Evidence for an additional effect of whole-body vibration above resistive exercise alone in preventing bone loss during prolonged bed rest

SUMMARY: The addition of whole-body vibration to high-load resistive exercise may provide a better stimulus for the reduction of bone loss during prolonged bed rest (spaceflight simulation) than high-load resistive exercise alone. INTRODUCTION: Prior work suggests that the addition of whole-body vibration to high-load resistive exercise (RVE) may be more effective in preventing bone loss in spaceflight and its simulation (bed rest) than resistive exercise alone (RE), though this hypothesis has not been tested in humans. METHODS: Twenty-four male subjects as part of the 2nd Berlin Bed Rest Study performed RVE (n = 7), RE (n = 8) or no exercise (control, n = 9) during 60-day head-down tilt bed rest. Whole-body, spine and total hip dual X-ray absorptiometry (DXA) measurements as well as peripheral quantitative computed tomography measurements of the tibia were conducted during bed rest and up to 90 days afterwards. RESULTS: A better retention of bone mass in RVE than RE was seen at the tibial diaphysis and proximal femur (p ≤ 0.024). Compared to control, RVE retained bone mass at the distal tibia and DXA leg sub-region (p ≤ 0.020), but with no significant difference to RE (p ≥ 0.10). RE impacted significantly (p = 0.038) on DXA leg sub-region bone mass only. Calf muscle size was impacted similarly by both RVE and RE. On lumbar spine DXA, whole-body DXA and calcium excretion measures, few differences between the groups were observed. CONCLUSIONS: Whilst further countermeasure optimisation is required, the results provide evidence that (1) combining whole-body vibration and high-load resistance exercise may be more efficient than high-load resistive exercise alone in preventing bone loss at some skeletal sites during and after prolonged bed rest and (2) the effects of exercise during bed rest impact upon bone recovery up to 3 months afterwards

Nicotine and Biochanin A, but Not Cigarette Smoke, Induce Anti-Inflammatory Effects on Keratinocytes and Endothelial Cells in Patients with Behçet's Disease

During periods of smoking, patients with Behçet's disease have less oral aphthae than in abstinence. To elucidate this observation, human keratinocytes and dermal microvascular endothelial cells (HMEC-1) were incubated with serum of 20 patients with Behçet's disease and 20 healthy controls for 4hours. Maximum non-toxic concentrations were determined and the cells were further treated with 6μm nicotine, 3.3% cigarette smoke extract (CES), 100μm biochanin A, and 6.25/12.5μm pyrrolidine dithiocarbamate alone and in combinations for 24hours. Serum IL-8 levels of patients were significantly lower than those of controls. However, after 4hours incubation with patients' sera, IL-8 release by both cell types was markedly increased when compared with the corresponding serum levels. The levels of IL-6 and vascular endothelial growth factor (VEGF) release were after 4hours similar with the corresponding levels in serum. IL-1 was not detected. Nicotine significantly decreased IL-8 and -6 release by HMEC-1 maintained in both patients' and controls' sera, but only IL-6 release by keratinocytes maintained in patients' sera. VEGF release by both cells was markedly increased after nicotine treatment in either serum. CES significantly decreased IL-8 release and increased production of VEGF in keratinocytes maintained in patients' serum. The phytoestrogen biochanin A alone and in combination with nicotine further decreased the secretion of IL-8, -6, and VEGF in all experimental settings. Our data support a specific anti-inflammatory effect of nicotine on keratinocytes and endothelial cells maintained in the serum of patients with Behçet's disease. Moreover, biochanin A is likely to exhibit similar and even more profound results than nicotine