Effects of glucagon-like peptide-1 receptor agonists on non-alcoholic fatty liver disease and inflammation

Non-alcoholic fatty liver disease in type 2 diabetes: Emerging evidence of benefit of peroxisome proliferator-activated receptors agonists and incretin-based therapies

Nonalcoholic fatty liver disease (NAFLD) is a global epidemic, affecting more than half of the people living with type 2 diabetes (T2D). The relationship between NAFLD and T2D is bidirectional and the presence of one perpetuates the other, which significantly increases the hepatic as well as extrahepatic complications. Until recently, there was no approved pharmacological treatment for NAFLD/ nonalcoholic steatohepatitits (NASH). However, there is evidence that drugs used for diabetes may have beneficial effects on NAFLD. Insulin sensitizers acting through peroxisome proliferator-activated receptor (PPAR) modulation act on multiple levels of NAFLD pathogenesis. Pioglitazone (PPARγ agonist) and saroglitazar (PPARα/γ agonist) are particularly beneficial and recommended by several authoritative bodies for treating NAFLD in T2D, although data on biopsy-proven NASH are lacking with the latter. Initial data on elafibanor (PPAR α/δ agonist) and Lanifibranor (pan PPAR agonist) are promising. On the other hand, incretin therapies based on glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1RA) and dual- and triple-hormone receptor co-agonists reported impressive weight loss and may have anti-inflammatory and antifibrotic properties. GLP-1 RAs have shown beneficial effects on NAFLD/NASH and more studies on potential direct effects on liver function by dual- and triple-agonists are required. Furthermore, the long-term safety of these therapies in NAFLD needs to be established. Collaborative efforts among healthcare providers such as primary care doctors, hepatologists, and endocrinologists are warranted for selecting patients for the best possible management of NAFLD in T2D.

The effect of GLP-1R agonists on the medical triad of obesity, diabetes, and cancer

Glucagon-like peptide-1 receptor (GLP-1R) agonists have garnered significant attention for their therapeutic potential in addressing the interconnected health challenges of diabetes, obesity, and cancer. The role of GLP-1R in type 2 diabetes mellitus (T2DM) is highlighted, emphasizing its pivotal contribution to glucose homeostasis, promoting β-cell proliferation, and facilitating insulin release. GLP-1R agonists have effectively managed obesity by reducing hunger, moderating food intake, and regulating body weight. Beyond diabetes and obesity, GLP-1R agonists exhibit a multifaceted impact on cancer progression across various malignancies. The mechanisms underlying these effects involve the modulation of signaling pathways associated with cell growth, survival, and metabolism. However, the current literature reveals a lack of in vivo studies on specific GLP-1R agonists such as semaglutide, necessitating further research to elucidate its precise mechanisms and effects, particularly in cancer. While other GLP-1R agonists have shown promising outcomes in mitigating cancer progression, the association between some GLP-1R agonists and an increased risk of cancer remains a topic requiring more profound investigation. This calls for more extensive research to unravel the intricate relationships between the GLP-1R agonist and different cancers, providing valuable insights for clinicians and researchers alike.

Management of Cardiovascular Risk in the Non-alcoholic Fatty Liver Disease Setting

Non-alcoholic fatty liver disease (NAFLD) is an overlooked and undetected pathology, which affects more than 32% of adults worldwide. NAFLD is becoming more common in Western industrialised countries, particularly in patients with central obesity, type 2 diabetes, dyslipidaemia and metabolic syndrome. Although NAFLD has traditionally been interpreted as a liver disease with a high risk of liver-related complications, NAFLD is an underappreciated and independent risk factor for atherosclerotic cardiovascular disease, which is the principal cause of death in patients with NAFLD. Treatment options to counteract both the progression and development of cardiovascular disease and NAFLD include lifestyle interventions, such as weight loss, increased physical activity and dietary modification, and optimal medical therapy of comorbid conditions; nevertheless, further studies are needed to define optimal treatment strategies for the prevention of both hepatic and cardiovascular complications of NAFLD.

GLP-1 receptor agonists in the treatment of diabetic non-alcoholic steatohepatitis patients

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is the most common hepatic disease affecting almost 30% of the world population. Approximately 25% of people with NAFLD develop nonalcoholic steatohepatitis (NASH), the fulminant version of the disease. Diabetes mellitus is present in 22.5% of people with NAFLD and 44.60% of individuals with NASH. This review was undertaken to examine the current contribution of glucagon-like peptide 1 (GLP-1) receptor agonists to the pharmacotherapy of diabetic nonalcoholic steatohepatitis.

AREAS COVERED

The author analyzed the current status of GLP-1 receptor agonists for pharmacotherapy of diabetic NASH. Research data and literature reports were taken from the database and or websites of Diabetes UK, American Diabetes Association, ClinicalTrials.gov, PubMed, and Scopus. The keywords utilized included type 2 diabetes, GLP-1, NASH, NAFLD, and clinical trials.

EXPERT OPINION

Since diabetic NASH is associated with obesity, diabetes mellitus, oxidative stress and inflammation, drugs capable of mitigating all of these conditions simultaneously, are most ideal for the treatment of diabetic NASH. These drugs include (in order of relevance), GLP-1 receptor agonists, GLP-1 and GIP dual receptor agonists, sodium-glucose co-transporter-2 (SGLT2) inhibitors, and pioglitazone. The future, FDA-approved drug for diabetic NASH treatment will likely be GLP-1 agonist, which could be used as monotherapy or in combination with other drugs.

Effects of liraglutide on intrapancreatic fat deposition in patients with type 2 diabetes

BACKGROUND & AIMS

Ectopic fat deposition is associated with worsening of glycemic control. This study was conducted to determine whether liraglutide reduces ectopic fat deposition, especially in pancreas, in patients with type 2 diabetes (T2D).

METHODS

We retrospectively recruited T2D patients who underwent abdominal unenhanced CT scans both before and after administration of liraglutide (N = 13) or glimepiride (N = 29). Using CT values of pancreas (P), liver (L) and spleen (S), we defined the indices of intrapancreatic and liver fat as P-S value and L-S value, respectively. Increase of each value suggests the reduction of each fat deposition.

RESULTS

The values of HbA1c (p = 0.0017) and body weight (p = 0.0081) decreased, and L-S (p = 0.0024) increased significantly after administration of liraglutide compared with those at baseline. Similarly, P-S tended to increase in the liraglutide group (p = 0.0547) and increased significantly in the liraglutide subgroup with fatty pancreas (p = 0.0303), defined as having baseline P-S less than -5. In the glimepiride group, P-S did not increase regardless of baseline P-S. Among patients with fatty pancreas, administration of liraglutide tended to be a significant factor for the change in P-S after adjustment for the change in HbA1c (p = 0.1090) and the change in visceral fat area (p = 0.1030).

CONCLUSIONS

Intrapancreatic fat deposition was decreased after treatment with liraglutide, but not glimepiride, in T2D patients with fatty pancreas. Liraglutide might reduce intrapancreatic fat deposition independently of decreases in HbA1c and visceral fat volume.

GLP-1/Sigma/RAGE receptors: An evolving picture of Alzheimer's disease pathology and treatment

According to the facts and figures 2023stated that 6.7 million Americans over the age of 65 have Alzheimer's disease (AD). The scenario of AD has reached up to the maximum, of 4.1 million individuals, 2/3rd are female patients, and approximately 1 in 9 adults over the age of 65 have dementia with AD dementia. The fact that there are now no viable treatments for AD indicates that the underlying disease mechanisms are not fully understood. The progressive neurodegenerative disease, AD is characterized by amyloid plaques and neurofibrillary tangles (NFTs) of abnormally hyperphosphorylated tau protein and senile plaques (SPs), which are brought on by the buildup of amyloid beta (Aβ). Numerous attempts have been made to produce compounds that interfere with these characteristics because of significant research efforts into the primary pathogenic hallmark of this disorder. Here, we summarize several research that highlights interesting therapy strategies and the neuroprotective effects of GLP-1, Sigma, and, AGE-RAGE receptors in pre-clinical and clinical AD models.

Incretins (GLP-1 receptor agonists and dual/triple agonists) and the liver

The principle pathological drivers of metabolic dysfunction-associated steatohepatitis (MASH) are obesity and associated insulin resistance, rendering them key therapeutic targets. As glucagon-like peptide 1 receptor agonists (GLP-1RAs) have been licensed for the treatment of diabetes and obesity, they were one of the first drug types to be evaluated in patients with MASH, and successful phase IIa and IIb studies have resulted in progression to phase III clinical trials. Alongside GLP-1RAs, newer combinations with glucagon agonists and/or glucose-dependent insulinotropic peptide (GIP) agonists have been explored in related patient groups, with evidence of improvements in weight, insulin resistance and non-invasive liver parameters. Whether GLP-1RAs have direct, independent effects on MASH or whether they impact on pathophysiology through improvements in weight, insulin resistance and glycaemic control remains a matter of debate. Combinations are being explored, although the potential improvement in efficacy will need to be weighed against the cumulative side-effect burden, potential drug-drug interactions and costs. There is also uncertainty regarding the optimal ratio of glucagon and GIP agonism to GLP-1 agonism in combination agents, and as to whether GIP agonism or antagonism is the optimal approach. Finally, there are also multiple hypothetical permutations combining gut hormone agonists with other emerging assets in the field. Given that the likely dominant mode of action of gut hormone agonists is upstream on weight, initial combinations might focus on agents which have been shown to have a more direct effect on fibrosis, which would include FGF21 and pan-PPAR agonists.

Impact of inflammation and anti-inflammatory modalities on diabetic cardiomyopathy healing: From fundamental research to therapy

Diabetic cardiomyopathy (DCM) is a prevalent cardiovascular complication of diabetes mellitus, characterized by high morbidity and mortality rates worldwide. However, treatment options for DCM remain limited. For decades, a substantial body of evidence has suggested that the inflammatory response plays a pivotal role in the development and progression of DCM. Notably, DCM is closely associated with alterations in inflammatory cells, exerting direct effects on major resident cells such as cardiomyocytes, vascular endothelial cells, and fibroblasts. These cellular changes subsequently contribute to the development of DCM. This article comprehensively analyzes cellular, animal, and human studies to summarize the latest insights into the impact of inflammation on DCM. Furthermore, the potential therapeutic effects of current anti-inflammatory drugs in the management of DCM are also taken into consideration. The ultimate goal of this work is to consolidate the existing literature on the inflammatory processes underlying DCM, providing clinicians with the necessary knowledge and tools to adopt a more efficient and evidence-based approach to managing this condition.

Anti-Diabetic Potential of Polyphenol-Rich Fruits from the Maleae Tribe-A Review of In Vitro and In Vivo Animal and Human Trials

The Maleae tribe consists of over one thousand species, including many well-known polyphenol-containing fruit crops with wide-ranging biological properties, e.g., apples (Malus), chokeberries (Aronia), pears (Pyrus), quinces (Cydonia, Chaenomeles), saskatoon (Amelanchier), loquats (Eriobotrya), medlars (Mespilus), rowans (Sorbus), and hawthorns (Crataegus). Considering the current interest in the concept of functional foods and the still-insufficient methods of diabetes management, the anti-diabetic potential of fruits has been studied intensively, including those of the Maleae tribe. This paper is the first comprehensive overview of this selected topic, covering articles published from 2000 to 2023 (131 articles in total). The first part of this review focuses on the potential mechanisms of action of fruits investigated so far (46 species), including their effects on tissue-specific glucose transport and the expression or activity of proteins in the insulin signalling pathway. The second part covers the phytocompounds responsible for particular fruits' activity-primarily polyphenols (e.g., flavonols, dihydrochalcones, proanthocyanidins, anthocyanins, phenolic acids), but also polysaccharides, triterpenes, and their additive and synergistic effects. In summary, fruits from the Maleae tribe seem promising as functional foods and anti-diabetic agents; however, their prospects for more expansive pro-health application require further research, especially more profound in vivo trials.

Therapeutic outcome of dapagliflozin in patients with type 2 diabetes and non-alcoholic fatty liver disease: a meta-analysis of randomized controlled trials

Introduction

The efficacy of dapagliflozin remains controversial for patients with type 2 diabetes and non-alcoholic fatty liver disease. We conduct this meta-analysis to explore the influence of dapagliflozin versus placebo on the treatment efficacy of type 2 diabetes complicated with non-alcoholic fatty liver disease.

Methods

We have searched PubMed, EMbase, Web of science, EBSCO, and Cochrane library databases through November 2021 for randomized controlled trials (RCTs) assessing the efficacy of dapagliflozin versus placebo for type 2 diabetes complicated with non-alcoholic fatty liver disease. This meta-analysis is performed using the random-effect model.

Results

Four RCTs are included in the meta-analysis. Overall, compared with patients with type 2 diabetes and non-alcoholic fatty liver disease, dapagliflozin treatment is associated with significantly reduced alanine aminotransferase (ALT, standard mean difference [SMD]=-1.27; 95% confidence interval [CI]span style="font-family: 'Times New Roman'">=-1.60 to -0.95; P<0.00001), aspartate-aminotransferase (AST, SMD=-1.37; 95% CI=-2.08 to -0.65; P=0.0002), fasting glucose (SMD=-0.78; 95% CI=-1.28 to -0.27; P=0.003) and HbA1c (SMD=-0.77; 95% CI=-1.21 to -0.34; P=0.0005), but demonstrated no obvious influence on homeostatic Model Assessment of Insulin Resistance (HOMA-IR, SMD=-0.36; 95% CI=-0.86 to 0.14; P=0.16).

Conclusions

Dapagliflozin benefits to improve hepatic function and glucose control in patients with type 2 diabetes and non-alcoholic fatty liver disease, as evidenced by the reduction in ALT, AST, fasting glucose and HbA1c.

Glucagon-like peptide-1: a multi-faceted anti-inflammatory agent

Inflammation contributes to many chronic conditions. It is often associated with circulating pro-inflammatory cytokines and immune cells. GLP-1 levels correlate with disease severity. They are often elevated and can serve as markers of inflammation. Previous studies have shown that oxytocin, hCG, ghrelin, alpha-MSH and ACTH have receptor-mediated anti-inflammatory properties that can rescue cells from damage and death. These peptides have been studied well in the past century. In contrast, GLP-1 and its anti-inflammatory properties have been recognized only recently. GLP-1 has been proven to be a useful adjuvant therapy in type-2 diabetes mellitus, metabolic syndrome, and hyperglycemia. It also lowers HbA1C and protects cells of the cardiovascular and nervous systems by reducing inflammation and apoptosis. In this review we have explored the link between GLP-1, inflammation, and sepsis.

Effects of treatment of non-alcoholic fatty liver disease on heart failure with preserved ejection fraction

In the past few decades, non-alcoholic fatty liver disease (NAFLD) and heart failure with preserved ejection fraction (HFpEF) have become the most common chronic liver disease and the main form of heart failure (HF), respectively. NAFLD is closely associated with HFpEF by sharing common risk factors and/or by boosting systemic inflammation, releasing other secretory factors, and having an expansion of epicardial adipose tissue (EAT). Therefore, the treatments of NAFLD may also affect the development and prognosis of HFpEF. However, no specific drugs for NAFLD have been approved by the Food and Drug Administration (FDA) and some non-specific treatments for NAFLD are applied in the clinic. Currently, the treatments of NAFLD can be divided into non-pharmacological and pharmacological treatments. Non-pharmacological treatments mainly include dietary intervention, weight loss by exercise, caloric restriction, and bariatric surgery. Pharmacological treatments mainly include administering statins, thiazolidinediones, glucagon-like peptide-1 receptor agonists, sodium-glucose cotransporter 2 inhibitors, and metformin. This review will mainly focus on analyzing how these treatments may affect the development and prognosis of HFpEF.

Shedding light on non-alcoholic fatty liver disease: Pathogenesis, molecular mechanisms, models, and emerging therapeutics

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder globally impacting an estimated 25% of the population associated with severe consequences such as cirrhosis, hepatocellular carcinoma (HCC), and overall mortality. Fatty liver disease is triggered through multiple pathways, but the most prominent cause is either diabetes or obesity, or a combination of both. Therefore, hepatic glucose, insulin and fatty acid signaling becomes a dire need to understand which is well elaborated in this review. This review summarizes the popular two-hit pathogenesis of NAFLD, the molecular mechanisms underlying hepatic insulin resistance. As fatty liver disease gets advanced, it requires in-vitro as well as in-vivo models closer to disease progression in humans for better understanding the pathological state and identifying a novel therapeutic target. This review summarizes in-vitro (2D cell-culture/co-culture, 3D spheroid/organoid/liver-on-a-chip) models as well as in-vivo (genetically/dietary/chemically induced fatty liver disease) research models. Fatty liver disease research has gathered lots of attention recently since there is no FDA approved therapy available so far. However, there have been numerous promising targets to treat fatty liver disease including potential therapeutic targets under clinical trials are listed in this review.

The Anti-Inflammatory Effect of Novel Antidiabetic Agents

The incidence of type 2 diabetes (T2DM) has been increasing worldwide and remains one of the leading causes of atherosclerotic disease. Several antidiabetic agents have been introduced in trying to regulate glucose control levels with different mechanisms of action. These agents, and sodium-glucose cotransporter-2 inhibitors in particular, have been endorsed by contemporary guidelines in patients with or without T2DM. Their widespread usage during the last three decades has raised awareness in the scientific community concerning their pleiotropic mechanisms of action, including their putative anti-inflammatory effect. In this review, we delve into the anti-inflammatory role and mechanism of the existing antidiabetic agents in the cardiovascular system and their potential use in other chronic sterile inflammatory conditions.

Pharmacotherapy for Non-alcoholic Fatty Liver Disease Associated with Diabetes Mellitus Type 2

Non-alcoholic fatty liver disease (NAFLD) and diabetes mellitus type 2 commonly coexist as a manifestation of metabolic syndrome. The presence of diabetes promotes the progression of simple fatty liver to non-alcoholic steatohepatitis (NASH) and cirrhosis, and the presence of NAFLD increases the risk of diabetic complications. This coexistence affects a large part of the population, imposing a great burden on health care systems worldwide. Apart from diet modification and exercise, recent advances in the pharmacotherapy of diabetes offer new prospects regarding liver steatosis and steatohepatitis improvement, enriching the existing algorithm and supporting a multifaceted approach to diabetic patients with fatty liver disease. These agents mainly include members of the families of glucagon-like peptide-1 analogues and the sodium-glucose co-transporter-2 inhibitors. In addition, agents acting on more than one receptor simultaneously are presently under study, in an attempt to further enhance our available options.

Spotlight on liver macrophages for halting injury and progression in non-alcoholic fatty liver disease

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) is considered the hepatic manifestation of the metabolic syndrome and is rapidly emerging as the leading cause of liver-related morbidity and mortality. Macrophages play an essential role in the development and progression of NAFLD.

AREAS COVERED

In this review, we provide an update on recent studies of drugs, which directly or indirectly affect macrophages in NAFLD, and discuss the implication of macrophage biomarkers to monitor the disease stage and progression/regression.

EXPERT OPINION

There is an unmet need for better understanding of disease pathogenesis from hepatic fat accumulation to disease progression with inflammation and fibrosis. We expect that future research will uncover additional objects/pathways as treatment targets. We speculate that this will involve better characterization of the gut microbiome, damage-associated molecular patterns (DAMPS) or molecules and pathways involved in development of DAMPS, and advanced molecular biology studies including single-cell sequencing of macrophage subpopulations. In addition, we speculate that studies focusing on pharmaceuticals that improve insulin resistance, diminish the metabolic syndrome and reduce fibrosis will prevail.

Effect of novel glucose lowering agents on non-alcoholic fatty liver disease: A systematic review and meta-analysis

BACKGROUND

The efficacy of novel glucose-lowering drugs in treating non-alcoholic fatty liver disease (NAFLD) in patients with and without type-2 diabetic patients (T2DM) remains unclear.

AIM

To conduct a meta-analysis to evaluate the efficacy of 3 novel glucose-lowering drug classes, namely glucagon-like peptide-1 receptor agonists (GLP-1RA), sodium-glucose co-transporter 2 (SGLT2) inhibitors, and dipeptidyl-peptidase-4 (DPP4) inhibitors on hepatic parameters: Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), Gamma-Glutamyl Transferase (GGT), Bilirubin, and FIB-4 (Fibrosis).

METHODS

MEDLINE was searched from inception through October 2021 for randomized placebo or active glucose-lowering drug-controlled trials. A random-effects model was used to pool the results. A p-value of less than or equal to 0.05 was considered significant. Results were presented as weighted mean differences (WMD) and corresponding 95% confidence intervals (CIs).

RESULTS

Our pooled analysis consisted of 40 studies. A significant reduction was seen in AST with SGLT2 inhibitors (WMD = -2.31 IU/L, 95%CI: -3.16 to -1.47 IU/L, P < 0.00001) and GLP-1RA (WMD = -3.29 IU/L, 95%CI: -5.98 to -0.61 IU/L, P = 0.02). Similarly, significant reduction was seen in ALT with SGLT2 inhibitors (WMD = -5.93 IU/L, 95%CI: -7.70 to -4.16 IU/L, P < 0.00001) and GLP-1RAs (WMD = -9.92 IU/L, 95%CI: -19.89 to 0.05 IU/L, P = 0.05). In contrast, DPP-4 inhibitors showed no significant reduction in AST (WMD = -3.20 IU/L, 95%CI: -11.13 to 4.73 IU/L, P = 0.43) or ALT (WMD = -4.81 IU/L, 95%CI: -15.83 to 6.21 IU/L, P = 0.39). A significant reduction in GGT was seen with SGLT2 inhibitors (WMD = -6.49 IU/L, 95%CI: -11.09 to -1.89 IU/L, P = 0.006) and GLP-1RAs (WMD = -12.38 IU/L, 95%CI: -15.69 to -9.07 IU/L, P < 0.00001). However, significant results were not observed with DPP-4 inhibitors (WMD = -0.92 IU/L, 95%CI: -5.80 to 3.96 IU/L, P = 0.71). There was a statistically significant reduction in FIB-4 index with SGLT2 inhibitors (WMD = -0.21, 95%CI: -0.40 to -0.03, P = 0.02) and GLP-1 RA (WMD = -0.15, 95%CI: -0.29 to 0.00, P = 0.05). Lastly, SGLT2 inhibitors led to a significant change in bilirubin levels (WMD = 2.03, 95%CI: 0.76 to 3.30, P = 0.002) while the change in bilirubin was not significant with GLP-1 agonists (WMD = -0.21, 95%CI: -1.09 to 0.66, P = 0.63) and DPP-4 inhibitors (WMD = 0.14, 95%CI: -1.55 to 1.83, P = 0.87).

CONCLUSION

SGLT2 inhibitors and GLP-1 agonists have a beneficial effect on hepatic parameters in patients with NAFLD. However, further research is needed to evaluate the effect of DPP-4 inhibitors on hepatic function properly.

Anti-Inflammatory Effects of GLP-1 Receptor Activation in the Brain in Neurodegenerative Diseases

The glucagon-like peptide-1 (GLP-1) is a pleiotropic hormone well known for its incretin effect in the glucose-dependent stimulation of insulin secretion. However, GLP-1 is also produced in the brain and displays a critical role in neuroprotection and inflammation by activating the GLP-1 receptor signaling pathways. Several studies in vivo and in vitro using preclinical models of neurodegenerative diseases show that GLP-1R activation has anti-inflammatory properties. This review explores the molecular mechanistic action of GLP-1 RAS in relation to inflammation in the brain. These findings update our knowledge of the potential benefits of GLP-1RAS actions in reducing the inflammatory response. These molecules emerge as a potential therapeutic tool in treating neurodegenerative diseases and neuroinflammatory pathologies.

Semaglutide might be a key for breaking the vicious cycle of metabolically associated fatty liver disease spectrum?

Metabolically associated fatty liver disease (MAFLD) is a liver manifestation of metabolic syndrome potentially related to unfavorable hepatic and extrahepatic outcomes and progression to cirrhosis. Up to date, there are no approved pharmacotherapies for the treatment of MAFLD, so management focused on lifestyle interventions to encourage weight loss, and treatment of coexisting conditions is the only available option. Unfortunately, the aforementioned is often not potent enough to offer reversal or slow down hepatic inflammation and fibrosis. Glucagon-like peptide-1 receptor agonists have a favorable effect on glycemic management and weight loss of patients with type 2 diabetes mellitus and recently published data suggest their potential in MAFLD treatment. In addition, some of the agents have proven cardiovascular and renal benefits in dedicated cardiovascular outcome trials, making them an interesting therapeutic option. In this opinion review, we discuss the role of semaglutide in MAFLD.

Nonalcoholic Steatohepatitis (NASH) and Atherosclerosis: Explaining Their Pathophysiology, Association and the Role of Incretin-Based Drugs

Nonalcoholic steatohepatitis (NASH) is the most severe manifestation of nonalcoholic fatty liver disease (NAFLD), a common complication of type 2 diabetes, and may lead to cirrhosis and hepatocellular carcinoma. Oxidative stress and liver cell damage are the major triggers of the severe hepatic inflammation that characterizes NASH, which is highly correlated with atherosclerosis and coronary artery disease. Regarding drug therapy, research on the role of GLP-1 analogues and DPP4 inhibitors, novel classes of antidiabetic drugs, is growing. In this review, we outline the association between NASH and atherosclerosis, the underlying molecular mechanisms, and the effects of incretin-based drugs, especially GLP-1 RAs, for the therapeutic management of these conditions.

Inflammatory Mechanisms of Diabetes and Its Vascular Complications

The main cause of death in patients with type 2 DM is cardiovascular complications resulting from the progression of atherosclerosis. The pathophysiology of the association between diabetes and its vascular complications is complex and multifactorial and closely related to the toxic effects of hyperglycemia that causes increased generation of reactive oxygen species and promotes the secretion of pro-inflammatory cytokines. Subsequent oxidative stress and inflammation are major factors of the progression of type 2 DM and its vascular complications. Data on the pathogenesis of the development of type 2 DM and associated cardiovascular diseases, in particular atherosclerosis, open up broad prospects for the further development of new diagnostic and therapeutic approaches.

Pharmacotherapy for Non-Alcoholic Fatty Liver Disease: Emerging Targets and Drug Candidates

Non-alcoholic fatty liver disease (NAFLD), or metabolic (dysfunction)-associated fatty liver disease (MAFLD), is characterized by high global incidence and prevalence, a tight association with common metabolic comorbidities, and a substantial risk of progression and associated mortality. Despite the increasingly high medical and socioeconomic burden of NAFLD, the lack of approved pharmacotherapy regimens remains an unsolved issue. In this paper, we aimed to provide an update on the rapidly changing therapeutic landscape and highlight the major novel approaches to the treatment of this disease. In addition to describing the biomolecules and pathways identified as upcoming pharmacological targets for NAFLD, we reviewed the current status of drug discovery and development pipeline with a special focus on recent evidence from clinical trials.

Efficacy and safety of semaglutide for weight management: evidence from the STEP program

Obesity is a global health challenge. It is a multifactorial, complex, and progressive disease associated with various health complications and increased mortality. Lifestyle modifications are central to weight management but may be insufficient to maintain clinically meaningful weight loss. Pharmacotherapies are recommended as an adjunct to lifestyle interventions to induce and sustain clinically meaningful weight loss and reduce the risk of comorbidities in appropriate patients. Glucagon-like peptide-1 is an incretin metabolic hormone responsible for a range of physiological effects, including glucose and appetite regulation. Several glucagon-like peptide-1 receptor agonists (GLP-1RAs) have been approved for the treatment of type 2 diabetes since 2005 including exenatide (short- and extended-release), lixisenatide, liraglutide, dulaglutide, albiglutide, and semaglutide. Of these, semaglutide (subcutaneous) and liraglutide are currently US Food and Drug Administration (FDA)-approved for chronic weight management in patients with or without diabetes. The phase 3 Semaglutide Treatment Effect in People with obesity (STEP) program was designed to investigate the effect of semaglutide versus placebo on weight loss, safety, and tolerability in adults with overweight or obesity. Following the submission of the results of the STEP 1-4 trials, the FDA approved once-weekly subcutaneous semaglutide 2.4 mg for chronic weight management in people with overweight or obesity in April 2021. Data from the program demonstrated that semaglutide (2.4 mg once weekly) achieved significant and sustained weight loss, together with improvements in cardiometabolic risk factors compared with placebo, and was generally well tolerated, with a safety profile consistent with other GLP-1RAs. The most common adverse events reported in STEP 1-5 were gastrointestinal events, which were transient, mild-to-moderate in severity, and typically resolved without permanent treatment discontinuation. This article reviews the data from STEP 1-5 and highlights clinically relevant findings for primary care providers.

Narrative review of current and emerging pharmacological therapies for nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is the most common cause of chronic liver disease today, and it has now emerged as the leading etiology of end-stage liver disease requiring liver transplantation. It is a progressive form of non-alcoholic fatty liver disease which can not only progress to cirrhosis of liver and hepatocellular carcinoma (HCC), but is associated with increased cardiovascular risks too. Despite all the advances in the understanding of the risk factors and the pathogenetic pathways involved in the pathogenesis and progression of NASH, an effective therapy for NASH has not been developed yet. Although lifestyle modifications including dietary modifications and physical activity remain the mainstay of therapy, there is an unmet need to develop a drug or a combination of drugs which can not only reduce the fatty infiltration of the liver, but also arrest the development and progression of fibrosis and advancement to cirrhosis of liver and HCC. The pharmacologic therapies which are being developed target the various components believed to be involved in the pathogenesis of nonalcoholic fatty liver disease (NAFLD)/NASH which includes insulin resistance, lipid metabolism oxidative stress, lipid peroxidation, inflammatory and cell death pathways, and fibrosis. In this review, we summarize the current state of knowledge on pharmacotherapy of NASH, and also highlight the recent developments in the field, for optimizing the management and treatment of NASH.

Cellular protein markers, therapeutics, and drug delivery strategies in the treatment of diabetes-associated liver fibrosis

Liver fibrosis is the excessive accumulation of extracellular matrix due to chronic injuries, such as viral infection, alcohol abuse, high-fat diet, and toxins. Liver fibrosis is reversible before it progresses to cirrhosis and hepatocellular carcinoma. Type 2 diabetes significantly increases the risk of developing various complications including liver diseases. Abundant evidence suggests that type 2 diabetes and liver diseases are bidirectionally associated. Patients with type 2 diabetes experience more severe symptoms and accelerated progression of live diseases. Obesity and insulin resistance resulting from hyperlipidemia and hyperglycemia are regarded as the two major risk factors that link type 2 diabetes and liver fibrosis. This review summarizes possible mechanisms of the association between type 2 diabetes and liver fibrosis. The cellular protein markers that can be used for diagnosis and therapy of type 2 diabetes-associated liver fibrosis are discussed. We also highlight the potential therapeutic agents and their delivery systems that have been investigated for type 2 diabetes-associated liver fibrosis.

Proglucagon-Derived Peptides as Therapeutics

Initially discovered as an impurity in insulin preparations, our understanding of the hyperglycaemic hormone glucagon has evolved markedly over subsequent decades. With description of the precursor proglucagon, we now appreciate that glucagon was just the first proglucagon-derived peptide (PGDP) to be characterised. Other bioactive members of the PGDP family include glucagon-like peptides -1 and -2 (GLP-1 and GLP-2), oxyntomodulin (OXM), glicentin and glicentin-related pancreatic peptide (GRPP), with these being produced via tissue-specific processing of proglucagon by the prohormone convertase (PC) enzymes, PC1/3 and PC2. PGDP peptides exert unique physiological effects that influence metabolism and energy regulation, which has witnessed several of them exploited in the form of long-acting, enzymatically resistant analogues for treatment of various pathologies. As such, intramuscular glucagon is well established in rescue of hypoglycaemia, while GLP-2 analogues are indicated in the management of short bowel syndrome. Furthermore, since approval of the first GLP-1 mimetic for the management of Type 2 diabetes mellitus (T2DM) in 2005, GLP-1 therapeutics have become a mainstay of T2DM management due to multifaceted and sustainable improvements in glycaemia, appetite control and weight loss. More recently, longer-acting PGDP therapeutics have been developed, while newfound benefits on cardioprotection, bone health, renal and liver function and cognition have been uncovered. In the present article, we discuss the physiology of PGDP peptides and their therapeutic applications, with a focus on successful design of analogues including dual and triple PGDP receptor agonists currently in clinical development.

Efficacy of GLP-1rA, liraglutide, in plaque psoriasis treatment with type 2 diabetes: a systematic review and meta-analysis of prospective cohort and before-after studies

BACKGROUND

Psoriasis usually accompanies comorbidities such as type 2 diabetes, obesity, and cardiovascular disease. It has been proposed that glucagon-like peptide-1 receptor (GLP-1R) agonists used in the treatment of patients with type 2 diabetes may also improve psoriasis. However, the number of patients in every single study is relatively small.

OBJECTIVES

We carried out a meta-analysis to evaluate whether GLP-1R is effective for the treatment of plaque psoriasis with type 2 diabetes.

METHODS

A search of PubMed, Ovid Embase, the Cochrane Library for controlled trials was done from inception to June 20th, 2020. Published trials that included psoriasis patients with type 2 diabetes, the Psoriasis Area and Severity Index (PASI) of treated by GLP-1R before and after. All statistical analyses were conducted using the Stata 15.0 (Stata Corporation, College Station, TX, USA).

RESULTS

There were 4 trials involving 32 patients. Patients treated by GLP-1R after showed significantly lower PASI (SMD: -4.332, 95% CI: -7.611 to -1.053, p = .01), lower fasting plasma glucose than treated before (SMD: -0.341, 95% CI: -0.679 to -0.004, p = .048). There was no significant difference in Body Mass Index (BMI), Dermatology Life Quality Index (DLQI), and glycated hemoglobin (HbA1c) between treated by GLP-1R after and before.

CONCLUSIONS

GLP-1rA, liraglutide, therapy can reduce psoriasis who had concomitant type 2 diabetes severity, but may independently of changes in weight and glycaemic control.

Glucagon-like Peptide-1 Improves Fatty Liver and Enhances Thermogenesis in Brown Adipose Tissue via Inhibiting BMP4-Related Signaling Pathway in High-Fat-Diet-Induced Obese Mice

OBJECTIVE

Glucagon-like peptide-1 (GLP-1) receptor agonist is effective in decreasing blood glucose and body weight. It could improve fatty liver with unclear mechanisms. Hence, we aimed to explore whether GLP-1 could improve fatty liver by regulating the BMP4-related signaling pathway.

METHODS

Fifteen C57BL/6 mice were randomly assigned to 3 groups. Group A and Group B were fed with a high-fat diet (HFD) to induce fatty liver while Group C was fed with a regular diet (RD) for 24 weeks. Group A and Group B received a subcutaneous injection of exenatide and vehicle (0.9% NaCl), respectively, once daily at doses of 10 nmol/kg during the last 8 weeks. Bodyweight, liver weight, and lipid levels were measured. Histological analyses of liver tissue were performed. The expression of protein and gene measured by western blotting and real-time polymerase chain reaction (RT-PCR) was compared.

RESULTS

Eight-week exenatide treatment significantly decreased body weight in Group A (from 44.08 ± 2.89 g to 39.22 ± 1.88 g, P = 0.045). Group A had lower body weight and liver weight than Group B at 24 weeks (39.22 ± 1.88 g vs. 47.34 ± 2.43 g, P = 0.001 and 1.70 ± 0.20 g vs. 2.48 ± 0.19 g, P = 0.001, respectively). Moreover, Group A showed significantly less liver steatosis than Group B. Additionally, Group A led to slightly decreased serum triglyceride (TG) and cholesterol (TC) levels compared to Group B. Western blotting showed that exenatide could prevent HFD-induced upregulation of BMP4 levels and downstream activation of Smad1/5/8 and the P38 MAPK signaling pathway in the liver. Furthermore, exenatide treatment could reduce BMP4 and enhance UCP-1 (an important thermogenin) in brown adipose tissue (BAT).

CONCLUSION

Exenatide could improve HFD-induced hepatic steatosis and enhance thermogenesis in BAT, which may be partly attributed to the inhibition of the BMP4-related signaling pathway.

Current treatment paradigms and emerging therapies for NAFLD/NASH

Non-alcoholic fatty liver disease (NAFLD) is one the fastest emerging manifestations of the metabolic syndrome worldwide. Non-alcoholic steatohepatitis (NASH), the progressive form of NAFLD, may culminate into cirrhosis and hepatocellular cancer (HCC) and is presently a leading cause of liver transplant. Although a steady progress is seen in understanding of the disease epidemiology, pathogenesis and identifying therapeutic targets, the slowest advancement is seen in the therapeutic field. Currently, there is no FDA approved therapy for this disease and appropriate therapeutic targets are urgently warranted. In this review we discuss the role of lifestyle intervention, pharmacological agents, surgical approaches, and gut microbiome, with regard to therapy for NASH. In particular, we focus the role of insulin sensitizers, thyroid hormone mimetics, antioxidants, cholesterol lowering drugs, incretins and cytokines as therapeutic targets for NASH. We highlight these targets aiming to optimize the future for NASH therapy.

PNPLA3 I148M is involved in the variability in anti-NAFLD response to exenatide

PURPOSE

GLP-1 receptor agonists, such as exenatide, have been proven to attenuate nonalcoholic fatty liver disease (NAFLD) in vivo and in vitro. However, the efficiency of exenatide had interindividual differences. PNPLA3 is a major susceptibility gene for NAFLD and its I148M polymorphism increases the risk of all disorders of the NAFLD spectrum. Whether this variant contributes to variability in exenatide response is still unclear.

METHODS

PNPLA3 148I knockin HepG2 cells were constructed using the Cas9/sgRNA system. Oil Red O staining combined with TG quantification was used to evaluate lipid accumulation. Western blotting and qRT-qPCR were conducted, respectively, to measure the protein and mRNA expression of lipid metabolic and endoplasmic reticulum (ER) stress-related inflammatory markers. PNPLA3 I148M was genotyped in type 2 diabetics using Sanger sequencing. The exenatide-induced changes in liver fat content and other clinical parameters were compared between PNPLA3 I148M genotypes.

RESULTS

Lipid deposition increased in both PNPLA3 148I/I and 148M/M HepG2 cells treated with palmitoleic acid, while cells with 148M/M had a higher TG content than those with 148I/I. Exendin-4 treatment was showed to be more significant in 148I/I cells than in 148M/M cells in terms of reducing the intrahepatic fat content, inhibiting SREBP-1c and ER stress-related inflammation, and activating AMPK-ACC lipid oxidation pathway. In patients with type 2 diabetes, 24-week treatment with exenatide improved liver fat content in patients carrying PNPLA3 148I/I better than in patients with 148M/M.

CONCLUSIONS

PNPLA3 I148M might modify the anti-NAFLD response to exenatide.

A look to the future in non-alcoholic fatty liver disease: Are glucagon-like peptide-1 analogues or sodium-glucose co-transporter-2 inhibitors the answer?

The increasing prevalence of diabetes and non-alcoholic fatty liver disease (NAFLD) is a growing public health concern associated with significant morbidity, mortality and economic cost, particularly in those who progress to cirrhosis. Medical treatment is frequently limited, with no specific licensed treatments currently available for people with NAFLD. Its association with diabetes raises the possibility of shared mechanisms of disease progression and treatment. With the ever-growing interest in the non-glycaemic effects of diabetes medications, studies and clinical trials have investigated hepatic outcomes associated with the use of drug classes used for people with type 2 diabetes (T2D), such as glucagon-like peptide-1 (GLP-1) analogues or sodium-glucose co-transporter-2 (SGLT2) inhibitors. Studies exploring the use of GLP-1 analogues or SGLT2 inhibitors in people with NAFLD have observed improved measures of hepatic inflammation, liver enzymes and radiological features over short periods. However, these studies tend to have variable study populations and inconsistent reported outcomes, limiting comparison between drugs and drug classes. As these drugs appear to improve biomarkers of NAFLD, clinicians should consider their use in patients with NAFLD and T2D. However, further evidence with greater participant numbers and longer trial durations is required to support specific licensing for people with NAFLD. Larger trials would allow reporting of major adverse hepatic events, akin to cardiovascular and renal outcome trials, to be determined. This would provide a more meaningful evaluation of the impact of these drugs in NAFLD. Nevertheless, these drugs represent a future potential therapeutic avenue in this difficult-to-treat population and may beget significant health and economic impacts.

Glucagon-like peptide-1 receptor is expressed in human and rodent testis

BACKGROUND

The incretin hormone glucagon-like peptide-l (GLP-1) is an important regulator of post-prandial insulin secretion, acting through a G protein-coupled cell surface receptor (GLP-1R). In addition to its expression in pancreatic β-cells, several studies suggested that GLP-1R is located in extra-pancreatic tissues.

OBJECTIVES

In this study, we examined for the first time the testicular distribution of the GLP-1R, both in normal human and neoplastic testicular tissues as well as in rodent testis and rodent testicular cell lines.

METHODS AND METHODS

The GLP-1R distribution in testicular section has been evaluated by immunohistochemistry, the specificity of IHC was validated by demonstrating a positive staining for GLP-1RmRNA by RISH technology. While GLP-1R expression in terms of protein was detected by western blot analysis, Moreover, mRNA levels were determined in human testis, in rodent Leydig, and Sertoli cell lines.

RESULTS

Using immunohistochemistrya specific staining for GLP-1R was detected in Leydig cells. The specificity of IHC was validated by demonstrating a positive staining for GLP-1RmRNA only in these cell types. Species differences in the GLP-1R expression between humans and rodents were observed. Interestingly, a decreased expression of the receptor in rodent tumor Leydig cell line and an absence in human Leydig tumor samples was detected.

DISCUSSION

It may be hypothesized that GLP-1R acts like an oncosuppressor in Leydig tumors. A role in regulation of hormone secretion by GLP-1 has been shown in other endocrine cells, therefore we hypothesized that GLP-1R is able to modulate somehow the Leydig cell function.

CONCLUSION

In our findings, a careful evaluation of human testicular tissues and rodent testis revealed Leydig cells as a potential target for GLP-1. Collectively, an effect of GLP-1R in Leydig cell function may be presumed although future studies are needed to ascertain the GLP-1R's role both in normal and tumor Leydig cells.

Proper Management of People with Obesity during the COVID-19 Pandemic

Since December 2019, countries around the world have been struggling with a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Case series have reported that people with obesity experience more severe coronavirus disease 2019 (COVID-19). During the COVID-19 pandemic, people have tended to gain weight because of environmental factors imposed by quarantine policies, such as decreased physical activity and increased consumption of unhealthy food. Mechanisms have been postulated to explain the association between COVID-19 and obesity. COVID-19 aggravates inflammation and hypoxia in people with obesity, which can lead to severe illness and the need for intensive care. The immune system is compromised in people with obesity and COVID-19 affects the immune system, which can lead to complications. Interleukin-6 and other cytokines play an important role in the progression of COVID-19. The inflammatory response, critical illness, and underlying risk factors may all predispose to complications of obesity such as diabetes mellitus and cardiovascular diseases. The common medications used to treat people with obesity, such as glucagon-like peptide-1 analogues, statins, and antiplatelets agents, should be continued because these agents have anti-inflammatory properties and play protective roles against cardiovascular and all-cause mortality. It is also recommended that renin–angiotensin system blockers are not stopped during the COVID-19 pandemic because no definitive data about the harm or benefits of these agents have been reported. During the COVID-19 pandemic, social activities have been discouraged and exercise facilities have been closed. Under these restrictions, tailored lifestyle modifications such as home exercise training and cooking of healthy food are encouraged.

A Systematic Review of Newer Antidiabetic Agents in the Treatment of Nonalcoholic Fatty Liver Disease

OBJECTIVE

To evaluate glucagon-like peptide 1 receptor agonists (GLP-1 RAs), dipeptidyl-peptidase IV (DPP-4) inhibitors, and sodium-glucose cotransporter 2 (SGLT) inhibitors to treat nondiabetic and type 2 diabetes mellitus (T2DM) nonalcoholic fatty liver disease (NAFLD) as it relates to improvement in hepatosteatosis (HS) or steatohepatitis (SH).

DATA SOURCES

MEDLINE and CINAHL were searched from inception through May 1, 2020. Search terms included nonalcoholic steatohepatitis, nonalcoholic fatty liver disease, fatty liver, dipeptidyl-peptidase IV inhibitors, glucagon-like peptide-1 receptor agonists, and sodium-glucose transporter 2 inhibitors.

STUDY SELECTION AND DATA EXTRACTION

Full-text observational and randomized controlled studies in English were included. Patients diagnosed with NAFLD, treated with GLP-1 RAs, DPP-4 inhibitors, and SGLT2 inhibitors, with measures to evaluate HS or SH were evaluated.

DATA SYNTHESIS

Eight GLP-1 RA trials were reviewed; 7 GLP-1 RA trials showed improvement in HS. Two studies demonstrated improvement in liver histology in patients with SH. Seven SGLT2 inhibitor studies were reviewed; 6 studies demonstrated improvements in NAFLD. Five studies showed improvements in HS, whereas 1 displayed improvement in liver histology in NASH. Six studies that included DPP-4 inhibitors were evaluated, and only 2 demonstrated improvement in NASH.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Based on evidence reviewed, GLP-1 RAs and SGLT2 inhibitors decreased HS and SH in NAFLD patients, whereas DPP-4 inhibitor therapy was not effective for patients with HS.

CONCLUSIONS

Based on study data utilizing imaging studies and biopsy results, GLP-1 RAs or SGLT2 inhibitors can benefit NAFLD T2DM patients. Clinical trials with larger patient populations may augment these results.

A Review Of Current And Upcoming Treatment Modalities In Non-Alcoholic Fatty Liver Disease And Non-Alcoholic Steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the West. Non-alcoholic steatohepatitis (NASH) is the progressive form of NAFLD and can lead to cirrhosis, hepatocellular carcinoma, and is associated with increased cardiovascular risks. Multiple components and risk factors are thought to be involved in the pathogenesis of NAFLD and NASH. Optimal therapy has not yet been found, but many advances have been made with the discovery of potential therapeutic options. In this paper, we aim to provide a comprehensive review of approved, studied, and upcoming treatment options for NAFLD and NASH. Non-pharmacologic therapy (lifestyle modifications and bariatric surgery) and pharmacologic therapy are both reviewed. Pharmacologic therapy target components thought to be involved in the pathogenesis of this disease process including insulin resistance, oxidative stress, inflammation, lipid metabolism, and fibrosis are reviewed in this paper. Results of the emerging treatment targets in phase 2 and 3 clinical trials are also included.

The investigation of therapeutic potential of oxytocin and liraglutide on vincristine-induced neuropathy in rats

The aim of this study was to assess the therapeutic potential of oxytocin and liraglutide (LIR), a GLP-1 analogue, in a rat model of vincristine-induced neuropathy. Rats were injected with vincristine (VCR) at a dose of 4 mg/kg twice a week for 5 weeks. The VCR-administered rats were divided into three groups and received saline, oxytocin, or liraglutide simultaneously with VCR. After the treatment period, electrophysiological, biochemical, histological, and immunohistochemical investigations were performed. Electromyography (EMG) recordings demonstrated significant alterations in the VCR + saline group (p < .001). Also, motor performance was decreased in the VCR + saline group (p < .05). Histologically, the axonal diameter was decreased in all groups. VCR + saline group showed significantly increased lipid peroxidation and decreased nerve growth factor (NGF) expression. However, the administration of oxytocin and liraglutide significantly prevented the EMG alterations, lipid peroxidation, and reduction in neuronal NGF expression. On the basis of these findings, oxytocin and liraglutide may be considered as potential agents for the prevention of VCR-induced neuropathy.

Consensus Recommendations on GLP-1 RA Use in the Management of Type 2 Diabetes Mellitus: South Asian Task Force

The advent of incretin mimetics such as glucagon-like peptide-1 receptor agonists (GLP-1 RAs) has enriched the armamentarium for diabetes management owing to their glycaemic as well as extra-glycaemic benefits. The approval status and availability of this class of drugs vary widely across the globe. Being a relatively newer class of drug with numerous benefits, several national and international guidelines are working towards addressing clinical questions pertaining to the optimal use of GLP-1 RAs for the management of diabetes. Although the newer class of drugs are associated with significant benefits such as patient-centric approach, these drugs demand the providers to be vigilant and knowledgeable about the medication. The South Asian population is at higher risk of type 2 diabetes mellitus (T2DM) because of their genetic predisposition and lifestyle changes. Hence, prevention and management of T2DM and its associated complications in this population are of paramount importance. The current report aims to present an overview of current knowledge on GLP-1 RAs based on pragmatic review of the available clinical evidence. In addition, this report is a consensus of expert endocrinologists representing South Asian countries including India, Pakistan, Bangladesh, Nepal, Sri Lanka, Afghanistan and the Maldives on essential recommendations related to the use of GLP-1 RAs in a real-world scenario.

Exendin-4 regulates Wnt and NF-κB signaling in lipopolysaccharide-induced human periodontal ligament stem cells to promote osteogenic differentiation

A major feature of chronic periodontitis (CP) is the damage and destruction of alveolar bone. Periodontal ligament stem cells (PDLSCs) can differentiate into bone and improve CP. Exendin-4 (Ex-4) has been shown to have anti-inflammatory mechanisms and can promote bone regeneration. However, the effects of Ex-4 on the osteogenic differentiation of PDLSCs in the inflammatory microenvironment remains uncharacterized. In this study, we assessed the effects of Ex-4 on PDLSCs stimulated with lipopolysaccharide (LPS) to mimic the inflammatory environment. PDLSCs proliferation was assessed through CCK-8 assays and osteogenic differentiation was measured using Alizarin Red staining. The anti-inflammatory and osteogenic mechanisms of Ex-4 were assessed by western blot, RT-PCR, ELISA and immunofluorescence. We found that LPS treatment promoted the proliferative capacity of PDLSCs and inhibited their osteogenic differentiation. However, Ex-4 reversed these effects through suppressing PDLSCs proliferation and promoting osteogenic differentiation. Ex-4 increased Runx2, ALP, and Osx levels and decreased TNF-α and IL-6 expression. Ex-4 also reduced the expression of IκBα and p-IκBα, and inhibited the nuclear translocation of NF-κB/p65. The expression of β-catenin decreased in nucleus after co-treatment of Ex-4 with LPS. Taken together, these data demonstrate that Ex-4 promotes PDLSCs osteogenic differentiation in the inflammatory microenvironment through regulating NF-κB and Wnt signaling.

LRG ameliorates steatohepatitis by activating the AMPK/mTOR/SREBP1 signaling pathway in C57BL/6J mice fed a high‑fat diet

The pathogenesis of nonalcoholic fatty liver disease non‑alcoholic steatohepatitis (NASH) has not been fully elucidated, and there are currently no effective treatments for NASH. The aim of the present study was to explore the therapeutic effects of the glucagon‑like peptide‑1 (GLP‑1) receptor agonist liraglutide (LRG) on NASH and the underlying mechanisms. C57BL6J mice were fed a high‑fat diet (HFD) for 8 weeks to induce hepatic steatosis, and then LRG was injected subcutaneously for 4 weeks. The expression of sterol regulatory element‑binding protein 1 (SREBP1) and adenosine monophosphate‑activated protein kinase (AMPK) as well as the phosphorylation of mechanistic target of rapamycin (mTOR) and p70 ribosomal S6 kinase (p70S6K) were determined by western blot analysis. The intracellular distribution of SREBP1 was assessed by immunofluorescence staining. The results revealed that LRG treatment ameliorated HFD‑induced hepatic lipid accumulation and inhibited body weight gain. In addition, LRG treatment significantly suppressed the expression of hepatic SREBP1 as well as the phosphorylation of mTOR and p70S6K; it also increased the phosphorylation of AMPK and acetyl coenzyme A carboxylase. Furthermore, LRG treatment inhibited the hepatic nuclear translocation of SREBP1. It was suggested that the GLP‑1 receptor agonist LRG may have ameliorated hepatic steatosis by activating the AMPK/mTOR/SREBP1 signaling pathway as opposed to inhibiting body weight gain.

Anti-inflammatory properties of antidiabetic agents

The reciprocal relationship between hyperglycemia and inflammation in the setting of diabetes mellitus has been the subject of extensive research. Insulin resistance, the hallmark of diabetic metabolic dysregulation, has been linked to the inflammatory cascade occurring mainly in adipose tissue. The main pathophysiologic processes facilitating the aforementioned interplay, is a phenotype switch of macrophages to the M1 class following gluco- and lipotoxicity and gut microbial remodeling. Given the correlation between inflammation and metabolic abnormalities, the elucidation of the exact mechanisms linking the two along with exploring the possible role of modulation of one in order to alter the other, could open up the possibility of novel therapeutic approaches for diabetes mellitus and its complications. Therefore, the aim of this review is to summarize the growing body of evidence concerning the molecular basis and results of pro-inflammatory processes in diabetic subjects along with the effect of current antidiabetic treatment options on tissue inflammation.

let-7a suppresses liver fibrosis via TGFβ/SMAD signaling transduction pathway

Liver fibrosis is the most common pathological outcome and the most severe complication of chronic liver diseases. Accumulating evidence suggests that miRNAs are involved in cell proliferation, differentiation, apoptosis, as well as the occurrence and development of various diseases. In this study, we found that the expression of let-7a was markedly decreased in the liver tissue samples and blood samples from patients with liver fibrosis compared with healthy volunteers. Furthermore, let-7a was downregulated in the liver tissues and blood samples in mouse models of liver fibrosis. Further analysis indicated that let-7a suppresses the activation level of hepatic stellate cells (HSCs). In addition, overexpression of let-7a reduced cell viability and promoted apoptosis of HSCs. Western blot analysis showed that let-7a might inhibit HSCs through TGFβ/SMAD signaling pathway. The present study provides a potential accurate target and vital evidence to better understand the underlying pathogenesis for early diagnosis and treatment of liver fibrosis.

Treatment with liraglutide, a glucagon-like peptide-1 analogue, improves effectively the skin lesions of psoriasis patients with type 2 diabetes: A prospective cohort study

BACKGROUND

It has been reported that GLP-1 analogue can improve the skin lesions of psoriasis. However further research is needed to confirm that finding.

OBJECTIVE

The study can provide further data regarding the efficacy and safety of GLP-1 analogue liraglutide in the treatment of psoriasis patients with type 2 diabetes.

METHODS

We recruit 7 psoriasis patients with type 2 diabetes, and use hypodermic injection with liraglutide1.8 mg. In 12 weeks of treatment, we estimate the difference of before and after respectively, likeBMI, waist circumference, fasting blood glucose, fasting C-peptide, HbA1c, blood lipid levels, CRP, PASI, DLQI, skin tissue and pathological analysis of psoriasis.

RESULTS

After 12 weeks of treatment, the mean value of PASI decreased from 15.7 ± 11.8 to 2.2 ± 3.0 (P = 0.03), while the DLQI decreased from 21.8 ± 6 to 4.1 ± 3.9 (P = 0.001). HbA1c was significantly improved after 12 weeks of treatment, decreased to 6.4 ± 0.8% (P = 0.04), the BMI decreased to 21 ± 3 kg m^-2 (P < 0.01), and the waist circumference was also significantly improved to 83 ± 1 cm (P < 0.05). And 12 weeks after, the fasting C-peptide levels increased to 1.9 ± 0.5 ng/ml (P = 0.006), HOMA - IR fell to 1.6 ± 0.6 (P = 0.03). Histological analysis showed a reduction in epidermal thickness after treatment. The mean PASI decreased from 15.7 (1.5-31.3) to 2.0 (0.3-8.7) (P = 0.03), the DLQI decreased from 22 (8-27) to 4 (0-10) (P = 0.001).

CONCLUSION

GLP-1 analogueliraglutide can improve the skin lesions of psoriasis patients with type 2 diabetes effectively, especially for extremely severe psoriasis patients. Its therapeutic effect may be related to anti-inflammatory, hypoglycemic and reducing weight.

The Effects of Hypoglycemic Agents on Non-alcoholic Fatty Liver Disease: Focused on Sodium-Glucose Cotransporter 2 Inhibitors and Glucagon-Like Peptide-1 Receptor Agonists

The only known, effective intervention for non-alcoholic fatty liver disease (NAFLD) is weight loss, and there is no approved pharmacotherapy. Recently, new hypoglycemic agents, such as sodium-glucose cotransporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 receptor agonists (GLP-1RAs), and their effects on NAFLD have received substantial interest. Herein, we review the currently available human studies regarding the effects of SGLT2 inhibitors and GLP-1RAs on NAFLD/non-alcoholic steatohepatitis in patients with type 2 diabetes mellitus, and we describe the possible mechanisms explaining the positive effects of these agents on NAFLD.

The role of macrophages in nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) and its inflammatory and often progressive subtype nonalcoholic steatohepatitis (NASH) are becoming the leading cause of liver-related morbidity and mortality worldwide, and a primary indication for liver transplantation. The pathophysiology of NASH is multifactorial and not yet completely understood; however, innate immunity is a major contributing factor in which liver-resident macrophages (Kupffer cells) and recruited macrophages play a central part in disease progression. In this Review, we assess the evidence for macrophage involvement in the development of steatosis, inflammation and fibrosis in NASH. In this process, not only the polarization of liver macrophages towards a pro-inflammatory phenotype is important, but adipose tissue macrophages, especially in the visceral compartment, also contribute to disease severity and insulin resistance. Macrophage activation is mediated by factors such as endotoxins and translocated bacteria owing to increased intestinal permeability, factors released from damaged or lipoapoptotic hepatocytes, as well as alterations in gut microbiota and defined nutritional components, including certain free fatty acids, cholesterol and their metabolites. Reflecting the important role of macrophages in NASH, we also review studies investigating drugs that target macrophage recruitment to the liver, macrophage polarization and their inflammatory effects as potential treatment options for patients with NASH.

Treating nonalcoholic steatohepatitis with antidiabetic drugs: Will GLP-1 agonists end the struggle?

Nonalcoholic fatty liver disease (NAFLD) is highly associated with insulin resistance (IR), type 2 diabetes mellitus and metabolic syndrome, being characterized as the hepatic component of metabolic syndrome. Despite its high prevalence, no pharmacological treatment has been established, as of yet. A growing body of evidence, however, shows that reducing IR can result in improvement of the biochemical and histological features of nonalcoholic steatohepatitis (NASH)-the aggressive form of NAFLD that can lead to cirrhosis and hepatocellular carcinoma. Unfortunately, the several trials that have assessed the effect of various antidiabetic agents to date have failed to establish an effective and safe treatment regimen for patients with NAFLD. Glucagon-like peptide-1 (commonly known as GLP-1) agonists are a novel class of antidiabetic drugs that improve insulin sensitivity and promote weight loss. They also appear to have a direct effect on the lipid metabolism of hepatocytes, reducing hepatic steatosis. Several trials have demonstrated that GLP-1 agonists can reduce aminotransferase levels and improve liver histology in patients with NAFLD, suggesting that these agents could serve as an alternative treatment option for these patients. This manuscript discusses the role and potential mechanisms of GLP-1 agonists in the treatment of NASH.

Pleiotropic Effects of GLP-1 and Analogs on Cell Signaling, Metabolism, and Function

The incretin hormone Glucagon-Like Peptide-1 (GLP-1) is best known for its "incretin effect" in restoring glucose homeostasis in diabetics, however, it is now apparent that it has a broader range of physiological effects in the body. Both in vitro and in vivo studies have demonstrated that GLP-1 mimetics alleviate endoplasmic reticulum stress, regulate autophagy, promote metabolic reprogramming, stimulate anti-inflammatory signaling, alter gene expression, and influence neuroprotective pathways. A substantial body of evidence has accumulated with respect to how GLP-1 and its analogs act to restore and maintain normal cellular functions. These findings have prompted several clinical trials which have reported GLP-1 analogs improve cardiac function, restore lung function and reduce mortality in patients with obstructive lung disease, influence blood pressure and lipid storage, and even prevent synaptic loss and neurodegeneration. Mechanistically, GLP-1 elicits its effects via acute elevation in cAMP levels, and subsequent protein kinase(s) activation, pathways well-defined in pancreatic β-cells which stimulate insulin secretion in conjunction with elevated Ca2+ and ATP. More recently, new studies have shed light on additional downstream pathways stimulated by chronic GLP-1 exposure, findings which have direct relevance to our understanding of the potential therapeutic effects of longer lasting analogs recently developed for clinical use. In this review, we provide a comprehensive description of the diverse roles for GLP-1 across multiple tissues, describe downstream pathways stimulated by acute and chronic exposure, and discuss novel pleiotropic applications of GLP-1 mimetics in the treatment of human disease.