Continence management in children with severe caudal regression syndrome: role of multidisciplinary team and long-term follow-up.

PURPOSE: Caudal regression syndrome (CRS) is a rare congenital abnormality including orthopedic deformities, urological, anorectal, and cardiac malformations. The clinical spectrum of CRS varies in severity, therefore multiple surgeries and complex medical care may be required with the efforts and support of a multidisciplinary team to ensure the most accurate treatment and the best outcome. The aim of our retrospective study was to evaluate the role of a multidisciplinary treatment and the long-term outcome in patients with severe CRS. METHODS: Clinical, surgical and psychological data were collected for all patients with diagnosis of CRS, treated at our Pediatric Hospital from January 1995 to December 2020. Patients with a severe form of CRS according to Pang's classification were included in the study. All patients have been followed by a multidisciplinary team composed by urologists, neurosurgeons, neonatal and digestive surgeons, orthopedic surgeon, physiatrists and psychologists. On admission, patients were screened for CRS with sacrum, spine and legs X-ray, spine MRI, renal ultrasound, voiding cystography and urodynamic, and renography. Clinical data about bowel function were evaluated. RESULTS: During the study period, 55 patients with CRS were treated at our Institution. Six out of 55 (10.9%), presented with severe form of CRS (5 pts with type 1; 1 pt, with type 2) and represent our study group. Diagnosis of severe CRS was made at birth because of the typical deformities of the pelvis (fusion of the iliac wings), and of the lower extremities (undeveloped legs with flexion of the knees, clubfoot). All patients presented with neurogenic bladder, 4/6 (66.6%) with vesicoureteral reflux (VUR) and 2/6 (33.3%) with renal agenesia and contralateral ectopic hypoplastic kidney. Bowel symptoms occurred in 5/6 pts (83.3%). All patients were started with an earlier clean intermittent catheterization (CIC) regimen. In 3 patients oxybutynin has been effective or well tolerated, while in other 3 onabotulinumtoxin A has been used. Vesicoureteral reimplantation has been performed in 1 patient, 2 required endoscopic treatment of VUR. On long-term, 2 patients required bladder augmentation with ileum and appendicostomy (Mitrofanoff). Low adherences in CIC have been observed in three patients, mainly at puberty. Two patients presented with chronic renal failure. One patient reported suicide proposal. Regarding social life, only one is regularly performing sport activity. CONCLUSION: CRS is characterized by maldevelopment of the caudal half of the body with variable involvement of the gastrointestinal, genitourinary, skeletal, and nervous systems. Management of CRS includes a wide variety of interventions to address the full spectrum of possible anatomical abnormalities. Hence, a multidisciplinary team is also mandatory for a correct bladder and bowel management, in order to maintain continence and preserve renal function, improve quality of life and increase self-esteem.

Development of a porcine acellular bladder matrix for tissue-engineered bladder reconstruction.

PURPOSE: Enterocystoplasty is adopted for patients requiring bladder augmentation, but significant long-term complications highlight need for alternatives. We established a protocol for creating a natural-derived bladder extracellular matrix (BEM) for developing tissue-engineered bladder, and investigated its structural and functional characteristics. METHODS: Porcine bladders were de-cellularised with a dynamic detergent-enzymatic treatment using peristaltic infusion. Samples and fresh controls were evaluated using histological staining, ultrastructure (electron microscopy), collagen, glycosaminoglycans and DNA quantification and biomechanical testing. Compliance and angiogenic properties (Chicken chorioallantoic membrane [CAM] assay) were evaluated. T test compared stiffness and glycosaminoglycans, collagen and DNA quantity. p value of < 0.05 was regarded as significant. RESULTS: Histological evaluation demonstrated absence of cells with preservation of tissue matrix architecture (collagen and elastin). DNA was 0.01 µg/mg, significantly reduced compared to fresh tissue 0.13 µg/mg (p < 0.01). BEM had increased tensile strength (0.259 ± 0.022 vs 0.116 ± 0.006, respectively, p < 0.0001) and stiffness (0.00075 ± 0.00016 vs 0.00726 ± 0.00216, p = 0.011). CAM assay showed significantly increased number of convergent allantoic vessels after 6 days compared to day 1 (p < 0.01). Urodynamic studies showed that BEM maintains or increases capacity and compliance. CONCLUSION: Dynamic detergent-enzymatic treatment produces a BEM which retains structural characteristics, increases strength and stiffness and is more compliant than native tissue. Furthermore, BEM shows angiogenic potential. These data suggest the use of BEM for development of tissue-engineered bladder for patients requiring bladder augmentation.

Assisted Reproductive Technology and Anorectal Malformation: A Single-Center Experience.

Background: Assisted reproductive technologies (ART) are becoming widespread, accounting for approximately 2% of all births in the western countries. Concerns exist on the potential association of ART with congenital anomalies. Few studies have addressed if a relationship exists between ART and the development of anorectal malformation (ARM). Our aim was to analyze the relationship between ARM and ART. Methods: Single-center retrospective case control study of all patients treated for ARM between 2010 and 2017. Patients with bronchiolitis treated since 2014 were used as controls. Variables analyzed include the following: prevalence of ART, gestational age, birth weight, and maternal age. Patients with ARM born after ART were also compared with those naturally conceived for disease complexity. Fisher's exact and Mann-Whitney U-tests were used as appropriate. Results: Three hundred sixty-nine patients were analyzed (143 cases and 226 controls). Prevalence of ART was significantly higher in ARM patients than in controls [7.6 vs. 3.0%; odds ratio: 2.59 (95% CI, 0.98-0.68); p = 0.05]. Among ARM patients, incidence of VACTERL association (17%) is more frequent in ART babies. Conclusion: Patients with ARM were more likely to be conceived following ART as compared with controls without congenital anomalies. Disease complexity of patients with ARM born after ART seems greater that those born after nonassisted conception.

Operative Management of Neonatal Lymphatic Malformations: Lesson Learned From 57 Consecutive Cases.

Aim of the study: Lymphatic malformations (LMs) are rare entities, sometimes difficult to treat, that may be life-threatening when intricately connected to airway structures. Invasive treatments are occasionally required, with sclerotherapy considered the treatment of choice and surgery as a second-line approach. The aim of the present study was to evaluate our multidisciplinary team experience in treating newborns affected by LMs requiring operative management, while defining early outcomes. Methods: Retrospective review of all consecutive patients admitted for LMs requiring operative management between January 2000 and January 2019. Patients were mainly characterized based on anatomical district of the LM (and further stratified based on the development of respiratory distress), need for tracheostomy, number of sclerotherapies, indication for surgery, and residual disease beyond the 1st year. Morbidity and mortality were also evaluated. Fisher exact test and Mann-Whitney test were used as appropriate. Statistical significance was set at p < 0.05. Results: Fifty-seven patients were included in the study, 36 with cervicofacial and/or mediastinal LMs and 21 with LMs of other anatomical districts. Due to the risk of developing respiratory distress at birth, patients with cervicofacial and/or mediastinal LMs were divided into two groups (8/36 group A vs. 28/36 group B). Group A patients are at higher risk for tracheostomy (7/8 group A vs. 1/28 group B, p = 0.0001) and more often require surgical reduction of the residual lymphatic abnormality (5/8 group A vs. 4/28 group B, p = 0.013). They also require sclerotherapies more often, but the difference is not statistically significant (8/8 group A vs. 19/28 group B, p = 0.15). Patients with cervicofacial/mediastinal LMs frequently suffer from persistent residual disease beyond the 1st year of life, significantly more often in group A (7/8 group A vs. 12/28 group B, p = 0.043). Conclusion: LMs are rare conditions with potential life-threatening behavior. Their intrinsic clinical complexity requires a multidisciplinary approach to the affected patients. Planning a long-term follow-up is essential because of the late-term problems those patients may experience.

Predictive value of spinal bone anomalies for spinal cord abnormalities in patients with anorectal malformations.

AIM: To evaluate the correlation between sacral/vertebral anomalies and spinal cord anomalies (SCA) on MRI, in patients with anorectal malformation (ARM). METHODS: Patients with ARM consecutively treated between January 1999 and August 2019 were included. Radiological imaging of sacrum and spine were retrospectively analyzed and correlated to the presence of SCA at MRI. Fisher's exact test and X2 test were used as appropriate; p<0.05 was considered statistically significant. RESULTS: 348 patients with ARM were enrolled in the study, 147 presented SCA at MRI. 144 patients showed spinal bone anomalies, isolated vertebral and sacral anomalies were found in 17,6% and 35% respectively. Higher level of ARM was associated with a significant higher prevalence of sacral and vertebral anomalies. A significant correlation was found between the "level" of ARM and the presence of SCA (p<0.05). Sacral anomalies were significantly correlated with the presence of SCA at MRI (p<0.05). SCA were found in 70% of patients with vertebral anomalies (VA) and in 76% of patients with sacral anomalies. The presence of multiple malformations (vertebral and sacral anomalies) are strictly related to the presence of SCA. However, the absence of spinal bone anomalies does not exclude the presence of SCA. SD was the most represented type of SCA (n=94/147), of those 96% had fatty filum. Neurological or neurourological symptoms were detected in 11,5% patients (n=17) with SCA and required neurosurgical intervention. CONCLUSIONS: Our data confirm the strong relation between sacral or vertebral anomalies and SCA. However, in our series also patients without sacral/vertebral anomalies had SCA at MRI. Our results suggest that, despite the presence or absence of spinal anomalies, spinal cord MRI should be performed in all children with ARM, to allow a correct multidisciplinary follow-up and treatment. In fact, most patients with spinal bone and SCA are asymptomatic, but could develop clinical manifestations during their growth.

Impact of the associated anorectal malformation on the outcome of spinal dysraphism after untethering surgery.

PURPOSE: To analyze the outcome after untethering surgery in patients with spinal dysraphism (SD), with or without associated anorectal malformation (ARM). METHODS: Patients operated on for SD, with (Group A) or without (Group B) associated ARM (1999-2015), were included. The post-operative outcome was analyzed in the two groups in terms of improving of clinical symptoms (neuro-motor deficits, bladder dysfunction, bowel dysfunction) and of instrumental examinations (urodynamics, bladder ultrasound, neurophysiology). Fisher's exact test and χ2 test were used as appropriate; p < 0.05 was considered statistically significant. MAIN RESULTS: Ten patients in Group A and 24 in Group B were consecutively treated. One patient was lost at follow up. Six patients (25%) in Group B underwent prophylactic surgery. The analysis of the pre-operative symptoms in the two groups showed that a significantly higher number of patients in group A needed bowel management and presented with neuro-motor deficits, compared to group B (p = 0.0035 and p = 0.04, respectively). Group A showed a significant post-operative neuro-motor improvement as compared to group B (p = 0.002). CONCLUSIONS: Based on our results, untethering seems to be effective in neuro-motor symptoms in selected patients with ARM. In ARM patients, untethering surgery does not seem to benefit intestinal and urinary symptoms. The presence of the associated ARM does not seem to impact the medium-term outcome of patients operated for SD.

Pediatric Intestinal Rehabilitation and Transplantation Registry: Initial Report from a European Collaborative Registry.

INTRODUCTION: Short bowel syndrome (SBS) is the main cause of intestinal failure (IF) in the pediatric population. To promote the standardization of care of these patients, the registry of Pediatric Intestinal Rehabilitation and Transplantation (PIRAT) has been established. The aim of this study is to describe patients with IF using PIRAT database. MATERIALS AND METHODS: Data from two tertiary care European referral Centers registered in PIRAT (https://www.studeon.eu/pirat) were analyzed (1994-2015). Neonatal SBS-related IF was defined as need for parenteral nutrition (PN) to sustain life and growth for more than 75 days, after extensive bowel resection during neonatal period. Data included patient demographics, disease at birth, residual small intestine, and intestinal autonomy (PN on/off). RESULTS: In this study, 114 children with SBS-related IF were identified (male 60%). Median gestational age was 35.3 weeks (interquartile range [IQR]: 33.0-38.0); median birth weight was 2,440 g (IQR: 1,700-2,990). The main causes of SBS were intestinal atresia in 31 (27%), midgut volvulus in 29 (25%), necrotizing enterocolitis in 23 (20%), and gastroschisis in 12 (11%). Nine (7.9%) patients died on PN (six sepsis, two IF-associated liver disease, and one multiorgan failure). Median residual small bowel length was 46 cm (IQR: 13.0-92.5). Ileocecal valve was resected in 48 patients (42%). Intestinal autonomy was achieved in 68% patients. CONCLUSION: We present the web-based registry PIRAT and the first results of patients with IF registered from two European Centers. PIRAT could give the opportunity to create a dedicated international network (IF-net) to standardize, improve, and spread the therapeutic paths for the rare and heterogeneous condition of SBS-related IF.

Embryological and clinical implications of the association between anorectal malformations and spinal dysraphisms.

PURPOSE: To describe the association of anorectal malformation (ARM) and spinal dysraphism (SD) in terms of impact on the management of SD and embryogenetic implications. METHODS: Patients with SD associated with (A) or without (B) ARM were included. The two groups were further divided into operated on (A1/B1) or not (A2/B2) for SD. Groups A and B were compared for type of SD (embryogenetic classification) and prevalence of neurosurgery; Groups A1 vs. A2 for type of ARM (Wingspread classification); Groups A1 vs. B1 for age at neurosurgery, neurophysiology, and clinical symptoms. MAIN RESULTS: One hundred twenty-one patients with SD, 83 with and 38 without ARM were consecutively treated (1999-2015). Group A was associated only with SDs developing after primary neurulation, corresponding to the period of cloacal septation and organogenesis (p = 0.0007). Untethering surgery was significantly less frequent in Group A (p < 0.0001 and p = 0.04, respectively). Higher ARMs were not associated with increased risk for neurosurgery. No other significant differences were detected. CONCLUSIONS: In our series, ARMs were associated only with SD developing after primary neurulation, suggesting a single insult leading to both SD and the associated ARM. Neurosurgery is indicated less frequently in patients with ARM-associated SD, despite the similar preoperative clinical features.

Long-term cryopreservation of decellularised oesophagi for tissue engineering clinical application.

Oesophageal tissue engineering is a therapeutic alternative when oesophageal replacement is required. Decellularised scaffolds are ideal as they are derived from tissue-specific extracellular matrix and are non-immunogenic. However, appropriate preservation may significantly affect scaffold behaviour. Here we aim to prove that an effective method for short- and long-term preservation can be applied to tissue engineered products allowing their translation to clinical application. Rabbit oesophagi were decellularised using the detergent-enzymatic treatment (DET), a combination of deionised water, sodium deoxycholate and DNase-I. Samples were stored in phosphate-buffered saline solution at 4°C (4°C) or slow cooled in medium with 10% Me2SO at -1°C/min followed by storage in liquid nitrogen (SCM). Structural and functional analyses were performed prior to and after 2 and 4 weeks and 3 and 6 months of storage under each condition. Efficient decellularisation was achieved after 2 cycles of DET as determined with histology and DNA quantification, with preservation of the ECM. Only the SCM method, commonly used for cell storage, maintained the architecture and biomechanical properties of the scaffold up to 6 months. On the contrary, 4°C method was effective for short-term storage but led to a progressive distortion and degradation of the tissue architecture at the following time points. Efficient storage allows a timely use of decellularised oesophagi, essential for clinical translation. Here we describe that slow cooling with cryoprotectant solution in liquid nitrogen vapour leads to reliable long-term storage of decellularised oesophageal scaffolds for tissue engineering purposes.

Multicenter retrospective study on management and outcome of newborns affected by surgical necrotizing enterocolitis.

BACKGROUND: Necrotizing enterocolitis (NEC) is the most common surgical emergency in newborns and it is still a leading cause of death despite the improvements reached in the management of the critically ill neonate. The purpose of this study was to evaluate risk factors, surgical treatments and outcome of surgical NEC. METHODS: We retrospectively evaluated a multicentric group of 184 patients with surgical NEC over a period of 5 years (2008-2012). Indications to operation were modified NEC Bell stages IIIA or IIIB. The main outcome was measured in terms of survival and postsurgical complications. RESULTS: Data on 184 patients who had a surgical NEC were collected. The majority of patients (153) had a primary laparotomy (83%); 10 patients had peritoneal drainage insertion alone (5%) and 21 patients had peritoneal drainage followed by laparotomy (12%). Overall mortality was 28%. Patients with lower gestational age (P=0.001), lower birth weight (P=0.001), more extensive intestinal involvement (P=0.002) and cardiac diseases (P=0.012) had a significantly higher incidence of mortality. There was no statistically significant association between free abdominal air on the X-ray and mortality (P=0.407). Mortality in the drainage group was 60%, in the laparotomy group and drainage followed by laparotomy group was of 23-24% (P=0.043). There was a high incidence of stenosis (28%) in the drainage group (P=0.002). On multivariable regression, lower birth weight, feeding, bradycardia-desaturation and extent of bowel involvement were independent predictors of mortality. CONCLUSIONS: Laparotomy was the most frequent method of treatment (83%). Primary laparotomy and drainage with laparotomy groups had similar mortalities (23-24%), while the drainage alone treatment cohort was associated with the highest mortality (60%) with statistical value (P=0.043). Consequently laparotomy is highly protective in terms of survival rate. Stenosis seemed to be statistically associated with drainage. These findings could discourage the use of peritoneal drainage versus a primary laparotomy whenever the clinical conditions of patients allow this procedure.

Anorectal malformations associated spinal cord anomalies.

PURPOSE: The present study aims to identify clinical and pathological factors that can predict the risk of spinal cord anomalies (SCA) in patients with anorectal malformations (ARM), the need for neurosurgery, and to define the impact of SCA on the outcome of patients with ARM. METHODS: A 16-year retrospective analysis of all patients treated at a single tertiary children's Hospital with diagnosis of ARM. Data were collected to assess the impact of defined clinical characteristics on prevalence of SCA (detected at MRI). Children surgically treated or not for SCA were compared for age, clinical symptoms and type of anomalies at surgery or at last follow-up, respectively. Moreover, patients with intermediate/high ARMs, with or without SCA were compared for neurogenic bladder (NB), constipation, soiling and need for bowel management (BM). RESULTS: Two hundred and seventy-five children were treated for ARM in the study period, 142 had spinal MRI that showed SCA in 85. Patients with SCA had significantly higher prevalence of preterm birth (p < 0.05), cardiac anomalies (p = 0.02), vertebral anomalies (p = 0.0075), abnormal sacrum (p < 0.0001), and VACTERL association (p = 0.0233). Ten patients were surgically treated for SCA. The prevalence of neurological bladder and neuro-motor deficits, of vertebral and genital anomalies, particularly cryptorchidism, was significantly higher in the operated group (p < 0.01, for each analysis). In patients with intermediate/high ARMs, no significant difference was observed between those with or without SCA, in terms of prevalence of NB, intestinal function and need for BM. CONCLUSIONS: In patients with ARM, factors that can predict a higher prevalence of SCA and also determine an increased indication to neurosurgery may be identified. SCA by itself does not seem to affect the functional prognosis of children with intermediate/high ARM. These data may help physicians in stratifying the clinical and diagnostic pathway of patients with ARM.

High contrast microstructural visualization of natural acellular matrices by means of phase-based x-ray tomography.

Acellular scaffolds obtained via decellularization are a key instrument in regenerative medicine both per se and to drive the development of future-generation synthetic scaffolds that could become available off-the-shelf. In this framework, imaging is key to the understanding of the scaffolds' internal structure as well as their interaction with cells and other organs, including ideally post-implantation. Scaffolds of a wide range of intricate organs (esophagus, lung, liver and small intestine) were imaged with x-ray phase contrast computed tomography (PC-CT). Image quality was sufficiently high to visualize scaffold microarchitecture and to detect major anatomical features, such as the esophageal mucosal-submucosal separation, pulmonary alveoli and intestinal villi. These results are a long-sought step for the field of regenerative medicine; until now, histology and scanning electron microscopy have been the gold standard to study the scaffold structure. However, they are both destructive: hence, they are not suitable for imaging scaffolds prior to transplantation, and have no prospect for post-transplantation use. PC-CT, on the other hand, is non-destructive, 3D and fully quantitative. Importantly, not only do we demonstrate achievement of high image quality at two different synchrotron facilities, but also with commercial x-ray equipment, which makes the method available to any research laboratory.

VACTERL association in anorectal malformation: effect on the outcome.

PURPOSE: Anorectal malformations (ARM) can commonly occur in association with other congenital anomalies or as part of the combined anomaly. The present study aims to assess the outcome of patients with ARM and patients with ARM in VACTERL association. METHODS: A 12-year retrospective analysis of all patients treated at a single tertiary children's institution with a diagnosis of ARM. We identified and compared patients with ARM to those with ARM in VACTERL association (3 or more anomalies). Data were collected for both groups to assess type of ARM, urinary incontinence (UI), constipation, soiling, dietary/laxative treatment, bowel management (BM) and surgical complications. Type of lesion and clinical outcomes were classified according to Krickenbeck International classification. Patients lost to follow-up, dead or not yet toilet-trained (or <4 years old) were excluded. RESULTS: One hundred ninety-eight patients were identified, 174 enrolled in the study. Lesions were classified for each study group (VACTERL- vs VACTERL+) as perineal fistulas (36.4 vs 9.7%, p = 0.0028), rectourethral fistulas (prostatic and bulbar) (23.1 vs 38.7%, p = ns), rectovesical fistulas (3.5 vs 9.7%, p = ns), rectovestibular fistulas (19.6 vs 22.6%, p = ns), cloacal malformations (4.9 vs 9.7%, p = ns), no fistula (4.9 vs 3.2%, p=), others (7.7 vs 6.4%, p = ns). The frequency of both dietary/laxative treatment and BM, as well as surgical complications were significantly higher in patients with VACTERL. CONCLUSIONS: The coexistence of VACTERL anomalies negatively affects not only the surgical outcome but also the bowel functioning. Therefore, a dedicated follow-up is strongly recommended. Further studies are needed to assess if this has an impact on the quality of life of these patients.

Spinal ultrasound in patients with anorectal malformations: is this the end of an era?

PURPOSE: Even if lumbar magnetic resonance imaging (MRI) is considered the gold standard in the diagnosis of occult spinal dysraphism (SD) in patients with anorectal malformations (ARMs), spinal ultrasound (US) performed up to 5 months of life have been largely used as a screening test. The aim of the present study was to evaluate the accuracy in terms of sensibility and specificity of neonatal US to detect occult SD in patients with ARMs. METHODS: Retrospective analysis of all patients treated for ARMs between 1999 and 2013 at our institution who underwent both spinal US (up to 5 months of life) and MRI. Sensibility and specificity have been calculated for US based on MRI results. RESULTS: Of 244 patients treated for ARMs at our institution, 82 (34 females, 48 males) underwent both the imaging studies and have been included in this study. ARMs types were: anal stenosis (7), recto-vestibular fistula (19), recto-perineal fistula (3) and cloaca (5) in female and imperforate anus (7) recto-perineal fistula (14), recto-urethral fistula (22), recto-vesical fistula (5) in males. Forty-seven patients (57, 3 % of total, 18 females, 29 males) had some occult SD (tethered spinal cord, spinal lipoma, syringomyelia) at MRI. Only 7 (14, 8 %) patients of those with spinal anomalies at MRI had pathological US studies. In our population, sensibility and specificity of US for diagnosis of occult SD were, respectively, 14, 8 and 100 %. CONCLUSION: Since it is well known that a screening test must have a high sensibility, our data suggest that spinal ultrasound is not suitable as a screening test for occult spinal dysraphism in patients with ARMs. Furthermore, we strongly advise against the use of US as a screening test for spinal dysraphism to prevent a false sense of security in physician and patients' families.

A decellularization methodology for the production of a natural acellular intestinal matrix.

Successful tissue engineering involves the combination of scaffolds with appropriate cells in vitro or in vivo. Scaffolds may be synthetic, naturally-derived or derived from tissues/organs. The latter are obtained using a technique called decellularization. Decellularization may involve a combination of physical, chemical, and enzymatic methods. The goal of this technique is to remove all cellular traces whilst maintaining the macro- and micro-architecture of the original tissue. Intestinal tissue engineering has thus far used relatively simple scaffolds that do not replicate the complex architecture of the native organ. The focus of this paper is to describe an efficient decellularization technique for rat small intestine. The isolation of the small intestine so as to ensure the maintenance of a vascular connection is described. The combination of chemical and enzymatic solutions to remove the cells whilst preserving the villus-crypt axis in the luminal aspect of the scaffold is also set out. Finally, assessment of produced scaffolds for appropriate characteristics is discussed.

Human amniotic fluid stem cell differentiation along smooth muscle lineage.

Functional smooth muscle engineering requires isolation and expansion of smooth muscle cells (SMCs), and this process is particularly challenging for visceral smooth muscle tissue where progenitor cells have not been clearly identified. Herein we showed for the first time that efficient SMCs can be obtained from human amniotic fluid stem cells (hAFSCs). Clonal lines were generated from c-kit(+) hAFSCs. Differentiation toward SM lineage (SMhAFSCs) was obtained using a medium conditioned by PDGF-BB and TGF-ß1. Molecular assays revealed higher level of α smooth muscle actin (α-SMA), desmin, calponin, and smoothelin in SMhAFSCs when compared to hAFSCs. Ultrastructural analysis demonstrated that SMhAFSCs also presented in the cytoplasm increased intermediate filaments, dense bodies, and glycogen deposits like SMCs. SMhAFSC metabolism evaluated via mass spectrometry showed higher glucose oxidation and an enhanced response to mitogenic stimuli in comparison to hAFSCs. Patch clamp of transduced hAFSCs with lentiviral vectors encoding ZsGreen under the control of the α-SMA promoter was performed demonstrating that SMhAFSCs retained a smooth muscle cell-like electrophysiological fingerprint. Eventually SMhAFSCs contractility was evident both at single cell level and on a collagen gel. In conclusion, we showed here that hAFSCs under selective culture conditions are able to give rise to functional SMCs.

Preservation of micro-architecture and angiogenic potential in a pulmonary acellular matrix obtained using intermittent intra-tracheal flow of detergent enzymatic treatment.

Tissue engineering of autologous lung tissue aims to become a therapeutic alternative to transplantation. Efforts published so far in creating scaffolds have used harsh decellularization techniques that damage the extracellular matrix (ECM), deplete its components and take up to 5 weeks to perform. The aim of this study was to create a lung natural acellular scaffold using a method that will reduce the time of production and better preserve scaffold architecture and ECM components. Decellularization of rat lungs via the intratracheal route removed most of the nuclear material when compared to the other entry points. An intermittent inflation approach that mimics lung respiration yielded an acellular scaffold in a shorter time with an improved preservation of pulmonary micro-architecture. Electron microscopy demonstrated the maintenance of an intact alveolar network, with no evidence of collapse or tearing. Pulsatile dye injection via the vasculature indicated an intact capillary network in the scaffold. Morphometry analysis demonstrated a significant increase in alveolar fractional volume, with alveolar size analysis confirming that alveolar dimensions were maintained. Biomechanical testing of the scaffolds indicated an increase in resistance and elastance when compared to fresh lungs. Staining and quantification for ECM components showed a presence of collagen, elastin, GAG and laminin. The intratracheal intermittent decellularization methodology could be translated to sheep lungs, demonstrating a preservation of ECM components, alveolar and vascular architecture. Decellularization treatment and methodology preserves lung architecture and ECM whilst reducing the production time to 3 h. Cell seeding and in vivo experiments are necessary to proceed towards clinical translation.

Discarded human kidneys as a source of ECM scaffold for kidney regeneration technologies.

In the United States, more than 2600 kidneys are discarded annually, from the total number of kidneys procured for transplant. We hypothesized that this organ pool may be used as a platform for renal bioengineering and regeneration research. We previously showed that decellularization of porcine kidneys yields renal extracellular matrix (ECM) scaffolds that maintain their basic components, support cell growth and welfare in vitro and in vivo, and show an intact vasculature that, when such scaffolds are implanted in vivo, is able to sustain physiological blood pressure. The purpose of the current study was to test if the same strategy can be applied to discarded human kidneys in order to obtain human renal ECM scaffolds. The results show that the sodium dodecylsulfate-based decellularization protocol completely cleared the cellular compartment in these kidneys, while the innate ECM framework retained its architecture and biochemical properties. Samples of human renal ECM scaffolds stimulated angiogenesis in a chick chorioallantoic membrane assay. Importantly, the innate vascular network in the human renal ECM scaffolds retained its compliance. Collectively, these results indicate that discarded human kidneys are a suitable source of renal scaffolds and their use for tissue engineering applications may be more clinically applicable than kidneys derived from animals.

Skeletal muscle tissue engineering: which cell to use?

Tissue-engineered skeletal muscle is urgently required to treat a wide array of devastating congenital and acquired conditions. Selection of the appropriate cell type requires consideration of several factors which amongst others include, accessibility of the cell source, in vitro myogenicity at high efficiency with the ability to maintain differentiation over extended periods of time, susceptibility to genetic manipulation, a suitable mode of delivery and finally in vivo differentiation giving rise to restoration of structural morphology and function. Potential stem-progenitor cell sources include and are not limited to satellite cells, myoblasts, mesoangioblasts, pericytes, muscle side-population cells, CD133(+) cells, in addition to embryonic stem cells, mesenchymal stem cells, amniotic fluid stem cells and induced pluripotent stem (iPS) cells. The relative merits and inherent limitations of these cell types within the field of tissue-engineering are discussed in the light of current research. Recent advances in the field of iPS cells should bear the fruits for some exciting developments within the field in the forthcoming years.

Detergent enzymatic treatment for the development of a natural acellular matrix for oesophageal regeneration.

PURPOSE: Tissue engineering of the oesophagus has been proposed as a therapeutic alternative to organ transplantation. We previously demonstrated that a detergent enzymatic treatment (DET) is a valid method to obtain an acellular matrix with preservation of the native architecture. In this study, we aimed to develop a natural acellular matrix from pig oesophagus, as a valid framework for oesophageal replacement. METHODS: Pig oesophagi (n = 4) were decellularized with continuous luminal infusion of DET. To evaluate the efficiency of the decellularization, samples were assessed by histology and DNA quantification. Moreover, the ultra-structural characteristics of the acellular matrix were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). RESULTS: Decellularization of the oesophagus was achieved after three cycles of DET. Histological analysis showed the maintenance of tissue matrix architecture with absence of cellular elements, verified by measurement of DNA. SEM and TEM analysis confirmed preservation of the ultra-structural characteristics of the native tissue. CONCLUSIONS: Oesophageal acellular matrix can be successfully obtained by decellularization of pig oesophagus using a gentle DET via the oesophageal lumen. This decellularization method preserves the ultrastructure of the native tissue and could represent the basis for a tissue-engineered oesophagus.