The role of NF-κB and Smac/DIABLO proteins in the treatment response and survival of acute myeloid leukemia patients

IntroductionThe misbalance between a family of inhibitor of apoptosis proteins (IAP), regulated by the nuclear factor kappa B (NF-κB) and their natural antagonist second mitochondrial-derived activator of caspases/direct IAP binding protein with low pI (Smac/DIABLO) are important to biology of acute myeloid leukemia (AML).Material and methodsThe aim of the study was to assess NF-κB and Smac/DIABLO proteins expression in blasts of 109 newly diagnosed AML patients using the multicolor flow cytometry and evaluate their influence on AML patients outcome.ResultsExpression of NF-κB and of Smac/DIABLO proteins were found in 95% and 98% of the patients, respectively. A negative correlation between Smac/DIABLO and NF-κB was observed. Age < 60 years old as well as higher Smac/DIABLO expression were associated with a higher probability of complete response achievement in the multivariate analysis. Longer overall survival (OS) in the univariate and multivariate analyses was influenced by age < 60 years old, a favorable or intermediate-risk karyotype and high Smac/DIABLO expression. Additionally, in the survival analysis of the subgroups, the patients aged < 60 years old, with high Smac/DIABLO expression, lower NF-κB expression and < 50% of bone marrow blasts who were treated with standard treatment had better OS.ConclusionsLower NF-κB and higher Smac/DIABLO expression may influence AML patients outcome.     

Dilution of candidates: the case of iron-related genes in restless legs syndrome

Restless legs syndrome (RLS) is a common multifactorial disease. Some genetic risk factors have been identified. RLS susceptibility also has been related to iron. We therefore asked whether known iron-related genes are candidates for association with RLS and, vice versa, whether known RLS-associated loci influence iron parameters in serum. RLS/control samples (n=954/1814 in the discovery step, 735/736 in replication 1, and 736/735 in replication 2) were tested for association with SNPs located within 4 Mb intervals surrounding each gene from a list of 111 iron-related genes using a discovery threshold of P=5 × 10⁻⁴. Two population cohorts (KORA F3 and F4 with together n=3447) were tested for association of six known RLS loci with iron, ferritin, transferrin, transferrin-saturation, and soluble transferrin receptor. Results were negative. None of the candidate SNPs at the iron-related gene loci was confirmed significantly. An intronic SNP, rs2576036, of KATNAL2 at 18q21.1 was significant in the first (P=0.00085) but not in the second replication step (joint nominal P-value=0.044). Especially, rs1800652 (C282Y) in the HFE gene did not associate with RLS. Moreover, SNPs at the known RLS loci did not significantly affect serum iron parameters in the KORA cohorts. In conclusion, the correlation between RLS and iron parameters in serum may be weaker than assumed. Moreover, in a general power analysis, we show that genetic effects are diluted if they are transmitted via an intermediate trait to an end-phenotype. Sample size formulas are provided for small effect sizes.     

SDF‐1/CXCR4/CXCR7 is pivotal for vascular smooth muscle cell proliferation and chronic allograft vasculopathy

Chronic rejection remains a major obstacle in transplant medicine. Recent studies suggest a crucial role of the chemokine SDF‐1 on neointima formation after injury. Here, we investigate the potential therapeutic effect of inhibiting the SDF‐1/CXCR4/CXCR7 axis with an anti‐SDF‐1 Spiegelmer (NOX‐A12) on the development of chronic allograft vasculopathy. Heterotopic heart transplants from H‐2bm12 to B6 mice and aortic transplants from Balb/c to B6 were performed. Mice were treated with NOX‐A12. Control animals received a nonfunctional Spiegelmer (revNOX‐A12). Samples were retrieved at different time points and analysed by histology, RT‐PCR and proliferation assay. Blockade of SDF‐1 caused a significant decrease in neointima formation as measured by intima/media ratio (1.0 ± 0.1 vs. 1.8 ± 0.1, P < 0.001 AoTx; 0.35 ± 0.05 vs. 1.13 ± 0.27, P < 0.05 HTx). In vitro treatment of primary vascular smooth muscle cells with NOX‐A12 showed a significant reduction in proliferation (0.42 ± 0.04 vs. 0.24 ± 0.03, P < 0.05). TGF‐β, TNF‐α and IL‐6 levels were significantly reduced under SDF‐1 inhibition (3.42 ± 0.37 vs. 1.67 ± 0.33, P < 0.05; 2.18 ± 0.37 vs. 1.0 ± 0.39, P < 0.05; 2.18 ± 0.26 vs. 1.6 ± 0.1, P < 0.05). SDF‐1/CXCR4/CXCR7 plays a critical role in the development of chronic allograft vasculopathy (CAV). Therefore, pharmacological inhibition of SDF‐1 with NOX‐A12 may represent a therapeutic option to ameliorate chronic rejection changes.     

Increased pulmonary prostacyclin synthesis in rats with chronic hypoxic pulmonary hypertension

OBJECTIVE: The regulation of pulmonary prostacyclin synthesis is not completely understood. We tested the hypothesis that prostacyclin production is predominantly stimulated by hemodynamic factors, such as increased shear-stress, and is thus increased in rats with chronic hypoxic pulmonary hypertension. METHODS: To this end, we determined pulmonary prostacyclin synthase (PGIS) gene expression, circulating levels of the stable prostacyclin metabolite 6-keto prostaglandin F(1alpha) (6-keto-PGF(1alpha)), pulmonary endothelin (ET)-1 gene expression, and ET-1 plasma levels in rats exposed to 4 weeks of hypoxia (10% O(2)) in the presence or absence of either the nitric oxide (NO) donor molsidomine (MD, 15 mg/kg/day) or the ET-A receptor antagonist LU135252 (LU, 50 mg/kg/day). RESULTS: Right ventricular systolic pressure (RVSP), the cross-sectional medial vascular wall area of pulmonary arteries, and ET-1 production increased significantly during hypoxia. PGIS mRNA levels increased 1.7-fold, and 6-keto-PGF(1alpha) plasma levels rose from 8.2+/-0.8 to 12.2+/-2.2 ng/ml during hypoxia (each P<0.05 vs. normoxic controls). MD and LU reduced RVSP and pulmonary vascular remodeling similarly (each P<0.05 vs. hypoxia), but only MD inhibited pulmonary ET-1 formation (P<0.05 vs. hypoxia). Nevertheless, both drugs attenuated the increase in PGIS gene expression and plasma 6-keto-PGF(1alpha) levels (each P<0.05 vs. hypoxia). CONCLUSION: Our data suggest that prostacyclin production in hypertensive rat lungs is predominantly increased by hemodynamic factors while hypoxia, NO and ET-1 per are less important stimuli, and that this increase may serve as a compensatory mechanism to partially negate the hypoxia-induced elevation in pulmonary vascular tone.     

Rapid Response to Cyclosporin A and Favorable Renal Outcome in Nongenetic Versus Genetic Steroid–Resistant Nephrotic Syndrome

Background and objectives

Treatment of congenital nephrotic syndrome (CNS) and steroid–resistant nephrotic syndrome (SRNS) is demanding, and renal prognosis is poor. Numerous causative gene mutations have been identified in SRNS that affect the renal podocyte. In the era of high–throughput sequencing techniques, patients with nongenetic SRNS frequently escape the scientific interest. We here present the long-term data of the German CNS/SRNS Follow-Up Study, focusing on the response to cyclosporin A (CsA) in patients with nongenetic versus genetic disease.

Design, setting, participants, & measurements

Cross–sectional and longitudinal clinical data were collected from 231 patients with CNS/SRNS treated at eight university pediatric nephrology units with a median observation time of 113 months (interquartile range, 50–178). Genotyping was performed systematically in all patients.

Results

The overall mutation detection rate was high at 57% (97% in CNS and 41% in SRNS); 85% of all mutations were identified by the analysis of three single genes only (NPHS1, NPHS2, and WT1), accounting for 92% of all mutations in patients with CNS and 79% of all mutations in patients with SRNS. Remission of the disease in nongenetic SRNS was observed in 78% of patients after a median treatment period of 2.5 months; 82% of nongenetic patients responded within 6 months of therapy, and 98% of patients with nongenetic SRNS and CsA–induced complete remission (normalbuminemia and no proteinuria) maintained a normal renal function. Genetic SRNS, on the contrary, is associated with a high rate of ESRD in 66% of patients. Only 3% of patients with genetic SRNS experienced a complete remission and 16% of patients with genetic SRNS experienced a partial remission after CsA therapy.

Conclusions

The efficacy of CsA is high in nonhereditary SRNS, with an excellent prognosis of renal function in the large majority of patients. CsA should be given for a minimum period of 6 months in these patients with nongenetic SRNS. In genetic SRNS, response to CsA was low and restricted to exceptional patients.