Oxidant and antioxidant parameters in prediabetes and diabetes

A systematic review and meta-analysis of ischemia-modified albumin in diabetes mellitus

Aim

There is an ongoing search for novel biomarkers of diabetes. We conducted a systematic review and meta-analysis of the serum concentrations of ischemia-modified albumin (IMA), a candidate biomarker of oxidative stress, acidosis, and ischemia, in patients with pre-diabetes, different types of diabetes mellitus (type 1, T1DM, type 2, T2DM, and gestational, GDM), and healthy controls.

Methods

We searched for case-control studies published in PubMed, Web of Science, and Scopus from inception to December 31, 2023. The risk of bias and the certainty of evidence were assessed using the Joanna Briggs Institute Critical Appraisal Checklist and GRADE, respectively.

Results

In 29 studies, T2DM patients had significantly higher IMA concentrations when compared to controls (standard mean difference, SMD = 1.83, 95 % CI 1.46 to 2.21, p˂0.001; I2 = 95.7 %, p < 0.001; low certainty of evidence). Significant associations were observed between the SMD and glycated hemoglobin (p = 0.007), creatinine (p = 0.003), triglycerides (p = 0.029), and the presence of diabetes complications (p = 0.003). Similar trends, albeit in a smaller number of studies, were observed in T1DM (two studies; SMD = 1.59, 95 % CI -0.09 to 3.26, p˂0.063; I2 = 95.8 %, p < 0.001), GDM (three studies; SMD = 3.41, 95 % CI 1.14 to 5.67, p = 0.003; I2 = 97.0 %, p < 0.001) and pre-diabetes (three studies; SMD = 15.25, 95 % CI 9.86 to 20.65, p˂0.001; I2 = 99.3 %, p < 0.001).

Conclusion

Our study suggests that IMA is a promising biomarker for determining the presence of oxidative stress, acidosis, and ischemia in pre-diabetes and T1DM, T2DM, and GDM. However, the utility of measuring circulating IMA warrants confirmation in prospective studies investigating clinical endpoints in pre-diabetes and in different types of diabetes (PROSPERO registration number: CRD42024504690).

Oxidative Status and Thiol/Disulfide Homeostasis Are Changed During 75 g Oral Glucose Tolerance Test over a Five-Hour Period

BACKGROUND

Oral glucose loading may affect oxidative status during oral glucose tolerance test (OGTT). We aimed to investigate how oxidant and antioxidant markers and thiol/disulfide parameters change during OGTT.

METHODS

OGTT was performed to 42 volunteers who were considered risk of type 2 diabetes and were divided into three groups (normoglycemic, prediabetes, diabetes) according glucose levels during OGTT. Glucose, insulin, c-peptide, total antioxidant status (TAS), total oxidant status (TOS), total thiol and native thiol were investigated with auto-anaylzer for five-hours period.

RESULTS

Decrease of TAS and increase of TOS levels began with the increase in glucose and insulin levels. The increase of TAS started at third hour and reached the highest levels at fifth hour. OSI levels were higher at fourth hour than fasting and first hours in normoglycemic and diabetes groups. In the prediabetic group, TAS were higher than the other groups, TOS peak was at the second hour (p < 0.05). Native thiol and total thiol levels showed variable course during OGTT, both parameters increased at the end of the process (p < 0.05). Disulfide levels showed an increase trend but it was not statistically different in normoglycemic and diabetes groups. In prediabetes group, second hour disulfide level was lower than fasting state and disulfide was significantly increased at third, fourth and fifth hours and fifth hour disulfide level was also higher than fasting.

CONCLUSION

Oxidative stress parameters and thiol/disulfide balance were found to deteriorate within five-hours after glucose loading in all groups. These results indicates that oxidative stress occurs during OGTT.