Ex utero mouse embryogenesis from pre-gastrulation to late organogenesis.

The mammalian body plan is established shortly after the embryo implants into the maternal uterus, and our understanding of post-implantation developmental processes remains limited. Although pre- and peri-implantation mouse embryos are routinely cultured in vitro1,2, approaches for the robust culture of post-implantation embryos from egg cylinder stages until advanced organogenesis remain to be established. Here we present highly effective platforms for the ex utero culture of post-implantation mouse embryos, which enable the appropriate development of embryos from before gastrulation (embryonic day (E) 5.5) until the hindlimb formation stage (E11). Late gastrulating embryos (E7.5) are grown in three-dimensional rotating bottles, whereas extended culture from pre-gastrulation stages (E5.5 or E6.5) requires a combination of static and rotating bottle culture platforms. Histological, molecular and single-cell RNA sequencing analyses confirm that the ex utero cultured embryos recapitulate in utero development precisely. This culture system is amenable to the introduction of a variety of embryonic perturbations and micro-manipulations, the results of which can be followed ex utero for up to six days. The establishment of a system for robustly growing normal mouse embryos ex utero from pre-gastrulation to advanced organogenesis represents a valuable tool for investigating embryogenesis, as it eliminates the uterine barrier and allows researchers to mechanistically interrogate post-implantation morphogenesis and artificial embryogenesis in mammals.

The Hemodynamic Effects of Aortic Regurgitation in Patients Supported by a HeartMate 3 Left Ventricular Assist Device.

BACKGROUND: Aortic regurgitation (AR) is a common complication following left ventricular assist device (LVAD) implantation. We evaluated the hemodynamic implications of AR in patients with HeartMate 3 (HM3) LVAD at baseline and in response to speed changes. METHODS AND RESULTS: Clinically stable outpatients supported by HM3 who underwent a routine hemodynamic ramp test were retrospectively enrolled in this analysis. Patients were stratified based on the presence of at least mild AR at baseline speed. Hemodynamic and echocardiographic parameters were compared between the AR and non-AR groups. Sixty-two patients were identified. At the baseline LVAD speed, 29 patients (47%) had AR, while 33 patients (53%) did not. Patients with AR were older and supported on HM3 for a longer duration. At baseline speed, all hemodynamic parameters were similar between the groups including central venous pressure, pulmonary capillary wedge pressure, pulmonary arterial pressures, cardiac output and index, and pulmonary artery pulsatility index (p > 0.05 for all). During the subacute assessment, AR worsened in some, but not all, patients, with increases in LVAD speed. There were no significant differences in 1-year mortality or hospitalization rates between the groups, however, at 1-year, ≥ moderate AR and right ventricular failure (RVF) were detected in higher rates among the AR group compared to the non-AR group (45% vs. 0%; p < 0.01, and 75% vs. 36.8%; p = 0.02, respectively). CONCLUSIONS: In a cohort of stable outpatients supported with HM3 who underwent a routine hemodynamic ramp test, the presence of mild or greater AR did not impact the ability of HM3 LVADs to effectively unload the left ventricle during early subacute assessment. Although the presence of AR did not affect mortality and hospitalization rates, it resulted in higher rates of late hemodynamic-related events in the form of progressive AR and RVF.

Extracorporeal photopheresis and its role in heart transplant rejection: prophylaxis and treatment.

Heart transplantation is the gold standard therapeutic option for select patients with end-stage heart failure. Unfortunately, successful long-term outcomes of heart transplantation can be hindered by immune-mediated rejection of the cardiac allograft, specifically acute cellular rejection, antibody-mediated rejection, and cardiac allograft vasculopathy. Extracorporeal photopheresis is a cellular immunotherapy that involves the collection and treatment of white blood cells contained in the buffy coat with a photoactive psoralen compound, 8-methoxy psoralen, and subsequent irradiation with ultraviolet A light. This process is thought to cause DNA and RNA crosslinking, ultimately leading to cell destruction. The true mechanism of therapeutic action remains unknown. In the last three decades, extracorporeal photopheresis has shown promising results and is indicated for a variety of conditions. The American Society for Apheresis currently recommends the use of extracorporeal photopheresis for the treatment of cutaneous T-cell lymphoma, scleroderma, psoriasis, pemphigus vulgaris, atopic dermatitis, graft-versus-host disease, Crohn's disease, nephrogenic systemic fibrosis, and solid organ rejection in heart, lung, and liver transplantation. In this review, we aim to explore the proposed effects of extracorporeal photopheresis and to summarize published data on its use as a prophylactic and therapy in heart transplant rejection.

Hemodynamic Optimization by Invasive Ramp Test in Patients Supported With HeartMate 3 Left Ventricular Assist Device.

In patients supported by the HeartMate 3 left ventricular assist device (HM3 LVAD), pump speed adjustments may improve hemodynamics. We investigated the hemodynamic implications of speed adjustments in HM3 recipients undergoing hemodynamic ramp tests. Clinically stable HM3 recipients who underwent routine invasive hemodynamic ramp tests between 2015 and 2022 at our center were included. Filling pressure optimization, defined as central venous pressure (CVP) <12 mm Hg and pulmonary capillary wedge pressure (PCWP) <18 mm Hg, was assessed at baseline and final pump speeds. Patients with optimized pressures were compared to nonoptimized patients. Overall 60 HM3 recipients with a median age of 62 years (56, 71) and time from LVAD implantation of 187 days (124, 476) were included. Optimized filling pressures were found in 35 patients (58%) at baseline speed. Speed was adjusted in 84% of the nonoptimized patients. Consequently, 39 patients (65%) had optimized pressures at final speed. There were no significant differences in hemodynamic findings between baseline and final speeds ( p > 0.05 for all). Six and 12 month readmission-free rates were higher in optimized compared with nonoptimized patients ( p = 0.03 for both), predominantly due to lower cardiac readmission-free rates ( p = 0.052). In stable outpatients supported with HM3 who underwent routine ramp tests, optimized hemodynamics were achieved in only 2 of 3 of the patients. Patients with optimized pressures had lower all-cause readmission rates, primarily driven by fewer cardiac-related hospitalizations.

Sex differences in patients undergoing heart transplantation and LVAD therapy.

INTRODUCTION: Left ventricular assist device (LVAD) and heart transplantation (HT) are the two life-sustaining therapies that have revolutionized the management of end-stage heart failure (HF). Yet, significant sex differences exist with respect to their use and effects. AREAS COVERED: This review summarizes sex differences in the utilization, outcomes, and complications of LVAD and HT. Particular emphasis is placed on leading clinical trials in the field, historical and recent large registries-based analyses, as well as contemporary technological and policy changes affecting these differences. EXPERT OPINION: Women with advanced HF remain under-treated with guideline-directed medical therapy and are less likely to be referred for consideration for LVAD and HT. This remains true despite newer LVAD technology and the new heart transplant allocation system. Community outreach, education, as well as increased representation of women in clinical research may reduce inequities.

A Rare Case of Disseminated Tuberculosis and Hematological Malignancy in a Heart Transplant Recipient.

A 77-year-old man who underwent a heart transplant 7 years ago presented with multiple bloody bowel movements. Endoscopic and histologic evaluation revealed chronic active ileitis, granulomatous inflammation, multinucleated giant cells, and a rare, equivocal acid-fast bacterium in the terminal ileum. Positive sputum cultures for Mycobacterium tuberculosis and acid-fast bacilli established a diagnosis of intestinal tuberculosis, and RIPE (rifabutin, isoniazid, pyrazinamide, ethambutol) therapy was initiated. Elevated IgG levels on quantitative immunoglobulin testing and a bone marrow biopsy specimen of ≥60% plasma cells confirmed the diagnosis of multiple myeloma that later transformed into its aggressive form, plasma cell leukemia. Induction chemotherapy was initiated; however, the patient experienced retroperitoneal bleeding and pancytopenias, limiting the continuation of chemotherapy, and as a result, the patient was transitioned to palliative care.