Neurofibromatosis type 1-related pseudarthrosis: Beyond the pseudarthrosis site.

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder affecting approximately 1 in 2,000 newborns. Up to 5% of NF1 patients suffer from pseudarthrosis of a long bone (NF1-PA). Current treatments are often unsatisfactory, potentially leading to amputation. To gain more insight into the pathogenesis we cultured cells from PA tissue and normal-appearing periosteum of the affected bone for NF1 mutation analysis. PA cells were available from 13 individuals with NF1. Biallelic NF1 inactivation was identified in all investigated PA cells obtained during the first surgery. Three of five cases sampled during a later intervention showed biallelic NF1 inactivation. Also, in three individuals, we examined periosteum-derived cells from normal-appearing periosteum proximal and distal to the PA. We identified the same biallelic NF1 inactivation in the periosteal cells outside the PA region. These results indicate that NF1 inactivation is required but not sufficient for the development of NF1-PA. We observed that late-onset NF1-PA occurs and is not always preceded by congenital bowing. Furthermore, the failure to identify biallelic inactivation in two of five later interventions and one reintervention with a known somatic mutation indicates that NF1-PA can persist after the removal of most NF1 negative cells

Reports paper Risk_Benefit Orally Bioavailable Flubendazole Formulation

reports containing full description of methods and all data of toxicity studies and pharmacokinetic studies described in the pape

Data from: Preclinical toxicity and pharmacokinetics of a new orally bioavailable flubendazole formulation and the impact for clinical trials and risk/benefit to patients.

Background: Flubendazole, originally developed to treat infections with intestinal nematodes, has been shown to be efficacious in animal models of filarial infections. For treatment of filarial nematodes, systemic exposure is needed. For this purpose, an orally bioavailable amorphous solid dispersion (ASD) formulation was developed. As this formulation results in improved systemic absorption, the pharmacokinetic and toxicological profile of flubendazole administered with this formulation have been assessed to ensure human safety before clinical trials could be initiated. Methods & Findings: Safety pharmacology, toxicity and genotoxicity studies have been conducted with the flubendazole ASD formulation. In animals, flubendazole has good oral bioavailability from an ASD formulation ranging from 15 % in dogs, 276 % in rats to more than 100% in jirds. In in vivo toxicity studies with the ASD formulation, high systemic exposure to flubendazole and its main metabolites was reached. Flubendazole, up to high peak plasma concentrations, does not induce Cmax related effects in the CNS or cardiovascular system. In repeated dose toxicity studies in rats and dogs, flubendazole-induced changes were observed in haematological, lymphoid and gastrointestinal systems and in testes. In dog, the liver was an additional target organ. Upon treatment cessation, at least partial recovery was observed for these changes in the dog. In rat, the low dose was the No Observed Adverse Effect Level (NOAEL) was , i.e. 5 mg (as base)/kg body weight/day (mg eq./kg/day)mg eq./kg/day in males and 2.5 mg eq./kg/day in females. In dog, the NOAEL was lower than the low dose, 20 mg eq./kg/day. Regarding genotoxicity, flubendazole was negative in the Ames test but positive in the in vivo micronucleus test. Conclusions: Based on these results, in combination with previously described genotoxicity and reproductive toxicity data and the outcome of the preclinical efficacy studies, it was concluded that no flubendazole treatment regimen can be selected that would provide efficacy in humans at safe exposure

Preclinical toxicity and pharmacokinetics of a new orally bioavailable flubendazole formulation and the impact for clinical trials and risk/benefit to patients.

BackgroundFlubendazole, originally developed to treat infections with intestinal nematodes, has been shown to be efficacious in animal models of filarial infections. For treatment of filarial nematodes, systemic exposure is needed. For this purpose, an orally bioavailable amorphous solid dispersion (ASD) formulation of flubendazole was developed. As this formulation results in improved systemic absorption, the pharmacokinetic and toxicological profile of the flubendazole ASD formulation have been assessed to ensure human safety before clinical trials could be initiated.Methods & findingsSafety pharmacology, toxicity and genotoxicity studies have been conducted with the flubendazole ASD formulation. In animals, flubendazole has good oral bioavailability from an ASD formulation ranging from 15% in dogs, 27% in rats to more than 100% in jirds. In in vivo toxicity studies with the ASD formulation, high systemic exposure to flubendazole and its main metabolites was reached. Flubendazole, up to high peak plasma concentrations, does not induce Cmax related effects in CNS or cardiovascular system. In repeated dose toxicity studies in rats and dogs, flubendazole-induced changes were observed in haematological, lymphoid and gastrointestinal systems and in testes. In dogs, the liver was an additional target organ. Upon treatment cessation, at least partial recovery was observed for these changes in dogs. In rats, the No Observed Adverse Effect Level (NOAEL) was 5 mg (as base)/kg body weight/day (mg eq./kg/day) in males and 2.5 mg eq./kg/day in females. In dogs, the NOAEL was lower than 20 mg eq./kg/day. Regarding genotoxicity, flubendazole was negative in the Ames test, but positive in the in vivo micronucleus test.ConclusionsBased on these results, in combination with previously described genotoxicity and reproductive toxicity data and the outcome of the preclinical efficacy studies, it was concluded that no flubendazole treatment regimen can be selected that would provide efficacy in humans at safe exposure

Homeostasis, injury, and recovery dynamics at multiple scales in a self-organizing mouse intestinal crypt.

The maintenance of the functional integrity of the intestinal epithelium requires a tight coordination between cell production, migration, and shedding along the crypt-villus axis. Dysregulation of these processes may result in loss of the intestinal barrier and disease. With the aim of generating a more complete and integrated understanding of how the epithelium maintains homeostasis and recovers after injury, we have built a multi-scale agent-based model (ABM) of the mouse intestinal epithelium. We demonstrate that stable, self-organizing behaviour in the crypt emerges from the dynamic interaction of multiple signalling pathways, such as Wnt, Notch, BMP, ZNRF3/RNF43, and YAP-Hippo pathways, which regulate proliferation and differentiation, respond to environmental mechanical cues, form feedback mechanisms, and modulate the dynamics of the cell cycle protein network. The model recapitulates the crypt phenotype reported after persistent stem cell ablation and after the inhibition of the CDK1 cycle protein. Moreover, we simulated 5-fluorouracil (5-FU)-induced toxicity at multiple scales starting from DNA and RNA damage, which disrupts the cell cycle, cell signalling, proliferation, differentiation, and migration and leads to loss of barrier integrity. During recovery, our in silico crypt regenerates its structure in a self-organizing, dynamic fashion driven by dedifferentiation and enhanced by negative feedback loops. Thus, the model enables the simulation of xenobiotic-, in particular chemotherapy-, induced mechanisms of intestinal toxicity and epithelial recovery. Overall, we present a systems model able to simulate the disruption of molecular events and its impact across multiple levels of epithelial organization and demonstrate its application to epithelial research and drug development

Neurofibromatosis type 1-related pseudarthrosis: Beyond the pseudarthrosis site

Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder affecting approximately 1 in 2,000 newborns. Up to 5% of NF1 patients suffer from pseudarthrosis of a long bone (NF1-PA). Current treatments are often unsatisfactory, potentially leading to amputation. To gain more insight into the pathogenesis we cultured cells from PA tissue and normal-appearing periosteum of the affected bone for NF1 mutation analysis. PA cells were available from 13 individuals with NF1. Biallelic NF1 inactivation was identified in all investigated PA cells obtained during the first surgery. Three of five cases sampled during a later intervention showed biallelic NF1 inactivation. Also, in three individuals, we examined periosteum-derived cells from normal-appearing periosteum proximal and distal to the PA. We identified the same biallelic NF1 inactivation in the periosteal cells outside the PA region. These results indicate that NF1 inactivation is required but not sufficient for the development of NF1-PA. We observed that late-onset NF1-PA occurs and is not always preceded by congenital bowing. Furthermore, the failure to identify biallelic inactivation in two of five later interventions and one reintervention with a known somatic mutation indicates that NF1-PA can persist after the removal of most NF1 negative cells.status: publishe

A dynamic model of the intestinal epithelium integrates multiple sources of preclinical data and enables clinical translation of drug-induced toxicity.

We have built a quantitative systems toxicology modeling framework focused on the early prediction of oncotherapeutic-induced clinical intestinal adverse effects. The model describes stem and progenitor cell dynamics in the small intestinal epithelium and integrates heterogeneous epithelial-related processes, such as transcriptional profiles, citrulline kinetics, and probability of diarrhea. We fitted a mouse-specific version of the model to quantify doxorubicin and 5-fluorouracil (5-FU)-induced toxicity, which included pharmacokinetics and 5-FU metabolism and assumed that both drugs led to cell cycle arrest and apoptosis in stem cells and proliferative progenitors. The model successfully recapitulated observations in mice regarding dose-dependent disruption of proliferation which could lead to villus shortening, decrease of circulating citrulline, increased diarrhea risk, and transcriptional induction of the p53 pathway. Using a human-specific epithelial model, we translated the cytotoxic activity of doxorubicin and 5-FU quantified in mice into human intestinal injury and predicted with accuracy clinical diarrhea incidence. However, for gefitinib, a specific-molecularly targeted therapy, the mice failed to reproduce epithelial toxicity at exposures much higher than those associated with clinical diarrhea. This indicates that, regardless of the translational modeling approach, preclinical experimental settings have to be suitable to quantify drug-induced clinical toxicity with precision at the structural scale of the model. Our work demonstrates the usefulness of translational models at early stages of the drug development pipeline to predict clinical toxicity and highlights the importance of understanding cross-settings differences in toxicity when building these approaches

Neural network algorithm for detection of erosions and ankylosis on CT of the sacroiliac joints : multicentre development and validation of diagnostic accuracy

Objectives The aim was to evaluate the feasibility and diagnostic accuracy of deep learning for automated detection of structural lesions of sacroiliitis on multicentre pelvic CT scans. Methods A heterogeneous multi-scanner pelvic (DE)CT dataset of 145 patients (81 female, 121 Centre A/24 Centre B, 18-87 years old, mean 40±13 years, 2005-2021) with a clinical suspicion of sacroiliitis was retrospectively included. Ground truth pixelwise sacroiliac joint (SIJ) segmentation and structural lesion annotation was performed on axial CT-images by three independent radiologists separately, blinded for clinical information. Erosions were defined as cortical bone full thickness loss ≥1.0mm. Ankylosis was defined as SIJ bridging ≥2.0mm. The reference standard was reader-assessed presence of structural SIJ lesions. Preprocessing steps were performed to homogenize the heterogeneous original images from different scanners to conform to identical image quality to improve statistical outcome performance. A U-Net for SIJ segmentation and two separate convolutional neural networks (CNN) for erosion and ankylosis detection were trained. In-training validation and 10-fold validation testing (U-Net-n=10×58; CNN-n=10×29) on a separate test dataset were performed to assess performance on a slice-by-slice and patient level (dice coefficient/accuracy/sensitivity/specificity/positive and negative predictive value/ROC-AUC). Patient-level optimization was applied to increase the performance regarding predefined statistical metrics. Gradient-weighted class activation mapping (Grad-CAM++) heatmap explainability analysis highlighted image parts with statistically important regions for algorithmic decisions. Results In total, 84 patients had a diagnosis of spondyloarthritis, 15 had a mechanical low back and/or buttock pain origin and 46 had no clear diagnosis. Sixty-four patients had SIJ erosions, 28 had ankylosis, 14 had both and 67 had no structural lesions. Regarding SIJ segmentation, a training and test dice similarity coefficient of 0.89 and 0.75 were obtained. By segmenting the SIJs before the disease detection steps, the scans were reduced to one third of the total number of slices of the original CT scan. For slice-by-slice structural lesion detection, a sensitivity/specificity/ROC-AUC of 95%/89%/0.92 and 93%/91%/0.91 were obtained in the test dataset for erosion and ankylosis detection, respectively. For patient-level lesion detection after pipeline optimization for predefined statistical metrics, a sensitivity/specificity of 95%/85% and 82%/97% were obtained for erosion and ankylosis detection, respectively. Grad-CAM++ explainability analysis showed that the focus of the CNN to detect structural lesions is on the SIJ cortical edges, as intended. Conclusions An optimized deep learning pipeline, including an explainability analysis, detects structural lesions of sacroiliitis on pelvic CT scans with excellent statistical performance on a slice-by-slice and patient level

Legacy data sharing to improve drug safety assessment: The eTOX project

The sharing of legacy preclinical safety data among pharmaceutical companies and its integration with other information sources offers unprecedented opportunities to improve the early assessment of drug safety. Here, we discuss the experience of the eTOX project, which was established through the Innovative Medicines Initiative to explore this possibility