Respiratory viral coinfections in pediatric patients in the primary care setting: a multicenter prospective study within the COPEDICAT network.

Acute respiratory viral infections pose a significant healthcare burden on the pediatric population globally, but data on the dissemination pattern in the community due to the COVID-19 pandemic are scarce. We conducted a two-year prospective multicenter study in Catalonia (Spain) that examined the prevalence and coinfection dynamics of respiratory viruses among 1276 pediatric patients from different age groups attending primary care. Coinfection analysis demonstrated complex patterns and revealed a coinfection rate of 23.8% for SARS-CoV-2, often in association with rhinovirus or influenza A. This study provides valuable data to understand post-pandemic viral interactions, which is imperative for public health interventions.

Recognising the importance and impact of Imaging Scientists: Global guidelines for establishing career paths within core facilities.

In the dynamic landscape of scientific research, imaging core facilities are vital hubs propelling collaboration and innovation at the technology development and dissemination frontier. Here, we present a collaborative effort led by Global BioImaging (GBI), introducing international recommendations geared towards elevating the careers of Imaging Scientists in core facilities. Despite the critical role of Imaging Scientists in modern research ecosystems, challenges persist in recognising their value, aligning performance metrics and providing avenues for career progression and job security. The challenges encompass a mismatch between classic academic career paths and service-oriented roles, resulting in a lack of understanding regarding the value and impact of Imaging Scientists and core facilities and how to evaluate them properly. They further include challenges around sustainability, dedicated training opportunities and the recruitment and retention of talent. Structured across these interrelated sections, the recommendations within this publication aim to propose globally applicable solutions to navigate these challenges. These recommendations apply equally to colleagues working in other core facilities and research institutions through which access to technologies is facilitated and supported. This publication emphasises the pivotal role of Imaging Scientists in advancing research programs and presents a blueprint for fostering their career progression within institutions all around the world.

Parents' perspectives on SARS-CoV-2 vaccinations for children: a qualitative analysis.

BACKGROUND: Uptake of the SARS-CoV-2 vaccine for children aged 5-11 years has been lower than anticipated in Canada. Although research has explored parental intentions toward SARS-CoV-2 vaccination for children, parental decisions regarding vaccinations have not been studied in-depth. We sought to explore reasons why parents chose to vaccinate or not vaccinate their children against SARS-CoV-2 to better understand their decisions. METHODS: We conducted a qualitative study involving in-depth individual interviews with a purposive sample of parents in the Greater Toronto Area, Ontario, Canada. We conducted interviews via telephone or video call from February to April 2022 and analyzed the data using reflexive thematic analysis. RESULTS: We interviewed 20 parents. We found that parental attitudes toward SARS-CoV-2 vaccinations for their children represented a complex continuum of concern. We identified 4 cross-cutting themes: the newness of SARS-CoV-2 vaccines and the evidence supporting their use; the perceived politicization of guidance for SARS-CoV-2 vaccination; the social pressure surrounding SARS-CoV-2 vaccinations; and the weighing of individual versus collective benefits of vaccination. Parents found making a decision about vaccinating their child challenging and expressed difficulty sourcing and evaluating evidence, determining the trustworthiness of guidance, and balancing their own conceptions of health care decisions with societal expectations and political messaging. INTERPRETATION: Parents' experiences making decisions regarding SARS-CoV-2 vaccination for their children were complex, even for those who were supportive of SARS-CoV-2 vaccinations. These findings provide some explanation for the current patterns of uptake of SARS-CoV-2 vaccination among children in Canada; health care providers and public health authorities can consider these insights when planning future vaccine rollouts.

Improving social justice in observational studies: protocol for the development of a global and Indigenous STROBE-equity reporting guideline.

BACKGROUND: Addressing persistent and pervasive health inequities is a global moral imperative, which has been highlighted and magnified by the societal and health impacts of the COVID-19 pandemic. Observational studies can aid our understanding of the impact of health and structural oppression based on the intersection of gender, race, ethnicity, age and other factors, as they frequently collect this data. However, the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guideline, does not provide guidance related to reporting of health equity. The goal of this project is to develop a STROBE-Equity reporting guideline extension. METHODS: We assembled a diverse team across multiple domains, including gender, age, ethnicity, Indigenous background, disciplines, geographies, lived experience of health inequity and decision-making organizations. Using an inclusive, integrated knowledge translation approach, we will implement a five-phase plan which will include: (1) assessing the reporting of health equity in published observational studies, (2) seeking wide international feedback on items to improve reporting of health equity, (3) establishing consensus amongst knowledge users and researchers, (4) evaluating in partnership with Indigenous contributors the relevance to Indigenous peoples who have globally experienced the oppressive legacy of colonization, and (5) widely disseminating and seeking endorsement from relevant knowledge users. We will seek input from external collaborators using social media, mailing lists and other communication channels. DISCUSSION: Achieving global imperatives such as the Sustainable Development Goals (e.g., SDG 10 Reduced inequalities, SDG 3 Good health and wellbeing) requires advancing health equity in research. The implementation of the STROBE-Equity guidelines will enable a better awareness and understanding of health inequities through better reporting. We will broadly disseminate the reporting guideline with tools to enable adoption and use by journal editors, authors, and funding agencies, using diverse strategies tailored to specific audiences.

SARS-CoV-2 transmission in teenagers and young adults in Fútbol Club Barcelona's Multidisciplinary Sports Training Academy.

Most studies, aimed at determining the incidence and transmission of SARS-CoV-2 in children and teenagers, have been developed in school settings. Our study conducted surveillance and inferred attack rates focusing on the practice of sports. Prospective and observational study of those attending the sports facilities of Fútbol Club Barcelona (FCB), in Barcelona, Spain, throughout the 2020-2021 season. Participants were young players (from five different sports) and adult workers, who belonged to stable teams (shared routines and were involved in same quarantine rules). Biweekly health questionnaires and SARS-CoV-2 screening were conducted. From the 234 participants included, 70 (30%) both lived and trained in the FCB facilities (Recruitment Pathway 1;RP1) and 164 (70%) lived at their own household and just came to the facilities to train (RP2). During the study, 38 positive cases were identified; none had severe symptoms or needed hospitalization. The overall weekly incidence in the cohorts did not differ compared to the one expected in the community, except for 2 weeks when an outbreak occurred. The attack rate (AR) was three times higher for the participants from RP1, in comparison to those from RP2 (p < 0.01). A Basketball team showed a significant higher AR.  Conclusion: Physical activities in stable teams are not related to an increased risk of transmission of SARS-CoV-2, since there were the same observed cases than expected in the community. The risk is higher in indoor sports (Basketball vs. Football), and in closed cohort living settings (RP1 vs. RP2). The fulfilment of preventive measures is essential. What is Known: • Despite the low numerical impact caused in paediatric hospitalizations during COVID-19 pandemic, the social impact has been maximum. • The transmission potential in children and teenagers is limited, and it had been widely demonstrated in school settings. What is New: • Group physical activities in children and teenagers are not also related to an increased risk of transmission of SARS-CoV-2, when preventive measures, such as washing hands, and screening protocols are applied. • Routine and semi-professional sports activities seem safe environments to promote during this pandemic.

Multisystem inflammatory syndrome in children and SARS-CoV-2 variants: a two-year ambispective multicentric cohort study in Catalonia, Spain.

Multisystem inflammatory syndrome in children (MIS-C) is a rare but severe disease temporarily related to SARS-CoV-2. We aimed to describe the epidemiological, clinical, and laboratory findings of all MIS-C cases diagnosed in children < 18 years old in Catalonia (Spain) to study their trend throughout the pandemic. This was a multicenter ambispective observational cohort study (April 2020-April 2022). Data were obtained from the COVID-19 Catalan surveillance system and from all hospitals in Catalonia. We analyzed MIS-C cases regarding SARS-CoV-2 variants for demographics, symptoms, severity, monthly MIS-C incidence, ratio between MIS-C and accumulated COVID-19 cases, and associated rate ratios (RR). Among 555,848 SARS-CoV-2 infections, 152 children were diagnosed with MIS-C. The monthly MIS-C incidence was 4.1 (95% CI: 3.4-4.8) per 1,000,000 people, and 273 (95% CI: 230-316) per 1,000,000 SARS-CoV-2 infections (i.e., one case per 3,700 SARS-CoV-2 infections). During the Omicron period, the MIS-C RR was 8.2 (95% CI: 5.7-11.7) per 1,000,000 SARS-CoV-2 infections, which was significantly lower (p < 0.001) than that for previous variant periods in all age groups. The median [IQR] age of MIS-C was 8 [4-11] years, 62.5% male, and 80.2% without comorbidities. Common symptoms were gastrointestinal findings (88.2%) and fever > 39 °C (81.6%); nearly 40% had an abnormal echocardiography, and 7% had coronary aneurysm. Clinical manifestations and laboratory data were not different throughout the variant periods (p > 0.05).  Conclusion: The RR between MIS-C cases and SARS-CoV-2 infections was significantly lower in the Omicron period for all age groups, including those not vaccinated, suggesting that the variant could be the main factor for this shift in the MISC trend. Regardless of variant type, the patients had similar phenotypes and severity throughout the pandemic. What is Known: • Before our study, only two publications investigated the incidence of MIS-C regarding SARS-CoV-2 variants in Europe, one from Southeast England and another from Denmark. What is New: • To our knowledge, this is the first study investigating MIS-C incidence in Southern Europe, with the ability to recruit all MIS-C cases in a determined area and analyze the rate ratio for MIS-C among SARS-CoV-2 infections throughout variant periods. • We found a lower rate ratio of MISC/infections with SARS-CoV-2 in the Omicron period for all age groups, including those not eligible for vaccination, suggesting that the variant could be the main factor for this shift in the MISC trend.

Parent and physician beliefs, perceptions and knowledge of plant milks for children.

Background: Parent and physician perceptions of plant milk are unclear. Aim: To explore parent and physician perceptions of plant milk for children and to gain a better understanding of why parents and physicians might choose plant milk for children. Methods: A mixed methods study was conducted using a questionnaire and interviews with parents and physicians participating in the TARGet Kids! cohort study. Questionnaire data were analyzed using descriptive statistics. Interview transcripts were analyzed using thematic analysis. Results: Parents reported a variety of reasons for choosing plant milk for their children including concerns around allergies, the environment, animal welfare, plant-based diet, health benefits, taste and hormones in cow's milk. Parents gave their children various types of plant milks and physicians provided various recommendations to parents of children not consuming cow's milk. Our study identified that 79% of parents and 51% of physicians were unaware that soy milk is the recommended cow's milk substitute for children. Additionally, 26% of parents did not know some plant milks are not fortified and can contain added sugar. Three main themes were identified from interviews about why parents and physicians may choose plant milk for children: (i) healthiness of plant milk; (ii) concerns about hormones; and (iii) environmental impacts. Conclusions: Parents and physicians choose the milk that they believe is healthiest for their child or patient. However, a lack of clarity on the effects of plant milk consumption on children's health resulted in conflicting views on whether plant milk or cow's milk is healthier for children.

Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 Infection Among Children in Summer Schools Applying Stringent Control Measures in Barcelona, Spain.

BACKGROUND: Understanding the role of children in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission is critical to guide decision-making for schools in the pandemic. We aimed to describe the transmission of SARS-CoV-2 among children and adult staff in summer schools. METHODS: During July 2020, we prospectively recruited children and adult staff attending summer schools in Barcelona who had SARS-CoV-2 infection. Primary SARS-CoV-2 infections were identified through (1) a surveillance program in 22 summer schools of 1905 participants, involving weekly saliva sampling for SARS-CoV-2 reverse-transcription polymerase chain reaction (RT-PCR) during 2-5 weeks; and (2) cases identified through the Catalonian Health Surveillance System of children diagnosed with SARS-CoV-2 infection by nasopharyngeal RT-PCR. All centers followed prevention protocols: bubble groups, handwashing, face masks, and conducting activities mostly outdoors. Contacts of a primary case within the same bubble were evaluated by nasopharyngeal RT-PCR. Secondary attack rates and the effective reproduction number in summer schools (Re*) were calculated. RESULTS: Among the >2000 repeatedly screened participants, 30 children and 9 adults were identified as primary cases. A total of 253 close contacts of these primary cases were studied (median, 9 [interquartile range, 5-10] for each primary case), among which 12 new cases (4.7%) were positive for SARS-CoV-2. The Re* was 0.3, whereas the contemporary rate in the general population from the same areas in Barcelona was 1.9. CONCLUSIONS: The transmission rate of SARS-CoV-2 infection among children attending school-like facilities under strict prevention measures was lower than that reported for the general population. This suggests that under preventive measures schools are unlikely amplifiers of SARS-CoV-2 transmission, supporting current recommendations for school opening.

Is equity considered in systematic reviews of interventions for mitigating social isolation and loneliness in older adults?

BACKGROUND: Social isolation and loneliness affect one in four older adults in many regions around the world. Social isolation and loneliness are shown to be associated with declines in physical and mental health. Intersecting social determinants of health influence both the risk of being socially isolated and lonely as well as the access and uptake of interventions. Our objective is to evaluate what evidence is available within systematic reviews on how to mitigate inequities in access to and effectiveness of interventions. METHODS: We performed an overview of reviews following methods of the Cochrane Handbook for Overviews of Reviews. We selected systematic reviews of effectiveness of interventions aimed at mitigating social isolation and loneliness in older adults (aged 60 or above) published in the last 10 years. In addition, we assessed all primary studies from the most recent systematic review with a broad intervention focus. We searched MEDLINE, EMBASE, PsycINFO, CINAHL, and Scopus in collaboration with a librarian scientist. We used a structured framework called PROGRESS-Plus to assess the reporting and consideration of equity. PROGRESS-Plus stands for place of residence, race/ethnicity/culture/language, occupation, gender or sex, religion, education, socioeconomic status (SES), social capital, while "plus" stands for additional factors associated with discrimination and exclusion such as age, disability, and sexual orientation. We assessed whether PROGRESS-Plus factors were reported in description of the population, examination of differential effects, or discussion of applicability or limitations. RESULTS: We identified and assessed 17 eligible systematic reviews. We assessed all 23 primary studies from the most recent systematic review with a broad intervention focus. All systematic reviews and primary studies described the population by one or more PROGRESS-Plus factor, most commonly across place of residence and age, respectively. None of the reviews and five primary studies examined differential effects across one or more PROGRESS-Plus dimension. Nine reviews and four primary studies discussed applicability or limitations of their findings by at least one PROGRESS-Plus factor. CONCLUSIONS: Although we know that social isolation and loneliness are worse for the poorest and most socially disadvantaged older adults, the existing evidence base lacks details on how to tailor interventions for these socially disadvantaged older people.

Empirical model for short-time prediction of COVID-19 spreading.

The appearance and fast spreading of Covid-19 took the international community by surprise. Collaboration between researchers, public health workers, and politicians has been established to deal with the epidemic. One important contribution from researchers in epidemiology is the analysis of trends so that both the current state and short-term future trends can be carefully evaluated. Gompertz model has been shown to correctly describe the dynamics of cumulative confirmed cases, since it is characterized by a decrease in growth rate showing the effect of control measures. Thus, it provides a way to systematically quantify the Covid-19 spreading velocity and it allows short-term predictions and longer-term estimations. This model has been employed to fit the cumulative cases of Covid-19 from several European countries. Results show that there are systematic differences in spreading velocity among countries. The model predictions provide a reliable picture of the short-term evolution in countries that are in the initial stages of the Covid-19 outbreak, and may permit researchers to uncover some characteristics of the long-term evolution. These predictions can also be generalized to calculate short-term hospital and intensive care units (ICU) requirements.

Modelling the dynamics of tuberculosis lesions in a virtual lung: Role of the bronchial tree in endogenous reinfection.

Tuberculosis (TB) is an infectious disease that still causes more than 1.5 million deaths annually. The World Health Organization estimates that around 30% of the world's population is latently infected. However, the mechanisms responsible for 10% of this reserve (i.e., of the latently infected population) developing an active disease are not fully understood, yet. The dynamic hypothesis suggests that endogenous reinfection has an important role in maintaining latent infection. In order to examine this hypothesis for falsifiability, an agent-based model of growth, merging, and proliferation of TB lesions was implemented in a computational bronchial tree, built with an iterative algorithm for the generation of bronchial bifurcations and tubes applied inside a virtual 3D pulmonary surface. The computational model was fed and parameterized with computed tomography (CT) experimental data from 5 latently infected minipigs. First, we used CT images to reconstruct the virtual pulmonary surfaces where bronchial trees are built. Then, CT data about TB lesion' size and location to each minipig were used in the parameterization process. The model's outcome provides spatial and size distributions of TB lesions that successfully reproduced experimental data, thus reinforcing the role of the bronchial tree as the spatial structure triggering endogenous reinfection. A sensitivity analysis of the model shows that the final number of lesions is strongly related with the endogenous reinfection frequency and maximum growth rate of the lesions, while their mean diameter mainly depends on the spatial spreading of new lesions and the maximum radius. Finally, the model was used as an in silico experimental platform to explore the transition from latent infection to active disease, identifying two main triggering factors: a high inflammatory response and the combination of a moderate inflammatory response with a small breathing amplitude.

DRAVET ENGAGE. Parent caregivers of children with Dravet syndrome: Perspectives, needs, and opportunities for clinical research.

Dravet syndrome (DS) is an intractable developmental and epileptic encephalopathy significantly impacting affected children and their families. A novel, one-time, adeno-associated virus (AAV)-mediated gene regulation therapy was designed to treat the underlying cause of DS, potentially improving the full spectrum of DS manifestations. To ensure the first-in-human clinical trial addresses meaningful outcomes for patients and families, we examined their perspectives, priorities, goals, and desired outcomes in the design phase through a mixed methods approach (quantitative and qualitative). We conducted a non-identifiable parent caregiver survey, shared through a patient advocacy organization (n = 36 parents; children age ≤6 years). Parents were also engaged via three group discussions (n = 10; children age 2-20 years) and optional follow-up in-depth individual interviews (n = 6). Qualitative data analysis followed an inductive interpretive process, and qualitative researchers conducted a thematic analysis with a narrative approach. Survey results revealed most children (94%) were diagnosed by age 1, with onset of seizures at mean age 6.2 months and other DS manifestations before 2 years. The most desired disease aspects to address with potential new disease-modifying therapies were severe seizures (ranked by 92% of caregivers) and communication issues (development, expressive, receptive; 72-83%). Qualitative results showed the need for trial outcomes that recognize the impact of DS on the whole family. Parents eventually hope for trials including children of all ages and were both excited about the potential positive impact of a one-time disease-modifying therapy and mindful of potential long-term implications. Participants reflected on the details and risks of a clinical trial design (e.g., sham procedures) and described the different factors that relate to their decision to participate in a trial. Their main aspirations were to stop neurodevelopmental stagnation, to reduce seizures, and to reduce the impact on their families' wellbeing. To our knowledge, this is the first study within a patient-oriented research framework that specifically explored parents' needs and perceptions regarding clinical trials of a potential disease-modifying therapy for children with a severe, developmental disease, such as DS.

Nicotinamide riboside does not alter mitochondrial respiration, content or morphology in skeletal muscle from obese and insulin-resistant men.

KEY POINTS: This is the first long-term human clinical trial to report on effects of nicotinamide riboside (NR) on skeletal muscle mitochondrial function, content and morphology. NR supplementation decreases nicotinamide phosphoribosyltransferase (NAMPT) protein abundance in skeletal muscle. NR supplementation does not affect NAD metabolite concentrations in skeletal muscle. Respiration, distribution and quantity of muscle mitochondria are unaffected by NR. NAMPT in skeletal muscle correlates positively with oxidative phosphorylation Complex I, sirtuin 3 and succinate dehydrogenase. ABSTRACT: Preclinical evidence suggests that the nicotinamide adenine dinucleotide (NAD+ ) precursor nicotinamide riboside (NR) boosts NAD+ levels and improves diseases associated with mitochondrial dysfunction. We aimed to determine if dietary NR supplementation in middle-aged, obese, insulin-resistant men affects mitochondrial respiration, content and morphology in skeletal muscle. In a randomized, placebo-controlled clinical trial, 40 participants received 1000 mg NR or placebo twice daily for 12 weeks. Skeletal muscle biopsies were collected before and after the intervention. Mitochondrial respiratory capacity was determined by high-resolution respirometry on single muscle fibres. Protein abundance and mRNA expression were measured by Western blot and quantitative PCR analyses, respectively, and in a subset of the participants (placebo n = 8; NR n = 8) we quantified mitochondrial fractional area and mitochondrial morphology by laser scanning confocal microscopy. Protein levels of nicotinamide phosphoribosyltransferase (NAMPT), an essential NAD+ biosynthetic enzyme in skeletal muscle, decreased by 14% with NR. However, steady-state NAD+ levels as well as gene expression and protein abundance of other NAD+ biosynthetic enzymes remained unchanged. Neither respiratory capacity of skeletal muscle mitochondria nor abundance of mitochondrial associated proteins were affected by NR. Moreover, no changes in mitochondrial fractional area or network morphology were observed. Our data do not support the hypothesis that dietary NR supplementation has significant impact on skeletal muscle mitochondria in obese and insulin-resistant men. Future studies on the effects of NR on human skeletal muscle may include both sexes and potentially provide comparisons between young and older people.

The dynamic life of the glycogen granule.

Glycogen, the primary storage form of glucose, is a rapid and accessible form of energy that can be supplied to tissues on demand. Each glycogen granule, or "glycosome," is considered an independent metabolic unit composed of a highly branched polysaccharide and various proteins involved in its metabolism. In this Minireview, we review the literature to follow the dynamic life of a glycogen granule in a multicompartmentalized system, i.e. the cell, and how and where glycogen granules appear and the factors governing its degradation. A better understanding of the importance of cellular compartmentalization as a regulator of glycogen metabolism is needed to unravel its role in brain energetics.

PGC-1α regulates mitochondrial properties beyond biogenesis with aging and exercise training.

Impaired mitochondrial function has been implicated in the pathogenesis of age-associated metabolic diseases through regulation of cellular redox balance. Exercise training is known to promote mitochondrial biogenesis in part through induction of the transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α). Recently, mitochondrial ADP sensitivity has been linked to reactive oxygen species (ROS) emission with potential impact on age-associated physiological outcomes, but the underlying molecular mechanisms remain unclear. Therefore, the present study investigated the effects of aging and exercise training on mitochondrial properties beyond biogenesis, including respiratory capacity, ADP sensitivity, ROS emission, and mitochondrial network structure, in myofibers from inducible muscle-specific PGC-1α-knockout mice and control mice. Aged mice displayed lower running endurance and mitochondrial respiratory capacity than young mice. This was associated with intermyofibrillar mitochondrial network fragmentation, diminished submaximal ADP-stimulated respiration, increased mitochondrial ROS emission, and oxidative stress. Exercise training reversed the decline in maximal respiratory capacity independent of PGC-1α, whereas exercise training rescued the age-related mitochondrial network fragmentation and the impaired submaximal ADP-stimulated respiration in a PGC-1α-dependent manner. Furthermore, lack of PGC-1α was associated with altered phosphorylation and carbonylation of the inner mitochondrial membrane ADP/ATP exchanger adenine nucleotide translocase 1. In conclusion, the present study provides evidence that PGC-1α regulates submaximal ADP-stimulated respiration, ROS emission, and mitochondrial network structure in mouse skeletal muscle during aging and exercise training.

A qualitative study to understand parent and physician perspectives about cow's milk fat for children.

OBJECTIVE: Consensus guidelines recommend that children consume reduced-fat (0·1-2 %) cow's milk at age 2 years to reduce the risk of obesity. Behaviours and perspectives of parents and physicians about cow's milk fat for children are unknown. Objectives were to: (i) understand what cow's milk fat recommendations physicians provide to 2-year-old children; (ii) assess the acceptability of reduced-fat v. whole cow's milk in children's diets by parents and physicians; and (iii) explore attitudes and perceptions about cow's milk fat for children. DESIGN: Online questionnaires and individual interviews were conducted. Questionnaire data were analysed using descriptive statistics. Interview transcripts were analysed using a general inductive approach and thematic analysis. SETTING: The TARGet Kids! practice-based research network in Toronto, Canada. PARTICIPANTS: Questionnaire respondents included fifty parents and fifteen physicians; individual interviews were conducted with with fourteen parents and twelve physicians. RESULTS: Physicians provided various milk fat recommendations for 2-year-old children. Parents also provided different cow's milks: eighteen (36 %) provided whole milk and twenty-nine (58 %) provided reduced-fat milk. Analysis of qualitative interviews revealed three themes: (i) healthy eating behaviours, (ii) trustworthy nutrition information and (iii) importance of dietary fat for children. CONCLUSIONS: Parents provide, and physicians recommend, a variety of cow's milks for children and hold mixed interpretations of the role of cow's milk fat in children's diets. Clarity about its effect on child adiposity is needed to help make informed decisions about cow's milk fat for children.

Perturbations of NAD+ salvage systems impact mitochondrial function and energy homeostasis in mouse myoblasts and intact skeletal muscle.

Nicotinamide adenine dinucleotide (NAD+) can be synthesized by nicotinamide phosphoribosyltransferase (NAMPT). We aimed to determine the role of NAMPT in maintaining NAD+ levels, mitochondrial function, and metabolic homeostasis in skeletal muscle cells. We generated stable Nampt knockdown (sh Nampt KD) C2C12 cells using a shRNA lentiviral approach. Moreover, we applied gene electrotransfer to express Cre recombinase in tibialis anterior muscle of floxed Nampt mice. In sh Nampt KD C2C12 myoblasts, Nampt and NAD+ levels were reduced by 70% and 50%, respectively, and maximal respiratory capacity was reduced by 25%. Moreover, anaerobic glycolytic flux increased by 55%, and 2-deoxyglucose uptake increased by 25% in sh Nampt KD cells. Treatment with the NAD+ precursor nicotinamide riboside restored NAD+ levels in sh Nampt cells and increased maximal respiratory capacity by 18% and 32% in control and sh Nampt KD cells, respectively. Expression of Cre recombinase in muscle of floxed Nampt mice reduced NAMPT and NAD+ levels by 38% and 43%, respectively. Glucose uptake increased by 40%, and mitochondrial complex IV respiration was compromised by 20%. Hypoxia-inducible factor (HIF)-1α-regulated genes and histone H3 lysine 9 (H3K9) acetylation, a known sirtuin 6 (SIRT6) target, were increased in shNampt KD cells. Thus, we propose that the shift toward glycolytic metabolism observed, at least in part, is mediated by the SIRT6/HIF1α axis. Our findings suggest that NAMPT plays a key role for maintaining NAD+ levels in skeletal muscle and that NAMPT deficiency compromises oxidative phosphorylation capacity and alters energy homeostasis in this tissue.

Hepatic mitochondrial oxidative phosphorylation is normal in obese patients with and without type 2 diabetes.

KEY POINTS: Hepatic insulin resistance in patients with obesity or type 2 diabetes has been suggested to result from hepatic mitochondrial dysfunction. High-resolution respirometry (HRR) can be used to assess oxidative phosphorylation by measuring the mitochondrial oxygen consumption rate in the individual complexes of the mitochondria. By using HRR, the present study demonstrates no difference in hepatic mitochondrial oxidative phosphorylation among subjects with obesity with or without type 2 diabetes and non-obese controls. Furthermore, the amount of mitochondria, assessed by the citrate synthase activity, is not different between the three groups. Together the present findings indicate that hepatic mitochondrial oxidative phosphorylation capacity is not impaired in patients with obesity or type 2 diabetes. ABSTRACT: Obese patients with type 2 diabetes (T2DM) and without type 2 diabetes (OB) are characterized by high hepatic lipid content and hepatic insulin resistance. This may be linked to impaired hepatic mitochondrial oxidative phosphorylation (OXPHOS) capacity. The aim of the present study was to investigate and compare hepatic mitochondrial OXPHOS capacity in T2DM, OB and non-obese controls (CON). Seventeen obese patients (nine OB and eight T2DM) and six CON patients had perioperative liver biopsies taken. Samples were divided into three parts to measure (1) complex I, II and IV linked respiration, (2) citrate synthase (CS) activity and (3) lipid droplet (LD) size and area (% of total tissue area filled by LDs). State 3 respiration of complex I, II and IV and the CS activity did not differ in OB, T2DM and CON. LD size was significantly higher in T2DM compared with CON, and LD area tended (P = 0.10) to be higher in T2DM and OB compared with CON. The present findings indicate that hepatic OXPHOS capacity is not different in patients with markedly different weight and glycaemic control. Furthermore, the results do not support impaired hepatic mitochondrial respiratory capacity playing a major role in the development of obesity-induced type 2 diabetes.

Effects of immobilization and aerobic training on proteins related to intramuscular substrate storage and metabolism in young and older men.

PURPOSE: Aging and inactivity lead to skeletal muscle metabolic inflexibility, but the underlying molecular mechanisms are not entirely elucidated. Therefore, we investigated how muscle lipid and glycogen stores and major regulatory proteins were affected by short-term immobilization followed by aerobic training in young and older men. METHODS: 17 young (23 ± 1 years, 24 ± 1 kg m(-2), and 20 ± 2% body fat) and 15 older men (68 ± 1 years; 27 ± 1 kg m(-2), and 29 ± 2% body fat) underwent 2 weeks' one leg immobilization followed by 6 weeks' cycle training. Biopsies were obtained from m. vastus lateralis just before immobilization (at inclusion), after immobilization, and the after 6 weeks' training. The biopsies were analyzed for muscle substrates; muscle perilipin protein (PLIN), glycogen synthase (GS), synaptosomal-associated protein of 23 kDa (SNAP23) protein content, and muscle 3-hydroxyacyl-CoA dehydrogenase (HAD) activity RESULTS: The older men had higher intramuscular triglyceride (IMTG) (73 %) and Glycogen (16%) levels compared to the young men, and IMTG tended to increase with immobilization. PLIN2 and 3 protein content increased with immobilization in the older men only. The young men had higher GS (74%) protein compared to the older men. Immobilization decreased and training restored HAD activity, GS and SNAP23 protein content in young and older men. CONCLUSION: Evidence of age-related metabolic inflexibility is presented, seen as body fat and IMTG accumulation. The question arises as to whether IMTG accumulation in the older men is caused by or leading to the increase in PLIN2 and 3 protein content. Training decreased body fat and IMTG levels in both young and older men; hence, training should be prioritized to reduce the detrimental effect of aging on metabolism.