Diabetic Foot Ulcer (DFU) Biofilm Infection and Recurrence

Study Overview
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Brief Summary
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Diabetic foot ulcers (DFU) are one of the most common reasons for hospitalization of diabetic patients and frequently results in amputation of lower limbs. Of the one million people who undergo non-traumatic leg amputations annually worldwide, 75% are performed on people who have type 2 diabetes (T2DM). The risk of death at 10 years for a diabetic with DFU is twice as high as the risk for a patient without a DFU. The rate of amputation in patients with DFU is 38.4%4. Infection is a common (>50%) complication of DFU. Emerging evidence underscores the significant risk that biofilm infection poses to the non-healing DFU. Biofilms are estimated to account for 60% of chronic wound infections. In the biofilm form, bacteria are in a dormant metabolic state. Thus, standard clinical techniques like the colony forming unit (CFU) assay to detect infection may not detect biofilm infection. Thus, biofilm infection may be viewed as a silent maleficent threat in wound care.

Detailed Description
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In the current standard of care (SoC), wound closure is defined (FDA) by wound area re-epithelialization without drainage. The investigators' pre-clinical large animal work demonstrates that wounds with a history of biofilm infection may meet above criteria but the repaired wound-site skin is deficient in barrier function. This has led to the concept of functional wound closure wherein the current clinical definition of wound closure is supplemented with a functional parameter - restoration of skin barrier function as measured by low trans-epidermal water loss (TEWL). This study rests on DFU-patient based findings from a NIDDK-DIACOMP funded pilot study (Sen/Gurtner) showing that closed DFU with deficient barrier function are more likely to recur. Biofilm infection as assessed through Scanning electron microscopy and wheat germ aggluttin assay performed on debrided tissue causes faulty re-epithelialization, compromising skin barrier function at the closed wound site. Such defects are caused by biofilm-inducible miRs which silence junctional proteins necessary for skin barrier function. The IRB protocol associated with this study, rests on our novel patient-based observation that in wound-edge tissue catenin delta1/p120 catenin (CTNND1) is suppressed as measured through immunohistochemistry. CTNND1 is an essential regulator of E-cadherin stability which is regarded as a master organizer in epithelial phenotype and plays a critical role in maintaining the barrier integrity of skin. The investigators' prior study identified miR-9 is a biofilm induced microRNA that targets adherens junction protein E-cadherin. The investigators propose that miR-9 can target CTNND1. The validation of miR targeting will be performed quantitative real time PCR, Western blot analyses, Argonaute 2 pull down assay and on bead assay. Thus this proposal, fully based on the study of DFU patients, seeks to conduct a fully powered clinical study testing whether DFU with a history of biofilm infection closes with deficient barrier function (Aim 2). Aim 3 tests whether such functionally deficient wound closure, manifested as high TEWL, is associated with greater wound recurrence. Per FDA, the significance of association studies is heightened by support of a well-founded biological rationale provided by mechanistic studies. This proposal rests on such mechanisms that have been reported by us in pre-clinical large animal studies. A chronic hyperglycemic diabetes increases the risk of developing Alzheimer's disease (AD) and vascular dementia (VaD), both in general and elderly population. With the age-related changes of the skin, there is an increased risk of adverse skin barrier function that is key to wound healing. Other age-related skin conditions, such as reduced water and altered lipid content, and lower production of sebum and natural moisturizing factors of the stratum corneum (SC) may also cause dry skin and itching. These conditions together with reduced immune responses, cause aging skin to be more susceptible to infections4. In light of these facts, there is paucity in studies that investigate the mechanism of how compromised skin barrier function plays a role in wound healing outcomes among Alzheimer's Disease and Related Dementias (AD/ADRD) patients. The primary parent study will address molecular mechanisms implicated in biofilm-induced loss of skin epithelial barrier integrity in DFU patients. Within the parent study, an additional cohort of patients with a chronic wound that are diagnosed with Alzheimer's Disease and Related Dementias (AD/ADRD) will be studied to better understand the similarities and differences in molecular mechanisms and wound healing trajectory between this group and the parent cohort.

Official Title
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Diabetic Foot Ulcer (DFU) Biofilm Infection and Recurrence

Conditions
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Wound Infection, Wound Heal, Foot Ulcer, Ulcer Foot, Diabetic Foot, Diabetic Foot Infection

Intervention / Treatment
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* Procedure: Observation of wound infection and time to wound closure
* Device: Pericam PSI-NR Laser Speckle imaging


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or Female, Age ≥ 18 Willing to comply with protocol instructions, including all study visits and study activities. Patient with an open Diabetic Foot Ulcer Adequate arterial blood flow as evidenced by at least one of the following (for wounds below the knee): TcOM >30 mmHg Ankle-brachial index ≥0.7-1.20 Toe pressure > 30 mmHg TBI > 0.6 mmHg Exclusion Criteria: Individuals who are deemed unable to understand the procedures, risks, and benefits of the study. Wounds closed or to be surgically closed by flap or graft coverage Subjects with marked immunodeficiency (HIV/AIDS, or on immunosuppressive medications. TcOM < 30mmHg Diabetics with a hemoglobin A1c > 12 within 3 months prior to enrollment Subject with autoimmune connective tissue disease Ulcer size and location that does not allow the TEWL measurement per SOP Pregnant women Prisoners Unable to comply with study procedures and/or complete study visits AIM 4 Inclusion Inclusion Criteria: Male or Female, Age ≥ 18 with a clinical diagnosis of Alzheimer's Disease or Related Dementias (AD/ADRD), or any similar cognitive impairment. An available Legally Authorized Representative (LAR), as needed, to provide consent Willing to comply with protocol instructions, including all study visits and study activities. Clinically diagnosed with diabetes as defined by the American Diabetes Association Chronic would defined as any ulcer that has been open for ≥ 30 days Adequate arterial blood flow as evidenced by at least one of the following (for wounds below the knee): TcOM >30 mmHg Ankle-brachial index ≥0.7-1.20 Toe pressure > 30 mmHg TBI > 0.6 mmHg AIM 4 Exclusion Exclusion Criteria: Wounds closed or to be surgically closed by flap or graft coverage Subjects with marked immunodeficiency (HIV/AIDS, or on immunosuppressive medications. TcOM < 30mmHg Diabetics with a hemoglobin A1c > 12 within 3 months prior to enrollment Subject with autoimmune connective tissue disease Ulcer size and location that does not allow the TEWL measurement per SOP Pregnant women Prisoners Unable to comply with study procedures and/or complete study visits

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Diabetic Foot Ulcer parent study<br>405 clinically diagnosed Diabetic Foot Ulcer (DFU) patients who are suspected to be infected will be recruited . Wound swab for culture obtained. Baseline digital imaging of target wound(s). SF-12 Health survey, Visual Analogue Pain scale, Cardiff wound impact questionnaires. Wound site evaluation including TcOM/TBI/ankle brachial index (ABI) will be completed for subjects with wounds below the knee, if not already completed per standard of care within the previous 12 months. Hemoglobin A1c point of care testing will be drawn for diabetic subjects who do not have an A1c available within 90 days prior to enrollment; 3mm biopsy tissue or debrided tissue will be collected. Ideally, two tissue samples will be obtained; the subject's medical records will be reviewed and followed for up to 16 weeks or until their wound has closed, whichever comes first. The research staff will also call the patient or care facility as needed to check for wound closure. | Procedure: Observation of wound infection and time to wound closure<br>* Observational: collecting data on length of time to wound closure<br>|
| Imaging sub study- 30 subjects<br>All of the above items will be performed in this arm in addition to the below: Wound perfusion will also be measured by laser speckle imaging (LSI) using the Pericam PSI-NR instrument (Perimed Inc.). PeriCam PSI is a non-invasive non-contact device providing two-dimensional imaging of peripheral tissue blood perfusion. Reduced blood flow may lead to insufficient tissue oxygenation and, thus, assessment of peripheral vascular function has several clinical applications. The PeriCam PSI System is FDA 510(k) (#K063586) approved instrument imaging of peripheral tissue blood perfusion. The additional Pericam imaging for perfusion will be performed only in a small pilot cohort of n=40 patients at an IU site to compare this imaging modality with established modalities such as TcOM/TBI/ABI measurements performed within this study. | Procedure: Observation of wound infection and time to wound closure<br>* Observational: collecting data on length of time to wound closure<br>Device: Pericam PSI-NR Laser Speckle imaging<br>* non-invasive non-contact device providing two-dimensional imaging of peripheral tissue blood perfusion. Reduced blood flow may lead to insufficient tissue oxygenation and, thus, assessment of peripheral vascular function has several clinical applications.<br>|
| Alzheimer and/or related dementia<br>All items in the group: Diabetic Foot Ulcer Parent study will be performed plus: 15 patients that currently have an open chronic wound and are clinically diagnosed with Alzheimer's Disease or Related Dementias (AD/ADRD) will be recruited for this additional cohort. | Procedure: Observation of wound infection and time to wound closure<br>* Observational: collecting data on length of time to wound closure<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Aim 1 | Determine how biofilm-induced DFU tissue microRNA's disrupt barrier function of the repairing DFU | 16 weeks | 
| Aim 2 | Test the incidence of wound biofilm infection at initial visit and test its association with deficient skin barrier function at the closed DFU-site | 16 weeks | 
| Aim 3 | Test whether closed DFU with deficient barrier function is associated with higher rate of recidivism | 12 weeks | 
| Aim 4 | Identify the predictors and patterns of wound healing outcomes and wound recurrences among AD/ADRD and non-AD/ADRD patients | 28 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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foot ulcer, diabetic foot, wound infection, diabetic foot ulcer