Characterization of an i.p. D-galactose-induced cataract model in rats

The Consumption of Beeswax Alcohol (BWA, Raydel®) Improved Zebrafish Motion and Swimming Endurance by Protecting the Brain and Liver from Oxidative Stress Induced by 24 Weeks of Supplementation with High-Cholesterol and D-Galactose Diets: A Comparative Analysis Between BWA and Coenzyme Q10

The prolonged consumption of D-galactose (Gal) has been associated with severe damage in the liver and brain via exacerbation of oxidative stress, non-enzymatic glycation, and the aging process. The current study was initiated for a comparative assessment of beeswax alcohol (BWA, final 0.5% and 1.0% w/w) and coenzyme Q10 (CoQ10, final 0.5% and 1.0% w/w) against high-cholesterol (HC, final 4%, w/w) and -galactose (Gal, final 30%, w/w)-induced adverse events in zebrafish during 24 weeks of consumption. The survivability of zebrafish decreased to 82.1% due to HC+Gal exposure, but this was substantially improved (91.0%) with the consumption of 0.5% and 1.0% BWA. In contrast, no protective effect of CoQ10 consumption (1.0%) was observed on the survivability of zebrafish. Nevertheless, both BWA and CoQ10 displayed a significant (p < 0.001) preventive effect against HC+Gal-induced body weight enhancement. The HC+Gal-induced cognitive changes, marked by staggered and confused swimming behavior, and retarded swimming speed and motion patterns (restricted to the bottom of the tank), were efficiently restored by BWA. A significantly higher residence time in the upper half of the tank, 3.1-and 4.5-fold reduced latency time along with 3.5-fold and 4.1-fold higher swimming distance, was logged in the 0.5% and 1.0% BWA groups, respectively, than the zebrafish that consumed HC+Gal. In addition, BWA effectively enhanced plasma ferric ion reduction (FRA) and paraoxonase (PON) activity and alleviated the total cholesterol (TC), triglyceride (TG), and blood glucose levels disrupted by the consumption of HC+Gal. Also, the HC+Gal-alleviated plasma high-density lipoprotein-cholesterol (HDL-C) was 2.6-fold (p < 0.001) enhanced in the group that consumed 1.0% BWA, which was significantly 1.5-fold (p < 0.001) better than the effect of 1.0% CoQ10. Similarly, BWA displayed a superior impact over CoQ10 to mitigate HC+Gal-induced plasma AST and ALT levels, hepatic IL-6 production, generation of oxidized species, cellular senescence, and fatty liver changes. Moreover, BWA protects the brain against HC+Gal-induced oxidative stress, apoptosis, and myelin sheath degeneration. Conclusively, compared to CoQ10, BWA efficiently can the HC+Gal-impaired brain and liver functionality to subside and improves the dyslipidemia and cognitive behavior of zebrafish.

Reduction in Lens Epithelial Cell Senescence Burden through Dasatinib Plus Quercetin or Rapamycin Alleviates D-Galactose-Induced Cataract Progression

Senescent cells accumulate in aged organisms and promote the progression of age-related diseases including cataracts. Therefore, we aimed to study the therapeutic effects of senescence-targeting drugs on cataracts. In this study, a 28-day D-galactose-induced cataract rat model was used. The opacity index, a grading based on slit-lamp observations, was used to assess lens cloudiness. Furthermore, the average lens density (ALD), lens density standard deviation (LDSD), and maximum lens density (MLD) obtained from Scheimpflug images were used to assess lens transparency. Immunohistochemical stainings for p16 and γH2AX were used as hallmarks of senescence. We treated rat cataract models with the senolytic drug combination dasatinib plus quercetin (D+Q) and senescence-associated secretory phenotype (SASP) inhibitors. In comparison to control lenses, D-galactose-induced cataract lenses showed a higher opacity index, ALD, LDSD, and MLD values, as well as accumulation of senescent lens epithelial cells (LECs). After D+Q treatment, ALD, LDSD, and MLD values on day 21 were significantly lower than those of vehicle-treated model rats. The expression levels of p16 and γH2AX were also reduced after D+Q administration. In addition, the SASP inhibitor rapamycin decreased the opacity index, ALD, LDSD, and MLD values on day 21. In conclusion, D+Q alleviated D-galactose-induced cataract progression by reducing the senescent LEC burden in the early stage of cataract.

d-Galactose treatment increases ACE2, TMPRSS2, and FURIN and reduces SERPINA1 mRNA expression in A549 human lung epithelial cells

Several comorbidities including diabetes, immune deficiency, and chronic respiratory disorders increase the risk of severe Covid-19 and fatalities among SARS-CoV-2 infected individuals. Severe Covid-19 risk among diabetes patients may reflect reduced immune response to viral infections. SARS-CoV-2 initially infects respiratory tract epithelial cells by binding to the host cell membrane ACE2, followed by proteolytic priming for cell entry by the host cell membrane serine protease TMPRSS2. Additionally, the protease FURIN facilitates cell exit of mature SARS-CoV-2 virions. Alpha-1 antitrypsin (AAT), the major plasma serine protease inhibitor, encoded by SERPINA1, is known to promote immune response to viral infections. AAT inhibits neutrophil elastase, a key inflammatory serine protease implicated in alveolar cell damage during respiratory infections, and AAT deficiency is associated with susceptibility to lung infections. AAT is implicated in Covid-19 as it inhibits TMPRSS2, a protease essential for SARS-CoV-2 cell entry. Here we show that treatment of A549 human lung epithelial cells for 7 days with 25 mM d-galactose, an inducer of diabetic-like and oxidative stress cellular phenotypes, leads to increased mRNA levels of ACE2, TMPRSS2, and FURIN, along with reduced SERPINA1 mRNA. Together, the dysregulated transcription of these genes following d-galactose treatment suggests that chronic diabetic-like conditions may facilitate SARS-CoV-2 infection of lung epithelial cells. Our findings may in part explain the higher severe Covid-19 risk in diabetes, and highlight the need to develop special treatment protocols for diabetic patients.