IGFBP-3, a marker of cellular senescence, is overexpressed in human papillomavirus-immortalized cervical cells and enhances IGF-1-induced mitogenesis

Human ectocervical cells, following retroviral transduction with the human papillomavirus type 16 E6/E7 oncogenes, are altered in their array of transcribed cellular genes, including increased mRNA for the insulin-like growth factor binding protein 3 (IGFBP-3). IGFBP-3 expression is associated with cellular senescence, and its addition to many cell types inhibits growth or induces apoptosis. By immunoblotting and enzyme-linked immunosorbent assay methods, we demonstrate that late-passage, immortalized E6/E7-transduced cells secrete high levels of IGFBP-3 (25 ng/ml), which represent a 500-fold increase compared to levels in early-passage, nonimmortalized transduced cells (<0.05 ng/ml). Concomitantly, these late-passage cervical cells exhibit an increase in sensitivity to IGF-1, including enhanced phosphorylation of the IGF receptor (IGF-R) and insulin receptor substrate as well as increased DNA synthesis (5-fold) and cell proliferation (3.7-fold). However, there was no change in the level of IGF-R in these cells (surface or total), and the cells did not synthesize IGF-1, indicating that these arms of the IGF pathway were independently regulated and not responsible for the augmented signaling. Consistent with a causal relationship between IGFBP-3 expression and enhanced IGF-1 responses, we found that early-passage cells could be converted to the late-passage, IGF-1-responsive phenotype by preincubation with IGFBP-3. Thus, in contrast to findings with some cell types, IGFBP-3 expression in cervical cells is associated with augmented IGF-1 signaling and cell proliferation and correlates with the timing of cellular immortalization.     

Discordance Between Gh and Igf-1 Levels in Turkish Acromegalic Patients

Objective: Discordance between insulin-like growth factor-1 (IGF-1) and growth hormone (GH) levels is an important problem in the follow-up of patients diagnosed with acromegaly. Our aims were to evaluate the discordance between IGF-1 and GH levels and compare the performance of different cut-off levels for the nadir in GH (GHn) in acromegalic patients.Methods: The study included 63 acromegalic patients in a follow-up at a tertiary care university hospital facility. Levels of IGF-1, IGF binding protein-3 (IGFBP-3), and GH were investigated. The baseline GH and GHn levels were evaluated after an oral glucose tolerance test (cut-offs of 0.4 and 1 ng/mL, respectively). The discordance rates between GHn and IGF-1 levels, and IGF-1/IGFBP-3 ratios were determined.Results: We first adopted a GHn cut-off value of 1 ng/mL and found that 27 patients (42.9%) exhibited biochemical remission (BR) (IGF-1 <95^th percentile, GH <1), and 25 patients (39.7%) had no BR (NBR) (IGF-1 ≥95^th percentile, GH >1).Discordance in the presence of normal IGF-1 and nonsuppressed GH (DC1) occurred in 2 of 63 (3.2%) patients; discordance in the presence of high IGF-1 and suppressed GH (DC2) occurred in 9 of 63 (14.3%) patients. If the GHn cut-off value adopted was 0.4 ng/mL, the distributions were 17 of 63 (27.0%) patients in BR, 29 of 63 (46.0%) patients in NBR, 12 of 63 (19.0%) in DC1, and 5 of 63 (7.9%) patients in DC2. If only the baseline GH values were considered, the distributions were very similar to those with a GHn cut-off value of 0.4 ng/mL. The IGF-1/IGFBP-3 ratio was lowest in the BR group.Conclusion: Adopting a GHn cut-off value of 0.4 ng/mL did not increase the test performance compared with baseline GH only. In contrast, in the follow-up of acromegalic patients, the IGF-1/IGFBP-3 ratio might be a useful measurement when discordance between IGF-1 and GH levels occurs. We propose that these values be considered in clinical practice.Abbreviations:BR = biochemical remissionDC1 = discordance group 1DC2 = discordance group 2DM = diabetes mellitusGH = growth hormoneGHn = nadir in GHIGF-1 = insulin-like growth factor-1IGFBP-3 = IGF binding protein-3LAR = long-acting releaseNBR = not in biochemical remissionOGTT = oral glucose tolerance test     

Zinc supplementation increases the level of serum insulin-like growth factor-I but does not promote growth in infants with nonorganic failure to thrive

We investigated in a randomized double-blind placebo-controlled study the effects of zinc supplementation (2 mg/kg/day) for 12 weeks on growth, serum insulin-like growth factor-I (IGF-I) and insulin-like factor binding protein-3 (IGFBP-3) on 3- to 9-month-old infants with nonorganic failure to thrive (NOFTT). 25 infants completed the study, 14 received zinc supplementation (group A), and 11 received placebo (group B). The control group for baseline measurements was composed of 10 age-matched normal growing infants. There were no significant changes in weight for age, length for age, or weight for length during the entire study period in either group A or B. Serum IGF-I levels at baseline were similar in all the groups. After 12 weeks of therapy, serum IFG-I levels increased significantly only in the zinc-supplemented group, from 40.3 +/- 7 ng/ml at baseline to 65 +/- 8 ng/ml (p < 0.05). There was a marked difference in serum IGF-I levels between the zinc-supplemented group and the placebo group after 12 weeks: 65 +/- 8 vs. 49.4 +/- 5 ng/ml (p = 0.058, 95% CI of difference 9.88-21.31). No change was demonstrated in serum IGFBP-3 levels in either study group. We conclude that although zinc supplementation increased serum IGF-I levels, it did not improve the growth parameters of infants with NOFTT.     

Results of a two-year treatment with slow release lanreotide in acromegaly.

In this open sequential study we evaluated the long-term effectiveness and tolerability of the i.m. administration of slow release lanreotide 30 mg (SRL) in 18 acromegalics (7 M/11 F, age 50.9+/-12.7 yr). Baseline mean GH and IGF-1 levels were 15.8+/-6.6 ng/ml and 702+/-74 ng/ml, respectively. Four hours, 1, 7, and 14 days after SRL, mean GH levels were 8.9+/-5.9 (p < 0.005), 11.4+/-6.9 (p < 0.05), 9.1+/-4.5 (p < 0.05), and 9.1+/-4.1 ng/ml (p < 0.05), respectively; and the IGF-1 values at 1, 7, and 14 days were 624+/-77 (p < 0.05), 555+/-83 (p < 0.001), and 467+/-58 ng/ml (p < 0.0001), respectively. Four hours after SRL administration GH was < 2.5 ng/ml in 11 patients and decreased 85% of the basal value, without normalizing, in another case. In the following 2 weeks, 7 and 2 patients maintained GH < 2.5 ng/ ml or < 50% of baseline; 3 and 2 of them attained IGF-1 values in the normal range or < 50% of basal levels. A patient developed acute pancreatitis after the injection of the drug and therefore stopped the treatment. Another patient did not continue SRL, and she was turned on octreotide, s.c. administered (OCT), because only the latter treatment ameliorated significantly the headache. In 16/18 patients the treatment was continued until the 24th month. SRL was administered every 14 days until the 24th month in 3 cases, whereas in 13 patients the dose schedule was increased every 10 days since the 7th month because they did not normalize serum GH and IGF-1 levels. In these 16 patients baseline GH and IGF-1 levels were 10.0+/-2.5 ng/ml and 671+/-75 ng/ml, respectively. At the 1st, 3rd, and 6th month of treatment mean GH levels fell to 5.4+/-1.4 (p < 0.05), 5.3+/-1.8 (p < 0.05), and 5.0+/-1.6 (p < 0.05) ng/ml, respectively; and IGF-1 declined to 511+/-87 (p < 0.005), 565+/-85 (p < 0.05), and 525+/-94 (p < 0.01) ng/ml, respectively. Throughout the first semester GH was < 2.5 ng/ml in 5 patients and decreased > 50% in another three. IGF-1 levels normalized in 3/5. Throughout the following 18 months of treatment, mean GH (3.4+/-1.0 ng/ml) and IGF-1 (413+/-75 ng/ml) values decreased significantly in comparison with both the baseline concentrations (GH p < 0.01, IGF-1 p < 0.001) and the levels measured during the 1st semester of treatment (GH p < 0.05, IGF-1 p < 0.001). GH remained < 2.5 ng/ml in 11 patients, and in 8/11 cases IGF-1 fell in the normal range. Serum GH and IGF-1 levels decreased by more than 50% of baseline levels in 2 other cases. At MRI, pituitary adenoma was no longer evident in one patient previously treated with OCT and significantly decreased in another patient previously treated with surgery plus radiotherapy, as well as in a patient previously untreated. During treatment the percentage of patients complaining of headache and fatigue decreased significantly (chi2, p < 0.05 and p < 0.0005, respectively). Overall, the headache (p < 0.005), arthralgia (p < 0.05), and paresthesia (p < 0.01) ameliorated significantly. Ultrasound scan showed gallbladder sludge or sand-like stones in 5/11 patients. This study, which is one of the longest surveys on a relatively large series of acromegalics treated with SRL, confirms the long-term effectiveness of this drug for the treatment of patients with active acromegaly. SRL decreases significantly GH and IGF-1 in most cases and induces the shrinkage of the pituitary tumor in some patients previously either untreated or both treated for acromegaly. SRL improves significantly clinical symptoms and it is well tolerated.     

Increased insulin-like growth factor 1 activity can rescue KLE endometrial-like cells from apoptosis

BACKGROUND: The peritoneal fluid (PF) of women with endometriosis contains protease(s) activity able to hydrolyze insulin-like growth factor-binding protein 3 (IGFBP-3), increasing the bioavailability of insulin-like growth factor-1 (IGF-1) locally. Therefore, we characterized the effects of IGF-1 on KLE endometrial-like cells in vitro. MATERIALS AND METHODS: The mitogenic effect of IGF-1 was assessed by the analysis of the DNA content and cell count. Apoptosis was triggered experimentally by the 48 hr exposure of KLE cells to 100 nM of adriamycin in the presence and absence of IGF-1 (50 ng/ml). Adriamycin apoptosis of KLE cells was determined by the number of dead KLE cells using trypan blue exclusion and by the DNA fragmentation on simple agarose gel and flow cytometry of propidium iodide and HOECHST 33342-stained KLE cells using an EPICS 753 pulse cytometer. RESULTS: IGF-1 stimulated the growth of KLE cells in a dose-dependent manner (optimal dose of 50 ng/ml) and protected KLE cells from adriamycin (100 nM)-induced apoptosis. CONCLUSIONS: These data suggest that IGF-1 is a survival factor for KLE cells. Conceivably, increased IGF-1 activity in the PF can optimize both the survival and ectopic growth of endometrial cells in the peritoneal cavity.     

Influence of bicalutamide with or without tamoxifen or anastrozole on insulin-like growth factor 1 and binding proteins in prostate cancer patients

BACKGROUND: There is growing evidence that IGF-1 and binding proteins may be involved in prostate cancer promotion and progression. PATIENTS AND METHODS: IGF-1 and binding proteins (IGFBP-1 and 3) serum levels were measured at baseline and after 3 and 6 months of treatment in a selected group of patients with prostate cancer who were randomly assigned to treatment with bicalutamide, bicalutamide plus anastrozole or bicalutamide plus tamoxifen in a comparative study investigating the role of pharmacological medication in the development of bicalutamide-induced gynecomastia. RESULTS: Bicalutamide monotherapy does not appear to alter the IGF-1/IGFBP system. In fact, the increase in IGF-1 levels induced by this treatment was paralleled by comparable increases in binding protein (IGFBP-3). No major changes from baseline up to month 6 either in IGF-1 or in IGFBP-1 and 3 were observed in the bicalutamide plus anastrozole arm. The addition of tamoxifen to bicalutamide produced a sharp decrease in IGF-1 levels (p<0.001) coupled with an increase in both IGFBP-1 (p=0.001) and, to a lesser extent, IGFBP-3 (p=0.5). CONCLUSIONS: The concurrent administration of tamoxifen and bicalutamide reduces the synthesis and bioavailability of IGF-1. Moreover, increased binding protein levels might exert antiproliferative and proapoptotic effects on prostate cancer cells, independently of the IGF-1/IGF receptor-mediated survival system. Both effects might have a synergistic inhibitory influence on prostate cancer growth.     

Short-term effects of anastrozole treatment on insulin-like growth factor system in postmenopausal advanced breast cancer patients

Insulin-like growth factors (IGFs) play a fundamental role in cancer development by acting in both an endocrinal and paracrinal manner, and hormone breast cancer treatments affect the IGF system by modifying circulating growth factor levels. We evaluated total IGF-1, IGF-2, IGF binding protein (IGFBP)-1 and IGFBP-3 in the blood of 34 postmenopausal advanced breast cancer patients (median age 63 years, range 41–85) treated with anastrozole, a non-steroidal structure aromatase inhibitor (NSS-AI). The plasma samples were obtained at baseline, and after 2, 4, 8 and 12 weeks of treatment. The IGFs were quantitated by means of sensitive radioimmunoassays (RIAs). IGF-1 significantly increased during anastrozole treatment (baseline versus 12 weeks, P=0.031), IGF-2 showed a trend towards an increase, and IGFBP-1 constantly but not significantly decreased; IGFBP-3 did not seem to be affected at all. The anastrozole-induced changes in IGFs and IGFBP-1 appeared to be different in the patients receiving a clinical benefit from those observed in non-responders. We have previously shown that letrozole (a different type of NSS-AI) modifies blood IGF-1 levels, and the results of this study of the biological effects of anastrozole on the components of the IGF system confirm our previous observations.     

Synergistic inhibition of LDL oxidation by phytoestrogens and ascorbic acid

Increasing evidence indicates that oxidative modification of low-density lipoprotein (LDL) is an important determinant in atherogenesis, and following menopause, the incidence of coronary heart disease is as prevalent in women as it is in men. Estrogen has been demonstrated to inhibit the susceptibility of LDL to be oxidized, and more recently the use of phytoestrogens has been considered for estrogen replacement therapy. In this study the antioxidant activity of the three major phytoestrogens: genistein, daidzein, and equol were measured in terms of LDL oxidative susceptibility. Increasing levels of genistein, daidzein, and equol inhibited LDL oxidation, and this inhibitory effect was further enhanced in the presence of ascorbic acid. The synergism exhibited by these compounds is of clinical importance to phytoestrogen therapy since the efficacy of phytoestrogens as effective antioxidants is evident at concentration well within the range found in the plasma of subjects consuming soy products. However, this synergism, combined with the low reactivity of the phytoestrogens with peroxyl radicals, suggests that an antioxidant mechanism other then free radical scavenging reactions account for the phytoestrogen antioxidant effect. A structural basis for inhibition of LDL oxidation involving interaction of the phytoestrogens with apoB-100 is postulated.     

Synthesis and characterization of biotinylated forms of insulin-like growth factor-1: topographical evaluation of the IGF-1/IGFBP-2 AND IGFBP-3 interface

Activation of the insulin-like growth factor-1 (IGF)-1 receptor signaling pathways by IGF-1 and IGF-2 results in mitogenic and anabolic effects. The bioavailability of the IGFs is regulated by six soluble binding proteins, the insulin-like growth factor binding proteins (IGFBPs), which bind with approximately 0.1 nM affinity to the IGFs and often serve as endogenous antagonists of IGF action. To identify key domains of IGF-1 involved in the interaction with IGFBP-2 and IGFBP-3, we employed IGF-1 selectively biotinylated on residues Gly 1, Lys 27, Lys 65, and Lys 68. All monobiotinylated species of IGF-1 exhibited high affinity ( approximately 0.1-0.2 nM) for IGFBP-2 and IGFBP-3 in solid-phase-binding assays. However, different labeling intensities were observed in ligand blot analysis of IGFBP-2 and IGFBP-3. The N(epsilon)(Lys65/68)(biotin)-IGF-1 (N(epsilon)(Lys65/68b)-IGF-1) probe exhibited the highest signal intensity, while N(alpha)(Gly1b)-IGF-1 and N(epsilon)(Lys27b)-IGF-1 demonstrated significantly lower signals. When taken together, these results suggest that, once bound to IGFBP-2 or IGFBP-3, the biotin moieties of N(alpha)(Gly1b)-IGF-1 and N(epsilon)(Lys27b)-IGF-1 are inaccessible to NeutrAvidin-peroxidase, the secondary binding component. Ligand blots using IGF-1 derivatized with a long chain form of the N-hydroxysuccinimide biotin (NHS-biotin) to yield N(alpha)(Gly1)(LC-biotin)-IGF-1 and N(epsilon)(Lys27)(LC-biotin)-IGF-1 demonstrated increased signal intensity compared with their NHS-biotin counterparts. In BIAcore analysis, IGFBP-2 and IGFBP-3 bound only to the N(epsilon)(Lys65/68b)-IGF-1-coated flowcell of a biosensor chip, confirming the inaccessibility of Gly 1 and Lys 27 when IGF-1 is bound to IGFBP-2 and IGFBP-3. These data confirm the involvement of the IGFBP-binding domain on IGF-1 in binding to IGFBP-2 and IGFBP-3 and support involvement of the IGF-1R-binding domain in IGFBP binding.     

Relationships between IGF-1 and IGFBP-1 and adiposity in obese African-American and Latino adolescents

The purpose of this study was to examine interrelationships between insulin-like growth factor 1 (IGF-1), IGF binding proteins (IGFBPs), and adiposity in 49 African-American and 77 Latino obese adolescents (15.3 ± 0.1 and 15.4 ± 0.2 years; BMI: 33.0 ± 0.7 and 35.0 ± 1.0 kg/m(2), respectively). Immunoradiometric assays were used to measure IGF-1, IGFBP-1, and IGFBP-3. Total fat and soft lean tissue were measured by dual-energy X-ray absorptiometry and visceral adipose tissue (VAT), subcutaneous abdominal adipose tissue (SAAT), and hepatic fat fraction (HFF) were measured by magnetic resonance imaging. IGF-1 levels were 23.1% higher and IGFBP-1 were 40.4% higher in African Americans compared to Latinos after adjustment for total lean and total fat mass. IGF-1 and IGFBP-1 were inversely correlated with BMI, total fat mass, VAT, and HFF (r = -0.20 to -0.33, P < 0.05) while IGFBP-1 was inversely correlated with SAAT (r = -0.22, P < 0.05). These relationships did not differ by ethnicity, however, the relationship between IGF-1 and SAAT, as well as IGFBP-1 and HFF, differed by ethnicity. Predicted mean IGF-1 levels were 30.7% higher for African Americans at the 75th compared to 25th percentile of SAAT and only 11.7% higher for Latinos. Predicted mean IGFBP-1 levels were 158% higher for African Americans at the 25th compared to the 75th percentile of HFF while IGFBP-1 levels were 1.7% higher for Latinos at the 75th compared to the 25th percentile. These results demonstrate that the relationship between IGF-1 and SAAT as well as IGFBP-1 and HFF are different in African-American and Latino adolescents and may contribute to the higher IGF-1 levels in African-Americans.     

One-month strawberry-rich anthocyanin supplementation ameliorates cardiovascular risk,oxidative stress markers and platelet activation in humans

Strawberries are an important fruit in the Mediterranean diet because of their high content of essential nutrients and beneficial phytochemicals, which seem to exert beneficial effects in human health. Healthy volunteers were supplemented daily with 500 g of strawberries for 1 month. Plasma lipid profile, circulating and cellular markers of antioxidant status, oxidative stress and platelet function were evaluated at baseline, after 30 days of strawberry consumption and 15 days after the end of the study. A high concentration of vitamin C and anthocyanins was found in the fruits. Strawberry consumption beneficially influenced the lipid profile by significantly reducing total cholesterol, low-density lipoprotein cholesterol and triglycerides levels (−8.78%, −13.72% and −20.80%, respectively; P<.05) compared with baseline period, while high-density lipoprotein cholesterol remained unchanged. Strawberry supplementation also significant decreased serum malondialdehyde, urinary 8-OHdG and isoprostanes levels (−31.40%, −29.67%, −27.90%, respectively; P<.05). All the parameters returned to baseline values after the washout period. A significant increase in plasma total antioxidant capacity measured by both ferric reducing ability of plasma and oxygen radical absorbance capacity assays and vitamin C levels (+24.97%, +41.18%, +41.36%, respectively; P<.05) was observed after strawberry consumption. Moreover, the spontaneous and oxidative hemolysis were significant reduced (−31.7% and −39.03%, respectively; P<.05), compared to the baseline point, which remained stable after the washout period. Finally, strawberry intake significant decrease (P<.05) the number of activated platelets, compared to both baseline and washout values. Strawberries consumption improves plasma lipids profile, biomarkers of antioxidant status, antihemolytic defenses and platelet function in healthy subjects, encouraging further evaluation on a population with higher cardiovascular disease risk.     

4周有氧运动与饮食控制对肥胖女青少年血清IGF-1和IGF-1结合蛋白-3水平的影响

目的：研究4周中等强度有氧运动结合饮食控制对肥胖女青年、少年血清总胰岛素样生长因子1（IGF-1）、IGF-1结合蛋白3（IGFBP-3）水平和IGF-1活性的影响及其在体脂减少和糖脂代谢改善中的作用。方法：招募9名18~19岁肥胖女青年和30名14~16岁肥胖女少年,进行全封闭的4周中等强度有氧运动结合饮食控制干预。运动项目有游泳、跑步、健身操等,每周运动6 d,每天运动4 h,每运动30 min,休息5 min。运动强度从第1周的低强度（运动后即刻心率约100~120次/分）递增至第2~4周的中强度（运动后即刻心率约120~140次/分）。根据基础代谢率给予每日1 400或1 600 kcal的总能量。另招募正常体重女青年和女少年各9名作为对照组。检测肥胖女青年、少年在4周干预前、后和对照组女青年、少年的体重、身体质量指数（BMI）、腰围、空腹血糖、胰岛素和血脂水平以及血清总IGF-1和IGFBP-3的水平和IGF-1活性。结果：①与对照组相比,肥胖女青年、少年的血清总IGF-1和IGFBP-3水平均降低且肥胖女少年的IGF-1活性降低;②4周中等强度有氧运动结合饮食控制在显著降低肥胖女青年、少年的体脂、腰围和改善糖脂代谢的同时,降低血清IGFBP-3水平、增加IGF-1活性,但血清总IGF-1水平没有显著改变。且相关性分析显示IGF-1活性增加可能与肥胖女青年的腰围减少有关,但血清IGFBP-3水平的降低和IGF-1活性的增加与糖脂代谢的改善没有显著相关性。结论：4周中等强度有氧运动结合饮食控制降低肥胖女青年、少年的血清IGFBP-3水平、增加IGF-1活性;且IGF-1活性的增加可能与运动结合饮食控制降低肥胖女青年的腰围有关。     

Insulin-like growth factors and insulin-like growth factor binding proteins in adult patients with severe liver disease before and after orthotopic liver transplantation

INTRODUCTION: The liver is the main source of serum insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) and the concentration of these proteins might reflect liver function. METHODS: In a retrospective longitudinal study we examined serum levels of total and free IGF-I, IGF-II, IGFBP-1, IGFBP-2, IGFBP-3 and IGFBP-6 in 21 adult patients with end-stage liver disease before and after orthotopic liver transplantation (LTX) by sensitive and specific RIAs. In each patient, the mean value of at least three measurements before and after LTX was calculated. RESULTS: Before LTX, serum levels of total and free IGF-I, IGF-II, IGFBP-3 were low and showed a rapid and significant increase in almost all patients after successful LTX (total IGF-I: 30 +/- 7 vs. 256 +/- 30 ng/ml, p < 0.001; free IGF-I: 1.3 +/- 0.3 vs. 3.5 +/- 0.6 ng/ml, p < 0.01; IGF-II: 177 +/- 28 vs. 618 +/- 30 ng/ml, p < 0.001; IGFBP-3: 1,230 +/- 136 vs. 3,665 +/- 264 ng/ml, p < 0.001). In contrast, IGFBP-1 was found to be high immediately before LTX, and declined to normal levels after LTX (210 +/- 40 vs. 90 +/- 15 ng/ml, p < 0.01), while IGFBP-2 did not show any significant changes (1,154 +/- 296 vs. 1,303 +/- 192 ng/ ml). Positive correlations were found between IGF-I, IGF-II or IGFBP-3, and serum pseudocholinesterase (R = 0.50, 0.72 and 0.61 respectively, p < 0.001). Negative correlations were found between IGF-I, IGF-II or IGFBP-3, and prothrombin time (R = 0.50, 0.59 and 0.51 respectively, p < 0.001). CONCLUSION: Patients with severe liver disease show decreased levels of total and free IGF-I, IGF-II and IGFBP-3, and increased levels of IGFBP-1. These abnormalities are promptly normalized after successful LTX. Thus, serum levels of IGF-I, IGF-II and IGFBP-3 might be useful parameters for the assessment of liver function.     

Effect of One-Year Vitamin C- and E-Supplementation on Cerebrospinal Fluid Oxidation Parameters and Clinical Course in Alzheimer’s Disease

Antioxidant vitamins are being widely discussed as a therapeutic option in Alzheimer??s disease (AD). We recently found that supplementation with vitamin C and E over 1?month leads to an increase of their levels in cerebrospinal fluid (CSF) and a reduction of CSF lipid peroxidation. In the present study, we followed-up the biochemical and clinical effect of vitamin C and E supplementation in an open clinical trial over 1?year. Twelve AD patients stably taking a cholinesterase inhibitor were supplemented with vitamin C (1,000?mg/day) and E (400 I.U./day), while 11 patients taking cholinergic medication only served as a control group. Cognition was assessed at baseline, after 6 months and 12 months using the Mini-Mental State Examination; a more detailed testing of cognitive function was performed at baseline and after 12 months. From eight of the vitamin-supplemented patients, CSF was taken at baseline, after 1?month and after 1?year to measure the antioxidant effect of vitamin supplementation on CSF lipids using a recently established in vitro oxidation assay. CSF antioxidant vitamins were significantly increased after 1?month and 1?year of supplementation, while in vitro oxidation of CSF lipids was significantly reduced only after 1?year of the supplementation. The clinical course of AD did not significantly differ between the vitamin and the control group. We conclude that supplementation with vitamins E and C did not have a significant effect on the course of AD over 1?year despite of a limited antioxidant effect that could be observed in CSF.     

Serum IGF-1, IGFBP-3 and growth hormone levels in children with congenital heart disease: relationship with nutritional status, cyanosis and left ventricular functions

In this study we aimed to evaluate serum insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3) and growth hormone (GH) levels in children with congenital heart disease (CHD) and to determine if these parameters have any relationship to the cyanosis, nutritional status and the left ventricular systolic function. This study is prospective-randomized study which conducted in 94 CHD patients (36 girls and 58 boys, aged between one 1-192 months, 19 cyanotic CHD and 75 acyanotic CHD) and age-sex matched 54 children (26 girls and 28 boys) with no CHD. In the study group, 37 out of the 94 CHD patients (39.4%) and 16 out of the 54 controls (29.6%) had malnutrition. The difference between the cyanotic and acyanotic patients in respect to malnutrition was significant (57.9% and 34.6%, p<0.05). Serum IGF-1 levels were lower (41.8+/-3.9 microg/L, 106.9+/-17.9 microg/L respectively, p<0.001) and GH levels were higher (6.43+/-0.9 ng/ml, 3.87+/-0.5 respectively, p<0.05) in CHD patient group than the controls. Serum IGF-1 levels were significantly lower in cyanotic CHD patients than the acyanotic patients (17.2+/-3.2 microg/L, 48.7.0+/-4.6 microg/L respectively, p<0.001) and serum IGF-1 levels were both lower in acyanotic and cyanotic CHD patients than the controls (p<0.001 for both). Serum IGF-1 and GH levels were similar between the well-nourished CHD patients and CHD patients with malnutrition (p>0.05). In total study group, the most effective factors on serum IGF-1 levels was presence of CHD (p<0.001), in CHD patients, the presence of cyanosis is the most effective factor on serum IGF-1 level, the presence of malnutrition is the most effective factor on serum IGFBP-3 levels (p<0.01). In the acyanotic, cyanotic, and the entire CHD patient groups, we find no correlations between the serum IGF-1, IGFBP-3 levels and left ventricular systolic function measurements. But serum GH levels were negatively correlated with diastolic left ventricular interseptum diameter, diastolic left ventricular mass and left ventricular end-diastolic volume measurements in CHD patients. In conclusion, we determined that the most important factor on serum IGF-1 levels is cyanosis. Reduced IGF1 levels and decreased left ventricular mass with an elevated GH levels in CHD patients and these findings are prominent in the cases with cyanosis and malnutrition. For this reason we believe that chronic hypoxia plays a significant role in the pathogenesis of malnutrition and also we believe that IGF-1 deficiency seen in CHD patients may be responsible in the etiology of the decrease in left ventricular mass independently from GH.     

IGFBP-3 Inhibits the Proliferation of Neural Progenitor Cells

Insulin like growth factor-1 (IGF-1) plays an important role in the proliferation and differentiation of neural progenitor cells. The effects of IGF-1 can be regulated by insulin like growth factor binding protein-3 (IGFBP-3) which can either inhibit or stimulate the proliferation of cells depending on the expression of proteases that can release IGF-1 from IGF1-IGFBP3 complex. Although IGF-1 is essential for the development of brain, both IGFBP-3 and IGF-1 are elevated in the brains of children younger than 6 months of age. Likewise, IGFBP-3 is also upregulated following cerebral ischemia and hypoxia. However, the role of IGFBP-3 in neurogenesis is not clear. Using an in vitro culture system of rat neural progenitor cells, we demonstrate that IGFBP-3 specifically regulates the IGF-1 mediated neural progenitor cell proliferation via down regulation of phopho-Akt, and cyclin D1. In addition, IGFBP-3 also decreased the content of nestin in the neural progenitor cells indicating its potential role in neurogenesis.     

Performance and egg quality of laying hens fed flaxseed: highlights on n-3 fatty acids,cholesterol, lignans and isoflavones

Flaxseed is a rich source of α-linolenic acid and phytoestrogens, mainly lignans, whose metabolites (enterodiol and enterolactone) can affect estrogen functions. The present study evaluated the influence of dietary flaxseed supplementation on reproductive performance and egg characteristics (fatty acids, cholesterol, lignans and isoflavones) of 40 Hy-Line hens (20/group) fed for 23 weeks a control diet or the same diet supplemented with 10% of extruded flaxseed. The flaxseed diet had approximately three times the content of lignans (2608.54 ng/g) as the control diet, mainly secoisolariciresinol diglucoside (1534.24 v. 494.72 ng/g). When compared with the control group, hens fed flaxseed showed a similar deposition rate (72.0% v. 73.9%) and egg yield. Furthermore, there was no effect of flaxseed on the main chemical composition of the egg and on its cholesterol content. Estradiol was higher in the plasma of the control group (1419.00 v. 1077.01 pg/ml) probably due to the effect of flaxseed on phytoestrogen metabolites. The plasma lignans were higher in hens fed flaxseed, whereas isoflavones were lower, mainly due to the lower equol value (50.52 v. 71.01 ng/ml). A similar trend was shown in eggs: the flaxseed group had higher level of enterodiol and enterolactone, whereas the equol was lower (198.31 v. 142.02 ng/g yolk). Secoisolariciresinol was the main lignan in eggs of the flaxseed group and its concentration was three times higher then control eggs. Flaxseed also improved the n-3 long-chain polyunsaturated fatty acids of eggs (3.25 v. 0.92 mg/g egg), mainly DHA, however, its oxidative status (thiobarbituric reactive substances) was negatively affected. In conclusion, 10% dietary flaxseed did not affect the productive performance of hens or the yolk cholesterol concentration, whereas the lignans and n-3 polyunsaturated fatty acid content of eggs improved. Further details on the competition between the different dietary phytoestrogens and their metabolites (estrogen, equol, enterodiol and enterolactone) should be investigated.