Evidence of oxygen free radical damage in human otitis media

Plasma Selenium and Cadmium Levels in Patients with Chronic Otitis Media in a Turkish Population and Their Relation to Inflammation Markers

Chronic otitis media (COM) is a multifactorial process, for which a clear etiology has not yet been established. The aims of the present study were to evaluate selenium (Se) and cadmium (Cd) levels in patients with COM and to analyze the correlation between Se and Cd with inflammation markers. The study population consisted of 88 participants: 45 healthy controls (group 1) and 43 patients with COM (group 2). Demographic data, Se, Cd, C-reactive protein (CRP), and white blood cell count (WBC) levels were all recorded. Se and Cd measurements were performed in a graphite furnace atomic absorption spectrophotometer (Perkin Elmer Analyst 800) using Zeeman background correction. The Se and Cd levels were compared between the groups and the correlation between Se and Cd with inflammation markers was analyzed. No statistically significant difference was determined between the groups in terms of demographic data (p > 0.05). CRP and WBC levels were significantly higher in group 2 than in group 1 (p < 0.05). Se levels were significantly lower in group 2 than in group 1, at 23.40 ± 12.08 μg/L vs. 37.31 ± 22.44 μg/L (p < 0.05). Cd levels were significantly higher in group 2 than in group 1, at 1.79 ± 1.63 μg/L vs. 0.68 ± 0.45 μg/L (p < 0.05). When all the cases were evaluated together, a statistically significant negative correlation was determined between Se and CRP (r = - 0.239, p = 0.013) and a positive correlation between Cd and CRP (r = 0.266, p = 0.006), WBC (r = 0.258, p = 0.008). Our results could propose that Se deficiency and Cd excess could play a crucial and additive role in the etiopathogenesis of COM. However, further investigations with larger numbers of patients are warranted to determine the exact role of these elements.

Antioxidant responses and DNA damage in primary hepatocytes of Van fish (Alburnus tarichi, Güldenstadt 1814) exposed to nonylphenol or octylphenol

Alkylphenols, a nonionic surface-active agent group, such as nonylphenol (NP) and octylphenol (OP) are important endocrine-disrupting chemicals (EDC). In this study, the dose- and time-dependent effects of NP and OP were investigated in the primary hepatocyte culture of Van Fish. In this study, samples were taken at different times and biochemical parameters were studied separately. The effects of the chemicals used on SOD, CAT, GSH-Px, MDA, and 8-OHdG were investigated in hepatocyte culture. The antioxidants SOD and CAT were observed to increase in all groups in the primary hepatocyte cultures at the 24th hour after NP and OP administration, whereas the GSH-Px level was observed to increase with OP at the 24th hour and with NP at the 48th hour. The MDA level was observed to reach its highest value for both chemicals in the 24th hour, and the 8-OHdG level was observed to increase toward the end of the follow-up time, compared to the control group (p < 0.05). In conclusion, different doses of NP and OP were found to induce an increase in the levels of antioxidants and the MDA level in Van Fish primary hepatocyte culture. DNA damage, on the other hand, may be considered to appear after longer-term exposure to NP and OP.

Anti-inflammatory and anti-oxidative effects of alpha-lipoic acid in experimentally induced acute otitis media

Objectives:

To investigate the anti-inflammatory, anti-oxidative and tissue protective effects, as well as the potential therapeutic role, of alpha-lipoic acid in experimentally induced acute otitis media.

Methods:

Twenty-five guinea pigs were assigned to one of five groups: a control (non-otitis) group, and otitis-induced groups treated with saline, penicillin G, alpha-lipoic acid, or alpha-lipoic acid plus penicillin G. Tissue samples were histologically analysed, and oxidative parameters in tissue samples were measured and compared between groups.

Results:

The epithelial integrity was better preserved, and histological signs of inflammation and secretory metaplasia were decreased, in all groups compared to the saline treated otitis group. In the alpha-lipoic acid plus penicillin G treated otitis group, epithelial integrity was well preserved and histological findings of inflammation were significantly decreased compared to the saline, penicillin G and alpha-lipoic acid treated otitis groups. The most favourable oxidative parameters were observed in the control group, followed by the alpha-lipoic acid plus penicillin G treated otitis group.

Conclusion:

Alpha-lipoic acid, with its antioxidant, anti-inflammatory and tissue protective properties, may decrease the clinical sequelae and morbidity associated with acute otitis media.

Serum paraoxonase and arylesterase activities in patients with chronic otitis media

OBJECTIVES

Paraoxonase-1 (PON1) prevents oxidative stress by inhibiting the oxidation of cell membrane lipids by the reactive oxygen species that form during acute and chronic inflammation. The aim of this study was to investigate serum PON1 activity and oxidative stress in patients with chronic otitis media (COM).

METHODS

Fifty consecutive patients with COM and 55 controls were enrolled in the present study. The patients were divided into two groups according to the presence of cholesteatoma. The serum PON1 arylesterase activities and lipid hydroperoxide (LOOH) levels were determined.

RESULTS

Serum paraoxonase and arylesterase activities were significantly lower in the COM patients than in the controls (P < 0.001 for all comparisons), whereas the LOOH levels were significantly higher (P < 0.001).

DISCUSSION

These results indicated that a lower level of PON1 activity was associated with an oxidant-antioxidant imbalance. In addition, decreased PON1 activity may play an important role in the pathophysiology of COM.

Advanced oxidation protein product level in children with chronic otitis media with effusion

OBJECTIVE

To determine the level of advanced oxidation protein products (AOPPs) in children with chronic otitis media with effusion (COME), in an effort to elucidate the multifactorial etiology of this disease.

METHODS

This study involved 25 COME patients and 30 healthy children (control group) recruited from the Ear, Nose and Throat (ENT) and Pediatric Departments, respectively, of the Haseki Research and Training Hospital. In the COME group, blood samples were collected before a middle ear operation, and middle ear fluid was sampled during the operation. Blood samples were also obtained from the control subjects. AOPP levels in the plasma and effusion fluid were measured by the spectrophotometric method.

RESULTS

In the COME group, the mean AOPP levels in plasma and effusion fluid were 168.08 μmol/l and 412.75 μmol/l, respectively. In the control group, the mean plasma AOPP level was 141.54 μmol/l. The plasma AOPP levels did not significantly differ between the COME and control groups (p>0.05). In the COME group, however, the effusion fluid AOPP level (412.75 ± 204.54 μmol/l) was significantly higher than the plasma AOPP level (168.08 ± 68.45 μmol/l; p<0.01).

CONCLUSION

We found that AOPP levels were elevated in the effusion fluid, but not in the plasma, of COME patients. Thus, COME was associated with protein oxidation abnormalities. Oxidative stress may play a role in the etiopathogenesis of COME, and AOPPs may be used as markers of oxidative stress; however, further studies are required to confirm these findings.

Serum myeloperoxidase activity, total antioxidant capacity and nitric oxide levels in patients with chronic otitis media

It has been suggested that oxidative stress may play an important role in the pathogenesis of chronic otitis media (COM), but the role of oxidative stress in the pathogenesis of COM has not yet been fully explored. Therefore, the aim of this study was to investigate serum myeloperoxidase (MPO) activity, 4-hydroxynonenal (4-HNE), malondialdehyde (MDA), total antioxidant capacity (TAC) and nitric oxide (NO) in patients with COM. Sixty-one patients with COM and 30 controls were enrolled in the present study. Patients were divided into two groups according to the presence (n = 21) or absence (n = 40) of cholesteatoma. Serum MPO activity and 4-HNE, MDA and NO levels were significantly higher in patients with COM than controls (for all, p < 0.001), while TAC levels were significantly lower (for all, p < 0.001). Serum MPO activity and MDA, 4-HNE and NO levels were significantly higher in patients with cholesteatoma than in those without cholesteatoma, while TAC levels were significantly lower; but the difference between groups was not statistically significant (p > 0.05). Increased oxidative stress seems to be associated with decreased antioxidant levels in patients with COM. Thus, increased oxidative stress may play a role in the pathogenesis of COM. It is believed that the administration of antioxidant vitamins such as A, C and E may be useful in preventing and treating COM.

Oxidative stress in chronic otitis media with effusion

CONCLUSIONS

The high oxidant levels in chronic otitis media with effusion (OME) observed in our research and the improvement seen in children with chronic OME after antioxidant treatment suggest that oxygen-derived free radicals play an important role in chronic OME.

OBJECTIVES

OME is a common pathologic condition characterized by nonpurulent fluid in the middle ear (ME) that leads to moderate conductive hearing loss and flat tympanogram. During OME inflammatory cells generate large amounts of superoxide radicals to improve bactericidal activity. Overproduction of oxygen-derived free radicals induces oxidative damage in humans. Glutathione (GSH) is one of the major components of the antioxidant system that protects cells from oxidative stress. The aim of the study was to evaluate oxidative stress in chronic OME by investigation of ME fluids collected during myringotomy.

METHODS

During myringotomy, fluid was collected from the ME to evaluate lipid peroxide levels in the effusion. Fifty-nine children with ME effusion without any resolution after repeated medical treatments were enrolled in the study.

RESULTS

Lipid peroxide levels in all samples were high (mean 11.5 nmole/million cells), similar to the values found in other chronic diseases. GSH might be employed during surgery while applying ventilation tubes and after surgery to prevent oxidative stress.

Antioxidant role of selenium in rats with experimental acute otitis media

The aim of this prospective experimental animal study was to determine whether selenium had a protective effect on oxidative stress in rats with acute otitis media, by measuring the alterations of antioxidant parameters and lipid peroxidation on days 4 and 10 after inoculation into the middle ear. Streptococcus pneumoniae was inoculated into the middle ear cavities of 32 rats in animal laboratory of a tertiary medical center. Group 1 served as the control group and the animals were administered 1.5 ml/day saline. Group 2 received 0.2 mg/kg/day oral selenium for 10 days. The blood samples of each group were obtained on post-inoculation days 4 and 10. The levels of thiobarbituric acid reactive substances, albumin, total sulphydryl, superoxide dismutase and glutathione peroxidase were investigated. Day 10 level of thiobarbituric acid reactive substance in group 2 was lower than the day 4 level of the same substance in the control group. Although glutathione peroxidase and superoxide dismutase levels significantly decreased starting from 4th day until 10th day in group 1, their levels increased in group 2. Day 10 levels of albumin and total sulphydryl in group 1 were significantly higher than day 4 levels in group 2. We found that selenium supplementation for 10 days decreased thiobarbituric acid reactive substances and increased glutathione peroxidase and superoxide dismutase levels when compared to the control group. We believe that selenium supplementation may be beneficial to prevent the clinical sequelae and recurrence of otitis media.

The role of inflammatory mediators in the pathogenesis of otitis media and sequelae

This review deals with the characteristics of various inflammatory mediators identified in the middle ear during otitis media and in cholesteatoma. The role of each inflammatory mediator in the pathogenesis of otitis media and cholesteatoma has been discussed. Further, the relation of each inflammatory mediator to the pathophysiology of the middle and inner ear along with its mechanisms of pathological change has been described. The mechanisms of hearing loss including sensorineural hearing loss (SNHL) as a sequela of otitis media are also discussed. The passage of inflammatory mediators through the round window membrane into the scala tympani is indicated. In an experimental animal model, an application of cytokines and lipopolysaccharide (LPS), a bacterial toxin, on the round window membrane induced sensorineural hearing loss as identified through auditory brainstem response threshold shifts. An increase in permeability of the blood-labyrinth barrier (BLB) was observed following application of these inflammatory mediators and LPS. The leakage of the blood components into the lateral wall of the cochlea through an increase in BLB permeability appears to be related to the sensorineural hearing loss by hindering K⁺ recycling through the lateral wall disrupting the ion homeostasis of the endolymph. Further studies on the roles of various inflammatory mediators and bacterial toxins in inducing the sensorineumral hearing loss in otitis media should be pursued.

The role of free oxygen radicals on the development of otitis media with effusion

OBJECTIVE

The purpose of this study was to determine if free oxygen radicals (FORs) and antioxidant enzyme activities have some role in pathogenesis of otitis media with effusion (OME) in children with adenoid hyperplasia.

METHODS

Seventy-four patients were enrolled in three groups of this study. The study group (Group I) included 26 patients who had adenoidectomy with ventilation tube placement due to chronic OME. The control adenoid group (Group II) consisted of 28 age-matched patients who had adenoidectomy without ventilation tube insertion. Twenty children were included in the healthy control group (Group III). Erythrocyte malondialdehyde (MDA) levels, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) enzyme activities were investigated in the venous blood sample.

RESULTS

Erythrocyte MDA level and GSH-Px enzyme activity in the blood samples of study group (Group I) were significantly higher than those of Group II and Group III (P < 0.05). SOD enzyme activity in the blood samples of Group I was significantly lower than Group II (P < 0.05), and were significantly higher than Group III (P < 0.05). CAT enzyme activity of Group I was significantly lower than that of Group III (P < 0.05). However, there was no statistically significant difference between Group I and Group II regarding CAT antioxidant enzyme activity (P < 0.05).

CONCLUSIONS

The inflammation of the middle ear increases the level of FORs in erythrocyte. FOR level is normally maintained at a steady state by antioxidant enzymes. When the antioxidant defense system is weakened, the increased FORs may contribute to OME formation. We supposed that, antioxidant vitamins C and E, and scavenger enzymes such as CAT, SOD and GSH-Px may be added in the management of OME.

Production of nitric oxide by the middle ear epithelium and subsequent inhibition of sodium transport

The production of nitric oxide (NO) within the middle ear has not previously been characterized. The presence of NO synthase (NOS) transcripts was demonstrated using RNA amplification by reverse transcriptase-polymerase chain reaction in rat middle ear mucosa and in rat primary cultured middle ear epithelial cells. The expression of NOS was indirectly assessed by nitrite measurement in the supernatant of primary cultured cells. The effect of NO on ion transport was investigated in a previously described middle ear epithelial cell line using the short-circuit current (Isc) technique. NO per se had no effect on Isc. However, previous work has shown that sodium transport is stimulated by reactive oxygen species (ROS). NO blunted this stimulation, an inhibition probably related to the toxicity of peroxynitrite, ONOO-, a highly reactive compound. These results suggest that NO is produced by middle ear epithelial cells and that, in the presence of ROS, NO may be responsible for an inhibition of ion transport viaperoxynitrite formation.