Evidence for novel age-dependent network structures as a putative primo vascular network in the dura mater of the rat brain

With chromium-hematoxylin staining, we found evidence for the existence of novel age-dependent network structures in the dura mater of rat brains. Under stereomicroscopy, we noticed that chromium-hematoxylin-stained threadlike structures, which were barely observable in 1-weekold rats, were networked in specific areas of the brain, for example, the lateral lobes and the cerebella, in 4-week-old rats. In 7-week-old rats, those structures were found to have become larger and better networked. With phase contrast microscopy, we found that in 1-week-old rats, chromium-hematoxylin-stained granules were scattered in the same areas of the brain in which the network structures would later be observed in the 4- and 7-week-old rats. Such age-dependent network structures were examined by using optical and transmission electron microscopy, and the following results were obtained. The scattered granules fused into networks with increasing age. Cross-sections of the age-dependent network structures demonstrated heavily-stained basophilic substructures. Transmission electron microscopy revealed the basophilic substructures to be clusters with high electron densities consisting of nanosized particles. We report these data as evidence for the existence of age-dependent network structures in the dura mater, we discuss their putative functions of age-dependent network structures beyond the general concept of the dura mater as a supporting matrix.

Dura Mater: Anatomy and Clinical Implication

The dura mater is of similar embryological origin to the fascial organ. It contains several fibroblasts which make the dura mater a flexible structure. Dura mater is the outermost of the three layers of meninges, a thick and rigid inelastic membrane that covers the brain and spinal cord and that is impermeable to the cerebrospinal fluid. The cranial dura mater in certain respects differs anatomically from the dura material in the spinal cord, and it is important to classify them separately. This article reviews the anatomical structure of spinal and cranial dura mater and its anatomy with muscle, fascia, bone structure and ligaments. Dura mater is a structure in the body that is connected with systemic functions.

Preliminary exploration of the development of a collagenous artificial dura mater for sustained antibiotic release

Background Intracranial infection is one of the most common complications of open craniocerebral injury and of conventional craniotomy in neurosurgery. The presence of blood-brain barrier leads to lower drug concentrations in the cerebrospinal fluid than in the venous blood. Increasing the intravenous dosage or frequency carries the risk of systemic adverse reactions or infections in other parts of the body. Developing an artificial dura mater （ADM） for sustained antibiotic release for use during neurosurgery can solve the problems perfectly. Methods Three types of drug-loaded ADMs made of collagen and containing cefuroxime sodium, ceftriaxone sodium, or norvancomycin were prepared. The antibacterial activity and sustained release characteristics of the ADMs were examined using bacteriostatic and release tests. Results Single-layered collagen based ADMs （40 mm×50 mm×5 mm） containing 18 mg cefuroxime sodium or ceftriaxone sodium were not suitable for continued development because of drug preservation and stability issues. Using smaller ADMs （20 mm30 mm×7 mm）, containing 4.86 mg of norvancomycin, with increased collagen density and a three-layered film with two outer drug-free films above and below the antibiotic layer resulted in sustained cumulative release of 2.91 mg （59.9%） of norvancomycin over 72 hours. The similar factor （f2） comparison method proved that products from a same batch were statistically significant similar （f2 〉50）. Conclusions Artificial ADMs made of collagen can be processed to provide a mature dural repair material for the sustained release of norvancomycin. This system may provide a basis for developing sustained release materials for other drugs.

Electrohydrodynamic Fabrication of Triple-layered Polycaprolactone Dura Mater Substitute with Antibacterial and Enhanced Osteogenic Capability

In the field of dura mater repair,it is essential to employ artificial substitutes mimicking the multilayered microar-chitecture and multiple functions of native dura mater for effective neurosurgery.However,existing artificial dura mater substitutes commonly cause complications because of mismatched structural and mechanical properties as well as the lack of antibacterial activity or osteogenic capability.In this study,a triple-layered dura mater substi-tute was fabricated by electrohydrodynamic(EHD)jetting techniques,including electrospinning and melt-based EHD printing processes.Highly aligned polycaprolactone(PCL)nanofibers loaded with gentamicin sulfate(GS)were prepared by electrospinning to form the inner layer,which can mimic the aligned collagen fibers of the native dura mater.Random PCL-GS nanofibers were then deposited by electrospinning to form the middle layer.They were intended to enhance the mechanical properties of the fabricated scaffolds.The outer layer involv-ing PCL microfibers doped with nano-hydroxyapatite(nHA)at various angles was printed by the melting-based EHD method,which can enhance osteogenic capability and promote the fusion between the dura mater substi-tute and the skull.The tensile strength of the triple-layered drug-loaded biomimetic dura mater substitute was 22.42±0.89 MPa,and the elongation at break was 36.43%±2.00%.The addition of GS endowed the substitutes with an anti-infection property without influencing their cytocompatibility.Furthermore,the incorporation of nHA promoted the osteogenic differentiation of MC3T3-E1 cells seeded on the triple-layered scaffolds.This work offers a promising strategy to manufacture multilayered dura mater substitutes with the desired antibacterial and enhanced osteogenic capability performance,possibly providing a novel candidate for dural tissue repair.

Meningioma originating from the superior petrosal vein without dural attachment:A case report

BACKGROUND Meningioma in the cerebellopontine angle(CPA)without dural attachment is extremely rare.We report a unique case of meningioma derived from the superior petrosal vein without dural attachment.CASE SUMMARY A 44-year-old right-handed woman presented with a two-month history of headache and tinnitus.Brain magnetic resonance imaging showed a well-defined contrast-enhancing lesion in the right CPA without a dural tail sign.Tumor resection was performed using a right retro sigmoid approach.A dural attachment was not seen at the tentorium or posterior surface of the petrous pyramid.The tumor was firmly adherent to the superior petrosal vein.The origin site was cauterized and resected with the preservation of the superior petrosal vein.A diagnosis of meningothelial meningioma was made.The patient’s headache and tinnitus gradually disappeared,and a recurrence was not observed five years after the surgery.CONCLUSION The rare occurrence of meningioma without dural attachment makes it difficult to determine dural attachment before surgery.The absence of dural attachment makes it easy to completely resect such tumors.Vessels related to tumors should be removed carefully,considering the possible presence of tumor stem cells in the microvessels.

Induced dural lymphangiogenesis facilities soluble amyloid-beta clearance from brain in a transgenic mouse model of Alzheimer's disease

Impaired amyloid-β clearance from the brain is a core pathological event in Alzheimer＇s disease.The therapeutic effect of current pharmacotherapies is unsatisfactory,and some treatments cause severe side effects.The meningeal lymphatic vessels might be a new route for amyloid-β clearance.This study investigated whether promoting dural lymphangiogenesis facilitated the clearance of amyloid-β from the brain.First,human lymphatic endothelial cells were treated with 100 ng/m L recombinant human vascular endothelial growth factor-C（rh VEGF-C） protein.Light microscopy verified that rh VEGF-C,a specific ligand for vascular endothelial growth factor receptor-3（VEGFR-3）,significantly promoted tube formation of human lymphatic endothelial cells in vitro.In an in vivo study,200 μg/m L rh VEGF-C was injected into the cisterna magna of APP/PS1 transgenic mice,once every 2 days,four times in total.Immunofluorescence staining demonstrated high levels of dural lymphangiogenesis in Alzheimer＇s disease mice.One week after rh VEGF-C administration,enzyme-linked immunosorbent assay results showed that levels of soluble amyloid-β were decreased in cerebrospinal fluid and brain.The Morris water maze test demonstrated that spatial cognition was restored.These results indicate that the upregulation of dural lymphangiogenesis facilities amyloid-β clearance from the brain of APP/PS1 mice,suggesting the potential of the VEGF-C/VEGFR-3 signaling pathway as a therapeutic target for Alzheimer＇s disease.

人工硬脑膜DuraGen^(TM)植入转归的实验研究

目的通过动物实验,观察人工生物型硬脑膜DuraGenTM植入后的转归过程。方法将DuraGenTM修补于15头实验猪右侧硬膜缺损处,左侧作为对照。在修补后1、3、6个月分别处死5头实验猪,行大体标本、光镜和电镜检查,观察人工生物型硬脑膜修补对硬脑膜缺损的作用。结果新生自体纤维组织逐步建立于植入物内,形成一个由新生纤维组织和植入物支架组织交织在一起的中间态结构。新生纤维组织逐渐增加,植入支架结构逐步吸收并最终被新生纤维组织所替代。结论人工生物型脑膜DuraGenTM具有良好的组织相容性,是目前理想的硬脑膜修补材料。

硬膜替代材料Dura-L移植后的形态学与免疫原性研究

目的研究新型硬膜替代材料Dura-L移植后的形态学与免疫原性。方法选用40只成年雄性家兔,随机等分成5组:A:单侧自体移植无创组,B:单侧自体移植创伤组,C:单侧Dura-L移植加对侧自体移植无创组,D:单侧Dura-L移植加对侧自体移植创伤组,E:单侧阳性对照膜移植无创组。应用显微外科技术在无菌条件下施行硬膜替代手术,将Dura-L移植于C、D组兔脑表面。分别于2周、1个月、3个月应用扫描电镜、免疫荧光、病理学切片检测进行评价。结果2周末、1个月末、3个月末C组、D组与E组间在表面光滑程度、荧光强度、炎性细胞浸润三方面之间的差异具有统计学意义,而与A、B两组间的差异不具有统计学意义。结论Dura-L移植后形态学与家兔硬膜类似,免疫原性低,是一种比较适合的硬膜替代材料。

Effect of visual stimulus locations on pattern-reversal visual evoked potential An epidural electrocorticogram study

To explore the effect of the location of a visual stimulus on neural responses in the primary visual cortex （V1）, a micro-electromechanical system-based microelectrode array with nine channels was implanted on the cerebral dura mater of V1 in adult cats. 2 Hz pattern reversal checkerboard stimul were used to stimulate the four visual quadrants （i.e., upper left, upper right, lower left, and lower right fields）. The results showed that there was a N75 component of the visual evoked potential around 50-80 ms after the onset of a checkerboard stimulus, and the onset of these N75 peaks varied with different stimulus locations. The checkerboard stimuli Jnduced shorter latencJes in the contralateral V1 than in the ipsilateral V1, while the checkerboard stimulus in the upper half visual field induced shorter latencies for N75. These results suggested that the pattern-reversal stimuli induced neural activities in V1 that can be recorded with multichannel microelectrodes, and more detailed temporal and spatial properties can be measured.

Intradural Disc Herniation Can Be Intra-Arachnoid or Extra-Arachnoid: 2 Case Reports with MRI Diagnosis and Non-Surgical Management

Intradural disc herniation is rare and often diagnosed during surgery. We present two patients with the disease, one with an intra-arachnoid type, the other with an extra-arachnoid location. The teaching point of those cases is that this very frequent pathology can take a variety of forms, depending on the structures that are infiltrated. The key point in correctly diagnosing the intradural disc herniation is to look at the angle between the fragment and the dura. Is it pushing it (as in the usual disc herniation), embedded in it (those with the extra-arachnoid type) or does it go through to fall into the CSF (In the intra-arachnoid type)? It could be diagnosed on MRI preoperatively. Contrary to many published cases of intradural disc herniation, the two patients could be managed non-surgically.

Use of Acellular Fish Skin for Dura Repair in an Ovine Model: A Pilot Study

Recently the use of biologic materials as dura mater repair patches has been increasing. The purpose of this study is to assess the basis for efficacy and safety of using a novel fish derived acellular dermis (Kerecis Omega3 DuraTM). In an ovine model a craniotomy under general anaesthesia was performed. A defect was produced in the dural covering of approximately 1 × 2 cm and closed with an onlay technique, with Kerecis Omega3 Dura. The bone defect was covered with the bony flap and the overlying tissues closed in layers. At 2, 5, 8 and 11 weeks the sheep underwent MRI scanning followed by euthanasia, necropsy and histological assessment. MRI images taken at 2, 5, 8 and 11 weeks showed initially moderate inflammatory response, which diminished over time, and at 11 weeks no evidence of inflammation existed. There was evidence of cerebrospinal fluid leakage at no time point. Necropsy revealed some adhesions at 5 and 8 weeks, in particular at 5 weeks, but at 11 weeks there were no adhesions found. From 2 - 11 weeks, there was evidence of initially an inflammatory reaction followed by neodura formation at the defect site through cellular ingrowth and remodeling of the acellular fish skin. Histology showed a histiocytic foreign body reaction initially that subsided over time. As early as 8 weeks there was evidence of neodura formation and by 11 weeks there was a minimal inflammatory response with an intact neodura formed. In this pilot study the Kerecis Omega3 Dura patches performed in a safe and efficacious manner. This new material needs to be fully assessed and compared with other products that are currently on the market in a larger scale animal study.

耳内镜下鼓膜修补术后穿孔再修补的疗效分析

目的 探讨人工硬脑膜和表皮生长因子在耳内镜下鼓膜修补术后鼓膜穿孔再修补中的临床疗效。方法 选择该院耳内镜下鼓膜修补术后复查时仍有鼓膜穿孔未愈合的患者58例,随机分为A组和B组,各29例。A组采用明胶海绵修补鼓膜穿孔,B组采用人工硬脑膜和表皮生长因子修补鼓膜穿孔,每个月复查鼓膜愈合情况,3个月后复查纯间测听。结果 A组修补成功率为34.48%(10/29),B组修补成功率为75.86%(22/29),两组患者比较,差异有统计学意义(P <0.05);A组气骨导差改善(7.32±2.68) dB HL,B组气骨导差改善(21.77±4.65)dB HL,两组患者比较,差异有统计学意义(P <0.05)。结论 人工硬脑膜是合适的鼓膜再生支架,表皮生长因子可促进鼓膜穿孔愈合,两者结合使用是鼓膜再修补的一种可行的治疗方案。

硬脑膜修复生物膜的大鼠原位脑植入局部神经毒性评价方法

目的采用大鼠原位脑植入模型评价硬脑膜修复生物膜的局部神经毒性,旨在建立脑部原位植入局部神经毒性评价方法。方法选择硬脑膜修复生物膜为研究对象,以上市同类产品为对照品,经大鼠原位脑植入,获取包含颅骨、硬脑膜、植入材料及其周围大脑组织的标本。采用苏木精-伊红(hematoxylin-eosin,HE)染色、Fluoro-Jade C(FJC)特殊染色与胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)免疫荧光考察植入物周围脑组织的局部组织学反应、神经元降解退行性变与星形胶质细胞增生来综合评价植入物的潜在神经毒性风险。结果植入4周、13周、26周后,与对照品相比,供试品的局部组织学反应均为无刺激反应;FJC染色单位面积阳性细胞数量不存在显著性差异(P>0.05),提示供试品的神经元降解程度与对照组相比不存在显著性差异;GFAP染色单位面积阳性细胞数量不存在显著性差异(P>0.05),提示供试品的星形胶质细胞增生程度与对照组相比不存在显著性差异。结论可以采用HE染色、FJC特殊染色与GFAP免疫荧光染色联合评价硬脑膜修复生物膜经大鼠原位脑植入后的局部神经毒性。

大鼠硬脑膜对颅骨成骨增强的影响

背景:硬脑膜与颅骨在结构和功能上联系密切,原代提取硬脑膜和颅骨细胞并将二者共培养的研究几乎没有,利用原代细胞探究硬脑膜对颅骨的影响具有创新性,有望为临床治疗提供理论依据。目的:原代提取大鼠硬脑膜和颅骨细胞,观察硬脑膜对颅骨增殖和分化能力的影响,初步了解Twist1在其中的作用。方法:利用酶解法与组织块法相结合的方法原代提取出生3 d内大鼠硬脑膜细胞和颅骨细胞,免疫荧光染色鉴定所提取细胞,茜素红染色鉴定与评估颅骨细胞及其矿化能力,real-time PCR检测硬脑膜细胞与颅骨细胞共培养后,颅骨细胞增殖与成骨相关基因表达及Twist1的表达。结果与结论:①形态学:所提取硬脑膜细胞形态特征与成纤维细胞一致,成骨细胞呈纺锤形。②细胞鉴定:免疫荧光染色显示,所提取硬脑膜细胞表达高水平的波形蛋白,颅骨细胞表达高水平的碱性磷酸酶;成骨诱导28 d颅骨细胞茜素红染色观察到明显的矿化结节。③real-time PCR检测显示,与对照组比较,共培养组PCNA、碱性磷酸酶、RUNX2 mRNA表达升高(P<0.01);Twist1 mRNA表达降低(P<0.01)。④结果表明,原代提取的颅骨细胞具有较强的矿化能力,硬脑膜是促进颅骨的生长发育与成骨分化的重要因素,且Twist1在该过程中发挥重要作用。

颅缝发育与颅缝早闭的分子机制

颅骨的发育依赖于颅缝(cranial suture)正常的骨供给,期间颅缝的间充质干细胞经历系统地增殖和成骨分化以保证骨的正常生长。遗传因素或外界干扰则可能引起干细胞的过度成骨分化,导致颅骨的过早闭合,称为颅缝早闭。颅缝细胞与细胞外基质、骨膜以及脑膜共同构成颅缝微环境(niche)。它们相互调节以保证颅缝的正常发育。临床研究发现,绝大多数颅缝早闭(craniosynostosis)患者都伴有硬脑膜和细胞外基质(extracellular matrixc,ECM)的异常。许多研究也发现,作用于颅缝的异常外界机械刺激也可能导致颅缝发育的异常。考虑到颅缝发育受多方面因素影响,本篇综述将介绍近年来有关颅缝微环境异常,以及机械力在调控颅缝发育中的研究进展,总结颅缝早闭发生的分子机制和目前研究方向,旨在为该病的诊断治疗提供新的思路。

硬脑膜/颅缝间充质干细胞对颅骨发育的影响

颅缝复合体由具有间充质的纤维组织、成骨前沿、下面的硬脑膜和上覆的骨膜组成。硬脑膜是一层保护大脑和脊髓的纤维结缔组织,拥有血管和淋巴管,对早期发育过程中颅骨成骨的进展,后期颅骨的形态和颅缝状态十分重要。颅缝间充质干细胞主要存在于颅缝中,具有增殖、分化为成骨细胞、生成颅骨和增强颅骨损伤后修复的能力。了解颅缝间充质干细胞与硬脑膜的作用机制,对颅骨生长发育和颅脑疾病的治疗非常重要。该文对硬脑膜和颅缝间充质干细胞在颅骨发育中的机制进行综述。

骨形态发生蛋白2在小儿颅骨缺损自行修复中的作用

颅脑外伤在小儿各类外伤中占据首位。去骨瓣减压术为神经外科常见减少颅内压的手术方式,颅骨缺失会导致患儿脑组织缺少颅骨保护,颅骨作为脑组织最直接的保护屏障,若缺损不及时修补会因体位、情绪和腹压等会导致脑组织在颅内发生移动,从而造成脑穿通性畸形、癫痫发作和脑变性萎缩等疾病。小儿有好动、依从性差、自我保护能力差等特点,更容易形成二次伤害。小儿处于生长发育期,缺乏颅骨的保护,颅脑容易受到二次伤害,还会影响患儿神经系统的正常发育,造成患儿智力低下,神经系统发育不完善等相关并发症,所以重建颅骨的完整对患儿的生长发育至关重要。未成熟硬脑膜对颅骨的发育和缺损修复有重要作用,2岁以下的儿童能够修复巨大的颅骨缺损,而成年人则缺乏这种内源性能力。幼龄动物骨缺损中骨形态发生蛋白2(BMP2)上调,表明BMP2在骨组织再生中具有重要作用。许多生物调节因子可调控BMP2的活性。该综述就BMP2在小儿颅骨缺损修复中的研究现状做总结。

硬脑膜在颅骨/脑膜/脑组织系统生长发育中的作用机制研究进展

硬脑膜是贴覆在颅骨内表面且包绕大脑的一层质韧的纤维结缔组织膜,作为脑组织与颅骨间的缓冲性桥梁结构,其生理功能及在颅骨发育和修复中的作用一直是研究的热点。近年来研究发现,硬脑膜在颅骨的生长过程中不仅直接参与颅骨的发育,还分泌多种控制中枢神经系统发育的细胞因子,两者间有丰富的物质交换与细胞迁移。该文从硬脑膜在颅骨发育及修复中的作用进行综述,为进一步发现硬脑膜在颅骨发育及修复中的相关机制提供线索。

人工硬脑膜在硬膜下电极埋置术中的应用

目的探讨使用人工硬脑膜修补替代自体硬脑膜原位缝合在降低硬膜下电极埋置术后并发症发生率中的作用。方法回顾性分析2008年1月至2021年12月进行硬膜下电极埋置术的308例病人的临床资料。2008年1月至2013年12月手术的163例采取自体硬脑膜原位缝合(自体硬脑膜组),2014年1月至2021年12月手术的145例采取人工硬脑膜修补(人工硬脑膜组)。两组手术评估、手术操作均为同一治疗团队完成,除对硬脑膜处理方式改变之外,其余手术流程保持一致。结果自体硬脑膜组术后继发颅内出血13例(7.97%)、脑脊液漏22例(13.50%)、颅内感染5例(3.07%);人工硬脑膜组术后继发颅内出血4例(2.76%)、脑脊液漏7例(4.83%)、颅内感染3例(2.07%)。人工硬脑膜组术后继发性颅内出血发生率、脑脊液漏发生率均明显低于自体硬脑膜组(P<0.045)。两组术后颅内感染发生率无统计学差异(P>0.045)。结论在硬膜下电极埋置术中使用人工硬脑膜修补替代自体硬脑膜原位缝合,在降低继发颅内出血、脑脊液漏方面具有明显的优势。

聚乳酸凝胶预防硬膜外瘢痕粘连的实验研究

目的 探讨新型生物可吸收材料聚乳酸凝胶 (polyactic acid glue,PL A- G)预防椎板切除术后硬膜外瘢痕粘连的作用。 方法 切除 2 4只成年日本大耳白兔的 L2 和 L5椎板 ;在 L5外露的硬膜及神经根表面喷涂液态PL A- G形成胶冻膜 ,为实验组 ;L2 处只做椎板切除 ,为自身空白对照组。术后 2、4、6、8、10及 12周随机处死各 4只兔 ,取标本行大体、组织学及超微结构的观察。 结果 2周时实验组 PL A- G未降解为机械屏障膜 ,硬膜与外侧瘢痕组织 (scartissue,ST)间有明显间隙 ,光镜下显示间隙内无细胞 ;对照组为血肿覆盖较易分开 ,硬膜与 ST间有血细胞团块 ,成纤维细胞 (fibroblast,FB)增生活跃。 4周时实验组 PL A- G部分降解 ,机械屏障及间隙存在 ,光镜下 ST中 FB增多 ;对照组为较多质脆 ST与硬膜广泛粘连 ,光镜下可见组织细胞浸润间隙 ,ST内 FB明显多于实验组。 6周时实验组 PL A- G完全降解 ,少量 ST与硬膜无粘连 ,光镜下 FB已减少 ;对照组有大量质韧难以从硬膜分离的 ST,FB继续增生活跃。 8、10及 12周时实验组 ST与硬膜无粘连 ;对照组 ST与硬膜粘连严重 ,光镜下见 ST和硬膜粘连紧密伴毛细血管再造。超微结构观察 :4周时实验组 FB的粗面内质网较稀疏 ,分泌胶原纤维少 ;对照组 FB的粗面内质网极丰富 ,胶?