Altered habenular connectivity in chronic low back pain: An fMRI and machine learning study.

The habenula has been implicated in the pathogenesis of pain and analgesia, while evidence concerning its function in chronic low back pain (cLBP) is sparse. This study aims to investigate the resting-state functional connectivity (rsFC) and effective connectivity of the habenula in 52 patients with cLBP and 52 healthy controls (HCs) and assess the feasibility of distinguishing cLBP from HCs based on connectivity by machine learning methods. Our results indicated significantly enhanced rsFC of the habenula-left superior frontal cortex (SFC), habenula-right thalamus, and habenula-bilateral insular pathways as well as decreased rsFC of the habenula-pons pathway in cLBP patients compared to HCs. Dynamic causal modelling revealed significantly enhanced effective connectivity from the right thalamus to right habenula in cLBP patients compared with HCs. RsFC of the habenula-SFC was positively correlated with pain intensities and Hamilton Depression scores in the cLBP group. RsFC of the habenula-right insula was negatively correlated with pain duration in the cLBP group. Additionally, the combination of the rsFC of the habenula-SFC, habenula-thalamus, and habenula-pons pathways could reliably distinguish cLBP patients from HCs with an accuracy of 75.9% by support vector machine, which was validated in an independent cohort (N = 68, accuracy = 68.8%, p = .001). Linear regression and random forest could also distinguish cLBP and HCs in the independent cohort (accuracy = 73.9 and 55.9%, respectively). Overall, these findings provide evidence that cLBP may be associated with abnormal rsFC and effective connectivity of the habenula, and highlight the promise of machine learning in chronic pain discrimination.

Functional disruptions of the brain network in low back pain: a graph-theoretical study.

PURPOSE: The aim of this study was to investigate alterations in the topological organization of whole-brain functional networks in patients with chronic low back pain (CLBP) and characterize the relationship of these alterations with pain characteristics. METHODS: Thirty-three CLBP patients and 34 matched healthy controls (HCs) underwent fMRI scans. A graph-theoretical approach was applied to identify brain network changes in patients suffering from chronic low back pain given its nonspecific etiology and complexity. Graph theory-based analysis was used to construct functional connectivity matrices and extract the features of small-world networks of the brain in both groups. Then, the whole-brain functional connectivity differences were characterized by network-based statistics (NBS) analysis, and the relationship between the altered brain features and clinical measures was explored. RESULTS: At the global level, patients with CLBP showed significantly decreased gamma, sigma, global efficiency, and local efficiency and increased lambda and shortest path length compared with HCs. At the regional level, there were deficits in nodal efficiency within the default mode network and salience network. NBS analysis demonstrated that decreased functional connectivity was present in the CLBP patients, mainly in the frontolimbic circuit and temporal regions. Furthermore, aspects of topological dysfunctions in CLBP were correlated with pain severity. CONCLUSION: This study highlighted the aberrant topological organization of functional brain networks in CLBP, which may shed light on the pathophysiology of CLBP and support the development of pain management approaches.

[Subcellular distribution of trace elements in wound granulation tissue of severe burn patients by inductively coupled plasma mass spectrometry].

A method for simultaneous and quantitative determination of Cr, Mn, Fe, Co, Cu, Zn, Se and Cd elements in the subcellular fractions of nuclei, mitochondria, lysosome, microsome and cytosol of wound granulation tissue of severe burn patients by octopole reaction system (ORS) inductively coupled plasma mass spectrometry (ICP-MS) was established. Using differential centrifugation, the sample is separated into different subcellular fractions. The subcellular fraction was digested by HNO3 + H2O2 with microwave digestion followed by dilution with ultrapure water then the above 8 trace elements in the solution were analyzed directly by ICP-MS. In the presented method, using ORS eliminates the polyatomic interferences caused by the matrixes. Rh as internal standard element was used to compensate matrix effect and signal drift. The detection limits of the 8 elements are in the range of 0.72-33.05 ng x L(-1), and the RSD is less than 8.4%. The results showed that the levels of some elements in subcellular fractions of wound granulation tissues were significantly different from those of normal skin tissues. ORS-ICP-MS is a useful tool for simultaneous determination of multi-elements in wound granulation tissue of severe burn patients, and could be widely used in other biological samples analysis.

A new C19-diterpenoid alkaloid in Aconitum georgei Comber.

Nine diterpenoid alkaloids were isolated from Aconitum georgei Comber belonging to the genus Aconitum in Ranunculaceae family. Their structures were determinated by using HR-ESI-MS and 1 D/2D NMR spectra as geordine (1), yunaconitine (2), chasmanine (3), crassicauline A (4), forestine (5), pseudaconine (6), 14-acetylalatisamine (7), austroconitine B (8), and talatisamine (9). Among them, compound 1 is a previously undescribed aconitine-type C19-diterpenoid alkaloid, and compounds 3, and 5-9 have not previously been isolated from this species. The results of in vitro experiments indicated that new compound 1 possesses mild anti-inflammatory activity, which inhibited the production of NO in LPS-activated RAW 264.7 cells with an inhibition ratio of 29.75% at 50 µM.

Altered effective connectivity within the cingulo-frontal-parietal cognitive attention networks in chronic low back pain: a dynamic causal modeling study.

Dysfunction of the cingulo-frontal-parietal (CFP) cognitive attention network has been associated with the pathophysiology of chronic low back pain (cLBP). However, the direction of information processing within this network remains largely unknown. We aimed to study the effective connectivity among the CFP regions in 36 cLBP patients and 36 healthy controls by dynamic causal modeling (DCM). Both the resting-state and task-related (Multi-Source Interference Task, MSIT) functional magnetic resonance imaging (fMRI) data were collected and analyzed. The relationship between the effective connectivity of the CFP regions and clinical measures was also examined. Our results suggested that cLBP had significantly altered resting-state effective connectivity of the prefrontal cortex (PFC)-to-mid-cingulate cortex (MCC) (increased) and MCC-to-left superior parietal cortex (LPC) (decreased) pathways as compared with healthy controls. MSIT-related DCM suggested that the interference task could significantly increase the effective connectivity of the right superior parietal cortex (RPC)-to-PFC and RPC-to-MCC pathways in cLBP than that in healthy controls. The control task could significantly decrease the effective connectivity of the MCC-to-LPC and MCC-to-RPC pathways in cLBP than that in healthy controls. The endogenous connectivity of the PFC-to-RPC pathway in cLBP was significantly lower than that in healthy controls. No significant correlations were found between the effective connectivity within CFP networks and pain/depression scores in patients with cLBP. In summary, our findings suggested altered effective connectivity in multiple pathways within the CFP network in both resting-state and performing attention-demanding tasks in patients with cLBP, which extends our understanding of attention dysfunction in patients with cLBP.

Altered Amygdala-prefrontal Connectivity in Chronic Nonspecific Low Back Pain: Resting-state fMRI and Dynamic Causal Modelling Study.

Chronic nonspecific low back pain (cNLBP) is a leading contributor to disease burden worldwide that is difficult to treat due to its nonspecific aetiology and complexity. The amygdala is a complex of structurally and functionally heterogeneous nuclei that serve as a key neural substrate for the interactions between pain and negative affective states. However, whether the functions of amygdalar subcomponents are differentially altered in cNLBP remains unknown. Little attention has focused on effective connectivity of the amygdala with the cortex in cNLBP. In this study, thirty-three patients with cNLBP and 33 healthy controls (HCs) were included. Resting-state functional connectivity (rsFC) and effective connectivity of the amygdala and its subregions were examined. Our results showed that the patient group exhibited significantly greater rsFC between the left amygdala and left dorsal medial prefrontal cortex (mPFC), which was negatively correlated with pain intensity ratings. Subregional analyses suggested a difference located at the superficial nuclei of the amygdala. Dynamic causal modelling revealed significantly lower effective connectivity from the left amygdala to the dorsal mPFC in patients with cNLBP than in HCs. Both groups exhibited stronger effective connectivity from the left amygdala to the right amygdala. In summary, these findings not only suggested altered rsFC of the amygdala-mPFC pathway in cNLBP but also implicated an abnormal direction of information processing between the amygdala and mPFC in these patients. Our results further highlight the involvement of the amygdala in the neuropathology of cNLBP.

Larger regional volume of the thalamus in diarrhea-predominant irritable bowel syndrome: a cross-sectional study.

As a relay center between the cerebral cortex and various subcortical brain areas, the thalamus is repeatedly associated with the dysfunction of brain-gut interaction in patients with irritable bowel syndrome (IBS). However, the regional morphological alterations of the thalamus in IBS are not well defined. We acquired structural magnetic resonance data from 34 patients with IBS and 34 demographically similar healthy subjects. Data processing was performed using FMRIB's Integrated Registration and Segmentation Tool (FIRST). Volumetric analysis and surface-based vertex analysis were both carried out to characterize the morphology of the thalamus and other subcortical structures. Our results suggested that the majority (31 cases) of the patients with IBS had diarrhea-predominant symptoms. Volumetric analysis revealed a larger normalized volume of the right thalamus and left caudate nucleus in patients with IBS than in healthy controls. Surface analysis indicated that the difference arose mainly from the laterodorsal nucleus of the right thalamus, and the body of the left caudate nucleus. In addition, patients with IBS had different hemispheric asymmetries of the thalamus (rightward) and caudate nucleus (leftward) from controls (leftward for the thalamus and rightward for the caudate nucleus). In general, our results indicated that patients with diarrhea-predominant IBS had enlarged thalamus and caudate nucleus volumes, as well as altered hemispheric asymmetries of these two structures, compared with healthy controls. The neuroimaging evidence of these structural alterations helps clarify the underlying pathophysiology of diarrhea-predominant IBS.

[Discharge and Contents of Exosome from Leukocyte-Reduced Apheresis Platelet Stored for Different Storage Time].

OBJECTIVE: To explore the effect of storage time on discharge and content of exosome from leukocyte-reduced apheresis platelets (LRA-Plt). METHODS: Exosome (EXO) from LRA-Plt were acquired by ExoQuick, and its' morphology, immunological marker and particle size distribution were detected by transmission electron microscopy (TEM), Western blotting and dynamic light scattering (DLS), respectively. The changes in particle size distribution of EXO from LRA-Plt with different storage time were detected by DLS. The changes in content of protein and RNA of EXO from LRA-Plt with different storage time were detected by Nanodrop® ND-2000. RESULTS: EXO from LRA-Plt was acquired successfully, which was characterized by cup-like shape, CD63/TSG101 enriched and Calnexin negative, and the particle size of which ranged from 30 to 200 nm. At early stored stage (stored for 1 day and 2 days), particle size of EXO from LRA-Plt was small and ranges from 30 to 40 nm. Meanwhile, the contents of protein and RNA were low. The particle size distribution, contents of protein and RNA of EXO from LRA-Plt were not significanty different ammg groups (P＞0.05). At middle-late stored stage (stored for 3, 4 and 5 days), the particle size of EXO from LRA-Plt was larger than that of early stored stage, which ranges was from 130 to 200 nm. Meanwhile, the contents of protein and RNA were higher than those of early stored stage. Particle size distribution, contents of protein and RNA of EXO from LRA-Plt stored for middle-late stage were significant higher than those of early stored stage (P＜0.05). CONCLUSION: Morphology of EXO from LRA-Plt stored for middle-late stage was different from that stored for early stored stage. Moreover, the particle size distribution, contents of protein and RNA of EXO from LRA-Plt stored for middle-late stage were higher than those of early stored stage. A large amount of protein and RNA contained in EXO from LRA-Plt may participate in the multiple functions caused by platelet transfusion.

GPNMB silencing suppresses the proliferation and metastasis of osteosarcoma cells by blocking the PI3K/Akt/mTOR signaling pathway.

Glycoprotein non­metastatic melanoma protein B (GPNMB) is a glycoprotein that is highly expressed in various types of cancer, including osteosarcoma. However, its cellular functions and related mechanisms in osteosarcoma remain unclear. In the present study, a higher GPNMB mRNA level was observed in osteosarcoma tissues, than in adjacent non­cancerous tissues. In addition, upregulation of the GPNMB mRNA and protein level was detected in the osteosarcoma cells SaOS2, 143B, MG63 and U2OS using western blot analysis and qPCR. Following transfection with GPNMB siRNA, the proliferation, migration and invasion of MG63 and U2OS cells were assessed using MTT and Transwell assays. The knockdown of GPNMB markedly inhibited the proliferation and metastasis of MG63 and U2OS cells. GPNMB silencing inhibited the activation of PI3K/Akt/mTOR signaling in MG63 and U2OS cells. PI3K/AKT activator insulin­like growth factor­1 (IGF­1) significantly activated the PI3K/Akt/mTOR signaling and reversed the suppressive effects of GPNMB silencing. IGF­1 counteracted the inhibitory effects of GPNMB silencing on the proliferation and metastasis of the MG63 and U2OS cells. In conclusion, we provided evidence that GPNMB silencing regulated the proliferation and metastasis of osteosarcoma cells by suppressing the PI3K/Akt/mTOR signaling pathway. Thus, GPNMB may be a potential therapeutic target for osteosarcoma treatment.

[Brain gray matter abnormalities revealed by voxel-based morphometry in patients with chronic low back pain].

OBJECTIVE: To explore the morphometric abnormalities of brain gray matter (GM) in patients with chronic low back pain (CLBP). METHODS: Thirty patients with CLBP and 30 healthy individuals were enrolled and examined with a 3.0 T magnetic resonance (MR) scanner. High-resolution T1 structural MR data were acquired and data analysis was performed using voxel-based morphometry (VBM) in FMRIB Software Library. The morphological differences were compared between the two groups. RESULTS: s Compared with the healthy control subjects, patients with CLBP showed decreased GM volumes in several brain cortical areas including the bilateral superior frontal gyrus, right frontal pole, left insular cortex, left middle and left inferior temporal gyrus (P<0.05, after TFCE correction). Increased GM volumes were found in the patients in the subcortical structures including the left thalamus, bilateral putamen, bilateral nucleus accumben and right caudate nucleus (P<0.05, after TFCE correction). CONCLUSION: Patients with CLBP have different patterns of GM abnormalities in different brain regions, characterized by reduced GM volume in cerebral cortical regions and increased GM volume in the subcortical nuclei. Such changes might be associated with the maladaptation of the brain in chronic pain state.

Smaller Amygdala Volumes in Patients With Chronic Low Back Pain Compared With Healthy Control Individuals.

UNLABELLED: Although preclinical and clinical data strongly support an association between the amygdala and chronic pain by the presence of mood and cognitive disturbances in affected individuals, little attention has been paid to morphometric measurement of the structure in patients with chronic low back pain (CLBP). In the present study, magnetic resonance volumetric and surface analysis, using FMRIB's integrated registration and segmentation tool (FIRST), were performed to compare structural magnetic resonance imaging data obtained from 33 patients with CLBP with those obtained from 33 demographically similar healthy control individuals. Our results indicated that the normalized volumes of the left and right amygdala were significantly smaller in the CLBP group than in the control group. Detailed surface analyses further localized these differences. The degree of volume reduction was different between the left and right amygdala, with a greater involvement of the left side. Both groups exhibited similar significant hemispheric asymmetry for the amygdala (left > right). Similar asymmetry was suggested in the subgroup of 24 unmedicated patients. No significant correlations were found between amygdala volumes and pain characteristics or depressive symptoms. Our study provides in vivo imaging evidence of abnormal morphology of the amygdala in patients with CLBP using a fully automated segmentation method. PERSPECTIVE: Our study found that patients with CLBP had statistically significantly smaller normalized volumes of the bilateral amygdala, compared with healthy control individuals, with a greater involvement of the left side. These results may help to characterize the impaired affective-cognitive dimension in patients with chronic pain.