Acute exercise-induced glycocalyx shedding does not differ between exercise modalities,but is associated with total antioxidative capacity

ObjectivesRegular physical exercise is known to protect endothelial integrity. It has been proposed that acute exercise-induced changes of the (anti-)oxidative system influence early (glycocalyx shedding) and sustained endothelial activation (shedding of endothelial cells, ECs) as well as endothelial-cell repair by circulating hematopoietic stem and progenitor cells (HPCs). However, results are not conclusive and data in trained participants performing different exercise modalities is lacking.DesignEighteen healthy, well-trained participants (9 runners, 9 cyclists; age: 29.7 ± 4.2 yrs) performed a strenuous acute exercise session consisting of 4 bouts of 4-min high-intensity with decreasing power profile and 3-min low-intensity in-between.MethodsAverage power/speed of intense phases was 85% of the peak achieved in a previous incremental test. Before and shortly after exercise, total oxidative and antioxidative capacities (TAC), shedding of syndecan-1, heparan sulfate, hyaluronan, ECs, and circulating HPCs were investigated.ResultsTAC decreased from 1.81 ± 0.42 nmol/L to 1.47 ± 0.23 nmol/L post-exercise (p = 0.010) only in runners. Exercise-induced early and sustained endothelial activation were enhanced post-exercise- syndecan-1: 103.2 ± 63.3 ng/mL to 111.3 ± 71.3 ng/mL, heparan sulfate: from 2637.9 ± 800.1 ng/mL to 3197.1 ± 1416.3 ng/mL, both p < 0.05; hyaluronan: 84.3 ± 21.8 ng/mL to 121.4 ± 29.4 ng/mL, ECs: from 6.6 ± 4.5 cells/μL to 9.5 ± 6.2 cells/μL, both p < 0.01; results were not different between exercise modalities and negatively related to TAC concentrations post-exercise. HPC proportions and self-renewal ability were negatively, while EC concentrations were positively associated with circulating hyaluronan concentrations.ConclusionsThese results highlight the importance of the antioxidative system to prevent the endothelium from acute exercise-induced vascular injury – independent of exercise modality – in well-trained participants. Endothelial-cell repair is associated with hyluronan signaling, possibly a similar mechanism as in wound repair.     

Long-Term Enteral Feeding: A Retrospective Comparison of Delivery via Percutaneous Endoscopic Gastrostomy and Nasoenteric Tubes

The use of percutaneous endoscopic gastrostomy (PEG) tubes for enteral feeding is widespread, although their superiority to other feeding devices, such as nasoenteric tubes (NET), has not been substantiated. We retrospectively compared clinical outcomes in patients who received enteral feeding via PEG (n = 80) or NET (n = 29) from 1984 to 1988. Mean follow-up was 192 days in the PEG group and 141 days in the NET group. Changes in nutritional and performance status were similar in both groups. Aspiration pneumonia occurred within 14 days of tube placement in 6% and 24% (p = 0.01) of the PEG and NET patients, respectively. With the exception of tube replacement, cumulative rates of minor and major complications (including aspiration pneumonia) were similar in both groups during follow-up. None of the clinical variables that were assessed correlated with the development of aspiration pneumonia. Mortality was similar in both groups. These results suggest that, for long-term enteral feeding, PEG offers no substantial advantages over NET with respect to patient nutrition, performance, or survival. The reasons for the observed difference in short-term aspiration pneumonia rates are unknown, and must be investigated prospectively.     

Cloned manganese superoxide dismutase reduces oxidative stress in Escherichia coli and Anacystis nidulans.

The Mn superoxide dismutase gene of Escherichia coli was subcloned into the E. coli-Anacystis nidulans shuttle vector pSG111 to make the plasmid pMYG1. Transformation of E. coli HB101 with pMYG1 resulted in a 6-fold increase in superoxide dismutase activity. There was also induction of Mn superoxide dismutase in the transformants upon exposure to paraquat, as evidenced by dramatically increased levels of the Mn superoxide dismutase polypeptide in cytoplasmic extracts and a 16-fold further increase in superoxide dismutase activity. As well, the E. coli transformants showed resistance to paraquat-mediated inhibition of growth. Anacystis nidulans, a cyanobacterium that has no detectable Mn superoxide dismutase and is, consequently, very sensitive to oxidative stress, was also transformed with pMYG1. The transformants had detectable levels of Mn superoxide dismutase protein and showed resistance to paraquat-mediated inhibition of growth and photobleaching of pigments. Paraquat is known to promote formation of the superoxide radical anion, O2-., and thus the data have been interpreted as indicating that the cloned Mn superoxide dismutase provides protection in both E. coli and A. nidulans against damage attributable to O2-..