Catheter injectable hydrogel-based scaffolds for tissue engineering applications in lung disease

Background: Chronic lung diseases, especially emphysema and pulmonary fibrosis, are the third leading cause of mortality worldwide. Their treatment includes symptom alleviation, slowing of the disease progression, and ultimately organ transplant. Regenerative medicine represents an attractive alternative. Objectives: To develop a dual approach to lung therapy by engineering a platform dedicated to both remodeling pulmonary architecture (bronchoscopic lung volume reduction) and regeneration of lost respiratory tissue (scaffold). Methods: The authors developed a hydrogel scaffold based on the natural polymers gelatin and alginate. The unique physical properties allow its injection through long catheters that pass through the working channel of a bronchoscope. The scaffold might reach the diseased area; thus, serving a dual purpose: remodeling the lung architecture as a lung volume reduction material and developing a platform for tissue regeneration to allow for cell or organoid implant. Results: The authors' novel hydrogel scaffold can be injected through long catheters, exhibiting the physical and mechanical properties necessary for the dual treatment objectives. Its bio-compatibility was analyzed on human fibroblasts and mouse mesenchymal cells. Cells injected with the scaffold through long narrow catheters exhibited at least 70% viability up to 7 days. Conclusions: The catheter-injectable gelatin-alginate hydrogel represents a new concept, which combines tissue engineering with minimal invasive procedure. It is an inexpensive and convenient to use alternative to other types of suggested scaffolds for lung tissue engineering. This novel concept may be used for additional clinical applications in regenerative medicine.