Biology subjects

Saag, M. S.

Publications and source records attributed to Saag, M. S..

3 recordsLinked to original sources

bioRxiv2020

Impact of glycan positioning on HIV-1 Env glycan shield density, function, and antibody recognition

N-glycans, which represent >50% mass of the HIV-1 envelope (Env) trimer, play important roles for virus-cell entry and immune evasion. How each glycan unit interacts to shape the Env protein-sugar complex and affects Env function is not well understood. Here, high-resolution glycomics analysis of two Env variants from the same donor, with differing functional characteristics and N-glycosylation-site composition, revealed that changes to key N-glycosylation-site not only affected the Env structure at distant locations, but also had a ripple effect on Env-wide glycan processing, virus infectivity, and antibody recognition and virus neutralization. Specifically, the N262 glycan, although not located in the CD4-binding site, controlled Env binding to the CD4 receptor, affected the recognition of Env by several glycan-dependent broadly neutralizing antibodies, and altered heterogeneity of glycosylation at several sites, with N156, N160, and N448 displaying limited glycan processing. Molecular dynamic simulations visualized how specific oligosaccharide positions can move to compensate for loss of a glycan. This study demonstrates how changes in individual glycan units can alter molecular dynamics and processing of the Env-glycan shield and, consequently, Env function.

microbiology↗

bioRxiv2019

Class of antiretroviral drugs and anemia risk in the current treatment era

OBJECTIVESAnemia is common among people living with HIV (PLWH) and has been associated with certain, often older, antiretroviral medications. Information on current antiretroviral therapy (ART) and anemia is limited. The objectives were to compare associations between anemia incidence or hemoglobin change with core ART classes in the current ART era.\n\nDESIGNRetrospective cohort study.\n\nSETTINGU.S.-based prospective clinical cohort of PLWH aged 18 and above receiving care at 8 sites between 1/2010-3/2018.\n\nPARTICIPANTS16,505 PLWH were included in this study.\n\nMAIN OUTCOME MEASURESAnemia risk and hemoglobin change were measured for person-time on a protease inhibitor (PI) or an integrase strand transfer inhibitor (INSTI), relative to a non-nucleoside reverse transcriptase inhibitor (NNRTI) reference. We also examined PLWH on multiple core classes. Cox proportional hazards regression analyses were conducted to measure associations between time-updated ART classes and incident anemia or severe anemia. Linear mixed effects models were used to examine relationships between ART classes and hemoglobin change.\n\nRESULTSDuring a median of 4.9 years of follow-up, 1,040 developed anemia and 488 developed severe anemia during. Compared to NNRTI use, INSTI-based regimens were associated with an increased risk of anemia (adjusted hazard ratio [aHR] 1.17, 95% confidence interval [CI] 0.94-1.47) and severe anemia (aHR1.55 95%CI 1.11-2.17), and a decrease in hemoglobin level. Time on multiple core classes was also associated with increased anemia risk (aHR 1.30, 95%CI 1.06-1.60) and severe anemia risk (aHR 1.35, 95%CI 0.99-1.85), while no associations were found for PI use.\n\nCONCLUSIONThese findings suggest INSTI use may increase the risk of anemia. If confirmed, screening for anemia development in users of INSTIs may be beneficial. Further research into underlying mechanisms is warranted.\n\nStrengths and limitations of this studyO_LIThis study utilized a large and geographically diverse population of PLWH in care across the U.S.\nC_LIO_LIThis study leveraged comprehensive clinical data, including information on diagnoses, medication use, laboratory test results, demographic information, and medical history.\nC_LIO_LIThis study investigated associations between specific types of ART core regimens and anemia risk.\nC_LIO_LIThis observational study is subject to residual confounding.\nC_LIO_LIThis study focused on anemia assessed from hemoglobin lab values taken at regular medical care visits without excluding participants with conditions strongly associated with hemoglobin level through non-traditional HIV mechanisms.\nC_LI

epidemiology↗

bioRxiv2018

Association between chronic hepatitis C virus infection and myocardial infarction in people living with HIV in the United States

Hepatitis C virus (HCV) is common among people living with HIV (PLWH). The potential for extrahepatic manifestations of HCV, including myocardial infarction (MI), is a topic of active research. MI is classified into types, predominantly atheroembolic Type 1 MI (T1MI) and supply-demand mismatch Type 2 MI (T2MI). We examined the association between HCV and MI in the CFAR Network of Integrated Clinical Systems (CNICS), a multi-center clinical cohort of PLWH. MIs were centrally adjudicated and categorized by type using the Universal MI definition. We estimated the association between chronic HCV (RNA+) and time to MI adjusting for demographic characteristics, cardiovascular risk factors, clinical characteristics and substance use. Among 24,755 PLWH aged [≥]18, there were 336 T1MI and 330 T2MI during a median of 4.2 years of follow-up. HCV was associated with a 68% greater risk of T2MI (adjusted hazard ratio (aHR) 1.68, 95% CI: 1.22, 2.30) but not T1MI (aHR 0.96, 95% CI: 0.63, 1.45). In a cause-specific analysis of T2MI, HCV was associated with a 2-fold greater risk of T2MI attributed to sepsis (aHR 2.26, 95% CI: 1.34, 3.81). Extrahepatic manifestations of HCV in this high-risk population are an important area for continued research.

epidemiology↗