Challenges and physiological implications of sarcopenia in children and youth in health and disease.

PURPOSE OF REVIEW: Highlight the controversies and challenges associated with a sarcopenia diagnosis in infants and children and the potential physiological mechanisms contributing to this disorder. RECENT FINDINGS: Sarcopenia has been recently identified in infants and children with chronic diseases such as liver, cardiac, gastrointestinal, cancer and organ transplant recipients. However, there is no consensus regarding the definition of pediatric sarcopenia. Different sarcopenic phenotypes (sarcopenia and sarcopenic obesity) have been identified in healthy children and children with chronic disease. Both conditions have been associated with adverse clinical outcomes (e.g. delayed growth, increased hospitalization) in children and youth with chronic disease. The etiology of pediatric sarcopenia is likely multifactorial associated with malnutrition, physical inactivity and altered metabolic environments influencing skeletal muscle mass accumulation and function. Gaps in the literature include the lack of standard tools that should be used for the evaluation of skeletal muscular fitness and body composition in sarcopenia, particularly in infants and young children (<4years). SUMMARY: Longitudinal evaluation of sarcopenia expression and the underlying physiological and lifestyle factors contributing to pediatric sarcopenia are important to understand to ensure effective rehabilitation strategies can be developed and to avoid the adverse clinical consequences in children.

Exercise rehabilitation to treat sarcopenia in pediatric transplant populations.

BACKGROUND: In adult transplant (Tx) populations, exercise rehabilitation strategies may improve sarcopenia components (muscle mass [MM], strength [MS], and physical performance [PP]). Limited data are available regarding exercise rehabilitation therapy in pediatric Tx populations. METHODS: The purpose of this review is to critically evaluate the feasibility and impact of exercise programs (EP) that include resistance exercise (RE) on markers of sarcopenia in pediatric Tx populations. Literature searches in SCOPUS and WEB OF SCIENCE were conducted to identify studies applying EP with a RE component in pediatric populations in the Tx setting. RESULTS: Twelve articles (2008-2022) met inclusion criteria. The exercise interventions varied in length (3 weeks-12 months), intensity (low to moderate), time pre/post Tx (0 days-5 years post Tx), age of participants (3-18 years), adherence (63%-94%), and methodologies to measure components of sarcopenia. No studies measured all three components of sarcopenia concurrently. Approximately, 60% of studies found positive effects on MS and PP. Only one pediatric study measured body composition, therefore, the effect of exercise programs with RE components on MM is unknown. CONCLUSIONS: Exercise programs may be a beneficial treatment for sarcopenia in Tx populations, particularly in components of MS and PP. Studies measuring all three aspects of sarcopenia together in response to RE training in pediatrics remains an important gap. Studies that include body composition measurements in response to exercise are needed. Special considerations for the development of RE programs in pediatrics Tx populations are safety, supervision, engagement through family/peer involvement and incorporation of game/play-based elements.

Immunomodulatory role of thrombin in cancer progression.

Coagulation proteases and the generation of thrombin are increased in tumors. In addition, chemotherapeutic agents commonly used to treat malignant cancers can exacerbate cancer-associated thromboses. Thrombin can modify tumor cell behavior directly through the activation of protease-activated receptors (PAR) or indirectly by generating fibrin matrices. In addition to its role in generating fibrin to promote hemostasis, thrombin acts directly on multiple effector cells of the immune system impacting both acute and chronic inflammatory processes. Thrombin-mediated release of interleukin-6, tumor necrosis factor-α, and monocyte chemoattractant protein-1 leads to the accumulation of multiple tumor-infiltrating immunosuppressive cell populations including myeloid derived suppresser cells, M2-like macrophages, and T regulatory cells. Ablation of PAR-1 from the tumor microenvironment, but not the tumor, has been shown to dramatically reduce tumor growth and metastasis in multiple tumor models. Thrombin-activated platelets release immunosuppressive cytokines including transforming growth factor-ß that can inhibit natural killer cell activity, helping tumor cells to evade host immunosurveillance. Taken together, there is strong evidence that thrombin influences cancer progression via multiple mechanisms, including the tumor immune response, with thrombin emerging as a target for novel therapeutic strategies for cancer.

Pharmacokinetics, Safety, and Efficacy of Glecaprevir/Pibrentasvir in Children With Chronic HCV: Part 2 of the DORA Study.

BACKGROUND AND AIMS: Glecaprevir/pibrentasvir (GLE/PIB) has shown high efficacy and safety in chronic HCV-infected adults and adolescents; data in children were limited. DORA part 2 is a phase 2/3, nonrandomized, open-label study evaluating the pharmacokinetics, efficacy, and safety of a pediatric formulation of GLE and PIB in children ages 3 to < 12 years. APPROACH AND RESULTS: Children with chronic HCV infection, genotype 1-6, with or without compensated cirrhosis, were divided into three cohorts by age-cohort 2 (9 to < 12 years), cohort 3 (6 to < 9 years), and cohort 4 (3 to < 6 years)-and given weight-based doses of GLE and PIB for 8, 12, or 16 weeks. Primary endpoints were sustained virologic response at posttreatment week 12 (SVR12) and steady-state exposure; secondary endpoints were rates of persistent viremia, relapse, and reinfection. Safety and laboratory abnormalities were assessed. Final pediatric dosages determined to be efficacious were 250 mg GLE + 100 mg PIB (in children weighing ≥ 30 to < 45 kg), 200 mg GLE + 80 mg PIB (≥ 20 to < 30 kg), and 150 mg GLE + 60 mg PIB (12 to < 20 kg). Of 80 participants enrolled and dosed, 96% (77/80) achieved SVR12. One participant, on the initial dose ratio, relapsed by posttreatment week 4; no participants had virologic failures on the final dose ratio of GLE 50 mg/PIB 20 mg. Two nonresponders prematurely discontinued the study. Most adverse events (AEs) were mild; no drug-related serious AEs occurred. Pharmacokinetic exposures were comparable to those of adults. CONCLUSIONS: A pediatric formulation of GLE/PIB was highly efficacious and well tolerated in chronic HCV-infected children 3 to < 12 years old.

Severity of COVID-19 among solid organ transplant recipients in Canada, 2020-2021: a prospective, multicentre cohort study.

BACKGROUND: Severe COVID-19 appears to disproportionately affect people who are immunocompromised, although Canadian data in this context are limited. We sought to determine factors associated with severe COVID-19 outcomes among recipients of organ transplants across Canada. METHODS: We performed a multicentre, prospective cohort study of all recipients of solid organ transplants from 9 transplant programs in Canada who received a diagnosis of COVID-19 from March 2020 to November 2021. Data were analyzed to determine risk factors for oxygen requirement and other metrics of disease severity. We compared outcomes by organ transplant type and examined changes in outcomes over time. We performed a multivariable analysis to determine variables associated with need for supplemental oxygen. RESULTS: A total of 509 patients with solid organ transplants had confirmed COVID-19 during the study period. Risk factors associated with needing (n = 190), compared with not needing (n = 319), supplemental oxygen included age (median 62.6 yr, interquartile range [IQR] 52.5-69.5 yr v. median 55.5 yr, IQR 47.5-66.5; p < 0.001) and number of comorbidities (median 3, IQR 2-3 v. median 2, IQR 1-3; p < 0.001), as well as parameters associated with immunosuppression. Recipients of lung transplants (n = 48) were more likely to have severe disease with a high mortality rate (n = 15, 31.3%) compared with recipients of other organ transplants, including kidney (n = 48, 14.8%), heart (n = 1, 4.4%), liver (n = 9, 11.4%) and kidney-pancreas (n = 3, 12.0%) transplants (p = 0.02). Protective factors against needing supplemental oxygen included having had a liver transplant and receiving azathioprine. Having had 2 doses of SARS-CoV-2 vaccine did not have an appreciable influence on oxygen requirement. Multivariable analysis showed that older age (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.02-1.07) and number of comorbidities (OR 1.63, 95% CI 1.30-2.04), among other factors, were associated with the need for supplemental oxygen. Over time, disease severity did not decline significantly. INTERPRETATION: Despite therapeutic advances and vaccination of recipients of solid organ transplants, evidence of increased severity of COVID-19, in particular among those with lung transplants, supports ongoing public health measures to protect these at-risk people, and early use of COVID-19 therapies for recipients of solid organ transplants.

Immunologic benefits of maternal living donor allografts in pediatric liver transplantation: fewer rejection episodes and no evidence of de novo allosensitization.

BACKGROUND: Pediatric liver transplant (LT) recipients of maternal living liver donor (LLD) grafts have been reported to experience fewer rejection episodes. However, it is unclear whether this benefit translates to reduction in developing donor-specific antibody (DSA) among maternal-LLD recipients. The aim of this study was to compare immunologic outcomes among maternal-LLD, non-maternal-LLD, and deceased donor liver transplant (DDLT) recipients. METHODS: Children (≤18 years) who underwent LT between 1/1998 and 12/2019 at two high-volume LT centers in North America were evaluated. Patients were divided into three groups by type of graft received (maternal-LLD, non-maternal LLD, and DDLT). Clinical variables and outcomes were compared according to each graft type. RESULTS: A total of 450 pediatric primary LT were analyzed: 275 (61.1%) DDLT, 73 (16.2%) maternal-LLD, and 102 (22.6%) non-maternal-LLD. Children receiving LLD grafts were less likely to develop rejection when compared to the DDLT group (DDLT 46.9% vs. maternal-LLD 31.5% vs. non-maternal-LLD 28.4%, p = 0.001). There was no difference in rejection rates between maternal and non-maternal-LLD recipients. A higher percentage of maternal-LLD recipients were on immunosuppression monotherapy compared to non-maternal-LLD and DDLT recipients (6.7% vs. 1.2 vs. 2.4%, respectively). A subgroup of 68 patients were tested for DSA post-LT. Maternal-LLD recipients were less likely to develop de novo DSA (maternal-LLD 11.8% vs. non-maternal-LLD 19.3% vs. DDLT 43%, p = 0.018). None of the maternal-LLD recipients developed antibody-mediated rejection. CONCLUSIONS: These data support the concept of immunologic benefit of maternal-LLD in pediatric LT, with lower rates of rejection and allosensitization post-LT when compared to DDLT recipients.

The effects of child anxiety and depression on concordance between parent-proxy and self-reported health-related quality of life for pediatric liver transplant patients.

BACKGROUND: HRQOL is a key outcome following pediatric LT. Parent-proxy reports may substitute for patients unable to report their own HRQOL. This study compared parent-proxy and self-reported HRQOL in children who have undergone LT. METHODS: Pediatric LT recipients between the ages of 8 and 18 years, and a parent, completed self and proxy versions of the PeLTQL questionnaire, PedsQL Generic and Transplant modules, and standardized measures of depression and anxiety. RESULTS: Data from 129 parent-patient dyads were included. Median parent age was 44 years, and most (89%) were mothers. Median patient age was 2.5 years at LT and 13.6 years at the time of study participation. Parents had significantly lower scores than patients on PedsQL total generic (70.8 ± 18.5 and 74.3 ± 19.0, p = .01), PeLTQL coping and adjustment (63.0 ± 15.6 and 67.3 ± 16.2, p < .01), and social-emotional (66.3 ± 14.9 and 71.9 ± 15.6, p < .001) domains. Higher patient anxiety and depression were related to larger absolute differences between parent-proxy and self-reported scores on all HRQOL measures (all p < .05). In this disparity, parents reported higher HRQOL scores than their child as self-reported anxiety and depression scores increased. CONCLUSIONS: Differences in concordance between parent-proxy and self-reported HRQOL scores can be more prominent when children have more symptoms of anxiety and depression. Children's mental health symptoms should be queried, if feasible, when interpreting differences in parent and child reports of HRQOL.

Deficits in Muscle Strength and Physical Performance Influence Physical Activity in Sarcopenic Children After Liver Transplantation.

Sarcopenia is a muscle disease characterized by reduced skeletal muscle mass (SMM), muscle strength, and physical performance. Reduced SMM has been identified in children after liver transplantation (LT), but no information related to muscle strength/physical performance or lifestyle factors contributing to sarcopenia is available. We hypothesized that sarcopenia, as determined by measures of SMM, muscle strength, and physical performance, is highly prevalent in children after LT and is related to poor diet quality (DQ) and physical inactivity. A cross-sectional study in post-LT children (n = 22) and age-matched healthy controls (n = 47) between the ages of 6 and 18 years examining body composition (dual energy X-ray absorptiometry and multiple skinfold), measures of muscle strength (handgrip, sit-to-stand, and push-ups), physical performance (6-minute walk test and stair climb test), diet (3-day food intake), and physical activity (accelerometer) was conducted. Low muscle strength/physical performance and SMM (SMM z scores ≤-1.5) were defined by values 2 standard deviations below the mean values for age- and sex-matched controls. Sarcopenia occurred in 36% of children who underwent LT, and they had significantly lower scores for muscle strength (sit-to-stand and push-up tests) and physical performance (stair climb test) than controls (P < 0.05). Deficits in physical performance in children with sarcopenia were predominantly revealed by longer stair climbing times (P = 0.03), with no differences in other muscle tests. Low SMM, muscle strength, and physical performance were associated with a lower amount of time spent in fairly and very active physical activity, but no associations with DQ were found. Sarcopenia is highly prevalent in children after LT and is related to lower moderate-to-vigorous physical activity. Development of effective rehabilitation strategies to treat sarcopenia are needed in post-LT children.

Polyamine-stimulation of arsenic-transformed keratinocytes.

Tumor promotion is strongly associated with inflammation and increased polyamine levels. Our understanding of relevant mechanisms responsible for arsenic-induced cancer remains limited. Previous studies suggest that arsenic targets and dysregulates stem cell populations that remain dormant in the skin until promoted to be recruited out of the bulge stem cell region, thus giving rise to skin tumors. In this study, we explored a possible mechanism by which increased keratinocyte polyamine biosynthesis promotes tumorsphere formation and invasiveness of arsenic-transformed HaCaT keratinocytes (As-HaCaT). Unlike parental HaCaT cells, As-HaCaT cells were tumorigenic in athymic nude mice, and the CD45negative epithelial tumor cells had enriched expression of Toll-Like Receptor 4 (TLR4), CD34 and CXCR4 as did As-HaCaT tumorsphere cultures compared to As-HaCaT monolayer cultures. Ornithine decarboxylase (ODC) overexpressing keratinocytes (Ker/ODC) release increased levels of the alarmin high mobility group box 1 (HMGB1). Ker/ODC conditioned medium (CM) stimulated As-HaCaT but not parental HaCaT tumorsphere formation, and this was inhibited by glycyrrhizin, an inhibitor of HMGB1, and by TAK242, an inhibitor of the HMGB1 receptor TLR4. Compared to parental HaCaT cells, As-HaCaT cells demonstrated greater invasiveness across a Matrigel-coated filter using either fibroblast CM or SDF-1α as chemoattractants. Addition of Ker/ODC CM or HMGB1 dramatically increased As-HaCaT invasiveness. Glycyrrhizin and TAK242 inhibited this Ker/ODC CM-stimulated invasion of As-HaCaT cells but not HaCaT cells. These results show that polyamine-dependent release of HMGB1 promotes the expansion of stem cell-like subpopulations in arsenic-transformed keratinocytes while also increasing their invasiveness, suggesting that polyamines may be a potential therapeutic target for the prevention and treatment of arsenic-initiated skin cancers.

Preclinical study of the long-range safety and anti-inflammatory effects of high-dose oral meglumine.

Meglumine is a methylamino derivative of sorbitol that is an approved drug excipient. Recent preclinical studies suggest that administration of high-dose oral meglumine can exert beneficial medicinal effects to treat diabetes, obesity, and fatty liver disease (NAFLD/nonalcoholic steatohepatitis [NASH]). Here we address gaps in knowledge about the pharmacology and toxicology of this substance administered at high concentrations to explore its medicinal potential. We observed that high-dose meglumine limited secretion of proinflammatory cytokines and cell adhesion molecules from activated human THP-1 or murine RAW264.7 monocytes. Preclinical pharmacokinetic analysis in Swiss mice confirmed that meglumine was orally available. Informed by this data, oral doses of 18 to 75 mM meglumine were administered ad libitum in the drinking water of Sprague-Dawley rats and two cohorts of C57BL/6 mice housed in different vivariums. In a 32-week study, urinary isoprostane levels trended lower in subjects consistent with the possibility of anti-inflammatory effects. In full lifespan studies, there was no detrimental effect on longevity. Heart function evaluated in C57BL/6 mice using an established noninvasive cardiac imaging system showed no detrimental effects on ejection fraction, fractional shortening, left ventricle function or volume, and cardiac output in mice up to 15-month old, with a potential positive trend in heart function noted in elderly mice consistent with earlier reported benefits on muscle stamina. Finally, in a transgenic model of inflammation-associated skin carcinogenesis, the incidence, number, and growth of skin tumors trended lower in subjects receiving meglumine. Overall, the evidence obtained illustrating the long-range safety of high-dose oral meglumine support the rationale for its evaluation as a low-cost modality to limit diabetes, hypertriglyceridemia, and NAFLD/NASH.

Sarcopenia in Chronic Liver Disease: Impact on Outcomes.

Malnutrition is a common complication in patients with end-stage liver disease (ESLD) awaiting liver transplantation (LT). Malnutrition and sarcopenia overlap in etiology and outcomes, with sarcopenia being defined as reduced skeletal muscle mass and muscle function. The purpose of this review was to identify the prevalence of sarcopenia with and without obesity in adults and children with ESLD and to assess the methodological considerations in sarcopenia diagnosis and the association of sarcopenia with pre- and post-LT outcomes. A total of 38 articles (35 adult and 3 pediatric articles) retrieved from PubMed or Web of Science databases were included. In adults, the prevalence rates of pre-LT sarcopenia, pre-LT sarcopenic obesity (SO), post-LT sarcopenia, and post-LT SO were 14%-78%, 2%-42%, 30%-100%, and 88%, respectively. Only 2 adult studies assessed muscle function in patients diagnosed with sarcopenia. The presence of pre-LT sarcopenia is associated with higher wait-list mortality, greater postoperative mortality, higher infection risk and postoperative complications, longer intensive care unit (ICU) stay, and ventilator dependency. The emerging pediatric data suggest that sarcopenia is prevalent in pre- and post-LT periods. In 1 pediatric study, sarcopenia was associated with poor growth, longer perioperative length of stay (total/ICU) and ventilator dependency, and increased rehospitalization in children after LT. In conclusion, there is a high prevalence of sarcopenia in adults and children with ESLD. Sarcopenia is associated with adverse clinical outcomes. The present review is limited by heterogeneity in the definition of sarcopenia and in the methodological approaches in assessing sarcopenia. Future studies are needed to standardize the sarcopenia diagnosis and muscle function assessment, particularly in the pediatric population, to enable early identification and treatment of sarcopenia in adults and children with ESLD.

Healthy Body Weights With Corticosteroid-free Immunosuppression Is the Best Predictor of Cardiovascular Health in Children After Liver Transplantation.

INTRODUCTION: Cardiometabolic dysregulation (CMD) influences morbidity and mortality risk in adults post-liver transplantation (LTx). CMD is reported in 10% to 25% of pediatric LTx recipients, but no information regarding the longitudinal expression of CMD is available. The study objective was to examine the longitudinal expression of CMD and associations with body composition and growth in children post-LTx. METHODS: A retrospective review was conducted in youth (34 F/30 M) who underwent LTx between 1994 and 2015 at the Stollery Children's Hospital. Primary outcomes included serum markers of CMD (insulin, glucose, hemoglobin A1C [A1C], homeostasis model assessment for insulin resistance [abnormal >3], lipid panel triglycerides, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol) and systolic/diastolic blood pressure (BP: absolute/z scores). RESULTS: Mean (±SD) age, weight z, height z, body mass index z was 9.7 ±â€Š3.4 years (3.5-17.9), 0.26 ±â€Š1.03, 0.017 ±â€Š1.2, and 0.41 ±â€Š1.05, respectively. The majority of children had percentage fat mass, percentage fat-free mass within normal reference ranges. Systolic/diastolic BP was within healthy references ranges in 83.1% and 93.5% of children, respectively. Serum insulin (83.4%) and high-density lipoprotein-cholesterol (43.9%) concentrations were low, with abnormal findings of other laboratory markers found in <5% of participants. Abnormal findings for metabolic parameters were independent of weight z, body mass index z, fat mass, and corticosteroids but were positively related to child's age (>9.7 years) and fat-free mass (total, arms). Insulin levels decreased significantly in the first 4 years post-LTx, but no changes in lipid panel, A1C and glucose were noted over 10 years. CONCLUSIONS: Pediatric LTx recipients with healthy body weights and corticosteroid-free immunosuppression have a low expression of CMD over 10 years.

Case series and systematic review of acquired diaphragmatic hernia after liver transplantation.

BACKGROUND: ADH is a rare and potentially fatal complication following LT. In this study, a systematic review was completed to identify risk factors which may contribute to ADH. METHODS: Transplant databases at three LT programs were reviewed. Four pediatric and zero adult cases were identified. Next, a systematic review was completed. Fourteen studies describing 41 patients with ADH were identified. Patient demographics, transplant characteristics, and features of ADH diagnosis were examined. RESULTS: The majority (90.2%) of ADH were in children. In pediatric LT, 95.1% received a segmental allograft. ADH occurred in the right P diaphragm 92.7% of the time, and 87.8% were repaired primarily. Patient demographics, post-transplant complications, and immunosuppression regimens were broad and failed to predict ADH. Most patients presented with either respiratory or gastrointestinal symptoms. There were two pediatric deaths related to undiagnosed ADH. The combined worldwide incidence of ADH in pediatric LT is 1.5% (34/2319 patients). CONCLUSION: ADH is a rare complication post-LT that primarily occurs in pediatric recipients. When diagnosed early, ADH can be repaired primarily with good outcomes.

Diet quality of children post-liver transplantation does not differ from healthy children.

Little has been studied regarding the diets of children following LTX. The study aim was to assess and compare dietary intake and DQ of healthy children and children post-LTX. Children and adolescents (2-18 years) post-LTX (n=27) and healthy children (n=28) were studied. Anthropometric and demographic data and two 24-hour recalls (one weekend; one weekday) were collected. Intake of added sugar, HFCS, fructose, GI, and GL was calculated. DQ was measured using three validated DQ indices: the HEI-C, the DGI-CA, and the DQI-I. Although no differences in weight-for-age z-scores were observed between groups, children post-LTX had lower height-for-age z-scores than healthy children (P<.01). With the exception of vitamin B12, no significant differences in energy and macronutrient (protein, carbohydrate, and fat), added sugar, HFCS, fructose, GI, GL, and micronutrient intakes and DQ indices (HEI-C, DGI-CA, and DQI-I) between groups were observed (P>.05). The majority of children in both groups (>40%) had low DQ scores. No significant interrelationships between dietary intake, anthropometric, and demographic were found (P>.05). Both healthy and children post-LTX consume diets with poor DQ. This has implications for risk of obesity and metabolic dysregulation, particularly in transplant populations on immunosuppressive therapies.

Value of serum cystatin C in estimating renal function in children with non-renal solid organ transplantation.

Children with non-renal solid organ transplants are surviving longer, but outcome is complicated by CKD. Accurate and frequent renal function monitoring is imperative to recognize and institute measures early to reverse, prevent, or arrest progression. This study of 59 children determined the accuracy (P30), bias, sensitivity and specificity between measured renal function by NM-GFR, and estimated GFR by three formulas: Filler (serum cystatin C), mSchwartz (serum creatinine), and CKiD (serum cystatin C, creatinine, urea, and height). Mean GFR by all formulas differed significantly from NM-GFR. Filler and mSchwartz formulas significantly increased the proportion of patients with GFR ≥ 90 mL/min/1.73 m(2) (CKD stage 1) while decreasing those with GFR 60-89 mL/min/1.73 m(2) (CKD stage 2). All formulas overestimated GFR. CKiD showed the highest P30 and lowest bias (79.7%; 6.9 mL/min/1.73 m(2) ) followed by Filler (67.7%; 19.9 mL/min/1.73 m(2) ) and Schwartz (57.6%; 26.8 mL/min/1.73 m(2) ) for all GFR values. All formulas performed best with GFR ≥ 90 mL/min/1.73 m(2) , but CKiD was the only formula to achieve 91.1% accuracy. All formulas showed high sensitivities, but low specificities at NM-GFR cutoff at 90. Thus, GFR estimated by CKiD followed by Filler formula is an adequate method to monitor renal function closely and frequently in these children.

Development and validation of the pediatric liver transplantation quality of life: a disease-specific quality of life measure for pediatric liver transplant recipients.

OBJECTIVES: To develop and validate a Pediatric Liver Transplantation Quality of Life (PeLTQL) questionnaire via an international multicenter collaboration. STUDY DESIGN: Item generation with 146 child and/or parent interviews (92 pediatric liver transplantation [LT] recipients) and 3 focus groups generated over 300 items. An item reduction questionnaire with 76 questions was completed by 320 participants (212 pediatric LT recipients). RESULTS: Frequency-importance product ranking, questionnaire formatting, and pre-testing resulted in a 26-item PeLTQL questionnaire. Factor analysis identified 3 domains: future health, coping and adjustment, and social-emotional. The validation phase was completed by 133 (46% male) LT recipients (aged 8-18 years). Internal consistency (Cronbach α = 0.86) and test-retest reliability (intraclass correlation coefficient = 0.85) were excellent. Mean patient PeLTQL score was 69.54 ± 13.06. Construct validity with validated tools identified significant correlations between mean PeLTQL scores and (1) Pediatric Quality of Life Inventory generic (r = 0.64, P < .001); (2) Pediatric Quality of Life Inventory transplant (r = 0.73, P < .001); and (3) Screen for Child Anxiety Related Disorders (r = -0.57, P < .001) scores. Only 17/3458 (0.5%) questions were left blank. A Flesch-Kincaid grade level of 5.4 was calculated as a measure of the PeLTQL readability statistic. CONCLUSIONS: The PeLTQL is a valid and reliable novel 26-item disease-specific health related quality of life instrument for LT recipients aged 8-18 years. Low PeLTQL scores can identify patients at risk for childhood anxiety and depression. The tool is now ready for broad use in both clinical practice and clinical interventional trials.

Elevated ornithine decarboxylase activity promotes skin tumorigenesis by stimulating the recruitment of bulge stem cells but not via toxic polyamine catabolic metabolites.

Elevated expression of ornithine decarboxylase (ODC), the regulatory enzyme in polyamine biosynthesis, targeted to the epidermis is sufficient to promote skin tumor development following a single subthreshold dose of dimethylbenz(a)anthracene (DMBA). Since skin tumor promotion involves recruitment of hair follicle bulge stem cells harboring genetic lesions, we assessed the effect of increased epidermal ODC on recruitment of bulge stem cells in ODC-ER transgenic mice in which ODC activity is induced de novo in adult skin with 4-hydroxytamoxifen (4OHT). Bromodeoxyuridine-pulse labeling and use of K15.CrePR1;R26R;ODC-ER triple transgenic mice demonstrated that induction of ODC activity is sufficient to recruit bulge stem cells in quiescent skin. Because increased ODC activity not only stimulates proliferation but also increases reactive oxygen species (ROS) generation via subsequent induction of polyamine catabolic oxidases, we used an inhibitor of polyamine catabolic oxidase activity, MDL72527, to investigate whether ROS generation by polyamine catabolic oxidases contributes to skin tumorigenesis in DMBA-initiated ODC-ER transgenic skin. Newborn ODC-ER transgenic mice and their normal littermates were initiated with a single topical dose of DMBA. To assess tumor development originating from dormant bulge stem cells that possess DMBA-initiated mutations, epidermal ODC activity was induced in ODC-ER mice with 4OHT 5 weeks after DMBA initiation followed by MDL72527 treatment. MDL72527 treatment resulted in a shorter tumor latency time, increased tumor burden, increased conversion to carcinomas, and lower tumor levels of p53. Thus, elevated epidermal ODC activity promotes tumorigenesis by stimulating the recruitment of bulge stem cells but not via ROS generation by polyamine catabolic oxidases.

Maralixibat in progressive familial intrahepatic cholestasis (MARCH-PFIC): a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: Progressive familial intrahepatic cholestasis (PFIC) is a group of autosomal recessive disorders, the most prevalent being BSEP deficiency, resulting in disrupted bile formation, cholestasis, and pruritus. Building on a previous phase 2 study, we aimed to evaluate the efficacy and safety of maralixibat-an ileal bile acid transporter inhibitor-in participants with all types of PFIC. METHODS: MARCH-PFIC was a multicentre, randomised, double-blind, placebo-controlled, phase 3 study conducted in 29 community and hospital centres across 16 countries in Europe, the Americas, and Asia. We recruited participants aged 1-17 years with PFIC with persistent pruritus (>6 months; average of ≥1·5 on morning Itch-Reported Outcome [Observer; ItchRO(Obs)] during the last 4 weeks of screening) and biochemical abnormalities or pathological evidence of progressive liver disease, or both. We defined three analysis cohorts. The BSEP (or primary) cohort included only those with biallelic, non-truncated BSEP deficiency without low or fluctuating serum bile acids or previous biliary surgery. The all-PFIC cohort combined the BSEP cohort with participants with biallelic FIC1, MDR3, TJP2, or MYO5B deficiencies without previous surgery but regardless of bile acids. The full cohort had no exclusions. Participants were randomly assigned (1:1) to receive oral maralixibat (starting dose 142·5 µg/kg, then escalated to 570 µg/kg) or placebo twice daily for 26 weeks. The primary endpoint was the mean change in average morning ItchRO(Obs) severity score between baseline and weeks 15-26 in the BSEP cohort. The key secondary efficacy endpoint was the mean change in total serum bile acids between baseline and the average of weeks 18, 22, and 26 in the BSEP cohort. Efficacy analyses were done in the intention-to-treat population (all those randomly assigned) and safety analyses were done in all participants who received at least one dose of study drug. This completed trial is registered with ClinicalTrials.gov, NCT03905330, and EudraCT, 2019-001211-22. FINDINGS: Between July 9, 2019, and March 4, 2022, 125 patients were screened, of whom 93 were randomly assigned to maralixibat (n=47; 14 in the BSEP cohort and 33 in the all-PFIC cohort) or placebo (n=46; 17 in the BSEP cohort and 31 in the all-PFIC cohort), received at least one dose of study drug, and were included in the intention-to-treat and safety populations. The median age was 3·0 years (IQR 2·0-7·0) and 51 (55%) of 93 participants were female and 42 (45%) were male. In the BSEP cohort, least-squares mean change from baseline in morning ItchRO(Obs) was -1·7 (95% CI -2·3 to -1·2) with maralixibat versus -0·6 (-1·1 to -0·1) with placebo, with a significant between-group difference of -1·1 (95% CI -1·8 to -0·3; p=0·0063). Least-squares mean change from baseline in total serum bile acids was -176 µmol/L (95% CI -257 to -94) for maralixibat versus 11 µmol/L (-58 to 80) for placebo, also representing a significant difference of -187 µmol/L (95% CI -293 to -80; p=0·0013). The most common adverse event was diarrhoea (27 [57%] of 47 patients on maralixibat vs nine [20%] of 46 patients on placebo; all mild or moderate and mostly transient). There were five (11%) participants with serious treatment-emergent adverse events in the maralixibat group versus three (7%) in the placebo group. No treatment-related deaths occurred. INTERPRETATION: Maralixibat improved pruritus and predictors of native liver survival in PFIC (eg, serum bile acids). Maralixibat represents a non-surgical, pharmacological option to interrupt the enterohepatic circulation and improve the standard of care in patients with PFIC. FUNDING: Mirum Pharmaceuticals.

Neurocognitive outcomes at kindergarten entry after liver transplantation at <3 yr of age.

This prospective inception cohort study determines kindergarten-entry neurocognitive abilities and explores their predictors following liver transplantation at age <3 yr. Of 52 children transplanted (1999-2008), 33 (89.2%) of 37 eligible survivors had psychological assessment at age 54.7 (8.4) months: 21 with biliary atresia, seven chronic cholestasis, and five acute liver failure. Neurocognitive scores (mean [s.d.], 100 [15]) as tested by a pediatric-experienced psychologist did not differ in relation to age group at transplant (≤12 months and >12 months): FSIQ, 93.9 (17.1); verbal (VIQ), 95.3 (16.5); performance (PIQ), 94.3 (18.1); and VMI, 90.5 (15.9), with >70% having scores ≥85, average or above. Adverse predictors from the pretransplant, transplant, and post-transplant (30 days) periods using univariate linear regressions for FSIQ were post-transplant use of inotropes, p = 0.029; longer transplant warm ischemia time, p = 0.035; and post-transplant highest serum creatinine, (p = 0.04). For PIQ, they were pretransplant encephalopathy, p = 0.027; post-transplant highest serum creatinine, p = 0.034; and post-transplant inotrope use, p = 0.037. For VMI, they were number of post-transplant infections, p = 0.019; post-transplant highest serum creatinine, p = 0.025; and lower family socioeconomic index, p = 0.039. Changes in care addressing modifiable predictors, including reducing acute post-transplant illness, pretransplant encephalopathy, transplant warm ischemia times, and preserving renal function, may improve neurocognitive outcomes.

Rebalancing polyamine levels to treat Snyder-Robinson syndrome.

Snyder-Robinson syndrome (SRS) is a rare genetic disorder characterized by intellectual disability and delayed development beginning early in childhood. It was first described in a single family in 1969 as a sex-linked disorder (Snyder & Robinson, 1969) and has since been only identified in less than 100 individuals worldwide. Inherited in an X-linked recessive pattern, SRS has only been identified in males thus far. Snyder-Robinson syndrome primarily affects the nervous system and skeletal tissues and is caused by loss-of-function mutations in the gene encoding spermine synthase (SMS), a polyamine biosynthesis enzyme. Affected males display a collection of clinical features including intellectual disability ranging from mild to profound, speech and vision impairment, osteoporosis, hypotonia, and increasing loss of muscle tissue with age, kyphoscoliosis, seizures, and distinctive facial features including a prominent lower lip and facial asymmetry. Currently, there is no cure or treatment for this debilitating disorder aside from symptom management.