Metformin's anticancer odyssey: Revealing multifaceted mechanisms across diverse neoplastic terrains- a critical review

Metformin, initially prescribed as an oral hypoglycemic medication for type 2 diabetes, has recently gained attention for its potential anticancer effects. Its history dates to 1918, when guanidine, a component of the traditional European herb Galega officinalis, was found to reduce glycemia. This review precisely examines the mechanisms underlying Metformin's anticancer effects across various neoplastic conditions. This investigation explores the complex interactions between metformin and major signaling pathways associated with carcinogenesis, including AMP-activated protein kinase (AMPK), mTOR, and insulin-like growth factor (IGF) pathways. The review emphasizes Metformin's diverse effects on angiogenesis, inflammation, apoptosis, and cellular metabolism in cancer cells. Additionally, new data on metformin's capacity to alter the tumor microenvironment and enhance immune surveillance systems against cancer are examined. The review underscores Metformin's potential for repurposing in oncology, emphasizing its clinical relevance as an adjuvant therapy for various cancers. The review provides insightful information about the complex anticancer mechanisms of metformin by combining data from preclinical and clinical studies. These findings not only broaden our knowledge of the effects of metformin but also open new avenues for oncology research and treatment developments.

New Perspectives on the Molecular Action of Metformin in the Context of Cellular Transduction and Adipogenesis

Metformin, a widely used antidiabetic drug, modulates the cellular physiology and metabolism of various body tissues, including adipose tissue. Adipogenesis, a complex process in which mesenchymal stem cells (MSC) differentiate into functional adipocytes, plays a key role in metabolic health and represents a potential therapeutic target for diverse metabolic disorders. Notably, recent evidence suggests that metformin modulates adipocyte differentiation. This narrative review explores the effects of metformin on cellular metabolism, with a particular focus on adipogenesis. The findings compiled in this review show that metformin regulates glucose and lipid metabolism in multiple tissues, including skeletal muscle, adipose tissue, liver, and intestine. Furthermore, metformin modulates adipogenesis through AMP-activated protein kinase (AMPK)-dependent and independent mechanisms in 3T3-L1 cells and adipose-derived stem cells. The review also emphasizes that metformin can promote or inhibit adipogenesis and lipid accumulation, depending on its concentration. Additionally, metformin attenuates inflammatory pathways by reducing the production of proinflammatory cytokines such as IL-6, MCP-1, and COX-2. Finally, evidence supports that vitamin D enhances the anti-inflammatory actions of metformin and promotes cell differentiation toward a beige adipocyte phenotype. In summary, this review examines the molecular actions of metformin to propose potential new therapeutic strategies for managing obesity and related metabolic diseases.

Leiurus quinquestratus venom promotes β islets regeneration and restores glucose level in streptozotocin induced type 2 diabetes mellitus in rats

Diabetes mellitus type 2 (T2-DM) is one of the most prevalent chronic metabolic diseases, marked by insulin resistance and a relative lack of insulin production. T2-DM can be treated using various methods; however, these treatments are risky for several vital organs. Subsequently, novel T2-DM replacement therapies should be discovered. The goal of this study was to see how efficient Leiurus quinquestratus venom (LQV) was as a diabetic medicine for the treatment of T2-DM in rats. The median lethal dose (LD50) of LQV has been determined. Then, forty male Sprague Dawley rats were divided into four groups (n = 10) as follows, with group 1 (Gp1) separated as a negative control. Gp2, Gp3, and Gp4 were fed a high-fat diet (HFD) for 12 weeks before receiving an intraperitoneal (i.p) injection of streptozotocin (STZ) as 30 mg/kg b.wt. Gp3 received metformin (Met) as 150 mg/kg b.wt i.p. LQV as 1/40 LD50 was given i.p. to Gp4. Treatments with Met or LQV were once every day for eight weeks. Hematological, biochemical, histopathological, and immunohistochemical studies were determined, along with the percentages of changes in total body weight. Results: LD50 of LQV was 0.3 mg/kg b.wt. Met or LQV treatment reduced hyperglycemia and C-peptide levels and lessened the hepato-renal biomarkers disorders in T2-DM rats. Intriguingly, histological analysis revealed that LQV treatment outperformed Met in improving and restoring β-cells in pancreatic tissues of T2-DM mice. In conclusion, this study demonstrated a new and promising method for treating T2-DM with LQV. Further investigation is required to isolate the bioactive elements from LQV to treat T2-DM.

Imeglimin, unlike metformin, does not perturb differentiation of human induced pluripotent stem cells towards pancreatic β-like cells and rather enhances gain in β cell identity gene sets

AIMS/INTRODUCTION

Metformin treatment for hyperglycemia in pregnancy (HIP) beneficially improves maternal glucose metabolism and reduces perinatal complications. However, metformin could impede pancreatic β cell development via impaired mitochondrial function. A new anti-diabetes drug imeglimin, developed based on metformin, improves mitochondrial function. Here we examine the effect of imeglimin on β cell differentiation using human induced pluripotent stem cell (iPSC)-derived pancreatic islet-like spheroid (SC-islet) models.

MATERIALS AND METHODS

Human iPSCs are differentiated into SC-islets by three-dimensional culture with and without imeglimin or metformin. Differentiation efficiencies of SC-islets were analyzed by flow cytometry, immunostaining, quantitative PCR, and insulin secretion assay. RNA sequencing and oxygen consumption rate were obtained for further characterization of SC-islets. SC-islets were cultured with proinflammatory cytokines, in part mimicking the uterus environment in HIP.

RESULTS

Metformin perturbed SC-islet differentiation while imeglimin did not alter it. Furthermore, imeglimin enhanced the gene expressions of β cell lineage markers. Maintenance of mitochondrial function and optimization of TGF-β and Wnt signaling were considered potential mechanisms for augmented β cell maturation by imeglimin. In the presence of proinflammatory cytokines, imeglimin ameliorated β cell differentiation impaired by cytokines and metformin.

CONCLUSIONS

Imeglimin does not perturb differentiation of SC-islet cells and rather enhances gain in β cell identity gene sets in contrast to metformin. This may lead to the improvement of in vitro β cell differentiation protocols.

Benefits and disadvantages of combination therapy with imeglimin and metformin in patients with type 2 diabetes

BACKGROUND

We retrospectively examined the benefits and disadvantages of adding imeglimin to metformin therapy in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Ninety-four patients with type 2 diabetes who had been administered imeglimin were included in the safety analysis set (SAS). Sixty-four patients who had been treated with imeglimin for over 6 months were included in the full analysis set (FAS). The primary outcome was the change in HbA1c levels in the FAS. The secondary outcomes were gastrointestinal adverse events (AEs) in the SAS and changes in body weight and FIB-4 in theFAS.

RESULTS

In the SAS, gastrointestinal AEs occurred in 15 of 40 (38%) metformin users and 6 of 54 (11%) non-users. In the FAS, HbA1c levels were significantly reduced in both metformin users (n = 27, baseline, 8.5 ± 1.1%;6 months, 7.7 ± 1.2%) and non-users (n = 37, baseline, 8.0 ± 0.9%; 6 months,7.4 ± 0.9%). While body weight (from 72.0 ± 20.5 kg to 70.9 ± 20.8 kg) and FIB-4 (from 1.27 ± 0.57 to 1.17 ± 0.49) significantly decreased in metformin users, they did not significantly differ in non-users.

CONCLUSIONS

Adding imeglimin to metformin therapy demonstrated favorable reductions in HbA1c, body weight, and FIB-4 in patients with type 2 diabetes, although it was associated with the incidence of gastrointestinal AEs.

TRIAL REGISTRATION

UMIN000055241.

Forced Degradation Study of an Anti-Diabetic Drug Imeglimin: Impurity Profiling and Structure Elucidation Using LC-Q-ToF-MS/MS and NMR

RATIONALE

The present study aims to establish structures of the degradation products of an anti-diabetic drug, Imeglimin (IMG) approved for the treatment of type 2 diabetes mellitus in the year 2021. Degradation pathways are proposed along with in silico toxicity assessments of the observed degradation products (DPs) of the drug.

METHODS

A reversed-phase high-performance liquid chromatography (RP-HPLC), equipped with a photodiode array detector, was used to separate the observed DPs with a Phenomenex Luna PFP (250 × 4.6 mm, 5 μm) column, using 10 mM ammonium formate (pH 4.5) and methanol as mobile phase. Liquid chromatography quadrupole time of flight mass spectrometry (LC-Q-ToF-MS/MS) and nuclear magnetic resonance (NMR) spectroscopy were employed for structural elucidation. Zeneth and Derek suites were used for in silico assessments.

RESULTS

A total of four degradation products were observed, which were successfully separated on an RP-HPLC. The structural characterization of three of the four DPs was achieved using LC-Q-TOF-MS/MS by employing electro spray ionization as well as atmospheric pressure chemical ionization. Additionally, DP-3 was isolated using a preparative HPLC and was characterized by NMR. Computationally predicted structures were compared with the experimental observations.

CONCLUSION

An HPLC method, capable of separating the Imeglimin and its four DPs, was developed and validated as per the ICH Q2(R1) guideline. Structure elucidation reveals a variety of products with metformin as one of the identified DPs along with a metabolite. The toxicity potential of DPs was assessed through docking studies.

Efficacy of imeglimin treatment versus metformin dose escalation on glycemic control in subjects with type 2 diabetes treated with a dipeptidyl peptidase-4 inhibitor plus low-dose metformin: A multicenter, prospective, randomized, open-label, parallel-group comparison study (MEGMI study)

AIMS

To compare the efficacy of adding imeglimin versus that of metformin dose escalation on glycemic control in subjects with type 2 diabetes treated with a dipeptidyl peptidase-4 inhibitor plus low-dose metformin (500-1000 mg/day).

MATERIALS AND METHODS

In this multicentre, open-labelled, prospective, randomized, parallel-group comparison study, the addition of imeglimin (2000 mg/day) or metformin escalation was applied for 24 weeks in eligible subjects. The primary endpoint was the mean change in glycated haemoglobin (HbA1c) over 24 weeks. As the secondary endpoints, the occurrence of adverse events, changes in metabolic parameters, biomarkers and factors associated with HbA1c improvement were analysed.

RESULTS

Seventy-three eligible subjects were enrolled. Of them, 65 participants comprised the full analysis set. At 24 weeks, the addition of imeglimin (n = 33) resulted in greater improvement in HbA1c compared with metformin dose escalation (n = 32) (from 7.61 ± 0.48% to 6.93 ± 0.49% in imeglimin and from 7.56 ± 0.61% to 7.09 ± 0.56% in metformin escalation; change difference: -0.21% [95% confidence interval: -0.41%, -0.01%] [p = 0.038]); however, seven subjects in the imeglimin group discontinued imeglimin because of serious adverse events on gastrointestinal tract. In intra-group pre/post comparisons, imeglimin treatment significantly reduced body weight and improved liver enzyme elevation. There was a significant correlation between improvement levels of HbA1c and indicators of fatty liver disease in the imeglimin group.

CONCLUSIONS

Imeglimin in combination with a dipeptidyl peptidase-4 inhibitor and low-dose metformin improved HbA1c compared with metformin dose escalation.

Differential effects of imeglimin and metformin on insulin and incretin secretion-An exploratory randomized controlled trial

AIMS

Imeglimin is a new oral anti-diabetic drug with a similar structure to that of metformin; however, unlike metformin, clinical trials indicate that imeglimin elicits its glucose-lowering effect mainly by enhancement of insulin secretion. The comparative effects of the two drugs on incretin secretion remains to be elucidated.

MATERIALS AND METHODS

A single-center, open-label, randomized controlled trial was conducted in patients with type 2 diabetes who were drug-naïve or were on a single oral hypoglycaemic agent (OHA). For patients taking a single OHA, an 8-week washout period was employed before randomization. Participants were randomized to the imeglimin group (IME, 2000 mg/day) or the metformin group (MET, 1000 mg/day), and OGTT was performed before treatment and after 12 and 24 weeks of treatment.

RESULTS

The reduction in HbA1c at 24 weeks was similar in IME and MET. OGTT revealed a comparable decrease in post-challenge blood glucose excursion in both groups, but insulin levels were increased only in IME. Total and active glucagon-like peptide-1 (GLP-1) levels were increased in both IME and MET; however, total and active glucose-dependent insulinotropic peptide (GIP) levels were increased only in IME. Interestingly, while an increase in insulin levels in IME was positively correlated with an increase in GLP-1 at 12 weeks, it was correlated only with an increase in GIP at 24 weeks.

CONCLUSIONS

Unlike metformin, imeglimin enhances GIP secretion as well as GLP-1 secretion, in addition to its direct insulinotropic mechanism of glucose control, emphasizing its potential as a therapeutic option in the treatment of patients with diabetes.

Moringa oleifera in a modern time: A comprehensive review of its nutritional and bioactive composition as a natural solution for managing diabetes mellitus by reducing oxidative stress and inflammation

Globally, diabetes mellitus (DM) and its complications are considered among the most significant public health problems. According to numerous scientific studies, Plants and their bioactive compounds may reduce inflammation and oxidative stress (OS), leading to a reduction in the progression of DM. Moringa oleifera (MO), widely used in Ayurvedic and Unani medicine for centuries because of its health-promoting characteristics, particularly its ability to control DM and its related complications. MO is a multi-purpose plant that has an impressive range of nutritional components including proteins, amino acids (Essential and non-essential amino acids), carbs, fats, fiber, vitamins, and phenolic compounds. In the modern era, scientists have paid close attention to the anti-diabetic, anti-oxidative and anti-inflammatory attributes and other medicinal properties, of MO leaves and seeds. MO leaves and seeds have modulatory effects on DM that are likely influenced by multiple mechanisms. Some of these mechanisms include direct effects, but other mechanisms involve inhibition the production of inflammatory markers, modulation of the gut microbiome, reduction of OS, enhancement of glucose metabolism through hexokinase and glucose 6-phosphate dehydrogenase, improve insulin sensitivity and glucose uptake in the liver and muscles. Overall, these findings suggest that MO may play a role in lowering the risk of DM and its related outcomes. The purpose of this review is to provide a comprehensive overview of the nutritional and bioactive profiles of MO leaves and seeds, as well as to investigate their possible anti-diabetic effects by modulating oxidative stress and inflammation. Our results indicate that MO may be a beneficial natural resource for management of DM and related issues by lowering oxidative stress and inflammation. Furthermore, studies on MO has yielded promising findings in diabetic animal models, indicating antioxidant and anti-inflammatory properties. However, human trials have shown less solid results, most likely due to a lack of studies, different techniques, and dosages. More clinical research is needed to fully understand MO's anti-diabetic potential, notably in lowering oxidative stress and inflammation, both of which are critical in controlling diabetes complications.

Clinical research framework proposal for ketogenic metabolic therapy in glioblastoma

Glioblastoma (GBM) is the most aggressive primary brain tumor in adults, with a universally lethal prognosis despite maximal standard therapies. Here, we present a consensus treatment protocol based on the metabolic requirements of GBM cells for the two major fermentable fuels: glucose and glutamine. Glucose is a source of carbon and ATP synthesis for tumor growth through glycolysis, while glutamine provides nitrogen, carbon, and ATP synthesis through glutaminolysis. As no tumor can grow without anabolic substrates or energy, the simultaneous targeting of glycolysis and glutaminolysis is expected to reduce the proliferation of most if not all GBM cells. Ketogenic metabolic therapy (KMT) leverages diet-drug combinations that inhibit glycolysis, glutaminolysis, and growth signaling while shifting energy metabolism to therapeutic ketosis. The glucose-ketone index (GKI) is a standardized biomarker for assessing biological compliance, ideally via real-time monitoring. KMT aims to increase substrate competition and normalize the tumor microenvironment through GKI-adjusted ketogenic diets, calorie restriction, and fasting, while also targeting glycolytic and glutaminolytic flux using specific metabolic inhibitors. Non-fermentable fuels, such as ketone bodies, fatty acids, or lactate, are comparatively less efficient in supporting the long-term bioenergetic and biosynthetic demands of cancer cell proliferation. The proposed strategy may be implemented as a synergistic metabolic priming baseline in GBM as well as other tumors driven by glycolysis and glutaminolysis, regardless of their residual mitochondrial function. Suggested best practices are provided to guide future KMT research in metabolic oncology, offering a shared, evidence-driven framework for observational and interventional studies.

Trends in Antidiabetic Drug Use and Safety of Metformin in Diabetic Patients with Varying Degrees of Chronic Kidney Disease from 2010 to 2021 in Korea: Retrospective Cohort Study Using the Common Data Model

BACKGROUND/OBJECTIVES

This study aimed to investigate trends in antidiabetic drug use and assess the risk of metformin-associated lactic acidosis (MALA) in patients with chronic kidney disease (CKD).

METHODS

A retrospective observational analysis based on the common data model was conducted using electronic medical records from 2010 to 2021. The patients included were aged ≥18, diagnosed with CKD and type 2 diabetes, and had received antidiabetic medications for ≥30 days. MALA was defined as pH ≤ 7.35 and arterial lactate ≥4 mmol/L.

RESULTS

A total of 8318 patients were included, with 6185 in CKD stages 1-2 and 2133 in stages 3a-5. Metformin monotherapy was the most prescribed regimen, except in stage 5 CKD. As CKD progressed, metformin use significantly declined; insulin and meglitinides were most frequently prescribed in end-stage renal disease. Over the study period, the use of SGLT2 inhibitors (13.3%) and DPP-4 inhibitors (24.5%) increased significantly, while sulfonylurea use decreased (p < 0.05). Metformin use remained stable in earlier CKD stages but significantly decreased in stage 3b or worse. The incidence rate (IR) of MALA was 1.22 per 1000 patient-years, with a significantly increased IR in stage 4 or worse CKD (p < 0.001).

CONCLUSIONS

Metformin was the most prescribed antidiabetic drug in CKD patients in Korea with a low risk of MALA. Antidiabetic drug use patterns varied across CKD stages, with a notable decline in metformin use in advanced CKD and a rise in SGLT2 inhibitor prescriptions, underscoring the need for further optimized therapy.

Imeglimin enhances glucagon secretion through an indirect mechanism and improves fatty liver in high-fat, high-sucrose diet-fed mice

AIMS/INTRODUCTION

Imeglimin is a recently approved oral antidiabetic agent that improves insulin resistance, and promotes insulin secretion from pancreatic β-cells. Here, we investigated the effects of imeglimin on glucagon secretion from pancreatic α-cells.

MATERIALS AND METHODS

Experiments were carried out in high-fat, high-sucrose diet-fed mice. The effects of imeglimin were examined using insulin and glucose tolerance tests, glucose clamp studies, and measurements of glucagon secretion from isolated islets. Glucagon was measured using both the standard and the sequential protocol of Mercodia sandwich enzyme-linked immunosorbent assay; the latter eliminates cross-reactivities with other proglucagon-derived peptides.

RESULTS

Plasma glucagon, insulin and glucagon-like peptide-1 levels were increased by imeglimin administration in high-fat, high-sucrose diet-fed mice. Glucose clamp experiments showed that the glucagon increase was not caused by reduced blood glucose levels. After both single and long-term administration of imeglimin, glucagon secretions were significantly enhanced during glucose tolerance tests. Milder enhancement was observed when using the sequential protocol. Long-term administration of imeglimin did not alter α-cell mass. Intraperitoneal imeglimin administration did not affect glucagon secretion, despite significantly decreased blood glucose levels. Imeglimin did not enhance glucagon secretion from isolated islets. Imeglimin administration improved fatty liver by suppressing de novo lipogenesis through decreasing sterol regulatory element binding protein-1c and carbohydrate response element binding protein and their target genes, while enhancing fatty acid oxidation through increasing carnitine palmitoyltransferase I.

CONCLUSIONS

Overall, the present results showed that imeglimin enhances glucagon secretion through an indirect mechanism. Our findings also showed that glucagon secretion promoted by imeglimin could contribute to improvement of fatty liver through suppressing de novo lipogenesis and enhancing fatty acid oxidation.

Advancing the understanding of diabetic encephalopathy through unravelling pathogenesis and exploring future treatment perspectives

Diabetic encephalopathy (DE), a significant micro-complication of diabetes, manifests as neurochemical, structural, behavioral, and cognitive alterations. This condition is especially dangerous for the elderly because aging raises the risk of neurodegenerative disorders and cognitive impairment, both of which can be made worse by diabetes. Despite its severity, diagnosis of this disease is challenging, and there is a paucity of information on its pathogenesis. The pivotal roles of various cellular pathways, activated or influenced by hyperglycemia, insulin sensitivity, amyloid accumulation, tau hyperphosphorylation, brain vasculopathy, neuroinflammation, and oxidative stress, are widely recognized for contributing to the potential causes of diabetic encephalopathy. We also reviewed current pharmacological strategies for DE encompassing a comprehensive approach targeting metabolic dysregulations and neurological manifestations. Antioxidant-based therapies hold promise in mitigating oxidative stress-induced neuronal damage, while anti-diabetic drugs offer neuroprotective effects through diverse mechanisms, including modulation of insulin signaling pathways and neuroinflammation. Additionally, tissue engineering and nanomedicine-based approaches present innovative strategies for targeted drug delivery and regenerative therapies for DE. Despite significant progress, challenges remain in translating these therapeutic interventions into clinical practice, including long-term safety, scalability, and regulatory approval. Further research is warranted to optimize these approaches and address remaining gaps in the management of DE and associated neurodegenerative disorders.

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.

Imeglimin attenuates NLRP3 inflammasome activation by restoring mitochondrial functions in macrophages

Imeglimin is a novel oral antidiabetic drug for treating type 2 diabetes. However, the effect of imeglimin on NLRP3 inflammasome activation has not been investigated yet. Here, we aimed to investigate whether imeglimin reduces LPS-induced NLRP3 inflammasome activation in THP-1 macrophages and examine the associated underlying mechanisms. We analyzed the mRNA and protein expression levels of NLRP3 inflammasome components and IL-1β secretion. Additionally, reactive oxygen species (ROS) generation, mitochondrial membrane potential, and mitochondrial permeability transition pore (mPTP) opening were measured by flow cytometry. Imeglimin inhibited NLRP3 inflammasome-mediated IL-1β production in LPS-stimulated THP-1-derived macrophages. In addition, imeglimin reduced LPS-induced mitochondrial ROS production and mitogen-activated protein kinase phosphorylation. Furthermore, imeglimin restored the mitochondrial function by modulating mitochondrial membrane depolarization and mPTP opening. We demonstrated for the first time that imeglimin reduces LPS-induced NLRP3 inflammasome activation by inhibiting mPTP opening in THP-1 macrophages. These results suggest that imeglimin could be a promising new anti-inflammatory agent for treating diabetic complications.

Synthesis and molecular docking studies of new aryl imeglimin derivatives as a potent antidiabetic agent in a diabetic zebrafish model

Diabetes mellitus (DM) is a persistent, progressive, and multifaceted disease characterized by elevated blood glucose levels. Type 2 diabetes mellitus is associated with a relative deficit in insulin mainly due to beta cell dysfunction and peripheral insulin resistance. Metformin has been widely prescribed as a primary treatment option to address this condition. On the other hand, an emerging glucose-reducing agent known as imeglimin has garnered attention due to its similarity to metformin in terms of chemical structure. In this study, an innovative series of imeglimin derivatives, labeled 3(a-j), were synthesized through a one-step reaction involving an aldehyde and metformin. The chemical structures of these derivatives were thoroughly characterized using ESI-MS, 1H, and 13C NMR spectroscopy. In vivo tests on a zebrafish diabetic model were used to evaluate the efficacy of the synthesized compounds. All compounds 3(a-j) showed significant antidiabetic effects. It is worth mentioning that compounds 3b (FBS = 72.3 ± 7.2 mg/dL) and 3g (FBS = 72.7 ± 4.3 mg/dL) have antidiabetic effects comparable to those of the standard drugs metformin (FBS = 74.0 ± 5.1 mg/dL) and imeglimin (82.3 ± 5.2 mg/dL). In addition, a docking study was performed to predict the possible interactions between the synthesized compounds and both SIRT1 and GSK-3β targets. The docking results were in good agreement with the experimental assay results.

Imeglimin improves systemic metabolism by targeting brown adipose tissue and gut microbiota in obese model mice

Imeglimin is a recently developed anti-diabetic drug that could concurrently promote insulin secretion and insulin sensitivity, while its mechanisms of action are not fully understood. Here we show that imeglimin administration could protect mice from high fat diet-induced weight gain with enhanced energy expenditure and attenuated whitening of brown adipose tissue. Imeglimin administration led to significant alteration of gut microbiota, which included an increase of Akkermansia genus, with attenuation of obesity-associated gut pathologies. Ablation of microbiota by antibiotic treatment partially abrogated the insulin sensitizing effects of imeglimin, while not affecting its actions on body weight gain or brown adipose tissue. Collectively, our results characterize imeglimin as a potential agent promoting energy expenditure and gut integrity, providing new insights into its mechanisms of action.

Non-Insulin-Based Drug Entities Used to Treat Diabetes Type 2 Disease (T2DM), Based on Natural Products from All Sources

Diabetes type 2 (T2DM) is the non-insulin-linked disease that is now becoming a major problem not only in the West but also in Asia (particularly in China and close geographic areas). Unlike the childhood onset diabetic disease (T1DM), which is effectively due to lack of insulin production and is maintained by insulin injection, T2DM is best thought of as an adult disease often being caused by what is now considered "metabolic syndrome" or the culmination of too many insults to the body, in particular obesity and its "coupled diseases" including heart problems. Its symptoms were described in ancient times not only in Europe but also in Asia and with later (1600s) anecdotal reports from South America. In all cases, the diagnostic was "sweet urine" due to the excretion of large amounts of glucose in the urine. This review covers the non-insulin agents approved from 1990 to 2021 from a historical aspect and discussions of the latest agents and can be considered an extension of the author's previous drug source reviews, but this time concentrating on nominally one disease entity, though metabolic syndrome is a collection of ailments.

Imeglimin mitigates the accumulation of dysfunctional mitochondria to restore insulin secretion and suppress apoptosis of pancreatic β-cells from db/db mice

Mitochondrial dysfunction in pancreatic β-cells leads to impaired glucose-stimulated insulin secretion (GSIS) and type 2 diabetes (T2D), highlighting the importance of autophagic elimination of dysfunctional mitochondria (mitophagy) in mitochondrial quality control (mQC). Imeglimin, a new oral anti-diabetic drug that improves hyperglycemia and GSIS, may enhance mitochondrial activity. However, chronic imeglimin treatment's effects on mQC in diabetic β-cells are unknown. Here, we compared imeglimin, structurally similar anti-diabetic drug metformin, and insulin for their effects on clearance of dysfunctional mitochondria through mitophagy in pancreatic β-cells from diabetic model db/db mice and mitophagy reporter (CMMR) mice. Pancreatic islets from db/db mice showed aberrant accumulation of dysfunctional mitochondria and excessive production of reactive oxygen species (ROS) along with markedly elevated mitophagy, suggesting that the generation of dysfunctional mitochondria overwhelmed the mitophagic capacity in db/db β-cells. Treatment with imeglimin or insulin, but not metformin, reduced ROS production and the numbers of dysfunctional mitochondria, and normalized mitophagic activity in db/db β-cells. Concomitantly, imeglimin and insulin, but not metformin, restored the secreted insulin level and reduced β-cell apoptosis in db/db mice. In conclusion, imeglimin mitigated accumulation of dysfunctional mitochondria through mitophagy in diabetic mice, and may contribute to preserving β-cell function and effective glycemic control in T2D.

Chondroitin Sulfate-Derived Micelles for Adipose Tissue-Targeted Delivery of Celastrol and Phenformin to Enhance Obesity Treatment

Adipose tissue macrophages (ATMs) are crucial in maintaining a low-grade inflammatory microenvironment in adipose tissues (ATs). Modulating ATM polarization to attenuate inflammation represents a potential strategy for treating obesity with insulin resistance. This study develops a combination therapy of celastrol (CLT) and phenformin (PHE) using chondroitin sulfate-derived micelles. Specifically, CLT-loaded 4-aminophenylboronic acid pinacol ester-modified chondroitin sulfate micelle (CS-PBE/CLT) and chondroitin sulfate-phenformin conjugate micelles (CS-PHE) were synthesized, which were shown to actively target ATs through CD44-mediated pathways. Furthermore, the dual micellar systems significantly reduced inflammation and lipid accumulation via protein quantification and Oil Red O staining. In preliminary in vivo studies, we performed H&E staining, immunohistochemical staining, insulin tolerance test, and glucose tolerance test, and the results showed that the combination therapy using CS-PBE/CLT and CS-PHE micelles significantly reduced the average body weight, white adipose tissue mass, and liver mass of high-fat diet-fed mice while improving their systemic glucose homeostasis. Overall, this combination therapy presents a promising alternative to current treatment options for diet-induced obesity.

Characteristics and Biological Properties of Imeglimin Hydrochlo ride, A Novel Antidiabetic Agent: A Systematic Review

BACKGROUND

WHO indicates that diabetes will become the 7th leading reason for death by 2030. The physiopathology of dysfunctioning is associated with obesity, weight gain and predominantly insulin resistance in insulin-sensitive cells and continuous deterioration of pancreatic beta cell function..Imeglimin is an investigational novel oral anti-diabetic drug.

OBJECTIVES

The motive of the review is to comprehensively explore the chemistry, biological and analytical analysis of the Imeglimin hydrochloride.

METHODS

To enhance the understanding, a systematic review was conducted by forming a database of relevant existing studies from electronic resources like Web of Science, ScienceDirect and PubMed. The methodology is reflected in the PRISMA design.

RESULT

The drug was approved in the year 2021 for therapeutic purposes in Japan. It is the novel and first approved drug for this type of Anti-diabetic treatment. It is a small molecular drug whose molecular weight is 191.6 grams per mole utilized for oral administration. Imeglimin is thought to have both activities, as the amount of glucose is dependent on insulin secretory impact and insulin sensitivity is increased.

CONCLUSION

Therapeutic, pharmacological, and analytical considerations for the novel drug Imeglimin hydrochloride are discussed in this review.

Imeglimin: the New Kid on the Block

PURPOSE OF REVIEW

This review aims to collect all the data regarding imeglimin and present it as one of the options for managing diabetes.

RECENT FINDINGS

It is a new drug that has recently been approved as an oral anti-diabetic drug, either as monotherapy or in combination with other oral antidiabetic drugs including insulin, with modest HbA1c reduction, and a fairly safe profile. Imeglimin was first approved in 2021 in Japan and China and is available in India from October 2022. Imeglimin is the first compound in a new class of oral anti-diabetic medications known as "glimins" that include a tetrahydrotriazine ring. Glimins act by amplifying glucose-stimulated insulin secretion (GSIS) and preserving β-cell mass, leading to augmented insulin secretion. Furthermore, It also intensifies insulin action by inhibiting of hepatic glucose output and recovery of altered insulin signalling in both hepatocytes (liver) and myocytes (skeletal muscle). This is a unique mode of action than has been demonstrated to be distinct from other classes of drugs, as it targets both insulin secretion and insulin resistance by correcting the mitochondrial dysfunction. Imeglimin has been studied in various phase III trials which have equivocally shown it to be effective in lowering glucose levels and improving pancreatic function and its recommended dose set at 1000 mg bid.

Melatonin and metformin co-loaded nanoliposomes efficiently attenuate liver damage induced by bile duct ligation in rats

In the current study, the therapeutic effectiveness of the metformin (Met) and melatonin (Mel) co-loaded liposomes was investigated on cholestasis induced by bile duct ligation (BDL) in male rats. Histopathological analysis, biochemical analysis, and oxidative stress markers were assayed to determine the therapeutic effect of Met and Mel co-loaded liposomes on cholestasis. Histopathological analysis revealed that the simultaneous administration of Met and Mel, whether in the free (C-Mel-Met) or liposomal (C-Lipo-Mel-Met) forms, reduced inflammation as well as proliferation of bile ducts; however, results were more prominent in the liposomal form of Mel and Met. Additionaly, serum levels of aspartate aminotransferase (AST) were significantly (p < 0.001) higher in (C-Mel-Met) treated rats compared with (BDL) rats; however, (C-Lipo-Mel-Met) treated rats exhibited significant (p < 0.05) lower AST rates in comparison to (BDL) rats. Moreover, a significant (p < 0.0001) drop in bilirubin levels was detected in (C-Lipo-Mel-Met) treated rats in comparison to (BDL) rats; it is noteworthy mentioning that bilirubin levels in (C-Lipo-Mel-Met) treated rats were insignificant in comparison to sham-control (SC) rats. Furthermore, rats concomitantly administered Met and Mel, exhibited significant downregulation in the expression levels of inflammatory cytokine genes such as TNF-α and IL-1 gene expression, where the downregulation was more prominent in the liposomal from. Our findings demonestrate that the concomitant administration of metformin and melatonin in the liposomal form had more therapeutic effect on liver injury than their free forms through improving histological changes, reducing biochemical markers and favoring oxidant- antioxidant balance.

Comparison of SGLT1, SGLT2, and Dual Inhibitor biological activity in treating Type 2 Diabetes Mellitus

Diabetes Mellitus Type 2 (T2D) is an emerging health burden in the USand worldwide, impacting approximately 15% of Americans. Current front-line therapeutics for T2D patients include sulfonylureas that act to reduce A1C and/or fasting blood glucose levels, or Metformin that antagonizes the action of glucagon to reduce hepatic glucose production. Next generation glucomodulatory therapeutics target members of the high-affinity glucose transporter Sodium-Glucose-Linked-Transporter (SGLT) family. SGLT1 is primarily expressed in intestinal epithelium, whose inhibition reduces dietary glucose uptake, whilst SGLT2 is highly expressed in kidney - regulating glucose reabsorption. A number of SGLT2 inhibitors are FDA approved whilst SGLT1 and dual SGLT1 & 2 inhibitor are currently in clinical trials. Here, we discuss and compare SGLT2, SGLT1, and dual inhibitors' biochemical mechanism and physiological effects.

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.

Molecular Mechanisms of Obesity-Induced Development of Insulin Resistance and Promotion of Amyloid-β Accumulation: Dietary Therapy Using Weak Organic Acids via Improvement of Lowered Interstitial Fluid pH

Insulin resistance is one of the etiologies of type 2 diabetes mellitus (T2DM) and has been suggested to contribute to the development of Alzheimer's disease by promoting amyloid-β accumulation. Various causes of insulin resistance have been suggested; however, mechanisms of insulin resistance development remain to be elucidated in many respects. Elucidating the mechanisms underlying the development of insulin resistance is one of the key factors in developing methods to prevent the onset of T2DM and Alzheimer's disease. It has been suggested that the body pH environment plays an important role in the control of cellular functions by regulating the action of hormones including insulin and the activity of enzymes and neurons, thereby maintaining homeostatic conditions of the body. This review introduces: (1) Mitochondrial dysfunction through oxidative stress caused by obesity-induced inflammation. (2) Decreased pH of interstitial fluid due to mitochondrial dysfunction. (3) Development of insulin resistance due to diminution of insulin affinity to its receptor caused by the lowered interstitial fluid pH. (4) Accelerated accumulation of amyloid-β due to elevated activities of β- and γ-secretases caused by the lowered interstitial fluid pH. (5) Diet therapies for improving insulin resistance with weak organic acids that act as bases in the body to raise the pH of lowered interstitial fluid and food factors that promote absorption of weak organic acids in the gut.

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.

Effects of imeglimin on mitochondrial function, AMPK activity, and gene expression in hepatocytes

Imeglimin is a recently launched antidiabetic drug structurally related to metformin. To provide insight into the pharmacological properties of imeglimin, we investigated its effects on hepatocytes and compared them with those of metformin. The effects of imeglimin on mitochondrial function in HepG2 cells or mouse primary hepatocytes were examined with an extracellular flux analyzer and on gene expression in HepG2 cells by comprehensive RNA-sequencing analysis. The effects of the drug on AMPK activity in HepG2 cells, mouse primary hepatocytes, and mouse liver were also examined. Treatment of HepG2 cells or mouse primary hepatocytes with imeglimin reduced the oxygen consumption rate coupled to ATP production. Imeglimin activated AMPK in these cells whereas the potency was smaller than metformin. Bolus administration of imeglimin in mice also activated AMPK in the liver. Whereas the effects of imeglimin and metformin on gene expression in HepG2 cells were similar overall, the expression of genes encoding proteins of mitochondrial respiratory complex III and complex I was upregulated by imeglimin but not by metformin. Our results suggest that imeglimin and metformin exert similar pharmacological effects on mitochondrial respiration, AMPK activity, and gene expression in cultured hepatocytes, whereas the two drugs differ in their effects on the expression of certain genes related to mitochondrial function.

Add-on imeglimin versus metformin dose escalation regarding glycemic control in patients with type 2 diabetes treated with a dipeptidyl peptidase-4 inhibitor plus low-dose metformin: study protocol for a multicenter, prospective, randomized, open-label, parallel-group comparison study (MEGMI study)

INTRODUCTION

Imeglimin is a novel anti-hyperglycemic drug that improves both insulin resistance and insulin secretion. The effects of imeglimin on glycemic control were confirmed in phase III clinical trials, but little is known about its effectiveness in daily clinical practice settings, especially compared with metformin. Therefore, we aim to clarify the efficacy of imeglimin in patients with type 2 diabetes (T2D) being treated with a dipeptidyl peptidase-4 (DPP-4) inhibitor plus low-dose metformin.

RESEARCH DESIGN AND METHODS

This is a multicenter, randomized, prospective, open-label, parallel-group trial. Seventy participants with T2D treated with a DPP-4 inhibitor plus metformin (500-1000 mg/day) for more than 12 weeks and a glycated hemoglobin (HbA1c) level of 52-85 mmol/mol (7.0%-9.9%) will be randomized to receive add-on imeglimin 1000 mg two times per day or metformin dose escalation for 24 weeks. Biochemical analyses and physical assessments will be performed at baseline and at the end of the study, and adverse events will be recorded. The primary endpoint is the change in HbA1c after 24 weeks. The secondary endpoints comprise the changes in blood pressure, pulse rate, body weight, abdominal circumference, and other laboratory parameters; the relationship between improvements of biological parameters including glycemic control and patient background characteristics; and side effects.

RESULTS

This study will reveal new insights into the incorporation of imeglimin into the diabetes treatment strategy.

CONCLUSIONS

This will be the first randomized controlled trial to compare the efficacy of adding imeglimin versus metformin dose escalation on glycemic control in patients with T2D.

TRIAL REGISTRATION NUMBER

jRCT1011220005.

Metformin: Activation of 5' AMP-activated protein kinase and its emerging potential beyond anti-hyperglycemic action

Metformin is a plant-based drug belonging to the class of biguanides and is known to treat type-2 diabetes mellitus (T2DM). The drug, combined with controlling blood glucose levels, improves the body's response to insulin. In addition, trials have identified the cardioprotective potential of metformin in the diabetic population receiving the drug. Activation of 5' AMP-activated protein kinase (AMPK) is the major pathway for these potential beneficial effects of metformin. Historically, much emphasis has been placed on the potential indications of metformin beyond its anti-diabetic use. This review aims to appraise other potential uses of metformin primarily mediated by the activation of AMPK. We also discuss various mechanisms, other than AMPK activation, by which metformin could produce beneficial effects for different conditions. Databases including PubMed/MEDLINE and Embase were searched for literature relevant to the review's objective. Reports from both research and review articles were considered. We found that metformin has diverse effects on the human body systems. It has been shown to exert anti-inflammatory, antioxidant, cardioprotective, metabolic, neuroprotective, anti-cancer, and antimicrobial effects and has now even been identified as effective against SARS-CoV-2. Above all, the AMPK pathway has been recognized as responsible for metformin's efficiency and effectiveness. Owing to its extensive potential, it has the capability to become a part of treatment regimens for diseases apart from T2DM.

A Review on the Antidiabetic Properties of Moringa oleifera Extracts: Focusing on Oxidative Stress and Inflammation as Main Therapeutic Targets

Moringa oleifera is one of the popular plants that have shown significant health benefits. Certainly, preclinical evidence (predominantly from animal models) summarized in the current review supports the beneficial effects of Moringa oleifera leaf extracts in combating the prominent characteristic features of diabetes mellitus. This includes effective control of blood glucose or insulin levels, enhancement of insulin tissue sensitivity, improvement of blood lipid profiles, and protecting against organ damage under sustained conditions of hyperglycemia. Interestingly, as major complications implicated in the progression of diabetes, including organ damage, Moringa oleifera leaf and seed extracts could efficiently block the detrimental effects of oxidative stress and inflammation in these preclinical models. Notably, these extracts (especially leaf extracts) showed enhanced effects in strengthening intracellular antioxidant defences like catalase, superoxide dismutase, and glutathione to lower lipid peroxidation products and reduce prominent pro-inflammatory markers such as tumor necrosis factor-α, interleukin (1L)-β, IL-6, monocyte chemoattractant protein-1 and nitric oxide synthase. From animal models of diabetes, the common and effective dose of leaf extracts of Moringa oleifera was 100-300 mg/kg, within the treatment duration of 2-8 weeks. Whereas supplementation with approximately 20 g leaf powder of Moringa oleifera for at least 2 weeks could improve postprandial blood glucose in subjects with prediabetes or diabetes. Although limited clinical studies have been conducted on the antidiabetic properties of Moringa oleifera, current findings provide an important platform for future research directed at developing this plant as a functional food to manage diabetic complications.

Tumor necrosis factor induces pathogenic mitochondrial ROS in tuberculosis through reverse electron transport

Tumor necrosis factor (TNF) is a critical host resistance factor against tuberculosis. However, excess TNF produces susceptibility by increasing mitochondrial reactive oxygen species (mROS), which initiate a signaling cascade to cause pathogenic necrosis of mycobacterium-infected macrophages. In zebrafish, we identified the mechanism of TNF-induced mROS in tuberculosis. Excess TNF in mycobacterium-infected macrophages elevates mROS production by reverse electron transport (RET) through complex I. TNF-activated cellular glutamine uptake leads to an increased concentration of succinate, a Krebs cycle intermediate. Oxidation of this elevated succinate by complex II drives RET, thereby generating the mROS superoxide at complex I. The complex I inhibitor metformin, a widely used antidiabetic drug, prevents TNF-induced mROS and necrosis of Mycobacterium tuberculosis-infected zebrafish and human macrophages; metformin may therefore be useful in tuberculosis therapy.

Metformin: Sex/Gender Differences in Its Uses and Effects—Narrative Review

Metformin (MTF) occupies a major and fundamental position in the therapeutic management of type 2 diabetes mellitus (T2DM). Gender differences in some effects and actions of MTF have been reported. Women are usually prescribed lower MTF doses compared to men and report more gastrointestinal side effects. The incidence of cardiovascular events in women on MTF has been found to be lower to that of men on MTF. Despite some promising results with MTF regarding pregnancy rates in women with PCOS, the management of gestational diabetes, cancer prevention or adjunctive cancer treatment and COVID-19, most robust meta-analyses have yet to confirm such beneficial effects.

Imeglimin: A New Promising and Effective Weapon in the Treatment of Type 2 Diabetes

Imeglimin is a novel molecule currently under development for the treatment of type 2 diabetes mellitus, and is the first agent of the 'glimin' class of glucose-lowering medication. It has a unique mechanism of action that targets the three main pathophysiologic components of type 2 diabetes: impaired glucose uptake by muscle tissue, excess hepatic gluconeogenesis and increased β-cell apoptosis. To date, imeglimin has been evaluated in many preclinical and clinical trials and has shown to have notable antihyperglycaemic effects, such as statistically significant reductions in glycated haemoglobin, fasting plasma glucose and other glycaemic parameters. The encouraging tolerability profile, combined with its efficacy, could make it suitable as a monotherapy or in combination with other classes of antidiabetic agents, hopefully in the near future.

A Comparative Study of the Lipophilicity of Metformin and Phenformin

The results presented in this paper confirm the beneficial role of an easy-to-use and low-cost thin-layer chromatography (TLC) technique for describing the retention behavior and the experimental lipophilicity parameter of two biguanide derivatives, metformin and phenformin, in both normal-phase (NP) and reversed-phase (RP) TLC systems. The retention parameters (R_F, R_M) obtained under different chromatographic conditions, i.e., various stationary and mobile phases in the NP-TLC and RP-TLC systems, were used to determine the lipophilicity parameter (R_MW) of metformin and phenformin. This study confirms the poor lipophilicity of both metformin and phenformin. It can be stated that the optimization of chromatographic conditions, i.e., the kind of stationary phase and the composition of mobile phase, was needed to obtain the reliable value of the chromatographic lipophilicity parameter (R_MW) in this study. The fewer differences in the R_MW values of both biguanide derivatives were ensured by the RP-TLC system composed of RP2, RP18, and RP18W plates and the mixture composed of methanol, propan-1-ol, and acetonitrile as an organic modifier compared to the NP-TLC analysis. The new calculation procedures for logP of drugs based on topological indices ⁰χ^ν, ⁰χ, ¹χ^ν, M, and M^ν may be a certain alternative to other algorithms as well as the TLC procedure performed under optimized chromatographic conditions. The knowledge of different lipophilicity parameters of the studied biguanides can be useful in the future design of novel and more therapeutically effective metformin and phenformin formulations for antidiabetic and possible anticancer treatment. Moreover, the topological indices presented in this work may be further used in the QSAR study of the examined biguanides.

Pathogenic mitochondrial dysfunction and metabolic abnormalities

Herein we trace links between biochemical pathways, pathogenesis, and metabolic diseases to set the stage for new therapeutic advances. Cellular and acellular microorganisms including bacteria and viruses are primary pathogenic drivers that cause disease. Missing from this statement are subcellular compartments, importantly mitochondria, which can be pathogenic by themselves, also serving as key metabolic disease intermediaries. The breakdown of food molecules provides chemical energy to power cellular processes, with mitochondria as powerhouses and ATP as the principal energy carrying molecule. Most animal cell ATP is produced by mitochondrial synthase; its central role in metabolism has been known for >80 years. Metabolic disorders involving many organ systems are prevalent in all age groups. Progressive pathogenic mitochondrial dysfunction is a hallmark of genetic mitochondrial diseases, the most common phenotypic expression of inherited metabolic disorders. Confluent genetic, metabolic, and mitochondrial axes surface in diabetes, heart failure, neurodegenerative disease, and even in the ongoing coronavirus pandemic.

Water-Soluble Gold(III)-Metformin Complex Alters Mitochondrial Bioenergetics in Breast Cancer Cells

Chemical control of mitochondrial dynamics and bioenergetics can unravel fundamental biological mechanisms and therapeutics for several diseases including, diabetes and cancer. We synthesized stable, water-soluble gold(III) complexes (Auraformin) supported by biguanide metformin or phenylmetformin for efficacious inhibition of mitochondrial respiration. The new compounds were characterized following the reaction of [C N]-cyclometalated gold(III) compounds with respective biguanides. Auraformin is solution stable in a physiologically relevant environment. We show that auraformin decreases mitochondrial respiration efficiently in comparison to the clinically used metformin by 100-fold. The compound displays significant mitochondrial uptake and induces antiproliferative activity in the micromolar range. Our results shed light on the development of new scaffolds as improved inhibitors of mitochondrial respiration.

Metformin hydrochloride entrapment in sorbitan monostearate for intestinal permeability enhancement and pharmacodynamics

Penetration enhancement of metformin hydrochloride via its molecular dispersion in sorbitan monostearate microparticles is reported. This represents basic philosophy to maximize its entrapment for maximum penetration effect. Drug dispersion in sorbitan monostearate with different theoretical drug contents (TDC) were prepared. Products showed excellent micromeritics and actual drug content (ADC) increased by increasing TDC. The partition coefficient of the drug products showed huge improvement. This indicates the drug entrapped in the polar part of sorbitan monostearate as a special image which effects on the drug release. The drug permeation profiles from the different products are overlapped with nearly equal permeation parameters. The permeation results suggested the main driving force for improving the drug paracellular pathway is its dispersion in sorbitan monostearate and is independent of ADC. Pharmacodynamic of the products showed a significant improvement than the drug alone at p ˂ 0.05. ANOVA test indicated the insignificant pharmacodynamic difference between the low, middle, and high ADC of the products. An excellent correlation founded between the drug permeation and pharmacodynamic precents. Drug permeation driving force via the paracellular pathway is its entrapment in sorbitan monostearate and independent on ADC. The technique is simple and the products had excellent micromeritics.

Novel approaches to pharmacological management of type 2 diabetes in Japan

INTRODUCTION

Newly developed anti-diabetic medications have had multiple activities, beyond a blood glucose-lowering effect. Current drugs for treating type 2 diabetes mellitus (T2DM) are based on the use of gastrointestinal hormones. Representative incretin preparations, such as those with glucagon-like peptide (GLP)-1 or gastric inhibitory polypeptide (GIP) activity, aim to provide new means of controlling blood glucose levels, body weight, and lipid metabolism.

AREA COVERED

In this manuscript, the pathophysiology of T2DM and the activities and characteristics of novel diabetic drugs are reviewed in the context of the Japanese population. This review also highlights the need for novel medicines to overcome the accompanying challenges. Finally, the author provides the reader with their expert perspectives.

EXPERT OPINION

The incidence of T2DM has been increasing in the aging of Japanese society. In older people, medical development should focus on safety, easier self-administration, and the relief of caregiver burden in terms of continuous administration. In the young, the focus should be on effectiveness, with a particular emphasis on the protection of organs, increasing the ease of adherence, and safety. Novel medicines will need to push the envelope in these areas.

Determination of sitagliptin in human plasma using a smart electrochemical sensor based on electroactive molecularly imprinted nanoparticles

Sitagliptin is a hypoglycaemic agent used to reduce blood sugar levels in patients with type 2 diabetes mellitus (T2DM). Real time monitoring of sitagliptin levels is crucial to prevent overdose, which might cause liver, kidney and pancreatic diseases. As an alternative solution, a sitagliptin voltammetric sensor was fabricated using artificial receptors called electroactive molecularly imprinted polymer nanoparticles (nanoMIPs). The nanoMIP tagged with a redox probe (ferrocene) combines both the recognition and reporting functions. Traditional electrochemical sensors determine the redox activity of an analyte. Thus, they are influenced by interfering molecules and the nature of the sample. These innovative nanoMIPs allow us to easily design and customise sensors, increase their sensitivity and minimise the cross reactivity in biological samples. The present technology replaces the traditional enzyme-mediator pairs used in traditional biosensors. The polymer composition was optimized "in silico" using docking and screening methods. Nanoparticles were synthesized via free radical polymerization and a solid phase method and then characterized by infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The specific sitagliptin nanoparticles were covalently immobilized on platinum electrodes via silane and carbodiimide chemistry. The determination of sitagliptin in human plasma by a nanoMIP sensor was assessed by differential pulse voltammetry (DPV). The sensor current response was directly related to the change in nanoMIP conformation triggered by the analyte. The optimisation of the sensor response was made by adjusting (i) the silane concentration, (ii) nanoMIP concentration, and (iii) immobilization time. The sensor measurements in plasma revealed high selectivity and a sensitivity of 32.5 ± 0.6 nA pM-1 towards sitagliptin, and the limit of detection of the fabricated sensor was found to be 0.06 pM. The sensor displayed a satisfactory performance for the determination of sitagliptin in spiked human plasma, demonstrating the potential of this technology for drug monitoring and clinical diagnosis.

The effects of metformin treatment on the ovaries and uterus of offspring

OBJECTIVE

The aim of this study is to investigate the effects of metformin treatment at different dosage levels on the ovaries and uteruses of rat offspring in the course of the intrauterine period.

METHODS

 Saline, metformin (100 mg/kg/day), and metformin (200 mg/kg/day) were administered via oral gavage between the 6th and 15th days of gestation to the 9 pregnant rats (n = 3/group). After birth, 5 female offspring were separated from each group and perfused on the 60th day of postnatal development. The cortex and medulla volumes of the ovaries, the thicknesses of epithelium and endometrium of the uteruses and the total oocyte number density were estimated. In addition, the estradiol levels in blood samples were measured by the ELISA method.

RESULTS

There were no statistically significant differences among the groups regarding the number of oocytes, the volumes of ovarian cortex, medulla, primary and secondary follicles (p > .05). In comparison with the control group, the volume of the tertiary follicle, the thickness of the uterus epithelium, and the estradiol level were significantly decreased in Metformin 200 group (p < .05).

CONCLUSIONS

The gestational exposure to high dose metformin may result in decreased estradiol production and subsequently decreased endometrial thickness of offspring rats.

Roles of interstitial fluid pH and weak organic acids in development and amelioration of insulin resistance

Type 2 diabetes mellitus (T2DM) is one of the most common lifestyle-related diseases (metabolic disorders) due to hyperphagia and/or hypokinesia. Hyperglycemia is the most well-known symptom occurring in T2DM patients. Insulin resistance is also one of the most important symptoms, however, it is still unclear how insulin resistance develops in T2DM. Detailed understanding of the pathogenesis primarily causing insulin resistance is essential for developing new therapies for T2DM. Insulin receptors are located at the plasma membrane of the insulin-targeted cells such as myocytes, adipocytes, etc., and insulin binds to the extracellular site of its receptor facing the interstitial fluid. Thus, changes in interstitial fluid microenvironments, specially pH, affect the insulin-binding affinity to its receptor. The most well-known clinical condition regarding pH is systemic acidosis (arterial blood pH < 7.35) frequently observed in severe T2DM associated with insulin resistance. Because the insulin-binding site of its receptor faces the interstitial fluid, we should recognize the interstitial fluid pH value, one of the most important factors influencing the insulin-binding affinity. It is notable that the interstitial fluid pH is unstable compared with the arterial blood pH even under conditions that the arterial blood pH stays within the normal range, 7.35-7.45. This review article introduces molecular mechanisms on unstable interstitial fluid pH value influencing the insulin action via changes in insulin-binding affinity and ameliorating actions of weak organic acids on insulin resistance via their characteristics as bases after absorption into the body even with sour taste at the tongue.

Critical Analysis of Drug Product Recalls due to Nitrosamine Impurities

A product recall is the outcome of a careful pharmacovigilance; and it is an integral part of drug regulation. Among various reasons for product recall, the detection of unacceptable levels of carcinogenic impurities is one of the most serious concerns. The genotoxic and carcinogenic potential of N-nitrosamines raises a serious safety concern, and in September 2020, the FDA issued guidance for the pharmaceutical industry regarding the control of nitrosamines in drug products. The FDA database shows that >1400 product lots have been recalled from the market due to the presence of carcinogenic N-nitrosamine impurities at levels beyond the acceptable intake limit of 26.5 ng/day. The drugs that were present in recalled products include valsartan, irbesartan, losartan, metformin, ranitidine, and nizatidine. This perspective provides a critical account of these product recalls with an emphasis on the source and mechanism for the formation of N-nitrosamines in these products.

Antidiabetic compounds 8a, 8b, 8k, and 9h enhance insulin secretion: activity and mechanism

PURPOSE

This study primarily investigated the effects of hypoglycemic compounds (Imeglimin derivatives) on insulin secretion in type 2 diabetes mellitus (T2DM), and further explored the possible mechanism underlying these effects.

METHODS

Firstly, Metformin was used as the initiating compound to synthesize three sets of derivatives which contained Imeglimin structure core. At the cellular level, we screened compounds with better effect on the activity of insulin receptor tyrosine protein kinase (IFcTPK) after the islet β cells were treated with the compounds of different concentrations. The insulin secretion was assessed using radioimmunoassay and the cytotoxicity to islet β cells was evaluated by means of MTT assay following treatment with the compounds. The Ca²⁺-related mechanism by which these compounds promote insulin secretion was elucidated with whole cell recordings from current-clamp mode.

RESULTS

Totally, 48 synthesized compounds were generated, wherein 10 compounds could increase the activity of IFcTPK in HIT-T15 cells better among these compounds. The modified Imeglimin, especially in the structure of hydrophilic hydroxyl or piperidine rings, could improve the activity of the compound to promote insulin secretion. Furthermore, the compounds 8a, 8b, 8k, and 9h revealed high insulin secretion-promoting activity. These compounds enhanced insulin secretion in islet β cells by repressing the ATP-sensitive K(+) and voltage-gated K+ pathway.

CONCLUSIONS

Our findings indicate that the hypoglycemic compounds 8a, 8b, 8k, and 9h confer better promotive effect on insulin secretion, which provides a reference for the development of drugs with better hypoglycemic activity.

Pathological and Pharmacological Roles of Mitochondrial Reactive Oxygen Species in Malignant Neoplasms: Therapies Involving Chemical Compounds, Natural Products, and Photosensitizers

Oxidative stress plays an important role in cellular processes. Consequently, oxidative stress also affects etiology, progression, and response to therapeutics in various pathological conditions including malignant tumors. Oxidative stress and associated outcomes are often brought about by excessive generation of reactive oxygen species (ROS). Accumulation of ROS occurs due to dysregulation of homeostasis in an otherwise strictly controlled physiological condition. In fact, intracellular ROS levels are closely associated with the pathological status and outcome of numerous diseases. Notably, mitochondria are recognized as the critical regulator and primary source of ROS. Damage to mitochondria increases mitochondrial ROS (mROS) production, which leads to an increased level of total intracellular ROS. However, intracellular ROS level may not always reflect mROS levels, as ROS is not only produced by mitochondria but also by other organelles such as endoplasmic reticulum and peroxisomes. Thus, an evaluation of mROS would help us to recognize the biological and pathological characteristics and predictive markers of malignant tumors and develop efficient treatment strategies. In this review, we describe the pathological significance of mROS in malignant neoplasms. In particular, we show the association of mROS-related signaling in the molecular mechanisms of chemically synthesized and natural chemotherapeutic agents and photodynamic therapy.

The Acidic Microenvironment: Is It a Phenotype of All Cancers? A Focus on Multiple Myeloma and Some Analogies with Diabetes Mellitus

Multiple myeloma (MM) is a hematological malignancy with a poor prognosis while with a long and progressive outcome. To date, the therapeutic options are restricted to few drugs, including thalidomide or its derivates and autologous transplantation including stem-cell transplantation. More recently, the use of both proteasome inhibitors and monoclonal antibodies have been included in MM therapy, but the clinical results are still under evaluation. Unfortunately, death rates (within the 5-year overall survival rates) are still very high (45%), with no relevant improvement over the past 10 years. Here, we discuss data supporting a new therapeutic approach against MM, based on a common phenotype of tumor malignancies, which is the acidic microenvironment. Extracellular acidity drastically reduces the efficacy of both anti-tumor drugs and the immune reaction against tumors. Pre-clinical data have shown that anti-acidic drugs, such as proton pump inhibitors (PPIs), have a potent cytotoxic effect against human MM cells, thus supporting their use in the treatment of this malignancy. Here, we discuss also similarities between MM and type II diabetes mellitus (DM) with high risk of developing MM, suggesting that both anti-diabetic drugs and a hypocaloric diet may help in curing MM patients.

Comparison of Effects of Metformin, Phenformin, and Inhibitors of Mitochondrial Complex I on Mitochondrial Permeability Transition and Ischemic Brain Injury

Damage to cerebral mitochondria, particularly opening of mitochondrial permeability transition pore (MPTP), is a key mechanism of ischemic brain injury, therefore, modulation of MPTP may be a potential target for a neuroprotective strategy in ischemic brain pathologies. The aim of this study was to investigate whether biguanides-metformin and phenformin as well as other inhibitors of Complex I of the mitochondrial electron transfer system may protect against ischemia-induced cell death in brain slice cultures by suppressing MPTP, and whether the effects of these inhibitors depend on the age of animals. Experiments were performed on brain slice cultures prepared from 5-7-day (premature) and 2-3-month old (adult) rat brains. In premature brain slice cultures, simulated ischemia (hypoxia plus deoxyglucose) induced necrosis whereas in adult rat brain slice cultures necrosis was induced by hypoxia alone and was suppressed by deoxyglucose. Phenformin prevented necrosis induced by simulated ischemia in premature and hypoxia-induced-in adult brain slices, whereas metformin was protective in adult brain slices cultures. In premature brain slices, necrosis was also prevented by Complex I inhibitors rotenone and amobarbital and by MPTP inhibitor cyclosporine A. The latter two inhibitors were protective in adult brain slices as well. Short-term exposure of cultured neurons to phenformin, metformin and rotenone prevented ionomycin-induced MPTP opening in intact cells. The data suggest that, depending on the age, phenformin and metformin may protect the brain against ischemic damage possibly by suppressing MPTP via inhibition of mitochondrial Complex I.