Browsing by Author "Antone, Unigunde"

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    Acute and long-term administration of palmitoylcarnitine induces muscle-specific insulin resistance in mice
    (2017-09-01) Liepinsh, Edgars; Makrecka-Kuka, Marina; Makarova, Elina; Volska, Kristine; Vilks, Karlis; Sevostjanovs, Eduards; Antone, Unigunde; Kuka, Janis; Vilskersts, Reinis; Lola, Daina; Loza, Einars; Grinberga, Solveiga; Dambrova, Maija; Faculty of Pharmacy
    Acylcarnitine accumulation has been linked to perturbations in energy metabolism pathways. In this study, we demonstrate that long-chain (LC) acylcarnitines are active metabolites involved in the regulation of glucose metabolism in vivo. Single-dose administration of palmitoylcarnitine (PC) in fed mice induced marked insulin insensitivity, decreased glucose uptake in muscles, and elevated blood glucose levels. Increase in the content of LC acylcarnitine induced insulin resistance by impairing Akt phosphorylation at Ser473. The long-term administration of PC using slow-release osmotic minipumps induced marked hyperinsulinemia, insulin resistance, and glucose intolerance, suggesting that the permanent accumulation of LC acylcarnitines can accelerate the progression of insulin resistance. The decrease of acylcarnitine content significantly improved glucose tolerance in a mouse model of diet-induced glucose intolerance. In conclusion, we show that the physiological increase in content of acylcarnitines ensures the transition from a fed to fasted state in order to limit glucose metabolism in the fasted state. In the fed state, the inability of insulin to inhibit LC acylcarnitine production induces disturbances in glucose uptake and metabolism. The reduction of acylcarnitine content could be an effective strategy to improve insulin sensitivity.
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    Plasma acylcarnitine concentrations reflect the acylcarnitine profile in cardiac tissues
    (2017-12-01) Makrecka-Kuka, Marina; Sevostjanovs, Eduards; Vilks, Karlis; Volska, Kristine; Antone, Unigunde; Kuka, Janis; Makarova, Elina; Pugovics, Osvalds; Dambrova, Maija; Liepinsh, Edgars; Faculty of Pharmacy
    Increased plasma concentrations of acylcarnitines (ACs) are suggested as a marker of metabolism disorders. The aim of the present study was to clarify which tissues are responsible for changes in the AC pool in plasma. The concentrations of medium- and long-chain ACs were changing during the fed-fast cycle in rat heart, muscles and liver. After 60 min running exercise, AC content was increased in fasted mice muscles, but not in plasma or heart. After glucose bolus administration in fasted rats, the AC concentrations in plasma decreased after 30 min but then began to increase, while in the muscles and liver, the contents of medium- and long-chain ACs were unchanged or even increased. Only the heart showed a decrease in medium- and long-chain AC contents that was similar to that observed in plasma. In isolated rat heart, but not isolated-contracting mice muscles, the significant efflux of medium- and long-chain ACs was observed. The efflux was reduced by 40% after the addition of glucose and insulin to the perfusion solution. Overall, these results indicate that during fed-fast cycle shifting the heart determines the medium- and long-chain AC profile in plasma, due to a rapid response to the availability of circulating energy substrates.
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    Propionic Acid Fermentation—Study of Substrates, Strains, and Antimicrobial Properties
    (2023-01) Antone, Unigunde; Ciprovica, Inga; Zolovs, Maksims; Scerbaka, Rita; Liepins, Janis; Statistics Unit
    Since milk whey is an abundant dairy by-product and a significant threat to the environment, its utilization is of great interest. The study compares valorization of lactose and lactates—the main carbon sources of whey—by fermentation—an environmentally friendly process. Antimicrobials released during fermentation by food-grade bacteria can help increase the microbiological safety of food. Propionic acid—a strong antimicrobial—is obtained mainly by the petrochemical route, yet there is increasing interest in its synthesis in biotechnological pathway. Five strains of propionic acid bacteria (Acidipropionibacterium acidipropionici, Propionibacterium cyclohexanicum, Propionibacterium freudenreichii, Acidipropionibacterium jensenii and Acidipropionibacterium thoenii) were investigated for their ability to produce organic acids and biomass using Na lactate or lactose as carbon sources. Selected fermentates were investigated for their antimicrobial efficacy during in vitro studies with foodborne pathogens: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus. Results confirm that the production of acids and biomass is considerably influenced by the added carbon source. The tested fermentates have strong and specific antimicrobial activity against Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus. In addition, inhibition of Staphylococcus aureus and Klebsiella pneumonia depends on the activity of produced bacteriocins. The article also discusses the possibility of increasing the antimicrobial activity of fermentates by acidification