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Xiao Y, Chen Y, Huang S, He H, Hu N, Lin S, You Z. The reduction of microglial efferocytosis is concomitant with depressive-like behavior in CUMS-treated mice. J Affect Disord 2024; 352:76-86. [PMID: 38360363 DOI: 10.1016/j.jad.2024.02.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 02/07/2024] [Accepted: 02/12/2024] [Indexed: 02/17/2024]
Abstract
BACKGROUND Microglial efferocytosis plays a crucial role in facilitating and sustaining homeostasis in the central nervous system, and it is involved in neuropsychiatric disorders. How microglial efferocytosis is affected under the condition of major depressive disorder (MDD) remains elusive. In this study, we hypothesized that microglial efferocytosis in the hippocampus is impaired in the chronic unpredicted mild stress (CUMS) model of MDD, which is involved in the development of MDD. METHOD Depressive-like behavior in adult male mice was induced by CUMS and confirmed by behavioral tests. Microglial efferocytosis was evaluated using immunofluorescence staining of hippocampal slices and primary microglia co-cultured with apoptotic cells. The protein and mRNA levels of phagocytosis-related molecules and inflammation-related cytokines were detected using western blotting and RT-qPCR, respectively. Annexin V was injected to mimic impairment of microglial efferocytosis. TREM2-siRNA was further used on primary microglia to examine efferocytosis-related signaling pathways. RESULTS Microglia were activated and the expression of proinflammatory cytokines was increased in CUMS mice, while microglial efferocytosis and efferocytosis-related molecules were decreased. Inhibition of the TREM2/Rac1 pathway impaired microglial efferocytosis. Annexin V injection inhibited microglial efferocytosis, increased inflammation in the hippocampus and depressive-like behavior. LIMITATIONS The potential antidepressant effect of the upregulation of the TREM2/Rac1 pathway was not evaluated. CONCLUSIONS Impairment of microglial efferocytosis is involved in the development of depressive-like behavior, with downregulation of the TREM2/Rac1 pathway and increased inflammation. These results may increase our understanding of the pathophysiological mechanisms associated with MDD and provide novel targets for therapeutic interventions.
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Affiliation(s)
- Ying Xiao
- Laboratory of Aging Research, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China; Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China.
| | - Yuxiang Chen
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Shiqi Huang
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Hui He
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Nan Hu
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Shanyu Lin
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Zili You
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 611731, China.
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Tools and Biomarkers for the Study of Retinal Ganglion Cell Degeneration. Int J Mol Sci 2022; 23:ijms23084287. [PMID: 35457104 PMCID: PMC9025234 DOI: 10.3390/ijms23084287] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/03/2022] [Accepted: 04/08/2022] [Indexed: 11/17/2022] Open
Abstract
The retina is part of the central nervous system, its analysis may provide an idea of the health and functionality, not only of the retina, but also of the entire central nervous system, as has been shown in Alzheimer’s or Parkinson’s diseases. Within the retina, the ganglion cells (RGC) are the neurons in charge of processing and sending light information to higher brain centers. Diverse insults and pathological states cause degeneration of RGC, leading to irreversible blindness or impaired vision. RGCs are the measurable endpoints in current research into experimental therapies and diagnosis in multiple ocular pathologies, like glaucoma. RGC subtype classifications are based on morphological, functional, genetical, and immunohistochemical aspects. Although great efforts are being made, there is still no classification accepted by consensus. Moreover, it has been observed that each RGC subtype has a different susceptibility to injury. Characterizing these subtypes together with cell death pathway identification will help to understand the degenerative process in the different injury and pathological models, and therefore prevent it. Here we review the known RGC subtypes, as well as the diagnostic techniques, probes, and biomarkers for programmed and unprogrammed cell death in RGC.
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The Role of (99m)Tc-Annexin V Apoptosis Scintigraphy in Visualizing Early Stage Glucocorticoid-Induced Femoral Head Osteonecrosis in the Rabbit. BIOMED RESEARCH INTERNATIONAL 2016; 2016:7067259. [PMID: 26989689 PMCID: PMC4771895 DOI: 10.1155/2016/7067259] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 01/17/2016] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To validate the ability of (99m)Tc-Annexin V to visualize early stage of glucocorticoid-induced femoral head necrosis by comparing with (99m)Tc-MDP bone scanning. METHODS Femoral head necrosis was induced in adult New Zealand white rabbits by intramuscular injection of methylprednisolone. (99m)Tc-Annexin scintigraphy and (99m)Tc-MDP scans were performed before and 5, 6, and 8 weeks after methylprednisolone administration. Rabbits were sacrificed at various time points and conducted for TUNEL and H&E staining. RESULTS All methylprednisolone treated animals developed femoral head necrosis; at 8 weeks postinjection, destruction of bone structure was evident in H&E staining, and apoptosis was confirmed by the TUNEL assay. This was matched by (99m)Tc-Annexin V images, which showed a significant increase in signal over baseline. Serial (99m)Tc-Annexin V scans revealed that increased (99m)Tc-Annexin V uptake could be observed in 5 weeks. In contrast, there was no effect on (99m)Tc-MDP signal until 8 weeks. The TUNEL assay revealed that bone cell apoptosis occurred at 5 weeks. CONCLUSION (99m)Tc-Annexin V is superior to (99m)Tc-MDP for the early detection of glucocorticoid-induced femoral head necrosis in the rabbit and may be a better strategy for the early detection of glucocorticoid-induced femoral head necrosis in patients.
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Advances in retinal ganglion cell imaging. Eye (Lond) 2015; 29:1260-9. [PMID: 26293138 DOI: 10.1038/eye.2015.154] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 06/29/2015] [Indexed: 12/18/2022] Open
Abstract
Glaucoma is one of the leading causes of blindness worldwide and will affect 79.6 million people worldwide by 2020. It is caused by the progressive loss of retinal ganglion cells (RGCs), predominantly via apoptosis, within the retinal nerve fibre layer and the corresponding loss of axons of the optic nerve head. One of its most devastating features is its late diagnosis and the resulting irreversible visual loss that is often predictable. Current diagnostic tools require significant RGC or functional visual field loss before the threshold for detection of glaucoma may be reached. To propel the efficacy of therapeutics in glaucoma, an earlier diagnostic tool is required. Recent advances in retinal imaging, including optical coherence tomography, confocal scanning laser ophthalmoscopy, and adaptive optics, have propelled both glaucoma research and clinical diagnostics and therapeutics. However, an ideal imaging technique to diagnose and monitor glaucoma would image RGCs non-invasively with high specificity and sensitivity in vivo. It may confirm the presence of healthy RGCs, such as in transgenic models or retrograde labelling, or detect subtle changes in the number of unhealthy or apoptotic RGCs, such as detection of apoptosing retinal cells (DARC). Although many of these advances have not yet been introduced to the clinical arena, their successes in animal studies are enthralling. This review will illustrate the challenges of imaging RGCs, the main retinal imaging modalities, the in vivo techniques to augment these as specific RGC-imaging tools and their potential for translation to the glaucoma clinic.
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Eggleston H, Panizzi P. Molecular imaging of bacterial infections in vivo: the discrimination of infection from inflammation. INFORMATICS (MDPI) 2014; 1:72-99. [PMID: 26985401 PMCID: PMC4790455 DOI: 10.3390/informatics1010072] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Molecular imaging by definition is the visualization of molecular and cellular processes within a given system. The modalities and reagents described here represent a diverse array spanning both pre-clinical and clinical applications. Innovations in probe design and technologies would greatly benefit therapeutic outcomes by enhancing diagnostic accuracy and assessment of acute therapy. Opportunistic pathogens continue to pose a worldwide threat, despite advancements in treatment strategies, which highlights the continued need for improved diagnostics. In this review, we present a summary of the current clinical protocol for the imaging of a suspected infection, methods currently in development to optimize this imaging process, and finally, insight into endocarditis as a model of infectious disease in immediate need of improved diagnostic methods.
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Affiliation(s)
- Heather Eggleston
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849
| | - Peter Panizzi
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849
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Zhang X, Paule MG, Wang C, Slikker W. Application of microPET imaging approaches in the study of pediatric anesthetic-induced neuronal toxicity. J Appl Toxicol 2013; 33:861-8. [DOI: 10.1002/jat.2857] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 12/13/2012] [Accepted: 12/14/2012] [Indexed: 12/14/2022]
Affiliation(s)
- Xuan Zhang
- Division of Neurotoxicology; National Center for Toxicological Research (NCTR)/FDA; Jefferson; AR; USA
| | - Merle G. Paule
- Division of Neurotoxicology; National Center for Toxicological Research (NCTR)/FDA; Jefferson; AR; USA
| | - Cheng Wang
- Division of Neurotoxicology; National Center for Toxicological Research (NCTR)/FDA; Jefferson; AR; USA
| | - William Slikker
- Office of the Director; National Center for Toxicological Research (NCTR)/FDA; Jefferson; AR; USA
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Chhunchha B, Fatma N, Kubo E, Rai P, Singh SP, Singh DP. Curcumin abates hypoxia-induced oxidative stress based-ER stress-mediated cell death in mouse hippocampal cells (HT22) by controlling Prdx6 and NF-κB regulation. Am J Physiol Cell Physiol 2013; 304:C636-55. [PMID: 23364261 DOI: 10.1152/ajpcell.00345.2012] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Oxidative stress and endoplasmic reticulum (ER) stress are emerging as crucial events in the etiopathology of many neurodegenerative diseases. While the neuroprotective contributions of the dietary compound curcumin has been recognized, the molecular mechanisms underlying curcumin's neuroprotection under oxidative and ER stresses remains elusive. Herein, we show that curcumin protects HT22 from oxidative and ER stresses evoked by the hypoxia (1% O(2) or CoCl(2) treatment) by enhancing peroxiredoxin 6 (Prdx6) expression. Cells exposed to CoCl(2) displayed reduced expression of Prdx6 with higher reactive oxygen species (ROS) expression and activation of NF-κB with IκB phosphorylation. When NF-κB activity was blocked by using SN50, an inhibitor of NF-κB, or cells treated with curcumin, the repression of Prdx6 expression was restored, suggesting the involvement of NF-κB in modulating Prdx6 expression. These cells were enriched with an accumulation of ER stress proteins, C/EBP homologous protein (CHOP), GRP/78, and calreticulin, and had activated states of caspases 12, 9, and 3. Reinforced expression of Prdx6 in HT22 cells by curcumin reestablished survival signaling by reducing propagation of ROS and blunting ER stress signaling. Intriguingly, knockdown of Prdx6 by antisense revealed that loss of Prdx6 contributed to cell death by sustaining enhanced levels of ER stress-responsive proapoptotic proteins, which was due to elevated ROS production, suggesting that Prdx6 deficiency is a cause of initiation of ROS-mediated ER stress-induced apoptosis. We propose that using curcumin to reinforce the naturally occurring Prdx6 expression and attenuate ROS-based ER stress and NF-κB-mediated aberrant signaling improves cell survival and may provide an avenue to treat and/or postpone diseases associated with ROS or ER stress.
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Affiliation(s)
- Bhavana Chhunchha
- Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, NE 68198, USA
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Zhang Y, Stevenson GD, Barber C, Furenlid LR, Barrett HH, Woolfenden JM, Zhao M, Liu Z. Imaging of rat cerebral ischemia-reperfusion injury using(99m)Tc-labeled duramycin. Nucl Med Biol 2013; 40:80-8. [PMID: 23123139 PMCID: PMC3632380 DOI: 10.1016/j.nucmedbio.2012.09.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 07/31/2012] [Accepted: 09/13/2012] [Indexed: 01/20/2023]
Abstract
OBJECTIVES Prompt identification of necrosis and apoptosis in the infarct core and penumbra region is critical in acute stroke for delineating the underlying ischemic/reperfusion molecular pathologic events and defining therapeutic alternatives. The objective of this study was to investigate the capability of (99m)Tc-labeled duramycin in detecting ischemia-reperfusion injury in rat brain after middle cerebral artery (MCA) occlusion. METHODS Ischemic cerebral injury was induced in ten rats by vascular insertion of a nylon suture in the left MCA for 3 hr followed by 21-24hr reperfusion. After i.v. injection of (99m)Tc-duramycin (1.0-3.5 mCi), dynamic cerebral images were acquired for 1 hr in six rats using a small-animal SPECT imager. Four other rats were imaged at 2 hr post-injection. Ex vivo images were obtained by autoradiography after sacrifice. Histologic analyses were performed to assess cerebral infarction and apoptosis. RESULTS SPECT images showed that (99m)Tc-duramycin uptake in the left cerebral hemisphere was significantly higher than that in the right at 1 and 2 hr post-injection. The level of radioactive uptake in the ischemic brain varied based on ischemic severity. The average ratio of left cerebral hot-spot uptake to right hemisphere radioactivity, as determined by computerized ROI analysis, was 4.92±0.79. Fractional washout at 1 hr was 38.2±4.5% of peak activity for left cerebral hot-spot areas and 80.9±2.0% for remote control areas (P<0.001). Based on triphenyltetrazolium chloride staining and autoradiograph image data, the hotspot uptake may be associated primarily with the ischemic penumbra, in which high apoptotic activity was observed by cleaved caspase-3 immunocytochemical staining. CONCLUSIONS (99m)Tc-duramycin SPECT imaging may be useful for detecting and quantifying ongoing apoptotic neuronal cell loss induced by ischemia-reperfusion injury.
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Affiliation(s)
- Yuqing Zhang
- Department of Medical Imaging, The University of Arizona, Tucson, AZ 85724–5067, USA
| | - Gail D. Stevenson
- Department of Medical Imaging, The University of Arizona, Tucson, AZ 85724–5067, USA
| | - Christy Barber
- Department of Medical Imaging, The University of Arizona, Tucson, AZ 85724–5067, USA
| | - Lars R. Furenlid
- Department of Medical Imaging, The University of Arizona, Tucson, AZ 85724–5067, USA
| | - Harrison H. Barrett
- Department of Medical Imaging, The University of Arizona, Tucson, AZ 85724–5067, USA
| | - James M. Woolfenden
- Department of Medical Imaging, The University of Arizona, Tucson, AZ 85724–5067, USA
| | - Ming Zhao
- Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Zhonglin Liu
- Department of Medical Imaging, The University of Arizona, Tucson, AZ 85724–5067, USA
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Galvao J, Davis BM, Cordeiro MF. In vivo imaging of retinal ganglion cell apoptosis. Curr Opin Pharmacol 2012; 13:123-7. [PMID: 22995681 DOI: 10.1016/j.coph.2012.08.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 08/27/2012] [Accepted: 08/28/2012] [Indexed: 01/24/2023]
Abstract
Apoptosis, or programmed cell death, plays a vital role in normal development and ageing. However, dysregulation of this process is responsible for many disease states including; cancer, autoimmune and neurodegeneration. For this reason, in vivo visualisation of apoptosis may prove a useful tool for both laboratory research and clinical diagnostics. Glaucoma comprises a distinctive group of chronic optic neuropathies, characterised by the progressive loss of retinal ganglion cells (RGCs). Early diagnosis of glaucoma remains a clear and unmet need. Recently, there have been significant advances in the detection of apoptosis in vivo using fluorescent probes to visualise single RGCs undergoing apoptosis, specifically DARC (Detection of Apoptotic Retinal Cells) [1] and capQ technology [2(••)].
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Affiliation(s)
- Joana Galvao
- Glaucoma & Retinal Neurodegeneration Research Group, University College London, London EC1 V9EL, UK
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"Hot spots" in the brain: tissue to be rescued? Crit Care Med 2012; 40:1996-7. [PMID: 22610223 DOI: 10.1097/ccm.0b013e31825457b8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Phagocytic activity of neuronal progenitors regulates adult neurogenesis. Nat Cell Biol 2011; 13:1076-83. [PMID: 21804544 DOI: 10.1038/ncb2299] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Accepted: 06/15/2011] [Indexed: 12/17/2022]
Abstract
Whereas thousands of new neurons are generated daily during adult life, only a fraction of them survive and become part of neural circuits; the rest die, and their corpses are presumably cleared by resident phagocytes. How the dying neurons are removed and how such clearance influences neurogenesis are not well understood. Here, we identify an unexpected phagocytic role for the doublecortin (DCX)-positive neuronal progenitor cells during adult neurogenesis. Our in vivo and ex vivo studies demonstrate that DCX(+) cells comprise a significant phagocytic population within the neurogenic zones. Intracellular engulfment protein ELMO1, which promotes Rac activation downstream of phagocytic receptors, was required for phagocytosis by DCX(+) cells. Disruption of engulfment in vivo genetically (in Elmo1-null mice) or pharmacologically (in wild-type mice) led to reduced uptake by DCX(+) cells, accumulation of apoptotic nuclei in the neurogenic niches and impaired neurogenesis. Collectively, these findings indicate a paradigm wherein DCX(+) neuronal precursors also serve as phagocytes, and that their phagocytic activity critically contributes to neurogenesis in the adult brain.
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Assadi M, Nemati R, Nabipour I, Salimipour H, Amini A. Radiolabeled annexin V imaging: a useful technique for determining apoptosis in multiple sclerosis. Med Hypotheses 2011; 77:43-6. [PMID: 21440374 DOI: 10.1016/j.mehy.2011.03.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/03/2011] [Accepted: 03/07/2011] [Indexed: 11/18/2022]
Abstract
Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) that involves myelin, oligodendrocytes and axons and culminates in consecutive neuronal death and progressive neurologic disability. Based on magnetic resonance imaging (MRI), neuroaxonal loss in MS results in brain atrophy and has a strong correlation with neurological disability. The newer MR imaging tools seem to be sensitive biomarkers for measuring the pathogenetic processes associated with disease activity and progression. However, they are unable to detect apoptosis in neurodegenerative diseases. Annexin V has a high affinity for phosphatidylserine (PS) that presents on the outer surface of the plasma membrane early on during the onset of apoptosis. Radiolabeled annexin V imaging may reveal the initiation and degree of neuronal apoptosis. We propose that radiolabeled annexin V imaging is a useful modality in determining apoptosis in MS and can assess and monitor the effectiveness of neuroprotective and immunomodulatory therapies on the clinical course of MS.
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Affiliation(s)
- Majid Assadi
- The Persian Gulf Nuclear Medicine Research Center, Bushehr University of Medical Sciences, Bushehr, Iran.
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De Saint-Hubert M, Mottaghy FM, Vunckx K, Nuyts J, Fonge H, Prinsen K, Stroobants S, Mortelmans L, Deckers N, Hofstra L, Reutelingsperger CPM, Verbruggen A, Rattat D. Site-specific labeling of 'second generation' annexin V with 99mTc(CO)3 for improved imaging of apoptosis in vivo. Bioorg Med Chem 2010; 18:1356-63. [PMID: 20053567 DOI: 10.1016/j.bmc.2009.12.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 12/06/2009] [Accepted: 12/08/2009] [Indexed: 12/29/2022]
Abstract
In this study 'second generation' AnxV was specifically labeled with (99m)Tc in three different ways outside the binding region of the protein to obtain an improved target-to-background activity ratio. The compounds were tested in vitro and in vivo in normal mice and in a model of hepatic apoptosis (anti-Fas mAb). The apoptosis binding was most prominent for the HIS-tagged 'second generation' AnxV labeled with (99m)Tc(CO)(3) in comparison to (99m)Tc-HYNIC-cys-AnxV and (99m)Tc(CO)(3)-DTPA-cys-AnxV.
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Affiliation(s)
- Marijke De Saint-Hubert
- Department of Nuclear Medicine, University Hospital Gasthuisberg Leuven, Herestraat 49, B-3000 Leuven, Belgium
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Zhang X, Paule MG, Newport GD, Zou X, Sadovova N, Berridge MS, Apana SM, Hanig JP, Slikker W, Wang C. A minimally invasive, translational biomarker of ketamine-induced neuronal death in rats: microPET Imaging using 18F-annexin V. Toxicol Sci 2009; 111:355-61. [PMID: 19638431 DOI: 10.1093/toxsci/kfp167] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
It has been reported that suppression of N-methyl-D-aspartate (NMDA) receptor function by ketamine may trigger apoptosis of neurons when given repeatedly during the brain growth spurt period. Because microPET scans can provide in vivo molecular imaging at sufficient resolution, it has been proposed as a minimally invasive method for detecting apoptosis using the tracer (18)F-labeled annexin V. In this study, the effect of ketamine on the metabolism and integrity of the rat brain were evaluated by investigating the uptake and retention of (18)F-fluorodeoxyglucose (FDG) and (18)F-annexin V using microPET imaging. On postnatal day (PND) 7, rat pups in the experimental group were exposed to six injections of ketamine (20 mg/kg at 2-h intervals) and control rat pups received six injections of saline. On PND 35, 37 MBq (1 mCi) of (18)F-FDG or (18)F-annexin V was injected into the tail vein of treated and control rats, and static microPET images were obtained over 1 (FDG) and 2 h (annexin V) following the injection. No significant difference was found in (18)F-FDG uptake in the regions of interest (ROIs) in the brains of ketamine-treated rats compared with saline-treated controls. The uptake of (18)F-annexin V, however, was significantly increased in the ROI of ketamine-treated rats. Additionally, the duration of annexin V tracer washout was prolonged in the ketamine-treated animals. These results demonstrate that microPET imaging is capable of distinguishing differences in retention of (18)F-annexin V in different brain regions and suggests that this approach may provide a minimally invasive biomarker of neuronal apoptosis in rats.
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Affiliation(s)
- Xuan Zhang
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas 72079, USA
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Abstract
Since its original description in 1972, apoptosis or programmed cell death has been recognized as the major pathway by which the body precisely regulates the number and type of its cells as part of normal embryogenesis, development, and homeostasis. Later it was found that apoptosis was also involved in the pathogenesis of a number of human diseases, cell immunity, and the action of cytotoxotic drugs and radiation therapy in cancer treatment. As such, the imaging of apoptosis with noninvasive techniques such as with radiotracers, including annexin V and lipid proton magnetic resonance spectroscopy, may have a wide range of clinical utility in both the diagnosis and monitoring therapy of a wide range of human disorders. In this chapter we review the basic biochemical and morphologic features of apoptosis and the methods developed thus far to image this complex process in humans.
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Affiliation(s)
- H William Strauss
- Memorial Sloan Kettering Hospital, 1275 York Ave., Room S-212, Nuclear Medicine, New York, NY 10021, USA.
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Liu CH, Huang S, Kim YR, Rosen BR, Liu PK. Forebrain Ischemia-Reperfusion Simulating Cardiac Arrest in Mice Induces Edema and DNA Fragmentation in the Brain. Mol Imaging 2007. [DOI: 10.2310/7290.2007.00011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Christina H. Liu
- From the A.A. Martinos Center for Biomedical Imaging Charlestown, MA; the Transcript Imaging and NeuroRepair Laboratory, Department of Radiology, Massachusetts General Hospital Charlestown, MA; and Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA
| | - Shuning Huang
- From the A.A. Martinos Center for Biomedical Imaging Charlestown, MA; the Transcript Imaging and NeuroRepair Laboratory, Department of Radiology, Massachusetts General Hospital Charlestown, MA; and Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA
| | - Young R. Kim
- From the A.A. Martinos Center for Biomedical Imaging Charlestown, MA; the Transcript Imaging and NeuroRepair Laboratory, Department of Radiology, Massachusetts General Hospital Charlestown, MA; and Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA
| | - Bruce R. Rosen
- From the A.A. Martinos Center for Biomedical Imaging Charlestown, MA; the Transcript Imaging and NeuroRepair Laboratory, Department of Radiology, Massachusetts General Hospital Charlestown, MA; and Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA
| | - Philip K. Liu
- From the A.A. Martinos Center for Biomedical Imaging Charlestown, MA; the Transcript Imaging and NeuroRepair Laboratory, Department of Radiology, Massachusetts General Hospital Charlestown, MA; and Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA
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Lorberboym M, Blankenberg FG, Sadeh M, Lampl Y. In vivo imaging of apoptosis in patients with acute stroke: correlation with blood-brain barrier permeability. Brain Res 2006; 1103:13-9. [PMID: 16806116 DOI: 10.1016/j.brainres.2006.05.073] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Revised: 05/11/2006] [Accepted: 05/15/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND We wished to determine the ability of radiolabeled annexin V to concentrate at sites of ischemic injury in patients with acute cerebral stroke. Secondly, we sought to correlate annexin V imaging in these patients with the degree of blood-brain barrier (BBB) breakdown. METHODS Twelve patients with acute stroke had a complete neurological examination, including the National Institutes of Health (NIH) stroke scale and the Glasgow Coma Score (GCS). A non-contrast CT scan was performed on all patients. A SPECT of the brain was obtained 2 h after injection of annexin V. The integrity of the BBB was evaluated in seven patients using Tc-99m-DTPA brain SPECT. RESULTS All patients had an infarct in the MCA territory. Eight patients had abnormal increased annexin V activity, which was more common in patients with cortical strokes (P = 0.01). The concentration of annexin had no correlation to the volume of stroke, but it was significantly and inversely related to the GCS on admission (r = -0.7, P = 0.02). Foci of apoptosis were noted contralateral to the affected hemisphere as well. All seven patients who underwent DTPA SPECT showed breakdown of the BBB. DTPA uptake was significantly and positively associated with NIH score (r = 0.80, P = 0.01) and inversely associated with GCS (r = -0.89, P = -0.03). CONCLUSION This study shows that it is possible to identify in vivo regions of ischemic neuronal injury using radiolabeled annexin V in patients with acute stroke. Annexin imaging can play a major role in the selection of therapy in the initial period following stroke in adults.
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Affiliation(s)
- Mordechai Lorberboym
- Department of Nuclear Medicine of the Edith Wolfson Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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Blankenberg FG, Kalinyak J, Liu L, Koike M, Cheng D, Goris ML, Green A, Vanderheyden JL, Tong DC, Yenari MA. 99mTc-HYNIC-annexin V SPECT imaging of acute stroke and its response to neuroprotective therapy with anti-Fas ligand antibody. Eur J Nucl Med Mol Imaging 2006; 33:566-74. [PMID: 16477433 DOI: 10.1007/s00259-005-0046-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Accepted: 11/21/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE The first aim of the study was to determine whether (99m)Tc-HYNIC-annexin V, a marker of cellular stress and apoptosis, can detect ischemic injury in patients with acute stroke. Secondly, we wished to test radiolabeled annexin's ability to monitor therapy in a rodent model of focal ischemic injury. METHODS SPECT imaging of patients was performed between 1 and 2 h after intravenous injection of 30 mCi (1,110 MBq) of tracer. Eight MFL4 (anti-FasL) antibody-treated (400 microg i.p. days 0 and 3) and 21 control adult male Sprague-Dawley rats underwent small animal SPECT imaging with 5-10 mCi (185-370 MBq) of tracer, 1 and 6 days after a 2-h intraluminal thread occlusion of the left middle cerebral artery. RESULTS Two patients with acute stroke had regions of multifocal annexin uptake that correlated with sites of restricted diffusion on MRI. Anti-FasL antibody treatment significantly reduced annexin uptake by 92% with a 60% decrease in the number of caspase-8 staining (apoptotic) neurons on day 1. On day 6, treated animals had an 80% reduction in tracer uptake with a 75% decrease in infarct size as compared with controls. Annexin uptake in controls and treated animals (day 6) linearly correlated with infarct size (r (2)=0.603, p=0.0036) and the number of TUNEL-positive (apoptotic) nuclei (r (2)=0.728, p=0.00084). CONCLUSION Annexin imaging shows foci of increased uptake at sites of ischemic injury in patients with acute stroke. Annexin imaging can assess the effects of therapy for ischemic cerebral injury in rats, suggesting its potential as a non-invasive indicator of drug efficacy in future clinical trials.
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Affiliation(s)
- Francis G Blankenberg
- Division of Pediatric Radiology/Department of Radiology, Stanford University Hospital, 725 Welch Road, Rm #1673, Lucile Packard Children's Hospital, Palo Alto, CA 94305, USA.
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Dekker B, Keen H, Shaw D, Disley L, Hastings D, Hadfield J, Reader A, Allan D, Julyan P, Watson A, Zweit J. Functional comparison of annexin V analogues labeled indirectly and directly with iodine-124. Nucl Med Biol 2005; 32:403-13. [PMID: 15878510 DOI: 10.1016/j.nucmedbio.2005.02.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2004] [Revised: 01/25/2005] [Accepted: 02/06/2005] [Indexed: 11/28/2022]
Abstract
We are interested in imaging cell death in vivo using annexin V radiolabeled with (124)I. In this study, [(124)I]4IB-annexin V and [(124)I]4IB-ovalbumin were made using [(124)I]N-hydroxysuccinimidyl-4-iodobenzoate prepared by iododestannylation of N-hydroxysuccinimidyl-4-(tributylstannyl)benzoate. [(124)I]4IB-annexin V binds to phosphatidylserine-coated microtiter plates and apoptotic Jurkat cells and accumulates in hepatic apoptotic lesions in mice treated with anti-Fas antibody, while [(124)I]4IB-ovalbumin does not. In comparison with (124)I-annexin V, [(124)I]4IB-annexin V has a higher rate of binding to phosphatidylserine in vitro, a higher kidney and urine uptake, a lower thyroid and stomach content uptake, greater plasma stability and a lower rate of plasma clearance. Binding of radioactivity to apoptotic cells relative to normal cells in vitro and in vivo appears to be lower for [(124)I]4IB-annexin V than for (124)I-annexin V.
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Affiliation(s)
- Bronwen Dekker
- CRUK/UMIST Department of Radiochemical Targeting and Imaging, Paterson Institute for Cancer Research, M20 4BX Manchester, UK.
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22
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Dekker B, Keen H, Lyons S, Disley L, Hastings D, Reader A, Ottewell P, Watson A, Zweit J. MBP-annexin V radiolabeled directly with iodine-124 can be used to image apoptosis in vivo using PET. Nucl Med Biol 2005; 32:241-52. [PMID: 15820759 DOI: 10.1016/j.nucmedbio.2004.11.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 09/21/2004] [Accepted: 11/17/2004] [Indexed: 11/21/2022]
Abstract
A noninvasive method of measuring programmed cell death in the tumors of cancer patients using positron-emission tomography (PET) would provide valuable information regarding their response to therapeutic intervention. Our strategy is to radiolabel annexin V, a protein that binds to phosphatidylserine moieties that are translocated to the external leaflet of plasma membranes during apoptosis. We developed a phosphatidylserine-ELISA capable of distinguishing wild type from point mutant annexin V that is known to have a lower phosphatidylserine binding affinity. A maltose-binding protein/annexin V chimera was synthesized and purified with high yield using amylose resin. We showed that it bound to phosphatidylserine in the ELISA as well as to that exposed on apoptotic Jurkat cells; therefore, it was used in the development of a method for radiolabeling annexin V using iodine radionuclides. MBP-annexin V retained its phosphatidylserine binding properties on direct iodination, but at high levels of oxidizing agents (iodogen and chloramine T), its specificity for phosphatidylserine was compromised. (124)I-MBP-annexin V was successfully used to image Fas-mediated hepatic cell death in BDF-1 mice using PET. In conclusion, we have shown that MBP-annexin V and the phosphatidylserine ELISA are useful tools for the development of methods for radiolabeling annexin V for PET imaging.
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Affiliation(s)
- Bronwen Dekker
- Cancer Research UK/UMIST, Department of Radiochemical Targeting and Imaging, Paterson Institute for Cancer Research, M20 4BX Manchester, UK
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Jarskog LF, Glantz LA, Gilmore JH, Lieberman JA. Apoptotic mechanisms in the pathophysiology of schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2005; 29:846-58. [PMID: 15908096 DOI: 10.1016/j.pnpbp.2005.03.010] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/01/2005] [Indexed: 10/25/2022]
Abstract
While schizophrenia is generally considered a neurodevelopmental disorder, evidence for progressive clinical deterioration and subtle neurostructural changes following the onset of psychosis has led to the hypothesis that apoptosis may contribute to the pathophysiology of schizophrenia. Apoptosis (a.k.a. programmed cell death) is a mechanism of cell death that operates in normal neurodevelopment and is increasingly recognized for its role in diverse neuropathological conditions. Activation of apoptosis can lead to rapid and complete elimination of neurons and glia in the central nervous system. Studies also show that in certain settings, pro-apoptotic triggers can lead to non-lethal and localized apoptotic activity that produces neuritic and synaptic loss without causing cell death. Given that the neuropathology of schizophrenia is subtle and includes reduced neuropil (especially synaptic elements), limited and often layer-specific reductions of neurons, as well as neuroimaging data suggesting progressive loss of cortical gray matter in first-episode psychosis, a role for apoptosis in schizophrenia appears plausible. Studies that have examined markers of apoptosis and levels of apoptotic regulatory proteins in postmortem schizophrenia brain tissue will be reviewed in context of this hypothesis. Overall, the data seem to indicate a dysregulation of apoptosis in several cortical regions in schizophrenia, including evidence that the apoptotic vulnerability is increased. Although the exact role of apoptosis in schizophrenia remains uncertain, the potential involvement of non-lethal localized apoptosis is intriguing, especially in earlier stages of the illness.
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Affiliation(s)
- L Fredrik Jarskog
- Department of Psychiatry, Schizophrenia Research Center, University of North Carolina-Chapel Hill, CB# 7160, Chapel Hill, NC 27599-7160, USA.
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Toretsky J, Levenson A, Weinberg IN, Tait JF, Uren A, Mease RC. Preparation of F-18 labeled annexin V: a potential PET radiopharmaceutical for imaging cell death. Nucl Med Biol 2005; 31:747-52. [PMID: 15246365 DOI: 10.1016/j.nucmedbio.2004.02.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Revised: 02/06/2004] [Accepted: 02/23/2004] [Indexed: 11/28/2022]
Abstract
The clinical response to antitumor therapy is measured using imaging, such as CT or MRI, 6-12 weeks following chemotherapy treatment. The images at that time reflect both tumor cell death and new growth. Therefore, the amount of tumor cell death caused by chemotherapy cannot be efficiently quantified with current imaging modalities. A quantitative measurement of tumor cell death immediately following chemotherapy is needed to help validate both new agents and to optimize administration of existing therapies. Annexin V is a 36kD protein that binds to exposed phosphatidylserine (PS) on dying cells. In order to synthesize a probe that can detect cell death in vivo, the positron emitter F-18 was conjugated to annexin V via the compound N- succinimidyl-4-[18F]fluorobenzoate, [18F]SFB. The decay corrected radiochemical yield of F-18 labeled annexin V from 18F fluoride was 17.6 +/- 5.6% (n = 4) in three hours. The stepwise radiochemical yield of the conjugation step with annexin V was as high as 70% when a protein concentration of 5 mg/ml was used. Cancer cells treated with the chemotherapeutic agent, etoposide, showed an 88% increase in the binding of F-18 labeled annexin V compared to untreated cells. We conclude that [18F] labeled annexin V can be readily prepared by the conjugation of annexin V with [18F]SFB and that the positron-emitting compound is biologically active in detecting apoptosis.
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Affiliation(s)
- J Toretsky
- Georgetown University, Washington, DC 20007, USA.
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D'Arceuil HE, Hotakainen MP, Liu C, Themelis G, de Crespigny AJ, Franceschini MA. Near-infrared frequency-domain optical spectroscopy and magnetic resonance imaging: a combined approach to studying cerebral maturation in neonatal rabbits. JOURNAL OF BIOMEDICAL OPTICS 2005; 10:11011. [PMID: 15847577 PMCID: PMC2637814 DOI: 10.1117/1.1852554] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The neonatal rabbit brain shows prolonged postnatal development both structurally and physiologically. We use noninvasive near-IR frequency-domain optical spectroscopy (NIRS) and magnetic resonance imaging (MRI) to follow early developmental changes in cerebral oxygenation and anatomy, respectively. Four groups of animals are measured: NIRS in normals, MRI in normals, and both NIRS and MRI with hypoxia-ischemia (HI) (diffusion MRI staging). NIRS and/or MRI are performed from P3 (postnatal day=P) up to P76. NIRS is performed on awake animals with a frequency-domain tissue photometer. Absolute values of oxyhemoglobin concentration ([HbO2]), deoxyhemoglobin concentration ([HbR]), total hemoglobin concentration (HbT), and hemoglobin saturation (StO2) are calculated. The brains of all animals appeared to be maturing as shown in the diffusion tensor MRI. Mean optical coefficients (reduced scattering) remained unchanged in all animals throughout. StO2 increased in all animals (40% at P9 to 65% at P43) and there are no differences between normal, HI controls, and HI brains. The measured increase in StO2 is in agreement with the reported increase in blood flow during the first 2 months of life in rabbits. HbT, which reflects blood volume, peaked at postnatal day P17, as expected since the capillary density increases up to P17 when the microvasculature matures.
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Affiliation(s)
- H E D'Arceuil
- Neuroradiology Section, Martinos Center for Biomedical Imaging, Room 2301, Building 149, 13th Street, Charlestown, Massachusetts 02129, USA.
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Ke X, McKnight RA, Wang ZM, Yu X, Wang L, Callaway CW, Albertine KH, Lane RH. Nonresponsiveness of cerebral p53-MDM2 functional circuit in newborn rat pups rendered IUGR via uteroplacental insufficiency. Am J Physiol Regul Integr Comp Physiol 2004; 288:R1038-45. [PMID: 15563574 DOI: 10.1152/ajpregu.00701.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Severe uteroplacental insufficiency causes cerebral apoptosis in the fetus. Moderate uteroplacental insufficiency causes intrauterine growth retardation (IUGR) and increases the risk of postnatal neurological morbidity. In the rat, uteroplacental insufficiency and IUGR affect cerebral gene expression of Bcl-2 and predispose the newborn IUGR rat toward cerebral apoptosis when challenged with perinatal hypoxia. Expression of Bcl-2, as well as the proapoptotic protein Bax, is regulated by p53. p53 also induces MDM2 transcription, which functions to limit further p53-induced apoptosis. The predisposition of the IUGR fetus toward cerebral apoptosis suggests that the p53-MDM2 "functional" circuit may be perturbed in the newborn IUGR rat brain. We hypothesized that MDM2 cerebral expression does not increase in response to increased p53 expression or increased levels of phospho-p53 (Ser15), an activated form of p53. To prove this hypothesis, we induced IUGR through bilateral uterine ligation of the pregnant rat. Uteroplacental insufficiency significantly increased p53 mRNA, total p53 protein, and phospho-p53 (Ser15) protein levels in the brain at term. Increased expression of phospho-p53 (Ser15) and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive cells were localized to the CA1 region of the hippocampus, the subcortical and periventricular white matter, and the amygdala of the IUGR rat brain. In contrast, uteroplacental insufficiency decreased cerebral MDM2 mRNA and phospho-MDM2 (Ser166) protein levels in the IUGR rat pups. We conclude that the cerebral MDM2 response to increased p53 expression is not present in the newborn IUGR rat pup, and we speculate that this contributes to the predisposition of the IUGR fetus toward perinatal and long-term neurodevelopmental morbidities.
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Affiliation(s)
- Xingrao Ke
- Division of Neonatology, Department of Pediatrics, University of Utah School of Medicine, 30 North 1900 East, Rm. 2A100, Salt Lake City, UT 84132-2202, USA
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Rutherford M, Counsell S, Allsop J, Boardman J, Kapellou O, Larkman D, Hajnal J, Edwards D, Cowan F. Diffusion-weighted magnetic resonance imaging in term perinatal brain injury: a comparison with site of lesion and time from birth. Pediatrics 2004; 114:1004-14. [PMID: 15466098 DOI: 10.1542/peds.2004-0222] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE The aim of this study was to establish a more objective method for confirming tissue injury in term neonates who present with early seizures that are believed to be hypoxic-ischemic in origin. METHODS We studied the relationship between contemporaneous diffusion-weighted magnetic resonance imaging and conventional magnetic resonance imaging in 63 symptomatic term-born neonates and 15 control term infants performed in the neonatal period. Apparent diffusion coefficients (ADC) were obtained for multiple regions of the brain. RESULTS ADC values in the 15 control infants were 1 (1-1.15) (median [range]) x 10(-3)/mm2/second in the thalami and 1.1 (1-1.3) x 10(-3)/mm2/second in the lentiform nuclei, 1.5 (1.3-1.7) x 10(-3)/mm2/second in the centrum semiovale, 1.6 (1.46-1.7) x 10(-3)/mm2/second in the anterior white matter (WM), and 1.55 (1.35-1.85) x 10(-3)/mm2/second in the posterior WM with little variation over time. ADC values were significantly reduced in the first week after severe injury to either WM or basal ganglia and thalami (BGT), but values normalized at the end of the first week and then increased during week 2. ADC values were either normal or increased in moderate BGT and WM lesions when compared with controls. ADC values < 1.1 x 10(-3)/mm2/second were always associated with WM infarction and values <0.8 x 10(-3)/mm2/second with thalamic infarction. CONCLUSION A reduced ADC soon after delivery allows the presence of tissue infarction to be confirmed at a time when conventional imaging changes may be subtle. However, as both moderate WM and BGT lesions may have normal or increased ADC values, a normal ADC value during the first week does not signify normal tissue. ADC values should always be measured in combination with visual analysis of both conventional and diffusion-weighed images for maximum detection of pathologic tissue, and the timing of the scan needs to be taken into account when interpreting the results.
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Affiliation(s)
- Mary Rutherford
- Robert Steiner MR Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Imperial College, Hammersmith Hospital, Du Cane Rd, London W12 OHS.
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Takuma K, Baba A, Matsuda T. Astrocyte apoptosis: implications for neuroprotection. Prog Neurobiol 2004; 72:111-27. [PMID: 15063528 DOI: 10.1016/j.pneurobio.2004.02.001] [Citation(s) in RCA: 350] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2003] [Accepted: 02/04/2004] [Indexed: 12/21/2022]
Abstract
Astrocytes, the most abundant glial cell types in the brain, provide metabolic and trophic support to neurons and modulate synaptic activity. Accordingly, impairment in these astrocyte functions can critically influence neuronal survival. Recent studies show that astrocyte apoptosis may contribute to pathogenesis of many acute and chronic neurodegenerative disorders, such as cerebral ischemia, Alzheimer's disease and Parkinson's disease. We found that incubation of cultured rat astrocytes in a Ca(2+)-containing medium after exposure to a Ca(2+)-free medium causes an increase in intracellular Ca(2+) concentration followed by apoptosis, and that NF-kappa B, reactive oxygen species, and enzymes such as calpain, xanthine oxidase, calcineurin and caspase-3 are involved in reperfusion-induced apoptosis. Furthermore, we demonstrated that heat shock protein, mitogen-activated protein/extracellular signal-regulated kinase, phosphatidylinositol-3 kinase and cyclic GMP phosphodiesterase are target molecules for anti-apoptotic drugs. This review summarizes (1) astrocytic functions in neuroprotection, (2) current evidence of astrocyte apoptosis in both in vitro and in vivo studies including its molecular pathways such as Ca(2+) overload, oxidative stress, NF-kappa B activation, mitochondrial dysfunction, endoplasmic reticulum stress, and protease activation, and (3) several drugs preventing astrocyte apoptosis. As a whole, this article provides new insights into the potential role of astrocytes as targets for neuroprotection. In addition, the advance in the knowledge of molecular mechanisms of astrocyte apoptosis may lead to the development of novel therapeutic strategies for neurodegenerative disorders.
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Affiliation(s)
- Kazuhiro Takuma
- Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences and High Technology Research Center, Kobe Gakuin University, Kobe 651-2180, Japan
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Fujita Y, Yamamoto N, Sobue K, Inagaki M, Ito H, Arima H, Morishima T, Takeuchi A, Tsuda T, Katsuya H, Asai K. Effect of mild hypothermia on the expression of aquaporin family in cultured rat astrocytes under hypoxic condition. Neurosci Res 2003; 47:437-44. [PMID: 14630348 DOI: 10.1016/j.neures.2003.08.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Aquaporins (AQPs) are a family of water-selective transporting proteins with homology to the major intrinsic protein (MIP) of lens, that increase plasma membrane water permeability in secretory and absorptive cells. In this study, we investigated the effect of mild hypothermia on the expression of AQP4, AQP5 and AQP9 in rat astrocytes cultured under hypoxic conditions. At 37 degrees C, a marked decrease in the expression of AQP4, AQP5 and AQP9 mRNAs was observed. However, at 32 degrees C (mild hypothermia), the expression of AQP5 mRNA was restored to its basal level. Interestingly, under mild hypothermia AQP4 mRNA expression transiently decreased and then increased about two-fold; while AQP9 mRNA expression decreased the same as at 37 degrees C. The changes in the expression of AQP4 and AQP9 proteins were confirmed by Western blot analysis. The restoration of the AQP4 and AQP5 expression at 32 degrees C from the hypoxia-induced decrease at 37 degrees C may play an important role in the reduction of brain edema under hypothermic conditions.
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Affiliation(s)
- Yoshihito Fujita
- Department of Anesthesiology and Medical Crisis Management, Nagoya City University Graduate School of Medical Sciences, Mizuho-ku, Nagoya 467-8901, Japan
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Sarikaya I, Larson SM, Freiman A, Strauss HW. What nuclear cardiology can learn from nuclear oncology. J Nucl Cardiol 2003; 10:324-8. [PMID: 12794632 DOI: 10.1016/s1071-3581(03)00521-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Ismet Sarikaya
- Section of Nuclear Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
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Flotats A, Carrió I. Non-invasive in vivo imaging of myocardial apoptosis and necrosis. Eur J Nucl Med Mol Imaging 2003; 30:615-30. [PMID: 12638039 DOI: 10.1007/s00259-003-1136-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Myocardial necrosis plays an important role in the pathogenesis of various cardiovascular disorders and can result from different myocardial insults. Its non-invasive identification and localisation therefore may help in the diagnosis of these disorders, as well as in prognosis and assessment of treatment response. Apoptosis, or programmed cell death, is important in the spectrum of myocardial damage since it is gradually becoming more apparent that cell death may begin as apoptosis and not as necrosis. First attempts to directly visualise the area of myocardial necrosis were based on recognition of myocardial infarction with "hot spot imaging agents" in patients with chest pain. Since then, the study of myocardial necrosis with gamma imaging agents has gone beyond the detection of myocardial infarction, and attempts have been made to diagnose other cardiovascular disorders associated with cardiac cell death such as heart transplant rejection, myocarditis, cardiotoxicity and cardiomyopathies. Traditionally, two hot spot imaging agents have been used for the detection of myocardial necrosis, (99m)Tc-pyrophosphate and (111)In-antimyosin. In addition, preliminary studies have demonstrated promising results with (99m)Tc-glucarate. Recently, (99m)Tc-annexin V has been successfully used for non-invasive gamma imaging of apoptosis after acute myocardial infarction, acute myocardial ischaemia, acute cardiac allograft rejection and malignant intracardiac tumours. This review article focusses on the characteristics of these different myocardial necrotic and apoptotic markers and compares their role in the assessment of myocardial damage.
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Signore A, Annovazzi A, Corsetti F, Capriotti G, Chianelli M, De Winter F, Scopinaro F. Biological imaging for the diagnosis of inflammatory conditions. BioDrugs 2003; 16:241-59. [PMID: 12196038 DOI: 10.2165/00063030-200216040-00002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Radiopharmaceuticals used for in vivo imaging of inflammatory conditions can be conveniently classified into six categories according to the different phases in which the inflammatory process develops. The trigger of an inflammatory process is a pathogenic insult (phase I) that causes activation of endothelial cells (phase II); there is then an increase of vascular permeability followed by tissue oedema (phase III). Phase IV is characterised by infiltration of polymorphonuclear cells, and a self-limiting regulatory process called apoptosis is observed (phase V). If the inflammatory process persists, late chronic inflammation takes place (phase VI). In some pathological conditions, such as organ-specific autoimmune diseases, chronic inflammation is present early in the disease. The aim of nuclear medicine in the field of inflammation/infection is to develop noninvasive tools for the in vivo detection of specific cells and tissues. This would allow early diagnosis of initial pathophysiological changes that are undetectable by clinical examination or by other diagnostic tools, and could also be used to evaluate the state of activity of the disease during therapy. These potential applications are of great interest in clinical practice. In this review, we describe the various approaches that have been developed in the last 25 years of experience. Recent advances in the diagnosis of inflammatory processes have led to the development of specific radiopharmaceuticals that are intended to allow specific stage-related diagnosis.
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Affiliation(s)
- Alberto Signore
- Department of Clinical Sciences, Nuclear Medicine, 2nd Faculty of Medicine, University of Rome, La Sapienza, Rome, Italy.
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Zarifi MK, Astrakas LG, Poussaint TY, Plessis Ad AD, Zurakowski D, Tzika AA. Prediction of adverse outcome with cerebral lactate level and apparent diffusion coefficient in infants with perinatal asphyxia. Radiology 2002; 225:859-70. [PMID: 12461272 DOI: 10.1148/radiol.2253011797] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To compare the predictive value for adverse outcome of quantitative cerebral lactate level and of apparent diffusion coefficient (ADC) in infants with perinatal asphyxia in the early postnatal period. MATERIALS AND METHODS Lactate-choline ratios determined with proton magnetic resonance (MR) spectroscopy and ADC determined with diffusion MR imaging in basal ganglia and thalami in 26 full-term neonates (age range, 1-10 days) were compared with severity of acute hypoxic-ischemic encephalopathy and long-term clinical outcome. Differences in metabolites between outcome groups were evaluated with the nonparametric Kruskal-Wallis test and the Dunn test. Logistic regression was performed to examine the predictive value of each metabolite for differentiating normal from abnormal or fatal clinical outcome. The likelihood ratio test was used to assess the statistical significance of each metabolite. RESULTS Logistic regression confirmed that lactate-choline ratio could be used to differentiate normal (n = 5) from abnormal (n = 14) or fatal (n = 6) outcome (P <.001). The probability of an adverse outcome exceeded 95% for a lactate-choline ratio of 1.0. Even when analyses were restricted to the early postnatal period, lactate-choline ratio was still a significant predictor of adverse outcome (P =.001). Although ADC images were useful in clinical examination of these infants, quantitative ADCs were not predictive of outcome (P =.82). CONCLUSION Higher lactate-choline ratios in basal ganglia and thalami of infants with perinatal asphyxia were predictive of worse clinical outcomes. Absolute ADC in the same brain regions did not indicate a statistically significant relationship with clinical outcome. Cerebral lactate level is useful in identifying infants who would benefit from early therapeutic intervention.
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Affiliation(s)
- Maria K Zarifi
- Departments of Radiology, Children's Hospital, Harvard Medical School, Boston, Mass 02114, USA
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Donnan GA, Davis SM. Neuroimaging, the ischaemic penumbra, and selection of patients for acute stroke therapy. Lancet Neurol 2002; 1:417-25. [PMID: 12849364 DOI: 10.1016/s1474-4422(02)00189-8] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Advances in neuroimaging have been central to the expansion of knowledge in the neurosciences over the past 20 years. One of the most important roles of brain imaging is in the selection of patients for acute stroke therapy. Currently, computed tomography (CT) is commonly used to select patients who have had strokes for thrombolytic therapy on the basis of the absence of haemorrhage and, more controversially, the presence of early CT changes of ischaemia. Since patients with ischaemic penumbra are more likely than those without to respond to therapy, identification of patients with this feature will become increasingly important. Although several imaging modalities can identify the penumbra, the most practical is magnetic resonance imaging (MRI) showing perfusion-weighted and diffusion-weighted imaging mismatch. Although uncertainties in image interpretation remain, surrogate MRI outcome measures are becoming an important component of translational research. Future developments in imaging technologies may provide other opportunities for surrogate outcome studies.
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Affiliation(s)
- Geoffrey A Donnan
- National Stroke Research Institute, Austin and Repatriation Medical Centre, University of Melbourne, West Heidelberg, Victoria, Australia.
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Schellenberger EA, Bogdanov A, Högemann D, Tait J, Weissleder R, Josephson L. Annexin V-CLIO: a nanoparticle for detecting apoptosis by MRI. Mol Imaging 2002; 1:102-7. [PMID: 12920851 DOI: 10.1162/15353500200202103] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Annexin V, which recognizes the phosphatidylserine of apoptotic cells, was conjugated to crosslinked iron oxide (CLIO) nanoparticles, a functionalized superparamagnetic preparation developed for target-specific magnetic resonance imaging (MRI). The resulting nanoparticle had an average of 2.7 annexin V proteins linked per CLIO nanoparticle through disulfide bonds. Using camptothecin to induce apoptosis, a mixture of Jurkat T cells (69% healthy and 31% apoptotic) was incubated with annexin V-CLIO and was applied to magnetic columns. The result was an almost complete removal of the apoptotic cells (> 99%). In a phantom MRI experiment, untreated control cells (12% apoptotic cells, 88% healthy cells) and camptothecin-treated cells (65% apoptotic cells, 35% healthy cells) were incubated with either annexin V-CLIO (1.0, 0.5, and 0.1 microgram Fe/mL) or with unlabeled CLIO. A significant signal decrease of camptothecin-treated cells relative to untreated cells was observed even at the lowest concentration tested. Unmodified CLIO failed to cause a significant signal change of apoptotic cells. Hence, annexin V-CLIO allowed the identification of cell suspensions containing apoptotic cells by MRI even at very low concentrations of magnetic substrate. Conjugation of annexin V to CLIO affords a strategy for the development of a MRI imaging probe for detecting apoptosis.
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Abstract
Neonatal stroke occurs in approximately 1 in 4,000 to 1 in 10,000 newborns, and more than 80% involve the vascular territory supplied by the middle cerebral artery. Neonatal stroke is associated with many acquired and genetic prothrombotic factors, and follow-up studies indicate that as many as two thirds of neonates develop neurologic deficits. In the past two decades unilateral carotid occlusion with 8% hypoxia has been used to study focal and global ischemia in the newborn, and recently a filament model of middle cerebral artery occlusion has been developed. This review describes the results of studies in these two newborn models covering aspects of the injury cascade that occurs after focal ischemia. A likely requirement is that therapeutic efforts be directed less at using thrombolytic therapy and more toward treatment of events associated with reperfusion injury, the inflammatory cascade, and apoptosis. Additional areas of research that have received attention in the past year include inhibition of nitric oxide and free-radical formation, use of iron chelating agents, the potential role of hypoxia-inducible factors and mediators of caspase activity, use of growth factors, hypothermia, and administration of magnesium sulfate.
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Affiliation(s)
- S Ashwal
- Department of Pediatrics, Division of Child Neurology, Loma Linda University School of Medicine, Loma Linda, California 12350, USA.
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