Serum GDF15 Research Articles

Serum Hepcidin and GDF-15 levels as prognostic markers in urothelial carcinoma of the upper urinary tract and renal cell carcinoma

BackgroundCancer is a life-threatening disease that causes every fourth death. It is often hard to determine the time point of progression. Therefore, biomarkers for cancer entities that indicate disease progression or aggressiveness and thereby guide therapeutic decisions are required. Unfortunately, reliable biomarkers are rare. In this study, the potential of serum hepcidin and serum GDF-15 as biomarkers that correlate with patient’s survival in the two entities upper urinary tract urothelial carcinomas (UUTUC) and renal cell carcinoma (RCC) were analyzed.MethodsIn this retrospective study n = 38 patients suffering from UUTUC, n = 94 patients suffering from RCC and n = 21 patients without infections or cancer, all hospitalized at the University Hospital Muenster, were included. Serum samples of patients were retrospectively analyzed. Serum hepcidin and GDF-15 levels were measured and correlated to aggressiveness and progression of the disease as well as patient’s outcome.ResultsFor both entities, UUTUC and RCC, serum hepcidin levels as well as serum GDF-15 levels were increased compared to sera of controls. High serum hepcidin and GDF-15 levels were associated with metastases and cancer relapse. Also, in both entities, the overall survival was decreased in patients with increased serum hepcidin and GDF-15 levels. Hence, high serum hepcidin and GDF-15 levels correlated with patient’s outcome.ConclusionTo conclude, the data of this study show a correlation of high serum hepcidin and GDF-15 levels with aggressiveness and progression of the disease and demonstrate potential prognostic properties of serum hepcidin and GDF-15 levels. The data support the further assessment of serum hepcidin and GDF-15 as prognostic markers in RCC and UUTUC.

Communication of Placental Iron Trafficking Proteins with Maternal and Fetal Iron Regulators

During pregnancy, iron is a primary requisite micronutrient for the developing fetal-placental unit and increased maternal erythrocyte mass expansion. Iron deficiency anemia in pregnancy (IDAP) remains a constant public health problem in our country where all of them receive routine iron supplementation.The mechanism involved in iron regulatory pathway across the placenta is more complex and less understood. Here we examined the hematological and biochemical parameters of mother and fetus, placental mRNA and protein expression of iron trafficking proteins in iron replete and deplete pregnant women.Subjects who presented to the department of community health for child birth were screened and consenting patients (age<35 years and a gestational age≥36weeks) were included in the study. Maternal and cord blood samples were collected and a cut placental tissue (~0.5cm) was obtained at the time of delivery. Hematological and biochemical parameters were analysed according to standard methods. Serum ferritin was measured using chemiluminescent immunoassay. Maternal and cord blood serum hepcidin and GDF15 levels were measured using ELISA (DRG Diagnostics and Ray Biotech, respectively). Placental tissue RNA extracted using PARIS kit (Ambion) and cDNA was synthesised using RT2 first strand Kit (QIAGEN). The relative quantification of twenty two genes involved in iron uptake, export, transport and regulation was done using Custom RT2 PCR Array (SA Biosciences, QIAGEN). Western blot analysis was performed for significantly expressed genes. Statistical analysis was performed using SPSS software.A total of one hundred and thirty eight pregnant women (n=138) were included in the study; 14 subjects were excluded due to unavailability of either maternal or cord blood serum samples. A cut off of ferritin<30ng/mL was taken to define iron deficiency since all of them were on regular iron supplementation during pregnancy. Of the 124 subjects, 28 subjects had iron deficiency anaemia (Hb<10.5g/dL and Ferritin<30ng/mL) and 52 were iron replete (Hb>10.5g/dL and Ferritin>30ng/mL). Forty four women who did not fulfil either of the criteria were not included for analysis. The demographic, hematological and biochemical parameters of the groups are tabulated (Table.1).In the IDAP, even though the maternal serum ferritin levels were reduced, their fetal ferritin levels did not differ significantly from the control fetuses [IDAP fetuses- 139.8ng/mL, 15.4-300.5 vs Control fetuses - 143.4ng/mL, 13.1-461; p= 0.72]. No significant association was observed between ferritin and hepcidin levels either in the maternal or fetal serum. Interestingly, we found a negative correlation between maternal serum GD15 levels and fetal hepcidin: ferritin ratio (r=-0.439; p=0.025). Placental gene expression and protein expression was further analyzed (Table.2). Significantly higher gene expression of placental IREB2 [p=0.011], and ferroportin [p=0.000] were observed in iron deficient cohort. TP53 and LRP1 mRNA expressions were significantly lower in IDAP [p=0.002 & p=0.000]. Maternal serum ferritin had a significant positive correlation with placental expression of IREB2 (r=0.519; p=0.027) and LRP1 (r=0.470; p=0.049). At the protein level, placental GDF15 protein was significantly elevated in IDAP [p=0.04]. Placental GDF15 and ferroportin (FPN) was positively correlated with fetal ferritin (r=0.626; p=0.017 & r=0.552; p=0.041).Even when the maternal iron stores are low, the fetus gets the priority according to the hierarchy of iron usage. In IDAP, we observed a higher expression of placental ferroportin and transferrin receptor which probably leads to the increased efflux of iron towards fetus. Elevated placental GDF15 and ferroportin may imply that they play a major role in accomplishing iron trafficking and has to be further explored. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Dyserythropoiesis Evaluated by Red Score and Hepcidin/Ferritin Levels Predicts Response to Erythropoietin in Lower Risk Myelodysplastic Syndromes

INTRODUCTION: Erythropoiesis stimulating agents (ESA) are generally the first line of treatment of anaemia in lower risk myelodysplastic syndrome (MDS) patients. We prospectively investigated the predictive value of somatic mutations, and biomarkers of ineffective erythropoiesis including flow cytometry RED score, serum GDF-15, and hepcidin levels. METHODS: Inclusion criteria were: ESA naive, IPSS low or intermediate-1 MDS with Hemoglobin (Hb) level< 10g/dL. Patients received epoetin zeta 40 000 IU/week and erythroid response (HI-E, IWG 2006 criteria) was assessed at W12. sEPO level, iron parameters and hepcidin, flow cytometry (FC) Ogata and Red Score (RS), GDF-15, and molecular analysis by NGS were determined at baseline. RESULTS: 70 patients were included. Median age was 78 years. There were 22 RCMD, 19 RCUD, 14 RARS, 4 RAEB-1, 6 CMML, 2 del 5q-, 3 unclassifiable, R-IPSS was 13 very low, 47 low, 9 intermediate and high. Twenty patients were transfusion-dependent. HI-E was 48% and median duration of response was 26 months. At baseline, non-responders had significantly higher FC Red Score, lower hepcidin/ferritin ratio, lower IPSS. In multivariate analysis, only RS>4 at T0 (p=0.05) and hepcidin/ferritin 2000 pg/ml and hepcidin/ferritin<9 (P=0.0008, and p=0.01, respectively). In multivariate analysis, both variables were associated with a shorter duration of response. CONCLUSION: Erythroid response to epoetin zeta was similar to that obtained with other ESAs. It was correlated with higher baseline hepcidin/ferritin ratio and lower Red score. Clinical Trial Number: Clinical trial Gov as NCT03598582. Funding Statement: This study received the support of a research grant from Hospira/Pfizer, the institutional support of Assistance Publique-Hopitaux de Paris through the Unite de Recherche Clinique Paris Descartes Necker Cochin. Declaration of Interests: Sophie Park has received research funding from Hospira/Pfizer. The remaining authors declare no competing financial interests. Ethic Approval Statement: All patients gave their written informed consent for biological investigations according to the recommendations of the local ethics committee (Comite de Protection des Personnes Paris V, CPP N° RCB 212-A01395-38, EUDRACT 2012-002990-7338) and the study was conducted in accordance with the Helsinki Declaration.

GDF15 predict platinum response during first-line chemotherapy and can act as a complementary diagnostic serum biomarker with CA125 in epithelial ovarian cancer

BackgroundGrowth differentiation factor 15 (GDF15) has attracted much interest as a novel biomarker for epithelial ovarian carcinoma (EOC). Research focus has been directed at GDF15 as a diagnostic detection, while the prognostic determination of GDF15 in EOC patients remains to be clearly elucidated. The present study aimed to investigate GDF15 level relative to clinicopathological characters, chemoresponse, and clinical outcome of EOC patients.MethodsSerum from 122 patients with primary diagnosed EOC were analyzed for GDF15 and serum cancer antigen 125 (CA125). All cases were treated with debulking surgery and first-line chemotherapy, and samples were obtained just before debulking surgical treatment and first-line chemotherapy. Subsequently, clinical characteristics, responses to chemotherapy and progression-free survival (PFS) were recorded.ResultsIncreasing levels of serum GDF15 was significantly associated with FIGO stage and lymphonodus metastasis. GDF15 and CA125 detection are complementary in the diagnosis of EOC and can be simultaneously profiled. The chemo-resistant EOC patients (median, 1225.0 pg/mL) showed significantly higher GDF15 than chemo-sensitive patients (median, 824.2 pg/mL; P = 0.013). Highly expressed GDF15 was an independent negative prognostic indicator in the PFS (P = 0.026) of the 122 EOC cases in the multivariate analysis. Additionally, patients with high level of serum CA125 significantly associated with suboptimal (P = 0.043) debulking surgery.ConclusionsOur results provide valuable evidence that GDF15 is related with first-line chemo-resistance, with highly expressed GDF15 being a strong and an independent indicator of shorter PFS in EOC patients.

Growth differentiation factor 15 as a predictor of adverse renal outcomes in patients with immunoglobulin A nephropathy.

Growth differentiation factor 15 (GDF 15) has recently been reported as a useful prognostic marker in patients with chronic inflammatory disease and heart disease. To evaluate the role of GDF 15 as a potential prognostic predictor of renal outcome in immunoglobulin A nephropathy (IgAN). In total, 212 patients in the Chungnam National Hospital glomerulonephritis cohort, who were diagnosed as biopsy-proven IgAN between March 2010 and June 2014, were included. GDF Fifteen was analysed by the enzyme-linked immunosorbent assay. Cut-off values of the GDF 15 and the hazard ratio of it resulting in haemodialysis within 2 years were analysed. The level of serum GDF 15 was negatively correlated with the initial eGFR. A serum GDF 15 level of more than 496.32 pg/mL showed 90% sensitivity and 72.9% specificity to predict the possibility of it resulting in haemodialysis within 2 years. In addition, a GDF 15 level higher than 490.4 pg/mL showed 63.64% sensitivity and 65% specificity to predict a decline in eGFR > 30 mL/min within 1 year of follow up. Moreover, initial serum GDF 15 level was associated with the development of interstitial fibrosis/tubular atrophy. Initial serum GDF 15 level showed an inverse correlation with serum eGFR and was associated with worse renal outcome. Our results suggested that GDF 15 may play a role as a potential prognosticator in IgAN.

Plasma GDF15 level is elevated in psychosis and inversely correlated with severity

Accumulating evidence suggests that GDF15 is a biomarker for ageing and morbidity of many somatic disorders such as cancer and inflammatory disorders. Recently, elevated serum GDF15 level was proposed as a marker for mood disorder. However, psychosis severity was not investigated in relation to plasma GDF15 levels. In the present study we measured GDF15 levels in plasma of 120 psychosis patients compared to 120 age and gender matched healthy controls. Within the patient cohort GDF15 levels were evaluated for association with age, gender, lifestyle factors, C-reactive protein levels, psychosis severity and metabolic disorder. Psychosis patients had elevated GDF15 levels compared to controls (medianPsychosis = 744 ng/mL, mediancontrols = 516 ng/mL, p < 0.001). Within the psychosis cohort, GDF15 levels, when corrected for age, metabolic health and lifestyle factors, were negatively correlated with psychosis severity (β = −0.218, p = 0.012). While GDF15 levels were elevated in patients versus healthy controls, the negative correlation between psychosis severity and GDF15 suggests a loss of anti-inflammatory GDF15 mediated functionality in severe psychosis. Study replication in larger cohorts will be necessary to assess the potential of GDF15 as a prognostic biomarker in psychosis.

Serum Concentration of Growth Differentiation Factor-15 Is Independently Associated with Global Platelet Function and Higher Fibrinogen Values in Adult Healthy Subjects.

AbstractGrowth differentiation factor-15 (GDF-15) has recently emerged as a strong and independent predictor of cardiovascular events and mortality. However, the pathophysiological mechanisms underlying this important association remain speculative. This study was aimed to investigate the potential associations between the serum concentration of GDF-15 and clinical or laboratory parameters in a population of ostensibly healthy subjects. The study population consisted of 44 healthy volunteers enrolled from the laboratory staff (14 males and 30 females; mean age, 47 ± 11 years), who had their blood collected for assessing complete blood cell count, GDF-15, serum creatinine, albumin, cardiac troponin T, galectin-3, routine coagulation tests, D-dimer, von Willebrand factor, and platelet function testing using platelet function analyzer-100. In univariate analysis, serum GDF-15 was found to be positively associated with age and plasma fibrinogen, and negatively associated with renal function and collagen-epinephrine (CEPI). In multiple linear regression analysis, serum GDF-15 remained significantly associated with renal function, CEPI, and plasma fibrinogen. Healthy subjects with GDF-15 above the median value had a twofold probability of displaying shorter CEPI closure times. Taken together, these results suggest that higher serum values of GDF-15 may be associated with overall global platelet hyperactivity and increased plasma fibrinogen, so providing another plausible explanation for the association between GDF-15, cardiovascular events, and mortality.

Mitochonic Acid 5 (MA-5) Facilitates ATP Synthase Oligomerization and Cell Survival in Various Mitochondrial Diseases

Mitochondrial dysfunction increases oxidative stress and depletes ATP in a variety of disorders. Several antioxidant therapies and drugs affecting mitochondrial biogenesis are undergoing investigation, although not all of them have demonstrated favorable effects in the clinic. We recently reported a therapeutic mitochondrial drug mitochonic acid MA-5 (Tohoku J. Exp. Med., 2015). MA-5 increased ATP, rescued mitochondrial disease fibroblasts and prolonged the life span of the disease model “Mitomouse” (JASN, 2016). To investigate the potential of MA-5 on various mitochondrial diseases, we collected 25 cases of fibroblasts from various genetic mutations and cell protective effect of MA-5 and the ATP producing mechanism was examined. 24 out of the 25 patient fibroblasts (96%) were responded to MA-5. Under oxidative stress condition, the GDF-15 was increased and this increase was significantly abrogated by MA-5. The serum GDF-15 elevated in Mitomouse was likewise reduced by MA-5. MA-5 facilitates mitochondrial ATP production and reduces ROS independent of ETC by facilitating ATP synthase oligomerization and supercomplex formation with mitofilin/Mic60. MA-5 reduced mitochondria fragmentation, restores crista shape and dynamics. MA-5 has potential as a drug for the treatment of various mitochondrial diseases. The diagnostic use of GDF-15 will be also useful in a forthcoming MA-5 clinical trial.

FGF21 is a biomarker for mitochondrial translation and mtDNA maintenance disorders.

To validate new mitochondrial myopathy serum biomarkers for diagnostic use. We analyzed serum FGF21 (S-FGF21) and GDF15 from patients with (1) mitochondrial diseases and (2) nonmitochondrial disorders partially overlapping with mitochondrial disorder phenotypes. We (3) did a meta-analysis of S-FGF21 in mitochondrial disease and (4) analyzed S-Fgf21 and skeletal muscle Fgf21 expression in 6 mouse models with different muscle-manifesting mitochondrial dysfunctions. We report that S-FGF21 consistently increases in primary mitochondrial myopathy, especially in patients with mitochondrial translation defects or mitochondrial DNA (mtDNA) deletions (675 and 347 pg/mL, respectively; controls: 66 pg/mL, p < 0.0001 for both). This is corroborated in mice (mtDNA deletions 1,163 vs 379 pg/mL, p < 0.0001). However, patients and mice with structural respiratory chain subunit or assembly factor defects showed low induction (human 335 pg/mL, p < 0.05; mice 335 pg/mL, not significant). Overall specificities of FGF21 and GDF15 to find patients with mitochondrial myopathy were 89.3% vs 86.4%, and sensitivities 67.3% and 76.0%, respectively. However, GDF15 was increased also in a wide range of nonmitochondrial conditions. S-FGF21 is a specific biomarker for muscle-manifesting defects of mitochondrial translation, including mitochondrial transfer-RNA mutations and primary and secondary mtDNA deletions, the most common causes of mitochondrial disease. However, normal S-FGF21 does not exclude structural respiratory chain complex or assembly factor defects, important to acknowledge in diagnostics. This study provides Class III evidence that elevated S-FGF21 accurately distinguishes patients with mitochondrial myopathies from patients with other conditions, and FGF21 and GDF15 mitochondrial myopathy from other myopathies.

Growth differentiation factor 15 increases following oral glucose ingestion: effect of meal composition and obesity.

Growth differentiation factor 15 (GDF15) is a cardiovascular biomarker belonging to the transforming growth factor-β superfamily. Increased GDF15 concentrations are associated with insulin resistance, diabetes and obesity. We investigated the physiological effects of meal composition and obesity on the regulation of systemic GDF15 levels. Lean (n = 8) and obese (n = 8) individuals received a carbohydrate- or fat-rich meal, a 75 g oral glucose load (OGTT) or short-term fasting. OGTTs were performed in severely obese patients (n = 6) pre- and post-bariatric surgery. Circulating serum GDF15 concentrations were studied in lean and obese individuals in response to different meals, OGTT or short-term fasting, and in severely obese patients pre- and post-bariatric surgery. Regulation of GDF15 mRNA levels and protein release were evaluated in the human hepatic cell line HepG2. GDF15 concentrations steadily decrease during short-term fasting in lean and obese individuals. Carbohydrate- and fat-rich meals do not influence GDF15, whereas an OGTT leads to a late increase in GDF15 levels. The positive effect of OGTT on GDF15 levels is also preserved in severely obese patients, pre- and post-bariatric surgery. We further studied the regulation of GDF15 mRNA levels and protein release in HepG2, finding that glucose and insulin independently stimulate both GDF15 transcription and secretion. In summary, high glucose and insulin peaks upregulate GDF15 transcription and release. The nutrient-induced increase in GDF15 levels depends on rapid glucose and insulin excursions following fast-digesting carbohydrates, but not on the amount of calories taken in.

Effects of exercise program on normal responsiveness of serum GDF15 in middle-aged women

Effects of exercise program on normal responsiveness of serum GDF15 in middle-aged women

Can Serum Gdf-15 be Associated with Functional Iron Deficiency in Hemodialysis Patients?

Functional iron deficiency (FID) incidence is gradually increasing in hemodialysis (HD) patients. Recently, high levels of GDF-15 supressed the iron regulatory protein hepcidin and GDF-15 expression increased in iron-deficient patients. The relationship between FID, GDF-15, and hepcidin is currently unknown. The present study aimed to evaluate the association between GDF-15, hepcidin, and FID in chronic HD patients. Serum GDF-15 and hepcidin concentrations were measured in 105 HD patients and 40 controls. FID is defined as serum ferritin >800ng/mL, TSAT <25%, Hb levels <11g/dL, and reticulocyte haemoglobin content (CHr) <29pg. Serum GDF-15 and hepcidin levels were increased significantly in HD patients with FID, compared to HD patients without anemia and controls. GDF-15 correlated with ferritin, hepcidin, and CRP in the entire cohort. GDF-15 was related to ferritin and CRP in HD patients with FID. GDF-15 is better diagnostic marker than hepcidin for detection of FID [AUC=0.982 (0.013) versus AUC=0.921 (0.027); P=0.0324]. GDF-15 appears to be a promising tool for detection of FID. High levels of ferritin and CRP correlated with GDF-15. Our results support GDF-15 as a new mediator of FID via hepcidin, chronic inflammation, or unknown pathways.

GDF15 Promotes Osteoclast Differentiation and High Serum GDF15 Levels Are Associated with Multiple Myeloma Bone Disease

IntroductionGrowth differentiation factor 15 (GDF15) is a multifunctional growth factor of the transforming growth factor beta (TGFbeta) family that plays a complex role in several types of cancers. In multiple myeloma, GDF15 was recently shown to enhance the tumor-initiating and self-renewal potential of the cancer cells (Tanno et al, Blood 2014). Moreover, blood and bone marrow plasma levels of GDF15 are elevated in myeloma patients compared with healthy persons, and high serum levels are associated with a poor prognosis (Corre et al, Cancer Research 2012). GDF15 seems important for bone remodeling during hypoxia (Hino et al, JBMR 2012), and one study proposed GDF15 to increase osteoclast activation in prostate cancer metastasizing to bone (Wakchoure et al, Prostate 2009). Whether GDF15 plays a role in the bone disease of multiple myeloma is not well characterized.AimOur aim was to investigate whether high GDF15 serum levels are associated with multiple myeloma bone disease and to characterize the effect of GDF15 on osteoclast differentiation in vitro.MethodsGDF15 was measured in serum samples obtained at diagnosis from 138 myeloma patients and 58 age and sex-matched healthy controls. The patient serum samples were collected for the Nordic Myeloma Study Group during a randomized phase 3 clinical trial which compared the effect of two different doses of pamidronate on bone. The bone disease was therefore particularly well-characterized in this study (Gimsing et al, Lancet Oncol 2010). Peripheral blood mononuclear cells (PBMC) isolated from buffy coats were cultured in osteoclast medium (a-MEM with human serum (20%), M-CSF (30ng/ml) and RANKL (50ng/ml)) for up to 14 days with or without GDF15. Purchased pre-osteoclasts (Lonza Inc.) were cultured in purchased bullet kit (OC medium with M-CSF (33ng/ml) and RANKL (66ng/ml)) for 7 days with or without GDF15. Cells positive for tartrate resistant acidic phosphatase (TRAP) staining and with more than two nuclei were counted as osteoclasts.ResultsGDF15 was significantly higher in serum obtained from myeloma patients (median 1.08 ng/ml, range 27.91) compared with healthy controls (median 0.46 ng/ml, range 1.66, Independent samples Kruskal-Wallis test p< 0.0001). Moreover, serum GDF15 was elevated in patients with a more advanced osteolytic bone disease (n= 51, median 1.44 ng/ml, range 6.48) as compared to patients without osteolytic lesions (n= 16, median 0.84 ng/ml, range 10.62) at inclusion (p<0.05). The difference between serum GDF15 in patients with limited bone disease at inclusion (n=51, median 1.07 ng/ml, range 6.84) and patients with no bone disease at baseline was not significantly different.In vitro, addition of GDF15 (0-100 ng/ml) to osteoclast precursors or PBMC increased numbers of multi-nucleated TRAP positive cells in a dose dependent manner (n=3, O ng/ml GDF15 mean 25.7, SEM 5.9, 2 ng/ml GDF15 mean 29.7, SEM 4.3, 20 ng/ml GDF15 mean 38.7, SEM 4.9, 50 ng/ml GDF15 mean 53.3, SEM 11.6, 100 ng/ml GDF15 mean 78.7 SEM 7.8). OPG inhibited the pro-osteoclastogenic activity of GDF15 inferring that the effect is mediated by RANKL. Hence, GDF15 increases osteoclast differentiation.ConclusionSerum GDF15 is elevated in myeloma patients with advanced osteolytic bone disease compared to patients with no lesions. GDF15 increases osteoclast differentiation in vitro. Hence, GDF15 could play a role in regulating bone remodeling in myeloma patients. DisclosuresNo relevant conflicts of interest to declare.

Abstract 133: Prognostic Utility of the GDF-15/FSTL-1 Axis for Adverse Cardiac and Limb Events in Patients With Peripheral Artery Disease

Background: Peripheral artery disease (PAD) confers greater vulnerability to cardiovascular events. Inflammatory activation and tissue ischemia induce expression of a vasoprotective cytokine network including GDF15 and FSTL1. We sought to evaluate the clinical utility of novel vascular stress biomarkers for risk stratification in PAD. Methods and Results: We followed 245 PAD patients prospectively over two years for adverse cardiac events (n=40, myocardial infarction, unstable angina, coronary revascularization, transient ischemic event, stroke, congestive heart failure, cardiac death) and adverse limb events (n=52, worsening claudication, peripheral revascularization, critical limb ischemia, amputation, graft or stent failure). At baseline, we measured serum GDF15 and FSTL-1 and disease severity by the ankle-brachial index (ABI). In survival analyses, higher GDF15 was associated with both adverse cardiac and limb events (P&lt;0.0001, P&lt;0.01). FSTL-1 was associated with adverse limb (P=0.03) but not cardiac events. In multivariable models adjusting for relevant covariates including ABI, higher GDF15 remained associated with higher risk of limb events (HR 1.83, 95% CI 1.10, 3.06, P=0.02) and cardiac events (HR 1.92, 95% CI 1.09, 3.32, P=0.02). There was a trend for an association of higher FSTL1 with limb events (HR 2.34, 95% CI 0.93, 5.75, P=0.07). Addition of GDF15 to clinical variables led to an increase in the c statistic (P&lt;0.05) and net reclassification improvement (P&lt;0.01) for both cardiac and limb events. Conclusions: Our findings show that vascular stress markers involving the GDF15-FSTL1 axis provide additional prognostic value over clinical factors and disease severity for predicting adverse cardiac and limb events in patients with PAD.

Serum Growth Differentiation Factor 15 Levels in Newly Diagnosed Multiple Myeloma Patients

Background/Aims: Multiple myeloma (MM) is a hematological cancer associated with increased clonal malignant plasma cells. Growth differentiation factor 15 (GDF 15) is a protein that is highly expressed in the bone marrow mesenchymal stem cells of patients with MM. This study investigated whether the clinical stage of the disease, treatment response and survival are affected by pretreatment serum GDF 15 levels. Methods: Serum GDF 15 levels were measured in 35 newly diagnosed MM patients and 27 healthy controls. The correlation between serum GDF 15 levels and various clinical and laboratory parameters was analyzed. Results: The study demonstrated significantly higher levels of GDF 15 in MM patients. There was a negative correlation between GDF 15 levels, hemoglobin and albumin levels, and a positive correlation between GDF 15 levels, CRP, creatinine, β-2-microglobulin and stage. GDF 15 levels were lower in patients who could receive autologous stem cell transplantation compared to other groups, representing a statistically significant difference. However, in the survival analyses, GDF 15 level did not have an impact on survival. Conclusion: High serum levels of GDF 15 may indicate a poor treatment response. Our study supports the prognostic value of GDF 15 in MM.

Multiplexed VeraCode bead-based serological immunoassay for colorectal cancer

Colorectal cancer (CRC) is the second leading cause of cancer deaths in the US and Western world. Despite increased screening and advances in treatment, the mortality rate (ca. 50,000/year) and high national health-care burden for CRC are likely to remain high unless an effective non-invasive screening test for CRC is instituted for a large segment of the population. Blood-based protein biomarkers hold great promise for early disease diagnosis and personalized medicine; yet robust and reproducible multiplexing platforms and methodologies have lagged behind their genomic counterparts.Here, we report the development of a novel, multiplexed, hybrid immunoassay for CRC that is formatted on barcoded VeraCode™ micro-beads, which have until now only been used for genomic assays. The method combines a sandwich immunoassay format for detection of serum protein biomarkers with an antigen assay for autoantibody detection. The serum protein biomarkers CEA and GDF15 as well as autoantibodies to the p53 tumor associated antigen (TAA) were used to exemplify the method. This multiplex biomarker panel was configured to run on Illumina's holographically barcoded VeraCode™ micro-bead platform, which is capable of measuring hundreds of analytes simultaneously in a single well from small volumes of blood (<50μL) using a 96-well industry standard microtiter plate. This novel use of the VeraCode™ micro-bead platform translates into a potentially low volume, high throughput, multiplexed assay for CRC, for the purposes of biomarker validation, as well as patient screening, diagnostics and prognostics. In an evaluation of a 186 patient sera training set (CRC and normal), we obtained a diagnostic sensitivity of 54% and a specificity of 98%. We anticipate that by expanding and refining the biomarkers in this initial panel, and performing more extensive clinical validations, such an assay could ultimately provide a basis for CRC population screening to complement the more invasive, expensive and low throughput (but highly sensitive and specific) colonoscopy.

Serum hepcidin and growth differentiation factor‐15 (GDF‐15) levels in polycythemia vera and essential thrombocythemia

Hepcidin plays a regulatory role in systemic iron homeostasis. GDF-15 has been found to be expressed from matured erythroblasts and very high levels of GDF-15 suppresses hepcidin secretion. In this study, we evaluated hepcidin and GDF-15 levels in polycythemia vera (PV) and essential thrombocythemia (ET). The study included 29 patients and 21 healthy controls. The patient group included 13 patients with ET and 16 patients with PV. Serum hepcidin and GDF-15 levels were measured at the time of diagnosis, before the initiation of any therapy. Hepcidin levels did not differ significantly in patients with chronic myeloproliferative disease (CMPD) and healthy controls. However, GDF-15 levels were significantly increased in patients with CMPD (P=0.038). No difference could be found between patients with PV and ET in terms of hepcidin and GDF-15 levels. Patients with JAK2-V617F mutation had increased GDF-15 levels when compared with patients without this mutation (P: 0.006). The levels of GDF-15 were higher in CMPD, which are characterized by increased erythropoiesis, and this effect was more pronounced particularly in individuals with JAK2-V617F mutation. Hepcidin levels were not suppressed despite the increased erythroid activity and GDF-15 levels may be protective against the clinical complications of the disease such as thrombosis. This study revealed that, hepcidin levels were not suppressed despite increased erythroid activity and high GDF-15 levels in CMPD. We hypothesized that, this may be an attempt to prevent further amplification of erythropoietic activity by reducing iron utilization.

Measurement of serum growth differentiation factor 15 concentration in children with hemophagocytic lympohistiocytosis and implications in the development of hyperferritinemia

Objective To measure the serum growth differentiation factor (GDF15) levels in children with hemophagocytic lympohistiocytosis (HLH), and to explore its possible implications in the development of hyperferritinemia in HLH. Methods Twenty-eight children with newly-diagnosed HLH and 20 age-and-sex matched healthy children were enrolled in this study as research subjects and controls respectively.Serum GDF15 levels were measured by Quantikine ELISA assay (product of R&D Company, USA) according to manufacturer's instructions.Serum ferritin concentration and other biochemical parameters were determined by conventional methods.Comparison of serum GDF15 levels between HLH group and healthy control group were made by nonparametric Mann-Whitney test.Correlations between serum GDF15 concentration and hemobiochemical parameters (Hb, serum ferritin, fibrinogen, blood lipids, and liver and renal function tests) were made via Spearman correlation analysis. Results Serum GDF15 concentration was significantly higher in HLH group than that in healthy control group, with median concentrations and ranges of 1710 ng/L, 190-2400 ng/L, and 260 ng/L, 104-649 ng/L, respectively (P<0.001). Serum GDF15 concentration was correlated neither to Hb concentration at diagnosis nor to lowest Hb concentration before HLH-directed chemotherapy.Nevertheless it was positively correlated to serum level of total bilirubin at diagnosis and highest concentration of trigly-cerates during disease course(χ2=0.475, 0.465; P=0.011, 0.019, respectively), and negatively correlated to lowest levels of fibrinogen and albumin at diagnosis (χ2=-0.423, -0.399; P=0.031, 0.039, respectively). Serum GDF15 level was not correlated to underlying etiology and mortality rate of children with HLH. Conclusions GDF15 has been documented as an upstream negative regulator of hepcidin, the central iron regulatory hormone produced primarily by hepatocytes, and is massively produced by activated macrophages in an autocrine fashion to suppress further activation of macrophages.This research finding that serum GDF15 level is significantly elevated in children with HLH suggests that GDF 15 is intimately implicated in the modulation of iron homeostasis and the development of hyperferritinemia in HLH. Key words: Hemophagocytic lympohistiocytosis; Growth differentiation factor 15; Hyperferritinemia; Child

SERUM EXPRESSION LEVELS OF GDF-15 IN PATIENTS WITH CAD

Objectives1. To determine the serum expression levels of GDF-15 in peripheral blood among Group STEMI, NSTEMI, UA, CAD, non-CAD by ELISA.2. To investigate the relationships between GDF-15 and severity/characteristics of...

GDF 15 as an anti-apoptotic, diagnostic and prognostic marker in oral squamous cell carcinoma

Growth-differentiation factor 15 (GDF 15) is involved in tumor pathogenesis and its expression is increased in many types of cancers. Functional effects of GDF 15 on oncogenesis of oral squamous cell carcinoma (OSCC) remain unclear. Therefore, the aim of this study was to examine the apoptotic characteristics of GDF 15 in OSCC cell lines in vitro and to analyze serum GDF 15 concentrations as a diagnostic and prognostic tumor marker for OSCC in vivo. Caspase activity was assessed in OSCC cell lines with the Caspase-Glo 3/7 system. Serum GDF 15 concentrations from 64 patients with histopathological proven OSCC and from 30 healthy volunteers were measured using an enzyme-linked immunosorbent assay. In 21 patients, serum GDF 15 was also analyzed postoperatively. In vitro, treatment of OSCC cell lines with GDF 15 reduced Caspase 3/7 activity significantly (p<0.05). In vivo, serum GDF 15 concentrations of the OSCC patients in all stages of OSCC were significantly higher than those of the healthy subjects (p<0.0001). After surgery, GDF 15 concentrations declined significantly from 1545±774pg/ml preoperative to 953±438pg/ml postoperative (p=0.003). The median survival time of OSCC patients with GDF 15 levels below 875pg/ml was significantly higher than of OSCC patients with GDF 15 levels above or equal 875pg/ml (p=0.031). Determination of receiver operating characteristic curves (ROC) showed a respective area under the ROC curve (AUC) of 0.943. The anti-apoptotic effect of GDF 15 in OSCC cell lines was shown in vitro. In vivo, significant elevated serum GDF 15 levels with prognostic value in OSCC-patients were seen for the first time. The results indicate that GDF15 may be used as a potential marker for diagnosis and prognosis of this entity.