Search

Background and Objectives: Erythropoiesis-stimulating agents correct anemia of CKD but may increase cardiovascular risk. We compared cardiovascular outcomes and all-cause mortality associated with monthly methoxy polyethylene glycol-epoetin beta with those of the shorter-acting agents epoetin alfa/beta and darbepoetin alfa in patients with anemia of CKD., Design, Setting, Participants, & Measurements: We conducted a multicenter, open-label, noninferiority trial in which patients were randomized to receive methoxy polyethylene glycol-epoetin beta or reference erythropoiesis-stimulating agents, stratified by maintenance or correction treatment status and C-reactive protein level. The trial had a prespecified noninferiority margin of 1.20 for the hazard ratio (HR) for the primary end point (a composite of all-cause mortality, nonfatal myocardial infarction or stroke, adjudicated by an independent blinded committee). This trial is registered with ClinicalTrials.gov, number NCT00773513., Results: In total, 2818 patients underwent randomization, received methoxy polyethylene glycol-epoetin beta or a reference agent, and were followed for a median of 3.4 years (maximum, 8.4 years). In the modified intention-to-treat analysis, a primary end point event occurred in 640 (45.4%) patients in the methoxy polyethylene glycol-epoetin beta arm, and 644 (45.7%) in the reference arm (HR 1.03; 95% confidence interval [95% CI], 0.93 to 1.15, P =0.004 for noninferiority). All-cause mortality was not different between treatment groups (HR 1.06; 95% CI, 0.94 to 1.19). Results in patient subgroups on dialysis or treated in the correction or maintenance settings were comparable to the primary analysis., Conclusions: In patients with anemia of CKD, once-monthly methoxy polyethylene glycol-epoetin beta was noninferior to conventional, shorter-acting erythropoiesis-stimulating agents with respect to rates of major adverse cardiovascular events or all-cause mortality., (Copyright © 2019 by the American Society of Nephrology.)

Expression of isolated beta integrin cytoplasmic domains in cultured endothelial cells was reported to induce cell detachment and death. To test whether cell death was the cause or the consequence of cell detachment, we expressed isolated integrin beta1 cytoplasmic and transmembrane domains (CH1) in cultured human umbilical vein endothelial cells (HUVEC), and monitored detachment, viability, caspase activation and signaling. CH1 expression induced dose-dependent cell detachment. At 24 h over 90% of CH1-expressing HUVEC were detached but largely viable (>85%). No evidence of pro-caspase-8,-3, and PARP cleavage or suppression of phosphorylation of ERK, PKB and Ikappa-B was observed. The caspase inhibitor z-VAD did not prevent cell detachment. At 48 h, however, CH1-expressing cells were over 50% dead. As a comparison trypsin-mediated detachment resulted in a time-dependent cell death, paralleled by caspase-3 activation and suppression of ERK, PKB and Ikappa-B phosphoyrylation at 24 h or later after detachment. HUVEC stimulation with agents that strengthen integrin-mediated adhesion (i.e. PMA, the Src inhibitor PP2 and COMP-Ang1) did not prevent CH1-induced detachment. Expression of CH1 in rat carotid artery endothelial cells in vivo caused endothelial cell detachment and increased nuclear DNA fragmentation among detached cells. A construct lacking the integrin cytoplasmic domain (CH2) had no effect on adhesion and cell viability in vitro and in vivo. These results demonstrate that isolated beta1 cytoplasmic domain expression induces caspase-independent detachment of viable endothelial cells and that death is secondary to detachment (i.e. anoikis). They also reveal an essential role for integrins in the adhesion and survival of quiescent endothelial cells in vivo.

The p53 gene is frequently mutated in human tumors; in hepatocellular carcinomas, there is a high frequency of a specific mutation at codon 249 in regions with significant aflatoxin exposure. To assess the role of this p53 mutation in the development of hepatocellular carcinoma, a mutant murine p53 gene, p53ser246, which corresponds to human codon 249, was transfected into a differentiated, nontransformed hepatocyte cell line AML12. Expression of p53ser246 in this line resulted in a growth advantage when compared with either a control vector (which contains a large p53 deletion) or with a different p53 mutant, val135, not found in hepatocellular carcinoma. Overall, there was a threefold increase in colony formation after transfection with p53ser246 as compared with the control or p53val135 vectors, and the p53ser246 plates developed consistently larger colonies. Whereas clones expressing the control or p53val135 constructs showed no significant morphological changes, clones expressing p53ser246 showed increased heterogeneity (large multinucleated cells and areas of small crowded cells) without focus formation. In addition, the ser246 mutation imparted a growth advantage in serum-free media, suggesting less dependence on specific factors present in serum. None of the mutant p53 or control lines were capable of growth in soft agar or tumor formation in nude mice. Thus in this model, in which endogenous wild-type p53 expression is retained, a high level of mutant p53 expression is not sufficient to transform hepatocytes. Our findings indicate that p53ser246 has effects on hepatocytes that may result in a clonal growth advantage and suggest that additional factors are required for the development of hepatocellular carcinoma.

Changes of the number and properties of the epidermal growth factor (EGF) receptor occur during liver regeneration and may be of importance in the maintenance of hepatocellular mass in liver cirrhosis. We therefore studied the changes in the number and distribution of EGF receptor in the development of liver cirrhosis induced by bile duct ligation. Receptor binding assays demonstrated a marked decrease in the binding capacity of crude plasma membrane fractions from 45 +/- SD 16 to 19 +/- 10 fmol/mg protein (p < 0.001) in control and bile duct ligated livers, respectively while the Kd increased after 3 days of bile duct ligation from 0.5 +/- 0.2 to 1.4 +/- 0.6 nmol/l. Total receptor concentration in the same membrane fractions, as assessed by Western blot analysis, was not changed. The expression of EGF receptor mRNA was reduced to about one third of control levels after 28 days of bile obstruction. Immunohistochemistry, performed using monoclonal antibodies against EGF receptor, showed a strong labeling of cytoplasm (87 +/- 3% positive) and plasma membranes (84 +/- 24%) but no labeling of nuclei in control livers. In bile duct ligated rats, in contrast, cytoplasmic staining was decreased (15 +/- 12%) already after 3 days of bile obstruction; labeling of canalicular membranes and nuclei appeared after 14 days. The shift of EGF receptor from plasma membranes to nuclei supports the notion that EGF receptor is involved in the maintenance of hepatocellular mass in this model of liver cirrhosis. This concept is supported by the finding of decreased mRNA for EGF receptor presumably representing down-regulation as seen in regenerating rat liver.