Tesi sul tema "AIDS dementia complex"

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Bachelors
Health and Public Affairs
Nursing

The aim of the thesis was to undertake an evaluation of the neuropsychological functioning of non-demented and demented patients with advanced HIV-infection who have been treated with Highly Active Antiretroviral Therapy (HAART) for several years. One hundred and one non-demented HIV-infected individuals and 23 patients with mild or moderate AIDS Dementia Complex (ADC), from the outpatient clinics and Neurology department at St. Vincent's Hospital, Sydney, Australia were randomly selected to participate in a prospective study of the neurological and neuropsychological complications of HIV disease. All had advanced HIV-infection and all had been on HAART for five years on average. Thirty-one seronegative controls were recruited as controls. All participants completed a standard neuropsychological examination assessing nine cognitive domains. Non-demented advanced HIV-infected individuals participated in three follow-up visits. In addition, we report the results of a multi-centre cohort of 78 patients with mild to moderate ADC on HAART (Abacavir ADC trial). The main findings of our research were that the prevalence of neuropsychological impairment in advanced HIV-infected individuals remains equivalent to the era that preceded the introduction of HAART. Moreover, while complex attention / psychomotor speed remained a marker of HIV-related neuropsychological impairment in the HAART era, impairment in learning, memory and aspects of complex attention may be new indicators of HIV-associated neurocognitive impairment. While progression of neuropsychological impairment is associated with past HIV-related history of brain involvement, we demonstrated that deterioration does not occur in a linear fashion and that over a 27 month period neuropsychological performance stabilizes in the majority. Stabilization of performance may be related to relapses in the course of HIV-associated neurocognitive impairment and HAART optimization especially with antiretrovirals that have good brain tissue penetrance. Our research showed that plasma viral load and current CD4 cell count were generally not associated with the neuropsychological performance, but rather that nadir CD4 cell count was associated with neuropsychological performance suggesting a relation between past immune deterioration and current cognitive status. Cerebrospinal markers of immune and virological activity were found to be partly dissociated from current neurological in contrast to what was observed in the pre-HAART era. Future studies will need to evaluate new factors for underlying HIV-associated neurocognitive impairment as well as factors for underlying partial recovery.

The objective of the present study was to evaluate the relationship between a set of cofactors and severity of cognitive impairment, to determine if there were any factors which significantly predicted more severe neurocognitive deficits in persons with AIDS. Twenty-four male volunteers recruited from community groups and physician referrals participated. Subjects completed several self-report questionnaires eliciting information regarding demographics and risk factor variables, in addition to a comprehensive battery of neuropsychological tests. A severity of cognitive impairment summary score was computed for each subject, reflecting both the number of impaired tests and their distance in the impaired direction from normative data. Neither CD4 count, number of months since diagnosis of AIDS, number of AIDS-related illnesses, number of recent stressors, history of head injury/LOC, history of substance use, current or past psychiatric disorder, history of learning disability nor history of other medical illness were found to be significantly related to severity of cognitive impairment in this sample, after controlling for the effects of age, level of education, estimated premorbid IQ and mood status. However, no reliable conclusions could be drawn from this study because the small sample size resulted in an unacceptably low level of statistical power for the desired regression analysis. Exploratory analyses of variance revealed no significant group differences for any of the covariate or cofactor variables when subjects falling at the low, middle, and high ranges of severity of impairment were compared, with the exception of a possible inverse relationship with CD4 count. This was consistent with an exploratory stepwise regression analysis in which only CD4 count entered the model. Some potential limitations of the operational definitions used for the variables in this study were identified, and modifications were suggested. The results of additional exploratory analyses comparing group differences between the "globally impaired" and "unimpaired" subjects (Maj et al., 1994 criteria) on both the covariate and cofactor variables, and neuropsychological test performance, were also discussed.

A major product of HIV-infected and cytokine-stimulated monocytic-lineage cells is quinolinic acid (QUIN), a neurotoxic metabolite of the kynurenine pathway (KP) of L-tryptophan (L-Trp) metabolism. Despite the large number of neurotoxins found in HIV patients with AIDS Dementia Complex (ADC), only QUIN correlates with both the presence and severity of ADC. With treatment, cerebrospinal fluid (CSF) QUIN concentrations decrease proportionate to the degree of clinical and neuropsychological improvement. As endothelial cells (EC) of the blood-brain barrier (BBB) are the first brain-associated cell that a bloodborne pathogen would encounter, this project examined the BBB response to KP metabolites, as these are implicated in damage of the CNS associated with ADC. Using RT-PCR and HPLC/gas chromatographymass spectrometry (GC-MS), I found that cultured primary human BBB EC and pericytes constitutively expressed the KP. EC synthesised kynurenic acid (KA) constitutively, and after immune activation, kynurenine (KYN). Pericytes produced small amounts of picolinic acid and after immune activation, KYN. An SV40-transformed BBB EC showed no KP expression. By contrast, human umbilical vein EC only expressed low levels of KA after immune activation, however human dermal microvascular EC showed a similar constitutive and inducible KP to that in BBB EC. As T cells are central to primary HIV infection, I also examined KP expression in two CD4+ and one CD4- cell lines, but none showed either constitutive or inducible KP expression. I next examined how QUIN might interact with BBB EC. There was no binding of 3H-QUIN to cultured primary human BBB EC, however a biologically relevant concentration of QUIN induced changes in gene expression which adversely affected EC function, possibly mediated by lipid peroxidation and oxidative stress. The upregulated genes were of the heat shock protein family, and the downregulated genes were associated with regulation of cell adhesion, tight junction and cytoskeletal stability, metalloproteinase (MMP) regulation, apoptosis and G protein signaling. Immunofluorescence showed that QUIN induced morphological changes in BBB EC consistent with the changes in gene expression. Gelatin zymography showed that this was not mediated by MMPs, as constitutive MMP expression was unchanged. These data provide strong evidence for QUIN directly damaging the BBB in the context of HIV infection.

AIDS Dementia Complex (ADC) is a neurodegenerative disorder implicated in HIV-1 infection that is associated with elevated levels of the neurotoxin, quinolinic acid (QA) which causes a cascade of events to occur, leading to the production of reactive oxygen species (ROS), these being ultimately responsible for oxidative neurotoxicity. In clinical studies, Non-nucleoside reverse transcriptase inhibitors (NNRTIs), efavirenz (EFV) and nevirapine (NVP) have been shown to potentially delay the progressive degeneration of neurons, thus reducing the frequency and neurological deficits associated with ADC. Despite these neuroprotective implications, there is still no biochemical data to demonstrate the mechanisms through which these agents offer neuroprotection. The present study aims to elucidate and further characterize the possible antioxidant and neuroprotective mechanisms of NVP and EFV in vitro and in vivo, using QA-induced neurotoxicity as a model. Research has demonstrated that antioxidants and metal chelators have the ability to offer neuroprotection against free radical induced injury and may be beneficial in the prevention or treatment of neurodegeneration. Hence the antioxidant and metal binding properties of these agents were investigated respectively. Inorganic studies, including the 1, 1-diphenyl-2 picrylhydrazyl (DPPH) assay, show that these agents readily scavenge free radicals in vitro, thus postulating the antioxidant property of these agents. The enhancement of superoxide radical generation and iron mediated Fenton reaction by QA is related to lipid peroxidation in biological systems, the extent of which was assayed using the nitroblue tetrazolium and thiobarbituric acid method respectively. Both agents significantly curtail QA-induced lipid peroxidation and potentially scavenge superoxide anions generated by cyanide in vitro. Furthermore, in vivo results demonstrate the ability of NVP and EFV to protect hippocampal neurons against lipid peroxidation induced by QA and superoxide radicals generated as a consequence thereof. The alleviation of QA-induced oxidative stress in vitro possibly occurs through the binding of iron (II) and / or iron (III), and this argument is further strengthened by the ability of EFV and not NVP to reduce iron (II)-induced lipid peroxidation in vitro directly. In addition the ferrozine and electrochemistry assay were used to measure the extent of iron (II) Fe[superscript 2+] and iron (III) Fe[superscript 3+] chelation activity. Both assays demonstrate that these agents bind iron (II) and iron (III), and prevent redox recycling of iron and subsequent complexation of Fe[superscript 2+] with QA which enhances neuronal damage. Both NNRTIs inhibit the endogenous biosynthesis of QA by inhibiting liver tryptophan 2, 3-dioxygenase activity in vivo and subsequently increasing hippocampal serotonin levels. Furthermore, these agents reduce the turnover of hippocampal serotonin to 5-hydroxyindole acetic acid. NVP and not EFV increase 5-hydroxyindole acetic acid and norepinephrine levels in the hippocampus. The results of the pineal indole metabolism study show that NVP increases the synthesis of melatonin, but decreases N-acetylserotonin, 5-hydroxyindole acetic acid and 5-hydroxytryptophol levels. Furthermore, it shows that EFV decreases 5-hydroxyindole acetic acid and melatonin synthesis. Behavioural studies using a Morris water maze show that the post-treatment of rats with NVP and EFV significantly improves QA-induced spatial memory deficits in the hippocampus. This study therefore provides novel information regarding the neuroprotective mechanisms of NVP and EFV. These findings strengthen the argument that these NNRTIs not only have antiviral effects but possess potential neuroprotective properties, which may contribute to the effectiveness of these drugs in the treatment of ADC.

HIV associado a desordens neurocognitivas (HAND) continua a ser um grave problema atualmente devido à alta prevalência de suas formas mais brandas. Indivíduos HIV+ possuem o comprimento dos telômeros significativamente mais curtos nas células mononucleares do sangue periférico e células T CD8+, quando comparados aos indivíduos HIV negativos. Diante do exposto, o objetivo deste estudo foi avaliar a associação do comprimento dos telômeros de leucócitos em indivíduos infectados pelo HIV com deficiências cognitivas, pois ainda é um assunto bastante controverso. Métodos: Um total de 73 pacientes infectados pelo HIV-1 de ambos os sexos, com idades entre 20 a 60 anos, participaram deste estudo. Entre 19 indivíduos HIV(+) sem comprometimento cognitivo e 54 indivíduos HIV(+) com distúrbios neurocognitivos: 29 alteração neurocognitiva assintomático (ANI), 15 comprometimento neurocognitivo leve a moderado (MND) e, 10 demência associada ao HIV (HAD); 118 indivíduos HIV negativos formaram o grupo controle. Todos os participantes foram submetidos a uma série de testes neuropsicológicos previamente validados. Determinou-se a carga viral de HIV-1 nas células do líquido cefalorraquidiano (LCR) e em PBMC. Utilizou-se DNA a partir de leucócitos periféricos para calcular o comprimento de telômeros por PCR em tempo real. Resultados: O comprimento dos telômeros não foi associado com gêneros e diminuiu com a idade, independentemente do status de HIV. Indivíduos infectados pelo HIV-1com formas mais leves de deficiência neurocognitiva apresentaram um comprimento dos telômeros reduzida em comparação com pacientes HIV+ sem comprometimento neurocognitivo. Não houve correlação entre a carga viral plasmática e o tamanho dos telômeros. Conclusões: Nossos resultados sugerem que o comprimento dos telômeros pode ser considerado um marcador de senescência celular em indivíduos com alterações neurocognitivas
HIV associated neurocognitive disorders (HAND) remains a serious problem today because of the high prevalence of its milder forms. HIV + individuals have the length substantially shorter telomeres in peripheral blood mononuclear cells and CD8 + T cells compared to HIV negative individuals. Given the above, the objective of this study was to evaluate the association of telomere length of leukocyte (LTL) in HIV-infected individuals with cognitive disabilities because it is still a very controversial subject. Methods: A total of 73 patients infected with HIV-1 of both sexes, aged 20 to 60 years participated in this study. Among 19 HIV patients (+) without cognitive impairment and 54 HIV patients (+) with neurocognitive disorders: 29 asymptomatic neurocognitive disorder (ANI), 15 mild neurocognitive disorder to moderate (MND) and 10 HIVassociated dementia (HAD); 118 HIV-negative individuals formed the control group. All participants underwent a series of previously validated neuropsychological tests. Determined if the viral load of HIV-1 in cerebrospinal fluid cells (CSF) and in PBMC. We used DNA from peripheral leukocytes to calculate the length of telomeres by real time PCR. Results: The telomere length was not associated with genres and decreased with age, irrespective of HIV status. HIV-1-infected individuals with milder forms of neurocognitive impairment had a significantly length of telomeres reduced compared to HIV + patients without neurocognitive impairment. There was no correlation between plasma viral load and the size of telomeres. Conclusions: Our results suggest that telomere length can be considered a marker of cellular senescence in individuals with neurocognitive abnormalities

UVOD: Neurokognitivni poremećaj udružen sa HIVinfekcijom (HIV associated neurocognitive disorder- HAND) javlja se u oko polovine pacijenata sa HIV-om. HAND obuhvata spektar neuroloških poremećaja koji variraju od asimptomatskog neurokognitivnog poremećaja(ANI), preko blagog kognitivnog oštećenja, koje se naziva blagi kognitivni poremećaj (MND) do demencije udružene sa HIV-om (HAD). U evaluaciji i dijagnostici ovog poremećaja koriste se razne laboratorijske, kliničke i metode imidžinga, među kojima magnetno-rezonantni imidžing (MRI) zauzima posebno mesto u pogledu dijagnostike strukturnih poremećaja. Međutim, za dijagnostiku suptilnih supcelularnih neurobiohemijskih poremećaja neophodno je korišćenje magnetno-rezonantne spektroskopije (MRS). Klasično shvatanje promena u neurobiohemijskom profilu kod pacijenata sa HIV infekcijom uključuje: sniženje NAA (neuronskog markera) kao odraz neurodegeneracije, povišenje Cho (markera razgradnje membrana) kao odraz inflamacije/ apoptoze, povišenje mI (markera proliferacije mikroglije) kao odraz inflamacije i povišenje Glx+Gln (markera glutaminergične ravnoteže) kao odraz ekscitotoksičnosti. Do sada u literaturi nije opisano korišćenje multivokselske MRS mozga na HIV+ pacijentima. CILJEVI: Ciljevi studije su bili: utvrditi da li postoje promene u odnosima koncentracija metabolita u mozgu dobijenih metodom multivokselske MRS u neurološki asimptomatskih HIV+ pacijenata u poređenju sa zdravim kontrolnim ispitanicima,zatim da li postoje razlike između pacijenata na kombinovanoj antiretroviralnoj terapiji (cART) i pacijenata bez cART; utvrditi da li postoji i kakva je povezanost odnosa metabolita dobijenih MRS sa imunološkim parametrima HIV+ pacijenata i nivoom nadir CD4+ T-limfocita; i konačno, utvrditi da li postoji i kakva je povezanost dobijenih odnosa metabolita sa parametrima penetracije antiretroviralne terapije u centralni nervni sistem. ISPITANICI I METODE: U studiju je uključeno ukupno 114 ispitanika (32 HIV+ pacijenta na cART, prosečne starosti 41.97 godina (25-61); 28 HIV+ pacijenata bez cART, prosečne starosti 35.21 godina (24-52); 50 kontrolnih, zdravih subjekata prosečne starosti 36.56.godina (19-53)). Svi ispitanici su potpisali informisani pristanak za učešće u studiji. Ispitivanje je odobreno od strane Etičke komisije Instituta za onkologiju Vojvodine, kao i Etičke komisije Medicinskog fakulteta Univerziteta u Novom Sadu. Kriterijum za uključenje pacijenata u studiju je bio prisustvo HIV infekcije. Kriterijumi za isključivanje pacijenata iz studije su bili: prisustvo aktivne oportunističke infekcije, prisustvo aktivnog neurološkog oboljenja, podatak o aktivnoj zloupotrebi narkotika, koinfekcija virusom hepatitisa B i C, prisustvo lezija bele ili sive mase i kontraindikacije za snimanje na aparatu za magnetnu rezonancu. 4 ispitanika su isključena iz ispitivanja. Svim ispitanicima urađeni su skrining neurokognitivni testovi, kao i rutinska laboratorijska ispitivanja (broj CD4+, CD3+ i CD8+ limfocita). Nakon toga, svim ispitanicima urađen je konvencionalni MRI praćen multivokselskom MRS supratentorijalne suprakalozalne bele mase. Ispitivano je ukupno 12 voksela (6 u sivoj i 6 u beloj masi), odnosno preko 7900 spektara. Određeni su pikovi karakterističnih metabolita. Na metodi dugog eha analizirana su tri glavna pika: NAA na 2.0ppm, Cho na 3.2ppm i tCr na 3.ppm, izražena preko odnosa koncentracija NAA/Cr i Cho/Cr. Na metodi kratkog eha analizirani su signali NAA, Cho, Cr te mI na 3.5ppm i Glx+Gln na 2.2-2.4ppm. Ovi signali su izraženi kroz odnose koncentracija NAA/Cr, Cho/Cr, mI/Cr i (Glx+Gln)/Cr. Za statističku obradu podataka korišćen je IBM SPSS ver. 21.0. Deskriptivna statistika je uključila određivanje srednje vrednosti, minimuma, maksimuma i standardne devijacije. Razlike između posmatranih grupa ispitanika za sve kontinuirane varijable ispitivane su jednofaktorskom analizom varijanse (ANOVA) sa naknadnim (post-hoc) testovima za koje je korišćena metoda po Tukey-ju. Rezultati su prikazani u vidu srednjih vrednosti, standardne devijacije, najviše i najniže izmerene vrednosti (maksimum i minimum), i za svaki ispitivani parametar pridružena je vrednost F i p. Veza između kontinuiranih varijabli je ispitivana pomoću koeficijenta Pirsonove linearne korelacije, uz prethodnu proveru zadovoljavanja uslova o homogenosti varijansi, normalnosti raspodele i linearnosti. Vrednosti p<0.05 su uzimane kao statistički značajne. REZULTATI: Pokazano je da su HIV+ pacijenti na cART značajno stariji od druge dve grupe ispitanika. Nije pokazana značajna razlika u stepenu obrazovanja među grupama. Pokazano je da godine života statistički značajno utiču samo na koncentracije NAA/Cr, dok na odnose drugih metabolita ne utiču značajno. Utvrđeno je statistički značajno sniženje (p<0.05) koncentracija NAA/Cr dobijenih metodom dugog eha između tri grupe ispitanika na svim posmatranim vokselima. Naknadnim analizama utvrđena je statistički značajna razlika na 10/12 voksela između HIV+ pacijenata sa cART i zdravih, kao i između HIV+ pacijenata bez terapije i zdravih, dok su se koncentracije NAA/Cr značajno razlikovale između HIV+ pacijenata sa i bez cART samo na jednom vokselu (duboka frontalna bela masa levo). Utvrđena je statistički značajna razlika u smislu sniženja Cho/Cr odnosa dobijenih metodom dugog eha u 5/12 voksela, sa pojedinačnim vokselima koji su prikazivali razlike između grupa. Na metodi kratkog eha utvrđeno je značajno sniženje odnosa koncentracija NAA/Cr kod HIV+ pacijenata samo na tri voksela, pri čemu nisu prikazane značajne razlike između dve grupe pacijenata sa HIV infekcijom (sa i bez cART). Rezultati odnosa koncentracija Cho/Cr između tri gurpe pacijenata dobijeni metodom kratkog eha slični su rezultatima dobijenim na metodi dugog eha (statistički značajna razlika dobijena je na 5/12 voksela). Što se tiče odnosa koncentracija mI/Cr, uočeno je značajno povišenje ovog odnosa kod HIV+ pacijenata u odnosu na zdrave na 6/12 voksela. Prikazano je statistički značajno povišenje ovog markera kod pacijenata bez cART u odnosu na pacijente sa cART samo u regiji levog dorzalnog anteriornog cinguluma. Statistički značajno povišenje (Glx+Gln)/Cr odnosa je prikazano u regiji zadnjeg cinguluma desno kod pacijenata na terapiji u odnosu na pacijente bez terapije, dok na drugim vokselima nije prikazana značajna razlika. Vokseli 4, 7 i 10 su dali najviše informacija(supkortikalna bela masa frontalno levo, dorzalni prednji cingulum levo te parijetalni supkorteks leve cerebralne hemisfere), sa prikazanim značajnim razlikama u bar 4 odnosa metabolita. Prikazana je značajna pozitivna korelacija nadir CD4 + broja limfocita sa koncentracijama NAA/Cr, a negativna sa odnosima Cho/Cr i mI/Cr, što čini nadir CD4+ najboljim serološkim prediktorom neurodegenerativnog oštećenja. Pokazana je pozitivna korelacija indeksa penetracije lekova u monocite (ME) sa odnosima NAA/Cr i negativna korelacija indeksa penetracije lekova u centralni nervni sistem (CPE) sa Cho/Cr i mI/Cr. Došli smo do zakljulka da je ME indeks bolji marker neurodegenerativnog odgovora a CPE indeks bolji u monitoringu kontrole inflamacije. ZAKLJUČAK: Smatra se da HIV virus uzrokuje prerano starenje mozgašto je prvenstveno posledica direktnog oštećenja nervnih ćelija samim virusom (preko viralnih proteina, indukovanih citokina i hemokina). Pokazali smo da su neuronski gubitak i neurodegeneracija proces koji zahvata celokupan volumen mozga, dok su procesi inflamacije i proliferacije mikroglije svedeni na tačno određene regione, pretežno sive mase. Visoka senzitivnost multivokselske 1H-MRS sa korišćenjem senzitivnih površinskih kalemova omogućava mapiranje metabolita sa prostornom rezolucijom. MRS može dati ključni uvid u promene koncentracija metabolita mozga tokom razvoja infekcije od akutne i primarne do hronične. Vrlo brzo nakon serokonverzije, dolazi do detektabilnih promena u metabolitima mozga u smislu neuronskog oštećenja i inflamacije. U našem istraživanju su po prvi put analizirani rezultati protonske multivokselske MRS bele i sive mase velikog mozga u suprakalozalnom regionu. Utvrđeno je da postoje difuzne, ali ipak visoko regionalno-zavisne promene u odnosima neurometabolita kod pacijenata koji dobijaju antiretroviralnu terapiju i kod pacijenata koji je ne dobijaju, u poređenju sa zdravim kontrolnim ispitanicima (odgovarajućim po polu i starosti). Dodatne studije sa posmatranjem apsolutnih koncentracija neurometabolita, kao i longitudinalne studije u koje su uključeni HIV+ pacijenti u različitim fazama bolesti, su neophodne za dalje i bolje razumevanje neuropatogeneze HAND-a. MRS se pokazala uspešnom u detekciji efikasnosti određenih terapijskih opcija. Dva postojeća indeksa za procenu efikasnosti antiretroviralne terapije (CPE, ME) odvojeno pogađaju dva puta neuropatogeneze kognitivnog poremećaja, sa različitim uspehom u sveobuhvatnoj proceni efekta i efikasnosti terapije. U budućnosti je potrebna njihova pojedinačna modulacija ili kreiranje jedinstvenog indeksa, koji bi obuhvatio i efikasnost prolaza leka kroz hematoencefalnu barijeru i dejstvo na latentni rezervoar HIV-a u ćelijama monocitno-makrofagne loze.
INTRODUCTION: HIV associated neurocognitive disorder- HAND appears in about half of the HIV+ patients. HAND represents a spectrum of neurological disorders varying from asymptomatic neurocognitive impairment (ANI), over mild neurocognitive disorder (MND) to HIV associated dementia (HAD). For evaluation and diagnostics of this disorder, many laboratory, clinical and imaging methods are used, first of all magnetic resonance imaging (MRI). Nevertheless, for detecting subtle subcellullar neurobiochemical disorders, the use of magnetic resonance spectroscopy (MRS) is necessary. Classical pattern of neurobiochemical changes in HIV infection consist of: decrease in NAA (neuronal marker) depicting neurodegeneration, increase in Cho (metabolism on membrane marker) depicting inflammation/ apoptosis, increase in mI (marker of microglial proliferation) depicting inflammation and increase in Glx+Gln (glutaminergic balance marker) depicting the effect of excytotoxicity. To the best of our knowledge, this is the first study using multivoxel MRS of the brain in HIV+ patients. AIMS: The aims of this study were: to show whether there are differences in metabolites' ratios on multivoxel MRS in neurologically asymptomatic HIV+ patients compared to control subjects; whether there are differences in metabolites' ratios between patients on combined antiretroviral therapy (cART) and therapy-naive ones; whether there are correlations between matebolites' ratios and immunological parameters in HIV+ patients as well as with nadir CD4+ count; whether there are correlations between metabolites' ratios with parameters of drugs' penetration in central nervous system (CNS). SUBJECTS AND METHODS: Overall of 114 subjects were enrolled in the study (32 HIV+ paients on cART, average age 41.97 years (25-61); 28 HIV+ patients off cART, average age 35.21 years (24-52); 50 control subjects, average age 36.56 years (19-53)). All the subjects signed the informed consent. The study was ethically approved by Ethical committee of Vojvodina Oncology Institute and Ethical committee of Faculty of Medicine, University of Novi Sad. Inclusion criteria for HIV+ subjects were: the presence of HIV infection. Exclusion criteria included: active opportunistic infection, active neurological illness, usage of drugs of abuse, hepatitis B or C coinfection, presence of both white or grey matter lesions, and contraindications that apply for magnetic resonance (MR) examination. 4 subjects were excluded from the study due to the presence of white matter lesions (3 HIV+ and one control subject). Each patient performed International HIV Dementia Scale (IHDS), a screening test for evaluation of global cognitive status in HIV-infected patients. Baseline study laboratory variables were assessed (CD4+ T-lymphocyte count and plasma HIV RNA, nadir CD4+ counts and CD4+ T-cell counts at the moment of MR scan. Conventional MRI scan was followed by multivoxel MRS with both long and short echo. We analyzed 12 voxels (6 in grey and 6 in white matter) with overall of over 7900 spectra. Finally, we analyzed following dominant signals: on the long echo tCr (creatine plus phosphocreatine) at 3.0 ppm, NAA (N-acetyl-aspartate) at 2.0 ppm and Cho (choline containing compounds) at 3.2ppm (ratios of NAA/Cr and Cho/Cr were assessed); on the short echo tCr, NAA, Cho, (Glx+Gln) at 2.2-2.4ppm and mI (myoinositol) at 3.5ppm (ratios of NAA/Cr, Cho/Cr, (Glx+Gln)/Cr and mI/Cr were assessed. All statistical calculations were performed using IBM SPSS software (version 21.0, Chicago, IL, USA). Descriptive statistics included determination of mean values, minimum, maximum and standard deviation. Among-group differences (HIV infected subjects versus healthy controls) in acquired metabolite ratios were evaluated using ANOVA with post hoc Tukey test to determine the differences between separate groups. Due to a known impact of age and education on the NAA concentrations, differences in NAA/Cr ratios among groups were tested using ANCOVA, with age as a covariate variable. Testing relationships between continuous variables was performed using Pearson linear correlation. Statistical significance was set at value p<0.05. RESULTS: We showed that HIV+ patients on therapy were significantly older than the other two groups of patients. There was no significant difference in the level of education. We confirmed that the age significantly affects the level of NAA/Cr only.There was significant decrease (p<0.05) in NAA/Cr level on long echo MRS among three groups on all the observed voxels. Post hoc analysis showed that there was significant difference in 10/12 voxels between HIV+ patients on cART and healthy controls and between HIV+ patients off cART and controls, while NAA/Cr differed significantly between HIV+ patients on and off cART in only one voxel (deep frontal white matter on the left). There was decrease in Cho/Cr levels on long echo MRS in 5/12 voxels among three groups. On short echo MRS, we showed decrease in NAA/Cr level in 3/12 voxels, while there were no differences between two groups of HIV+ patients. Results of short echo MRS in the means of Cho/Cr resembled long echo MRS. There was significant increase in mI/Cr level in HIV+ patients in 6/12 voxels compared to healthy controls, while there was difference in only one voxel between HIV+ patients on and off therapy (dorsal part of anterior cingulate on the left). Significant increase in (Glx+Gln)/Cr level was present between HIV+ patients on and off therapy in the region of right posterior cingulate. Voxels 4, 7 and 10 were the most informative ones (subcortical frontal white matter on the left, dorsal part of left anterior cingulate and right posterior cingulate), showing significant differences in 4 metabolites' ratios. We showed positive correlation between nadir CD4+ count and NAA/Cr and negative correlation between nadir CD4+ count and Cho/Cr, and nadir CD4+ count and mI/Cr, which made nadir CD4+ count the best serological predictor of neurodegeneration. Positive correlation was showed between monocyte efficacy (ME) index and NAA/Cr, while negative correlation was present between CNS penetration efficacy (CPE), Cho/Cr and mI/Cr. We concluded that ME better depicted neurodegenerative process while CPE was better in monitoring of inflammation. CONCLUSIONS: HIV causes premature ageing of the brain, in the means of cognition, attention, working memory and executive function. These effects are due to direct affection of neurons by virus per se (viral proteins, induced cytokines and chemokynes). We showed tha neuronal loss and neurodegeneration affect the whole volume of the brain while inflammation and glial proliferation affect restricted areas predominantly in grey matter. High sensitivity of multivoxel MRS with use of sensitive surface coils enables metabolite mapping with high spatial resolution. MRS can give essential data on metabolites' changes during the evolution of the infection from acute, over primary to chronic. Early after seroconversion, metabolites' changes can be detected (neuronal dysfunction and inflammation).To the best of our knowledge, this is the first study using multivoxel MRS of the brain in HIV infection in human population, analyzing data from supracallosal grey and white matter. We showed the presence of diffuse but regionally highly specific changes in metabolites' ratios in patients on cART and off cART, compared to age and gender matched healthy controls. Additional studies with absolute concentrations of metabolites, as well as longitudinal studies with HIV+ patients in different stages of the disease, are necessary for better understanding of neuropathogenesis of HAND. We showed that MRS can be useful tool in evaluation of therapy regimens efficacy. Two available indices for evaluation of cART efficacy target two separate pathways of cognitive disorder pathogenesis, with different reliability in evaluation of effect and efficacy of applied therapy. In the future, their modulation or creation of new index is needed, in order to include drug delivery through the blood-brain barrier as well as the effect on latent reservoir of HIV in monocyte/macrophage cells.

Thesis (MScMedSc (Biomedical Sciences. Medical Physiology))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: HIV/AIDS is a global epidemic that accounts for a large percentage of the mortality in South Africa every year. Since the implementation of anti-retroviral treatment, HIV positive individuals have been living longer, and the cognitive impairment associated with the disease is becoming increasingly apparent. During the initial systemic infection of HIV, the virus migrates through the blood-brain barrier and inflicts axonal injury by causing upregulation of cytokines and neurotoxic proteins. HIV-associated dementia is a neuropsychological classification of cognitive impairment in HIV and a variety of symptoms have been classified as a part of the dementia complex. One of these is apathy, which is thought to be a precursor for dementia in HIV patients. Three groups of individuals have been recruited and scanned using magnetic resonance imaging (MRI) to examine changes in the brain. These are an HIV non-apathetic cohort, an HIV apathetic cohort and a healthy control cohort. Diffusion tensor imaging (DTI) is an MRI technique used to quantitatively assess white matter (WM) integrity using metrics such as fractional anisotropy (FA). Voxel-based analysis, tract-based spatial statistics (TBSS) and tractography are three established DTI analysis methods that have been applied in numerous studies. However, there are certain methodological strengths and limitations associated with each technique and therefore all three of these techniques were used to compare WM differences across groups. The frontal-subcortical pathways are known to be abnormal in apathy, and this has been demonstrated in a number of imaging studies. Most of these studies have examined apathy in the context of neurodegenerative disorders such as Alzheimer’s disease and Parkinson’s. However, to our knowledge this is the first DTI study in HIV apathetic patients. With the tractography method, the anterior thalamic radiation and the corpus callosum were reconstructed for each individual to determine whether there were any global changes in these tracts. No significant changes were found. However, a variety of regions in the WM were significantly abnormal in the HIV cohorts when comparing the data at a voxel-based level and using TBSS. This included areas such as the genu and splenium of the corpus callosum, the internal capsule and corona radiata. Changes in frontal WM for the HIV apathy group are an indication of dysfunction in the frontal-striatal circuits, and previous literature has implicated these circuits in the neuropathology of apathy in a variety of central nervous system (CNS) disorders.
AFRIKAANSE OPSOMMING: MIV/VIGS is `n wêreldwye epidemie wat verantwoordelik is vir `n hoë sterftesyfer in Suid- Afrika elke jaar. Sedert die inleiding van anti-retrovirale behandeling, het die MIV-positiewe populasie se lewensduur verleng. Tesame met langer lewensduur, het die kognitiewe verswakking wat geassosieer word met die siekte ook meer prominent na vore gekom. Gedurende die beginstadium van sistemiese infeksie in MIV is daar `n migrasie van die virus deur die bloed-breinskans. MIV kan indirek verantwoordelik wees vir aksonale beskadiging deur verhoging van neurotoksiese proteine en sitokinien te induseer. MIV-geassosieerde demensie is `n neurosielkundige klassifikasie van kognitiewe verswakking in MIV en verskeie simptome is al geïdentifiseer as deel van die demensie kompleks. Een van die simptome is apatie en daar word gespekuleer dat dit `n voorloper is vir demensie in MIV pasiënte. Drie groepe individue was gewerf vir die studie en geskandeer deur magnetiese resonansie beeldvorming (MRB) om sodoende veranderinge in die brein te ondersoek. Die groepe was onderskeidelik `n HIV nie-apatiese kohort, `n HIV apatiese kohort en `n gesonde kontrole kohort. Diffusie tensor beelding (DTB) is `n MRB tegniek wat toegepas word om witstof integriteit te meet deur gebruik te maak van maatstawwe soos fraksionele anisotropie (FA). “Voxel-based analysis”, “tract-based spatial statistics (TBSS)” en “tractography” is drie gevestigde DTB analitiese metodes wat al in talle studies toegepas was. Daar is egter sekere metodologiese voordele en beperkings verbonde aan elke tegniek en daarom is al drie tegnieke gebruik om witstof verskille tussen groepe te vergelyk. Die frontale-subkortikale roetes in die brein is bekend vir abnormaliteite in apatie en dit was ook al gedemonstreer in verskeie studies. Die meeste van die studies het apatie ondersoek in die konteks van neurodegeneratiewe siektes soos Alzheimer se siekte en Parkinson se siekte. Maar sover ons weet is hierdie die eerste DTB studie in MIV pasiënte met apatie. Met die “tractography” metode was die anterior thalamic radiation en corpus callosum herbou vir elke individu. Dit was om te bepaal of daar enige globale veranderinge is in hierdie gebiede, maar geen beduidende veranderinge is gevind nie.`n Verskeidenheid van gebiede in die witstof was beduidend abnormaal in die MIV kohorte wanneer die data vergelyk was met “TBSS” en “voxel-based analysis.” Dit het gebiede ingesluit soos die genu en splenium van die corpus callosum, die internal capsule en die corona radiata. Veranderinge in die frontale witstof vir die MIVapatie groep is `n aanduiding van disfunksie in die frontale-striatale bane. Vorige literatuur impliseer dat hierdie bane betrokke is in die neuro-patologie van apatie in verskeie sentrale senuweestelsel (SS) steurings.

Thesis (MPhil)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: The HIV/AIDS pandemic has led to millions of deaths; disability for the sufferers and multiple socioeconomic effects on HIV infected and affected individuals. Among the factors affecting people living with HIV/AIDS that may contribute to HIV related disability is mental illness such as HIV related manias and depression. ‘HIV counselors’ make up part of the team at the forefront of HIV treatment and management in Uganda but little is known about their perceptions of mental illness. This study therefore sought to explore the perceptions of mental illness among HIV counselors in Uganda. A qualitative study was conducted. Ten individual interviews and three focus group discussions were carried out among 31 HIV counselors. They were selected from five HIV treatment centers in Kampala district, Uganda. An interview guide based on Kleinman’s explanatory model of illness with case vignettes depicting depression, alcohol abuse, mania, and psychosis were used to facilitate discussion. Data was thematically analyzed. HIV counselors exhibited some knowledge concerning depression among HIV positive clients, with some viewing the symptoms of depression as “understandable sadness” arising from the HIV client’s psychosocial reality which is rife with poverty, stigma and lack of social support. Counselors also reported that some of their client’s physical symptoms were a result of their emotional problems. Mania and psychosis were attributed to religious beliefs and witchcraft; and in some cases disease progression or HIV drugs. Chronic alcohol abuse, despite continuous counseling was seen as a waste of the counselor’s time in face of overwhelming numbers of clients per day. Such clients, along with clients with suicidal ideations were often threatened or ignored. Counselors agreed that they needed training on assessment of mental illness, and how difficult cases could be referred.
AFRIKAANSE OPSOMMING: Die MIV/VIGS pandemie het al miljoene sterftes tot gevolg gehad; ook ongeskiktheid vir die lyers en veelvuldige sosio-ekonomiese gevolge vir individue met MIV sowel as ander individue wat daardeur geraak word. Van die faktore wat ‘n uitwerking op mense het wat leef met MIV/VIGS en wat kan bydra tot HIV ongeskiktheid, is geestesversteurings soos HIV verwante manies en depressie. “MIV-voorligters” is deel van ‘n span wat aan die voorpunt staan van die behandeling en bestuur van MIV in Uganda, maar min is bekend oor hulle persepsies van geestesversteuring. In die onderhawige studie is MIV-voorligters in Uganda se persepsies van geestesversteuring ondersoek. ‘n Kwalitatiewe studie is onderneem. Tien individuele onderhoude en drie fokusgroepbesprekings is gedoen onder 31 MIV-voorligters. Hulle is geselekteer uit vyf MIV-behandelingsentrums in die Kampala-distrik, Uganda. ‘n Onderhoudskedule gebaseer op Kleinman se verklarende siektemodel, bestaande uit karakterskets-gevallestudies wat depressie, alkoholmisbruik, manie en psigose uitbeeld, is gebruik om die besprekings te fasiliteer. Die data is tematies ontleed. MIV-voorligters het getoon dat hulle in ‘n mate oor kennis beskik ten opsigte van depressie by MIV-positiewe kliënte. Sommige voorligters het die simptome van depressie beskou as “verstaanbare droewigheid” wat voortspruit uit die MIV-kliënt se psigososiale werklikheid, bestaande uit armoede, stigma en ‘n gebrek aan sosiale ondersteuning. Voorligters het ook gerapporteer dat sommige kliënte se fisiese simptome die gevolg is van emosionele probleme. Manie en psigose is toegeskryf aan godsdienstige oortuigings and toordery; en in sommige gevalle aan progressie van die siekte of MIVmedisyne. As gevolg van die feit dat voorligters daagliks oorlaai word met kliëntgetalle, is kliënte wat kronies alkohol gebruik beskou as ‘n vermorsing van voorligters se tyd, ten spyte van voortdurende voorligting. Sulke kliënte, tesame met kliënte wat selfmoordneigings getoon het, is dikwels gedreig of geïgnoreer. Voorligters was dit eens dat hulle opleiding benodig in die assessering van geestessiekte asook leiding oor hoe om moeilike gevalle te verwys.

Axonal degeneration is a major pathological feature of the central nervous system (CNS) inflammatory demyelinating disease multiple sclerosis (MS). This axonal degeneration has major consequences, as functional axonal regeneration in the CNS is largely absent. Cumulative axonal degeneration is the likely cause of the majority of progressive MS-related disability, and therefore, the need for novel neuroprotective therapies for MS exists. Experimental autoimmune encephalomyelitis (EAE), an animal model of MS pathology, also produces axonal injury. In particular, the optic nerve and spinal cord are key sites of neuroinflammation in mouse EAE. By utilizing this model, the short term and long term effects of the putative neuroprotective cytokine, leukaemia inhibitory factor (LIF), were investigated in the optic nerve and spinal cord utilising a number of outcome measures of axonal dysfunction. These included MRI measures of water diffusivity along (ADC ||) and across (ADC┴) the optic nerves, serum levels of phosphorylated neurofilament heavy chain subunit (pNF-H) and histological morphometric measures. LIF treatment reduced EAE grade and pNF-H plasma levels, decreased ADC┴, but had no effect on ADC ||, axon counts or inflammatory infiltration.
In contrast, genetic deletion of LIF and its sister cytokine ciliary neurotrophic factor (CNTF), not only increased EAE grade and pNF-H levels, but also decreased optic nerve ADC|| and optic nerve and spinal cord axon densities. After reviewing current literature, we hypothesize that the target cell for endogenously upregulated LIF in EAE may be the neuron or axon, whereas the target cell for exogenously administered therapeutic LIF may be another cell type, possibly infiltrating macrophages and activated microglial cells. LIF antagonist treatment did not have any affect on EAE grade, pNF-H levels or MRI parameters. This lack of effect may be due to the inability of the LIF antagonist to enter the CNS, supporting the hypothesis that endogenous LIF has a centrally acting mechanism.

Drug delivery to the brain has challenged medical professionals for several decades, with 98% of small molecules and 100% of large molecules unable to cross the blood brain barrier (BBB). Biocompatible, biodegradable polymers have been extensively researched for the oral delivery of therapeutic agents, but to date has not been successfully manipulated for the formulation of an implantable device. We have therefore utilised such polymers for the formulation and design of an implantable nanoenabled multipolymeric drug delivery device (NMDDD) for the management of AIDS Dementia Complex (ADC). ADC is a central nervous system (CNS) complication of HIV, associated with a host of debilitating cognitive, motor and behavioural symptoms. ADC remains a serious manifestation of HIV/AIDS in both developing and developed countries, affecting both adults and children, with death expected within 6 months of initial diagnosis. Zidovudine (AZT), the current gold standard for the management of ADC, has demonstrated the best penetration into the CNS. It is capable of reducing viral replication in the CNS and managing neurological abnormalities associated with ADC, with clinical efficacy evidenced by the decline in morbidity and mortality of patients treated with this drug. Nanotechnology, an interdisciplinary field of research, involving the manipulation of matter on a submicron level, is receiving emerging interest for the formulation of novel drug delivery systems. As they can potentially be manipulated to react in a bioresponsive manner, nanopharmaceuticals have received much attention for site-specific drug delivery and were therefore employed in the formulation of an implantable NMDDD, with AZT employed as the model drug, for the management of ADC. Nanoparticles were prepared by means of an approach utilising controlled gelation of alginate, employing cationic crosslinking of the anionic alginate to precipitate nanoparticles. A 3-factor Box-Behnken statistical design was employed for the optimisation of nanoparticle and multipolymeric scaffold formulations. Nanoparticles measuring 68.04nm (SD<0.0002) in size with a zeta potential of -13.4mV (SD<0.0005) were formulated. Nanoparticles presented with a mean dissolution time (MDT) of 46.046 hours 30 days post exposure to phosphate buffered saline (PBS), pH 7.4. In an attempt to further retard drug release and to formulate a device for implantation in the frontal lobe of the brain, nanoparticles were dispersed within a robust multipolymeric matrix. Matrix erosion was calculated at 28%w/w (SD<0.001) for multipolymeric scaffold and a matrix resilience of 4.451%w/w (SD<0.007) was observed 30 days post exposure to PBS, indicating slow degradation of the NMDDD. MDT was reduced to 12.570 hours (SD<0.0005) with dispersion of the nanoparticles within a polymer matrix, supporting the application of the drug-loaded MDDD in the management of ADC patients. The optimised multipolymeric nanoparticulate scaffold was implanted into the frontal lobe of the rat brain, for investigation of drug release characteristics and tissue response to the device following in vivo administration.

Title page, table of contents and summary only. The complete thesis in print form is available from the University of Adelaide Library.
HIV-1 infection of astrocytes is involved in HIV-1 induced neurological diseases and is a possible source of viral persistence. In situ studies of post mortem brain tissue indicate that HIV-1 infection of astrocytes does occur, but is restricted. Previous in vitro studies have revealed intrinsic intracellular blocks to HIV-1 transcription and translation in astrocytes. The early viral replication steps of entry, reverse transcription and integration have not been previously characterised in detail in astrocytes, and are the focus of this study.
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Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2007