The new mechanism of cognitive decline induced by hypertension: High homocysteine-mediated aberrant DNA methylation

Tectorigenin mitigates homocysteine-induced inflammation and ferroptosis in BV-2 microglial cells through promoting the SIRT1/SLC7A11 pathway

Ferroptosis and inflammation are central to the pathophysiology of hyperhomocysteinemia (HHcy)-associated neurological disorders. Tectorigenin, a natural flavonoid aglycone extracted from numerous plants, possesses antioxidant, anti-inflammatory, and neuroprotective properties. This study aimed to investigate whether tectorigenin mitigates elevated homocysteine (Hcy)-induced toxicity in BV-2 microglial cells, focusing on its effects on inflammation and ferroptosis. Cell viability, lactate dehydrogenase (LDH) release, and proliferation assays were employed to evaluate cell injury. Inflammatory cytokines levels were determined by ELISA. Ferroptosis markers, including reactive oxygen species (ROS), lipid ROS, malondialdehyde (MDA), 4-hydroxy-nonenal (4-HNE), mitochondrial membrane potential (MMP), ATP, Fe2 + content, antioxidant enzymes (superoxide dismutase [SOD] and catalase [CAT]) activities were evaluated. mRNA and protein expressions were analyzed by qRT-PCR and western blotting, respectively. Our findings revealed that tectorigenin pretreatment significantly alleviated Hcy-induced cell injury and inflammatory response in BV-2 microglial cells. Furthermore, tectorigenin pretreatment reduced lipid peroxidation, enhanced antioxidant capacity, and alleviated ferroptotic cell death in Hcy-treated cells. Importantly, ferroptosis inhibitor Fer-1 also alleviated Hcy-induced cell injury and inflammation. Mechanistically, tectorigenin pretreatment activated the SIRT1/SLC7A11 pathway, and silencing SIRT1 reversed its protective effects. Collectively, these results indicate that tectorigenin attenuates Hcy-induced microglial injury by inhibiting inflammation and ferroptosis through the activation of the SIRT1/SLC7A11 pathway.

Reduced DTI-ALPS in H-type hypertension: insights into perivascular space function

Recent studies suggest that glymphatic dysfunction plays a significant role in vascular cognitive impairment (VCI). Both hypertension and hyperhomocysteinemia are independent risk factors for VCI, and their combination is referred to as H-type hypertension (HHT). However, the impact of HHT on glymphatic function remains unclear. This study used the recently popular indirect marker, diffusion tensor imaging along the perivascular space (DTI-ALPS) to assess potential changes in glymphatic function in patients with HHT. We recruited 58 HHT patients and 50 healthy controls without hypertension, collecting clinical, cognitive, biochemical, and diffusion MRI data. Behaviorally, HHT patients scored lower on global cognitive tests compared to controls. DTI-ALPS analysis revealed a bilateral reduction in DTI-ALPS in HHT patients. Correlation analysis showed strong associations between lower DTI-ALPS values, reduced cognitive scores, and elevated homocysteine (Hcy) levels in HHT patients. Mediation analysis further indicated that DTI-ALPS largely mediates the relationship between Hcy levels and cognitive performance. These findings suggest that hypertension and elevated Hcy levels contribute to DTI-ALPS reduction, which may underlie the cognitive decline observed in HHT.

Relationship between serum homocysteine, folate and vitamin B12 levels and cognitive function in patients with drug-naive obsessive-compulsive disorder

The study aimed to investigate the correlation between Homocysteine (HCY), folate and vitamin B12 (VB12) levels and cognitive function in patients with drug-naive obsessive-compulsive disorder (OCD).Fifty patients with drug-naive OCD and 50 matched healthy controls recruited were enrolled. Subjects were cognitively assessed using The MATRICS Consensus Cognitive Battery (MCCB) scales. Serum HCY, floate, and vitamin B12 levels were collected.There was impairment in memory, attention in drug-naive OCD patients compared to the control group (P < 0.05). There were significant differences in HCY and folate levels compared to the control group (P < 0.05). SPSS mediated effects model 4 analyses showed that HCY levels mediated the relationship between Y-BCOS scores and verbal learning ability (median effect value: -0.43, 95% CI [-0.58 ~ -0.28]). Folate levels also mediated the relationship between Y-BOCS scores and verbal learning ability (median effect value: -0.11,95% CI: [-0.21 ~-0.03]). HCY levels were positively correlated with symptom severity and verbal learning ability, speed of information processing, and impaired emotion management in patients with drug-naive OCD, and folate levels may be protective against cognitive changes in patients with drug-naive OCD. OCD symptom severity together with HCY and folate levels affect cognitive function.

Homocysteine decreases VEGF, EGF, and TrkB levels and increases CCL5/RANTES in the hippocampus: Neuroprotective effects of rivastigmine and ibuprofen

Homocysteine (Hcy) is produced through methionine transmethylation. Elevated Hcy levels are termed Hyperhomocysteinemia (HHcy) and represent a risk factor for neurodegenerative conditions such as Alzheimer's disease. This study aimed to explore the impact of mild HHcy and the neuroprotective effects of ibuprofen and rivastigmine via immunohistochemical analysis of glial markers (Iba-1 and GFAP). Additionally, we assessed levels of vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), chemokine ligand 5 (CCL5/RANTES), CX3C chemokine ligand 1 (CX3CL1), and the NGF/p75NTR/tropomyosin kinase B (TrkB) pathway in the hippocampus of adult rats. Mild chronic HHcy was induced chemically in Wistar rats by subcutaneous administration of Hcy (4 mg/kg body weight) twice daily for 30 days. Rivastigmine (0.5 mg/kg) and ibuprofen (40 mg/kg) were administered intraperitoneally once daily. Results revealed elevated levels of CCL5/RANTES and reduced levels of VEGF, EGF, and TrkB in the hippocampus of HHcy-exposed rats. Rivastigmine mitigated the neurotoxic effects of HHcy by increasing TrkB and VEGF levels. Conversely, ibuprofen attenuated CCL5/RANTES levels against the neurotoxicity of HHcy, significantly reducing this chemokine's levels. HHcy-induced neurochemical impairment in the hippocampus may jeopardize neurogenesis, synapse formation, axonal transport, and inflammatory balance, leading to neurodegeneration. Treatments with rivastigmine and ibuprofen alleviated some of these detrimental effects. Reversing HHcy-induced damage through these compounds could serve as a potential neuroprotective strategy against brain damage.

Metabolome and transcriptome integration reveals cerebral cortical metabolic profiles in rats with subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a severe subtype of hemorrhagic stroke. The molecular mechanisms of its secondary brain damage remain obscure. To investigate the alterations in gene and metabolite levels following SAH, we construct the transcriptome and metabolome profiles of the rat cerebral cortex post-SAH using whole transcriptome sequencing and untargeted metabolomics assays. Transcriptomic analysis indicated that there were 982 differentially expressed genes (DEGs) and 540 differentially expressed metabolites (DEMs) between the sham group and SAH 1d, and 292 DEGs and 254 DEMs between SAH 1d and SAH 7d. Most notably, DEGs were predominantly involved in the activation of immune and inflammatory pathways, particularly the Complement and coagulation cascades, TNF signaling pathway, and NOD-like receptor signaling pathway. Metabolic analysis revealed that the metabolic pathways of Arginine and proline, Arachidonic acid, Folate biosynthesis, Pyrimidine, and Cysteine and methionine were remarkably affected after SAH. Metabolites of the above pathways are closely associated not only with immune inflammation but also with oxidative stress, endothelial cell damage, and blood-brain barrier disruption. This study provides new insights into the underlying pathologic mechanisms of secondary brain injury after SAH and further characterization of these aberrant signals could enable their application as potential therapeutic targets for SAH.

Recent progresses in natural based therapeutic materials for Alzheimer's disease

Alzheimer's disease is a neurological disorder that causes increased memory loss, mood swings, behavioral disorders, and disruptions in daily activities. Polymer scaffolds for the brain have been grown under laboratory, physiological, and pathological circumstances because of the limitations of conventional treatments for patients with central nervous system diseases. The blood-brain barrier prevents medications from entering the brain, challenging AD treatment. Numerous biomaterials such as biomolecules, polymers, inorganic metals, and metal oxide nanoparticles have been used to transport therapeutic medicines into the nervous system. Incorporating biocompatible materials that support neurogenesis through a combination of topographical, pharmacological, and mechanical stimuli has also shown promise for the transfer of cells to replenish dopaminergic neurons. Components made of naturally occurring biodegradable polymers are appropriate for the regeneration of nerve tissue. The ability of natural-based materials (biomaterials) has been shown to promote endogenous cell development after implantation. Also, strategic functionalization of polymeric nanocarriers could be employed for treating AD. In particular, nanoparticles could resolve Aβ aggregation and thus help cure Alzheimer's disease. Drug moieties can be effectively directed to the brain by utilizing nano-based systems and diverse colloidal carriers, including hydrogels and biodegradable scaffolds. Notably, early investigations employing neural stem cells have yielded promising results, further emphasizing the potential advancements in this field. Few studies have fully leveraged the combination of cells with cutting-edge biomaterials. This study provides a comprehensive overview of prior research, highlighting the pivotal role of biomaterials as sophisticated drug carriers. It delves into various intelligent drug delivery systems, encompassing pH and thermo-triggered mechanisms, polymeric and lipid carriers, inorganic nanoparticles, and other vectors. The discussion synthesizes existing knowledge and underscores the transformative impact of these biomaterials in devising innovative strategies, augmenting current therapeutic methodologies, and shaping new paradigms in the realm of Alzheimer's disease treatment.

Advances in the role of epigenetics in homocysteine-related diseases

Homocysteine has a wide range of biological effects. However, the specific molecular mechanism of its pathogenicity is still unclear. The diseases induced by hyperhomocysteinemia (HHcy) are called homocysteine-related diseases. Clinical treatment of HHcy is mainly through folic acid and B-complex vitamins, which are not effective in reducing the associated end point events. Epigenetics is the alteration of heritable genes caused by DNA methylation, histone modification, noncoding RNAs and chromatin remodeling without altering the DNA sequence. In recent years the role of epigenetics in homocysteine-associated diseases has been gradually discovered. This article summarizes the latest evidence on the role of epigenetics in HHcy, providing new directions for its prevention and treatment.

Integrating transcriptomics and metabolomics to analyze the mechanism of hypertension-induced hippocampal injury

Objective

Hypertension is a public health challenge worldwide due to its high prevalence and multiple complications. Hypertension-induced damage to the hippocampus leads to behavioral changes and various brain diseases. Despite the multifaceted effects of hypertension on the hippocampus, the mechanisms underlying hippocampal lesions are still unclear.

Methods

The 32-week-old spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats were selected as the study subjects. Behavioral experiments such as an open field test (OFT), an elevated plus maze (EPM) test, and the Morris water maze (MWM) test were performed to show the behavioral characteristics of the rats. A comprehensive transcriptomic and metabolomic analysis was performed to understand the changes in the hippocampus at the metabolic and genetic levels.

Results

Behavioral tests showed that, compared to WKY rats, SHR showed not only reduced memory capacity but more hyperactive and impulsive behavior. In addition, transcriptomic analysis screened for 103 differentially expressed genes. Metabolomic analysis screened 56 metabolites with significant differences, including various amino acids and their related metabolites.

Conclusion

Comprehensive analysis showed that hypertension-induced hippocampal lesions are closely associated with differential metabolites and differential genes detected in this study. The results provide a basis for analyzing the mechanisms of hypertension-induced hippocampal damage.

POLYMORPHISM OF ACE AND AT2R1 GENES AS A GENETIC BACKGROUND FOR DIFFERENT TYPES OF ENCEPHALOPATHIES

OBJECTIVE

The aim: To study the prevalence of ACE I/D and AT2R1 A1166C gene polymorphisms in patients with CTE, SVD, AIE, and PIE and to assess the influence of the presence of a particular genotype of the studied genes on the occurrence and/or progression of encephalopathies.

PATIENTS AND METHODS

Materials and methods: A total of 96 patients with encephalopathies of various genesis (chronic traumatic encephalopathy (CTE) n=26; chronic alcohol-induced encephalopathy (AIE) n=26; microvascular ischemic disease of the brain (or cerebral small vessel disease, (SVD)) n=18; post-infectious encephalopathy (PIE) n=26) were involved in the study. The molecular genetic study was performed in the molecular genetics laboratory of the State Institution «Reference Center for Molecular Diagnostics of the Ministry of Health of Ukraine», Kyiv. Statistical processing of the results was performed using the STATISTICA 10.0 program.

RESULTS

Results: In patients with various types of encephalopathies, probable changes in the frequency distribution of genotypes of polymorphic variants I/D of the ACE gene were established (11.11% vs. 33.33% - carriers of the I/I genotype, 27.78% vs. 50.00% - carriers of the I/D genotype and 61.11% vs. 16.67% - carriers of the D/D genotype) and A1166C of the AT2R1 gene (22.22% vs. 66.67% - carriers of the A/A genotype, 50.00% vs. 25.00% - carriers A/C genotype, 27.78% versus 8.33% - carriers of the C/C genotype) compared to individuals of the control group only in patients with SVD. The presence of the D allele and the D/D genotype of the ACE gene is associated with a statistically significant increase in the risk of SVD development and progression (respectively, 4.2 times (95% CI (1.39-12.72)) and 7.9 (95% CI ( 1.31-47.05)) times). A similar trend was established for the carrier of the C allele of the A1166C polymorphic variant of the AT2R1 gene in patients with SVD: a 4.3-fold increase in the risk of development and progression (95% CI (1.30-13.86). In addition, there is a probable dependence between carrier genotype A/C of the AT2R1 gene and increased risk of PIE and AIE by 4.8 and 5.7 times, respectively.

CONCLUSION

Conclusions: Therefore, results suggest the reasonability to include the I/D of the ACE gene polymorphism investigation in the genetic panel of encephalopathies.