No abstract

Apoptosis or programmed cell death is a process of fundamental importance for regulation of the immune response. Several reasons suggest that apoptosis is involved in exercise-induced alterations of the immune system such as postexercise lymphocytopenia. Healthy volunteers performed two treadmill exercise tests; the first was performed at 80% maximal oxygen uptake until exhaustion (exhaustive exercise) and the second 2 wk later at 60% maximal oxygen uptake with the identical running time (moderate exercise). Blood samples were taken before, immediately after, and 1 h after the test. Lymphocytes were analyzed for apoptotic and necrotic cells by using FITC-labeled annexin V-antibodies and nuclear propidium iodide uptake, respectively. In addition, apoptotic/necrotic cells were measured after a 24-h incubation of lymphocytes in the presence of camptothecin or phytohemagglutinin. Finally, plasma membrane expression of CD95-receptor and CD95-receptor ligand was investigated. Immediately after the exhaustive exercise, the percentage of apoptotic cells increased significantly, whereas it remained unchanged after the moderate exercise. Similar results were obtained after 24-h incubation of lymphocytes in medium alone or in the presence of camptothecin, but not with phytohemagglutinin. We found an upregulation of CD95-receptor expression after both exercise tests. However, only after exhaustive exercise a characteristic shift in CD95 expression profile toward cells with a high receptor density was observed. Expression of the CD95-receptor ligand remained unchanged after both exhaustive and moderate exercise. These results suggest that apoptosis may contribute to the regulation of the immune response after exhaustive exercise. Whether this mechanism can be regarded either as beneficial, i.e., deletion of autoreactive cells, or harmful, i.e., suppression of the immune response, awaits further investigations.

No abstract

Endurance exercise like a marathon is able to induce apoptosis in lymphocytes. Thereby, apoptosis sensitivity seems to be related to training status in an inverse relationship. The increased expression levels of death receptors and ligands might indicate the high apoptosis inducing potential of this type of exercise.

White blood cells (WBCs) express tens of thousands of genes, whose expression levels are modified by genetic and external factors. The purpose of the present study was to investigate the effects of acute exercise on gene expression profiles (GEPs) of WBCs and to identify suitable genes that may serve as surrogate markers for monitoring exercise and training load. Five male participants performed an exhaustive treadmill test (ET) at 80% of their maximal O(2) uptake (Vo(2 max)) and a moderate treadmill test (MT) at 60% Vo(2 max) for exactly the same time approximately 2 wk later. WBCs were isolated by the erythrocyte lysis method. GEPs were measured using the Affymetrix GeneChip technology. After scaling, normalization, and filtering, groupwise comparisons of gene expression intensities were performed, and several measurements were validated by real-time PCR. We found 450 genes upregulated and 150 downregulated (>1.5-fold change; ANOVA with Benjamini-Hochberg correction, P < 0.05) after ET that were closely associated with the gene ontology lists "response to stress" and "inflammatory response". Analysis of mean expression levels after MT showed that the extent of up- and downregulation was workload dependent. The genes for the stress (heat shock) proteins HSPA1A and HSPH1 and for the matrix metalloproteinase MMP-9 showed the most prominent increases, whereas the YES1 oncogene (YES1) and CD160 (BY55) were most strongly reduced. Despite different methodological approaches used, the consistency of our results with the expression data of another study (Connolly PH, Caiozzo VJ, Zaldivar F, Nemet D, Larson J, Hung SP, Heck JD, Hatfield GW, Cooper DM. J Appl Physiol 97: 1461-1469, 2004) suggests that expression fingerprints are useful tools for monitoring exercise and training loads and thereby help to avoid training-associated health risks.