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Paik CB, Pei M, Oghalai JS. Review of blast noise and the auditory system. Hear Res 2022; 425:108459. [PMID: 35181171 PMCID: PMC9357863 DOI: 10.1016/j.heares.2022.108459] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 11/22/2022]
Abstract
The auditory system is particularly vulnerable to blast injury due to the ear's role as a highly sensitive pressure transducer. Over the past several decades, studies have used a variety of animal models and experimental procedures to recreate blast-induced acoustic trauma. Given the developing nature of this field and our incomplete understanding of molecular mechanisms underlying blast-related auditory disturbances, an updated discussion about these studies is warranted. Here, we comprehensively review well-established blast-related auditory pathology including tympanic membrane perforation and hair cell loss. In addition, we discuss important mechanistic studies that aim to bridge gaps in our current understanding of the molecular and microstructural events underlying blast-induced cochlear, auditory nerve, brainstem, and central auditory system damage. Key findings from the recent literature include the association between endolymphatic hydrops and cochlear synaptic loss, blast-induced neuroinflammatory markers in the peripheral and central auditory system, and therapeutic approaches targeting biochemical markers of blast injury. We conclude that blast is an extreme form of noise exposure. Blast waves produce cochlear damage that appears similar to, but more extreme than, the standard noise exposure protocols used in auditory research. However, experimental variations in studies of blast-induced acoustic trauma make it challenging to compare and interpret data across studies.
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Affiliation(s)
- Connie B Paik
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA USA
| | - Michelle Pei
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA USA
| | - John S Oghalai
- Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine of the University of Southern California, Los Angeles, CA USA.
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Hamidzadeh K, Westcott J, Wourms N, Shay AE, Panigrahy A, Martin MJ, Nshimiyimana R, Serhan CN. A newly synthesized 17-epi-NeuroProtectin D1/17-epi-Protectin D1: Authentication and functional regulation of Inflammation-Resolution. Biochem Pharmacol 2022; 203:115181. [PMID: 35850309 PMCID: PMC9398963 DOI: 10.1016/j.bcp.2022.115181] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 12/15/2022]
Abstract
The production of specialized pro-resolving mediators (SPMs) during the resolution phase in the inflammatory milieu is key to orchestrating the resolution of the acute inflammatory response. 17-epi-neuroprotectin D1/17-epi-protectin D1 (17-epi-NPD1/17-epi-PD1: 10R,17R-dihydroxy-4Z,7Z,11E,13E,15Z,19Z-docosahexaenoic acid) is an SPM of the protectin family, biosynthesized from docosahexaenoic acid (DHA), that exhibits both potent anti-inflammatory and neuroprotective functions. Here, we carried out a new commercial-scale synthesis of 17-epi-NPD1/17-epi-PD1 that enabled the authentication and confirmation of its potent bioactions in vivo and determination of its ability to activate human leukocyte phagocytosis. We provide evidence that this new synthetic 17-epi-NPD1/17-epi-PD1 statistically significantly increases human macrophage uptake of E. coli in vitro and confirm that it limits neutrophilic infiltration in vivo in a murine model of peritonitis. The physical properties of the new synthetic 17-epi-NPD1/17-epi-PD1, namely its ultra-violet absorbance, chromatography, and tandem mass spectrometry fragmentation pattern, matched those of the originally synthesized 17-epi-NPD1/17-epi-PD1. In addition, we verified the structure and complete stereochemical assignment of this new synthetic 17-epi-NPD1/17-epi-PD1 using nuclear magnetic resonance (NMR) spectroscopy. Together, these results authenticate this 17-epi-NPD1/17-epi-PD1 for its structure and potent pro-resolving functions.
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Affiliation(s)
- Kajal Hamidzadeh
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | | | | | - Ashley E Shay
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Anand Panigrahy
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | | | - Robert Nshimiyimana
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Charles N Serhan
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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