Low-dose Metformin Research Articles

Vitamin B12 Deficiency in Diabetic Patients on Chronic Metformin Therapy

Introduction: Since its approval and universal acknowledgement in the 1990's as a first line agent for the treatment of Diabetes Mellitus Type II, studies have shown vitamin B12 deficiency to be a complication of chronic metformin therapy. Despite this awareness and few studies aimed at the general population, a systematic assessment of the prevalence of vitamin B12 deficiency in Type II diabetics on metformin in the veteran population has not been performed. Methods: A retrospective data analysis at a VA Hospital from 2002-2012 was performed which included 3844 diabetic patients on metformin who had B12 levels drawn while on metformin. Vitamin B12 deficiency was defined as B12 ≤ 218 pg/mL and further subdivided into moderate (218-175 pg/mL) and severe (1500 mg/day). The duration of metformin therapy was categorized as short (4 years) and long (>4 years). Results: Overall prevalence of B12 deficiency while on metformin therapy was 9.8 %. Only 38 % of the patients had baseline B12 levels checked prior to their becoming deficient. There was a significant difference when comparing B12 deficiency between control vs. metformin group (P < 0.0001 CI (2.5-10.6), OR 5.1, and Metformin vs. Insulin group P < 0.0001, CI (0.13-1.43), OR 11.6 (Table 1). There was a significant difference between short duration vs. long duration of metformin in regards to moderate vs. severe B12 deficiency (Table 2). In addition, there was a significant difference between low dose metformin group and high dose metformin group in regards to moderate vs. severe B12 deficiency (Table 2).Table 1: P value, Confidence Interval, and OR for Control vs. Metformin vs. Insulin.Table 2: Comparison of Duration and Dosing of Metformin therapy vs. B12 deficiencyConclusion: We report 9.8% overall prevalence of patients with B12 deficiency while on metformin. Compared to insulin-treated diabetics and non-diabetics, metformin group had significantly more patients with overt B12 deficiency (B12 < 218 pg/mL). Higher dose and longer duration appear to worsen the problem. B12 deficiency develops gradually and is frequently overlooked although it is easy to treat if suspected and managed in time. Our study highlights the lack of awareness of this important problem as evidenced by the small percentage of veterans that had undergone prior B12 testing (38%). Primary care providers and specialists need to be cognizant of the necessity of Vitamin B12 testing with chronic metformin therapy.

Probiotic B420 and prebiotic polydextrose improve efficacy of antidiabetic drugs in mice.

BackgroundGut microbiota is now known to control glucose metabolism. Previous studies have shown that probiotics and prebiotics may improve glucose metabolism, but their effects have not been studied in combination with drug therapy. The aim of this study was to investigate whether probiotics and prebiotics combined with drug therapy affect diabetic outcomes.MethodsTwo different study designs were used to test gut microbiota modulating treatments with metformin (MET) or sitagliptin (SITA) in male C57Bl/6J mice. In Design 1, diabetes was induced with four-week feeding with a ketogenic, 72 kcal% fat diet with virtually no carbohydrates. Mice were then randomly divided into four groups (n = 10 in each group): (1) vehicle, (2) Bifidobacterium animalis ssp. lactis 420 (B420) (109 CFU/day), (3) MET (2 mg/mL in drinking water), or (4) MET + B420 (same doses as in the MET and B420 groups). After another 4 weeks, glucose metabolism was assessed with a glucose tolerance test. Fasting glucose, fasting insulin and HOMA-IR were also assessed. In Design 2, mice were fed the same 72 kcal% fat diet to induce diabetes, but they were simultaneously treated within their respective groups (n = 8 in each group): (1) non-diabetic healthy control, (2) vehicle, (3) SITA [3 mg/(kg*day)] (4) SITA with prebiotic polydextrose (PDX) (0.25 g/day), (5) SITA with B420 (109 CFU/day), and (6) SITA + PDX + B420. Glucose metabolism was assessed at 4 weeks, and weight development was monitored for 6 weeks.ResultsIn Design 1, with low-dose metformin, mice treated with B420 had a significantly lower glycemic response (area under the curve) (factorial experiment, P = 0.002) and plasma glucose concentration (P = 0.02) compared to mice not treated with B420. In Design 2, SITA + PDX reduced glycaemia in the oral glucose tolerance test significantly more than SITA only (area under the curve reduced 28 %, P < 0.0001). In addition, B420, PDX or B420+PDX, together with SITA, further decreased fasting glucose concentrations compared to SITA only (−19.5, −40 and −49 %, respectively, P < 0.01 for each comparison). The effect of PDX may be due to its ability to increase portal vein GLP-1 concentrations together with SITA (P = 0.0001 compared to vehicle) whereas SITA alone had no statistically significant effect compared to vehicle (P = 0.14).ConclusionsThis study proposes that combining probiotics and/or prebiotics with antidiabetic drugs improves glycemic control and insulin sensitivity in mice. Mechanisms could be related to incretin secretion.Electronic supplementary materialThe online version of this article (doi:10.1186/s13098-015-0075-7) contains supplementary material, which is available to authorized users.

Treatment with metformin and a dipeptidyl peptidase-4 inhibitor elevates apelin levels in patients with type 2 diabetes mellitus.

BackgroundThe objective of this study was to assess the effects of metformin monotherapy or combined treatment with a dipeptidyl peptidase-4 inhibitor (vildagliptin) on apelin levels in patients with type 2 diabetes mellitus.MethodsTwenty-five patients with poor glycemic control (glycosylated hemoglobin >6.5% [48 mmol/mol]) taking 1,000 mg of metformin daily and 25 healthy controls matched for age and body mass index were enrolled in this study. Anthropometric parameters, glycemic and lipid profile, insulin resistance (homeostasis model assessment of insulin resistance index), and apelin levels were measured at baseline and at 12-week and 24-week visits.ResultsAt baseline, apelin levels were higher in the T2DM patients than in the controls (1.93±1.81 ng/mL versus 6.09±4.90 ng/mL; P<0.05). After 12 weeks, when vildagliptin was added, fasting blood glucose and glycosylated hemoglobin decreased, and apelin levels increased further (from 6.09±4.90 ng/mL to 24.23±12.59 ng/mL; P<0.05). Follow-up at 24 weeks showed no further improvement in the glycemic profile and no further increase in apelin levels.ConclusionBoth metformin and vildagliptin favorably changed glycemic indices and apelin levels. For patients inadequately controlled on a low dose of metformin, addition of vildagliptin may be helpful.

Abstract LB-264: Effects of dietary metformin/pioglitazone on lung adenoma formation in A/J mice

Abstract Introduction: Metabolomics and cancer chemoprevention are important contemporary concepts in cancer prevention and gaining traction as potential clinical trial topics. Our group has worked with type II diabetes agents clinically in oral cancer prevention and clinically and preclinically in both lung and head and neck cancer. Both pioglitazone and metformin are type II diabetes agents, and both drugs have promising epidemiologic evidence for efficacy as solid tumor prevention agents. They are well tolerated clinically for many years in millions of patients worldwide with acceptable toxicity profiles. We hypothesize these agents would be suitable in the chemoprevention setting and tested this hypothesis in experimental lung carcinogenesis in a benzo[a]pyrene (B[a]P) mouse model. Materials and Methods: We utilized 224 seven week old female A/J mice. All groups received 3 weekly doses of B[a]P by oral intubation and were randomized into 8 groups of 27 mice per group based on weights. Experimental diets were started one week after the last dose of B[a]P. Metformin (12 mg/g and 10.2 mg/g) and/or pioglitazone (0.18mg/g) were administered in the diet for 18 weeks, whereas late stage inhibition diets were started at 8 weeks post carcinogen. Animals were continued on the feeding schedule, weighed weekly, and monitored for weight loss, behavior changes, rough hair coat, or other signs of ill health. Results: The average number of adenomas per animal was 17.44 +/- 1.39 (SEM) in the control group. At the early stage intervention the average number of adenomas was 5.00 +/- 0.69 (P&amp;lt;0.0001) in the highest dose of metformin, 6.15 +/- 0.57 (P&amp;lt;0.0001) for the low dose metformin, and 11.92 +/-1.00 (P = 0.0023) for pioglitazone treatment. Metformin (low dose) and pioglitazone in combination resulted in 5.26 +/- 0.78 (P&amp;lt;0.0001) adenomas per animal. At the late stage intervention the average number of adenomas was 10.89 +/- 1.161 (P = 0.0007) for the low dose metformin, and 14.42 +/-1.24 (P = 0.1126, not significant) for pioglitazone treatment. Metformin (low dose) and pioglitazone in combination resulted in 9.77 +/- 0.85 (P&amp;lt;0.0001) adenomas per animal. The agents were well tolerated for the duration of the experiment from all physical appearance and other standard toxicities. However, animals treated with metformin had a 15% weight loss at the beginning of the experiment and completed the experiment with body weights 15% lower compared to non-metformin treated animals. Conclusions: We conclude metformin and pioglitazone are promising agents for lung adenoma prevention in A/J mice. We also conclude dose adjustments of these drugs may require further optimization. Drugs of the thiazolidinedione class and sulfonylureas are powerful controllers of glucose metabolism. Although we did not have observable toxicity in the animals, it is likely glucose metabolism was altered and this contributed to the 15% differences in weight between the animal groups. Therefore, well designed metabolomic studies may be helpful in the future. Citation Format: Donna Seabloom, Art Galbraith, Beverly Wuertz, Anna Haynes, Mark S. Miller, Vernon Steele, Lee Wattenberg, Frank G. Ondrey. Effects of dietary metformin/pioglitazone on lung adenoma formation in A/J mice. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-264. doi:10.1158/1538-7445.AM2015-LB-264

Abstract A56: A dual PI3K-mTOR inhibitor induced cardiac hypertrophy in mice: Role of the insulin signaling

Abstract Studies from us and others showed that mice with cardiomyocyte-specific overexpression of a dominant negative PI3Kp110α had smaller hearts but maintained normal cardiac function. Yet, these mice developed systolic heart failure in the presence of cardiac stress, such as chemotherapy drug doxorubicin and aortic stenosis. Currently, drugs targeting the PI3K pathway are being tested in clinical trials for cancer therapy. Therefore, it is important to assess the cardiac effects of pharmacological inhibition of this pathway. Here, we report that a dual PI3K-mTOR inhibitor, BEZ235 (BEZ), induced cardiac hypertrophy and subsequent heart failure in mice when it was used alone or in combination with doxorubicin. This effect of BEZ was associated with increased hepatic gluconeogenesis, hyperglycemia, hyperinsulinemia and increased activation of the IGFR/insulin receptor (IR) in the heart. In isolated cardiomyocyte culture, BEZ induced feedback activation of IGFR/IR, but this effect was negligible compared to the IGFR/IR activation in the presence of insulin. Injections of insulin in mice lowered blood glucose, improved glucose and pyruvate tolerance but further increased the activation of IGFR/IR in the heart and aggravated BEZ-induced cardiac dysfunction; whereas OSI-906, an IGFR/IR inhibitor, alleviated this cardiac dysfunction. In addition, low dose Metformin significantly prolonged survival and improved cardiac function in BEZ-treated mice. Taken together, these results identified hyperinsulinemia, a systematic effect of the drug, as one of the mechanisms of BEZ-induced cardiac hypertrophy, arguing animal studies are indispensable for evaluating drug toxicity. They also suggest that Metformin but not insulin should be considered for controlling hyperglycemia and preventing the cardiac side effects that may be caused by PI3K pathway inhibitors in clinic. Citation Format: Jillian Onufrak, Yongayo Yang, Juyong Lee, John Fuseler, Maoyun Sun, Sharath Sasi, J. Tyson McDonald, Lynn Hlatky, Robert L. Price, Joseph Carrozza, David Goukassian, Thomas K. Borg, James P. Morgan, Xinhua Yan. A dual PI3K-mTOR inhibitor induced cardiac hypertrophy in mice: Role of the insulin signaling. [abstract]. In: Proceedings of the AACR Special Conference: Targeting the PI3K-mTOR Network in Cancer; Sep 14-17, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(7 Suppl):Abstract nr A56.

Metformin reduces the endotoxin-induced down-regulation of apolipoprotein E gene expression in macrophages

The atheroprotective role of macrophage-derived apolipoprotein E (apoE) is well known. Our previous reports demonstrated that inflammatory stress down-regulates apoE expression in macrophages, aggravating atherogenesis. Metformin, extensively used as an anti-diabetic drug, has also anti-inflammatory properties, and thus confers vascular protection. In this study, we questioned whether metformin could have an effect on apoE expression in macrophages in normal conditions or under lipopolysaccharide (LPS)-induced stress. The results showed that metformin slightly increases the apoE expression only at high doses (5–10 mM). Low doses of metformin (1–3 mM) significantly reduce the LPS down-regulatory effect on apoE expression in macrophages. Our experiments demonstrated that LPS-induced NF-κB binds to the macrophage-specific distal regulatory element of apoE gene, namely to the multienhancer 2 (ME.2) and its 5′-deletion fragments. The NF-κB binding on ME.2 and apoE promoter has a down-regulatory effect. In addition, data revealed that metformin impairs NF-κB nuclear translocation, and thus, improves the apoE levels in macrophages under inflammatory stress. The positive effect of metformin in the inflammatory states, its clinical safety and low cost, make this drug a potential adjuvant in the therapeutic strategies for atherosclerosis.

Anti-diabetic therapies and the risk of acute pancreatitis: a nationwide retrospective cohort study from Taiwan.

To examine the relationship between different anti-diabetic therapies (dipeptidyl peptidase-4 (DPP-4), metformin and sulfonylureas) and risk of acute pancreatitis among type 2 diabetic patients in Taiwan, and explore each drug's dose-response relationship. We derived a nationwide retrospective cohort of patients with type 2 diabetes in Taiwan. The inclusion criteria are adult diabetic patients with continuous baseline enrollment, new users of the studied drugs, and without missing demographics. There were 4113/101 498/44 772 DPP-4/Metformin/Sulfonylurea users. Adjusted hazards ratios for pancreatitis associated with DPP-4, derived from Cox proportional hazard models with propensity score weighting, were estimated; dose-response analyses were also conducted. Dipeptidyl peptidase-4 was statistically significantly associated with a decreased risk of acute pancreatitis compared with sulfonylureas (adjusted HR: 0.36, 95%CI [0.17, 0.75]) but not metformin (adjusted HR: 0.67, 95%CI [0.32, 1.41]); metformin was statistically significantly associated with a lower risk of pancreatitis than sulfonylurea (adjusted HR: 0. 53; 95%CI [0.37, 0.76]). In addition, low-dose metformin was statistically significantly associated with a lower risk of pancreatitis compared with high-dose metformin (HR: 0.65; 95%CI [0.44, 0.97]). Our findings suggest that sulfonylureas may potentially be associated with an increased risk of pancreatitis compared with DPP-4 or metformin. Studies with longer follow up, larger sample sizes, and more precise capture of confounders may be needed to determine the risk of pancreatitis associated with incretin based therapies.

Efficacy and safety of linagliptin co-administered with low-dose metformin once daily versus high-dose metformin twice daily in treatment-naïve patients with type 2 diabetes: a double-blind randomized trial.

IntroductionThe aim of this study was to investigate the efficacy and safety of linagliptin + low-dose (LD) metformin once daily versus high-dose (HD) metformin twice daily in treatment-naïve patients with type 2 diabetes.MethodsPatients (n = 689) were randomized (1:1) to double-blind treatment with linagliptin 5 mg + LD metformin (1000 mg) or HD metformin (2000 mg) for 14 weeks. Metformin was initiated at 500 mg/day and up-titrated within 2 weeks; the dose then remained unchanged. The primary endpoint was change in glycated hemoglobin (HbA1c) from baseline to Week 14 in patients who tolerated a daily metformin dose of ≥1000 mg after 2 weeks.ResultsAt Week 14, HbA1c changed from a mean baseline of 8.0% (64 mmol/mol) by −0.99% (−11 mmol/mol) for linagliptin + LD metformin, and −0.98% (−11 mmol/mol) for HD metformin [treatment difference −0.01% (95% confidence interval −0.13, 0.12) (0 mmol/mol), P = 0.8924]. The proportion of patients who achieved HbA1c <7.0% (53 mmol/mol) without occurrence of moderate or severe gastrointestinal (GI) events (including abdominal pain, nausea, vomiting, diarrhea, and decreased appetite) was the same in both groups (51.3% for both). Although the occurrence of moderate or severe GI events was similar, the linagliptin + LD metformin group had fewer mild GI events (18.5% versus 24.3%). The incidence of hypoglycemia was low in both groups.ConclusionLinagliptin + LD metformin combination showed similar efficacy and safety to HD metformin. This combination may be an alternative treatment option in patients who may have difficulty tolerating metformin doses >1000 mg/day.FundingBoehringer Ingelheim.Electronic supplementary materialThe online version of this article (doi:10.1007/s12325-015-0195-3) contains supplementary material, which is available to authorized users.

Effects of different doses of metformin treatment for 6 months on aberrant crypt foci in Chinese patients with impaired glucose tolerance.

This research was carried out to evaluate the chemopreventive effects of different doses of metformin treatment for 6 months on rectal aberrant crypt foci (ACF) in patients with impaired glucose tolerance (IGT). A total of 120 Chinese patients with IGT were enrolled and assigned randomly to a low-dose metformin group (n=30, metformin at 250 mg/day), a middle-dose metformin group (n=30, metformin at 500 mg/day), a high-dose metformin group (n=30, metformin at 1500 mg/day), and a control (untreated with metformin) group (n=30). Each participant was followed for 6 months by protocol, and the number of ACF per patient in the above four groups was examined by magnifying colonoscopy before, and after 3 and 6 months of, treatment. The mean ACF numbers in both the middle-dose and the high-dose metformin groups were significantly decreased at 3 as well as 6 months of treatment, whereas they did not change in the low-dose metformin and the untreated groups. In the high-dose metformin group, BMI, waist circumference, fasting plasma glucose, homeostatic model assessment of insulin resistance index, and 2-h plasma glucose were significantly decreased. However, no such change was observed in the middle-dose metformin group. Changes in the ACF number correlated positively with changes in the homeostatic model assessment of insulin resistance (r=0.273, P=0.013), BMI (r=0.241, P=0.042), and 2-h plasma glucose (r=0.252, P=0.037), respectively, in the high-dose metformin group, but no such correlation was observed in the middle-dose metformin group. Metformin suppressed ACF formation in IGT patients in a dose-dependent manner, possibly through direct and indirect (attenuating insulin resistance) mechanisms.

Starting with low dose sulfonylurea and metformin in early stage type 2 diabetes mellitus.

Starting with low dose sulfonylurea and metformin in early stage type 2 diabetes mellitus.

Inhibition of Polo-like Kinase 1 (Plk1) Enhances the Antineoplastic Activity of Metformin in Prostate Cancer

The widely used anti-diabetic drug metformin has been shown to exert strong antineoplastic actions in numerous tumor types, including prostate cancer (PCa). In this study, we show that BI2536, a specific Plk1 inhibitor, acted synergistically with metformin in inhibiting PCa cell proliferation. Furthermore, we also provide evidence that Plk1 inhibition makes PCa cells carrying WT p53 much more sensitive to low-dose metformin treatment. Mechanistically, we found that co-treatment with BI2536 and metformin induced p53-dependent apoptosis and further activated the p53/Redd-1 pathway. Moreover, we also show that BI2536 treatment inhibited metformin-induced glycolysis and glutamine anaplerosis, both of which are survival responses of cells against mitochondrial poisons. Finally, we confirmed the cell-based observations using both cultured cell-derived and patient-derived xenograft studies. Collectively, our findings support another promising therapeutic strategy by combining two well tolerated drugs against PCa proliferation and the progression of androgen-dependent PCa to the castration-resistant stage.

Efficacy and safety of dapagliflozin monotherapy in people with Type 2 diabetes: a randomized double-blind placebo-controlled 102-week trial.

To assess initial pharmacotherapy of Type 2 diabetes with the sodium-glucose cotransporter-2 inhibitor dapagliflozin. This double-blind, placebo-controlled trial, randomly allocated people with Type 2 diabetes aged 18-77 years and inadequate glycaemic control on diet and exercise [HbA1c 53-86 mmol/mol (7.0-10.0%)] to receive placebo (n = 75) or dapagliflozin monotherapy 2.5 mg (n = 65), 5 mg (n = 64) or 10 mg (n = 70) once daily in the morning. After 24 weeks, low-dose double-blind metformin 500 mg/day was added to the placebo group regimen (placebo+low-dose metformin group). Changes in HbA1c level, fasting plasma glucose and body weight, as well as adverse events, were assessed over 102 weeks. Of the 274 participants randomized, 167 completed the study (60.9%). At 102 weeks, significant differences vs placebo+low-dose metformin with dapagliflozin 5 and 10 mg were observed for HbA1c (-5.8 mmol/mol [-0.53%], P = 0.018; and -4.8 mmol/mol [-0.44%], P = 0.048), respectively); and for FPG (-0.69 mmol/L, P = 0.044; and -1.12 mmol/l, P = 0.001, respectively). For body weight, the difference between the dapagliflozin 10-mg group and the placebo+low-dose metformin group was significant (-2.60 kg; P = 0.016). Hypoglycaemic events were uncommon, with rates of 5.3% for placebo+low-dose metformin group and 0-4.6% for the dapagliflozin groups. Genital infections and urinary tract infections were more common in the dapagliflozin groups than in the placebo+low-dose metformin group. Dapagliflozin as monotherapy in treatment-naïve people with early Type 2 diabetes improved glycaemic control and reduced weight without increasing hypoglycaemia over 102 weeks. Dapagliflozin may provide an alternative initial pharmacotherapy in such people.

Abstract 780: Metformin induces apoptotic cell death and inhibits CD133+ cancer stem cells in 5-Fu-resistant colorectal cancer cells

Abstract Colorectal cancer (CRC) is the third most common cancer and estimated cancer related death is high in worldwide. 5-Fluorouracil (5-Fu) is common used chemotherapeutic agent for colorectal cancer. Nevertheless the use frequency, the resistance to 5-Fu is still a critical problem. To improvement of therapeutic effects of 5-Fu, there are the new chemotherapeutic strategies like FOLFOX and FORFIRI, combination treatment 5-Fu with oxaliplatin or irinotecan. However, it is arguable that the side effects and efficiency of these strategies. Metformin is widely used therapeutic agent for type II diabetics, obesity, and polycystic ovarian syndrome with limited side effects. Recently, there are some evidence that metformin has anticancer effects for some types of cancers e.g. breast, pancreases, prostate, and colon. Recently, correlation of metformin and cancer stem cell population was proved. Here, we examined that metformin effects on parental colorectal cancer cells and their 5-Fu-resistant colorectal cancer cells. Metformin has the anticancer effects in parental cells and their 5-Fu-resistant cells in both cell lines. As treated with metformin, wound healing ability is decreased in both cell lines. Cell proliferation was 41.7% decreased in parental cells and 30.6% in 5-Fu-resistant cells. Also, expression of PARP and caspase-3 were induced by metformin dose dependent manner in both cell lines. It is suggested that metformin induces inhibition of cell proliferation and increased apoptosis. In addition, metformin treatment affects cell cycle; subG1 stage was increased to 1.7 fold and G2/M stage was increased to 1.6 fold in both cell lines. It means that metformin induces cell death and leads cell cycle arrest. However, there are no significant synergistic effect in cell proliferation, apoptosis, and cell cycle change with combination treatment of 5-Fu and metformin. CD133+ cancer stem cell population was decreased in 20 to 40 % as treated with 5-Fu and low dose of metformin to parental cells. On the other hand, CD133+ population in 5-Fu-resistant cells was affected in only low dose of metformin not 5-Fu. In sum, metformin has anticancer effects via inhibition of cell proliferation, cell cycle changes and metformin decreases CD133+ cancer stem cell population. Further studies will be necessary to verify the mechanisms that metformin decreases CD133+ cancer stem cell population in colorectal cancer cell lines. Citation Format: Sunghee Kim, Ja-Lok Ku. Metformin induces apoptotic cell death and inhibits CD133+ cancer stem cells in 5-Fu-resistant colorectal cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 780. doi:10.1158/1538-7445.AM2014-780

Abstract 1011: Metformin inhibits angiogenesis, local and metastatic growth of triple-negative breast cancer by targeting two classes of adipose tissue progenitors

Abstract We have recently reported that human white adipose tissue (WAT) contains two classes of CD45-CD34+ progenitors with cooperative roles in triple negative breast cancer progression. In orthotopic murine models we found that 1) purified human WAT CD34+CD13+ mesenchymal adipose stromal cell progenitors (ASCs) were not able to migrate but promoted local tumor growth in the mammary fat pad and 2) purified human WAT CD34+CD31+ endothelial progenitors (EPCs) were able to migrate towards lymph nodes and blood and promoted breast cancer cell EMT, migration, invasion and metastatic growth (Orecchioni et al, 2013). Here we report that in several in vitro and in vivo models the biguanide Metformin, a drug commonly used in type 2 diabetes management, is able to inhibit angiogenesis, local and metastatic growth of triple negative breast cancer by targeting WAT progenitors. First, we and others (Dallaglio et al, in press) have found in collaborative studies that Metformin inhibits the formation of capillary-like networks by HUVEC cells. This effect was partially AMPK-dependent. Metformin inhibited VEGF-dependent activation of ERK1/2, angiogenesis in matrigel pellets in vivo, and decreased microvessel density in tumor-free mice. The effect of Metformin on WAT progenitors was then studied in vivo in several immune-competent and immune-deficient murine strains with and without triple negative breast cancer. In immune-competent mice, low-dose Metformin (2mg/mL drinking water) induced apoptosis and increased hypoxia of CD34+CD31+ WAT EPCs. As a result of low-dose Metformin administration, WAT and cancer vessels were quantitatively reduced, had a significant impairment of the pericyte/endothelial cell ratio and displayed a branching and dysplastic phenotype. This effect was also observed in immune-competent mice on high fat diet receiving Metformin. WAT CD34+ ASC were targeted by higher doses of Metformin, which were associated with a reduced pericyte coverage of new blood vessels. As Metformin is frequently administered along with aspirin and beta-blockers in diabetic and obese patients, we studied in vivo the association of these three drugs in murine models of triple negative breast cancer. In several immune-deficient murine models, the beta-blocker Atenolol significantly synergized with Metformin in inhibiting both local and metastatic breast cancer growth. In immune-competent murine strains, the anti-metastatic effect of Metformin and Atenolol was further enhanced by the addition of aspirin. These effects were observed in several murine models generated by both p53 mutated or p53 wild type triple negative breast cancer cells. We are currently investigating the molecular mechanisms used by Metformin to inhibit WAT progenitors and the most efficient schedules of administration of Metformin, Atenolol and Aspirin to target local and metastatic breast cancer growth. Citation Format: Stefania Orecchioni, Giuliana Gregato, Francesca Reggiani, Patrizia Mancuso, Angelica Calleri, Giovanna Talarico, Valentina Labanca, Francesco Bertolini. Metformin inhibits angiogenesis, local and metastatic growth of triple-negative breast cancer by targeting two classes of adipose tissue progenitors. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1011. doi:10.1158/1538-7445.AM2014-1011

Optimizing clinical outcomes resulting from glucose‐lowering therapies in type 2 diabetes: increased confidence about the DPP‐4 inhibitors and continued concerns regarding sulphonylureas and exogenous insulin

Optimizing clinical outcomes resulting from glucose‐lowering therapies in type 2 diabetes: increased confidence about the <scp>DPP</scp>‐4 inhibitors and continued concerns regarding sulphonylureas and exogenous insulin

Multifactorial effects of vildagliptin added to ongoing metformin therapy in patients with type 2 diabetes mellitus

BackgroundTo assess the efficacy of a vildagliptin and metformin combination therapy to a metformin monotherapy in type 2 diabetes mellitus patients. MethodsSixty-one patients with diabetes inadequately controlled by a metformin monotherapy were randomized to treatment with a combination therapy of vildagliptin 100mg and a metformin versus metformin monotherapy. This was a 12-week randomized parallel group study. During the study we assessed parameters of glycemic and lipid metabolism as well as the treatment effects on the release of proinflammatory and antiinflammatory cytokines. ResultsCompared with baseline values we observed a significant improvement of glycaemic parameters such as HbA1c, FPG, PPG, FPI, HOMA-IR and HOMA-β index as well as decrease of TCh, TG and LDL and an increase of HDL with the greatest extent of vildagliptin plus a low-dose metformin therapy group. A metformin combination therapy significantly decreased such inflamation parameters as hs-CRP, ox-LDL, TNF-α and IL-1β levels relative to monotherapies. All treatments were well tolerated and there was no incidence of hypoglycaemia. ConclusionsVildagliptin added to an ongoing metformin therapy allows to achieve better metabolic control parameters in comparison with a metformin monotherapy and the combination treatment is well tolerated and has a low risk of serious adverse effects.

Reprogramming ovarian and breast cancer cells into non-cancerous cells by low-dose metformin or SN-38 through FOXO3 activation.

Cancer is a leading cause of death worldwide. Because the cytotoxic effects of conventional chemotherapies often harm normal tissue cells along with cancer cells, conventional chemotherapies cause many unwanted or intolerable side effects. Thus, there is an unmet medical need to establish a paradigm of chemotherapy-induced differentiation of cancer cells with tolerable side effects. Here we show that low-dose metformin or SN-38 inhibits cell growth or survival in ovarian and breast cancer cells and suppresses their tumor growth in vivo. Low-dose metformin or SN-38 increases FOXO3 nuclear localization as well as the amount of DNA damage markers and downregulates the expression of a cancer-stemness marker CD44 and other stemness markers, including Nanog, Oct-4, and c-Myc, in these cancer cells. This treatment also inhibits spheroid body-formation in 3-dimensional culture. In contrast, silencing FOXO3 diminishes all these cellular events when ovarian/breast cancer cells are treated with the mentioned drugs. These results suggest that low-dose metformin or SN-38 may reprogram these cancer cells into non-cancerous cells in a FOXO3-dependent manner, and may allow patients to overcome these cancers with minimal side effects.

Metformin improves skin flap survival through nitric oxide system

BackgroundMetformin has shown cardioprotective effects in experimental models of ischemia reperfusion, which is partially mediated through nitric oxide (NO) synthesis. We investigated the effects of metformin pretreatment in a rat model of random-pattern skin flap, and the probable role of NO system. Materials and methodsIn the first experiment, the rats received increasing doses of metformin (150, 200, and 300 mg/kg), 4 h before the procedure. Dorsal skin flaps with caudal pedicles were elevated at the midline and flap survival was measured 7 d after surgery. Pathologic review of the skin flap specimen was performed in a subset of animals. In the second experiment, for evaluation of the role of NO, an NO synthase inhibitor N-nitro-L-arginine methyl ester hydrochloride (L-NAME) was administered with and without the effective dose of metformin. In the next experiment, subtherapeutic dose of NO precursor, L-Arginine, was administered with and without subeffective dose of metformin. ResultsMetformin pretreatment at doses of 200 and 300 mg/kg significantly increased skin flap survival rate. However, administration of L-NAME abolished the protective effects of metformin. On the other hand, subtherapeutic dose of L-arginine augmented the effects of low-dose metformin and significantly increased skin flap survival. Skin flaps from those rats that received 300 mg/kg metformin pretreatment and those treated with subtherapeutic doses of L-arginine and metformin showed increased vasodilation compared with control group. ConclusionsMetformin pretreatment can improve skin flap survival through an NO dependent pathway.

Metformin suppresses gluconeogenesis by inhibiting mitochondrial glycerophosphate dehydrogenase.

Metformin is considered to be one of the most effective therapeutics for the treatment of type 2 diabetes (T2D) since it specifically reduces hepatic gluconeogenesis without increasing insulin secretion, inducing weight gain, or posing a risk of hypoglycemia1,2. For over half a century, this agent has been prescribed to T2D patients worldwide, yet the underlying mechanism by which metformin inhibits hepatic gluconeogenesis remains unknown. Here we show that metformin non-competitively inhibits the redox shuttle enzyme mitochondrial glycerophosphate dehydrogenase (mGPD), resulting in an altered hepatocellular redox state, reduced conversion of lactate and glycerol to glucose, and decreased hepatic gluconeogenesis. Acute and chronic low-dose metformin treatment effectively reduced endogenous glucose production (EGP), while increasing cytosolic redox and decreasing mitochondrial redox states. Antisense oligonucleotide (ASO) knockdown of hepatic mGPD in rats resulted in a phenotype akin to chronic metformin treatment, and abrogated metformin-mediated increases in cytosolic redox state, decrease in plasma glucose concentrations and inhibition of EGP. These findings were replicated in whole-body mGPD knockout mice. These results have significant implications for understanding the mechanism of metformin’s blood glucose lowering effects and provide a novel therapeutic target for T2D.

Effects of low dose metformin in adolescents with type I diabetes mellitus: a randomized, double-blinded placebo-controlled study

Insulin resistance increases during adolescence in those with type 1 diabetes mellitus (T1DM), complicating glycemic control and potentially increasing cardiovascular disease (CVD) risk. Metformin, typically used in type 2 diabetes mellitus (T2DM), is a possible adjunct therapy in T1DM to help improve glycemic control and insulin sensitivity. We hypothesized that metformin would improve metabolic parameters in adolescents with T1DM. This randomized, double-blinded, placebo-controlled trial included 74 pubertal adolescents (ages: 13-20 yr) with T1DM. Participants were randomized to receive either metformin or placebo for 6 months. Glycated hemoglobin (HbA1c), insulin dose, waist circumference, body mass index (BMI), and blood pressure were measured at baseline, 3 and 6 months, with fasting lipids measured at baseline and 6 months. Total daily insulin dose, BMI z-score and waist circumference significantly decreased at 3 and 6 months compared to baseline within the metformin group, even among normal-weight participants. In the placebo group, total insulin dose and systolic blood pressure increased significantly at 3 months and total insulin dose increased significantly at 6 months. No significant change was observed in HbA1c at any time point between metformin and placebo groups or within either group. Low-dose metformin likely improves BMI as well as insulin sensitivity in T1DM adolescents, as indicated by a decrease in total daily insulin dose. The decrease in waist circumference indicates that fat distribution is also likely impacted by metformin in T1DM. Further studies with higher metformin doses and more detailed measurements are needed to confirm these results, their underlying mechanisms, and potential impact on CVD in T1DM youth.