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

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.