Thrombosis in multiple myeloma: risk stratification, antithrombotic prophylaxis, and management of acute events. A consensus-based position paper from an ad hoc expert panel

The introduction of new therapeutic agents for multiple myeloma (MM), including proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies, has improved the outcomes of patients but, in parallel, has changed the frequency and epidemiology of thrombotic events. Thrombosis is now a significant cause of morbidity and mortality in MM patients, and optimal thromboprophylaxis is far from being reached. Moving from the recognition that the above issue represents an unmet clinical need, an expert panel assessed the scientific literature and composed a framework of recommendations for improving thrombosis control in patients who are candidates for active treatment for MM. The panel generated key clinical questions using the criterion of clinical relevance through a Delphi process. It explored four domains, i.e., thrombotic risk factors and risk stratification, primary thromboprophylaxis, management of acute thrombotic events, and secondary thromboprophylaxis. The recommendations issued may assist hematologists in minimizing the risk of thrombosis and guarantee adherence to treatment in patients with MM who are candidates for active treatment

Histone H1 Depletion Impairs Embryonic Stem Cell Differentiation

Pluripotent embryonic stem cells (ESCs) are known to possess a relatively open chromatin structure; yet, despite efforts to characterize the chromatin signatures of ESCs, the role of chromatin compaction in stem cell fate and function remains elusive. Linker histone H1 is important for higher-order chromatin folding and is essential for mammalian embryogenesis. To investigate the role of H1 and chromatin compaction in stem cell pluripotency and differentiation, we examine the differentiation of embryonic stem cells that are depleted of multiple H1 subtypes. H1c/H1d/H1e triple null ESCs are more resistant to spontaneous differentiation in adherent monolayer culture upon removal of leukemia inhibitory factor. Similarly, the majority of the triple-H1 null embryoid bodies (EBs) lack morphological structures representing the three germ layers and retain gene expression signatures characteristic of undifferentiated ESCs. Furthermore, upon neural differentiation of EBs, triple-H1 null cell cultures are deficient in neurite outgrowth and lack efficient activation of neural markers. Finally, we discover that triple-H1 null embryos and EBs fail to fully repress the expression of the pluripotency genes in comparison with wild-type controls and that H1 depletion impairs DNA methylation and changes of histone marks at promoter regions necessary for efficiently silencing pluripotency gene Oct4 during stem cell differentiation and embryogenesis. In summary, we demonstrate that H1 plays a critical role in pluripotent stem cell differentiation, and our results suggest that H1 and chromatin compaction may mediate pluripotent stem cell differentiation through epigenetic repression of the pluripotency genes