15 research outputs found
Isolation and in vitro characterization of murine young-adult long bone skeletal progenitors
No full textSkeletal stem and progenitor cells (SSPCs) constitute a reservoir of bone-forming cells necessary for bone development, modeling and remodeling, as well as for fracture healing. Recent advances in tools to identify and isolate SSPCs have revealed that cells with multipotent properties are present not only in neonatal bone, but also in adult bone marrow and periosteum. The long bone metaphysis and endosteum have been proposed as an additional SSPC niche, although in vitro approaches to study their cellular and molecular characteristics are still limited. Here, we describe a comprehensive procedure to isolate and culture SSPCs derived from the metaphysis and endosteum of young-adult mice. Based on flow cytometry analysis of known SSPC markers, we found the presence of putative multipotent SSPCs, similar to neonatal bone tissue. In vitro, metaphyseal/endosteal SSPCs possess self-renewing capacity, and their multipotency is underscored by the ability to differentiate into the osteogenic and adipogenic lineage, while chondrogenic potential is limited. Expansion of metaphyseal/endosteal SSPCs under low oxygen conditions increases their proliferation capacity, while progenitor properties are maintained, likely reflecting their hypoxic niche in vivo. Collectively, we propose a validated isolation and culture protocol to study metaphyseal/endosteal SSPC biology in vitro
Mental health impact of COVID-19 in frontline healthcare workers in a Belgian Tertiary care hospital: a prospective longitudinal study
No full textObjectives: A prospective longitudinal single-centre study to assess the mental health impact of COVID-19 on nurses working in the frontline during the first wave of COVID-19 hospitalizations in Belgium, 2020. Patients and Methods: The study was performed between April 1(st) and 30 June 2020. Nurses who were actively and daily involved in the care of COVID-19 patients on selected intensive care units (ICU) and non-ICU wards were included. Depression, somatization, anxiety and distress scores were calculated using the Four-Dimensional Symptom Questionnaire (4DSQ). The Impact of Event Scale-Revised (IES-R) and Brief-COPE questionnaires were used to assess respectively the psychological impact and coping strategies. Participants were asked to fill in the questionnaire at the start of inclusion, 4 weeks later and 8 weeks later. Results: In total, 39/42 included nurses participated in the study. 4DSQ results showed low rates of depression, anxiety and somatization with a declining trend over time. Distress scores however were high throughout the study period. A past history of stress symptoms was significantly associated with higher distress scores at the inclusion and one month follow-up. As major psychological impact, more participants experienced 'intrusion' compared to 'avoidance' specifically among nurses working on ICU. In 10% of participants, IES-R-scores were predictive for post-traumatic stress disorder. Conclusion: Healthcare workers dealing with COVID-19 patients during the pandemic reported high and enduring distress scores and experienced a major impact on mental health, especially when employed at ICU. These results highlight the importance of psychological support and proper long-term follow-up to mitigate this impact.Messiaen, P (corresponding author), Jessa Hosp, Dept Infect Dis & Immun, Hasselt, Belgium.
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Image_1_Isolation and in vitro characterization of murine young-adult long bone skeletal progenitors.tif
No full textSkeletal stem and progenitor cells (SSPCs) constitute a reservoir of bone-forming cells necessary for bone development, modeling and remodeling, as well as for fracture healing. Recent advances in tools to identify and isolate SSPCs have revealed that cells with multipotent properties are present not only in neonatal bone, but also in adult bone marrow and periosteum. The long bone metaphysis and endosteum have been proposed as an additional SSPC niche, although in vitro approaches to study their cellular and molecular characteristics are still limited. Here, we describe a comprehensive procedure to isolate and culture SSPCs derived from the metaphysis and endosteum of young-adult mice. Based on flow cytometry analysis of known SSPC markers, we found the presence of putative multipotent SSPCs, similar to neonatal bone tissue. In vitro, metaphyseal/endosteal SSPCs possess self-renewing capacity, and their multipotency is underscored by the ability to differentiate into the osteogenic and adipogenic lineage, while chondrogenic potential is limited. Expansion of metaphyseal/endosteal SSPCs under low oxygen conditions increases their proliferation capacity, while progenitor properties are maintained, likely reflecting their hypoxic niche in vivo. Collectively, we propose a validated isolation and culture protocol to study metaphyseal/endosteal SSPC biology in vitro.</p
Image_2_Isolation and in vitro characterization of murine young-adult long bone skeletal progenitors.tif
No full textSkeletal stem and progenitor cells (SSPCs) constitute a reservoir of bone-forming cells necessary for bone development, modeling and remodeling, as well as for fracture healing. Recent advances in tools to identify and isolate SSPCs have revealed that cells with multipotent properties are present not only in neonatal bone, but also in adult bone marrow and periosteum. The long bone metaphysis and endosteum have been proposed as an additional SSPC niche, although in vitro approaches to study their cellular and molecular characteristics are still limited. Here, we describe a comprehensive procedure to isolate and culture SSPCs derived from the metaphysis and endosteum of young-adult mice. Based on flow cytometry analysis of known SSPC markers, we found the presence of putative multipotent SSPCs, similar to neonatal bone tissue. In vitro, metaphyseal/endosteal SSPCs possess self-renewing capacity, and their multipotency is underscored by the ability to differentiate into the osteogenic and adipogenic lineage, while chondrogenic potential is limited. Expansion of metaphyseal/endosteal SSPCs under low oxygen conditions increases their proliferation capacity, while progenitor properties are maintained, likely reflecting their hypoxic niche in vivo. Collectively, we propose a validated isolation and culture protocol to study metaphyseal/endosteal SSPC biology in vitro.</p
Low-dose systemic scopolamine disrupts context conditioning in rats
No full textCholinergic neurotransmission plays a key role in learning and memory. Prior research with rats indicated that a low dose of pre-training scopolamine (0.1 mg/kg), a cholinergic receptor antagonist, did not affect cued fear conditioning, but did block renewal when injected before extinguishing a conditioned tone, opening up opportunities to pharmacologically improve exposure therapy for anxiety patients. Before translating these findings to the clinic, it is important to carefully examine how scopolamine affects contextual fear memories. Here, we investigated the effects of scopolamine on encoding of contextual anxiety and its generalization in male Wistar rats. We found a profound disruption of context conditioning, suggesting that, even at a low dose, systemic scopolamine may influence contextual encoding in the hippocampus, particularly when the context is the best predictor for the presence of shocks.sponsorship: The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Research Foundation - Flanders (FWO) Postdoctoral Fellowship 1295613N and Research Grant 1504614N (to L Luyten) and KU Leuven Center for Excellence on Generalization Research Grant PF/10/005 (to T Beckers). Preparation of this manuscript was further supported by ERC Consolidator Grant 648176 (to T Beckers). (Research Foundation - Flanders (FWO)|1295613N, Research Foundation - Flanders (FWO)|1504614N, KU Leuven Center for Excellence on Generalization Research Grant|PF/10/005, ERC|648176, European Research Council (ERC)|648176)status: Publishe
Inhibition of the Oxygen Sensor PHD2 Enhances Tissue-Engineered Endochondral Bone Formation
No full textTissue engineering holds great promise for bone regenerative medicine, but clinical translation remains challenging. An important factor is the low cell survival after implantation, primarily caused by the lack of functional vasculature at the bone defect. Interestingly, bone development and repair initiate predominantly via an avascular cartilage template, indicating that chondrocytes are adapted to limited vascularization. Given these advantageous properties of chondrocytes, we questioned whether tissue-engineered cartilage intermediates implanted ectopically in mice are able to form bone, even when the volume size increases. Here, we show that endochondral ossification proceeds efficiently when implant size is limited (≤30 mm3 ), but chondrogenesis and matrix synthesis are impaired in the center of larger implants, leading to a fibrotic core. Increasing the level of angiogenic growth factors does not improve this outcome, because this strategy enhances peripheral bone formation, but disrupts the conversion of cartilage into bone in the center, resulting in a fibrotic core, even in small implants. On the other hand, activation of hypoxia signaling in cells before implantation stimulates chondrogenesis and matrix production, which culminates in enhanced bone formation throughout the entire implant. Together, our results show that induction of angiogenesis alone may lead to adverse effects during endochondral bone repair, whereas activation of hypoxia signaling represents a superior therapeutic strategy to improve endochondral bone regeneration in large tissue-engineered implants. © 2018 American Society for Bone and Mineral Research.sponsorship: The TCS SP8-MP system used for intravital imaging at the VIB-KU Leuven Centre for Cancer Biology was funded by a structural grant from the Hercules Foundation (AKUL/11/033). GC acknowledges funding support from the Fund for Scientific Research-Flanders (FWO: G.096414, G0A4216N). PJS is a fellow from the Agency for Innovation by Science and Technology in Flanders (IWT). SS is financed by a postdoctoral grant of the Research Foundation-Flanders (FWO/12H5917N). NvG is funded by BOF-KU Leuven GOA project 3M120209. This work is part of Prometheus, the KU Leuven R&D Division of Skeletal Tissue Engineering. We thank Karen Moermans, Ingrid Stockmans, and Shauni Loopmans for excellent technical assistance. The collagen type I-dsRed mouse and pJ320 plasmid were kindly provided by Sunichi Murakami. pWPXLd was a gift from Didier Trono (Addgene #12258). (Hercules Foundation|AKUL/11/033, Fund for Scientific Research-Flanders|FWO: G.096414, Fund for Scientific Research-Flanders|G0A4216N, Research Foundation-Flanders|FWO/12H5917N, BOF-KU Leuven GOA project|3M120209)status: Publishe
Adaptations in hepatic glucose metabolism after chronic social defeat stress in mice
No full textChronic stress has been shown to induce hyperglycemia in both peripheral blood and the brain, yet the detailed mechanisms of glucose metabolism under stress remain unclear. Utilizing 13C6-labeled glucose to trace metabolic pathways, our study investigated the impact of stress by chronic social defeat (CSD) on glucose metabolites in the liver and brain one week post-stress. We observed a reduction in 13C6-enrichment of glucose metabolites in the liver, contrasting with unchanged levels in the brain. Notably, hepatic glycogen levels were reduced while lactate concentrations were elevated, suggesting lactate as an alternative energy source during stress. Long-term effects were also examined, revealing normalized blood glucose levels and restored glycogen stores in the liver three weeks post-CSD, despite sustained increases in food intake. This normalization is hypothesized to result from diminished glucagon levels leading to reduced glycogen phosphorylase activity. Our findings highlight a temporal shift in glucose metabolism, with hyperglycemia and glycogen depletion in the liver early after CSD, followed by a later phase of metabolic stabilization. These results underscore the liver's critical role in adapting to CSD and provide insights into the metabolic adjustments that maintain glucose homeostasis under prolonged stress conditions
DataSheet_1_The Combination of the CDK4/6 Inhibitor, Palbociclib, With the Vitamin D3 Analog, Inecalcitol, Has Potent In Vitro and In Vivo Anticancer Effects in Hormone-Sensitive Breast Cancer, But Has a More Limited Effect in Triple-Negative Breast Cancer.docx
No full textActive vitamin D3, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], and its synthetically derived analogs possess potent anticancer properties. In breast cancer (BC) cells, 1,25(OH)2D3 blocks cell proliferation and induces apoptosis through different cell-type specific mechanisms. In this study, we evaluated if the combination of the potent vitamin D3 analog, inecalcitol, with a selective CDK4/6 inhibitor, palbociclib, enhanced the antiproliferative effects of both single compounds in hormone-sensitive (ER+) BC, for which palbociclib treatment is already approved, but also in triple-negative BC (TNBC). Inecalcitol and palbociclib combination treatment decreased cell proliferation in both ER+ (T47D-MCF7) and TNBC (BT20-HCC1143-Hs578T) cells, with a more pronounced antiproliferative effect in the former. In ER+ BC cells, the combination therapy downregulated cell cycle regulatory proteins (p)-Rb and (p)-CDK2 and blocked G1-S phase transition of the cell cycle. Combination treatment upregulated p-mTOR and p-4E-BP1 protein expression in MCF7 cells, whereas it suppressed expression of these proteins in BT20 cells. Cell survival was decreased after inecalcitol treatment either alone or combined in MCF7 cells. Interestingly, the combination therapy upregulated mitochondrial ROS and mitotracker staining in both cell lines. Furthermore, in vivo validation in a MCF7 cell line-derived xenograft mouse model decreased tumor growth and cell cycle progression after combination therapy, but not in a TNBC BT20 cell line-derived xenograft model. In conclusion, we show that addition of a potent vitamin D3 analog to selective CDK4/6 inhibitor treatment results in increased antiproliferative effects in ER+ BC both in vitro and in vivo.</p
DataSheet_2_The Combination of the CDK4/6 Inhibitor, Palbociclib, With the Vitamin D3 Analog, Inecalcitol, Has Potent In Vitro and In Vivo Anticancer Effects in Hormone-Sensitive Breast Cancer, But Has a More Limited Effect in Triple-Negative Breast Cancer.docx
No full textActive vitamin D3, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], and its synthetically derived analogs possess potent anticancer properties. In breast cancer (BC) cells, 1,25(OH)2D3 blocks cell proliferation and induces apoptosis through different cell-type specific mechanisms. In this study, we evaluated if the combination of the potent vitamin D3 analog, inecalcitol, with a selective CDK4/6 inhibitor, palbociclib, enhanced the antiproliferative effects of both single compounds in hormone-sensitive (ER+) BC, for which palbociclib treatment is already approved, but also in triple-negative BC (TNBC). Inecalcitol and palbociclib combination treatment decreased cell proliferation in both ER+ (T47D-MCF7) and TNBC (BT20-HCC1143-Hs578T) cells, with a more pronounced antiproliferative effect in the former. In ER+ BC cells, the combination therapy downregulated cell cycle regulatory proteins (p)-Rb and (p)-CDK2 and blocked G1-S phase transition of the cell cycle. Combination treatment upregulated p-mTOR and p-4E-BP1 protein expression in MCF7 cells, whereas it suppressed expression of these proteins in BT20 cells. Cell survival was decreased after inecalcitol treatment either alone or combined in MCF7 cells. Interestingly, the combination therapy upregulated mitochondrial ROS and mitotracker staining in both cell lines. Furthermore, in vivo validation in a MCF7 cell line-derived xenograft mouse model decreased tumor growth and cell cycle progression after combination therapy, but not in a TNBC BT20 cell line-derived xenograft model. In conclusion, we show that addition of a potent vitamin D3 analog to selective CDK4/6 inhibitor treatment results in increased antiproliferative effects in ER+ BC both in vitro and in vivo.</p
Imagined solidarities: Black liberal internationalism and the National Council of Negro Women from Afro-Asian to Pan-African unity, 1935-1975
No full text“Imagined Solidarities” examines Black women’s efforts to reform liberal internationalism in the mid-twentieth century. Focusing on one of the largest African American women’s organizations, the National Council of Negro Women (the Council), I show how women such as Sue Bailey Thurman, Mary McLeod Bethune, Edith Sampson, Vivian Carter Mason, Dorothy Ferebee, and Dorothy Height pursued racial and gender justice domestically and worldwide through collaboration with Asian, African, and African-descended women. Council women forged friendships and political partnerships with Vijaya Lakshmi Pandit and Rustomji Faridoonji of India, Begum Ra’ana Liaquat Ali Khan of Pakistan and with prominent African and African-descended women activists including Flora Azikiwe of Nigeria and Evelyn Amarteifio of Ghana. These collaborations had political consequences domestically and internationally. At the same time, Council women reimagined liberalism through what I call a pleasurable internationalism. I argue that their worldviews and commitments to American identity and US hegemony complicated, limited, and, at times, even thwarted these efforts. I apply Black feminist theoretical frameworks on a multi- archival source base that combines personal and organizational papers as well as published memoirs. My approach reveals how Council leaders and their allies relied on the intimate domain for their attempts to make the world anew. By studying Council leaders and their allies, I expand scholarship on twentieth-century Black internationalism that focuses primarily on Black radical and male liberal activists. In so doing, I offer an account of sustained international activities beginning before World II, continuing through the anticommunist suppression of the 1950s to the 1975 United Nations-sponsored International Women’s Year activities.Ph.D.Includes bibliographical reference
