Event-free survival of maralixibat-treated patients with Alagille syndrome compared to a real-world cohort from GALA.

BACKGROUND AND AIMS: Alagille syndrome (ALGS) is characterized by chronic cholestasis with associated pruritus and extrahepatic anomalies. Maralixibat, an ileal bile acid transporter inhibitor, is an approved pharmacologic therapy for cholestatic pruritus in ALGS. Since long-term placebo-controlled studies are not feasible or ethical in children with rare diseases, a novel approach was taken comparing 6-year outcomes from maralixibat trials with an aligned and harmonized natural history cohort from the G lobal AL agille A lliance (GALA) study. APPROACH AND RESULTS: Maralixibat trials comprise 84 patients with ALGS with up to 6 years of treatment. GALA contains retrospective data from 1438 participants. GALA was filtered to align with key maralixibat eligibility criteria, yielding 469 participants. Serum bile acids could not be included in the GALA filtering criteria as these are not routinely performed in clinical practice. Index time was determined through maximum likelihood estimation in an effort to align the disease severity between the two cohorts with the initiation of maralixibat. Event-free survival, defined as the time to first event of manifestations of portal hypertension (variceal bleeding, ascites requiring therapy), surgical biliary diversion, liver transplant, or death, was analyzed by Cox proportional hazards methods. Sensitivity analyses and adjustments for covariates were applied. Age, total bilirubin, gamma-glutamyl transferase, and alanine aminotransferase were balanced between groups with no statistical differences. Event-free survival in the maralixibat cohort was significantly better than the GALA cohort (HR, 0.305; 95% CI, 0.189-0.491; p <0.0001). Multiple sensitivity and subgroup analyses (including serum bile acid availability) showed similar findings. CONCLUSIONS: This study demonstrates a novel application of a robust statistical method to evaluate outcomes in long-term intervention studies where placebo comparisons are not feasible, providing wide application for rare diseases. This comparison with real-world natural history data suggests that maralixibat improves event-free survival in patients with ALGS.

Natural history of liver disease in a large international cohort of children with Alagille syndrome: Results from the GALA study.

BACKGROUND AND AIMS: Alagille syndrome (ALGS) is a multisystem disorder, characterized by cholestasis. Existing outcome data are largely derived from tertiary centers, and real-world data are lacking. This study aimed to elucidate the natural history of liver disease in a contemporary, international cohort of children with ALGS. APPROACH AND RESULTS: This was a multicenter retrospective study of children with a clinically and/or genetically confirmed ALGS diagnosis, born between January 1997 and August 2019. Native liver survival (NLS) and event-free survival rates were assessed. Cox models were constructed to identify early biochemical predictors of clinically evident portal hypertension (CEPH) and NLS. In total, 1433 children (57% male) from 67 centers in 29 countries were included. The 10 and 18-year NLS rates were 54.4% and 40.3%. By 10 and 18 years, 51.5% and 66.0% of children with ALGS experienced ≥1 adverse liver-related event (CEPH, transplant, or death). Children (>6 and ≤12 months) with median total bilirubin (TB) levels between ≥5.0 and <10.0 mg/dl had a 4.1-fold (95% confidence interval [CI], 1.6-10.8), and those ≥10.0 mg/dl had an 8.0-fold (95% CI, 3.4-18.4) increased risk of developing CEPH compared with those <5.0 mg/dl. Median TB levels between ≥5.0 and <10.0 mg/dl and >10.0 mg/dl were associated with a 4.8 (95% CI, 2.4-9.7) and 15.6 (95% CI, 8.7-28.2) increased risk of transplantation relative to <5.0 mg/dl. Median TB <5.0 mg/dl were associated with higher NLS rates relative to ≥5.0 mg/dl, with 79% reaching adulthood with native liver ( p < 0.001). CONCLUSIONS: In this large international cohort of ALGS, only 40.3% of children reach adulthood with their native liver. A TB <5.0 mg/dl between 6 and 12 months of age is associated with better hepatic outcomes. These thresholds provide clinicians with an objective tool to assist with clinical decision-making and in the evaluation of therapies.

Quantitative BONCAT Allows Identification of Newly Synthesized Proteins after Optic Nerve Injury.

Retinal ganglion cells (RGCs) die after optic nerve trauma or in degenerative disease. However, acute changes in protein expression that may regulate RGC response to injury are not fully understood, and detailed methods to quantify new protein synthesis have not been tested. Here, we develop and apply a new in vivo quantitative measure of newly synthesized proteins to examine changes occurring in the retina after optic nerve injury. Azidohomoalanine, a noncanonical amino acid, was injected intravitreally into the eyes of rodents of either sex with or without optic nerve injury. Isotope variants of biotin-alkyne were used for quantitative BONCAT (QBONCAT) mass spectrometry, allowing identification of protein synthesis and transport rate changes in more than 1000 proteins at 1 or 5 d after optic nerve injury. In vitro screening showed several newly synthesized proteins regulate axon outgrowth in primary neurons in vitro This novel approach to targeted quantification of newly synthesized proteins after injury uncovers a dynamic translational response within broader proteostasis regulation and enhances our understanding of the cellular response to injury.SIGNIFICANCE STATEMENT Optic nerve injury results in death and degeneration of retinal ganglion cells and their axons. The specific cellular response to injury, including changes in new protein synthesis, is obscured by existing proteins and protein degradation. In this study, we introduce QBONCAT to isolate and quantify acute protein synthesis and subsequent transport between cellular compartments. We identify novel candidate protein effectors of the regenerative response and uncover their regulation of axon growth in vitro, validating the utility of QBONCAT for the discovery of novel regulatory and therapeutic candidates after optic nerve injury.

A high-sensitivity phospho-switch triggered by Cdk1 governs chromosome morphogenesis during cell division.

The initiation of chromosome morphogenesis marks the beginning of mitosis in all eukaryotic cells. Although many effectors of chromatin compaction have been reported, the nature and design of the essential trigger for global chromosome assembly remain unknown. Here we reveal the identity of the core mechanism responsible for chromosome morphogenesis in early mitosis. We show that the unique sensitivity of the chromosome condensation machinery for the kinase activity of Cdk1 acts as a major driving force for the compaction of chromatin at mitotic entry. This sensitivity is imparted by multisite phosphorylation of a conserved chromatin-binding sensor, the Smc4 protein. The multisite phosphorylation of this sensor integrates the activation state of Cdk1 with the dynamic binding of the condensation machinery to chromatin. Abrogation of this event leads to chromosome segregation defects and lethality, while moderate reduction reveals the existence of a novel chromatin transition state specific to mitosis, the intertwist configuration. Collectively, our results identify the mechanistic basis governing chromosome morphogenesis in early mitosis and how distinct chromatin compaction states can be established via specific thresholds of Cdk1 kinase activity.

Karyopherin Kap114p-mediated trans-repression controls ribosomal gene expression under saline stress.

Nuclear accessibility of transcription factors controls gene expression, co-regulated by Ran-dependent nuclear localization and a competitive regulatory network. Here, we reveal that nuclear import factor-facilitated transcriptional repression attenuates ribosome biogenesis under chronic salt stress. Kap114p, one of the karyopherin-ßs (Kap-ßs) that mediates nuclear import of yeast TATA-binding protein (yTBP), exhibits a yTBP-binding affinity four orders of magnitude greater than its counterparts and suppresses binding of yTBP with DNA. Our crystal structure of Kap114p reveals an extensively negatively charged concave surface, accounting for high-affinity basic-protein binding. KAP114 knockout in yeast leads to a high-salt growth defect, with transcriptomic analyses revealing that Kap114p modulates expression of genes associated with ribosomal biogenesis by suppressing yTBP binding to target promoters, a trans-repression mechanism we attribute to reduced nuclear Ran levels under salinity stress. Our findings reveal that Ran integrates the nuclear transport pathway and transcription regulatory network, allowing yeast to respond to environmental stresses.

Normal Gamma Glutamyl Transferase Levels at Presentation Predict Poor Outcome in Biliary Atresia.

OBJECTIVES: Gamma-glutamyl transferase levels (GGT) are typically elevated in biliary atresia (BA), but normal GGT levels have been observed. This cohort of "normal GGT" BA has neither been described nor has the prognostic value of GGT level on outcomes in BA. We aimed to describe outcomes of a single-centre Australian cohort of infants with BA and assess the impact of GGT level at presentation on outcomes in BA. METHODS: Infants diagnosed with BA between 1991 and 2017 were retrospectively analysed. Outcomes were defined as survival with native liver, liver transplantation (LT), and death. Patients were categorized into normal (<200I U/L) or high GGT groups based on a mean of 3 consecutive GGT values done before Kasai portoenterostomy (KPE). Baseline parameters, age at surgery, clearance of jaundice (COJ), and outcomes were compared between the 2 groups. RESULTS: One hundred thirteen infants underwent KPE at median 61 (30-149) days. At a median follow-up of 14.2 (0.9-26.3) years, 35% (39/113) patients were surviving with native liver, 55% (62/113) underwent LT and 11% (12/113) died pretransplant. 12.3% (14/113) patients had normal GGT. Age at KPE and time to COJ were similar between normal and high GGT groups. Normal GGT group had shorter time from KPE to LT (11 vs 18 months, P = 0.02), underwent LT at a younger age (14 vs 20 months, P = 0.04), and had poorer transplant-free survival (P = 0.04) than high GGT group. CONCLUSIONS: 12.3% of infants with BA had normal GGT levels at diagnosis. Low GGT levels at presentation in BA was associated with a poorer outcome.

Chronic diarrhoea in children: A practical algorithm-based approach.

Diarrhoea is a leading cause of morbidity and mortality world-wide. Most diarrhoeal episodes are acute and infectious in origin. Diarrhoea lasting for longer than 4 weeks with no discernible infectious aetiology warrants thorough evaluation. The aim of this review is to elucidate an approach to evaluation of diarrhoea based on its pathophysiologic mechanisms with focus on aetiology, investigation and management of chronic diarrhoea. It includes a brief description of normal fluid homeostasis in the gut and pathophysiology of diarrhoea. Further, diarrhoea is classified as 'watery', 'fatty' and 'bloody' based on stool characteristics. Relevant history, physical examination findings, first and second-line investigations which help in differentiating the different types of diarrhoea are listed and an algorithmic approach to individual types of diarrhoea has been devised. Principles of management and recent advances in diagnostics and therapeutics of diarrhoea are briefly discussed.

Combined liver and pancreas transplantation in two children with cystic fibrosis-First experience in Australia and New Zealand.

We report the first two pediatric patients with CF who underwent successful combined liver-pancreas transplantation in Australia and New Zealand for CF liver disease and CF-related diabetes mellitus.

EXPRESS: On the interchangeability of presentation order for cause and effect: Experimental tests of cue and outcome density effects.

Studies of cue-outcome contingency learning demonstrate outcome-density effects: participants typically overestimate contingencies when the outcome event is relatively frequent. Equivalent cue-density effects occur, though these have been examined less often. Few studies have simultaneously examined both those event density effects or have manipulated the presentation order of the events,limiting knowledge of whether these phenomena share underlying principles-. We report three well-powered experiments to address those gaps. Participants judged the effectiveness of a medical treatment after viewing a series of pairings for two events, a cause (treatment given vs. not) and an effect (patient recovered vs. not). Experiment 1 manipulated both event densities independently. We then manipulated the presentation order for the cause and the effect, alongside a manipulation of effect density (Experiment 2a) or cause density (Experiment 2b). Experiment 1 found a large main effect of event-density (η_p^2 =.55), which was qualified by a significant interaction between event type and density level (η_p^2 =.10) whereby effect density had greater impact than cause density. Experiments 2a and 2b found effects for effect-density (η_p^2=.60) and cause-density (η_p^2=.31). The effects of cause-effect presentation order were always small and non-significant. We conclude that effect-density manipulations had substantial impact on contingency judgments, and cause-density manipulations less so. Moreover, it matters little which event (cause or effect) is seen first. These findings have implications for contingency, associative, probabilistic, and causal models of contingency judgment; primarily, that people may be more sensitive to the causal status of events than to their temporal order of presentation.

Shared Decision-Making at the Intersection of Disability, Culture, and Language Accessibility: An Educational Session for Medical Students.

Introduction: People with disabilities and those with non-English language preferences have worse health outcomes than their counterparts due to barriers to communication and poor continuity of care. As members of both groups, people who are Deaf users of American Sign Language have compounded health disparities. Provider discomfort with these specific demographics is a contributing factor, often stemming from insufficient training in medical programs. To help address these health disparities, we created a session on disability, language, and communication for undergraduate medical students. Methods: This 2-hour session was developed as a part of a 2020 curriculum shift for a total of 404 second-year medical student participants. We utilized a retrospective postsession survey to analyze learning objective achievement through a comparison of medians using the Wilcoxon signed rank test (α = .05) for the first 2 years of course implementation. Results: When assessing 158 students' self-perceived abilities to perform each of the learning objectives, students reported significantly higher confidence after the session compared to their retrospective presession confidence for all four learning objectives (ps < .001, respectively). Responses signifying learning objective achievement (scores of 4, probably yes, or 5, definitely yes), when averaged across the first 2 years of implementation, increased from 73% before the session to 98% after the session. Discussion: Our evaluation suggests medical students could benefit from increased educational initiatives on disability culture and health disparities caused by barriers to communication, to strengthen cultural humility, the delivery of health care, and, ultimately, health equity.

DYRK1A signalling synchronizes the mitochondrial import pathways for metabolic rewiring.

Mitochondria require an extensive proteome to maintain a variety of metabolic reactions, and changes in cellular demand depend on rapid adaptation of the mitochondrial protein composition. The TOM complex, the organellar entry gate for mitochondrial precursors in the outer membrane, is a target for cytosolic kinases to modulate protein influx. DYRK1A phosphorylation of the carrier import receptor TOM70 at Ser91 enables its efficient docking and thus transfer of precursor proteins to the TOM complex. Here, we probe TOM70 phosphorylation in molecular detail and find that TOM70 is not a CK2 target nor import receptor for MIC19 as previously suggested. Instead, we identify TOM20 as a MIC19 import receptor and show off-target inhibition of the DYRK1A-TOM70 axis with the clinically used CK2 inhibitor CX4945 which activates TOM20-dependent import pathways. Taken together, modulation of DYRK1A signalling adapts the central mitochondrial protein entry gate via synchronization of TOM70- and TOM20-dependent import pathways for metabolic rewiring. Thus, DYRK1A emerges as a cytosolic surveillance kinase to regulate and fine-tune mitochondrial protein biogenesis.

Diagnosis and management of pediatric acute liver failure: consensus recommendations of the Indian Society of Pediatric Gastroenterology, Hepatology, and Nutrition (ISPGHAN).

Timely diagnosis and management of pediatric acute liver failure (PALF) is of paramount importance to improve survival. The Indian Society of Pediatric Gastroenterology, Hepatology, and Nutrition invited national and international experts to identify and review important management and research questions. These covered the definition, age appropriate stepwise workup for the etiology, non-invasive diagnosis and management of cerebral edema, prognostic scores, criteria for listing for liver transplantation (LT) and bridging therapies in PALF. Statements and recommendations based on evidences assessed using the modified Grading of Recommendations Assessment, Development and Evaluation (GRADE) system were developed, deliberated and critically reappraised by circulation. The final consensus recommendations along with relevant published background information are presented here. We expect that these recommendations would be followed by the pediatric and adult medical fraternity to improve the outcomes of PALF patients.

Diet and Management of Diarrhea.

Diet plays an important role in human health and disease. Of all human diseases, diarrheal illnesses bring diet into sharp focus as it has a direct causal and therapeutic relationship. With the advent and widespread use of next generation sequencing, significant advances have been made in unraveling the etiologies of congenital diarrheas and enteropathies, some of which are eminently treatable with dietary modification. Early institution of appropriate dietary therapy is lifesaving in congenital osmotic diarrheas. Chronic diarrhea in older children and adolescents often have an underlying dietary basis, depending on the etiology. Identification and exclusion of the offending food in the diet results in dramatic improvement in symptoms. It is equally important to be prudent and cautious in the use of exclusion diets in management of chronic diarrhea as it is associated with micronutrient deficiencies, needless escalation of cost and enable maladaptive food intake behaviors. In this review, authors discuss etiology specific dietary management of diarrhea in children with emphasis on congenital diarrheas and enteropathies.

Characterization of CFTR mutations in people with cystic fibrosis and severe liver disease who are not eligible for CFTR modulators.

Cystic-fibrosis-related liver disease (CFLD) is a variable phenotype of CF. The severe CFLD variant with cirrhosis or portal hypertension has a poor prognosis and life expectancy. CFTR modulator therapies are now available for people with CF and eligibility for such treatment is based on their CFTR genotype. We evaluated the genetic eligibility for elexacaftor, tezacaftor, ivacaftor (ETI), and ivacaftor (IVA) monotherapy in a previously reported CF cohort of 1591 people with CF of whom 171 with severe CFLD. Based on their CFTR mutations, 13% (N=184/1420) of subjects without CFLD and 11% (N=19/171) of those with severe CFLD are not eligible for either ETI or IVA therapy. The non-eligible patients without CFLD or with severe CFLD can currently not take advantage of the potential benefits of these new treatments. Although this study cannot provide any data regarding the effect of ETI or IVA on the progression of severe CFLD, the consequences for ineligibility of patients with extreme liver phenotype may be even more significant because of their poorer disease risk profile.

A New Variant of an Old Itch: Novel Missense Variant in ABCB4 Presenting with Intractable Pruritus.

We report a novel homozygous missense variant in ABCB4 gene in a Yemeni child born to consanguineous parents, with a significant family history of liver disease-related deaths, resulting in a progressive familial intrahepatic cholestasis (PFIC) type 3 phenotype requiring liver transplantation for intractable pruritus.

Α γ-tubulin complex-dependent pathway suppresses ciliogenesis by promoting cilia disassembly.

The primary cilium, a microtubule-based sensory organelle, undergoes cycles of assembly and disassembly that govern the cell cycle progression critical to cell proliferation and differentiation. Although cilia assembly has been studied extensively, the molecular mechanisms underlying cilia disassembly are less well understood. Here, we uncover a γ-tubulin ring complex (γ-TuRC)-dependent pathway that promotes cilia disassembly and thereby prevents cilia formation. We further demonstrate that Kif2A, a kinesin motor that bears microtubule-depolymerizing activity, is recruited to the cilium basal body in a γ-TuRC-dependent manner. Our mechanistic analyses show that γ-TuRC specifically recruits Kif2A via the GCP2 subunit and its binding partner Mzt2. Hence, despite the long-standing view that γ-TuRC acts mainly as a microtubule template, we illustrate that its functional heterogeneity at the basal body facilitates both microtubule nucleation and Kif2A recruitment-mediated regulation of ciliogenesis, ensuring cell cycle progression.

Phase separation and zinc-induced transition modulate synaptic distribution and association of autism-linked CTTNBP2 and SHANK3.

Many synaptic proteins form biological condensates via liquid-liquid phase separation (LLPS). Synaptopathy, a key feature of autism spectrum disorders (ASD), is likely relevant to the impaired phase separation and/or transition of ASD-linked synaptic proteins. Here, we report that LLPS and zinc-induced liquid-to-gel phase transition regulate the synaptic distribution and protein-protein interaction of cortactin-binding protein 2 (CTTNBP2), an ASD-linked protein. CTTNBP2 forms self-assembled condensates through its C-terminal intrinsically disordered region and facilitates SHANK3 co-condensation at dendritic spines. Zinc binds the N-terminal coiled-coil region of CTTNBP2, promoting higher-order assemblies. Consequently, it leads to reduce CTTNBP2 mobility and enhance the stability and synaptic retention of CTTNBP2 condensates. Moreover, ASD-linked mutations alter condensate formation and synaptic retention of CTTNBP2 and impair mouse social behaviors, which are all ameliorated by zinc supplementation. Our study suggests the relevance of condensate formation and zinc-induced phase transition to the synaptic distribution and function of ASD-linked proteins.

Adverse Events Associated With the Addition of Aspirin to Direct Oral Anticoagulant Therapy Without a Clear Indication.

Importance: It is unclear how many patients treated with a direct oral anticoagulant (DOAC) are using concomitant acetylsalicylic acid (ASA, or aspirin) and how this affects clinical outcomes. Objective: To evaluate the frequency and outcomes of prescription of concomitant ASA and DOAC therapy for patients with atrial fibrillation (AF) or venous thromboembolic disease (VTE). Design, Setting, and Participants: This registry-based cohort study took place at 4 anticoagulation clinics in Michigan from January 2015 to December 2019. Eligible participants were adults undergoing treatment with a DOAC for AF or VTE, without a recent myocardial infarction (MI) or history of heart valve replacement, with at least 3 months of follow-up. Exposures: Use of ASA concomitant with DOAC therapy. Main Outcomes and Measures: Rates of bleeding (any, nonmajor, major), rates of thrombosis (stroke, VTE, MI), emergency department visits, hospitalizations, and death. Results: Of the study cohort of 3280 patients (1673 [51.0%] men; mean [SD] age 68.2 [13.3] years), 1107 (33.8%) patients without a clear indication for ASA were being treated with DOACs and ASA. Two propensity score-matched cohorts, each with 1047 patients, were analyzed (DOAC plus ASA and DOAC only). Patients were followed up for a mean (SD) of 20.9 (19.0) months. Patients taking DOAC and ASA experienced more bleeding events compared with DOAC monotherapy (26.0 bleeds vs 31.6 bleeds per 100 patient years, P = .01). Specifically, patients undergoing combination therapy had significantly higher rates of nonmajor bleeding (26.1 bleeds vs 21.7 bleeds per 100 patient years, P = .02) compared with DOAC monotherapy. Major bleeding rates were similar between the 2 cohorts. Thrombotic event rates were also similar between the cohorts (2.5 events vs 2.3 events per 100 patient years for patients treated with DOAC and ASA compared with DOAC monotherapy, P = .80). Patients were more often hospitalized while undergoing combination therapy (9.1 vs 6.5 admissions per 100 patient years, P = .02). Conclusion and Relevance: Nearly one-third of patients with AF and/or VTE who were treated with a DOAC received ASA without a clear indication. Compared with DOAC monotherapy, concurrent DOAC and ASA use was associated with increased bleeding and hospitalizations but similar observed thrombosis rate. Future research should identify and deprescribe ASA for patients when the risk exceeds the anticipated benefit.