Noninvasive Monitoring of In Situ Oxygenation and Cell Therapy in Infarct Heart

描述(申请人提供)：心脏病是美国的主要死因。心脏移植是治疗终末期心力衰竭的唯一有效的临床治疗方法，但它只适用于少数患者。在心脏梗死区移植未成熟细胞，如干细胞或成肌细胞，被称为细胞疗法，似乎是一种有前途的替代策略。来自腿部骨骼肌组织的成肌细胞可以增殖和分化为功能细胞，从而改善心脏功能。然而，移植的成肌细胞的存活/增殖概率往往不到1%。严重缺氧(低氧水平)被认为是导致细胞治疗结果不佳的一个因素。因此，迫切需要准确评估作为心脏组织再生功能的移植成肌细胞中的氧浓度，特别是细胞内的氧合作用。因此，本研究的目标是开发创新的探针和方法，用于无创性监测心肌再生过程中细胞氧合的变化。我们开发了一类新的自旋探针，可以通过电子顺磁共振(EPR)光谱/成像直接检测，检测灵敏度显著提高。该探针由锂化萘菁大环配体的中性基团堆叠而成。此外，该探头可以报告组织氧浓度的绝对值，具有显著的氧敏感性(优于0.1Torr)。它们能够在封闭的胸腔中精确、准确和重复地测量几个月内的心肌氧合。这些探针可以有效地内化到细胞内，以研究细胞的增殖和迁移。这项建议的目的是利用这些新的探针来无创性地监测心肌梗死区域移植细胞的存活和增殖。该建议特别致力于研究：1.在成肌细胞中建立最优的内化程序和自旋探针的特征，用于细胞跟踪和细胞内氧浓度的测定；2.对梗死心脏中移植的干细胞植入、迁移和植入部位的原位氧合进行无创性监测；3.评估成肌干细胞在低氧培养或间歇性缺氧/复氧条件下对其在梗死心脏中移植后存活、保持、整合和原位氧合的效果。这些创新的探针和技术的可获得性将增强我们监测细胞治疗的能力，并应为人类心脏病的治疗开辟新的途径。

DESCRIPTION (provided by applicant): Heart disease is the leading cause of death in the United States. Heart transplantation is the only clinically effective therapy for end-stage heart failure, but it is available to only a few patients. Transplantation of immature cells, such as stem cells or myoblasts, in the infarct area of the heart, known as cell therapy, appears to be a promising alternative strategy. The myoblasts, derived from leg skeletal muscle tissue, can proliferate and differentiate into functional cells and thereby improve heart function. However, the probability of survival/proliferation of the transplanted myoblasts is often less than 1%. Severe hypoxia (low oxygen levels) is hypothesized as a factor responsible for the poor outcome of cell therapy. Thus, there is a pressing need to precisely evaluate the oxygen concentration, particularly intracellular oxygenation, in the transplanted myoblasts as a function of cardiac tissue regeneration. Therefore, the goal of the present study is to develop innovative probes and methods for noninvasive monitoring of the changes in the cellular oxygenation during myocardial regeneration. We have developed a new class of spin probes that can be directly detected by electron paramagnetic resonance (EPR) spectroscopy/imaging with markedly higher sensitivity for detection. The probes are composed of stacks of neutral radicals of lithiated naphthalocyanine macrocyclic ligands. In addition, the probes can report absolute values of tissue oxygen concentration with remarkable oxygen sensitivity (better than 0.1 Torr). They enable precise, accurate and repeated measurements of myocardial oxygenation over a period of several months in closed chests. The probes can be efficiently internalized into cells to study cell proliferation and migration. The objective of this proposal is to utilize these novel probes for noninvasive monitoring of the survival and proliferation of the transplanted cells in the infarct area of the myocardium. The proposal specifically seeks to study: 1. Establishment of optimal internalization procedures and characterization of the spin probe in myoblasts for cell-tracking and determination of intracellular oxygen concentration; 2. Noninvasive monitoring of in situ oxygenation at the site of implant, migration, and engraftment of transplanted stem cells in infarcted hearts; 3. Evaluation of the efficacy of myoblast stem cells subjected to hypoxic culture or intermittent hypoxia/reoxygenation on the survival, retention, integration, and in situ oxygenation after their transplantation in the infarcted heart. The availability of these innovative probes and technologies will enhance our ability to monitor cell therapy and should open new avenues in the treatment of heart disease in humans.