The protective effects of memantine against inflammation and impairment of endothelial tube formation induced by oxygen-glucose deprivation/reperfusion

NMDA Receptor Antagonist Memantine Ameliorates Experimental Autoimmune Encephalomyelitis in Aged Rats

Aging is closely related to the main aspects of multiple sclerosis (MS). The average age of the MS population is increasing and the number of elderly MS patients is expected to increase. In addition to neurons, N-methyl-D-aspartate receptors (NMDARs) are also expressed on non-neuronal cells, such as immune cells. The aim of this study was to investigate the role of NMDARs in experimental autoimmune encephalomyelitis (EAE) in young and aged rats. Memantine, a non-competitive NMDAR antagonist, was administered to young and aged Dark Agouti rats from day 7 after immunization. Antagonizing NMDARs had a more favourable effect on clinical disease, reactivation, and apoptosis of CD4+ T cells in the target organ of aged EAE rats. The expression of the fractalkine receptor CX3CR1 was increased in memantine-treated rats, but to a greater extent in aged rats. Additionally, memantine increased Nrf2 and Nrf2-regulated enzymes' mRNA expression in brain tissue. The concentrations of superoxide anion radicals, malondialdehyde, and advanced oxidation protein products in brain tissue were consistent with previous results. Overall, our results suggest that NMDARs play a more important role in the pathogenesis of EAE in aged than in young rats.

Aminoadamantanes: from treatment of Parkinson's and Alzheimer's disease to symptom amelioration of long COVID-19 syndrome?

INTRODUCTION

The aminoadamantanes amantadine and memantine are well known. They mainly act as N-methyl-D-aspartate antagonists.

AREAS COVERED

The antiviral drug amantadine moderately ameliorates impaired motor behavior in patients with Parkinson's disease. Memantine provides beneficial effects on memory function in patients with advanced Alzheimer's disease already treated with acetylcholine esterase inhibitors. Both compounds counteract impaired monoamine neurotransmission with associated symptoms, such as depression. They improve vigilance, lack of attention and concentration, fatigue syndromes according to clinical findings in patients with chronic neurodegenerative processes. Their extrasynaptic N-methyl-D-Aspartate receptor blockade weakens a prolonged influx of Ca²⁺ ions as the main responsible components of neuronal excitotoxicity. This causes neuronal dying and associated functional deficits.

EXPERT OPINION

We suggest aminoadamantanes as future therapies for amelioration of short- and long-term consequences of a COVID 19 infection. Particularly the extended-release amantadine formulations will be suitable. They showed better clinical efficacy compared with the conventional available compounds. Amantadine may particularly be suitable for amelioration of fatigue or chronic exhaustion, memantine for improvement of cognitive deficits. Clinical research in patients, who are affected by the short- and long-term consequences of a COVID 19 infection, is warranted to confirm these still hypothetical putative beneficial effects of aminoadamantanes.

[Pathogenetic therapy of cognitive impairment: results of a multicenter placebo-controlled clinical trial of the efficacy and safety of Miladean]

OBJECTIVE

Evaluation of the efficacy and safety of the use of the drug Miladean in the treatment of patients with cognitive disorders (CDs) of vascular genesis.

MATERIAL AND METHODS

In during the double-blind multicenter prospective randomized placebo-controlled phase III clinical trial, 300 patients with CDs and chronic cerebral ischemia were randomized into 3 groups: group 1 (n=100) received Miladean (daily dose: memantine 10 mg + melatonin 6 mg), group 2 (n=101) - memantine (10 mg/day), group 3 - placebo (n=99) for 8 weeks. The dynamics of the overall score (the primary criterion of effectiveness) and the proportion of patients with improvement on the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog), the dynamics of visual-spatial orientation disorders (Benton test), sleep quality (Pittsburgh Sleep Quality Index scale) and the safety of therapy were evaluated.

RESULTS

Miladean demonstrated efficacy in the treatment of CDs: a statistically and clinically significant decrease in the overall score on the ADAS-Sod scale was shown (by 6.1 versus 4.7 and 3.5 points in the 2nd (p=0.009) and 3rd (p<0.05) groups) and an increase in the proportion of patients (96.9%) with clinically and statistically a significant improvement compared to the 2nd and 3rd groups (p=0.019 and p<0.001 respectively). Miladean significantly improved the performance in the Benton test (1.20±1.66 vs. 0.64±1.69 points in group 3, p=0.026) and sleep quality (84.7% of patients with CDs), compared to placebo (63.9%) and memantine (64.3%) (p=0.002 in both cases). Miladean was well tolerated, there were no cases of interaction with basic therapy drugs.

CONCLUSION

The combination of many different pathogenetic effects of Miladean suggests that it has the ability to slow down the rate of progression of CDs and stabilize the condition of patients. The unique combination of active substances in Miladean has been proven to be effective and safe in the treatment of patients with CDs.

Nrf2-Mediated Dichotomy in the Vascular System: Mechanistic and Therapeutic Perspective

Nuclear factor-erythroid 2-related factor 2 (Nrf2), a transcription factor, controls the expression of more than 1000 genes that can be clustered into different categories with distinct functions ranging from redox balance and metabolism to protein quality control in the cell. The biological consequence of Nrf2 activation can be either protective or detrimental in a context-dependent manner. In the cardiovascular system, most studies have focused on the protective properties of Nrf2, mainly as a key transcription factor of antioxidant defense. However, emerging evidence revealed an unexpected role of Nrf2 in mediating cardiovascular maladaptive remodeling and dysfunction in certain disease settings. Herein we review the role of Nrf2 in cardiovascular diseases with a focus on vascular disease. We discuss the negative effect of Nrf2 on the vasculature as well as the potential underlying mechanisms. We also discuss the clinical relevance of targeting Nrf2 pathways for the treatment of cardiovascular and other diseases.

Effects and mechanisms of 6-hydroxykaempferol 3,6-di-O-glucoside-7-O-glucuronide from Safflower on endothelial injury in vitro and on thrombosis in vivo

Background: The florets of Carthamus tinctorius L. (Safflower) is an important traditional medicine for promoting blood circulation and removing blood stasis. However, its bioactive compounds and mechanism of action need further clarification.

Objective: This study aims to investigate the effect and possible mechanism of 6-hydroxykaempferol 3,6-di-O-glucoside-7-O-glucuronide (HGG) from Safflower on endothelial injury in vitro, and to verify its anti-thrombotic activity in vivo.

Methods: The endothelial injury on human umbilical vein endothelial cells (HUVECs) was induced by oxygen-glucose deprivation followed by reoxygenation (OGD/R). The effect of HGG on the proliferation of HUVECs under OGD/R was evaluated by MTT, LDH release, Hoechst-33342 staining, and Annexin V-FITC apoptosis assay. RNA-seq, RT-qPCR, Enzyme-linked immunosorbent assay and Western blot experiments were performed to uncover the molecular mechanism. The anti-thrombotic effect of HGG in vivo was evaluated using phenylhydrazine (PHZ)-induced zebrafish thrombosis model.

Results: HGG significantly protected OGD/R induced endothelial injury, and decreased HUVECs apoptosis by regulating expressions of hypoxia inducible factor-1 alpha (HIF-1α) and nuclear factor kappa B (NF-κB) at both transcriptome and protein levels. Moreover, HGG reversed the mRNA expression of pro-inflammatory cytokines including IL-1β, IL-6, and TNF-α, and reduced the release of IL-6 after OGD/R. In addition, HGG exhibited protective effects against PHZ-induced zebrafish thrombosis and improved blood circulation.

Conclusion: HGG regulates the expression of HIF-1α and NF-κB, protects OGD/R induced endothelial dysfunction in vitro and has anti-thrombotic activity in PHZ-induced thrombosis in vivo.

NMDA receptor antagonists reduce amyloid-β deposition by modulating calpain-1 signaling and autophagy, rescuing cognitive impairment in 5XFAD mice

Overstimulation of N-methyl-d-aspartate receptors (NMDARs) is the leading cause of brain excitotoxicity and often contributes to neurodegenerative diseases such as Alzheimer’s Disease (AD), the most common form of dementia. This study aimed to evaluate a new NMDA receptor antagonist (UB-ALT-EV) and memantine in 6-month-old female 5XFAD mice that were exposed orally to a chronic low-dose treatment. Behavioral and cognitive tests confirmed better cognitive performance in both treated groups. Calcium-dependent protein calpain-1 reduction was found after UB-ALT-EV treatment but not after memantine. Changes in spectrin breakdown products (SBDP) and the p25/p35 ratio confirmed diminished calpain-1 activity. Amyloid β (Aβ) production and deposition was evaluated in 5XFAD mice and demonstrated a robust effect of NMDAR antagonists on reducing Aβ deposition and the number and size of Thioflavin-S positive plaques. Furthermore, glycogen synthase kinase 3β (GSK3β) active form and phosphorylated tau (AT8) levels were diminished after UB-ALT-EV treatment, revealing tau pathology improvement. Because calpain-1 is involved in autophagy activation, autophagic proteins were studied. Strikingly, results showed changes in the protein levels of unc-51-like kinase (ULK-1), beclin-1, microtubule-associated protein 1A/1B-light chain 3(LC3B-II)/LC3B-I ratio, and lysosomal-associated membrane protein 1 (LAMP-1) after NMDAR antagonist treatments, suggesting an accumulation of autophagolysosomes in 5XFAD mice, reversed by UB-ALT-EV. Likewise, treatment with UB-ALT-EV recovered a WT mice profile in apoptosis markers Bcl-2, Bax, and caspase-3. In conclusion, our results revealed the potential neuroprotective effect of UB-ALT-EV by attenuating NMDA-mediated apoptosis and reducing Aβ deposition and deposition jointly with the autophagy rescue to finally reduce cognitive alterations in a mice model of familial AD.

Memantine Alleviates Acute Lung Injury Via Inhibiting Macrophage Pyroptosis

ABSTRACT

Acute lung injury (ALI) is caused by direct pulmonary insults and indirect systemic inflammatory responses that result from conditions such as sepsis and trauma. Alveolar macrophages are the main and critical leukocytes in the airspace, and through the synthesis and release of various inflammatory mediators critically influence the development of ALI following infection and non-infectious stimuli. There is increasing recognition that inflammation and cell death reciprocally affect each other, which forms an auto-amplification loop of these two factors, and in turn, exaggerates inflammation. Therefore, pharmacological manipulation of alveolar macrophage death signals may serve as a logical therapeutic strategy for ALI. In this study, we demonstrate that memantine, a N-methyl-D-aspartic acid receptor (NMDAR) antagonist, through suppressing Ca2+ influx and subsequent ASC oligomerization inhibits macrophage Nlrp3 inflammasome activation and pyroptosis, therefore, alleviates ALI in septic mice. This finding explores a novel application of memantine, an FDA already approved medication, in the treatment of ALI, which is currently lacking effective therapy.

Beneficial effects of memantine on ischemia/reperfusion injury following torsion/detorsion induced testicular damage in rats: Improvement in histological and biochemical parameters

INTRODUCTION

Testicular torsion is a common urologic emergency and one of the causes of infertility in males. Hence, prompt diagnosis and treatment are important to prevent testicular damages. It has been reported that memantine, a drug for Alzheimer's disease has anti-oxidative role against cerebral ischemic stroke and cardiac ischemia reperfusion.

OBJECTIVE

In this experimental study, the effects of memantine on a testicular torsion injury in adolescent rat testis after ischemia/reperfusion (I/R) were evaluated.

STUDY DESIGN

Thirty-six adolescent rats were divided into three groups with 12 rats per group including sham-operated, T/D (torsion/detorsion) + vehicle, and T/D + memantine (10 mg/kg). Testicular torsion was induced for 2 h by rotating right testis 720⁰ in the clockwise direction. In treated group 30 min before detorsion, a single intraperitoneal dose of memantine was administered. After 4 h of reperfusion, orchiectomy was conducted and Histopathological and biochemical evaluations of testicular tissue samples were performed.

RESULTS

The malondialdehyde level in the T/D group was significantly greater than in the sham operated group. Moreover, the testicular malondialdehyde values in the T/D + memantine group were significantly lower than in the T/D group. Also, significant decreases occurred in catalase and superoxide dismutase activities in the T/D group compared with sham operated group. These values were significantly greater in the memantine group than in the T/D group. Furthermore, after induction of T/D, histopathological evaluations also revealed severe testicular damages which were improved by memantine administration.

DISCUSSION

Memantine prevented increases in oxidative stress markers and reductions of antioxidants during I/R injury in the current study. Subsequently the histologic injury was reduced in rats treated with memantine. The antioxidant characteristics of memantine and its protective effects have been shown in our study.

CONCLUSION

These results suggest that administration of memantine before detorsion prevents I/R cellular damage in testicular torsion. This drug probably acts through reduction of reactive oxygen species and support antioxidant enzyme systems.