HIV infection and high density lipoprotein metabolism

Inflammation in HIV and Its Impact on Atherosclerotic Cardiovascular Disease

People living with HIV have a 1.5- to 2-fold increased risk of developing cardiovascular disease. Despite treatment with highly effective antiretroviral therapy, people living with HIV have chronic inflammation that makes them susceptible to multiple comorbidities. Several factors, including the HIV reservoir, coinfections, clonal hematopoiesis of indeterminate potential (CHIP), microbial translocation, and antiretroviral therapy, may contribute to the chronic state of inflammation. Within the innate immune system, macrophages harbor latent HIV and are among the prominent immune cells present in atheroma during the progression of atherosclerosis. They secrete inflammatory cytokines such as IL (interleukin)-6 and tumor necrosis-α that stimulate the expression of adhesion molecules on the endothelium. This leads to the recruitment of other immune cells, including cluster of differentiation (CD)8+ and CD4+ T cells, also present in early and late atheroma. As such, cells of the innate and adaptive immune systems contribute to both systemic inflammation and vascular inflammation. On a molecular level, HIV-1 primes the NLRP3 (NLR family pyrin domain containing 3) inflammasome, leading to an increased expression of IL-1β, which is important for cardiovascular outcomes. Moreover, activation of TLRs (toll-like receptors) by HIV, gut microbes, and substance abuse further activates the NLRP3 inflammasome pathway. Finally, HIV proteins such as Nef (negative regulatory factor) can inhibit cholesterol efflux in monocytes and macrophages through direct action on the cholesterol transporter ABCA1 (ATP-binding cassette transporter A1), which promotes the formation of foam cells and the progression of atherosclerotic plaque. Here, we summarize the stages of atherosclerosis in the context of HIV, highlighting the effects of HIV, coinfections, and antiretroviral therapy on cells of the innate and adaptive immune system and describe current and future interventions to reduce residual inflammation and improve cardiovascular outcomes among people living with HIV.

Echocardiographic assessment of left cardiac structure and function in antiretroviral therapy (ART)-naïve people living with HIV/AIDS

BACKGROUND

Patients with human immunodeficiency virus (HIV) are at a significantly higher risk of cardiovascular disease (CVD) compared to HIV-negative people. Left heart dysfunction is the most common cardiac complication in people living with HIV/acquired immune deficiency syndrome (PLWHA), and diastolic dysfunction is an important predictor of cardiovascular events. The aims of this study were (1) to detect changes in left cardiac structure and function in antiretroviral therapy (ART)-naive PLWHA using echocardiography; and (2) to investigate the risk factors for the development of left ventricular diastolic dysfunction (LVDD) in ART-naive PLWHA.

METHODS

We retrospectively included 105 ART-naïve PLWHA and included 90 healthy subjects as controls to compare the differences in left heart structure and function between the two groups. Univariate and multifactorial logistic regression were employed to explore the risk factors of the development of LVDD in ART-naive PLWHA.

RESULTS

The left ventricular end-diastolic internal diameter (LVEDD), left ventricular mass index (LVMI), and left atrial volume index (LAVI) were significantly greater in PLWHA than in controls (p < .05). The E/A ratio, lateral e' velocity, and mitral deceleration time were significantly lower in PLWHA than in controls (p < .05). Average E/e' ratio was significantly higher in PLWHA than in controls (p < .05). Left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were not significantly different between PLWHA and controls (p > .05). Multifactorial logistic regression analysis showed that age, body mass index (BMI), and CD4⁺ count <200 cells/μL were independent risk factors for LVDD in ART-naive PLWHA (OR = 1.781, 1.228, 3.683, p < .05).

CONCLUSIONS

Left ventricular systolic function did not differ between PLWHA and controls, and left ventricular diastolic function was lower in PLWHA than in controls. Age, BMI, and CD4⁺ count were independent factors affecting LVDD in ART-naive PLWHA.

Study on plasma metabolomics for HIV/AIDS patients treated by HAART based on LC/MS-MS

Background: Metabolomics can be applied to the clinical diagnosis and treatment evaluation of acquired immune deficiency syndrome (AIDS). AIDS biomarkers have become a new direction of AIDS research providing clinical guidance for diagnosis.

Objective: We sought to apply both untargeted and targeted metabolomic profiling to identify potential biomarkers for AIDS patients.

Methods: A liquid chromatography-tandem mass spectrometry (LC-MS/MS) based untargeted metabolomic profiling was performed on plasma samples of patients before and after highly active antiretroviral therapy (HAART) treatment as well as healthy volunteers to identify potential AIDS biomarkers. Targeted quantitative analysis was performed on the potential biomarkers screened from untargeted metabolic profiling for verification.

Results: Using the Mass Profiler Professional and the MassHunter, several potential biomarkers have been found by LC-MS/MS in the untargeted metabolomic study. High-resolution MS and MS/MS were used to analyze fragmentation rules of the metabolites, with comparisons of related standards. Several potential biomarkers have been identified, including PS(O-18:0/0:0), sphingosine, PE (21:0/0:0), and 1-Linoleoyl Glycerol. Targeted quantitative analysis showed that sphingosine and 1-Linoleoyl Glycerol might be closely related to HIV/AIDS, which may be the potential biomarkers to the diagnosis.

Conclusion: We conducted untargeted metabolomic profiling, which indicates that several metabolites should be considered potential biomarkers for AIDS patients. Further targeted metabolomic research verified that d-Sphingosine and 1-Linoleoyl glycerol as the diagnostic biomarker of AIDS.

Triglyceride/High-Density Lipoprotein Cholesterol Ratio is Associated with the Mortality of COVID-19: A Retrospective Study in China

Background

Triglyceride to high density lipoprotein cholesterol ratio (TG/HDL-c) is crucial when researching metabolic and vascular diseases, and its involvement in COVID-19 was sparsely elaborated on. The purpose of the study was to explore the inflammatory associations between the TG/HDL-c ratio and COVID-19 prognosis.

Methods

A total of 262 COVID-19 patients consisting of 244 survivors and 18 non-survivors were retrospectively investigated. The clinical features and baseline hematological parameters were recorded and analyzed. The receiver operating characteristic curve (ROC) was used to explore the role of TG/HDL-c in predicting the mortality of COVID-19, the Spearman’s rank correlation coefficients were used to measure the correlation between TG/HDL-c and inflammatory indicators, and the Kaplan–Meier (KM) curve was used to estimate the survival of COVID-19 patients with high and low TG/HDL-c ratio. Logistic regression analyses were performed to investigate the role of TG/HDL-c ratio on mortality of COVID-19 with no underlying diseases.

Results

Compared with the survivors, the non-survivors of COVID-19 had significantly higher levels of white blood cells (4.7 vs 13.0 × 10⁹/L; P < 0.001), neutrophils (3.0 vs 11.6 × 10⁹/L; P < 0.001), C-reactive proteins (15.7 vs 76.7 mg/L; P < 0.001) and TG/HDL-c ratio (1.4 vs 2.5; P = 0.001). The ROC curve [area under the curve (AUC), 0.731; 95% confidence interval (CI), 0.609–0.853; P = 0.001] suggested that the TG/HDL-c ratio could predict the mortality of COVID-19. The TG/HDL-c ratio was positively correlated with white blood cells (r = 0.255, P < 0.001), neutrophils (r = 0.243, P < 0.001) and C-reactive proteins (r = 0.170, P < 0.006). Patients with high TG/HDL-c ratio showed a worse survival compared with those with low TG/HDL-c ratio (Log rank P = 0.003). Moreover, TG/HDL-c ratio was an independent factor in predicting the mortality of COVID-19 patients with no underlying diseases.

Conclusion

Our study demonstrated that TG/HDL-c ratio might potentially be a predictive marker for mortality in COVID-19 patients.

Lipidome association with vascular disease and inflammation in HIV+ Ugandan children

OBJECTIVE

HIV infection and antiretroviral therapy (ART) have both been linked to dyslipidemia and increased cardiovascular disease (CVD). The relationships among the lipidome, immune activation, and subclinical vascular disease in children with perinatally acquired HIV (PHIV) have not been investigated.

METHODS

Serum lipid composition, including 13 lipid classes constituting 850 different lipid species were measured by direct infusion-tandem mass spectrometry in samples from 20 ART-treated PHIV and 20 age-matched and sex-matched HIV- Ugandan children. All participants were between 10 and 18 years of age with no other known active infections. PHIVs had HIV-1 RNA level 50 copies/ml or less. In addition, common carotid artery intima--media thickness (IMT), as well as plasma marker of systemic inflammation (hsCRP, IL6, sTNFRa I), monocyte activation (soluble CD14 and CD163), and T-cell activation (expression of CD38 and HLA-DR on CD4+ and CD8+) were evaluated.

RESULTS

Median age (Q1, Q3) of study participants was 13 years (11, 15), 37% were boys, 75% were on an NNRTI-based ART regimen. The concentrations of cholesterol ester, LCER, phosphatidylcholines, and sphingomyelin lipid classes were significantly increased in serum of PHIV compared with HIV (P≤0.04). Biomarkers associated with CVD risk including hsCRP, sCD163, and T-cell activation were directly correlated with lipid species in PHIV (P ≤ 0.04). Contents of free fatty acids including palmitic (16 : 0), stearic (18 : 0), and arachidic acid (20 : 0) were positively correlated with IMT in PHIV.

CONCLUSION

Serum lipidome is altered in young virally suppressed PHIV on ART. A direct association between inflammation and lipid species known to be associated with CVD was observed.

The Role of High-Density Lipoprotein in COVID-19

The current Coronavirus disease 2019 (COVID-19) pandemic has become a global challenge. Managing a large number of acutely ill patients in a short time, whilst reducing the fatality rate and dealing with complications, brings unique difficulties. The most striking pathophysiological features of patients with severe COVID-19 are dysregulated immune responses and abnormal coagulation function, which can result in multiple-organ failure and death. Normally metabolized high-density lipoprotein (HDL) performs several functions, including reverse cholesterol transport, direct binding to lipopolysaccharide (LPS) to neutralize LPS activity, regulation of inflammatory response, anti-thrombotic effects, antioxidant, and anti-apoptotic properties. Clinical data shows that significantly decreased HDL levels in patients with COVID-19 are correlated with both disease severity and mortality. However, the role of HDL in COVID-19 and its specific mechanism remain unclear. In this analysis, we review current evidence mainly in the following areas: firstly, the pathophysiological characteristics of COVID-19, secondly, the pleiotropic properties of HDL, thirdly, the changes and clinical significance of HDL in COVID-19, and fourthly the prospect of HDL-targeting therapy in COVID-19 to clarify the role of HDL in the pathogenesis of COVID-19 and discuss the potential of HDL therapy in COVID-19.

Hepatic Steatosis and Ectopic Fat Are Associated With Differences in Subcutaneous Adipose Tissue Gene Expression in People With HIV

Persons with human immunodeficiency virus (PWH) have subcutaneous adipose tissue (SAT) dysfunction related to antiretroviral therapy and direct viral effects, which may contribute to a higher risk of nonalcoholic fatty liver disease compared with human immunodeficiency virus-negative individuals. We assessed relationships between SAT expression of major adipocyte regulatory and lipid storage genes with hepatic and other ectopic lipid deposits in PWH. We enrolled 97 PWH on long-term antiretroviral therapy with suppressed plasma viremia and performed computed tomography measurements of liver attenuation, a measure of hepatic steatosis, skeletal muscle (SM) attenuation, and the volume of abdominal subcutaneous, visceral, and pericardial adipose tissue. Whole SAT gene expression was measured using the Nanostring platform, and relationships with computed tomography imaging and fasting lipids were assessed using multivariable linear regression and network mapping. The cohort had a mean age of 47 years, body mass index of 33.4 kg/m2, and CD4 count of 492 cells/mm3. Lower liver attenuation, a marker of greater steatosis, was associated with differences in SAT gene expression, including lower lipoprotein lipase and acyl-CoA dehydrogenase, and higher phospholipid transfer protein. Lower liver attenuation clustered with lower visceral adipose tissue (VAT) attenuation and greater VAT volume, pericardial fat volume and triglycerides, but no relationship was observed between liver attenuation and SAT volume, SM attenuation, or low-density lipoprotein. Conclusion: Liver attenuation was associated with altered SAT expression of genes regulating lipid metabolism and storage, suggesting that SAT dysfunction may contribute to nonalcoholic fatty liver disease in PWH. SAT gene-expression relationships were similar for VAT volume and attenuation, but not SM, indicating that ectopic lipid deposition may involve multiple pathways.

Multifaced Roles of HDL in Sepsis and SARS-CoV-2 Infection: Renal Implications

High-density lipoproteins (HDLs) are a class of blood particles, principally involved in mediating reverse cholesterol transport from peripheral tissue to liver. Omics approaches have identified crucial mediators in the HDL proteomic and lipidomic profile, which are involved in distinct pleiotropic functions. Besides their role as cholesterol transporter, HDLs display anti-inflammatory, anti-apoptotic, anti-thrombotic, and anti-infection properties. Experimental and clinical studies have unveiled significant changes in both HDL serum amount and composition that lead to dysregulated host immune response and endothelial dysfunction in the course of sepsis. Most SARS-Coronavirus-2-infected patients admitted to the intensive care unit showed common features of sepsis disease, such as the overwhelmed systemic inflammatory response and the alterations in serum lipid profile. Despite relevant advances, episodes of mild to moderate acute kidney injury (AKI), occurring during systemic inflammatory diseases, are associated with long-term complications, and high risk of mortality. The multi-faceted relationship of kidney dysfunction with dyslipidemia and inflammation encourages to deepen the clarification of the mechanisms connecting these elements. This review analyzes the multifaced roles of HDL in inflammatory diseases, the renal involvement in lipid metabolism, and the novel potential HDL-based therapies.

Interaction of amphiphilic lipoarabinomannan with host carrier lipoproteins in tuberculosis patients: Implications for blood-based diagnostics

Lipoarabinomannan (LAM), an amphiphilic lipoglycan of the Mycobacterium tuberculosis cell wall, is a diagnostic target for tuberculosis. Previous work from our laboratory and others suggests that LAM is associated with host serum lipoproteins, which may in turn have implications for diagnostic assays. Our team has developed two serum assays for amphiphile detection: lipoprotein capture and membrane insertion. The lipoprotein capture assay relies on capture of the host lipoproteins, exploiting the biological association of host lipoprotein with microbial amphiphilic biomarkers to "concentrate" LAM. In contrast, the membrane insertion assay is independent of the association between pathogen amphiphiles and host lipoprotein association, and directly captures LAM based on its thermodynamic propensity for association with a supported lipid membrane, which forms the functional surface of an optical biosensor. In this manuscript, we explored the use of these assays for the detection of LAM in sera from adults whose tuberculosis status had been well-characterized using conventional microbiological tests, and endemic controls. Using the lipoprotein capture assay, LAM signal/noise ratios were >1.0 in 29/35 (83%) individuals with culture-confirmed active tuberculosis, 8/13 (62%) individuals with tuberculosis symptoms, but no positive culture for M. tuberculosis, and 0/6 (0%) symptom-free endemic controls. To evaluate serum LAM levels without bias associated with potential differences in circulating host lipoprotein concentrations between individuals, we subsequently processed available samples to liberate LAM from associated host lipoprotein assemblies followed by direct detection of the pathogen biomarker using the membrane insertion approach. Using the membrane insertion assay, signal/noise for detection of serum LAM was greater than that observed using the lipoprotein capture method for culture-confirmed TB patients (6/6), yet remained negative for controls (2/2). Taken together, these results suggest that detection of serum LAM is a promising TB diagnostic approach, but that further work is required to optimize assay performance and to decipher the implications of LAM/host lipoprotein associations for diagnostic assay performance and TB pathogenesis.

The Role of the ATP-Binding Cassette A1 (ABCA1) in Human Disease

Cholesterol homeostasis is essential in normal physiology of all cells. One of several proteins involved in cholesterol homeostasis is the ATP-binding cassette transporter A1 (ABCA1), a transmembrane protein widely expressed in many tissues. One of its main functions is the efflux of intracellular free cholesterol and phospholipids across the plasma membrane to combine with apolipoproteins, mainly apolipoprotein A-I (Apo A-I), forming nascent high-density lipoprotein-cholesterol (HDL-C) particles, the first step of reverse cholesterol transport (RCT). In addition, ABCA1 regulates cholesterol and phospholipid content in the plasma membrane affecting lipid rafts, microparticle (MP) formation and cell signaling. Thus, it is not surprising that impaired ABCA1 function and altered cholesterol homeostasis may affect many different organs and is involved in the pathophysiology of a broad array of diseases. This review describes evidence obtained from animal models, human studies and genetic variation explaining how ABCA1 is involved in dyslipidemia, coronary heart disease (CHD), type 2 diabetes (T2D), thrombosis, neurological disorders, age-related macular degeneration (AMD), glaucoma, viral infections and in cancer progression.

Evolution of blood lipids and risk factors of dyslipidemia among people living with human immunodeficiency virus who had received first-line antiretroviral regimens for 3 years in Shenzhen

BACKGROUND

Lipid abnormalities are prevalent among people living with human immunodeficiency virus (HIV) (PLWH) and contribute to increasing risk of cardiovascular events. This study aims to investigate the incidence of dyslipidemia and its risk factors in PLWH after receiving different first-line free antiretroviral regimens.

METHODS

PLWH who sought care at the Third People's Hospital of Shenzhen from January 2014 to December 2018 were included, and the baseline characteristics and clinical data during the follow-up were collected, including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). The risk factors of dyslipidemia after antiretroviral therapy were analyzed with the generalized estimating equation model.

RESULTS

Among the 7623 PLWH included, the mean levels of TC, HDL-C and LDL-C were 4.23 ± 0.85 mmol/L, 1.27 ± 0.29 mmol/L and 2.54 ± 0.65 mmol/L, respectively, and the median TG was 1.17 (IQR: 0.85-1.68) mmol/L. Compared with that in PLWH receiving tenofovir disoproxil fumarate (TDF) + lamivudine (3TC) + ritonavir-boosted lopinavir (LPV/r), zidovudine (AZT) + 3TC + efavirenz (EFV), and AZT + 3TC + LPV/r, the incidence of dyslipidemia was lower in PLWH receiving TDF + 3TC + EFV. In multivariate analysis, we found that the risks of elevations of TG, TC, and LDL-C were higher with TDF + 3TC + LPV/r (TG: odds ratio [OR] = 2.82, 95% confidence interval [CI]: 2.55-3.11, P < 0.001; TC: OR = 1.24, 95% CI: 1.14-1.35, P < 0.001; LDL: OR = 1.06, 95% CI: 1.00-1.12, P = 0.041), AZT + 3TC + EFV (TG: OR = 1.41, 95% CI: 1.28-1.55, P < 0.001; TC: OR = 1.43, 95% CI: 1.31-1.56, P < 0.001; LDL: OR = 1.18, 95% CI: 1.12-1.25, P < 0.001), and AZT + 3TC + LPV/r (TG: OR = 3.08, 95% CI: 2.65-3.59, P < 0.001; TC: OR = 2.40, 95% CI: 1.96-2.94, P < 0.001; LDL: OR = 1.52, 95% CI: 1.37-1.69, P < 0.001) than with TDF + 3TC + EFV, while treatment with TDF + 3TC + LPV/r was less likely to restore HDL-C levels compared with TDF + 3TC + EFV (OR = 0.95, 95% CI: 0.92-0.97, P < 0.001). In addition to antiretroviral regimens, antiretroviral therapy duration, older age, overweight, obesity and other traditional factors were also important risk factors for dyslipidemia.

CONCLUSION

The incidence of dyslipidemia varies with different antiretroviral regimens, with TDF + 3TC + EFV having lower risk for dyslipidemia than the other first-line free antiretroviral regimens in China.

Cross-talk between lipid homeostasis and endoplasmic reticulum stress in neurodegeneration: Insights for HIV-1 associated neurocognitive disorders (HAND)

The dysregulation of lipid homeostasis is emerging as a hallmark of many CNS diseases. As aberrant protein regulation is suggested to be a shared pathological feature amongst many neurodegenerative conditions, such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD), disruptions in neuronal lipid processing may contribute to disease progression in the CNS. Specifically, given the endoplasmic reticulum (ER) dual role in lipid homeostasis as well as protein quality control (PQC) via unfolded protein response (UPR), lipid dysregulation in the CNS may converge on ER functioning and constitute a crucial mechanism underlying aberrant protein aggregation. In the current review, we discuss the diverse roles of lipid species as essential components of the CNS. Moreover, given the importance of both lipid dysregulation and protein aggregation in pathology of CNS diseases, we attempt to assess the potential downstream cross-talk between lipid dysregulation and ER dependent PQC mechanisms, with special focus on HIV-associated neurodegenerative disorders (HAND).

HIV-related cardiovascular disease: any role for high-density lipoproteins?

The introduction of antiretroviral therapy (ART) has improved the life expectancy of patients infected with human immunodeficiency virus (HIV). However, this population is at an increased risk for noncommunicable diseases, including atherosclerotic cardiovascular disease (CVD). Both ART and viral infection may be potential contributors to the pathophysiology of HIV-related CVD. The mechanisms behind this remain unclear, but it is critical to delineate early biomarkers of cardiovascular risk in the HIV population. In this review, we postulate that potential biomarkers could include alterations to high-density lipoprotein (HDL). Indeed, recent data suggest that HIV and ART may induce structural changes of HDL, thus resulting in shifts in HDL subclass distribution and HDL functionality.

Lipoprotein concentrations over time in the intensive care unit COVID-19 patients: Results from the ApoCOVID study

INTRODUCTION

Severe acute respiratory syndrome coronavirus2 has caused a global pandemic of coronavirus disease 2019 (COVID-19). High-density lipoproteins (HDLs), particles chiefly known for their reverse cholesterol transport function, also display pleiotropic properties, including anti-inflammatory or antioxidant functions. HDLs and low-density lipoproteins (LDLs) can neutralize lipopolysaccharides and increase bacterial clearance. HDL cholesterol (HDL-C) and LDL cholesterol (LDL-C) decrease during bacterial sepsis, and an association has been reported between low lipoprotein levels and poor patient outcomes. The goal of this study was to characterize the lipoprotein profiles of severe ICU patients hospitalized for COVID-19 pneumonia and to assess their changes during bacterial ventilator-associated pneumonia (VAP) superinfection.

METHODS

A prospective study was conducted in a university hospital ICU. All consecutive patients admitted for COVID-19 pneumonia were included. Lipoprotein levels were assessed at admission and daily thereafter. The assessed outcomes were survival at 28 days and the incidence of VAP.

RESULTS

A total of 48 patients were included. Upon admission, lipoprotein concentrations were low, typically under the reference values ([HDL-C] = 0.7[0.5-0.9] mmol/L; [LDL-C] = 1.8[1.3-2.3] mmol/L). A statistically significant increase in HDL-C and LDL-C over time during the ICU stay was found. There was no relationship between HDL-C and LDL-C concentrations and mortality on day 28 (log-rank p = 0.554 and p = 0.083, respectively). A comparison of alive and dead patients on day 28 did not reveal any differences in HDL-C and LDL-C concentrations over time. Bacterial VAP was frequent (64%). An association was observed between HDL-C and LDL-C concentrations on the day of the first VAP diagnosis and mortality ([HDL-C] = 0.6[0.5-0.9] mmol/L in survivors vs. [HDL-C] = 0.5[0.3-0.6] mmol/L in nonsurvivors, p = 0.036; [LDL-C] = 2.2[1.9-3.0] mmol/L in survivors vs. [LDL-C] = 1.3[0.9-2.0] mmol/L in nonsurvivors, p = 0.006).

CONCLUSION

HDL-C and LDL-C concentrations upon ICU admission are low in severe COVID-19 pneumonia patients but are not associated with poor outcomes. However, low lipoprotein concentrations in the case of bacterial superinfection during ICU hospitalization are associated with mortality, which reinforces the potential role of these particles during bacterial sepsis.

Cholesterol: A new game player accelerating vasculopathy caused by SARS-CoV-2?

The pandemic of coronavirus disease (COVID-19) has become a global threat to public health. Functional impairments in multiple organs have been reported in COVID-19, including lungs, heart, kidney, liver, brain, and vascular system. Patients with metabolic-associated preconditions, such as hypertension, obesity, and diabetes, are susceptible to experiencing severe symptoms. The recent emerging evidence of coagulation disorders in COVID-19 suggests that vasculopathy appears to be an independent risk factor promoting disease severity and mortality of affected patients. We recently found that the decreased levels of low-density lipoprotein cholesterols (LDL-c) correlate with disease severity in COVID-19 patients, indicating pathological interactions between dyslipidemia and vasculopothy in patients with COVID-19. However, this clinical manifestation has been unintentionally underestimated by physicians and scientific communities. As metabolic-associated morbidities are generally accompanied with endothelial cell (EC) dysfunctions, these pre-existing conditions may make ECs more vulnerable to SARS-CoV-2 attack. In this mini-review, we summarize the metabolic and vascular manifestations of COVID-19 with an emphasis on the association between changes in LDL-c levels and the development of severe symptoms as well as the pathophysiologic mechanisms underlying the synergistic effect of LDL-c and SARS-CoV-2 on EC injuries and vasculopathy.

Hypolipidemia is associated with the severity of COVID-19

Background

Many patients with coronavirus disease 2019 (COVID-19) suffer multiple organ dysfunctions. However, whether patients develop dyslipidemia is unknown.

Objective

In this study, we aimed to investigate the pathological alterations of low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), and total cholesterol (TC) in COVID-19 patients and their relationships with the disease severity.

Methods

A retrospective study was performed to examine serum levels of LDL-c, HDL-c, and TC on 597 COVID-19 patients (mild: 394; severe, 171; critical: 32) who were hospitalized in our center between February 1 and March 3, 2020. Age- and gender-matched normal subjects (n = 50) who had routine laboratory lipid tests between October 1 and November 1, 2019 in our center were included as the control group.

Results

LDL-c and TC levels were significantly lower in COVID-19 patients as compared with normal subjects (P < .001). There were significant and gradual decreases in levels of LDL-c (median (IQR) in mg/dL, mild: 91 (76, 104); severe: 86 (69, 102); critical: 69 (48, 81); P < .02) and TC (mild: 173 (148, 203); severe: 167 (138, 197); critical: 125 (95, 162); P < .05) across all three groups. HDL-c levels only decreased significantly in critical cases as compared with levels in mild and severe cases. LDL-c and TC levels inversely correlated with C-reactive protein and interleukin-6, and positively correlated with the number of lymphocytes in patients.

Conclusions

Development of hypolipidemia begins in patients with mild symptoms. It progressively becomes worse in an association with the disease severity.

•

SARS-COV-2 causes multiple types of pathophysiologies including hypolipidemia.

•

Decrease in LDL-c is observed as early as in patients with mild symptoms.

•

Hypolipidemia positively correlates with the disease severity in patients.

•

Hypolipidemia raises awareness to frontline physicians against this pandemic.

Lipidome Abnormalities and Cardiovascular Disease Risk in HIV Infection

PURPOSE OF REVIEW

Human immunodeficiency virus (HIV) infection and its treatment with antiretroviral therapy (ART) are associated with lipid abnormalities that may enhance cardiovascular disease risk (CVD).

RECENT FINDINGS

Chronic inflammation persists in HIV+ individuals, and complex relationships exist among lipids and inflammation, as immune activation may be both a cause and a consequence of lipid abnormalities in HIV infection. Advances in mass spectrometry-based techniques now allow for detailed measurements of individual lipid species; improved lipid measurement might better evaluate CVD risk compared with the prognostic value of traditional assessments. Lipidomic analyses have begun to characterize dynamic changes in lipid composition during HIV infection and following treatment with ART, and further investigation may identify novel lipid biomarkers predictive of adverse outcomes. Developing strategies to improve management of comorbidities in the HIV+ population is important, and statin therapy and lifestyle modifications, including diet and exercise, may help to improve lipid levels and mitigate CVD risk.

Comparison of calculated versus directly-measured low-density lipoprotein-cholesterol: An evaluation of ten formulas for an HIV-positive population in Sub-Saharan Africa

BACKGROUND:

Low-density lipoprotein cholesterol (LDLC) is a modifiable risk factor for atherosclerotic cardiovascular disease, therefore needs to be assessed and monitored. Direct homogeneous assays and various formulas exist to determine LDLC. We aimed to compare the directly measured LDL (dLDLC) with ten formulas for estimating LDLC.

MATERIALS AND METHODS:

This was a 2-year retrospective study of fasting lipid profile results obtained from HIV-positive patients attending an outpatient clinic at the University of Nigeria Teaching Hospital, Enugu, Nigeria, using homogeneous direct assays. Estimated LDLC was determined using ten formulas. Pearson's correlation, Bland–Altman plots, and linear regression were performed. Statistical significance was P < 0.05.

RESULTS:

Three thousand four hundred and eighty-two lipid results with mean ± standard deviation (SD) dLDLC of 2.1 ± 1.1 mmol/L were included in this study. There was a strong, positive correlation between Friedewald's LDLC and dLDLC n = 3412, r = 0.84, P < 0.001, but linear regression demonstrated a proportional bias P = 0.005. Ahmadi's equation showed the worst correlation n = 3482, r = 0.35, P < 0.001, but when applied to samples with triglyceride (TG) <1.13 mmol/L (100 mg/dl), the correlation showed a strong, positive relationship n = 1395, r = 0.80, P < 0.001, and no proportional bias P = 0.86. Teerankanchana's equation was the only formula that showed no difference between its LDLC and dLDLC (n = 3482, P = 0.056). It also demonstrated strong, positive correlation (n = 3482, r = 0.84, P < 0.001) and had a mean difference ± SD of −0.68 ± 0.63.

CONCLUSION:

Teerankanchana's formula showed good correlation and minimal bias with dLDLC at all TG levels. Moreover, linear regression showed no difference in the two. It seems to be the most suitable formula for estimating LDLC in our HIV-positive population.

Metabolic Syndrome in HIV/HCV Co-infected Patients

Purpose of review

We review the scope and burden of metabolic syndrome in HIV/HCV co-infected patients, risk factors and potential mechanisms driving the increased cardio-metabolic risk in this population, and discuss relevant clinical considerations for management in the era of highly effective antiretroviral therapy (ART) and curative anti-HCV direct-acting antivirals.

Recent findings

HIV/HCV co-infected patients are at elevated risk of metabolic syndrome, attributed to (1) patient-specific factors, (2) viral-mediated effects, and (3) ART exposure. Risk factors for cardio-metabolic disorders are common in this population and include poor socioeconomic conditions, substance use, cardiovascular comorbidities, and liver/kidney disease. Chronic HIV/HCV infection induces an inflammatory and immune activated state in the host leading to alterations in glucose and lipid metabolism. Selection of life-saving ART must carefully consider the differential metabolic risk associated with each drug class and agent, such as dyslipidemia, hyperglycemia and insulin resistance, weight gain and hypertension. Emerging evidence supports metabolic derangements in chronic HCV may be improved by viral eradication with direct-acting antivirals, however, additional study in HIV/HCV co-infected patients is needed.

Summary

Future research programs should aim to better characterize metabolic syndrome in HIV/HCV co-infected patients with the goal of improved screening, treatment and prevention.

Atherosclerotic Cardiovascular Disease Risk Profile of Tenofovir Alafenamide Versus Tenofovir Disoproxil Fumarate

Background

In human immunodeficiency virus (HIV) treatment, tenofovir alafenamide (TAF) is associated with greater increases in all fasting cholesterol subgroups compared with tenofovir disoproxil fumarate (TDF). Because lipid abnormalities may contribute to cardiovascular morbidity and mortality, cardiovascular risk assessment is integral to routine HIV care. This post hoc study evaluates the impact of lipid changes on predicted atherosclerotic cardiovascular disease (ASCVD) risk and statin eligibility in treatment-naive adults living with HIV treated with TAF or TDF.

Methods

Participants (N = 1744) were randomized (1:1) to initiate TAF or TDF, each coformulated with elvitegravir/cobicistat/emtricitabine (studies GS-US-292-0104 and GS-US-292-0111). Eligibility for statin therapy and estimated 10-year ASCVD risk among adults aged 40–79 years treated with TAF or TDF for 96 weeks (W96) were analyzed based on American College of Cardiology/American Heart Association Pooled Cohort Equations. Categorical shifts in 10-year ASCVD risk from <7.5% to ≥7.5% by W96 on TAF versus TDF were calculated.

Results

Participants initiating TAF versus TDF in the overall study population showed small but significant increases in median fasting lipid parameters at W96, including total cholesterol (191 vs 177 mg/dL; P < .001), low-density lipoprotein ([LDL] 119 vs 112 mg/dL; P < .001), and high-density lipoprotein ([HDL] 51 vs 48 mg/dL; P < .001), respectively. At baseline, 18% and 23% on TAF versus TDF had a 10-year ASCVD risk score ≥7.5%, with mean risk scores low overall for TAF versus TDF at baseline (4.9% vs 5.4%; P = .35) and W96 (6.1% vs 6.2%; P = .04). Increases in ASCVD risk from baseline to W96 were driven by both increasing age and changes in total cholesterol (TC) and HDL cholesterol. At W96, TC/HDL ratios (median) were 3.7 for both groups (P = .69). There was no difference between shifts in categorical risk for TAF versus TDF (9% vs 5%; P = .19). Eligibility for high-intensity statin therapy were similar for TAF versus TDF groups (19% vs 21%; P = .47).

Conclusions

Lipid changes with TAF as part of coformulated regimens do not substantively affect CVD risk profiles compared with TDF.

HIV disease, metabolic dysfunction and atherosclerosis: A three year prospective study

HIV infection is known to be associated with cardiometabolic abnormalities; here we investigated the progression and causes of these abnormalities. Three groups of participants were recruited: HIV-negative subjects and two groups of treatment-naïve HIV-positive subjects, one group initiating antiretroviral treatment, the other remaining untreated. Intima-media thickness (cIMT) increased in HIV-positive untreated group compared to HIV-negative group, but treatment mitigated the difference. We found no increase in diabetes-related metabolic markers or in the level of inflammation in any of the groups. Total cholesterol, low density lipoprotein cholesterol and apoB levels were lower in HIV-positive groups, while triglyceride and Lp(a) levels did not differ between the groups. We found a statistically significant negative association between viral load and plasma levels of total cholesterol, LDL cholesterol, HDL cholesterol, apoA-I and apoB. HIV-positive patients had hypoalphalipoproteinemia at baseline, and we found a redistribution of sub-populations of high density lipoprotein (HDL) particles with increased proportion of smaller HDL in HIV-positive untreated patients, which may result from increased levels of plasma cholesteryl ester transfer protein in this group. HDL functionality declined in the HIV-negative and HIV-positive untreated groups, but not in HIV-positive treated group. We also found differences between HIV-positive and negative groups in plasma abundance of several microRNAs involved in lipid metabolism. Our data support a hypothesis that cardiometabolic abnormalities in HIV infection are caused by HIV and that antiretroviral treatment itself does not influence key cardiometabolic parameters, but mitigates those affected by HIV.

Von Willebrand Factor Adhesive Activity and ADAMTS13 Protease Activity in HIV-1-Infected Men

Background: Endothelial activation caused by HIV-1 infection leads to release of von Willebrand factor (VWF), which enters the circulation or attaches to vessel walls and self-assembles into strings and fibers, enabling platelet adhesion; this adhesive activity is regulated by the VWF-cleaving protease ADAMTS13. Our objective was to assess VWF adhesive activity and ADAMTS13 protease activity in HIV-1 infection. Methods: We measured levels of VWF antigen, VWF activation factor (a measure of adhesive activity), ADAMTS13 antigen, ADAMTS13 activity, and apolipoprotein A1 (which interferes with VWF self-association) in serum samples from HIV-1-infected men whose infections were acute (n=10), chronic untreated (n=10), or chronic treated (n=10), compared to uninfected controls (n=10). Means across groups were compared using analysis of variance with contrasts, and Pearson correlations were calculated. Results: Plasma viral load was positively correlated with VWF adhesive activity, which was elevated in acute relative to chronic treated HIV-1 infection. ADAMTS13 antigen and activity were both positively correlated with plasma viral load, and ADAMTS13 activity was significantly higher in men with acute HIV infection than in uninfected controls, and in both acute and chronic untreated HIV infection relative to chronic treated infection. Conclusion: These findings suggest that even in the setting of increased ADAMTS13 protease activity, VWF in HIV-1 infection is hyperadhesive, which may favor development of microvascular and arterial thromboses and thereby contribute to increased cardiovascular risk in HIV-1-infected individuals.

Apolipoprotein E is an HIV-1-inducible inhibitor of viral production and infectivity in macrophages

Apolipoprotein E (ApoE) belongs to a class of cellular proteins involved in lipid metabolism. ApoE is a polymorphic protein produced primarily in macrophages and astrocytes. Different isoforms of ApoE have been associated with susceptibility to various diseases including Alzheimer's and cardiovascular diseases. ApoE expression has also been found to affect susceptibility to several viral diseases, including Hepatitis C and E, but its effect on the life cycle of HIV-1 remains obscure. In this study, we initially found that HIV-1 infection selectively up-regulated ApoE in human monocyte-derived macrophages (MDMs). Interestingly, ApoE knockdown in MDMs enhanced the production and infectivity of HIV-1, and was associated with increased localization of viral envelope (Env) proteins to the cell surface. Consistent with this, ApoE over-expression in 293T cells suppressed Env expression and viral infectivity, which was also observed with HIV-2 Env, but not with VSV-G Env. Mechanistic studies revealed that the C-terminal region of ApoE was required for its inhibitory effect on HIV-1 Env expression. Moreover, we found that ApoE and Env co-localized in the cells, and ApoE associated with gp160, the precursor form of Env, and that the suppression of Env expression by ApoE was cancelled by the treatment with lysosomal inhibitors. Overall, our study revealed that ApoE is an HIV-1-inducible inhibitor of viral production and infectivity in macrophages that exerts its anti-HIV-1 activity through association with gp160 Env via the C-terminal region, which results in subsequent degradation of gp160 Env in the lysosomes.

Serum ghrelin and obestatin levels in HIV-infected patients: Effect of 36 weeks of antiretroviral treatment

INTRODUCTION

Patients with HIV+ often present lipid disturbances. The role of ghrelin and obestatin in these lipid disturbances is not clear. The effect of antiretroviral (ART) drugs on those molecules is also unknown. This study measured ghrelin and obestatin levels, as well as metabolic markers, in patients with HIV+ before and after 36 weeks of ART.

MATERIAL AND METHODS

Twenty HIV-positive, ART-naïve patients who started a scheme consisting of tenofovir/emtricitabine+lopinavir/ritonavir were enrolled. Plasma samples were collected before and after 36 weeks of treatment. Serum ghrelin and obestatin levels were quantitated by ELISA; glucose, cholesterol, and triglyceride levels were measured by colorimetric and enzymatic methods, and cardiovascular risk was calculated by the atherogenic index of plasma (AIP).

RESULTS

All patients completed 36 weeks of ART. Total cholesterol (p<0.001), LDL-C (p=0.019), HDL-C (p=0.003), VLDL-C (p=0.002), and triglyceride levels (p=0.021) significantly increased after treatment. AIP revealed increased cardiovascular risk at baseline, which remained high after treatment. There was a statistically significant increase in obestatin level in the unpaired and paired analyses, while ghrelin levels only showed a trend to increase. Changes in ghrelin and obestatin levels positively correlated, but no correlation was seen with any metabolic parameter.

CONCLUSION

After 36 weeks of ART, patients showed an altered lipid profile, but there were no significant changes in cardiovascular risk. Ghrelin and obestatin levels increased after 36 weeks of ART, but the increase was only significant for obestatin. Changes in ghrelin and obestatin positively correlate.

Cholesterol efflux responds to viral load and CD4 counts in HIV+ patients and is dampened in HIV exposed

Cholesterol efflux (CE) capacity has been inversely associated with atherosclerosis and may provide an insight on inflammation occurring in human immunodeficiency virus (HIV) individuals. We address this by studying CE in HIV patients at different stages of HIV disease progression. In this cross-sectional study, CE from ApoB-depleted plasma, lipids levels, viral load (VL), CD4+/CD8+ T-cells, high-sensitive C-reactive protein (hsCRP), and lipoprotein (a) were evaluated in untreated HIV-infected patients (UHIVs; n = 43), elite controllers (ECs; n = 8), HIV-exposed seronegative individuals (HESNs; n = 32), and healthy controls (HCs; n = 14). Among UHIVs, those with CD4+ <500 cells/mm³ presented the lowest significant CE, HDL cholesterol (HDL-C), and ApoAI levels. ECs showed similar HDL-C, ApoAI, and CE compared with HCs. Among UHIVs, CE positively correlated with CD4+ T-cell counts (Beta: 1.05; 95% CI: 1.02; 1.07), and for VL higher than 3.8 log, CE was inversely associated with VL (Beta: 0.70; 95% CI: 0.51; 0.95). Remarkably, HESNs presented higher CE (0.78 ± 0.14) than UHIVs (0.65 ± 0.17; P = 0.0005), but lower than HCs (0.90 ± 0.13; P = 0.009). hsCRP levels were highest in the UHIV group (0.45 ± 0.49). CE was sensitive to HIV disease progression. Low CE in HIV patients was associated with lower CD4+ T-cells and higher VL and hsCRP. CE was also lower in HESNs compared with HCs. Our results suggest that immune status secondary to HIV progression and exposure influence plasma HDL-CE capacity.

Atherosclerosis in subjects newly diagnosed with human immunodeficiency virus infection

HIV infection is associated with the increased risk of cardiovascular disease (CVD), even in patients successfully treated with the combination antiretroviral therapy (cART). However, the relationship between HIV, cART, and pathogenesis of CVD remains controversial. In the present study, we evaluated the carotid intima-media thickness (CIMT), a surrogate marker of atherosclerosis, in HIV-infected subjects receiving or not receiving cART. One hundred nine newly diagnosed HIV-infected subjects and one hundred nine uninfected age-matched controls (all males) without the history of CVD, hypertension, or diabetes were recruited into the present study. Cross-sectional analysis at baseline (BL) showed significantly increased levels of triglycerides (TG) and decreased levels of high-density lipoprotein (HDL) in HIV-infected subjects, indicating that these risk factors for CVD appeared during the undiagnosed period of HIV infection. Nevertheless, no differences in CIMT were detected between the groups, suggesting that these risk factors were yet to be translated into the clinical disease. The prospective arm of the study, which included 37 HIV-infected and 23 uninfected subjects, showed higher CIMT increase in HIV-infected group than in control group (P=0.0063). This difference was significant for both cART-treated (P=0.0066) and untreated (P=0.0246) subgroups relative to the uninfected subjects, but no difference was found between the HIV-infected subgroups. These results suggest that cART does not reverse the HIV-induced increase of CIMT. The present study demonstrates that the progression of atherosclerosis is accelerated in HIV-infected subjects regardless of treatment.

Evaluation of inflammatory biomarkers, carotid intima-media thickness and cardiovascular risk in HIV-1 treatment-naive patients

INTRODUCTION

Mortality among HIV patients is 3-15 times higher than that among the general population. Currently, most deaths are due to non-infectious diseases. Chronic inflammation and adverse events due to antiretroviral therapy play crucial roles in increasing cardiovascular risk (CVR).

METHODS

This cross-sectional study aimed to evaluate carotid intima-media thickness (CIMT) and inflammatory biomarkers (D-dimer, ADAMTS13, GDF-15, sICAM-1, MPO, myoglobin, NGAL, SAA, sVCAM-1, and p-selectin) among naïve patients.

RESULTS

Sixty-seven participants were included: median age, 32 years; males, 82.1%; non-white, 61.1%; higher education level, 62.7%; and exposed to HIV through sexual relationship (men who have sex with men), 68.7%. The median viral load and LTCD4+ value were 42,033 copies/mL and 426 cells/mm³. The prevalence of arterial hypertension was 16.4%; those of diabetes mellitus and dyslipidemia were 3% and 70.1%, respectively. The CIMT was 494.08 (± 96.84mm). The mean vascular age was 33.2 ± 18.9 years, one year longer than the chronological age, without statistical significance.

CONCLUSIONS

The majority of participants had a low CVR (94%). After reclassification, considering the CIMT percentiles, 13 (19.4%) patients had medium/ high CVR, while 54 (80.6%) patients had low CVR. The difference between the proportions of CVR when considering the CIMT and its corresponding percentile was statistically relevant. Body mass index was the only predictor of higher CVR (p = 0.03). No biomarker was found to predict CVR. People living with HIV have a high prevalence of dyslipidemia before ARV therapy.

A baseline metabolomic signature is associated with immunological CD4+ T-cell recovery after 36 months of antiretroviral therapy in HIV-infected patients

Objectives:

Poor immunological recovery in treated HIV-infected patients is associated with greater morbidity and mortality. To date, predictive biomarkers of this incomplete immune reconstitution have not been established. We aimed to identify a baseline metabolomic signature associated with a poor immunological recovery after antiretroviral therapy (ART) to envisage the underlying mechanistic pathways that influence the treatment response.

Design:

This was a multicentre, prospective cohort study in ART-naive and a pre-ART low nadir (<200 cells/μl) HIV-infected patients (n = 64).

Methods:

We obtained clinical data and metabolomic profiles for each individual, in which low molecular weight metabolites, lipids and lipoproteins (including particle concentrations and sizes) were measured by NMR spectroscopy. Immunological recovery was defined as reaching CD4⁺ T-cell count at least 250 cells/μl after 36 months of virologically successful ART. We used univariate comparisons, Random Forest test and receiver-operating characteristic curves to identify and evaluate the predictive factors of immunological recovery after treatment.

Results:

HIV-infected patients with a baseline metabolic pattern characterized by high levels of large high density lipoprotein (HDL) particles, HDL cholesterol and larger sizes of low density lipoprotein particles had a better immunological recovery after treatment. Conversely, patients with high ratios of non-HDL lipoprotein particles did not experience this full recovery. Medium very-low-density lipoprotein particles and glucose increased the classification power of the multivariate model despite not showing any significant differences between the two groups.

Conclusion:

In HIV-infected patients, a baseline healthier metabolomic profile is related to a better response to ART where the lipoprotein profile, mainly large HDL particles, may play a key role.

Lipid Abnormalities and Inflammation in HIV Inflection

Infection with the human immunodeficiency virus (HIV), and subsequent treatment with antiretroviral therapy (ART), is often associated with perturbations in lipid profiles. Furthermore, persistent inflammation, in spite of suppression of viral replication by ART, likely contributes to modifications in lipid composition and function, exacerbating risk for development of cardiovascular disease (CVD). Increased levels of several pro-inflammatory lipid species, including oxidized low-density lipoprotein (LDL) and high-density lipoprotein (HDL), have been measured in HIV-infected persons and are associated with markers of immune activation. The mechanisms linked to this bidirectional relationship in which inflammation increases lipid levels and promotes their modification, and these modified lipid species perpetuate inflammatory processes, require further investigation. Treatment with statins and other lifestyle modifications, including improvement in dietary intake and exercise, are critical to reducing CVD risk. Well-designed clinical trials that take into account the complex relationships among lipids and inflammation within persons infected with HIV need to be considered.

Paraoxonases and infectious diseases

The paraoxonases (PON1, PON2 and PON3) are an enzyme family with a high structural homology. All of them have lactonase activity and degrade lipid peroxides in lipoproteins and cells. As such, they play a role in protection against oxidation and inflammation. Infectious diseases are often associated with oxidative stress and an inflammatory response. Infection and inflammation trigger a cascade of reactions in the host, known as the acute-phase response. This response is associated with dramatic changes in serum proteins and lipoproteins, including a decrease in serum PON1 activity. These alterations have clinical consequences for the infected patient, including an increased risk for cardiovascular diseases, and an impaired protection against the formation of antibiotic-resistant bacterial biofilms. Several studies have investigated the value of serum PON1 measurement as a biomarker of the infection process. Low serum PON1 activities are associated with poor survival in patients with severe sepsis. In addition, preliminary studies suggest that serum PON1 concentration and/or enzyme activity may be useful as markers of acute concomitant infection in patients with an indwelling central venous catheter. Investigating the associations between paraoxonases and infectious diseases is a recent, and productive, line of research.

Lack of effects of statins on high-density lipoprotein subfractions in HIV-1-infected patients receiving protease inhibitors

BACKGROUND

We evaluated the effect of 45 days of rosuvastatin or pravastatin treatment on the distribution of HDL subfractions in HIV-1-infected individuals receiving boosted protease inhibitors (PIs) with cardiovascular risk.

METHODS

The distribution of HDL subclasses by gradient gel electrophoresis was blindly assessed in 74 HIV-1-infected individuals receiving boosted PIs at baseline and at day 45 of statin treatment, and compared with the distribution obtained in 63 healthy normolipidemic individuals taken as controls.

RESULTS

No significant modification appeared in HDL distribution between the two arms of statins for the HIV-1-infected individuals. Nevertheless, when compared to controls, HDL subfractions showed a significantly lower HDL2b proportion and significantly higher proportions of HDL2a and HDL3b (P<0.001).

CONCLUSION

No difference was observed in HDL distribution between pravastatin and rosuvastatin after 45 days treatment, in HIV-1-infected individuals under PIs. Nevertheless, when compared to healthy normolipidemic subjects, HDL distribution is clearly different, with a distribution in HIV-infected individuals under PIs associated with an increased cardiovascular risk.

Risk of Cardiovascular Disease in an Aging HIV Population: Where Are We Now?

With more effective and widespread antiretroviral treatment, the overall incidence of AIDS- or HIV-related death has decreased dramatically. Consequently, as patients are aging, cardiovascular disease (CVD) has emerged as an important cause of morbidity and mortality in the HIV population. The incidence of CVD overall in HIV is relatively low, but it is approximately 1.5-2-fold higher than that seen in age-matched HIV-uninfected individuals. Multiple factors are believed to explain this excess in risk such as overrepresentation of traditional cardiovascular risk factors (particularly smoking), toxicities associated with cumulative exposure to some antiretroviral agents, together with persistent chronic inflammation, and immune activation associated with HIV infection. Tools are available to calculate an individual's predicted risk of CVD and should be incorporated in the regular follow-up of HIV-infected patients. Targeted interventions to reduce this risk must be recommended, including life-style changes and medical interventions that might include changes in antiretroviral therapy.

Risk factors and assessment for cardiovascular disease among HIV-positive patients attending a Nigerian tertiary hospital

INTRODUCTION

Cardiovascular risk factors are prevalent in HIV-positive patients which places them at increased risk for cardiovascular disease (CVD). We aimed to determine the risk factors and risk assessment for CVD in HIV-positive patients with and without antiretroviral therapy.

METHODS

This was a cross-sectional study of HIV-positive patients attending the Lagos University Teaching Hospital, Nigeria. Anthropometric and blood pressure measurements were performed; fasting lipid profile, plasma glucose, homocysteine and hsCRP were determined, as well as prevalences and risk assessments. Statistical tests were used to compare the groups and p-value <0.05 was considered to be significant.

RESULTS

283 subjects were recruited for this study (100 HIV-positive treatment-naive, 100 HIV-positive treated and 83 HIV negative controls). Compared to the controls, mean (sd) values were significantly higher among HIV-treated subjects: waist circumference = 88.7 (10.4), p = 0.035; systolic bp= 124.9 (20.7), p = 0.014; glucose= 5.54 (1.7), p = 0.015; triglyceride= 2.0 (1.2), p < 0.001; homocysteine= 10.9 (8.9-16.2), p = 0.0003; while hsCRP= 2.9 (1.4-11.6), p = 0.002 and HDL-C = 0.9 (0.4), p = < 0.0001 were higher among the HIV-naïve subjects. Likewise, higher prevalences of the risk factors were noted among the HIV-treated subjects except low HDL-C (p < 0.001) and hsCRP (p = 0.03) which were higher in the HIV-naïve group. Risk assessment using ratios showed high risk for CVD especially in the HIV-naïve group. The median range for Framingham risk assessment was 1.0 - 7.5%.

CONCLUSION

Risk factors and risk assessment for CVD are increased in HIV-positive patients with and without antiretroviral therapy. Routine evaluation and risk assessment for CVD irrespective of therapy status is necessary to prevent future cardiovascular events.

Systemic and cell-specific mechanisms of vasculopathy induced by human immunodeficiency virus and highly active antiretroviral therapy

OBJECTIVE

Patients infected with human immunodeficiency virus (HIV) have higher rates of dyslipidemia, atherosclerosis, and chronic inflammation that can damage the vascular system compared with the general population. This can be attributed both to HIV itself and to highly active antiretroviral therapy (HAART) they receive. This review outlines the mechanisms by which HIV and HIV medications can cause vascular complications and identifies strategic areas of research to treat these dysfunctions.

REVIEW

HIV and HAART affect the vascular system through several mechanisms that target systemic or metabolic systems and specific cells. HIV causes dyslipidemia and chronic immune activation, which can contribute to atherosclerosis. In addition, HIV damages macrophages, endothelial cells, smooth muscle cells, and platelets, and this damage also plays a role in the development of atherosclerosis. HAART, particularly protease inhibitors, interferes with cholesterol metabolism and can affect macrophages, endothelial cells, and smooth muscle cells. The metabolic changes and cell damage induced by HIV and HAART put HIV patients at increased risk for atherosclerosis, dyslipidemia, and serious cardiovascular events such as myocardial infarction and stroke.

CONCLUSIONS

HIV patients have increased risk of developing potentially life-threatening cardiovascular pathology, which cannot be explained by traditional cardiovascular risk factors alone. More research is needed into therapies to target this HIV-specific vasculopathy.

Heart failure in patients with human immunodeficiency virus: a review of the literature

Coronary artery disease represents the leading cause of death for HIV patients treated with highly active antiretroviral treatment. Besides this, an extensive amount of data related to the risk of overt heart failure and consequently of atrial fibrillation and sudden cardiac death (SCD) in this population has been reported. It seems that persistent deregulation of immunity in HIV-infected patients is a common pathway related to both of these adverse clinical outcomes. Despite the fact that atrial fibrillation and heart failure are relatively common in HIV, few data are reported about screening, diagnosis, and potential treatment of these conditions.

Prevalence of Dyslipidemia Among Antiretroviral-Naive HIV-Infected Individuals in China

Little is known about the epidemiological features of dyslipidemia among antiretroviral-naive HIV-infected individuals in China. We used a cross-sectional study design to estimate the prevalence of dyslipidemia in this population, and to identify risk factors associated with the presence of dyslipidemia. One thousand five hundred and eighteen antiretroviral-naive HIV-infected individuals and 347 HIV-negative subjects in China were enrolled during 2009 to 2010. Demographics and medical histories were recorded. After an overnight fast, serum samples were collected to measure lipid levels. Factors associated with the presence of dyslipidemia were analyzed by logistic regression. Mean total cholesterol (TC), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL) levels were lower in HIV-positive than HIV-negative subjects, but mean triglyceride (TG) was higher in HIV-positive subjects. The overall prevalence of dyslipidemia in HIV-positive and HIV-negative groups did not differ (75.6% vs. 73.7%, P = 0.580). However, the prevalence of high TC (8.4% vs. 28.2%, P < 0.001) and high LDL (8.5% vs. 62.6%, P < 0.001) was lower in HIV-positive than HIV-negative subjects, and the prevalence of high TG (33.9% vs. 17.0%, P < 0.001) and low HDL (59.6% vs. 11.2%, P < 0.001) was higher in HIV-positive than HIV-negative subjects. Logistic analysis showed that HIV positivity was significantly associated with both an increased risk of high TG and low HDL and a decreased risk of high TC and high LDL. The mean levels of TC, of LDL and of HDL showed an increasing trend with increasing CD4 count in HIV-positive subjects. Multivariable logistic regression found that lower CD4 count was significantly associated with both an increased risk of high TG and low HDL and a decreased risk of high TC in HIV-positive subjects. Among antiretroviral-naive HIV-infected Chinese adults, there was a high prevalence of dyslipidemia characterized by high TG and low HDL, which was associated with lower CD4 counts. These data support the assessment of lipid profiles before and after initiation of antiretroviral therapy regardless of age.

Treatment of dyslipidemia in HIV

Patients infected with HIV have a high risk of developing dyslipidemia. Effective therapeutic strategies can be challenging due to an increase risk of drug interactions and other comorbidities. Understanding the underlying pathophysiology and the principles of pharmacological and non-pharmacological therapeutic interventions can be of value in the appropriate management of dyslipidemia in the HIV-infected patient.

Clinical and demographic factors associated with low viral load in early untreated HIV infection in the INSIGHT Strategic Timing of AntiRetroviral Treatment (START) trial

OBJECTIVES

A small subset of HIV-positive adults have low HIV RNA in the absence of therapy, sometimes for years. Clinical factors associated with low HIV RNA in early infection have not been well defined.

METHODS

We assessed factors associated with low plasma HIV RNA level at study entry in the Strategic Timing of AntiRetroviral Treatment (START) trial. All START participants had a baseline HIV RNA assessment within 60 days prior to randomization. The key covariables considered for this analysis were race, and hepatitis B virus (HBV) and hepatitis C virus (HCV) status. We assessed factors associated with HIV RNA ≤ 50 and ≤ 400 HIV-1 RNA copies/mL using logistic regression. Because of the strong association between region of randomization and baseline low HIV RNA, analyses were stratified by region.

RESULTS

We found that, of 4676 eligible participants randomized in START with a baseline HIV RNA assessment, 113 (2.4%) had HIV RNA ≤ 50 copies/mL at baseline, and a further 257 (5.5%) between 51 and 400 copies/mL. We found that HIV exposure routes other than male homosexual contact, higher high-density lipoprotein (HDL) cholesterol levels, higher CD4 cell counts, and higher CD4:CD8 ratio were associated with increased odds of low HIV RNA. HCV antibody positivity was borderline statistically significantly associated with low HIV RNA. Race and HBV surface antigen positivity were not significantly associated with low HIV RNA.

CONCLUSIONS

In a modern cohort of individuals with early untreated HIV infection, we found that HIV exposure routes other than male homosexual contact and higher HDL cholesterol were associated with increased odds of low HIV RNA.

HIV infection induces structural and functional changes in high density lipoproteins

BACKGROUND AND AIMS

Coronary artery disease is a growing clinical problem in HIV-infected subjects. The increased risk of coronary events in this population has been linked to low levels of HDL, but the effects of HIV infection and anti-retroviral treatment (ART) on HDL structure and function remain unknown. Here, we aimed to determine the composition and function of HDL particles isolated from ART-naive and ART-positive HIV-infected patients.

METHODS AND RESULTS

Proteomic profiling revealed decreased levels of paraoxonase (PON) 1 and PON 3 in HDL from HIV patients relative to HDL from uninfected controls (p < 0.0001), and PON activity of HDL from control group (0.13 ± 0.01 U/μl) was significantly higher than PON activity of HDL from HIV-infected untreated subjects (0.12 ± 0.01 U/μl, p = 0.0035), subjects treated with non-nucleoside reverse transcriptase inhibitor (NNRTI)-based therapy (0.11 ± 0.01 U/μl, p < 0.0001), subjects treated with protease inhibitor (PI)-based therapy with detectable viral load (0.11 ± 0.01 U/μl, p < 0.0001), and PI-treated patients with undetectable viral load (0.12 ± 0.01 U/μl, p = 0.0164). Lipidomic profiling uncovered a negative correlation between CD4 T cell counts and particle sphingomyelin, lyso-phosphatidylcholine and ether-linked phosphatidylserine content in the ART-naive (R(2) = 0.2611, p < 0.05; R(2) = 0.2722, p < 0.05; and R(2) = 0.3977, p < 0.05, respectively) but not treated HIV-infected subjects. Functional analysis demonstrated a negative correlation between cholesterol efflux capacity of HDL and viral load in the ART-naive HIV-infected group (R(2) = 0.26, p = 0.026).

CONCLUSIONS

Taken together, these results indicate that HIV infection associates with a number of both protein and lipid compositional changes in HDL particles. Moreover, HIV infection affects cholesterol efflux function of HDL, thus contributing to an increased risk of atherosclerosis in this patient population.

Lipid metabolism in patients infected with Nef-deficient HIV-1 strain

BACKGROUND

HIV protein Nef plays a key role in impairing cholesterol metabolism in both HIV infected and bystander cells. The existence of a small cohort of patients infected with Nef-deficient strain of HIV presented a unique opportunity to test the effect of Nef on lipid metabolism in a clinical setting.

METHODS

Here we report the results of a study comparing six patients infected with Nef-deficient strain of HIV (ΔNefHIV) with six treatment-naïve patients infected with wild-type HIV (WT HIV). Lipoprotein profile, size and functionality of high density lipoprotein (HDL) particles as well as lipidomic and microRNA profiles of patient plasma were analyzed.

RESULTS

We found that patients infected with ΔNefHIV had lower proportion of subjects with plasma HDL-C levels <1 mmol/l compared to patients infected with WT HIV. Furthermore, compared to a reference group of HIV-negative subjects, there was higher abundance of smaller under-lipidated HDL particles in plasma of patients infected with WT HIV, but not in those infected with ΔNefHIV. Lipidomic analysis of plasma revealed differences in abundance of phosphatidylserine and sphingolipids between patients infected with ΔNefHIV and WT HIV. MicroRNA profiling revealed that plasma abundance of 24 miRNAs, many of those involved in regulation of lipid metabolism, was differentially regulated by WT HIV and ΔNefHIV.

CONCLUSION

Our findings are consistent with HIV protein Nef playing a significant role in pathogenesis of lipid-related metabolic complications of HIV disease.

Oxidized LDL Levels Are Increased in HIV Infection and May Drive Monocyte Activation

BACKGROUND

HIV infection is associated with increased cardiovascular risk, and this risk correlates with markers of monocyte activation. We have shown that HIV is associated with a prothrombotic monocyte phenotype, which can be partially mitigated by statin therapy. We therefore explored the relationship between oxidized low-density lipoprotein (oxLDL) particles and monocyte activation.

METHODS

We performed phenotypic analysis of monocytes using flow cytometry on fresh whole blood in 54 patients with HIV and 24 controls without HIV. Plasma levels of oxLDL, soluble CD14, IL-6, and soluble CD163 were measured by enzyme-linked immunosorbent assay. In vitro experiments were performed using flow cytometry.

RESULTS

Plasma levels of oxLDL were significantly increased in HIV infection compared with controls (60.1 units vs. 32.1 units, P < 0.001). Monocyte expression of the oxLDL receptors, CD36 and Toll-like receptor 4, was also increased in HIV. OxLDL levels correlated with markers of monocyte activation, including soluble CD14, tissue factor expression on inflammatory monocytes, and CD36. In vitro stimulation with oxLDL, but not to low-density lipoprotein, resulted in expansion of inflammatory monocytes and increased monocyte expression of tissue factor, recapitulating the monocyte profile we find in HIV disease.

CONCLUSIONS

OxLDL may contribute to monocyte activation, and further study in the context of HIV disease is warranted.

Stimulation of Liver X Receptor Has Potent Anti-HIV Effects in a Humanized Mouse Model of HIV Infection

Previous studies demonstrated that liver X receptor (LXR) agonists inhibit human immunodeficiency virus (HIV) replication by upregulating cholesterol transporter ATP-binding cassette A1 (ABCA1), suppressing HIV production, and reducing infectivity of produced virions. In this study, we extended these observations by analyzing the effect of the LXR agonist T0901317 [N-[4-(1,1,1,3,3,3-hexafluoro-2-hydroxypropan-2-yl)phenyl]-N-(2,2,2-trifluoroethyl)benzenesulfonamide] on the ongoing HIV infection and investigating the possibility of using LXR agonist for pre-exposure prophylaxis of HIV infection in a humanized mouse model. Pre-exposure of monocyte-derived macrophages to T0901317 reduced susceptibility of these cells to HIV infection in vitro. This protective effect lasted for up to 4 days after treatment termination and correlated with upregulated expression of ABCA1, reduced abundance of lipid rafts, and reduced fusion of the cells with HIV. Pre-exposure of peripheral blood leukocytes to T0901317 provided only a short-term protection against HIV infection. Treatment of HIV-exposed humanized mice with LXR agonist starting 2 weeks postinfection substantially reduced viral load. When eight humanized mice were pretreated with LXR agonist prior to HIV infection, five animals were protected from infection, two had viral load at the limit of detection, and one had viral load significantly reduced relative to mock-treated controls. T0901317 pretreatment also reduced HIV-induced dyslipidemia in infected mice. In conclusion, these results reveal a novel link between LXR stimulation and cell resistance to HIV infection and suggest that LXR agonists may be good candidates for development as anti-HIV agents, in particular for pre-exposure prophylaxis of HIV infection.

Changes in Inflammation and Immune Activation With Atazanavir-, Raltegravir-, Darunavir-Based Initial Antiviral Therapy: ACTG 5260s

BACKGROUND

It is unclear whether the integrase inhibitor raltegravir (RAL) reduces inflammation and immune activation compared with ritonavir-boosted protease inhibitors (PIs).

METHODS

In a prospective, randomized, multicenter clinical trial that included 328 human immunodeficiency type 1 (HIV-1)-infected, treatment-naive participants were randomized to receive tenofovir disoproxil fumarate-emtricitabine (TDF/FTC) plus atazanavir/ritonavir (ATV/r), darunavir/ritonavir (DRV/r), or RAL. A total of 234 participants (71%) with HIV-1 RNA levels <50 copies/mL by week 24 were included. Plasma biomarkers of inflammation and coagulation that were analysed included high-sensitivity C-reactive protein, interleukin-6 (IL-6), GlycA, D-dimer, soluble CD14 (sCD14), sCD163, and sIL-2r; blood cellular markers included %CD38+DR+ of T-cell subsets and %CD14+CD16+ and%CD14(dim)CD16+ monocyte subsets. Changes from baseline were examined at earlier (24 or 48 weeks) and later (96 weeks) time points, with 95% confidence intervals on fold-change. Pairwise treatment groups were compared using Wilcoxon rank sum tests, with P values adjusted for false discovery rate control.

RESULTS

Changes in biomarkers varied by regimen during the 96 weeks of follow-up as follows: hsCRP declined with ATV/r and RAL, IL-6 declined only with RAL, and GLycA decreased in all groups. D-dimer declined with ATV/r and DRV/r and was unchanged with RAL. Markers of T-cell activation and sCD163 (but not sCD14 and CD14-+CD16+) declined in all groups.

CONCLUSIONS

Despite some differences in specific markers of inflammation and immune activation between the antiretroviral therapy (ART) regimens, we found no consistent evidence that the reduction of inflammation and immune activation with ART initiation was different between RAL and PI-based regimens.

CLINICAL TRIALS REGISTRATION

NCT00811954 and NCT00851799.

Epidemiology and management of antiretroviral-associated cardiovascular disease

Risk and manifestations of cardiovascular disease (CVD) in patients infected with human immunodeficiency virus (HIV) will continue to evolve as improved treatments and life expectancy of these patients increases. Although initiation of antiretroviral (ARV) therapy has been shown to reduce this risk, some ARV medications may induce metabolic abnormalities, further compounding the risk of CVD. In this patient population, both pharmacologic and nonpharmacologic strategies should be employed to treat and reduce further risk of CVD. This review summarizes epidemiology data of the risk factors and development of CVD in HIV and provides recommendations to manage CVD in HIV-infected patients.

Plasma cholesterol efflux capacity from human THP-1 macrophages is reduced in HIV-infected patients: impact of HAART

The capacity of HDL to remove cholesterol from macrophages is inversely associated with the severity of angiographic coronary artery disease. The effect of human immunodeficiency virus (HIV) infection or its treatment on the ability of HDL particles to stimulate cholesterol efflux from human macrophages has never been studied. We evaluated the capacity of whole plasma and isolated HDL particles from HIV-infected subjects (n = 231) and uninfected controls (n = 200), as well as in a subset of 41 HIV subjects receiving highly active antiretroviral therapy (HAART) to mediate cholesterol efflux from human macrophages. Plasma cholesterol efflux capacity was reduced (-12%; P = 0.001) in HIV patients as compared with controls. HIV infection reduced by 27% (P < 0.05) the capacity of HDL subfractions to promote cholesterol efflux from macrophages. We observed a reduced ABCA1-dependent efflux capacity of plasma (-27%; P < 0.0001) from HIV-infected subjects as a result of a reduction in the efflux capacity of HDL3 particles. HAART administration restored the capacity of plasma from HIV patients to stimulate cholesterol efflux from human macrophages (9.4%; P = 0.04). During HIV infection, the capacity of whole plasma to remove cholesterol from macrophages is reduced, thus potentially contributing to the increased coronary heart disease in the HIV population. HAART administration restored the removal of cholesterol from macrophages by increasing HDL functionality.

Influence of immune activation and inflammatory response on cardiovascular risk associated with the human immunodeficiency virus

Patients infected with the human immunodeficiency virus (HIV) have an increased cardiovascular risk. Although initially this increased risk was attributed to metabolic alterations associated with antiretroviral treatment, in recent years, the attention has been focused on the HIV disease itself. Inflammation, immune system activation, and endothelial dysfunction facilitated by HIV infection have been identified as key factors in the development and progression of atherosclerosis. In this review, we describe the epidemiology and pathogenesis of cardiovascular disease in patients with HIV infection and summarize the latest knowledge on the relationship between traditional and novel inflammatory, immune activation, and endothelial dysfunction biomarkers on the cardiovascular risk associated with HIV infection.

HDL in infectious diseases and sepsis

During infection significant alterations in lipid metabolism and lipoprotein composition occur. Triglyceride and VLDL cholesterol levels increase, while reduced HDL cholesterol (HDL-C) and LDL cholesterol (LDL-C) levels are observed. More importantly, endotoxemia modulates HDL composition and size: phospholipids are reduced as well as apolipoprotein (apo) A-I, while serum amyloid A (SAA) and secretory phospholipase A2 (sPLA2) dramatically increase, and, although the total HDL particle number does not change, a significant decrease in the number of small- and medium-size particles is observed. Low HDL-C levels inversely correlate with the severity of septic disease and associate with an exaggerated systemic inflammatory response. HDL, as well as other plasma lipoproteins, can bind and neutralize Gram-negative bacterial lipopolysaccharide (LPS) and Gram-positive bacterial lipoteichoic acid (LTA), thus favoring the clearance of these products. HDLs are emerging also as a relevant player during parasitic infections, and a specific component of HDL, namely, apoL-1, confers innate immunity against trypanosome by favoring lysosomal swelling which kills the parasite. During virus infections, proteins associated with the modulation of cholesterol bioavailability in the lipid rafts such as ABCA1 and SR-BI have been shown to favor virus entry into the cells. Pharmacological studies support the benefit of recombinant HDL or apoA-I mimetics during bacterial infection, while apoL-1-nanobody complexes were tested for trypanosome infection. Finally, SR-BI antagonism represents a novel and forefront approach interfering with hepatitis C virus entry which is currently tested in clinical studies. From the coming years, we have to expect new and compelling observations further linking HDL to innate immunity and infections.

High-density lipoprotein-mediated cholesterol efflux capacity is improved by treatment with antiretroviral therapy in acute human immunodeficiency virus infection

Background

 Individuals infected with human immunodeficiency virus (HIV) have decreased high-density lipoprotein (HDL)-cholesterol and increased cardiovascular disease (CVD). Reverse cholesterol transport from macrophages may be inhibited by HIV and contribute to increased CVD. Human studies have not investigated longitudinal effects of HIV and antiretroviral therapy (ART) on cholesterol efflux.

Methods

 Subjects with acute HIV infection were randomized to ART or not. Cholesterol efflux capacity was determined ex vivo after exposure of murine macrophages to apolipoprotein B-depleted patient sera obtained at baseline and after 12 weeks.

Results

 After 12 weeks, HIV RNA decreased most in subjects randomized to ART. Available data on cholesterol demonstrated that efflux capacity from Abca1^+/+ macrophages was increased most by sera obtained from ART-treated subjects (20.5% ± 5.0% to 24.3 % ± 6.9%, baseline to 12 weeks, P = .007; ART group [n = 6] vs 18.0 % ± 3.9% to 19.1 % ± 2.9%, baseline to 12 weeks, P = .30; untreated group [n = 6] [P = .04 ART vs untreated group]). Change in HIV RNA was negatively associated with change in Abca1^+/+ macrophage cholesterol efflux (r = − 0.62, P = .03), and this finding remained significant (P = .03) after controlling for changes in HDL-cholesterol, CD4⁺ cells, and markers of monocyte or macrophage activation.

Conclusions

 In subjects acutely infected with HIV, ATP-binding cassette transporter A1-mediated cholesterol efflux was stimulated to a greater degree over time by apolipoprotein B-depleted serum from subjects randomized to ART. The improvement in cholesterol efflux capacity is independently related to reduction in viral load.