ADOPT: lessons from comparison of glycemic durability of rosiglitazone, metformin, or glyburide monotherapy

Improved glycemic and weight control with Dulaglutide addition in SGLT2 inhibitor treated obese type 2 diabetic patients at high cardiovascular risk in a real-world setting. The AWARE-2 study

We evaluated the effects on glycemic control and body weight of a GLP1-RA in obese type 2 diabetic patients treated with SGLT2-inhibitors and other hypoglycemic agents and/or insulin, in a real-world setting. A cohort of 583 type 2 diabetic outpatients treated with a SGLT2 inhibitor and/or other anti-diabetic medications were examined. Because patients had suboptimal glycemic control, the GLP1-RA Dulaglutide was added to ongoing medications. At 6 months, 334 patients had a follow-up visit. Patients were classified in terms of cardiovascular risk (CVR) employing the ESC-EASD 2019 criteria, with the AWARE app. The study's primary endpoints were changes in: 1) HbA1c level, 2) BMI, and 3) body weight after six months of treatment. Secondary endpoints were evaluation of Dulaglutide addition in type 2 diabetic patients: 1) with more or less than ten years of T2DM; 2) more or less than 75 years of age and in different subgroups of CVR. In the 334 patients which had a 6 months follow-up visit, age was 65,9+9,8; 33.5 % (112) were females and 66.5 % (222) were males. After six months of Dulaglutide treatment, we found a significant reduction in HbA1c levels (8.0+10.5 mmol/mol; p<0.0001) and in body mass index (1.1+1.1 kg/m2; p<0.0001). Efficacy of Dulaglutide was not affected by different CVD risk categories, age and T2DM duration. This real world study provides evidence for significant reductions in HbA1c level, body mass index and body weight in obese type 2 diabetic patients who received add-on treatment with the weekly GLP-1RA, Dulaglutide.

Metformin improves blood glucose by increasing incretins independent of changes in gluconeogenesis in youth with type 2 diabetes

AIMS/HYPOTHESIS

Metformin is the only approved oral agent for youth with type 2 diabetes but its mechanism of action remains controversial. Recent data in adults suggest a primary role for the enteroinsular pathway, but there are no data in youth, in whom metformin efficacy is only ~50%. Our objectives were to compare incretin concentrations and rates of glucose production and gluconeogenesis in youth with type 2 diabetes before and after short-term metformin therapy compared with peers with normal glucose tolerance (NGT).

METHODS

This is a case-control observational study in youth with type 2 diabetes who were not on metformin (n = 18) compared with youth with NGT (n = 10) who were evaluated with a 2 day protocol. A 75 g OGTT was administered to measure intact glucagon-like 1 peptide (iGLP-1), gastric inhibitory polypeptide (GIP) and peptide YY (PYY). Insulinogenic index (IGI) and whole-body insulin sensitivity were calculated using glucose and insulin levels from the OGTT. Basal rates of gluconeogenesis (²H₂O), glucose production ([6,6-²H₂]glucose) and whole-body lipolysis ([²H₅]glycerol) were measured after an overnight fast on study day 2. Youth with type 2 diabetes (n = 9) were subsequently evaluated with an identical 2 day protocol after 3 months on the metformin study.

RESULTS

Compared with individuals with NGT, those with type 2 diabetes had higher fasting (7.8 ± 2.5 vs 5.1 ± 0.3 mmol/l, mean ± SD p = 0.002) and 2 h glucose concentrations (13.8 ± 4.5 vs 5.9 ± 0.9 mmol/l, p = 0.001), higher rates of absolute gluconeogenesis (10.0 ± 1.7 vs 7.2 ± 1.1 μmol [kg fat-free mass (FFM)]^-1 min^-1, p < 0.001) and whole-body lipolysis (5.2 ± 0.9 vs 4.0 ± 1.4 μmol kg_FFM^-1 min^-1, p < 0.01), but lower fasting iGLP-1 concentrations (0.5 ± 0.5 vs 1.3 ± 0.7 pmol/l, p < 0.01). Metformin decreased 2 h glucose (pre metformin 11.4 ± 2.8 vs post metformin 9.9 ± 1.9 mmol/l, p = 0.04) and was associated with ~20-50% increase in IGI (median [25th-75th percentile] pre 1.39 [0.89-1.47] vs post 1.43 [0.88-2.70], p = 0.04), fasting iGLP-1 (pre 0.3 ± 0.2 vs post 1.0 ± 0.7 pmol/l, p = 0.02), 2 h iGLP (pre 0.4 ± 0.2 vs post 1.2 ± 0.9 pmol/l, p = 0.06), fasting PYY (pre 6.3 ± 2.2 vs post 10.5 ± 4.3 pmol/l, p < 0.01) and 2 h PYY (pre 6.6 ± 2.9 vs post 9.0 ± 4.0 pmol/l, p < 0.01). There was no change in BMI, insulin sensitivity or GIP concentrations pre vs post metformin. There were no differences pre vs post metformin in rates of glucose production (15.0 ± 3.9 vs 14.9 ± 2.2 μmol kg_FFM^-1 min^-1, p = 0.84), absolute gluconeogenesis (9.9 ± 1.8 vs 9.7 ± 1.7 μmol kg_FFM^-1 min^-1, p = 0.76) or whole-body lipolysis (5.0 ± 0.7 vs 5.3 ± 1.3 μmol kg_FFM^-1 min^-1, p = 0.20). Post metformin iGLP-1 and PYY concentrations in youth with type 2 diabetes were comparable to levels in youth with NGT.

CONCLUSIONS/INTERPRETATION

Overall, the improved postprandial blood glucose levels and increase in incretins observed in the absence of changes in insulin sensitivity and gluconeogenesis, support an enteroinsular mechanistic pathway in youth with type 2 diabetes treated with short-term metformin.

Exenatide regulates pancreatic islet integrity and insulin sensitivity in the nonhuman primate baboon Papio hamadryas

The glucagon-like peptide-1 receptor agonist exenatide improves glycemic control by several and not completely understood mechanisms. Herein, we examined the effects of chronic intravenous exenatide infusion on insulin sensitivity, β cell and α cell function and relative volumes, and islet cell apoptosis and replication in nondiabetic nonhuman primates (baboons). At baseline, baboons received a 2-step hyperglycemic clamp followed by an l-arginine bolus (HC/A). After HC/A, baboons underwent a partial pancreatectomy (tail removal) and received a continuous exenatide (n = 12) or saline (n = 12) infusion for 13 weeks. At the end of treatment, HC/A was repeated, and the remnant pancreas (head-body) was harvested. Insulin sensitivity increased dramatically after exenatide treatment and was accompanied by a decrease in insulin and C-peptide secretion, while the insulin secretion/insulin resistance (disposition) index increased by about 2-fold. β, α, and δ cell relative volumes in exenatide-treated baboons were significantly increased compared with saline-treated controls, primarily as the result of increased islet cell replication. Features of cellular stress and secretory dysfunction were present in islets of saline-treated baboons and absent in islets of exenatide-treated baboons. In conclusion, chronic administration of exenatide exerts proliferative and cytoprotective effects on β, α, and δ cells and produces a robust increase in insulin sensitivity in nonhuman primates.

Effect of Gangjihwan on hepatic steatosis and inflammation in high fat diet-fed mice

ETHNOPHARMACOLOGICAL RELEVANCE

Gangjihwan (DF), a polyherbal drug composed of Ephedra intermedia Schrenk et C. A. Mayer (Ephedraceae), Lithospermum erythrorhizon Siebold et Zuccarini (Borraginaceae), and Rheum palmatum L. (Polygonaceae), is used to treat obesity in local Korean clinics. The constituents of DF have traditionally been reported to exert anti-obesity and anti-nonalcoholic fatty liver disease (NAFLD) effects. Thus, we investigated the effects of DF on obesity and NAFLD and the underlying mechanisms.

MATERIALS AND METHODS

DF was extracted with water (DF-FW), 30% ethyl alcohol (DF-GA30), or 70% ethyl alcohol (DF-GA70). The chemical profile of DF was monitored using high performance liquid chromatography (HPLC)-ultraviolet analysis. The effects of DF on indices of obesity and NAFLD in high fat diet (HFD)-fed C57BL/6J mice and HepG2 cells were examined using quantitative real-time polymerase chain reaction, Oil red O staining, hematoxylin-eosin staining, toluidine blue staining, and immunohistochemistry.

RESULTS

The presence of ephedrine, pseudoephedrine, aloe-emodin, and emodin in DF was determined by 3D chromatography using HPLC. Administration of DF-GA70 to HFD-fed obese mice decreased body weight, epididymal adipose tissue mass, and epididymal adipocyte size. DF-GA70 reduced serum levels of free fatty acids and triglycerides. All three DF extracts lowered serum alanine transaminase levels, hepatic lipid accumulation, and infiltration of macrophages, with the largest effects observed for DF-GA70. DF-GA70 increased mRNA levels of fatty acid oxidation genes and decreased mRNA levels of genes for lipogenesis and inflammation in the liver of obese mice. Treatment of HepG2 cells with a mixture of oleic acid and palmitoleic acid induced significant lipid accumulation, whereas all three DF extracts inhibited lipid accumulation. DF-GA70 also altered the expression of lipolytic and lipogenic genes in HepG2 cells.

CONCLUSIONS

These results indicate that DF inhibits obesity and obesity-induced severe hepatic steatosis and inflammation without any adverse effects and that these effects may be mediated by regulation of the hepatic expression of lipid metabolism and inflammatory genes. These findings suggest that DF is a safe and efficient anti-obesity and anti-nonalcoholic steatohepatosis drug.

The effects of herbal composition Gambigyeongsinhwan (4) on hepatic steatosis and inflammation in Otsuka Long-Evans Tokushima fatty rats and HepG2 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Hepatic steatosis has risen rapidly in parallel with a dramatic increase in obesity. The aim of this study was to determine whether the herbal composition Gambigyeongsinhwan (4) (GGH(4)), composed of Curcuma longa L. (Zingiberaceae), Alnus japonica (Thunb.) Steud. (Betulaceae), and the fermented traditional Korean medicine Massa Medicata Fermentata, regulates hepatic steatosis and inflammation.

MATERIALS AND METHODS

The effects of GGH(4) on hepatic steatosis and inflammation in Otsuka Long-Evans Tokushima fatty (OLETF) rats and HepG2 cells were examined using Oil red O, hematoxylin and eosin, and toluidine blue staining, immunohistochemistry, quantitative real-time polymerase chain reaction, and peroxisome proliferator-activated receptor α (PPARα) transactivation assay.

RESULTS

Administration of GGH(4) to OLETF rats improved hepatic steatosis and lowered serum levels of alanine transaminase, total cholesterol, triglycerides, and free fatty acids. GGH(4) increased mRNA levels of fatty acid oxidation enzymes (ACOX, HD, CPT-1, and MCAD) and decreased mRNA levels of lipogenesis genes (FAS, ACC1, C/EBPα, and SREBP-1c) in the liver of OLETF rats. In addition, infiltration of inflammatory cells and expression of inflammatory cytokines (CD68, TNFα, and MCP-1) in liver tissue were reduced by GGH(4). Treatment of HepG2 cells with a mixture of oleic acid and palmitoleic acid induced significant lipid accumulation, but GGH(4) inhibited lipid accumulation by regulating the expression of hepatic fatty acid oxidation and lipogenic genes. GGH(4) also increased PPARα reporter gene expression. These effects of GGH(4) were similar to those of the PPARα activator fenofibrate, whereas the PPARα antagonist GW6471 reversed the inhibitory effects of GGH(4) on lipid accumulation in HepG2 cells.

CONCLUSIONS

These results suggest that GGH(4) inhibits obesity-induced hepatic steatosis and that this process may be mediated by regulation of the expression of PPARα target genes and lipogenic genes. GGH(4) also suppressed obesity-related hepatic inflammation. Thus, GGH(4) may be a promising drug for the treatment of obesity-related liver diseases.

PPARγ Agonist Rosiglitazone Suppresses Renal mPGES-1/PGE2 Pathway in db/db Mice

Evidence had shown the detrimental effect of prostaglandin (PG) E2 in diabetic nephropathy (DN) of STZ-induced type-1 diabetes but its role in the development of DN of type-2 diabetes remains uncertain. The present study was undertaken to investigate the regulation of PGE2 synthetic pathway and the interaction between peroxisome proliferator-activated receptor (PPAR) γ and PGE2 synthesis in the kidneys of db/db mice. Strikingly, urinary PGE2 was remarkably elevated in db/db mice paralleled with the increased protein expressions of COX-2 and mPGES-1. In contrast, the protein expressions of COX-1, mPGES-2, cPGES, and 15-hydroxyprostaglandin dehydrogenase (15-PGDH) were not altered. Following 1-week rosiglitazone (Rosi) therapy, urinary PGE2, but not other prostanoids, was reduced by 57% in parallel with significant reduction of mPGES-1 protein and EP4 mRNA expressions. By immunohistochemistry, mPGES-1 was significantly induced in the glomeruli of db/db mice, which was almost entirely abolished by Rosi. In line with the reduction of glomerular mPGES-1, the glomerular injury score showed a tendency of improvement after 1 week of Rosi therapy. Collectively, the present study demonstrated an inhibitory effect of PPAR γ activation on renal mPGES-1/PGE2/EP4 pathway in type-2 diabetes and suggested that mPGES-1 may potentially serve as a therapeutic target for treating type-2 diabetes-associated DN.