Gut Analysis Toolbox: Automating quantitative analysis of enteric neurons.

The enteric nervous system (ENS) consists of an extensive network of neurons and glial cells embedded within the wall of the gastrointestinal (GI) tract. Alterations in neuronal distribution and function are strongly associated with GI dysfunction. Current methods for assessing neuronal distribution suffer from undersampling, partly due to challenges associated with imaging and analyzing large tissue areas, and operator bias due to manual analysis. We present the Gut Analysis Toolbox (GAT), an image analysis tool designed for characterization of enteric neurons and their neurochemical coding using 2D images of GI wholemount preparations. It is developed in Fiji, has a user-friendly interface and offers rapid and accurate segmentation via custom deep learning (DL) based cell segmentation models developed using StarDist, and a ganglion segmentation model in deepImageJ. We use proximal neighbor-based spatial analysis to reveal differences in cellular distribution across gut regions using a public dataset. In summary, GAT provides an easy-to-use toolbox to streamline routine image analysis tasks in ENS research. GAT enhances throughput allowing unbiased analysis of larger tissue areas, multiple neuronal markers and numerous samples rapidly.

Anorectal Malformation Patients in Australia and Europe: Different Location, Same Problem? A Retrospective Comparative Registry-based Study.

Anorectal malformations (ARM) encompass a spectrum of rare congenital defects of the rectum and anus, requiring specialized reconstructive surgery. To improve epidemiological and clinical research in rare diseases such as ARM, collaborative efforts and patient registries are key. This retrospective study pools clinical data over a 30-year period from two ARM patient registries (The Royal Children's Hospital (RCH) in Melbourne, Australia, and the ARM-Network Consortium in Europe). It aims to draw comparisons on demographics, management, and outcomes between ARM patients in Australia and Europe. A total of 2947 ARM patients were included in the analyses. The RCH cohort had more complex ARM types (including rectal atresia and recto-vaginal fistula) and more associated anomalies, specifically skeletal, cardiac, and/or trachea-esophageal, than ARM-Net patients. Other patient characteristics were similar. Treatments clearly differed between the groups. European surgeons favoured the PSARP approach for both less complex and more complex ARM types, where Australian surgeons opted more often for cutback surgery in less complex, and laparoscopic assistance in more complex types. Complications were differently distributed, with less complications after LAARP and more after PSARP at RCH, compared to ARM-Net. While RCH patients more often required a redo, ARM-Net patients more commonly underwent anal dilatations. Anorectal malformation patients in Australia and Europe had minor differences in disease characteristics, and both operative and medical approaches differed. Joint efforts such as the present study emphasize the importance of collaboration to elucidate areas of improvement where surgeons may learn from each other across the world, ultimately improving patient outcomes. TYPE OF STUDY: Original Research. LEVEL OF EVIDENCE: III.

Utility of ligamentum teres hepatis flap reinforcement to prevent postoperative pancreatic fistulas in robotic distal pancreatectomy.

BACKGROUND: Postoperative pancreatic fistula (POPF) is a significant contributor to morbidity and mortality after robotic distal pancreatectomy (RDP). Ligamentum teres hepatis (LTH) reinforcement of the pancreatic remnant may reduce the incidence of POPF. METHODS: Patients ≥18 years old, who underwent RDP at the University of Massachusetts Memorial Medical Center from 01/01/2018-08/31/2022. Primary endpoint was POPF incidence. Secondary outcomes included peri- and postoperative variables. RESULTS: Thirty-three patients underwent RDP, of which LTH reinforcement was used in 21 (64 â€‹%) cases. Six (18 â€‹%) patients developed a POPF. No association was identified between LTH flap reinforcement and POPF (OR 1.18, 95 â€‹% CI 0.18 to 7.85, p â€‹= â€‹0.87). There were no peri- or postoperative complications related to ligamentum teres flap creation. CONCLUSIONS: LTH reinforcement of the pancreatic remnant can be safely performed during RDP. Further studies are needed to assess the utility of this intervention to mitigate the risk of pancreatic fistula formation following RDP.

A Novel Use of Embryonic Gut Organoid Culture to Investigate Duodenal Atresia.

BACKGROUND: The cause of duodenal atresia (DA) is not known. Tandler's "solid cord" hypothesis conflicts with current biological evidence. In humans, a genetic aetiology is supported by the association with Trisomy 21. Interruption of Fgf10 is the strongest genetic link to DA in mice, demonstrating an increased incidence and severity as embryos mature. This project aimed to develop an organoid model to facilitate ex vivo DA research on the FGF10/FGFR2b signalling pathway. We hypothesised that DA morphology represents an evolving spectrum of disease and that Fgf10 knockout organoids would vary in growth pattern compared to wild-type. METHODS: Organoids were cultured from the duodenum of E12.5 Fgf10 knockout, heterozygous and wild-type embryos, using an air-liquid interface with Growth Factor reduced Matrigel. Organoids were photographed every 48 h to observe growth. Organoids were isolated and fixed after 14 days, then stained with DAPI, KI-67, and cytokeratin to demonstrate proliferation and differentiation. RESULTS: Wild-type duodenum developed into crypt-forming organoids. Fgf10 heterozygous duodenum failed to progress beyond the development stage of spheroids. Fgf10 knockout duodenum failed to demonstrate any growth. Wholemount staining showed the greatest cell proliferation and differentiation in wild-type tissue. CONCLUSION: This research presents a novel concept for the growth of embryonic gastrointestinal tissue to inform normal biology. The small sample numbers and restricted culture duration limit longer-term growth analysis. While this model serves as a potential ex vivo setting for future research, that research should consider organoid models with greater standardisation and other gastrointestinal regions. LEVEL OF EVIDENCE: Animal/laboratory study.

Hereditary Transthyretin Amyloidosis (hATTR) with Polyneuropathy Clusters Are Located in Ancient Mining Districts: A Possible Geochemical Origin of the Disease.

Hereditary transthyretin amyloidosis (hATTR) with polyneuropathy (formerly known as Familial Amyloid Polyneuropathy (FAP)) is an endemic amyloidosis involving the harmful aggregation of proteins, most commonly transthyretin (TTR) but sometimes also apolipoprotein A-1 or gelsolin. hATTR appears to be transmitted as an autosomal dominant trait. Over 100 point mutations have been identified, with the Val30Met substitution being the most common. Yet, the mechanism of pathogenesis and the overall origin of hATTR remain unclear. Here, we argue that hATTR could be related to harmful metal exposure. hATTR incidence is unevenly distributed globally, and the three largest defined clusters exist in Japan, Portugal, and Sweden. All three disease regions are also ancient mining districts with associated metal contamination of the local environment. There are two main mechanisms for how harmful metals, after uptake into tissues and body fluids, could induce hATTR. First, the metals could directly influence the expression, function, and/or aggregation of the proteins involved in hATTR pathology. Such metal-protein interactions might constitute molecular targets for anti-hATTR drug design. Second, metal exposure could induce hATTR -associated genetic mutations, which may have happened several generations ago. These two mechanisms can occur in parallel. In conclusion, the possibility that hATTR could be related to metal exposure in geochemically defined regions deserves further attention.

Temporal trend of first-line drug choice and treatment continuity for hypertension among citizens 75 years or over - a register-based, cohort study.

BACKGROUND: Limited knowledge of antihypertensive treatment of the elderly potentially impedes effective strategies for hypertension management in this growing patient group. We aimed to investigate temporal trends for first-line drug choice for antihypertensive treatment and treatment continuity among patients ≥75 years from 2000 to 2021. METHODS: Using nationwide Danish registers, patients ≥75 years initiated for the first time on antihypertensive drugs: Angiotensin converting enzyme inhibitors (ACEi), angiotensin II receptor blockers (ARB), beta blockers (BB), calcium channel blockers (CCB), thiazides, or combinations, were identified. Patients with other indications than hypertension were excluded. Treatment continuity was described using claimed prescriptions the first 180 days following study entry. RESULTS: From 2000 to 2021, 170,769 patients (median age 80 years [interquartile range:77-84], 60.3% female) were included. From 2000 to 2003 to 2015-2021 the proportion of first-line drug choice increased for ACEi (8.7% to 14.9%), ARB (4.1% to 23.9%), and CCB (10.7% to 27.6%), decreased for thiazides (60.6% to 15.9%) and remained stable for BB (12.9% to 14.1%) and combinations (2.9% to 3.6%). For 157,457 patients alive after 180 days, discontinuation was highest among patients initiated on thiazides (28.3%) whereas most patients continued the same single drug regimen if they started on ACEi (55.2%), ARB (65.0%), BB (57.2%) or CCB (59.3%). CONCLUSIONS: From 2000 to 2021 thiazides have been replaced by ACEi, ARB and CCB. Thiazides had the lowest treatment continuity while ARB appeared preferred slightly over ACEi. Differences in adherence in relation to first-line drug choice may warrant scrutiny regarding recommendations for the elderly.

Impact of breast-, gastrointestinal-, and lung cancer on prognosis in patients with first-time pulmonary embolism: A Danish nationwide cohort study.

BACKGROUND: Pulmonary embolism (PE) is described as a prognostic factor in patients with cancer however, the prognostic impact of PE remains unknown. This study investigated, the 1-year prognosis following PE in patients with breast-, gastrointestinal-, or lung cancer stratified by cancer status. METHODS: All Danish patients with first-time PE from 2008 to 2018 were included. Cancer status was categorized as no cancer, history of cancer, non-active cancer and active cancer. Unadjusted and age-stratified 1-year risk of death was estimated using the Kaplan-Meier estimator. Cause of death was reported using the Aalen-Johansen method. RESULTS: Of 35,679 patients with PE, 18% had a breast-, gastrointestinal-, or lung cancer. Patients with cancer were older compared with no cancer (69.8 years [IQR: 56.2-79.8]). One-year risk of death (95% confidence interval) for active breast-, gastrointestinal-, and lung cancer was 49.5% (44.0%-54.9%), 75.0% (72.5%-77.4%) and 80.1% (78.0%-82.3%) respectively, compared with 18.9% (18.4%-19.3%) for no cancer. Age-stratified analysis revealed no association with increasing age in non-active lung cancer and all active cancers. Further, non-cardiovascular death accounted for an increasing proportion by cancer status (no cancer < history of cancer < non-active cancer < active cancer). CONCLUSIONS: One-year risk of death was dependent on both cancer type and status; no association with age was found for patients with active cancers. Non-cardiovascular death was leading in non-active and active cancers. Thus, the occurrence of first-time PE could be regarded as a marker of cancer severity for patients with breast-, gastrointestinal-, and lung cancer.

Esophago-gastric junction findings on high resolution impedance manometry in children with esophageal atresia.

OBJECTIVES: Using high resolution impedance manometry (HRIM), this study characterized the esophago-gastric junction (EGJ) dynamics in children with esophageal atresia (EA). METHOD: Esophageal HRIM was performed in patients with EA aged less than 18 years. Objective motility patterns were analyzed, and EGJ data reported. Controls were pediatric patients without EA undergoing investigations for consideration of fundoplication surgery. RESULTS: Seventy-five patients (M:F = 43:32, median age 1 year 3 months [3 months-17 years 4 months]) completed 133 HRIM studies. The majority (64/75, 85.3%) had EA with distal tracheo-esophageal fistula. Compared with controls, liquid swallows were poorer in patients with EA, as evident by significant differences in distension pressure emptying and bolus flow time (BFT). The integrated relaxation pressure for thin liquid swallows was significantly different between EA types, as well as when comparing patients with EA with and without previous esophageal dilatations. The BFT for solid swallows was significantly different when compared with EA types. CONCLUSIONS: We have utilized HRIM in patients with EA to demonstrate abnormalities in their long-term EGJ function. These abnormalities correlate with poorer esophageal compliance and reduced esophageal peristalsis across the EGJ. Understanding the EGJ function in patients with EA will allow us to tailor long-term management to specific patients.

Transition From Pediatric to Adult Healthcare for Colorectal Conditions: A Systematic Review.

BACKGROUND: Despite surgical advances for complex congenital colorectal conditions, such as anorectal malformation (ARM) and Hirschsprung disease (HD), many adolescents require transfer from specialist pediatric to adult providers for ongoing care. METHODOLOGY: A systematic review of PubMed, MEDLINE and Embase was conducted to identify what is known about the transitional care of patients with ARM and HD (PROSPERO # CRD42022281558). The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework guided our reporting of studies that focused on the transition care of 10-30-year-olds with ARM and HD. RESULTS: Eight studies were identified that included patient and parent (n = 188), and/or clinician perspectives (n = 334). Patients and clinicians agreed that transitional care should commence early in adolescence to support transfer to adult care when a suitable level of maturation is reached. There was little evidence from patients that transfer happened in a timely or coordinated manner. Patients felt that clinicians did not always understand the significance of transfer to adult services. No models of transition care were identified. Surgeons ranked ARM and HD as the most common conditions to experience delayed transfer to adult care. Beyond pediatric surgeons, patients also highlighted the importance of general practitioners, transitional care coordinators and peer support groups for successful transition. CONCLUSIONS: There is little research focused on transitional care for patients with ARM and HD. Given evidence of delayed transfer and poor experiences, the development of models of transitional care appears essential.

TRPV4 is expressed by enteric glia and muscularis macrophages of the colon but does not play a prominent role in colonic motility.

Background: Mechanosensation is an important trigger of physiological processes in the gastrointestinal tract. Aberrant responses to mechanical input are associated with digestive disorders, including visceral hypersensitivity. Transient Receptor Potential Vanilloid 4 (TRPV4) is a mechanosensory ion channel with proposed roles in visceral afferent signaling, intestinal inflammation, and gut motility. While TRPV4 is a potential therapeutic target for digestive disease, current mechanistic understanding of how TRPV4 may influence gut function is limited by inconsistent reports of TRPV4 expression and distribution. Methods: In this study we profiled functional expression of TRPV4 using Ca2+ imaging of wholemount preparations of the mouse, monkey, and human intestine in combination with immunofluorescent labeling for established cellular markers. The involvement of TRPV4 in colonic motility was assessed in vitro using videomapping and contraction assays. Results: The TRPV4 agonist GSK1016790A evoked Ca2+ signaling in muscularis macrophages, enteric glia, and endothelial cells. TRPV4 specificity was confirmed using TRPV4 KO mouse tissue or antagonist pre-treatment. Calcium responses were not detected in other cell types required for neuromuscular signaling including enteric neurons, interstitial cells of Cajal, PDGFRα+ cells, and intestinal smooth muscle. TRPV4 activation led to rapid Ca2+ responses by a subpopulation of glial cells, followed by sustained Ca2+ signaling throughout the enteric glial network. Propagation of these waves was suppressed by inhibition of gap junctions or Ca2+ release from intracellular stores. Coordinated glial signaling in response to GSK1016790A was also disrupted in acute TNBS colitis. The involvement of TRPV4 in the initiation and propagation of colonic motility patterns was examined in vitro. Conclusions: We reveal a previously unappreciated role for TRPV4 in the initiation of distension-evoked colonic motility. These observations provide new insights into the functional role of TRPV4 activation in the gut, with important implications for how TRPV4 may influence critical processes including inflammatory signaling and motility.

Psychosocial Outcomes of Parents of Children with Hirschsprung Disease Beyond Early Childhood.

PURPOSE: The lifelong impact of Hirschsprung disease (HD) upon children and their families is increasingly well recognized. Parental psychosocial wellbeing and family functioning are determinants of psychological and health-related outcomes in children with chronic conditions. We performed a cross-sectional cohort study to evaluate the psychosocial functioning of parents/caregivers of children with HD, beyond early childhood. METHODS: Parents/caregivers of children with HD, aged 4-14 years, managed at a tertiary pediatric surgical center were surveyed. Parent psychosocial outcomes, including adjustment to illness and family response, were assessed using four validated measures: Family Management Measure (FaMM); Parent Experience of Child Illness (PECI); Patient Reported Outcomes Measurement Information System (PROMISR) anxiety; and PROMISR depression. The Pediatric Quality of Life Inventory (PedsQL) was administered to assess child quality of life (proxy-report). RESULTS: Forty parents (mean age 38.7 ± 5.6 years) of children with HD (mean age 8.0 ± 2.5) participated. Parents expressed greater long-term uncertainty (PECI) and poorer perceived condition management ability (FaMM) than comparator chronic disease cohorts. Other scores for parental adjustment to their child's condition (PECI) and family response (FaMM) were comparable to reference cohorts. Symptoms of anxiety and depression were prevalent in our cohort (52.5 % and 42.5 % respectively); however, the proportion with moderate - severe PROMISR anxiety (χ2 = 2.50, p = 0.114) and depression (χ2 = 0.156, p = 0.693) scores did not significantly differ from the expected population distribution. Proxy-reported child quality of life (PedsQL) was significantly reduced relative to healthy children (p = 0.0003), but comparable to those with physical health problems with special healthcare needs (p = 0.624). CONCLUSIONS: Parents of children with HD experience long-term uncertainty and have poorer perceived condition management ability than parents of children with other chronic childhood illnesses. This work highlights the importance of targeted parental education and support beyond primary surgical management, and provides a benchmark for this cohort, against which subsequent intervention-based studies may be assessed. LEVEL OF EVIDENCE: II.

Direct Competition of ATCUN Peptides with Human Serum Albumin for Copper(II) Ions Determined by LC-ICP MS.

Copper is an indispensable biometal, primarily serving as a redox-competent cofactor in numerous proteins. Apart from preformed copper-binding sites within the protein structures, small peptide motifs exist called ATCUN, which are composed of an N-terminal tripeptide XZH, able to bind Cu(II) ions in exchangeable form. These motifs are common for serum albumin, but they are also present in a wide range of proteins and peptides. These proteins and peptides can be involved in copper metabolism, and copper ions can affect their biological role. The distribution of copper between the ATCUN peptides, including truncated amyloid-ß (Aß) peptides Aß4-42 and Aß11-42, which may be involved in Alzheimer's disease pathogenesis, is mainly determined by their concentrations and relative Cu(II)-binding affinities. The Cu(II)-binding affinity (log Kd) of several ATCUN peptides, determined by different methods and authors, varies by more than three orders of magnitude. This variation may be attributed to the chemical properties of peptides but can also be influenced by the differences in methods and experimental conditions used for the determination of Kd. In the current study, we performed direct competition experiments between selected ATCUN peptides and HSA by using an LC-ICP MS-based approach. We demonstrated that ATCUN and truncated Aß peptides Aß4-16 and Aß11-15 bind Cu(II) ions with an affinity similar to that for HSA. Our results demonstrate that ATCUN motifs cannot compete with excess HSA for the binding of Cu(II) ions in the blood and cerebrospinal fluid.

Evans syndrome caused by a deleterious mutation affecting the adaptor protein SASH3.

Increasing evidence suggests multilineage cytopenias (also known as Evans syndrome) may be caused by inborn errors of immunity (IEI) with immune dysregulation. We studied a patient with autoimmune haemolytic anaemia and immune thrombocytopenia and identified a germline mutation in SASH3 (c.862C>T;p.Arg288Ter), indicating a recently identified IEI. Immunohistochemistry performed after clinically indicated splenectomy revealed severe hypoplasia/absence of germinal centres. The autoimmune phenotype was associated with an increased CD21low T-bet+ CD11c+ subset along with decreased regulatory T cells, impaired T-cell proliferation and T-cell exhaustion. The younger brother carries the same SASH3 mutation and shares immunophenotypic features but is currently clinical asymptomatic, indicating heterogeneity of SASH3 deficiency.

13C- and 15N-labeling of amyloid-ß and inhibitory peptides to study their interaction via nanoscale infrared spectroscopy.

Interactions between molecules are fundamental in biology. They occur also between amyloidogenic peptides or proteins that are associated with different amyloid diseases, which makes it important to study the mutual influence of two polypeptides on each other's properties in mixed samples. However, addressing this research question with imaging techniques faces the challenge to distinguish different polypeptides without adding artificial probes for detection. Here, we show that nanoscale infrared spectroscopy in combination with 13C, 15N-labeling solves this problem. We studied aggregated amyloid-ß peptide (Aß) and its interaction with an inhibitory peptide (NCAM1-PrP) using scattering-type scanning near-field optical microscopy. Although having similar secondary structure, labeled and unlabeled peptides could be distinguished by comparing optical phase images taken at wavenumbers characteristic for either the labeled or the unlabeled peptide. NCAM1-PrP seems to be able to associate with or to dissolve existing Aß fibrils because pure Aß fibrils were not detected after mixing.

Patient mortality following new-onset heart failure stratified by cancer type and status.

AIM: Expected 1-year survival is essential to risk stratification of patients with heart failure (HF); however, little is known about the 1-year prognosis of patients with HF and cancer. Thus, the objective was to investigate the 1-year prognosis following new-onset HF stratified by cancer status in patients with breast, gastrointestinal, or lung cancer. METHODS AND RESULTS: All Danish patients with new-onset HF from 2000 to 2018 were included. Cancer status was categorized as history of cancer (no cancer-related contact within 5 years of HF diagnosis), non-active cancer (curative intended procedure administered) and active cancer. Standardized 1-year all-cause mortality was reported using G-computation. Age-stratified 1-year all-cause mortality was estimated using the Kaplan-Meier estimator. In total, 193 359 patients with HF were included, 7.3% had either a breast, gastrointestinal, or lung cancer diagnosis. Patients with cancer were older and more comorbid than patients without cancer. Standardized 1-year all-cause mortality (95% confidence intervals) was 24.6% (23.0-26.2%), 27.1% (25.5-28.6%), and 29.9% (25.9-34.0%) for history of breast, gastrointestinal and lung cancer, respectively, which was comparable to patients with non-active cancers. For active breast, gastrointestinal and lung cancer, standardized 1-year all-cause mortality was 36.2% (33.8-38.6%), 49.0% (47.2-50.9%), and 61.6% (59.7-63.5%), respectively. One-year all-cause mortality increased incrementally with age, except for active lung cancer. CONCLUSION: Standardized 1-year all-cause mortality was comparable for patients with history of cancer and non-active cancer regardless of cancer type, but varied comprehensively for active cancers. Prognostic impact of age was limited for active lung cancer. Thus, granular stratification of cancer is necessary for optimized management of new-onset HF.

Characterization of Uranyl (UO22+) Ion Binding to Amyloid Beta (Aß) Peptides: Effects on Aß Structure and Aggregation.

Uranium (U) is naturally present in ambient air, water, and soil, and depleted uranium (DU) is released into the environment via industrial and military activities. While the radiological damage from U is rather well understood, less is known about the chemical damage mechanisms, which dominate in DU. Heavy metal exposure is associated with numerous health conditions, including Alzheimer's disease (AD), the most prevalent age-related cause of dementia. The pathological hallmark of AD is the deposition of amyloid plaques, consisting mainly of amyloid-ß (Aß) peptides aggregated into amyloid fibrils in the brain. However, the toxic species in AD are likely oligomeric Aß aggregates. Exposure to heavy metals such as Cd, Hg, Mn, and Pb is known to increase Aß production, and these metals bind to Aß peptides and modulate their aggregation. The possible effects of U in AD pathology have been sparsely studied. Here, we use biophysical techniques to study in vitro interactions between Aß peptides and uranyl ions, UO22+, of DU. We show for the first time that uranyl ions bind to Aß peptides with affinities in the micromolar range, induce structural changes in Aß monomers and oligomers, and inhibit Aß fibrillization. This suggests a possible link between AD and U exposure, which could be further explored by cell, animal, and epidemiological studies. General toxic mechanisms of uranyl ions could be modulation of protein folding, misfolding, and aggregation.

The early years: hirschsprung disease and health-related quality of life.

PURPOSE: Chronic diseases are notorious in the way that they interfere with many aspects of a child's development, and this holds true for children with Hirschsprung disease (HD). The present research aims to (1) determine whether the health-related quality of life (HRQoL) of HD children differs from healthy paediatric populations; and (2) explore the relationship between HD children's HRQoL and psychosocial outcomes of parents. METHODS: Using a cross-sectional survey study design, children's HRQoL was assessed using the Pediatric Quality of Life Inventory (PedsQL), while parental psychosocial outcomes were measured using the Patient-Reported Outcomes Measurement Information System (PROMIS) anxiety and depression short-forms, Family Management Measure (FaMM), and Parent Experience of Child Illness. Surveys were administered over telephone to parents of 48 Australian children treated for HD (87.5% male, median age 4.5 years) during the period May to November 2021. RESULTS: While postoperative HRQoL of HD children was comparable to that of healthy age-matched controls, psychosocial quality of life of HD children was significantly poorer (mean difference = 3.40, CI [0.05, 6.76]). All parental outcome measures were significantly correlated with the PedsQL (r = - 0.77-0.67, p < 0.05) in expected directions, with FaMM subscales (except parent mutuality) demonstrating the most variation (R2 = 0.41-0.59). Of note, 31.3% of parents reported moderate to severe symptoms of anxiety on the PROMIS. CONCLUSION: Despite overall positive results for children, parents reported elevated symptoms of anxiety. This study highlights the importance of long-term follow-up care for HD patients and their families.

Efficacy of HER2-Targeted Intraperitoneal 225Ac α-Pretargeted Radioimmunotherapy for Small-Volume Ovarian Peritoneal Carcinomatosis.

Epithelial ovarian cancer (EOC) is often asymptomatic and presents clinically in an advanced stage as widespread peritoneal microscopic disease that is generally considered to be surgically incurable. Targeted α-therapy with the α-particle-emitting radionuclide 225Ac (half-life, 9.92 d) is a high-linear-energy-transfer treatment approach effective for small-volume disease and even single cells. Here, we report the use of human epidermal growth factor receptor 2 (HER2) 225Ac-pretargeted radioimmunotherapy (PRIT) to treat a mouse model of human EOC SKOV3 xenografts growing as peritoneal carcinomatosis (PC). Methods: On day 0, 105 SKOV3 cells transduced with a luciferase reporter gene were implanted intraperitoneally in nude mice, and tumor engraftment was verified by bioluminescent imaging (BLI). On day 15, treatment was started using 1 or 2 cycles of 3-step anti-HER2 225Ac-PRIT (37 kBq/cycle as 225Ac-Proteus DOTA), separated by a 1-wk interval. Efficacy and toxicity were monitored for up to 154 d. Results: Untreated PC-tumor-bearing nude mice showed a median survival of 112 d. We used 2 independent measures of response to evaluate the efficacy of 225Ac-PRIT. First, a greater proportion of the treated mice (9/10 1-cycle and 8/10 2-cycle; total, 17/20; 85%) survived long-term compared with controls (9/27, 33%), and significantly prolonged survival was documented (log-rank [Mantel-Cox] P = 0.0042). Second, using BLI, a significant difference in the integrated BLI signal area to 98 d was noted between controls and treated groups (P = 0.0354). Of a total of 8 mice from the 2-cycle treatment group (74 kBq total) that were evaluated by necropsy, kidney radiotoxicity was mild and did not manifest itself clinically (normal serum blood urea nitrogen and creatinine). Dosimetry estimates (relative biological effectiveness-weighted dose, where relative biological effectiveness = 5) per 37 kBq administered for tumors and kidneys were 56.9 and 16.1 Gy, respectively. One-cycle and 2-cycle treatments were equally effective. With immunohistology, mild tubular changes attributable to α-toxicity were observed in both therapeutic groups. Conclusion: Treatment of EOC PC-tumor-bearing mice with anti-HER2 225Ac-PRIT resulted in histologic cures and prolonged survival with minimal toxicity. Targeted α-therapy using the anti-HER2 225Ac-PRIT system is a potential treatment for otherwise incurable EOC.