Improvement of Psychotic Symptoms and the Role of Tissue Plasminogen Activator

Low-density lipoprotein receptor-related protein-1 (LRP1) in the glial lineage modulates neuronal excitability

The low-density lipoprotein related protein receptor 1 (LRP1), also known as CD91 or α-Macroglobulin-receptor, is a transmembrane receptor that interacts with more than 40 known ligands. It plays an important biological role as receptor of morphogens, extracellular matrix molecules, cytokines, proteases, protease inhibitors and pathogens. In the CNS, it has primarily been studied as a receptor and clearance agent of pathogenic factors such as Aβ-peptide and, lately, Tau protein that is relevant for tissue homeostasis and protection against neurodegenerative processes. Recently, it was found that LRP1 expresses the Lewis-X (Lex) carbohydrate motif and is expressed in the neural stem cell compartment. The removal of Lrp1 from the cortical radial glia compartment generates a strong phenotype with severe motor deficits, seizures and a reduced life span. The present review discusses approaches that have been taken to address the neurodevelopmental significance of LRP1 by creating novel, lineage-specific constitutive or conditional knockout mouse lines. Deficits in the stem cell compartment may be at the root of severe CNS pathologies.

What is the Association Between Clinically Diagnosed Psychiatric Illness and Total Joint Arthroplasty? A Systematic Review Evaluating Outcomes, Healthcare Use, and Patient-reported Outcome Measures

BACKGROUND

Studies evaluating the effects of a psychiatric illness on orthopaedic surgical outcomes have yielded mixed results. Because awareness of patient comorbid mental health disorders has become increasingly important to tailor treatment plans, the aim of our systematic review was to present the findings of all studies reporting on the association between clinically diagnosed psychiatric illnesses and total joint arthroplasty (TJA) outcomes and evaluate the quality of evidence to provide a comprehensive summary.

QUESTION/PURPOSE

Is there a consistently reported association between comorbid psychiatric illness and (1) complication risk, (2) readmission rates, (3) healthcare use and discharge disposition, and (4) patient-reported outcome measures (PROMs) after TJA?

METHODS

The PubMed, EBSCO host, Medline, and Google Scholar electronic databases were searched on April 9, 2022, to identify all studies that evaluated outcomes after TJA in patients with a comorbid clinically diagnosed mental health disorder between January 1, 2000, and April 1, 2022. Studies were included if the full-text article was available in English, reported on primary TJA outcomes in patients with clinically diagnosed mental health disorders, included patients undergoing TJA without a psychiatric illness for comparison, and had a minimum follow-up time of 30 days for evaluating readmission rates, 90 days for other perioperative outcomes such as length of stay and complications, and 1-year minimum follow-up if assessing PROMs. Studies that used a mental health screening examination instead of clinical diagnoses were excluded to isolate for verified psychiatric illnesses. Additionally, systematic reviews, case reports, duplicate studies between the databases, and gray literature were excluded. Twenty-one studies were included in our final analysis comprising 31,023,713 patients with a mean age range of 57 to 69 years. Mental health diagnoses included depression, anxiety, bipolar disorder, schizophrenia, major personality disorder, and psychosis as well as concomitant mental disorders. Two reviewers independently evaluated the quality of included studies using the Methodological Index for Nonrandomized Studies (MINORS) tool. The mean MINORS score was 19.5 ± 0.91 of 24, with higher scores representing better study quality. All the articles included were retrospective, comparative studies. Given the heterogeneity of the included studies, a meta-analysis was not performed, and results are instead presented descriptively.

RESULTS

Patients with schizophrenia were consistently reported to have higher odds of medical and surgical complications than patients without psychiatric illness, particularly anemia and respiratory complications. Among studies with the largest sample sizes, patients with depression alone or depression and anxiety had slightly higher odds of complications. Most studies identified higher odds of readmission among patients with depression, schizophrenia, and severe mental illness after TJA. However, for anxiety, there was no difference in readmission rates compared with patients without psychiatric illness. Slightly higher odds of emergency department visits were reported for patients with depression, anxiety, concomitant depression and anxiety, and severe mental illness across studies. When evaluating healthcare use, articles with the largest sample sizes reporting on depression and length of stay or discharge disposition found modestly longer length of stay and greater odds of nonhome discharge among patients with depression. Although several studies reported anxiety was associated with slightly increased total costs of hospitalization, the most robust studies reported no difference or slightly shorter average length of stay. However, the included studies only reported partial economic analyses of cost, leading to relatively superficial evidence. Patients with schizophrenia had a slightly longer length of stay and modestly lower odds of home discharge and cost. Likewise, patients with concomitant depression and anxiety had a slightly longer average length of stay, according to the two articles reporting on more than 1000 patients. Lastly, PROM scores were worse in patients with depression at a minimum follow-up of 1 year after TJA. For anxiety, there was no difference in improvement compared with patients without mental illness.

CONCLUSION

Our systematic review found that individuals with psychiatric illness had an increased risk of postoperative complications, increased length of stay, higher costs, less frequent home discharge, and worse PROM scores after TJA. These findings encourage inclusion of comorbid psychiatric illness when risk-stratifying patients. Attention should focus on perioperative interventions to minimize the risk of thromboembolic events, anemia, bleeding, and respiratory complications as well as adequate pain management with drugs that do not exacerbate the likelihood of these adverse events to minimize emergency department visits and readmissions. Future studies are needed to compare patients with concomitant psychiatric illnesses such as depression and anxiety with patients with either diagnosis in isolation, instead of only comparing patients with concomitant diagnoses with patients without any psychiatric illnesses. Similarly, the results of targeted interventions such as cognitive behavioral therapy are needed to understand how orthopaedic surgeons might improve the quality of care for patients with a comorbid psychiatric illness.

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.

A novel commentary: Investigation of the role of a balance between neurotrophic and apoptotic proteins in the pathogenesis of psychosis via the tPA-BDNF pathway

OBJECTIVE

Many hypotheses have put forward to better understand the pathogenesis of schizophrenia (SZ), such as synaptic pruning, stress-diathesis, neurodevelopment, neurodegeneration and neurotransmitter hypothesis; nonetheless, this pathogenesis still remains a mystery. The current study was designed with the hypothesis that impairment of a balance between pro-BDNF/mature BDNF and their receptors p75NTRK/TrkB may cause synaptic pruning in the pathogenesis of psychotic disorders.

METHODS

Sixty-five drug-naïve patients with first-episode psychosis (FEP) who applied to outpatient clinics and were diagnosed according to DSM-5 as well as 65 healthy controls (HC) were included in the study. Symptoms at the time of evaluation were assessed with the PANSS scale by an experienced psychiatrist. Blood samples were collected from all participants to determine BDNF, pro-BDNF, TrkB and p75NTR, PAI1, tPA, ACTH and cortisol levels.

RESULTS

Mature BDNF, TrkB and PAI-1, tPA levels were significantly lower while the levels of ACTH and cortisol were significantly higher in FEP patients compared to HC. No significant difference was found in pro-BDNF and p75NTR levels between the two independent groups. The pro-BDNF/mature BDNF and the p75NTR/TrkB ratios were significantly higher in FEP patients compared to HC. Moreover, the pro-BDNF/mature BDNF and the p75NTR/TrkB ratios were found to be significantly associated with the pathogenesis of SZ in a hierarchical regression model.

DISCUSSION

Imbalance between neurotrophic and apoptotic proteins such as pro-BDNF/mature BDNF and p75NTR/TrkB may be take part pathogenesis of synaptic pruning in psychotic disorders.

Neuroserpin extends the time window of tPA thrombolysis in a rat model of middle cerebral artery occlusion

Tissue-type plasminogen activator (tPA) is characterized as an effective drug for early thrombolytic therapy in acute cerebral infarction (ACI). However, tPA will increase the risk of hemorrhage if it is used beyond the treatment time window. The study aims to explore the effects of neuroserpin (NSP) on the time window of tPA thrombolysis in ACI and the underlying mechanism. The middle cerebral artery occlusion (MCAO) model was constructed in rats, which were randomly divided into six groups: sham operation group, infarction group, 1-hour thrombolysis group, 1-hour thrombolytic + NSP intervention group, 4-hour thrombolytic group, and 4-hour thrombolysis + NSP intervention group. The neurological changes in rats were evaluated by modified neurological severity scores and rota-rod test. The brain edema and cerebral infarction area were evaluated by dry-wet method and triphenyl tetrazolium chloride staining. The blood-brain barrier (BBB) integrity was examined by Evans blue method. The expressions of malondialdehyde, superoxide dismutase, and glutathione peroxidase in brain were also investigated. The expression of caspase-3 and Bcl-2 in brain tissue and apoptosis of neurons were examined by Western blot analysis and toluidine blue staining. tPA thrombolysis significantly attenuated the neurological impairment in rats with MCAO at 1 hour. Conversely, the effect of tPA thrombolysis at 4 hours after MCAO did not significantly help the recovery of neurological function. However, a combination of tPA treatment and NSP treatment at 4 hours after MCAO markedly ameliorated the neurological impairment, cerebral edema, cerebral infarction volume, BBB injury, oxidative stress products, and neuron apoptosis. NSP can probably expand the time window for tPA treatment to reduce neurological impairment in ACI.

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

The identification of biological markers for psychosis has an impact on its diagnosis, prognosis, and likelihood of treatment response. Tissue plasminogen activator (tPA) is involved in important functions such as synaptic plasticity, long-term potentiation and neurogenesis. Plasminogen activator inhibitor (PAI-1) is the most important inhibitor of tPA. Preliminary studies have shown that schizophrenia patients have lower tPA and higher PAI-1 levels than the general population. The association of tPA and PAI-1 abnormalities with psychotic spectrum disorders, however, remains elusive. Our primary objective was to assess the plasma levels of tPA and PAI-1 in patients experiencing acute psychotic episodes as compared to those in healthy controls. In this prospective case-control study, we collected peripheral blood samples from psychiatric inpatients and healthy age, gender and race-matched subjects and determined plasma levels of tPA and PAI-1 by enzyme-linked immune-absorbent assays. Plasma levels of PAI-1 in patients with schizoaffective disorder were significantly lower as compared to those in control subjects (P = 0.03). tPA was lower in cases as compared to controls although it did not reach statistical significance. Asian patients and controls had lower PAI-1 levels. Further, Asian patients with schizoaffective disorder had significantly lower PAI-1 level compared to Asian patients with schizophrenia. Our results indicate that patients with schizoaffective disorder have lower PAI-1 levels than those with schizophrenia, affective psychosis, and healthy controls. Further studies are warranted to explore the potential of PAI-1 as a biomarker for diagnosing schizoaffective disorder.

Low Density Receptor-Related Protein 1 Interactions With the Extracellular Matrix: More Than Meets the Eye

The extracellular matrix (ECM) is a biological substrate composed of collagens, proteoglycans and glycoproteins that ensures proper cell migration and adhesion and keeps the cell architecture intact. The regulation of the ECM composition is a vital process strictly controlled by, among others, proteases, growth factors and adhesion receptors. As it appears, ECM remodeling is also essential for proper neuronal and glial development and the establishment of adequate synaptic signaling. Hence, disturbances in ECM functioning are often present in neurodegenerative diseases like Alzheimer’s disease. Moreover, mutations in ECM molecules are found in some forms of epilepsy and malfunctioning of ECM-related genes and pathways can be seen in, for example, cancer or ischemic injury. Low density lipoprotein receptor-related protein 1 (Lrp1) is a member of the low density lipoprotein receptor family. Lrp1 is involved not only in ligand uptake, receptor mediated endocytosis and lipoprotein transport—functions shared by low density lipoprotein receptor family members—but also regulates cell surface protease activity, controls cellular entry and binding of toxins and viruses, protects against atherosclerosis and acts on many cell signaling pathways. Given the plethora of functions, it is not surprising that Lrp1 also impacts the ECM and is involved in its remodeling. This review focuses on the role of Lrp1 and some of its major ligands on ECM function. Specifically, interactions with two Lrp1 ligands, integrins and tissue plasminogen activator are described in more detail.

Networks of blood proteins in the neuroimmunology of schizophrenia

Levels of certain circulating cytokines and related immune system molecules are consistently altered in schizophrenia and related disorders. In addition to absolute analyte levels, we sought analytes in correlation networks that could be prognostic. We analyzed baseline blood plasma samples with a Luminex platform from 72 subjects meeting criteria for a psychosis clinical high-risk syndrome; 32 subjects converted to a diagnosis of psychotic disorder within two years while 40 other subjects did not. Another comparison group included 35 unaffected subjects. Assays of 141 analytes passed early quality control. We then used an unweighted co-expression network analysis to identify highly correlated modules in each group. Overall, there was a striking loss of network complexity going from unaffected subjects to nonconverters and thence to converters (applying standard, graph-theoretic metrics). Graph differences were largely driven by proteins regulating tissue remodeling (e.g. blood-brain barrier). In more detail, certain sets of antithetical proteins were highly correlated in unaffected subjects (e.g. SERPINE1 vs MMP9), as expected in homeostasis. However, for particular protein pairs this trend was reversed in converters (e.g. SERPINE1 vs TIMP1, being synthetical inhibitors of remodeling of extracellular matrix and vasculature). Thus, some correlation signals strongly predict impending conversion to a psychotic disorder and directly suggest pharmaceutical targets.

Role of tissue-type plasminogen activator and plasminogen activator inhibitor-1 in psychological stress and depression

Major depressive disorder is a common illness worldwide, but the pathogenesis of the disorder remains incompletely understood. The tissue-type plasminogen activator-plasminogen proteolytic cascade is highly expressed in the brain regions involved in mood regulation and neuroplasticity. Accumulating evidence from animal and human studies suggests that tissue-type plasminogen activator and its chief inhibitor, plasminogen activator inhibitor-1, are related to stress reaction and depression. Furthermore, the neurotrophic hypothesis of depression postulates that compromised neurotrophin brain-derived neurotrophic factor (BDNF) function is directly involved in the pathophysiology of depression. In the brain, the proteolytic cleavage of proBDNF, a BDNF precursor, to mature BDNF through plasmin represents one mechanism that can change the direction of BDNF action. We also discuss the implications of tissue-type plasminogen activator and plasminogen activator inhibitor-1 alterations as biomarkers for major depressive disorder. Using drugs that increase tissue-type plasminogen activator or decrease plasminogen activator inhibitor-1 levels may open new avenues to develop conceptually novel therapeutic strategies for depression treatment.

MK-801-induced impairments on the trial-unique, delayed nonmatching-to-location task in rats: effects of acute sodium nitroprusside

RATIONALE

The cognitive symptoms observed in schizophrenia are not consistently alleviated by conventional antipsychotics. Following a recent pilot study, sodium nitroprusside (SNP) has been identified as a promising adjunct treatment to reduce the working memory impairments experienced by schizophrenia patients.

OBJECTIVE

The present experiments were designed to explore the effects of SNP on the highly translatable trial-unique, delayed nonmatching-to-location (TUNL) task in rats with and without acute MK-801 treatment.

METHODS

SNP (0.5, 1.0, 2.0, 4.0, and 5.0 mg/kg) and MK-801 (0.05, 0.075, and 0.1 mg/kg) were acutely administered to rats trained on the TUNL task.

RESULTS

Acute MK-801 treatment impaired TUNL task accuracy. Administration of SNP (2.0 mg/kg) with MK-801 (0.1 mg/kg) failed to rescue performance on TUNL. SNP (5.0 mg/kg) administration nearly 4 h prior to MK-801 (0.05 mg/kg) treatment had no preventative effect on performance impairments. SNP (2.0 mg/kg) improved performance on a subset of trials.

CONCLUSION

These results suggest that SNP may possess intrinsic cognitive-enhancing properties but is unable to block the effects of acute MK-801 treatment on the TUNL task. These results are inconsistent with the effectiveness of SNP as an adjunct therapy for working memory impairments in schizophrenia patients. Future studies in rodents that assess SNP as an adjunct therapy will be valuable in understanding the mechanisms underlying the effectiveness of SNP as a treatment for schizophrenia.