| 1. |
- Söfteland, John M., 1977, et al.
(författare)
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Luminal polyethylene-glycol solution delays the onset of preservation injury in the human intestine.
- 2021
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Ingår i: American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons. - : Elsevier BV. - 1600-6143. ; 21:6, s. 2220-2230
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Tidskriftsartikel (refereegranskat)abstract
- The organ damage incurred during the cold storage (CS) of intestinal grafts has short and long-term consequences. Animal studies suggest that additional luminal preservation (LP) with polyethylene-glycol (PEG) may alleviate this damage. This study aims to validate these findings using human intestines. Ileal segments, perfused intravascularly with IGL-1 solution, were procured from 32 multiorgan donors and divided into two parts: one containing a PEG 3350-based solution introduced luminally (LP group) and another one without luminal treatment (control). Sampling was performed after 4h, 8h, 14h, and 24h of CS. Histology was assessed using the Chiu/Park score. Tight junctions (TJ), several inflammatory markers, and transcription factors were examined by immunofluorescence, ddPCR, and Western blot. Tissue water content (edema) was also measured. Apoptotic activity was assessed with caspase 2,3 and 9 assays. LP significantly lowered mucosal injury at all time points. Redistribution of TJ proteins occurred earlier and more severely in the control group. After 24h of CS, LP intestines showed an emerging unfolding protein response. Increased caspase-3 and -9 activity were found in the control group. The current results indicate that luminal PEG is safe and effective in reducing damage to the intestinal epithelium during CS.
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| 2. |
- Padma, Arvind M., et al.
(författare)
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Decellularization protocol-dependent damage-associated molecular patterns in rat uterus scaffolds differentially affect the immune response after transplantation.
- 2021
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Ingår i: Journal of tissue engineering and regenerative medicine. - : Hindawi Limited. - 1932-7005 .- 1932-6254. ; 15:7, s. 674-685
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Tidskriftsartikel (refereegranskat)abstract
- Scaffolds derived from decellularized tissue possess many advantages for bioengineering applications, including for novel infertility treatments. However, the decellularization process results in allogenic-independent damage-associated molecular patterns (DAMPs). This field is poorly studied, in particular for uterus bioengineering applications. An increased knowledge concerning the immune system activation after transplantation of decellularized tissue will enable safer construct development and thereby accelerate translation from research to clinic. We therefore transplanted rat uterus scaffolds produced by three different decellularization protocols based on Triton X-100 (P1 and P2) or sodium deoxycholate (P3) in a syngeneic animal model and assessed the immune response towards DAMPs exposed by the decellularization process. Biopsies were retrieved on day 5, 15, and 30 post transplantation and immunohistochemistry-stained CD45+ (leucocytes), CD4+ (T-cells), CD8a+ (cytotoxic T-cells), CD22+ (B-cells), NCR1+ (NK-cells), CD68+ (pan-macrophages), and CD163+ (M2 macrophages) cells within the grafts were quantified. The gene expression for interferon γ, interleukin (IL)-1β, IL-2, IL-6, and tumor necrosis factor (TNF) eotaxin-2, RANTES, MCP-1, MIP-1α, MIP-3α, IL-8 were also measured. Scaffolds from P1 induced a rapid cell infiltration after transplantation, presumably induced by DNA-based DAMPs. However, this response was only transient. Protocol 3 derived scaffolds induced an early pro-inflammatory cytokine response at the transcript level which remained high throughout the study. This response may be caused by the stronger decellularization detergent that could expose more extracellular matrix-related DAMPs. However, earlier proteomics analysis also identified significantly more abundant heat shook proteins-related DAMPs in this scaffold type. Protocol 2 caused the least immunogenic scaffolds and should thus be the future focus for in vivo uterus bioengineering applications.
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| 3. |
- Padma, Arvind M., et al.
(författare)
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Immune response after allogeneic transplantation of decellularized uterine scaffolds in the rat.
- 2021
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Ingår i: Biomedical Materials. - 1748-605X. ; 16:4
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Tidskriftsartikel (refereegranskat)abstract
- Data on how the immune system reacts to decellularized scaffolds after implantation is scarce and difficult to interpret due to many heterogeneous parameters such as tissue-type match, decellularization method and treatment application. The engraftment of these scaffolds must prove safe and that they remain inert to the recipient's immune system to enable successful translational approaches and potential future clinical evaluation. Herein, we investigated the immune response after the engraftment of three decellularized scaffold types that previously showed potential to repair a uterine injury in the rat. Protocol (P) 1 and P2 were based on Triton-X100 and generated scaffolds containing 820 ng mg-1and 33 ng mg-1donor DNA per scaffold weight, respectively. Scaffolds obtained with a sodium deoxycholate-based protocol (P3) contained 160 ng donor DNA per mg tissue. The total number of infiltrating cells, and the population of CD45+leukocytes, CD4+T-cells, CD8a+cytotoxic T-cells, CD22+B-cells, NCR1+NK-cells, CD68+and CD163+macrophages were quantified on days 5, 15 and 30 after a subcutaneous allogenic (Lewis to Sprague Dawley) transplantation. Gene expression for the pro-inflammatory cytokines INF-γ, IL-1β, IL-2, IL-6 and TNF were also examined. P1 scaffolds triggered an early immune response that may had been negative for tissue regeneration but it was stabilized after 30 d. Conversely, P3 initiated a delayed immune response that appeared negative for scaffold survival. P2 scaffolds were the least immunogenic and remained similar to autologous tissue implants. Hence, an effective decellularization protocol based on a mild detergent was advantageous from an immunological perspective and appears the most promising for futurein vivouterus bioengineering applications.
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| 4. |
- Padma, Arvind M.
(författare)
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Tissue engineering for novel female infertillity treatments: studies on small and large animal models
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: As with any transplantation (Tx) procedure, uterus Tx is associated with risky donor surgery and adverse side-effects from immunosuppression. With the aim to bypass these risks, this thesis investigated uterus tissue engineering strategies and the potential to develop a patient-specific uterus graft to replace the need for donor surgery and immunosuppression. A translational approach for uterus scaffold production through a process called decellularization (DC) is addressed using the rat and the sheep animal model. The immunological events following engraftment of rat uterus scaffolds was also evaluated. The thesis also assessed cellular reconstruction techniques and perfusion bioreactor protocols that can be useful to recellularize whole sheep uterus scaffolds for future uterus Tx studies. Methods: The immune response towards three different rat uterus scaffold types were evaluated after transplantation by quantifying infiltrating leucocytes and the expression of pro-inflammatory cytokines. Additionally, three novel whole sheep uterus scaffolds were produced by DC and the scaffold composition, bioactivity, mechanical strength and ability to support seeded stem cells were analyzed. Technique optimization for a perfusion bioreactor was also conducted using normal sheep uterus and a specialized perfusion medium. Results and conclusions: In Paper I, we deciphered DC protocol-dependent differences in the immune response following engraftment. A mild, yet effective DC protocol resulted in an immune-inert scaffold type. In Paper II-III, we developed three promising extracellular matrix-derived bioactive sheep uterus scaffolds that after an enzymatic pre-conditioning were able to support wide-spread cell attachment and migration during recellularization. In Paper IV, we were able to maintain normal sheep uterus ex-vivo for 48 hours using a custom made culture medium and a perfusion bioreactor. These parameters should facilitate future whole sheep uterus tissue engineering experiments so that a patient-specific tissue engineered uterus can be made to replace a donor in a uterus Tx setting.
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| 5. |
- Padma, Arvind M., et al.
(författare)
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Towards a bioengineered uterus: bioactive sheep uterus scaffolds are effectively recellularized by enzymatic preconditioning
- 2021
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Ingår i: Npj Regenerative Medicine. - : Springer Science and Business Media LLC. - 2057-3995. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Uterine factor infertility was considered incurable until recently when we reported the first successful live birth after uterus transplantation. However, risky donor surgery and immunosuppressive therapy are factors that may be avoided with bioengineering. For example, transplanted recellularized constructs derived from decellularized tissue restored fertility in rodent models and mandate translational studies. In this study, we decellularized whole sheep uterus with three different protocols using 0.5% sodium dodecyl sulfate, 2% sodium deoxycholate (SDC) or 2% SDC, and 1% Triton X-100. Scaffolds were then assessed for bioactivity using the dorsal root ganglion and chorioallantoic membrane assays, and we found that all the uterus scaffolds exhibited growth factor activity that promoted neurogenesis and angiogenesis. Extensive recellularization optimization was conducted using multipotent sheep fetal stem cells and we report results from the following three in vitro conditions; (a) standard cell culturing conditions, (b) constructs cultured in transwells, and (c) scaffolds preconditioned with matrix metalloproteinase 2 and 9. The recellularization efficiency was improved short-term when transwells were used compared with standard culturing conditions. However, the recellularization efficiency in scaffolds preconditioned with matrix metalloproteinases was 200-300% better than the other strategies evaluated herein, independent of decellularization protocol. Hence, a major recellularization hurdle has been overcome with the improved recellularization strategies and in vitro platforms described herein. These results are an important milestone and should facilitate the production of large bioengineered grafts suitable for future in vivo applications in the sheep, which is an essential step before considering these principles in a clinical setting.
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| 6. |
- Tsiartas, Panos, et al.
(författare)
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P–459 Ex vivo perfusion of whole ewe ovaries with follicular maturation for up to seven days: towards the development of an alternative fertility preservation method
- 2021
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Ingår i: Human Reproduction Vol 36 Issue Supplement 1. - : Oxford University Press (OUP). - 0268-1161.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Abstract Study question To develop an alternative fertility preservation method for young female cancer patients based on an ex vivo perfusion of whole ovaries serving as a platform for future ovarian stimulation studies. Summary answer It is possible to maintain viable follicles and to retrieve oocytes after ex vivo perfusion of ewe ovaries for up to 7 days. What is known already Some progress has been made in terms of follicular growth and the isolation of mature oocytes in vitro. However, full development, from early follicular stages to a viable offspring, has only been described in rodent models. The complex events controlling follicular expansion and the long time required for folliculogenesis and oocyte maturity in large mammalian species creating challenges and limitations for in vitro studies. Ex vivo perfusion of a whole ovary could potentially be a solution by exploiting the intact ovarian architecture to support folliculogenesis and oocyte maturation. Study design, size, duration Thirty-one ewe ovaries were divided into 4 groups and ex vivo perfused in a bioreactor. Group 1 (n=14) perfusion for 48hours with no hormone supplementation; Group 2 (n=4) perfusion 96–101hours with follicle stimulating hormone (FSH); Group 3 (n=3) perfusion 120–168hours with human menopausal gonadotropin (hMG); Group 4 (n=10) perfusion 72–144hours with hMG. Participants/materials, setting, methods Ewe ovaries from sexually mature ewes were ex vivo perfused in a bioreactor under normothermic conditions for up to 7 days (max total 168hours). Histomorphological, immunohistochemical, hormonal and biochemical analyses were performed to assess ovarian structure and viability after cold ischemia and after perfusion which was subsequently compared to control ovaries. Main results and the role of chance The perfused ovaries in group 2 and 3 showed no significant differences in follicular density, viability and oocyte quality after ischemia and perfusion compared to control ovaries. Estradiol and progesterone levels did not increase during the perfusion. The perfused ovaries in group 1 and 4 showed a significant decrease in the ovarian reserve and oocyte quality. In total, 16 GV-MI oocytes were retrieved from groups 3 and 4. Limitations, reasons for caution 1. Ovaries were retrieved from ewes of unknown cycle and reproductive history. 2. The perfusion medium was changed after 24hours from perfusion start to remove detrimental metabolites and this could affect the measured concentrations of hormones and metabolites in the perfusion medium. Wider implications of the findings: These results pave the way to propose ex vivo perfusion as a good platform for fertility preservation studies on whole mammalian and human ovaries to retrieve fully mature oocytes. Trial registration number Not applicable
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