Age-associated changes in Ca(2+)-ATPase and oxidative damage in sarcoplasmic reticulum of rat heart

Altered Ca(2+) handling may be responsible for the development of cardiac contractile dysfunctions with advanced age. In the present study, we investigated the roles of oxidative damage to sarcoplasmic reticulum (SR) and expression of Ca(2+)-ATPase (SERCA 2a) and phospholamban in age-associated dysfunction of cardiac SR. SR vesicles were prepared from hearts of 2-, 6-, 15-, and 26-month-old Wistar rats. Although activity of Ca(2+)-ATPase decreased with advancing age, no differences in relative amounts of SERCA 2a and phospholamban protein were observed. On the other hand, significant accumulation of protein oxidative damage occurred with aging. The results of this study suggest that age-related alteration in Ca(2+)-ATPase activity in the rat heart is not a consequence of decreased protein levels of SERCA 2a and phospholamban, but could arise from oxidative modifications of SR proteins. Cellular oxidative damage caused by reactive oxygen species could contribute to age-related alternations in myocardial relaxation.

Age-dependent effect of oxidative stress on cardiac sarcoplasmic reticulum vesicles

The oxidative stress hypothesis of aging suggests that accumulation of oxidative damage is a key factor of the alterations in physiological function during aging. We studied age-related sensitivity to oxidative modifications of proteins and lipids of cardiac sarcoplasmic reticulum (SR) isolated from 6-, 15- and 26-month-old rats. Oxidative stress was generated in vitro by exposing SR vesicles to 0.1 mmol/l FeSO4/EDTA + 1 mmol/l H2O2 at 37 degrees C for 60 min. In all groups, oxidative stress was associated with decreased membrane surface hydrophobicity, as detected by 1-anilino-8-naphthalenesulfonate as a probe. Structural changes in SR membranes were accompanied by degradation of tryptophan and significant accumulation of protein dityrosines, protein conjugates with lipid peroxidation products, conjugated dienes and thiobarbituric acid reactive substances. The sensitivity to oxidative damage was most pronounced in SR of 26-month-old rat. Our results indicate that aging and oxidative stress are associated with accumulation of oxidatively damaged proteins and lipids and these changes could contribute to cardiovascular injury.

[Factors modifying cord blood IgE levels - a pilot study]

AIM

The complex influence of internal and external environmental factors on the individual and his/her immune system and the lack of suitable markers to assess and reduce the risk of the development of allergies during the lifetime can explain the continuous increase in the number of people affected by some form of allergy. According to the results of some studies, cord blood IgE level could be a useful early marker for assessing the risk of atopic diseases, but the studies showed controversial results. In addition, several authors discuss the origin of these antibodies (synthesis in utero, peripartum contamination from maternal blood or placental transfer). The aim of our pilot study was to investigate the possible influence of modifying factors on cord blood IgE level.

MATERIAL AND METHODS

Our group of patients consisted of 184 retrospectively selected neonates (98 boys, 53.3% and 86 girls, 46.7%) from whom cord blood was collected and cord blood IgE level was measured 25 years ago (PRIST method). The impact of selected modifying factors (sex, type of delivery or month of birth) on cord blood IgE level was assessed retrospectively.

RESULTS

Higher cord blood IgE levels were found in boys than in girls, in neonates born by Caesarean section than in those born by natural delivery, and in those born in the winter months than in other seasons of the year. Our findings are in agreement with those of other authors.

CONCLUSION

Based on our results and those of others, we assume that the selected factors affect the cord blood IgE levels to varying degrees. These facts should be taken into consideration while interpreting the cord blood IgE levels.

[The possibility of the serum concentration of osteocalcin determination in lung cancer patients with suspected bone metastases]

AIM

The aim of this study was to compare serum levels of biochemical markers of bone metabolism - osteocalcin (OC) in correlation with bone metastases found during whole-body bone scintigraphy in patients with lung cancer.

MATERIAL AND METHODS

The serum levels of OC as a bone formation marker were determined in 60 patients (46 male, 14 female, mean age 66.65, range 50-84 years) with lung cancer (51 non-small-cell lung cancers - NSCLC and nine small-cell lung cancers - SCLC) and correlated with the presence of bone metastases detected by whole-body bone scintigraphy (hybrid system SPECT/CT: BrightView XCT, Philips Healthcare). Whole-body bone scintigraphy results were compared with OC for each patient with lung cancer and for person from control group of 10 persons (two males, eight females, mean age 52.3, range 34-67 years) with-out malignant disease.

RESULTS

By whole-body bone scintigraphy, bone metastases were found in 15 cases (25%), probably in 11 cases (18.33%) and 34 patients (56.67%) were without bone metastases out of 60 patients with lung cancer. The serum levels of OC were above reference range in five cases (8.33%) only with NSCLC and below reference range in 12 cases (20%) - in 10 cases in patients with NSCLC and in two cases in patients with SCLC. In control group of 10 persons, serum level of OC was below reference range only in one case.

CONCLUSION

The serum concentrations of osteocalcin were not correlated with findings performed bywhole-body bone scintigraphy in patients with lung cancer. Osteocalcin serum levels determination probably does not have diagnostic importance in lung cancer patients with suspected bone metastases.