Neuropsychological abnormalities in AIDS and asymptomatic HIV seropositive patients

Chronic Tobacco-Smoking on Psychopathological Symptoms, Impulsivity and Cognitive Deficits in HIV-Infected Individuals

HIV-infected individuals (HIV+) has 2-3 times the rate of tobacco smoking than the general population, and whether smoking may lead to greater psychiatric symptoms or cognitive deficits remains unclear. We evaluated the independent and combined effects of being HIV+ and chronic tobacco-smoking on impulsivity, psychopathological symptoms and cognition. 104 participants [27 seronegative (SN)-non-Smokers, 26 SN-Smokers, 29 HIV+ non-Smokers, 22 HIV+ Smokers] were assessed for psychopathology symptoms (Symptom Checklist-90, SCL-90), depressive symptoms (Center for Epidemiologic Studies-Depression Scale, CES-D), impulsivity (Barratt Impulsiveness Scale, BIS), decision-making (The Iowa Gambling Task, IGT, and Wisconsin Card Sorting Test, WCST), and cognition (seven neurocognitive domains). Both HIV+ and Smoker groups had higher SCL-90 and CES-D scores, with highest scores in HIV+ Smokers. On BIS, both HIV+ and Smokers had higher Total Impulsiveness scores, with higher behavioral impulsivity in Smokers, highest in HIV+ Smokers. Furthermore, across the four groups, HIV+ Smokers lost most money and made fewest advantageous choices on the IGT, and had highest percent errors on WCST. Lastly, HIV+ had lower z-scores on all cognitive domains, with the lowest scores in HIV+ Smokers. These findings suggest that HIV-infection and chronic tobacco smoking may lead to additive deleterious effects on impulsivity, psychopathological (especially depressive) symptoms and cognitive dysfunction. Although greater impulsivity may be premorbid in HIV+ and Smokers, the lack of benefits of nicotine in chronic Smokers on attention and psychopathology, especially those with HIV-infection, may be due to the negative effects of chronic smoking on dopaminergic and cardio-neurovascular systems. Tobacco smoking may contribute to psychopathology and neurocognitive disorders in HIV+ individuals.

Neuropsychological Dysfunction in HIV Infection:A Review

FIfty-six studies which used neuropsychological tests to investigate areas of function affected by central nervous system dysfunction in HIV were reviewed. Only studies which compared the performance of HIV + subjects to HIV - controls using analysis of variance techniques were included. The results are examined in terms of broad neuropsychological function domains, and are examined separately for asymptomatic and symptomatic subjects. Studies which did and did not find significant differences between HIV + and HIV - subjects were compared in terms of various confounding factors such as risk groups, number of tests, sample size and subject characteristics. There was evidence for some dysfunction among subjects who are otherwise asymptomatic in the areas of verbal memory (27% of studies), executive function (43%), motor performance (20%) and information processing (44%). Studies of subjects with more advanced HIV infection showed consistent evidence of abnormal functioning in the areas of verbal (48% of studies) and visual memory (43%), executive functioning (71%), complex attention (62%), motor performance (37%) and information processing (69%). These deficits occurred prior to the onset of clinically apparent dementia. There were no consistent significant differences between studies which did and did not find significant differences between HIV + and HIV - subjects in terms of most of the confounding variables investigated, although studies of ASX subjects were more likely to find differences between HIV + subjects and controls with larger neuropsychological test battereies. However, much of the variation in results due to the neuropsychological tests used. In many cases, tests which relied on functions with a frontal lobe component were more likely to find significant results.

Cognitive Performance in Men and Women Infected with HIV-1

Introduction. Very few studies have examined the neuropsychological performance of HIV-positive women, and even fewer have attempted a comparison of cognitive functioning by gender. The aim of this study was to describe the nature of the neuropsychological performance of HIV seropositive patients by gender. Methods. A clinical sample made up of 151 subjects was recruited to participate in this study. All of the subjects underwent the same assessment process, consisting of a neuropsychological evaluation and an interview to gather sociodemographic, toxicological, and clinical data. Results and Discussion. Despite the fact that men obtained higher scores in visual memory, attention/psychomotor speed, and abstract reasoning/verbal intelligence, these differences were not statistically significant. In contrast, significant differences were found depending on subjects' serological status. Seropositive participants' neuropsychological performance was significantly lower than that of the seronegative participants in all of the areas assessed as follows: (1) visual memory; (2) attention/psychomotor speed; (3) abstract reasoning/verbal intelligence; (4) verbal memory for texts; (5) verbal memory for digits and words. Conclusions. The results from this study reveal no significant gender differences in the cognitive performance of patients infected with HIV-1.

Neuropsychological impairment and gender differences in HIV-1 infection

AIMS

Research into neuropsychological consequences of HIV has focused mainly on male subjects, and therefore very little is known about the disease in female subjects and, of course, about gender differences. The aim of the present research was therefore to investigate neuropsychological impairment rates and pattern in HIV male and female patients, with regard to the study of gender differences in tasks assessing attention, memory for texts, digits and words, psychomotor speed, verbal intelligence and abstract reasoning.

METHODS

A clinical sample was recruited consisting of 122 subjects, divided into four groups: (i) 57 HIV+ men; (ii) 31 HIV+ women; (iii) 18 HIV- men and (iv) 16 HIV- women. All the subjects had more than 18 years, being the average of age of 34.08 for men and 33.35 for women. The evaluation of each subject consisted of a semistructured interview investigating sociodemographic, clinical and toxicological aspects and a neuropsychological assessment, with a battery of tests specifically selected for this study and chosen for their validity and because they have been shown to be sensitive to neuropsychological impairment in HIV-infected patients in other studies.

RESULTS

None of HIV- male and female groups fulfilled impairment criteria. Regarding the HIV+ group, a rate of neuropsychological impairment of 51.9% was obtained for the men and 54.8% for the women, but there were no significant differences between groups. Nevertheless, were detected significant differences in neuropsychological impairment rates between HIV+ and HIV- women, and also between HIV+ and HIV- men. Although HIV+ women presented multiple factors that could increase their neuropsychological vulnerability to the effects of HIV, HIV+ men had the same probability of having neuropsychological impairment as HIV+ women.

CONCLUSIONS

A different neuropsychological impairment pattern was detected between genders: while HIV+ men had greater impairment in visual memory, attention, psychomotor speed and abstract reasoning, HIV+ women had greater impairment on attention, psychomotor speed and verbal memory for texts.

Copolymer-1 induces adaptive immune anti-inflammatory glial and neuroprotective responses in a murine model of HIV-1 encephalitis

Copolymer-1 (COP-1) elicits neuroprotective activities in a wide range of neurodegenerative disorders. This occurs, in part, by adaptive immune-mediated suppression of microglial inflammatory responses. Because HIV infection and immune activation of perivascular macrophages and microglia drive a metabolic encephalopathy, we reasoned that COP-1 could be developed as an adjunctive therapy for disease. To test this, we developed a novel animal model system that reflects HIV-1 encephalitis in rodents with both innate and adaptive arms of the immune system. Bone marrow-derived macrophages were infected with HIV-1/vesicular stomatitis-pseudotyped virus and stereotactically injected into the basal ganglia of syngeneic mice. HIV-1 pseudotyped with vesicular stomatitis virus envelope-infected bone marrow-derived macrophages induced significant neuroinflammation, including astrogliosis and microglial activation with subsequent neuronal damage. Importantly, COP-1 immunization reduced astro- and microgliosis while diminishing neurodegeneration. Hippocampal neurogenesis was, in part, restored. This paralleled reductions in proinflammatory cytokines, including TNF-alpha and IL-1beta, and inducible NO synthase, and increases in brain-derived neurotrophic factor. Ingress of Foxp3- and IL-4-expressing lymphocytes into brains of COP-1-immunized animals was observed. We conclude that COP-1 may warrant therapeutic consideration for HIV-1-associated cognitive impairments.

Neuropsychological Impairment Among Asymptomatic HIV-Positive Former Intravenous Drug Users

OBJECTIVE

To evaluate the influence of human immunodeficiency virus (HIV) infection and situation of drug consumption on neuropsychological impairment in asymptomatic HIV-positive (HIV+) former intravenous drug users (IVDUs) of Spanish nationality.

BACKGROUND

Currently, we have no data about neuropsychological impairment in asymptomatic HIV+ IVDUs taking into account different situations of drug consumption.

METHOD

A neuropsychological evaluation was made of four groups of IVDUs: 33 abstinent HIV+ IVDUs, 21 methadone-maintained HIV+ IVDUs, 27 abstinent HIV-negative (HIV-) IVDUs, and 21 methadone-maintained HIV- IVDUs. Their neuropsychological impairment rates were determined taking as a reference the performance of 23 HIV- subjects without history of drug abuse.

RESULTS

The rate of neuropsychological impairment of methadone-maintained HIV+ patients (48%) and that of those in abstinence (24%) is greater than that of HIV- subjects in a similar condition (19% and 11%). The impairment rate of the methadone-maintained HIV+ group is significantly greater than that of the abstinent HIV+. Methadone-maintained HIV+ subjects with neuropsychological impairment have fewer education years than those not impaired; likewise, the percentages of subjects with significant immunodepression, detectable viral load, and without antiretroviral treatments are higher among methadone-maintained subjects with neuropsychological impairment.

CONCLUSIONS

This study emphasizes the association of asymptomatic HIV infection with neuropsychological impairment in IVDUs and reveals the importance of the drug consumption situation in relation to this risk, being methadone-maintained IVDUs more likely to suffer from it. This fact seems to be related to the worsening of the infection and its treatment and to educational level.

Host response and dysfunction in the CNS during chronic simian immunodeficiency virus infection

CNS abnormalities can be detected during chronic human immunodeficiency virus (HIV) infection, before the development of opportunistic infections or other sequelae of immunodeficiency. However, although end-stage dementia caused by HIV has been linked to the presence of infected and activated macrophages and microglia in the brain, the nature of the changes resulting in the motor and cognitive disorders in the chronic stage is unknown. Using simian immunodeficiency virus-infected rhesus monkeys, we sought the molecular basis for CNS dysfunction. In the chronic stable stage, nearly 2 years after infection, all animals had verified CNS functional abnormalities. Both virus and infiltrating lymphocytes (CD8+ T-cells) were found in the brain. Molecular analysis revealed that the expression of several immune response genes was increased, including CCL5, which has pleiotropic effects on neurons as well as immune cells. CCL5 was significantly upregulated throughout the course of infection, and in the chronic phase was present in the infiltrating lymphocytes. We have identified an altered state of the CNS at an important stage of the viral-host interaction, likely arising to protect against the virus but in the long term leading to damaging processes.

The nervous system in early HIV infection: a prospective study through 7 years

In this study 28 patients with early stage HIV infection (CD4 >280 x 10(6)/l) were subjected to yearly examinations of the nervous system up to 7 years in order to detect any deterioration. Clinical neurological as well as neuropsychological performance was evaluated. The patients also underwent yearly neurophysiological tests (digital EEG, visual evoked potentials, somatosensory evoked potentials, auditory evoked potentials P300 and electroneurography). Every other year, SPECT with (99m)Tc-D,L-hexamethylpropylene amine oxime and brain MRI were performed. Originally, 38 patients were included in the study but only the results of 28 patients who complied with three of more yearly check-ups are presented. The results of yearly investigations of cerebrospinal fluid (CSF) have been presented earlier [Eur J Neurol4 (1997) 1]. All the patients showed signs of HIV in the CSF. Yet, no major deterioration in the neurological, psychological performance, neurophysiological or neuroimaging examinations could be discerned.

ERPs differ from neurometric tests in assessing HIV-associated cognitive deficit

The onset and time-course of HIV-associated cognitive deficits are not well established. The present experiment compared physiological and neurometric assessments of cognitive decline in HIV-asymptomatic, HIV-symptomatic, and HIV-negative control adult women. The P3 component of standard auditory, event-related electrical potentials of the brain (ERP) and standard neurometric (pencil and paper) test scores were recorded. The P3 ERP measures differentiated both of the clinical HIV groups from the control group. In contrast, the neurometric measures were more sensitive to the difference in cognitive decline between the two clinical groups. It is concluded that both P3 ERP measures and standard neurometric tests are individually useful and complementary for tracking cognitive decline in the diagnosis and treatment of opportunistic HIV-associated central nervous system impairments.

Longitudinal analysis of behavioral, neurophysiological, viral and immunological effects of SIV infection in rhesus monkeys

A model is proposed in which a neurovirulent, microglial-passaged, simian immunodeficiency virus (SIV) is used to produce central nervous system (CNS) pathology and behavioral deficits in rhesus monkeys reminiscent of those seen in humans infected with human immunodeficiency virus (HIV). The time course of disease progression was characterized by using functional measures of cognition and motor skill, as well as neurophysiologic monitoring. Concomitant assessment of immunological and virological parameters illustrated correspondence between impaired behavioral performance and viral pathogenesis. Convergent results were obtained from neuropathological findings indicative of significant CNS disease. In ongoing studies, this SIV model is being used to explore the behavioral sequelae of immunodeficiency virus infection, the viral and host factors leading to neurologic dysfunction, and to begin testing potential therapeutic agents.

Brain proton magnetic resonance spectroscopy in HIV-related encephalopathy: identification of evolving metabolic patterns in relation to dementia and therapy

Proton MRS has proved useful in the early diagnosis of HIV-related encephalopathy. The modifications of brain metabolism in HIV-related encephalopathy can be classified according to different metabolic patterns (Vion-Dury J et al. CR Acad Sci 1994;317:833-840). The present study describes the relative occurrence of these patterns and evaluates their evolution under zidovudine treatment. We have examined 112 HIV patients--35 neuroasymptomatic patients and 77 patients with ADC (AIDS dementia complex)--with localized proton MRS, using the PRESS 135-msec sequence. We have found the same metabolic modifications in N-acetylaspartate and choline-containing compounds as described in the literature. In addition, 14% of HIV patients with normal MRI displayed abnormal MRS, whatever their neurological status. The MRS-added diagnostic value in neuroasymptomatic patients reaches 30 %. The occurrence of undifferentiated (modification of NAA/Cho ratio only) and Cho (mainly an increase in choline signal) patterns is not significantly different in neuroasymptomatic and ADC patients. The NAA pattern (mainly a significant loss of NAA) is more frequent in ADC patients. Only ADC patients display the double pattern (with a significant increase in choline signal and a significant loss of NAA). Quantitated cerebral atrophy (bifrontal ratio) is related to the occurrence of NAA loss (in NAA and double patterns). An MRS follow-up study of 11 HIV patients showed that the clinical outcome was favorable after a 1000-mg/day zidovudine treatment in patients displaying an NAA pattern whereas this treatment had no effect on the patients displaying the Cho pattern. Consequently, MRS appears to be of great interest in predicting responsiveness to antiretroviral drugs and detecting early any resistance to treatment.

Cerebral metabolic alterations in human immunodeficiency virus-related encephalopathy detected by proton magnetic resonance spectroscopy. Comparison between sequences using short and long echo times

RATIONALE AND OBJECTIVES

The aim of this study is to evaluate comparatively the metabolic information afforded by proton magnetic resonance (MR) spectroscopy with stimulated-echo acquisition mode (STEAM) (echo time [TE], 20 mseconds) and point-resolved spectroscopy sequence (PRESS) (TE, 135 mseconds) spectra in HIV-related encephalopathy.

METHODS

Sixty-three human immunodeficiency virus (HIV) patients and 8 controls were examined by single-voxel proton MR spectroscopy at 1.5 tesla, using both PRESS (TE, 135 mseconds) and STEAM (TE, 20 mseconds) sequences performed during the same MR examination, in the same volume of interest. Cerebral atrophy was quantitated using bicaudate ratio (BCR) and bifrontal ratio (BFR).

RESULTS

With the STEAM (TE, 20 mseconds) spectra, mean N-acetylaspartate (NAA)/choline (Cho) and NAA/creatine and phosphocreatine (Cr-PCr) ratios are reduced in acquired immunodeficiency syndrome (AIDS) dementia complex (ADC) patients but not in neuroasymptomatics. The proportion of inositol signal is increased, that of NAA decreased in ADC patients. NAA/Cho and NAA/ Cr-PCr mean values measured with PRESS (TE, 135 mseconds) spectra are significantly reduced in ADC and neuroasymptomatic patients. Bifrontal ratio only correlates with NAA/Cr-PCr and NAA/Cho measured on the PRESS spectrum. PRESS (TE, 135 mseconds) spectra allow a definition of different metabolic patterns in HIV-related encephalopathy. At last, no correlation has been found between the NAA raw signals measured on the PRESS (TE, 135 mseconds) and STEAM (TE, 20 mseconds) spectra obtained in the same MR examination.

CONCLUSIONS

STEAM (TE, 20 mseconds) spectra provide more metabolic information-namely an evaluation of glial-neuronal status-than PRESS (TE, 135 mseconds) spectra, which afford a metabolic classification of the HIV-related encephalopathy. Because both sequences afford a similar diagnostic gain, MR spectroscopy examination probably requires spectrum acquisition with both sequences.

Immunological markers of disease progression in patients infected with the human immunodeficiency virus

Identification of inexpensive and technically simple immunological tests useful in predicting the progression to AIDS in human immunodeficiency virus (HIV)-infected patients would be especially welcome in developing countries, in which 80% of HIV-infected patients reside and health budgets are low. In the current study, we evaluated CD4+ and total lymphocyte counts and the concentrations in serum of beta 2-microglobulin, p24 antigen, and immunoglobulin A (IgA) as predictors of disease progression in 74 Panamanian HIV-positive patients and 50 HIV-negative healthy individuals. Total lymphocyte and CD4(+)-cell counts for AIDS patients (1,451 +/- 811 cells/microliters, P < 0.001, and 238 +/- 392 cells/microliters, P < 0.0001, respectively and asymptomatic patients (2,393 +/- 664 cells/microliters, P > 0.05, and 784 +/- 475 cells/microliters, P < 0.001, respectively) were lower than those observed for healthy subjects (2,596 +/- 631 cells/microliters and 1,120 +/- 296 cells/microliters, respectively). The levels of beta 2-microglobulin and IgA in serum were significantly elevated in patients with AIDS (5.7 +/- 3.6mg/liter, P < 0.001, and 541 +/- 265 mg/dl, P < 0.0002, respectively) and asymptomatic infected subjects (3.4 +/- 2.1 mg/liter, P = 0.001, and 436 +/- 216 mg/dl, P < 0.0001, respectively) compared with the levels in healthy subjects (2.2 +/- 0.7 mg/liter and 204 +/- 113 mg/dl, respectively). Nonstatistically significant differences (P > 0.05) for concentrations of p24 antigen between asymptomatic infected patients (29 +/- 13 pg/ml) and AIDS patients (40 +/- 23 pg/ml) were observed. Total lymphocyte counts of 1,750 cells/microliters or less, CD4 counts of 200 cells/microliters or less, beta 2-microglobulin concentrations in serum of 4 mg/liter or higher, concentrations of IgA in serum of 450 mg/dl or higher, and the presence in serum of p24 antigen were correlated with elevated risks for developing AIDS. Monitoring both total lymphocytes and beta 2-microglobulin identified 91% of the AIDS patients; these assays may allow reductions in the annual number of CD4(+)-cell evaluations and the costs associated with monitoring both total lymphocytes and beta 2-microglobulin identified 91% of the AIDS patients; these assays may allow reductions in the annual number of CD4(+)-cell evaluations and the costs associated with monitoring the immune status of HIV-positive patients.

Cognitive and emotional deficits in early stages of HIV infection: an event-related potentials study

1. In order to inventory different Event-Related Potentials (ERP) modifications in HIV-infection the authors have evaluated 23 HIV-positive subjects and 12 HIV-negative subjects. ERP were recorded during an auditory oddball task. 2. Electrophysiological results showed that the latency of the N100 component of the ERP was significantly increased in HIV-positive subjects compared to the HIV-negative subjects. The latency of the N200 component of the ERP showed a similar tendency which just failed to reach significance when considering HIV-positive subjects vs HIV negative subjects. This result was in agreement with the literature which reported increased latencies in HIV infection. 3. Considering all subjects the authors have observed a correlation between the amplitude of the P300 and the emotional deficit. This correlation was stronger in subjects who presented an emotional deficit and was independent of any other psychopathological symptom. 4. The use of ERP appeared to be a sensitive technique to detect subclinical manifestations in HIV asymptomatic subjects and therefore would help to identify subjects at higher risk for developing cognitive impairments.

Neuropsychological deficits in tests of executive function in asymptomatic and symptomatic HIV-1 seropositive men

There has been much debate about the exact nature and time of onset of the cognitive impairments associated with infection by the human immunodeficiency virus type 1 (HIV-1). Studies to date have not reached consistent conclusions. The present study comprised 22 asymptomatic and 18 symptomatic HIV-1 seropositive men, whose only risk factor for contraction of the virus was sexual intercourse, and 18 seronegative controls matched for age and IQ. Subjects were given computerized neuropsychological tests from the CANTAB battery, which assessed visuospatial memory, attention and executive function. Both the asymptomatic and the symptomatic HIV-1 seropositive subjects showed a selective pattern of deficits relative to the controls. In addition, the seropositive subjects were subtly but significantly impaired on tests of executive function but unimpaired on certain tests of visual memory. This finding supports an hypothesis that frontostriatal dysfunction occurs in HIV-1 infected individuals prior even to the expression of clinical symptoms.

Neuronal expression of human immunodeficiency virus type 1 env proteins in transgenic mice: distribution in the central nervous system and pathological alterations

It is now well documented that human immunodeficiency virus type 1 (HIV-1) induces encephalopathy in patients with AIDS. In vitro studies have implicated the envelope protein (gp120) as a factor which causes neuronal death. To better evaluate the role and elucidate the mechanisms of gp120 neurotoxicity, we have developed transgenic mice carrying a segment of the HIV-1 genome that expresses the viral gp160 protein under the control of the human neurofilament light gene promoter. In two separate lines of transgenic mice, the Env protein was found to be expressed in several nuclei of the brain stem and in the anterior horns of the spinal cord. The two lines showed identical patterns of Env expression. Neuropathological evaluation revealed numerous abnormal dendritic swellings in the immunostained motor neuron structures. Large and numerous neuritic swellings were also prominent in the nucleus gracilis and in the gracilis and cuneate fascicles. In addition, reactive astrocytosis was observed in several immunoreactive areas of the central nervous system. These transgenic mice offer a unique model to further investigate the role of HIV-1 Env protein in neuronal toxicity and to help elucidate the mechanisms that are involved.