The distribution, phenotype, and requirement of macrophages for fracture-associated inflammation and/or early anabolic progression during endochondral callus formation were investigated. A murine ...femoral fracture model internally fixed using a flexible plate (MouseFix) was used to facilitate reproducible fracture reduction. IHC demonstrated that inflammatory macrophages (F4/80+ Mac-2+ ) were localized with initiating chondrification centers and persisted within granulation tissue at the expanding soft callus front. They were also associated with key events during soft-to-hard callus transition. Resident macrophages (F4/80+ Mac-2neg ), including osteal macrophages, predominated in the maturing hard callus. Macrophage Fas-induced apoptosis transgenic mice were used to induce macrophage depletion in vivo in the femoral fracture model. Callus formation was completely abolished when macrophage depletion was initiated at the time of surgery and was significantly reduced when depletion was delayed to coincide with initiation of early anabolic phase. Treatment initiating 5 days after fracture with the pro-macrophage cytokine colony stimulating factor-1 significantly enhanced soft callus formation. The data support that inflammatory macrophages were required for initiation of fracture repair, whereas both inflammatory and resident macrophages promoted anabolic mechanisms during endochondral callus formation. Overall, macrophages make substantive and prolonged contributions to fracture healing and can be targeted as a therapeutic approach for enhancing repair mechanisms. Thus, macrophages represent a viable target for the development of pro-anabolic fracture treatments with a potentially broad therapeutic window.
Distinct subsets of resident tissue macrophages are important in hematopoietic stem cell niche homeostasis and erythropoiesis. We used a myeloid reporter gene (Csf1r-eGFP) to dissect the persistence ...of bone marrow and splenic macrophage subsets following lethal irradiation and autologous hematopoietic stem cell transplantation in a mouse model. Multiple recipient bone marrow and splenic macrophage subsets survived after autologous hematopoietic stem cell transplantation with organ-specific persistence kinetics. Short-term persistence (5 weeks) of recipient resident macrophages in spleen paralleled the duration of extramedullary hematopoiesis. In bone marrow, radiation-resistant recipient CD169+ resident macrophages and erythroid-island macrophages self-repopulated long-term after transplantation via autonomous cell division. Posttransplant peak expansion of recipient CD169+ resident macrophage number in bone marrow aligned with the persistent engraftment of phenotypic long-term reconstituting hematopoietic stem cells within bone marrow. Selective depletion of recipient CD169+ macrophages significantly compromised the engraftment of phenotypic long-term reconstituting hematopoietic stem cells and consequently impaired hematopoietic reconstitution. Recipient bone marrow resident macrophages are essential for optimal hematopoietic stem cell transplantation outcomes and could be an important consideration in the development of pretransplant conditioning therapies and/or chemoresistance approaches.
•Recipient macrophages persist in hematopoietic tissues and self-repopulate via in situ proliferation after syngeneic transplantation.•Targeted depletion of recipient CD169+ macrophages after transplant impaired long-term bone marrow engraftment of hematopoietic stem cells.
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Mouse hematopoietic tissues contain abundant tissue-resident macrophages that support immunity, hematopoiesis, and bone homeostasis. A systematic strategy to characterize macrophage subsets in mouse ...bone marrow (BM), spleen, and lymph node unexpectedly reveals that macrophage surface marker staining emanates from membrane-bound subcellular remnants associated with unrelated cells. Intact macrophages are not present within these cell preparations. The macrophage remnant binding profile reflects interactions between macrophages and other cell types in vivo. Depletion of CD169+ macrophages in vivo eliminates F4/80+ remnant attachment. Remnant-restricted macrophage-specific membrane markers, cytoplasmic fluorescent reporters, and mRNA are all detected in non-macrophage cells including isolated stem and progenitor cells. Analysis of RNA sequencing (RNA-seq) data, including publicly available datasets, indicates that macrophage fragmentation is a general phenomenon that confounds bulk and single-cell analysis of disaggregated hematopoietic tissues. Hematopoietic tissue macrophage fragmentation undermines the accuracy of macrophage ex vivo molecular profiling and creates opportunity for misattribution of macrophage-expressed genes to non-macrophage cells.
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•Genuine macrophages are absent from hematopoietic tissue single-cell preparations•Fragmented remnants of macrophages containing cytoplasm adhere to other cells•Macrophage remnants convolute hematopoietic tissue flow cytometry analysis•Remnant-derived macrophage-RNA is misattributed to other cells in RNA-seq data
Millard et al. demonstrate intact macrophages are absent in hematopoietic tissue single-cell suspensions as they are disrupted during preparation. Macrophage remnants containing membrane and intracellular contents remain attached to other cells within the suspensions. This results in misassignment of macrophage identity and misattribution of macrophage-expressed genes.
We studied the association between objectively measured smartphone usage and objectively measured sleep quality and physical activity for seven consecutive days among Hong Kong adolescents and young ...adults aged 11–25 years (n = 357, 67% female). We installed an app that tracked the subjects’ smartphone usage and had them wear an ActiGraph GT3X accelerometer on their wrist to measure their sleep quality and physical activity level. Smartphone usage data were successfully obtained from 187 participants (52.4%). The participants on average spent 2 h 46 min per day on their smartphone. Multilevel regression showed that 1 min of daytime smartphone usage was associated with 0.07 min decrease in total sleeping time that night (p = .043, 95% confidence interval CI: −0.14, −0.003). Broken down for different usage purposes, 1 min of daytime social network usage and games and comics was associated with a 0.28 (p = .02, 95% CI: −0.52, −0.04) min and 0.18 min (p = .01, 95% CI: −0.32, −0.04) decrease in total sleeping time that night, respectively. One minute of daytime smartphone usage was associated with an increase of 4.55 steps in the number of steps (p = .001, 95% CI: 1.77, 7.34) on the next day. To conclude, time spent on a smartphone in the daytime was associated with total sleeping time that night and number of steps the next day, but was not associated with sleep efficiency, wake after sleep onset and moderate‐to‐vigorous‐intensity activity (MVPA) among Hong Kong adolescents and young adults.
Sexual dysfunction is a common problem for men with diabetes. Epigallocatechin gallate (EGCG) is known to ameliorate erectile function in aging rats. However, there has not yet been a report to ...evaluate its effects on diabetic male rat sexual behavior in the literature. In this study, we investigated the effects of EGCG on male sexual behavior in diabetic rats. Diabetic rats were induced by a single intraperitoneal injection of 65 mg/kg of streptozotocin. After streptozotocin injection for one week, animals were then orally treated with 40 mg/kg of EGCG or vehicle. Copulatory behavior and fasting blood glucose levels were recorded before treatment, as well as 7 and 14 days after treatment. Serum LH, testosterone, and PDE5a levels were measured by EIA assay after the last behavioral test. Data showed that diabetic rats who had diminished sexual functions demonstrated significantly increased latencies in mount, intromission, and ejaculation, as well as significant decreases in frequencies of intromission and ejaculation, compared to non-diabetic controls, indicating sexual function recovery. Lower blood glucose levels were also found in diabetic rats after EGCG treatment. Additionally, the lower LH and higher PDE5a levels in diabetic rats than controls were also noted. The findings declared that EGCG had a protective effect on male sexual behavior in diabetic rats.
This study evaluated the validity of self-reported smartphone usage data against objectively-measured smartphone usage data by directly tracking the activities in the participants' smartphone among ...Chinese adolescents and young adults in Hong Kong.
A total of 187 participants were recruited (mean age 19.4, 71.7% female) between 2017 and 2018. A smartphone usage tracking app was installed on all participants' smartphone for 7 consecutive days. After the 7-day monitoring period, they completed a selfadministered questionnaire on smartphone usage habits.
Although the correlation between self-reported and objectively-measured total smartphone usage time was insignificant (ρ=-0.10, p=0.18), in three out of the four usage domains were positively and significantly correlated, namely social network (ρ=0.21, p=0.005), instant messaging (ρ=0.27, p<0.001), and games (ρ=0.64, p<0.001). Participants' self-report of the total time spent on smartphones exceeded the objective data by around 760 min per week (self-reported 1,930.3 min/wk vs. objectively-measured 1,170.7 min/wk, p<0.001). Most of the over-reporting was contributed by the web browsing domain (self-reported 447.8 min/wk vs. objectively-measured 33.3 min/wk, p<0.001).
Our results showed large discrepancies between self-reported smartphone and objectively-measured smartphone usage except for self-reported usage on game apps.
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