Additional Cell Damage Research Articles

Efficacy and safety of levosimendan in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention: The LEVOCEST trial.

Primary angioplasty is the standard procedure for patients with ST-segment elevation myocardial infarction (STEMI). However, myocardial reperfusion results in additional cell damage. Levosimendan, due to its pleiotropic effects, may be a therapeutic alternative to prevent this damage. The objective of this study was to evaluate whether this drug can reduce infarct size in patients with STEMI. Patients were randomized to receive a 24-h infusion of either levosimendan (0.1 μg/kg/min) or placebo after the primary angioplasty. The main objective was to assess the size of the infarct by cardiac resonance at 30 days and 6 months after the event. Other variables such as left ventricular ejection fraction (LVEF) and adverse ventricular remodeling (AVR) were assessed by speckle-tracking echocardiography and magnetic resonance. Major adverse cardiovascular events (MACE) were also collected. 157 patients were analysed (levosimendan, n = 79; placebo, n = 78). We found that after 6 months, patients treated with levosimendan had a greater reduction in infarct size (13.19% ± 9.5% vs.11.79% ± 9%, p = 0.001), compared with those in the placebo group (13.35% ± 7.1% vs. 13.43% ± 7.8%, p = 0.38). There were no significant differences in MACE between both groups. Levosimendan is a safe and effective therapeutic option for reducing infarct size in patients with STEMI.

Vitrifying expanded equine embryos collapsed by blastocoel aspiration is less damaging than slow-freezing

The cryotolerance of equine blastocysts larger than 300 μm can be improved by aspirating blastocoele fluid prior to vitrification; however, it is not known whether blastocoele aspiration also enables successful slow-freezing. The aim of this study was therefore to determine whether slow-freezing of expanded equine embryos following blastocoele collapse was more or less damaging than vitrification. Grade 1 blastocysts recovered on day 7 or 8 after ovulation were measured (>300–550 μm, n = 14 and > 550 μm, n = 19) and blastocoele fluid was aspirated prior to slow-freezing in 10% glycerol (n = 14), or vitrification (n = 13) in 16.5% ethylene glycol/16.5% DMSO/0.5 M sucrose. Immediately after thawing or warming, embryos were cultured for 24 h at 38 °C and then graded and measured to assess re-expansion. Control embryos (n = 6) were cultured for 24 h following aspiration of blastocoel fluid, without cryopreservation or exposure to cryoprotectants. Subsequently, embryos were stained to assess live/dead cell proportion (DAPI/TOPRO-3), cytoskeleton quality (Phalloidin) and capsule integrity (WGA). For 300–550 μm embryos, quality grade and re-expansion were impaired after slow-freezing but not affected by vitrification. Slow-freezing embryos >550 μm induced additional cell damage as indicated by a significant increase in dead cell proportion and disruption of the cytoskeleton; neither of these changes were observed in vitrified embryos. Capsule loss was not a significant consequence of either freezing method. In conclusion, slow-freezing of expanded equine blastocysts collapsed by blastocoel aspiration compromises post-thaw embryo quality more than vitrification.

Protective Effect of GIP against Monosodium Glutamate-Induced Ferroptosis in Mouse Hippocampal HT-22 Cells through the MAPK Signaling Pathway

The effect of glucose-dependent insulinotropic polypeptide (GIP) on cells under oxidative stress induced by glutamate, a neurotransmitter, and the underlying molecular mechanisms were assessed in the present study. We found that in the pre-treatment of HT-22 cells with glutamate in a dose-dependent manner, intracellular ROS were excessively generated, and additional cell damage occurred in the form of lipid peroxidation. The neurotoxicity caused by excessive glutamate was found to be ferroptosis and not apoptosis. Other factors (GPx-4, Nrf2, Nox1 and Hspb1) involved in ferroptosis were also identified. In other words, it was confirmed that GIP increased the activity of sub-signalling molecules in the process of suppressing ferroptosis as an antioxidant and maintained a stable cell cycle even under glutamate-induced neurotoxicity. At the same time, in HT-22 cells exposed to ferroptosis as a result of excessive glutamate accumulation, GIP sustained cell viability by activating the mitogen-activated protein kinase (MAPK) signalling pathway. These results suggest that the overexpression of the GIP gene increases cell viability by regulating mechanisms related to cytotoxicity and reactive oxygen species production in hippocampal neuronal cell lines.

Effect of pasteurization on Aspergillus fumigatus in apple juice: Analysis of the thermal and electric effects

Fungal spoilage in fruit juices is a currently relevant issue considering that recent reports have found unacceptable fungal levels even after traditional pasteurization processes. Ohmic heating demonstrated to be a good alternative process to conventional pasteurization, as it can promote higher heating rates and additional cell damage in some scenarios (nonthermal effects). However, the application of ohmic processing for fungi inactivation has not been properly investigated. The objective of this study was to analyze the inactivation of Aspergillus fumigatus, a highly distributed fungi species, in apple juice by ohmic and conventional heating at 75, 80, 85, 90 and 94 °C. Predictive primary and secondary models were fitted and the Weibull-Mafart models were the most accurate to describe the experimental behavior considering the statistical indices applied. Statistical differences between both thermal processes were found in the three lower analyzed temperatures (75, 80 and 85 °C), which is possibly related to nonthermal effects. When ohmic heating was applied, processing time was up to 23% shorter. The resulted model was successfully validated in two distinct temperatures (83 and 92 °C) and could be applied to obtain adequate processing times for apple juice pasteurization. This study contributes to deepen the knowledge concerning the use of ohmic heating for fungi inactivation.

Emerging roles of apoptotic microtubules during the execution phase of apoptosis.

Apoptosis is a genetically programmed energy-dependent process of cell demise, characterized by specific morphological and biochemical events in which the activation of caspases has an essential role. During apoptosis the cytoskeleton participates actively in characteristic morphological rearrangements of the dying cell. This reorganisation has been assigned mainly to actinomyosin ring contraction, while microtubule and intermediate filaments are depolymerized at early stages of apoptosis. However, recent reports have showed that microtubules are reformed during the execution phase of apoptosis organizing an apoptotic microtubule network (AMN). AMN is organized behind plasma membrane, forming a cortical structure. Apoptotic microtubules repolymerization takes place in many cell types and under different apoptotic inducers. It has been hypothesized that AMN is critical for maintaining plasma membrane integrity and cell morphology during the execution phase of apoptosis. AMN disorganization leads apoptotic cells to secondary necrosis and the release of potential toxic molecules which can damage neighbor cells and promotes inflammation. Therefore, AMN formation during physiological apoptosis or in pathological apoptosis induced by anti-cancer treatments is essential for tissue homeostasis and the prevention of additional cell damage and inflammation.

Cytoprotective effects of the volatile anesthetic sevoflurane are highly dependent on timing and duration of sevoflurane conditioning: Findings from a human, in-vitro hypoxia model

Using animal models, volatile anesthetics have been recognized for their neuroprotective effects. Nevertheless, there is still disagreement about the optimal duration and timing of conditioning with the volatile anesthetic sevoflurane in the human system. In the study presented, we employed a human neuronal cell culture model to investigate the effects of hypoxia and to evaluate potential cytoprotective properties of different sevoflurane conditioning strategies. Sevoflurane was applied to human IMR-32 cells in which hypoxic conditions were induced for 2 h using our recently described two-enzyme model (Zitta et al., Eur. J. Pharmacol., 2010). Cellular effects of hypoxia and sevoflurane conditioning were evaluated by lactate dehydrogenase (LDH) measurements, brightfield microscopy, ELISAs, cytometric bead arrays, Westernblotting and RT-PCR. Hypoxia increased the release of LDH into the culture medium after 24 h (normoxia: 0.15 ± 0.02 a.u; hypoxia: 0.69 ± 0.08 a.u, P < 0.001) and expression of hypoxia associated genes HIF-1alpha, VEGF, catalase. Cytoprotective effects were observed in cultures that received sevoflurane for 30 min before hypoxia (preconditioning: 0.41 ± 0.07 a.u., P < 0.01) and for 30 min during the hypoxic period (intraconditioning: 0.20 ± 0.01 a.u., P < 0.001). Application of sevoflurane after the hypoxic insult did not lead to cytoprotection (postconditioning: 0.73 ± 0.12 a.u., P > 0.05). Conditioning with sevoflurane for a total of 3 h before, during and after hypoxia, however, resulted in an enhanced release of LDH (periconditioning: 0.97 ± 0.10 a.u., P < 0.01) and additional cell damage. Hypoxia and sevoflurane intraconditioning were associated with changes in erk1/2 phosphorylation (T202/Y204) and HIF-1alpha protein levels, whereas phosphorylation of akt (S473) was not significantly altered. Our results suggest short pre- and intraconditioning with sevoflurane as most potent strategies to reduce hypoxia induced neuronal cell damage.

Clinical and Histopathological Findings after Transpupillary Thermotherapy of Malignant Choroidal Melanoma

Summary Purpose of the study: The purpose of the study was evaluation of effectiveness of diode laser transpupillary thermotherapy and determining in what extent it may act as the only method of therapy of choroidal tumors, and when it should be used in combination with other methods. We evaluated also the effectiveness of transpupillary thermotherapy (TTT) in generating tumor necrosis by light (LM) and electron microscopy (EM), as well as additional cell damage in the area directly adherent to the necrotic zone. Patients and method: 57 eyes of 55 patients aged 31 to 82 years (mean – 55 years) and diagnosed with intraocular tumor were evaluated. The follow-up time ranged from 2 to 25 months. All patients were treated with transpupillary thermotherapy (TTT) using diode laser OcuLight SLx, IRIS Medical Instruments, Inc. Five eyes of five patients were enucleated because of inefficient treatment and three globes were evaluated in regard to effectiveness of TTT by light (LM) and electron microscopy (EM). Results: In 41 cases (72%) of 57 eyes tumor regression, in 7 eyes (12%) stabilization and in 9 (16%) progression was stated. As to complications and side effects visual field scotomas in treated area, hemorrhage to the vitreous, PVR, secondary neovascular glaucoma and exudative retinal detachment were found during the treatment and follow-up. On histopathological examination with an aid of LM we found three zones of changes, but EM revealed additional zone D which was invisible on LM. No scleral alterations induced by heat were found. Conclusions: 1. In selected cases transpupillary thermotherapy (TTT) can be effective especially in regard to small tumors. 2. Treatment of larger tumors should be managed rather in combination with other methods (e.g. 106 Ru) in order to speed-up the treatment and increase the chances for total tumor regression. 3. Depending on clinical image and obtained therapeutic effects the treatment should be multiply repeated. 4. After TTT the cytotoxic effect gradually decreases proportionally to the distance from the central point of the diode laser spot with additional cell damage in the area adjacent to the necrotic zone. 5. The finding of an additional area of seriously injured cells may explain the prolonged time that is needed for tumor regression after TTT and the radiotherapeutic effect on this area in case of simultaneous plaque radiotherapy which may finally result in a deeper tumor necrosis compared to TTT as sole therapy. 6. All complications and side effects stated in the course of treatment were not dangerous to the eye, however in some cases further treatment may be problematic or even impossible.

Additional cell damage after transpupillary thermotherapy in choroidal malignant melanoma.

The aim of this study was to evaluate the effectiveness of transpupillary thermotherapy (TTT) in generating tumour necrosis by light and electron microscopy, as well as to evaluate additional cell damage in the area directly adherent to the necrotic zone. Four eyes of four patients diagnosed with intraocular malignant melanoma of the uvea were treated experimentally with diode laser TTT. In all cases a standard technique was used. All eyes were enucleated: one eye the day after TTT, two eyes 2 days after TTT, and one eye 6 weeks after TTT. Immediately after enucleation the eyes were immersed in standard Karnovsky's fixative with cocodylate buffer and prepared for light and electron microscopy. In the treated area of all four melanomas we found a dense band of necrotic tissue (zone A) consisting of an amorphous mass of dead cells sharply demarcated from the rest of the neoplastic tissue. Next to this zone was a more eosinophilic and also sharply demarcated band (zone B) that consisted of similar but less intensive changes. In the next band (zone C), marked injury to the cellular membrane and subcellular structures were seen on electron microscopy. The next band (zone D) consisted of changes mainly observed only within the cytoplasm of neoplastic cells and significantly less intensive than those in zone C. Outside zone D tumour cells that were normal in appearance were seen. No scleral alterations induced by heat were found. We concluded that after TTT the cytotoxic effect gradually decreases in proportion to the distance from the central point of the diode laser spot, with additional cell damage in the area adjacent to the necrotic zone. The interval between TTT and enucleation had no influence on the histological results.

Effects of organic peroxides on human epidermal keratinocytes

Human epidermal keratinocytes cultured for about 10 days were incubated for 60 min with ferrous ions, ascorbic acid, H 2O 2 t-butyl hydroperoxide or benzoyl peroxide. Lipid peroxidation was determined by malondialdehyde and ethane formation and cytotoxicity by the trypan blue exclusion test. ADP complexed ferrous ions and ascorbic acid led to high lipid peroxidation of keratinocytes, but no cell damage occurred. In contrast, H 2O 2, t-butyl hydroperoxide and benzoyl peroxide were unable to induce lipid peroxidation. Cell viability decreased greatly with benzoyl peroxide. The addition of ferrous ions to keratinocytes incubated with H 2O 2, t-butyl hydroperoxide or benzoyl peroxide resulted in a significant increase in lipid peroxidation whereas only slight additional cell damage occurred. In keratinocytes incubated with benzoyl peroxide and simultaneously irradiated with UV-A, lipid peroxidation increased and was several times higher than with UV-A alone. (+)-Cyanidanol-3 inhibited lipid peroxidation in both systems whereas EDTA was effective only when keratinocytes were exposed to benzoyl peroxide and ferrous ions. The data indicate that in human epidermal keratinocytes lipid peroxidation is inducible, but that it is not related to cell damage. Cytotoxicity caused in keratinocytes by benzoyl peroxide must be due to a mechanism dissimilar to lipid peroxidation.

An ultrastructural study of initial changes in epithelium damaged by surface freezing.

The changes seen in frozen thawed epithelium have been compared with pathological changes occurring under other circumstances. The intact cell membranes, invaginated cells, and varying densities of cell cytoplasm are all compatible with osmotic changes occurring after alteration in cell membrane permeability as is the development of bullae under these conditions. It is suggested, therefore, that this constitutes the major mechanism of cryosurgical attack at these temperatures. The finding that ultrastructural damage was evident very shortly after thawing, implicates changes directly due to freezing and thawing but does not necessarily rule out later additional cell damage occurring in an ischaemic situation.