Adding prandial GLP-1 receptor agonists to basal insulin: a promising option for type 2 diabetes therapy

Background: Diabetes mellitus is a serious and increasingly prevalent condition in Canada and around the world. Treatment strategies have become increasingly complex, with a widening array of pharmacological agents available for glycemic management in type 2 diabetes mellitus (T2DM). New therapies that act in concert with available basal insulins may represent alternatives to basal insulin intensification with prandial or pre-mixed insulin. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have recently shown promise as useful additions to basal insulin, with significant reductions in glycated hemoglobin and potentially beneficial effects on body weight. This review will focus on pivotal clinical trials to assess the potential benefits of adding prandial GLP-1 RAs to basal insulin in patients with T2DM.

Methods: Clinical studies combining prandial GLP-1 RAs and basal insulin (published between 2011 and July 2017) were identified and reviewed in PubMed, the Cochrane Central Register of Clinical Trials (Issue 6, June 2017), and clinicaltrials.gov.

Results: Most of the studies presented in this review show that the addition of a prandial GLP-1 RA to basal insulin results in equal or slightly superior efficacy compared to the addition of prandial insulin, together with weight loss and less hypoglycemia.

Conclusions: The results of the studies suggest that a prandial GLP-1 RA as an add-on to basal insulin may be a safe and effective treatment intensification option (vs basal-plus or basal-bolus insulin).     

Comparison of glycemic variability in Japanese patients with type 1 diabetes receiving insulin degludec versus insulin detemir using continuous glucose monitoring: a randomized,cross-over,pilot study

Objective: To use continuous glucose monitoring (CGM) to compare glycemic variability in patients with type 1 diabetes (T1D) treated with insulin degludec (IDeg) versus insulin detemir (IDet).

Methods: Ten patients with T1D were randomly assigned to receive once-daily IDeg, followed by twice-daily IDet, or vice versa. Glucose variability was evaluated by CGM after >4 weeks of the first insulin and again after crossover to the second insulin.

Results: The total daily insulin dose (U/kg/day) and the total daily basal insulin dose (U/kg/day) were significantly lower during treatment with IDeg than with IDet [median (interquartile range): 0.55 (0.54–0.73) vs. 0.64 (0.54–0.83); P = 0.028, 0.24 (0.19–0.36) vs. 0.30 (0.19–0.39); P = 0.027]. The 24-hour mean glucose levels were not significantly different. However, their standard deviation (SD) was significantly smaller during treatments with IDeg than those with IDet [59.5 (39.5–71.0) vs. 72.8 (61.8–92.8); P = 0.008]. Their mean fasting glucose levels and the mean postprandial peak levels after breakfast and after dinner were significantly lower with IDeg.

Conclusions: A CGM-based comparison demonstrated that once-daily IDeg showed fewer glycemic fluctuations than twice-daily IDet. IDeg appears to stabilize blood glucose levels better during both daytime and nighttime (particularly, before and after breakfast) with a lower insulin dosage.     

Interaction between the insulin receptor and Grb14: a dynamic study in living cells using BRET

Grb14 is a molecular adaptor that binds to the activated insulin receptor (IR) and negatively regulates insulin signaling. We have studied the dynamics of interaction of the IR with Grb14, in real time, in living HEK cells, using bioluminescence resonance energy transfer (BRET). Insulin rapidly and dose-dependently stimulated this interaction. Removing insulin from the incubation medium only resulted in a modest decrease in BRET signal, indicating that the interaction between the IR and Grb14 can remain long after insulin stimulus has disappeared. BRET saturation experiments indicated that insulin markedly increases the affinity between IR and Grb14, resulting in recruitment of the adaptor to the activated IR. In addition, using both BRET and co-immunoprecipitation experiments, we demonstrated that insulin induced the dimerization of Grb14, most likely as a result of simultaneous binding of two Grb14 molecules on the activated IR. We also investigated the relationships between IR, Grb14 and the protein tyrosine phosphatase PTP1B. We observed that insulin-induced BRET between the IR and PTP1B was markedly reduced by Grb14, suggesting that Grb14 regulated this interaction in living cells. Using site-specific antibodies against phosphorylated tyrosines of the insulin receptor, we showed that Grb14 protected the three tyrosines of the kinase loop from dephosphorylation by PTP1B, while favouring dephosphorylation of tyrosine 972. This resulted in decreased IRS-1 binding to the IR and decreased activation of the ERK pathway. Our work suggests that Grb14 may regulate signalling through the insulin receptor by controlling its tyrosine-dephosphorylation in a site-specific manner.     

Integration of efficacy, pharmacokinetic and safety assessment of interleukin-1 receptor antagonist in a preclinical model of arthritis

Pharmacokinetic properties and safety profile of a drug are likely influenced by the disease state of a patient. In this study, we investigated the influence of arthritic processes on pharmacokinetics and immunotoxicity of interleukin-1 receptor antagonist (Anakinra) in the rat adjuvant arthritis model. Anakinra dose-dependently suppressed joint inflammation and degradation as demonstrated by reduced clinical arthritis score, paw thickness, synovial infiltration and bone degradation. In addition, plasma levels of chemokines MCP-1 and GRO/KC were reduced. Pharmacokinetic behaviour of Anakinra was influenced by disease state of the rats as judged from a decrease in C(max) and an increase of the MRT as the disease progressed at a dose of 24 and 72 mg Anakinra/kg body weight. The pharmacokinetic parameters increased dose-dependently, but non-proportionally with increasing dose. Low level anti-Anakinra antibody formation was observed at prolonged exposure to the biologic. Safety parameters, including haematology, splenic lymphocyte subset analysis, ex vivo stimulation of spleen cells and histopathology of immune system organs were affected by the disease itself to such extent that no additional effects of Anakinra could be observed. In conclusion, we demonstrated that pharmacokinetic behaviour of Anakinra was influenced by the arthritis background of the rats resulting in decreased internal exposure.     

GLP-1受体激动剂治疗2型糖尿病合并肾损伤患者的疗效和安全性:一项Meta分析

目的:评价胰高血糖素样肽-1受体激动剂(GLP-1RAs)在2型糖尿病(T2DM)合并肾损伤患者中的疗效和安全性,为该类药物的临床应用提供循证参考。方法:检索Medline、Embase、Cochrane Library、中国知网(CNKI)和万方数据库,查找有关GLP-1RAs治疗T2DM合并肾损伤患者的随机对照试验(RCT)。按照纳入与排除标准筛选文献,进行方法学质量评价之后提取相关资料,应用RevMan 5.3统计软件进行Meta分析。结果:最终纳入7项RCT,共计1 755例T2DM合并肾损伤患者。疗效方面,GLP-1RAs与胰岛素类似物或二肽基肽酶4抑制剂降低糖化血红蛋白的效应相当,但优于安慰剂,且该疗效在中重度肾损伤患者中比终末期肾病患者更佳;与对照组相比降低体质量[MD=－1.75,95% CI=(－2.18,－1.32),P<0.01]和降压作用[收缩压:MD=－7.79,95% CI=(－10.83,－4.74),P<0.01;舒张压:MD=－2.92,95% CI=(－4.79,－1.05),P=0.002]均有显著性差异;但降低空腹血糖和调节脂质代谢方面未见统计学差异。安全性方面,GLP-1RAs组与对照组致低血糖和肾损伤事件的发生率[RR=1.28,95% CI=(0.56,2.96),P=0.560;RR=0.85,95% CI=(0.44,1.62),P=0.620]无统计学差异,然而GLP-1RAs组胃肠道不良反应的发生率显著高于对照组(P<0.01)。结论:对于T2DM合并肾损伤患者,GLP-1RAs具有确切的降糖、减重和降压作用,而在终末期肾病患者中疗效降低;用药期间不增加低血糖和肾损伤风险,但应注意预防胃肠道不良反应的发生。     

Cognition and depression: the effects of fluvoxamine,a sigma‐1 receptor agonist,reconsidered

Cognitive impairment is a primary feature of patients with major depressive disorder (MDD) and is characterised by stress‐induced neural atrophy. Via alpha‐adrenergic, anti‐cholinergic and anti‐histaminic activities, several antidepressants can cause significant counter‐therapeutic cognitive impairment. Evidence is emerging of the involvement of sigma‐1 receptor agonism in the mechanism of action of some antidepressants, notably fluvoxamine. Sigma‐1 receptors are abundant in areas affected by depression/stress‐induced cerebral atrophy and their ligands have a unique pharmacological profile; they may promote neurogenesis and initiate adaptive neural plasticity as a protection/reaction to stress. Fluvoxamine, as a potent sigma‐1 receptor agonist, has shown ameliorating effects in animal models of psychosis, depression, stress, anxiety, obsessive‐compulsive disorder (OCD) and aggression and has been shown to improve cognitive impairments. In humans, fluvoxamine may repair central nervous system (CNS) atrophy and restore cognitive function. The current review explores the mechanisms through which sigma‐1 receptors can modulate cognitive function and examines how antidepressant therapy with fluvoxamine may help improve cognitive outcomes in patients with depression. Copyright © 2010 John Wiley & Sons, Ltd.     

Efficacy and safety of teneligliptin add-on to insulin monotherapy in Japanese patients with type 2 diabetes mellitus: a 16-week,randomized, double-blind,placebo-controlled trial with an open-label period

Objective: To assess the efficacy and safety of teneligliptin as add-on to insulin monotherapy in patients with type 2 diabetes mellitus (T2DM).

Research design and methods: In a 16-week, double-blind period, 148 Japanese T2DM patients with inadequate glycemic control with insulin and diet/exercise therapies were randomized to placebo or teneligliptin 20 mg. In a subsequent 36-week, open-label period, all patients received teneligliptin once daily. The primary outcome measure was change in HbA1c at the end of the double-blind period.

Results: The difference between placebo and teneligliptin in change in HbA1c in the double-blind period (least squares mean ± SE) was ?0.80% ± 0.11%; teneligliptin was superior (ANCOVA, P < 0.001). The HbA1c-lowering effect of teneligliptin was maintained throughout the open-label period. The incidence of adverse events was 53.5% with placebo and 44.2% with teneligliptin in the double-blind period, 66.7% in the placebo/teneligliptin group in the open-label period, and 77.9% in the teneligliptin/teneligliptin group over both double-blind/open-label periods. The incidence of hypoglycemic symptoms was 11.1% in the placebo/teneligliptin group in the open-label period and 27.3% in the teneligliptin/teneligliptin group over both double-blind/open-label periods.

Conclusion: Teneligliptin was effective and well tolerated in Japanese T2DM patients with inadequate glycemic control.

Clinical trial registration: NCT02081599     

Efficacy and safety of alogliptin added to insulin in Japanese patients with type 2 diabetes: a randomized,double-blind, 12-week,placebo-controlled trial followed by an open-label,long-term extension phase

Objective: To evaluate the efficacy and safety of alogliptin added to insulin in Japanese patients with type 2 diabetes mellitus (T2DM) who are poorly controlled with insulin and diet or exercise.

Study design: This was a randomized, double-blind, 12-week comparative trial of alogliptin and insulin versus placebo and insulin in 179 patients with T2DM followed by a 40-week, open-label phase in 169 patients on alogliptin and insulin.

Primary outcome measure: Change in glycated hemoglobin (HbA1c) from baseline to the end of double-blind phase (week 12).

Results: The change in HbA1c (least squares means) from baseline to week 12 was ?0.96% for the alogliptin and insulin group and ?0.29% for the placebo and insulin group. The point estimate (95% confidence interval) intergroup difference was ?0.66% ([?0.824%, ?0.503%]). In the alogliptin and insulin group, HbA1c started to decrease from week 2 onward and peaked by week 12. The proportions of patients who achieved HbA1c < 8.0, < 7.0 and < 6.0% at week 12 were significantly higher in alogliptin and insulin group (73.0, 23.3 and 1.1%) than in placebo and insulin group (25.0, 5.7 and 0%). Incidences of adverse effects were comparable between groups, with no relevant increases in hypoglycemia or weight gain seen.

Conclusions: Alogliptin 25 mg/day was effective and well tolerated when added to insulin in Japanese patients with inadequately controlled T2DM.     

Progress in the discovery and development of small-molecule modulators of G-protein-coupled receptor 40 (GPR40/FFA1/FFAR1): an emerging target for type 2 diabetes

Background: The family of G-protein-coupled receptors (GPCRs) serves as the target for almost a third of currently marketed drugs and provides the predominant mechanism through which extracellular factors transmit signals to the cell. GPCRs have been proved to be good therapeutic targets for metabolic disorders. In recent years, a number of companies have been actively involved in the discovery of small-molecule modulators of the GPR40 (FFA1) receptor. However, to date, no critical, comprehensive review on small-molecule modulators of GPR40 (FFA1) has been published. Objective: To review the discovery and development of small-molecule GPR40 (FFA1) agonists/antagonists by different research groups and to classify them based on the key structural features. Method: Systematic search, analysis, and summary of the publication and patent literature for small-molecule modulators of the GPR40 (FFA1) receptor to June 2008. The patent information for this review is drawn from the Integrity Prous, Scifinder, Esp@cenet, and freepatentonline.com databases. Conclusion: The para-substituted phenyl propionic acid scaffold has emerged as a common structural motif found in many GPR40 (FFA1) agonists, and compounds having an aromatic ring and a group capable of releasing a cation have exhibited excellent GPR40 (FFA1) agonistic activity. Several small-molecule agonists of GPR40 (FFA1) have been discovered, which offer a great promise in the treatment of type 2 diabetes.     

Antidepressants activate the lysophosphatidic acid receptor LPA1 to induce insulin-like growth factor-I receptor transactivation,stimulation of ERK1/2 signaling and cell proliferation in CHO-K1 fibroblasts

Different lines of evidence indicate that the lysophosphatidic acid (LPA) receptor LPA₁ is involved in neurogenesis, synaptic plasticity and anxiety-related behavior, but little is known on whether this receptor can be targeted by neuropsychopharmacological agents. The present study investigated the effects of different antidepressants on LPA₁ signaling. We found that in Chinese hamster ovary (CHO)-K1 fibroblasts expressing endogenous LPA₁ tricyclic and tetracyclic antidepressants and fluoxetine induced the phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2) and CREB. This response was antagonized by either LPA₁ blockade with Ki16425 and AM966 or knocking down LPA₁ with siRNA. Antidepressants induced ERK1/2 phosphorylation in human embryonic kidney (HEK)-293 cells overexpressing LPA₁, but not in wild-type cells. In PathHunter™ assay measuring receptor-β-arrestin interaction, amitriptyline, mianserin and fluoxetine failed to induce activation of LPA₂ and LPA₃ stably expressed in CHO-K1 cells. ERK1/2 stimulation by antidepressants and LPA was suppressed by pertussis toxin and inhibition of Src, phosphatidylinositol-3 kinase and insulin-like growth factor-I receptor (IGF-IR) activities. Antidepressants and LPA induced tyrosine phosphorylation of IGF-IR and insulin receptor-substrate-1 through LPA₁ and Src. Prolonged exposure of CHO-K1 fibroblasts to either mianserin, mirtazapine or LPA enhanced cell proliferation as indicated by increased [³H]-thymidine incorporation and Ki-67 immunofluorescence. This effect was inhibited by blockade of LPA₁- and ERK1/2 activity. These data provide evidence that different antidepressants induce LPA₁ activation, leading to receptor tyrosine kinase transactivation, stimulation of ERK1/2 signaling and enhanced cell proliferation.     

胰高血糖素样肽-1受体激动剂和二肽基肽酶-4抑制剂联用二甲双胍治疗2型糖尿病的疗效与安全性对比的系统评价

目的：比较胰高血糖素样肽-1（GLP-1）受体激动剂和二肽基肽酶-4（DPP-4）抑制剂联用二甲双胍治疗2型糖尿病的疗效和安全性。方法：计算机检索Pubmed,Embase,Cochrane Library,CNKI,WanFang,VIP,CBM数据库,纳入GLP-1受体激动剂和DPP-4抑制剂联用二甲双胍比较治疗2型糖尿病的随机对照试验（RCT）,检索时间截止至2016年6月1日。由两位研究者根据纳入排除标准筛选文献、提取资料以及对文献质量进行评价,采用Rev-Man 5.3.5软件对数据进行分析。结果：共纳入14篇RCT。Meta分析结果显示：GLP-1受体激动剂+二甲双胍在降低糖化血红蛋白,降低空腹血糖,减轻体重,降低收缩压方面均优于DPP-4抑制剂+二甲双胍,差异具有统计学意义;在降低舒张压方面,2组并无差别;DPP-4抑制剂+二甲双胍组不良反应发生率更低,差异具有统计学意义;在低血糖方面,2组发生率相当,没有统计学差异。结论：GLP-1受体激动剂+二甲双胍在降低2型糖尿病患者的血糖,体质量控制以及降低收缩压方面优于DPP-4抑制剂+二甲双胍,但是不良反应发生率更高。     

D1-receptor drugs and cocaine-seeking behavior: investigation of receptor mediation and behavioral disruption in rats

Rationale. Dopamine D1-receptor antagonists and agonists both attenuate cocaine-seeking behavior (i.e., operant responding in the absence of cocaine reinforcement) elicited by a cocaine prime or cocaine-paired stimuli. It remains unclear whether these effects are D1-receptor mediated. Objectives. The present study tested whether a D1 antagonist (SCH-23390) would reverse the attenuating effects of a D1 agonist (SKF-81297) on cocaine-seeking behavior and whether behavioral disruption is involved in these effects. Methods. Rats trained to press a lever for cocaine reinforcement with light and tone cues paired with each infusion underwent daily extinction sessions during which responding had no scheduled consequences (i.e., neither cocaine nor the cocaine-paired stimulus complex was available). After responding diminished, the effects of the D1 antagonist on the dose–response functions of the D1 agonist for reinstatement of cocaine-seeking behavior by response-contingent cue presentations or cocaine priming were examined. A separate experiment assessed the effects of the agonist on the dose–response function of the antagonist for cue reinstatement. Stereotyped behavior and activity were also measured during each test session. Results. The attenuating effects of SKF-81297 on cocaine-seeking behavior during cocaine-primed reinstatement were reversed by co-administration of SCH-23390. However, no evidence for reversal of the attenuation during cue reinstatement was found even though agonist-induced stereotypy and antagonist-induced hypoactivity were reversed by co-administration of the two drugs during the same test session. Conclusions. The findings suggest that the attenuating effects of D1-receptor drugs on cocaine-seeking behavior during cocaine reinstatement are mediated by dopamine D1 receptors; however, it remains unclear whether the effects of these drugs on cocaine-seeking behavior during cue reinstatement are D1-receptor mediated. Nevertheless, it is evident that the attenuation of cocaine-seeking behavior by these drugs is not simply due to behavioral disruption.     

Pharmacokinetics and pharmacodynamics of ponesimod,a selective S1P1 receptor modulator,in the first-in-human study

Aims

This study investigated the tolerability, safety, pharmacokinetics and pharmacodynamics of ponesimod, a novel oral selective sphingosine-1-phosphate (S1P₁) receptor modulator in development for the treatment of auto-immune diseases.

Methods

This was a double-blind, placebo-controlled, ascending, single-dose study. Healthy male subjects received doses of 1–75 mg or placebo control.

Results

Ponesimod was well tolerated. Starting with a dose of 8 mg, transient asymptomatic reductions in heart rate were observed. Ponesimod pharmacokinetics were dose proportional. The median time to maximal concentration ranged from 2.0 to 4.0 h, and ponesimod was eliminated with a mean half-life varying between 21.7 and 33.4 h. Food had a minimal effect on ponesimod pharmacokinetics. Doses of ≥8 mg reduced total lymphocyte count in a dose-dependent manner. Lymphocyte counts returned to normal ranges within 96 h. A pharmacokinetic/pharmacodynamic model was developed that adequately described the observed effects of ponesimod on total lymphocyte counts.

Conclusions

Single doses of ponesimod up to and including 75 mg were well tolerated. The results of this ascending single-dose study indicate an immunomodulator potential for ponesimod and a pharmacokinetic/pharmacodynamic profile consistent with once-a-day dosing.     

In vitro and in vivo biological activities of SR140333, a novel potent non-peptide tachykinin NK1 receptor antagonist

(S)1- {;2-[3-(3,4-dichlorophenyl)-1-(3-isopropoxyphenylacetyl)piperidin-3-yl]ethyl };-4-phenyl-1-azoniabicyclo[2.2.2]octane chloride (SR140333) is a new non-peptide antagonist of tachykinin NK₁ receptors. SR140333 potently, selectively and competitively inhibited substance P binding to NK₁ receptors from various animal species, including humans. In vitro, it was a potent antagonist in functional assays for NK₁ receptors such as [Sar⁹,Met(O₂)¹¹]substance P-induced endothelium-dependent relaxation of rabbit pulmonary artery and contraction of guinea-pig ileum. Up to 1 μM, it had no effect in bioassays for NK₂ ([βAla⁸]neurokinin A-induced contraction of endothelium-deprived rabbit pulmonary artery) and NK₃ ([MePhe⁷]neurokinin B-induced contraction of rat portal vein) receptors. The antagonism exerted by SR140333 toward NK₁ receptors was apparently non-competitive, with pD'₂ values (antagonism potency evaluated by the negative logarithm of the molar concentration of antagonist that produces a 50% reduction of the maximal response to the agonist) between 9.65 and 10.16 in the different assays. SR140333 also blocked in vitro [Sar⁹,Met(O₂)¹¹]substance P-induced release of acetylcholine from rat striatum. In vivo, SR140333 exerted highly potent antagonism toward [Sar⁹,Met(O₂¹¹]substance P-induced hypotension in dogs (ED₅₀ = 3 μg/kg i.v., bronchoconstriction in guinea-pig (ED₅₀ = 42 μg/kg i.v.) and plasma extravasation in rats (ED₅₀ = 7 μg/kg i.v.). Finally, it also blocked the activation of rat thalamic neurons after nociceptive stimulation (ED = 0.2 μg/kg i.v.).     

Hypothalamic insulin and glucagon-like peptide-1 levels in an animal model of depression and their effect on corticotropin-releasing hormone promoter gene activity in a hypothalamic cell line

Background

In depression, excessive glucocorticoid action may cause maladaptive brain changes, including in the pathways controlling energy metabolism. Insulin and glucagon-like peptide-1 (GLP-1), besides regulation of glucose homeostasis, also possess neurotrophic properties. Current study was aimed at investigating the influence of prenatal stress (PS) on insulin, GLP-1 and their receptor (IR and GLP-1R) levels in the hypothalamus. GLP-1 and GLP-1R were assayed also in the hippocampus and frontal cortex – brain regions mainly affected in depression. The second objective was to determine the influence of exendin-4 and insulin on CRH promoter gene activity in in vitro conditions.