Single and combined impacts of irradiation and surgery on lymphatic vasculature and fibrosis associated to secondary lymphedema.

Lymphedema (LD) refers to a condition of lymphatic dysfunction associated with excessive fluid accumulation, fibroadipose tissue deposition and swelling. In industrialized countries, LD development mainly results from a local disruption of the lymphatic network by an infection or cancer-related surgery (secondary LD). In the absence of efficient therapy, animal models are needed to decipher the cellular and molecular mechanisms underlying LD and test putative drugs. In this study, we optimized and characterized a murine model of LD that combines an irradiation of the mice hind limb and a radical surgery (lymph node resection associated to lymphatic vessel ligation). We investigated the respective roles of irradiation and surgery in LD formation by comparing their impacts, alone or in combination (with different intervention sequences), on eight different features of the pathology: swelling (paw thickness), indocyanine green (ICG) clearance, lymphatic vasculature remodeling, epidermal and dermal thickening, adipocyte accumulation, inflammatory cell infiltration and collagen deposition. This study supports the importance of radiation prior to surgery to experimentally induce a rapid, severe and sustained tissue remodeling harboring the different hallmarks of LD. We provide the first experimental evidence for an excessive deposition of periostin (POSTN) and tenascin-C (TNC) in LD. Through a computerized method of digital image quantification, we established the spatial map of lymphatic expansion, as well as collagen, POSTN and TNC deposition in papillary and reticular dermis of lymphedematous skins. This mouse model is available to study the patho-physiology of LD and test potential therapeutic targets.

Synergism between vascular endothelial growth factor and placental growth factor contributes to angiogenesis and plasma extravasation in pathological conditions.

Vascular endothelial growth factor (VEGF) stimulates angiogenesis by activating VEGF receptor-2 (VEGFR-2). The role of its homolog, placental growth factor (PlGF), remains unknown. Both VEGF and PlGF bind to VEGF receptor-1 (VEGFR-1), but it is unknown whether VEGFR-1, which exists as a soluble or a membrane-bound type, is an inert decoy or a signaling receptor for PlGF during angiogenesis. Here, we report that embryonic angiogenesis in mice was not affected by deficiency of PlGF (Pgf-/-). VEGF-B, another ligand of VEGFR-1, did not rescue development in Pgf-/- mice. However, loss of PlGF impaired angiogenesis, plasma extravasation and collateral growth during ischemia, inflammation, wound healing and cancer. Transplantation of wild-type bone marrow rescued the impaired angiogenesis and collateral growth in Pgf-/- mice, indicating that PlGF might have contributed to vessel growth in the adult by mobilizing bone-marrow-derived cells. The synergism between PlGF and VEGF was specific, as PlGF deficiency impaired the response to VEGF, but not to bFGF or histamine. VEGFR-1 was activated by PlGF, given that anti-VEGFR-1 antibodies and a Src-kinase inhibitor blocked the endothelial response to PlGF or VEGF/PlGF. By upregulating PlGF and the signaling subtype of VEGFR-1, endothelial cells amplify their responsiveness to VEGF during the 'angiogenic switch' in many pathological disorders.

Altered expression of angiogenesis and lymphangiogenesis markers in the uninvolved skin of plaque-type psoriasis.

BACKGROUND: Vascular alterations are significant events in the pathomechanism of psoriasis. A disorder in the mechanisms regulating skin angiogenesis and lymphangiogenesis could participate in the pathogenesis of the disease. OBJECTIVES: To quantify differences in the expression of angiogenesis and lymphangiogenesis growth factors, receptors, coreceptors as well as their antagonists in the uninvolved skin of patients with psoriasis compared with the skin of nonpsoriatic volunteers. METHODS: Skin biopsies were collected from the involved skin of 13 patients with untreated plaque-type psoriasis, from their nonlesional skin at distance from the lesions and from the skin of 16 healthy volunteers. The mRNA steady-state level of keratins 10, 14 and 16, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), vimentin, collagen I and IV, proliferating cell nuclear antigen, the various splice variants of vascular endothelial growth factor, VEGF-A, VEGF-C and VEGF-D, their receptors VEGFR1, VEGFR2 and VEGFR3, neuropilin (NRP)-1 and its soluble forms, NRP-2, semaphorin 3A and prox-1, was measured by reverse transcription-polymerase chain reaction. Immunohistochemistry was performed for Ki-67, von Willebrand factor and D2-40. Blood and lymphatic vessel density, area and distance from epidermis were estimated by morphological analysis coupled to an original computer-assisted method of quantification. RESULTS: Skin from healthy volunteers and nonlesional skin from patients with psoriasis displayed similar histological, morphometric and proliferative features. However, a significant overexpression of VEGFR3, the VEGF-A isoform VEGF121, soluble 12 NRP-1 and GAPDH was observed in the nonlesional psoriatic skin as compared with that of normal volunteers. CONCLUSIONS: These data point to significant differences in the blood and lymphatic vascular transcriptome between the clinically normal-appearing skin of patients with psoriasis and the skin of volunteers without psoriasis.

Two methods of random seed generation to avoid over-segmentation with stochastic watershed: application to nuclear fuel micrographs.

A stochastic version of the watershed algorithm is obtained by choosing randomly in the image the seeds from which the watershed regions are grown. The output of the procedure is a probability density function corresponding to the probability that each pixel belongs to a boundary. In the present paper, two stochastic seed-generation processes are explored to avoid over-segmentation. The first is a non-uniform Poisson process, the density of which is optimized on the basis of opening granulometry. The second process positions the seeds randomly within disks centred on the maxima of a distance map. The two methods are applied to characterize the grain structure of nuclear fuel pellets. Estimators are proposed for the total edge length and grain number per unit area, L(A) and N(A), which take advantage of the probabilistic nature of the probability density function and do not require segmentation.

X-ray microtomography studies of tannin-derived organic and carbon foams.

Tannin-based rigid foams of different bulk densities and their carbonized counterparts were investigated for the first time by X-ray microtomography. This method allowed acquisition of three-dimensional pictures of such highly porous materials. Through mathematical treatment of the images, extremely useful physical characteristics such as porosity, fraction of open cells, connectivity, tortuosity, and pore-size distribution were determined as a function of the foam's density. The obtained information was compared with independent data derived from pycnometry measurements and scanning electron microscope image analysis. The agreement was shown to be acceptable in the limit of the accuracy of the laboratory microtomograph (4 microm). Moreover, recalculating properties like permeability were shown to be quite possible based on the results of standard microtomography data.

Persistence of an intact endometrial matrix and vessels structure in women exposed to VA-2914, a selective progesterone receptor modulator.

BACKGROUND: VA-2914 is a selective progesterone receptor modulator with potential contraceptive activity that induces amenorrhea, whereas progestins cause endometrial spotting and bleeding. This abnormal bleeding due to progestins is a consequence of focal stromal proteolysis by an increase in naked vessel size and density. OBJECTIVE: Our objective was to quantify the effects of VA-2914 on endometrial vascularization, fibrillar matrix, and vascular endothelial growth factor (VEGF)-A expression in endometrial biopsies from 41 women before and after 12 wk daily treatment with a placebo, or 2.5, 5, or 10 mg VA-2914. METHODS: Collagen fibrillar network was stained by silver impregnation. Vessel area, density, and structure were quantified with a computer-assisted image analysis system after double immunostaining using an anti-von Willebrand factor (endothelial cells) and an anti-alpha smooth muscle actin (vascular smooth muscle cells) marker antibody. VEGF-A mRNAs were quantified by RT-PCR and localized by immunohistochemistry. RESULTS: The endometrial vessels, collagen network, and mRNA levels of VEGF-A were identical during the luteal phase at baseline and in VA-2914 treated women. VEGF-A distribution was unchanged. CONCLUSIONS: VA-2914 does not alter the endometrial matrix and cells, and does not modify the endometrial vessel morphology as compared with baseline biopsies.

Novel application assigned to toluquinol: inhibition of lymphangiogenesis by interfering with VEGF-C/VEGFR-3 signalling pathway.

BACKGROUND AND PURPOSE: Lymphangiogenesis is an important biological process associated with the pathogenesis of several diseases, including metastatic dissemination, graft rejection, lymphoedema and other inflammatory disorders. The development of new drugs that block lymphangiogenesis has become a promising therapeutic strategy. In this study, we investigated the ability of toluquinol, a 2-methyl-hydroquinone isolated from the culture broth of the marine fungus Penicillium sp. HL-85-ALS5-R004, to inhibit lymphangiogenesis in vitro, ex vivo and in vivo. EXPERIMENTAL APPROACH: We used human lymphatic endothelial cells (LECs) to analyse the effect of toluquinol in 2D and 3D in vitro cultures and in the ex vivo mouse lymphatic ring assay. For in vivo approaches, the transgenic Fli1:eGFPy1 zebrafish, mouse ear sponges and cornea models were used. Western blotting and apoptosis analyses were carried out to search for drug targets. KEY RESULTS: Toluquinol inhibited LEC proliferation, migration, tubulogenesis and sprouting of new lymphatic vessels. Furthermore, toluquinol induced apoptosis of LECs after 14 h of treatment in vitro, blocked the development of the thoracic duct in zebrafish and reduced the VEGF-C-induced lymphatic vessel formation and corneal neovascularization in mice. Mechanistically, we demonstrated that this drug attenuates VEGF-C-induced VEGFR-3 phosphorylation in a dose-dependent manner and suppresses the phosphorylation of Akt and ERK1/2. CONCLUSIONS AND IMPLICATIONS: Based on these findings, we propose toluquinol as a new candidate with pharmacological potential for the treatment of lymphangiogenesis-related pathologies. Notably, its ability to suppress corneal neovascularization paves the way for applications in vascular ocular pathologies.

Study of the connectivity properties of Bioglass -filled polylactide foam scaffolds by image analysis and impedance spectroscopy.

The porous structure of two series of poly(D,L-lactide)/Bioglass composite foams prepared by thermal-induced phase separation was investigated by image analysis and impedance spectroscopy. Polymer solutions of either low or high molecular weight containing different concentrations (up to 50 wt.%) of Bioglass particles of mean particle size d < 5 microm were studied. The morphology of both macro- and micropores was studied by scanning electron microscopy and image analysis of both neat and composite foams (containing 10-50 wt.% Bioglass). The pore connectivity of both neat polymer and composite foams was characterized by impedance spectroscopy in relation with their transport properties. The influence of the foam composition (i.e., polymer molecular weight and concentration of Bioglass on pore microstructure was studied using these non-destructive methods. It was found that addition of Bioglass particles has a pronounced effect on pore orientation, leading to increasing loss of order of pore structure, especially for low-molecular weight PDLLA foams.

Estetrol is a weak estrogen antagonizing estradiol-dependent mammary gland proliferation.

Estetrol (E4) is a natural estrogen produced exclusively by the human fetal liver during pregnancy. Its physiological activity remains unknown. In contrast to ethinyl estradiol and estradiol (E2), E4 has a minimal impact on liver cell activity and could provide a better safety profile in contraception or hormone therapy. The aim of this study was to delineate if E4 exhibits an activity profile distinct from that of E2 on mammary gland. Compared with E2, E4 acted as a low-affinity estrogen in both human in vitro and murine in vivo models. E4 was 100 times less potent than E2 to stimulate the proliferation of human breast epithelial (HBE) cells and murine mammary gland in vitro and in vivo respectively. This effect was prevented by fulvestrant and tamoxifen, supporting the notion that ERα (ESR1) is the main mediator of the estrogenic effect of E4 on the breast. Interestingly, when E4 was administered along with E2, it significantly antagonized the strong stimulatory effect of E2 on HBE cell proliferation and on the growth of mammary ducts. This study characterizes for the first time the impact of E4 on mammary gland. Our results highlight that E4 is less potent than E2 and exhibits antagonistic properties toward the proliferative effect of E2 on breast epithelial cells. These data support E4 as a potential new estrogen for clinical use with a reduced impact on breast proliferation.

Alignment of glial cells stimulates directional neurite growth of CNS neurons in vitro.

Olfactory ensheathing cells (OECs) together with olfactory nerve fibroblasts (ONFs) and neonatal astrocytes are potent stimulators of neurite growth in adulthood and during development, respectively. Since it is known that alignment of glial cells is important for the correct outgrowth of axon tracts, it was hypothesized that the alignment of glial cells stimulates directional and enhanced neurite outgrowth. Adult OEC/ONF and neonatal astrocytes were cultured either on biodegradable poly(d,l)-lactide matrices or in Petri dishes for 4 days. Thereafter neonatal cerebral cortical neurons were added. After a 2-days coculture period the cultures were fixed and processed for a combined MAP-2 and phosphorylated neurofilament (RT97) staining. The neurite growth (neurite elongation and neurite formation) and the neurite direction were assessed. We show that (1). OEC/ONF cultures are more potent in stimulating the length of the longest neurite of cocultured neurons, (2). alignment of glial is achieved in vitro on our biomatrices, (3). aligned glial/biomatrix complexes do not enhance neurite growth, and (4). aligned glial/biomatrix complexes direct neurite outgrowth. These data have significant implications for in vivo experiments focusing on glial transplantation. Transplanting glial/biomatrix complexes may stimulate the directional regrowth of severed axons across a lesion site.

Image analysis of the axonal ingrowth into poly(D,L-lactide) porous scaffolds in relation to the 3-D porous structure.

Porous polymer scaffolds are promising materials for neural tissue engineering because they offer valuable three-dimensional (3-D) supports for the in vitro and in vivo axonal growth and tissue expansion. At the time being, how the in vivo neuronal cell development depends on the scaffold 3-D architecture is unknown. Therefore, scanning electron micrographs of longitudinal sections of porous polylactide scaffolds and immunohistological sections of these scaffolds after implantation and neurofilament staining have been studied by image analysis. Pore orientation and axonal ingrowth have been investigated by spectral analysis on gray level SEM images. Binary image processing has been carried out and the binary images have been studied by spectral analysis in order to estimate the possible effect of the image noise on the real pattern. In addition to axonal orientation, density and length distribution of the regenerated axons into the polymer scaffold have been measured. Dependence of the axonal ingrowth on the 3D-polymer scaffold has been discussed on the basis of the collected data.

Preparation of macroporous biodegradable poly(L-lactide-co-epsilon-caprolactone) foams and characterization by mercury intrusion porosimetry, image analysis, and impedance spectroscopy.

Two poly(L-lactide-co-epsilon-caprolactone) random copolymers containing 5 and 40 mol % of epsilon-CL, namely P(LA-co-CL(5)) and P(LA-co-CL(40)), respectively, have been made macroporous by freeze-drying solutions in dimethylcarbonate. Most of the freeze-dried foams, prepared by varying polymer concentration and cooling rate, exhibited two main pore populations: (1). longitudinally oriented tube-like macropores with diameters >or=100 microm, and (2). interconnected micropores (10-100 microm). Pore characteristics, including macropore density, mean diameter, and interdistance, as well as micropore density, area, and shape, were determined by image analysis of scanning electron micrographs in order to study the influence of processing and formulation parameters on foam structure and properties. The pore orientation and the 3-D texture also were studied by image analysis and impedance spectroscopy. In the case of the P(LA-co-CL(5)), the macropore diameter increased with the cooling rate while the micropore diameter decreased. The micropores also became more circular when the cooling rate was increased. The pore size and morphology of the P(LA-co-CL(40)) were quite unchanged by varying the cooling rate. All the other conditions being the same, the P(LA-co-CL(5)) foams were better organized than the P(LA-co-CL(40)) foams, and pore orientation was improved at the higher cooling rate. Pore size and morphology also can be controlled by changing the polymer concentration (Cp), as we showed by studying P(LA-co-CL(5)) foams prepared by freeze-drying solutions in the 1-10 w/v % Cp range. Macropore density, average diameter, and interdistance of P(LA-co-CL(5)) foams increased with Cp, but the micropore characteristics remained almost unchanged no matter the Cp. The reliability of the characterization methods has been discussed, with special attention to mercury intrusion porosimetry, which is used primarily for measurement of pore volume and pore size distribution. However, this technique is reported here as a destructive and unreliable method for the characterization of fragile P(LA-co-CL(40)) foams. This study shows that image analysis and impedance spectroscopy can give reliable information relative to the pore morphology and anisotropy of freeze-dried foams.

Is fractal geometry useful in medicine and biomedical sciences?

Fractal geometry has become very useful in the understanding of many phenomena in various fields such as astrophysics, economy or agriculture and recently in medicine. After a brief intuitive introduction to the basis of fractal geometry, the clue is made about the correlation between Df and the complexity or the irregularity of a structure. However, fractal analysis must be applied with certain caution in natural objects such as bio-medical ones. The cardio-vascular system remains one of the most important fields of application of these kinds of approach. Spectral analysis of the R-R interval, morphology of the distal coronary arteries constitute two examples. Other very interesting applications are founded in bacteriology, medical imaging or ophthalmology. In our institution, we apply fractal analysis in order to quantitate angiogenesis and other vascular processes.

Whole slide quantification of stromal lymphatic vessel distribution and peritumoral lymphatic vessel density in early invasive cervical cancer: a method description.

Peritumoral Lymphatic Vessel Density (LVD) is considered to be a predictive marker for the presence of lymph node metastases in cervical cancer. However, when LVD quantification relies on conventional optical microscopy and the hot spot technique, interobserver variability is significant and yields inconsistent conclusions. In this work, we describe an original method that applies computed image analysis to whole slide scanned tissue sections following immunohistochemical lymphatic vessel staining. This procedure allows to determine an objective LVD quantification as well as the lymphatic vessel distribution and its heterogeneity within the stroma surrounding the invasive tumor bundles. The proposed technique can be useful to better characterize lymphatic vessel interactions with tumor cells and could potentially impact on prognosis and therapeutic decisions.

Higher sensitivity of Adamts12-deficient mice to tumor growth and angiogenesis.

ADAMTS (a disintegrin and metalloproteinase domain with thrombospondin motifs) constitute a family of endopeptidases related to matrix metalloproteinases. These proteases have been largely implicated in tissue remodeling and angiogenesis associated with physiological and pathological processes. To elucidate the in vivo functions of ADAMTS-12, we have generated a knockout mouse strain (Adamts12(-/-)) in which Adamts12 gene was deleted. The mutant mice had normal gestations and no apparent defects in growth, life span and fertility. By applying three different in vivo models of angiogenesis (malignant keratinocyte transplantation, Matrigel plug and aortic ring assays) to Adamts12(-/-) mice, we provide evidence for a protective effect of this host enzyme toward angiogenesis and cancer progression. In the absence of Adamts-12, both the angiogenic response and tumor invasion into host tissue were increased. Complementing results were obtained by using medium conditioned by cells overexpressing human ADAMTS-12, which inhibited vessel outgrowth in the aortic ring assay. This angioinhibitory effect of ADAMTS-12 was independent of its enzymatic activity as a mutated inactive form of the enzyme was similarly efficient in inhibiting endothelial cell sprouting in the aortic ring assay than the wild-type form. Altogether, our results show that ADAMTS-12 displays antiangiogenic properties and protect the host toward tumor progression.

Quantification of in vivo tumor invasion and vascularization by computerized image analysis.

The matrix-inserted surface transplantation model is an in vivo assay used to analyse the kinetics of tumor-vessel interactions during different stages of skin carcinoma progression. This system allows the study of host-tumor interface, i.e. penetration of tumor cells into normal host tissue as well as infiltration of normal host cells into the tumor. In the present study, image analysis algorithms for processing and quantifying the extent of such migratory and tissue remodeling events are presented. The proposed method is non-parametric and its originality lies in its particularity to take into account the specific geometry of tumor-host interface. This methodology is validated by evaluating the contribution of matrix metalloproteases (MMPs) in skin carcinoma invasion and vascularization through pharmacological and genetic approaches.

Non-destructive characterization of deer (Cervus Elaphus) antlers by X-ray microtomography coupled with image analysis.

X-ray microtomography coupled with image analysis was tested as a non-destructive alternative method for the textural characterization of the trabecular part of deer antlers (Cervus Elaphus). As gas adsorption and mercury intrusion cannot be applied on this soft and spongy material, its pore texture was, up to now, determined from histological sections that give only two-dimensional information. In this work, X-ray microtomography is used to scan entire or half pieces of antlers and three-dimensional image analysis is performed in order to assess the differences between samples collected at various antler locations. Results clearly show a porosity profile along the sample diameter. The pore size distribution is showed to be dependent on the sample original site.

Image analysis of X-ray microtomograms of soft materials during convective drying: 3D measurements.

Drying dewatered sludge leads to a complex three-dimensional porous structure. Moreover, this operation is dependent on the way the material is processed. In this study, textural changes of sludge extrudates submitted to convective drying are followed by a 3D image analysis of reconstructed X-ray microtomograms. To achieve this goal, two different wastewater sludges collected in wastewater treatment plant after the thickening step and dewatered in the laboratory are used. It is showed that the evolution of the 3D-crack ratio vs. the residual water content evolves following a hyperbolic law. The 3D opening crack size distribution reveals two different types of pore development, i.e. a continuous pore size evolution for one sludge and the sudden appearance of cracks for the other sludge.

Prediction of success and failure of behavior modification as treatment for dental anxiety.

Behavior modification techniques are effective in the treatment of extreme dental anxiety, but their success is by no means absolute. In the present article, the Corah Dental Anxiety Scale (DAS), the self-report symptom inventory SCL-90R and a questionnaire accessing subjects' daydreaming styles (the Short Imaginal Process Inventory) were used to develop possible predictive measures for success and failure of behavior modification as a treatment for dental fear. The patients' level of distractibility and mind wandering, initial dental anxiety and somatization significantly predicted the success of therapy. The odds ratio indicated that the risk of therapy failure increased about 11 times with an increase of one scale of the Poor Attention Control Scale, about three times with an increase of one level of the mean DAS score, and 0.17 times with an increase of one level of somatization. The predictive value of the chosen scales was 80%. Thus, the use of these scales as part of an initial admittance process for patients who suffer from dental anxiety can enhance our ability to better recognize patients who are prone to fail behavior therapy as treatment for their problem, and enable their referral for other possible modes of treatment.