Digging deeper into lymphatic vessel formation in vitro and in vivo

Background Abnormal lymphatic vessel formation (lymphangiogenesis) is associated with different pathologies such as cancer, lymphedema, psoriasis and graft rejection. Lymphatic vasculature displays distinctive features than blood vasculature, and mechanisms underlying the formation of new lymphatic vessels during physiological and pathological processes are still poorly documented. Most studies on lymphatic vessel formation are focused on organism development rather than lymphangiogenic events occurring in adults. We have here studied lymphatic vessel formation in two in vivo models of pathological lymphangiogenesis (corneal assay and lymphangioma). These data have been confronted to those generated in the recently set up in vitro model of lymphatic ring assay. Ultrastructural analyses through Transmission Electron Microscopy (TEM) were performed to investigate tube morphogenesis, an important differentiating process observed during endothelial cell organization into capillary structures

Genetic diversity of Echinococcus multilocularis specimens isolated from Belgian patients with alveolar echinococcosis using EmsB microsatellites analysis.

The genetic diversity of Echinococcus multilocularis (E. multilocularis) specimens isolated from patients with alveolar echinococcosis (AE), is a major field of investigation to correlate with sources of infection, clinical manifestations and prognosis of the disease. Molecular markers able to distinguish samples are commonly used worldwide, including the EmsB microsatellite. Here, we report the use of the EmsB microsatellite polymorphism data mining for the retrospective typing of Belgian specimens of E. multilocularis infecting humans. A total of 18 samples from 16 AE patients treated between 2006 and 2021 were analyzed through the EmsB polymorphism. Classification of specimens was performed through a dendrogram construction in order to compare the similarity among Belgian samples, some human referenced specimens on the EWET database (EmsB Website for the Echinococcus Typing) and previously published EmsB profiles from red foxes circulating in/near Belgium. According to a comparison with human European specimens previously genotyped in profiles, the 18 Belgian ones were classified into three EmsB profiles. Four specimens could not be assigned to an already known profile but some are near to EWET referenced samples. This study also highlights that some specimens share the same EmsB profile with profiles characterized in red foxes from north Belgium, the Netherlands, Luxembourg and French department near to the Belgian border. Furthermore, Belgian specimens present a genetic diversity and include one profile that don't share similarities with the ones referenced in the EWET database. However, at this geographical scale, there is no clear correlation between EmsB profiles and geographical location. Further studies including additional clinical samples and isolates from foxes and rodents of south Belgium are necessary to better understand the spatial and temporal circumstances of human infections but also a potential correlation between EmsB profiles and parasite virulence

Inflammation-Generated Extracellular Matrix Fragments Drive Lung Metastasis

Mechanisms explaining the propensity of a primary tumor to metastasize to a specific site still need to be unveiled, and clinical studies support a link between chronic inflammation and cancer dissemination to specific tissues. Using different mouse models, we demonstrate the role of inflammation-generated extracellular matrix fragments ac-PGP (N-acetyl-proline-glycine-proline) on tumor cells dissemination to lung parenchyma. In mice exposed to cigarette smoke or lipopolysaccharide, lung neutrophilic inflammation produces increased levels of MMP-9 (matrix metalloproteinase 9) that contributes to collagen breakdown and allows the release of ac-PGP tripeptides. By silencing CXCR2 gene expression in tumor cells, we show that these generated ac-PGP tripeptides exert a chemotactic activity on tumor cells in vivo by binding CXCR2

Calculation of bovine haemoglobin oxygen saturation by algorithms integrating age, haemoglobin content, blood pH, partial pressures of oxygen and carbon dioxide in the blood, and temperature.

In human and veterinary medicine, arterial and venous haemoglobin oxygen saturations are often used to estimate the severity of a disease and to guide therapeutic decisions. In veterinary medicine, haemoglobin oxygen saturation (SO(2)) is usually calculated using a blood gas analyser and algorithms developed for humans. It is possible, therefore, that the values obtained in animals may be distorted, particularly in animals with a high haemoglobin oxygen affinity, like young calves. In order to verify this hypothesis, we compared the arterial (SaO(2)) and venous (SvO(2)) haemoglobin oxygen saturations calculated using three different algorithms, and the oxygen exchange fraction (OEF) at the tissue level, which is the degree of haemoglobin desaturation between arterial and venous blood (SaO(2)-SvO(2)), with the values obtained from the whole bovine oxygen equilibrium curve (OEC) determined by a reference method. The blood gas analysers underestimated SvO(2) values; consequently, the OEF was overestimated (by about 10%). Two methods of reducing these errors were assessed. As the haemoglobin oxygen affinity decreases during the first month of life in calves a relationship between PO(2) at 50% haemoglobin saturation (P50) and age was established in order to correct the calculated values of venous and arterial SO(2), taking into account the estimated position of the OEC. This method markedly reduced the error for SvO(2) and OEF. Secondly, the SO(2) was calculated using a mathematical model taking into account the age of the animal and the specific effects of pH, PCO(2), and temperature on the bovine OEC. Using this method, the mean difference between the OEF values calculated using the mathematical model and those calculated by the reference method was close to zero. The errors produced by blood gas analysers can thus be minimised in two ways: firstly, by simply introducing a P50 estimated from the age of the calf into the analyser before the measurement; and secondly, by calculating the SO(2) using a mathematical model applied to the bovine OEC

Digging deeper into lymphatic vessel formation <it>in vitro </it>and <it>in vivo</it>

Abstract Background Abnormal lymphatic vessel formation (lymphangiogenesis) is associated with different pathologies such as cancer, lymphedema, psoriasis and graft rejection. Lymphatic vasculature displays distinctive features than blood vasculature, and mechanisms underlying the formation of new lymphatic vessels during physiological and pathological processes are still poorly documented. Most studies on lymphatic vessel formation are focused on organism development rather than lymphangiogenic events occurring in adults. We have here studied lymphatic vessel formation in two in vivo models of pathological lymphangiogenesis (corneal assay and lymphangioma). These data have been confronted to those generated in the recently set up in vitro model of lymphatic ring assay. Ultrastructural analyses through Transmission Electron Microscopy (TEM) were performed to investigate tube morphogenesis, an important differentiating process observed during endothelial cell organization into capillary structures. Results In both in vivo models (lymphangiogenic corneal assay and lymphangioma), migrating lymphatic endothelial cells extended long processes exploring the neighboring environment and organized into cord-like structures. Signs of intense extracellular matrix remodeling were observed extracellularly and inside cytoplasmic vacuoles. The formation of intercellular spaces between endothelial cells led to tube formation. Proliferating lymphatic endothelial cells were detected both at the tips of sprouting capillaries and inside extending sprouts. The different steps of lymphangiogenesis observed in vivo are fully recapitulated in vitro, in the lymphatic ring assay and include: (1) endothelial cell alignment in cord like structure, (2) intracellular vacuole formation and (3) matrix degradation. Conclusions In this study, we are providing evidence for lymphatic vessel formation through tunneling relying on extensive matrix remodeling, migration and alignment of sprouting endothelial cells into tubular structures. In addition, our data emphasize the suitability of the lymphatic ring assay to unravel mechanisms underlying lymphangiogenesis.</p

Inadequate detection of accessory spleens and splenosis with laparoscopic splenectomy : A shortcoming of the laparoscopic approach in hematologic diseases

BACKGROUND: The ultimate goal of surgery for hematological disorders is the complete removal of both the spleen and accessory spleens in order to avoid recurrence of the disease. Whereas splenectomy by open surgery provides excellent results, the validity of laparoscopic splenectomy in this regard remains unknown. OBJECTIVE: The purpose of this study was to evaluate the detection of accessory spleens during laparoscopic splenectomy for hematologic diseases. METHODS: We therefore evaluated the pre-, intra-, and postoperative detection of accessory spleens in a consecutive series of 18 patients treated by elective laparoscopic splenectomy for hematological diseases by using computed tomography (CT) and denatured red blood cell scintigraphy (DRBCS). RESULTS: Preoperative CT, DRBCS, and laparoscopic exploration detected 25%, 25%, and 75% of accessory spleens, respectively. At time of laparoscopy, 16 accessory spleens were detected in seven of the 18 patients (41%). In two patients (11%), laparoscopic exploration failed to detect accessory spleens, whereas preoperative CT (one case) and DRBCS (one case) did reveal them. Postoperatively, during a mean follow-up of 28 months (median, 24; range, 12-44 months), nine patients (50%) showed persistence of splenic tissue by DRBCS, and three of them had signs of disease recurrence. CONCLUSIONS: This prospective clinical study suggests that elective laparoscopic surgery for hematological diseases does not allow complete detection of accessory spleens. Moreover, after such a laparoscopic approach, residual splenic tissue is detectable in half of the patients during the follow-up

VEGF-A is an important factor implicated in LEC stimulation by MSC conditioned medium.

<p>(A, B) The trapping of VEGF-A by the addition of soluble receptors-1 and -2 decreased MSC conditioned medium-induced LEC proliferation, measured by WST-1 assay (A) and migration in a Boyden chamber assay (B). *** P<0.001. (C) Specific inhibition of VEGFR-2 with ZM 323881 10 nM decreased MSC conditioned medium-induce LEC proliferation measured by WST-1 assay. *** P<0.001. (D) Phosphorylation of VEGFR-2 and ERK1/2 analyzed by western blotting on LEC treated or not with soluble VEGF receptors or ZM 323881 10 nM.</p

BM-MSC stimulate lymphangiogenesis <i>in vitro</i>.

<p>(A) Lymphatic rings were cultured during 5 days alone (CTR) or in presence of BM-MSC spheroids (+MSC spheroids), and during 10 days with control medium (CTR2) or with MSC conditioned medium (MSC CM) prepared as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0106976#s2" target="_blank">material and methods</a> section. For quantification, a grid corresponding to successive increments at fixed intervals of explant boundary was used on binarized images and the number of microvessel–grid intersections (N_i) was quantified on binarized images. Quantification was performed at a distance of 0.5 mm and results are expressed as the number of intersections (N_i) plotted as a function of distance (mm) to the lymphatic ring. Bar: 500 µm. * P<0.05. (B, C) MSC conditioned medium significantly stimulates the proliferation and migration of LEC <i>in vitro</i> as compared to control medium. (B) Proliferation rate was measured by a WST-1 and BrdU incorporation assays. ** P<0.01, *** P<0.001. (C) Migration was measured in a Boyden chamber assay. *** P<0.001.</p