Role of tissue plasminogen activator and plasminogen activator inhibitor as potential biomarkers in psychosis

Pathophysiological Hypothesis of COVID-19 Psychosis

ABSTRACT

In December 2019, a new coronavirus called SARS-CoV-2 was discovered in patients with pneumonia of unknown cause. Although respiratory symptoms mainly characterize infection by this virus, neuropsychiatric manifestations of the disease are becoming more and more frequent. Among them, the appearance of psychotic outbreaks in patients experiencing the infection or after a short time after it has resolved is remarkable. This narrative review aims to describe the possible relationship between SARS-CoV-2 and the onset of psychosis by developing the neurotropic capacities of the virus and analyzing the neurobiology of psychoses.

Hypercoagulable state in patients with schizophrenia: different effects of acute and chronic antipsychotic medications

Background

Previous studies reported higher incidences of venous thromboembolism and cardiovascular disease in schizophrenia patients and higher indicators of thrombosis, thrombocyte activation, and platelet dysfunction.

Objectives

To check if first-episode schizophrenia (FES) patients have a hypercoagulable state and determine whether acute and chronic antipsychotics have the same effect on blood coagulation or fibrinolysis-related biomarkers.

Design

Case-control study.

Methods

A total of 81 participants were grouped in FES, chronic schizophrenia (CS), and healthy controls (HCs). In addition to demographic data and clinical characteristics, immunological analyses were performed to measure plasma levels of D-dimer, plasminogen activator inhibitor-1 (PAI-1), soluble P selectin (sP-sel), tissue plasminogen activator (tPA), thrombotic precursor protein (TpP), and von Willebrand's disease factor (vWF).

Results

Compared to HC group, FES patients showed higher PAI-1 (28.61 ng/ml versus 15.69 ng/ml), sP-sel (2.78 ng/ml versus 1.18 ng/ml), and TpP (15.61 µg/ml versus 5.59 µg/ml) along with a higher PAI-1/tPA (3.12 versus 2.00). Acute antipsychotic medication reduced higher PAI-1 (28.61 → 21.99), sP-sel (2.78 → 1.87), tPA (9.59 → 5.83), TpP (15.61 → 10.54), and vWF (383.18 → 291.08) in FES patients. However, plasma sP-sel and vWF in CS patients returned to the pre-treatment levels in FES patients, and PAI-1/tPA significantly decreased compared to FES patients.

Conclusion

These results suggest a hypercoagulable state in FES patients and demonstrate contrast effects of acute and chronic antipsychotics on coagulation or fibrinolysis in schizophrenia patients.

Vascular-related biomarkers in psychosis: a systematic review and meta-analysis

Background

While the molecular underpinnings of vascular dysfunction in psychosis are under active investigation, their implications remain unclear due to inconsistent and sometimes sparse observations. We conducted a comprehensive meta-analysis to critically assess the alterations of vascular-related molecules in the cerebrospinal fluid (CSF) and blood of patients with psychotic disorders compared with healthy individuals.

Methods

Databases were searched from inception to February 23, 2023. Meta-analyses were performed using a random-effects model. Meta-regression and subgroup analyses were conducted to assess the effects of clinical correlates.

Results

We identified 93 eligible studies with 30 biomarkers investigated in the CSF and/or blood. Among the biomarkers examined, psychotic disorders were associated with elevated CSF-to-serum albumin ratio (standardized mean difference [SMD], 0.69; 95% confidence interval [CI], 0.35-1.02); blood S100B (SMD, 0.88; 95% CI, 0.59-1.17), matrix metalloproteinase-9 (MMP-9; SMD, 0.66; 95% CI, 0.46-0.86), and zonulin (SMD, 1.17; 95% CI, 0.04-2.30). The blood levels of S100B, MMP-9, nerve growth factor (NGF), vascular endothelial growth factor (VEGF), intercellular adhesion molecule 1 (ICAM-1), and vascular adhesion molecule 1 (VCAM-1) were altered in patient subgroups differing in demographic and clinical characteristics. Blood S100B level was positively correlated with age and duration of illness. Substantial between-study heterogeneity was observed in most molecules.

Conclusion

The alterations in certain vascular-related fluid markers in psychotic disorders suggest disturbances in normal vascular structures and functions. However, not all molecules examined displayed clear evidence of changes. While potential impacts of clinical factors, including the administered treatment, were identified, the exploration remained limited. Further studies are needed to investigate the diverse patterns of expression, and understand how these abnormalities reflect the pathophysiology of psychosis and the impact of clinical factors.

A role for endothelial NMDA receptors in the pathophysiology of schizophrenia

Numerous genetic and postmortem studies link N-methyl-d-aspartate receptor (NMDAR) dysfunction with schizophrenia, forming the basis of the popular glutamate hypothesis. Neuronal NMDAR abnormalities are consistently reported from both basic and clinical experiments, however, non-neuronal cells also contain NMDARs, and are rarely, if ever, considered in the discussion of glutamate action in schizophrenia. We offer an examination of recent discoveries elucidating the actions and consequences of NMDAR activation in the neuroendothelium. While there has been mixed literature regarding blood flow alterations in the schizophrenia brain, in this review, we posit that some common findings may be explained by neuroendothelial NMDAR dysfunction. In particular, we emphasize that endothelial NMDARs are key mediators of neurovascular coupling, where increased neuronal activity leads to increased blood flow. Based on the broad conclusions that hypoperfusion is a neuroanatomical finding in schizophrenia, we discuss potential mechanisms by which endothelial NMDARs contribute to this disorder. We propose that endothelial NMDAR dysfunction can be a primary cause of neurovascular abnormalities in schizophrenia. Importantly, functional MRI studies using BOLD signal as a proxy for neuron activity should be considered in a new light if neurovascular coupling is impaired in schizophrenia. This review is the first to propose that NMDARs in non-excitable cells play a role in schizophrenia.

Can the Imbalance between Neurotrophic and Apoptotic Proteins Be the "Beware the Ides of March" for Unaffected Relatives of Schizophrenia Patients?

Schizophrenia (SZ) is a mental disorder with a strong genetic basis as well as epigenetic aspects. Siblings of patients with SZ can share certain endophenotypes with the patients, suggesting that siblings may be important for distinguishing between trait and state markers. In the current study, we aimed to characterize the balance between pro-BDNF/mature BDNF and its receptors p75NTR/TrkB, which are tPA-BDNF pathways proteins and are thought to play a role in synaptic pruning, as a possible endophenotype of schizophrenia. Forty drug-naïve patients with first-episode psychosis (FEP) matched for age, gender, and level of education, 40 unaffected siblings (UAS) of patients with FEP, and 67 healthy controls (HC) were included in the study. Blood samples were collected from all participants to determine BDNF, pro-BDNF, TrkB and p75NTR, PAI1, tPA, ACTH, and cortisol levels. We showed that levels of proteins of the tPA-BDNF pathway as well as the pro-BDNF/m-BDNF and p75NTR/TrkB ratios could successfully differentiate FEP and their siblings from the HCs by using ROC analysis. Plasma levels of m-BDNF were found to be the lowest in the healthy siblings and highest in the HCs with statistically significant differences between all 3 groups. The plasma level of pro-BDNF in the HC group was similar to the FEP patients, the same in the healthy siblings of the FEP patients. Our data support the hypothesis that imbalance between neurotrophic and apoptotic proteins might occur in SZ and this imbalance could be an endophenotype of the disease.

Targeting NMDA Receptors at the Neurovascular Unit: Past and Future Treatments for Central Nervous System Diseases

The excitatory neurotransmission of the central nervous system (CNS) mainly involves glutamate and its receptors, especially N-methyl-D-Aspartate receptors (NMDARs). These receptors have been extensively described on neurons and, more recently, also on other cell types. Nowadays, the study of their differential expression and function is taking a growing place in preclinical and clinical research. The diversity of NMDAR subtypes and their signaling pathways give rise to pleiotropic functions such as brain development, neuronal plasticity, maturation along with excitotoxicity, blood-brain barrier integrity, and inflammation. NMDARs have thus emerged as key targets for the treatment of neurological disorders. By their large extracellular regions and complex intracellular structures, NMDARs are modulated by a variety of endogenous and pharmacological compounds. Here, we will present an overview of NMDAR functions on neurons and other important cell types involved in the pathophysiology of neurodegenerative, neurovascular, mental, autoimmune, and neurodevelopmental diseases. We will then discuss past and future development of NMDAR targeting drugs, including innovative and promising new approaches.

Dysregulation of complement and coagulation pathways: emerging mechanisms in the development of psychosis

Early identification and treatment significantly improve clinical outcomes of psychotic disorders. Recent studies identified protein components of the complement and coagulation systems as key pathways implicated in psychosis. These specific protein alterations are integral to the inflammatory response and can begin years before the onset of clinical symptoms of psychotic disorder. Critically, they have recently been shown to predict the transition from clinical high risk to first-episode psychosis, enabling stratification of individuals who are most likely to transition to psychotic disorder from those who are not. This reinforces the concept that the psychosis spectrum is likely a central nervous system manifestation of systemic changes and highlights the need to investigate plasma proteins as diagnostic or prognostic biomarkers and pathophysiological mediators. In this review, we integrate evidence of alterations in proteins belonging to the complement and coagulation protein systems, including the coagulation, anticoagulation, and fibrinolytic pathways and their dysregulation in psychosis, into a consolidated mechanism that could be integral to the progression and manifestation of psychosis. We consolidate the findings of altered blood proteins relevant for progression to psychotic disorders, using data from longitudinal studies of the general population in addition to clinical high-risk (CHR) individuals transitioning to psychotic disorder. These are compared to markers identified from first-episode psychosis and schizophrenia as well as other psychosis spectrum disorders. We propose the novel hypothesis that altered complement and coagulation plasma levels enhance their pathways' activating capacities, while low levels observed in key regulatory components contribute to excessive activation observed in patients. This hypothesis will require future testing through a range of experimental paradigms, and if upheld, complement and coagulation pathways or specific proteins could be useful diagnostic or prognostic tools and targets for early intervention and preventive strategies.

Association between plasminogen activator inhibitor-1 gene polymorphisms and susceptibility to Parkinson's disease in Chinese patients

PURPOSE

Parkinson's disease (PD) is a neurodegenerative disease that usually leads to memory impairment, cognitive decline and dementia. Previous studies have reported that plasminogen activator inhibitor-1 (PAI-1) gene polymorphisms play important roles in cardiovascular diseases, obesity, inflammation and other diseases. However, the role of PAI-1 in the diagnosis of Parkinson's disease has not been reported so far.

METHODS

This study was a case-control study. This study included 131 PD patients and 97 healthy volunteers. polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to analyze the polymorphic loci of five different regions in PAI-1 gene (rs2227631, rs1799889, rs6092, rs2227694 and rs7242). 60 PD patients and 60 healthy volunteers were selected to detect the plasma PAI-1 concentration. The allele and genotype frequencies of SNPs were assessed using the SHEsis program.

RESULTS

We found that GG genotype frequency and G allele frequency of rs2227631 was significantly higher in the PD patients. Statistically significant difference for rs1799889 could be observed in overdominant model. In subgroup analysis, a significant difference in genotype frequency distribution and allele frequency was found for rs2227631 and rs1799889 between early-onset PD group and the control group. For cognitive dysfunction, the subcomponent showed that GG genotype frequency and G allele frequency of rs2227631 was significantly higher in normal cognition group. The codominant model of rs1799889 was significantly different between the cognitive impairment group and the control group. In addition, the expression of PAI-1 in plasma of PD patients was significantly higher than that of controls, and further analysis showed that the expression of PAI-1 in patients with cognitive impairment was significantly higher than that in patients with cognitive normal.

CONCLUSION

Our results indicate that the PAI-1 gene rs2227631 and rs1799889 polymorphisms were significantly associated with PD susceptibility in the Chinese Han population. PAI-1 has the potential to become a new therapeutic target and diagnostic marker.

Proteolytic cleavage of proBDNF to mBDNF in neuropsychiatric and neurodegenerative diseases

Brain-derived neurotrophic factor (BDNF) is involved in pathophysiological mechanisms in neuropsychiatric diseases, including depression, anxiety, and schizophrenia (SZ), as well as neurodegenerative diseases like Parkinson's disease (PD) and Alzheimer's disease (AD). An imbalance or insufficient pro-brain-derived neurotrophic factor (proBDNF) transformation into mature BDNF (mBDNF) is potentially critical to the disease pathogenesis by impairing neuronal plasticity as suggested by results from many studies. Thus, promoting proBDNF transformation into mBDNF is therefore hypothesized as beneficial for the treatment of neuropsychiatric and neurodegenerative diseases. ProBDNF is proteolytically cleaved into the mBDNF by intracellular furin/proprotein convertases and extracellular proteases (plasmin/matrix metallopeptidases). This article reviews the mechanisms of the conversion of proBDNF to mBDNF and the research status of intracellular/extracellular proteolytic proteases for neuropsychiatric and neurodegenerative disorders.

Predictive value of oxidative stress biomarkers in drug‑free patients with schizophrenia and schizo-affective disorder

Several studies have suggested that oxidative stress may represent one of the primary etiological mechanisms of schizophrenia (SZ) and schizoaffective disorder (SAD) which can be targeted by therapeutic intervention. The present study was conducted over a period of 24 months, between June 2016 and June 2018. All enrolled subjects were Tunisian, forty five drug‑free male patients with SZ (mean age: 37.6 years), twenty one drug‑free male patients with SAD (mean age: 28.8 years) and hundred and one age and gender matched controls (mean age: 34.2 years) were enrolled in the study. Plasma reduced glutathione (GSH) and Total thiols levels were significantly decreased in patients compared to controls (respectively p<0.001; p=0.050). In addition, malondialdehyde (MDA), advanced oxidation protein products (AOPP) and protein carbonyls (PC) concentrations and glutathione peroxidase (GSH-Px) activity were significantly increased in patients compared to controls (p<0.001; p<0.001; p<0.001 and p=0.003 respectively). The binary logistic regression analysis revealed that MDA, AOPP, PC and GSH-Px could be considered as independent risk factors for SZ and SAD. When using ROC analysis, a remarkable increase in the area under the curve (AUC) with higher sensitivity (Se) and specificity (Sp) for MDA, AOPP, PC and GSH-Px combined markers was observed. The present study indicated that the identification of the predictive value of this four-selected biomarkers related to oxidative stress in drug free patients should lead to a better identification of the etiological mechanism of SZ or SAD.

[Platelets, hemostasis and mental disorders]

Platelets are an easily accessible model for the study of biochemical mechanisms of mental diseases, including schizophrenia and depression. This literature review addresses a role of platelet activation in the pathogenesis of mental diseases. Platelet activation observed in patients with schizophrenia, depression and other mental illnesses is associated with the development of cardiovascular disease and an increased risk of thrombotic complications, which can be the main cause of morbidity and mortality in patients with mental disorders. A deeper understanding of the biochemical mechanisms of mental disorders will help in the study of clinical consequences of these disorders and in choosing the right therapeutic strategy for patients.