The human placenta as a target tissue for glucagon

Glucagon's effect on the placenta was studied in cultured human term trophoblast and in homogenized term and first-trimester placentas. In studies with cultured term trophoblast, glucagon stimulated the generation of cyclic AMP and estradiol secretion and inhibited placental lactogen secretion. Incubation of homogenates of term and of first-trimester placenta with 0.5 mM dibutyryl cAMP revealed a marked decrease of pyruvate kinase activity. Glucagon produced a similar decrease in first-trimester homogenates, but failed to affect term placentas. The present demonstration of the placenta as a target tissue for glucagon suggests an active contribution of the trophoblast to energy metabolism during pregnancy.     

Nitric oxide and polyamine pathway-dependent modulation of neutrophil free amino- and α-keto acid profiles or host defense capability

Summary. We have examined the effects of N_ω-nitro-L-arginine-methylester-hydrochloride [L-NAME; inhibitor of nitric oxide synthase], S-nitroso-N-acetyl-penicillamine [SNAP; nitric oxide donor], α-difluoro-methyl-ornithine [DFMO; inhibitor of ornithine decarboxylase] arginine or ornithine as well as the combination of arginine or ornithine with L-NAME, SNAP or DFMO on intracellular free amino- and α-keto acid profiles and the immune function markers superoxide anion and hydrogen peroxide generation as well as released myeloperoxidase activity in neutrophils (PMN). Although the underlying mechanisms still remain unclear, we believe from our results that nitric oxide as well as polyamine-dependent pathways are involved in the signal transmission of free radical molecule, beneficial nutritional therapy or maleficient pharmacological stress-induced alterations in PMN nutrient composition. Relevant changes in intragranulocyte free amino- and α-keto acid homeostasis and metabolism, especially, may be one of the determinants in PMN nutrition that positively or negatively influences and modulate neutrophil host defence capability and immunocompetence.     

Endothelial Semaphorin 3fb regulates Vegf pathway-mediated angiogenic sprouting

Vessel growth integrates diverse extrinsic signals with intrinsic signaling cascades to coordinate cell migration and sprouting morphogenesis. The pro-angiogenic effects of Vascular Endothelial Growth Factor (VEGF) are carefully controlled during sprouting to generate an efficiently patterned vascular network. We identify crosstalk between VEGF signaling and that of the secreted ligand Semaphorin 3fb (Sema3fb), one of two zebrafish paralogs of mammalian Sema3F. The sema3fb gene is expressed by endothelial cells in actively sprouting vessels. Loss of sema3fb results in abnormally wide and stunted intersegmental vessel artery sprouts. Although the sprouts initiate at the correct developmental time, they have a reduced migration speed. These sprouts have persistent filopodia and abnormally spaced nuclei suggesting dysregulated control of actin assembly. sema3fb mutants show simultaneously higher expression of pro-angiogenic (VEGF receptor 2 (vegfr2) and delta-like 4 (dll4)) and anti-angiogenic (soluble VEGF receptor 1 (svegfr1)/ soluble Fms Related Receptor Tyrosine Kinase 1 (sflt1)) pathway components. We show increased phospho-ERK staining in migrating angioblasts, consistent with enhanced Vegf activity. Reducing Vegfr2 kinase activity in sema3fb mutants rescues angiogenic sprouting. Our data suggest that Sema3fb plays a critical role in promoting endothelial sprouting through modulating the VEGF signaling pathway, acting as an autocrine cue that modulates intrinsic growth factor signaling.     

Unexpected AChE inhibitory activity of (2E)α,β-unsaturated fatty acids

A small library of (E) α,β-unsaturated fatty acids was prepared, and 20 different saturated and mono-unsaturated fatty acids differing in chain length were subjected to Ellman’s assays to determine their ability to act as inhibitors for AChE or BChE. While the compounds were only very weak inhibitors of BChE, seven molecules were inhibitors of AChE holding IC₅₀?=?4.3–12.8?M with three of them as significant inhibitors of this enzyme. The results have shown trans 2-mono-unsaturated fatty acids are better inhibitors for AChE than their saturated analogs. Furthermore, the screening results indicate that the chain length is crucial for obtaining an inhibitory efficacy. The best results were obtained for (2E) eicosenoic acid (14) showing inhibition constants K_i?=?1.51?±?0.09?M and K_i′?=?7.15?±?0.55?M. All tested compounds were mixed-type inhibitors with a dominating competitive part. Molecular modelling calculations indicate a different binding mode of active/inactive compounds for the enzymes AChE and BChE.     

The association between cardiovascular disease gene mutations and recurrent pregnancy loss in the Lebanese population

Molecular Biology Reports - Recurrent pregnancy loss (RPL) is a problem affecting up to 5% of women of childbearing age due to many factors. Studies have shown that RPL and cardiovascular disease...     

Pioglitazone Improves Fat Distribution,the Adipokine Profile and Hepatic Insulin Sensitivity in Non-Diabetic End-Stage Renal Disease Subjects on Maintenance Dialysis: A Randomized Cross-Over Pilot Study

Background

Fat redistribution, increased inflammation and insulin resistance are prevalent in non-diabetic subjects treated with maintenance dialysis. The aim of this study was to test whether pioglitazone, a powerful insulin sensitizer, alters body fat distribution and adipokine secretion in these subjects and whether it is associated with improved insulin sensitivity.

Trial Design

This was a double blind cross-over study with 16 weeks of pioglitazone 45 mg vs placebo involving 12 subjects.

Methods

At the end of each phase, body composition (anthropometric measurements, dual energy X-ray absorptometry (DEXA), abdominal CT), hepatic and muscle insulin sensitivity (2-step hyperinsulinemic euglycemic clamp with 2H2-glucose) were measured and fasting blood adipokines and cardiometabolic risk markers were monitored.

Results

Four months treatment with pioglitazone had no effect on total body weight or total fat but decreased the visceral/sub-cutaneous adipose tissue ratio by 16% and decreased the leptin/adiponectin (L/A) ratio from 3.63×10⁻³ to 0.76×10⁻³. This was associated with a 20% increase in hepatic insulin sensitivity without changes in muscle insulin sensitivity, a 12% increase in HDL cholesterol and a 50% decrease in CRP.

Conclusions/Limitations

Pioglitazone significantly changes the visceral-subcutaneous fat distribution and plasma L/A ratio in non diabetic subjects on maintenance dialysis. This was associated with improved hepatic insulin sensitivity and a reduction of cardio-metabolic risk markers. Whether these effects may improve the outcome of non diabetic end-stage renal disease subjects on maintenance dialysis still needs further evaluation.

Trial Registration

ClinicalTrial.gov {"type":"clinical-trial","attrs":{"text":"NCT01253928","term_id":"NCT01253928"}}NCT01253928     

A human IgE bispecific antibody shows potent cytotoxic capacity mediated by monocytes

The generation of bispecific antibodies (bsAbs) targeting two different antigens opens a new level of specificity and, compared to mAbs, improved clinical efficacy in cancer therapy. Currently, the different strategies for development of bsAbs primarily focus on IgG isotypes. Nevertheless, in comparison to IgG isotypes, IgE has been shown to offer superior tumor control in preclinical models. Therefore, in order to combine the promising potential of IgE molecules with increased target selectivity of bsAbs, we developed dual tumor-associated antigen-targeting bispecific human IgE antibodies. As proof of principle, we used two different pairing approaches - knobs-into-holes and leucine zipper–mediated pairing. Our data show that both strategies were highly efficient in driving bispecific IgE formation, with no undesired pairings observed. Bispecific IgE antibodies also showed a dose-dependent binding to their target antigens, and cell bridging experiments demonstrated simultaneous binding of two different antigens. As antibodies mediate a major part of their effector functions through interaction with Fc receptors (FcRs) expressed on immune cells, we confirmed FcεR binding by inducing in vitro mast cell degranulation and demonstrating in vitro and in vivo monocyte-mediated cytotoxicity against target antigen-expressing Chinese hamster ovary cells. Moreover, we demonstrated that the IgE bsAb construct was significantly more efficient in mediating antibody-dependent cell toxicity than its IgG1 counterpart. In conclusion, we describe the successful development of first bispecific IgE antibodies with superior antibody-dependent cell toxicity–mediated cell killing in comparison to IgG bispecific antibodies. These findings highlight the relevance of IgE-based bispecific antibodies for clinical application.