1.Research Summary

Department of Otolaryngology - Head and Neck Surgery carries out highly-qualified research in the broad field of otolaryngology, head and neck surgeries. We have many collaborating projects with other departments in Niigata University including brain research institute, departments of molecular physiology, neuroanatomy, molecular and cellular pathology, and psychiatry.

2.Research Groups

• Vestibular and Auditory Research Group
• Nasal and Laryngo-Pharyngeal Research Group
• Head and Neck Oncology Research Group

3-1.Vestibular and Auditory Research

Persistent Postural Perceptual Dizziness (PPPD)
Prof. Horii is acting as a subcommittee member of International Classification of Vestibular Disorders (ICVD) of Barany Society, the world-wide biggest society for vestibular science. This subcommittee recently proposed a definition of chronic functional dizziness named Persistent Postural Perceptual Dizziness (PPPD). PPPD patients have persistent dizziness or unsteadiness lasting for more than six months and the symptoms are exacerbated by upright position, active or passive movement and exposure to moving or complex visual stimuli. Our group is conducting research on PPPD from the basic level using rat animal models to the clinical research aiming to develop new diagnosing modality and treatment of PPPD.
Clarification of pathology of otitis media with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (OMAAV)
The antineutrophil cytoplasmic antibody (ANCA) against neutrophil lysosomal enzymes such as myeloperoxidase (MPO) and proteinase 3 (PR3) releases lytic enzymes that cause vascular inflammation; this leads to systemic vasculitis known as ANCA-associated vasculitis (AAV). These ANCA-associated diseases may involve organs throughout the body, such as the eye, nose, ear, lung, and kidney. Recently, the occurrence of otologic symptoms such as otitis media and hearing loss frequently have been reported in patients with AAV. These cases are difficult to diagnose at the early stage and OMAAV may cause some permanent dysfunction such as severe hearing loss. Japan otological society organized the OMAAV working group for clarification of OMAAV pathology. Dr. Morita is a member of this working group and contributes to the accumulation of the OMAAV patients to establish the appropriate treatment and follow-up methods.

Middle ear cholesteatoma
Middle ear cholesteatoma is a challenging condition due to its progressive and destructive characteristics. Until recently, there was no staging system of cholesteatoma that are parallel to treatment outcome. In 2010, the Japan Otological Society (JOS) proposed JOS staging system for middle ear cholesteatoma (2010), and it became widely used in Japan. As a member of the Japan Otological Society Terminology Committee, Dr. Morita has cooperated with constructing the database of cholesteatoma in nation-wide and writing the draft of staging system and its revision at 2015. At 2017, European Academy of Otology and Neurotology (EAONO) also proposed the staging system of cholesteatoma, which was basically the same staging system by JOS. Based on these databases, the validity and utility of this staging system is being verified by multicenter clinical trials. In addition, we are conducting research how to select the appropriate surgical method for each individual.

3-2.Nasal and Laryngo-Pharyngeal Research

Pathophysiological mechanisms of globus sensation of throat: involvement of gastro-esophageal reflex and anxiety disorder
The globus sensation is defined that the patient has a persistent sensation of having a lump in the throat with no detectable physical cause. Recently, the number of globus patients is increasing, which is around 5-10% of patients in ENT outpatient clinic. The most plausible theory of globus sensation is that it is caused by the gastro-esophageal reflex of gastric acids. However, some cases are refractory to proton pump inhibitor (PPI) treatment. As other characteristics of the globus sensation patients, they are sometimes anxious and depressive for whom anti-anxious medicine is partly effective in relieving the symptoms. Therefore, globus sensation may be multifactorial disease.
In this project, we translated the current most useful questionnaire to evaluate the subjective symptoms of the globus sensation, namely Glasgow-Edinburgh Throat Scale (GETS), into the Japanese for the first time and are now validating the Japanese version. The second purpose of this project is to construct a diagnosing algorithm of the globus sensation based on the gastro-esophageal reflux (GER) testing (upper gastro-intestinal endoscopy, pH monitoring, esophageal manometry) and psychiatric assessment using the Hospital Anxiety and Depression Scale (HADS) questionnaire. The ultimate purpose of this project is to build up the tailor-made treatment system for globus sensation in combination with the diagnosing test battery.

Olfactory function test as a tool for early detection of Alzheimer’s disease
In Japan, the elderly population aged 65 years or over exceeds 1/4 of the total population for the first time in 2013, and the prevalence of dementia is estimated to exceed 10%. Alzheimer's disease (AD) is the most frequent cause of dementia accounting for 40 to 60% of all dementia. Because of its irreversible and progressive characteristics, early detection and prompt start of treatment is important. For this purpose, an early diagnosing battery for AD is expected.
Brain atrophy of AD begins from the medial temporal lobe (MTL) including the primary olfactory area, and therefore, olfactory dysfunction is one of the initial symptoms of AD. In addition, as initial MTL atrophy is unilateral, there is a possibility that the olfactory dysfunction is also unilateral at the early stage of AD. In this study, we elucidate the relationship between the olfactory disorder and the right-left difference of MTL atrophy in early AD and examine whether olfactometry can be a new biomarker in early detection of AD.

3-3.Head and Neck Oncological Research

Our group have conducted several multicenter studies in Niigata Prefecture, which analyzed the safety and tolerance of concomitant chemoradiotherapy with high dose cisplatin, and utility of swallowing exercise for head and neck cancer of disability.
We have also performed basic research in cooperation with molecular pathology department, division of gastroenterology, and pathological department. Our molecular research is focused on cancer microenvironment (tumor stroma, hypoxia or cytokines, etc.). We have identified some protein hydroxylases, which are known to be involved in hypoxic response, as the targets for novel anti-cancer therapy. We are doing pathological analysis about the superficial laryngopharyngeal carcinoma with division of gastroenterology and the pathological department. The superficial laryngopharyngeal carcinoma is determined that its extension is limited in mucosal or submucosal layer. Its prognosis is an excellent, but approximately 5% of cases cause cervical lymph node metastasis. We are analyzing pathological features and endoscopic findings, which are related to metastasis, to contribute to more precisional therapy.

Please see the Otolaryngology-Head and Neck Surgery website for a detailed description of our research.