Cell-free mitochondiral DNA (mtDNA) is an immunogenic molecule associated with many inflammatory conditions. We evaluated the relationship between cell-free mtDNA in cerebrospinal fluid (CSF) and neurocognitive performance and inflammation during HIV infection. In a cross-sectional analysis, we evaluated the association of mtDNA levels with clinical assessments, inflammatory markers, and neurocognitive performance in 28 HIV-infected individuals. In CSF, we measured mtDNA levels by droplet digital PCR, and soluble CD14 and CD163, neurofilament light, and neopterin by ELISA. In blood and CSF, we measured soluble IP-10, MCP-1, TNF-α, and IL-6 by ELISA, and intracellular expression of IL-2, IFN-γ, and TNF-α in CD4+ and CD8+ T cells by flow cytometry. We also evaluated the relationship between CSF pleocytosis and mtDNA longitudinally in another set of five individuals participating in an antiretroviral treatment (ART) interruption study. Cell-free CSF mtDNA levels strongly correlated with neurocognitive performance among individuals with neurocognitive impairment (NCI) (r=0.77, p=0.001). CSF mtDNA also correlated with levels of IP-10 in CSF (r=0.70, p=0.007) and MCP-1 in blood plasma (r=0.66, p=0.01) in individuals with NCI. There were no significant associations between inflammatory markers and mtDNA in subjects without NCI, and levels of mtDNA did not differ between subjects with and without NCI. MtDNA levels preceded pleocytosis and HIV RNA following ART interruption. Cell-free mtDNA in CSF was strongly associated with the severity of neurocognitive dysfunction and inflammation only in individuals with NCI. Our findings suggest that within a subset of subjects cell-free CSF mtDNA is associated with inflammation and degree of NCI.

Objective In this work we evaluated the association of human immunodeficiency virus (HIV) infection and methamphetamine (METH) use with mitochondrial injury in the brain and its implication on neurocognitive impairment. Design Mitochondria carry their genome (mtDNA) and play a critical role in cellular processes in the central nervous system. METH is commonly used in HIV-infected populations. HIV infection and METH use can cause damage to mtDNA and lead to neurocognitive morbidity. We evaluated HIV infection and METH use with mitochondrial injury in the brain. Methods We obtained white and gray matter from Brodmann’s areas (BA) BA7, BA8, BA9, and BA46 of a) HIV-infected individuals with history of past METH use (HIV+METH+, n=16), b) HIV-infected individuals with no history of past METH use (HIV+METH−, n=11), and c) HIV-negative controls (HIV−METH−, n=30). We used the “common deletion,” a 4,977 bp mutation, as a measurement of mitochondrial injury, and quantified levels of mtDNA and “common deletion” by droplet digital PCR, and evaluated in relation to neurocognitive functioning (Global Deficit Score [GDS]). Results Levels of mtDNA and mitochondrial injury were highest in white matter of BA46. A higher relative proportion of mtDNA carrying the “common deletion” was associated with lower GDS (p<0.01) in HIV+METH+ but higher GDS (p<0.01) in HIV+METH−. Conclusions Increased mitochondrial injury was associated with worse neurocognitive function in HIV+METH− individuals. Among HIV+METH+ individuals, an opposite effect was seen.

BackgroundMitochondria are abundant organelles critical for energy metabolism and brain function. Mitochondrial DNA (mtDNA), released during cellular injury and as part of the innate immune response to viral pathogens, contains CpG motifs that act as TLR-9 ligands. We investigated relationships between cerebrospinal fluid (CSF) cell-free mtDNA levels and HIV viral load (VL), biomarkers of inflammation and iron transport, and neurocognitive (NC) function in the CNS HIV Antiretroviral Therapy Effects Research (CHARTER) cohort.MethodsWe quantified cell-free mtDNA in CSF by droplet digital PCR in 332 CHARTER participants who underwent comprehensive neuropsychiatric evaluation. NC performance was assessed using the global deficit score (GDS) as either a continuous or a binary measure (GDS ≥ 0.5, impaired vs. GDS < 0.5, unimpaired). CSF, clinical, and biomarker data from the earliest available time point were analyzed. Cell-free mtDNA associations with CSF inflammation and iron-related biomarkers [CXCL10, IL-6, IL-8, TNF-a, transferrin (TF), ceruloplasmin (CP), and vascular endothelial growth factor (VEGF)], VL, and GDS were evaluated by multivariable regression.ResultsCSF cell-free mtDNA levels were significantly lower in participants with undetectable (vs. detectable) VL in either plasma (p < 0.001) or CSF (p < 0.001) and in those on antiretroviral therapy (ART; p < 0.001). Participants on ART with undetectable VL in both CSF and plasma had lower mtDNA levels than those with detectable VL in both compartments (p = 0.001). Higher mtDNA levels were observed in participants in the highest vs. lowest tertile (T3 vs. T1) of CSF CXCL10 (T3 vs. T1, p < 0.001) and TNF-a (T3 vs. T1, p < 0.05) in unadjusted analyses. MtDNA levels also correlated with CSF leukocyte count. After adjusting for CSF leukocyte count and VL, mtDNA levels were also associated with other inflammation- and iron-related biomarkers in CSF, including TF (T3 vs. T1, p < 0.05) and CP (T3 vs. T1, p < 0.05). With additional correction for ART use, mtDNA was also negatively associated with CSF VEGF (p < 0.05) and IL-6 (p = 0.05). We observed no associations of CSF mtDNA levels with age or GDS-defined NC impairment.ConclusionsCSF cell-free mtDNA levels were associated with HIV RNA and ART status, as well as with biomarkers of iron transport and VEGF, a growth factor with known effects on mitochondrial integrity and autophagy. CSF mtDNA may be a biomarker of iron dysregulation and/or neuroinflammation during HIV infection.Electronic supplementary materialThe online version of this article (doi:10.1186/s12974-017-0848-z) contains supplementary material, which is available to authorized users.

Cell-free Mitochondrial DNA (mtDNA) is a highly immunogenic molecule that is associated with several inflammatory conditions and with neurocognitive impairment during untreated HIV infection. Here, we investigate how cell-free mtDNA in cerebrospinal fluid (CSF) is associated with inflammation, neuronal damage and neurocognitive functioning in the context of long-term suppressive antiretroviral therapy (ART). We quantified the levels of cell-free mtDNA in the CSF from 41 HIV-infected individuals with completely suppressed HIV RNA levels in blood plasma (<50 copies/mL) by droplet digital PCR. We measured soluble CD14, soluble CD163, IP-10, MCP-1, IL-6, IL-8, TNF-α, neopterin, and neurofilament-light (NFL) by immunoassays in CSF supernatant or blood plasma. Higher levels of mtDNA in CSF were associated with higher levels of MCP-1 (r=0.56, p<0.01) in CSF, and TNF-α (r=0.43, p<0.01), and IL-8 (r=0.44, p<0.01) in blood plasma. Subjects with a previous diagnosis of AIDS showed significantly higher levels of mtDNA (p<0.01) than subjects without AIDS. The associations between mtDNA and MCP-1 in CSF, and TNF-α in blood, remained significant after adjusting for previous diagnosis of AIDS (p<0.01). Additionally, higher levels of mtDNA were associated with a lower CD4 nadir (r=−0.41, p<0.01), and lower current CD4% (r=−0.34, p=0.03). Paradoxically, higher levels of mtDNA in CSF were significantly associated with better neurocognitive performance (r=0.43, p=0.02) and with less neuronal damage (i.e. lower NFL). Higher cell-free mtDNA is associated with inflammation during treated HIV-infection but the impact on neurocognitive functioning and neuronal damage remain unclear and may differ in the setting of suppressive ART.

Background Nucleos(t)ide reverse transcriptase inhibitor (NRTI)-sparing regimens may potentially minimize antiretroviral (ART) toxicities, but demonstrate mixed efficacy and toxicity results. The impact of an integrase strand transfer inhibitor (INSTI) and protease inhibitor (PI) regimen on HIV viral dynamics and T cell kinetics remains underdescribed. Objective To compare the effect of raltegravir + ritonavir boosted lopinavir (RAL + LPV/r) to efavirenz/tenofovir disoproxil fumarate/emtricitabine (EFV/TDF/FTC) on HIV kinetics and T cell dynamics. Methods Fifty participants naïve to ART underwent HIV viral kinetic sampling evaluated using biexponential mixed effects modeling. A subset of 28 subjects (with complete viral suppression) underwent flow cytometry and evaluation of soluble markers of inflammation at weeks 0, 4, and 48 of ART. Results RAL + LPV/r compared to EFV/TDF/FTC resulted in a prolonged first phase viral decay rate (18 vs. 13 days p < 0.01). From weeks 0 to 4, RAL + LPV/r was associated with a trend toward greater decreases in activated CD4+ T cells (−3.81 vs. −1.18 p = 0.09) and less decreases in activated effector memory CD4+ T cells (−0.63 vs. −2.69 p-0.07). These trends did not persist to week 48. No differences were noted at any time point for soluble markers of immune activation. Conclusions The prolonged first phase viral decay observed with RAL + LPV/r in persons starting ART did not result in differences in viral suppression at week 48. We also observed trends in declines in certain cellular markers of immune activation but it remains unclear if this could translate to long-term immunologic benefits in persons on an INSTI + PI.