Four-Dimensional Microvascular Analysis Reveals That Regenerative Angiogenesis in Ischemic Muscle Produces a Flawed Microcirculation
Four-Dimensional Microvascular Analysis Reveals That Regenerative Angiogenesis in Ischemic Muscle Produces a Flawed Microcirculation
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DOI：
10.1161/circresaha.116.310535
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发表时间：
2017-04-28
影响因子：
20.1
通讯作者：
Pickering, J. Geoffrey
中科院分区：
文献类型：
--
作者：
Arpino, John-Michael;Nong, Zengxuan;Pickering, J. Geoffrey
原理：骨骼肌缺血性损伤后发生血管生成，增强这种反应一直是治疗目标。然而，为了适当地输送氧气，必须形成精确组织和灵敏反应的微循环。这些网络属性是否存在于再生的微循环是未知的，和回答这个问题的方法一直lacked.Objective：开发4维的方法来阐明微结构和功能的重建微循环在骨骼肌muscle.Methods和Results：我们建立了一个完整的微循环再生模型缺血诱导闭塞后，在小鼠趾长伸肌。红细胞的动态成像显示了一个广泛的流动的新微血管网络的再生，14天后，在结构上类似于未受伤的肌肉。然而，骨骼肌仍然缺氧。红细胞转运分析显示，在再生毛细血管和广泛的小动脉-小静脉分流缓慢和停滞的流动。此外，毛细血管红细胞转运的空间异质性受到高度限制，红细胞氧饱和度较低且变化不适当。这些异常持续到受伤后120天。为了确定再生的微循环是否可以调节流量，使用透氧膜对肌肉进行局部缺氧。缺氧迅速增加红细胞的速度和流量在控制毛细血管，但在新生血管，反应迟钝。三维共聚焦成像显示，neoarterioles aberrantly覆盖的平滑肌细胞，与增加的interprocess间距和随意肌动蛋白微丝bundles.Conclusions：尽管强大的新生血管，骨骼肌再生血管形成的微循环是深刻的缺陷，在结构和功能，随着时间的推移，没有证据正常化。这种网络水平的功能障碍必须得到承认和克服，以推进缺血性疾病的再生方法。
Rationale: Angiogenesis occurs after ischemic injury to skeletal muscle, and enhancing this response has been a therapeutic goal. However, to appropriately deliver oxygen, a precisely organized and exquisitely responsive microcirculation must form. Whether these network attributes exist in a regenerated microcirculation is unknown, and methodologies for answering this have been lacking.Objective: To develop 4-dimensional methodologies for elucidating microarchitecture and function of the reconstructed microcirculation in skeletal muscle.Methods and Results: We established a model of complete microcirculatory regeneration after ischemia-induced obliteration in the mouse extensor digitorum longus muscle. Dynamic imaging of red blood cells revealed the regeneration of an extensive network of flowing neo-microvessels, which after 14 days structurally resembled that of uninjured muscle. However, the skeletal muscle remained hypoxic. Red blood cell transit analysis revealed slow and stalled flow in the regenerated capillaries and extensive arteriolar-venular shunting. Furthermore, spatial heterogeneity in capillary red cell transit was highly constrained, and red blood cell oxygen saturation was low and inappropriately variable. These abnormalities persisted to 120 days after injury. To determine whether the regenerated microcirculation could regulate flow, the muscle was subjected to local hypoxia using an oxygen-permeable membrane. Hypoxia promptly increased red cell velocity and flux in control capillaries, but in neocapillaries, the response was blunted. Three-dimensional confocal imaging revealed that neoarterioles were aberrantly covered by smooth muscle cells, with increased interprocess spacing and haphazard actin microfilament bundles.Conclusions: Despite robust neovascularization, the microcirculation formed by regenerative angiogenesis in skeletal muscle is profoundly flawed in both structure and function, with no evidence for normalizing over time. This network-level dysfunction must be recognized and overcome to advance regenerative approaches for ischemic disease.