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Major areas of research in the department include:

  • Neurobiology of Pain: Basic mechanisms by which pain signals are initiated, transduced and modulated in sensory pathways
  • Organ Injury and Repair: Basic mechanisms resulting in pulmonary and systemic injury following inhalation of toxic gases and pathogens, ischemia-reperfusion, organ transplantation and trauma.

The division's current projects, organized in alphabetical order by PI:

Aftab Ahmad, Ph.D.

Extracellular RNA as Therapeutic Target after Toxic Chemical Inhalation

The purpose of this U01 is to develop specific medical countermeasures that can be used to rescue victims of civilian disaster, acts of terrorism, and military attack after exposures to toxic inhaled gases. This proposal is aimed at testing certain rescue agents after inhalation of toxic gasses like sulfur mustard.

Exposure to toxic inhaled chemicals like sulfur mustard (SM) can cause injuries to the respiratory system, eyes, skin and also frequently leads to death. The pathogenesis of sulfur mustard-induced injury is incompletely understood and a search for effective treatment regimens has been a challenge. SM-induced toxicities activate several pathways that include the coagulation and inflammatory pathways. Extracellular RNA (exRNA) and hypoxic signaling events drive several factors implicated in these pathways. This proposal focuses on understanding the role of extracellular RNA and associated inflammatory pathways in SM-induced injuries. These studies will be carried out using CEES, a surrogate of sulfur mustard as well as sulfur mustard. We hypothesize that CEES/SM exposures release exRNA that causes activation of the coagulation pathway and also inhibition of HIFs that in turn activate proinflammatory pathways. And that blocking of exRNA and stabilization of HIFs can alleviate toxicity and lung injury. Results of the proposed research will help identify treatment options for sulfur mustard exposures as well as other potentially toxic chemical inhalations associated with increased exRNA and metabolic poisoning.

Hypoxic Factors in Pulmonary Hypertension

Severe pulmonary hypertension is an irreversible disease that causes morbidity and mortality. The project investigates the role of a hypoxic factor, HIF-2alpha in causing pulmonary hypertension and proposes to block this factor and associated pathway as a therapeutic intervention. Proposed studies could lead to new targets for therapy of pulmonary hypertension and a better understanding of the disease process.

Severe pulmonary hypertension is a progressive and irreversible disease that often leads to mortality due to right heart failure. The pathogenesis of pulmonary hypertension involves proliferation of cells, including endothelial cells (intimal remodeling), in the vessel walls of pulmonary arteries resulting in remodeling and pulmonary hypertension. Several factors implicated in the remodeling process are driven by hypoxia. One mechanism by which cells respond to hypoxia is by stabilization of hypoxia-inducible transcription factors (HIFs), HIF-1alpha and HIF-2alpha. Independent studies suggest that both HIF-1alpha and HIF-2alpha are important mediators in PH. However, recent investigations have reported a marked increase in HIF-2alpha gene locus polymorphism in individuals adapting to high altitudes, suggesting a role of HIF-2alpha in PH. Mechanism by which HIF-2alpha influences pulmonary vascular remodeling and PH, independent of HIF-1alpha is not known. This proposal is focused on understanding the role of HIF-2alpha and its pathways in the pathogenesis of pulmonary hypertension. We have recently identified a new pathway, the HIF-2alpha-A2A receptor pathway, by which HIF-2alpha can promote endothelial proliferation, independent of HIF-1alpha. We hypothesize that hypoxia increases endothelial proliferation and vascular remodeling through a HIF-2alpha and A2A receptor-dependent mechanism and that this is an important step in the pathogenesis of PH. Additionally, we have also identified HIF-1alpha in smooth muscle cell proliferation, independent of HIF-2alpha. The proposed studies are divided into three aims. Aim 1 will elucidate mechanisms by which hypoxia and HIFs influence endothelial growth using cultured primary pulmonary endothelial cells as well as endothelial cells derived from hypertensive rats. The second aim will be used to test the hypothesis that inhibition or knockdown of HIFs, particularly HIF-2alpha will limit vascular remodeling and PA pressures in a rat model of PAH. The third aim will test whether inhibition or knockdown of A2A receptor, a downstream transcriptional target of HIF-2alpha, can mitigate remodeling and PA pressures in a rat model of PAH. The in vivo aims will investigate effects using both a prevention model and a rescue model. Results of the proposed research will help provide insights into hypoxic pathways that influence pulmonary vascular remodeling and offer alternative targets for treatment of PH.

Ryan Almeida, M.D.

High-Frequency Nerve Block for Post-Amputation Pain: A Pivotal Study (Doc#003-0001)

Jennifer DeBerry, Ph.D.

Optogenetic Dissection of the Functional Properties of Bladder Afferent Populations

Interstitial cystitis (IC) and overactive bladder (OAB) are distinguishable, debilitating, chronic urological disorders characterized by bladder hypersensitivity. The symptoms of IC and OAB, which include altered micturition patterns with or without pain, are difficult to manage. The objective of this research is to physiologically dissect the roles of bladder afferent subpopulations in bladder homeostasis and their contributions to pathological sensory changes (e.g., increased urinary frequency, persistent pain) as a first step in development of targeted therapeutic interventions that can be tailored to different bladder pathology depending on the underlying disease mechanism.

Interstitial cystitis (IC) and overactive bladder (OAB) are chronic urological disorders characterized by urinary urgency and increased micturition frequency. A defining characteristic of IC that distinguishes it from OAB is the presence of pelvic/suprapubic pain that worsens as the disease progresses. Because visceral innervation is unique (organs are innervated by two nerves) and noxious visceral stimuli are unlike noxious cutaneous stimuli, mechanisms of bladder hypersensitivity differ from those of cutaneous hyperalgesia. Mechanical and/or chemical hypersensitivity of the bladder largely underlies the symptoms experienced by both IC and OAB patients. Yet, because the defining combination of symptoms (urgency and frequency with or without pain) for each cohort differs, and because symptoms arise from a common global population of bladder afferents, selective changes in transduction must occur either within afferent subpopulations, or among the central pathways engaged by afferent subpopulations, or both. These phenomena are poorly understood. Heterogeneous bladder neuronal subpopulations with lightly myelinated or unmyelinated peripheral fibers (A? - and C-fibers, respectively) convey information about multiple processes, including homeostatic monitoring (metaboreceptors) and detection of potentially damaging stimuli (nociceptors). Some fibers exhibit chemosensitivity, and most respond to mechanical stimuli, although some may acquire mechanosensitivity only during pathological conditions. We propose to use transgenic mouse lines expressing the light-gated ion channel, channelrhodopsin-2 (ChR2), in specific subsets of bladder afferents to address their respective contributions to the cardinal symptoms of IC and OAB. We hypothesize that subpopulations of bladder afferents contribute uniquely to micturition processes and nociception. We will test this hypothesis by studying afferent subpopulation contributions: 1) using an ex vivo preparation to functionally evaluate intrinsic and mechanical, chemical, and light-evoked response characteristics, 2) to the expression of in vivo micturition and nociceptive reflexes, and 3) to th activation of neurons receiving bladder afferent input in distinct regions of the spinal cord.

Role of growth factors (ARTN, GDNF) in TRPA1-dependent mechanisms of chemotherapy-induced peripheral neuropathy

Jianguo Gu, Ph.D.

Mechanism of Nociception Induced by Innocuous Cold in Trigeminal System

Many clinical conditions including dental procedures, traumatic injury, tumors, and chemotherapy can result in chronic trigeminal nerve injury and degeneration. These often lead to the development of trigeminal neuropathic pain that manifests cold allodynia and hyperalgesia in orofacial regions. The trigeminal neuropathic pain constitutes a huge health problem because of its severity, special location, and resistance to conventional treatment. This project will use advanced neurobiological approaches and animal models to identify molecular and neuronal mechanisms underlying orofacial cold allodynia and hyperalgesia. The accomplishment of the Aims proposed in this project will lead to novel therapeutic targets for treating trigeminal neuropathic pain that manifests cold allodynia and hyperalgesia.

Orofacial pain disorders encompass a wide range of conditions including trigeminal neuralgia, reflex sympathetic dystrophy (RSD) of the face, temporomandibular joint disorders, periodontal pain, burning mouth syndrome, dental surgical pain, head and neck cancer pain, pain due to oral infections, and other neuropathic and inflammatory pain conditions. One common symptom in many chronic orofacial pain conditions is cold allodynia/hyperalgesia, the excruciating painful sensation induced by cooling temperatures that would normally produce innocuous or mild painful cooling sensation. Unfortunately, the current clinical treatments are unsatisfactory for this chronic orofacial pain condition. This is largely due to the poor understanding of mechanisms for controlling cold sensitivity in trigeminal sensory system. We have recently accumulated evidence suggesting that cold sensitivity of nociceptive cold- sensing neurons may largely depend on low-threshold voltage-gated K+ channels (KLT), a subclass of voltage-gated K+ channels that are activated near resting membrane potentials. Furthermore, we found that pharmacologically potentiating KLT channels reversed orofacial cold allodynia/hyperalgesia. In this renewal application, the overall objectives are to study the role of KLT channels in controlling cold sensitivity of nociceptive cold-sensing trigeminal neurons under both physiological and trigeminal neuropathic conditions, and to explore therapeutic use of KLT channel potentiators for treating orofacial cold allodynia and hyperalgesia. Advanced neurological techniques including patch-clamp records and calcium imaging together with other approaches including immunostaining and novel animal models will be used in this project. By accomplishing our goal, we will have identified novel therapeutic targets for treating some intractable orofacial pain conditions.

Cellular and Ion Channel Mechanisms Underlying the Sense of Light Touch in Mammal

The sense of light touch enables tactile discrimination of shapes, texture, vibration and spatial details, and is indispensable in daily life, yet scientific knowledge about how mammals can sense light touch remains lacking at a cellular and molecular level. The expected outcomes of the proposed research will uncover cellular and ion channel mechanisms underlying mechanical transduction for light touch. Because light touch dysfunctions such as the loss of touch sensitivity and the pain induced by light touch are common clinical problems seen under pathological conditions such as diabetes, chemotherapies and other diseases, understanding cellular and molecular mechanisms of light touch may help us better understand the physiopathology of these sensory dysfunctions, and may further lead to new strategies for preventing or treating the sensory dysfunctions.

The sense of light touch is critically important for daily life but this important sense can be altered to result in sensory dysfunctions such as tactile anesthesia and mechanical allodynia under pathological conditions. How mammals can sense light touch has been one of the biggest mysteries in science. This lack of knowledge prevents development of potentially effective approaches for preventing or treating mechanical sensory dysfunctions. Our long-term-goal is to uncover the cellular and molecular mechanisms underlying the sense of light touch in mammals. As the first stage of our long-term goal, the overall objective of this application is to study mechanisms underlying mechanical transduction of Merkel cell-neurite complex, a sensory structure essential for sensing light touch in mammals. Our central hypothesis is that Merkel cells are mechanical transducer cells that express mechanically activated ion channels (MA) and that activation of these channels triggers Merkel cells to fire action potentials and release excitatory transmitters. This hypothesis is based on ou preliminary results obtained by using our recently developed patch-clamp recordings from Merkel cells situated in whisker hair follicles (Merkel cell in situ patch-clamp technique). This innovative technique has, for the first time, led us to successfully record MA currents from Merkel cells. We have further discovered that Merkel cells in situ fire action potentials in response to mechanical stimulation. Our unique expertise of Merkel cell in situ patch-clamp recording technique places us at an advanced position to test the hypothesis with the following specific aims: 1) Elucidate ionic mechanisms of MA currents that excite Merkel cells in situ and characterize Merkel cell MA channel properties; 2) Identity ion channels that encode mechanical activity in Merkel cells; and 3) Delineate the mechanisms underlying the transmission of mechanical activity by Merkel cells. The outcomes of the above investigations will provide scientific knowledge about the sense of light touch at a cellular and molecular level. The study may have clinical implications ranging from sensory dysfunctions seen in diabetes and other disease conditions to Merkel cell malfunctions such as Merkel cell carcinoma.

Kevin Harrod, Ph.D.

Targeting MMP9 to Improve Outcomes in Serious Influenza Infections

Influenza infection is still an important public health concerns despite the availability of vaccines. As influenza viruses undergo high rates of mutation enabling them to evade protection from natural and vaccine-mediated immunity, new drugs are urgently needed for serious influenza infections. Herein a new class of drug will be tested for its efficacy to reduce influenza-associated mortality and morbidity in two animal species to satisfy the FDA "Two Animal Rule".

Influenza infection remains an enormous public health concern despite the availability of vaccines and worldwide surveillance. The high mutation rates of influenza A viruses (IAVs) enable the viruses to evade natural and vaccine-mediated immunity. Also, current anti-viral therapies do not prevent IAV-related deaths when there is a delay in initiating treatment. Thus, new therapeutic options for treating influenza disease are an immediate public health priority. Our pilot studies identify MMP-9 as an attractive IAV therapeutic target. MMP- 9 is strikingly upregulated in plasma samples from human subjects infected with seasonal and H1N1 IAV and in lungs from mice infected with H1N1 IAV. In mice, Mmp-9 increases IAV-associated mortality and late-stage lung inflammation and late-stage lung viral burdens. We proposed to test the therapeutic efficacy of a "re- purposed" therapeutic candidate (ADZ1236) that selectively and potently inhibits MMP-9 activity in IAV infections in two species in three integrated and highly collaborative aims. Aim 1 will test the therapeutic efficacy of AZD1236 therapy in mice infected with BL2 H1N1 IAV. AZD1236 will be tested in mice alone and in combination with a clinically-used antiviral agent (the neuraminidase inhibitor, oseltamivir). A delayed initiation of treatment approach will be optimized to model "rea-world" treatment scenarios for serious IAV infections. Aim 2 will identify the mechanisms by which Mmp-9 promotes (and AZD1236 limits) serious IAV infections in mice. We will study H1N1-infected WT vs. Mmp-9-/- mice and Mmp-9 bone marrow chimeric mice and use in vitro approaches to test our hypothesis that Mmp-9 promotes adverse outcomes in IAV disease by cleaving host or viral proteins. These Mmp-9 substrates will be identified. Aim 3 will test the therapeutic efficacy of AZD1236 in ferrets infected with BL2 H1N1 and the BL3 highly pathogenic avian influenza (HPAI) H5N1 strain (and in H7N9 IAV-infected ferrets if this strain emerges as an epidemic or pandemic strain during the funding period). Our studies will determine whether AZD1236-mediated MMP-9 inhibition has therapeutic efficacy against IAV in both small and large animals sufficient to thereby satisfy the FDA "Two Animal Rule" required to demonstrate efficacy to apply for FDA approval. Successful completion of the work proposed herein may provide a "first in class" therapeutic intervention for serious influenza-mediated lung disease.

Sadis Matalon, Ph.D.

Testing the Efficacy of Hydrogel-based Nanoparticles, Encapsulating Nitrite and Nitric Oxide in the Treatment of Acute Lung Injury and Pulmonary Hypertension (not NIH-funded)

Bromine Inhalation Induced Lung Injury: Novel Mechanisms and Treatment Strategies

World production of Br2 exceeds 300,000 tons per year and accidental spills into the environment during transportation and industrial accidents are common. Br2 inhalation may cause severe injury to the lungs and death from respiratory failure. The purpose of this application is to understand how bromine damages the lungs and find appropriate countermeasures.

Bromine (Br2) is a highly toxic dark-reddish liquid, which evaporates readily to a red vapor with a suffocating odor. World production of Br2 exceeds 300,000 tons per year. Exposure to Br2 causes acute lung injury, death from respiratory failure, and fibrosis. Because of the potential for industrial and transportation accidents to release of large amounts of Br2 in populated areas, Br2 presents a clear and present danger to public health. Few published studies have evaluated the acute and chronic sequelae of Br2 inhalation; treatment remains symptomatic and no effective countermeasures exist. Similar to human pathology, exposure of mice to Br2 causes reactive airway disease syndrome (RADS), increased permeability of the blood gas barrier to plasma proteins, and inflammation followed by sub-epithelial airway fibrosis and significant mortality. The overall purpose of this application is to identify the biochemical and molecular mechanisms responsible for these events and develop appropriate countermeasures. We propose that Br2 and hypobromous acid (HOBr-) interact with and fragment high molecular weight hyaluronan (H-HA), a ubiquitous matrix glycosaminoglycan, to generate highly inflammatory low molecular weight hyaluronan fragments (L-HA). L- HA binds to CD44 and Toll like receptor (TLR)-4, increases intracellular Ca+2 and activates TGF-b1, and RhoA in lung epithelial and airway smooth muscle cells. These events lead to RADS, increased epithelial permeability to plasma proteins, epithelial-mesenchymal cell transition (EMT) of airway cells, sub-epithelial fibrosis, an death from respiratory failure. In addition, we demonstrate for the first time the formation of brominated lipids in the lungs and plasma of mice exposed to Br2. These compounds, formed by the interaction of Br2 with lung plasmalogens, mediate and amplify Br2 lung injury and act as biomarkers of Br2 exposure. Based on solid data we posit that post-Br2 exposure administration of aerosolized YabroÒ (a form of H-HA, currently in clinical trials in Europe for asthma), attenuates lung damage, enhances repair and decreases mortality. Experiments proposed in the first specific aim will assess physiological, biochemical, and morphological changes in mice exposed to Br2 and returned to room air for up to three weeks and test the effectiveness of aerosolized YabroÒ administered post exposure to decrease lung injury and mortality. We will then identify the mechanisms by which Br2 damages rodent and human airway smooth muscle (ASM), bronchial and alveolar type II (ATII) cells. We posit that Br2, brominated lipids, and L-HA increase intracellular Ca2+ and activate RhoA, which lead to increased airway contractility and epithelial permeability. Experiments will: (i) determine membrane potentials by patch clamp; (ii) intracellular Ca+2 by fura-2 fluorescence; (iii) RhoA and ROCK activation; (iv) myosin light chain phosphorylation; and (v) (for epithelial cells) permeability to fluorescent dextrans. Finally, we wll isolate mouse tracheal rings at 1, 24, and 72 hr. post Br2 exposure and measure smooth muscle contraction in response to methacholine.

CIALIS® Reverses Halogen Induced Injury to Pregnant Animals and Their Offspring (Co-PI: Tamas Jilling)

We have discovered that pregnant mice are highly susceptible to bromine. Tadalafil, an FDA approved agent, reverses injury to pregnant mice and offsprings when administered after Br2 exposure. We will investigate the mechanisms involved and identify the optimum way of delivering tadalafil.

The halogen bromine (Br2) is used as water disinfectant, for bleaching fibers, for manufacturing antiepileptic drugs, dyestuffs, flame-retardants, insecticides, drilling fluids, and gasoline additives. When inhaled, it causes exposure-level-dependent acute and chronic pulmonary and systemic injuries ranging from mild eye and airway irritation, to significant damage to cardiopulmonary system and other organs, which can lead to death. Survivors may develop reactive airway disease syndrome, pulmonary fibrosis as well as restrictive and obstructive pulmonary diseases. Presently, there are no studies evaluating acute and chronic sequelae of Br2 inhalation in pregnant rodent and non-rodent models, even though US census bureau data predicts two of every 100 people in the US being pregnant. Exposure of pregnant mice at gestational day 15 (E15) to Br2 (600 ppm for 30 min.) results in 75% mortality over four days, in contrast to 25% mortality in males or non-pregnant females (p<0001). When delivered at E19, fetuses of surviving Br2-exposed mice exhibit severe fetal growth restriction (FGR) and fetal demise (FD). Placentas are poorly developed and express increased levels of short-FMS-like tyrosine kinase-1 (sFlt-1), an anti-angiogenic mediator and biomarker of both preeclampsia and pulmonary hypertension. When born naturally, none of the fetuses survive. Oral administration of an FDA- approved type 5 cyclic nucleotide-specific phosphodiesterase inhibitor (PDE5i; tadalafil) to the dams post- exposure, dramatically improved maternal survival, fetal growth restriction and neonatal survival. We hypothesize that brominated intermediates, formed by the reaction of Br2 and HOBr with plasmalogens cause injury to the endothelium and the placenta, inducing the release of vasoconstrictor and anti-angiogenic mediators which in turn mediate pulmonary vasoconstriction, increased pulmonary artery pressure and right ventricular dysfunction. Tadalafil restores pulmonary and uterine vasodilation, preserves heart function and improves uterine/placental blood supply resulting in maternal and fetal survival. We will test these proposed mechanisms and we will perform the necessary efficacy studies to identify the optimum therapeutic regimen of tadalafil to decrease maternal morbidity and mortality, improve fetal growth restriction and increase fetal survival when administered orally post exposure. Specific Aim #1. To test the hypothesis that exposure of pregnant mice to Br2 at E15 causes extensive pulmonary injury as well as systemic endothelial injury, placental injury, pulmonary hypertension, right heart failure resulting in maternal mortality, fetal growth restriction and fetal demise/stillbirth. Specific Aim #2: To identify the sequence of events and mechanisms involved in the development of maternal vasoconstriction, pulmonary hypertension and right heart failure. Specific Aim #3. To investigate the efficacy of post halogen exposure administration of tadalafil to decrease maternal and fetal death and morbidity and to develop a rabbit (non-rodent) model of Br2 toxicity in pregnancy.

Timothy Ness, M.D., Ph.D.

Effects of Spinal Cord Stimulation on the Bladder Pain Reflex Responses in the Rat (not NIH-funded)

High Frequency Spinal Cord Stimulation on Nociceptive Responses in Rats - Concept Synopsis (not NIH-funded)

Quantitative Studies of Urinary Bladder Sensation

The proposed studies examining acute stress-related effects in rodent model systems will give insight related to the effect of an acute exacerbating factor related to bladder pain. Neural pathways and mechanisms related to an acute stressor - footshock - will be defined. Novel therapeutics related to GABAB-receptor mechanisms will be explored. An improved understanding of sensory processing related to IC and of urinary bladder sensory pathways and their modulation by acute stress and pharmacological manipulations will result in an increased translation of basic science to therapeutics for bladder pain.

Acute and chronic pains originating from the urinary bladder are common clinical entities affecting more than 50% of females at some time in their lives. In an attempt to understand urinary bladder hypersensitivity in a translational manner, this ongoing research project has used rodents to define basic neurophysiological elements of bladder sensation at spinal and supraspinal levels. Using urinary bladder distension (UBD)-evoked reflexes and spinal/supraspinal neuronal responses as experimental endpoints, clinically-relevant models of bladder hypersensitivity have been developed. Whereas the effect of inflammation as an exacerbator of pain has been investigated, the effects of acute stress have not. The present set of studies seeks to reverse the deficit of knowledge that exists in relation to the mechanisms of acute stress as an exacerbator of urinary bladder pain by performing systematic experimental investigations in our translational model. Further, it seeks to explore novel therapeutics in the form of GABAB-receptor based mechanisms. Three Specific Aims are proposed: Specific Aim #1: To quantitatively characterize effects of serotonergic receptor antagonists on reflex and neuronal responses to UBD in rats which experienced neonatal bladder inflammation (NBI) and subsequently received acute footshock (aFS). Specific Aim #2: To quantitatively characterize using immunohistochemical and neurochemical measures, serotonergic agonist and receptor content in the spinal cord of rats which experienced NBI subsequently subjected to aFS. Specific Aim #3: To quantitatively characterize central nervous system effects of GABAB receptor agonists and antagonists on reflex and neuronal responses to UBD in rats which experienced NBI in the presence of exacerbating factors (inflammation, aFS). These studies will expand upon preliminary studies and will determine quantitatively the effects of the classic stressor, intermittent nonpainful footshock, on reflex (visceromotor) and spinal dorsal horn neuronal responses to UBD. Effects of pharmacological manipulations related to pain facilitation will be assessed in animals which experienced neonatal bladder inflammation and controls. The proposed studies examining acute stress-related effects in rodent model systems will give insight related to the effect of an acute exacerbating factor related to bladder pain and will explore novel therapeutics. An improved understanding of sensory processing related to IC and of urinary bladder sensory pathways and their modulation by acute stress will result in an increased translation of basic science to therapeutics for bladder pain.

Mark F. Powell, M.D.

A Randomized Controlled Trial of Regional versus General Anesthesia for Promoting Independence After Hip Fracture (REGAIN Trial)

Brant Wagener, M.D., Ph.D.

Mechanisms of Lung Immunosuppression after Traumatic Brain Injury

Ursula Wesselman, M.D., Ph.D.

Racial Disparities: Pain in Women Treated for Breast Cancer

Due to advances in breast cancer diagnosis and treatment, there has been a dramatic increase in the breast cancer survivor population. Chronic pain during and after breast cancer treatment is a major clinical problem affecting 25 - 60% of breast cancer survivors, and striking racial health disparities in pain and pain-related disability have been well documented with African-American women experiencing a disproportionate burden, however, the mechanisms underlying these disparities remain poorly understood. The goal of this project is to identify pathophysiological mechanisms and psychosocial factors contributing to racial group differences in pain in African- American and non-Hispanic White women treated for breast cancer, and the results of this study should have a major impact on racial pain disparities in the clinical setting by developing methods to identify patients at-risk and to targe those patients for early and tailored interventions.

Due to advances in breast cancer diagnosis and treatment, there has been a dramatic increase in the breast cancer survivor population. Chronic pain is a major clinical problem in this population, affecting 25 - 60% of survivors. Striking racial/ethnic health disparities are well established: African-American breast cancer survivors experience a disproportionate burden of pain compared to non-Hispanic Whites. The long-term goal of this project is to identify and describe racial group differences in the pathophysiological mechanisms and psychosocial factors contributing to pain in breast cancer survivors, and to use this knowledge (a) to determine unique variables which are of greatest importance and utility for determining which patients are at risk for developing persistent pain and (b) to develop mechanism-based effective individualized interventions for pain relief and pain prevention in racially diverse breast cancer survivor populations. We hypothesize that racial group differences in pain and pain-related disability in breast cancer survivors will be mediated by differences in pain processing mechanisms, modulated by autonomic, psychosocial, and inflammatory parameters. To determine the effect of race on pain in women treated for breast cancer we propose a longitudinal prospective study of African-American and non-Hispanic White women diagnosed with stage 1 and stage 2 breast cancer. Aim 1 will assess the prevalence, severity and timing of occurrence of pain in African-American and non- Hispanic White breast cancer survivors. Aim 2 will characterize racial group differences in experimental pain sensitivity and pain modulatory parameters longitudinally in African-American and non-Hispanic White breast cancer survivors using psychophysical measures. Aim 3 will determine the influence of race on the association between autonomic function and pain in African-American and non-Hispanic White breast cancer survivors. Aim 4 will assess the effect of race on the association between psychosocial processes and pain in African- American and non-Hispanic White breast cancer survivors. Aim 5 will assess the relationships between cytokines and pain in African-American and non-Hispanic White women treated for breast cancer. The results of these studies are expected to have a major impact on racial pain disparities in breast cancer survivors: (1) identification of standardized methods to assess racially diverse breast cancer survivors at-risk for chronic pain will allow clinicians and researchers to identify patients at-risk and to target those patients for early and tailored interventions; (2) identification of pathophysiological mechanisms contributing to racial pain disparities will allow to define important new targets for therapy and intervention to reduce and eliminate pain disparities in breast cancer survivors; (3) these studies will provide a key database to design and justify future clinical trials for the prevention and treatment of pain in racially diverse breast cancer survivors; and (4) in a larger context, the results of these studies will not only benefit African-American and non-Hispanic White women with breast cancer, but will have a significant impact on racial pain disparities in all cancer survivors.

Ahmed Zaky, M.D., M.P.H.

A Double-Blind, Randomized, Placebo-Controlled Study of Levosimendan in Patients with Left Ventricular Systolic Dysfunction Undergoing Cardiac Surgery Requiring Cardiopulmonary Bypass