P38 MAP Kinase Inhibitor Prevents Diastolic Dysfunction in Rats Following HIV gp120 Injection In vivo

C-C chemokine receptor 5 signaling contributes to cardiac remodeling and dysfunction under pressure overload

Aortic stenosis (AS) leads to chronic pressure overload, cardiac remodeling and eventually heart failure. Chemokines and their receptors have been implicated in pressure overload‑induced cardiac remodeling and dysfunction. In the present study, the role of C‑C chemokine receptor 5 (CCR5) in pressure overload‑induced cardiac remodeling and dysfunction was investigated in mice subjected to transverse aortic constriction (TAC). Cardiac levels of CCR5 and C‑C motif chemokine ligands (CCLs)3, 4 and 5 were determined by western blotting and reverse transcription‑quantitative PCR, respectively. Cardiac functional parameters were evaluated by echocardiographic and hemodynamic measurements. Myocardial fibrosis was assessed by Masson's trichrome staining and α‑smooth muscle actin immunostaining. Myocardial hypertrophy and inflammatory cell infiltration were evaluated by hematoxylin and eosin staining. Angiotensin II (Ang II)‑induced hypertrophy of H9c2 cardiomyocytes was assessed by F‑actin immunostaining. ERK1/2 and P38 phosphorylation was examined by western blotting. TAC mice exhibited higher myocardial CCL3, CCL4, CCL5 and CCR5 levels compared with sham mice. Compared with sham mice, TAC mice also exhibited impaired cardiac function along with myocardial hypertrophy, fibrosis and inflammatory cell infiltration. TAC‑induced cardiac remodeling and dysfunction were effectively ameliorated by administration of anti‑CCR5 but not by IgG control antibody. Mechanistically, increased ERK1/2 and P38 phosphorylation was detected in TAC hearts and Ang II‑stimulated H9c2 cardiomyocytes. Treatment with anti‑CCR5 antibody decreased ERK1/2 and P38 phosphorylation and attenuated Ang II‑induced H9c2 cell hypertrophy. CCR5 inhibition protected against pressure overload‑induced cardiac abnormality. The findings of the present study indicate that ERK1/2 and P38 signaling pathways may be involved in the cardioprotective effects of CCR5 inhibition.

R5 HIV-1 gp120 Activates p38 MAPK to Induce Rat Cardiomyocyte Injury by the CCR5 Coreceptor

BACKGROUND

Effective antiretroviral therapy extends the survival of patients with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome, but these patients remain at higher risk for heart diseases compared with the general population. Previous studies have suggested that HIV-1 glycoprotein 120 (gp120) may be associated with heart disease. However, the underlying mechanisms by which HIV-1 gp120-mediated myocardial injury occurs remain unknown.

OBJECTIVE

The current study aimed to uncover the mechanism of C-C chemokine receptor 5 (CCR5) coreceptor (R5) HIV-1 gp120-induced myocardial injury.

METHODS

Morphology analysis, determination of the percentage of cell apoptosis, as well as lactate dehydrogenase (LDH) and creatine kinase (CK) assays were used to analyze whether R5 HIV-1 gp120 induced myocardial cell injury. We analyzed the phosphorylation of p38 mitogen-activated protein kinase (MAPK) with the CCR5 antagonist D-Ala-peptide T-amide (DAPTA) and NMDA receptor antagonist MK801, detected LDH and CK assays with p38 MAPK antagonist SB203580 (SB), and detected the percentage of cell apoptosis and death with DAPTA to investigate the mechanism of R5 HIV-1 gp120-induced myocardial cell injury.

RESULTS

R5 HIV-1 gp120 damaged myocardial cells and induced p38 MAPK phosphorylation. SB blocked R5 HIV-1 gp120-induced myocardial cell injury. DAPTA blocked R5 HIV-1 gp120-mediated p38 MAPK phosphorylation, while MK801 did not. DAPTA inhibited R5 HIV-1 gp120-induced myocardial cell injury.

CONCLUSION

Our data indicate that R5 HIV-1 gp120 activated p38 MAPK to trigger myocardial cell injury by the CCR5 coreceptor.

Cardiomyopathy and Heart Failure in Patients With HIV Infection

With the advent and widespread use of antiretroviral therapy (ART), the epidemiology of cardiomyopathy and heart failure (HF) associated with HIV infection is changing. Near-normal life expectancy in contemporary HIV-infected populations has been associated with prolonged exposure to increased cardiometabolic burden and chronic immune activation and systemic inflammation. Therefore, the pre-ART phenotype of HIV-associated cardiomyopathy with overt left ventricular systolic dysfunction and poor prognosis has been replaced over time by cardiomyopathy with a more insidious course, more frequent ischemic background, and highly prevalent left ventricular diastolic dysfunction. Patients with HIV are more prone to development of coronary artery disease and development of HF after myocardial infarction. The role of ongoing immune activation and systemic inflammation, despite highly active ART (HAART), appears to be central in this process. The role of HAART toxicity is controversial, as HAART itself appears to be protective for the development of HF, but recent data suggest that protease inhibitors might adversely affect the course of HIV-associated HF. Because of these unique features, the optimal therapeutic approach for HIV-associated cardiomyopathy remains unknown. The current therapeutic approaches are an extrapolation from noninfected populations. Importantly, the significance of the highly prevalent diastolic abnormalities among HIV-infected patients is not known. Therefore, further research is needed to identify its prognostic implications. Considering the prevalence of structural and functional cardiac abnormalities in HIV-infected persons and the lack of evidence on how to best screen and treat these patients, systematic research on this topic is a public health priority.

Murine models of diastolic dysfunction and heart failure with preserved ejection fraction

Left ventricular diastolic dysfunction leads to heart failure with preserved ejection fraction, an increasingly prevalent condition largely driven by modern day lifestyle risk factors. As heart failure with preserved ejection fraction accounts for almost one-half of all patients with heart failure, appropriate nonhuman animal models are required to improve our understanding of the pathophysiology of this syndrome and to provide a platform for preclinical investigation of potential therapies. Hypertension, obesity, and diabetes are major risk factors for diastolic dysfunction and heart failure with preserved ejection fraction. This review focuses on murine models reflecting this disease continuum driven by the aforementioned common risk factors. We describe various models of diastolic dysfunction and highlight models of heart failure with preserved ejection fraction reported in the literature. Strengths and weaknesses of the different models are discussed to provide an aid to translational scientists when selecting an appropriate model. We also bring attention to the fact that heart failure with preserved ejection fraction is difficult to diagnose in animal models and that, therefore, there is a paucity of well described animal models of this increasingly important condition.

CCR5 inhibition prevents cardiac dysfunction in the SIV/macaque model of HIV

Background

Diastolic dysfunction is a highly prevalent cardiac abnormality in asymptomatic as well as ART‐treated human immunodeficiency virus (HIV) patients. Although the mechanisms underlying depressed cardiac function remain obscure, diastolic dysfunction in SIV‐infected rhesus macaques is highly correlated with myocardial viral load. As cardiomyocytes are not productively infected, damage may be an indirect process attributable to a combination of pro‐inflammatory mediators and viral proteins.

Methods and Results

Given the diverse roles of CCR5 in mediating recruitment of leukocytes to inflammatory sites and serving as a receptor for HIV entry into cells, we investigated the role of CCR5 in the SIV/macaque model of diastolic dysfunction. We found that in SIV‐infected macaques, CCR5 inhibition dramatically impacted myocardial viral load measured by qRT‐PCR and prevented diastolic dysfunction measured by echocardiography. Complementary in vitro experiments using fluorescence microscopy showed that CCR5 ligands impaired contractile function of isolated cardiomyocytes, thus identifying CCR5 signaling as a novel mediator of impaired cardiac mechanical function.

Conclusions

Together, these findings incriminate SIV/HIV gp120‐CCR5 as well as chemokine‐CCR5 interactions in HIV‐associated cardiac dysfunction. These findings also have important implications for the treatment of HIV‐infected individuals: in addition to antiviral properties and reduced chemokine‐mediated recruitment and activation of inflammatory cells, CCR5 inhibition may provide a cardioprotective benefit by preventing cardiomyocyte CCR5 signaling.

Relationships among HIV infection, metabolic risk factors, and left ventricular structure and function

Our objective was to determine if the presence of metabolic complications (MC) conveyed an additional risk for left ventricular (LV) dysfunction in people with HIV. HIV⁺ and HIV⁻ men and women were categorized into four groups: (1) HIV⁺ with MC (43±7 years, n=64), (2) HIV⁺ without MC (42±7 years, n=59), (3) HIV⁻ with MC (44±8 years, n=37), or (4) HIV⁻ controls without MC (42±8 years, n=41). All participants underwent two-dimensional (2-D), Doppler, and tissue Doppler echocardiography. Overall, the prevalence of systolic dysfunction (15 vs. 4%, p=0.02) and LV hypertrophy (9 vs. 1%, p=0.03) was greater in HIV⁺ than in HIV⁻ participants. Participants with MC had a greater prevalence of LV hypertrophy (10% vs. 1%). Early mitral annular velocity during diastole was significantly (p<0.005) lower in groups with MC (HIV⁺/MC⁺: 11.6±2.3, HIV⁻/MC⁺: 12.0±2.3 vs. HIV⁺/MC⁻: 12.4±2.3, HIV⁻/MC⁻: 13.1±2.4 cm/s) and tended to be lower in groups with HIV (p=0.10). However, there was no interaction effect of HIV and MC for any systolic or diastolic variable. Regardless of HIV status, participants with MC had reduced LV diastolic function. Although both the presence of MC and HIV infection were associated with lower diastolic function, there was no additive negative effect of HIV on diastolic function beyond the effect of MC. Also, HIV was independently associated with lower systolic function. Clinical monitoring of LV function in individuals with metabolic risk factors, regardless of HIV status, is warranted.

Cardiac disease in adolescents with delayed diagnosis of vertically acquired HIV infection

BACKGROUND

At least one-third of human immunodeficiency virus (HIV)-infected infants survive to adolescence even without antiretroviral therapy (ART), but are at high risk of complications including cardiac disease. We investigated the characteristics of cardiac disease among adolescents with HIV infection diagnosed in late childhood who were receiving ambulatory HIV care in Harare, Zimbabwe.

METHODS

Consecutive adolescents with vertically acquired HIV attending 2 HIV outpatient treatment clinics were studied. Assessment included clinical history and examination, and 2-dimensional, M-mode, pulsed- and continuous-wave Doppler echocardiography.

RESULTS

Of 110 participants (47% male; median age, 15 years; interquartile range, 12-17 years), 78 (71%) were taking ART. Exertional dyspnea, chest pain, palpitations, and ankle swelling were reported by 47 (43%), 43 (39%), 10 (9%), and 7 (6%), respectively. The New York Heart Association score was ≥ 2 in 41 participants (37%). Echocardiography showed that 74 participants (67%) had left ventricular (LV; septal and/or free wall) hypertrophy and 27 (24%) had evidence of impaired LV relaxation or restrictive LV physiology. The estimated pulmonary artery systolic pressure (ePASP) was >30 mm Hg in 4 participants (3.6%); of these 2 also had right ventricular (RV) dilatation. Another 32 participants (29%), without elevated ePASP, had isolated RV dilatation.

CONCLUSIONS

A significant burden of cardiac disease was seen among adolescents with vertically acquired HIV infection. More than half were asymptomatic yet had significant echocardiographic abnormalities. These findings highlight the need to screen this population in order to better define the geography, natural history, etiopathogenic mechanisms, and management (including the timing and choice of optimal therapeutic ART and cardiac drug interventions) to prevent development and/or progression of HIV-associated cardiac disease.