Effect of paricalcitol and calcitriol on aortic wall remodeling in uninephrectomized ApoE knockout mice

Despite an only minor reduction in the glomerular filtration rate, uninephrectomy (UNX) markedly accelerates the rate of growth of atherosclerotic plaques in ApoE-/- mice. It has been suggested that vitamin D receptor (VDR) activation exerts an antiproliferative effect on vascular smooth muscle cells, but the side effects may limit its use. To assess a potentially different spectrum of actions, we compared the effects of paricalcitol and calcitriol on remodeling and calcification of the aortic wall in sham-operated and UNX ApoE-/- mice on a diet with normal cholesterol content. Sham-operated and UNX mice were randomly allotted to treatment with solvent, calcitriol (0.03 μg/kg) or paricalcitol (0.1 μg/kg) 5 times/wk intraperitoneally for 10 wk. Semithin (0.6 μm) sections of the aorta were analyzed by 1) morphometry, 2) immunohistochemistry, and 3) Western blotting of key proteins involved in vascular calcification and growth. Compared with sham-operated animals (5.6 ± 0.24), the wall-to-lumen ratio (x100) of the aorta was significantly higher in solvent- and calcitriol-treated UNX animals (6.64 ± 0.27 and 7.17 ± 0.81, respectively, P < 0.05), but not in paricalcitol-treated UNX (6.1 5 ± 0.32). Similar differences were seen with respect to maximal plaque height. Expression of transforming growth factor (TGF)-β1 in aortic intima/plaque was also significantly higher in UNX solvent and UNX calcitriol compared with sham-operated and UNX paricalcitol animals. Treatment with both paricalcitol and calcitriol caused significant elevation of VDR expression in the aorta. While at the dose employed paricalcitol significantly reduced TGF-β expression in plaques, calcitriol in contrast caused significant vascular calcification and elevated expression of related proteins (BMP2, RANKL, and Runx2).     

High-dose enalapril treatment reverses myocardial fibrosis in experimental uremic cardiomyopathy

Aims

Patients with renal failure develop cardiovascular alterations which contribute to the higher rate of cardiac death. Blockade of the renin angiotensin system ameliorates the development of such changes. It is unclear, however, to what extent ACE-inhibitors can also reverse existing cardiovascular alterations. Therefore, we investigated the effect of high dose enalapril treatment on these alterations.

Methods

Male Sprague Dawley rats underwent subtotal nephrectomy (SNX, n = 34) or sham operation (sham, n = 39). Eight weeks after surgery, rats were sacrificed or allocated to treatment with either high-dose enalapril, combination of furosemide/dihydralazine or solvent for 4 weeks. Heart and aorta were evaluated using morphometry, stereological techniques and TaqMan PCR.

Results

After 8 and 12 weeks systolic blood pressure, albumin excretion, and left ventricular weight were significantly higher in untreated SNX compared to sham. Twelve weeks after SNX a significantly higher volume density of cardiac interstitial tissue (2.57±0.43% in SNX vs 1.50±0.43% in sham, p<0.05) and a significantly lower capillary length density (4532±355 mm/mm³ in SNX vs 5023±624 mm/mm³ in sham, p<0.05) were found. Treatment of SNX with enalapril from week 8–12 significantly improved myocardial fibrosis (1.63±0.25%, p<0.05), but not capillary reduction (3908±486 mm/mm³) or increased intercapillary distance. In contrast, alternative antihypertensive treatment showed no such effect. Significantly increased media thickness together with decreased vascular smooth muscles cell number and a disarray of elastic fibres were found in the aorta of SNX animals compared to sham. Both antihypertensive treatments failed to cause complete regression of these alterations.

Conclusions

The study indicates that high dose ACE-I treatment causes partial, but not complete, reversal of cardiovascular changes in SNX.     

Vectors based on modified vaccinia Ankara expressing influenza H5N1 hemagglutinin induce substantial cross-clade protective immunity

Background

New highly pathogenic H5N1 influenza viruses are continuing to evolve with a potential threat for an influenza pandemic. So far, the H5N1 influenza viruses have not widely circulated in humans and therefore constitute a high risk for the non immune population. The aim of this study was to evaluate the cross-protective potential of the hemagglutinins of five H5N1 strains of divergent clades using a live attenuated modified vaccinia Ankara (MVA) vector vaccine.

Methodology/Principal Findings

The replication-deficient MVA virus was used to express influenza hemagglutinin (HA) proteins. Specifically, recombinant MVA viruses expressing the HA genes of the clade 1 virus A/Vietnam/1203/2004 (VN/1203), the clade 2.1.3 virus A/Indonesia/5/2005 (IN5/05), the clade 2.2 viruses A/turkey/Turkey/1/2005 (TT01/05) and A/chicken/Egypt/3/2006 (CE/06), and the clade 2.3.4 virus A/Anhui/1/2005 (AH1/05) were constructed. These experimental live vaccines were assessed in a lethal mouse model. Mice vaccinated with the VN/1203 hemagglutinin-expressing MVA induced excellent protection against all the above mentioned clades. Also mice vaccinated with the IN5/05 HA expressing MVA induced substantial protection against homologous and heterologous AH1/05 challenge. After vaccination with the CE/06 HA expressing MVA, mice were fully protected against clade 2.2 challenge and partially protected against challenge of other clades. Mice vaccinated with AH1/05 HA expressing MVA vectors were only partially protected against homologous and heterologous challenge. The live vaccines induced substantial amounts of neutralizing antibodies, mainly directed against the homologous challenge virus, and high levels of HA-specific IFN-γ secreting CD4 and CD8 T-cells against epitopes conserved among the H5 clades and subclades.

Conclusions/Significance

The highest level of cross-protection was induced by the HA derived from the VN/1203 strain, suggesting that pandemic H5 vaccines utilizing MVA vector technology, should be based on the VN/1203 hemagglutinin. Furthermore, the recombinant MVA-HA-VN, as characterized in the present study, would be a promising candidate for such a vaccine.     

Menstrual Cycle Phase Modulates Emotional Conflict Processing in Women with and without Premenstrual Syndrome (PMS) – A Pilot Study

Background

Premenstrual syndrome (PMS) is characterized by a cluster of psychological and somatic symptoms during the late luteal phase of the menstrual cycle that disappear after the onset of menses. Behavioral differences in emotional and cognitive processing have been reported in women with PMS, and it is of particular interest whether PMS affects the parallel execution of emotional and cognitive processing. Related to this is the question of how the performance of women with PMS relates to stress levels compared to women without PMS. Cortisol has been shown to affect emotional processing in general and it has also been shown that women with severe PMS have a particular cortisol profile.

Methods

We measured performance in an emotional conflict task and stress levels in women with PMS (n = 15) and women without PMS (n = 15) throughout their menstrual cycle.

Results

We found a significant increase (p = 0.001) in the mean reaction time for resolving emotional conflict from the follicular to the luteal cycle phase in all subjects. Only women with PMS demonstrated an increase in physiological and subjective stress measures during the luteal menstrual cycle phase.

Conclusions

Our findings suggest that the menstrual cycle modulates the integration of emotional and cognitive processing in all women. Preliminary data are supportive of the secondary hypothesis that stress levels are mediated by the menstrual cycle phase only in women with PMS. The presented evidence for menstrual cycle-specific differences in integrating emotional and cognitive information highlights the importance of controlling for menstrual cycle phase in studies that aim to elucidate the interplay of emotion and cognition.     

Next-generation sequencing reveals how RNA catalysts evolve from random space

Catalytic RNAs are attractive objects for studying molecular evolution. To understand how RNA libraries can evolve from randomness toward highly active catalysts, we analyze the original samples that led to the discovery of Diels–Alderase ribozymes by next-generation sequencing. Known structure-activity relationships are used to correlate abundance with catalytic performance. We find that efficient catalysts arose not just from selection for reactivity among the members of the starting library, but from improvement of less potent precursors by mutations. We observe changes in the ribozyme population in response to increasing selection pressure. Surprisingly, even after many rounds of enrichment, the libraries are highly diverse, suggesting that potential catalysts are more abundant in random space than generally thought. To highlight the use of next-generation sequencing as a tool for in vitro selections, we also apply this technique to a recent, less characterized ribozyme selection. Making use of the correlation between sequence evolution and catalytic activity, we predict mutations that improve ribozyme activity and validate them biochemically. Our study reveals principles underlying ribozyme in vitro selections and provides guidelines to render future selections more efficient, as well as to predict the conservation of key structural elements, allowing the rational improvement of catalysts.