Contralateral C7 nerve transfer in the treatment of upper-extremity paralysis: a review of anatomical basis, surgical approaches, and neurobiological mechanisms.

The previous three decades have witnessed a prosperity of contralateral C7 nerve (CC7) transfer in the treatment of upper-extremity paralysis induced by both brachial plexus avulsion injury and central hemiplegia. From the initial subcutaneous route to the pre-spinal route and the newly-established post-spinal route, this surgical operation underwent a series of innovations and refinements, with the aim of shortening the regeneration distance and even achieving direct neurorrhaphy. Apart from surgical efforts for better peripheral nerve regeneration, brain involvement in functional improvements after CC7 transfer also stimulated scientific interest. This review summarizes recent advances of CC7 transfer in the treatment of upper-extremity paralysis of both peripheral and central causes, which covers the neuroanatomical basis, the evolution of surgical approach, and central mechanisms. In addition, motor cortex stimulation is discussed as a viable rehabilitation treatment in boosting functional recovery after CC7 transfer. This knowledge will be beneficial towards improving clinical effects of CC7 transfer.

Circulating Treg cells from patients with cerebral aneurysms displayed deficiency in ICOS expression and function.

Inducible costimulator (ICOS) is a member of the CD28 family. When activated, ICOS signalling promotes FOXP3 CNS2 gene demethylation and stabilizes Treg differentiation. Cerebral aneurysm (CA) is the local ballooning of the cerebral vasculature, characterized by higher levels of inflammation mediators and tissue remodelling. FOXP3+ Treg cell dysfunction may contribute to CA pathogenesis. In this study, the expression and function of ICOS in Treg cells was investigated. Circulating CD4+ CD25hi T cells from CA subjects demonstrated significantly lower levels of ICOS expression than circulating CD4+ CD25hi T cells from healthy subjects. In both healthy subjects and CA subjects, FOXP3+ Treg cells were highly concentrated in the ICOS+ fraction of CD4+ CD25hi T cells. Anti-ICOS costimulation, in combination with anti-CD3 and IL-2, significantly increased FOXP3 expression in CD4+ CD25hi ICOS+ T cells but not in CD4+ CD25hi ICOS- T cells. In addition, anti-CD3/IL-2 and anti-ICOS costimulation significantly elevated the expression of IL-10 and TGF-ß, decreased the expression of IL-17, and enhanced CD4+ CD25hi ICOS+ T cell-mediated suppression of autologous CD4+ CD25- Tconv proliferation. Interestingly, CD4+ CD25hi ICOS+ T cells from CA subjects presented lower responsiveness toward anti-ICOS costimulation than CD4+ CD25hi ICOS+ T cells from healthy subjects. Overall, these results demonstrated that ICOS signalling could significantly improve FOXP3 expression and enhance Treg functional potency. However, circulating Treg cells from CA patients displayed reduced ICOS expression and lower responsiveness toward anti-ICOS stimulation.

Regulatory T cells demonstrate significantly increased functions following stimulation with IL-2 in a Tim-3-dependent manner in intracranial aneurysms.

The formation of intracranial aneurysm (IA) is associated with the destruction of various cellular and structural components, which induces pathogenic inflammatory responses that further propagate tissue damage. The regulatory immune system can suppress exacerbated inflammation and offer tissue protection; however, previous studies by others and us have demonstrated that the regulatory T (Treg) cells were functionally impaired in IA patients. Hence, strategies that can improve Treg function in IA patients should be investigated. Based on our previous finding that IL-2 strongly elevated the expression of the checkpoint molecule Tim-3 in Treg cells, we examined the effect of IL-2 in the function of Treg cells from IA patients. External IL-2 significantly improved the proliferation of Treg cells, increased the expression of CTLA-4 and LAG-3, and enhanced Treg-mediated suppression of conventional T cell (Tconv) proliferation. Importantly, compared to the Tim-3- Treg cells, the Tim-3+ Treg cells presented comparable proliferation capacity, but significantly greater expressions of CTLA-4 and LAG-3 and significantly higher capacity to suppress Tconv proliferation. In addition, blocking Tim-3 abrogated IL-2-mediated enhancement of Tim-3+ Treg cells. We then investigated the IL-2 level in IA patients, and found that although IA patients and healthy controls presented similar serum IL-2 concentration, the concentrations of IL-1ß and TNF-α were significantly higher in IA patients than in healthy controls, signaling a relative reduction in IL-2 abundance. Together, we found that IL-2 could significantly enhance the function of Treg cells from IA patients in a Tim-3-dependent manner.

Patients with intracranial aneurysms presented defects in regulatory T cells, which were associated with impairment in Tim-3 upregulation.

Pathogenic inflammation contributes to aneurysm formation by mediating the destruction of the endothelium and the extracellular matrix and promoting pathogenic proliferation of smooth muscle cells. In mouse models, tolerance-inducing T regulatory (Treg) cells could significantly reduce the incidence and severity of aneurysms. Hence, it should be investigated why in human intracranial aneurysm (IA) patients, Treg cells failed to provide protection against aneurysm formation. In this study, the frequency and function of Treg cells in IA patients were examined. The frequency of Foxp3+ Treg cells was significantly lower in IA patients than in healthy controls. This downregulation was only specific to the Treg subset of CD4+ T cells, as the frequency of total CD4+ T cell was increased in IA patients. Subsequently, we found that the expressions of Treg-associated molecules, including Foxp3, CTLA-4, TGF-ß, and IL-10, were significantly lower in Foxp3+ Treg cells from IA patients than in Foxp3+ Treg cells from healthy controls. In both healthy controls and IA patients, Foxp3+ Treg cells were distinguished into a more potent Tim-3+ subset and a less potent Tim-3- subset. The Tim-3+ subset of Foxp3+ Treg cells was significantly reduced in IA patients. Signaling via IL-2, IL-7, IL-15 and IL-21 was shown to promote Tim-3 upregulation in CD4+ and CD8+ T cells. Interestingly, we found that Tim-3 could be upregulated in Treg cells via the same mechanism, but compared to the Treg cells from healthy controls, the Treg cells from IA patients presented defects in Tim-3 upregulation upon cytokine stimulation. Together, our results demonstrated that Foxp3+ Treg cells in IA patients presented reduced function, which was associated with a defect in Tim-3 upregulation.

Soluble galectin 9 potently enhanced regulatory T-cell formation, a pathway impaired in patients with intracranial aneurysm.

Patients with intracranial aneurysm (IA) present a dysregulated immune system with lower frequency of regulatory T (Treg) cells. Here, we examined whether galectin 9 (Gal-9), the natural ligand of Tim-3, could promote Treg cells in IA patients. We first discovered that the intracellular and extracellular Gal-9 was primarily expressed by CD4+ CD25- T conventional (Tconv) cells, and also by monocytes at lower levels, but rarely by CD4+ CD25+ Treg cells. In IA patients, the Gal-9 expression was significantly lower than in healthy controls. CD4+ CD25- Tconv cells could be induced into Foxp3-expressing induced Treg (iTreg) cells using a TGF-ß-containing milieu. We found that soluble Gal-9 significantly enhanced this process by potently upregulating the expression of Foxp3, IL-10 and TGF-ß in a concentration-dependent manner. In addition, in the absence of additional Gal-9, the level of Foxp3 upregulation was directly correlated with the level of intrinsic Gal-9 expression. Notably, the strength of external Gal-9-mediated effects was significantly lower in IA patients than in healthy controls. Using a Tim-3 blocking antibody, we found that the promotion of iTreg development by soluble Gal-9 was dependent on the Tim-3 signalling pathway. Overall, our investigations demonstrated that Gal-9 presented a critical role in the development of iTreg cells. However, this mechanism was impaired in IA patients due to lower expression of both Gal-9 and Tim-3.

Dysregulation of CD4(+) T Cell Subsets in Intracranial Aneurysm.

Intracranial aneurysms (IAs) and potential IA rupture are one of the direct causes of permanent brain damage and mortality. Interestingly, the major risk factors of IA development, including hemodynamic stress, hypertension, smoking, and genetic predispositions, are closely associated with a proinflammatory immune status. Therefore, we examined the roles of CD4(+) T cells in IA pathogenesis. IA patients exhibited peripheral CD4(+) T-cell imbalance, with overrepresented T helper 1 (Th1) and Th17 activities and underrepresented Th2 and regulatory T (Treg) activities, including increased IFN-γ, TNF-α, and IL-17 production and decreased IL-10 production from total CD4(+) T cells. Chemokine receptors CXCR3 and CCR6 were used to identify Th1, Th2, and Th17 cell subsets, and CD4(+)CD25(hi) was used to identify Treg cells. Based on these markers, the data then showed altered cytokine production by each cell type and shifted subpopulation frequency. Moreover, this shift in frequency was directly correlated with IA severity. To examine the underlying mechanism of CD4(+) T cell skewing, we cocultured CD4(+) T cells with autologous monocytes and found that coculture with monocytes could significantly increase IFN-γ and IL-17 production through contact-independent mechanisms, demonstrating that monocytes could potentially contribute to the altered CD4(+) T cell composition in IA. Analyzing mRNA transcripts revealed significantly upregulated IL-1ß and TNF-α expression by monocytes from IA patients. We found a loss of CD4(+) T cell subset balance that was likely to promote a higher state of inflammation in IA, which may exacerbate the disease through a positive feedback loop.

Downregulation of T cell immunoglobulin and mucin protein 3 in the pathogenesis of intracranial aneurysm.

Evidence has shown that inflammation acts as a critical contributor to the pathogenesis of intracranial aneurysm (IA), a potentially devastating clinical problem. T cell immunoglobulin and mucin protein 3 (Tim-3) is a negative regulatory molecule and plays important roles in the inflammation process. In the current study, we investigated the expression of Tim-3 and its correlation with tumor necrosis factor alpha (TNF-α) in IA patients. Data showed that both messenger RNA (mRNA) level and protein level of Tim-3 were significantly decreased in CD4+ T cells and CD8+ T cells from IA patients than from healthy controls (P < 0.001). However, expression of Tim-3 was not altered in monocytes between patients and healthy donors. Further analyses revealed that patients with ruptured aneurysm had significantly lower level of Tim-3 in CD8+ T cells than those with un-ruptured aneurysm. In addition, a negative correlation between serum level of TNF-α and the expression of Tim-3 in CD4+ T cells was observed in IA patients. Similar correlation was also identified in CD8+ T cells from IA patients. Our study suggests that Tim-3 may participate in the development and progression of IA by probably its negative regulation on TNF-α.

Relationship between human cord blood adropin levels and fetal growth.

Adropin is a recently identified peptide and participates in the regulation of energy homeostasis and vascular function. The aim of this study was to examine the relationships between human cord blood adropin levels and fetal growth. A total of 159 newborns [preterm delivery (PTD), n=72; term delivery, n=87] were recruited. Adropin levels in cord blood were determined using enzyme-linked immunosorbent assay kits. Clinical information on fetal growth was collected. Adropin levels in PTD babies (median, 2028; 25th-75th, 1413-2484pg/ml) were lower than those in term delivery babies (median, 2305; 25th-75th, 1960-2684pg/ml, P=0.01). Birth weight and length z score, Ponderal index, placental length, breadth, thickness, surface area, volume and density were not significantly correlated to adropin concentrations in term delivery group. However, we found adropin concentrations were significantly correlated to gestational age at birth (Spearman's correlation coefficient=0.35, P<0.01) and placental weight (Spearman's correlation coefficient=0.24, P=0.04) in PTD group. We also found that boys had lower adropin levels than girls in PTD group (P=0.01). When the analysis was extended to the whole group (PTD and term deliveries combined), the results were similar to those for PTD group alone. After adjusting for maternal age and newborn's sex, every 100pg/ml increase of adropin concentration was significantly associated with a decreased risk of PTD (odds ratio, 0.95; 95% confidence interval, 0.91-0.99). Our study showed that cord blood adropin levels were positively correlated with gestational age and placental weight but not with other fetal growth parameters.

An efficient and non-enzymatic method for isolation and culture of endothelial cells from the nidus of human cerebral arteriovenous malformations.

In this report, we describe an efficient and non-enzymatic method for isolating and culturing endothelial cells (ECs) from the nidus of surgically resected arteriovenous malformation (AVM) specimens. These cultured cells possessed typical phenotypic markers (i.e. von Willebrand factor and CD34), as well as morphological and ultrastructural characteristics of ECs. However, they had activated Notch-1 signaling, which plays a critical role in the development of AVM. The present study suggests that hypoxic endothelial cells from the nidus of human cerebral arteriovenous malformation (CAVMECs) have angiogenic potentials, as our data showed that VEGF gene expression and cell proliferation were more evident with prolonged hypoxia. In our study, we successfully used the vascular tissue explants adherent method to isolate and culture CAVMECs with high purity. This may prove to be a useful tool for studying the molecular mechanisms that mediate abnormal vessel development and maintenance in AVM.

Expression of pro-inflammatory cytokines and the risk of intracranial aneurysm.

Intracranial aneurysm (IA) lingers as a potentially devastating clinical problem, in which inflammation acts as a critical contributor to the pathogenesis of this disease. Cytokines play a major role in regulating inflammation. The aim of this study was to gain insight in the inflammatory response in IA by assessing plasma cytokine profiles. Plasma levels of 10 cytokines were quantified by multiplex protein arrays in 66 patients with IA and 78 healthy controls. Results showed that plasma level of interleukin 1 beta (IL-1ß) was 2.4-fold higher in patients than in controls (p < 0.05). The level of monocyte chemoattractant protein-1 (MCP-1) was 2.8-fold higher in patient than in controls (p < 0.01). The level of tumor necrosis factor-alpha (TNF-α) was 2.1-fold higher in cases than in controls (p < 0.001). When comparing the expression of cytokines in IA patients with different characteristics, cases with ruptured aneurysm revealed increased level of MCP-1 than those with unruptured aneurysm (p < 0.05), whereas cases with multiple numbers of aneurysms demonstrated higher levels of MCP-1 and TNF-α than those with single aneurysm (p < 0.05 and p < 0.05, respectively). These data indicated that IL-1ß, MCP-1, and TNF-α were associated with increased risk of IA and may affect the development of this disease.

Administration of MS-275 improves cognitive performance and reduces cell death following traumatic brain injury in rats.

AIMS: The MS-275 is a selective inhibitor of class I histone deacetylases (HDACs), which has been reported as a potential strategy in some central nervous system diseases associated with neurodegeneration and disturbed learning. However, its role in traumatic brain injury is not well defined. In this study, we examined the behavioral-cognitive performance as well as histology outcome in adult rats to evaluate whether postinjury administration of MS-275 (15 and 45 mg/kg) would provide neuroprotection benefits and ameliorate cognitive deficits following fluid percussion injury. METHODS: Traumatic brain injury (˜2.15 ATMs) was produced using a fluid percussion device with the lateral orientation. MS-275 was administered (15 and 45 mg/kg) systemically once daily for 7 days starting at 30 min after lateral fluid percussion TBI. Acquisition of spatial learning and memory retention was assessed using the Morris water maze (MWM) on days 10-14 after TBI. Brain tissues were collected and stained with Fluoro-Jade B histofluorescence (for degenerating neurons) at 24 h after injury and cresyl violet (for long-term neuronal survival) on day 14 postinjury. RESULTS: Behavioral outcome after TBI revealed MS-275 treatment groups, at all doses examined, performed significantly better in the Morris Water Maze (P < 0.001). Acute histology analysis demonstrated that 45 mg/kg MS-275 significantly reduced the number of degenerating neurons in the ipsilateral CA2-3 hippocampus at 24 h postinjury (P = 0.007). There was a trend for MS-275 to increase the survival of neurons in the CA2-3 hippocampus on 14 days after TBI (P = 0.164). CONCLUSION: Our present data highlight the fact that MS-275 may provide neuroprotective effect and improve cognitive performance after TBI. We concluded that MS-275 is a potential novel treatment and will have an ameliorative effect on some of the pathological features associated with TBI.