The Role of Opioid Receptor Antagonists in Regulation of Blood Pressure and T-Cell Activation in Mice Selected for High Analgesia Induced by Swim Stress

Opioid peptides and their G protein-coupled receptors are important regulators within the cardiovascular system, implicated in the modulation of both heart and vascular functions. It is known that naloxone-an opioid antagonist-may exert a hypertensive effect. Recent experimental and clinical evidence supports the important role of inflammatory mechanisms in hypertension. Since opioids may play a role in the regulation of both blood pressure and immune response, we studied these two processes in our model. We aimed to evaluate the effect of selective and non-selective opioid receptor antagonists on blood pressure and T-cell activation in a mouse model of high swim stress-induced analgesia. Blood pressure was measured before and during the infusion of opioid receptor antagonists using a non-invasive tail-cuff measurement system. To assess the activation of T-cells, flow cytometry was used. We discovered that the non-selective antagonism of the opioid system by naloxone caused a significant elevation of blood pressure. The selective antagonism of μ and κ but not δ opioid receptors significantly increased systolic blood pressure. Subsequently, a brief characterization of T-cell subsets was performed. We found that the blockade of μ and δ receptors is associated with the increased expression of CD69 on CD4 T-cells. Moreover, we observed an increase in the central memory CD4 and central memory CD8 T-cell populations after the δ opioid receptor blockade. The antagonism of the μ opioid receptor increased the CD8 effector and central memory T-cell populations.

Mouse CCL9 Chemokine Acts as Tumor Suppressor in a Murine Model of Colon Cancer

Colorectal cancer is the third most frequently diagnosed cancer in the world. Despite extensive studies and apparent progress in modern strategies for disease control, the treatment options are still not sufficient and effective, mostly due to frequently encountered resistance to immunotherapy of colon cancer patients in common clinical practice. In our study, we aimed to uncover the CCL9 chemokine action employing the murine model of colon cancer to seek new, potential molecular targets that could be promising in the development of colon cancer therapy. Mouse CT26.CL25 colon cancer cell line was used for introducing lentivirus-mediated CCL9 overexpression. The blank control cell line contained an empty vector, while the cell line marked as CCL9+ carried the CCL9-overexpressing vector. Next, cancer cells with empty vector (control) or CCL9-overexpressing cells were injected subcutaneously, and the growing tumors were measured within 2 weeks. Surprisingly, CCL9 contributed to a decline in tumor growth in vivo but had no effect on CT26.CL25 cell proliferation or migration in vitro. Microarray analysis of the collected tumor tissues revealed upregulation of the immune system-related genes in the CCL9 group. Obtained results suggest that CCL9 reveals its anti-proliferative functions by interplay with host immune cells and mediators that were absent in the isolated, in vitro system. Under specific study conditions, we determined unknown features of the murine CCL9 that have so far bee reported to be predominantly pro-oncogenic.

Perceived stress level among patients with chronic illness during covid pandemia

Introduction

The emergence of SARS-CoV-2 has enormously impacted healthcare systems around the world. Both patients and health care professionals have been subjected to a novel stressor which affects their everyday life and functioning. This issue is especially important to patients suffering from chronic diseases which had already been exposed to a psychological strain related to their primary diagnosis. As chronically ill patients are depending on the availability of a specific treatment i.e. in need of specific healthcare facilities and have more reasons to worry about their future and hence be more prone to suffer adverse psychological consequences than the general population.

Objectives

In this study we aimed to examine whether the psychological results of the pandemic affect chronically ill and whether the specific illness and other demographic factors account for any changes in perceived stress levels.

Methods

An online questionnaire has been distributed to 4 groups (n=369): 92 psoriasis patients, 73 dialysis patients, 100 patients after kidney transplantation and 104 multiple sclerosis patients. The study was conducted during the pandemic in Poland (June-July 2020). Perceived stress levels were measured by the Perceived Stress Scale (PSS).

Results

The preliminary results suggest elevated perceived stress levels among the studied groups. As the data are currently under statistical evaluation specific statistical conclusions are to be expected in November 2020.

Conclusions

As the described study was conducted during the SARS-CoV-2 pandemic in Poland, it stands to reason that the epidemiological situation affected the levels of perceived stress among chronically ill patients.

Loss of Brain-Derived Neurotrophic Factor (BDNF) Resulting From Congenital- Or Mild Traumatic Brain Injury-Induced Blood-Brain Barrier Disruption Correlates With Depressive-Like Behaviour

Brain-derived neurotrophic factor (BDNF) plays an important role in processes associated with neuroplasticity and neuroprotection. Evidence suggests that decreased BDNF levels in the central nervous system (CNS) represent a mechanism underlying the development of mood disorders. We hypothesize that both congenital and traumatic brain injury (mTBI)-induced blood-brain barrier (BBB) breakdown are responsible for brain BDNF depletion that contributes to the development of depressive-like symptoms. We employed a mouse model of innate differences in BBB integrity with high (HA) and low (LA) permeability. Depressive-like behaviours were determined under chronic mild stress (CMS) conditions or following mTBI using the tail suspension test (TST). Microvascular leakage of the BBB was evaluated using the Evans Blue Dye (EBD) extravasation method. BDNF concentrations in the brain and plasma were measured using the ELISA. Control HA mice with congenitally high BBB permeability showed exacerbated depressive-like behaviours compared with LA mice. In LA mice, with normal BBB function, mTBI, but not CMS, facilitated depressive-like behaviours, which correlated with enhanced BDNF efflux from the brain. In addition, mTBI triggered upregulation of the Bdnf gene in LA mice to compensate for BDNF loss. No alterations in BDNF levels were observed in mTBI and CMS-exposed HA mice. Moreover, CMS did not induce BBB damage or affect depressive-like behaviours in HA mice despite downregulating Bdnf gene expression. To conclude, BDNF efflux through the mTBI-disrupted BBB is strongly linked to the development of depressive-like behaviours, while the depressive phenotype in mice with congenital BBB dysfunction is independent of BDNF leakage.

Relationship between Down-Regulation of Copper-Related Genes and Decreased Ferroportin Protein Level in the Duodenum of Iron-Deficient Piglets

In mammals, 2 × 10¹² red blood cells (RBCs) are produced every day in the bone marrow to ensure a constant supply of iron to maintain effective erythropoiesis. Impaired iron absorption in the duodenum and inefficient iron reutilization from senescent RBCs by macrophages contribute to the development of anemia. Ferroportin (Fpn), the only known cellular iron exporter, as well as hephaestin (Heph) and ceruloplasmin, two copper-dependent ferroxidases involved in the above-mentioned processes, are key elements of the interaction between copper and iron metabolisms. Crosslinks between these metals have been known for many years, but metabolic effects of one on the other have not been elucidated to date. Neonatal iron deficiency anemia in piglets provides an interesting model for studying this interplay. In duodenal enterocytes of young anemic piglets, we identified iron deposits and demonstrated increased expression of ferritin with a concomitant decline in both Fpn and Heph expression. We postulated that the underlying mechanism involves changes in copper distribution within enterocytes as a result of decreased expression of the copper transporter—Atp7b. Obtained results strongly suggest that regulation of iron absorption within enterocytes is based on the interaction between proteins of copper and iron metabolisms and outcompetes systemic regulation.

Ethnopharmacological Applications Targeting Alcohol Abuse: Overview and Outlook

Excessive alcohol consumption is the cause of several diseases and thus is of a major concern for society. Worldwide alcohol consumption has increased by many folds over the past decades. This urgently calls for intervention and relapse counteract measures. Modern pharmacological solutions induce complete alcohol self-restraint and prevent relapse, but they have many side effects. Natural products are most promising as they cause fewer adverse effects. Here we discuss in detail the medicinal plants used in various traditional/folklore medicine systems for targeting alcohol abuse. We also comprehensively describe preclinical and clinical studies done on some of these plants along with the possible mechanisms of action.

Bidirectional selection for high and low stress-induced analgesia affects G-protein activity

Mice selected for high (HA) and low (LA) swim stress-induced analgesia (SSIA) are a unique model for studying the genetic background of this phenomenon. HA and LA miceshow substantial differences in the magnitude of the antinociceptive response to stress and when treated with exogenous opioids. However, the direct cause underplaying this distinctive feature has not yet been identified. The current study was designed to investigate the possibility that disturbances in G-protein signaling could explain the divergent response to opioid agonists. Supraspinal and spinal opioid sensitivity was assessed in vivo with intraperitoneal morphine and subsequent thermal stimulus exposure. The level of opioid receptor-mediated G-protein activation was investigated by means of DAMGO and morphine-stimulated [³⁵S]GTPγS assay in the brain and spinal cord homogenates from HA and LA mice. Morphine (3-249 μmol/kg, i.p) was over 6 - and 3 - times more potent in HA than LA mice in the hot plate and tail-flick assays, respectively. Additionally, HA mice showed elevated β - endorphin levels in the brain. Enhanced efficacy of agonist-stimulated [³⁵S]GTPγS binding was detected in opioid receptor-rich limbic regions of HA mice like the hypothalamus and hippocampus. Increased G-protein activity also emerged in the thalamus, periaqueductal gray matter and prefrontal cortex. In conclusion, the magnitude of the antinociceptive response to opioids in HA and LA mice is correlated with alterations in G-protein activation in brain regions responsible for integration and descending modulation of nociceptive information as well as at sites governing the emotional response to stressful stimuli.