Dritsa Vassiliki, Pissaridi Katerina, Koutoulakis Emmanouil, Mamarelis Ioannis, Kotoulas Christoforos, Anastassopoulou Jane
National Technical University of Athens, Chemical Engineering Department, Radiation Chemistry and Biospectroscopy, Zografou Campus, 15780 Zografou, Athens, Greece.
In Vivo. 2014 Jan-Feb;28(1):91-8.
In the present study fourier transform infrared (FT-IR) spectroscopy was used to study the mechanism of pathogenesis of aortic valve calcification. The high intensity bands of vCH3 and vCH2 groups of lipids and phospholipids of membranes, in the spectral region 3000-2800 cm(-1), show the high concentration of lipids and fatty components in aortic valve, resulting from degradation of the main aliphatic chain of the membranes, with a change of their permeability and fluidity. The presence of bands at 3075 and 1744 cm(-1), assigned to olefinic (v=CH) and aldehyde carbonyl groups, respectively, implies that reactive oxygen species are involved in the initiation of peroxidation of the lipids and phospholipids. These latter bands are related to the oxidative stress of the patients. From the shifts of bands to lower frequencies of the characteristic absorption bands of amide I and amide II, it is suggested that the proteins change their secondary structure from α-helix to β-sheets and random coil due to modifications of collagen, associated with the permeability of aortic valve atherosclerosis. From the spectral region 1150-900 cm(-1), where the characteristic stretching vibration bands of the phosphate groups (vPO4(-3)) absorb, the calcified aortic valve was found to contain biological hydroxyapatite (Ca10(PO4)6(OH)2), as well as amorphous hydroxyapatite (Ca5(PO4)xOH) and CaHPO4. These findings are in agreement with scanning electron microscopy energy-dispersive X-ray analysis and X-ray diffraction analyses. SEM micrographs show that the valves are rich in fibrils and that the protein-protein cross-linked chemical bonds seem to be the points of initiation of calcification.
在本研究中，采用傅里叶变换红外（FT-IR）光谱法研究主动脉瓣钙化的发病机制。在3000 - 2800 cm⁻¹光谱区域，膜脂质和磷脂的vCH₃和vCH₂基团的高强度谱带表明主动脉瓣中脂质和脂肪成分浓度较高，这是由于膜主脂肪链降解，导致其通透性和流动性发生变化所致。分别归属于烯烃（v = CH）和醛羰基的3075和1744 cm⁻¹处谱带的存在，意味着活性氧参与了脂质和磷脂过氧化的起始过程。这些谱带与患者的氧化应激有关。从酰胺I和酰胺II特征吸收谱带向低频的位移表明，由于与主动脉瓣动脉粥样硬化通透性相关的胶原蛋白修饰，蛋白质的二级结构从α-螺旋转变为β-折叠和无规卷曲。在1150 - 900 cm⁻¹光谱区域，磷酸基团（vPO₄⁻³）的特征伸缩振动谱带在此处吸收，发现钙化的主动脉瓣含有生物羟基磷灰石（Ca₁₀(PO₄)₆(OH)₂），以及无定形羟基磷灰石（Ca₅(PO₄)ₓOH）和磷酸氢钙。这些发现与扫描电子显微镜能量色散X射线分析和X射线衍射分析结果一致。扫描电子显微镜图像显示瓣膜富含纤维，蛋白质 - 蛋白质交联化学键似乎是钙化起始点。
