The role of adipose tissue and subsequent liver tissue hypoxia in obesity and early stage metabolic dysfunction associated steatotic liver disease.

BACKGROUND: Obesity is linked to several health complication, including Metabolic Dysfunction Associated Steatotic Liver Disease (MASLD). Adipose tissue hypoxia has been suggested as an important player in the pathophysiological mechanism leading to chronic inflammation in obesity, and in the progression of MASLD. The study aims to investigate the effect of progressive obesity on adipose and liver tissue hypoxia. METHODS: Male 8-week-old C57BL/6J mice were fed a high-fat high-fructose diet (HFHFD) or control diet (CD) for 4, 8, 12, 16 and 20 weeks. Serum ALT, AST and lipid levels were determined, and glucose and insulin tolerance testing was performed. Liver, gonadal and subcutaneous adipose tissue was assessed histologically. In vivo tissue pO2 measurements were performed in gonadal adipose tissue and liver under anesthesia. A PCR array for hypoxia responsive genes was performed in liver and adipose tissue. The main findings in the liver were validated in another diet-induced MASLD mice model, the choline-deficient L-amino acid defined high-fat diet (CDAHFD). RESULTS: HFHFD feeding induced a progressive obesity, dyslipidaemia, insulin resistance and MASLD. In vivo pO2 was decreased in gonadal adipose tissue after 8 weeks of HFHFD compared to CD, and decreased further until 20 weeks. Liver pO2 was only significantly decreased after 16 and 20 weeks of HFHFD. Gene expression and histology confirmed the presence of hypoxia in liver and adipose tissue. Hypoxia could not be confirmed in mice fed a CDAHFD. CONCLUSION: Diet-induced obesity in mice is associated with hypoxia in liver and adipose tissue. Adipose tissue hypoxia develops early in obesity, while liver hypoxia occurs later in the obesity development but still within the early stages of MASLD. Liver hypoxia could not be directly confirmed in a non-obese liver-only MASLD mice model, indicating that obesity-related processes such as adipose tissue hypoxia are important in the pathophysiology of obesity and MASLD.

Humoral immunity to SARS-CoV-2 in kidney transplant recipients and dialysis patients: IgA and IgG patterns unraveled after SARS-CoV-2 infection and vaccination.

BACKGROUND: Infection with SARS-CoV-2 in high-risk groups such as kidney transplant and dialysis patients is shown to be associated with a more serious course of the disease. Four years after the start of the COVID-19 pandemic, crucial knowledge on the immune responses in these patient groups is still lacking. Therefore, this study aimed at investigating the humoral immune response after a SARS-CoV-2 infection compared to vaccination as well as the evolution of immunoglobulins over time. METHODS: Kidney transplant recipients, patients on haemodialysis or on peritoneal dialysis and healthy controls were included in this longitudinal multicenter study. SARS-CoV-2 anti-RBD, anti-NP and anti-S1S2 immunoglobulin G (IgG) and A (IgA) as well as the neutralizing antibody capacity were measured. RESULTS: Kidney transplant recipients had a significantly better humoral response to SARS-CoV-2 after infection (86.4%) than after a two-dose mRNA vaccination (55.8%) while seroconversion was comparable in patients on haemodialysis after infection (95.8%) versus vaccination (89.4%). In individuals without prior COVID-19, the IgG levels after vaccination were significantly lower in kidney transplant recipients when compared to all other groups. However, the IgA titres remained the highest in this patient group at each time point, both after infection and vaccination. A history COVID-19 was associated with higher antibody levels after double-dose vaccination in all patient categories and, while decreasing, titres remained high six months after double-dose vaccination. CONCLUSION: Kidney transplant recipients had a more robust humoral response to SARS-CoV-2 following infection compared to a two-dose mRNA vaccination, while patients on haemodialysis exhibited comparable seroconversion rates. Notably, individuals with prior COVID-19 exhibited higher IgG levels in response to vaccination. Hybrid immunity is thus the best possible defence against severe COVID-19 disease and seems also to hold up for these populations. Next, it is not clear whether the higher IgA levels in the kidney transplant recipients is beneficial for neutralizing SARS-CoV-2 or if it is a sign of disease severity.

Single-day and multi-day exposure to orogastric gavages does not affect intestinal barrier function in mice.

Animals involved in common laboratory procedures experience minor levels of stress. The direct effect of limited amounts of stress on gastrointestinal function has not been reported yet. Therefore, this study aimed to assess the effect of single-day and multi-day orogastric gavages on gut physiology in mice. To this end, 12-wk-old female C57Bl6/J mice were randomized to receive treatment with sterile water (200 µL) delivered by orogastric gavages twice daily for a total of 1 or 10 day(s). Control animals did not receive any treatment. Subsequently, gastrointestinal function was assessed by measuring fecal pellet production. Furthermore, ex vivo intestinal barrier and secretory function of the distal colon, proximal colon, and terminal ileum were quantified in Ussing chambers. In mice, single-day gavages did neither influence corticosterone levels nor gastrointestinal function. In mice exposed to multi-day gavages, corticosterone levels were slightly but significantly increased compared with controls after 10 days of treatment. Gastrointestinal motor function was altered, as evidenced by increased fecal pellet counts and a small increase in fecal water content. However, exposure to repeated gavages did not lead to detectable alterations in gastrointestinal barrier function as quantified by the paracellular flux of the probe 4 kDa FITC-dextran as well as transepithelial resistance measurements. Thus, the administration of drugs via single-day or multi-day orogastric gavages leads to no or minor stress in mice, respectively. In both cases, it does not hamper the study of the intestinal barrier function and therefore remains a valuable administration route in preclinical pharmacological research.NEW & NOTEWORTHY Exposure of mice to serial orogastric gavages over the course of 10 days leads to a small but significant increase in plasma corticosterone levels, indicating the presence of a limited amount of stress that is absent after a single-day treatment. This minor stress after multi-day gavages results in increased fecal pellet production and fecal water content in exposed compared with nontreated mice but does not affect the intestinal barrier function in the distal colon, proximal colon, or terminal ileum.

How can peer teaching influence the development of medical students? a descriptive, longitudinal interview study.

BACKGROUND: Peer-assisted learning (PAL) - where students take up a teaching role at an early stage of their training-is widely used in medical curricula. Many qualitative studies have investigated the perceptions and benefits of PAL, but no studies have longitudinally explored how peer teachers experienced their development. This could allow for a better understanding of PAL. In this study, we explored the perceived impact of being a peer teacher on the development of personal and professional competencies as a medical student. METHODS: We longitudinally conducted semi-structured interviews with peer teachers, during their 2-year teaching period in the skills lab at the University of Antwerp and applied descriptive thematic analysis. RESULTS: In total we gathered 47 interviews in 13 peer teachers (9 female, 4 male,. 1-7 interviews each). Peer teachers reported an increase in self-confidence, which gradually transformed into self-efficacy in clinical and teaching skills., Participants told us to be inspired by the previous generation of peer teachers. Their motivation shifted from personal benefits to benefiting others while becoming a role model themselves. The peer teachers illustrated how they developed maturity by integrating different CanMEDS roles. They grew in reflection, changed/transformed an initial mark-driven study drive into more patient-centered ambitions, and started developing a personal style. CONCLUSIONS: Our study suggests that being a peer teacher leads to more self-efficacy, in clinical and teaching skills, to become a role model with as motivation to benefit others and to grow towards a good doctor maturity. Although the task is to teach peers, this opportunity nurtures the practice and integration of various CanMEDS roles, not only that of scholar but also communicator, collaborator and leader, thereby positively influencing their personal and professional development and their identity as a doctor (professional role).

Seroconversion rate after primary vaccination with two doses of BNT162b2 versus mRNA-1273 in solid organ transplant recipients: a systematic review and meta-analysis.

BACKGROUND: In the general population, the seroconversion rate after primary vaccination with two doses of an anti-severe acute respiratory syndrome coronavirus 2 messenger RNA (mRNA) vaccine reaches nearly 100%, with significantly higher antibody titers after mRNA-1273 vaccination compared to BNT162b2 vaccination. Here we performed a systematic review and meta-analysis to compare the antibody response after two-dose mRNA-1273 versus BNT162b2 vaccination in solid organ transplant (SOT) recipients. METHODS: A systematic literature review was performed using PubMed, Web of Science and the Cochrane Library and original research papers were included for a meta-analysis to calculate vaccine-specific seroconversion rates for each of the mRNA vaccines. Next, the pooled relative seroconversion rate was estimated. RESULTS: Eight studies that described the development of antibodies against receptor-binding domain (RBD) and/or spike protein were eligible for meta-analysis. Two of these studies also reported antibody titers. The meta-analysis revealed lower seroconversion rates in SOT recipients vaccinated with two doses of BNT162b2 {44.3% [95% confidence interval (CI) 34.1-54.7]} as compared with patients vaccinated with two doses of mRNA-1273 [58.4% (95% CI 47.2-69.2)]. The relative seroconversion rate was 0.795 (95% CI 0.732-0.864). CONCLUSIONS: This systematic review and meta-analysis indicates that in SOT recipients, higher seroconversion rates were observed after vaccination with mRNA-1273 compared with BNT162b2.

Does peer teaching improve academic results and competencies during medical school? A mixed methods study.

BACKGROUND: This study investigates the impact of Peer-Assisted Learning (PAL) in clinical skills on peer teachers' academic scores and competencies; however, controversy remains on this topic, and concrete evidence on its impact lacking. METHODS: We performed a mixed methods study combining a retrospective cohort study with a modified Delphi survey. Peer teachers and Skills Lab faculty members participated in this study. A validated questionnaire, the CanMEDS Competency Based Inventory (CCBI), and group interviews were used to assess the outcomes of PAL. Our results were also triangulated with literature data. RESULTS: In 3 consecutive cohorts of medical students (n = 311), 78 participated in PAL. Peer teachers obtained higher scores from the start of the study, at different timepoints in medical school, and on their final scores compared to all other students. Interestingly their progress followed the same path and magnitude as other well-performing students. However, based on our findings from a modified Delphi survey (CCBI interviews) and a literature review, we found further supporting evidence for a positive impact of PAL on the competencies of physical skills (medical expert), teamwork and leadership (collaborator), lifelong learning (scholar), and for admitting uncertainty/limits (professional) within the CanMEDS roles. CONCLUSIONS: We conclude that higher achieving students are more likely to volunteer for a peer tutoring program; however this does not significantly augment their academic scores as compared to above well-performing non-teaching fellow students. Importantly, our modified Delphi survey indicated which CanMEDS roles were positively impacted by PAL: medical expert, collaborator, scholar and professional.

Functional respiratory imaging provides novel insights into the long-term respiratory sequelae of bronchopulmonary dysplasia.

RATIONALE: Bronchopulmonary dysplasia (BPD) is a common complication of preterm birth. Lung function and imaging are classically used to assess BPD. Functional respiratory imaging (FRI) combines a structural and functional assessment of the airways and their vasculature. We aimed to assess BPD using FRI and to correlate these findings with the clinical presentation. METHODS: We included 37 adolescents with a history of preterm birth (22 BPD cases and 15 preterm controls). The study protocol included a detailed history, lung function testing and computed tomography (CT) (at total lung capacity (TLC) and functional residual capacity (FRC)) with FRI. CT images were also assessed using the Aukland scoring system. RESULTS: BPD patients had lower forced expiratory volume in 1 s to forced vital capacity ratio (p=0.02) and impaired diffusion capacity (p=0.02). Aukland CT scores were not different between the two groups. FRI analysis showed higher lobar volumes in BPD patients at FRC (p<0.01), but not at TLC. Airway resistance was significantly higher in the BPD group, especially in the distal airways. Additionally, FRI showed more air trapping in BPD patients, in contrast to findings on conventional CT images. CONCLUSION: This study is the first to use FRI in research for BPD. FRI analysis showed higher lobar volumes in BPD patients, indicating air trapping and reduced inspiratory capacity. In contrast to Aukland CT scores, FRI showed more air trapping in the BPD group, suggesting that FRI might be a more sensitive detection method. Importantly, we also showed increased distal airway resistance in BPD patients. By combining structural and functional assessment, FRI may help to better understand the long-term sequelae of BPD.

Body composition monitoring in children and adolescents: reproducibility and reference values.

There is an increasing need for suitable tools to evaluate body composition in paediatrics. The Body Composition Monitor (BCM) shows promise as a method, but reference values in children are lacking. Twenty children were included and measured twice by 4 different raters to asses inter- and intra-rater reproducibility of the BCM. Reliability was assessed using the Bland-Altman method and by calculating intraclass correlation coefficients (ICCs). The intra-rater ICCs were high (≥ 0.97) for all parameters measured by BCM as were the inter-rater ICCs for all parameters (≥ 0.98) except for overhydration (0.76). Consequently, a study was set up in which BCM measurements were performed in 2058 healthy children aged 3-18.5 years. The age- and gender-specific percentile values and reference curves for body composition (BMI, waist circumference, fat mass and lean tissue mass) and fluid status (extracellular and intracellular water and total body water) relative to age were produced using the GAMLSS method for growth curves.Conclusion: A high reproducibility of BCM measurements was found for fat mass, lean tissue mass, extracellular water and total body water. Reference values for these BCM parameters were calculated in over 2000 children and adolescents aged 3 to 18 years. What is Known • The 4-compartment model is regarded as the 'gold standard' of body composition methods, but is inappropriate for regular follow-up or screening of large groups, because of associated limitations. • Body Composition Monitor® is an inexpensive field method that has the potential to be an adequate monitoring tool. What is New • Good reproducibility of BCM measurements in children provides evidence to use the device in longitudinal follow-up, multicentre and comparative studies. • Paediatric reference values relative to age and sex for the various compartments of the body are provided.

Improving Self-Reflection Assessment Practices: Comparative Judgment as an Alternative to Rubrics.

CONSTRUCT: The authors aimed to investigate the utility of the comparative judgment method for assessing students' written self-reflections. BACKGROUND: Medical practitioners' reflective skills are increasingly considered important and therefore included in the medical education curriculum. However, assessing students' reflective skills using rubrics does not appear to guarantee adequate inter-rater reliabilities. Recently, comparative judgment was introduced as a new method to evaluate performance assessments. This study investigates the merits and limitations of the comparative judgment method for assessing students' written self-reflections. More specifically, it examines the reliability in relation to the time spent assessing, the correlation between the scores obtained using the two methods (rubrics and comparative judgment), and, raters' perceptions of the comparative judgment method. APPROACH: Twenty-two self-reflections, that had previously been scored using a rubric, were assessed by a group of eight raters using comparative judgment. Two hundred comparisons were completed and a rank order was calculated. Raters' impressions were investigated using a focus group. FINDINGS: Using comparative judgment, each self-reflection needed to be compared seven times with another self-reflection to reach a scale separation reliability of .55. The inter-rater reliability of rating (ICC, (1, k)) using rubrics was .56. The time investment required for these reliability levels in both methods was around 24 minutes. The Kendall's tau rank correlation indicated a strong correlation between the scores obtained via both methods. Raters reported that making comparisons made them evaluate the quality of self-reflections in a more nuanced way. Time investment was, however, considered heavy, especially for the first comparisons. Although raters appreciated that they did not have to assign a grade to each self-reflection, the fact that the method does not automatically lead to a grade or feedback was considered a downside. CONCLUSIONS: First evidence was provided for the comparative judgment method as an alternative to using rubrics for assessing students' written self-reflections. Before comparative judgment can be implemented for summative assessment, more research is needed on the time investment required to ensure no contradictory feedback is given back to students. Moreover, as the comparative judgment method requires an additional standard setting exercise to obtain grades, more research is warranted on the merits and limitations of this method when a pass/fail approach is used.

Proteolytic Cleavage of Bioactive Peptides and Protease-Activated Receptors in Acute and Post-Colitis.

The protease activity in inflammatory bowel disease (IBD) and irritable bowel syndrome has been studied extensively using synthetic fluorogenic substrates targeting specific sets of proteases. We explored activities in colonic tissue from a 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis rat model by investigating the cleavage of bioactive peptides. Pure trypsin- and elastase-like proteases on the one hand and colonic tissue from rats with TNBS-induced colitis in the acute or post-inflammatory phase on the other, were incubated with relevant peptides to identify their cleavage pattern by mass spectrometry. An increased cleavage of several peptides was observed in the colon from acute colitis rats. The tethered ligand (TL) sequences of peptides mimicking the N-terminus of protease-activated receptors (PAR) 1 and 4 were significantly unmasked by acute colitis samples and these cleavages were positively correlated with thrombin activity. Increased cleavage of ß-endorphin and disarming of the TL-sequence of the PAR3-based peptide were observed in acute colitis and linked to chymotrypsin-like activity. Increased processing of the enkephalins points to the involvement of proteases with specificities different from trypsin- or chymotrypsin-like enzymes. In conclusion, our results suggest thrombin, chymotrypsin-like proteases and a set of proteases with different specificities as potential therapeutic targets in IBD.

The use of plasma donor-derived, cell-free DNA to monitor acute rejection after kidney transplantation.

BACKGROUND: After transplantation, cell-free deoxyribonucleic acid (DNA) derived from the donor organ (ddcfDNA) can be detected in the recipient's circulation. We aimed to investigate the role of plasma ddcfDNA as biomarker for acute kidney rejection. METHODS: From 107 kidney transplant recipients, plasma samples were collected longitudinally after transplantation (Day 1 to 3 months) within a multicentre set-up. Cell-free DNA from the donor was quantified in plasma as a fraction of the total cell-free DNA by next generation sequencing using a targeted, multiplex polymerase chain reaction-based method for the analysis of single nucleotide polymorphisms. RESULTS: Increases of the ddcfDNA% above a threshold value of 0.88% were significantly associated with the occurrence of episodes of acute rejection (P = 0.017), acute tubular necrosis (P = 0.011) and acute pyelonephritis (P = 0.032). A receiver operating characteristic curve analysis revealed an equal area under the curve of the ddcfDNA% and serum creatinine of 0.64 for the diagnosis of acute rejection. CONCLUSIONS: Although increases in plasma ddcfDNA% are associated with graft injury, plasma ddcfDNA does not outperform the diagnostic capacity of the serum creatinine in the diagnosis of acute rejection.

Donor-derived cell-free DNA as a biomarker for rejection after kidney transplantation: a systematic review and meta-analysis.

A systematic review and meta-analysis were performed to investigate the value of donor-derived cell-free DNA (dd-cfDNA) as a noninvasive biomarker in diagnosing kidney allograft rejection. We searched PubMed, Web of Science and the Cochrane Library for original research papers published between January 1994 and May 2020 on dd-cfDNA fractions in blood of kidney allograft recipients. A single-group meta-analysis was performed by computing pooled estimates for dd-cfDNA fractions using the weighted median of medians or quantile estimation (QE) approach. Weighted median differences in medians (WMDMs) and median differences based on the QE method were used for pairwise comparisons. Despite heterogeneity among the selected studies, the meta-analysis revealed significantly higher median dd-cfDNA fractions in patients with antibody-mediated rejection (ABMR) than patients without rejection or patients with stable graft function. When comparing patients with T cell-mediated rejection (TCMR) and patients with ABMR, our two statistical approaches revealed conflicting results. Patients with TCMR did not have different median dd-cfDNA fractions than patients without rejection or patients with stable graft function. dd-cfDNA may be a useful marker for ABMR, but probably not for TCMR.

Clinical- and surgery-specific risk factors for post-operative sepsis: a systematic review and meta-analysis of over 30 million patients.

Post-operative sepsis is a severe complication of surgery, which often worsens the clinical outcomes. While several risk factors have been identified, the importance of others remains uncertain. This systematic review and meta-analysis aimed to determine patient and surgery-related risk factors for post-operative sepsis. We reviewed Medline, the Web of Science, and the Cochrane library, systematically, for articles describing risk factors for sepsis. The role of eligible risk factors was investigated using a random-effects model, while analyzing univariate and multivariate data separately. Among 193 pro- and retrospective articles, comprising over 30 million patients, 38 eligible risk factors were selected for this meta-analysis. The patient-related risk factors associated with post-operative sepsis included male gender (odds ratio, OR 1.41), pre-existing heart failure (OR 2.53), diabetes (OR 1.41), and chronic kidney disease (OR 1.26). The surgery-related risk factors identified included emergency surgery (OR 3.38), peri-operative blood transfusion (OR 1.90), inpatient hospital stay (OR 2.31), and open surgery (OR 1.80). The adjusted overall incidence of surgical sepsis was 1.84%. In conclusion, multiple-patient and surgery-related risk factors are associated with the development of post-operative sepsis. Recognizing these risk factors could assist in the pre-operative identification of patients at risk of post-operative sepsis.

Severe steatosis induces portal hypertension by systemic arterial hyporeactivity and hepatic vasoconstrictor hyperreactivity in rats.

Non-alcoholic fatty liver disease (NAFLD) has become the most prevalent chronic liver disease. The presence of portal hypertension has been demonstrated in NAFLD prior to development of inflammation or fibrosis, and is a result of extrahepatic and intrahepatic factors, principally driven by vascular dysfunction. An increased intrahepatic vascular resistance potentially contributes to progression of NAFLD via intralobular hypoxia. However, the exact mechanisms underlying vascular dysfunction in NAFLD remain unknown. This study investigates systemic hemodynamics and both aortic and intrahepatic vascular reactivity in a rat model of severe steatosis. Wistar rats were fed a methionine-choline-deficient diet, inducing steatosis, or control diet for 4 weeks. In vivo hemodynamic measurements, aortic contractility studies, and in situ liver perfusion experiments were performed. The mean arterial blood pressure was lower and portal blood pressure was higher in steatosis compared to controls. The maximal contraction force in aortic rings from steatotic rats was markedly reduced compared to controls. While blockade of nitric oxide (NO) production did not reveal any differences, cyclooxygenase (COX) blockade reduced aortic reactivity in both controls and steatosis, whereas effects were more pronounced in controls. Effects could be attributed to COX-2 iso-enzyme activity. In in situ liver perfusion experiments, exogenous NO donation or endogenous NO stimulation reduced the transhepatic pressure gradient (THPG), whereas NO synthase blockade increased the THPG only in steatosis, but not in controls. Alpha-1-adrenergic stimulation and endothelin-1 induced a significantly more pronounced increase in THPG in steatosis compared to controls. Our results demonstrate that severe steatosis, without inflammation or fibrosis, induces portal hypertension and signs of a hyperdynamic circulation, accompanied by extrahepatic arterial hyporeactivity and intrahepatic vascular hyperreactivity. The arterial hyporeactivity seems to be NO-independent, but appears to be mediated by specific COX-2-related mechanisms. Besides, the increased intrahepatic vascular resistance in steatosis appears not to be NO-related but rather to vasoconstrictor hyperreactivity.

Failed Downregulation of Circulating MicroRNA-155 in the Early Phase after ST Elevation Myocardial Infarction Is Associated with Adverse Left Ventricular Remodeling.

BACKGROUND: MicroRNA are noncoding RNA that have a significant role in both inflammatory and cardiovascular diseases. AIMS: We aimed to assess whether the inflammation-related microRNA-155 is associated with the development of adverse left ventricular (LV) remodeling following ST elevation myocardial infarction (STEMI). METHODS: Peripheral blood samples were collected in the inflammatory (day 2), proliferative (day 5), and maturation phases (6 months) after STEMI (n = 20). Granulocytes, monocytes, and lymphocytes were enumerated with flow cytometry. The changes in LV volumes were assessed with 3-D echocardiography on day 1 and after 6 months. Adverse remodeling was defined as a >20% increase in end-diastolic volume. Healthy subjects were recruited as controls. RESULTS: MicroRNA-155 measured on day 5 correlated positively with the relative change in end-diastolic volume (ρ = 0.490, p = 0.028). MicroRNA-155 (day 5) was significantly higher in patients with compared to patients without adverse LV remodeling. The expression level was similar in healthy subjects (n = 8) and in patients with LV remodeling. There was a positive correlation between microRNA-155 and the amount of monocytes (day 5, ρ = 0.463, p = 0.046). CONCLUSION: Impaired downregulation of microRNA-155 during the second phase of the post- STEMI inflammatory response is a determinant of the development of adverse LV remodeling.

Hepatocellular autophagy modulates the unfolded protein response and fasting-induced steatosis in mice.

Autophagy and the unfolded protein response (UPR) are key cellular homeostatic mechanisms and are both involved in liver diseases, including nonalcoholic fatty liver disease (NAFLD). Although increasing but conflicting results link these mechanisms to lipid metabolism, their role and potential cross talk herein have been poorly investigated. Therefore, we assessed the effects of hepatocyte-specific autophagy deficiency on liver parenchyma, the UPR, and lipid metabolism. Adult hepatocellular-specific autophagy-deficient mice (Atg7F/FAlb-Cre+) were compared with their autophagy-competent littermates (Atg7+/+Alb-Cre+). Livers were analyzed by electron microscopy, histology, real-time qPCR, and Western blotting. Atg7F/FAlb-Cre+ mice developed hepatomegaly with significant parenchymal injury, as shown by inflammatory infiltrates, hepatocellular apoptosis, pericellular fibrosis, and a pronounced ductular reaction. Surprisingly, the UPR exhibited a pathway-selective pattern upon autophagy deficiency. The activity of the adaptive activating transcription factor 6 (ATF6) pathway was abolished, whereas the proapoptotic protein kinase RNA-like ER kinase pathway was increased compared with Atg7+/+Alb-Cre+ mice. The inositol-requiring enzyme-1α signal was unaltered. Fasting-induced steatosis was absent in Atg7F/FAlb-Cre+ mice. Remarkably, some isolated islands of fat-containing and autophagy-competent cells were observed in these livers. Hepatocellular autophagy is essential for parenchymal integrity in mice. Moreover, in the case of autophagy deficiency, the three different UPR branches are pathway selectively modulated. Attenuation of the ATF6 pathway might explain the observed impairment of fasting-induced steatosis. Finally, autophagy and lipid droplets are directly linked to each other.

Linking CD11b (+) Dendritic Cells and Natural Killer T Cells to Plaque Inflammation in Atherosclerosis.

Atherosclerosis remains the leading cause of death and disability in our Western society. To investigate whether the dynamics of leukocyte (sub)populations could be predictive for plaque inflammation during atherosclerosis, we analyzed innate and adaptive immune cell distributions in blood, plaques, and lymphoid tissue reservoirs in apolipoprotein E-deficient (ApoE(-/-)) mice and in blood and plaques from patients undergoing endarterectomy. Firstly, there was predominance of the CD11b(+) conventional dendritic cell (cDC) subset in the plaque. Secondly, a strong inverse correlation was observed between CD11b(+) cDC or natural killer T (NKT) cells in blood and markers of inflammation in the plaque (including CD3, T-bet, CCR5, and CCR7). This indicates that circulating CD11b(+) cDC and NKT cells show great potential to reflect the inflammatory status in the atherosclerotic plaque. Our results suggest that distinct changes in inflammatory cell dynamics may carry biomarker potential reflecting atherosclerotic lesion progression. This not only is crucial for a better understanding of the immunopathogenesis but also bares therapeutic potential, since immune cell-based therapies are emerging as a promising novel strategy in the battle against atherosclerosis and its associated comorbidities. The cDC-NKT cell interaction in atherosclerosis serves as a good candidate for future investigations.

12 Weeks of Combined Endurance and Resistance Training Reduces Innate Markers of Inflammation in a Randomized Controlled Clinical Trial in Patients with Multiple Sclerosis.

Previously, we reported that patients with multiple sclerosis (MS) demonstrate improved muscle strength, exercise tolerance, and lean tissue mass following a combined endurance and resistance exercise program. However, the effect of exercise on the underlying disease pathogenesis remains elusive. Since recent evidence supports a crucial role of dendritic cells (DC) in the pathogenesis of MS, we investigated the effect of a 12-week combined exercise program in MS patients on the number and function of DC. We demonstrate an increased number of plasmacytoid DC (pDC) following the exercise program. These pDC display an activated phenotype, as evidenced by increased numbers of circulating CD62L(+) and CD80(+) pDC. Interestingly, the number of CD80(+) pDC positively correlates with the presence of IL-10-producing regulatory type 1 cells (Tr1), an important cell type for maintaining peripheral tolerance to self-antigens. In addition, decreased production of the inflammatory mediators, TNF-α and MMP-9, upon Toll-like receptor (TLR) stimulation was found at the end of the exercise program. Overall, our findings suggest that the 12-week exercise program reduces the secretion of inflammatory mediators upon TLR stimulation and promotes the immunoregulatory function of circulating pDC, suggestive for a favorable impact of exercise on the underlying immunopathogenesis of MS.

Content validity of workplace-based portfolios: A multi-centre study.

BACKGROUND: Portfolios are used as tools to coach and assess students in the workplace. This study sought to evaluate the content validity of portfolios as reflected in their capacity to adequately assess achieved competences of medical students during clerkships. METHODS: We reviewed 120 workplace portfolios at three medical universities (Belgium and the Netherlands). To validate their content, we developed a Validity Inventory for Portfolio Assessment (VIPA) based on the CanMEDS roles. Two raters evaluated each portfolio and indicated for each VIPA item whether the portfolio provided sufficient information to enable satisfactory assessment of the item. We ran a descriptive analysis on the validation data and computed Cohen's Kappa to investigate interrater agreement. RESULTS: The portfolios adequately covered the items pertaining to the communicator (90%) and professional (87%) roles. Coverage of the medical expert, collaborator, scholar and manager roles ranged between 75% and 85%. The health advocate role, covering 59%, was clearly less well represented. This role also exhibited little interrater agreement (Kappa < 0.4). CONCLUSIONS: This study lends further credence to the evidence that portfolios can indeed adequately assess the different CanMEDS roles during clerkships, the health advocate role, which was less well represented in the portfolio content, excepted.