Dihydroquercetin and biochaga reduce H2O2 induced DNA damage in peripheral blood mononuclear cells of obese women in vitro-a pilot study.

Systemic oxidative stress stemming from increased free radical production and reduced antioxidant capacity are common characteristics of obese individuals. Using hydrogen peroxide (H2O2) to induce DNA damage in vitro, in peripheral blood mononuclear cells (PBMCs) from obese subjects and controls, the DNA protective ability of dihidroqercetin (DHQ) and biochaga (B) alone or in combination, were evaluated. The effects of DHQ and B were estimated under two experimental conditions: pre-treatment, where cells were pre-incubated with the substances prior to H2O2 exposure; and post-treatment when cells were first exposed to H2 H2O2, and further treated with the compounds. DNA damage was evaluated using the comet assay. The results of pre- and post-treatment showed a significant decrease in DNA damage produced by H2O2 in the obese group. This decrease was not significant in control group probably due to a small number of subjects in this pilot study. More prominent attenuation was noted in the pre-treatment with DHQ (250 µg/mL). Analysis of antioxidant properties revealed that DHQ's remarkable reducing power, 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity, and potent ∙OH scavenging properties may contribute to strong attenuation of H2O2 induced DNA damage. Also, B showed strong reducing power, DPPH, and ∙OH scavenging ability, while reducing power and DPPH scavenger effects were increased in the presence of DHQ. Conclusively, DHQ and B may reduce H2O2-induced DNA damage in PBMCs from obese subjects when challenged in vitro, and could be valuable tools in future research against oxidative damage-related conditions.

Monitoring of the human serum albumin carbonylation level through determination of guanidino group content.

Carbonylation of the protein amino, guanidine, and thiol groups with α-oxoaldehydes (which are produced in higher quantities in diabetes, uremia, oxidative stress, aging, and inflammation) is one of the important causes of vascular complications. For monitoring of the human serum albumin (HSA) carbonylation level, a spectrophotometric method based on the formation of colored adduct between guanidine group and thymol-sodium hypobromite reagent in the alkaline medium was investigated. Beer's law is obeyed in the concentration range of Arg and protein guanidine groups from 1 to 40 mM. Precision of the method (relative standard deviation) was in the range of 0.9 to 2%. Accuracy was examined by the standard addition method (recovery ~100%). The method was applied for monitoring of the carbonylation level of HSA with methylglyoxal in vitro and of HSA isolated (using affinity chromatography) from sera of 21 patients with type 2 diabetes and 12 healthy persons. The content of guanidine groups in HSA isolated from diabetics (19.64 ± 1.07 mM/mM albumin) was significantly lower (P < 0.001) in comparison with a control group (21.87 ± 1.02 mM/mM albumin). The method is simple and fast, has good accuracy and precision, and is suitable for clinical practice as well for in vitro protein carbonylation experiments.

Comparative analysis of collagenase XI and liberase H1 for the isolation of human pancreatic islets.

BACKGROUNDS/AIMS: The aim of this study was to compare efficacy of two enzymes, Liberase HI and Collagenase XI in human adult pancreatic islet isolation. METHODOLOGY: Pancreatic tissue samples were digested either with Liberase HI or Collagenase XI, using a non-automated method. We investigated the effect of both enzymes on yield, function and percent viability of the islets. RESULTS: No significant differences were found regarding islet yield when comparing Liberase HI to Collagenase XI. Viability of Collagenase-isolated islets was initially lower, but following 3 days of culture they attained a higher viability than the Liberase treated islets. Although the stimulation index tended to be higher in the Liberase-isolated islets no significant differences were observed between the two enzymes, except on the first day of cultivation; SI values for all Liberase concentrations were significantly higher than for Collagenase (p < 0.05). CONCLUSIONS: We conclude that during the isolation procedure using Collagenase XI, the functional capacity of the isolated islets decline, but this is restored during a subsequent cultivation. On the other hand, during digestion with Liberase HI, the islets suffer less functional damage, resulting in better preservation of their functional capacity immediately after the isolation, as well as the subsequent 7 days of cultivation.

Homocysteine is a marker for metabolic syndrome and atherosclerosis.

BACKGROUND: It has been documented that patients with metabolic syndrome (MS) and vascular complications have higher homocysteine levels. Hyperhomocysteinemia correlates with IR, increasing oxidative stress, which causes lesions of vascular endothelium leading to endothelial dysfunction, hypertension and atherosclerosis. OBJECTIVE: The objectives of the study were to examine homocysteine values, along with cardiovascular risk factors (lipid and apolipoprotein status, CRP, blood pressure), indicators of renal function (microalbuminuria/24h), glucose regulation and insulin resistance (glucose and insulin level, HbA1c, HOMA-IR, uric acid) and anthropometric parameters (BMI, WC, HC, WHR) in patients with and without MS as a correlation between homocysteine and MS factors. METHODS: The study included obese and overweight individuals, aged of 30-75 yrs. classified into two groups: with MS (n=35) and without MS (n=41). RESULTS: Patients with MS had increased WC, BMI, BP, glycaemia, HOMA-IR, TG, CRP, microalbuminuria, homocysteine and decreased HDL-C (p<0.05). Statistically significant difference between groups was found for WC, BMI, sBP and dBP, TG, HDL-C (p<0.01) and glycaemia, CRP, Apo B, HOMA-IR (p<0.05). Significant positive correlations were found between homocysteine and sBP (p=0.036), dBP (p=0.04), Apo B (p=0.038) and hyperlipoproteinemia (type IIa, type IIb and type IV) (p=0.04). CONCLUSION: Patients with MS had increased abdominal obesity, hypertension, hypertriglyceridemia, inflammation factors, IR, homocysteine and microalbuminuria as markers of endothelial dysfunction. A correlation between homocysteine and hypertension and hyperlipoproteinemia showed that homocysteine could be used as a potential marker for atherosclerosis progression.

Method for monitoring of the protein amino group changes during carbonylation.

OBJECTIVES: Carbonylation of the protein amino, guanidino and thiol groups is one of the important causes of vascular complications in diabetes. We developed a simple spectrophotometric method for monitoring of the changes in the protein amino group contents during carbonylation. DESIGN AND METHODS: The method is based on the reaction of amino group with p-benzoquinone in the slightly alkaline media. It was applied during carbonylation in vitro with methylglyoxal and in vivo in 13 patients with type 2 diabetes and 20 healthy persons. RESULTS: The method is simple, fast, precise (RSD in the range of 1.2-1.8%) and accurate (recovery about 100%). The content of amino groups in human serum albumin isolated from diabetics was significantly lower (p<0.01) in comparison with a control group. CONCLUSION: The method developed is suitable for quantification of protein amino groups during in vitro carbonylation as well as for clinical practice.