Purpose To determine the role of diffusion tensor imaging (DTI) metrics as biomarkers for the therapeutic effects of mesenchymal stem cells (MSCs) in acute peripheral nerve injury. Materials and Methods Forty‐four adult rats received subepineurial microinjection of MSCs (n = 22) or phosphate buffered saline (PBS, n = 22) 1 week after the sciatic nerve trunk crush injury. Sequential fat‐suppressed T2‐weighted imaging, T2 measurement, DTI and sciatic nerve functional assessment were performed at a 3.0 Tesla MR unit over an 8‐week follow‐up, with histological assessments performed at regular intervals. The sciatic nerve function index, T2 value, and DTI metrics, including fractional anisotropy (FA), axial diffusivity, radial diffusivity (RD), and mean diffusivity values of the distal stumps of crushed nerves were measured and compared between the two groups. Results Nerves treated with MSCs showed better functional recovery and exhibited more pronounced nerve regeneration compared with nerves treated with PBS. T2 values in nerves treated with MSCs or PBS showed a similar change pattern ( P = 0.174), while FA and RD values in nerves treated with MSCs showed more rapid return (one week earlier) to baseline level than nerves treated with PBS ( P = 0.045; 0.035). Nerves treated with MSCs had higher FA and lower RD values than nerves treated with PBS during the period from 2 to 3 weeks after surgery ( P ≤ 0.0001, 0.004; P = 0.004, 0.006). Conclusion FA and RD values derived from DTI might be used as sensitive biomarkers for detecting the therapeutic effect of stem cells in acute peripheral nerve crush injuries. Level of Evidence: 2 J. Magn. Reson. Imaging 2017;45:855–862.
Tinnitus is a prevalent hearing disorder, which could have a devastating impact on a patient's life. Functional studies have revealed connectivity pattern changes in the tinnitus brains that suggested a change of network dynamics as well as topological organization. However, no studies have yet provided evidence for the topological network changes in the gray matter. In this research, we aim to use the graph-theoretical approach to investigate the changes of topology in the tinnitus brain using structural MRI data, which could provide insights into the underlying anatomical basis for the neural mechanism in generating phantom sounds.We collected 3D MRI images on 46 bilateral tinnitus patients and 46 age and gender-matched healthy controls. Brain networks were constructed with correlation matrices of the cortical thickness and subcortical volumes of 80 cortical/subcortical regions of interests. Global network properties were analyzed using local and global efficiency, clustering coefficient, and small-world coefficient, and regional network properties were evaluated using the betweenness coefficient for hub connectivity, and interregional correlations for edge properties. Between-group differences in cortical thickness and subcortical volumes were assessed using independent sample t-tests, and local efficiency, global efficiency, clustering coefficient, sigma, and interregional correlation were compared using non-parametric permutation tests.Tinnitus was found to have increased global efficiency, local efficiency, and cluster coefficient, indicating generally heightened connectivity of the network. The small-world coefficient remained normal for tinnitus, indicating intact small-worldness. Betweenness centrality analysis showed that hubs in the amygdala and parahippocampus were only found for tinnitus but not controls. In contrast, hubs in the auditory cortex, insula, and thalamus were only found for controls but not tinnitus. Interregional correlation analysis further found in tinnitus enhanced connectivity between the auditory cortex and prefrontal lobe, and decreased connectivity of the insula with anterior cingulate gyrus and parahippocampus.These findings provided the first morphological evidence of altered topological organization of the brain networks in tinnitus. These alterations suggest that heightened efficiency of the brain network and altered auditory-limbic connection for tinnitus, which could be developed in compensation for the auditory deafferentation, leading to overcompensation and, ultimately, an emotional and cognitive burden.
Objective: This research was designed to probe into the effects of Dapagliflozin on renal interstitial fibrosis in diabetic rats through Smad3, TIMP1 and MMP24 pathway. Methods: Rats were bought to establish models, and then intervened by Dapagliflozin. Human mesangial cell lines (HMCs) stimulated by high glucose were purchased, and the Smad3, TIMP1 and MMP24 levels in rats after modeling and Dapagliflozin intervention were detected. The Smad3, TIMP1 and MMP24 protein expression in kidney tissue was examined after the rats were killed, and the expression in an intervention group (IG) and a blank group (BG) were analyzed. The cells were divided into three groups: Dapagliflozin intervention (Group 1), TGF-P1/Smad3 pathway inhibitor SIS3 intervention (Group 2) and no intervention (Group 3). The TIMP1 and MMP24 levels were assessed. Results: The Smad3 and MMP24 levels in group A were higher than those in other two groups (p < 0.05), while those of TIMP1 were lower (p < 0.05). Compared with pre-intervention, the Smad3 and MMP24 levels in groups A and B decreased (p < 0.05), while those of TIMP1 increased (p < 0.05). The Smad3 and MMP24 protein levels in groups A and B were higher than those in other two groups (p < 0.05), while those of TIMP1 was lower (p < 0.05). Compared with the BG, the Smad3 and MMP24 expression in the IG was lower (p < 0.05) and that of TIMP1 was higher (p < 0.05). The TIMP1 expression in Group 3 was lower (p < 0.05) and that of MMP24 was higher than those in Groups 1 and 2 (p < 0.05). Conclusion: Dapagliflozin can treat diabetic renal interstitial fibrosis by inhibiting TGF-P1/Smad3 signaling pathway, decreasing MMP24 and increasing TIMP1.
ABSTRACT Introduction : Macrophage recruitment is critical for nerve regeneration after an injury. The aim of this study was to investigate whether ultrasmall superparamagnetic iron oxide (USPIO) nanoparticle‐based MRI could be used to monitor the enhanced macrophage recruitment by Toll‐like receptor 4 (TLR4) activation in nerve injury. Methods : Rats received intraperitoneal injections of either lipopolysaccharide (LPS) or phosphate buffered saline (PBS) or no injection (controls) after a sciatic nerve crush injury. After intravenous injection of the USPIOs (LPS and PBS groups) or PBS (control group), MRI was performed and correlated with histological findings. Results : LPS group showed more remarkable hypointense signals on T2*‐weighted imaging and lower T2 values in the crushed nerves than PBS group. The hypointense signal areas were associated with an enhanced recruitment of iron‐loaded macrophages to the injured nerves. Discussion : USPIO‐enhanced MRI can be used to monitor the enhanced macrophage recruitment by means of TLR4 signal pathway activation in nerve injury. Muscle Nerve 58 : 123–132, 2018
To investigate the changes of serum miR-202-3p level and its correlation with prognosis in patients with acute kidney injury (AKI) induced by sepsis. From April 2017 to January 2019, 66 patients with AKI induced by sepsis in our hospital and 70 healthy people in the same period were selected as the research objects. The levels of miR-202-3p, BUN and Cr in serum were tested. Subsequently, cell experiments were carried out to verify the effects of the decrease of miR-202-3p level on BUN, Cr and cell growth and apoptosis. The risk factors were analysed. Compared with healthy volunteers, patients with AKI induced by sepsis had higher levels of miR-202-3p, BUN and Cr in serum. When miR-202-3p level was knocked down, the levels of BUN and Cr were declined, cell growth was improved and apoptosis rate was decreased. The risk factors were analysed, and the results revealed that miR-202-3p, BUN and Cr were independent risk factors for poor prognosis in patients with AKI induced by sepsis. The level of miR-202-3p is elevated in patients with AKI induced by sepsis, which may be a potential biomarker for diagnosis and prognosis of patients with AKI induced by sepsis.
ABSTRACT Introduction The immune system plays a pivotal role in nerve injury. The aim of this study was to determine the role of multiparametric magnetic resonance imaging (MRI) in evaluation of the synergic effect of immunomodulation on nerve regeneration in neurotmesis. Methods Rats with sciatic nerve neurotmesis and surgical repair underwent serial multiparametric MR examinations over an 8‐week period after subepineurial microinjection of lipopolysaccharide (LPS) and subsequent subcutaneous injection of FK506 or subepineurial microinjection of LPS or phosphate‐buffered saline (PBS) alone. Results Nerves treated with immunomodulation showed more prominent regeneration than those treated with LPS or PBS alone and more rapid restoration toward normal T2, fractional anisotropy (FA), and radial diffusivity (RD) values than nerves injected with LPS or PBS. Discussion Nerves treated with immunomodulation exert synergic beneficial effects on nerve regeneration that can be predicted by T2 measurements and FA and RD values. Muscle Nerve 57 : E38–E45, 2018
Objective
To investigate the value of magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) in the diagnosis of autoimmune pancreatitis (AIP).
Methods
Clinical data of 11 patients pathologically diagnosed with AIP in Sun Yat-sen Memorial Hospital, Sun Yat-sen University from January 2013 to June 2014 were analyzed retrospectively. There were 7 males and 4 females with a mean age of (54±15) years old. The informed consents of all patients were obtained and local ethical committee approval had been received. Apparent diffusion coefficient (ADC) of the pancreatic lesions was measured by MRI scan, multiphase dynamic enhanced scan and DWI. The imaging features of AIP by MRI and DWI were observed.
Results
The AIP lesions displayed iso- or slightly hypo-intense signal on T1WI and slightly hyper-intense signal on T2WI by MRI and continuous gradual enhancement by multiphase dynamic enhanced scan. The average ADC of the lesions by DWI was (1.09±0.09)×10-3 mm2/s and the pancreatic lesions displayed high signal. Diffusely swelling pancreas with plump shape, sausage-like appearance was observed in 7 cases. Local mass were observed at the pancreatic head in 3 cases. Mass in the pancreatic body and tail was observed in 1 case. Capsule-like ring-like shadow was observed around the pancreas in 6 cases by MRI and iso- or slightly hypo-intense signal on T1WI and slightly lower- or hyper-intense signal on T2WI were observed. No enhancement or hypo-enhancement was observed in arterial phase by multiphase dynamic enhanced scan. Delayed enhancement was observed in delayed phase. The enhancement degree was mildly lower than that of pancreatic parenchyma. Multiple enlarged lymph nodes were observed around the pancreas and at the retroperitoneum in 4 cases.
Conclusions
MRI is useful for the diagnosis of AIP. The dynamic enhanced scan and DWI findings can be used as the direct images for diagnosing AIP and have a high clinical reference value.
Key words:
Pancreatitis, chronic; Magnetic resonance imaging; Contrast media; Diffusion-weighted imaging
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