Pioglitazone/Metformin

Combination of Pioglitazone and Metformin Actions on Liver Lipid Metabolism in Obese Mice

BACKGROUND

Despite the increasing prevalence rate of nonalcoholic fatty liver disease (NAFLD) worldwide, efficient pharmacotherapeutic regimens against NAFLD still need to be explored. Previous studies found that pioglitazone and metformin therapy could partly ameliorate NAFLD, but their combination therapy effects have not been researched. In the present study, we assessed the protective effects of metformin and pioglitazone combination therapy on liver lipid metabolism in high-fat diet (HFD)-fed mice and investigated the molecular mechanism.

METHODS

Male C57BL/6 mice were divided into five groups: normal control; HFD control; metformin monotherapy; pioglitazone monotherapy and combined therapy. After 8 weeks of pharmacological intervention, glucose and lipid metabolism characteristics, hepatic histology, lipidomics profiling and RNA-seq analysis were performed.

RESULTS

The combination of pioglitazone and metformin significantly ameliorated HFD-induced metabolic disturbance and the hepatic oil red O area. A lipidomics analysis showed that combined therapy could significantly reduce the high levels of free fatty acids (FFA), diacylglycerol and triglycerides, while a set of glycerophospholipids and sphingolipids were increased in the combined therapy group. Consistently, an RNA-seq analysis also showed a remarkable reduction in genes associated with FFA uptake and de novo lipogenesis, including Cd36, Fads1, Fads2, Fasn, Scd1, Elovl5 and Pklr in the combined therapy group.

CONCLUSIONS

Pioglitazone and metformin might have a synergistic protective effect on NAFLD by improving hepatic lipid profiles in HFD-induced mice. Further studies are needed to verify the clinical effects.

Potential benefits of metformin and pioglitazone combination therapy via gut microbiota and metabolites in high-fat diet-fed mice

Metformin and pioglitazone monotherapy have been proven to alter gut microbiota in diabetes and obesity. The present study aimed to investigated whether the combined administration of pioglitazone and metformin achieved superior protective effects on high-fat diet (HFD)-fed obese mice and elucidated its molecular mechanism via the gut microbiota and its metabolites. C57BL/6 males were randomly divided into five groups: the control group, fed a normal control diet; the HFD group, fed an HFD; the metformin monotherapy group, fed an HFD and treated with metformin; the pioglitazone monotherapy group, fed an HFD and treated with pioglitazone; and the combination therapy group, fed an HFD and treated with metformin and pioglitazone combination therapy. The cecal contents were collected for 16S rDNA amplicon sequencing and untargeted metabolomics analysis. The results showed that the combination therapy of metformin and pioglitazone significantly improved insulin sensitivity and glucolipid metabolism in HFD-fed mice. Combination therapy markedly altered gut microbiota by increasing beneficial bacteria, such as Bifidobacterium, Christensenellaceae_R-7_group, Faecalibacterium and Roseburia, and decreasing harmful bacteria, such as Oscillibacter and Eubacterium_xylanophilum_group. Fecal metabolites were significantly changed in the combination therapy group, including a reduction in amino acid metabolism and augmentation of lipid metabolism, such as citrulline, sarcosine, D-glutamine, lipoxin A4, prostaglandin E2, stearidonic acid and lucidenic acid A. These results revealed that combined metformin and pioglitazone therapy had synergistic effects or at least have an additive effect on modifying gut microbiota and metabolites, closely associated with improved glucolipid metabolic parameters in HFD-fed mice, which provides novel evidence and promising targets for metformin and pioglitazone combination therapy in type 2 diabetes.

Effects of Oral Glucose-Lowering Agents on Gut Microbiota and Microbial Metabolites

The current research and existing facts indicate that type 2 diabetes mellitus (T2DM) is characterized by gut microbiota dysbiosis and disturbed microbial metabolites. Oral glucose-lowering drugs are reported with pleiotropic beneficial effects, including not only a decrease in glucose level but also weight loss, antihypertension, anti-inflammation, and cardiovascular protection, but the underlying mechanisms are still not clear. Evidence can be found showing that oral glucose-lowering drugs might modify the gut microbiome and thereby alter gastrointestinal metabolites to improve host health. Although the connections among gut microbial communities, microbial metabolites, and T2DM are complex, figuring out how antidiabetic agents shape the gut microbiome is vital for optimizing the treatment, meaningful for the instruction for probiotic therapy and gut microbiota transplantation in T2DM. In this review, we focused on the literatures in gut microbiota and its metabolite profile alterations beneficial from oral antidiabetic drugs, trying to provide implications for future study in the developing field of these drugs, such as combination therapies, pre- and probiotics intervention in T2DM, and subjects with pregestational diabetes and gestational diabetes mellitus.

Racial ethnic differences in type 2 diabetes treatment patterns and glycaemic control in the Boston Area Community Health Survey

OBJECTIVES

Numerous studies continue to report poorer glycaemic control, and a higher incidence of diabetes-related complications among African-Americans and Hispanic-Americans as compared with non-Hispanic Caucasians with type 2 diabetes. We examined racial/ethnic differences in receipt of hypoglycaemic medications and glycaemic control in a highly insured Massachusetts community sample of individuals with type 2 diabetes.

SETTING

Community-based sample from Boston, Massachusetts, USA.

PARTICIPANTS

682 patients with physician-diagnosed diabetes from the third wave of the Boston Area Community Health Survey (2010-2012). The study included approximately equal proportions of African-Americans, Hispanics and Caucasians.

METHODS

We examined racial/ethnic disparities in diabetes treatment by comparing proportions of individuals on mutually exclusive diabetes treatment regimens across racial/ethnic subgroups. Using multivariable linear and logistic regression, we also examined associations between race/ethnicity and glycaemic control in the overall population, and within treatment regimens, adjusting for age, gender, income, education, health insurance, health literacy, disease duration, diet and physical activity.

RESULTS

Among those treated (82%), the most commonly prescribed antidiabetic regimens were biguanides only (31%), insulin only (23%), and biguanides and insulin (16%). No overall racial/ethnic differences in treatment or glycaemic control (per cent difference for African-Americans: 6.18, 95% CI -1.00 to 13.88; for Hispanic-Americans: 1.01, 95% CI -10.42 to 12.75) were observed. Within regimens, we did not observe poorer glycaemic control for African-Americans prescribed biguanides only, insulin only or biguanides combined with insulin/sulfonylureas. However, African-Americans prescribed miscellaneous regimens had higher risk of poorer glycaemic control (per cent difference=23.37, 95% CI 7.25 to 43.33). There were no associations between glycaemic levels and Hispanic ethnicity overall, or within treatment regimens.

CONCLUSIONS

Findings suggest a lack of racial/ethnic disparities in diabetes treatment patterns and glycaemic control in this highly insured Massachusetts study population. Future studies are needed to understand impacts of increasing insurance coverage on racial/ethnic disparities in treatment patterns and related outcomes.

Effect of addition of either sitagliptin or pioglitazone in patients with uncontrolled type 2 diabetes mellitus on metformin: A randomized controlled trial

OBJECTIVE

To compare and study the dipeptidy1 peptidase-4 (DPP-4) inhibitors in combination with metformin against established combination therapies.

MATERIALS AND METHODS

This 16-week study was designed to compare sitagliptin versus pioglitazone as add-on therapy in patients of type 2 diabetes mellitus inadequately controlled with metformin alone. Fifty-two patients were randomized into two groups to receive either sitagliptin 100 mg (group 1) or pioglitazone 30 mg (group 2) in addition to metformin. The primary efficacy end point was change in HbA1c. Secondary end points included change in fasting plasma glucose (FPG), body weight and lipid profile. Treatment satisfaction was assessed using the Diabetes Treatment Satisfaction Questionnaire. Both the groups had a significant decrease in HbA1c.

RESULTS

There was no significant difference between mean reductions in FPG in both the groups. There was a significant decrease in the mean body weight and body mass index in group 1 in contrast to the significant increase in the same in group 2. Both the treatment groups reported a significant decrease in High-density lipoprotein (HDL-C) and Triglyceride.

CONCLUSION

Sitagliptin was well tolerated without any incidence of hypoglycemia. It was concluded that sitagliptin as an add-on to metformin is as effective and well tolerated as pioglitazone.

Effects of a combination of sitagliptin plus metformin vs metformin monotherapy on glycemic control, β-cell function and insulin resistance in type 2 diabetic patients

AIMS

To evaluate the impact on glycemic control, insulin resistance, and insulin secretion of sitagliptin+metformin compared to metformin in type 2 diabetic patients.

METHODS

Patients were instructed to take metformin for 8 ± 2 months, then they were randomly assigned to sitaglipin 100 mg or placebo for 12 months. We evaluated at 3, 6, 9, and 12 months: body mass index (BMI), glycemic control, fasting plasma insulin (FPI), HOMA-IR, HOMA-β, fasting plasma proinsulin (FPPr), proinsulin/fasting plasma insulin ratio (Pr/FPI ratio), C-peptide, glucagon, adiponectin (ADN), and high sensitivity-C reactive protein (Hs-CRP). Before, and after 12 months since the addition of sitagliptin, patients underwent a combined euglycemic hyperinsulinemic and hyperglycemic clamp, with subsequent arginine stimulation.

RESULTS

Both treatments similarly decreased body weight, and BMI; on the other hand, they both improved glycemic control, glucagon and HOMA-IR, but sitagliptin+metformin were more effective in reducing these parameters. Sitagliptin+metformin, but not placebo+metformin, decreased FPPr, FPPR/FPI ratio, and increased C-peptide values, even if no differences between the groups were recorded. Sitaglitin+metformin gave also a greater increase of HOMA-β, M value, C-peptide response to arginine and disposition index compared to placebo+metformin group.

CONCLUSIONS

Other than improving glycemic control, sitagliptin+metformin also improved β-cell function better than metformin alone.

Vildagliptin added to metformin on β-cell function after a euglycemic hyperinsulinemic and hyperglycemic clamp in type 2 diabetes patients

BACKGROUND

This study evaluated the effect of vildagliptin + metformin on glycemic control and β-cell function in type 2 diabetes patients.

SUBJECTS AND METHODS

One hundred seventy-one type 2 diabetes patients, naive to antidiabetes therapy and with poor glycemic control, were instructed to take metformin for 8±2 months up to a mean dosage of 2,500±500 mg/day; then they were randomly assigned to add vildaglipin 50 mg twice a day or placebo for 12 months. We evaluated at 3, 6, 9, and 12 months: body mass index, glycemic control, fasting plasma insulin, homeostasis model assessment insulin resistance index (HOMA-IR), homeostasis model assessment β-cell function index (HOMA-β), fasting plasma proinsulin, proinsulin/fasting plasma insulin ratio, C-peptide, glucagon, adiponectin, and high-sensitivity C-reactive protein. Before and at 12 months after the addition of vildagliptin, patients underwent a combined euglycemic hyperinsulinemic and hyperglycemic clamp, with subsequent arginine stimulation, to assess insulin sensitivity and insulin secretion.

RESULTS

After 12 months of treatment, vildagliptin + metformin gave a better decrease of body weight, glycemic control, HOMA-IR, and glucagon and a better increase of HOMA-β compared with placebo + metformin. Regarding the measures of β-cell function, treatment-induced changes in M-value, first- and second-phase C-peptide response to glucose, and C-peptide response to arginine were significantly higher in the vildagliptin + metformin group compared with the placebo + metformin group.

CONCLUSION

The addition of vildagliptin to metformin gave a better improvement of glycemic control, insulin resistance, and β-cell function compared with metformin alone.

Achieving glycemic goal with initial versus sequential combination therapy using metformin and pioglitazone in type 2 diabetes mellitus

OBJECTIVE

To compare glycemic goal achievement (HbA(1c) < 7%) in type 2 diabetes patients receiving initial metformin plus pioglitazone combination therapy and initial metformin monotherapy augmented with pioglitazone in a cohort follow-up study.

RESEARCH DESIGN AND METHODS

Adult patients were identified from the Ingenix Impact database (01/01/99-03/31/07). Qualified patients had a baseline HbA(1c) ≥ 7%; a second laboratory value within 9 months; no other anti-diabetic prescriptions 6 months before or 30 days after treatment initiation; and continuous enrollment during baseline. The index date was the date on which the second medication was initiated. Goal achievement was compared independently at 6, 12 and 18 months using a chi-square test. Logistic regression was used to control for baseline differences. Last observation carried forward was used to impute missing HbA(1c) values. Sub-group analysis was conducted on patients with baseline HbA(1c) values between 7% and 9%, and >9%.

MAIN OUTCOME MEASURES

The proportion of patients achieving glycemic goal at each specified time point.

RESULTS

A total of 179 patients received initial combination therapy and 347 patients received sequential therapy. A greater proportion of initial combination patients achieved the glycemic goal compared to sequential patients at months 6, 12 and 18 (66.5 vs. 49.6%; 65.9 vs. 48.1%; 65.9 vs. 48.4%, respectively; p < 0.001 for all). Logistic regression confirmed these findings (odds ratios [OR]: 3.18-3.31). Sub-group analysis showed a more pronounced advantage for aggressive initial combination treatment among patients with HbA(1c) > 9% (OR: 5.39-6.04) than among patients with HbA(1c) between 7% and 9% (OR: 2.28-2.79).

CONCLUSIONS

Initial combination therapy patients are more likely to achieve glycemic control than sequential therapy patients, especially for patients with baseline HbA(1c) > 9%. This study is limited by the relatively small sample size and the frequency of HbA(1c) reporting. Future research could examine goal achievement using a larger sample and more complete laboratory data to confirm these findings.

Effects of sitagliptin or metformin added to pioglitazone monotherapy in poorly controlled type 2 diabetes mellitus patients

The aim of the study was to compare the effects of the addition of sitagliptin or metformin to pioglitazone monotherapy in poorly controlled type 2 diabetes mellitus patients on body weight, glycemic control, beta-cell function, insulin resistance, and inflammatory state parameters. One hundred fifty-one patients with uncontrolled type 2 diabetes mellitus (glycated hemoglobin [HbA(1c)] >7.5%) in therapy with pioglitazone 30 mg/d were enrolled in this study. We randomized patients to take pioglitazone 30 mg plus sitagliptin 100 mg once a day, or pioglitazone 15 mg plus metformin 850 mg twice a day. We evaluated at baseline and after 3, 6, 9, and 12 months these parameters: body weight, body mass index, HbA(1c), fasting plasma glucose (FPG), postprandial plasma glucose (PPG), fasting plasma insulin (FPI), homeostasis model assessment insulin resistance index (HOMA-IR), homeostasis model assessment beta-cell function index, fasting plasma proinsulin (Pr), Pr/FPI ratio, adiponectin, resistin (R), tumor necrosis factor-alpha (TNF-alpha), and high-sensitivity C-reactive protein. A decrease of body weight and body mass index was observed with metformin, but not with sitagliptin, at the end of the study. We observed a comparable significant decrease of HbA(1c), FPG, and PPG and a significant increase of homeostasis model assessment beta-cell function index compared with baseline in both groups without any significant differences between the 2 groups. Fasting plasma insulin, fasting plasma Pr, Pr/FPI ratio, and HOMA-IR values were decreased in both groups even if the values obtained with metformin were significantly lower than the values obtained with sitagliptin. There were no significant variations of ADN, R, or TNF-alpha with sitagliptin, whereas a significant increase of ADN and a significant decrease of R and TNF-alpha values were recorded with metformin. A significant decrease of high-sensitivity C-reactive protein value was obtained in both groups without any significant differences between the 2 groups. There was a significant correlation between HOMA-IR decrease and ADN increase, and between HOMA-IR decrease and R and TNF-alpha decrease in pioglitazone plus metformin group after the treatment. The addition of both sitagliptin or metformin to pioglitazone gave an improvement of HbA(1c), FPG, and PPG; but metformin led also to a decrease of body weight and to a faster and better improvement of insulin resistance and inflammatory state parameters, even if sitagliptin produced a better protection of beta-cell function.

Oral combination therapy: repaglinide plus metformin for treatment of type 2 diabetes

Type 2 diabetes is characterized by decreases in insulin secretion and insulin sensitivity. Several classes of oral antidiabetic medications are currently approved for the treatment of type 2 diabetes. A stepwise treatment approach from monotherapy to combination therapy is traditionally used; however, the frequency of treatment failure with monotherapy has resulted in a move towards earlier treatment with combination therapies that target the two principal defects in glycaemic control. One such combination regimen is repaglinide (a prandial glucose regulator that increases insulin release) plus metformin (an insulin sensitizer that inhibits hepatic glucose output, increases peripheral glucose uptake and utilization and minimizes weight gain). Findings from several clinical trials have shown that combination therapy with repaglinide plus metformin is well tolerated and results in greater reductions of haemoglobin A(1c) and fasting plasma glucose values compared with either monotherapy. Repaglinide may also provide a more suitable alternative to combination therapy with sulphonylureas and metformin because of its reduced propensity for hypoglycaemia. The combination regimen of repaglinide plus metformin should therefore be considered as a valuable option in the management of patients with type 2 diabetes when monotherapy is no longer adequate.

Effect of initial combination therapy with sitagliptin, a dipeptidyl peptidase-4 inhibitor, and metformin on glycemic control in patients with type 2 diabetes

OBJECTIVE

To assess the efficacy and safety of initial combination therapy with sitagliptin and metformin in patients with type 2 diabetes and inadequate glycemic control on diet and exercise.

RESEARCH DESIGN AND METHODS

In a 24-week, randomized, double-blind, placebo-controlled, parallel-group study, 1,091 patients with type 2 diabetes and A1C 7.5-11% were randomized to one of six daily treatments: sitagliptin 100 mg/metformin 1,000 mg (S100/M1000 group), sitagliptin 100 mg/metformin 2,000 mg (S100/M2000 group), metformin 1,000 mg (M1000 group), metformin 2,000 mg (M2000 group) (all as divided doses administered twice daily [b.i.d.]), sitagliptin 100 mg q.d. (S100 group), or placebo. Patients who had an A1C >11% or a fasting glucose value >280 mg/dl after the run-in period were not eligible to be randomized; these patients could participate in an open-label substudy and were treated with S100/M2000 for 24 weeks.

RESULTS

The mean baseline A1C was 8.8% in the randomized patients. The placebo-subtracted A1C change from baseline was -2.07% (S100/M2000), -1.57% (S100/M1000), -1.30% (M2000), -0.99% (M1000), and -0.83% (S100) (P < 0.001 for comparisons versus placebo and for coadministration versus respective monotherapies). The proportion of patients achieving an A1C <7% and <6.5% was 66 and 44%, respectively, in the S100/M2000 group (P < 0.001 vs. S100 or M2000). For the open-label cohort (n = 117; baseline A1C 11.2%) treated with S100/M2000, the within-group mean A1C change from baseline was -2.9%. The incidence of hypoglycemia was low (0.5-2.2%) across active treatment groups and not significantly different from that in the placebo group (0.6%). The incidence of gastrointestinal adverse experiences was similar for coadministration therapies compared with their respective metformin monotherapy.

CONCLUSIONS

The initial combination of sitagliptin and metformin provided substantial and additive glycemic improvement and was generally well tolerated in patients with type 2 diabetes.