The mechanism by which imeglimin inhibits gluconeogenesis in rat liver cells

Imeglimin modulates mitochondria biology and facilitates mitokine secretion in 3T3-L1 adipocytes

AIMS

Imeglimin, a novel antidiabetic drug, has recently been reported to affect pancreatic β-cells and hepatocytes. Adipose tissue plays a crucial role in systemic metabolism. However, its effect on adipocytes remains unexplored. Herein, we investigated the effects of imeglimin on adipocytes, particularly in the mitochondria.

MAIN METHODS

The 3T3-L1 adipocytes were treated with imeglimin. Mitochondrial respiratory complex I activity and NAD+, NADH, and AMP levels were measured. Protein expression levels were determined by western blotting, mitochondrial DNA and mRNA expression levels were determined using quantitative polymerase chain reaction, and secreted adipocytokine and mitokine levels were determined using adipokine array and enzyme-linked immunosorbent assay.

KEY FINDINGS

Imeglimin inhibited complex I activity, decreased the NAD+/NADH ratio, and increased AMP levels, which were associated with the enhanced phosphorylation of AMP-activated protein kinase. In addition, imeglimin increased the mitochondrial DNA content and levels of mitochondrial transcription factor A and peroxisome proliferator-activated receptor-γ coactivator 1-α mRNA, which were abolished by Ly294002, a phosphoinositide 3-kinase inhibitor. Furthermore, imeglimin facilitated the expression levels of markers of the mitochondrial unfolded protein response, and the gene expression and secretion of two mitokines, fibroblast growth factor 21 and growth differentiation factor 15. The production of both mitokines was transcriptionally regulated and abolished by phosphoinositide 3-kinase and Akt inhibitors.

SIGNIFICANCE

Imeglimin modulates mitochondrial biology in adipocytes and may exert a mitohormetic effect through mitokine secretion.

Exploring new mechanisms of Imeglimin in diabetes treatment: Amelioration of mitochondrial dysfunction

With the increasing prevalence of type 2 diabetes mellitus (T2DM), it has become critical to identify effective treatment strategies. In recent years, the novel oral hypoglycaemic drug Imeglimin has attracted much attention in the field of diabetes treatment. The mechanisms of its therapeutic action are complex and are not yet fully understood by current research. Current evidence suggests that pancreatic β-cells, liver, and skeletal muscle are the main organs in which Imeglimin lowers blood glucose levels and that it acts mainly by targeting mitochondrial function, thereby inhibiting hepatic gluconeogenesis, enhancing insulin sensitivity, promoting pancreatic β-cell function, and regulating energy metabolism. There is growing evidence that the drug also has a potentially volatile role in the treatment of diabetic complications, including metabolic cardiomyopathy, diabetic vasculopathy, and diabetic neuroinflammation. According to available clinical studies, its efficacy and safety profile are more evident than other hypoglycaemic agents, and it has synergistic effects when combined with other antidiabetic drugs, and also has potential in the treatment of T2DM-related complications. This review aims to shed light on the latest research progress in the treatment of T2DM with Imeglimin, thereby providing clinicians and researchers with the latest insights into Imeglimin as a viable option for the treatment of T2DM.

Factors contributing to the clinical effectiveness of imeglimin monotherapy in Japanese patients with type 2 diabetes mellitus

AIMS/INTRODUCTION

To investigate the effect of patient characteristics on imeglimin effectiveness in Japanese patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

Data were pooled from two randomized, placebo-controlled, 24-week, double-blind studies of imeglimin monotherapy in Japanese adults with type 2 diabetes mellitus, with the proportion of responders (glycated hemoglobin [HbA1c] < 7.0%) and sustained responders (i.e., achieved and maintained response) in the imeglimin 1,000 mg twice daily group calculated at each visit. Patient factors significantly (P < 0.05) correlated with response were explored through multivariate logistic regression. Subgroup analyses compared the efficacy of imeglimin in patients with a HbA1c improvement less than or equal to -0.3% (early responders) versus greater than -0.3% (early non-responders) at week 4.

RESULTS

A total of 38.0% of imeglimin-treated patients and 7.2% of placebo-treated patients were responders (P < 0.001, number needed to treat = 4). The proportion of sustained responders at weeks 4, 8, 12, 16 and 20 was 10.6, 19.0, 24.0, 25.7 and 29.1%, respectively (>70% of responders at each visit). Improvements in HbA1c and fasting glucose were significantly greater in early responders versus early non-responders from week 4; between-group differences remained significant to week 24. Older age (odds ratio 1.09, 95% confidence interval 1.04-1.14; P < 0.001); treatment-naïve status vs previous treatment (odds ratio 3.70, 95% confidence interval 1.55-8.82; P = 0.003), and lower baseline HbA1c (odds ratio 0.06, 95% confidence interval 0.02-0.16; P < 0.001) predicted response.

CONCLUSIONS

A significantly higher proportion of patients receiving imeglimin 1,000 mg twice daily monotherapy were responders versus placebo. Most (>70%) were sustained responders, suggesting that response is fairly predictable. Older age, treatment-naïve status and early treatment response significantly predicted imeglimin effectiveness.

Cancer biology in diabetes update: Focusing on antidiabetic drugs

The association of type 2 diabetes with certain cancer risk has been of great interest for years. However, the effect of diabetic medications on cancer development is not fully understood. Prospective clinical trials have not elucidated the long-term influence of hypoglycemic drugs on cancer incidence and the safety for cancer-bearing patients with diabetes, whereas numerous preclinical studies have shown that antidiabetic drugs could have an impact on carcinogenesis processes beyond the glycemic control effect. Because there is no evidence of the safety profile of antidiabetic agents on cancer biology, careful consideration would be required when prescribing any medicines to patients with diabetes and existing tumor. In this review, we discuss the potential influence of each diabetes therapy in cancer 'initiation', 'promotion' and 'progression'.

Mitochondrial Fission in Nickel Nanoparticle-Induced Reproductive Toxicity: An In Vitro GC-1 Cell Study

Reproductive disorders and declining fertility rates are significant public health concerns affecting birth rates and future populations. Male infertility, often due to spermatogenesis defects, may be linked to environmental pollutants like nickel nanoparticles (Ni NPs). Ni NPs are extensively utilized across different industries. Nevertheless, their potential adverse effects cannot be overlooked. Previous studies have linked the reproductive toxicity induced by Ni NPs with disturbances in mitochondrial function. Mitochondrial division/fusion dynamics are crucial to their proper function, yet little is known about how Ni NPs perturb these dynamics and whether such perturbation contributes to the impairment of the male reproductive system. Herein, we demonstrated that the exposure of Ni NPs to the mouse-derived spermatogonia cell line (GC-1 cells) triggered DRP1-mediated mitochondrial division and the enhanced impairment of mitochondria, consequently promoting mitochondria-dependent cell apoptosis. Notably, both the mitochondrial division inhibitor (Mdivi-1) and lentiviral-transfected cells with low expression of Dnm1l-DK in these cells could mitigate the toxic effects induced by Ni NPs, pointing to the potential role of mitochondrial dynamics in Ni NP-induced reproductive toxicity. Collectively, our work contributes to the understanding of the mechanisms by which Ni NPs can impact male reproductive function and identifies mitochondrial division as a potential target for intervention.

Protective effects of imeglimin on the development of atherosclerosis in ApoE KO mice treated with STZ

BACKGROUND

Imeglimin is a new anti-diabetic drug which promotes insulin secretion from pancreatic β-cells and reduces insulin resistance in insulin target tissues. However, there have been no reports examining the possible anti-atherosclerotic effects of imeglimin. In this study, we investigated the possible anti-atherosclerotic effects of imeglimin using atherosclerosis model ApoE KO mice treated with streptozotocin (STZ).

METHODS

ApoE KO mice were divided into three groups: the first group was a normoglycemic group without injecting STZ (non-DM group, n = 10). In the second group, mice were injected with STZ and treated with 0.5% carboxymethyl cellulose (CMC) (control group, n = 12). In the third group, mice were injected with STZ and treated with imeglimin (200 mg/kg, twice daily oral gavage, n = 12). We observed the mice in the three groups from 10 to 18 weeks of age. Plaque formation in aortic arch and expression levels of various vascular factors in abdominal aorta were evaluated for each group.

RESULTS

Imeglimin showed favorable effects on the development of plaque formation in the aortic arch in STZ-induced hyperglycemic ApoE KO mice which was independent of glycemic and lipid control. Migration and proliferation of vascular smooth muscle cells and infiltration of macrophage were observed in atherosclerotic lesions in STZ-induced hyperglycemic ApoE KO mice, however, which were markedly reduced by imeglimin treatment. In addition, imeglimin reduced oxidative stress, inflammation and inflammasome in hyperglycemic ApoE KO mice. Expression levels of macrophage makers were also significantly reduced by imeglimin treatment.

CONCLUSIONS

Imeglimin exerts favorable effects on the development of plaque formation and progression of atherosclerosis.

Imeglimin profoundly affects the circadian clock in mouse embryonic fibroblasts

OBJECTIVE

Imeglimin is a novel antidiabetic drug structurally related to metformin. Metformin has been shown to modulate the circadian clock in rat fibroblasts. Accordingly, in the present study, we aimed to determine whether imeglimin can impact the circadian oscillator in mouse embryonic fibroblasts (MEFs).

METHODS

MEFs carrying a Bmal1-Emerald luciferase (Bmal1-ELuc) reporter were exposed to imeglimin (0.1 or 1 mM), metformin (0.1 or 1 mM), a nicotinamide phosphoribosyltransferase inhibitor FK866, and/or vehicle. Subsequently, Bmal1-ELuc expression and clock gene mRNA expression levels were measured at 10-min intervals for 55 h and 4-h intervals for 32 h, respectively.

RESULTS

Imeglimin significantly prolonged the period (from 26.3 to 30.0 h at 0.1 mM) and dose-dependently increased the amplitude (9.6-fold at 1 mM) of the Bmal1-ELuc expression rhythm; however, metformin exhibited minimal effects on these parameters. Moreover, imeglimin notably impacted the rhythmic mRNA expression of clock genes (Bmal1, Per1, and Cry1). The concurrent addition of FK866 partly inhibited the effects of imeglimin on both Bmal1-ELuc expression and clock gene mRNA expression.

CONCLUSION

Collectively, these results reveal that imeglimin profoundly affects the circadian clock in MEFs. Further studies are needed to evaluate whether imeglimin treatment could exert similar effects in vivo.

Efficacy, safety and tolerability of imeglimin in patients with type 2 diabetes mellitus: A meta-analysis of randomized controlled trials

AIMS/INTRODUCTION

This meta-analysis aimed to evaluate the efficacy and safety/tolerability of imeglimin, a novel oral antihyperglycemic agent, administered as monotherapy and adjunctive therapy in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

Parallel-group randomized controlled trials comparing imeglimin with placebo in adults with type 2 diabetes mellitus were included. Risk ratios or weighted mean differences (WMD) and 95% confidence intervals (CIs) were calculated using random effects models. The primary outcome for efficacy was the change in glycated hemoglobin (HbA1c). Secondary outcomes included other efficacy-related outcomes, specific adverse events, and changes in body weight and lipid parameters.

RESULTS

Nine randomized controlled trials (n = 1,655) were included. When analyzed by dose, there was a significant difference in glycated hemoglobin (%) between imeglimin monotherapy and placebo at doses >1,000 mg twice daily (1,000 mg: studies N = 3, patients n = 517, WMD = -0.714, P < 0.001; 1,500 mg: N = 5, n = 448, WMD = -0.531, P = 0.020; 2,000 mg: N = 1, n = 149, WMD = -0.450, P = 0.005). Imeglimin adjunctive therapy significantly improved glycated hemoglobin over placebo at doses of 1,000 mg (N = 1, n = 214, WMD = -0.600, P < 0.001) and 1,500 mg (N = 2, n = 324, WMD = -0.576, P < 0.001). Subgroup analysis of the primary outcome showed that imeglimin was effective regardless of chronic kidney disease category, with studies carried out in Japan and in patients with lower body mass index showing a trend toward improved imeglimin efficacy. There were no significant differences between imeglimin and placebo in the risk of all-cause discontinuation and the proportion of patients who presented with at least one adverse event.

CONCLUSIONS

Imeglimin is efficacious, safe, and well tolerated as monotherapy and adjunctive therapy.

Potential Ketoacidosis Linked to Imeglimin and Metformin Co-administration in a Patient With Type 2 Diabetes

A 74-year-old woman with type 2 diabetes mellitus developed ketoacidosis within six days of adding metformin to imeglimin treatment. The patient was insulin-sensitive and showed preserved insulin secretion; therefore, insulin insufficiency alone was unlikely to contribute to the development of ketoacidosis. Both imeglimin and metformin partially inhibit complex I in the mitochondrial respiratory chain. Inhibition of mitochondrial respiration can lead to tricarboxylic acid (TCA) cycle suppression. Thus, the entry of acetyl-coenzyme A into TCA cycle is restricted, and it is eventually used in ketogenesis. Therefore, the combination of imeglimin and metformin might have precipitated the development of ketoacidosis.

Glucose-Lowering Effects of Imeglimin and Its Possible Beneficial Effects on Diabetic Complications

Mitochondrial dysfunction is a prominent pathological feature of type 2 diabetes, which contributes to β-cell mass reduction and insulin resistance. Imeglimin is a novel oral hypoglycemic agent with a unique mechanism of action targeting mitochondrial bioenergetics. Imeglimin reduces reactive oxygen species production, improves mitochondrial function and integrity, and also improves the structure and function of endoplasmic reticulum (ER), changes which enhance glucose-stimulated insulin secretion and inhibit the apoptosis of β-cells, leading to β-cell mass preservation. Further, imeglimin inhibits hepatic glucose production and ameliorates insulin sensitivity. Clinical trials into the effects of imeglimin monotherapy and combination therapy exhibited an excellent hypoglycemic efficacy and safety profile in type 2 diabetic patients. Mitochondrial impairment is closely associated with endothelial dysfunction, which is a very early event in atherosclerosis. Imeglimin improved endothelial dysfunction in patients with type 2 diabetes via both glycemic control-dependent and -independent mechanisms. In experimental animals, imeglimin improved cardiac and kidney function via an improvement in mitochondrial and ER function or/and an improvement in endothelial function. Furthermore, imeglimin reduced ischemia-induced brain damage. In addition to glucose-lowering effects, imeglimin can be a useful therapeutic option for diabetic complications in type 2 diabetic patients.

Stimulatory effect of imeglimin on incretin secretion

AIMS/INTRODUCTION

Imeglimin is a new antidiabetic drug structurally related to metformin. Despite this structural similarity, only imeglimin augments glucose-stimulated insulin secretion (GSIS), with the mechanism underlying this effect remaining unclear. Given that glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) also enhance GSIS, we examined whether these incretin hormones might contribute to the pharmacological actions of imeglimin.

MATERIALS AND METHODS

Blood glucose and plasma insulin, GIP, and GLP-1 concentrations were measured during an oral glucose tolerance test (OGTT) performed in C57BL/6JJcl (C57BL/6) or KK-Ay/TaJcl (KK-Ay) mice after administration of a single dose of imeglimin with or without the dipeptidyl peptidase-4 inhibitor sitagliptin or the GLP-1 receptor antagonist exendin-9. The effects of imeglimin, with or without GIP or GLP-1, on GSIS were examined in C57BL/6 mouse islets.

RESULTS

Imeglimin lowered blood glucose and increased plasma insulin levels during an OGTT in both C57BL/6 and KK-Ay mice, whereas it also increased the plasma levels of GIP and GLP-1 in KK-Ay mice and the GLP-1 levels in C57BL/6 mice. The combination of imeglimin and sitagliptin increased plasma insulin and GLP-1 levels during the OGTT in KK-Ay mice to a markedly greater extent than did either drug alone. Imeglimin enhanced GSIS in an additive manner with GLP-1, but not with GIP, in mouse islets. Exendin-9 had only a minor inhibitory effect on the glucose-lowering action of imeglimin during the OGTT in KK-Ay mice.

CONCLUSIONS

Our data suggest that the imeglimin-induced increase in plasma GLP-1 levels likely contributes at least in part to its stimulatory effect on insulin secretion.

Efficacy and safety of imeglimin in type 2 diabetes: A systematic review and meta-analysis of randomized placebo-controlled trials

BACKGROUND & AIMS

Imeglimin is a novel new oral compound recently approved for treating type 2 diabetes (T2D) in India. We conducted a systematic review and meta-analysis to evaluate the efficacy of imeglimin in people with T2D in the approved dose of 1000 mg twice daily (BID).

METHODS

We systematically searched the database of PubMed until December 20, 2022, and retrieved all published double-blind, randomized, placebo-controlled trials (RCTs) conducted with imeglimin 1000 mg BID, using appropriate keywords and MeSH terms. A meta-analysis was conducted to study the HbA1c lowering effect of imeglimin 1000 mg BID in people with T2D using the Comprehensive meta-analysis (CMA) software Version 3, Biostat Inc. Englewood, NJ, USA.

RESULTS

Of the seven Phase 2 studies and three Phase 3 studies conducted so far, only three published double-blind RCTs have reported the efficacy and safety of imeglimin 1000 mg BID against the placebo. Our meta-analysis using the random-effects model from two monotherapy studies (n = 360) showed imeglimin 1000 mg BID reduce HbA1c significantly (Δ -0.9%, 95% Confidence Interval [CI], -1.1 to -0.74%; P < 0.0001) against the placebo, without any heterogeneity (I² = 0%). The pooled meta-analysis from all three RCTs (n = 574) found a significant reduction in HbA1c with imeglimin 1000 mg BID (Δ -0.79%; 95% CI, -1.00 to -0.59%; P < 0.0001) compared to placebo with high heterogeneity.

CONCLUSIONS

This meta-analysis found a significant HbA1c lowering effect of imeglimin in people with T2D with an acceptable tolerability profile. Still, larger and longer studies are needed.

Phase 2 trial with imeglimin in patients with Type 2 diabetes indicates effects on insulin secretion and sensitivity

INTRODUCTION

The aim of the present study was to evaluate the effect of 18-week monotherapy with imeglimin on glucose tolerance and on insulin secretion/sensitivity in type 2 diabetic (T2D) patients.

METHODS

The study was an 18-week, double-blind clinical trial in T2D subjects previously treated with stable metformin therapy and washed out for 4 weeks. Subjects were randomized 1:1 to receive a 1500 mg bid of imeglimin or placebo. The primary endpoint was the effect of imeglimin vs placebo on changes from baseline to week 18 in glucose tolerance (glucose area under the curve [AUC]) during a 3 h-glucose tolerance test [OGTT]). Secondary endpoints included glycaemic control and calculated indices of insulin secretion and sensitivity.

RESULTS

A total of 59 subjects were randomized, 30 receiving imeglimin and 29 receiving placebo. The study met its primary endpoint. Least squares (LS) mean difference between treatment groups (imeglimin - placebo) for AUC glucose from baseline to week 18 was -429.6 mmol/L·min (p = .001). Two-hour post-dose fasting plasma glucose was significantly decreased with LS mean differences of -1.22 mmol/L (p = .022) and HbA1c was improved with LS mean differences of -0.62% (p = .013). The AUC_0-180min ratio C-peptide/glucose [LS mean differences of 0.041 nmol/mmol (p < .001)] and insulinogenic index were significantly increased by imeglimin treatment. The increase in insulin secretion was associated with an increase in beta-cell glucose sensitivity. Additionally, the insulin sensitivity indices derived from the OGTT Stumvoll (p = .001) and Matsuda (not significant) were improved in the imeglimin group vs placebo. Imeglimin was well tolerated with 26.7% of subjects presenting at least one treatment-emergent adverse event versus 58.6% of subjects in the placebo group.

CONCLUSIONS

Results are consistent with a mode of action involving insulin secretion as well as improved insulin sensitivity and further support the potential for imeglimin to improve healthcare in T2D patients.

The Effects of Imeglimin on the Daily Glycemic Profile Evaluated by Intermittently Scanned Continuous Glucose Monitoring: Retrospective, Single-Center, Observational Study

INTRODUCTION

Imeglimin is a novel antidiabetic drug that amplifies glucose-stimulated insulin secretion (GSIS) and improves insulin sensitivity. Several randomized clinical studies have shown the efficacy of imeglimin for glycemic control in patients with type 2 diabetes (T2D). We aimed to evaluate the short-term effects and safety of imeglimin in terms of glycemic control, as assessed by intermittently scanned continuous glucose monitoring (isCGM).

METHODS

This retrospective and observational study of 32 patients who were administered imeglimin in addition to existing treatment regimens was designed to evaluate glycemic profiles. The patients were monitored for more than 4 weeks, including the day of starting imeglimin. The changes in glycemic indices, including mean glucose level, coefficient of variation (CV), time in range (TIR) and time above range (TAR), before and after imeglimin administration were analyzed, and data on adverse effects were collected by interview.

RESULTS

Imeglimin administration significantly improved the mean values of glucose (from 159.0 ± 27.5 mg/dL to 141.7 ± 22.1 mg/dL; p < 0.001), TIR (from 67.9 ± 17.0% to 79.5 ± 13.3%; p < 0.001) and TAR (from 29.4 ± 17.5% to 17.9 ± 13.7%; p < 0.001) and tended to improve CV (from 29.0 ± 6.1 to 27.4 ± 5.58; p = 0.058). The curves of 24-h mean glucose level for all 32 subjects were shifted downward from the baseline after imeglimin administration. The high mean glucose level, high TAR, low TIR, low body mass index and low C-peptide were related to the efficacy of imeglimin for glycemic control. The main adverse effects were gastrointestinal disorders, and the incidence of hypoglycemia was increased in cases receiving a combination of imeglimin plus insulin or a glinide agent.

CONCLUSION

Imeglimin clearly shifted the daily glucose profile into an appropriate range in Japanese T2D patients, indicating improvement of short-term glycemic control. Imeglimin is thought to be a promising therapeutic agent for T2D patients, especially those with a low insulin secretory capacity, which is a common phenotype in East-Asian subjects with glucose intolerance.

Imeglimin Is Neuroprotective Against Ischemic Brain Injury in Rats-a Study Evaluating Neuroinflammation and Mitochondrial Functions

Imeglimin is a novel oral antidiabetic drug modulating mitochondrial functions. However, neuroprotective effects of this drug have not been investigated. The aim of this study was to investigate effects of imeglimin against ischemia-induced brain damage and neurological deficits and whether it acted via inhibition of mitochondrial permeability transition pore (mPTP) and suppression of microglial activation. Ischemia in rats was induced by permanent middle cerebral artery occlusion (pMCAO) for 48 h. Imeglimin (135 μg/kg/day) was injected intraperitoneally immediately after pMCAO and repeated after 24 h. Immunohistochemical staining was used to evaluate total numbers of neurons, astrocytes, and microglia as well as interleukin-10 (IL-10) producing cells in brain slices. Respiration of isolated brain mitochondria was assessed using high-resolution respirometry. Assessment of ionomycin-induced mPTP opening in intact cultured primary rat neuronal, astrocytic, and microglial cells was performed using fluorescence microscopy. Treatment with imeglimin significantly decreased infarct size, brain edema, and neurological deficits after pMCAO. Moreover, imeglimin protected against pMCAO-induced neuronal loss as well as microglial proliferation and activation, and increased the number of astrocytes and the number of cells producing anti-inflammatory cytokine IL-10 in the ischemic hemisphere. Imeglimin in vitro acutely prevented mPTP opening in cultured neurons and astrocytes but not in microglial cells; however, treatment with imeglimin did not prevent ischemia-induced mitochondrial respiratory dysfunction after pMCAO. This study demonstrates that post-stroke treatment with imeglimin exerts neuroprotective effects by reducing infarct size and neuronal loss possibly via the resolution of neuroinflammation and partly via inhibition of mPTP opening in neurons and astrocytes.

Reduced lactic acidosis risk with Imeglimin: Comparison with Metformin

The global prevalence of type 2 diabetes (T2D) is expected to exceed 642 million people by 2040. Metformin is a widely used biguanide T2D therapy, associated with rare but serious events of lactic acidosis, in particular with predisposing conditions (e.g., renal failure or major surgery). Imeglimin, a recently approved drug, is the first in a new class (novel mode of action) of T2D medicines. Although not a biguanide, Imeglimin shares a chemical moiety with Metformin and also modulates mitochondrial complex I activity, a potential mechanism for Metformin‐mediated lactate accumulation. We interrogated the potential for Imeglimin to induce lacticacidosis in relevant animal models and further assessed differences in key mechanisms known for Metformin's effects. In a dog model of major surgery, Metformin or Imeglimin (30–1000 mg/kg) was acutely administered, only Metformin‐induced lactate accumulation and pH decrease leading to lactic acidosis with fatality at the highest dose. Rats with gentamycin‐induced renal insufficiency received Metformin or Imeglimin (50–100 mg/kg/h), only Metformin increased lactatemia and H⁺ concentrations with mortality at higher doses. Plasma levels of Metformin and Imeglimin were similar in both models. Mice were chronically treated with Metformin or Imeglimin 200 mg/kg bid. Only Metformin produced hyperlactatemia after acute intraperitoneal glucose loading. Ex vivo measurements revealed higher mitochondrial complex I inhibition with Metformin versus slight effects with Imeglimin. Another mechanism implicated in Metformin's effects on lactate production was assessed: in isolated rat, liver mitochondria exposed to Imeglimin or Metformin, only Metformin (50–250 µM) inhibited the mitochondrial glycerol‐3‐phosphate dehydrogenase (mGPDH). In liver samples from chronically treated mice, measured mGPDH activity was lower with Metformin versus Imeglimin. These data indicate that the risk of lactic acidosis with Imeglimin treatment may be lower than with Metformin and confirm that the underlying mechanisms of action are distinct, supporting its potential utility for patients with predisposing conditions.

[Imeglimin: features of the mechanism of action and potential benefits]

Imeglimin is the first drug in a new class of tetrahydrotriazine-containing oral hypoglycemic agents called «glimines». Its mechanism of action is aimed at achieving a double effect, firstly, to improve the function of beta cells of the pancreas, and secondly, to enhance the action of insulin in key tissues, including the liver and skeletal muscles. At the cellular level, imeglimin modulates mitochondrial function, which leads to an improvement in cellular energy metabolism, as well as to the protection of cells from death in conditions of excessive accumulation of reactive oxygen species. It is important to note that the mechanism of action of imeglimin differs from existing drugs used for the treatment of type 2 diabetes mellitus. Like glucagon-like peptide-1 receptor agonists, imeglimin enhances insulin secretion in an exclusively glucose-dependent manner, but their mechanism of action at the cellular level diverges. Sulfonylureas and glinides function by closing ATP-sensitive potassium channels to release insulin, which is also different from imeglimin. Compared with metformin, the effect of imeglimine is also significantly different. Other major classes of oral antihypertensive agents, such as sodium-glucose transporter-2 inhibitors, thiazolidinediones and α glucosidase inhibitors mediate their action through mechanisms that do not overlap with imeglimine. Given such differences in the mechanisms of action, imeglimin can be used as part of combination therapy, for example with sitagliptin and metformin. The imeglimine molecule is well absorbed (Tmax-4), and the half-life is 5-6 hours, is largely excreted through the kidneys, and also has no clinically significant interactions with either metformin or sitagliptin.

Pharmacokinetics of Imeglimin in Caucasian and Japanese Healthy Subjects

BACKGROUND

Imeglimin is a first-in-class novel oral antidiabetic marketed in Japan as TWYMEEG^® to treat type 2 diabetes mellitus. Its mode of action is distinct from all other anti-hyperglycemic classes.

OBJECTIVE

To assess the pharmacokinetic and safety profile of imeglimin in Caucasian and Japanese healthy individuals.

METHODS

Two randomized placebo-controlled phase 1 clinical studies were conducted in Caucasian subjects after single (250-8000 mg) and multiple (250-2000 mg twice daily) ascending doses and in Japanese subjects after single (500-6000 mg) and multiple (500-2000 mg twice daily) ascending doses. Imeglimin plasma and urine concentrations were measured.

RESULTS

All imeglimin doses achieved maximal concentration between 1 and 3.5 h in Caucasians, and 1.5 and 3 h in Japanese subjects. The elimination half-lives (t_1/2) were dose-independent and means ranged between 9.03 and 20.2 h for Caucasians, and 4.45 and 12 h for Japanese subjects. Dose-normalized area under the plasma concentration-time curve decreased with dose in the 250-8000 mg and in the 500-6000 mg dose range in Caucasians and Japanese, respectively, suggesting a dose-dependent but less than dose-proportional effect in imeglimin exposure. Plasma accumulation was minimal following repeated dosing, and food did not affect the pharmacokinetics in either population. Exposures were generally similar between Caucasian and Japanese subjects with less than 20% difference, although there was a tendency for exposures in Japanese to be slightly higher. Imeglimin had an acceptable safety and tolerability profile, with dose-dependent mild gastrointestinal adverse events.

CONCLUSION

Imeglimin was safe and well tolerated in these two phases 1 studies, with pharmacokinetics comparable between the two populations.

CLINICAL TRIAL REGISTRATIONS

EudraCT 2005-001946-18 and 2014-004679-21.

Imeglimin Hydrochloride: First Approval

Imeglimin hydrochloride (TWYMEEG^®; hereafter referred to as imeglimin) is an orally administered, first-in-class glimin being developed by Poxel and, in several Asian countries, Sumitomo Dainippon Pharma for the treatment of type 2 diabetes (T2D). The glimins are a novel class of glucose-lowering agents that target multiple components of diabetes-associated pathology. In June 2021, imeglimin received its first approval for use in T2D in Japan. The Japanese approval was based on extensive preclinical and clinical data, including positive results from the pivotal phase III TIMES programme. This article summarizes the milestones in the development of imeglimin leading to this first approval for T2D.

Targeting Mitochondria in Diabetes

Type 2 diabetes (T2D), one of the most prevalent noncommunicable diseases, is often preceded by insulin resistance (IR), which underlies the inability of tissues to respond to insulin and leads to disturbed metabolic homeostasis. Mitochondria, as a central player in the cellular energy metabolism, are involved in the mechanisms of IR and T2D. Mitochondrial function is affected by insulin resistance in different tissues, among which skeletal muscle and liver have the highest impact on whole-body glucose homeostasis. This review focuses on human studies that assess mitochondrial function in liver, muscle and blood cells in the context of T2D. Furthermore, different interventions targeting mitochondria in IR and T2D are listed, with a selection of studies using respirometry as a measure of mitochondrial function, for better data comparison. Altogether, mitochondrial respiratory capacity appears to be a metabolic indicator since it decreases as the disease progresses but increases after lifestyle (exercise) and pharmacological interventions, together with the improvement in metabolic health. Finally, novel therapeutics developed to target mitochondria have potential for a more integrative therapeutic approach, treating both causative and secondary defects of diabetes.