Serum levels of matrix metalloproteinase-9 and tissue inhibitors of metalloproteinases 1 in subacute sclerosing panencephalitis

Cognitive Dysfunction in Systemic Lupus Erythematosus: Immunopathology, Clinical Manifestations, Neuroimaging and Management

Cognitive dysfunction (CD) is a common yet often clinically subtle manifestation that considerably impacts the health-related quality of life in patients with systemic lupus erythaematosus (SLE). Given the inconsistencies in CD assessment and challenges in its attribution to SLE, the reported prevalence of CD differs widely, ranging from 3 to 88%. The clinical presentation of CD in SLE is non-specific and may manifest concurrently with overt neuropsychiatric illness such as psychosis or mood disorders or as isolated impairment of attention, working memory, executive dysfunction or processing speed. Despite the lack of standardized and sensitive neuropsychological tests and validated diagnostic biomarkers of CD in SLE, significant progress has been made in identifying pathogenic neural pathways and neuroimaging. Furthermore, several autoantibodies, cytokines, pro-inflammatory mediators and metabolic factors have been implicated in the pathogenesis of CD in SLE. Abrogation of the integrity of the blood-brain barrier (BBB) and ensuing autoantibody-mediated neurotoxicity, complement and microglial activation remains the widely accepted mechanism of SLE-related CD. Although several functional neuroimaging modalities have consistently demonstrated abnormalities that correlate with CD in SLE patients, a consensus remains to be reached as to their clinical utility in diagnosing CD. Given the multifactorial aetiology of CD, a multi-domain interventional approach that addresses the risk factors and disease mechanisms of CD in a concurrent fashion is the favourable therapeutic direction. While cognitive rehabilitation and exercise training remain important, specific pharmacological agents that target microglial activation and maintain the BBB integrity are potential candidates for the treatment of SLE-related CD.

TIMP1 preserves the blood-brain barrier through interacting with CD63/integrin 1 complex and regulating downstream FAK/RhoA signaling

Blood-brain barrier (BBB) breakdown and the associated microvascular hyperpermeability are hallmark features of several neurological disorders, including traumatic brain injury (TBI). However, there is no viable therapeutic strategy to rescue BBB function. Tissue inhibitor of metalloproteinase-1 (TIMP1) has been considered to be beneficial for vascular integrity, but the molecular mechanisms underlying the functions of TIMP1 remain elusive. Here, we report that TIMP1 executes a protective role on neuroprotective function via ameliorating BBB disruption in mice with experimental TBI. In human brain microvessel endothelial cells (HBMECs) exposed to hypoxia and inflammation injury, the recombinant TIMP1 (rTIMP1) treatment maintained integrity of junctional proteins and trans-endothelial tightness. Mechanistically, TIMP1 interacts with CD63/integrin β1 complex and activates downstream FAK signaling, leading to attenuation of RhoA activation and F-actin depolymerization for endothelial cells structure stabilization. Notably, these effects depend on CD63/integrin β1 complex, instead of the MMP-inhibitory function. Together, our results identified a novel MMP-independent function of TIMP1 in regulating endothelial barrier integrity. Therapeutic interventions targeting TIMP1 and its downstream signaling may be beneficial to protect BBB function following brain injury and neurological disorders.

Differential Response Following Infection of Mouse CNS with Virulent and Attenuated Vaccinia Virus Strains

Viral infections of the central nervous system (CNS) lead to a broad range of pathologies. CNS infections with Orthopox viruses have been mainly documented as an adverse reaction to smallpox vaccination with vaccinia virus. To date, there is insufficient data regarding the mechanisms underlying pathological viral replication or viral clearance. Therefore, informed risk assessment of vaccine adverse reactions or outcome prediction is limited. This work applied a model of viral infection of the CNS, comparing neurovirulent with attenuated strains. We followed various parameters along the disease and correlated viral load, morbidity, and mortality with tissue integrity, innate and adaptive immune response and functionality of the blood–brain barrier. Combining these data with whole brain RNA-seq analysis performed at different time points indicated that neurovirulence is associated with host immune silencing followed by induction of tissue damage-specific pathways. In contrast, brain infection with attenuated strains resulted in rapid and robust induction of innate and adaptive protective immunity, followed by viral clearance and recovery. This study significantly improves our understanding of the mechanisms and processes determining the consequence of viral CNS infection and highlights potential biomarkers associated with such outcomes.

Serum matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 levels in patients with tick-borne encephalitis

OBJECTIVES

Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) play important roles in the function of the blood-brain barrier (BBB). To investigate the function of the BBB during tick-borne encephalitis (TBE), the levels of MMP-9 and its common tissue inhibitor, TIMP-1, were measured in serum from patients with acute phase of TBE.

METHODS

Serum MMP-9 and TIMP-1 levels were measured in 147 patients with TBE and 153 controls by ELISA.

RESULTS

Serum MMP-9 levels and MMP-9/TIMP-1 ratios of TBE patients were significantly higher than controls (p < 0.0001 and p < 0.005, respectively). There were no significant differences in serum TIMP-1 levels between TBE patients and controls. Serum MMP-9 and TIMP-1 levels and MMP-9/TIMP-1 ratios were not associated with age of the patients. However, TBE-positive males with TBE had higher levels of MMP-9 than TBE-positive females (p < 0.05).

CONCLUSIONS

Our results suggest that the increased serum level of MMP-9 and MMP-9/TIMP-1 ratio is associated with the pathogenesis of TBE. Serum MMP-9 can serve as an indicator of breakdown of the BBB and inflammatory brain damage during TBE.

Matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in perinatal asphyxia

Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) play important roles in the function of the blood-brain-barrier (BBB). We investigated the roles of MMP-9 and TIMP-1 in the pathogenesis of hypoxic-ischemic encephalopathy following perinatal asphyxia. Serum concentrations of MMP-9 and TIMP-1 were determined by ELISA in 12 neonates with perinatal asphyxia and 15 controls on the birth day and the next day. Serum MMP-9 concentrations in asphyxiated neonates with neurological sequelae (n=5) were significantly higher than concentration in asphyxiated neonates without sequelae (n=7) and controls on birth day (p=0.003 and p<0.001, respectively). The ratios of serum MMP-9/TIMP-1 on birth day in asphyxiated neonates with neurological sequelae were significantly higher than those in asphyxiated neonates without sequelae (p=0.048). There were no significant differences in the serum MMP-9 concentrations or the ratios of MMP-9/TIMP-1 between asphyxiated neonates with and without neurological sequelae on the day after birth. Our preliminary study suggests that serum MMP-9 levels on birth day are important for predicting neurological prognosis of neonates with asphyxia.

MMP-9 and TIMP-1 in the cord blood of premature infants developing BPD

We investigated matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) levels in the cord blood of 29 premature infants who were <30 weeks gestation. One, 8, and 14 infants developed severe, moderate and mild bronchopulmonary dysplasia (BPD), respectively, and 6 did not. MMP-9 and TIMP-1 levels in the cord blood were determined by ELISA. MMP-9/TIMP-1 ratios in the cord blood of infants who developed severe or moderate BPD (n = 9) were significantly higher than those who developed mild BPD or did not develop BPD (n = 20; P = 0.015). Multivariate linear regressions demonstrated that MMP-9 levels and MMP-9/TIMP-1 ratios in the cord blood of the premature infants correlated with the oxygen supplementation period (r = 0.58, P = 0.003 and r = 0.41, P = 0.030, respectively). The MMP-9 levels and MMP-9/TIMP-1 ratios correlated with the severity of maternal chorioamnionitis (both trend P = 0.006). The MMP-9 levels and MMP-9/TIMP-1 ratios in the cord blood may be related to the pathogenesis and severity of BPD and maternal chorioamnionitis.

Roles of matrix metalloproteinase-9 and tissue inhibitors of metalloproteinases 1 in acute encephalopathy following prolonged febrile seizures

Prolonged febrile seizures may be followed by acute encephalopathy with neurological sequelae. To investigate the function of the blood-brain-barrier (BBB) in acute encephalopathy following prolonged febrile seizures with neurological sequelae (AEPFS), the concentrations of serum matrix metalloproteinase-9 (MMP-9) and tissue inhibitors of metalloproteinases 1 (TIMP-1) were measured by ELISA in 10 children with AEPFS, 16 with prolonged febrile seizures without encephalopathy (PFS), 20 with simple febrile seizures (SFS), 23 with convulsive status epilepticus (CSE), and 18 with West syndrome. Serum MMP-9 levels in AEPFS and PFS patients were significantly higher than those in SPS and West syndrome patients and in controls, and those in CSE patients were significantly higher than in controls. Serum TIMP-1 levels in AEPFS patients were significantly lower than those in PFS, SFS, CSE and West syndrome patients and in controls. Serum MMP-9 levels and MMP-9/TIMP-1 ratios in AEPFS patients with motor paralysis were significantly higher than for those without motor paralysis. Our results suggest that prolonged seizures are related to high serum MMP-9 levels, and that an increased MMP-9/TIMP-1 ratio in AEPFS might induce dysfunction of the BBB. Furthermore, an imbalance of serum MMP-9 and TIMP-1 levels in patients with AEPFS may be associated with severe neurological sequelae.