Overcoming Confounding to Characterize the Effects of Calcium Channel Blockers.
Overcoming Confounding to Characterize the Effects of Calcium Channel Blockers.
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DOI：
10.1093/function/zqad054
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发表时间：
2023
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高血压是全球主要死亡原因，每年导致 1040 万人死亡，其长期影响包括增加心肌梗塞、心力衰竭、中风、视网膜病变和肾脏疾病的风险。 1 目前高血压的治疗方法包括钙通道阻滞剂 (CCB)、血管紧张素转换酶抑制剂 (ACEIs)、血管紧张素受体阻滞剂 (ARB)、噻嗪类利尿剂和 β 阻滞剂。 1 其中，CCB 现在是最受欢迎的药物之一，也是目前的一线药物，在某些患者群体中具有较大的血压降低效果。 2 最流行的一种是二氢吡啶 CCB 氨氯地平，可以每天服用，效果好，副作用相对较少。最近，约翰逊等人。 3 对氨氯地平和 CCB 的总体安全性提出了质疑，因为他们报告说，所有 CCB 除了在抑制电压操纵的 Ca2+ 通道中发挥公认的作用外，还激活钙池操纵的 Ca2+ 内流 (SOCE)。此外，他们观察到 CCB 刺激大鼠主动脉平滑肌细胞的 SOCE 并促进更大的增殖，预计这会对血管功能产生负面影响。这些发现与之前的研究一致，之前的研究表明 SOCE 的阻断或基因缺失会损害血管平滑肌细胞增殖，可能会影响多种血管疾病。 4 事实上，STIM1 基因的遗传变异被确定为自发性高血压大鼠的修饰基因。 5 因此，了解 CCB 对 SOCE 的作用对许多血管疾病具有重要意义。与这个想法一致的是，Johnson 等人。还对约 20 000 份患者记录进行了流行病学分析，结果表明 CCB 会增加心力衰竭的风险。这一发现令人惊讶，因为它与支持当前临床指南的许多临床试验相悖，也与许多高血压和心力衰竭专家的临床经验背道而驰。然而，如果这些发现属实，则表明 CCB 不应成为高血压的一线药物，并且应重新审视其一般使用。 Bird 等人 6 试图严格测试氨氯地平和 CCB 对 SOCE 的影响并测试其临床效果。本研究与 Johnson 等人的主要区别之一。图3是用于测量胞质钙的Ca2+敏感荧光染料的选择。在Johnson等人的研究中，fura-2被用来测量Ca2+信号。然而，伯德等人。发现苯磺酸氨氯地平会干扰 fura 基染料信号的解释，因为氨氯地平和 fura-2 具有重叠的激发光谱。此外，他们发现氨氯地平在暴露几分钟后在细胞质内积聚，主导了fura-2负载细胞中的荧光信号，从而模拟了Ca2+瞬变。这与之前的研究一致，即氨氯地平可以穿过质膜并在细胞内囊泡中积累。 7 因此，Bird 等人。在二氢吡啶 CCB 的研究中，使用较长波长的染料 Cal-520 来监测胞质 Ca2+。与记者合作，他们没有发现这些药物直接激活 Ca2+ 释放激活的 Ca2+ (CRAC) 通道的证据。这项研究强调了使用不同技术或方法严格检验任何假设的重要性。然而，这些发现不仅仅是证明氨氯地平人为影响 Ca2+ 瞬变，这可能会混淆早期研究的解释。作者报告了氨氯地平对 Ca2+ 的复杂作用……
Hypertension is the leading cause of death globally, accounting for 10.4 million deaths annually, with long-term effects that include an increased risk of myocardial infarction, heart failure, stroke, retinopathy, and kidney disease. 1 Current therapies for hypertension include calcium channel blockers (CCBs), angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), thiazide diuretics, and beta blockers. 1 Of these, CCBs are now one of the most popular and are currently first-line agents, with numerically greater reductions in blood pressure in certain patient groups. 2 One of the most popular is the dihydropyridine CCB amlodipine, which can be taken daily, is effective, and has relatively few side effects. Recently, Johnson et al. 3 have raised questions regarding the safety of amlodipine and CCBs in general, as they reported that all CCBs activated store-operated Ca2+ entry (SOCE) in addition to their wellestablished role in the inhibition of voltage-operated Ca2+ channels. Moreover, they observed that CCBs stimulated SOCE in rat aortic smooth muscle cells and promoted greater proliferation, which would be expected to have negative impacts on vascular function. These findings are consistent with previous studies where blockade or genetic deletion of SOCE was shown to impair vascular smooth muscle cell proliferation, potentially impacting several vascular diseases. 4 In fact, genetic variation in the STIM1 gene was identified as a modifier gene for the spontaneously hypertensive rat. 5 Understanding the actions of CCB on SOCE therefore has implications on many vascular diseases. Consistent with this idea, Johnson et al. also performed an epidemiological analysis of∼ 20 000 patient records that suggested that CCBs increased the risk of heart failure. This finding was surprising as it was counter to the many clinical trials that underpin current clinical guidelines and runs counter to the clinical experience of many hypertension and heart failure specialists.However, if these findings were true, it would suggest that CCBs should not be first-line agents for hypertension and that their use in general should be revisited. This puts into the context of Bird et al., 6 who sought to rigorously test the effects of amlodipine and CCBs on SOCE as well as testing their clinical effects. One of the major differences from the present study and Johnson et al. 3 was the choice of Ca2+-sensitive fluorescent dyes that were used to measure cytosolic calcium. In the study by Johnson et al., fura-2 was used to measure Ca2+ signals. However, Bird et al. found that amlodipine besylate interfered with the interpretation of signal from furabased dyes, as amlodipine and fura-2 have overlapping excitation spectra. Moreover, they found that amlodipine accumulated within the cytoplasm over several minutes of exposure, dominating the fluorescence signal in fura-2–loaded cells, and thereby mimicking a Ca2+ transient. This is consistent with previous studies that amlodipine can cross the plasma membrane and accumulate in intracellular vesicles. 7 For this reason, Bird et al. used the longer wavelength dye Cal-520 to monitor cytosolic Ca2+ in their studies with dihydropyridine CCBs. With this reporter, they found no evidence for direct activation of Ca2+ release-activated Ca2+(CRAC) channels by these drugs. This study highlights the importance of rigorously testing any hypothesis with different techniques or approaches. However, there were more to the findings than simply demonstrating amlodipine artifactually effected Ca2+ transients that likely confounded the interpretation of the earlier study. The authors report complex actions of amlodipine on Ca2 …