Neutrophil-mediated immune response as a possible mechanism of acute unilateral vestibulopathy

Clinical Significance of Neutrophil-to-Lymphocyte Ratio and Platelet-to-Lymphocyte Ratio in Acute Unilateral Vestibulopathy

BACKGROUND AND PURPOSE

The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been identified as useful biomarkers for assessing the inflammatory response and for predicting the prognosis of various diseases. This study aimed to determine the clinical significance and effects on prognostic prediction of NLR and PLR in acute unilateral vestibulopathy (AUV).

METHODS

We retrospectively recruited 128 patients who were diagnosed with AUV from July 2016 to April 2021, and compared NLR and PLR values between these patients with AUV and age- and sex-matched healthy subjects. We also analyzed the correlations of various clinical parameters with NLR and PLR.

RESULTS

NLR and PLR in the AUV group were 3.41±2.80 (mean±standard deviation) and 128.86±67.06, respectively, with only NLR being significantly higher than that in the control group (1.55±0.60, p<0.001). The gain asymmetry of the horizontal vestibulo-ocular reflex (VOR) was slightly larger in patients with high NLR (n=52) than in those with normal NLR (n=76) (41.9%±20.2% vs. 33.6%±17.4%, p=0.048). However, the hospitalization period, preceding infection, canal paresis, and absolute horizontal VOR gain did not differ between patients with high and normal NLR and PLR values. The correlation analyses also revealed that none of the clinical parameters were significantly correlated with NLR or PLR. At 3-month follow-up examinations, NLR and PLR did not differ significantly between patients with and without function recovery of the horizontal VOR.

CONCLUSIONS

This study found a high NLR in AUV, suggesting an acute inflammatory status in the vestibular organ. However, the usefulness of NLR and PLR as prognostic markers remains unclear.

Vestibular function is associated with immune inflammatory response

Association between vestibular function and immune inflammatory response has garnered increasing interest. Immune responses can lead to anatomical or functional alterations of the vestibular system, and inflammatory reactions may impair hearing and balance. Vestibular disorders comprise a variety of conditions, such as vestibular neuritis, benign paroxysmal positional vertigo, Meniere's disease, vestibular migraine, posterior circulation ischemia, and bilateral vestibular disease. Moreover, some patients with autoimmune diseases develop vestibulocochlear symptom. This paper offers an overview of prevalent vestibular diseases and discusses associations between vestibular dysfunction and immune diseases.

Pharmacological Treatment of Acute Unilateral Vestibulopathy: A Review

There have been few investigations on the epidemiology, etiology, and medical management of acute unilateral vestibulopathy (AUV). Short-term pharmaceutical resolutions include vestibular symptomatic suppressants, anti-emetics, and some cause-based therapies. Anticholinergics, phenothiazines, antihistamines, antidopaminergics, benzodiazepines, and calcium channel antagonists are examples of vestibular suppressants. Some of these medications may show their effects through multiple mechanisms. In contrast, N-acetyl-L-leucine, Ginkgo biloba, and betahistine improve central vestibular compensation. Currently, AUV pathophysiology is poorly understood. Diverse hypotheses have previously been identified which have brought about some causal treatments presently used. According to some publications, acute administration of anti-inflammatory medications may have a deleterious impact on both post-lesional functional recovery and endogenous adaptive plasticity processes. Thus, some authors do not recommend the use of corticosteroids in AUV. Antivirals are even more contentious in the context of AUV treatment. Although vascular theories have been presented, no verified investigations employing anti-clotting or vasodilator medications have been conducted. There are no standardized treatment protocols for AUV to date, and the pharmacological treatment of AUV is still questionable. This review addresses the most current developments and controversies in AUV medical treatment.

Clinical Features and Neurotologic Findings in Patients With Acute Unilateral Peripheral Vestibulopathy Associated With Antiganglioside Antibody

BACKGROUND AND OBJECTIVES

Anecdotal studies have reported the presence of antiganglioside antibodies in acute unilateral peripheral vestibulopathy (AUPV). This study aimed to determine the prevalence, clinical characteristics, and neurotologic findings of AUPV associated with antiganglioside antibodies.

METHODS

Serum antigangliosides were measured in consecutive patients with AUPV according to the Bárány Society criteria during the acute and recovery phases in a referral-based university hospital in South Korea from September 2019 to January 2023. Clinical characteristics and neurotologic findings were compared between those with and without antiganglioside antibodies. The results of video-oculography, video head impulse and bithermal caloric tests, and other neurotologic evaluations including ocular and cervical vestibular-evoked myogenic potentials and subjective visual vertical were compared between the 2. MRIs dedicated to the inner ear were also conducted when considered necessary.

RESULTS

One hundred five patients (mean age ± SD = 60 ± 13 years, 57 male) were included for analyses. During the acute phase, 12 patients (12/105, 11%) were tested positive for serum antiganglioside antibodies, including anti-GQ1b immunoglobulin (Ig) G (n = 5) or IgM (n = 4), anti-GM1 IgM (n = 3), and anti-GD1a IgG (n = 1, including 1 patient with a positive anti-GQ1b antibody). Patients with antiganglioside antibodies showed lesser intensity of spontaneous nystagmus (median [interquartile range] = 1.8 [1.2-2.1] vs 3.4 [1.5-9.5], p = 0.003) and a lesser degree of canal paresis (30 [17-47] vs 58 [34-79], p = 0.028) and gain asymmetry of the vestibulo-ocular reflex for the horizontal semicircular canal during head impulse tests (0.07 [-0.04 to 0.61] vs 0.36 [0.18-0.47], p = 0.032) than those without antibodies. Negative conversion of antibodies and vestibular recovery were observed in most patients (6/8, 75%). Among 30 patients with AUPV with 4-hour delayed 3D fluid-attenuated inversion recovery dedicated to the inner ear, gadolinium enhancement was observed in 18 (18/30, 60%), either in the vestibule (n = 9), semicircular canal (n = 6), or vestibular nerve (n = 5). The positivity rates based on specific antibodies could not be determined due to limited sample sizes.

DISCUSSION

The association between antiganglioside antibodies and AUPV suggests an immune-mediated mechanism in acute vestibular failure and extends the clinical spectrum of antiganglioside antibody syndrome.

Gene expression analysis in recurrent benign paroxysmal positional vertigo: a preliminary study

Objectives

This study aimed to determine the pathophysiology of recurrent benign paroxysmal positional vertigo (BPPV) in young patients using gene expression profiling combined with bioinformatics analysis.

Methods

Total RNA was extracted from the whole blood of four young patients with recurrent BPPV and four controls. The differentially expressed genes (DEGs) between the groups were screened using a microarray analysis based on the cutoff criteria of |log₂ fold change| > 1 and an adjusted p-value of < 0.05. Functional enrichment analysis of DEGs was performed using Gene Ontology analysis, and the protein-protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of the Interacting Genes database.

Results

A total of 39 DEGs were detected between the BPPV and control samples, comprising 33 upregulated DEGs and six downregulated DEGs in the BPPV group. Functional enrichment analysis indicated that the upregulated DEGs were significantly enriched in terms related to metabolic processes and the immune system. Two main pathways were extracted from the PPI network: one was associated with oxidative phosphorylation and stress and the other with the adaptive immune system and extracellular matrix degradation.

Conclusion

The findings of our bioinformatics analysis indicated that oxidative stress or extracellular matrix degradation due to immune-mediated inflammatory responses may contribute to the development of recurrent BPPV in young patients.

Identification of hub genes and pathophysiological mechanism related to acute unilateral vestibulopathy by integrated bioinformatics analysis

Background

Although many pathological mechanisms and etiological hypotheses of acute unilateral vestibulopathy (AUVP) have been reported, but the actual etiology remains to be elucidated.

Objective

This study was based on comprehensive bioinformatics to identify the critical genes of AUVP and explore its pathological mechanism.

Methods

Gene expression profiles of AUVP and normal samples were collected from GSE146230 datasets of the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) was constructed, and the WGCNA R-package extracted significant modules. The limma R-package was applied to identify differentially expressed genes (DEGs). The common genes of practical modules and DEGs were screened for GO and KEGG pathways analysis. The protein–protein interaction (PPI) layout and hub genes validation was created by Cytoscape software using the link from the STRING database. The functions of hub genes were predicted through the CTD (comparative genetics database).

Results

A total of 332 common genes were screened from practical modules and DEGs. Functional enrichment analysis revealed that these genes were predominantly associated with inflammation and infection. After construction of PPI, expressions of hub genes, and drawing ROC curves, LILRB2, FPR1, AQP9, and LILRA1 are highly expressed in AUVP (p < 0.05) and have a certain diagnostic efficacy for AUVP (AUC > 0.7), so they were selected as hub genes. The functions of hub genes suggested that the occurrence of AUVP may be related to inflammation, necrosis, hepatomegaly, and other conditions in CTD.

Conclusion

LILRB2, FPR1, AQP9, and LILRA1 may play essential roles in developing AUVP, providing new ideas for diagnosing and treating AUVP.

[Serum 25-hydroxyvitamin D expression and its correlation in patients with vestibular neuritis]

Objective:To investigate the expression level of serum 25-（OH） D and its correlation in patients with vestibular neuritis（VN）. Methods:30 acute VN patients and 50 age-and sex-matched healthy controls who attended the Otolaryngology, Head and Neck Surgery Department of the First Hospital of Shanxi Medical University from October 2020 to October 2021 were selected. The demographic and clinical data of all subjects were recorded, the levels of serum 25-（OH） D and inflammatory markers were measured and compared, and the changes of serum 25-（OH） D levels in convalescent patients with VN were followed up. Results:The serum level of 25-（OH） D in the acute phase VN group was significantly lower than that in healthy controls[（10.14±2.92） ng/mL vs （20.61±4.70） ng/mL, P<0.01], and the deficiency rate of 100.0%（30/30） was significantly higher than 54.0%（27/50）. Moreover, the serum level of 25-（OH） D in the recovery period（3 months later） was significantly higher[（10.14±2.92） ng/mL vs （15.94±4.88） ng/mL, P<0.01], and the deficiency rate was significantly decreased by 76.7%（23/30）. However, the serum 25-（OH） D level was significantly lower in both the VN group than that in both the acute period and the recovery group, and the deficiency rate was significantly higher than that in the control group. Multivariate binary Logistic regression model analysis showed that low-level serum 25-（OH） D was associated with the onset of VN, with an OR value of 0.193（95%CI=0.043-0.861, P=0.031）. In addition, the results of this study showed that peripheral blood leukocyte（WBC） and neutrophil / lymphocyte ratio（NLR） levels in the acute VN group were significantly higher than in healthy controls[（7.65±3.02） ×10⁸/L vs （5.50±2.50） ×10⁸/L, P<0.01; （2.46±2.95） ×100% vs（1.67±0.92） ×100%, P<0.01 ], and there was no significant difference in Platelet / lymphocyte ratio（PLR） and and average platelet volume（MPV） levels in the two groups（P>0.05）. There were no significant differences in age distribution, sex ratio, body mass index, persistent health problems, or lifestyle groups（P>0.05）. Conclusion:This study is the first to detect serum 25-（OH） D level and inflammation index level, and dynamically assess the serum 25-（OH） D level in different stages, found that low serum 25-（OH） D is associated with the onset of VN, physiological concentration of serum 25-（OH） D is a protective factor of VN, vitamin D supplementation therapy may be a new target of VN treatment.

Transcriptional Down-Regulation of Major Histocompatibility Complex as a Possible Pathogenesis for Meniere's Disease

Objectives

This study aimed to determine the underlying pathogenesis of Meniere's disease (MD) using transcriptome analysis.

Methods

Total RNA was extracted from the peripheral blood mononuclear cells of 39 patients with MD and 39 controls. Through microarray analysis for nine patients and controls, the differentially expressed genes (DEGs) of those two groups were screened based on cut-off criteria (|fold changes| > 2.0 and adjusted p-value < 0.05). The functional enrichment analysis of DEGs was performed using Gene Ontology (GO).

Results

There were 996 DEGs identified in the MD group: 415 were upregulated and 581 were downregulated. A functional enrichment analysis indicated that the downregulated DEGs were significantly enriched in terms related to immune system processes. Among them, 17 genes were enriched in terms for the major histocompatibility complex (MHC) protein complex, and the relative messenger RNA (mRNA) levels of three markedly downregulated DEGs [fold changes < −5: human leukocyte antigen (HLA)-DMA, HLA-DRB1, and HLA-DPB1] were significantly decreased in another 30 patients with MD compared with normal controls by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). However, there were no correlations between the expression levels of these three genes and clinical data, such as age, onset age, time course, or hearing threshold.

Conclusions

Our transcriptome analysis showed that the downregulated DEGs in MD were mainly associated with the immune system pathways including the MHC protein complex in MD. Remarkably, a breakdown in immunological tolerance mediated by MHC class II may contribute to the MD development, which has implications for targeted treatment.

Vascular mechanisms in acute unilateral peripheral vestibulopathy: a systematic review

Acute unilateral peripheral vestibulopathy (AUPVP) is a frequent cause of vestibular loss. Several aetiologies have been proposed, but the exact mechanism remains unknown. The aim of this study is a systematic analysis of the literature evaluating the vascular aetiology of AUPVP. A systematic literature search was performed in PubMed, Cochrane Library and Embase, including articles published from January 1^st, 2010 to November 30^th, 2020. Two reviewers independently selected articles investigating a link between AUPVP and vascular disease. The following information was extracted: year of publication, country, level of evidence, assessed vascular risk factors and number of patients. A total of 450 articles was obtained. Eleven articles were retained with 100% agreement between the two reviewers. In a pooled population of 805 patients, the main results were the higher neutrophil to lymphocyte ratio and higher prevalence of vascular risk factors among AUPVP patients. A meta-analysis was not performed because the studies were too heterogeneous in terms of methodology. Indirect arguments for vascular mechanisms in AUPVP were found. These findings indicate that larger prospective well-controlled studies are needed to clarify the vascular aetiology of AUPVP.