AIM: To demonstrate and discuss the pros and cons of various conventional and innovative analytical approaches. Methodology & results: Matrix-assisted laser desorption/ionization mass spectrometry imaging (MSI) of tissue sections as well as the extraction of tissue homogenates, blood plasma and dried blood spots coupled with LC-MS were employed to monitor the pharmacokinetics of metformin in mice. The time profile of metformin measured by matrix-assisted laser desorption/ionization MSI correlated well with the results found by LC-MS. Repeatability of the preparation of tissue sections for MSI was very good. CONCLUSION: MSI provided valuable information on the spatial distribution and relative concentration of the analyte within tissue sections. The analysis of the extracts of tissue homogenates, blood plasma and blood spots provided quantitative data on metformin. The dried blood spot approach is a progressive method of sampling, especially in studies where the amount of available blood is limited.
- MeSH
- chromatografie kapalinová metody MeSH
- lidé MeSH
- metformin farmakokinetika MeSH
- myši MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice metody MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Obesity and type 2 diabetes mellitus (T2DM) were characterized as risk factors for Alzheimer's disease (AD) development. Subsequently, T2DM drugs, such as liraglutide, were proven to be neuroprotective compounds attenuating levels of amyloid deposits, and tau hyperphosphorylation, both hallmarks of AD. The central anorexigenic effects of liraglutide inspired us to examine the potential neuroprotective effects of palm11-PrRP31, a strong anorexigenic analog with glucose-lowering properties, in THY-Tau22 mice overexpressing mutated human tau, a model of AD-like tau pathology. Seven-month-old THY-Tau22 mice were subcutaneously infused with palm11-PrRP31 for 2 months. Spatial memory was tested before and after the treatment, using a Y-maze. At the end of the treatment, mice were sacrificed by decapitation and hippocampi were dissected and analyzed by immunoblotting with specific antibodies. Treatment with palm11-PrRP31 resulted in significantly improved spatial memory. In the hippocampi of palm11-PrRP31-treated THY-Tau22 mice, tau protein phosphorylation was attenuated at Thr231, Ser396, and Ser404, the epitopes linked to AD progression. The mechanism of this attenuation remains unclear, since the activation of those kinases most implicated in tau hyperphosphorylation, such as GSK-3β, JNK, or MAPK/ERK1/2, remained unchanged by palm11-PrRP31 treatment. Furthermore, we observed a significant increase in the amount of postsynaptic density protein PSD95, and a non-significant increase of synaptophysin, both markers of increased synaptic plasticity, which could also result in improved spatial memory of THY-Tau22 mice treated with palm11-PrRP31. Palm11-PrRP31 seems to be a potential tool for the attenuation of neurodegenerative disorders in the brain. However, the exact mechanism of its action must be elucidated.
- MeSH
- bludiště - učení účinky léků fyziologie MeSH
- fosforylace účinky léků MeSH
- hipokampus účinky léků metabolismus patologie MeSH
- hormon uvolňující prolaktin analogy a deriváty farmakologie terapeutické užití MeSH
- krátkodobá paměť účinky léků fyziologie MeSH
- modely nemocí na zvířatech MeSH
- myši transgenní MeSH
- neuroprotektivní látky farmakologie MeSH
- poruchy paměti farmakoterapie metabolismus patologie MeSH
- prostorová paměť účinky léků fyziologie MeSH
- proteiny tau metabolismus MeSH
- tauopatie farmakoterapie metabolismus patologie psychologie MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND/OBJECTIVES: Prolactin-releasing peptide (PrRP) has a potential to decrease food intake and ameliorate obesity, but is ineffective after peripheral administration. We have previously shown that our novel lipidized analogs PrRP enhances its stability in the circulation and enables its central effect after peripheral application. The purpose of this study was to explore if sub-chronic administration of novel PrRP analog palmitoylated in position 11 (palm11-PrRP31) to Koletsky-spontaneously hypertensive obese rats (SHROB) could lower body weight and glucose intolerance as well as other metabolic parameters. SUBJECTS/METHODS: The SHROB rats (n = 16) were used for this study and age-matched hypertensive lean SHR littermates (n = 16) served as controls. Palm11-PrRP31 was administered intraperitoneally to SHR and SHROB (n = 8) at a dose of 5 mg/kg once-daily for 3 weeks. During the dosing period food intake and body weight were monitored. At the end of the experiment the oral glucose tolerance test was performed; plasma and tissue samples were collected. Thereafter, arterial blood pressure was measured. RESULTS: At the end of the experiment, vehicle-treated SHROB rats showed typical metabolic syndrome parameters, including obesity, glucose intolerance, dyslipidemia, and hypertension. Peripheral treatment with palm11-PrRP31 progressively decreased the body weight of SHR rats but not SHROB rats, though glucose tolerance was markedly improved in both strains. Moreover, in SHROB palm11-PrRP31 ameliorated the HOMA index, insulin/glucagon ratio, and increased insulin receptor substrate 1 and 2 expression in fat and insulin signaling in the hypothalamus, while it had no effect on blood pressure. CONCLUSIONS: We demonstrated that our new lipidized PrRP analog is capable of improving glucose tolerance in obese SHROB rats after peripheral application, suggesting that its effect on glucose metabolism is independent of leptin signaling and body weight lowering. These data suggest that this analog has the potential to be a compound with both anti-obesity and glucose-lowering properties.
- MeSH
- glukagon krev MeSH
- glukózový toleranční test MeSH
- hormon uvolňující prolaktin aplikace a dávkování analogy a deriváty farmakologie terapeutické užití MeSH
- hypertenze krev farmakoterapie MeSH
- inzulin krev metabolismus MeSH
- inzulinová rezistence MeSH
- krevní glukóza metabolismus MeSH
- krevní tlak účinky léků MeSH
- lipidy krev MeSH
- metabolický syndrom * krev farmakoterapie metabolismus MeSH
- mozek účinky léků metabolismus MeSH
- obezita * krev farmakoterapie MeSH
- porucha glukózové tolerance * krev farmakoterapie MeSH
- potkani inbrední SHR MeSH
- proteiny insulinového receptorového substrátu metabolismus MeSH
- tělesná hmotnost účinky léků MeSH
- tuková tkáň účinky léků metabolismus MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
AIM: Novel compounds for obesity treatment are currently being studied employing lipidized analogs of anorexigenic neuropeptides. Various analogs of prolactin-releasing peptide have demonstrated their ability to decrease food intake. Adequate analytical tools are required to support corresponding research. Methodology & results: An analytical method was developed that includes simple dilution of plasma samples prior to liquid chromatography-mass spectrometry and employs a monolithic column for the determination of lipidized analogs of prolactin-releasing peptide in complex biological samples. A multiple reaction monitoring approach was applied that included matrix calibration and an internal standard and produced a linear calibration range 20-200 ng ml-1 in rat and macaque plasma samples. CONCLUSION: A straightforward, simple and reliable analytical method was developed satisfying major validation criteria.
- MeSH
- biochemická analýza krve metody MeSH
- chromatografie kapalinová metody MeSH
- hormon uvolňující prolaktin krev chemie MeSH
- kalibrace MeSH
- krysa rodu rattus MeSH
- lipidy chemie MeSH
- metody pro přípravu analytických vzorků * MeSH
- sekvence aminokyselin MeSH
- tandemová hmotnostní spektrometrie metody MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
A number of novel lipopeptides have been studied for their possible therapeutic potential. These studies should be supported by the appropriate analytical tools not only for novel potential drugs but also for their metabolites, precursors and side products. Lipopeptides have specific physicochemical properties that make them successful in medical applications. However, there are some difficulties with their qualitative and quantitative analyses in biological samples. Therefore, reliable, sensitive and robust analytical methods are in high demand. The main interest of our review is to describe a selection of specific and important properties of lipopeptides, and the analytical methods currently utilized for their characterization and determination in biological samples. A comparison of the pros and cons of immunomethods versus LC-MS methods is discussed in detail.
- MeSH
- extrakce na pevné fázi MeSH
- ghrelin analýza izolace a purifikace MeSH
- hmotnostní spektrometrie * MeSH
- imunoanalýza * MeSH
- lidé MeSH
- lipopeptidy analýza izolace a purifikace MeSH
- vazba proteinů MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Jana Zemenová talks to Sankeetha Nadarajah, Commissioning Editor: Jana is a PhD student of analytical chemistry in her final year at the University of Chemistry and Technology, Prague. She also works at the Institute of Organic Chemistry and Biochemistry of Czech Academy of Sciences, in the group led by Lenka Maletínská. She has obtained her MSc in Analysis of Drugs and continues working at University of Chemistry and Technology Prague under the supervision of David Sýkora.
In our project, ghrelin analogs possessing enhanced stability and potential to significantly increase food intake were used. Three newly synthesized ghrelin analogs with fatty acid residues consisting of 8, 10, and 14 carbon atoms were studied. The main goal of this work was to develop a suitable analytical method for the determination of the stability of the novel ghrelin analogs in plasma. An appropriate liquid chromatography-mass spectrometry method was developed and optimized. The results obtained were compared with the data measured by using a commercial enzyme-linked immunosorbent assay kit, and a good correlation was found. A preparation strategy for plasma samples was optimized and consisted of simple dilution of the plasma samples followed by direct injection onto a very short monolithic column in combination with mass spectrometric detection. The developed analytical method was utilized for the determination of the stability of the prepared lipopeptides in plasma and for the quantification of the lipopeptides in a preliminary pharmacokinetic study. The feasibility of the developed separation method was clearly demonstrated. Accuracy and precision were within 80-120% and ±20% limits, respectively. Calibration curves were constructed in the range of 1-250 μg/mL.
Obesity is an escalating epidemic, but an effective non-invasive therapy is still scarce. For obesity treatment, anorexigenic neuropeptides are promising tools, but their delivery from the periphery to the brain is complicated by their peptide character. In order to overcome this unfavorable fact, we have applied the lipidization of neuropeptide prolactin-releasing peptide (PrRP), whose strong anorexigenic effect was demonstrated. A palmitoylated analog of human PrRP (h palm-PrRP31) was injected in free-fed Wistar rats by three routes: subcutaneous (s.c.), intraperitoneal (i.p) (both 5 mg/kg) and intravenous (i.v.) (from 0.01 to 0.5 mg/kg). We found a circulating compound in the blood after all three applications with the highest concentration after i.v. administration. This corresponds to the effect on food intake, which was also strongest after i.v. injection. Moreover, this is in agreement with the fact that the expression of c-Fos in specific brain regions involved in food intake regulation was also highest after intravenous application. Pharmacokinetic data are further supported by results obtained from dynamic light scattering and CD spectroscopy. Human palm-PrRP31 analog showed a strong tendency to micellize, and formation of aggregates suggested lower availability after i.p. or s.c. application. We have demonstrated that palm-PrRP influenced food intake even in free fed rats. Not surprisingly, the maximal effect was achieved after the intravenous application even though two orders of magnitude lower dose was used compared to both two other applications. We believe that palm-PrRP could have a potential as an antiobesity drug when its s.c. application would be improved.
- MeSH
- CHO buňky MeSH
- Cricetulus MeSH
- energetický příjem účinky léků MeSH
- hormon uvolňující prolaktin aplikace a dávkování analogy a deriváty metabolismus farmakokinetika MeSH
- křečci praví MeSH
- krysa rodu rattus MeSH
- látky proti obezitě aplikace a dávkování metabolismus farmakokinetika MeSH
- lidé MeSH
- mozek metabolismus MeSH
- neurony účinky léků metabolismus MeSH
- obezita farmakoterapie MeSH
- peptidové fragmenty aplikace a dávkování metabolismus farmakokinetika MeSH
- preklinické hodnocení léčiv MeSH
- protoonkogenní proteiny c-fos metabolismus MeSH
- receptory spřažené s G-proteiny metabolismus MeSH
- vazba proteinů MeSH
- zvířata MeSH
- Check Tag
- křečci praví MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Obesity is an escalating epidemic, but an effective noninvasive therapy is still scarce. For obesity treatment, anorexigenic neuropeptides are promising tools, but their delivery from the periphery to the brain is complicated because peptides have a low stability and limited ability to cross the blood-brain barrier. In this review, we summarize results of several studies with our newly designed lipidized analogs of prolactin-releasing peptide (PrRP). PrRP is involved in feeding and energy balance regulation as demonstrated by obesity phenotypes of both PrRP- and PrRP-receptor-knockout mice. Lipidized PrRP analogs showed binding affinity and signaling in PrRP receptor-expressing cells similar to natural PrRP. Moreover, these analogs showed high binding affinity also to anorexigenic neuropeptide FF (NPFF)-2 receptor. Acute peripheral administration of myristoylated and palmitoylated PrRP analogs to mice and rats induced strong and long-lasting anorexigenic effects and neuronal activation in the brain areas involved in food intake regulation. Two-week-long subcutaneous administration of palmitoylated PrRP31 and myristoylated PrRP20 lowered food intake, body weight, improved metabolic parameters and attenuated lipogenesis in mice with diet-induced obesity. A strong anorexigenic, body weight-reducing and glucose tolerance-improving effect of palmitoylated-PrRP31 was shown also in diet-induced obese rats after its repeated 2-week-long peripheral administration. Thus, the strong anorexigenic and body weight-reducing effects of palmitoylated PrRP31 and myristoylated PrRP20 make these analogs attractive candidates for antiobesity treatment. Moreover, PrRP receptor might be a new target for obesity therapy.
- MeSH
- hormon uvolňující prolaktin analogy a deriváty terapeutické užití MeSH
- látky proti obezitě farmakologie terapeutické užití MeSH
- lékové transportní systémy * MeSH
- lidé MeSH
- obezita farmakoterapie MeSH
- regulace chuti k jídlu * MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Metformin, vildagliptin and their combination are widely used for the treatment of diabetes, but little is known about the metabolic responses to these treatments. In the present study, NMR-based metabolomics was applied to detect changes in the urinary metabolomic profile of a mouse model of diet-induced obesity in response to these treatments. Additionally, standard biochemical parameters and the expression of enzymes involved in glucose and fat metabolism were monitored. Significant correlations were observed between several metabolites (e.g., N-carbamoyl-β-alanine, N1-methyl-4-pyridone-3-carboxamide, N1-methyl-2-pyridone-5-carboxamide, glucose, 3-indoxyl sulfate, dimethylglycine and several acylglycines) and the area under the curve of glucose concentrations during the oral glucose tolerance test. The present study is the first to present N-carbamoyl-β-alanine as a potential marker of type 2 diabetes mellitus and consequently to demonstrate the efficacies of the applied antidiabetic interventions. Moreover, the elevated acetate level observed after vildagliptin administration might reflect increased fatty acid oxidation.
- MeSH
- adamantan analogy a deriváty farmakologie MeSH
- beta-alanin analogy a deriváty metabolismus MeSH
- diabetes mellitus 2. typu farmakoterapie metabolismus moč MeSH
- dieta MeSH
- glukózový toleranční test metody MeSH
- hypoglykemika farmakologie MeSH
- metabolomika metody MeSH
- metformin farmakologie MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- nitrily farmakologie MeSH
- obezita farmakoterapie metabolismus moč MeSH
- pyridony metabolismus MeSH
- pyrrolidiny farmakologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
