Serum ischaemic-modified albumin levels might not be a marker of oxidative stress in patients with hypothyroidism

A meta-analysis of the association of serum ischaemia-modified albumin levels with human hypothyroidism and hyperthyroidism

Serum levels of ischaemia-modified albumin (IMA) have been studied as a novel and simple measure of oxidative stress (OXS) in different thyroid pathologies. However, results of available studies in the literature were not consistent. This meta-analysis was attempted to quantify the overall effect size for serum IMA levels in human hypothyroidism (HT) and hyperthyroidism (HYT) and to study its associations with the thyroid profile. Databases of PubMed/Medline, EMBASE, Google Scholar, Web of Science and Science Direct were searched for articles. Data on serum IMA levels in HT, HYT patients and euthyroid controls were extracted to compute standardized mean differences (SMD) by the random-effects model. The associations between IMA and thyroid profile were computed by the meta-analysis of correlation coefficients. IMA levels in HT patients (SMD=1.12; Z=2.76; P=0.006) and HYT patients (SMD=1.64; Z=2.57; P=0.01) were significantly higher than in euthyroid controls and the thyroid treatment showed a favourble effect on serum IMA levels. There were strong and significant correlations between IMA and hormonal status in HT and HYT groups. This meta-analysis showing increased IMA level in both HT and HYT patients and its association with thyroid profile suggests that serum IMA could be used as a simple measure of increased OXS in thyroid dysfunction.

Associations of FPG, A1C and disease duration with protein markers of oxidative damage and antioxidative defense in type 2 diabetes and diabetic retinopathy

PURPOSE

To investigate the role of protein oxidative damage and antioxidant defense in relationship to hyperglycemia measured as fasting plasma glucose (FPG), glycated hemoglobin (A1C), and duration of disease in type 2 diabetes mellitus (DM) and diabetic retinopathy (DR).

METHODS

This study recruited 23 non-diabetic subjects, 16 DM patients without any complications and 18 DR patients. The serum ischemia modified albumin (IMA) and glutathione (GSH) levels were measured. The IMA results were corrected for serum albumin. Between-group differences were studied by analysis of variance and between-variable associations were studied by Spearman's and partial correlations.

RESULTS

IMA and cIMA values were elevated, whereas GSH was decreased in both patient groups vs controls (P<0.05), and the increase in IMA formation is not related to serum albumin changes. DR patients have much severe oxidative stress (OS) status with high IMA and cIMA, and low GSH than in the DM group (P<0.05). Both FPG and A1C levels were positively associated with IMA in DM group, while in the DR group, duration of disease too had a positive association with IMA. The antioxidant GSH had negative correlations with FPG (r=-0.52, P=0.02) and IMA (r=-0.49, P=0.03) in the DR group. Partial correlation analyses predicted mutual or independent associations among parameters.

CONCLUSIONS

Severe OS in DR has been associated with increased FPG, A1C, and disease duration. Both hyperglycemia and elevated oxidative damage detected as IMA are collectively associated with depleted GSH status. Our study unravels the need for monitoring of OS in addition to standard glycemic management in DR.