A Quantitative MRI Study of the Basal Ganglia in Depression in HIV Seropositive Men

HIV (Human Immunodeficiency Virus) infection is associated with high rates of depressive symptomatology. There is evidence that such infection is associated with damage to the basal ganglia. It has also been suggested that the basal ganglia are implicated in the aetiology of affective disorders.

OBJECTIVE

This study examined the association between basal ganglia atrophy and depression in HIV seropositive men. We hypothesized that depressed HIV seropositive patients would have smaller basal ganglia compared with nondepressed HIV positive comparison subjects.

METHOD

Using quantitative magnetic resonance imaging (MRI) techniques we compared for the basal ganglia volumes of sixteen depressed, and sixteen group-matched nondepressed HIV seropositive homosexual men.

RESULTS

We found no significant difference in basal ganglia volumes between the two groups.

CONCLUSIONS

We suggest that depression, at least in the early stages of HIV infection, is not associated with basal ganglia atrophy.

Brain morphometric correlates of metabolic variables in HIV: the CHARTER study

Obesity and other metabolic variables are associated with abnormal brain structural volumes and cognitive dysfunction in HIV-uninfected populations. Since individuals with HIV infection on combined antiretroviral therapy (CART) often have systemic metabolic abnormalities and changes in brain morphology and function, we examined associations among brain volumes and metabolic factors in the multisite CNS HIV AntiRetroviral Therapy Effects Research (CHARTER) cohort, cross-sectional study of 222 HIV-infected individuals. Metabolic variables included body mass index (BMI), total blood cholesterol (C), low- and high-density lipoprotein C (LDL-C and HDL-C), blood pressure, random blood glucose, and diabetes. MRI measured volumes of cerebral white matter, abnormal white matter, cortical and subcortical gray matter, and ventricular and sulcal CSF. Multiple linear regression models allowed us to examine metabolic variables separately and in combination to predict each regional volume. Greater BMI was associated with smaller cortical gray and larger white matter volumes. Higher total cholesterol (C) levels were associated with smaller cortex volumes; higher LDL-C was associated with larger cerebral white matter volumes, while higher HDL-C levels were associated with larger sulci. Higher blood glucose levels and diabetes were associated with more abnormal white matter. Multiple atherogenic metabolic factors contribute to regional brain volumes in HIV-infected, CART-treated patients, reflecting associations similar to those found in HIV-uninfected individuals. These risk factors may accelerate cerebral atherosclerosis and consequent brain alterations and cognitive dysfunction.

Characterizing HIV medication adherence for virologic success among individuals living with HIV/AIDS: Experience with the CNS HIV Antiretroviral Therapy Effects Research (CHARTER) cohort

Antiretroviral therapy (ART) has changed HIV related illness from terminal to chronic by suppressing viral load which results in immunologic and clinical improvement. Success with ART is dependent on optimal adherence, commonly categorized as >95%. As medication type, class and frequency of use continue to evolve, we assessed adherence levels related to viral suppression. Using a cross-sectional analysis with secondary data (n = 381) from an ongoing multi-site study on impact of ART on the Central Nervous System (CNS), we compared self-reported adherence rates with biological outcomes of HIV-RNA copies/ml, and CD4 cell/mm3. Adherence to ART measures included taking all prescribed medication as directed on schedule and following dietary restrictions. While depression was a barrier to adherence, undetectable viral suppression was achieved at pill adherence percentages lower than 95%. Practice, research and policy implications are discussed in the context of patient-, provider-, and system-level factors influencing adherence to ART.

Defining neurocognitive impairment in HIV: deficit scores versus clinical ratings

Because HIV-related neurocognitive impairment is usually mild and variable, clinical ratings (CR) and global deficit scores (GDS) are recommended for detecting HIV-associated neurocognitive disorders (HAND). The CR approach requires impairment in at least two ability domains while the GDS considers number and severity of impairments across all measures. We examined classification agreement and clinical correlates of the two methods. Neurocognitive functioning of 1574 HIV-infected participants was assessed via a comprehensive, seven-domain neuropsychological battery. Global neurocognitive impairment was defined for each participant independently by CR and GDS. Participants were classified into four categories (Dually-normal, [impaired by] CR-only, [impaired by] GDS-only, or Dually-impaired). There was 83% concordance between CR and GDS classifications; in total, 56% of participants were deemed impaired by CR and 41% were classified as impaired by GDS. Impairment by GDS virtually guaranteed CR impairment, but 16% of participants were additionally classified as impaired only by CR. As compared to Dually-normal participants, those classified as Dually and CR-only impaired were more likely to have AIDS, have more severe co-occurring conditions, have more severe depressive symptoms, be unemployed, and have more everyday functioning complaints (ps < .05). Impairment classifications of the two methods were in high agreement; however, more people were classified as impaired using the CR approach compared to the GDS approach. Those impaired according to CR-only showed fewer neurocognitive and functional deficits than the Dually-impaired participants, but more of these deficits than Dually-normal participants. The CR approach may be most appropriate for detecting more subtle forms of neurocognitive impairment. Clinicians and researchers should recognize the strengths and weaknesses of each method when evaluating neurocognitive complications in HIV.

Immune reconstitution inflammatory syndrome in natalizumab-associated PML

OBJECTIVE

To study the outcome of patients with multiple sclerosis (MS) and with natalizumab-associated progressive multifocal leukoencephalopathy (PML) and immune reconstitution inflammatory syndrome (IRIS).

METHODS

MedWatch reports from Biogen-Idec (manufacturer of natalizumab, Tysabri(®)) were reviewed which comprised all 42 cases of natalizumab-related PML cases since its reintroduction until March 2010.

RESULTS

All except 2 patients with natalizumab-related PML were managed by discontinuation of natalizumab and plasmapheresis/immunoadsorption (PLEX/IA). Seventeen patients had contrast enhancement of PML lesions on neuroimaging at the time of diagnosis before withdrawal/removal of natalizumab (early-PML-IRIS) and 23 patients developed contrast enhancement only after withdrawal/removal of natalizumab (late-PML-IRIS). All patients developed IRIS. IRIS was defined as worsening of neurologic deficits during the immune reconstitution following discontinuation of natalizumab, corroborated by inflammatory changes on neuroimaging. Following PLEX/IA, JC viral load in CSF increased by >10 fold in those with early-PML-IRIS but <2 fold in late-PML-IRIS. IRIS developed earlier and was more severe in early-PML-IRIS (p < 0.05). At the last follow-up, all patients had worse EDSS scores but this was higher in patients with early-PML-IRIS compared to those with late-PML-IRIS (p > 0.05). Mortality was comparable between the 2 groups, 29.4 ± 11% vs 21.7 ± 8.8%. Corticosteroid therapy during IRIS was associated with better Expanded Disability Status Scale outcome, p < 0.05.

CONCLUSION

Early immunologic rebound in natalizumab-associated PML has worse survival and neurologic outcome. PLEX/IA may accelerate IRIS and its impact on the final outcome is unclear. Corticosteroid therapy provides a modest benefit and needs to be systemically studied in a controlled manner in the management of natalizumab-associated PML-IRIS.

Fulminant encephalopathy with basal ganglia hyperintensities in HIV-infected drug users

OBJECTIVE

To define a clinical syndrome associated with active drug abuse in HIV-infected individuals.

METHODS

We performed a retrospective review to identify individuals treated at the Johns Hopkins Hospital from 1993 to 2008 who were HIV-infected and were actively abusing drugs and had bilateral basal ganglia lesions on MRI. They were identified using a key word search in the radiology database, autopsy database, and the Moore HIV clinic database. Clinical, laboratory, and radiographic findings were correlated to define the syndrome.

RESULTS

Ten individuals were identified who presented with a change in mental status or seizures, used cocaine or cocaine with heroin, had uncontrolled HIV infection (>190,000 copies/mL of plasma), elevated CSF protein (63-313 mg/dL), and diffuse hyperintense bilateral basal ganglia lesions on imaging. The majority of patients (8/10) had renal failure and despite supportive therapy most (7/9) ultimately died (median survival 21 days). Postmortem examination in one individual showed the presence of overwhelming microglial activation in the basal ganglia. The 2 surviving individuals were started on combined antiretroviral therapy (CART) during hospitalization.

CONCLUSION

We describe a unique clinical syndrome of a fulminant encephalopathy associated with primarily basal ganglia involvement in HIV-infected drug abusers. This syndrome is a rare but serious condition that is associated with a high mortality rate. Early CART institution may be useful and neuroprotective in this disorder, although this requires further investigation.

HIV-associated neurocognitive disorders persist in the era of potent antiretroviral therapy: CHARTER Study

OBJECTIVES

This is a cross-sectional, observational study to determine the frequency and associated features of HIV-associated neurocognitive disorders (HAND) in a large, diverse sample of infected individuals in the era of combination antiretroviral therapy (CART).

METHODS

A total of 1,555 HIV-infected adults were recruited from 6 university clinics across the United States, with minimal exclusions. We used standardized neuromedical, psychiatric, and neuropsychological (NP) examinations, and recently published criteria for diagnosing HAND and classifying 3 levels of comorbidity (minimal to severe non-HIV risks for NP impairment).

RESULTS

Fifty-two percent of the total sample had NP impairment, with higher rates in groups with greater comorbidity burden (40%, 59%, and 83%). Prevalence estimates for specific HAND diagnoses (excluding severely confounded cases) were 33% for asymptomatic neurocognitive impairment, 12% for mild neurocognitive disorder, and only 2% for HIV-associated dementia (HAD). Among participants with minimal comorbidities (n = 843), history of low nadir CD4 was a strong predictor of impairment, and the lowest impairment rate on CART occurred in the subset with suppressed plasma viral loads and nadir CD4 ≥200 cells/mm(3) (30% vs 47% in remaining subgroups).

CONCLUSIONS

The most severe HAND diagnosis (HAD) was rare, but milder forms of impairment remained common, even among those receiving CART who had minimal comorbidities. Future studies should clarify whether early disease events (e.g., profound CD4 decline) may trigger chronic CNS changes, and whether early CART prevents or reverses these changes.

Associations between retinal nerve fiber layer abnormalities and optic nerve examination

OBJECTIVE

Retinal nerve fiber layer (RNFL) abnormalities detected by optical coherence tomography (OCT) are useful markers for axonal loss and visual dysfunction in multiple sclerosis (MS), but their role in routine clinical management is not well-studied.

METHODS

Clinical and OCT examinations were performed on 240 patients attending a neurology clinic. Using OCT 5th percentile to define abnormal RNFL thickness, we compared eyes classified by neurologists as having optic atrophy to RNFL thickness, and afferent pupillary defect (APD) to RNFL thickness ratios of eye pairs.

RESULTS

Mean RNFL thickness was less in eyes classified by neurologists as having optic atrophy (79.4 ± 21 μm; n=63) vs those without (97.0 ± 15 μm; n=417; p < 0.001, t test) and in eyes with an APD (84.1 ± 16 μm; n=44) than without an APD (95.8 ± 17 μm; n=436; p < 0.001). Physicians' diagnostic accuracy for detecting pallor in eyes with an abnormal RNFL thickness was 79% (sensitivity=0.56; specificity=0.82). Accuracy for detecting a RAPD in patients with mean RNFL ratio (affected eye to unaffected eye) <0.90 was 73% (sensitivity=0.30; specificity=0.86). Ability to detect visual pathway injury via assessment of atrophy and APD differed between neurologists.

CONCLUSIONS

OCT reveals RNFL abnormality in many patients in whom eyes are not classified by neurologic examiners as having optic atrophy. Further study is needed to define the role of OCT measures in the context of examinations for optic atrophy and APD by neuroophthalmologists. OCT-measured RNFL thickness is likely to have an important future role in the clinical setting.

Hepatitis C seropositivity is not a risk factor for sensory neuropathy among patients with HIV

BACKGROUND

Sensory neuropathy (SN) is common in patients with HIV. Hepatitis C (HCV) coinfection is often cited as an HIV-SN risk factor, but data to support this are lacking. This collaboration aimed to examine the association between HCV serostatus and SN risk among ambulatory HIV-positive patients.

METHODS

Patients with HIV were assessed in cross-sectional studies in Baltimore, Jakarta, Johannesburg, Kuala Lumpur, Melbourne, and Sydney for SN (defined by both supportive symptoms and signs). HCV seropositivity was assessed as an SN risk using a chi(2) test, followed by logistic regression modeling to correct for treatment exposures and demographics.

RESULTS

A total of 837 patients of African, Asian, and Caucasian descent were studied. HCV seroprevalence varied by site (Baltimore n = 104, 61% HCV+; Jakarta 96, 51%; Johannesburg 300, 1%; Kuala Lumpur 97, 10%; Melbourne 206, 16%; Sydney 34, 18%). HCV seropositivity was not associated with increased SN risk at any site, but was associated with reduced SN risk in Melbourne (p = 0.003). On multivariate analyses, the independent associations with SN were increasing age, height, and stavudine exposure. HCV seropositivity was not independently associated with an increased SN risk at any site, but associated independently with reduced SN risk in Baltimore (p = 0.04) and Melbourne (p = 0.06).

CONCLUSIONS

Hepatitis C (HCV) seropositivity was not associated with increased sensory neuropathy risk among HIV-positive patients at any site. While we were unable to assess HCV RNA or liver damage, the data suggest that HCV coinfection is not a major contributor to HIV-SN. HCV = hepatitis C; SN = sensory neuropathy.

Acetyl-l-carnitine and nucleoside reverse transcriptase inhibitor-associated neuropathy in HIV infection

OBJECTIVES

Antiretroviral toxic neuropathy (ATN) is associated with dideoxynucleoside reverse transcriptase inhibitor use in patients infected with HIV, possibly as a result of mitochondrial toxicity. Acetyl-l-carnitine (ALC) has been linked to symptomatic improvement in ATN. We present an open-label single-arm pilot study to evaluate changes in intra-epidermal nerve fibre (IENF) density and mitochondrial DNA (mtDNA) copies/cell among subjects treated with 3000 mg ALC daily.

METHODS

Punch skin biopsies were examined at baseline and after 24 weeks of therapy. Participants reported neuropathic symptoms using the Gracely Pain Intensity Score. Neurological examinations were completed.

RESULTS

Twenty-one subjects completed the study. ALC was generally well tolerated. The IENF density did not change in cases completing 24 weeks of ALC therapy, with median (90% confidence interval) IENF changes of -1.70 (-3.50, infinity) (P=0.98) and 2.15 (-0.10, infinity) (P=0.11) for the distal leg and proximal thigh, respectively. Fat mtDNA copies/cell did not change with therapy. Improvements in neuropathic pain (P<0.01), paresthesias (P=0.01), and symptoms of numbness (P<0.01) were noted. Similarly, improvement was noted on the Gracely Pain Intensity Score.

CONCLUSIONS

ALC therapy coincided with improvements in subjective measures of pain in this open-label single-arm study. However, changes were not observed in objective measures of IENF density or mtDNA levels, providing little objective support for use of ALC in this setting.

Biomarkers of HIV-1 CNS infection and injury

While it is clear that HIV-1 can cause CNS dysfunction, current approaches to classification and diagnosis of this dysfunction rely on syndromic definitions or measures of abnormality on neuropsychological testing in the background context of HIV-1 infection. These definitions have been variably applied, offer only limited sensitivity or specificity, and do not easily distinguish active from static brain injury. Supplanting or augmenting these approaches with objective biologic measurements related to underlying disease processes would provide a major advance in classification, diagnosis, epidemiology, and treatment assessment. Two major avenues are now actively pursued to this end: 1) analysis of soluble molecular markers in CSF and, to a lesser degree, in blood, and 2) neuroimaging markers using anatomic, metabolic, and functional measurements. This review considers the rationale and prospects of these approaches.

Prevalence of and risk factors for HIV-associated neuropathy in Melbourne, Australia 1993-2006

OBJECTIVES

The aim of the study was to describe the prevalence of and risk factors for HIV-associated sensory neuropathy (HIV-SN) in 2006 [the era of stavudine, didanosine and zalcitabine (dNRTI)-sparing highly active antiretroviral therapy (HAART)] and to compare our findings with data obtained in the same clinic in 1993 (pre-HAART) and 2001 (frequent use of dNRTI-containing HAART).

METHODS

This was a cross-sectional comparative study using convenience sampling. HIV-positive adults attending a tertiary referral clinic over a 2-week period were screened for HIV-SN using the AIDS Clinical Trials Group screening tool. HIV-SN was defined as present if the patient had both neuropathic symptoms and abnormal signs. Demographic, clinical, laboratory and treatment data were considered as possible risk factors for HIV-SN, and results were compared with data obtained in the same clinic in 1993 and 2001.

RESULTS

One hundred patients were screened. The prevalence of HIV-SN was 42%, which was unchanged since 2001 (44%) despite a significant reduction in the use of dNRTIs. HIV-SN remained much more common than in 1993 (42% vs 13%; P<0.0001). The only independent associations with HIV-SN in 2006 were increasing patient age and a history of exposure to either stavudine or indinavir. This compares with 1993 when neuropathy was increased in those with Mycobacterium avium complex infection, and 2001 when patient age and use of stavudine and didanosine were the independent associations with HIV-SN in this clinic.

CONCLUSIONS

HIV-SN remained common among ambulatory patients in 2006 (42% prevalence) despite a significant reduction in the use of dNRTIs. In addition to patient age and stavudine exposure, indinavir use may be a risk factor for HIV-SN.

Updated research nosology for HIV-associated neurocognitive disorders

In 1991, the AIDS Task Force of the American Academy of Neurology published nomenclature and research case definitions to guide the diagnosis of neurologic manifestations of HIV-1 infection. Now, 16 years later, the National Institute of Mental Health and the National Institute of Neurological Diseases and Stroke have charged a working group to critically review the adequacy and utility of these definitional criteria and to identify aspects that require updating. This report represents a majority view, and unanimity was not reached on all points. It reviews our collective experience with HIV-associated neurocognitive disorders (HAND), particularly since the advent of highly active antiretroviral treatment, and their definitional criteria; discusses the impact of comorbidities; and suggests inclusion of the term asymptomatic neurocognitive impairment to categorize individuals with subclinical impairment. An algorithm is proposed to assist in standardized diagnostic classification of HAND.

Correlates of epidermal nerve fiber densities in HIV-associated distal sensory polyneuropathy

OBJECTIVE

To demonstrate the relationship between epidermal nerve fiber density (ENFD) in the leg and the phenotype of HIV-associated distal sensory polyneuropathy (HIV-DSP) in a multicenter prospective study (ACTG A5117).

METHODS

A total of 101 HIV-infected adults, with CD4 cell count <300 cells/mm(3) and who had received antiretroviral therapy (ART) for at least 15 consecutive weeks, underwent standardized clinical and electrophysiologic assessment. All 101 subjects were biopsied at the distal leg (DL) and 99 at the proximal thigh (PT) at baseline. ENFD was assessed by skin biopsy using PGP9.5 immunostaining. Associations of ENFD with demographics, ART treatment, Total Neuropathy Score (TNS), sural sensory nerve action potential (SNAP) amplitude and conduction velocity, quantitative sensory testing (QST) measures, and neuropathic pain were explored.

RESULTS

ENFD at the DL site correlated with neuropathy severity as gauged by TNS (p < 0.01), the level of neuropathic pain quantified by the Gracely Pain Scale (GPS) (p = 0.01) and Visual Analogue Scale (VAS) (p = 0.01), sural SNAP amplitude (p < 0.01), and toe cooling (p < 0.01) and vibration (p = 0.02) detection thresholds. ENFD did not correlate with neurotoxic ART exposure, CD4 cell count, or plasma HIV-1 viral load.

CONCLUSIONS

In subjects with advanced HIV-1 infection, epidermal nerve fiber density (ENFD) assessment correlates with the clinical and electrophysiologic severity of distal sensory polyneuropathy (DSP). ENFD did not correlate with previously established risk factors for HIV-DSP, including CD4 cell count, plasma HIV-1 viral load, and neurotoxic antiretroviral therapy exposure.

Associative and predictive biomarkers of dementia in HIV-1-infected patients

BACKGROUND

Infection with HIV can result in a debilitating CNS disorder known as HIV dementia (HIV-D). Since the advent of highly active antiretroviral therapy (HAART), the incidence of HIV-D has declined, but the prevalence continues to increase. In this new era of HIV-D, traditional biomarkers such as CSF viral load and monocyte chemotactic protein 1 levels are less likely to be associated with dementia in patients on HAART and biomarkers that can predict HIV-D have not yet been identified.

OBJECTIVE

To identify biomarkers that are associated with and can predict HIV-D.

METHODS

We grouped patients with HIV based on changes in cognitive status over a 1-year period and analyzed sphingolipid, sterol, triglyceride, antioxidant, and lipid peroxidation levels in CSF.

RESULTS

We found that increased levels of the vitamin E and triglyceride C52 predicted the onset or worsening of dementia. Elevated levels of sphingomyelin were associated with inactive dementia. Elevated levels of ceramide and the accumulation of 4-hydroxynonenals were associated with active dementia.

CONCLUSIONS

We interpret these findings to indicate that early in the pathogenesis of HIV dementia, there is an up-regulation of endogenous antioxidant defenses in brain. The failure of this attempted neuroprotective mechanism leads to the accumulation of sphingomyelin and moderate cognitive dysfunction. The breakdown of this enlarged pool of sphingomyelin to ceramide and the accumulation of highly reactive aldehydes are associated with declining cognitive function. Thus, elevations in endogenous protective mechanisms may identify patients who are at increased risk of the development of HIV dementia.

Impaired reinnervation in HIV infection following experimental denervation

OBJECTIVE

To determine whether abnormalities in peripheral nerve regeneration are present in HIV-infected individuals.

DESIGN

We studied human epidermal nerve fiber reinnervation by collateral and regenerative sprouting using validated cutaneous nerve injury models in healthy control subjects and those infected with HIV. Characteristics associated with the degree of reinnervation were identified.

METHODS

Seventy-one healthy volunteers and 22 HIV+ individuals underwent topical capsaicin treatment at the distal lateral thigh resulting in complete epidermal denervation. Regenerative sprouting was quantified in skin biopsies at intervals up to 100 days. Five healthy subjects and 5 HIV+ individuals underwent a 3-mm distal thigh punch skin biopsy to create an intracutaneous axotomy, followed 2 months later by a 4-mm overlapping biopsy. The collateral sprouting distance was measured.

RESULTS

The mean rate of regenerative sprouting was highest for healthy control subjects (0.17 +/- 0.073 fibers/mm/day), followed by HIV+ subjects without neuropathy (0.13 +/- 0.06) and then HIV+ subjects with neuropathy (0.097 +/- 0.07) (p = 0.002). Regenerative sprouting was significantly associated with the baseline intraepidermal nerve fiber density (p < 0.001) but not with HIV viral load, HIV duration, CD4 cell count, or ApoE epsilon4 status. HIV+ individuals were also found to have a reduced collateral sprouting rate compared to controls (5.31 mum +/- 0.73 vs 9.78 mum +/- 1.5/day, p = 0.03).

CONCLUSIONS

Abnormalities in both regenerative and collateral sprouting are present in people infected with HIV, and are detectable in subjects with and without evidence of peripheral nerve dysfunction. Our results indicate that abnormalities in nerve regeneration occur early in HIV infection and provide a rationale to include neuropathy-free HIV subjects in regenerative peripheral nerve trials.

Neuropsychological abnormalities in patients with dementia in CRF 01_AE HIV-1 infection

HIV-associated dementia (HAD) is not firmly established in patients with circulating recombinant form (CRF) 01_AE HIV-1. In this study, we compared neuropsychological performance among 15 Thai individuals with HAD, 15 Thai individuals without HAD, and 30 HIV-negative control subjects. HIV-1 participants were highly active anti-retroviral therapy naive and matched by age, education, and CD4 count. Neuropsychological testing abnormalities were identified in most cognitive domains among HAD vs HIV-negative participants, confirming the presence of HAD in CRF01_AE.

Frequency of and risk factors for HIV dementia in an HIV clinic in sub-Saharan Africa

OBJECTIVE

To measure the frequency and associated risk factors of HIV dementia in an HIV clinic in Kampala, Uganda.

METHODS

We systematically sampled 78 HIV-seropositive (HIV+) patients from an ambulatory HIV clinic. Participants underwent detailed sociodemographic, medical history, functional, neurologic, and neuropsychological evaluations. One hundred HIV-negative patients were recruited to provide normative data for the neuropsychological tests. A logistic regression model was constructed to determine risk factors associated with the diagnosis of HIV dementia.

RESULTS

Thirty-one percent (24 of 78) of the HIV+ patients had HIV dementia. Advanced age and low CD4(+) T-lymphocyte count (CD4 count) were the only variables identified as significant risk factors in the logistic regression model. Each additional 10 years of age conferred a greater than twofold risk of HIV dementia (OR 2.06, 95% CI: 1.05 to 4.07; p < 0.05). Reduced levels of CD4 count (100 cells/muL decrement) was associated with a 60% increase in the odds of having HIV dementia (OR 1.6, 95% CI: 1.04 to 2.33; p < 0.05).

CONCLUSION

HIV dementia is common in HIV-seropositive Ugandan individuals attending an AIDS clinic. It is more frequently associated with patients of advanced age and decreased CD4 count.

Immune reconstitution inflammatory syndrome in the CNS of HIV-infected patients

OBJECTIVE

To describe challenges in diagnosis and management of patients with clinical syndromes of immune reconstitution inflammatory syndrome (IRIS) involving the CNS.

METHODS

The authors describe three patients with clinically distinct neurologic manifestations of IRIS with HIV infection who presented as diagnostic and therapeutic challenges.

RESULTS

One patient with cryptococcal meningitis developed acute cerebellitis with mass effect and brainstem compression. Corticosteroid therapy was associated with complete resolution of the cerebellar lesion but the patient developed VZV encephalitis. Another patient with progressive multifocal leukoencephalopathy developed subacute progression of focal neurologic deficits associated with contrast enhancing lesions on brain MRI. This patient had spontaneous resolution of the lesion but was left with residual deficits. One patient developed a progressive dementing syndrome and deterioration over several months resulting in coma during combination antiretroviral therapy. A brain biopsy in this latter patient showed massive infiltration of T lymphocytes predominantly of the CD8 subtype. This patient had a significant improvement with corticosteroids and change in antiretroviral regimen although she was left with residual cognitive impairment.

CONCLUSIONS

Immune reconstitution inflammatory syndrome should be suspected in patients who show clinical or radiologic deterioration following initiation of antiretroviral therapy accompanied with improvement in CD4 cell count and viral load. Some patients may respond to a brief course of treatment with corticosteroids.

HIV neuropathy natural history cohort study: assessment measures and risk factors

BACKGROUND

Distal sensory polyneuropathy (DSP) is the most common neurologic complication of human immunodeficiency virus (HIV) infection. Risk factors for DSP have not been adequately defined in the era of highly active antiretroviral therapy.

METHODS

The authors evaluated 101 subjects with advanced HIV infection over 48 weeks. Assessments included a brief peripheral neuropathy (PN) screen (BPNS), neurologic examination, nerve conduction studies, quantitative sensory testing (QST), and skin biopsies with quantitation of epidermal nerve fiber density. Data were summed into a Total Neuropathy Score (TNS). The presence, severity, and progression of DSP were related to clinical and laboratory results.

RESULTS

The mean TNS (range 0 to 36) was 8.9, with 38% of subjects classified as PN-free, 10% classified as having asymptomatic DSP, and 52% classified as having symptomatic DSP. Progression in TNS from baseline to week 48 occurred only in the PN-free group at baseline (mean TNS change = 1.16 +/- 2.76, p = 0.03). Factors associated with progression in TNS were lower current TNS, distal epidermal denervation, and white race. As compared with the TNS diagnosis of PN at baseline, the BPNS had a sensitivity of 34.9% and a specificity of 89.5%.

CONCLUSIONS

In this cohort of advanced human immunodeficiency virus (HIV)-infected subjects, distal sensory polyneuropathy was common and relatively stable over 48 weeks. Previously established risk factors, including CD4 cell count, plasma HIV RNA, and use of dideoxynucleoside antiretrovirals were not predictive of the progression of distal sensory polyneuropathy (DSP). Distal epidermal denervation was associated with worsening of DSP. As compared with the Total Neuropathy Score, the brief peripheral neuropathy screen had relatively low sensitivity and high specificity for the diagnosis of DSP.

Antiretroviral use and other risks for HIV-associated neuropathies in an international cohort

OBJECTIVE

To explore the association between specific nucleoside reverse transcriptase inhibitors and sensory neuropathies (SNs) and define the modifying roles of hepatitis C (HCV), vitamin B12 deficiency, and impaired glucose tolerance.

METHODS

The authors conducted a prospective cohort study of 147 HIV-infected adults at two sites chosen to emphasize demographic differences. Standardized assessments included detailed antiretroviral histories, neurologic examinations, skin biopsies for epidermal nerve quantitation, and quantitative sensory testing.

RESULTS

There were significant differences between subjects at Johns Hopkins University (JHU) and Monash University (MU) in gender, race, HIV transmission route, and HCV seroprevalence. Symptomatic SN was present in 49% at JHU and 55% at MU (chi2 = 4.02, p = 0.134) and was significantly more common in those at least age 40 than younger patients (odds ratio [OR] = 2.87, 95% CI = 1.27, 6.49). After adjusting for site, age, and CD4 cell count, exposure to didanosine (ddI) or stavudine (d4T) was associated with an significantly increased likelihood of symptomatic SN (ddI: OR = 3.21, 95% CI: 1.56, 6.60; d4T: OR = 7.66, 95% CI: 2.89, 20.33). Plasma HIV RNA, lactate, and HCV were not associated with SN. Quantitative vibratory testing identified neuropathy with a positive predictive value of 76% and epidermal nerve fiber densities 59%.

CONCLUSIONS

Exposure to stavudine and didanosine was significantly associated with a heightened risk for symptomatic sensory neuropathy. Reduced vibration thresholds and epidermal nerve fiber densities had the highest diagnostic efficiency of the laboratory indicators of neuropathy examined, but were relatively insensitive in isolation.

The utility of skin biopsy for prediction of progression in suspected small fiber neuropathy

Twenty-eight patients with sensory complaints of unknown etiology had repeated skin biopsies. Patients with large nerve fiber swellings on initial biopsy showed a decline in epidermal nerve fiber density on repeated biopsies (p < 0.05 within group; p < 0.05 vs those without swellings). Patients without nerve fiber swellings did not have changes in nerve fiber density between biopsies. Patients with large nerve fiber swellings were most likely to present clinically with paresthesias (p < 0.05).

Markers of immune activation and viral load in HIV-associated sensory neuropathy

BACKGROUND

HIV infection is associated with a painful distal sensory polyneuropathy (DSP) that can severely limit the quality of life of affected subjects. The pathogenesis of DSP is unknown, although both HIV proteins and products of immune activation triggered by HIV infection have been implicated.

OBJECTIVE

To assess the association between baseline markers of immune activation and HIV RNA levels (viral load) and time to symptomatic DSP (SDSP).

METHODS

A cohort of 376 subjects, most receiving highly active antiretroviral therapy (HAART), were followed semiannually for up to 48 months. Blood and CSF levels of HIV viral load, monocyte chemotactic protein-1, macrophage colony-stimulating factor (M-CSF), matrix metalloproteinase-2, and tumor necrosis factor-alpha were measured in addition to CD4 lymphocyte cell count.

RESULTS

In subjects without SDSP at baseline (62.5% of the cohort), among the virologic and immunologic markers, only baseline CSF M-CSF levels were associated with time to SDSP (hazard ratio = 2.97, p = 0.05). The Kaplan-Meier estimate of the 1-year incidence of SDSP was 21%, a 15% decrease from that observed in the Dana cohort, a pre-HAART cohort enrolled with the same inclusion/exclusion criteria.

CONCLUSION

Highly active retroviral therapy (HAART) has changed the natural history of HIV-associated symptomatic distal sensory polyneuropathy (SDSP), which may explain, in contrast with studies from the pre-HAART era, the lack of association between SDSP and baseline HIV viral load and CD4 cell count.

Factors influencing nerve regeneration in a trial of timcodar dimesylate

The authors assessed the ability of the neurophilin compound, timcodar dimesylate, to accelerate the return of epidermal nerve fiber density (ENFD) after a standardized nerve injury in a randomized double blind, placebo controlled trial. While there was no difference in the regeneration rate between the treatment and placebo arms, the baseline ENFD (p = 0.006), height (p = 0.02), and race (p = 0.03) were associated with the regeneration rate.

EFNS guidelines on the use of skin biopsy in the diagnosis of peripheral neuropathy

Skin biopsy has become a widely used tool to investigate small calibre sensory nerves including somatic unmyelinated intraepidermal nerve fibres (IENF), dermal myelinated nerve fibres, and autonomic nerve fibres in peripheral neuropathies and other conditions. Different techniques for tissue processing and nerve fibre evaluation have been used. In March 2004, a Task Force was set up under the auspices of the European Federation of Neurological Societies (EFNS) with the aim of developing guidelines on the use of skin biopsy in the diagnosis of peripheral neuropathies. We searched the Medline database from 1989, the year of the first publication describing the innervation of human skin using immunostaining with anti-protein-gene-product 9.5 (PGP 9.5) antibodies, to 31 March 2005. All pertinent papers were rated according to the EFNS guidance. The final version of the guidelines was elaborated after consensus amongst members of the Task Force was reached. For diagnostic purposes in peripheral neuropathies, we recommend performing a 3-mm punch skin biopsy at the distal leg and quantifying the linear density of IENF in at least three 50-mum thick sections per biopsy, fixed in 2% PLP or Zamboni's solution, by bright-field immunohistochemistry or immunofluorescence with anti-PGP 9.5 antibodies (level A recommendation). Quantification of IENF density closely correlated with warm and heat-pain threshold, and appeared more sensitive than sensory nerve conduction study and sural nerve biopsy in diagnosing small-fibre sensory neuropathy. Diagnostic efficiency and predictive values of this technique were very high (level A recommendation). Confocal microscopy may be particularly useful to investigate myelinated nerve fibres, dermal receptors and dermal annex innervation. In future, the diagnostic yield of dermal myelinated nerve fibre quantification and of sweat gland innervation should be addressed. Longitudinal studies of IENF density and regeneration rate are warranted to correlate neuropathological changes with progression of neuropathy and to assess the potential usefulness of skin biopsy as an outcome measure in peripheral neuropathy trials (level B recommendation). In conclusion, punch skin biopsy is a safe and reliable technique (level A recommendation). Training in an established cutaneous nerve laboratory is recommended before using skin biopsy as a diagnostic tool in peripheral neuropathies. Quality control at all levels is mandatory.

Evaluation of HIV RNA and markers of immune activation as predictors of HIV-associated dementia

OBJECTIVE

To evaluate whether baseline levels of plasma and CSF HIV RNA, tumor necrosis factor alpha (TNFalpha), monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinase-2 (MMP-2), or macrophage colony stimulating factor (M-CSF) are predictors of incident HIV-associated dementia (HIVD) in a cohort with advanced HIV infection.

METHODS

A total of 203 nondemented subjects with CD4 lymphocyte counts less than 200/muL, or <300/microL but with cognitive impairment, underwent semiannual neurologic, cognitive, functional, and laboratory assessments. HIVD and minor cognitive motor disorder (MCMD) were defined using American Academy of Neurology criteria. The cumulative incidence of HIVD was estimated using Kaplan-Meier curves. Cox proportional hazards regression models were used to examine the associations between biologic variables and time to HIVD, adjusting for age, sex, years of education, duration of HIV infection, type of antiretroviral use, premorbid IQ score, and presence of MCMD.

RESULTS

After a median follow-up time of 20.7 months, 74 (36%) subjects reached the HIVD endpoint. The dementia was mild in 70% of cases. The cumulative incidence of HIVD was 20% at 1 year and 33% at 2 years. Highly active antiretroviral therapy (HAART) was used by 73% of subjects at baseline. A plasma HIV RNA level was undetectable in 23% of subjects and a CSF HIV RNA level was undetectable in 48% of subjects. In adjusted analyses, neither plasma nor CSF HIV RNA levels (log10) were associated with time to HIVD; log10 levels of plasma TNFalpha (HR 3.07, p = 0.03) and CSF MCP-1 (HR = 3.36, p = 0.06) tended to be associated with time to HIVD.

CONCLUSION

The lack of association between baseline plasma and CSF HIV RNA levels and incident dementia suggests highly active antiretroviral therapy may be affecting CNS viral dynamics, leading to lower HIV RNA levels, and therefore weakening the utility of baseline HIV RNA levels as predictors of HIV-associated dementia.

Dysregulation of sphingolipid and sterol metabolism by ApoE4 in HIV dementia

BACKGROUND

Polymorphisms in apolipoprotein E have been associated with worse prognoses in numerous neurodegenerative conditions, including HIV dementia (HIVD). Despite these correlative observations, there has been little evidence suggesting a mechanism whereby the expression of ApoE4 renders neurons susceptible to insult.

METHODS

Electrospray ionization tandem mass spectrometry was used to quantify levels of sphingolipids and sterols in brains of HIVD patients. Data were stratified according to APOE genotype.

RESULTS

The authors found evidence of dysregulated lipid and sterol metabolism in HIVD patients with an APOE4 genotype. They also found elevations of sphingomyelin, ceramide, and cholesterol in the medial frontal cortex, parietal cortex, and cerebellum of HIVD patients with an APOE3/4 or APOE4/4 genotype compared with HIVD patients with an APOE3/3 genotype. There was no difference in the number of astrocytes or activated microglia in any brain region of the two patient populations, suggesting that modification of lipid metabolism in HIVD patients with an APOE4 genotype was not the result of increased CNS inflammation.

CONCLUSIONS

HIV dementia patients with an APOE4 genotype may be sensitized to neural insults because of dysregulations in lipid metabolism.

CSF soluble Fas correlates with the severity of HIV-associated dementia

Soluble Fas (sFas) and soluble Fas ligand (sFasL) are associated with cellular dysfunction and death and are elevated in CSF from patients with HIV dementia (HIV-D). The authors investigated whether these markers correlated with dementia severity and course. sFas and sFasL were measured in 15 highly active antiretroviral therapy (HAART)-naïve HIV-D subjects, 30 HAART-naïve HIV+ controls, and 17 HIV-controls. HIV-D subjects had higher CSF sFas levels than controls. Subjects with moderate/severe dementia had higher CSF sFas levels than those with mild dementia. CSF sFas trended lower in those with progressive dementia.

Response to systemic HIV viral load suppression correlates with psychomotor speed performance

The authors evaluated the association of a virologic response to highly active antiretroviral therapy, or a subsequent rebound, with performance on two measures of psychomotor speed in HIV-positive subjects. Virologic suppression was associated with improved performance on measures of psychomotor speed, and virologic rebound was associated with psychomotor speed performance decline. Changes in plasma HIV viral load in HIV-positive individuals with cognitive slowing correlate with performance on tests of psychomotor speed.

Inter-rater reliability of a clinical staging of HIV-associated cognitive impairment

OBJECTIVE

To determine the inter-rater reliability of a modification of the Memorial Sloan-Kettering (MSK) Staging for HIV-associated cognitive impairment.

METHODS

Data were abstracted on neurologic, neuropsychological, and functional status on 100 individuals participating at four sites in the Northeast AIDS Dementia (NEAD) Consortium cohort study, a longitudinal study of predictors of cognitive impairment in HIV-infected individuals. Neuropsychological performance was defined 1) based on the neuropsychologist's global impression and 2) solely based on neuropsychological test scores. Raters at each site used the abstracted data to assign an MSK stage to each subject blind to any identifying information. Inter-rater reliability was assessed using kappa statistics. Agreement between computer-generated ratings and site-generated ratings was also assessed.

RESULTS

Kappa statistics for pair-wise agreement among the sites regarding MSK stage ranged from 0.70-0.91, representing good to excellent agreement between sites. Agreement between computer-generated ratings and site-generated ratings was in the good to excellent range (0.62-0.79).

CONCLUSIONS

The authors have modified the MSK rating scale and developed a reliable instrument that can be used in multicenter studies. This instrument will be useful in staging HIV-dementia in future longitudinal studies and will be valuable in increasing accuracy of clinicopathologic studies.

Lamotrigine for HIV-associated painful sensory neuropathies: a placebo-controlled trial

OBJECTIVE

To evaluate the efficacy and tolerability of lamotrigine (LTG) for the treatment of pain in HIV-associated sensory neuropathies.

METHODS

In a randomized, double-blind study, patients with HIV-associated distal sensory polyneuropathy (DSP) received LTG or placebo during a 7-week dose escalation phase followed by a 4-week maintenance phase. Randomization was stratified according to whether or not patients were currently using neurotoxic antiretroviral therapy (ART).

RESULTS

The number of patients randomized was 92 (62 LTG, 30 placebo) in the stratum receiving neurotoxic ART and 135 (88 LTG, 47 placebo) in the stratum not receiving neurotoxic ART. Mean change from baseline in Gracely Pain Scale score for average pain was not different between LTG and placebo at the end of the maintenance phase in either stratum, but the slope of the change in Gracely Pain Scale score for average pain reflected greater improvement with LTG than with placebo in the stratum receiving neurotoxic ART (p = 0.004), as did the mean change from baseline scores on the Visual Analogue Scale for Pain Intensity and the McGill Pain Assessment Scale and patient and clinician ratings of global impression of change in pain (p </= 0.02). The incidence of adverse events, including rash, was similar between LTG and placebo.

CONCLUSIONS

Lamotrigine was well-tolerated and effective for HIV-associated neuropathic pain in patients receiving neurotoxic antiretroviral therapy. Additional research is warranted to understand the differing response among patients receiving neurotoxic antiretroviral therapy compared with those not receiving neurotoxic antiretroviral therapy.

A randomized clinical trial of CPI-1189 for HIV-associated cognitive-motor impairment

BACKGROUND

CPI-1189 is a compound with antioxidant properties that blocks tumor necrosis factor-alpha (TNFalpha) effects in animal models. It has neuroprotective properties in model systems for HIV-associated neurotoxicity and thus is a candidate for neuroprotective therapy in humans with HIV-associated CNS disease.

OBJECTIVE

To assess the tolerability and safety of CPI-1189 in treating HIV-associated cognitive-motor impairment.

METHODS

Sixty-four subjects with mild to moderate HIV-associated cognitive-motor impairment were randomized to receive either placebo or 50 or 100 mg daily of CPI-1189 in addition to optimal HIV therapy. Subjects were followed prospectively in a double-masked study for 10 weeks. The primary assessment was tolerability and safety of the compound. Secondary objectives examined neuropsychological and functional change associated with this treatment.

RESULTS

The study compound was well tolerated, with 91% of CPI-1189-treated subjects and 76% of placebo-treated subjects completing the trial. Skin rash was seen equally in placebo and active arms, but the only study withdrawals due to skin rash occurred in CPI-1189-treated subjects (n = 2). One subject developed a cataract on drug (100 mg/day). CD4 lymphocyte counts and plasma HIV viral load remained stable in all groups throughout the trial. No significant treatment effects were observed on the change in composite Z-scores for eight neuropsychologic measures (NPZ-8). The Grooved Pegboard Test (nondominant) showed improved performance with CPI-1189 at 100 mg/day (p = 0.01), but no other neuropsychometric or functional measures demonstrated significant improvement.

CONCLUSIONS

CPI-1189 was well tolerated in HIV subjects with cognitive-motor disorder. This study was not powered to conclusively determine efficacy and showed no consistent treatment-associated improvement in cognitive or functional measures.

Incidence of and risk factors for HIV-associated distal sensory polyneuropathy

OBJECTIVE

To assess the incidence of and risk factors for distal sensory polyneuropathy (DSP) in a cohort of HIV-infected subjects.

METHODS

We followed 272 subjects semiannually for up to 30 months. DSP was diagnosed if subjects had decreased or absent ankle jerks, decreased or absent vibratory perception at the toes, or decreased pinprick or temperature in a stocking distribution. Subjects were further classified at each visit as having asymptomatic DSP (ADSP) (signs only) or symptomatic DSP (SDSP) if, in addition to the neurologic signs, paresthesias or pain was reported.

RESULTS

At baseline, 45% of the subjects did not meet criteria for DSP, 20% met criteria for ADSP, and 35% met criteria for SDSP. Dideoxynucleoside therapy was used by 23% of the patients, and this treatment was independent of their neuropathy status. In longitudinal univariate analyses, history of AIDS diagnoses (hazard ratio [HR] = 1.89; p = 0.02) and lower CD4 cell count (HR = 0.69; p = 0.0006) were risk factors for incident DSP (ADSP or SDSP). However, for incident SDSP only, in addition to history of AIDS diagnoses, mood and neurologic (other than DSP) and functional abnormalities were significant risk factors. Functional abnormalities remained a significant risk factor in a multiple regression analysis. The presence of ADSP and the use of dideoxynucleosides at baseline were not significant risk factors for incident SDSP. The Kaplan-Meier estimate of the 1-year incidence of SDSP was 36%.

CONCLUSION

Subjects with moderate-to-severe immunosuppression from HIV infection commonly have SDSP. However, sex, use of dideoxynucleosides, and presence of ADSP were not significant risk factors for SDSP.

Reduced intraepidermal nerve fiber density in HIV-associated sensory neuropathy

OBJECTIVE

To explore the relationship between intraepidermal nerve fiber (IENF) density in HIV-associated sensory neuropathy (HIV-SN) to measurements of neuropathy severity and progression of HIV disease.

BACKGROUND

SN affects 30% of individuals with AIDS, and treatment is often ineffective. Recombinant human nerve growth factor (rhNGF) has been proposed as a trophic factor for unmyelinated nerve fibers injured in HIV-SN, and a clinical trial has recently concluded. Skin biopsy with IENF density determination has emerged as a diagnostic test for patients with small-fiber sensory neuropathy.

METHODS

Sixty-two of the 270 patients with HIV-SN who participated in the trial of rhNGF were included in a substudy examining epidermal nerve fibers. IENF density was compared with neuropathic pain intensity (measured with the Gracely Pain Scale), patient and physician global pain assessments, quantitative sensory testing, CD4 counts, and plasma HIV RNA levels both at baseline and at conclusion of the placebo-controlled phase.

RESULTS

IENF density was inversely correlated with neuropathic pain as measured by patient (p = 0.004) and physician (p = 0.05) global pain assessments, but not using the Gracely Pain Scale. Decreased IENF density at the distal leg was associated with lower CD4 counts and higher plasma HIV RNA levels. IENF density measurements were stable over time.

CONCLUSIONS

IENF loss at the distal leg is associated with increased neuropathic pain, lower CD4 counts, and higher plasma viral load in HIV-SN. The robustness of the longitudinal measurement of IENF density supports its use in future longitudinal studies and clinical trials.

HIV in the brain: RNA levels and patterns of zidovudine resistance

OBJECTIVE

To examine the association between HIV RNA levels, patterns of antiretroviral resistance, and neurologic status.

METHODS

Autopsy samples from 13 HIV-infected subjects were examined for HIV-1 viral RNA (vRNA), and viral reverse transcriptase (RT) genotype was determined. All subjects had been clinically characterized using standard instruments before death.

RESULTS

The median HIV-1 vRNA level in brain samples from subjects with moderate dementia was 7.79 log(10) copies/g (range 5.56 to 9.75 log(10) copies/g) compared with 5.44 log(10) copies/g (range 3.51 to 9.32 log(10) copies/g) for mildly demented subjects and 4.87 log(10) copies/g (3.51 to 6.86 log(10) copies/g) for those obtained from nondemented individuals. There were differences between subjects with moderate dementia and nondemented subjects (p = 0.0002) and between subjects with moderate and mild dementia (p = 0.0128). No significant differences among the groups were observed for vRNA levels in peripheral tissues. Some demented subjects had relatively low levels of HIV-1 vRNA, and paradoxically some nondemented subjects had high vRNA brain levels. Little subject effect in vRNA was noted in peripheral regions, but high regional variation in vRNA was noted within the brain. Patterns of the major zidovudine (ZDV) RT mutations in brain and peripheral tissues were concordant in most subjects. Subjects with longer duration of exposure to ZDV tended to have lower brain vRNA levels and a greater number of RT mutations than those with limited to no exposure.

CONCLUSIONS

The presence and severity of HIV dementia correlates with the levels of productive HIV replication within the brain. Other pathophysiologic events (including macrophage activation) probably also contribute to neurologic dysfunction.

Long-term treatment with recombinant nerve growth factor for HIV-associated sensory neuropathy

HIV-associated distal sensory polyneuropathy (DSP) is a common complication of AIDS. No effective treatment is available. The authors investigated the long-term effect (48 weeks) of the neurotrophin nerve growth factor (NGF) in an open-label study of 200 subjects with HIV-associated DSP. Similar to their previously reported double-blind study, the authors showed that NGF was safe and well tolerated and significantly improved pain symptoms. However, there was no improvement of neuropathy severity as assessed by neurologic examination, quantitative sensory testing, and epidermal nerve fiber density.

Assessment of cutaneous innervation by skin biopsies

Skin biopsies that are immunostained to identify nerve fibers provide a new tool for assessing the small caliber nociceptors that terminate in the epidermis, as well as other cutaneous nerve fibers. Skin biopsies can be performed in multiple sites and can be repeated over time, so that a spatiotemporal profile of epidermal innervation can be constructed. This approach may help assess the progression of fiber loss in disease and of regeneration and re-innervation with treatment.

CSF antiretroviral drug penetrance and the treatment of HIV-associated psychomotor slowing

The authors evaluated whether highly active antiretroviral therapy (HAART) with multiple CSF-penetrating drugs results in greater improvement in HIV-associated psychomotor slowing than HAART with a single CSF-penetrating drug. Both groups had improvement in CD4 count, plasma viral load, as well as two tests of psychomotor speed. Comparing the two groups, there were no differences in the mean change for CD4 count, viral load, or any of the neuropsychological tests. Multiple and single CSF-penetrating HAART may be equivalent for treating HIV-associated psychomotor slowing.

The relative contributions of HAART and alpha-interferon for therapy of progressive multifocal leukoencephalopathy in AIDS

To explore the respective roles of highly active antiretroviral therapy (HAART) and alpha-interferon in improving survival of patients with AIDS-related PML, we retrospectively analyzed all patients with AIDS and PML who were referred to Johns Hopkins University HIV Neurology Program from 1985 to 2000. For 97 evaluable patients, we compared survival of those who were on HAART (three or more antiretroviral drugs) to those who were not on HAART. The effect of alpha-interferon was also studied. Multivariate analysis showed no difference in survival among patients on none, one, or two forms of antiretrovirals; however, survival was significantly greater for those on HAART. Whereas alpha-interferon use was shown to be associated with longer survival (P < 0.057), this effect was not independent of the effects of HAART. HAART significantly increases survival for patients with PML and AIDS; however, alpha-interferon does not appear to provide additional benefit.

Correlation between neurological progression and astrocyte apoptosis in HIV-associated dementia

The pathogenesis of HIV-associated dementia (HIVD) has been postulated to be due to the indirect effects of HIV infection, including the aberrant central nervous system production of cytokines and other neurotoxins. A correlation between the severity of dementia and production of neurotoxins in HIVD has been demonstrated. We have previously identified nonproductive HIV infection of astrocytes. Because astrocytes participate in the inactivation of neurotoxins, we hypothesize that HIV nonproductive infection of astrocytes may lead to an environment in which there is a significant level of astrocyte apoptosis and a consequent increase in the levels of neurotoxins and that this results in more rapidly progressing dementia. Postmortem brain tissue was examined from clinically well-characterized HIV-positive demented patients, HIV-positive nondemented patients, and HIV-seronegative nondemented control subjects. The HIVD group was further categorized into subjects with rapid and those with slow progression of dementia. Tissue was paraformaldehyde fixed and paraffin embedded, and 6-microm sections from the basal ganglia and mid-frontal gyrus were processed to detect apoptosis by in situ transferase dUTP nick end labeling. Astrocytes were co-localized using immunohistochemical techniques. In situ polymerase chain reaction (PCR) techniques were utilized to detect HIV DNA in astrocytes. The density of apoptotic astrocytes was significantly greater in the HIV-positive groups than in the HIV-negative group (p < 0.01). The HIVD rapid progressors had a significantly greater number of apoptotic astrocytes in the basal ganglia than did the HIVD slow progressors (p < 0.05). In addition, there were a greater number of HIV DNA-positive astrocytes, as demonstrated by in situ PCR, in the HIVD rapid progressors than in the slow progressor and HIV-nondemented groups. These data suggest that there is an increased rate of astrocyte loss in the subjects with rapidly progressive dementia, in association with an increased number of HIV DNA-positive astrocytes. The results emphasize the importance of understanding more completely the role of HIV infection of astrocytes in the neuropathogenesis of HIVD.

HIV-1 LTR C/EBP binding site sequence configurations preferentially encountered in brain lead to enhanced C/EBP factor binding and increased LTR-specific activity

Recent studies have shown that two CAAT/enhancer binding protein (C/EBP) sites are critically important for efficient human immunodeficiency virus (HIV) type 1 (HIV-1) replication within cells of the monocyte/macrophage lineage, a primary cell type infected by HIV-1 and a potentially important vehicle for transport of virus to the central nervous system (CNS). Given the relevance of HIV-1 LTR sequence variation with respect to HIV-1 replication within monocyte populations and the important role that monocyte tropism likely plays in HIV-1 infection of the brain, C/EBP site sequence variation was examined within peripheral blood- and brain-derived LTR populations. Brain-derived LTRs commonly possessed a C/EBP site I configuration (6G, comprised of a thymidine to guanosine substitution with respect to the clade B consensus sequence at position 6 of C/EBP site I) that leads to enhanced binding of C/EBP proteins over that observed with the HIV-1 clade B consensus sequence at this site. In contrast, the 6GC/EBP site I configuration appeared infrequently within sequenced peripheral blood-derived LTRs. In addition, C/EBP site II was even more highly conserved in brain-derived HIV-1 LTR populations than site I. This was not the case with peripheral blood-derived LTR C/EBP site II sequences. The high degree of C/EBP site II conservation in brain-derived LTRs was likely important in LTR regulation since the clade B consensus sequence conserved at C/EBP site II recruited high amounts of C/EBP family members. Transient transfection analyses indicated that conservation of the strong C/EBP site II in brain-derived LTRs was likely due to important interactions with Tat. Overall, brain-derived HIV-1 LTRs preferentially contained two highly reactive C/EBP binding sites, which may suggest that these sites play important roles in LTR-directed transcription during invasion and maintenance of HIV-1 in the central nervous system.

Identification by mRNA differential display of two up-regulated genes as candidate mediators of AIDS dementia

BACKGROUND

In the dementia associated with acquired immunodeficiency syndrome (AIDS), indirect pathomechanisms are important mediators of progressive neuronal injury and variable candidate molecules of potential pathogenetic importance have been identified.

MATERIALS AND METHODS

In an attempt to characterize additional mediators of human immunodeficiency virus type 1 (HIV-1)-induced neurotoxicity in vivo we have adapted the mRNA differential display technique to monitor the gene expression pattern in postmortem cortical tissue from AIDS patients with (n = 7) and without (n = 8) cognitive impairment as well as from HIV-1 seronegative controls (n = 4).

RESULTS

Out of 29 differentially expressed cDNAs, two cDNA clones had confirmed variation of transcriptional regulation as assessed by reverse Northern analysis and gene-specific reverse transcription polymerase chain reaction (RT-PCR) and were up-regulated in the cortex of patients with AIDS dementia. Nucleotide sequence analysis of the two cDNAs identified known genes not previously associated with the pathogenesis of AIDS dementia, including the neurotrophin receptor tyrosine kinase receptor B (TrkB) and the potassium channel human open rectifyer K+ channel (ORK) homologous open reading frame (HOHO1).

CONCLUSIONS

The altered expression of these transcripts may contribute to AIDS dementia through the enhancement of microglial activation and immunologic nitric oxide synthase (iNOS) activity by abnormal neurotrophic regulation and interference with membrane excitability through disturbance of local ion homeostasis.

HIV neuropathy: insights in the pathology of HIV peripheral nerve disease

HIV-associated neuropathies (HIV-N) have become the most frequent neurological disorder associated with HIV infection. The most common forms of HIV-N are the distal sensory polyneuropathy (DSP) and antiretroviral toxic neuropathies (ATN), disorders characterized mostly by sensory symptoms that include spontaneous or evoked pain that follow a subacute or chronic course. The main pathological features that characterize DSP and ATN include "dying back" axonal degeneration of long axons in distal regions, loss of unmyelinated fibers, and variable degree of macrophage infiltration in peripheral nerves and dorsal root ganglia. Marked activation of macrophages as well as the effect of pro-inflammatory cytokines appear to be the main immunopathogenic factors in DSP. Interference with DNA synthesis and mitochondrial abnormalities produced by nucleoside antiretrovirals have been hypothesized as pathogenic factors involved in ATN. The use of skin biopsy has become a useful tool in the evaluation of HIV-N. Reduction in fiber density, increased frequency of fiber varicosities and fiber fragmentation are prominent features of skin biopsies from patients with HIV-N. Other forms of HIV-N include acute or chronic inflammatory polyneuropathies, uncommon disorders that may ocur during seroconversion or early stages of HIV infection. Opportunisitic infections, mostly associated with cytomegalovirus or herpes zoster virus infection occur in late stages of AIDS and produce characteristic clinical features such as mononeuritis multiple or radiculopathies.

HIV-associated neurologic disease incidence changes:: Multicenter AIDS Cohort Study, 1990-1998

This study examined the temporal trends in the incidence rates of HIV dementia, cryptococcal meningitis, toxoplasmosis, progressive multifocal leukoencephalopathy, and CNS lymphoma from January 1990 to December 1998 in the Multicenter AIDS Cohort Study. The incidence rates for HIV dementia, cryptococcal meningitis, and lymphoma decreased following the introduction of highly active antiretroviral therapy (HAART). The proportion of new cases of HIV dementia with a CD4 count in a higher range (i.e., 201 to 350) since 1996 may be increasing.