Donghui Shen

The roles of macrophages and microglia in multiple sclerosis and experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is an autoimmune and neurodegenerative disorder characterized by chronic inflammation, demyelination, as well as axonal and neuronal loss in the central nervous system (CNS). Macrophages and microglia are important components of the innate immune system. They participate in the primary response to microorganisms and play a role in inflammatory responses, homeostasis, and tissue regeneration. In the initial phase of MS and experimental autoimmune encephalomyelitis (EAE), an animal model of MS, macrophages from peripheral tissues infiltrate into the CNS and, together with residential microglia, contribute to the pathogenesis of MS. In the early stages, microglia and macrophages are expressed as the M1 phenotype, which can release proinflammatory cytokines, leading to tissue damage in the CNS. However, in the later stage, the M2 phenotype, which is the phenotype that is associated with resolving inflammation and tissue repair, becomes predominant in the CNS. Therefore, it is hypothesized that the M1/M2 phenotype balance plays an important role in disease progression and that the transition from the proinflammatory M1 phenotype to the regulatory or anti-inflammatory M2 phenotype can lead to restoration of homeostasis and improved functional outcomes. This review of recent literature focuses on the discussion of the M1/M2 phenotypes of microglia and macrophages as well as their relevance in the pathophysiology and treatment of MS and EAE. Furthermore, the possibility of directing the polarization of microglia and macrophages toward the M2 phenotype as a therapeutic and preventative strategy for MS is discussed.

Distinct Clinical Characteristics of Pediatric Guillain-Barré Syndrome: A Comparative Study between Children and Adults in Northeast China

Objective Clinical characteristics of pediatric Guillain-Barré syndrome (GBS) have been extensively studied whereas scarcely been compared with those of adult GBS. Herein we compared the clinical features of GBS between pediatric and adult patients. Methods We retrospectively collected the clinical data of 750 patients with GBS (541 adults and 209 children), and compared the clinical characteristics between children and adults. Results Pain was a more frequent complaint in children (17.2% vs 9.6%, p < 0.01), who were also found with shorter interval from disease onset to nadir (6.3d vs 7.3d, p < 0.01) and higher incidence of bulbar dysfunction (22.0% vs 14.8%, p < 0.05). The disease severity in children was comparable with adults. In addition, a higher incidence of pediatric GBS was found in summer, especially in July and August (both p < 0.01). However, the incidence of antecedent infections of different seasons in adult and pediatric patients was comparable (p > 0.05). The clinical features of acute motor axonal neuropathy (AMAN) and acute inflammatory demyelinating polyneuropathy (AIDP) in children were overall comparable with adult ones (p > 0.05). Similar to adults, bulbar dysfunction (odds ratio [OR]: 4.621, 95% confidence interval [CI]: 1.240–17.218, p < 0.05) and lower nadir Medical Research Council (MRC) sum score (OR: 0.897, 95% CI: 0.855–0.941, p < 0.01) were also risk factors for mechanical ventilation in children. However, distinct from adult ones, autonomic dysfunction was significantly higher in mechanically ventilated childhood GBS (39.1% vs 8.8%, p < 0.01), which also served as a predictor for mechanical ventilation in pediatric GBS (OR: 70.415, 95% CI: 9.265–535.158, p < 0.01). As to the efficacy of intravenous immunoglobulin, insignificant difference was identified between children and adults. Conclusion The clinical features of pediatric GBS differ from those of adults. Autonomic dysfunction is an independent risk factor for mechanical ventilation in pediatric patients.

More Severe Manifestations and Poorer Short-Term Prognosis of Ganglioside-Associated Guillain-Barré Syndrome in Northeast China

Ganglioside as a neurotrophic drug has been hitherto widely used in China, although Guillain-Barré syndrome (GBS) following intravenous ganglioside treatment was reported in Europe several decades ago. We identified 7 patients who developed GBS after intravenous use of gangliosides (ganglioside+ group) and compared their clinical data with those of 77 non-ganglioside-associated GBS patients (ganglioside− group) in 2013, aiming at gaining the distinct features of ganglioside-associated GBS. Although the mean age, protein levels in cerebrospinal fluid (CSF) and frequency of cranial nerve involvement were similar between the two groups, the Hughes Functional Grading Scale (HFGS) score and the Medical Research Council (MRC) sum score at nadir significantly differed (4.9±0.4 vs 3.6±1.0; 7.7±5.5 vs 36.9±14.5, both p<0.001), indicating a higher disease severity of ganglioside-associated GBS. A higher ratio of patients with ganglioside-associated GBS required mechanical ventilation (85.7% vs 15.6%, p<0.01). The short-term prognosis of ganglioside-associated GBS, as measured by the HFGS score and the MRC sum score at discharge, was poorer (4.3±0.5 vs 2.8±1.1; 17.3±12.9 vs 46.0±13.9, both p<0.001). All the patients in the ganglioside+ group presented an axonal form of GBS, namely acute motor axonal neuropathy (AMAN). When compared with the AMAN patients in the ganglioside− group, more severe functional deficits at nadir and poorer recovery after standard treatment were still prominent in ganglioside-associated GBS. Anti-GM1 and anti-GT1a antibodies were detectable in patients with AMAN while not in patients with the demyelinating subtype of GBS. The concentrations of these antibodies in patients with AMAN were insignificantly different between the ganglioside+ and ganglioside− groups. In sum, ganglioside-associated GBS may be a devastating side effect of intravenous use of gangliosides, which usually manifests a more severe clinical course and poorer outcome.

Short-Term Prognosis of Mechanically Ventilated Patients With Guillain–Barré Syndrome Is Worsened by Corticosteroids as an Add-On Therapy

AbstractIntravenous immunoglobulin (IVIg) has been proven most effective in treating Guillain–Barré syndrome (GBS). Corticosteroids as an add-on therapy have been prescribed in severe GBS cases. However, the efficacy of intravenous corticosteroids combined with IVIg in dealing with severe GBS remains unclear. We explored the therapeutic effects of different therapeutic regimens on the short-term prognosis of GBS patients, especially the severe cases.We retrospectively analyzed the clinical data of 527 adult patients with GBS who were prescribed to different treatments from 2003 to 2014. The therapeutic effect of a treatment was evaluated by the improvement of Hughes Functional Grading Scale (HFGS) and Medical Research Council (MRC) sum score.With comparable incidence of infectious complications (P > 0.05), more mechanically ventilated patients were found improvement after IVIg treatment than combination IVIg with intravenous corticosteroids (MRC: 97% vs. 72.4%, P < 0.05; HFGS: 97% vs. 72.4%, P < 0.05). As to bedridden patients without mechanical ventilation, incidence of infectious complications (P > 0.05) and ratio of patients who were improved after IVIg were insignificantly different from the combination therapy (MRC: 89.6% vs. 86.5%; HFGS: 69.6% vs. 61.5%; both P > 0.05), even if the intravenous corticosteroids were initiated within 7 days after onset (P > 0.05). In addition, supportive treatment was sufficient for patients who were able to walk with help (HFGS = 3) and mildly affected (HFGS < 3) when compared with IVIg and intravenous corticosteroids.IVIg is sufficient to GBS patients who are unable to walk (HFGS > 3), while corticosteroids are detrimental for short-term prognosis in mechanically ventilated patients when used in combination with IVIg. Further prospective and randomized studies are warranted to validate this finding.

Roles of macrophage migration inhibitory factor in Guillain-Barré syndrome and experimental autoimmune neuritis: beneficial or harmful?

ABSTRACT Introduction: Macrophage migration inhibitory factor (MIF) plays an important role in the pathogenesis of Guillain-Barré syndrome (GBS) and its animal model experimental autoimmune neuritis (EAN), which may offer an opportunity for the development of the novel therapeutic strategies for GBS. Areas covered: ‘macrophage migration inhibitory factor’ and ‘Guillain-Barré syndrome’ were used as keywords to search for related publications on Pub-Med, National Center for Biotechnology Information (NCBI), USA. MIF is involved in the etiology of various inflammatory and autoimmune disorders. However, the roles of MIF in GBS and EAN have not been summarized in the publications we identified. Therefore, in this review, we described and analyzed the major roles of MIF in GBS/EAN. Primarily, this molecule aggravates the inflammatory responses in this disorder. However, multiple studies indicated a protective role of MIF in GBS. The potential of MIF as a therapeutic target in GBS has been recently demonstrated in experimental and clinical studies, although clinical trials have been unavailable to date. Expert opinion: MIF plays a critical role in the initiation and progression of GBS and EAN, and it may represent a potential therapeutic target for GBS.

The clinical characteristics and short-term prognosis in elderly patients with Guillain–Barré syndrome

Abstract To investigate the clinical characteristics and short-term prognosis of elderly patients with Guillain–Barré syndrome (GBS). We retrospectively analyzed the clinical data of adult GBS. According to the age, the enrolled subjects were divided into 2 groups, that is, patients ≥60 years (elderly group) and those aged 18 to 59 years (nonelderly group). The clinical characteristics and short-term prognosis of the patients in the 2 groups were compared. In total, 535 patients were enrolled. There were 67 patients fell into the elderly group with a mean age of 69 years old; while 468 patients fell into the nonelderly group with a mean age of 39 years old. We found that the elderly patients had significantly lower incidence of antecedent infections (49.3% vs 66.2%, P < 0.01). The time from onset to admission (5 vs 4 days, P < 0.05) and time from onset to nadir (7 vs 6 days, P < 0.05) were significantly longer in the elderly patients. It was noteworthy that more elderly patients were found with lymphocytopenia (55.4% vs 37.3%, P < 0.01), hyponatremia (25.0% vs 10.2%, P < 0.01), hypoalbuminemia (9.0% vs 2.6%, P < 0.05), and hyperglycemia (34.3% vs 15.2%, P < 0.01). Importantly, the elderly patients had longer duration of hospitalization (17 vs 14 days, P < 0.05), higher incidence of pneumonia (29.9% vs 18.8%, P < 0.05), and poorer short-term prognosis (58.2% vs 42.7%, P < 0.05). In patients with severe GBS, no significant differences were observed in disease severity, treatment modality, incidence of pneumonia, and duration of hospitalization between the 2 groups. However, more patients in the elderly group showed poor short-term prognosis (84.1% vs 63.8%, P < 0.01). Further, old age (≥60 years) (OR = 2.906, 95% CI: 1.174–7.194, P < 0.05) and lower Medical Research Council (MRC) score at nadir (OR = 0.948, 95% CI: 0.927–0.969, P < 0.01) were risk factors for poor short-term prognosis in severe GBS patients. The clinical characteristics and short-term prognosis of elderly patients with GBS are distinct from nonelderly adults. Old age (≥60 years) and lower nadir MRC score serve as predictor for poor short-term prognosis in severe GBS patients.

Role of Inflammasomes in Neuroimmune and Neurodegenerative Diseases: A Systematic Review

Inflammasomes are multiprotein complexes that can sense pathogen-associated molecular patterns and damage-associated molecular signals. They are involved in the initiation and development of inflammation via activation of IL-1β and IL-18. Many recent studies suggest a strong correlation between inflammasomes and neurological diseases, such as multiple sclerosis (MS), Alzheimers disease (AD), and Parkinsons disease (PD). Several components of inflammasomes, such as nucleotide-binding oligomerization domain- (NOD-) like receptor, absent in melanoma 2- (AIM2-) like receptors (ALRs), apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), and caspase-1, as well as the upstream factors and downstream effectors, are associated with the initiation and development of MS and its animal model, experimental autoimmune encephalomyelitis. Additionally, inflammasomes affect the efficacy of interferon-β therapy in patients with MS. Finally, the strong association of inflammasomes with AD and PD needs to be further studied. In this review of latest literatures, we comprehensively tease out diverse roles of different kinds of inflammasomes in neuroimmune and neurodegenerative diseases, especially in the perspective of double roles involved in pathogenesis, and identify future research priorities.

Beneficial or Harmful Role of Macrophages in Guillain-Barré Syndrome and Experimental Autoimmune Neuritis

Guillain-Barré syndrome (GBS), an immune-mediated demyelinating peripheral neuropathy, is characterized by acute weakness of the extremities and areflexia or hyporeflexia. Experimental autoimmune neuritis (EAN) is a common animal model for GBS, which represents a CD4+ T cell-mediated inflammatory autoimmune demyelination of the peripheral nervous system (PNS), and is used to investigate the pathogenic mechanism of GBS. It has been found that macrophages play a critical role in the pathogenesis of both GBS and EAN. Macrophages have been primarily classified into two major phenotypes: proinflammatory macrophages (M1) and anti-inflammatory macrophages (M2). The two different macrophage subsets M1 and M2 may play a decisive role in initiation and development of GBS and EAN. However, recently, it has been indicated that the roles of macrophages in immune regulation and autoimmune diseases are more complex than those suggested by a simple M1-M2 dichotomy. Macrophages might exert either inflammatory or anti-inflammatory effect by secreting pro- or anti-inflammatory cytokines, and either inducing the activation of T cells to mediate immune response, resulting in inflammation and demyelination in the PNS, or promoting disease recovery. In this review, we summarize the dual roles of macrophages in GBS and EAN and explore the mechanism of macrophage polarization to provide a potential therapeutic approach for GBS in the future.

More severe manifestations and poorer short-term prognosis of ganglioside-associated Guillain–Barré syndrome in northeast China

Ganglioside as a neurotrophic drug has been hitherto widely used in China, although Guillain–Barré syndrome (GBS) following intravenous ganglioside treatment was reported in Europe several decades ago, leading to its withdrawal from European market. We identified 7 patients who developed GBS after intravenous use of gangliosides (the ganglioside+ group) and compared their clinical data with those of 77 non-ganglioside-associated GBS patients (the ganglioside− group) in 2013, aiming at gaining the distinct features of ganglioside-associated GBS. Although the mean age, the protein levels in cerebrospinal fluid (CSF) and the frequency of cranial nerve involvement were similar between the two groups, the Hughes Functional Grading Scale (HFGS) score and the Medical Research Council (MRC) sum score at nadir significantly differed (4.86 versus 3.64; 7.71 versus 36.87, both p b 0.001), indicating a higher disease severity of gangliosideassociated GBS. This was further evidenced by a significantly higher ratio of patients with ganglioside-associated GBS who required mechanical ventilation (85.71% versus 15.58%, p b 0.01). The short-term prognosis of ganglioside-associated GBS, as measured by the HFGS score and the MRC sum score at discharge, was poorer (4.29 versus 2.82; 17.29 versus 45.96, both p b 0.001). All the patients in the ganglioside+ group presented an axonal form of GBS, namely acute motor axonal neuropathy (AMAN). When compared with the AMAN patients in the ganglioside− group, more severe functional deficits at nadir and poorer recovery after standard treatment were still prominent in ganglioside-associated GBS. Anti-GM1 and anti-GT1a antibodies were detectable in patients with AMAN while not in patients with the demyelinating subtype of GBS. The concentrations of these antibodies in patients with AMAN were insignificantly different between the ganglioside+ and the ganglioside− groups. In sum, ganglioside-associated GBS is a devastating side effect of intravenous use of ganglioside, which usually manifests a more severe clinical course and poorer outcome.