Neuropathology and general autopsy findings in AIDS during the last 15 years

Age-Accelerated Increase of White Matter Hyperintensity Volumes Is Exacerbated by Heavy Alcohol Use in People Living With HIV

BACKGROUND

Antiretroviral treatment has enabled people living with HIV infection to have a near-normal life span. With longevity comes opportunities for engaging in risky behavior, including initiation of excessive drinking. Given that both HIV infection and alcohol use disorder (AUD) can disrupt brain white matter integrity, we questioned whether HIV infection, even if successfully treated, or AUD alone results in signs of accelerated white matter aging and whether HIV+AUD comorbidity further accelerates brain aging.

METHODS

Longitudinal magnetic resonance imaging-FLAIR data were acquired over a 15-year period from 179 control individuals, 204 participants with AUD, 70 participants with HIV, and 75 participants with comorbid HIV+AUD. White matter hyperintensity (WMH) volumes were quantified and localized, and their functional relevance was examined with cognitive and motor testing.

RESULTS

The 3 diagnostic groups each had larger WMH volumes than the control group. Although all 4 groups exhibited accelerating volume increases with aging, only the HIV groups showed faster WMH enlargement than control individuals; the comorbid group showed faster acceleration than the HIV-only group. Sex and HIV infection length, but not viral suppression status, moderated acceleration. Correlations emerged between WMH volumes and attention/working memory and executive function scores of the AUD and HIV groups and between WMH volumes and motor skills in the 3 diagnostic groups.

CONCLUSIONS

Even treated HIV can show accelerated aging, possibly from treatment sequelae or legacy effects, and notably from AUD comorbidity. WMH volumes may be especially relevant for tracking HIV and AUD brain health because each condition is associated with liability for hypertensive processes, for which WMHs are considered a marker.

High prevalence of central nervous system cryptococcosis using a fingerprick whole-blood lateral flow assay in individuals with neurological symptoms and advanced HIV disease in a Brazilian emergency department

Timely diagnosis is key in managing central nervous system (CNS) cryptococcosis in people living with HIV/AIDS (PLWHA). There are few data on implementing fingerprick whole-blood cryptococcal antigen (CrAg) lateral flow assay (LFA) as the first test for diagnosing CNS cryptococcosis. We evaluated the prevalence of CNS cryptococcosis and cryptococcal antigenemia using fingerprick whole-blood in a referral emergency department (ED) in São Paulo, Brazil. This was a prospective cohort study of consecutive adult PLWHA with advanced HIV disease and neurological symptoms. Fingerprick whole-blood CrAg LFA was performed at bedside. Seventy-four individuals were enrolled (median age = 40 years; males = 62%). Prevalence of CNS cryptococcosis was 17.6% (13/74); 95% confidence interval (CI), 9.4-30.0%, and prevalence of positive fingerprick whole-blood CrAg LFA was 25.7% (19/74); 95% CI, 15.5-40.1%. Among the six (8.1%) patients with positive fingerprick whole-blood CrAg LFA and negative CSF CrAg LFA, four (5.4%) had isolated asymptomatic cryptococcal antigenemia, one (1.3%) had symptomatic cryptococcal antigenemia, and one (1.3%) had cryptococcemia. Prevalence of CNS cryptococcosis and cryptococcal antigenemia using fingerprick whole-blood CrAg LFA was high. Point-of-care testing was important for diagnosing CNS cryptococcosis in an ED from a middle-income country.

AIDS-related cytomegalovirus encephalitis in the late ART era: A retrospective cohort study at a referral center in Brazil

BACKGROUND

AIDS-related cytomegalovirus (CMV) encephalitis has declined in the combined antiretroviral therapy (ART) era in high-income countries. However, there is scarce information on CMV encephalitis in low- and middle-income countries. The objectives of this study were to identify the prevalence of AIDS-related CMV encephalitis and describe its main features.

METHODS

This was a retrospective cohort study carried out at a referral center in São Paulo, Brazil. We included adult people living with HIV/AIDS (PLWHA), hospitalized in 2019, with a CD4 cell count ≤100/mm³ and quantitation CMV DNA results in plasma. Cases with compatible neurological manifestations and detection of CMV DNA by polymerase chain reaction (PCR) in cerebrospinal fluid samples were defined as CMV encephalitis.

RESULTS

Among 761 PLWHA hospitalized, 248 (32.5%) cases were included in this study. Prevalence of CMV encephalitis was 2.4% (6/248) among all included cases and 7.7% (6/78) among individuals with neurological opportunistic diseases. The six patients with CMV encephalitis were males and had CD4 cell count <50/mm³. Five (83%) cases had CMV encephalitis as AIDS-defining disease and showed CMV DNA detection by PCR >50,000 UI/mL plasma. All six cases received anti-CMV therapy (ganciclovir, n = 4; ganciclovir plus foscarnet, n = 2) and five were discharged to home. CMV encephalitis was not uncommon among hospitalized PLWHA with neurological opportunistic diseases.

CONCLUSIONS

The epidemiological and immunological profile of individuals with CMV encephalitis was similar to that described in the pre-ART era, but in contrast, most cases were treated and discharged from the hospital.

Cerebral toxoplasmosis with neurological co-infection in people living with AIDS/HIV: results of a prospective cohort in São Paulo, Brazil

BACKGROUND

Concomitant neurological diseases in people living with HIV/AIDS (PLWHA) is a challenging subject that has been insufficiently evaluated by prospective clinical studies. The goal of the present study was to identify the clinical characteristics and outcomes of PLWHA with cerebral toxoplasmosis and neurological co-infections.

METHODS

We conducted a prospective observational cohort study at a tertiary teaching center in São Paulo, Brazil, from January to July 2017. Hospitalized PLWHA aged ≥ 18 years with cerebral toxoplasmosis were consecutively enrolled. A standardized neurological examination was performed at admission and weekly until discharge or death. Diagnosis and treatment followed institutional routines; neuroradiology, molecular diagnosis, neurosurgery, and the intensive care unit (ICU) were available. The main outcomes were neurological coinfections and in-hospital death.

RESULTS

We included 44 (4.3%) cases among 1,032 hospitalized patients. The median age was 44 (interquartile range [IQR]: 35-50) years, and 50% (n = 22) of the patients were male. The median CD4+ T lymphocyte count was of 50 (IQR: 15-94) cells/mm³. Multiple lesions on computed tomography were present in 59% of the cases. Neurological coinfections were diagnosed in 20% (n = 9) of the cases, and cytomegalovirus was the most common etiology (encephalitis: n = 3; polyradiculopathy: n = 2). Longer hospital stays (30 versus 62 days; p = 0.021) and a higher rate of ICU admissions (14% versus 44%; p = 0.045) were observed among PLWHA with neurological coinfections in comparison to those without them. The rate of in-hospital mortality was of 13.6% (n = 6) (coinfection group: 33%; no coinfection group: 8.6%; p = 0.054).

CONCLUSION

Neurological c-infections were common among PLWHA with cerebral toxoplasmosis, and cytomegalovirus was the main copathogen. The group of PLWHA with neurological co-infections underwent longer hospital stays and more frequent intensive care unit admissions. Additionally, this group of patients tended to have higher in-hospital mortality rate.

Analysis of Deaths among HIV-Infected Patients Hospitalized in 2009–2018 in Main Centre of Infectious Disease in Region of Lower Silesia in Poland, Detailing Lesions in the Central Nervous System

Background and Objectives: Patients living with HIV (PLWH), especially those diagnosed too late or not receiving treatment with antiretroviral drugs in the stage of advanced immunodeficiency AIDS for various reasons, develop additional opportunistic infections or AIDS-defining diseases that may contribute directly to the death of these patients. Material and Methods: In this work, we focused on disorders of the central nervous system (CNS) by retrospectively analyzing the symptoms, clinical and autopsy diagnoses of patients diagnosed with HIV infection who died in the provincial specialist hospital in the Lower Silesia region in Poland. Results: The autopsy was performed in 27.4% cases. The cause of death was determined to be HIV-related/AIDS-associated in 78% patients. The most common AIDS-defining CNS diseases in our cohort were toxoplasmosis and cryptococcosis. Conslusions: The presented results of the most common causes of changes in the central nervous system among deceased HIV-infected patients are comparable to the results of studies by other scientists cited in the publication.

Unspecified encephalitis in HIV-infected patients: clinical and postmortem evaluation

Background. The search for an aetiology of central nervous system (CNS) lesions In HIV patients can be extremely challenging. Aim. To establish the nature and character of CNS lesion according to the data of pathological examination of deceased HIV-patients who had an antemortem clinical diagnosis of unspecified encephalitis. Materials and methods. We analysed clinical and laboratory data of 225 HIV-patients admitted to the ICU at the Infectious Clinical Hospital №2 (Moscow, 2018). The principal diagnosis was unspecified encephalitis characterized by cerebral oedema. Had died 183 (67.9%) patients. We conducted pathological examination in 43 (23.5%). Results. CNS lesions occurred in 331 patients (58.8% of 563 ICU). The antemortem diagnosis established were as follows: 12.1% toxoplasmosis; 6.6% HIV-encephalitis; 5.1% CNS lymphoma; 3.6% cryptococcal meningoencephalitis; 3.0% cytomegaloviral diseases; 2.1% progressive multifocal leukoencephalopathy. The cause of the pathology remained unidentified in 225 patients (68% with CNS lesions). Majority of patients were ART-naive. Post-mortem verification was conducted in 29 (67.4%) deceased patients, of which HIV-encephalitis 34.5%, toxoplasmosis 10.3%, progressive multifocal leukoencephalopathy 3.4%. The nature of brain damage in the remaining 20.7% cases was not established even after post-mortem investigation. Productive lepto-meningitis 8 (27.6%), indicating a prolonged duration of the inflammatory process. In the brain 48.1% patients with subacute and productive changes, had a pre-hospital time of more than 30 days, in contrast to 11.1% of patients who had acute pathological processes in the CNS (p0.05). Autopsy didnt reveal any inflammatory changes in the brain in 14 (32.6%) patients, though cerebral oedema 93.3%, haemorrhagic syndrome 60% cases. Conclusion. Accurate retrospective identification of the aetiology of CNS lesions combined with assessing in vivo characterisation of the pathological process plays an essential role in subsequent formation of diagnostic approaches in pathologies of the CNS in HIV-patients.

HIV-Related Cerebral Toxoplasmosis Revisited: Current Concepts and Controversies of an Old Disease

Cerebral toxoplasmosis is the most common cause of expansive brain lesions in people living with HIV/AIDS (PLWHA) and continues to cause high morbidity and mortality. The most frequent characteristics are focal subacute neurological deficits and ring-enhancing brain lesions in the basal ganglia, but the spectrum of clinical and neuroradiological manifestations is broad. Early initiation of antitoxoplasma therapy is an important feature of the diagnostic approach of expansive brain lesions in PLWHA. Pyrimethamine-based regimens and trimethoprim-sulfamethoxazole (TMP-SMX) seem to present similar efficacy, but TMP-SMX shows potential practical advantages. The immune reconstitution inflammatory syndrome is uncommon in cerebral toxoplasmosis, and we now have more effective, safe, and friendly combined antiretroviral therapy (cART) options. As a consequence of these 2 variables, the initiation of cART can be performed within 2 weeks after initiation of antitoxoplasma therapy. Herein, we will review historical and current concepts of epidemiology, diagnosis, and treatment of HIV-related cerebral toxoplasmosis.

Endothelins in inflammatory neurological diseases

Endothelins were discovered more than thirty years ago as potent vasoactive compounds. Beyond their well-documented cardiovascular properties, however, the contributions of the endothelin pathway have been demonstrated in several neuroinflammatory processes and the peptides have been reported as clinically relevant biomarkers in neurodegenerative diseases. Several studies report that endothelin-1 significantly contributes to the progression of neuroinflammatory processes, particularly during infections in the central nervous system (CNS), and is associated with a loss of endothelial integrity at the blood brain barrier level. Because of the paucity of clinical trials with endothelin-1 antagonists in several infectious and non-infectious neuroinflammatory diseases, it remains an open question whether the 21 amino acid peptide is a mediator/modulator rather than a biomarker of the progression of neurodegeneration. This review focuses on the potential roles of endothelins in the pathology of neuroinflammatory processes, including infectious diseases of viral, bacterial or parasitic origin in which the synthesis of endothelins or its pharmacology have been investigated from the cell to the bedside in several cases, as well as in non-infectious inflammatory processes such as neurodegenerative disorders like Alzheimers Disease or central nervous system vasculitis.

HIV-1 Tat inhibits EAAT-2 through AEG-1 upregulation in models of HIV-associated neurocognitive disorder

During HIV-associated neurocognitive disorder (HAND), decreasing in excitatory amino acid transporter 2 (EAAT-2) in astrocyte plasma membranes leads to elevated levels of extracellular glutamate and, in turn, neuronal apoptosis. We used immunohistochemistry, western blot, qRT-PCR, and RNA interference to elucidate the molecular mechanisms underlying the decreased EAAT-2 expression during HAND at the tissue and cellular levels. We used simian immunodeficiency virus-human immunodeficiency virus chimeric virus (SHIV)-infected macaques as an in vivo model of HAND. Our results show that EAAT-2 expression was decreased in the cerebral cortex, while AEG-1 expression was increased, and the expression levels of these proteins were negatively correlated. In vitro analyses showed that HIV-1 Tat inhibited EAAT-2 expression by inducing overexpression of AEG-1. More specifically, HIV-1 Tat increased AEG-1 expression via the PI3-K signaling pathway, while increasing EAAT-2 inhibition by YinYan-1 (YY-1) via the NF-κB signaling pathway. These results warrant testing AEG-1 as a potential therapeutic target for treating HAND.

Apoptosis and necroptosis of mouse hippocampal and parenchymal astrocytes, microglia and neurons caused by Angiostrongylus cantonensis infection

BACKGROUND

Angiostrongylus cantonensis has been the only parasite among Angiostrongylidae to cause human central nervous system infection characterized by eosinophilic meningitis or meningoencephalitis. The mechanism of the extensive neurological impairments of hosts caused by A. cantonensis larvae remains unclear. The aim of the present study was to investigate apoptosis, necroptosis and autophagy in the brains of mice infected with A. cantonensis, which will be valuable for better understanding the pathogenesis of angiostrongyliasis cantonensis.

METHODS

Functional and histological neurological impairments of brain tissues from mice infected with A. cantonensis were measured by the Morris water maze test and haematoxylin and eosin (H&E) staining, respectively. The transcriptional and translational levels of apoptosis-, necroptosis- and autophagy-related genes were quantified by quantitative real-time polymerase chain reaction (RT-PCR), and assessed by western blot and immunohistochemistry (IHC) analysis. Apoptotic and necroptotic cells and their distributions in infected brain tissues were analysed by flow cytometry and transmission electron microscopy (TEM).

RESULTS

Inflammatory response in the central nervous system deteriorated as A. cantonensis infection evolved, as characterized by abundant inflammatory cell infiltration underneath the meninges, which peaked at 21 days post-infection (dpi). The learning and memory capacities of the mice were significantly decreased at 14 dpi, indicating prominent impairment of their cognitive functions. Compared with those of the control group, the mRNA levels of caspase-3, -4, -6, and RIP3 and the protein levels of caspase-4, cleaved caspase-3, cleaved caspase-6, RIP3, and pRIP3 were obviously elevated. However, no changes in the mRNA or protein levels of FADD, Beclin-1 or LC3B were evident, indicating that apoptosis and necroptosis, but not autophagy, occurred in the brain tissues of mice infected with A. cantonensis. The quantitative RT-PCR, western blot, IHC, flow cytometry and TEM results further revealed the apoptotic and necroptotic microglia, astrocytes and neurons in the parenchymal and hippocampal regions of infected mice.

CONCLUSIONS

To our knowledge, we showed for the first time that A. cantonensis infection causes the apoptosis and necroptosis of microglia and astrocytes in the parenchymal and hippocampal regions of host brain tissues, further demonstrating the pathogenesis of A. cantonensis infection and providing potential therapeutic targets for the management of angiostrongyliasis.

Role of Monocyte/Macrophages during HIV/SIV Infection in Adult and Pediatric Acquired Immune Deficiency Syndrome

Monocytes/macrophages are a diverse group of cells that act as first responders in innate immunity and then as mediators for adaptive immunity to help clear infections. In performing these functions, however, the macrophage inflammatory responses can also contribute to pathogenesis. Various monocyte and tissue macrophage subsets have been associated with inflammatory disorders and tissue pathogeneses such as occur during HIV infection. Non-human primate research of simian immunodeficiency virus (SIV) has been invaluable in better understanding the pathogenesis of HIV infection. The question of HIV/SIV-infected macrophages serving as a viral reservoir has become significant for achieving a cure. In the rhesus macaque model, SIV-infected macrophages have been shown to promote pathogenesis in several tissues resulting in cardiovascular, metabolic, and neurological diseases. Results from human studies illustrated that alveolar macrophages could be an important HIV reservoir and humanized myeloid-only mice supported productive HIV infection and viral persistence in macrophages during ART treatment. Depletion of CD4+ T cells is considered the primary cause for terminal progression, but it was reported that increasing monocyte turnover was a significantly better predictor in SIV-infected adult macaques. Notably, pediatric cases of HIV/SIV exhibit faster and more severe disease progression than adults, yet neonates have fewer target T cells and generally lack the hallmark CD4+ T cell depletion typical of adult infections. Current data show that the baseline blood monocyte turnover rate was significantly higher in neonatal macaques compared to adults and this remained high with disease progression. In this review, we discuss recent data exploring the contribution of monocytes and macrophages to HIV/SIV infection and progression. Furthermore, we highlight the need to further investigate their role in pediatric cases of infection.

Menin mediates Tat-induced neuronal apoptosis in brain frontal cortex of SIV-infected macaques and in Tat-treated cells

The molecular mechanisms involved in human immunodeficiency virus (HIV)-associated neurocognitive disorder (HAND) remain poorly understood. It has been recently reported that HIV-1 Tat transactivation requires menin, suggesting that menin may be involved in HAND pathogenesis. But the role of menin is not clear. Here, we found that protein level of menin was increased in simian-human immunodeficiency chimeric virus (SHIV)_-SF162.P4 and simian immunodeficiency virus (SIV) _sm543-3-infected rhesus macaques compared with the controls by immunohistochemistry (IHC) and western blot. Menin mainly expressed in the frontal cortex neurons of the brain, more importantly, the number of menin-staining cells was positively correlated with cleaved-caspase-3-positive cells while it was negatively correlated with a neuron-specific nuclear protein NeuN-positive cells, suggesting that expression of menin may induce neuronal apoptosis. Further studies showed that menin level was significantly increased during Tat-induced apoptosis, while downregulation of menin by pll3.7-MEN1-shRNA attenuated the Tat-induced cleavage of caspase-3 and caspase-8 in SY5Y cells and primary neuron cultures. Together, our findings reveal a pro-apoptotic role of menin in the brains of the SIV-infected macaques and the cultured neurons, indicating that targeting menin may be potential to block the HIV-1 Tat induced neuronal damage in HAND.

Reliability of White Matter Microstructural Changes in HIV Infection: Meta-Analysis and Confirmation

BACKGROUND

Diffusion tensor imaging has been widely used to measure HIV effects on white matter microarchitecture. While many authors have reported reduced fractional anisotropy and increased mean diffusivity in HIV, quantitative inconsistencies across studies are numerous.

PURPOSE

Our aim was to evaluate the consistency across studies of HIV effects on DTI measures and then examine the DTI reliability in a longitudinal seropositive cohort.

DATA SOURCES

Published studies and investigators.

STUDY SELECTION

The meta-analysis included 16 cross-sectional studies reporting fractional anisotropy and 12 studies reporting mean diffusivity in the corpus callosum.

DATA ANALYSIS

Random-effects meta-analysis was used to estimate study standardized mean differences and heterogeneity. DTI longitudinal reliability was estimated in seropositive participants studied before and 3 and 6 months after beginning treatment.

DATA SYNTHESIS

Meta-analysis revealed lower fractional anisotropy (standardized mean difference, -0.43; P < .001) and higher mean diffusivity (standardized mean difference, 0.44; P < .003) in seropositive participants. Nevertheless, between-study heterogeneity accounted for 58% and 66% of the observed variance (P < .01). In contrast, the longitudinal cohort fractional anisotropy was higher and mean diffusivity was lower in seropositive participants (both, P < .001), and fractional anisotropy and mean diffusivity measures were very stable during 6 months, with intraclass correlation coefficients all >0.96.

LIMITATIONS

Many studies pooled participants with varying treatments, ages, and disease durations.

CONCLUSIONS

HIV effects on WM microstructure had substantial variations that could result from acquisition, processing, or cohort-selection differences. When acquisition parameters and processing were carefully controlled, the resulting DTI measures did not show high temporal variation. HIV effects on WM microstructure may be age-dependent. The high longitudinal reliability of DTI WM microstructure measures makes them promising disease-activity markers.

Targeting brain cells with glutathione-modulated nanoliposomes: in vitro and in vivo study

Background

The blood–brain barrier prevents many drug moieties from reaching the central nervous system. Therefore, glutathione-modulated nanoliposomes have been engineered to enhance the targeting of flucytosine to the brain.

Methods

Glutathione-modulated nanoliposomes were prepared by thin-film hydration technique and evaluated in the primary brain cells of rats. Lecithin, cholesterol, and span 65 were mixed at 1:1:1 molar ratio. The molar percentage of PEGylated glutathione varied from 0 mol% to 0.75 mol%. The cellular binding and the uptake of the targeted liposomes were both monitored by epifluorescent microscope and flow cytometry techniques. A biodistribution and a pharmacokinetic study of flucytosine and flucytosine-loaded glutathione–modulated liposomes was carried out to evaluate the in vivo brain-targeting efficiency.

Results

The size of glutathione-modulated nanoliposomes was <100 nm and the zeta potential was more than −65 mV. The cumulative release reached 70% for certain formulations. The cellular uptake increased as molar percent of glutathione increased to reach the maximum at 0.75 mol%. The uptake of the targeted liposomes by brain cells of the rats was three times greater than that of the nontargeted liposomes. An in vivo study showed that the relative efficiency was 2.632±0.089 and the concentration efficiency was 1.590±0.049, and also, the drug-targeting index was 3.670±0.824.

Conclusion

Overall, these results revealed that glutathione-PEGylated nanoliposomes enhance the effective delivery of flucytosine to brain and could become a promising new therapeutic option for the treatment of the brain infections.

Brain localization of Kaposi's sarcoma in a patient treated by combination antiretroviral therapy

Background

Central nervous system is a very rare site of Kaposi’s sarcoma in acquired immunodeficiency syndrome. Kaposi’s sarcoma, a neoplasm of endothelial origin, occurs mainly in the skin, but can involve many tissues, especially in patients with a poor immunity. Combination antiretroviral therapy, highly active against human immunodeficiency virus type-1, has caused a dramatic reduction of cutaneous and visceral involvements. No report of central nervous system localization of Kaposi’s sarcoma is described since the introduction of combination antiretroviral therapy in the late 90’s.

Case presentation

A 42 year-old Caucasian man affected by human immunodeficiency virus type-1 infection treated with combination antiretroviral therapy and showing relatively preserved immunity with low viral load presented gingival squamous cell carcinoma and visceral (lungs and lymph nodes) Kaposi’s sarcoma. Chemotherapy and radiotherapy were performed with improvement of both neoplasms. Afterwards, a magnetic resonance imaging showed focal lesions of the brain. Despite new chemotherapy and radiotherapy the patient died. Histology after autopsy revealed brain lesions due to Kaposi’s sarcoma with the detection of Human Herpesvirus 8 on tissue samples.

Conclusions

This is the first report in the combination antiretroviral therapy era of a very rare complication of Kaposi’s sarcoma, such as that of brain localization, in a patient with a relatively good control of human immunodeficiency virus infection. Therefore, Kaposi’s sarcoma should be considered in differential diagnosis with other intracranial mass lesions that can occur in human immunodeficiency virus infected-patients focusing the issue of appropriate treatment for central nervous system involvement.

Expression of substance P, neurokinin-1 receptor and immune markers in the brains of individuals with HIV-associated neuropathology

The tachykinin neuropeptide substance P (SP) has an important signaling role in both the nervous and the immune systems. Two naturally occurring variants of the neurokinin-1 receptor (NK1R) mediate the effects of SP, full-length receptor (NK1R-F) and a truncated form (NK1R-T) that lacks 96 amino acid residues at the C-terminus. We previously reported decreased expression of the NK1R-F in the CNS of HIV-positive individuals in comparison to HIV-negative control subjects. There were no differences in the expression of the NK1R-T in the same groups. In the current study, we quantified the expressions of SP precursor mRNA preprotachykinin (TAC1), NK1R (full and truncated forms), viral load (HIV-gag) and several proinflammatory and immune markers (CD4, CCR5, CXCR4, fractalkine, IL-6, IL-10, CCL2, CCL20 and CD163) in the frontal cortex of autopsied brains from HIV-1-positive individuals with or without HIV-associated neuropathology. The expressions of SP and, to lesser extent, NK1R-F were decreased while the expressions of CXCR4, CCR5 and CCL2 were increased in CNS of individuals with HIV-associated neuropathology. There was no change in HIV loads associated with neuropathology; however, we found a positive correlation between viral loads and the expression of haptoglobin-hemoglobin scavenger receptor CD163. An analysis of CSF from corresponding samples demonstrated an increase in proinflammatory markers (CCL2 MIP-1α and MIP-1β) associated with neuropathology. Although our data confirm the overall inflammatory nature of HIV-associated neuropathology, we observed a decrease in the expression of SP and NK1R-F, which is also associated with other forms of neuroinflammation.

Concurrent occurrence of primary intracranial Epstein-Barr virus-associated leiomyosarcoma and Hodgkin lymphoma in a young adult

Although Epstein-Barr virus (EBV) infection has been known to be associated with a heterogeneous group of malignancies including Hodgkin lymphoma (HL), its association with smooth-muscle tumors (SMTs) has recently been described. Of these SMTs, a primary intracranial EBV-associated leiomyosarcoma (EBV-LMS) is extremely rare, and most of the reported cases were of immunocompromised and/or pediatric patients. A neurologically asymptomatic, previously healthy 27-year-old man was found to have a PET-positive brain lesion during a staging workup for his recently diagnosed HL. Subsequent MRI revealed a 2.6 × 4.0 × 3.3-cm inhomogeneously enhancing tumor with marked surrounding edema in the right anterior frontal lobe. He was serologically HIV negative. He underwent a right frontal lobectomy with gross-total resection of the tumor. Intraoperatively, the tumor had fairly discrete margins and appeared to arise from the anterior falx (that is, it was dural based). Microscopically, the tumor was composed of interlacing fascicles of spindle cells with brisk mitotic activity and multiple foci of necrosis. Immunohistochemically, the tumor cells were positive for caldesmon and smooth-muscle actin and negative for desmin, CD34, CD99, bcl-2, S100 protein, and GFAP. A Ki-67 labeling index was up to 30%. Epstein-Barr virus-encoded RNA in situ hybridization demonstrated strong diffuse positivity with more than 90% of tumor cells staining. Most of the Reed-Sternberg cells in HL were also labeled with Epstein-Barr virus-encoded RNA. This is the first case of a concurrent occurrence of rare intracranial EBV-LMS and HL in a seemingly "immunocompetent" adult patient (immunocompetence determined by routine laboratory data and clinical history). We should be aware of EBV-SMT as a differential diagnosis of dural-based spindle cell neoplasm in this setting given that patients with HL, even at presentation, exhibit a persistent defect in cellular immunity.

Pathology of CNS parasitic infections

Parasitic infections of the central nervous system (CNS) include two broad categories of infectious organisms: single-celled protozoa and multicellular metazoa. The protozoal infections include malaria, American trypanosomiasis, human African trypanosomiasis, toxoplasmosis, amebiasis, microsporidiasis, and leishmaniasis. The metazoal infections are grouped into flatworms, which include trematoda and cestoda, and roundworms or nematoda. Trematoda infections include schistosomiasis and paragonimiasis. Cestoda infections include cysticercosis, coenurosis, hydatidosis, and sparganosis. Nematoda infections include gnathostomiasis, angiostrongyliasis, toxocariasis, strongyloidiasis, filariasis, baylisascariasis, dracunculiasis, micronemiasis, and lagochilascariasis. The most common route of CNS invasion is through the blood. In some cases, the parasite invades the olfactory neuroepithelium in the nasal mucosa and penetrates the brain via the subarachnoid space or reaches the CNS through neural foramina of the skull base around the cranial nerves or vessels. The neuropathological changes vary greatly, depending on the type and size of the parasite, geographical strain variations in parasitic virulence, immune evasion by the parasite, and differences in host immune response. Congestion of the leptomeninges, cerebral edema, hemorrhage, thrombosis, vasculitis, necrosis, calcification, abscesses, meningeal and perivascular polymorphonuclear and mononuclear inflammatory infiltrate, microglial nodules, gliosis, granulomas, and fibrosis can be found affecting isolated or multiple regions of the CNS, or even diffusely spread. Some infections may be present as an expanding mass lesion. The parasites can be identified by conventional histology, immunohistochemistry, in situ hybridization, and PCR.

Infection and upregulation of proinflammatory cytokines in human brain vascular pericytes by human cytomegalovirus

Background

Congenital human cytomegalovirus (HCMV) infections can result in CNS abnormalities in newborn babies including vision loss, mental retardation, motor deficits, seizures, and hearing loss. Brain pericytes play an essential role in the development and function of the blood–brain barrier yet their unique role in HCMV dissemination and neuropathlogy has not been reported.

Methods

Primary human brain vascular pericytes were exposed to a primary clinical isolate of HCMV designated ‘SBCMV’. Infectivity was analyzed by microscopy, immunofluorescence, Western blot, and qRT-PCR. Microarrays were performed to identify proinflammatory cytokines upregulated after SBCMV exposure, and the results validated by real-time quantitative polymerase chain reaction (qPCR) methodology. In situ cytokine expression of pericytes after exposure to HCMV was examined by ELISA and in vivo evidence of HCMV infection of brain pericytes was shown by dual-labeled immunohistochemistry.

Results

HCMV-infected human brain vascular pericytes as evidenced by several markers. Using a clinical isolate of HCMV (SBCMV), microscopy of infected pericytes showed virion production and typical cytomegalic cytopathology. This finding was confirmed by the expression of major immediate early and late virion proteins and by the presence of HCMV mRNA. Brain pericytes were fully permissive for CMV lytic replication after 72 to 96 hours in culture compared to human astrocytes or human brain microvascular endothelial cells (BMVEC). However, temporal transcriptional expression of pp65 virion protein after SBCMV infection was lower than that seen with the HCMV Towne laboratory strain. Using RT-PCR and dual-labeled immunofluorescence, proinflammatory cytokines CXCL8/IL-8, CXCL11/ITAC, and CCL5/Rantes were upregulated in SBCMV-infected cells, as were tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1beta), and interleukin-6 (IL-6). Pericytes exposed to SBCMV elicited higher levels of IL-6 compared to both mock-infected as well as heat-killed virus controls. A 6.6-fold induction of IL-6 and no induction TNF-alpha was observed in SBCMV-infected cell supernatants at 24 hours postinfection. Using archival brain tissue from a patient coinfected with HCMV and HIV, we also found evidence of HCMV infection of pericytes using dual-label immunohistochemistry, as monitored by NG2 proteoglycan staining.

Conclusion

HCMV lytic infection of primary human brain pericytes suggests that pericytes contribute to both virus dissemination in the CNS as well as neuroinflammation.

Atypical progressive multifocal leukoencephalopathy in HIV with a high CD4 count: the use of magnetic resonance imaging plus spectrometry studies

Progressive multifocal leukoencephalopathy (PML) is still a underinvestigated central nervous system infection, often linked to HIV-related immunodeficiency. We present an unusual case report characterized by motor involvement, which occurred as the first AIDS-defining event in the absence of appreciable immunodeficiency in a patient with previously undiagnosed HIV infection, who was also assessed by a functional-metabolic magnetic resonance imaging technique (MRI-spectrometry). A 45-year-old patient had HIV infection detected after the appearance of motor abnormalities, in the absence of other signs or symptoms. No significant immunodeficiency was found (initial CD4+ lymphocyte count of 566 cells/µL), and HIV viral load was 24,000 RNA copies/mL. Combination antiretroviral therapy was started with lamivudine, abacavir and lopinavir/ritonavir, with subsequent addition of efavirenz and enfuvirtide. Elevated cerebrospinal fluid levels of JC virus (JCV) (11,668 copies/µL) and consistent neuroradiological findings at contrast-enhanced computed tomography and MRI scans confirmed a diagnosis of PML. Despite the aggressive therapeutic approach, which achieved undetectable HIV viraemia, a CD4+ count above 700 cells/µL and disappearance of JCV after 20 days, the neurological motor involvement rapidly deteriorated, yet associated cognitive impairment never occurred. Clinical and neuroradiological deterioration occurred, and our patient died five months after the diagnosis due to respiratory failure. Combined MRI-spectrometry studies performed 10 days before death included proton ((1)H) spectrometry, and an MRI study-calculation of water diffusion and anisotropy: through this innovative technique combining morphological and metabolic findings, multiple abnormalities involving the subtentorial white matter were detected (with multiple encephalic trunk and ponto-bulbar lesions), which usually are not part of the PML course.

Neuropathology of AIDS: An Autopsy Review of 284 Cases from Brazil Comparing the Findings Pre- and Post-HAART (Highly Active Antiretroviral Therapy) and Pre- and Postmortem Correlation

A retrospective study of central nervous system (CNS) in 284 autopsy AIDS cases in Brazil (1989–2008) divided into 3 groups: A (without antiretroviral treatment: 163 cases); B (other antiretroviral therapies: 76 cases); C (HAART for 3 months or more: 45 cases). In 165 (58.1%) cases, relevant lesions were found, predominantly infections (54.2%); the most frequent was toxoplasmosis (29.9%) followed by cryptococcosis (15.8%), purulent bacterial infections (3.9%), and HIV encephalitis (2.8%); non-Hodgkin lymphomas occurred in 1.4% and vascular lesions in 1.1%. There was no difference when compared the frequency of lesion among the groups; however, toxoplasmosis was less common while HIV encephalitis was more frequent in group C related to A. CNS lesions remain a frequent cause of death in AIDS; however, the mean survival time was four times greater in group C than in A. In 91 (55.1%) of 165 cases with relevant brain lesions (or 32% of the total 284 cases), there was discordance between pre- and postmortem diagnosis; disagreement type 1 (important disease that if diagnosed in life could change the patient prognosis) occurred in 49 (53.8%) of 91 discordant cases (17.6% of the total 284) indicating the autopsy importance, even with HAART and advanced diagnostics technologies.

The spectrum of clinical and pathological manifestations of AIDS in a consecutive series of 236 autopsied cases in mumbai, India

The HIV epidemic in the Asian subcontinent has a significant impact on India. The AIDS associated pathology has not been well evaluated in a representative study hence very little is known about the spectrum of HIV/AIDS associated diseases in Indian subcontinent. To determine the important postmortem findings in HIV infected individuals in Mumbai, autopsy study was carried out. The patient population included patients with AIDS who died at the tertiary care hospital over a 20 year period from 1988 to 2007. A total of 236 (182; 77% males and 54; 23%) females) patients with AIDS were autopsied. The main risk factor for HIV transmission was heterosexual contact (226 patients; 96%) and 223/236 (94%) patients died of HIV-related diseases. Tuberculosis was the prime cause of death in 149 (63%) patients, followed by bacterial pneumonia 33 (14%), cryptococcosis 18 (8%), toxoplasmosis of brain 15 (6%), pneumocystis jiroveci (PCJ) 1 (0.5%) and Non-Hodgkin's lymphoma 7 (3%) cases. The major underlying pathologies are either preventable or treatable conditions. There is an urgent need for attention towards the diagnosis, issue of therapy, and care of HIV disease in developing countries. Reducing mortality in patients with AIDS from infections must be highest public health policy in India.

Incidence and impact on mortality of severe neurocognitive disorders in persons with and without HIV infection: a Danish nationwide cohort study

OBJECTIVE

The risk of neurocognitive disorders in human immunodeficiency virus (HIV)-infected patients in the era of highly active antiretroviral therapy (HAART) is controversial. We aimed to compare the incidence and impact on mortality of severe neurocognitive disorders (SNCDs) in HIV-infected patients with that of the background population.

METHODS

The method used was a nationwide, population-based cohort study using Danish registries. We calculated incidence rates, incidence rate ratios, mortality rate ratios, and Kaplan-Meier tables to estimate the incidence of and survival after SNCD in HIV-infected patients, compared with a general population control cohort matched by age and sex.

RESULTS

We observed 32 cases of SNCDs among 4452 HIV-infected patients and 120 cases of SNCDs among 62 328 population control subjects. The overall risk of SNCD among HIV-infected patients was 1.0 case per 1000 person-years (PYR), compared with 0.23 cases per 1000 PYR for population control subjects but became 0.35 cases/1000 PYR after 2004, compared with 0.27 cases/1000 PYR in population control subjects. The absence of HAART and a low CD4 lymphocyte count increased the risk of SNCD. The mortality among HIV-infected patients with SNCD was higher than that among population controls with SNCD (median survival, 4.3 years vs 9.7 years [P = .02]).

CONCLUSION

HIV-infected patients have an increased risk of SNCD, but the risk is low and has, in recent years, become comparable to that seen in the background population. In contrast, the mortality remains high among HIV-infected patients diagnosed with SNCD.

HIV-1 infection and cognitive impairment in the cART era: a review

With the introduction of combination antiretroviral therapy AIDS dementia complex or HIV-associated dementia, as it was termed later, largely disappeared in clinical practice. However, in the past few years, patients, long-term infected and treated, including those with systemically well controlled infection, started to complain about milder memory problems and slowness, difficulties in concentration, planning, and multitasking. Neuropsychological studies have confirmed that cognitive impairment occurs in a substantial (15-50%) proportion of patients. Among HIV-1-infected patients cognitive impairment was and is one of the most feared complications of HIV-1 infection. In addition, neurocognitive impairment may affect adherence to treatment and ultimately result in increased morbidity for systemic disease. So what may be going on in the CNS after so many years of apparently controlled HIV-1 infection is an urgent and important challenge in the field of HIV medicine. In this review we summarize the key currently available data. We describe the clinical neurological and neuropsychological findings, the preferred diagnostic approach with new imaging techniques and cerebrospinal fluid analysis. We try to integrate data on pathogenesis and finally discuss possible therapeutic interventions.

Investigation of the significance of Oil Red O-positive macrophage excess in bronchoalveolar lavage fluid during HIV infection

OBJECTIVE

To assess the significance of increased levels of Oil Red O-positive macrophages (ORO-PM) in bronchoalveolar lavage fluids (BALFs) from HIV-positive patients.

METHODS

Cytological data for seventy BALF samples from 66 consecutive HIV-infected patients were analysed according to antiretroviral therapy regimen, presence of Pneumocystis jiroveci infection, blood CD4(+) T cell count, HIV-1 viral load and plasma lipid levels. Non-parametric tests were used to compare the values between groups.

RESULTS

The percentages of ORO-PM were high in this group: 40% [6-80] (median [interquartile range]). They were positively correlated with the BALF total cell count, 21% [5-48.5] for <300 cells/mm(3) and 60% [26.5-80] for >300 cells/mm(3) (P<0.01) but inversely correlated with the percentage of BALF lymphocytes, 50% [20-80] for <15% lymphocytes and 11.5% [2-47] for ≥15% lymphocytes (P<0.01). Antiretroviral therapy with or without protease inhibitors, plasma lipid levels, HIV-1 viral load, blood CD4(+) T cell count or presence of a Pneumocystis jiroveci infection were not correlated with the ORO-PM status.

CONCLUSION

Significantly increased numbers of ORO-PM were correlated with high total cell counts and low lymphocyte counts in BALF, irrespective of disease activity or treatment. Extended work on a larger series of patients needs to be conducted.

Spectrum of intracranial parenchymal lesions in patients with human immunodeficiency virus infection in the Republic of Korea

The incidence of specific intracranial parenchymal lesions of HIV-infected patients varies considerably between countries. In the Republic of Korea, the number of HIV-infected patients is increasing, but little is known regarding the spectrum of intracranial parenchymal lesions in these patients. The aim of the present study was to obtain this information. To identify HIV patients with intracranial parenchymal lesions, the electronic database of radiological reports for 1,167 HIV-infected patients, seen from 1999 to 2008 at the Seoul National University Hospital, were reviewed. Neuroradiologic studies were performed on 165 of these patients, and intracranial parenchymal lesions were detected in 40 (3.4%) of them. Thirty-seven were male, and median age was 41 yr (range, 26-61). At the time of the diagnosis of intracranial parenchymal lesions, median CD4(+) lymphocyte count was 40 cells/microL (range 5-560) and in 33 (82.5%) patients, it was less than 200 cells/microL. Progressive multifocal leukoencephalopathy (12 patients) is the most frequent intracranial parenchymal lesions, followed by intracranial tuberculoma (7 patients), primary central nervous system lymphoma (7 patients), intracranial cryptococcoma (4 patients), Toxoplasma encephalitis (4 patients), and disseminated non-tuberculous mycobacterial infection (3 patients).

[Demyelinating disorders]

Leukoencephalopathies in adults are frequent and exhibit highly variable aetiology, including multiple acquired causes such as inflammatory, vascular or toxic diseases and neoplasias. In contrast leukodystrophies are genetically determined, chronic progressive myelin disorders with a variable pathogenetic background and a great diversity of clinical and paraclinical findings. Some diseases, namely those with an additional inborn error of metabolism, are treatable. Genetic counselling appears to be of major importance for patients and their families. In the light of numerous acquired adulthood leukoencephalopathies a clear delineation of late-onset genetic leukodystrophies is necessary. Clinical symptoms and MRI patterns of some of the major leukodystrophies are reported, including possibilities of biochemical and genetic testing.

[Highly active antiretroviral therapy of neuro-AIDS. Side effects on the nervous system and interactions]

Highly active antiretroviral therapy (HAART) has increased the mean survival time in the AIDS stage to sometimes more than 10 years. Five different groups of antiretroviral medications are known, of which integrase inhibitors and CCR5 antagonists represent the newest and most modern substances. The long AIDS survival time implies that side effects and interactions become relatively more important and must be differentiated from the symptoms of HIV itself. Side effects of HAART concern the central and peripheral nervous system and the muscles. The neurotoxicity of the components in HAART varies considerably and depends on the substance itself. Knowledge of side effects and interactions of HAART with antiepileptics, antidepressants, and analgetics are essential for the treatment of patients with neuro-AIDS.

Minimal conjunctival limbal autograft for total limbal stem cell deficiency

PURPOSE

To report the results of one 60 degrees conjunctival limbal autograft (CLAU) combined with amniotic membrane (AM) transplantation for an eye with total limbal stem cell deficiency (LSCD).

METHODS

One eye of a patient with chronic total LSCD and symblepharon caused by chemical burn was subjected to symblepharon lysis, removal of pannus from corneal surface, AM transplantation to cover the conjunctival and corneal surfaces as a permanent graft, one 60 degrees CLAU to the superior limbal area, and insertion of ProKera as a temporary AM patch to cover the CLAU.

RESULTS

After surgery, corneal epithelialization over the AM was evident adjacent to the CLAU on day 6, progressed to pass the horizontal midline by day 11, and was completed by day 18. During a follow-up of 1 year, the corneal surface remained stable and smooth, and the stroma considerably regained clarity with regression of midstromal vascularization. The best-corrected visual acuity improved from 20/400 to 20/50. The conjunctival inflammation completely resolved, and the fornices were deep.

CONCLUSIONS

One 60 degrees CLAU combined with AM transplantation as both a permanent graft and a temporary patch can restore the entire corneal surface in an eye with total LSCD caused by chemical burn.

Impaired astrocytes and diffuse activation of microglia in the cerebral cortex in simian immunodeficiency virus-infected Macaques without simian immunodeficiency virus encephalitis

Various types of neuronal damage have been reported in acquired immunodeficiency syndrome (AIDS) dementia. We previously demonstrated that inflammation and cortical damage occur independently according to viral tropism in a simian immunodeficiency virus (SIV)-infected macaque model of AIDS dementia. To elucidate the pathogenesis of cortical degeneration, we examined the frontal cortex of SIV-infected macaques and found apoptosis and decreased expression of the excitatory amino acid transporter 2 in astrocytes and diffuse activation of microglia in association with limited neuronal damage. Some activated microglia also expressed excitatory amino acid transporter 2 but not proinflammatory cytokines. No inflammatory changes were seen in the cortex or the white matter, and SIV-infected cells were not detected in or around cortical lesions either by immunohistochemistry or by the polymerase chain reaction detection of SIV genomes of extracted DNA from microdissected tissue samples. These results indicate that an astrocytic abnormality and a compensatory activation of microglia might provide a protective effect against neuronal degeneration in the frontal cortex of SIV-infected macaques without SIV encephalitis.

Expression of proinflammatory cytokines and its relationship with virus infection in the brain of macaques inoculated with macrophage-tropic simian immunodeficiency virus

The pathogenesis of acquired immunodeficiency syndrome dementia complex (ADC) is still poorly understood. Many studies suggest that proinflammatory cytokines such as IL-1beta and TNF-alpha released by microglia/macrophages or astrocytes play a role in CNS injury. A microscopic finding of a microglial nodule with multinucleated giant cells (MNGCs) is a histopathologic hallmark of ADC and named HIV encephalitis. However, in vivo expression of these cytokines in this microenvironment of HIV encephalitis is not yet clarified. One of the main reasons is complexities of brain pathology in patients who have died from terminal AIDS. In this study, we infected two macaques with macrophage-tropic Simian immunodeficiency virus SIV239env/MERT and examined expression of TNF-alpha and IL-1beta in inflammatory lesions with MNGCs and its relation to virus-infected cells using immunohistochemistry. One macaque showed typical inflammatory lesions with MNGCs in the frontal white matter. Small microglial nodules were also detected in the basal ganglia and the spinal cord. SIVenv positive cells were detected mainly in inflammatory lesions, and seemed to be microglia/macrophages and MNGCs based on their morphology. Expression of IL-1beta and TNF-alpha were detected in the inflammatory lesions with MNGCs, and these positive cells were found to be negative for SIVenv by double-labeling immunohistochemistry or immunohistochemistry of serial sections. There were a few TNF-alpha positive cells and almost no IL-1beta positive cells in the area other than inflammatory lesions. Another macaque showed scattered CD3+ cells and CD68+ cells in the perivascular regions of the white matter. SIVenv and TNF-alpha was demonstrated in a few perivascular macrophages. These findings indicate that virus-infected microglia/macrophages do not always express IL-1beta and TNF-alpha, which suggests an indirect role of HIV-1-infected cells in cytokine-mediated pathogenesis of ADC. Our macaque model for human ADC may be useful for better understanding of its pathogenesis.

The Neuropathology of HIV/AIDS

The introduction of Highly Active Anti-retroviral Therapy (HAART) has resulted in significant decreases in morbidity and mortality for subjects infected with HIV. The brain is a major target organ for HIV resulting in significant neuropathological changes in most HIV infected subjects and a wide range of clinical neurological symptoms including HIV associated dementia. In the pre-HAART era HIV associated dementia was a common complication of AIDS. However, since the introduction of HAART the incidence of HIV associated dementia has fallen, but the prevelance has actually risen due to the increasing number of infected subjects and increased life expectancy. HIV associated dementia correlates most closely with neuroinflammation rather than directly with viral load or HIV encephalitis. HIV related clinical and neuropathological disorders are more prevalent in drug abusers than in other risk groups. This review focuses on the shifting pathology observed in HIV infected subjects since the introduction of HAART, discussing the clinical manifestations of these and the influence of confounding factors such as drug abuse and Hepatitis C co-infection.

STAT1 signaling modulates HIV-1-induced inflammatory responses and leukocyte transmigration across the blood-brain barrier

The relationship among neuroinflammation, blood-brain barrier (BBB) dysfunction, and progressive HIV-1 infection as they affect the onset and development of neuroAIDS is incompletely understood. One possible link is signal transducers and activators of transcription (STATs) pathways. These respond to proinflammatory and regulatory factors and could affect neuroinflammatory responses induced from infected cells and disease-affected brain tissue. Our previous works demonstrated that HIV-1 activates pro-inflammatory and interferon-alpha-inducible genes in human brain microvascular endothelial cells (HBMECs) and that these genes are linked to the Janus kinase (JAK)/STAT pathway. We now demonstrate that HIV-1 activates STAT1, induces IL-6 expression, and diminishes expression of claudin-5, ZO-1, and ZO-2 in HBMECs. The STAT1 inhibitor, fludarabine, blocked HIV-1-induced IL-6, diminished HIV-1-induced claudin-5 and ZO-1 down-regulation, and blocked HIV-1- and IL-6-induced monocyte migration across a BBB model. Enhanced expression and activation of STAT1 and decreased claudin-5 were observed in microvessels from autopsied brains of patients with HIV-1-associated dementia. These data support the notion that STAT1 plays an integral role in HIV-1-induced BBB damage and is relevant to viral neuropathogenesis. Inhibition of STAT1 activation could provide a unique therapeutic strategy to attenuate HIV-1-induced BBB compromise and as such improve clinical outcomes.

Neuropathologic contributions to understanding AIDS and the central nervous system

This historical review describes the evolution of the pathogenetic concepts associated with infection by the Human Immunodeficiency Virus (HIV), with emphasis on the pathology of the nervous system. Although the first descriptions of damage to the nervous system in the acquired immunodeficiency syndrome (AIDS) only appeared in 1982, the dramatic diffusion of the epidemic worldwide and the invariably rapidly fatal outcome of the disease, before the introduction of efficient treatment, generated from the beginning an enormous amount of research with rethinking on a number of pathogenetic concepts. Less than 25 years after the first autopsy series of AIDS patients were published and the virus responsible for AIDS was identified, satisfactory definition and classification of a number of neuropathological complications of HIV infection have been established, leading to accurate clinical radiological and biological diagnosis of the main neurological complications of the disease, which remain a major cause of disability and death in AIDS patients. Clinical and experimental studies have provided essential insight into the pathogenesis of CNS lesions and natural history of the disease. The relatively recent introduction of highly active antiretroviral therapy (HAART) in 1995-1996 has dramatically improved the course and prognosis of HIV disease. However, there remain a number of unsolved pathogenetic issues, the most puzzling of which remains the precise mechanism of neuronal damage underlying the specific HIV-related cognitive disorders (HIV dementia). In addition, although HAART has changed the course of neurological complications of HIV infection, new issues have emerged such as the lack of improvement or even paradoxical deterioration of the neurological status in treated patients. Interpretation of these latter data remains largely speculative partly because of the small number of neuropathological studies related to the beneficial consequence of this treatment.

HIV suppression by HAART preserves cognitive function in advanced, immune-reconstituted AIDS patients

INTRODUCTION

HIV can damage neurons leading to cognitive impairment. Epidemiological observations suggest that neuropsychological impairment might progress despite successful HAART therapy, but available prevalence estimates are based on populations that were selected for impairment.

METHODS

Of 433 advanced AIDS patients with documented immune reconstitution (CD4 lymphocyte counts < 50 before and > 100 cells/microl after HAART), 286 had brief assessments of cognition (Trailmaking A/B and Digit Symbol Tests) at least once, no confounding neurological conditions, and available neuropsychological norms with comprehensive demographic corrections. At entry, most were immune reconstituted on HAART (median CD4 cell count 230 cells/microl) and HIV was suppressed (65% < 500; only 14% > 20 000 RNA copies/ml).

RESULTS

Over one quarter (27%) of participants exhibited impairment at their initial neuropsychological assessment, a rate nearly twice that expected in a normal (HIV-uninfected) reference population (14%). These impaired participants did not differ from the unimpaired group with respect to age, sex, education, race, CD4 lymphocyte counts, or HIV-RNA levels. Improved performance on neuropsychological tests was documented over a 2-year period 3-5 years after initiating HAART. This improvement was marginally associated with the continued or improving control of plasma HIV-RNA levels, but not with concurrent levels of immune recovery (CD4 lymphocyte counts).

CONCLUSION

Most advanced AIDS patients responding to HAART for prolonged periods have stable or improving cognition, but remain more likely to be impaired than the general population. During HAART, improving test performance probably reflects both practice effects and continuing neurological recovery after more than 3 years of HAART.

Novel delivery system enhances efficacy of antiretroviral therapy in animal model for HIV-1 encephalitis

Most potent antiretroviral drugs (e.g., HIV-1 protease inhibitors) poorly penetrate the blood-brain barrier. Brain distribution can be limited by the efflux transporter, P-glycoprotein (P-gp). The ability of a novel drug delivery system (block co-polymer P85) that inhibits P-gp, to increase the efficacy of antiretroviral drugs in brain was examined using a severe combined immunodeficiency (SCID) mouse model of HIV-1 encephalitis (HIVE). Severe combined immunodeficiency mice inoculated with HIV-1 infected human monocyte-derived macrophages (MDM) into the basal ganglia were treated with P85, antiretroviral therapy (ART) (zidovudine, lamivudine and nelfinavir (NEL)), or P85 and ART. Mice were killed on days 7 and 14, and brains were evaluated for levels of viral infection. Antiviral effects of NEL, P85, or their combination were evaluated in vitro using HIV-1 infected MDM and showed antiretroviral effects of P85 alone. In SCID mice injected with virus-infected MDM, the combination of ART-P85 and ART alone showed a significant decrease of HIV-1 p24 expressing MDM (25% and 33% of controls, respectively) at day 7 while P85 alone group was not different from control. At day 14, all treatment groups showed a significant decrease in percentage of HIV-1 infected MDM as compared with control. P85 alone and combined ART-P85 groups showed the most significant reduction in percentage of HIV-1 p24 expressing MDM (8% to 22% of control) that were superior to the ART alone group (38% of control). Our findings indicate major antiretroviral effects of P85 and enhanced in vivo efficacy of antiretroviral drugs when combined with P85 in a SCID mouse model of HIVE.

HIV-1 gp120 compromises blood-brain barrier integrity and enhances monocyte migration across blood-brain barrier: implication for viral neuropathogenesis

Human immunodeficiency virus-1 (HIV-1) encephalitis is characterized by brain infiltration of virus-infected monocytes and macrophages. Cellular products and viral proteins secreted by infected cells likely play an important role in blood-brain barrier (BBB) impairment and the development of HIV-1-associated dementia (HAD). We previously demonstrated that HIV-1 envelope glycoprotein gp120 induces toxicity and alters expression of tight junction proteins in human brain microvascular endothelial cells (HBMECs). Here, we delineate the mechanisms of gp120-induced BBB dysfunction. Human brain microvascular endothelial cells expressed HIV-1 co-receptors (CCR5 and CXCR4). Exposure of HBMECs to gp120 derived from macrophage (CCR5) or lymphocyte (CXCR4)-tropic viruses decreased BBB tightness, increased permeability, and enhanced monocyte migration across in vitro BBB models. Blood-brain barrier integrity was restored after gp120 removal. CCR5 antibodies and inhibitors of myosin light chain kinase or protein kinase C (PKC) blocked gp120-enhanced monocyte migration and permeability of BBB in vitro. Exposure of HBMECs to gp120 induced release of intracellular calcium ([Ca(2+)](i)) that was prevented by CCR5 antibody and partially blocked by CXCR4 antagonist. Human immunodeficiency virus-1 gp120 activated three PKC isoforms in HBMECs [PKC-alpha/betaII, PKC(pan)-betaII and PKC-zeta/lambda]. Furthermore, specific PKC inhibitors (acting at the ATP-binding and calcium release site) blocked gp120-induced PKC activation and prevented increase in BBB permeability, supporting the biologic significance of these results. Thus, gp120 can cause dysfunction of BBB via PKC pathways and receptor mediated [Ca(2+)](i) release leading to cytoskeletal alterations and increased monocyte migration.

Brain CD8+ and cytotoxic T lymphocytes are associated with, and may be specific for, human immunodeficiency virus type 1 encephalitis in patients with acquired immunodeficiency syndrome

CD8+ T cells infiltrate brains with human immunodeficiency virus type-1 (HIV-1) encephalitis (HIVE) and related animal models; their perineuronal localization suggests cytotoxic T cell (CTL)-mediated neuronal killing. Because CTLs have not been identified in acquired immunodeficiency syndrome (AIDS) brains, the authors identified their cytotoxic granules in autopsy AIDS brains with HIVE and without HIVE (HIVnE) plus controls (7 to 13 cases/group) and determined gene expression profiles of CTL-associated genes in a separate series of cases. CD3+ and CD8+ T cells were significantly increased (P < .01) in perivascular spaces and inflammatory nodules in HIVE but were rare or absent in brain parenchyma in HIVnE and control brains. Eight HIVE brains contained granzyme B+ T cells and five contained perforin+ T cells. Their T-cell origin was confirmed by colocalization of CD8 and granzyme B in the same cell and the absence of CD56+ natural killer cells. The CTLs directly contacted with neurons, as the authors showed previously for CD3+ and CD8+ T cells. CTLs were rare or absent in HIV nonencephalitis (HIVnE) and controls. Granzyme B and H precursor gene expression was up-regulated and interleukin (IL)-12A precursor, a maturation factor for natural killer cells and CTLs, was down-regulated in HIVE versus HIVnE brain. This study demonstrates, for the first time, CTLs in HIVE and shows that parenchymal T cells and CTLs are sensitive biomarkers for HIVE. Consequently, CD8+ T cells and CTLs could mediate brain injury in HIVE and may represent an important biomarker for productive brain infection by HIV-1.

Increased expression of interferon-inducible genes in macaque lung tissues during simian immunodeficiency virus infection

Pulmonary infections and dysfunction are frequent outcomes during the development of immunodeficiency associated with human immunodeficiency virus type 1 (HIV-1) infection, and obtaining a better understanding of the immunologic changes that occur in lungs following HIV-1 infection will provide a foundation for the development of further intervention strategies. We sought here to identify changes in the pulmonary immune environment that arise during simian immunodeficiency virus (SIV) infection of rhesus macaques, which serves as an excellent model system for HIV-1 infection and disease. To examine the gene expression profiles of macaque lung tissues following infection with the pathogenic SIV/DeltaB670 isolate, we performed cDNA microarray hybridizations with lung total RNAs using two commercially available cDNA arrays and a custom-fabricated, immunologically focused macaque cDNA microarray. In situ hybridization and real-time RT-PCR were performed to provide additional analyses of gene expression. Among the genes exhibiting the highest level of induction in lung tissues were the IFN-gamma-inducible chemokines, CXCL10/IP-10 and CXCL9/Mig. In situ hybridization and real-time RT-PCR strongly supported these findings. Correlation analyses revealed that the levels of expression of IFN-gamma, CXCL9/Mig, and CXCL10/IP-10 mRNAs were all strongly positively correlated, and that CXCL10/IP-10 mRNA and Pneumocystis carinii rRNA were positively correlated. Taken together, these findings demonstrate that inflammatory chemokines are among the most differentially expressed mRNAs in macaque lung tissues during systemic SIV infection of rhesus macaques, and provide insight into the complicated events occurring in the lung tissues during HIV-1 infection in humans.

Changing patterns in the neuropathogenesis of HIV during the HAART era

Rapid progress in the development of highly active antiretroviral therapy has changed the observed patterns in HIV encephalitis and AIDS-related CNS opportunistic infections. Early in the AIDS epidemic, autopsy studies pointed to a high prevalence of these conditions. With the advent of nucleoside reverse transcriptase inhibitors, the prevalence at autopsy of opportunistic infections, such as toxoplasmosis and progressive multifocal leukoencephalopathy, declined while that of HIV encephalitis increased. After the introduction of protease inhibitors, a decline in both HIV encephalitis and CNS opportunistic infections was observed. However, with the increasing resistance of HIV strains to antiretrovirals, there has been a resurgence in the frequency of HIV encephalitis and HIV leukoencephalopathy. HIV leukoencephalopathy in AIDS patients failing highly active antiretroviral therapy is characterized by massive infiltration of HIV infected monocytes/macrophages into the brain and extensive white matter destruction. This condition may be attributable to interactions of anti-retrovirals with cerebrovascular endothelium, astroglial cells and white matter of the brain. These interactions may lead to cerebral ischemia, increased blood-brain barrier permeability and demyelination. Potential mechanisms of such interactions include alterations in host cell signaling that may result in trophic factor dysregulation and mitochondrial injury. We conclude that despite the initial success of combined anti-retroviral therapy, more severe forms of HIV encephalitis appear to be emerging as the epidemic matures. Factors that may contribute to this worsening include the prolonged survival of HIV-infected patients, thereby prolonging the brain's exposure to HIV virions and proteins, the use of increasingly toxic combinations of poorly penetrating drugs in highly antiretroviral-experienced AIDS patients, and selection of more virulent HIV strains with higher replication rates and greater virulence in neural tissues.

Neurological disease in HIV-infected patients in the era of highly active antiretroviral treatment: a Brazilian experience

To study characteristics of neurological disorders in HIV/AIDS patients and their relationship to highly active antiretroviral treatment, a cross-sectional study was conducted in an infectious disease public hospital in Belo Horizonte, Brazil, between February 1999 and March 2000. Of the 417 patients enrolled, neurological disease was observed in 194 (46.5%) and a new AIDS-defining neurological event developed in 23.7% of individuals. Toxoplasmosis (42.3%), cryptococcosis meningitis (12.9%) and tuberculosis (10.8%) were the most common causes of neurological complications. The majority (79.3%) of patients were on highly active antiretroviral treatment and these individuals using HAART showed higher CD4 cell counts (p = 0.014) and presented stable neurological disease (p= 0.0001), although no difference was found with respect to the profile of neurological complications. The neurological diseases continue to be a frequent complication of HIV/AIDS and infections are still its main causes in Brazil, even in the highly active antiretroviral treatment era.