Oxidative stress and reduced antioxidative status, along with endothelial dysfunction in acromegaly.

Acromegaly is characterized by high cardiovascular morbidity and mortality. Oxidative stress and endothelial dysfunction are underlying mechanisms of atherosclerosis.The aim of this study was to evaluate the blood redox status and endothelial function by means of nitric oxide (NO) levels in patients with acromegaly. Total antioxidant capacity (TAC), catalase activity and glutathione concentration (GSH), as measures of antioxidative capacity, total oxidized glutathione (GSSG) and thiobarbituric acid reactive substances (TBARS), as indices of oxidative stress, and NO levels were assessed in 15 patients with acromegaly (age 55.4±10.5 years; 6 males) and 15 age- and sex-matched controls (age 58.4±8.1 years; 7 males). Active disease was present in 12 patients: 11 on current pharmacotherapy and 1 newly diagnosed. Three acromegalics were in remission after successful treatment. Acromegalics as compared with controls had significantly lower levels of catalase activity (8.2±5.8 vs. 51.3±29.1 mmol/ml/min, p<0.001), GSH (0.97±0.54 vs. 1.41±0.35 mmol/l, p=0.006), GSSG (0.27±0.19 vs. 2.04±1.32 mmol/l, p=0.002) and NO levels (6.0±3.1 vs. 43.0±29.8 mmol/l, p<0.001), but higher TBARS (16.3±8.9 vs. 10.1±10.8, nmol/ml, p=0.019). After adjustment for confounders, differences in catalase activity, NO levels and TBARS remained significant (p=0.004, p<0.001 and p=0.025, respectively). No association between IGF-I/GH and oxidative stress markers was noticed, except for a positive correlation between nadir GH and GSSG (r²=0.563, p=0.036). Acromegaly is associated with increased levels of oxidative stress coupled by diminished antioxidant capacity and endothelial dysfunction indicated by the presence of decreased NO levels.

Associations of estrogen receptor alpha and beta gene polymorphisms with sex steroid levels and body fat content in men.

OBJECTIVE: Estrogens play an important role in male physiology. We investigated the possible association of four single nucleotide polymorphisms in Estrogen Receptor α ( ESR1) and Estrogen Receptor ß ( ESR2) genes with circulating levels of sex steroids and Sex Hormone Binding Globulin (SHBG) in men. DESIGN AND METHODS: SHBG, total and calculated free testosterone (TT and cal FT), estradiol (E2) and free Estradiol (FE2) were determined in a population-based cohort of 170 apparently healthy Greek men. Body mass index (BMI), waist circumference (WC) and percentage of body fat (%fat) content were measured in all participants. Genotyping for the PVU II and XBA I polymorphisms of the ESR1 gene and for the RSA I and ALU I polymorphisms of the ESR2 gene was performed. RESULTS: PVU II showed an association with E2 levels [median (IQR) pp 58.5 (42.1-73.4) pg/ml vs. Pp 48.8 (42.9-60.1) and PP 57.7 (44-70.5), p=0.032], and with %fat [mean±SD pp 24.6±5.3 vs. Pp 22.4±5.2 and PP 21.2±6.7, p=0.044], after adjustment for age and WC. Furthermore, the effect of PVU II on E2 was independent of %fat (p=0.038). A synergistic effect of the two ESR1 polymorphisms on E2 (p=0.023), FE2 (p=0.03) and %fat (p=0.004) was present. Finally, a synergistic effect of the ESR1 and ESR2 genes on TT (p=0.009), independent of age, WC and %fat also emerged. CONCLUSIONS: Genetic variation in ESR1 is associated with serum estradiol levels and body fat content regulation in men. Furthermore, a synergistic effect of ESR1 and ESR2 genes is exerted on serum testosterone levels.

Development of GC-MS/MS method with programmable temperature vaporization large volume injection for monitoring of 17ß-estradiol and 2-methoxyestradiol in plasma.

Monitoring of estradiol and its metabolites in biological samples is essential for the accurate diagnosis of a number of endocrine diseases. In this study, a sensitive, precise and specific GC-MS/MS method for the quantification of 17ß-estradiol (17-BE) and its main metabolite, 2-methoxyestradiol (2-MEOE), in plasma was developed and validated. Plasma concentrations of these steroids are currently investigated as diagnostic markers for pre-eclampsia, a systematic disorder of pregnancy and a leading cause of maternal and fetal morbidity and mortality worldwide. The method comprised treatment of the plasma sample by protein precipitation and subsequent isolation of steroids by solid phase extraction, derivatization of steroids by trifluoroacetic anhydride and GC-MS/MS analysis of the derivatized steroids. The large volume (10 µL) injection with the assistance of a Programmed Temperature Vaporization (PTV) injector in solvent split mode allowed a substantial increase in the sensitivity of the method. The ion trap MS was operated in optimized Product Ion Scan. By increasing the damping gas flow in the ion trap from the conventional 0.3 mL min(-1) to 2 mL min(-1), ion fragmentation was reduced and the instrument response was enhanced substantially. As a result, mass spectra with predominant molecular ions were acquired and molecular ions of the steroids of interest were used as precursor ions thus increasing specificity of the method. Under optimized GC-MS/MS conditions in product ion mode, the Limit of Detection (LOD) of the analyzed steroids ranged from 18.4 pg mL(-1) for 17-BE to 5.5 pg mL(-1) for 2-MEOE (S/N=3). The instrument response was linear in the investigated concentration range from 0.1 to 10 ng mL(-1) with R(2)>0.99 for 17-BE and 2-MEOE. The intra-batch accuracy obtained for quality control samples at the concentration levels of 0.1, 1, 3, 7 ng mL(-1) ranged from 94.9% to 109.9% for 17-BE and from 99.9% to 104.5% for 2-MEOE.

Effect of exogenous intermittent recombinant human PTH 1-34 administration and chronic endogenous parathyroid hormone excess on glucose homeostasis and insulin sensitivity.

We aimed to evaluate the effects of exogenous intermittent teriparatide (rhPTH 1-34) administration versus the chronic exposure to excess endogenous parathyroid hormone (PTH), as in pHPT, on glucose homeostasis. Two patient groups were studied: Group 1 included 25 normocalcemic women with postmenopausal osteoporosis (age 65.2+/-1.6 years) studied before and six months after teriparatide initiation; Group 2 included 19 postmenopausal women with pHPT (age 55.2+/-2.5 years) studied before and six months after successful parathyroidectomy. Calcium - total (Ca) and corrected (CCa) - ALP, PTH, as well as glucose and insulin concentrations during an oral glucose tolerance test (OGTT) were determined before and six months after either intervention. Area under the curve for glucose (AUCglu) and insulin (AUCins) were calculated. DeltaIns30'/DeltaGlu30' was applied as an index of insulin secretion. The HOmeostasis Model of Assessment (HOMA) and Matsuda ISI (Insulin Sensitivity Index) were used to calculate insulin resistance (IR) and whole body insulin sensitivity, respectively. In Group 1 no difference was found in any OGTT-derived parameter. In Group 2 significant reductions in AUCins and DeltaIns30'/DeltaGlu30' were observed. No correlation between the change in DeltaCCa or DeltaPTH and DeltaAUCglu or DeltaAUCins was found in either group. Our data suggest that while subtle transient alterations of Ca and PTH within the normal range as in exogenous rhPTH 1-34 administration do not affect glucose homeostasis, the continuously elevated Ca and endogenous PTH levels as in pHPT affect insulin sensitivity and result in increased insulin secretion.

Head-to-head comparison of risedronate vs. teriparatide on bone turnover markers in women with postmenopausal osteoporosis: a randomised trial.

AIMS: We aimed to compare the effect of risedronate (RIS) and teriparatide (TPTD) (recombinant human parathyroid hormone 1-34) on bone turnover markers in women with postmenopausal osteoporosis. METHODS: Forty-four Caucasian women (age 65.1 +/- 1.6 years) with postmenopausal osteoporosis were randomly assigned to receive either RIS 35 mg once weekly (n = 22) or TPTD 20 microg once daily (n = 22) for 12 months. Serum N-terminal propeptide of type 1 collagen (P1NP), C-terminal telopeptide of type 1 collagen (CTx), total alkaline phosphatase (ALP) and intact parathyroid hormone (iPTH) were obtained from all women before, 3 and 6 months after treatment initiation. Lumbar spine bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry before and 12 months after treatment initiation. RESULTS: P1NP, CTx and total ALP levels decreased in RIS group (p < 0.001) and increased in TPTD group (p < 0.001) throughout the treatment. iPTH increased significantly in RIS group (p < 0.05) and decreased in TPTD group (p < 0.001). Finally, lumbar spine BMD increased significantly in both RIS (p = 0.003) and TPTD groups (p < 0.001) without significant differences between them. CONCLUSIONS: Our data suggest that both serum P1NP and CTx are reliable markers of RIS and TPTD action in women with postmenopausal osteoporosis. In a similar way, serum total ALP can be used as an alternative marker for monitoring both RIS and TPTD action, while iPTH can be used only for TPTD-treated women. The increase in P1NP and CTx after 3 months of treatment with RIS or TPTD can predict the increase in BMD after 12 months of treatment.

Increased soluble E-selectin levels in type 2 diabetic patients with peripheral arterial disease.

AIM: Abnormal endothelial function is well known in patients with type 2 diabetes mellitus and thought to induce macroangiopathy. Increased levels of adhesion molecules have been found in type 2 diabetic patients and it has been suggested that they play an important role in the initiation of atherosclerosis. The aim of the present study was to clarify the relationship between objectively proven peripheral arterial disease (pAVD) and serum levels of soluble adhesion molecules in patients with type 2 diabetes mellitus. METHODS: Levels of soluble E-selectin, ICAM-1 and VCAM-1 were evaluated in 18 type 2 diabetic patients with pAVD assessed by Doppler ultrasound, in 19 type 2 diabetic patients and 22 non-diabetic subjects without pAVD. RESULTS: Soluble E-selectin levels were significantly increased in pAVD-diabetic patients compared to diabetics and non-diabetics without pAVD (78.7+/-29 vs 49.7+/-20.4 and 36+/-17 ng/ml respectively, p<0.001), while sICAM-1 and sVCAM-1 levels were comparable between the groups. No significant correlation was found between pAVD and adhesion molecule levels. Peripheral AVD was correlated with smoking (p=0.024), duration of diabetes (p=0.048) and microalbuminuria (p=0.041). Regression analysis revealed that only smoking (R=0.536, p=0.012) and glycosylated hemoglobin (R=0.435, p=0.036) were independent factors related to pAVD. Soluble ICAM-1 levels were significantly higher (p=0.041) in diabetic smokers with pAVD and sVCAM-1 (p=0.011) in patients with longer duration of diabetes. CONCLUSION: Type 2 diabetic patients with pAVD showed increased serum sE-selectin levels. No significant relationship was found between the presence or extent of pAVD and measured adhesion molecules. Our results suggest that sE-selectin reflects endothelial activation and is possibly involved in the atherogenesis process with the contribution of other factors that characterize the metabolic syndrome of diabetes.

Soluble adhesion molecules are not involved in the development of retinopathy in type 2 diabetic patients.

Raised serum levels of adhesion molecules are believed to reflect endothelial activation and may contribute to the development of diabetic vascular complications. The aim of this study was to clarify the association between soluble adhesion molecules levels and retinopathy in type 2 diabetic patients. Levels of soluble E-selectin, ICAM-1 and VCAM-1 were measured by enzyme-linked immunosorbent assay (ELISA) in 47 type 2 diabetic patients classified in two subgroups according to the presence (n=34) or absence (n=13) of retinopathy as determined by fundus ophthalmoscopy; 22 control subjects were also studied. Soluble E-selectin levels were significantly elevated in both diabetic subgroups compared to control subjects (p<0.01), while no significant difference was found in sICAM-1 and sVCAM-1 levels. However, sE-selectin, sICAM-1 and sVCAM-1 levels were comparable in diabetic subgroups. The progression of retinopathy was not associated with an increase in soluble adhesion molecules levels. Stepwise multiple regression analysis revealed that only diabetes duration and microalbuminuria were independent determinants of retinopathy (p<0.01). Our results confirm the contribution of endothelial activation in the development of diabetic complications as indicated by increased levels of soluble adhesion molecules. However, a direct implication of adhesion molecules in the pathogenesis or progression of type 2 diabetic retinopathy cannot be supported.

Hormone replacement therapy and breast cancer risk.

The female breast is subject to a lifetime of hormonal control. After menopause, breast tissue becomes quiescent when estrogens drop to low levels. Menopause-associated hormonal decreases produce short- and long-term consequences that can be treated successfully by hormone replacement therapy (HRT). Despite the beneficial effects of HRT, the potential risk of breast cancer is a concern of both women and physicians. The available data indicate that HRT administered for longer than 5 years moderately increases the risk of breast cancer, but overall the benefits outweight the potential risk.

Follicular fluid-induced acrosome reaction distinguishes a subgroup of men with unexplained infertility not identified by semen analysis.

We compared the ability of sperm to undergo follicular fluid-induced acrosome reaction in vitro in fertile men and patients with unexplained infertility. After capacitation under optimum conditions, 28% of sperm from fertile men undergo acrosome reaction after follicular fluid exposure, whereas only 7% of the cells react spontaneously. In 15 men with unexplained infertility, 6 patients showed lack of acrosome reaction, whereas 9 men had sperm acrosome reactions similar to that of fertile men. However, in this cohort under study, semen characteristics of AR(+) and AR(-) patients were similar. In addition to inducing sperm acrosome reaction, follicular fluid also promoted significant changes in motion characteristics of capacitated sperm. Sperm curvilinear velocity (Vc) increased significantly after exposure to follicular fluid though linearity remained unchanged. The largest difference in cumulative Vc occurred at 90 microns/s. Assessing the ability of capacitated sperm to acrosome react may have clinical significance in predicting whether such sperm are capable of fertilizing an ovum.

Low acrosin activity in a subgroup of men with idiopathic infertility dose not correlate with sperm density, percent motility, curvilinear velocity, or linearity.

The authors compared sperm acrosin activity with sperm density and cell motion characteristics in 21 normal fertile men and 25 patients with unexplained infertility. Under standardized and optimized conditions of abstinence and semen sample processing, we measured sperm acrosin activity in washed sperm from direct aliquots of semen and in aliquots of semen filtered through glasswool to remove dead cells and debris. Using washed sperm from semen, sperm acrosin levels in infertile men (median, 44 microIU/10(6) sperm) were significantly lower than values measured in fertile men (median, 67 microIU/10(6) sperm, P less than 0.01). After glasswool filtration, sperm acrosin activity was higher for both fertile and infertile men. Using washed sperm, 7 of 25 patients had acrosin activity consistently below values measured for fertile men; after glasswool filtration, values for 8 of 14 patients were below the normal range. For either fertile or infertile men, sperm acrosin activity showed no correlation with sperm density, percent motility, or either motion characteristic of curvilinear velocity (Vc40 microns/sec) or linearity (L3); and further, the low sperm acrosin activity of some infertile patients did not correlate with the motion co-characteristics measured at Vc40/L3, and the majority of patients with slower and/or less directional sperm had normal acrosin activity. From our data, we therefore conclude that sperm acrosin activity is independent of sperm motion characteristics.