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Zimmermann CM, Baldassi D, Chan K, Adams NBP, Neumann A, Porras-Gonzalez DL, Wei X, Kneidinger N, Stoleriu MG, Burgstaller G, Witzigmann D, Luciani P, Merkel OM. Spray drying siRNA-lipid nanoparticles for dry powder pulmonary delivery. J Control Release 2022; 351:137-150. [PMID: 36126785 PMCID: PMC7613708 DOI: 10.1016/j.jconrel.2022.09.021] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 09/09/2022] [Accepted: 09/12/2022] [Indexed: 11/17/2022]
Abstract
While all the siRNA drugs on the market target the liver, the lungs offer a variety of currently undruggable targets which could potentially be treated with RNA therapeutics. Hence, local, pulmonary delivery of RNA nanoparticles could finally enable delivery beyond the liver. The administration of RNA drugs via dry powder inhalers offers many advantages related to physical, chemical and microbial stability of RNA and nanosuspensions. The present study was therefore designed to test the feasibility of engineering spray dried lipid nanoparticle (LNP) powders. Spray drying was performed using 5% lactose solution (m/V), and the targets were set to obtain nanoparticle sizes after redispersion of spray-dried powders around 150 nm, a residual moisture level below 5%, and RNA loss below 15% at maintained RNA bioactivity. The LNPs consisted of an ionizable cationic lipid which is a sulfur-containing analog of DLin-MC3-DMA, a helper lipid, cholesterol, and PEG-DMG encapsulating siRNA. Prior to the spray drying, the latter process was simulated with a novel dual emission fluorescence spectroscopy method to preselect the highest possible drying temperature and excipient solution maintaining LNP integrity and stability. Through characterization of physicochemical and aerodynamic properties of the spray dried powders, administration criteria for delivery to the lower respiratory tract were fulfilled. Spray dried LNPs penetrated the lung mucus layer and maintained bioactivity for >90% protein downregulation with a confirmed safety profile in a lung adenocarcinoma cell line. Additionally, the spray dried LNPs successfully achieved up to 50% gene silencing of the house keeping gene GAPDH in ex vivo human precision-cut lung slices at without increasing cytokine levels. This study verifies the successful spray drying procedure of LNP-siRNA systems maintaining their integrity and mediating strong gene silencing efficiency on mRNA and protein levels both in vitro and ex vivo. The successful spray drying procedure of LNP-siRNA formulations in 5% lactose solution creates a novel siRNA-based therapy option to target respiratory diseases such as lung cancer, asthma, COPD, cystic fibrosis and viral infections.
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Affiliation(s)
- Christoph M Zimmermann
- Department of Pharmacy, Pharmaceutical Technology and Biopharmacy, Ludwig-Maximilians Universität München, 81377 Munich, Germany; Department of Chemistry, Biochemistry and Pharmacy, University Bern, Freiestrasse 3, Bern, Switzerland
| | - Domizia Baldassi
- Department of Pharmacy, Pharmaceutical Technology and Biopharmacy, Ludwig-Maximilians Universität München, 81377 Munich, Germany
| | - Karen Chan
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada; NanoMedicines Innovation Network (NMIN), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Nathan B P Adams
- Nanotemper Technologies GmbH, Flößergasse 4, 81369 Munich, Germany
| | - Alina Neumann
- Nanotemper Technologies GmbH, Flößergasse 4, 81369 Munich, Germany
| | - Diana Leidy Porras-Gonzalez
- Institute of Lung Health and Immunity (LHI) and Comprehensive Pneumology Center (CPC) with the CPC-M bioArchive, Helmholtz Munich, Member of the German Center for Lung Research (DZL), Munich, Germany
| | - Xin Wei
- Institute of Lung Health and Immunity (LHI) and Comprehensive Pneumology Center (CPC) with the CPC-M bioArchive, Helmholtz Munich, Member of the German Center for Lung Research (DZL), Munich, Germany
| | - Nikolaus Kneidinger
- Department of Medicine V, University Hospital, LMU Munich, Member of the German Center for Lung Research (DZL), Munich, Germany
| | - Mircea Gabriel Stoleriu
- Center for Thoracic Surgery Munich, Ludwig-Maximilians-University of Munich (LMU) and Asklepios Pulmonary Hospital, Marchioninistraße 15, 81377 Munich and Robert-Koch-Allee 2, 82131 Gauting, Germany
| | - Gerald Burgstaller
- Institute of Lung Health and Immunity (LHI) and Comprehensive Pneumology Center (CPC) with the CPC-M bioArchive, Helmholtz Munich, Member of the German Center for Lung Research (DZL), Munich, Germany
| | - Dominik Witzigmann
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada; NanoMedicines Innovation Network (NMIN), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada; NanoVation Therapeutics Inc., 2405 Wesbrook Mall 4th Floor, Vancouver V6T 1Z3, Canada.
| | - Paola Luciani
- Department of Chemistry, Biochemistry and Pharmacy, University Bern, Freiestrasse 3, Bern, Switzerland.
| | - Olivia M Merkel
- Department of Pharmacy, Pharmaceutical Technology and Biopharmacy, Ludwig-Maximilians Universität München, 81377 Munich, Germany; Institute of Lung Health and Immunity (LHI) and Comprehensive Pneumology Center (CPC) with the CPC-M bioArchive, Helmholtz Munich, Member of the German Center for Lung Research (DZL), Munich, Germany.
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Freeze-drying: A Flourishing Strategy to Fabricate Stable Pharmaceutical and Biological Products. Int J Pharm 2022; 628:122233. [DOI: 10.1016/j.ijpharm.2022.122233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/07/2022] [Accepted: 09/20/2022] [Indexed: 11/21/2022]
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Keil TWM, Zimmermann C, Baldassi D, Adams F, Friess W, Mehta A, Merkel OM. Impact of crystalline and amorphous matrices on successful spray drying of siRNA polyplexes for inhalation of nano-in-microparticles. ADVANCED THERAPEUTICS 2021; 4:2100073. [PMID: 34337144 PMCID: PMC7611418 DOI: 10.1002/adtp.202100073] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Indexed: 11/09/2022]
Abstract
To develop stable and inhalable dry powder formulations with long shelf life, we spray dried polyplexes consisting of siRNA and a polyethylenimine based block copolymer in presence of mannitol or trehalose. We investigated the effect of inlet (T-In) and outlet (T-Out) temperature on the recovery of siRNA as well as adsorption effects within the tubing material. Choosing a low abrasion silicon tubing prevented siRNA loss due to adsorption. Mannitol and trehalose formulations preserved siRNA integrity regardless of excipient concentration and temperature at T-Out below the siRNA melting temperature. Trehalose formulations allowed full siRNA recovery whereas mannitol formulations resulted in spray drying induced losses of ~20 % siRNA and of 50-60 % polymer. Mannitol formulations showed optimal aerodynamic characteristics as confirmed by next generation impaction analysis based upon siRNA content. All spray dried formulations resulted in GFP silencing comparable or better than freshly prepared polyplexes. To test if the observed results could be transferred, formulations of siRNA and transferrin-PEI conjugates were spray dried, characterized and used to transfect primary human T cells ex vivo. Results confirmed successful silencing of the Th2 transcription factor GATA3 in primary CD4+ T cells with spray dried formulations as a potential treatment for severe asthma.
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Affiliation(s)
- Tobias WM Keil
- Department of Pharmacy, Pharmaceutical Technology and Biopharmacy, Ludwig-Maximilians Universität München, 81377 Munich, Germany
| | - Christoph Zimmermann
- Department of Pharmacy, Pharmaceutical Technology and Biopharmacy, Ludwig-Maximilians Universität München, 81377 Munich, Germany
| | - Domizia Baldassi
- Department of Pharmacy, Pharmaceutical Technology and Biopharmacy, Ludwig-Maximilians Universität München, 81377 Munich, Germany
| | - Friederike Adams
- Department of Pharmacy, Pharmaceutical Technology and Biopharmacy, Ludwig-Maximilians Universität München, 81377 Munich, Germany
| | - Wolfgang Friess
- Department of Pharmacy, Pharmaceutical Technology and Biopharmacy, Ludwig-Maximilians Universität München, 81377 Munich, Germany
| | - Aditi Mehta
- Department of Pharmacy, Pharmaceutical Technology and Biopharmacy, Ludwig-Maximilians Universität München, 81377 Munich, Germany
| | - Olivia M Merkel
- Department of Pharmacy, Pharmaceutical Technology and Biopharmacy, Ludwig-Maximilians Universität München, 81377 Munich, Germany
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Trenkenschuh E, Friess W. Freeze-drying of nanoparticles: How to overcome colloidal instability by formulation and process optimization. Eur J Pharm Biopharm 2021; 165:345-360. [PMID: 34052428 DOI: 10.1016/j.ejpb.2021.05.024] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/03/2021] [Accepted: 05/23/2021] [Indexed: 11/29/2022]
Abstract
Lyophilization of nanoparticle (NP) suspensions is a promising technology to improve stability, especially during long-term storage, and offers new routes of administration in solid state. Although considered as a gentle drying process, freeze-drying is also known to cause several stresses leading to physical instability, e.g. aggregation, fusion, or content leakage. NPs are heterogeneous regarding their physico-chemical properties which renders them different in their sensitivity to lyophilization stress and upon storage. But still basic concepts can be deducted. We summarize basic colloidal stabilization mechanisms of NPs in the liquid and the dried state. Furthermore, we give information about stresses occurring during the freezing and the drying step of lyophilization. Subsequently, we review the most commonly investigated NP types including lipophilic, polymeric, or vesicular NPs regarding their particle properties, stabilization mechanisms in the liquid state, and important freeze-drying process, formulation and storage strategies. Finally, practical advice is provided to facilitate purposeful formulation and process development to achieve NP lyophilizates with high colloidal stability.
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Affiliation(s)
- Eduard Trenkenschuh
- Pharmaceutical Technology and Biopharmaceutics, Department of Pharmacy, Ludwig-Maximilians-Universitaet Muenchen, 81377 Munich, Germany
| | - Wolfgang Friess
- Pharmaceutical Technology and Biopharmaceutics, Department of Pharmacy, Ludwig-Maximilians-Universitaet Muenchen, 81377 Munich, Germany.
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Insights into Terminal Sterilization Processes of Nanoparticles for Biomedical Applications. Molecules 2021; 26:molecules26072068. [PMID: 33916823 PMCID: PMC8038324 DOI: 10.3390/molecules26072068] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/25/2021] [Accepted: 03/30/2021] [Indexed: 12/28/2022] Open
Abstract
Nanoparticles possess a huge potential to be employed in numerous biomedical purposes; their applications may include drug delivery systems, gene therapy, and tissue engineering. However, the in vivo use in biomedical applications requires that nanoparticles exhibit sterility. Thus, diverse sterilization techniques have been developed to remove or destroy microbial contamination. The main sterilization methods include sterile filtration, autoclaving, ionizing radiation, and nonionizing radiation. Nonetheless, the sterilization processes can alter the stability, zeta potential, average particle size, and polydispersity index of diverse types of nanoparticles, depending on their composition. Thus, these methods may produce unwanted effects on the nanoparticles' characteristics, affecting their safety and efficacy. Moreover, each sterilization method possesses advantages and drawbacks; thus, the suitable method's choice depends on diverse factors such as the formulation's characteristics, batch volume, available methods, and desired application. In this article, we describe the current sterilization methods of nanoparticles. Moreover, we discuss the advantages and drawbacks of these methods, pointing out the changes in nanoparticles' biological and physicochemical characteristics after sterilization. Our main objective was to offer a comprehensive overview of terminal sterilization processes of nanoparticles for biomedical applications.
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Ossama M, Hathout RM, Attia DA, Mortada ND. Augmented cytotoxicity using the physical adsorption of Poloxamer 188 on allicin-loaded gelatin nanoparticles. J Pharm Pharmacol 2021; 73:664-672. [PMID: 33772296 DOI: 10.1093/jpp/rgab006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/13/2021] [Indexed: 11/13/2022]
Abstract
OBJECTIVES The aim of this work was to study the effect of the physically adsorbed Poloxamer 188 coating polymer on the cytotoxic activity of allicin-loaded gelatin nanoparticles. METHODS The double desolvation method was utilised to prepare the nanoparticles which were characterised for particle size (PS), polydispersity index (PDI) and zeta potential and visualised using transmission electron microscopy. The coating density of the used polymer was determined using 1H-nuclear magnetic resonance (1H-NMR); 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to evaluate the cytotoxicity on HepG-2 cell lines. KEY FINDINGS The particles were spherical possessing a PS of 714 ± 25.21 nm and a PDI of 0.663 ± 0.143. These results together with the 1H-NMR results analysis confirmed the efficient coating of Poloxamer 188. The coating of particles rendered them more cytotoxic, scoring an IC50 of 6.736 µm (2-folds lower than the uncoated counter parts and 4-folds lesser than the allicin solution), and apt for cancer-targeting. Moreover, the prepared nanoparticles were stable to gamma-sterilisation and to a storage of 12 months. CONCLUSIONS Augmented cytotoxicity on HepG-2 cell lines was obtained using the physical adsorption of an abundant and relatively cheap material, Poloxamer 188, on allicin-loaded gelatin nanoparticles.
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Affiliation(s)
- Muhammed Ossama
- Department of Pharmaceutics and Industrial Pharmacy, The British University in Egypt (BUE), Cairo, Egypt
| | - Rania M Hathout
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
| | - Dalia A Attia
- Department of Pharmaceutics and Industrial Pharmacy, The British University in Egypt (BUE), Cairo, Egypt
| | - Nahed D Mortada
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt
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Bai Y, Moeinzadeh S, Kim S, Park Y, Lui E, Tan H, Zhao W, Zhou X, Yang YP. Development of PLGA-PEG-COOH and gelatin-based microparticles dual delivery system and E-beam sterilization effects for controlled release of BMP-2 and IGF-1. PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION : MEASUREMENT AND DESCRIPTION OF PARTICLE PROPERTIES AND BEHAVIOR IN POWDERS AND OTHER DISPERSE SYSTEMS 2020; 37:2000180. [PMID: 33384477 PMCID: PMC7771709 DOI: 10.1002/ppsc.202000180] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The purpose of this study was to develop a PLGA-PEG-COOH- and gelatin-based microparticles (MPs) dual delivery system for release of BMP-2 and IGF-1. We made and characterized the delivery system based on its morphology, loading capacity, Encapsulation efficiency and release kinetics. Second, we examined the effects of electron beam (EB) sterilization on BMP-2 and IGF-1 loaded MPs and their biological effects. Third, we evaluated the synergistic effect of a controlled dual release of BMP-2 and IGF-1 on osteogenesis of MSCs. Encapsulation efficiency of growth factors into gelatin and PLGA-PEG-COOH MPs are in the range of 64.78% to 76.11%. E-beam sterilized growth factor delivery systems were effective in significantly promoting osteogenesis of MSCs, although E-beam sterilization decreased the bioactivity of growth factors in MPs by approximately 22%. BMP-2 release behavior from gelatin MPs/PEG hydrogel shows a faster release (52.7%) than that of IGF-1 from the PLGA-PEG-COOH MPs/PEG hydrogel (27.3%). The results demonstrate that the gelatin and PLGA-PEG-COOH MPs based delivery system could realize temporal release of therapeutic biomolecules by incorporating different growth factors into distinct microparticles. EB sterilization was an accessible method for sterilizing growth factors loaded carriers, which could pave the way for implementing growth factor delivery in clinical applications.
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Affiliation(s)
- Yan Bai
- Department of Orthopaedic Surgery, Stanford University, CA, USA
- School of Pharmacy, Chongqing Medical University, Chongqing, China
| | | | - Sungwoo Kim
- Department of Orthopaedic Surgery, Stanford University, CA, USA
| | - Youngbum Park
- Department of Orthopaedic Surgery, Stanford University, CA, USA
- Dept. Prosthodontics, Yonsei University College of Dentistry, Seoul 120-752, Korea
| | - Elaine Lui
- Department of Orthopaedic Surgery, Stanford University, CA, USA
- Department of Mechanical Engineering, Stanford University, CA, USA
| | - Hua Tan
- School of Biomedical Informatics, the University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Weiling Zhao
- School of Biomedical Informatics, the University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Xiaobo Zhou
- School of Biomedical Informatics, the University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Yunzhi Peter Yang
- Department of Orthopaedic Surgery, Stanford University, CA, USA
- Department of Materials Science and Engineering, Stanford University, CA, USA
- Department of Bioengineering, Stanford University, CA, USA
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Pali-Schöll I, DeBoer DJ, Alessandri C, Seida AA, Mueller RS, Jensen-Jarolim E. Formulations for Allergen Immunotherapy in Human and Veterinary Patients: New Candidates on the Horizon. Front Immunol 2020; 11:1697. [PMID: 32849594 PMCID: PMC7417425 DOI: 10.3389/fimmu.2020.01697] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 06/25/2020] [Indexed: 12/20/2022] Open
Abstract
Allergen immunotherapy is currently the only causal treatment for allergic diseases in human beings and animals. It aims to re-direct the immune system into a tolerogenic or desensitized state. Requirements include clinical efficacy, safety, and schedules optimizing patient or owner compliance. To achieve these goals, specific allergens can be formulated with adjuvants that prolong tissue deposition and support uptake by antigen presenting cells, and/or provide a beneficial immunomodulatory action. Here, we depict adjuvant formulations being investigated for human and veterinary allergen immunotherapy.
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Affiliation(s)
- Isabella Pali-Schöll
- University of Veterinary Medicine, Vienna, Austria.,Institute of Pathophysiology and Allergy Research, Center of Physiology, Pathophysiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Douglas J DeBoer
- Dermatology/Allergy Section, Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, United States
| | | | - Ahmed Adel Seida
- Department of Microbiology and Immunology, Faculty of Veterinary Medicine, Cairo University, Cairo, Egypt
| | - Ralf S Mueller
- Centre for Clinical Veterinary Medicine, University of Munich, Munich, Germany
| | - Erika Jensen-Jarolim
- Institute of Pathophysiology and Allergy Research, Center of Physiology, Pathophysiology and Immunology, Medical University of Vienna, Vienna, Austria
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Klier J, Bartl C, Geuder S, Geh KJ, Reese S, Goehring LS, Winter G, Gehlen H. Immunomodulatory asthma therapy in the equine animal model: A dose-response study and evaluation of a long-term effect. Immun Inflamm Dis 2019; 7:130-149. [PMID: 31141308 PMCID: PMC6688086 DOI: 10.1002/iid3.252] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 04/08/2019] [Accepted: 04/12/2019] [Indexed: 12/18/2022] Open
Abstract
INTRODUCTION Equine asthma represents a naturally occurring animal model for human allergic neutrophilic asthma. Inhalative nanoparticle-bound cytosine-phosphate-guanosine (CpG-GNP) immunotherapy, independent of specific allergens, has already shown promising clinical and immunological results in previous studies and offers the possibility to treat the underlying cause of the disease. This study analyses the relationship between dose and response, and evaluates a possible long-term effect. METHODS In the prospective, randomised, double-blind clinical field study, 29 horses suffering from equine asthma received 10 inhalation treatments with either 187.5 µg CpG-GNP (CpG single dose [CpGsd]; n = 11), 375 µg CpG-GNP double dose (CpG double dose [CpGdd]; n = 9) (q48h for 20 days) or 1600 µg beclomethasone (n = 9) (q24h for 10 days). Each horse was examined three times: before the treatment (I), immediately after the 10 inhalations (II), and 8 weeks after the final inhalation (III). The three groups were compared according to clinical and laboratory parameters. The study examined the sustainability of the long-term effect of the treatment after 8 weeks, as well as the tolerability of the formula as a double dose. RESULTS The CpGsd resulted in a significant improvement in 82% of the parameters, the CpGdd in 72%. In the long-term evaluation, the CpGsd showed a significant improvement in 100% of the parameters in comparison to the initial values, the CpGdd in 67%. On the immunological level, the bronchoalveolar lavage revealed a significant reduction of IL-4, IL-8, and interferon-γ. CONCLUSION Both CpG groups displayed significant improvements in clinical and laboratory parameters, especially regarding the long-term effect of CpGsd. Doubling the CpG dose did not result in any improvement in comparison to the original single dose. On the immunological level, an anti-inflammatory, as well as an immunomodulatory effect, apart from a Th2-dominated immune response, could be observed. This immunomodulatory inhalation treatment could indicate a new possibility for human allergic asthma therapy.
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Affiliation(s)
- John Klier
- Centre for Clinical Veterinary Medicine, Equine ClinicLudwig‐Maximilians‐UniversityMunichGermany
| | - Carolin Bartl
- Centre for Clinical Veterinary Medicine, Equine ClinicLudwig‐Maximilians‐UniversityMunichGermany
- Department of Veterinary Medicine, Equine Clinic, Surgery and RadiologyFree University of BerlinBerlinGermany
| | - Sabine Geuder
- Centre for Clinical Veterinary Medicine, Equine ClinicLudwig‐Maximilians‐UniversityMunichGermany
| | - Katharina J. Geh
- Department of Pharmacy, Pharmaceutical Technology and BiopharmaceuticsLudwig‐Maximilians‐UniversityMunichGermany
| | - Sven Reese
- Department of Veterinary Medicine, Equine Clinic, Surgery and RadiologyFree University of BerlinBerlinGermany
| | - Lutz S. Goehring
- Centre for Clinical Veterinary Medicine, Equine ClinicLudwig‐Maximilians‐UniversityMunichGermany
| | - Gerhard Winter
- Department of Pharmacy, Pharmaceutical Technology and BiopharmaceuticsLudwig‐Maximilians‐UniversityMunichGermany
| | - Heidrun Gehlen
- Department of Veterinary Medicine, Equine Clinic, Surgery and RadiologyFree University of BerlinBerlinGermany
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