NOVEL APPROACHES TO CRYOPRESERVATION OF HUMAN PANCREATIC ISLETS1
Bibliographic record
Abstract
BACKGROUND: Optimized conditions for survival and function of human islets must be defined if sufficient islets are to be recovered from a single human donor pancreas to reverse type-1 diabetes after isolation, cryopreservation, and transplantation. The objective of this study was to compare the cryoprotective effect of ethylene glycol (EG) with the standard cryoprotectant, dimethyl sulfoxide (DMSO), on isolated human islet survival and function. Furthermore, the effect of different addition protocols and equilibrium concentrations of the cryoprotectants were studied. METHODS: Islets were isolated from human pancreata by using standard techniques of collagenase digestion and discontinuous Ficoll gradient purification. Aliquots of freshly isolated human islets were cryopreserved in six groups by using DMSO or EG. Cryoprotectants were added stepwise to produce a final concentration of 1.5 or 2.0 M, or added in a single step to a concentration of 1.5 M. Islets were cryopreserved by using established protocols and cultured for 48 hr at 37 degrees C before assessment of percentage of recovery and in vitro viability. RESULTS: After cryopreservation, percentage of recovery of islets was significantly higher in the group treated with 1.5 M of DMSO added in a stepwise protocol (74+/-3%, mean+/-SEM) compared with the standard 2.0 M of DMSO (62+/-4%) (P<0.05, unpaired t test, n=6). There was no difference between the recovery of islets cryopreserved with either 1.5 M of DMSO stepwise (74+/-3%) or 1.5 M of DMSO one-step (69+/-3%). Islet recovery was higher in groups treated with DMSO compared with EG, regardless of concentration of cryoprotectant or addition protocol, although the difference was significant only when comparing DMSO and EG 1.5 M one-step. Furthermore, islets treated with 1.5 M of DMSO, added either stepwise (6.0+/-0.4) or in one-step (6.5+/-0.8), had significantly higher stimulation indices compared with islets treated with the standard cryoprotectant for human islets, 2.0 M of DMSO (4.5+/-0.5) (P<0.05). CONCLUSIONS: These results demonstrate that a lower concentration of DMSO (1.5 M) allows for the cryopreservation of human islets with superior survival and preservation of function post-culture compared with 2.0 M of DMSO and various concentrations of EG.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".