1
|
Ihler F, Freytag S, Kloos B, Spiegel JL, Haubner F, Canis M, Weiss BG, Bertlich M. Lipopolysaccharide decreases cochlear blood flow dose dependently in a guinea pig animal model via TNF signaling. Microcirculation 2021; 28:e12681. [PMID: 33501679 DOI: 10.1111/micc.12681] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/15/2021] [Accepted: 01/20/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To evaluate the effect of Lipopolysaccharide (LPS), a bacterial endotoxin on cochlear microcirculation, and its mode of action. METHODS Twenty-five Dunkin-Hartley guinea pigs were divided into five groups of five animals each. After surgical preparation, cochlear microcirculation was quantified by in vivo fluorescence microscopy. Placebo or LPS (1 mg, 10 µg, and 100 ng) was applied topically, and microcirculation was measured before and twice after application. A fifth group was pretreated with etanercept, a tumor necrosis factor (TNF) antagonist, and afterward the lowest LPS concentrations that yielded significant results (10 µg) were applied. RESULTS In the groups that had been treated with 1 mg and 10 µg LPS, a significant drop in cochlear microcirculation was observed after 30 (.791 ± .089 Arbitrary Units (AU), compared to baseline, and .888 ± .071AU) and 60 (.756 ± .101 AU and .817 ± .124 AU, respectively) minutes. The groups that had been treated with 100 ng LPS and that had been pretreated with etanercept showed no significant change in cochlear blood flow compared to placebo. CONCLUSION Lipopolysaccharide shows a dose-dependent effect on cochlear microcirculation; this effect can already be observed after 30 min. Pretreatment with etanercept can abrogate this effect, indicating that TNF mediates the effect of LPS on cochlear microcirculation.
Collapse
Affiliation(s)
- Friedrich Ihler
- Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig-Maximilians-University of Munich, Munich, Germany.,Walter Brendel Centre of Experimental Medicine, University of Munich Hospital, Munich, Germany
| | - Saskia Freytag
- Population Health and Immunity Division, Walter and Eliza Hall Institute, Parkville, Vic., Australia.,Department of Medical Biology, University of Melbourne, Melbourne, Vic., Australia
| | - Benedikt Kloos
- Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig-Maximilians-University of Munich, Munich, Germany.,Walter Brendel Centre of Experimental Medicine, University of Munich Hospital, Munich, Germany
| | - Jennifer Lee Spiegel
- Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Frank Haubner
- Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Martin Canis
- Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig-Maximilians-University of Munich, Munich, Germany.,Walter Brendel Centre of Experimental Medicine, University of Munich Hospital, Munich, Germany
| | - Bernhard G Weiss
- Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig-Maximilians-University of Munich, Munich, Germany.,Walter Brendel Centre of Experimental Medicine, University of Munich Hospital, Munich, Germany
| | - Mattis Bertlich
- Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig-Maximilians-University of Munich, Munich, Germany.,Walter Brendel Centre of Experimental Medicine, University of Munich Hospital, Munich, Germany
| |
Collapse
|
2
|
Kalinec GM, Lomberk G, Urrutia RA, Kalinec F. Resolution of Cochlear Inflammation: Novel Target for Preventing or Ameliorating Drug-, Noise- and Age-related Hearing Loss. Front Cell Neurosci 2017; 11:192. [PMID: 28736517 PMCID: PMC5500902 DOI: 10.3389/fncel.2017.00192] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 06/20/2017] [Indexed: 12/11/2022] Open
Abstract
A significant number of studies support the idea that inflammatory responses are intimately associated with drug-, noise- and age-related hearing loss (DRHL, NRHL and ARHL). Consequently, several clinical strategies aimed at reducing auditory dysfunction by preventing inflammation are currently under intense scrutiny. Inflammation, however, is a normal adaptive response aimed at restoring tissue functionality and homeostasis after infection, tissue injury and even stress under sterile conditions, and suppressing it could have unintended negative consequences. Therefore, an appropriate approach to prevent or ameliorate DRHL, NRHL and ARHL should involve improving the resolution of the inflammatory process in the cochlea rather than inhibiting this phenomenon. The resolution of inflammation is not a passive response but rather an active, highly controlled and coordinated process. Inflammation by itself produces specialized pro-resolving mediators with critical functions, including essential fatty acid derivatives (lipoxins, resolvins, protectins and maresins), proteins and peptides such as annexin A1 and galectins, purines (adenosine), gaseous mediators (NO, H2S and CO), as well as neuromodulators like acetylcholine and netrin-1. In this review article, we describe recent advances in the understanding of the resolution phase of inflammation and highlight therapeutic strategies that might be useful in preventing inflammation-induced cochlear damage. In particular, we emphasize beneficial approaches that have been tested in pre-clinical models of inflammatory responses induced by recognized ototoxic drugs such as cisplatin and aminoglycoside antibiotics. Since these studies suggest that improving the resolution process could be useful for the prevention of inflammation-associated diseases in humans, we discuss the potential application of similar strategies to prevent or mitigate DRHL, NRHL and ARHL.
Collapse
Affiliation(s)
- Gilda M Kalinec
- Laboratory of Auditory Cell Biology, Department of Head and Neck Surgery, David Geffen School of Medicine, University of CaliforniaLos Angeles, Los Angeles, CA, United States
| | - Gwen Lomberk
- Epigenetics and Chromatin Dynamics Laboratory, Translational Epigenomic Program, Center for Individualized Medicine (CIM) Mayo ClinicRochester, MN, United States
| | - Raul A Urrutia
- Epigenetics and Chromatin Dynamics Laboratory, Translational Epigenomic Program, Center for Individualized Medicine (CIM) Mayo ClinicRochester, MN, United States
| | - Federico Kalinec
- Laboratory of Auditory Cell Biology, Department of Head and Neck Surgery, David Geffen School of Medicine, University of CaliforniaLos Angeles, Los Angeles, CA, United States
| |
Collapse
|
3
|
Characterisation of cochlear inflammation in mice following acute and chronic noise exposure. Histochem Cell Biol 2016; 146:219-30. [PMID: 27109494 DOI: 10.1007/s00418-016-1436-5] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2016] [Indexed: 12/17/2022]
Abstract
Oxidative stress has been established as the key mechanism of the cochlear damage underlying noise-induced hearing loss, however, emerging evidence suggests that cochlear inflammation may also be a major contributor. This study aimed to improve our understanding of the cochlear inflammatory response associated with acute and chronic noise exposure. C57BL/6 mice were exposed to acute traumatic noise (100 dBSPL, 8-16 kHz for 24 h) and their cochleae collected at various intervals thereafter, up to 7 days. Using quantitative RT-PCR and immunohistochemistry, changes in expression levels of proinflammatory cytokines (TNF-α, IL-1β), chemokines (CCL2) and cell adhesion molecules (ICAM-1) were studied. All gene transcripts displayed similar dynamics of expression, with an early upregulation at 6 h post-exposure, followed by a second peak at 7 days. ICAM-1 immunoexpression increased significantly in the inferior region of the spiral ligament, peaking 24 h post-exposure. The early expression of proinflammatory mediators likely mediates the recruitment and extravasation of inflammatory cells into the noise-exposed cochlea. The occurrence of the latter expression peak is not clear, but it may be associated with reparative processes initiated in response to cochlear damage. Chronic exposure to moderate noise (90 dBSPL, 8-16 kHz, 2 h/day, up to 4 weeks) also elicited an inflammatory response, reaching a maximum after 2 weeks, suggesting that cochlear damage and hearing loss associated with chronic environmental noise exposure may be linked to inflammatory processes in the cochlea. This study thus provides further insight into the dynamics of the cochlear inflammatory response induced by exposure to acute and chronic noise.
Collapse
|
4
|
Tan WJT, Thorne PR, Vlajkovic SM. Noise-induced cochlear inflammation. World J Otorhinolaryngol 2013; 3:89-99. [DOI: 10.5319/wjo.v3.i3.89] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/08/2013] [Accepted: 08/20/2013] [Indexed: 02/06/2023] Open
Abstract
Hearing loss is the most common sensory disability with considerable social and economic implications. According to recent World Health Organization estimates, 360 million people worldwide suffer from moderate to profound hearing loss. Exposure to excessive noise is one of the major causes of sensorineural hearing loss, secondary only to age-related hearing loss (presbyacusis). Since cochlear tissues have limited abilities of repair and regeneration, this damage can be irreversible, leading to cochlear dysfunction and permanent hearing loss. Recent studies have shown that cochlear inflammation can be induced by noise exposure and contribute to the overall pathogenesis of cochlear injury and hearing loss. The cochlea is separated from the systemic circulation by the blood-labyrinth barrier, which is physiologically similar to the blood-brain barrier of the central nervous system. Because of this feature, the cochlea was originally considered an immunologically privileged organ. However, this postulate has been challenged by the evidence of an inflammatory response in the cochlea in the presence of bacterial or viral pathogens or antigens that can cause labyrinthitis. Although the main purpose of the inflammatory reaction is to protect against invading pathogens, the inflammatory response can also cause significant bystander injury to the delicate structures of the cochlea. The cochlear inflammatory response is characterised by the generation of proinflammatory mediators (cytokines, chemokines and adhesion molecules), and the recruitment of inflammatory cells (leukocytes). Here, we present an overview of the current research on cochlear inflammation, with particular emphasis on noise-induced cochlear inflammation. We also discuss treatment strategies aimed at the suppression of inflammation, which may potentially lead to mitigation of hearing loss.
Collapse
|
5
|
Smit AL, Stokroos RJ, Litjens SGH, Kremer B, Kramer BW. Potential role for lipopolysaccharide in congenital sensorineural hearing loss. J Med Microbiol 2010; 59:377-383. [PMID: 20093374 DOI: 10.1099/jmm.0.015792-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Congenital sensorineural hearing loss (SNHL) is common. In the Western world, the incidence is 1-3 per 1000 live births. The aetiology encompasses genetic and non-genetic factors accounting for 55 % and 45 % of cases, respectively. Reports that describe the contribution of intrauterine infection to the occurrence of congenital SNHL are limited, and comparative analysis of the different pathogens is lacking. Lipopolysaccharide (LPS), a product of bacteriolysis, has been demonstrated to be associated with inner ear damage in experimental studies. To elucidate the potential role of this toxin in congenital SNHL and to identify the pathogenesis and transmission routes, we reviewed the literature. We speculate that different routes of exposure to LPS in utero may result in congenital inner ear damage.
Collapse
Affiliation(s)
- A L Smit
- Department of Otorhinolaryngology/Head and NeckSurgery, Maastricht University Medical Centre, PO Box 5800, Maastricht, TheNetherlands
| | - R J Stokroos
- Department of Otorhinolaryngology/Head and NeckSurgery, Maastricht University Medical Centre, PO Box 5800, Maastricht, TheNetherlands
| | - S G H Litjens
- Faculty of Health, Medicine and Life Sciences, Universityof Maastricht, PO Box 616, Maastricht, The Netherlands
| | - B Kremer
- School of Oncology and Developmental Biology, Universityof Maastricht, PO Box 5800, Maastricht, The Netherlands.,Department of Otorhinolaryngology/Head and NeckSurgery, Maastricht University Medical Centre, PO Box 5800, Maastricht, TheNetherlands
| | - B W Kramer
- Department of Pediatrics, Maastricht University MedicalCentre, PO Box 5800, Maastricht, The Netherlands.,School of Oncology and Developmental Biology, Universityof Maastricht, PO Box 5800, Maastricht, The Netherlands
| |
Collapse
|
6
|
Trinidad A, Vicente J, Verdaguer JM, Daza R, García-Berrocal JR, Ramírez-Camacho R. Morphological sequence of Plastipore extrusion in experimental otitis media. Ann Otol Rhinol Laryngol 2007; 116:779-84. [PMID: 17987784 DOI: 10.1177/000348940711601010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES Plastipore prostheses are still used by many surgeons, although the functional results are controversial. The aim of this study was the morphological analysis of Plastipore material performance in the middle ear of rats, with special attention to extrusion. METHODS Twenty-four Wistar rats were given implants made of commercially available Plastipore and assigned to 3 groups: group A, with implantation in a healthy middle ear; group B, with implantation and cauterization of the nasopharyngeal orifice of the eustachian tube (hypoventilation); and group C, with implantation, cauterization of the eustachian tube, and bacterial inoculation with Pseudomonas aeruginosa. RESULTS The pathological study showed in nearly all cases the disintegration of the biomaterial. Adhesion between the biomaterial and bone could be seen in 1 rat from group C (hypoventilation and infection). In group C, the Plastipore was in contact with the tympanic membrane in 1 case and was extruding in 2 animals. Different phases of extrusion were defined. No extrusion was observed in the other groups. CONCLUSIONS The sequential stages of Plastipore extrusion are demonstrated. Infection seems to be the most important factor in Plastipore extrusion in our model.
Collapse
Affiliation(s)
- Almudena Trinidad
- Ear Research Group, Department of Otorhinolaryngology, University Hospital Puerta de Hierro, Autonomous University of Madrid, Madrid, Spain
| | | | | | | | | | | |
Collapse
|
7
|
Verdaguer JM, Trinidad A, González-García JA, García-Berrocal JR, Ramírez-Camacho R. Spontaneous otitis media in Wistar rats: an overlooked pathology in otological research. Lab Anim (NY) 2006; 35:40-4. [PMID: 17077834 DOI: 10.1038/laban1106-40] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Accepted: 09/14/2006] [Indexed: 12/20/2022]
Abstract
The rat is commonly employed in otological research, but spontaneous ear infections can confound the results of experimental procedures--wasting time, money, and animals. The authors focus on the incidence of spontaneous otitis media in Wistar rats. They compare disease incidence in animals housed in standard cages with those housed in barrier units, showing that 20% of their conventionally housed animals developed spontaneous otitis media, whereas only 5% of their animals housed in isolated units were infected. These results underscore the importance of strict control of the shipping, housing conditions, and manipulation of animals to be used in otological research.
Collapse
Affiliation(s)
- José María Verdaguer
- Department of Otorhinolaryngology, Hospital Universitario La Paz, Universidad Autónoma de Madrid, Spain.
| | | | | | | | | |
Collapse
|