Number Of Stromal Cells Research Articles

Endometrial cell counts in recurrent miscarriage: a comparison of counting methods

Studies of uterine natural killer (uNK) cells require reliable measurements of uNK cell density among diverse endometrial tissue. The aim of this study was to compare cell counting manually with two computer-aided methods based on a public domain software package, ImageJ. Immunohistochemistry (IHC) of CD56(+) uNK cells was performed on endometrium from recurrent miscarriage patients. Numbers of stromal cells per high-power field (HPF) were counted by two observers using: (i) manual tally counter and graticule; (ii) ImageJ 'point picker' tool; and (iii) ImageJ 'particle analysis' tool. Coefficients of variation (CV) and Bland-Altman plots were used to evaluate interobserver differences. Evaluation of %uNK using ImageJ particle analysis for stromal cell counts and point picker tool for uNK counts was undertaken. Point picker and particle analysis were significantly better than manual counting [interobserver CVs mean (standard deviation) 6.1% (3.3%); 4.7% (3.9%), 8.2% (6.5%), respectively]. Mean inter- and intra-observer CVs for %uNK were 10.3% (6.6%), 8.5% (4.9%) and 6.8% (4.3%), respectively. Bland-Altman analysis revealed no systematic differences in cell counts with the number of cells in the image for each method. Compared to manual cell counting, computer-aided image analysis yields more reproducible results for the assessment of uNK cells density using IHC.

Expression of autotaxin and acylglycerol kinase in proliferative vitreoretinal epiretinal membranes

Lysophosphatidic acid (LPA)/LPA(1) receptor pathway is involved in inflammation, angiogenesis and fibrosis. This study was conducted to analyse the expression of LPA-producing enzymes, autotaxin (ATX) and acylglycerol kinase (AGK) and LPA(1) receptor, in proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR) epiretinal membranes. Nine active and 13 inactive membranes from patients with PDR and 21 membranes from patients with PVR were studied by immunohistochemistry. In PDR membranes, vascular endothelial cells expressed ATX and AGK in 16 and 19 membranes, respectively. Stromal cells expressed ATX and AGK in 19 and 22 membranes, respectively. Immunoreactivity for LPA(1) receptor was noted in vascular endothelial cells and stromal cells in the five membranes stained for LPA(1) receptor. Numbers of blood vessels and stromal cells expressing CD34, ATX and AGK were significantly higher in active membranes than in inactive membranes. Significant correlations were detected between number of blood vessels expressing the panendothelial cell marker CD34 and number of blood vessels and stromal cells expressing ATX and AGK. In PVR membranes, spindle-shaped myofibroblasts expressing α-smooth muscle actin co-expressed ATX, AGK and LPA(1) receptor. The LPA/LPA(1) receptor pathway may be involved in inflammatory, angiogenic and fibrotic responses in proliferative vitreoretinal disorders.

Non-Canonical NF-Kb Signaling Regulates Hematopoietic Stem Cell Self-Renewal and Microenvironment Interactions

Abstract 859RelB and NF-kB2 are the main effectors of NF-kB non-canonical signaling and play critical roles in many physiological processes. However, their role in hematopoietic stem/progenitor cell (HSPC) maintenance has not been characterized. To investigate this, we generated RelB/NF-kB2 double-knockout (dKO) mice and found that dKO HSPCs have profoundly impaired engraftment and self-renewal activity after transplantation into wild-type recipients. Transplantation of wild-type bone marrow cells into dKO mice to assess the role of the dKO microenvironment showed that wild-type HSPCs cycled more rapidly, were more abundant, and had developmental aberrancies: increased myeloid and decreased lymphoid lineages, similar to dKO HSPCs. Notably, when these wild-type cells were returned to normal hosts, these phenotypic changes were reversed, indicating a potent but transient phenotype conferred by the dKO microenvironment. However, dKO bone marrow stromal cell numbers were reduced, and bone-lining niche cells supported less HSPC expansion than controls. Further, increased dKO HSPC proliferation was associated with impaired expression of niche adhesion molecules by bone-lining cells and increased inflammatory cytokine expression by bone marrow cells. Thus, RelB/NF-kB2 signaling positively and intrinsically regulates HSPC self-renewal and maintains stromal/osteoblastic niches and negatively and extrinsically regulates HSPC expansion and lineage commitment through the marrow microenvironment. Disclosures:No relevant conflicts of interest to declare.

Re-establishing pluripotency in adult cells derived from breast stromal tissue.

227 Background: Recent advances in pluripotent stem cell biology offer patient-specific disease models to investigate in vitro mechanisms of tumorigenesis. Induced pluripotent stem (iPS) cells were originally derived by reprogramming of human dermal fibroblasts through ectopic expression of pluripotency–associated transcription factors. A limitation to the use of dermal fibroblasts as the starting cell type for reprogramming is that it usually takes weeks to expand cells from a single biopsy, and the efficiency of the process is very low. In contrast, a large number of adipose-derived mesenchymal stromal cells (Ad-MSCs) can be easily obtained from the stroma of human breast tissue, without the time-consuming steps of cell expansion. Here we investigated the ability to induce pluripotency in committed, Ad-MSCs derived from the stroma of breast tissue. Methods: The aim of this study is to investigate the potential of using Ad-MSCs derived from surgically discarded breast stromal tissue to generate human iPS. Discarded tissue during surgical procedures was processed in vitro and Ad-MSCs were derived. These Ad-MSCs were then used to generate iPS cells by ectopic expression of “Yamanaka’s cocktail” containing OCT4, SOX2, KLF4 and c-MYC. Results: The success rate in generating iPS cells from human Ad-MSCs derived from breast stromal tissue is very high compared to the use of dermal fibroblasts. In our study, almost all human Ad-MSC cell lines can be reprogrammed into iPS cells, which share the same characteristics as skin fibroblast-derived iPS cells and human embryonic stem cells in their morphology, gene expression profile and differentiation capacities. Conclusions: We are now optimizing this approach and making it more clinically relevant by adopting an integration-free method to deliver the reprogramming factors. The successful reprogramming of breast stromal-derived Ad-MSCs into iPS cells may provide a valuable source of patient-specific iPS cells to study the mechanism of tumorigenesis in patients with breast cancer.

Effects of different sera on adipose tissue-derived mesenchymal stromal cells

Current cell therapy protocols require considerable numbers of mesenchymal stromal cells (MSCs), which can be obtained only by in vitro expansion. The most important issue is a choice of optimal growth supplements for cell culture. Ideally, these should be of known composition, free of animal components and allow production of large homogenic populations of MSCs in a considerably short period of time. Since this standard has not been achieved to date, we aimed to assess the molecular responses of MSCs to different growth supplements commonly in use. MSCs were isolated from breast or abdominal adipose tissue and plated into DMEM supplemented with one of four different sera: fetal calf serum (FCS), pretested fetal calf serum (FCS-Sp), human allogeneic serum (HS) or artificial serum substitute (AS). MSCs cultivated with different serum supplements demonstrated distinct morphologies, high adipogenic and osteogenic differentiation potential and expressed characteristic antigens. Using real-time PCR, we found a large increase in PPARγ and Msx2 gene expression in both lines of proliferating MSCs cultivated with AS. We found that MSCs cultivated in the presence of different sera had similar global proteomic expression patterns, but comparisons of identified proteins revealed most differences in the MSCs cultivated with AS. Our results indicate that MSCs cultivated in the presence of FCS and HS display similar growth, differentiation, immunophenotypic and proteomic properties, while AS induces more profound changes in the physiology of MSCs, suggesting that further fundamental studies should be done before its introduction into clinical practice.

Mesenchymal Stromal Cells in Bronchoalveolar Lavage as Predictors of Bronchiolitis Obliterans Syndrome

Bronchoalveolar lavage fluid (BAL) from human lung allografts demonstrates the presence of a multipotent mesenchymal stromal cell population. However, the clinical relevance of this novel cellular component of BAL and its association with bronchiolitis obliterans syndrome (BOS), a disease marked by progressive airflow limitation secondary to fibrotic obliteration of the small airways, remains to be determined. In this study we investigate the association of number of mesenchymal stromal cells in BAL with development of BOS in human lung transplant recipients. Mesenchymal colony-forming units (CFUs) were quantitated in a cohort of 405 BAL samples obtained from 162 lung transplant recipients. Poisson generalized estimating equations were used to determine the predictors of BAL mesenchymal CFU count. Higher CFU counts were noted early post-transplantation; time from transplant to BAL of greater than 3 months predicted 0.4-fold lower CFU counts (P = 0.0001). BOS diagnosis less than or equal to 365 days before BAL was associated with a 2.11-fold higher CFU count (P = 0.02). There were 2.62- and 2.70-fold higher CFU counts noted in the presence of histologic diagnosis of bronchiolitis obliterans (P = 0.05) and organizing pneumonia (0.0003), respectively. In BAL samples obtained from BOS-free patients greater than 6 months post-transplantation (n = 173), higher mesenchymal CFU counts (≥10) significantly predicted BOS onset in both univariate (hazard ratio, 5.61; 95% CI, 3.03-10.38; P < 0.0001) and multivariate (hazard ratio, 5.02; 95% CI, 2.40-10.51; P < 0.0001) Cox regression analysis. Measurement of mesenchymal CFUs in the BAL provides predictive information regarding future BOS onset.

MT1-MMP Plays a Critical Role In the Modulation of Hematopoiesis.

AbstractAbstract 3851Specific niches, in which hematopoietic stem cells (HSCs) reside control the balance between HSC quiescence and self-renewal, yet little is known about the extrinsic signals provided by the niche and how these niche signals regulate such a balance. In the recent study, activation of the fibrinolytic pathway via matrix metalloproteinases (MMPs) including MMP-9 resulted in the release of kit ligand (KitL) in the BM niche. Membrane type 1-MMP (MT1-MMP) can activate MMP-9 in the process of mutual activation of MMP. It has already known that BM myeloablation with irradiation or anti-cancer drug induces MT1-MMP expression, but the role of MT1-MMP in hematopoiesis is not well-understood. We examined MT1-MMP deficient mice (MT1-MMP-/-) 12 days after birth. MT1-MMP-/- were suffering from pancytopenia, and are reduced numbers of bone marrow mononuclear cells (BMMCs), splenocytes and number of hematopoietic progenitor cells in the BM although the number of HSCs in BM showed no significant difference. BM cytospins from MT1-MMP-/- mice showed mild erythropoietic disturbance and severer impairment of myelopoiesis. Interestingly, a powerful hematopoietic factor, Kit-ligand (KitL) levels were significantly lower in MT1-MMP-/- mice than wild type. MT1-MMP knockdown by shRNA or/and siRNA impaired KitL expression and secretion in transfected stroma cells compared to Mock controls, demonstrating that reduced KitL plasma levels were due to impaired release/production and not due to reduced numbers of stromal cells in MT1-MMP-/-. Similarly, impaired proliferation and differentiation of MT1-MMP-/- BMMCs in vitro could be restored by exogenous sKitL. Others and we reported that BM ablation induces the production of stromal cell-derived factor-1 (SDF-1; CXCL12), which plays a key role in stem cell homing and B-cell lymphopoiesis. Reduced SDF-1 expression was observed in BMMCs of MT1-MMP-/- mice and genetic knockdown of MT1-MMP resulted in lower SDF-1 expression both on a transcriptional and protein level. BMMCs of MT1-MMP-/- showed a decrease in the percentage of mature B cells compare to controls. Knocking down of MT1-MMP in stromal cell reduced the number of adherent hematopoietic cells, but addition of rec. SDF-1 could reverse the phenotype. These results suggested stromal-derived MT1-MMP was functionally important to maintain HSC function in long-term cultures of WT HSCs. Thus, MT1-MMP is a critical modulator of hematopoiesis, as it alters the growth factor output of niche cells. Disclosures:No relevant conflicts of interest to declare.

Chlorella vulgaris Modulates Immunomyelopoietic Activity and Enhances the Resistance of Tumor-Bearing Mice

We studied the effects of Chlorella vulgaris (CV) on the interaction between stromal and hematopoietic stem cells in normal and Ehrlich ascites tumor (EAT)-bearing mice. Long-term bone marrow culture (LTBMC), cytokine production, spleen mononuclear cells (SMC) proliferation (SCP), colony stimulating activity (CSA), and NK cells activity were evaluated. In tumor bearers, reduced capacity of stromal cell layer to support the growth and differentiation of granulocyte-macrophage progenitor cells (CFU-GM), concomitantly to decreased numbers of total nonadherent cells in LTBMC and reduced local production of IL-6 and IL-1α, were observed. Presence of the tumor has not altered the number of stromal adherent cells. CV treatment restored the ability of stromal cells from EAT-bearing mice to produce IL-6 and IL-1α, which was consistent with increased number of nonadherent cells and higher ability to display CFU-GM in vitro. EAT growth increased SCP, serum CSA, and IL-10 production and concurrently depressed NK cell activity and the secretion of IL-2, IFN-γ, and TNF-α. Treatment of tumor-bearing mice with CV augmented CSA, SMC proliferation, NK cell activity, and the production of IL-2, IFN-γ, and TNF-α, whereas IL-10 levels where reduced. Our results suggest that CV modulates immunehematopoietic cell activity and disengages tumor-induced suppression of these responses.

Human blood and marrow side population stem cell and Stro-1 positive bone marrow stromal cell numbers decline with age, with an increase in quality of surviving stem cells: Correlation with cytokines

Hematological deficiencies increase with aging leading to anemias, reduced hematopoietic stress responses and myelodysplasias. This study tested the hypothesis that side population hematopoietic stem cells (SP-HSC) would decrease with aging, correlating with IGF-1 and IL-6 levels and increases in bone marrow fat. Marrow was obtained from the femoral head and trochanteric region of the femur at surgery for total hip replacement ( N = 100). Whole trabecular marrow samples were ground in a sterile mortar and pestle and cellularity and fat content determined. Marrow and blood mononuclear cells were stained with Hoechst dye and the SP-HSC profiles acquired. Marrow stromal cells (MSC) were enumerated flow cytometrically employing the Stro-1 antibody, and clonally in the colony forming unit fibroblast (CFU-F) assay. Plasma levels of IGF-1 (ng/ml) and IL-6 (pg/ml) were measured by ELISA. SP-HSC in blood and bone marrow decreased with age but the quality of the surviving stem cells increased. MSC decreased non-significantly. IGF-1 levels (mean = 30.7, SEM = 2) decreased and IL-6 levels (mean = 4.4, SEM = 1) increased with age as did marrow fat (mean = 1.2 mm fat/g, SEM = 0.04). There were no significant correlations between cytokine levels or fat and SP-HSC numbers. Stem cells appear to be progressively lost with aging and only the highest quality stem cells survive.

Improving bone marrow stromal cell attachment on chitosan/hydroxyapatite scaffolds by an immobilized RGD peptide

Ample cell adhesion to scaffolds is essential for effective bone tissue engineering. Chitosan/hydroxyapatite (CS/HA) scaffolds with channel-shaped and spherically shaped pore morphologies were prepared via in situ compositing hybridization in combination with lyophilization. The sizes of channel-shaped and spherically shaped pores of the CS/HA scaffolds were 150–650 µm and 3–15 µm, respectively. The RGD peptide (Arg-Gly-Asp) was bound to the surface of CS/HA scaffolds via physical adsorption. More than 63% of RGD present in a PBS solution spontaneously adsorbed onto CS/HA scaffolds. High numbers of viable bone marrow stromal cells (BMSCs) were observed by confocal and fluorescence microscopy for cells cultured on CS/HA scaffolds with and without RGD for 3 days. BMSCs on CS/HA scaffolds with RGD (RGD-CS/HA) were incubated for 4 h under standard culture conditions, and the degree of cell adhesion was calculated. Cell adhesion to RGD-CS/HA scaffolds with different RGD concentrations was 71.6% and 80.7%, respectively. This was 30.9% and 47.5% higher than adhesion to the CS/HA scaffold without RGD, respectively. BMSCs cultured on the scaffolds for 14 days with osteogenic supplements expressed 103% higher alkaline phosphatase on the RGD-CS/HA scaffold (0.001 97 ± 0.000 31 U/L/ng), than on the unmodified scaffold (0.000 97 ± 0.000 25 U/L/ng) (p < 0.01), indicating that a RGD peptide significantly promotes osteogenic differentiation of BMSCs on CS/HA scaffolds. The results of this study indicate that RGD-CS/HA scaffolds promote initial cell adhesion, spread and differentiation toward an osteogenic phenotype.

Stromal Macrophage Expressing CD204 is Associated with Tumor Aggressiveness in Lung Adenocarcinoma

Tumor tissue is composed of variable numbers of cancer cells and stromal cells, and tumor-associated macrophages are recruited into cancer-induced stroma and produce a specific microenvironment. Alternatively, activated macrophages (M2 phenotype) are known to be related to tumor progression and outcome, and CD204 has been reported to be expressed in M2 macrophages in some tumors. To investigate whether CD204-positive macrophages reflect tumor aggressiveness in adenocarcinoma of the lung, we investigated the relationships between the numbers of CD204-positive stromal macrophages and both clinicopathological features and outcome in 170 consecutive resected cases. We also examined the relationships between the numbers of CD204-positive macrophages and the expression levels of cytokines involved in the migration and differentiation of M2 macrophages. The numbers of CD204-positive macrophages were significantly correlated with several prognostic factors. The log-rank test showed a significant association between the numbers of CD204-positive macrophages and a poor outcome (p = 0.0073), whereas the numbers of macrophages expressing CD68, a pan-macrophage/monocyte marker, were of marginal prognostic significance (p = 0.0789). We evaluated associations between the levels of expression of the cytokines IL-6, IL-10, IL-12a, IL-12b, M-colony-stimulating factor, IFN-gamma-., and monocyte chemoattractant protein-1 in cancer tissue and the numbers of CD204-positive macrophages. The expression levels of IL-10 and monocyte chemoattractant protein-1, which are involved in differentiation, accumulation, and migration of M2 macrophages, were significantly correlated with the numbers of CD204-positive macrophages (p = 0.031 and p = 0.031, respectively). These findings demonstrated that CD204-positive macrophages clearly reflect the tumor-promoting phenotype of tumor-associated macrophages in lung adenocarcinoma.

CD90/THY1 is overexpressed in prostate cancer-associated fibroblasts and could serve as a cancer biomarker

A by-product in the processing of prostate tissue for cell sorting by collagenase digestion is the media supernatant that remains after the cells are harvested. These supernatants contain proteins made by the cells within the tissue. Quantitative proteomic analysis of N-glycosylated proteins detected an increased amount of CD90/THY1 in cancer supernatants compared with non-cancer supernatants. Immunohistochemistry showed that in all carcinomas, regardless of Gleason grade, a layer of CD90-positive stromal fibroblastic cells, ∼5 to 10 cells deep, was localized to tumor glands. In contrast, a no more than 1-cell wide girth of CD90-positive stromal cells was found around benign glands. The increased number of CD90-positive stromal cells in cancer correlated with overexpression of CD90 mRNA detected by gene expression analysis of stromal cells obtained by laser-capture microdissection. There is increasing evidence that cancer-associated stroma has a function in both tumor progression and carcinogenesis. Most experiments to identify cancer biomarkers have focused on the cancer cells. CD90, being a marker for prostate cancer-associated stroma, might be a potential biomarker for this cancer. A non-invasive test could be provided by a urine test. Proteomic analysis of urine from patients with prostate cancer identified CD90; conversely, CD90 was not detected in the urine of post-prostatectomy patients. Furthermore, this urinary CD90 protein was a variant CD90 protein not known to be expressed by such cells as lymphocytes that express CD90. These CD90 results were obtained from ∼90 cases consisting of proteomic analysis of tissue and urine, immunohistochemistry, western blot analysis of tissue media, flow cytometry of cells from digested tissue, and reverse transcriptase polymerase chain reaction analysis of isolated stromal cells.

T-cell recruitment and Th1 polarization in adipose tissue during diet-induced obesity in C57BL/6 mice.

The role of adaptive immunity in obesity-associated adipose tissue (AT) inflammation and insulin resistance (IR) is controversial. We employed flow cytometry and quantitative PCR to assess T-cell recruitment and activation in epididymal AT (eAT) of C57BL/6 mice during 4-22 weeks of a high-fat diet (HFD (60% energy)). By week 6, eAT mass and stromal vascular cell (SVC) number increased threefold in mice fed HFD, coincident with onset of IR. We observed no increase in the proportion of CD3(+) SVCs or in gene expression of CD3, interferon-γ (IFN-γ), or regulated upon activation, normal T-cell expressed and secreted (RANTES) during the first 16 weeks of HFD. In contrast, CD11c(+) macrophages (MΦ) were enriched sixfold by week 8 (P < 0.01). SVC enrichment for T cells (predominantly CD4(+) and CD8(+)) and elevated IFN-γ and RANTES gene expression were detected by 20-22 weeks of HFD (P < 0.01), coincident with the resolution of eAT remodeling. HFD-induced T-cell priming earlier in the obesity time course is suggested by (i) elevated (fivefold) interleukin-12 (IL-12)p40 gene expression in eAT by week 12 (P ≤ 0.01) and (ii) greater IFN-γ secretion from phorbol myristate acetate (PMA)/ionophore-stimulated eAT explants at week 6 (onefold, P = 0.08) and week 12 (fivefold, P < 0.001). In conclusion, T-cell enrichment and IFN-γ gene induction occur subsequent to AT macrophage (ATMΦ) recruitment, onset of IR and resolution of eAT remodeling. However, enhanced priming for IFN-γ production suggests the contribution of CD4(+) and/or CD8(+) effectors to cell-mediated immune responses promoting HFD-induced AT inflammation and IR.

Aberrant expression of the pluripotency marker SOX-2 in endometriosis

Expression of the pluripotency factors SOX-2, OCT-4, KLF-4, and NANOG was analyzed by quantitative real-time polymerase chain reaction, immunohistochemistry, and immunofluorescence microscopy in the endometrium, myometrium, and endometriotic tissue of 36 patients. Aberrant expression of SOX-2 may indicate a stem cell origin of endometriosis, whereas the presence of all progenitor markers in endometrial tissue marks the endometrium as a potential source for induced pluripotent stem cell generation.

Human Thymus Mesenchymal Stromal Cells Augment Force Production in Self-Organized Cardiac Tissue

Mesenchymal stromal cells have been recently isolated from thymus gland tissue discarded after surgical procedures. The role of this novel cell type in heart regeneration has yet to be defined. The purpose of this study was to evaluate the therapeutic potential of human thymus-derived mesenchymal stromal cells using self-organized cardiac tissue as an in vitro platform for quantitative assessment. Mesenchymal stromal cells were isolated from discarded thymus tissue from neonates undergoing heart surgery and were incubated in differentiation media to demonstrate multipotency. Neonatal rat cardiomyocytes self-organized into cardiac tissue fibers in a custom culture dish either alone or in combination with varying numbers of mesenchymal stromal cells. A transducer measured force generated by spontaneously contracting self-organized cardiac tissue fibers. Work and power outputs were calculated from force tracings. Immunofluorescence was performed to determine the fate of the thymus-derived mesenchymal stromal cells. Mesenchymal stromal cells were successfully isolated from discarded thymus tissue. After incubation in differentiation media, mesenchymal stromal cells attained the expected phenotypes. Although mesenchymal stromal cells did not differentiate into mature cardiomyocytes, addition of these cells increased the rate of fiber formation, force production, and work and power outputs. Self-organized cardiac tissue containing mesenchymal stromal cells acquired a defined microscopic architecture. Discarded thymus tissue contains mesenchymal stromal cells, which can augment force production and work and power outputs of self-organized cardiac tissue fibers by several-fold. These findings indicate the potential utility of mesenchymal stromal cells in treating heart failure.

Growth rate of the cell populations of the rat sublingual gland during the early postnatal period

The development of the rat sublingual gland during the first month of postnatal life was analyzed by morphometry. The absolute number of cells in the various morphological glandular compartments - mixed acini with serous demilunes, intercalated ducts, striated ducts and stroma - was determined by the Aherne II morphometric method for particle counting. The data of fresh glandular volume and the number of cells were analyzed by linear, exponential and parabolic regression, with the best fits being obtained with the linear equation. Based on these equations, the growth rate of glandular volume and of each cell population was calculated. Glandular volume increased about 12-fold during the period from 2 to 30 days of postnatal life, corresponding to a rate of 1.34 mm3/day. This volumetric growth of the gland was mainly due to significant 16-, 10-, 4-, 7- and 8-fold increases in the absolute number of mucous acinar, serous demilune, intercalated duct, striated duct and stromal cells, corresponding to a growth rate of 301 x 103, 228 x 103, 19 x 103, 54 x 103 and 247 x 103 cells/day, respectively. Based on the present results, we conclude that the mucous and serous cell populations of the mixed acini grew at a rate close to that of stromal cells, but considerably higher than that obtained for the intercalated duct and striated duct populations, with the lowest growth rate being observed for the ntercalated duct cell population.

Smad4 loss is associated with fewer S100A8-positive monocytes in colorectal tumors and attenuated response to S100A8 in colorectal and pancreatic cancer cells

S100A8 and its dimerization partner S100A9 are emerging as important chemokines in cancer. We previously reported that Smad4-negative pancreatic tumors contain fewer stromal S100A8-positive monocytes than their Smad4-positive counterparts. Here, we studied S100A8/A9-expressing cells in colorectal tumors relating their presence to clinicopathological parameters and Smad4 status. Two-dimensional gel electrophoresis (n = 12) revealed variation in the levels of S100A8 protein in colorectal cancer tumors, whereas immunohistochemical analysis (n = 313) showed variation in the numbers of stromal S100A8-positive and S100A9-positive cells. Loss of Smad4 expression was observed in 42/304 (14%) colorectal tumors and was associated with reduced numbers of S100A8-positive (P = 0.03) but not S100A9-positive stromal cells (P = 0.26). High S100A9 cell counts were associated with large tumor sizes (P = 0.0006) and poor differentiation grade (P = 0.036). However, neither S100A8 nor S100A9 cell counts predicted poor survival, except for patients with Smad4-negative tumors (P = 0.02). To address the impact of environmental S100A8/A9 chemokines on tumor cells, we examined the effects of exogenously added S100A8 and S100A9 proteins on cellular migration and proliferation of colorectal and pancreatic cancer cells. S100A8 and S100A9 enhanced migration and proliferation in Smad4-positive and Smad4-negative cancer cells. However, transient depletion of Smad4 resulted in loss of responsiveness to exogenous S100A8, but not S100A9. S100A8 and S100A9 activated Smad4 signaling as evidenced by phosphorylation of Smad2/3; blockade of the receptor for the advanced glycation end products inhibited this response. In conclusion, Smad4 loss alters the tumor's interaction with stromal myeloid cells and the tumor cells' response to the stromal chemokine, S100A8.

Corneal Involvement in Graves' Orbitopathy: An In Vivo Confocal Study

To study the clinical involvement of the ocular surface and the in vivo morphology of corneal cells and nerves, in patients affected by active and inactive Graves' orbitopathy (GO). The study included 26 consecutive GO patients and 20 age- and sex-matched healthy control subjects. GO was diagnosed on the basis of the criteria of the European Group on Graves' Orbitopathy, and disease activity was evaluated by the Clinical Activity Score (CAS). Each participant underwent a full eye examination, including an evaluation of symptoms (Ocular Surface Disease Index score), tear break-up time, fluorescein and lissamine green staining, corneal apex sensitivity, and Schirmer's test. The corneal apex was examined by means of confocal microscopy to investigate the number and morphology of epithelial and stromal corneal cells and subbasal nerves. Eleven (43%) of the 26 patients had active GO. One-way ANOVA with the least-significant difference (LSD) post hoc test revealed statistically significant differences between patients and controls in all the evaluated parameters, except corneal sensitivity and nerve reflectivity. Among the GO patients, the only significant difference observed in active compared with inactive disease was in the number of hyperreflective (activated) keratocytes (P<0.001, LSD). Corneal sensitivity correlated inversely with proptosis (P<0.001, Spearman's test). GO patients show clinical and confocal corneal alterations and signs and symptoms partially related to dry eye disease. The ocular surface inflammation in GO seems to be due to both the dry eye and the autoimmune orbitopathy.

Thrombospondin-2 regulates matrix mineralization in MC3T3-E1 pre-osteoblasts

The matricellular protein thrombospondin-2 (TSP2) has context-dependent effects on osteoblast lineage proliferation and differentiation. Mice lacking TSP2 display increased endocortical bone thickness, which is associated with increased marrow stromal cell (MSC) number and in vitro proliferation. TSP2-null MSC also exhibit delayed osteoblastogenesis and enhanced adipogenesis compared to cells harvested from wild type mice. The goal of the present work was to more precisely characterize the contribution that TSP2 makes to the maturation of osteoblast-derived extracellular matrix (ECM) using a highly characterized pre-osteoblast cell line. Specifically, we asked whether TSP2 influences mineralization indirectly through its known effects on proliferation, or whether TSP2 directly promotes osteoblast differentiation. To pursue these questions, we used RNA-interference (RNAi) to inhibit TSP2 gene expression in MC3T3-E1 pre-osteoblasts. Introduction of siRNA oligonucleotides resulted in reduced TSP2 mRNA expression as early as 24 h post-transfection, and TSP2 mRNA levels remained low for 10 days. Similarly, TSP2 protein levels in both conditioned medium and the cell-matrix layer were reduced at 24 h post-transfection and remained reduced for 7 days. At day 21, mineralization was significantly reduced in cells transfected with TSP2 siRNA when compared to cells treated with scrambled siRNA. This decrease in mineralization occurred without a concomitant change in cell number. Twenty-four hours after transfection, runx2 gene expression was transiently enhanced in TSP2 siRNA-treated cultures. Between 6 and 14 days post-transfection, runx2, osterix, alkaline phosphatase, type I collagen, osteocalcin and bone sialoprotein all displayed moderate increases in gene expression with TSP2 RNAi. As well, soluble osteocalcin levels were markedly higher in the conditioned medium of cells treated with TSP2 siRNA than in control siRNA-treated cells. Increased soluble osteocalcin occurred without a concomitant change in the levels of osteocalcin in the cell-ECM layer. TSP2 reduction also elicited a transient change in the distribution of collagen between the acid soluble cell-ECM protein fraction and the insoluble matrix. Together, our data suggest that TSP2 may promote mineralization, by facilitating proper organization of the osteoblast-derived ECM.

Umbilical Cord Wharton's Jelly: A New Potential Cell Source of Mesenchymal Stromal Cells for Bone Tissue Engineering

Although bone marrow-derived mesenchymal stromal cells (BMSCs) are a main cell source for tissue-engineered bone (TEB), the clinical use of BMSCs is restricted due to the invasive bone marrow aspiration procedure and the decline in available number of mesenchymal stromal cells (MSCs) and differentiation potential with increasing age. Umbilical cord-derived MSCs (UCMSCs) are likely to be a promising alternative cell source for TEB due to their higher availability and potential to proliferate and differentiate. To assess this possibility, we studied bone morphogenetic protein 2 (BMP2)-induced osteogenic differentiation and activation of signaling pathways in UCMSCs and BMSCs. UCMSCs showed a phenotype and differentiation potential similar to that of BMSCs. After 14 days of BMP2 treatment, the overall expression of several osteogenic-specific phenotypes (type I collagen, osteopontin, and osteocalcin) was similar for UCMSCs and BMSCs. The signaling pathway by which BMP2 induced differentiation of both cell types involved the membrane receptor-initiated signals including SMADs, P38, and extracellular regulated kinase. The similar characteristics of BMP2-induced osteogenic differentiation of UCMSCs and BMSCs in vitro would support the use of UCMSCs in TEB.