Ruddy Richard

Background/Objectives: An increasing number of apparently healthy individuals are adhering to a gluten-free lifestyle without any underlying medical indications, although the evidence for the health benefits in these individuals remains unclear. Although it has already been shown that a low- or gluten-free diet alters the gut microbiota, few studies have examined the effects of this diet on healthy subjects. Therefore, our aim was to evaluate whether and how a prolonged low-gluten diet impacts gut microbiota composition and function in healthy adults, bearing in mind its intimate link to the host’s health. Methods: Forty healthy volunteers habitually consuming a gluten-containing diet (HGD, high-gluten diet) were included in a randomised control trial consisting of two successive 8-week dietary intervention periods on a low-gluten diet (LGD). After each 8-week period, gut microbiota composition was assessed by 16S rRNA gene sequencing, molecular quantification by qPCR, and a cultural approach, while its metabolic capacity was evaluated through measuring faecal fermentative metabolites by ¹H NMR. Results: A prolonged period of LGD for 16 weeks reduced gut microbiota richness and decreased the relative abundance of bacterial species with previously reported potential health benefits such as Akkermansia muciniphila and Bifidobacterium sp. A decrease in certain plant cell wall polysaccharide-degrading species was also observed. While there was no major modification affecting the main short-chain fatty acid profiles, the concentration of the intermediate metabolite, ethanol, was increased in faecal samples. Conclusions: A 16-week LGD significantly altered both composition and metabolic production of the gut microbiota in healthy individuals, towards a more dysbiotic profile previously linked to adverse effects on the host’s health. Therefore, the evaluation of longer-term LDG would consolidate these results and enable a more in-depth examination of its impact on the host’s physiology, immunity, and metabolism.

Cachexia is a complex syndrome that is often associated with cancer. Chemotherapy, one of the main cancer treatments, worsens weight loss in cancer-induced cachexia. In this context, it is thought that fat loss precedes muscle loss, and that alterations in adipose tissue are associated with tumours. However, the effect of cancer treatment on adipose tissue is not well understood. This study aimed to evaluate the impact of chemotherapy alone on mature 3T3-L1 adipocytes to identify the mechanisms contributing to adipose tissue alteration. The murine cell line 3T3-L1, a model of mature adipocytes, was used in this study. After differentiation, cells were treated for 48 h with a chemotherapy cocktail called FLOT composed of 5-fluorouracil, leucovorin, oxaliplatin and docetaxel at two concentrations (FLOT 1X and 0.1X). The control group was treated with the vehicle of the chemotherapy cocktail. Viability, mitochondrial function and dynamics, lipid metabolism, and cellular stress were also evaluated. FLOT 1X chemotherapy significantly reduced viability of mature 3T3-L1 cells and inhibited lipid accumulation. Interestingly, while FLOT 1X treatment downregulated lipogenesis markers, FLOT 0.1X treatment upregulated some of them. Although, the treatment showed no effect on mitochondrial respiration or density, it significantly increased expression of oxidative stress and inflammation markers in adipocytes.This in vitro study provides the first evidence of FLOT chemotherapy's direct effects on healthy mature adipocytes. The results demonstrate significant treatment-induced reductions in cell viability along with dysregulation of both lipogenic and lipolytic pathways. These findings elucidate previously unrecognized mechanisms underlying adipose tissue dysfunction in cancer cachexia.

Adipose tissue (AT), is a major endocrine organ that plays a key role in health and disease. However, adipose dysfunctions, especially altered energy metabolism, have been under‐investigated as white adipocytes have relatively low mitochondrial density. Nevertheless, recent studies suggest that mitochondria could play a major role in AT disorders and that AT mitochondrial activity could depend on adiposity level and location. This clinical study aimed to evaluate mitochondrial respiration and metabolism in human visceral (vAT) and subcutaneous (scAT) AT and their relationship with body mass index (BMI). This clinical study enrolled 67 patients (30 females/37 males) scheduled for digestive surgery without chemotherapy and parietal infection. BMI ranged from 15.4 to 51.9 kg·m ⁻² and body composition was estimated by computed tomographic images. Mitochondrial respiration was measured in situ in digitonin‐permeabilized AT using high‐resolution respirometry and a substrate/inhibitor titration approach. Protein levels of mitochondrial and lipid metabolism key elements were evaluated by Western blot. Maximal mitochondrial respiration correlated negatively with BMI ( p < .01) and AT area ( p < .001) regardless of the anatomical location. However, oxidative phosphorylation respiration was significantly higher in vAT (2.22 ± 0.15 pmol·sec ⁻¹ ·mg ⁻¹ ) than scAT (1.79 ± 0.17 pmol·sec ⁻¹ ·mg ⁻¹ ) ( p < 0.001). In line with oxygraphy results, there were higher levels of mitochondrial respiratory chain complexes in low‐BMI patients and vAT. Mitochondrial respiration decreased with increasing BMI in both scAT and vAT, without sex‐associated difference. Mitochondrial respiration appeared to be higher in vAT than scAT. These differences were both qualitative and quantitative. Clinical Trials Registration ID NCT05417581.

Introduction Cachexia is strongly associated with digestive cancers, particularly oesogastric cancer. Mitochondria in adipose tissue are involved in the regulation of metabolism and physiopathology of cancer cachexia in animal studies. Chemotherapeutic regimens used to control tumour development could also alter mitochondrial function in adipose tissue. We hypothesise that cachexia induces an increase in adipose tissue mitochondrial energy metabolism and that chemotherapy can mitigate this. The purpose of the ChiFMeOE study is to identify adipocyte factors involved in the energy imbalance associated with the cachectic process and their response to chemotherapeutic treatments in patients with oesogastric cancer. Methods and analysis ChiFMeOE is a single-centre observational study that will prospectively include 60 patients referred to chemotherapy and surgery for oesophageal and gastro-oesophageal junction adenocarcinomas at the University Hospital of Clermont-Ferrand, France. Visceral and subcutaneous adipose tissue biopsies will be collected during surgery scheduled before and after neoadjuvant chemotherapy administration, as well as cachexia and nutritional assessment. The primary outcome is the maximum mitochondrial respiration rate (Vmax) measured by high-resolution respirometry. Secondary outcomes are other mitochondrial parameters (ie, enzymatic activities, proteins content and gene expression), tumour characteristics, nutritional status and body composition. Ethics and dissemination The study was approved by an independent institutional review board on June 2023 (Comité de protection des personnes Sud-Méditerranée V; 2023-A00582-43) and declared to the French regulatory authority for research. Written informed consent will be obtained prior to patient inclusion. The principal investigator will be notified of any changes in patient’s health status requiring a modification of his management and/or treatment during the course of the protocol. Results will be published in peer-reviewed journals. Trial registration number ClinicalTrials.gov, NCT05954117.

As older adults tend to reduce their intake of animal-source proteins, plant-source proteins may offer valuable resources for better protein intake. The aim of this study was to assess whether the pea proteins can be used to achieve blood amino acid levels that stimulate muscle protein synthesis. We measured variations in plasma amino acid concentrations in young and older adults given pea (NUTRALYS^® S85 Plus) or whey proteins either alone or in a standardized meal. The effect of amino acid concentrations on protein synthesis in C2C12 myotubes was determined. In terms of results, plasma amino acid concentrations reflected the difference between the amino acid contents of whey and pea proteins. Blood leucine showed a greater increase of 91 to 130% with whey protein compared to pea protein, while the opposite was observed for arginine (A greater increase of 147 to 210% with pea compared to whey). Culture media prepared with plasmas from the human study induced age-dependent but not protein-type-dependent changes in myotube protein synthesis. In conclusion, pea and whey proteins have the same qualities in terms of their properties to maintain muscle protein synthesis. Pea proteins can be recommended for older people who do not consume enough animal-source proteins.

Background: Cardiovascular comorbidities are increasingly being recognised in early stages of chronic obstructive pulmonary disease (COPD) yet complete cardiorespiratory functional assessments of individuals with mild COPD or presenting with COPD risk factors are lacking. This paper reports on the effectiveness of the cardiocirculatory-limb muscles oxygen delivery and utilisation axis in smokers exhibiting no, or mild to moderate degrees of airflow obstruction using standardised cardiopulmonary exercise testing (CPET). Methods: Post-bronchodilator spirometry was used to classify participants as ‘ever smokers without’ (n=88), with ‘mild’ (n=63) or ‘mild-moderate’ COPD (n=56). All underwent CPET with continuous concurrent monitoring of oxygen uptake (V’O₂) and of bioimpedance cardiac output (Qc) enabling computation of arteriovenous differences (a-vO₂). Mean values of Qc and a-vO₂ were mapped across set ranges of V’O₂ and Qc isolines to allow for meaningful group comparisons, at same metabolic and circulatory requirements. Results: Peak exercise capacity was significantly reduced in the ‘mild-moderate COPD’ as compared with the two other groups who showed similar pulmonary function and exercise capacity. Self-reported cardiovascular and skeletal muscle comorbidities were not different between groups, yet disease impact and exercise intolerance scores were three times higher in the ‘mild-moderate COPD’ compared with the other groups. Mapping of exercise Qc and a-vO₂ also showed a leftward shift of values in this group, indicative of a deficit in peripheral O₂ extraction even for submaximal exercise demands. Concurrent with lung hyperinflation, a distinctive blunting of exercise stroke volume expansion was also observed in this group. Conclusion: Contrary to the traditional view that cardiovascular complications were the hallmark of advanced disease, this study of early COPD spectrum showed a reduced exercise O₂ delivery and utilisation in individuals meeting spirometry criteria for stage II COPD. These findings reinforce the preventive clinical management approach to preserve peripheral muscle circulatory and oxidative capacities.

As ¾ of the global population either have excess or insufficient fat, it has become increasingly critical to understand the functions and dysfunctions of adipose tissue (AT). AT serves as a key organ in energy metabolism, and recently, attention has been focused on white AT, particularly its mitochondria, as the literature evidence links their functions to adiposity. This narrative review provides an overview of mitochondrial functionality in human white AT. Firstly, it is noteworthy that the two primary AT depots, subcutaneous AT (scAT) and visceral AT (vAT), exhibit differences in mitochondrial density and activity. Notably, vAT tends to have a higher mitochondrial activity compared to scAT. Subsequently, studies have unveiled a negative correlation between mitochondrial activity and body mass index (BMI), indicating that obesity is associated with a lower mitochondrial function. While the impact of exercise on AT mitochondria remains uncertain, dietary interventions have demonstrated varying effects on AT mitochondria. This variability holds promise for the modulation of AT mitochondrial activity. In summary, AT mitochondria exert a significant influence on health outcomes and can be influenced by factors such as obesity and dietary interventions. Understanding the mechanisms underlying these responses can offer potential insights into managing conditions related to AT and overall health.

Over the last decades, a growing interest in eccentric (ECC) exercise has emerged, but mitochondrial adaptations to ECC training remain poorly documented. Using an approach for manipulating mechanical and metabolic exercise power, we positioned that for same metabolic power, training using concentric (CON) or ECC contractions would induce similar skeletal muscle mitochondrial adaptations. Sixty adult rats were randomly assigned to a control (CTRL) or three treadmill training groups running at 15m·min⁻¹ for 45min, 5days weekly for 8 weeks at targeted upward or downward slopes. Animals from the CON (+15%) and ECC30 (-30%) groups trained at iso-metabolic power while CON and ECC15 (-15%) exercised at iso-mechanical power. Assessments were made of Vastus Intermedius mitochondrial respiration (oxygraphy), enzymatic activities (spectrophotometry) and real-time qPCR for mRNA transcripts. Maximal rates of mitochondrial respiration was 14-15% higher in CON and ECC30 compared to CTRL and ECC15. Apparent K_m for ADP for trained groups was 40-66% higher than CTRL, with statistical significance reached for CON and ECC30. Complex I and citrate synthase activities were 1.6 (ECC15) to 1.8 (ECC30 and CON) times values of CTRL. Complex IV activity was higher than CTRL (p<0.05) only for CON and ECC30. mRNA transcripts analyses showed higher TFAM, SLC25A4, CKMT2 and PPID in the ECC30 compared to CTRL. Findings confirm that training-induced skeletal muscle mitochondrial function adaptations are governed by the extent of metabolic overload irrespective of exercise modality. The distinctive ECC30 mRNA transcript pattern may reflect a cytoskeleton damage-repair or ECC adaptive cycle that differs from that of biogenesis.

Several brands of water enriched with O₂ (O₂-waters) are commercially available and are advertised as wellness and fitness waters with claims of physiological and psychological benefits, including improvement in exercise performance. However, these claims are based, at best, on anecdotal evidence or on a limited number of unreliable studies. The purpose of this double-blind randomized study was to compare the effect of two O₂-waters (~110 mg O₂·L⁻¹) and a placebo (10 mg O₂·L⁻¹, i.e., close to the value at sea level, 9–12 mg O₂·L⁻¹) on the cardiopulmonary responses and on performance during high-intensity exercise. One of the two O₂-waters and the placebo were prepared by injection of O₂. The other O₂-water was enriched by an electrolytic process. Twenty male subjects were randomly allocated to drink one of the three waters in a crossover study (2 L·day⁻¹ × 2 days and 15 mL·kg⁻¹ 90 min before exercise). During each exercise trial, the subjects exercised at 95.9 ± 4.7% of maximal workload to volitional fatigue. Exercise time to exhaustion and the cardiopulmonary responses, arterial lactate concentration and pH were measured. Oxidative damage to proteins, lipids and DNA in blood was assessed at rest before exercise. Time to exhaustion (one-way ANOVA) and the responses to exercise (two-way ANOVA [Time; Waters] with repeated measurements) were not significantly different among the three waters. There was only a trend (p = 0.060) for a reduction in the time constant of the rapid component of VO₂ kinetics with the water enriched in O₂ by electrolysis. No difference in oxidative damage in blood was observed between the three waters. These results suggest that O₂-water does not speed up cardiopulmonary response to exercise, does not increase performance and does not trigger oxidative stress measured at rest.