Evaluation of the optical and biomechanical properties of bioengineered human skin generated with fibrin-agarose biomaterials

Significance: Recent generation of bioengineered human skin allowed the efficient treatment of patients with severe skin defects. However, the optical and biomechanical properties of these models are not known. Aim: Three models of bioengineered human skin based on fibrin-agarose biomaterials (acellular, dermal skin substitutes, and complete dermoepidermal skin substitutes) were generated and analyzed. Approach: Optical and biomechanical properties of these artificial human skin substitutes were investigated using the inverse adding-doubling method and tensile tests, respectively. Results: The analysis of the optical properties revealed that the model that most resembled the optical behavior of the native human skin in terms of absorption and scattering properties was the dermoepidermal human skin substitutes after 7 to 14 days in culture. The time-course evaluation of the biomechanical parameters showed that the dermoepidermal substitutes displayed significant higher values than acellular and dermal skin substitutes for all parameters analyzed and did not differ from the control skin for traction deformation, stress, and strain at fracture break. Conclusions: We demonstrate the crucial role of the cells from a physical point of view, confirming that a bioengineered dermoepidermal human skin substitute based on fibrin-agarose biomaterials is able to fulfill the minimal requirements for skin transplants for future clinical use at early stages of in vitro development.Ministry of Science, Innovation and Universities of Spain PGC2018-101904-A-I0Instituto de Salud Carlos III (ISCIII), Ministry of Science, Innovation and Universities, through AES 2017 AC17/00013Instituto de Salud Carlos III (ISCIII), Ministry of Science, Innovation and Universities within EuroNanoMed framework, EU AC17/00013University of Granada A.TEP.280.UGR18Junta de Andalucía PE-0395-2019Fundación Benéfica Anticancer San Francisco Javier y Santa Cándida, Granada, SpainOTRI.35A-0

Optical Behavior of Human Skin Substitutes: Absorbance in the 200–400 nm UV Range

The most recent generation of bioengineered human skin allows for the efficient treatment of patients with severe skin defects. Despite UV sunlight can seriously affect human skin, the optical behavior in the UV range of skin models is still unexplored. In the present study, absorbance and transmittance of the UGRSKIN bioartificial skin substitute generated with human skin cells combined with fibrin-agarose biomaterials were evaluated for: UV-C (200–280 nm), -B (280–315 nm), and -A (315–400 nm) spectral range after 7, 14, 21 and 28 days of ex vivo development. The epidermis of the bioartificial skin substitute was able to mature and differentiate in a time-dependent manner, expressing relevant molecules able to absorb most of the incoming UV radiation. Absorbance spectral behavior of the skin substitutes showed similar patterns to control native skin (VAF > 99.4%), with values 0.85–0.90 times lower than control values at 7 and 14- days and 1.05–1.10 times the control values at 21- and 28-days. UV absorbance increased, and UV transmission decreased with culture time, and comparable results to the control were found at 21 and 28 days. These findings support the use of samples corresponding to 21 or 28 days of development for clinical purposes due to their higher histological similarities with native skin, but also because of their absorbance of UV radiation.Junta de Andalucia PE-0395-2019University of Granada B-CTS-450-UGR20 A.TEP.280.UGR18Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades B-CTS-450-UGR20European Regional Development Fund (ERDF) through the "Una manera de hacer Europa" program Junta de Andalucia P20-00200Spanish Government PGC2018-101904-A-10

Long-Term in vivo Evaluation of Orthotypical and Heterotypical Bioengineered Human Corneas

Purpose: Human cornea substitutes generated by tissue engineering currently require limbal stem cells for the generation of orthotypical epithelial cell cultures. We recently reported that bioengineered corneas can be fabricated in vitro from a heterotypical source obtained from Wharton’s jelly in the human umbilical cord (HWJSC). Methods: Here, we generated a partial thickness cornea model based on plastic compression nanostructured fibrin-agarose biomaterials with cornea epithelial cells on top, as an orthotypical model (HOC), or with HWJSC, as a heterotypical model (HHC), and determined their potential in vivo usefulness by implantation in an animal model. Results: No major side effects were seen 3 and 12 months after implantation of either bioengineered partial cornea model in rabbit corneas. Clinical results determined by slit lamp and optical coherence tomography were positive after 12 months. Histological and immunohistochemical findings demonstrated that in vitro HOC and HHC had moderate levels of stromal and epithelial cell marker expression, whereas in vivo grafted corneas were more similar to control corneas. Conclusion: These results suggest that both models are potentially useful to treat diseases requiring anterior cornea replacement, and that HHC may be an efficient alternative to the use of HOC which circumvents the need to generate cornea epithelial cell cultures.Spanish Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica (I CD Ci) from the Spanish Ministry of Science and Innovation: Instituto de Salud Carlos III FIS PI17/0391 FIS PI14/0955European Union (EU)Spanish Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica (I CD Ci) from the Spanish Ministry of Science and Innovation: Ministry of Science, Innovation and Universities of Spain PGC2018-101904-A-I00 RTC-2017-6696-

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Application of optical methods for the evaluation of human tissues generated by tissue engineering

Tesis Univ. Granada. Departamento de Óptic

Generation and characterization of an in vivo model of corneal lesion for use in tissue engineering

Objetivos: En el presente estudio se pretende generar y caracterizar un modelo lesional corneal ex vivo, con el fin de poder evaluar la viabilidad de los tejidos artificiales creados mediante Ingeniería Tisular a través de la aplicación de una causticación controlada con NaOH sobre córneas de cerdo. Métodos: Se llevó a cabo un estudio descriptivo tomando 18 ojos de cerdos adultos, inmediatamente después de morir. Los globos oculares se introdujeron en NaOH 1,5 M durante 1, 2, 3 y 5 minutos. Tras lo cual se lavaron con agua corriente (5 minutos) y se realizó un lavado rápido con PBS, seguido de un lavado de 2 minutos en PBS. Se incluyeron dos grupos control: uno de córneas no tratadas, y otro de córneas a las que se les realizó lavados de agua corriente y PBS. Las muestras fueron procesadas para el análisis histológico mediante microscopía óptica con las tinciones de hematoxilina eosina, picrosirius y azul alcian. Se determinó la significación de los resultados obtenidos mediante el análisis estadístico ANOVA. Resultados: Se observó una pérdida del endotelio y del epitelio corneal en todos los grupos tratados con NaOH. Asimismo se objetivó una tendencia a la compactación de las fibras colágenas tras el tratamiento con NaOH en la tinción de picrosirius y la pérdida de fibras de coloración verde en las muestras tratadas con NaOH con respecto a los controles. Pese a observarse una menor intensidad en la tinción de azul alcian en la región posterior con respecto a las otras dos y entre las distintas muestras tratadas con NaOH, no se encontraron diferencias significativas en este aspecto. Conclusiones: se ha logrado crear un modelo lesional sencillo, de bajo coste y que no implica problemas éticos, que permitiría evaluar los tejidos artificiales creados mediante Ingeniería Tisular.Purpose: This study aims to generate and characterize an ex vivo corneal injury model, in order to assess the feasibility of artificial tissues created by using tissue engineering through the application of a corneal alkali burn with NaOH on porcine corneas. Methods: We conducted a descriptive study taking 18 eyes of adult pigs immediately after their death. Eyes were introduced on 1.5M NaOH for 1, 2, 3 and 5 minutes. After, they were washed with running water (5 min) and rapid washing with PBS, followed by a 2 minute wash in PBS was performed. Two control groups were included: untreated corneas and another corneas were performed running water washes and PBS whashes. Samples were processed for histological analysis by light microscopy with hematoxylin and eosin, alcian blue and picrosirius staining. The significance of the results was determined by ANOVA statistical analysis. Results: We observed a loss of endothelium and the corneal epithelium in all groups treated with NaOH. A tendency to compaction of collagen fibers after treatment with NaOH and picrosirius stain loss of green coloration fibers in samples treated with NaOH with respect to controls was also observed. Despite lower intensity observed in alcian blue staining in the posterior region compared to the other two and between samples treated with NaOH, no significant differences were found in this area. Conclusions: it has created a single lesion model, low cost and does not involve ethical issues, to assess the tissue created by Tissue Engineering.Beca de Iniciación a la Investigación de la Universidad de Granad

The surgical safety checklist and patient outcomes after surgery: a prospective observational cohort study, systematic review and meta-analysis

© 2017 British Journal of Anaesthesia Background: The surgical safety checklist is widely used to improve the quality of perioperative care. However, clinicians continue to debate the clinical effectiveness of this tool. Methods: Prospective analysis of data from the International Surgical Outcomes Study (ISOS), an international observational study of elective in-patient surgery, accompanied by a systematic review and meta-analysis of published literature. The exposure was surgical safety checklist use. The primary outcome was in-hospital mortality and the secondary outcome was postoperative complications. In the ISOS cohort, a multivariable multi-level generalized linear model was used to test associations. To further contextualise these findings, we included the results from the ISOS cohort in a meta-analysis. Results are reported as odds ratios (OR) with 95% confidence intervals. Results: We included 44 814 patients from 497 hospitals in 27 countries in the ISOS analysis. There were 40 245 (89.8%) patients exposed to the checklist, whilst 7508 (16.8%) sustained ≥1 postoperative complications and 207 (0.5%) died before hospital discharge. Checklist exposure was associated with reduced mortality [odds ratio (OR) 0.49 (0.32–0.77); P\u3c0.01], but no difference in complication rates [OR 1.02 (0.88–1.19); P=0.75]. In a systematic review, we screened 3732 records and identified 11 eligible studies of 453 292 patients including the ISOS cohort. Checklist exposure was associated with both reduced postoperative mortality [OR 0.75 (0.62–0.92); P\u3c0.01; I2=87%] and reduced complication rates [OR 0.73 (0.61–0.88); P\u3c0.01; I2=89%). Conclusions: Patients exposed to a surgical safety checklist experience better postoperative outcomes, but this could simply reflect wider quality of care in hospitals where checklist use is routine

Prospective observational cohort study on grading the severity of postoperative complications in global surgery research

Background The Clavien–Dindo classification is perhaps the most widely used approach for reporting postoperative complications in clinical trials. This system classifies complication severity by the treatment provided. However, it is unclear whether the Clavien–Dindo system can be used internationally in studies across differing healthcare systems in high- (HICs) and low- and middle-income countries (LMICs). Methods This was a secondary analysis of the International Surgical Outcomes Study (ISOS), a prospective observational cohort study of elective surgery in adults. Data collection occurred over a 7-day period. Severity of complications was graded using Clavien–Dindo and the simpler ISOS grading (mild, moderate or severe, based on guided investigator judgement). Severity grading was compared using the intraclass correlation coefficient (ICC). Data are presented as frequencies and ICC values (with 95 per cent c.i.). The analysis was stratified by income status of the country, comparing HICs with LMICs. Results A total of 44 814 patients were recruited from 474 hospitals in 27 countries (19 HICs and 8 LMICs). Some 7508 patients (16·8 per cent) experienced at least one postoperative complication, equivalent to 11 664 complications in total. Using the ISOS classification, 5504 of 11 664 complications (47·2 per cent) were graded as mild, 4244 (36·4 per cent) as moderate and 1916 (16·4 per cent) as severe. Using Clavien–Dindo, 6781 of 11 664 complications (58·1 per cent) were graded as I or II, 1740 (14·9 per cent) as III, 2408 (20·6 per cent) as IV and 735 (6·3 per cent) as V. Agreement between classification systems was poor overall (ICC 0·41, 95 per cent c.i. 0·20 to 0·55), and in LMICs (ICC 0·23, 0·05 to 0·38) and HICs (ICC 0·46, 0·25 to 0·59). Conclusion Caution is recommended when using a treatment approach to grade complications in global surgery studies, as this may introduce bias unintentionally

Critical care admission following elective surgery was not associated with survival benefit: prospective analysis of data from 27 countries

This was an investigator initiated study funded by Nestle Health Sciences through an unrestricted research grant, and by a National Institute for Health Research (UK) Professorship held by RP. The study was sponsored by Queen Mary University of London