The novel use of small intestinal submucosal matrix for chest wall reconstruction following Ewing's tumour resection

Pioneering a paradigm shift in tissue engineering and regeneration with polysaccharides and proteins-based scaffolds: A comprehensive review

In the realm of modern medicine, tissue engineering and regeneration stands as a beacon of hope, offering the promise of restoring form and function to damaged or diseased organs and tissues. Central to this revolutionary field are biological macromolecules-nature's own blueprints for regeneration. The growing interest in bio-derived macromolecules and their composites is driven by their environmentally friendly qualities, renewable nature, minimal carbon footprint, and widespread availability in our ecosystem. Capitalizing on these unique attributes, specific composites can be tailored and enhanced for potential utilization in the realm of tissue engineering (TE). This review predominantly concentrates on the present research trends involving TE scaffolds constructed from polysaccharides, proteins and glycosaminoglycans. It provides an overview of the prerequisites, production methods, and TE applications associated with a range of biological macromolecules. Furthermore, it tackles the challenges and opportunities arising from the adoption of these biomaterials in the field of TE. This review also presents a novel perspective on the development of functional biomaterials with broad applicability across various biomedical applications.

Chest wall osteochondroma resection with biologic acellular bovine dermal mesh reconstruction in pediatric hereditary multiple exostoses: A case report and review of literature

BACKGROUND

Hereditary multiple exostoses is a rare genetic disorder characterized by the growth of multiple osteochondromas affecting primarily long bones. Chest wall lesions may represent a challenge, particularly in pediatric patients. Pain is a common manifestation. However, life-threatening complications can result from direct involvement of adjacent structures. Surgical resection with appropriate reconstruction is often required.

CASE SUMMARY

A 5-year-old male who was diagnosed with hereditary multiple exostoses presented with significant pain from a large growing chest wall exostosis lesion. After appropriate preoperative investigations, he underwent surgical resection with reconstruction of his chest wall using a biologic bovine dermal matrix mesh.

CONCLUSION

Resection of chest wall lesions in children represents a challenge. Preoperative planning to determine the appropriate reconstruction strategy is essential.

Application of biomaterials and tissue engineering in bladder regeneration

The primary functions of the bladder are storing urine under low and stable pressure and micturition. Various forms of trauma, tumors, and iatrogenic injuries can cause the loss of or reduce bladder function or capacity. If such damage is not treated in time, it will eventually lead to kidney damage and can even be life-threatening in severe cases. The emergence of tissue engineering technology has led to the development of more possibilities for bladder repair and reconstruction, in which the selection of scaffolds is crucial. In recent years, a growing number of tissue-engineered bladder scaffolds have been constructed. Therefore, this paper will discuss the development of tissue-engineered bladder scaffolds and will further analyze the limitations of and challenges encountered in bladder reconstruction.

Decellularization of Small Intestinal Submucosa

Small intestinal submucosa (SIS) is the most studied extracellular matrix (ECM) for repair and regeneration of different organs and tissues. Promising results of SIS-ECM as a vascular graft, led scientists to examine its applicability for repairing other tissues. Overall results indicated that SIS grafts induce tissue regeneration and remodeling to almost native condition. Investigating immunomodulatory effects of SIS is another interesting field of research. SIS can be utilized in different forms for multiple clinical and experimental studies. The aim of this chapter is to investigate the decellularization process of SIS and its common clinical application.

Primary paediatric chest wall tumours necessitating surgical management

INTRODUCTION

Limited literature exists on oncological chest wall reconstruction in the paediatric population, with the field still largely undecided on the best surgical reconstructive techniques to employ. The use of biological grafts/meshes is gaining popularity in certain adult surgical procedures but their use in paediatric procedures is rarely reported in the literature. We present the outcomes of our institution's multidisciplinary approach to managing paediatric chest wall tumours as well as our experience with the use of biological grafts for chest wall reconstruction following oncological resections.

METHODS

Data were analysed retrospectively from eight paediatric patients who were treated for primary chest wall tumours between 2010 and 2018.

RESULTS

The tumours comprised two lipoblastomas, three Ewing's sarcomas, an undifferentiated sarcoma with osteosarcomatous differentiation, a high grade undifferentiated sarcoma and a myofibroma. Seven of the eight patients underwent chest wall reconstruction with a biological graft. There were no postoperative mortalities and no evidence of recurrence in any of the patients in the series. No further chest wall operations were required and there were no postoperative infection related complications.

CONCLUSIONS

We support the use of biological grafts for chest wall reconstruction after oncological resections and maintain that a multidisciplinary approach is essential for the management of paediatric chest wall tumours.

Hybrid nanocomposite as a chest wall graft with improved integration by adipose-derived stem cells

Surgery of the chest wall is potentially required to cover large defects after  removal of malignant tumours. Usually, inert and non-degradable Gore-Tex serves to replace the missing tissue. However, novel biodegradable materials combined with stem cells are available that stimulate the healing. Based on poly-lactic-co-glycolic acid and amorphous calcium phosphate nanoparticles (PLGA/aCaP) and pure PLGA, a dual layer biodegradable hybrid nanocomposite was generated. Mouse adipose-derived stem cells were cultered on electrospun disks (ASCs of C57BL/6), and biomechanical tests were performed. The cell-seeded scaffolds were engrafted in C57BL/LY5.1 mice to serve as a chest wall substitute. Cell invasion into the bi-layered material, extent of CD45⁺ cells, inflammatory response, neo-vascularization and ECM composition were determined at 1 and 2 months post-surgery, respectively. The bi-layered hybrid nanocomposite was stable after a 2-week in vitro culture, in contrast to PLGA/aCaP without a PLGA layer. There was a complete biointegration and good vascularization in vivo. The presence of ASCs attracted more CD45⁺ cells (hematopoietic origin) compared to cell-free scaffolds. Inflammatory reaction was similar for both groups (±ASCs) at 8 weeks. A bi-layered hybrid nanocomposite fabricated of electrospun PLGA/aCaP and a reinforcing layer of pristine PLGA is an ideal scaffold for chest wall reconstruction. It is stable and allows a proper host tissue integration. If ASCs are seeded, they attract more CD45⁺ cells, supporting the regeneration process.

Naturally-Derived Biomaterials for Tissue Engineering Applications

Naturally-derived biomaterials have been used for decades in multiple regenerative medicine applications. From the simplest cell microcarriers made of collagen or alginate, to highly complex decellularized whole-organ scaffolds, these biomaterials represent a class of substances that is usually first in choice at the time of electing a functional and useful biomaterial. Hence, in this chapter we describe the several naturally-derived biomaterials used in tissue engineering applications and their classification, based on composition. We will also describe some of the present uses of the generated tissues like drug discovery, developmental biology, bioprinting and transplantation.

Thoracic wall reconstruction with bioabsorbable plates in pediatric malignant thoracic wall tumors

AIM

Childhood malignant chest wall tumors may require extensive surgical resection and reconstruction with musculoskeletal flaps or non-resorbable prosthetic materials. Implant-related complications and scoliosis often occur. This study analyzes the outcomes of chest wall reconstruction using resorbable plates as an alternative approach.

METHODS

Retrospective review (2007-2015) of patients who underwent resection of malignant primary chest wall tumors in 2 tertiary pediatric centers. Reconstruction was performed using copolymer (l-lactic and glycolic acid) plates, fixed to the ribs and surrounding structures with copolymer screws and/or polyglactin sutures.

RESULTS

Eight patients aged 10.6+2.6years were treated. There were no operative complications, and implant removal was not required in any case. Six patients received postoperative radiotherapy. Over follow-up (39.6months, range 9.4-78), chest wall shape was maintained in all, and there were no radiological artifacts. Three patients developed scoliosis (Cobb 17°-33°), but treatment was needed only in one, who had undergone hemivertebrectomy. There were no cases of local tumor relapse. One patient died because of metastatic spread.

CONCLUSIONS

Implantation of bioabsorbable l-lactic and glycolic acid copolymer plates with a relatively simple technique provided a rigid, stable reconstruction with only mild mid-/long-term complications. Resorbable plates may be a good alternative for pediatric chest wall reconstruction.

LEVEL OF EVIDENCE

IV.

Successful endothelialization and remodeling of a cell-free small-diameter arterial graft in a large animal model

The large number of coronary artery bypass procedures necessitates development of off-the-shelf vascular grafts that do not require cell or tissue harvest from patients. However, immediate thrombus formation after implantation due to the absence of a healthy endothelium is very likely. Here we present the successful development of an acellular tissue engineered vessel (A-TEV) based on small intestinal submucosa that was functionalized sequentially with heparin and VEGF. A-TEVs were implanted into the carotid artery of an ovine model demonstrating high patency rates and significant host cell infiltration as early as one week post-implantation. At one month, a confluent and functional endothelium was present and the vascular wall showed significant infiltration of host smooth muscle cells exhibiting vascular contractility in response to vaso-agonists. After three months, the endothelium aligned in the direction of flow and the medial layer comprised of circumferentially aligned smooth muscle cells. A-TEVs demonstrated high elastin and collagen content as well as impressive mechanical properties and vascular contractility comparable to native arteries. This is the first demonstration of successful endothelialization, remodeling, and development of vascular function of a cell-free vascular graft that was implanted in the arterial circulation of a pre-clinical animal model.

Biomatrices for bladder reconstruction

There is a demand for tissue engineering of the bladder needed by patients who experience a neurogenic bladder or idiopathic detrusor overactivity. To avoid complications from augmentation cystoplasty, the field of tissue engineering seeks optimal scaffolds for bladder reconstruction. Naturally derived biomaterials as well as synthetic and natural polymers have been explored as bladder substitutes. To improve regenerative properties, these biomaterials have been conjugated with functional molecules, combined with nanotechology, or seeded with exogenous cells. Although most studies reported complete and functional bladder regeneration in small-animal models, results from large-animal models and human clinical trials varied. For functional bladder regeneration, procedures for biomaterial fabrication, incorporation of biologically active agents, introduction of nanotechnology, and application of stem-cell technology need to be standardized. Advanced molecular and medical technologies such as next generation sequencing and magnetic resonance imaging can be introduced for mechanistic understanding and non-invasive monitoring of regeneration processes, respectively.

Prognostic risk factors for the development of scoliosis after chest wall resection for malignant tumors in children

BACKGROUND

Surgical resection of a malignant tumor of the chest wall in children may result in the development of progressive scoliosis. The aim of this study was to identify the risk factors associated with scoliosis following resection of a tumor of the chest wall and to evaluate the prevalence and characteristics of the scoliosis.

METHODS

Forty children who underwent resection of a malignant tumor of the chest wall from 1984 to 2005 were included in a multicenter, retrospective cohort study. The mean age of the patients at the time of surgery was 9.8 years (range, 0.2 to nineteen years). Resections were classified with the use of the following scheme: the number of resected ribs was noted in Roman numerals, and the level of the resection was identified by dividing the thorax into three sectors (A [anterior], B [lateral], and C [posterior]) in the horizontal plane. One to five ribs (mean, 2.3 ribs) were resected. Patients with scoliosis were compared with patients who did not have scoliosis through the use of univariate and multivariate analyses. The mean duration of follow-up was 8.5 years (range, three to twenty-three years).

RESULTS

Patients who had a tumor resection during a rapid-growth period (patient age of less than six years or between twelve and fifteen years) had a 5.8 times higher risk of scoliosis. The resection of three or more ribs in the posterior sector (C) was the primary risk factor for scoliosis, with an odds ratio of 18.9. Seventeen (43%) of the children developed scoliosis, which was convex toward the resection side without vertebral rotation in all of them.

CONCLUSIONS

The risk of scoliosis following the resection of a primary malignant tumor of the chest wall in children was shown to be higher when resection was performed during a rapid-growth period and when the resection involved three or more ribs in the posterior sector.

Understanding roles of porcine small intestinal submucosa in urinary bladder regeneration: identification of variable regenerative characteristics of small intestinal submucosa

Neuropathic bladders are the result from damages to the central or peripheral nervous system, and ultimately may require surgical reconstruction to increase bladder volumes and to reduce the risk of damages to the kidneys. Surgical reconstruction through bladder augmentation has traditionally been practiced using a segment of the ileum, colon, or stomach from the patient through enterocystoplasty. However, the use of gastrointestinal segments can lead to serious adverse consequences. Porcine small intestinal submucosa (SIS), a xenogeneic, acellular, biocompatable, biodegradable, and collagen-based bioscaffold is best known to encourage bladder regeneration without ex vivo cell seeding before implantation in various experimental and preclinical animal models. Although it has been demonstrated that SIS supports bladder cell growth in vitro, and SIS-regenerated bladders are histologically and functionally indistinguishable from normal functional tissues, clinical utilization of SIS for bladder augmentation has been hampered by inconsistent preclinical results. Several variables in SIS, such as the age of pigs, the region of the small intestine, and method of sterilization, can have different physical properties, biochemical characteristics, inflammatory cell infiltration, and regenerative capacity due to cellular responses in vitro and in vivo. These parameters are particularly important for bladder regeneration due to its specific biological function in urine storage. Clinical application of SIS for surgical bladder reconstruction may require graft materials to be prepared from a specific region of the small intestine, or to be further formulated or processed to provide uniform physical and biochemical properties for consistent, complete, and functional bladder regeneration.

An innovative method of pediatric chest wall reconstruction using Surgisis and swinging rib technique

PURPOSE

Herein, we describe a new surgical approach for chest wall reconstruction using a native supporting rib and Surgisis.

METHODS

A retrospective review of 3 cases from 2 tertiary pediatric health care centers presenting with chest wall defects in the neonatal period was performed. Perioperative data were collected.

RESULTS

Two chest wall deformities were diagnosed at birth (Poland syndrome and cleft sternum). One patient was diagnosed prenatally with a mediastinal mass. The first infant had absent ribs 2 through 9. He underwent chest wall reconstruction at 4 weeks of life because of difficulty weaning from ventilation related to paradoxical breathing. The hamartoma of the second asymptomatic patient was removed at 6 weeks. The third patient's V-shaped sternal defect encompassed through the upper two thirds of the sternum and was repaired at 6 months of age with intraoperative transesophageal echocardiogram monitoring. In all cases, Surgisis (collagen matrix) was used as an onlay patch. In 2 cases, a swinging rib acted supportive. Neither patient had intraoperative complications.

CONCLUSION

Surgisis is useful in pediatric chest wall reconstruction, particularly in combination with swinging ribs. The capacity for adaptation to the child's growth of this approach is crucial. Short-term safety is shown, but long-term assessment is required.

Maintenance of hepatic sinusoidal endothelial cell phenotype in vitro using organ-specific extracellular matrix scaffolds

Sinusoidal endothelial cells (SECs) are notoriously difficult to culture in vitro. SECs represent a highly specialized endothelial cell (EC) population, and traditional methods of SEC isolation from the liver initiate a process of SEC dedifferentiation. Acellular extracellular matrix (ECM) scaffolds were investigated in a physiologically relevant in vitro culture model for their ability to maintain SEC phenotype. The cell culture model used SECs only or a coculture of SECs with hepatocytes on ECM substrates derived from the liver (L-ECM), bladder (UBM-ECM), or small intestine submucosa (SIS-ECM). The effect of the ECM substrate upon SEC dedifferentiation was evaluated using scanning electron microscopy (SEM) and confocal microscopy. When SECs alone were cultured on uncoated glass slides, collagen I, UBM-ECM, or SIS-ECM, SECs showed signs of dedifferentiation after 1 day. In contrast, SECs alone cultured on L-ECM maintained their differentiated phenotype for at least 3 days, indicated by the presence of many fenestrations on SEC surface, expression of anti-rat hepatic sinusoidal endothelial cells mouse IgG MoAb (SE-1), and lack of expression of CD31. When SECs were cocultured with hepatocytes on any of the ECM scaffolds, the SECs maintained a near-normal fenestrated phenotype for at least 1 day. However, SEM revealed that the shape, size, frequency, and organization of the fenestrations varied greatly depending on ECM source. At all time points, SECs cocultured with hepatocytes on L-ECM maintained the greatest degree of differentiation. The present study demonstrated that the acellular ECM scaffold derived from the liver maintained SEC differentiation in culture longer than any of the tested substrate materials. The replacement of complex tissues and 3-dimensional organs may require specialized scaffolds to support multiple, functional cell phenotypes.