) can be utilized to
guide wound edge debridement in patients with VLUs and further that such guided debridement
will improve healing outcome in patients suffering from chronic non-healing VLUs. Moreover,
we propose to use genomic profiles to further advance and guide development of PCR-based
approach or immunostains that can serve as a simplified diagnostic test to identify
debridement margin and non-healing VLUs tissue.

Inclusion Criteria:

1. >18 years of age

2. Conformation of venous disease by non-invasive venous studies with either
Doppler-confirmed venous reflux, or having ≥ 2 clinical characteristics of venous
insufficiency (varicose veins, lipodermatosclersosis, venous dermatitis, atrophie
blanche, edema)

3. have a venous ulcer between the knee and ankle, at or above the malleolus

4. wound size would be greater than or equal to 5cm2 in area without exposed tendon,
muscle or bone

5. wound duration of at least 6 months

6. VLU containing yellow/white slough with or without fibrous/scar tissue and/or
non-viable tissue

7. ability of subject to tolerate limb compression bandage

Exclusion Criteria:

1. history of diabetes mellitus and a HbA1c > 12% (obtained within past 6 months)

2. Ankle brachial index(ABI) less than 0.80

3. any active cancer other than a nonmelanoma skin cancer; any previous cancer must be in
remission for at least 5 years

4. suspicion of malignancy within VLU

5. life expectancy <6 months

6. history of kidney disease and creatinine greater than 2.0 (obtained within past 6
months)

7. history of liver disease and liver function test (ALT, AST, ALK PHOS, and bilirubin)
>2x upper limit of normal (obtained within past 6 months)

8. requirement for long-term systemic corticosteroids or immunosuppressive therapy, or
history of corticosteroid or immunosuppressive use in the 4 weeks prior to study entry

9. history of immunodeficiency

10. ulcers due to none venous etiology and leg ulcers associated with mixed etiology

11. Untreated osteomyelitis

12. Hepatitis

13. acute deep venous thrombosis

14. allergy to lidocaine and/or epinephrine

15. Subject's inability to successfully tolerate compression therapy that is changed
weekly

16. Skin ulcer previously treated within the last 4 weeks with biologic therapies (e.g.
cell therapy or growth factors)

17. if currently incarcerated

18. known pregnancy