Cephalosporin-resistant Pneumococci and Sickle Cell Disease

Increasingly resistant bacteria in sickle cell disease patients indicate need to evaluate extendedspectrum cephalosporin therapy

High Levels of DEK Autoantibodies in Sera of Patients With Polyarticular Juvenile Idiopathic Arthritis and With Early Disease Flares Following Cessation of Antiâ Tumor Necrosis Factor Therapy

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142962/1/art40404_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142962/2/art40404-sup-0001-Supinfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142962/3/art40404.pd

T-Lymphocytes Enable Osteoblast Maturation via IL-17F during the Early Phase of Fracture Repair

While it is well known that the presence of lymphocytes and cytokines are important for fracture healing, the exact role of the various cytokines expressed by cells of the immune system on osteoblast biology remains unclear. To study the role of inflammatory cytokines in fracture repair, we studied tibial bone healing in wild-type and Rag1−/− mice. Histological analysis, µCT stereology, biomechanical testing, calcein staining and quantitative RNA gene expression studies were performed on healing tibial fractures. These data provide support for Rag1−/− mice as a model of impaired fracture healing compared to wild-type. Moreover, the pro-inflammatory cytokine, IL-17F, was found to be a key mediator in the cellular response of the immune system in osteogenesis. In vitro studies showed that IL-17F alone stimulated osteoblast maturation. We propose a model in which the Th17 subset of T-lymphocytes produces IL-17F to stimulate bone healing. This is a pivotal link in advancing our current understanding of the molecular and cellular basis of fracture healing, which in turn may aid in optimizing fracture management and in the treatment of impaired bone healing

IL-17F promotes osteoblast maturation.

<p>(<b>A</b>) Treatment of MC3T3-E1 pre-osteoblast cell line cultures directly with pro-inflammatory cytokine IL-17F showed increased bone marker gene expression of Col1, Col2, BSP and osteocalcin, whereas, anti-inflammatory cytokine TGFβ treatment inhibited osteoblast maturation and showed significant decreases in expression of the entire panel of bone markers analyzed. (<b>B</b>) Left: Treatment of <i>Rag1^−/−</i> mice primary mesenchymal stromal cell cultures directly with pro-inflammatory cytokine IL-17F showed increased bone marker gene expression of Col1, Col2, and Runx2. Right: In contrast, treatment with anti-inflammatory cytokine TGFβ inhibited WT mice primary mesenchymal stromal cell maturation and showed significant decreases in expression of all the bone markers analyzed. (*p<0.05 and **p<0.01).</p

Proposed mechanistic scheme of T-cell mediated osteoblast differentiation and maturation.

<p>Upstream IL-6 increase early post fracture promotes naïve CD4+ T-cells to Th17 cells stimulating pre-osteoblast cell differentiation via IL-17F. Concomitantly, the Treg pathway is suppressed, decreasing TGFβ and IL-10 and inhibiting pre-osteoblast differentiation. The effect of IL-6 also has a direct role in the later stages of osteoblast differentiation in fracture healing.</p

Osteogenesis is reduced in <i>Rag1</i>

<p><i>⁻</i>^{<b><i>/</i></b><i>−</i>}<b>mice during fracture repair.</b> (<b>A</b>) <i>In vitro</i> cultures of primary mesenchymal stromal cells differentiated to osteoblast colony-forming units (CFU) showed lower gene expression levels of bone markers Col1, Col2 and BSP and osteocalcin in <i>Rag1^−/−</i> mice compared to WT. *p<0.05, **p<0.01 (n = 10). (<b>B</b>) Alizarin red staining of osteoblast CFU showed significant decrease in mineralization at 20 days of culture in <i>Rag1^−/−</i> compared to WT. CFU-osteoblast was quantified by direct counting of all stained nodules positive to Alizarin Red using light microscopy. (<b>C</b>) Digital fluorescent microscopy images of calcein green administered mice 2 and 9 days prior to harvest at 21 and 28 days post fracture exhibited a smaller distance measured between mineralization fronts and hence, less bone formation in <i>Rag1^−/−</i> compared to WT mice (p<0.05). Unfractured limbs showed no significant differences in bone formation.</p

Cytokine expression during the early phase of fracture repair.

<p>(<b>A</b>) WT and <i>Rag1^−/−</i> mice serums drawn 2 days post-fracture show elevated IL-6 and G-CSF levels compared to unfractured baseline mice. However, WT mice were found to have twice the increase in cytokine levels of IL-6 and G-CSF compared to <i>Rag1^−/−</i> mice during this early phase of fracture healing (p<0.05). (<b>B</b>) Fracture callus RNA expression analysis of cytokine levels at a similar early time point post fracture, shows a greater than 2 fold up-regulation of pro-inflammatory cytokines IL-6, IL-17F and IL-23 in WT mice compared to <i>Rag1^−/−</i> and baseline mice (p<0.05). Conversely, expression of anti-inflammatory cytokine IL-10 is up-regulated in <i>Rag1^−/−</i> and TGFβ is down-regulated in WT mice. (<b>C</b>) Immunohistochemistry analysis during the early phase of fracture healing at 3 days post fracture confirmed IL-17F positive staining (black arrows) in WT mice similar to the distribution of CD3 staining shown previously with no positive IL-17F staining in <i>Rag1^−/−</i> mice (200X).</p

Repurposing Existing Medications for Coronavirus Disease 2019: Protocol for a Rapid and Living Systematic Review

Background: Coronavirus Disease 2019 (COVID-19) has no known specific treatments. However, there might be in vitro and early clinical data as well as evidence from Severe Acute Respiratory Syndrome and Middle Eastern Respiratory Syndrome that could inform clinicians and researchers. This systematic review aims to create priorities for future research of drugs repurposed for COVID-19. Methods: This systematic review will include in vitro, animal, and clinical studies evaluating the efficacy of a list of 34 specific compounds and four groups of drugs identified in a previous scoping review. Studies will be identified both from traditional literature databases and pre-print servers. Outcomes assessed will include time to clinical improvement, time to viral clearance, mortality, length of hospital stay, and proportions transferred to the intensive care unit and intubated, respectively. We will use the GRADE methodology to assess the quality of the evidence. Discussion: The challenge posed by COVID-19 requires not just a rapid review of drugs that can be repurposed but also a sustained effort to integrate new evidence into a living systematic review