ABO gene editing for the conversion of blood type A to universal type O in Rhnull donor-derived human-induced pluripotent stem cells.

The limited availability of red cells with extremely rare blood group phenotypes is one of the global challenges in transfusion medicine that has prompted the search for alternative self-renewable pluripotent cell sources for the in vitro generation of red cells with rare blood group types. One such phenotype is the Rhnull , which lacks all the Rh antigens on the red cell membrane and represents one of the rarest blood types in the world with only a few active blood donors available worldwide. Rhnull red cells are critical for the transfusion of immunized patients carrying the same phenotype, besides its utility in the diagnosis of Rh alloimmunization when a high-prevalence Rh specificity is suspected in a patient or a pregnant woman. In both scenarios, the potential use of human-induced pluripotent stem cell (hiPSC)-derived Rhnull red cells is also dependent on ABO compatibility. Here, we present a CRISPR/Cas9-mediated ABO gene edition strategy for the conversion of blood type A to universal type O, which we have applied to an Rhnull donor-derived hiPSC line, originally carrying blood group A. This work provides a paradigmatic example of an approach potentially applicable to other hiPSC lines derived from rare blood donors not carrying blood type O.

Circadian rhythms in thrombosis and atherothrombotic events.

Biological circadian rhythms in living organisms are regulated by molecular clocks. Several of these clocks are present in blood vessels, peripheral tissues, and immune cells. There is strong evidence linking dysregulation of circadian rhythms to the development of cardiovascular disease. Dysregulation of circadian rhythms is believed to activate inflammatory processes at specific times of day, leading to an increased risk of thrombosis and atherosclerosis progression. Research into circadian clock genes and molecular networks has the potential to identify therapeutic targets to reduce cardiovascular risk. In this review, we summarize the evidence linking circadian rhythms to thrombosis and atherothrombotic events and discuss potential therapeutic implications.

Selective Segmental Pulmonary Angiography: Anatomical, Technical and Safety Aspects of a Must-Learn Technique in Times of Balloon Pulmonary Angioplasty for Chronic Thromboembolic Pulmonary Hypertension.

With the advent of balloon pulmonary angioplasty (BPA) for non-surgical chronic thromboembolic pulmonary hypertension (CTEPH) patients, there is renewed interest in the pulmonary angiography technique. This technique is still the standard imaging modality to confirm CTEPH, which, in addition, helps to determine the most appropriate treatment. Furthermore, learning this technique fulfills two main purposes: to identify BPA candidates and to provide the operator with the catheter handling needed to perform BPA. Operators interested in performing BPA must learn not only the pulmonary arteries' anatomy, but also which are the best angiographic projections and the most suitable catheters to canalize and display each segmental branch. Unfortunately, this information is scarce in the literature. With this goal, learning the diagnostic pulmonary angiography technique can be a first step on the way to perform BPA. Although there are descriptions on how to perform a pulmonary angiography with balloon-tipped catheters and the digital subtraction technique, this technique does not provide operators with the catheter knowledge and manual skill needed to cannulate each segmental branch. In contrast, learning the conventional selective segmental pulmonary angiography (SSPA) technique provides the operator with this knowledge and skills. In this review, based on the experience of the authors, we describe the pulmonary arteries' anatomy and detail the practical aspects of the SSPA procedure, with the aim of providing operators with the anatomical and technical knowledge needed to perform BPA. We also summarize the contemporary complications of SSPA in CTEPH patients at a reference center.

Clinical relevance of adding intravascular ultrasound to coronary angiography for the diagnosis of extrinsic left main coronary artery compression by a pulmonary artery aneurysm in pulmonary hypertension.

OBJECTIVES: We sought to assess the clinical value of adding intravascular ultrasound (IVUS) evaluation to coronary angiography (CA) to guide extrinsic left main coronary artery (LMCA) compression diagnosis and treatment in pulmonary hypertension (PH). BACKGROUND: LMCA compression due to a pulmonary artery aneurysm (PAA) is a severe complication of PH. Although guidelines encourage the use of IVUS for LMCA disease evaluation, it has hardly been used in this scenario. METHODS: We analyzed morbimortality of type 1 and 4 PH patients with clinically suspected LMCA compression by a PAA between 2010 and 2018 in a reference unit. LMCA compression was prospectively assessed with CA ± IVUS. Angiographic-LMCA compression was considered conclusive when LMCA stenosis>50% was present in four predetermined projections; inconclusive, when LMCA stenosis>50% was present in <4 projections and negative if no stenosis>50% was present. Patients with conclusive and inconclusive CA underwent IVUS. IVUS-LMCA compression was defined as systolic minimum lumen area < 6 mm2 . RESULTS: LMCA compression was suspected in 23/796 patients (3%). CA was conclusive for compression in 7(30.5%), inconclusive in 9(39%), and negative in 7(30.5%). IVUS confirmed LMCA compression in 6/7(86%) patients with conclusive CA and in 2/9(22%) with inconclusive CA. Patients fulfilling IVUS criteria for LMCA compression underwent stent implantation. At 20 months follow-up a composite end-point of death, stent restenosis/thrombosis, or lung transplant was reported in three patients (13%). CONCLUSIONS: CA can misdiagnose LMCA extrinsic compression. IVUS discriminates better whether significant compression by a PAA exists or not, avoiding unnecessary LMCA stenting. Patients treated following this strategy show a low rate of major clinical events at 20 months follow-up.

Influence of long-standing pulmonary arterial hypertension and its severity on pulmonary artery aneurysm development.

Pulmonary artery aneurysm (PAA) is a common finding in patients with long-term pulmonary arterial hypertension (PAH). The influence of PAH severity in the development of PAA remains unclear. We sought to determine whether PAA development is related to PAH severity and whether treatment optimization based on risk profile estimation is effective to stop pulmonary artery (PA) enlargement. This is a retrospective study of 125 PAH patients who underwent an imaging test (computed tomography or magnetic resonance) combined with a right heart catheterization within a six-month period. A multivariate analysis was performed to identify independent risk factors for PAA. Patients who underwent an additional imaging-test and RHC during follow-up were analyzed to evaluate changes on PA dimensions. PAA was diagnosed in 42 (34%) patients. PAA was more frequent in patients with congenital heart disease and toxic oil syndrome. PAH time-course showed to be an independent risk factor for PAA (HR 1.051, 95% CI 1.013-1.091, p = 0.008) whereas PAH severity did not. Twenty-six patients underwent a follow-up imaging-test and catheterization. After treatment optimization, a non-significant reduction of mean PA pressure was observed (58.5 mmHg [43.5-70.8] vs. 55.5 mmHg [47.5-66.3], p = 0.115) and a higher proportion of patients achieved a low-risk profile (19% vs. 35%, p = 0.157). However, the PA diameter significantly increased (40.4 ± 10.1 mm vs. 42.1 ± 9.6 mm; p = 0.003). PAA is a common condition in long-standing PAH but its development is not necessarily related to PAH severity. Despite stabilization after treatment optimization, a progressive PA dilatation was observed.