HIV envelope gp120 activates human arterial smooth muscle cells

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.

gp120 Envelope Glycoproteins of HIV-1 Group M Subtype A and Subtype B Differentially Affect Gene Expression in Human Vascular Endothelial Cells

Cardiovascular complications are seen among human immunodeficiency virus (HIV)-positive individuals, who now survive longer due to successful antiretroviral therapies. Pulmonary arterial hypertension (PAH) is a fatal disease characterized by increased blood pressure in the lung circulation. The prevalence of PAH in the HIV-positive population is dramatically higher than that in the general population. While HIV-1 Group M Subtype B is the most prevalent subtype in western countries, the majority of HIV-1 infections in eastern Africa and former Soviet Union countries are caused by Subtype A. Research on vascular complications in the HIV-positive population in the context of subtype differences, however, has not been rigorous. Much of the research on HIV has focused on Subtype B, and information on the mechanisms of Subtype A is nonexistent. The lack of such knowledge results in health disparities in the development of therapeutic strategies to prevent/treat HIV complications. The present study examined the effects of HIV-1 gp120 of Subtypes A and B on human pulmonary artery endothelial cells by performing protein arrays. We found that the gene expression changes caused by gp120s of Subtypes A and B are different. Subtype A is a more potent downregulator of perostasin, matrix metalloproteinase-2, and ErbB than Subtype B, while Subtype B is more effective in downregulating monocyte chemotactic protein-2 (MCP-2), MCP-3, and thymus- and activation-regulated chemokine proteins. This is the first report of gp120 proteins affecting host cells in an HIV subtype-specific manner, opening up the possibility that complications occur differently in HIV patients throughout the world.

Venous thromboembolism in viral diseases: A comprehensive literature review

Venous thromboembolism (VTE) is known to be a common respiratory and/or cardiovascular complication in hospitalized patients with viral infections. Numerous studies have proven human immunodeficiency virus infection to be a prothrombotic condition. An elevated VTE risk has been observed in critically ill H1N1 influenza patients. VTE risk is remarkably higher in patients infected with the Hepatitis C virus in contrast to uninfected subjects. The elevation of D-dimer levels supported the association between Chikungunya and the Zika virus and the rise of clinical VTE risk. Varicella-zoster virus is a risk factor for both cellulitis and the consequent invasive bacterial disease which may take part in thrombotic initiation. Eventually, hospitalized patients infected with the coronavirus disease of 2019 (COVID-19), the cause of the ongoing worldwide pandemic, could mainly suffer from an anomalous risk of coagulation activation with enhanced venous thrombosis events and poor quality clinical course. Although the risk of VTE in nonhospitalized COVID-19 patients is not known yet, there are a large number of guidelines and studies on thromboprophylaxis administration for COVID-19 cases. This study aims to take a detailed look at the effect of viral diseases on VTE, the epidemiology of VTE in viral diseases, and the diagnosis and treatment of VTE.

Cardiovascular Disease and Thrombosis in HIV Infection

HIV infection has transitioned from an acute, fatal disease to a chronic one managed by antiretroviral therapy. Thus, the aging population of people living with HIV (PLWH) continues to expand. HIV infection results in a dysregulated immune system, wherein CD4+ T cells are depleted, particularly in the gastrointestinal tract, disrupting the gut epithelial barrier. Long-term HIV infection is associated with chronic inflammation through potentially direct mechanisms caused by viral replication or exposure to viral proteins and indirect mechanisms resulting from increased translocation of microbial products from the intestine or exposure to antiretroviral therapy. Chronic inflammation (as marked by IL [interleukin]-6 and CRP [C-reactive protein]) in PLWH promotes endothelial cell dysfunction and atherosclerosis. PLWH show significantly increased rates of cardiovascular disease, such as myocardial infarction (risk ratio, 1.79 [95% CI, 1.54-2.08]) and stroke (risk ratio, 2.56 [95% CI, 1.43-4.61]). In addition, PLWH have increased levels of the coagulation biomarker D-dimer and have a two to ten-fold increased risk of venous thromboembolism compared with the general population. Several small clinical trials analyzed the effect of different antithrombotic agents on platelet activation, coagulation, inflammation, and immune cell activation. Although some markers for coagulation were reduced, most agents failed to reduce inflammatory markers in PLWH. More studies are needed to understand the underlying mechanisms driving inflammation in PLWH to create better therapies for lowering chronic inflammation in PLWH. Such therapies can potentially reduce atherosclerosis, cardiovascular disease, and thrombosis rates in PLWH and thus overall mortality in this population.

gp120 envelope glycoproteins of HIV-1 Group M Subtype A and Subtype B differentially affect gene expression in human vascular endothelial cells

Cardiovascular complications are seen among human immunodeficiency virus (HIV)-positive individuals who can now survive longer due to successful antiretroviral therapies. Among them, pulmonary arterial hypertension (PAH) is a fatal disease characterized by increased blood pressure in the lung circulation due to vasoconstriction and vascular wall remodeling, resulting in the overworking of the heart. The prevalence of PAH in the HIVpositive population is dramatically higher than that in the general population. While HIV-1 Group M Subtype B is the most prevalent subtype in western countries, the majority of HIV-1 infections in eastern Africa and former Soviet Union countries are caused by Subtype A. Research on the mechanism of vascular complications in the HIV-positive population, especially in the context of subtype differences, however, has not been rigorous. Much of the research on HIV has focused on Subtype B and information on the molecular mechanisms of Subtype A is non-existent. The lack of such knowledge results in health disparities in the development of therapeutic strategies to prevent/treat HIV complications. The present study examined the effects of HIV-1 viral fusion protein gp120 of Subtypes A and B on cultured human pulmonary artery endothelial cells by performing protein arrays. We found that the gene expression changes caused by the gp120s of Subtypes A and B are different. Specifically, Subtype A is a more potent downregulator of perostasin, matrix metalloproteinase-2 (MMP-2), and ErbB/Her3 than Subtype B, while Subtype B is more effective in downregulating monocyte chemotactic protein-2 (MCP-2/CCL8), MCP-3 (CCL7), and thymus- and activation-regulated chemokine (TARC/CCL17) proteins. This is the first report of gp120 proteins affecting host cells in an HIV subtype-specific manner, opening up the possibility that vascular complications may occur differently in HIV patients throughout the world.

Elevated Risk of Venous Thromboembolism in People Living with HIV

Human immunodeficiency virus (HIV) has been generally considered as a highly adaptive and rapidly evolving virus. It still constitutes a major public health problem all over the world despite an effective outcome in the prevention and reversal of the development and prognosis by using antiretroviral therapy. The salient question lies in the more frequent emergence of a series of comorbidities along with the prolongation of the life, which deeply affects the survival in such group. Venous thromboembolism (VTE) has been recognized to be the third most common cardiovascular condition within people living with HIV (PWH). In terms of its mechanism of action, the occurrence of VTE is quite multifactorial and complex in HIV. Prior exploration concerning the etiology of VTE in PWH identifies general, disease-specific, and miscellaneous factors for explaining its occurrence and development. VTE has constituted an important role in PWH and may increase its all-cause mortality. Therefore, it is quite necessary to understand VTE from the following aspects of epidemiology, pathophysiology, molecular mechanisms, and therapeutic interventions so as to balance the risks and benefits of anticoagulation and optimize corresponding treatment.

Viral Infection and Cardiovascular Disease: Implications for the Molecular Basis of COVID-19 Pathogenesis

The current pandemic of coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While this respiratory virus only causes mild symptoms in younger healthy individuals, elderly people and those with cardiovascular diseases such as systemic hypertension are susceptible to developing severe conditions that can be fatal. SARS-CoV-2 infection is also associated with an increased incidence of cardiovascular diseases such as myocardial injury, acute coronary syndrome, and thromboembolism. Understanding the mechanisms of the effects of this virus on the cardiovascular system should thus help develop therapeutic strategies to reduce the mortality and morbidity associated with SARS-CoV-2 infection. Since this virus causes severe and fatal conditions in older individuals with cardiovascular comorbidities, effective therapies targeting specific populations will likely contribute to ending this pandemic. In this review article, the effects of various viruses—including other coronaviruses, influenza, dengue, and human immunodeficiency virus—on the cardiovascular system are described to help provide molecular mechanisms of pathologies associated with SARS-CoV-2 infection and COVID-19. The goal is to provide mechanistic information from the biology of other viral infections in relation to cardiovascular pathologies for the purpose of developing improved vaccines and therapeutic agents effective in preventing and/or treating the acute and long-term consequences of SARS-CoV-2 and COVID-19.

SARS-CoV-2 Spike Protein and Lung Vascular Cells

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing the current pandemic of coronavirus disease 2019 (COVID-19), and COVID-19 vaccines focus on its spike protein. However, in addition to facilitating the membrane fusion and viral entry, the SARS-CoV-2 spike protein promotes cell growth signaling in human lung vascular cells, and patients who have died of COVID-19 have thickened pulmonary vascular walls, linking the spike protein to a fatal disease, pulmonary arterial hypertension (PAH). In addition to SARS-CoV spike proteins, gp120, the viral membrane fusion protein of human immunodeficiency virus (HIV), has been reported to promote cell signaling, and long-term surviving HIV-positive patients have a high incidence of developing PAH. This article describes the findings of the SARS-CoV-2 spike protein affecting lung vascular cells and explains how the spike protein possibly increases the incidence of PAH. Since the SARS-CoV-2 spike protein will be administered to millions of people as COVID-19 vaccines, it is critical to understand the biological effects of this protein on human cells to ensure that it does not promote long-term adverse health consequences.

Correlating Fibrinogen Consumption and Profiles of Inflammatory Molecules in Human Envenomation's by Bothrops atrox in the Brazilian Amazon

Snakebites are considered a major public health problem worldwide. In the Amazon region of Brazil, the snake Bothrops atrox (B. atrox) is responsible for 90% of the bites. These bites may cause local and systemic signs from acute inflammatory reaction and hemostatic changes, and present common hemorrhagic disorders. These alterations occur due the action of hemostatically active and immunogenic toxins which are capable of triggering a wide range of hemostatic and inflammatory events. However, the crosstalk between coagulation disorders and inflammatory reaction still has gaps in snakebites. Thus, the goal of this study was to describe the relationship between the consumption of fibrinogen and the profile of inflammatory molecules (chemokines and cytokines) in evenomations by B. atrox snakebites. A prospective study was carried out with individuals who had suffered B. atrox snakebites and presented different levels of fibrinogen consumption (normal fibrinogen [NF] and hypofibrinogenemia [HF]). Seventeen patients with NF and 55 patients with HF were eligible for the study, in addition to 50 healthy controls (CG). The molecules CXCL-8, CCL-5, CXCL-9, CCL-2, CXCL-10, IL-6, TNF, IL-2, IL-10, IFN-γ, IL-4, and IL-17A were quantified in plasma using the CBA technique at three different times (pre-antivenom therapy [T0], 24 h [T1], and 48 h [T2] after antivenom therapy). The profile of the circulating inflammatory response is different between the groups studied, with HF patients having higher concentrations of CCL-5 and lower IFN-γ. In addition, antivenom therapy seems to have a positive effect, leading to a profile of circulating inflammatory response similar in quantification of T1 and T2 on both groups. Furthermore, these results suggest that a number of interactions of CXCL-8, CXCL-9, CCL-2, IL-6, and IFN-γ in HF patients are directly affected by fibrinogen levels, which may be related to the inflammatory response and coagulation mutual relationship induced by B. atrox venom. The present study is the first report on inflammation-coagulation crosstalk involving snakebite patients and supports the better understanding of envenomation's pathophysiology mechanisms and guides in the search for novel biomarkers and prospective therapies.

Potential cell-specific functions of CXCR4 in atherosclerosis

Der Chemokinrezeptor CXCR4 and sein Ligand CXCL12 bilden eine wichtige Achse in der Regulation von Zellfunktionen bei normaler Homöostase und bei Erkrankungen. Zusätzlich kann der atypische CXCL12 Rezeptor CXCR7 die Verfügbarkeit und Funktion von CXCL12 modulieren. Neben ihrer Rolle in der Mobilisierung von Stamm- und Vorläuferzellen, können CXCR4 und CXCL12 auch die Entwicklung der Atherosklerose über verschiedene Zellfunktionen beeinflussen. Dieser kurze Übersichtsartikel fasst das gegenwärtige Wissen zu den zellspezifischen Funktionen von CXCL12 und den Rezeptoren CXCR4 und CXCR7 mit möglichen Implikationen für die Entstehung und Progression der Atherosklerose zusammen

Effect of Cocaine on Pulmonary Vascular Remodeling and Hemodynamics in Human Immunodeficiency Virus-Transgenic Rats

Human immunodeficiency virus (HIV)-related pulmonary arterial hypertension has been found to be more prevalent in intravenous drug users. Our earlier cell-culture findings reported down-regulation of bone morphogenetic protein receptors (BMPRs) in combination with enhanced proliferation of human pulmonary arterial smooth muscle cells (PASMCs) in the presence of HIV-Trans-activator of transcription (Tat) and cocaine compared with either treatment alone. Here, we report physiologic evidence of significant increases in mean pulmonary arterial pressure in HIV-transgenic (Tg) rats intraperitoneally administered 40 mg/kg body weight cocaine (HIV-cocaine group) once daily for 21 days when compared with HIV-Tg rats given saline (HIV group) or wild-type (WT) Fischer 334 rats treated with (WT-cocaine group) and without cocaine (WT group). In addition, right ventricle systolic pressure was also found to be significantly higher in the HIV-cocaine rats compared with the WT group. Significant down-regulation in protein expression of BMPR-2 and BMPR-1B was observed in total lung extract from HIV-cocaine rats compared with the other three groups. Furthermore, the PASMCs isolated from HIV-cocaine rats demonstrated a higher level of proliferation and lower levels of apoptosis compared with cells isolated from other rat groups. Interestingly, corroborating our earlier cell-culture findings, we observed higher expression of BMPR-2 and BMPR-1B messenger RNA and significantly lower levels of BMPR-2 and BMPR-1B protein in HIV-cocaine PASMCs compared with cells isolated from all other groups. In conclusion, our findings support an additive effect of cocaine and HIV on smooth muscle dysfunction, resulting in enhanced pulmonary vascular remodeling with associated elevation of mean pulmonary arterial pressure and right ventricle systolic pressure in HIV-Tg rats exposed to cocaine.

Local CXCR4 Upregulation in the Injured Arterial Wall Contributes to Intimal Hyperplasia

CXCR4 is a stem/progenitor cell surface receptor specific for the cytokine stromal cell‐derived factor‐1 (SDF‐1α). There is evidence that bone marrow‐derived CXCR4‐expressing cells contribute to intimal hyperplasia (IH) by homing to the arterial subintima which is enriched with SDF‐1α. We have previously found that transforming growth factor‐β (TGFβ) and its signaling protein Smad3 are both upregulated following arterial injury and that TGFβ/Smad3 enhances the expression of CXCR4 in vascular smooth muscle cells (SMCs). It remains unknown, however, whether locally induced CXCR4 expression in SM22 expressing vascular SMCs plays a role in neointima formation. Here, we investigated whether elevated TGFβ/Smad3 signaling leads to the induction of CXCR4 expression locally in the injured arterial wall, thereby contributing to IH. We found prominent CXCR4 upregulation (mRNA, 60‐fold; protein, 4‐fold) in TGFβ‐treated, Smad3‐expressing SMCs. Chromatin immunoprecipitation assays revealed a specific association of the transcription factor Smad3 with the CXCR4 promoter. TGFβ/Smad3 treatment also markedly enhanced SDF‐1α‐induced ERK1/2 phosphorylation as well as SMC migration in a CXCR4‐dependent manner. Adenoviral expression of Smad3 in balloon‐injured rat carotid arteries increased local CXCR4 levels and enhanced IH, whereas SMC‐specific depletion of CXCR4 in the wire‐injured mouse femoral arterial wall produced a 60% reduction in IH. Our results provide the first evidence that upregulation of TGFβ/Smad3 in injured arteries induces local SMC CXCR4 expression and cell migration, and consequently IH. The Smad3/CXCR4 pathway may provide a potential target for therapeutic interventions to prevent restenosis. Stem Cells2016;34:2744–2757

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.

Vasculoplacental complications in pregnant women with HIV infection: a case-control study

OBJECTIVE

Data from the international literature suggest that there may be an association between maternal human immunodeficiency virus (HIV) infection and vasculoplacental complications during pregnancy. Studies on this subject have reached discordant conclusions. The aim of this study was to assess the incidence of vasculoplacental complications during pregnancy in women with and without HIV infection.

STUDY DESIGN

This single-center case-control study compared the incidence of pregnancy-related hypertension, preeclampsia, eclampsia, and vascular intrauterine growth restriction in 280 women with HIV and 560 women not infected with HIV, matched for age, parity, and geographic origin.

RESULTS

The incidence rates of pregnancy-related hypertension, preeclampsia, eclampsia, and vascular growth restriction did not differ between the women with and without HIV infection. The overall incidence of vasculoplacental complications did not differ between the 2 groups (7.5% vs 9.8%, respectively; P = .27). The risk of these was not associated with exposure to antiretroviral treatments, viral load, or CD4 T-cell counts at the beginning of pregnancy.

CONCLUSION

This study shows no difference in the incidence of vasculoplacental complications between women with and without HIV infection.

Is the atherosclerotic process accentuated under conditions of HIV infection, antiretroviral therapy, and protease inhibitor exposure? Meta-analysis of the markers of arterial structure and function

OBJECTIVE

To evaluate the apparent association of human immunodeficiency virus (HIV) infection, antiretroviral therapy (ART), and protease inhibitor (PI) exposure with the functional and structural markers of vasculature.

METHODS

A meta-analysis of the relationship between HIV infection, ART, and PI exposure and the functional and structural markers of vasculature. A systematic literature search was performed electronically using specific eligibility criteria. Weighted mean difference (WMD) and corresponding 95% confidence interval (CI) were calculated and combined appropriately.

RESULTS

Fifty-seven articles were included with nine different outcomes. Compared with HIV-negative patients, HIV-positive patients demonstrated significant elevated intima-media thickness (IMT) (WMD (95% CI) = 0.042 (0.028-0.057)), increased pulse wave velocity (PWV) (0.538 (0.283-0.792)), and reduced flow-mediated vasodilation (FMD) (-2.049 (-2.806 to -1.293)). Elevated IMT was observed in HIV patients receiving ART when compared with those naïve to ART in the 20- to 40-year-old age group (0.078 (0.033-0.123)), the >40-year-old age group (0.038 (0.018-0.057)), and the group comprising >50% males (0.070 (0.041-0.099)). In addition, ART resulted in an increased PWV in HIV patients receiving ART in the group with >50% male proportion (0.628 (0.405-0.851)). HIV patients exposed to PI showed a significant trend toward elevated IMT (0.033 (0.007-0.058)) and increased PWV (0.264 (0.118-0.410)) compared with those without PI exposure.

CONCLUSIONS

The atherosclerotic process was accentuated by elevated IMT, increased PWV, and reduced FMD under condition of HIV infection. Comparison of ART-receiving with ART-naïve patients showed a significant trend toward elevated IMT and increased PWV, especially under treatment with PI-containing drugs.

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.

HIV-associated large-vessel vasculopathy: a review of the current and emerging clinicopathological spectrum in vascular surgical practice

An established relationship exists between human immunodeficiency virus (HIV) and the vascular system, which is characterised by clinical expressions of aneurysmal and occlusive disease that emanate from a common pathological process. The exact pathogenesis is currently unknown; attempts to implicate opportunistic pathogens have been futile. Theories converge on leucocytoclastic vasculitis with the vaso vasora as the vasculopathic epicentre. It is thought that the virus itself or viral proteins trigger the release of inflammatory mediators that cause endothelial dysfunction and smooth muscle proliferation leading to vascular injury and thrombosis. The beneficial effects of highly active anti-retroviral therapy alter the natural history of the disease profile and promote longevity but are negated by cardiovascular complications. Atherosclerosis is an emerging challenge. Presently patients are managed by standard surgical protocols because of non-existent universal surgical interventional guidelines. Clinical response to treatment is variable and often compounded by complications of graft occlusion, sepsis and poor wound healing. The clinical, imaging and pathological observations position HIV-associated large-vessel vasculopathy as a unique entity. This review highlights the spectrum of HIV-associated large-vessel aneurysmal, occlusive and atherosclerotic disease in vascular surgical practice.

Pulmonary Arterial Hypertension among HIV-Infected Children: Results of a National Survey and Review of the Literature

Since the advent of highly active anti-retroviral therapy, HIV-related mortality has decreased dramatically. As a consequence, patients are living longer, and HIV infection is becoming a chronic disease. Patients and caretakers have to deal with chronic complications of infection and treatment, such as cardiovascular diseases, which now represent an important health issue, even in the pediatric population. Prevalence of pulmonary arterial hypertension (PAH) in the adult HIV population is around 0.4-0.6%, which is around 1000- to 2500-fold more prevalent than in the general population. In recent adult PAH registries, HIV has been identified as the fourth cause of PAH, accounting for approximately 6-7% of cases. Therefore, regular screening is recommended in HIV-infected adults by many experts. If HIV-associated PAH is mainly reported in HIV-infected adults, pediatric cases have also been, albeit rarely, described. This scarcity may be due to a very low PAH prevalence, or due to the lack of systematic cardiovascular screening in pediatric patients. As PAH may manifest only years or decades after infection, a systematic screening should perhaps also be recommended to HIV-infected children. In this context, we retrospectively looked for PAH screening in children included in our national Swiss Mother and Child HIV cohort study. A questionnaire was sent to all pediatric infectious disease specialists taking care of HIV-infected children in the cohort. The questions tried to identify symptoms suggestive of cardiovascular risk factors and asked which screening test was performed. In the 71 HIV-infected children for which we obtained an answer, no child was known for PAH. However, only two had been screened for PAH, and the diagnosis was not confirmed. In conclusion, PAH in HIV-infected children is possibly underestimated due to lack of screening. Systematic echocardiographic evaluation should be performed in HIV-infected children.

The CXCL12/CXCR4 chemokine ligand/receptor axis in cardiovascular disease

The chemokine receptor CXCR4 and its ligand CXCL12 play an important homeostatic function by mediating the homing of progenitor cells in the bone marrow and regulating their mobilization into peripheral tissues upon injury or stress. Although the CXCL12/CXCR4 interaction has long been regarded as a monogamous relation, the identification of the pro-inflammatory chemokine macrophage migration inhibitory factor (MIF) as an important second ligand for CXCR4, and of CXCR7 as an alternative receptor for CXCL12, has undermined this interpretation and has considerably complicated the understanding of CXCL12/CXCR4 signaling and associated biological functions. This review aims to provide insight into the current concept of the CXCL12/CXCR4 axis in myocardial infarction (MI) and its underlying pathologies such as atherosclerosis and injury-induced vascular restenosis. It will discuss main findings from in vitro studies, animal experiments and large-scale genome-wide association studies. The importance of the CXCL12/CXCR4 axis in progenitor cell homing and mobilization will be addressed, as will be the function of CXCR4 in different cell types involved in atherosclerosis. Finally, a potential translation of current knowledge on CXCR4 into future therapeutical application will be discussed.

The CCR5 chemokine receptor mediates vasoconstriction and stimulates intimal hyperplasia in human vessels in vitro

AIMS

The chemokine receptor CCR5 and its inflammatory ligands have been linked to atherosclerosis, an accelerated form of which occurs in saphenous vein graft disease. We investigated the function of vascular smooth muscle CCR5 in human coronary artery and saphenous vein, vascular tissues susceptible to atherosclerosis, and vasospasm.

METHODS AND RESULTS

CCR5 ligands were vasoconstrictors in saphenous vein and coronary artery. In vein, constrictor responses to CCL4 were completely blocked by CCR5 antagonists, including maraviroc. CCR5 antagonists prevented the development of a neointima after 14 days in cultured saphenous vein. CCR5 and its ligands were expressed in normal and diseased coronary artery and saphenous vein and localized to medial and intimal smooth muscle, endothelial, and inflammatory cells. [(125)I]-CCL4 bound to venous smooth muscle with KD = 1.15 ± 0.26 nmol/L and density of 22 ± 9 fmol mg(-1) protein.

CONCLUSIONS

Our data support a potential role for CCR5 in vasoconstriction and neointimal formation in vitro and imply that CCR5 chemokines may contribute to vascular remodelling and augmented vascular tone in human coronary artery and vein graft disease. The repurposing of maraviroc for the treatment of cardiovascular disease warrants further investigation.

Arrest Functions of the MIF Ligand/Receptor Axes in Atherogenesis

Macrophage migration inhibitory factor (MIF) has been defined as an important chemokine-like function (CLF) chemokine with an essential role in monocyte recruitment and arrest. Adhesion of monocytes to the vessel wall and their transendothelial migration are critical in atherogenesis and many other inflammatory diseases. Chemokines carefully control all steps of the monocyte recruitment process. Those chemokines specialized in controlling arrest are typically immobilized on the endothelial surface, mediating the arrest of rolling monocytes by chemokine receptor-triggered pathways. The chemokine receptor CXCR2 functions as an important arrest receptor on monocytes. An arrest function has been revealed for the bona fide CXCR2 ligands CXCL1 and CXCL8, but genetic studies also suggested that additional arrest chemokines are likely to be involved in atherogenic leukocyte recruitment. While CXCR2 is known to interact with numerous CXC chemokine ligands, the CLF chemokine MIF, which structurally does not belong to the CXC chemokine sub-family, was surprisingly identified as a non-cognate ligand of CXCR2, responsible for critical arrest functions during the atherogenic process. MIF was originally identified as macrophage migration inhibitory factor (this function being eponymous), but is now known as a potent inflammatory cytokine with CLFs including chemotaxis and leukocyte arrest. This review will cover the mechanisms underlying these functions, including MIF’s effects on LFA1 integrin activity and signal transduction, and will discuss the structural similarities between MIF and the bona fide CXCR2 ligand CXCL8 while emphasizing the structural differences. As MIF also interacts with CXCR4, a chemokine receptor implicated in CXCL12-elicited lymphocyte arrest, the arrest potential of the MIF/CXCR4 axis will also be scrutinized as well as the recently identified role of pericyte MIF in attracting leukocytes exiting through venules as part of the pericyte “motility instruction program.”

Assessment of biomarkers of cardiovascular risk among HIV type 1-infected adolescents: role of soluble vascular cell adhesion molecule as an early indicator of endothelial inflammation

Cardiovascular disease (CVD) biomarkers were examined in a cohort of HIV-infected and HIV-uninfected adolescents who participated in Adolescent Trials Network study 083 utilizing samples from the Reaching for Excellence in Adolescent Care cohort, a longitudinal study of youth infected through adult risk behavior. Nonfasting blood samples from 97 HIV-infected and 81 HIV-uninfected adolescents infected by adult risk behaviors were analyzed for total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), very low-density lipoprotein (VLDL), triglycerides, apolipoprotein A-I, high-sensitivity C-reactive protein (hsCRP), soluble vascular adhesion molecule-1 (sVCAM-1), myeloperoxidase, and neopterin at baseline and 18 months later. Results were analyzed using ANOVA, Wilcoxon signed-rank, and paired t tests. Among infected subjects 67 received antiretroviral therapy and 30 were treatment naive. The HIV-infected and HIV-uninfected subjects were similar in gender, ethnicity, and cardiovascular risk factors such as smoking and obesity. In all groups lipid parameters were within accepted guidelines for cardiovascular risk. Among HIV-infected youth on antiretroviral therapy (ART), HDL and apoprotein A-I were significantly lower when compared to uninfected youth. hsCRP was not elevated and thus not predictive for risk in any group. sVCAM-1 levels were significantly elevated in both HIV-infected groups: 1,435 ng/ml and 1,492 ng/ml in untreated and treated subjects, respectively, and 1,064 ng/ml in the uninfected group (p<0.0001). Across all groups neopterin correlated with sVCAM at 18 months (Spearman correlation coefficient 0.58, p<0.0001). Only 9% of ART-treated subjects fully suppressed virus. Lipid profiles and hsCRP, traditional markers of cardiovascular disease, are not abnormal among HIV-infected youth but elevated sVCAM may be an early marker of atherosclerosis.

Progressive intracranial fusiform aneurysms and T-cell immunodeficiency

In the pediatric population, intracranial fusiform aneurysms have been associated with human immunodeficiency virus/acquired immunodeficiency syndrome and rarely with opportunistic infections related to other immunodeficiencies. The HIV virus and other infectious organisms have been implicated in the pathophysiology of these aneurysms. We present a child with T-cell immunodeficiency but no evidence of human immunodeficiency virus or opportunistic intracranial infections that developed progressive bilateral fusiform intracranial aneurysms. Our findings suggest a role of immunodeficiency or inflammation in the formation of some intracranial aneurysms.

HIV infection and stroke: current perspectives and future directions

HIV infection can result in stroke via several mechanisms, including opportunistic infection, vasculopathy, cardioembolism, and coagulopathy. However, the occurrence of stroke and HIV infection might often be coincidental. HIV-associated vasculopathy describes various cerebrovascular changes, including stenosis and aneurysm formation, vasculitis, and accelerated atherosclerosis, and might be caused directly or indirectly by HIV infection, although the mechanisms are controversial. HIV and associated infections contribute to chronic inflammation. Combination antiretroviral therapies (cART) are clearly beneficial, but can be atherogenic and could increase stroke risk. cART can prolong life, increasing the size of the ageing population at risk of stroke. Stroke management and prevention should include identification and treatment of the specific cause of stroke and stroke risk factors, and judicious adjustment of the cART regimen. Epidemiological, clinical, biological, and autopsy studies of risk, the pathogenesis of HIV-associated vasculopathy (particularly of arterial endothelial damage), the long-term effects of cART, and ideal stroke treatment in patients with HIV are needed, as are antiretrovirals that are without vascular risk.

The Relationship Between HIV Infection and Cardiovascular Disease

Over 30 million people are currently living with human immunodeficiency virus (HIV) infection, and over 2 million new infections occur per year. HIV has been found to directly affect vascular biology resulting in an increased risk of cardiovascular disease compared to uninfected persons. Although HIV infection can now be treated effectively with combination antiretroviral medications, significant toxicities such as hyperlipidemia, diabetes, and excess cardiovascular co-morbidity; as well as the potential for significant drug-drug interactions between HIV and cardiovascular medications, present new challenges for the management of persons infected with HIV. We first review basic principles of HIV pathogenesis and treatment and then discuss relevant clinical management strategies that will be useful for cardiologists who might be involved in the care of HIV infected patients.

HIV-Associated Venous Thromboembolism

HIV infection has been recognized as a prothrombotic condition and this association has now been proven by a large number of studies with a reported VTE frequency among HIV-infected patients ranging from 0.19% to 7,63 %/year. HIV infection is associated with a two to tenfold increased risk of venous thrombosis in comparison with a general population of the same age. Some risk factors demonstrated a strongest association with VTE such as, low CD4⁺ cell count especially in the presence of clinical AIDS, protein S deficiency, and protein C deficiency. Whereas other risk factors are still controversial like protease inhibitor therapy, presence of active opportunistic infections and presence of antiphospholipid antibodies, including anticardiolipin antibodies and lupus anticoagulant. Physicians caring for HIV positive patients should be able to recognize and treat not only the well-known opportunistic infections and malignancies associated with this chronic disease, but also be alert to the less well-known complications such as thromboses. Pulmonary embolism should be included in the differential diagnosis when patients with HIV/AIDS have unexplained dyspnea or hypoxemia. In younger individuals with VTE, especially men, without other identifiable risk factors for VTE, HIV should be considered. Because interactions between warfarin and antiretrovirals is possible, health care providers should also be alert to the potential of dangerously high or low INRs when they are giving anticoagulants to patients with HIV infection who are undergoing antiretroviral therapy.

Biomarkers and HIV-associated cardiovascular disease

PURPOSE OF REVIEW

Our goal is to summarize recent literature on biomarkers of cardiovascular disease (CVD) in the setting of HIV infection with an emphasis on those associated with clinical events.

RECENT FINDINGS

Epidemiological data have demonstrated that HIV infection is associated with increases in well established markers of inflammation and thrombosis, and levels of high sensitivity C-reactive protein, interleukin-6, and D-dimer predict CVD and mortality risk in HIV cohorts. Levels of interleukin-6, D-dimer and endothelial adhesion molecules increase when antiretroviral therapy is interrupted, suggesting that HIV replication may be driving CVD risk in this context. However, data on changes in many CVD biomarkers after starting antiretroviral therapy are inconsistent or lacking. Finally, high-density lipoprotein particles may be more informative than other lipoprotein measures for CVD risk specifically among individuals with HIV infection.

SUMMARY

Biomarkers of inflammation and thrombosis have the potential to improve CVD risk stratification beyond traditional and HIV-specific factors, and may prove useful for evaluating CVD prevention strategies for individuals with HIV infection.

The identification of unique serum proteins of HIV-1 latently infected long-term non-progressor patients

BACKGROUND

The search for disease biomarkers within human peripheral fluids has become a favorable approach to preventative therapeutics throughout the past few years. The comparison of normal versus disease states can identify an overexpression or a suppression of critical proteins where illness has directly altered a patient's cellular homeostasis. In particular, the analysis of HIV-1 infected serum is an attractive medium with which to identify altered protein expression due to the ease and non-invasive methods of collecting samples as well as the corresponding insight into the in vivo interaction of the virus with infected cells/tissue. The utilization of proteomic techniques to globally identify differentially expressed serum proteins in response to HIV-1 infection is a significant undertaking that is complicated due to the innate protein profile of human serum.

RESULTS

Here, the depletion of 12 of the most abundant serum proteins, followed by two-dimensional gel electrophoresis coupled with identification of these proteins using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, has allowed for the identification of differentially expressed, low abundant serum proteins. We have analyzed and compared serum samples from HIV-1 infected subjects who are being treated using highly active antiretroviral therapy (HAART) to those who are latently infected but have not progressed to AIDS despite the absence of treatment, i.e. long term non-progressors (LTNPs). Here we have identified unique serum proteins that are differentially expressed in LTNP HIV-1 patients and may contribute to the ability of these patients to combat HIV-1 infection in the absence of HAART. We focused on the cdk4/6 cell cycle inhibitor p16INK4A and found that the treatment of HIV-1 latently infected cell lines with p16INK4A decreases viral production despite it not being expressed endogenously in these cells.

CONCLUSIONS

Identification of these unique proteins may serve as an indication of altered viral states in response to infection as well as a natural phenotypic variability in response to HIV-1 infection in a given population.

Traditional risk factors and D-dimer predict incident cardiovascular disease events in chronic HIV infection

OBJECTIVE

Cardiovascular disease (CVD) contributes significantly to HIV-related morbidity and mortality. Chronic immune activation and inflammation are thought to augment the progression of atherosclerotic disease. In this retrospective, case-control study of HIV-infected individuals, we investigated the association of traditional cardiac risk factors, HIV-related disease, and inflammation with CVD events.

METHODS

HIV-infected individuals who experienced an incident CVD event while enrolled in National Institutes of Health clinical protocols from 1995 to 2009 were matched 2: 1 to HIV-infected individuals without known CVD. Markers of inflammation and cell activation were measured in serum or plasma using ELISA-based assays and peripheral mononuclear cells by four-color flow cytometry.

RESULTS

Fifty-two patients experienced an incident CVD event. Events were related to smoking, dyslipidemia, hyperglycemia, and family history as well as elevated D-dimer, soluble vascular cell adhesion molecule-1, tissue inhibitor of metalloproteinase-1, and soluble tissue factor, but not high-sensitivity C-reactive protein. No significant differences in antiviral therapy, CD4 T-cell count, or CD38 and human leukocyte antigen-DR expression were identified between patients and controls. In multivariable analysis, smoking, family history, D-dimer, and glucose were independently related to CVD risk.

CONCLUSION

In this cohort, CVD risk was related to traditional CVD risk factors and markers of thrombosis and endothelial damage, but not to high-sensitivity C-reactive protein or markers of T-cell activation such as CD38/human leukocyte antigen-DR coexpression. D-dimer may help identify HIV-infected patients at elevated CVD risk.

HIV is associated with thrombophilia and high D-dimer in children and adolescents

BACKGROUND AND OBJECTIVE

Atherosclerosis and other cardiovascular diseases associated with thrombosis appear more relevant and anticipated in HIV-infected patients after combination antiretroviral therapy (cART) has reduced AIDS-related diseases and has improved survival. The association between viral replication and coagulation abnormalities in a cohort of HIV-infected children and adolescents was investigated here.

METHODS

Protein S, protein C anticoagulant and antithrombin activity, together with fibrinogen, D-dimer, high-sensitive C-reactive protein and homocysteine were assayed in a cross-sectional study among a cohort of HIV-infected children and adolescents. Results in patients with high viral load (HVL, HIV-RNA > 1000 copies/ml) were compared with those in patients with a lower replication (LVL), adjusting for other demographic, clinical and therapeutic covariates.

RESULTS

Eighty-eight patients (mean age 13.5 years, CD4 30%, 72% with LVL) were enrolled. A prevalence of protein S and protein C deficiency of 51 and 8% was, respectively, found. HVL group compared to LVL showed a significant reduction of protein S, protein C and antithrombin activities, and an increase of D-dimer levels. The independent association of HVL with decreased protein S activity (-11.2%, P = 0.04) and increased D-dimer levels (+0.13 microg/ml, P = 0.004) was confirmed in the multivariate model.

CONCLUSIONS

HIV-infected children and adolescents present high prevalence of thrombophilic abnormalities. The multivariate model confirmed that high viral replication is independently associated with decrease of protein S and increase of D-dimer, suggesting the advantage of suppressive therapy on coagulation homeostasis and the opportunity of an active control of cardiovascular risk factors starting at a younger age.

Elevated osteoprotegerin is associated with abnormal ankle brachial indices in patients infected with HIV: a cross-sectional study

Background

Patients infected with HIV have an increased risk for accelerated atherosclerosis. Elevated levels of osteoprotegerin, an inflammatory cytokine receptor, have been associated with a high incidence of cardiovascular disease (including peripheral arterial disease, or PAD), acute coronary syndrome, and cardiovascular mortality. The objective of this study was to determine whether PAD is prevalent in an HIV-infected population, and to identify an association with HIV-specific and traditional cardiovascular risk factors, as well as levels of osteoprotegerin.

Methods

One hundred and two patients infected with HIV were recruited in a cross-sectional study. To identify the prevalence of PAD, ankle-brachial indices (ABIs) were measured. Four standard ABI categories were utilized: ≤ 0.90 (definite PAD); 0.91-0.99 (borderline); 1.00-1.30 (normal); and >1.30 (high). Medical history and laboratory measurements were obtained to determine possible risk factors associated with PAD in HIV-infected patients.

Results

The prevalence of PAD (ABI ≤ 0.90) in a young HIV-infected population (mean age: 48 years) was 11%. Traditional cardiovascular risk factors, including advanced age and previous cardiovascular history, as well as elevated C-reactive protein levels, were associated with PAD. Compared with patients with normal ABIs, patients with high ABIs had significantly elevated levels of osteoprotegerin [1428.9 (713.1) pg/ml vs. 3088.6 (3565.9) pg/ml, respectively, p = 0.03].

Conclusions

There is a high prevalence of PAD in young HIV-infected patients. A number of traditional cardiovascular risk factors and increased osteoprotegerin concentrations are associated with abnormal ABIs. Thus, early screening and aggressive medical management for PAD may be warranted in HIV-infected patients.

Focus on the heart: alcohol consumption, HIV infection, and cardiovascular disease

With the advent of effective antiretroviral therapy, people infected with HIV have a longer life expectancy and, consequently, are likely to develop other chronic conditions also found in noninfected people, including cardiovascular disease (CVD). Alcohol consumption, which is common among HIV-infected people, may influence the risk of CVD. In noninfected adults, moderate alcohol consumption can reduce the risk of coronary heart disease (CHD), heart attacks, and the most common type of stroke, whereas heavy drinking increases the risk of these cardiovascular events. These relationships can be partially explained by alcohol's effects on various risk factors for CVD, including cholesterol and other lipid levels, diabetes, or blood pressure. In HIV-infected people, both the infection itself and its treatment using combination antiretroviral therapy may contribute to an increased risk of CVD by altering blood lipid levels, inducing inflammation, and impacting blood-clotting processes, all of which can enhance CVD risk. Coinfection with the hepatitis C virus also may exacerbate CVD risk. Excessive alcohol use can further enhance CVD risk in HIV-infected people through either of the mechanisms described above. In addition, excessive alcohol use (as well as HIV infection) promote microbial translocation, the leaking of bacteria or bacterial products from the intestine into the blood stream, where they can induce inflammatory and immune reactions that damage the cardiovascular system.

CKD in HIV-infected patients other than HIV-associated nephropathy

A spectrum of kidney diseases in HIV-infected patients has been reported both before and after the introduction of highly active antiretroviral therapy (HAART). Kidney syndromes affecting HIV-infected patients include CKD as well as proteinuria, nephrotic syndrome, and acute nephritic syndrome. Thrombotic microangiopathy should be considered in patients with kidney disease and typical clinical characteristics. As the HIV-infected population ages, there is increased concern regarding the incidence of vascular and metabolic disease, leading to an increased burden of CKD. Although HIV-associated nephropathy is still the major cause of nephrotic syndrome in HIV-infected patients, immune complex glomerulonephritis (ICGN) still comprises a substantial proportion of the disease burden, especially in people of European origin. Genetic investigations into the underpinnings of the various histologic expressions of HIV-associated kidney disease hold great promise. The single most important diagnostic test to differentiate various forms of kidney disease in HIV-infected patients is a kidney biopsy. The results of treating kidney disease in HIV-infected patients remain unclear, and properly designed randomized controlled trials of the treatment of ICGN with HAART and other approaches are desperately needed.

Atherosclerotic vascular disease in HIV: it is not just antiretroviral therapy that hurts the heart!

PURPOSE OF REVIEW

Although potent combination antiretroviral therapy has heralded an unparalleled improvement in the treatment of HIV-1-infected patients, the now well known metabolic complications of treatment, which include dyslipidemia, insulin resistance and changes in body fat distribution, are thought to contribute to an increased risk of atherosclerotic (cardio)vascular disease. Atherogenic changes in plasma lipids as well as some evidence of increased atherogenesis, however, had already been described in HIV-1-infected patients prior to the availability of combination antiretroviral therapy and even prior to that of suboptimal antiretroviral therapy. In this review, we will summarize the various possible factors and mechanisms involved in atherogenesis in HIV-1-infected individuals, with a focus on those mechanisms related to the infection itself and its immunological consequences.

RECENT FINDINGS

Recent data suggest that a treatment strategy involving repeated cycles of CD4-cell-guided combination antiretroviral therapy interruption is associated with a higher risk of (cardio)vascular disease than continuous treatment aimed at optimal viral suppression.

SUMMARY

Apart from the effects of combination antiretroviral therapy-associated metabolic derangements, HIV-1 infection, directly or indirectly, for instance by being associated with a state of chronic immune activation, may contribute to atherogenesis.

CD4 and Chemokine Receptors on Human Brain Microvascular Endothelial Cells, Implications for Human Immunodeficiency Virus Type 1 Pathogenesis

Central nervous system (CNS) dysfunction is commonly observed in children with human immunodeficiency virus type 1 (HIV-1) infection, but the mechanism(s) whereby HIV-1 causes encephalopathy remains incompletely understood. Human brain microvascular endothelial cells (HBMECs), which constitute the blood-brain barrier, are likely to contribute to HIV-1 encephalopathy, but it is unclear whether HIV-1 receptors (CD4, chemokine receptors) are present on HBMECs. In the present study, the presence of CD4 in six different children was demonstrated. Moreover, the presence of CD4 in situ on brain sections was shown. Distribution of CD4 expression was heterogeneous among microvessels; staining for CD4 was strong in some vessels and absent in other adjacent vessels. CD4 and chemokine coreceptors were found to be functional as intercellular adhesion molecule (ICAM)-1 expression increased upon incubation of HBMECs with activating anti-CD4 and anti-chemokine receptor antibodies. The presence of CD4 and chemokine receptors in human brain endothelium of children may have implications for the pathogenesis of HIV-1 encephalopathy and explain the higher incidence of CNS involvement in HIV-1-infected children as compared to adults.

HIV type 1 infection, and not short-term HAART, induces endothelial dysfunction

OBJECTIVE

Ischemic cardiovascular events increasingly occur during long-lasting HIV infection and are attributed either to the infection itself or to the use of HAART. Endothelial dysfunction and platelet activation are markers of atherosclerosis. Our aim was to assess whether patients with chronic HIV infection present endothelial dysfunction and whether this is the consequence of infection or of HAART.

DESIGN

Fifty-six HIV-infected patients were studied in a retrospective cohort study before and 3, 6, 12 and 24 months after starting HAART with protease inhibitors (n = 28) or nonnucleoside reverse transcriptase inhibitors (n = 28), and compared with 28 age-matched and sex-matched healthy controls, and with 10 naive HIV-infected patients studied at diagnosis and after 12 months of untreated infection.

METHODS

Soluble endothelial and platelet activation markers were measured in plasma by flow cytometry.

RESULTS

Soluble P-selectin, soluble vascular cell adhesion molecule-1, monocyte chemoattractant protein-1 and von Willebrand factor were significantly higher in HIV-infected patients than in healthy controls, whereas soluble CD40 ligand and tissue type plasminogen activator were within normal range. During follow-up, soluble vascular cell adhesion molecule-1, monocyte chemoattractant protein-1 and von Willebrand factor but not soluble P-selectin decreased progressively, without significant differences between protease inhibitors and nonnucleoside reverse transcriptase inhibitors treatment. In naive, untreated patients, increased plasma markers of endothelial dysfunction were confirmed at diagnosis, with no changes upon follow-up.

CONCLUSION

Chronic HIV infection, and not its pharmacological treatment, induces alterations of markers of endothelial function. Short-term treatment with HAART reduces some markers of endothelial dysfunction, with no differences between protease inhibitors and nonnucleoside reverse transcriptase inhibitors.

Thrombotic microangiopathy and other glomerular disorders in the HIV-infected patient

SUMMARY

Various forms of kidney disease have been related directly to human immunodeficiency virus (HIV) viral infection, including HIV-associated nephropathy (HIVAN), immune complex diseases, and thrombotic microangiopathy (TMA). HIVAN and HIV immune complex glomerulonephritides are the most common HIV-specific nephropathies. HIV-associated TMA, although far less common, remains an important consideration. The diagnosis of TMA in HIV, which has a poorly understood pathogenesis, can be suggested by thrombocytopenia, microangiopathic hemolytic anemia, and acute renal failure, but only definitively diagnosed by kidney biopsy. Not surprisingly, the incidence and prevalence of the HIV-specific entities have declined with the advent of highly active antiretroviral therapy. With this decline, however, other glomerular diseases are of increasing importance in this high-risk population. The differential diagnosis of glomerular disease in an HIV-positive patient is therefore broad. Glomerular diseases seen in this population include classic focal segmental glomerulosclerosis, IgA nephropathy, postinfectious glomerulonephritis, hepatitis B- and C-related glomerulonephritides, and membranous nephropathy. In addition, as the HIV-infected population ages, diabetic and hypertensive nephropathies are likely to become more prevalent. With overlapping presentations of these entities, definitive diagnosis often is difficult, necessitating kidney biopsy. As a consequence of establishing an accurate diagnosis, improved patient outcome can best be accomplished through disease-specific intervention.

Chemokine-enhanced chemotaxis of lymphangioleiomyomatosis cells with mutations in the tumor suppressor TSC2 gene

Lymphangioleiomyomatosis (LAM) is characterized by cystic lung destruction caused by LAM cells (smooth-muscle-like cells) that have mutations in the tumor suppressor genes tuberous sclerosis complex (TSC) 1 or 2 and have the capacity to metastasize. Since chemokines and their receptors function in chemotaxis of metastatic cells, we hypothesized that LAM cells may be recruited by chemokine(s) in the lung. Quantification of 25 chemokines in bronchoalveolar lavage fluid from LAM patients and healthy volunteers revealed that concentrations of CCL2, CXCL1, and CXCL5 were significantly higher in samples from LAM patients than those from healthy volunteers. In vitro, CCL2 or MCP-1 induced selective migration of cells, showing loss of heterozygosity of TSC2 from a heterogeneous population of cells grown from explanted LAM lungs. Additionally, the frequencies of single-nucleotide polymorphisms in the CCL2 gene promoter region differed significantly in LAM patients and healthy volunteers (p = 0.018), and one polymorphism was associated significantly more frequently with the decline of lung function. The presence (i.e., potential functionality) of chemokine receptors was evaluated using immunohistochemistry in lung sections from 30 LAM patients. Expression of chemokines and these receptors varied among LAM patients and differed from that seen in some cancers (e.g., breast cancer and melanoma cells). These observations are consistent with the notion that chemokines such as CCL2 may serve to determine mobility and specify the site of metastasis of the LAM cell.

Inflammatory and coagulation biomarkers and mortality in patients with HIV infection

BACKGROUND

In the Strategies for Management of Anti-Retroviral Therapy trial, all-cause mortality was higher for participants randomized to intermittent, CD4-guided antiretroviral treatment (ART) (drug conservation [DC]) than continuous ART (viral suppression [VS]).We hypothesized that increased HIV-RNA levels following ART interruption induced activation of tissue factor pathways, thrombosis, and fibrinolysis.

METHODS AND FINDINGS

Stored samples were used to measure six biomarkers: high sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), amyloid A, amyloid P, D-dimer, and prothrombin fragment 1+2. Two studies were conducted: (1) a nested case-control study for studying biomarker associations with mortality, and (2) a study to compare DC and VS participants for biomarker changes. For (1), markers were determined at study entry and before death (latest level) for 85 deaths and for two controls (n = 170) matched on country, age, sex, and date of randomization. Odds ratios (ORs) were estimated with logistic regression. For each biomarker, each of the three upper quartiles was compared to the lowest quartile. For (2), the biomarkers were assessed for 249 DC and 250 VS participants at study entry and 1 mo following randomization. Higher levels of hsCRP, IL-6, and D-dimer at study entry were significantly associated with an increased risk of all-cause mortality. Unadjusted ORs (highest versus lowest quartile) were 2.0 (95% confidence interval [CI], 1.0-4.1; p = 0.05), 8.3 (95% CI, 3.3-20.8; p < 0.0001), and 12.4 (95% CI, 4.2-37.0; p < 0.0001), respectively. Associations were significant after adjustment, when the DC and VS groups were analyzed separately, and when latest levels were assessed. IL-6 and D-dimer increased at 1 mo by 30% and 16% in the DC group and by 0% and 5% in the VS group (p < 0.0001 for treatment difference for both biomarkers); increases in the DC group were related to HIV-RNA levels at 1 mo (p < 0.0001). In an expanded case-control analysis (four controls per case), the OR (DC/VS) for mortality was reduced from 1.8 (95% CI, 1.1-3.1; p = 0.02) to 1.5 (95% CI, 0.8-2.8) and 1.4 (95% CI, 0.8-2.5) after adjustment for latest levels of IL-6 and D-dimer, respectively.

CONCLUSIONS

IL-6 and D-dimer were strongly related to all-cause mortality. Interrupting ART may further increase the risk of death by raising IL-6 and D-dimer levels. Therapies that reduce the inflammatory response to HIV and decrease IL-6 and D-dimer levels may warrant investigation.

Antiretroviral therapy and the human immunodeficiency virus--improved survival but at what cost?

Patients infected with human immunodeficiency virus are living longer since the introduction of combination antiretroviral therapy more than a decade ago - but at what cost? Highly active antiretroviral therapy has been associated with lipodystrophy and associated metabolic derangements such as dyslipidaemia, insulin resistance and diabetes. These complications are likely to contribute to an increased risk of premature and accelerated atherosclerosis with growing concern about potential cardiovascular consequences.

The roles of HIV-1 proteins and antiretroviral drug therapy in HIV-1-associated endothelial dysfunction

Since the emergence of highly active antiretroviral therapy (HAART), human immunodeficiency virus-1 (HIV-1)-infected patients have demonstrated dramatic decreases in viral burden and opportunistic infections, and an overall increase in life expectancy. Despite these positive HAART-associated outcomes, it has become increasingly clear that HIV-1 patients have an enhanced risk of developing cardiovascular disease over time. Clinical studies are instrumental in our understanding of vascular dysfunction in the context of HIV-1 infection. However, most clinical studies often do not distinguish whether HIV-1 proteins, HAART, or a combination of these 2 factors cause cardiovascular complications. This review seeks to address the roles of both HIV-1 proteins and antiretroviral drugs in the development of endothelial dysfunction because endothelial dysfunction is the hallmark initial step of many cardiovascular diseases. We analyze recent in vitro and in vivo studies examining endothelial toxicity in response to HIV-1 proteins or in response to the various classes of antiretroviral drugs. Furthermore, we discuss the multiple mechanisms by which HIV-1 proteins and HAART injure the vascular endothelium in HIV-1 patients. By understanding the molecular mechanisms of HIV-1 protein- and antiretroviral-induced cardiovascular disease, we may ultimately improve the quality of life of HIV-1 patients through better drug design and the discovery of new pharmacological targets.

Human immunodeficiency virus (HIV) infects human arterial smooth muscle cells in vivo and in vitro: implications for the pathogenesis of HIV-mediated vascular disease

Human immunodeficiency virus (HIV) infection is associated with accelerated atherosclerosis and vasculopathy, although the mechanisms underlying these findings have not been determined. Hypotheses for these observations include: 1) an increase in the prevalence of established cardiac risk factors observed in HIV-infected individuals who are currently experiencing longer life expectancies; 2) the dyslipidemia reported with certain HIV anti-retroviral therapies; and/or 3) the proinflammatory effects of infiltrating HIV-infected monocytes/macrophages. An unexplored possibility is whether HIV itself can infect vascular smooth muscle cells (SMCs) and, by doing so, whether SMCs can accelerate vascular disease. Our studies demonstrate that human SMCs can be infected with HIV both in vivo and in vitro. The HIV protein p24 was detected by fluorescence confocal microscopy in SMCs from tissue sections of human atherosclerotic plaques obtained from HIV-infected individuals. Human SMCs could also be infected in vitro with HIV by a mechanism dependent on CD4, the chemokine receptors CXCR4 or CCR5, and endocytosis, resulting in a marked increase in SMC secretion of the chemokine CCL2/MCP-1, which has been previously shown to be a critical mediator of atherosclerosis. In addition, SMC proliferation appeared concentric to the vessel lumen, and minimal inflammation was detected, unlike typical atherosclerosis. Our data suggest that direct infection of human arterial SMCs by HIV represents a potential mechanism in a multifactorial paradigm to explain the exacerbated atherosclerosis and vasculopathy reported in individuals infected with HIV.

Therapy insight: Body-shape changes and metabolic complications associated with HIV and highly active antiretroviral therapy

Increasingly effective therapies for HIV infection are now available. These treatments, referred to collectively as highly active antiretroviral therapy, comprise various combinations of anti-HIV drugs from different drug classes. Recently, a range of metabolic complications have emerged as important toxicities in treated patients. Complications present as abnormalities of body-fat mass distribution in association with an often significant dyslipidemia and glucose homeostasis dysregulation. The body-shape changes, manifesting as peripheral lipoatrophy or central lipohypertrophy, can have a negative impact on quality of life and consequently on adherence to treatment. The combination of central lipohypertrophy, dyslipidemia and insulin resistance is associated with accelerated rates of atherosclerosis and other potentially significant long-term effects. The pathogenesis of these effects is complex and is still being actively investigated. Possible contributing factors relate to host characteristics, HIV viral parameters and specific effects of anti-HIV drugs on adipose-tissue biology and on intermediary metabolism. Management of these complications involves manipulation of the anti-HIV drugs using an understanding of their particular effects on lipid and glucose metabolism, in association with standard therapeutic interventions. Individualized approaches, taking into consideration quality-of-life issues, and assessment of potential cardiovascular risks, are now an important component of effective care of HIV-infected patients.

The Role of Immunity and Inflammation in the Progression of Atherosclerosis in Patients With HIV Infection

Background and Purpose— The initial steps of atherosclerosis and the entry of HIV into the cell share similar biological mechanisms. Therefore, our hypothesis is that the progression of atherosclerosis in patients with HIV infection can be influenced by variations in genes implicated in both processes.

Methods and Results— The progression of atherosclerosis over a 2-year follow-up period was measured as the combined carotid and femoral intima media thickness (IMT) in 141 patients with HIV infection. The ΔIMT (IMT follow-up −IMT baseline ) values were used to segregate patients as minimal progressors or regressors (lowest ΔIMT tertile), slow progressors (mid ΔIMT tertile), and rapid progressors (highest ΔIMT tertile). Mutations CCR-5Δ32, CCR-2 64I, MCP-1-2518G, SDF1-3′A, and CX3CR-1 (T280 mol/L and V249I) in the host DNA were determined. Mean age of the patients was 38.96 (SEM: 0.61) and 68.8% were male. The mean ΔIMT was 0.045 mm (0.01) per year, which represented a significant progression ( P <0.001) with respect to baseline values. Patients with minimal progression or regression had a significantly ( P =0.01) higher CD4 cell count than slow progressors and rapid progressors. Multivariate analyses indicated that age and total cholesterol were positively associated with IMT progression. In contrast, the CD4 cell count, the SDF1-3′A, and the CX3CR-1 249 I mutated alleles were associated with lesser IMT progression.

Conclusion— The course of atherosclerosis in patients with HIV infection is influenced by polymorphisms in the SDF1 and CX3CR1 genes by metabolic variables and by the CD4 cell count. These data would be of help in assessing therapeutic needs of these patients.

Differential role of reactive oxygen species in the activation of mitogen-activated protein kinases and Akt by key receptors on B-lymphocytes: CD40, the B cell antigen receptor, and CXCR4

BACKGROUND

Antibodies produced by B-lymphocytes play a key role in the host defense against infection. The development, survival, and activation of B cell is regulated by multiple receptors including the B cell antigen receptor (BCR), which detects the presence of pathogens, CD40, which binds co-stimulatory molecules on activated T cells, and chemokines such as SDF-1 (CXCL12) that play key roles in B cell development and trafficking. Signaling by many receptors results in the generation of reactive oxygen species (ROS) that function as second messengers by regulating the activity of redox-sensitive kinases and phosphatases. We investigated the role of ROS in signaling by the BCR, CD40, and CXCR4, the receptor for SDF-1. We focused on activation of ERK, JNK, p38, and Akt, kinases that regulate multiple processes including cell survival, proliferation, and migration.

RESULTS

Using the anti-oxidants N-acetyl L-cysteine (NAC) and ebselen to deplete intracellular ROS, we identified a differential requirement for ROS in the activation of ERK, JNK, p38, and Akt by these receptors. We found that CD40 activated JNK, p38, and Akt via redox-dependent pathways that were sensitive to ROS depletion by NAC and ebselen. In contrast, BCR-induced activation of ERK, JNK, p38, and Akt was not affected by ROS depletion. We also found that CXCR4-induced Akt activation was ROS-dependent even though activation of the ERK, JNK, and p38 MAP kinases by CXCR4 occurred via ROS-independent pathways.

CONCLUSION

The differential requirement for ROS in the activation of ERK, JNK, p38, and Akt by the BCR, CD40, and CXCR4 likely reflects the multiplicity of upstream activators for each of these kinases, only some of which may be regulated in a redox-dependent manner. These findings support the idea that ROS are important second messengers in B cells and suggest that oxidants or anti-oxidants could be used to modulate B cell activation.

Current Update on HIV-associated Vascular Disease and Endothelial Dysfunction

Highly active antiretroviral therapy (HAART) has greatly reduced the risk of early death from opportunistic infections and extended the lifespan of people infected with the human immunodeficiency virus (HIV). Thus, many complications and organic damage in the HIV-infected population emerge. Cardiovascular disease as coronary artery disease has become a matter of particular concern. Its incidence is greatly increased in the HIV-infected population over that of people of the same age in the absence of general cardiovascular risk factors. Despite several clinical and laboratory studies in the association between HIV infection and cardiovascular disease, the pathogenic mechanisms of this significant clinical problem are largely unknown and are now under active investigation. Endothelial dysfunction is possibly the most plausible link between HIV infection and atherosclerosis. Increased expression of adhesion molecules such as intercellular adhesion molecule (ICAM)-1 and endothelial adhesion molecule (E-selectin) and inflammatory cytokines such as tumor necrosis factor (TNF)-alpha and interleukin (IL-6 has been reported in HIV-positive patients. The effect of HAART on endothelial function in HIV-positive patients is also demonstrated. In this review, we focus on the recent research update of HIV-associated vascular disease and vascular injury. We analyze and discuss the recent clinical and laboratory investigations on the effect of HIV, viral protein, and HAART therapy on endothelial injury and vascular disease; identify the areas of controversy and clinical relevance; and suggest some directions for future research.