Metabolomics analysis reveals changes related to pseudocyst formation induced by iron depletion in Trichomonas vaginalis

BACKGROUND

Iron is an essential element for cellular functions, such as energy metabolism. Trichomonas vaginalis, a human urogenital tract pathogen, is capable of surviving in the environment without sufficient iron supplementation. Pseudocysts (cyst-like structures) are an environmentally tolerated stage of this parasite while encountering undesired conditions, including iron deficiency. We previously demonstrated that iron deficiency induces more active glycolysis but a drastic downregulation of hydrogenosomal energy metabolic enzymes. Therefore, the metabolic direction of the end product of glycolysis is still controversial.

METHODS

In the present work, we conducted an LC‒MS-based metabolomics analysis to obtain accurate insights into the enzymatic events of T. vaginalis under iron-depleted (ID) conditions.

RESULTS

First, we showed the possible digestion of glycogen, cellulose polymerization, and accumulation of raffinose family oligosaccharides (RFOs). Second, a medium-chain fatty acid (MCFA), capric acid, was elevated, whereas most detected C18 fatty acids were reduced significantly. Third, amino acids were mostly reduced, especially alanine, glutamate, and serine. Thirty-three dipeptides showed significant accumulation in ID cells, which was probably associated with the decrease in amino acids. Our results indicated that glycogen was metabolized as the carbon source, and the structural component cellulose was synthesized at same time. The decrease in C18 fatty acids implied possible incorporation in the membranous compartment for pseudocyst formation. The decrease in amino acids accompanied by an increase in dipeptides implied incomplete proteolysis. These enzymatic reactions (alanine dehydrogenase, glutamate dehydrogenase, and threonine dehydratase) were likely involved in ammonia release.

CONCLUSION

These findings highlighted the possible glycogen utilization, cellulose biosynthesis, and fatty acid incorporation in pseudocyst formation as well as NO precursor ammonia production induced by iron-depleted stress.

The association between walking speed and risk of cardiovascular disease in middle-aged and elderly people in Taiwan, a community-based, cross-sectional study

BACKGROUND AND AIMS

The aim of this study was to investigate the association between walking speed and cardiovascular disease (CVD) risk among community-dwelling middle-aged and elderly populations in Taiwan.

METHODS

This was a cross-sectional and community-based study with 400 participants aged 50 years and over recruited from a community health promotion project in 2014 in Guishan district, Taoyuan city. We excluded 91 people, and a total of 309 participants were eligible for analysis. The statistical methods used in this study were one-way ANOVA and the Chi-square test, Pearson's correlation test and logistic regression model.

RESULTS

In total, 309 participants (98 males and 211 females) aged 50 to 74 (62.05 ± 6.21) years without a CVD history were enrolled in this study. The walking speed gradually decreased from the low CVD risk group to the high CVD risk group (p < 0.05). A significant inverse association between walking speed and CVD risk was confirmed with a Pearson's correlation coefficient of-0.143 (p < 0.05) in middle-aged people, but this significant inverse association was not shown in elderly people. The multivariate logistic regression model for predicting CVD risk and walking speed with an adjusted odds ratio (OR) was 0.127 (95% CI = 0.021-0.771) in middle-aged people with adjustment for sex, age, waist circumference (WC), hypertension (HTN), diabetes mellitus (DM), and hyperlipidemia (p < 0.05).

CONCLUSION

Our study clearly shows that slow walking speed is associated with an increased risk of CVD in middle-aged people rather than in elderly people.