Clinical Utility of Laser Speckle Contrast Imaging and Real-Time Quantification of Bowel Perfusion in Minimally Invasive Left-Sided Colorectal Resections.

BACKGROUND: Left-sided colorectal surgery demonstrates high anastomotic leak rates, with tissue ischemia thought to influence outcomes. Indocyanine green is commonly used for perfusion assessment, but evidence remains mixed for whether it reduces colorectal anastomotic leaks. Laser speckle contrast imaging provides dye-free perfusion assessment in real-time through perfusion heat maps and quantification. OBJECTIVE: This study investigates the efficacy of advanced visualization (indocyanine green versus laser speckle contrast imaging), perfusion assessment, and utility of laser speckle perfusion quantification in determining ischemic margins. DESIGN: Prospective intervention group using advanced visualization with case-matched, retrospective control group. SETTINGS: Single academic medical center. PATIENTS: Forty adult patients undergoing elective, minimally invasive, left-sided colorectal surgery. INTERVENTIONS: Intraoperative perfusion assessment using white light imaging and advanced visualization at 3 time points: T1-proximal colon after devascularization, before transection, T2-proximal/distal colon before anastomosis, and T3-completed anastomosis. MAIN OUTCOME MEASURES: Intraoperative indication of ischemic line of demarcation before resection under each visualization method, surgical decision change using advanced visualization, post hoc laser speckle perfusion quantification of colorectal tissue, and 30-day postoperative outcomes. RESULTS: Advanced visualization changed surgical decision-making in 17.5% of cases. For cases in which surgeons changed a decision, the average discordance between the line of demarcation in white light imaging and advanced visualization was 3.7 cm, compared to 0.41 cm ( p = 0.01) for cases without decision changes. There was no statistical difference between the line of ischemic demarcation using laser speckle versus indocyanine green ( p = 0.16). Laser speckle quantified lower perfusion values for tissues beyond the line of ischemic demarcation while suggesting an additional 1 cm of perfused tissue beyond this line. One (2.5%) anastomotic leak occurred in the intervention group. LIMITATIONS: This study was not powered to detect differences in anastomotic leak rates. CONCLUSIONS: Advanced visualization using laser speckle and indocyanine green provides valuable perfusion information that impacts surgical decision-making in minimally invasive left-sided colorectal surgeries. See Video Abstract . UTILIDAD CLNICA DE LAS IMGENES DE CONTRASTE MOTEADO CON LSER Y LA CUANTIFICACIN EN TIEMPO REAL DE LA PERFUSIN INTESTINAL EN RESECCIONES COLORRECTALES DEL LADO IZQUIERDO MNIMAMENTE INVASIVAS: ANTECEDENTES:La cirugía colorrectal del lado izquierdo demuestra altas tasas de fuga anastomótica, y se cree que la isquemia tisular influye en los resultados. El verde de indocianina se utiliza habitualmente para evaluar la perfusión, pero la evidencia sobre si reduce las fugas anastomóticas colorrectales sigue siendo contradictoria. Las imágenes de contraste moteado con láser proporcionan una evaluación de la perfusión sin colorantes en tiempo real a través de mapas de calor de perfusión y cuantificación.OBJETIVO:Este estudio investiga la eficacia de la evaluación de la perfusión mediante visualización avanzada (verde de indocianina versus imágenes de contraste moteado con láser) y la utilidad de la cuantificación de la perfusión con moteado láser para determinar los márgenes isquémicos.DISEÑO:Grupo de intervención prospectivo que utiliza visualización avanzada con un grupo de control retrospectivo de casos emparejados.LUGARES:Centro médico académico único.PACIENTES:Cuarenta pacientes adultos sometidos a cirugía colorrectal electiva, mínimamente invasiva, del lado izquierdo.INTERVENCIONES:Evaluación de la perfusión intraoperatoria mediante imágenes con luz blanca y visualización avanzada en tres puntos temporales: T1-colon proximal después de la devascularización, antes de la transección; T2-colon proximal/distal antes de la anastomosis; y T3-anastomosis completa.PRINCIPALES MEDIDAS DE VALORACIÓN:Indicación intraoperatoria de la línea de demarcación isquémica antes de la resección bajo cada método de visualización, cambio de decisión quirúrgica mediante visualización avanzada, cuantificación post-hoc de la perfusión con láser moteado del tejido colorrectal y resultados posoperatorios a los 30 días.RESULTADOS:La visualización avanzada cambió la toma de decisiones quirúrgicas en el 17,5% de los casos. Para los casos en los que los cirujanos cambiaron una decisión, la discordancia promedio entre la línea de demarcación en las imágenes con luz blanca y la visualización avanzada fue de 3,7 cm, en comparación con 0,41 cm (p = 0,01) para los casos sin cambios de decisión. No hubo diferencias estadísticas entre la línea de demarcación isquémica utilizando láser moteado versus verde de indocianina (p = 0,16). El moteado con láser cuantificó valores de perfusión más bajos para los tejidos más allá de la línea de demarcación isquémica y al mismo tiempo sugirió 1 cm adicional de tejido perfundido más allá de esta línea. Se produjo una fuga anastomótica (2,5%) en el grupo de intervención.LIMITACIONES:Este estudio no tuvo el poder estadístico suficiente para detectar diferencias en las tasas de fuga anastomótica.CONCLUSIONES:La visualización avanzada utilizando moteado láser y verde de indocianina proporciona información valiosa sobre la perfusión que impacta la toma de decisiones quirúrgicas en cirugías colorrectales mínimamente invasivas del lado izquierdo. (Traducción-Dr. Ingrid Melo).

An enhanced Lactobacillus reuteri biofilm formulation that increases protection against experimental necrotizing enterocolitis.

One significant drawback of current probiotic therapy for the prevention of necrotizing enterocolitis (NEC) is the need for at least daily administration because of poor probiotic persistence after enteral administration, increasing the risk of the probiotic bacteria causing bacteremia or sepsis if the intestines are already compromised. We previously showed that the effectiveness of Lactobacillus reuteri ( Lr) in preventing NEC is enhanced when Lr is grown as a biofilm on the surface of dextranomer microspheres (DM). Here we sought to test the efficacy of Lr administration by manipulating the Lr biofilm state with the addition of biofilm-promoting substances (sucrose and maltose) to DM or by mutating the Lr gtfW gene (encoding an enzyme central to biofilm production). Using an animal model of NEC, we determined that Lr adhered to sucrose- or maltose-loaded DM significantly reduced histologic injury, improved host survival, decreased intestinal permeability, reduced intestinal inflammation, and altered the gut microbiome compared with Lr adhered to unloaded DM. These effects were abolished when DM or GtfW were absent from the Lr inoculum. This demonstrates that a single dose of Lr in its biofilm state decreases NEC incidence. Importantly, preloading DM with sucrose or maltose further enhances Lr protection against NEC in a GtfW-dependent fashion, demonstrating the tunability of the approach and the potential to use other cargos to enhance future probiotic formulations. NEW & NOTEWORTHY Previous clinical trials of probiotics to prevent necrotizing enterocolitis have had variable results. In these studies, probiotics were delivered in their planktonic, free-living form. We have developed a novel probiotic delivery system in which Lactobacillus reuteri (Lr) is delivered in its biofilm state. In a model of experimental necrotizing enterocolitis, this formulation significantly reduces intestinal inflammation and permeability, improves survival, and preserves the natural gut microflora compared with the administration of Lr in its free-living form.

Treatment of experimental necrotizing enterocolitis with stem cell-derived exosomes.

PURPOSE: Necrotizing enterocolitis (NEC) remains a devastating disease in premature infants. We previously showed that four stem cell (SC) types equivalently improve experimental NEC. Exosomes are intercellular nanovesicles containing RNA, miRNA, DNA, and protein. Because SC therapy faces challenges, our aim was to determine if the beneficial effects of SC are achievable with cell-free exosomes. METHODS: Exosomes from four SC types were compared: (1) amniotic fluid-derived mesenchymal SC (AF-MSC); (2) bone marrow-derived MSC (BM-MSC); (3) amniotic fluid-derived neural SC (AF-NSC); and (4) neonatal enteric NSC (E-NSC). Rat pups exposed to NEC received a varying concentration of a single type of exosome with control pups receiving PBS only. Intestinal damage was graded histologically. RESULTS: The incidence of NEC was 0% in unstressed pups and 60.7% in control pups subjected to NEC. Exosomes (4.0×108) reduced NEC incidence to: AF-MSC 25.0%; BM-MSC 23.1%; AF-NSC 11.1%; E-NSC 27.3%. When administered at a concentration of at least 4.0×108, all groups demonstrated a significant reduction in NEC compared to untreated pups. At this minimum concentration, there was no difference in treatment efficacy between exosomes and the SC from which they were derived. CONCLUSION: Stem cell-derived exosomes reduce the incidence and severity of experimental NEC as effectively as the stem cells from which they are derived, supporting the potential for novel cell-free exosome therapy for NEC. TYPE OF STUDY: Basic science.

Stem cell therapy in necrotizing enterocolitis: Current state and future directions.

Stem cell therapy is a promising treatment modality for necrotizing enterocolitis. Among the many promising stem cells identified to date, it is likely that mesenchymal stem cells will be the most useful and practical cell-based therapies for this condition. Using acellular components such as exosomes or other paracrine mediators are promising as well. Multiple mechanisms are likely at play in the positive effects provided by these cells, and further research is underway to further elucidate these effects.

Evaluating the efficacy of different types of stem cells in preserving gut barrier function in necrotizing enterocolitis.

BACKGROUND: Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in premature infants. Increased intestinal permeability is central to NEC development. We have shown that stem cells (SCs) can reduce the incidence and severity of NEC. Our current goal was to investigate the efficacy of four different types of SC in preservation of gut barrier function during NEC. MATERIALS AND METHODS: We compared (1) amniotic fluid-derived mesenchymal SC, (2) bone marrow-derived mesenchymal SC, (3) amniotic fluid-derived neural SC, and (4) enteric neural SC. Premature rat pups received an intraperitoneal injection of 2 × 106 SC or phosphate-buffered saline only and were then subjected to experimental NEC. Control pups were breastfed and not subjected to NEC. After 48 h, animals received a single enteral dose of fluorescein isothiocyanate -labeled dextran (FD70), were sacrificed 4 h later, and serum FD70 concentrations determined. RESULTS: Compared to breastfed, unstressed pups with intact gut barrier function and normal intestinal permeability (serum FD70 concentration 2.22 ± 0.271 µg/mL), untreated pups exposed to NEC had impaired barrier function with significantly increased permeability (18.6 ± 4.25 µg/mL, P = 0.047). Pups exposed to NEC but treated with SC had significantly reduced intestinal permeability: Amniotic fluid-derived mesenchymal SC (9.45 ± 1.36 µg/mL, P = 0.017), bone marrow-derived mesenchymal SC (6.73 ± 2.74 µg/mL, P = 0.049), amniotic fluid-derived neural SC (8.052 ± 1.31 µg/mL, P = 0.0496), and enteric neural SC (6.60 ± 1.46 µg/mL, P = 0.033). CONCLUSIONS: SCs improve gut barrier function in experimental NEC. Although all four types of SC reduce permeability equivalently, SC derived from amniotic fluid may be preferable due to availability at delivery and ease of culture, potentially enhancing clinical translation.

Stem cells and necrotizing enterocolitis: A direct comparison of the efficacy of multiple types of stem cells.

PURPOSE: Necrotizing enterocolitis (NEC) is a leading cause of gastrointestinal morbidity and mortality in premature infants. While studies have shown potential for stem cell (SC) therapy in experimental NEC, no study has compared different SC side-by-side. Our purpose was to determine whether one type of SC may more effectively treat NEC than others. METHODS: Four SC were compared: (1) amniotic fluid-derived mesenchymal SC (AF-MSC); (2) amniotic fluid-derived neural SC (AF-NSC); (3) bone marrow-derived mesenchymal SC (BM-MSC); and (4) neonatal enteric neural SC (E-NSC). Using an established rat model of NEC, pups delivered prematurely received an intraperitoneal injection of SC. Control pups were injected with PBS. Additional controls were breast-fed by surrogates and not subjected to experimental NEC. Intestinal tissue was graded histologically. RESULTS: NEC incidence was: PBS, 61.3%; breast-fed unstressed, 0%; AF-MSC, 19.1%; BM-MSC, 22.9%; AF-NSC, 18.9%; E-NSC 22.2%. All groups demonstrated statistical significance (p<0.05) compared to controls, and there was no difference between SC groups. CONCLUSION: All four SC groups reduced the incidence and severity of experimental NEC equivalently. AF-MSC may be preferable because of availability of AF at delivery and ease of expansion, increasing potential for clinical translation. LEVEL OF EVIDENCE: V (Animal study).