Primary angiitis of the central nervous system and Alzheimer's disease: clinically and pathologically evident in a single patient

Two years after being successfully treated for biopsy confirmed primary angiitis of the central nervous system (PACNS), a 69-year-old woman presented with cognitive decline. In contrast to her first presentation, her altered mental function developed gradually, was not associated with headache or abnormal cerebrospinal fluid analysis, and did not improve with immunosuppression. Reevaluation of her original brain biopsy not only confirmed the presence of PACNS, but also revealed neuritic plaques and neurofibrillary tangles, suggesting a concurrent diagnosis of Alzheimer's disease. Cerebral angiogram did not suggest vasculitis and magnetic resonance imaging showed generalized cerebral atrophy supporting the diagnosis of Alzheimer's. This case illustrates that Alzheimer's dementia and PACNS can coexist in a single patient and that Alzheimer's disease should be considered when a patient with successfully treated PACNS presents with cognitive decline months or years after initial diagnosis.

Subclinical sensory neuropathy in late-onset restless legs syndrome

OBJECTIVE

To determine the prevalence of different forms of peripheral neuropathy in patients with restless legs syndrome (RLS) and correlate the findings with other clinical characteristics.

BACKGROUND

RLS is characterized by a desire to move the extremities, often associated with paresthesias or dysesthesias, motor restlessness, worsening of symptoms with rest with relief by activity, and worsening of symptoms in the evening or night. The association between RLS and peripheral neuropathy remains controversial. The observation that many patients with small-fiber neuropathy also complain of RLS prompted this prospective case series.

METHODS

Twenty-two consecutive patients with RLS were evaluated for evidence of large-fiber neuropathy (LFN) and small sensory fiber loss (SSFL).

RESULTS

In eight of the 22 (36%) patients, neuropathy was identified. Three patients had pure LFN; two had mixed LFN and SSFL; and three had isolated SSFL. The SSFL group had a later onset of RLS (p < 0.009), reported pain in their feet with RLS more frequently (p < 0.001), and tended to have no family history of RLS (p < 0.078). Patients with LFN did not have similar associations with age at onset, family history status, or presence of pain.

CONCLUSION

The results suggest that two forms of RLS exist: one is triggered by painful dysesthesias associated with SSFL, has later onset, and no family history; and one without involvement of SSF, with an earlier onset age, positive family history for RLS, and no pain. The authors hypothesize that patients with the SSFL subtype of RLS will preferentially respond to neuropathic pain medications.

Matrix metalloprotease-9 release from monocytes increases as a function of differentiation: implications for neuroinflammation and neurodegeneration

Naïve monocytes extravasate in response to monocyte chemoattractant-1 (MCP-1) and subsequently, following differentiation within tissue, carry out effector functions. Consistent with this concept, expression of the MCP-1 receptor CCR2 decreases with monocyte differentiation, as production of cytokines increases (Fantuzzi et al., 1999). Because matrix metalloproteases (MMPs) may also play an important role in the ability of monocytes to migrate into tissues and/or to promote pathogen clearance/tissue injury, we have examined production of matrix metalloprotease-9 as a function of both monocyte differentiation in vitro and expression of CCR2. Increased time in culture, which is linked to monocyte differentiation, resulted in enhanced production of MMP-9, assessed by gelatin substrate zymography. Further, CCR2-negative monocytes produced greater quantities of MMP-9 than did naïve CCR2-positive cells. Our results indicate that MMP-9 release increases during monocyte differentiation, consistent with a prominent role in effector functions. Because extracellular matrix proteins are important to cell structure and survival (Wee Yong et al., 1998), increased expression of MMP-9 could contribute to tissue damage following monocyte differentiation.

Lentivirus infection in the brain induces matrix metalloproteinase expression: role of envelope diversity

Infection of the brain by lentiviruses, including human immunodeficiency virus (HIV) and feline immunodeficiency virus (FIV), causes inflammation and results in neurodegeneration. Molecular diversity within the lentivirus envelope gene has been implicated in the regulation of cell tropism and the host response to infection. Here, we examine the hypothesis that envelope sequence diversity modulates the expression of host molecules implicated in lentivirus-induced brain disease, including matrix metalloproteinases (MMP) and related transcription factors. Infection of primary macrophages by chimeric HIV clones containing brain-derived envelope fragments from patients with HIV-associated dementia (HAD) or nondemented AIDS patients (HIV-ND) showed that MMP-2 and -9 levels in conditioned media were significantly higher for the HAD clones. Similarly, STAT-1 and JAK-1 levels were higher in macrophages infected by HAD clones. Infections of primary feline macrophages by the neurovirulent FIV strain (V(1)CSF), the less neurovirulent strain (Petaluma), and a chimera containing the V(1)CSF envelope in a Petaluma background (FIV-Ch) revealed that MMP-2 and -9 levels were significantly higher in conditioned media from V(1)CSF- and FIV-Ch-infected macrophages, which was associated with increased intracellular STAT-1 and JAK-1 levels. The STAT-1 inhibitor fludarabine significantly reduced MMP-2 expression, but not MMP-9 expression, in FIV-infected macrophages. Analysis of MMP mRNA and protein levels in brain samples from HIV-infected persons or FIV-infected cats showed that MMP-2 and -9 levels were significantly increased in lentivirus-infected brains compared to those of uninfected controls. Elevated MMP expression was accompanied by significant increases in STAT-1 and JAK-1 mRNA and protein levels in the same brain samples. The present findings indicate that two lentiviruses, HIV and FIV, have common mechanisms of MMP-2 and -9 induction, which is modulated in part by envelope sequence diversity and the STAT-1/JAK-1 signaling pathway.

A placebo-controlled trial of lamotrigine for painful HIV-associated neuropathy

OBJECTIVE

To investigate the analgesic efficacy of lamotrigine in the treatment of painful HIV-associated distal sensory polyneuropathy (DSP).

BACKGROUND

The pathogenesis of HIV-associated DSP is unknown and there is no effective treatment. A novel anticonvulsant, lamotrigine, blocks voltage-sensitive sodium channels and inhibits the release of glutamate and aspartate. There have been anecdotal reports of efficacy of lamotrigine in the treatment of painful neuropathy and trigeminal neuralgia.

METHODS

In a multicenter, randomized, double-blind, placebo-controlled study, lamotrigine was initiated at 25 mg per day and slowly titrated over 7 weeks to 300 mg per day. Study duration was 14 weeks. The primary outcome measure was change in pain on the modified Gracely scale with secondary outcome measures including change in neurologic examination, use of concomitant analgesic medications, and global pain relief.

RESULTS

Of 42 enrolled subjects, 13 did not complete the 14-week study endpoint. In five of these, rash was the cause for dropout. In the remaining 29 evaluable subjects, 20 patients received placebo and 9 received lamotrigine. The pain scores at baseline were not significantly different. The reduction in average pain from baseline to week 14 was greater (p = 0.03) in the lamotrigine group (-0.55) than in the placebo group (-0.18), adjusting for baseline levels of pain. There was no difference between the groups on the change in peak worst pain.

CONCLUSIONS

In this small trial, lamotrigine showed promise in the treatment of pain associated with HIV-related DSP. The frequency of rash was greater than in lamotrigine studies in epilepsy. A larger controlled study of lamotrigine is warranted.

Cytotoxicity by matrix metalloprotease-1 in organotypic spinal cord and dissociated neuronal cultures

Extracellular matrix (ECM) proteins, including collagens and laminins, are critical to the structure of the neuronal synapse and may also be involved in cell survival. In the present study, we therefore examined the possibility that select ECM degrading proteins might be toxic to organotypic spinal cord and dissociated neuronal cultures. Of those proteins tested, including MMP-1, -7, and -9, we observed that MMP-1 was toxic to spinal cord cultures as determined by release of lactic acid dehydrogenase as well as uptake of propidium iodide. Pretreatment of cell cultures with 50 microM alpha-tocopherol partially reversed these effects. We also observed that MMP-1 was toxic to human neurons grown in dissociated cultures and that increased amounts of MMP-1 were released by astrocytes following their stimulation with IL-1beta. These results suggest that further studies may be warranted to determine whether MMP-1 contributes to neurodegenerative conditions in which activated astrocytes may play a role.

Analysis of human immunodeficiency virus type 1 gp160 sequences from a patient with HIV dementia: evidence for monocyte trafficking into brain

Towards understanding the pathogenesis of HIV dementia, we molecularly cloned and sequenced human immundeficiency virus type 1 (HIV-1) gp160 genes from uncultured post-mortem tissues collected from a patient with HIV dementia. Sequences from bone marrow, lymph node, lung, and four regions of brain - the deep white matter, head of caudate, choroid plexus and meninges - were compared. Also included were gp160 sequences recovered from blood monocytes collected 5 months prior to death. Phylogenetic analyses showed that the sequences from deep white matter were more closely related to those from bone marrow, than to those from the other tissues, and moreover, were most closely related to sequences from the blood monocytes. These findings suggest trafficking of bone marrow-derived monocytes into the deep white matter during this late stage of infection. Another cluster included sequences from choroid plexus, meninges and lymph node, and interestingly, identical patterns of four or nine stop codons were shared among these tissues. These mutations appear to be the consequence of G-->A hypermutation, and could reflect independent events, or the movement of virions or infected cells, from the choroid plexus into the cerebrospinal fluid and ultimately, into the lymph node. We propose that a critical step towards the development of HIV dementia is an increase in monocyte trafficking into the brain, and that this process is either initiated and/or accelerated during late-stage infection, which could explain why dementia occurs primarily during this time.

Human immunodeficiency virus-associated dementia

HIV-associated dementia will eventually develop in 15-20% of individuals with advanced HIV disease. It has become one of the leading causes of dementia in the young, with 10,000 new cases annually in the USA. The clinical syndrome includes progressive development of psychomotor slowing and memory impairment, eventually with brain atrophy and neurol loss. The pathology is characterized by infection of macrophages and microglia, marked activation of macrophages, and release of a variety of postinflammatory cytokines into the parenchyma. Antiretroviral therapy has impacted positively on the incidence rates, and at least partial reversal of neurologic deficits can be achieved in established dementias.

A phase II trial of nerve growth factor for sensory neuropathy associated with HIV infection. AIDS Clinical Trials Group Team 291

OBJECTIVE

To evaluate the safety and efficacy of recombinant human nerve growth factor (rhNGF) in HIV-associated sensory neuropathy (SN) within a multicenter, placebo-controlled, randomized trial (ACTG 291).

BACKGROUND

SN affects 30% of individuals with AIDS, is worsened by neurotoxic antiretrovirals, and its treatment is often ineffective. NGF is trophic for small sensory neurons and stimulates the regeneration of damaged nerve fibers.

METHODS

A total of 270 patients with HIV-associated SN were randomized to receive placebo, 0.1 microg/kg rhNGF, or 0.3 microg/kg rhNGF by double-blinded subcutaneous injection twice weekly for 18 weeks. The primary outcome was change in self-reported neuropathic pain intensity (Gracely Pain Scale). Secondary outcomes included an assessment of global improvement in neuropathy by patients and investigators, neurologic examination, use of prescription analgesics, and quantitative sensory testing. In a subset, epidermal nerve fiber densities were determined in punch skin biopsies.

RESULTS

Both doses of NGF produced significant improvements in average and maximum daily pain compared with placebo. Positive treatment effects were also observed for global pain assessments (p = 0.001) and for pin sensitivity (p = 0.019). No treatment differences were found with respect to mood, analgesic use, or epidermal nerve fiber densities. Injection site pain was the most frequent adverse event, and resulted in unblinding in 39% of subjects. Severe transient myalgic pain occurred in eight patients, usually from accidental overdosing. There were no changes in HIV RNA levels or other laboratory indices.

CONCLUSIONS

We found a positive effect of recombinant human nerve growth factor on neuropathic pain and pin sensitivity in HIV-associated sensory neuropathy. rhNGF was safe and well tolerated, but injection site pain was frequent.

A pilot study evaluating ceftriaxone and penicillin G as treatment agents for neurosyphilis in human immunodeficiency virus-infected individuals

To compare intravenous (iv) ceftriaxone and penicillin G as therapy for neurosyphilis, blood and CSF were collected before and 14-26 weeks after therapy from 30 subjects infected with human immunodeficiency virus (HIV)-1 who had (1) rapid plasma reagin (RPR) test titers >/=1&rcolon;16, (2) reactive serum treponemal tests, and (3) either reactive CSF-Venereal Disease Research Laboratory (VDRL) tests or CSF abnormalities: (a) CSF WBC values >/=20/microL or (b) CSF protein values >/=50 mg/dL. At baseline, more ceftriaxone recipients had skin symptoms and signs (6 [43%] of 14 vs. 1 [6%] of 16; P=.03), and more penicillin recipients had a history of neurosyphilis (7 [44%] of 16 vs. 1 [7%] of 14; P=.04). There was no difference in the proportion of subjects in each group whose CSF measures improved. Significantly more ceftriaxone recipients had a decline in serum RPR titers (8 [80%] of 10 vs. 2 [13%] of 15; P=. 003), even after controlling for baseline RPR titer, skin symptoms and signs, or prior neurosyphilis were controlled for. Differences in the 2 groups limit comparisons between them. However, iv ceftriaxone may be an alternative to penicillin for treatment of HIV-infected patients with neurosyphilis and concomitant early syphilis.

Incidence of neuropathy in HIV-infected patients on monotherapy versus those on combination therapy with didanosine, stavudine and hydroxyurea

BACKGROUND

Sensory neuropathy is a common adverse effect of the nucleoside analogue anti-retroviral drugs didanosine (ddl) and stauvudine (d4T). These drugs are increasingly being used in combination, and it is not currently known whether the incidence of neuropathy is higher with combination compared to individual drug use. It is also not known if hydroxyurea, used to potentiate the antiviral efficacy of these drugs, may also increase the risk of neuropathy. The purpose of this analysis is to investigate if the combination of ddl and d4T, with or without hydroxyurea, has a higher incidence of neuropathy than a single drug regimen.

METHODS

Data were obtained from patients followed longitudinally by the Johns Hopkins AIDS Services. Incidence rates of development of neuropathy were calculated for each of five regimens: ddl (+/- hydroxyurea), ddl + d4T (+/- hydroxyurea), and d4T. Cox proportional hazard regression was used to compare the relative risk of neuropathy for each regimen adjusting for CD4 cell count, other drugs received, and time on therapy.

RESULTS

A total of 1116 patients received at least one of the five regimens. There were 117 cases of neuropathy. The crude incidence rate of neuropathy ranged from 6.8 cases per 100 person-years for ddl to 28.6 cases per 100 person-years for ddl + d4T + hydroxyurea. Compared with ddl alone, and adjusting for CD4 cell counts and other variables, the relative risk of neuropathy was 1.39 [95% confidence interval (CI): 0.84-2.32] for d4T alone, 2.35 (95% CI: 0.69-8.07) for ddl + hydroxyurea, 3.50 (95% CI: 1.81-6.77) for ddl + d4T, and 7.80 (95% CI: 3.92-15.5) for ddl + d4T + hydroxyurea.

CONCLUSIONS

Based on the data, the risk of neuropathy is additive or even synergistic for ddl + d4T + hydroxyurea compared with ddl or d4T alone. The combination of ddl + d4T also increases the risk of neuropathy but less than when hydroxyurea is included.

Improvement in HIV-associated motor slowing after antiretroviral therapy including protease inhibitors

A study of neuropsychological performance was conducted in 33 HIV+ patients initiating highly active antiretroviral therapy (HAART). Grooved Pegboard (GP) non-dominant hand performance improved in 23/33 (70%) subjects (P=0.002). Among 23 patients with motor slowing (GP non-dominant hand z score < -1.0) at baseline, 18 (78%) improved on the GP non-dominant hand test after initiating HAART (P=0.001). GP non-dominant hand performance improved longitudinally in HIV+ patients initiating HAART, while matched HIV+ controls not on HAART did not change (P=0.045). Significant improvement in motor performance can occur after HAART in HIV+ patients with impairment.

Transdermal selegiline in HIV-associated cognitive impairment: pilot, placebo-controlled study

The authors conducted a pilot randomized, double-blind, placebo-controlled clinical trial of the transdermal administration of selegiline in HIV+ patients to obtain preliminary data to assess its safety, tolerability, and impact on HIV-associated cognitive impairment. Both selegiline and placebo were well tolerated with few adverse events. Improvements favoring the selegiline group were suggested on single tests of verbal memory and motor/psychomotor performance, warranting a larger study.

Epidermal nerve fiber density and sural nerve morphometry in peripheral neuropathies

OBJECTIVE

To study intraepidermal nerve fiber (IENF) density in distal leg skin biopsies, sural nerve morphometry, electrophysiology, and clinical features in patients with peripheral neuropathies.

METHODS

We studied 26 patients with neuropathic complaints who had undergone clinical evaluation, nerve conduction studies, distal leg skin biopsy, and sural nerve biopsy. We quantified densities of IENF and of myelinated and unmyelinated fibers in the sural nerve. Associations among skin and sural nerve morphometric measures and sensory nerve action potential (SNAP) amplitudes were examined nonparametrically. Morphometric measures were examined with respect to diagnostic category of neuropathy.

RESULTS

IENF density correlated with the densities of sural nerve total myelinated (r = 0.57, p = 0.0011), small myelinated (r = 0.53, p = 0.0029), and large myelinated fibers (r = 0.49, p = 0.0054). There was a trend toward an association between IENF and sural nerve unmyelinated fiber densities (r = 0.32, p = 0.054). Sural SNAP amplitude and large myelinated fiber densities were highly correlated (r = 0.87, p < 0.0001). IENF density and sural nerve small fiber measures were concordant in 73% of patients. Reduced IENF density was the only indicator of small fiber depletion in 23% of cases. It was usually normal in acquired demyelinating neuropathies and where clinical suspicion for neuropathy was low.

CONCLUSIONS

Distal leg Intraepidermal nerve (IENF) density may be more sensitive than sural nerve biopsy in identifying small fiber sensory neuropathies. Assessments of IENF density and large fiber measures on biopsy and electrophysiology are both useful for characterizing sensory and sensorimotor neuropathies.

Progressive multifocal leukoencephalopathy in AIDS: are there any MR findings useful to patient management and predictive of patient survival? AIDS Clinical Trials Group, 243 Team

BACKGROUND AND PURPOSE

While MR findings in progressive multifocal leukoencephalopathy (PML) have been described previously, usually in retrospective studies with limited sample size, what has not been well addressed is whether any are predictive of longer survival. Our participation in a large prospective clinical trial of AIDS patients with biopsy-proved PML and MR correlation allowed us to test our hypothesis that certain MR features could be found favorable to patient survival.

METHODS

The patient cohort derived from a randomized multicenter clinical trial of cytosine arabinoside for PML. Pretreatment T1- and T2-weighted noncontrast images (n = 48) and T1-weighted contrast-enhanced images (n = 45) of 48 HIV-positive patients with a PML tissue diagnosis as well as the follow-up images in 15 patients were reviewed to determine signal abnormalities, lesion location and size, and the presence or absence of mass effect, contrast enhancement, and atrophy, and to ascertain the frequency of these findings. A statistical analysis was performed to determine if any MR abnormalities, either at baseline or at follow-up, were predictive of patient survival.

RESULTS

No MR abnormalities either on univariate or multivariate analysis significantly correlated with patient survival, with the exception of mass effect, which was significantly associated with shorter survival. The mass effect, however, always minimal, was infrequent (five of 48). More severe degrees of cortical atrophy and ventricular dilatation, lesion location and size, and other MR variables were not predictive of outcome.

CONCLUSION

Except for mass effect, we found no MR findings predictive of the risk of death in patients with PML. The mass effect, however, was so infrequent and minimal that it was not a useful MR prognostic sign.

A decision guideline for emergency department utilization of noncontrast head computed tomography in HIV-infected patients

OBJECTIVE

To determine which neurologic signs or symptoms are predictive of new focal lesions on head CT in HIV-infected patients.

METHODS

Prospective study with convenience sample enrollment of HIV-infected patients who presented to a large inner-city university-based ED over an 11-month period. Patients were assessed using a standardized neurologic evaluation to ascertain whether they had developed new or changed neurologic signs or symptoms. Patients with any new or changed neurologic findings had a head CT scan in the ED. The association between individual complaints or findings and new focal lesions on head CT was assessed by univariate analysis, and sensitivity, specificity, and positive predictive values were calculated. Stepwise logistic regression analysis was then carried out to estimate the relative risk for those variables independently associated with new focal lesions on CT scans. A decision guideline was developed incorporating those variables.

RESULTS

One hundred ten patients were identified as having new or changed neurologic signs or symptoms and had a head CT done in the ED. Twenty-seven patients (24%) had focal lesions on head CT, of which 19 (18%) were identified as new focal lesions; eight of these (7%) demonstrated a mass effect. Clinical findings most strongly associated with new focal findings on head CT were: 1) new seizure, relative risk (RR) = 73.5, 95% CI = 6.2 to 873.0; 2) depressed or altered orientation, RR = 39.1, 95% CI = 4.6 to 330.0; and 3) headache, different in quality, RR = 27.0, 95% CI = 3.2 to 230.1. Use of these three findings as a screen for ordering head CT in the ED would have identified 95% (18/19) of the patients with new focal intracranial lesions, and resulted in a 53% reduction in the number of head CTs ordered in the ED. Inclusion of one additional parameter (prolonged headache, > or =3 days), would have resulted in identification of 100% of all new focal lesions, with a 37% reduction in the number of head CTs ordered. Among those patients with new focal findings, 74% required emergent management (i.e., seizure control, IV antibiotics, IV steroids or surgery). The most common intracranial lesion among patients with CD4 counts less than 200 cells/microL was toxoplasmosis, while cerebrovascular accidents (ischemic or hemorrhagic) were most common in those with CD4 counts greater than 200 cells/microL.

CONCLUSION

Specific clinical signs and symptoms were associated with the presence of new intracranial lesions in a group of HIV-infected patients who presented to the ED with neurologic complaints. These clinical findings can be incorporated into guidelines for determining the need for emergent head CT. Validation and widespread application of these guidelines could result in limiting the use of emergent neuroimaging to a more well-defined HIV-infected patient population.

Cerebrospinal fluid levels of MMP-2, 7, and 9 are elevated in association with human immunodeficiency virus dementia

Pathological evidence suggests that alterations of the blood-brain barrier (BBB) may occur in association with human immunodeficiency virus (HIV) dementia (HIVD). Increased BBB permeability could contribute to the development of dementia by facilitating the entry of activated and infected monocytes, as well as potentially toxic serum proteins, into the central nervous system. One mechanism by which BBB permeability may be altered is through increased activity of select matrix metalloproteinases (MMPs). In the present study, we examined the possibility that MMPs that target critical BBB proteins, including laminin, entactin, and collagen type IV, are elevated in the cerebrospinal fluid (CSF) of patients with HIVD. We also examined the possibility that such MMPs could be produced by brain-derived cells, and that MMP production by these cells might be increased by tumor necrosis factor-alpha, an inflammatory cytokine that is produced by HIV-infected monocytes/microglia and is elevated in HIVD. By using western blot and enzyme-linked immunosorbent assay, we observed that CSF levels of pro-MMP-2 and pro-MMP-7 were increased in association with HIVD. In addition, through the use of gelatin substrate zymography, a sensitive functional assay for MMP-2 and MMP-9, we observed that MMP-2 or pro-MMP-9 activity was more frequently detectable in the CSF of individuals with HIV dementia (9/16) than in the CSF from either nondemented seropositive (2/11) or seronegative (0/11) controls. Although the presence of MMPs in the serum could contribute to elevated levels in the CSF, we also show that brain-derived cells release MMP-2, 7, and 9, and that such release is increased after their stimulation with tumor necrosis factor-alpha. Together, these results suggest that elevated CSF levels of select MMPs may reflect immune activation within the central nervous system. They also suggest that further studies may be warranted to determine whether these proteins may play a role in the development of symptomatic neurological disease.

Randomized trial of the platelet-activating factor antagonist lexipafant in HIV-associated cognitive impairment. Neurological AIDS Research Consortium

OBJECTIVE

To assess the safety and tolerability of lexipafant in HIV-associated cognitive impairment.

BACKGROUND

Cognitive impairment is the most common neurologic complication of advanced HIV-1 infection. There is evidence that a variety of inflammatory mediators, including platelet-activating factor (PAF), may contribute to neuronal injury. We hypothesized that lexipafant, a PAF antagonist, might improve cognitive dysfunction in HIV-infected people.

METHODS

We conducted a randomized, double-blind, placebo-controlled clinical trial to assess the safety and tolerability of lexipafant 500 mg/day. The primary outcome measure for tolerability was the ability to complete the study on the originally assigned dosage of medication. Thirty patients with cognitive impairment were enrolled.

RESULTS

Lexipafant was safe and well tolerated. Ninety-three percent in the placebo group and 88% in the lexipafant group completed the study at the originally assigned dosage. Trends toward improvement were seen in neuropsychological performance, especially verbal memory, in the lexipafant treatment group.

CONCLUSIONS

This study shows that lexipafant, the first PAF antagonist used in HIV-associated cognitive impairment, is a safe and well tolerated compound. The observed trends toward improvement in neuropsychological test scores warrant the pursuit of a larger and longer efficacy trial to assess the impact of lexipafant on cognitive performance.

Combination antiretroviral therapy improves psychomotor speed performance in HIV-seropositive homosexual men. Multicenter AIDS Cohort Study (MACS)

BACKGROUND

Combination antiretroviral therapy including protease inhibitors (combo+PI) is effective in suppressing systemic viral load in HIV infection, but its impact on HIV-associated cognitive impairment is unclear.

OBJECTIVE

To determine whether psychomotor speed, a sensitive measure of impairment in HIV dementia, improves with combo+PI compared with other antiretroviral treatments.

METHODS

A total of 411 HIV-seropositive (HIV+) homosexual men (with longitudinal neuropsychological testing) in the Multicenter AIDS Cohort Study and, in a separate analysis, 282 HIV+ homosexual men with psychomotor slowing at baseline were classified by treatment into four groups: antiretroviral naive (no antiretroviral medication treatment), monotherapy, combination antiretroviral therapy without protease inhibitors (combo-noPI), and combo+PI. We compared longitudinal performance on three tests of psychomotor speed: the Grooved Pegboard (GP) (nondominant and dominant hands), Trail Making Test B, and the Symbol Digit Modalities Test (SDMT).

RESULTS

Relative to antiretroviral-naïve and monotherapy participants, on the GP nondominant hand test, combo+PI participants with abnormal baseline neuropsychological testing showed improved performance (difference = +0.63 standard deviation [SD], p = 0.02). For the SDMT, both combo+PI participants (difference = +0.26 SD, p = 0.03) and combo-noPI participants (difference = +0.29 SD, p = 0.01) with abnormal baseline neuropsychological testing improved compared with antiretroviral-naïve and monotherapy groups.

CONCLUSION

Combo+PI and combo-noPI are associated with improved psychomotor speed performance in HIV+ homosexual men with abnormal neuropsychological testing.

Quantitative analysis of epidermal innervation in Fabry disease

OBJECTIVE

To use skin biopsy specimens to quantitate the cutaneous innervation density of Fabry patients who had preserved renal function.

BACKGROUND

The small fiber neuropathy of Fabry disease is difficult to detect and quantitate by conventional methods. Because this neuropathy is a common characteristic of Fabry disease, quantitating changes in this parameter would be helpful in demonstrating the effectiveness of enzyme or gene replacement therapy.

METHODS

Patients underwent skin biopsy at the thigh and foot. Innervation density was determined by counting free nerve endings in the epidermis. These data were compared with nerve conduction studies, and in selected patients, fiber quantitation of sural nerve biopsy specimens.

RESULTS

The Fabry patients had normal results of nerve conduction studies and large fiber quantitation by sural nerve biopsy. However, the involvement of small cutaneous fibers in these patients was easily demonstrable and quantifiable by skin biopsy. All patients showed severe loss of intraepidermal innervation at the ankle, but fiber loss at the distal thigh was proportionately less severe.

CONCLUSIONS

The nerve damage in Fabry patients with preserved renal function involves exclusively small myelinated and unmyelinated fibers, and skin biopsy is a useful in detecting and quantitating such damage. Comparison of cutaneous innervation density with quantitation of sural nerve biopsy specimens demonstrated that skin biopsy specimens were as sensitive in detecting the presence of neuropathy as were the nerve specimens. It is speculated that analysis of cutaneous innervation may provide a useful marker of the nervous system's response to specific therapy for Fabry disease.

Epidermal innervation: changes with aging, topographic location, and in sensory neuropathy

In previous work we demonstrated little effect of aging on the density and spatial pattern of epidermal innervation, however, this was restricted to two sites proximal and distal in the leg. To expand on these observations, we used punch skin biopsy in ten healthy controls to examine the variation in intra-epidermal nerve fiber (IENF) density at multiple specific sites in the leg. There was a consistent gradient in IENF from proximal to distal sites in all subjects, but minimal effect of age was noted. In the older age group (> or =70 years), the IENF densities ranged from 28.6+/-1.9 IENF/mm at the trunk to 15.5+/-1.5 at the distal leg. In a group of six patients with painful sensory neuropathy, we confirmed a length-dependent reduction in IENF. We observed what may be a predegenerative change, namely increased branching of epidermal nerve fibers at clinically unaffected sites. These data suggest little age-related change in IENF, at least up to age 75 years, in healthy normals. The increased branching complexity noted in unaffected sites in patients with sensory neuropathies implies that this may be a predegenerative change, preceding the actual loss of nerve fibers. Skin biopsy may be a useful tool for assessing the topographic extent and degree of nerve fiber damage in sensory neuropathies and its quantitative interpretation should be little affected by aging changes.

Plasma viral load and CD4 lymphocytes predict HIV-associated dementia and sensory neuropathy

OBJECTIVE

To determine the predictive value of plasma HIV RNA and CD4 lymphocytes for HIV-associated dementia and sensory neuropathy.

METHODS

A total of 1,604 AIDS-free HIV seropositive men from the Multicenter AIDS Cohort Study were followed over a 10-year period (1985 to 1995). HIV-associated dementia and sensory neuropathy were diagnosed according to standard definitions. Baseline samples were used to measure plasma HIV RNA levels with a branched DNA assay and levels of beta2-microglobulin, CD4 lymphocyte counts, and hemoglobin levels.

RESULTS

Seventy-seven patients with HIV-associated dementia and 213 patients with sensory neuropathy were identified. Baseline HIV RNA levels above 3,000 copies/mL and CD4 counts below 500 cells/mm3 were predictive of both neurologic outcomes, but neither hemoglobin, body mass index, nor beta2-microglobulin were independently predictive. After adjusting for age and level of education, individuals with baseline plasma HIV RNA >30,000 copies/mL had a relative hazard for dementia 8.5 times (p < 0.001) that of those with <3,000 copies/mL, and those with CD4 counts <200 cells/mm3 had a 3.5-fold (p = 0.003) greater hazard relative to those with CD4 counts >500 cells/mm3. Individuals with HIV RNA >10,000 copies/mL had a 2.3-fold (p = 0.008) greater hazard of sensory neuropathy than those with <500 copies/mL, and men with <750 CD4 cells/mm3 had a 1.4-fold (p = 0.03) greater hazard than those with >750 CD4 cells/mm3.

CONCLUSIONS

High levels of systemic HIV replication may "drive" the initiation of neurologic disease; effective suppression of HIV may reduce the incidence of dementia and neuropathy. Levels of plasma HIV RNA and CD4 counts, determined before the initiation of antiretroviral therapy, were predictive of HIV-associated dementia and sensory neuropathy.

HAART improves prognosis in HIV-associated progressive multifocal leukoencephalopathy

Introduction of highly active antiretroviral therapy (HAART) has been associated with many changes in the complications of human immunodeficiency virus (HIV) infection. A cohort of 25 HIV patients with progressive multifocal leukoencephalopathy (PML) treated with HAART experienced a median survival of >46 weeks. This is an improvement in prognosis compared with recent historic experience and correlated with HIV RNA viral load reductions. We conclude that current HIV therapy is important in improving the outlook of PML in the setting of HIV.

Rate and severity of HIV-associated dementia (HAD): correlations with Gp41 and iNOS

BACKGROUND

Fifteen to thirty percent of AIDS patients develop some type of neurologic disorder during the course of their illness and the vast majority of these neurologic disorders will be HIV-associated dementia (HAD). These patients can exhibit varying degrees of severity and rates of progression of HAD. Neuropathologic variables that are associated with the rate of progression of HAD are not known.

MATERIALS AND METHODS

Tissue was collected at autopsy from the Johns Hopkins University HIV Neurology Program. Seventy-one AIDS patients of this prospectively characterized population were followed until death to obtain information on dementia severity and the rate of neurological progression. Immunoblot analysis of immunological nitric oxide synthase (iNOS), HAM56, gp41, p24, gp120, and beta-tubulin was performed and the levels of iNOS, HAM56, gp41, and p24 were normalized to beta-tubulin and analyzed for significance by means of the Kruskal-Wallis test for multiple groups.

RESULTS

We have identified unique groups within this spectrum and designated them slow, moderate, and rapid progressors. Slow and moderate progressors' neurological progression occurs over a course of months to years, whereas the rapid progressors' disease shows rapid increases in severity over weeks to months. In the present study we demonstrate that the severity and rate of progression of HAD correlates significantly with levels of the HIV-1 coat protein, gp41, iNOS, and HAM56, a marker of microglial/macrophage activation.

CONCLUSION

The severity and rate of progression of HAD correlates with indices of immune activation as well as levels of iNOS and gp41. There appears to be a threshold effect in which high levels of gp41, iNOS, and immune activation are particularly associated with severe (Memorial Sloan-Kettering score 3 to 4) and rapidly progressive HAD.

HIV-associated primary CNS lymorbidity and utility of brain biopsy

INTRODUCTION

Human immunodeficiency virus (HIV) infection is associated with several central nervous system (CNS) infections and neoplasms. These opportunistic processes generally occur with advanced immunosuppression, but if an accurate diagnosis is made, effective treatment can frequently be initiated.

METHODS

In an attempt to assess the safety, diagnostic yield, and utility of stereotactic brain biopsy in the clinical management of suspected HIV-associated primary CNS lymphoma, we retrospectively studied the performance of biopsy in HIV-seropositive patients presenting with focal intracranial lesions. This analysis included 435 patients undergoing brain biopsy, identified through a local case series (n=47) combined with all published cases (n=388). The years of analysis for this study were 1984 and 1997. We also assessed the survival of HIV-associated intracranial mass lesions and of PCNSL patients treated at JHU.

RESULTS

Definitive histopathological diagnoses were established in eighty-eight percent of biopsied cases: primary CNS lymphoma (PCNSL) (30%), CNS toxoplasmosis (CNS TOXO) (16%), progressive multifocal leukoencephalopathy (PML) (25%), and other specific diagnoses (17%). Post-biopsy morbidity within thirty days was 8.4% and mortality was 2.9%. PCNSL was the most common diagnosis among cases biopsied after failure of anti-toxoplasmosis therapy, 134/205 (65%). In the local case series, biopsy-related morbidity was associated with poor functional status, decreased platelet count, and number of lesions at presentation. The median survival of irradiated PCNSL cases was 29 days longer than untreated cases (median survival 50 days versus 21 days, respectively, Chi-square=6.73, P<0.01).

DISCUSSION

Stereotactic brain biopsy had a high diagnostic yield for HIV-associated focal intracranial lesions, however, the biopsy complication rate in this patient population was relatively high. PCNSL was diagnosed in the majority of patients failing anti-toxoplasmosis therapy. Survival after irradiation for PCNSL remains very poor.

Epidermal nerve fiber density: normative reference range and diagnostic efficiency

BACKGROUND

The sensitivity of neuron-specific antibodies permit the identification of the small unmyelinated nerve fibers within the skin.

OBJECTIVES

To develop a reference range of epidermal nerve fiber density in humans, and to evaluate their diagnostic efficiency for sensory neuropathies.

METHODS

Ninety-eight normal controls (age range, 13-82 years) were examined with both directed neurologic examinations and quantitative sensory testing. The diagnostic utility was examined in 20 patients with sensory neuropathies. Each subject had 2 punch biopsies performed at each site in the thigh and distal part of the leg (total of 392 biopsies). After formalin fixation, 50-microm-thick free-floating sections were stained with a polyclonal antibody to neuron-specific ubiquitin hydrolase, anti-protein gene product 9.5. We enumerated intraepidermal nerve fibers per millimeter to derive a "linear density." The linear density technique was validated against a stereological technique that used the fractionator to measure the total length of intraepidermal nerve fibers per 3-mm punch.

RESULTS

The biopsy technique was well tolerated, with no notable complications. The linear density quantitation was rapid and had high intraobserver and interobserver reliability. We determined that the density of intraepidermal fibers in normal controls was 21.1+/-10.4 per millimeter (mean +/- SD) in the thigh (fifth percentile, 5.2 per millimeter), and was 13.8+/-6.7 per millimeter at the distal part of the leg (fifth percentile, 3.8 per millimeter). Significantly higher intraepidermal fiber densities were seen in the youngest group (P = .004), and we observed no significant effect of race, sex, height, or weight. The density at the thigh was significantly correlated with that at the distal part of the leg (P = .01) and was consistently higher by about 60%, a reflection of the normal proximal-distal gradient. The results obtained with stereology and the linear density correlated significantly (P=.001), providing internal validation for the technique. Epidermal nerve fiber density was significantly reduced (P = .001) in patients with sensory neuropathies. With a cutoff derived from the fifth percentile of the normative range for the distal part of the leg, the technique had a positive predictive value of 75%, a negative predictive value of 90%, and a diagnostic efficiency of 88%.

CONCLUSIONS

We have established a reference range for intraepidermal nerve fiber density in normal humans by means of a simple quantitation method based on enumeration of individual intraepidermal nerve fibers on vertical sections of punch skin biopsy specimens stained with the sensitive panaxonal marker anti-protein gene product 9.5. The utility of the density measurement was confirmed for sensory neuropathy with a diagnostic efficiency of 88%. Skin biopsies may be useful to assess the spatial distribution of involvement in peripheral nerve disease and the response to neurotrophic and other restorative therapies.

Neuropathological alterations in diabetic truncal neuropathy: evaluation by skin biopsy

OBJECTIVES

To describe the neuropathological features in skin biopsies from patients with diabetic truncal neuropathy.

METHODS

Three patients with diabetic truncal neuropathy underwent skin biopsies from both symptomatic and asymptomatic regions of the chest and trunk. After local anaesthesia, biopsies were performed using a 3 mm diameter punch device (Acupunch). Intraepidermal nerve fibres (IENFs), the most distal processes of small myelinated and unmyelinated nerve fibres, were identified after staining with PGP 9.5 as previously described.

RESULTS

Diabetes was diagnosed at the time of the neurological presentation in two, and one was a known diabetic patient. All three had associated sensory-motor polyneuropathy. In all, skin biopsies showed a marked reduction of both epidermal and dermal nerve fibres in the symptomatic dermatomes, compared with skin from asymptomatic truncal areas. In one patient, a follow up skin biopsy when symptoms had improved showed a return of IENFs.

CONCLUSIONS

In diabetic truncal neuropathy, skin biopsies from symptomatic regions show a loss of IENFs. After clinical recovery, there is a return of the IENF population, suggesting that improvement occurs by nerve regeneration. These findings suggest that sensory nerve fibre injury in diabetic truncal neuropathy is distal to or within the sensory ganglia. Skin biopsy provides a possible tool for understanding the pathophysiology of the disease.

Neuronal death induced by brain-derived human immunodeficiency virus type 1 envelope genes differs between demented and nondemented AIDS patients

Human immunodeficiency virus type 1 (HIV-1) infection of the brain results in viral replication primarily in macrophages and microglia. Despite frequent detection of viral genome and proteins in the brains of AIDS patients with and without HIV dementia, only 20% of AIDS patients become demented. To investigate the role of viral envelope gene variation in the occurrence of dementia, we examined regions of variability in the viral envelope gene isolated from brains of AIDS patients. Brain-derived HIV-1 V1-V2 envelope sequences from seven demented and six nondemented AIDS patients displayed significant sequence differences between clinical groups, and by phylogenetic analysis, sequences from the demented group showed clustering. Infectious recombinant viruses containing brain-derived V3 sequences from both clinical groups were macrophagetropic, and viruses containing brain-derived V1, V2, and V3 sequences from both clinical groups spread efficiently in macrophages. In an indirect in vitro neurotoxicity assay using supernatant fluid from HIV-1-infected macrophages, recombinant viruses from demented patients induced greater neuronal death than viruses from nondemented patients. Thus, the HIV-1 envelope diversity observed in these patient groups appeared to influence the release of neurotoxic molecules from macrophages and might account in part for the variability in occurrence of dementia in AIDS patients.

Beta-chemokines MCP-1 and RANTES are selectively increased in cerebrospinal fluid of patients with human immunodeficiency virus-associated dementia

Human immunodeficiency virus-associated dementia (HAD) is associated with increased numbers of activated central nervous system (CNS) macrophages. Chemokines, which regulate infiltration of macrophages, were measured in the cerebrospinal fluid (CSF) of human immunodeficiency virus (HIV)-negative and HIV-positive individuals with and without neurological disease. Monocyte chemotactic protein (MCP)-1 and RANTES (but not MCP-3), macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, or interleukin-8 (IL-8) was higher in HAD. MCP-1 correlated with CSF viral load and severity of dementia, and it increased over time in patients who developed dementia.

Brain-derived HIV-1 tat sequences from AIDS patients with dementia show increased molecular heterogeneity

HIV-1 infection results in a dementing illness affecting 20% of patients with AIDS. Several HIV-1 genes have been implicated in the pathogenesis of HIV-induced neurological disease. To search for distinct HIV-1 sequences associated with the development of dementia, brain-derived tat, env, and pol sequences were examined from AIDS patients defined pre-mortem as demented (HIV-D)[n=5] or non-demented (HIV-ND)[n=5]. Estimations of evolutionary distances and frequency of non-synonymous mutation rates revealed significant differences between brain-derived tat, env, and pol-encoded reverse transcriptase sequences. However, established zidovudine-associated resistance mutations in reverse transcriptase sequences were identified in only one HIV-D and one HIV-ND patient despite prolonged treatment of some patients. Non-synonymous/synonymous substitution rates among the tat sequences derived from patients with HIV-D were significantly higher compared to the HIV-ND group (P < 0.001). The ratios of transversions to transitions were also significantly higher among the HIV-D tat sequences (P< 0.01). Phylogenetic analyses showed clustering of sequences from each clinical group among the brain-derived tat and env sequences. These studies indicated that differing selective forces act on individual HIV-1 genes in the brain which may influence the development of dementia.

A phase I/II trial of nimodipine for HIV-related neurologic complications

BACKGROUND

Few effective treatments are available for AIDS dementia complex (ADC) and HIV-associated neuropathy. However, recent in vitro studies indicate that nimodipine, a voltage-dependent calcium channel antagonist, can prevent HIV-related neuronal injury and may provide a novel form of treatment for these disorders.

METHODS

To determine the safety and possible efficacy of this agent, 41 patients with mild to severe ADC, including 19 patients with neuropathy, were entered into the AIDS Clinical Trial Group multicenter, phase-I and phase-II study. Nimodipine at 60 mg p.o., five times daily; 30 mg p.o., three times daily; or placebo was administered for 16 weeks as adjuvant treatment to antiretroviral therapy.

RESULTS

Neuropsychological performance at baseline, measured by the composite neuropsychological Z score (NPZ-8), correlated significantly with the ADC stage and with CSF levels of neopterin, a marker of immune activation. No significant differences in toxicity were observed among the three arms. Intent-to-treat analysis showed no significant change in the NPZ-8, although improvement was suggested in the high-dose arm. In addition, a trend toward stabilization in peripheral neuropathy was observed in both nimodipine arms compared with placebo.

CONCLUSIONS

Nimodipine and other similar nonantiretroviral agents may provide a safe and promising avenue of treatment for neurologic disorders associated with HIV infection. The results of this study indicate that further clinical trials are warranted.

Small-fiber sensory neuropathies: clinical course and neuropathology of idiopathic cases

We describe the clinical features, natural history, and neuropathology of 32 patients presenting with "burning feet," for whom no specific cause was identified. All had neuropathic pain in the feet and morphological abnormalities of cutaneous innervation in skin obtained using punch biopsy. Most (29) had an abnormal sensory examination. All had normal strength, proprioception, tendon reflexes, and nerve conductions. Two clinical patterns were apparent, based on natural history and spatial distribution of cutaneous denervation. Most (28) patients presented with neuropathic pain initially restricted to the feet and toes but extending more proximally to involve the legs and hands with time. Intraepidermal nerve fiber (IENF) density was most severely reduced distally, with more normal IENF densities in skin from proximal sites. In contrast, a minority (4) presented with the abrupt onset of generalized cutaneous burning pain and hyperesthesia. In these patients, IENF densities were reduced in skin from both proximal and distal sites. Absolute IENF densities in calf skin were reduced below the lower limit of normal (5th percentile) in 26 (81%). Of the 6 who underwent sural nerve biopsy, 4 had selective loss of small myelinated and/or unmyelinated axons and 2 had normal histology and fiber densities despite reduced IENF densities in skin biopsy specimens. Punch skin biopsy from proximal and distal sites is a useful means of assessing these distinctive patients and may provide further insight into pathophysiology.

Variable progression of HIV-associated dementia

A consecutive series of 71 patients diagnosed with HIV-associated dementia (HAD) (1984-1994) were studied to characterize the clinical course of HAD, and to identify predictive markers of rapid neurologic progression. Neurologic progression rate was determined from the change in the Memorial Sloan Kettering (MSK) dementia severity score from diagnosis to death. Those with the most rapid progression in neurologic disability were compared with those with slow or no progression. Autopsy material was immunostained for macrophage activation markers and gp41 in 30 individuals. Median survival was 3.3 months and 6.1 months for rapid-progression and no-progression patients, respectively. Rapid progression was associated with injection drug use but not with race, gender, or age. CD4+ cell counts were lower at diagnosis among rapid-progression than no-progression patients but no differences in AIDS-defining illnesses or patterns of antiretroviral therapy were found. At presentation, rapid-progression patients had more prominent symptoms of mental slowing than those with no progression; however, no other clinical features, CSF, or imaging features distinguished the groups. Less abundant macrophage activation in both basal ganglia and midfrontal gyrus regions, as judged by HAM56 immunostaining, was noted in 9 no-progression patients, compared with 12 rapid-progression patients. Neurologic progression and survival with HAD is highly variable. A significant proportion of individuals with dementia have prolonged survival of more than 12 months and remain cognitively stable. A history of injection drug use and presentation with prominent psychomotor slowing is associated with more rapid neurologic progression, and these patients tend to show more abundant macrophage activation within the CNS.

Survival prolongation in HIV-associated progressive multifocal leukoencephalopathy treated with alpha-interferon: an observational study

A retrospective chart review was conducted to determine the effect of alpha-Interferon (alpha-IFN) on disease progression, symptom palliation, and survival in HIV-associated Progressive Multifocal Leukoencephalopathy (PML).

METHODS

Subjects were HIV seropositive patients diagnosed with PML at the Johns Hopkins Hospital between 1985 and July of 1986. Diagnostic criteria for PML included both clinical symptomatology and histologic or radiographic confirmation. All patients with concomitant CNS infections were excluded. Patients receiving a minimum treatment of 3 weeks of 3 million units of alpha-IFN daily were compared to untreated historical controls. From 104 PML cases reviewed, 77 met the defined criteria for PML. Twenty-one patients had received open-label alpha-IFN treatment in a non-randomized manner for at least 3 weeks, and 32 met criteria for inclusion in the untreated group as historical controls. Deceased treated patients were comparable to deceased untreated patients with respect to age, gender, race, HIV risk factors, AIDS-defining illnesses, and CD4+ counts. CD4+ counts and use of anti-retroviral medications within 6 months of PML onset were higher among those who were living at the time of the study.

RESULTS

Among deceased patients, median survival of treated patients was 127.5 days longer than that of untreated patients (Chi-square=4.21, P=0.04). When living and deceased treated patients were combined, the median survival was 325 days (range 35 - 1634) versus 121 days (range 46 - 176) in untreated patients (Chi-square=13.47, P < 0.001). When survival times in untreated patients were left-censored to account for possible survivorship bias in treated patients, survival in treated patients remained significantly prolonged (325 days versus 175.5 days, Chi-square=4.65, P=0.03). In addition, use of alpha-IFN was associated with a significant delay in the onset of memory loss (Chi-square=8.59, P < 0.01). Seven alpha-IFN treated patients showed sustained remissions of several months to over a year, with documented improvements in mental status, aphasia, dysarthria, dysphagia, paresis, and dyscoordination. Moreover, four IFN-treated patients had evidence of MRI lesion regression, although this was not always correlated with clinical remission. Four of 32 untreated patients also reported transient symptomatic improvements.

CONCLUSION

This open-label study suggests that alpha-IFN may delay progression, palliate symptoms, and significantly prolong survival in HIV-associated PML, and we therefore suggest that a controlled clinical trial is warranted.

Induction of monocyte chemoattractant protein-1 in HIV-1 Tat-stimulated astrocytes and elevation in AIDS dementia

Activated monocytes release a number of substances, including inflammatory cytokines and eicosanoids, that are highly toxic to cells of the central nervous system. Because monocytic infiltration of the central nervous system closely correlates with HIV-1-associated dementia, it has been suggested that monocyte-derived toxins mediate nervous system damage. In the present study, we show that the HIV-1 transactivator protein Tat significantly increases astrocytic expression and release of monocyte chemoattractant protein-1 (MCP-1). Astrocytic release of beta-chemokines, which are relatively less selective for monocytes, including RANTES, macrophage inflammatory protein-1alpha, and macrophage inflammatory protein-1beta, was not observed. We also show that MCP-1 is expressed in the brains of patients with HIV-1-associated dementia and that, of the beta-chemokines tested, only MCP-1 could be detected in the cerebrospinal fluid of patients with this condition. Together, these data provide a potential link between the presence of HIV-1 in the brain and the monocytic infiltration that may substantially contribute to dementia.

Sustained cognitive decline in HIV infection: relationship to CD4+ cell count, plasma viremia and p24 antigenemia

To determine the clinical and virological correlates of neuropsychological test performance decline in HIV infection, we measured viral burden in blood in 272 HIV-seropositive men without dementia in the Baltimore arm of the Multicenter AIDS Cohort Study (MACS). These measures were then related to neuropsychological (NP) decline, defined as a decline relative to prior best performance of 2.0 standard deviations or more on one or more neuropsychological tests. A short battery of NP tests (Mini-Screen Battery) was administered to all 272 men. NP test performance decline was identified in 53/272 (19.5%) of participants on the Mini-Screen Battery. Follow-up NP data were available for 204 participants who had undergone the Mini-Screen. The frequency of sustained NP test performance decline was 7.8% for the Mini-Screen Battery. A lower CD4+ cell count was weakly associated with sustained NP test performance decline. After adjustment for CD4+ cell count, hemoglobin, body mass index, and presence of AIDS, none of the viral burden measures (p24 antigenemia, plasma viremia, quantitative culture) correlated with sustained NP test performance decline. We conclude that these measures of blood HIV viral burden are not markers for NP decline, but that a lower CD4+ cell count is.

Relationship between human immunodeficiency virus-associated dementia and viral load in cerebrospinal fluid and brain

Cerebrospinal fluid (CSF) human immunodeficiency virus (HIV) RNA levels were measured with the Nucleic Acid Sequence-Based Amplification (NASBA) assay to determine the relationship with neurological status; 37 subjects with HIV dementia (HIV-D) were compared with 77 with HIV with minor neurological signs (HIV-MCMD) and 93 neurologically normal HIV-seropositive individuals (HIV-NML). The NASBA assay had a lower limit of detection of 100 copies per milliliter. Mean CSF log HIV RNA levels were significantly higher in those with dementia after adjusting for CD4 count and were correlated with dementia severity. Plasma levels did not distinguish comparably immunosuppressed subjects with or without dementia. CSF and plasma RNA levels were significantly intercorrelated for subjects with CD4 counts <200/mm3 and also correlated inversely with CSF beta2-microglobulin. CSF RNA levels were independent of CSF pleocytosis or antiretroviral exposure. Brain RNA levels were consistently higher than CSF but correlated with CSF values for dementia subjects. The NASBA assay can be used reliably to determine HIV RNA levels in CSF, brain, and plasma samples. CSF HIV RNA may be a surrogate marker for brain infection, based on the observed correlation with brain levels. The association between plasma HIV RNA and CSF levels of HIV and beta2-microglobulin suggests that both viral load and CNS immune activation are important determinants of neurological disease.

Sensory and motor denervation influence epidermal thickness in rat foot glabrous skin

Denervation in man often results in shiny, dry, thin skin. A previous study has shown that the epidermis of glabrous skin in the rat becomes approximately 40% thinner within 1 week following sciatic nerve transection, but which nerve fiber type or types influence epidermal thickness is unknown. In this study, we compared the effects on the epidermis of selective sensory, motor, and sympathetic denervation. Protein gene product 9.5 and calcitonin gene-related peptide immunocytochemical staining were used to determine the extent of denervation of epidermis, dermis, and sweat glands in the footpads. Epidermal thickness of the glabrous plantar skin of the foot was measured. To verify the specificity and reliability of each animal model, the relevant regions of the peripheral nervous system were examined by light or electron microscopy or both. Epidermal thickness decreased significantly following sciatic nerve transection (58% of control, P < 0.05) and dorsal root ganglionectomy (59%; P < 0.05). The thickness also decreased following lumbar ventral rhizotomy (61%; P < 0.01), destruction of lumbar spinal motor neurons (66%; P < 0.05), and botulinum toxin-induced paralysis of the tibialis anterior and gastrocnemius muscles (70%; P < 0.05). A slight decrease followed dorsal rhizotomy (84%; P < 0.01). In contrast, no significant alterations in epidermal thickness were detected following sham operation and sympathectomy. Epidermal thinning was paralleled by reductions in the amounts of transcripts for glyceraldehyde-3-phosphate dehydrogenase and beta-actin. These results suggest that selective loss of both sensory and motor fibers to the hind limb can contribute to reducing epidermal thickness in rat foot glabrous skin.

NeuroAIDS: diagnosis and management

Neurologic disorders are present in 15% to 30% of AIDS patients. The physiologic isolation imposed by the brain and blood-brain barrier have limited characterization of the disorders and assessment of therapy. Only time will tell whether the multidrug antiretroviral regimens that have shown such success in controlling HIV in the systemic compartment will be equally effective in suppressing brain viremia.

Cellular localization of tumor necrosis factor mRNA in neurological tissue from HIV-infected patients by combined reverse transcriptase/polymerase chain reaction in situ hybridization and immunohistochemistry

HIV-induced neurological disease is postulated to be caused by indirect mechanisms. Tumor necrosis factor (TNF)alpha is increased in the brains in human immunodeficiency virus (HIV)-associated dementia and in the spinal cord in vacuolar myelopathy and may play a pathogenetic role in these diseases. Microglia, astrocytes and infiltrating macrophages can be induced to produce TNF alpha and each has been identified as a source of TNF alpha in neurological disease. Reverse transcriptase synthesis of cDNA and polymerase chain reaction amplification of the cDNA was combined with immunocytochemistry to identify the cellular source of TNF alpha in HIV-induced neurological disease. Cells positive for TNF alpha mRNA were more abundant in white matter than gray matter of the brain from demented individuals. TNF alpha mRNA-positive cells in brains and spinal cords were almost exclusively macrophage-lineage cells. Only rare TNF alpha mRNA-positive cells were astrocytes. We conclude that macrophage-lineage cells are the primary source of elevated central nervous system TNF alpha mRNA in providing further evidence that macrophage activation is an important element in the pathogenesis of HIV-associated neurological disease.

Intraepidermal nerve fiber density in patients with painful sensory neuropathy

Despite prominent symptoms of neuropathic pain, patients with small-fiber sensory neuropathies have few objective abnormalities on clinical examination and routine electrodiagnostic studies. We quantified intraepidermal nerve fiber (IENF) density in sections of skin obtained by punch skin biopsy, and found it to be significantly reduced in patients with painful sensory neuropathies compared with age-matched control subjects. In addition, IENF density correlated with clinical estimates of neuropathy severity, as judged by the extent of clinically identifiable sensory abnormalities. IENF density at the calf was lower than that obtained from skin at more proximal sites, indicating the length dependency of small-fiber loss in these neuropathies.

Motor nerve terminal degeneration provides a potential mechanism for rapid recovery in acute motor axonal neuropathy after Campylobacter infection

We investigated the possible mechanisms of paralysis and recovery in a patient with the acute motor axonal neuropathy (AMAN) pattern of the Guillain-Barré syndrome. The AMAN pattern of GBS is characterized clinically by acute paralysis without sensory involvement and electrodiagnostically by low compound motor action potential amplitudes, suggesting axonal damage, without evidence of demyelination. Many AMAN patients have serologic or culture evidence of recent Campylobacter jejuni infection. Pathologically, the most severe cases are characterized by wallerian-like degeneration of motor axons affecting the ventral roots as well as peripheral nerves, but some fatal cases have only minor changes in the roots and peripheral nerves, and some paralyzed patients with the characteristic electrodiagnostic findings of AMAN recover rapidly. The mechanism of paralysis and recovery in such cases has been uncertain. A 64-year-old woman with culture-proven Campylobacter upsaliensis diarrhea developed typical features of AMAN. She improved quickly following plasmapheresis. Her serum contained IgG anti-GM1 antibodies. The lipopolysaccharide of the organism bound peanut agglutinin. This binding was blocked by cholera toxin, suggesting that the organism contained the Gal(beta1-3)GalNAc epitope of GM1 in its lipopolysaccharide. Motor-point biopsy showed denervated neuromuscular junctions and reduced fiber numbers in intramuscular nerves. In contrast, the sural nerve biopsy was normal and skin biopsy showed normal dermal and epidermal innervation. In AMAN the paralysis may reflect degeneration of motor nerve terminals and intramuscular axons. In addition, the anti-GM1 antibodies, which can bind at nodes of Ranvier, might produce failure of conduction. These processes are potentially reversible and likely to underlie the capacity for rapid recovery that characterizes some cases of AMAN.

HIV infection and cognition in intravenous drug users: long-term follow-up

A cohort of 185 HIV-infected injection drug users (IDUs) and seronegative controls was followed with semiannual neuropsychological assessments for up to 4.5 years. Changes in cognitive performance over time were evaluated, and results of seronegative controls were used to adjust for level of education and practice effects. The effects of duration of follow-up, decline in CD4+ count, development of clinical symptoms, antiretroviral use, and diagnosis of AIDS on changes in neuropsychological performance over time were assessed with regression models using the generalized estimating equation approach. Improvement in performance over time, consistent with practice effects, was observed for all measures. The only subtest for which the magnitude of the practice effects was mildly attenuated relative to the seronegative controls was Grooved Pegboard, dominant hand. After adjusting for disease progression and antiretroviral therapy use, none of the time trends for the neuropsychological test scores were significant, suggesting no decline in performance of the seropositive patients relative to the seronegative controls. With development of clinical symptoms, there was a trend in the direction of declining performance. For subjects reporting two or more symptoms but not using antiretroviral therapy, the trend was not significant, whereas having two or more symptoms and using antiretroviral therapy was associated with significantly worse performance on tests of psychomotor speed and memory. With development of AIDS, a significant decline in performance was observed on measures of motor and psychomotor speed as well as memory. There is thus no evidence to suggest that HIV infection in the context of chronic drug and alcohol use significantly alters the frequency or rate of progression of cognitive symptoms. These findings suggest that the natural history of cognitive changes secondary to HIV infection is similar among HIV-infected IDUs and other risk groups such as homosexual/bisexual men.

Comparison of neuropsychological performance between AIDS-free injecting drug users and homosexual men

We performed a cross-sectional comparison of the baseline neuropsychologic performance of 107 injecting drug users and 230 homosexual men participating in two longitudinal studies. Cognitive tests measured attention, memory and psychomotor speed. Using multiple regression modelling, the analysis adjusted for age, IQ score, race, six-month history of alcohol, cocaine, opiates and marijuana use, HIV serostatus and CD4+ lymphocyte count. Injecting drug users showed significantly poorer scores in all neuropsychologic tests in the univariate analysis. However, once adjusted for age, IQ score and race, only Rey Complex Figure tests were significantly worse among injecting drug users. These data indicate that age and IQ score rather than risk group account primarily for the differences in the cognitive performance, regardless of serostatus and CD4+ count.

Myelopathy among Brazilians coinfected with human T-cell lymphotropic virus type I and HIV

OBJECTIVE

To determine whether subjects coinfected with HTLV-I and HIV have a higher frequency of myelopathy than subjects singly infected with HIV.

DESIGN

A prospective, nested case-control study of HTLV-I and HIV coinfected (cases) and HIV singly infected adults (controls) participating in a prospective HIV cohort study at a university hospital outpatient HIV clinic in Rio de Janeiro, Brazil.

MEASUREMENTS

Subjects were evaluated for evidence of myelopathy by a neurologist unaware of their HTLV serologic status. Patients with at least two pyramidal signs, such as paresis, hypertonicity or spasticity, hyperreflexia, clonus, diminished or absent superficial reflexes, or the presence of pathologic reflexes (e.g., Babinski or Hoffmann), were defined as having myelopathy. Myelopathy severity was quantified using the Kurtzke Functional Disability Scale (FDS); patients with FDS scores > or = 4 were considered to have significant myelopathy. Selected patients with myelopathy underwent lumbar puncture for the evaluation of intrathecal synthesis of HTLV-I antibodies.

RESULTS

Of 15 coinfected subjects, 11 (73%) had evidence of myelopathy versus 10 of 62 subjects (16%) with HIV single infection (adjusted odds ratio [OR] = 13.0, p = 0.00002). When only myelopathy patients with FDS scores of > or = 2 or > or = 4 were included, the association between coinfection and the presence of myelopathy remained (OR = 7.3, p = 0.0003 for scores > or = 2; and OR = 8.9 for scores > or = 4, p = 0.04). In addition, a higher proportion of coinfected subjects had peripheral neuropathy (40%) than controls (16%) (OR = 3.5, p = 0.07).

CONCLUSION

Coinfection with HTLV-I was strongly associated with myelopathy among subjects infected with HIV. The relative contribution of HTLV-I versus HIV in the pathogenesis of coinfection-associated myelopathy is not known. Coinfection may also be associated with peripheral neuropathy. Further studies are needed to elucidate the mechanisms of coinfection-associated neurologic conditions.

Immunologic NO synthase: elevation in severe AIDS dementia and induction by HIV-1 gp41

Indirect mechanisms are implicated in the pathogenesis of the dementia associated with human immunodeficiency virus-type 1 (HIV-1) infection. Proinflammatory molecules such as tumor necrosis factor alpha and eicosanoids are elevated in the central nervous system of patients with HIV-1-related dementia. Nitric oxide (NO) is a potential mediator of neuronal injury, because cytokines may activate the immunologic (type II) isoform of NO synthase (iNOS). The levels of iNOS in severe HIV-1-associated dementia coincided with increased expression of the HIV-1 coat protein gp41. Furthermore, gp41 induced iNOS in primary cultures of mixed rat neuronal and glial cells and killed neurons through a NO-dependent mechanism. Thus, gp41-induced NO formation may contribute to the severe cognitive dysfunction associated with HIV-1 infection.

Psychomotor slowing in HIV infection: a predictor of dementia, AIDS and death

The objective of this study was to determine if sustained decline in psychomotor speed tests is associated with an increased risk of progression to dementia, acquired immunodeficiency syndrome (AIDS), or mortality in human immunodeficiency virus (HIV)-1-infected homosexual men in the Baltimore site of the Multicenter AIDS Cohort-Study (MACS). Clinical and neuropsychological data were obtained on 291 HIV+ homosexual men seen semi-annually over a nine year period (1986-1994). A proportional hazards model was used to assess the predictive value of sustained psychomotor slowing (defined as a 2.0 standard deviation (s.d.) decline in performance on either the Symbol Digit Modalities test or Trailmaking test at two consecutive evaluations). Time-dependent co-variates included in the model were sustained psychomotor slowing, number of attended visits, CD4+ lymphocyte count, hemoglobin and antiretroviral medication use. HIV+ participants with and without sustained psychomotor slowing were compared. Outcome variables were the development of dementia, AIDS and death. HIV+ subjects with sustained psychomotor slowing had an increased hazard of dementia (Risk ratio (RR) = 5.0, P = 0.008), AIDS (RR = 2.4, P = 0.02), and death (RR = 2.0, P = 0.04). A similar analysis using sustained cognitive decline in one domain from a more extensive neuropsychological test battery failed to show any predictive value. Sustained decline in psychomotor performance in HIV infection was predictive of dementia, AIDS and death. This brief neuropsychological test battery may be useful for early detection of HIV+ individuals with a poorer prognosis who may benefit from more aggressive treatment to prevent HIV dementia.