Oxidative Stress and Mitochondrial Functions in the Intestinal Caco-2/15 Cell Line

Although mitochondrial dysfunction and oxidative stress are central mechanisms in various pathological conditions, they have not been extensively studied in the gastrointestinal tract, which is known to be constantly exposed to luminal oxidants from ingested foods. Key among these is the simultaneous consumption of iron salts and ascorbic acid, which can cause oxidative damage to biomolecules.The objective of the present work was to evaluate how iron-ascorbate (FE/ASC)-mediated lipid peroxidation affects mitochondrion functioning in Caco-2/15 cells. Our results show that treatment of Caco-2/15 cells with FE/ASC (0.2 mM/2 mM) (1) increased malondialdehyde levels assessed by HPLC; (2) reduced ATP production noted by luminescence assay; (3) provoked dysregulation of mitochondrial calcium homeostasis as evidenced by confocal fluorescence microscopy; (4) upregulated the protein expression of cytochrome C and apoptotic inducing factor, indicating exaggerated apoptosis; (5) affected mitochondrial respiratory chain complexes I, II, III and IV; (6) elicited mtDNA lesions as illustrated by the raised levels of 8-OHdG; (7) lowered DNA glycosylase, one of the first lines of defense against 8-OHdG mutagenicity; and (8) altered the gene expression and protein mass of mitochondrial transcription factors (mtTFA, mtTFB1, mtTFB2) without any effects on RNA Polymerase. The presence of the powerful antioxidant BHT (50 microM) prevented the occurrence of oxidative stress and most of the mitochondrial abnormalities.Collectively, our findings indicate that acute exposure of Caco-2/15 cells to FE/ASC-catalyzed peroxidation produces harmful effects on mitochondrial functions and DNA integrity, which are abrogated by the powerful exogenous BHT antioxidant. Functional derangements of mitochondria may have implications in oxidative stress-related disorders such as inflammatory bowel diseases

Technical-Induced Hemolysis in Patients with Respiratory Failure Supported with Veno-Venous ECMO – Prevalence and Risk Factors

The aim of the study was to explore the prevalence and risk factors for technical-induced hemolysis in adults supported with veno-venous extracorporeal membrane oxygenation (vvECMO) and to analyze the effect of hemolytic episodes on outcome. This was a retrospective, single-center study that included 318 adult patients (Regensburg ECMO Registry, 2009–2014) with acute respiratory failure treated with different modern miniaturized ECMO systems. Free plasma hemoglobin (fHb) was used as indicator for hemolysis. Throughout a cumulative support duration of 4,142 days on ECMO only 1.7% of the fHb levels were above a critical value of 500 mg/l. A grave rise in fHb indicated pumphead thrombosis (n = 8), while acute oxygenator thrombosis (n = 15) did not affect fHb. Replacement of the pumphead normalized fHb within two days. Neither pump or cannula type nor duration on the first system was associated with hemolysis. Multiple trauma, need for kidney replacement therapy, increased daily red blood cell transfusion requirements, and high blood flow (3.0–4.5 L/min) through small-sized cannulas significantly resulted in augmented blood cell trauma. Survivors were characterized by lower peak levels of fHb [90 (60, 142) mg/l] in comparison to non-survivors [148 (91, 256) mg/l, p≤0.001]. In conclusion, marked hemolysis is not common in vvECMO with modern devices. Clinically obvious hemolysis often is caused by pumphead thrombosis. High flow velocity through small cannulas may also cause technical-induced hemolysis. In patients who developed lung failure due to trauma, fHb was elevated independantly of ECMO. In our cohort, the occurance of hemolysis was associated with increased mortality