Melatonin Suppresses Neuropathic Pain via MT2-Dependent and -Independent Pathways in Dorsal Root Ganglia Neurons of Mice.

Melatonin (Mel) and its receptors (MT1 and MT2) have a well-documented efficacy in treating different pain conditions. However, the anti-nociceptive effects of Mel and Mel receptors in neuropathic pain (NP) are poorly understood. To elucidate this process, pain behaviors were measured in a dorsal root ganglia (DRG)-friendly sciatic nerve cuffing model. We detected up-regulation of MT2 expression in the DRGs of cuff-implanted mice and its activation by the agonist 8-M-PDOT (8MP). Also, Mel attenuated the mechanical and thermal allodynia induced by cuff implantation. Immunohistochemical analysis demonstrated the expression of MT2 in the DRG neurons, while MT1 was expressed in the satellite cells. In cultured primary neurons, microarray analysis and gene knockdown experiments demonstrated that MT2 activation by 8MP or Mel suppressed calcium signaling pathways via MAPK1, which were blocked by RAR-related orphan receptor alpha (RORα) activation with a high dose of Mel. Furthermore, expression of nitric oxide synthase 1 (NOS1) was down-regulated upon Mel treatment regardless of MT2 or RORα. Application of Mel or 8MP in cuff-implanted models inhibited the activation of peptidergic neurons and neuro-inflammation in the DRGs by down-regulating c-fos, calcitonin gene-related peptide [CGRP], and tumor necrosis factor-1α [TNF-1α] and interleukin-1ß [IL-1ß]. Addition of the MT2 antagonist luzindole blocked the effects of 8MP but not those of Mel. In conclusion, only MT2 was expressed in the DRG neurons and up-regulated upon cuff implantation. The analgesic effects of Mel in cuff-implanted mice were closely associated with both MT2-dependent (MAPK-calcium channels) and MT2-independent (NOS1) pathways in the DRG.

Intracranial lesion as onset symptom in a patient with early undifferentiated connective tissue disease: a case report.

BACKGROUND: Undifferentiated connective tissue disease (UCTD) is widely considered to be a distinct clinical entity, and now divided into two subgroups: stable UCTD and early UCTD. The most frequent onset symptoms of UCTD include arthralgias, arthritis, Raynaud's phenomenon, mucocutaneous involvement, and sicca symptoms. However, Neurologic involvement is rare, and intracranial lesion as onset symptom in a patient with early UCTD has not yet been reported. CASE PRESENTATION: A 51-year-old Chinese female experienced progressive left leg weakness for 14 days before hospitalizing in our department. The lesion on right parietal lobe was initially detected by brain magnetic resonance imaging. Although the patient declined a cerebral biopsy, the possibility of stroke, cerebral venous sinus thrombosis, NMOSD, MS, autoimmune encephalitis, intracranial infections, and malignant tumors as cause of the lesion was excluded by intracranial angiogram, CSF study, MRI enhancement and MRS examination. Moreover, immunologic studies showed high titer of antinuclear antibody, increased erythrocyte sedimentation rate and C-reactive protein. These results led to a diagnosis of early UCTD with central nerve system (CNS) involvement. After low dose corticosteroid and azathioprine therapy, the patient's symptoms, abnormalities in immunologic tests and cerebral radiologic examinations were all greatly improved within a short duration. CONCLUSIONS: This is the first report of intracranial lesion as onset symptom in a patient with early UCTD. Our case suggested that central nerve system (CNS) involvement could be the onset symptom in early UCTD, and should be recognized quickly with exclusion of other causative factors in the differential diagnosis. Prompt and adequate treatment with low-dose steroid and immunosuppressive drugs could improve the prognosis of both early UCTD and CNS involvement.

Increased Circulating T Follicular Helper Cells Are Inhibited by Rituximab in Neuromyelitis Optica Spectrum Disorder.

Neuromyelitis optica spectrum disorder (NMOSD) is a severe autoimmune disease of the central nervous system. The existence of autoantibody targeting aquaporin-4 (AQP4-Ab) indicates the involvement of humoral immunity in the pathogenesis of this disease. Rituximab (RTX), a monoclonal antibody against CD20, has been used to treat NMOSD by depleting circulating B cells and overall satisfactory outcome has been achieved. Although T follicular helper cells have been proved to regulate B cell activation and antibody production, the role of these cells in NMOSD and the impact of RTX treatment on these cells remain less understood. In this study, we found that frequencies of circulating T follicular helper (cTfh) cells and B cells together with the related cytokines, IL-21 and IL-6, were closely correlated with disease activity of NMOSD. Furthermore, B cell depletion with RTX treatment inhibited the expansion of cTfh cells, and these effects were achieved through eliminating IL-6-producing B cells and blocking the direct contact between cTfh cells and B cells. These findings imply the complicated cross talk between cTfh cells and B cells and may provide a novel therapeutic target for NMOSD.

Diffusion tensor imaging characterization of occult brain damage in relapsing neuromyelitis optica using 3.0T magnetic resonance imaging techniques.

Studies of relapsing neuromyelitis optica (RNMO) using advanced MRI techniques are limited compared with those done on multiple sclerosis (MS). The present study used diffusion tensor imaging (DTI) to investigate whether occult brain damage exists in RNMO patients. DTI scans using a 3.0T MRI scanner were performed in 24 clinically confirmed RNMO patients whose conventional brain MRI results were normal, and also in 24 age- and sex-matched healthy control subjects. DTI data were processed to generate fractional anisotropy (FA) and mean diffusivity (MD) maps, and region of interest (ROI) analyses were performed to obtain these parameters in white matter (including medulla oblongata, cerebral peduncle, optic radiation, genu of corpus callosum, splenium of corpus callosum, and internal capsule) and gray matter (including thalamus and putamen). Regional measures from patients at stable and acute phases were compared with healthy controls. Both acute and stable NMO patients had a higher average FA in ROIs of the thalamus and putamen. Acute NMO patients had significantly higher average MDs than controls in the genu of corpus callosum and optic radiation, and significantly lower average MDs in the medulla oblongata. Stable NMO patients had increased MDs in the genu of corpus callosum and optic radiation, but lower MDs in the medulla oblongata, internal capsule and thalamus. The DTI findings confirm the presence of occult tissue damage in normal-appearance white and gray matter, especially deep gray matter, in RNMO patients. This study adds further to the evidence that DTI is suitable as a tool for characterizing subtle brain tissue damage.