A single institution case series of ReCell® use in treating pediatric burns.

BACKGROUND: Thermal injury has a significant impact on disability and morbidity in pediatric patients. Challenges in caring for pediatric burn patients include limited donor sites for large total body surface area (TBSA) burn as well as optimization of wound management for long term growth and cosmesis. ReCell® technology produces autologous skin cell suspensions from minimal donor split-thickness skin samples, allowing for expanded coverage using minimal donor skin. Most literature on outcomes reports on adult patients. OBJECTIVE: We present the largest to-date retrospective review of ReCell® technology use in pediatric patients at a single pediatric burn center. METHOD: Patients were treated at a quaternary care, free-standing, American Burn Association verified Pediatric Burn Center. A retrospective chart review was performed from September 2019 to March 2022, during which time twenty-one pediatric burn patients had been treated with ReCell® technology. Patient information was collected, including demographics, hospital course, burn wound characteristics, number of ReCell® applications, adjunct procedures, complications, healing time, Vancouver scar scale measurements, and follow-up. A descriptive analysis was performed, and medians were reported. RESULTS: Median TBSA burn on initial presentation was 31% (ranging 4%-86%). The majority of patients (95.2%) had placement of a dermal substrate prior to ReCell® application. Four patients did not receive split thickness skin grafting with their ReCell® treatment. The median time between date of burn injury and first ReCell® application was 18 days (ranging 5-43 days). The number of ReCell® applications ranged from 1-4 per patient. Median time until wound was classified as healed was 81 days (ranging 39-573 days). The median maximum Vancouver scar scale measurement per patient at time healed was 8, ranging from 3-14. Five patients who received skin grafts had graft loss and three of these patients had graft loss from areas with ReCell®. CONCLUSION: ReCell® technology provides an additional method for wound coverage, either on its own or in conjunction with split thickness skin grafting, and is safe and effective in pediatric patients.

Length of Stay Per Total Body Surface Area Burn: A Validation Study Using the National Burn Registry.

A length of stay (LOS) of one day per percent total body surface area (TBSA) burn has been generally accepted but not validated in current pediatric burn studies. The primary objective of this study is to validate previous Pediatric Injury Quality Improvement Collaboration (PIQIC) findings by using a national burn registry to evaluate LOS per TBSA burn relative to burn mechanism, sociodemographic characteristics, and clinical factors which influence this ratio. We evaluated patients 0-18 years old who sustained a burn injury and whose demographics were submitted to the National Burn Registry (NBR) dataset from July 2008 through June 2018. Mixed effects generalized additive regression models were performed to identify characteristics associated with the LOS per TBSA burn ratio. Among 51,561 pediatric burn patients, 45% were Non-Hispanic White, 58% were male, and median age was 3.0 years old (IQR: 1.0, 9.0). The most common burn mechanism was scald (55.9%). The median LOS per TBSA burn ratio across all cases was 0.9 (IQR: 0.4, 1.75). In adjusted models, scald burns had a mean predicted LOS per TBSA burn value of 1.2 while chemical burns had the highest ratio (4.8). Non-Hispanic White patients had lower LOS per TBSA burn ratios than all other races and ethnicities (p < .05). These data substantiate evidence on variance in LOS per TBSA burn relative to burn mechanism and race/ethnicity. Knowing these variations can guide expectations in hospital LOS for patients and families and help burn centers benchmark their clinical performance.

Bioengineering of functional human induced pluripotent stem cell-derived intestinal grafts.

Patients with short bowel syndrome lack sufficient functional intestine to sustain themselves with enteral intake alone. Transplantable vascularized bioengineered intestine could restore nutrient absorption. Here we report the engineering of humanized intestinal grafts by repopulating decellularized rat intestinal matrix with human induced pluripotent stem cell-derived intestinal epithelium and human endothelium. After 28 days of in vitro culture, hiPSC-derived progenitor cells differentiate into a monolayer of polarized intestinal epithelium. Human endothelial cells seeded via native vasculature restore perfusability. Ex vivo isolated perfusion testing confirms transfer of glucose and medium-chain fatty acids from lumen to venous effluent. Four weeks after transplantation to RNU rats, grafts show survival and maturation of regenerated epithelium. Systemic venous sampling and positron emission tomography confirm uptake of glucose and fatty acids in vivo. Bioengineering intestine on vascularized native scaffolds could bridge the gap between cell/tissue-scale regeneration and whole organ-scale technology needed to treat intestinal failure patients.There is a need for humanised grafts to treat patients with intestinal failure. Here, the authors generate intestinal grafts by recellularizing native intestinal matrix with human induced pluripotent stem cell-derived epithelium and human endothelium, and show nutrient absorption after transplantation in rats.

Spray Delivery of Intestinal Organoids to Reconstitute Epithelium on Decellularized Native Extracellular Matrix.

The native extracellular matrix (ECM) serves as a unique platform for tissue engineering because it provides an organ-specific scaffold in terms of both matrix composition and tissue architecture. However, efficacious cell-seeding techniques for recellularizing the ECM constructs with appropriate cell types to restore biological function remain under development. In this study, the impact of spraying as a seeding technique for repopulation of decellularized small intestine was investigated. In a series of experiments, CaCo-2 cells were first used to investigate the effect of spray device type and pressure on cell viability and to optimize parameters for seeding intestinal epithelial cells. High cell viability and a homogeneous cell distribution were obtained when cell suspensions were sprayed through an airbrush at low pressure. Next, the effect of seeding method and spray pressure on the size and dispersal of intestinal organoids, a more complex and clinically relevant intestinal stem cell population, was evaluated. The feasibility of seeding intestinal epithelial cells onto decellularized scaffolds was next studied using sprayed CaCo-2 cells, which survived the spray-seeding process and formed a monolayer on the scaffold. Finally, airbrush seeding was used to spray intestinal organoids onto the scaffolds, with cell survival and tissue architecture evaluated after 1 week of culture. Organoids seeded through pipetting onto the decellularized scaffold survived, but demonstrated aggregation, with cells organized around multiple small lumens. In contrast, organoids airbrush spray seeded at 0.35 bar onto the decellularized scaffold not only engrafted but also demonstrated formation of an epithelial monolayer that resembled the absorptive surface found on intestinal villi. The results suggest that seeding cells through airbrush spraying holds great potential for use in tissue engineering, especially for large-scale tubular organ recellularization.

Bowel dysfunction following pullthrough surgery is associated with an overabundance of nitrergic neurons in Hirschsprung disease.

PURPOSE: Recent evidence suggests that patients with Hirschsprung disease (HD) have abnormal neurotransmitter expression in the ganglionated proximal colon. These alterations may cause persistent bowel dysfunction even after pullthrough surgery. We sought to quantify the proportion of nitrergic neurons in the ganglionic colon of HD patients and relate these findings to functional outcome. METHODS: The proximal resection margin from 17 patients with colonic HD who underwent a pullthrough procedure and colorectal tissue from 4 age-matched controls were immunohistochemically examined to quantify the proportion of nitrergic neurons. The incidence of constipation, incontinence, and enterocolitis in HD patients was assessed retrospectively and correlated with the proportion of nitric oxide synthase (NOS) expressing neurons. Neuronal subtypes in the ganglionic colon of the Edrnb-/- mouse model of HD were also studied. RESULTS: Mice with HD had a significantly higher proportion of NOS+ neurons in ganglionic colon than normal littermates (32.0±5.6% vs. 19.8±1.2%, p<0.01). Patients with HD also had significantly more NOS+ neurons than controls (18.4±4.6% vs. 13.1±1.9%, p<0.01). Patients who experienced constipation or enterocolitis postoperatively tended toward a higher proportion of NOS+ neurons (21.4±3.9% vs. 17.1±4.1%, p=0.06). Furthermore, patients with a proportion of NOS+ neurons above the median of all HD patients (18.3%) were significantly more likely to have constipation than those below the median (75% vs. 14%, p<0.05). CONCLUSION: An overabundance of nitrergic neurons in the proximal resection margin is associated with HD and may predict bowel dysfunction following pullthrough surgery.