The multiplicity of systems affected in Alzheimer’s disease (AD) brains calls for multi-target therapies. Although mesenchymal stem cells (MSC) are promising candidates, their clinical application is limited because of risks related to their direct implantation in the host. This could be overcome by exploiting their paracrine action. We herein demonstrate that in vivo systemic administration of secretome collected from MSC exposed in vitro to AD mouse brain homogenates (MSC-CS), fully replicates the cell-mediated neuroreparative effects in APP/PS1 AD mice. We found a complete but transient memory recovery by 7 days, which vanished by 14 days, after a single MSC-CS intravenous administration in 12-month or 22–24-month-old mice. Treatment significantly reduced plaque load, microglia activation, and expression of cytokines in astrocytes in younger, but not aged, mice at 7 days. To optimize efficacy, we established a sustained treatment protocol in aged mice through intranasal route. Once-weekly intranasal administration of MSC-CS induced persistent memory recovery, with dramatic reduction of plaques surrounded by a lower density of β-amyloid oligomers. Gliosis and the phagocytic marker CD68 were decreased. We found a higher neuronal density in cortex and hippocampus, associated with a reduction in hippocampal shrinkage and a longer lifespan indicating healthier conditions of MSC-CS-treated compared to vehicle-treated APP/PS1 mice. Our data prove that MSC-CS displays a great multi-level therapeutic potential, and lay the foundation for identifying the therapeutic secretome bioreactors leading to the development of an efficacious multi-reparative cocktail drug, towards abrogating the need for MSC implantation and risks related to their direct use.

阿尔茨海默病 (AD) 大脑中受影响的系统的多样性需要多靶点疗法。尽管间充质干细胞 (MSC) 是有前途的候选者，但由于与直接植入宿主相关的风险，它们的临床应用受到限制。这可以通过利用它们的旁分泌作用来克服。我们在此证明在体内从体外暴露于 AD 小鼠脑匀浆 (MSC-CS) 的 MSC 收集的分泌组的全身给药，完全复制了 APP/PS1 AD 小鼠中细胞介导的神经修复作用。我们发现在 12 个月或 22-24 个月大的小鼠中单次静脉注射 MSC-CS 后，7 天后记忆完全但短暂恢复，14 天后消失。在第 7 天时，治疗显着降低了年轻但未衰老的小鼠的斑块负荷、小胶质细胞活化和星形胶质细胞中细胞因子的表达。为了优化疗效，我们通过鼻内途径对老年小鼠建立了持续治疗方案。MSC-CS 每周一次鼻内给药诱导持续记忆恢复，显着减少被较低密度 β-淀粉样蛋白寡聚体包围的斑块。胶质增生和吞噬标志物 CD68 减少。我们发现皮质和海马中更高的神经元密度与海马收缩减少和更长的寿命相关，表明与载体治疗的 APP/PS1 小鼠相比，MSC-CS 治疗的条件更健康。我们的数据证明 MSC-CS 显示出巨大的多层次治疗潜力，并为确定治疗性分泌组生物反应器奠定基础，从而开发出一种有效的多修复鸡尾酒药物，从而消除对 MSC 植入的需求和相关风险他们的直接使用。