Demyelination associated with HSV-1-induced facial paralysis

The Alterations and Significance of Intercellular Adhesion Molecule-1 in Mouse Brainstem During Herpes Simplex Virus Type 1-Induced Facial Palsy

Herpes simplex virus type 1 (HSV-1) results in the development of Bell's pals but still, the pathophysiology of the facial nerve paralysis is still not fully studied. The main objective is to establish an animal model of type 1 herpes simplex virus (HSV-1)-induced face paralysis in the mouse and to investigate the pattern of changes in intercellular adhesion molecule -1(ICAM-1) expression in the facial nucleus of the brain stem in mice with facial paralysis as well as the effects of glucocorticoids on intercellular adhesion molecule -1(ICAM-1) expression. A total of 170 4-week-old Balb/c male mice were randomly divided into the virus inoculation group (n = 135), saline control group (n = 26), and blank control group (n = 9). Mice in the virus inoculation group that showed facial paralysis were divided into A, B, and C subgroups. The A group did not receive any treatments, the B group received methylprednisolone sodium succinate (MPSS) intervention, and the C group received MPSS + RU486 treatment. The mouse model of facial paralysis was established by inoculating HSV-1 to the skin at the back of the ears. The facial nerve function of mice was assessed, and real-time PCR and western blot were used to assess ICAM-1 expression in the facial nucleus of the brain stem in mice with facial paralysis after drug intervention. In the virus inoculation group, 95 mice (55.88%) showed varying degrees of facial paralysis symptoms within 2-5 days after inoculation. The ICAM-1 gene and protein expression levels remained at low levels in the facial nucleus of the brain stem of mice in the saline group, which showed no significant difference compared to the normal control group (P > 0.05). However, for mice of the virus inoculation group, ICAM-1 expression increased at 6 h after the occurrence of facial paralysis and peaked after 2 days, differing significantly from the blank control group (P < 0.01). ICAM-1 expression subsequently decreased gradually. In the HSV-1 + MPSS group, ICAM-1 protein expression decreased significantly on the 2^nd day after facial paralysis. In the HSV-1 + MPSS + RU486 group, MPSS inhibition of ICAM-1 protein expression was reduced. The results suggested that ICAM-1 is involved in the pathological processes by which HSV-1 induces facial paralysis in mice, and the treatment effects of MPSS for Bell's palsy can be achieved by the inhibition of MCP-1.

Prevesicular herpes zoster lumbar radiculopathy with transient motor paresis: A case report

RATIONALE

Herpes zoster frequently causes dermatomal vesicular rash accompanied by severe neuralgia, and reaching a differential diagnosis may be challenging before the appearance of the vesicular rash.

PATIENT CONCERNS

A 40-year-old male patient visited the emergency department with a complaint of sudden onset motor weakness and ipsilateral radiating neuralgia to the Lt. thigh. He had suffered from chickenpox during childhood.

DIAGNOSES

No skin lesion was present at the initial visit. The reverse Straight Leg Raise test was negative. Magnetic resonance imaging showed asymmetrically swollen dorsal root ganglion with Gadolinium enhancement. The vesicular rash that appeared on the sixth day after the symptom onset led to the diagnosis of herpes zoster.

INTERVENTIONS

Antiviral agent of valacyclovir (1000 mg t.i.d.) was administered for 7 days.

OUTCOMES

The patient recovered from motor weaknesses by 2 weeks from the onset of the symptom. Mild degree post-herpetic neuralgia recovered by 2 months.

LESSONS

A high index of suspicion is necessary to differentiate early herpes zoster radiculitis before the appearance of vesicular rash from compressive radiculopathy. In L2-3 ipsilateral radiating pain along the dermatome or myotome, the absence of reverse Straight Leg Raise sign may be a possible factor in differentiating herpes zoster radiculitis from compressive radiculopathy.

HSV-1 and Endogenous Retroviruses as Risk Factors in Demyelination

Herpes simplex virus type 1 (HSV-1) is a neurotropic alphaherpesvirus that can infect the peripheral and central nervous systems, and it has been implicated in demyelinating and neurodegenerative processes. Transposable elements (TEs) are DNA sequences that can move from one genomic location to another. TEs have been linked to several diseases affecting the central nervous system (CNS), including multiple sclerosis (MS), a demyelinating disease of unknown etiology influenced by genetic and environmental factors. Exogenous viral transactivators may activate certain retrotransposons or class I TEs. In this context, several herpesviruses have been linked to MS, and one of them, HSV-1, might act as a risk factor by mediating processes such as molecular mimicry, remyelination, and activity of endogenous retroviruses (ERVs). Several herpesviruses have been involved in the regulation of human ERVs (HERVs), and HSV-1 in particular can modulate HERVs in cells involved in MS pathogenesis. This review exposes current knowledge about the relationship between HSV-1 and human ERVs, focusing on their contribution as a risk factor for MS.

The Role of Herpes Simplex Virus Type 1 Infection in Demyelination of the Central Nervous System

Herpes simplex type 1 (HSV-1) is a neurotropic virus that infects the peripheral and central nervous systems. After primary infection in epithelial cells, HSV-1 spreads retrogradely to the peripheral nervous system (PNS), where it establishes a latent infection in the trigeminal ganglia (TG). The virus can reactivate from the latent state, traveling anterogradely along the axon and replicating in the local surrounding tissue. Occasionally, HSV-1 may spread trans-synaptically from the TG to the brainstem, from where it may disseminate to higher areas of the central nervous system (CNS). It is not completely understood how HSV-1 reaches the CNS, although the most accepted idea is retrograde transport through the trigeminal or olfactory tracts. Once in the CNS, HSV-1 may induce demyelination, either as a direct trigger or as a risk factor, modulating processes such as remyelination, regulation of endogenous retroviruses, or molecular mimicry. In this review, we describe the current knowledge about the involvement of HSV-1 in demyelination, describing the pathways used by this herpesvirus to spread throughout the CNS and discussing the data that suggest its implication in demyelinating processes.

Axonal variants of Guillain-Barré syndrome: an update

Axonal variants of Guillain-Barré syndrome (GBS) mainly include acute motor axonal neuropathy, acute motor and sensory axonal neuropathy, and pharyngeal-cervical-brachial weakness. Molecular mimicry of human gangliosides by a pathogen's lipooligosaccharides is a well-established mechanism for Campylobacter jejuni-associated GBS. New triggers of the axonal variants of GBS (axonal GBS), such as Zika virus, hepatitis viruses, intravenous administration of ganglioside, vaccination, and surgery, are being identified. However, the pathogenetic mechanisms of axonal GBS related to antecedent bacterial or viral infections other than Campylobacter jejuni remain unknown. Currently, autoantibody classification and serial electrophysiology are cardinal approaches to differentiate axonal GBS from the prototype of GBS, acute inflammatory demyelinating polyneuropathy. Newly developed technologies, including metabolite analysis, peripheral nerve ultrasound, and feature selection via artificial intelligence are facilitating more accurate diagnosis of axonal GBS. Nevertheless, some key issues, such as genetic susceptibilities, remain unanswered and moreover, current therapies bear limitations. Although several therapies have shown considerable benefits to experimental animals, randomized controlled trials are still needed to validate their efficacy.

Immune-related gene expression profiles of hypothermia adipocytes: Implications for Bell's palsy

OBJECTIVE

To identify immune-related gene expression profiles of adipocytes under low temperatures with RNA sequencing as a model for Bell's palsy implications.

METHODS

Adipocytes were harvested from the white adipose tissue of male Sprague-Dawley rats and cultured under different acute-grade cold exposure conditions of 30, 20, and 10°C, and their genomes were sequenced for RNA sequencing analysis. The differentially expressed genes (DEGs) were validated with reverse transcription polymerase chain reaction.

RESULTS

In total, 55 (35 upregulated and 20 downregulated), 121 (76 upregulated and 45 downregulated), and 92 (64 upregulated and 28 downregulated) DEGs were identified under 30, 20, and 10°C compared with the control, respectively. KEGG and GO analysis revealed that the DEGs were considerably enriched in immune-related pathways (leukocyte transendothelial migration and platelet activation) and infection (bacterial invasion of epithelial cells and Salmonella infection). The levels of key inflammatory chemokines (CSF1, CXCL1, CCL2, and CCL7) were enhanced after cold exposure.

CONCLUSION

These findings broaden our understanding of the immune responses to cold exposure in adipocytes. The molecular profiles of adipocyte immune function will help clarify the potential mechanism impacting myelin, which might contribute to the development of strategies to control Bell's palsy.

[Bell's palsy]

Idiopathic peripheral facial palsy, also named Bell's palsy, is the most common cause of peripheral facial palsy in adults. Although it is considered as a benign condition, its social and psychological impact can be dramatic, especially in the case of incomplete recovery. The main pathophysiological hypothesis is the reactivation of HSV 1 virus in the geniculate ganglia, leading to nerve edema and its compression through the petrosal bone. Patients experience an acute (less than 24 hours) motor deficit involving ipsilateral muscles of the upper and lower face and reaching its peak within the first three days. Frequently, symptoms are preceded or accompanied by retro-auricular pain and/or ipsilateral face numbness. Diagnosis is usually clinical but one should look for negative signs to eliminate central facial palsy or peripheral facial palsy secondary to infectious, neoplastic or autoimmune diseases. About 75% of the patients will experience spontaneous full recovery, this rate can be improved with oral corticotherapy when introduced within the first 72 hours. To date, no benefit has been demonstrated by adding an antiviral treatment. Hemifacial spasms (involuntary muscles contractions of the hemiface) or syncinesia (involuntary muscles contractions elicited by voluntary ones, due to aberrant reinnervation) may complicate the disease's course. Electroneuromyography can be useful at different stages: it can first reveal the early conduction bloc, then estimate the axonal loss, then bring evidence of the reinnervation process and, lastly, help for the diagnosis of complications.

Facial paralysis induced by ear inoculation of herpes simplex virus in rat

OBJECTIVE

Bell's palsy is caused by the reactivation of herpes simplex virus type 1 (HSV-1). Using Balb/c mice inoculated with the KOS strain of HSV-1, we previously developed an animal disease model that simulated mild Bell's palsy. The current study developed an animal disease model of more severe facial palsy than that seen in the mouse model.

METHODS

Three-week-old female Wister rats weighing 60-80g were inoculated on the auricle with HSV-1 and acyclovir was administered intraperitoneally to deactivate the infected HSV-1. Instead of HSV-1, phosphate-buffered saline was used for inoculation as a negative control. Quantitative polymerase chain reaction (PCR), behavior testing (blink reflex), electroneuronography, histopathology of the peripheral nerve, and immunohistochemistry of the facial nerve nucleus were evaluated.

RESULTS

Facial palsy occurred 3-5 days after virus inoculation, and the severity of the facial palsy progressed for up to 7 days. Quantitative PCR showed an increase in HSV-1 DNA copies in the facial nerve from 24 to 72h, suggesting that HSV-1 infection occurred in the nerve. Electroneuronography values were 33.0±15.3% and 110.0±18.0% in HSV-1-inoculated and control rats, respectively. The histopathology of the peripheral nerve showed demyelination and loss of the facial nerve, and the facial nerve nucleus showed degeneration.

CONCLUSION

Facial palsy developed in Wister rats following inoculation of the KOS strain of HSV-1 onto the auricles. The behavioral, histopathological, and electroneuronography data suggested that the severity of facial palsy was greater in our rats than in animals in the previous mouse disease model.

The effect of mouse strain on herpes simplex virus type 1 (HSV-1) infection of the central nervous system (CNS)

BACKGROUND

Mice infected with HSV-1 can develop lethal encephalitis or virus induced CNS demyelination. Multiple factors affect outcome including route of infection, virus and mouse strain. When infected with a sub-lethal dose of HSV-1 strain 2 via the oral mucosa, susceptible SJL/J, A/J, and PL/J mice develop demyelinating lesions throughout the brain. In contrast, lesions are restricted to the brainstem (BST) in moderately resistant BALB/c mice and are absent in resistant BL/6 mice. The reasons for the strain differences are unknown.

METHODS

In this study, we combine histology, immunohistochemistry, and in-situ hybridization to investigate the relationship between virus and the development of lesions during the early stage (< 24 days PI) of demyelination in different strains of mice.

RESULTS

Initially, viral DNA and antigen positive cells appear sequentially in non-contiguous areas throughout the brains of BALB/c, SJL/J, A/J, and PL/J mice but are restricted to an area of the BST of BL/6 mice. In SJL/J, A/J, and PL/J mice, this is followed by the development of 'focal' areas of virus infected neuronal and non-neuronal cells throughout the brain. The 'focal' areas follow a hierarchical order and co-localize with developing demyelinating lesions. When antigen is cleared, viral DNA positive cells can remain in areas of demyelination; consistent with a latent infection. In contrast, 'focal' areas are restricted to the BST of BALB/c mice and do not occur in BL/6 mice.

CONCLUSIONS

The results of this study indicate that susceptible mouse strains, infected with HSV-1 via the oral mucosa, develop CNS demyelination during the first 24 days PI in several stages. These include: the initial spread of virus and infection of cells in non-contiguous areas throughout the brain, the development of 'focal' areas of virus infected neuronal and non-neuronal cells, the co-localization of 'focal' areas with developing demyelinating lesions, and latent infection in a number of the lesions. In contrast, the limited demyelination that develops in BALB/c and the lack of demyelination in BL/6 mice correlates with the limited or lack of 'focal' areas of virus infected neuronal and non-neuronal cells in these two strains.

Herpes simplex virus type 1 and Bell's palsy-a current assessment of the controversy

Bell's palsy causes about two thirds of cases of acute peripheral facial weakness. Although the majority of cases completely recover spontaneously, about 30% of cases do not and are at risk from persisting severe facial paralysis and pain. It has been suggested that herpes simplex virus type 1 (HSV-1) may be the etiological agent that causes Bell's palsy. Although corticosteroid therapy is now universally recognized as improving the outcome of Bell's palsy, the question as to whether or not a combination of antiviral agents and corticosteroids result in a better rate of complete facial recovery compared with corticosteroids alone is now a highly contentious issue. The evidence obtained from laboratory studies of animals and humans that HSV-1 may be linked to facial nerve paralysis is first outlined. The discussion then focuses on the results of different clinical trials of the efficacy of antiviral agents combined with corticosteroids in increasing the rate of complete recovery in Bell's palsy. These have often given different results leading to opposite conclusions as to the efficacy of antivirals. Of three recent meta-analyses of previous trials, two concluded that antivirals produce no added benefit to corticosteroids alone in producing complete facial recovery, and one concluded that such combined therapy may be associated with additional benefit. Although it is probably not justified at the present time to treat patients with Bell's palsy with antiviral agents in addition to corticosteroids, it remains to be shown whether antivirals may be beneficial in treating patients who present with severe or complete facial paralysis.

Valacyclovir and prednisolone treatment for Bell's palsy: a multicenter, randomized, placebo-controlled study

OBJECTIVE

To investigate the effects of valacyclovir and prednisolone in comparison with those of placebo and prednisolone for the treatment of Bell's palsy, excluding zoster sine herpete.

STUDY DESIGN

Prospective, multicenter, randomized placebo-controlled study.

SETTING

Six academic tertiary referral centers.

PATIENTS

Ultimately, 221 patients with Bell's palsy who were treated within 7 days of the onset. Serological and polymerase chain reaction examinations were performed to distinguish Bell's palsy from zoster sine herpete.

INTERVENTION

The patients were treated with either valacyclovir (dosage, 1,000 mg/d for 5 days) plus prednisolone (VP [n = 114]) or placebo plus prednisolone (PP [n = 107]) administered orally.

MAIN OUTCOME MEASURE

Recovery from the palsy was defined as a score higher than 36 using Yanagihara 40-point scoring system without facial contracture or synkinesis. The patients were followed up until complete recovery occurred or for more than 6 months in cases with a poor prognosis.

RESULTS

The overall rate of patient recovery among those treated with VP (96.5%) was significantly better (p < 0.05) than the rate among those treated with PP (89.7%). The rate of patient recovery was also analyzed by classifying the initial severity of facial palsy. In cases of complete or severe palsy, the rates of patients treated with VP and PP who recovered were 95.7% (n = 92) and 86.6% (n = 82), respectively; the recovery rate for treatment with VP was significantly better than that with PP (p < 0.05).

CONCLUSION

The valacyclovir and prednisolone therapy was more effective in treating Bell's palsy, excluding zoster sine herpete, than the conventional prednisolone therapy. To our knowledge, this is the first controlled study of an antiviral agent in the treatment of a sufficient number of Bell's palsy cases based on an etiologic background.

Ophthalmic Management of Facial Nerve Palsy: A Review

Facial nerve palsy affects individuals of all ages, races, and sexes. Psychological and functional implications of the paralysis present a devastating management problem to those afflicted, as well as the carriers. Since Sir Charles Bell's original description of facial palsy in 1821, our understanding and treatment options have expanded. It is essential that a multidisciplinary approach, encompassing ophthalmologists; Ear, Nose, and Throat surgeons; plastic surgeons; and psychologists work closely to optimize patient management in a staged approach. Although the etiology remains unknown, strong histological, cerebral spinal fluid, and radiological evidence suggests a possible association with herpes simplex virus in idiopathic facial nerve palsy (Bell's palsy). The use of steroids has been suggested as a means of limiting facial nerve damage in the acute phase. Unfortunately, no single randomized control trial has achieved an unquestionable benefit with the use of oral steroid therapy and thus remains controversial. In the acute phase, ophthalmologists play a pivotal role in preventing irreversible blindness from corneal exposure. This may be successfully achieved by using intensive lubrication, medical therapy (botulinum toxin), or surgery (upper lid weighting or tarsorraphy). Once the cornea is adequately protected and recovery deemed unlikely, longer term planning for eyelid and facial reanimation may take place in an individualized manner. Onset is sudden and management potentially lengthy. Physician empathy, knowledge, and experience are essential in averting long-term lifestyle and psychological discomfort for patients.

The role of viruses in idiopathic peripheral facial palsy and cellular immune response

PURPOSE

The purpose of this study is to investigate the role of viruses on the idiopathic peripheral facial palsy and show the interaction of immune system.

MATERIALS AND METHODS

The levels of immunoglobulin (Ig) G and IgM antibodies against to varicella-zoster virus (VZV), herpes simplex virus (HSV), cytomegalovirus (CMV), Ebstein-Barr virus (EBV), and mumps virus in venous blood taken from patients in the amount of 10 mL have been investigated by enzyme-linked immunosorbent assay method. Tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), and transforming growth factor-beta (TGF-beta) were also examined. Of lymphocyte subpopulation, antibodies of CD3(+), CD4(+), CD8(+), CD19(+), and CD16(+) plus 56(+) were analyzed.

RESULTS

Ten of the patients had HSV-1 IgG; 1 of the patients IgM, 5 of the patients EBV IgG, 6 of the patients VZV IgG, 1 of the patients IgM, 9 of the patients mumps IgG, 1 of the patients IgM, and finally in 7 of the patients CMV IgG antibodies were obtained. It was found that CD4(+) cell and ratio of CD4(+)/CD8(+) lower and the percentage of the CD8(+) and CD16(+) plus 56(+) cells higher compared with the control group (P < .05). The levels of TNF-alpha were lower, whereas IFN-gamma and TGF-beta1 were higher.

CONCLUSION

It may be concluded from these results that VZV, HSV-1, CMV, EBV, and mumps virus play a significant role in the etiology of idiopathic peripheral facial palsy and activate the cellular immunity.