Low back pain is an endemic problem and is the second most common reason that Americans go to see their doctor, second only to the most common cold and the flu. Low back pain is also the second most common illness-related reason given for a missed workday and the most common cause of disability. In recent years, a body of research has suggested a possible role of injury-induced inflammation in low back pain caused by damaged and degenerating intervertebral discs. As such, the use of fluoroscopy-guided lumbar epidural injections of steroids to reduce the local chemo-inflammatory response has increased dramatically since their inception as a treatment in the 1950s. However, the risks of epidural injections include, but are not limited to, epidural hematoma, epidural infection, nerve root injury, dural puncture, air embolism and vasovagal syncope. Moreover, the epidural injection is technically demanding. It is usually performed under x-ray by doctors with special training. When a patient gets an appointment, the pain is likely in a more subacute or chronic state. Therefore, a cost-effective treatment for acute/chronic back pain is of great importance. Our application proposes a novel treatment by linking nano-fullerene to cFLFLF in order to specifically target activated neutrophils that migrate into the disc herniation site and treat acut back pain via peripheral vein injection, which is not technically demanding and could be performed by a nurse. Nano-fullerene, which has potent anti-oxidative and anti-inflammatory properties, without specific biological target could not only reduce hyperalgesia induced by the extrusion of nucleus pulposus tissue from herniated discs, but also eliminate the side effects associated with standard biological target-oriented drug molecules. However, an effective delivery system is needed to overcome its highly hydrophobic properties to specifically target the site of injury. The overall hypothesis of this study is that the activated neutrophils expressig formyl peptide receptor (FPR) will bind to proteolytically resistant synthetic peptide cFLFLF and that together they will infiltrate and accumulate into the site of inflammation in the herniated dic. Linking nano-fullerene to a cFLFLF (cFLFLF-PEG-fullerene) will ensure event-specific temporal and spatial delivery of the anti-inflammatory agent to the site of injury via systemic injection to treat the pain caused by excessive inflammation in and around herniated discs.
In Aim 1 of the proposed study, we will characterize the infiltration of activated neutrophils into an acute disc herniation using neutrophil-specific small molecule imaging agents and immunohistology. The imaging signal will be validated using FPR knockout mice. The neutrophils and macrophages will be analyzed for expression and quantification of FPR and for the quantification of injury.
In Aim 2, we will characterize the inhibitory effect of aqueous suspensions of nano-fullerene on local inflammation induced by disc herniation in vitro and in vivo.
In Aim 3, we will synthesize cFLFLF-PEG-fullerene and evaluate its systemic vs. local delivery to a site of inflammation in a mouse radiculopathy model;we will also assess injury site target systemic delivery vs. non- specific systemic delivery using wild type and FPR knockout mice in a disc degeneration model induced by needle puncture. This study will provide useful insights into a novel cost-effective therapeutic strategy for acute and chronic back/neck/leg pain involving systemic injection of non-protein, nano-structured, biocompatible fullerene conjugated with cFLFLF, a neutrophil-specific binding peptide. This method is much more cost- effectiveness compared to epidural steroid injection.
Low back pain is an endemic health problem and is the second most common reason Americans see their doctor, second only to colds and flu. Current treatments for low back pain, such as surgery or treatment with epidural injections of steroids, has many risks, thus there is an immense need for new treatment approaches. This study aims to develop a novel and highly efficient method of delivering an anti-inflammatory agent to the site of disc damage.