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| ID | Type | Description | Link |
|---|---|---|---|
| RD001968-01 | Other Grant/Funding Number | VA Merit | |
| 1584038 | Other Identifier | IRB |
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| Name | Class |
|---|---|
| Case Western Reserve University | OTHER |
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Establishing a sensitive, scalable physiological test for neurovascular reflex integrity and investigating whether targeted peripheral neural stimulation can enhance perfusion and vasodilatory responsiveness.
The overarching goal of this project is to define how targeted afferent activation can be used to restore impaired neurovascular reflexes, improve skin perfusion, and ultimately prevent further decline in limb health in Veterans. By integrating functional and structural imaging with neural modulation, this work will establish foundational evidence for diagnostic and therapeutic strategies aimed at early detection of neurovascular decline and prevention of tissue breakdown in both Diabetic Peripheral Neuropathy (DPN) and residual-limb contexts. Furthermore, this work will establish the feasibility of preventing or delaying the mechanical trauma of the insensate distal limb which invariably leads to deep pressure injuries, infections, and amputation in Veterans with DPN. The findings have the potential to transform care by enabling earlier diagnosis, improving neurovascular responsiveness, and optimizing neuromodulation protocols to prevent skin complications, delay progression toward amputation, and improve quality of life in Veterans with DPN or limb loss.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Implanted Neural and Muscular Interface | Experimental | 6 lower limb loss participants who have already been chronically implanted with neural and muscular interfaces to allow for direct stimulation |
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| Peripheral nerve stimulation | Experimental | 30 able body participants and 12 participants with unilateral lower-limb loss with receive peripheral nerve stimulation |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Chronically Implanted Neural and Muscular Interface | Device | The implanted neural and and muscular interface will be used to characterize neurovascular reflex testing (thermal axon reflex & pressure-induced vasodilation) and microvascular imaging using Laser Doppler Flowmetry and PAI. Reflex responses will be evaluated under baseline and stimulation conditions (sham, tonic, biomimetic), with direct stimulation performed by the CFINE cohort for modality comparison. Structural-functional relationships will be modeled by integrating metrics from PAI with reflex outcomes. |
| Measure | Description | Time Frame |
|---|---|---|
| Cutaneous Vascular Conductance | Autonomic reflex testing including thermal axon reflex and pressure induced vasoconstriction will be applied. The cutaneous blood flow in the lower limb will be measured using laser doppler flowmetry. The flux is divided by mean arterial pressure to calculate cutaneous vascular conductance. This provides a physiologically relevant metric of microvascular control by accounting for systemic pressure fluctuations | baseline and visits 1-15 until study completion, average 1 year |
| Vessel Density | Defined as the percentage of tissue volume occupied by vascular structures. The investigators use photoacoustic imaging of microvascular structure to quantify microvascular structural integrity at distal and proximal skin sites. From the reconstructed volumetric data, the investigators will extract the vessel density | baseline and visits 1-15 until study completion, average 1 year |
| Tissue Oxygen Saturation | Tissue oxygen saturation or sO2 will be measured during different conditions of the study such as thermal axon reflex and pressure induced vasoconstriction using reflectance spectroscopy | baseline and visits 1-15 until study completion, average 1 year |
| Mean Vessel Diameter | Calculated from the cross-sectional profiles of resolved vessels obtained from the photoacoustic imaging of microvascular structures | baseline and visits 1-15 until study completion, average 1 year |
| Hemoglobin Oxygenation | From photoacoustic imaging, hemoglobin oxygenation is derived and compared across different study conditions | baseline and visits 1-15 until study completion, average 1 year |
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Inclusion Criteria:
Inclusion Criteria - All Participants:
Inclusion Criteria - DPN Participants:
Inclusion Criteria - Lower Limb Amputees:
Exclusion Criteria:
Exclusion Criteria - All Participants:
Additional Exclusion Criteria - Amputees:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Hamid Charkhkar, PhD | Contact | (216) 791-3800 | 62924 | Hamid.Charkhkar@va.gov |
| Jessica R Jarvela, MS BS | Contact | (216) 791-3800 | 63801 | Jessica.Jarvela@va.gov |
| Name | Affiliation | Role |
|---|---|---|
| Hamid Charkhkar, PhD | Louis Stokes VA Medical Center, Cleveland, OH | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Louis Stokes VA Medical Center, Cleveland, OH | Cleveland | Ohio | 44106-1702 | United States |
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| ID | Term |
|---|---|
| D003920 | Diabetes Mellitus |
| ID | Term |
|---|---|
| D044882 | Glucose Metabolism Disorders |
| D008659 | Metabolic Diseases |
| D009750 | Nutritional and Metabolic Diseases |
| D004700 | Endocrine System Diseases |
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| Peripheral Nerve Stimulation (PNS) | Device | The cutaneous peripheral nerve stimulation interface will be used to characterize neurovascular reflex testing (thermal axon reflex & pressure-induced vasodilation) and microvascular imaging using Laser Doppler Flowmetry and PAI. Reflex responses will be evaluated under baseline and stimulation conditions (sham, tonic, biomimetic). Structural-functional relationships will be modeled by integrating metrics from PAI with reflex outcomes. |
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