Introduction: Pancreatic islet transplantation is one of the methods of treating patients with T1D. However, for the procedure to be successful, the high quality of the implanted islets is of key importance for a successful islet transplant. Following islet isolation, it has been shown that mainly β-cells undergo apoptosis due to vascular loss and hypoxia. The cellular stresses to which islets are subjected during isolation (for example disturbance of the cell-matrix relationship). Appropriate storage conditions for insulated islands are of key importance for their functionality. The most common method of islet storage is the introduction into a suspension culture. However, because these are micro organs, the storage of pancreatic islets is a more accurate term. Therefore, this study aimed to demonstrate whether for pancreatic islets it is better to cultivate them in standard conditions (37^oC; 5% CO₂), or maybe stored them at 4^oC.

Material: The research material was porcine pancreatic islets. Islets were isolated from the native organ using collagenase and a Ricordi chamber. After isolation, the material was divided into 4 research groups: 1. control (islands suspended in CMRL 1066 medium) - traditional breeding conditions (temperature 37^oC; 5% CO₂); 2. CMRL 1066 suspended islets stored at 4^oC; 3. Islets in CMRL 1066 medium with the addition of dECM (decellularized extracellular matrix) - in traditional culture conditions; 4. Islets in CMRL 1066 supplemented with dECM stored at 4^oC. Each variant was tested in 3 replicates and each trial was 3000iEq. Additionally, each tested variant was tested on pancreatic islets that were cleaned or not immediately after isolation.

Results: The research showed that the storage temperature, reduced to 4^oC, and the addition of ECM significantly influenced the functionality of the islets. This variant tested (uncleaned islands) showed functionality even 5 days after isolation. On the other hand, islets incubated at 37°C without the addition of dECM showed no functionality after 2 days of the experiment. The remaining variants showed a gradual loss of functionality. However, the 4^oC variant was better in each case.

Conclusion: Pancreatic islets, as micro organs with their vascularization, need appropriate storage conditions after isolation to ensure their proper functioning. Based on these studies, it was shown that the islands should be stored and not cultivated as single-cell lines. In addition, the addition of dECM allows for the recreation of the matrix-cell environment, which is appropriate storage conditions - corresponding to the native environment.