Effect of cryopreservation on lymph node fragment regeneration after autologous transplantation in the minipig model

Introduction: Lymphoedema is a worldwide pandemic causing swelling of tissues due to dysfunctional transport of lymph fluid. Present management concepts are based in conservative palliation of symptoms through manual lymphatic drainage, use of compression garments, manual lymph drainage, exercise, and skin care. Nevertheless, some curative options as autologous lymph node transplantation were shown to reduce lymphoedema in selected cases. Lately, some concern has arisen due to reports of donor site morbidity. A possible solution could be the development of artificial lymph node scaffolds as niches of lymphatic regeneration. Engineering these scaffolds has included cryopreservation of lymph node stroma. However, the effects of cryopreservation on the regeneration capacities of these organs were unknown. Materials and methods: Here, we used the minipig animal model to assess lymphatic regeneration processes after cryopreservation of autologous lymph nodes. Superficial inguinal lymph nodes were excised and conserved at -80°C for 1 month. Thereafter, lymph node fragments were transplanted in the subcutaneous tissue. Results: Regeneration of the lymph nodes was assessed five months after transplantation. We show that lymph node fragment regeneration takes place in spite of former cryopreservation. Transplanted fragments presented typical histological appearance. Their draining capacity was documented by macroscopic transport of Berlin Blue dye as well as through SPECT-CT hybrid imaging. Discussion: In conclusion, our results suggest that processes of cryopreservation can be used in the creation of artificial lymph node scaffolds without major impairment of lymph node fragments regeneration.