Browsing by Author "Pazmino, Carlos"
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- Development of a decellularized extracelular matrix from porcine aorta for heart valve applications in the Ross procedurePublication . Reis, Mariana S.; Rosadas, Marta; Ho, Chou I.; Sousa, Teresa; Pazmino, Carlos; Costa, João; Vervenne, Thibault; Oliveira, Ana L.; Ribeiro, Viviana P.; Mignon, ArnCardiovascular diseases are the leading cause of adult mortality worldwide, according to the World Health Organization [1]. An important surgical approach for treating diseased aortic valves is the Ross procedure, in whic the affected aortic valve is replaced with an autograft from the patient’s own pulmonary valve.
- Supercritical CO2-assisted decellularization: advanced pancreatic tissue platform for diabetes treatmentPublication . Sá, Simone C.; Pazmino, Carlos; Sá, Joana; Amorim, Sara; Ribeiro, Viviana P.; Costa, Raquel; Oliveira, Ana L.Introduction: Decellularization is a procedure that aims to remove the cellular and antigenic material of a tissue while preserving its extracellular matrix (ECM) and biological properties. Decellularized ECM offers a natural microenvironment with significant potential for use in cell-based therapies and tissue regeneration [1]. Different protocols have been employed to decellularize tissues and organs. However, many rely on solvents and detergents that compromise the bioactive signals inherent to the native tissue [2]. Thus, it is crucial to establish a method that achieves effective decellularization while maintaining the ECM biochemical integrity. Objectives: In this study, we focus on the pancreatic tissue decellularization to create a native-like matrix suitable for the delivery of functional, insulin-producing β-cells as a therapeutic approach for diabetes treatment [3]. We propose a decellularization protocol based on Supercritical CO₂ (scCO₂) technology as an innovative alternative to solvent-based methods, offering high transfer rates, diffusivity, chemical inertness, and non-toxicity [4]. Conclusions: Both decellularization protocols efficiently removed DNA and SEM confirmed ECM ultrastructure maintenance in both groups. Biochemical analysis revealed that scCO₂ decellularization slightly improves GAG’s preservation, while insoluble collagen is protocol-independent and soluble collagen remains similar in both methods. Proteomic analysis showed that traditional treatment retained more proteoglycans and SLRPs, whereas scCO₂ better preserved some basal membrane and especially elastic fiber proteins. Biocompatibility assays demonstrated that both scaffolds supported cell adhesion, viability, and proliferation. In conclusion, both protocols generate biocompatible scaffolds, with distinct ECM preservation profiles relevant for recellularization, but scCO₂ stands out for being a green technology, with a shorter effective decellularization time and reduced waste.
- Unlocking the potential of supercritical CO₂ for an efficient pancreatic tissue decellularization: a step towards an advanced cell therapyPublication . Sá, Simone C.; Pazmino, Carlos; Sá, Joana; Amorim, Sara; Ribeiro, Viviana P.; Costa, Raquel; Oliveira, Ana L.Introduction: Tissue decellularization is a procedure that removes cellular and antigenic material from specific tissues, while preserving the extracellular matrix (ECM), with conditions tailored to the tissue's properties. The decellularized ECM is a promising material for cell-based therapies or for tissue defect repair through the development of scaffolds and membranes, among others. Pancreas is an organ that regulates the glucose levels in the bloodstream, primarily through insulin secretion by endocrine pancreatic β-cells. Diabetes type 2 settles on the insufficient secretion of insulin, and the consequent increase of glucose in the body. Extensive research is being conducted to find alternatives to overcome this condition, particularly on cell-based therapies, that deliver viable and functional β-cells and restore insulin production to regulate blood glucose levels effectively. Objectives: This study aims to develop and validate a decellularization protocol for porcine pancreatic tissue using Supercritical CO₂ (scCO2) technology as an innovative alternative to solvent-based processes, offering high transfer rates, diffusivity, chemical inertness, and non-toxicity [3]. Three protocols were tested: Traditional decellularization method using detergents; scCO₂-based decellularization protocol; Hybrid protocol combining both technologies. Conclusions: Results suggest that scCO₂ is the most efficient method for porcine pancreatic tissue decellularization, reducing DNA below 50 ng/mL in four cycles and achieving near-complete removal by the fifth. The traditional + scCO₂ approach also meets the threshold in four cycles but retains more residual DNA than scCO₂. This highlights scCO₂ as a faster and more effective method, fully decellularizing tissue in 20 hours, while the traditional method takes 27 hours 30 minutes and remains incomplete.