Phellinus rimosus improves mitochondrial energy status and attenuates nephrotoxicity in diabetic rats

Involvement of Tricarboxylic Acid Cycle Metabolites in Kidney Diseases

Mitochondria are complex organelles that orchestrate several functions in the cell. The primary function recognized is energy production; however, other functions involve the communication with the rest of the cell through reactive oxygen species (ROS), calcium influx, mitochondrial DNA (mtDNA), adenosine triphosphate (ATP) levels, cytochrome c release, and also through tricarboxylic acid (TCA) metabolites. Kidney function highly depends on mitochondria; hence mitochondrial dysfunction is associated with kidney diseases. In addition to oxidative phosphorylation impairment, other mitochondrial abnormalities have been described in kidney diseases, such as induction of mitophagy, intrinsic pathway of apoptosis, and releasing molecules to communicate to the rest of the cell. The TCA cycle is a metabolic pathway whose primary function is to generate electrons to feed the electron transport system (ETS) to drives energy production. However, TCA cycle metabolites can also release from mitochondria or produced in the cytosol to exert different functions and modify cell behavior. Here we review the involvement of some of the functions of TCA metabolites in kidney diseases.

The Effects of Folic Acid Administration on Cardiac Oxidative Stress and Cardiovascular Biomarkers in Diabetic Rats

The aim of this study was to examine the effects of folic acid administration on the antioxidant enzyme (superoxide dismutase (SOD) and catalase (CAT)) activities, lactate and malate dehydrogenase (LDH and MDH) activities, and certain LDH and MDH isoform distribution in the cardiac tissue of diabetic Wistar male rats. Diabetes mellitus (DM) was induced by streptozotocin (STZ). There were five groups: C1-control (physiological saline 1 ml/kg, i.p. one day), C2-control with daily physiological saline treatment (1 ml/kg, i.p. 28 days), DM-diabetes mellitus (STZ 100 mg/kg in physiological saline, i.p. one day), FA-folic acid (5 mg/kg in physiological saline, i.p. 28 days), and DM+FA-diabetes mellitus and folic acid group (STZ 100 mg/kg in physiological saline, i.p. one day, and folic acid 5 mg/kg in physiological saline, i.p. 28 days). After four weeks, animal hearts were isolated for measurement of enzyme activities, as well as for histomorphometry analyses. An elevated glucose level and a decreased insulin level were obtained in the DM group. SOD, CAT, and MDH activities were elevated in the DM group, while there was no difference in LDH activity among the groups. In all tested groups, four LDH and three MDH isoforms were detected in the heart tissue, but with differences in their relative activities among the groups. Left ventricular cardiomyocyte transversal diameters were significantly smaller in both diabetic groups. Folic acid treatment of diabetic rats induced a reduced glucose level and reduced CAT, SOD, and MDH activities and alleviated the decrease in cardiomyocyte diameters. In conclusion, increased activities of antioxidant enzymes and MDH may be the consequence of oxidative stress caused by DM. Administration of the folic acid has a protective effect since it leads to reduction in glycemia and activities of the certain examined enzymes in the rats with experimentally induced DM.