The link between trace elements and metabolic syndrome/oxidative stress in essential hypertension with or without type 2 diabetes

The relationship between trace elements (TE) and essential hypertension (EH) is subtle and complex. This relationship is mediated by endothelial dysfunction, insulin resistance, oxidative stress (OS) and athero-inflammatory state. The aim of this study was to examine the TE impact; particularly selenium (Se), zinc (Zn), copper (Cu) and manganese (Mn) as predictive type 2 diabetes biomarkers in a hypertensive subject. The study was undertaken on 400 adult patients (40-60 years), who were divided in 4 groups: hypertensive (H), type 2 diabetes (T2D), hypertensive-diabetic (HD) and healthy group. Patients were phenotyped regarding their metabolic syndrome profile using the NCEP/ATPIII criteria. Hypertension was defined as systolic (SBP) and diastolic (DBP) blood pressure ≥140/90 mmHg, respectively. The SBP and DBP measurements by electronic blood pressure using Omron 705 CP® type. Insulin resistance was assessed by Homa-IR model. Metabolic and inflammatory parameters were determined by Cobas Integra®; the TE investigated by mass spectrometric atomic absorption; the OS markers evaluated by Randox kits. Serum Se concentrations are reduced in all groups, concomitantly with a marked depletion GPx activity in the HD group. However, Zn levels were decreased than in H and HD groups, but unchanged in T2D group. In contrast, Mn levels are increased in all groups; whereas the Cu levels increased only in H and HD groups, concomitantly with cytosolic SOD-Cu/Zn and mitochondrial SOD-Mn depletion. The Zn/Cu ratio decreases significantly in hypertensive group but not in diabetics groups. It appears that Zn/Cu ratio reflects the transition from hypertension phase to hypertension associated with T2D. Ultimately, TE plays an important role in the hypertension pathophysiology and can be considered as predictive T2D biomarkers in hypertensive patients.