Outcome of adrenal tissue fragments allotransplantation: the impact of cryopreservation

Neural differentiation potential of sympathoadrenal progenitors derived from fresh and cryopreserved neonatal porcine adrenal glands

Stem/progenitor cells are thought to have the potential in the treatment of severe neurodegenerative diseases. Recently, sympathoadrenal progenitors expressing specific markers of neural crest derivatives and capable to differentiate into neurons were discovered in adult bovine and human adrenal glands, but there was no reported data on cryopreservation of sympathoadrenal progenitors. The aim of the present study was to examine the neural differentiation potential of sympathoadrenal progenitors derived from fresh and cryopreserved neonatal porcine adrenal glands. Considering impact of various initial state of frozen biomaterial on cell recovery, we carried out a comparative estimation of cryopreservation outcome both for adrenal tissue fragments and isolated primary cells. The estimation consisted of determining cell yield, viability, ability to adhere, proliferate and differentiate in vitro. Cells isolated from the fresh adrenal glands were cultured until confluence. A formation of sympathoadrenal progenitors-embedded spherical cell colonies, whose cells are differentiated then into βIII-tubulin-positive cells with neuron-like morphology, was observed on the monolayer. The colonies were well preserved after cryopreservation of cell culture with a cooling rate of 1 °C/min in the cryoprotectant media containing 5-15% of dimethylsulfoxide. Adrenal tissue fragments were cryopreserved in the presence of 10% dimethylsulfoxide at the cooling rates of 0.3; 1: 5; 40 and > 100 °C/min. Sympathoadrenal progenitors were recovered after cryopreservation with 0.3 °C/min cooling rate but not higher.

Urethral reconstruction using allogenic frozen-thawed bladder mucosa: an experimental study

OBJECTIVE

To determine the feasibility and effectivity of allogenic frozen-thawed bladder mucosa for urethroplasty.

METHODS

Bladder mucosa was harvested from 6 New Zealand rabbits. Changes in the bladder mucosa as seen by histological and electron microscope examination were compared between the frozen-thawed and fresh groups. Twelve urethral stricture models were established and randomly divided into two groups. In the test group, we performed urethroplasty with allogenic frozen-thawed bladder mucosa, and the same operation was done in the control group, but using fresh bladder mucosa. The result of retrograde urethrography and histological changes of the urethral sample were compared postoperatively.

RESULTS

No obvious changes on histological and electron microscope examination were observed in the frozen-thawed bladder mucosa. Inflammation reaction of the surgical site in the test group was milder than that of the controls 2 weeks after surgery. The urethral epithelial cells grew well 2 weeks after surgery, but lots of epithelia were necrotic in the control group. The urethra of all rabbits in the test group had good continuity and the urethral lumen was large in the test group 2 months after surgery. There was a layer of urethral epithelium in the test group 2 months after surgery, whereas scar tissue was found in the control group.

CONCLUSIONS

The freeze-thaw technique can maintain bladder mucosa structure and biological function. Frozen-thawed allogenic bladder mucosa may be a potential material for urethroplasty.