Correlation analysis between plasma fibrinogen and nerve electrophysiological changes in type 2 diabetic peripheral neuropathy.

INTRODUCTION: The aim of the study was to investigate the pathogenesis of diabetic peripheral neuropathy (DPN) and the value of fibrinogen (FIB) in the early diagnosis of DPN. MATERIAL AND METHODS: A total of 121 patients with type 2 diabetes mellitus (T2DM) and DPN hospitalized in the Endocrinology Department of the 923 Hospital of the People's Liberation Army of China were randomly selected between May and October 2020 and divided into a T2DM asymptomatic (no peripheral neuropathy-related symptoms) group (66 cases) and a T2DM symptomatic group (55 cases) according to the presence or absence of clinical neurological symptoms and signs. Forty healthy volunteers were selected as a normal control group. In addition to plasma FIB and nerve electrophysiological tests, all included subjects were electrophysiologically tested for nerve conduction velocity (NCV), terminal motor latency (DML), sensory nerve action potential (SNAP) amplitude, and compound muscle action potential (CMAP) amplitude. RESULTS: Compared with the control group, NCV was slowed down in T2DM patients, DML was prolonged, and the amplitude of CMAP and SNAP were decreased. Compared with asymptomatic T2DM patients, symptomatic patients had slower NCV, longer DML, lower CMAP amplitude of median nerve, ulnar nerve and tibial nerve, and significantly lower SNAP amplitude of median nerve and ulnar nerve. CMAP amplitudes were decreased, and median and ulnar nerve SNAP amplitudes were also significantly decreased ( p < 0.05). The plasma FIB concentration of asymptomatic patients with T2DM was higher than that of the control group, and the plasma FIB concentration of symptomatic patients with T2DM was higher than that of asymptomatic patients with T2DM ( p < 0.01). The NCV and DML of asymptomatic patients with T2DM slowed down and prolonged as the FIB level increased; the NCV of T2DM symptomatic patients also slowed down as FIB increased, and median and ulnar nerve DML increased as FIB increased. There was no correlation between NCV and DML and the plasma FIB level in the control group. SNAP amplitudes of symptomatic and asymptomatic patients with T2DM decreased as plasma FIB increased, while CMAP amplitudes of the tibial nerve and the T2DM symptomatic ulnar nerve decreased as FIB increased in the control group. CONCLUSIONS: FIB may be a contributing factor for diabetic neuropathy and could be used as an indicator in the early screening and diagnosis of peripheral neuropathy in patients with T2DM.

Role of Fibrinogen in Type-2 Diabetes Mellitus with Diabetic Neuropathy and its Preliminary Mechanism.

INTRODUCTION: Diabetic peripheral neuropathy (DN) is the most common complication of type 2 diabetes mellitus (T2DM). OBJECTIVE: This study aimed to explore the role of fibrinogen (FIB) in T2DM neuropathy and its preliminary mechanism. METHODS: Ten male Sprague-Dawley rats were divided into a normal control group (NC group) and a T2DM neuropathy model group (DN group). The DN group was given a high-energy diet and streptozotocin, while the NC group was given a normal diet and a citric acid buffer. The expression levels of related proteins were analysed. RESULTS: Electrophysiology: Compared with the NC group, the conduction latency of the somatosensory-evoked potential and nerve conduction velocity was prolonged in the DN group, while the motor nerve action potential was decreased. As seen under a light microscope, the peripheral nerve fibres in the DN group were swollen, and the nerve fibres in the posterior funiculus of the spinal cord were loose or missing. Moreover, as seen under an electron microscope, the peripheral nerve demyelination of the DN group was severe, with microvascular blood coagulation, luminal stenosis, and collapse. Compared with the NC group, in the DN group, the expression of FIB was positively correlated with the expression of both ionised calcium-binding adaptor molecule-1 and glial fibrillary acidic protein. Compared with the NC group, in the DN group, the expression of platelet/endothelial cell adhesion molecule-1 and B-cell lymphoma 2 was negatively correlated. CONCLUSION: The increased concentration of FIB may be the cause of neuropathy, and its mechanism may be related to its promotion of inflammatory response, blood coagulation, and vascular stenosis.

Polysaccharides from Laminaria japonica protect memory abilities and neurogenesis in mice after cranial irradiation through ameliorating neuroinflammation and collagen IV degradation.

BACKGROUND: Radiation-induced brain injury (RIBI) is one of the most common long-term complications for patients with malignant brain tumors after radiotherapy. At present, there is no effective treatment for RIBI. Recent studies have also confirmed that polysaccharides from laminaria japonica (LJP) display potential neuroprotective function. However, its mechanisms of neuroprotection remain unclear. AIM: In this study, we aimed to explore the effect and underlying mechanism of LJP on neurogenesis in radiation-induced brain injury mice. METHODS: SPF two-month-old male mice were randomly divided into control group (Con), LJP treatment group (LJP), irradiation group (IR), and irradiation with LJP treatment group (IR + LJP). LJP (40 mg/kg/day) was intraperitoneally injected at one day before radiation for seven consecutive days (once daily). The mice were exposed to 10 Gy × 2 fractionated doses, once every other day, with a total dose of 20 Gy. Changes in cognitive function of mice following radiation were evaluated by the Morris water maze test. Furthermore, body weight and general status of mice were measured throughout the experiment. Immunohistochemical staining for neural proliferating cells (Ki67+ cells) and immature neurons (DCX + cells) was utilized to assay changes of neurogenesis in hippocampus. Microglial activation and collagen IV deposition within the neurogenic microenvironment were observed respectively by immunohistochemical staining for Iba-1 and Collagen IV in the hippocampus. Levels of pro-inflammatory cytokines (TNF-α and IL-1ß) in the hippocampus were detected by ELISA kits post-radiation. RESULTS: Morris water maze test showed that LJP therapy markedly reduced the escape latency and increased the times of crossing platform and percent time of the target quadrant in the radiated mice. In addition, the decrease of the neural proliferating cells (Ki67+ cells) and immature neurons (DCX + cells) in the hippocampus of mice following irradiation was significantly mitigated by the LJP treatment, suggesting that LJP could prevent from neurogenesis damage after irradiation. LJP injection significantly attenuated degradation of collagen IV, activation of microglia, and increase of pro-inflammatory cytokines (TNF-α and IL-1ß) levels in the neurogenic microenvironment of the hippocampus after radiation. CONCLUSION: These findings suggest that LJP early treatment may mitigate radiation-induced cognitive impairments and that its mechanism may relate to its protection of neurogenesis by alleviating neuroinflammation and collagen IV degradation within the neurogenic microenvironment.