Development and Validation of Novel Coatings that Extend Glucose Sensor Accuracy and Lifespan in vivo

在任何成功的“人工胰腺”系统的发展中，最重要的因素是 高精度、长寿命的葡萄糖传感器，无需多次重新校准。通常，是可植入的 葡萄糖传感器在性能(准确性和响应时间)方面表现出不够的可靠性，这是 被认为是生物相容性差的结果。这些并发症的核心是这些传感器未能 成功地融入周围组织。事实上，现代葡萄糖传感器技术的主要范例之一 那就是“如果传感器不能与生物兼容，它就不会持久”。一般而言，传感器性能差被归因于 炎症、纤维化和血管退行性变(感应器诱导的组织反应(SITR))三位一体。这一失败就是 传感器引起的初始慢性炎症、组织破坏和强烈的疤痕形成，即传感器诱导的 组织反应。这类植入物引起的组织反应称为异物反应(FBR)。这些 FBRs是由活化的促炎巨噬细胞(M1MQ)驱动的。因此，抑制M1巨噬细胞的功能是 克服SITR/FBR及其相关并发症的关键。预防FBR的早期发病是 促进传感器成功地集成到组织中(即纤维血管组织的生长)，而不是强烈的 惊吓会导致广泛的并发症。以前克服SITR的努力通常集中在 使用合成聚合物涂层(+/-药物)，但成效有限。此外，各种传感器涂层，既有 人工合成和自然界中的生物，已经被使用，但收效甚微。在本申请中，我们建议 开发和验证新一代具有生物活性的外切体传感器涂层，该涂层将抑制 巨噬细胞功能，从而防止传感器诱导的FBR(炎症和纤维化)，在这样做的过程中，增强 传感器成功整合到周围组织中。为了达到这一目标，我们建议利用微囊(即 抗炎细胞(如调节性T细胞(Treg))。这些外显体将被整合到 基底膜基质，用作生物活性传感器涂层，将抑制传感器诱导 炎症、纤维化以及促进传感器植入部位的组织再生。如果这些生物活性 基于外体的涂层(即外基质)在抑制巨噬细胞激活和增强感受器方面是成功的 体内整合，在未来(第二阶段SBIR)，这些外切体将被分析为“货物”组成，例如，RNA， DNA和蛋白质。以往对外切体的研究表明，微囊/外切体中的microRNAs 是强大的“细胞重编程器”，合成的miRNAs正在被开发成尖端疗法。使用这个 信息，在未来，我们将利用基因工程的外显体从抗病毒中开发出“设计者外显体”。 炎症和促进伤口愈合的细胞，最终导致“合成外体”的发展，用于 外矩阵。我们预计miRNAs很可能是关键的外体货物成分，它将抑制 巨噬细胞在SITR/FBR中的作用，并将成为未来人工/合成外体的基础，这将 用于我们的外部矩阵传感器涂层。 好了！

An overarching factor in the development of any successful “artificial pancreas” system is the advancement of a highly accurate and long-lived glucose sensor, without the need for numerous recalibrations. Frequently, implantable glucose sensors demonstrate insufficient reliability with respect to performance (accuracy and response time), which is thought to be the result of poor biocompatibility. Central to these complications is the failure of these sensors to successfully integrate into surrounding tissue. In fact, one of the major paradigms of modern glucose sensor technology is that “if the sensor is not biocompatible, it will not last”. Generally, poor sensor performance has been attributed to the triad of inflammation, fibrosis, and vessel regression (sensor induced tissue reactions (SITR)). This failure is the result of initial chronic inflammation, tissue destruction, and intense scarring induced by the sensor, i.e. sensor induced tissue reactions. This class of implant-induced tissue reactions is referred to as foreign body reactions (FBR). These FBRs are driven by activated pro-inflammatory-macrophages (M1MQ). Thus, suppressing M1 macrophage function is key to overcoming SITR/FBR and the associated complications. Preventing the early onset of FBR is central to promoting successful integration of sensor into tissue (i.e. ingrowth of fibro-vascular tissue) rather than intense scaring resulting in a wide range of complications. Previous efforts to overcome SITR have generally focused on the usage of synthetic polymer coatings (+/- drugs), but with limited success. In addition, a variety of sensor coatings, both synthetic and biologic in nature, have been used, but with limited success. In the present application, we propose to develop and validate a new generation of biologically active exosome-based sensor coatings that will suppress macrophage function and thereby prevent sensor-induced FBR (inflammation and fibrosis), in so doing, enhancing successful sensor integration into surrounding tissue. To achieve this goal, we propose to utilize microvesicles (i.e. exosomes) from anti-inflammatory cells (e.g. regulatory T cells (Treg)). These exosomes will be incorporated into basement membrane matrices, and utilized as bioactive sensor coatings, which will suppress sensor-induced inflammation, fibrosis, as well as promote tissue regeneration at sensor implantation sites. If these bioactive exosome-based coatings (i.e. Exo-Matrices) are successful in suppressing macrophage activation and enhancing sensor integration in vivo, in the future (Phase 2 SBIR), these exosomes will be analyzed for “cargo” composition, e.g., RNA, DNA and protein. Previous studies of exosome cargo have demonstrated that the microRNAs in microvesicles/exosomes are powerful “cell re-programmers”, and synthetic miRNAs are being developed into cutting edge therapies. Using this information, in the future, we will develop “designer exosomes” using genetically engineered exosomes from anti- inflammatory & pro-wound healing cells, ultimately leading to the development of “synthetic exosomes” for uses in Exo-Matrices. We anticipate the miRNAs will likely be the key exosome cargo component that will suppress macrophage function during SITR/FBR, and will be the foundation for future artificial/synthetic exosomes, which will be used in our Exo-Matrices coatings of sensors. !