Therapeutic Effects of Hydrogen Gas Inhalation on Trimethyltin-Induced Neurotoxicity and Cognitive Impairment in the C57BL/6 Mice Model

Oxidative stress (OS) is one of the causative factors in the pathogenesis of various neurodegenerative diseases, including Alzheimer’s disease (AD) and cognitive dysfunction. In the present study, we investigated the effects of hydrogen (H2) gas inhalation in trimethyltin (TMT)-induced neurotoxicity and cognitive dysfunction in the C57BL/6 mice. First, mice were divided into the following groups: mice without TMT injection (NC), TMT-only injection group (TMT only), TMT injection + lithium chloride-treated group as a positive control (PC), and TMT injection + 2% H2 inhalation-treated group (H2). The TMT injection groups were administered a single dosage of intraperitoneal TMT injection (2.6 mg/kg body weight) and the H2 group was treated with 2% H2 for 30 min once a day for four weeks. Additionally, a behavioral test was performed with Y-maze to test the cognitive abilities of the mice. Furthermore, multiple OS- and AD-related biomarkers such as reactive oxygen species (ROS), nitric oxide (NO), calcium (Ca2+), malondialdehyde (MDA), glutathione peroxidase (GPx), catalase, inflammatory cytokines, apolipoprotein E (Apo-E), amyloid β (Aβ)-40, phospho-tau (p-tau), Bcl-2, and Bcl-2- associated X (Bax) were investigated in the blood and brain. Our results demonstrated that TMT exposure alters seizure and spatial recognition memory. However, after H2 treatment, memory deficits were ameliorated. H2 treatment also decreased AD-related biomarkers, such as Apo-E, Aβ-40, p-tau, and Bax and OS markers such as ROS, NO, Ca2+, and MDA in both serum and brain. In contrast, catalase and GPx activities were significantly increased in the TMT-only group and decreased after H2 gas treatment in serum and brain. In addition, inflammatory cytokines such as granulocyte colony-stimulating factors (G-CSF), interleukin (IL)-6, and tumor necrosis factor alpha (TNF-α) were found to be significantly decreased after H2 treatment in both serum and brain lysates. In contrast, Bcl-2 and vascular endothelial growth factor (VEGF) expression levels were found to be enhanced after H2 treatment. Taken together, our results demonstrated that 2% H2 gas inhalation in TMT-treated mice exhibits memory enhancing activity and decreases the AD, OS, and inflammatory-related markers. Therefore, H2 might be a candidate for repairing neurodegenerative diseases with cognitive dysfunction. However, further mechanistic studies are needed to fully clarify the effects of H2 inhalation on TMT-induced neurotoxicity and cognitive dysfunction.

Liver Health and Dementia in an Italian Older Population: Findings From the Salus in Apulia Study

Objectives: Non-alcoholic fatty liver disease (NAFLD) currently affects a quarter of the global population. Systemic inflammation, metabolic syndrome, and coronary artery disease, all conditions associated with NAFLD, have also been related to cognitive dysfunction in older age. The present study aimed to investigate the relationship between NAFLD risk and a dementia diagnosis in a large population-based sample aged > 65 years.Methods: We selected 1,542 participants (723 men) from the Salus in Apulia Study. To assess the risk of fat distribution in the liver, we used the Fatty Liver Index (FLI). Dementia was diagnosed according to the American Psychiatric Association criteria (DSM-5).Results: The overall prevalence of dementia was 8.5% [95% confidence interval (CI): 7–10%]. Subjects with dementia were older [effect size (ES): −0.89, 95% CI: −1.07 to −0.70], had a lower level of education (ES:0.88, 95% CI:0.69–1.06), higher levels of gamma-glutamyl transferase (ES: −0.21, 95% CI: −0.39 to −0.03), lower levels of total cholesterol (ES: −0.24, 95% CI: −0.42 to −0.06) and low-density lipoprotein cholesterol (ES: −0.20, 95% CI: −0.38 to 0.02), and a higher FLI (ES: −0.22, 95% CI: −0.39 to −0.04). In the logistic regression model adjusted for age, sex, education, hypertension, diabetes mellitus, alcohol consumption, smoking habits, stroke, cholesterol, and Apo-E, a dementia diagnosis was positively associated with FLI > 60 [odds ratio (OR):1.81; standard error (SE): 0.53; 95% CI: 1.02–3.21].Conclusion: Our findings suggested that an increased NAFLD risk may be associated to dementia and cognitive decline in older age. Considering the high NAFLD prevalence, the possible adverse disease effects on cognitive performance pose a health problem with significant social and economic implications.

The Beneficial Effects of Astaxanthin on Glucose Metabolism and Modified Low-Density Lipoprotein in Healthy Volunteers and Subjects with Prediabetes

Astaxanthin (ASTX) is an antioxidant agent. Recently, its use has been focused on the prevention of diabetes and atherosclerosis. We examined the effects of astaxanthin supplementation for 12 weeks on glucose metabolism, glycemic control, insulin sensitivity, lipid profiles and anthropometric indices in healthy volunteers including subjects with prediabetes with a randomized, placebo-controlled trial. Methods: We enrolled 53 subjects who met our inclusion criteria and administered them with 12 mg astaxanthin or a placebo once daily for 12 weeks. Subsequently, their HbA1c levels, lipid profiles and biochemical parameters were determined. The participants also underwent a 75 g oral glucose tolerance test (OGTT), vascular endothelial function test and measurement of the visceral fat area. Results: After astaxanthin supplementation for 12 weeks, glucose levels after 120 min in a 75 g OGTT significantly decreased compared to those before supplementation. Furthermore, the levels of HbA1c (5.64 ± 0.33 vs. 5.57 ± 0.39%, p < 0.05), apo E (4.43 ± 1.29 vs. 4.13 ± 1.24 mg/dL, p < 0.05) and malondialdehyde-modified low-density lipoprotein (87.3 ± 28.6 vs. 76.3 ± 24.6 U/L, p < 0.05) were also reduced, whereas total cholesterol (TC), triglyceride (TG) and high-density lipoprotein-C (HDL-C) levels were unaltered. The Matuda index, which is one of the parameters of insulin resistance, was improved in the ASTX group compared to that before supplementation. Conclusions: our results suggest that ASTX may have preventive effects against diabetes and atherosclerosis and may be a novel complementary treatment option for the prevention of diabetes in healthy volunteers, including subjects with prediabetes, without adverse effects.

Disparate effects of MMP and TIMP modulation on coronary atherosclerosis and associated myocardial fibrosis

Matrix metalloproteinase (MMP) activity is tightly regulated by the endogenous tissue inhibitors (TIMPs), and dysregulated activity contributes to extracellular matrix remodelling. Accordingly, MMP/TIMP balance is associated with atherosclerotic plaque progression and instability, alongside adverse post-infarction cardiac fibrosis and subsequent heart failure. Here, we demonstrate that prolonged high-fat feeding of apolipoprotein (Apo)e-deficient mice triggered the development of unstable coronary artery atherosclerosis alongside evidence of myocardial infarction and progressive sudden death. Accordingly, the contribution of select MMPs and TIMPs to the progression of both interrelated pathologies was examined in Apoe-deficient mice with concomitant deletion of Mmp7, Mmp9, Mmp12, or Timp1 and relevant wild-type controls after 36-weeks high-fat feeding. Mmp7 deficiency increased incidence of sudden death, while Mmp12 deficiency promoted survival, whereas Mmp9 or Timp1 deficiency had no effect. While all mice harboured coronary disease, atherosclerotic burden was reduced in Mmp7-deficient and Mmp12-deficient mice and increased in Timp1-deficient animals, compared to relevant controls. Significant differences in cardiac fibrosis were only observed in Mmp-7-deficient mice and Timp1-deficient animals, which was associated with reduced capillary number. Adopting therapeutic strategies in Apoe-deficient mice, TIMP-2 adenoviral-overexpression or administration (delayed or throughout) of a non-selective MMP inhibitor (RS-130830) had no effect on coronary atherosclerotic burden or cardiac fibrosis. Taken together, our findings emphasise the divergent roles of MMPs on coronary plaque progression and associated post-MI cardiac fibrosis, highlighting the need for selective therapeutic approaches to target unstable atherosclerosis alongside adverse cardiac remodelling while negating detrimental adverse effects on either pathology, with targeting of MMP-12 seeming a suitable target.

Pro-Inflammatory Serum Amyloid a Stimulates Renal Dysfunction and Enhances Atherosclerosis in Apo E-Deficient Mice

Acute serum amyloid A (SAA) is an apolipoprotein that mediates pro-inflammatory and pro-atherogenic pathways. SAA-mediated signalling is diverse and includes canonical and acute immunoregulatory pathways in a range of cell types and organs. This study aimed to further elucidate the roles for SAA in the pathogenesis of vascular and renal dysfunction. Two groups of male ApoE-deficient mice were administered SAA (100 µL, 120 µg/mL) or vehicle control (100 µL PBS) and monitored for 4 or 16 weeks after SAA treatment; tissue was harvested for biochemical and histological analyses at each time point. Under these conditions, SAA administration induced crosstalk between NF-κB and Nrf2 transcriptional factors, leading to downstream induction of pro-inflammatory mediators and antioxidant response elements 4 weeks after SAA administration, respectively. SAA treatment stimulated an upregulation of renal IFN-γ with a concomitant increase in renal levels of p38 MAPK and matrix metalloproteinase (MMP) activities, which is linked to tissue fibrosis. In the kidney of SAA-treated mice, the immunolocalisation of inducible nitric oxide synthase (iNOS) was markedly increased, and this was localised to the parietal epithelial cells lining Bowman’s space within glomeruli, which led to progressive renal fibrosis. Assessment of aortic root lesion at the study endpoint revealed accelerated atherosclerosis formation; animals treated with SAA also showed evidence of a thinned fibrous cap as judged by diffuse collagen staining. Together, this suggests that SAA elicits early renal dysfunction through promoting the IFN-γ-iNOS-p38 MAPK axis that manifests as the fibrosis of renal tissue and enhanced cardiovascular disease.

The relationship between apolipoprotein E gene polymorphism and essential hypertension and the analysis of the efficacy of nanotechnology

The study aimed to detect the genetic polymorphism of apolipoprotein E (Apo E) in residents of Guizhou, China, explore its relationship with essential hypertension, and discuss the efficacy of nanotechnology in the treatment of hypertension. A total of 200 people in Guizhou, China were detected with Apo E polymorphisms and were divided into groups, The experimental group consists of people with essential hypertension and the control group of normal people. The SPSS 26.0 software was used to determine the correlation between Apo E gene polymorphisms and the essential hypertension risk. Logistic regression analysis was adopted to determine the risk factors of the Apo E gene for essential hypertension. Magnetic nanoparticles are used to help extract DNA, improve efficiency, and analyze the distribution of alleles in the population. The distribution frequencies of the six genotypes of E2/2, E2/3, E3/3, E3/4, E2/4, and E4/4 were 1.0%, 15.5%, 64.0%, 17.0%, 1.5%, and 1.0%, respectively, and the distribution frequencies of the three alleles of ε2, ε3, and ε4 were 9.5%, 80.3%, and 10.3%, respectively. There are more Apo E gene ε4 carriers in the experimental group than the control group, and the difference was statistically significant (P <0.05). The Apo E ε4 allele carriers had higher low-density lipoprotein and Apo B levels than the Apo E ε3 and Apo E ε2 gene carriers. Family history of hypertension and Apo E ε4 were both the main risk factors for essential hypertension. This study investigated the relationship between apolipoprotein E gene polymorphism and essential hypertension, and extracted DNA by magnetic nanoparticles to help analyze the distribution of alleles in hypertension population, which could provide theoretical basis for the diagnosis and treatment of essential hypertension in Guizhou Province, China.

Heart function assessment during aging in apolipoprotein E knock-out mice

BACKGROUND: Apolipoprotein (apo) E isoforms have strong correlations with metabolic and cardiovascular diseases. However, it is not clear if apoE has a role in development of non-ischemic cardiomyopathy. Our study aims to analyze the involvement of apoE in non-ischemic cardiomyopathy. METHODS AND RESULTS: Serial echo-cardiographic measurements were performed in old wildtype and apoE deficient (apoE-/-) mice. Morphological and functional cardiac parameters were in normal range in both groups at the age of 12 month. At the age of 18 months, both groups had shown ventricular dilation and increased heart rates. However, the apoE-/- mice presented signs of diastolic dysfunction by hypertrophic changes in left ventricle, due probably to arterial hypertension. The right ventricle was not affected by age or genotype. CONCLUSION: Even in the absence of high fat diet, apoE deficiency in mice induces mild changes in the cardiac function of the left ventricle during aging, by developing diastolic dysfunction, which leads to heart failure with preserved ejection fraction. However, further studies are necessary to conclude over the role of apoE in cardiac physiology and its involvement in development of heart failure.

Absence of Apolipoprotein E is associated with exacerbation of prion pathology and promotes microglial neurodegenerative phenotype

Prion diseases or prionoses are a group of rapidly progressing and invariably fatal neurodegenerative diseases. The pathogenesis of prionoses is associated with self-replication and connectomal spread of PrPSc, a disease specific conformer of the prion protein. Microglia undergo activation early in the course of prion pathogenesis and exert opposing roles in PrPSc mediated neurodegeneration. While clearance of PrPSc and apoptotic neurons have disease-limiting effect, microglia-driven neuroinflammation bears deleterious consequences to neuronal networks. Apolipoprotein (apo) E is a lipid transporting protein with pleiotropic functions, which include controlling of the phagocytic and inflammatory characteristics of activated microglia in neurodegenerative diseases. Despite the significance of microglia in prion pathogenesis, the role of apoE in prionoses has not been established. We showed here that infection of wild type mice with 22L mouse adapted scrapie strain is associated with significant increase in the total brain apoE protein and mRNA levels and also with a conspicuous cell-type shift in the apoE expression. There is reduced expression of apoE in activated astrocytes and marked upregulation of apoE expression by activated microglia. We also showed apoE ablation exaggerates PrPSc mediated neurodegeneration. Apoe−/− mice have shorter disease incubation period, increased load of spongiform lesion, pronounced neuronal loss, and exaggerated astro and microgliosis. Astrocytes of Apoe−/− mice display salient upregulation of transcriptomic markers defining A1 neurotoxic astrocytes while microglia show upregulation of transcriptomic markers characteristic for microglial neurodegenerative phenotype. There is impaired clearance of PrPSc and dying neurons by microglia in Apoe−/− mice along with increased level of proinflammatory cytokines. Our work indicates that apoE absence renders clearance of PrPSc and dying neurons by microglia inefficient, while the excess of neuronal debris promotes microglial neurodegenerative phenotype aggravating the vicious cycle of neuronal death and neuroinflammation.

Apo D and Apo E Levels in Autism Spectrum Disorders

Apo D is an atypical plasma apolipoprotein and a member of the lipocalin protein superfamily. In recent years, Apo D has been identified as an important factor in the pathology of neurodegenerative and neuropsychiatric diseases. Apo D is highly produced in the brain and acts as a multiligand and multifunctional carrier. Apo D binds to and stabilizes Arachidonic acid in the cell membrane and cytosol. Thus, it suppresses inflammation and protects the cell membrane against oxidation. Apo E is important in cholesterol transfer and it has been reported that it may play a role in immune regulation, nerve regeneration, synaptogenesis and neuronal homeostasis. In this study, plasma Apo D and Apo E levels were examined and its possible role in Autism Spectrum Disorders (ASD) pathology was investigated. Thirty-nine subjects with ASD were compared with 30 healthy subjects who typically developed. Accordingly, plasma Apo D and Apo E levels were statistically significantly lower in the ASD group compared to the healthy control group. According to the results of this study, it can be suggested that low levels of Apo D and Apo E may play a role in ASD pathogenesis.