Linagliptin, a DPP-4 inhibitor, activates AMPK/FOXO3a and suppresses NFκB to mitigate the debilitating effects of diethylnitrosamine exposure in rat liver: Novel mechanistic insights.

Accumulating evidence suggests that dysregulation of FOXO3a plays a significant role in the progression of various malignancies, including hepatocellular carcinoma (HCC). FOXO3a inactivation, driven by oncogenic stimuli, can lead to abnormal cell growth, suppression of apoptosis, and resistance to anticancer drugs. Therefore, FOXO3a emerges as a potential molecular target for the development of innovative treatments in the era of oncology. Linagliptin (LNGTN), a DPP-4 inhibitor known for its safe profile, has exhibited noteworthy anti-inflammatory and anti-oxidative properties in previous in vivo studies. Several potential molecular mechanisms have been proposed to explain these effects. However, the capacity of LNGTN to activate FOXO3a through AMPK activation has not been investigated. In our investigation, we examined the potential repurposing of LNGTN as a hepatoprotective agent against diethylnitrosamine (DENA) intoxication. Additionally, we assessed LNGTN's impact on apoptosis and autophagy. Following a 10-week administration of DENA, the liver underwent damage marked by inflammation and early neoplastic alterations. Our study presents the first experimental evidence demonstrating that LNGTN can reinstate the aberrantly regulated FOXO3a activity by elevating the nuclear fraction of FOXO3a in comparison to the cytosolic fraction, subsequent to AMPK activation. Moreover, noteworthy inactivation of NFκB induced by LNGTN was observed. These effects culminated in the initiation of apoptosis, the activation of autophagy, and the manifestation of anti-inflammatory, antiproliferative, and antiangiogenic outcomes. These effects were concomitant with improved liver function and microstructure. In conclusion, our findings open new avenues for the development of novel therapeutic strategies targeting the AMPK/FOXO3a signaling pathway in the management of chronic liver damage.

Linagliptin decreased the tumor progression on glioblastoma model.

PURPOSE: Dipeptidyl peptidase-4 (DPP-4) inhibitors are oral hypoglycemic drugs and are used for type II diabetes. Previous studies showed that DPP-4 expression is observed in several tumor types and DPP-4 inhibitors suppress the tumor progression on murine tumor models. In this study, we evaluated the role of DPP-4 and the antitumor effect of a DPP-4 inhibitor, linagliptin, on glioblastoma (GBM). METHODS: We analyzed DPP-4 expression in glioma patients by the public database. We also analyzed DPP-4 expression in GBM cells and the murine GBM model. Then, we evaluated the cell viability, cell proliferation, cell migration, and expression of some proteins on GBM cells with linagliptin. Furthermore, we evaluated the antitumor effect of linagliptin in the murine GBM model. RESULTS: The upregulation of DPP-4 expression were observed in human GBM tissue and murine GBM model. In addition, DPP-4 expression levels were found to positively correlate with the grade of glioma patients. Linagliptin suppressed cell viability, cell proliferation, and cell migration in GBM cells. Linagliptin changed the expression of phosphorylated NF-kB, cell cycle, and cell adhesion-related proteins. Furthermore, oral administration of linagliptin decreases the tumor progression in the murine GBM model. CONCLUSION: Inhibition of DPP-4 by linagliptin showed the antitumor effect on GBM cells and the murine GBM model. The antitumor effects of linagliptin is suggested to be based on the changes in the expression of several proteins related to cell cycle and cell adhesion via the regulation of phosphorylated NF-kB. This study suggested that DPP-4 inhibitors could be a new therapeutic strategy for GBM.

Network-based drug repositioning of linagliptin as a potential agent for uterine fibroids targeting transforming growth factor-beta mediated fibrosis.

Uterine fibroid is the most common non-cancerous tumor with no satisfactory options for long-term pharmacological treatment. Fibroblast activation protein-α (FAP) is one of the critical enzymes that enhances the fibrosis in uterine fibroids. Through STITCH database mining, we found that dipeptidyl peptidase-4 inhibitors (DPP4i) have the potential to inhibit the activity of FAP. Both DPP4 and FAP belong to the dipeptidyl peptidase family and share a similar catalytic domain. Hence, ligands which have a binding affinity with DPP4 could also bind with FAP. Among the DPP4i, linagliptin exhibited the highest binding affinity (Dock score = -8.562 kcal/mol) with FAP. Our study uncovered that the differences in the S2 extensive-subsite residues between DPP4 and FAP could serve as a basis for designing selective inhibitors specifically targeting FAP. Furthermore, in a dynamic environment, linagliptin was able to destabilize the dimerization interface of FAP, resulting in potential inhibition of its biological activity. True to the in-silico results, linagliptin reduced the fibrotic process in estrogen and progesterone-induced fibrosis in rat uterus. Furthermore, linagliptin reduced the gene expression of transforming growth factor-ß (TGF-ß), a critical factor in collagen secretion and fibrotic process. Masson trichrome staining confirmed that the anti-fibrotic effects of linagliptin were due to its ability to reduce collagen deposition in rat uterus. Altogether, our research proposes that linagliptin has the potential to be repurposed for the treatment of uterine fibroids.

Linagliptin mitigates cisplatin-induced kidney impairment via mitophagy regulation in rats, with emphasis on SIRT-3/PGC-1α, PINK-1 and Parkin-2.

Cisplatin (CDDP) often leads to kidney impairment, limiting its effectiveness in cancer treatment. The lack of mitophagy in proximal tubules exacerbates this issue. Hence, targeting SIRT-3 and PGC1-α shows promise in mitigating CDDP-induced kidney damage. The potential renoprotective effects of linagliptin, however, remain poorly understood. This study represents the first exploration of linagliptin's impact on CDDP-induced kidney impairment in rats, emphasizing its potential role in mitophagic pathways. The experiment involved four rat groups: Group (I) received saline only, Group (II) received a single intraperitoneal injection of CDDP at 6 mg/kg. Groups (III) and (IV) received linagliptin at 6 and 10 mg/kg p.o., respectively, seven days before CDDP administration, continuing for an additional four days. Various parameters, including renal function tests, oxidative stress, TNF-α, IL-1ß, IL-6, PGC-1α, FOXO-3a, p-ERK1, and the gene expression of SIRT-3 and P62 in renal tissue, were assessed. Linagliptin improved renal function, increased antioxidant enzyme activity, and decreased IL-1ß, TNF-α, and IL-6 expression. Additionally, linagliptin significantly upregulated PGC-1α and PINK-1/Parkin-2 expression while downregulating P62 expression. Moreover, linagliptin activated FOXO-3a and SIRT-3, suggesting a potential enhancement of mitophagy. Linagliptin demonstrated a positive impact on various factors related to kidney health in the context of CDDP-induced impairment. These findings suggest a potential role for linagliptin in improving cancer treatment outcomes. Clinical trials are warranted to further investigate and validate its efficacy in a clinical setting.

Linagliptin Mitigates TGF-ß1 Mediated Epithelial-Mesenchymal Transition in Tacrolimus-Induced Renal Interstitial Fibrosis via Smad/ERK/P38 and HIF-1α/LOXL2 Signaling Pathways.

The dipeptidyl peptidase-4 (DPP-4) inhibitors, a novel anti-diabetic medication family, are renoprotective in diabetes, but a comparable benefit in chronic non-diabetic kidney diseases is still under investigation. This study aimed to elucidate the molecular mechanisms of linagliptin's (Lina) protective role in a rat model of chronic kidney injury caused by tacrolimus (TAC) independent of blood glucose levels. Thirty-two adult male Sprague Dawley rats were equally randomized into four groups and treated daily for 28 d as follows: The control group; received olive oil (1 mL/kg/d, subcutaneously), group 2; received Lina (5 mg/kg/d, orally), group 3; received TAC (1.5 mg/kg/d, subcutaneously), group 4; received TAC plus Lina concomitantly in doses as the same previous groups. Blood and urine samples were collected to investigate renal function indices and tubular injury markers. Additionally, signaling molecules, epithelial-mesenchymal transition (EMT), and fibrotic-related proteins in kidney tissue were assessed by enzyme-linked immunosorbent assay (ELISA) and Western blot analysis, immunohistochemical and histological examinations. Tacrolimus markedly induced renal injury and fibrosis as indicated by renal dysfunction, histological damage, and deposition of extracellular matrix (ECM) proteins. It also increased transforming growth factor ß1 (TGF-ß1), Smad4, p-extracellular signal-regulated kinase (ERK)1/2/ERK1/2, and p-P38/P38 mitogen-activated protein kinase (MAPK) protein levels. These alterations were markedly attenuated by the Lina administration. Moreover, Lina significantly inhibited EMT, evidenced by inhibiting Vimentin and α-smooth muscle actin (α-SMA) and elevating E-cadherin. Furthermore, Lina diminished hypoxia-related protein levels with a subsequent reduction in Snail and Twist expressions. We concluded that Lina may protect against TAC-induced interstitial fibrosis by modulating TGF-ß1 mediated EMT via Smad-dependent and independent signaling pathways.

Linagliptin's impact on lymphatic barrier and lymphangiogenesis in oral cancer with high glucose.

OBJECTIVES: Uncertainties remain regarding the effect of elevated glucose levels on lymphatic metastasis of cancer cells. Our study elucidated the mechanisms linking high glucose to lymphangiogenesis and lymphatic barrier-related factors and investigated the protective role of linagliptin against lymphatic barrier dysfunction. MATERIALS AND METHODS: A CAL-27-LEC co-culture system was established. Sodium fluorescein permeability assay observed lymphatic endothelial cell permeability. Western blotting and RT-qPCR detected protein and mRNA expression under different conditions, respectively. CCK-8, scratch wound healing, and transwell assays revealed cell migration and proliferation. Tube formation experiment tested capacity for endothelial tube formation. Immunohistochemical staining analyzed tissue sections from 43 oral cancer individuals with/without diabetes. RESULTS: In high-glucose co-culture system, we observed increased lymphatic barrier permeability and decreased expression of ZO-1 and occludin, two tight-junction proteins; conversely, the expression of PAR2, a high permeability-related protein, was increased. Following linagliptin treatment, the expression levels of VEGF-C, VEGFR-3, and PAR2 decreased, while those of ZO-1 and occludin increased. Considerably higher levels of LYVE-1 expression in individuals with diabetes than in those without diabetes. CONCLUSIONS: By ameliorating the high glucose-induced disruption of the lymphatic endothelial barrier, linagliptin may reduce lymphangiogenesis and exhibit an inhibitory effect on lymphatic metastasis in oral cancer patients with diabetes.

Identification and Structural Characterization of Degradation Products of Linagliptin by Mass Spectrometry Techniques.

As part of the development and production of pharmaceuticals, the purity of Active Pharmaceutical Ingredients stands as a fundamental parameter that significantly influences the quality, safety, and efficacy of the final drug product. Impurities in Active Pharmaceutical Ingredients are various unwanted substances that can appear during the whole manufacturing process, from raw materials to the final product. These impurities can stem from multiple sources, including starting materials, intermediates, reagents, solvents, and even degradation products resulting from exposure to environmental factors such as heat, light, or moisture. Their presence can potentially compromise the therapeutic effect of the drug, introduce unexpected side effects, or even pose safety risks to patients. This study aims to conduct the forced degradation of linagliptin and subsequently attempt to identify the resulting degradants. The degradation procedures were carried out in accordance with the guidelines of the International Committee for Harmonization. The degradation profile of linagliptin was investigated under various conditions, including acid hydrolysis, alkaline hydrolysis, oxidation, heat, and light exposure, utilizing ultra-performance liquid chromatography connected to a photo array detector. Identification and characterization of the degradation products were achieved using an ultra-performance liquid chromatography coupled with a single quadrupole detector mass spectrometer and also a liquid chromatography coupled with a high-resolution mass spectrometry. The identified degradation products demonstrate that linagliptin is particularly susceptible to degradation when exposed to acid and peroxide. Whereas, no significant degradation effects were observed under alkali, thermolytic, and photolytic conditions.

Acute and Chronic Exposure to Linagliptin, a Selective Inhibitor of Dipeptidyl Peptidase-4 (DPP-4), Has an Effect on Dopamine, Serotonin and Noradrenaline Level in the Striatum and Hippocampus of Rats.

Linagliptin is a selective dipeptidyl peptidase-4 (DPP-4) inhibitor that indirectly elevates the glucagon-like peptide-1 (GLP-1) level. The aim of the present study was to check whether linagliptin has an influence on neurotransmission in rat brain. Rats were acutely and chronically exposed to linagliptin (10 and 20 mg/kg, intraperitoneally (i.p.)). Twenty-four hours later, the striatum and hippocampus were selected for further studies. In neurochemical experiments, using high-performance liquid chromatography with electrochemical detection (HPLC-ED), the concentrations of three major neurotransmitters-dopamine, serotonin and noradrenaline-and their metabolites were measured. The analysis of mRNA expression of dopamine (D1 and D2), serotonin (5-HT-1 and 5-HT-2) and noradrenaline (α1 and α2a) receptors was also investigated using real-time quantitative reverse transcription polymerase chain reaction (RQ-PCR) in the same brain areas. Linagliptin has the ability to influence the dopaminergic system. In the striatum, the elevation of dopamine and its metabolites was observed after repeated administration of that linagliptin, and in the hippocampus, a reduction in dopamine metabolism was demonstrated. Acute linagliptin exposure increases the serotonin level in both areas, while after chronic linagliptin administration a tendency for the mRNA expression of serotoninergic receptors (5-HT1A and 5-HT2A) to increase was observed. A single instance of exposure to linagliptin significantly modified the noradrenaline level in the striatum and intensified noradrenaline turnover in the hippocampus. The recognition of the interactions in the brain between DPP-4 inhibitors and neurotransmitters and/or receptors is a crucial step for finding novel discoveries in the pharmacology of DPP-4 inhibitors and raises hope for further applications of DPP-4 inhibitors in clinical practices.

Safety of Linagliptin in Patients with Type 2 Diabetes Mellitus: A Systematic Review and Meta-analysis of Randomized Clinical Trials.

BACKGROUND: Linagliptin is an oral dipeptidyl peptidase DPP-4 inhibitor, which is indicated for the treatment of Type 2 diabetes mellitus (T2DM) as monotherapy or add-on to therapy with other hypoglycemic drugs. OBJECTIVES: We aimed to summarize the evidence from randomized controlled trials (RCTs) to assess the safety of linagliptin focusing on cardiovascular risks among subjects with type 2 diabetes mellitus. METHODS: We conducted a systematic search across the following databases: Medline, Embase, the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov from inception to November 2021. Randomized controlled trials (RCTs) of linagliptin compared to placebo in patients with Type 2 diabetes were included. The primary safety points were cardiovascular (CV) adverse events including non-fatal stroke, non-fatal myocardial infarction (MI), CV death, MI, stroke, and hospitalization for unstable angina. While, secondary safety points included 17 reported adverse events such as infections, hypoglycemia and abdominal pain. Three reviewers independently screened and reviewed each study to extract relevant information. Any discrepancies were resolved by consensus. We conducted a meta-analysis using the random effects model. Pooled risk ratios (RRs) of targeted adverse events with linagliptin compared to placebo were estimated using the Mantel-Haenszel test. RESULTS: A total of 24 studies with 19,981 adult patients were included. There was no difference in the incidence of all CV adverse events or individual CV adverse events between linagliptin and the placebo arms. The pooled estimate of the risk of upper respiratory tract infection was reported in twelve trials with a 38% risk reduction among patients treated with the linagliptin group compared to the placebo group (RR = 0.62, 95% CI: 0.45-0.85, and I2 = 0%), while no difference was found in other infections. For gastrointestinal disorders, the risk of abdominal pain showed a 65% risk reduction among patients treated with the linagliptin group compared to the placebo group (RR = 0.35, 95% CI: 0.16-0.77, and I2 = 0%). CONCLUSION: Our study showed an overall acceptable safety profile of linagliptin in patients with T2DM. Moreover, our study showed a risk reduction of upper respiratory tract infection and abdominal pain when using linagliptin compared to placebo.

Development of eco-friendly spectrophotometric methods for analysis of metformin hydrochloride and linagliptin in presence of metformin toxic impurity in their pure and dosage forms: Validation, practicality and greenness studies.

Metformin is considered as type 2 diabetes first line treatment according to American Diabetes Association and European Association. But, in some cases, di- or tri - therapy should be prescribed for glycemic management, prevention of the maximum dose side effects and induced effectiveness. Co-administration of Linagliptin with metformin has many benefits on diabetic patients such as decrease the possibility of hypoglycemia. For the first time, novel and reliable techniques were developed and verified for the concurrent quantification of metformin hydrochloride and linagliptin, while accounting for the existence of metformin toxic impurity 1-cyanoguanidine in their pure and dosage forms. Method (A) utilizes the zero-order spectrophotometric approach to quantitatively determine the concentration of linagliptin. The measurements are performed at a wavelength of 295 nm. The double divisor derivative ratio spectrophotometric method is used in Method (B) to measure the amounts of metformin and cyanoguanidine at 252 nm and 219 nm wavelengths, respectively. The spectrophotometric method (C) for determining metformin and cyanoguanidine at 252 nm and 223 nm, respectively, is based on the single divisor derivative ratio-zero crossing technique. The obtained findings were subjected to statistical comparison with the reported method, revealing no statistically significant differences. The Green Analytical Procedure Index (GAPI) and Analytical GREEnness Metric approach (AGREE) determined that these approaches had a high degree of environmental friendliness. Additionally, the proposed strategy was deemed to be practical according to the Blue Applicability Grade Index (BAGI) assessment tool.

Evaluating the Efficacy, Safety, and Tolerability of Combination Therapy of Dapagliflozin and Linagliptin Over Dapagliflozin and Vildagliptin in Patients With Type 2 Diabetes Mellitus Inadequately Controlled With Metformin.

Background Type 2 diabetes mellitus (T2DM) patients commonly undergo metformin monotherapy. This study aims to compare the efficacy, safety, and tolerability of combination therapy of dapagliflozin plus linagliptin versus dapagliflozin plus vildagliptin as add-on therapy in T2DM patients inadequately controlled on metformin. Methodology This was an 18-week, multicenter, randomized, double-blind, active-controlled, parallel-group, phase III clinical study. About 236 participants were randomly assigned to receive either a fixed-dose combination of dapagliflozin 10 mg plus linagliptin 5 mg tablets or a fixed-dose combination of dapagliflozin 10 mg plus vildagliptin SR 100 mg tablets added to metformin monotherapy. The primary outcome was the mean change in hemoglobin A1c (HbA1c) from baseline to the end of week 16. The key secondary endpoints were mean change in postprandial blood glucose (PPBG), fasting blood glucose (FBG), body weight, and the proportion of participants achieving HbA1c less than 7.0%. Results The dapagliflozin/linagliptin combination therapy showed a more significant change in HbA1c from baseline to the end of 16 weeks (mean reduction: -1.59% vs. -1.25%) compared to dapagliflozin/vildagliptin (p < 0.0001). Additionally, compared to the dapagliflozin/vildagliptin group, the dapagliflozin/linagliptin group demonstrated a significant reduction in both PPBG (mean reduction: -59.99 mg/dL vs. -55.34 mg/dL) and FPG (mean reduction: -32.91 mg/dL vs. -26.78 mg/dL). A total of 18 adverse events were reported in 17 (7.20%) participants, all of which were mild and resolved completely. There were no serious adverse events. Conclusions Compared to dapagliflozin and vildagliptin combination therapy, dapagliflozin and linagliptin fixed-dose combination provided clinically significant improvements in glycemic control. Because of its effectiveness, safety, and tolerability, the fixed-dose combination of dapagliflozin and linagliptin was a better option for treating T2DM patients who had previously only received metformin monotherapy.

Water in nigella oil microemulsion for enhanced oral bioavailability of linagliptin.

Linagliptin is hydrophilic antidiabetic with poor oral bioavailability due to poor permeability and pre-systemic metabolism. The objective was to assess w/o microemulsion for enhanced oral bioavailability of linagliptin. Nigella oil was used as oily phase based on its reported antidiabetic effect. Isopropyl myristate (IPM) or capryol were combined with nigella oil to impart intestinal membrane permeabilizing abilities. Pseudoternary phase diagrams were constructed utilizing nigella oil in presence and absence of isopropyl myristate or capryol as oily phase using Tween 60 as surfactant. W/O microemulsion formulations were selected from the constructed phase diagrams and linagliptin was loaded in the internal aqueous phase at a concentration of 0.5 mg/ml. The prepared formulations were physically evaluated and linagliptin in vitro release was monitored. Eventually, the in vivo hypoglycemic effect was assessed using diabetic rats. The developed microemulsions were of w/o type and exhibited Newtonian flow behavior with nigella/capryol microemulsion recording the lowest viscosity. The recorded droplet size values were 104.9, 121.2 and 86.4 nm for nigella, nigella/IPM and nigella/capryol microemulsions, respectively. All microemulsion formulations showed slower drug release rate compared with aqueous suspension with nigella/capryol microemulsion showing the highest release rate compared to other microemulsions. Release data from microemulsion best fitted to Higuchi model. In vivo oral hypoglycemic activity measurement reflected a more intensified hypoglycemic effect with rapid onset after oral ingestion of microemulsion compared to linagliptin dispersion. Nigella oil/IPM-based microemulsion was ranked as the most effective. The investigation highlighted the feasibility of w/o microemulsion for enhanced oral bioavailability of hydrophilic drugs like linagliptin.

Effect of metformin and metformin/linagliptin on gut microbiota in patients with prediabetes.

Lifestyle modifications, metformin, and linagliptin reduce the incidence of type 2 diabetes (T2D) in people with prediabetes. The gut microbiota (GM) may enhance such interventions' efficacy. We determined the effect of linagliptin/metformin (LM) vs metformin (M) on GM composition and its relationship to insulin sensitivity (IS) and pancreatic ß-cell function (Pßf) in patients with prediabetes. A cross-sectional study was conducted at different times: basal, six, and twelve months in 167 Mexican adults with prediabetes. These treatments increased the abundance of GM SCFA-producing bacteria M (Fusicatenibacter and Blautia) and LM (Roseburia, Bifidobacterium, and [Eubacterium] hallii group). We performed a mediation analysis with structural equation models (SEM). In conclusion, M and LM therapies improve insulin sensitivity and Pßf in prediabetics. GM is partially associated with these improvements since the SEM models suggest a weak association between specific bacterial genera and improvements in IS and Pßf.

Summary of Research: Efficacy and Safety of the SGLT2 Inhibitor Empagliflozin Versus Placebo and the DPP-4 Inhibitor Linagliptin Versus Placebo in Young People with Type 2 Diabetes (DINAMO): A Multicentre, Randomised, Double-Blind, Parallel Group, Phase 3 Trial.

The increasing occurrence of childhood overweight and obesity has been followed by a substantial increase in youth-onset type 2 diabetes (T2D). Pharmacological treatment options for youth-onset T2D remain limited, with a clear unmet need for additional oral agents. This summary of research reports on the efficacy and safety of empagliflozin and linagliptin on glycaemic control in children and adolescents aged 10-17 years with T2D in the randomised, double-blind, parallel group, phase 3 DINAMO trial. Empagliflozin provided a clinically relevant, statistically significant, and durable improvement in glycaemic control; however, linagliptin did not. The safety profile of both empagliflozin and linagliptin was comparable to those observed in studies in adults. These results suggest that empagliflozin could be a new oral therapy option for youth-onset T2D.

Transdermal Drug Delivery System of Linagliptin Sustained-release Microparticle Gels: In vitro Characterization and In vivo Evaluation.

BACKGROUND: Linagliptin (LNG) exhibits poor bioavailability and numerous side effects, significantly limiting its use. Transdermal drug delivery systems (TDDS) offer a potential solution to overcome the first-pass effect and gastrointestinal reactions associated with oral formulations. OBJECTIVE: The aim of this study was to develop LNG microparticle gels to enhance drug bioavailability and mitigate side effects. METHODS: Linagliptin hyaluronic acid (LNG-HA) microparticles were prepared by spray drying method and their formulation was optimized via a one-factor method. The solubility and release were investigated using the slurry method. LNG-HA microparticle gels were prepared and optimised using in vitro transdermal permeation assay. The hypoglycaemic effect of the LNG-HA microparticle gel was examined on diabetic mice. RESULTS: The results indicated that the LNG-HA microparticle encapsulation rate was 84.46%. Carbomer was selected as the gel matrix for the microparticle gels. Compared to the oral API, the microparticle gel formulation demonstrated a distinct biphasic release pattern. In the first 30 minutes, only 43.56% of the drug was released, followed by a gradual release. This indicates that the formulation achieved a slow-release effect from a dual reservoir system. Furthermore, pharmacodynamic studies revealed a sustained hypoglycemic effect lasting for 48 hours with the LNG microparticle gel formulation. CONCLUSION: These findings signify that the LNG microparticle gel holds significant clinical value for providing sustained release and justifies its practical application.

DPP-4 inhibition by linagliptin ameliorates age-related mild cognitive impairment by regulating microglia polarization in mice.

Extensive preclinical evidence demonstrates a causative link between insulin signaling dysfunction and the pathogenesis of Alzheimer's disease (AD), and diabetic drugs may represent a promising approach to fighting AD. However, it remains to be determined which antidiabetic drugs are more effective in preventing cognitive impairment. Thus, the present study investigated the effect of dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin on cognitive impairment in middle-aged mice by comparing it with the effect of metformin. We found that DPP-4 activity increased in the hippocampus of middle-aged mice, and DPP-4 was mainly expressed by microglia rather than astrocytes and oligodendrocytes. DPP-4 directly regulated M1/M2 microglia polarization following LPS or IL-4 stimulation, while DPP-4 inhibitor, linagliptin, suppressed M1-polarized activation and induced M2-polarized activation. Both linagliptin and metformin enhanced cognitive ability, increased hippocampal synaptic plasticity and neurogenesis, and decreased age-related oxidative stress and inflammation by regulating microglia polarization in the hippocampus of middle-aged mice. The combination of linagliptin and metformin showed a maximum protective effect compared to the individual drugs alone. Loss of macrophage inflammatory protein-1α (MIP-1α), a DPP-4 substrate, abrogated the cognitive protection and anti-inflammation effects of linagliptin. Therefore, the current investigation exhibits a potential utility for DPP-4 inhibition in attenuating microglia-mediated inflammation and preventing mild cognitive impairment (MCI) in middle-aged mice, and the effect was partly mediated by MIP-1α.

Effects of pioglitazone and linagliptin on glycemic control, lipid profile and hs-CRP in metformin-treated patients with type 2 diabetes: a comparative study.

OBJECTIVES: The purpose of this study was to compare the effects of pioglitazone and linagliptin on glycemic control, lipid profile and high-sensitivity C-reactive protein (hs-CRP) parameters in patients with type 2 diabetes treated with metformin. METHODS: The present randomized clinical trial was conducted on 60 patients with type 2 diabetes treated with metformin in the age range of 30-60 years. The participants with informed consent were randomly assigned to receive pioglitazone or linagliptin. The first intervention group (n=30) received 30 mg of pioglitazone daily and the second intervention group (n=30) received 5 mg of linagliptin daily for 12 weeks. Fasting blood samples were taken from patients at the baseline and after 12 weeks to measure related variables. The current study was approved in Kashan University of Medical Sciences (with the code of ethics of IR.KAUMS.MEDNT.REC.1398.016), and the Iranian Registry of Clinical Trials (with the registration number of IRCT20170513033941N66). RESULTS: The linagliptin administration significantly reduced serum levels of fasting blood sugar (p=0.03), blood sugar 2 h after a meal (p=0.02), glycosylated hemoglobin (p=0.02) and hs-CRP (p=0.005) after 12 weeks compared with pioglitazone. In contrast, the pioglitazone administration significantly decreased triglyceride levels (p=0.01) and increased HDL-cholesterol (p=0.002) compared to linagliptin. In addition, the administration of both linagliptin and pioglitazone drugs had no significant effect on LDL-cholesterol, total cholesterol, systolic and diastolic blood pressure, creatinine and blood urea. CONCLUSIONS: The present study demonstrated the superiority of linagliptin over pioglitazone for glycemic control, although pioglitazone compared to linagliptin showed greater efficacy in reducing triglycerides and raising HDL-cholesterol.

[Linagliptin improves diabetic kidney disease in rats by promoting mitochondrial biogenesis through the AMPK/PGC-1α/TFAM pathway].

OBJECTIVE: To investigate whether linagliptin improves diabetic kidney disease (DKD) by promoting mitochondrial biosynthesis via activating adenosine monophosphate activated protein kinase/peroxisome proliferator-activated receptor gamma coactivator 1α/mitochondrial transcription factor A (AMPK/PGC-1α/TFAM) pathway. METHODS: With 6 male SD rats feeding normal chow as the control group, 16 SD rat models of DKD induced by intraperitoneal injection of 45 mg/kg STZ and high-fat and high-glucose feeding for 4 weeks were randomized into DKD model group and linagliptin treatment group. The rats in the latter two groups were subjected to daily intragastric administration of vehicle or 5 mg/kg linagliptin (dissolved in 5 g/L sodium carboxymethylcellulose, final concentration of 2 mg/mL) for 12 weeks with further high-fat and high-glucose feeding. After the treatments, the rats were sacrificed and blood samples from the abdominal aorta and kidney tissues were collected for testing blood glucose, liver function and lipid metabolism; HE, PAS, Masson, Sirius red staining and electron microscopy were used to observe renal tissue damage. Renal expressions of transforming growth factor ß1 (TGF-ß1), fibronectin (FN) and collagen I (Col I) were detected by immunohistochemistry, and the changes in membrane potential (ΔψM) and ATP enzyme content were analyzed to assess mitochondrial damage; The expressions of AMPK/PGC-1α/TFAM pathway proteins were detected using Western blotting. RESULTS: Compared with DKD model rats, the rats receiving linagliptin treatment showed significantly decreased blood glucose level (P < 0.01) and improved proteinuria (P < 0.05) with obviously alleviated renal ultrastructural damage and fibrosis, increased ATPase content and ΔψM (P < 0.0001), and enhanced renal expressions of P-AMPK/AMPK, PGC-1α and TFAM (P < 0.05). CONCLUSIONS: Linagliptin improves proteinuria and renal fibrosis in rat models of DKD possibly by activating the AMPK/PGC-1α/TFAM pathway to promote mitochondrial biosynthesis.

Interactions of linagliptin, rabeprazole sodium, and their formed complex with bovine serum albumin: Computational docking and fluorescence spectroscopic methods.

The foremost aim of this thermodynamic study was to evaluate the pharmacokinetics (PK) and pharmacodynamics (PD) profiles of linagliptin (LG), rabeprazole sodium (RS), and their 1:1 formed complex by interacting with bovine serum albumin (BSA) at physiological pH 7.4. The molecular interactions of these ligands with the desired biomolecule were substantiated by the spectral quelling of fluorescence intensity of BSA. The fluorescent test and molecular docking revealed that the quenching mechanism was a spontaneous and exothermic static process, and the protein gained its secondary structure due to the interactions. The spectroscopic method was exercised to determine the thermodynamic factors that supported the interactions mediated by van der Waals forces and hydrogen bonds. The activation energy of the formed complex was higher than its precursor drugs while interacting with BSA, and the energy transformation profiles were studied by UV-fluorescence overlaid curves according to Förster resonance energy transfer (FRET) theory. The double log plot verified that these ligands bound with protein at a 1:1 ratio, which was confirmed by the approximately estimated values of the binding parameters. The drastically lower value of the binding constant of the formed complex suggested the lower half-life as well as its triggered elimination rate from the cardiovascular system, which may be an initial indicator of the reduced hypoglycemic property of linagliptin. Moreover, the UV-vis and synchronous fluorescence spectroscopic methods affirmed the conformational changes of the BSA due to drug-protein complexation and polarity alterations in the microenvironment of disparate chromophores of the biomolecule.

Effect of Linagliptin versus Metformin on Insulin Secretion, Insulin Sensitivity and Glucose Control in Subjects with Impaired Glucose Tolerance / Efecto de la Linagliptina Frente a la Metformina en la Secreción de Insulina, Sensibilidad a la Insulina y Control de la Glucosa en Sujetos con Intolerancia a la Glucosa

ABSTRACT Aim: The aim of the study is to evaluate the effect of linagliptin versus metformin on insulin secretion, insulin sensitivity and glucose control in patients with impaired glucose tolerance (IGT). Patients and methods: A randomized, double-blind, clinical trial with parallel groups was per-formed on 16 adults with IGT. Lipid profile and haemoglobin (HbA1c) were evaluated prior to and after the intervention. Glucose and insulin were measured at 0, 30, 60, 90 and 120 minutes after a 75-g oral dextrose load. Eight patients received metformin (500 mg) twice a day before meals for three months. The remaining eight patients received placebo (500 mg) in the morning and linagliptin (5 mg) in the evening before meals. The area under the curve (AUC) of glucose and insulin, total insulin secretion, first-phase of insulin secretion, and insulin sensitivity were assessed. Results: After linagliptin administration, a significant decrease in glucose at 90 minutes (10.8 ± 2.6 vs 7.9 ± 2.2 mmol/L, p < 0.05), 120 minutes (8.8 ± 0.9 vs 6.5 ± 2.1 mmol/L, p < 0.05) and AUC of glucose (1168 ± 210 vs 953 ± 207 mmol/L, p < 0.05) were observed. Metformin administration decreased insulin significantly at 0 minutes (94.8 ± 25.8 vs 73.8 ± 24.6 pmol/L, p < 0.05). Conclusion: Three-month administration of linagliptin in patients with IGT decreased glucose at 90 and 120 minutes after a 75-g oral dextrose load and AUC of glucose. Metformin decreased insulin at 0 minutes.

RESUMEN Objetivo: El objetivo del estudio es evaluar el efecto de la linagliptina frente a la metformina en la secreción de insulina, la sensibilidad a la insulina, y el control de la glucosa en pacientes con intolerancia a la glucosa (IG). Pacientes y métodos: Se realizó un ensayo clínico aleatorio de doble ciego con grupos paralelos a 16 adultos con IG. El perfil lipídico y la hemoglobina (Hba1C) se evaluaron antes y después de la intervención. La glucosa y la insulina se midieron a los 0, 30, 60, 90 y 120 minutos después de un carga oral de 75-g dextrosa. Ocho pacientes recibieron metformina (500 mg) dos veces al día antes de las comidas por tres meses. Los ocho pacientes restantes recibieron placebo (500 mg) por la mañana y linagliptina (5 mg) por la noche antes de las comidas. El área bajo la curva (ABC) de la glucosa y la insulina, la secreción total de insulina, la primera fase de la secreción de insulina, y la sensibilidad a la insulina, fueron evaluadas. Resultados: Luego de la administración de la linagliptina, se observó una disminución significativa de la glucosa a los 90 minutos (10.8 ± 2.6 vs 7.9 ± 2.2 mmol/L, p < 0.05), 120 minutos (8.8 ± 0.9 mmol/L p < 0.05) y el ABC de la glucosa (1168 ± 210 vs 953 ± 207 mmol/L, p < 0.05). La administración de metformina redujo significativamente la insulina a los 0 minutos (94.8 ± 25.8 vs 73.8 ± 24.6 pmol/L, p < 0.05). Conclusión: Tres meses de administración de linagliptina en pacientes con IG disminuyó la glucosa a los 90 y 120 minutos después de una carga oral de dextrosa de 75-g y el ABC de la glucosa. La metformina disminuyó la insulina en 0 minutos.