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Biomaterials induced host immune responses, and fibrotic overgrowth remains a major barrier to the long-term function of medical devices and biomaterial consisting of tissue grafts. Screening new biomaterials to identify anti-fibrotic formulation requires in vivo testing, which is challenging to multiplex and remains a significant obstacle to progress in this field. Herein, we synthesized a combinatorial chemically modified hydrogel library and developed a cellular barcoding method that enables high-throughput multiplexed in vivo screening of 20 formulations in a single mouse and 100 formulations in a single non-human primate. Our screening method consists of implanting a mixture of biomaterials and each barcoded with human umbilical vein epithelial cells (HUVEC) from different individual donors. Single nucleotide polymorphism (SNP) genotypes of the cells were utilized as readouts using next-generation sequencing (NGS) to pair the material identity with material performance. Screening of the library using a xenogeneic transplantation model identified three novel lead hydrogel formulations (Z4-A10, Z1-A3, and Z2-A19) with improved anti-fibrotic properties that enable long-term cell viability. Z4-A10 was used to encapsulate human islets and validated for long-term glycemic control in an STZ-induced C57BL/6J diabetic mouse model. Leads, Z1-A3 and B2-A17, were further validated as immunomodulating coatings for medical-grade catheters to prevent fibrosis and occlusion, highlighting the translation of our screening approach and findings to other medical devices. Our results suggest that the developed cellular barcoding method and in vivo multiplexed screening technique can be leveraged to identify biomaterials for a wide range of clinical applications. Significantly, our newly discovered leads can improve the long-term performance of medical devices and encapsulated cell-based therapeutics.

Code and data used in the theoretical model of intraperitoneal cytokine delivery used in the publication., Funding Sources: Cancer Prevention Research Institute of Texas grant RR160047 (OV) Avenge Bio Sponsored Research Agreement to Rice University (OV) and Cell Trans (JO) Emerson Collective (AJ, WP) Welch Foundation (OI, ADH) Rice University Academy Fellowship (MJ) National Science Foundation grant 1842494 (AN) National Institute of Health grant 1RO1DK120459-01 (AN, OV)

Pro-inflammatory cytokines have been approved as a cancer immunotherapy for treatment of metastatic melanoma and renal carcinoma for over 30 years. However, widespread use of cytokine therapy in the clinic is limited by its short half-life in circulation and the associated toxicities that emerge as a result of high systemic exposure. To overcome these limitations, we developed a clinically translatable cytokine delivery platform, called cytokine factories, composed of genetically engineered epithelial cells encapsulated in biocompatible polymers. These cells are able to produce a wide range of natural cytokines (IL2, IL7, IL10, or IL12) and allow for controlled and predictable dosing in vivo. In vivo administration of cytokine factories created a high local cytokine concentration (IP space) without substantial leakage into the systemic circulation. Local, or tumor adjacent, administration of pro-inflammatory (IL-2-based) cytokine factories caused reduction of tumor burden by 70% after only 1 week of treatment when delivered as a monotherapy to mice with malignant pleural mesothelioma (MPM). Importantly, when administered in combination with local anti-PD1 injections, these cytokine factories lead to eradication of these highly aggressive tumors in 7/7 treated mice. To validate the translatability of this platform, we evaluated the safety profile in non-human primates. Significantly, this platform produced local and systemic T cell biomarker profiles that predict efficacy without renal, liver, or general toxicity in non-human primates. Our findings demonstrate the safety and efficacy of cytokine factories in preclinical animal models and provide rationale for future clinical testing for the treatment of metastatic peritoneal cancers in humans. Citation Format: Amanda Nash, Samira Aghlara-Fotovat, Andrea Hernandez, Bertha Castillo, Alexander Lu, Aarthi Pugazenthi, Peter Rios, Sofia Ghani, Ira Joshi, Douglas Isa, Chunyu Xu, Rahul Sheth, Weiyi Peng, Jose Oberholzer, Amir Jazaeri, Hee-Jin Jang, Bryan Burt, Hyun-Sung Lee, Ravi Ghanta, Omid Veiseh. Evaluation of implantable cytokine factories in combination with checkpoint inhibitors for eradication of malignant pleural mesothelioma (MPM) tumors in mice with safe and predictable dosing in non-human primates [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4189.

A next-generation cure for type 1 diabetes relies on immunoprotection of insulin-producing cells, which can be achieved by their encapsulation in microspheres made of non-covalently crosslinked hydrogels. Treatment success is directly related to the microsphere structure that is characterized by the localization of the polymers constituting the hydrogel material. However, due to the lack of a suitable analytical method, it is presently unknown how the microsphere structure changes in vivo, which complicates evaluation of different encapsulation approaches. Here, confocal Raman microscopy (CRM) imaging was tailored to serve as a powerful new tool for tracking structural changes in two major encapsulation designs, alginate-based microbeads and multi-component microcapsules. CRM analyses before implantation and after explantation from a mouse model revealed complete loss of the original heterogeneous structure in the alginate microbeads, making the intentionally high initial heterogeneity a questionable design choice. On the other hand, the structural heterogeneity was conserved in the microcapsules, which indicates that this design will better retain its immunoprotective properties in vivo. In another application, CRM was used for quantitative mapping of the alginate concentration throughout the microbead volume. Such data provide invaluable information about the microenvironment cells would encounter upon their encapsulation in alginate microbeads.

Continuous glucose monitors (CGMs), used by patients with diabetes mellitus, can autonomously track fluctuations in blood glucose over time. However, the signal produced by CGMs during the initial recording period following sensor implantation contains substantial noise, requiring frequent recalibration via fingerprick tests. Here, we show that coating the sensor with a zwitterionic polymer, found via a combinatorial-chemistry approach, significantly reduces signal noise and improves CGM performance. We evaluated the polymer-coated sensors in mice as well as in healthy and diabetic non-human primates, and show that the sensors accurately record glucose levels without the need for recalibration. We also show that the polymer-coated sensors significantly abrogated immune responses to the sensor, as indicated by histology, fluorescent whole-body imaging of inflammation-associated protease activity, and gene expression of inflammation markers. The polymer coating may allow CGMs to become standalone measuring devices.

The transplantation of pancreatic islet cells could restore glycaemic control in patients with type-I diabetes. Microspheres for islet encapsulation have enabled long-term glycaemic control in diabetic rodent models; yet human patients transplanted with equivalent microsphere formulations have experienced only transient islet-graft function, owing to a vigorous foreign-body reaction (FBR), to pericapsular fibrotic overgrowth (PFO) and, in upright bipedal species, to the sedimentation of the microspheres within the peritoneal cavity. Here, we report the results of the testing, in non-human primate (NHP) models, of seven alginate formulations that were efficacious in rodents, including three that led to transient islet-graft function in clinical trials. Although one month post-implantation all formulations elicited significant FBR and PFO, three chemically modified, immune-modulating alginate formulations elicited reduced FBR. In conjunction with a minimally invasive transplantation technique into the bursa omentalis of NHPs, the most promising chemically modified alginate derivative (Z1-Y15) protected viable and glucose-responsive allogeneic islets for 4 months without the need for immunosuppression. Chemically modified alginate formulations may enable the long-term transplantation of islets for the correction of insulin deficiency.

The transplantation of pancreatic islet cells could restore glycaemic control in patients with type 1 diabetes. Microspheres for islet encapsulation have enabled long-term glycaemic control in rodent models of diabetes; however, humans transplanted with equivalent microsphere formulations have experienced only transient islet graft function owing to a vigorous foreign-body response (FBR), to pericapsular fibrotic overgrowth (PFO) and, in upright bipedal species, to the sedimentation of the microspheres within the peritoneal cavity. Here, we report the results of the testing in non-human primate (NHP) models of seven alginate formulations that were efficacious in rodents, including three that led to transient islet graft function in clinical trials. All formulations elicited significant FBR and PFO 1 month post implantation; however, three chemically modified, immune-modulating alginate formulations elicited a reduced FBR. In conjunction with a minimally invasive transplantation technique into the bursa omentalis of NHPs, the most promising chemically modified alginate derivative (Z1-Y15) protected viable and glucose-responsive allogeneic islets for 4 months without the need for immunosuppression. Chemically modified alginate formulations may enable the long-term transplantation of islets for the correction of insulin deficiency., National Institutes of Health (U.S.) (Grant EB000244), National Institutes of Health (U.S.) (Grant EB000351), National Institutes of Health (U.S.) (Grant DE013023), National Institutes of Health (U.S.) (Grant CA151884)

Type 1 diabetes mellitus (T1DM) is an autoimmune disease that results from the destruction of insulin-producing pancreatic β cells in the islets of Langerhans. Islet cell transplantation has become a successful therapy for specific patients with T1DM with hypoglycemic unawareness. The reversal of T1DM by islet transplantation is now performed at many major medical facilities throughout the world. However, many challenges must still be overcome in order to achieve continuous, long-term successful transplant outcomes. Two major obstacles to this therapy are a lack of islet cells for transplantation and the need for life-long immunosuppressive treatment. Microencapsulation is seen as a technology that can overcome both these limitations of islet cell transplantation. This review depicts the present state of microencapsulated islet transplantation. Microencapsulation can play a significant role in overcoming the need for immunosuppression and lack of donor islet cells. This review focuses on microencapsulation and the clinical status of the technology in combating T1DM.