The relationship between compensatory hyperplasia of the myodural bridge complex and reduced compliance of the various structures within the cranio-cervical junction

Resveratrol ameliorates pathological fibrosis of the myodural bridge by regulating the SIRT3/TGF-β1/Smad pathway

Purpose

Pathological fibrosis of the myodural bridge (MDB) affects cerebrospinal fluid circulation. However, no optimal drug treatments are available. We aimed to explore the antifibrotic effect of resveratrol on bleomycin-induced pathological fibrosis of the MDB and its underlying mechanisms.

Methods

Genes common to the potential targets of resveratrol were determined using network pharmacology, genes related to muscle and tendon fibrosis were acquired from the GeneCards database, and genes related to MDB development were determined using Venny. These genes were considered potential resveratrol treatment targets in bleomycin-induced pathological fibrosis of the MDB and were annotated using bioinformatics methods. We validated the intersected genes using quantitative real-time polymerase chain reaction (qRT-PCR) and performed molecular docking analysis to calculate the binding activity between the target gene and resveratrol. Hematoxylin and eosin and Masson staining were used to detect the morphological changes in bleomycin-induced fibrosis of the MDB following resveratrol treatment. We used qRT-PCR and immunohistochemistry to evaluate the expression of the sirtuin 3 (SIRT3)/transforming growth factor-β1 (TGF-β1)/Smad pathway and the profibrotic markers α-smooth muscle actin (α-SMA) and Collagen Ⅰ.

Results

Through network pharmacology and bioinformatics analyses, we identified four core intersected genes, and SIRT3 expression was validated using qRT-PCR. Molecular docking analysis revealed that resveratrol had good binding affinity for SIRT3. Resveratrol ameliorated morphological abnormalities in bleomycin-induced pathological fibrosis of the MDB by inhibiting fibroblast activation and excessive collagen fiber deposition. Resveratrol exerted its antifibrotic effect by regulating the SIRT3/TGF-β1/Smad pathway.

Conclusion

Resveratrol has an antifibrotic effect in bleomycin-induced pathological fibrosis of the MDB in vivo and may be considered a novel therapeutic strategy.

Evidence for chronic headaches induced by pathological changes of myodural bridge complex

Clinical studies have shown that there may be a certain relationship between pathological changes of the myodural bridge complex (MDBC) and chronic headaches of unknown cause. But there is still a lack of experimental evidence to explain the possible mechanism. This study aims to further confirm this relationship between MDBC and chronic headaches and explore its potential occurrence mechanism in rats. Bleomycin (BLM) or phosphate-buffered saline (PBS) was injected into the myodural bridge fibers of rats to establish the hyperplastic model of MDBC. After 4 weeks, the occurrence of headaches in rats was evaluated through behavioral scores. The immunohistochemistry staining method was applied to observe the expression levels of headache-related neurotransmitters in the brain. Masson trichrome staining results showed that the number of collagen fibers of MDBC was increased in the BLM group compared to those of the other two groups. It revealed hyperplastic changes of MDBC. The behavioral scores of the BLM group were significantly higher than those of the PBS group and the blank control group. Meanwhile, expression levels of CGRP and 5-HT in the headache-related nuclei of the brain were increased in the BLM group. The current study further confirms the view that there is a relationship between pathological changes of MDBC and chronic headaches of unknown cause. This study may provide anatomical and physiological explanations for the pathogenesis of some chronic headaches of unknown cause.

The growth and developmental of the myodural bridge and its associated structures in the human fetus

Myodural bridge (MDB) is a dense connective tissue between suboccipital muscle and dura mater. However, there are few reports on the development and maturation of the human MDB. This study aims to explore the developmental relationship between suboccipital muscle and MDB. 30 head and neck specimens from human fetuses (F) ranging from the 12th to 41st week (W) were made into histological sections. The F12W sections showed evidence that the dura mater dominated by fibroblasts, attached to the posterior atlanto-axial membrane (PAAM) which completely sealed the atlanto-axial space. In the F13W stage, myofibrils of the suboccipital muscle fibers increased significantly in number. At the F14W stage, a gap was observed at the caudal end of the PAAM. Numerous myodural bridge-like structures were observed blending into the dura mater through the gap. At the F19W stage, muscle cells mature. Starting at the F21W stage, the MDB were observed as fibroblasts that cross the atlanto-axial interspace and attach to the dura mater. Therefore, the traction generated by the suboccipital muscles seems to promote the maturity of MDB. This study will provide new morphological knowledge to support future research on the function of the human MDB and regulating the development mechanism of MDB.

Dynamic asymmetry in cerebrospinal fluid pressure: An indicator of regional differences in compliance

Background

Dural compliance influences the shape and magnitude of the cerebrospinal fluid (CSF) pulsations. In humans, cranial compliance is approximately 2× greater than spinal compliance; the differential has been attributed to the associated vasculature. In alligators, the spinal cord is surrounded by a large venous sinus, which suggests that the spinal compartment may have higher compliance than is found in mammals.

Methods

Pressure catheters were surgically implanted into the cranial and spinal subdural spaces of eight subadult American alligators (Alligator mississippiensis). The CSF was propelled through the subdural space by orthostatic gradients and rapid changes in linear acceleration.

Results

CSF pressure recordings taken from the cranial compartment were consistently, and significantly, larger than those taken from the spinal compartment. After the myodural bridge of Alligator was surgically released, the asymmetry in CSF pressure was decreased.

Conclusion

Unlike the situation in humans, the spinal compartment of Alligator has greater compliance than the cranial compartment, presumably due to the presence of the large spinal venous sinus surrounding the dura. The change in CSF pressures after myodural surgical release supports the hypothesis that the myodural bridge functions, at least in part, to modulate dural compliance and the exchange of CSF between the cranial and spinal compartments.

Effectiveness of craniosacral therapy in the human suboccipital region on hamstring muscle: A meta-analysis based on current evidence

BACKGROUND

Craniosacral therapy (CST) has remained controversial in the treatment of musculoskeletal disorders. To our knowledge, there is no larger sample size of research to demonstrate the effectiveness of craniosacral therapy in the human suboccipital region on hamstring muscle.

METHODS

To study whether the CST in the human suboccipital region could have a remote effect on the flexibility of the hamstring muscles, the Cochrane Library, Medline/Pubmed, CNKI, Embase, and Google Scholar were searched. Clinical trials assessing the effects of CST in short hamstring syndrome patients were eligible. Mean differences (MD) and 95% confidence intervals (CI) were calculated for the straight leg raise test (primary outcomes). The quality of the included studies was assessed using the Newcastle-Ottawa Scale. RevMan 5.3 software was used for data analysis.

RESULTS

Five controlled trials with a total of 238 participants were included. CST could effectively relieve the symptoms of short hamstring syndrome patients [the overall MD -9.47, 95% confidence interval (CI) -15.82 to -3.12, P < .000001]. The CST was better than the proprioceptive neuromuscular facilitation technique (MD 3.09, 95% CI 1.48-4.70, P = .0002). Sensitivity analysis shows that the frequency of treatment and who did the experiment might be the main sources of impact results.

CONCLUSION

CST could change the flexibility of the hamstring muscles. CST had a better curative effect when compared to proprioceptive neuromuscular facilitation technique on the hamstring muscles.

Compromised Cranio-Spinal Suspension in Chiari Malformation Type 1: A Potential Role as Secondary Pathophysiology

In Chiari Malformation Type I (CM1), low-lying tonsils obstruct the cisterna magna at the foramen magnum, thereby compromising the essential juncture between the cranial and spinal compartments. The anatomical obstruction of the cisterna magna inhibits bi-directional CSF flow as well as CSF pulse pressure equilibration between the intracranial compartment and the intraspinal compartment in response to instances of increased intracranial pressure. Less understood, however, are the roles of the spinal cord suspension structures at the craniocervical junction which lend viscoelastic support to the spinal cord and tonsils, as well as maintain the anatomical integrity of the cisterna magna and the dura. These include extradural ligaments including the myodural bridges (MDBs), as well as intradural dentate ligaments and the arachnoid framework. We propose that when these elements are disrupted by the cisterna magna obstruction, tonsillar pathology, and altered CSF dynamics, there may arise a secondary pathophysiology of compromised and dysfunctional cranio-spinal suspension in CM1. We present intraoperative images and videos captured during surgical exposure of the craniocervical junction in CM1 to illustrate this proposal.