Drug Repurposing by Simulating Flow Through Protein-Protein Interaction Networks.

As drug development is extremely expensive, the identification of novel indications for in-market drugs is financially attractive. Multiple algorithms are used to support such drug repurposing, but highly reliable methods combining simulation of intracellular networks and machine learning are currently not available. We developed an algorithm that simulates drug effects on the flow of information through protein-protein interaction networks, and used support vector machine to identify potentially effective drugs in our model disease, psoriasis. Using this method, we screened about 1,500 marketed and investigational substances, identified 51 drugs that were potentially effective, and selected three of them for experimental confirmation. All drugs inhibited tumor necrosis factor alpha-induced nuclear factor kappa B activity in vitro, suggesting they might be effective for treating psoriasis in humans. Additionally, these drugs significantly inhibited imiquimod-induced ear thickening and inflammation in the mouse model of the disease. All results suggest high prediction performance for the algorithm.

Anti-irritant and anti-inflammatory effects of glycerol and xylitol in sodium lauryl sulphate-induced acute irritation.

BACKGROUND: Glycerol is known to possess anti-irritant and hydrating properties and previous studies suggested that xylitol may also have similar effects. OBJECTIVE: Our aim was to study whether different concentrations of these polyols restore skin barrier function and soothe inflammation in sodium lauryl sulphate (SLS)-induced acute irritation. METHODS: The experiments were performed on male SKH-1 hairless mice. The skin of the dorsal region was exposed to SLS (5%) for 3 h alone or together with 5% or 10% of glycerol respectively. Further two groups received xylitol solutions (8.26% and 16.52% respectively) using the same osmolarities, which were equivalent to those of the glycerol treatments. The control group was treated with purified water. Transepidermal water loss (TEWL) and skin hydration were determined. Microcirculatory parameters of inflammation were observed by means of intravital videomicroscopy (IVM). Furthermore, accumulation of neutrophil granulocytes and lymphocytes, the expression of inflammatory cytokines and SLS penetration were assessed, as well. RESULTS: Treatment with the 10% of glycerol and both concentrations of xylitol inhibited the SLS-induced elevation of TEWL and moderated the irritant-induced increase in dermal blood flow and in the number of leucocyte-endothelial interactions. All concentrations of the applied polyols improved hydration and prevented the accumulation of lymphocytes near the treatment site. At the mRNA level, neither glycerol nor xylitol influenced the expression of interleukin-1 alpha. However, expression of interleukin-1 beta was significantly decreased by the 10% glycerol treatment, while expression of tumour necrosis factor-alpha decreased upon the same treatment, as well as in response to xylitol. Higher polyol treatments decreased the SLS penetration to the deeper layers of the stratum corneum. CONCLUSION: Both of the analysed polyols exert considerable anti-irritant and anti-inflammatory properties, but the effective concentration of xylitol is lower than that of glycerol.

Cortical and trabecular bone at the radius and tibia in postmenopausal breast cancer patients: a Peripheral Quantitative Computed Tomography (pQCT) study.

Bone morbidity associated with antineoplastic treatment is a significant health concern for postmenopausal breast cancer patients. Trials have demonstrated that adjuvant therapy with an Aromatase Inhibitor is associated with an increase in musculoskeletal disorders and bone fractures. The objective of this study was to utilize Peripheral Quantitative Computed Tomography (pQCT) to assess in vivo trabecular and cortical volumetric bone at peripheral skeletal sites in healthy postmenopausal women and breast cancer patients prescribed Anastrozole. Fifty-eight women were recruited for this study: 27 breast cancer patients and 31 healthy control participants. pQCT measurements were taken at distal and diaphyseal sites of the radius and tibia using a Stratec XCT-2000 pQCT scanner. Bone measurement values for total density and total content at the 4% radius; total and cortical content as well as cortical density at the 20% radius; total density at the 4% tibia; and cortical density at the 38% tibia were found to be significantly lower in breast cancer patients. Moreover, the duration of time on Anastrozole showed a significant negative correlation with the following measurements: total content at the 4% radius (r=-0.36, p<0.01); total content (r=-0.33, p<0.05), cortical content (r=-0.34, p<0.05) and cortical density (r=-0.44, p<0.01) at the 20% radius; as well as cortical density (r=-0.39, p<0.01) and cortical content (r=-0.27, p<0.05) at the 38% tibia. Overall, the breast cancer patients demonstrated significantly lower values for volumetric bone density and content at the radius and tibia compared with healthy postmenopausal women. Furthermore, this novel study found adverse effects from Anastrozole treatment primarily in cortical bone.

Stereologic evaluation of the vasculature in a MX1 xenotransplanted tumour model after combinations of treatment with ifosfamide, hyperthermia and irradiation.

The vascularization of tumours is a critical parameter of their growing and metastatic behaviour. However, little is known about the morphologic reactions of the microvasculature, especially the capillary bed of tumours and the adjacent tissue. In this study, the vessels in MX1 xenotransplants in athymic nu/nu nude mice were quantified and the angioarchitecture was visualized with the aim of presenting stereologic parameters of vessels based on a morphometric analysis of post mortem tissue blocks which were processed by standard histological procedures. In order to study changes of the microvasculature of MX1 tumours, the xenotransplanted nude mice were treated by different therapeutic regimens. Standardized hyperthermia, ifosfamide and irradiation therapies were applied. Special interest was focused on early changes of capillaries and of the pre- as well as post-terminal vascular bed. The stereologic evaluation of capillaries and larger vessels immediately after the therapy with ifosfamide and hyperthermia shows an increase of the mean capillary sizes. Furthermore, tumour samples after the 5th day of irradiation (5 x 2 Gy) and combinations of irradiation and chemotherapy treatment have been investigated. After 5 days of irradiation, a significant decrease of the vascular density was found. The results presented here clearly show that the timing and the mode of therapy influence the capillary morphology and periterminal vasculature of xenotransplanted MX1 tumours.

Characterization of the human multidrug resistance protein containing mutations in the ATP-binding cassette signature region.

A number of mutants with single amino acid replacements were generated in the highly conserved ATP-binding cassette (ABC)-signature region (amino acids 531-543) of the N-terminal half of the human multidrug resistance (MDR1) protein. The cDNA variants were inserted into recombinant baculoviruses and the MDR1 proteins were expressed in Spodoptera frugiperda (Sf9) insect cells. The level of expression and membrane insertion of the MDR1 variants was examined by immunostaining, and MDR1 function was followed by measuring drug-stimulated ATPase activity. We found that two mutations, L531R and G534V, practically eliminated MDR1 expression; thus these amino acid replacements seem to inhibit the formation of a stable MDR1 protein structure. The MDR1 variants G534D and I541R were expressed at normal levels with normal membrane insertion, but showed a complete loss of drug-stimulated ATPase activity, while mutant R538M yielded full protein expression but with greatly decreased ATPase activity. Increasing the ATP concentration did not restore MDR1 ATPase activity in these variants. Some amino acid replacements in the ABC-signature region (K536I, K536R, I541T and R543S) affected neither the expression and membrane insertion nor the ATPase function of MDR1. We found no alteration in the drug-sensitivity of ATP cleavage in any of the MDR1 variants that had measurable ATPase activity. These observations suggest that the ABC-signature region is essential for MDR1 protein stability and function, but alterations in this region do not seem to modulate MDR1-drug interactions directly.

Results of transcutaneous electrical stimulation (TES) in cure of lower extremity arterial disease.

The results of the treatment of 24 subjects--10 of them diabetic--with peripheral obstructive arterial disease of the lower limbs by transcutaneous electrical stimulation (TES) have been studied. The chronic ischemia of the lower extremities was complicated with ulceration in 12 and initial or advanced gangrene in 6 patients. All patients had been treated with antiplatelet drugs, pentoxifylline, and vasodilating drugs for many years. The drug therapy was continued, and TES was given daily for twenty minutes. The results were estimated after four to eight weeks of hospitalization and during a one-year follow-up in numerous cases. Except for 4 patients the improvement was very significant in all cases: the pain disappeared, the gangrenous process of the toes stopped, regression or complete healing of the ulceration could be observed, and the painfree walking distance increased. The oxygen saturation measured on the toes increased significantly during electrical stimulation. The blood pressure measured in the tibial artery showed very different changes. According to these observations TES appears to be a useful method superior to drug therapy in curing arterial circulatory disturbances of the lower extremities.