Astaxanthin Inhibits H2O2-Induced Excessive Mitophagy and Apoptosis in SH-SY5Y Cells by Regulation of Akt/mTOR Activation.

Oxidative stress, which damages cellular components and causes mitochondrial dysfunction, occurs in a variety of human diseases, including neurological disorders. The clearance of damaged mitochondria via mitophagy maintains the normal function of mitochondria and facilitates cell survival. Astaxanthin is an antioxidant known to have neuroprotective effects, but the underlying mechanisms remain unclear. This study demonstrated that astaxanthin inhibited H2O2-induced apoptosis in SH-SY5Y cells by ameliorating mitochondrial damage and enhancing cell survival. H2O2 treatment significantly reduced the levels of activated Akt and mTOR and induced mitophagy, while pretreatment with astaxanthin prevented H2O2-induced inhibition of Akt and mTOR and attenuated H2O2-induced mitophagy. Moreover, the inhibition of Akt attenuated the protective effect of astaxanthin against H2O2-induced cytotoxicity. Taken together, astaxanthin might inhibit H2O2-induced apoptosis by protecting mitochondrial function and reducing mitophagy. The results also indicate that the Akt/mTOR signaling pathway was critical for the protection of astaxanthin against H2O2-induced cytotoxicity. The results from the present study suggest that astaxanthin can reduce neuronal oxidative injury and may have the potential to be used for preventing neurotoxicity associated with neurodegenerative diseases.

Baseline urine pH is related to effective urine alkalization by short-term alkaline water supplementation: data from a self-controlled study in healthy Chinese volunteers following a systematic review and meta-analysis of literature.

Background: The outcomes of urine alkalization with alkaline water supplementation vary greatly across studies and therefore remain inconclusive, probably arising from differences in study design, ethnic group, and source of alkaline water, which needs further clarification. With a systematic review of literature, followed by an empirical observation among healthy Chinese volunteers, we aimed to investigate the outcomes of urine alkalization with alkaline water vs. daily drinking water, and whether these outcomes are intersected by certain factors such as gender and body mass index (BMI). Methods: We conducted a literature search of related studies on alkaline water supplementation and urine pH using the PubMed, Embase, Medline and Cochrane Library databases. The publication bias was assessed with inverted funnel plotting. Chi-square-based Q-test and I2-statistic test were used to examine the data heterogeneity. The studies were evaluated for quality using the Cochrane risk of bias tool or Newcastle-Ottawa Scale (NOS). The meta-analysis was followed by a study in healthy volunteers. As per protocol, all subjects remained on regular drinking water for one week and were switched to alkaline water for the next week. Urine pH was measured thrice daily and averaged. The mean urine pH values in the first and second weeks were compared for all subjects. Alkalization gains in urine pH (AGU-pH) was computed to determine the outcome of alkaline water supplementation in relation to baseline urine pH. Results: Our systematic review of literature yielded limited data about the effect of alkaline water on urine pH. Despite an increase in urine pH after supplementation of alkaline water as indicated by the random-effect model, a high heterogeneity across the included studies (I2=94%, P<0.001) precluded a robust determination. In our volunteer study, alkaline water led to elevation of urine pH from baseline in 84.9% of all subjects or by BMI stratification. Effective urine alkalization was noted in males but not in females. Subjects who presented effective urine alkalization had significantly lower baseline urine pH compared with those who did not (5.94±0.27 vs. 6.22±0.22, P=0.0016). The negative correlation between AGU-pH and baseline urine pH (r=-0.236, P=0.044) and receiver operating curve (ROC) analysis suggested that subjects with more "acidic" urine, particularly those with a baseline urine pH ≤6.0 (maximum Youden index =1.548, cut-off =5.977), could show more pronounced outcome of urine alkalization from oral alkaline water. Conclusions: Our meta-analysis and human subjects study revealed that alkaline water supplementation may be useful for urine alkalization, particularly in individuals with a lower urine pH. The outcomes seem not significantly pronounced in females, although more efforts warranted for validation. Short-term use of alkaline water is well-tolerated and not associated with over-alkalization of the urine.

[Measurement of Phase-controlled Characteristics of HIFU Based on Infrared Thermal Imaging].

Phase-Controlled high intensity focused ultrasound 3D temperature distribution is the key indicator for measuring the efficiency of HIFU transducer. Considerable progress has been achieved in the use of infrared (IR) imaging techniques for qualitative mapping of acoustic and thermal field of high intensity focused ultrasound (HIFU) transducers. This article proposes a method to measure phased-controlled characteristics of HIFU based on infrared thermal imaging and establishes a whole measurement system to make the method more quantitative and reliable. The result shows that the proposed measurement system is able to measure pHIFU characteristics rapidly and precisely, which will be of great significance in standardizing the measurement of pHIFU acoustic field.