Delayed blockade of the kinin B1 receptor reduces renal inflammation and fibrosis in obstructive nephropathy

Renal fibrosis is the common histological feature of advanced glomerular and tubulointerstitial disease leading to end-stage renal disease (ESRD). However, specific antifibrotic therapies to slow down the evolution to ESRD are still absent. Because persistent inflammation is a key event in the development of fibrosis, we hypothesized that the proinflammatory kinin B1 receptor (B1R) could be such a new target. Here we show that, in the unilateral ureteral obstruction model of renal fibrosis, the B1R is overexpressed and that delayed treatment with an orally active nonpeptide B1R antagonist blocks macrophage infiltration, leading to a reversal of the level of renal fibrosis. In vivo bone marrow transplantation studies as well as in vitro studies on renal cells show that part of this antifibrotic mechanism of B1R blockade involves a direct effect on resident renal cells by inhibiting chemokine CCL2 and CCL7 expression. These findings suggest that blocking the B1R is a promising antifibrotic therapy.     

PECAM-1 expression and activity negatively regulate multiple platelet signaling pathways

Platelet endothelial cell adhesion molecule-1 (PECAM-1) inhibits platelet response to collagen and may also inhibit two other major platelet agonists ADP and thrombin although this has been less well explored. We hypothesized that the combined effect of inhibiting these three platelet activating pathways may act to significantly inhibit thrombus formation. We demonstrate a negative relationship between PECAM-1 surface expression and platelet response to cross-linked collagen related peptide (CRP-XL) and ADP, and an inhibitory effect of PECAM-1 clustering on platelet response to CRP-XL, ADP and thrombin. This combined inhibition of multiple signaling pathways results in a marked reduction in thrombus formation.     

The APPLe Study: A Randomized,Community-Based,Placebo-Controlled Trial of Azithromycin for the Prevention of Preterm Birth,with Meta-Analysis

Background

Premature birth is the major cause of perinatal mortality and morbidity in both high- and low-income countries. The causes of preterm labour are multiple but infection is important. We have previously described an unusually high incidence of preterm birth (20%) in an ultrasound-dated, rural, pregnant population in Southern Malawi with high burdens of infective morbidity. We have now studied the impact of routine prophylaxis with azithromycin as directly observed, single-dose therapy at two gestational windows to try to decrease the incidence of preterm birth.

Methods and Findings

We randomized 2,297 pregnant women attending three rural and one peri-urban health centres in Southern Malawi to a placebo-controlled trial of oral azithromycin (1 g) given at 16–24 and 28–32 wk gestation. Gestational age was determined by ultrasound before 24 wk. Women and their infants were followed up until 6 wk post delivery. The primary outcome was incidence of preterm delivery, defined as <37 wk. Secondary outcomes were mean gestational age at delivery, perinatal mortality, birthweight, maternal malaria, and anaemia. Analysis was by intention to treat. There were no significant differences in outcome between the azithromycin group (n = 1,096) and the placebo group (n = 1,087) in respect of preterm birth (16.8% versus 17.4%), odds ratio (OR) 0.96, 95% confidence interval (0.76–1.21); mean gestational age at delivery (38.5 versus 38.4 weeks), mean difference 0.16 (−0.08 to 0.40); mean birthweight (3.03 versus 2.99 kg), mean difference 0.04 (−0.005 to 0.08); perinatal deaths (4.3% versus 5.0%), OR 0.85 (0.53–1.38); or maternal malarial parasitaemia (11.5% versus 10.1%), OR 1.11 (0.84–1.49) and anaemia (44.1% versus 41.3%) at 28–32 weeks, OR 1.07 (0.88–1.30). Meta-analysis of the primary outcome results with seven other studies of routine antibiotic prophylaxis in pregnancy (>6,200 pregnancies) shows no effect on preterm birth (relative risk 1.02, 95% confidence interval 0.86–1.22).

Conclusions

This study provides no support for the use of antibiotics as routine prophylaxis to prevent preterm birth in high risk populations; prevention of preterm birth requires alternative strategies.

Trial registration

Current Controlled Trials ISRCTN84023116 Please see later in the article for the Editors'' Summary     

The cellular prion protein and its role in Alzheimer disease

The cellular prion protein (PrP^C) is a membrane-bound glycoprotein especially abundant in the central nervous system (CNS). The scrapie prion protein (PrP^Sc, also termed prions) is responsible of transmissible spongiform encephalopathies (TSE), a group of neurodegenerative diseases which affect humans and other mammal species, although the presence of PrP^C is needed for the establishment and further evolution of prions.The present work compares the expression and localization of PrP^C between healthy human brains and those suffering from Alzheimer disease (AD).In both situations we have observed a rostrocaudal decrease in the amount of PrP^C within the CNS, both by immunoblotting and immunohistochemistry techniques. PrP^C is higher expressed in our control brains than in AD cases. There was a neuronal loss and astogliosis in our AD cases. There was a tendency of a lesser expression of PrP^C in AD cases than in healthy ones. And in AD cases, the intensity of the expression of the unglycosylated band is higher than the di- and monoglycosylated bands.With regards to amyloid plaques, those present in AD cases were positively labeled for PrP^C, a result which is further supported by the presence of PrP^C in the amyloid plaques of a transgenic line of mice mimicking AD.The work was done according to Helsinki Declaration of 1975, and approved by the Ethics Committee of the Faculty of Medicine of the University of Navarre.Key words: cellular prion protein, Alzheimer disease, transgenic mice     

The influence of hydrological regimes on sex ratios and spatial segregation of the sexes in two dioecious riparian shrub species in northern Sweden

River management practices have altered the hydrological regimes of many rivers and also altered the availability of regeneration niches for riparian species. We investigated the impact of changed hydrological regimes on the sex ratios and the Spatial Segregation of the Sexes (SSS) in the dioecious species Salix myrsinifolia Salisb.–phylicifolia L. and S. lapponum L. by studying the free-flowing Vindel River and the regulated Ume River in northern Sweden. We surveyed sex ratios of these species in 12 river reaches on the Vindel River and in 17 reaches on the Ume River. In addition, we surveyed the sex and location above mean river stage of 1,002 individuals across both river systems to investigate the SSS of both species. Cuttings were collected from male and female individuals of S. myrsinifolia–phylicifolia from both rivers and subjected to four different water table regimes in a greenhouse experiment to investigate growth response between the sexes. We found an M/F sex ratio in both river systems similar to the regional norm of 0.62 for S. myrsinifolia–phylicifolia and of 0.42 for S. lapponum. We found no evidence of SSS in either the free-flowing Vindel River or the regulated Ume River. In the greenhouse experiment, hydrological regime had a significant effect on shoot and root dry weight and on root length. Significantly higher shoot dry weights were found in females than in males and significantly different shoot and root dry weights were found between cuttings taken from the two rivers. We concluded that changed hydrological regimes are likely to alter dimensions of the regeneration niche and therefore to influence sex ratios and SSS at an early successional stage, making it difficult to find clear spatial patterns once these species reach maturity and can be sexed.     

Climate change alters temporal dynamics of alpine soil microbial functioning and biogeochemical cycling via earlier snowmelt

Soil microbial communities regulate global biogeochemical cycles and respond rapidly to changing environmental conditions. However, understanding how soil microbial communities respond to climate change, and how this influences biogeochemical cycles, remains a major challenge. This is especially pertinent in alpine regions where climate change is taking place at double the rate of the global average, with large reductions in snow cover and earlier spring snowmelt expected as a consequence. Here, we show that spring snowmelt triggers an abrupt transition in the composition of soil microbial communities of alpine grassland that is closely linked to shifts in soil microbial functioning and biogeochemical pools and fluxes. Further, by experimentally manipulating snow cover we show that this abrupt seasonal transition in wide-ranging microbial and biogeochemical soil properties is advanced by earlier snowmelt. Preceding winter conditions did not change the processes that take place during snowmelt. Our findings emphasise the importance of seasonal dynamics for soil microbial communities and the biogeochemical cycles that they regulate. Moreover, our findings suggest that earlier spring snowmelt due to climate change will have far reaching consequences for microbial communities and nutrient cycling in these globally widespread alpine ecosystems.Subject terms: Metagenomics, Climate-change ecology, Microbial ecology, Biogeochemistry, Soil microbiology     

Efficient flow cytometric assay for platelet-leukocyte aggregates in whole blood using fluorescence signal triggering.

BACKGROUND: Platelet-leukocyte aggregates (PLAs) may be important in thrombotic and inflammatory disease states, but accurate assessment of PLA formation in vivo is hampered by the propensity for in vitro artefacts caused by sample manipulation. A whole blood flow cytometric assay for circulating PLAs, based on minimal sample manipulation, was thus developed. METHODS: Citrated whole blood was labeled with a RPE-CD45 MAb (leukocyte marker) and an FITC-CD42a (GPIX) MAb (platelet marker). The latter was used to avoid possible influences of platelet glycoprotein proteolysis by neutrophil-derived proteases. The samples were mildly fixed with 0.5% formaldehyde saline. The cytometer was triggered by RPE-CD45 fluorescence. Leukocyte subpopulations were separated according to their typical light scattering and CD45 expression. RESULTS: Minimal sample manipulation and mild sample fixation resulted in minor in vitro artefacts and good sample stability. Fluorescence triggering increased the efficiency of the flow cytometric analysis approximately 5-fold compared with triggering with light scatter, and allowed discrimination of leukocyte subpopulations. The majority of PLAs involved monocytes and neutrophils, rather than lymphocytes, both without and with in vitro stimulation by ADP or thrombin. A cocktail of blocking MAbs to CD62P, CD15, GPIIb/IIIa and the CD11b/CD18 complex had no effect on unstimulated samples, whilst totally inhibiting aggregation induced by 10(-5) M ADP, suggesting that the PLAs in unstimulated blood were preformed in vivo. CONCLUSIONS: This whole blood flow cytometric assay for PLAs is simple and efficient, and appears to reflect closely platelet-leukocyte aggregates in circulating blood in vivo.