Circulating Oxidative Stress Biomarkers in Clinical Studies on Type 2 Diabetes and Its Complications

Table 1

Selected clinical retrospective studies on circulating oxidative stress markers in T2DM and prediabetes. All the studies included in this table were categorized under the class of evidence C, retrospective studies.

Disease and population	Sample	Markers	Observation	Information on medication or supplements	Reference
Prediabetics (); T2DM (); Controls ()	Urine	8-OHdG; 8-iso-PGF2α	↑ 8-iso-PGF2α and 8-OHdG in prediabetes compared to controls; ↑ 8-OHdG in T2DM patients compared to controls	No medication; No special diet; No supplements	[57]
Prediabetics (); Controls ()	Urine; Erythrocytes	8-iso-PGF2α; 8-OHdG; GSH/GSSG	No differences in 8-iso-PGF2α; ↑ 8-OHdG in prediabetes group compared to control; ↓ GSH/GSSG in prediabetes compared to control	Antihypertensive drugs: Prediabetes (35.8%); Controls (5.2%); Statins and anticoagulants: Controls (<4%); Prediabetes (<16%)	[59]
Prediabetics (); T2DM (); Controls ()	Plasma	8-iso-PGF2α; MDA; TAOC; SOD	↑ 8-iso-PGF2α and MDA in prediabetes and T2DM compared to controls; ↑ 8-iso-PGF2α in T2DM compared to prediabetes; ↓ TAOC in T2DM compared to controls and prediabetes; ↓ SOD in prediabetes compared to controls; No differences in TAOC between prediabetes and controls; ↓ SOD in T2DM compared to controls and prediabetes	No use of medication that affects glucose metabolism within 6 months	[58]
Prediabetics (); T2DM (); Controls ()	Plasma and erythrocyte	Nrf2; MDA; TAS; GPx; SOD; GSH	↓ TAS and GSH in controlled and uncontrolled T2DM compared to controls and prediabetes; ↓ Nrf2 in prediabetes and in uncontrolled T2DM compared to controls; ↑ MDA in uncontrolled T2DM compared to controls and prediabetes and in controlled T2DM compared to controls; ↑ GPx in uncontrolled T2DM compared to prediabetes; ↑ SOD in controlled and uncontrolled T2DM compared to prediabetes and controls	Not provided	[67]
Prediabetics (); T2DM (); Controls (); Ethnicity: whites, blacks, Brazilians	Plasma and erythrocyte	SOD; CAT; GPx; TBARS	No differences in TBARS, SOD, GPx, and CAT between prediabetes and controls; ↑ SOD and TBARS in T2DM compared to controls and prediabetes	Antihypertensive drugs: 76.4% of T2DM, 66.7% of the pre-DM, and 37.9% of the controls; Among T2DM: 92.7% sulphonylurea and/or biguanide	[60]
T2DM (); Controls ()	Serum	SOD; TBARS; GSH	↓ SOD and GSH in T2DM compared with controls; ↑ TBARS in T2DM compared with controls	Not provided	[61]
T2DM (); Controls ()	Plasma	FRAP	↓ FRAP lower in T2DM with poor glycaemic control than controls	T2DM treated with metformin and glibenclamide in combination with other	[99]
T2DM (); Controls ()	Plasma	Protein carbonyl; AOPP; Radical scavenging capacity of plasma	↑ protein carbonyl content and AOPPs in T2DM in comparison to healthy volunteers; ↓ Radical scavenging capacity of plasma in T2DM than controls	Not provided	[84]
T2DM (); Controls ()	Plasma	FRAP; GSH; GR; GPx	↑ FRAP and GR in T2DM compared to controls; ↓ GPx activity in T2DM compared to controls	Not provided	[98]
T2DM (); Controls ()	Plasma	GSH; GPx; TAS	↓ GSH, GPx in T2DM compared to controls; No differences in TAS	No use of vitamins, minerals, or other supplements	[100]
T2DM (); Controls ()	Plasma	HO1	↑ HO1 in T2DM compared to controls	Not provided	[110]
T2DM (); Controls (); Ethnicity: Indian	Serum	PON1	↑ PON1 in controls compared to T2DM	Not provided	[102]
T2DM (); Controls ()	Serum	PON1	↑ PON1 in controls compared to T2DM	Not provided	[103]
T2DM (); Controls ()	Serum	PON1	↑ PON1 in controls compared to T2DM	10 controls and 15% of T2DM were on active lipid-lowering treatment	[104]

8-iso-PGF2α: 8-iso- prostaglandin F2α ; 8-OHdG: 8-hydroxy-2-deoxyguanosine; AGEs: advanced glycation end products; AOPP: advanced oxidation protein products; CAT: catalase; FRAP: ferric reducing ability of plasma; GSH: reduced glutathione; GSSG: oxidized glutathione; GPx: glutathione peroxidase; GR: glutathione reductase; HNE: 4- hydroxy-2-nonenal; HO1: heme oxygenase; MDA: malondialdehyde; Nrf2: nuclear factor erythroid 2; PON1: paraoxonase 1; SOD: superoxide dismutase; TBARS: thiobarbituric acid reactive substances; TAS: total antioxidant status.