From Decellularization to Recellularization: The Future of Pancreatic Regeneration in Veterinary Medicine

Management of pancreatic disorders such as diabetes mellitus and pancreatitis continues to present significant clinical challenges in veterinary medicine. Conventional therapies primarily focus on controlling disease progression and alleviating clinical signs, while restoration of damaged pancreatic tissue remains difficult. Advances in tissue engineering have introduced a promising strategy that aims to recreate a functional pancreatic environment by combining biological scaffolds with living cells. 

At the center of this approach are two complementary processes, decellularization and recellularization. Together, they seek to preserve the pancreas' native extracellular matrix (ECM) while repopulating it with functional cells capable of restoring biological activity¹. Although these approaches remain under development, understanding their principles provides practicing veterinarians with valuable insight into the future direction of regenerative medicine. 

Building a Biological Scaffold Through Decellularization 

Decellularization is the process of removing all cellular material from an organ while preserving the three-dimensional extracellular matrix, vascular architecture, and structural proteins that provide support for future cell growth^1,2. Successful decellularization minimizes immunogenicity by eliminating cellular components while maintaining the ECM molecules responsible for cellular adhesion, migration, proliferation, and differentiation². 

Several techniques can be used individually or in combination. 

Chemical methods are the most widely employed and include acids, bases, and detergents. Acetic and peracetic acids effectively remove cellular material but may damage ECM components, while alkaline agents such as calcium hydroxide, sodium sulfide, and sodium hydroxide can reduce important growth factors, including glycosaminoglycans, leading to loss of bioactivity^1,2. 

Among chemical agents, detergents remain the preferred option because they solubilize cell membranes and facilitate removal of cellular debris^1,3. Sodium dodecyl sulfate (SDS) is particularly effective in removing residual nuclei and cytoplasmic proteins, whereas Triton X-100 acts less aggressively on tissue architecture and may be advantageous in thicker tissues^1,4. Sodium deoxycholate (SDC) also removes remaining cellular material but may produce greater disruption of native tissue architecture compared with SDS¹. 

Supporting the Process with Physical and Biological Methods 

Physical methods complement chemical protocols and include freeze–thaw cycles, mechanical agitation, immersion, and perfusion techniques⁵. Temperature-based protocols promote cell removal through repeated freezing and thawing but require careful control because excessive ice formation can damage the ECM structure. These approaches are generally more suitable for simpler tissues and are less effective in complex organs such as the pancreas¹. 

Mechanical agitation using magnetic stirrers, orbital shakers, or low-profile rollers facilitates cell lysis and removal, particularly in small tissue samples without intact vascular structures. However, these techniques alone are usually insufficient to achieve complete decellularization and are therefore combined with chemical methods¹. 

Biological approaches further enhance the process. DNases and RNases degrade residual nucleic acids after cell lysis, while chelating agents such as ethylenediaminetetraacetic acid (EDTA) and ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA) assist in separating cells from the extracellular matrix by sequestering divalent metal ions¹. These agents are typically incorporated into multi-step protocols rather than used independently. 

Recellularization: Restoring Cellular Function 

Once a scaffold has been prepared, recellularization aims to repopulate it with cultured cells capable of restoring tissue function. Successful recellularization depends on preservation of the scaffold's three-dimensional architecture, selection of appropriate cell types, efficient cell seeding techniques, and maintenance of a physiological culture environment¹. 

Functional pancreatic reconstruction requires the coordinated presence of three major cell groups: 

• Parenchymal cells responsible for organ function 

• Vascular cells that establish adequate blood supply 

• Supportive cells that maintain tissue integrity

Various cell types have been evaluated for scaffold repopulation, including pancreatic islet cells, mesenchymal stem cells, endothelial cells, endothelial progenitor cells, fibroblasts, insulinoma cells, fetal pancreatic cells, and induced pluripotent stem cells (iPSCs)^1,6,7. 

Each cell source offers unique advantages and limitations. Adult cells already possess tissue-specific functions but demonstrate limited proliferative capacity. Fetal progenitor cells exhibit excellent proliferative ability but raise ethical concerns regarding their clinical application. Stem cells have attracted considerable interest because of their capacity for extensive proliferation and differentiation into multiple cell types, making them the most frequently used cells in recellularization protocols¹. 

Therapeutic Potential for Pancreatic Disease 

The preserved pancreatic ECM offers an attractive platform for cell transplantation because it retains the structural and biochemical signals necessary for cellular survival and function⁸. Islet cells seeded within pancreatic scaffolds have demonstrated maintenance of cellular viability and function under in vitro conditions¹. 

Observations using canine pancreatic scaffolds seeded with canine and rat mesenchymal stem cells have also demonstrated cell survival and proliferation, highlighting the potential future application of these constructs in veterinary medicine for pancreatic diseases¹. While further in vivo evaluation remains necessary, these developments illustrate the growing role of regenerative strategies in pancreatic medicine. 

Practical Clinical Insights 

For practicing veterinarians, tissue engineering represents an evolving area that extends beyond laboratory science. Understanding the principles of decellularization, scaffold preservation, and recellularization provides valuable context for future regenerative therapies targeting diabetes mellitus and pancreatitis. Although these approaches are not yet part of routine clinical practice, preserving the native pancreatic extracellular matrix while restoring functional cell populations offers a promising direction for advancing treatment options in canine pancreatic disease. 

References 

1. Pantoja BT, Carvalho RC, Miglino MA, Carreira AC. The canine pancreatic extracellular matrix in diabetes mellitus and pancreatitis: its essential role and therapeutic perspective. Animals. 2023 Feb 15;13(4):684. https://www.mdpi.com/2076-2615/13/4/684 

2. Peloso A, Citro A, Oldani G, Brambilla S, Piemonti L, Cobianchi L. Bioengineering the Pancreas: Cell-on-Scaffold Technology. Scaffolds in Tissue EngineeringMaterials, Technologies and Clinical Applications. 2017 Dec 13;293. https://www.intechopen.com/chapters/57159 

3. Kim Y, Ko H, Kwon IK, Shin K. Extracellular matrix revisited: roles in tissue engineering. International neurourology journal. 2016 May 26;20(Suppl 1):S23. https://pmc.ncbi.nlm.nih.gov/articles/PMC4895908/pdf/inj-1632600-318.pdf 

4. He M, Callanan A, Lagaras K, Steele JA, Stevens MM. Optimization of SDS exposure on preservation of ECM characteristics in whole organ decellularization of rat kidneys. Journal of biomedical materials research part b: applied biomaterials. 2017 Aug;105(6):1352-60. https://www.research.ed.ac.uk/files/25008282/Optimisation_of_SDS_exposure.pdf 

5. Keane TJ, Swinehart IT, Badylak SF. Methods of tissue decellularization used for preparation of biologic scaffolds and in vivo relevance. Methods. 2015 Aug 1;84:25-34. https://www.sciencedirect.com/science/article/am/pii/S1046202315000997 

6. Jiang K, Chaimov D, Patel SN, Liang JP, Wiggins SC, Samojlik MM, Rubiano A, Simmons CS, Stabler CL. 3-D physiomimetic extracellular matrix hydrogels provide a supportive microenvironment for rodent and human islet culture. Biomaterials. 2019 Apr 1;198:37-48. https://pmc.ncbi.nlm.nih.gov/articles/PMC6397100/pdf/nihms-1506842.pdf 

7. Guruswamy Damodaran R, Vermette P. Decellularized pancreas as a native extracellular matrix scaffold for pancreatic islet seeding and culture. Journal of tissue engineering and regenerative medicine. 2018 May;12(5):1230-7. https://doi.org/10.1002/term.2655 

8. Smink AM, de Vos P. Therapeutic strategies for modulating the extracellular matrix to improve pancreatic islet function and survival after transplantation. Current diabetes reports. 2018 Jul;18(7):39. https://link.springer.com/content/pdf/10.1007/s11892-018-1014-4.pdf