Can apelin play a role in the etiology of tinnitus?

Abstract

Background/aim: Tinnitus is seen in 15% of the general population; in 1%–6% of this number, the quality of life is seriously affectedby this chronic condition. Chemical, oxidative, and emotional stressors are important in terms of the clinical course of tinnitus. Apelinis an endogenous peptide which is an oxidative stress mediator. It has been shown that the apelin/APJ (apelin junction receptor) systemplays various roles in the physiology and pathophysiology of many organs. However, the role of the apelin/APJ system as an oxidativestress mediator in tinnitus is unknown. We investigated the level of apelin in patients with normal hearing and bilateral tinnitus.Materials and methods: We enrolled patients diagnosed with bilateral idiopathic tinnitus. Tinnitus severity was determined using thetinnitus handicap inventory (THI). We recorded the levels of plasma apelin-13 and biochemical parameters.Results: The mean apelin level of the control group was higher than that of the patient group (P = 0.002). A significant negativecorrelation was evident between the apelin level and the THI (r = –0.460, P = 0.003). The triglyceride (TG) level was significantly higherin the patient group than in the control group (P < 0.001).Conclusions: In our study, we found a negative correlation between apelin and tinnitus severity. Thus, apelin may play a role in thepathophysiology of idiopathic tinnitus, and may be prescribed during follow-up to reduce oxidative stress in the future. Further clinicalstudies on the effects of the apelin/APJ (apelin junction receptor) system and the effects of antioxidants in patients with inflammatorydiseases are required.