Local inhibition of ornithine decarboxylase reduces vascular stenosis in a murine model of carotid injury

Objectives: Polyamines are organic polycations playing an essential role in cell proliferation and differentiation, as well as in cell contractility, migration and apoptosis. These processes are known to contribute to restenosis, a pathophysiological process often occurring in patients submitted to revascularization procedures. We aimed to test the effect of alpha-difluoromethylornithine (DFMO), an inhibitor of ornithine decarboxylase, on vascular cell pathophysiology in vitro and in a rat model of carotid arteriotomy-induced (re) stenosis. Methods: The effect of DFMO on primary rat smooth muscle cells (SMCs) and mouse microvascular bEnd. 3 endothelial cells (ECs) was evaluated through the analysis of DNA synthesis, polyamine concentration, cell viability, cell cycle phase distribution and by RT-PCR targeting cyclins and genes belonging to the polyamine pathway. The effect of DFMO was then evaluated in arteriotomy-injured rat carotids through the analysis of cell proliferation and apoptosis, RT-PCR and immunohistochemical analysis of differential gene expression. Results: DFMO showed a differential effect on SMCs and on ECs, with a marked, sustained anti-proliferative effect of DFMO at 3 and 8 days of treatment on SMCs and a less pronounced, late effect on bEnd. 3 ECs at 8 days of DFMO treatment. DFMO applied perivascularly in pluronic gel at arteriotomy site reduced subsequent cell proliferation and preserved smooth muscle differentiation without affecting the endothelial coverage. Lumen area in DFMO-treated carotids was 49% greater than in control arteries 4 weeks after injury. Conclusions: Our data support the key role of polyamines in restenosis and suggest a novel therapeutic approach for this pathophysiological process. (C) 2013 Elsevier Ireland Ltd. All rights reserved

Intake and metabolism of omega-3 and omega-6 polyunsaturated fatty acids: nutritional implications for cardiometabolic diseases

Prospective observational studies support the use of long-chain omega-3 polyunsaturated fatty acids (PUFAs) in the primary prevention of atherosclerotic cardiovascular disease; however, randomised controlled trials, have often reported neutral findings. There is a long history of debate about the potential harmful effects of a high intake of omega-6 PUFAs, although this idea is not supported by prospective observational studies or randomised controlled trials. Health effects of PUFAs might be influenced by Δ-5 and Δ-6 desaturases, the key enzymes in the metabolism of PUFAs. The activity of these enzymes and modulation by variants in encoding genes (FADS1-2-3 gene cluster) are linked to several cardiometabolic traits. This Review will further consider non-genetic determinants of desaturase activity, which have the potential to modify the availability of PUFAs to tissues. Finally, we discuss the consequences of altered desaturase activity in the context of PUFA intake, that is, gene–diet interactions and their clinical and public health implications

Cholesterol catalyses Aβ42 aggregation through a heterogeneous nucleation pathway in the presence of lipid membranes.

Alzheimer's disease is a neurodegenerative disorder associated with the aberrant aggregation of the amyloid-β peptide. Although increasing evidence implicates cholesterol in the pathogenesis of Alzheimer's disease, the detailed mechanistic link between this lipid molecule and the disease process remains to be fully established. To address this problem, we adopt a kinetics-based strategy that reveals a specific catalytic role of cholesterol in the aggregation of Aβ42 (the 42-residue form of the amyloid-β peptide). More specifically, we demonstrate that lipid membranes containing cholesterol promote Aβ42 aggregation by enhancing its primary nucleation rate by up to 20-fold through a heterogeneous nucleation pathway. We further show that this process occurs as a result of cooperativity in the interaction of multiple cholesterol molecules with Aβ42. These results identify a specific microscopic pathway by which cholesterol dramatically enhances the onset of Aβ42 aggregation, thereby helping rationalize the link between Alzheimer's disease and the impairment of cholesterol homeostasis

Isolation and individual electrical stimulation of single smooth-muscle cells from the urinary bladder of the pig

In contrast to striated muscle, measurements on strips of smooth muscle cannot be uniquely interpreted in terms of an array of contractile units. Therefore scaling down to the single-cell level is necessary to gain detailed understanding of the contractile process in this type of muscle. The present study describes the development of a method for isolating contractile single smooth muscle cells from pig urinary bladders. Contractile responses evoked by individual electrical stimulation were used as a measure of cell quality during development of the method. Responses were evaluated by measuring latency, contraction and relaxation times, as indicated by visible length changes, and stored on-line in a computer. Initial length, relative shortening and shortening speed were determined by measuring cell lengths in previously timed still video frames using a computer-controlled crosshair device. Increase of stimulus pulse duration resulted in improved responses, indicating that the observed shortening represented a physiological contractile response. Ultimately this method of evaluation was applied to two sets of cell preparations obtained by two different methods, one using only collagenase digestion, the other using mechanical manipulation as well. Both sets showed two main patterns of response to electrical stimulation: a pattern of contraction upon stimulation followed by enhanced contraction when stimulation was switched off (CK), and a pattern of contraction upon stimulation followed by relaxation when the stimulus was switched off (CR). The set of preparations containing the highest percentage of CR cells was found to be superior (i.e. greater initial length, shorter latency and contraction times, increased shortening and higher shortening speed). The method of isolation used for this set gives a high yield of contractile cells available for experimental use over a long span of time

Psychosocial and symbolic dimensions of the breast explored through a Visual Matrix

This article explores knowledge about the breast in the psychosocial interplay of lived experience, addressing a gap in empirical research on this highly gendered cultural trope and embodied organ. We present findings from a study that used a free-associative psychosocial method – the Visual Matrix – in order to stimulate, and capture expressions of, tacit aspects of the breast that have evaded discursive representation, as well as to generate understanding of relations between embodied and enculturated experience. Little research has been conducted on women’s affirmative experience of breasts, possibly because their bio-psycho-sociocultural complexity affords an onto-epistemological and empirical challenge. Our data revealed how an aesthetic of the grotesque in one matrix allowed the mainly female group to use humour as a “creative psychic defence” against culturally normative and idealised aspects of the breast. This was expressed through sensual symbolisations of breasted experience, affectively delivered with exuberance and joy. There was an emphasis on the breast’s potency and its potential for both abundant nurturance and potent “weaponisation”. By establishing this feminine poetic mode, Visual Matrix imagery symbolised life and death as tolerable, inseparable yet ambiguous dimensions of breasts, thereby resisting anxious splitting. The breast’s life-affirming qualities included the sensual, the visceral and the joyful – a materialsemiotic knowing. This was in marked contrast to a second matrix where associations were weighted towards the spectacular breast of an ocular-centric culture that privileges heteromasculine looking. This matrix reflected a more ambivalent and sometimes troubled response among participants. Reasons for the difference between the two matrices are discussed in terms of how they responded to the tension between embodied and enculturated experiences

Intrinsic Determinants of Aβ12–24 pH-Dependent Self-Assembly Revealed by Combined Computational and Experimental Studies

The propensity of amyloid- (A) peptide to self-assemble into highly ordered amyloid structures lies at the core of their accumulation in the brain during Alzheimer's disease. By using all-atom explicit solvent replica exchange molecular dynamics simulations, we elucidated at the atomic level the intrinsic determinants of the pH-dependent dimerization of the central hydrophobic segment A and related these with the propensity to form amyloid fibrils measured by experimental tools such as atomic force microscopy and fluorescence. The process of A dimerization was evaluated in terms of free energy landscape, side-chain two-dimensional contact probability maps, -sheet registries, potential mean force as a function of inter-chain distances, secondary structure development and radial solvation distributions. We showed that dimerization is a key event in A amyloid formation; it is highly prompted in the order of pH 5.02.98.4 and determines further amyloid growth. The dimerization is governed by a dynamic interplay of hydrophobic, electrostatic and solvation interactions permitting some variability of -sheets at each pH. These results provide atomistic insight into the complex process of molecular recognition detrimental for amyloid growth and pave the way for better understanding of the molecular basis of amyloid diseases

Cervical squamous carcinoma cells are resistant to the combined action of tumor necrosis factor-α and histamine whereas normal keratinocytes undergo cytolysis

<p>Abstract</p> <p>Background</p> <p>Previous reports showed that mast cells can typically be found in the peritumoral stroma of cervix carcinomas as well as in many other cancers. Both histamine and TNF-α are potent preformed mast cell mediators and they can act simultaneously after release from mast cells. Thus, the effect of TNF-α and histamine on cervical carcinoma cell lines was studied.</p> <p>Methods and results</p> <p>TNF-α alone induced slight growth inhibition and cell cycle arrest at G0/G1 phase in SiHa cells, but increased their migration. Histamine alone had no effect on cells. In addition, TNF-α and histamine in combination showed no additional effect over that by TNF-α alone, although SiHa cells were even pretreated with a protein synthesis inhibitor. Furthermore, TNF-α-sensitive ME-180 carcinoma cells were also resistant to the combination effect of TNF-α and histamine. In comparison, TNF-α or histamine alone induced growth inhibition in a non-cytolytic manner in normal keratinocytes, an effect that was further enhanced to cell cytolysis when both mediators acted in combination. Keratinocytes displayed strong TNF receptor (TNFR) I and II immunoreactivity, whereas SiHa and ME-180 cells did not. Furthermore, cervix carcinoma specimens revealed TNF-α immunoreactivity in peritumoral cells and carcinoma cells. However, the immunoreactivity of both TNFRs was less intense in carcinoma cells than that in epithelial cells in cervical specimens with non-specific inflammatory changes.</p> <p>Conclusion</p> <p>SiHa and ME-180 cells are resistant to the cytolytic effect of TNF-α and histamine whereas normal keratinocytes undergo cytolysis, possibly due to the smaller amount of TNFRs in SiHa and ME-180 cells. In the cervix carcinoma, the malignant cells may resist this endogenous cytolytic action and TNF-α could even enhance carcinoma cell migration.</p

Review of nanomaterials in dentistry: interactions with the oral microenvironment, clinical applications, hazards, and benefits.

Interest in the use of engineered nanomaterials (ENMs) as either nanomedicines or dental materials/devices in clinical dentistry is growing. This review aims to detail the ultrafine structure, chemical composition, and reactivity of dental tissues in the context of interactions with ENMs, including the saliva, pellicle layer, and oral biofilm; then describes the applications of ENMs in dentistry in context with beneficial clinical outcomes versus potential risks. The flow rate and quality of saliva are likely to influence the behavior of ENMs in the oral cavity, but how the protein corona formed on the ENMs will alter bioavailability, or interact with the structure and proteins of the pellicle layer, as well as microbes in the biofilm, remains unclear. The tooth enamel is a dense crystalline structure that is likely to act as a barrier to ENM penetration, but underlying dentinal tubules are not. Consequently, ENMs may be used to strengthen dentine or regenerate pulp tissue. ENMs have dental applications as antibacterials for infection control, as nanofillers to improve the mechanical and bioactive properties of restoration materials, and as novel coatings on dental implants. Dentifrices and some related personal care products are already available for oral health applications. Overall, the clinical benefits generally outweigh the hazards of using ENMs in the oral cavity, and the latter should not prevent the responsible innovation of nanotechnology in dentistry. However, the clinical safety regulations for dental materials have not been specifically updated for ENMs, and some guidance on occupational health for practitioners is also needed. Knowledge gaps for future research include the formation of protein corona in the oral cavity, ENM diffusion through clinically relevant biofilms, and mechanistic investigations on how ENMs strengthen the tooth structure