Pathomechanism of loss of elasticity and hypertrophy of lumbar ligamentum flavum in elderly patients with lumbar spinal canal stenosis
Pathomechanism of loss of elasticity and hypertrophy of lumbar ligamentum flavum in elderly patients with lumbar spinal canal stenosis
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DOI：
10.1097/brs.0b013e31815b650f
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发表时间：
2007-12-01
期刊：
影响因子：
3
通讯作者：
Yasui, Natsuo
中科院分区：
文献类型：
--
作者：
Kosaka, Hirofumi;Sairyo, Koichi;Yasui, Natsuo
研究设计.腰椎黄韧带的组织学、生物学和免疫组化评估。阐明老年人腰椎黄韧带（LF）弹性丧失和肥大的病理机制。老年患者最常见的脊柱疾病是腰椎管狭窄症，引起腰痛和下肢疼痛，以及轻瘫。椎管狭窄部分是由于LF肥大所致。虽然组织学和生物学文献对此主题是可用的，但LF的弹性损失和肥大的病理机制仍然未知。取1例胎儿、5例青年和5例老年LF进行组织学研究。对每种LF进行苏木精和伊红、阿辛蓝、Masson三色和Elastica货车Gieson染色。收集9例LF，应用真实的时间RT-PCR技术定量检测LF中I型胶原和弹性蛋白mRNA的表达。在胎儿的LF中，弹性纤维约占整个面积的75%。在年轻组和老年组的LF的硬脑膜方面，该比例也约为75%;然而，背侧方面的比例随着年龄的增长而下降。通过阿尔新蓝和II型胶原免疫组织化学显示，几乎一半显示弹性纤维损失的区域被转化为产生II型胶原和蛋白多糖的软骨组织。该区域用EV未染黑，用AB染色未染蓝，用T染色阳性染蓝，表明瘢痕形成。青年组和老年组的正常硬脑膜层面积分别为18.0 +/- 2.3和33.8 +/- 4.3（mm（2））。相应地，背侧异常层为3.2 +/- 0.8和18.0 +/- 10.2（mm 2）。弹性蛋白mRNA与年龄呈较强的相关性（r = 0.44），但斜率非常平缓。Ⅰ型胶原mRNA与年龄呈极强的相关性（r = 0.80）。与年轻患者的LF相比，斜率更陡，65岁左右的值达到1000%（10倍）。弹性蛋白mRNA与厚度呈弱相关（r = 0.36），斜率较平缓。I型胶原mRNA与厚度呈较强的相关性（r = 0.52）。与薄LF相比，斜率更陡，并且在6.5（mm）附近达到1000%（10倍）。老年人LF弹性下降是由于弹性纤维的损失和随之而来的背侧胶原纤维的增加。LF肥大可能是由于正常的弹性层以及异常的胶原层增厚。
Study Design. A histologic, biologic, and immunohistochemical assessment using human samples of lumbar ligamentum flavum.Objective. To clarify the pathomechanism of loss of elasticity and hypertrophy of the lumbar ligamentum flavum (LF) in the elderly population.Summary of Background Data. The most common spinal disorder in elderly patients is lumbar spinal canal stenosis, causing low back and leg pain, and paresis. Canal narrowing, in part, results from hypertrophy of the LF. Although histologic and biologic literature on this topic is available, the pathomechanism of loss of elasticity and hypertrophy of the LF is still unknown.Methods. One fetus, 5 young, and 5 elderly LF were obtained for histologic study. Hematoxylin and eosin, Alcian blue, Masson Trichrome, and Elastica Van Gieson stains were performed for each LF. Nine LF were collected and were used for biologic study of real time RT-PCR to quantitatively measure mRNA expression of Type I collagen and elastin in each LF.Results. In the LF of the fetus, elastic fibers accounted for about 75% of the entire area. In the dural aspect of the LF in the young and elderly group, the ratio was also around 75%; however, the ratio of the dorsal aspect decreased with age. Almost half of the area showing loss of elastic fibers was shown to be converted to cartilaginous tissue producing Type II collagen and proteoglycan by Alcian blue and Type II collagen immunohistochemistry. The area, which did not stain black with EV nor blue with AB stain, was positively stained blue with T stain, indicating scarring. The area of the normal dural layer was 18.0 +/- 2.3 and 33.8 +/- 4.3 (mm(2)), for young and elderly group, respectively. Accordingly, it was 3.2 +/- 0.8 and 18.0 +/- 10.2 ( mm2), for the dorsal abnormal layer. Elastin mRNA showed a relatively strong correlation (r = 0.44) with age; however, the slope was very gentle. Type I collagen mRNA showed a very strong correlation ( r = 0.80) with age. The slope was steeper, and the value reached at 1000% (10-fold) around 65 years old when compared with the LF from younger patient. Elastin mRNA showed a weak correlation (r = 0.36) with thickness, and the slope was gentle. Type I collagen mRNA showed relatively strong correlation (r = 0.52) with thickness. The slope was steeper, and the line reached at 1000% (10-fold) around 6.5 (mm) when compared with a thin LF.Conclusion. Decreased elasticity of LF in the elderly is due to the loss of elastic fibers and a concomitant increase of collagenous fibers in the dorsal aspect. LF hypertrophy could be due to the thickening of the normal elastic layer as well as of the abnormal collagenous layer.