RESUMEN
Here, we describe the identification of an antibiotic class acting via LpxH, a clinically unexploited target in lipopolysaccharide synthesis. The lipopolysaccharide synthesis pathway is essential in most Gram-negative bacteria and there is no analogous pathway in humans. Based on a series of phenotypic screens, we identified a hit targeting this pathway that had activity on efflux-defective strains of Escherichia coli. We recognized common structural elements between this hit and a previously published inhibitor, also with activity against efflux-deficient bacteria. With the help of X-ray structures, this information was used to design inhibitors with activity on efflux-proficient, wild-type strains. Optimization of properties such as solubility, metabolic stability and serum protein binding resulted in compounds having potent in vivo efficacy against bloodstream infections caused by the critical Gram-negative pathogens E. coli and Klebsiella pneumoniae. Other favorable properties of the series include a lack of pre-existing resistance in clinical isolates, and no loss of activity against strains expressing extended-spectrum-ß-lactamase, metallo-ß-lactamase, or carbapenemase-resistance genes. Further development of this class of antibiotics could make an important contribution to the ongoing struggle against antibiotic resistance.
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Antibacterianos , Lipopolisacáridos , Humanos , Antibacterianos/química , Escherichia coli/metabolismo , Bacterias Gramnegativas/metabolismo , beta-Lactamasas/genética , Pruebas de Sensibilidad MicrobianaRESUMEN
Right ventricular (RV) and left ventricular (LV) dysfunction is common in a significant number of hospitalized coronavirus disease 2019 (COVID-19) patients. This study was conducted to assess whether the improved mitochondrial bioenergetics by cardiometabolic drug meldonium can attenuate the development of ventricular dysfunction in experimental RV and LV dysfunction models, which resemble ventricular dysfunction in COVID-19 patients. Effects of meldonium were assessed in rats with pulmonary hypertension-induced RV failure and in mice with inflammation-induced LV dysfunction. Rats with RV failure showed decreased RV fractional area change (RVFAC) and hypertrophy. Treatment with meldonium attenuated the development of RV hypertrophy and increased RVFAC by 50%. Mice with inflammation-induced LV dysfunction had decreased LV ejection fraction (LVEF) by 30%. Treatment with meldonium prevented the decrease in LVEF. A decrease in the mitochondrial fatty acid oxidation with a concomitant increase in pyruvate metabolism was noted in the cardiac fibers of the rats and mice with RV and LV failure, respectively. Meldonium treatment in both models restored mitochondrial bioenergetics. The results show that meldonium treatment prevents the development of RV and LV systolic dysfunction by enhancing mitochondrial function in experimental models of ventricular dysfunction that resembles cardiovascular complications in COVID-19 patients.
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Cardiotónicos/farmacología , Metilhidrazinas/farmacología , Animales , COVID-19/complicaciones , Cardiotónicos/uso terapéutico , Cardiotoxicidad/tratamiento farmacológico , Modelos Animales de Enfermedad , Endotelio/efectos de los fármacos , Insuficiencia Cardíaca/tratamiento farmacológico , Insuficiencia Cardíaca/metabolismo , Ventrículos Cardíacos/efectos de los fármacos , Peróxido de Hidrógeno/metabolismo , Pulmón/efectos de los fármacos , Masculino , Metilhidrazinas/uso terapéutico , Ratones Endogámicos C57BL , Mitocondrias/efectos de los fármacos , Saturación de Oxígeno/efectos de los fármacos , Ratas Sprague-Dawley , Especies Reactivas de Oxígeno/metabolismo , Daño por Reperfusión/tratamiento farmacológico , Volumen Sistólico/efectos de los fármacos , Disfunción Ventricular Izquierda/tratamiento farmacológico , Disfunción Ventricular Derecha/tratamiento farmacológico , Tratamiento Farmacológico de COVID-19RESUMEN
PURPOSE: Sodium-glucose cotransporter 2 (SGLT2) inhibitors prevent heart failure and decrease cardiovascular mortality in patients with type 2 diabetes. Heart failure is associated with detrimental changes in energy metabolism, and the preservation of cardiac mitochondrial function is crucial for the failing heart. However, to date, there are no data to support the hypothesis that treatment with a SGLT2 inhibitor might alter mitochondrial bioenergetics in diabetic failing hearts. Thus, the aim of this study was to investigate the protective effects of empagliflozin on mitochondrial fatty acid metabolism. METHODS: Mitochondrial dysfunction was induced by 18 weeks of high-fat diet (HFD)-induced lipid overload. Empagliflozin was administered at a dose of 10 mg/kg in a chow for 18 weeks. Palmitate metabolism in vivo, cardiac mitochondrial functionality and biochemical parameters were measured. RESULTS: In HFD-fed mice, palmitate uptake was 1.7, 2.3, and 1.9 times lower in the heart, liver, and kidneys, respectively, compared with that of the normal chow control group. Treatment with empagliflozin increased palmitate uptake and decreased the accumulation of metabolites of incomplete fatty acid oxidation in cardiac tissues, but not other tissues, compared with those of the HFD control group. Moreover, empagliflozin treatment resulted in fully restored fatty acid oxidation pathway-dependent respiration in permeabilized cardiac fibers. Treatment with empagliflozin did not affect the biochemical parameters related to hyperglycemia or hyperlipidemia. CONCLUSION: Empagliflozin treatment preserves mitochondrial fatty acid oxidation in the heart under conditions of chronic lipid overload.
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Compuestos de Bencidrilo/farmacología , Dieta Alta en Grasa , Dislipidemias/tratamiento farmacológico , Metabolismo Energético/efectos de los fármacos , Glucósidos/farmacología , Mitocondrias Cardíacas/efectos de los fármacos , Palmitatos/metabolismo , Inhibidores del Cotransportador de Sodio-Glucosa 2/farmacología , Animales , Modelos Animales de Enfermedad , Dislipidemias/etiología , Dislipidemias/metabolismo , Masculino , Ratones Endogámicos C57BL , Mitocondrias Cardíacas/metabolismo , Oxidación-ReducciónRESUMEN
BACKGROUND: The health-promoting properties of apples are directly related to the biologically active compounds that they contain, such as polyphenols. The objective of this study was to prepare a low-sugar, fibre- and phlorizin-enriched powder from unripe apples and to gain insight regarding its anti-hyperglycaemic activity in healthy volunteers. RESULTS: The unripe apples (Malus domestica Borkh.) were collected 30 days after the full bloom day; blanched and pressed to obtain apple pomace which was then processed with a food cutter, oven-dried and milled to prepare apple powder. The concentrations of total sugars, water-soluble pectin and phlorizin in the apple preparation were 153.44 ± 2.46, 27.73 ± 0.51 and 12.61 ± 0.15 g kg(-1), respectively. Acute ingestion of the apple preparation improved glucose metabolism in the oral glucose tolerance test (OGTT) in six healthy volunteers by reducing the postprandial glucose response at 15 to 30 min by approximately two-fold (P < 0.05) and by increasing urinary glucose excretion during the 2- to 4-h interval of the OGTT by five-fold (P < 0.05). CONCLUSION: The results obtained indicate that the dried and powdered pomace of unripe apples can be used as a health-promoting natural product for the reduction of postprandial glycaemia and to improve the health of patients with diabetes.
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Glucemia/metabolismo , Sacarosa en la Dieta/metabolismo , Frutas/química , Hipoglucemiantes/farmacología , Malus/química , Florizina/farmacología , Extractos Vegetales/farmacología , Fibras de la Dieta/análisis , Fibras de la Dieta/farmacología , Sacarosa en la Dieta/análisis , Femenino , Prueba de Tolerancia a la Glucosa , Voluntarios Sanos , Humanos , Hiperglucemia/sangre , Hiperglucemia/tratamiento farmacológico , Hipoglucemiantes/análisis , Pectinas/análisis , Pectinas/farmacología , Florizina/análisis , Extractos Vegetales/química , Polifenoles/farmacología , Periodo Posprandial , Polvos , Valores de ReferenciaRESUMEN
In the heart, a nutritional state (fed or fasted) is characterized by a unique energy metabolism pattern determined by the availability of substrates. Increased availability of acylcarnitines has been associated with decreased glucose utilization; however, the effects of long-chain acylcarnitines on glucose metabolism have not been previously studied. We tested how changes in long-chain acylcarnitine content regulate the metabolism of glucose and long-chain fatty acids in cardiac mitochondria in fed and fasted states. We examined the concentrations of metabolic intermediates in plasma and cardiac tissues under fed and fasted states. The effects of substrate availability and their competition for energy production at the mitochondrial level were studied in isolated rat cardiac mitochondria. The availability of long-chain acylcarnitines in plasma reflected their content in cardiac tissue in the fed and fasted states, and acylcarnitine content in the heart was fivefold higher in fasted state compared to the fed state. In substrate competition experiments, pyruvate and fatty acid metabolites effectively competed for the energy production pathway; however, only the physiological content of acylcarnitine significantly reduced pyruvate and lactate oxidation in mitochondria. The increased availability of long-chain acylcarnitine significantly reduced glucose utilization in isolated rat heart model and in vivo. Our results demonstrate that changes in long-chain acylcarnitine contents could orchestrate the interplay between the metabolism of pyruvate-lactate and long-chain fatty acids, and thus determine the pattern of energy metabolism in cardiac mitochondria.
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Carnitina/análogos & derivados , Metabolismo Energético , Glucosa/metabolismo , Mitocondrias Cardíacas/fisiología , Palmitoilcarnitina/administración & dosificación , Animales , Carnitina/metabolismo , Ayuno , Ácidos Grasos/metabolismo , Masculino , Ratones , Ratones Endogámicos ICR , Modelos Animales , Ratas , Ratas WistarRESUMEN
l-Carnitine is a cofactor in the energy metabolism pathways where it drives the uptake and oxidation of long chain fatty acids (LCFA) by mitochondria. LCFA lipotoxicity causes mitochondrial damage and results in an insufficient energy supply and a decrease in l-carnitine content limits LCFA flux and protects mitochondria. Here, we tested whether the inhibition of GBB dioxygenase (BBOX) or organic cation transporter 2 (OCTN2) is the most effective strategy to decrease l-carnitine content. The activity of 51 compounds was tested and we identified selective inhibitors of OCTN2. In contrast to selective inhibitors of BBOX, OCTN2 inhibitors induced a 10-fold decrease in l-carnitine content in the heart tissues and a significant 35% reduction of myocardial infarct size. In addition, OCTN2 inhibition correlated with the inhibitor content in the heart tissues, and OCTN2 could potentially be an efficient target to increase drug transport into tissues and to reduce drug elimination by urine. In conclusion, the results of this study confirm that selective inhibition of OCTN2, compared to selective inhibition of BBOX, is a far more effective approach to decrease l-carnitine content and to induce cardioprotective effects. OCTN2 could potentially be an efficient tool to increase drug transport in tissues and to reduce drug elimination via urine.
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Cardiotónicos/uso terapéutico , Carnitina/metabolismo , Infarto del Miocardio/tratamiento farmacológico , Proteínas de Transporte de Catión Orgánico/antagonistas & inhibidores , gamma-Butirobetaína Dioxigenasa/antagonistas & inhibidores , Animales , Cardiotónicos/farmacología , Carnitina/sangre , Carnitina/orina , Masculino , Infarto del Miocardio/metabolismo , Miocardio/metabolismo , Ratas Wistar , Miembro 5 de la Familia 22 de Transportadores de SolutosRESUMEN
In a screening programme directed towards the discovery of drugs that could enhance sexual activity, we found that a decoction of the root bark of Neobeguea mahafalensis displayed an extraordinarily high potency and remarkably long duration in augmenting sexual activity in male rodents. Bioassay-guided fractionation led to the isolation of two pharmacoactive constituents, which turned out to be novel 1,8,9-orthoacetate phragmalin limonoids that we named libiguins A and B, each with a C-16/30 δ-lactone ring. Chemical structures were established by the interpretation of their 1D and 2D NMR data. In vivo pharmacological tests showed that starting with a treatment from 0.004-0.4 mg/kg/day for three consecutive days, over a 3-h sampling period, these limonoids induced a long-lasting augmentation of frequency and sustainment of mounting behaviour in male rodents, with an effect lasting for up to 11 days post-treatment. Libiguin A proved to be markedly more potent than libiguin B. This report is the first of limonoids having such an effect, and the findings could lead to novel therapies for the treatment of sexual dysfunction. Moreover, the results can serve as an opening to elucidate the central physiological control of mating behaviour, which is still not well mapped out.
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Afrodisíacos/farmacología , Limoninas/farmacología , Meliaceae/química , Extractos Vegetales/farmacología , Conducta Sexual/efectos de los fármacos , Animales , Afrodisíacos/aislamiento & purificación , Limoninas/química , Limoninas/aislamiento & purificación , Masculino , Ratones , Estructura Molecular , Corteza de la Planta , Extractos Vegetales/química , Raíces de Plantas , RatasRESUMEN
Birch outer bark extract (BBE), containing pentacyclic triterpenes such as betulin, lupeol, and betulinic acid, is a widely recognized natural product renowned for its diverse pharmacological effects. However, its limited water solubility restricts its bioavailability. Therefore, the main objective is to enhance the bioavailability of BBE for pharmaceutical use. In this study, we aimed to develop a dispersion system utilizing a unique oleogel-producing method through the recrystallization of BBE from an ethanol solution in the oil phase. We generated an oleogel that demonstrates a notable 42-80-fold improvement in betulin and lupeol peroral bioavailability from BBE in Wistar rats, respectively. A physical paste-like BBE hydrogel developed with antisolvent precipitation showed a 16-56-fold increase in the bioavailability of betulin and lupeol from BBE in rat blood plasma, respectively. We also observed that the repeated administration of the BBE oleogel did not exhibit any toxicity at the tested dose (38.5 mg/kg betulin, 5.2 mg/kg lupeol, 1.5 mg/kg betulinic acid daily for 7 days). Betulin and betulinic acid were not detected in rat heart, liver, kidney, or brain tissues after the peroral administration of the oleogel daily for 7 days. Lupeol was found in rat heart, liver, and kidney tissues.
RESUMEN
BACKGROUND AND PURPOSE: Statins are competitive inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (HMGCR), and exert adverse effects on mitochondrial function, although the mechanisms underlying these effects remain unclear. We used a tamoxifen-induced Hmgcr-knockout (KO) mouse model, a multi-omics approach and mitochondrial function assessments to investigate whether decreased HMGCR activity impacts key liver energy metabolism pathways. EXPERIMENTAL APPROACH: We established a new mouse strain using the Cre/loxP system, which enabled whole-body deletion of Hmgcr expression. These mice were crossed with Rosa26Cre mice and treated with tamoxifen to delete Hmgcr in all cells. We performed transcriptomic and metabolomic analyses and thus evaluated time-dependent changes in metabolic functions to identify the pathways leading to cell death in Hmgcr-KO mice. KEY RESULTS: Lack of Hmgcr expression resulted in lethality, due to acute liver damage caused by rapid disruption of mitochondrial fatty acid ß-oxidation and very high accumulation of long-chain (LC) acylcarnitines in both male and female mice. Gene expression and KO-related phenotype changes were not observed in other tissues. The progression to liver failure was driven by diminished peroxisome formation, which resulted in impaired mitochondrial and peroxisomal fatty acid metabolism, enhanced glucose utilization and whole-body hypoglycaemia. CONCLUSION AND IMPLICATIONS: Our findings suggest that HMGCR is crucial for maintaining energy metabolism balance, and its activity is necessary for functional mitochondrial ß-oxidation. Moreover, statin-induced adverse reactions might be rescued by the prevention of LC acylcarnitine accumulation.
Asunto(s)
Carnitina , Ácidos Grasos , Hidroximetilglutaril-CoA Reductasas , Hígado , Ratones Noqueados , Oxidación-Reducción , Animales , Femenino , Masculino , Ratones , Carnitina/análogos & derivados , Carnitina/metabolismo , Carnitina/farmacología , Ácidos Grasos/metabolismo , Hidroximetilglutaril-CoA Reductasas/metabolismo , Hidroximetilglutaril-CoA Reductasas/genética , Hígado/metabolismo , Hígado/efectos de los fármacos , Ratones Endogámicos C57BL , Mitocondrias/metabolismo , Mitocondrias/efectos de los fármacos , Oxidación-Reducción/efectos de los fármacosRESUMEN
The aim of the present study was to investigate the effects of vascular tissue levels of l-carnitine and its precursor, γ-butyrobetaine (GBB), on the development of endothelial dysfunction induced by 5 µmol/L lysophosphatidylcholine (LPC), 10 mmol/L triglycerides (TG) or a high glucose concentration (44 mmol/L). Changes in vascular tissue levels of l-carnitine and GBB were induced by administration of l-carnitine (100 mg/kg), mildronate (100 mg/kg; an inhibitor of l-carnitine synthesis) or their combination to male Wistar rats for 2 weeks. Treatment with l-carnitine elevated vascular tissue levels of l-carnitine, whereas administration of mildronate reduced l-carnitine levels and increased GBB levels. Experimental animals that received the combination of both drugs showed elevated tissue levels of GBB. The results from organ bath experiments demonstrated that increased GBB levels with preserved l-carnitine content in vascular tissues attenuated the development of endothelial dysfunction induced by high glucose. However, changes in vascular tissue l-carnitine and GBB levels had no impact on endothelial dysfunction induced by TG or LPC. The results demonstrate that increased levels of GBB with preserved l-carnitine content in vascular tissue attenuate the development of endothelial dysfunction induced by high glucose concentrations.
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Betaína/análogos & derivados , Carnitina/metabolismo , Carnitina/farmacología , Endotelio Vascular/metabolismo , Glucosa/farmacología , Animales , Aorta/efectos de los fármacos , Aorta/metabolismo , Betaína/metabolismo , Fármacos Cardiovasculares/administración & dosificación , Fármacos Cardiovasculares/farmacología , Carnitina/administración & dosificación , Quimioterapia Combinada , Glucosa/administración & dosificación , Masculino , Metilhidrazinas/administración & dosificación , Metilhidrazinas/farmacología , Ratas , Ratas WistarRESUMEN
Long-chain ω-3 polyunsaturated fatty acids (PUFAs) are known to induce cardiometabolic benefits, but the metabolic pathways of their biosynthesis ensuring sufficient bioavailability require further investigation. Here, we show that a pharmacological decrease in overall fatty acid utilization promotes an increase in the levels of PUFAs and attenuates cardiometabolic disturbances in a Zucker rat metabolic syndrome model. Metabolome analysis showed that inhibition of fatty acid utilization by methyl-GBB increased the concentration of PUFAs but not the total fatty acid levels in plasma. Insulin sensitivity was improved, and the plasma insulin concentration was decreased. Overall, pharmacological modulation of fatty acid handling preserved cardiac glucose and pyruvate oxidation, protected mitochondrial functionality by decreasing long-chain acylcarnitine levels, and decreased myocardial infarct size twofold. Our work shows that partial pharmacological inhibition of fatty acid oxidation is a novel approach to selectively increase the levels of PUFAs and modulate lipid handling to prevent cardiometabolic disturbances.
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Ácidos Docosahexaenoicos/metabolismo , Ácido Eicosapentaenoico/metabolismo , Resistencia a la Insulina , Metabolismo de los Lípidos/efectos de los fármacos , Daño por Reperfusión Miocárdica/prevención & control , Compuestos de Amonio Cuaternario/farmacología , Ácido gamma-Aminobutírico/análogos & derivados , Animales , Masculino , Metaboloma , Daño por Reperfusión Miocárdica/etiología , Daño por Reperfusión Miocárdica/metabolismo , Daño por Reperfusión Miocárdica/patología , Ratas , Ratas Zucker , Ácido gamma-Aminobutírico/farmacologíaRESUMEN
Many drug candidates have shown significant renoprotective effects in preclinical models; however, there is no clinically used effective pharmacotherapy for acute kidney injury. The failure to translate from bench to bedside could be due to misleading results from experimental animals with undetected congenital kidney defects. This study was performed to assess the effects of congenital hydronephrosis on the functional capacity of tubular renal transporters as well as kidney sensitivity to ischemia-reperfusion (I-R)-induced injury in male Wistar rats. Ultrasonography was used to distinguish healthy control rats from rats with hydronephrosis. L-carnitine or furosemide was administered, and serial blood samples were collected and analyzed to assess the effects of hydronephrosis on the pharmacokinetic parameters. Renal injury was induced by clamping the renal pedicles of both kidneys for 30 min with subsequent 24 hr reperfusion. The prevalence of hydronephrosis reached ~30%. The plasma concentrations after administration of L-carnitine or furosemide were similar in both groups. I-R induced more pronounced renal injury in the hydronephrotic rats than the control rats, which was evident by a significantly higher kidney injury molecule-1 concentration and lower creatinine concentration in the urine of the hydronephrotic rats than the control rats. After I-R, the gene expression levels of renal injury markers were significantly higher in the hydronephrotic kidneys than in the kidneys of control group animals. In conclusion, our results demonstrate that hydronephrotic kidneys are more susceptible to I-R-induced damage than healthy kidneys. Unilateral hydronephrosis does not affect the pharmacokinetics of substances secreted or absorbed in the renal tubules.
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Lesión Renal Aguda/fisiopatología , Hidronefrosis/fisiopatología , Riñón/irrigación sanguínea , Daño por Reperfusión/fisiopatología , Lesión Renal Aguda/complicaciones , Animales , Carnitina/sangre , Carnitina/orina , Moléculas de Adhesión Celular/metabolismo , Susceptibilidad a Enfermedades , Diuréticos/sangre , Diuréticos/orina , Furosemida/sangre , Furosemida/orina , Hidronefrosis/complicaciones , Riñón/diagnóstico por imagen , Masculino , Ratas , Ratas Wistar , Daño por Reperfusión/complicaciones , UltrasonografíaRESUMEN
Aim: Trimethylamine N-oxide (TMAO) is a gut microbiota-derived metabolite synthesized in host organisms from specific food constituents, such as choline, carnitine and betaine. During the last decade, elevated TMAO levels have been proposed as biomarkers to estimate the risk of cardiometabolic diseases. However, there is still no consensus about the role of TMAO in the pathogenesis of cardiovascular disease since regular consumption of TMAO-rich seafood (i.e., a Mediterranean diet) is considered to be beneficial for the primary prevention of cardiovascular events. Therefore, the aim of this study was to investigate the effects of long-term TMAO administration on mitochondrial energy metabolism in an experimental model of right ventricle heart failure. Methods: TMAO was administered to rats at a dose of 120 mg/kg in their drinking water for 10 weeks. Then, a single subcutaneous injection of monocrotaline (MCT) (60 mg/kg) was administered to induce right ventricular dysfunction, and treatment with TMAO was continued (experimental groups: Control; TMAO; MCT; TMAO+MCT). After 4 weeks, right ventricle functionality was assessed by echocardiography, mitochondrial function and heart failure-related gene and protein expression was determined. Results: Compared to the control treatment, the administration of TMAO (120 mg/kg) for 14 weeks increased the TMAO concentration in cardiac tissues up to 14 times. MCT treatment led to impaired mitochondrial function and decreased right ventricular functional parameters. Although TMAO treatment itself decreased mitochondrial fatty acid oxidation-dependent respiration, no effect on cardiac functionality was observed. Long-term TMAO administration prevented MCT-impaired mitochondrial energy metabolism by preserving fatty acid oxidation and subsequently decreasing pyruvate metabolism. In the experimental model of right ventricle heart failure, the impact of TMAO on energy metabolism resulted in a tendency to restore right ventricular function, as indicated by echocardiographic parameters and normalized organ-to-body weight indexes. Similarly, the expression of a marker of heart failure severity, brain natriuretic peptide, was substantially increased in the MCT group but tended to be restored to control levels in the TMAO+MCT group. Conclusion: Elevated TMAO levels preserve mitochondrial energy metabolism and cardiac functionality in an experimental model of right ventricular heart failure, suggesting that under specific conditions TMAO promotes metabolic preconditioning-like effects.
RESUMEN
PURPOSE: Mildronate and orotic acid act as modulators of energy metabolism and are considered as cardioprotective agents. This study was performed to compare the cardioprotective effects of mildronate, orotic acid and mildronate orotate. METHODS: Male Wistar rats received mildronate, orotic acid or mildronate orotate for 14 days. The isolated rat heart infarction and isoproterenol-induced ischemia models were used to test the cardioprotective effects of compounds studied. Experimental arrhythmias were induced by the ligation of the left anterior descending coronary artery for 10 min with subsequent reperfusion or by administration of calcium chloride or aconitine at arrhythmogenic doses. RESULTS: The data obtained showed a statistically significant decrease of necrotic area in 25% of infarcted rat hearts after 14 days of treatment with mildronate and orotic acid, whereas mildronate orotate decreased the infarct size by 50%. Moreover, we found that the administration of mildronate and its orotate salt decreased the duration and incidence of arrhythmias in experimental arrhythmia models. CONCLUSIONS: The study provides experimental evidence that the combination of orotic acid and mildronate possesses additive pharmacological effects and that mildronate orotate might be considered as a powerful therapeutic agent facilitating recovery from ischemia-reperfusion injury.
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Cardiotónicos/farmacología , Metilhidrazinas/farmacología , Infarto del Miocardio/tratamiento farmacológico , Ácido Orótico/farmacología , Animales , Arritmias Cardíacas/tratamiento farmacológico , Arritmias Cardíacas/fisiopatología , Modelos Animales de Enfermedad , Sinergismo Farmacológico , Quimioterapia Combinada , Masculino , Infarto del Miocardio/fisiopatología , Necrosis/tratamiento farmacológico , Ratas , Ratas Wistar , Daño por Reperfusión/tratamiento farmacológicoRESUMEN
Significant impairments in mitochondrial function are associated with the development of multi-organ failure in sepsis/endotoxaemia, but the data on the dynamics of simultaneous mitochondrial impairment in multiple organs are limited. The aim of this study was to evaluate the changes in heart, brain and kidney mitochondrial function in an experimental model of lipopolysaccharide (LPS)-induced endotoxaemia.Samples were collected 4 and 24âh after single injection of LPS (10âmg/kg) in mice. Marked increases in inflammation-related gene expression were observed in all studied tissues 4âh after LPS administration. At 24âh post LPS administration, this expression of inflammation-related genes remained upregulated only in kidneys. Significantly increased concentrations of kidney function markers confirmed that kidneys were severely damaged. Echocardiographic measurements showed that the ejection fraction and fractional shortening were significantly reduced 4âh after LPS administration, whereas 24âh after LPS administration, the cardiac function was restored to baseline. A two-fold decrease in mitochondrial oxidative phosphorylation (OXPHOS) capacity in the kidney was observed 4 and 24âh after LPS administration. Significant decrease in mitochondrial fatty acid oxidation was observed in heart 4âh after LPS administration. Furthermore, 24âh after LPS administration, the respiration rates in cardiac fibers at OXPHOS and electron transport (ET) states were significantly increased, which resulted in increased ET coupling efficiency in the LPS-treated group, whereas four-fold increases in the H2O2 production rate and H2O2/O ratio were observed. The brain mitochondria demonstrated a slightly impaired mitochondrial functionality just 24âh after the induction of endotoxaemia.In conclusion, among studied tissues kidney mitochondria are the most sensitive to endotoxaemia and do not recover from LPS-induced damage, whereas in brain, mitochondrial function was not significantly altered. In heart, endotoxaemia induces a decrease in the mitochondrial fatty acid oxidation capacity, but during the phase of suppressed inflammatory response, the ET efficiency is improved despite the marked increase in reactive oxygen species production.
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Encéfalo/metabolismo , Endotoxemia/metabolismo , Riñón/metabolismo , Mitocondrias Cardíacas/metabolismo , Miocardio/metabolismo , Animales , Encéfalo/patología , Modelos Animales de Enfermedad , Endotoxemia/inducido químicamente , Endotoxemia/patología , Riñón/patología , Lipopolisacáridos/toxicidad , Masculino , Ratones , Ratones Endogámicos ICR , Mitocondrias Cardíacas/patología , Miocardio/patologíaRESUMEN
Phenibut (3-phenyl-4-aminobutyric acid) is a GABA (gamma-aminobutyric acid)-mimetic psychotropic drug which is clinically used in its racemic form. The aim of the present study was to compare the effects of racemic phenibut and its optical isomers in pharmacological tests and GABAB receptor binding studies. In pharmacological tests of locomotor activity, antidepressant and pain effects, S-phenibut was inactive in doses up to 500 mg/kg. In contrast, R-phenibut turned out to be two times more potent than racemic phenibut in most of the tests. In the forced swimming test, at a dose of 100 mg/kg only R-phenibut significantly decreased immobility time. Both R-phenibut and racemic phenibut showed analgesic activity in the tail-flick test with R-phenibut being slightly more active. An GABAB receptor-selective antagonist (3-aminopropyl)(diethoxymethyl)phosphinic acid (CGP35348) inhibited the antidepressant and antinociceptive effects of R-phenibut, as well as locomotor depressing activity of R-phenibut in open field test in vivo. The radioligand binding experiments using a selective GABAB receptor antagonist [3H]CGP54626 revealed that affinity constants for racemic phenibut, R-phenibut and reference GABA-mimetic baclofen were 177+/-2, 92+/-3, 6.0+/-1 microM, respectively. We conclude that the pharmacological activity of racemic phenibut relies on R-phenibut and this correlates to the binding affinity of enantiomers of phenibut to the GABAB receptor.
Asunto(s)
Psicotrópicos/farmacología , Ácido gamma-Aminobutírico/análogos & derivados , Analgésicos/farmacología , Animales , Antidepresivos/farmacología , Conflicto Psicológico , Depresión/psicología , Agonistas del GABA/farmacología , Antagonistas del GABA/farmacología , Calor , Masculino , Ratones , Ratones Endogámicos CBA , Ratones Endogámicos ICR , Actividad Motora/efectos de los fármacos , Fuerza Muscular/efectos de los fármacos , Compuestos Organofosforados/farmacología , Dimensión del Dolor/efectos de los fármacos , Equilibrio Postural/efectos de los fármacos , Desempeño Psicomotor/efectos de los fármacos , Psicotrópicos/administración & dosificación , Psicotrópicos/química , Tiempo de Reacción/efectos de los fármacos , Receptores de GABA-B/efectos de los fármacos , Estereoisomerismo , Natación/psicología , Ácido gamma-Aminobutírico/administración & dosificación , Ácido gamma-Aminobutírico/química , Ácido gamma-Aminobutírico/farmacologíaRESUMEN
AIMS: l-carnitine has been shown to play a central role in both fat and carbohydrate metabolisms. This study investigated whether acute and long-term treatments with an l-carnitine biosynthesis inhibitor, mildronate (3-(2,2,2-trimethylhydrazinium) propionate), modulate glucose uptake. MAIN METHODS: The effects of acute and long-term administration of mildronate at a dose of 200 mg/kg (i.p. daily for 20 days) were tested in mouse blood plasma and heart. KEY FINDINGS: Acute administration of mildronate in vivo, or in vitro administration with perfusion buffer in isolated heart experiments, did not induce any effects on glucose blood concentration and uptake in the heart. Mildronate long-term treatment significantly decreased carnitine concentration in plasma and heart tissues, as well as increased the rate of insulin-stimulated glucose uptake by 35% and the expression of glucose transporter 4, hexokinase II, and insulin receptor proteins in mouse hearts. In addition, expression of both carnitine palmitoyltransferases IA and IB were significantly increased. Mildronate long-term treatment statistically significantly decreased fed state blood glucose from 6+/-0.2 to 5+/-0.1 mM, but did not affect plasma insulin and C-peptide levels. SIGNIFICANCE: Our experiments demonstrate for the first time that long-term mildronate treatment decreases carnitine content in the mouse heart and leads to increased glucose uptake and glucose metabolism-related gene expression.
Asunto(s)
Carnitina/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Glucosa/metabolismo , Metilhidrazinas/farmacología , Miocardio/metabolismo , Animales , Betaína/análogos & derivados , Betaína/análisis , Péptido C/análisis , Carnitina/análisis , Transportador de Glucosa de Tipo 4/genética , Corazón/efectos de los fármacos , Hexoquinasa/genética , Masculino , Ratones , Ratones Endogámicos ICR , ARN Mensajero/análisis , Regulación hacia ArribaRESUMEN
l-carnitine has a documented role as a cofactor in cellular energy metabolism and fatty acid beta-oxidation pathways and it has also been considered to function in reproductive biology. We investigated whether decreasing concentrations of L-carnitine using an inhibitor of its biosynthesis, mildronate (3-(2,2,2-trimethylhydrazinium)-propionate), would influence the sexual behavior or sperm quality in male rats. Mildronate treatment induced a significant decrease in carnitine concentration and an increase in gamma-butyrobetaine (GBB) concentration in both plasma and testes extracts. However, the expression of carnitine palmitoyltransferase I in testes and testosterone concentration in plasma was not changed in mildronate treated rat. Behavioral experiments demonstrated that mildronate treatment did not decrease the sexual motivation in both sexually naive and sexually experienced rats. The densities of spermatozoa in the cauda epididymis, as well as motility, were unchanged after mildronate treatment at a dose of 100 mg/kg. In conclusion, our study provides experimental evidence that mildronate induces decrease in the free carnitine concentration in rat testes, but does not decrease the sexual activity or sperm quality of male rats.
Asunto(s)
Carnitina/biosíntesis , Conducta Sexual Animal/fisiología , Adyuvantes Inmunológicos/administración & dosificación , Administración Oral , Animales , Conducta Animal/efectos de los fármacos , Betaína/análogos & derivados , Betaína/metabolismo , Carnitina/metabolismo , Cromatografía Liquida/métodos , Quimasas/metabolismo , Relación Dosis-Respuesta a Droga , Masculino , Metilhidrazinas/administración & dosificación , Ratas , Conducta Sexual Animal/efectos de los fármacos , Motilidad Espermática/efectos de los fármacos , Espermatozoides/efectos de los fármacos , Espectrometría de Masas en Tándem/métodos , Testosterona/sangre , Factores de TiempoRESUMEN
Meldonium (3-(2,2,2-trimethylhydrazinium)propionate) is the most potent clinically used inhibitor of organic cation transporter 2 (OCTN2). Inhibition of OCTN2 leads to a decrease in carnitine and acylcarnitine contents in tissues and energy metabolism optimization-related cardioprotective effects. The recent inclusion of meldonium in the World Anti-Doping Agency List of Prohibited Substances and Methods has raised questions about the pharmacokinetics of meldonium and its unusually long elimination time. Therefore, in this study, the rate of meldonium washout after the end of the treatment was tested with and without administration of carnitine, γ-butyrobetaine (GBB) and furosemide to evaluate the importance of competition for OCTN2 transport in mice. Here, we show that carnitine and GBB administration during the washout period effectively stimulated the elimination of meldonium. GBB induced a more pronounced effect on meldonium elimination than carnitine due to the higher affinity of GBB for OCTN2. The diuretic effect of furosemide did not significantly affect the elimination of meldonium, carnitine and GBB. In conclusion, the competition of meldonium, carnitine and GBB for OCTN2-mediated transport determines the pharmacokinetic properties of meldonium. Thus, due to their affinity for OCTN2, GBB and carnitine but not furosemide stimulated meldonium elimination. During long-term treatment, OCTN2-mediated transport ensures a high muscle content of meldonium, while tissue clearance depends on relatively slow diffusion, thus resulting in the unusually long complete elimination period of meldonium.
Asunto(s)
Betaína/análogos & derivados , Carnitina/administración & dosificación , Metilhidrazinas/farmacocinética , Proteínas de Transporte de Catión Orgánico/metabolismo , Animales , Betaína/administración & dosificación , Betaína/farmacocinética , Betaína/farmacología , Transporte Biológico/efectos de los fármacos , Carnitina/farmacocinética , Carnitina/farmacología , Furosemida/administración & dosificación , Furosemida/farmacología , Masculino , Metilhidrazinas/farmacología , Ratones , Proteínas de Transporte de Catión Orgánico/antagonistas & inhibidores , Miembro 5 de la Familia 22 de Transportadores de Solutos , Distribución TisularRESUMEN
Ischaemia in the heart is accompanied by the accumulation of long-chain acylcarnitines (LCACs) which is one of the multiple factors that contribute to the ischaemia-reperfusion damage development. Long-term pre-treatment that decreases carnitine and LCAC contents also reduces ischaemia-reperfusion (IR) damage; however, the duration of the post-treatment effects is not known. The aim of the study was to assess the post-treatment effects of the carnitine transport (OCTN2) inhibitor, methyl-GBB, on LCAC content and the duration of its cardioprotective effect. Male Wistar rats received methyl-GBB (5 mg/kg for 28 days), and the anti-infarction effects on Langendorff-perfused hearts and the acylcarnitine profile in cardiac tissues were measured up to 28 days following the end of the treatment. Methyl-GBB pre-treatment for 28 days decreased LCAC heart tissue content by 87%, and the infarct size was decreased by 57%. Fourteen days post-treatment, the LCAC content was still decreased by 69%, and the infarct size was decreased by 32% compared to Control. A significant Pearson correlation (r = 0.48, p = 0.026) was found between infarct size and LCAC tissue content in the methyl-GBB-treated rat hearts. The addition of 2 mM carnitine to isolated heart perfusate significantly diminished the methyl-GBB-induced decrease in LCACs and infarct size. In conclusion, the anti-infarction effect of methyl-GBB continues for at least 2 weeks post-treatment. No less than a 70% decrease in LCAC content is required to protect ischaemic heart tissues, and the decrease in LCAC levels defines the duration of the post-treatment cardioprotective effect of the OCTN2 inhibitor, methyl-GBB.