Gut-associated functions are favored during microbiome assembly across a major part of C. elegans life

The microbiome expresses a variety of functions that influence host biology. The range of functions depends on the microbiome's composition, which can change during the host's lifetime due to neutral assembly processes, host-mediated selection, and environmental conditions. To date, the exact dynamics of microbiome assembly, the underlying determinants, and the effects on host-associated functions remain poorly understood. Here, we used the nematode Caenorhabditis elegans and a defined community of fully sequenced, naturally associated bacteria to study microbiome dynamics and functions across a major part of the worm's lifetime of hosts under controlled experimental conditions. Bacterial community composition initially shows strongly declining levels of stochasticity, which increases during later time points, suggesting selective effects in younger animals as opposed to more random processes in older animals. The adult microbiome is enriched in genera Ochrobactrum and Enterobacter compared to the direct substrate and a host-free control environment. Using pathway analysis, metabolic, and ecological modeling, we further find that the lifetime assembly dynamics increase competitive strategies and gut-associated functions in the host-associated microbiome, indicating that the colonizing bacteria benefit the worm. Overall, our study introduces a framework for studying microbiome assembly dynamics based on stochastic, ecological, and metabolic models, yielding new insights into the processes that determine host-associated microbiome composition and function.

IMPORTANCE

The microbiome plays a crucial role in host biology. Its functions depend on the microbiome composition that can change during a host's lifetime. To date, the dynamics of microbiome assembly and the resulting functions still need to be better understood. This study introduces a new approach to characterize the functional consequences of microbiome assembly by modeling both the relevance of stochastic processes and metabolic characteristics of microbial community changes. The approach was applied to experimental time-series data obtained for the microbiome of the nematode Caenorhabditis elegans across the major part of its lifetime. Stochastic processes played a minor role, whereas beneficial bacteria as well as gut-associated functions enriched in hosts. This indicates that the host might actively shape the composition of its microbiome. Overall, this study provides a framework for studying microbiome assembly dynamics and yields new insights into C. elegans microbiome functions.

The archaeome in metaorganism research, with a focus on marine models and their bacteria-archaea interactions

Metaorganism research contributes substantially to our understanding of the interaction between microbes and their hosts, as well as their co-evolution. Most research is currently focused on the bacterial community, while archaea often remain at the sidelines of metaorganism-related research. Here, we describe the archaeome of a total of eleven classical and emerging multicellular model organisms across the phylogenetic tree of life. To determine the microbial community composition of each host, we utilized a combination of archaea and bacteria-specific 16S rRNA gene amplicons. Members of the two prokaryotic domains were described regarding their community composition, diversity, and richness in each multicellular host. Moreover, association with specific hosts and possible interaction partners between the bacterial and archaeal communities were determined for the marine models. Our data show that the archaeome in marine hosts predominantly consists of Nitrosopumilaceae and Nanoarchaeota, which represent keystone taxa among the porifera. The presence of an archaeome in the terrestrial hosts varies substantially. With respect to abundant archaeal taxa, they harbor a higher proportion of methanoarchaea over the aquatic environment. We find that the archaeal community is much less diverse than its bacterial counterpart. Archaeal amplicon sequence variants are usually host-specific, suggesting adaptation through co-evolution with the host. While bacterial richness was higher in the aquatic than the terrestrial hosts, a significant difference in diversity and richness between these groups could not be observed in the archaeal dataset. Our data show a large proportion of unclassifiable archaeal taxa, highlighting the need for improved cultivation efforts and expanded databases.

Metabolic model predictions enable targeted microbiome manipulation through precision prebiotics

While numerous health-beneficial interactions between host and microbiota have been identified, there is still a lack of targeted approaches for modulating these interactions. Thus, we here identify precision prebiotics that specifically modulate the abundance of a microbiome member species of interest. In the first step, we show that defining precision prebiotics by compounds that are only taken up by the target species but no other species in a community is usually not possible due to overlapping metabolic niches. Subsequently, we use metabolic modeling to identify precision prebiotics for a two-member Caenorhabditis elegans microbiome community comprising the immune-protective target species Pseudomonas lurida MYb11 and the persistent colonizer Ochrobactrum vermis MYb71. We experimentally confirm four of the predicted precision prebiotics, L-serine, L-threonine, D-mannitol, and γ-aminobutyric acid, to specifically increase the abundance of MYb11. L-serine was further assessed in vivo, leading to an increase in MYb11 abundance also in the worm host. Overall, our findings demonstrate that metabolic modeling is an effective tool for the design of precision prebiotics as an important cornerstone for future microbiome-targeted therapies.IMPORTANCEWhile various mechanisms through which the microbiome influences disease processes in the host have been identified, there are still only few approaches that allow for targeted manipulation of microbiome composition as a first step toward microbiome-based therapies. Here, we propose the concept of precision prebiotics that allow to boost the abundance of already resident health-beneficial microbial species in a microbiome. We present a constraint-based modeling pipeline to predict precision prebiotics for a minimal microbial community in the worm Caenorhabditis elegans comprising the host-beneficial Pseudomonas lurida MYb11 and the persistent colonizer Ochrobactrum vermis MYb71 with the aim to boost the growth of MYb11. Experimentally testing four of the predicted precision prebiotics, we confirm that they are specifically able to increase the abundance of MYb11 in vitro and in vivo. These results demonstrate that constraint-based modeling could be an important tool for the development of targeted microbiome-based therapies against human diseases.

The intricate triangular interaction between protective microbe, pathogen and host determines fitness of the metaorganism

The microbiota shapes host biology in numerous ways. One example is protection against pathogens, which is likely critical for host fitness in consideration of the ubiquity of pathogens. The host itself can affect abundance of microbiota or pathogens, which has usually been characterized in separate studies. To date, however, it is unclear how the host influences the interaction with both simultaneously and how this triangular interaction determines fitness of the host-microbe assemblage, the so-called metaorganism. To address this current knowledge gap, we focused on a triangular model interaction, consisting of the nematode Caenorhabditis elegans, its protective symbiont Pseudomonas lurida MYb11 and its pathogen Bacillus thuringiensis Bt679. We combined the two microbes with C. elegans mutants with altered immunity and/or microbial colonization, and found that (i) under pathogen stress, immunocompetence has a larger influence on metaorganism fitness than colonization with the protective microbe; (ii) in almost all cases, MYb11 still improves fitness; and (iii) disruption of p38 MAPK signalling, which contributes centrally to immunity against Bt679, completely reverses the protective effect of MYb11, which further reduces nematode survival and fitness upon infection with Bt679. Our study highlights the complex interplay between host, protective microbe and pathogen in shaping metaorganism biology.

Effect of Indian clubbell exercises on cricket fast bowlers' shoulder kinematics

Background

The glenohumeral joint's rotational range of motion (ROM) and muscle strength are essential to execute the cricket bowling action. Performing shoulder rotation exercises may increase the rotator cuff muscle strength and rotational ROM.

Objectives

The aim of this study was to test the effect of a six-week exercise programme on shoulder rotational ROM and muscle strength.

Methods

Twenty-one healthy male cricket fast bowlers were recruited, ranked and pair-matched on initial shoulder rotator muscle strength and assigned to either a shoulder exercise (SE) group or cricket training (CT) only group. The SE group incorporated Indian clubbell exercises in addition to their cricket training.

Results

Bowlers in both groups displayed a large increase on the dominant shoulder's internal rotation (IR) ROM, but only the SE group's bowlers displayed ROM improvements (p<0.001) bilaterally for both internal and external rotation. The CT group's fast bowler's non-dominant shoulder IR ROM significantly decreased (p=0.02) during the six weeks. Between groups, only the SE group's bowler's internal rotator muscle strength improved (p<0.001) bilaterally. The observed kinematic changes were statistically significantly greater at a 5% level for the SE group's bowlers (bilateral internal rotators muscle strength, non-dominant shoulder IR ROM and horizontal adduction ROM).

Conclusion

Maintenance of the shoulder's rotational ROM and muscle strength is vital for a fast bowler. Cricket bowlers who perform regular clubbell exercises might increase their shoulder's ROM and internal rotator cuffs' muscle strength, which may aid in stabilising their glenohumeral joint while bowling.

Host and microbiome jointly contribute to environmental adaptation

Most animals and plants have associated microorganisms, collectively referred to as their microbiomes, which can provide essential functions. Given their importance, host-associated microbiomes have the potential to contribute substantially to adaptation of the host-microbiome assemblage (the "metaorganism"). Microbiomes may be especially important for rapid adaptation to novel environments because microbiomes can change more rapidly than host genomes. However, it is not well understood how hosts and microbiomes jointly contribute to metaorganism adaptation. We developed a model system with which to disentangle the contributions of hosts and microbiomes to metaorganism adaptation. We established replicate mesocosms containing the nematode Caenorhabditis elegans co-cultured with microorganisms in a novel complex environment (laboratory compost). After approximately 30 nematode generations (100 days), we harvested worm populations and associated microbiomes, and subjected them to a common garden experiment designed to unravel the impacts of microbiome composition and host genetics on metaorganism adaptation. We observed that adaptation took different trajectories in different mesocosm lines, with some increasing in fitness and others decreasing, and that interactions between host and microbiome played an important role in these contrasting evolutionary paths. We chose two exemplary mesocosms (one with a fitness increase and one with a decrease) for detailed study. For each example, we identified specific changes in both microbiome composition (for both bacteria and fungi) and nematode gene expression associated with each change in fitness. Our study provides experimental evidence that adaptation to a novel environment can be jointly influenced by host and microbiome.

Irradiation Dose to the Swallowing Muscles Impacts Nutritional Status in Head and Neck Cancer Patients: The Prospective Randomized HEADNUT Trial

PURPOSE/OBJECTIVE(S)

To evaluate the influence of radiation dose on swallowing muscles and associated side effects as well as on nutritional status in patients with head and neck cancer undergoing primary or adjuvant (chemo)radiotherapy.

MATERIALS/METHODS

Between 2018 and 2020, sixty-one patients were prospectively randomized into the so-called HEADNUT-trial (HEAD and neck cancer patients undergoing NUTritional intervention). Follow-up was continued until 2022. Contouring of the swallowing apparatus included and the swallowing muscles with the superior (scm), middle (mcm), and inferior constrictor muscle (icm), the cricopharyngeal muscle and the inlet of the esophagus. Nutritional status was assessed by bioelectrical impedance analysis (BIA) at the beginning and the end of radiotherapy. The post-therapeutic nutritional status was evaluated by the BIA-derived FFMI (fat-free mass index; kg/m²). Malnutrition was assumed at FFMI values of <15 (♀) and <17 (♂) kg/m². To find differences between dosimetric parameters in well- and malnourished patients, Mann-Whitney-U-test was used. To estimate the relationship between malnutrition and its influencing variables a logistic regression model was built.

RESULTS

The following structures differed between well- and malnourished patients at the end of therapy: icm (Dmean, V40Gy (%), V50Gy (%), V60Gy (%)) and cricopharyngeal muscle (V40Gy (%)). After entering these parameters into a multivariable logistic regression model icm Dmean (b = -0.12; Exp(b) = 0.88; 95%-CI: 0.78-1.0; p = 0.06) and icm V40Gy (%) (b = 0.06; Exp(b) = 1.07; 95%-CI: 1-1.13; p = 0.04) proved to be independent predictors of malnutrition. We only determined the cut-off value for icm V40Gy (%) since it was the only parameter which met p<0.05. The optimal cut-off value for the predictor V40Gy (%) based on the Youden Index was 85.6%.

CONCLUSION

Adherence to dose constraints for the swallowing apparatus may prevent malnutrition in head and neck cancer patients at the end of therapy. Specifically, we suggest an icm V40Gy (%) of more than 86% being predictive for nutritional complications.

Metabolic model predictions enable targeted microbiome manipulation through precision prebiotics

The microbiome is increasingly receiving attention as an important modulator of host health and disease. However, while numerous mechanisms through which the microbiome influences its host have been identified, there is still a lack of approaches that allow to specifically modulate the abundance of individual microbes or microbial functions of interest. Moreover, current approaches for microbiome manipulation such as fecal transfers often entail a non-specific transfer of entire microbial communities with potentially unwanted side effects. To overcome this limitation, we here propose the concept of precision prebiotics that specifically modulate the abundance of a microbiome member species of interest. In a first step, we show that defining precision prebiotics by compounds that are only taken up by the target species but no other species in a community is usually not possible due to overlapping metabolic niches. Subsequently, we present a metabolic modeling network framework that allows us to define precision prebiotics for a two-member C. elegans microbiome model community comprising the immune-protective Pseudomonas lurida MYb11 and the persistent colonizer Ochrobactrum vermis MYb71. Thus, we predicted compounds that specifically boost the abundance of the host-beneficial MYb11, four of which were experimentally validated in vitro (L-serine, L-threonine, D-mannitol, and γ-aminobutyric acid). L-serine was further assessed in vivo, leading to an increase in MYb11 abundance also in the worm host. Overall, our findings demonstrate that constraint-based metabolic modeling is an effective tool for the design of precision prebiotics as an important cornerstone for future microbiome-targeted therapies.

The nematode Caenorhabditis elegans and diverse potential invertebrate vectors predominantly interact opportunistically

Some small animals migrate with the help of other, more mobile animals (phoresy) to leave short-lived and resource-poor habitats. The nematode Caenorhabditis elegans lives in ephemeral habitats such as compost, but has also been found associated with various potential invertebrate vectors. Little research has been done to determine if C. elegans is directly attracted to these invertebrates. To determine whether C. elegans is attracted to compounds and volatile odorants of invertebrates, we conducted chemotaxis experiments with the isopods Porcellio scaber, Oniscus asellus, and Armadillidium sp. and with Lithobius sp. myriapods, Drosophila melanogaster fruit flies, and Arion sp. slugs as representatives of natural vectors. Because phoresy is an important escape strategy in nature, especially for dauer larvae of C. elegans, we examined the attraction of the natural C. elegans isolate MY2079 in addition to the laboratory-adapted strain N2 at the dauer and L4 stage. We found that DMSO washing solution of Lithobius sp. and the odor of live D. melanogaster attracted C. elegans N2 L4 larvae. Surprisingly, the natural isolate MY2079 was not attracted to any invertebrate during either the dauer or L4 life stages and both C. elegans strains were repelled by various compounds from O. asellus, P. scaber, Armadillidium sp., Lithobius sp., and Arion sp. feces. We hypothesize that this is due to defense chemicals released by the invertebrates. Although compounds from Lithobius sp. and D. melanogaster odorants were mildly attractive, the lack of attraction to most invertebrates suggests a predominantly opportunistic association between C. elegans and invertebrate vectors.

Prognostic impact of echocardiographic derived precapillary wedge pressure and pulmonary vascular resistances in patients with heart failure

Background

A reliable echocardiographic algorithm for the estimation of precapillary wedge pressure (PCWP) and pulmonary vascular resistances (PVR) has been recently validated by our group in a large cohort of patients undergoing right heart catheterization (RHC) (1). Those metrics may add relevant clinical and prognostic information in patients with heart failure (HF).

Objective

To assess the clinical/prognostic significance of echocardiographic derived PCWP and PVR in a large cohort of chronic HF patients on modern treatments.

Methods

Outpatients with chronic HF with either reduced (≤40%) or mildly reduced LVEF (41–49%) underwent a thorough clinical multiparametric assessment and were followed-up for a composite endpoint of cardiac death, appropriate ICD shock, or first HF hospitalization.

Results

Out of 1,483 patients prospectively enrolled (70±12 years, 73% males, 42% ischemic etiology, LVEF 35±8%), PCWP (16.4±5.8 mmHg) was elevated (&gt;15 mmHg) in 53% of cases, while PVR (1.7±0.7) was elevated (&gt;3 WU) in 6% of cases. Of the latter group, most (92%) had also elevated PCWP. Patients with increased PCWP were older, had a higher heart rate and lower cardiac output, showed a higher degree of left and right chamber remodeling, had a higher neurohormonal activation, worse renal function, worse functional capacity and ventilatory efficiency on effort (all p&lt;0.001). Those patients with high PCWP and PVR showed higher heart rate and pulmonary pressures, lower cardiac output, and right ventricular function, higher neurohormonal activation, lower functional capacity and ventilatory efficiency on effort compared to patients with high PCWP but normal PVR (all p&lt;0.01). The optimal prognostic cut-point was identified for both PCWP (16.2 mmHg) and PVR (2 WU) by log-rank maximal likelihood ratio. Over a median follow-up of 22 (8–37) months, both measures significantly stratified patients for the risk of the primary endpoint at Kaplan-Meier analysis (log-rank 92.9, p&lt;0.001 for PCWP; log-rank 17.3, p&lt;0.001 for PVR). At multivariable Cox regression analysis (adjusted for age, sex, ischemic HF etiology, renal function, LVEF, and NT-proBNP), PCWP (hazard ratio, HR 1.77 [95% CI 1.30–2.40], p&lt;0.001) but not PVR (HR 1.15 [95% CI 0.88–1.51], p=0.31) remained an independent predictor of the primary outcome.

Conclusion

The estimation of PCWP and PVR by echocardiography add relevant clinical and prognostic information and may help in the decision making in patients with HF.

Funding Acknowledgement

Type of funding sources: None.

Valve disease in cardiac amyloidosis: an echocardiographic score

Background

Cardiac amyloidosis (CA) may affect all cardiac structures, including the valves.

Methods

From 423 patients undergoing a diagnostic workup for CA we selected 2 samples of 20 patients with amyloid transthyretin (ATTR-) or light-chain (AL-) CA, and age- and sex-matched controls. We chose 31 echocardiographic items related to the mitral, aortic and tricuspid valves, giving a value of 1 to each abnormal item.

Results

Patients with ATTR-CA displayed more often a shortened/hidden and restricted posterior mitral valve leaflet (PMVL), thickened mitral chordae tendineae and aortic stenosis than those with AL-CA, and less frequent PMVL calcification than matched controls. Score values were 15.8 (13.6–17.4) in ATTR-CA, 11.0 (9.3–14.9) in AL-CA, 12.8 (11.1–14.4) in ATTR-CA controls, and 11.0 (9.1–13.0) in AL-CA controls (p=0.004 for ATTR- vs. AL-CA, 0.009 for ATTR-CA vs. their controls, and 0.461 for AL-CA vs. controls). Area under the curve values to diagnose ATTR-CA were 0.782 in patients with ATTR-CA or matched controls, and 0.773 in patients with LV hypertrophy.

Conclusions

Patients with ATTR-CA have a prominent impairment of mitral valve structure and function, and higher score values. The valve score is quite effective in identifying patients with ATTR-CA among patients with CA or unexplained hypertrophy.

Funding Acknowledgement

Type of funding sources: None.

Clinical and prognostic significance of left ventricular outflow tract velocity time integral (LVOT-VTI) in patients with chronic heart failure

Background

The echocardiographic evaluation of cardiac output relies on the product of the flow across the left ventricular outflow tract (LVOT), estimated through its velocity time integral (LVOT-VTI), and its cross-sectional area, estimated through the formula πr2. Considering the geometrical assumption behind such formula, LVOT-VTI has been proposed as a more reproducible surrogate of cardiac systolic function and showed prognostic value in the critical care setting. However, the role of such measure in patients with chronic heart failure (HF) remains unexplored.

Objective

To assess the clinical and prognostic significance of LVOT-VTI in a contemporary cohort of patients with chronic HF.

Methods

Outpatients with chronic HF with a LV ejection fraction &lt;50% were prospectively enrolled to undergo a clinical, echocardiographic, and biohumoral assessment, and were followed-up for the endpoint of all-cause death.

Results

Finally, 971 patients were enrolled (71±12 years, 72% men, 50% ischemic etiology, LVEF 35±9%). Most patients showed a NYHA class I-II (74%) and were treated with ACE-inhibitors/ARBs or ARNI (81%), beta-blockers (95%), and mineralocorticoid receptor antagonists (71%). Patients were distinguished in three subgroups according to LVOT-VTI tertiles &lt;19 (n=324), 19–24 (n=324), or ≥24 (n=323). Compared with the other two subgroups, patients with LVOT-VTI &lt;19 showed worse NYHA class, lower LVEF and tricuspid annular plane systolic excursion (TAPSE), and higher E/e', left atrial volume index (LAVi), estimated systolic pulmonary arterial pressure (sPAP), and NT-proBNP concentration (all p&lt;0.001). No differences were observed as for patients' age, HF etiology, and therapies (all p&gt;0.05). Over a median follow-up of 22 (9–34) months, 103 (11%) patients met the primary endpoint. LVOT-VTI significantly stratified the risk of death, observing 65 (20%), 21 (7%), and 17 (5%) events across the subgroups with values &lt;19, 19–24, or ≥24 (log-rank 33, p&lt;0.001). At multivariable regression analysis, LVOT-VTI &lt;19 (HR 2.06 [95% 1.21–3.49], p=0.008), but not LVEF &lt;30% (p=0.614) was an independent predictor of all-cause death in a model adjusted for age, sex, ischemic etiology, renal function, hemoglobin, E/e', LAVi, TAPSE, sPAP, and NT-proBNP.

Conclusion

LVOT-VTI is associated with disease severity and is a strong predictor of all-cause death in patients with chronic HF.

Funding Acknowledgement

Type of funding sources: None.

C42 MULTI–CHAMBER SPECKLE TRACKING IMAGING AND DIAGNOSTIC VALUE OF LEFT ATRIAL STRAIN IN CARDIAC AMYLOIDOSIS

Background

Amyloid deposits in all cardiac chambers, impairing their function. We investigated for the first time if a speckle–tracking echocardiography (STE) analysis extended to all 4 chambers might hold additive diagnostic value for CA and its subtypes (amyloid transthyretin [ATTR–] and light–chain [AL]–CA).

Methods

We evaluated 423 consecutive patients undergoing a diagnostic workup for CA in 2 referral centres from 2015 to 2020.

Results

CA was diagnosed in 261 patients (62%; ATTR–CA, n = 144, 34%; AL–CA, n = 117, 28%). Patients with CA had an impaired function of all cardiac chambers, particularly those with ATTR–CA. Peak left atrial longitudinal strain (LA–PALS) was the only STE parameter that predicted CA and ATTR–CA independent of laboratory and standard echocardiographic variables (Model 1). It also predicted ATTR–CA among patients with unexplained hypertrophy regardless of a diagnostic score (IWT score). Patients with either LA–PALS or LA–peak atrial contraction strain (PACS) in the first quartile (LA–PALS &lt;6.65% or LA–PACS &lt;3.62%) had an almost 4–fold higher likelihood of CA and ATTR–CA regardless of Model 1. Among patients with unexplained hypertrophy, those with LA–PALS or LA–PACS in the first quartile had an almost 9–fold higher likelihood of ATTR–CA irrespective of Model 1, and a 2–fold higher likelihood of ATTR–CA beyond the IWT score.

Conclusions

STE measures of all 4 chambers are abnormal in patients with CA, particularly in those with ATTR–CA. LA strain holds independent diagnostic significance. Among patients screened for CA, those with LA–PALS &lt;6.65% and/or LA–PACS &lt;3.62% have a high likelihood of CA and ATTR–CA.

P294 AN ECHOCARDIOGRAPHIC SCORE OF VALVE DISEASE IN PATIENTS WITH CARDIAC AMYLOIDOSIS

Background

Cardiac amyloidosis (CA) affects all cardiac structures, including the valves. We summarized the echocardiographic features of valve disease in a score.

Methods

From 423 patients undergoing a diagnostic workup for CA we selected 2 samples of 20 patients with amyloid transthyretin (ATTR–) or light–chain (AL–) CA, and selected age– and sex–matched controls. The Amyloid VAlve (AVA) score included 31 items related to the mitral, aortic and tricuspid valves (which can be properly assessed in standard echocardiograms), with a value of 1 for each abnormal item.

Results

Patients with ATTR–CA displayed more often a shortened/hidden and retracted posterior mitral valve leaflet (PMVL), thickened mitral chordae tendineae and aortic stenosis than those with AL–CA, and less frequent PMVL calcification than matched controls. Score values were 15.8 (interquartile interval 13.6–17.4) in ATTR–CA, 11.0 (9.3–14.9) in AL–CA, 12.8 (11.1–14.4) in ATTR–CA controls, and 11.0 (9.1–13.0) in AL–CA controls (p = 0.004 for ATTR– vs. AL–CA, 0.009 for ATTR–CA vs. their controls, and 0.461 for AL–CA vs. controls). We compared the AVA and two validated diagnostic scores (IWT and AMYLI). AUC values for the diagnosis of ATTR–CA were 0.782, 0.846 and 0.902, respectively, in patients with ATTR–CA or matched controls, and 0.773, 0.706 and 0.679 in patients with LV hypertrophy (n = 67, 84%) (all non–significant p values).

Conclusions

Patients with ATTR–CA have a prominent impairment of mitral valve structure and function, and higher score values. The AVA score is quite effective in identifying patients with ATTR–CA among patients with CA or with unexplained hypertrophy.

Preconditioning With Natural Microbiota Strain Ochrobactrum vermis MYb71 Influences Caenorhabditis elegans Behavior

In comparison with the standard monoxenic maintenance in the laboratory, rearing the nematode Caenorhabditis elegans on its natural microbiota improves its fitness and immunity against pathogens. Although C. elegans is known to exhibit choice behavior and pathogen avoidance behavior, little is known about whether C. elegans actively chooses its (beneficial) microbiota and whether the microbiota influences worm behavior. We examined eleven natural C. elegans isolates in a multiple-choice experiment for their choice behavior toward four natural microbiota bacteria and found that microbiota choice varied among C. elegans isolates. The natural C. elegans isolate MY2079 changed its choice behavior toward microbiota isolate Ochrobactrum vermis MYb71 in both multiple-choice and binary-choice experiments, in particular on proliferating bacteria: O. vermis MYb71 was chosen less than other microbiota bacteria or OP50, but only after preconditioning with MYb71. Examining escape behavior and worm fitness on MYb71, we ruled out pathogenicity of MYb71 and consequently learned pathogen avoidance behavior as the main driver of the behavioral change toward MYb71. The change in behavior of C. elegans MY2079 toward microbiota bacterium MYb71 demonstrates how the microbiota influences the worm's choice. These results might give a baseline for future research on host-microbiota interaction in the C. elegans model.

Integration of radiation oncology teaching in medical studies by German medical faculties due to the new licensing regulations : An overview and recommendations of the consortium academic radiation oncology of the German Society for Radiation Oncology (DEGRO)

The new Medical Licensing Regulations 2025 (Ärztliche Approbationsordnung, ÄApprO) will soon be passed by the Federal Council (Bundesrat) and will be implemented step by step by the individual faculties in the coming months. The further development of medical studies essentially involves an orientation from fact-based to competence-based learning and focuses on practical, longitudinal and interdisciplinary training. Radiation oncology and radiation therapy are important components of therapeutic oncology and are of great importance for public health, both clinically and epidemiologically, and therefore should be given appropriate attention in medical education. This report is based on a recent survey on the current state of radiation therapy teaching at university hospitals in Germany as well as the contents of the National Competence Based Learning Objectives Catalogue for Medicine 2.0 (Nationaler Kompetenzbasierter Lernzielkatalog Medizin 2.0, NKLM) and the closely related Subject Catalogue (Gegenstandskatalog, GK) of the Institute for Medical and Pharmaceutical Examination Questions (Institut für Medizinische und Pharmazeutische Prüfungsfragen, IMPP). The current recommendations of the German Society for Radiation Oncology (Deutsche Gesellschaft für Radioonkologie, DEGRO) regarding topics, scope and rationale for the establishment of radiation oncology teaching at the respective faculties are also included.

Left atrial strain in cardiac amyloidosis

Background

Patients with cardiac amyloidosis (CA) display an enlarged and dysfunctional left atrium (LA), because of the effects of left ventricular (LV) diastolic and then systolic dysfunction, as well as the amyloid infiltration of LA wall. A single study reported impaired LA strain in CA, but differences among amyloid light-chain (AL) and transthyretin (ATTR) CA and the correlates of reduced LA strain have not been characterized.

Methods

We evaluated 426 consecutive patients undergoing a screening for suspected CA in 2 tertiary referral centres. Among them, 262 (61%) were diagnosed with CA (n=117 AL-CA, n=145 ATTR-CA). We measured peak atrial longitudinal strain (PALS) and peak atrial contraction strain (PACS) from 4- and 2-chamber (4C, 2C) views, and correlated them with maximum and minimum LA volumes, E/e' ratio, and LV global longitudinal strain (GLS).

Results

LA strain was much more severely impaired in patients with ATTR-CA than those without CA, and to a lesser extent than those with AL-CA (Figure). LA volumes were larger in patients with ATTR-CA than those without CA (maximal LA volume, p=0.042; minimal LA volume, p&lt;0.001), and those with AL-CA (both volumes, p&lt;0.001). LA strain values were more closely correlated with minimal than maximal LA volumes, and patients with AL-CA displayed stronger correlations than those with ATTR-CA or without CA; for example, Spearman's rho values for 4C-PALS vs. minimal LA volume were 0.595, 0.481, and 0.462, respectively (all p&lt;0.001). Furthermore, LA strain correlated with E/e' in patients with AL-CA, but not in those with ATTR-CA: 4C-PALS vs. E/e', rho 0.406, p=0.001 (AL-CA), p=0.401 (ATTR-CA), and p=0.097 (no CA). Finally, LA strain correlated most closely with LV GLS in patients with AL-CA: 4C-PALS vs. LV GLS, rho 0.431, p&lt;0.001 (AL-CA), rho 0.401, p&lt;0.001 (ATTR-CA), rho 0.219, p=0.042 (no CA).

Conclusions

LA volume increase and reduced LA strain is particularly prominent in patients with ATTR-CA. Patients with AL-CA seem to display closer relationships between LA strain, size and haemodynamic load, possibly reflecting the most acute disease course, and lower time for amyloid deposition in the LA wall.

Funding Acknowledgement

Type of funding sources: None.

Reverse remodelling criteria to predict cardiovascular death in heart failure with reduced or mid-range ejection fraction

Aims

Reverse remodelling (RR) is the recovery from left ventricle (LV) dilatation and dysfunction. There are no established definitions of RR. We sought to identify RR criteria that better predicted cardiovascular death.

Methods and results

Forty-two studies used 25 criteria to define RR, most commonly (n=12) as LV end-systolic volume (LVESV) reduction ≥15%. We evaluated 927 patients with LV ejection fraction (LVEF) &lt;50% undergoing 2 echocardiograms within 12±2 months. Over a median 2.8-year follow-up after the second echocardiogram (1.3–4.9), 123 cardiovascular deaths occurred (13%). Model 1 included age, LVEF, N-terminal pro-B-type natriuretic peptide (NT-proBNP), ischaemic aetiology, cardiac resynchronization therapy (CRT), estimated glomerular filtration rate (eGFR), New York Heart Association (NYHA), and LVESV index (LVESVi), and Model 2 the validated 3C-HF score. Two RR criteria proved particularly effective in risk reclassification over Model 1 and Model 2: LVEF increase ≥1 category (severe [LVEF ≤30%], moderate [LVEF 31–40%], mild LV dysfunction [LVEF 41–55%] and normal LV function [LVEF ≥56%]), and LVEF increase &gt;10 U. The same 2 criteria yielded independent prognostic significance and improved reclassification also in patients with LVEF &lt;40% or LVEF ≤35%. LVEF increase ≥1 category and LVEF increase &gt;10 U displayed a stronger prognostic value than LVESV reduction ≥15%, both in the whole population and the subsets with LVEF &lt;40% or ≤35%.

Funding Acknowledgement

Type of funding sources: None.

Fungal quinones: diversity, producers, and applications of quinones from Aspergillus, Penicillium, Talaromyces, Fusarium, and Arthrinium

Quinones represent an important group of highly structurally diverse, mainly polyketide-derived secondary metabolites widely distributed among filamentous fungi. Many quinones have been reported to have important biological functions such as inhibition of bacteria or repression of the immune response in insects. Other quinones, such as ubiquinones are known to be essential molecules in cellular respiration, and many quinones are known to protect their producing organisms from exposure to sunlight. Most recently, quinones have also attracted a lot of industrial interest since their electron-donating and -accepting properties make them good candidates as electrolytes in redox flow batteries, like their often highly conjugated double bond systems make them attractive as pigments. On an industrial level, quinones are mainly synthesized from raw components in coal tar. However, the possibility of producing quinones by fungal cultivation has great prospects since fungi can often be grown in industrially scaled bioreactors, producing valuable metabolites on cheap substrates. In order to give a better overview of the secondary metabolite quinones produced by and shared between various fungi, mainly belonging to the genera Aspergillus, Penicillium, Talaromyces, Fusarium, and Arthrinium, this review categorizes quinones into families such as emodins, fumigatins, sorbicillinoids, yanuthones, and xanthomegnins, depending on structural similarities and information about the biosynthetic pathway from which they are derived, whenever applicable. The production of these quinone families is compared between the different genera, based on recently revised taxonomy. KEY POINTS: • Quinones represent an important group of secondary metabolites widely distributed in important fungal genera such as Aspergillus, Penicillium, Talaromyces, Fusarium, and Arthrinium. • Quinones are of industrial interest and can be used in pharmacology, as colorants and pigments, and as electrolytes in redox flow batteries. • Quinones are grouped into families and compared between genera according to the revised taxonomy.

Microbes to-go: slugs as source for Caenorhabditis elegans microbiota acquisition

Research on the Caenorhabditis elegans microbiota only recently started, with little known about how C. elegans acquires its microbiota. Slugs live in the same habitat as C. elegans and are known vectors for the worm. Hence, we wondered how the passage through a slug affects the C. elegans gut microbiota and whether worms can acquire bacteria from the slug. Using fluorescently labelled microbiota and 16S rRNA gene amplicon sequencing, we evaluated microbiota persistence and acquisition in C. elegans after slug passage. We compared C. elegans gut microbiomes isolated from wild-caught slugs to the microbiomes of worms after experimental slug passage to compare similarities and differences in microbiome composition. We found that microbiota persists in C. elegans while passing the slug gut and that worms simultaneously acquire additional bacteria species from the slug. Although the amplicon sequencing variant (ASV) richness of worms from the experiment did not exceed the richness of worms that naturally occur in slugs, we found a high number of shared ASVs indicating the importance of commonly associated microbiota. We demonstrate that C. elegans can take advantage of its passage through the slug by acquiring new potential microbiota without losing its native microbiota.

Effector and regulator: Diverse functions of C. elegans C-type lectin-like domain proteins

In C. elegans, 283 clec genes encode a highly diverse family of C-type lectin-like domain (CTLD) proteins. Since vertebrate CTLD proteins have characterized functions in defense responses against pathogens and since expression of C. elegans clec genes is pathogen-dependent, it is generally assumed that clec genes function in C. elegans immune defenses. However, little is known about the relative contribution and exact function of CLEC proteins in C. elegans immunity. Here, we focused on the C. elegans clec gene clec-4, whose expression is highly upregulated by pathogen infection, and its paralogs clec-41 and clec-42. We found that, while mutation of clec-4 resulted in enhanced resistance to the Gram-positive pathogen Bacillus thuringiensis MYBt18247 (Bt247), inactivation of clec-41 and clec-42 by RNAi enhanced susceptibility to Bt247. Further analyses revealed that enhanced resistance of clec-4 mutants to Bt247 was due to an increase in feeding cessation on the pathogen and consequently a decrease in pathogen load. Moreover, clec-4 mutants exhibited feeding deficits also on non-pathogenic bacteria that were in part reflected in the clec-4 gene expression profile, which overlapped with gene sets affected by starvation or mutation in nutrient sensing pathways. However, loss of CLEC-4 function only mildly affected life-history traits such as fertility, indicating that clec-4 mutants are not subjected to dietary restriction. While CLEC-4 function appears to be associated with the regulation of feeding behavior, we show that CLEC-41 and CLEC-42 proteins likely function as bona fide immune effector proteins that have bacterial binding and antimicrobial capacities. Together, our results exemplify functional diversification within clec gene paralogs.

C-type lectin-like domain (CTLD) containing proteins fulfill various and fundamental tasks in the human and mouse immune system. Genes encoding CTLD proteins are present in all animal genomes, in some cases in very large numbers and highly diversified. While the function of several vertebrate CTLD proteins is well characterized, experimental evidence of an immune function of most invertebrate CTLD proteins is missing, although their role in immunity is usually assumed. We here explore the immune function of three related CTLD proteins in the model nematode Caenorhabditis elegans. We find that they play diverse roles in C. elegans immunity, functioning as antimicrobial immune effector proteins that are important for defense against pathogen infection and probably directly interact with bacteria, but also regulators of feeding behavior that more indirectly affect C. elegans pathogen resistance. Such insight into the functional consequence of invertebrate CTLD protein diversification contributes to our understanding of the evolution of innate and invertebrate immune systems.

Fully automated counting of DNA damage foci in tumor cell culture: A matter of cell separation

Analysis and quantification of residual, unrepaired DNA double-strand breaks by detecting damage-associated γH2AX or 53BP1 foci is a promising approach to evaluate radiosensitivity or radiosensitization in tumor cells. Manual foci quantification by eye is well-established but unsatisfactory due to inconsistent foci numbers between different observers, lack of information about foci size and intensity and the time-consuming scoring process. Therefore, automated foci counting is an important goal. Several software solutions for automated foci counting in separately acquired fluorescence microscopy images have been established. The AKLIDES NUK technology by Medipan combines automated microscopy and image processing/ counting, enabling affordable high throughput foci analysis as a routine application. Using this machine, automated foci counting is well established for lymphocytes but has not yet been reported for adherent tumor cells with their irregularly shaped nuclei and heterogeneous foci textures. Here we aimed to use the AKLIDES NUK system for adherent tumor cells growing in clusters. We identified cell separation as a critical step to ensure fast and reliable automated nuclei detection. We validated our protocol for the fully automated quantification of (i) the IR-dose dependent increase and (ii) the ATM as well as PARP inhibitor-induced radiosensitization. Collectively, with this protocol the AKLIDES NUK system facilitates cost effective, fast and high throughput quantitative fluorescence microscopic analysis of DNA damage induced foci such as γH2AX and 53BP1 in adherent tumor cells.

Objective and subjective rapid frailty screening tools in people with HIV

OBJECTIVES

As people with HIV (PWH) age, the prevalence of frailty increases. Rapid screening tests to identify frailty within HIV outpatient settings are required to identify at-risk individuals. We undertook a service evaluation to assess three short frailty assessments in PWH.

METHODS

We assessed two objective [gait speed (GS), timed-up-and-go test (TUGT)] and one subjective [the self-reported health questionnaire (SRH)] frailty screening tools in PWH aged > 40 years attending a single HIV outpatient department. Factors associated with positive frailty screening tests (defined as GS < 0.8 m/s, TUGT ≥ 10 s and SRH score < 6) were assessed using logistic regression models.

ETHICAL CONSIDERATIONS

This was a service evaluation and was approved as a service evaluation by the Imperial College Healthcare NHS trust HIV clinical research committee (February 2020). All participants were given verbal information and were able to terminate the screening tests at any time.

RESULTS

Of 84 PWH approached, 80 individuals completed all screening tests (median age = 56 years, range: 40-80) with a positive frailty screening prevalence in 19%, 33% and 20% for GS, TUGT and SRH, respectively. All tests were considered acceptable to participants. Factors statistically significantly associated with frailty included age (GS and TUGT), detectable HIV RNA (TUGT), number of comorbidities (GS and TUGT), presence of polypharmacy (GS and TUGT) and total number of concomitant medication (GS and SRH).

CONCLUSIONS

Rates of positive screening tests for frailty are dependent on screening tool used, with all three tools being acceptable to participants. Objective measures of frailty screening (GS and TUGT) are more closely associated with clinical parameters than is a subjective measure of frailty screening (SRH).

Dietary Intervention Reverses Fatty Liver and Altered Gut Microbiota during Early-Life Undernutrition

Nonalcoholic fatty liver disease (NAFLD), largely studied as a condition of overnutrition, also presents in undernourished populations. Like NAFLD, undernutrition disrupts systemic metabolism and has been linked to gut microbiota dysbiosis. Indeed, chronic exposures to fecal microbes contribute to undernutrition pathology in regions with poor sanitation. Despite a growing prevalence of fatty liver disease, the influence of undernutrition and the gut microbiota remain largely unexplored. Here, we utilize an established murine model (C57BL/6J mice placed on a malnourished diet that received iterative Escherichia coli/Bacteroidales gavage [MBG mice]) that combines a protein/fat-deficient diet and iterative exposure to specific, fecal microbes. Fecal-oral contamination exacerbates triglyceride accumulation in undernourished mice. MBG livers exhibit diffuse lipidosis accompanied by striking shifts in fatty acid, glycerophospholipid, and retinol metabolism. Multiomic analyses revealed metabolomic pathways linked to the undernourished gut microbiome and hepatic steatosis, including phenylacetate metabolism. Intriguingly, fatty liver features were observed only in the early-life, but not adult, MBG model despite similar liver metabolomic profiles. Importantly, we demonstrate that dietary intervention largely mitigates aberrant metabolomic and microbiome features in MBG mice. These findings indicate a crucial window in early-life development that, when disrupted by nutritional deficiency, may significantly influence liver function. Our work provides a multifaceted study of how diet and gut microbes inform fatty liver progression and reversal during undernutrition.IMPORTANCE Nonalcoholic fatty liver disease (NAFLD) remains a global epidemic, but it is often studied in the context of obesity and aging. Nutritional deficits, however, also trigger hepatic steatosis, influencing health trajectories in undernourished pediatric populations. Here, we report that exposure to specific gut microbes impacts fatty liver pathology in mice fed a protein/fat-deficient diet. We utilize a multiomics approach to (i) characterize NAFLD in the context of early undernutrition and (ii) examine the impact of diet and gut microbes in the pathology and reversal of hepatic steatosis. We provide compelling evidence that an early-life, critical development window facilitates undernutrition-induced fatty liver pathology. Moreover, we demonstrate that sustained dietary intervention largely reverses fatty liver features and microbiome shifts observed during early-life malnutrition.

Influence of radiation dose to pharyngeal constrictor muscles on late dysphagia and quality of life in patients with locally advanced oropharyngeal carcinoma

BACKGROUND AND OBJECTIVE

Patients with oropharyngeal carcinoma (OPC) often have difficulty swallowing, which may affect quality of life (QoL). Radiation dose to constrictor muscles plays an important role.

METHODS

54 patients with locally advanced OPC were evaluated after intensity-modulated radiotherapy. Data were collected at standardized intervals using the EORTC questionnaires QLQ-C30 and QLQ-HN35 within two years. The pharyngeal constrictors (superior, middle, and inferior) were each contoured as an organ at risk. Influence of dose to the constrictors (≥55 Gy vs. <55 Gy) on late dysphagia and QoL was analyzed using the t‑test.

RESULTS

Late radiation-induced dysphagia depends significantly on the dose to the lower pharyngeal constrictor. At a dose of ≥55 Gy, 14 (64%) patients developed dysphagia grade ≤2 and 8 (36%) patients grade ≥3. At a dose of <55 Gy, the distribution at the end of radiotherapy (RT) was similar: 22 (69%) patients with dysphagia grade ≤2, 10 (31%) with grade ≥3. There was no dose-dependent difference in the severity of dysphagia in the acute phase (p = 0.989). There were differences 18 months after the end of RT: ≥55 Gy: 19 (86%) patients showed dysphagia grade ≤2; 3 (14%) grade ≥3. At <55 Gy, 31 (97%) patients developed grade ≤2, 1 (3%) grade ≥3 (18 months: p = 0.001; 24 months: p = 0.000). Late dysphagia is also dependent on the dose level of the middle constrictor muscle (6 months: p = 0.000; 12 months: p = 0.005, 18 months: p = 0.034). After 24 months, there was no significant difference (p = 0.374).

CONCLUSION

Radiation dose to the upper constrictor muscle appears to be of little relevance. The middle and lower constrictor should be given special consideration to avoid late dysphagia. Long-term QoL is independent on radiation dose.

The association between physical activity and self-reported health in older adults: lessons implied by lifestyle factors

Physical activity (PA) has been evidenced to be associated with self-reported health, but studies providing this evidence have failed to incorporate some relevant covariates, especially those pertinent to an African sample. This study examined the association between PA and self-reported health, with relevant lifestyle factors, comorbidities, and personal characteristics treated as covariates in this assessment. The study population was retired and working older people aged 60 years or more in Accra, Ghana. A total of 686 individuals responded to self-reported questionnaires. Pearson's chi-square test and binary logistic regression were used to present findings. Our data indicated that older adults who participated in moderate PA for more than 60 minutes were 7 times (OR=7,41; p=0,000) more likely to report good health compared with those who were active for less than 30 minutes. Similarly, those who participated in vigorous PA for 60 or more minutes were 5 times (OR=4,52; p=0,003) more likely to report good health compared with those who were active for less than 30 minutes. It is concluded that PA is likely to better enhance self-reported health when older people avoid sedentary behaviour, reduce their frequency of smoking, and modify their diet, but our covariate adjustment suggests that alcohol intake does not necessarily mar self-reported health.

Home-based color card screening for biliary atresia: the first steps for implementation of a nationwide newborn screening in Germany

INTRODUCTION

Biliary atresia is a rare neonatal disease and the most common indication for pediatric liver transplantation. Kasai portoenterostomy is the initial treatment, aiming to prevent liver transplantation. Beyond age at Kasai, few prognostic factors are known. Multiple countries have established screening methods to reduce the age at Kasai and recent analysis shows significant better outcomes for screening cohorts. In 2016, we established a decentralized stool color card screening in Lower Saxony and we present our first 2 years of experiences.

METHODS

In cooperation with a major German health insurance company and the Medical Association of Lower Saxony, we established the screening project, printed 120,000 color cards, and distributed them to all maternity hospitals. Program advertises were printed in newspapers and medical journals. After the first year, the project was evaluated. Thirty maternity hospitals and local practitioners were contacted via telephone, Internet, intranet, and pediatric journals.

RESULTS

One out of seventy-six maternity hospitals (1.3%) refused to participate in the screening. 30 hospitals (40%) were contacted and 93.5% of the interviewed staff reported that stool color cards were handed out regularly and discussed with the parents. Only 20% of local practitioners assessed neonatal cholestasis to be a relevant problem during daily practice, and 55% regarded a stool color card screening to be useful.

CONCLUSIONS

In the second year, we extended the screening project to outpatient maternity clinics. Based on the responses of local practitioners, we regard the voluntary screening as insufficient and we have contacted the Federal Joint Committee for the initiation of a nationwide obligatory stool color card screening.

The functional repertoire contained within the native microbiota of the model nematode Caenorhabditis elegans

The microbiota is generally assumed to have a substantial influence on the biology of multicellular organisms. The exact functional contributions of the microbes are often unclear and cannot be inferred easily from 16S rRNA genotyping, which is commonly used for taxonomic characterization of bacterial associates. In order to bridge this knowledge gap, we here analyzed the metabolic competences of the native microbiota of the model nematode Caenorhabditis elegans. We integrated whole-genome sequences of 77 bacterial microbiota members with metabolic modeling and experimental characterization of bacterial physiology. We found that, as a community, the microbiota can synthesize all essential nutrients for C. elegans. Both metabolic models and experimental analyses revealed that nutrient context can influence how bacteria interact within the microbiota. We identified key bacterial traits that are likely to influence the microbe’s ability to colonize C. elegans (i.e., the ability of bacteria for pyruvate fermentation to acetoin) and affect nematode fitness (i.e., bacterial competence for hydroxyproline degradation). Considering that the microbiota is usually neglected in C. elegans research, the resource presented here will help our understanding of this nematode’s biology in a more natural context. Our integrative approach moreover provides a novel, general framework to characterize microbiota-mediated functions.

[Staging of liver fibrosis in biliary atresia : Comparison of Chevallier and Ishak score as well as automated evaluation]

BACKGROUND

Biliary atresia (BA) is a rare disease of the newborn, resulting in liver cirrhosis due to obliterative cholangiopathy. Liver biopsies are commonly performed in order to confirm the diagnosis and in order to stage fibrosis.

OBJECTIVES

The present study intended to analyze two established scores for evaluating liver fibrosis focusing on the interobserver variability as well as the prognostic reliability towards the time of liver transplantation.

MATERIALS AND METHODS

Liver biopsies of BA patients between 2012 and 2015 were evaluated retrospectively by two pathologists at the Hannover Medical School (MHH) and the RWTH Aachen University Hospital. Fibrosis was measured using Ishak and Chevallier scores. Furthermore, a computerized automatically algorithm-based analyzation (ABAA) was performed. Results were evaluated towards the time point of liver transplantation and hepatoportoenterostomy (HPE).

RESULTS

Overall, 34 liver biopsies were analyzed. The Ishak score showed a remarkable interobserver variability (Κ_W = 0.68) while the Chevallier score was proven to have a poor interobserver variability (Fleiss' Κappa = -0.01). However, both scores were correlated positively, as was the ABAA (p < 0.001). Regarding prognostic reliability, ROC analyses of the Ishak score revealed the best validity towards an early liver transplantation within 12 months (AUC 0.813, p = 0.011). In addition, an increased Ishak score ≥4 reduced the survival time with the native liver (hazard ratio 6.6 [95% CI 1.9-23.3]).

CONCLUSIONS

The Ishak score was revealed to have the best interobserver variability as well as prognostic validity towards an early liver transplantation in BA patients. Due to its easy applicability, the Ishak score was proven superior in comparison to the Chevallier score and ABAA. Therefore, use of the Ishak score is recommended in daily clinical routine for analyzing liver biopsies in BA patients.

The Inducible Response of the Nematode Caenorhabditis elegans to Members of Its Natural Microbiota Across Development and Adult Life

The biology of all organisms is influenced by the associated community of microorganisms. In spite of its importance, it is usually not well understood how exactly this microbiota affects host functions and what are the underlying molecular processes. To rectify this knowledge gap, we took advantage of the nematode Caenorhabditis elegans as a tractable, experimental model system and assessed the inducible transcriptome response after colonization with members of its native microbiota. For this study, we focused on two isolates of the genus Ochrobactrum. These bacteria are known to be abundant in the nematode’s microbiota and are capable of colonizing and persisting in the nematode gut, even under stressful conditions. The transcriptome response was assessed across development and three time points of adult life, using general and C. elegans-specific enrichment analyses to identify affected functions. Our assessment revealed an influence of the microbiota members on the nematode’s dietary response, development, fertility, immunity, and energy metabolism. This response is mainly regulated by a GATA transcription factor, most likely ELT-2, as indicated by the enrichment of (i) the GATA motif in the promoter regions of inducible genes and (ii) of ELT-2 targets among the differentially expressed genes. We compared our transcriptome results with a corresponding previously characterized proteome data set, highlighting a significant overlap in the differentially expressed genes, the affected functions, and ELT-2 target genes. Our analysis further identified a core set of 86 genes that consistently responded to the microbiota members across development and adult life, including several C-type lectin-like genes and genes known to be involved in energy metabolism or fertility. We additionally assessed the consequences of induced gene expression with the help of metabolic network model analysis, using a previously established metabolic network for C. elegans. This analysis complemented the enrichment analyses by revealing an influence of the Ochrobactrum isolates on C. elegans energy metabolism and furthermore metabolism of specific amino acids, fatty acids, and also folate biosynthesis. Our findings highlight the multifaceted impact of naturally colonizing microbiota isolates on C. elegans life history and thereby provide a framework for further analysis of microbiota-mediated host functions.

A multi-parent recombinant inbred line population of C. elegans allows identification of novel QTLs for complex life history traits

BACKGROUND

The nematode Caenorhabditis elegans has been extensively used to explore the relationships between complex traits, genotypes, and environments. Complex traits can vary across different genotypes of a species, and the genetic regulators of trait variation can be mapped on the genome using quantitative trait locus (QTL) analysis of recombinant inbred lines (RILs) derived from genetically and phenotypically divergent parents. Most RILs have been derived from crossing two parents from globally distant locations. However, the genetic diversity between local C. elegans populations can be as diverse as between global populations and could thus provide means of identifying genetic variation associated with complex traits relevant on a broader scale.

RESULTS

To investigate the effect of local genetic variation on heritable traits, we developed a new RIL population derived from 4 parental wild isolates collected from 2 closely located sites in France: Orsay and Santeuil. We crossed these 4 genetically diverse parental isolates to generate a population of 200 multi-parental RILs and used RNA-seq to obtain sequence polymorphisms identifying almost 9000 SNPs variable between the 4 genotypes with an average spacing of 11 kb, doubling the mapping resolution relative to currently available RIL panels for many loci. The SNPs were used to construct a genetic map to facilitate QTL analysis. We measured life history traits such as lifespan, stress resistance, developmental speed, and population growth in different environments, and found substantial variation for most traits. We detected multiple QTLs for most traits, including novel QTLs not found in previous QTL analysis, including those for lifespan and pathogen responses. This shows that recombining genetic variation across C. elegans populations that are in geographical close proximity provides ample variation for QTL mapping.

CONCLUSION

Taken together, we show that using more parents than the classical two parental genotypes to construct a RIL population facilitates the detection of QTLs and that the use of wild isolates facilitates the detection of QTLs. The use of multi-parent RIL populations can further enhance our understanding of local adaptation and life history trade-offs.

The impact of local control on overall survival after stereotactic body radiotherapy for liver and lung metastases from colorectal cancer: a combined analysis of 388 patients with 500 metastases

BACKGROUND

The aim of this analysis was to model the effect of local control (LC) on overall survival (OS) in patients treated with stereotactic body radiotherapy (SBRT) for liver or lung metastases from colorectal cancer.

METHODS

The analysis is based on pooled data from two retrospective SBRT databases for pulmonary and hepatic metastases from 27 centers from Germany and Switzerland. Only patients with metastases from colorectal cancer were considered to avoid histology as a confounding factor. An illness-death model was employed to model the relationship between LC and OS.

RESULTS

Three hundred eighty-eight patients with 500 metastatic lesions (lung n = 209, liver n = 291) were included and analyzed. Median follow-up time for local recurrence assessment was 12.1 months. Ninety-nine patients with 112 lesions experienced local failure. Seventy-one of these patients died after local failure. Median survival time was 27.9 months in all patients and 25.4 months versus 30.6 months in patients with and without local failure after SBRT. The baseline risk of death after local failure exceeds the baseline risk of death without local failure at 10 months indicating better survival with LC.

CONCLUSION

In CRC patients with lung or liver metastases, our findings suggest improved long-term OS by achieving metastatic disease control using SBRT in patients with a projected OS estimate of > 12 months.

Injuries, dislocations, and poor health perceived by older adults to result from vigorous physical activity: implications for active living, health promotion, and gerontology

This study examines older adults' perceptions about their participation in vigorous physical activity (VPA) and the association between VPA and self-related health. A total of 686 older adults responded to self-reported questionnaires, and Pearson's ꭓ2 test and binary logistic regression were used to present findings. About 74% of older adults reported experiencing dislocations, fractures, or/and other forms of injury in intense physical activities lasting 30 minutes or more a day. After controlling for relevant socio-demographic factors, older adults who participated in VPA for 30 or more minutes a day were less likely (OR=0,129; p=0,000) to report good health compared with those who participated in VPA for less than 30 minutes. It is concluded that VPA in older populations can result in casualties that may compel older adults to underrate their health, which can discourage active living habits in older populations and discredit PA/health promotion programs.

The association between social capital factors and sedentary behaviour among older adults: Does the built environment matter?

Evidences in the literature uphold social capital factors, namely social networks and support as a buffer against sedentary behaviour. A recent school of thought also contends that the built environment supports these factors to reduce sedentary behaviour. This study examined the role of the built environment in the association between the said social capital factors and sedentary behaviour. Participants of the study were 504 volunteer older adults in Accra, Ghana. A self-reported questionnaire was used to gather data, and structural equation modelling was used to present findings through Amos. The structural model through which the associations were tested produced a good fit (χ2=231,32; p=0,198). The study confirmed that the built factors are directly and indirectly (via social capital factors) associated with sedentary behaviour. «Road structure and safety» and «health and paramedical services» directly reduced sedentary behaviour, while «public security services» was positively associated with sedentary behaviour. All the built environmental factors, except «care and recreational homes», influenced sedentary behaviour through the social capital factors. We conclude that built environmental factors reinforce social capital to reduce sedentary behaviour, but this support may also increase sedentary time if the built environment is not well structured.

[Biliary atresia and congenital cholestatic syndromes : Characteristics before, after and during transition]

BACKGROUND

A growing number of patients with biliary atresia and congenital cholestatic syndromes are reaching adulthood. These patients often have a number of typical medical features, including specific characteristics of liver transplantation medicine.

OBJECTIVE

What are the special features in the care of adults suffering from liver diseases with manifestation in childhood and adolescence, both before and after liver transplantation (LTX). How does the progression of individual diseases differ depending on age at manifestation? What are specific aspects following pediatric LTX?

PATIENTS AND METHODS

Evaluation and discussion of existing guidelines and recommendations of the individual disciplines and professional societies as well as the current literature. Joint discussion of the recommendations between disciplines (gastroenterology, pediatric gastroenterology, surgery). Inclusion of center-specific experiences with transition from existing transition outpatient departments and training.

RESULTS

The recommendations are presented specifically for each disease. Special features in individual diseases after LTX are also discussed. Diagnosis-independent general treatment concepts for cholestasis and chronic liver disease are presented.

CONCLUSION

Patients with biliary atresia and congenital cholestatic syndromes have a life-long chronic liver disease with and without LTX and require specific medical care. The patients benefit from the pooling of expertise in the individual disciplines.

Spermatogonial quantity in human prepubertal testicular tissue collected for fertility preservation prior to potentially sterilizing therapy

STUDY QUESTION

Does chemotherapy exposure (with or without alkylating agents) or primary diagnosis affect spermatogonial quantity in human prepubertal testicular tissue?

SUMMARY ANSWER

Spermatogonial quantity is significantly reduced in testes of prepubertal boys treated with alkylating agent therapies or with hydroxyurea for sickle cell disease.

WHAT IS KNOWN ALREADY

Cryopreservation of spermatogonial stem cells, followed by transplantation into the testis after treatment, is a proposed clinical option for fertility restoration in children. The key clinical consideration behind this approach is a sufficient quantity of healthy cryopreserved spermatogonia. However, since most boys with malignancies start therapy with agents that are not potentially sterilizing, they will have already received some chemotherapy before testicular tissue cryopreservation is considered.

STUDY DESIGN, SIZE, DURATION

We examined histological sections of prepubertal testicular tissue to elucidate whether chemotherapy exposure or primary diagnosis affects spermatogonial quantity. Quantity of spermatogonia per transverse tubular cross-section (S/T) was assessed in relation to treatment characteristics and normative reference values in histological sections of paraffin embedded testicular tissue samples collected from 32 consecutive boy patients (aged 6.3 ± 3.8 [mean ± SD] years) between 2014 and 2017, as part of the NORDFERTIL study, and in 14 control samples (from boys aged 5.6 ± 5.0 [mean ± SD] years) from an internal biobank.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Prepubertal boys in Sweden, Finland and Iceland who were facing treatments associated with a very high risk of infertility, were offered the experimental procedure of testicular cryopreservation. Exclusion criteria were testicular volumes >10 ml and high bleeding or infection risk. There were 18 patients with a diagnosis of malignancy and 14 patients a non-malignant diagnosis. While 20 patients had the testicular biopsy performed 1-45 days after chemotherapy, 12 patients had not received any chemotherapy. In addition, 14 testicular tissue samples of patients with no reported testicular pathology, obtained from the internal biobank of the Department of Pathology at Karolinska University Hospital, were included as control samples in addition to reference values obtained from a recently published meta-analysis. The quantity of spermatogonia was assessed by both morphological and immunohistochemical analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

The main finding was a significant reduction in spermatogonial cell counts in boys treated with alkylating agents or with hydroxyurea for sickle cell disease. The mean S/T values in boys exposed to alkylating agents (0.2 ± 0.3, n = 6) or in boys with sickle cell disease and exposed to hydroxyurea (0.3 ± 0.6, n = 6) were significantly lower (P = 0.003 and P = 0.008, respectively) than in a group exposed to non-alkylating agents or in biobank control samples (1.7 ± 1.0, n = 8 and 4.1 ± 4.6, n = 14, respectively). The mean S/T values of the testicular tissue samples included in the biobank control group and the patient group exposed to non-alkylating agents were within recently published normative reference values.

LIMITATIONS, REASONS FOR CAUTION

Normal testicular tissue samples included in this study were obtained from the internal biobank of Karolinska University Hospital. Samples were considered normal and included in the study if no testicular pathology was reported in the analysed samples. However, detailed information regarding previous medical treatments and testicular volumes of patients included in this biobank were not available.

WIDER IMPLICATIONS OF THE FINDINGS

This study summarizes, for the first time, spermatogonial quantity in a prepubertal patient cohort just before and after potentially sterilizing treatments. Boys facing cancer and cytotoxic therapies are regarded as the major group who will benefit from novel fertility preservation techniques. There are no previous reports correlating spermatogonial quantity to cumulative exposure to alkylating agents and anthracyclines (non-alkylating agents) and no information about the timing of cytotoxic exposures among this particular patient cohort. For prepubertal boys in whom fertility preservation is indicated, testicular tissue should be obtained before initiation of chemotherapy with alkylating agents, whilst for those with sickle cell disease and treated with hydroxyurea, this approach to fertility preservation may not be feasible.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from The Swedish Childhood Cancer Foundation (PR2016-0124; TJ2016-0093; PR2015-0073, TJ2015-0046) (J.-B.S. and K.J.), the Jane and Dan Olssons Foundation (2016-33) (J.-B.S.), the Finnish Cancer Society (K.J.), the Foundation for Paediatric Research (J.-B.S.), Kronprinsessan Lovisas Förening För Barnasjukvård/ Stiftelsen Axel Tielmans Minnesfond, Samariten Foundation (J.-B.S.), the Väre Foundation for Paediatric Cancer Research (K.J.) and the Swedish Research Council (2012-6352) (O.S.). R.T.M. was supported by a Wellcome Trust Fellowship (09822). J.P.A.-L. and M.K. were supported by the ITN Marie Curie program 'Growsperm' (EU-FP7-PEOPLE-2013-ITN 603568). The authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Perioperative hyperoxia and post-operative cardiac complications in adults undergoing non-cardiac surgery: Systematic review protocol

BACKGROUND

Oxygen therapy is used liberally for all patients undergoing anaesthesia. Recent studies have raised concerns that it may not be without complications when arterial oxygen concentrations reach supranormal concentrations (hyperoxia). Studies of oxygen therapy have raised concerns that the risk of myocardial injury and infarction is elevated in patients with hyperoxia due to vasoconstriction and formation of reactive oxygen species. Due to lack of symptoms or silent ischaemia, post-operative myocardial injury may be missed clinically. In some studies, perioperative hyperoxia has been linked to increased long-term mortality, but cardiac complications are sparsely evaluated. The aim of this review is to summarize current evidence to assess the risk and benefits of perioperative hyperoxia on post-operative cardiac complications.

METHODS

This systematic review will include meta-analyses and Trial Sequential Analyses. We will include randomized clinical trials with patients undergoing non-cardiac surgery if the allocation separates patients into a target of either higher (above 0.60) or lower (below 0.40) inspired oxygen fraction. To minimize the risk of systematic error, we will assess the risk of bias of the included trials using the Cochrane Risk of Bias Tool. The overall quality of evidence for each outcome will be assessed with the Grading of Recommendation, Assessment, Development and Evaluation (GRADE).

DISCUSSION

This systematic review will provide data on a severe, albeit rare, potential risk of oxygen therapy. We will do a trial sequential analysis to assess the robustness of results as well as help estimate the required patient size for future clinical trials.

Socioeconomic status and quality of life in patients with locally advanced head and neck cancer

PURPOSE

Socioeconomic aspects play an important role in health care. Patients with locally advanced head and neck cancer (LAHNC) experience detrimental effects on their quality of life (QoL). This prospective study examines QoL differences between patients with different socioeconomic status (SES) after intensity-modulated radiation therapy (IMRT).

PATIENTS AND METHODS

In all, 161 patients were questioned at the end of IMRT and at 12 and 24 months follow-up using the questionnaires of the European Organization for Research and Treatment of Cancer (EORTC) QLQ-30 and QLQ-HN35. Patients' QoL 2 years after IMRT was compared to a population reference sample and QoL of patients from lower, middle, and higher social class 2 years after IMRT was analyzed by ANCOVA using baseline QoL (end of radiation treatment) as a covariate.

RESULTS

Patients with high SES report worse QoL at the end of IMRT in the domains global health status (-15.2; p = 0.005), role function (-23.8; p = 0.002), and social function (-19.4; p = 0.023) compared to patients with middle and low SES. QoL improved during the first 12 and 24 months. However, 2 years after IMRT, middle and low SES patients report lower QoL in the domains global health status, physical function, and role function, and report a higher general (fatigue, pain, dyspnea) and head and neck cancer-specific symptom burden (pain, swallowing, senses, speech, social eating, opening mouth, and felt ill) than patients with high SES.

CONCLUSION

After IMRT for LAHNC, patients with high SES report worse QoL compared to patients with middle or low SES. There is a marked improvement within the first 24 months in many domains. However, the magnitude of improvement in patients with middle or low SES is significantly smaller compared to patients with high SES.