Department of Cardiac Surgery, Medical University of Silesia, School of Medicine in Katowice, Katowice, Poland.
Eur J Cardiothorac Surg. 2022 May 27;61(6):1423-1429. doi: 10.1093/ejcts/ezac074.
Perivascular adipose tissue (PVAT) surrounding the human internal thoracic artery exhibits anticontractile and vasorelaxing properties associated with the adipocyte-derived relaxing factor (ADRF). The goal of our study was to assess if perivascular tissue of the human radial artery (RA) also exhibits such anticontractile/vasorelaxant properties. It could be especially relevant in preventing RA spasms.
The study was performed on isolated segments of human pedicled RA. Its skeletonized fragments were suspended on stainless steel wire hooks and gradually contracted with serotonin to establish the concentration-effect relationship in the presence/absence of PVAT. Skeletonized arterial segments were precontracted with a single dose of 10-6 M serotonin (EC80). The 5-ml PVAT aliquots (from PVAT incubated in Krebs-Henseleit solution) were transferred to the RA tissue bath resulting in its relaxation. Subsequently, we investigated if ADRF is dependent on endothelial vasorelaxants (nitric oxide and prostacyclin). We attempted to find the potassium channel responsible for mediating the activity of ADRF using different potassium channel blockers.
RA without PVAT contracted more strongly in response to serotonin compared to RA with PVAT [Emax: 108.3 (20.2) vs 76.1 (13.5) mN]. The PVAT aliquot relaxed precontracted RA rings at 43% (2.4%) [72.2 (15.6) to 41.0 (5.6) mN]. ADRF is independent of endothelial vasorelaxants; hence, the addition of NG-monomethyl-l-arginine and indomethacin did not change the vasorelaxant response. Neither of the potassium channel blockers participated in the activity of ADRF.
PVAT of human RA exhibits anticontractile/vasorelaxant properties that are inherently associated with ADRF secretion. We confirmed the endothelial-independent mechanism of the activity of ADRF. However, we failed to find the potassium channel responsible for the action of ADRF.
人胸廓内动脉周围的血管周脂肪组织（PVAT）表现出与脂肪细胞衍生的舒张因子（ADRF）相关的抗收缩和血管舒张特性。我们研究的目的是评估人类桡动脉（RA）的血管周组织是否也具有这种抗收缩/血管舒张特性。这在预防 RA 痉挛方面可能特别重要。
本研究在分离的人带蒂 RA 段上进行。将其去骨碎片悬挂在不锈钢丝钩上，并逐渐用 5-羟色胺收缩，以在存在/不存在 PVAT 的情况下建立浓度-效应关系。用 10-6 M 5-羟色胺（EC80）的单次剂量预收缩去骨动脉段。将 5ml 的 PVAT 等分试样（从在 Krebs-Henseleit 溶液中孵育的 PVAT 转移）转移到 RA 组织浴中，导致其舒张。随后，我们研究了 ADRF 是否依赖于内皮血管舒张剂（一氧化氮和前列环素）。我们试图使用不同的钾通道阻滞剂找到介导 ADRF 活性的钾通道。
与有 PVAT 的 RA 相比，无 PVAT 的 RA 对 5-羟色胺的反应性更强，收缩更强[Emax：108.3（20.2）对 76.1（13.5）mN]。PVAT 等分试样松弛预收缩的 RA 环 43%（2.4%）[72.2（15.6）至 41.0（5.6）mN]。ADRF 不依赖于内皮血管舒张剂；因此，加入 NG-单甲基-L-精氨酸和吲哚美辛不会改变血管舒张反应。钾通道阻滞剂均未参与 ADRF 的活性。
人 RA 的 PVAT 表现出抗收缩/血管舒张特性，这些特性与 ADRF 的分泌内在相关。我们证实了 ADRF 活性的内皮独立机制。然而，我们未能找到负责 ADRF 作用的钾通道。
