Arterial stiffness, isolated systolic hypertension, and cardiovascular risk in the elderly

Isolated systolic hypertension is an important cardiovascular risk factor in the elderly. In addition to systolic blood pressure, pulse pressure, pulse wave velocity, and carotid wave reflections are also strong cardiovascular risk factors in the elderly, as a consequence of the two main determinants of systolic hypertension: increased arterial stiffness and early wave reflections. Taken together, all these findings should help to optimize drug treatment, which has been shown to produce important but thus far insufficient beneficial effects on cardiovascular morbidity and mortality.     

Nephrogenic syndrome of inappropriate antidiuresis in adults: high phenotypic variability in men and women from a large pedigree

Nephrogenic syndrome of inappropriate antidiuresis (NSIAD) is a recently described genetic cause of hyponatremia in male infants. Whether this X-linked condition could be detected in the adult or also could affect women is unknown. A large five-generation family was identified in which the recently described arginine-vasopressin receptor type 2 (AVPR2) mutation that is responsible for NSIAD was segregated. The proband was a 74-yr-old patient who had a syndrome of inappropriate antidiuresis and whose hyponatremia resisted administration of two AVPR2 antagonists. The phenotype of family members who carry the mutation was investigated. Patients with normal serum sodium were subjected to a water-load test. The previously reported activating missense R137C mutation in the AVPR2 gene in three hemizygous male and four heterozygous female individuals was identified. Except in one woman, spontaneous episodes of hyponatremia or abnormal water-load test were identified in all patients with the mutation, whether male or female. Skewed X inactivation was evidenced in the blood of the asymptomatic woman, which is compatible with preferential inactivation of her mutated allele. NSIAD is not limited to male infants. The diagnosis also should be considered in both male and female adults.     

High molecular response rate of polycythemia vera patients treated with pegylated interferon alpha-2a

V617F JAK2 mutation is a reliable molecular marker of polycythemia vera (PV), potentially useful to monitor the effect of treatments in this disease. In a phase 2 study of pegylated (peg) IFN-alpha-2a in PV, we performed prospective sequential quantitative evaluation of the percentage of mutated JAK2 allele (%V617F) by real-time polymerase chain reaction (PCR). The %V617F decreased in 24 (89%) of 27 treated patients, from a mean of 49% to a mean of 27% (mean decrease of 44%; P < .001), and no evidence for a plateau was observed. In one patient, mutant JAK2 was no longer detectable after 12 months. In 3 patients homozygous for the mutation, reappearance of 50% of wild-type allele was observed during treatment. The results seem to confirm the hypothesis that IFN-alpha preferentially targets the malignant clone in PV and show that %V617F assessment using a quantitative method may provide the first tool to monitor minimal residual disease in PV. This trial was registered at www.clinicaltrials.gov as #NCT00241241.     

VIP reverses the expression profiling of TLR4-stimulated signaling pathway in rheumatoid arthritis synovial fibroblasts

Since recent evidences point out the potential involvement of Toll-like receptors (TLRs) in the therapeutic effect of vasoactive intestinal peptide (VIP), the purpose of this study is to elucidate the role of VIP as a negative regulator of TLR-signaling. To this aim, we analyzed in fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA) or osteoarthritis (OA), the expression profile of TLR-pathway related molecules, as well as the alterations induced by LPS stimulation in RA-FLS and the effect of VIP treatment. Cultured FLS were obtained from patients with RA or OA. RA-FLS were next stimulated with lipopolysaccharide (LPS) in presence or absence of VIP. The gene expression profiling of molecules involved in LPS-mediated TLR4-signaling was studied by cRNA microarray analysis. Twenty three molecules involved in TLR signaling resulted over-expressed at mRNA level in basal RA-FLS compared to OA-FLS. Moreover, in RA-FLS, 23 of the analyzed genes were found to be up-regulated by LPS stimulation whereas 30 were not affected. VIP down-regulated the LPS-induced RNA expression of molecules involved in TLR signaling pathway. Up-regulation of RNA expression of CD14, MD2, TRAM, TRIF, IRAK4, TAB2, TRAF6 and TBK1 was corroborated by RT-PCR as well as the VIP regulatory effect. Increased protein levels of TRAF6, TBK1 and pIRAK1 after exposure to LPS, and the inhibitory effect of VIP, were described by Western blotting. As functional consequences, it was observed the VIP-induced impaired production of IL-6 and RANTES/CCL5 after LPS stimulation. In conclusion, VIP acts as a negative modulator of the TLR4-signaling by overturning the production of several checkpoints molecules of the cascade and thus, widening its potential therapeutic effects.     

Long-term (up to 20 years) effects of 50-Hz magnetic field exposure on blood chemistry parameters in healthy men

ObjectivesThe potential effects of a chronic exposure to magnetic fields on blood chemistry in humanswere tested.DesignWe examined the nocturnal profiles and levels of the following blood parameters: electrolytes (sodium, potassium, chloride, calcium, magnesium, phosphorus), nonprotein nitrogenous compounds (uric acid, urea, creatinine), and glucose, in 15 men (38.0 ± 0.9 years) exposed chronically and daily for a period of 1 - 20 years, in the workplace and at home, to a 50-Hz magnetic field in search of any cumulative effect from those chronic conditions of exposure. The weekly geometric mean of individual exposures ranged from 0.1 to 2.6 μT. The results are compared to those obtained in our control group: 15 unexposed men of similar age (39.4 ± 1.2 years), with the same synchronization and physical activity that served as controls (individual exposures ranged from 0.004 to 0.092 μT). Blood samples were taken hourly from 20:00 h to 08:00 h.ResultsThis work shows that subjects exposed over a long period (up to 20 years) and on a daily basis to magnetic fields experienced significant changes in serum sodium, chloride, phosphorus and glucose where an effect for field-hour interaction was noted for exposures greater than 0.3 μT.ConclusionOur data suggest that long-term exposure to 50-Hzmagnetic fields (exposure > 0.3 μT) in healthy men could induce some biological modifications of certain blood parameters, though their clinical relevance needs further investigation.     

Proprotein convertase substilisin/kexin type 9 antagonism reduces low-density lipoprotein cholesterol in statin-treated hypercholesterolemic nonhuman primates

Proprotein convertase substilisin/kexin type 9 (PCSK9) promotes the degradation of low-density lipoprotein (LDL) receptor (LDLR) and thereby increases serum LDL-cholesterol (LDL-C). We have developed a humanized monoclonal antibody that recognizes the LDLR binding domain of PCSK9. This antibody, J16, and its precursor mouse antibody, J10, potently inhibit PCSK9 binding to the LDLR extracellular domain and PCSK9-mediated down-regulation of LDLR in vitro. In vivo, J10 effectively reduces serum cholesterol in C57BL/6 mice fed normal chow. J16 reduces LDL-C in healthy and diet-induced hypercholesterolemic cynomologous monkeys, but does not significantly affect high-density lipoprotein-cholesterol. Furthermore, J16 greatly lowered LDL-C in hypercholesterolemic monkeys treated with the HMG-CoA reductase inhibitor simvastatin. Our data demonstrate that anti-PCSK9 antibody is a promising LDL-C-lowering agent that is both efficacious and potentially additive to current therapies.     

Label-free epitope binning assays of monoclonal antibodies enable the identification of antigen heterogeneity

Label-free biosensors are often used in the discovery of therapeutic antibodies to characterize the epitope binding regions of a panel of monoclonal antibodies that target a specific antigen, thus facilitating their organization into epitope groups or "bins". When tested in a pairwise combinatorial manner, two antibodies that compete with one another for binding to a specific antigen may be grouped into the same epitope bin - that is, they recognize similar or overlapping epitopes - whereas two antibodies that bind simultaneously to the antigen are placed into different epitope bins. However, depending on the assay format used, results from such experiments can sometimes contradict one another. Here, we provide two examples that illustrate how antigen heterogeneity, either inherent in an antigen sample, or induced by the assay conditions, can confound the interpretation of epitope binning results and, in some cases, lead to erroneous conclusions. We highlight why assays that employ solution antigen are often more reliable than those that employ immobilized antigen and, by corroborating our binning results with assays that utilize native antigen, we determine which subpopulations of our heterogeneous antigen samples are biologically relevant and thus improve the correlation between epitope bins and functional activity. Furthermore, we provide recommendations for performing definitive binning assays and a diagnostic assay procedure that can be followed when antigen heterogeneity is suspected.