Dainese Luca, Polvani Gianluca, Barili Fabio, Maccari Francesca, Guarino Anna, Alamanni Francesco, Zanobini Marco, Biglioli Paolo, Volpi Nicola
Department of Cardiac and Vascular Surgery, Centro Cardiologico Monzino, IRCCS University of Milan, Milan, Italy.
Clin Chem Lab Med. 2007;45(3):361-6. doi: 10.1515/CCLM.2007.061.
The levels and fine structure of complex polysaccharides, glycosaminoglycans (GAGs), were determined in segments of the posterior mitral valve leaflet (MVL) taken from 15 patients affected by mitral regurgitation and degenerative disease and were compared with segments from 15 multiorgan donors.
MVL GAGs were analyzed by agarose gel electrophoresis, and by HPLC and fluorophore-assisted carbohydrate electrophoresis to evaluate disaccharide patterns after treatment with chondroitinase ABC.
GAGs from the control group were composed of approximately 37% hyaluronic acid and 63% chondroitin sulfate/dermatan sulfate with a charge density of approximately 0.61. Chondroitin sulfate/dermatan sulfate polymers contained approximately 23% of the disaccharide sulfated in position 6 on N-acetyl-galactosamine, approximately 38% of the 4-sulfated disaccharide and approximately 2% of the non-sulfated disaccharide (with a 4-sulfated/6-sulfated ratio of 1.7). The total amount of GAGs was 0.66 microg/mg tissue. The total amount of GAGs in patients suffering from mitral regurgitation and degenerative disease was approximately 51.5% higher (although the difference was not significant, probably because of the low number of subjects enrolled in the study). However, significantly higher hyaluronic acid content (approx. +38%, p<0.05) and lower sulfated GAG content (approx. -21%, p<0.005) were demonstrated. As a consequence, the total charge density decreased by approximately 23% (p<0.005). This macro-modification of GAG composition was also followed by a micro-alteration of the structure of the sulfated polysaccharides, in particular with a significant decrease in the 4-sulfated disaccharide (and a parallel increase in hyaluronic acid content) with no modification of the percentage of the 6-sulfated and non-sulfated disaccharides (with a significant decrease in the 4-/6-sulfated ratio).
We assume that changes in the relative amount and distribution of GAGs in posterior MVL in subjects suffering from mitral regurgitation and degenerative disease are consistent with a decrease in the tension to which these tissues are subjected and with an abnormal matrix microstructure capable of influencing the hydration and of conditioning the mechanical weakness of these pathological tissues.
测定了15例二尖瓣反流和退行性疾病患者的二尖瓣后叶（MVL）节段中复合多糖、糖胺聚糖（GAGs）的水平和精细结构，并与15例多器官供体的节段进行了比较。
通过琼脂糖凝胶电泳、高效液相色谱和荧光辅助碳水化合物电泳分析MVL GAGs，以评估用软骨素酶ABC处理后的二糖模式。
对照组的GAGs由约37%的透明质酸和63%的硫酸软骨素/硫酸皮肤素组成，电荷密度约为0.61。硫酸软骨素/硫酸皮肤素聚合物含有约23%在N-乙酰半乳糖胺6位硫酸化的二糖、约38%的4-硫酸化二糖和约2%的非硫酸化二糖（4-硫酸化/6-硫酸化比率为1.7）。GAGs的总量为0.66μg/mg组织。二尖瓣反流和退行性疾病患者的GAGs总量高出约51.5%（尽管差异不显著，可能是因为研究纳入的受试者数量较少）。然而，透明质酸含量显著更高（约+38%，p<0.05），硫酸化GAG含量更低（约-21%，p<0.005）。因此，总电荷密度下降了约23%（p<0.005）。GAG组成的这种宏观变化还伴随着硫酸化多糖结构的微观改变，特别是4-硫酸化二糖显著减少（透明质酸含量平行增加），而6-硫酸化和非硫酸化二糖的百分比没有改变（4-/6-硫酸化比率显著降低）。
我们认为，二尖瓣反流和退行性疾病患者后MVL中GAGs相对数量和分布的变化与这些组织所受张力的降低以及能够影响水合作用并导致这些病理组织机械性脆弱的异常基质微观结构一致。
