Choosing a gliptin

Designing of xanthine-based DPP-4 inhibitors: a structure-guided alignment dependent Multifacet 3D-QSAR modeling, and molecular dynamics simulation study

The DPP-4 enzyme degrades incretin hormones GLP-1 and GIP. DPP-4 inhibitors are found effective in the prevention of the degradation of incretins. Xanthine scaffold-bearing molecules are reported as potential DPP-4 inhibitors for treating type 2 diabetes mellitus, e.g. the marketed drug linagliptin. In this work, structure-guided alignment-dependent atom- and Gaussian field-based 3D-QSAR have been performed on a dataset of 75 molecules. The robustness and predictive ability of the developed multifacet 3D-QSAR models were validated on different statistical parameters and found to be statistically fit. The favorable and unfavorable pharmacophoric features were mapped for each multifacet 3D-QSAR model based on three alignment sets (1-3). A five-point common pharmacophore hypothesis was generated separately for each set of alignments. The molecular dynamics simulations (up to 100 ns) were performed for the potent molecule from each alignment set (Compounds 12, 40 and 57) compared to reference standard linagliptin to study the binding energy and stability of target-ligand complexes. The MM-PBSA calculations revealed that the binding free energy and stability of compounds 12 (-40.324 ± 17.876 kJ/mol), 40 (-80.543 ± 21.782 kJ/mol) and 57 (-50.202 ± 16.055 kJ/mol) were better than the reference drug linagliptin (-20.390 ± 63.200 kJ/mol). The generated contour maps from structure-guided alignment-dependent multifacet 3D-QSAR models offer information about the structure-activity relationship (SAR) and ligand-target binding energy and stability data from MD simulation may be utilized to design and develop target selective xanthine-based novel DPP-4 inhibitors.Communicated by Ramaswamy H. Sarma.

Comparison of teneligliptin and other gliptin-based regimens in addressing insulin resistance and glycemic control in type 2 diabetic patients: a cross-sectional study

INTRODUCTION

The objective of this study was to compare the effects of teneligliptin-based regimens and other gliptin-based regimens with respect to insulin resistance and glycemic control in patients with type 2 diabetes mellitus (T2DM).

METHODS

We enrolled T2DM subjects, inadequately controlled with metformin and glimepiride and taking one of the gliptins, and divided them into two groups, i.e. group 1 (teneligliptin-based regimens) and group 2 (other gliptin-based regimens). Fasting plasma insulin, adiponectin levels, homeostatic model assessment for insulin resistance (HOMA-IR), glycated hemoglobin (HbA1c), and fasting blood glucose (FBG) were measured and compared. Costs of different gliptins were noted, and mean cost of per day therapy was compared.

RESULTS

Eighty-six subjects participated in this study (43 each in group 1 and group 2). No significant differences were observed in FBG, HbA1c, insulin levels, and HOMA-IR, but the trend was in favor of teneligliptin-based regimens. A significantly higher number of subjects achieved HbA1c target in group 1 (P < 0.001). Teneligliptin had significantly lower cost of per day therapy as compared to other dipeptidyl peptidase-4 inhibitors.

CONCLUSION

Teneligliptin seems to be cost-effective and safer option in T2DM subjects who were not adequately controlled with metformin and sulfonylureas. However, further prospective studies are needed.

Finding the most cost-effective option from commonly used Dipeptidyl peptidase-4 inhibitors in India: a systematic study

OBJECTIVE

To identify a preferred and cost-effective drug among Dipeptidyl peptidase-4 inhibitors (DPP4Is) for Indian patients with T2DM.

METHODS

We performed a systematic literature search using standard databases for relevant literature. Original studies comparing the efficacy and/or safety of different DPP4Is were included. Two authors independently performed the literature search, screening, and collected relevant data from the selected studies. The costs of all brands of individual DPP4Is were noted and compared for lowest, highest, and average cost. Finally, we summarized the information with respect to Efficacy, safety, suitability, and cost to find the most cost-effective DPP4I.

RESULTS

We found 13 eligible studies containing data on 15,720 subjects. These studies showed similar efficacy (or better) and safety with teneligliptin as compared to other DPP4Is. Teneligliptin also showed additional benefits other than the glycemic control. The average cost per tablet of teneligliptin 20 mg was markedly lower as compared to sitagliptin, vildagliptin, and other commonly used DPP4Is. Teneligliptin also outscored other commonly used DPP4Is in India in suitability and seems to have better patient compliance.

CONCLUSIONS

Teneligliptin 20 mg could be considered as the preferred and most cost-effective agent among commonly used DPP4Is for the effective management of patients with T2DM in India.

Exploring the molecular mechanism of linagliptin in osteosarcoma cell lines for anti-cancer activity

BACKGROUND

Finding new applications for widely used current drugs is a fast and effective technique for discovering new anticancer chemicals. Osteosarcoma (OS), the most prevalent form of bone cancer, has several side effects that significantly lower patients' quality of life. This study aims to systematically examine the anti-cancer activity of linagliptin (LG) in the osteosarcoma cell line Saos-2.

METHODS

MTT assays and flow cytometry were used to assess cell viability and apoptosis, respectively. qPCR array experiments were carried out to determine target gene expressions and explain the molecular mechanism of LG's action.

RESULTS

Linagliptin treatment significantly decreased the viability of Saos-2 cells and hFOB1.19 cells (p < 0.001). The treatment also induced increased apoptotic effects in both Saos-2 cells (p < 0.001) and hFOB1.19 cells (p < 0.05). qPCR assays were conducted to assess cancer pathway analysis after applying specific quantities of LG to Saos-2 and hFOB1.19 cells.

CONCLUSION

The findings of this study demonstrate that LG inhibits the proliferation of Saos-2 cells and induces cell death. LG supports cell death by suppressing the expression of specific genes involved in cancer pathways.

DPP-4 inhibitors for treating T2DM - hype or hope? an analysis based on the current literature

DPP-4 inhibition is an interesting line of therapy for treating Type 2 Diabetes Mellitus (T2DM) and is based on promoting the incretin effect. Here, the authors have presented a brief appraisal of DPP-4 inhibitors, their modes of action, and the clinical efficiency of currently available drugs based on DPP-4 inhibitors. The safety profiles as well as future directions including their potential application in improving COVID-19 patient outcomes have also been discussed in detail. This review also highlights the existing queries and evidence gaps in DPP-4 inhibitor research. Authors have concluded that the excitement surrounding DPP-4 inhibitors is justified because in addition to controlling blood glucose level, they are good at managing risk factors associated with diabetes.

Lisinopril prevents bullous pemphigoid induced by dipeptidyl peptidase 4 inhibitors via the Mas receptor pathway

Recent studies have suggested that dipeptidyl peptidase 4 (DPP4) inhibitors increase the risk of development of bullous pemphigoid (BP), which is the most common autoimmune blistering skin disease; however, the associated mechanisms remain unclear, and thus far, no therapeutic targets responsible for drug-induced BP have been identified. Therefore, we used clinical data mining to identify candidate drugs that can suppress DPP4 inhibitor-associated BP, and we experimentally examined the underlying molecular mechanisms using human peripheral blood mononuclear cells (hPBMCs). A search of the US Food and Drug Administration Adverse Event Reporting System and the IBM^® MarketScan^® Research databases indicated that DPP4 inhibitors increased the risk of BP, and that the concomitant use of lisinopril, an angiotensin-converting enzyme inhibitor, significantly decreased the incidence of BP in patients receiving DPP4 inhibitors. Additionally, in vitro experiments with hPBMCs showed that DPP4 inhibitors upregulated mRNA expression of MMP9 and ACE2, which are responsible for the pathophysiology of BP in monocytes/macrophages. Furthermore, lisinopril and Mas receptor (MasR) inhibitors suppressed DPP4 inhibitor-induced upregulation of MMP9. These findings suggest that the modulation of the renin-angiotensin system, especially the angiotensin1-7/MasR axis, is a therapeutic target in DPP4 inhibitor-associated BP.

Dipeptidyl peptidase-4 (DPP-4) inhibitory activity and glucagon-like peptide (GLP-1) secretion in arsenically safe pigmented red rice (Oryza sativa L.) and its product

Inhibition of DPP-4 and stimulation of GLP-1 secretion are therapeutic strategies for controlling glycaemia in type 2 diabetes. The present study assessed the DPP-4 inhibitory activity and GLP-1 secretory action of pigmented and non-pigmented rice (Oryza sativa L.), along with an extruded food product. Cereal-based extruded food products, with or without passion fruit powder, were prepared from red rice using a twin extruder. Optimal extrusion conditions were determined using a CCD of response surface methodology resulting in optimal conditions to be 97.5 °C, a screw speed of 250 rpm, feed moisture of 25.2% and addition of 11.25% passion fruit powder. Samples were sequentially extracted in n-hexane, ethanol (50%) and water. Ethanol/water (50:50) extracts of rice bran significantly inhibited DPP-4 activity by 70.48 ± 1.06%, comparing favourably with RR (42.55 ± 0.84%), PRR (35.91 ± 1.27%) and PA (29.14 ± 1.23%). DPP-4 inhibitory activity was retained in both extruded products albeit at reduced levels. GLP-1 secretion was stimulated mostly by extruded products extracted with n-hexane or ethanol which upregulated basal secretion by 6.1-fold and 4.2-fold, respectively. ICP-MS results showed that extruded food items have a lower arsenic content. In conclusion, there are potential opportunities for the nutraceuticals and functional food products using pigmented red rice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05444-x.

Natural Compounds as DPP-4 Inhibitors: 3D-Similarity Search, ADME Toxicity, and Molecular Docking Approaches

Type 2 diabetes mellitus is one of the most common diseases of the 21st century, caused by a sedentary lifestyle, poor diet, high blood pressure, family history, and obesity. To date, there are no known complete cures for type 2 diabetes. To identify bioactive natural products (NPs) to manage type 2 diabetes, the NPs from the ZINC15 database (ZINC-NPs DB) were screened using a 3D shape similarity search, molecular docking approaches, and ADMETox approaches. Frequently, in silico studies result in asymmetric structures as “hit” molecules. Therefore, the asymmetrical FDA-approved diabetes drugs linagliptin (8-[(3R)-3-aminopiperidin-1-yl]-7-but-2-ynyl-3-methyl-1-[(4-methylquinazolin-2-yl)methyl]purine-2,6-dione), sitagliptin ((3R)-3-amino-1-[3-(trifluoromethyl)-6,8-dihydro-5H-[1,2,4]triazolo[4,3-a]pyrazin-7-yl]-4-(2,4,5-trifluorophenyl)butan-1-one), and alogliptin (2-[[6-[(3R)-3-aminopiperidin-1-yl]-3-methyl-2,4-dioxopyrimidin-1-yl]methyl]benzonitrile) were used as queries to virtually screen the ZINC-NPs DB and detect novel potential dipeptidyl peptidase-4 (DPP-4) inhibitors. The most promising NPs, characterized by the best sets of similarity and ADMETox features, were used during the molecular docking stage. The results highlight that 11 asymmetrical NPs out of 224,205 NPs are potential DPP-4 candidates from natural sources and deserve consideration for further in vitro/in vivo tests.

A review on phytochemical and pharmacological facets of tropical ethnomedicinal plants as reformed DPP-IV inhibitors to regulate incretin activity

Type 2 diabetes mellitus is a metabolic disorder resulting from impaired insulin secretion and resistance. Dipeptidyl peptidase (DPP)-IV is an enzyme known to trigger the catalysis of insulinotropic hormones, further abating the endogenous insulin levels and elevating the glucose levels in blood plasma. In the field of drug development, DPP-IV inhibitors have opened up numerous opportunities for leveraging this target to generate compounds as hypoglycemic agents by regulating incretin activity and subsequently decreasing blood glucose levels. However, the practice of synthetic drugs is an apparent choice but poses a great pharmacovigilance issue due to their incessant undesirable effects. The ideology was set to inventively look upon different ethnomedicinal plants for their anti-diabetic properties to address these issues. To date, myriads of phytochemicals are characterized, eliciting an anti-diabetic response by targeting various enzymes and augmenting glucose homeostasis. Antioxidants have played a crucial role in alleviating the symptoms of diabetes by scavenging free radicals or treating the underlying causes of metabolic disorders and reducing free radical formation. Plant-based DPP-IV inhibitors, including alkaloids, phenolic acid, flavonoids, quercetin, and coumarin, also possess antioxidant capabilities, providing anti-diabetic and antioxidative protection. This review article provides a new gateway for exploring the ability of plant-based DPP-IV inhibitors to withstand oxidative stress under pathological conditions related to diabetes and for reforming the strategic role of ethnomedicinal plants as potent DPP-IV inhibitors through the development of polyherbal formulations and nanophytomedicines to regulate incretin activity.

Bullous pemphigoid in diabetic patients treated by gliptins: the other side of the coin

Bullous pemphigoid (BP) is the most common autoimmune bullous skin disease that affects primarily patients older than 60 years. The majority of BP cases are spontaneous, but BP can also be triggered by certain drugs’ exposures. Since 2011, a growing number of observations has been reporting cases of BP in Type 2 diabetic patients. These forms have been linked to the use of a new category of anti-diabetic drugs called dipeptidyl peptidase inhibitors (DPP-4i) or gliptins, but to date, the exact pathophysiological mechanisms underlying this association are not completely elucidated. Although conventional and gliptin-associated BP are thought to share similar clinical and histopathological features, our thorough review of the most recent literature, shows that these 2 forms are quite distinct: DPP-4-i-associated BP seems to appear at an earlier age than spontaneous BP, it may manifest either as a noninflammatory or inflammatory phenotype, while the conventional form presents with a typical inflammatory phenotype. Additionally, an important distinctive histological feature was recently shown in Gliptin-associated BP: these forms may present a less significant eosinophils infiltrate in the upper dermis of peri-blister lesions compared to the skin of patients with spontaneous BP, and this seems a specific feature of the clinically non-inflammatory forms. In accordance with previous literature, we found that the direct immunofluorescence (DIF) gives identical findings in both DPP-4i-associated and conventional forms of BP which is an IgG and complement C3 deposition as a linear band at the dermal–epidermal junction in perilesional skin. Indirect immunofluorescence shows the presence of IgG circulating autoantibodies in the patient's serum which titer does not differ between spontaneous and DPP-4i-associated BP, while the specificity of these autoantibodies, may be different in spontaneous, induced non-inflammatory and induced inflammatory forms, epitope spreading phenomenon seems to play a role in determining these specificities. Further research, based on integrated epidemiological, clinical, histo-immunological and pharmacogenomic approaches, may give more insight into these forms of BP. This combined approach will allow to better define BP endotypes and to unveil the mechanism of spontaneous or drug-induced breakage of the immunotolerance to skin self-antigens.

Piperazine sulfonamides as DPP-IV inhibitors: Synthesis, induced-fit docking and in vitro biological evaluation

Diabetes mellitus is a chronic illness that needs persistent medical attention and continuous patient self-management to avoid acute complications. Dipeptidyl peptidase-IV (DPP-IV) inhibitors minimize glucagon and blood glucose levels by increasing the incretin levels, glucagon-like peptide (GLP-1) and glucose-dependent insulinotropic poly-peptide (GIP), leading to insulin secretion from pancreatic beta cells. In the present study, nine 1,4-bis(phenylsulfonyl) piperazine derivatives 1a-i were synthesized and identified using ¹H NMR, ¹³C NMR, MS and IR spectroscopies. These compounds were tested in vitro and showed inhibitory activity ranging from 11.2 to 22.6 % at 100 µmol L^-1 concentration. Piperazine sulfonamide derivatives were found to be promising DPP-IV inhibitors, where the presence of electron-withdrawing groups such as Cl (1a-c) improved the activity of the compounds more than electron-donating groups such as CH_{3 (} 1d-f) at the same position. Additionally, meta-substitution is disfavored (1b, 1e, 1g). Induced-fit docking studies suggested that the targeted compounds 1a-i occupy the binding domain of DPP-IV and form H-bonding with the backbones of R125, E205, E206, F357, K554, W629, Y631, Y662 and R669.

Dipeptidyl peptidase 4 inhibitors attenuate cardiac ischaemia-reperfusion injury in rats with diabetes mellitus type 2

The aim of our study was to assess and compare the effects of dipeptidyl peptidase 4 (DPP4) inhibitors, saxagliptin and sitagliptin, on metabolic control of disease and cardiac function in rats with diabetes mellitus type 2 (T2DM). This research would provide novel understanding into the potentially protective effects of DPP4 inhibitors in helping salvage of the heart exposed to ischaemia-reperfusion (I-R) injury. Forty-eight Wistar albino rats were randomly divided into four groups: CTRL, Control healthy group; T2DM, rats with T2DM; T2DM + Sit, rats with T2DM treated with 0.6 mg/kg of sitagliptin; T2DM + Sax, rats with T2DM treated with 0.45 mg/kg of saxagliptin for 3 weeks. At the end of the protocol, in vivo cardiac function was assessed by echocardiography, while in the blood samples glucose and insulin were determined. Additionally, ex vivo heart function was estimated on a model of I-R injury using Langendorff apparatus. Immunohistochemical analysis was used to determine the degree of myocardial apoptosis and necrosis, while DPP4 staining was performed to assess the cardiac DPP4 expression. Data were analyzed using a one-way analysis of variance (ANOVA) and the post hoc Bonferroni test for multiple comparisons. Improved glycoregulation was noticed in rats that received DPP4 inhibitors compared to untreated diabetic rats (P < .05). Moreover, better in vivo systolic function was observed in rats treated with both DPP4 inhibitors as evidenced by an increase in fractional shortening when compared to T2DM (P < .05). Most parameters of cardiac function in treated rats remained unaltered during reperfusion, thus suggesting that both drugs protected myocardium during flow restoration. Better effects on coronary circulation were achieved after sitagliptin application. Additionally, both DPP4 inhibitors showed similar potential to attenuate cardiac necrosis and apoptosis. Saxagliptin and sitagliptin might be efficient in preserving myocardial function and morphology in ex vivo induced I-R cardiac injury in rats with T2DM.

Teneligliptin Real-World Effectiveness Assessment in Patients with Type 2 Diabetes Mellitus in India: A Retrospective Analysis (TREAT-INDIA 2)

INTRODUCTION

Teneligliptin is an antidiabetic medication that has been approved for the management of type 2 diabetes mellitus (T2DM) in Japan, South Korea and India. It is one of the most commonly prescribed antihyperglycaemic agents. The aim of this study was to assess the effectiveness of teneligliptin in improving glycemic control amongst Indian patients with T2DM in a real-world setting.

METHODS

This was a retrospective observational study in which a predesigned structured proforma was used to collect information from hospital records of 18 medical centres across India. All participating centres were established primary care hospitals with adequate record keeping, a pre-determined condition in the study design. Data were collected during the period of January 2019 to June 2019. Data extracted from patient records, including glycaemic parameters, concomitant drugs, drug dosage and duration, were collated. The effectiveness of teneligliptin was assessed by analyzing the mean change in glycosylated haemoglobin (HbA1c), fasting plasma glucose (FPG) and post-prandial plasma glucose (PPG) at 12 weeks after initiation of teneligliptin.

RESULTS

Data from 10,623 patients were available for analysis. The mean age of the enrolled patients was 51.86 ± 11.76 years. At 12 weeks after initiation of teneligliptin as monotherapy or add-on to other medications (combination therapy), the patients showed a signficant decrease from baseline in mean HbA1c, FPG and PPG. Mean HbA1c dropped from 8.66 ± 1.15% at baseline to 7.67 ± 1.28% at 12 weeks (71 ± 12.6 to 60 ± 14 mmol/mol), with a difference of - 0.99% (95% confidence interval [CI] 0.96-1.02) or - 10.8 (95% CI 10.5-11.1) mmol/mol (p < 0.0001). The mean reductions in FPG and PPG were 43.12 mg/dL (2.39 mmol/L) and 87.73 mg/dL (4.87 mmol/L) (both p < 0.0001) respectively. HbA1c (%) reductions with teneligliptin when used as add-on to metformin, add-on to metformin + sulfonylurea combination and add-on to metformin + sulfonylurea + alpha glucosidase inhibitor combination were 0.76% (8.3 mmol/mol), 1.24% (13.6 mmol/mol) and 1.04% (11.4 mmol/mol), respectively. Teneligliptin also significantly reduced HbA1c (1.13% or 12.4 mmol/mol, p < 0.0001) in patients with impaired renal function, without worsening the estimated glomerular filtration rate. Teneligliptin consistently reduced HbA1c across all three age categories tested-by 1% (10.9 mmol/mol) in patients aged < 60 years, by 1.15% (12.6 mmol/mol) in patients aged 60-75 years and by 0.88% (9.6 mmol/mol) in patients aged > 75 years.

CONCLUSION

Teneligliptin significantly improved glycaemic parameters in Indian patients with T2DM when prescribed either as monotherapy or as an add-on to one or more other commonly prescribed antihyperglycaemic agents.

DPP-4 Inhibitors: Renoprotective Potential and Pharmacokinetics in Type 2 Diabetes Mellitus Patients with Renal Impairment

The continuously increasing incidence of diabetes worldwide has attracted the attention of the scientific community and driven the development of a novel class of antidiabetic drugs that can be safely and effectively used in diabetic patients. Of particular interest in this context are complications associated with diabetes, such as renal impairment, which is the main cause of high cardiovascular morbidity and mortality in diabetic patients. Intensive control of glucose levels and other risk factors associated with diabetes and metabolic syndrome provides the foundations for both preventing and treating diabetic nephropathy. Dipeptidyl peptidase-4 (DPP-4) inhibitors represent a highly promising novel class of oral agents used in the treatment of type 2 diabetes mellitus that may be successfully combined with currently available antidiabetic therapeutics in order to achieve blood glucose goals. Beyond glycemic control, emerging evidence suggests that DPP-4 inhibitors may have desirable off-target effects, including renoprotection. All type 2 diabetes mellitus patients with impaired renal function require dose adjustment of any DPP-4 inhibitor administered except for linagliptin, for which renal excretion is a minor elimination pathway. Thus, linagliptin is the drug most frequently chosen to treat type 2 diabetes mellitus patients with renal failure.

DPP-4 inhibitor reduces striatal microglial deramification after sensorimotor cortex injury induced by external force impact

Dipeptidyl peptidase-4 inhibitors (or gliptins), a class of antidiabetic drugs, have recently been shown to have protective actions in the central nervous system. Their cellular and molecular mechanisms responsible for these effects are largely unknown. In the present study, two structurally different gliptins, sitagliptin and vildagliptin, were examined for their therapeutic actions in a controlled cortical impact (CCI) model of moderate traumatic brain injury (TBI) in mice. Early post-CCI treatment with sitagliptin, but not vildagliptin, significantly reduced body asymmetry, locomotor hyperactivity, and brain lesion volume. Sitagliptin attenuated post-CCI microglial deramification in the ipsilateral dorsolateral (DL) striatum, while vildagliptin had no effect. Sitagliptin also reduced striatal expression of galectin-3 and monocyte chemoattractant protein 1(MCP-1), and increased the cortical and striatal levels of the anti-inflammatory cytokine IL-10 on the ipsilateral side. These data support a differential protective effect of sitagliptin against TBI, possibly mediated by an anti-inflammatory effect in striatum to preserve connective network. Both sitagliptin and vildagliptin produced similar increases of active glucagon-like peptide-1 (GLP-1) in blood and brain. Increasing active GLP-1 may not be the sole molecular mechanisms for the neurotherapeutic effect of sitagliptin in TBI.

Synthesis and discovery of triazolo-pyridazine-6-yl-substituted piperazines as effective anti-diabetic drugs; evaluated over dipeptidyl peptidase-4 inhibition mechanism and insulinotropic activities

A family of 12 triazolo-pyridazine-6-yl-substituted piperazines (5a-l) was synthesized and evaluated for their Dipeptidyl peptidase-4 (DPP-4) inhibition potentials in order to develop them as anti-diabetic medications. In the two-step synthesis process, 6-chloro-3-(m-tolyl)-[1,2,4]triazolo[4,3-b]pyridazine was synthesized with one-pot mode using pyridine, 3,6-dichloropyridazine 5-(3-methyl-phenyl)tetrazole in toluene. Conjugating corresponding 2° amines with 6-chloro-3-(m-tolyl)-[1,2,4]triazolo[4,3-b]pyridazine afforded the target triazolo-pyridazine-6-yl-substituted piperazines (5a-l). DPP-4 inhibition potential of these compounds was testified in silico and in nitro along with their insulinotropic activities in 832/13 INS-1 cells. H₂O₂ radical scavenging assay and MTT assay were conducted to assess the antioxidant and cytotoxicity of these compounds respectively. Molecular docking and ELISA based enzyme inhibition assay results revealed the strong inhibition potential of the target compounds. MTT assay results indicated a maximum dose of 2.5 nM (IC₅₀ 1.25 nM) could be used and above this level vital for the cells. Compounds 5a, 5c, 5g and 5i were found with excellent antioxidant and insulinotropic activity up to 99%.

DPP8 is a novel therapeutic target for multiple myeloma

Dipeptidyl peptidases (DPPs) are proteolytic enzymes that are ideal therapeutic targets in human diseases. Indeed, DPP4 inhibitors are widely used in clinical practice as anti-diabetic agents. In this paper, we show that DPP4 inhibitors also induced cell death in multiple human myeloma cells. Among five DPP4 inhibitors, only two of them, vildagliptin and saxagliptin, exhibited apparent cytotoxic effects on myeloma cell lines, without any difference in suppression of DPP4 activity. As these two DPP4 inhibitors are known to have off-target effects against DPP8/9, we employed the specific DPP8/9 inhibitor 1G244. 1G244 demonstrated anti-myeloma effects on several cell lines and CD138+ cells from patients as well as in murine xenograft model. Through siRNA silencing approach, we further confirmed that DPP8 but not DPP9 is a key molecule in inducing cell death induced by DPP8/9 inhibition. In fact, the expression of DPP8 in CD38+ cells from myeloma patients was higher than that of healthy volunteers. DPP8/9 inhibition induced apoptosis, as evidenced by activated form of PARP, caspases-3 and was suppressed by the pan-caspase inhibitor Z-VAD-FMK. Taken together, these results indicate that DPP8 is a novel therapeutic target for myeloma treatment.

The Effect of the Chronic Administration of DPP4-Inhibitors on Systemic Oxidative Stress in Rats with Diabetes Type 2

Type 2 diabetes (T2DM) is characterized by well-preserved insulin secretion; however, the surrounding tissue is insensitive to insulin, resulting in increased blood glucose level due to the inability of tissues to convert glucose into energy. As a result of chronic non-regulation of glucose levels and high daily fluctuations in the blood, the micro- and macrovascular complications occur in these patients. Complications develop through two main mechanisms: induction of oxidative stress and innate immunity. In this regard, the aim of this study was to examine the effect of four week administration of DPP4 inhibitors (saxagliptin, sitagliptin and vildagliptin) to the parameters of oxidative stress and antioxidant defense in the group of rats with diabetes type 2 (T2DM). Sixty Wistar albino rats were divided randomly into 5 groups: group I: control healthy group; group II: rats with diabetes type 2; group III: rats with diabetes type 2 treated with 0.6 mg/kg of sitagliptin; group IV: rats with diabetes type 2 treated with 0.45 mg/kg of saxagliptin, group V: rats with diabetes type 2 treated with 9 mg/kg vildagliptin. The rats from experimental groups were fed with a high-fat diet for 4 weeks and after 6–8 h of starvation received one dose of streptozotocin (STZ) intraperitoneally (25 mg/kg body weight) to induce T2DM. Animals with fasting glucose above 7 mmol / L and insulin over 6 mmol / L were included in the study as rats with T2DM. Upon completion of the experiments, the blood was collected from the anesthetized animals and used for sphectrophotometrical determination of parameters of oxidative stress, and antioxidative defense. T2DM induced significant increase in production of reacitve oxygen species (ROS) (superoxide anion radical and hydrogen peroxide), but additional four-week administration of gliptins induced decrease in ROS values. On the other hand, T2DM induced decrease of nitric oxide, superoxide dismutase, catalaze, and reduced gluthation and concomitant therapy with gliptins induced increase of these parametars, suggesting significant antioxidant potential of this group of drugs.

The Impact of a Large Bolus Dose of l-leucine and l-isoleucine on Enteroendocrine and Pancreatic Hormones, and Glycemia in Healthy, Inactive Adults

Background: The ingestion of whey protein and amino acids with carbohydrate (CHO) enhances the release of glucagon-like peptide-1 (GLP-1) and glucose-dependent-insulinotropic peptide (GIP) that promote insulin secretion. It is unknown if L-isoleucine (Ile) and L-leucine (Leu) have this same effect. The purpose of this study was to examine how Ile and Leu influence both GLP-1 and GIP, subsequent pancreatic hormones, and glycemia in healthy, inactive adults. Methods: Twelve adults (6F/6M; age 27.4 ± 2 years; BMI 26.3 ± 2 kg/m²; lean body mass 53.2 ± 5 kg; body fat 34.1 ± 3%) completed four conditions in a randomized, cross-over fashion. Treatments standardized (0.3 g/kg·LBM⁻¹) (1) Leu, (2) Ile, (3) Equal (1:1 g) of Leu + Ile, and (4) placebo (Pla, 3.5 g inert stevia) ingested 30 min prior to an oral glucose tolerance test (OGTT). Samples of plasma glucose, insulin, glucagon, GIP_Total, and GLP-1_Active were assessed. Results: A treatment (p = 0.01) effect comparing Ile vs. Leu (p = 0.02) in GIP_Total. Area under the curve showed an increase in GIP_Total from Ile compared to Leu and Pla (p = 0.03). No effect was found on GLP-1. The ingestion of Ile prior to CHO augmented GIP concentration greater than Leu or Pla. No correlation was found between GIP, insulin, and glucose between conditions. Conclusions: Ile impacts GIP concentration, which did not relate to either insulin or glucose concentrations. Neither Ile, nor Leu seem to have an effect on hyperglycemia ingested prior to a CHO drink.

DPP-4 inhibitor saxagliptin ameliorates oxygen deprivation/reoxygenation-induced brain endothelial injury

Cardiovascular diseases are the main cause of death and disability among diabetes patients. Atherosclerosis-associated stroke is one of the most severe complications in diabetes patients. DPP-4 inhibitors are a class of potent anti-glycemic agents used to treat diabetes. Recently, some DPP-4 inhibitors have been shown to have cardiovascular benefits. In this study, we reveal that saxagliptin, one of the most widely used DPP-4 inhibitors, exhibits vascular protective effects against oxygen and glucose depletion/reoxygenation (OGD/R) in human brain vascular endothelial cells. Our data show that DPP-4 is fairly expressed in brain endothelial cells and its expression is induced by OGD/R. The results of MTT assay show that inhibition of DPP-4 by saxagliptin ameliorates OGD/R-induced reduced cell viability, and LDH assay demonstrated that saxagliptin reduces cellular toxicity. Furthermore, we show that saxagliptin mitigates OGD/R-induced collapse of mitochondrial membrane potential (MMP). Saxagliptin also reduces oxidative stress-induced release of 4-HNE and the NAPDH oxidase catalytic subunit NOX-4. At the molecular level, saxagliptin suppresses OGD/R-induced expression of pro-inflammatory cytokines and production of vascular adhesion molecules including tumor necrosis factor-α (TNF-α), interleukin (IL)-6, monocyte chemoattractant protein 1 (MCP-1), vascular cellular adhesion molecule 1 (VCAM-1), and E-selectin. Mechanistically, saxagliptin inhibits activation of the NF-κB pathway by OGD/R via its inhibitory effect on nuclear p65 and NF-κB promoter activity. Collectively, our study explicitly demonstrates the cellular protective effect of saxagliptin against OGD/R-induced brain endothelial injury. Our findings extend our recognition of the protective roles of DPP-4 inhibitors in brain vascular cells.

Teneligliptin inhibits lipopolysaccharide-induced cytotoxicity and inflammation in dental pulp cells

Diabetes mellitus is one of the most common health threatening disorders. Patients with chronic diabetes are at high risk of contracting oral diseases, including dental pulp damage. In this study, we reviewed how Teneligliptin, a commonly used anti-diabetic agent, protected dental pulp cells from lipopolysaccharide (LPS)-induced cytotoxicity and improved their viability. The dental pulp cells treated with Teneligliptin were resistant to LPS-induced reactive oxygen species (ROS) and its byproduct 4-hydroxynonenal (4-HNE) generation. The Teneligliptin recovered LPS-induced a reduction of cellular glutathione and produced cytokine including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). Mechanistically, we found that Teneligliptin suppressed LPS- that caused an expression of the cell surface receptor toll like receptor 4 (TLR-4) and the activation of JNK kinase and activator protein 1 (AP1) as well as the nuclear factor-κB (NF-κB) signal pathways. Collectively, our study demonstrates that the molecular mechanism Teneligliptin is a protective anti-diabetic agent in dental pulp cells and it has the potential to treat diabetes-associated dental pulp diseases.

The DPP-4 inhibitor saxagliptin ameliorates ox-LDL-induced endothelial dysfunction by regulating AP-1 and NF-κB

Diabetes-associated cardiovascular complications are the leading cause of death for diabetic patients. Dipeptidyl peptidase 4 (DPP-4) inhibitor agents, known as gliptins, are a class of potent anti-glycemic agents developed to treat diabetes. Recently, gliptins have been shown to have independent cardiovascular benefits. In this study, we revealed the protective role of saxagliptin in vascular endothelial cells. Our data show that saxagliptin suppresses oxidized low-density lipoprotein cholesterol (ox-LDL)-induced expression of its receptor lectin-like ox-LDL receptor-1 (LOX-1). Saxagliptin treatment reduces ox-LDL-induced production of cytokines and vascular adhesion molecules including tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), vascular cell adhesion molecule 1 (VCAM-1), and intercellular cell adhesion molecule-1 (ICAM-1). The presence of saxagliptin suppressed ox-LDL-induced adhesion of monocytes to endothelial cells in co-culture adhesion experiments. Moreover, saxagliptin mitigated ox-LDL-induced production of reactive oxygen species and suppressed elevated expression of endothelial nicotinamide adenine dinucleotide phosphate oxidase subunit (NOX-4) induced by ox-LDL. Mechanistically, saxagliptin exerted inhibitory effects against ox-LDL-induced phosphorylation of JNK kinase, expression of the activator protein 1 (AP-1) subunits c-Jun/c-fos, and AP-1 promoter activity. Saxagliptin also suppressed nuclear factor κB (NF-κB) p65 accumulation and inhibited its promoter activity. Our data elaborate the molecular mechanism of saxagliptin-mediated endothelial protection and indicate that saxagliptin could have vascular benefits independent on its anti-glycemic function.

Vascular protection of DPP-4 inhibitors in retinal endothelial cells in in vitro culture

People with diabetes are at high risk of developing diabetes-related eye disease, termed as diabetic retinopathy, due damage being caused to the blood vessels in the retina. An efficient medical treatment to reduce diabetic retinopathy can improve the quality of life for diabetes patients. In our study, we show that linagliptin, a commercially available DPP-4 inhibitor, plays a protective role in retinal vascular endothelial cells. The presence of linagliptin protects retinal endothelial cells against TNF-α-induced cytotoxicity and enhances their viability. Linagliptin treatment suppresses TNF-α-induced production of reactive oxygen species and improves mitochondrial membrane potential. Moreover, linagliptin suppresses TNF-α-induced production of pro-inflammatory and pro-adhesive vascular cytokines including IL-6, IL-8, ICAM-1, and VCAM-1. The presence of linagliptin in cell media can reduce the number of THP-1 cells that adhere to retina endothelial cells. Mechanistically, linagliptin potently suppresses TNF-α-induced accumulation of NF-κB nuclear protein p65 and activation of NF-κB promoter. Our data indicate that linagliptin is an anti-inflammatory diabetic agent, with the potential to be applied as a treatment for diabetic retinopathy.

The neurovascular protective effect of alogliptin in murine MCAO model and brain endothelial cells

Endothelial damage and blood brain barrier disruption contribute to ischemic stroke and brain injury. Gliptins are a novel class of treatment agents for diabetes, and recent studies have linked the use of gliptins to neuroprotection. Alogliptin is a type of orally available gliptin that was approved for clinical use by the FDA in 2013. In this study, we investigated the neurovascular protective effects of alogliptin both in vivo and in vitro. In a murine middle cerebral artery occlusion (MCAO) stroke model, administration of alogliptin ameliorated cerebral infarction and disruption of brain vascular permeability, and restored expression of the endothelial tight junction proteins occludin and zona occludens 1 (ZO-1). In brain vascular endothelial cells exposed to oxygen and glucose deprivation/reperfusion (OGD/R), alogliptin prevented OGD/R-induced high permeability of the endothelial monolayer. Alogliptin treatment recovered the reduction in occludin and ZO-1 induced by OGD/R. Moreover, alogliptin treatment prevented OGD/R-induced induction of metalloproteinase (MMP)-2 and MMP-9, and restored expression of tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2. Collectively, our data indicate that alogliptin can improve neurovascular integrity and exerts neuroprotective effects.

Patterns of glycaemic control in patients with type 2 diabetes mellitus initiating second-line therapy after metformin monotherapy: Retrospective data for 10 256 individuals from the United Kingdom and Germany

AIM

To investigate determinants of change in glycated haemoglobin (HbA1c) in patients with type 2 diabetes mellitus (T2DM) at 6 months after initiating uninterrupted second-line glucose-lowering therapies.

MATERIALS AND METHODS

This cohort study utilized retrospective data from 10 256 patients with T2DM who initiated second-line glucose-lowering therapy (switch from or add-on to metformin) between 2011 and 2014 in Germany and the UK. Effects of pre-specified patient characteristics on 6-month HbA1c changes were assessed using analysis of covariance.

RESULTS

Patients had a mean (standard error [SE]) baseline HbA1c of 8.68% (0.02); 28.5% of patients discontinued metformin and switched to an alternative therapy and the remainder initiated add-on therapy. Mean (SE) unadjusted 6-month HbA1c change was -1.27% (0.02). When adjusted for baseline HbA1c, 6-month changes depended markedly on the magnitude of the baseline HbA1c (HbA1c <9%, -0.45% per unit increase in HbA1c; HbA1c ≥9%, -0.87% per unit increase in HbA1c). Adjusted mean 6-month HbA1c reductions showed slight treatment differences (range, 0.92-1.09%; P < .001). Greater reductions in HbA1c were associated with second-line treatment initiation within 6 months of T2DM diagnosis (1.36% vs 1.03% [P < .001]) and advanced age (≥70 years, 1.13%; <70 years, 1.02% [P < .001]).

CONCLUSIONS

Many patients with T2DM have very high HbA1c levels when initiating second-line therapy, indicating the need for earlier treatment intensification. Patient-specific factors merit consideration when making treatment decisions.

Efficacy and Safety of Teneligliptin in Indian Patients with Inadequately Controlled Type 2 Diabetes Mellitus: A Randomized, Double-blind Study

AIMS

This study evaluated the efficacy and safety of teneligliptin in patients with inadequately controlled type 2 diabetes mellitus (T2DM).

SETTINGS AND DESIGN

This was a randomized, doubleblind, placebocontrolled, parallelgroup, multicenter, Phase III study.

SUBJECTS AND METHODS

Patients with T2DM and inadequate glycemic control (glycosylated hemoglobin [HbA1c]: >7.0-≤8.5%) were enrolled. Patients were randomly assigned (ratio: 2:1) to receive teneligliptin 20 mg (Glenmark) or placebo. The primary efficacy variable was change from baseline in HbA1c at week 16. Additional analyses included the proportion of patients who achieved target of HbA1c ≤7.0%, changes in fasting plasma glucose (FPG), and postprandial glucose (PPG).

STATISTICAL ANALYSIS

Mean change in HbA1c was analyzed using an analysis of covariance model, least square (LS) means, 95% confidence intervals (CIs), and P values were calculated.

RESULTS

Overall, 237 patients were included. Patients of the teneligliptin group showed reduced HbA1c levels (LS mean difference = -0.304% for intent-to-treat [ITT]; -0.291% for per-protocol (PP) populations) after 16 weeks of treatment, and a statistically significant difference was observed between the ITT (LS mean difference = 0.555; 95% CI: 0.176-0.934; P = 0.0043) and PP populations (LS mean difference = 0.642; 95% CI: 0.233-1.052; P = 0.0023). Target HbA1c level was achieved by a greater proportion of teneligliptin group patients (ITT, 43.4%; PP, 43.6%) than placebo group patients (ITT, 27.3%; PP, 26.6%). Reduction in FPG levels was observed in ITT (LS mean difference: 8.829; 95% CI: -4.357-22.016; P = 0.1883) and PP populations (LS mean difference: 11.710 mg/dL; 95% CI: -2.893-26.312; P = 0.1154). Reduction in PPG levels was higher in teneligliptin group than placebo group in both ITT (LS mean difference = 25.849 mg/dL; 95% CI: 7.143-44.556; P = 0.0070) and PP populations (LS mean difference = 25.683 mg/dL; 95% CI: 5.830-45.536; P = 0.0115). Overall, 44 patients (18.6%) experienced at least one adverse event. Three or more hypoglycemic events were experienced by 2.5% patients of teneligliptin group and none in placebo group.

CONCLUSION

Treatment with once-daily teneligliptin led to statistically significant and clinically meaningful reductions in HbA1c and PPG, and was well tolerated in Indian patients with T2DM.

Cost-effectiveness analysis of different dipeptidyl-peptidase 4 inhibitor drugs for treatment of type 2 diabetes mellitus

INTRODUCTION

Type 2 diabetes mellitus (T2DM) has burdened health systems in the world to the value of 500 billion dollars/year. Dipeptidyl peptidase 4 inhibitors (DPP-4 Inhibitors) have been strongly associated with spending on the treatment of T2DM by the courts in Brazil. The aim of this study was to estimate the most cost-effective DPP-4 Inhibitor for T2DM treatment. A pharmacoeconomic study of cost-effectiveness was performed in a medium-sized municipality in Minas Gerais state, Brazil.

METHODS

The data are from legalization in municipal health in 2013. The effectiveness of DPP-4 Inhibitors was measured by the reduction in glycated hemoglobin (A1c). The direct medical costs of drug and adverse drug reactions were identified. With these data, a cost-effectiveness ratio (CER) and construction of the decision tree for sensitivity analysis were performed.

RESULTS

The representative of the most effective in reducing A1c gliptins was sitagliptin in combination with metformin, it was able to reduce A1c by 1.16% (1.09 to 1.22, CI 95%). The drug with the lowest cost was linagliptin, with a cost per patient/year of US$ 481.42. Sensitivity analysis performed by the decision tree shows that sitagliptin in association with metformin had the CER of US$ 1,506.75 per patient/year, to reduce A1c by 1%.

CONCLUSION

The most cost-effective DPP-4 Inhibitor was sitagliptin with metformin.

KLK5 induces shedding of DPP4 from circulatory Th17 cells in type 2 diabetes

OBJECTIVE

Increasing plasma levels and activity of dipeptidyl peptidase-4 (DPP4 or CD26) are associated with rapid progression of metabolic syndrome to overt type 2 diabetes mellitus (T2DM). While DPP4 inhibitors are increasingly used as anti-hyperglycemic agents, the reason for the increase in plasma DPP4 activity in T2DM patients remains elusive.

METHODS

We looked into the source of plasma DPP4 activity in a cohort of 135 treatment naive nonobese (BMI < 30) T2DM patients. A wide array of ex vivo, in vitro, and in silico methods were employed to study enzyme activity, gene expression, subcellular localization, protease identification, surface expression, and protein-protein interactions.

RESULTS

We show that circulating immune cells, particularly CD4+ T cells, served as an important source for the increase in plasma DPP4 activity in T2DM. Moreover, we found kallikrein-related peptidase 5 (KLK5) as the enzyme responsible for cleaving DPP4 from the cell surface by directly interacting with the extracellular loop. Expression and secretion of KLK5 is induced in CD4+ T cells of T2DM patients. In addition, KLK5 shed DPP4 from circulating CD4+ T helper (Th)17 cells and shed it into the plasma of T2DM patients. Similar cleavage and shedding activities were not seen in controls.

CONCLUSIONS

Our study provides mechanistic insights into the molecular interaction between KLK5 and DPP4 as well as CD4+ T cell derived KLK5 mediated enzymatic cleavage of DPP4 from cell surface. Thus, our study uncovers a hitherto unknown cellular source and mechanism behind enhanced plasma DPP4 activity in T2DM.

Linagliptin versus sitagliptin in patients with type 2 diabetes mellitus: a network meta-analysis of randomized clinical trials

Background

Diabetes is one of the most common chronic and costly diseases worldwide and type 2 diabetes is the most common type which accounts for about 90% of cases with diabetes. New medication-therapy regimens such as those containing linagliptin alone or in combination with other medications (within the category of DDP-4 inhibitors) must be evaluated in terms of efficacy and compared with other currently used drugs and then enter the medication list of the country. Hence, this study aimed to compare the clinical efficacy of the two drugs, i.e. linagliptin and sitagliptin, in patients with type 2 diabetes.

Methods

A systematic review was conducted to identify all clinical trials published by 2015 which compared the two drugs in patients with type 2 diabetes. Using keywords such as “linagliptin”, “type 2 diabetes mellitus”, “sitagliptin” and related combinations, we searched databases including Scopus, PubMed, and Web of Science. The quality of the selected studies was evaluated using the Jadad score. Considering primary and secondary outcomes extracted from the reviewed studies, a network meta-analysis was used to conduct a systematic comparison between the two studied drugs.

Results

This network meta-analysis included 32 studies (Linagliptin vs PLB: n = 8, Sitagliptin vs PLB: n = 13, Linagliptin + MET vs PLB + MET: n = 4, and Sitagliptin + MET vs PLB + MET: n = 7) and a total of 13,747 patients. The results showed no significant difference between linagliptin and sitagliptin in terms of key efficacy and safety outcomes such as HbA1c changes from baseline, body weight change from baseline, percentage of patients achieving HbA1c <7, and percentage of patients experiencing hypoglycemic events (p > 0.05). The results showed that the efficacy of the two drug regimens was the same.

Conclusions

Based on the results, there was no significant difference between the two drugs, i.e. linagliptin and sitagliptin, in terms of efficacy; in other words, the efficacy of the two drugs was the same. Therefore, the use of these two drugs depends on their availability and cost.

Graphical abstract

Graphical abstract of the network meta-analysis performed to evaluate the alternatives under the study.

Electronic supplementary material

The online version of this article (10.1186/s40199-017-0189-6) contains supplementary material, which is available to authorized users.

Renoprotective Effects of the Dipeptidyl Peptidase-4 Inhibitor Sitagliptin: A Review in Type 2 Diabetes

Diabetic nephropathy (DN) is now the single commonest cause of end-stage renal disease (ESRD) worldwide and one of the main causes of death in diabetic patients. It is also acknowledged as an independent risk factor for cardiovascular disease (CVD). Since sitagliptin was approved, many studies have been carried out revealing its ability to not only improve metabolic control but also ameliorate dysfunction in various diabetes-targeted organs, especially the kidney, due to putative underlying cytoprotective properties, namely, its antiapoptotic, antioxidant, anti-inflammatory, and antifibrotic properties. Despite overall recommendations, many patients spend a long time well outside the recommended glycaemic range and, therefore, have an increased risk for developing micro- and macrovascular complications. Currently, it is becoming clearer that type 2 diabetes mellitus (T2DM) management must envision not only the improvement in glycaemic control but also, and particularly, the prevention of pancreatic deterioration and the evolution of complications, such as DN. This review aims to provide an overview of the current knowledge in the field of renoprotective actions of sitagliptin, namely, improvement in diabetic dysmetabolism, hemodynamic factors, renal function, diabetic kidney lesions, and cytoprotective properties.

Computational Analysis of Gynura bicolor Bioactive Compounds as Dipeptidyl Peptidase-IV Inhibitor

The inhibition of dipeptidyl peptidase-IV (DPPIV) is a popular route for the treatment of type-2 diabetes. Commercially available gliptin-based drugs such as sitagliptin, anagliptin, linagliptin, saxagliptin, and alogliptin were specifically developed as DPPIV inhibitors for diabetic patients. The use of Gynura bicolor in treating diabetes had been reported in various in vitro experiments. However, an understanding of the inhibitory actions of G. bicolor bioactive compounds on DPPIV is still lacking and this may provide crucial information for the development of more potent and natural sources of DPPIV inhibitors. Evaluation of G. bicolor bioactive compounds for potent DPPIV inhibitors was computationally conducted using Lead IT and iGEMDOCK software, and the best free-binding energy scores for G. bicolor bioactive compounds were evaluated in comparison with the commercial DPPIV inhibitors, sitagliptin, anagliptin, linagliptin, saxagliptin, and alogliptin. Drug-likeness and absorption, distribution, metabolism, and excretion (ADME) analysis were also performed. Based on molecular docking analysis, four of the identified bioactive compounds in G. bicolor, 3-caffeoylquinic acid, 5-O-caffeoylquinic acid, 3,4-dicaffeoylquinic acid, and trans-5-p-coumaroylquinic acid, resulted in lower free-binding energy scores when compared with two of the commercially available gliptin inhibitors. The results revealed that bioactive compounds in G. bicolor are potential natural inhibitors of DPPIV.

Monitoring safety and use of old and new treatment options for type 2 diabetic patients: a two-year (2013-2016) analysis

OBJECTIVE

To compare patients' and physicians' perceptions regarding effectiveness and tolerability of non-insulin hypoglycemic drugs in a cohort of type 2 diabetic patients; to verify whether a possible tridimensional link between effectiveness, tolerability, and adherence affects long-term therapeutic outcomes.

METHODS

A two-year observational study was performed in 1389 Type 2 diabetic patients by involving general practitioner clinics and Diabetes Centers. A decimal scale and the Morisky questionnaire were used, respectively, to assess effectiveness and tolerability perceptions, and medication adherence.

RESULTS

Physicians perceived therapy as more efficacious compared to their patients: perceived effectiveness was steady for physicians during the study whereas patients' perception not significantly decreased (mean score from >8 to 7.84 ± 1.69). Physicians assigned higher tolerability scores compared to patients but only at the beginning of the study; interestingly, physicians' tolerability perception was poorer than patients' perception at last follow-up (mean score = 7.57 ± 1.40 vs. 7.88 ± 1.84). Favorable (score >7) patients' perceptions about treatment effectiveness and tolerability were associated with higher adherence. Patients showed medium adherence across the study.

CONCLUSIONS

A mutual relationship between clinical effectiveness, adverse drug reactions, and adherence has been established, significantly impacting the clinical management of diabetic patients. A careful monitoring of this link by clinicians appears therefore necessary.

Comparison of charges and resource use associated with saxagliptin and sitagliptin

OBJECTIVES

Saxagliptin and sitagliptin are two commonly used dipeptidyl peptidase-4 (DPP-4) inhibitors. Little is known about their comparative effectiveness in the real world, particularly their impact on cost and resources use. The objective of this study was to analyze charges and resource use associated with saxagliptin and sitagliptin to understand the impact of these DPP-4 inhibitor treatment options in a real-world setting.

METHODS

This was a retrospective, new-user study approved by the Institutional Review Board at the University of Toledo. Data were collected from a US insurance claims dataset (OptumInsight) for patients newly initiating treatment with saxagliptin or sitagliptin between January 1, 2010 and December 31, 2011. ICD-9 code 250 was used to identify patients with T2D. Overall and diabetes-related medical and pharmacy charges were observed. Inpatient hospitalizations were also compared. Propensity score matching was used to balance the cohorts of patients prescribed saxagliptin and sitagliptin. Appropriate univariate statistical tests were applied to the propensity-matched sample to examine differences in resource utilization outcomes. Statistical significance was evaluated at P < 0.05.

RESULT

After the propensity score matching, each cohort included 7711 patients. Saxagliptin treatment was associated with lower overall charges ($13,292 vs $14,032; P = 0.0023) and overall medical charges ($9,540 vs $10,296; P = 0.0024) during the 6-month follow-up period compared with sitagliptin treatment. No significant differences were observed in the overall pharmacy charges ($3,751 vs $3,753; P = 0.6937) and the diabetes-related charges ($5,141 vs $5,232; P = 0.2957). All-cause and diabetes-related inpatient hospitalization rates were significantly lower with saxagliptin treatment (p = 0.0001 and p = 0.0019, respectively). All-caused inpatient charges were also significantly lower with saxagliptin ($2,917.26 vs $3445.89; P < 0.0001).

CONCLUSION

Compared with patients initiating sitagliptin treatment, patients initiating saxagliptin treatment reported lower overall and medical charges and lower overall and diabetes-related hospitalization rates. These findings may aid payers in managing patients with T2D.

A review of glycemic efficacy of liraglutide once daily in achieving glycated hemoglobin targets compared with exenatide twice daily, or sitagliptin once daily in the treatment of type 2 diabetes

Incretin-based therapies such as glucagon-like peptide-1 (GLP-1) receptor agonists (RA) and dipeptidyl peptidase-4 (DPP-4) inhibitors have gained prominence in recent years for the treatment of type 2 diabetes (T2D). Such therapies offer the potential to stimulate endogenous insulin activity in proportion to circulating glucose levels; thereby, lowering the risk of hypoglycemic episodes. The synthetic GLP-1 RA exenatide, the human GLP-1 RA liraglutide, and the DPP-4 inhibitor sitagliptin are the first agents in their respective classes to be approved for the treatment of T2D and their efficacy and safety has been studied extensively in clinical trials. This article reviewed the efficacy of liraglutide once daily in achieving clinical guidelines-recommended glycated hemoglobin A1c levels in patients with T2D compared with exenatide twice daily, or sitagliptin once daily, based on published literature, with an aim to elucidate the preferred choice of incretin-related therapy in treating uncontrolled T2D.

Antidiabetic treatment with gliptins: focus on cardiovascular effects and outcomes

The traditional oral pharmacological therapy for type 2 diabetes mellitus (T2DM) has been based on the prescription of metformin, a biguanide, as first line antihyperglycemic agent world over. It has been demonstrated that after 3 years of treatment, approximately 50 % of diabetic patients could achieve acceptable glucose levels with monotherapy; but by 9 years this had declined to only 25 %. Therefore, the implementation of a combined pharmacological therapy acting via different pathways becomes necessary, and its combination with a compound of the sulfonylurea group was along decades the most frequently employed prescription in routine clinical practice. Meglitinides, glitazones and alpha-glucosidase inhibitors were subsequently developed, but the five mentioned groups of oral antihyperglycemic agents are associated with variable degrees of undesirable or even severe cardiovascular events. The gliptins—also called dipeptidyl peptidase 4 (DPP4) inhibitors—are an additional group of antidiabetic compounds with increasing clinical use. We review the status of the gliptins with emphasis on their capabilities to positively or negatively affect the cardiovascular system, and their potential involvement in major adverse cardiovascular events (MACE). Alogliptin, anagliptin, linagliptin, saxagliptin, sitagliptin, teneligliptin and vildagliptin are the compounds currently in clinical use. Regardless differences in chemical structure and metabolic pathways, gliptins as a group exert favorable changes in experimental models. These changes, as an almost general rule, include improved endothelial function, reduction of inflammatory markers, oxidative stress ischemia/reperfusion injury and atherogenesis. In addition, increased adiponectin levels and modest decreases in lipidemia and blood pressure were reported. In clinical settings, several trials—notably the longer one, employing sitagliptin, with a mean follow-up period of 3 years—did not show an increased risk for ischemic events. Anyway, it should be emphasized that the encouraging results from basic science were not yet translated into clinical evidence, probably due the multiple and pleiotropic enzymatic effects of DPP4 inhibition. Moreover, when employing saxagliptin, while the drug was not associated with an augmented risk for ischemic events, it should be pinpointed that the rate of hospitalization for heart failure was significantly increased. Gliptins as a group constitute a widely accepted therapy for the management of T2DM, usually as a second-line medication. Nonetheless, for the time being, a definite relationship between gliptins treatment and improved cardiovascular outcomes remains uncertain and needs yet to be proven.

Protein misfolding and aggregation in Alzheimer's disease and type 2 diabetes mellitus

In general, proteins can only execute their various biological functions when they are appropriately folded. Their amino acid sequence encodes the relevant information required for correct three-dimensional folding, with or without the assistance of chaperones. The challenge associated with understanding protein folding is currently one of the most important aspects of the biological sciences. Misfolded protein intermediates form large polymers of unwanted aggregates and are involved in the pathogenesis of many human diseases, including Alzheimer's disease (AD) and Type 2 diabetes mellitus (T2DM). AD is one of the most prevalent neurological disorders and has worldwide impact; whereas T2DM is considered a metabolic disease that detrementally influences numerous organs, afflicts some 8% of the adult population, and shares many risk factors with AD. Research data indicates that there is a widespread conformational change in the proteins involved in AD and T2DM that form β-sheet like motifs. Although conformation of these β-sheets is common to many functional proteins, the transition from α-helix to β-sheet is a typical characteristic of amyloid deposits. Any abnormality in this transition results in protein aggregation and generation of insoluble fibrils. The abnormal and toxic proteins can interact with other native proteins and consequently catalyze their transition into the toxic state. Both AD and T2DM are prevalent in the aged population. AD is characterized by the accumulation of amyloid-β (Aβ) in brain, while T2DM is characterized by the deposition of islet amyloid polypeptide (IAPP, also known as amylin) within beta-cells of the pancreas. T2DM increases pathological angiogenesis and immature vascularisation. This also leads to chronic cerebral hypoperfusion, which results in dysfunction and degeneration of neuroglial cells. With an abundance of common mechanisms underpinning both disorders, a significant question that can be posed is whether T2DM leads to AD in aged individuals and the associations between other protein misfolding diseases.

DPP-4 inhibitors: pharmacological differences and their clinical implications

INTRODUCTION

Recently, incretin-based therapy was introduced for the treatment of type 2 diabetes (T2D). In particular, dipeptidyl peptidase-4 inhibitors (DPP-4i) (sitagliptin, vildagliptin, saxagliptin, linagliptin and alogliptin) play an increasing role in the management of T2D.

AREAS COVERED

An extensive literature search was performed to analyze the pharmacological characteristics of DPP-4i and their clinical implications.

EXPERT OPINION

DPP-4i present significant pharmacokinetic differences. They also differ in chemical structure, in the interaction with distinct subsites of the enzyme and in different levels of selectivity and potency of enzyme inhibition. Moreover, disparities in the effects on glycated hemoglobin, glucagon-like peptide-1 and glucagon levels and on glucose variability have been observed. However, indirect comparisons indicate that all DPP-4i have a similar safety and efficacy profiles. DPP-4i are preferred in overweight/obese and elderly patients because of the advantages of minimal or no influence on weight gain and low risk of hypoglycemia. For the same reasons, DPP-4i can be safely combined with insulin. However, currently cardiovascular outcomes related to DPP-4i are widely debated and the available evidence is controversial. Today, long-term studies are still in progress and upcoming results will allow us to better define the strengths and limits of this therapeutic class.

Dipeptidyl peptidase-4 inhibitors and their effects on the cardiovascular system

It is well known that patients with type 2 diabetes mellitus (T2DM) are at increased risk of cardiovascular (CV) disease. Elevated plasma glucose levels that independently lead to increased cardiovascular risk, combined with associated co-morbidities such as obesity, hypertension, and dyslipidemia, further contribute to the development of CV complications. Dipeptidyl peptidase 4 inhibitors (DPP-4 inhibitors) are a relatively new class of drugs used for the treatment of diabetes and recently have been widely used in clinical practice. They exert their actions through degradation inhibition of endogenous glucagon-like peptides (GLP-1) and glucose-dependent insulinotropic peptides (GIP), with a resulting increase in glucose mediated insulin secretion and a suppression of glucagon secretion. Since GLP-1 is known to have an impact not only on plasma glucose levels but also to have cardiovascular protective effects there is increased speculation of whether DPP-4 inhibitors will have similar effects. Though many short-term studies have been encouraging, ongoing long-term clinical trials on humans are needed to provide further clarity to the complete safety profiles of these agents in terms of cardiovascular risk, and whether they may exert potential cardiovascular benefit. This review includes available data on the cardiovascular effects of DPP-4 inhibitors as well as their overall safety profile.

The dipeptidyl peptidase IV inhibitors vildagliptin and K-579 inhibit a phospholipase C: a case of promiscuous scaffolds in proteins

The long term side effects of any newly introduced drug is a subject of intense research, and often raging controversies. One such example is the dipeptidyl peptidase-IV (DPP4) inhibitor used for treating type 2 diabetes, which is inconclusively implicated in increased susceptibility to acute pancreatitis. Previously, based on a computational analysis of the spatial and electrostatic properties of active site residues, we have demonstrated that phosphoinositide-specific phospholipase C (PI-PLC) from Bacillus cereus is a prolyl peptidase using in vivo experiments. In the current work, we first report the inhibition of the native activity of PI-PLC by two DPP4 inhibitors - vildagliptin (LAF-237) and K-579. While vildagliptin inhibited PI-PLC at micromolar concentrations, K-579 was a potent inhibitor even at nanomolar concentrations. Subsequently, we queried a comprehensive, non-redundant set of 5000 human proteins (50% similarity cutoff) with known structures using serine protease (SPASE) motifs derived from trypsin and DPP4. A pancreatic lipase and a gastric lipase are among the proteins that are identified as proteins having promiscuous SPASE scaffolds that could interact with DPP4 inhibitors. The presence of such scaffolds in human lipases is expected since they share the same catalytic mechanism with PI-PLC. However our methodology also detects other proteins, often with a completely different enzymatic mechanism, that have significantly congruent domains with the SPASE motifs. The reported elevated levels of serum lipase, although contested, could be rationalized by inhibition of lipases reported here. In an effort to further our understanding of the spatial and electrostatic basis of DPP4 inhibitors, we have also done a comprehensive analysis of all 76 known DPP4 structures liganded to inhibitors till date. Also, the methodology presented here can be easily adopted for other drugs, and provide the first line of filtering in the identification of pathways that might be inadvertently affected due to promiscuous scaffolds in proteins.

The dipeptidyl peptidase IV inhibitors vildagliptin and K-579 inhibit a phospholipase C: a case of promiscuous scaffolds in proteins

The long term side effects of any newly introduced drug is a subject of intense research, and often raging controversies. One such example is the dipeptidyl peptidase-IV (DPP4) inhibitor used for treating type 2 diabetes, which is inconclusively implicated in increased susceptibility to acute pancreatitis. Previously, based on a computational analysis of the spatial and electrostatic properties of active site residues, we have demonstrated that phosphoinositide-specific phospholipase C (PI-PLC) from Bacillus cereus is a prolyl peptidase using in vivo experiments. In the current work, we first report the inhibition of the native activity of PI-PLC by two DPP4 inhibitors - vildagliptin (LAF-237) and K-579. While vildagliptin inhibited PI-PLC at micromolar concentrations, K-579 was a potent inhibitor even at nanomolar concentrations. Subsequently, we queried a comprehensive, non-redundant set of 5000 human proteins (50% similarity cutoff) with known structures using serine protease (SPASE) motifs derived from trypsin and DPP4. A pancreatic lipase and a gastric lipase are among the proteins that are identified as proteins having promiscuous SPASE scaffolds that could interact with DPP4 inhibitors. The presence of such scaffolds in human lipases is expected since they share the same catalytic mechanism with PI-PLC. However our methodology also detects other proteins, often with a completely different enzymatic mechanism, that have significantly congruent domains with the SPASE motifs. The reported elevated levels of serum lipase, although contested, could be rationalized by inhibition of lipases reported here. In an effort to further our understanding of the spatial and electrostatic basis of DPP4 inhibitors, we have also done a comprehensive analysis of all 76 known DPP4 structures liganded to inhibitors till date. Also, the methodology presented here can be easily adopted for other drugs, and provide the first line of filtering in the identification of pathways that might be inadvertently affected due to promiscuous scaffolds in proteins.

Dipeptidyl peptidase-4 inhibitors in type 2 diabetes therapy--focus on alogliptin

Type 2 diabetes mellitus is a complex and progressive disease that is showing an apparently unstoppable increase worldwide. Although there is general agreement on the first-line use of metformin in most patients with type 2 diabetes, the ideal drug sequence after metformin failure is an area of increasing uncertainty. New treatment strategies target pancreatic islet dysfunction, in particular gut-derived incretin hormones. Inhibition of the enzyme dipeptidyl peptidase-4 (DPP-4) slows degradation of endogenous glucagon-like peptide-1 (GLP-1) and thereby enhances and prolongs the action of the endogenous incretin hormones. The five available DPP-4 inhibitors, also known as 'gliptins' (sitagliptin, vildagliptin, saxagliptin, linagliptin, alogliptin), are small molecules used orally with similar overall clinical efficacy and safety profiles in patients with type 2 diabetes. The main differences between the five gliptins on the market include: potency, target selectivity, oral bioavailability, long or short half-life, high or low binding to plasma proteins, metabolism, presence of active or inactive metabolites, excretion routes, dosage adjustment for renal and liver insufficiency, and potential drug-drug interactions. On average, treatment with gliptins is expected to produce a mean glycated hemoglobin (HbA1c) decrease of 0.5%-0.8%, with about 40% of diabetic subjects at target for the HbA1c goal <7%. There are very few studies comparing DPP-4 inhibitors. Alogliptin as monotherapy or added to metformin, pioglitazone, glibenclamide, voglibose, or insulin therapy significantly improves glycemic control compared with placebo in adult or elderly patients with inadequately controlled type 2 diabetes. In the EXAMINE trial, alogliptin is being compared with placebo on cardiovascular outcomes in approximately 5,400 patients with type 2 diabetes. In clinical studies, DPP-4 inhibitors were generally safe and well tolerated. However, there are limited data on their tolerability, due to their relatively recent marketing approval. Alogliptin will be used most when avoidance of hypoglycemic events is paramount, such as in patients with congestive heart failure, renal failure, and liver disease, and in the elderly.

Linagliptin: farmacology, efficacy and safety in type 2 diabetes treatment

Type 2 diabetes mellitus (T2DM) has a high prevalence and incidence around the world. The complex pathophysiology mechanism is among the barriers for diabetes treatment. Type 2 diabetes patients have dysfunction in incretin hormones (as glucagon-like peptide-1 or GLP-1, and glucose-dependent insulinotropic polypeptide or GIP). By inhibiting the dipeptidyl peptidase-4 (DPP-4) enzyme, it is possible to slow the inactivation of GLP-1 and GIP, promoting blood glucose level reduction in a glucose-dependent manner. Linagliptin is a highly specific and potent inhibitor of DPP-4 that is currently indicated for the treatment of type 2 diabetes. Clinical studies with linagliptin demonstrated efficacy in reducing glycated hemoglobin (HbA1c) levels in type 2 diabetes patients, while maintaining a placebo-like safety and tolerability profile. Linagliptin has an interesting pharmacokinetic profile in terms of its predominantly non-renal elimination and the main implication of this characteristic is that no dose adjustment is necessary in patients with renal disease. Also, no dose adjustment is required in patients with hepatic insufficiency, as well in elderly or obese patients. This article will review the pharmacokinetic profile, efficacy data and safety aspects of linagliptin in type 2 diabetes patients.