Previously, we demonstrated that supplementation of resuscitation fluids with the Kv7 voltage-activated potassium channel inhibitor linopirdine reduces fluid resuscitation requirements and stabilizes hemodynamics in various rat models of hemorrhagic shock. To further evaluate the therapeutic potential of linopirdine, we tested the effects of linopirdine-supplemented resuscitation fluids in a rat model of ischemia-reperfusion injury-induced acute respiratory distress syndrome (ARDS). Ventilated rats underwent unilateral lung ischemia from t=0-75 min, followed by lung reperfusion and fluid resuscitation to a mean arterial blood pressure of 60 mmHg with normal saline (NS, n=9) or NS supplemented with 50 μg/ml linopridine (NS-L), n=7) until t=360 min. As compared with NS, fluid resuscitation with NS-L stabilized blood pressure and reduced fluid requirements by 40% (p<0.05 vs. NS at t=240-360 min). While NS-L did not affect ARDS development, it reduced mortality from 66% with NS to 14% with NS-L (p=0.03, hazard ratio 0.14; 95% confidence interval of the hazard ratio: 0.03-0.65). Median survival time was 240 min with NS and >360 min with NS-L. As compared with NS treated animals that survived the observation period (n=3), however, plasma lactate and creatinine concentrations at t=360 min were higher with NS-L (n=6; p<0.05). Our findings extend therapeutic potential of NS-L from hypovolemic/hemorrhagic shock to hemodynamic instability under normovolemic conditions during organ ischemia-reperfusion injury. Possible adverse effects of NS-L, such as impairment of renal function and/or organ hypoperfusion, require further evaluation in long-term pre-clinical models.

• MeSH
• blokátory draslíkových kanálů aplikace a dávkování   MeSH
• časové faktory MeSH
• indoly aplikace a dávkování   MeSH
• intravenózní infuze MeSH
• krevní tlak účinky léků   MeSH
• modely nemocí na zvířatech MeSH
• potkani Sprague-Dawley MeSH
• pyridiny aplikace a dávkování   MeSH
• reperfuzní poškození komplikace   MeSH
• resuscitace * MeSH
• solný roztok aplikace a dávkování   MeSH
• syndrom dechové tísně etiologie   patofyziologie   terapie   MeSH
• tekutinová terapie * MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Chemokine (C-X-C motif) receptor 4 (CXCR4) agonists have been shown to protect lung endothelial barrier function in vitro. In vivo effects of CXCR4 modulation on lung endothelial permeability are unknown. Here we tested the effects of the CXCR4 agonist ubiquitin and the antagonist AMD3100 on lung vascular permeability and cytokine concentrations in a rat hemorrhage model. Animals were hemorrhaged (mean arterial blood pressure 30 mmHg for 30 min), treated with vehicle, ubiquitin (0.7 and 3.5 µmol/kg) or AMD3100 (3.5 µmol/kg), and resuscitated with crystalloids. Evans blue extravasation was employed to quantify lung vascular permeability. Ubiquitin dose-dependently reduced Evans blue extravasation into the lung. AMD3100 increased Evans blue extravasation. With AMD3100, TNFalpha levels in lung homogenates were increased; while TNFalpha levels were lower with ubiquitin, these differences did not reach statistical significance. Our findings suggest that CXCR4 regulates lung vascular permeability and further point towards CXCR4 as a drug target to confer lung protection during resuscitation from traumatic-hemorrhagic shock.

• MeSH
• hemoragický šok metabolismus   terapie   MeSH
• heterocyklické sloučeniny farmakologie   MeSH
• kapilární permeabilita fyziologie   účinky léků   MeSH
• krysa rodu rattus MeSH
• mediátory zánětu antagonisté a inhibitory   metabolismus   MeSH
• potkani Sprague-Dawley MeSH
• receptory CXCR4 agonisté   antagonisté a inhibitory   fyziologie   MeSH
• respirační sliznice metabolismus   účinky léků   MeSH
• resuscitace * trendy   MeSH
• ubikvitin farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Several diseases induce hypermetabolism, which is characterized by increases in resting energy expenditures (REE) and whole body protein loss. Exaggerated protein degradation is thought to be the driving force underlying this response. The effects of caspase and calpain inhibitors on REE in physiological and hypermetabolic conditions, however, are unknown. Thus, we studied whether MDL28170 (calpain inhibitor) or z-VAD-fmk (caspase inhibitor) affect REE under physiological conditions and during hypermetabolism post-burn. Rats were treated five times weekly and observed for 6 weeks. Treatment was started 2 h (early) or 48 h (late) after burn. In normal rats, MDL28170 transiently increased REE to 130 % of normal during week 2-4. z-VAD-fmk reduced REE by 20-25 % throughout the observation period. Within 14 days after burns, REE increased to 130+/-5 %. Whereas MDL28170/early treatment did not affect REE, MDL28170/late transiently increased REE to 180+/-10 % of normal by week 4 post-burn. In contrast, with z-VAD-fmk/early REE remained between 90-110 % of normal post-burn. z-VAD-fmk/late did not affect burn-induced increases in REE. These data suggest that caspase cascades contribute to the development of hypermetabolism and that burn-induced hypermetabolism can be pharmacologically modulated. Our data point towards caspase cascades as possible therapeutic targets to attenuate hypermetabolism after burns, and possibly in other catabolic disease processes.

• MeSH
• chloromethylketony aminokyselin farmakologie   terapeutické užití   MeSH
• dipeptidy farmakologie   terapeutické užití   MeSH
• energetický metabolismus účinky léků   MeSH
• inhibitory cysteinových proteinas farmakologie   terapeutické užití   MeSH
• inhibitory kaspas farmakologie   terapeutické užití   MeSH
• metabolické nemoci farmakoterapie   etiologie   MeSH
• pilotní projekty MeSH
• popálení komplikace   MeSH
• potkani Sprague-Dawley MeSH
• preklinické hodnocení léčiv MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Proteasomes appear to be involved in the pathophysiology of various acute and chronic lung diseases. Information on the human lung proteasome in health and disease, however, is sparse. Therefore, we studied whether end-stage pulmonary diseases are associated with alterations in lung 20S/26S proteasome content, activity and 20S subunit composition. Biopsies were obtained from donor lungs (n=7) and explanted lungs from patients undergoing lung transplantation because of end stage chronic obstructive pulmonary disease (COPD; n=7), idiopathic pulmonary fibrosis (IPF, n=7) and pulmonary sarcoidosis (n=5). 20S/26S proteasomes in lung extracts were quantified by ELISA, chymotrypsin-like proteasome peptidase activities measured and 20S proteasome beta subunits analyzed by Western blot. As compared with donor lungs, proteasome content was increased in IPF and sarcoidosis, but not in COPD. The relative distribution of free 20S and 26S proteasomes was similar; 20S proteasome was predominant in all extracts. Proteasome peptidase activities in donor and diseased lungs were indistinguishable. All extracts contained a mixed composition of inducible 20S beta immuno-subunits and their constitutive counterparts; a disease associated distribution could not be identified. A higher content of lung proteasomes in IPF and pulmonary sarcoidosis may contribute to the pathophysiology of human fibrotic lung diseases.

• MeSH
• dárci tkání MeSH
• lidé středního věku MeSH
• lidé MeSH
• pilotní projekty MeSH
• plíce metabolismus   MeSH
• plicní nemoci metabolismus   MeSH
• proteasomový endopeptidasový komplex metabolismus   MeSH
• senioři MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Effects of ectopic pacing on left ventricular repolarization were studied in six anesthetized open-chest chickens. In each animal, unipolar electrograms were acquired from as many as 98 sites with 14 plunge needles (seven transmural locations between epicardium and endocardium in each needle). Activation-recovery intervals (ARIs), corrected to the cycle length, were used for estimating repolarization. At baseline, the nonuniform ARI distribution in the left ventricle resulted in the apicobasal differences being greater than the transmural gradient. Nonuniform ARI prolongation caused by ectopic pacing resulted in decreasing the transmural repolarization gradient and increasing the differences in the apex-to-base direction. The basal, but not apical transmural differences contributed to the total left ventricular transmural gradient. The total left ventricular apicobasal gradient was contributed by the apicobasal differences in mid-myocardial and subendocardial layers more than in subepicardial ones. Thus, in in situ chicken hearts, the transmural and apicobasal ARI gradients exist within the left ventricle with the shortest ARIs in the basal subepicardium and the longest ARIs in the subendocardium of the apical and middle parts of the left ventricle. Apicobasal compared to transmural heterogeneity of local repolarization properties contributes more to the total left ventricular repolarization gradient.

• MeSH
• akční potenciály MeSH
• časové faktory MeSH
• elektrokardiografie MeSH
• endokard fyziologie   MeSH
• financování organizované MeSH
• funkce levé komory srdeční MeSH
• kardiostimulace umělá MeSH
• kur domácí MeSH
• perikard fyziologie   MeSH
• převodní systém srdeční fyziologie   MeSH
• srdeční frekvence fyziologie   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH

The ubiquitin-proteasome pathway fulfills major biological functions, but its physiologic tissue distribution and the interrelationship between pathway component activities and ubiquitin pools are unknown. Therefore, we analyzed free and conjugated ubiquitin, ubiquitin-protein ligation rates (UbPL) and chymotryptic- and tryptic-like proteasome peptidase activities in porcine skeletal muscle, heart, lung, liver, spleen and kidney (n=5 each). There were considerable differences between tissues (p<0.05 for all parameters). Lung and spleen showed high levels of free and conjugated ubiquitin and high UbPL. Proteasome activities were highest in kidney and heart. There were linear relationships between tryptic-like and chymotryptic-like proteasome peptidase activities (r2 = 0.624, p<0.001) and between free and conjugated ubiquitin tissue levels (r2 = 0.623, p<0.001). Tissue levels of free and conjugated ubiquitin correlated linear with UbPL (p<0.005), but they were not correlated with proteasome peptidase activities. The results suggest that tissue ubiquitin pools are tightly regulated and indicate a constant proportion of conjugated ubiquitin. They further support the hypothesis that ubiquitin-protein ligase systems, and probably deubiquitylating enzymes, are key regulators of ubiquitin homeostasis. The detected differences are suggestive of tissue-specific roles of ubiquitin-proteasome pathway components. Besides the known importance of the ubiquitin proteasome pathway in heart, kidney and the immune system, the results suggest the lung as another organ in which ubiquitin proteasome pathway components may also significantly contribute to disease processes.

• MeSH
• finanční podpora výzkumu jako téma MeSH
• interpretace statistických dat MeSH
• komplexy ubikvitinligas biosyntéza   chemie   MeSH
• prasata fyziologie   MeSH
• tkáňová distribuce fyziologie   účinky léků   MeSH
• tkáňové extrakty chemie   izolace a purifikace   MeSH
• ubikvitin konjugující enzymy biosyntéza   chemie   MeSH
• ubikvitin chemie   MeSH
• western blotting metody   využití   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH