The Radioprotective Effect of Procaine and Procaine-Derived Product Gerovital H3 in Lymphocytes from Young and Aged Individuals.

Ionizing radiation induces genomic instability in living organisms, and several studies reported an ageing-dependent radiosensitivity. Chemical compounds, such as scavengers, radioprotectors, and modifiers, contribute to reducing the radiation-associated toxicity. These compounds are often antioxidants, and therefore, in order to be effective, they must be present before or during exposure to radiation. However, not all antioxidants provide radioprotection. In this study, we investigated the effects of procaine and of a procaine-based product Gerovital H3 (GH3) on the formation of endogenous and X-ray-induced DNA strand breaks in peripheral blood mononuclear cells (PBMCs) isolated from young and elderly individuals. Interestingly, GH3 showed the strongest radioprotective effects in PBMCs from young subjects, while procaine reduced the endogenous amount of DNA strand breaks more pronounced in aged individuals. Both procaine and GH3 inhibited lipid peroxidation, but procaine was more effective in inhibiting mitochondria free radicals' generation, while GH3 showed a higher antioxidant action on macrophage-induced low-density lipoprotein oxidation. Our findings provide new insights into the mechanisms underlying the distinct effects of procaine and GH3 on DNA damage.

Insulin-Leptin Axis, Cardiometabolic Risk and Oxidative Stress in Elderly with Metabolic Syndrome.

Insulin and leptin have an overlapping anorexigenic action as well as opposite effects on glucose and lipid metabolism. The study focuses on the biochemical and clinical relevance of new indices of insulin-leptin axis utilized in the study of the relationships between leptinemia, insulin sensitivity and oxidative stress, in elderly subjects with metabolic syndrome. We conducted clinical studies on elderly people with metabolic syndrome versus control subjects by creating new insulin-adipogenic indices, namely Insulin-to-Leptin Ratio (ILR) and Insulin-Adipogenic Resistance index (IAR-index). Inflammation and oxidative stress biomarkers evaluated were the high-sensitivity C-reactive protein (hsCRP), the advanced oxidation protein products (AOPP), and the serum antioxidant capacity measured as ferric reducing antioxidant potential (FRAP). The metabolic syndrome group showed significantly (p<0.01) lower levels of ILR and not significant (p=0.09) higher values of IAR-index, as compared to the control group. In metabolic syndrome subjects, the IAR-index was significantly positively correlated with uric acid (r=0.313, p<0.05), FRAP (r=0.347, p<0.05) and AOPP (r=0.677, p<0.01), and negatively correlated with HDL-cholesterol (r=- 0.340, p<0.05) as well as with the ratio FRAP/uric acid (r=- 0.315, p<0.05). ILR and IAR-index reflected the biological state of adipose and pancreatic ß-cells and seem to depict the adipo-insular axis status related to metabolic and oxidative stress better than individual markers. Therefore, ILR and IAR-index could represent integrated high-potential biomarkers for disease and patient stratification.

Adiponectin: possible link between metabolic stress and oxidative stress in the elderly.

OBJECTIVE: The aim of this study was to evaluate the relationships between the serum levels of adiponectin and systemic oxidative stress exerted on lipids, proteins, as well as endothelial function and cardiovascular diseases (CVD) risk markers, in elderly subjects with metabolic syndrome (MS). METHODS: The serum advanced glycation and oxidation protein products, low-density lipoprotein susceptibility to oxidation (oxLDL), nitric oxide metabolic pathway products (NOx), serum lipid peroxidation, as well as total antioxidant/oxidative capacity (TAC/TOC), were analyzed in elderly subjects with MS (n = 44), compared to aged-matched control (n = 39). RESULTS: We pointed out significantly lower levels of adiponectin in elderly MS subjects concomitantly with significantly higher levels of oxidative stress and CVD risk markers. Significant positive correlations were found between serum adiponectin levels and HDL-cholesterol (p < 0.05) and the total cholesterol/LDL-cholesterol ratio (p < 0.01). Additionally, adiponectin levels were significantly inversely associated with insulin resistance index (HOMA-IR, r = -0.348; p < 0.05) and serum lipid peroxidation (r = -0.337; p < 0.05), and significantly positively with the antioxidant capacity (TAC, r = 0.339; p < 0.05). Conversely, adiponectin levels were significantly negatively (r = -0.310; p < 0.05) associated with serum uric acid concentration. CONCLUSIONS: The major protective role of adiponectin versus stress related to an impaired glucose and lipid metabolism suggests that adiponectin plays a critical role in adiposity-related metabolic stress and redox homeostasis.

Oxidized LDL and NO synthesis--Biomarkers of endothelial dysfunction and ageing.

Oxidized LDL (oxLDL) and nitric oxide (NO) exert contradictory actions within the vascular endothelium microenvironment influencing key events in atherogenesis. OxLDL and NO are so far regarded as representative parameters of oxidative stress and endothelial dysfunction, new targets in prevention, diagnosis and therapy of cardiovascular diseases, and also as candidate biomarkers in evaluating the human biological age. The aim of this review is to explore recent literature on molecular mechanisms and pathophysiological relationships between LDL oxidation, NO synthesis and vascular endothelium function/dysfunction in ageing, focusing on the following aspects: (1) the impact of metabolic status on both LDL oxidation and NO synthesis in relation with oxidative stress, (2) the use of oxidized LDL and NO activity as biomarkers in human studies reporting on cardiovascular outcomes, and (3) evidences supporting the importance of oxidized LDL and NO activity as relevant biomarkers in vascular ageing and age-related diseases.

Validation of protein carbonyl measurement: a multi-centre study.

Protein carbonyls are widely analysed as a measure of protein oxidation. Several different methods exist for their determination. A previous study had described orders of magnitude variance that existed when protein carbonyls were analysed in a single laboratory by ELISA using different commercial kits. We have further explored the potential causes of variance in carbonyl analysis in a ring study. A soluble protein fraction was prepared from rat liver and exposed to 0, 5 and 15min of UV irradiation. Lyophilised preparations were distributed to six different laboratories that routinely undertook protein carbonyl analysis across Europe. ELISA and Western blotting techniques detected an increase in protein carbonyl formation between 0 and 5min of UV irradiation irrespective of method used. After irradiation for 15min, less oxidation was detected by half of the laboratories than after 5min irradiation. Three of the four ELISA carbonyl results fell within 95% confidence intervals. Likely errors in calculating absolute carbonyl values may be attributed to differences in standardisation. Out of up to 88 proteins identified as containing carbonyl groups after tryptic cleavage of irradiated and control liver proteins, only seven were common in all three liver preparations. Lysine and arginine residues modified by carbonyls are likely to be resistant to tryptic proteolysis. Use of a cocktail of proteases may increase the recovery of oxidised peptides. In conclusion, standardisation is critical for carbonyl analysis and heavily oxidised proteins may not be effectively analysed by any existing technique.

Advanced oxidative and glycoxidative protein damage markers in the elderly with type 2 diabetes.

We aimed to explore the association of advanced oxidation and advanced glycation of proteins, and their interrelations with endothelial nitric oxide synthesis, oxidative stress, metabolic profile as well as other atherosclerotic risk markers in prediabetic and diabetic elderly subjects. Advanced glycation end products (AGEs), advanced oxidation protein products (AOPPs), low-density lipoprotein susceptibility to oxidation (oxLDL) and nitric oxide metabolic pathway products (NOx) were assessed in subjects with impaired fasting glucose (prediabetes, IFG; n=90), and type 2 diabetes mellitus (T2DM, n=95) versus control subjects (n=88). Higher levels of AOPPs, AGEs, oxLDL, NOx, atherosclerosis risk markers, and insulin resistance were pointed out in IFG and T2DM groups compared with control. Strong positive associations (p<0.01) of AGEs with fasting glucose and HbA1c were found in both hyperglycemic groups, whereas AOPPs were significantly correlated (p<0.01) only in T2DM. In T2DM, AGEs and AOPPs significantly (p<0.01) correlated with insulin resistance index HOMA-IR, oxLDL and small LDL particle size (TG/HDL-C), and positively with NOx. Direct associations of AGEs and AOPPs with TC/HDL-C and oxLDL/HDL-C, and AGEs-AOPPs interrelations (p<0.01) were identified in IFG and T2DM groups. AGEs and AOPPs in combination with oxLDL and NOx could be important biomarkers for evaluating the association between diabetes and atherosclerotic disorders in aging diabetic patients. BIOLOGICAL SIGNIFICANCE: In the present study we have made an attempt to approach the biological and clinical significance of the oxidative and glycoxidative protein damage, in subjects with prediabetes and type-2 diabetes mellitus. AGEs and AOPPs in combination with oxLDL and NOx appear to be important biomarkers for evaluating the association between diabetes and atherosclerotic disorders in aging diabetic patients. More importantly, this cluster of biomarkers that links the short term, "real time" metabolic impairment parameters (NOx, serum glucose, HOMA-IR, serum lipid profile) and the "metabolic memory" markers resulting from the long-term hyperglycemia and hyperlipidemia-induced oxidative stress (HbA1c, AGEs, AOPPs and oxLDL), could be valuable in predicting not only vascular complications in T2DM, but also the onset of diabetes, hence enabling therapeutic interventions from the early stages of diabetes. This article is part of a Special Issue entitled: Posttranslational Protein modifications in biology and Medicine.

Vitamin D status and oxidative stress markers in the elderly with impaired fasting glucose and type 2 diabetes mellitus.

BACKGROUND AND AIMS: Vitamin D deficiency has been identified in the elderly as a potential risk factor for cardiovascular disease development, possibly through its association with other risk factors, such as type 2 diabetes mellitus (T2DM), hypercholesterolemia and hypertension. The aim of this cross-sectional study was to evaluate the vitamin D status in elderly subjects with impaired fasting glucose (IFG) or T2DM, and to examine its relationships to systemic oxidative stress and biochemical markers of endothelial dysfunction. METHODS: Serum 25-hydroxyvitamin D [25(OH)D], fasting glucose, insulin, lipid profile, advanced glycation end products (AGEs), advanced oxidation protein products (AOPPs), low-density lipoprotein susceptibility to oxidation (oxLDL) and nitric oxide metabolic pathway products (NOx) were analyzed in elderly subjects with IFG (n=30) and T2DM (n=35) compared with aged-matched controls (n=25). RESULTS: 25(OH)D levels in the IFG and T2DM groups were significantly lower than in controls (31.9±1.9 and 28.5±1.9 vs 39.4±2.4 ng/mL, p<0.001), and associated with significantly (p<0.001) higher levels of the oxidative stress parameters AGEs, AOPPs, oxLDL and NOx. Hypovitaminosis D [25(OH)D)<30 ng/ml] markedly enhanced the oxidative stress and cardiovascular risk in hyperglycemic subjects compared with sufficient vitamin D [25(OH)D)≥30 ng/mL] status subjects. In subjects with IFG and T2DM (n=65), the vitamin D status was significantly inversely correlated both with oxLDL (r=-0.413, p=0.001) and AOPPs (r=-0.475, p<0.001), and strongly positively associated with highdensity lipoprotein cholesterol (r=0.609, p<0.001). CONCLUSIONS: In the elderly with impaired glucose metabolism the vitamin D status is inversely associated with levels of circulating markers of oxidative stress and endothelial dysfunction, especially in subjects with hypovitaminosis D.