Decreased Prolidase Activity in Patients with Posttraumatic Stress Disorder

Electroconvulsive Therapy and Extracellular Matrix Glycoproteins in Patients with Depressive Episodes

Background

The brain extracellular matrix (ECM) is composed of glycoproteins deriving from the cell membrane and joining into nets called perineuronal nets (PNNs). The ECM glycoproteins limit neuroplasticity, cell proliferation, and differentiation. Electroconvulsive therapy (ECT) is provided by electrical currents that may alter several cascades and biophysical effects. ECM conformation might be influenced by the effects of ECT.

Methods

Patients with depressive disorders (n = 23) and healthy control subjects (n = 21) were enrolled. Serum levels of the ECM glycoproteins versican, brevican, neurocan, phosphocan and tenascin C were measured with enzyme-linked immunosorbent assay. Serum samples were collected from the patients in the patient group at 3 time points: before ECT, 30 min after the first session, and 30 min after the seventh session.

Results

There was a significant difference in tenascin C levels (P = .001) between the groups. No other significant difference was observed. Serum levels of the measured ECM glycoproteins and prolidase activity did not differ in the depression group after the administration of ECT.

Conclusions

Our results did not support the claim suggesting a possible mechanism for modulation of ECM glycoproteins by ECT. Serum levels may not necessarily reflect conformational changes in the ECM. Further studies are needed to investigate the effects of ECT on ECM glycoproteins. Modulation of the ECM may provide a new window suggesting improvement in treatments.

Evaluation of the Oxidative Stress Level and Serum Prolidase Activity in Patients with Sleep Bruxism

Aims and Objective:

Sleep bruxism is a complicated disease, and its cause remains controversial. If the etiology of bruxism is resolved, the treatment can be adjusted to the prevailing aetiological factor. Thus, the aim of this study was to evaluate the oxidative stress level and serum prolidase activity in patients with sleep bruxism.

Materials and Methods:

Seventy healthy subjects and 51 patients with sleep bruxism were included in this study, and blood samples from all patients were collected. Serum samples were analyzed for total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), and prolidase activity.

Results:

The prolidase, TOS, and OSI levels were significantly higher in patients with bruxism than in the healthy controls (p = 0.001, p = 0.001, p = 0.001, respectively). The TAS level was significantly lower in bruxism patients than in healthy controls (p = 0.003).

Conclusion:

The increased TOS, OSI, and prolidase levels and decreased TAS levels could be assumed to result in oxidative injury in patients with sleep bruxism. However, the study could not determine whether oxidative imbalance and increased serum prolidase levels could be a cause or a result of bruxism.

Metabolomics in posttraumatic stress disorder: Untargeted metabolomic analysis of plasma samples from Croatian war veterans

Posttraumatic stress disorder (PTSD) is a severe, multifactorial and debilitating neuropsychiatric disorder, which can develop in a subset of individuals as a result of the exposure to severe stress or trauma. Such traumatic experiences have a major impact on molecular, biochemical and cellular systems, causing psychological and somatic alterations that affect the whole organism. Although the etiology of PTSD is still unclear, it seems to involve complex interaction between various biological genetic and environmental factors. Metabolomics, as one of the rapidly developing "omics" techniques, might be a useful tool for determining altered metabolic pathways and stress-related metabolites as new potential biomarkers of PTSD. The aim of our study was to identify metabolites whose altered levels allow us to differentiate between patients with PTSD and healthy control individuals. The study included two cohorts. The first, exploratory, group included 50 Croatian veterans with PTSD and 50 healthy control subjects, whereas a validation group consisted of 52 veterans with PTSD and 52 control subjects. The metabolomic analysis of plasma samples was conducted using liquid chromatography coupled with mass spectrometry (LC-MS), as well as gas chromatography coupled with mass spectrometry (GC-MS). The LC-MS analysis determined significantly different levels of two glycerophospholipids, PE(18:1/0:0) and PC(18:1/0:0), between control subjects and PTSD patients in both cohorts. The altered metabolites might play a role in multiple cellular processes, including inflammation, mitochondrial dysfunction, membrane breakdown, oxidative stress and neurotoxicity, which could be associated with PTSD pathogenesis.

PROLIDASE: A Review from Discovery to its Role in Health and Disease

Prolidase (peptidase D), encoded by the PEPD gene, is a ubiquitously expressed cytosolic metalloproteinase, the only enzyme capable of cleaving imidodipeptides containing C-terminal proline or hydroxyproline. Prolidase catalyzes the rate-limiting step during collagen recycling and is essential in protein metabolism, collagen turnover, and matrix remodeling. Prolidase, therefore plays a crucial role in several physiological processes such as wound healing, inflammation, angiogenesis, cell proliferation, and carcinogenesis. Accordingly, mutations leading to loss of prolidase catalytic activity result in prolidase deficiency a rare autosomal recessive metabolic disorder characterized by defective wound healing. In addition, alterations in prolidase enzyme activity have been documented in numerous pathological conditions, making prolidase a useful biochemical marker to measure disease severity. Furthermore, recent studies underscore the importance of a non-enzymatic role of prolidase in cell regulation and infectious disease. This review aims to provide comprehensive information on prolidase, from its discovery to its role in health and disease, while addressing the current knowledge gaps.