Introduction À l’opposé de la résistance à la perte de poids des obèses, les maigreurs constitutionnelles (MC) ont naturellement un indice de masse corporelle (IMC) bas (13 – 17,5 kg/m2 ) sans ...trouble du comportement alimentaire, ni anomalie biologique ou hormonale, avec des règles conservées, une balance énergétique stable et un profil hormonal anorexigène en image en miroir de l’obésité. Nous avons voulu tester l’hypothèse d’une résistance à la prise de poids chez les MC. Patients et méthodes 10 femmes MC (IMC < 17,5 kg/m2 ) et 10 femmes contrôles (C, IMC : 18,5–23 kg/m2) ont réalisé 4 semaines de surnutrition lipidi que (630kcal), encadrées par 3 bilans (initial, 1 mois et 2 mois) : DXA, PYY, GLP-1, ghréline et obéstatine, au cours d’un repas test, calorimétrie indirecte, génomique sur biopsies musculaire et adipeuse et métabolome urinaire. Résultats Malgré une surnutrition significative et comparable dans les 2 groupes, la prise de poids n’a été significative que chez les C (+ 1 kg) avec une perte de poids significative chez les MC (– 0,370 kg). La surnutrition a entrainé une augmentation significative du métabolisme basal chez les MC uniquement, sans modification significative chez les C, ni modification de l’activité physique dans les 2 groupes. La surnutrition a entrainé une exacerbation du profil anorexigène chez les MC et un profil orexigène chez les C : PYY significativement augmenté chez les MC mais pas chez les C; temps d’exposition post prandial au GLP-1 significativement augmenté chez les MC mais pas chez les C; ghréline, ghréline octanoylée/totale et ghréline/obéstatine significativement augmentés chez les C mais pas chez les MC. Conclusion La surnutrition lipidique de 4 semaines n’a pas permis de faire prendre du poids aux MC mais a entrainé une augmentation du MB et l’exacerbation du profil anorexigène des hormones de la régulation de l’appétit.
Prolonged running is known to induce hemolysis. It has been suggested that hemolysis may lead to a significant loss of red blood cells; however, its actual impact on the erythrocyte pool is unknown. ...Here, we test the hypothesis that prolonged running with high hemolytic potential decreases total red blood cell volume (RCV). Hemolysis (n = 22) and RCV (n = 19) were quantified in ultra‐marathon runners before and after a 166‐km long mountain ultra‐endurance marathon (RUN) with 9500 m of altitude gain/loss. Assessment of total hemoglobin mass (Hbmass) and RCV was performed using a carbon monoxide rebreathing technique. RUN induced a marked acute‐phase response and promoted hemolysis, as shown by a decrease in serum haptoglobin (P < 0.05). Elevated serum erythropoietin concentration and reticulocyte count after RUN were indicative of erythropoietic stimulation. Following RUN, runners experienced hemodilution, mediated by a large plasma volume expansion and associated with a large increase in plasma aldosterone. However, neither Hbmass nor RCV were found to be altered after RUN. Our findings indicate that mechanical/physiological stress associated with RUN promotes hemolysis but this has no impact on total erythrocyte volume. We therefore suggest that exercise ‘anemia’ is entirely due to plasma volume expansion and not to a concomitant decrease in RCV.
Purpose
The effect of trail running competitions on cost of running (Cr) remains unclear and no study has directly examined the effect of distances in similar conditions on Cr. Accordingly, the aims ...of this study were to (i) assess the effect of trail running races of 40–170 km on Cr and (ii) to assess whether the incline at which Cr is measured influences changes in Cr.
Methods
Twenty trail runners completed races of < 100 km (SHORT) and 26 trail runners completed races of > 100 km (LONG) on similar courses and environmental conditions. Oxygen uptake, respiratory exchange ratio, ventilation, and blood lactate were measured before and after the events on a treadmill with 0% (FLAT) and 15% incline (UH) and Cr was calculated.
Results
Cr increased significantly after SHORT but not LONG races. There was no clear relationship between changes in Cr and changes in ventilation or blood lactate. There was a significant correlation (
r
= 0.75,
p
< 0.01) between changes in FLAT and UH Cr, and the change in Cr was not affected by the incline at which Cr was measured.
Conclusion
The distance of the trail running race, but not the slope at which it is measured, influence the changes in Cr with fatigue. The mechanism by which Cr increases only in SHORT is not related to increased cost of breathing.
Application of non-invasive ventilation (NIV) during exercise improves exercise tolerance in severe COPD patients; however, the underlying mechanism is only partially unraveled. As part of its known ...effect to unload the respiratory muscles, we looked for the influence of NIV on post-exercise quadriceps muscle endurance.
We included 25 severe COPD patients entering an outpatient pulmonary rehabilitation program. They performed, on successive days, three quadriceps endurance tests at 70% of the maximal strength (1RM) to task failure (TlimQ); 1) control condition; 2) following constant load cycling exercise to exhaustion without Inspiratory Pressure Support (TlimQ IPS-); 3) following the same cycling exercise with IPS (TlmQ IPS+).
Dyspnea Borg score was significantly reduced at the end of the constant load cycling exercise with IPS+ compared to IPS- (3.5±2.6 to 4.3±2.3, p<0.05). Compared to controlled condition, TlimQ was reduced from 78.9±22.7 s to 64.7±22.1 s (p<0.01) with IPS+ and to 48.9±13.7 s (p<0.001) with IPS-. Sensitive analysis revealed a positive effect of NIV on TlimQ in only 15 of the 25 included patients (60%) and was unpredictable from exercise tolerance or maximal quadriceps strength.
Using a simple muscle endurance test, we showed the protective effect of NIV on the exercise-induced quadriceps dysfunction. This beneficial effect is inconstant in our small series of patients and could not be predicted by exercise capacity or endurance to exercise. However, measuring quadriceps muscle endurance following a session of exercise could determine in which patient NIV would improve the benefit of pulmonary rehabilitation.
Aim
Constitutional thinness (CT) is a rare condition of natural low body weight, with no psychological issues, no marker of undernutrition and a resistance to weight gain. This study evaluated the ...skeletal muscle phenotype of CT women by comparison with a normal BMI control group.
Methods
Ten CT women (BMI < 17.5 kg/m2) and 10 female controls (BMI: 18.5‐25 kg/m2) underwent metabolic and hormonal assessment along with muscle biopsies to analyse the skeletal muscular fibres pattern, capillarity, enzymes activities and transcriptomics.
Results
Constitutional thinness displayed similar energy balance metabolic and hormonal profile to controls. Constitutional thinness presented with lower mean area of all the skeletal muscular fibres (−24%, P = .01) and percentage of slow‐twitch type I fibres (−25%, P = .02, respectively). Significant downregulation of the mRNA expression of several mitochondrial‐related genes and triglycerides metabolism was found along with low cytochrome c oxidase (COX) activity and capillary network in type I fibres. Pre‐ and post‐mitochondrial respiratory chain enzymes levels were found similar to controls. Transcriptomics also revealed downregulation of cytoskeletal‐related genes.
Conclusion
Diminished type I fibres, decreased mitochondrial and metabolic activity suggested by these results are discordant with normal resting metabolic rate of CT subjects. Downregulated genes related to cytoskeletal proteins and myocyte differentiation could account for CT's resistance to weight gain.
Neurologic and muscular damage associated with acute hepatitis due to hepatitis E virus (HEV) are rare and may be underdiagnosed.
We report the case of a 56-year-old man, presenting with flaccid ...tetraparesis secondary to an acute rhabdomyolysis induced by acute E virus hepatitis. He fully recovered after one month under supportive treatment.
Rare cases of acute rhabdomyolysis induced by HEV infection have been reported in the literature. We discuss the potential adjuvant role of statin treatment in our patient. Unexplained acute neurological conditions should prompt the search for HEV infection.
Pompe disease (PD) is caused by a deficiency of lysosomal acid α-glucosidase resulting from mutations in the
GAA
gene. The clinical spectrum ranges from a rapidly fatal multisystemic disorder ...(classic PD, onset < 1 year) to a milder adult onset myopathy. The aims of this study were to characterize the
GAA
mutations, to establish the disease epidemiology, and to identify potential genotype-phenotype correlations in French late-onset PD patients (onset ≥ 2 years) diagnosed since the 1970s. Data were collected from the two main laboratories involved in PD diagnosis and from the French Pompe registry. Two hundred forty-six patients (130 females and 116 males) were included, with a mean age at diagnosis of 43 years. Eighty-three different mutations were identified in the
GAA
gene, among which 28 were novel. These variants were spread all over the sequence and included 42 missense (one affecting start codon), 8 nonsense, 15 frameshift, 14 splice mutations, 3 small in-frame deletions, and one large deletion. The common c.-32-13T>G mutation was detected in 151/170 index cases. Other frequent mutations included the exon 18 deletion, the c.525del, and the missense mutations c.1927G>A (p.Gly643Arg) and c.655G>A (p.Gly219Arg). Patients carrying the c.-32-13T>G mutation had an older mean age at onset than patients non-exhibiting this mutation (36 versus 25 years). Patients with the same genotype had a highly variable age at onset. We estimated the frequency of late-onset PD in France around 1/69,927 newborns. In conclusion, we characterized the French cohort of late-onset PD patients through a nationwide study covering more than 40 years.
The purpose of this study was to examine the physiological and biological factors associated with ultra‐endurance performance. Fourteen male runners volunteered to run on a treadmill as many ...kilometers as possible over a 24‐h period (24TR). Maximal oxygen uptake (V̇O2max), velocity associated with V̇O2max () and running economy (RE) at 8 km/h were measured. A muscle biopsy was also performed in the vastus lateralis muscle. The subjects ran 149.2 ± 15.7 km in 18 h 39 ± 41 min of effective attendance on the treadmill, corresponding to 39.4 ± 4.2% of . Standard multiple‐regression analysis showed that performance was significantly (R2=0.82; P=0.005) related to V̇O2max and specific endurance, i.e. the average speed sustained over the 24TR expressed in . V̇O2max was associated with a high capillary tortuosity (R2=0.66; P=0.01). Specific endurance was significantly related to RE and citrate synthase activity. It is concluded that a high V̇O2max and an associated developed capillary network are essential for ultra‐endurance running performance. The ability to maintain a high %V̇O2max over a 24TR is another factor associated with performance and is mainly related to RE and high mitochondrial oxidative capacity in the vastus lateralis.
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