Neuroimaging of HIV-associated neurocognitive disorders

A significant increase in the incidence of cognitive impairment in HIV/AIDS patients has been continuously observed. Consequently, three classification categories of cognitive impairment have been proposed: asymptomatic neurocognitive impairment (ANI) and mild neurocognitive disorder (MND), that correspond to the mild and intermediate forms, and HIV-associated dementia (HAD) for the most severe cases. HIV-associated neurocognitive disorders (HAND) is a broad term that encompasses these three categories. Moreover, the application of neuroimaging methods has led to a major breakthrough in understanding of the neurological changes in HIV, providing greater reliability in the exclusion of associated diseases and allowing earlier diagnosis. Therefore, abnormalities and/or specific neuroimaging elements may soon be incorporated into the HAND classification criteria, which will be of great value in the management of these diseases, including in the optimization of high CNS penetration antiretroviral regimens.

Interactive effects of cocaine on HIV infection: implication in HIV-associated neurocognitive disorder and neuroAIDS

Substantial epidemiological studies suggest that not only, being one of the reasons for the transmission of the human immunodeficiency virus (HIV), but drug abuse also serves its role in determining the disease progression and severity among the HIV infected population. This article focuses on the drug cocaine, and its role in facilitating entry of HIV into the CNS and mechanisms of development of neurologic complications in infected individuals. Cocaine is a powerfully addictive central nervous system stimulating drug, which increases the level of neurotransmitter dopamine (DA) in the brain, by blocking the dopamine transporters (DAT) which is critical for DA homeostasis and neurocognitive function. Tat protein of HIV acts as an allosteric modulator of DAT, where as cocaine acts as reuptake inhibitor. When macrophages in the CNS are exposed to DA, their number increases. These macrophages release inflammatory mediators and neurotoxins, causing chronic neuroinflammation. Cocaine abuse during HIV infection enhances the production of platelet monocyte complexes (PMCs), which may cross transendothelial barrier, and result in HIV-associated neurocognitive disorder (HAND). HAND is characterized by neuroinflammation, including astrogliosis, multinucleated giant cells, and neuronal apoptosis that is linked to progressive virus infection and immune deterioration. Cocaine and viral proteins are capable of eliciting signaling transduction pathways in neurons, involving in mitochondrial membrane potential loss, oxidative stress, activation of JNK, p38, and ERK/MAPK pathways, and results in downstream activation of NF-κB that leads to HAND. Tat-induced inflammation provokes permeability of the blood brain barrier (BBB) in the platelet dependent manner, which can potentially be the reason for progression to HAND during HIV infection. A better understanding on the role of cocaine in HIV infection can give a clue in developing novel therapeutic strategies against HIV-1 infection in cocaine using HIV infected population.

HIV-1 Tat and cocaine mediated synaptopathy in cortical and midbrain neurons is prevented by the isoflavone Equol

Illicit drugs, such as cocaine, are known to increase the likelihood and severity of HIV-1 associated neurocognitive disorders (HAND). In the current studies synaptic integrity was assessed following exposure to low concentrations of the HIV-1 viral protein Tat 1-86B, with or without cocaine, by quantifying filamentous actin (F-actin) rich structures (i.e., puncta and dendritic spines) on neuronal dendrites in vitro. In addition, the synapse-protective effects of either R-Equol (RE) or S-Equol (SE; derivatives of the soy isoflavone, daidzein) were determined. Individually, neither low concentrations of HIV-1 Tat (10 nM) nor low concentrations of cocaine (1.6 μM) had any significant effect on F-actin puncta number; however, the same low concentrations of HIV-1 Tat + cocaine in combination significantly reduced dendritic synapses. This synaptic reduction was prevented by pre-treatment with either RE or SE, in an estrogen receptor beta dependent manner. In sum, targeted therapeutic intervention with SE may prevent HIV-1 + drug abuse synaptopathy, and thereby potentially influence the development of HAND.

HIV-infected microglia mediate cathepsin B-induced neurotoxicity

HIV-1-infected mononuclear phagocytes release soluble factors that affect the homeostasis in tissue. HIV-1 can prompt metabolic encephalopathy with the addition of neuronal dysfunction and apoptosis. Recently, we reported that HIV-1 enhances the expression and secretion of bioactive cathepsin B in monocyte-derived macrophages, ultimately contributing to neuronal apoptosis. In this research, we asked if microglia respond to HIV infection similarly by modifying the expression, secretion, and neurotoxic potential of cathepsin B and determined the in vivo relevance of these findings. HIV-1ADA-infected human primary microglia and CHME-5 microglia cell line were assessed for expression and activity of cathepsin B, its inhibitors, cystatins B and C, and the neurotoxicity associated with these changes. Human primary neurons were exposed to supernatants from HIV-infected and uninfected microglia in the presence of cathepsin B inhibitors and apoptosis was assessed by TUNEL. Microglial expression of cathepsin B was validated in brain tissue from HIV encephalitis (HIVE) patients. HIV-infected microglia secreted significantly greater levels of cathepsin B, cystatin B, and cystatin C compared to uninfected cells. Increased apoptosis was observed in neurons exposed to supernatants from HIV-1 infected microglia at day 12 post-infection. The cathepsin B inhibitor CA-074 and cathepsin B antibody prevented neuronal apoptosis. Increased microglia-derived cathepsin B, cystatin B, and cystatin C and caspase-3+ neurons were detected in HIVE brains compared to controls. Our results suggest that HIV-1-induced cathepsin B production in microglia contributes to neuronal apoptosis and may be an important factor in neuronal death associated with HIVE.

Cognitive impairment in patients with AIDS - prevalence and severity

The advent of highly active antiretroviral therapy has prolonged the life expectancy of HIV patients and decreased the number of adults who progress to AIDS and HIV-associated dementia. However, neurocognitive deficits remain a pronounced consequence of HIV/AIDS. HIV-1 infection targets the central nervous system in subcortical brain areas and leads to high rates of delirium, depression, opportunistic central nervous system infections, and dementia. Long-term HIV replication in the brain occurs in astrocytes and microglia, allowing the virus to hide from antiviral medication and later compromise neuronal function. The associated cognitive disturbance is linked to both viral activity and inflammatory and other mediators from these immune cells that lead to the damage associated with HIV-associated neurocognitive disorders, a general term given for these disturbances. We review the severity and prevalence of the neuropsychiatric complications of HIV including delirium, neurobehavioral impairments (depression), minor cognitive-motor dysfunction, and HIV-associated dementia.

Role of Sigma Receptor in Cocaine-Mediated Induction of Glial Fibrillary Acidic Protein: Implications for HAND

Cocaine abuse has been shown to accelerate the progression of human immunodeficiency virus (HIV)-1-associated neurological disorders (HANDs) partially through increasing neuroinflammatory response mediated by activated astrocytes; however, the detailed molecular mechanism of cocaine-mediated astrocyte activation is unclear. In the current study, we demonstrated increased astrogliosis in the cortical regions of brains from HIV(+) cocaine abusers compared with the HIV(+) group without cocaine abuse. We next sought to explore whether cocaine exposure could result in increased expression of glial fibrillary acidic protein (GFAP), a filament protein critical for astrocyte activation. Exposure of cocaine to astrocytes resulted in rapid translocation of sigma receptor to the plasma membrane with subsequent activation of downstream signaling pathways. Using a pharmacological approach, we provide evidence that cocaine-mediated upregulation of GFAP expression involved activation of mitogen-activated protein kinase (MAPK) signaling with subsequent downstream activation of the early growth response gene 1 (Egr-1). Egr-1 activation, in turn, caused transcriptional regulation of GFAP. Corroboration of these findings in vivo demonstrated increased expression of GFAP in the cortical region of mice treated with cocaine compared with the saline injected controls. A thorough understanding of how cocaine mediates astrogliosis could have implications for the development of therapeutic interventions aimed at HIV-infected cocaine abusers.

Variation in rheumatoid hand and wrist surgery among medicare beneficiaries: a population-based cohort study

OBJECTIVE

To examine the rate and variation in rheumatoid arthritis (RA)-related hand and wrist surgery among Medicare (elderly) beneficiaries in the United States, and to identify the patient and provider factors that influence surgical rates.

METHODS

Using the 2006-2010 100% Medicare claims data of beneficiaries with RA diagnosis, we examined rates of rheumatoid hand and wrist arthroplasty, arthrodesis, and hand tendon reconstruction in the United States. We used multivariate logistic regression models to examine variation in receipt of surgery by patient and regional characteristics (density of providers, intensity of use of biologic disease-modifying antirheumatic drugs).

RESULTS

Between 2006 and 2010, the annual rate of RA-related hand and wrist arthroplasty or arthrodesis was 23.1 per 10,000 patients, and the annual rate of hand tendon reconstruction was 4.2 per 10,000 patients. The rates of surgery varied 9-fold across hospital referral regions in the United States. Younger patient age, female sex, white race, higher socioeconomic status (SES), and rural residence were associated with a higher likelihood of undergoing arthroplasty and arthrodesis. We observed a significant decline in rate of arthroplasty and arthrodesis with increasing density of rheumatologists. Tendon reconstruction was not influenced by provider factors, but was correlated with age, race, SES, and rural status of the patients.

CONCLUSION

Surgical reconstruction of rheumatoid hand deformities varies widely across the United States, driven by both regional availability of subspecialty care in rheumatology and individual patient factors.

Longitudinal Analysis of Cerebrospinal Fluid and Plasma HIV-1 Envelope Sequences Isolated From a Single Donor with HIV Asymptomatic Neurocognitive Impairment

OBJECTIVE

Combined antiretroviral treatment (cART) has changed the clinical presentation of HIV-associated neurocognitive disorders (HAND) to that of the milder forms of the disease. Asymptomatic neurocognitive impairment (ANI) is now more prevalent and is associated with increased morbidity and mortality risk in HIV-1-infected people. HIV-1 envelope (env) genetic heterogeneity has been detected within the central nervous system (CNS) of individuals with ANI. Changes within env determine co-receptor use, cellular tropism, and neuropathogenesis. We hypothesize that compartmental changes are associated with HIV-1 env C2V4 during ANI and sought to analyze paired HIV-1 env sequences from plasma and cerebrospinal fluid (CSF) of a female subject undergoing long-term cART.

METHODS

Paired plasma and CSF samples were collected at 12-month intervals and HIV-1 env C2V4 was cloned and sequenced.

RESULTS

Phylogenetic analysis of paired samples consistently showed genetic variants unique to the CSF. Phenotypic prediction showed CCR5 (R5) variants for all CSF-derived sequences and showed minor X4 variants (or dual-tropic) in the plasma at later time points. Viral compartmentalization was evident throughout the study, suggesting that the occurrence of distinctive env strains may contribute to the neuropathogenesis of HAND.

CONCLUSIONS

Our study provides new insights about the genetic characteristics within the C2V4 of HIV-1 env that persist after long-term cART and during the course of persistent ANI.

HIV gp120 sequence variability associated with HAND in Hispanic Women

OBJECTIVE

HIV-1 variants with different tropisms are associated with various neuropathologies. This study intends to determine if this correlation is determined by unique viral env sequences. We hypothesize that HIV-1 envelope gene sequence changes are associated with cognition status.

METHODS

Viral RNA was extracted from peripheral blood mononuclear cells (PBMCs) co-cultures derived from HIV-1 infected Hispanic women that had been characterized for HIV associated neurocognitive disorders (HAND).

RESULTS

Analyses of the C2V4 region of HIV gp120 demonstrated that increased sequence diversity correlates with cognition status as sequences derived from subjects with normal cognition exhibited less diversity than sequences derived from subjects with cognitive impairment. In addition, differences in V3 and V4 loop charges were also noted as well as differences in the N-glycosylation of the V4 region.

CONCLUSIONS

Our data suggest that the genetic signature within the C2V4 region may contribute to the pathogenesis of HAND. HIV env sequence characteristics for the isolates grouped in milder forms of HAND can provide insightful information of prognostic value to assess neurocognitive status in HIV⁺ subjects, particularly during the era of highly prevalent milder forms of HAND.

The Montreal Cognitive Assessment: A Pilot Study of a Brief Screening Tool for Mild and Moderate Cognitive Impairment in HIV-Positive Veterans

HIV-associated neurocognitive disorders (HANDs) are common, often go undetected, and can impact treatment outcomes. There is limited evidence on how to perform routine cognitive screening in HIV clinical settings. To address this, 44 HIV-positive males were recruited from a Veteran Affairs Infectious Disease clinic and completed the Montreal Cognitive Assessment (MoCA), International HIV Dementia Scale (IHDS), and Depression Anxiety and Stress Scale-21. In all, 50% scored below the MoCA cutoff and 36% scored below the IHDS cutoff. Current CD4 was the strongest predictor of an abnormal MoCA score (P = .007, 95% confidence interval [CI]: 0.987-0.998) and elevated depression was the second strongest predictor (P = .008, CI: 1.043-1.326). Combination antiviral therapy use and age were not significant predictors in this model. The MoCA appeared to be a reasonable screening tool to detect cognitive impairment in HIV-positive patients, and although it is not sufficient to diagnose HAND, it has the potential to provide meaningful clinical data.

Ischemic digital ulcers affect hand disability and pain in systemic sclerosis

OBJECTIVE

Ischemic digital ulcers (DU) are frequent and severe complications of systemic sclerosis (SSc). The purpose of our study was to assess the effect of DU on hand disability and pain in patients with SSc.

METHODS

The Evaluation of the Impact of Recurrent Ischemic DU on Hand Disability in Patients with SSc (ECLIPSE) is a prospective, multicenter, noninterventional study with a 2-year followup. Patients with SSc who experienced at least 1 DU in the previous year and received bosentan therapy were included between October 2009 and March 2011. This cohort is described at the time of inclusion.

RESULTS

There were 190 patients (132 females) from 53 centers. Mean age ± SD was 43 ± 15 years at SSc diagnosis and 53 ± 15 years at inclusion. In 105 patients (56.2%), DU were the first non-Raynaud symptoms of SSc. The mean time interval between the occurrence of Raynaud phenomenon and the first DU episode was 6.6 ± 9.1 years. The mean numbers of active DU and fingers affected per patient for both hands were 2.3 ± 1.8 and 2.2 ± 1.6, respectively. Presence of active DU at inclusion was significantly associated with pain and impaired hand function: Visual Analog Scale for pain (0 to 10) was 6.2 ± 2.6 versus 2.5 ± 2.4 (p < 0.0001) and Cochin Hand Function Scale for hand disability (0 to 90) was 38 ± 20 versus 25 ± 19 (p < 0.0001), respectively.

CONCLUSION

DU represent a major sign of SSc, often affecting multiple fingers and both hands. They are significantly associated with pain and hand disability.

HIV-associated neurocognitive disorders

Currently, neuropsychological impairment among HIV+ patients on antiretroviral therapy leads to a reduction in the quality of life and it is an important challenge due to the high prevalence of HIV-associated neurocognitive disorders and its concomitant consequences in relation to morbidity and mortality- including those HIV+ patients with adequate immunological and virological status. The fact that the virus is established in CNS in the early stages and its persistence within the CNS can help us to understand HIV-related brain injury even when highly active antiretroviral therapy is effective. The rising interest in HIV associated neurocognitive disorders has let to development new diagnostic tools, improvement of the neuropsychological tests, and the use of new biomarkers and new neuroimaging techniques that can help the diagnosis. Standardization and homogenization of neurocognitive tests as well as normalizing and simplification of easily accessible tools that can identify patients with increased risk of cognitive impairment represent an urgent requirement. Future efforts should also focus on diagnostic keys and searching for useful strategies in order to decrease HIV neurotoxicity within the CNS.

Report from the OMERACT Hand Osteoarthritis Special Interest Group: advances and future research priorities

Osteoarthritis (OA) is one of the most common musculoskeletal disorders, frequently affecting the hands. In the last decade there has been increased awareness concerning this disorder because of its clinical burden. Unfortunately, only limited treatments for symptom alleviation are available, and no effective treatment for disease modification exists. The lack of treatment is due not only to a lack of understanding of the disease process, but also to poor outcome measures to assess the condition. The OMERACT Hand OA Special Interest Group (SIG) has started to develop a core set of outcome measures for hand OA clinical trials, observational studies, and clinical record keeping. At OMERACT 11, results from a Delphi exercise were presented, and a preliminary set of core domains was discussed. The group attempted to adopt the new OMERACT Filter 2.0 in the process, and literature overviews of conventional radiographs, ultrasonography, and magnetic resonance imaging as outcome measures in hand OA were presented. Discussions that followed highlighted further suggestions for core domains, the heterogeneity of hand OA, and future research priorities.

Aging and HIV/AIDS: neurocognitive implications for older HIV-positive Latina/o adults

In recent years, HIV/AIDS populations have become older and increasingly more ethnically diverse. Concurrently, the prevalence of HIV-related neurocognitive (NC) impairment remains high. This study examined the effects of age and ethnicity on NC function in HIV-positive adults. The sample (N = 126; 84 Latina/o and 42 Non-Hispanic White) completed a comprehensive NC battery. Global NC and domain average demographically-corrected t-scores were generated. There were no significant differences between Younger (<50 years) Latina/os and non-Hispanic Whites on Global NC function or NC domains (all p's >.10), with generally small effect sizes. Older Latina/os (≥50 years) were significantly more impaired than Older Non-Hispanic Whites on processing speed and learning, with trends in Global NC function and memory. Further, effect sizes fell within the medium to large range (Cohen's d's = .49-1.15). This study suggests that older Latina/os are at potentially greater risk for NC impairment, particularly in processing speed and learning, when compared to similarly-aged non-Hispanic whites.

Human immunodeficiency virus-associated dementia: a link between accumulation of viral proteins and neuronal degeneration

In the late stage of human immunodeficiency virus-1 (HIV) infection, a subset of individuals develops HIV associated neurocognitive disorders (HAND), which in its severe form, is characterized by motor and cognitive dysfunction. Dendritic pruning, synaptic abnormalities and neuronal apoptosis are observed in these patients. There are numerous advances in our understanding of HIV interactions with cells of the central nervous system. However, the underlying causes of neurological symptoms and pathological alterations observed in HIV positive subjects are poorly understood. Moreover, little is still known about the molecular mechanisms by which HIV induces synaptic dysfunction and degeneration. HAND resembles other common neurological diseases such as Alzheimer's and Huntington's diseases. These neurodegenerative disorders are characterized by accumulation of toxic proteins such as tau and huntingtin, respectively, which promote axonal degeneration by impairing axonal transport. Axonal degeneration precedes neuronal death. Therefore, a better understanding of the mechanisms whereby HIV triggers axonal degeneration has potential implications for developing therapeutic compounds to prevent synaptic failure in HAND. This article highlights and reviews evidence showing that neuronal accumulation of viral proteins promotes axonal damage.

A role for spermine oxidase as a mediator of reactive oxygen species production in HIV-Tat-induced neuronal toxicity

Chronic oxidative stress, which occurs in brain tissues of HIV-infected patients, is involved in the pathogenesis of HIV-associated dementia. Oxidative stress can be induced by HIV-1-secreted proteins, either directly or indirectly through the release of cytotoxic factors. In particular, HIV-1 Tat is able to induce neuronal death by interacting with and activating the polyamine-sensitive subtype of the NMDA receptor (NMDAR). Here, we focused on the role of polyamine catabolism in Tat-induced oxidative stress in human neuroblastoma (SH-SY5Y) cells. First, Tat was found to induce reactive oxygen species production and to affect cell viability in SH-SY5Y cells, these effects being mediated by spermine oxidase (SMO). Second, Tat was observed to increase SMO activity as well as decreasing the intracellular spermine levels. Third, Tat-induced SMO activation was completely prevented by the NMDAR antagonist MK-801, clearly indicating an involvement of NMDAR stimulation. Finally, pretreatment of cells with N-acetylcysteine, a scavenger of H₂O₂, and with MK-801 was able to completely inhibit reactive oxygen species formation and to restore cell viability. Altogether, these data strongly suggest a role for polyamine catabolism-derived H₂O₂ in neurotoxicity as elicited by Tat-stimulated NMDAR.

A Case of Reversible Neuropsychiatry Symptoms in HIV due to Toxic Leukoencephalopathy

Mothball ingestion has been previously cited to induce toxic-leukoencephalopathy, secondary to the destructive effects of paradichlorobenzene on central nervous system white matter. This case presents a 37-year-old woman who experienced a neuropsychiatric syndrome consistent with paradichlorobenzene-induced toxic leukoencephalopathy after two decades of mothball abuse. Her clinical presentation was insidious, involving fluctuating cognitive decline, depression, and psychosis. This was further complicated by an human immunodeficiency virus infection and concomitant cocaine abuse. Ultimately, her clinical findings were attributed to a reversible toxic-leukoencephalopathy from mothball ingestion, and her magnetic resonance imaging findings were consistent with symmetric leukoencephalopathy and atrophy. Though leukoencephalopathy in human immunodeficiency virus has numerous potential etiologies, a patient with a history of substance abuse warrants consideration of toxin-induced leukoencephalopathy, and further inquiry regarding abuse of other substances is appropriate.

Synaptodendritic recovery following HIV Tat exposure: neurorestoration by phytoestrogens

HIV-1 infects the brain and, despite antiretroviral therapy, many infected individuals suffer from HIV-1-associated neurocognitive disorders (HAND). HAND is associated with dendritic simplification and synaptic loss. Prevention of synaptodendritic damage may ameliorate or forestall neurocognitive decline in latent HIV-1 infections. The HIV-1 transactivating protein (Tat) is produced during viral latency in the brain and may cause synaptodendritic damage. This study examined the integrity of the dendritic network after exposure to HIV-1 Tat by labeling filamentous actin (F-actin)-rich structures (puncta) in primary neuronal cultures. After 24 h of treatment, HIV-1 Tat was associated with the dendritic arbor and produced a significant reduction of F-actin-labeled dendritic puncta as well as loss of dendrites. Pre-treatment with either of two plant-derived phytoestrogen compounds (daidzein and liquiritigenin), significantly reduced synaptodendritic damage following HIV-1 Tat treatment. In addition, 6 days after HIV-1 Tat treatment, treatment with either daidzein, or liquiritigenin enhanced recovery, via the estrogen receptor, from HIV-1 Tat-induced synaptodendritic damage. These results suggest that either liquiritigenin or daidzein may not only attenuate acute synaptodendritic injury in HIV-1 but may also promote recovery from synaptodendritic damage. The HIV-1 transactivating protein (Tat) is produced during viral latency in the brain. Treatment with either daidzein or liquiritigenin restored the loss of synaptic connectivity produced by HIV-1 Tat. This neurorestoration was mediated by estrogen receptors (ER). These results suggest that plant-derived phytoestrogens may promote recovery from HIV-1-induced synaptodendritic damage.

"My body's a 50 year-old but my brain is definitely an 85 year-old": exploring the experiences of men ageing with HIV-associated neurocognitive challenges

INTRODUCTION

Research investigating HIV, neurocognition and ageing is well developed using neuropsychometric or other quantitative approaches; however, little is known about individuals' subjective experiences. The purpose of this article is to explore the experiences of men aged 50 and older who self-identify as having HIV-associated neurocognitive challenges. In particular, this study uses the Episodic Disability Framework (EDF) to explore participants' perceptions regarding: 1) symptoms/impairments, difficulties with day-to-day activities, challenges with social inclusion and uncertainty; 2) ageing as related to their HIV-associated neurocognitive challenges, and 3) the episodic nature of their HIV-associated neurocognitive challenges.

METHODS

This qualitative, interpretive study involved in-depth, semi-structured interviews with 12 men aged 50 years and older who self-identified as having HIV-associated neurocognitive challenges. Participants were recruited from a neurobehavioural research unit (NBRU) at a large hospital in Toronto, Canada. Data were analyzed thematically and with reference to the EDF.

RESULTS

Participants' experiences reflected all concepts within the EDF to some extent. Difficulties with daily activities were diverse but were addressed using similar living strategies. Participants described challenges with work and social relationships resulting from neurocognitive challenges. Participants downplayed the significance of uncertainty in their lives, which they attributed to effective living strategies. Most men reported confusion regarding the link between their neurocognitive challenges and ageing. Others discussed ageing as an asset that helped with coping.

CONCLUSIONS

This is the first study to use a disability framework to examine the subjective experiences of men ageing with HIV-associated neurocognitive challenges. Findings reframe the episodic disability experienced by these individuals as being predictably linked to certain triggers. As such, support for managing neurocognitive challenges could focus on triggers that exacerbate the condition in addition to the impairments themselves. The study also describes ageing as not only a source of problems but also as an asset among men growing older with HIV.

HIV-1 Tat protein variants: critical role for the cysteine region in synaptodendritic injury

HIV-1 enters the central nervous system early in infection; although HIV-1 does not directly infect neurons, HIV-1 may cause a variety of neurological disorders. Neuronal loss has been found in HIV-1, but synaptodendritic injury is more closely associated with the neurocognitive disorders of HIV-1. The HIV-1 transactivator of transcription (Tat) protein causes direct and indirect damage to neurons. The cysteine rich domain (residues 22-37) of Tat is important for producing neuronal death; however, little is known about the effects of the Tat protein functional domains on the dendritic network. The ability of HIV-1 Tat 1-101 Clades B and C, Tat 1-86 and Tat 1-72 proteins, as well as novel peptides (truncated 47-57, 1-72δ31-61, and 1-86 with a mutation at Cys22) to produce early synaptodendritic injury (24h), relative to later cell death (48h), was examined using cell culture. Treatment of primary hippocampal neurons with Tat proteins 1-72, 1-86 and 1-101B produced a significant early reduction in F-actin labeled puncta, implicating that these peptides play a role in synaptodendritic injury. Variants with a mutation, deletion, or lack of a cysteine rich region (1-86[Cys22], 1-101C, 1-72δ31-61, or 47-57) did not cause a significant reduction in F-actin rich puncta. Tat 1-72, 1-86, and 1-101B proteins did not significantly differ from one another, indicating that the second exon (73-86 or 73-101) does not play a significant role in the reduction of F-actin puncta. Conversely, peptides with a mutation, deletion, or lack of the cysteine rich domain (22-37) failed to produce a loss of F-actin puncta, indicating that the cysteine rich domain plays a key role in synaptodendritic injury. Collectively, these results suggest that for Tat proteins, 1) synaptodendritic injury occurs early, relative to cell death, and 2) the cysteine rich domain of the first exon is key for synaptic loss. Preventing such early synaptic loss may attenuate HIV-1 associated neurocognitive disorders.

Up-regulation of microRNA-142 in simian immunodeficiency virus encephalitis leads to repression of sirtuin1

MicroRNA (miR)-142 is up-regulated in the brain in HIV and SIV encephalitis (SIVE). We identified the cell types where miR-142 is up-regulated and its relevant downstream target. Fluorescent in situ hybridization combined with immunofluorescent labeling revealed that miR-142-3p and -5p are expressed within hippocampal neurons and myeloid cells in SIVE. Sirtuin1 (SIRT1) was predicted as a potential miR-142 target by analysis of its 3'-UTR and bioinformatic analysis of factors linked to altered hippocampal gene expression profile in SIVE. Overexpression of pre-miR-142 in HEK293T cells led to a 3.7-fold decrease in SIRT1 protein level. Examination of the individual effects of miR-142-5p and miR-142-3p through overexpression and inhibition studies revealed that significant effects on SIRT1 occurred only with miR-142-5p. Luciferase reporter assays revealed a 2.3-fold inhibition of expression due to interaction of miR-142 with the SIRT1 3'-UTR, mutation analysis revealed that only the miR-142-5p target site was active. MiR-142 expression in primary human neurons led to a small (1.3-fold) but significant decrease in SIRT1 protein level. Furthermore, qRT-PCR revealed up-regulation of miR-142-3p (6.4-fold) and -5p (3.9-fold) and down-regulation of SIRT1 (33-fold) in macrophages/microglia from animals with SIVE. We have therefore elucidated a miR-mediated mechanism of regulation of SIRT1 expression in SIVE.

HIV presenting as young-onset dementia

With the advent of retroviral therapies, the incidence of severe dementia associated with HIV has been reduced, although minor neurocognitive impairment is being increasingly recognized in the course of illness. We report a case of a young woman presenting with HIV-associated dementia and raise awareness of its presentation in young age and as the first presenting symptom.

Astrocytic expression of HIV-1 Nef impairs spatial and recognition memory

Despite the widespread use of antiretroviral therapy that effectively limits viral replication, memory impairment remains a dilemma for HIV infected people. In the CNS, HIV infection of astrocytes leads to the production of the HIV-1 Nef protein without viral replication. Post mortem studies have found Nef expression in hippocampal astrocytes of people with HIV associated dementia suggesting that astrocytic Nef may contribute to HIV associated cognitive impairment even when viral replication is suppressed. To test whether astrocytic expression of Nef is sufficient to induce cognitive deficits, we examined the effect of implanting primary rat astrocytes expressing Nef into the hippocampus on spatial and recognition memory. Rats implanted unilaterally with astrocytes expressing Nef showed impaired novel location and novel object recognition in comparison with controls implanted with astrocytes expressing green fluorescent protein (GFP). This impairment was correlated with an increase in chemokine ligand 2 (CCL2) expression and the infiltration of peripheral macrophages into the hippocampus at the site of injection. Furthermore, the Nef exposed rats exhibited a bilateral loss of CA3 neurons. These results suggest that Nef protein expressed by the implanted astrocytes activates the immune system leading to neuronal damage and spatial and recognition memory deficits. Therefore, the continued expression of Nef by astrocytes in the absence of viral replication has the potential to contribute to HIV associated cognitive impairment.

CCL3L1 gene copy number in individuals with and without HIV-associated neurocognitive disorder

BACKGROUND

CCL3L1 copy number variation has been implicated as a marker for susceptibility and immunity to human immunodeficiency virus (HIV)-1 infection and its pathogenic sequelae. Some of these findings have been confirmed in several, but not all, subsequent independent cohort studies. A three-fold risk for the development of HIV-associated dementia was reported in individuals possessing a CCL3L1 copy number below the ethnic group median combined with a detrimental CCR5 genotype. With the availability of antiretroviral therapy since 1996, there has been a significant decline in HIV-associated dementia, and milder forms of HIV-associated neurocognitive impairment (HAND) are now most prevalent. Moreover, patients are living longer with HIV-1 infection and it is recognized that aging may be a contributory factor to the development of cognitive disorder. Thus, the need for biomarkers that can be used in clinical practice to identify and provide optimal treatment for those at increased risk for HAND is great. HAND affects 20%-30% of HIV-infected individuals, and several genetic loci which have been shown to confer susceptibility to HIV infection may also modulate the development of neurocognitive disorder. The aim of this study was to determine whether CCL3L1 chemokine gene copy number in self-defined ethnic groups could differentiate HIV-infected individuals with and without HAND.

METHODS

Genomic DNA was isolated from buccal swabs or peripheral blood mononuclear cells obtained from HIV-infected patients with or without a diagnoses of neurocognitive dysfunction in the Northeast AIDS Dementia Cohort and National NeuroAIDS Tissue Consortium. To maintain a uniform standard, a quantitative polymerase chain reaction design similar to previous studies using Taqman probes and fixed input DNA between 2 ng and 10 ng was used to determine a CCL3L1 copy number. Standard curves with two-fold dilutions from 25 ng to 1.56 ng were generated. CCL3L1 copy number was determined in triplicate in 262 subjects using quantitative polymerase chain reaction and the relative quantitation method. Data were analyzed using analysis of variance, with significance defined as P < 0.05 and Bonferroni post hoc tests.

RESULTS

Significant differences as determined by analysis of variance in CCL3L1 copy number between African-Americans and Caucasians (P < 0.0001) were found, highlighting ethnic group differences in the copy number of this gene. However, there were no differences in CCL3L1 copy number across the neurocognitive groups within each ethnic group. The median CCL3L1 copy number in African-Americans of two and Caucasians of one in this study was significantly lower than the previously reported ethnic group means of two and four copies, respectively. A higher prevalence of abnormal cognition with a relative risk of four was seen in African-Americans versus Caucasians.

CONCLUSION

Based on this nested case-control study, CCL3L1 copy number alone may not be useful for distinguishing between individuals at risk for mild or severe neurocognitive disorder. Additional larger cohort studies are required to determine whether CCL3L1 copy number in combination with polymorphisms in other genes known to contribute to HIV risk will be useful in identifying those at increased risk for HAND.

Different surgical reconstruction modalities of the post-burn mutilated hand based on a prospective review of a cohort of patients*

This study covered 40 patients (22 females and 18 males) suffering from post-burn hand deformities admitted to Assiut University Hospital and Luxor International Hospital (Egypt) from June 2004 to May 2006. Their ages ranged between 4 and 45 yr (mean, 24.5 yr). They presented a variety of post-burn hand deformities, e.g. dorsal hand contracture (14 cases), volar contracture (10 cases), first web space contracture (3 cases), post-burn syndactyly (2 cases), wrist deformity (3 cases), skin and tendon affection (2 cases), and complex deformity (6 cases). All the patients underwent a variety of surgical procedures specific to the individual post-burn hand deformity. Post-operative splinting of the hand for 10 days was performed in patients with skin graft to prevent recontracture. The post-operative physiotherapy programme started in the second week in order to achieve good functional results. The follow-up period ranged from 6 to 20 months. The results were satisfactory in most of the cases as regards the quality of coverage, which was achieved in the majority of cases. In one case there was partial loss of the skin graft, which healed by secondary intention; full range of motion was achieved in most patients, but not those with joint affections. On the basis of our results, we can conclude that the management of post-burn hand deformities depends on several factors. Initial treatment of the burned hand is of great importance for the prevention of secondary deformities. In secondary burn management the first step is the release of the contracture, which should be complete and include all contracted structures. The second step is the proper selection of methods of coverage for resultant defects, using either skin grafts or flaps depending on the presence of exposed tendons, nerves, or joints. The third step in order to obtain a very good function is the activation of an intensive physiotherapy programme immediately after the operation.

Different surgical reconstruction modalities of the post-burn mutilated hand based on a prospective review of a cohort of patients

This study covered 40 patients (22 females and 18 males) suffering from post-burn hand deformities admitted to Assiut University Hospital and Luxor International Hospital (Egypt) from June 2004 to May 2006. Their ages ranged between 4 and 45 yr (mean, 24.5 yr). They presented a variety of post-burn hand deformities, e.g. dorsal hand contracture (14 cases), volar contracture (10 cases), first web space contracture (3 cases), post-burn syndactyly (2 cases), wrist deformity (3 cases), skin and tendon affection (2 cases), and complex deformity (6 cases). All the patients underwent a variety of surgical procedures specific to the individual post-burn hand deformity. Post-operative splinting of the hand for 10 days was performed in patients with skin graft to prevent recontracture. The post-operative physiotherapy programme started in the second week in order to achieve good functional results. The follow-up period ranged from 6 to 20 months. The results were satisfactory in most of the cases as regards the quality of coverage, which was achieved in the majority of cases. In one case there was partial loss of the skin graft, which healed by secondary intention; full range of motion was achieved in most patients, but not those with joint affections. On the basis of our results, we can conclude that the management of post-burn hand deformities depends on several factors. Initial treatment of the burned hand is of great importance for the prevention of secondary deformities. In secondary burn management the first step is the release of the contracture, which should be complete and include all contracted structures. The second step is the proper selection of methods of coverage for resultant defects, using either skin grafts or flaps depending on the presence of exposed tendons, nerves, or joints. The third step in order to obtain a very good function is the activation of an intensive physiotherapy programme immediately after the operation.

Management of the Acute Partial-thickness Burned Hand; Moist Exposed Burn Ointment or Silver Sulphadiazine Cream both Combined with a Polyethylene Bag

Hand burns predominantly affect young adults, and therefore have serious social and financial implications. In the present work, 106 patients with less than 25% body surface area burns and acute partial-thickness burned hands were managed using polyethylene bags and 1% local silver sulphadiazine (SSD) cream or moist exposed burn ointment (MEBO). Females made up 61.3% of the cases and flame burn was the majority cause (54.7%). There were no significant differences between the two groups regarding either the analgesic effect after local ointment application or hand movement inside the polyethylene bag. Local agent crustation over the wound was very evident in the hands managed by local 1% SSD cream (69.81%). On follow-up, the burned hands healed faster using local MEBO (10.48 versus 14.53 days), with fewer post-burn hand deformities and better active hand movements; however, the total cost until complete hand burn wound healing was higher with MEBO than with 1% SSD, although the final results were superior, with early return to work, when MEBO was used. We concluded that the use of MEBO as a topical agent and of polyethylene bags for the dressing of the acute partial-thickness burned hand accelerated healing; daily wound evaluation was easy as there was no crustation over it of the agent. It was more expensive than 1% SSD cream but presented fewer post-burn complications and more rapid healing, with shorter hospital stay.

The Policy of our Clinic in Early Escharectomy in Burns of the Hand

Early escharectomy in deep partial- and full-thickness burns of the hand has proved to have an advantage over late surgical treatment. It provides an improved functional and cosmetic result. Hand deformities, the need for secondary reconstructive procedures, and morbidity are significantly reduced. In our clinic we prefer to use early escharectomy in all full-thickness burns of the hand unless the patient's condition prevents it or unless the extent of the burns in the rest of the body would prevent improvement in the general outcome.

Acute dorsal hand burns in children

Hand burns in children, whether isolated or part of massive burns, require special attention. A crucial element in this respect is the preservation and full restoration of hand function. Most cases of severe sequelae after burns are associated with hand burns. From January 2002 to November 2004, 125 children with hand burns and other body burns were treated at the Centre of Burns and Plastic Surgery in Sofia, Bulgaria. This review presents our experience with 71 children with 89 burned hands in the region of the dorsal surface of the hand. Forty-nine hands had isolated dorsal surface burns, and 40 had combined burns, i.e. both dorsal and volar. Of all the hands treated, 69 had superficial burns, which epithelialized spontaneously. Twenty hands with deep dermal and full-thickness burns were subjected to sheet autografting. The review includes many details of the systematic approach to this type of burns. Optimal recovery of hand function can be achieved by accurate planning of treatment. Tracking of long-term results is also included in the general plan of behaviour in this type of burn. Our approach is conservative for superficial burns and active - with early excision and prompt closure with sheet autograft or, in extensive burns, allografting followed by covering with an autograft.