Enhanced anti-inflammatory effects of mesenchymal stromal cells mediated by the transient ectopic expression of CXCR4 and IL10.

BACKGROUND: Mesenchymal stromal cells (MSCs) constitute one of the cell types most frequently used in cell therapy. Although several studies have shown the efficacy of these cells to modulate inflammation in different animal models, the results obtained in human clinical trials have been more modest. Here, we aimed at improving the therapeutic properties of MSCs by inducing a transient expression of two molecules that could enhance two different properties of these cells. With the purpose of improving MSC migration towards inflamed sites, we induced a transient expression of the C-X-C chemokine receptor type 4 (CXCR4). Additionally, to augment the anti-inflammatory properties of MSCs, a transient expression of the anti-inflammatory cytokine, interleukin 10 (IL10), was also induced. METHODS: Human adipose tissue-derived MSCs were transfected with messenger RNAs carrying the codon-optimized versions of CXCR4 and/or IL10. mRNA-transfected MSCs were then studied, first to evaluate whether the characteristic phenotype of MSCs was modified. Additionally, in vitro and also in vivo studies in an LPS-induced inflamed pad model were conducted to evaluate the impact associated to the transient expression of CXCR4 and/or IL10 in MSCs. RESULTS: Transfection of MSCs with CXCR4 and/or IL10 mRNAs induced a transient expression of these molecules without modifying the characteristic phenotype of MSCs. In vitro studies then revealed that the ectopic expression of CXCR4 significantly enhanced the migration of MSCs towards SDF-1, while an increased immunosuppression was associated with the ectopic expression of IL10. Finally, in vivo experiments showed that the co-expression of CXCR4 and IL10 increased the homing of MSCs into inflamed pads and induced an enhanced anti-inflammatory effect, compared to wild-type MSCs. CONCLUSIONS: Our results demonstrate that the transient co-expression of CXCR4 and IL10 enhances the therapeutic potential of MSCs in a local inflammation mouse model, suggesting that these mRNA-modified cells may constitute a new step in the development of more efficient cell therapies for the treatment of inflammatory diseases.

Medium- and long-term functional behavior evaluations in an experimental focal ischemic stroke mouse model.

Cerebrovascular accident (CVA) is one of the leading causes of death and disability worldwide, as well as a major financial burden for health care systems. CVA rodent models provide experimental support to determine possible in vivo therapies to reduce brain injury and consequent sequelae. This study analyzed nociceptive, motor, cognitive and mood functions in mice submitted to distal middle cerebral artery (DMCA) occlusion. Male C57BL mice (n = 8) were randomly allocated to control or DMCA groups. Motor function was evaluated with the tests: grip force, rotarod and open field; and nociceptive threshold with von Frey and hot plate assessments. Cognitive function was evaluated with the inhibitory avoidance test, and mood with the tail suspension test. Evaluations were conducted on the seventh- and twenty-eighth-day post DMCA occlusion to assess medium- and long-term effects of the injury, respectively. DMCA occlusion significantly decreases muscle strength and spontaneous locomotion (p < 0.05) both medium- and long term; as well as increases immobility in the tail-suspension test (p < 0.05), suggesting a depressive-type behavior. However, DMCA occlusion did not affect nociceptive threshold nor cognitive functions (p > 0.05). These results suggest that, medium- and long-term effects of DMCA occlusion include motor function impairments, but no sensory dysfunction. Additionally, the injury affected mood but did not hinder cognitive function.

Histopathology of motor cortex in an experimental focal ischemic stroke in mouse model.

Experimental ischemia results in cortical brain lesion followed by ischemic stroke. In this study, focal cerebral ischemia was induced in mice by occlusion of the middle cerebral artery. We studied cortical layers I, II/III, V and VI in the caudal forelimb area (CFA) and medial agranular cortex (AGm) from control and C57BL/6 mice induced with ischemic stroke. Based on our analysis of CFA and AGm motor cortex, significant differences were observed in the numbers of neurons, astrocytes and microglia in the superficial II/III and deep V cortical layers. Cellular changes were more prominent in layer V of the CFA with nuclear pyknosis, chromatin fragmentation, necrosis and degeneration, as well as, morphological evidence of apoptosis, mainly in neurons. As result, the CFA was more severely impaired than the AGm in this focal cerebral ischemic model, as evidenced by the proliferation of astrocytes, potentially resulting in neuroinflammation by microglia-like cells.

Fibroblast growth factor 2 promotes the self-renewal of bipotent glial smooth muscle neural crest progenitors.

The neural crest (NC) is an attractive system for investigating the mechanisms underlying cell lineage diversification in higher vertebrates. The NC contains a mixed population of already defined precursors and multipotent cells that can give rise to a great variety of cell types, including glial cells and neurons of the peripheral nervous system, melanocytes, and smooth muscle cells (SMCs). Microenvironmental factors, such as the fibroblast growth factor 2 (FGF2), found along migratory paths and in target tissues, strongly influence the fate of multipotent NC precursors. We have previously demonstrated that the FGF2 promotes the differentiation of NC cells to glial phenotypes, while the epidermal growth factor induces NC differentiation to neurons and melanocytes. In the present study, we used mass cultures and single-cell culture assays to demonstrate that FGF2 influences NC cell differentiation and increases the proportion of multipotent progenitors. Furthermore, we demonstrate for the first time that avian tripotent glial, melanocyte and smooth muscle NC progenitors, as well as bipotent melanocyte and smooth muscle NC progenitors, are capable of self-renewal. FGF2 significantly stimulated the self-renewal of bipotent progenitor cells with glial cells and SMC potentials. These cells propagated for many generations and behaved as stem cells. These results suggest an important role of FGF2 in maintaining the stemness of avian NC cells.

Human placenta-derived mesenchymal stem cells acquire neural phenotype under the appropriate niche conditions.

Mesenchymal stem cells (MSCs) are multipotent stem cells with clinical interest. It has been reported that MSCs can be isolated from the human term placenta. We investigated the ability of human placenta-derived MSCs to differentiate into a neural phenotype in coculture assays with astrocytes obtained from neonatal rats. Placenta-derived MSCs were cocultured on a confluent monolayer of astrocytes obtained from the rat cerebellum to evaluate the differences in morphology. The extracellular matrix (ECM) produced by astrocytes as well as the growth factors produced by the astrocyte-conditioned medium were evaluated. The expression of the neural markers glial fibrillate acid protein (GFAP) and Nestin was studied in MSCs by immunocytochemistry. MSCs were able to respond to the astrocyte niche in coculture assays. They expressed the neural markers GFAP, Nestin, or ß-Tubulin III, followed by an outgrowth of cell processes. The ECM from astrocytes was not effective in inducing the neural phenotype in MSCs, although the expression of ß-Tubulin III was observed. When MSCs were cocultured with cerebellar astrocytes from newborn rats, a neural phenotype was achieved. This was determined by immunocytochemistry to GFAP, Nestin, or ß-Tubulin III and by morphological changes. It was achieved without the addition of exogenous differentiation factors. This demonstrates that placenta-derived MSCs may be able to differentiate into neural cell types when in direct contact with a neural environment.

Uncaria tomentosa stimulates the proliferation of myeloid progenitor cells.

ETHNOPHARMACOLOGICAL RELEVANCE: The Asháninkas, indigenous people of Peru, use cat's claw (Uncaria tomentosa) to restore health. Uncaria tomentosa has antioxidant activity and works as an agent to repair DNA damage. It causes different effects on cell proliferation depending on the cell type involved; specifically, it can stimulate the proliferation of myeloid progenitors and cause apoptosis of neoplastic cells. Neutropenia is the most common collateral effect of chemotherapy. For patients undergoing cancer treatment, the administration of a drug that stimulates the proliferation of healthy hematopoietic tissue cells is very desirable. It is important to assess the acute effects of Uncaria tomentosa on granulocyte-macrophage colony-forming cells (CFU-GM) and in the recovery of neutrophils after chemotherapy-induced neutropenia, by establishing the correlation with filgrastim (rhG-CSF) treatment to evaluate its possible use in clinical oncology. MATERIALS AND METHODS: The in vivo assay was performed in ifosfamide-treated mice receiving oral doses of 5 and 15 mg of Uncaria tomentosa and intraperitoneal doses of 3 and 9 µg of filgrastim, respectively, for four days. Colony-forming cell (CFC) assays were performed with human hematopoietic stem/precursor cells (hHSPCs) obtained from umbilical cord blood (UCB). RESULTS: Bioassays showed that treatment with Uncaria tomentosa significantly increased the neutrophil count, and a potency of 85.2% was calculated in relation to filgrastim at the corresponding doses tested. An in vitro CFC assay showed an increase in CFU-GM size and mixed colonies (CFU-GEMM) size at the final concentrations of 100 and 200 µg extract/mL. CONCLUSIONS: At the tested doses, Uncaria tomentosa had a positive effect on myeloid progenitor number and is promising for use with chemotherapy to minimize the adverse effects of this treatment. These results support the belief of the Asháninkas, who have classified Uncaria tomentosa as a 'powerful plant'.

Impaired astrocytic extracellular matrix distribution under congenital hypothyroidism affects neuronal development in vitro.

Astrocytes clearly play a role in neuronal development. An indirect mechanism of thyroid hormone (T3) in the regulation of neuronal development mediated by astrocytes has been proposed. T3 alters the production and organization of the extracellular matrix (ECM) proteins and proteoglycans, producing a high-quality substrate for neuronal differentiation. The present study investigated the effect of hypothyroidism on the astrocyte production of fibronectin (FN) and laminin (LN) as well as their involvement in neuronal growth and neuritogenesis. Our results demonstrated that the amount of both FN and LN were significantly reduced in cultures of hypothyroid astrocytes from rat cerebellum compared with normal cells. This effect was accompanied by reduced numbers of neurons and neuritogenesis. Similarly, the proportions of neurons and neurons with neurites were reduced in cultures on ECM prepared from hypothyroid astrocytes in comparison with normal cells. The proportion of both normal and hypothyroid neurons is strongly reduced in astrocyte ECM compared with cocultures on astrocyte monolayers, suggesting that extracellular factors other than ECM proteins are involved in this process. Moreover, treatment of hypothyroid astrocytic cultures with T3 restored the area of both FN and LN immunostaining to normal levels and partially reestablished neuronal survival and neuritogenesis. Taken together, our results demonstrated that hypothyroidism involves impairment of the astrocytic microenvironment and affects the production of ECM proteins. Thus, hypothyroidism is implicated in impaired neuronal development.

Epidermal growth factor (EGF) promotes the in vitro differentiation of neural crest cells to neurons and melanocytes.

Proliferation of neural crest (NC) stem cells and their subsequent differentiation into different neural cell types are key early events in the development of the peripheral nervous system. Soluble growth factors present at the sites where NC cells migrate are critical to the development of NC derivatives in each part of the body. In the present study, we further investigate the effect of microenvironmental factors on quail trunk NC development. We show for the first time that EGF induces differentiation of NC to the neuronal and melanocytic phenotypes, while fibroblast growth factor 2 (FGF2) promotes NC differentiation to Schwann cells. In the presence of both EGF and FGF2, the neuronal differentiation predominates. Our results suggest that FGF2 stimulates gliogenesis, while EGF promotes melanogenesis and neurogenesis. The combination of both growth factors stimulates neurogenesis. These findings suggest that these two growth factors may play an important role in the fate decision of NC progenitors and in the development of the peripheral nervous system.

Fibronectin promotes differentiation of neural crest progenitors endowed with smooth muscle cell potential.

The neural crest (NC) is a model system used to investigate multipotency during vertebrate development. Environmental factors control NC cell fate decisions. Despite the well-known influence of extracellular matrix molecules in NC cell migration, the issue of whether they also influence NC cell differentiation has not been addressed at the single cell level. By analyzing mass and clonal cultures of mouse cephalic and quail trunk NC cells, we show for the first time that fibronectin (FN) promotes differentiation into the smooth muscle cell phenotype without affecting differentiation into glia, neurons, and melanocytes. Time course analysis indicated that the FN-induced effect was not related to massive cell death or proliferation of smooth muscle cells. Finally, by comparing clonal cultures of quail trunk NC cells grown on FN and collagen type IV (CLIV), we found that FN strongly increased both NC cell survival and the proportion of unipotent and oligopotent NC progenitors endowed with smooth muscle potential. In contrast, melanocytic progenitors were prominent in clonogenic NC cells grown on CLIV. Taken together, these results show that FN promotes NC cell differentiation along the smooth muscle lineage, and therefore plays an important role in fate decisions of NC progenitor cells.

Is there a role for fibronectin upon true histiocytic lymphoma progression?

Cell interaction with extracellular matrix is a crucial event for various biological processes, including tumor progression. Although not exclusively, these interactions are frequently mediated by bidirectional signaling receptors known as integrins. Using a human histiocytic lymphoma-derived cell line (U-937), we evaluated the effects of ECM proteins and their integrin-type receptors in the regulation of cell attachment, proliferation, migration and survival. Fibronectin induces higher cell attachment in vitro when compared to laminin. Fibronectin also promotes a decrease in cell migration but do not modulate cell proliferation and death. Pre-incubation of U-937 cells with VLA-5 antagonistic peptides inhibited attachment of the cells to fibronectin-coated substrates. In a second vein, we observed that lymph node specimens obtained from diagnosed patient for true histiocytic lymphoma had greater deposition of fibronectin (but not laminin) around malignant clones. These results suggest that fibronectins play a relevant role in the establishment and progression of true histiocytic lymphoma cells.

Thyroid hormone increases astrocytic glutamate uptake and protects astrocytes and neurons against glutamate toxicity.

Thyroid hormone (T(3)) regulates the growth and differentiation of rat cerebellar astrocytes. Previously, we have demonstrated that these effects are due, at least in part, to the increased expression of extracellular matrix molecules and growth factors, such as fibroblast growth factor-2. T(3) also modulates neuronal development in an astrocyte-mediated manner. In the mammalian central nervous system, excitatory neurotransmission is mediated mainly by glutamate. However, excessive stimulation of glutamate receptors can lead to excitotoxicity and cell death. Astrocytic glutamate transporters, GLT-1 and GLAST, play an essential role in the clearance of the neuronal-released glutamate from the extracellular space and are essential for maintaining physiological extracellular glutamate levels in the brain. In the present study, we showed that T(3) significantly increased glutamate uptake by cerebellar astrocytes compared with control cultures. Inhibitors of glutamate uptake, such as L-PDC and DL-TBOA, abolished glutamate uptake on control or T(3)-treated astrocytes. T(3) treatment of astrocytes increased both mRNA levels and protein expression of GLAST and GLT-1, although no significant changes on the distribution of these transporters were observed. The gliotoxic effect of glutamate on cultured cerebellar astrocytes was abolished by T(3) treatment of astrocytes. In addition, the neuronal viability against glutamate challenge was enhanced on T(3)-treated astrocytes, showing a putative neuroprotective effect of T(3). In conclusion, our results showed that T(3) regulates extracellular glutamate levels by modulating the astrocytic glutamate transporters. This represents an important mechanism mediated by T(3) on the improvement of astrocytic microenvironment in order to promote neuronal development and neuroprotection.

Thyroid hormone mediates syndecan expression in rat neonatal cerebellum.

Thyroid hormone (T(3)) plays an essential role in the central nervous system development. Astrocytes mediate many of the T(3) effects in the growth and differentiation of cerebellum. In culture, T(3) induces cerebellar astrocytes to secrete growth factors, mainly FGF(2), and alters the expression and organization of the extracellular matrix (ECM) proteins, laminin, and fibronectin. In addition, T(3)-treated astrocytes promote neuronal differentiation. In this study, we have investigated whether other ECM molecules, such as syndecans, are involved in T(3) action. Thus, we analyzed the expression of syndecans (1-4) by RT-PCR in astrocyte cultures from cerebellum, cortex, and hippocampus of newborn rats. Our results showed that syndecans (1-4) are expressed in astrocytes of cerebellum and cortex, whereas in hippocampus only syndecans 2 and 4 were detected. Semi-quantitative RT-PCR analysis revealed the reduced expression of syndecans 1, 2, and 4, and increased expression of syndecan 3 in hypothyroid cerebellum, when compared to the euthyroid tissue. Furthermore, we observed a reduced expression of syndecans 2 and 3 in T(3)-treated cerebellar astrocytes, when compared to control cultures. This balance of proteoglycans may be involved in T(3) action mediated by FGF(2) signaling, possibly affecting the formation of the trimeric signaling receptor complex composed by syndecan/FGF/FGF-receptor (FGFR), which is essential for FGFR dimerization, activation, and subsequent cell signaling.

Stealth and non-stealth nanocapsules containing camptothecin: in-vitro and in-vivo activity on B16-F10 melanoma.

Camptothecin (CPT) is an alkaloid that displays considerable antitumour activity, but clinical use has been limited by its poor water solubility and the instability of the lactone moiety (active form) in physiological media. We have therefore formulated the drug into nanocarrier systems in an attempt to improve its therapeutic properties. This study evaluates the effect of intraperitoneally administered stealth and non-stealth nanocapsules containing CPT on lung metastatic spread in mice inoculated with B16-F10 melanoma cells, and on the cytotoxic activity against B16-F10 melanoma cells in-vitro. Poly (D,L-lactide) PLA (non-stealth) and methoxy polyethylene glycol-(D,L-lactide) (PLA-PEG) (stealth) nanocapsules (49 and 66.6 kDa) were prepared by interfacial deposition of preformed polymer. CPT, as free drug or as drug-loaded nanocapsules, was administrated at a dose of 0.5 mg kg(-1) at 3-day intervals for 17 days. Free drug and CPT-loaded nanocapsules reduced the number of metastatic nodules by 45.09-91.76% (P < 0.05 vs positive control). However, only CPT-loaded PLA-PEG 49 kD nanocapsules significantly decreased the number of lung metastases when compared with free drug (P < 0.05). The administration of CPT-loaded nanocapsules and free drug did not result in neutropenia at the administered dose. The improved effectiveness of pegylated nanocapsules was attributed to protection of the drug by nanoencapsulation and to reduced uptake of particles by macrophages located in the lymph nodes. This assumption was supported by the in-vitro study, in which both PLA and 49 kDa PLA-PEG nanocapsules containing CPT were more cytotoxic than the free drug against B16-F10 melanoma cells.

Undersulfation of glycosaminoglycans induced by sodium chlorate treatment affects the progression of C6 rat glioma, in-vivo.

The stimulatory input of extracellular matrix (ECM) components has been implicated in the invasive properties of glioma cells. It has been demonstrated that undersulfation of glycosaminoglycans (GAGs) promoted by sodium chlorate (SC) treatment reduces C6 glioma cell proliferation and adhesion to ECM molecules, in-vitro. In the present study, the authors investigated the involvement of GAG undersulfation in glioma cell growth in the brain parenchyma. The in-vitro treatment of C6 cells with SC and subsequent intracerebral inoculation in vehicle containing SC resulted in a reduced proportion of animals bearing glioma and a reduced tumor mass diameter. It also promoted longer animal survival. Intracerebral inoculation of SC-treated C6 cells in vehicle without SC or the SC treatment after intracerebral implantation of untreated C6 cells did not result in any reduction of tumor growth. Alterations in clinical, hematological and behavioral parameters in the open field were observed near the point of death when tumors presented a greater size. The results suggest an important role of GAGs in glioma growth which possibly affects cell proliferation and/or interactions with the normal tissue environment.

Evaluation of antimetastatic activity and systemic toxicity of camptothecin-loaded microspheres in mice injected with B16-F10 melanoma cells.

PURPOSE: The aim of this work was to evaluate the pulmonary antimetastatic activity and the systemic toxicity of camptothecin-loaded microspheres. METHODS: PCL microspheres containing camptothecin (CPT) were prepared by the emulsion solvent/evaporation method and characterized according to their encapsulation efficiency, particle size, morphology, and drug release. The ability of CPT to inhibit the lung metastasis was verified using an experimental mouse model intravenously injected with metastatic B16- F10 melanoma cells. The microspheres and the free drug were given intraperitoneally at a dose of 7 mg/kg at intervals of three or five days for 24 days. The systemic toxicity of CPT was evaluated by weight measurements, survival and hemograms of the animals. RESULTS: The encapsulation efficiency was nearly 80%. The drug release was complete after 72 hours, but the burst effect increased from 7% to 35% with the increase in CPT content in the particles. It was observed during the in vivo essays that all groups treated with CPT had a decrease of nearly 70% in the number of lung metastases. However, systemic toxicity was verified in animals that received the free drug. CONCLUSION: Camptothecin-loaded microspheres demonstrated similar therapeutic efficacy when compared to those of the free drug, but the toxicity was significantly reduced.

Thrombospondin in protein malnutrition induced hypoplasia

OBJETIVO: O objetivo do presente estudo foi verificar a concentração de trombospondina da matriz extracelular da medula óssea em camundongos após indução de hipoplasia por desnutrição protéica. MÉTODOS: Camundongos machos Swiss foram submetidos à desnutrição protéica com uma dieta contendo 4,0% de caseína até que perdessem 20,0% do peso original, enquanto o grupo-controle foi mantido com uma dieta contendo 14,0% de caseína por 15 dias. A medula óssea dos dois grupos foi então aspirada e extraída com tampão fosfato. A matriz extracelular foi analisada por SDS-PAGE 7,5% e a concentração de trombospondina foi quantificada por Enhanced Chemiluminescence Light Western blotting, com luminescência química avançada. RESULTADOS: A quantidade de trombospondina foi 30% superior nas amostras obtidas de animais desnutridos em relação às amostras do grupo-controle. CONCLUSÃO: Este estudo sugere que a concentração de trombospondina está aumentada na hipoplasia induzida por desnutrição protéica, provavelmente por alterar o microambiente da medula óssea.

Glycosaminoglycans modulate C6 glioma cell adhesion to extracellular matrix components and alter cell proliferation and cell migration.

BACKGROUND: Adhesion to extracellular matrix (ECM) components has been implicated in the proliferative and invasive properties of tumor cells. We investigated the ability of C6 glioma cells to attach to ECM components in vitro and described the regulatory role of glycosaminoglycans (GAGs) on their adhesion to the substrate, proliferation and migration. RESULTS: ECM proteins (type IV collagen, laminin and fibronectin) stimulate rat C6 glioma cell line adhesion in vitro, in a dose-dependent manner. The higher adhesion values were achieved with type IV collagen. Exogenous heparin or chondroitin sulfate impaired, in a dose-dependent manner the attachment of C6 glioma cell line to laminin and fibronectin, but not to type IV collagen. Dextran sulfate did not affect C6 adhesion to any ECM protein analyzed, indicating a specific role of GAGs in mediating glioma adhesion to laminin and fibronectin. GAGs and dextran sulfate did not induce C6 glioma detachment from any tested substrate suggesting specific effect in the initial step of cell adhesion. Furthermore, heparin and chondroitin sulfate impaired C6 cells proliferation on fibronectin, but not on type IV collagen or laminin. In contrast, both GAGs stimulate the glioma migration on laminin without effect on type IV collagen or fibronectin. CONCLUSION: The results suggest that GAGs and proteoglycans regulate glioma cell adhesion to ECM proteins in specific manner leading to cell proliferation or cell migration, according to the ECM composition, thus modulating tumor cell properties.

Enhancement of blood-tumor barrier permeability by Sar-[D-Phe8]des-Arg9BK, a metabolically resistant bradykinin B1 agonist, in a rat C6 glioma model.

BACKGROUND: While it is well known that bradykinin B2 agonists increase plasma protein extravasation (PPE) in brain tumors, the bradykinin B1 agonists tested thus far are unable to produce this effect. Here we examine the effect of the selective B1 agonist bradykinin (BK) Sar-[D-Phe8]des-Arg9BK (SAR), a compound resistant to enzymatic degradation with prolonged activity on PPE in the blood circulation in the C6 rat glioma model. RESULTS: SAR administration significantly enhanced PPE in C6 rat brain glioma compared to saline or BK (p < 0.01). Pre-administration of the bradykinin B1 antagonist [Leu8]-des-Arg (100 nmol/Kg) blocked the SAR-induced PPE in the tumor area. CONCLUSIONS: Our data suggest that the B1 receptor modulates PPE in the blood tumor barrier of C6 glioma. A possible role for the use of SAR in the chemotherapy of gliomas deserves further study.

The effects of sub-chronic exposure of Wistar rats to the herbicide Glyphosate-Biocarb.

The object of this study was to analyze the hepatic effects of the herbicide Glyphosate-Biocarb (as commercialized in Brazil) in Wistar rats. Animals were treated orally with water or 4.87, 48.7, or 487 mg/kg of glyphosate each 2 days, during 75 days. Sub-chronic treatment of animals starting from the lowest dose of glyphosate induced the leakage of hepatic intracellular enzymes, alanine aminotransferase (ALT) and aspartate aminotransferase (AST), suggesting irreversible damage in hepatocytes. We observed the increase of Kupffer cells in hepatic sinusoid of glyphosate-treated animals. This was followed by large deposition of reticulin fibers, composed mainly of collagen type III. We may conclude that Glyphosate-Biocarb may induce hepatic histological changes as well as AST and ALT leaking from liver to serum in experimental models.

Interaction of leukemic cells with proteins of the extracellular matrix / Interações de células leucêmicas com proteínas da matriz extracelular

The interaction of neoplastic cells with basement membrane molecules is the first step for the dissemination of tumor cells in vivo. Leukemic cells have a great ability to spread in the host, since cells are released from the bone marrow to the circulation. In this study we analysed whether CEM, U937, K562 and HL-60 cells were able to attach to different concentrations of laminin and/or fibronectin and/or type IV collagen. Attachment to type IV collagen was low, but it increased with the addition of laminin and occurred in all four leukemic cell lines. On the other hand, attachment to fibronectin was higher, but it decreased with the addition of laminin in the assays using U937 and HL-60 cells. The combination of type IV collagen and fibronectin was a good substratum for cellular attachment. However, the addition of laminin to this substratum impaired its attachment activity in U937, HL-60 and K562. These data suggest that laminin may control cellular attachment to the extracellular matrix during leukemic dissemination in hosts in different ways.