HEMET: mathematical model of biochemical pathways for simulation and prediction of HEpatocyte METabolism

Many computer studies and models have been developed in order to simulate cell biochemical pathways. The difficulty of integrating all the biochemical reactions that occur in a cell in a single model is the main reason for the poor results in the prediction and simulation of cell behaviour under different chemical and physical stimuli. In this paper we have translated biochemical reactions into differential equations for the development of modular model of metabolism of a hepatocyte cultured in static and standard conditions (in a plastic multiwell placed in an incubator at 37 degrees C with 5% of CO(2)). Using biochemical equations and energetic considerations a set of non-linear differential equations has been derived and implemented in Simulink. This set of equations mimics some of the principal metabolic pathways of biomolecules present in the culture medium. The software platform developed is subdivided into separate modules, each one describing a different metabolic pathway; they constitute a library which can be used for developing new modules and models to project, predict and validate cell behaviour in vitro.

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.

A novel solution for severe urinary incontinence in women with cystic fibrosis

BACKGROUND

To explore whether Tension-free Vaginal Tape offers a solution for women with cystic fibrosis who suffer from severe stress incontinence.

METHODS

Four adults with cystic fibrosis were formally assessed by gynaecological and urological specialists, prior to hospital admission for surgery.

RESULTS

The procedure was tolerated well by all patients. In three, leakage ceased completely. The fourth patient experienced considerable improvement in symptoms.

CONCLUSIONS

Tension-free Vaginal Tape is a safe, effective and worthwhile solution for stress incontinence in females with cystic fibrosis.

Rapid-prototyped and salt-leached PLGA scaffolds condition cell morpho-functional behavior

Three dimensional scaffolds microfabricated using pressure-assisted microsyringe (PAM) with controlled geometry and porous membranes obtained using salt leaching were both tested with three different cell types to identify an optimal microstructural architecture for tissue engineering. MG63 (osteoblast-like cells) were used as models of mesenchymal bone tissue and human endothelial cells and NCTC2544 (keratinocytes) represented two epithelial tissues. Both porosity and stiffness of PLGA structures were measured, and cell morphology and cytoskeletal organization analyzed using SEM and actin labeling. The results show that overall the PAM scaffolds, which have a repeated and regular microstructure, are more biocompatible than the random pore salt-leached membranes, and that surface morphology as well as substrate stiffness modulates cell behavior.

Assessment of bioinspired models for pattern recognition in biomimetic systems

The increasing complexity of the artificial implementations of biological systems, such as the so-called electronic noses (e-noses) and tongues (e-tongues), poses issues in sensory feature extraction and fusion, drift compensation and pattern recognition, especially when high reliability is required. In particular, in order to achieve effective results, the pattern recognition system must be carefully designed. In order to investigate a novel biomimetic approach for the pattern recognition module of such systems, the classification capabilities of an artificial model inspired by the mammalian cortex, a cortical-based artificial neural network (CANN), are compared with several artificial neural networks present in the e-nose and e-tongue literature, a multilayer perceptron (MLP), a Kohonen self-organizing map (KSOM) and a fuzzy Kohonen self-organizing map (FKSOM). Each network was tested with large datasets coming from a conducting polymer-sensor-based e-nose and a composite array-based e-tongue. The comparison of results showed that the CANN model is able to strongly enhance the performances of both systems.

Mesalazine downregulates c-Myc in human colon cancer cells. A key to its chemopreventive action?

BACKGROUND

Dysplasia and malignant transformation of colonocytes in ulcerative colitis are associated with overexpression of c-Myc and genes regulating cell survival. 5-Aminosalicylates such as mesalazine may reduce the development of colorectal cancer in ulcerative colitis, but the mechanisms of its chemopreventive action are not clear.

AIMS

To examine whether mesalazine affects the expression of c-Myc in human colon cancer cell lines.

METHODS

Human colon cancer cells were treated with vehicle or mesalazine (4 mm or 40 mm). We examined: (i) mRNA expression by gene array, (ii) protein expression by Western blotting and immunohistochemistry and (iii) apoptosis by Annexin V labelling.

RESULTS

Mesalazine significantly reduced expression of c-Myc mRNA and protein.

CONCLUSIONS

Mesalazine downregulates gene and protein expression of c-Myc. The apoptotic and growth inhibitory effects of mesalazine are dose-dependent. Expression of c-Myc is significantly reduced by mesalazine 40 mm.

Microfabrication of fractal polymeric structures for capillary morphogenesis: Applications in therapeutic angiogenesis and in the engineering of vascularized tissue

Microfabrication techniques were combined with fractal algorithms to realize polymeric scaffolds resembling capillary networks. The scaffolds were seeded with human endothelial cells in monoculture as well as in coculture with human fibroblasts. To enhance the process of angiogenesis, endothelial cells were transfected with an adenoviral vector carrying the gene for human tissue kallikrien. The results demonstrate that both the presence of a structured scaffold as well as fibroblasts in coculture contribute synergically to the promotion of a metabolically active network. The fractal scaffolds have several possible applications for example in vascularized tissue engineering and therapeutic angiogenesis. A broader implication of these results is that cell-extra cellular matrix and cell-cell interactions cooperate dynamically both at a biochemical as well as microstructural level.

Novel aspects of endothelium-dependent regulation of vascular tone

The vascular endothelium plays a crucial role in the regulation of vascular homeostasis and in preventing the initiation and progress of cardiovascular disease by controlling mechanical functions of the underlying vascular smooth muscle. Three vasodilators: nitric oxide (NO), prostacyclin, and endothelium-derived hyperpolarizing factor, produced by the endothelium, underlie this activity. These substances act in a co-ordinated interactive manner to maintain normal endothelial function and operate as support mechanisms when one pathway malfunctions. In this review, we discuss recent advances in our understanding of how gender influences the interaction of these factors resulting in the vascular protective effects seen in pre-menopausal women. We also discuss how endothelial NO synthase (NOS) can act in both a pro- and anti-inflammatory action and therefore is likely to be pivotal in the initiation and time course of an inflammatory response, particularly with respect to inflammatory cardiovascular disorders. Finally, we review recent evidence demonstrating that it is not solely NOS-derived NO that mediates many of the beneficial effects of the endothelium, in particular, nitrite acts as a store of NO released during pathological episodes associated with NOS inactivity (ischemia/hypoxia). Each of these more recent findings has emphasized new pathways involved in endothelial biology, and following further research and understanding of the significance and mechanisms of these systems, it is likely that new and improved treatments for cardiovascular disease will result.

C-type natriuretic peptide: new candidate for endothelium-derived hyperpolarising factor

Endothelium-derived hyperpolarising factor (EDHF) is an important regulator of vascular tone; however, its identity is still unclear. Several different molecules have been suggested, the most recent of which is the 22-amino acid peptide C-type natriuretic peptide (CNP). CNP induces hyperpolarisation and relaxation of rat mesenteric resistance artery vascular smooth muscle through activation of natriuretic peptide receptor subtype C (NPR-C) and the same potassium channels as EDHF. In addition, this peptide is released from endothelial cells of the perfused rat mesenteric bed in response to endothelium-dependent vasodilators. Thus, CNP is likely to play a vital role in regulation of vascular tone. In addition, since there is evidence that up-regulation of EDHF occurs where normal endothelium function has been compromised, modulation of this pathway represents a novel target for therapeutics in the treatment of inflammatory cardiovascular pathologies characterised by endothelial dysfunction.

Tracheobronchial amyloidosis masquerading as bronchial asthma

A case of localized tracheobronchial primary amyloidosis masquerading as "bronchial asthma" is presented. Computed tomography of the chest and fiberoptic bronchoscopy image are included. Tracheobronchial primary amyloidosis is a rare, but potentially curable cause of airway obstruction mimicking asthma.

Microfabricated fractal branching networks

In this article, we demonstrate how a combination of engineering and biological techniques could lead to the realization of branched microstructures that can be used for the repair of damaged vascularized tissue. Recursive "treelike" networks were first generated by using fractal algorithms based on Murray's equation for vascular branching as well as allometric scaling rules. Two- and three-dimensional branching patterns with different levels of complexity were then microfabricated from poly-lactide-co-glycolide (PLGA) by using the pressure-assisted microsyringe (PAM) system developed in our laboratory. Human endothelial cells isolated from umbilical cords were seeded on the microfabricated branched scaffolds to evaluate their effectiveness in supporting site-specific cell adhesion. The results show that cell densities on the networks increase with complexity up to the sixth level and are then constant independent of branching level. The implications of this finding are discussed in terms of contact inhibition of "capillaries."