The K(ATP)+ channel is involved in a low-amplitude permeability transition in plant mitochondria

Pea (Pisum sativum) stem mitochondria, energized by NADH, succinate or malate plus glutamate, underwent a spontaneous low-amplitude permeability transition (PT), which could be monitored by dissipation of the electrical potential (deltapsi) or swelling. The occurrence of the latter effects was dependent on O2 availability, because O2 shortage anticipated the manifestation of both deltapsi dissipation and swelling. Spontaneous deltapsi collapse was also monitored in sucrose-resuspended mitochondria and again O2 deprivation caused an anticipation of the phenomenon. However, in this case deltapsi dissipation was not accompanied by a parallel mitochondrial swelling. The latter effect was, indeed, evident only if mitochondria were resuspended in KCl (as osmoticum), or other cations with a molecular mass up to 100 Da (choline+). PT was also induced by protonophores (carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) or free fatty acids) or valinomycin (only in KCl). The FCCP-induced dissipation of deltapsi and swelling were inhibited by ATP and stimulated (anticipated) by cyclosporin A or O2 shortage. The FCCP-induced PT was accompanied by the release of pyridine nucleotides from the matrix and of cytochrome c from the intermembrane space of KCl-resuspended mitochondria. The spontaneous and FCCP-induced low-amplitude PT of plant mitochondria are interpreted as due to the activity of a recently identified K(ATP)+ channel whose open/closed state is dependent on polarization of the inner membrane and on the oxidoreductive state of some sulfhydryl groups.     

New HPLC–MS method for the simultaneous quantification of the antileukemia drugs imatinib,dasatinib, and nilotinib in human plasma

A new method using high performance liquid chromatography coupled with electrospray mass spectrometry is described for the quantification of plasma concentration of tyrosine kinase inhibitors imatinib, dasatinib and nilotinib. A simple protein precipitation extraction procedure was applied on 250 μl of plasma aliquots. Chromatographic separation of drugs and Internal Standard (quinoxaline) was achieved with a gradient (acetonitrile and water + formic acid 0.05%) on a C18 reverse phase analytical column with 20 min of analytical run, at flow rate of 1 ml/min. Mean intra-day and inter-day precision for all compounds were 4.3 and 11.4%; mean accuracy was 1.5%; extraction recovery ranged within 95 and 114%. Calibration curves ranged from 10,000 to 62.5 ng/ml. The limit of quantification was set at 78.1 ng/ml for imatinib and at 62.5 ng/ml for dasatinib and nilotinib. This novel developed methodology allows a specific, sensitive and reliable simultaneous determination of the three tyrosine kinase inhibitors imatinib, dasatinib and nilotinib in a single chromatographic run, useful for drugs estimation in plasma of patients affected by chronic myeloid leukemia.     

Galvanic microparticles increase migration of human dermal fibroblasts in a wound-healing model via reactive oxygen species pathway

Electrical signals have been implied in many biological mechanisms, including wound healing, which has been associated with transient electrical currents not present in intact skin. One method to generate electrical signals similar to those naturally occurring in wounds is by supplementation of galvanic particles dispersed in a cream or gel. We constructed a three-layered model of skin consisting of human dermal fibroblasts in hydrogel (mimic of dermis), a hydrogel barrier layer (mimic of epidermis) and galvanic microparticles in hydrogel (mimic of a cream containing galvanic particles applied to skin). Using this model, we investigated the effects of the properties and amounts of Cu/Zn galvanic particles on adult human dermal fibroblasts in terms of the speed of wound closing and gene expression. The collected data suggest that the effects on wound closing are due to the ROS-mediated enhancement of fibroblast migration, which is in turn mediated by the BMP/SMAD signaling pathway. These results imply that topical low-grade electric currents via microparticles could enhance wound healing.     

Potential advantages of acute kidney injury management by mesenchymal stem cells

Mesenchymal stem cells are currently considered as a promising tool for therapeutic application in acute kidney injury (AKI) management. AKI is characterized by acute tubular injury with rapid loss of renal function. After AKI, inflammation, oxidative stress and excessive deposition of extracellular matrix are the molecular events that ultimately cause the end-stage renal disease. Despite numerous improvement of supportive therapy, the mortality and morbidity among patients remain high. Therefore, exploring novel therapeutic options to treat AKI is mandatory. Numerous evidence in animal models has demonstrated the capability of mesenchymal stem cells (MSCs) to restore kidney function after induced kidney injury. After infusion, MSCs engraft in the injured tissue and release soluble factors and microvesicles that promote cell survival and tissue repairing. Indeed, the main mechanism of action of MSCs in tissue regeneration is the paracrine/endocrine secretion of bioactive molecules. MSCs can be isolated from several tissues, including bone marrow, adipose tissue, and blood cord; pre-treatment procedures to improve MSCs homing and their paracrine function have been also described. This review will focus on the application of cell therapy in AKI and it will summarize preclinical studies in animal models and clinical trials currently ongoing about the use of mesenchymal stem cells after AKI.     

The Order of Exercise during Concurrent Training for Rehabilitation Does Not Alter Acute Genetic Expression,Mitochondrial Enzyme Activity or Improvements in Muscle Function

Concurrent exercise combines different modes of exercise (e.g., aerobic and resistance) into one training protocol, providing stimuli meant to increase muscle strength, aerobic capacity and mass. As disuse is associated with decrements in strength, aerobic capacity and muscle size concurrent training is an attractive modality for rehabilitation. However, interference between the signaling pathways may result in preferential improvements for one of the exercise modes. We recruited 18 young adults (10 ♂, 8 ♀) to determine if order of exercise mode during concurrent training would differentially affect gene expression, protein content and measures of strength and aerobic capacity after 2 weeks of knee-brace induced disuse. Concurrent exercise sessions were performed 3x/week for 6 weeks at gradually increasing intensities either with endurance exercise preceding (END>RES) or following (RES>END) resistance exercise. Biopsies were collected from the vastus lateralis before, 3 h after the first exercise bout and 48 h after the end of training. Concurrent exercise altered the expression of genes involved in mitochondrial biogenesis (PGC-1α, PRC, PPARγ), hypertrophy (PGC-1α4, REDD2, Rheb) and atrophy (MuRF-1, Runx1), increased electron transport chain complex protein content, citrate synthase and mitochondrial cytochrome c oxidase enzyme activity, muscle mass, maximum isometric strength and VO_2peak. However, the order in which exercise was completed (END>RES or RES>END) only affected the protein content of mitochondrial complex II subunit. In conclusion, concurrent exercise training is an effective modality for the rehabilitation of the loss of skeletal muscle mass, maximum strength, and peak aerobic capacity resulting from disuse, regardless of the order in which the modes of exercise are performed.