Effect of resveratrol on herpesvirus encephalitis: Evidences for its mechanisms of action.

BACKGROUND: Herpes simplex virus type 1 (HSV-1)-induced herpes simplex encephalitis (HSE) has a high mortality rate in clinically immunocompromised patients, while recovered patients often experience neurological sequelae due to neuroinflammation. Nucleoside drugs and nucleoside analogues such as acyclovir and ganciclovir are mainly used in clinical treatment, and the emergence of resistant viral strains makes the development of new anti-herpesvirus encephalitis drugs urgent. Resveratrol is a multifunctional, plant-derived bioactive compound and its antiviral potential is attracting much attention. PURPOSE: This study aimed to investigate the anti-HSV-1 mechanism of resveratrol in microglial cells and in the HSE mouse model. METHODS: The antiviral effect of resveratrol on HSV-1 infection was investigated by plaque assay, virus titer, immunofluorescence, Western blot and time-of-addition assay. The influence of resveratrol on stimulator of interferon gene (STING)/Nuclear Factor kappa B (NF-κB) signaling pathway-mediated neuroinflammation was examined by Western blot, RT-qPCR and ELISA. The interaction between resveratrol and STING/heat shock protein 90 beta (HSP90ß) was evaluated by molecular modeling, co-immunoprecipitation, and drug affinity responsive target stability assay. The therapeutic effect of resveratrol on HSE was evaluated in the HSE mouse model by analyzing weight loss, neurodegenerative symptoms and histopathological scores. RESULTS: Resveratrol inhibited the early process of HSV-1 infection, and interfered with the STING/NF-κB signaling pathway to attenuate HSV-1-induced neuroinflammation and microglial M1 polarization, independent of its classical target Sirtuin1. Mechanistically, resveratrol completely bound to Glu515 and Lys491 of HSP90ß, thus disrupting the HSP90ß-STING interaction and promoting STING degradation. Resveratrol also significantly alleviated viral encephalitis and neuroinflammation caused by HSV-1 in the HSE mouse model. CONCLUSION: Resveratrol acted as a non-classical HSP90ß inhibitor, binding to the STING-HSP90ß interaction site to promote STING degradation and attenuate HSV-1-induced encephalitis and neuroinflammation. These findings suggest the alternative strategy of targeting HSP90ß and resveratrol-mediated inhibition of HSP90ß as a potential antiviral approach.

Neonatal herpes simplex virus encephalitis with intracranial bleeding in a newborn baby with concurrent rhesus incompatibility.

We report a baby with neonatal herpes simplex virus (HSV) encephalitis concurrent with Rrhesus (Rh) incompatibility. He was delivered by a Ggravida 2 mother with a history of miscarriage in her previous pregnancy at a gestation age of 4 months. She had Bblood group 0 and Rrhesus negative. The baby was noticed to have jaundice on day one1 of life accompanied by generalised petechiae on the face and upper chest. A full blood picture revealed severe anaemia and severe thrombocytopaenia and HSV 1/2 IgM was positive. MRI of the brain showed multiple extensive haemorrhagic lesions on the frontal-temporal regions.

Herpes simplex virus infection induces necroptosis of neurons and astrocytes in human fetal organotypic brain slice cultures.

BACKGROUND: Herpes simplex virus (HSV) encephalitis (HSE) is a serious and potentially life-threatening disease, affecting both adults and newborns. Progress in understanding the virus and host factors involved in neonatal HSE has been hampered by the limitations of current brain models that do not fully recapitulate the tissue structure and cell composition of the developing human brain in health and disease. Here, we developed a human fetal organotypic brain slice culture (hfOBSC) model and determined its value in mimicking the HSE neuropathology in vitro. METHODS: Cell viability and tissues integrity were determined by lactate dehydrogenase release in supernatant and immunohistological (IHC) analyses. Brain slices were infected with green fluorescent protein (GFP-) expressing HSV-1 and HSV-2. Virus replication and spread were determined by confocal microscopy, PCR and virus culture. Expression of pro-inflammatory cytokines and chemokines were detected by PCR. Cell tropism and HSV-induced neuropathology were determined by IHC analysis. Finally, the in situ data of HSV-infected hfOBSC were compared to the neuropathology detected in human HSE brain sections. RESULTS: Slicing and serum-free culture conditions were optimized to maintain the viability and tissue architecture of ex vivo human fetal brain slices for at least 14 days at 37 °C in a CO2 incubator. The hfOBSC supported productive HSV-1 and HSV-2 infection, involving predominantly infection of neurons and astrocytes, leading to expression of pro-inflammatory cytokines and chemokines. Both viruses induced programmed cell death-especially necroptosis-in infected brain slices at later time points after infection. The virus spread, cell tropism and role of programmed cell death in HSV-induced cell death resembled the neuropathology of HSE. CONCLUSIONS: We developed a novel human brain culture model in which the viability of the major brain-resident cells-including neurons, microglia, astrocytes and oligodendrocytes-and the tissue architecture is maintained for at least 2 weeks in vitro under serum-free culture conditions. The close resemblance of cell tropism, spread and neurovirulence of HSV-1 and HSV-2 in the hfOBSC model with the neuropathological features of human HSE cases underscores its potential to detail the pathophysiology of other neurotropic viruses and as preclinical model to test novel therapeutic interventions.

Adjunctive Intravenous Immunoglobulin and Glucocorticoid Therapy in Severe Herpes Simplex Encephalitis with Excellent Outcome Begs for Larger Trials Evaluating Immunomodulatory Therapy.

BACKGROUND Despite the preponderance of evidence of immune-driven pathophysiology of disease in herpes simplex virus-1 (HSV-1) encephalitis, current treatment paradigms do not officially recommend adjunctive immunomodulatory therapy in addition to acyclovir. This may in part explain the poor long-term outcomes in patients with severe HSV encephalitis. This report is of a 21-year-old man presenting with a 4-day history of nausea, headache, and fever and a diagnosis of HSV-1 encephalitis. CASE REPORT We describe the case of a young male with clinically and radiographically severe HSV-1 encephalitis diagnosed by PCR of cerebrospinal fluid (CSF), who demonstrated immediate improvement upon treatment with intravenous immunoglobulin (IVIG, 0.5 g/kg daily ×3 days) in addition to acyclovir and dexamethasone therapy. Acyclovir therapy was extended beyond 21 days due to persistently positive HSV-1 CSF PCR. He developed N-methyl-D-aspartate (NMDA) receptor antibodies at 6 weeks, but his long-term outcome far exceeded expectations. While some of his neurological deficits appear to be permanent, he is living a normal life. CONCLUSIONS Overwhelming evidence demonstrates that brain injury due to HSV encephalitis is driven by immune reactions stimulated by HSV rather than HSV itself. Nevertheless, use of immunomodulatory therapy such as glucocorticoids and IVIG are left to the discretion of individual clinicians rather than being recommended in treatment guidelines, which instead recommend acyclovir therapy. The present case highlights the potential role of immunomodulatory therapy with IVIG in HSV encephalitis and the importance of early diagnosis and treatment.

The split apparent diffusion coefficient sign: A novel magnetic resonance imaging biomarker for cortical pathology with possible implications in autoimmune encephalitis.

INTRODUCTION: MRI is the imaging modality of choice for assessing patients with encephalopathy. In this context, we discuss a novel biomarker, the "split ADC sign," where the cerebral cortex demonstrates restricted diffusion (high DWI signal and low ADC) and the underlying white matter demonstrates facilitated diffusion (high or low DWI signal and high ADC). We hypothesize that this sign can be used as a biomarker to suggest either acute encephalitis onset or to raise the possibility of an autoimmune etiology. MATERIALS AND METHODS: A full-text radiological information system search of radiological reports was performed for all entities known to produce restricted diffusion in the cortex excluding stroke between January 2012 and June 2022. Initial MRI studies performed upon onset of clinical symptoms were screened for the split ADC sign. RESULTS: 25 subjects were encountered with a positive split ADC sign (15 female; median age = 57 years, range 18-82). Diagnosis included six herpes simplex encephalitis, three peri-ictal MRI changes, eight PRES, two MELAS, and six autoimmune (3 anti-GABAAR, two seronegative, and one anti-Ma2/Ta). Subjects were imaged at a mean 1.8 days after the onset of symptoms (range 0-8). DISCUSSION: We present a novel visual MRI biomarker, the split ADC sign, and highlight its potential usefulness in subjects with encephalopathy to suggest acute disease onset or to raise the possibility of an autoimmune etiology when location-based criteria are applied. When positive, the sign was present on the initial MRI and can therefore be used to help focus further clinical and laboratory workup.

Encefalitis autoinmune posherpética. Caso clínico pediátrico / Autoimmune post-herpes simplex encephalitis. A pediatric clinical case report

La encefalitis por virus herpes simple (VHS) es una causa frecuente de encefalitis grave y potencialmente fatal. La encefalitis autoinmune posherpética (EAPH) afecta a un porcentaje de los pacientes que han presentado encefalitis herpética (EH) y se caracteriza por la aparición de nuevos síntomas neurológico/psiquiátricos, y/o por el empeoramiento de los déficits adquiridos durante la infección viral dentro de un lapso temporal predecible. Se produce por un mecanismo no relacionado con el VHS, sino por fenómenos autoinmunes, y es susceptible de tratamiento con inmunomoduladores. Se presenta el caso de un varón de 5 años de edad con EAPH que requirió tratamiento inmunomodulador, de primera y segunda línea, con buena evolución y remisión de los síntomas.

Herpes simplex virus (HSV) encephalitis is a common cause of severe and potentially fatal encephalitis. Autoimmune post-herpes simplex encephalitis (AIPHSE) affects a percentage of patients who developed herpes simplex encephalitis (HSE) and is characterized by the onset of new neurological/psychiatric symptoms and/or worsening of deficits acquired during the herpes infection within a predictable time frame. It is caused by a mechanism not related to HSV, but by autoimmune conditions, and is susceptible to treatment with immunomodulators. Here we describe the case of a 5-year-old boy with AIPHSE who required first- and second-line immunomodulatory treatment, with an adequate course and remission of symptoms.

A case of successful hormone therapy for refractory hypotension following viral encephalitis: Case report.

RATIONALE: Refractory hypotension is a life-threatening condition that can result from various causes. We report a rare case of refractory hypotension following herpes simplex virus type 1 encephalitis that was successfully treated with hormone therapy. PATIENT CONCERNS: The patient was a 66-year-old male who was admitted to the hospital because of fever, chills, convulsions, and impaired consciousness. He developed respiratory failure and was intubated. Cerebrospinal fluid metagenomic sequencing confirmed herpes simplex virus type 1 infection. He received piperacillin-tazobactam for anti-infection, acyclovir for antiviral therapy, and dexamethasone for anti-inflammatory therapy. He had repeated episodes of hypotension despite fluid resuscitation and vasopressor therapy. DIAGNOSIS: The diagnosis of herpes simplex virus type 1 encephalitis complicated by refractory hypotension was based on the patient's epidemiological history, clinical manifestations, laboratory tests, and imaging studies. Cerebrospinal fluid examination was the most important diagnostic method, which could detect viral nucleic acids. Head magnetic resonance imaging showed a large recent lesion in the right temporal-parietal and insular lobes. INTERVENTIONS: The treatment of refractory hypotension mainly included anti-infection, antiviral, anti-inflammatory, and hormone therapy. Hormone therapy used methylprednisolone shock treatment until tapering withdrawal. Other treatments included fluid resuscitation, vasopressors, anticonvulsants, etc. OUTCOMES: The patient's blood pressure stabilized after receiving methylprednisolone shock treatment, and his mean arterial pressure increased from 73 mm Hg to 92 mm Hg within 24 hours. Three months later, the patient's blood pressure was normal without medication, and he had a good social and physical recovery. LESSONS: This case illustrates the possible role of hormone therapy in restoring blood pressure in patients with refractory hypotension following viral encephalitis. It suggests that adrenal insufficiency or autonomic dysfunction may be involved in the pathophysiology of this condition. Further studies are needed to confirm the efficacy and safety of hormone therapy in this setting.

Neurological syndromes and potential triggers associated with antibodies to neuronal surface antigens.

BACKGROUND: Autoantibodies against surface neuronal antigens have been associated with specific neurological presentations including autoimmune encephalitis (AE), with variable association with neoplasia and infections. METHODS: We described the phenotype and environmental associations of patients with neurological syndromes associated with antibodies against neuronal surface antigens who were referred to a tertiary center in the South of Brazil. All patients were tested for neuronal autoantibodies using cell-based assays. Clinical, radiological, and laboratory findings were retrospectively reviewed. RESULTS: We identified 16 patients, 15 had subacute, and one had a progressive disease course. Among patients with subacute onset, 11 (73 %) were N-Methyl-d-Aspartate receptor (NMDAr-IgG)+, 3 (20 %) were Leucine-rich Glioma-Inactivated-1 (LGI1-IgG)+, and 1 (6 %) was positive for Glycine receptor-IgG. The patient with a progressive disease course had antibodies against IgLON5. Most patients had disease onset in spring and summer suggesting environmental factors for the development of AE. Also, we observed a different pattern of brain lesions when NMDAr-IgG encephalitis followed herpes encephalitis and a previously unreported association with Rosai-Dorfman-Destombe disease. All patients with encephalopathy met criteria for possible AE and all proven NMDAr-IgG+ met criteria for NMDAr-IgG encephalitis. However, only one LGI1-IgG+ patient fulfilled clinical criteria for limbic encephalitis. All but one received high-dose intravenous methylprednisolone, 11 also had intravenous human immunoglobulin, and 4 plasma exchange. Furthermore, all patients received second-line immunotherapy. Importantly, most patients improved with immunotherapy, even when initiated later in the disease course. CONCLUSION: We identified seasonal variability associated with neuronal surface antibodies suggesting environmental triggers. Also, we described the coexistence of NMDAr-IgG encephalitis with histiocytosis. In our series, most patients received second-line immunotherapy. We observed neurologic improvement after treatment even in cases of delayed diagnosis. Increasing the recognition and availability of tests and treatments for these conditions is of paramount importance in low- and middle-income countries.

Herpes Simplex Virus Encephalitis after Recovery from Coronavirus Disease 2019: A Rare Case Report.

An 85-year-old woman was diagnosed with coronavirus disease 2019 (COVID-19). The patient was treated with dexamethasone, and the infection was cured. She later developed a low-grade fever and fell unconscious. Positivity for herpes simplex virus deoxyribonucleic acid polymerase chain reaction (HSV-DNA PCR) was detected in the cerebrospinal fluid, so she was diagnosed with HSV encephalitis. The patient was treated with antiviral drugs and recovered from the HSV encephalitis. This case suggests that, in patients with COVID-19 and disorders of consciousness, the possibility of HSV encephalitis should be considered along with COVID-19 encephalitis.

Case report: severe course of encephalitis of unknown origin.

The exact cause of encephalitis is still unclear in many cases, although the common etiological factors of this process are viruses such as herpes simplex virus and rabies virus, and also bacteria, fungi, parasites, several medicines and autoimmune diseases. Herein, we report a case of a 56-year-old man with a history of amnestic syndrome, impaired consciousness, somnolence throughout the day, headache, dizziness and hypertension, who was admitted to hospital with suspected neurological disease, and imaging features that were consistent with encephalitis of unknown etiology. Methods which were used to examine patient: cerebrospinal fluid testing, PCR examinations for viruses, testing of antibodies against surface antigens, magnetic resonance imaging of the head, psychiatric consultation, oncology consultation. The objective of this study is to demonstrate a case about an uncommon neurologic condition, which every clinician might meet in clinical practice. In this type of cases, the use of steroids such as dexamethasone and methylprednisolone might lead to a full recovery.

Anti-NMDAR encephalitis secondary to acute necrotizing encephalopathy caused by herpes simplex virus infection in infants: Case series.

BACKGROUND: To describe the clinical characteristics of anti-NMDAR encephalitis secondary to acute necrotizing encephalopathy caused by herpes simplex virus encephalitis in infants, and aid in its early recognition, diagnosis and treatment. CASE PRESENTATION: A total of 4 infants were included; all presented with fever, seizures, and progressive disturbances of consciousness and were diagnosed with herpes simplex virus (HSV-1) encephalitis. Cerebrospinal fluid (CSF) protein levels progressively increased, and the head MRI showed necrotizing encephalopathy. There was no significant improvement or recurrence after treatment with acyclovir, dexamethasone, or immunoglobulins. CSF reexamination at 3 weeks to 3 months showed positive anti-NMDAR IgG antibodies and gradual improvement after high-dose methylprednisolone therapy. CONCLUSION: Infants with ANE associated with HSV can develop secondary anti-NMDAR encephalitis, recognition of which is critical to ensure the appropriate institution of immunotherapy after active CNS infection has been ruled out.

Temporal pathway analysis of cerebrospinal fluid proteome in herpes simplex encephalitis.

OBJECTIVES: We examined the temporal changes of the CSF proteome in patients with herpes simplex encephalitis (HSE) during the course of the disease, in relation to anti-N-methyl-D-aspartate receptor (NMDAR) serostatus, corticosteroid treatment, brain MRI and neurocognitive performance. METHODS: Patients were retrospectively included from a previous prospective trial with a pre-specified CSF sampling protocol. Mass spectrometry data of the CSF proteome were processed using pathway analysis. RESULTS: We included 48 patients (110 CSF samples). Samples were grouped based on time of collection relative to hospital admission - T1: ≤ 9 d, T2: 13-28 d, T3: ≥ 68 d. At T1, a strong multi-pathway response was seen including acute phase response, antimicrobial pattern recognition, glycolysis and gluconeogenesis. At T2, most pathways activated at T1 were no longer significantly different from T3. After correction for multiplicity and considering the effect size threshold, 6 proteins were significantly less abundant in anti-NMDAR seropositive patients compared to seronegative: procathepsin H, heparin cofactor 2, complement factor I, protein AMBP, apolipoprotein A1 and polymeric immunoglobulin receptor. No significant differences in individual protein levels were found in relation to corticosteroid treatment, size of brain MRI lesion or neurocognitive performance. CONCLUSIONS: We show a temporal change in the CSF proteome in HSE patients during the course of the disease. This study provides insight into quantitative and qualitative aspects of the dynamic pathophysiology and pathway activation patterns in HSE and prompts for future studies on the role of apolipoprotein A1 in HSE, which has previously been associated with NMDAR encephalitis.

State of the Art: Acute Encephalitis.

Encephalitis is a devastating neurologic disease often complicated by prolonged neurologic deficits. Best practices for the management of adult patients include universal testing for a core group of etiologies, including herpes simplex virus (HSV)-1, varicella zoster virus (VZV), enteroviruses, West Nile virus, and anti-N-methyl-D-aspartate receptor (anti-NMDAR) antibody encephalitis. Empiric acyclovir therapy should be started at presentation and in selected cases continued until a second HSV-1 polymerase chain reaction test is negative. Acyclovir dose can be increased for VZV encephalitis. Supportive care is necessary for other viral etiologies. Patients in whom no cause for encephalitis is identified represent a particular challenge. Management includes repeat brain magnetic resonance imaging, imaging for occult malignancy, and empiric immunomodulatory treatment for autoimmune conditions. Next-generation sequencing (NGS) or brain biopsy should be considered. The rapid pace of discovery regarding autoimmune encephalitis and the development of advanced molecular tests such as NGS have improved diagnosis and outcomes. Research priorities include development of novel therapeutics.

The importance of MRI in the acute phase of herpes encephalitis mimicking an acute ischemic stroke.

The diagnosis of herpes simplex encephalitis (HSE) can present challenges for neurologists and neuroradiologists due to its variable clinical presentation and atypical radiological features. Brain magnetic resonance imaging (MRI) plays a crucial role by identifying some mimicking conditions, including ischemic strokes, through the accurate interpretation of specific sequences. This report highlights a case of misdiagnosed HSE, aiming to discuss the management of similar cases and underscore the relevance of MRI in the emergency setting.

Metagenomic search of viral coinfections in herpes simplex encephalitis patients.

Little is known about concomitant central nervous system (CNS) infections by more than one virus. Current diagnostics are based on molecular tests for particular pathogens making it difficult to identify multi-viral infections. In the present study, we applied DNA- and RNA-based next-generation sequencing metagenomics (mNGS) to detect viruses in cerebrospinal fluids from 20 patients with herpes simplex encephalitis. Coinfection was detected in one patient: sequences in cerebrospinal fluids matched enterovirus A (2.660 reads; 4% of recovered genome) and enterovirus B (1.571 reads; 13% of recovered genome). Subsequent PCR combined with serotyping allowed to identify human echovirus 6, a representative of enterovirus B. Several other mNGS hits (human pegivirus, Merkel cell polyomavirus, human papillomavirus type 5) were not considered to represent a genuine signal as they could not be confirmed by specific RT-PCR/PCR. HSV DNA, while being detectable by PCR in every patient, was detected by mNGS in only one. In conclusion, contaminations and false signals may complicate mNGS interpretation; however, the method can be useful in diagnostics of viral coinfections in CNS, particularly in the case of rare pathogens.