Study of the systemic and pulmonary oxidative stress status during exposure to propofol and sevoflurane anaesthesia during thoracic surgery: Retracted:

Sevoflurane Affects Oxidative Stress and Alters Apoptosis Status in Children and Cultured Neural Stem Cells

Anesthesia-induced neurotoxicity in immature animals has raised concerns about similar effects occurring in young children. Our study investigated two commonly used anesthetics-sevoflurane and propofol-for neurotoxicity in young children. Forty-seven children (aged 12-36 months) undergoing hypospadias repair surgery were randomized to receive sevoflurane (SG, n = 24) or propofol (PG, n = 23) general anesthesia. Venous blood was collected at three different times-immediately after induction, 2 h, and 3 days after surgery. The cellular portion was assessed for antioxidant defense and DNA damage, using enzyme assay kits and qRT-PCR, respectively, while serum was used to treat cultured neural stem cells (NSCs). MTT assay and TUNEL staining were performed, and the mRNA levels of antioxidant enzymes and apoptosis indicators were evaluated by qRT-PCR. Antioxidant defense and apoptosis status in the SG group were significantly higher than in the PG group at 2 h after surgery. Additionally, exposure of NSCs to postoperative serum of the SG group resulted in decreased cell density and viability, increased TUNEL-positive cells, elevated mRNA levels of antioxidant enzymes, and cleaved caspase-3 expression. Our data shows for the first time that in young children, administration of sevoflurane, but not propofol, leads to temporally increased antioxidant defense and apoptosis status as well as damage of NSCs.

The volatile anesthetic sevoflurane attenuates ventilator-induced lung injury through inhibition of ERK1/2 and Akt signal transduction

Background

Ventilator-induced lung injury (VILI) sustained during mechanical ventilator support is still a cause of a high rate of morbidity and mortality in intensive care units and in operating rooms. VILI is characterized by pulmonary inflammation that appears to be mediated by proinflammatory cytokines. This study investigates whether the volatile anesthetic sevoflurane has an anti-inflammatory effect that attenuates VILI.

Methods

Twenty one male rabbits were anesthetized and were mechanically ventilated with 50% oxygen at a peak inspiratory pressure (PIP) of 10 cmH₂O, I : E ratio of 1 : 4, and positive end expiratory pressure of 5 cmH₂O. All animals were randomly assigned to one of three groups that were ventilated for 5 h with 10 cmH₂O of PIP (Sham group, n = 7); 30 cmH₂O of PIP (Control group, n = 7); or 30 cmH₂O of PIP and 0.8 vol% sevoflurane (Sevoflurane group, n = 7). The wet/dry weight (W/D) ratio and histopathology of the lung; concentration of interleukin-8 (IL-8) in the bronchoalveolar lavage fluid; and activation of extracellular signal-regulated kinases (ERK) 1/2, p38 mitogen-activated protein kinase, and Akt were measured in the lung tissue after completing the protocol.

Results

Histopathology indicated that the sevoflurane group showed fewer inflammatory cells and architectural changes than the control group did. The W/D ratio [(5.36 ± 0.13) versus (6.61 ± 0.20)], expression of IL-8 [(144.08 ± 14.61) versus (228.56 ± 15.13) pg/ml] and phosphorylation of ERK1/2 and Akt decreased significantly in the sevoflurane group relative to the control group.

Conclusions

Sevoflurane attenuates VILI in rabbits mainly by inhibiting expression of IL-8, and Sevoflurane-induced inhibition of phosphorylated ERK1/2 and Akt might be a possible pathway for protection.

Effect of propofol on hypoxia re-oxygenation induced neuronal cell damage in vitro*

Propofol may protect neuronal cells from hypoxia re-oxygenation injury, possibly via an antioxidant actions under hypoxic conditions. This study investigated the molecular effects of propofol on hypoxia-induced cell damage using a neuronal cell line. Cultured human IMR-32 cells were exposed to propofol (30 μm) and biochemical and molecular approaches were used to assess cellular effects. Propofol significantly reduced hypoxia-mediated increases in lactate dehydrogenase, a marker of cell damage (mean (SD) for normoxia: 0.39 (0.07) a.u.; hypoxia: 0.78 (0.21) a.u.; hypoxia+propofol: 0.44 (0.17) a.u.; normoxia vs hypoxia, p<0.05; hypoxia vs hypoxia+propofol, p<0.05), reactive oxygen species and hydrogen peroxide. Propofol also diminished the morphological signs of cell damage. Increased amounts of catalase, which degrades hydrogen peroxide, were detected under hypoxic conditions. Propofol decreased the amount of catalase produced, but increased its enzymatic activity. Propofol protects neuronal cells from hypoxia re-oxygenation injury, possibly via a combined direct antioxidant effect along with induced cellular antioxidant mechanisms.

Retracted publications in the drug literature

Recent studies have suggested an increase in the number of retracted scientific publications. It is unclear how broadly the issue of misleading and fraudulent publications pertains to retractions of drug therapy studies. Therefore, we sought to determine the trends and factors associated with retracted publications in drug therapy literature. A PubMed search was conducted to identify retracted drug therapy articles published from 2000-2011. Articles were grouped according to reason for retraction, which was classified as scientific misconduct or error. Scientific misconduct was further divided into data fabrication, data falsification, questions of data veracity, unethical author conduct, and plagiarism. Error was defined as duplicate publication, scientific mistake, journal error, or unstated reasons. Additional data were extracted from the retracted articles, including type of article, funding source, author information, therapeutic area, and retraction issue. A total of 742 retractions were identified from 2000-2011 in the general biomedical literature, and 102 drug studies met our inclusion criteria. Of these, 73 articles (72%) were retracted for a reason classified as scientific misconduct, whereas 29 articles (28%) were retracted for error. Among the 73 articles classified as scientific misconduct, those classified as unethical author conduct (32 articles [44%]) and data fabrication (24 articles [33%]) constituted the majority. The median time from publication of the original article to retraction was 31 months (range 1-130). Fifty percent of retracted articles did not state a funding source, whereas pharmaceutical manufacturer funding accounted for only 13 articles (13%) analyzed. Many retractions were due to repeat offenses by a small number of authors, with nearly 40% of the retracted studies associated with two individuals. We found that a greater proportion of drug therapy articles were retracted for reasons of misconduct and fraud compared with other biomedical studies. It is important for health care practitioners to monitor the literature for retractions so that recommendations for drug therapy and patient management may be modified accordingly.

Influence of propofol and volatile anaesthetics on the inflammatory response in the ventilated lung

BACKGROUND

The immunomodulatory effects of volatile anaesthetics in vitro and the protective effect of propofol in lung injury spurred us to study the effects of volatile anaesthetics and propofol on lung tissue in vivo.

METHODS

Twenty-seven pigs were randomized to 4-h general anaesthesia with propofol (8 mg/kg/h, group P, n=9), sevoflurane [minimum alveolar concentration (MAC)=1.0, group S, n=9) or desflurane (MAC=1.0, group D, n=9). Four healthy animals served as the no-ventilation group. Bronchoalveolar lavage fluid (BALF) was obtained to measure the cell counts, platelet-activating factor acetylhydrolase (PAF-AcH), phospholipase A(2) (PLA(2)) and superoxide dismutase (SOD) activity. Lung tissues were evaluated histologically and for caspase-3 expression.

RESULTS

Volatile anaesthetics reduced PAF-AcH levels without affecting PLA(2) activity and resulted in decreased alveolar macrophage and increased lymphocyte counts in BALF (sevoflurane: 29 ± 23%; desflurane: 26 ± 6%, both P<0.05 compared with 4 ± 2% in the no-ventilation group). These findings were accompanied by atelectasis and inflammatory cells' infiltration in the inhalational anaesthetics groups. Also, sevoflurane reduced SOD activity and both sevoflurane and desflurane induced significant caspase-3 expression. In contrast, propofol resulted in a minor degree of inflammation and preserved BALF cells' composition without triggering apoptosis.

CONCLUSION

Halogenated anaesthetics seem to trigger an immune lymphocytic response in the lung, inducing significant apoptosis and impairment of PAF-AcH. In contrast, propofol preserves anti-inflammatory and anti-oxidant defences during mechanical ventilation, thus preventing the emergence of apoptosis.