Pulmonary hypertension in HIV infection: a prospective echocardiographic study

HIV and Drug Use: A Tale of Synergy in Pulmonary Vascular Disease Development

Over the past two decades, with the advent and adoption of highly active anti-retroviral therapy, HIV-1 infection, a once fatal and acute illness, has transformed into a chronic disease with people living with HIV (PWH) experiencing increased rates of cardio-pulmonary vascular diseases including life-threatening pulmonary hypertension. Moreover, the chronic consequences of tobacco, alcohol, and drug use are increasingly seen in older PWH. Drug use, specifically, can have pathologic effects on the cardiovascular health of these individuals. The "double hit" of drug use and HIV may increase the risk of HIV-associated pulmonary arterial hypertension (HIV-PAH) and potentiate right heart failure in this population. This article explores the epidemiology and pathophysiology of PAH associated with HIV and recreational drug use and describes the proposed mechanisms by which HIV and drug use, together, can cause pulmonary vascular remodeling and cardiopulmonary hemodynamic compromise. In addition to detailing the proposed cellular and signaling pathways involved in the development of PAH, this article proposes areas ripe for future research, including the influence of gut dysbiosis and cellular senescence on the pathobiology of HIV-PAH. © 2023 American Physiological Society. Compr Physiol 13:4659-4683, 2023.

Assessment of subclinical cardiac dysfunction by speckle-tracking echocardiography among people living with human immunodeficiency virus

Background

People living with HIV (PLWH) have an increased risk of developing cardiovascular diseases (CVD). As speckle-tracking echocardiography (STE) has been used to detect subclinical myocardial abnormalities, this study aims to detect early cardiac impairment among Asian PLWH using STE and to investigate the associated risk factors.

Methods

We consecutively recruited asymptomatic PLWH without previous CVD from a medical center of Taiwan, and their cardiac function was evaluated by conventional echocardiogram and STE. Enrolled PLWH were classified as antiretroviral therapy (ART)-experienced and ART-naive, and multivariable regressions were used to assess the association between myocardial strain and risk factors including traditional CVD and HIV-associated factors.

Results

A total of 181 PLWH (mean age: 36.4 ± 11.4 years, 173 males) were recruited and conventional echocardiogram parameters were within normal ranges. Decreased myocardial strain across the myocardium was found, with a mean left ventricular (LV) global longitudinal strain of -18.7 ± 2.9%. The LV strain in the ART-experienced group (-19.0 ± 2.9%) was significantly better than the ART-naive group (-17.9 ± 2.8%), despite a younger age and lesser CVD risk factors in the ART-naive group. Hypertension [B = 1.92, 95% confidence interval (95% CI) 0.19-3.62, p = 0.029] and ART-naive with both low and high viral loads (VL) (B = 1.09, 95% CI 0.03-2.16, p = 0.047; and B = 2.00, 95% CI, 0.22-3.79, p = 0.029) were significantly associated with reduced myocardial strain.

Conclusion

This is the first and largest cohort using STE to investigate myocardial strain in Asian PLWH. Our results suggest that hypertension and detectable VL are associated with impaired myocardial strain. Thus, timely ART administration with VL suppression and hypertension control are crucial in preventing CVD when making the management parallel with the improved life expectancy of PLWH on ART.

Long-Term Follow-up of Human Immunodeficiency Virus-Associated Pulmonary Hypertension: Clinical Features and Survival Outcomes of the Pan Africa Pulmonary Hypertension Cohort (PAPUCO)

Background

Data characterizing risk factors and long-term outcome studies on human immunodeficiency virus (HIV)-associated pulmonary hypertension (PH) in Africa are lacking.

Methods

The Pan African Pulmonary Hypertension Cohort, a multinational registry of 254 consecutive patients diagnosed with PH (97% of African descent) from 9 centers in 4 African countries was implemented. We compared baseline characteristics and 3-year survival of an HIV-infected cohort newly diagnosed with PH (PH/HIV+) to an HIV-uninfected cohort with PH (PH/HIV-).

Results

One hundred thirty-four participants with PH completed follow up (47 PH/HIV+ and 87 PH/HIV-; age median, 36 versus 44 years; P = .0004). Cardiovascular risk factors and comorbidities were similar except for previous tuberculosis (62% versus 18%, P < .0001). Six-minute walk distance (6MWD) <300 meters was common in PH/HIV- (P = .0030), but PH/HIV+ had higher heart (P = .0160) and respiratory (P = .0374) rates. Thirty-six percent of PH/HIV+ and 15% of PH/HIV- presented with pulmonary arterial hypertension (PAH) (P = .0084), whereas 36% of PH/HIV+ and 72% of PH/HIV- exhibited PH due to left heart disease (PHLHD) (P = .0009). Pulmonary hypertension due to lung diseases and hypoxia (PHLD) was frequent in PH/HIV+ (36% versus 15%) but did not reach statistical significance. Human immunodeficiency virus-associated PAH tended to have a poorer survival rate compared with PHLHD/PHLD in HIV-infected patients.

Conclusions

The PH/HIV + patients were younger and commonly had previous tuberculosis compared to PH/HIV- patients. Despite a better 6MWD at presentation, they had more signs and symptoms of early onset heart failure and a worse survival rate. Early echocardiography assessment should be performed in HIV-infected patients with history of tuberculosis who present with signs and symptoms of heart failure or posttuberculosis lung disease.

Management and prognosis of HIV-associated pulmonary arterial hypertension: 20 Years of evidence from the REHAP registry

BACKGROUND

Pulmonary arterial hypertension (PAH) is an independent predictor of death in patients with human immunodeficiency virus (HIV) infection. HIV is the leading cause of PAH (HIV-PAH) worldwide.

AIMS

We described the characteristics, treatment patterns, and prognosis of a cohort of HIV-PAH patients and compared them with those of an equivalent cohort of patients with idiopathic/familial PAH (IPAH/FPAH).

METHODS

We retrospectively analysed and compared the demographic, clinical, and treatment data from patients with HIV-PAH and those with IPAH/FPAH in the Spanish PAH registry (REHAP) from 1998 to 2018. The HIV-PAH overall survival (OS) rate up to 5 years was compared to the age- and sex-matched IPAH/FPAH population. Changes in treatment patterns in patients with HIV-PAH after 2010 and their effects on OS were also analysed.

RESULTS

Compared to those with IPAH/FPAH (n = 739), patients with HIV-PAH (n = 132) were younger, mainly men, and had a better functional status. The clinical presentation, haemodynamics, and respiratory function were similar between the groups. Parenteral drug use was the most common mode of HIV transmission. Approximately 11% of patients with HIV-PAH did not receive PAH-targeted therapy. The age- and sex-adjusted 5-year OS rate from diagnosis was 74.0% for patients with HIV-PAH and 68.7% for those with IPAH (p < 0.159). During/after 2010, 23% of patients with IPAH/FPAH received upfront dual oral combination, while oral monotherapy remained the main first-line treatment in patients with HIV-PAH. The overall OS rate remained stable.

CONCLUSIONS

Patients with HIV-PAH were predominantly young men. The short-term prognosis is similar to that of age- and sex-matched patients with IPAH/FPAH, despite a better functional status. Oral monotherapy remains the preferred first-line treatment in the current cohorts.

HIV, Combination Antiretroviral Therapy, and Vascular Diseases in Men and Women

Thanks to the advent of combination antiretroviral therapy (cART), people living with human immunodeficiency virus (HIV) (PLWH) experienced a marked increase in life expectancy but are now at higher risk for cardiovascular disease (CVD), the current leading cause of death in PLWH on cART. Although HIV preponderantly affects men over women, manifestations of HIV-related CVD differ by sex with women experiencing greater risks than men. Despite extensive investigation, the etiopathology of CVD, notably the respective contribution of viral infection and cART, remain ill-defined. However, both viral infection and cART have been reported to contribute to endothelial dysfunction, the precursor and major cause of atherosclerosis-associated CVD, through mechanisms involving endothelial cell activation, inflammation, and oxidative stress, all leading to reduced nitric oxide bioavailability. Therefore, preserving endothelial function in PLWH on cART should be a main target to reduce CVD morbidity and mortality, notably in females.

Impact of human immunodeficiency virus on pulmonary vascular disease

With the advent of anti-retroviral therapy, non-AIDS-related comorbidities have increased in people living with HIV. Among these comorbidities, pulmonary hypertension (PH) is one of the most common causes of morbidity and mortality. Although chronic HIV-1 infection is independently associated with the development of pulmonary arterial hypertension, PH in people living with HIV may also be the outcome of various co-morbidities commonly observed in these individuals including chronic obstructive pulmonary disease, left heart disease and co-infections. In addition, the association of these co-morbidities and other risk factors, such as illicit drug use, can exacerbate the development of pulmonary vascular disease. This review will focus on these complex interactions contributing to PH development and exacerbation in HIV patients. We also examine the interactions of HIV proteins, including Nef, Tat, and gp120 in the pulmonary vasculature and how these proteins alter the endothelial and smooth muscle function by transforming them into susceptible PH phenotype. The review also discusses the available infectious and non-infectious animal models to study HIV-associated PAH, highlighting the advantages and disadvantages of each model, along with their ability to mimic the clinical manifestations of HIV-PAH.

Association between HIV and incident pulmonary hypertension in US Veterans: a retrospective cohort study

Background

Pulmonary hypertension incidence based on echocardiographic estimates of pulmonary artery systolic pressure in people living with HIV remains unstudied. We aimed to determine whether people living with HIV have higher incidence and risk of pulmonary hypertension than uninfected individuals.

Methods

In this retrospective cohort study, we evaluated data from participants in the Veterans Aging Cohort Study (VACS) referred for echocardiography with baseline pulmonary artery systolic pressure measures of 35 mm Hg or less. Incident pulmonary hypertension was defined as pulmonary artery systolic pressure higher than 35 mm Hg on subsequent echocardiogram. We used Poisson regression to estimate incidence rates (IRs) of pulmonary hypertension by HIV status. We then estimated hazard ratios (HRs) by HIV status using Cox proportional hazards regression. We further categorised veterans with HIV by CD4 count or HIV viral load to assess the association between pulmonary hypertension risk and HIV severity. Models included age, sex, race or ethnicity, prevalent heart failure, chronic obstructive pulmonary disease, hypertension, smoking status, diabetes, body-mass index, estimated glomerular filtration rate, hepatitis C virus infection, liver cirrhosis, and drug use as covariates.

Findings

Of 21 314 VACS participants with at least one measured PASP on or after April 1, 2003, 13 028 VACS participants were included in the analytic sample (4174 [32%] with HIV and 8854 [68%] without HIV). Median age was 58 years and 12 657 (97%) were male. Median follow-up time was 3·1 years (IQR 0·9-6·8) spanning from April 1, 2003, to Sept 30, 2017. Unadjusted IRs per 1000 person-years were higher in veterans with HIV (IR 28·6 [95% CI 26·1-31·3]) than in veterans without HIV (IR 23·4 [21·9-24·9]; p=0·0004). The risk of incident pulmonary hypertension was higher among veterans with HIV than among veterans without HIV (unadjusted HR 1·25 [95% CI 1·12-1·40], p<0·0001). After multivariable adjustment, this association was slightly attenuated but remained significant (HR 1·18 [1·05-1·34], p=0·0062). Veterans with HIV who had a CD4 count lower than 200 cells per μL or of 200-499 cells per μL had a higher risk of pulmonary hypertension than did veterans without HIV (HR 1·94 [1·49-2·54], p<0·0001, for those with <200 cell μL and HR 1·29 [1·08-1·53], p=0·0048, for those with 200-499 cells per μL). Similarly, veterans with HIV who had HIV viral loads of 500 copies per mL or more had a higher risk of pulmonary hypertension than did veterans without HIV (HR 1·88 [1·46-2·42], p<0·0001).

Interpretation

HIV is associated with pulmonary hypertension incidence, adjusting for risk factors. Low CD4 cell count and high HIV viral load contribute to increased pulmonary hypertension risk among veterans with HIV. Thus, as with other cardiopulmonary diseases, suppression of HIV should be prioritised to lessen the burden of pulmonary hypertension in people living with HIV.

Funding

National Heart, Lung, and Blood Institute (National Institutes of Health, USA); National Institute on Alcohol Abuse and Alcoholism (National Institutes of Health, USA).

Assessment of Pulmonary Arterial Hemodynamic and Vascular Changes by Pulmonary Pulse Transit Time in Patients with Human Immunodeficiency Virus Infection

INTRODUCTION

Pulmonary arterial hypertension and human immunodeficiency virus (HIV) infection is a well-known association. Pulmonary pulse transit time (pPTT) is a recent echocardiographic marker that might be used for evaluation of pulmonary arterial stiffness (PAS) in patients with HIV infection. We aimed to investigate whether pPTT elevated in patients with HIV infection compared to healthy controls and its association with echocardiographic indices of right ventricular functions.

MATERIALS AND METHODS

Fifty HIV (+) patients from infectious disease outpatient clinics and fifty age- and sex-matched HIV (-) healthy volunteers were enrolled in this study. pPTT was measured from pulmonary vein flow velocity as the time interval between the R-wave in the electrocardiography and corresponding peak late systolic was then calculated as the mean from two separate pw-Doppler measurements.

RESULTS

pPTT, tricuspid annular peak systolic excursion (TAPSE) and right ventricle fractional area change (FAC) were significantly lower in patients with HIV than control patients (177.1 ± 34.9 vs. 215.7 ± 35.7 msn, P < 0.001; 2.33 ± 0.28 vs. 2.19 ± 0.22, P = 0.039; 45 [4.25] vs. 41.1 [4.0], P = 0.032, respectively). pPTT was positively correlated with FAC, TAPSE and cluster of differentiation 4 count (r = 0.210; P = 0.036, r = 0.256; P = 0.041, r = 0.304; P = 0.044, respectively).

CONCLUSION

Our study showed that pPTT, TAPSE, and right ventricle FAC levels were lower in patients with HIV infection. pPTT is an important predictor in patients with HIV expected to develop pulmonary vascular pathology.

Prevalence and risk factors of pulmonary hypertension among adult patients with HIV infection in Ethiopia

Globally, non-communicable diseases are increasing in people living with HIV. Pulmonary hypertension is a rare non-communicable disease in people living with HIV with a reported prevalence of <1%. However, data on pulmonary hypertension in people living with HIV from Africa are scarce and are non-existent from Ethiopia. This study aimed to examine the prevalence and severity of echocardiographic pulmonary hypertension and risk factors associated with pulmonary hypertension in people living with HIV in Ethiopia. A total of 315 consecutive adult people living with HIV followed at the Tikur Anbessa Specialized Hospital HIV Referral Clinic were enrolled from June 2018 to February 2019. Those with established pulmonary hypertension of known causes were excluded. A structured questionnaire was used to collect data on demographics, respiratory symptoms, physical findings, physician-diagnosed lung disease, and possible risk factors. Pulmonary hypertension was defined by a tricuspid regurgitant velocity of ≥2.9 m/sec on transthoracic echocardiography. A tricuspid regurgitant velocity ≥3.5, which translates into a pulmonary arterial pressure/right ventricular systolic pressure of ≥50 mmHg, was considered moderate-to-severe pulmonary hypertension. The mean age of the participants was 44.5 ± 9.8 years and 229 (72.7%) were females. Pulmonary hypertension was diagnosed in 44 (14.0%) of participants, of whom 9 (20.5%) had moderate-to-severe disease. In those with pulmonary hypertension, 17 (38.6%) were symptomatic: exertional dyspnea, cough, and leg swelling were seen in 12 (27.3%), 9 (20.5%), and 4 (9.1%), respectively. There was no significant difference in those with pulmonary hypertension compared to those without the disease by gender, cigarette smoking, previous history of pulmonary tuberculosis treatment, physician-diagnosed chronic obstructive pulmonary disease or bronchial asthma, duration of anti-retroviral therapy therapy or anti-retroviral regimen type. Pulmonary hypertension looks to be a frequent complication in people living with HIV in Ethiopia and is often associated with significant cardiopulmonary symptoms. Further studies using right heart catheterization are needed to better determine the etiology and prevalence of pulmonary hypertension in people living with HIV in Ethiopia compared to other countries.

HIV- and HCV-specific markers and echocardiographic pulmonary artery systolic pressure among United States veterans

Hepatitis C virus (HCV) may increase pulmonary hypertension (PH) risk among people living with HIV (PLWH). Prior studies on this topic have been relatively small and examined selected populations. We determine whether HIV/HCV coinfection is associated with higher pulmonary artery systolic pressure (PASP) and prevalent echocardiographic PH. We performed a cross-sectional analysis of 6032 (16% HIV/HCV coinfected) Veterans Aging Cohort Study participants enrolled 4/1/2003-9/30/2012 with echocardiographic PASP measures. We performed multiple linear and logistic regression analyses to determine whether HIV/HCV mono- or co-infection were associated with PASP and PH compared to uninfected individuals. Individuals with HIV/HCV coinfection displayed a higher PASP than uninfected individuals ([Formula: see text]=1.10, 95% CI 0.01, 2.20) but there was no association between HIV/HCV coinfection and prevalent PH. Subset analyses examined HIV and HCV disease severity markers separately and jointly. Among PLWH, HCV coinfection ([Formula: see text]=1.47, 95% CI 0.26, 2.67) and CD4 + cell count ([Formula: see text]= - 0.68, 95% CI - 1.10, - 0.27), but not HIV viral load nor ART regimen, were associated with PASP. Among people with HCV, neither HIV coinfection nor HCV biomarkers were associated with PASP. Among US veterans referred for echocardiography, HIV/HCV coinfection was not associated with a clinically significant elevation in pulmonary pressure. Lower absolute CD4 + T-cell count was inversely associated with PASP which warrants further investigation in prospective studies.

Pulmonary Hypertension in HIV

Human immunodeficiency virus-associated pulmonary arterial hypertension (HIV-PAH) is important to recognize given its association with significant morbidity and mortality. With the introduction of antiretroviral therapy, the focus of disease management has largely shifted from treating immunodeficiency-related opportunistic infections to managing chronic cardiopulmonary complications. Symptoms are nonspecific, and a high index of clinical suspicion is needed to avoid significant delay in the diagnosis of HIV-PAH. Although several viral proteins have been implicated in the pathogenesis of HIV-PAH, the exact mechanism remains uncertain. Further studies are needed to elucidate precise pathogenic mechanisms, early diagnostic tools, and novel therapeutic targets to improve prognosis of this severe complication.

HIV and Cardiovascular Disease: Update on Clinical Events, Special Populations, and Novel Biomarkers

PURPOSE OF REVIEW

The objective of this review is to provide an update on the link between HIV infection and cardiovascular disease (CVD). We will focus our review mainly on literature describing clinical CVD events and understudied topics of importance.

RECENT FINDINGS

Heart failure, peripheral artery disease, and stroke are CVD modalities deserving more attention in the context of HIV infection in the highly active antiretroviral therapy era. Incidence data on clinical CVD from HIV populations in low- and middle-income countries are limited. Multisubstance use is common in HIV, but understudied as a moderator or mediator of the association between HIV and CVD. CVD risk assessment in HIV remains challenging, but new research into novel biomarkers may provide further insights. There is also a need for inclusion of non-biologic factors in our attempts to understand, quantify, and predict CVD risk among PLWHA. Significant attention has been paid to generating and testing hypotheses to understand the mechanisms of myocardial infarction in HIV. Similar attention is deserving for heart failure, PAD, stroke, and cardiovascular disease risk in resource-limited settings and among substance users with HIV.

Pulmonary hypertension in the global population of adolescents and adults living with HIV: a systematic review and meta-analysis

A systematic review and meta-analysis was conducted to estimate the prevalence of PH in adolescents and adults living with HIV at the global level. PubMed, EMBASE, Web of Science, and Global Index Medicus were searched to identify articles published until November 4, 2018. PH had to be investigated with transthoracic echography or right heart catheterization (RHC). A random-effects model was used to pool individual studies. Overall, 25 studies with 42,642 participants from 17 countries were included. One study reported the prevalence of PH among HIV-infected adults based on RHC: 0.5% (95% confidence interval (CI): 0.3–0.6). The global prevalence of PH based on echography was 8.3% (95% CI: 4.6–12.8; 22 studies) among HIV-infected adults. In subgroup analysis, there was no difference between regions, human development indicator, and HIV burden in countries. Among HIV-infected adolescents, the prevalence of PH based on echography was 14.0% (95% CI: 2.2–33.1; 2 studies). This study suggests a high prevalence of PH in the global adolescent and adult population infected with HIV. As such, PH in this vulnerable population should be prioritized by HIV healthcare providers, policy makers and stakeholders for improved detection, overall proper management and efficient control.

Echocardiographic assessment of pulmonary arterial stiffness in human immunodeficiency virus-infected patients

BACKGROUND

Pulmonary hypertension (PH) is one of the complications of human immunodeficiency virus (HIV) infection. Despite the emergence of effective therapies, pulmonary arterial hypertension is commonly seen, especially at advanced stages. At the time of diagnosis, a majority of patients are at New York Heart Association-Functional Class III or IV. Many of the current screening modalities are dependent on detecting a rise in pulmonary arterial pressure (PAP). However, high capacitance of the pulmonary circulation implies that early microcirculation loss is not accompanied by a change in resting PAP. Therefore, we aimed to demonstrate early changes in pulmonary vascular disease in HIV-infected patients with a new echocardiographic parameter, called as pulmonary arterial stiffness (PAS).

METHODS AND RESULTS

Thirty-six HIV-infected patients and 36 age- and sex-matched healthy control subjects were enrolled in this study. PAS was calculated echocardiographically by using maximal frequency shift and acceleration time of the pulmonary artery flow trace. There was no significant difference in diastolic functions, right ventricular diameters, systolic PAP, inferior vena cava widths, right atrial area, and tricuspid annular plane systolic excursion values between the two groups. However, PAS was calculated as 24.3 ± 6.4 Hz/msn in HIV-infected patients and 19.3 ± 3.1 Hz/msn in healthy control group (P < 0.001). Increase in PAS was correlated with duration of HIV infection (P < 0.05).

CONCLUSION

Our results suggest that HIV infection affects pulmonary vascular bed starting early onset of disease and this can be demonstrated by an easy-to-measure echocardiographic parameter.

Diagnosis of pulmonary hypertension

A revised diagnostic algorithm provides guidelines for the diagnosis of patients with suspected pulmonary hypertension, both prior to and following referral to expert centres, and includes recommendations for expedited referral of high-risk or complicated patients and patients with confounding comorbidities. New recommendations for screening high-risk groups are given, and current diagnostic tools and emerging diagnostic technologies are reviewed.

Diagnosis of pulmonary hypertension

A revised diagnostic algorithm provides guidelines for the diagnosis of patients with suspected pulmonary hypertension, both prior to and following referral to expert centres, and includes recommendations for expedited referral of high-risk or complicated patients and patients with confounding comorbidities. New recommendations for screening high-risk groups are given, and current diagnostic tools and emerging diagnostic technologies are reviewed.

Drug abuse and HIV-related pulmonary hypertension: double hit injury

: Improved survival among HIV-1-infected individuals with the advent of antiretroviral therapy has clearly led to a greater prevalence of noninfectious complications. One of the most devastating sequelae in these individuals is the development of pulmonary arterial hypertension (PAH). Various epidemiological studies suggest worse survival of HIV-PAH patients when compared with other forms of PAH. Given that only a subset and not all HIV-infected individuals develop HIV-PAH, it is suggested that an additional second-hit of genetic or environmental trigger is needed for the development of PAH. In this context, it has been well documented that HIV patients who abuse illicit drugs such as stimulants, opioids, and the like, are more susceptible to develop PAH. In this review, we highlight the studies that support the significance of a double hit of HIV and drug abuse in the incidence of PAH and focus on the research that has been undertaken to unravel the pathobiology and vascular remodeling mechanisms underlying the deleterious synergy between HIV infection and drugs of abuse in orchestrating the development of PAH.

Notch3/VEGF-A axis is involved in TAT-mediated proliferation of pulmonary artery smooth muscle cells: Implications for HIV-associated PAH

The incidence of pulmonary arterial hypertension (PAH) is a significant co-morbidity observed in HIV (+) individuals. Pulmonary artery smooth muscle cells (PASMCs)—key components of the arterial vessel wall that regulate vessel diameter, demonstrate increased proliferation and hypertrophy in the lungs of HIV infected individuals, underscoring the role of these cells in the pathogenesis of HIV-associated PAH. While several pathways have been implicated in enhanced proliferation of PASMCs, detailed molecular mechanism(s) underlying HIV-associated PASMC proliferation still remain elusive. In the current study, we sought to investigate the effects HIV protein transactivator of transcription (TAT)-mediated proliferation on PASMCs. In agreement with earlier findings, our results also demonstrated TAT-mediated proliferation of human PASMCs. We identified activation of a novel Notch3 signaling pathway in TAT-mediated proliferation of PASMCs. Further validation of the Notch 3 pathway was demonstrated using both pharmacological (γ-secretase inhibitor, DAPT), as well as genetic approaches (Notch3 siRNA). Vascular endothelial growth factor A (VEGF-A) was identified as a novel downstream molecule that was induced following Notch activation. Findings from in vitro studies were further validated in archived simian immunodeficiency virus (SIV)-infected monkey lung tissues. There was increased activation of Notch3 signaling as well as enhanced expression of VEGF-A in the lungs of SIV-infected macaques compared with the lungs of SIV(−) controls. Taken together, we demonstrated that HIV-TAT increased the proliferation of PASMCs via the Notch3/VEGF-A axis. Targeting the Notch3/VEGF-A axis could thus be considered a potential therapeutic approach for the treatment of HIV-associated PAH.

Network of MicroRNAs Mediate Translational Repression of Bone Morphogenetic Protein Receptor-2: Involvement in HIV-Associated Pulmonary Vascular Remodeling

BACKGROUND

Earlier, we reported that the simultaneous exposure of pulmonary arterial smooth muscle cells to HIV proteins and cocaine results in the attenuation of antiproliferative bone morphogenetic protein receptor-2 (BMPR2) protein expression without any decrease in its mRNA levels. Therefore, in this study, we aimed to investigate the micro RNA-mediated posttranscriptional regulation of BMPR2 expression.

METHODS AND RESULTS

We identified a network of BMPR2 targeting micro RNAs including miR-216a to be upregulated in response to cocaine and Tat-mediated augmentation of oxidative stress and transforming growth factor-β signaling in human pulmonary arterial smooth muscle cells. By using a loss or gain of function studies, we observed that these upregulated micro RNAs are involved in the Tat- and cocaine-mediated smooth muscle hyperplasia via regulation of BMPR2 protein expression. These in vitro findings were further corroborated using rat pulmonary arterial smooth muscle cells isolated from HIV transgenic rats exposed to cocaine. More importantly, luciferase reporter and in vitro translation assays demonstrated that direct binding of novel miR-216a and miR-301a to 3'UTR of BMPR2 results in the translational repression of BMPR2 without any degradation of its mRNA.

CONCLUSIONS

We identified for the first time miR-216a as a negative modulator of BMPR2 translation and observed it to be involved in HIV protein(s) and cocaine-mediated enhanced proliferation of pulmonary smooth muscle cells.

Hyperactive TGF-β Signaling in Smooth Muscle Cells Exposed to HIV-protein(s) and Cocaine: Role in Pulmonary Vasculopathy

We earlier demonstrated synergistic increase in the proliferation of pulmonary smooth muscle cells on exposure to HIV-proteins and/or cocaine due to severe down-modulation of bone morphogenetic protein receptor (BMPR) axis: the anti-proliferative arm of TGF-β super family of receptors. Here, now we demonstrate the effect of HIV-Tat and cocaine on the proliferative TGF-β signaling cascade. We observed a significant increase in the secretion of TGF-β1 ligand along with enhanced protein expression of TGFβ Receptor (TGFβR)-1, TGFβR-2 and phosphorylated SMAD2/3 in human pulmonary arterial smooth muscle cells on treatment with cocaine and Tat. Further, we noticed an increase in the levels of p-TAK1 complexed with TGFβR-2. Concomitant to this a significant increase in the activation of TAK1-mediated, SMAD-independent downstream signaling molecules: p-MKK4 and p-JNK was observed. However, activation of MKK3/6-p38MAPK, another axis downstream of TAK1 was found to be reduced due to attenuation in the protein levels of BMPR2. Both SMAD and non-SMAD dependent TGFβR cascades were found to contribute to hyper-proliferation. Finally the increase in the levels of phosphorylated TGFβR1 and TGFβR2 on exposure to HIV-proteins and cocaine was confirmed in pulmonary smooth muscle cells from cocaine injected HIV-transgenic rats and in total lung extracts from HIV infected cocaine and/or opioid users.

Maintaining lung health with longstanding HIV

PURPOSE OF REVIEW

Human immunodeficiency virus (HIV) is now managed as a chronic disease. Non-infectious pulmonary conditions have replaced infection as the biggest threat to lung health, particularly as HIV cohorts age, but there is no consensus on how best to maintain long-term lung health. We review the epidemiology and pathogenesis of chronic obstructive pulmonary disease (COPD), pulmonary arterial hypertension (PAH), and lung cancer in HIV-seropositive individuals.

RECENT FINDINGS

Diagnoses of COPD are now up to 50% more prevalent in HIV-seropositive individuals than HIV-uninfected controls, and prospective pulmonary function studies find significant impairment in 7% to more than 50% of HIV-seropositive individuals. The prevalence of HIV-PAH is 0.2-0.5%, and lung cancer is two to three times more prevalent in HIV-seropositive individuals. Although host factors such as age and smoking have a role, HIV is an independent contributor to the pathogenesis of COPD, PAH, and lung cancer. Chronic inflammation, immune senescence, oxidative stress, and direct effects of viral proteins are all potential pathogenetic mechanisms. Despite their prevalence, non-infectious lung diseases remain underrecognized and evidence for effective screening strategies in HIV-seropositive individuals is limited.

SUMMARY

COPD, PAH, and lung cancer are a growing threat to lung health in the highly active antiretroviral therapy era necessitating early recognition.

Mechanical Ventilation Outcomes in Patients With Pulmonary Hypertension in the United States: A National Retrospective Cohort Analysis

OBJECTIVE

The outcome of patients with pulmonary arterial hypertension (PAH) who undergo mechanical ventilation is not well known.

METHODS

The Nationwide Inpatient Sample for 2006 to 2012 was used to isolate patients with a diagnosis of PAH who also underwent invasive (MV) and noninvasive (NIMV) mechanical ventilation. The primary outcome was in-hospital mortality.

RESULTS

The hospital records of 55 208 382 patients were studied, and there were 21 070 patients with PAH, of whom 1646 (7.8%) received MV and 834 (4.0%) received NIMV. Those receiving MV had higher mortality (39.1% vs 12.6%, P < .001) and longer hospital stays (11.9 days, interquartile range [IQR] 6.1-22.2 vs 6.7 days, IQR 3.4-11.9, P < .001) than those undergoing NIMV. Of the patients treated with MV, 4.4% also used home oxygen therapy and had similar overall mortality to those who did not use home oxygen (35.3% vs 39.1%, P = .46). Similarly, there was no relationship between home oxygen use and mortality in patients treated with NIMV (10.6% vs 12.6%, P = .48). Notably, more patients treated with NIMV used home oxygen than those treated with MV (14.4% vs 4.4%, P < .001).

CONCLUSION

Patients with PAH who undergo invasive mechanical ventilation have an in-hospital mortality of 39.1%. Future work may help identify the types of patients who benefit most from advanced respiratory support in a critical care setting.

Pharmacological treatment of HIV-associated pulmonary hypertension

Pulmonary arterial hypertension (PAH) is a rare but severe disease that results from chronic obstruction of small pulmonary arteries, leading to right ventricular failure and, ultimately, death. One established risk factor for the development of PAH is HIV infection. The presence of PAH is an independent risk factor for mortality in HIV-infected patients. This article will focus on HIV-associated PAH (HIV-PAH) with special considerations to the available treatments. With the approval of the soluble guanylate cyclase stimulator riociguat, a new drug class has become available in addition to the already existing prostanoids, endothelin receptor antagonists, and phosphodiesterase type 5 inhibitors. Guidelines for the treatment of idiopathic PAH and guidelines for antiretroviral therapy should be followed for the treatment of HIV-PAH.