约翰霍普金斯大学研究团队利用实验室培养的人类视网膜类器官取得突破性发现，揭示了维生素A衍生物（视黄酸）与甲状腺激素在胎儿发育过程中的协同作用机制 1。研究表明，这两种物质共同促使中央凹区域的蓝光敏感锥细胞转变为红光和绿光敏感锥细胞，这一过程为人类锐利视力的形成提供了新的解释 1。该研究成果发表于2026年的《美国国家科学院院刊》（PNAS），论文题为《A cell fate specification and transition mechanism for human foveolar cone subtype patterning》 1。
具体而言，在胎儿发育第10至12周时，仅占视网膜一小部分但参与约50%视觉感知的中央凹区域存在少量蓝色锥细胞 1。随着发育进入第14周，这些蓝色锥细胞似乎发生了身份转换，成为红色和绿色锥细胞 1。其背后的分子机制在于，视黄酸的分解限制了中心区域新蓝色锥细胞的形成，而甲状腺激素则鼓励剩余的蓝色锥细胞改变身份成为红/绿锥细胞 1。
这一发现直接挑战了维持约30年的“蓝色锥细胞迁移”传统理论，即旧观点认为蓝色锥细胞是通过物理方式离开该区域且细胞身份固定不变 1。相反，新证据支持细胞身份可转换的模型 1。该研究由通讯作者Robert J. Johnston Jr.和第一作者Katarzyna Hussey主导 1。尽管目前相关技术距离临床应用尚远，但这一发现为未来开发精准控制的感光细胞群体以治疗黄斑变性等视力损失疾病奠定了理论基础 1。
Scientists at Johns Hopkins University have identified a critical role for vitamin A derivatives in the development of sharp human vision, challenging a theory that has stood for nearly 30 years 1. The research reveals that retinoic acid, a derivative of vitamin A, works in concert with thyroid hormone to transform blue-light-sensitive cone cells into red- and green-light-sensitive ones within the fetal retina 1. This discovery overturns the long-held belief that blue cones simply migrate away from the central region without changing their identity, proposing instead that these cells actively switch their functional roles during a specific developmental window 1.
The study utilized lab-grown human retinal organoids to observe this transformation 1. During the 10th to 12th weeks of fetal development, a small number of blue cone cells were present in the foveola; by the 14th week, these cells had converted to red and green sensitivity 1. The mechanism involves the breakdown of retinoic acid limiting the formation of new blue cones in the center, while thyroid hormones encourage the remaining blue cones to change their identity 1. Although the foveola constitutes only a small fraction of the retina, it is responsible for approximately 50% of human visual perception 1. Published in Proceedings of the National Academy of Sciences (PNAS) in 2026, the work was led by first author Katarzyna Hussey and senior author Robert J. Johnston Jr. 1. The researchers noted that the findings could eventually inform cell therapies aimed at developing precisely controlled groups of photoreceptor cells to restore vision lost to conditions like macular degeneration, though such applications remain distant from clinical use 1.
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