Strategies for the Treatment of Infantile Soft Tissue Sarcomas With BCOR Alterations.

BCOR alterations are described in ultra-rare infantile soft tissue sarcomas including primitive myxoid mesenchymal tumor of infancy and undifferentiated round cell sarcoma (URCS). Previous reports often describe dismal outcomes. Thus, we undertook a retrospective, multi-institutional study of infants with BCOR -rearranged soft tissue sarcomas. Nine patients aged 6 weeks to 15 months were identified. One tumor carried a BCOR :: CCNB3 fusion, whereas 7 tumors harbored internal tandem duplication of BCOR , including 4 cases classified as primitive myxoid mesenchymal tumor of infancy, 1 case as URCS, and 2 cases characterized by a "hybrid morphology" in our evaluation. Four patients underwent upfront surgery with residual disease that progressed locally after a median of 2.5 months. Locoregional recurrences were observed in hybrid patients, and the URCS case recurred with brain metastases. Complete radiographic responses after chemotherapy were achieved in patients treated with vincristine/doxorubicin/cyclophosphamide alternating with ifosfamide/etoposide, vincristine/doxorubicin/cyclophosphamide alternating with cyclophosphamide/etoposide (regimen I), and ifosfamide/carboplatin/etoposide. Seven patients received radiotherapy. With a median of 23.5 months off therapy, 8 patients are with no evidence of disease. In our study, observation was inadequate for the management of untreated postsurgical residual disease. Tumors demonstrated chemosensitivity with anthracycline-based regimens and ifosfamide/carboplatin/etoposide. Radiotherapy was required to achieve durable response in most patients.

Successful Haploidentical Bone Marrow Transplantation of an Infant With a Novel Mutation in SAMD9L Gene (Ataxia-Pancytopenia Syndrome).

Data regarding the outcomes of hematopoietic stem cell transplant (HSCT) for the management of SAMD9L -associated ataxia-pancytopenia syndrome remains limited. We depict the case of a 2-month-old male with a novel mutation in the SAMD9L gene, presenting with respiratory failure, pancytopenia and severe developmental delay. He experienced graft failure 2 months after a 4/6 HLA-matched cord HSCT. At 9 months old, an unsuccessful unrelated donor search prompted a haploidentical HSCT with successful engraftment. He sustains excellent donor chimerism and has improved developmentally over 2 years posttransplant. This case demonstrates haploidentical HSCT as a viable option for patients with SAMD9L mutation and no acceptable unrelated donor.

Management of severe chronic pain with methadone in pediatric patients with sickle cell disease.

Vasocclusive pain crises are common among pediatric patients with sickle cell disease (SCD). Some patients with repeated pain crises develop chronic pain. We performed a retrospective cohort study of pediatric patients with SCD with chronic pain treated with methadone. We identified a significant reduction in pain hospitalizations following methadone treatment (0.35 ± 0.19 vs. 0.19 ± 0.17 hospitalizations/month, P = 0.016). In addition, we did not observe overt organ toxicity nor symptoms of opioid withdrawal during methadone wean. We suggest that methadone is safe and has some clinical benefit, which should be proven in prospective randomized trials for pediatric patients with SCD and chronic pain.

Cranial epidural hematomas: A case series and literature review of this rare complication associated with sickle cell disease.

BACKGROUND: Patients with sickle cell disease (SCD) may experience many complications of the central nervous system (CNS) including stroke, silent cerebral infarcts, and neuropsychological deficits. Cranial epidural hematoma is a rare but potentially serious complication. PROCEDURE: Case series of cranial epidural hematomas in children with SCD from three different institutions is considered, along with a literature review of cranial epidural hematomas in this population. RESULTS: Seven children with SCD with cranial epidural hematomas were identified from three different institutions. All patients were male and the age at presentation ranged from 10 to 18 years. Two patients presented with headache (28.6%), while the rest had no neurologic symptoms at presentation. Four patients required urgent neurosurgical intervention (57.1%) and one patient died (14.3%). A literature review identified 18 additional cases of cranial epidural hematomas in children with SCD. Of these, treatment ranged from supportive care to neurosurgical intervention. Twelve patients completely recovered (66.7%), one patient had long-term cognitive impairment (5.6%), and four patients died (22.2%). Combined with our data, cranial epidural hematomas have a mortality rate of 20.0%. CONCLUSIONS: Although rare, cranial epidural hematoma can be fatal and should be considered in patients with acute neurological symptoms.

Bnip3lb-driven mitophagy sustains expansion of the embryonic hematopoietic stem cell pool.

Embryonic hematopoietic stem and progenitor cells (HSPCs) have the unique ability to undergo rapid proliferation while maintaining multipotency, a clinically-valuable quality which currently cannot be replicated in vitro. Here, we show that embryonic HSPCs achieve this state by precise spatio-temporal regulation of reactive oxygen species (ROS) via Bnip3lb-associated developmentally-programmed mitophagy, a distinct autophagic regulatory mechanism from that of adult HSPCs. While ROS drives HSPC specification in the dorsal aorta, scRNAseq and live-imaging of Tg(ubi:mitoQC) zebrafish indicate that mitophagy initiates as HSPCs undergo endothelial-to-hematopoietic transition and colonize the caudal hematopoietic tissue (CHT). Knockdown of bnip3lb reduced mitophagy and HSPC numbers in the CHT by promoting myeloid-biased differentiation and apoptosis, which was rescued by anti-oxidant exposure. Conversely, induction of mitophagy enhanced both embryonic HSPC and lymphoid progenitor numbers. Significantly, mitophagy activation improved ex vivo functional capacity of hematopoietic progenitors derived from human-induced pluripotent stem cells (hiPSCs), enhancing serial-replating hematopoietic colony forming potential. HIGHLIGHTS: ROS promotes HSPC formation in the dorsal aorta but negatively affects maintenance thereafter.HSPCs colonizing secondary niches control ROS levels via Bnip3lb-directed mitophagy.Mitophagy protects nascent HSPCs from ROS-associated apoptosis and maintains multipotency.Induction of mitophagy enhances long-term hematopoietic potential of iPSC-derived HSPCs.

CellComm infers cellular crosstalk that drives haematopoietic stem and progenitor cell development.

Intercellular communication orchestrates a multitude of physiologic and pathologic conditions. Algorithms to infer cell-cell communication and predict downstream signalling and regulatory networks are needed to illuminate mechanisms of stem cell differentiation and tissue development. Here, to fill this gap, we developed and applied CellComm to investigate how the aorta-gonad-mesonephros microenvironment dictates haematopoietic stem and progenitor cell emergence. We identified key microenvironmental signals and transcriptional networks that regulate haematopoietic development, including Stat3, Nr0b2, Ybx1 and App, and confirmed their roles using zebrafish, mouse and human models. Notably, CellComm revealed extensive crosstalk among signalling pathways and convergence on common transcriptional regulators, indicating a resilient developmental programme that ensures dynamic adaptation to changes in the embryonic environment. Our work provides an algorithm and data resource for the scientific community.