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Jiang Y, Han P, Yin G, Wang Q, Feng J, Ruan Q, Xiao D, Zhang J. Radiosynthesis and Bioevaluation of 99mTc-Labeled Isocyanide Ubiquicidin 29-41 Derivatives as Potential Agents for Bacterial Infection Imaging. Int J Mol Sci 2024; 25:1045. [PMID: 38256119 PMCID: PMC10816394 DOI: 10.3390/ijms25021045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/08/2024] [Accepted: 01/13/2024] [Indexed: 01/24/2024] Open
Abstract
To develop a novel 99mTc-labeled ubiquicidin 29-41 derivative for bacterial infection single-photon emission computed tomography (SPECT) imaging with improved target-to-nontarget ratio and lower nontarget organ uptake, a series of isocyanide ubiquicidin 29-41 derivatives (CNnUBI 29-41, n = 5-9) with different carbon linkers were designed, synthesized and radiolabeled with the [99mTc]Tc(I)+ core, [99mTc][Tc(I)(CO)3(H2O)3]+ core and [99mTc][Tc(V)N]2+ core. All the complexes are hydrophilic, maintain good stability and specifically bind Staphylococcus aureus in vitro. The biodistribution in mice with bacterial infection and sterile inflammation demonstrated that [99mTc]Tc-CN5UBI 29-41 was able to distinguish bacterial infection from sterile inflammation, which had an improved abscess uptake and a greater target-to-nontarget ratio. SPECT imaging study of [99mTc]Tc-CN5UBI 29-41 in bacterial infection mice showed that there was a clear accumulation in the infection site, suggesting that this radiotracer could be a potential radiotracer for bacterial infection imaging.
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Affiliation(s)
- Yuhao Jiang
- Key Laboratory of Radiopharmaceuticals of Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), College of Chemistry, Beijing Normal University, Beijing 100875, China; (Y.J.); (P.H.); (G.Y.); (Q.W.); (J.F.); (Q.R.); (D.X.)
| | - Peiwen Han
- Key Laboratory of Radiopharmaceuticals of Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), College of Chemistry, Beijing Normal University, Beijing 100875, China; (Y.J.); (P.H.); (G.Y.); (Q.W.); (J.F.); (Q.R.); (D.X.)
| | - Guangxing Yin
- Key Laboratory of Radiopharmaceuticals of Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), College of Chemistry, Beijing Normal University, Beijing 100875, China; (Y.J.); (P.H.); (G.Y.); (Q.W.); (J.F.); (Q.R.); (D.X.)
| | - Qianna Wang
- Key Laboratory of Radiopharmaceuticals of Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), College of Chemistry, Beijing Normal University, Beijing 100875, China; (Y.J.); (P.H.); (G.Y.); (Q.W.); (J.F.); (Q.R.); (D.X.)
| | - Junhong Feng
- Key Laboratory of Radiopharmaceuticals of Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), College of Chemistry, Beijing Normal University, Beijing 100875, China; (Y.J.); (P.H.); (G.Y.); (Q.W.); (J.F.); (Q.R.); (D.X.)
- Department of Isotopes, China Institute of Atomic Energy, P.O. Box 2108, Beijing 102413, China
| | - Qing Ruan
- Key Laboratory of Radiopharmaceuticals of Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), College of Chemistry, Beijing Normal University, Beijing 100875, China; (Y.J.); (P.H.); (G.Y.); (Q.W.); (J.F.); (Q.R.); (D.X.)
- Key Laboratory of Beam Technology of the Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875, China
| | - Di Xiao
- Key Laboratory of Radiopharmaceuticals of Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), College of Chemistry, Beijing Normal University, Beijing 100875, China; (Y.J.); (P.H.); (G.Y.); (Q.W.); (J.F.); (Q.R.); (D.X.)
| | - Junbo Zhang
- Key Laboratory of Radiopharmaceuticals of Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), College of Chemistry, Beijing Normal University, Beijing 100875, China; (Y.J.); (P.H.); (G.Y.); (Q.W.); (J.F.); (Q.R.); (D.X.)
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Roll W, Faust A, Hermann S, Schäfers M. Infection Imaging: Focus on New Tracers? J Nucl Med 2023; 64:59S-67S. [PMID: 37918846 DOI: 10.2967/jnumed.122.264869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/31/2023] [Indexed: 11/04/2023] Open
Abstract
Infections account for relevant morbidity and mortality, especially if the cardiovascular system is affected. Clinical manifestations are often unspecific, resulting in a challenging diagnostic work-up. The use of molecular imaging methods, namely [18F]FDG PET and leukocyte scintigraphy, is increasingly recognized in recently published international guidelines. However, these 2 established methods focus on the host's immune response to the pathogen and are therefore virtually unable to differentiate infection from inflammation. Targeting the microorganism responsible for the infection directly with novel imaging agents is a promising strategy to overcome these limitations. In this review, we discuss clinically approved [18F]FDG PET with its advantages and limitations in cardiovascular infections, followed by new PET-based approaches for the detection of cardiovascular infections by bacteria-specific molecular imaging methods. A multitude of different targeting options has already been preclinically evaluated, but most still lack clinical translation. We give an overview not only on promising tracer candidates for noninvasive molecular imaging of infections but also on issues hampering clinical translation.
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Affiliation(s)
- Wolfgang Roll
- Department of Nuclear Medicine, University Hospital Münster, Münster, Germany; and
| | - Andreas Faust
- Department of Nuclear Medicine, University Hospital Münster, Münster, Germany; and
- European Institute for Molecular Imaging, University of Münster, Münster, Germany
| | - Sven Hermann
- European Institute for Molecular Imaging, University of Münster, Münster, Germany
| | - Michael Schäfers
- Department of Nuclear Medicine, University Hospital Münster, Münster, Germany; and
- European Institute for Molecular Imaging, University of Münster, Münster, Germany
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Akbari B, Huber BR, Sherman JH. Unlocking the Hidden Depths: Multi-Modal Integration of Imaging Mass Spectrometry-Based and Molecular Imaging Techniques. Crit Rev Anal Chem 2023:1-30. [PMID: 37847593 DOI: 10.1080/10408347.2023.2266838] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
Multimodal imaging (MMI) has emerged as a powerful tool in clinical research, combining different imaging modes to acquire comprehensive information and enabling scientists and surgeons to study tissue identification, localization, metabolic activity, and molecular discovery, thus aiding in disease progression analysis. While multimodal instruments are gaining popularity, challenges such as non-standardized characteristics, custom software, inadequate commercial support, and integration issues with other instruments need to be addressed. The field of multimodal imaging or multiplexed imaging allows for simultaneous signal reproduction from multiple imaging strategies. Intraoperatively, MMI can be integrated into frameless stereotactic surgery. Recent developments in medical imaging modalities such as magnetic resonance imaging (MRI), and Positron Emission Topography (PET) have brought new perspectives to multimodal imaging, enabling early cancer detection, molecular tracking, and real-time progression monitoring. Despite the evidence supporting the role of MMI in surgical decision-making, there is a need for comprehensive studies to validate and perform integration at the intersection of multiple imaging technologies. They were integrating mass spectrometry-based technologies (e.g., imaging mass spectrometry (IMS), imaging mass cytometry (IMC), and Ion mobility mass spectrometry ((IM-IM) with medical imaging modalities, offering promising avenues for molecular discovery and clinical applications. This review emphasizes the potential of multi-omics approaches in tissue mapping using MMI integrated into desorption electrospray ionization (DESI) and matrix-assisted laser desorption ionization (MALDI), allowing for sequential analyses of the same section. By addressing existing knowledge gaps, this review encourages future research endeavors toward multi-omics approaches, providing a roadmap for future research and enhancing the value of MMI in molecular pathology for diagnosis.
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Affiliation(s)
- Behnaz Akbari
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | - Bertrand Russell Huber
- Chobanian and Avedisian School of Medicine, Boston University, Boston, Massachusetts, USA
- Boston University Alzheimer's Disease and CTE Center, Boston University School of Medicine, Boston, Massachusetts, USA
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts, USA
- US Department of Veteran Affairs, VA Boston Healthcare System, Boston, Massachusetts USA
- US Department of Veterans Affairs, National Center for PTSD, Boston, Massachusetts USA
| | - Janet Hope Sherman
- Chobanian and Avedisian School of Medicine, Boston University, Boston, Massachusetts, USA
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MicroPET imaging of bacterial infection with nitroreductase-specific responsive 18F-labelled nitrogen mustard analogues. Eur J Nucl Med Mol Imaging 2022; 49:2645-2654. [PMID: 35122512 DOI: 10.1007/s00259-022-05710-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 01/26/2022] [Indexed: 11/04/2022]
Abstract
PURPOSE Bacterial infection and antibiotic resistance are serious threats to human health. This study aimed to develop two novel radiotracers, 18F-NTRP and 18F-NCRP, that possess a specific nitroreductase (NTR) response to image deep-seated bacterial infections using positron emission tomography (PET). This method can distinguish infection from sterile inflammation. METHODS 18F-NTRP and 18F-NCRP were synthesized via a one-step method; all the steps usually involved in tracer radiosynthesis were successfully adapted in the All-In-One automated module. After the physiochemical properties of 18F-NTRP and 18F-NCRP were characterized, their specificity and selectivity for NTR were verified in E. coli and S. aureus. The ex vivo biodistribution of the tracers was evaluated in normal mice. MicroPET-CT imaging was performed in mouse models of bacterial infection and inflammation after the administration of 18F-NTRP or 18F-NCRP. RESULTS Fully automated radiosynthesis of 18F-NTRP and 18F-NCRP was achieved within 90-110 min with overall decay-uncorrected, isolated radiochemical yields of 21.24 ± 4.25% and 11.3 ± 3.78%, respectively. The molar activities of 18F-NTRP and 18F-NCRP were 320 ± 40 GBq/μmol and 275 ± 33 GBq/µmol, respectively. In addition, 18F-NTRP and 18F-NCRP exhibited high selectivity and specificity for NTR response. PET-CT imaging in bacteria-infected mouse models with 18F-NTRP or 18F-NCRP showed significant radioactivity uptake in either E. coli- or S. aureus-infected muscles. The uptake for E. coli-infected muscles, 2.4 ± 0.2%ID/g with 18F-NTRP and 4.05 ± 0.49%ID/g with 18F-NCRP, was up to three times greater than that for uninfected control muscles. Furthermore, for both 18F-NTRP and 18F-NCRP, the uptake in bacterial infection was 2.6 times higher than that in sterile inflammation, allowing an effective distinction of infection from inflammation. CONCLUSION 18F-NTRP and 18F-NCRP are worth further investigation to verify their potential clinical application for distinguishing bacterial infection from sterile inflammation via their specific NTR responsiveness.
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Boddeti DK, Kumar V. Evaluation of 68Ga-DOTA-Ubiquicidin (29-41) for imaging Staphylococcus aureus (Staph A) infection and turpentine-induced inflammation in a preclinical setting. World J Nucl Med 2021; 20:266-272. [PMID: 34703395 PMCID: PMC8488884 DOI: 10.4103/wjnm.wjnm_103_20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/09/2020] [Accepted: 09/30/2021] [Indexed: 11/07/2022] Open
Abstract
Synthetic antimicrobial peptide fragment, 99mTc-Ubiquicidin 29–41, is shown to be sensitive and also specific for imaging bacterial infections. We undertook this study to explore the advantage of using a positron emission agent, 68Ga-DOTA-Ubiquicidin 29–41 (68Ga-DOTA-UBI), for detecting Staph-A infection in an animal model, and also evaluated its ability to distinguish a turpentine-induced sterile inflammation in an animal model. Pure Ga-68 was freshly eluted from a 68Ge/68Ga generator (IGG-100). DOTA-UBI (50 μg) was ra diolabeled with pure Ga-68 (500MBq) by incubating the reaction mixture at pH 4.5 for 10 min, 95°C. Rats were infected with Staph-A at the hind leg joint of rats to form bacterial abscess. Sterile inflammation was induced in the right thigh muscle by injecting 200 μl of 100% turpentine oil. Rats were injected intravenously with 10–15 MBq of tracer, and images were acquired at different time intervals with Siemens (Biograph mCT) positron emission tomography computed tomography scanner. The early images at 6 min postinjection clearly indicated mild uptake of the agent corresponding to the infection site, which increased dramatically at 20, 30, and 60 min postinjection. The target to background ratio (T/B) increased significantly over the same time period of study (1.6, 4.2, and 6.1, respectively). There was a mild uptake of 68Ga-DOTA-UBI at the site corresponding to sterile inflammation at 6 min postinjection, which was rapidly washed off as seen at 25 and 45 min images. The images indicated fast clearance of the agent from liver and soft tissues within 6 min. Control rats showed similar biodistribution of activity. The mild uptake of 68Ga-DOTA-UBI at the corresponding Staph-A infection lesion and very fast kinetics of clearance from the blood pool and soft tissues suggested a very high clinical potential for this agent. The absence of uptake of the agent at sterile inflammation site suggests that the agent may be useful in distinguishing infection from inflammation.
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Affiliation(s)
- Dilip Kumar Boddeti
- Department of Nuclear Medicine and PET, Westmead Hospital, Sydney NSW, Australia.,Department of Nuclear Medicine, The Children's Hospital at Westmead, Westmead.,Westmead Clinical School, University of Sydney, Sydney NSW, Australia
| | - Vijay Kumar
- Department of Nuclear Medicine and PET, Westmead Hospital, Sydney NSW, Australia.,Department of Nuclear Medicine, The Children's Hospital at Westmead, Westmead.,Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, Sydney NSW, Australia
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Ankrah AO, Sathekge MM, Dierckx RAJO, Glaudemans AWJM. Radionuclide Imaging of Fungal Infections and Correlation with the Host Defense Response. J Fungi (Basel) 2021; 7:jof7060407. [PMID: 34067410 PMCID: PMC8224611 DOI: 10.3390/jof7060407] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 05/10/2021] [Accepted: 05/21/2021] [Indexed: 12/19/2022] Open
Abstract
The human response to invading fungi includes a series of events that detect, kill, or clear the fungi. If the metabolic host response is unable to eliminate the fungi, an infection ensues. Some of the host response’s metabolic events to fungi can be imaged with molecules labelled with radionuclides. Several important clinical applications have been found with radiolabelled biomolecules of inflammation. 18F-fluorodeoxyglucose is the tracer that has been most widely investigated in the host defence of fungi. This tracer has added value in the early detection of infection, in staging and visualising dissemination of infection, and in monitoring antifungal treatment. Radiolabelled antimicrobial peptides showed promising results, but large prospective studies in fungal infection are lacking. Other tracers have also been used in imaging events of the host response, such as the migration of white blood cells at sites of infection, nutritional immunity in iron metabolism, and radiolabelled monoclonal antibodies. Many tracers are still at the preclinical stage. Some tracers require further studies before translation into clinical use. The application of therapeutic radionuclides offers a very promising clinical application of these tracers in managing drug-resistant fungi.
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Affiliation(s)
- Alfred O. Ankrah
- National Centre for Radiotherapy Oncology and Nuclear Medicine, Korle Bu Teaching Hospital, Accra GA-222 7974, Ghana;
- Department of Nuclear Medicine, University of Pretoria, Steve Biko Academic Hospital, Pretoria 0001, South Africa;
- Medical Imaging Center, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands;
| | - Mike M. Sathekge
- Department of Nuclear Medicine, University of Pretoria, Steve Biko Academic Hospital, Pretoria 0001, South Africa;
| | - Rudi A. J. O. Dierckx
- Medical Imaging Center, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands;
| | - Andor W. J. M. Glaudemans
- Medical Imaging Center, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, The Netherlands;
- Correspondence:
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In Vitro and In Vivo Evaluation of 99mTc-Polymyxin B for Specific Targeting of Gram-Bacteria. Biomolecules 2021; 11:biom11020232. [PMID: 33562877 PMCID: PMC7915610 DOI: 10.3390/biom11020232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 01/31/2021] [Accepted: 02/01/2021] [Indexed: 02/06/2023] Open
Abstract
Background: Infectious diseases are one of the main causes of morbidity and mortality worldwide. Nuclear molecular imaging would be of great help to non-invasively discriminate between septic and sterile inflammation through available radiopharmaceuticals, as none is currently available for clinical practice. Here, we describe the radiolabeling procedure and in vitro and in vivo studies of 99mTc-polymyxin B sulfate (PMB) as a new single photon emission imaging agent for the characterization of infections due to Gram-negative bacteria. Results: Labeling efficiency was 97 ± 2% with an average molar activity of 29.5 ± 0.6 MBq/nmol. The product was highly stable in saline and serum up to 6 h. In vitro binding assay showed significant displaceable binding to Gram-negative bacteria but not to Gram-positive controls. In mice, 99mTc-HYNIC-PMB was mainly taken up by liver and kidneys. Targeting studies confirmed the specificity of 99mTc-HYNIC-PMB obtained in vitro, showing significantly higher T/B ratios for Gram-negative bacteria than Gram-positive controls. Conclusions: In vitro and in vivo results suggest that 99mTc-HYNIC-PMB has a potential for in vivo identification of Gram-negative bacteria in patients with infections of unknown etiology. However, further investigations are needed to deeply understand the mechanism of action and behavior of 99mTc-HYNIC-PMB in other animal models and in humans.
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Precise magnetic resonance imaging-guided sonodynamic therapy for drug-resistant bacterial deep infection. Biomaterials 2020; 264:120386. [PMID: 32979656 DOI: 10.1016/j.biomaterials.2020.120386] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/04/2020] [Accepted: 09/14/2020] [Indexed: 12/13/2022]
Abstract
The precise treatment of drug-resistant deep bacterial infections remains a huge challenge in clinic. Herein, a polymer-peptide-porphyrin conjugate (PPPC), which can be real-time monitored in infectious site, is developed for accurate and deep sonodynamic therapy (SDT) based on "in vivo self-assembly" strategy. The PPPC contains four moieties, i.e., a hyperbranched polymer backbone, a self-assembled peptide linked with an enzyme-cleavable peptide-poly (ethylene glycol) terminal, a bacterial targeting peptide, and a porphyrin sonosensitizer (MnTCPP) segment. Once PPPC nanoparticles reach the infectious area, the protecting PEG layers are removed due to the over-expressed gelatinase, leading to the secondary assembly into large nanoaggregates and resultant enhanced accumulation of sonosensitizer. The nanoaggregates exhibit enhanced interaction with bacterial membrane and decrease the minimum inhibitory concentration (MIC) significantly. Meanwhile, compared with free MnTCPP, the concentration of which can not be accurately quantified, the accumulation amount of MnTCPP in PPPCs at infectious site can be in situ monitored by magnetic resonance imaging (MRI) using T1 combined with T2. When the concentration of PPPC-1 reaches MIC, the drug-resistant bacterial infection area is exposed to ultrasound irradiation, causing the precise and efficient elimination of bacteria. Therefore, the MRI-guided SDT system shows extraordinary tissue penetration depth, drug concentration monitoring, morphology-transformation induced accumulation and improved treatment capacity toward drug-resistant bacteria.
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Chen W, Dilsizian V. Molecular Imaging of Cardiovascular Device Infection: Targeting the Bacteria or the Host–Pathogen Immune Response? J Nucl Med 2020; 61:319-326. [DOI: 10.2967/jnumed.119.228304] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 01/22/2020] [Indexed: 12/14/2022] Open
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Lu X, Chen R, Lv J, Xu W, Chen H, Ma Z, Huang S, Li S, Liu H, Hu J, Nie L. High-resolution bimodal imaging and potent antibiotic/photodynamic synergistic therapy for osteomyelitis with a bacterial inflammation-specific versatile agent. Acta Biomater 2019; 99:363-372. [PMID: 31465882 DOI: 10.1016/j.actbio.2019.08.043] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/26/2019] [Accepted: 08/23/2019] [Indexed: 02/05/2023]
Abstract
Unsatisfactory diagnosis and therapy of osteomyelitis are still common but challenging issues for clinicians. To overcome these problems, a bacterial inflammation-specific multifunctional agent, denoted bovine serum albumin-manganese dioxide-ubiquicidin29-41-indocyanine green (ICG) -gentamicin (BMUIG), was synthesized for combined high-resolution bimodal imaging and antibiotic/photodynamic therapy for osteomyelitis. BMUIG binding affinity and antibacterial ability were assessed by using Staphylococcus aureus (S. aureus). Photoacoustic/magnetic resonance imaging was performed on a mouse model of acute osteomyelitis after intravenous injection of BMUIG. Then, myelitis-bearing mice were treated with antibiotic/photodynamic combination therapy. BMUIG specifically targeted S. aureus in comparison with non-targeted agents. In the osteomyelitis model, the infection area was identified accurately and quickly through ICG-based photoacoustic imaging and Mn2+-based T1 magnetic resonance imaging after injection of BMUIG. Furthermore, the manganese dioxide in BMUIG reacted with the locally produced hydrogen peroxide under acidic inflammatory conditions, continuously generating oxygen for enhanced photodynamic therapy. In combination with low-dose gentamicin, a synergistic antibacterial effect was observed and bone infection was resolved. In summary, a non-invasive accurate diagnosis and effective synergistic therapy for osteomyelitis was successfully developed using a bacterial inflammation-specific versatile agent, which would provide a sound theranostic strategy for common infectious diseases. STATEMENT OF SIGNIFICANCE: Osteomyelitis is one of the most serious consequences in orthopedics. However, its inaccurate diagnosis and low-effective antibiotic treatment are still common but challenging issues for clinicians. To overcome these problems, we uniquely designed a bacterial inflammation-specific multifunctional nanoagent, bovine serum albumin-manganese dioxide-ubiquicidin29-41-indocyanine green-gentamicin (BMUIG), for high-resolution bimodal imaging and antibiotic/photodynamic combined therapy of osteomyelitis. Herein, high-resolution imaging technologies refer to classic magnetic resonance imaging and emerging photoacoustic imaging. Photodynamic therapy is subtly introduced because of its safe and effective killing mechanism, which can synergize the bactericidal effect of antibiotics. As a result, we successfully realize non-invasive accurate diagnosis and effective synergistic therapy for osteomyelitis by virtue of the bacterial inflammation-specific versatile agent, which will serve as a promising candidate for sound theranostics in common infectious diseases.
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Affiliation(s)
- Xiaolin Lu
- Department of Orthopaedics, The First Affiliated Hospital of Shantou University Medical College, Shantou 515041, PR China
| | - Ronghe Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnosis & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, PR China
| | - Jing Lv
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnosis & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, PR China
| | - Weicai Xu
- Department of Orthopaedics, The First Affiliated Hospital of Shantou University Medical College, Shantou 515041, PR China
| | - Hongjiang Chen
- Department of Orthopaedics, The First Affiliated Hospital of Shantou University Medical College, Shantou 515041, PR China
| | - Zebin Ma
- Department of Orthopaedics, The First Affiliated Hospital of Shantou University Medical College, Shantou 515041, PR China
| | - Shanshan Huang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnosis & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, PR China
| | - Shi Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnosis & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, PR China
| | - Heng Liu
- Department of Radiology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, PR China
| | - Jun Hu
- Department of Orthopaedics, The First Affiliated Hospital of Shantou University Medical College, Shantou 515041, PR China.
| | - Liming Nie
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnosis & Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361102, PR China.
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Evaluating the potential of kit-based 68Ga-ubiquicidin formulation in diagnosis of infection. Nucl Med Commun 2019; 40:228-234. [DOI: 10.1097/mnm.0000000000000943] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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12
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Salmanoglu E, Kim S, Thakur ML. Currently Available Radiopharmaceuticals for Imaging Infection and the Holy Grail. Semin Nucl Med 2018; 48:86-99. [PMID: 29452623 PMCID: PMC6487501 DOI: 10.1053/j.semnuclmed.2017.10.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Infection is ubiquitous. However, its management is challenging for both the patients and the health-care providers. Scintigraphic imaging of infection dates back nearly half a century. The advances in our understanding of the pathophysiology of disease at cellular and molecular levels have paved the way to the development of a large number of radiopharmaceuticals for scintigraphic imaging of infection. These include radiolabeling of blood elements such as serum proteins, white blood cells (WBCs), and cytokines, to name a few. Infectious foci have also been imaged using a radiolabeled sugar molecule by taking advantage of increased metabolic activity in the infectious lesions. Literature over the years has well documented that none of the radiopharmaceuticals and associated procedures that facilitate imaging infection are flawless and acceptable without a compromise. As a result, only a few compounds such as 99mTc-hexamethylpropyleneamineoxime, 18F-FDG, the oldest but still considered as a gold standard 111In-oxine, and, yes, even 67Ga-citrate in some countries, have remained in routine clinical practice. Nonetheless, the interest of scientists and physicians to improve the approaches to imaging and to the management of infection is noteworthy. These approaches have paved the way for the development of numerous, innovative radiopharmaceuticals to label autologous WBCs ex vivo or even those that could be injected directly to image infection or inflammation without direct involvement of WBCs. In this review, we briefly describe these agents with their pros and cons and place them together for future reference.
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Affiliation(s)
- Ebru Salmanoglu
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107; Department of Nuclear Medicine, Kahramanmaras Sutcu Imam University Faculty of Medicine, Avsar Kampus, Kahramanmaras 46040, Turkey
| | - Sung Kim
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107
| | - Mathew L Thakur
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107; Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107.
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Production of the recombinant antimicrobial peptide UBI 18-35 in Escherichia coli. Protein Expr Purif 2018; 143:38-44. [DOI: 10.1016/j.pep.2017.10.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 10/18/2017] [Accepted: 10/18/2017] [Indexed: 11/21/2022]
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14
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Huang N, Chen X, Zhu X, Xu M, Liu J. Ruthenium complexes/polypeptide self-assembled nanoparticles for identification of bacterial infection and targeted antibacterial research. Biomaterials 2017; 141:296-313. [DOI: 10.1016/j.biomaterials.2017.07.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 06/23/2017] [Accepted: 07/04/2017] [Indexed: 11/30/2022]
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Staderini M, Megia-Fernandez A, Dhaliwal K, Bradley M. Peptides for optical medical imaging and steps towards therapy. Bioorg Med Chem 2017; 26:2816-2826. [PMID: 29042225 DOI: 10.1016/j.bmc.2017.09.039] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 09/22/2017] [Accepted: 09/29/2017] [Indexed: 12/20/2022]
Abstract
Optical medical imaging is a rapidly growing area of research and development that offers a multitude of healthcare solutions both diagnostically and therapeutically. In this review, some of the most recently described peptide-based optical probes are reviewed with a special emphasis on their in vivo use and potential application in a clinical setting.
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Affiliation(s)
- Matteo Staderini
- School of Chemistry, EaStChem, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Alicia Megia-Fernandez
- School of Chemistry, EaStChem, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Kevin Dhaliwal
- EPSRC IRC Proteus Hub, MRC Centre of Inflammation Research, Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Mark Bradley
- School of Chemistry, EaStChem, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, UK; EPSRC IRC Proteus Hub, MRC Centre of Inflammation Research, Queen's Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, UK.
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16
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Auletta S, Baldoni D, Varani M, Galli F, Hajar IA, Duatti A, Ferro-Flores G, Trampuz A, Signore A. Comparison of 99mTc-UBI 29-41, 99mTc-ciprofloxacin, 99mTc-ciprofloxacin dithiocarbamate and 111In-biotin for targeting experimental Staphylococcus aureus and Escherichia coli foreign-body infections: an ex-vivo study. THE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING : OFFICIAL PUBLICATION OF THE ITALIAN ASSOCIATION OF NUCLEAR MEDICINE (AIMN) [AND] THE INTERNATIONAL ASSOCIATION OF RADIOPHARMACOLOGY (IAR), [AND] SECTION OF THE SOCIETY OF RADIOPHARMACEUTICAL CHEMISTRY AND BIOLOGY 2017; 63:37-47. [PMID: 28849632 DOI: 10.23736/s1824-4785.17.02975-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Diagnosis of implant-associated infection is challenging. Several radiopharmaceuticals have been described but direct comparisons are limited. Here we compared in vitro and in an animal model 99mTc-UBI, 99mTc-ciprofloxacin, 99mTcN-CiproCS2 and 111In-DTPA-biotin for targeting E. coli (ATCC 25922) and S. aureus (ATCC 43335). METHODS Stability controls were performed with the labelled radiopharmaceuticals during 6 hours in saline and serum. The in vitro binding to viable or killed bacteria was evaluated at 37 °C and 4 °C. For in vivo studies, Teflon cages were subcutaneously implanted in mice, followed by percutaneous infection. Biodistribution of i.v. injected radiolabelled radiopharmaceuticals were evaluated during 24 h in cages and dissected tissues. RESULTS Labelling efficiency of all radiopharmaceuticals ranged between 94% and 98%, with high stability both in saline and in human serum. In vitro binding assays displayed a rapid but poor bacterial binding for all tested agents. Similar binding kinetic occurred also with heat-killed and ethanol-killed bacteria. In the tissue cage model, infection was detected at different time points: 99mTc-UBI and 99mTcN-CiproCS2 showed higher infected cage/sterile cage ratio at 24 hours for both E. coli and S. aureus; 99mTc-Ciprofloxacin at 24 hours for both E. coli and at 4 hours for S. aureus; 111In-DTPA-biotin accumulates faster in both E. coli and S. aureus infected cages. CONCLUSIONS 99mTc-UBI, 99mTcN-CiproCS2 showed poor in vitro binding but good in vivo binding to E. coli only. 111In-DTPA-biotin showed poor in vitro binding but good in vivo binding to S. aureus and poor to E. coli. 99mTc-Ciprofloxacin showed poor in vitro binding but good in vivo binding to all tested bacteria. The mechanism of accumulation in infected sites remains to be elucidated.
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Affiliation(s)
- Sveva Auletta
- Unit of Nuclear Medicine, Department of Medical-Surgical Sciences and of Translational Medicine, Faculty of Medicine and Psychology, Sapienza University, Rome, Italy
| | - Daniela Baldoni
- Infectious Diseases Research Laboratory, Department of Biomedicine, University Hospital, Basel, Switzerland
| | - Michela Varani
- Unit of Nuclear Medicine, Department of Medical-Surgical Sciences and of Translational Medicine, Faculty of Medicine and Psychology, Sapienza University, Rome, Italy
| | - Filippo Galli
- Unit of Nuclear Medicine, Department of Medical-Surgical Sciences and of Translational Medicine, Faculty of Medicine and Psychology, Sapienza University, Rome, Italy
| | - Iman A Hajar
- Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, Ferrara, Italy
| | - Adriano Duatti
- Laboratory of Nuclear Medicine, Department of Radiological Sciences, University of Ferrara, Ferrara, Italy
| | - Guillermina Ferro-Flores
- Department of Radioactive Material, National Institute of Nuclear Investigations, Center of Nuclear Applications on Health, Ocoyoacac, Mexico
| | - Andrej Trampuz
- Unit of Septic Surgery, Center for Musculoskeletal Surgery, Charité, University of Medicine, Berlin, Germany
| | - Alberto Signore
- Unit of Nuclear Medicine, Department of Medical-Surgical Sciences and of Translational Medicine, Faculty of Medicine and Psychology, Sapienza University, Rome, Italy -
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Dutta J, Baijnath S, Somboro AM, Nagiah S, Albericio F, de la Torre BG, Marjanovic-Painter B, Zeevaart JR, Sathekge M, Kruger HG, Chuturgoon A, Naicker T, Ebenhan T, Govender T. Synthesis, in vitro evaluation, and 68 Ga-radiolabeling of CDP1 toward PET/CT imaging of bacterial infection. Chem Biol Drug Des 2017; 90:572-579. [PMID: 28328161 DOI: 10.1111/cbdd.12980] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 12/21/2022]
Abstract
Bacterial infections are a major concern in the human health sector due to poor diagnosis and development of multidrug-resistant strains. PET/CT provides a means for the non-invasive detection and localization of the infectious foci; however, the radiotracers available are either cumbersome to prepare or their exact contribution toward the imaging is not yet established. Human antimicrobial peptides are of interest for development as PET radiotracers as they are an integral component of the immune system, non-immunogenic toward the recipient, and show selectivity toward pathogens such as bacteria. Herein we report on the potential of LL37, a human cathelicidin antimicrobial peptide, as a radiotracer for bacterial imaging. Bifunctional chelator 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid was utilized to functionalize the antimicrobial peptide, which in turn was capable of chelating gallium. The synthesized nat Ga-CDP1 showed bacterial selectivity and low affinity toward hepatic cells, which are favorable characteristics for further preclinical application.
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Affiliation(s)
- Jyotibon Dutta
- Catalysis and Peptide Research Unit, School of Health Sciences and School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
| | - Sooraj Baijnath
- Catalysis and Peptide Research Unit, School of Health Sciences and School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
| | - Anou M Somboro
- Catalysis and Peptide Research Unit, School of Health Sciences and School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
| | - Savania Nagiah
- Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu Natal, Durban, South Africa
| | - Fernando Albericio
- Catalysis and Peptide Research Unit, School of Health Sciences and School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa.,School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
| | - Beatriz G de la Torre
- Catalysis and Peptide Research Unit, School of Health Sciences and School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
| | - Biljana Marjanovic-Painter
- The South African Nuclear Energy Corporation (Necsa), Radiochemistry, Pelindaba, Brits, South Africa.,Department of Science and Technology, Preclinical Drug Development Platform, North West University, Potchefstroom, South Africa
| | - Jan Rijn Zeevaart
- The South African Nuclear Energy Corporation (Necsa), Radiochemistry, Pelindaba, Brits, South Africa.,Department of Nuclear Medicine, University of Pretoria, Pretoria, South Africa
| | - Mike Sathekge
- University of Pretoria and Steve Biko Academic Hospital, Pretoria, South Africa
| | - Hendrik G Kruger
- Catalysis and Peptide Research Unit, School of Health Sciences and School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
| | - Anil Chuturgoon
- Discipline of Medical Biochemistry, School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu Natal, Durban, South Africa
| | - Tricia Naicker
- Catalysis and Peptide Research Unit, School of Health Sciences and School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
| | - Thomas Ebenhan
- University of Pretoria and Steve Biko Academic Hospital, Pretoria, South Africa
| | - Thavendran Govender
- Catalysis and Peptide Research Unit, School of Health Sciences and School of Chemistry and Physics, University of KwaZulu-Natal, Durban, South Africa
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18
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Kniess T, Laube M, Wüst F, Pietzsch J. Technetium-99m based small molecule radiopharmaceuticals and radiotracers targeting inflammation and infection. Dalton Trans 2017; 46:14435-14451. [DOI: 10.1039/c7dt01735a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
99mTc-labeled antibiotics, antifungal drugs, antimicrobial peptides and COX-2 inhibitors are comprehensively reviewed.
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Affiliation(s)
- Torsten Kniess
- Helmholtz-Zentrum Dresden-Rossendorf
- Institute of Radiopharmaceutical Cancer Research
- 01328 Dresden
- Germany
| | - Markus Laube
- Helmholtz-Zentrum Dresden-Rossendorf
- Institute of Radiopharmaceutical Cancer Research
- 01328 Dresden
- Germany
| | - Frank Wüst
- University of Alberta
- Department of Oncology
- 11560 University Avenue
- Edmonton
- Canada
| | - Jens Pietzsch
- Helmholtz-Zentrum Dresden-Rossendorf
- Institute of Radiopharmaceutical Cancer Research
- 01328 Dresden
- Germany
- Technische Universität Dresden
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Abstract
The rise in multidrug resistant (MDR) bacteria has become a global crisis. Rapid and accurate diagnosis of infection will facilitate antibiotic stewardship and preserve our ability to treat and cure patients from bacterial infection. Direct in situ imaging of bacteria offers the prospect of accurately diagnosing disease and monitoring patient outcomes and response to treatment in real-time. There have been many recent advances in the field of optical imaging of infection; namely in specific probe and fluorophore design. This combined with the advances in imaging device technology render direct optical imaging of infection a feasible approach for accurate diagnosis in the clinic. Despite this, there are currently no licensed molecular probes for clinical optical imaging of infection. Here we report some of the most promising and interesting probes and approaches under development for this purpose, which have been evaluated in in vivo models within the laboratory setting.
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20
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Vilche M, Reyes AL, Vasilskis E, Oliver P, Balter H, Engler H. ⁶⁸Ga-NOTA-UBI-29-41 as a PET Tracer for Detection of Bacterial Infection. J Nucl Med 2016; 57:622-7. [PMID: 26769861 DOI: 10.2967/jnumed.115.161265] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 12/07/2015] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The cationic peptide (68)Ga-NOTA-UBI-29-41 was synthesized and characterized. Biodistribution and PET/CT examinations were performed for evaluation of its biologic behavior. Differentiation of infection from sterile inflammation was investigated using microbiology methods at the sites of bacterial infections. METHODS Labeling of UBI-29-41 conjugated with NOTA with (68)Ga was optimized at 20°C-100°C and pH 3.5-5.5. Radiochemical purity, stability up to 260 min, and binding to serum proteins were determined. In vitro binding to Staphylococcus aureus was evaluated from 9.14 × 10(7) to 1.17 × 10(10) cfu/mL. Of 3 groups of Mus musculus Swiss male mice, the first was inoculated intramuscularly with 1.2 × 10(8) cfu of S. aureus to provoke infection, and the second, with 1.2 × 10(8) cfu of heat shock-treated S. aureus to generate sterile inflammation. The third mouse was not treated and served as a control. After 24 h, (68)Ga-NOTA-UBI-29-41 was administrated intravenously, and biodistribution was performed at 30, 60, and 120 min. PET/CT dynamic studies (120 min) were acquired. Sinograms were reconstructed using 3D maximum-likelihood expectation maximization and analyzed with software. Infected or inflamed muscles were dissected, homogenized, and cultured in tryptic soy agar medium. Recovered S. aureus was calculated as cfu/g. RESULTS (68)Ga-NOTA-UBI-29-41 showed high renal excretion (83.2% ± 7.3%) of injected dose and rapid blood clearance. More than 95% was bound in vitro to 5 × 10(9) cfu/mL. A significantly higher (P< 0.05) accumulation of (68)Ga-NOTA-UBI-29-41 was observed at sites of S. aureus inoculation in infected mice (ratio of target to nontarget, 5.0 at 60 min and 4.1 at 120 min) compared with animals with inflammation (ratio of target to nontarget, 1.6 at 60 min and 1.2 at 120 min). CONCLUSION The difference in uptake of (68)Ga-NOTA-UBI-29-41 in the infected muscles compared with the inflamed muscles was clearly observed in the PET/CT images and positively correlated with the degree of infection.
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Affiliation(s)
- Mónica Vilche
- Uruguayan Centre of Molecular Imaging, Montevideo, Uruguay
| | | | | | | | - Henia Balter
- Uruguayan Centre of Molecular Imaging, Montevideo, Uruguay
| | - Henry Engler
- Uruguayan Centre of Molecular Imaging, Montevideo, Uruguay
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21
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Akram AR, Avlonitis N, Lilienkampf A, Perez-Lopez AM, McDonald N, Chankeshwara SV, Scholefield E, Haslett C, Bradley M, Dhaliwal K. A labelled-ubiquicidin antimicrobial peptide for immediate in situ optical detection of live bacteria in human alveolar lung tissue. Chem Sci 2015; 6:6971-6979. [PMID: 29861935 PMCID: PMC5947527 DOI: 10.1039/c5sc00960j] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 06/26/2015] [Indexed: 02/02/2023] Open
Abstract
The in situ immediate detection of the presence of bacteria in the distal human lung is of significant clinical utility. Herein we describe the development and optimization of a bacterial binding fragment (UBI29-41) of the antimicrobial peptide, ubiquicidin (UBI), conjugated to an environmentally sensitive fluorophore to enable rapid live bacterial imaging within human lung tissue. UBI29-41 was modified for stability in the presence of human lung bronchoalveolar lavage fluid, for affinity to bacterial membranes and functionality in human lung tissue. The optimized cyclic structure yields an optical molecular Smartprobe for bacterial detection in human lung tissue.
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Affiliation(s)
- Ahsan R Akram
- Pulmonary Optical Molecular Imaging Group , MRC Centre for Inflammation Research , Queen's Medical Research Institute , 47 Little France Crescent , Edinburgh , EH16 4TJ , UK .
| | - Nicolaos Avlonitis
- EaStCHEM , The University of Edinburgh School of Chemistry , Joseph Black Building, West Mains Road , Edinburgh EH9 3FJ , UK .
| | - Annamaria Lilienkampf
- EaStCHEM , The University of Edinburgh School of Chemistry , Joseph Black Building, West Mains Road , Edinburgh EH9 3FJ , UK .
| | - Ana M Perez-Lopez
- EaStCHEM , The University of Edinburgh School of Chemistry , Joseph Black Building, West Mains Road , Edinburgh EH9 3FJ , UK .
| | - Neil McDonald
- Pulmonary Optical Molecular Imaging Group , MRC Centre for Inflammation Research , Queen's Medical Research Institute , 47 Little France Crescent , Edinburgh , EH16 4TJ , UK .
| | - Sunay V Chankeshwara
- EaStCHEM , The University of Edinburgh School of Chemistry , Joseph Black Building, West Mains Road , Edinburgh EH9 3FJ , UK .
| | - Emma Scholefield
- Pulmonary Optical Molecular Imaging Group , MRC Centre for Inflammation Research , Queen's Medical Research Institute , 47 Little France Crescent , Edinburgh , EH16 4TJ , UK .
| | - Christopher Haslett
- Pulmonary Optical Molecular Imaging Group , MRC Centre for Inflammation Research , Queen's Medical Research Institute , 47 Little France Crescent , Edinburgh , EH16 4TJ , UK .
| | - Mark Bradley
- EaStCHEM , The University of Edinburgh School of Chemistry , Joseph Black Building, West Mains Road , Edinburgh EH9 3FJ , UK .
| | - Kevin Dhaliwal
- Pulmonary Optical Molecular Imaging Group , MRC Centre for Inflammation Research , Queen's Medical Research Institute , 47 Little France Crescent , Edinburgh , EH16 4TJ , UK .
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van Oosten M, Hahn M, Crane LMA, Pleijhuis RG, Francis KP, van Dijl JM, van Dam GM. Targeted imaging of bacterial infections: advances, hurdles and hopes. FEMS Microbiol Rev 2015; 39:892-916. [PMID: 26109599 DOI: 10.1093/femsre/fuv029] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/26/2015] [Indexed: 02/06/2023] Open
Abstract
Bacterial infections represent an increasing problem in modern health care, in particular due to ageing populations and accumulating bacterial resistance to antibiotics. Diagnosis is rarely straightforward and consequently treatment is often delayed or indefinite. Therefore, novel tools that can be clinically implemented are urgently needed to accurately and swiftly diagnose infections. Especially, the direct imaging of infections is an attractive option. The challenge of specifically imaging bacterial infections in vivo can be met by targeting bacteria with an imaging agent. Here we review the current status of targeted imaging of bacterial infections, and we discuss advantages and disadvantages of the different approaches. Indeed, significant progress has been made in this field and the clinical implementation of targeted imaging of bacterial infections seems highly feasible. This was recently highlighted by the use of so-called smart activatable probes and a fluorescently labelled derivative of the antibiotic vancomycin. A major challenge remains the selection of the best imaging probes, and we therefore present a set of target selection criteria for clinical implementation of targeted bacterial imaging. Altogether, we conclude that the spectrum of potential applications for targeted bacterial imaging is enormous, ranging from fundamental research on infectious diseases to diagnostic and therapeutic applications.
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Affiliation(s)
- Marleen van Oosten
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO Box 30001, 9700 RB Groningen, the Netherlands Department of Surgery, Division of Surgical Oncology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO Box 30001, 9700 RB Groningen, the Netherlands
| | - Markus Hahn
- Department of Surgery, Division of Surgical Oncology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO Box 30001, 9700 RB Groningen, the Netherlands
| | - Lucia M A Crane
- Department of Surgery, Division of Surgical Oncology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO Box 30001, 9700 RB Groningen, the Netherlands
| | - Rick G Pleijhuis
- Department of Surgery, Division of Surgical Oncology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO Box 30001, 9700 RB Groningen, the Netherlands
| | | | - Jan Maarten van Dijl
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO Box 30001, 9700 RB Groningen, the Netherlands
| | - Gooitzen M van Dam
- Department of Surgery, Division of Surgical Oncology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO Box 30001, 9700 RB Groningen, the Netherlands
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Chen H, Zhang M, Li B, Chen D, Dong X, Wang Y, Gu Y. Versatile antimicrobial peptide-based ZnO quantum dots for in vivo bacteria diagnosis and treatment with high specificity. Biomaterials 2015; 53:532-44. [DOI: 10.1016/j.biomaterials.2015.02.105] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 02/21/2015] [Accepted: 02/24/2015] [Indexed: 01/09/2023]
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Welling MM, Bunschoten A, Kuil J, Nelissen RGHH, Beekman FJ, Buckle T, van Leeuwen FWB. Development of a Hybrid Tracer for SPECT and Optical Imaging of Bacterial Infections. Bioconjug Chem 2015; 26:839-49. [PMID: 25853214 DOI: 10.1021/acs.bioconjchem.5b00062] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In trauma and orthopedic surgery, infection of implants has a major impact on the outcome for patients. Infections may develop either during the initial implantation or during the lifetime of an implant. Both infections, as well as aseptic loosening of the implant, are reasons for revision of the implants. Therefore, discrimination between aseptic-mechanical-loosening and septic-bacterial-loosening of implants is critical during selection of a patient-tailored treatment policy. Specific detection and visualization of infections is a challenge because it is difficult to discriminate infections from inflammation. An imaging tracer that facilitates bacterial identification in a pre- and intraoperative setting may aid the workup for patients suspicious of bacterial infections. In this study we evaluated an antimicrobial peptide conjugated to a hybrid label, which contains both a radioisotope and a fluorescent dye. After synthesis of DTPA-Cy5-UBI29-41 and-when necessary-radiolabeling with (111)In (yield 96.3 ± 2.7%), in vitro binding to various bacterial strains was evaluated using radioactivity counting and confocal fluorescence microscopy. Intramuscular bacterial infections (S. aureus or K. pneumoniae) were also visualized in vivo using a combined nuclear and fluorescence imaging system. The indium-111 was chosen as label as it has a well-defined coordination chemistry, and in pilot studies labeling DTPA-Cy5-UBI29-41 with technetium-99m, we encountered damage to the Cy5 dye after the reduction with SnCl2. As a reference, we used the validated tracer (99m)Tc-UBI29-41. Fast renal excretion of (111)In-DTPA-Cy5-UBI29-41 was observed. Target to nontarget (T/NT) ratios were highest at 2 h post injection: radioactivity counting yielded T/NT ratios of 2.82 ± 0.32 for S. aureus and 2.37 ± 0.05 for K. pneumoniae. Comparable T/NT ratios with fluorescence imaging of 2.38 ± 0.09 for S. aureus and 3.55 ± 0.31 for K. pneumoniae were calculated. Ex vivo confocal microscopy of excised infected tissues showed specific binding of the tracer to bacteria. Using a combination of nuclear and fluorescence imaging techniques, the hybrid antimicrobial peptide conjugate DTPA-Cy5-UBI29-41 was shown to specifically accumulate in bacterial infections. This hybrid tracer may facilitate integration of noninvasive identification of infections and their extent as well as real-time fluorescence guidance during surgical resection of infected areas.
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Affiliation(s)
| | | | | | | | - Freek J Beekman
- §Delft University of Technology, 2628 CD Delft, The Netherlands.,∥MILabs, 3584 CX Utrecht, The Netherlands
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Rice DR, Plaunt AJ, Turkyilmaz S, Smith M, Wang Y, Rusckowski M, Smith BD. Evaluation of [¹¹¹In]-labeled zinc-dipicolylamine tracers for SPECT imaging of bacterial infection. Mol Imaging Biol 2015; 17:204-13. [PMID: 25115869 PMCID: PMC4515950 DOI: 10.1007/s11307-014-0758-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE This study prepared three structurally related zinc-dipicolylamine (ZnDPA) tracers with [(111)In] labels and conducted biodistribution and single-photon emission computed tomography/computed tomography (SPECT/CT) imaging studies of a mouse leg infection model. PROCEDURES Two monovalent tracers, ZnDPA-[(111)In]DTPA and ZnDPA-[(111)In]DOTA, each with a single zinc-dipicolylamine targeting unit, and a divalent tracer, Bis(ZnDPA)-[(111)In]DTPA, with two zinc-dipicolylamine units were prepared. Organ biodistribution and SPECT and CT imaging studies were performed on living mice with a leg infection created by injection of clinically relevant Gram positive Streptococcus pyogenes. Fluorescent and luminescent Eu(3+)-labeled versions of these tracers were also prepared and used to measure relative affinity for the exterior membrane surface of bacterial cells and mimics of healthy mammalian cells. RESULTS All three (111)In-labeled radiotracers were prepared with a radiopurity of >90 %. The biodistribution studies showed that the two monovalent tracers were cleared from the body through the liver and kidney, with retained percentage injected dose for all organs of <8 % at 20 h and infected leg target to non-target ratio (T/NT) ratio of ≤3.0. Clearance of the divalent tracer from the bloodstream was slower and primarily through the liver, with a retained percentage injected dose for all organs <37 % at 20 h and T/NT ratio rising to 6.2 after 20 h. The SPECT/CT imaging indicated the same large difference in tracer pharmacokinetics and higher accumulation of the divalent tracer at the site of infection. CONCLUSIONS All three [(111)In]-ZnDPA tracers selectively targeted the site of a clinically relevant mouse infection model that could not be discerned by visual external inspection of the living animal. The highest target selectivity, observed with a divalent tracer equipped with two zinc-dipicolylamine targeting units, compares quite favorably with the imaging selectivities previously reported for other nuclear tracers that target bacterial cell surfaces. The tracer pharmacokinetics depended heavily on tracer molecular structure suggesting that it may be possible to rapidly fine tune the structural properties for optimized in vivo imaging performance and clinical translation.
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Affiliation(s)
- Douglas R Rice
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
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Rotman M, Welling MM, Bunschoten A, de Backer ME, Rip J, Nabuurs RJ, Gaillard PJ, van Buchem MA, van der Maarel SM, van der Weerd L. Enhanced glutathione PEGylated liposomal brain delivery of an anti-amyloid single domain antibody fragment in a mouse model for Alzheimer's disease. J Control Release 2015; 203:40-50. [PMID: 25668771 DOI: 10.1016/j.jconrel.2015.02.012] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 02/03/2015] [Accepted: 02/05/2015] [Indexed: 01/08/2023]
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27
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Synthesis, 68Ga-radiolabeling, and preliminary in vivo assessment of a depsipeptide-derived compound as a potential PET/CT infection imaging agent. BIOMED RESEARCH INTERNATIONAL 2015; 2015:284354. [PMID: 25699267 PMCID: PMC4324493 DOI: 10.1155/2015/284354] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 07/28/2014] [Accepted: 08/05/2014] [Indexed: 11/21/2022]
Abstract
Noninvasive imaging is a powerful tool for early diagnosis and monitoring of various disease processes, such as infections. An alarming shortage of infection-selective radiopharmaceuticals exists for overcoming the diagnostic limitations with unspecific tracers such as 67/68Ga-citrate or 18F-FDG. We report here TBIA101, an antimicrobial peptide derivative that was conjugated to DOTA and radiolabeled with 68Ga for a subsequent in vitro assessment and in vivo infection imaging using Escherichia coli-bearing mice by targeting bacterial lipopolysaccharides with PET/CT. Following DOTA-conjugation, the compound was verified for its cytotoxic and bacterial binding behaviour and compound stability, followed by 68Gallium-radiolabeling. µPET/CT using 68Ga-DOTA-TBIA101 was employed to detect muscular E. coli-infection in BALB/c mice, as warranted by the in vitro results. 68Ga-DOTA-TBIA101-PET detected E. coli-infected muscle tissue (SUV = 1.3–2.4) > noninfected thighs (P = 0.322) > forearm muscles (P = 0.092) > background (P = 0.021) in the same animal. Normalization of the infected thigh muscle to reference tissue showed a ratio of 3.0 ± 0.8 and a ratio of 2.3 ± 0.6 compared to the identical healthy tissue. The majority of the activity was cleared by renal excretion. The latter findings warrant further preclinical imaging studies of greater depth, as the DOTA-conjugation did not compromise the TBIA101's capacity as targeting vector.
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Kahrom M, Mehrabi Bahar M, Jangjoo A, Erfani M, Sadeghi R, Zakavi SR. Poor sensitivity of 99mTc-labeled ubiquicidin scintigraphy in diagnosis of acute appendicitis. Eur Surg 2014. [DOI: 10.1007/s10353-014-0278-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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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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Ebenhan T, Chadwick N, Sathekge MM, Govender P, Govender T, Kruger HG, Marjanovic-Painter B, Zeevaart JR. Peptide synthesis, characterization and 68Ga-radiolabeling of NOTA-conjugated ubiquicidin fragments for prospective infection imaging with PET/CT. Nucl Med Biol 2014; 41:390-400. [DOI: 10.1016/j.nucmedbio.2014.02.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 01/05/2014] [Accepted: 02/06/2014] [Indexed: 10/25/2022]
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Ebenhan T, Zeevaart JR, Venter JD, Govender T, Kruger GH, Jarvis NV, Sathekge MM. Preclinical evaluation of 68Ga-labeled 1,4,7-triazacyclononane-1,4,7-triacetic acid-ubiquicidin as a radioligand for PET infection imaging. J Nucl Med 2014; 55:308-14. [PMID: 24434293 DOI: 10.2967/jnumed.113.128397] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
UNLABELLED Antimicrobial peptides such as ubiquicidin (UBI) are believed to differentiate between mammalian and bacterial or fungal cells. (99m)Tc-UBI29-41 was previously tested for detecting infection in humans using SPECT. For the present study, the UBI fragment UBI29-41 (TGRAKRRMQYNRR) was conjugated to 1,4,7-triazacyclononane-triacetic acid (NOTA), radiolabeled with (68)Ga, and investigated in a rabbit infection model. METHODS (68)Ga was obtained from a 1.85-GBq (68)Ge/(68)Ga generator. New Zealand White rabbits were anesthetized with ketamine/medetomidine before tracer administration and placed in a clinical PET/CT scanner. (68)Ga-1,4,7-triazacyclononane-1,4,7-triacetic-acid-ubiquicidin29-41 ((68)Ga-NOTA-UBI29-41) was formulated in saline solution, and 101 ± 41 MBq were administered intravenously. The tracer distribution was studied by PET/CT imaging in animals (a) that were healthy, (b) bearing muscular Staphylococcus aureus infections and turpentine oil-induced muscular inflammations, and (c) bearing ovalbumin-induced lung inflammations. Static PET/CT imaging was performed at different time intervals up to 120 min after injection. For calculation of target-to-nontarget ratios, standardized uptake values were normalized against healthy thigh muscle, representing nontargeted tissue. RESULTS PET/CT images of healthy animals showed predominant distribution in the kidneys, liver, and bladder; heart and spleen showed moderate, declining uptake, only. The biologic half-life in blood was 29 min. Urinary accumulation of (68)Ga-NOTA-UBI29-41 peaked at 3.8 ± 0.91 percentage injected dose per gram (%ID) at 120 min, and 88 ± 5.2 %ID was recovered in total urine. (68)Ga-NOTA-UBI29-41 imaging in (b) selectively visualized the muscular infection site and was differentiated from sterile inflammatory processes. Standardized uptake value ratios for muscles (infected/inflamed) were 2.9 ± 0.93, 2.9 ± 0.50, 3.5 ± 0.86, and 3.8 ± 0.90 at 5, 30, 60, and 90 min after injection, respectively. Rabbit lungs with asthma showed insignificant uptake. CONCLUSION (68)Ga-NOTA-UBI29-41 was strongly localized in bacteria-infected areas and minimally detected in a sterile inflammation area in rabbit muscles. The findings propose this compound to be an excellent first-line PET/CT tracer to allow the distinguishing of infection from inflammation.
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Affiliation(s)
- Thomas Ebenhan
- Department of Nuclear Medicine, University of Pretoria and Steve Biko Academic Hospital, Pretoria, South Africa
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Bunschoten A, Welling MM, Termaat MF, Sathekge M, van Leeuwen FWB. Development and Prospects of Dedicated Tracers for the Molecular Imaging of Bacterial Infections. Bioconjug Chem 2013; 24:1971-89. [PMID: 24200346 DOI: 10.1021/bc4003037] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- A. Bunschoten
- Department
of Radiology, Interventional Molecular Imaging Laboratory, Leiden University Medical Center, Leiden, The Netherlands
| | - M. M. Welling
- Department
of Radiology, Interventional Molecular Imaging Laboratory, Leiden University Medical Center, Leiden, The Netherlands
| | - M. F. Termaat
- Department
of Trauma Surgery, Leiden University Medical Center, Leiden, The Netherlands
| | - M. Sathekge
- Department of Nuclear Medicine, University of Pretoria & Steve Biko Academic Hospital, Pretoria, South Africa
| | - F. W. B. van Leeuwen
- Department
of Radiology, Interventional Molecular Imaging Laboratory, Leiden University Medical Center, Leiden, The Netherlands
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Functional Imaging in Diagnostic of Orthopedic Implant-Associated Infections. Diagnostics (Basel) 2013; 3:356-71. [PMID: 26824928 PMCID: PMC4665528 DOI: 10.3390/diagnostics3040356] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 09/10/2013] [Accepted: 09/22/2013] [Indexed: 12/11/2022] Open
Abstract
Surgeries’ sterile conditions and perioperative antibiotic therapies decrease implant associated infections rates significantly. However, up to 10% of orthopedic devices still fail due to infections. An implant infection generates a high socio-economic burden. An early diagnosis of an infection would significantly improve patients’ outcomes. There are numerous clinical tests to diagnose infections. The “Gold Standard” is a microbiological culture, which requires an invasive sampling and lasts up to several weeks. None of the existing tests in clinics alone is sufficient for a conclusive diagnosis of an infection. Meanwhile, there are functional imaging modalities, which hold the promise of a non-invasive, quick, and specific infection diagnostic. This review focuses on orthopedic implant-associated infections, their pathogenicity, diagnosis and functional imaging.
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Kumar V, Boddeti DK. (68)Ga-radiopharmaceuticals for PET imaging of infection and inflammation. Recent Results Cancer Res 2013; 194:189-219. [PMID: 22918761 DOI: 10.1007/978-3-642-27994-2_11] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Infection imaging has been challenging over the past four decades, which provided an excellent playing field for researchers working in this area, and till date the quest continues to find an ideal imaging agent. Labelled leukocytes were first developed in the 1970s for imaging infection lesions such as osteomyelitis, cellulitis, diabetic foot, Crohn's disease, inflammatory bowel disease, fever of unknown origin, etc. Subsequently labelled antibiotics such as (99m)Tc-labelled ciprofloxacin have emerged for directly identifying live bacterial infections. From the early 1970s through the mid-1980s,( 67)Ga-Citrate was the prime radionuclide for imaging of inflammation and infection of musculoskeletal origin. Although (68)Ga-PET was described in 1960s for tumour imaging, recent reports described (68)Ga-Citrate and (68)Ga-transferrin as possible agents for PET-imaging of infection due to successful application of (67)Ga-Citrate SPECT in the past, despite its limitations. It is important to establish a faster imaging method for (68)Ga, as its half-life is 68 min compared to 78.3 hrs for (67)Ga. Preparation of (68)Ga-Citrate and (68)Ga-transferrin is described, with very high yield and high radiochemical purity (RCP), which is ideally suited for routine clinical studies. Biodistribution of (68)Ga-Citrate-PET images were characterised with high blood pool, high liver and bone (growth plate) uptake with low soft-tissue activity. (68)Ga-Citrate or (68)Ga-transferrin was able to detect infected lesions in rats within 5-10 min post injection but a focal intense uptake at the lesion (SUV(max)) was visualized only at 30 min, which increased for up to 6 hrs post injection with concomitant decrease in the cardiac blood pool activity. The liver and bowel activity decreased after 90 min then stabilised. In the patient studies, infection lesions were detected within 30 min post injection of (68)Ga-Citrate. Cardiac blood pool and liver activities decreased during the period of study. Interestingly, there was persistent high vascular activity in the thigh region. One of the major limitations of (67)Ga-Citrate SPECT is the delayed post injection waiting time of 48 hrs, in contrast to 60 min post injection waiting with (68)Ga-Citrate. The distinct difference in imaging time is intriguing, although there is no chemical difference between (67)Ga-Citrate and (68)Ga-Citrate, except for the radiolabel. No literature is available on early imaging times using (67)Ga-SPECT. When compared (68)Ga/(67)Ga-Citrate images at 60 min post injection in normal rats, (68)Ga-PET showed better images with low background activity than (67)Ga-SPECT agent. This may be due to short half-life of (68)Ga (68 min), as it would have decayed one half-life at 60 min post-imaging time, compared to the SPECT agent ((67)Ga), which would require 76 hrs to undergo one half-life. Therefore, the visual difference in background can be attributed to the difference in the half-lives of these two agents. Similarly, uptake of (68)Ga by liver, cardiac blood pool activity is much lower than (67)Ga at 60 min post injection period, may be attributed to the faster decay of (68)Ga than (67)Ga. High background activity of (68)Ga-Citrate in the thorax and upper abdomen at 60 min post-injection may interfere with detecting lesions in these regions; therefore, (68)Ga-PET is more suitable for imaging lesions in the lower abdomen and the extremities. The short half-life of (68)Ga (68 min) may be advantageous from low dosimetry to the patients, but disadvantageous for longer periods of study. Since (68)Ga-Citrate was capable of detecting infection within 60 min, the need for imaging for longer periods may not be warranted. The functional imaging was not limited to diagnosing infection but it could be extended to surgical planning and antibiotic therapy monitoring of osteomyelitis and in distinguishing prosthetic infection from loosening of prosthesis. (18)F-FDG is sensitive but has the limitation of giving false positive results in patients with bone prosthesis, even if there is no infection or mobilisation. But the available literature clearly indicated (68)Ga-Citrate was positive only in cases of infection. In summary, preliminary reports suggest (68)Ga-Citrate PET/CT is useful in the diagnosis of suspected bone infections with reliable sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy. Preliminary reports with (68)Ga-Transferrin showed it is capable of detecting both Gram-positive Staphylococcus aureus (Staph A) and Gram-negative Proteus mirobilis. This is an incidental finding but gives an insight into the potential of this agent to detect more than one bacterial infection.
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Affiliation(s)
- Vijay Kumar
- Department of Nuclear Medicine, The Children's Hospital at Westmead, Westmead, Australia.
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Antimicrobial peptides as infection imaging agents: better than radiolabeled antibiotics. INTERNATIONAL JOURNAL OF PEPTIDES 2012; 2012:965238. [PMID: 22675369 PMCID: PMC3362861 DOI: 10.1155/2012/965238] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 02/09/2012] [Accepted: 03/11/2012] [Indexed: 11/17/2022]
Abstract
Nuclear medicine imaging techniques offer whole body imaging for localization of number and site of infective foci inspite of limitation of spatial resolution. The innate human immune system contains a large member of important elements including antimicrobial peptides to combat any form of infection. However, development of antibiotics against bacteria progressed rapidly and gained popularity over antimicrobial peptides but even powerful antimicrobials failed to reduce morbidity and mortality due to emergence of mutant strains of bacteria resulting in antimicrobial resistance. Differentiation between infection and inflammation using radiolabeled compounds with nuclear medicine techniques has always been a dilemma which is still to be resolved. Starting from nonspecific tracers to specific radiolabeled tracers, the question is still unanswered. Specific radiolabeled tracers included antibiotics and antimicrobial peptides which bind directly to the bacteria for efficient localization with advanced nuclear medicine equipments. However, there are merits and demerits attributed to each. In the current paper, radiolabeled antibiotics and radiolabeled peptides for infection localization have been discussed starting with the background of primitive nonspecific tracers. Radiolabeled antimicrobial peptides have certain merits compared with labeled antibiotics which make them superior agents for localization of infective focus.
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Lupetti A, de Boer MGJ, Erba P, Campa M, Nibbering PH. Radiotracers for fungal infection imaging. Med Mycol 2011; 49 Suppl 1:S62-9. [DOI: 10.3109/13693786.2010.508188] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Specificity of 99mTc-UBI for detecting infection foci in patients with fever in study. Nucl Med Commun 2010; 31:889-95. [DOI: 10.1097/mnm.0b013e32833d96d1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Essouissi I, Ghali W, Saied NM, Saidi M. Synthesis and evaluation of 99mTc-N-sulfanilamide ferrocene carboxamide as bacterial infections detector. Nucl Med Biol 2010; 37:821-9. [DOI: 10.1016/j.nucmedbio.2010.04.139] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 04/06/2010] [Accepted: 04/16/2010] [Indexed: 11/29/2022]
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Performance of a 99mTc-labelled 1-thio-β-D-glucose 2,3,4,6-tetra-acetate analogue in the detection of infections and tumours in mice: a comparison with [18F]FDG. Nucl Med Commun 2010; 31:239-48. [PMID: 20032803 DOI: 10.1097/mnm.0b013e32833501e4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Meléndez-Alafort L, Nadali A, Pasut G, Zangoni E, De Caro R, Cariolato L, Giron MC, Castagliuolo I, Veronese FM, Mazzi U. Detection of sites of infection in mice using 99mTc-labeled PN(2)S-PEG conjugated to UBI and 99mTc-UBI: a comparative biodistribution study. Nucl Med Biol 2009; 36:57-64. [PMID: 19181269 DOI: 10.1016/j.nucmedbio.2008.10.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 10/15/2008] [Accepted: 10/25/2008] [Indexed: 11/29/2022]
Abstract
UNLABELLED The antimicrobial peptide ubiquicidin (UBI) directly labeled with technetium-99m ((99m)Tc) has recently been shown to be specifically taken up at sites of infection; however, its chemical structure is not well defined. To address this problem, the aim of the present study was to label UBI using poly(ethyleneglycol)-N-(N-(3-diphenylphosphinopropionyl)glycyl)-S-tritylcysteine ligand (PEG-PN(2)S) in order to compare its ability to detect infection sites with that of (99m)Tc-UBI. METHODS The PN(2)S-PEG-UBI conjugate was prepared and labeled with (99m)Tc, and its radiochemical purity was subsequently assessed. The stability of the conjugate to cysteine challenge and dilution with both saline solution and phosphate buffer was determined and serum stability and protein binding were also assessed. In vivo studies were carried out in healthy mice to study the biodistribution of (99m)Tc-PN(2)S-PEG-UBI and its precursor (99m)Tc-PN(2)S-PEG and in infected mice to compare the uptakes of (99m)Tc-UBI and (99m)Tc-PN(2)S-PEG-UBI at the site of infection using scintigraphic imaging and ex vivo tissue counting. RESULTS (99m)Tc-PN(2)S-PEG-UBI was obtained with high radiochemical purity (98+/-1%) and high stability. The amphiphilic nature of the conjugate leads to a tendency to form micellar aggregates that explain the high protein binding values obtained. Biodistribution studies in mice showed low renal clearance followed by a predominant reticuloendothelial system clearance that limits its application in the abdominal area. Statistical analysis revealed no significant difference between (99m)Tc-UBI and (99m)Tc-PN(2)S-PEG-UBI uptake in infected mouse thigh, and the site of infection was clearly visualized using scintigraphic imaging. CONCLUSIONS (99m)Tc-PN(2)S-PEG-UBI proved to be as effective as (99m)Tc-UBI in detecting sites of infection; however, the well-defined chemical structure of (99m)Tc-PN(2)S-PEG-UBI makes it a better candidate for clinical imaging of infection.
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Gandomkar M, Najafi R, Shafiei M, Mazidi M, Goudarzi M, Mirfallah SH, Ebrahimi F, Heydarpor HR, Abdie N. Clinical evaluation of antimicrobial peptide [(99m)Tc/Tricine/HYNIC(0)]ubiquicidin 29-41 as a human-specific infection imaging agent. Nucl Med Biol 2009; 36:199-205. [PMID: 19217532 DOI: 10.1016/j.nucmedbio.2008.11.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 10/27/2008] [Accepted: 11/11/2008] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Ubiquicidin (UBI) 29-41 is a cationic synthetic antimicrobial peptide fragment that binds preferentially with the anionic microbial cell membrane at the site of infection. This study was conducted to evaluate the potentiality of [(99m)Tc/Tricine/HYNIC(0)]UBI 29-41 prepared from lyophilized kits as an infection imaging agent in humans. METHODS Seven patients (5 males and 2 females; mean age=55 years; age range=35-75 years) with suspected bone or soft-tissue infections participated in this study. [(99m)Tc/Tricine/HYNIC]UBI 29-41, corresponding to activity in the range 555-740 MBq added to 40 mug of peptide obtained from instant freeze-dried kit formulations with radiochemical purities >95%, was injected intravenously. A 45-min dynamic study was followed by spot views of the suspected region of infection (target) and a corresponding normal area (nontarget). Whole-body anterior and posterior images were also acquired at 30, 60 and 120 min after injection. True- or false-positive or true- or false-negative images were interpreted upon bacterial culture, radiography, clinical tests and bone scanning. RESULTS The biodistribution of [(99m)Tc/Tricine/HYNIC]UBI 29-41 in patients showed rapid accumulation of activity in the kidneys in the first 30 min after injection that gradually declined and accumulated in the urinary bladder. There were positive findings in five studies and negative findings in two. Findings were subsequently confirmed to be true positive or negative. Images showed minimal accumulation in nontarget tissues, with an average target/nontarget ratio of 2.10+/-0.33 in positive lesions at 30 min. CONCLUSION Given its favorable clinical characteristics, [(99m)Tc/Tricine/HYNIC]UBI 29-41 shows promise as a tracer for infection imaging that allows early diagnosis (30 min) of infection.
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Affiliation(s)
- Mostafa Gandomkar
- Nuclear Science Research School, Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran, Tehran, 11365-3486, Iran.
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Brouwer CPJM, Welling MM. Various routes of administration of (99m)Tc-labeled synthetic lactoferrin antimicrobial peptide hLF 1-11 enables monitoring and effective killing of multidrug-resistant Staphylococcus aureus infections in mice. Peptides 2008; 29:1109-17. [PMID: 18423795 DOI: 10.1016/j.peptides.2008.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Revised: 03/03/2008] [Accepted: 03/05/2008] [Indexed: 10/22/2022]
Abstract
The synthetic antimicrobial peptide representative of the first 11 N-terminal amino acids of human lactoferrin (hLF 1-11) kills multidrug-resistant Staphylococcus aureus (MRSA). This study displays antimicrobial activity of hLF 1-11, via various routes of administration, against MRSA infections in mice. Radiolabeling hLF 1-11 with technetium-99m ((99m)Tc-hLF 1-11) enables scintigraphic monitoring directly after administration. (99m)Tc-hLF 1-11 was taken up by the gall bladder, intestines, and kidneys. Most of the radioactivity was captured in the urinary bladder and about 1% of the injected dose accumulated into infected thigh muscles. At 2 or 24h after either intravenously, subcutaneously, intraperitoneally, or orally injected a single dose of 0.04 mg/kg hLF 1-11 in mice significantly reduced (20-60 times) the number of viable MRSA. In a dose-response setting in immunocompetent mice maximum bactericidal effects (10,000 times reduction) of intravenously injected (99m)Tc-hLF 1-11 was seen with 40 mg/kg whereas the same dose of orally administered (99m)Tc-hLF 1-11 induced about approximately 100 times reduction. In conclusion, intravenously and orally administrated (99m)Tc-hLF 1-11 accumulates in infected tissues and is highly effective against experimental infections with MRSA. Moreover, scintigraphy is an excellent tool to study the pharmacology of experimental compounds and to determine the uptake in infected tissues.
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Affiliation(s)
- Carlo P J M Brouwer
- Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center (LUMC), Leiden, The Netherlands
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Brouwer CPJM, Wulferink M, Welling MM. The Pharmacology of Radiolabeled Cationic Antimicrobial Peptides. J Pharm Sci 2008; 97:1633-51. [PMID: 17786940 DOI: 10.1002/jps.21034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Cationic antimicrobial peptides are good candidates for new diagnostics and antimicrobial agents. They can rapidly kill a broad range of microbes and have additional activities that have impact on the quality and effectiveness of innate responses and inflammation. Furthermore, the challenge of bacterial resistance to conventional antibiotics and the unique mode of action of antimicrobial peptides have made such peptides promising candidates for the development of a new class of antibiotics. This review focuses on antimicrobial peptides as a topic for molecular imaging, infection detection, treatment monitoring and additionally, displaying microbicidal activities. A scintigraphic approach to studying the pharmacokinetics of antimicrobial peptides in laboratory animals has been developed. The peptides were labeled with technetium-99m and, after intravenous injection into laboratory animals, scintigraphy allowed real-time, whole body imaging and quantitative biodistribution studies of delivery of the peptides to the various body compartments. Antimicrobial peptides rapidly accumulated at sites of infection but not at sites of sterile inflammation, indicating that radiolabeled cationic antimicrobial peptides could be used for the detection of infected sites. As the number of viable micro-organisms determines the rate of accumulation of these peptides, radiolabeled antimicrobial peptides enabled to determine the efficacy of antibacterial therapy in animals to be monitored as well to quantify the delivery of antimicrobial peptides to the site of infection. The scintigraphic approach provides to be a reliable method for investigating the pharmacokinetics of small cationic antimicrobial peptides in animals and offers perspective for diagnosis of infections, monitoring antimicrobial therapy, and most important, alternative antimicrobial treatment infections with multi-drug resistant micro-organisms in humans.
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Walker RC, Jones-Jackson LB, Martin W, Habibian MR, Delbeke D. New imaging tools for the diagnosis of infection. Future Microbiol 2007; 2:527-54. [DOI: 10.2217/17460913.2.5.527] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Infection imaging became widespread in 1971 with the release of 67Ga citrate. Multiphase skeletal scintigraphy and radiolabeled white blood cells (WBCs) have since become the most widespread clinically used agents for the imaging of infection. A wide variety of other radiolabeled probes are under investigation, based on antibodies, cytokines, assorted proteins and other molecules, alone or in various combinations. However, these latter agents, with a few exceptions, are not routinely used clinically. Radiolabeled ciprofloxacin represents the first attempt to develop an infection-specific imaging agent (most infection-imaging probes localized nonspecifically to inflammation as well), but it has not proven superior to radiolabeled WBCs or 18F-fluoro-deoxy-glucose (FDG) PET. Because of the ability to combine exquisite anatomic detail with focal uptake of 18F-FDG, PET–computed tomography has achieved great success in the detection and localization of infection, including in clinically adverse conditions. Despite these advances, at this time an infection-specific imaging agent does not exist.
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Affiliation(s)
- Ronald C Walker
- Associate Professor Vanderbilt University Medical Center, Department of Radiology & Radiological Sciences, 1161 21st Avenue South, CCC-1121 MCN, Nashville, TN 37232-2675, USA
| | - Laurie B Jones-Jackson
- Associate Professor Vanderbilt University Medical Center, Department of Radiology & Radiological Sciences, 1161 21st Avenue South, CCC-1121 MCN, Nashville, TN 37232-2675, USA
| | - William Martin
- Associate Professor Vanderbilt University Medical Center, Department of Radiology & Radiological Sciences, 1161 21st Avenue South, CCC-1121 MCN, Nashville, TN 37232-2675, USA
| | - M Reza Habibian
- Associate Professor Vanderbilt University Medical Center, Department of Radiology & Radiological Sciences, 1161 21st Avenue South, CCC-1121 MCN, Nashville, TN 37232-2675, USA
| | - Dominique Delbeke
- Professor Vanderbilt University Medical Center, Department of Radiology & Radiological Sciences, 1161 21st Avenue South, CCC-1121 MCN, Nashville, TN 37232-2675, USA
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Welling MM, Brouwer CPJM, van 't Hof W, Veerman ECI, Amerongen AVN. Histatin-derived monomeric and dimeric synthetic peptides show strong bactericidal activity towards multidrug-resistant Staphylococcus aureus in vivo. Antimicrob Agents Chemother 2007; 51:3416-9. [PMID: 17620386 PMCID: PMC2043174 DOI: 10.1128/aac.00196-07] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Homodimerization of histatin-derived peptides generally led to improved bactericidal activity against Staphylococcus aureus in vitro. In vivo, monomers and dimers were equally active in killing bacteria in mice with a soft tissue infection. Altogether, these peptides are promising compounds for the development of novel therapeutics against infections with drug-resistant bacteria.
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Affiliation(s)
- Mick M Welling
- Section Nuclear Medicine, Division of Radiology, Leiden University Medical Center, Room C4-R-77, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
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Fonseca AS, Frydman JNG, Rocha VC, Bernardo-Filho M. Acetylsalicylic acid decreases the labeling of blood constituents with technetium-99M. ACTA BIOLOGICA HUNGARICA 2007; 58:187-98. [PMID: 17585508 DOI: 10.1556/abiol.58.2007.2.5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Acetylsalicylic acid is the most widely used drug as antipyretic, analgesic, anti-inflammatory agent and for secondary prevention of thrombotic phenomena in the heart, brain and peripheral circulation. Drugs can modify the labeling of blood constituents with technetium-99m (99mTc). This work has evaluated the effect of in vivo treatment with acetylsalicylic acid on the in vitro labeling of the blood constituents with 99mTc. Wistar rats were treated with different doses (1.5, 3.0 and 6.0 mg/kg) of acetylsalicylic acid during 1 hour. At higher dose used (6.0 mg/kg) animals were treated during different period of time (0.25, 1.0 and 4.0 hours). Animals treated with physiologic saline solution were used as control. After the labeled process; plasma (P), blood cells (BC), insoluble (IF-P, IF-BC) and soluble (SF-P, SF-BC) fractions were separated. Afterwards, the percentage of radioactivity (%ATI) in each fraction was calculated. The treatment during 1 hour with acetylsalicylic acid at higher dose has significantly (p < 0.05) modified the fixation of 99mTc on blood cells. Considering the results, we suggest that acetylsalicylic acid used at therapeutic doses may interfere with the nuclear medicine procedures related to these blood constituents.
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Affiliation(s)
- A S Fonseca
- Departamento de Farmacologia e Psicobiologia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brasil.
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Sarda-Mantel L, Saleh-Mghir A, Welling MM, Meulemans A, Vrigneaud JM, Raguin O, Hervatin F, Martet G, Chau F, Lebtahi R, Le Guludec D. Evaluation of 99mTc-UBI 29-41 scintigraphy for specific detection of experimental Staphylococcus aureus prosthetic joint infections. Eur J Nucl Med Mol Imaging 2007; 34:1302-9. [PMID: 17334764 DOI: 10.1007/s00259-007-0368-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Accepted: 12/26/2006] [Indexed: 12/11/2022]
Abstract
PURPOSE (99m)Tc-UBI 29-41 (UBI), an antimicrobial peptide, specifically targets bacteria. We tested the ability of UBI to discriminate between infected and uninfected prosthetic joints using a rabbit model previously validated. METHODS Left knee arthroplasty was performed on 20 New Zealand rabbits, then 10(7) cfu of S. aureus (n = 12) or sterile saline (n = 8) was injected into the joint. On days 9 and 20 after surgery, planar UBI scintigraphy was performed in six infected and four uninfected rabbits, 1 h and 4 h p.i. (150 MBq), on a gamma camera. Operated-to-normal knee activity ratio (ONKR) was calculated on each scintigram. Then, after sacrifice, tissue samples of both knees were counted in a gamma counter. RESULTS One rabbit injected with sterile saline had cutaneous infection at sacrifice and was excluded from analysis. ONKR was higher in infected than in uninfected animals 4 h p.i. 20 days after surgery: 1.75 +/- 0.48 vs 1.13 +/- 0.11, p = 0.04. From 1 h to 4 h p.i., ONKR increased in 9/12 infected and 0/7 uninfected animals. According to UBI uptake intensity and kinetics, scintigraphy was truly positive in all infected cases on day 9 and in four of six infected cases on day 20. It was truly negative in two of three sterile inflamed prosthetic knees on day 9, and in all cases on day 20. Biodistribution studies revealed increased UBI uptake in periprosthetic tissues in all animals 9 days after surgery, and only in infected animals on day 20. CONCLUSION In this experimental study, (99m)Tc-UBI 29-41 scintigraphy permitted the early detection of acute prosthetic joint infection, and exclusion of infection in chronic sterile prosthetic joint inflammation.
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Radiopharmaceuticals. Clin Nucl Med 2006. [DOI: 10.1201/b13348-84] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Brouwer CPJM, Bogaards SJP, Wulferink M, Velders MP, Welling MM. Synthetic peptides derived from human antimicrobial peptide ubiquicidin accumulate at sites of infections and eradicate (multi-drug resistant) Staphylococcus aureus in mice. Peptides 2006; 27:2585-91. [PMID: 16814900 DOI: 10.1016/j.peptides.2006.05.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Revised: 05/22/2006] [Accepted: 05/22/2006] [Indexed: 10/24/2022]
Abstract
The presence and antimicrobial activity of antimicrobial peptides (AMPs) has been widely recognized as an evolutionary preserved part of the innate immune system. Based on evidence in animal models and humans, AMPs are now positioned as novel anti-infective agents. The current study aimed to evaluate the potential antimicrobial activity of ubiquicidin and small synthetic fragments thereof towards methicillin resistant Staphylococcus aureus (MRSA), as a high priority target for novel antibiotics. In vitro killing of MRSA by synthetic peptides derived from the alpha-helix or beta-sheet domains of the human cationic peptide ubiquicidin (UBI 1-59), allowed selection of AMPs for possible treatment of MRSA infections. The strongest antibacterial activity was observed for the entire peptide UBI 1-59 and for synthetic fragments comprising amino acids 31-38. The availability, chemical synthesis opportunities, and size of these small peptides, combined with their strong antimicrobial activity towards MRSA make these compounds promising candidates for antimicrobial therapy and detection of infections in man.
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