Two types of circulating endothelial progenitor cells in patients receiving long term therapy by HMG-CoA reductase inhibitors

3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) are widely used to decrease cholesterol synthesis and are well established to reduce vascular diseases. Recently, it has been proposed that statins mobilize endothelial progenitor cells from bone marrow during the first four weeks, which could help to prevent vascular diseases. However, in humans there are few data concerning the long term effects of statin treatment on these endothelial progenitor cells. We investigated whether endothelial progenitor cells can be detected and characterized in patients receiving long term statin therapy. Mononuclear cells from patients receiving or not receiving statin therapy were assessed for progenitor cell content by flow cytometry and were cultured in specific conditions to determine the number and the type of progenitors. Our results showed there were significantly more CD34(+), CD34(+)/CD144(+) circulating progenitor cells in the statin(pos) group than in the statin(neg) group. In culture two types of endothelial progenitor cells were detected. Early endothelial progenitor cells gave colonies at day 5 comprising elongated cells whereas late endothelial progenitor cells generated cobblestone-like colonies with strong proliferation capacities. The number of circulating early endothelial progenitor cells was significantly higher in the statin(neg) group, while only late endothelial progenitor cells were detected in the statin(pos) group. Moreover, cells from cobblestones clearly had an endothelial phenotype CD31(+), VEGF-R2(+), CD34(+), CD146(+) in contrast to cells from colonies from early endothelial progenitor cells, which were VEGF-R2(low), CD34(-). These results strongly suggest that long term statin treatment specifically maintains late endothelial progenitor cells in circulation with a CD34(+)/CD144(+) phenotype.     

Percutaneous pedicle screw instrumentation for temporary internal bracing of nondisplaced bony Chance fractures

OBJECTIVE AND IMPORTANCE: Although many patients with unstable Chance fractures can heal in an external brace, others will require internal stabilization. Short-segment minimally invasive internal bracing of a Chance fracture offers the rigidity and patient compliance of internal bracing with minimal tissue disruption. This technique has not yet been described. CLINICAL PRESENTATION: A healthy 16-year-old female and 21-year-old male sustained classic nondisplaced Chance fractures. They were both neurologically intact. TECHNIQUE: An image-guided Jamshidi needle was used to percutaneously place K-wires to direct percutaneous pedicle screws. Freehand percutaneous passing of rods to connect the pedicle screw heads on each side created a short-segment construct. CONCLUSIONS: Minimally invasive internal bracing of nondisplaced bony Chance fractures is an option for selected neurologically intact patients unable to tolerate external bracing.     

Cost of dialysis in France

The provision of care for patients with end-stage chronic renal failure is an important medical and economic challenge for the Health Insurance. Previous studies have shown a lower cost for home dialysis. More recently, studies have confirmed identical short-term survival rates between haemodialysis and peritoneal dialysis. Notwithstanding, home dialysis techniques utilization remains weak in France. This work aims at: determining the average annual cost of dialysis, per patient and per technique of dialysis, and assessing the global annual cost of dialysis in France, from the Health Insurance perspective. Methodologically, this article provides a static estimation of the cost of dialysis. Costs related to co-morbidities of end-stage chronic renal failure have not been considered. Standard patient care schemes have been outlined by a multidisciplinary expert committee, for each dialysis technique, and have been valorised using publicly available data and tariffs recorded in 2005. Our result show that home dialysis techniques are the less costly, with an average annual cost per patient of 49.9, 49.7 and 50.0 k euro respectively for home haemodialysis, automated peritoneal dialysis, and continuous ambulatory peritoneal dialysis. Autodialysis, autonomous in-center haemodialysis and in-center haemodialysis respectively cost 59.5, 62.3 and 81.5 k euro per patient and per annum. The total 2005 cost of dialysis for the Health Insurance is estimated at 2.1 billion euro. Therefore, the development of alternative techniques to in-center haemodialysis, such as home dialysis or autonomous in-center haemodialysis, autodialysis being already well developed, could generate savings for the Health Insurance. From the patient's perspective, it could also allow the enlightened choice of the best customized technique, less guided by local offer than by medical or social criteria, as well as by the patient's own opinion.     

Delta DNMT3B variants regulate DNA methylation in a promoter-specific manner

DNA methyltransferase 3B (DNMT3B) is critical in de novo DNA methylation during development and tumorigenesis. We recently reported the identification of a DNMT3B subfamily, DeltaDNMT3B, which contains at least seven variants, resulting from alternative pre-mRNA splicing. DeltaDNMT3Bs are the predominant expression forms of DNMT3B in human lung cancer. A strong correlation was observed between the promoter methylation of RASSF1A gene but not p16 gene (both frequently inactivated by promoter methylation in lung cancer) and expression of DeltaDNMT3B4 in primary lung cancer, suggesting a role of DeltaDNMT3B in regulating promoter-specific methylation of common tumor suppressor genes in tumorigenesis. In this report, we provide first experimental evidence showing a direct involvement of DeltaDNMT3B4 in regulating RASSF1A promoter methylation in human lung cancer cells. Knockdown of DeltaDNMT3B4 expression by small interfering RNA resulted in a rapid demethylation of RASSF1A promoter and reexpression of RASSF1A mRNA but had no effect on p16 promoter in the lung cancer cells. Conversely, normal bronchial epithelial cells with stably transfected DeltaDNMT3B4 gained an increased DNA methylation in RASSF1A promoter but not p16 promoter. We conclude that promoter DNA methylation can be differentially regulated and DeltaDNMT3Bs are involved in regulation of such promoter-specific de novo DNA methylation.     

Drug sensitivity prediction by CpG island methylation profile in the NCI-60 cancer cell line panel

Aberrant promoter hypermethylation and associated gene silencing are epigenetic hallmarks of tumorigenesis. It has been suggested that aberrant DNA methylation can affect the sensitivity of cancers to antineoplastic agents by altering expression of genes critical to drug response. To study this issue, we used bisulfite PCR to assess DNA methylation of 32 promoter-associated CpG islands in human cancer cell lines from the National Cancer Institute (NCI) drug-screening panel (NCI-60 panel). The frequency of aberrant hypermethylation of these islands ranged from 2% to 81% in NCI-60 cancer cells, and provided a database that can be analyzed for the sensitivity to approximately 30,000 drugs tested in this panel. By correlating drug activity with DNA methylation, we identified a list of methylation markers that predict sensitivity to chemotherapeutic drugs. Among them, hypermethylation of the p53 homologue p73 and associated gene silencing was strongly correlated with sensitivity to alkylating agents. We used small interfering RNA to down-regulate p73 expression in multiple cell lines, including the resistant cell lines TK10 (renal cancer) and SKMEL28 (melanoma). Down-regulating p73 substantially increased sensitivity to commonly used alkylating agents, including cisplatin, indicating that epigenetic silencing of p73 directly modulates drug sensitivity. Our results confirm that epigenetic profiles are useful in identifying molecular mediators for cancer drug sensitivity (pharmaco-epigenomics).     

The cytotoxicity of high-linear energy transfer radiation is reinforced by oxaliplatin in human glioblastoma cells

The combination of high-linear energy transfer (LET) radiation with chemotherapeutic agents may offer new perspectives in cancer treatment. We therefore assessed the consequences of a treatment in which U-87 human glioblastoma cells were irradiated with p(65)+Be neutrons in the presence of oxaliplatin, a third generation platinum anticancer drug having higher apoptosis-inducing activity than cisplatin. Cell survival, apoptosis, cell cycle progression as well as p21 and p53 protein expressions were analyzed. Results show that an enhanced cytotoxic effect was obtained when the two treatments were combined and that, unlike what we previously observed with cisplatin, this was not due to a reinforcement of apoptosis. Altogether, our results also indicate the potential of oxaliplatin for use in association with high-LET radiation against tumors refractory to conventional photon radiotherapy.