Management of pediatric renal trauma: Results from the American Association for Surgery and Trauma Multi-Institutional Pediatric Acute Renal Trauma Study

BACKGROUND

Pediatric renal trauma is rare and lacks sufficient population-specific data to generate evidence-based management guidelines. A nonoperative approach is preferred and has been shown to be safe. However, bleeding risk assessment and management of collecting system injury are not well understood. We introduce the Multi-institutional Pediatric Acute Renal Trauma Study (Mi-PARTS), a retrospective cohort study designed to address these questions. This article describes the demographics and contemporary management of pediatric renal trauma at Level I trauma centers in the United States.

METHODS

Retrospective data were collected at 13 participating Level I trauma centers on pediatric patients presenting with renal trauma between 2010 and 2019. Data were gathered on demographics, injury characteristics, management, and short-term outcomes. Descriptive statistics were used to report on demographics, acute management, and outcomes.

RESULTS

In total, 1,216 cases were included in this study. Of all patients, 67.2% were male, and 93.8% had a blunt injury mechanism. In addition, 29.3% had isolated renal injuries, and 65.6% were high-grade (American Association for the Surgery of Trauma Grades III-V) injuries. The mean Injury Severity Score was 20.5. Most patients were managed nonoperatively (86.4%), and 3.9% had an open surgical intervention, including 2.7% having nephrectomy. Angioembolization was performed in 0.9%. Collecting system intervention was performed in 7.9%. Overall mortality was 3.3% and was only observed in patients with multiple injuries. The rate of avoidable transfer was 28.2%.

CONCLUSION

The management and outcomes of pediatric renal trauma lack data to inform evidence-based guidelines. Nonoperative management of bleeding following renal injury is a well-established practice. Intervention for renal trauma is rare. Our findings reinforce differences from the adult population and highlights opportunities for further investigation. With data made available through Mi-PARTS, we aimed to answer pediatric specific questions, including a pediatric-specific bleeding risk nomogram, and better understanding indications for interventions for collecting system injuries.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Genetically corrected RAG2-SCID human hematopoietic stem cells restore V(D)J-recombinase and rescue lymphoid deficiency

ABSTRACT

Recombination-activating genes (RAG1 and RAG2) are critical for lymphoid cell development and function by initiating the variable (V), diversity (D), and joining (J) (V(D)J)-recombination process to generate polyclonal lymphocytes with broad antigen specificity. The clinical manifestations of defective RAG1/2 genes range from immune dysregulation to severe combined immunodeficiencies (SCIDs), causing life-threatening infections and death early in life without hematopoietic cell transplantation (HCT). Despite improvements, haploidentical HCT without myeloablative conditioning carries a high risk of graft failure and incomplete immune reconstitution. The RAG complex is only expressed during the G0-G1 phase of the cell cycle in the early stages of T- and B-cell development, underscoring that a direct gene correction might capture the precise temporal expression of the endogenous gene. Here, we report a feasibility study using the CRISPR/Cas9-based "universal gene-correction" approach for the RAG2 locus in human hematopoietic stem/progenitor cells (HSPCs) from healthy donors and RAG2-SCID patient. V(D)J-recombinase activity was restored after gene correction of RAG2-SCID-derived HSPCs, resulting in the development of T-cell receptor (TCR) αβ and γδ CD3+ cells and single-positive CD4+ and CD8+ lymphocytes. TCR repertoire analysis indicated a normal distribution of CDR3 length and preserved usage of the distal TRAV genes. We confirmed the in vivo rescue of B-cell development with normal immunoglobulin M surface expression and a significant decrease in CD56bright natural killer cells. Together, we provide specificity, toxicity, and efficacy data supporting the development of a gene-correction therapy to benefit RAG2-deficient patients.

Improved Genome Editing through Inhibition of FANCM and Members of the BTR Dissolvase Complex

Recombinant adeno-associated virus (rAAV) vectors have the unique property of being able to perform genomic targeted integration (TI) without inducing a double-strand break (DSB). In order to improve our understanding of the mechanism behind TI mediated by AAV and improve its efficiency, we performed an unbiased genetic screen in human cells using a promoterless AAV-homologous recombination (AAV-HR) vector system. We identified that the inhibition of the Fanconi anemia complementation group M (FANCM) protein enhanced AAV-HR-mediated TI efficiencies in different cultured human cells by ∼6- to 9-fold. The combined knockdown of the FANCM and two proteins also associated with the FANCM complex, RecQ-mediated genome instability 1 (RMI1) and Bloom DNA helicase (BLM) from the BLM-topoisomerase IIIα (TOP3A)-RMI (BTR) dissolvase complex (RMI1, having also been identified in our screen), led to the enhancement of AAV-HR-mediated TI up to ∼17 times. AAV-HR-mediated TI in the presence of a nuclease (CRISPR-Cas9) was also increased by ∼1.5- to 2-fold in FANCM and RMI1 knockout cells, respectively. Furthermore, knockdown of FANCM in human CD34⁺ hematopoietic stem and progenitor cells (HSPCs) increased AAV-HR-mediated TI by ∼3.5-fold. This study expands our knowledge on the mechanisms related to AAV-mediated TI, and it highlights new pathways that might be manipulated for future improvements in AAV-HR-mediated TI.

The Binns Program for Cord Blood Research: A novel model of cord blood banking for academic biomedical research

Umbilical cord blood is an important graft source in the treatment of many genetic, hematologic, and immunologic disorders by hematopoietic stem cell transplantation. Millions of cord blood units have been collected and stored for clinical use since the inception of cord blood banking in 1989. However, the use of cord blood in biomedical research has been limited by access to viable samples. Here, we present a cost-effective, self-sustaining model for the procurement of fresh umbilical cord blood components for research purposes within hospital-affiliated academic institutions.

CRISPR-based gene editing enables FOXP3 gene repair in IPEX patient cells

The prototypical genetic autoimmune disease is immune dysregulation polyendocrinopathy enteropathy X-linked (IPEX) syndrome, a severe pediatric disease with limited treatment options. IPEX syndrome is caused by mutations in the forkhead box protein 3 (FOXP3) gene, which plays a critical role in immune regulation. As a monogenic disease, IPEX is an ideal candidate for a therapeutic approach in which autologous hematopoietic stem and progenitor (HSPC) cells or T cells are gene edited ex vivo and reinfused. Here, we describe a CRISPR-based gene correction permitting regulated expression of FOXP3 protein. We demonstrate that gene editing preserves HSPC differentiation potential, and that edited regulatory and effector T cells maintain their in vitro phenotype and function. Additionally, we show that this strategy is suitable for IPEX patient cells with diverse mutations. These results demonstrate the feasibility of gene correction, which will be instrumental for the development of therapeutic approaches for other genetic autoimmune diseases.