Cardiovascular complications of AIDS. Curr Opin Crit Care. 2010;16:408-412. [PMID: 20689417 DOI: 10.1097/mcc.0b013e32833e10a9]

[Cardiovascular compromise in the infection by the human immunodeficiency virus]

Human immunodeficiency virus (HIV) infection was associated with increased morbidity and mortality, predominantly for opportunistic infections, before using antiretroviral therapy. With this, patients have experienced increased survival and cardiovascular compromise too. The etiology of these clinical conditions could be related to the infection itself, adverse events associated with antiretroviral therapy, or adverse events produced by the combination with other drugs. Some of these conditions have an acute onset, and their rapid recognition is vital for a better prognosis.

HIV-related cardiovascular diseases: the search for a unifying hypothesis

Although the extensive rollout of antiretroviral (ARV) therapy resulted in a longer life expectancy for people living with human immunodeficiency virus (PLHIV), such individuals display a relatively increased occurrence of cardiovascular diseases (CVD). This health challenge stimulated significant research interests in the field, leading to an improved understanding of both lifestyle-related risk factors and the underlying mechanisms of CVD onset in PLHIV. However, despite such progress, the precise role of various risk factors and mechanisms underlying the development of HIV-mediated CVD still remains relatively poorly understood. Therefore, we review CVD onset in PLHIV and focus on 1) the spectrum of cardiovascular complications that typically manifest in such persons and 2) underlying mechanisms that are implicated in this process. Here, the contributions of such factors and modulators and underlying mechanisms are considered in a holistic and integrative manner to generate a unifying hypothesis that includes identification of the core pathways mediating CVD onset. The review focuses on the sub-Saharan African context, as there are relatively high numbers of PLHIV residing within this region, indicating that the greater CVD risk will increasingly threaten the well-being and health of its citizens. It is our opinion that such an approach helps point the way for future research efforts to improve treatment strategies and/or lifestyle-related modifications for PLHIV.

Targeted editing of the PSIP1 gene encoding LEDGF/p75 protects cells against HIV infection

To fulfill a productive infection cycle the human immunodeficiency virus (HIV) relies on host-cell factors. Interference with these co-factors holds great promise in protecting cells against HIV infection. LEDGF/p75, encoded by the PSIP1 gene, is used by the integrase (IN) protein in the pre-integration complex of HIV to bind host-cell chromatin facilitating proviral integration. LEDGF/p75 depletion results in defective HIV replication. However, as part of its cellular function LEDGF/p75 tethers cellular proteins to the host-cell genome. We used site-specific editing of the PSIP1 locus using CRISPR/Cas to target the aspartic acid residue in position 366 and mutated it to asparagine (D366N) to disrupt the interaction with HIV IN but retain LEDGF/p75 cellular function. The resulting cell lines demonstrated successful disruption of the LEDGF/p75 HIV-IN interface without affecting interaction with cellular binding partners. In line with LEDGF/p75 depleted cells, D366N cells did not support HIV replication, in part due to decreased integration efficiency. In addition, we confirm the remaining integrated provirus is more silent. Taken together, these results support the potential of site-directed CRISPR/Cas9 mediated knock-in to render cells more resistant to HIV infection and provides an additional strategy to protect patient-derived T-cells against HIV-1 infection as part of cell-based therapy.

The involvement of plasmacytoid cells in HIV infection and pathogenesis

Plasmacytoid dendritic cells (pDCs) are a unique dendritic cell subset that are specialized in type I interferon (IFN) production. pDCs are key players in the antiviral immune response and serve as bridge between innate and adaptive immunity. Although pDCs do not represent the main reservoir of the Human Immunodeficiency Virus (HIV), they are a crucial subset in HIV infection as they influence viral transmission, target cell infection and antigen presentation. pDCs act as inflammatory and immunosuppressive cells, thus contributing to HIV disease progression. This review provides a state of art analysis of the interactions between HIV and pDCs and their potential roles in HIV transmission, chronic immune activation and immunosuppression. A thorough understanding of the roles of pDCs in HIV infection will help to improve therapeutic strategies to fight HIV infection, and will further increase our knowledge on this important immune cell subset.

Sex and gender differences in HIV-1 infection

The major burden of the human immunodeficiency (HIV) type 1 pandemic is nowadays carried by women from sub-Saharan Africa. Differences in the manifestations of HIV-1 infection between women and men have been long reported, and might be due to both socio-economic (gender) and biological (sex) factors. Several studies have shown that women are more susceptible to HIV-1 acquisition than men. Following HIV-1 infection, women have lower viral loads during acute infection and exhibit stronger antiviral responses than men, which may contribute to differences in the size of viral reservoirs. Oestrogen receptor signalling could represent an important mediator of sex differences in HIV-1 reservoir size and may represent a potential therapeutic target. Furthermore, immune activation, a hallmark of HIV-1 infection, is generally higher in women than in men and could be a central mechanism in the sex difference observed in the speed of HIV-1 disease progression. Here, we review the literature regarding sex-based differences in HIV-1 infection and discuss how a better understanding of the underlying mechanisms could improve preventive and therapeutic strategies.

HIV-1 and hijacking of the host immune system: the current scenario

Human immunodeficiency virus (HIV) infection is a major health burden across the world which leads to the development of acquired immune deficiency syndrome (AIDS). This review article discusses the prevalence of HIV, its major routes of transmission, natural immunity, and evasion from the host immune system. HIV is mostly prevalent in Sub-Saharan Africa and low income countries. It is mostly transmitted by sharing syringe needles, blood transfusion, and sexual routes. The host immune system is categorized into three main types; the innate, the adaptive, and the intrinsic immune system. Regarding the innate immune system against HIV, the key players are mucosal membrane, dendritic cells (DCs), complement system, interferon, and host Micro RNAs. The major components of the adaptive immune system exploited by HIV are T cells mainly CD4+ T cells and B cells. The intrinsic immune system confronted by HIV involves (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G) APOBEC3G, tripartite motif 5-α (TRIM5a), terherin, and (SAM-domain HD-domain containing protein) SAMHD1. HIV-1 efficiently interacts with the host immune system, exploits the host machinery, successfully replicates and transmits from one cell to another. Further research is required to explore evasion strategies of HIV to develop novel therapeutic approaches against HIV.

Myocardial deformation imaging unmasks subtle left ventricular systolic dysfunction in asymptomatic and treatment-naïve HIV patients

BACKGROUND

Patients infected by the human immunodeficiency virus (HIV) and receiving highly active antiretroviral therapy have a higher incidence of cardiovascular disease than healthy subjects, but little is known about cardiac function in asymptomatic and treatment-naïve patients. We sought to study cardiac function in asymptomatic HIV-infected, treatment-naïve patients.

METHODS

We studied 41 HIV-infected and treatment-naïve patients and 20 age- and sex-matched healthy controls. Patients with cardiac symptoms, history of cardiac disease or NT-proBNP >100 pg/mL were excluded. We addressed cardiac function using standard echocardiography along with tissue Doppler (TDI) measurements, including strain/strain rate assessment.

RESULTS

Standard echocardiographic parameters did not differ between groups, except for transmitral E wave velocity (64.8 ± 14 cm/s in HIV vs 76.1 ± 10 cm/s in controls, p = 0.002). In contrast, TDI mitral and tricuspid annulus s velocity and all strain/strain rate measurements were significantly lower in HIV patients: s lateral, 10.2 ± 2.4/11.3 ± 0.7, p = 0.011; s septal, 8.1 ± 1.6/8.7 ± 0.8, p = 0.045; s tricuspid, 13.4 ± 2.3/14.9 ± 1.3, p = 0.002; strain/strain rate, septal (strain/strain rate, 15.1 ± 5.7/-0.9 ± 0.3, 25.3 ± 1.7/-1.9 ± 0.2, p < 0.001), anterior (16.7 ± 3/-1.0 ± 0.1, 26.7 ± 1.7/-1.9 ± 0.2, p < 0.001), lateral (16.0 ± 6/-1.0 ± 0.1, 27.5 ± 1.8/-2.2 ± 0.3, p < 0.001) and posterior (15.2 ± 5.8/-1.0 ± 0.2, 26.2 ± 1.8/-2.2 ± 0.3, p < 0.001) left ventricular wall.

CONCLUSIONS

HIV infection itself is accompanied by subclinical systolic dysfunction, not apparent to standard echocardiography that can be unmasked though using sensitive echocardiographic techniques.

Cardiovascular disease in human immunodeficiency virus-infection as a cause of hospitalization: a case-series in a General Hospital in Peru

Background

Cardiovascular disease in the context of human immunodeficiency virus infection has become a major clinical concern in recent years. In the current report we assess hospitalizations due to cardiovascular disease in human immunodeficiency virus patients in a Social Security reference hospital in Peru.

Methods

A retrospective study was carried out between January 1996 and December 2012 in a General Hospital in Lima, Peru.

Results

We included 26 patients hospitalized due to cardiovascular disease. Mean age was 46.3 years (SD 12.5), predominantly male (57.7%). Ten patients (38.4%) were in Acquired Immunodeficiency Syndrome stages. Seventeen (65.4%) received high-active-antiretroviral therapy. Eleven (42.3%) had cardiac involvement and 15 (57.7%) had non-cardiac vascular involvement. The most frequent causes of cardiac involvement were pericardial effusion and myocardial infarction. On the other hand, deep vein thrombosis and stroke were the most frequent for non-cardiac vascular involvement.

Conclusions

Cardiovascular disease is an important cause of hospitalization in Peruvian human immunodeficiency virus patients, with differences between immunosuppression stages. Further studies analyzing associated factors are warranted.

CD4(+) T Cells Modified by the Endoribonuclease MazF Are Safe and Can Persist in SHIV-infected Rhesus Macaques

MazF, an endoribonuclease encoded by Escherichia coli, specifically cleaves the ACA (adenine–cytosine–adenine) sequence of single-stranded RNAs. Conditional expression of MazF under the control of the HIV-1 LTR promoter rendered CD4⁺ T cells resistant to HIV-1 replication without affecting cell growth. To investigate the safety, persistence and efficacy of MazF-modified CD4⁺ T cells in a nonhuman primate model in vivo, rhesus macaques were infected with a pathogenic simian/human immunodeficiency virus (SHIV) and transplanted with autologous MazF-modified CD4⁺ T cells. MazF-modified CD4⁺ T cells were clearly detected throughout the experimental period of more than 6 months. The CD4⁺ T cell count values increased in all four rhesus macaques. Moreover, the transplantation of the MazF-modified CD4⁺ T cells was not immunogenic, and did not elicit cellular or humoral immune responses. These data suggest that the autologous transplantation of MazF-modified CD4⁺ T cells in the presence of SHIV is effective, safe and not immunogenic, indicating that this is an attractive strategy for HIV-1 gene therapy.

Evaluation of right ventricular function by Doppler tissue imaging of the tricuspid annulus in patients with acquired immune deficiency syndrome

Chronic heart disease contributes to the mortality of patients with AIDS. Although studies of left ventricular function in patients with acquired immune deficiency syndrome (AIDS) have been conducted, studies of right ventricular function are rare. The present study aimed to characterize the tricuspid annulus movement and evaluate the right ventricular function of patients with AIDS by tissue Doppler imaging. Tissue Doppler echocardiography was performed on 106 patients with AIDS and 64 controls. Tricuspid annulus movements were detected from the apical four-chamber view and the apical right heart two-chamber view. The peak diastolic early period velocity (Ve), peak diastolic later period velocity (Va) and peak systolic velocity (Vs) were measured at the anterior, posterior and lateral walls and also at the interventricular septum. Mean values were calculated, as well as the Tei index of the lateral site. Compared with the values in the control group, the Vs and Va of the AIDS group decreased at all sites with the exception of the lateral wall, whereas the Ve decreased at all sites of the tricuspid annulus (P<0.05). The Tei index was higher in the AIDS group than in the control (P<0.05). The results obtained in the present study show that the function of the right ventricle decreases in patients with AIDS, which is indicative of susceptibility to right ventricular dysfunction.

Dendritic cell dysregulation during HIV-1 infection

Dendritic cells (DCs) are a diverse subset of innate immune cells that are key regulators of the host response to human immunodeficiency virus-1 (HIV-1) infection. HIV-1 directly and indirectly modulates DC function to hinder the formation of effective antiviral immunity and fuel immune activation. This review focuses upon the differential dysregulation of myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) at various stages of HIV-1 infection providing insights into pathogenesis. HIV-1 evades innate immune sensing by mDCs resulting in suboptimal maturation, lending to poor generation of antiviral adaptive responses and contributing to T-regulatory cell (Treg) development. Dependent upon the stage of HIV-1 infection, mDC function is altered in response to Toll-like receptor ligands, which further hinders adaptive immunity and limits feasibility of therapeutic vaccine strategies. pDC interactions with HIV-1 are pleotropic, modulating immune responses on an axis between immunostimulatory and immunosuppressive. pDCs promote immune activation through an altered phenotype of persistent type I interferon secretion and weak antigen presentation capacity. Conversely, HIV-1 stimulates secretion of indolemine 2,3 dioxygenase (IDO) by pDCs resulting in Treg induction. An improved understanding of the roles and underlying mechanisms of DC dysfunction will be valuable to the development of therapeutics to enhance HIV-specific adaptive responses and to dampen immune activation.

Colorectal cancer screening in human immunodeficiency virus population: Are they at average risk?

AIM: To evaluate if human immunodeficiency virus (HIV) population is getting adequate screening for colon cancer in the highly active anti-retroviral treatment (HAART) era with improved longevity, and the prevalence of polyps and adenomas in this population, when compared with the general population.

METHODS: We conducted retrospective chart review of average-risk HIV population for colon cancer attending our infectious disease clinic. Individuals who underwent diagnostic colonoscopy were excluded. We extracted various demographic, HIV disease-specific and colonoscopy data including histo-pathological reports in the last 10 years. Total population was divided into a study group, who underwent screening colonoscopy and a control group who did not. We analyzed data using standard statistical methods and software.

RESULTS: We found that 25% of average-risk HIV-infected population was screened for colon cancer using colonoscopy. There was no difference in gender and ethnic distribution between the groups. We found wider distribution of age (50-84 years with mean 56 years) in the control group when compared to (50-73 years with mean 58 years) the study group. However, there were 89% of subjects with well-controlled HIV disease measured by HIV RNA copies of < 75 in the study group when compared with 70% in the control group (P < 0.0001). We noticed polyp detection rate of 55% and adenoma detection rate of 32% in HIV population.

CONCLUSION: It is unclear whether HIV or HAART medications play a role in increased prevalence of adenomas. We suggest that when estimating the risk for colonic neoplasms, HIV population should be considered as a high-risk group and screened accordingly.

Novel cell and gene therapies for HIV

Highly active antiretroviral therapy dramatically improves survival in HIV-infected patients. However, persistence of HIV in reservoirs has necessitated lifelong treatment that can be complicated by cumulative toxicities, incomplete immune restoration, and the emergence of drug-resistant escape mutants. Cell and gene therapies offer the promise of preventing progressive HIV infection by interfering with HIV replication in the absence of chronic antiviral therapy. Individuals homozygous for a deletion in the CCR5 gene (CCR5Δ32) are largely resistant to infection from R5-topic HIV-1 strains, which are most commonly transmitted. A recent report that an HIV-infected patient with relapsed acute myelogenous leukemia was effectively cured from HIV infection after transplantation of hematopoietic stem/progenitor cells (HSC) from a CCR5Δ32 homozygous donor has generated renewed interest in developing treatment strategies that target viral reservoirs and generate HIV resistance in a patient's own cells. Although the development of cell-based and gene transfer therapies has been slow, progress in a number of areas is evident. Advances in the fields of gene-targeting strategies, T-cell-based approaches, and HSCs have been encouraging, and a series of ongoing and planned trials to establish proof of concept for strategies that could lead to successful cell and gene therapies for HIV are under way. The eventual goal of these studies is to eliminate latent viral reservoirs and the need for lifelong antiretroviral therapy.

Tesamorelin: a review of its use in the management of HIV-associated lipodystrophy

Tesamorelin (Egrifta™) is a synthetic analogue of human growth hormone-releasing hormone (also known as growth hormone-releasing factor) that stimulates the synthesis and release of endogenous growth hormone. It is the first and, so far, only treatment indicated for the reduction of excess abdominal fat in patients with HIV-associated lipodystrophy. This article reviews the pharmacological properties, clinical efficacy and tolerability of tesamorelin in patients with HIV-associated central fat accumulation. Subcutaneous tesamorelin was effective in reducing visceral adipose tissue (VAT), but did not affect subcutaneous adipose tissue to a clinically significant extent in two 26-week, well designed, clinical trials in patients with HIV-associated central fat accumulation. This reduction in VAT was maintained in the longer term in patients who continued to receive tesamorelin until week 52 in the extension phases of the two trials. However, discontinuation of therapy during this period resulted in the reaccumulation of VAT. Tesamorelin therapy was also associated with significant improvements in other body composition measures (e.g. trunk fat and waist circumference) and improvements were generally seen in some body image parameters (e.g. belly image distress). Tesamorelin was generally well tolerated, with treatment-emergent serious adverse events occurring in <4% of patients during 26 weeks of therapy. Most of these events were injection-site reactions or events known to be associated with growth hormone therapy (e.g. arthralgia, headache and peripheral oedema). Although long-term clinical experience is needed to further assess the benefits and risks of therapy, current evidence suggests that tesamorelin may be useful for reducing visceral adiposity in patients with HIV-associated lipodystrophy, thereby potentially improving self image.

Plasmacytoid dendritic cells in HIV infection

Plasmacytoid dendritic cells (pDCs) are innate immune cells that are specialized to produce interferon-alpha (IFNα) and participate in activating adaptive immune responses. Although IFNα inhibits HIV-1 (HIV) replication in vitro, pDCs may act as inflammatory and immunosuppressive dendritic cells (DCs) rather than classical antigen-presenting cells during chronic HIV infection in vivo, contributing more to HIV pathogenesis than to protection. Improved understanding of HIV-pDC interactions may yield potential new avenues of discovery to prevent HIV transmission, to blunt chronic immune activation and exhaustion, and to enhance beneficial adaptive immune responses. In this chapter we discuss pDC biology, including pDC development from progenitors, trafficking and localization of pDCs in the body, and signaling pathways involved in pDC activation. We focus on the role of pDCs in HIV transmission, chronic disease progression and immune activation, and immunosuppression through regulatory T cell development. Lastly, we discuss potential future directions for the field which are needed to strengthen our current understanding of the role of pDCs in HIV transmission and pathogenesis.

Adverse host factors exacerbate occult HIV-associated nephropathy

In the present study, we hypothesized that HIV-1-induced occult HIV-associated nephropathy (HIVAN) would become apparent in the presence of adverse host factors. To test our hypothesis, Vpr mice (which display doxycycline-dependent Vpr expression in podocytes) with two, three, and four copies of the angiotensinogen (Agt) gene (Vpr-Agt-2, Vpr-Agt-3, and Vpr-Agt-4) were administered doxycycline for 3 weeks (to develop clinically occult HIVAN) followed by doxycycline-free water during the next 3 weeks. Subsequently, renal biomarkers were measured, and kidneys were harvested for renal histology. Vpr-Agt-2 developed neither proteinuria nor elevated blood pressure, and displayed minimal glomerular and tubular lesions only, without any microcyst formation. Vpr-Agt-3 showed mild glomerular and tubular lesions and microcyst formation, whereas Vpr-Agt-4 showed moderate proteinuria, hypertension, glomerular sclerosis, tubular dilation, microcysts, and expression of epithelial mesenchymal transition markers. Vpr-Agt-4 not only displayed enhanced renal tissue expression of Agt, renin, and angiotensin-converting enzyme, but also had higher renal tissue concentrations of angiotensin II. Moreover, renal cells in Vpr-Agt-4 showed enhanced expression of transforming growth factor-β, connective tissue growth factor, and vascular endothelial growth factor. These findings indicate that adverse host factors, such as the activation of the renin-angiotensin system, promote the progression of occult HIVAN to apparent HIVAN.

Impairment of the programmed cell death-1 pathway increases atherosclerotic lesion development and inflammation

OBJECTIVE

Programmed cell death-1 (PD-1) is a member of the CD28 superfamily that delivers negative signals on interaction with its 2 ligands, PD-L1 and PD-L2. We studied the contribution of the PD-1 pathway to regulation of T cells that promote atherosclerotic lesion formation and inflammation.

METHODS AND RESULTS

We show that compared with Ldlr-/- control mice, Pd1-/-Ldlr-/- mice developed larger lesions with more abundant CD4+ and CD8+ T cells and macrophages, accompanied by higher levels of serum tumor necrosis factor-α. Iliac lymph node T cells from Pd1-/-Ldlr-/- mice proliferated more to αCD3 or oxidized low-density lipoprotein stimulation compared with controls. CD8+ T cells from Pd1-/-Ldlr-/- mice displayed more cytotoxic activity compared with controls in vivo and in vitro. Administration of a blocking anti-PD-1 antibody increased lesional inflammation in hypercholesterolemic Ldlr-/- mice with more lesional T cells and more activated T cells in paraaortic lymph nodes. The changes in lesional T-cell content when PD-1 was absent or blocked were also observed in bone marrow chimeric Ldlr-/- mice lacking PD-L1 and PD-L2 on hematopoietic cells.

CONCLUSIONS

PD-1 has an important role in downregulating proatherogenic T-cell responses, and blockade of this molecule for treatment of viral infections or cancer may increase risk of cardiovascular complications.