Preventive study in subjects at risk of fatal familial insomnia: Innovative approach to rare diseases

The text describes a preventive clinical trial with drug treatment in a very rare neurodegenerative disease (Fatal familial Insomnia, FFI) designed with the help of individuals at genetic risk of developing the disease, asymptomatic carriers, who have agreed to be exposed over a 10-year period to doxycycline, an antibiotic with anti-prion activity. At least 10 carriers of the FFI mutation over 42 y old will be treated with doxycycline (100 mg/die) and the incidence of the disease will be compared to that of an historical dataset. For ethical reasons a randomized, double-blind, placebo-controlled trial was not feasible, however the study design and the statistical analysis ensure the scientific value of the results. This approach might represent an important breakthrough in terms of potential therapy and knowledge of rare diseases that could give some hopes to these neglected patients.     

In vivo functions of mitogen-activated protein kinases: conclusions from knock-in and knock-out mice

Multicellular organisms achieve intercellular communication by means of signalling molecules whose effect on the target cell is mediated by signal transduction pathways. Such pathways relay, amplify and integrate signals to elicit appropriate biological responses. Protein kinases form crucial intermediate components of numerous signalling pathways. One group of protein kinases, the mitogen-activated protein kinases (MAP kinases) are kinases involved in signalling pathways that respond primarily to mitogens and stress stimuli. In vitro studies revealed that the MAP kinases are implicated in several cellular processes, including cell division, differentiation, cell survival/apoptosis, gene expression, motility and metabolism. As such, dysfunction of specific MAP kinases is associated with diseases such as cancer and immunological disorders. However, the genuine in vivo functions of many MAP kinases remain elusive. Genetically modified mouse models deficient in a specific MAP kinase or expressing a constitutive active or a dominant negative variant of a particular MAP kinase offer valuable tools for elucidating the biological role of these protein kinases. In this review, we focus on the current status of MAP kinase knock-in and knock-out mouse models and their phenotypes. Moreover, examples of the application of MAP kinase transgenic mice for validating therapeutic properties of specific MAP kinase inhibitors, and for investigating the role of MAP kinase in pathogen-host interactions will be discussed.     

Photochemistry and DNA-affinity of some pyrimidine-substituted styryl-azinium iodides

The relaxation properties of the excited states of three iodides of trans-1,2-diarylethene analogues (where one aryl group is a methylpyridinium, methylquinolinium or dimethylimidazolium group and the other one is a phenyl ring para-substituted by a pyrimidine ring) have been investigated in buffered (pH = 7) aqueous solution. As found in previous works for several analogues, these quaternized salts undergo efficient trans→cis photoisomerization while the yield of the radiative deactivation is very small at room temperature. The solvent effect on the spectral behaviour indicates the occurrence of intramolecular charge transfer which can induce interesting non-linear optical properties. The results of a study of the interactions of these salts with DNA, which might affect the cell metabolism, showed a relatively modest binding affinity for the pyridinium and imidazolium salts and a more substantial affinity for the quinolinium analogue. The formation of ligand-DNA complexes affects only slightly the radiative relaxation yield while leading to a relevant reduction of the isomerization yield. Measurements of the linear dichroism behaviour of the three compounds and comparison with three analogues bearing furan or thienyl groups, which have been found to display different affinity with DNA in previous works, gave interesting information on the nature of the ligand-DNA binding of these compounds.     

Role of IL-6 and CD23 in the resistance to growth arrest and apoptosis in LCL41 B lymphoma cells

Interleukin-6 (IL-6) is a growth and survival factor in Epstein-Barr virus (EBV)-infected B lymphoma cells and IL-6 antagonists have been used in clinical practice for this pathology. We thus wanted to investigate the effect of the IL-6 receptor antagonist Sant7 on proliferative and anti-apoptotic signals in the IL-6-secreting LCL41 B lymphoid cells, taken from a patient with EBV-induced lymphoproliferative disorder. Results show efficient inhibition of constitutive Stat3 activation by Sant7. However, this inhibition is associated with marginal induction of apoptosis and with minor decrease of cell proliferation, contrary to the effect of the Jak kinase inhibitor AG490, which down-regulates both proliferation and Stat3 activation. Anti-apoptotic markers such as Bcl-xL or Mcl-1 are constitutively expressed in these cells, and their expression is not affected by Sant7 treatment. Inhibition of Stat3 activation is therefore not sufficient to prevent proliferation and to induce apoptosis in these cells. In addition, low cell density is a condition favouring inhibition of cell clustering and anti-proliferative Sant7 activity. A marked inhibition of cell cluster formation and proliferation is achieved by antibody treatment against the CD23 mature B cell surface marker expressed in LCL41 cells. These findings may thus contribute to the identification of possible resistance mechanisms to growth arrest in B cell lymphoproliferative conditions.     

Analytical precision,biological variation,and mathematical normalization in high data density metabolomics

Metabolic serotypes sensitive to caloric intake may enable sera metabolomic profiles to validate epidemiological parameters and predict disease risk in humans. This long-range goal is complicated by the lack of known state markers and the requirement for simultaneous monitoring of multiple small changes. Therefore, analytical precision for appropriate high data density studies using HPLC separations coupled with coulometric array detectors was evaluated over a two month period in pooled rat sera samples (previously collected and stored at –80 °C), and in authentic biochemical standards. In sera, mean coefficients of variation (CV) of retention time and ratio accuracy within the established metabolic serotype varied within ±1% and ±3%, respectively. In sets of purified standards, the same parameters fluctuated, correspondently, in ranges of ±0.1% and ±1%. Median CV of the metabolite concentrations were ~13% in standards and ~11–19% in sera, and varied non-monotonically with the analytical system status and experimental design. These parameters were shown to be sufficiently controlled so as not to dominate intra-group biological variability in serum metabolomics studies. Continuation of experimental runs across an analytical breakpoint (column replacement) was associated with disproportionate changes in metabolite concentrations, independent of maintained analytical precision. These changes were sufficient to shift overall profile localization in megavariate projection analyses. We developed a mathematical approach to normalize this break and use partial least squares projection to latent structure discriminant analysis to confirm validity of this normalization approach. This generally applicable mathematical correction helps enable longer term high data density studies by removing a critical source of systemic variation.     

Anaerobic and aerobic relative contribution to total energy release during supramaximal effort in patients with left ventricular dysfunction.

Energetic metabolism during effort is impaired in patients with left ventricular dysfunction (Dysf), but data have been lacking up to now on the relative anaerobic vs. aerobic contribution to total energy release during supramaximal effort. Recently, the maximal accumulated oxygen deficit (MAOD) has been shown to be measurable in Dysf patients, making it possible to evaluate the anaerobic/aerobic interaction under conditions of maximal stress of both anaerobic and aerobic metabolic pathways in this population. Nineteen Dysf patients and 17 normal patients (N) underwent one ramp cardiopulmonary, three moderate-intensity constant-power, and three supramaximal constant-power (1- to 2-min, 2- to 3-min, and 3- to 4-min duration) exercise tests. MAOD was the difference between accumulated O(2) demand (accO(2)dem; estimated from the moderate-intensity O(2) uptake/watt relationship) and uptake during supramaximal tests. Percent anaerobic (%Anaer) and aerobic (%Aer) energetic release were [(MAOD/accO(2)dem).100] and 100 - %Anaer, respectively. MAOD did not vary between 1-2, 2-3, and 3-4 min supramaximal tests, whereas accO(2)dem increased significantly with and was linearly related to test duration in both Dysf and N. Consequently, %Anaer and %Aer decreased and increased, respectively, with increasing test duration but did not differ between Dysf and N in 1-2 min, 2-3 min, and 3-4 min tests. Our study demonstrates a similar relative anaerobic vs. aerobic contribution to total energy release during supramaximal effort in Dysf and N. This finding indicates that energetic metabolism during supramaximal exercise is exercise tolerance independent and that relative anaerobic vs. aerobic contribution in this effort domain remains the same within the physiology- or pathology-induced limits to individual peak exercise performance.     

Circulating hematopoietic progenitor cells in runners.

Because endurance exercise causes release of mediators and growth factors active on the bone marrow, we asked whether it might affect circulating hematopoietic progenitor cells (HPCs) in amateur runners [n = 16, age: 41.8 +/- 13.5 (SD) yr, training: 93.8 +/- 31.8 km/wk] compared with sedentary controls (n = 9, age: 39.4 +/- 10.2 yr). HPCs, plasma cortisol, interleukin (IL)-6, granulocyte colony-stimulating factor (G-CSF), and the growth factor fms-like tyrosine kinase-3 (flt3)-ligand were measured at rest and after a marathon (M; n = 8) or half-marathon (HM; n = 8). Circulating HPC counts (i.e., CD34(+) cells and their subpopulations) were three- to fourfold higher in runners than in controls at baseline. They were unaffected by HM or M acutely but decreased the morning postrace. Baseline cortisol, flt3-ligand, IL-6, and G-CSF levels were similar in runners and controls. IL-6 and G-CSF increased to higher levels after M compared with HM, whereas cortisol and flt3-ligand increased similarly postrace. Our data suggest that increased HPCs reflect an adaptation response to recurrent, exercise-associated release of neutrophils and stress and inflammatory mediators, indicating modulation of bone marrow activity by habitual running.     

In vivo effects of dexamethasone on blood gene expression in ataxia telangiectasia

The effect of estrogens is mediated by activation of estrogen receptors (ERs). Because ER-α gene polymorphisms may exert different effects in childhood, we analyzed the associations between the IVS1 ?397T>C (PvuII) polymorphism and systemic inflammatory state, proangiogenic factors, frequency of monocyte subsets, lipid profile, blood pressure, and vascular complications in girls with type 1 diabetes mellitus (DM1). We examined 180 young girls with DM1 and 120 healthy age-matched controls. The analysis concerned PvuII polymorphism of the ER-α gene as well as the levels of serum inflammatory markers (CRP, IL-6, TNF-α), proangiogenic factors (VEGF, angiogenin), 17β-estradiol, values of monocyte subsets (CD14⁺⁺CD16^? and CD14⁺CD16⁺), lipid profile, and blood pressure. In our study, girls with CC genotype had lower level of inflammatory and angiogenic factors and lower frequencies of CD14⁺CD16⁺ monocytes in comparison to CT or TT carriers. Simultaneously, the CC carriers had a greater population of CD14⁺⁺CD16^? monocytes, increased blood pressure, and serum levels of: estrogen, total cholesterol, triglycerides, and low-density lipoprotein cholesterol than girls bearing CT or TT genotype. Our study suggests a pleiotropic effect of PvuII polymorphic CC variant on diabetic vasculopathies. Although the CC genotype carriers demonstrate less inflammatory and angiogenic activity, they seem to display less favorable cardiometabolic features. Based on our study, we cannot distinguish PvuII ER-α genotype that could be useful in identification of DM1 girls that are more prone to develop of late vascular complications, before the occurrence of first clinical symptoms.