Human Immunodeficiency Virus Type 1 and Tuberculosis Coinfection in Multinational, Resource-limited Settings: Increased Neurological Dysfunction

Gliosis, misfolded protein aggregation, and neuronal loss in a guinea pig model of pulmonary tuberculosis

Tuberculosis, caused by Mycobacterium tuberculosis infection, is an ongoing epidemic with an estimated ten million active cases of the disease worldwide. Pulmonary tuberculosis is associated with cognitive and memory deficits, and patients with this disease are at an increased risk for Parkinson's disease and dementia. Although epidemiological data correlates neurological effects with peripheral disease, the pathology in the central nervous system is unknown. In an established guinea pig model of low-dose, aerosolized Mycobacterium tuberculosis infection, we see behavior changes and memory loss in infected animals. We correlate these findings with pathological changes within brain regions related to motor, cognition, and sensation across disease progression. This includes microglial and astrocytic proliferation and reactivity. These cellular changes are followed by the aggregation of neurotoxic amyloid β and phosphorylated tau and, ultimately, neuronal degeneration in the hippocampus. Through these data, we have obtained a greater understanding of the neuropathological effects of a peripheral disease that affects millions of persons worldwide.

Bioinformation Analysis Reveals IFIT1 as Potential Biomarkers in Central Nervous System Tuberculosis

Objective

Central nervous system tuberculosis is the most serious form of extrapulmonary tuberculosis. We aim to discover potential biomarkers involved in the development of the disease.

Methods

Through gene difference analysis, construction of a protein interaction network and tissue specific analysis and other bioinformatics analysis methods, we found out the relatively high expression of important substances in the central nervous system, interferon induced protein with tetratricopeptide repeats 1. Subsequently, the lesion tissue and the resection margin tissue away from the lesion were collected from the 6 cases of central nervous system tuberculosis patients diagnosed from 2019 to 2020, and the pathological manifestations were observed by Hematoxylin and Eosin (H&E) staining, and the expression of IFIT1 was verified by immunohistochemistry.

Results

A total of 101 differential genes were analyzed between extrapulmonary tuberculosis patients and normal people, and they were mainly enriched in the interferon pathway. The protein interaction network unearthed 34 key genes. Through tissue specific analysis, it was found that IFIT1 is relatively high in the central nervous system. H&E staining showed the expression of multinucleated macrophages, and immunohistochemistry showed that IFIT1 was significantly positively expressed in the lesion tissue.

Conclusion

IFIT1 is an important substance involved in central nervous system tuberculosis.

Central Nervous System Effects of COVID-19 in People with HIV Infection

The convergence of the HIV and SARS-CoV-2 pandemics is an emerging field of interest. In this review, we outline the central nervous system (CNS) effects of COVID-19 in the general population and how these effects may manifest in people with HIV (PWH). We discuss the hypothetical mechanisms through which SARS-CoV-2 could impact the CNS during both the acute and recovery phases of infection and the potential selective vulnerability of PWH to these effects as a result of epidemiologic, clinical, and biologic factors. Finally, we define key research questions and considerations for the investigation of CNS sequelae of COVID-19 in PWH.

Central Nervous System Tuberculosis (CNS-TB) in treated HIV-infected adults in Tikur Anbessa Specialized Hospital, Ethiopia: A cross sectional study

BACKGROUND

Central nervous system (CNS) tuberculosis (TB) is a calamitous infection with high rates of morbidity and mortality. Underlying HIV infection often increases susceptibility for acquiring TB and also complicates TB treatment. The study objectives were to assess the burden of CNS TB and associated factors in treatment experienced HIV infected adults.

METHODS

A single-center observational cross-sectional study was conducted between December 2019 and June 2020. Both descriptive and analytical statistics were used to analyze the data.

RESULTS

Ninety-five HIV infected adults with presumptive TB-HIV co-infection on combination antiretroviral therapy for median of 144 months were assessed. The mean age was 40.8 years (1SD = 12.4). Male to female ratio was 1:2. The prevalence of CNS tuberculosis was 56.8% (TB menigitis 53.7%, tuberculoma 2.1%, and spinal TB 1.1%). Patients with CNS TB were younger compared to those with extra CNS TB (38.6 vs. 43.6 years, p = 0.04). A higher proportion of patients with CNS TB had undetectable HIV RNA compared to those with extra CNS TB (55.8% vs. 36.8% p = 0.04). In multivariate regression analysis, advanced disease stages, deferred cotrimoxazole preventive therapy (CPT), and deferred INH preventive therapy (IPT) were found to be independent predictors of CNS TB. Although not statistically significant, the trend for HIV-associated cognitive decline was higher in the group with CNS TB.

CONCLUSION

The prevalence of CNS TB was higher among HIV-infected adults with TB-HIV co-infection. TB meningitis was the most common type of CNS TB. Advanced disease stages, deferred CPT, and deferred IPT were predictors of CNS tuberculosis. Although statistically not-significant, the trend for HAND was higher in the group diagnosed with CNS tuberculosis.

Characterization of HIV-Associated Neurocognitive Impairment in Middle-Aged and Older Persons With HIV in Lima, Peru

Background: With widespread use of antiretroviral medications, people living with HIV (PWH) are living longer worldwide, increasing their risk of developing neurocognitive impairment (NCI). The proportion of Peruvians over age 60 is expected to increase to 25% of the population by 2050, including PWH. Therefore, the problem of aging and NCI, especially in the setting of HIV infection, is uniquely pressing. We sought to study the rates of and risk factors associated with NCI among middle-aged and older PWH in Lima, Peru. Materials and Methods: Sociodemographic, medical (infectious and non-infectious), and psychiatric comorbidity and laboratory data were collected. We administered a brief neuropsychological battery evaluating seven cognitive domains affected in HIV-associated NCI and a depression screening. Cognitive test raw scores were converted to T-scores that were demographically adjusted. Descriptive statistics were performed together with regression (unadjusted and adjusted) analyses to determine potential risk factors for NCI among PWH. Results: This was a cross-sectional study in which 144 PWH aged ≥40 years attending a large HIV clinic in Lima, Peru, were recruited from September 2019 to March 2020. Mean age was 51.6 ± 7.7 years, and mean years of education were 14.0 ± 3.1 with 15% females. Median [interquartile range (IQR)] current CD4 and nadir CD4 were 554 (371, 723) and 179 (83, 291), respectively, and 10% currently had AIDS. The prevalence of NCI was 28.5%, and many demonstrated difficulty with attention and working memory (70%). One-quarter of PWH had mild depression or worse on Patient Health Questionnaire 9 (PHQ-9 ≥ 5). In bivariate analyses, neither a depression history nor a higher PHQ-9 score correlated with NCI. No other non-communicable medical or psychiatric comorbidity nor HIV characteristic was predictive of NCI. Having a positive lifetime history of hepatitis B infection, pulmonary tuberculosis, or syphilis increased risk of NCI (PR 1.72; 95% CI 1.04-2.86) in unadjusted analyses, but not in adjusted analyses. Conclusions: NCI among older Peruvians with HIV was found to be highly prevalent with levels consistent with prior reports of HIV-associated NCI worldwide. Common latent HIV-associated co-infections, including latent syphilis, hepatitis B infection, or pulmonary tuberculosis, may increase the risk of NCI among middle-aged and older PWH in Peru.

The Impact of Antiretroviral Therapy on Neurocognitive Outcomes Among People Living with HIV in Low- and Middle-Income Countries (LMICs): A Systematic Review

Low and middle-income countries (LMICs) are the epicenter of the HIV epidemic. The scale-up of antiretroviral therapy (ART) has reduced mortality, but HIV-associated neurocognitive impairment (HANI) remains prevalent, which impacts functional performance, medication adherence, and quality of life. We aimed to evaluate the effect of ART on neurocognitive outcomes among people living with HIV/AIDS in LMICs and to identify determinants of these outcomes. We searched electronic databases and reference lists for studies published between 1996 and 2019. Two reviewers screened the primary studies for inclusion and performed the critical appraisal. Results were synthesized using the 'Synthesis without meta-analysis' approach through simple vote counting. We identified 31 studies conducted across four regions (Africa, Asia, South America, and Eastern Europe). Nine studies were cross-sectional, 15 were prospective, and seven were randomized controlled trials. The majority of the articles showed improved neurocognitive performance with ART use but found no association with treatment duration, regimen, central penetrating effectiveness, and conventional biomarkers. Despite the lack of appropriate norms and not accounting for practice effect in most studies, the evidence suggests ART is useful in the treatment of HIV-associated neurocognitive impairment (HANI) but limited in addressing legacy effects, and peripheral, and central viral reservoirs. Improved early ART treatment programs, viral reservoir eradication strategies, and identification of novel biomarkers will be critical in efforts to minimize HIV-associated neurocognitive impairment. PROSPERO registration: CRD42020152908.

Cognitive disorders in people living with HIV

High rates of cognitive disorders in antiretroviral-treated people living with HIV have been described worldwide. The exact prevalence of such cognitive disorders is determined by the definitions used, and the presence of these cognitive disorders significantly impacts the overall wellbeing of people with HIV. With the cohort of people with HIV becoming increasingly older, and having high rates of comorbidities and concomitant medication use, rates of cognitive disorders are likely to increase. Conversely, interventions are being sought to reduce the size of the latent HIV reservoir. If successful, such interventions are likely to also reduce the HIV reservoir in the brain compartment, which could result in improvements in cognitive function and reduced rates of impairment.

Low-Level Ionizing Radiation Induces Selective Killing of HIV-1-Infected Cells with Reversal of Cytokine Induction Using mTOR Inhibitors

HIV-1 infects 39.5 million people worldwide, and cART is effective in preventing viral spread by reducing HIV-1 plasma viral loads to undetectable levels. However, viral reservoirs persist by mechanisms, including the inhibition of autophagy by HIV-1 proteins (i.e., Nef and Tat). HIV-1 reservoirs can be targeted by the "shock and kill" strategy, which utilizes latency-reversing agents (LRAs) to activate latent proviruses and immunotarget the virus-producing cells. Yet, limitations include reduced LRA permeability across anatomical barriers and immune hyper-activation. Ionizing radiation (IR) induces effective viral activation across anatomical barriers. Like other LRAs, IR may cause inflammation and modulate the secretion of extracellular vesicles (EVs). We and others have shown that cells may secrete cytokines and viral proteins in EVs and, therefore, LRAs may contribute to inflammatory EVs. In the present study, we mitigated the effects of IR-induced inflammatory EVs (i.e., TNF-α), through the use of mTOR inhibitors (mTORi; Rapamycin and INK128). Further, mTORi were found to enhance the selective killing of HIV-1-infected myeloid and T-cell reservoirs at the exclusion of uninfected cells, potentially via inhibition of viral transcription/translation and induction of autophagy. Collectively, the proposed regimen using cART, IR, and mTORi presents a novel approach allowing for the targeting of viral reservoirs, prevention of immune hyper-activation, and selectively killing latently infected HIV-1 cells.

Impact of Latent Tuberculosis Infection on Neurocognitive Functioning and Inflammation in HIV-Infected and Uninfected South Indians

BACKGROUND

HIV-associated neurocognitive disorder persists in some people living with HIV despite optimal antiretroviral therapy. Latent tuberculosis infection (LTBI) may cause systemic inflammation and immune activation that may impair brain function. We assessed cognition and biomarkers of inflammation in both HIV+ and HIV- South Indians with and without LTBI.

METHODS

Adults (≥18 years old) with and without HIV infection were screened for LTBI by interferon-gamma release assays, completed comprehensive neurocognitive assessments, and underwent measurement of serum inflammatory biomarker levels.

RESULTS

The participants (n = 119) were HIV+/LTBI+ (n = 15), HIV+/LTBI- (n = 50), HIV-/LTBI+ (n = 26), and HIV-/LTBI- (n = 28). HIV+ participants, regardless of LTBI status, had more impaired global deficit scores than HIV- participants (odds ratio = 3.42, P = 0.028, adjusted for sex and education differences). Neither global deficit scores nor impairment rates differed in the LTBI+ group compared with the LTBI- group (P = 0.79 and P = 0.41, respectively). The mean log10 interleukin (IL)-6 and monocyte chemoattractant protein-1 values were significantly higher and high sensitivity C-reactive protein lower in the LTBI+ group than the LTBI- group (P = 0.044, 0.023, and 0.03, respectively, adjusting for HIV status and sex).

CONCLUSIONS

In this cross-sectional study of South Indians, HIV infection, but not LTBI, was associated with increased neurocognitive impairment. Proinflammatory biomarkers (IL-6 and monocyte chemoattractant protein-1, but not tumor necrosis factor-α) were elevated in the LTBI+ groups compared with the LTBI- groups. Biomarkers of immune activation (interferon-γ, macrophage inflammatory protein-1β, IL-2, interferon gamma inducible protein-10, RANTES, and IL-22) did not differ between these groups. Larger longitudinal studies should be conducted to confirm our findings that the effect of LTBI on systemic inflammation or neurocognitive impairment is likely small.

Distal Sensory Peripheral Neuropathy in Human Immunodeficiency Virus Type 1-Positive Individuals Before and After Antiretroviral Therapy Initiation in Diverse Resource-Limited Settings

BACKGROUND

Distal sensory peripheral neuropathy (DSPN) is a complication of human immunodeficiency virus (HIV). We estimate DSPN prevalence in 7 resource-limited settings (RLSs) for combination antiretroviral therapy (cART)-naive people living with HIV (PLWH) compared with matched participants not living with HIV and in PLWH virally suppressed on 1 of 3 cART regimens.

METHODS

PLWH with a CD4+ count <300 cells/mm3 underwent standardized neurological examination and functional status assessments before and every 24 weeks after starting cART. Matched individuals not living with HIV underwent the same examinations once.Associations between covariates with DSPN at entry were assessed using the χ2 test, and virally suppressed PLWH were assessed using generalized estimating equations.

RESULTS

Before initiating cART, 21.3% of PLWH had DSPN compared with 8.5% of people not living with HIV (n = 2400; χ2(df = 1) = 96.5; P < .00001). PLWH with DSPN were more likely to report inability to work [χ2(df = 1) = 10.6; P = .001] and depression [χ2(df = 1) = 8.9; P = .003] than PLWH without DSPN. Overall prevalence of DSPN among those virally suppressed on cART decreased: 20.3%, week 48; 15.3%, week 144; and 10.3%, week 192. Incident DSPN was seen in 127 PLWH. Longitudinally, DSPN was more likely in older individuals (P < .001) and PLWH with less education (P = .03). There was no significant association between cART regimen and DSPN.

CONCLUSIONS

Although the prevalence of DSPN decreased following cART initiation in PLWH, further research could identify strategies to prevent or ameliorate residual DSPN after initiating cART in RLSs.