[Advanced glycation and oxidation products in patients with atherosclerosis]

Oxidatively modified forms of albumin in patients with risk factors of metabolic syndrome

BACKGROUND

Metabolic syndrome (MetS) is a complex metabolic disease connected especially with lipid and carbohydrate disturbances. It is postulated that oxidative stress (OS) is linked to metabolic syndrome, constituting a novel component of its pathogenesis.

AIM

We aimed to examine the plasma level of oxidatively modified proteins--advanced oxidation protein products (AOPP) and ischemia modified albumin (IMA)--as well as thiol (SH) groups and evaluate their connection with metabolic agents in relation to MetS prevalence.

SUBJECTS AND METHODS

The levels of AOPP, IMA and SH groups were measured spectrophotometrically in 106 patients with MetS risk factors and in 32 control subjects.

RESULTS

The levels of examined parameters differed significantly between patients with MetS risk factors and the control group. AOPP significantly correlated with glucose (r = 0.30, p = 0.008), HDL-Ch (r = -0.34, p = 0.005), TG (r = 0.48, p < 0.001) and fibrinogen (r = 0.37, p < 0.001). The levels of AOPP and IMA increased progressively with the number of MetS risk factors, being the most significant for AOPP. The highest values of AOPP were associated with the presence of at least three risk factors. Only AOPP were an independent determinant for MetS occurrence in the studied population (OR = 2.72, p = 0.04). Mutual dependence between metabolic, oxidative stress and inflammatory parameters was revealed.

CONCLUSIONS

Oxidative modifications of proteins are increased in MetS and accumulation of MetS risk factors enhances manifestation of OS. AOPP is the most appropriate parameter for determination of OS, with potential diagnostic value in MetS patients.

A novel indicator of widespread endothelial damage and ischemia in diabetic patients: ischemia-modified albumin

Ischemia-modified albumin (IMA) is a novel marker of tissue ischemia. Nowadays, IMA is accepted as a marker of oxidative stress. In this study, we aimed at establishing an association between IMA and hyperglycemia, blood pressure, lipid parameters, microvascular complications, hsCRP, and microalbuminuria in type 2 diabetes patients without overt macrovascular disease and acute ischemia. Fifty type 2 diabetes mellitus patients without a history of macrovascular disease or end-stage renal disease were enrolled into the study. Age-matched 30 healthy individuals were also included in the study as a control group. Plasma IMA (0.329 ± 0.046 and 0.265 ± 0.045 AbsU; P < 0.0001) and hsCRP levels (0.51 ± 0.36 and 0.32 ± 0.17 mg/dl; P < 0.0001) were significantly higher in the diabetic group compared to healthy controls. IMA level was significantly correlated with hsCRP (r = 0.76; P < 0.0001), HbA1c (r = 0.72; P < 0.0001), microalbuminuria (r = 0.40; P = 0.004), systolic blood pressure (r = 0.28; P = 0.049), diastolic blood pressure (r = 0.44; P = 0.005), and HOMA-IR (r = 0.42; P = 0.005) levels in the entire diabetic subjects. In the diabetic patients group, presence of microalbuminuria was associated with a higher plasma IMA level (0.355 ± 0.035 and 0.265 ± 0.0045 AbsU; P < 0.0001, patients with microalbuminuria and control subjects, respectively). In the type 2 diabetes patients with nephropathy, IMA level (0.355 ± 0.035 and 0.311 ± 0.046 AbsU; P = 0.002) was determined higher compared to the diabetes patients without nephropathy. Diabetic patients without an overt cardiovascular disease still have a higher serum IMA level compared to healthy controls. The correlation of high plasma IMA levels with high hsCRP and microalbuminuria levels in diabetic subjects indicates the presence of a chronic ischemic process. Therefore, elevated IMA levels may indicate an underlying subclinical vascular disease in type 2 diabetes mellitus patients.