Arginine metabolic pathways involved in the modulation of tumor-induced angiogenesis by macrophages.

Neovascularization, an essential step for tumor progression and metastasis development, can be modulated by the presence of macrophages (Mps) in the tumor microenvironment. The ability of Mps to regulate the angiogenicity of the LMM3 tumor cell line was studied. Peritoneal Mps from LMM3 tumor-bearing mice (TMps) potentiate in vivo LMM3 angiogenicity. These results were confirmed by CD31 immunoblotting assays. The activity of TMps depended on nitric oxide synthase (NOS) and arginase (A) activity. By immunoblotting we evidenced that AI and AII isoforms were up-regulated in TMps while the inducible and neuronal NOS isoforms were highly expressed in normal Mps. TMps might positively modulate tumor growth by stimulating angiogenic cascade mainly through polyamine synthesis.

Nitric oxide synthase-cyclooxygenase interactions are involved in tumor cell angiogenesis and migration.

Nitric oxide (NO), produced by distinct nitric oxide synthase (NOS) isoforms, and prostaglandins generated by expression of cyclooxygenases are important mediators in tumor progression. Previous studies have shown that NO can influence the formation of prostaglandin E2 (PGE2). We provide evidence that NO, derived from iNOS and eNOS activity in LMM3 murine mammary adenocarcinoma cell line, is involved in tumor angiogenesis and in tumor cell migration. LMM3 cells that also stimulate their neovascularization activity and migration liberate high basal amounts of PGE2. There is large amount of evidence that postulates positive regulatory interactions between NOS and cyclooxygenase (COX) isoforms. We here show that, in the LMM3 cell line, while PGE2 exerts a positive modulation on NOS activity, NO closes the loop with a negative feed back on COX activity. We also provide evidence of a positive regulatory effect of protein tyrosine kinases on NOS as well as on COX enzymatic functions affecting tumor induced angiogenesis and cell migration.

Parkinson's disease is associated with oxidative stress: comparison of peripheral antioxidant profiles in living Parkinson's, Alzheimer's and vascular dementia patients.

Antioxidant profiles in Parkinson's disease (PD; n = 15), dementias of Alzheimer's type (DAT; 18) and Vascular (VD; 15), and control subjects (C; 14) were studied. Cu-Zn superoxide dismutase (SOD), catalase (CAT), glutathione system (GLU) and thiobarbituric acid reactive substances (TBARS) were measured in erythrocytes; antioxidant capacity (TRAP) in plasma. Biochemical variables were analyzed simultaneously using multi-variate and non-parametric methods. Clinical diagnostic resulted associated with the main source of variability in antioxidant variables (Kruskal-Wallis: H = 32.58, p = 0.000001). Comparison of PD and C resulted highly significant (z = 4.47, p = 0.000047), demonstrating an association between oxidative stress and PD. SOD and TBARS were significantly higher in pathological groups against C (p = 0.0000001, p = 0.051); TRAP resulted lower (p = 0.00015). Discriminant functions constructed using biochemical variables separated pathological groups (93% success) from C, and DAT (88.9%) from VD (73.3%); but not PD from DAT or VD. Antioxidant profiles of PD patients showed characteristics overlapping with DAT (60%) and with VD (40%), suggesting biochemical similarities between them.

[Olfactory mucosa: a continuous source of neurons]. / La mucosa olfatoria: una fuente permanente de neuronas.

Experimental transplantation of embryonic nervous cells in the central nervous system demonstrates that these precursor cells can be used to repair damaged cells in neurodegenerative diseases. However, the use of cells from embryos is still controversial and alternative ethically accepted sources are needed to overcome the inherent problems. Several sources have been proposed such as bone marrow cells, olfactory bulb cells and astrocytes. We suggest the use of neuronal precursor cells from the nasal olfactory mucosa as an alternative source for transplantation therapy, since these peripheric cells exhibit stem cell characteristics.

La mucosa olfatoria: una fuente permanente de neuronas. / [Olfactory mucosa: a continuous source of neurons]

Experimental transplantation of embryonic nervous cells in the central nervous system demonstrates that these precursor cells can be used to repair damaged cells in neurodegenerative diseases. However, the use of cells from embryos is still controversial and alternative ethically accepted sources are needed to overcome the inherent problems. Several sources have been proposed such as bone marrow cells, olfactory bulb cells and astrocytes. We suggest the use of neuronal precursor cells from the nasal olfactory mucosa as an alternative source for transplantation therapy, since these peripheric cells exhibit stem cell characteristics.

Anti-third party CD8+ CTLs as potent veto cells: coexpression of CD8 and FasL is a prerequisite.

Several bone marrow cells and lymphocyte subpopulations, known as "veto cells," were shown to induce transplantation tolerance across major histocompatibility antigens. Recently, it has been suggested that anti-third party CTLs depleted of alloreactivity are endowed with marked veto activity and therefore might potentially facilitate bone marrow allografting without graft versus host disease (GVHD). The veto mechanism is still obscure. While early studies emphasized the role of CD8-mediated apoptosis, more recent evidence indicates a role for Fas-FasL. In the present study we show, by using blocking anti-CD8 antibody, by generating CTLs from FasL or perforin mutated mice, and by gene transfer of FasL, that the veto activity of anti-third party CD8+ CTLs is dependent upon the simultaneous expression of both CD8 and FasL.

Characterization of a fibroblastoid mammary carcinoma cell line (LM2) originated from a mouse adenocarcinoma.

We established and characterized a new mammary tumor cell line, LM2, derived from M2 mammary adenocarcinoma which spontaneously appeared in a BALB/c female mouse. The LM2 cell line has been maintained in culture for more than 40 passages and grows as poorly differentiated elongated cells. Ultrastructural and immunocytochemistry analysis revealed characteristic features of adenocarcinoma. Cytogenetic studies showed that LM2 cells are fundamentally hypotetraploid. They express metalloproteinases (MMP) and show high levels of plasminogen activator type urokinase (uPA). They were sensitive to nitric oxide (NO)-mediated cytotoxicity when NO derived from an exogenous donor. In vivo, although LM2 cells were able to grow in the lungs, they could not metastasize to the same target organ from s.c. primary tumors. The LM2 mouse mammary adenocarcinoma cell line is a suitable model to examine different aspects of tumor biology, in particular those related to the different pathways involved in the metastatic cascade and in the cytotoxicity mediated by NO.

Comparison of the determination of superoxide dismutase and antioxidant capacity in neurological patients using two different procedures.

As oxidative stress in relation with neurological diseases has become an important point in recent research, simple methods to be used in epidemiological studies and clinical practice are required. The hypothesis that the analytical methods used in research laboratories (RLM) can be used interchangeably with commercial kits (CKM) for SOD and TRAP is tested. Both methods were compared using linear transformations of the RLM measurements into the CKM scales. Data were obtained from Alzheimer's, Parkinson's, and vascular dementia patients and controls. The lack of fit and the run's test of residuals were not significant, but the same sign method detected significant nonlinearities (P<0.000001 for SOD, P<0.01 for TRAP). The intragroup CVs of both methods were comparable for TRAP, while in the RLM determinations of SOD resulted in <50% of those obtained with the CKM. The ANCOVA comparison of the regression parameters across the clinical groups resulted significant for SOD (P<0.0001) and not significant for TRAP. Both methods agree in describing the features of the clinical groups, but the degree of agreement at the individual concentration was poor and they could not be readily intercalibrated. Normal and pathological values should be obtained independently for the CKM to insure their applicability to large populations.

[Nervous cells transplantation in neurodegenerative diseases]. / Trasplante de células nerviosas en enfermedades neurodegenerativas.

This article is a bibliographic review concerning the scientific advances in nervous tissue transplantation in experimental animals and in humans as applied to neurodegenerative diseases, particularly Parkinson's disease. Data show the possibility that the transplantation of nervous tissue may alleviate the typical symptoms of some of these diseases. Since the first trials in 1890, there has been a remarkable progress in this field, encouraging the idea that nervous tissue transplantation may be considered in clinical practice.

Trasplante de células nerviosas en enfermedades neurodegenerativas. / [Nervous cells transplantation in neurodegenerative diseases]

This article is a bibliographic review concerning the scientific advances in nervous tissue transplantation in experimental animals and in humans as applied to neurodegenerative diseases, particularly Parkinsons disease. Data show the possibility that the transplantation of nervous tissue may alleviate the typical symptoms of some of these diseases. Since the first trials in 1890, there has been a remarkable progress in this field, encouraging the idea that nervous tissue transplantation may be considered in clinical practice.

Induction of donor-type chimerism and transplantation tolerance across major histocompatibility barriers in sublethally irradiated mice by Sca-1(+)Lin(-) bone marrow progenitor cells: synergism with non-alloreactive (host x donor)F(1) T cells.

Induction of transplantation tolerance by means of bone marrow (BM) transplantation could become a reality if it was possible to achieve engraftment of hematopoietic stem cells under nonlethal preparatory cytoreduction of the recipient. To that end, BM facilitating cells, veto cells, or other tolerance-inducing cells, have been extensively studied. In the present study, we show that BM cells within the Sca-1(+)Lin(-) cell fraction, previously shown to be enriched for early hematopoietic progenitors, are capable of reducing specifically antidonor CTL-p frequency in vitro and in vivo, and of inducing split chimerism in sublethally 7-Gy-irradiated recipient mice across major histocompatibility complex barriers. The immune tolerance induced by the Sca-1(+)Lin(-) cells was also associated with specific tolerance toward donor-type skin grafts. The minimal number of cells required to overcome the host immunity remaining after 7 Gy total body irradiation is very large and, therefore, it may be very difficult to harvest sufficient cells for patients. This challenge was further addressed in our study by demonstrating that non-alloreactive (host x donor)F(1) T cells, previously shown to enhance T-cell-depleted BM allografts in lethally irradiated mice, synergize with Sca-1(+)Lin(-) cells in their capacity to overcome the major transplantation barrier presented by the sublethal mouse model.

Peripheral markers of oxidative stress in probable Alzheimer patients.

BACKGROUND: The current research on Alzheimer's disease is mainly focused in the post-mortem characterization of pathological and biochemical alterations in the brain. The finding of peripheral markers that could be associated with the changes observed in the Alzheimer's brain would be of interest in this field. The aim of the present study was to evaluate the state of different peripheral markers of oxidative stress in probable Alzheimer patients and compare them with a group of healthy individuals. DESIGN: The determinations made include the plasma total antioxidant capacity (TRAP) and tert-butyl hydroperoxide-initiated chemiluminescence and catalase activity in erythrocytes from 18 patients with probable Alzheimer's disease and 18 matched control subjects with normal cognitive function. RESULTS: TRAP was decreased in Alzheimer patients by 24% (control group 308 micromol L-1 Trolox, SEM 34, n = 18). tert-Butyl hydroperoxide-initiated chemiluminescence and catalase activity showed an increase in erythrocytes from Alzheimer patients by 52% (control group 116 700 cps mg-1 haemoglobin, SEM 6690) and 75% (control group 2.55 pmol mg-1 protein, SEM 0.39, n = 18) respectively. CONCLUSION: Oxidative stress in the blood of probable Alzheimer patients could be a reflection of the brain condition and suggests that oxygen free radicals could be partially responsible of the damage observed in this disease.

Soluble factors from the target organ enhance tumor cell angiogenesis: role of laminin SIKVAV sequence.

The ability of tumor cells to respond to microenvironmental factors present in the target organ determines in part the successful development of a metastasis. In a previous work it was demonstrated that the conditioned medium (CM) from lungs of normal mice stimulates in vitro migration, proliferation and uPA activity of cells from a murine mammary adenocarcinoma moderately metastatic to lung. This CM also enhanced local and metastatic tumor growth. Here, we show that lung CM enhanced neovascularization when inoculated together with LM3 tumor cells into the skin of syngeneic mice. A similar tumor-induced angiogenesis response was obtained when lung CM was injected systemically. Western blot analysis of lung CM revealed the presence of some laminin fragments containing the sequence SIKVAV. To determine whether those molecules were responsible for the observed angiogenic effects, the CM was depleted of the peptides containing the SIKVAV sequence. We observed that the SIKVAV-depleted lung CM lost its ability to induce an enhancement of the tumor neovascular response. Our results suggest a role for the target organ in facilitating the neovascularization of tumor cells, probably through the participation of active peptides derived from the proteolytic degradation of the basement membrane component laminin.

The role of megadose CD34+ progenitor cells in the treatment of leukemia patients without a matched donor and in tolerance induction for organ transplantation.

Throughout the 1980s, transplantation of unmodified (T cell-replete) bone marrow from full haplotype incompatible family donors was associated with an unsuccessful outcome because of graft failure and severe graft-versus-host disease (GVHD), at times affecting up to 90% of recipients. Although extensive T cell depletion of donor bone marrow was successful in preventing GVHD in children with severe combined immunodeficiency disease (SCID), results were disappointing in leukemic patients because the benefit of preventing GVHD was offset by graft failure. Resistance to engraftment appears to be mediated by host-derived cytotoxic T-lymphocyte precursors that survive supralethal conditioning. In the present paper, we review data that show that these genetic histocompatibility barriers can be overcome in stringent mouse models, employing lethally as well as sublethally irradiated recipients, by two major approaches that are synergistic to each other: escalation of hematopoietic progenitor cell dose and the use of nonalloreactive T cells. The former approach is already being successfully implemented in the treatment of leukemic patients.

Differential nitric oxide release and sensitivity to injury in different murine mammary tumor cell lines.

The purpose of this study was to determine whether nitric oxide (NO) production by different mammary tumor cell lines correlated with their sensitivity to NO mediated injury. Three mammary tumor cell lines LM2, LM3 and LMM3 syngeneic to BALB/c mice were cultured in vitro with IFNgamma + LPS. Different levels of NO production among the three lines were detected in culture supernatants. The only tumor cell line which did not produce NO (LM2) showed the highest sensitivity to SNP-derived NO cytotoxicity (87%), while LM3 and LMM3 which both produced higher levels of NO than LM2, showed lower cytotoxicity by SNP (39% and 22% respectively). Spleen cells (SC) from M2 tumor bearing mice (TBM) were able to lyse LM2 cells by NO-dependent mechanisms. SC from M3-TBM exerted cytotoxicity against LM3 cells mainly by NO-independent mechanisms. Thus, we postulate an inverse correlation between NO production and NO mediated cytotoxicity in the three mammary tumor cell lines. It is possible that tumor cells producing NO develop mechanisms to resist NO injury.