Mitochondria - in the crossfire of SARS-CoV-2 and immunity

The pathophysiology, immune reaction, differential vulnerability of different population groups and viral host immune system evasion strategies of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection are not yet well understood. Here, we reviewed the multitude of known strategies of coronaviruses and other viruses to usurp mitochondria-associated mechanisms involved in the host innate immune response and put them in context with the current knowledge on SARS-CoV-2. We argue that maintenance of mitochondrial integrity is essential for adequate innate immune system responses and to blunt mitochondrial modulation by SARS-CoV-2. Mitochondrial health thus may determine differential vulnerabilities to SARS-CoV-2 infection rendering markers of mitochondrial functions promising potential biomarkers for SARS-CoV-2 infection risk and severity of outcome. Current knowledge gaps on our understanding of mitochondrial involvement in SARS-CoV-2 infection, life-style and pharmacological strategies to improve mitochondrial integrity and potential reciprocal interactions with chronic and age-related diseases, e.g. Parkinson's Disease, are pointed out

The increase in hydric volume is associated to contractile impairment in the calf after the world's most extreme mountain ultra-marathon

Studies have recently focused on the effect of running a mountain ultra-marathon (MUM) and their results show muscular inflammation, damage and force loss. However, the link between peripheral oedema and muscle force loss is not really established. We tested the hypothesis that, after a MUM, lower leg muscles' swelling could be associated with muscle force loss. The knee extensor (KE) and the plantar flexor (PF) muscles' contractile function was measured by supramaximal electrical stimulations, potentiated low- and high-frequency doublets (PS10 and PS100) of the KE and the PF were measured by transcutaneous electrical nerve stimulation and bioimpedance was used to assess body composition in the runners (n\ua0=\ua011) before (Pre) and after (Post) the MUM and compared with the controls (n\ua0=\ua08)

The energetics during the world most challenging mountain ultramarathon: a case study

The energy requirements during ultra-endurance events are likely to be at the extremes ofhuman tolerance (Millet and Millet, 2012). This is of further importance for extreme mountain ultra-marathon (MUM), where the ultra-long distance performance is coupled to run and/or walk on mountain trails with considerable positive and negative elevation change. For instance, it was shown that after the world\u2019s most challenging MUM the energy cost of uphill running decreased, likely due to changes in the uphill-running step mechanics that lead to a \u2018smoother\u2019 and more economical running style (Vernillo et al., 2013). However, that study focused only on longitudinal (i.e., pre-post) changes. Thus, there are few data examining the physiological changes during a MUM with a high fatiguing potential in ecologically valid environments. Accordingly, we report the case of an experienced MUM runner who was participating in the world\u2019s most challenging MUM with the aim to provide the first data about the energy requirements as well as the physiological adaptations of MUM

Changes in spatio-temporal gait parameters and vertical speed during an extreme mountain ultra-marathon

The aim of the present study was to investigate the effects of altitude and distance on uphill vertical speed (VS) and the main spatio-temporal gait parameters during an extreme mountain ultra-marathon. The VS, stride height (SH) and stride frequency (SF) of 27 runners were measured with an inertial sensor at the shank for two different altitude ranges (low 1300-2000\u2005m vs high 2400-3200 m) of 10 mountains passes distributed over a 220\u2005km course. There was a significant interaction (F(4,52)\u2009=\u20094.04, p\u2009<\u20090.01) for the effect of altitude and distance on VS. During the first passes, the mean VS was faster at lower altitudes, but this difference disappeared at a quarter of the race length, suggesting that neuromuscular fatigue influenced the uphill velocity to a larger extent than the oxygen delivery. The average VS, SH and SF were 547\u2009\ub1\u2009135 m/h, 0.23\u2009\ub1\u20090.05 m and 0.66\u2009\ub1\u20090.09 Hz. The individual VS change for each uphill portions was more strongly correlated with the changes in SH (r\u2009=\u20090.80, P\u2009<\u20090.001, n\u2009=\u2009321) than SF (r\u2009=\u20090.43, P\u2009<\u20090.001, n\u2009=\u2009321). This suggests a large effect of the knee extensors strength loss on the diminution of VS