Review on the effect of glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors for the treatment of non-alcoholic fatty liver disease

Activation of pCREB/Nrf-2 signaling mediates re-positioning of liraglutide as hepato-protective for methotrexate -induced liver injury (MILI)

Methotrexate (MTX) is commonly used to treat several types of cancer and autoimmune diseases. However, there is increasing concern over its organs toxicities particularly liver toxicity. Liraglutide, a glucagon like peptide-1 agonist, possesses antioxidant and anti-inflammatory features. This study aimed to explore the potential protective effect of liraglutide pre-treatment in ameliorating MTX-induced hepatotoxicity and to further investigate the underlying mechanisms. Rats received 1.2 mg/kg liraglutide intraperitoneal twice daily for 7 days before MTX. Results revealed that liraglutide significantly decreased activities of liver enzymes and oxidative stress in hepatocytes. Furthermore, NF-kB expression and related inflammatory markers (TNF-α, COX-2 and IL-6) were reduced in the pre-treatment group of liraglutide. These data validate the advantageous effects of liraglutide in MTX hepatotoxic animals. In addition, liraglutide increased the expression of the antioxidant transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf-2), along with the transcription of downstream phosphorylated cAMP response element-binding protein (pCREB) which increases the activity of Nrf-2. Additionally, caspase-3 expression/activity and BAX/Bcl-2 ratio were decreased following liraglutide pre-treatment. In conclusion, it was confirmed that liraglutide enhanced the antioxidant activity of liver cells by activating the Nrf-2 and pCREB signaling, thereby, reducing liver cell inflammation and apoptosis induced by MTX.

Gut microbiota, hypertension and chronic kidney disease: Recent advances

A large number of different microbial species populates intestine. Extensive research has studied the entire microbial population and their genes (microbiome) by using metagenomics, metatranscriptomics and metabolomic analysis. Studies suggest that the imbalances of the microbial community causes alterations in the intestinal homeostasis, leading to repercussions on other systems: metabolic, nervous, cardiovascular, immune. These studies have also shown that alterations in the structure and function of the gut microbiota play a key role in the pathogenesis and complications of Hypertension (HTN) and Chronic Kidney Disease (CKD). Increased blood pressure (BP) and CKD are two leading risk factors for cardiovascular disease and their treatment represents a challenge for the clinicians. In this Review, we discuss mechanisms whereby gut microbiota (GM) and its metabolites act on downstream cellular targets to contribute to the pathogenesis of HTN and CKD, and potential therapeutic implications.

Sitagliptin, a dipeptidyl peptidase-4 inhibitor, suppresses CXCL5 and SDF-1 and does not accelerate intestinal neoplasia formation in ApcMin/+ mice fed a high-fat diet

The relationship between type 2 diabetes mellitus and intestinal neoplasia has been shown epidemiologically. A high-fat diet (HFD) is also known to promote insulin resistance, which is a risk factor for intestinal neoplasia. Dipeptidyl peptidase-4 (DPP-4) inhibitors are used in the clinic for the treatment of type 2 diabetes and also to prolong the effects of glucagon-like peptide-1 (GLP-1). However, since the intestinotrophic hormone GLP-2 and chemokines, such as CXCL5 and stromal cell-derived factor-1 (SDF-1), are also substrates of DPP-4, DPP-4 inhibitors may increase the risk of intestinal carcinogenesis. In this study, we evaluated the impact of a DPP-4 inhibitor on intestinal tumorigenesis in Apc^Min/+ mice fed a HFD. Six-week-old male Apc^Min/+ mice were randomized to either a normal diet (10 kcal% fat) group, a HFD (60 kcal% fat) group, or a HFD group treated with sitagliptin (STG). The mice were euthanized nine weeks after the start of treatment. Daily treatment with STG did not increase number of intestinal tumors in the HFD group; however, this increase was not statistically significant. The mucosal concentration of total GLP-2 was significantly increased in the HFD group. The chemokine protein array showed elevated plasma concentrations of CXCL5 and SDF-1 in the HFD group. The administration of STG significantly suppressed the levels of plasma CXCL5 and SDF-1 in mice fed a HFD. Since CXCL5 expression is increased in patients with type 2 diabetes, and GLP-2, CXCL5 and SDF-1 are associated with tumor progression, DPP-4 inhibition may have potential as an agent for decreasing the risk of cancer in obese or diabetic patients.

Vildagliptin ameliorates biochemical, metabolic and fatty changes associated with non alcoholic fatty liver disease

Objective:

To determine the effect of Vildagliptin in non-alcoholic, fatty liver disease patients with dyslipidemia.

Methods:

A randomized placebo controlled trial was conducted at outpatient clinic of Medical Unit-I of Sheikh Zayed Medical College/Hospital, Rahim Yar Khan, in which fifty eight patients of NAFLD with dyslipidemia were divided in to two, case and control groups. The case group was given tablet Vildagliptin 50mg twice a day for twelve weeks and control group was given placebo in same way. Body weight, body mass index (BMI), lipid profile, liver enzymes and ultrasound finding of fatty liver were assayed before and after treatment.

Results:

After 12 weeks treatment of vildagliptin there was significant improvement in following parameters. Body weight and BMI decreased significantly from 88 ± 11 to79 ± 12 kg (p0.036) and 30±4to 27±5 kg/m² (p 0.005) respectively. Notable reduction in the value of TC, TG and LDL-C (TC:252±24 to 220±20mg/dl (p 0.031); TG: 190±24 to115±22 mg/dl (p 0.005); LDL-C 160±15 to 145±13mg/dl (p 0.004). HDL-C level increased significantly from 29±5to45±4 mg/dl (p 0.001). There was remarkable reduction in aminotransferases level (ALT: 78± 17 to 48±14IU/L (p 0.036). AST: 63.3±13 to41±11IU/L (p 0.002). There was overall 65.5% improvement in fatty liver grading on ultrasound with vildagliptin while non significant effects were seen in placebo group in all of the above parameters.

Conclusion:

Vildagliptin exhibited beneficial effects in non-alcoholic fatty liver disease, Non-diabetic patients with dyslipidemia.