Search

Exposure of young C57BL/6 (B6) mice to two courses of busulfan (BSF) injections or two rounds of sublethal total-body irradiation (TBI) induced significant damage to the function of hematopoietic stem and progenitor cells (HSPCs). Fifteen weeks after treatment, BSF- and TBI-treated mice had reduced white blood cells without significant change in red blood cells or platelets, indicating that BSF and TBI hematotoxicity was chronic, with leukocytes being the major targets. Hematopoietic damage induced by BSF or TBI persisted long term. Residual adverse effects were reflected by significantly decreased CD45R B cells and reduced recovery of total bone marrow cells, especially HSPCs carrying markers for KSL (Kit + Sca-1 + Lin - ) cells, multipotent progenitor (MPP) cells (KSLCD34 + CD135 + ), myeloid progenitor (MP) cells (Kit + Sca-1 - Lin - ), and common lymphoid progenitor (CLP) cells 62 wk posttreatment. Transplantation of bone marrow (BM) cells from BSF and TBI donors at 49 weeks after treatment into lethally irradiated hosts resulted in decreased engraftment of CD45R B cells in blood and reduced reconstitution of BM HSPCs including KSL cells, short-term hematopoietic stem cells (KSLCD34 + CD135 - ), MPP cells, and MP cell subsets. TBI donor had better reconstitution of CLP cells in recipients posttransplantation than did BSF donor, suggesting an impact of TBI and BSF on B cells at different development stages. In summary, BSF and TBI exposure produced long-lasting adverse effects on hematopoiesis with pronounced effects on mature B cells, immature ST-HSCs, and hematopoietic progenitor cells. Our results may have implications for therapy of human diseases., Competing Interests: Conflict of interest disclosure The authors do not have any conflicts of interest to declare in relation to this work., (Published by Elsevier Inc.)

The role of mammalian target of rapamycin and its suppressor sirolimus in the regulation of hematopoietic stem and progenitor cells (HSPCs) is controversial. We show here that sirolimus enhanced regeneration of HSPCs in mice exposed to sublethal total body irradiation (TBI) and other regenerative stressors. Sorted Lin - CD150 + bone marrow cells from sirolimus-treated TBI mice had increased expression of c-Kit and other hematopoietic genes. HSPCs from sirolimus-treated TBI mice were functionally competent when tested by competitive engraftment in vivo. Postradiation regeneration of HSPCs in mice treated with sirolimus was accompanied by decreased γ-H2AX levels detected by flow cytometry and increased expression of DNA repair genes by quantitative polymerase chain reaction. Reduction of cell death and DNA damage post-radiation by sirolimus was associated with enhanced clearance of cellular reactive oxygen species (ROS) in HSPCs. Increased HSPC recovery with sirolimus was also observed in mice injected with hematoxic agents, busulfan and 5-fluorouracil. In contrast, sirolimus showed no effect on HSPCs in normal mice at steady state, but stimulated HSPC expansion in mice carrying the Wv mutation at the c-Kit locus. In human to mouse xenotransplantation, sirolimus enhanced engraftment of irradiated human CD34 + cells. In summary, our results are consistent with sirolimus' acceleration of HSPC recovery in response to hematopoietic stress, associated with reduced DNA damage and ROS. Sirolimus might have clinical application for the treatment and prevention of hematopoietic injury., (©2020 The Authors. Stem Cells published by Wiley Periodicals LLC on behalf of AlphaMed Press 2020.)

Background: The Vanderbilt Institute for Clinical and Translational Research piloted the development of Project PLACENTA (PathLink Acquired gEstatioNal Tissue bAnk). This project investigated the feasibility of a fresh gestational tissue biobank, which provides tissue linked to electronic medical records for investigators interested in maternal-fetal health., Methods: We developed a pipeline for collection of placental tissue from Labor and Delivery within approximately 30 minutes of delivery. An email alert was developed, to signal delivery, with the ability to specifically flag patients with certain phenotypic traits. Once collected, 4 to 8 mm punch biopsy cores were snap frozen and subsequently used for DNA, RNA and protein extraction. Tissue was also collected for Formalin Fixed Paraffin Embedded (FFPE) histology, flow cytometry, and quality control measures., Results: Of 60 deliveries using the email notification system, 25 (42%) were sent to Pathology or assigned to other research protocols and were not available for collection, 10 (16%) were discarded prior to arrival at Labor and Delivery, and 25 (42%) were available for collection. Twenty placentas were collected and averaged 38 minutes per collection. DNA extraction yielded an average of 53 µg/µl per sample and RNA extraction yielded 679 ng/µl on average per sample. Proteomic studies showed no degradation of protein, abundant and similar quantities of protein across samples and differentiation between the amnion, decidua, and villi. Histological studies showed good quality for interpretation and occasional pathology including multifocal chronic villitis, meconium laden macrophages, and Stage 2 acute chorioamnionitis. Flow cytometry demonstrated good cell viability after isolation.

Objective: The objectives of this study were to: (a) describe teen feedback on an asthma question prompt list/video intervention designed to motivate teens to be more engaged during visits and (b) examine teen demographics associated with teen acceptance of the intervention., Methods: Two hundred and fifty-nine teens ages 11 to 17 with persistent asthma were enrolled into a randomized, controlled trial and assigned to either a standard care or an intervention group where they watched an educational video with their parents and received a prompt list to complete before visits. Teens were interviewed after visits., Results: Of the 185 teens randomized to the intervention group: 93% said teens should complete the prompt lists before visits; 95% recommended teens should watch the video before visits; teens with moderate/severe persistent asthma were significantly more likely to find the prompt list useful; non-White teens were significantly more likely to find the prompt list and video more useful., Conclusions: Teens exposed to the question prompt list/video had very positive feedback about the intervention., Practice Implications: Providers/practices should consider having teens complete question prompt lists during pre-visit wait time for use during visits and watch the video with their parents before visits., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Notch signaling is critical for osteoblastic differentiation; however, the specific contribution of individual Notch ligands is unknown. Parathyroid hormone (PTH) regulates the Notch ligand Jagged1 in osteoblastic cells. To determine if osteolineage Jagged1 contributes to bone homeostasis, selective deletion of Jagged1 in osteolineage cells was achieved through the presence of Prx1 promoter-driven Cre recombinase expression, targeting mesenchymal stem cells (MSCs) and their progeny (PJag1 mice). PJag1 mice were viable and fertile and did not exhibit any skeletal abnormalities at 2 weeks of age. At 2 months of age, however, PJag1 mice had increased trabecular bone mass compared to wild-type (WT) littermates. Dynamic histomorphometric analysis showed increased osteoblastic activity and increased mineral apposition rate. Immunohistochemical analysis showed increased numbers of osteocalcin-positive mature osteoblasts in PJag1 mice. Also increased phenotypically defined Lin - /CD45 - /CD31 - /Sca1 - /CD51 + osteoblastic cells were measured by flow cytometric analysis. Surprisingly, phenotypically defined Lin - /CD45 - /CD31 - /Sca1 + /CD51 + MSCs were unchanged in PJag1 mice as measured by flow cytometric analysis. However, functional osteoprogenitor (OP) cell frequency, measured by Von Kossa + colony formation, was decreased, suggesting that osteolineage Jagged1 contributes to maintenance of the OP pool. The trabecular bone increases were not due to osteoclastic defects, because PJag1 mice had increased bone resorption. Because PTH increases osteoblastic Jagged1, we sought to understand if osteolineage Jagged1 modulates PTH-mediated bone anabolism. Intermittent PTH treatment resulted in a significantly greater increase in BV/TV in PJag1 hind limbs compared to WT. These findings demonstrate a critical role of osteolineage Jagged1 in bone homeostasis, where Jagged1 maintains the transition of OP to maturing osteoblasts. This novel role of Jagged1 not only identifies a regulatory loop maintaining appropriate populations of osteolineage cells, but also provides a novel approach to increase trabecular bone mass, particularly in combination with PTH, through modulation of Jagged1. © 2017 American Society for Bone and Mineral Research., (© 2017 American Society for Bone and Mineral Research.)

Objectives: Our objective was to develop a series of short educational videos for teens and parents to watch before pediatric visits to motivate teens to be more actively involved during their visits., Methods: The development of the short educational videos was theoretically guided by Social Cognitive Theory. First we conducted four focus groups with teens (ages 11 to 17) with asthma, four focus groups with the teens' parents, and seven focus groups with pediatric providers from four clinics. The research team, which included two teens with asthma and their parents, analyzed the focus group transcripts for themes and then developed the initial video script. Next, a visual storyboard was reviewed by focus groups with parents and four with teens to identify areas of the script for improvement. The English videos were then produced. Focus groups with Hispanic parents and teens were then conducted for advice on how to modify the videos to make a more culturally appropriate Spanish version., Results: Based on focus group results, teen newscasters narrate six one- to two-minute videos with different themes: (a) how to get mom off your back, (b) asthma triggers, (c) staying active with asthma, (d) tracking asthma symptoms, (e) how to talk to your doctor and (f) having confidence with asthma. Each video clip has three key messages and emphasizes how teens should discuss these messages with their providers., Conclusions: Teens, parents, and providers gave us excellent insight into developing videos to increase teen involvement during medical visits.