AgeR deletion decreases soluble fms-like tyrosine kinase 1 production and improves post-ischemic angiogenesis in uremic mice

Peripheral arterial disease occurs more frequently and has a worse prognosis in patients with chronic kidney disease (CKD). The receptor for advanced glycation end products (RAGE) is involved in multiple aspects of uremia-associated vasculopathy. Previous data suggest that the RAGE pathway may promote soluble fms-like tyrosine kinase 1 (sFlt1) production, an anti-angiogenic molecule. Thus, we tested the hypothesis that the deletion of AgeR would decrease sFlt1 production and improve post-ischemic revascularization in uremic condition. We used a well-established CKD model (5/6 nephrectomy) in WT and AgeR-/- C57/Bl6 mice. Hindlimb ischemia was induced by femoral artery ligation. Revascularization was evaluated by complementary approaches: ischemic limb retraction, LASCA imagery, and capillary density. The production of sFlt1 was assessed at both RNA and protein levels. After hindlimb ischemia, uremic mice showed slower functional recovery (p < 0.01), decreased reperfusion (p < 0.01), lower capillary density (p = 0.02), and increased circulating sFlt1 levels (p = 0.03). AgeR deletion restored post-ischemic angiogenesis and was protective from sFlt1 increase in uremic mice. These findings show the main role of RAGE in post-ischemic angiogenesis impairment associated with CKD. RAGE may represent a key target for building new therapeutic approaches to improve the outcome of CKD patients with PAD.

Complementary Role of P2 and Adenosine Receptors in ATP Induced-Anti-Apoptotic Effects Against Hypoxic Injury of HUVECs

BACKGROUND

Vascular endothelial injury during ischemia generates apoptotic cell death and precedes apoptosis of underlying tissues. We aimed at studying the role of extracellular adenosine triphosphate (ATP) on endothelial cells protection against hypoxia injury.

METHODS

In a hypoxic model on endothelial cells, we quantified the extracellular concentration of ATP and adenosine. The expression of mRNA (ectonucleotidases, adenosine, and P2 receptors) was measured. Apoptosis was evaluated by the expression of cleaved caspase 3. The involvement of P2 and adenosine receptors and signaling pathways was investigated using selective inhibitors.

RESULTS

Hypoxic stress induced a significant increase in extracellular ATP and adenosine. After a 2-h hypoxic injury, an increase of cleaved caspase 3 was observed. ATP anti-apoptotic effect was prevented by suramin, pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), and CGS15943, as well as by selective A2A, A2B, and A3 receptor antagonists. P2 receptor-mediated anti-apoptotic effect of ATP involved phosphoinositide 3-kinase (PI3K), extracellular signal-regulated kinases (ERK1/2), mitoK_ATP, and nitric oxide synthase (NOS) pathways whereas adenosine receptor-mediated anti-apoptotic effect involved ERK1/2, protein kinase A (PKA), and NOS.

CONCLUSIONS

These results suggest a complementary role of P2 and adenosine receptors in ATP-induced protective effects against hypoxia injury of endothelial. This could be considered therapeutic targets to limit the development of ischemic injury of organs such as heart, brain, and kidney.

Fondaparinux upregulates thrombomodulin and the endothelial protein C receptor during early-stage reperfusion in a rat model of myocardial infarction

INTRODUCTION

Fondaparinux (FDX) was demonstrated to be cardioprotective in a rat model of myocardial ischemia reperfusion. In this model, FDX reduced infarct size after 2h of reperfusion, involving the activation of the survivor activating factor enhancement (SAFE) pathway as early as 30min post-reperfusion. Our aim was to study if this cardioprotection could be explained by anti-inflammatory mechanisms and a protective effect on vessels.

METHODS

Wistar male rats were subjected to 40minutes (min) of myocardial ischemia, followed by 30min or 2h of reperfusion. Rats were randomized into four groups: control 30min (n=7), FDX 30min (n=7), control 2h (n=7), and FDX 2h (n=7). The FDX groups received 10mg/kg injection of FDX 10min prior to initiating reperfusion. We studied: 1) mRNA expression of endothelial markers, such as thrombomodulin (TM), endothelial protein C receptor (EPCR), and tissue factor (TF) and 2) proteic expression of ICAM-1, NF-κB, IκB, and JNK. Leukocyte infiltration was assessed by histochemistry. We also evaluated TM and EPCR mRNA expression in a model of isolated rat mesenteric arteries incubated with FDX.

RESULTS

FDX upregulated the expression of TM and EPCR mRNA in the models of myocardial infarction and isolated mesenteric arteries. No difference was observed between the treated and control groups regarding the expression of pro-inflammatory signaling proteins, adhesion molecules, and leukocyte infiltration after 2h of reperfusion.

CONCLUSION

The cardioprotective effect of FDX at early-stage reperfusion could be related to vascular protection, yet not to an anti-inflammatory effect.

Tissue factor up-regulation in proinflammatory conditions confers thrombin generation capacity to endothelial colony-forming cells without influencing non-coagulant properties in vitro

BACKGROUND

Endothelial progenitor cells (EPC) are good candidates for cell-based therapy in cardiovascular diseases. However, concerns have been raised about the potential risks of EPC-based cell therapy, in terms of thrombogenicity particularly in inflammatory conditions, currently observed in such patients. Tissue factor (TF) can trigger coagulation and may support thrombogenicity. TF is also a key receptor in angiogenesis.

OBJECTIVE

The present study was designed to (i) evaluate the capacity of resting and tumour necrosis factor-alpha (TNF)-α-stimulated late-outgrowth endothelial colony-forming cells (ECFCs) to express TF and (ii) investigate the effect of TF/FVII(a) interaction on procoagulant and non-procoagulant activities of ECFCs in vitro.

METHODS

ECFCs from cord blood (cb) and adult peripheral blood (ab) were analyzed for TF expression and activity using reverse transcription-polymerase chain reaction (RT-PCR), flow cytometry, Western blot and a thrombin generation assay. Non-procoagulant properties of TF-expressing ECFCs were investigated in vitro using wound-healing, cell proliferation, tube formation and spheroid-based assays.

RESULTS

ECFCs expressed TF in response to TNF-α. The up-regulation of TF conferred to ECFCs a FVII(a)-dependent thrombin generation activity. Compared with cb-ECFC, ab-ECFCs can display a higher level of constitutive TF expression and activity, with a notable heterogeneity among donors. TF/FVIIa interaction did not modify non-procoagulant properties of TNF-α stimulated cb-ECFCs in vitro.

CONCLUSIONS

Proinflammatory conditions up-regulate TF expression in ECFCs. This expression confers to ECFCs a strong thrombin generation capacity without influencing their non-coagulant properties. Our results suggest that EPC-based cell therapy may be associated with prothrombotic risk which could be limited by inhibiting TF without affecting the proangiogenic capacity of the cells.

Detection of human papillomavirus DNA in bronchopulmonary carcinomas by hybrid capture II: a study of 185 tumors

BACKGROUND

Some human papillomaviruses (HPVs) are oncogenic in the cervix and are also associated with benign and malignant proliferations in other organs. Currently, the association of HPV with tumors of the lower respiratory tract is not so clearly defined because the studies are difficult to compare; series of cases reported from different geographic regions have used frozen or formalin fixed samples and a variety of techniques of HPV detection.

METHODS

The authors studied the prevalence of HPV in a large series of 185 frozen bronchopulmonary tumor samples with a new solution hybridization technique, Hybrid Capture II assay. This test is largely applied in cervical pathology. Its sensitivity is very close to the sensitivity of PCR. It allows the detection of 18 mucosal HPV types, divided into 1 oncogenic and 1 nononcogenic group.

RESULTS

Oncogenic HPV DNA was detected by the Hybrid Capture II assay in 5 cases (2.7%) of 185 (3 males and 2 females). In the rare positive cases detected, the authors could not find any consistent morphologic changes classically associated with HPV infection in anogenital lesions, such as koilocytosis.

CONCLUSIONS

Oncogenic HPV DNA is detected in a small proportion of cases of bronchopulmonary carcinoma, and thus HPV infection appears to play a limited role in the tumorigenesis of most lung carcinomas.

Sequential overexpression of LRP and MRP but not P-gp 170 in VP16-selected A549 adenocarcinoma cells

Chemoresistance remains the major obstacle to successful therapy of lung cancer. In order to understand drug resistance mechanisms, the expression of three proteins involved in multidrug resistance (P-gp, MRP and LRP) was studied, using the non-small cell lung cancer (NSCLC) A549 cell line. In addition, 3 levels of resistance were obtained by continuous exposure of cells to etoposide (VP16), which led to a 22-fold increase of the resistance index. The wild-type A549 strongly expressed the LRP protein while MRP protein was found at a moderate level. Induction of resistance paralleled an increase of the expression of the mrp gene and a decrease of the lrp gene; the mdr1 gene was not expressed. Taken together, these results indicate that intrinsically resistant NSCLC cells exhibit a complex pattern of MDR proteins, still susceptible to evolve under treatment. Such a fact would have to be considered in clinical situations.