Cannabinoid CB1 receptor stimulation affords neuroprotection in MPTP-induced neurotoxicity by attenuating S100B up-regulation in vitro

In this study, we investigated the mechanism of S100B neurotoxicity and the effect of cannabinoids, in C6 cells treated with 1-methyl-4-phenyl 1,2,3,6 tetrahydropyridine (MPTP) and co-cultured with differentiated PC12 cells. MPTP concentration- and time-dependently increased S100B density in C6 cells. This effect was followed by increased C6 cell proliferation and decreased cell viability of co-cultured PC12 cells. An antibody against S100B, given to PC12 cells before co-culture, led to their survival. Treatment with arachidonyl-2-chloroethylamide, a CB1 agonist, significantly inhibited MPTP-induced S100B density in C6 cells and protected co-cultured PC12 cells from cell death. Because MPTP selectively increased the levels of anandamide in C6 cells, the involvement of the endocannabinoid system was investigated by using selective inhibitors of endocannabinoid inactivation (cellular re-uptake or enzymatic hydrolysis) and selective cannabinoid CB1 and CB2 receptor antagonists and by silencing the CB1 receptor. Our data suggest that selective activation of CB1 receptors by either exogenous or endogenous cannabinoids might afford neuroprotection in MPTP-induced neurotoxicity also by controlling S100B up-regulation in activated glial cells.     

Optically Active Methacrylic Copolymers Bearing Side‐Chain Bisazoaromatic and Bulky Achiral Moieties

The synthesis of two novel series of optically active methacrylic copolymers that contain a side‐chain chiral moiety linked to a photochromic bisazoaromatic chromophore has been carried out by radical copolymerization of the monomer (S)‐3‐methacryloyloxy‐1‐[4′‐phenylazo‐(4‐azobenzene)]pyrrolidine with highly sterically hindered monomers such as tert‐butyl methacrylate or triphenylmethyl methacrylate with the aim to investigate the effect on the optical activity of the resulting derivatives. The copolymeric products have been fully characterized and their spectroscopic and thermal properties compared to those of the related optically active homopolymer and the copolymers with methyl methacrylate, previously reported. The optical activity displayed by the polymers is discussed in terms of extent of chiral conformations assumed by the macromolecules as a consequence of the insertion of co‐monomers capable of affecting the dipole‐dipole interactions that occur in these derivatives between the side‐chain bisazoaromatic chromophores disposed according to a mutual chiral arrangement.

     

New Optically Active Methacrylic Polymers Bearing Side‐Chain Bisazoaromatic Moieties

The synthesis of three novel optically active monomers containing a side‐chain chiral moiety linked to a photochromic bisazoaromatic chromophore, such as (S)‐3‐methacryloyloxy‐1‐[4′‐phenylazo‐(4‐azobenzene)]‐pyrrolidine [(S)‐ MPAAP ], (S)‐3‐methacryloyloxy‐1‐[4′‐cyanophenylazo‐(4‐azobenzene)]‐pyrrolidine [(S)‐ MPAAP‐C ] and (S)‐3‐methacryloyloxy‐1‐[4′‐nitrophenylazo‐(4‐azobenzene)]‐pyrrolidine [(S)‐ MPAAP‐N ], is described. Each monomer has been radically homopolymerized to afford the corresponding optically active polymeric derivative, which have been characterized, in solution and in the solid state, and their properties compared to those of the monomers and of analogous homopolymers bearing only one azoaromatic chromophore in the side chain. The optical activity displayed by the polymers is discussed in terms of extent of chiral conformation assumed by the macromolecules as a consequence of their stiffness and the dipole‐dipole interactions between the bisazoaromatic chromophores.

     

Multiplane transesophageal echocardiography performed according to the guidelines of the American Society of Echocardiography in patients with mitral valve prolapse, flail, and endocarditis: diagnostic accuracy in the identification of mitral regurgitant defects by correlation with surgical findings.

Multiplane transesophageal echocardiography is a useful tool to study mitral regurgitation. We evaluated the diagnostic accuracy of multiplane transesophageal echocardiography performed according to the guidelines of the American Society of Echocardiography. We used 4 midesophageal and 2 transgastric views in 313 patients with degenerative lesions, endocarditic lesions, or both to identify regurgitant defects, comparing transesophageal echocardiography results with surgical findings. The overall diagnostic accuracy using individual scallops was 97.2% (P <.00001) with a sensitivity of 96.6% and a specificity of 97.6%. Considering the single sections of the mitral valve, an accuracy of 98%, 97.1%, and 98%, was found, respectively, for the lateral, middle, and medial third of the anterior leaflet. For the posterior leaflet, the accuracy was 98% for the lateral scallop, 98.4% for the middle, and 96.1% for the medial. This strategy provides good accuracy in diagnosing both simple and challenging mitral-valve lesions and its widespread use should be recommended.     

An in vitro expansion score for tissue‐engineering applications with human bone marrow‐derived mesenchymal stem cells

Human bone marrow‐derived mesenchymal stem cells (MSCs) have limited growth potential in vitro and cease to divide due to replicative senescence, which from a tissue‐engineering perspective has practical implications, such as defining the correct starting points for differentiation and transplantation. Time spent in culture before the loss of required differentiation potential is different and reflects patient variability, which is a problem for cell expansion. This study aimed to develop a score set which can be used to quantify the senescent state of MSCs and predict whether cells preserve their ability to differentiate to osteogenic, adipogenic and chondrogenic phenotypes, based on colony‐forming unit (CFU) assay, population doubling time (PDT), senescence‐associated β‐galactosidase (SA‐β‐Gal) activity, cell size, telomere length and gene expression of MSCs cultured in vitro over 11 passages. This set of morphological, physiological and genetic senescence markers was correlated to the ability of MSCs to differentiate. Differentiation efficiency was assessed by marker genes and protein expression. CFUs decreased with increasing passage number, whereas SA‐β‐Gal activity and PDT increased; however, the correlation with MSCs' differentiation potential was sometimes unexpected. The expression of genes related to senescence was higher in late‐passage cells than in early‐passage cells. Early‐passage cells underwent efficient osteogenic differentiation, with mid‐passage cells performing best in chondrogenic differentiation. Late‐passage cells preserve only adipogenic differentiation potential. Based on this marker set, we propose a senescence score in which combined markers give a reliable quality control of MSCs, not depending only on mechanistic passage number. Copyright © 2013 John Wiley & Sons, Ltd.     

High-density lipoproteins reduce the intestinal damage associated with ischemia/reperfusion and colitis

High-density lipoproteins (HDLs) have been shown to reduce the organ injury and mortality in animal models of shock by reducing the expression of adhesion molecules and proinflammatory enzymes. However, there is limited evidence that HDL treatment reduces inflammation. As inflammation plays an important role in the development of colitis as well as ischemia/reperfusion (I/R) injury of the intestine, we have investigated the effects of HDL in animal models of associated with gut injury and inflammation (splanchnic artery occlusion [SAO] shock and dinitrobenzene sulfonic acid [DNBS]-induced colitis). We report here for the first time that the administration of reconstituted HDLs (recHDLs; 80 mg/kg i.v. bolus 30 min prior to ischemia in the SAO-shock model or 40 mg/kg i.v. every 24 h in the colitis model) exerts potent anti-inflammatory effects (e.g., reduced inflammatory cell infiltration and histological injury, and delayed the development of the clinical signs) in vivo. Furthermore, recHDL reduced the staining for nitrotyrosine and poly(ADP-ribose) (immunohistochemistry) and the expression of intercellular adhesion molecule-1 in the ileum of SAO-shocked rats and in the colon from DNBS-treated rats. Thus, recHDL reduces the inflammation caused by intestinal I/R and colitis. HDLs may represent a novel therapeutic approach for the therapy of inflammation of the gut.