Effect of metformin combined with lifestyle modification versus lifestyle modification alone on proinflammatory-oxidative status in drug-naïve pre-diabetic and diabetic patients: A randomized controlled study

BACKGROUND

Targeting biomarkers of oxidative-proinflammatory stress may result in improvement of modifiable metabolic syndrome, pre-diabetes and diabetes risk factors and subsequent risk reduction.

METHODS

64 newly diagnosed antihyperglycemic treatment-naïve prediabetic and type 2 diabetes mellitus (T2DM) patients were randomly assigned using block design to either metformin combined with therapeutic lifestyle changes (TLC) or TLC alone. Body mass index (BMI), waist circumference, blood pressure, fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), fasting lipid profile, plasma oxidative status and tumor necrosis factor (TNF)-α were measured at baseline, after 3 months and after 6 months from baseline.

RESULTS

Except for HbA1c, baseline values did not differ significantly between the two groups. The post 3-months relative reductions in BMI (P=0.014) and HbA1c (P=0.037) in metformin combined with TLC intervention were significantly greater than those in TLC alone group. TNFα plasma levels were decreased significantly vs. baseline by metformin combined with TLC intervention (-22.90±46.76%, P=0.01). Conversely, TLC alone basically worsened proinflammatory status (42.40±40.82 %), P<0.001. Metformin with TLC treatment effected a therapeutic decrement of the oxidative stress (-15.44±35.32%, P=0.029 vs. baseline) unlike TLC alone (61.49±122.66%, P=0.01 vs. baseline). Both interventions' effects were sustained in the 6-month follow up periods.

CONCLUSION

In both intervention groups, the relative changes in plasma TNFα were significantly correlated (P<0.01) with systolic blood pressure and the relative changes in oxidative stress were markedly correlated (P<0.05) with total cholesterol.

Single nucleotide polymorphisms in the intergenic region between metformin transporter OCT2 and OCT3 coding genes are associated with short-term response to metformin monotherapy in type 2 diabetes mellitus patients

OBJECTIVES

High variability in clinical response to metformin is often observed in type 2 diabetes (T2D) patients, and it highlights the need for identification of genetic components affecting the efficiency of metformin therapy. Aim of this observational study is to evaluate the role of tagSNPs (tagging single nucleotide polymorphisms) from genomic regions coding for six metformin transporter genes with respect to the short-term efficiency.

DESIGN

102 tagSNPs in 6 genes coding for metformin transporters were genotyped in the group of 102 T2D patients treated with metformin for 3 months.

METHODS

Most significant hits were analyzed in the group of 131 T2D patients from Slovakia. Pharmacokinetic study in 25 healthy nondiabetic volunteers was conducted to investigate the effects of identified polymorphisms.

RESULTS

In the discovery group of 102 patients, minor alleles of rs3119309, rs7757336 and rs2481030 were significantly nominally associated with metformin inefficiency (P = 1.9 × 10^-6 to 8.1 × 10^-6). Effects of rs2481030 and rs7757336 did not replicate in the group of 131 T2DM patients from Slovakia alone, whereas rs7757336 was significantly associated with a reduced metformin response in combined group. In pharmacokinetic study, group of individuals harboring risk alleles of rs7757336 and rs2481030 displayed significantly reduced AUC_∞ of metformin in plasma.

CONCLUSIONS

For the first time, we have identified an association between the lack of metformin response and SNPs rs3119309 and rs7757336 located in the 5' flanking region of the genes coding for Organic cation transporter 2 and rs2481030 located in the 5' flanking region of Organic cation transporter 3 that was supported by the results of a pharmacokinetic study on 25 healthy volunteers.