Monocytes are involved in a wide range of physiological and pathological processes, many of which are studied in mouse models. Current protocols to isolate murine monocytes are few and result in unsatisfactory cell yield and purity. Here, we describe a novel approach to efficiently differentiate large numbers of mature inflammatory monocytes from heterogeneous bone marrow cell suspensions. Bone marrow cell suspensions were isolated by flushing femurs and tibias from Balb/c and C57Bl/6 mice, supplemented with macrophage colony–stimulating factor (M-CSF), and were cultured on ultra-low attachment surfaces to inhibit adherence-mediated maturation. Cells were harvested at indicated time points, underwent time-line analysis of the differentiation processes, and were subsequently extensively phenotyped to verify their monocytotic properties. In order to confirm downstream compatibility, we tested for typical monocyte behavior. Our protocol yielded 24 ± 6 × 106 differentiated cells per donor mouse, 10-fold higher than yields obtained using previously described peripheral blood isolation methods. Differentiated cells consisted of approximately 47% ± 12% monocytes, the rest being mature macrophages. We increased monocyte purity to 86% ± 6% by depleting adherent macrophages. Our findings indicate that bone marrow–derived monocytes (BMDMs) are an attractive tool to study, for example, the innate and adaptive immune system, atherosclerosis, and cellular migration during infection. Moreover, BMDM transplantation could be used to test novel, therapeutic in vivo approaches in mice disease models.

Abstract Background International guidelines have endorsed the use of edoxaban or rivaroxaban as an alternative to low-molecular-weight heparin (LMWH) for the treatment of acute venous thromboembolism (VTE) in cancer patients. Recently, a large randomized controlled trial of apixaban versus dalteparin in patients with cancer was completed. We performed an updated meta-analysis to assess the efficacy and safety of direct oral anticoagulants (DOACs) versus LMWH in patients with cancer-associated VTE. Methods MEDLINE, EMBASE, and CENTRAL (Cochrane Controlled Trials Registry) were systematically searched up to March 30, 2020 for randomized controlled trials comparing DOACs versus LMWH for the treatment of VTE in patients with cancer. The two coprimary outcomes were recurrent VTE and major bleeding at 6 months. Data were pooled by the Mantel–Haenszel method and compared by relative risk ratios (RRs) and 95% confidence intervals (CIs). Results Four randomized controlled studies (2,894 patients) comparing apixaban, edoxaban, or rivaroxaban with dalteparin were included in the meta-analysis. Recurrent VTE occurred in 75 of 1,446 patients (5.2%) treated with oral factor Xa inhibitors and in 119 of 1,448 patients (8.2%) treated with LMWH (RR 0.62; 95% CI 0.43–0.91; I 2, 30%). Major bleeding occurred in 62 (4.3%) and 48 (3.3%) patients receiving oral factor Xa inhibitors or LMWH, respectively (RR 1.31; 95% CI 0.83–2.08; I 2, 23%). Conclusion In patients with cancer-associated VTE, oral factor Xa inhibitors reduced the risk of recurrent VTE without a significantly higher likelihood of major bleeding at 6 months compared with LMWH.

In addition to haematoma and arteriovenous fistula, the iatrogenic pseudoaneurysm is a common complication of vascular access that is caused by a perforation in the arterial wall. Iatrogenic pseudoaneurysms can progress in size and lead to rupture and active bleeding. Over the previous few decades, therapeutic methods have evolved from surgical repair to less invasive options, such as ultrasound-guided compression therapy (UGCT) and ultrasound-guided thrombin injection (UGTI). This paper presents an overview of the diagnostic and treatment modalities used in femoral pseudoaneurysms as well as a comprehensive summary of previous studies that analysed the success and complication rates of UGCT and UGTI.

Therapeutic augmentation of collateral vessel growth (arteriogenesis) is of particular clinical interest. Because monocytes localize to areas of collateral growth and create a highly arteriogenic environment through secretion of multiple growth factors, we tested the hypothesis that monocyte "homing" can therapeutically be exploited. We have used a rabbit model of arteriogenesis to investigate the therapeutic potential of transplanted rabbit monocytes that were either ex vivo stimulated or adenovirally transduced to express a transgene encoding an arteriogenic growth factor. The monocytes were intravenously injected 24 hr or 7 days after ligation of the animal's right femoral artery. Seven days after transplantation collateral flow was determined with a doppler flow probe and collateral vessels were quantified angiographically. Whereas transplantation of allogeneic cells (same species) resulted in a strong promotion of arteriogenesis, most likely through induction of local inflammation and recruitment of recipient monocytes, transplantation of autologous cells (same animal) was not able to significantly augment collateralization. However, when autologous monocytes were used as vehicles to deliver granulocyte macrophage-colony stimulating factor as therapeutic transgene, collateralization was strongly augmented. Their localization to the site of collateral development posttransplantation was demonstrated by ex vivo transduction with beta-galactosidase. Because isolation of monocytes is clinically widely available their ex vivo engineering and transplantation represents an intriguing new strategy for therapeutic arteriogenesis.

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