Mechanisms of Cardiovascular Disease in the Setting of HIV Infection

Although the initial reports of increased cardiovascular (CV) disease in the setting of advanced AIDS were reported approximately 30 years ago, advances in antiretroviral therapy and immediate initiation of therapy on diagnosis have transformed what was once a deadly infectious disease into a chronic health condition. Accordingly, the types of CV diseases occurring in HIV have shifted from pericardial effusions and dilated cardiomyopathy to atherosclerosis and heart failure. The underlying pathophysiology of HIV-associated CV disease remains poorly understood, partly because of the rapidly evolving nature of HIV treatment and because clinical endpoints take many years to develop. The gut plays an important role in the early pathogenesis of HIV infection as HIV preferentially infects CD4+ T cells, 80% of which are located in gut mucosa. The loss of these T cells damages gut mucosa resulting in increased gut permeability and microbial translocation, which incites chronic inflammation and immune activation. Antiretroviral therapy does not cure HIV infection and immune abnormalities persist. These abnormalities correlate with mortality and CV events. The effects of antiretroviral therapy on CV risk are complex; treatment reduces inflammation and other markers of CV risk but induces lipid abnormalities, most commonly hypertriglyceridemia. On a molecular level, monocytes/macrophages, platelet reactivity, and immune cell activation, which play a role in the general population, may be heightened in the setting of HIV and contribute to HIV-associated atherosclerosis. Chronic inflammation represents an inviting therapeutic target in HIV, as it does in uninfected persons with atherosclerosis.     

Immune activation and chronic inflammation: Is there an additional effect of HIV in a geriatric population?

HIV infection has become a chronic disease, with a lower mortality, but a consequent increase in age-related noninfectious comorbidities. Metabolic disorders have been linked to the effect of cART as well to the effects of immune activation and chronic inflammation. Whereas it is known that aging is intrinsically associated with hyperinflammation and immune system deterioration, the relative impact of chronic HIV infection on such inflammatory and immune activation has not yet been studied focusing on an elderly HIV-infected population.The objectives of the study were to assess 29 blood markers of immune activation and inflammation using an ultrasensitive technique, in HIV-infected patients aged ≥75 years with no or 1 comorbidity (among hypertension, renal disease, neoplasia, diabetes mellitus, cardiovascular disease, stroke, dyslipidemia, and osteoporosis), in comparison with age-adjusted HIV-uninfected individuals to identify whether biomarkers were associated with comorbidities. Wilcoxon nonparametric tests were used to compare the levels of each marker between control and HIV groups; logistic regression to identify biomarkers associated to comorbidity in the HIV group and principal component analysis (PCA) to determine clusters associated with a group or a specific comorbidity.A total of 111 HIV-infected subjects were included from the Dat’AIDS cohort and compared to 63 HIV-uninfected controls. In the HIV-infected group, 4 biomarkers were associated with the risk of developing a comorbidity: monocyte chemoattractant protein-1 (MCP-1), neurofilament light chain (NF-L), neopterin, and soluble CD14. Six biomarkers (interleukin [IL]-1B, IL-7, IL-18, neopterin, sCD14, and fatty acid-binding protein) were significantly higher in the HIV-infected group compared to the control group, 11 biomarkers (myeloperoxydase, interleukin-1 receptor antagonist, tumor necrosis factor receptor 1, interferon-gamma, MCP-1, tumor necrosis factor receptor 2, IL-22, ultra sensitivity C-reactive protein, fibrinogen, IL-6, and NF-L) were lower. Despite those differences, PCA to determine clusters associated with a group or a specific comorbidity did not reveal clustering nor between healthy control and HIV-infected patients neither between the presence of comorbidity within HIV-infected group.In this highly selected geriatric HIV population, HIV infection does not seem to have an additional impact on age-related inflammation and immune disorder. Close monitoring could have led to optimize prevention and treatment of comorbidities, and have limited both immune activation and inflammation in the aging HIV population.     

Overcoming depression

Depression is one of the most prevalent and undertreated complications of HIV disease. Despite the improvements in health related to highly active antiretroviral therapy (HAART), women and men with HIV continue to be at risk for depression. Untreated depression not only can affect quality of life, but it also may compromise HAART adherence, weaken immune functioning, exacerbate chronic pain, and contribute to substance use. Depression might also lead to sexual risk-taking behavior in some people with HIV, potentially contributing to HIV transmission. This article will address a range of questions concerning HIV-related depression. Why is depression so common in people with HIV? Is it seen more frequently in those with HIV disease than in uninfected individuals? If so, why? And if depression is so common, why is it typically overlooked by HIV clinicians? Finally, is depression treated differently in people with HIV, and what specific types of therapy or medications are most useful?     

HIV and COPD: a conspiracy of risk factors

Chronic obstructive pulmonary disease (COPD) is an under recognized complication of HIV infection. It is estimated that up to 25% of HIV infected people may have COPD. HIV is associated with COPD as a result of a complex interplay of multiple factors such as pulmonary inflammation, recurrent pulmonary infections especially tuberculosis (TB), increased cigarette smoking, socio‐economic status, childhood respiratory illnesses and industrial and environmental exposures; each of which are risk factors for COPD in their own right. COPD presents at an earlier age in people with HIV infection. There are over 35 million people living with HIV, and most people infected with HIV live in developing regions of the world where they are faced with multiple risk factors for COPD and suboptimal access to health care. TB is the commonest infectious complication of HIV, and HIV infected persons often experience multiple episodes of TB. Cigarette smoking is increasing in developing countries where the greatest burden of TB and HIV is experienced. Cigarette smoking is associated with increased risk of TB and may be associated with acquisition of HIV infection and progression. It is not clear whether non‐infectious pulmonary inflammation persists in the lung when immune reconstitution occurs. Prevention and control of HIV infection must be part of the multiple interventions to reduce the global burden of COPD. A multidisciplinary approach, including behavioural science is required to address this challenge. It presents research opportunities that should be driven by the pulmonology community.     

Coronary Artery Disease Manifestations in HIV: What,How, and Why

Understanding why persons with human immunodeficiency virus (HIV) have accelerated atherosclerosis and its sequelae, including coronary artery disease (CAD) and myocardial infarction, is necessary to provide appropriate care to a large and aging population with HIV. In this review, we delineate the diverse pathophysiologies underlying HIV-associated CAD and discuss how these are implicated in the clinical manifestations of CAD among persons with HIV. Several factors contribute to HIV-associated CAD, with chronic inflammation and immune activation likely representing the primary drivers. Increased monocyte activation, inflammation, and hyperlipidemia present in chronic HIV infection also mirror the pathophysiology of plaque rupture. Furthermore, mechanisms central to plaque erosion, such as activation of toll-like receptor 2 and formation of neutrophil extracellular traps, are also abundant in HIV. In addition to inflammation and immune activation in general, persons with HIV have a higher prevalence than uninfected persons of traditional cardiovascular risk factors, including dyslipidemia, hypertension, insulin resistance, and tobacco use. Antiretroviral therapies, although clearly necessary for HIV treatment and survival, have had varied effects on CAD, but newer generation regimens have reduced cardiovascular toxicities. From a clinical standpoint, this mix of risk factors is implicated in earlier CAD among persons with HIV than uninfected persons; whether the distribution and underlying plaque content of CAD for persons with HIV differs considerably from uninfected persons has not been definitively studied. Furthermore, the role of cardiovascular risk estimators in HIV remains unclear, as does the role of traditional and emerging therapies; no trials of CAD therapies powered to detect clinical events have been completed among persons with HIV.     

Enteropathies in the developing world: neglected effects on global health

A spectrum of enteropathies, characterized by small intestinal inflammation, reduced absorptive capacity, and increased intestinal permeability, commonly affect people in developing countries. This subclinical intestinal pathology facilitates microbial translocation across the compromised intestinal barrier, leading to chronic systemic inflammation that may adversely impact health. Environmental enteropathy (EE), ubiquitous among people living in unhygienic conditions, likely mediates two interlinked public health problems of childhood, stunting and anemia, and underlies poor oral vaccine efficacy in developing countries. Human immunodeficiency virus (HIV) enteropathy, which frequently overlaps with EE, may contribute to immune activation and modulate HIV disease progression. The interacting effects of infection and enteropathy drive a vicious cycle that can propagate severe acute malnutrition, which underlies almost half of under-5-y deaths. Enteropathies are therefore highly prevalent, interacting causes of morbidity and mortality in developing countries. Interventions to prevent or ameliorate enteropathies have potential to improve the health of millions of people in developing countries.     

Microbial translocation,residual viremia and immune senescence in the pathogenesis of HIV-1 infection

The pathophysiological mechanisms that underlie the progression of human immunodeficiency virus-1 (HIV-1) disease to full-blown AIDS are not well understood. Findings suggest that, during HIV-1 infection, plasma lipopolysaccharide (LPS) levels, which are used as an indicator of microbial translocation (MT), are elevated throughout the acute and chronic phases of HIV-1 disease. The translocation of bacterial products through the damaged gastrointestinal barrier into the systemic circulation has been described as a driver of immune activation. In contrast, comorbidities that are associated with HIV-1 infection have been attributed to chronic inflammation and immune system dysfunction secondary to MT or low-level HIV-1 replication in plasma and cell reservoirs. Moreover, accelerated aging is significantly associated with chronic inflammation, immune activation, and immune senescence. In this review, we aimed to investigate the role of inflammation as a pivotal marker in the pathogenesis of HIV-1 disease. We will discuss the key features of chronic inflammation and immune activation that are observed during the natural course of the disease and those features that are detected in cART-modified infection. The review will focus on the following aspects of HIV-1 infection: (1) MT; (2) the role of residual viremia; and (3) “immune senescence” or “inflammaging.” Many questions remain unanswered about the potential mechanisms that are involved in HIV-1 pathogenesis. Further studies are needed to better investigate the mechanisms that underlie immune activation and their correlation with HIV-1 disease progression.     

Immune activation and neuroinflammation in alcohol use and HIV infection: evidence for shared mechanisms

Background: Emerging research points to innate immune mechanisms in the neuropathological and behavioral consequences of heavy alcohol use. Alcohol use is common among people living with HIV infection (PLWH), a chronic condition that carries its own set of long-term effects on brain and behavior. Notably, neurobiological and cognitive profiles associated with heavy alcohol use and HIV infection share several prominent features. This observation raises questions about interacting biological mechanisms as well as compounded impairment when HIV infection and heavy drinking co-occur. Objective and Method: This narrative overview discusses peer-reviewed research on specific immune mechanisms of alcohol that exhibit apparent potential to compound the neurobiological and psychiatric sequelae of HIV infection. These include microbial translocation, systemic immune activation, blood-brain barrier compromise, microglial activation, and neuroinflammation. Results: Clinical and preclinical evidence supports overlapping mechanistic actions of HIV and alcohol use on peripheral and neural immune systems. In preclinical studies, innate immune signaling mediates many of the detrimental neurocognitive and behavioral effects of alcohol use. Neuropsychopharmacological research suggests potential for a feed-forward cycle in which heavy drinking induces innate immune signaling, which in turn stimulates subsequent alcohol use behavior. Conclusion: Alcohol-induced immune activation and neuroinflammation are a serious health concern for PLWH. Future research to investigate specific immune effects of alcohol in the context of HIV infection has potential to identify novel targets for therapeutic intervention.     

Immunologic basis of cardiovascular disease in HIV-infected adults

Cardiovascular complications are more common in human immunodeficiency virus-infected individuals than in age-matched uninfected individuals. Antiretroviral therapy reduces the risk of cardiovascular complications, suggesting that viral replication directly or indirectly causes vascular disease. Long-term effective antiretroviral therapy does not fully restore vascular health, and treated adults continue to have higher-than-expected rates of disease progression. Although this excess risk during therapy is likely due to multiple factors, a growing body of evidence suggests that chronic inflammation, which persists during effective antiretroviral therapy, is directly and causally associated with vascular dysfunction and the accelerated development of atherosclerosis.     

Treatment of SIV-infected sooty mangabeys with a type-I IFN agonist results in decreased virus replication without inducing hyperimmune activation

A key feature differentiating nonpathogenic SIV infection of sooty mangabeys (SMs) from pathogenic HIV/SIV infections is the rapid resolution of type I IFN (IFN-I) responses and IFN-stimulated gene expression during the acute-to-chronic phase transition and the establishment of an immune quiescent state that persists throughout the chronic infection. We hypothesized that low levels of IFN-I signaling may help to prevent chronic immune activation and disease progression in SIV-infected SMs. To assess the effects of IFN-I signaling in this setting, in the present study, we administered recombinant rhesus macaque IFNα2-IgFc (rmIFNα2) to 8 naturally SIV-infected SMs weekly for 16 weeks. Gene-expression profiling revealed a strong up-regulation of IFN-stimulated genes in the blood of treated animals, confirming the reagent's bioactivity. Interestingly, we observed an approximately 1-log decrease in viral load that persisted through day 35 of treatment. Flow cytometric analysis of lymphocytes in the blood, lymph nodes, and rectal biopsies did not reveal a significant decline of CD4(+) T cells, a robust increase in lymphocyte activation, or change in the level of SIV-specific CD8(+) T cells. The results of the present study indicate that administration of type I IFNs in SIV-infected SMs induces a significant anti-viral effect that is not associated with a detectable increase in chronic immune activation.     

Clinical relevance of endoscopic assessment of inflammation in ulcerative colitis: Can endoscopic evaluation predict outcomes?

Ulcerative colitis(UC) is a chronic inflammatory bowel condition characterised by a relapsing and remitting course. Symptom control has been the traditional mainstay of medical treatment. It is well known that histological inflammatory activity persists despite adequate symptom control and absence of endoscopic inflammation. Current evidence suggests that presence of histological inflammation poses a greater risk of disease relapse and subsequent colorectal cancer risk. New endoscopic technologies hold promise for developing endoscopic markers of mucosal inflammation. Achieving endoscopic and histological remission appears be the future aim of medical treatments for UC. This review article aims to evaluate the use of endoscopy as a tool in assessment of mucosal inflammation UC and its correlation with disease outcomes.     

Hypertension Is a Key Feature of the Metabolic Syndrome in Subjects Aging with HIV

With widespread and effective antiretroviral therapy, the life expectancy in the HIV population has dramatically improved over the last two decades. Consequently, as patients are aging with HIV, other age-related comorbidities, such as metabolic disturbances and cardiovascular disease (CVD), have emerged as important causes of morbidity and mortality. An overrepresentation of traditional cardiovascular risk factors (RF), toxicities associated with long exposure to antiretroviral therapy, together with residual chronic inflammation and immune activation associated with HIV infection are thought to predispose to these metabolic complications and to the excess risk of CVD observed in the HIV population. The metabolic syndrome (MS) represents a clustering of RF for CVD that includes abdominal obesity, hypertension, dyslipidemia and insulin resistance. Hypertension is a prevalent feature of the MS in HIV, in particular in the aging population, and constitutes an important RF for CVD. Physicians should screen their patients for metabolic and cardiovascular risk at the regular visits to reduce MS and the associated CVD risk among people aging with HIV, since many of RF are under-diagnosed and under-treated conditions. Interventions to reduce these RF can include lifestyle changes and pharmacological interventions such as antihypertensive and lipid-lowering therapy, and treatment of glucose metabolism disturbances. Changes in antiretroviral therapy to more metabolic neutral antiretroviral drugs may also be considered.     

Downregulation of CD38 activation markers by atorvastatin in HIV patients with undetectable viral load

Immune activation and chronic inflammation are recognized as major component of HIV disease even in patients with undetectable viral load. We evaluated the effect of atorvastatin on CD38 activation in such patients, in a case-control study (133 cases - 266 controls). At week 48, CD38 activation was significantly lower in cases vs. controls, with no difference in high-sensitivity C-reactive protein (hsCRP) and CD4. These results suggest that atorvastatin reduces the level of immune activation in patients with undetectable viral load.     

Inflammation and Cardiovascular Disease Risk: A Case Study of HIV and Inflammatory Joint Disease

The epidemiologic data associating infection and inflammation with increased risk of cardiovascular disease is well established. Patients with chronically upregulated inflammatory pathways, such as those with HIV and inflammatory joint diseases, often have a risk of future cardiovascular risk that is similar to or higher than patients with diabetes. Thus, it is of heightened importance for clinicians to consider the cardiovascular risk of patients with these conditions. HIV and inflammatory joint diseases are archetypal examples of how inflammatory disorders contribute to vascular disease and provide illustrative lessons that can be leveraged in the prevention of cardiovascular disease. Managing chronic inflammatory diseases calls for a multifaceted approach to evaluation and treatment of suboptimal lifestyle habits, accurate estimation of cardiovascular disease risk with potential upwards recalibration due to chronic inflammation, and more intensive treatment of risk factors because current tools often underestimate the risk in this population. This approach is further supported by the recently published CANTOS trial demonstrating that reducing inflammation can serve as a therapeutic target among persons with residual inflammatory risk for cardiovascular disease.     

The Spectrum of Atherosclerotic Coronary Artery Disease in HIV Patients

The incidence of HIV is on the rise. With the advent of antiretroviral therapy, the average life expectancy of HIV patients has increased by several decades, but the increasing life expectancy has shifted the spectrum of HIV-associated morbidity and mortality away from opportunistic infections and toward chronic medical conditions. In fact, coronary artery disease has become the leading cause of mortality in patients with HIV. The pathophysiology of atherosclerosis in patients with HIV is very complex, including direct endothelial damage from viremia, a heightened overall state of inflammation from immune activation, higher prevalence and contribution from traditional atherosclerotic risk factors, and direct effects from antiretroviral therapy itself. This review focuses on the patterns, predictors, and pathophysiology of atherosclerotic disease in patients with HIV. In addition, the risks and benefits of evidence-based highly active antiretroviral therapy are critically evaluated.     

CD4+ T cell depletion in human immunodeficiency virus (HIV) infection: role of apoptosis

Human immunodeficiency virus (HIV) infection is principally a mucosal disease and the gastrointestinal (GI) tract is the major site of HIV replication. Loss of CD4+ T cells and systemic immune hyperactivation are the hallmarks of HIV infection. The end of acute infection is associated with the emergence of specific CD4+ and CD8+ T cell responses and the establishment of a chronic phase of infection. Abnormal levels of immune activation and inflammation persist despite a low steady state level of viremia. Although the causes of persistent immune hyperactivation remain incompletely characterized, physiological alterations of gastrointestinal tract probably play a major role. Failure to restore Th17 cells in gut-associated lymphoid tissues (GALT) might impair the recovery of the gut mucosal barrier. This review discusses recent advances on understanding the contribution of CD4+ T cell depletion to HIV pathogenesis.     

Atherosclerosis and systemic lupus erythematosus

Large increases in mortality related to premature atherosclerosis with coronary artery disease have been reported in patients with systemic lupus erythematosus (SLE). The current pathogenic hypothesis for atherosclerosis involves not only the classic factors identified in the Framingham study, but also includes chronic inflammation, corticosteroid therapy, excess of traditional risk factors, autoantibodies, immune complexes (containing antibodies to phospholipids, to oxidized low-density lipoproteins, and to endothelial cells), and cytokine-producing activated T cells. Early risk factor intervention and effective control of inflammation should be incorporated into the management of SLE to protect against atherosclerosis.     

Relationship between residual plasma viremia and the size of HIV proviral DNA reservoirs in infected individuals receiving effective antiretroviral therapy

Residual plasma viremia (<50 copies/mL) persists in certain human immunodeficiency virus (HIV)-infected individuals receiving antiretroviral therapy (ART); however, the relationship between the degree of residual plasma viremia, the size of HIV reservoirs, and the level of immune activation has not been delineated. Here, we demonstrate that residual plasma viremia correlates with the size of the CD4(+) T cell viral reservoir, but not with markers of immune activation, suggesting that reactivation of the latent viral reservoir may not be the sole source of residual plasma viremia. Novel therapeutic strategies aimed at targeting the source of residual viremia may be necessary to achieve viral eradication.     

Granulomatöse Lungen- und Systemerkrankungen

Granuloma formation occurs in the human body if there is a particle which persists in phagocytes and which the immune system cannot eliminate. The immune reaction of granuloma formation evolved in order to combat mycobacteria with the aim of localizing mycobacteria and to avoid spreading of mycobacteria throughout the body. Granulomatous lung diseases are often accompanied by severe, systemic inflammation. However, acute phase proteins may be only slightly elevated. The spectrum of granulomatous lung diseases is broad. Sarcoidosis is the most common granulomatous lung disease. To diagnose sarcoidosis, other infectious granulomatous lung diseases such as tuberculosis, atypical mycobacterial and fungal infection have to be ruled out. Pulmonary granuloma also evolve in the context of autoimmune diseases such as rheumatoid arthritis, granulomatosis with polyangiitis (GBA, Wegener’s) and eosinophilic granulomatosis with polyangiitis (EGPA, Churg–Strauss syndrome). Furthermore, immunodeficiencies such as common variable immunodeficiency (CVID) and immune reconstitution syndrome in HIV can be associated with systemic granulomatous inflammation. Finally, occupational lung disease, particularly hypersensitivity pneumonitis, silicosis, hard metal lung, and chronic berylliosis are associated with pulmonary granuloma formation.