novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged from Wuhan, China, in December 2019, resulting in a severe outbreak of pneumonia 1 ; SARS-CoV-2 causes a clinical syndrome, coronavirus disease 2019 (COVID-19), and its pulmonary manifestations have been well described. There is growing evidence of neurological complications and disease in patients with COVID-19. Two similar human coronaviruses (CoV), Middle East respiratory syndrome (MERS-CoV) and severe acute respiratory syndrome (SARS-CoV-1), have also been associated with neurological disease in rare cases. This raises the questions of whether SARS-CoV-2 is neurotropic and whether it contributes to postinfectious neurologic complications. A handful of case reports have described neurological complications in patients with COVID-19. 1-4 However, it remains unknown to what extent SARS-CoV-2 damages the central nervous system (CNS) or if neurological symptoms are attributable to secondary mechanisms. Search Strategy and Selection Criteria References for this review were identified by searches of PubMed from April to May 2020 for articles published between 1969 and April 2020, as well as references from relevant articles. The search terms COVID-19, SARS-CoV-2, SARS-CoV, MERS-CoV, HCoV-OC43, neurotropism, neuroinvasion, and coronavirus were used. There were no language restrictions. The final list of included articles was generated on the basis of relevance to the topics covered in this review. Neurotropic Coronaviruses Coronaviruses (CoV) are large, enveloped, positive-sense RNA viruses divided into 3 genera: alphacoronavirus, betacoronavirus, and gammacoronavirus. 5 These viruses infect humans and numerous animal species, generally causing upper or lower respiratory tract, IMPORTANCE Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in December 2019, causing human coronavirus disease 2019 (COVID-19), which has now spread into a worldwide pandemic. The pulmonary manifestations of COVID-19 have been well described in the literature. Two similar human coronaviruses that cause Middle East respiratory syndrome (MERS-CoV) and severe acute respiratory syndrome (SARS-CoV-1) are known to cause disease in the central and peripheral nervous systems. Emerging evidence suggests COVID-19 has neurologic consequences as well. OBSERVATIONS This review serves to summarize available information regarding coronaviruses in the nervous system, identify the potential tissue targets and routes of entry of SARS-CoV-2 into the central nervous system, and describe the range of clinical neurological complications that have been reported thus far in COVID-19 and their potential pathogenesis. Viral neuroinvasion may be achieved by several routes, including transsynaptic transfer across infected neurons, entry via the olfactory nerve, infection of vascular endothelium, or leukocyte migration across the blood-brain barrier. The most common neurologic complaints in COVID-19 are anosmia, ageusia, and headache, but other diseases, such as s...

Genetic defects in distinct domains of the nuclear-envelope proteins lamin A and lamin C selectively cause dilated cardiomyopathy with conduction-system disease or autosomal dominant Emery-Dreifuss muscular dystrophy. Missense mutations in the rod domain of the lamin A/C gene provide a genetic cause for dilated cardiomyopathy and indicate that this intermediate filament protein has an important role in cardiac conduction and contractility.

BackgroundCerebrospinal fluid (CSF) neurofilament light chain protein (NFL) is a sensitive marker of neuronal injury in a variety of neurodegenerative conditions, including the CNS dysfunction injury that is common in untreated HIV infection. However, an important limitation is the requirement for lumbar puncture. For this reason, a sensitive and reliable blood biomarker of CNS injury would represent a welcome advance in both clinical and research settings.MethodsTo explore whether plasma concentrations of NFL might be used to detect CNS injury in HIV infection, an ultrasensitive Single molecule array (Simoa) immunoassay was developed. Using a cross-sectional design, we measured NFL in paired CSF and plasma samples from 121 HIV-infected subjects divided into groups according to stage of their systemic disease, presence of overt HIV-associated dementia (HAD), and after antiretroviral treatment (ART)-induced viral suppression. HIV-negative controls were also examined.FindingsPlasma and CSF NFL concentrations were very highly correlated (r = 0.89, P < 0.0001). While NFL was more than 50-fold lower plasma than CSF it was within the quantifiable range of the new plasma assay in all subjects, including the HIV negatives and the HIV positives with normal CSF NFL concentrations. The pattern of NFL changes were almost identical in plasma and CSF, both exhibiting similar age-related increases in concentrations along with highest values in HAD and substantial elevations in ART-naïve neuroasymptomatic subjects with low blood CD4+ T cells.InterpretationThese results show that plasma NFL may prove a valuable tool to evaluate ongoing CNS injury in HIV infection that may be applied in the clinic and in research settings to assess the presence if active CNS injury. Because CSF NFL is also elevated in a variety of other CNS disorders, sensitive measures of plasma NFL may similarly prove useful in other settings.

CSF HIV RNA was detectable in humans as early as 8 days after exposure. CNS inflammation was apparent by CSF analysis and MRS in some individuals during acute HIV infection.

Human immunodeficiency virus type 1 (HIV-1) infection of the central nervous system (CNS) can lead to the development of HIV-1-associated dementia (HAD). We examined the virological characteristics of HIV-1 in the cerebrospinal fluid (CSF) of HAD subjects to explore the association between independent viral replication in the CNS and the development of overt dementia. We found that genetically compartmentalized CCR5-tropic (R5) T cell-tropic and macrophage-tropic HIV-1 populations were independently detected in the CSF of subjects diagnosed with HIV-1-associated dementia. Macrophage-tropic HIV-1 populations were genetically diverse, representing established CNS infections, while R5 T cell-tropic HIV-1 populations were clonally amplified and associated with pleocytosis. R5 T cell-tropic viruses required high levels of surface CD4 to enter cells, and their presence was correlated with rapid decay of virus in the CSF with therapy initiation (similar to virus in the blood that is replicating in activated T cells). Macrophage-tropic viruses could enter cells with low levels of CD4, and their presence was correlated with slow decay of virus in the CSF, demonstrating a separate long-lived cell as the source of the virus. These studies demonstrate two distinct virological states inferred from the CSF virus in subjects diagnosed with HAD. Finally, macrophage-tropic viruses were largely restricted to the CNS/CSF compartment and not the blood, and in one case we were able to identify the macrophage-tropic lineage as a minor variant nearly two years before its expansion in the CNS. These results suggest that HIV-1 variants in CSF can provide information about viral replication and evolution in the CNS, events that are likely to play an important role in HIV-associated neurocognitive disorders.

Neurological symptoms highlight the need to understand pathophysiologic mechanisms

Background Occasional cases of viral escape in cerebrospinal fluid (CSF) despite suppression of plasma HIV-1 RNA have been reported. We investigated CSF viral escape in subjects treated with commonly used ART regimens in relation to intrathecal immune activation and CNS penetration effectiveness (CPE) rank. Methods Sixty-nine neurologically asymptomatic subjects treated with ART >6 months and plasma HIV-1 RNA <50 copies/ml were cross-sectionally included in the analysis. ART regimens included efavirenz, lopinavir/ritonavir or atazanavir/ritonavir combined with tenofovir, abacavir or zidovudine and emtricitabine or lamivudine. HIV-1 RNA was analysed with real-time PCR assays. Neopterin was analysed by ELISA. Results Seven (10%) of the 69 subjects had detectable CSF HIV-1 RNA, in median (IQR) 121 (54–213) copies/ml. Subjects with detectable CSF virus had significantly higher CSF neopterin and longer duration of treatment. Previous treatment interruptions were more common in subjects with CSF escape. CPE-rank was not a significant predictor of detectable CSF virus or CSF neopterin levels. Conclusions Viral escape in CSF is more common than previously reported, suggesting that low-grade CNS infection may continue in treated patients. Although these findings need extension in longitudinal studies, they suggest the utility of monitoring CSF responses, as new treatment combinations and strategies modify clinical practice.

Objective To characterize HIV-infected patients with neuro-symptomatic CSF ‘escape,’ defined as detectable CSF HIV RNA in the setting of treatment-suppressed plasma levels or CSF RNA >1 log higher than plasma RNA. Design Retrospective case series. Setting 4 urban medical centers in the United States and Europe. Subjects Virologically controlled HIV-infected patients on antiretroviral therapy (ART) with progressive neurologic abnormalities who were determined to have CSF ‘escape.’ Intervention Optimization of ART based upon drug susceptibility and presumed CNS exposure. Main outcome measures Levels of CSF HIV RNA and inflammatory markers, clinical signs and symptoms, magnetic resonance imaging findings. Results 10 patients presented with new neurological abnormalities, which included sensory, motor, and cognitive manifestations. Median CSF HIV RNA was 3900 copies/mL (range 134-9056), while median plasma HIV RNA was 62 copies/mL (range <50-380). Median CD4+ T cell count was 482 cells/mm3 (range, 290-660). All patients had been controlled <500 copies/mL for median 27.5 months (range, 2-96) and 5/10 had been suppressed <50 copies/mL for median 19.5 months (range, 2-96). Patients had documentation of a stable ART regimen for median 21 months (range 9-60). All had CSF pleocytosis or elevated CSF protein; 7/8 had abnormalities on MRI; and 6/7 harbored CSF resistance mutations. Following optimization of ART, 8/9 patients improved clinically. Conclusions The development of neurologic symptoms in patients on ART with low or undetectable plasma HIV levels may be an indication of CSF ‘escape.’ This study adds to a growing body of literature regarding this rare condition in well-controlled HIV infection.