HIV-Associated Cardiovascular Disease

Currently, 17 million people worldwide are receiving antiretroviral therapy (ART) for human immunodeficiency viral (HIV) infection. There has been a dramatic decline in mortality from HIV infection in the last decade due to increased availability of ART. HIV-associated cardiac failure is on the increase, with more cases of diastolic dysfunction reported in the ART era. HIV increases the risk of CVD, because of longer survival on ART, ongoing subclinical inflammation, traditional cardiovascular risk factors and the complications of chronic ART use. HIV-associated CVD encompasses a wide spectrum of heterogeneous clinical entities, which include diastolic dysfunction, asymptomatic left ventricular dysfunction, cardiomyopathy, myocarditis, heart failure, myocardial fibrosis, myocardial steatosis, pulmonary hypertension, peripheral arterial disease, cerebrovascular disease, infective endocarditis, coronary artery disease and cardiac neoplasms (e.g. Kaposi sarcoma and B-cell immunoblastic lymphoma). In this chapter, we review the complex association of HIV infection and CVD. We describe important recent developments and perspectives based on a systematic analysis of the important advances in this field published in the last decade

Predictors of diffuse myocardial fibrosis in HIV infected persons: A multiparametric cardiovascular magnetic resonance study

With the advent of effective antiretroviral therapy (ART), human immunodeficiency virus (HIV) is now a chronic disease. With increasing survival, cardiovascular disease (CVD) in people living with HIV is increasing in the ART era, with a changing epidemiology that is now largely characterised by diastolic dysfunction. Our hypothesis was that ART would be associated with regression of myocardial fibrosis in HIV. Myocardial fibrosis is associated with an unfavourable outcome in many different clinical settings. In this study, we used cardiovascular magnetic resonance (CMR) measurements of extracellular volume fraction (ECV) and tissue characterisation to assess diffuse myocardial fibrosis and determine the effect of ART use on diffuse myocardial fibrosis in HIV infected individuals on ART compared to untreated HIV infected persons. Forty-four asymptomatic individuals with no known CVD who were HIV infected were included and classified into two groups: 25 on ART for >1 year (60% male, mean age 40 ± 9 years) and 19 ART-naïve (37% male; mean age 36 ± 8 years). All patients underwent CMR on a 3T Siemens Skyra scanner. Imaging included cine, T2 weighted (STIR), native T1 and T2 mapping, late gadolinium imaging (LGE) and ECV imaging. HIV infected patients not on ART had a median time from diagnosis to entry in the study of 9 months. Treated patients had been stable on ART for over 12 months. There was no difference in left ventricular volumes, mass and function between treated and untreated HIV-infected patients. We found that, while elevated in both groups, the native T1 values were lower in the treated group compared to untreated patients. Again, while elevated in both groups, the ECV was slightly lower in the treated group, this did not reach statistical significance. There was no correlation between native T1 value or ECV with either disease duration or nadir CD4 count. There was no difference in left ventricular volumes, mass and function between treated and untreated HIV-infected patients. We found that, while elevated in both groups, the native T1 values were lower in the treated group compared to untreated patients. Again, while elevated in both groups, the ECV was slightly lower in the treated group, this did not reach statistical significance. There was no correlation between native or ECV with either disease duration or nadir CD4 count. We conclude that in patients with HIV, diffuse myocardial fibrosis provides valuable insights into the pathophysiology of HIV associated CVD and mechanism of diastolic dysfunction. Importantly, in this study, with a short lead period on ART, ART was associated with regression of diffuse myocardial fibrosis, as assessed by native T1, but not by ECV. Larger prospective studies are needed with longer follow-up to assess the role of CMR in both risk stratification and in tracking disease progression in HIV

Review of cardiovascular magnetic resonance in human immunodeficiency virus-associated cardiovascular disease

Despite ongoing advances in the treatment of patients with human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS), they remain a major global public health concern conferring an increased risk of morbidity and mortality in affected individuals. This is, in part, because of the widespread dysfunction imposed by HIV and its treatment on the cardiovascular system, including the myocardium, valvular apparatus, pericardium and coronary, pulmonary and peripheral vasculature. In recent times, cardiovascular magnetic resonance (CMR) imaging has emerged as the gold standard tool for assessment of a variety of indications, allowing comprehensive characterisation of functional, morphological, metabolic and haemodynamic sequelae of several cardiovascular pathologies. Furthermore, continued advancement in imaging techniques has yielded novel insights into the underlying pathophysiology and guides future therapeutic strategies. In this article, we review the various clinical phenotypes of HIV-associated cardiovascular disease and highlight the utility of CMR in their assessment

Variability of blue carbon storage in arid evaporitic environment of two coastal Sabkhas or mudflats

Abstract Coastal Sabkhas are mudflats found in arid coastal regions that are located within the supratidal zone when high rates of evaporation lead to high salinity. While evaporitic minerals often accumulate underneath the surface, the microbial mats are present on the surface of Sabkhas. Coastal Sabkha, an under-studied ecosystem in Qatar, has the potential to store blue carbon. In the present study, we investigated the carbon storage capacity of two Sabkhas from contrasting geological backgrounds. The spatial and temporal variabilities of the carbon stocks were examined. The results showed that both studied Sabkhas exhibit a considerable potential for soil carbon storage with carbon stocks of 109.11 ± 7.07 Mg C ha−1 and 67.77 ± 18.10 Mg C ha−1 in Dohat Faishakh and Khor al Adaid Sabkha respectively. These values fall within the reported range for carbon stocks in coastal Sabkhas in the region (51–194 Mg C ha−1). Interestingly, the carbon stocks in the sediments of the Sabkhas were higher than those in the sediments of Qatari mangroves (50.17 ± 6.27 Mg C ha−1). These finding suggest that coastal Sabkhas can serve as blue carbon ecosystems in arid environments

Preparation and Characterization of a Novel Mucoadhesive Carvedilol Nanosponge: A Promising Platform for Buccal Anti-Hypertensive Delivery

Carvedilol (CRV) is a non-selective third generation beta-blocker used to treat hypertension, congestive heart failure and angina pectoris. Oral administration of CRV showed poor bioavailability (25%), which might be ascribed to its extensive first-pass metabolism. Buccal delivery is known to boost drugs bioavailability. The aim of this study is to investigate the efficacy of bilosomes-based mucoadhesive carvedilol nanosponge for enhancing the oral bioavailability of CRV. The bilosomes were prepared, optimized and characterized for particle size, surface morphology, encapsulation efficiency and ex-vivo permeation studies. Then, the optimized formula was incorporated into a carboxymethyl cellulose/hydroxypropyl cellulose (CMC/HPC) composite mixture to obtain buccal nanosponge enriched with CRV bilosomes. The optimized bilosome formula (BLS9), showing minimum vesicle size, maximum entrapment, and highest cumulative in vitro release, exhibited a spherical shape with 217.2 nm in diameter, 87.13% entrapment efficiency, and sustained drug release for up to 24 h. In addition, ex-vivo drug permeation across sheep buccal mucosa revealed enhanced drug permeation with bilosomal formulations, compared to aqueous drug suspension. Consecutively, BLS9 was incorporated in a CMC/HPC gel and lyophilized for 24 h to obtain bilosomal nanosponge to enhance CRV buccal delivery. Morphological analysis of the prepared nanosponge revealed improved swelling with a porosity of 67.58%. The in vivo assessment of rats indicated that CRV-loaded nanosponge efficiently enhanced systolic/diastolic blood pressure, decreased elevated oxidative stress, improved lipid profile and exhibited a potent cardio-protective effect. Collectively, bilosomal nanosponge might represent a plausible nanovehicle for buccal delivery of CRV for effective management of hypertension