Efficacy increase of lipid nanoparticles in vivo by inclusion of bis(monoacylglycerol)phosphate.

Aim: To investigate the effect of incorporating bis(monoacylglycerol)phosphate (BMP) lipid into a lipid nanoparticle and the functional transport of mRNA by the formulated nanoparticles in vivo. Materials & methods: The nanoparticles were prepared from ionizable lipid, 1,2-distearoyl-sn-glycerol-3-phosphocholine, cholesterol, 1,2-dimyristoyl-sn-glycerol PEG 2000, BMP and formulated mRNA encoding human erythropoietin. We measured the effect of BMP on physicochemical properties and impact on functional efficacy to transport mRNA to its target cells/tissue as measured by protein expression both in vitro and in vivo. Results: Lipid nanoparticles composed of BMP displayed increased endosomal membrane fusion and improved mRNA delivery to the cytosol. Conclusion: The results establish the foundation for future development of these nanoparticulated entities by designing new BMP derivatives and correlating structures to enhanced pharmacokinetic profiles.

Peripheral inflammation levels associated with degree of advanced brain aging in schizophrenia.

Brain structural abnormalities have been demonstrated in schizophrenia (SZ); these resemble those seen in typical aging, but are seen at younger ages. Furthermore, SZ is associated with accelerated global brain aging, as measured by brain structure-based brain predicted age difference (Brain-PAD). High heterogeneity exists in the degree of brain abnormalities in SZ, and individual differences may be related to levels of peripheral inflammation and may relate to cognitive deficits and negative symptoms. The goal of our study was to investigate the relationship between brain aging, peripheral inflammation, and symptoms of SZ. We hypothesized older brain-PAD in SZ vs. healthy comparison (HC) participants, as well as positive relationships of brain-PAD with peripheral inflammation markers and symptoms in SZ. We analyzed data from two cross-sectional studies in SZ (n = 26; M/F: 21/5) and HC (n = 28; 20/8) (22-64 years). Brain-PAD was calculated using a previously validated Gaussian process regression model applied to raw T1-weighted MRI data. Plasma levels of inflammatory biomarkers (CRP, Eotaxin, Fractalkine, IP10, IL6, IL10, ICAM1, IFNγ, MCP1, MIP1ß, SAA, TNFα, VEGF, VCAM1) and cognitive and negative symptoms were assessed. We observed a higher brain-PAD in SZ vs. HC, and advanced brain age relative to chronological age was related to higher peripheral levels of TNFα in the overall group and in the SZ group; other inflammatory markers were not related to brain-PAD. Within the SZ group, we observed no association between cognitive or negative symptoms and brain-PAD. These results support our hypothesis of advanced brain aging in SZ. Furthermore, our findings on the relationship of the pro-inflammatory cytokine TNFα with higher brain-PAD of SZ are relevant to explain heterogeneity of brain ages in SZ, but we did not find strong evidence for cognitive or negative symptom relationships with brain-PAD.

CSF markers of AD-related pathology relate specifically to memory impairment in older people with HIV: a pilot study.

Given the co-occurrence of memory impairment in HIV-associated neurocognitive disorders (HAND) and amnestic mild cognitive impairment/Alzheimer's disease (aMCI/AD), biomarkers are needed that can disentangle these conditions among people with HIV (PWH). We assessed whether cerebrospinal fluid (CSF) markers of AD could help in this effort by determining their relationship to learning and memory deficits versus cognitive deficits more characteristic of HAND than aMCI/AD (processing speed and complex visual/motor coordination) among 31 older PWH. CSF amyloid-ß42 phosphorylated-tau, amyloid-ß40/amyloid-ß42 and phosphorylated-tau/amyloid-ß42 ratio related to learning/memory performance but not HAND-related deficits, suggesting that these biomarkers may have utility in disentangling aMCI/AD from HAND.

Antiretroviral Tenofovir Induces Senescence-Associated ß-Galactosidase Activity in Primary Human Brain Vascular Cells in Multi-Layer Three-Dimensional Co-Culture.

Introduction In the current context of early diagnosis of HIV infection, immediate initiation of antiretroviral (ARV) therapy, and lifelong chronic treatment, the potential ARV toxicity is of particular concern. Emtricitabine (FTC) and tenofovir (TFV) are commonly used as backbone drugs in ARV regimens recommended for initial therapy of HIV infection. Here we assessed the effects of FTC and TFV exposure on senescence-associated ß-galactosidase (SA-ß-Gal) activity, a marker of cellular senescence, in human brain vascular cells. Design Multi-layer three-dimensional cell co-cultures and in vitro assays. Methods To mimic the small vessel wall structure in vivo, three types of primary human brain vascular cells (endothelial cells, smooth muscle cells, and pericytes) were co-cultured on three Alvetex Scaffold disks placed on top of each other in order (three-layer three-dimensional cell co-cultures) and exposed to clinically relevant concentrations of ARV drugs (FTC, TFV, or FTC+TFV combination) or vehicle for eight days (four or five biological replicates per condition, 18 replicates totally). The SA-ß-Gal activity was quantitatively assayed in vitro by using the chemiluminescent Galacto-Star System (T1012; Applied Biosystems, Thermo Fisher Scientific, Waltham, MA) in 54 protein lysates extracted from individual cell-culture disks. Three-factor analysis of variance (cell type, FTC, TFV) was used to assess differences in the SA-ß-Gal activity levels normalized by the corresponding total protein concentrations. Results There was a trend for the FTC by TFV interaction effect on SA-ß-Gal activity (P = 0.058). The effects of FTC and TFV were not significantly different among the three cell types. The overall effect of FTC was not significant when controlling for TFV and cell type. The overall effect of TFV was significant when controlling for FTC and cell type (F(1,48) = 30.61, P < 0.001, partial η2 = 0.389). In the absence of FTC, TFV raised SA-ß-Gal activity by 0.631 units on average, regardless of cell type (P < 0.001, partial η2 = 0.368). In the presence of FTC, TFV raised SA-ß-Gal activity by 0.303 units on average, regardless of cell type (P = 0.015, partial η2 = 0.118). Conclusion Our preliminary findings suggest that primary human brain vascular cells exposed to TFV at clinically relevant concentrations undergo cellular senescence. This potential adverse effect of TFV should be further studied in animal models of HIV infection.

Correlates of poor sleep based upon wrist actigraphy data in bipolar disorder.

BACKGROUND: Wrist-worn actigraphy can objectively measure sleep, and has advantages over self-report, particularly for people with Bipolar Disorder (BD) for whom self-reports might be influenced by affect. Clinically useful data reduction approaches are needed to explore these complex data. METHODS: We created a composite score of sleep metrics in BD based on 51 BD and 80 healthy comparison (HC) participants. Subjects wore an actigraph for up to 14 consecutive 24-h periods, and we assessed total sleep time (TST), wake after sleep onset (WASO), percent sleep (PS), and number of awakenings (NA). We focused on participants who had at least 5 nights of actigraphy data. We computed z-scores for within-person means of sleep measures for BD subjects versus HCs, which were averaged to create a composite measure. We correlated this composite with participant characteristics, and used LASSO regression to identify sleep measures best explaining variability in identified correlates. RESULTS: Sleep measures and the composite did not differ between BDs and HCs; however, there was considerable variability in z-scores among those with BD. In BDs, the composite score was higher in women (t(49) = 2.28, p = 0.027) and those who were employed (t(34) = 2.34, p = 0.025), and positively correlated with medication load (r = 0.41, p = 0.003) while negatively correlated with Young Mania Rating Scale (YMRS; r = -0.35, p = 0.030). In LASSO regression, TST and NA best explained medication load while PS best explained employment and YMRS. CONCLUSION: While a composite score of sleep metrics may provide useful information about sleep quality globally, our findings suggest that selection of theory-driven sleep measures may be more clinically meaningful.

Links between objective sleep and sleep variability measures and inflammatory markers in adults with bipolar disorder.

Premature mortality and increased physical comorbidity associated with bipolar disorder (BD) may be related to accelerated biological aging. Sleep disturbances and inflammation may be key mechanisms underlying accelerated aging in adults with BD. To our knowledge, these relationships have not been examined rigorously. This cross-sectional study included 50 adults with BD and 73 age- and sex-comparable non-psychiatric comparison (NC) subjects, age 26-65 years. Participants were assessed with wrist-worn actigraphy for total sleep time (TST), percent sleep (PS), and bed/wake times for 7 consecutive nights as well as completing scales for subjective sleep quality. Within-individual variability in sleep measures included intra-individual standard deviation (iSD) and atypicality of one evening's sleep. Blood-based inflammatory biomarkers included interleukin (IL)-6, C-reactive protein (CRP), and tumor necrosis factor-alpha (TNF-α). Linear regression analyses tested relationships of mean and iSD sleep variables with inflammatory marker levels; time-lagged analyses tested the influence of the previous evening's sleep on inflammation. BD participants had worse subjective sleep quality, as well as greater TST iSD and wake time iSD compared to the NC group. In all participants, higher TST iSD and lower mean PS were associated with higher IL-6 levels (p = 0.04, ηp2 = 0.042; p = 0.05, ηp2 = 0.039, respectively). Lower mean PS was associated with higher CRP levels (p = 0.05, ηp2 = 0.039). Atypicality of the previous night's TST predicted next day IL-6 levels (p = 0.05, ηp2 = 0.04). All of these relationships were present in both BD and NC groups and remained significant even after controlling for sleep medications. Overall, sleep measures and their variability may influence inflammatory markers in all adults. Thus, sleep may be linked to the inflammatory processes believed to underlie accelerated aging in BD.

Beta amyloid levels in cerebrospinal fluid of HIV-infected people vary by exposure to antiretroviral therapy.

BACKGROUND: HIV-associated neurocognitive disorders (HAND) persist despite the widespread implementation of combined antiretroviral therapy (ART). As people with HIV (PWH) age on ART regimens, the risk of age-related comorbidities, such as Alzheimer's disease may increase. However, questions remain as to whether HIV or ART will alter such risks. Beta amyloid (Aß) and phosphorylated-tau (p-tau) proteins are associated with Alzheimer's disease and their levels are altered in the CSF of Alzheimer's disease cases. METHODS: To better understand how these Alzheimer's disease-related markers are affected by HIV infection and ART, postmortem CSF collected from 70 well characterized HIV+ decedents was analyzed for Aß1-42, Aß1-40, and p-tau levels. RESULTS: Aß1-42 and Aß1-40 CSF levels were higher in cases that were exposed to ART. Aß1-42 and Aß1-40 CSF levels were also higher in cases on protease inhibitors compared with those with no exposure to protease inhibitors. Aß1-42 and Aß1-40 levels in CSF were lowest in HIV+ cases with HIV-associated dementia (HAD) and levels were highest in those diagnosed with asymptomatic neurocognitive impairment (ANI) and minor neurocognitive disorder (MND). Aß1-42 and Aß1-40 were inversely related with p-tau levels in all cases, as previously reported. CONCLUSION: These data suggest that ART exposure is associated with increased levels of Aß1-42 and Aß1-40 in the CSF. Also, HAD, but not ANI/MND diagnosis is associated with decreased levels of Aß1-42 and Aß1-40 in CSF, potentially suggesting impaired clearance. These data suggest that HIV infection and ART may impact pathogenic mechanisms involving Aß1-42 and Aß1-40, but not p-tau.

Loss of Immunohistochemical Reactivity in Association With Handling-Induced Dark Neurons in Mouse Brains.

The handling-induced dark neuron is a histological artifact observed in brain samples handled before fixation with aldehydes. To explore associations between dark neurons and immunohistochemical alterations in mouse brains, we examined protein products encoded by Cav3 (neuronal perikarya/neurites), Rbbp4 (neuronal nuclei), Gfap (astroglia), and Aif1 (microglia) genes in adjacent tissue sections. Here, dark neurons were incidental findings from our prior project, studying the effects of age and high-fat diet on metabolic homeostasis in male C57BL/6N mice. Available were brains from 4 study groups: middle-aged/control diet, middle-aged/high-fat diet, old/control diet, and old/high-fat diet. Young/control diet mice were used as baseline. The hemibrains were immersion-fixed with paraformaldehyde and paraffin-embedded. In the hippocampal formation, we found negative correlations between dark neuron hyperbasophilia and immunoreactivity for CAV3, RBBP4, and glial fibrillary acidic protein (GFAP) using quantitative image analysis. There was no significant difference in dark neuron hyperbasophilia or immunoreactivity for any protein examined among all groups. In contrast, in the hippocampal fimbria, old age seemed to be associated with higher immunoreactivity for GFAP and allograft inflammatory factor-1. Our findings suggest that loss of immunohistochemical reactivity for CAV3, RBBP4, and GFAP in the hippocampal formation is an artifact associated with the occurrence of dark neurons. The unawareness of dark neurons may lead to misinterpretation of immunohistochemical reactivity alterations.

Risk of developing cerebral ß-amyloid plaques with posttranslational modification among HIV-infected adults.

OBJECTIVES: Evidence of accelerated brain aging among HIV-infected adults argues for the increased risk of developing cerebral ß-amyloid (Aß) plaques. We compared the frequency of Aß plaque-bearing cases in our HIV cohort with that in a general cohort reported by Braak et al. We explored posttranslationally modified Aß forms (N3pE, E22P, phospho-Ser8) in plaques and E22P-Aß in the postmortem cerebrospinal fluid (CSF) in the HIV cohort. DESIGN: Clinicopathological study of HIV-infected adults. METHODS: To assess frontal Aß plaque deposition, we conducted immunohistochemistry for generic Aß (4G8) and three modified Aß forms. We determined CSF E22P-Aß levels by ELISA. RESULTS: We found 4G8-Aß plaques in 29% of 279 HIV-infected cases. Within the age range of 31-70 years, the frequency of 4G8-Aß plaque-bearing cases was higher in our HIV cohort (n = 273) compared with the general cohort (n = 1110) overall (29.3 vs. 25.8%) and across four age groups by decade (odds ratio 2.35, P < 0.0001). In HIV-infected cases with (n = 37) and without (n = 12) 4G8-Aß plaques, modified Aß forms occurred in order: N3pE, E22P, and phospho-Ser8. In CSF assays of HIV-infected cases with (n = 27; 17 focal, 10 widespread) and without (n = 11) 4G8-Aß plaques, the median E22P-Aß/Aß40 ratio was higher among cases with widespread plaques than in cases with focal or absent plaques (P = 0.047). CONCLUSION: Our findings suggest HIV-infected adults are at increased risk of developing cerebral Aß plaques. The occurrence of modified Aß forms in order suggests the progression stages of Aß plaque deposition. The potential for E22P-Aß as a CSF biomarker of cerebral Aß plaques should be investigated.

Tenofovir disoproxil fumarate induces peripheral neuropathy and alters inflammation and mitochondrial biogenesis in the brains of mice.

Mounting evidence suggests that antiretroviral therapy (ART) drugs may contribute to the prevalence of HIV-associated neurological dysfunction. The HIV envelope glycoprotein (gp120) is neurotoxic and has been linked to alterations in mitochondrial function and increased inflammatory gene expression, which are common neuropathological findings in HIV+ cases on ART with neurological disorders. Tenofovir disproxil fumarate (TDF) has been shown to affect neurogenesis in brains of mice and mitochondria in neurons. In this study, we hypothesized that TDF contributes to neurotoxicity by modulating mitochondrial biogenesis and inflammatory pathways. TDF administered to wild-type (wt) and GFAP-gp120 transgenic (tg) mice caused peripheral neuropathy, as indicated by nerve conduction slowing and thermal hyperalgesia. Conversely TDF protected gp120-tg mice from cognitive dysfunction. In the brains of wt and gp120-tg mice, TDF decreased expression of mitochondrial transcription factor A (TFAM). However, double immunolabelling revealed that TFAM was reduced in neurons and increased in astroglia in the hippocampi of TDF-treated wt and gp120-tg mice. TDF also increased expression of GFAP and decreased expression of IBA1 in the wt and gp120-tg mice. TDF increased tumor necrosis factor (TNF) α in wt mice. However, TDF reduced interleukin (IL) 1ß and TNFα mRNA in gp120-tg mouse brains. Primary human astroglia were exposed to increasing doses of TDF for 24 hours and then analyzed for mitochondrial alterations and inflammatory gene expression. In astroglia, TDF caused a dose-dependent increase in oxygen consumption rate, extracellular acidification rate and spare respiratory capacity, changes consistent with increased metabolism. TDF also reduced IL-1ß-mediated increases in IL-1ß and TNFα mRNA. These data demonstrate that TDF causes peripheral neuropathy in mice and alterations in inflammatory signaling and mitochondrial activity in the brain.

Mitochondrial biogenesis is altered in HIV+ brains exposed to ART: Implications for therapeutic targeting of astroglia.

The neuropathogenesis of HIV associated neurocognitive disorders (HAND) involves disruption of mitochondrial homeostasis and increased neuroinflammation. However, it is unknown if alterations in mitochondrial biogenesis in the brain underlie the neuropathogenesis of HAND. In this study, neuropathological and molecular analyses of mitochondrial biogenesis and inflammatory pathways were performed in brain specimens from a well-characterized cohort of HIV+ cases that were on antiretroviral regimens. In vitro investigations using primary human astroglia and neurons were used to probe the underlying mechanisms of mitochondrial alterations. In frontal cortices from HAND brains compared to cognitive normal brains, total levels of transcription factors that regulate mitochondrial biogenesis, peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) and transcription factor A, mitochondrial (TFAM) were decreased. Immunohistochemical analyses revealed that TFAM was decreased in neurons and increased in astroglia. These changes were accompanied by decreased total mitochondrial DNA per cell and increased levels of messenger RNA for the proinflammatory cytokine interleukin (IL)-1ß. To determine how IL-1ß affects astroglial bioenergetic processes and mitochondrial activity, human astroglial cultures were exposed to recombinant IL-1ß. IL-1ß induced mitochondrial activity within 30 min of treatment, altered mitochondrial related gene expression, altered mitochondrial morphology, enhanced adenoside triphosphate (ATP) utilization and increased the expression of inflammatory cytokines. WIN55,212-2 (WIN), an aminoalkylindole derivative and cannabinoid receptor agonist, blocked IL-1ß-induced bioenergetic fluctuations and inflammatory gene expression in astroglia independent of cannabinoid receptor (CB)1 and peroxisome proliferator-activated receptor (PPAR) γ. A PPARα antagonist reversed the anti-inflammatory effects of WIN in human astroglia. These results show that mitochondrial biogenesis is differentially regulated in neurons and astroglia in HAND brains and that targeting astroglial bioenergetic processes may be a strategy to modulate neuroinflammation.

Associations of regional amyloid-ß plaque and phospho-tau pathology with biological factors and neuropsychological functioning among HIV-infected adults.

With increasing age, the general population is increasingly vulnerable to the development of cerebral amyloid-ß (Aß) plaque and neuronal phospho-tau (p-tau) pathology. In HIV disease, prior studies of these neuropathologic changes were relatively limited. Here, we characterized Aß plaques and p-tau lesions by immunohistochemistry in relevant brain regions (prefrontal neocortex, putamen, basal-temporal neocortex, and hippocampus) of HIV-infected adults. We used multivariable logistic regression to predict regional Aß plaque or p-tau pathology based on demographic factors, apolipoprotein E (APOE) genotypes, HIV disease-related factors, and regional gliosis. We used multiple linear regression to predict T-scores in neuropsychological domains based on regional Aß plaque or p-tau pathology. We found that APOE ε4 alleles, older age, and higher plasma HIV-1 RNA predicted prefrontal Aß plaques (odds ratio (OR) 5.306, 1.045, and 0.699, respectively, n = 168). Older age predicted putamen Aß plaques (OR 1.064, n = 171). APOE ε4 alleles, hepatitis C virus seropositivity, and higher plasma HIV-1 RNA predicted hippocampus Aß plaques (OR 6.779, 6.138, and 0.589, respectively, n = 56). The p-tau lesions were sparse in the vast majority of affected cases. Lifetime substance use disorder and higher plasma HIV-1 RNA predicted putamen p-tau lesions (OR 0.278 and 0.638, respectively, n = 67). Older age and gliosis predicted hippocampus p-tau lesions (OR 1.128 and 0.592, respectively, n = 59). Prefrontal Aß plaques predicted lower speed of information processing (n = 159) and putamen Aß plaques predicted lower levels of attention and working memory (n = 88). Regional p-tau lesions were not significantly predictive of any neuropsychological domains. In conclusion, Aß plaque or p-tau pathology in different brain regions was predicted by different sets of biological factors. Aß plaques in prefrontal neocortex and putamen predicted poorer functioning in cognitive domains relevant to these brain regions. The absence of significant impact of regional p-tau lesions on neuropsychological functioning might be explained by the subthreshold burden of p-tau lesions.

Alterations in brain TREM2 and Amyloid-ß levels are associated with neurocognitive impairment in HIV-infected persons on antiretroviral therapy.

Neuroinflammation is a common pathological correlate of HIV-associated neurocognitive disorders (HAND) in individuals on antiretroviral therapy (ART). Triggering receptor expressed on myeloid cells 2 (TREM2) regulates neuroinflammation, clears extracellular Amyloid (A)-ß, surveys for damaged neurons, and orchestrates microglial differentiation. TREM2 has not been studied in HIV+ brain tissues. In this retrospective study, we investigated TREM2 expression levels and localization to microglia, Aß protein levels, and tumor necrosis factor (TNF)-α transcript levels in the frontal cortices of 52 HIV+ decedents. All donors had been on ART; 14 were cognitively normal (CN), 17 had an asymptomatic neurocognitive impairment (ANI), and 21 had a minor neurocognitive disorder (MND). Total TREM2 protein levels were increased in the soluble and decreased in the membrane-enriched fractions of MND brain tissues compared to CN; however, brains from MND Hispanics showed the most robust alterations in TREM2 as well as significantly increased TNF-α mRNA and Aß levels when compared to CN Hispanics. Significant alterations in the expression of total TREM2 protein and transcripts for TNF-α were not observed in non-Hispanics, despite higher levels of Aß in the non-Hispanic CN group compared to the non-Hispanic MND groups. These findings show that decreased and increased TREM2 in membrane-bound fractions and in soluble-enriched fractions, respectively, is associated with increased Aß and neuroinflammation in this cohort of HIV+ brains, particularly those identifying as Hispanics. These findings suggest a role for TREM2 in the brain of HIV+ individuals may deserve more investigation as a biomarker for HAND and as a possible therapeutic target. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.

Association of antiretroviral therapy with brain aging changes among HIV-infected adults.

OBJECTIVE: Antiretroviral therapy (ART) is currently recommended for all persons living with HIV (PLWH), regardless of their CD4 T-cell count, and should be continued throughout life. Nonetheless, vigilance of the safety of ART, including its neurotoxicity, must continue. We hypothesized that use of certain ART drugs might be associated with aging-related cerebral degenerative changes among PLWH. DESIGN: Clinicopathological study of PLWH who were using ART drugs at the last clinical assessment. METHODS: Using multivariable logistic regression, we tested associations between use of each specific ART drug (with reference to use of other ART drugs) and cerebral degenerative changes including neuronal phospho-tau lesions, ß-amyloid plaque deposition, microgliosis, and astrogliosis in the frontal cortex and putamen (immunohistochemistry), as well as cerebral small vessel disease (CSVD) in the forebrain white matter (standard histopathology), with relevant covariates being taken into account. The Bonferroni adjustment was applied. RESULTS: Darunavir use was associated with higher likelihood of neuronal phospho-tau lesions in the putamen [odds ratio (OR) 15.33, n = 93, P = 0.005]. Ritonavir use was associated with marked microgliosis in the putamen (OR 4.96, n = 101, P = 0.023). On the other hand, use of tenofovir disoproxil fumarate was associated with lower likelihood of ß-amyloid plaque deposition in the frontal cortex (OR 0.13, n = 102, P = 0.012). There was a trend toward an association between emtricitabine use and CSVD (OR 13.64, n = 75, P = 0.099). CONCLUSION: Our findings suggest that PLWH treated with darunavir and ritonavir may be at increased risk of aging-related cerebral degenerative changes.

Peripheral inflammation related to lower fMRI activation during a working memory task and resting functional connectivity among older adults: a preliminary study.

OBJECTIVE: Peripheral inflammation has been associated with adverse effects on cognition and brain structure in late life, a process called 'inflammaging.' Identifying biomarkers of preclinical cognitive decline is critical in the development of preventative therapies, and peripheral inflammation may be able to serve as an indicator of cognitive decline. However, little is known regarding the relationship between peripheral inflammation and brain structure and function among older adults. METHODS: Twenty-four older adults (mean age = 78) underwent a functional magnetic resonance imaging (fMRI) resting state functional connectivity scan, and a subset (n = 14) completed the n-Back working memory task in the scanner. All participants completed a blood draw, and inflammation was measured with interleukin 6 (IL-6) and C-Reactive Protein (CRP). RESULTS: Surprisingly, age was unrelated to measures of inflammation (IL-6, CRP) or brain function (default mode network (DMN) connectivity; working memory performance; blood oxygenation level dependent (BOLD) activation with higher working memory load). However, lower functional connectivity between the left parietal seed and all other DMN regions was associated with higher levels of IL-6 and CRP. Additionally, greater plasma concentration of IL-6 was associated with lower BOLD activation in the left middle frontal gyrus in response to increased working memory load. CONCLUSIONS: These preliminary findings support the importance of IL-6 and CRP in brain function among older adults. Frontal and parietal regions may be particularly sensitive to the effects of inflammation. Additionally, these findings provide preliminary evidence of inflammatory contributions to level of neural activity, even after accounting for vascular risk factors.

Abnormalities in chemokine levels in schizophrenia and their clinical correlates.

Chemokines are promising biomarkers of immune activation and inflammation, but evidence for chemokine abnormalities in schizophrenia and their relationship to clinical factors remains inconclusive. We aimed to understand chemokine-related diagnostic differences and clinical correlates using a comprehensive panel and studying a large, well-characterized sample of adults with and without schizophrenia. We studied 134 outpatients with schizophrenia or schizoaffective disorder and 112 healthy comparison (HC) individuals, 26 to 65years of age. Clinical measures were obtained, and plasma levels of 11 chemokines were assessed using multiplex immunoassay. Schizophrenia vs. HC differences were tested for each chemokine, adjusting for age, gender, body mass index, and current smoking status. We also examined whether age and gender relationships differed between diagnostic groups. Using logistic regression, we created a Chemokine Index (CI) and explored its clinical correlates. Levels of monocyte chemoattractant protein-1 (MCP-1/CCL2), macrophage inflammatory protein-1ß (MIP-1ß/CCL4), Eotaxin-1 (CCL11), thymus and activation-regulated chemokine (TARC/CCL17), and macrophage-derived chemokine (MDC/CCL22) were significantly higher in persons with schizophrenia than HCs. Group differences in TARC were reduced after adjusting for covariates. The CI, a linear combination of Eotaxin-1 and MDC levels, was positively associated with age, duration of schizophrenia, and severity of negative symptoms. Levels of chemokines with neuroimmune regulatory effects were higher in individuals with schizophrenia, particularly in older and chronic patients. Treatments aimed at normalizing chemokine levels might improve mental and physical health among schizophrenia patients as they age.

Age and High-Fat Diet Effects on Glutamine Synthetase Immunoreactivity in Liver and Hippocampus and Recognition Memory in Mice.

BACKGROUND: High-Fat Diet (HFD)-induced obesity may promote agerelated memory impairment via disturbances of ammonia-glutamine metabolism. OBJECTIVE: We studied the effects of age and long-term HFD exposure on Glutamine Synthetase (GS) expression in the liver and hippocampus and recognition memory in mice. METHODS: Adult (5-month-old) and aged (15-month-old) male C57BL/6 mice were exposed to control diet (CD, 14% calories from fat) or HFD (60% fat). Novel place recognition testing was conducted and tissue was collected after 4 and 5 months on HFD, respectively. Tissue GS expression levels were assessed using immunohistochemistry and image analysis. RESULTS: The obese mice developed moderate/severe hepatic steatosis. GS immunoreactivity was observed in perivenous hepatocytes and in hippocampal astrocytes and neuropil. Hepatic GS immunoreactivity density was higher in aged mice on HFD (n = 8) than CD (n = 13, P = 0.004). In aged mice, hippocampal GS immunoreactivity density was higher with HFD than CD (P = 0.037). In the novel place recognition test, aged mice were classified into impaired (n = 7) and unimpaired (n = 12), relative to adult mice (n = 22). Hippocampal GS immunoreactivity density was higher in impaired than unimpaired aged mice (P < 0.05). CONCLUSION: Long-term exposure of aged mice to HFD was associated with increased GS expression in the liver and hippocampus. Novel place recognition impairment in aged mice was associated with increased hippocampal GS expression. These findings suggest that excess ammonia is involved in the age-related effects of HFD exposure and in neurotoxicity.

Lifetime methamphetamine dependence is associated with cerebral microgliosis in HIV-1-infected adults.

Methamphetamine (Meth) use is common among HIV-infected persons. It remains unclear whether Meth dependence is associated with long-lasting degenerative changes in the brain parenchyma and microvasculature of HIV-infected individuals. We examined the postmortem brains of 78 HIV-infected adults, twenty of whom were diagnosed with lifetime Meth dependence (18 past and two current at the final follow-up visit). Using logistic regression models, we analyzed associations of Meth with cerebral gliosis (immunohistochemistry for ionized calcium-binding adapter molecule-1 (Iba1) and glial fibrillary acidic protein (GFAP) in frontal, temporo-parietal, and putamen-internal capsule regions), synaptodendritic loss (confocal microscopy for synaptophysin (SYP) and microtubule-associated protein-2 (MAP2) in frontal cortex), ß-amyloid plaque deposition (immunohistochemistry in frontal and temporo-parietal cortex and putamen), and arteriolosclerosis (histopathology in forebrain white matter). We found that Meth was associated with marked Iba1 gliosis in the temporo-parietal region (odds ratio, 4.42 (95 % confidence interval, 1.36, 14.39), p = 0.014, n = 62), which remained statistically significant after adjusting for HIV encephalitis, white matter lesions, and opportunistic diseases (n = 61); hepatitis C virus seropositivity (n = 54); and lifetime dependence on alcohol, opiates, and cannabis (n = 62). There was no significant association of Meth with GFAP gliosis, SYP or MAP2 loss, ß-amyloid plaque deposition, or arteriolosclerosis. In conclusion, we found lifetime Meth dependence to be associated with focal cerebral microgliosis among HIV-infected adults, but not with other brain degenerative changes examined. Some of the changes in select brain regions might be reversible following extended Meth abstinence or, alternatively, might have not been induced by Meth initially.

Cytokine secretion from brain macrophages infected with human immunodeficiency virus in vitro and treated with raltegravir.

BACKGROUND: Integrase inhibitors are a promising class of antiretroviral drugs to treat chronic human immunodeficiency virus (HIV) infection. During HIV infection, macrophages can extravasate from the blood to the brain, while producing chemotaxic proteins and cytokines, which have detrimental effects on central nervous system cells. The main goal of this study was to understand the effects of raltegravir (RAL) on human brain macrophage production of immune-mediators when infected with HIV, but did not compare with other antiretroviral agents. METHODS: Pro-inflammatory cytokines, IFN-γ, IL-10, IL-12-p70, IL-1, IL-8, TNF-α, and IL-6 were measured simultaneously in tissue culture supernatants from primary brain derived macrophages, microglia. We tested the effects of RAL on markers of astrocytosis and neurite integrity in primary human neuroglial cultures. RESULTS: RAL administered at 20 nM effectively suppressed HIV infection in microglia over 9 days. Only IL-8, IL-10, and TNF-α were above the detection limit in the majority of samples and RAL significantly suppressed the rate of cytokine production in HIV-infected microglia. During RAL-alone, the rate of IL-8 secretion was higher. CONCLUSIONS: RAL did not affect neurite area but inhibited astrocyte growth in the neuroglial cultures. Exploring the effects of RAL on pro-inflammatory molecule production in brain macrophages may contribute to designing ARV neuroprotective strategies in chronic HIV infection.