Active Research Projects
(updated Spring 2016)
Aftab Ahmad, Ph.D., Associate Professor
The primary goal of my research is to understand molecular mechanisms by which hypoxic factors regulate vascular growth and proliferation in the lung and also how these factors or their loss can contribute to disease pathogenesis. Towards understanding hypoxic factors regulating vascular growth we have focused our attention on HIF-2a, which is expressed predominantly in the vasculature and is perceived as being important in vascular growth. However, mechanisms by which it can promote vascular growth independent of HIF-1a(a transcription factor with DNA binding site identical to HIF-2a) are still not clear. We have recently identified functional differences between HIF-1aand HIF-2ain vascular endothelial and smooth muscle cells of the pulmonary vasculature. We have shown that HIF-2apromotes proliferation and an angiogenic phenotype in pulmonary endothelial cells whereas HIF-1a had minimal effects. Additionally, we found that HIF-1apromotes a proliferative phenotype in pulmonary vascular smooth muscle cells. We have also identified adenosine A2A receptor as a unique downstream target of HIF-2ain human pulmonary endothelial cells. Studies are underway to identify additional targets of HIF-2athat could be important during development and various diseases.
In a study currently being carried out we are exploring the role of hypoxia-inducible transcription factors and adenosine A2A receptor in pulmonary hypertension. We have found that A2A receptor expression increases in vascular lesions of patients with pulmonary hypertension. We have extended these studies to a well- established rat model of pulmonary hypertension and are using gene knockdown approaches to address this question.
My other area of interest is in understanding the role of extracellular RNA (exRNA) in lung injury induced by inhalation of toxic chemicals like chlorine and CEES/sulfur mustard. RNA released from cells as a result of injury or through the normal apoptotic process can also activate signaling pathways. It is a unique molecule that can accelerate the inflammatory pathway and also activate the coagulation cascade. We are currently assessing its role in such chemical-induced toxicities and its potential as a therapeutic target.
Key words: Vasculature, endothelium, hypoxia, remodeling, hypoxia-inducible transcription factors, adenosine.
Judy Creighton, Ph.D.
Our research focuses on the discovery of endogenous repair mechanisms situated in the lung’s vascular lining, the endothelium. Although this thin layer of cells lines all vascular beds, not all endothelial cells are the same. Endothelium from various organs, and even from different vascular beds within the same organ, are physically and functionally distinct. We aim to understand how endothelium lining specific vascular segments within the lung contributes to overall lung health and to vascular repair following injury or disease. We find that the enzyme Adenosine Monophosphate Kinase (AMPK), classically described as a metabolic sensor, functions as an injury response mechanism in the lung’s capillary bed. Interestingly, our data show that AMPK promotes calcium signaling necessary for endothelial barrier repair. Calcium signaling is often associated with disruption of the endothelial lining. However, our work shows that AMPK activates a discrete calcium mechanism, which reorganizes the cytoskeleton crucial for cadherin adherens’ junction assembly and endothelial cell-cell adhesion. Specifically, our research tests the hypothesis that AMPKα1 and N-cadherin function in tandem as a rapid response mechanism allowing the lung’s capillary endothelium to re-establish tight cell-cell adhesions quickly and limit increased permeability. Our work supports the idea of endothelial biomedicine with the goal of developing therapeutic strategies targeted toward segment specific vascular disease.
Current Projects
- Function of AMPK relative to sub-cellular localization and tissue specific expression.
- Metabolic mechanisms controlling endothelial permeability.
- Endothelial cell-cell adhesion: cadherin expression and adherens junction composition.
- Calcium channel regulation by vascular protective mechanisms in pulmonary endothelium.
- Endothelial phenotype specific response to stimuli.
Jennifer DeBerry, Ph.D., Assistant Professor
Prior/ongoing studies relate to characterization of afferents innervating the urinary bladder, descending modulation of bladder nociceptive transmission, and mechanisms and mediators of visceral hypersensitivity, including the roles of TRP channels and growth factors in afferent sensitization. Specific project opportunities currently include the following:
Effects of amygdala central nucleus (CeA) glucocorticoids versus mineralocorticoids on bladder sensation in the rat. These studies involve stereotaxic application of drugs and antagonists to the CeA and subsequent behavioral testing to assess changes in bladder sensation.
Effect of unilateral CeA lesions on stress-induced bladder hyperalgesia in the rat. Bilateral, electrolytic CeA lesions prevent acute stress-induced bladder hyperalgesia. Evidence suggests that this effect may be lateralized. These studies involve stereotaxic surgery to selectively lesion left versus right CeA prior to acute stress (footshock) exposure and subsequent behavioral testing to assess changes in bladder sensation.
Contributions of bladder afferent subpopulations to pain and organ dysfunction in the mouse. These studies involve optical stimulation of specific, channelrhodopsin-expressing, bladder afferent subtypes to determine their contributions to behavioral indices of bladder pain versus function (micturition).
Burel Goodin, Ph.D., Assistant Professor (Department of Psychology)
Secondary Appointment: Anesthesiology
Dr. Goodin is a clinical health psychologist with specialization in pain related behavioral medicine, examining the interactions of psychosocial and biobehavioral characteristics in relations to the experience of pain through the key pathways of stress-related hormones (neuroendocrine functions) and immune function. Dr. Goodin has been involved with several different studies that afforded him the opportunity to become very familiar with experimental models of evokes pain using quantitative sensory testing. As part of these studies, he has developed and refined methods to assess pain sensitivity and modulation (e.g., endogenous pain inhibition and facilitation) using dynamic experimental pain stimuli. The next step is to begin evaluating the impact of factors such as sleep disturbance and neuropeptides (e.g. oxytocin) on pain sensitivity and modulation across the adult lifespan.
Jianguo Gu, Ph.D., Professor
Research in Dr. Gu’s lab has been to study sensory transduction, encoding and transmission in the somatosensory system, to investigate cellular and molecular mechanisms underlying inflammatory and neuropathic pain, and to explore new therapeutic targets for effectively treating pathological pain conditions in patients. A current focus of his lab is on transient receptor potential M8 channels (TRPM8) and low-threshold voltage-gated K+ channels. Dr. Gu’s lab is studying the roles of these channels in encoding cold stimuli at primary afferent nerve endings and in mediating physiological and pathological pain induced by cold temperatures. The long-term goal of this research project is to develop therapeutic compounds targeting these channels for clinical treatment of cold pain in patients. Another current research focus of Dr. Gu’s lab is on the cellular and molecular mechanisms underlying the transduction and encoding of mechanical stimulation such as gentle touch. The long-term goal of this project is to identify therapeutic targets for treating sensory disorders such as mechanical allodynia (pain induced by gentle touch).
Mechanism of Nociception Induced by Innocuous Cold in Trigeminal System
Trigeminal neuropathic pain is the most common debilitating pain disorder and is known to respond poorly to treatment including opioids in human patients. One common problem of trigeminal neuropathic pain is orofacial cold allodynia and hyperalgesia, an exaggerated painful condition induced by innocuous cold or mild noxious cold temperatures. There is a pressing need to better understand the mechanisms of trigeminal neuropathic pain and identify effective therapeutic targets. Our long-term goal is to identify the cellular and molecular mechanisms underlying trigeminal neuropathic pain that manifests orofacial cold allodynia and hyperalgesia with the hope of finding effective therapeutic targets.
Cellular and ion channel mechanisms underlying the sense of light touch in mammals
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 the Merkel cell-neurite complex, a sensory structure essential for sensing light touch in mammals.
Kevin Harrod, Ph.D., Professor
Respiratory infections constitute the most common cause of human malady globally. Despite extraordinary advances in diagnostics, few therapeutic approaches are available for treating common respiratory viral infections. My interests are grounded in using emerging technologies to elucidate molecular targets for therapeutic intervention against respiratory viruses, including influenza, RSV, and emerging coronaviruses. Furthermore, we seek to understand the aerobiology of viral transmission as well as the response of the host microbiome to infection and carriage.
Ming Yuan Jian, M.D., Ph.D., Instructor
Endothelial repair following vascular injury involves cell proliferation and migration. Endostatin maintains a functional vascular barrier by regulating cellular proliferation and migration. However, elevated levels of endostatin inhibit these critical processes and correlate positively with severity of inflammation-induced lung damage. Neither the source of endostatin, nor its role in progression of vascular disease is known. We reasoned endostatin released by lung endothelium in response to inflammatory mediators slows pulmonary vascular repair by limiting the endothelial response to injury. Expression of endostatin was reduced in pulmonary microvascular endothelial cells (PMVECs) using a shRNA-mediated lentiviral approach. Cell monolayer permeability, resistance, cell proliferation, and migration were compared between wild-type and endostatin knockdown cells. Western blot data showed that LPS increased endostatin expression in wild-type PMVECs in a dose dependent manner. LPS decreased PMVEC proliferation and lowered cell monolayer resistance, effects which were exacerbated by exogenous application of endostatin. The effects of LPS were diminished in PMVECs expressing shRNA to endostatin. The LPS-induced increase in PMVEC monolayer permeability was reduced in endostatin knockdown cells. Moreover, LPS inhibited gap resealing time in a scratch wound assay that was further decreased in the presence of endostatin. Conclusion: endostatin limits lung endothelial repair in inflammation.
Sadis Matalon, Ph.D., Dr.Sc. (Hon.), Distinguished Professor, Alice McNeal Endowed Chair of Anesthesiology, Vice Chair, Research
Viral induced injury to the mammalian alveolar epithelium.
Influenza (flu) is a contagious respiratory illness caused by flu viruses, leading to about 36,000 deaths every year in the United States alone, with the potential for at least a tenfold increase in epidemic and pandemic scenarios. Respiratory Syncytial Virus (RSV) is a member of the pneumovirus genus of the paramyxoviridae, and has a negative-sense, non-segmented, single-stranded RNA genome. It is the most common cause of lower respiratory tract disease in infants and children worldwide, is a frequent initiator of acute asthma exacerbations in young children, and has a disease impact comparable to that of non-pandemic influenza A in the elderly. We are currently using a variety of biophysical, molecular biology and physiological techniques to assess the basic mechanisms by which viral proteins and active replicating viruses interact with and modulate key functions of the alveolar epithelium both in vitro and in vivo. Results of these studies help us formulate new strategies for decreasing rhinnorhea and pulmonary edema, common consequences of viral infections. Publications: Influenza virus M2 protein inhibits epithelial sodium channels by increasing reactive oxygen species. FASEB J. 2009 Nov;23(11):3829-42. Epub 2009 Jul 13.PMID: 19596899. Respiratory syncytial virus inhibits lung epithelial Na+ channels by up-regulating inducible nitric-oxide synthase. J Biol Chem. 2009 Mar 13;284(11):7294-306. Epub 2009 Jan 8.
Developing countermeasures against oxidant gases.
Chlorine (Cl2) is a highly irritant and reactive gas produced in large quantities throughout the world. Exposure to Cl2 released into the atmosphere during transportation and industrial accidents as well as during acts of terrorism, has resulted in significant morbidity and mortality to both humans and animals. Physiological and biophysical and biochemical studies utilizing in vitro systems and animals exposed to chlorine gas have helped us elucidate the biochemical mechanisms responsible for chlorine injury to pulmonary and extrapulmonary targets Publications: Elucidating mechanisms of chlorine toxicity: reaction kinetics, thermodynamics, and physiological implications. Am J Physiol Lung Cell Mol Physiol. 2010; 299(3):L289-300. Epub 2010 Jun 4. Review.PMID: 20525917; Inhibition of lung fluid clearance and epithelial Na+ channels by chlorine, hypochlorous acid and chloramines. J Biol Chem. 2010 Mar 26;285(13):9716-28. PMID: 20106988; Mechanisms and modification of chlorine-induced lung injury in animals. Proc Am Thorac Soc. 2010 Jul;7(4):278-83. Review.PMID: 20601632; Chlorine Gas Exposure Causes Systemic Endothelial Dysfunction by Inhibiting eNOS-dependent Signaling. Am J Respir Cell Mol Biol. 2010 Dec 3. [Epub ahead of print]PMID: 21131444; Post Exposure Administration of a {beta}2-Agonist Decreases Chlorine Induced Airway Hyper-Reactivity in Mice. Am J Respir Cell Mol Biol. 2010 Sep 20. [Epub ahead of print]; PMID:20855648. Based on these studies we have formulated effective approaches to counteract this injury. Post exposure administration of antioxidants, nitrite or β2 agonists decreased pulmonary injury and improved survival in rodents exposed to Cl2 gas by a variety of mechanisms. Publications Ascorbate and Deferoxamine Administration Post Chlorine Exposure Decrease Mortality and Lung Injury in Mice. Am J Respir Cell Mol Biol. 2010 Dec 3. [Epub ahead of print]PMID: 21131440; PMID:21148791
Mali Mathru, M.D., Professor
The effect of remote ischemic preconditioning on the graft on patients undergoing live donor kidney transplant
Remote ischemic preconditioning (RIPC), a phenotype of ischemic preconditioning, has been found to provide protection from I/R in humans. Several proof of concept clinical trials have shown that transient ischemia reperfusion of lower extremities confers protection to kidneys in patients undergoing endovascular or open surgical repair of an abdominal aortic aneurysm and in patients undergoing cardiac surgery. Furthermore, a randomized pilot clinical trial demonstrated that application of RIPC in high risk patients with kidney dysfunction undergoing coronary angioplasty reduced the incidence of procedure related contrast media induced AKI. To date the efficacy of RIPC in protecting renal allografts from I/R injury during renal transplantation has not been systematically investigated. In this current proof of concept proposal we will test the central hypothesis that application of RIPC in donors and recipients during live donor kidney transplantation will reduce the severity of graft injury and improve outcome. We propose the following specific aim: To examine the effect of RIPC on clinical and biochemical markers of graft function in patients undergoing live donor kidney transplantation.
In this study, patients undergoing live donor kidney transplantation will be allocated to the control group or RIPC group. Before allograft implantation, RIPC will be accomplished both in the donor and the recipient by inducing intermittent extremity ischemia through four five cycles of oscillometric blood pressure cuff inflation. The monitored clinical end points will include total urine output following kidney reperfusion over three days, plasma creatinine declination over five days, initiation of dialysis, and development of graft injury. Magnitude of graft injury will be measured using biochemical markers, such as, plasma and urinary concentration of neutrophil gelatinase associated lipocalin (NGAL), IL-18, and KIM-1. By rejecting our null hypothesis, RIPC may serve as a safe, cost-effective protective strategy to prevent allograft injury in the clinical setting of live donor kidney transplantation.
RBC Transfusion may exacerbate cerebral vasopasm associated with subarachnoid hemorrhage
Red blood transfusion is a commonly employed therapy in the management of patients with subarachnoid hemorrhage (SAH). Emerging evidence suggest that patients with SAH who receive packed red blood cell transfusion (PRBC) are at greater risk for vasospasm and poor outcome. The mechanistic link between PRBC transfusion and vasospasm has not been fully uncovered but it has been suggested that transfusion of stored PRBC’s is associated with nitric oxide (NO) dysregulation, characterized by an imbalance between red cell/free hemoglobin ( fHgb ) and ensuing inhibition of NO signaling. If this concept were to be true, transfusion of RBC with a greater NO-inhibitory capacity may blunt the cerebral vessels vasodilatory response and exacerbate vasospasm. Patients with SAH with preexistent endothelial dysfunction are particularly vulnerable to this adverse effect of transfusion. This current proposal will examine the general hypothesis that decreased bioavailability of NO after PRBC transfusion due to time –and storage condition- dependent changes in NO scavenging by RBCs, leads to increase in vasospasm with reduction in regional blood flow.
Considering these facts, a PRBC transfusion could potentially worsen cerebral vasospasm measured by Trans-Cranial Doppler (TCD). TCD uses a graded system for detecting vasospasm called Lindegaard ratios. If it can be shown that the free Hgb in transfused RBCs scavenges NO and also causes worsening of vasospasm, this study may be useful in reducing RBC transfusion to SAH patients allowing for conservation of blood products and other ill effects associated with blood transfusions. To establish a mechanistic link between PRBC transfusion and decreased bioavailability of NO and exacerbation of vasospasm we will measure hematocrit, ages of each unit of RBC and measure plasma free hemoglobin, haptoglobin, heme, hemopexin and nitrite/nitrate to correlate the generation of free radicals. We will be doing the study on 128 patients with interim analysis once we have 20 patients recruited.
David Miller, M.D., Assistant Professor
We are looking at the incidence of deep venous thrombosis and pulmonary embolism rates in the NICU prior to and after the changes in the vendor supplying us with sequential compression devices. I am also looking at devising a new DVT/PTE prophylaxis protocol and will need to track the outcomes prior to and after initiation of the protocol.
Next, I have been asked to write a review article for a journal entitled “Medical Research Archives.” This review will likely be on the effects of anemia in subarachnoid hemorrhage.
We will also need gel gathering data for the "RBC transfusion in subarachnoid hemorrhage” project. This project is still in its infancy.
Timothy Ness, M.D., Ph.D., Simon Gelman Endowed Professor and Associate Vice Chair for Clinical Research, Director, Clinician Academic Achievement Program
Meredith Robbins, Ph.D., Associate Professor
Exacerbation of pain by stress/anxiety is a frequent clinical observation associated with multiple painful diseases, including urologic chronic pelvic pain syndrome (UCPPS). UCPPS, traditionally referred to as interstitial cystitis / painful bladder syndrome (IC/PBS) and chronic prostatitis, is a chronic painful urological condition with no known etiology and no cure. Urological pain in UCPPS patients is markedly exaggerated because of stress/anxiety, and these patients also have a high prevalent of multiple co-morbid conditions, including rheumatological – musculoskeletal disorders, which make the determination of treatment options of individuals challenging since pharmacological interventions that may relieve pain associated with one condition may worsen a co-exiting condition. Drugs that act on serotonergic systems (i.e. agonists, antagonists, reuptake inhibitors) have been used with varied success and also play a key role in the treatment of anxiety disorders.
Lee Ann Riesenberg, R.N., Ph.D., C.M.Q., Associate Director Education, Professor
Systematic Reviews of the Literature: I have several systematic reviews of the literature on various medical, medical education, and quality and patient safety topics. There is an existing team of research assistants, residents and faculty working on these systematic reviews.
Handoff and Transitions of Care:
· Implementation of Feedback and Evaluation of resident patient handoffs skills. Patient handoff and transitions of care require learners to acquire a complex set of communication, teamwork, prioritization, and organizational skills. This study is aimed at assessing ideal perioperative handoff feedback and evaluation.
· CVICU Nurse Practitioner Handoffs intervention. This study involves observation of Nurse Practitioner handoffs in the CVICU
Jean-Francois Pittet, M.D. David Hill Chestnut Endowed Professor of Anesthesiology, Vice Chair and Director,Division of Critical Care and Perioperative Medicine
The objective of this study is to examine the correlation between the severity of nosocomial pneumonia and the presence of the P. aeruginosa T3SS toxin ExoY in bacterial cultures obtained from mini-BALs of ICU patients in a prospective, observational study.