Activation of NF-kappa B driven inflammatory programs in mesenchymal elements attenuates hematopoiesis in low-risk myelodysplastic syndromes

Activation of NF-κB signaling in mesenchymal cells is common in LR-MDS.Activation of NF-κB in mesenchymal cells leads to transcriptional overexpression of inflammatory factors including negative regulators of hematopoiesis.Activation of NF-κB attenuates HSPC numbers and function ex vivo

Characterization of Endothelial Cells Associated with Hematopoietic Niche Formation in Humans Identifies IL-33 As an Anabolic Factor

Bone marrow formation requires an orchestrated interplay between osteogenesis, angiogenesis, and hematopoiesis that is thought to be mediated by endothelial cells. The nature of the endothelial cells and the molecular mechanisms underlying these events remain unclear in humans. Here, we identify a subset of endoglin-expressing endothelial cells enriched in human bone marrow during fetal ontogeny and upon regeneration after chemotherapeutic injury. Comprehensive transcriptional characterization by massive parallel RNA sequencing of these cells reveals a phenotypic and molecular similarity to murine type H endothelium and activation of angiocrine factors implicated in hematopoiesis, osteogenesis, and angiogenesis. Interleukin-33 (IL-33) was significantly overexpressed in these endothelial cells and promoted the expansion of distinct subsets of hematopoietic precursor cells, endothelial cells, as well as osteogenic differentiation. The identification and molecular characterization of these human regeneration-associated endothelial cells is thus anticipated to instruct the discovery of angiocrine factors driving bone marrow formation and recovery after injury

Effect of clarithromycin in patients with suspected Gram-negative sepsis: results of a randomized controlled trial

A previous randomized study showed that clarithromycin decreases the risk of death due to ventilator-associated pneumonia and shortens the time until infection resolution. The efficacy of clarithromycin was tested in a larger population with sepsis. Six hundred patients with systemic inflammatory response syndrome due to acute pyelonephritis, acute intra-abdominal infections or primary Gram-negative bacteraemia were enrolled in a double-blind, randomized, multicentre trial. Clarithromycin (1 g) was administered intravenously once daily for 4 days consecutively in 302 patients; another 298 patients were treated with placebo. Mortality was the primary outcome; resolution of infection and hospitalization costs were the secondary outcomes. The groups were well matched for demographics, disease severity, microbiology and appropriateness of the administered antimicrobials. Overall 28 day mortality was 17.1 (51 deaths) in the placebo arm and 18.5 (56 deaths) in the clarithromycin arm (P0.671). Nineteen out of 26 placebo-treated patients with septic shock and multiple organ dysfunctions died (73.1) compared with 15 out of 28 clarithromycin-treated patients (53.6, P0.020). The median time until resolution of infection was 5 days in both arms. In the subgroup with severe sepsis/shock, this was 10 days in the placebo arm and 6 days in the clarithromycin arm (P0.037). The cost of hospitalization was lower after treatment with clarithromycin (P0.044). Serious adverse events were observed in 1.3 and 0.7 of placebo- and clarithromycin-treated patients, respectively (P0.502). Intravenous clarithromycin did not affect overall mortality; however, administration shortened the time to resolution of infection and decreased the hospitalization costs