Influence of antiretroviral therapy and cardiovascular disease on the immature platelet fraction in patients living with HIV

High-sensitivity C-reactive protein among people living with HIV on highly active antiretroviral therapy: a systemic review and meta-analysis

The pathological consequences of inflammation persist in people living with the human immunodeficiency virus (PLWH), regardless of the positive outcomes of highly active antiretroviral therapy (HAART). The current systematic review and meta-analysis aims to understand and explore the levels of high-sensitivity C-reactive protein (hs-CRP) and other cardiovascular disease (CVD)-risk factors including lipid profiles among PLWH on HAART. Major electronic databases including PubMed, Scopus, and Web of Science were searched to retrieve relevant global literature reporting on hs-CRP levels in PLWH on HAART. A total of twenty-two studies with an average participant age of 40 years were eligible for this systematic review and meta-analysis. Majority of the included studies were from Africa (n = 11), the United States (n = 6), and Europe (n = 5). Our systemic review showed that most studies reported increased levels of hs-CRP among PLWH on HAART when compared to controls (PLWH not on HAART or those without HIV), especially in studies from Africa. This was supported by a meta-analysis showing significantly elevated levels of hs-CRP in PLWH on HAART when compared to PLWH not on HAART (standardised mean difference [SMD] = 0.56; 95% CI = 0.10‑1.01, z = 2.41; p = 0.02) or those without HIV (SMD = 1.19; 95% CI = 0.76‑1.63, z = 5.35; p < 0.001). Where lipid profiles, as a major predictor for CVD risk, were also impaired in PLWH on HAART when compared to PLWH not on HAART and HIV-negative participants. In conclusion, elevated levels of hs-CRP and lipid levels are prevalent in PLWH on HAART, this may increase the risk of CVD complications, especially for those people living in Africa. However, more evidence in larger population studies is required to confirm these outcomes and unveil any possible clinical implications of HAART-induced modulation of hs-CRP levels in PLWH.

Association of Antiretroviral Therapy with Platelet Function and Systemic Inflammatory Response in People Living with HIV: A Cross-Sectional Study

People living with HIV (PLWHIV) present an increased risk of adverse cardiovascular events. We aimed to assess whether antiretroviral therapy (ART) pharmacologically enhances platelet reactivity and platelet activation intensity, and explore the potential association with underlying inflammatory status. This was a cross-sectional cohort study carried out among PLWHIV on diverse ART regimens. Platelet reactivity and activation intensity were assessed using the bedside point-of-care VerifyNow assay, in P2Y12 reaction units (PRU), measurements of monocyte-platelet complexes, and P-selectin and GPIIb/IIIa expression increase, following activation with ADP, respectively. Levels of major inflammatory markers and whole blood parameters were also evaluated. In total, 71 PLWHIV, 59 on ART and 22 healthy controls, were included in this study. PRU values were significantly elevated in PLWHIV compared to controls [Mean; 257.85 vs. 196.67, p < 0.0001], but no significant differences were noted between ART-naïve or ART-experienced PLWHIV, or between TAF/TDF and ABC based regimens, similar to systemic inflammatory response. However, within-group analysis showed that PRUs were significantly higher in ABC/PI vs ABC/INSTI or TAF/TDF + PI patients, in line with levels of IL-2. PRU values did not correlate strongly with CD4 counts, viral load, or cytokine values. P-selectin and GPIIb/IIIa expression increased following ADP activation and were significantly more prominent in PLWHIV (p < 0.005). Platelet reactivity and platelet activation intensity were shown to be increased in PLWHIV, but they did not appear to be related to ART initiation, similar to the underlying systemic inflammatory response.

Cardiovascular toxicity of contemporary antiretroviral therapy

PURPOSE OF REVIEW

HIV treatment has evolved since the introduction of antiretroviral therapy (ART) in the 1990s. Earlier treatment strategies, and the introduction of integrase inhibitors in preferred first-line ART have fundamentally changed cardiovascular side effects due to HIV infection and ART. This review provides an update on cardiovascular toxicity of contemporary ART.

RECENT FINDINGS

Cardiovascular disease (CVD) risk, including heart failure, is still increased in people living with HIV (PLWH). Exposure to older antiretrovirals, including stavudine and zidovudine, still impact on CVD risk through persistent changes in body fat distribution years after discontinuation. Protease inhibitors (PI) and efavirenz have associated metabolic disturbances and increased risk of CVD, although use is decreasing worldwide. Integrase inhibitors and CCR5 antagonists seem to have negligible immediate CVD toxicity. Weight gain on newer antiretrovirals including integrase inhibitors is a reason for concern.

SUMMARY

CVD risk should be monitored carefully in PLWH who were exposed to first generation ART, efavirenz or to PIs. Registries should capture ART use and CVD events to stay informed on actual clinical risk in the current era of rapid initiation on integrase inhibitor-based ART.

Immature Platelet Dynamics in Immune-Mediated Thrombocytopenic States

A major challenge encountered by clinicians is differentiating presentations characterized by significant thrombocytopenia due to overlapping clinical symptoms and signs in the setting of ambiguous laboratory results. Immature platelets represent the youngest platelets that can be measured in peripheral blood by current hematology analyzers. These young platelets are larger, with higher RNA content recently released from the bone marrow. Thrombocytopenic presentations caused directly or indirectly by immune responses can lead to compensatory bone marrow responses seeking to normalize the platelet count; thus obtaining absolute immature platelet counts may be informative while triaging patients. Over the last decade, their use has expanded beyond being an early biomarker of bone marrow reconstitution post-hematopoietic stem cell transplantation to being used to establish bone marrow responses to infection and thrombocytopenias due to immune etiologies. Its accessibility as part of more detailed platelet indices obtained with routine laboratories makes it a promising option to understand the bone marrow's real-time response to disease states characterized by thrombocytopenia. This review will look at the immature platelet count as a biomarker, while presenting current attempts trying to understand how it could be used in thrombocytopenias occurring secondary to a given immune etiology.

Sorting and magnetic-based isolation of reticulated platelets from peripheral blood

Reticulated Platelets (RPs) are large, RNA-rich, prothrombotic and hyperactive platelets known to be elevated in high-risk populations such as diabetics and patients with acute coronary syndrome. High levels of RPs correlate with mortality and adverse cardiovascular events in patients with coronary artery disease as well as with an insufficient antiplatelet response to thienopyridines and aspirin after percutaneous coronary interventions, making them an appealing drug target. However, processing of platelets is challenging and no specific marker for RPs exists. Until now, the gold standard laboratory-based method to study them is based on the flow cytometric measurement of their cell size and their RNA-content with the fluorescent dye Thiazole Orange (TO). Nevertheless, standardized protocols for staining and processing of RPs are missing and the existing techniques were not applied for cell sorting. We provide here a structured and reproducible method to detect, isolate and collect RPs from peripheral blood by RNA-specific staining with TO implementing several platelet inhibitors as well as magnetic labeling allowing sufficient cell recovery and deep biological investigation of these platelets.