肠易激综合征模型大鼠血清胰高糖素样肽-1及结肠组织中其受体的变化

目的 观察肠易激综合征( IBS)不同亚型模型大鼠血清胰高糖素样肽(GLP)-1及结肠组织中GLP-1受体的变化,初步探讨GLP-1及其受体在IBS发病中的作用.方法 40只雄性SD大鼠均分为腹泻型IBS(D-IBS)模型组、灌肠对照组、便秘型IBS(C-IBS)模型组、灌胃对照组及空白对照组.乙酸加束缚应激法制备D-IBS模型,冰水灌胃法制备C-IBS模型.观察大鼠粪便变化,检测粪便重量、粪便含水量及大鼠小肠推进率,给予结直肠扩张(CRD)刺激,记录腹外斜肌放电活动(EMG),评价模型大鼠的内脏敏感性.酶联免疫法测定各组大鼠血清中活性GLP-1的含量.免疫组织化学法、实时定量PCR法及Western印迹法检测各组大鼠近端结肠及远端结肠组织中GLP-1 受体的分布和表达.结果 与各自的对照组及空白对照组相比,D-IBS模型组大鼠粪便湿重、粪便含水量及小肠推进率均上升(P＜0.05);C-IBS模型组粪便湿重、粪便含水量及小肠推进率均降低(P＜0.05).在压力为20、40及60 mm Hg(1 mm Hg=0.133 kPa)的结直肠扩张刺激下各模型组大鼠腹外斜肌放电幅值均较各对照组明显增加,且D-IBS模型组高于C-IBS模型组(P＜0.05).C-IBS模型组血清中活性GLP-1的水平高于D-IBS模型组(P＜0.05),IBS模型组和对照组之间差异无统计学意义.GLP-1受体主要分布在结肠黏膜组织、环肌层及肌间神经丛中.C-IBS模型组结肠组织中GLP-1受体mRNA及蛋白表达量显著高于灌胃对照组,D-IBS模型组结肠组织中表达量低于灌肠对照组(P＜0.05).结论 不同亚型IBS结肠组织中GLP-1受体的表达水平不同,血清GLP-1水平也不同,提示GLP-1及其受体的改变可能与IBS不同亚型的发生有关.     

The novel dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 (GLP-1) receptor agonist tirzepatide transiently delays gastric emptying similarly to selective long-acting GLP-1 receptor agonists

The effect of dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist (RA) tirzepatide on gastric emptying (GE) was compared to that of GLP-1RAs in non-clinical and clinical studies. GE was assessed following acute and chronic treatment with tirzepatide in diet-induced obese mice versus semaglutide or long-acting GIP analogue alone. Participants [with and without type 2 diabetes (T2DM)] from a phase 1, 4-week multiple dose study received tirzepatide, dulaglutide or placebo. GE was assessed by acetaminophen absorption. In mice, tirzepatide delayed GE to a similar degree to that achieved with semaglutide; however, these acute inhibitory effects were abolished after 2 weeks of treatment. GIP analogue alone had no effect on GE or on GLP-1's effect on GE. In participants with and without T2DM, once-weekly tirzepatide (≥5 and ≥4.5 mg, respectively) delayed GE after a single dose. This effect diminished after multiple doses of tirzepatide or dulaglutide in healthy participants. In participants with T2DM treated with an escalation schedule of tirzepatide 5/5/10/10 or 5/5/10/15 mg, a residual GE delay was still observed after multiple doses. These data suggest that tirzepatide's activity on GE is comparable to that of selective GLP-1RAs.     

Orforglipron (LY3502970), a novel,oral non-peptide glucagon-like peptide-1 receptor agonist: A Phase 1a,blinded, placebo-controlled,randomized, single- and multiple-ascending-dose study in healthy participants

Aim

To evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of single and multiple doses of orforglipron (LY3502970), an oral, non-peptide glucagon-like peptide-1 receptor agonist (GLP-1RA) in healthy participants.

Materials and Methods

This was a double-blind, placebo-controlled, Phase 1 study. Overtly healthy adults aged 18 to 65 years with body mass index of 20 to 40 kg/m² and glycated haemoglobin concentration of 47.5 mmol/mol (<6.5%) were eligible. In Part A, participants received single-dose orforglipron, with four cohorts receiving escalating doses (0.3-6 mg). In Part B, participants received 4 weeks of daily repeated oral orforglipron with doses escalating weekly to four different final target doses (2-24 mg).

Results

Ninety-two participants enrolled and received at least one study drug dose (32 in Part A [mean age 43.4 years] and 60 in Part B [mean age 42.5 years]). The most common adverse events were gastrointestinal tract-related. Pharmacokinetics were approximately dose proportional, and the mean t_1/2 was 24.6 to 35.3 hours after a single dose (0.3-6 mg). On Day 28, the mean t_1/2 was 48.1 to 67.5 hours across the dose range (2-24 mg). Substantial reductions in body weight of up to 5.4 kg were observed after 4 weeks in orforglipron-treated participants, compared to a reduction of 2.4 kg with placebo (P < 0.05). Orforglipron decreased fasting glucose levels across Days 1 to 28, and gastric emptying was delayed on Day 28.

Conclusions

Orforglipron's long half-life (25-68 hours) allows once-daily oral dosing, without water and food restrictions. Orforglipron had a pharmacodynamic and safety profile similar to that of injectable GLP-1RAs, which supports continued clinical development.     

Preventing all-cause hospitalizations in type 2 diabetes with sodium-glucose cotransporter-2 inhibitors and glucagon-like peptide-1 receptor agonists: A narrative review and proposed clinical approach

Patients with type 2 diabetes (T2D) are at increased risk for hospital admissions, and acute hospitalizations are associated with a worse prognosis. However, outcomes related to all-cause hospital admissions (ACHAs) were often overlooked in trials that demonstrated the cardiovascular and kidney benefits of sodium-glucose cotransporter-2 (SGLT2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1RAs). This review includes a contemporary literature summary of emerging data regarding the effects of SGLT2 inhibitors and GLP-1RAs on ACHAs. The role of SGLT2 inhibitors in preventing ACHAs was shown in exploratory investigations of several randomized controlled trials (RCTs) and was further supported by real-world evidence (RWE). However, the association between GLP-1RA use and lower ACHA risk was mainly shown through RWE, with minimal available RCT data. We also discuss the advantages and challenges of studying ACHAs. Finally, we propose an easily memorized (“ABCDE” acronym) clinical approach to evaluating T2D status and treatment in admitted patients, as they transition from hospital to community care. This systematic approach may assist clinicians in recognizing possible pitfalls in T2D management, thereby preventing subsequent hospitalizations and improving patient prognoses. While acute admission can sometimes be perceived as a management failure, it should also be viewed as an opportunity to take action to prevent the next hospitalization.     

Discovery and characterization of taspoglutide, a novel analogue of human glucagon-like peptide-1, engineered for sustained therapeutic activity in type 2 diabetes

Aim: Glucagon‐like peptide‐1 (GLP‐1) receptor agonists for the treatment of type 2 diabetes are administered by daily injection because of short plasma half‐lives, which result partly from the biochemical instability of these peptides. There is a medical need for GLP‐1 analogues that can be administered less frequently for patient convenience. Methods: We synthesized a series of human GLP‐1 (hGLP‐1(7‐36)NH₂) derivatives containing α‐aminoisobutyric acid (Aib) substitutions, analysed their enzymatic stabilities and evaluated their secondary structures using circular dichroism (CD) and nuclear magnetic resonance (NMR). Results: Plasma stability experiments showed that only the analogue containing Aib substitutions in both the N‐terminus (position 8) and the C‐terminus (position 35), [Aib^8,35]hGLP‐1(7‐36)NH₂ (BIM‐51077), was fully resistant to enzymatic cleavage. Incubation with human plasma kallikrein or plasmin confirmed that the Aib substitution at position 35 prevented protease cleavage around this residue, which contributes to the significantly enhanced plasma stability and increased plasma half‐life. CD revealed increased C‐terminal α‐helicity in Aib³⁵‐substituted analogues compared with both hGLP‐1(7‐36)NH₂ and analogues containing only Aib⁸ substitutions. Based on NMR studies, the secondary structure of BIM‐51077 is similar to hGLP‐1(7‐36)NH₂ with a slight increase in α‐helicity in the C‐terminus. Compared with hGLP‐1(7‐36)NH₂, BIM‐51077 had similar binding affinity for the human GLP‐1 receptor and activated this receptor with similar potency. Conclusions: We have discovered an Aib^8,35‐substituted analogue of native hGLP‐1(7‐36)NH₂ (BIM‐51077) that retains the structure of the native peptide, and has similar activity and enhanced stability. A sustained‐release formulation of this molecule (taspoglutide) is in phase‐3 clinical development.     

Glucagon-like peptide-1(9-36)amide metabolite inhibits weight gain and attenuates diabetes and hepatic steatosis in diet-induced obese mice

Aims: The metabolic syndrome, a disease arising from the world‐wide epidemic of obesity, is manifested as severe insulin resistance, hyperlipidaemia, hepatic steatosis and diabetes. Previously we reported that GLP‐1(9‐36)amide, derived from the gluco‐incretin hormone, glucagon‐like peptide‐1 (GLP‐1), suppresses gluconeogenesis in isolated hepatocytes. The aims of this study were to determine the effects of GLP‐1(9‐36)amide in diet‐induced obese mice that model the development of the metabolic syndrome. Methods: Mice rendered obese by feeding a very high fat diet were administered GLP‐1(9‐36)amide via subcutaneous osmopumps for 8 weeks. Body weight, energy intake, plasma insulin and glucose levels (insulin‐resistance), and hepatic steatosis were assessed. Results: Eight‐week infusions of GLP‐1(9‐36)amide inhibited weight gain, increased energy intake, prevented the development of fasting hyperinsulinaemia and hyperglycaemia, and curtailed the accumulation of liver triglycerides. The peptide had no effects in mice fed a normal chow diet. Notably, energy intake in the obese mice receiving GLP‐1(9‐36)amide was 20% greater than obese mice receiving vehicle control. Conclusions: GLP‐1(9‐36)amide exerts insulin‐like actions in the presence of insulin resistance and prevents the development of metabolic syndrome. Curtailment of weight gain in the face of increased caloric intake suggests that GLP‐1(9‐36)amide increases energy expenditure. These findings suggest the possibility of the use of GLP‐1(9‐36)amide, or a peptide mimetic derived there from, for the treatment of obesity, insulin resistance and the metabolic syndrome.     

An overview of once-weekly glucagon-like peptide-1 receptor agonists--available efficacy and safety data and perspectives for the future

Incretin-based therapies, such as the injectable glucagon-like peptide-1 (GLP-1) receptor agonists and orally administered dipeptidyl peptidase-4 (DPP-4) inhibitors, have recently been introduced into clinical practice. At present, the GLP-1 receptor agonists need to be administered once or twice daily. Several once-weekly GLP-1 receptor agonists are in phase 3 development. This review examines the efficacy, safety and perspective for the future of the once-weekly GLP-1 receptor agonists: exenatide once weekly, taspoglutide, albiglutide, LY2189265 and CJC-1134-PC, and compared them to the currently available agonists, exenatide BID and liraglutide QD. A greater reduction in haemoglobin A1c (HbA1c) and fasting plasma glucose was found with the once-weekly GLP-1 receptor agonists compared with exenatide BID, while the effect on postprandial hyperglycaemia was modest with the once-weekly GLP-1 receptor agonist. The reduction in HbA1c was in most studies greater compared to oral antidiabetic drugs and insulin glargine. The reduction in weight did not differ between the short- and long-acting agonists. The gastrointestinal side effects were less with the once-weekly agonists compared with exenatide BID, except for taspoglutide. Antibodies seem to be most frequent with exenatide once weekly, while hypersensitivity has been described in few patients treated with taspoglutide. Injection site reactions differ among the long-acting GLP-1 receptor agonists and are observed more frequently than with exenatide BID and liraglutide. In humans, no signal has been found indicating an association between the once-weekly agonists and C-cell cancer. The cardiovascular safety, durability of glucose control and effect on weight will emerge from several ongoing major long-term trials. The once-weekly GLP-1 receptor analogues are promising candidates for the treatment of type 2 diabetes, although their efficacy may not be superior to once-daily analogue liraglutide.     

Addition of glucagon-like peptide-1 receptor agonist therapy to insulin in C-peptide-positive patients with type 1 diabetes

We aimed to test the hypothesis that addition of glucagon-like peptide-1 receptor agonists (GLP-1RAs) to insulin in C-peptide-positive patients with type 1 diabetes (T1D) will result in a reduction in glycated haemoglobin (HbA1c) with reduced insulin requirements and a rise in C-peptide concentrations. We conducted a retrospective analysis of 11 normal-weight patients with T1D consecutively treated with a GLP-1RA in addition to insulin. Paired t tests were used to compare the changes in HbA1c, insulin doses, body weight, body mass index, and C-peptide concentrations prior to and 12 ± 1 weeks after GLP-1RA therapy. At the end of 12 ± 1 weeks of GLP-1RA therapy, HbA1c fell from 10.74 ± 0.96% (95 ± 10.5 mmol/mol) to 7.4 ± 0.58% (58 ± 6.3mmol/mol) (P < 0.01), body weight fell from 71 ± 2.0 to 69 ± 2 kg (P = 0.06), and total insulin dose was reduced by 64% from 33 ± 6 to 11 ± 5 units (P < 0.01). Five out of 10 patients did not require any insulin. C-peptide concentrations increased significantly from 0.43 ± 0.09 ng/ml (0.14 ± 0.02 nmol/L) to 1.42 ± 0.42ng/ml (0.47 ± 0.13 nmol/L) (P = 0.01). Addition of GLP-1RA therapy to insulin in normal-weight patients with T1D led to a reduction in HbA1c with reduced insulin requirements, a 3.5-fold increase in C-peptide concentrations and freedom from insulin therapy in 50% of patients who tolerated the GLP-1RA therapy over a period of 12 ± 1 weeks.