Encapsulated Allografts Preclude Host Sensitization and Promote Ovarian Endocrine Function in Ovariectomized Young Rhesus Monkeys and Sensitized Mice.

Transplantation of allogeneic donor ovarian tissue holds great potential for female cancer survivors who often experience premature ovarian insufficiency. To avoid complications associated with immune suppression and to protect transplanted ovarian allografts from immune-mediated injury, we have developed an immunoisolating hydrogel-based capsule that supports the function of ovarian allografts without triggering an immune response. Encapsulated ovarian allografts implanted in naïve ovariectomized BALB/c mice responded to the circulating gonadotropins and maintained function for 4 months, as evident by regular estrous cycles and the presence of antral follicles in the retrieved grafts. In contrast to non-encapsulated controls, repeated implantations of encapsulated mouse ovarian allografts did not sensitize naïve BALB/c mice, which was confirmed with undetectable levels of alloantibodies. Further, encapsulated allografts implanted in hosts previously sensitized by the implantation of non-encapsulated allografts restored estrous cycles similarly to our results in naïve recipients. Next, we tested the translational potential and efficiency of the immune-isolating capsule in a rhesus monkey model by implanting encapsulated ovarian auto- and allografts in young ovariectomized animals. The encapsulated ovarian grafts survived and restored basal levels of urinary estrone conjugate and pregnanediol 3-glucuronide during the 4- and 5-month observation periods. We demonstrate, for the first time, that encapsulated ovarian allografts functioned for months in young rhesus monkeys and sensitized mice, while the immunoisolating capsule prevented sensitization and protected the allograft from rejection.

Opportunities for shared decision-making about major surgery with high-risk patients: a multi-method qualitative study.

BACKGROUND: Little is known about the opportunities for shared decision-making when older high-risk patients are offered major surgery. This study examines how, when, and why clinicians and patients can share decision-making about major surgery. METHODS: This was a multi-method qualitative study, combining video recordings of preoperative consultations, interviews, and focus groups (33 patients, 19 relatives, 36 clinicians), with observations and documentary analysis in clinics in five hospitals in the UK undertaking major orthopaedic, colorectal, and/or cardiac surgery. RESULTS: Three opportunities for shared decision-making about major surgery were identified. Resolution-focused consultations (cardiac/colorectal) resulted in a single agreed preferred option related to a potentially life-threatening problem, with limited opportunities for shared decision-making. Evaluative and deliberative consultations offered more opportunity. The former focused on assessing the likelihood of benefits of surgery for a presenting problem that was not a threat to life for the patient (e.g., orthopaedic consultations) and the latter (largely colorectal) involved discussion of a range of options while also considering significant comorbidities and patient preferences. The extent to which opportunities for shared decision-making were available, and taken up by surgeons, was influenced by the nature of the presenting problem, clinical pathway, and patient trajectory. CONCLUSIONS: Decisions about major surgery were not always shared between patients and doctors. The nature of the presenting problem, comorbidities, clinical pathways, and patient trajectories all informed the type of consultation and opportunities for sharing decision-making. Our findings have implications for clinicians, with shared decision-making about major surgery most feasible when the focus is on life-enhancing treatment.

Human Ovarian Follicles Xenografted in Immunoisolating Capsules Survive Long Term Implantation in Mice.

Female pediatric cancer survivors often develop Premature Ovarian Insufficiency (POI) owing to gonadotoxic effects of anticancer treatments. Here we investigate the use of a cell-based therapy consisting of human ovarian cortex encapsulated in a poly-ethylene glycol (PEG)-based hydrogel that replicates the physiological cyclic and pulsatile hormonal patterns of healthy reproductive-aged women. Human ovarian tissue from four donors was analyzed for follicle density, with averages ranging between 360 and 4414 follicles/mm3. Follicles in the encapsulated and implanted cryopreserved human ovarian tissues survived up to three months, with average follicle densities ranging between 2 and 89 follicles/mm3 at retrieval. We conclude that encapsulation of human ovarian cortex in PEG-based hydrogels did not decrease follicle survival after implantation in mice and was similar to non-encapsulated grafts. Furthermore, this approach offers the means to replace the endocrine function of the ovary tissue in patients with POI.

Immuno-Isolating Dual Poly(ethylene glycol) Capsule Prevents Cancer Cells from Spreading Following Mouse Ovarian Tissue Auto-Transplantation.

For female cancer survivors, premature ovarian insufficiency (POI) is a common complication of anticancer treatments. Ovarian tissue cryopreservation before treatment, followed by auto-transplantation after remission is a promising option to restore fertility and ovarian endocrine function. However, auto-transplantation is associated with the risk of re-introducing malignant cells harbored in the stroma of the ovarian autograft. To mitigate this risk, we investigated in this pilot study whether an immuno-isolating dual-layered poly(ethylene glycol)(PEG) capsule can retain cancer cells, while supporting folliculogenesis. The dual PEG capsule loaded with 1000 4T1 cancer cells retained 100% of the encapsulated cells in vitro for 21 days of culture. However, a greater cell load of 10,000 cells/capsule led to capsule failure and cells' release. To assess the ability of the capsule to retain cancer cells, prevent metastasis, and support folliculogenesis in vivo we co-encapsulated cancer cells with ovarian tissue in the dual PEG capsule and implanted subcutaneously in mice. Control mice implanted with 2000 non-encapsulated cancer cells had tumors formed within 14 days and metastasis to the lungs. In contrast, no tumor mass formation or metastasis to the lungs was observed in mice with the same number of cancer cells encapsulated in the capsule. Our findings suggest that the immuno-isolating capsule may prevent the escape of the malignant cells potentially harbored in ovarian allografts and, in the future, improve the safety of ovarian tissue auto-transplantation in female cancer survivors.

Immunoisolating poly(ethylene glycol) based capsules support ovarian tissue survival to restore endocrine function.

A common irreversible adverse effect of life-saving anticancer treatments is loss of gonadal endocrine function and fertility, calling for a need to focus on post-treatment quality of life. Here, we investigated the use of poly(ethylene glycol)-vinyl sulfone (PEG-VS) based capsules to support syngeneic donor ovarian tissue for restoration of endocrine function in mice. We designed a dual immunoisolating capsule (PEG-Dual) by tuning the physical properties of the PEG hydrogels and combining proteolytically degradable and nondegradable layers to meet the numerous requirements for encapsulation and immunoisolation of ovarian tissue, such as nutrient diffusion and tissue expansion. Tuning the components of the PEG-Dual capsule to have similar physical properties allowed for concentric encapsulation. Upon implantation, the PEG-based capsules supported ovarian tissue survival and led to a significant decrease in follicle stimulating hormone levels 60 days postimplantation. Mice that received the implants resumed regular estrous cycle activity and follicle development in the implanted grafts. The PEG-Dual capsule provided an environment conducive for tissue survival, while providing a barrier to the host environment. This study demonstrated for the first time that immunoisolating PEG-VS capsules can support ovarian follicular development resulting in the restoration of ovarian endocrine function and can be applied to future allogeneic studies. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1381-1389, 2018.

The impact of functional groups of poly(ethylene glycol) macromers on the physical properties of photo-polymerized hydrogels and the local inflammatory response in the host.

Poly(ethylene glycol) (PEG) can be functionalized and modified with various moieties allowing for a multitude of cross-linking chemistries. Here, we investigate how vinyl sulfone, acrylate, and maleimide functional end groups affect hydrogel formation, physical properties, viability of encapsulated cells, post-polymerization modification, and inflammatory response of the host. We have shown that PEG-VS hydrogels, in the presence of a co-monomer, N-vinyl-2-pyrrolidone (NVP), form more efficiently than PEG-Ac and PEG-Mal hydrogels, resulting in superior physical properties after 6 min of ultraviolet light exposure. PEG-VS hydrogels exhibited hydrolytic stability and non-fouling characteristics, as well as the ability to be modified with biological motifs, such as RGD, after polymerization. Additionally, unmodified PEG-VS hydrogels resulted in lesser inflammatory response, cellular infiltration, and macrophage recruitment after implantation for 28 days in mice. These findings show that altering the end group chemistry of PEG macromer impacts characteristics of the photo-polymerized network. We have developed a tunable non-degradable PEG system that is conducive for cell or tissue encapsulation and evokes a minimal inflammatory response, which could be utilized for future immunoisolation applications. STATEMENT OF SIGNIFICANCE: The objective of this study was to develop a tunable non-degradable PEG system that is conducive for encapsulation and evokes a minimal inflammatory response, which could be utilized for immunoisolation applications. This study has demonstrated that reactive functional groups of the PEG macromers impact free radical mediated network formation. Here, we show PEG-VS hydrogels meet the design criteria for an immunoisolating device as PEG-VS hydrogels form efficiently via photo-polymerization, impacting bulk properties, was stable in physiological conditions, and elicited a minimal inflammatory response. Further, NVP can be added to the precursor solution to expedite the cross-linking process without impacting cellular response upon encapsulation. These findings present an additional approach/chemistry to encapsulate cells or tissue for immunoisolation applications.

Imaging the Stromal Vascular Fraction during Soft-Tissue Reconstruction.

BACKGROUND: Although fat grafting is an increasingly popular practice, suboptimal volume retention remains an obstacle. Graft enrichment with the stromal vascular fraction has gained attention as a method of increasing graft retention. However, few studies have assessed the fate and impact of transplanted stromal vascular fraction on fat grafts. In vivo imaging techniques can be used to help determine the influence stromal vascular fraction has on transplanted fat. METHODS: Stromal vascular fraction was labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethylindotricarbocyanine iodide (DiR), a near-infrared dye, and tracked in vivo. Proliferation and differentiation of labeled cells were assessed to confirm that labeling did not adversely affect cellular function. Different doses of labeled stromal vascular fraction were tracked within fat grafts over time using the in vivo imaging system. RESULTS: No significant differences in differentiation and proliferation were observed in labeled versus unlabeled cells (p > 0.05). A pilot study confirmed that stromal vascular fraction fluorescence was localized to fat grafts and different cell doses could be distinguished. A larger-scale in vivo study revealed that stromal vascular fraction fluorescence was statistically significant (p < 0.05) between different cell dose groups and this significance was maintained in higher doses (3 × 10(6) and 2 × 10(6) cells/ml of fat graft) for up to 41 days in vivo. CONCLUSIONS: DiR labeling allowed the authors to differentiate between cell doses and confirm localization. This article supports the use of DiR labeling in conjunction with in vivo imaging as a tool for imaging stromal vascular fraction within fat grafts.