Abstract Stem cell-based strategies for bone regeneration, which use calcium phosphate (CaP)-based biomaterials in combination with developmentally relevant progenitor populations, have significant ...potential for clinical repair of skeletal defects. However, the exact mechanism of action and the stem cell–host-material interactions are still poorly understood. We studied if pre-conditioning of human periosteum-derived cells (hPDCs) in vitro could enhance, in combination with a CaP-based biomaterial carrier, ectopic bone formation in vivo . By culturing hPDCs in a biomimetic calcium (Ca2+ ) and phosphate (Pi ) enriched culture conditions, we observed an enhanced cell proliferation, decreased expression of mesenchymal stem cell (MSC) markers and upregulation of osteogenic genes including osterix, Runx2, osteocalcin, osteopontin, and BMP-2. However, the in vitro pre-conditioning protocols were non-predictive for in vivo ectopic bone formation. Surprisingly, culturing in the presence of Ca2+ and Pi supplements resulted in partial or complete abrogation of in vivo ectopic bone formation. Through histological, immunohistochemical and microfocus X-ray computed tomography (μCT) analysis of the explants, we found that in situ proliferation, collagen matrix deposition and the mediation of osteoclastic activity by hPDCs are associated to their ectopic bone forming capacity. These data were validated by the multivariate analysis and partial least square regression modelling confirming the non-predictability of in vitro parameters on in vivo ectopic bone formation. Our series of experiments provided further insights on the stem cell–host-material interactions that govern in vivo ectopic bone induction driven by hPDCs on CaP-based biomaterials.
The use of calcium phosphate (CaP)-based carriers in bone engineering is a promising approach to induce in vivo bone formation. However, the exact mechanism of osteoinduction by CaP is not known. ...Here, by mimicking the in vivo Ca(2+) and P(i)-enriched environment in an in vitro model, we assessed the effects of these ions on human periosteum-derived cells. We observed a significant Ca(2+) and P(i)-induced cell proliferation, which was found to be through the modulation of cell cycle progression, in a dose- and time-dependent manner. In addition, Ca(2+), P(i), and combined Ca-P upregulated osteogenic gene expression in a dose- and time-dependent manner. Encouragingly, both ions administered individually or in combination persistently and dose dependently upregulated bone morphogenetic protein-2 gene expression. This suggested a potential osteoinductive effect through an autonomous activation of the bone morphogenetic protein signaling pathway by released Ca(2+) and P(i), which may serve as an autocrine/paracrine osteoinduction loop that drives the cellularized CaP constructs toward effective bone formation in vivo. In conclusion, through an in vitro biomimetic model, we have partially probed the roles of the released Ca(2+) and P(i) on the osteoinductivity of CaP-based biomaterials.
Non-timely reporting, selective reporting, or non-reporting of clinical trial results are prevalent and serious issues. WHO mandates that summary results be available in registries within 12 months ...of study completion and published in full text within 24 months. However, only a limited number of clinical trials in infectious diseases, including those done during the COVID-19 pandemic, have their results posted on ClinicalTrials.gov. An analysis of 50 trials of eight antiviral drugs tested against COVID-19 with a completion date of at least 2 years ago revealed that only 18% had their results published in the registry, with 40% not publishing any results. Non-timely and non-reporting practices undermine patient participation and are ethically unacceptable. Strategies should include obligatory reporting of summary results within 12 months in clinical trial registries, with progress towards peer-reviewed publication within 24 months indicated. Timely publication of research papers should be encouraged through an automated flagging mechanism in clinical trial registries that draws attention to the status of results reporting, such as a green tick for trials that have reported summary results within 12 months and a red tick in case of failure to do so. We propose the inclusion of mandatory clinical trial reporting standards in the International Conference on Harmonization Good Clinical Practice guidelines, which should prohibit sponsor contract clauses that restrict reporting (referred to as gag clauses) and require timely reporting of results as part of the ethics committees' clearance process for clinical trial protocols.
Individuals with gray, blue, or green eyes have a higher chance of developing uveal melanoma (UM) than those with brown eyes. We wondered whether iris pigmentation might be related not only to ...predisposition to UM but also to its behavior; therefore, we compared the clinical, histopathologic, and genetic characteristics of UM between eyes with different colors.
We determined iris color in a large cohort of patients enucleated for UM. Clinical and histopathologic tumor characteristics, chromosome status, and survival were compared among 3 groups on the basis of iris color.
A total of 412 patients with choroidal/ciliary body UM, who had undergone primary enucleation at the Leiden University Medical Center, Leiden, The Netherlands, between 1993 and 2019, were divided into 3 groups based on iris color: gray/blue, green/hazel, and brown. The validation cohort included 934 patients with choroidal/ciliary body UM treated at Wills Eye Hospital (WEH).
Comparison of clinical, histopathologic, and genetic characteristics of UM in patients with different iris colors.
Melanoma-related survival in UM patients, divided over 3 iris color groups, in relation to the tumor’s chromosome 3 and 8q status.
Moderate and heavy tumor pigmentations were especially seen in eyes with a brown iris (P < 0.001). Survival did not differ between patients with different iris colors (P = 0.27); however, in patients with a light iris, copy number changes in chromosome 3 and 8q had a greater influence on survival than in patients with a dark iris. Likewise, chromosome 3 and chromosome 8q status affected survival more among patients with lightly pigmented tumors than in patients with heavily pigmented tumors. The WEH cohort similarly showed a greater influence of chromosome aberrations in light-eyed individuals.
Although iris color by itself did not relate to UM-related survival, chromosome 3 and 8q aberrations had a larger influence on survival in patients with a light iris than those with a brown iris. This suggests a synergistic effect of iris pigmentation and chromosome status in the regulation of oncogenic behavior of UM. Iris color should be taken into consideration when calculating a patient's risk for developing metastases.
Increased angiogenesis is associated with a higher metastasis- and mortality rate in uveal melanoma (UM). Recently, it was demonstrated that genetic events, such as 8q-gain and BAP1-loss, influence ...the level of immune infiltrate. We aimed to determine whether genetic events, and specific cytokines, relate to angiogenesis in UM. Data from UM patients who underwent enucleation between 1999 and 2008 were analysed. Microvascular density (MVD) and the presence of infiltrating immune cells were determined with immunohistochemistry (IHC) and immunofluorescence in 43 cases. Chromosome status, BAP1 IHC and mRNA expression of angiogenesis-related genes were known in 54 cases. Tumours with monosomy 3/BAP1-loss showed a higher MVD compared to tumours with disomy 3/normal BAP1 expression (
= 0.008 and
= 0.004, respectively). Within BAP1-positive lesions (
= 20), 8q-gain did not relate to MVD (
= 0.51). A high MVD was associated with an increased expression of angiopoietin 2 (ANGPT2) (
= 0.041), Von Willebrand Factor (VWF) (
= 0.010), a decreased expression of vascular endothelial growth factor B (VEGF-B) (
= 0.024), and increased numbers of tumour-infiltrating macrophages (CD68+,
= 0.017; CD68+CD163+,
= 0.031) and lymphocytes (CD4+,
= 0.027). Concluding, vascular density of UM relates to its genetic profile: Monosomy 3 and BAP1-loss are associated with an increased MVD, while an early event (gain of 8q) is not independently related to MVD, but may initiate a preparation phase towards development of vessels. Interestingly, VEGF-B expression is decreased in UM with a high MVD.
We have demonstrated previously that adult human synovial membrane-derived mesenchymal stem cells (hSM-MSCs) have myogenic potential in vitro. In the present study, we have characterized their ...myogenic differentiation in a nude mouse model of skeletal muscle regeneration and provide proof of principle of their potential use for muscle repair in the mdx mouse model of Duchenne muscular dystrophy. When implanted into regenerating nude mouse muscle, hSM-MSCs contributed to myofibers and to long term persisting functional satellite cells. No nuclear fusion hybrids were observed between donor human cells and host mouse muscle cells. Myogenic differentiation proceeded through a molecular cascade resembling embryonic muscle development. Differentiation was sensitive to environmental cues, since hSM-MSCs injected into the blood-stream engrafted in several tissues, but acquired the muscle phenotype only within skeletal muscle. When administered into dystrophic muscles of immunosuppressed mdx mice, hSM-MSCs restored sarcolemmal expression of dystrophin, reduced central nucleation, and rescued the expression of mouse mechano growth factor.
Uveal melanoma (UM) is a rare ocular malignancy which originates in the uveal tract, and often gives rise to metastases. Potential targets for immune checkpoint inhibition are lymphocyte-activation ...gene 3 (LAG3) and its ligands. We set out to analyse the distribution of these molecules in UM. The expression of mRNA was determined using an Illumina array in 64 primary UM from Leiden. The T lymphocyte fraction was determined by digital droplet PCR. In a second cohort of 15 cases from Leiden, mRNA expression was studied by Fluidigm qPCR, while a third cohort consisted of 80 UM from TCGA. In the first Leiden cohort, LAG3 expression was associated with the presence of epithelioid cells (p = 0.002), monosomy of chromosome 3 (p = 0.004), and loss of BAP1 staining (p = 0.001). In this Leiden cohort as well as in the TCGA cohort, LAG3 expression correlated positively with the expression of its ligands: LSECtin, Galectin-3, and the HLA class II molecules HLA-DR, HLA-DQ, and HLA-DP (all p < 0.001). Furthermore, ligands Galectin-3 and HLA class II were increased in monosomy 3 tumours and the expression of LAG3 correlated with the presence of an inflammatory phenotype (T cell fraction, macrophages, HLA-A and HLA-B expression: all p < 0.001). High expression levels of LAG3 (p = 0.01), Galectin-3 (p = 0.001), HLA-DRA1 (p = 0.002), HLA-DQA1 (p = 0.04), HLA-DQB2 (p = 0.03), and HLA-DPA1 (p = 0.007) were associated with bad survival. We conclude that expression of the LAG ligands Galectin-3 and HLA class II strongly correlates with LAG3 expression and all are increased in UM with Monosomy 3/BAP1 loss. The distribution suggests a potential benefit of monoclonal antibodies against LAG3 or Galectin-3 as adjuvant treatment in patients with high-risk UM.
The American Joint Committee on Cancer (AJCC) staging system has been validated for use as a prognostic parameter in uveal melanoma (UM). We studied whether adding information regarding chromosome 3 ...and 8q status further enhances the prognostic value of this staging system.
We retrospectively studied a cohort of 522 patients who had been treated for UM in two different centers between 1999 and 2015. The mean follow-up time was 47.7 months. Cumulative incidence curves were generated and regression analyses were performed for different combinations of AJCC staging and chromosome status. Death due to UM metastases was the primary endpoint.
In AJCC stage I cases, only patients with monosomy 3 as well as chromosome 8q gain died due to UM metastases (P < 0.001). Among patients with stage II and III tumors, those with monosomy 3 plus gain of chromosome 8q had the worst prognosis, whereas the clinical outcome of those with only one of these aberrations was intermediate (P < 0.001). Patients without monosomy 3 and 8q gain showed favorable prognosis, independent of their tumor's AJCC stage. In cases with monosomy 3, 8q gain, or both, adding AJCC stage improved the predictive value. Multivariable regression analyses demonstrated that AJCC staging and chromosome 3 and 8q status contain independent information about survival status.
Combining information on AJCC staging and chromosome 3 and 8q status allows a more accurate prognostication in UM. We conclude that the prognostic value of the AJCC staging system can be improved by adding information regarding chromosome 3 and 8q status.
A three-dimensional numerical study is presented of the seasonal, semimonthly, and tidal-inertial cycles of temperature and density-driven circulation within the North Sea. The simulations are ...conducted using realistic forcing data and are compared with the 1989 data of the North Sea Project. Sensitivity experiments are performed to test the physical and numerical impact of the heat flux parameterizations, turbulence scheme, and advective transport. Parameterizations of the surface fluxes with the Monin-Obukhov similarity theory provide a relaxation mechanism and can partially explain the previously obtained overestimate of the depth mean temperatures in summer. Temperature stratification and thermocline depth are reasonably predicted using a variant of the Mellor-Yamada turbulence closure with limiting conditions for turbulence variables. The results question the common view to adopt a tuned background scheme for internal wave mixing. Two mechanisms are discussed that describe the feedback of the turbulence scheme on the surface forcing and the baroclinic circulation, generated at the tidal mixing fronts. First, an increased vertical mixing increases the depth mean temperature in summer through the surface heat flux, with a restoring mechanism acting during autumn. Second, the magnitude and horizontal shear of the density flow are reduced in response to a higher mixing rate. Thermal and salinity fronts generate a seasonal circulation pattern in the North Sea. Their impact on the horizontal temperature distributions is found to be in good agreement with the observations. It is shown that, in the absence of strong wind forcing, both the vertical temperature distribution and the thermal circulation experience semimonthly variations in response to the spring-neap cycle in tidal mixing. At spring tides, the surface mixed layers are shallower, in agreement with observations at two mooring stations, and the baroclinic circulation intensifies, whereas the opposite occurs at neaps.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Purpose
Orbital inflammation can be idiopathic or in the context of a specific disease and it can involve different anatomical orbital structures. On imaging, inflammatory disease is frequently ...mistaken for infection and malignant tumors, and its underlying cause is often not determined. Through this article we aim to improve orbital inflammation diagnosis and underlying inflammatory diseases recognition.
Methods
The imaging protocols and characteristics of orbital inflammation were reviewed.
Results
A decision tree for the evaluation of these patients is provided. First, a combination of clinical and radiological clues is used to recognize inflammation, in particular to differentiate it both from orbital infection and tumor. Subsequently, different radiological patterns are recognized, often allowing the differentiation of the several orbital inflammatory diseases.
Conclusion
The use of adequate imaging protocols and subsequent evaluation allow the recognition of an orbital lesion as inflammatory and the diagnosis of the underlying inflammatory disease. All in all, a proper treatment can be established, and at times, a biopsy can be avoided.
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