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Background and Objective Patients with type 2 diabetes mellitus often have impaired renal function or may have impaired hepatic function, which can pose significant safety and tolerability issues for anti-hyperglycaemic pharmacotherapies. Therefore, the pharmacokinetics and tolerability of saxagliptin and its pharmacologically active metabolite, 5-hydroxy saxagliptin, in nondiabetic subjects with mild, moderate or severe renal or hepatic impairment, or end-stage renal disease (ESRD) were compared with saxagliptin and metabolite pharmacokinetics and tolerability in healthy adult subjects. Methods Two open-label, parallel-group, single-dose studies were conducted. Subjects received a single oral dose of saxagliptin 10 mg (Onglyza™). Results Compared with healthy subjects, the geometric mean area under the plasma concentration-time curve from time zero extrapolated to infinity (AUC ∞ ) for saxagliptin was 16%, 41% and 108% (2.1-fold) higher in subjects with mild, moderate or severe renal impairment, respectively. AUC ∞ values for 5-hydroxy saxagliptin were 67%, 192% (2.9-fold) and 347% (4.5-fold) higher in subjects with mild, moderate or severe renal impairment, respectively. As creatinine clearance (CL CR ) values decreased, saxagliptin and 5-hydroxy saxagliptin AUC ∞ generally increased or became more variable. Twenty-three percent of the saxagliptin dose (measured as the sum of saxagliptin and 5-hydroxy saxagliptin) was cleared by haemodialysis in a 4-hour dialysis session. In the hepatic impairment study, the differences in exposure to saxagliptin and 5-hydroxy saxagliptin were less than 2-fold across all groups. As compared with healthy subjects matched for age, bodyweight, sex and smoking status, the AUC ∞ values for saxagliptin were 10%, 38% and 77% higher in subjects with mild, moderate or severe hepatic impairment, respectively. These values were 22%, 7% and 33% lower, respectively, for 5-hydroxy saxagliptin compared with matched healthy subjects. Conclusions One-half the usual dose of saxagliptin 5mg (i.e. 2.5 mg orally once daily) is recommended for patients with moderate (CL CR 30–50 mL/min) or severe (CL CR <30 mL/min not on dialysis) renal impairment or ESRD, but no dose adjustment is recommended for those with mild renal impairment or any degree of hepatic impairment.

Peptidoglycan is an essential structural component of the cell wall in the majority of bacteria, but the obligate intracellular human pathogen Chlamydia trachomatis was thought to be one of the few exceptions; here a click chemistry approach is used to label peptidoglycan in replicating C. trachomatis with novel d -amino acid dipeptide probes. The chlamydial anomaly resolved The sugar amino acid polymer peptidoglycan is an essential cell-wall component in most free-living bacteria. The Chlamydiales, Gram-negative parasites including the human pathogen Chlamydia trachomatis , were thought to be a rare exception: they encode genes for peptidoglycan biosynthesis and are susceptible to β -lactam antibiotics, yet attempts to detect chlamydial peptidoglycans had failed. Now this paradox, known as the 'chlamydial anomaly', has been resolved. This study, using a novel click chemistry technique to label peptidoglycans with D -amino acid dipeptide probes, demonstrates the presence of peptidoglycans in replicating C. trachomatis . Peptidoglycan (PG), an essential structure in the cell walls of the vast majority of bacteria, is critical for division and maintaining cell shape and hydrostatic pressure 1 . Bacteria comprising the Chlamydiales were thought to be one of the few exceptions. Chlamydia harbour genes for PG biosynthesis 2 , 3 , 4 , 5 , 6 , 7 and exhibit susceptibility to ‘anti-PG’ antibiotics 8 , 9 , yet attempts to detect PG in any chlamydial species have proven unsuccessful (the ‘chlamydial anomaly’ 10 ). We used a novel approach to metabolically label chlamydial PG using d -amino acid dipeptide probes and click chemistry. Replicating Chlamydia trachomatis were labelled with these probes throughout their biphasic developmental life cycle, and the results of differential probe incorporation experiments conducted in the presence of ampicillin are consistent with the presence of chlamydial PG-modifying enzymes. These findings culminate 50 years of speculation and debate concerning the chlamydial anomaly and are the strongest evidence so far that chlamydial species possess functional PG.

The investigation of collagen hydrolysates (CHs) is essential due to their widespread use in health, cosmetic, and therapeutic industries, attributing to the presence of bioactive dipeptides (DPs) and tripeptides (TPs). This study developed a novel targeted liquid chromatography–tandem mass spectrometry (LC-MS/MS) method with propyl chloroformate (PCF) derivatization to measure three bioactive peptides—Hydroxyprolyl-glycine (Hyp-Gly), Glycyl-prolyl-hydroxyproline (Gly-Pro-Hyp), and Prolyl-hydroxyproline (Pro-Hyp)—in CHs, with strong correlation coefficients (0.992, 1.000, and 0.995, respectively) and low limits of detection (LODs) of 1.40, 0.14, and 1.16 µM, respectively. Untargeted data-dependent acquisition (DDA) analyses measured peptide size distribution, while amino acid analysis assessed nutritional content. The analysis of ten commercial CHs revealed similar amino acid profiles but varied peptide lengths, indicating diverse hydrolysis conditions. Products with higher proportions of smaller peptides showed elevated levels of the targeted bioactive peptides, suggesting that a smaller peptide size may increase bioactivity. These findings can inform the optimization of CH supplements, providing consumers with detailed peptide content for more informed choices. Data are available via ProteomeXchange with the identifier PXD051699.

Background: Amino acids have a central role in cell metabolism, and intracellular changes contribute to the pathogenesis of various diseases, while the role and specific organ distribution of dipeptides is largely unknown. Method: We established a sensitive, rapid and reliable UPLC-MS/MS method for quantification of 36 dipeptides. Dipeptide patterns were analyzed in brown and white adipose tissues, brain, eye, heart, kidney, liver, lung, muscle, sciatic nerve, pancreas, spleen and thymus, serum and urine of C57BL/6N wildtype mice and related to the corresponding amino acid profiles. Results: A total of 30 out of the 36 investigated dipeptides were detected with organ-specific distribution patterns. Carnosine and anserine were most abundant in all organs, with the highest concentrations in muscles. In liver, Asp-Gln and Ala-Gln concentrations were high, in the spleen and thymus, Glu-Ser and Gly-Asp. In serum, dipeptide concentrations were several magnitudes lower than in organ tissues. In all organs, dipeptides with C-terminal proline (Gly-Pro and Leu-Pro) were present at higher concentrations than dipeptides with N-terminal proline (Pro-Gly and Pro-Leu). Organ-specific amino acid profiles were related to the dipeptide profile with several amino acid concentrations being related to the isomeric form of the dipeptides. Aspartate, histidine, proline and serine tissue concentrations correlated with dipeptide concentrations, when the amino acids were present at the C- but not at the N-terminus. Conclusion: Our multi-dipeptide quantification approach demonstrates organ-specific dipeptide distribution. This method allows us to understand more about the dipeptide metabolism in disease or in healthy state.

The identification of anticancer peptides (ACPs) is crucial, especially in the development of peptide-based cancer therapy. The classical models such as Split Amino Acid Composition (SAAC) and Pseudo Amino Acid Composition (PseAAC) lack the incorporation of feature representation. These advancements improve the predictive accuracy and efficiency of ACP identification. Thus, the effort of this research is to propose and develop an advanced framework based on feature extraction. Thus, to achieve this objective herein we propose an Extended Dipeptide Composition (EDPC) framework. The proposed EDPC framework extends the dipeptide composition by considering the local sequence environment information and reforming the CD-HIT framework to remove noise and redundancy. To measure the accuracy, we have performed several experiments. These experiments were employed using four famous machine learning (ML) algorithms named; Support Vector Machine (SVM), Decision Tree (DT), Random Forest (RF), and K Nearest Neighbor (KNN). For comparisons, we have used accuracy, specificity, sensitivity, precision, recall, and F1-Score as evaluation criteria. The reliability of the proposed framework is further evaluated using statistical significance tests. As a result, the proposed EDPC framework exhibited enhanced performance than SAAC and PseAAC, where the SVM model delivered the highest accuracy of 96. 6% and significant enhancements in specificity, sensitivity, precision, and F1-score over multiple datasets. Due to the incorporation of enhanced feature representation and the incorporation of local and global sequence profiles proposed EDPC achieves higher classification performance. The proposed frameworks can deal with noise and also duplicating features. These are accompanied by a wide range of feature representations. Finally, our proposed framework can be used for clinical applications where ACP identification is essential. Future works will include extending to a larger variety of datasets, incorporating tertiary structural information, and using deep learning techniques to improve the proposed EDPC.

Point mutations of the NADP⁺-dependent isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) occur early in the pathogenesis of gliomas. When mutated, IDH1 and IDH2 gain the ability to produce the metabolite (R)-2-hydroxyglutarate (2HG), but the downstream effects of mutant IDH1 and IDH2 proteins or of 2HG on cellular metabolism are unknown. We profiled >200 metabolites in human oligodendroglioma (HOG) cells to determine the effects of expression of IDH1 and IDH2 mutants. Levels of amino acids, glutathione metabolites, choline derivatives, and tricarboxylic acid (TCA) cycle intermediates were altered in mutant IDH1- and IDH2-expressing cells. These changes were similar to those identified after treatment of the cells with 2HG. Remarkably, N-acetyl-aspartyl-glutamate (NAAG), a common dipeptide in brain, was 50-fold reduced in cells expressing IDH1 mutants and 8.3-fold reduced in cells expressing IDH2 mutants. NAAG also was significantly lower in human glioma tissues containing IDH mutations than in gliomas without such mutations. These metabolic changes provide clues to the pathogenesis of tumors associated with IDH gene mutations.

Diphenylalanine(FF)-Zn self-assembly (FS) confined in covalent organic polymers (FS@COPs) with efficient fluorescence was synthesized for fluorescence sensing of biogenic amines, which was one of the most important indicators for monitoring food freshness. FS@COPs combined excellent biodegradability of self-assembled dipeptide with chemical stability, porosity and targeted site recognition of COPs. With an optimal excitation wavelength of 360 nm and an optimal emission wavelength of 450 nm, FS@COPs could be used as fluorescence probes to rapidly visualize and highly sensitive determination of tryptamine (Try) within 15 min, and the linear range was from 40 to 900 μg L −1 with a detection limit of 63.08 μg kg −1 . Importantly, the FS@COPs showed a high fluorescence quantum yield of 11.28%, and good stability, solubility, and selectivity, which could successfully achieve the rapid, accurate and highly sensitive identification of Try. Furthermore, we revealed the mechanism of FS@COPs for fluorescence sensing of targets. The FS@COPs system was applied to the fluorescence sensing of Try in real samples and showed satisfactory accuracy of 93.02%-105.25%.

Environmentally benign and straightforward spectrophotometric methods were developed and validated for the simultaneous determination of saxagliptin (SAX), metformin (MET), and the pharmacopeial impurity of MET, melamine (MEL), in bulk powder and pharmaceutical formulations. These proposed approaches provide reliable, low-cost, and accessible alternatives to conventional chromatographic techniques, which often require complex instrumentation, extended analysis times, and significant solvent consumption. Two complementary spectrophotometric methods were established. Method A, the ratio-difference approach, utilized MEL as a divisor for the quantification of SAX, while SAX served as a divisor for determining MET and MEL. Method B, based on the first derivative of ratio spectra, applied MEL as a divisor under optimized conditions (scaling factor = 10, Δλ = 4 nm). However, MEL could not be quantified by Method B because its derivative ratio signals in the selected spectral region were too weak and overlapped extensively with those of SAX and MET, preventing the establishment of a reliable linear calibration curve for this impurity. The methods exhibited linearity over the ranges of 5–90 µg/mL for SAX, 1–40 µg/mL for MET, and 0.5–10 µg/mL for MEL. Validation in accordance with ICH Q2(R1) guidelines confirmed their accuracy, precision, selectivity, and specificity. The results obtained by the proposed methods were statistically compared with those of a reported RP‑HPLC method, confirming the reliability of the proposed procedures. The environmental impact was assessed using the principles of green analytical chemistry (GAC), which incorporates sustainability by promoting methods that limit hazardous reagents, reduce energy consumption, and minimize waste while maintaining suitable analytical performance. Holistic evaluation tools such as the analytical greenness metric (AGREE), the green analytical procedure index (GAPI), the national environmental methods index (NEMI), the blue applicability grade index (BAGI), and the RGB 12 model enable simultaneous assessment of analytical quality, environmental impact, and practical applicability. These tools foster the development of “white” analytical chemistry and complement emerging indices like the environmental and practical performance index (EPPI).Overall, these spectrophotometric approaches represent sustainable, efficient, and accessible analytical alternatives for the routine quality control of Saxagliptin and Metformin in combined pharmaceutical formulations.

Phenylketonuria and tyrosinemia type 1 are treated with dietary phenylalanine (Phe) restriction. Aspartame is a Phe-containing synthetic sweetener used in many products, including many ‘regular’ soft drinks. Its amount is (often) not declared; therefore, patients are advised not to consume aspartame-containing foods. This study aimed to determine the variation in aspartame concentrations and its Phe-containing degradation products in aspartame-containing soft drinks. For this, an LC–MS/MS method was developed for the analysis of aspartame, Phe, aspartylphenylalanine, and diketopiperazine in soft drinks. In total, 111 regularly used soft drinks from 10 European countries were analyzed. The method proved linear and had an inter-assay precision (CV%) below 5% for aspartame and higher CVs% of 4.4–49.6% for the degradation products, as many concentrations were at the limit of quantification. Aspartame and total Phe concentrations in the aspartame-containing soft drinks varied from 103 to 1790 µmol/L (30–527 mg/L) and from 119 to 2013 µmol/L (20–332 mg/L), respectively, and were highly variable among similar soft drinks bought in different countries. Since Phe concentrations between drinks and countries highly vary, we strongly advocate the declaration of the amount of aspartame on soft drink labels, as some drinks may be suitable for consumption by patients with Phe-restricted diets.

Several studies suggest that low birthweight resulting from restricted intrauterine growth can leave a metabolic footprint which may persist into adulthood. To investigate this, we performed metabolomic profiling on 5036 female twins, aged 18-80, with weight at birth information available from the TwinsUK cohort and performed independent replication in two additional cohorts. Out of 422 compounds tested, 25 metabolites associated with birthweight in these twins, replicated in 1951 men and women from the Hertfordshire Cohort Study (HCS, aged 66) and in 2391 men and women from the North Finland Birth 1986 cohort (NFBC, aged 16). We found distinct heterogeneity between sexes and, after adjusting for multiple tests and heterogeneity, two metabolites were reproducible overall (propionylcarnitine and 3-4-hydroxyphenyllactate). Testing women only, we found other metabolites associated with lower birthweight from the meta-analysis of the three cohorts (2-hydroxy-butyric acid and γ-glutamylleucine). Higher levels of all these metabolites can be linked to insulin resistance, oxidative stress or a dysfunction of energy metabolism, suggesting that low birthweight in both twins and singletons are having an impact on these pathways in adulthood.