Combined Action of Shiga Toxin Type 2 and Subtilase Cytotoxin in the Pathogenesis of Hemolytic Uremic Syndrome.

Shiga toxin-producing E. coli (STEC) produces Stx1 and/or Stx2, and Subtilase cytotoxin (SubAB). Since these toxins may be present simultaneously during STEC infections, the purpose of this work was to study the co-action of Stx2 and SubAB. Stx2 + SubAB was assayed in vitro on monocultures and cocultures of human glomerular endothelial cells (HGEC) with a human proximal tubular epithelial cell line (HK-2) and in vivo in mice after weaning. The effects in vitro of both toxins, co-incubated and individually, were similar, showing that Stx2 and SubAB contribute similarly to renal cell damage. However, in vivo, co-injection of toxins lethal doses reduced the survival time of mice by 24 h and mice also suffered a strong decrease in the body weight associated with a lowered food intake. Co-injected mice also exhibited more severe histological renal alterations and a worsening in renal function that was not as evident in mice treated with each toxin separately. Furthermore, co-treatment induced numerous erythrocyte morphological alterations and an increase of free hemoglobin. This work shows, for the first time, the in vivo effects of Stx2 and SubAB acting together and provides valuable information about their contribution to the damage caused in STEC infections.

Absence of interleukin-10 reduces progression of shiga toxin-induced hemolytic uremic syndrome.

Hemolytic Uremic Syndrome (HUS), a disease triggered by Shiga toxin (Stx), is characterized by hemolytic anemia, thrombocytopenia and renal failure. The inflammatory response mediated by polymorphonuclear neutrophils (PMNs) and monocytes is essential to HUS onset. Still, the role of anti-inflammatory cytokines is less clear. The deficiency of IL-10, an anti-inflammatory cytokine, leads to severe pathology in bacterial infections but also to beneficial effects in models of sterile injury. The aim of this work was to analyze the role of IL-10 during HUS. Control and IL-10 lacking mice (IL-10-/-) were intravenously injected with Stx type 2 (Stx2) and survival rate was evaluated. PMN and circulating and renal pro- and anti-inflammatory factors were analyzed by FACS and enzyme-linked immunosorbent assay (ELISA) respectively. IL-10-/- mice showed a higher survival associated with lower renal damage reflected by reduced plasma urea and creatinine levels than control mice. Circulating PMN increased at 72 h in both mouse strains accompanied by an up-regulation of CD11b in control mice. In parallel, renal PMN were significantly increased only in control mice after toxin. Plasma TNF-α, IL-6 and corticosterone levels were higher increased in IL-10-/- than control mice. Simultaneously renal TNF-α raised constantly but was accompanied by increased TGF-ß levels in IL-10-/- mice. These results demonstrate that the profile of circulating and renal cytokines after Stx2 differed between strains suggesting that balance of these factors could participate in renal protection. We conclude that IL-10 absence has a protective role in an experimental model of HUS by reducing PMN recruitment into kidney and renal damage, and increasing mice survival.

In Vivo Photodynamic Therapy With a Lipophilic Zinc(II) Phthalocyanine Inhibits Colorectal Cancer and Induces a Th1/CD8 Antitumor Immune Response.

BACKGROUND AND OBJECTIVES: Photodynamic therapy (PDT) is an antitumor procedure clinically approved for the treatment of different cancer types. Despite strong efforts and promising results in this field, PDT has not yet been approved by any regulatory authority for the treatment of colorectal cancer, one of the most prevalent gastrointestinal tumors. In the search of novel therapeutic strategies, we examined the in vivo effect of PDT with a lipophilic phthalocyanine (Pc9) encapsulated into polymeric poloxamine micelles (T1107) in a murine colon carcinoma model. STUDY DESIGN/MATERIALS AND METHODS: In vivo assays were performed with BALB/c mice challenged with CT26 cells. Pc9 tumor uptake was evaluated with an in vivo imaging system. Immunofluorescence, western blot, and flow cytometry assays were carried out to characterize the activation of apoptosis and an antitumor immune response. RESULTS: Pc9-T1107 effectively delayed tumor growth and prolonged mice survival, without generating systemic or tissue-specific toxicity. The induction of an apoptotic response was characterized by a decrease in the expression levels of Bcl-XL , Bcl-2, procaspase 3, full length Bid, a significant increment in the amount of active caspase-3 and the detection of PARP-1 cleavage. Infiltration of CD8+ CD107a+ T cells and higher levels of interferon-γ and tumor necrosis factor-α were also found in PDT-treated tumors. CONCLUSIONS: Pc9-T1107 PDT treatment reduced tumor growth, inducing an apoptotic cell death and activating an immune response. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Exposure to growth hormone is associated with hepatic up-regulation of cPLA2α and COX.

Continuously elevated levels of growth hormone (GH) during life in mice are associated with hepatomegaly due to hepatocytes hypertrophy and hyperplasia, chronic liver inflammation, elevated levels of arachidonic acid (AA) at young ages and liver tumors development at old ages. In this work, the hepatic expression of enzymes involved in AA metabolism, cPLA2α, COX1 and COX2 enzymes, was evaluated in young and old GH-transgenic mice. Mice overexpressing GH exhibited higher hepatic expression of cPLA2α, COX1 and COX2 in comparison to controls at young and old ages and in both sexes. In old mice, when tumoral and non-tumoral tissue were compared, elevated expression of COX2 was observed in tumors. In contrast, exposure to continuous lower levels of hormone for a short period affected COX1 expression only in males. Considering the role of inflammation during liver tumorigenesis, these findings support a role of alterations in AA metabolism in GH-driven liver tumorigenesis.

Expression of estrogen receptor α variants and c-Fos in rat mammary gland and tumors.

Breast cancer is currently the leading cause of cancer death among women worldwide. AP-1 (c-Fos/c-Jun) is associated with proliferation and survival, while cytoplasmic c-Fos activates phospholipid synthesis in cells induced to differentiate or grow. Estrogen receptor α 46 (ERα46) is a splice variant of full-length ERα66 and it is known that it has an inhibitory role in cancer cell growth. We investigated c-Fos localization, its relationship to AP-1, the non genomic pathway of phospho-Tyr537-ERα66, as well as ERα46 and ERα66 isoforms in rat mammary gland development and carcinogenic transformation, and in mammary tumors. Female rats were injected: a) saline solution (Control mammary gland, CMG) or b) N-Nitroso-N-methyl urea (NMU), and samples were taken at 60, 90, 120 and 150 days of life. In addition, we analyzed hormone-dependent (HD) and independent (HI) tumors in ovariectomized rats, and intact tumors (IT) in non-ovariectomized ones. Our results show that, in CMG, nuclear c-Fos and proliferation decreased with age, AP-1 content was low, and nuclear ERα46/ERα66 ratio was higher than 1. In NMU, nuclear c-Fos and proliferation increased with carcinogenic transformation, AP-1 content was high, and nuclear ERα46/ERα66 was below 1. As tumor grade increased, proliferation, nuclear c-Fos and AP-1 expression were negatively associated to nuclear ERα46/ERα66 in IT. In HD, nuclear ERα46/ERα66, nuclear c-Fos expression, AP-1 levels and proliferation were lower than in HI, whose growth is estrogen-independent. Phospho-Tyr537-ERα66 content and ERK1/2 activation were associated with AP-1 levels and cell proliferation. Collectively, our findings support the notion that variant detection and ERα46/ERα66 ratio could shed light on the role of ERα isoforms in mammary gland transformation and the behavior of ERα positive mammary tumors.

Erythropoietin Improves Cardiovascular Function in Adult Rats After Acute Hemorrhage.

Erythropoietin (EPO) has been linked to cardioprotective effects. However, its effects during the aging process are little known. We investigated the effect of EPO administration on hemodynamic parameters, cardiac function, oxidative damage, and erythropoietin receptor (EPOR) expression pattern in the hypovolemic state. EPO was administered (1000 IU/kg/3 days) and then acute hemorrhage (20% blood loss) was induced in young and adult rats. There was no difference in plasmatic EPO in either age group. The hemodynamic basal condition was similar, without alterations in renal function and hematocrit, in both age groups. After bleeding, both EPO-treated age groups had increased blood pressure at the end of the experimental protocol, being greater in adult animals. EPO attenuated the tachycardic effect. Ejection fraction and fractional shortening were higher in adult EPO-treated rats subjected to hemorrhage. In the left ventricle, young and adult EPO-treated rats subjected to bleeding showed an increased EPOR expression. A different EPOR expression pattern was observed in the adult right atrial tissue, compared with young animals. EPO treatment decreased oxidative damage to lipids in both age groups. EPO treatment before acute hemorrhage improves cardiovascular function during the aging process, which is mediated by different EPOR pattern expression in the heart tissue.

Podocyturia in paediatric patients with Fabry disease. / Podocituria en pacientes pediátricos con enfermedad de Fabry.

INTRODUCTION: Fabry disease (FD) is a hereditary disorder caused by a deficiency of α-galactosidase A enzyme activity. The transmission of the disorder is linked to the X chromosome. OBJECTIVES: The objectives of the study were: 1. To quantify the presence of podocytes in paediatric patients with FD and compare them with the value of the measured podocyturia in healthy controls. 2. To determine whether a greater podocyturia is related to the onset of pathological albuminuria in patients with FD. 3. To determine the risk factors associated with pathological albuminuria. METHODS: We performed an analytical, observational study of Fabry and control subjects, which were separated into 2groups in accordance with the absence of the disease (control group) or the presence of the disease (Fabry group). RESULTS: We studied 31 patients, 11 with FD and 20 controls, with a mean age of 11.6 years. The difference between the mean time elapsed from the diagnosis of FD to the measurement of podocyturia (40 months) and the onset of pathological albuminuria (34 months) was not significant (p=0.09). Podocytes were identified by staining for the presence of synaptopodin and the mean quantitative differences between both podocyturias were statistically significant (p=0.001). Albuminuria was physiological in 4 of the patients with FD and the relative risk to develop pathological albuminuria according to podocyturia was 1.1 in the control group and 3.9 in the Fabry group, with a coefficient of correlation between podocyturia and albuminuria in the Fabry group of 0.8354. Finally, the 2 risk factors associated with the development of pathological albuminuria were podocyturia (OR: 14) and being aged over 10 years (OR: 18). We found no significant risk with regard to glomerular filtrate renal (GFR) (OR: 0.5) or gender (OR: 1.3). The mean GFR remained within normal values. CONCLUSION: The detection of podocyturia in paediatric patients with FD could be used as an early marker of renal damage, preceding and proportional to the occurrence of pathological albuminuria.

Trophoblast VIP deficiency entails immune homeostasis loss and adverse pregnancy outcome in mice.

Immune homeostasis maintenance throughout pregnancy is critical for normal fetal development. Trophoblast cells differentiate into an invasive phenotype and contribute to the transformation of maternal arteries and the functional shaping of decidual leukocyte populations. Insufficient trophoblast invasion, inadequate vascular remodeling, and a loss of immunologic homeostasis are associated with pregnancy complications, such as preeclampsia and intrauterine growth restriction. Vasoactive intestinal peptide (VIP) is a pleiotropic neuropeptide synthetized in trophoblasts at the maternal-placental interface. It regulates the function of trophoblast cells and their interaction with decidual leukocytes. By means of a murine model of pregnancy in normal maternal background with VIP-deficient trophoblast cells, here we demonstrate that trophoblast VIP is critical for trophoblast function: VIP gene haploinsufficiency results in lower matrix metalloproteinase 9 expression, and reduced migration and invasion capacities. A reduced number of regulatory T cells at the implantation sites along with a lower expression of proangiogenic and antiinflammatory markers were also observed. Findings detected in the implantation sites at early stages were followed by an abnormal placental structure and lower fetal weight. This effect was overcome by VIP treatment of the early pregnant mice. Our results support the relevance of trophoblast-synthesized VIP as a critical factor in vivo for trophoblast-cell function and immune homeostasis maintenance in mouse pregnancy.-Hauk, V., Vota, D., Gallino, L., Calo, G., Paparini, D., Merech, F., Ochoa, F., Zotta, E., Ramhorst, R., Waschek, J., Leirós, C. P. Trophoblast VIP deficiency entails immune homeostasis loss and adverse pregnancy outcome in mice.

Exposure to environmental concentrations of hexachlorobenzene induces alterations associated with endometriosis progression in a rat model.

Hexachlorobenzene (HCB) is a dioxin-like compound widely distributed and is a weak ligand of the aryl hydrocarbon receptor (AhR). Endometriosis is a disease characterized by growth of endometrial tissue in ectopic sites. Our aim was to investigate the impact of HCB on the endocrine, invasion and inflammatory parameters in a rat endometriosis model surgically induced. Female rats were exposed to HCB (1, 10 and 100 mg/kg b.w.) during 30 days. Results showed that HCB increases endometriotic like-lesions (L) volume in a dose-dependent manner. In L, HCB10 increases microvessel density (immunohistochemistry) and the vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2) and AhR levels (Western Blot), while HCB1 enhances aromatase expression (Western Blot). In addition, in eutopic endometrium (EU), HCB10/HCB100 augments microvessel density, VEGF and MMP-9 expression, while HCB1/HCB10 increases tumor necrosis factor-α (TNF-α) content in peritoneal fluid (ELISA). Interestingly, both L and EU from HCB-treated rats exhibited higher estrogen receptor α (ERα) (immunohistochemistry) and metalloproteases (MMP)-2 and -9 levels (Western Blot), as well as lower progesterone receptor (PR) expression (immunohistochemistry) than in control rats. Environmentally relevant concentrations of HCB could contribute to abnormal changes associated with endometriosis progression and development.

A novel penicillin derivative induces antitumor effect in melanoma cells.

In this study, we explored the in-vitro and in-vivo mechanism of antitumor action of a novel synthetic nonantibiotic triazolylpeptidyl penicillin derivative, named TAP7f, on B16-F0 murine melanoma cells. In-vitro assays showed that TAP7f caused an inhibition of S phase progression and a concomitant decrease of the percentage of cells in G0/G1 phase. We also found that TAP7f treatment induced an apoptotic response characterized by an increase of the sub-G1 fraction of B16-F0 hypodiploid cells, the occurrence of cells with picnotic nuclei, and the detection of phosphatidylserine exposure on the outer side of the plasma membrane. Apoptotic cell death was further characterized by the activation of caspase-8, caspase-9, and caspase-3; the increase in the proapoptotic/antiapoptotic ratio of Bcl-2 family proteins; the higher expression levels of Fas receptor and TRAIL ligand; and the cleavage of poly(ADP-ribose) polymerase, a caspase-3 substrate. The in-vivo effect of TAP7f was studied in a syngeneic C57BL/6J mouse melanoma model. Results showed that TAP7f inhibited melanoma cell proliferation in vivo, as determined by a decreased expression of proliferating cell nuclear antigen, inducing a significant reduction of tumor growth. Apoptosis in vivo was assessed by detecting active caspase-3 in tumor slices from treated mice and the expression levels of Fas, TRAIL, and Bcl-2 proteins in tumor lysates. The administration of 80 mg/kg of TAP7f to non-tumor-bearing mice showed no histopathological effects on different organ tissues. Our results suggest that TAP7f might be considered as a potential therapeutic agent for cancer treatment.

El síndrome urémico hemolítico y manejo renal de proteínas / Hemolytic uremic syndrome and renal handling of proteins

El síndrome urémico hemolítico (SUH) está definido por la tríada de anemia hemolítica microangiopática, trombocitopenia e insuficiencia renal aguda. En Argentina constituye la primera causa de insuficiencia renal aguda en pediatría. Aproximadamente, del 2% al 4% de los pacientes mueren durante la fase aguda de la enfermedad, y solo un tercio del 96% restante que sobrevive lo hace con secuelas renales, como la persistencia de la proteinuria. Un individuo adulto sano filtra alrededor de 5000 mg/día de proteínas, si bien la excreción en orina es escasa (150 mg/día). La escasa cantidad de proteínas excretadas indica la presencia de un mecanismo de reabsorción a nivel del túbulo proximal. Por lo tanto, la reabsorción tubular renal desempeña un papel muy importante ya que, ante una función glomerular normal, es el principal mecanismo encargado de evitar la depleción proteica corporal. Desde hace aproximadamente 30 años se sabe que la albúmina es reabsorbida en el túbulo proximal. La reabsorción proteica se produce por un mecanismo de endocitosis mediada por el receptor dependiente de clatrina y por endocitosis de fase líquida. Clásicamente se ha descrito que el mecanismo básico del daño renal en el SUH típico y en el atípico es una microangiopatía trombótica, pero de diferentes causas. Sin embargo, debe tenerse en cuenta que la fisiopatología de esta enfermedad es más compleja de lo que se creía, ya que la alteración tubular que surge va a evolucionar en fallas en el mecanismo de endocitosis de proteínas que se suman a las eliminadas por las alteraciones a nivel de la barrera de filtración glomerular.

Hemolytic uremic syndrome (HUS) is defined by the triad of hemolytic anemia microangiopathic, thrombocytopenia and acute renal failure. In Argentina it constitutes the first cause of acute renal failure in Pediatrics. Approximately 2-4% of patients die during the acute phase of the disease, and only a third of the remaining 96% survive with renal sequelae, such as the persistence of proteinuria. A healthy adult filters around 5000 mg/day of proteins, with an excretion in urine of 150 mg/day. The little quantity of proteins excreted indicates the presence of a reabsorption mechanism at the level of the proximal tubule. Therefore, the tubular reabsorption plays a very important role since it is the main mechanism responsible for preventing the depletion of protein. For approximately 30 years, it has been known that albumin is reabsorbed in the proximal tubule. Protein reabsorption occurs by a clathrin-dependent receptor mediated endocytosis mechanism and by fluid phase endocytosis. The basic mechanism of renal damage in typical and atypical HUS has been described as a thrombotic microangiopathy, but of different causes. However, the pathophysiology of this disease is more complex than what was believed since the emerging tubular alteration will ewvolve into failures of the protein endocytosis mechanism that are added to the alterations at the level of the glomerular filtration barrier.

Immunization of pregnant cows with Shiga toxin-2 induces high levels of specific colostral antibodies and lactoferrin able to neutralize E. coli O157:H7 pathogenicity.

E. coli O157:H7 is a foodborne pathogen responsible for bloody diarrhea, hemorrhagic colitis and hemolytic uremic syndrome (HUS). The objective of the present work was to evaluate the ability of colostral IgG obtained from Stx2-immunized cows to prevent against E. coli O157:H7 infection and Stx2 cytotoxicity. Hyperimmune colostrum (HC) was obtained from cows intramuscularly immunized with inactivated Stx2 or vehicle for controls. Colostral IgG was purified by affinity chromatography. Specific IgG antibodies against Stx2 and bovine lactoferrin (bLF) levels in HC and the corresponding IgG (HC-IgG/bLF) were determined by ELISA. The protective effects of HC-IgG/bLF against Stx2 cytotoxicity and adhesion of E. coli O157:H7 and its Stx2-negative mutant were analyzed in HCT-8 cells. HC-IgG/bLF prevention against E. coli O157:H7 was studied in human colon and rat colon loops. Protection against a lethal dose of E. coli O157:H7 was evaluated in a weaned mice model. HC-IgG/bLF showed high anti-Stx2 titers and high bLF levels that were able to neutralize the cytotoxic effects of Stx2 in vitro and in vivo. Furthermore, HC-IgG/bLF avoided the inhibition of water absorption induced by E. coli O157:H7 in human colon and also the pathogenicity of E. coli O157:H7 and E. coli O157:H7Δstx2 in rat colon loops. Finally, HC-IgG/bLF prevented in a 100% the lethality caused by E. coli O157:H7 in a weaned mice model. Our study suggests that HC-IgG/bLF have protective effects against E. coli O157:H7 infection. These beneficial effects may be due to specific anti-Stx2 neutralizing antibodies in combination with high bLF levels. These results allow us to consider HC-IgG/bLF as a nutraceutical tool which could be used in combination with balanced supportive diets to prevent HUS. However further studies are required before recommendations can be made for therapeutic and clinical applications.

A dioxin-like compound induces hyperplasia and branching morphogenesis in mouse mammary gland, through alterations in TGF-ß1 and aryl hydrocarbon receptor signaling.

Hexachlorobenzene (HCB) is a widespread environmental pollutant and a dioxin-like compound that binds weakly to the aryl hydrocarbon receptor (AhR). Because AhR and transforming growth factor ß1 (TGF-ß1) converge to regulate common signaling pathways, alterations in this crosstalk might contribute to developing preneoplastic lesions. The aim of this study was to evaluate HCB action on TGF-ß1 and AhR signaling in mouse mammary gland, through AhR+/+ and AhR-/- models. Results showed a differential effect in mouse mammary epithelial cells (NMuMG), depending on the dose: 0.05µM HCB induced cell migration and TGF-ß1 signaling, whereas 5µM HCB reduced cell migration, promoted cell cycle arrest and stimulated the dioxin response element (DRE) -dependent pathway. HCB (5µM) enhanced α-smooth muscle actin expression and decreased TGF-ß receptor II mRNA levels in immortalized mouse mammary fibroblasts AhR+/+, resembling the phenotype of transformed cells. Accordingly, their conditioned medium was able to enhance NMuMG cell migration. Assays in C57/Bl6 mice showed HCB (3mg/kg body weight) to enhance ductal hyperplasia, cell proliferation, estrogen receptor α nuclear localization, branch density, and the number of terminal end buds in mammary gland from AhR+/+ mice. Primary culture of mammary epithelial cells from AhR+/+ mice showed reduced AhR mRNA levels after HCB exposure (0.05 and 5µM). Interestingly, AhR-/- mice exhibited an increase in ductal hyperplasia and mammary growth in the absence of HCB treatment, thus revealing the importance of AhR in mammary development. Our findings show that environmental HCB concentrations modulate AhR and TGF-ß1 signaling, which could contribute to altered mammary branching morphogenesis, likely leading to preneoplastic lesions and retaining terminal end buds.

In IgA Nephropathy, Glomerulosclerosis Is Associated with Increased Urinary CD80 Excretion and Urokinase-Type Plasminogen Activator Receptor-Positive Podocyturia.

BACKGROUND: Podocyturia may determine the evolution to podocytopenia, glomerulosclerosis, and renal failure. According to the Oxford classification of IgA nephropathy (IgAN), the S1 lesion describes glomerulosclerosis. Urokinase-type plasminogen activator receptor (uPAR) participates in podocyte attachment, while CD80 increases in glomerulosclerosis. We measured uPAR-positive urinary podocytes and urinary CD80 (uCD80) in controls and in IgAN subjects with M1E0S0T0 and M1E0S1T0 Oxford scores to assess a potential association between podocyturia, inflammation, and glomerulosclerosis. METHODS: The groups were as follows: controls (G1), n = 20 and IgAN group (G2), n = 39, subdivided into M1E0S0T0 (G2A), n = 21 and M1E0S1T0 (G2B), n = 18. Among the included variables, we determined uPAR-positive podocytes/gram of urinary creatinine (gUrCr) and uCD80 ng/gUrCr. Biopsies with interstitial fibrosis and tubular atrophy <10% were included. RESULTS: Groups were not different in age and gender; urinary protein-creatinine (uP/C) ratio, Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation, uPAR-positive podocytes/gUrCr, and uCD80 were significantly increased in G2 versus G1. G2A and G2B were not different in age, gender, hypertension, and follow-up. G2B displayed significantly higher uP/C, uPAR-positive podocytes, uCD80, and lower CKD-EPI versus G2A. Strong significant correlations were encountered between uCD80 and podocyturia in G2A and G2B. However, when G1 was compared to G2A and G2B separately, the differences with respect to uP/C, uPAR-positive podocytes, and podocyturia were significantly stronger versus G2B than versus G2A. CONCLUSIONS: IgAN presents elevated uCD80 excretion and uPAR-positive podocyturia, while CD80 correlates with podocyturia. Glomerulosclerosis (S1) at the time of biopsy is associated with higher uP/C, lower renal function, increased uPAR-positive podocyturia, and CD80 excretion, and is independent of M1. In IgAN, uPAR may participate in podocyte detachment.

Low molecular weight hyaluronan induces migration of human choriocarcinoma JEG-3 cells mediated by RHAMM as well as by PI3K and MAPK pathways.

Hyaluronan (HA) is the major glycosaminoglycan present in the extracellular matrix. It is produced by some tumours and promotes proliferation, differentiation and migration among others cellular processes. Gestational trophoblastic disease (GTD) is composed by non-tumour entities, such as hydatidiform mole (HM), which is the most common type of GTD and also malignant entities such as choriocarcinoma (CC) and placental site trophoblastic tumour (PSTT), being CC the most aggressive tumour. Although there is a growing understanding of GTD biology, the role of HA in the pathogenesis of this group of diseases remains largely unknown. The aim of this work was to study the role of HA in the pathogenesis of GTD by defining the expression pattern of HA and its receptors CD44 and RHAMM, as well as to determine if HA can modulate proliferation, differentiation and migration of CC cells. Receptors and signalling pathways involved were also analyzed. We demonstrated that HA and RHAMM are differently expressed among GTD entities and even among trophoblast subtypes. We also showed that HA is able to enhance the expression of extravillous trophoblast markers and also to induce migration of JEG-3 cells, the latter mediated by RHAMM as well as PI3K and MAPK pathways. These findings indicate a novel regulatory mechanism for CC cell biology and also contribute to the understanding of GTD pathophysiology.

Endogenous lysophosphatidic acid participates in vascularisation and decidualisation at the maternal-fetal interface in the rat.

Lysophosphatidic acid (LPA) affects several female reproductive functions through G-protein-coupled receptors. LPA contributes to embryo implantation via the lysophospholipid LPA3 receptor. In the present study we investigated the participation of endogenous LPA signalling through the LPA3 receptor in vascularisation and decidualisation, two crucial events at the maternal-fetal interface. Pregnant rats were treated with diacylglycerol pyrophosphate (DGPP), a highly selective antagonist of LPA3 receptors, on Day 5 of gestation. Pregnant rats received intrauterine (i.u.) injections of single doses of DGPP (0.1mgkg-1) in a total volume of 2µL in the left horn (treated horn) in the morning of GD5. DGPP treatment produced aberrant embryo spacing and increased embryo resorption. The LPA3 receptor antagonist decreased the cross-sectional length of the uterine and arcuate arteries and induced histological anomalies in the decidua and placentas. Marked haemorrhagic processes, infiltration of immune cells and tissue disorganisation were observed in decidual and placental tissues from sites of resorption. The mRNA expression of three vascularisation markers, namely interleukin 10 (Il10), vascular endothelial growth factor (Vegfa) and vascular endothelial growth factor receptor 1 (Vegfr1), was reduced at sites of resorption from Day 8. The results show that the disruption of endogenous LPA signalling by blocking the LPA3 receptor modified the development of uterine vessels with consequences in the formation of the decidua and placenta and in the growth of embryos.

Effects of nitric oxide system and osmotic stress on Aquaporin-1 in the postnatal heart.

Aquaporin-1 (AQP1) is expressed in the heart and its relationship with NO system has not been fully explored. The aims of this work were to study the effects of NO system inhibition on AQP1 abundance and localization and evaluate AQP1 S-nitrosylation in a model of water restriction during postnatal growth. Rats aged 25 and 50days (n=15) were divided in: R: water restriction; C: water ad libitum; RL: L-NAME (4mg/kgday)+water restriction; CL: L-NAME+water ad libitum. AQP1 protein levels, immunohistochemistry and S-nitrosylation (colocalization of AQP1 and S-nitrosylated cysteines by confocal microscopy) were determined in cardiac tissue. We also evaluated the effects of NO donor sodium nitroprusside (SNP) on osmotic water permeability of cardiac membrane vesicles by stopped-flow spectrometry. AQP1 was present in cardiac vascular endothelium and endocardium in C and CL animals of both ages. Cardiac AQP1 levels were increased in R50 and RL50 and appeared in cardiomyocyte plasma membrane. No changes in AQP1 abundance or localization were observed in R25, but RL25 group showed AQP1 presence on cardiomyocyte sarcolemma. AQP1 S-nitrosylation was increased in R25 group, without changes in the 50-day-old group. Cardiac membrane vesicles expressing AQP1 presented a high water permeability coefficient and pretreatment with SNP decreased water transport. Age-related influence of NO system on AQP1 abundance and localization in the heart may affect cardiac water homeostasis during hypovolemic state. Increased AQP1 S-nitrosylation in the youngest group may decrease osmotic water permeability of cardiac membranes, having a negative impact on cardiac water balance.

Podocyturia is significantly elevated in untreated vs treated Fabry adult patients.

BACKGROUND: Proteinuria suggests kidney involvement in Fabry disease. We assessed podocyturia, an early biomarker, in controls and patients with and without enzyme therapy, correlating podocyturia with proteinuria and renal function. METHODS: Cross-sectional study (n = 67): controls (Group 1, n = 30) vs. Fabry disease (Group 2, n = 37) subdivided into untreated (2A, n = 19) and treated (2B, n = 18). Variables evaluated: age, gender, creatinine, CKD-EPI, proteinuria, podocyte count/10 20× microscopy power fields, podocytes/100 ml urine, podocytes/g creatininuria (results expressed as median and range). RESULTS: Group 1 vs. 2 did not differ concerning age, gender and CKD-EPI, but differed regarding proteinuria and podocyturia. Group 2A vs. 2B: age: 29 (18-74) vs. 43 (18-65) years (p = ns); gender: males n = 3 (16 %) vs. n = 9 (50 %). Proteinuria was significantly higher in Fabry treated patients, while CKD-EPI and podocyturia were significantly elevated in untreated individuals. Significant correlations: group 2A: age-proteinuria, ρ = 0.62 (p = 0.0044); age-CKD-EPI, ρ = -0.84 (p < 0.0001); podocyturia-podocytes/100 ml urine, ρ = 0.99 (p = 0.0001); podocyturia-podocytes/g creatininuria ρ = 0.86 (p = 0.0003), podocytes/100 ml urine-podocytes/g urinary creatinine, ρ = 0.84 (p = 0.0004); proteinuria-CKD-EPI, ρ = -0.68 (p = 0.0013). Group 2B: podocyturia-podocytes/100 ml urine, ρ = 0.88 (p < 0.0001); podocyturia-podocytes/g creatininuria, ρ = 0.84 (p < 0.0001); podocytes/100 ml urine-podocytes/g creatininuria, ρ = 0.94 (p < 0.0001); CKD-EPI-proteinuria, ρ = -0.66 (p = 0.0028). CONCLUSIONS: Patients with Fabry disease display heavy podocyturia; those untreated present significantly higher podocyturia, lower proteinuria and better renal function than those who are treated, suggesting that therapy may be started at advanced stages. Podocyturia may antedate proteinuria, and enzyme therapy may protect against podocyte loss.

Clade 8 and Clade 6 Strains of Escherichia coli O157:H7 from Cattle in Argentina have Hypervirulent-Like Phenotypes.

The hemolytic uremic syndrome (HUS) whose main causative agent is enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a disease that mainly affects children under 5 years of age. Argentina is the country with the highest incidence of HUS in the world. Cattle are a major reservoir and source of infection with E. coli O157:H7. To date, the epidemiological factors that contribute to its prevalence are poorly understood. Single nucleotide polymorphism (SNP) typing has helped to define nine E. coli O157:H7 clades and the clade 8 strains were associated with most of the cases of severe disease. In this study, eight randomly selected isolates of EHEC O157:H7 from cattle in Argentina were studied as well as two human isolates. Four of them were classified as clade 8 through the screening for 23 SNPs; the two human isolates grouped in this clade as well, while two strains were closely related to strains representing clade 6. To assess the pathogenicity of these strains, we assayed correlates of virulence. Shiga toxin production was determined by an ELISA kit. Four strains were high producers and one of these strains that belonged to a novel genotype showed high verocytotoxic activity in cultured cells. Also, these clade 8 and 6 strains showed high RBC lysis and adherence to epithelial cells. One of the clade 6 strains showed stronger inhibition of normal water absorption than E. coli O157:H7 EDL933 in human colonic explants. In addition, two of the strains showing high levels of Stx2 production and RBC lysis activity were associated with lethality and uremia in a mouse model. Consequently, circulation of such strains in cattle may partially contribute to the high incidence of HUS in Argentina.