Nitrite Therapy After Cardiac Arrest Reduces Reactive Oxygen Species Generation, Improves Cardiac and Neurological Function, and Enhances Survival via Reversible Inhibition of Mitochondrial Complex I

Three-fourths of cardiac arrest survivors die prior to hospital discharge or suffer significant neurological injury. Excepting therapeutic hypothermia and revascularization, no novel therapies have been developed that improve survival or cardiac and neurological function after resuscitation. Nitrite (NO2−) increases cellular resilience to focal ischemia-reperfusion injury in multiple organs. We hypothesized that nitrite therapy may improve outcomes after the unique global ischemia-reperfusion insult of cardiopulmonary arrest

Imaging of Glucose Metabolism by 13C-MRI Distinguishes Pancreatic Cancer Subtypes in Mice

Metabolic differences among and within tumors can be an important determinant in cancer treatment outcome. However, methods for determining these differences non-invasively in vivo is lacking. Using pancreatic ductal adenocarcinoma as a model, we demonstrate that tumor xenografts with a similar genetic background can be distinguished by their differing rates of the metabolism of 13C labeled glucose tracers, which can be imaged without hyperpolarization by using newly developed techniques for noise suppression. Using this method, cancer subtypes that appeared to have similar metabolic profiles based on steady state metabolic measurement can be distinguished from each other. The metabolic maps from 13C-glucose imaging localized lactate production and overall glucose metabolism to different regions of some tumors. Such tumor heterogeneity would not be not detectable in FDG-PET

Multimodal Atlas of the Murine Inner Ear: From Embryo to Adult

The inner ear is a complex organ housed within the petrous bone of the skull. Its intimate relationship with the brain enables the transmission of auditory and vestibular signals via cranial nerves. Development of this structure from neural crest begins in utero and continues into early adulthood. However, the anatomy of the murine inner ear has only been well-characterized from early embryogenesis to post-natal day 6. Inner ear and skull base development continue into the post-natal period in mice and early adulthood in humans. Traditional methods used to evaluate the inner ear in animal models, such as histologic sectioning or paint-fill and corrosion, cannot visualize this complex anatomy in situ. Further, as the petrous bone ossifies in the postnatal period, these traditional techniques become increasingly difficult. Advances in modern imaging, including high resolution Micro-CT and MRI, now allow for 3D visualization of the in situ anatomy of organs such as the inner ear. Here, we present a longitudinal atlas of the murine inner ear using high resolution ex vivo Micro-CT and MRI

Dynamic Imaging of Glucose and Lactate Metabolism by C-13-MRS without Hyperpolarization

Abstract Metabolic reprogramming is one of the defining features of cancer and abnormal metabolism is associated with many other pathologies. Molecular imaging techniques capable of detecting such changes have become essential for cancer diagnosis, treatment planning, and surveillance. In particular, 18F-FDG (fluorodeoxyglucose) PET has emerged as an essential imaging modality for cancer because of its unique ability to detect a disturbed molecular pathway through measurements of glucose uptake. However, FDG-PET has limitations that restrict its usefulness in certain situations and the information gained is limited to glucose uptake only.13C magnetic resonance spectroscopy theoretically has certain advantages over FDG-PET, but its inherent low sensitivity has restricted its use mostly to single voxel measurements unless dissolution dynamic nuclear polarization (dDNP) is used to increase the signal, which brings additional complications for clinical use. We show here a new method of imaging glucose metabolism in vivo by MRI chemical shift imaging (CSI) experiments that relies on a simple, but robust and efficient, post-processing procedure by the higher dimensional analog of singular value decomposition, tensor decomposition. Using this procedure, we achieve an order of magnitude increase in signal to noise in both dDNP and non-hyperpolarized non-localized experiments without sacrificing accuracy. In CSI experiments an approximately 30-fold increase was observed, enough that the glucose to lactate conversion indicative of the Warburg effect can be imaged without hyper-polarization with a time resolution of 12s and an overall spatial resolution that compares favorably to 18F-FDG PET

Regulation of Motor Function and Behavior by Atypical Chemokine Receptor 1

The final publication is available at Springer via http://dx.doi.org/10.1007/s10519-014-9665-7Atypical Chemokine Receptor 1 (ACKR1), previously known as the Duffy Antigen Receptor for Chemokines, stands out among chemokine receptors for its high selective expression on Purkinje cells of the cerebellum, consistent with the ability of ACKR1 ligands to activate Purkinje cells in vitro. Nevertheless, evidence for ACKR1 regulation of brain function in vivo has been lacking. Here we demonstrate that Ackr1−/− mice have markedly impaired balance and ataxia when placed on a rotating rod and increased tremor when injected with harmaline, a drug that induces whole-body tremor by activating Purkinje cells. Ackr1−/− mice also exhibited impaired exploratory behavior, increased anxiety-like behavior and frequent episodes of marked hypoactivity under low-stress conditions. The behavioral phenotype of Ackr1−/− mice was the opposite of the phenotype occurring in mice with cerebellar degeneration and the defects persisted when Ackr1 was deficient only on non-hematopoietic cells. We conclude that normal motor function and behavior depend in part on negative regulation of Purkinje cell activity by Ackr1

Metabolic and physiologic imaging biomarkers of the tumor microenvironment predict treatment outcome with radiation or a hypoxia-activated prodrug in mice.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by hypoxic niches that lead to treatment resistance. Therefore, studies of tumor oxygenation and metabolic profiling should contribute to improved treatment strategies. Here we define two imaging biomarkers that predict differences in tumor response to therapy: 1) partial oxygen pressure (pO2), measured by EPR imaging; and 2) [1- 13C] pyruvate metabolism rate, measured by hyperpolarized 13C MRI. Three human PDAC xenografts with varying treatment sensitivity (Hs766t, MiaPaCa-2, and Su.86.86) were grown in mice. The median pO2 of the mature Hs766t, MiaPaCa-2, and Su.86.86 tumors was 9.1±1.7, 11.1±2.2, and 17.6±2.6 mmHg, and the rate of pyruvate-to-lactate conversion was 2.72±0.48, 2.28±0.26, and 1.98±0.51 min-1 , respectively (n=6, each). These results are in agreement with steady state data of matabolites quantified by mass spectroscopy and histological analysis indicating glycolytic and hypoxia profile in Hs766t, MiaPaca-2, and Su.86.86 tumors. Fractionated radiation therapy (5 Gy x 5) resulted in a tumor growth delay of 16.7±1.6 and 18.0±2.7 days in MiaPaca-2 and Su.86.86 tumors, respectively, compared to 6.3±2.7 days in hypoxic Hs766t tumors. Treatment with gemcitabine, a first-line chemotherapeutic agent, or the hypoxia-activated prodrug TH-302 was more effective against Hs766t tumors (20.0±3.5 and 25.0±7.7 days increase in survival time, respectively) than MiaPaCa-2 (2.7±0.4 and 6.7±0.7 days) and Su.86.86 (4.7±0.6 and 0.7±0.6 days) tumors. Collectively, these results demonstrate the ability of molecular imaging biomarkers to predict the response of PDAC to treatment with radiation therapy and TH-30

Urea Amidolyase (\u3ci\u3eDUR1,2\u3c/i\u3e) Contributes to Virulence and Kidney Pathogenesis of Candida albicans

The intracellular enzyme urea amidolyase (Dur1,2p) enables C. albicans to utilize urea as a sole nitrogen source. Because deletion of the DUR1,2 gene reduces survival of C. albicans co-cultured with a murine macrophage cell line, we investigated the role of Dur1,2p in pathogenesis using a mouse model of disseminated candidiasis. A dur1,2Δ/dur1,2Δ strain was significantly less virulent than the wild-type strain, showing significantly higher survival rate, better renal function, and decreased and less sustained fungal colonization in kidney and brain. Complementation of the mutant restored virulence. DUR1,2 deletion resulted in a milder host inflammatory reaction. Immunohistochemistry, flow cytometry, and magnetic resonance imaging showed decreased phagocytic infiltration into infected kidneys. Systemic cytokine levels of wild-type mice infected with the dur1,2 mutant showed a more balanced systemic pro-inflammatory cytokine response. Host gene expression and protein analysis in infected kidneys revealed parallel changes in the local immune response. Significant differences were observed in the kidney IL-1 inflammatory pathway, IL-15 signaling, MAP kinase signaling, and the alternative complement pathway. We conclude that Dur1,2p is important for kidney colonization during disseminated candidiasis and contributes to an unbalanced host inflammatory response and subsequent renal failure. Therefore, this Candida-specific enzyme may represent a useful drug target to protect the host from kidney damage associated with disseminated candidiasis

Metabolic and physiologic imaging biomarkers of the tumor microenvironment predict treatment outcome with radiation or a hypoxia-activated prodrug in mice

Pancreatic ductal adenocarcinoma (PDAC) is characterized by hypoxic niches that lead to treatment resistance. Therefore, studies of tumor oxygenation and metabolic profiling should contribute to improved treatment strategies. Here we define two imaging biomarkers that predict differences in tumor response to therapy: 1) partial oxygen pressure (pO2), measured by EPR imaging; and 2) [1-13C] pyruvate metabolism rate, measured by hyperpolarized 13C MRI. Three human PDAC xenografts with varying treatment sensitivity (Hs766t, MiaPaCa-2, and Su.86.86) were grown in mice. The median pO2 of the mature Hs766t, MiaPaCa-2, and Su.86.86 tumors was 9.1±1.7, 11.1±2.2, and 17.6±2.6 mmHg, and the rate of pyruvate-to-lactate conversion was 2.72+/-0.48, 2.28+/-0.26, and 1.98+/-0.51 min-1, respectively (n=6, each). These results are in agreement with steady state data of matabolites quantified by mass spectroscopy and histological analysis indicating glycolytic and hypoxia profile in Hs766t, MiaPaca-2, and Su.86.86 tumors. Fractionated radiation therapy (3 Gy x 5) resulted in a tumor growth delay of 16.7±1.6 and 18.0±2.7 days in MiaPaca-2 and Su.86.86 tumors, respectively, compared to 6.3±2.7 days in hypoxic Hs766t tumors. Treatment with gemcitabine, a first-line chemotherapeutic agent, or the hypoxia-activated prodrug TH-302 was more effective against Hs766t tumors (20.0+/-3.5 and 25.0+/-7.7 days increase in survival time, respectively) than MiaPaCa-2 (2.7±0.4 and 6.7±0.7 days) and Su.86.86 (4.7±0.6 and 0.7±0.6 days) tumors. Collectively, these results demonstrate the ability of molecular imaging biomarkers to predict the response of PDAC to treatment with radiation therapy and TH-302