BACKGROUND AND AIMS:N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations are influenced by age, which may influence the diagnostic performance of this peptide. Machine learning approaches incorporating NT-proBNP and age as continuous measures may have improved diagnostic performance. METHODS:We pooled individual patient-level data for 10 369 patients [median age 73 years (25th-75th percentile: 59-82)] with suspected acute heart failure across fourteen studies. The diagnostic performance of guideline-recommended NT-proBNP thresholds (uniform rule-out threshold of 300 pg/mL and age-stratified rule-in thresholds of 450, 900, and 1800 pg/mL for patients <50, 50-75, and >75 years, respectively) and the Collaboration for the Diagnosis and Evaluation of Heart Failure (CoDE-HF) machine learning model were evaluated using random effects meta-analysis across age groups. RESULTS:Overall, 43.9% (4549/10 369) of patients had an adjudicated diagnosis of acute heart failure. The negative predictive value (NPV) of the rule-out threshold of 300 pg/mL was lower in older patients [NPV 88.7% (confidence interval (CI) 84.2-92.1%) in patients ≥80 years vs 98.9% (97.6-99.5%) <50 years]. Conversely, the positive predictive value (PPV) of age-stratified rule-in thresholds was lower in younger patients [PPV 62.0% (56.2-67.5%) in those <50 years vs 79.6% (70.7-86.3%) ≥80 years]. CoDE-HF was more accurate than guideline-recommended thresholds across all age groups, with NPV and PPV ranging from 96.4% to 99.5% (93.8-99.8% CIs) and 81.1% to 84.2% (74.7-90.4% CIs), respectively. CONCLUSION:The diagnostic performance of guideline-recommended thresholds of NT-proBNP varies significantly with age. A decision-support tool incorporating NT-proBNP with age as a continuous variable provides a more consistent and accurate approach.

Alkali salts of the common fluorosurfactant 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanesulfonic acid (6:2 FTSA) exhibit a remarkably low solubility in water, which enables the precipitation of these salts from water. The same applies for the corresponding ammonium salt 6:2 FTS NH4 which can be obtained in crystalline form by slowly adding aqueous ammonia to an aqueous solution of FTSA. To understand the cause of this behavior on a molecular basis, an X-ray single crystal structure determination of 6:2 FTS NH4 was performed, allowing to further examine the molecular interactions in the solid state responsible for its low solubility. A hydrogenbonded layer structure results from four distinct N-H & sdot;& sdot;& sdot;O interactions, that involve all four NH groups, the given ammonium ion and sulfonate-O atoms belonging to four different anion units. Columns of parallel aligned fluoroalkyl chains dominate the packing of molecules in the crystal. The characterization was accompanied by thermal as well as spectroscopic analysis. The lack of hygroscopicity and its high thermal stability make 6:2 FTS NH(4 )a suitable gravimetric standard substance for analytical applications. HPLC MS/MS measurements showed that 6:2 FTS NH4 can adequately substitute commercial 13C labelled compounds at least for routine analysis of common perfluorinated contaminants using standard internal calibration.

Background/Objectives: Soluble ST2 (sST2) has gained recognition as a clinically relevant biomarker across a spectrum of inflammatory, cardiovascular, and respiratory conditions. However, the lack of assay standardization raises concerns about result comparability across platforms and studies. Methods: This study systematically evaluated serum sST2 concentrations measured with two ELISA systems-DuoSet and Quantikine-produced by the same manufacturer (R&D Systems, Minneapolis, MN, USA). Results: Using archived serum samples from healthy volunteers and marathon runners, we identified marked discrepancies: serum sST2 concentrations using the DuoSet recombinant standard were on average 4.3-fold higher than those using Quantikine (median 308.3 [106.6-608.6] vs. 71.5 [41.8-115.6] ng/mL). On the pre-coated Quantikine plate, using the DuoSet recombinant standard increased calculated concentrations 4.3-fold compared with the native Quantikine standard (median 308.3 [106.6-608.6] vs. 71.5 [41.8-115.6] ng/mL). On the manually coated DuoSet plate, the DuoSet standard yielded higher medians than the Quantikine standard (8.0 [5.6-11.3] vs. 5.0 [3.7-7.4] ng/mL). Furthermore, between-lot variability within the same ELISA platform resulted in concentration shifts from 0.09 [0.07-0.10] ng/mL (2016) to 1.17 [0.81-3.23] ng/mL (2023) using the same sample. Previously published studies also exhibited wide inter-study variability among healthy cohorts. Conclusions: These findings emphasize that current ELISA systems for sST2 are not standardized and that cross-study comparisons should be interpreted with caution. Until universal standardization is implemented, sST2 should primarily be used for within-study comparisons. This variability may limit the reliability of longitudinal sST2 assessment even in clinical settings.

Proprotein convertase 1/3 (PC1/3), encoded by PCSK1, is expressed in neuronal and endocrine cell types, where it activates a number of protein precursors that play roles in energy homeostasis. Biallelic PCSK1 loss-of-function mutations cause a polyendocrinopathy; a total of 34 patients were reported. An infant with congenital malabsorptive diarrhea of all carbohydrates underwent exome sequencing (ES), with particular consideration of PC1/3 deficiency, but no mutations were found. The onset of obesity in the second year of life increased suspicion of PC1/3 deficiency in the proband, as well as in his equally affected cousin. Transcript analysis revealed minor amounts of an aberrant PCSK1 transcript containing intron 9 sequence and encoding a premature stop codon (p.Pro400Valfs*35). A deep intronic PCSK1 variant, NG_021161.1(NM_000439.5):c.1196+2681T>A, was found to segregate in the proband's family with the disease. A minigene approach demonstrated that the identified deep-intronic variant underlies pseudo-exon inclusion of the intron 9 sequence in the transcript. The characteristic phenotype of PC1/3 deficiency might require extended genetic testing to make a timely diagnosis.

AIMS:B-type natriuretic peptide (BNP) and mid-regional pro-atrial natriuretic peptide (MR-proANP) testing are guideline-recommended to aid in the diagnosis of acute heart failure. Nevertheless, the diagnostic performance of these biomarkers is uncertain. METHODS AND RESULTS:We performed a systematic review and individual patient-level data meta-analysis to evaluate the diagnostic performance of BNP and MR-proANP. We subsequently developed and externally validated a decision-support tool called CoDE-HF that combines natriuretic peptide concentrations with clinical variables using machine learning to report the probability of acute heart failure. Fourteen studies from 12 countries provided individual patient-level data in 8493 patients for BNP and 3899 patients for MR-proANP, in whom, 48.3% (4105/8493) and 41.3% (1611/3899) had an adjudicated diagnosis of acute heart failure, respectively. The negative predictive value (NPV) of guideline-recommended thresholds for BNP (100 pg/mL) and MR-proANP (120 pmol/L) was 93.6% (95% confidence interval 88.4-96.6%) and 95.6% (92.2-97.6%), respectively, whilst the positive predictive value (PPV) was 68.8% (62.9-74.2%) and 64.8% (56.3-72.5%). Significant heterogeneity in the performance of these thresholds was observed across important subgroups. CoDE-HF was well calibrated with excellent discrimination in those without prior acute heart failure for both BNP and MR-proANP [area under the curve of 0.914 (0.906-0.921) and 0.929 (0.919-0.939), and Brier scores of 0.110 and 0.094, respectively]. CoDE-HF with BNP and MR-proANP identified 30% and 48% as low-probability [NPV of 98.5% (97.1-99.3%) and 98.5% (97.7-99.0%)], and 30% and 28% as high-probability [PPV of 78.6% (70.4-85.0%) and 75.1% (70.9-78.9%)], respectively, and performed consistently across subgroups. CONCLUSION:The diagnostic performance of guideline-recommended BNP and MR-proANP thresholds for acute heart failure varied significantly across patient subgroups. A decision-support tool that combines natriuretic peptides and clinical variables was more accurate and supports more individualized diagnosis. STUDY REGISTRATION:PROSPERO number, CRD42019159407.

Carbamoyl phosphate synthetase 1 (CPS1) and ornithine transcarbamylase (OTC) deficiencies are rare urea cycle disorders, which can lead to life-threatening hyperammonemia. Liver transplantation (LT) provides a cure and offers an alternative to medical treatment and life-long dietary restrictions with permanent impending risk of hyperammonemia. Nevertheless, in most patients, metabolic aberrations persist after LT, especially low plasma citrulline levels, with questionable clinical impact. So far, little is known about these alterations and there is no consensus, whether l-citrulline substitution after LT improves patients' symptoms and outcomes. In this multicentre, retrospective, observational study of 24 patients who underwent LT for CPS1 (n = 11) or OTC (n = 13) deficiency, 25% did not receive l-citrulline or arginine substitution. Correlation analysis revealed no correlation between substitution dosage and citrulline levels (CPS1, p = 0.8 and OTC, p = 1). Arginine levels after liver transplantation were normal after LT independent of citrulline substitution. Native liver survival had no impact on mental impairment (p = 0.67). Regression analysis showed no correlation between l-citrulline substitution and failure to thrive (p = 0.611) or neurological outcome (p = 0.701). Peak ammonia had a significant effect on mental impairment (p = 0.017). Peak plasma ammonia levels correlate with mental impairment after LT in CPS1 and OTC deficiency. Growth and intellectual impairment after LT are not significantly associated with l-citrulline substitution.

Breakdown of chlorophyll (Chl), as studied in angiosperms, follows the pheophorbide a oxygenase/phyllobilin (PaO/PB) pathway, furnishing linear tetrapyrroles, named phyllobilins (PBs). In an investigation with fern leaves we have discovered iso-phyllobilanones (iPBs) with an intriguingly rearranged and oxidized carbon skeleton. We report here a key second group of iPBs from the fern and on their structure analysis. Previously, these additional Chl-catabolites escaped their characterization, since they exist in aqueous media as mixtures of equilibrating isomers. However, their chemical dehydration furnished stable iPB-derivatives that allowed the delineation of the enigmatic structures and chemistry of the original natural catabolites. The structures of all fern-iPBs reflect the early core steps of a PaO/PB-type pathway and the PB-to-iPB carbon skeleton rearrangement. A striking further degradative chemical ring-cleavage was observed, proposed to consume singlet molecular oxygen (1O2). Hence, Chl-catabolites may play a novel active role in detoxifying cellular 1O2. The critical deviations from the PaO/PB pathway, found in the fern, reflect evolutionary developments of Chl-breakdown in the green plants in the Paleozoic era. Bilin-type chlorophyll-catabolites in de-greened leaves of the bracken fern and of some angiosperms are molecular reporters of a common basic pathway of Chl-breakdown in two widely different plant divisions. However, the Chl-catabolite structures were revealed to also differ in striking ways, shedding light on the evolution of specific Chl-breakdown strategies in early land plants that existed in the Paleozoic, as progenitors of the extant flora. image

BACKGROUND AND AIMS:To systematically review the literature for reports on Wolcott-Rallison syndrome, focusing on the spectrum and natural history, genotype-phenotype correlations, patient and native liver survival, and long-term outcomes. METHODS:PubMed, Livio, Google Scholar, Scopus and Web of Science databases were searched. Data on genotype, phenotype, therapy, cause of death and follow-up were extracted. Survival and correlation analyses were performed. RESULTS:Sixty-two studies with 159 patients met the inclusion criteria and additional 30 WRS individuals were collected by personal contact. The median age of presentation was 2.5 months (IQR 2) and of death was 36 months (IQR 50.75). The most frequent clinical feature was neonatal diabetes in all patients, followed by liver impairment in 73%, impaired growth in 72%, skeletal abnormalities in 59.8%, the nervous system in 37.6%, the kidney in 35.4%, insufficient haematopoiesis in 34.4%, hypothyroidism in 14.8% and exocrine pancreas insufficiency in 10.6%. Episodes of acute liver failure were frequently reported. Liver transplantation was performed in six, combined liver-pancreas in one and combined liver-pancreas-kidney transplantation in two individuals. Patient survival was significantly better in the transplant cohort (p = .0057). One-, five- and ten-year patient survival rates were 89.4%, 65.5% and 53.1%, respectively. Liver failure was reported as the leading cause of death in 17.9% of cases. Overall survival was better in individuals with missense mutations (p = .013). CONCLUSION:Wolcott-Rallison syndrome has variable clinical courses. Overall survival is better in individuals with missense mutations. Liver- or multi-organ transplantation is a feasible treatment option to improve survival.

Mass spectrometry imaging (MSI) is a powerful analytical technique for the two-dimensional (2D) localization of chemicals on surfaces. Conventional MSI experiments require to predefine the surface of interest based on photographic or microscopic images. Typically, these boundaries can no longer be changed or adjusted once the experiment has been started. In terms of a more interactive approach we recently developed a pen-like ionization interface which is directly connected to the mass spectrometer. The device allows the user to ionize chemicals by desorption electrospray ionization (DESI) and to freely move the interface over a surface of interest. A mini camera, which is mounted on the tip of the pen, magnifies the desorption area and enables a simple positioning of the pen. The combination of optical data from the camera module and chemical data obtained by mass analysis facilitates a novel type of imaging experiment: interactive mass spectrometry imaging (IMSI). For this application, we present a novel approach for a robust, optical flow-based motion detection. While the live video stream from the camera is used to track the pen's motion across the surface a post-acquisition algorithm correlates the coordinates of the pen trajectory with respective mass spectra obtained from a simultaneous mass spectrometric data acquisition. This algorithm is no longer dependent on a single, manually applied optical marker on the sample surface, which has to be visible on all video frames throughout the analysis. The advanced DESI-IMSI method was successfully tested on inkjet-printed letters as well as mouse brain tissue samples. Validation of the results was done by comparing DESI-IMSI with standard DESI-MSI data.

Tropaeolum majus (garden nasturtium) is a plant with relevance in phytomedicine, appreciated not only for its pharmaceutical activities, but also for its beautiful leaves and flowers. Here, we investigated the phytochemical composition of senescent nasturtium leaves. Indeed, we identified yellow chlorophyll catabolites, also termed phylloxanthobilins, which we show to contribute to the bright yellow color of the leaves in the autumn season. Moreover, we isolated and characterized the phylloxanthobilins from T. majus , and report the identification of a pyro-phylloxanthobilin, so far only accessible by chemical synthesis. We show that the phylloxanthobilins contribute to bioactivities of T. majus by displaying strong anti-oxidative effects in vitro and in cellulo , and anti-inflammatory effects as assessed by COX-1 and COX-2 enzyme inhibition, similar to other bioactive ingredients of T. majus , isoquercitrin, and chlorogenic acid. Hence, phylloxanthobilins could play a role in the efficacy of T. majus in the treatment of urinary tract infections, an established indication of T. majus. With the results shown in this study, we aid in the completion of the phytochemical profile of T. majus by identifying additional bioactive natural products as relevant components of this medicinal plant.

Background: Pediatric acute liver failure (PALF) is a rare and life-threatening condition. In up to 50% of PALF cases, the underlying etiology remains unknown during routine clinical testing. This lack of knowledge complicates clinical management and liver transplantation decisions. Recently, whole-exome sequencing has identified genetic disorders in a large number of cases without specific laboratory biomarkers or metabolic fingerprints. Methods: We describe how further analysis of whole-exome sequencing data combined with proteomic analyses in 5 previously unsolved PALF patients, where no pathogenic variants in genes previously associated with acute liver failure were identified, revealed rare biallelic variants in transient receptor potential cation channel subfamily M member 7 (TRPM7). Results: We establishe TRPM7 as a novel disease gene for PALF. Yet, the cation channel kinase TRPM7 has not been associated with any Mendelian disorder. No homozygous loss-of-function variants were found in in-house exomes or publicly available databases. Rare biallelic TRPM7-variants were significantly enriched in the PALF cohort compared with a pediatric control cohort. Viral infections preceded the majority of PALF episodes. Recurrent PALF episodes characterized the disease course with rapid progression, leading to early death in 3 cases. Proteomic analyses of patient fibroblasts unveiled significantly reduced TRPM7 protein levels, indicative of functional impairment. Severely reduced Mg2+ levels in one individual with a mutation in the channel domain suggests a potential interaction between disturbed Mg2+ homeostasis and PALF. The consistent presence of mutations in the TRPM7 protein-kinase-domain across all patients suggests its specific relevance in PALF. Conclusions: Our data extend the genetic spectrum of recurrent PALF and prompt consideration of TRPM7 in children with unexplained liver failure.

Exome sequencing (ES) has identified biallelic kinesin family member 12 ( KIF12 ) mutations as underlying neonatal cholestatic liver disease. We collected information on onset and progression of this entity. Among consecutively referred pediatric patients at our centers, diagnostic ES identified 4 patients with novel, biallelic KIF12 variants using the human GRCh38 reference sequence, as KIF12 remains incompletely annotated in the older reference sequence GRCh37. A review of these and of 21 reported patients with KIF12 variants found that presentation with elevated serum transaminase activity in the context of trivial respiratory infection, without clinical features of liver disease, was more common ( n  = 18) than manifest cholestatic disease progressing rapidly to liver transplantation (LT; n  = 7). Onset of liver disease was at age <1 year in 15 patients; LT was more common in this group. Serum gamma-glutamyl transpeptidase activity (GGT) was elevated in all patients, and total bilirubin was elevated in 15 patients. Liver fibrosis or cirrhosis was present in 14 of 18 patients who were biopsied. The 16 different pathogenic variants and 11 different KIF12 genotypes found were not correlated with age of onset or progression to LT. Identification of biallelic pathogenic KIF12 variants distinguishes KIF12-related disease from other entities with elevated GGT.

Objective: Congenital, non-syndromic orofacial clefts (CL/P) are infrequently monogenic in etiology. However, heterozygous pathogenic CDH1 germline variants were reported in a few non-syndromic CL/P families, as well as in one syndromic form of CL/P: the blepharocheilodontic syndrome. CDH1 encodes epithelial cadherin (E-cadherin), and close to 300 different pathogenic CDH1 variants are listed in the ClinVar mutation database. The majority of CDH1 germline variants are implicated in hereditary diffuse gastric cancer (HDGC) susceptibility. The purpose of this study was to classify the CDH1 c.760G>A (p.Asp254Asn) mutation with respect to its resulting phenotype. Methods: Exome sequencing and targeted Sanger sequencing were performed in a family segregating CL/P. A review of pathogenic CDH1 variants in ClinVar and those identified in a PubMed/MEDLINE search was performed. Results: We identified a family with six individuals, who were 35-77 years old (mean 56 years) at their last examination, uniformly affected with bilateral CL/P. The CDH1 c.760G>A variant segregated with CL/P. This variant had been reported in 21 individuals, most often children and young adults, from six families. We determined a significant sex preponderance for this variant regarding CL/P: all 16 male and 5 of 11 female heterozygotes presented with CL/P. Furthermore, none of the heterozygous individuals in seven families reported any gastrointestinal tumors. Conclusions: The recurrent CDH1 c.760G>A mutation confers a high risk for CL/P, with strong male preponderance. This review of 27 mutation carriers, including 3 who were 68, 70, and 77 years of age, indicates that c.760G>A does not confer an increased risk for HDGC. The relevance of differentiating craniofacial from cancer phenotypes in mutation carriers is substantial for precision medicine and for counseling families.

BACKGROUND:Metabolic dysfunction-associated steatotic liver disease (MASLD) is considered multifactorial with a number of predisposing gene polymorphisms known. METHODS:The occurrence of MASLD in 7 and 10 year old siblings, one without classical risk factors and one with type 2 diabetes suggested a monogenic etiology and prompted next-generation sequencing. Exome sequencing was performed in the proband, both parents and both siblings. The impact of a likely disease-causing DNA variant was assessed on the transcript and protein level. RESULTS:Two siblings have hepatomegaly, elevated serum transaminase activity, and steatosis and harbor a homozygous DECR1 splice-site variant, c.330+3A>T. The variant caused DECR1 transcript decay. Immunostaining demonstrated lack of DECR1 in patient liver. CONCLUSIONS:These patients may represent the first individuals with DECR1 deficiency, then defining within MASLD an autosomal-recessive entity, well corresponding to the reported steatotic liver disease in Decr1 knockout mice. DECR1 may need to be considered in the genetic work-up of MASLD.

center dot PURPOSE: To report the genetic etiology of Lisch ep-ithelial corneal dystrophy (LECD). center dot DESIGN: Multicenter cohort study. center dot METHODS: A discovery cohort of 27 individuals with LECD from 17 families, including 7 affected members from the original LECD family, 6 patients from 2 new families and 14 simplex cases, was recruited. A cohort of 6 individuals carrying a pathogenic MCOLN1 (mu-colipin 1) variant was reviewed for signs of LECD. Next-generation sequencing or targeted Sanger sequenc- ing were used in all patients to identify pathogenic or likely pathogenic variants and penetrance of variants. RESULTS: Nine rare heterozygous MCOLN1 variants were identified in 23 of 27 affected individuals from 13 families. The truncating nature of 7 variants and functional testing of 1 missense variant indicated that they result in MCOLN1 haploinsufficiency. Importantly, in the homozygous and compound-heterozygous state, 4 of 9 LECD-associated variants cause the rare lysoso- mal storage disorder mucolipidosis IV (MLIV). Auto- somal recessive MLIV is a systemic disease and com- prises neurodegeneration as well as corneal opacity of infantile-onset with epithelial autofluorescent lysosomal inclusions. However, the 6 parents of 3 patients with MLIV confirmed to carry pathogenic MCOLN1 variants did not have the LECD phenotype, suggesting MCOLN1 haploinsufficiency may be associated with reduced pene- trance and variable expressivity. CONCLUSIONS: MCOLN1 haploinsufficiency is the major cause of LECD. Based on the overlap- ping clinical features of corneal epithelial cells with autofluorescent inclusions reported in both LECD and MLIV, it is concluded that some carriers of MCOLN1 haploinsufficiency-causing variants present with LECD. (Am J Ophthalmol 2024;258: 183-195. (c) 2023 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC li- cense (http://creativecommons.org/licenses/by-nc/4.0/))

Epithelial polarization and polarized cargo transport are highly coordinated and interdependent processes. In our search for novel regulators of epithelial polarization and protein secretion, we used a genome-wide CRISPR/Cas9 screen and combined it with an assay based on fluorescence-activated cell sorting (FACS) to measure the secretion of the apical brush-border hydrolase dipeptidyl peptidase 4 (DPP4). In this way, we performed the first CRISPR screen to date in human polarized epithelial cells. Using high-resolution microscopy, we detected polarization defects and mislocalization of DPP4 to late endosomes/lysosomes after knockout of TM9SF4, anoctamin 8, and ARHGAP33, confirming the identification of novel factors for epithelial polarization and apical cargo secretion. Thus, we provide a powerful tool suitable for studying polarization and cargo secretion in epithelial cells. In addition, we provide a dataset that serves as a resource for the study of novel mechanisms for epithelial polarization and polarized transport and facilitates the investigation of novel congenital diseases associated with these processes.

New trinuclear water reduction catalysts show turnover numbers for photochemical water splitting of up to 8899, a turnover frequency of 2737 h −1 and an incident photon conversion efficiency of 2.1%, thus outperforming mononuclear analogues.

Background: Biliary atresia (BA) causes neonatal cholestasis and rapidly progresses into cirrhosis if left untreated. Kasai portoenterostomy may delay cirrhosis. BA remains among the most common indications for liver transplantation (LT) during childhood. Liver function and gut microbiome are interconnected. Disturbed liver function and enterohepatic signaling influence microbial diversity. We, herein, investigate the impact of LT and reestablishment of bile flow on gut microbiome–bile acid homeostasis in children with BA before (pre, n = 10), 3 months (post3m, n = 12), 12 months (post12m, n = 9), and more than 24 months (post24 + m, n = 12) after LT. Methods: We analyzed the intestinal microbiome of BA patients before and after LT by 16S-rRNA-sequencing and bioinformatics analyses, and serum primary and secondary bile acid levels. Results: The gut microbiome in BA patients exhibits a markedly reduced alpha diversity in pre ( p = 0.015) and post3m group ( p = 0.044), and approximated healthy control groups at later timepoints post12m ( p = 1.0) and post24 + m ( p = 0.74). Beta diversity analysis showed overall community structure similarities of pre and post3m ( p = 0.675), but both differed from the post24 + m ( p < 0.001). Longitudinal analysis of the composition of the gut microbiome revealed the Klebsiella genus to show increased abundance in the post24 + m group compared with an age-matched control ( p = 0.029). Secondary bile acid production increased 2+ years after LT ( p = 0.03). Multivariable associations of microbial communities and clinical metadata reveal several significant associations of microbial genera with tacrolimus and mycophenolate mofetil–based immunosuppressive regimens. Conclusions: In children with BA, the gut microbiome shows strongly reduced diversity before and shortly after LT, and approximates healthy controls at later timepoints. Changes in diversity correlate with altered secondary bile acid synthesis at 2+ years and with the selection of different immunosuppressants.