Funded Projects

Neck pain is the fourth leading cause of disability and also a significant cause of cervicogenic headaches. Many of the currently available neck pain treatments are invasive with associated risks and complications, particularly because of the complex anatomy. Magnetic resonance guided focused ultrasound, a novel, completely noninvasive technique, can precisely target spinal facet joints to help ameliorate neck pain, potentially transforming the current practices. The goal of this study is to develop a cervical spine-specific device and demonstrate its safety and efficacy on targeting cervical sensory fibers and the third occipital nerve. The results of these studies will provide an understanding on how to best use this technology for chronic neck pain as well as a basis for translation into human use.

Medications have proven to be effective for treating opioid use disorder (OUD). Increasing accessibility to buprenorphine provides an opportunity for many with OUD to benefit from its proven effectiveness. Adherence to medication-based treatments however is low, in part because of the stigma associated with use of this and other effective drugs and as such, leads to inadequate treatment and poor outcomes. This study aims to understand the effects of stigma on patient engagement, retention, and outcomes of buprenorphine treatment. Knowledge drawn from the HIV Stigma Theory and tools developed to reduce HIV associated stigma will be used to assess OUD stigma and to develop interventions to reduce it in the context of buprenorphine treatment. The study findings may provide resources to address stigma and thus maximize treatment adherence among those affected by OUD.

Research on optimal long-term opioid therapy (LTOT) tapering strategies has lagged behind clinical needs. Patients with end-stage renal disease (ESRD) receiving hemodialysis (HD) may be especially vulnerable. This study will adapt the Collaborative Opioid Reassessment Program (CORP) and Cooperative Pain Education and Self-Management (COPES) interventions for patients receiving HD and LTOT and test their effectiveness in a pragmatic sequential multiple assignment randomized trial (SMART) design. Initial randomization will be to compare CORP-supported taper with (CORP-B) and without (CORP) buprenorphine rotation on the six-month composite outcome of LTOT dose reduction and pain response. This design will allow determination of which of the eight adaptive treatment strategies leads to the greatest reduction in six-month opioid dose and pain interference.

Masticatory and spontaneous pain associated with temporomandibular joint disorders (TMJD) is a significant contributor to orofacial pain, and current treatments for TMJD pain are unsatisfactory. Pain-related transient receptor potential (TRP) channels, expressed by trigeminal ganglion (TG) sensory neurons, have been implicated in both acute and chronic pain and represent possible targets for anti-pain strategies. Using bite force metrics, we found TMJ inflammation-induced masticatory pain to be significantly, but not fully, reversed in Trpv4 knockout mice, suggesting the residual pain might be mediated by other pain-TRPs. Our gene expression studies demonstrated that TRPV1 and TRPA1 were up-regulated in the TG in response to TMJ inflammation in a Trpv4-dependent manner. We hypothesize that TRPV1 and TRPA1, like TRPV4, contribute to TMJ pain. Our specific aims will examine the contribution of TRPV1, TRPV4, and TRPA1 to pathogenesis of TMJD pathologic pain including assessment of the role of neurogenic inflammation.

Genomic medicine offers hope for improved diagnostic methods and for more effective, patient-specific therapies. Genome-wide associated studies (GWAS) elucidate genetic markers that improve clinical understanding of risks and mechanisms for many diseases and conditions and that may ultimately guide diagnosis and therapy on a patient-specific basis. Previous phenome-wide association studies (PheWAS) established a systematic and efficient approach to identifying novel disease-variant associations and discovering pleiotropy using electronic health records (EHRs). This proposal will develop novel methods to identify associations based on patterns of phenotypes using a phenotype risk score (PheRS) methodology to systematically search for the influence of Mendelian disease variants on common disease. By doing so, it also creates a way to assess pathogenicity for rare variants and will identify patients at highest risk of having undiagnosed Mendelian disease. The project is enabled by large DNA biobanks coupled to de-identified copies of EHR.

Sickle cell disease (SCD) is an inherited hematologic disorder accompanied by severe pain, inflammation, and vascular injury. We propose that nociceptor activation by ongoing hypoxia/reperfusion (H/R) injury leads to the release of neuropeptides by sensory nerves in the skin, stimulating vascular insult and mast cell activation in SCD. In turn, mast cell tryptase activates protease-activated receptor 2 on sensory nerve endings, resulting in exaggerated neuroinflammation, vascular injury, and central sensitization. Our general hypothesis is that neurogenic inflammation contributes to pain in SCD and that cannabinoids provide analgesia by disrupting neurogenic inflammation and nociceptor sensitization. We also hypothesize that EEG and functional MRI can be used to optimize analgesic treatments in SCD. We propose to use transgenic sickle mice, and individual cells involved in evoking pain, to perform this translational study. A proof of principle study in humans will examine the effect of cannabis on pain in sickle patients.

Despite the pervasive use of opioid analgesics in the dialysis population and the substantial risks they engender, their efficacy is limited in treating common chronic pain conditions. Most patients receiving long-term opioid therapy continue to experience severe pain and functional limitations. To simultaneously address problems related to chronic pain and opioid use in the U.S. hemodialysis population, this study will evaluate tailored patient-centered interventions to manage pain and reduce opioid use. Patients will be assigned randomly to one of three groups over a 12-month study period: 1) pain care management (PCM) versus 2) PCM plus an online pain self-management program (PSM) that incorporates cognitive behavioral training and is delivered during dialysis sessions, versus 3) control with medication review and education. The study will also evaluate the effectiveness of offering buprenorphine by randomly assigning participants in both active treatment arms to being offered buprenorphine rotation versus continued standard opioid taper support without the option of buprenorphine.

The MGH EPPIC-Net hub will utilize two well-established collaborative entities in both patient care and clinical research at the Massachusetts General Hospital (MGH): 1) MGH Division of Pain Medicine and 2) MGH Center for Translational Pain Research. This hub-spoke network at MGH will include four core spokes consisting of both academic centers and community health care organizations, as well as over a dozen spokes that can be recruited as needed based on special requirements of phase II trials and research studies. The responsibilities of this hub-spoke network at MGH include a) coordinating phase II trials/clinical biomarker validation studies; b) recruiting well-phenotyped subjects in a timely manner; c) collecting clinical data and targeted outcome data tailored to meet the needs of each clinical trial/study; and d) maintaining communications within and outside the hub, including the NIH EPPIC-Net.

It is unclear what changes in the brain mediate the development of chronic pain from acute pain and how chronic pain may change responses to opioid reward for the altered liability of opioid abuse under chronic pain. Preliminary studies have found that Dnmt3a, a DNA methyltransferase that catalyzes DNA methylation for gene repression, is significantly downregulated in the brain in a time-dependent manner during the development of chronic pain and after repeated opioid treatment. This project will investigate whether Dnmt3a acts as a key protein in the brain for the development of chronic pain, and whether Dnmt3a could be a novel epigenetic target for the development of new drugs and therapeutic options for the treatment of chronic pain while decreasing abuse liability of opioids.

Chronic pain is a major health burden associated with immense economic and social costs. Predictive biomarkers that can identify individuals at risk of developing severe and persistent pain, which is associated with worse disability and greater reliance on opioids, would promote aggressive, early intervention that could halt the transition to chronic pain. The applicant’s team uncovered evidence of a unique cortical biomarker signature that predicts pain susceptibility (severity and duration). This biomarker signature could be capable of predicting the severity of pain experienced by an individual minutes to months in the future, as well as the duration of pain (time to recovery). Analytical validation of this biomarker will be conducted in healthy participants using a standardized model of the transition to sustained myofascial temporomandibular pain. Specifically the biomarker signature will be tested for its ability to predict an individual’s pain sensitivity, pain severity, and pain duration and will perform initial clinical validation.

Although opioid-based analgesics have been proven effective in reducing the intensity of pain for many neuropathic pain conditions, their clinical utility is grossly limited due to the substantial risks involved in such therapy, including nausea, constipation, physical dependence, tolerance, and respiratory depression. Cumulative evidence suggests that human Mas-related G protein-coupled receptor X1 (MRGPRX1) is a promising target for pain with limited side effects due to its restricted expression in nociceptors within the peripheral nervous system; however, direct activation of MRGPRX1 at peripheral terminals is expected to induce itch side effects, limiting the therapeutic utility of orthosteric MRGPRX1 agonists. This finding led to the exploration of positive allosteric modulators (PAMs) of MRGPRX1 to potentiate the effects of the endogenous agonists at the central terminals of sensory neurons without activating peripheral MRGPRX1. An intrathecal injection of a prototype MRGPRX1 PAM, ML382, effectively attenuated evoked, persistent, and spontaneous pain without causing itch side effects. The goal of this study is to develop a CNS-penetrant small-molecule MRGPRX1 PAM that can be given orally to treat neuropathic pain conditions.

The research team has developed ultrasonic drug uncaging for neuroscience, in which neuromodulatory agents are uncaged from ultrasound-sensitive biocompatible and biodegradable drug-loaded nanocarriers. This project will clinically translate ultrasonic ketamine uncaging for chronic pain therapy. In the UG3 phase, the research team will scale our nanoparticle production processes to human scales and adapt them to pharmaceutical standards. In the UH3 phase, they will complete a first-in-human evaluation of the safety and efficacy of ultrasonic ketamine uncaging by quantifying how much ketamine is released relative to the ultrasound dose and assessing whether the uncaged ketamine can modulate the sensitivity and affective response to pain, in patients suffering from chronic osteoarthritic pain. This project aims to yield a novel, noninvasive, non-opioid therapy for chronic pain that maximizes the therapeutic efficacy of ketamine over its side effects, by targeting its action to a critical hub of pain processing.

TWIK-related spinal cord K+ (TRESK) channel is abundantly expressed in all primary afferent neurons (PANs) in trigeminal ganglion (TG) and dorsal root ganglion (DRG), mediating background K+ currents and controlling the excitability of PANs. TRESK mutations cause migraine headache but not body pain in humans, suggesting that TG neurons are more vulnerable to TRESK dysfunctions. TRESK knock out (KO) mice exhibit more robust behavioral responses than wild-type controls in mouse models of trigeminal pain, especially headache. We will investigate the mechanisms through which TRESK dysfunction differentially affects TG and DRG neurons. Based on our preliminary finding that changes of endogenous TRESK activity correlate with changes of the excitability of TG neurons during estrous cycles in female mice, we will examine whether estrogen increases migraine susceptibility in women through inhibition of TRESK activity in TG neurons. We will test the hypothesis that frequent migraine attacks reduce TG TRESK currents.