Objective To examine the expression of angiotensin Ⅱ (Ang Ⅱ) receptor subtypes in human left and right atrial tissue in atrial fibrillation underlying rheumatic heart disease. Methods Atrial tissue samples were obtained from 39 patients with rheumatic heart disease, 25 with atrial fibrillation(AF) and 14 with sinus rhythm(SR) during open heart surgery. AT1 and AT2 mRNA levels were measured with semi-quantitative reverse transcription polymerase chain reaction techniques. AT1 and AT2 protein levels were measured with immunohistochemical techniques. Results Compared with that of the SR group, left atrial inner diameter was significantly increased in the patients of the AF group. The AT1 mRNA and protein levels in the LA significantly increased in patients with AF compared with those in patients with SR (P < 0. 05), whereas AT2 mRNA and protein were not significantly altered. Investigations of Ang Ⅱ receptor subtypes' mRNA and protein levels in the RA did not exhibit any significant changes either in AT1 or AT2 in patients with AF and SR. Conclusions AF is associated with an up-regulation of AT1 in LA, but does not appear to influence the AT2 expression. This may indicate a possible pathophysiologie role for renin-angiotensin system in the development of AF. The series of effects mediated by ATI activation may be one of the molecular mechanisms involved in the process of atrial remodeling.

Ganoderic triterpenoids (GTs) are the primary bioactive constituents of the Basidiomycotina fungus,

Ganoderma lucidum is a mushroom widely used for its edible and medicinal properties. Primary bioactive constituents of G. lucidum are ganoderic triterpenoids (GTs), which exhibit important pharmacological activity. Abscisic acid (ABA), a plant hormone, is associated with plant growth, development, and stress responses. ABA can also affect the growth, metabolism, and physiological activities of different fungi and participates in the regulation of the tetracyclic triterpenes of some plants. Our findings indicated that ABA treatment promoted GT accumulation by regulating the gene expression levels (squalene synthase (sqs), 3-hydroxy-3-methylglutaryl-CoA reductase (hmgr), and lanosterol synthase (ls)), and also activated cytosolic Ca²⁺ channels. Furthermore, under ABA mediation, exogenous Ca²⁺ donors and inhibitors directly affected the cytosolic Ca²⁺ concentration and related gene expression in Ca²⁺ signaling. Our study also revealed that ABA-mediated cytosolic Ca²⁺ played a crucial regulatory role in GT biosynthesis, accompanied by antioxidant defense modulation with increasing superoxide dismutase (SOD) activity and ascorbate peroxidase (APX) activity, and the resistance ability of O₂^•- and glutathione (GSH) contents.
Reishi/metabolism* ; Triterpenes/metabolism* ; Abscisic Acid/metabolism* ; Antioxidants/metabolism*