Psychological stress is associated with arterial inflammation in people living with treated HIV infection.

Stress and depression are increasingly recognized as cerebrovascular risk factors, including among high stress populations such as people living with HIV infection (PLWH). Stress may contribute to stroke risk through activation of neural inflammatory pathways. In this cross-sectional study, we examined the relationships between stress, systemic and arterial inflammation, and metabolic activity in stress-related brain regions on 18F-fluorodeoxyglucose (FDG)-PET in PLWH. Participants were recruited from a parent trial evaluating the impact of alirocumab on radiologic markers of cardiovascular risk in people with treated HIV infection. We administered a stress battery to assess different forms of psychological stress, specifying the Perceived Stress Scale as the primary stress measure, and quantified plasma markers of inflammation and immune activation. Participants underwent FDG-PET of the brain, neck, and chest. Age- and sex-matched control participants without HIV infection were selected for brain FDG-PET comparisons. Among PLWH, we used nonparametric pairwise correlations, partial correlations, and linear regression to investigate the association between stress and 1) systemic inflammation; 2) atherosclerotic inflammation on FDG-PET; and metabolic activity in 3) brain regions in which glucose metabolism differed significantly by HIV serostatus; and 4) in a priori defined stress-responsive regions of interest (ROI) and stress-related neural network activity (i.e., ratio of amygdala to ventromedial prefrontal cortex or temporal lobe activity). We studied 37 PLWH (mean age 60 years, 97% men) and 29 control participants without HIV (mean age 62 years, 97% men). Among PLWH, stress was significantly correlated with systemic inflammation (r = 0.33, p = 0.041) and arterial inflammation in the carotid (r = 0.41, p = 0.023) independent of age, race/ethnicity, traditional vascular risk factors and health-related behaviors. In voxel-wise analyses, metabolic activity in a cluster corresponding to the anterior medial temporal lobes, including the bilateral amygdalae, was significantly lower in PLWH compared with controls. However, we did not find a significant positive relationship between stress and this cluster of decreased metabolic activity in PLWH, a priori defined stress-responsive ROI, or stress-related neural network activity. In conclusion, psychological stress was associated with systemic and carotid arterial inflammation in this group of PLWH with treated infection. These data provide preliminary evidence for a link between psychological stress, inflammation, and atherosclerosis as potential drivers of excess cerebrovascular risk among PLWH.

Advancing Diagnosis and Treatment in People Living with HIV and Tuberculosis Meningitis.

PURPOSE OF REVIEW: Tuberculous meningitis (TBM) is the most severe form of tuberculosis. Inadequate diagnostic testing and treatment regimens adapted from pulmonary tuberculosis without consideration of the unique nature of TBM are among the potential drivers. This review focuses on the progress being made in relation to both diagnosis and treatment of TBM, emphasizing promising future directions. RECENT FINDINGS: The molecular assay GeneXpert MTB/Rif Ultra has improved sensitivity but has inadequate negative predictive value to "rule-out" TBM. Evaluations of tests focused on the host response and bacterial components are ongoing. Clinical trials are in progress to explore the roles of rifampin, fluoroquinolones, linezolid, and adjunctive aspirin. Though diagnosis has improved, novel modalities are being explored to improve the rapid diagnosis of TBM. Multiple ongoing clinical trials may change current therapies for TBM in the near future.

Clinical Metagenomic Sequencing for Diagnosis of Meningitis and Encephalitis.

BACKGROUND: Metagenomic next-generation sequencing (NGS) of cerebrospinal fluid (CSF) has the potential to identify a broad range of pathogens in a single test. METHODS: In a 1-year, multicenter, prospective study, we investigated the usefulness of metagenomic NGS of CSF for the diagnosis of infectious meningitis and encephalitis in hospitalized patients. All positive tests for pathogens on metagenomic NGS were confirmed by orthogonal laboratory testing. Physician feedback was elicited by teleconferences with a clinical microbial sequencing board and by surveys. Clinical effect was evaluated by retrospective chart review. RESULTS: We enrolled 204 pediatric and adult patients at eight hospitals. Patients were severely ill: 48.5% had been admitted to the intensive care unit, and the 30-day mortality among all study patients was 11.3%. A total of 58 infections of the nervous system were diagnosed in 57 patients (27.9%). Among these 58 infections, metagenomic NGS identified 13 (22%) that were not identified by clinical testing at the source hospital. Among the remaining 45 infections (78%), metagenomic NGS made concurrent diagnoses in 19. Of the 26 infections not identified by metagenomic NGS, 11 were diagnosed by serologic testing only, 7 were diagnosed from tissue samples other than CSF, and 8 were negative on metagenomic NGS owing to low titers of pathogens in CSF. A total of 8 of 13 diagnoses made solely by metagenomic NGS had a likely clinical effect, with 7 of 13 guiding treatment. CONCLUSIONS: Routine microbiologic testing is often insufficient to detect all neuroinvasive pathogens. In this study, metagenomic NGS of CSF obtained from patients with meningitis or encephalitis improved diagnosis of neurologic infections and provided actionable information in some cases. (Funded by the National Institutes of Health and others; PDAID ClinicalTrials.gov number, NCT02910037.).

Glucocorticoid Receptor Function and Cognitive Performance in Women With HIV.

OBJECTIVE: Alterations in glucocorticoid receptor (GCR) function may be a risk factor for cognitive complications among older people with human immunodeficiency virus (HIV). We evaluated whether HIV serostatus and age modify the GCR function-cognition association among women. METHODS: Eighty women with HIV ( n = 40, <40 years of age [younger]; n = 40, >50 years of age [older]) and 80 HIV-uninfected women ( n = 40 older, n = 40 younger) enrolled in the Women's Interagency HIV Study completed a comprehensive neuropsychological test battery. Peripheral blood mononuclear cells collected concurrent with neuropsychological testing were assessed for GCR function. Multivariable linear regression analyses were conducted to examine whether a) HIV serostatus and age were associated with GCR function, and b) GCR function-cognition associations are moderated by HIV serostatus and age adjusting for relevant covariates. RESULTS: Among older women, higher baseline FKBP5 expression level was associated with lower attention/working memory performance among women with HIV ( B = 6.4, standard error = 1.7, p = .0003) but not in women without HIV infection ( B = -1.7, standard error = 1.9, p = .37). There were no significant HIV serostatus by age interactions on dexamethasone (DEX)-stimulated expression of the genes regulated by the GCR or lipopolysaccharide-stimulated tumor necrosis factor α levels (with or without DEX stimulation; p values > .13). HIV serostatus was associated with GC target genes PER1 ( p = .006) and DUSP1 ( p = .02), but not TSC22D3 ( p = .32), after DEX stimulation. CONCLUSIONS: Collectively, these data suggest that HIV serostatus and age may modify the influence of the GCR, such that the receptor is likely engaged to a similar extent, but the downstream influence of the receptor is altered, potentially through epigenetic modification of target genes.

An Analysis of Stroke Risk Factors by HIV Serostatus in Uganda: Implications for Stroke Prevention in Sub-Saharan Africa.

OBJECTIVE: HIV infection is an important stroke risk factor in sub-Saharan Africa.  However, data on stroke risk factors in the era of antiretroviral therapy (ART) are sparse. We aimed to determine if stroke risk factors differed by HIV serostatus in Uganda. METHODS: We conducted a matched cohort study, enrolling persons living with HIV (PWH) with acute stroke, matched by sex and stroke type to HIV uninfected (HIV-) individuals. We collected data on stroke risk factors and fitted logistic regression models for analysis. RESULTS: We enrolled 262 participants:105 PWH and 157 HIV-. The median ART duration was 5 years, and the median CD4 cell count was 214 cells/uL. PWH with ischemic stroke had higher odds of hypertriglyceridemia (AOR 1.63; 95% CI 1.04, 2.55, p=0.03), alcohol consumption (AOR 2.84; 95% CI 1.32, 6.14, p=0.008), and depression (AOR 5.64; 95%CI 1.32, 24.02, p=0.02) while HIV- persons with ischemic stroke were more likely to be > 55 years of age (AOR 0.43; 95%CI 0.20-0.95, p=0.037), have an irregular heart rhythm (AOR 0.31; 95%CI 0.10-0.98, p=0.047) and report low fruit consumption (AOR 0.39; 95%CI 0.18-0.83, p=0.014).  Among all participants with hemorrhagic stroke (n=78) we found no differences in the prevalence of risk factors between PWH and HIV-. CONCLUSIONS: PWH with ischemic stroke in Uganda present at a younger age, and with a combination of traditional and psychosocial risk factors. By contrast, HIV- persons more commonly present with arrhythmia. A differential approach to stroke prevention might be needed in these populations.

HIV Viremia and Risk of Stroke Among People Living with HIV Who Are Using Antiretroviral Therapy.

BACKGROUND: Rates of stroke are higher in people living with HIV compared with age-matched uninfected individuals. Causes of elevated stroke risk, including the role of viremia, are poorly defined. METHODS: Between 1 January 2006 and 31 December 2014, we identified incident strokes among people living with HIV on antiretroviral therapy at five sites across the United States. We considered three parameterizations of viral load (VL) including (1) baseline (most recent VL before study entry), (2) time-updated, and (3) cumulative VL (copy-days/mL of virus). We used Cox proportional hazards models to estimate hazard ratios (HRs) for stroke risk comparing the 75th percentile ("high VL") to the 25th percentile ("low VL") of baseline and time-updated VL. We used marginal structural Cox models, with most models adjusted for traditional stroke risk factors, to estimate HRs for stroke associated with cumulative VL. RESULTS: Among 15,974 people living with HIV, 139 experienced a stroke (113 ischemic; 18 hemorrhagic; eight were unknown type) over a median follow-up of 4.2 years. Median baseline VL was 38 copies/mL (interquartile interval: 24, 3,420). High baseline VL was associated with increased risk of both ischemic (HR: 1.3; 95% CI = 0.96-1.7) and hemorrhagic stroke (HR: 3.1; 95% CI = 1.6-5.9). In time-updated models, high VL was also associated with an increased risk of any stroke (HR: 1.8; 95% CI = 1.4-2.3). We observed no association between cumulative VL and stroke risk. CONCLUSIONS: Our findings are consistent with the hypothesis that elevated HIV VL may increase stroke risk, regardless of previous VL levels.

Persistent COVID-19-associated neurocognitive symptoms in non-hospitalized patients.

As cases of coronavirus disease 2019 (COVID-19) mount worldwide, attention is needed on potential long-term neurologic impacts for the majority of patients who experience mild to moderate illness managed as outpatients. To date, there has not been discussion of persistent neurocognitive deficits in patients with milder COVID-19. We present two cases of non-hospitalized patients recovering from COVID-19 with persistent neurocognitive symptoms. Commonly used cognitive screens were normal, while more detailed testing revealed working memory and executive functioning deficits. An observational cohort study of individuals recovering from COVID-19 (14 or more days following symptom onset) identified that among the first 100 individuals enrolled, 14 were non-hospitalized patients reporting persistent cognitive issues. These 14 participants had a median age of 39 years (interquartile range: 35-56), and cognitive symptoms were present for at least a median of 98 days (interquartile range: 71-120 following acute COVID-19 symptoms); no participants with follow-up evaluation reported symptom resolution. We discuss potential mechanisms to be explored in future studies, including direct viral effects, indirect consequences of immune activation, and immune dysregulation causing auto-antibody production.

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.

Cocaine Use and White Matter Hyperintensities in Homeless and Unstably Housed Women.

OBJECTIVES: Cocaine use has been linked to stroke in several studies. However, few studies have considered the influence of cocaine use on stroke mechanisms such as small vessel disease (SVD). We conducted a study to assess associations between the toxicology-confirmed use of multiple drugs, including cocaine, and a marker of SVD, white matter hyperintensities (WMH). MATERIALS AND METHODS: We conducted a nested case-control study (n = 30) within a larger cohort study (N = 245) of homeless and unstably housed women recruited from San Francisco community venues. Participants completed six monthly study visits consisting of an interview, blood draw, vital sign assessment and baseline brain MRI. We examined associations between toxicology-confirmed use of multiple substances, including cocaine, methamphetamine, heroin, alcohol and tobacco, and WMH identified on MRI. RESULTS: Mean study participant age was 53 years, 70% of participants were ethnic minority women and 86% had a history of cocaine use. Brain MRIs indicated the presence of WMH (i.e., Fazekas score>0) in 54% (18/30) of imaged participants. The odds of WMH were significantly higher in women who were toxicology-positive for cocaine (Odd Ratio=7.58, p=0.01), but not in women who were toxicology-positive for other drugs or had several other cerebrovascular risk factors. CONCLUSIONS: Over half of homeless and unstably housed women showed evidence of WMH. Cocaine use is highly prevalent and a significant correlate of WMH in this population, while several traditional CVD risk factors are not. Including cocaine use in cerebrovascular risk calculators may improve stroke risk prediction in high-risk populations and warrants further investigation.

Baseline 10-Year Cardiovascular Risk Scores Predict Cognitive Function in Older Persons, and Particularly Women, Living With Human Immunodeficiency Virus Infection.

BACKGROUND: Cardiovascular disease (CVD) and associated comorbidities increase the risk of cognitive impairment in persons living with human immunodeficiency virus (PLWH). Given the potential composite effect of multiple cardiovascular risk factors on cognition, we examined the ability of the Atherosclerotic Cardiovascular Disease (ASCVD) risk score and the Framingham Heart Study Global CVD risk score (FRS) to predict future cognitive function in older PLWH. METHODS: We constructed linear regression models evaluating the association between baseline 10-year cardiovascular risk scores and cognitive function (measured by a summary z-score, the NPZ-4) at a year 4 follow-up visit. RESULTS: Among 988 participants (mean age, 52 years; 20% women), mean 10-year ASCVD risk score at entry into the cohort was 6.8% (standard deviation [SD], 7.1%) and FRS was 13.1% (SD, 10.7%). In models adjusted only for cognitive function at entry, the ASCVD risk score significantly predicted year 4 NPZ-4 in the entire cohort and after stratification by sex (for every 1% higher ASCVD risk, year 4 NPZ-4 was lower by 0.84 [SD, 0.28] overall, P = .003; lower by 2.17 [SD, 0.67] in women, P = .001; lower by 0.78 [SD, 0.32] in men, P = .016). A similar relationship was observed between FRS and year 4 NPZ-4. In multivariable models, higher 10-year ASCVD risk and FRS predicted lower NPZ-4 in women. CONCLUSIONS: Baseline 10-year ASCVD risk and FRS predicted future cognitive function in older PLWH with well-controlled infection. Cardiovascular risk scores may help to identify PLWH, especially women, who are at risk for worse cognition over time.

The regional pattern of abnormal cerebrovascular reactivity in HIV-infected, virally suppressed women.

The purpose of this study was to assess whole brain and regional patterns of cerebrovascular reactivity (CVR) abnormalities in HIV-infected women using quantitative whole brain arterial spin labeling (ASL). We hypothesized that HIV-infected women would demonstrate decreased regional brain CVR despite viral suppression. This cross-sectional study recruited subjects from the Bay Area Women's Interagency Health Study (WIHS)-a cohort study designed to investigate the progression of HIV disease in women. In addition to conventional noncontrast cerebral MRI sequences, perfusion imaging was performed before and after the administration of intravenous acetazolamide. CVR was measured by comparing quantitative ASL brain perfusion before and after administration of intravenous acetazolamide. In order to validate and corroborate ASL-based whole brain and regional perfusion, phase-contrast (PC) imaging was also performed through the major neck vessels. FLAIR and susceptibility weighted sequences were performed to assess for white matter injury and microbleeds, respectively. Ten HIV-infected women and seven uninfected, age-matched controls were evaluated. Significant group differences were present in whole brain and regional CVR between HIV-infected and uninfected women. These regional differences were significant in the frontal lobe and basal ganglia. CVR measurements were not significantly impacted by the degree of white matter signal abnormality or presence of microbleeds. Despite complete viral suppression, dysfunction of the neurovascular unit persists in the HIV population. Given the lack of association between CVR and traditional imaging markers of small vessel disease, CVR quantification may provide an early biomarker of pre-morbid vascular disease.

Physical Activity Is Associated With Lower Odds of Cognitive Impairment in Women but Not Men Living With Human Immunodeficiency Virus Infection.

Background: Cardiovascular comorbidities are risk factors for human immunodeficiency virus (HIV)-associated cognitive impairment. Given differences in cardiometabolic risk profiles between women and men with HIV, we investigated whether associations between cardiometabolic risk factors and prevalent cognitive impairment differ by sex. Methods: Separate logistic regression models were constructed for women and men at entry into a prospective study of older persons with HIV (PWH) to assess the association of cardiometabolic and other risk factors with cognitive impairment. Results: Of 988 participants, 20% were women. Women had higher total cholesterol (194 vs 186 mg/dL; P = .027), hemoglobin A1c (5.9% vs 5.7%; P = .003), and body mass index (30.8 vs 27.4 kg/m2; P < .001) compared with men, and were less physically active (43% vs 55%; P = .005). In a multivariable model, physical activity was associated with lower odds of cognitive impairment in women (odds ratio, 0.35 [95% confidence interval, .15-.80]; P = .013) but not men. Conclusions: Physical activity may have a greater positive impact on cognitive health in women than in men with HIV. This finding should be confirmed in studies examining the longitudinal association between physical activity and incident cognitive impairment in PWH and the effect of interventions that increase physical activity on cognitive impairment in women with HIV.

Validation of the Intracerebral Hemorrhage Score in Uganda.

Background and Purpose- Rates of intracerebral hemorrhage (ICH) are estimated to be highest globally in sub-Saharan Africa. However, outcomes of ICH are poorly described and standard prognostic markers for ICH have not been validated in the region. Methods- We enrolled consecutive patients with computed tomography-confirmed ICH at a referral hospital in southwestern Uganda. We recorded demographic, clinical, and radiographic features of ICH, and calculated ICH scores. We fit Poisson regression models with robust variance estimation to determine predictors of case fatality at 30 days. Results- We enrolled 73 individuals presenting with computed tomography-confirmed ICH (mean age 60 years, 45% [33/73] female, and 14% [10/73] HIV-positive). The median ICH score was 2 (interquartile range, 1-3; range, 0-5). Case fatality at 30 days was 44% (32/73; 95% CI, 33%-57%). The 30-day case fatality increased with increasing ICH score of 0, 1, and 5 from 17%, 23%, to 100%, respectively. In multivariable-adjusted models, ICH score was associated with case fatality (adjusted relative risk, 1.48; 95% CI, 1.23-1.78), as were HIV infection (adjusted relative risk, 1.92; 95% CI, 1.07-3.43) and female sex (adjusted relative risk, 2.17; 95% CI, 1.32-3.59). The ICH score moderately improved with the addition of a point each for female sex and HIV serostatus (0.81 versus 0.73). Conclusions- ICH score at admission is a strong prognostic indicator of 30-day case fatality in Uganda. Our results support its role in guiding the care of patients presenting with ICH in the region.

Improvement in Diagnosis of Histoplasma Meningitis by Combined Testing for Histoplasma Antigen and Immunoglobulin G and Immunoglobulin M Anti-Histoplasma Antibody in Cerebrospinal Fluid.

Background: Central nervous system (CNS) histoplasmosis is a life-threatening condition and represents a diagnostic and therapeutic challenge. Isolation of Histoplasma capsulatum from cerebrospinal fluid (CSF) or brain tissue is diagnostic; however, culture is insensitive and slow growth may result in significant treatment delay. We performed a retrospective multicenter study to evaluate the sensitivity and specificity of a new anti-Histoplasma antibody enzyme immunoassay (EIA) for the detection of IgG and IgM antibody in the CSF for diagnosis of CNS histoplasmosis, the primary objective of the study. The secondary objective was to determine the effect of improvements in the Histoplasma galactomannan antigen detection EIA on the diagnosis of Histoplasma meningitis. Methods: Residual CSF specimens from patients with Histoplasma meningitis and controls were tested for Histoplasma antigen and anti-Histoplasma immunoglobulin G (IgG) and immunoglobulin M (IgM) antibody using assays developed at MiraVista Diagnostics. Results: A total of 50 cases and 157 controls were evaluated. Fifty percent of patients with CNS histoplasmosis were immunocompromised, 14% had other medical conditions, and 36% were healthy. Histoplasma antigen was detected in CSF in 78% of cases and the specificity was 97%. Anti-Histoplasma IgG or IgM antibody was detected in 82% of cases and the specificity was 93%. The sensitivity of detection of antibody by currently available serologic testing including immunodiffusion and complement fixation was 51% and the specificity was 96%. Testing for both CSF antigen and antibody by EIA was the most sensitive approach, detecting 98% of cases. Conclusions: Testing CSF for anti-Histoplasma IgG and IgM antibody complements antigen detection and improves the sensitivity for diagnosis of Histoplasma meningitis.

Detection of (1,3)-ß-d-Glucan in Cerebrospinal Fluid in Histoplasma Meningitis.

The diagnosis of central nervous system (CNS) histoplasmosis is often difficult. Although cerebrospinal fluid (CSF) (1,3)-ß-d-glucan (BDG) is available as a biological marker for the diagnosis of fungal meningitis, there are limited data on its use for the diagnosis of Histoplasma meningitis. We evaluated CSF BDG detection, using the Fungitell assay, in patients with CNS histoplasmosis and controls. A total of 47 cases and 153 controls were identified. The control group included 13 patients with a CNS fungal infection other than histoplasmosis. Forty-nine percent of patients with CNS histoplasmosis and 43.8% of controls were immunocompromised. The median CSF BDG level was 85 pg/ml for cases, compared to <31 pg/ml for all controls (P < 0.05) and 82 pg/ml for controls with other causes of fungal meningitis (P = 0.27). The sensitivity for detection of BDG in CSF was 53.2%, whereas the specificity was 86.9% versus all controls and 46% versus other CNS fungal infections. CSF BDG levels of ≥80 pg/ml are neither sensitive nor specific to support a diagnosis of Histoplasma meningitis.

Stroke in Human Immunodeficiency Virus-infected Individuals in Sub-Saharan Africa (SSA): A Systematic Review.

BACKGROUND: Human immunodeficiency virus (HIV) infection is associated with worse outcomes after stroke, but this association is less well-described in sub-Saharan Africa (SSA). We reviewed literature on stroke among people living with HIV (PLWH) in SSA. METHODS: We systematically reviewed published literature for original clinical stroke studies conducted in SSA that included PLWH. We included studies that reported data on presenting characteristics, risk factors, and/or outcomes after stroke. RESULTS: Seventeen studies (N = 478) met inclusion criteria. At the time of stroke presentation, PLWH had a median age ranging from 32 to 43 years. Subjects had low CD4 counts (median CD4, 108-225 cells/µl), and most were antiretroviral therapy-naïve. Fever, seizures, and concurrent opportunistic infections were common at presentation. Ischemic stroke accounted for up to 96% of strokes, which were mostly located in the anterior circulation territory. In studies comparing PLWH with HIV-uninfected individuals, PLWH had more frequent coagulopathy, greater stroke severity, (72% versus 36% National Institutes of Health Stroke Scale >13, P = .02), longer hospital length of stay (30.5 versus <10 days), and a higher 30-day mortality rate (23% versus 10.5%, P = .007). CONCLUSION: Stroke in PLWH in SSA occurs at a young age, in those with advanced disease, and is associated with worse outcomes than in HIV-uninfected comparators. Stroke in young individuals in the region should prompt HIV testing, and ongoing efforts to promote early antiretroviral therapy initiation might also help decrease stroke incidence, morbidity, and mortality in the region.

Sex Matters in Neuroinfectious Diseases.

Although sex and gender have a major impact on the susceptibility and immunologic response to infectious diseases, these factors are often neglected. Identifying the mechanisms underlying sex-based differences in infectious diseases will facilitate the rational design and implementation of preventive and therapeutic strategies that reduce risk and improve outcomes for women and men. In this article, we discuss two examples in neuroinfectious diseases of how sex matters: (1) the heightened risk of cerebrovascular disease in women living with HIV infection and (2) the implications of Zika virus infection on sexual and reproductive health and vaccine development for women.

Greater Risk of Stroke of Undetermined Etiology in a Contemporary HIV-Infected Cohort Compared with Uninfected Individuals.

BACKGROUND: Although ischemic stroke risk is increased among people living with HIV infection, little is known about the epidemiology of ischemic stroke subtypes in contemporary HIV-infected cohorts. We examined the distribution of ischemic stroke subtypes among predominantly treated HIV-infected individuals to determine if and how the distribution differs from that of the general population. METHODS: We studied 60 HIV-infected and 60 HIV-uninfected adults with a history of first-ever ischemic stroke between 2000 and 2012. Ischemic strokes were classified as 1 of 5 subtypes based on established criteria. We used multinomial logistic regression models to compare the relative frequency of ischemic stroke subtypes by HIV status. RESULTS: Large artery atherosclerosis (23%) and stroke of undetermined etiology (23%) were the most common stroke subtypes among HIV-infected individuals. The most recent plasma HIV viral load before the stroke event differed by subtype, with a median undetectable viral load for individuals with large artery stroke and stroke of undetermined etiology. Using cardioembolic stroke as the reference subtype, HIV-infected individuals were at higher proportional risk of stroke of undetermined etiology compared with uninfected individuals (relative risk ratio [RRR]: 8.6, 95% confidence interval [CI]: 1.2-63.7, P = .04). Among HIV-infected individuals with virologically suppressed infection, we observed a trend toward a greater proportion of strokes attributable to large artery atherosclerosis (RRR: 6.7, 95% CI: .8-57.9, P = .08). CONCLUSIONS: HIV-infected individuals may be at greater proportional risk of stroke of undetermined etiology compared with uninfected individuals. Further investigation is warranted to confirm this finding and determine underlying reasons for this greater risk.

Identification of cellular targets of a series of boron heterocycles using TIPA II-A sensitive target identification platform.

One of the hurdles in the discovery of antibiotics is the difficulty of linking antibacterial compounds to their cellular targets. Our laboratory has employed a genome-wide approach of over-expressing essential genes in order to identify cellular targets of antibacterial inhibitors. Our objective in this project was to develop and validate a more sensitive disk diffusion based platform of target identification (Target Identification Platform for Antibacterials version 2; TIPA II) using a collection of cell clones in an Escherichia coli mutant (AS19) host with increased outer membrane permeability. Five known antibiotics/inhibitors and 28 boron heterocycles were tested by TIPA II assay, in conjunction with the original assay TIPA. The TIPA II was more sensitive than TIPA because eight boron heterocycles previously found to be inactive to AG1 cells in TIPA assays exhibited activity to AS19 cells. For 15 boron heterocycles, resistant colonies were observed within the zones of inhibition only on the inducing plates in TIPA II assays. DNA sequencing confirmed that resistant clones harbor plasmids with fabI gene as insert, indicating that these boron heterocycles all target enoyl ACP reductase. Additionally, cell-based assays and dose response curved obtained indicated that for two boron heterocycle inhibitors, the fabI cell clone in AG1 (wild-type) host cells exhibited at least 11 fold more resistance under induced conditions than under non-induced conditions. Moreover, TIPA II also identified cellular targets of known antibacterial inhibitors triclosan, phosphomycin, trimethoprim, diazaborine and thiolactomycin, further validating the utility of the new system.