Serum Follistatin Research Articles

Longitudinal analysis of maternal serum Follistatin concentration in normal pregnancy and preeclampsia.

Follistatin (FST) is a regulator of the biological activity of activin A (Act A), binding and blocking it, which could contribute to the modulation of its pro-inflammatory activity during pregnancy. We sought to investigate, in this nested case-control study, FST serum levels during normal pregnancy and correlate it with the FST profile in preeclamptic pregnant women, normal pregnant women followed 3months postpartum and eumenorrheic nonpregnant women throughout the menstrual cycle. Follistatin serum levels determined by ELISA, biochemical and anthropometric variables were measured in normal pregnant (n=28) and preeclamptic (n=20) women during three periods of gestation. In addition, FST serum levels were measured in a subset of normal pregnant women (n=13) followed 3months postpartum and in eumenorrheic nonpregnant women (n=20) during the follicular and luteal phases of the menstrual cycle. Follistatin serum levels in the eumenorrheic nonpregnant and postpartum group were significantly lower when compared to levels throughout gestation (P<0·01). Serum FST levels increased in each period of pregnancy analysed, being significantly higher towards the end of gestation (P<0·01). FST levels were lower in late pregnancy in preeclamptic women compared to normal pregnant women (P<0·05). Finally, FST levels were higher in the luteal phase when compared with the follicular phase of the menstrual cycle (P<0·05). These analyses would permit the consideration that changes in FST levels during pregnancy contribute to the control of the Act A system.

Pegylated Interferon-α Modulates Liver Concentrations of Activin-A and Its Related Proteins in Normal Wistar Rat.

Aims. To measure the expression of activin βA-subunit, activin IIA and IIB receptors, Smad4, Smad7, and follistatin in the liver and the liver and serum concentrations of mature activin-A and follistatin in normal rat following treatment with pegylated interferon-α (Peg-INF-α) and ribavirin (RBV). Materials and Methods. 40 male Wistar rats were divided equally into 4 groups: “control,” “Peg-only” receiving 4 injections of Peg-INF-α (6 µg/rat/week), “RBV-only” receiving ribavirin (4 mg/rat/day) orally, and “Peg & RBV” group receiving both drugs. The expression of candidate molecules in liver was measured by immunohistochemistry and quantitative PCR. The concentrations of mature proteins in serum and liver homogenate samples were measured using ELISA. Results. Peg-INF-α ± RBV altered the expression of all candidate molecules in the liver at the gene and protein levels (P < 0.05) and decreased activin-A and increased follistatin in serum and liver homogenates compared with the other groups (P < 0.05). There were also significant correlations between serum and liver activin-A and follistatin. Conclusion. Peg-INF-α modulates the hepatic production of activin-A and follistatin, which can be detected in serum. Further studies are needed to explore the role of Peg-INF-α on the production of activins and follistatin by the liver and immune cells.

O-004 Serum Follistatin In Girls With Pubertal Hyperandrogenism

The aim of the study was to examine the serum follistatin level in adolescent girls with hyperandrogenism (HA) and its possible role in the development of ovarian dysfunction. Methods Follistatin, follicle-stimulating hormone (FSH), estradiol (E 2 ) were studied in serum of 42 adolescent girls aged 15–17 years with different clinical symptoms of HA (acne, hirsutism) and irregular menstrual cycle (IMC), 42 patients with regularmenstrual cycle (RMC) and 30 healthy adolescents. Results Hyperandrogenic patients with IMC showed an increased follistatin secretion (p? =0,03) compared to a group with RMC and control group. This fact points to the involvement of this glycoprotein in the pathogenesis of ovarian dysfunctionin girls’ puberty. Also we found significant negative correlation between the levels of FSH and follistatin (p = 0,02) that proved the inverse relationship between secretion of gonadotropins and follistatin level. Besides the negative correlation between follistatin and E 2 has been revealed (p = 0,04). Conclusions It may be difficult to distinguish biologically and ultrasonically hyperandrogenic adolescents as the result of normalmaturational process of puberty from the ones with developing polycystic ovarian syndrome (PCOS). The increased secretion of follistatin and its correlation with the reduction of FSH and estradiol in adolescent girls with menstrual irregularities and hyperandrogenism confirms the pathological role of this intraovarian factor in discoordination of peripheral functioning of reproductive system, and its possible significance in pathogenesis of PCOS as a future outcome of pubertal hyperandrogenism.

Regulation and actions of activin A and follistatin in myocardial ischaemia–reperfusion injury

Activin A, a member of the transforming growth factor-β superfamily, is stimulated early in inflammation via the Toll-like receptor (TLR) 4 signalling pathway, which is also activated in myocardial ischaemia–reperfusion. Neutralising activin A by treatment with the activin-binding protein, follistatin, reduces inflammation and mortality in several disease models. This study assesses the regulation of activin A and follistatin in a murine myocardial ischaemia–reperfusion model and determines whether exogenous follistatin treatment is protective against injury. Myocardial activin A and follistatin protein levels were elevated following 30min of ischaemia and 2h of reperfusion in wild-type mice. Activin A, but not follistatin, gene expression was also up-regulated. Serum activin A did not change significantly, but serum follistatin decreased. These responses to ischaemia–reperfusion were absent in TLR4−/− mice. Pre-treatment with follistatin significantly reduced ischaemia–reperfusion induced myocardial infarction. In mouse neonatal cardiomyocyte cultures, activin A exacerbated, while follistatin reduced, cellular injury after 3h of hypoxia and 2h of re-oxygenation. Neither activin A nor follistatin affected hypoxia-reoxygenation induced reactive oxygen species production by these cells. However, activin A reduced cardiomyocyte mitochondrial membrane potential, and follistatin treatment ameliorated the effect of hypoxia-reoxygenation on cardiomyocyte mitochondrial membrane potential. Taken together, these data indicate that myocardial ischaemia–reperfusion, through activation of TLR4 signalling, stimulates local production of activin A, which damages cardiomyocytes independently of increased reactive oxygen species. Blocking activin action by exogenous follistatin reduces this damage.

Effects of chronic hepatitis C genotype 1 and 4 on serum activins and follistatin in treatment naïve patients and their correlations with interleukin-6, tumour necrosis factor-α, viral load and liver damage.

The importance of activins and follistatin in liver diseases has recently emerged. The aim of the present study was to measure the influence of chronic infection with viral hepatitis C (CHC) genotype 1 and 4 on serum levels of activin-A, activin-B and follistatin, and to determine their correlations with viral load, liver damage, interleukin-6 (IL-6) and tumour necrosis factor (TNF)-α. Sera samples collected from 20 male and 20 female treatment naïve CHC genotype 1 and 4 Saudi patients (ten males and ten females for each genotype), and 40 gender- and age-matched healthy participants were analysed for activin-A, activin-B and follistatin using enzyme-linked immunosorbent assay and their levels were correlated with IL-6, TNF-α, viral load and AST platelet ratio index (APRI). Serum activin-A, activin-B, IL-6 and TNF-α were significantly increased, while serum follistatin was significantly decreased, in both genders of CHC patients compared with control subjects, In both viral genotypes, activin-A was strongly and positively correlated with the viral load, APRI, IL-6 and TNF-α, and negatively with albumin (P<0.01). Activin-B showed the same correlations of activin-A only in CHC genotype 1 patients, but it was weaker than activin-A. No correlation was detected with follistatin. Serum activins, particularly activin-A, and follistatin are significantly altered by CHC genotype 1 and 4. This dysregulation of activins/follistatin axis may be associated with viral replication, host immune response and liver injury. Further studies are needed to illustrate the definite role(s) and clinical value of activins and follistatin in CHC.

The effect of rate of weight reduction on serum myostatin and follistatin concentrations in competitive wrestlers.

To evaluate anthropometric measures and serum markers of myostatin-pathway activity after different weight-reduction protocols in wrestlers. Subjects were randomly assigned to a gradual-weight-reduction (GWR) or rapid-weight-reduction (RWR) group. Food logs were collected for the duration of the study. Anthropometric measurements and serum samples were collected after an 8-h fast at baseline and after the weight-reduction intervention. Subjects reduced body mass by 4%. The GWR group restricted calories over 12 d, while the RWR group restricted calories over 2 d. A series of 2×5 repeated-measures (RM) ANOVAs was conducted to examine differences in nutrient consumption, while separate 2×2 RM ANOVAs were conducted to examine differences in anthropometric measures and serum markers. When applicable, Tukey post hoc comparisons were conducted. Significance for all tests was set at P<.05. There were no between-groups differences for any anthropometric measure (P>.05). Subjects in both groups experienced a significant reduction in body mass, fat mass, lean mass, and percent body fat (P<.05). There were no between-groups differences in serum markers of myostatin-pathway activity (P>.05), but subjects in the RWR condition experienced a significant increase in serum myostatin (P<.01), a decrease in follistatin (P<.01), and an increase in myostatin-to-follistatin ratio (P<.001). Although there were no between-groups differences for any outcome variables, the serum myostatin-to-follistatin ratio was significantly increased in the RWR group, possibly signaling the early stages of skeletal-muscle catabolism.

Serum activin A and follistatin levels in gestational diabetes and the association of the Activin A-Follistatin system with anthropometric parameters in offspring.

ContextThe Activin A-Follistatin system has emerged as an important regulator of lipid and glucose metabolism with possible repercussions on fetal growth.ObjectiveTo analyze circulating activin A, follistatin and follistatin-like-3 (FSTL3) levels and their relationship with glucose metabolism in pregnant women and their influence on fetal growth and neonatal adiposity.Design and methodsA prospective cohort was studied comprising 207 pregnant women, 129 with normal glucose tolerance (NGT) and 78 with gestational diabetes mellitus (GDM) and their offspring. Activin A, follistatin and FSTL3 levels were measured in maternal serum collected in the early third trimester of pregnancy. Serial fetal ultrasounds were performed during the third trimester to evaluate fetal growth. Neonatal anthropometry was measured to assess neonatal adiposity.ResultsSerum follistatin levels were significantly lower in GDM than in NGT pregnant women (8.21±2.32 ng/mL vs 9.22±3.41, P = 0.012) whereas serum FSTL3 and activin A levels were comparable between the two groups. Serum follistatin concentrations were negatively correlated with HOMA-IR and positively with ultrasound growth parameters such as fractional thigh volume estimation in the middle of the third trimester and percent fat mass at birth. Also, in the stepwise multiple linear regression analysis serum follistatin levels were negatively associated with HOMA-IR (β = −0.199, P = 0.008) and the diagnosis of gestational diabetes (β = −0.138, P = 0.049). Likewise, fractional thigh volume estimation in the middle of third trimester and percent fat mass at birth were positively determined by serum follistatin levels (β = 0.214, P = 0.005 and β = 0.231, P = 0.002, respectively).ConclusionsCirculating follistatin levels are reduced in GDM compared with NGT pregnant women and they are positively associated with fetal growth and neonatal adiposity. These data suggest a role of the Activin-Follistatin system in maternal and fetal metabolism during pregnancy.

Serum Activins and Follistatin during the Treatment of Chronic Hepatitis C Genotypes 1 and 4 and Their Correlations with Viral Load and Liver Enzymes: A Preliminary Report.

Aims. To measure the effect of pegylated interferon-α therapy on serum activin-A, activin-B, and follistatin and their correlation with viral load and liver fibrosis in chronic hepatitis C (CHC). Methods. This study was cross-sectional and sera were collected from 165 participants classified into 7 groups: 40 healthy negative control, 33 treatment naïve patients as positive control, 19 patients at week 4, 22 at week 12, and 19 at week 24 of treatment initiation and 21 responders and 11 nonresponders at the end of 48-week treatment protocol. Serum candidate proteins were measured using ELISA and liver fibrosis was assessed by AST platelet ratio index (APRI). Results. CHC significantly increased activins and decreased follistatin compared to negative control (P < 0.05). Activin-A and follistatin levels returned to the levels of negative control group at weeks 4, 12, and 24 following treatment initiation and were significantly different from positive control (P < 0.05). Both proteins were significantly different between responders and nonresponders. Activin-A correlated positively and significantly with the viral load and APRI. Conclusion. CHC modulates serum activin-A and follistatin and they appear to be influenced by pegylated interferon-α therapy. Further studies are needed to explore the role of activins in CHC.

Prognotic impact of serum follistatin in patients with hepatocellular carcinoma

Follistatin (FST) is a glycoprotein expressed in most organs, which interacts with activins or other members of the transforming growth factor beta family. Recently, several reports have shown that FST regulates a variety of processes during tumor progression. Here, serum FST in patients with liver diseases was measured, and its clinical utility as a biomarker was assessed. Serum was collected from 162 patients (91 hepatocellular carcinoma [HCC], 43 liver cirrhosis, and 28 chronic hepatitis) as well as from 16 healthy volunteers. FST was quantified by enzyme-linked immunosorbent assays, and levels were compared with clinical parameters including survival of the HCC patients. Median serum FST levels in HCC, liver cirrhosis, chronic hepatitis, and healthy volunteers were 1168, 1606, 1324, and 1661 pg/mL, respectively, not significantly different. In HCC patients, higher serum FST was associated with greater age, hepatitis C virus antibody-negativity, large tumor size, g-glutamyl transpeptidase, des-gamma carboxyprothrombin and presence of portal vein tumor thrombus. Survival of HCC patients with high FST levels was significantly shorter than for those with low levels (P = 0.004). Multivariate analysis revealed that in addition to large tumor size and presence of portal vein thrombus, high FST levels were independently correlated with poor prognosis (hazard ratio = 2.41, 95% confidence interval = 1.16-5.00, P = 0.02). Serum FST levels are significantly associated with HCC prognosis and could represent a predictive biomarker in this disease.

Umbilical Vein and Maternal Serum Inhibin A, Activin A, and Follistatin Concentrations in IUGR due to Placental Dysfunction Pregnancies

The objective of this study were to (1) quantify the concentrations of inhibin A, activin A, and follistatin in maternal serum and umbilical vein (inhibin A, activin A) in IUGR due to placental dysfunction pregnancies and control group, (2) determine the concentration differences of these factors in maternal and umbilical vein serum in control and subject group, and (3) examine the relationship between fetal growth and placental function. Sandwich ELISA was used to measure the concentrations in control (n=40) and subject groups (n=30). Umbilical vein serum inhibin A, activin A concentrations were increased in subject group compared with controls (inhibin A regression coefficient, 0.7647, P<0.001, activin A P<0.0005). Maternal serum inhibin A, activin A were significantly increased in subject group compared with controls (inhibin A regression coefficient, 0.7614, P<0.001, activin A P<0.0005). Maternal serum activin: follistatin ratio was significantly increased in subject group compared with controls (P<0.0005). Maternal serum inhibin A, activin A concentrations were more when compared to the umbilical vein inhibin A, activin A concentrations in subject group. The present study strengthens the evidence of using inhibin A, activin A, and follistatin as serum markers in routine screening for early detection of IUGR. But large prospective studies are needed to further define their role in clinical practice.

High Serum Levels of Follistatin in Patients with Ovarian Cancer

This study investigated the potential use of serum follistatin (FST) as a marker for ovarian cancer alongside serum cancer antigen-125 (CA-125). Serum samples were collected from patients with ovarian cancer (n = 45), benign ovarian cysts (n = 40) or other cancers (n = 100) and from healthy subjects (n = 60) for the determination of FST and CA-125 levels using enzyme-linked immunosorbent assays. Expression of FST in ovarian tissue was investigated using immunohistochemical staining. Compared with healthy subjects and patients with benign ovarian cysts, serum FST and CA-125 levels were significantly increased in patients with ovarian cancer. Using the 95% confidence interval for the healthy subjects group as the cut-off value, tumour marker sensitivity and specificity in ovarian cancer were 53.3% and 97% for FST and 77.8% and 84% for CA-125, respectively. Tissue expression of FST protein was more pronounced in ovarian cancer than in normal ovary. The serum FST level was elevated in the peripheral blood of patients with ovarian cancer and has potential as a tumour marker for ovarian cancer diagnosis. It may be particularly useful when combined with CA-125 detection to reduce the number of false-positive results.

Diagnostic value of serum activin A and follistatin levels in women with peritoneal, ovarian and deep infiltrating endometriosis

Activin A is a growth factor, produced by the endometrium, whose actions are modulated by the binding protein follistatin. Both proteins are detectable in the peripheral serum and their concentrations may be increased in women with endometriosis. The present study was designed to evaluate whether serum levels of activin A and follistatin are altered, and therefore have a potential diagnostic value, in women with peritoneal, ovarian and deep infiltrating endometriosis. We performed a multicenter controlled study evaluating simultaneously serum activin A and follistatin concentrations in women with and without endometriosis. Women with endometriosis (n = 139) were subdivided into three groups: peritoneal endometriosis (n = 28); ovarian endometrioma (n = 61) and deep infiltrating endometriosis (n = 50). The control group (n = 75) consisted of healthy women with regular menstrual cycles. Blood samples were collected from a peripheral vein and assayed for activin A and follistatin using commercially available enzyme immunoassay kits. The ovarian endometrioma group had serum activin A levels significantly higher than healthy controls (0.22 ± 0.01 ng/ml versus 0.17 ± 0.01 ng/ml, P < 0.01). None of the endometriosis groups had serum follistatin levels which were significantly altered compared with healthy controls; however, levels found in the endometrioma group (2.34 ± 0.32 ng/ml) were higher than that in the deep endometriosis group (1.50 ± 0.17 ng/ml, P < 0.05). The area under the receiver operating characteristic curve of activin A was 0.700 (95% confidence interval: 0.605-0.794), while that of follistatin was 0.620 (95% confidence interval: 0.510-0.730) for the diagnosis of ovarian endometrioma. The combination of both markers into a duo marker index did not improve significantly their diagnostic accuracy. The present study demonstrated that serum activin A and follistatin are not significantly altered in peritoneal or deep infiltrating endometriosis and have limited diagnostic accuracy in the diagnosis of ovarian endometrioma.

High Levels of Maternal Serum IL‐17 and Activin A in Pregnant Women Affected by Systemic Lupus Erythematosus

To evaluate changes of serum IL-17, activin A, follistatin, and other cytokines during pregnancy in women with systemic lupus erythematosus (SLE). A group of patients with SLE and controls were longitudinally studied, collecting a blood sample before and during three trimesters of pregnancy. Serum activin A, follistatin, IL-17, IL-6, IL-10, and TNF-α concentrations were evaluated by specific ELISA. Before pregnancy, while serum IL-17, IL-6, IL-10, and TNF-α resulted significantly higher in women with SLE (P<0.001), activin A and follistatin were not changed. Serum IL-17 concentrations were higher in SLE than in controls with no changes during pregnancy. IL-6 increased in both groups, resulting higher in SLE than in controls only in the first trimester (P<0.05). IL-10 concentration in SLE increased during pregnancy resulting significantly higher than in controls (P<0.01). TNF-α levels were higher in SLE than in controls in third trimester (P<0.01). Serum activin A levels in SLE were significantly higher than in controls (P<0.001) at third trimester. Women with SLE show increased secretions of activin A, IL-17, IL-6, IL-10, and TNF-α during gestation, with a different trend for the various cytokines. These data suggest that patients with SLE have a hyper-reactive immune system, probably receiving a placental contribution.

Serum follistatin in patients with prostate cancer metastatic to the bone

The clinical significance of circulating follistatin (FLST), an inhibitor of the multifunctional cytokine activin A (Act A), was investigated in patients with prostate cancer (PCa). The serum concentrations of this molecule were determined by an enzyme-linked immunosorbent assay (ELISA) in PCa patients with (M+) or without (M0) bone metastases, in patients with benign prostate hyperplasia (BPH) and in healthy subjects (HS). The effectiveness of FLST in detecting PCa patients with skeletal metastases was determined by the receiver operating characteristic (ROC) curve analysis. Serum FLST was significantly higher in PCa patients than in BPH patients (P=0.001) or HS (P=0.011). Conversely, in BPH patients, FLST levels resulted lower than in HS (P=0.025). In cancer patients the serum concentrations of FLST significantly correlated with the presence of bone metastases (P=0.0005) or increased PSA levels (P=0.04). Interestingly, significant differences in the ratio between FLST and Act A serum concentrations (FLST/Act A) were observed between HS and BPH patients (P=0.001) or PCa patients (P=0.0005). Finally, ROC curve analysis, highlighted a sound diagnostic performance of FLST in detecting M+patients (P=0.0001). However, the diagnostic effectiveness of FLST did not result significantly superior to that of Act A or PSA. These findings suggest that FLST may be regarded as a potential, molecular target in the treatment of metastatic bone disease while its clinical role as soluble marker in the clinical management of PCa patients with bone metastases needs to be better defined.

High serum follistatin levels in women with ovarian endometriosis

High serum follistatin levels in women with ovarian endometriosis

High serum follistatin levels in women with ovarian endometriosis

Follistatin is an activin-binding protein produced by several tissues, including endometrium and endometriotic implants. We aimed to quantify follistatin in patients with ovarian endometriosis and investigate its value as a diagnostic marker. Women undergoing laparoscopic excision of ovarian endometrioma (n = 52) or other benign ovarian cysts (n = 52) were studied, plus women with non-ovarian endometriosis (n = 11) and healthy controls (n = 27). Serum was collected from all subjects, and peritoneal and cystic fluid from a subset with endometrioma. Follistatin was measured by enzyme-linked immunosorbent assay. The diagnostic accuracy of follistatin to detect endometrioma was evaluated by receiver operating characteristic (ROC) curve and compared with cancer antigen (CA)-125. Serum follistatin was increased in women with ovarian endometrioma (2080 +/- 94 pg/ml) compared with controls (545 +/- 49 pg/ml, P < 0.001), other benign ovarian cysts (795 +/- 60 pg/ml, P < 0.001) or non-ovarian endometriosis (1271 +/- 115 pg/ml, P < 0.001). Cystic fluid showed a higher concentration of follistatin (9850 +/- 4461 pg/ml) than peritoneal fluid (1885 +/- 261 pg/ml, P < 0.001) and serum (P < 0.001). Follistatin levels detected 48/52 cases of endometrioma (92% sensitivity) at 1433 pg/ml cut-off, corresponding to 92% specificity. CA-125 detected only 44% of endometriomas with 90% specificity. ROC curve comparison showed follistatin was more accurate than CA-125 to discriminate women with endometrioma either from controls or women with other benign ovarian cysts (P < 0.0001). Serum follistatin is increased in women with endometriosis and allows clear distinction between endometrioma and other benign ovarian cysts. Follistatin has the sensitivity and specificity to become a useful clinical marker of ovarian endometrioma.

Adiponectin elevates activin A and reduces follistatin via the adiponectin receptor 2 in primary human hepatocytes

Aims: Adiponectin is believed to exert hepatoprotective effects and therefore it was analysed whether this adipokine may alter activin A or its natural inhibitor follistatin, both important in liver regeneration. Methods: Primary human hepatocytes were incubated with 10µg/ml recombinant adiponectin for 24h. Activin A and follistatin were measured in the supernatants by ELISA. Patients were examined with high-end ultrasound equipment and were subdivided into three groups: no steatosis: no difference in renal and hepatic echo-pattern (29 patients), low grade steatosis: slightly increased hepatic echogenicity (19 patients), advanced steatosis: strongly increased hepatic echogenicity (12 patients). Results: Adiponectin upregulated activin A mRNA and protein and simultaneously reduced follistatin mRNA and protein in primary human hepatocytes. Hepatocytic cell lines had a reduced activin A/follistatin ratio when compared to primary hepatocytes and neither activin A nor follistatin were altered by adiponectin incubation. Knock-down of the adiponectin receptor 1 (AdipoR1) or 2 (AdipoR2) by small-interfering RNA indicated that the latter is involved in adiponectin stimulated alterations of the activin A/follistatin system. However, inhibition of PPARa, that is activated via AdipoR2, did not disrupt the effects of adiponectin. Palmitic acid and oleic acid impaired adiponectin-mediated induction of activin A whereas follistatin was still repressed by adiponectin in the hepatocytes. Activin A, but not follistatin serum levels, were reduced in patients with advanced hepatic steatosis. Conclusion: The current study provides evidence that adiponectin alters activin A and follistatin in hepatocytes. Therefore, activin A and follistatin may not only be involved in liver regeneration after injury but also in fatty liver disease, a hypothesis that is in accordance with reduced systemic activin A levels in patients with advanced hepatic steatosis.

Embryonic overexpression of Galgt2 inhibits skeletal muscle growth via activation of myostatin signaling

Many proteins that affect skeletal muscle growth are secreted glycoproteins, yet the nature of how glycosylation regulates the expression and growth-promoting properties of such factors is not well understood. One type of glycosylation that affects muscle growth is that controlled by the CT GalNAc transferase (Galgt2), the enzyme responsible for the synthesis of the beta1,4GalNAc linkage on the CT carbohydrate antigen (GalNAcbeta1,4[Neu5Ac(or Gc)alpha2,3]Galbeta1,4GlcNAcbeta-R). In the mouse, both Galgt2 protein and the CT carbohydrate become confined to the neuromuscular synapse in skeletal muscle by the second postnatal week. Galgt2 transgenic mice that overexpress the CT carbohydrate from embryonic time-points onward in skeletal muscle had profoundly impaired muscle growth that was maintained throughout adulthood. Transgenic overexpression of Galgt2 increased myostatin protein expression and stimulated myostatin signaling, whereas expression of follistatin protein, a myostatin inhibitor, was decreased. Changed myostatin and follistatin protein levels were controlled at a posttranslational level, and inhibition of muscle growth was overcome if serum follistatin levels were normalized to wild-type levels. In contrast to embryonic Galgt2 overexpression, postnatal overexpression of Galgt2 had no effect on either myostatin or follistatin expression or muscle growth. These experiments demonstrate that Galgt2 can control growth by modulating the expression of myostatin and myostatin inhibitors during particular periods of muscle development.

222. A new role for activin in endometrial restoration after menses

10% of Australian women suffer from abnormal uterine bleeding (AUB). To stop endometrial bleeding after menstruation, the endometrium must repair adequately. We propose that endometrial restoration after menstruation has characteristics of wound healing and that inadequate endometrial repair may result in AUB. In vivo studies support a contribution of activins to skin wound healing: in mice overexpressing activins' natural inhibitor, follistatin, wound healing is significantly delayed (1). We hypothesised that activin would enhance endometrial repair and examined its contribution using an in vitro wound healing model and our well characterised in vivo mouse model of endometrial breakdown and repair (2). For the in vitro model, confluent human endometrial epithelial cells (ECC-1 cell line) were wounded and treated with carrier protein (control, 0.1% BSA), activin A (50ng/mL) or EGF (positive control: 50ng/mL). Wound areas were quantitated daily for 6 days. For the in vivo study, serum follistatin levels were measured by ELISA in follistatin overexpressing mice (FS) (2) and wild-type (WT) littermates. Mice were induced to undergo endometrial breakdown and repair (mimicking menstruation in women). Activin βA was immunolocalised during endometrial repair, and extent of repair assessed using our morphological scoring system (2). ECC-1 wound repair was significantly (P &lt; 0.05) enhanced by activin A treatment v. control from days 2–6 of culture. In WT mice, activin βA localised to areas of endometrial repair. Serum follistatin was significantly elevated in FS mice v. controls (33.3 ± 3.8 v 7.07 ± 1.8 ng/mL, P &lt; 0.01). In FS mice (n = 8) only 50% of uterine sections showed complete repair after endometrial breakdown, significantly less than those from WT animals (n = 15, P &lt; 0.05) where 85% of sections demonstrated complete repair. These results demonstrate for the first time that activin A functions to promote endometrial restoration following menses and that this can be delayed under physiological conditions: such studies indicate potential treatments for AUB. (1) Wankell et al. (2001) EMBO J 20:5361–5372 (2) Kaitu'u-Lino et al. (2007) Endocrinology 148:5105–5111

Follistatin serum concentrations during full-term labour in women – significant differences between spontaneous and induced labour

Follistatin has been isolated from human placenta and has been identified in human foetal membranes and fluids. Serum follistatin levels in women rise during pregnancy particularly near term. In this study, we examined the effect of induction and stage of labour on maternal plasma concentrations of follistatin. Women who gave birth after a normal pregnancy were retrospectively divided into three groups: those who went in labour spontaneously (n = 33), needed induction by amniotomy and IV oxytocin (n = 18) or underwent planned caesarean section (n = 10). Serum was collected at 38-40 weeks of gestation, periodically through labour with a vaginal examination and once within 36 h postpartum and assayed for oestradiol, progesterone, prolactin and C-reactive protein. Follistatin was measured using a rabbit antiserum (#204) raised against purified 35 kDa bovine follistatin. Human recombinant follistatin was used as both standard and tracer. Concentrations of follistatin at 38-40 weeks of gestation were significantly different between groups. Those who had a spontaneous labour had concentrations higher than those who were induced. Similarly, those who were induced had concentrations higher than those who underwent a caesarean. In the spontaneous group, follistatin rose during labour, peaking at 57.9 +/- 5.48 ng/ml at > 3 cm of cervical dilation, and after delivery follistatin decreased to 26.16 +/- 3.4 ng/ml at 24 h post-delivery. In induced patients follistatin continued increasing to peak following delivery at 26.9 +/- 3.0 ng/ml and decreased at > 3 h post-delivery. Follistatin concentrations in caesarean section patients at 24 h post-surgery (18.53 +/- 3.74 ng/ml) were not different from that before the surgery and were comparable with the other two groups. Follistatin is clearly implicated in the onset of labour; however, further studies with a larger cohort of women are necessary to determine the nature of its role.