Breanne Muratori (Dr. Riyi Shi, advisor) will present "Acrolein as an exogenous factor contributing to neuropathic pain after SCI."

Abstract: 

Neuropathic pain (NP) is a debilitating consequence of spinal cord injury (SCI), which is resistant to current analgesic therapies and is capable greatly degrading the quality of life for SCI victims beyond paralysis.  The mechanisms of NP have been widely investigated but are still not well understood.  Although most research has been focused on the endogenous causality, it is possible that external factors may also contribute to NP which could give insight to the pathogenesis and persistency of NP after SCI.  There have been several studies linking cigarette smoking, which is a known serious threat to human health, to an increase in NP in SCI patients, but no animal study has been attempted to study this further.  Acrolein, a neurotoxin present in high quantities in cigarette smoke, has been shown in several animal studies to exist endogenously in elevated concentrations in the days to weeks after SCI and also plays a critical role in the degradation of lipids, DNA, and proteins, and consequently, the functionality of neurons in the CNS after injury.  In addition, acrolein has been shown to be involved in pathogenesis of NP post SCI.  Previous studies with FDA-approved acrolein scavengers have shown that these agents have a neuroprotective effect after SCI in rats by increasing motor function and decreasing NP.  In the current study, the inhalation of acrolein at a level equivalent to that emitting from tobacco smoke was shown to exacerbate NP behaviors by up to 60% over the course of two weeks in rats post-SCI.  After cessation of acrolein inhalation, pain thresholds returned to the baseline level.  The increase in pain coincided with an up-regulation of the transient receptor potential ankyrin-1 (TRPA1) mRNA expression in the spinal dorsal horn and DRG of animals.  TRPA1 is a nociceptor on c fibers of sensory neuron, for which acrolein is a direct agonist.  Further, an increase in an acrolein metabolite, 3-HPMA, in urine was shown during the inhalation period, indicating a systemic accumulation of acrolein.  This data indicates that cigarette smoke can contribute to neuropathic pain after SCI and that taking measures to reduce smoke-borne acrolein could mitigate post SCI pain.  Additionally, and perhaps more importantly, these results further support the mechanistic hypothesis for a key role of acrolein, from both endogenous and exogenous sources, in the genesis NP after SCI.  The ability of acrolein to up-regulate and activate TRPA1 channels indicates that acrolein is a multiple threat in propagating NP, increasing not only activation, but also the sensitivity of TRPA1 to acrolein.  Taken together, these data suggest that acrolein may be a novel and effective therapeutic target to alleviate neuropathic pain resulting from both endogenous and exogenous factors after SCI. 

Rui Li (Dr. Ji-Xin Cheng and Dr. Craig Goergen, advisors) will present "Assessing breast tumor margin by multispectral photoacoustic tomography."

Abstract:

Each year, there are ~240,000 new cases of breast cancer, 70% of which undergo breast-conserving surgery, or lumpectomy.  Due to a lack of a rapid and highly sensitive tool for intraoperative margin assessment, 20-40% of the patients require a second or even a third surgical operation to completely remove all of the tumor tissue.  Such problems cause additional surgical expense as well as the emotional distress and physical pain on the patients. To effectively reduce the re-operation rate, an intraoperative margin assessment tool with high-speed and high-sensitivity is needed.

The current intraoperative tools for margin assessment include cytological examination, frozen section analysis, intraoperative ultrasound and radio frequency spectroscopy. These tools are either time consuming or lack sufficient sensitivity. Emerging optical technologies, including diffuse reflectance imaging, auto-florescence spectroscopy, optical coherence tomography and spatial offset Raman spectroscopy, have improved the sensitivity but still suffered from long procedure times. This difficulty is an unmet need for an intraoperative device which has 1) high tumor detection sensitivity, 2) short procedure time, 3) more than 2 mm tissue sensing depth, and 4) no need for interpretation from pathologists.

To address this need, we for the first time demonstrated the breast tumor margin assessment with a home-built multispectral photoacoustic tomography system using fat and hemoglobin as contrasts. This system provides ~3 mm tissue depth and ~ 200 μm axial resolutions. The results agreed with the histological findings and 100% sensitivity in margin assessment was accomplished. Our system provides chemical selectivity, sufficient tissue penetration and high imaging sensitivity, thus it offers a compelling way for intraoperative breast tumor margin assessment and shows the promise of clinical translation.

(Available via WebEx meeting in SL220A at IUPUI)

***Bring your lunch to seminar – BMEGSA will provide snacks and drinks***