Human herpesvirus-6 and -7 DNA in cerebrospinal fluid of facial palsy patients

Cox4i2 Triggers an Increase in Reactive Oxygen Species, Leading to Ferroptosis and Apoptosis in HHV7 Infected Schwann Cells

Emerging evidence suggests that reactive oxygen species (ROS) play a significant role in the pathogenesis of peripheral nerve damage. Our previous study indicated that human herpesvirus 7 (HHV7) induces Bell’s palsy. However, the specific mechanism underlying the effects of ROS in HHV7 infection-induced facial nerve damage is unknown. In this study, we established a rat FN model by inoculating an HHV7 virus solution. The facial grading score and LuxolFastBlue (LFB) staining were used to assess the success of the model. Using mRNA-sequencing analysis, we found that the expression of Complex IV Subunit 4 Isoform 2 (Cox4i2) increased in infected Schwann cells (SCs). Cox4i2 was suggested to increase COX activity, thereby promoting ROS production. The changes in the endogenous oxidant and antioxidant system were assessed, and the results showed that oxidative stress increased after HHV7 infection in vivo and in vitro. However, we found that oxidative injury was relieved after the transfection of shCox4i2 in HHV7-treated SCs by evaluating cell death, cell proliferation, and the ROS level as well as the levels of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH). Furthermore, we hypothesised that Cox4i2 loss would attenuate HHV7-induced ferroptosis and apoptosis, which are closely related to ROS in SCs. Our research illustrated that the knockdown of Cox4i2 suppresses HHV7-induced RSC96 cell ferroptosis as well as apoptosis via the ERK signalling pathway. Overall, several in vitro and in vivo methods were adopted in this study to reveal the new mechanism of ROS-induced and Cox4i2-mediated apoptosis and ferroptosis in HHV7 infected SCs.

Rare Diseases of the Salivary Glands and of Facial Nerve

Salivary gland diseases are rare. In the European Union (EU) a disease is considered to be rare if not more than 5 of 10,000 people are affected by it. According to estimates in Germany are about 4 million people with a rare disease. In the EU are about 30 million people with rare diseases [1]. In the present work most of the described diseases of salivary glands and of the facial nerve fall in this category. They form a very heterogeneous group whose treatment takes place mainly in specialized centers. Still, it is essential for the otolaryngologist to identify and to diagnose these diseases in order to initiate the right therapeutic steps. The work is a compilation of innate andacquired rare salivary gland disorders and of rare facial nerve disorders. The etiologies of inflammatory diseases, autoimmune disorders and tumors are taken into account. For the individual topics, the current literature, if available, was evaluated and turned into summarized facts. In this context the development of new processes, diagnostics, imaging and therapy are considered. Genetic backgrounds of salivary gland tumors and the trends in the treatment of tumorous lesions of the facial nerve are picked up. Furthermore, also rare diseases of the salivary glands in childhood are described. Some of them can occur in adults as well, but differ in frequency and symptoms. Due to the rarity of these diseases, it is recommended to tread these in centers with special expertise for it. Finally, the difficulties of initiation of studies and the problems of establishing disease registries concerning salivary gland disorders are discussed. This is very relevant because these pathologies are comparatively seldom.

Infectious causes of peripheral facial nerve palsy in children-a retrospective cohort study with long-term follow-up

The aim of this study was to analyze the clinical and laboratory characteristics of children with peripheral facial nerve palsy (pFP) with a focus on identifying infectious etiology and long-term outcome. We conducted an ICD-10-based retrospective chart review on children hospitalized with pFP between January 1, 2006, and December 31, 2016. Furthermore, a telephone-based follow-up survey was performed. A total of 158 patients were identified, with a median age of 10.9 years (interquartile range 6.4-13.7). An infectious disease was associated with pFP in 82 patients (51.9%); 73 cases were classified as idiopathic pFP (46.2%). Three cases occurred postoperatively or due to a peripheral tumor. Among the infectious diseases, we identified 33 cases of neuroborreliosis and 12 viral infections of the central nervous system (CNS), caused by the varicella-zoster virus, human herpesvirus 6, herpes simplex virus, enterovirus, and Epstein-Barr virus. Other infections were mainly respiratory tract infections (RTIs; 37 cases). Children with an associated CNS infection had more often headache and nuchal rigidity, a higher cerebrospinal fluid cell count, and a longer length of hospital stay. Long-term follow-up revealed an associated lower risk of relapse in CNS infection-associated pFP. Among all groups, permanent sequelae were associated with female sex, a shorter length of hospitalization, and a lower white blood cell count at presentation. pFP is frequently caused by an CNS infection or is associated with concurrent RTIs, with a potential impact on the short- and long-term clinical course.

Facial nerve palsy secondary to Epstein-Barr virus infection of the middle ear in pediatric population may be more common than we think

BACKGROUND

Facial nerve palsy is a rare complication of acute otitis media (AOM). The general understanding is that this complication has a bacterial cause although bacteria can be isolated from the middle ear only in approximately two-thirds of cases of AOM. Detection of viral agents from specimens obtained during myringotomy in patients with AOM suggests a possible role of viruses in the etiology of this disease.

CASE PRESENTATIONS

We studied 5 otherwise healthy 17- to 27-month-old children who were referred to the Department of Otorhinolaryngology and Cervicofacial Surgery from December 2012 to January 2016 because of AOM and ipsilateral facial nerve palsy. In all cases, serological tests were indicative of a primary Epstein-Barr virus (EBV) infection and no other causative pathogens were identified during hospitalization. In one patient, the technique of in situ hybridization (ISH) detected EBV-specific ribonucleic acid (RNA) sequences within tissue sections obtained during mastoidectomy.

CONCLUSIONS

The aim of this article is to alert clinicians that AOM induced facial nerve palsy secondary to an acute EBV infection in the pediatric population is very likely more common than originally thought. To our knowledge until the present case series, only 2 cases of AOM induced facial nerve palsy secondary to an acute EBV infection have been reported and no cases of EBV infection proven by the ISH technique showing the presence of EBV-specific RNA sequences in patient's tissue biopsies have been reported until now.

Meningoradiculopathy Associated with Human Herpesvirus 7-A Virus with Potential to Cause Severe Neurologic Disease with Sequelae

We present a case report of a meningoradiculopathy associated with human herpesvirus 7, with long-term motor neurologic sequelae. It is important to consider human herpesvirus 7 as a potential pathogen of severe neurologic disease and sequelae in immunocompetent children, especially in older patients presenting neurologic signs.

Clinical application of viral cerebrospinal fluid PCR testing for diagnosis of central nervous system disorders: a retrospective 11-year experience

The cerebrospinal fluid (CSF) polymerase chain reaction (PCR) is the gold standard to detect cerebral viral activity. As positive findings do not prove an impact on the neurological disorder, data interpretation is difficult. To better assess the impact of positive CSF PCR findings in different neurological diseases and to identify coherences facilitating CSF PCR data interpretation, we performed this retrospective analysis of CSF PCR data of 481 pediatric and 2604 adult patients, including herpes simplex virus (HSV), varicella zoster virus (VZV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpesvirus 6 (HHV-6), and enteroviruses (EV). Nucleic acid of EBV was detected in 1.6% (39/2449), of VZV in 1.3% (34/2624), of HSV in 1.24% (37/2994), of EV in 0.4% (10/2364), of HHV-6 in 0.17% (4/2417), and of CMV in 0.2% (5/2514) of the patients. Newborns and elderly people showed highest infection rates. HSV, VZV, and EV prevailed in typical infectious central nervous system (CNS) diseases; EBV, in further inflammatory neurological diseases; HSV and EBV, in immunocompromised patients; and EBV, HSV, and HHV-6, in further non-inflammatory neurological diseases. Analysis of successive PCR studies revealed delayed viral detection for EBV (6/147) and HSV (1/217), respectively. Rapid viral clearance was typical for HSV, VZV, CMV, and EV infections, although the maximum duration of viral detection was 15days for HSV and 12days for VZV, respectively. This suggests that the detection of HSV, VZV, CMV, and EV strongly indicates symptomatic viral CNS disease. Secondary viral reactivation mostly underlies positive EBV and HHV-6 findings. Their detection does not rule out clinical impact but recommends searching for additional underlying conditions.

Development of the stapedius muscle canal and its possible clinical consequences

OBJECTIVE

To study the development of the stapedius muscle canal in human embryos and foetuses.

MATERIALS AND METHODS

46 temporal bones with ages between 9mm and new-borns were studied. The preparations were dyed using Martins' trichrome technique.

RESULTS

Two areas of different embryological origin form the stapedius muscle canal, which contains this muscle and the facial nerve. On the otic capsule, at 11 weeks an extension starts to grow from its caudal part, which moves outwards and near to Reichert's cartilage, forming the footplate and internal wall. The pyramidal eminence comes from the mesenchyme that surrounds the muscle, forming a partition to separate it from the laterohyale portion of Reichert's cartilage. Extensive connections are observed in its development between bone marrow and mesenchyme. At 35 weeks the muscle and nerve start to separate by means of a bony partition. If this partition does not form, there is going to be a dehiscence that could cause peripheral nerve pathology due to the repeated contraction of the muscle, or the dissemination of infections from middle ear.

CONCLUSION

During the development of the stapedius muscle canal the presence of dehiscences between the facial nerve and the muscle may have clinical repercussions.