Effects of dipeptidyl peptidase 4 inhibition on the endothelial control of the vascular tone.

Dipeptidyl peptidase 4 (DPP4) is a serine protease known to cleave incretin hormones, which stimulate insulin secretion after food intake, a fact that supported the development of its inhibitors (DPP4i or gliptins) for the treatment of type 2 diabetes mellitus. In addition to their glucose-lowering effects, DPP4i show benefits for the cardiovascular system that could be related, at least in part, to their protective action on vascular endothelium. DPP4i have been associated with the reversal of endothelial dysfunction, an important predictor of cardiovascular events and a hallmark of diseases such as atherosclerosis, diabetes mellitus, hypertension, and heart failure. In animal models of these diseases, DPP4i increase nitric oxide bioavailability and limits oxidative stress, thereby improving the endothelium-dependent relaxation. Similar effects on flow-mediated dilation and attenuation of endothelial dysfunction have also been noted in human studies, suggesting a value for gliptins in the clinical scenario, despite the variability of the results regarding the DPP4i used, treatment duration, and presence of comorbidities. In this mini-review, we discuss the advances in our comprehension of the DPP4i effects on endothelial regulation of vascular tone. Understanding the role of DPP4 and its involvement in the signaling mechanisms leading to endothelial dysfunction will pave the way for a broader use of DPP4i in conditions that endothelial dysfunction is a pivotal pathophysiological player.

The effect of mogamulizumab on the aberrant T cell population in the peripheral blood - A monocentric retrospective analysis.

BACKGROUND AND OBJECTIVES: The effect of mogamulizumab in cutaneous T-cell lymphoma (CTCL) on T cells (TC) in the peripheral blood and its potential role to navigate treatment intervals are explored. METHODS: We investigated within a retrospective monocentric analysis the effect of mogamulizumab on the CD3+ TC and the aberrant T cell population (TCP), i.e., the CD4+ /CD7- and the CD4+ /CD26- TC, analyzed by flow cytometry. RESULTS: Thirteen patients with CTCL were included. After four cycles there was a mean reduction of 57% in CD3+ TC, 72% in the CD4+ /CD7- and 75% in the CD4+ /CD26- TCP compared to the individual baseline of each patient. The reduction in CD4+ /CD7+ and CD4+ /CD26+ TC was lower, averaging 54% and 41%. A significant decrease in aberrant TCP was already evident after the first administration. A median plateau of TCP already occurred during the IP. Progressive disease occurred in 5/13 patients without a clear correlation to aberrant TCP. CONCLUSIONS: Already after one dose of mogamulizumab, aberrant TCP and, to a lesser extent, normal TC decrease. We did not observe a clear correlation between TCP and the efficacy of mogamulizumab, but further studies with larger numbers of patients are needed.

Comparison of causal forest and regression-based approaches to evaluate treatment effect heterogeneity: an application for type 2 diabetes precision medicine.

OBJECTIVE: Precision medicine requires reliable identification of variation in patient-level outcomes with different available treatments, often termed treatment effect heterogeneity. We aimed to evaluate the comparative utility of individualized treatment selection strategies based on predicted individual-level treatment effects from a causal forest machine learning algorithm and a penalized regression model. METHODS: Cohort study characterizing individual-level glucose-lowering response (6 month reduction in HbA1c) in people with type 2 diabetes initiating SGLT2-inhibitor or DPP4-inhibitor therapy. Model development set comprised 1,428 participants in the CANTATA-D and CANTATA-D2 randomised clinical trials of SGLT2-inhibitors versus DPP4-inhibitors. For external validation, calibration of observed versus predicted differences in HbA1c in patient strata defined by size of predicted HbA1c benefit was evaluated in 18,741 patients in UK primary care (Clinical Practice Research Datalink). RESULTS: Heterogeneity in treatment effects was detected in clinical trial participants with both approaches (proportion predicted to have a benefit on SGLT2-inhibitor therapy over DPP4-inhibitor therapy: causal forest: 98.6%; penalized regression: 81.7%). In validation, calibration was good with penalized regression but sub-optimal with causal forest. A strata with an HbA1c benefit > 10 mmol/mol with SGLT2-inhibitors (3.7% of patients, observed benefit 11.0 mmol/mol [95%CI 8.0-14.0]) was identified using penalized regression but not causal forest, and a much larger strata with an HbA1c benefit 5-10 mmol with SGLT2-inhibitors was identified with penalized regression (regression: 20.9% of patients, observed benefit 7.8 mmol/mol (95%CI 6.7-8.9); causal forest 11.6%, observed benefit 8.7 mmol/mol (95%CI 7.4-10.1). CONCLUSIONS: Consistent with recent results for outcome prediction with clinical data, when evaluating treatment effect heterogeneity researchers should not rely on causal forest or other similar machine learning algorithms alone, and must compare outputs with standard regression, which in this evaluation was superior.

Potential clinical implications of CD4+CD26high T cells for nivolumab treated melanoma patients.

BACKGROUND: Nivolumab is an anti-PD1 antibody that has dramatically improved metastatic melanoma patients' outcomes. Nevertheless, many patients are resistant to PD-1 inhibition, occasionally experiencing severe off-target immune toxicity. In addition, no robust and reproducible biomarkers have yet been validated to identify the correct selection of patients who will benefit from anti-PD-1 treatment avoiding unwanted side effects. However, the strength of CD26 expression on CD4+ T lymphocytes permits the characterization of three subtypes with variable degrees of responsiveness to tumors, suggesting that the presence of CD26-expressing T cells in patients might be a marker of responsiveness to PD-1-based therapies. METHODS: The frequency distribution of peripheral blood CD26-expressing cells was investigated employing multi-parametric flow cytometry in 69 metastatic melanoma patients along with clinical characteristics and blood count parameters at baseline (W0) and compared to 20 age- and sex-matched healthy controls. Percentages of baseline CD4+CD26high T cells were correlated with the outcome after nivolumab treatment. In addition, the frequency of CD4+CD26high T cells at W0 was compared with those obtained after 12 weeks (W1) of therapy in a sub-cohort of 33 patients. RESULTS: Circulating CD4+CD26high T cells were significantly reduced in melanoma patients compared to healthy subjects (p = 0.001). In addition, a significant association was observed between a low baseline percentage of CD4+CD26high T cells (< 7.3%) and clinical outcomes, measured as overall survival (p = 0.010) and progression-free survival (p = 0.014). Moreover, patients with clinical benefit from nivolumab therapy had significantly higher frequencies of circulating CD4+CD26high T cells than patients with non-clinical benefit (p = 0.004) at 12 months. Also, a higher pre-treatment proportion of circulating CD4+CD26high T cells was correlated with Disease Control Rate (p = 0.014) and best Overall Response Rate (p = 0.009) at 12 months. Interestingly, after 12 weeks (W1) of nivolumab treatment, percentages of CD4+CD26high T cells were significantly higher in comparison with the frequencies measured at W0 (p < 0.0001), aligning the cell counts with the ranges seen in the blood of healthy subjects. CONCLUSIONS: Our study firstly demonstrates that peripheral blood circulating CD4+CD26high T lymphocytes represent potential biomarkers whose perturbations are associated with reduced survival and worse clinical outcomes in melanoma patients.

Meta-analysis of factors associated with antidiabetic drug prescribing for type 2 diabetes mellitus.

BACKGROUND: There is a lack of consensus on prescribing alternatives to initial metformin therapy and intensification therapy for type 2 diabetes mellitus (T2DM) management. This review aimed to identify/quantify factors associated with prescribing of specific antidiabetic drug classes for T2DM. METHODS: Five databases (Medline/PubMed, Embase, Scopus, Web of Science) were searched using the synonyms of each concept (patients with T2DM, antidiabetic drugs and factors influencing prescribing) in both free text and Medical Subject Heading (MeSH) forms. Quantitative observational studies evaluating factors associated with antidiabetic prescribing of metformin, sulfonylurea, thiazolidinedione, Dipeptidyl-peptidase 4 inhibitors (DPP4-I), sodium glucose transporter 2 inhibitors (SGLT2-I), Glucagon-Like peptide receptor agonist (GLP1-RA) and insulin in outpatient settings and published from January 2009 to January 2021 were included. Quality assessment was performed using a Newcastle-Ottawa scale. The validation was done for 20% of identified studies. The pooled estimate was measured using a three-level random-effect meta-analysis model based on odds ratio [95% confidence interval]. Age, sex, body mass index (BMI), glycaemic control (HbA1c) and kidney-related problems were quantified. RESULTS: Of 2331 identified studies, 40 met the selection criteria. Of which, 36 and 31 studies included sex and age, respectively, while 20 studies examined baseline BMI, HbA1c and kidney-related problems. The majority of studies (77.5%, 31/40) were rated as good and despite that the overall heterogeneity for each studied factor was more than 75%, it is mostly related to within-study variance. Older age was significantly associated with higher sulfonylurea prescription (1.51 [1.29-1.76]), yet lower prescribing of metformin (0.70 [0.60-0.82]), SGLT2-I (0.57 [0.42-0.79]) and GLP1-RA (0.52 [0.40-0.69]); while higher baseline BMI showed opposite significant results (sulfonylurea: 0.76 [0.62-0.93], metformin: 1.22 [1.08-1.37], SGLT2-I: 1.88 [1.33-2.68], and GLP1-RA: 2.35 [1.54-3.59]). Both higher baseline HbA1c and having kidney-related problems were significantly associated with lower metformin prescription (0.74 [0.57-0.97], 0.39 [0.25-0.61]), but more insulin prescriptions (2.41 [1.87-3.10], 1.52 [1.10-2.10]). Also, DPP4-I prescriptions were higher for patients with kidney-related problems (1.37 [1.06-1.79]) yet lower among patients with higher HbA1c (0.82 [0.68-0.99]). Sex was significantly associated with GLP1-RA and thiazolidinedione prescribing (F:M; 1.38 [1.19-1.60] and 0.91 [0.84-0.98]). CONCLUSION: Several factors were identified as potential determinants of antidiabetic drug prescribing. The magnitude and significance of each factor differed by antidiabetic class. Patient's age and baseline BMI had the most significant association with the choice of four out of the seven studied antidiabetic drugs followed by the baseline HbA1c and kidney-related problems which had an impact on three studied antidiabetic drugs, whereas sex had the least impact on prescribing decision as it was associated with GLP1-RA and thiazolidinedione only.

Sodium glucose cotransporter-2-inhibitor dapagliflozin improves nonalcoholic fatty liver disease by ameliorating dipeptidyl-peptidase-4 protein expression in diabetic mice.

INTRODUCTION: Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease worldwide. It can progress from simple steatosis to nonalcoholic steatohepatitis and may even develop into liver fibrosis, hepatocirrhosis, or hepatocellular carcinoma, but there is no effective treatment. MATERIAL AND METHODS: Wild-type (wt) and diabetic (db/db) mouse NAFLD-induced models were used to investigate the hepatoprotective effects and potential mechanisms of dapagliflozin (a new oral hypoglycaemic drug) on type 2 diabetes mellitus (T2DM) complicated with NAFLD, and to establish wt and db/db mouse NAFLD-induced and dapagliflozin treatment models. RESULTS: Dapagliflozin reduces blood glucose, glycosylated haemoglobin, blood lipids, and serum transaminase levels in db/db mice and improves T2DM-related liver injury accompanied by NAFLD; the mechanism may be related to the decrease in dipeptidyl-peptidase-4 (DPP4) protein expression and improvement in liver enzymes. Further mechanism-related studies by our team revealed that dapagliflozin can also downregulate the expression of DPP4 proteins in the liver and reduce serum soluble DPP4 enzyme levels, thereby improving the hepatic steatosis and insulin resistance of NAFLD. CONCLUSION: Dapagliflozin may be an effective drug for the treatment of T2DM-induced NAFLD and NAFLD, providing a reliable laboratory basis and new treatment methods for the clinical treatment of NAFLD.

Lower risk of gout in sodium glucose cotransporter 2 (SGLT2) inhibitors versus dipeptidyl peptidase-4 (DPP4) inhibitors in type-2 diabetes.

OBJECTIVES: The effects of sodium-glucose cotransporter 2 inhibitors (SGLT2I) vs dipeptidyl peptidase-4 inhibitors (DPP4I) on the risk of new-onset gout remains unknown. This study aims to compare the effects of SGLT2I against DPP4I on gout risks. METHODS: This was a retrospective population-based cohort study of patients with type-2 diabetes mellitus treated with SGLT2I or DPP4I between 1 January 2015 and 31 December 2020 in Hong Kong. The study outcomes are new-onset gout and all-cause mortality. Propensity score matching (1:1 ratio) between SGLT2I and DPP4I was performed. Univariable and multivariable Cox regression models were conducted. Competing risks models and multiple approaches based on the propensity score were applied. RESULTS: This study included 43 201 patients [median age: 63.23 years old (Interquartile range, IQR): 55.21-71.95, 53.74% males; SGLT2I group: n = 16 144; DPP4I group: n = 27 057] with a median follow-up of 5.59 years (IQR: 5.27-5.81 years) since initial drug exposure. The incidence rate of developing gout [Incidence rate (IR): 2.5; 95% CI: 2.2, 2.9] among SGLT2I users was significantly lower than DPP4I users (IR: 5.2; 95% CI: 4.8, 5.8). SGLT2I was associated with 51% lower risks of gout (HR: 0.49; 95% CI: 0.42, 0.58; P-value < 0.0001) and 51% lower risks of all-cause mortality (HR: 0.49; 95% CI: 0.42, 0.58; P-value < 0.0001) after adjusting for significant demographics, past comorbidities, medications and laboratory results. The results remained consistent on competing risk and other propensity score approaches. CONCLUSIONS: SGLT2I use was associated with lower risks of new gout diagnosis compared with DPP4I use.

Gelsemine relieves the neuropathic pain by down-regulating DPP4 level in rats.

BACKGROUND: Based on the previous findings on the relieving role of gelsemine in neuropathic pain, this research aims to further investigate the relevant regulatory mechanism. METHODS: Targets of gelsemine were predicted using SwissTargetPrediction. The peripheral neuropathic pain rat model was established by ligating spinal nerves, and then gelsemine (10 µg for one day) or dipeptidyl peptidase 4 (DPP4) oligonucleotides (5 µg/day, for 7 days) was injected into intrathecal bolus of rats. The mechanical threshold (0, 1, 2, 4 h after the last injection) was examined to evaluate the mechanical allodynia of rats. After the mechanical threshold measurement, the rats were anesthetized with isoflurane and then sacrificed by cervical dislocation. IBA1- and DPP4-positive cells in the spinal dorsal horn of rats were determined using immunohistochemistry and immunofluorescence assays. The expressions of DPP4, IL-1ß and TNF-α in the spinal dorsal horn of rats were measured by Western blot and quantitative real-time PCR. RESULTS: DPP4 was one of the targets of gelsemine. Gelsemine could elevate the down-regulated mechanical threshold, and lessen the up-regulated IBA1- and DPP4-positive cells and expressions of DPP4, IL-1ß and TNF-α in the spinal dorsal horn of rats with neuropathic pain. DPP4 overexpression reversed the role of gelsemine in neuropathic pain. CONCLUSION: Gelsemine relieves neuropathic pain by down-regulating DPP4 level in rats, providing a novel drug candidate and biomarker for neuropathic pain treatment.

Role of DPP4 and DPP4i in Glucose Homeostasis and Cardiorenal Syndrome.

The objective of the review led to the pursuit of adopting dipeptidyl peptidase-4 inhibitors (DPP4i) as a novel pharmacotherapy in diabetes mellitus (DM) and cardiorenal syndrome (CRS). The CRS is defined as the co-existence of myocardial ischemia with renal failure. At present, the commercially available drugs enhance insulin secretion or action. However, most of the drugs are associated with adverse effects, such as weight gain or hypoglycemia. As a result, newer therapies with better safety and efficacy profiles are being explored. The DPP4 protease enzyme is involved in cardiovascular and renal diseases in association with over-expressed cytokines. The novel characteristic of DPP4i is to control the elevated blood glucose levels in response to nutrient ingestion without causing hypoglycemia. Also, DPP4i are indirectly involved in reducing myocardial ischemia by promoting cardioprotective peptides. They protect the glucagon-like peptide 1 (GLP-1) from the deteriorating effect of the DPP4 enzyme. The GLP-1 receptors (GLP-1R) are abundantly expressed in renal and cardiovascular tissue. The overexpression of GLP-1R will confer protection of the heart and kidney during CRS. DPP4i were found to significantly clear plasma glucose by the simultaneously activating natural thrombolytic system and increasing insulin levels. They can be used in the early stages of the disease, including pre-diabetes or obesity combined with impaired incretin response, while the combination of DPP4i with metformin or thiazolidinediones as insulin sensitizers offers an additional improvement in the treatment of DM. With its positive attributes in a host of associated parameters of interest, DPP4i are studied extensively in the present review.

Protective effects and mechanisms of Lizhong decoction against non-alcoholic fatty liver disease in a rat model.

OBJECTIVE: To investigate the protective effects and molecular mechanisms of Lizhong decoction (, LZD) against non-alcoholic fatty liver disease (NAFLD). METHODS: Male Wistar rats were fed a high-fat diet for four weeks to induce NAFLD, and were administered LZD by gavage for four weeks. Potential therapeutic targets for NAFLD were analyzed using network pharmacology. Liver pathology was evaluated using Oil Red O and hematoxylin-eosin staining. Furthermore, mitochondrial function, lipid metabolism, oxidative stress, and inflammatory response were examined. RESULTS: Rats with NAFLD exhibited high levels of hepatic damage and cholesterol deposition. Moreover, apoptosis was increased, superoxide dismutase and glutathione content were reduced, malondialdehyde content was increased, and the protein expression of inflammatory cytokines and p-c-Jun N-terminal kinase was increased. The LZD treatment ameliorated mitochondrial dysfunction, reduced liver damage, inhibited oxidative stress and inflammatory response, upregulated peroxisome proliferator-activated receptor (PPAR)-γ expression, and suppressed dipeptidyl peptidase 4 (DPP4) expression in the liver. CONCLUSION: It was found that LZD alleviates NAFLD by activating PPAR-γ and inhibiting DPP4.

Use of GLP-1 receptor agonists and subsequent risk of alcohol-related events. A nationwide register-based cohort and self-controlled case series study.

Animal studies have related glucagon-like peptide 1 receptor agonists (GLP-1) to lower alcohol intake. We examined whether GLP-1 was associated with risk of alcohol-related events in a nationwide cohort study and a self-controlled case series analysis including all new users of GLP1 (n = 38 454) and dipeptidyl peptidase 4 inhibitors (DPP4) (n = 49 222) in Denmark 2009-2017. They were followed for hospital contacts with alcohol use disorder or purchase of drugs for treatment of alcohol dependence in nationwide registers from 2009 to 2018. Associations were examined using Cox proportional hazard and conditional Poisson regression. During follow-up of median 4.1 years, 649 (0.7%) of participants were registered with an alcohol-related event. Initiation of GLP-1 treatment was associated with lower risk of an alcohol-related event (Hazard ratio = 0.46 (95%CI: 0.24-0.86) compared with initiation of DPP4 during the first 3 months of follow-up. Self-controlled analysis showed the highest risk of alcohol-related events in the 3-month pretreatment period (incidence rate ratio [IRR] = 1.25 (1.00-1.58)), whereas the risk was lowest in the first 3-month treatment period (IRR = 0.74 (0.56-0.97). In conclusion, compared with DPP4 users, individuals who start treatment with GLP-1 had lower incidence of alcohol-related events both in cohort and self-controlled analyses. Thus, there might be a transient preventive effect of GLP1 on alcohol-related events the first months after treatment initiation.

Oral glucagon-like peptide 1 analogue ameliorates glucose intolerance in db/db mice.

OBJECTIVES: We constructed a recombinant oral GLP-1 analogue in Lactococcus lactis (L. lactis) and evaluated its physiological functions. RESULTS: In silico docking suggested the alanine at position 8 substituted with serine (A8SGLP-1) reduced binding of DPP4, which translated to reduced cleavage by DPP4 with minimal changes in stability. This was further confirmed by an in vitro enzymatic assay which showed that A8SGLP-1 significantly increased half-life upon DPP4 treatment. In addition, recombinant L. lactis (LL-A8SGLP-1) demonstrated reduced fat mass with no changes in body weight, significant improvement of random glycemic control and reduced systemic inflammation compared with WT GLP-1 in db/db mice. CONCLUSION: LL-A8SGLP-1 adopted in live biotherapeutic products reduce blood glucose in db/db mice without affecting its function.

Serum autoantibody reactivity in bullous pemphigoid is associated with neuropsychiatric disorders and the use of antidiabetics and antipsychotics: a large, prospective cohort study.

BACKGROUND: Bullous pemphigoid (BP), the by far most frequent autoimmune blistering skin disease (AIBD), is immunopathologically characterized by autoantibodies against the two hemidesmosomal proteins BP180 (collagen type XVII) and BP230 (BPAG1 or dystonin). Several comorbidities and potentially disease-inducing medication have been described in BP, yet a systematic analysis of these clinically relevant findings and autoantibody reactivities has not been performed. OBJECTIVE: To determine associations of autoantibody reactivities with comorbidities and concomitant medication. METHODS: In this prospective multicenter study, 499 patients diagnosed with BP in 16 European referral centers were included. The relation between anti-BP180 NC16A and anti-BP230 IgG ELISA values at the time of diagnosis as well as comorbidities and concomitant medication collected by a standardized form were analysed. RESULTS: An association between higher serum anti-BP180 reactivity and neuropsychiatric but not atopic and metabolic disorders was observed as well as with the use of insulin or antipsychotics but not with dipeptidyl peptidase-4 (DPP4) inhibitors, inhibitors of platelet aggregation and L-thyroxine. The use of DPP4 inhibitors was associated with less anti-BP180 and anti-BP230 reactivity compared with BP patients without these drugs. This finding was even more pronounced when compared with diabetic BP patients without DPP4 inhibitors. Associations between anti-BP180 and anti-BP230 reactivities were also found in patients using insulin and antipsychotics, respectively, compared with patients without this medication, but not for the use of inhibitors of platelet aggregation, and L-thyroxine. CONCLUSION: Taken together, these data imply a relation between autoantibody reactivities at the time of diagnosis and both neuropsychiatric comorbidities as well as distinct concomitant medication suggesting a link between the pathological immune mechanisms and clinical conditions that precede the clinically overt AIBD.

Adipose-derived stromal cells reverse insulin resistance through inhibition of M1 expression in a type 2 diabetes mellitus mouse model.

BACKGROUND: Adipose tissue inflammation is considered as one of the major mechanisms underlying the pathogenesis of insulin resistance and complications in diabetes. Here, we aimed to study the effects of adipose-derived stromal cells on diabetes-induced insulin resistance and M1 cytokine expression. METHODS: Stromal vascular fractions (SVFs) purified from the inguinal adipose tissue of diabetic mice were treated with plasma from either nondiabetic (Lepr+/+) or diabetic (Leprdb/db) mice and injected into the inguinal white adipose tissue of Leprdb/db mice. RESULTS: We found that diabetic plasma treatment induced, whereas nondiabetic plasma suppressed TNF-α, IL-1ß, and dipeptidyl peptidase 4 (DPP4) mRNA expression in SVFs in vitro. Importantly, the injection of nondiabetic plasma-treated SVFs significantly decreased TNF-α, IL-6, IL-1ß, CCL2, and IL-33 and induced IL-10 mRNA expression in adipose tissue of Leprdb/db mice in vivo. Furthermore, we observed that nondiabetic plasma-treated SVFs increased mRNA expression of Foxp3 in adipose tissue macrophages and Foxp3 in adipose CD4+ T cells, decreased CD11b+CD11c+ cells in adipose tissue, and suppressed mRNA expression of ICAM-1, FCM3, IL-6, IL-1ß, iNOS, TNF-α, and DPP4 as well as protein expression of DPP4 and phosphorylated JNK and NF-κB in the liver of Leprdb/db mice. Moreover, we found that nondiabetic plasma-treated SVFs increased Akt activation following insulin administration and attenuated glucose intolerance in Leprdb/db mice. CONCLUSIONS: Our results demonstrate that nondiabetic plasma inhibits M1 but increases M2 cytokine expression in adipose tissue of diabetic mice. Most importantly, our findings reveal that nondiabetic plasma-treated SVFs are capable of mitigating diabetes-induced plasma DPP4 activity, liver inflammation, and insulin resistance and that may be mediated through suppressing M1 cytokines but increasing IL-10 and Tregs in adipose tissue. Altogether, our findings suggest that adipose stromal cell-based therapy could potentially be developed as an efficient therapeutic strategy for the treatment of diabetes.

Targeting Procalcitonin Protects Vascular Barrier Integrity.

Rationale: Capillary leakage frequently occurs during sepsis and after major surgery and is associated with microvascular dysfunction and adverse outcome. Procalcitonin is a well-established biomarker in inflammation without known impact on vascular integrity. Objectives: We determined how procalcitonin induces endothelial hyperpermeability and how targeting procalcitonin protects vascular barrier integrity. Methods: In a prospective observational clinical study, procalcitonin levels were assessed in 50 patients who underwent cardiac surgery and correlated to postoperative fluid and vasopressor requirements along with sublingual microvascular functionality. Effects of the procalcitonin signaling pathway on endothelial barrier and adherens junctional integrity were characterized in vitro and verified in mice. Inhibition of procalcitonin activation by dipeptidyl-peptidase 4 (DPP4) was evaluated in murine polymicrobial sepsis and clinically verified in cardiac surgery patients chronically taking the DPP4 inhibitor sitagliptin. Measurements and Main Results: Elevated postoperative procalcitonin levels identified patients with 2-fold increased fluid requirements (P < 0.01), 1.8-fold higher vasopressor demand (P < 0.05), and compromised microcirculation (reduction to 63.5 ± 2.8% of perfused vessels, P < 0.05). Procalcitonin induced 1.4-fold endothelial and 2.3-fold pulmonary capillary permeability (both Ps < 0.001) by destabilizing VE-cadherin. Procalcitonin effects were dependent on activation by DPP4, and targeting the procalcitonin receptor or DPP4 during sepsis-induced hyperprocalcitonemia reduced capillary leakage by 54 ± 10.1% and 60.4 ± 6.9% (both Ps < 0.01), respectively. Sitagliptin before cardiac surgery was associated with augmented microcirculation (74.1 ± 1.7% vs. 68.6 ± 1.9% perfused vessels in non-sitagliptin-medicated patients, P < 0.05) and with 2.3-fold decreased fluid (P < 0.05) and 1.8-fold reduced vasopressor demand postoperatively (P < 0.05). Conclusions: Targeting procalcitonin's action on the endothelium is a feasible means to preserve vascular integrity during systemic inflammation associated with hyperprocalcitonemia.

Re-adjudication of the Trial Evaluating Cardiovascular Outcomes with Sitagliptin (TECOS) with study-level meta-analysis of hospitalization for heart failure from cardiovascular outcomes trials with dipeptidyl peptidase-4 (DPP-4) inhibitors.

BACKGROUND: Trial Evaluating Cardiovascular Outcomes with Sitagliptin (TECOS) assessed the cardiovascular (CV) safety of sitagliptin versus placebo on CV outcomes in patients with type 2 diabetes and CV disease and found sitagliptin noninferior to placebo. Subsequently, based on feedback from FDA, the Sponsor of the trial, Merck & Co., Inc., engaged a separate academic research organization, the TIMI Study Group, to re-adjudicate a prespecified set of originally adjudicated events. METHODS: TIMI adjudicated in a blinded fashion all potential hospitalization for heart failure (HHF) events, all potential MACE+ events previously adjudicated as not an endpoint event, and a random subset (~10%) of MACE+ events previously adjudicated as an endpoint event. An updated study-level meta-analysis of four randomized, placebo-controlled, CV outcomes trials with dipeptidyl peptidase 4 (DPP-4) inhibitors was then performed. RESULTS: After re-adjudication of potential HHF events in the intent-to-treat population, there were 224 patients with a confirmed event in the sitagliptin arm (1.05/100 person-years) and 239 patients in the placebo arm (1.13/100 person-years), corresponding to a hazard ratio (HR) of 0.94 (95% confidence interval [95% CI]: 0.78-1.13, p = .49). Concordance between the outcome of the original adjudication and the re-adjudication for HHF events was 82.7%. The meta-analysis of CV outcomes trials with DPP-4 inhibitors with placebo and involving 43 522 patients yielded an HR of 1.07 (95% CI: 0.83-1.39), with moderate heterogeneity (p = .45, I2 = 62.07%). CONCLUSION: The results of this independent re-adjudication process and analyses of CV outcomes from TECOS were consistent with the original adjudication results and overall study findings. An updated study-level meta-analysis showed no overall significant risk for HHF with DPP-4 inhibitors, but with statistical heterogeneity.

Identification of peripheral blood CD26+ leukemic stem cells has a potential role in the rapid diagnosis of chronic myeloid leukemia.

BACKGROUND: Chronic myeloid leukemia (CML) is a hematopoietic stem cell (SC) neoplasm diagnosed by the demonstration of t(9;22)(BCR-ABL1) fusion gene. We performed a flow cytometric assay to identify CD26+ CML leukemic stem cells (LSCs) for its value as a standalone diagnostic investigation for CML and its utility for detection of residual disease in CML patients on therapy. METHODS: Patients with clinical suspicion of CML/CML on follow-up were included, and peripheral (PB) and/or bone marrow (BM) samples were utilized for flow cytometric analysis. PB and/or BM of patients with diseases other than CML were used as controls. A pre-titrated antibody cocktail containing CD45, CD34, CD38, and CD26 MoABs was used. RESULTS: A total of 104 samples (63 PB and 41 BM) from 64 patients [suspected CML (n = 30), CML on follow-up (n = 15), and non-CML (n = 19)] were tested. CD26+ LSCs were identified in all patients with a confirmed diagnosis of CML (median = 0.07 (range 0.002%-26.79%)). None of the patients in the control group (non-CML) and follow-up patients with negative reverse transcriptase-polymerase chain reaction (RT-PCR) results showed the presence of CD26+ LSCs. Also, there was a strong correlation between CD26+ CML LSCs in the PB and BM (r = .917). CONCLUSION: Flow cytometric identification of CD26+ LSCs in the peripheral blood can be a cheap, rapid, robust, and potential diagnostic tool for the diagnosis of CML compared to available testing methods. It is irrespective of BCR-ABL1 transcript type, and its role in residual disease monitoring needs thorough investigation.

Virtual screening and in vitro assays of novel hits as promising DPP-4 inhibitors.

Diabetes is a metabolic disorder that presents hyperglycemia and vascular complications due to the non-production of insulin or its inappropriate use by the body. One of the strategies to treat diabetes is the inhibition of dipeptidyl peptidase-4 (DPP-4) and it is interesting to conduct virtual screening studies to search for new inhibitors of the DPP-4 enzyme. This study involves a virtual screening using the crystallographic structure of DPP-4 and a compound subset from the ZINC database. To filter this compound subset, we used some physicochemical properties, positioning at the three DPP-4 binding sites, molecular interactions, and ADME-Tox properties. The conformations of ligands obtained from AutoDock Vina were analyzed using a consensus with other algorithms (AutoDock and GOLD). The compounds selected from virtual screening were submitted to biological assays using the "DPPIV-Glo™ protease assay". Cytotoxicity tests were also performed. One promising compound (ZINC1572309) established interactions with important residues at the binding site. The results of the ADME-Tox prediction for ZINC1572309 were compared with a reference drug (sitagliptin). The cytotoxicity of sitagliptin and ZINC1572309 were evaluated using the XTT short-term cytotoxic assay, including normal and tumor cell lines to observe the cellular response to inhibitor treatment at different genetic bases. Both compounds (ZINC1572309 and the reference drug - sitagliptin) also inhibited DPP-4 activity, suggesting interesting biological effects of the selected compound at non-cytotoxic concentrations. Therefore, from in silico and in vitro studies, a potential hit as DPP-4 inhibitor was discovered and it can be structurally optimized to achieve suitable activity and pharmacokinetic profiles.

TriMaster: randomised double-blind crossover study of a DPP4 inhibitor, SGLT2 inhibitor and thiazolidinedione as second-line or third-line therapy in patients with type 2 diabetes who have suboptimal glycaemic control on metformin treatment with or without a sulfonylurea-a MASTERMIND study protocol.

INTRODUCTION: Pharmaceutical treatment options for patients with type 2 diabetes mellitus (T2DM) have increased to include multiple classes of oral glucose-lowering agents but without accompanying guidance on which of these may most benefit individual patients. Clinicians lack information for treatment intensification after first-line metformin therapy. Stratifying patients by simple clinical characteristics may improve care by targeting treatment options to those in whom they are most effective. This academically designed and run three-way crossover trial aims to test a stratification approach using three standard oral glucose-lowering agents. METHODS AND ANALYSIS: TriMaster is a randomised, double-blind, crossover trial taking place at up to 25 clinical sites across England, Scotland and Wales. 520 patients with T2DM treated with either metformin alone, or metformin and a sulfonylurea who have glycated haemoglobin (HbA1c) >58 mmol/mol will be randomised to receive 16 weeks each of a dipeptidyl peptidase-4 inhibitor, sodium-glucose co-transporter-2 inhibitor and thiazolidinedione in random order. Participants will be assessed at the end of each treatment period, providing clinical and biochemical data, and their experience of side effects. Participant preference will be assessed on completion of all three treatments. The primary endpoint is HbA1c after 4 months of therapy (allowing a range of 12-18 weeks for analysis). Secondary endpoints include participant-reported preference between the three treatments, tolerability and prevalence of side effects. ETHICAL APPROVAL: This study was approved by National Health Service Health Research Authority Research Ethics Committee South Central-Oxford A, study 16/SC/0147. Written informed consent will be obtained from all participants. Results will be submitted to a peer-reviewed journal and presented at relevant scientific meetings. A lay summary of results will be made available to all participants. TRIAL REGISTRATION NUMBERS: 12039221; 2015-002790-38 and NCT02653209.

Phytochemicals in Garlic Extract Inhibit Therapeutic Enzyme DPP-4 and Induce Skeletal Muscle Cell Proliferation: A Possible Mechanism of Action to Benefit the Treatment of Diabetes Mellitus.

Diabetes mellitus is a severe health problem in Mexico, and its prevalence is increasing exponentially every year. Recently, DPP-4 (dipeptidyl peptidase-4) inhibitors have become attractive oral anti-hyperglycemic agents to reduce the pathology of diabetes. Gliptin's family, such as sitagliptin, vildagliptin, and alogliptin, are in clinical use to treat diabetes mellitus but possess side effects. Therefore, there is a specific need to look for new therapeutic scaffolds (biomolecules). Garlic bulb is widely used as a traditional remedy for the treatment of diabetes. The garlic extracts are scientifically proven to control glucose levels in patients with diabetes, despite the unknown mechanism of action. The aim of the study is to investigate the antidiabetic effects of ultrasonication assisted garlic bulb extract. To achieve this, in-vitro assays such as DPP-4 inhibitory and antioxidant activities were investigated. Further, functional group analysis using FTIR and identification of phytochemicals using mass spectrometry analysis was performed. The results showed that 70.9 µg/mL of garlic bulb extract inhibited 50% DPP-4 activity. On top of that, the garlic extract exhibited a 20% scavenging activity, equivalent to 10 µg/mL of ascorbic acid. Molecular docking simulations on identified phytochemicals using mass spectrometry revealed their potential binding at the DPP-4 druggable region, and therefore the possible DPP-4 inhibition mechanism. These results suggest that prepared garlic extract contains phytochemicals that inhibit DPP-4 and have antioxidant activity. Also, the prepared extract induces skeletal muscle cell proliferation that demonstrates the antidiabetic effect and its possible mechanism of action.