Lo clásico y lo nuevo en el tratamiento del sobrepeso y la obesidad / The classic and the new in the treatment of overweight and obesity

Así como planteamos en la primera entrega de esta serie de artículos de actualización sobre la obesidad, resulta urgente revisar el abordaje tradicional que la comunidad médica le ofrece a las personas con cuerpos gordos. En este segundo artículo desarrollaremos en profundidad diferentes alternativas terapéuticas para los pacientes que desean bajar de peso:plan alimentario, actividad física, tratamiento farmacológico y cirugía metabólica. (AU)

As we proposed in the first issue of this series of articles, it is urgent to review the traditional approach that the medical community offers to people with fat bodies. This second article will develop different therapeutic alternatives for patients who want to lose weight: eating plans, physical activity, pharmacological treatment, and metabolic surgery. (AU)

La semaglutida en el tratamiento de las personas con diabesidad / Semaglutide in the Treatment of Diabesity Individuals

Introducción: La semaglutida es un fármaco que contribuye a la liberación de insulina por el páncreas y a la supresión del apetito por lo que lo convierte en un importante candidato para ser usado en el tratamiento de la diabesidad. Objetivo: Describir el efecto de la semaglutida en el tratamiento de las personas con diabesidad. Métodos: Se revisó la literatura publicada en el período comprendido de enero-febrero de 2021. Las palabras clave utilizadas fueron obesidad; diabetes mellitus; diabesidad; semaglutida; análogo del péptido similar al glucagón tipo 1. Se utilizaron como motores de búsqueda las bases de datos de Google Académico, PubMed y SciELO. Se evaluaron diferentes trabajos de revisión, investigación y páginas web que tenían menos de 10 años de publicados en idioma español, portugués o inglés, y que por el título trataban el tema de estudio. Fueron excluidos los artículos que no abordaron la relación entre diabetes y obesidad, así como el tratamiento con análogos del péptido similar al glucagón tipo 1. Esto permitió la consulta de 84 artículos, de los cuales 59 fueron referenciados. Conclusiones: El empleo de semaglutida favorece una mejor evolución en paciente con diabesidad, como complemento de una dieta y una actividad física adecuada. Al optimizar el control glucémico, contribuir a la pérdida de peso y a la mejoraría de ciertas comorbilidades, entre ellas la salud cardiovascular(AU)

Introduction: Semaglutide is a drug that contributes to the release of insulin from the pancreas and suppresses appetite, which makes it an important candidate for treating diabesity. Objective: To describe the role of semaglutide in the treatment of diabesity individuals. Methods: The necessary information to write this article was obtained in the 2022 two-month period January-February. The keywords used were obesity; Mellitus diabetes; diabesity; semaglutide; type 1 glucagon-like peptide analogue. The search engines corresponding to the Google Scholar, PubMed and SciElO databases were used. Different review, research and web pages were evaluated, which in general were published no more than 10 years ago, in Spanish, Portuguese or English and which dealt with the subject of study by title. Articles that did not address the relationship between diabetes and obesity, as well as treatment with glucagon-like peptide 1 analogues, were excluded. This allowed the consultation of 84 articles, 59 of them were referenced. Conclusions: The use of semaglutide, as a complement to a diet and physical activity appropriate to the needs of patients with diabesity, brought about several effects that favor better evolution of this health problem, by optimizing glycemic control, contributing to the loss of weight and the improvement of certain comorbidities, including cardiovascular health(AU)

Efecto de la dieta CAF sobre la capacidad de EX4 de modular la expresión de marcadores proteicos de oxidación de ácidos grasos y termogénesis en músculo de ratones / Effect of the CAF diet on the ability of EX4 to modulate the expression of protein markers of fatty acid oxidation and thermogenesis in mouse muscle

El ambiente obesogénico promueve la obesidad al facilitar el acceso y consumo de una amplia variedad de alimentos palatables altos en calorías. La activación del receptor de GLP1 (GLP1R) reduce la ingesta de alimentos, enlentece el vaciamiento gástrico y promueve un balance energético negativo a través de su acción en distintos órganos como el músculo esquelético, disminuyendo así el peso corporal. La obesidad inducida por dieta alta en grasa disminuye el efecto anorexigénico de la administración sistémica vía intra-peritoneal de EX4 (agonista de GLP1R). Sin embargo, se desconoce si la exposición a un ambiente obesogénico previo a la manifestación de obesidad disminuye los efectos anorexigénicos de EX4 o un posible efecto de EX4 sobre marcadores de oxidación de ácidos grasos y termogénesis en músculo esquelético. El objetivo de esta investigación fue determinar el efecto a corto plazo de la dieta CAF, un modelo del ambiente obesogénico humano, sobre la capacidad de EX4 de reducir la ingesta y modular la expresión de marcadores proteicos de oxidación de ácidos grasos y termogénesis (CPT1 y UCP2) en músculo de ratones. Nuestros datos muestran que una inyección intraperitoneal de EX4 a ratones C57BL/6J alimentados con dieta CAF o dieta control durante 10 días no altera la ingesta calórica total, peso corporal, o la expresión de proteínas marcadoras de los procesos de beta-oxidación y de termogénesis (CPT1 y UCP2). Estos datos sugieren que protocolos alternativos de administración de EX4 son necesarios para observar los efectos fisiológicos de la activación de GLP1R.

The obesogenic environment promotes obesity by facilitating access to and consumption of a wide variety of palatable, high-calorie foods. Activation of the GLP1 receptor (GLP1R) reduces food intake, slows gastric emptying, and promotes a negative energy balance by acting on organs such as skeletal muscle, thus decreasing body weight. Obesity induced by a high-fat diet decreased the anorexigenic effect of intraperitoneal systemic administration of EX4 (GLP1R agonist). However, it is unknown whether exposure to an obesogenic environment before the manifestation of obesity diminishes the anorexigenic effects of EX4 or a possible effect of EX4 on markers of fatty acid oxidation and thermogenesis in skeletal muscle. This investigation aimed to determine the short-term effect of the CAF diet, a model of the human obesogenic environment, on the ability of EX4 to reduce intake and modulate the expression of protein markers of fatty acid oxidation and thermogenesis (CPT1 and UCP2) in mouse muscle. Our data show that intraperitoneal injection of EX4 to C57BL/6J mice fed CAF diet or control diet for ten days does not alter total caloric intake, body weight, or expression of proteins markers of beta-oxidation and thermogenesis processes (CPT1 and UCP2). These data suggest that alternative EX4 administration protocols are necessary to observe the physiological effects of GLP1R activation.

New practice in semaglutide on type-2 diabetes and obesity: clinical evidence and expectation / 医学前沿

Obesity is an important risk factor of type 2 diabetes (T2D), which has become an important factor threatening human health. However, no perfect drug choice for obesity exists. Semaglutide is a kind of human glucagon-like peptide-1 (GLP-1) analog that promotes insulin secretion while inhibiting glucagon secretion through a glucose concentration-dependent mechanism. GLP-1 can also delay stomach emptying and suppress appetite to help lose weight. This review summarizes clinical evidence of the semaglutide effect on T2D and obesity and establishes expectations on future clinical trials for obesity treatment.

Making a case for the combined use of SGLT2 inhibitors and GLP1 receptor agonists for cardiorenal protection / Argumentando a favor do uso combinado de inibidores de SGLT2 e agonistas do receptor GLP1 para proteção cardiorrenal

ABSTRACT Sodium glucose cotransporter-2 (SGLT2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1RA) were initially approved to improve glycemic control in the treatment of type 2 diabetes. Clinical trials have also demonstrated beneficial effects with regards to cardiovascular and renal parameters. Beyond improving glycemic control, these therapies promote weight loss and lower blood pressure when used individually, and in an additive manner when used together. Accordingly, taking advantage of complementary mechanisms of action with the combined use of these two classes of agents to further improve cardiorenal outcomes is conceptually appealing, but has yet to be explored in detail in clinical trials. In this review, we discuss proposed mechanisms for renal protection, clinical benefits, and adverse events associated with the individual and combined use of SGLT2 inhibitors and GLP-1RA. The management of type 2 diabetes has significantly changed over the last few years, moving away from solely glycemic control towards the concurrent management of associated comorbidities in a patient population at significant risk of cardiovascular disease and progression of chronic kidney disease. It is from this perspective that we seek to outline the rationale for the sequential and/or combined use of SGLT2 inhibitors and GLP-1RA in patients with type 2 diabetes.

RESUMO Inibidores do cotransporter-2 de glicose sódica (SGLT2) e agonistas do receptor peptídeo-1 do tipo glucagon (GLP-1RA) foram inicialmente aprovados para melhorar o controle glicêmico no tratamento da diabetes tipo 2. Os ensaios clínicos também demonstraram efeitos benéficos em relação aos parâmetros cardiovasculares e renais. Além de melhorar o controle glicêmico, essas terapias promovem perda de peso e redução da pressão arterial quando usadas individualmente, e de forma aditiva quando usadas em conjunto. Consequentemente, tirar proveito de mecanismos de ação complementares com o uso combinado dessas duas classes de agentes para melhorar ainda mais os resultados cardiorrenais é conceitualmente atraente, mas ainda precisa ser explorado em detalhes em ensaios clínicos. Nesta revisão, discutimos os mecanismos propostos para proteção renal, benefícios clínicos e eventos adversos associados ao uso individual e combinado de inibidores de SGLT2 e GLP-1RA. O tratamento do diabetes tipo 2 mudou significativamente nos últimos anos, passando do controle exclusivamente glicêmico para o tratamento simultâneo de comorbidades associadas em uma população de pacientes com risco significativo de doença cardiovascular e progressão da doença renal crônica. É nessa perspectiva que procuramos delinear a justificativa para o uso sequencial e/ou combinado de inibidores de SGLT2 e GLP-1RA em pacientes com diabetes tipo 2.

A Review of the Effects of Glucagon-Like Peptide-1 Receptor Agonists and Sodium-Glucose Cotransporter 2 Inhibitors on Lean Body Mass in Humans

Weight loss is an important goal in the management of several chronic conditions, including type 2 diabetes mellitus, and pharmacological therapies that aid weight loss are appealing. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter 2 inhibitors (SGLT2is) are novel glucose-lowering therapies that have been shown to induce clinically significant reductions in body weight. However, this weight loss may not be attributed solely to fat mass (FM). Given the importance of skeletal muscle and lean body mass (LBM) on cardio-metabolic health and physical function, we reviewed the available literature reporting the effects of GLP-1RAs and SGLT2is on body composition. Results demonstrate that, in most circumstances, the weight loss associated with both therapies predominantly comprises a reduction in FM, although significant heterogeneity exists between studies. In over half of the studies identified, the proportion of LBM reduction ranged between 20% and 50% of total weight lost, which is consistent with diet-induced weight loss and bariatric surgery. No clear differences existed between GLP-1RAs and SGLT2is. Consequently, the loss of LBM and skeletal muscle associated with weight loss induced by GLP-1RAs and SGLT2is warrants attention. Strategies to preserve skeletal muscle and improve physical function, for example through structured exercise, are of great importance.

Comparative study on anorexigenic effect of glucagon-like peptide-1 receptor agonists in rats / 生理学报

Glucagon-like peptide-1 (GLP-1) expression is shared by both intestinal cells and neurons of brainstem, which plays anorexigenic role on food intake. However, the exact source of physiological GLP-1 influencing food intake and pertinent mechanism of GLP-1 receptor agonists (GLP-1RA) remain unelucidated. In this study, the immediate early gene product c-Fos was chosen as the specific antigen for immunohistochemistry to show the certain areas of central nervous system (CNS) activation by the GLP-1RA. Thirty normal SD rats were randomly assigned to 3 groups, which were single intraperitoneally injected with Liraglutide (200 μg/kg), Exenatide (10 μg/kg) and saline, respectively. After injection, the amount of food intake and acute glycemic variation were assessed for comparison. The results showed that acute pharmacological dosage of GLP-1RA (Liraglutide or Exenatide) could significantly influence food intake. However, glycemic change indicated that the anorexic effect was dissociated with change in blood glucose in normal rats. Moreover, c-Fos was expressed significantly higher in major critical nuclei related to food intake in GLP-1RA groups when compared with the control group, and its expression was also found in spinal cord. The results suggested that acute administration of pharmacological doses of GLP-1 influences CNS via circulation and vagal pathways, especially on the arcuate nucleus (ARC) and the nucleus of solitary tract (NTS), and GLP-1 modulates autonomic nervous activities.

Effects of Exendin-4 on the differentiation of neural stem cells from subventricular zone of adult mice in vitro / 中国应用生理学杂志

OBJECTIVE@#To study the effect of exendin-4(Ex-4) on the differentiation of neural stem cells(NSCs) in adult mouse subventricular zone(SVZ)and its mechanism .@*METHODS@#NSCs in the SVZ were derived from 5-week C57BL/6J mice and the expression of nestin was detected by immunofluorescence. The cell morphology was observed after the cells treatmed with 100 nmol/L Ex-4 for 14 days.The expressions of nestin and glucagon-like peptide-1 receptor (GLP-1R) were detected by immunofluorescence. GLP-1R was knocked down by using shRNA and the study was divided into four groups: control group, Ex-4 group, GLP-1R knockdown group, GLP-1R knockdown + Ex-4 group. After treatment with 100 nmol/L Ex-4 for 14 d, β-tublin III and glial fibrillary acidic protein (GFAP) were labeled by immunofluorescence and then the proportion of β-tublin III positive cells were counted. Western blot was used to detect the activation of cAMP-response element binding protein (CREB) in NSCs. In order to further study the effects of Ex-4 on mitogen-activated protein kinase(MAPK) and phosphatidylinositol 3-hydroxy kinase (PI3K) pathways, the cells were pretreated with MAPK inhibitor U0126 at a concentration of 0.07 μmol/L for 30 min or PI3K inhibitor LY294002 at 50 μmol for 2 h, respectively. The study was divided into six groups: control group, Ex-4 group, U0126 group, U0126 + Ex-4 group, LY294002 group, LY294002 + Ex-4 group. The activation of CREB in each group was detected by Western blot. The experiment was repeated three times independently.@*RESULTS@#NSCs were successfully extracted from SVZ of C57BL/6J mice. Immunofluorescence showed that nestin and GLP-1R were positive in NSCs. Compared with the control group, the proportion of neurons differentiated from Ex-4 group was higher. The percentage of neurons in GLP-1R knockdown + Ex-4 group was basically the same as that in control group (P＜0.01). The positive cells of beta-tublin III showed positive activation of GLP-1R and CREB. Western blot showed that CREB was significantly activated in the Ex-4 group, and knockdown of GLP-1R abolished its activation (P＜0.01). U0126 did not affect Ex-4-mediated CERB activation, and LY294002 significantly reduced Ex-4-mediated CREB activation (P＜0.01).@*CONCLUSION@#Ex-4 promotes the differentiation of NSCs into neurons in SVZ of adult mice through GLP-1R receptor, which may be achieved through PI3K/CREB pathway.

Understanding the Mechanism of Action and Clinical Implications of Anti-Obesity Drugs Recently Approved in Korea / 가정의학회지

The Korean Ministry of Food and Drug Safety has approved three anti-obesity drugs for long-term management in the past decade. In addition, since 2019, bariatric surgery has been financially supported by National Health Insurance Service in Korea. In this review, the mechanisms of action and the clinical implications of the recently approved anti-obesity drugs, lorcaserin, naltrexone/bupropion, and liraglutide are explained. Lorcaserin stimulates proopiomelanocortin (POMC)/cocaine- and amphetamine-regulated transcript (CART) neurons and inhibits neuropeptide Y (NPY)/agouti-related peptide (AgRP) neurons, which results in the activation of melanocortin 3/4 receptors. Naltrexone/bupropion stimulates POMC neurons through bupropion; this stimulation is augmented by blocking the autoinhibitory mechanism of POMC with naltrexone. The hypophagic effect of liraglutide is mediated through the direct activation of POMC/CART neurons and the indirect suppression of NPY/AgRP neurons through γ-aminobutyric acid-dependent signaling, with adjunctive suppression of the mesolimbic dopamine reward system. In addition to liraglutide, another glucagon-like peptide-1 receptor agonist, semaglutide, is expected to be added to the list of anti-obesity drugs in the near future. In patients with obesity and high cardiovascular risk, lorcaserin was considered neutral and liraglutide was considered favorable, whereas inconclusive results were obtained for naltrexone/bupropion.

Effect of glucagon-like peptide 1 receptor agonists on body fat redistribution and muscle mass in overweight and obese type 2 diabetic patients / 南方医科大学学报

OBJECTIVE@#To investigate the effect of glucagon-like peptide 1 receptor agonists (GLP-1RAs) on body fat redistribution and muscle mass in overweight/obese patients with type 2 diabetes (T2DM).@*METHODS@#We retrospectively analyzed the data of 76 patients with body mass indexes (BMI)≥24 kg/m, who had an established diagnosis of T2DM in our department between December, 2014 and September, 2015. We divided these patients according to their BMI in overweight group (BMI of 24-27.9 kg/m, =14), obese group (BMI of 28-31.9 kg/m, =35) and severely obese group (BMI≥32 kg/m, =27). All the patients received treatment with GLP-1RAs (Exenatide or Liraglutide) for 3.0 to 29.0 weeks (mean 8.9 weeks), and their blood glucose, HbA1c and serum lipids were analyzed. For each patient, the fat and muscle masses were analyzed using a human body composition analyzer (JAWON-IOI353, Korea) before and after GLP-1RAs treatment.@*RESULTS@#Treatment with GLP-1RAs significantly decreased BMI and visceral adiposity index (VAI) in all the patients in the 3 groups ( < 0.05). The treatment significantly decreased the body weight in the overweight group and obese group by 2.70 kg (0.60-4.95 kg) and 2.65 kg (1.45-6.40 kg), respectively ( < 0.05), and significantly decreased the waist-to-hip ratio (WHR) in the overweight group ( < 0.05). The obese and severely obese patients showed significantly decreased percentage body fat (including both subcutaneous and visceral fat) and increased muscle mass after the treatment ( < 0.05). Compared with those in the overweight group, the percentage body fat and VAI were significantly decreased in the obese group after the treatment ( < 0.05), and the percentage of subcutaneous fat reduced and the muscle ratio increased more obviously in the obese and severely obese patients ( < 0.05).@*CONCLUSIONS@#GLP-1RAs treatment can significantly lower BMI and improve body fat distribution in obese patients with T2DM, especially in patients with a greater BMI.

Safety Issues with Sodium-Glucose Cotransporter 2 Inhibitors: Clinical Considerations / 임상당뇨병

Diabetes mellitus (DM) is linked to poor outcomes after cardiovascular events and renal complications. Recently, novel antidiabetic agents, such as dipeptidyl peptidase-4 inhibitors, sodium-glucose cotransporter 2 (SGLT2) inhibitors, and glucagon-like peptide-1 receptor agonists, are available. Among them, studies on SGLT2 inhibitors show favorable results both for cardiovascular and renal outcomes. SGLT2 inhibitors are well-tolerated with few side effects. Urinary tract infection has not been increased in many studies of SGLT2 inhibitors. The most frequent side-effect associated with SGLT2 inhibitors is mycotic infections in the genital area. Fortunately, these are generally mild in severity and easily treated with antibiotics. Hypoglycemia can occur when an SGLT2 inhibitor is added to sulfonylureas or insulin. Volume depletion and hypotension can be minimized by adjusting diuretics or other antihypertensive agents. Of note, acute kidney injury was observed in a few studies with SGLT2 inhibitors. However, in more recent observational studies, acute kidney injury was less frequently observed in conjunction with SGLT2 inhibitor treatment. An increased incidence of lower extremity amputation and fractures was observed in a large study with canagliflozin but not with other SGLT2 inhibitors. In conclusion, it is critical to understand the benefits and risks associated with use of SGLT2 inhibitors.

Injectable Therapy for Diabetes Mellitus: Glucagon-Like Peptide-1 Receptor Agonist / 임상당뇨병

According to the American Diabetes Association (ADA) and the European Association for the Study of Diabetes guideline for treatment of diabetes, glucagon-like peptide-1 receptor agonist (GLP-1 RA) is recommended in diabetic patients with established atherosclerotic cardiovascular disease. This recommendation is based on the results of recent cardiovascular outcome trials of this kind of medications. GLP-1 RAs have a glucose lowering effect with weight loss and a lower incidence of hypoglycemia, and can improve cardiovascular outcomes such as three-point major cardiovascular events composed of death from cardiovascular causes, non-fatal myocardial infarction, and non-fatal stroke. Also, several GLP-1 RAs have beneficial effects on renal outcomes, mainly due to improvement in macroalbuminuria. In addition, high-dose liraglutide (3 mg/day subcutaneous injection) showed efficacy for reducing body weight. Therefore GLP-1 RA may be effective in patients with established cardiovascular disease, chronic kidney disease, and/or metabolic syndrome.

Management of Hyperglycemia in Type 2 Diabetes: A Summary of New Consensus Report from the American Diabetes Association and the European Association for the Study of Diabetes in 2018 / 임상당뇨병

In 2018, the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD) published a consensus recommendation on management of hyperglycemia. This consensus report emphasized the need for patient-centered management considering multimorbidity and individual patient preferences and barriers. Patients with type 2 diabetes with established atherosclerotic cardiovascular disease who fail to control blood glucose with the initial glucose-lowering medication are recommended a sodium-glucose cotransporter 2 (SGLT2) inhibitor or a glucagon-like peptide 1 (GLP-1) receptor agonist. For patients with chronic kidney disease and heart failure, SGLT2 inhibitors are recommended. In patients who need an injectable medication, GLP-1 receptor agonists are the preferred choice over insulin. In this section, we summarize “Management of Hyperglycemia in Type 2 Diabetes, 2018. A Consensus Report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD).”

Glucagon-Like Peptide-1 Receptor Agonists for the Treatment of Type 2 Diabetes Mellitus: A Position Statement of the Korean Diabetes Association / 임상당뇨병

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) were recommended as a monotherapy or combination therapy with oral hypoglycemic agents or basal insulin in the position statement of the Korean Diabetes Association 2017 for pharmacological therapy, which was a change from the previous guideline that recommended them only as a combination therapy. Many randomized clinical trials and systematic reviews report that GLP-1RAs have considerable glucose-lowering effect and lead to weight reduction and low risk of hypoglycemia when used as a monotherapy or combination therapy. The results of cardiovascular outcome trials of long-acting GLP-1RAs (liraglutide, semaglutide) have demonstrated cardiovascular benefits in subjects with type 2 diabetes mellitus and a high risk of cardiovascular disease. The GLP-1RAs may be a choice of therapy when weight control and avoidance of hypoglycemia are important, and patients with high risk of cardiovascular disease might also favor choosing GLP-1RA.

Paradigm Changes in Diabetes Management Guidelines: American Diabetes Association 2018 / 임상당뇨병

The management of type 2 diabetes mellitus should comprise healthy lifestyle modifications along with tailored pharmacologic treatment. Traditionally, the American Diabetes Association (ADA)'s Diabetes Management Guidelines have not prioritized specific anti-diabetic drugs over others with regard to cardiovascular disease (CVD) and mortality prevention. Recently, two novel anti-diabetic medications proved to be significantly protective against future CVD and mortality, regardless of the glycemic levels achieved in type 2 diabetic patients with pre-existing CVD. The 2018 ADA Guidelines recommend SGLT2 inhibitor and/or GLP-1 receptor agonist be used for type 2 diabetes patients with atherosclerotic CVD after metformin monotherapy failure. Considering the value of CVD protection in the management of diabetes mellitus, this minor guideline adjustment could have far-reaching implications.

Potentiation of endothelium-dependent vasorelaxation of mesenteric arteries from spontaneously hypertensive rats by gemigliptin, a dipeptidyl peptidase-4 inhibitor class of anti-diabetic drug

Dipeptidyl peptidase4 (DPP4) inhibitors such as gemigliptin are anti-diabetic drugs elevating plasma concentration of incretins such as GLP-1. In addition to the DPP4 inhibition, gemigliptin might directly improve the functions of vessels under pathological conditions. To test this hypothesis, we investigated whether the acetylcholine-induced endothelium dependent relaxation (ACh-EDR) of mesenteric arteries (MA) are altered by gemigliptin pretreatment in Spontaneous Hypertensive Rats (SHR) and in Wistar-Kyoto rats (WKY) under hyperglycemia-like conditions (HG; 2 hr incubation with 50 mM glucose). ACh-EDR of WKY was reduced by the HG condition, which was significantly recovered by 1 µM gemigliptin while not by saxagliptin and sitagliptin up to 10 µM. The ACh-EDR of SHR MA was also improved by 1 µM gemigliptin while similar recovery was observed with higher concentration (10 µM) of saxagliptin and sitagliptin. The facilitation of ACh-EDR by gemigliptin in SHR was not observed under pretreatment with NOS inhibitor, L-NAME. In the endotheliumdenuded MA of SHR, sodium nitroprusside induced dose-dependent relaxation was not affected by gemigliptin. The ACh-EDR in WKY was decreased by treatment with 30 µM pyrogallol, a superoxide generator, which was not prevented by gemigliptin. Exendin-4, a GLP-1 analogue, could not enhance the ACh-EDR in SHR MA. The present results of ex vivo study suggest that gemigliptin enhances the NOS-mediated EDR of the HG-treated MA as well as the MA from SHR via GLP-1 receptor independent mechanism.

Glucagon-like peptide-1 and glucagon-like peptide-1 receptor agonists in the treatment of type 2 diabetes

The prevalence of type 2 diabetes (T2D) is increasing worldwide. Patients with T2D suffer from various diabetes-related complications. Since there are many patients with T2D that cannot be controlled by previously developed drugs, it has been necessary to develop new drugs, one of which is a glucagon-like peptide-1 (GLP-1) based therapy. GLP-1 has been shown to ameliorate diabetes-related conditions by augmenting pancreatic β-cell insulin secretion and having the low risk of causing hypoglycemia. Because of a very short half-life of GLP-1, many researches have been focused on the development of GLP-1 receptor (GLP-1R) agonists with long half-lives such as exenatide and dulaglutide. Now GLP-1R agonists have a variety of dosing-cycle forms to meet the needs of various patients. In this article, we review the physiological features of GLP-1, the effects of GLP-1 on T2D, the features of several GLP-1R agonists, and the therapeutic effect on T2D.

New Potential Targets of Glucagon-Like Peptide 1 Receptor Agonists in Pancreatic β-Cells and Hepatocytes

It is well known that both insulin resistance and decreased insulin secretory capacity are important factors in the pathogenesis of type 2 diabetes mellitus (T2DM). In addition to genetic factors, obesity and lipotoxicity can increase the risk of T2DM. Glucagon-like peptide 1 (GLP-1) receptor agonists are novel antidiabetic drugs with multiple effects. They can stimulate glucose-dependent insulin secretion, inhibit postprandial glucagon release, delay gastric emptying, and induce pancreatic β-cell proliferation. They can also reduce the weight of patients with T2DM and relieve lipotoxicity at the cellular level. Many intracellular targets of GLP-1 have been found, but more remain to be identified. Elucidating these targets could be a basis for developing new potential drugs. My colleagues and I have investigated new targets of GLP-1, with a particular focus on pancreatic β-cell lines and hepatic cell lines. Herein, I summarize the recent work from my laboratory, with profound gratitude for receiving the prestigious 2016 Namgok Award.