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BACKGROUND AND OBJECTIVES: Systemic sclerosis (SSc) is an autoinmune disease that can affect several organs and its mortality is fundamentally related to its pulmonary involvement. There are some cytokines with high serum levels of patients with SSc. Our goal is to determine the role of CXCL4, CXCL8 and GDF15 in the physiopathology of SSc and whether they can be considered organic damage biomarkers. PATIENTS AND METHODS: Observational case-control study of SSc patients (ACR/EULAR 2013 criteria). Demographic, clinical, analytical, activity, severity, health perception, and disability variables were collected. Moreover, Videocapillaroscopy, Echocardiography and Respiratory Function Test were made. Serum levels of CXCL4, CXCL8 and GDF15 were measured both in SSc patients and in healthy controls. RESULTS: A total of 42 patients were included (95.4% women), with an average age of 59.2 years and a median of 4 years from diagnosis. We also included 42 healthy controls. We found significantly higher levels of GDF15 in SSc patients than in controls (p

Growth differentiation factor 15 or macrophage inhibitory cytokine-1 (GDF15/MIC-1) is a divergent member of the transforming growth factor β superfamily and has a diverse pathophysiological role in cancers, cardiometabolic disorder, and other diseases. GDF15 can control hematopoietic growth, energy homeostasis, adipose tissue metabolism, body growth, bone remodeling, and response to stress signals. The role of GDF15 in cancer development and progression is complicated and depends on the specific cancer type, stage, and tumor microenvironment. Recently, research on GDF15 and GDF15-associated signaling has accelerated due to the identification of the GDF15 receptor: glial cell line-derived neurotrophic factor (GDNF) family receptor α-like (GFRAL). Therapeutic interventions to target GDF15 and/or GFRAL revealed the mechanisms that drive its activity and might improve overall outcomes of patients with metabolic disorders or cancer. The present review highlights the structure and functions of GDF15 and its receptor, emphasizing the pleiotropic role of GDF15 in obesity, tumorigenesis, metastasis, immunomodulation, and cachexia.

Aging is one of the primary factors influencing development of osteoarthritis, and the TGF-β pathway plays an important role in age-related osteoarthritis. Specifically, GDF15 phosphorylates SMAD2/3 in the TGF-β pathway to inhibit cardiomyocyte hypertrophy, and promote proliferation of chondrocytes. However, age-dependent changes in the level of GDF15 are unclear, as is whether GDF15 phosphorylates SMAD2/3 in the TGF-β pathway to promote proliferation of old chondrocytes. This study, therefore, sought to examine the effect of various GDF15 concentrations on old chondrocyte proliferation.Serum and cartilage specimens of young adults and older adults were collected, and GDF15 expression was quantified. Human chondrocytes were then cultured following routine protocols, and different concentrations of recombinant human GDF15 or pSMAD2 inhibitor were added into the culture medium. After 48 h of culturing, the proliferation of chondrocytes was detected by EdU, and the expression MMP13, SMAD2, and pSMAD2 was detected in chondrocytes via western blot and qRT-PCR analysis.The GDF15 content in serum and cartilage of young adults was higher than that of older adults (p 0.05). The number of EdU-positive cells in the experimental group (containing recombinant human GDF15) was higher than that in the control group (medium only) (p 0.05). Compared with the control group, chondrocytes in the experimental group showed increased pSMAD2 and type II collagen content (p 0.05) and decreased MMP13 (p 0.05), with no significant difference in SMAD2 content (p 0.05). Moreover, no significant differences were observed between the control group and the TGF-β signaling inhibitor group. The gene expression level of each index was consistent with the protein expression level.The GDF15 content of serum and cartilage in young adults is higher than in older adults, and GDF15 functions to promote the proliferation of chondrocytes by phosphorylating SMAD2 in older individuals.

Background & Aims Patients with acute-on-chronic liver failure (ACLF) present a systemic hyperinflammatory response associated with increased circulating levels of small-molecule metabolites. To investigate whether these alterations reflect inadequate cell energy output, we assessed mitochondrial morphology and central metabolic pathways with emphasis on the tricarboxylic acid (TCA) cycle in peripheral leukocytes from patients with acutely decompensated (AD) cirrhosis, with and without ACLF. Methods The study included samples from patients with AD cirrhosis (108 without and 128 with ACLF) and 41 healthy individuals. Leukocyte mitochondrial ultrastructure was visualized by transmission electron microscopy and cytosolic and mitochondrial metabolic fluxes were determined by assessing NADH/FADH2 production from various substrates. Plasma GDF15 and FGF21 were determined by Luminex and acylcarnitines by LC-MS/MS. Gene expression was analyzed by RNA-sequencing and PCR-based glucose metabolism profiler array. Results Mitochondrial ultrastructure in patients with advanced cirrhosis was distinguished by cristae rarefication and swelling. The number of mitochondria per leukocyte was higher in patients, accompanied by a reduction in their size. Increased FGF21 and C6:0- and C8:0-carnitine predicted mortality whereas GDF15 strongly correlated with a gene set signature related to leukocyte activation. Metabolic flux analyses revealed increased energy production in mononuclear leukocytes from patients with preferential involvement of extra-mitochondrial pathways, supported by upregulated expression of genes encoding enzymes of the glycolytic and pentose phosphate pathways. In patients with ACLF, mitochondrial function analysis uncovered break-points in the TCA cycle at the isocitrate dehydrogenase and succinate dehydrogenase level, which were bridged by anaplerotic reactions involving glutaminolysis and nucleoside metabolism. Conclusions Our findings provide evidence at the cellular, organelle and biochemical levels that severe mitochondrial dysfunction governs immunometabolism in leukocytes from patients with AD cirrhosis and ACLF. Lay summary Patients at advanced stages of liver disease have dismal prognosis due to vital organ failures and the lack of treatment options. In this study, we report that the functioning of mitochondria, which are known as the cell powerhouse, is severely impaired in leukocytes of these patients, probably as a consequence of intense inflammation. Mitochondrial dysfunction is therefore a hallmark of advanced liver disease.

Serum growth differentiation factor 15 (GDF15) is a useful biomarker of mitochondrial diseases; its utility in newborns remains unknown. To investigate the temporal change in GDF15 within the first week of life, and to identify its potential control variables, blood samples were obtained from 18 newborns. The GDF15 levels declined to approximately 35% of the cord blood levels within the first week of life and were negatively correlated with postnatal age and Z-score of birth weight but were positively correlated with N-terminal pro-brain natriuretic peptide and lactate levels. GDF15 levels may reflect the progress of postnatal transition to aerobic metabolism.

Mitochondrial disorders are often difficult to diagnose because of diverse clinical phenotypes. FGF-21 and GDF-15 are metabolic hormones and promising biomarkers for the diagnosis of these disorders. This study has systematically evaluated serum FGF-21 and GDF-15 levels by ELISA in a well-defined cohort of patients with definite mitochondrial disorders (n = 30), neuromuscular disease controls (n = 36) and healthy controls (n = 36) and aimed to ascertain their utility in the diagnosis of mitochondrial disorders. Both serum FGF-21 and GDF-15 were significantly elevated in patients with mitochondrial disorders, especially in those with muscle involvement. The levels were higher in patients with mitochondrial deletions (both single and multiple) and translation disorders compared to respiratory chain subunit or assembly factor defects.

Aim of the work: This study was conducted to assess serum level of growth differentiation factor-15(GDF-15) in Behcet’s disease (BD) patients and its relationship with clinical characteristics, ultrasound findings and disease activity. Patients and methods: Study included 30 BD patients and 20 matched healthy controls. Visual analog scale (VAS)-pain of affected joints and Behcet’s disease current activity form (BDCAF) were assessed. The most affected joints and surrounding soft tissues were assessed by musculoskeletal ultrasound (MSUS).Serum GDF-15 level was measured. Results: Patients were 23 males and 7 females (M:F 3.3:1) with a mean age of 34.6 ± 8.6 years and mean disease duration of 6.6 ± 4.5 years. 18(60%) had arthritis and arthralgia. The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were 26.2 ± 21.2 mm/1sthr and 50.4 ± 37 mg/dl respectively. There was significant increase of GDF-15 levels in patients with articular affection (3492.3 ± 4618.8 ng/ml) compared to those without (338.9 ± 90.3 ng/ml) and controls (322 ± 78.8 ng/ml) (p

Background and aims Patients with peripheral arterial disease (PAD) are at high risk for fatal events. We aimed to investigate the ability among several serum proteins to predict all-cause mortality in outpatients with PAD. Methods Consecutive outpatients with carotid and/or lower extremity PAD were included in the discovery cohort (n = 436), and subjects with PAD from a population-based sample in the validation cohort (n = 129). Blood samples were analyzed for 81 proteins by a proximity extension assay. The proteins best predicting incident all-cause mortality were identified using L1-regularized Cox regression. The added value of the identified proteins to clinical risk markers was evaluated by Cox regression models and presented by the area under the receiver operator characteristics curves (AUC). Results In the discovery cohort (mean age 70 years; 59% men), 195 died (4.8 events per 100 person-years) during a 10.3 years median follow-up. The clinical risk markers generated an AUC of 0.70 (95% confidence interval [95%CI] 0.65–0.76). The two serum protein biomarkers with best prediction of all-cause mortality were growth differentiation factor 15 and tumor necrosis factor-related apoptosis-inducing ligand receptor 2. Adding these proteins to the clinical risk markers significantly improved prediction (p Conclusions In a large-sample targeted proteomics assay, we identified two proteins that improved risk prediction beyond the COPART risk score. The use of high-throughput proteomics assays may identify potential biomarkers for improved risk prediction in patients with PAD.

Background Growth differentiation factor 15 (GDF 15) is a member of the transforming growth factor-beta superfamily and is considered to be a useful biomarker for severity of heart failure (HF) in repaired congenital heart disease (CHD). The aim of this study was to determine the clinical implication of GDF 15 in children with unrepaired CHD. Methods Subjects included 69 patients (≤14 years old) who had unrepaired CHD with left to right shunt and underwent cardiac catheterization. Demographic and hemodynamic data, including oxygen demand–supply relationship, were collected from medical records. Severity of HF was evaluated using modified Ross score. Serum GDF 15 levels were determined using enzyme-linked immunosorbent assay and correlated with patients’ demographics, hemodynamic data, and blood chemistry data. Results Subjects had median age of 71 (range 1–173) months and simple acyanotic CHDs with mean pulmonary to systemic flow ratio of 2.0 (1.0–5.6), median N-terminal pro type Brain natriuretic peptide (NT-pro-BNP) of 162.8 (17.1–8789) pg/mL, and median GDF 15 of 242.1 (13.6–1116.7) pg/mL. GDF 15 significantly positively correlated with the modified Ross score, mean pulmonary artery pressure, oxygen extraction rate (OER), and Ln NT-pro-BNP, but negatively correlated with age, oxygen delivery and its components, and estimated glomerular filtration rate (eGFR). Multiple linear regression analysis revealed significant correlation of GDF 15 levels with the modified Ross score, OER, and eGFR. Conclusions GDF 15 mainly reflects oxygen demand–supply relationship and can be used as a diagnostic marker of HF in unrepaired CHD with left to right shunt for a wide range of age and diagnoses.

Background & Aims Non-alcoholic steatohepatitis (NASH) is associated with the dysregulation of lipid metabolism and hepatic inflammation. The causal mechanism underlying NASH is not fully elucidated. This study investigated the role of β-Arrestin1 (ARRB1) in the progression of NASH. Methods Liver tissue from patients with NASH and controls were obtained to evaluate ARRB1 expression. NASH models were established in Arrb1-knockout and wild-type mice fed either a high-fat diet (HFD) for 26 weeks or a methionine/choline-deficient (MCD) diet for 6 weeks. Results ARRB1 expression was reduced in liver samples from patients with NASH. Reduced Arrb1 levels were also detected in murine NASH models. Arrb1 deficiency accelerated steatohepatitis development in HFD-/MCD-fed mice (accompanied by the upregulation of lipogenic genes and downregulation of β-oxidative genes). Intriguingly, ARRB1 was found to interact with growth differentiation factor 15 (GDF15) and facilitated the transportation of GDF15 precursor (pro-GDF15) to the Golgi apparatus for cleavage and maturation. Treatment with recombinant GDF15 ablated the lipid accumulation in the presence of Arrb1 deletion both in vitro and in vivo. Re-expression of Arrb1 in the NASH models ameliorated the liver disease, and this effect was greater in the presence of pro-GDF15 overexpression. By contrast, the effect of pro-GDF15 overexpression alone was impaired in Arrb1-deficient mice. In addition, the severity of liver disease in patients with NASH was negatively correlated with ARRB1 expression. Conclusion ARRB1 acts as a vital regulator in the development of NASH by facilitating the translocation of GDF15 to the Golgi apparatus and its subsequent maturation. Thus, ARRB1 is a potential therapeutic target for the treatment of NASH. Lay summary Non-alcoholic steatohepatitis (NASH) is associated with the progressive dysfunction of lipid metabolism and a consequent inflammatory response. Decreased ARRB1 is observed in patients with NASH and murine NASH models. Re-expression of Arrb1 in the murine NASH model ameliorated liver disease, an effect which was more pronounced in the presence of pro-GDF15 overexpression, highlighting a promising strategy for NASH therapy.

Ferroptosis is an iron-dependent form of regulated cell death. GDF15 affects various properties of cancer cells, but the role of GDF15 in ferroptosis has not been reported. In the present study, we found that GDF15 knockdown led to decreased expression of SLC7A11, which is a key component of system Xc− and a regulator of ferroptosis, indicating that GDF15 might play important roles in ferroptosis. CCK8 assay showed that GDF15 knockdown promoted erastin-induced ferroptosis in MGC803 cells. qRT-PCR and western blotting results demonstrated that GDF15 inhibition attenuated the increased SLC7A11 expression induced by erastin. Further study revealed that GDF15 knockdown promoted the decreased level of extracellular glutamate and intracellular GSH as well as the increased level of lipid ROS in the presence of erastin in MGC803 cells. Overall, the study shows that GDF15 knockdown promotes erastin-induced ferroptosis in MGC803 cells by attenuating the expression of SLC7A11 and the function of system Xc−.

Summary Background & aims Pro-inflammatory biomarkers are well-established contributors to insulin resistance and represent valid targets for diabetes management and prevention. Yet, little is known whether nutrition could play a role in modulating various aspects of immune-inflammatory responses. Our aim is to assess the effect of isocaloric animal and plant protein dietary interventions on selected biomarkers representing various immune-inflammatory pathways. Methods We enrolled 37 participants with type 2 diabetes (age 64 ± 6 years, body mass index 30.2 ± 3.6 kg/m2, glycated hemoglobin 7.0 ± 0.6%) who underwent an either high-animal protein (AP) or high-plant protein (PP) diet (30 E% protein, 40 E% carbohydrates, 30 E% fat) for 6-weeks. Clinical examinations were performed at beginning and end of the study. Levels of pro-inflammatory adipokines [chemerin, progranulin], cytokines [tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), soluble urokinase-type plasminogen activator receptor (suPAR), transforming growth factor beta 1 (TGF-β1)], and proteins [calprotectin, lactoferrin and growth differentiation factor 15 (GDF-15)] were determined in blood serum using enzyme-linked immunosorbent assay. Results Chemerin and progranulin concentrations decreased following AP and PP diets. TGF-β1 increased in AP and decreased in PP, whereas calprotectin increased in PP and decreased in AP. No statistically significant differences in the concentrations of IL-6, TNF-α, suPAR, lactoferrin and GDF-15 could be seen in either of the protein diet arms. Conclusions These results suggest that both AP and PP diets may effectively reduce the levels of the pro-inflammatory adipokines chemerin and progranulin. The effects on the additional immune-inflammatory biomarkers seem to be more complex. Clinical trial registry number NCT02402985 ( ww.clinicaltrials.gov ).

Growth Differentiation Factor 15 (GDF15) is seemingly involved in appetite control. Acute exercise increases GDF15 concentrations in lean humans, but acute and long-term effects of exercise on GDF15 in individuals with overweight/obesity are unknown. We investigated the effects of acute exercise and exercise training on GDF15 concentrations in individuals with overweight/obesity and associations with appetite and cardiometabolic markers. 90 physically inactive adults (20–45 years) with overweight/obesity were randomized to 6-months habitual lifestyle (CON, n=16), or isocaloric exercise of moderate (MOD, n=37) or vigorous intensity (VIG, n=37), 5 days/week. Testing was performed at baseline, 3, and 6 months. Plasma GDF15 concentrations, other metabolic markers, and subjective appetite were assessed fasted and in response to acute exercise before an ad libitum meal. Cardiorespiratory fitness, body composition, insulin sensitivity, and intraabdominal adipose tissue were measured. At baseline, GDF15 increased 18% (95%CI: 4; 34) immediately after acute exercise and 32% (16; 50) 60 min post-exercise. Fasting GDF15 increased 21% (0; 46) in VIG after 3 months (p=0.045), but this attenuated at 6 months (13% (−11; 43), p=0.316) and was unchanged in MOD (11% (−6; 32), p=0.224, across 3 and 6 months). Post-exercise GDF15 did not change in MOD or VIG. GDF15 was not associated with appetite or energy intake. Higher GDF15 was associated with lower cardiorespiratory fitness, central obesity, dyslipidemia, and poorer glycemic control. In conclusion, GDF15 increased in response to acute exercise but was unaffected by exercise training. Higher GDF15 concentrations were associated with a less favorable cardiometabolic profile but not with markers of appetite. This suggests that GDF15 increases in response to acute exercise independent of training state. Whether this has an impact on free-living energy intake and body weight management needs investigation.

The peptide hormone GDF15 is a potent anorectic factor. Raised circulating levels of GDF15 are seen in a large number of pathological disorders and are associated invariably with adverse clinical outcomes. GDF15 signalling is mediated through GFRAL receptor in the hindbrain. A greater understanding of the mechanisms that drive expression of GDF15 within different tissues has led to the GDF15-GFRAL axis being considered a route through which somatic distress is signalled to the brain. We highlight key recent insights into the role of GDF15 in appetitive behaviour and reflect on the therapeutic potential of the system for disorders of energy balance.

The aim of this study was to assess the association between serum growth differentiation factor-15(GDF-15) and 3-month depression after acute ischemic stroke.In this single-center prospective study, patients with first-ever acute ischemic stroke between March 2017 and November 2018 were included. Neurological and neuropsychological evaluations were conducted during the 3-month follow-up. The predictive value of GDF-15 to predict the post-stroke depression (PSD) within 3 months, was compared with other known predictors.The median level of GDF-15 in 310 stroke patients was 1285(IQR, 846-1934) ng/l. During the 3-month follow-up, 76 patients were defined as depression (24.5%; 95% confidence interval [CI]: 17.9%-29.3%), and GDF-15 levels in those patients were nearly more than 1 time greater as compared with patients who were free of depression (P 0.001). Using the ROC curves, GDF-15 serum level at 1660 ng/l predicted the PSD with the highest sensitivity and specificity [67.1% and 77.4%, respectively; AUC=0.78, 95%CI: 0.72-0.84; P 0.001]. Interestingly, When GDF-15 was added to the model containing established significant risk factors, AUROC (standard error) was increased from 0.81(0.029) to 0.88(0.020). A significant difference in the AUC between the established risk factors alone and the addition of GDF-15 was observed (difference, 0.07[0.009]; P = 0.001). In a multivariate model using the elevated levels of GDF-15 (≥cut-off=1660 ng/l) vs. normal (cut-off) together with the other significant clinical variables, the marker displayed predictive information (PSD: OR = 4.11 [95% CI, 2.05-6.32]; P 0.001]).In summary, GDF-15 serum levels at admission are associated with depression later developed in patients with ischemic stroke.

Background Atopic dermatitis (AD) is associated with increased systemic inflammation and cardiovascular risk. Although previous studies have found increased inflammatory proteins in the blood of patients with AD, detailed comparison among patients with AD of different ages is unavailable. Objective To characterize the blood proteomic signature of patients with AD as a function of age. Methods We used the OLINK high-throughput proteomic assay to measure serum inflammatory and cardiovascular risk proteins in 71 patients with moderate to severe AD from 3 age groups (18-40 years old [n = 26], 41-60 years old [n = 24], and >60 years old [n = 21]) compared with 37 age-matched controls. Total and allergen-specific serum IgEs were also measured. Results When we compared patients with AD from 3 different age groups with their respective controls, we identified a total of 172 differentially expressed proteins. TH2 chemokines (CCL13, CCL17) were consistently elevated in patients with AD across all ages (P 60 years old) exhibited striking upregulation of key proinflammatory proteins, including markers of atherosclerosis (CCL4, CCL7, SORT1), cardiovascular risk (GDF15, MPO, ST2), cell adhesion (CDH3), and apoptosis (FAS; all P Conclusion Elderly patients with AD had increased levels of systemic inflammatory markers, including those associated with cardiovascular and atherosclerosis risk, which may explain their increased incidence of cardiovascular disease. This finding suggests that older patients with AD may benefit from cardiovascular disease screening and prevention.

Atrial fibrillation (AF) is a source of altered brain perfusion and ischemia, potentially leading to cerebral injury and blood brain barrier (BBB) disruption, which may result in the permeation of neurospecific molecules into the bloodstream. We retrospectively analyzed circulating levels of biomarkers of cerebral injury: Astrocyte-specific glial acidic fibrillary protein (GFAP), calcium-binding protein B (S100 b), stress response marker growth differential factor 15 (GDF15), and microtubule associated Tau protein, in patients with AF and non-AF controls. A total of 196 AF cases and 47 non-AF controls were enrolled in this study all without previous clinical stroke or cerebral injury. Plasma samples were obtained from the Intermountain INSPIRE biobank registry. AF status was determined at the time of the sample draw using clinical diagnosis. Assessment of circulating biomarkers was conducted with EIA. Multivariate linear modeling, using natural log, and square root transformation of the biomarkers, was done adjusting for (1) CHA2DS2-VASc and anticoagulation, and (2) age, gender, coronary artery disease and anticoagulation. Circulating Tau, GDF15, and GFAP were elevated in AF cases. After multivariate adjustment, GFAP and Tau remained significantly elevated in the AF, whereas the signal for GDF15 was confounded by age. In conclusion, circulating biomarkers of neuronal and glial injury Tau and GFAP are elevated in patients with AF that are consistent with subclinical cerebral injury and disruption of the BBB, which can predispose these patients to the development of cognitive dysfunction and/or dementia later in life.

BACKGROUND Growth differentiation factor 15 (GDF15) is markedly increased in end-stage kidney disease and has been related to increased mortality in patients on dialysis. We hypothesized that kidney transplantation would decrease both GDF15 and N-terminal pro-B-type natriuretic peptide (NT-proBNP) and that GDF-15 decrease relates to post-kidney transplantation allograft function. METHODS End-stage kidney disease patients on dialysis awaiting a living donor kidney transplantation (n = 39), and those expected to be on the deceased donor waitlist for at least 12 months (n = 43) were enrolled at three transplant centers. Serum GDF15 and NT-proBNP were measured at 0, 3, and 12 months post-kidney transplantation or post-enrollment. Change in serum GDF15 and NT-proBNP concentrations, and their relation to estimated glomerular filtration rate (eGFR) were assessed by non-parametric tests and regression analyses. RESULTS Median baseline GDF15 was 4744 pg/ml and 5451 pg/ml for the kidney transplantation and dialysis groups, respectively (p = 0.09). Kidney transplantation resulted in a significant decrease in GDF15 (month 12 median 1631 pg/ml, p

Background To assess the prognostic performance of Growth differentiation factor-15 (GDF-15) concentrations in unselected patients presenting with suspected acute myocardial infarction (AMI) and adjudication based on high-sensitivity cardiac troponin (hs-cTn). Methods and results In an ongoing prospective multicenter diagnostic study, consecutive patients presenting with suspected AMI to the emergency department and available GDF-15 and hs-cTnT concentrations were included. Adjudication of AMI was performed central by two independent cardiologists using all available clinical information including cardiac imaging and serial hs-cTn concentrations. Overall, 718 patients were included, with 23% (162/718) having an adjudicated diagnosis of AMI. The cumulative incidence of death within 2 years was 19% in patients with AMI (30 deaths in 162 patients) versus 5% in patients without AMI (25 deaths in 556 patients; P Conclusions GDF-15 concentrations at emergency department presentation have a high predictive accuracy for all-cause death in patients with suspected AMI and allow the identification of a large proportion of AMI patients with very low mortality risk.

Early prognostication in post-cardiac arrest (CA) patients remains challenging and biomarkers have evolved as helpful tools in risk assessment. The stress-response cytokine growth differentiation factor-15 (GDF-15) is dramatically up-regulated during various kinds of tissue injury and predicts outcome in many pathological conditions. We aimed to assess the predictive value of circulating GDF-15 in post-CA patients.This prospective observational study included 128 consecutive patients (median age 60.3 years, 75.8% male) with return of spontaneous circulation after in- or out-of-hospital CA who were treated at a tertiary university hospital. GDF-15 serum levels were determined at admission.A total of 52 patients (40.6%) died during the 6-month follow-up. Median GDF-15 levels were significantly lower in survivors (1601 ng/L (interquartile range: 1114-2983 ng/L) than in non-survivors (3172 ng/L (1927-8340 ng/L); p 0.001). GDF-15 levels were also significantly lower in patients with favourable neurological 6-month outcome (cerebral performance category (CPC) 1-2) than in those with poor neurological outcome (CPC 3-5; p 0.001). GDF-15 significantly predicted 6-month mortality in univariate Cox regression analysis (hazard ratio (HR) per 1-standard deviation increase 1.76 [95% confidence interval (CI) 1.35-2.31; p 0.001] and remained significant after multivariable adjustment (HR 1.57 [95% CI 1.19-2.07; p = 0.001]). Subgroup analysis revealed that the association between GDF-15 and 6-month outcome was present both in patients with in- and out-of-hospital CA.GDF-15 predicts poor survival and neurological outcome in post-CA patients. GDF-15 may reflect the extent of hypoxic injury to the brain and other organs and might help to improve early risk stratification after CA.

The clinical manifestations of Sickle Cell Disease (SCD) include episodes of vascular occlusion, chronic hemolytic anemia and frequent infections. GDF-15, a multifactorial cytokine, is a member of the transforming growth factor- superfamily. Expression of the GDF-15 gene in cardiomyocytes, vascular smooth muscle cells, and endothelial cells is strongly upregulated in response to oxidative stress, inflammation and tissue injury, while high levels of serum GDF-15 associate with ineffective erythropoiesis and may reflect a certain type of bone marrow stress or erythroblast apoptosis. In this context we aimed to evaluate GDF-15 levels in 89 patients with HbS/βthal at steady phase and in 20 apparently healthy individuals, and correlate with clinical features of the disease and markers of hemolysis, iron burden, inflammation, coagulation and endothelial dysfunction. We found that: GDF-15 levels were elevated in patients with HbS/βthal compared to controls (1980.7 ± 159.8 vs 665.4 ± 50.9 pg/mL, p

Growth Differentiation Factor 15 (GDF15), also known as NSAID activated gene-1 (NAG-1), is associated with a large number of biological processes and diseases, including cancer and obesity. GDF15 is synthesized as pro-GDF15, is dimerized, and is cleaved and secreted into the circulation as a mature dimer GDF15. Both the intracellular GDF15 and the circulating mature GDF15 are implicated in biological processes, such as energy homeostasis and body weight regulation. Although there have been many studies on GDF15, GFRAL, a member of the glial-derived neurotropic factor receptor α family, has only been recently identified as a receptor for mature GDF15. In this review, we focused on cancer and energy homeostasis along with obesity and body weight, and the effect of the identification of the GDF15 receptor in these investigations. In addition, the therapeutic potential of GDF15 as a pharmacological agent in obesity and other metabolic diseases was discussed.

Background and aims Growth differentiation factor 15 (GDF15) is a strong predictor of cardiovascular morbidity and mortality found to be both marker and target of impaired glucose metabolism. GDF15 increases following glucose administration and is up-regulated in obesity and diabetes. We investigate here the relationship between GDF15 and beta cell function. Methods and results In this cross-sectional study we evaluated GDF15 concentrations in 160 obese subjects (BMI 35–63 kg/m2, age 39.4 ± 18.6 years, m/f 38/122) who underwent a 75 g oral glucose tolerance test (OGTT). Based on the OGTT results, the cohort was divided into two groups: 1) normal fasting glucose and normal glucose tolerance (n = 80), 2) impaired fasting glucose, impaired glucose tolerance or type 2 diabetes (n = 80). The relationship of GDF15 to fasting and OGTT-based dynamic insulin sensitivity and insulin secretion parameters was evaluated. GDF15 was higher in the prediabetes and diabetes groups and correlated with HbA1c, glucose, insulin as well as baseline and dynamic indices of insulin sensitivity and estimated beta cell function. Multiple regression analysis revealed that age, waist-to-height ratio, glomerular filtration rate and prehepatic beta cell function, but not the grade of impairment of glucose metabolism, were independent predictors of GDF15. Subgroup analysis showed that of all parameters of glucose metabolism only C-peptide, fasting prehepatic beta cell function and insulinogenic index remained significantly related to GDF15 in both groups. Conclusion We conclude that in patients with severe obesity, GDF15 strongly relates to beta cell function and should be further investigated as a potential therapeutic target and biomarker guiding treatment options.

Background Growth differentiation factor 15 (GDF15) is a key regulator of body weight in animals by regulating food intake. Its receptor, glial cell-derived neurotrophic factor receptor alpha-like (GFRAL), was identified recently. Pre-clinical studies showed that it is a promising therapeutic target for cardiometabolic diseases and anorexia/cachexia. Although many pharmaceutical companies are developing drugs targeting GFRAL, whether the findings from animal studies can be extrapolated to man is unknown. Mendelian randomization (MR) is useful in investigating the relationship between risk factors and disease outcomes. We aimed to use a two-sample MR approach to evaluate the clinical usefulness of targeting GDF15 for cardiometabolic diseases. Methods Genetic instruments and summary statistics for MR analyses were obtained from a large genome-wide association study (GWAS) of GDF15 and cardiometabolic outcomes (n = 27,394 to 644,875), including body mass index, waist-hip ratio, waist circumference, whole-body lean mass, fat percentage, Type 2 Diabetes, fasting glucose, glycated haemoglobin, fasting insulin, LDL-cholesterol, HDL-cholesterol, total cholesterol, triglycerides, coronary artery disease, and estimated BMD (eBMD). Conventional inverse variance weighted (IVW) method was adopted to obtain the causal estimates of GDF-15 with different outcomes; weighted median and MR-egger were used for sensitivity analyses. Findings There was null association between GDF15 levels and anthropometric outcomes. One SD increase in genetically-determined GDF15 was significantly associated with reduced HDL-C (beta: -0.048SD; SE: 0.014; P = .001) but the result was not significant in sensitivity analyses. A consistent significant causal association was observed between GDF15 and eBMD in IVW (beta: 0.026 SD; SE: 0.005; P

Growth differentiation factor 15 (GDF15) is recently emerging not only as a stress-related mitokine, but also as a key player in the aging process, being one of the most up-regulated protein with age and associated with a variety of age-related diseases (ARDs). Many data indicate that GDF15 has protective roles in several tissues during different stress and aging, thus playing a beneficial role in apparent contrast with the observed association with many ARDs. A possible detrimental role for this protein is then hypothesized to emerge with age. Therefore, GDF15 can be considered as a pleiotropic factor with beneficial activities that can turn detrimental in old age possibly when it is chronically elevated. In this review, we summarize the current knowledge on the biology of GDF15 during aging. We also propose GDF15 as a part of a dormancy program, where it may play a role as a mediator of defense processes aimed to protect from inflammatory damage and other stresses, according to the life history theory.

Rationale & Objective Inflammation, cardiac remodeling, and fibrosis may explain in part the excess risk for cardiovascular disease (CVD) in patients with chronic kidney disease (CKD). Growth differentiation factor 15 (GDF-15), galectin 3 (Gal-3), and soluble ST2 (sST2) are possible biomarkers of these pathways in patients with CKD. Study Design Observational cohort study. Setting & Participants Individuals with CKD enrolled in either of 2 multicenter CKD cohort studies: the Seattle Kidney Study or C-PROBE (Clinical Phenotyping and Resource Biobank Study). Exposures Circulating GDF-15, Gal-3, and sST2 measured at baseline. Outcomes Primary outcome was all-cause mortality. Secondary outcomes included hospitalization for physician-adjudicated heart failure and the atherosclerotic CVD events of myocardial infarction and cerebrovascular accident. Analytic Approach Cox proportional hazards models used to test the association of each biomarker with each outcome, adjusting for demographics, CVD risk factors, and kidney function. Results Among 883 participants, mean estimated glomerular filtration rate was 49±19mL/min/1.73m2. Higher GDF-15 (adjusted HR [aHR] per 1-SD higher, 1.87; 95% CI, 1.53-2.29), Gal-3 (aHR per 1-SD higher, 1.51; 95% CI, 1.36-1.78), and sST2 (aHR per 1-SD higher, 1.36; 95% CI, 1.17-1.58) concentrations were significantly associated with mortality. Only GDF-15 level was also associated with heart failure events (HR per 1-SD higher, 1.56; 95% CI, 1.12-2.16). There were no detectable associations between GDF-15, Gal-3, or sST2 concentrations and atherosclerotic CVD events. Limitations Event rates for heart failure and atherosclerotic CVD were low. Conclusions Adults with CKD and higher circulating GDF-15, Gal-3, and sST2 concentrations experienced greater mortality. Elevated GDF-15 concentration was also associated with an increased rate of heart failure. Further work is needed to elucidate the mechanisms linking these circulating biomarkers with CVD in patients with CKD.

The aim of this study was to investigate whether treatment-damaged hepatocellular carcinoma (HCC) would accelerate liver cirrhosis through promoting the activities of hepatic stellate cells (HSCs). HCC cells were exposed to chemotherapeutic agent or hypoxia to mimic the transarterial chemoembolization (TACE)-like treatment. Growth differentiation factor 15 (GDF15) expression was increased in cisplatin- or hypoxia-treated HCC cells. Treatment-induced GDF15 increase in HCC cells was mediated by p38MAPK, JNK, ERK1/2 activation. GDF15 from treatment-damaged HCC cells enhanced the proliferation and collagen synthesis of HSCs through ERK1/2- and Smad3-dependent pathways. Metformin significantly reduced the GDF15 production from treatment-damaged HCC cells by targeting JNK. The use of metformin could attenuate the in vivo fibrotic activities of HSCs promoted by treatment-damaged HCC cells and inhibit GDF15 expression. In conclusion, treatment-damaged HCC accelerates fibrosis by promoting the activities of HSCs via GDF15 secretion, which could be reversed by metformin. This provides a potential therapeutic target for alleviating TACE-aggravated liver cirrhosis.

MIC-1/GDF15 is a stress response cytokine and a distant member of the transforming growth factor beta (TGFb) superfamily, with no close relatives. It acts via a recently identified receptor called glial-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL), which is a distant orphan member of the GDNF receptor family that signals through the tyrosine kinase receptor Ret. MIC-1/GDF15 expression and serum levels rise in response to many stimuli that initiate cell stress and as part of a wide variety of disease processes, most prominently cancer and cardiovascular disease. The best documented actions of MIC-1/GDF15 are on regulation of energy homeostasis. When MIC-1/GDF15 serum levels are substantially elevated in diseases like cancer, it subverts a physiological pathway of appetite regulation to induce an anorexia/cachexia syndrome initiated by its actions on hindbrain neurons. These effects make it a potential target for the treatment of both obesity and anorexia/cachexia syndromes, disorders lacking any highly effective, readily accessible therapies.

Endothelial progenitor cells (EPCs) display pro-angiogenic properties that confer to them a therapeutic potential for treating ischemic lesions. In culture, EPCs generate Endothelial Colony Forming Cells (ECFCs) that have endothelial features but still retain properties of stem/progenitor cells. EPCs can be obtained either from cord blood (CB) or adult blood (AB). For clinical perspectives, both CB-ECFCs and AB-ECFCs have advantages and inconveniences. On one hand, CB-ECFCs are allogenic, with potential immune rejection, but are more clonogenic, proliferative and angiogenic than AB-ECFCs. We have found that these cells display high inter-individual variation in terms of clonogenic profile. Low clonogenic CB-ECFCs had functional properties similar to those of AB-ECFCs. Conversely, a high initial clonogenicity was associated to an enhanced proliferation, angiogenic potential and to an increased expression of genes linked to stem cell-ness. Selecting CB-ECFCs according the initial clonogenicity represent a relevant marker of their potential efficacy on vascular repair. On the other hand, AB-ECFCs are autologous, and should be immunologically well tolerated, but these cells give rise to only few colonies, proliferate less and are less angiogenic than CB-ECFCs. In order to go further in CB-/AB- characterization, we have analyzed the mechanisms of AB-ECFC premature senescence, and shown that GDF15 had pivotal role in this context. Taken together, these new data constitute important steps toward clinical use of EPCs. Keywords: Endothelial progenitor cells, Stem cells, Clonogenicity, Senescence, GDF15

The adaptive unfolded protein responses (UPR) initiated by ER stress have been implicated in metabolic dysfunctions and liver diseases. Growth differentiation factor 15 (GDF15) shows a broad range of effects on lipid homeostasis. The functional interconnections between ER stress and GDF15 are still unclear, however. Here we present that hepatic excess lipid accumulation along with ER stress could exacerbate GDF15 expression in mouse liver. Administration of chemical ER stressor tunicamycin to activate the UPR pathway resulted in robust increase of hepatic and circulating GDF15 levels. Further studies revealed that C/EBP-homologous protein (CHOP) of the UPR pathway could directly bind to the promoter of GDF15 and activate its transcription under ER stress conditions both ex vivo and in vivo. Ectopic expression of hepatic GDF15 reduced lipid accumulation in liver and alleviated non-alcoholic fatty liver disease (NAFLD) progression via enhancing hepatic fatty acid β-oxidation in HFD-feeding mice. Together, our results demonstrate that hepatic GDF15 acts as a downstream component of the UPR program and exerts beneficial functions in regulating lipid metabolism of liver.

During infection, disease tolerance promotes host health without killing the pathogen. In a recent issue of Cell, Luan et al. (2019) identify GDF15 as a central regulator of disease tolerance of bacterial and viral challenges, while preventing cardiac damage, by mediating downstream cross-organ communication via the sympathetic and metabolic systems.

Pancreatic beta cell dysfunction is a hallmark of type 2 diabetes. Growth differentiation factor 15 (GDF15), which is an energy homeostasis regulator, has been shown to improve several metabolic parameters in the context of diabetes. However, its effects on pancreatic beta-cell remain to be identified. We, therefore, performed experiments using cell models and histological sectioning of wild-type and knock-out GDF15 mice to determine the effect of GDF15 on insulin secretion and cell viability. A bioinformatics analysis was performed to identify GDF15-correlated genes. GDF15 prevents glucotoxicity-mediated altered glucose-stimulated insulin secretion (GSIS) and connexin-36 downregulation. Inhibition of endogenous GDF15 reduced GSIS in cultured mouse beta-cells under standard conditions while it had no impact on GSIS in cells exposed to glucolipotoxicity, which is a diabetogenic condition. Furthermore, this inhibition exacerbated glucolipotoxicity-reduced cell survival. This suggests that endogenous GDF15 in beta-cell is required for cell survival but not GSIS in the context of glucolipotoxicity.

Summary: The age-related effects of GDF11 have been a subject of controversy. Here, we find that elevated GDF11 causes signs of cachexia in mice: reduced food intake, body weight, and muscle mass. GDF11 also elicited a significant elevation in plasma Activin A, previously shown to contribute to the loss of skeletal muscle. The effects of GDF11 on skeletal muscle could be reversed by administration of antibodies to the Activin type II receptors. In addition to the effects on muscle, GDF11 increased plasma GDF15, an anorectic agent. The anorexia, but not the muscle loss, could be reversed with a GDF15-neutralizing antibody. GDF15 upregulation is due to GDF11-induced recruitment of SMAD2/3 to the GDF15 promoter. Inhibition of GDF15 can restore appetite but cannot restore the GDF11-induced loss of muscle mass, which requires blockade of ActRII signaling. These findings are relevant for treatment of cachexia.

Weight loss from caloric restriction (i.e. dieting) tends to be modest and short-lived, whereas from bariatric surgeries such as Roux-en-Y gastric bypass (RYGB) is pronounced and generally sustained. The reasons behind these opposing outcomes between interventions remain unclear, but likely involve differential effects on gut-brain communication. Growth differentiation factor 15 (GDF15) is a ubiquitously-induced, centrally-acting, anorexigenic cytokine whose systemic levels are elevated under a variety of conditions associated with a negative energy balance, including in patients following RYGB. We therefore asked whether systemic and portal vein GDF15 levels differ between obese Zucker fatty rats that experienced similar weight loss from RYGB or from forced caloric restriction (CR). Compared with ad libitum fed (ALF) controls, body weight, visceral adiposity and food intake of RYGB and CR rats were markedly lower during the postoperative observation period. Both systemic and portal vein GDF15 levels in RYGB rats at postoperative day 28 were higher compared with ALF rats and particularly compared with CR rats. Further, systemic and portal vein GDF15 levels negatively correlated with body weight and food intake specifically in RYGB rats. These findings provide evidence that, unlike dieting, RYGB might achieve sustained weight loss and appetite suppression partly through increased GDF15 release from epithelial cells of the gastrointestinal tract.

Growth differentiation factor-15 (GDF-15) is a cytokine upregulated in multiple pathological conditions where oxidative stress, endothelial dysfunction, tissue aging, and chronic inflammation are the hallmarks. GDF-15 has many sources of production, including cardiac and vascular myocytes, endothelial cells, adipocytes and macrophages in response to metabolic stress, oncogenic transformation and the burden of proinflammatory cytokines or reactive oxygen species. Although the main sources of GDF-15 are extracardiac tissues, it has been shown to be elevated in many cardiac disorders. In experimental models of heart disease, GDF-15 release is induced after an ischemic insult and in pressure overload scenarios. Likewise, in recent years, an increasing body of evidence has emerged linking GDF-15 to the risk of mortality in acute coronary syndromes, atrial fibrillation and heart failure. Additionally, GDF-15 has been shown to add prognostic information beyond other conventional biomarkers such as natriuretic peptides and cardiac troponins. Further studies are needed to assess whether the incorporation of GDF-15 into clinical practice can improve cardiovascular outcomes.

Male premature neonates are more susceptible than females to the development of bronchopulmonary dysplasia (BPD). The reasons underlying sexually dimorphic outcomes in premature neonates are not known. GDF15 (Growth and differentiation factor 15) is a secreted cytokine and plays a role in cell proliferation, apoptosis, and angiogenesis. In this study, we sought to elucidate the sex-specific expression of Gdf15 in the lung in vivo in neonatal hyperoxic lung injury and its regulation by Hif-1α, and to delineate the differences in GDF15 expression in male and female human umbilical venous endothelial cells in an in vitro model of oxygen toxicity. Following hyperoxia exposure (95% FiO2, PND (postnatal day 1-5: saccular stage of lung development), neonatal male mice (C57BL/6) show increased GDF15 and decreased HIF-1α expression compared to female mice. For the in vitro experiments, male and female HUVECs were exposed to room air condition (21% O2, 5% CO2) or in hyperoxia condition (95% O2, 5% CO2) for up to 72 h. Male HUVECs had greater expression of GDF15 mRNA and protein. To study the inter-relationship between GDF15 and HIF-1α, we measured the expression of GDF15 in H441 cells after HIF-1α knockdown using promoter dual luciferase reporter assay, which showed that HIF-1α and GDF15 expression are inversely related under normoxia and hyperoxia. The results indicate that sex differences exist in the expression and modulation of GDF15 by HIF-1α in neonatal hyperoxic injury both in vivo and in vitro. These differences could explain in part the mechanisms behind sex-specific differences in BPD.

Heart failure (HF) with reduced ejection fraction remains a major therapeutic challenge. The aim of this study was to investigate the role of novel cardiovascular biomarkers, i.e. soluble suppression of tumorigenicity (sST2), growth-differentiation factor-15 (GDF-15), soluble urokinase plasminogen activator receptor (suPAR) and heart-type fatty acid binding protein (H-FABP) in patients with ischaemic (ICM) or dilative cardiomyopathy (DCM).A total of 200 patients were enrolled in this study: 65 were diagnosed with DCM and 59 patients suffering from ICM were included. 76 patients without coronary artery disease or signs of heart failure were included as controls. Plasma samples of all patients were analyzed by use of ELISA.Levels of sST2, suPAR and H-FABP were significantly higher in ICM and DCM patients compared to the control group (p0.0001). However, there were no significant differences between ICM and DCM in biomarker levels. Ejection fraction correlated inversely with cardiac biomarkers (sST2 p0.0001, GDF-15 p=0.0394, suPAR p=0.0029, H-FABP p0.0001). Similarly, CRP levels also showed a positive correlation with cardiac biomarkers. Renal insufficiency (p0.0001) and diabetes (sST2 p=0.0021, GDF-15 p=0.0055, suPAR p=0.0339, H-FABP p=0.0010) were significantly associated with a rise in cardiac biomarkers.Novel cardiovascular biomarkers such as ST2, GDF-15, uPAR and H-FABP could offer a great potential for more precise diagnostic in ICM and DCM patients. H-FABP was the most promising marker in our study, followed by sST2, uPAR and GDF-15. Additional prospective studies will be necessary to further evaluate the potential clinical benefits in routine treatment of HF.

To evaluate and validate the prognostic value of growth-differentiation factor 15 (GDF-15) beyond clinical characteristics and other biomarkers concerning bleeding and stroke outcomes in patients with atrial fibrillation in the RE-LY trial.GDF-15 was measured in samples collected at randomization in 8,474 patients with a median follow-up time of 1.9 years. Patients were stratified based on predefined GDF-15 cutoffs: group 1,1,200 ng/L (the 90th percentile in healthy individuals); group 2, 1,200-1,800; and group 3,1,800 ng/L (high-risk individuals). Efficacy and safety outcomes were compared across groups of GDF-15 in Cox models adjusted for baseline characteristics, cardiac (N-terminal pro-b-type natriuretic peptide, high-sensitive troponin T), inflammatory (interleukin 6, C-reactive protein) and coagulation (D-dimer) biomarkers, and randomized treatment.GDF-15 concentrations were1,200 ng/L in 2,647 (31.2%), between 1,200 and 1,800 ng/L in 2,704 (31.9%), and1,800 ng/L in 3,123 (36.9%) participants, respectively. Annual rates of stroke, major bleeding, and mortality increased with higher GDF-15 levels. The prognostic value of GDF-15 was independent of clinical characteristics for these outcomes. In models also adjusted for biomarkers, GDF-15 remained significantly associated with major bleeding (hazard ratio [95% CI] group 3 vs group 1 1.76 [1.28-2.42], P.0005) and all-cause mortality (hazard ratio 1.72 [1.30-2.29], P.0005). GDF-15 improved the c index of both the HAS-BLED (0.62-0.69) and ORBIT (0.68-0.71) bleeding risk scores.In patients with atrial fibrillation, GDF-15 is an independent risk indicator for major bleeding and all-cause mortality, but not for stroke. Therefore, GDF-15 seems useful as a specific marker of bleeding in patients with AF on oral anticoagulant treatment.

High viral load with liver injury is exhibited in severe dengue virus (DENV) infection. Mitogen activated protein kinases (MAPKs) including ERK1/2 and p38 MAPK were previously found to be involved in the animal models of DENV-induced liver injury. However, the role of JNK1/2 signaling in DENV-induced liver injury has never been investigated. JNK1/2 inhibitor, SP600125, was used to investigate the role of JNK1/2 signaling in the BALB/c mouse model of DENV-induced liver injury. SP600125-treated DENV-infected mice ameliorated leucopenia, thrombocytopenia, hemoconcentration, liver transaminases and liver histopathology. DENV-induced liver injury exhibited induced phosphorylation of JNK1/2, whereas SP600125 reduced this phosphorylation. An apoptotic real-time PCR array profiler was used to screen how SP600125 affects the expression of 84 cell death-associated genes to minimize DENV-induced liver injury. Modulation of caspase-3, caspase-8 and caspase-9 expressions by SP600125 in DENV-infected mice suggests its efficiency in restricting apoptosis via both extrinsic and intrinsic pathways. Reduced expressions of TNF-α and TRAIL are suggestive to modulate the extrinsic apoptotic signals, where reduced p53 phosphorylation and induced anti-apoptotic Bcl-2 expression indicate the involvement of the intrinsic apoptotic pathway. This study thus demonstrates the pivotal role of JNK1/2 signaling in DENV-induced liver injury and how SP600125 modulates this pathogenesis.

Background: Neurologic manifestations are well-recognized features of coronavirus disease 2019 (COVID-19). However, the longitudinal association of biomarkers reflecting CNS impact and neurological symptoms is not known. We sought to determine whether plasma biomarkers of CNS injury were associated with neurologic sequelae after COVID-19. Methods: Patients with confirmed acute COVID-19 were studied prospectively. Neurological symptoms were recorded during the acute phase of the disease and at six months follow-up, and blood samples were collected longitudinally. Healthy age-matched individuals were included as controls. We analysed plasma concentrations of neurofilament light-chain (NfL), glial fibrillary acidic protein (GFAp), and growth differentiation factor 15 (GDF-15). Findings: One hundred patients with mild (n = 24), moderate (n = 28), and severe (n = 48) COVID-19 were followed for a median (IQR) of 225 (187–262) days. In the acute phase, patients with severe COVID-19 had higher concentrations of NfL than all other groups (all p < 0·001), and higher GFAp than controls (p < 0·001). GFAp was also significantly increased in moderate disease (p < 0·05) compared with controls. NfL (r = 0·53, p < 0·001) and GFAp (r = 0·39, p < 0·001) correlated with GDF-15 during the acute phase. After six months, NfL and GFAp concentrations had normalized, with no persisting group differences. Despite this, 50 patients reported persistent neurological symptoms, most commonly fatigue (n = 40), “brain-fog” (n = 29), and changes in cognition (n = 25). We found no correlation between persistent neurological symptoms and CNS injury biomarkers in the acute phase. Interpretation: The normalization of CNS injury biomarkers in all individuals, regardless of previous disease severity or persisting neurological symptoms, indicates that post COVID-19 neurological sequelae are not accompanied by ongoing CNS injury. Funding: The Swedish State Support for Clinical Research, SciLifeLab Sweden, and the Knut and Alice Wallenberg Foundation have provided funding for this project.

Background: Recent studies noted that circulating growth differentiation factor 15 (GDF15) were closely related to metabolic states. The study aimed to explore the changes of GDF15 levels and their influencing factors after 4 weeks of lifestyle intervention (LI) or LI combined with breakfast meal replacement (LI+MR) in newly diagnosed type 2 diabetes patients. Methods: A total of 84 patients with available serum samples at both baseline and Week 4 were enrolled in this biomarker substudy. All subjects underwent a 2-hour 75g oral glucose tolerance test at baseline and Week 4. Serum GDF15 levels were determined by a sandwich enzyme-linked immunosorbent assay. Results: After 4-weeks of LI, GDF15 levels overall significantly decreased compared with baseline (Pr=–0.450, PConclusions: LI led to significantly decreased GDF15 levels among patients with newly diagnosed type 2 diabetes and its effect was more significant among patients with baseline GDF15 levels ≥900 pg/ml.Trial registration: ClinicalTrials.gov, NCT02248714. Registered 25 September 2014 - Retrospectively registered, https://www.clinicaltrials.gov/ct2/show/NCT02248714?term=NCT02248714&draw=2&rank=1

The ageing process is accompanied by the gradual development of chronic systemic inflammation (inflamm-ageing). Growth differentiation factor 15 (GDF15) is associated with inflammation and known to be a stress-induced factor. The present study aimed to explore the association of GDF15 with ageing. In this cross-sectional study, serum GDF15, hematological parameters, and biomedical parameters were determined in 120 healthy individuals (23-83 years old, males). Three telomere related parameters, including telomere length, telomerase activity, and the expression of human telomerase reverse transcriptase (hTERT) mRNA were also quantified. Our results showed that the older group has a higher levels of GDF15 and lower expression of hTERT mRNA, and PBMC telomerase activity (p 0.001). In individuals with high GDF15 levels, they were older, and presented with the lower level of hTERT mRNA and T/S ratio (p 0.01). Spearman correlation analysis shows that GDF15 positively correlated with age (r = 0.664, p 0.001), and negatively correlated with telomere length (r = -0.434, p 0.001), telomerase activity (r = -0.231, p = 0.012), and hTERT mRNA (r = -0.206, p = 0.024). Furthermore, in multivariate regression analysis, GDF15 levels showed a statistically significant linear and negative relationship with PBMC telomerase activity (β-coefficient = -0.583, 95% CI -1.044 to -0.122, p = 0.014), telomere length (β-coefficient = -0.200, 95% CI -0.305 to -0.094, p 0.001), and hTERT mRNA (β-coefficient = -0.207, 95% CI -0.312 to -0.102, p 0.001) after adjusting for confounders. These results support that circulating GDF15 is the potential biomarker of ageing that may influence the risk and progression of multiple ageing conditions.

Summary To investigate the molecular mechanisms underlying islet dysfunction and insulin resistance in diet-induced diabetes, we conducted temporal RNA sequencing of tissues responsible for insulin secretion (islets) and action (liver) every 4 weeks in mice on high-fat (HFD) or chow diet for 24 weeks, linking to longitudinal profile of metabolic characteristics. The diverse responses of α, β, and δ cells to glucose and palmitate indicated HFD-induced dynamic deterioration of islet function from dysregulation to failure. Insulin resistance developed with variable time course in different tissues. Weighted gene co-expression network analysis and Ingenuity Pathway Analysis implicated islets and liver jointly programmed β-cell compensatory adaption via cell proliferation at early phase and irreversible islet dysfunction by inappropriate immune response at later stage, and identified interconnected molecules including growth differentiation factor 15. Frequencies of T cell subpopulation showed an early decrement in Tregs followed by increases in Th1 and Th17 cells during progression to diabetes., Graphical abstract, Highlights • Diet-induced diabetes is featured by transition from islet dysfunction to failure • Insulin resistance develops with variable time course in different tissues • Dynamics of islet and liver molecular network interplay at different stages • T-cell-mediated immune response participates via priming and amplification phases, Animal Physiology ; Diabetology ; Transcriptomics

Background Mitochondria is a key organelle for energy production and cellular adaptive response to intracellular and extracellular stresses. Mitochondrial stress can be evoked by various stimuli such as metabolic stressors or pathogen infection, which may lead to expression of ‘mitokines’ such as growth differentiation factor 15 (GDF15). Scope of review This review summarizes the mechanism of GDF15 expression in response to organelle stress such as mitochondrial stress, and covers pathophysiological conditions or diseases that are associated with elevated GDF15 level. This review also illustrates the in vivo role of GDF15 expression in those stress conditions or diseases, and a potential of GDF15 as a therapeutic agent against metabolic disorders such as NASH. Major conclusions Mitochondrial unfolded protein response (UPRmt) is a critical process to recover from mitochondrial stress. UPRmt can induce expression of secretory proteins that can exert systemic effects (mitokines) as well as mitochondrial chaperons. GDF15 can have either protective or detrimental systemic effects in response to mitochondrial stresses, suggesting its role as a mitokine. Mounting evidence shows that GDF15 is also induced by stresses of organelles other than mitochondria such as endoplasmic reticulum (ER). GDF15 level is increased in serum or tissue of mice and human subjects with metabolic diseases such as obesity or NASH. GDF15 can modulate metabolic features of those diseases. General significance GDF15 play a role as an integrated stress response (ISR) beyond mitochondrial stress response. GDF15 is involved in the pathogenesis of metabolic diseases such as NASH, and also could be a candidate for therapeutic agent against those diseases.

Carcinogenesis is a multistep process in which cancer cells and tumor stroma cells play important roles. T lymphocytes are immune constituents of tumor stoma and play a crucial function in anti-tumor response. By immunohistochemistry and flow cytometry, we studied T cytotoxic (CTLs) and T helper lymphocyte distribution and percentage in the tumor microenvironment and peripheral blood from 35 patients with endometrioid endometrial carcinomas (EEC). We also studied 23 healthy donors' blood samples as a control group. Tumor and non-tumoral endometrium samples were obtained. Immunohistochemistry revealed a high number of CTLs and T helper lymphocytes in the tumor stoma of myoinvasive EECs. T lymphocytes were mostly located in the invasive front. By flow cytometry, the percentages of CTLs and T helper lymphocytes were significantly higher in the tumor compared with the non-neoplastic endometrium (P = .0492 and P = .002). The mean fluorescence intensity of CD8 staining was lower in the tumor compared to the non-neoplastic endometrium (P = .001). There was also reduction of the mean fluorescence intensity of CD8 staining on peripheral blood from patients with grade 3 EECs compare to the peripheral blood from healthy donors (P = .0093). No alterations in the expression of granzymes A and B were found in the CTLs from the EEC cases. Finally, in a proteome profiler cytokine array we found that the growth differentiation factor 15 (GDF15) increased in blood in parallel to the tumor grade. EECs are capable of down-regulating CD8 expression of CTLs. Most likely, this effect is mediated by a soluble molecule present in plasma and is not a result of anergy or exhaustion state. (C) 2016 Elsevier Inc. All rights reserved.

The effects of scopoletin on non-alcoholic fatty liver in obese mice were investigated. Mice were fed high-fat diet (HF) with or without two doses of scopoletin (0.01 and 0.05%, w/w) for 16 weeks. Both doses of scopoletin led to similar reductions in body weight, visceral fat, serum levels of leptin, lipid, TNFα, IL-6, IFNγ and MCP-1, insulin resistance and hepatic lipid accumulation, whereas they increased serum adiponectin and faecal lipid levels. Ingenuity pathway analysis revealed that hepatic gene networks related to lipid concentrations, inflammation of organs, quantity of adipose tissue, proliferation of cell and necrosis were down-regulated in the scopoletin group. The top up- or down-regulated genes were Cidea, Apoa4, Cyp7a1, Errfi1, Col1a1, Mmp13, Cdkn1a, Gdf15 and Saa1, which emerged as associated genes related to hepatic steatosis and inflammation. These results indicate that scopoletin may ameliorate HF-induced hepatic dysfunction via regulation of lipid metabolic and inflammatory genes.