Renal Physiology Laboratory, Department of Nephrology and Hypertension, Meir Medical Center, Kfar-Saba and Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
Nephrol Dial Transplant. 2009 Nov;24(11):3306-12. doi: 10.1093/ndt/gfp354. Epub 2009 Jul 18.
Recent studies have suggested that vitamin D and an imbalance in calcium homeostasis may have an impact on the cardiovascular system. The aim of this study was to assess the impact of different concentrations of extracellular Ca(2+) on human umbilical vein cord endothelial cells (HUVEC) by measuring its effect on parameters involved in the pathogenesis of vascular inflammatory responses.
HUVEC were grown in the 3.5, 4.5 or 5.8 mg/dL concentration of extracellular Ca(2+) for 2-3 weeks. Expression of adhesion molecules was analysed by flow cytometry. Endothelial nitric oxide synthase (eNOS), receptor of advanced glycation end-product (RAGE) and interleukin-6 (IL-6) mRNA expressions were determined by real-time PCR. eNOS, inhibitor kappa Balpha (IkappaBalpha) and phosphorylated IkappaBalpha protein levels by Western blot, eNOS activity by conversion of [(14)C]-arginine to [(14)C]-citrulline, IL-6 and osteoprotegerin (OPG) secretion by ELISA and DNA-binding activity of nuclear factor kappa B (NFkappaB)-p65 were assayed colorimetrically in nuclear extracts.
In the presence of low Ca(2+) (3.5 mg/dL), protein expressions and activity of eNOS were diminished, while the protein expressions of intercellular adhesion molecule-1 (ICAM-1), as well as the mRNA expressions of RAGE and IL-6, were elevated. The protein secretions of IL-6 and OPG were also stimulated in low Ca(2+) concentration. At this concentration, the DNA-binding activity of NFkappaB was enhanced, probably due to the decreased level of IkappaBalpha.
These results suggest that lower extracellular ionized Ca(2+) may play a relevant role in modifying endothelial cells functions.
最近的研究表明，维生素 D 和钙稳态失衡可能对心血管系统有影响。本研究旨在通过测量其对血管炎症反应发病机制相关参数的影响，评估不同浓度细胞外 Ca(2+)对人脐静脉内皮细胞（HUVEC）的影响。
HUVEC 在 3.5、4.5 或 5.8 mg/dL 浓度的细胞外 Ca(2+)中培养 2-3 周。通过流式细胞术分析粘附分子的表达。通过实时 PCR 测定内皮型一氧化氮合酶（eNOS）、晚期糖基化终产物受体（RAGE）和白细胞介素-6（IL-6）的 mRNA 表达。通过 Western blot 测定 eNOS、抑制剂 kappa Balpha（IkappaBalpha）和磷酸化 IkappaBalpha 蛋白水平，通过 [(14)C]-精氨酸转化为 [(14)C]-瓜氨酸测定 eNOS 活性，通过 ELISA 测定 IL-6 和骨保护素（OPG）分泌，通过比色法测定核提取物中核因子 kappa B（NFkappaB）-p65 的 DNA 结合活性。
在低 Ca(2+)（3.5 mg/dL）存在下，eNOS 的蛋白表达和活性降低，而细胞间粘附分子-1（ICAM-1）的蛋白表达以及 RAGE 和 IL-6 的 mRNA 表达升高。在低 Ca(2+)浓度下，IL-6 和 OPG 的蛋白分泌也受到刺激。在该浓度下，NFkappaB 的 DNA 结合活性增强，可能是由于 IkappaBalpha 水平降低所致。
这些结果表明，较低的细胞外离子化 Ca(2+)可能在修饰内皮细胞功能方面发挥相关作用。
