Lysosomes drive the piecemeal removal of mitochondrial inner membrane.

Mitochondrial membranes define distinct structural and functional compartments. Cristae of the inner mitochondrial membrane (IMM) function as independent bioenergetic units that undergo rapid and transient remodelling, but the significance of this compartmentalized organization is unknown1. Using super-resolution microscopy, here we show that cytosolic IMM vesicles, devoid of outer mitochondrial membrane or mitochondrial matrix, are formed during resting state. These vesicles derived from the IMM (VDIMs) are formed by IMM herniation through pores formed by voltage-dependent anion channel 1 in the outer mitochondrial membrane. Live-cell imaging showed that lysosomes in proximity to mitochondria engulfed the herniating IMM and, aided by the endosomal sorting complex required for transport machinery, led to the formation of VDIMs in a microautophagy-like process, sparing the remainder of the organelle. VDIM formation was enhanced in mitochondria undergoing oxidative stress, suggesting their potential role in maintenance of mitochondrial function. Furthermore, the formation of VDIMs required calcium release by the reactive oxygen species-activated, lysosomal calcium channel, transient receptor potential mucolipin 1, showing an interorganelle communication pathway for maintenance of mitochondrial homeostasis. Thus, IMM compartmentalization could allow for the selective removal of damaged IMM sections via VDIMs, which should protect mitochondria from localized injury. Our findings show a new pathway of intramitochondrial quality control.

Updated joint ESPGHAN/NASPGHAN guidelines for management of Helicobacter pylori infection in children and adolescents (2023).

BACKGROUND: Evolving epidemiological data and increasing antibiotic resistance mandate an update of the European and North American Societies of Pediatric Gastroenterology, Hepatology and Nutrition guidelines. METHODS: Certainty of evidence and strength of recommendations were rated by experts according to the Grading of Recommendation Assessment, Development, and Evaluation approach. PICO (patient population, intervention, comparator, and outcome) questions were developed and voted on by the group. Recommendations were formulated using the Evidence to Decision framework. RESULTS: The current literature supports many of the previous recommendations and several new recommendations. Invasive testing with strain antimicrobial susceptibility analysis is recommended for the diagnosis and selection of eradication therapy for H. pylori infection. Molecular methods are acceptable for detection of infection and of antibiotic resistance in gastric biopsy specimens. Reliable, noninvasive tests can be used as a screening method for children with history of gastric cancer in a first-degree relative. When investigating causes of chronic immune thrombocytopenic purpura, testing for H. pylori is no longer recommended. When investigating other diseases such as inflammatory bowel disease, celiac disease, or eosinophilic esophagitis, specific diagnostic biopsies for H. pylori infection are not indicated. However, if H. pylori is an incidental finding, treatment may be considered after discussing the risks and benefits. Treatment should be based on antibiotic antimicrobial susceptibility testing and, if unavailable, regimens containing clarithromycin should be avoided. CONCLUSIONS: Due to decreasing prevalence of infection, increasing challenges with antibiotic resistance, and emerging evidence regarding complications of infection, clinicians must be aware of these recommended changes to appropriately manage H. pylori infection and its clinical sequelae in children.

Training Outcomes and Satisfaction in Canadian MD/PhD and MD/MSc Programs: Findings from a National Survey.

PURPOSE: Despite the impact of physician-scientists on scientific discovery and translational medicine, several reports have signalled their declining workforce, reduced funding, and insufficient protected research time. Given the paucity of outcome data on Canadian MD/PhD programs, this study presents a national portrait of the sociodemographic characteristics, training trajectories, productivity, and satisfaction in trainees and alumni from Canadian MD/PhD and MD/MSc programs. METHODS: Quantitative data were collected in a national survey launched in 2021. Respondents included 74 MD/PhD alumni and 121 trainees across 12 Canadian MD/PhD and MD/MSc programs. RESULTS: Among MD/PhD alumni, 51% were independent practitioners/researchers while others underwent residency training. Most trainees (88%) were in MD/PhD programs. Significantly more alumni identified as men than did trainees. Significantly more alumni conducted clinical and health services research, while more trainees conducted basic science research. Average time to MD/PhD completion was 8 years, with no correlation to subsequent research outcomes. Self-reported research productivity was highest during MD/PhD training. Concerning training trajectories, most alumni completed residency, pursued additional training, and practised in Canada. Finally, regression models showed that trainees and alumni were satisfied with programs, with significant moderators in trainee models. CONCLUSION: Survey findings showed Canadian MD/PhD and MD/MSc programs recruit more diverse cohorts of trainees than before, provide productive research years, and graduate alumni who pursue training and academic employment in Canada. Both alumni and trainees are largely satisfied with these training programs. The need to collect in-depth longitudinal data on Canadian MD/PhD graduates to monitor diversity and success metrics is discussed.

Understanding associations between the COVID-19 pandemic and menstrual hygiene management among adolescent girls in Ethiopia: findings from a mixed-methods longitudinal study.

OBJECTIVE: To understand the relationship between the COVID-19 pandemic and menstrual hygiene management (MHM) among adolescent girls in Ethiopia and to explore which girls were most affected by pandemic disruptions. DESIGN: Two rounds of data from surveys and interviews were collected with adolescent girls immediately prior to and during the COVID-19 pandemic. The primary analysis is cross-sectional, controlling for pre-COVID-19 covariates. SETTING: The setting was three zones in two regions of Ethiopia: East Hararghe and East Shewa Zones in Oromia and South Gondar Zone in Amhara. Data were collected in December 2019-March 2020 and September 2020-February 2021. PARTICIPANTS: 742 adolescent girls, ages 11-25 years. OUTCOME MEASURES: Four primary outcomes were explored (1) the number of challenges girls experienced; (2) adolescent-identified challenges managing menstrual hygiene; (3) adolescent-identified difficulties accessing MHM products and (4) adolescent-identified difficulties accessing soap or water. RESULTS: Girls who were more vulnerable to COVID-19 were more likely to have worse MHM outcomes. An SD increase in household vulnerability to COVID-19 was associated with an 8.7 percentage point increase in the likelihood that the respondent had difficulty getting MHM products (p<0.001), a 6 percentage point increase in the likelihood that she reported facing a challenge managing her menstruation (p=0.003) and a 5.2 percentage point increase in the likelihood she lacked soap or water (p=0.001). Qualitative themes, used to triangulate the quantitative findings, suggest that mobility restrictions, shutdowns of the local market, disruptions in supply chains, poverty, stigma and fear about contracting COVID-19 affected girls' access to MHM supplies. CONCLUSIONS: The results of this study suggest that MHM was left behind in the COVID-19 response. New programming and policy interventions need to address financial hardship and disruptions to supplies to manage menstruation as well as tackle the inequitable gender norms that stigmatise menstruation during emergencies.

Polymeric nanoparticle-based mRNA vaccine is protective against influenza virus infection in ferrets.

New therapies and vaccines based on nucleic acids combined with an efficient nanoparticle delivery vehicle have a broad applicability for different disease indications. An alternative delivery technology for the successfully applied lipid nanoparticles in mRNA SARS-CoV-2 vaccines are nanoparticles composed of biodegradable poly(amido)amine-based polymers with mRNA payload. To show that these polymeric nanoparticles can efficiently deliver influenza hemagglutinin mRNA to target tissues and elicit protective immune responses, a relevant ferret influenza challenge model was used. In this model, our nanoparticle-based vaccine elicited strong humoral and cellular immune responses in the absence of local and systemic reactogenicity. Upon virus challenge, vaccinated animals exhibited reduced clinical signs and virus load relative to unvaccinated control animals. Based on these findings, further investigation of the polymeric nanoparticles in the context of prophylactic vaccination is warranted. Future studies will focus on optimizing the payload, the nanoparticle stability, the efficacy in the context of pre-existing immunity, and the applicability of the technology to prevent other infectious diseases.

"People will talk about her if she is not circumcised": Exploring the patterning, drivers and gender norms around female genital mutilation in Ethiopia's Somali region.

Over the past decade there has been a burgeoning literature on social norms and the need to understand their context-specific patterning and trends to promote change, including to address the harmful practice of female genital mutilation (FGM), which affects around 200 million girls and women globally. This article draws on mixed-methods data collected in 2022 and 2023 with 1,020 adolescents and their caregivers, as well as key informants, from Ethiopia's Somali region to explore the patterning, drivers, and decision-making around FGM. Findings indicate that almost all Somali girls can expect to undergo FGM before age 15, and that infibulation is near universal. Critically, however, we find that respondents' understanding of infibulation is rooted in traditional practice, and many girls are now "partially" infibulated-an invasive procedure that girls nonetheless see as an improvement over the past. These shifts reflect religious leaders' efforts to eliminate traditional infibulation--and the health risks it entails--by promoting "less invasive" types of FGM as a requirement of Islam. We also find evidence of emergent medicalization of the practice, as mothers-who are the primary decision-makers-seek to further reduce risks. Adult and adolescent respondents agree that FGM is a deeply embedded social norm, but distinguish between FGM as a perceived religious requirement, and infibulation as a cultural requirement. For girls and women, the importance of FGM is framed around social acceptance, whereas boys and men focus on FGM as a requirement for marriage as it allows families to control girls' sexuality. The article concludes by reflecting on the implications of our findings for programming in high-prevalence contexts. Key conclusions include that FGM interventions should not rely on empowering individuals as "champions of change" but rather prioritize engagement with whole communities, and should be open in the short term to incremental harm-reduction approaches.

Intersectionality, gender norms, and young adolescents in context: a review of longitudinal multicountry research programmes to shape future action.

Discriminatory gender norms can intersect and interact with other dimensions of discrimination-such as age, race, ethnicity, disability, education status, and sexual orientation-to shape individuals' experiences and impact their health and wellbeing. This interaction is referred to as intersectionality. Although the theory has been in circulation since the late 1980s, only recently has it gained traction in low-income and middle-income settings, and it has yet to fully penetrate global research on adolescence. The social and structural intersectional drivers of adolescent health and wellbeing, particularly during early adolescence (age 10-14 years), are poorly understood. The evidence base for designing effective interventions for this formative period of life is therefore relatively small. In this Review, we examine how gender intersects with other forms of disadvantage in the early stages of adolescence. Analysing data from hybrid observation-intervention longitudinal studies with young adolescents in 16 countries, our aim is to inform the health and wellbeing of girls and boys from a range of social contexts, including in conflict settings. Adolescents' perceptions about gender norms vary by context, depend on individual opinion, and are shaped by socioecological drivers of gender inequalities in health. Shifting those perceptions is therefore challenging. We argue for the importance of applying an intersectionality lens to improve health and wellbeing outcomes for young adolescents and conclude with five practical recommendations for programme design and research.

Female Genital Mutilation in Ethiopia's Afar Region: Patterning, Drivers, and Decision-Making.

PURPOSE: To explore the patterning, practices, and drivers of female genital mutilation (FGM) in Ethiopia's Afar region. METHODS: This article draws on mixed-methods research conducted in 2022 in 18 rural communities in three districts of Ethiopia's Afar region. Survey data were collected from 1,022 adolescents and their caregivers. Qualitative interviews were conducted with approximately 270 adults and adolescents. RESULTS: The survey found that FGM remains practically universal (97% of sampled adolescent girls), and infibulation remains the norm (87% of girls). Most adolescent girls and caregivers reported that FGM is required by religion and should continue. When queried about the main reason for FGM, however, most cited culture rather than religion. Female caregivers and adolescent girls were more likely to report that FGM has benefits than risks; the reverse was true for male caregivers. Qualitative evidence suggests that even girls who are not reported as infibulated generally, and that the social benefits of FGM--especially regarding controlling girls' sexuality and facilitating their marriageability--are perceived to outweigh health risks. Where there are shifts in type of FGM, it is largely due to efforts of religious leaders who preach against infibulation and for "milder" types--and the growing scope of fathers to input into mothers' FGM decision-making and advocate for less invasive types. DISCUSSION: Eliminating FGM requires focusing on contexts where the practice is most invasive and progress is not yet visible. Given complex intrahousehold and intragenerational dynamics, this will necessitate engaging whole communities with sustained multipronged approaches to shift social norms.

No evidence of difference in mortality with amoxicillin versus co-amoxiclav for hospital treatment of community-acquired pneumonia.

OBJECTIVES: Current guidelines recommend broad-spectrum antibiotics for high-severity community-acquired pneumonia (CAP), potentially contributing to antimicrobial resistance (AMR). We aim to compare outcomes in CAP patients treated with amoxicillin (narrow-spectrum) versus co-amoxiclav (broad-spectrum), to understand if narrow-spectrum antibiotics could be used more widely. METHODS: We analysed electronic health records from adults (≥16 y) admitted to hospital with a primary diagnosis of pneumonia between 01-January-2016 and 30-September-2023 in Oxfordshire, United Kingdom. Patients receiving baseline ([-12 h,+24 h] from admission) amoxicillin or co-amoxiclav were included. The association between 30-day all-cause mortality and baseline antibiotic was examined using propensity score (PS) matching and inverse probability treatment weighting (IPTW) to address confounding by baseline characteristics and disease severity. Subgroup analyses by disease severity and sensitivity analyses with missing covariates imputed were also conducted. RESULTS: Among 16,072 admissions with a primary diagnosis of pneumonia, 9685 received either baseline amoxicillin or co-amoxiclav. There was no evidence of a difference in 30-day mortality between patients receiving initial co-amoxiclav vs. amoxicillin (PS matching: marginal odds ratio 0.97 [0.76-1.27], p = 0.61; IPTW: 1.02 [0.78-1.33], p = 0.87). Results remained similar across stratified analyses of mild, moderate, and severe pneumonia. Results were also similar with missing data imputed. There was also no evidence of an association between 30-day mortality and use of additional macrolides or additional doxycycline. CONCLUSIONS: There was no evidence of co-amoxiclav being advantageous over amoxicillin for treatment of CAP in 30-day mortality at a population-level, regardless of disease severity. Wider use of narrow-spectrum empirical treatment of moderate/severe CAP should be considered to curb potential for AMR.

The release of host-derived antibodies bound to the variant surface glycoprotein (VSG) of Trypanosoma brucei cannot be explained by pH-dependent conformational changes of the VSG dimer.

Background: Trypanosoma brucei is a protozoan parasite that evades the mammalian host's adaptive immune response by antigenic variation of the highly immunogenic variant surface glycoprotein (VSG). VSGs form a dense surface coat that is constantly recycled through the endosomal system. Bound antibodies are separated in the endosome from the VSG and destroyed in the lysosome. For VSGs it has been hypothesized that pH-dependent structural changes of the VSG could occur in the more acidic environment of the endosome and hence, facilitate the separation of the antibody from the VSG. Methods: We used size exclusion chromatography, where molecules are separated according to their hydrodynamic radius to see if the VSG is present as a homodimer at both pH values. To gain information about the structural integrity of the protein we used circular dichroism spectroscopy by exposing the VSG in solution to a mixture of right- and left-circularly polarized light and analysing the absorbed UV spectra. Evaluation of protein stability and molecular dynamics simulations at different pH values was performed using different computational methods. Results: We show, for an A2-type VSG, that the dimer size is only slightly larger at pH 5.2 than at pH 7.4. Moreover, the dimer was marginally more stable at lower pH due to the higher affinity (ΔG = 353.37 kcal/mol) between the monomers. Due to the larger size, the predicted epitopes were more exposed to the solvent at low pH. Moderate conformational changes (ΔRMSD = 0.35 nm) in VSG were detected between the dimers at pH 5.2 and pH 7.4 in molecular dynamics simulations, and no significant differences in the protein secondary structure were observed by circular dichroism spectroscopy. Conclusions: Thus, the dissociation of anti-VSG-antibodies in endosomes cannot be explained by changes in pH.

Continuous endosomes form functional subdomains and orchestrate rapid membrane trafficking in trypanosomes.

Endocytosis is a common process observed in most eukaryotic cells, although its complexity varies among different organisms. In Trypanosoma brucei, the endocytic machinery is under special selective pressure because rapid membrane recycling is essential for immune evasion. This unicellular parasite effectively removes host antibodies from its cell surface through hydrodynamic drag and fast endocytic internalization. The entire process of membrane recycling occurs exclusively through the flagellar pocket, an extracellular organelle situated at the posterior pole of the spindle-shaped cell. The high-speed dynamics of membrane flux in trypanosomes do not seem compatible with the conventional concept of distinct compartments for early endosomes (EE), late endosomes (LE), and recycling endosomes (RE). To investigate the underlying structural basis for the remarkably fast membrane traffic in trypanosomes, we employed advanced techniques in light and electron microscopy to examine the three-dimensional architecture of the endosomal system. Our findings reveal that the endosomal system in trypanosomes exhibits a remarkably intricate structure. Instead of being compartmentalized, it constitutes a continuous membrane system, with specific functions of the endosome segregated into membrane subdomains enriched with classical markers for EE, LE, and RE. These membrane subdomains can partly overlap or are interspersed with areas that are negative for endosomal markers. This continuous endosome allows fast membrane flux by facilitated diffusion that is not slowed by multiple fission and fusion events.