CLOSURE OF THE PRIMATE DUCTUS ARTEROISUS

灵长类动物动脉导管闭合

• 批准号: 7716091
• 负责人: RONALD I CLYMAN
• 金额: $ 2.26万
• 依托单位: TEXAS BIOMEDICAL RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-05-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7716091
• 关键词: Affect; Anatomy; Appearance; Area; Behavior; Bioluminescence; Birth; Blood flow; Cell Death; Cells; Closure; Computer Retrieval of Information on Scientific Projects Database; Condition; Constriction procedure; Contracts; Diffusion; Drops; Ductus Arteriosus; Enzymes; Fetus; Freezing; Funding; Glucose; Glycogen; Glycolysis; Grant; HIF1A gene; Hour; Hypoxia; Image; In Situ Nick-End Labeling; In Vitro; Incidence; Incubated; Institution; Legal patent; Link; Muscle; Newborn Infant; Numbers; Nutrient; Oxygen; Papio; Primates; Research; Research Personnel; Resistance; Resources; Sheep; Source; Staining method; Stains; Surrogate Markers; Tissues; United States National Institutes of Health; Vascular Endothelial Growth Factors; day; falls; fetal; in vivo; mRNA Expression; postnatal

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In contrast with the full term ductus, constriction of the immature ductus frequently fails to cause luminal obliteration and only moderately increases diffusion distances for oxygen and nutrients within its muscle media. This is associated with less cell death and less remodeling and leads to persistent ductus luminal blood flow after birth. In addition to the absence of anatomic remodeling, the immature newborn ductus progressively loses its ability to constrict during the first days after birth. The explanation for the impaired contractility of the persistently patent immature newborn ductus is currently unknown. During the past year we examined ductus from full term and immature fetal and newborn baboons to determine how constriction of the ductus arteriosus affects the concentrations of oxygen, glucose, glycogen, and ATP in the ductus wall in vivo; and, to determine how these changes relate to the appearance of cell death in the vessel's wall and to the ability of the ductus to constrict after birth. We determined cell death (using TUNEL staining), energy status (using enzyme-linked bioluminescence imaging) and tissue hypoxia (using HIF1 alpha and VEGF mRNA expression as a surrogate marker) in frozen ductus obtained from baboons: 185d fetus (n= 11), 1-2 d old full term newborn (n=10), 125 d fetus (n=14), 125 d (6 d PRN) newborn (with open ductus, n=16), 125 d (6 d PRN) newborn (with closed ductus, n=10). In the full term baboon ductus, the expression of our two surrogate markers of hypoxia (HIF1alpha and VEGF) increased and the average concentrations of ATP, glucose and glycogen decreased following postnatal ductus constriction. The concentrations of ATP, glucose, and glycogen were significantly related to the degree of ductus constriction. In the full term baboon ductus there was also a significant relationship between the degree of ductus constriction and the logarithmic transformation of the number of TUNEL-positive cells (our indicator of cell death) (area of ductus lumen versus TUNEL log10: r=-0.92, p15% TUNEL-positive cells) only occurred when the ductus was closed and there was no Doppler flow through its lumen. In the premature ductus, ATP concentrations were directly related to tissue glucose concentrations but not to glycogen concentrations. Similarly, cell death (TUNEL staining) was related to tissue glucose concentrations but not to glycogen concentrations in the immature ductus. This is consistent with our previous in vitro studies that showed that the primary substrate utilized during glycolysis is glucose, not glycogen. In addition, during tight constriction and tissue hypoxia, the immature ductus actually develops regions where glycogen concentrations were actually greater than those observed in the fetus. We have previously shown that ductus rings, incubated in vitro under hypoxic conditions, develop both regions of glycogen depletion as well as regions of glycogen surplus: interestingly, the regions of glycogen surplus are more commonly seen in the immature than the mature ductus. We hypothesize that this adaptive mechanism could add to the ability ,of the immature ductus to tolerate episodes of hypoxia and nutrient shortage making it more resistant to developing postnatal cell death and permanent closure. Although the changes in HIF1alphaNEGF expression and ATP concentrations were significantly related to the degree of ductus constriction in the premature ductus, we were surprised to find that both HIF1alphaNEGF expression and ATP concentrations were still significantly altered after birth even when the immature ductus remained open and continued to have persistent luminal blood flow. We used ductus arteriosus from preterm lamb fetuses to determine if the drop in ductus ATP concentrations, that occur after birth in preterm newborns with an open ductus, is sufficient to alter ductus contractility. We examined the contractile behavior of immature sheep ductus in vitro exposed to 80% 02 and two different concentrations of glucose. At low glucose concentrations, ATP concentrations were not maintained and fell to 31 % of the starting (0 hr) fetal ductus levels. This is similar to the in vivo drop in ATP concentration observed in the immature newborn baboon ductus that remains open after birth. In contrast, in the rings exposed to normal glucose concentrations, ATP concentrations were stable during the 24 hr incubation, There was no difference between the mo experimental groups in the incidence of cell death (TUNEL staining) or remodeling during the in vitro incubation (24 hours). Ductus with normal concentrations of glucose and ATP contracted when exposed to 80% oxygen for 24 hours; in contrast, ductus with low glucose and low ATP failed to contract when exposed to 80% oxygen.

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 与完整的导管相比，未成熟导管的狭窄通常不会导致管腔闭塞，只是适度地增加了氧气和营养物质在肌肉中的扩散距离。这与较少的细胞死亡和较少的重塑有关，并导致出生后持续的管腔血流。除了没有解剖重建，未成熟的新生导管在出生后的头几天逐渐失去收缩的能力。持续未成熟的新生儿导管持续未闭的收缩功能受损的原因目前尚不清楚。 在过去的一年里，我们研究了足月和未成熟的胎儿和新生儿的动脉导管，以确定动脉导管的收缩如何影响体内导管壁上的氧、葡萄糖、糖原和三磷酸腺苷的浓度；并确定这些变化如何与管壁细胞死亡的出现和出生后导管收缩的能力有关。本研究采用原位末端标记法(TUNEL法)、酶联生物发光显像法(EL I)和组织缺氧法(以HIF1α和血管内皮生长因子(VEGF)m RNA表达作为替代标记物)，分别检测了185d胎儿(n=11)、1~2d足月新生儿(n=10)、125d胎儿(n=14)、125d(6d PRN)新生儿(n=16)、125d(6d PRN)新生儿(n=10)冰冻导管的细胞死亡、能量状态和组织缺氧情况。 在足月的狒狒导管中，我们的两个缺氧替代标志物(HIF1α和VEGF)的表达随着出生后导管狭窄而增加，而ATP、葡萄糖和糖原的平均浓度则下降。三磷酸腺苷、葡萄糖和糖原的浓度与导管狭窄程度显著相关。此外，在猴足月时，导管狭窄的程度与TUNEL阳性细胞数(细胞死亡的指标)对数转换(管腔面积与TUNEL的对数10：r=-0.92，p15%TUNEL阳性细胞)仅发生在导管关闭且无多普勒血流流过其管腔时。 在早产儿导管中，ATP浓度与组织葡萄糖浓度直接相关，但与糖原浓度无关。同样，细胞死亡(TUNEL染色)与组织中的葡萄糖浓度有关，但与未成熟导管中的糖原浓度无关。这与我们之前的体外研究一致，该研究表明糖酵解过程中利用的主要底物是葡萄糖，而不是糖原。此外，在紧密收缩和组织缺氧期间，未成熟的导管实际上会形成糖原浓度高于胎儿体内的糖原浓度的区域。我们之前已经证明，在体外低氧条件下孵育的导管环，既会出现糖原耗竭区域，也会出现糖原盈余区域：有趣的是，糖原盈余区域在未成熟的导管中比在成熟的导管中更常见。我们推测，这种适应机制可以增加未成熟导管耐受缺氧和营养缺乏的能力，使其更能抵抗出生后细胞死亡和永久关闭。 虽然HIF1αNEGF的表达和ATP浓度的变化与早产儿导管狭窄的程度显著相关，但我们惊讶地发现，即使在未成熟的导管仍然开放并持续存在管腔血流的情况下，HIF1αNEGF的表达和ATP浓度在出生后仍有显著变化。我们使用早产羔羊胎儿的动脉导管来确定导管开放的早产儿出生后动脉导管三磷酸腺苷浓度的下降是否足以改变导管的收缩能力。我们研究了80%O2和两种不同浓度的葡萄糖对体外培养的未成熟绵羊导管收缩行为的影响。在低糖浓度下，三磷酸腺苷浓度没有维持，下降到开始(0小时)胎儿导管水平的31%。这类似于在出生后仍然开放的未成熟的新生狒狒导管中观察到的体内ATP浓度的下降。与之相反，暴露于正常葡萄糖浓度的环中，ATP浓度在24小时孵育期间是稳定的，在体外孵育期间(24小时)细胞死亡(TUNEL染色)或重塑的发生率在mo实验组之间没有差异。葡萄糖和ATP浓度正常的导管在暴露于80%氧气24小时时收缩；相反，低血糖和低ATP的导管在暴露于80%氧气时不收缩。