Association between Growth Differentiation Factor 15 (GDF15) and Cardiovascular Risk in Patients with Newly Diagnosed Type 2 Diabetes Mellitus

Short Sleep and Insomnia Are Associated With Accelerated Epigenetic Age

OBJECTIVE

Short sleep and insomnia are each associated with a greater risk of age-related disease, which suggests that insufficient sleep may accelerate biological aging. We examine whether short sleep and insomnia alone or together relates to epigenetic age among older adults.

METHODS

A total of 3795 men (46.3%) and women aged 56 to 100 years from the Health and Retirement Study were included. Insomnia was defined as reporting at least one insomnia symptom (difficulty falling asleep, waking up at night, or waking up too early in the morning) and feeling unrested when waking up most of the time. Those reporting <6 hours of bedtime were categorized as short sleepers. Three second- or third-generation epigenetic age acceleration clocks were derived from the 2016 Health and Retirement Study Venous Blood Study. The linear regression analysis was adjusted for age, sex, race/ethnicity, education, and obesity status.

RESULTS

Insomnia and short sleep were associated with acceleration of GrimAge of 0.49 (95% confidence interval [CI] = 0.03-0.94 years; p = .04) and 1.29 (95% CI = 0.52-2.07 years; p = .002) years, respectively, as well as a faster pace of aging (DunedinPACE; 0.018 [95% CI = 0.004-0.033; p = .02] and 0.022 [95% CI = -0.004 to 0.048; p = .11]). Compared with healthy sleepers, individuals with the combination of short sleep and insomnia had an accelerated GrimAge (0.97 years; 95% CI = 0.07-1.87 years, p = .04) and a greater DunedinPACE (0.032; 95% CI = 0.003-0.060, p = .04).

CONCLUSIONS

Our findings indicate that short sleep, insomnia, and the combination of the two are linked to epigenetic age acceleration, suggesting that these individuals have an older biological age that may contribute to risk of comorbidity and mortality.

Evaluation of the relation between subclinical systolic dysfunction defined by four-dimensional speckle-tracking echocardiography and growth differentiation factor-15 levels in patients with acromegaly

PURPOSE

In patients with acromegaly, the long-term presence of elevated GH and IGF-1 levels is associated with an unfavorable cardiovascular risk profile. We aimed to assess the relationship of four-dimensional speckle tracking echocardiographic (4DSTE) measurements with growth differentiation factor-15 (GDF-15) levels and the Framingham Cardiovascular Risk Score (FRS) in patients with acromegaly.

METHODS

A single-center, cross-sectional study was conducted. The study included 40 acromegaly and 32 age- and gender-matched controls. Anthropometric, biochemical, and echocardiographic assessments were performed. GDF-15 levels were measured using ELISA.

RESULTS

In the controlled acromegaly group, global longitudinal (GLS), circumferential (GCS), area (GAS), and radial (GRS) strain measurements identified by 4DSTE were lower than those of the controls (p < 0.05). Moreover, strain parameters were lower in active acromegaly patients than in controls, but the difference was not statistically significant. The GLS was negatively correlated with age, the estimated disease duration, and FRS. Serum GDF-15 levels showed no significant difference between the acromegaly and control groups. In patients with acromegaly, serum GDF-15 levels were positively correlated with age, waist-to-hip ratio, systolic and diastolic blood pressure, FRS, fasting plasma glucose, and HbA1c, but not with strain parameters. The multiple regression analysis revealed that FRS was an independent factor associated with serum GDF-15 levels in patients with acromegaly and the overall cohort (p < 0.001).

CONCLUSION

Our study demonstrates that while LVEF was within normal limits, global strain parameters (GLS, GCS, GAS, and GRS) measured by using a novel imaging technique, 4DSTE, were lower in patients with acromegaly, suggesting the presence of subclinical systolic dysfunction in patients with acromegaly. GDF-15 can be a potential predictor of cardiovascular risk in patients with acromegaly.

Skin advanced glycation end-products as indicators of the metabolic profile in diabetes mellitus: correlations with glycemic control, liver phenotypes and metabolic biomarkers

INTRODUCTION

The production of advanced glycation end-products (AGEs) is a key pathomechanism related to the complications of diabetes mellitus. The measurement of HbA1c as one of the AGEs is widely used in the clinic, but also other proteins undergo glycation in the course of diabetes. Here, we measure skin AGEs (SAGEs) in patients with diabetes type 1 (DM1) and type 2 (DM2) and correlate them with metabolic markers as well as non-invasively measured liver fibrosis and steatosis.

PATIENTS AND METHODS

In this cross-sectional study, a total of 64 patients with either DM1 or DM2 and 28 healthy controls were recruited. SAGEs were measured using autofluorescence (AGE Reader). Liver fibrosis and steatosis were quantified using transient elastography, which determines liver stiffness measurement (LSM) and controlled attenuation parameter (CAP). FGF19, FGF21 and GDF-15 were measured in blood samples using ELISA.

RESULTS

SAGEs were elevated in both groups of patients with diabetes as compared to healthy controls (both p < 0.001) and were higher in patients with DM2 in comparison to DM1 (p = 0.006). SAGEs correlated positively with HbA1c (r = 0.404, p < 0.001), CAP (r = 0.260, p = 0.016) and LSM (r = 0.356, p < 0.001), and negatively with insulin growth factor binding protein 3 (p < 0.001). We also detected a positive correlation between GDF15 and SAGEs (r = 0.469, p < 0.001).

CONCLUSIONS

SAGEs are significantly elevated in patients with both DM types 1 and 2 and correlate with metabolic markers, including HbA1c and GDF15. They might also help to detect patients with advanced liver injury in the setting of diabetes.

Growth differentiation factor 15 (GDF-15) in endocrinology

Human growth differentiation factor 15 (GDF-15) is a widely distributed protein that has shown to play multiple roles in both physiological and pathological conditions. In healthy individuals, GDF-15 is mainly expressed in the placenta, followed by the prostate, although low levels of expression have also been detected in different organs. GDF-15 acts through a recently identified receptor called glial-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL) which signals through the rearranged during transfection (RET) tyrosine kinase receptor. The effects of GDF-15 are pleiotropic and include appetite regulation, and actions on metabolism, pregnancy, cell survival, immune response, and inflammation. GDF-15 also plays different roles in the pathophysiology of cardiovascular disease, autoimmunity, cancer-associated anorexia/cachexia, and diabetes. In recent years, several studies have reported a link between GDF-15 and the endocrine system. In this review, we up-date and summarize the relevant investigations of the relationships between GDF-15 and different endocrine conditions. We also assess the potential pathogenic role and potential therapeutic applications of GDF-15 in the field of endocrinology.

Growth differentiation factor‑15 in patients with gestational diabetes mellitus and its relationship with microalbuminuria

Gestational diabetes mellitus (GDM) is a common pregnancy-related complication and growth differentiation factor-15 (GDF-15) is involved in a number of diseases; therefore, the aim of the present study was to investigate the level and clinical significance of serum GDF-15 levels in patients with GDM. A total of 237 pregnant women at 20-24 weeks of gestation were selected and assigned to a normal pregnancy group (70 patients) and a GDM group (167 patients) according to the presence or absence of GDM. The general clinical data of the two groups were collected. Fasting plasma glucose, 1-h plasma glucose, 2-h plasma glucose, glycated hemoglobin, fasting insulin, 24-h urinary albumin and serum GDF-15 levels were measured. The results showed that the body mass index (BMI) of the GDM group was higher than that of the normal pregnancy group. Fasting plasma glucose, 1-h plasma glucose, 2-h plasma glucose, fasting insulin, glycated hemoglobin and GDF-15 levels and the positive rate of microalbuminuria were significantly higher in the GDM group compared with the normal pregnancy group. GDF-15 levels were positively correlated with BMI, fasting plasma glucose, glycated hemoglobin, homeostasis model assessment-insulin resistance and fasting insulin levels. Logistic regression analysis suggested that elevated GDF-15 levels are an independent risk factor for microalbuminuria. In conclusion, serum GDF-15 levels are strongly associated with GDM and elevated GDF-15 levels are an independent risk factor for microalbuminuria. Serum GDF-15 may act as a novel biomarker for predicting microalbuminuria in GDM patients.

Relationship Between Plasma Growth Differentiation Factor 15 Levels and Complications of Type 2 Diabetes Mellitus: A Cross-sectional Study

OBJECTIVE

Our aim in this study was to identify the associations between growth differentiation factor 15 (GDF15) and type 2 diabetes mellitus (T2DM) complications in a community-based population in China.

METHODS

Based on a cross-sectional study registered in the National Basic Public Health Service for disease management of Changshu in China, a total of 1,689 T2DM patients were enrolled and tested further for plasma GDF15 levels. Macrovascular (cardiovascular disease and diabetic foot) and microvascular (diabetic kidney disease [DKD], diabetic retinopathy, and neuropathy) complications were evaluated. Logistic regression models were conducted to identify the associations of GDF15 with the risk of diabetes complications, and linear regression models were used to assess relationships between GDF15 and other clinical features.

RESULTS

Overall, 459 of the 1,689 T2DM patients (27.18%) had complications. GDF15 levels were significantly higher in patients with any type of complication compared with their counterparts. With each standard deviation increase of base 10 logarithms of GDF15 (lg-GDF15), the risk of overall complications increased by 1.17-fold (95% confidence interval [CI], 1.03 to 1.32). In contrast to macrovascular complications, associations of GDF15 with microvascular complications appeared to be stronger (adjusted odds ratio [OR], 1.24; 95% CI, 1.08 to 1.43), especially for DKD (adjusted OR, 1.51; 95% CI, 1.19 to 1.93). Subgroup analyses showed that the strength of association between GDF15 and complications varied by distinct age and T2DM duration subgroups. Patients with 2 or more types of complications had higher levels of GDF15 than those with fewer types of complications. Also, linear relationships were identified between GDF15 and several liver and kidney function indices.

CONCLUSION

Higher GDF15 levels were associated with T2DM complications, especially DKD. GDF15 may serve as a biomarker for monitoring the deterioration of T2DM.

Significant increase of serum extracellular vesicle-packaged growth differentiation factor 15 in type 2 diabetes mellitus: a cross-sectional study

BACKGROUND

Growth differentiation factor 15 (GDF15) is a stress-inducible factor involved in the inflammatory progression of many complications, including type 2 diabetes mellitus (T2DM). Growing evidence suggests that molecules in extracellular vesicles (EVs) are associated with diabetes or diabetes-related complications. However, the correlation between serum extracellular vesicle-derived growth differentiation factor15 (EV-GDF15) and T2DM is unknown. The aim of this cross-sectional study is to investigate whether serum EV-GDF15 is associated with T2DM incidence.

METHODS

116 individuals, including 78 T2DM and 38 non-T2DM, were recruited as participants. The concentrations of serum EV-GDF15 and serum GDF15 were determined by Luminex assay. Serum EVs were obtained by ultracentrifugation. Multivariate stepwise regression analysis was used to determine the association between serum GDF15 levels and fasting plasma glucose (FPG) as well as glycated hemoglobin (HbA1c). The association of serum EV-GDF15 levels with T2DM was determined by multivariate logistic regression analysis.

RESULTS

Our data showed that the levels of serum EV-GDF15 and serum GDF15 were significantly increased in T2DM patients compared with non-T2DM subjects (EV-GDF15 levels, 13.68 (6.61-23.44) pg/mL vs. 5.56 (3.44-12.09) pg/mL, P < 0.001; and serum GDF15 levels, 1025.49 (677.87-1626.36) pg/mL vs. 675.46 (469.53-919.98) pg/mL, P < 0.001). There was a linear correlation between EV-GDF15 levels and fasting plasma glucose (FPG) and Hemoglobin A1C (HbA1c) levels (normalized β = 0.357, P < 0.001; normalized β = 0.409, P < 0.001, respectively). Elevated levels of EV-GDF15 were accompanied by an increase in the proportion of patients with T2DM (from 47.5 to 78.9%) and a progressive independent association with the incidence of T2DM (from OR = 3.06, 95% CI 1.02-9.19, P = 0.047 to OR = 3.75, 95% CI 1.14-12.26, P = 0.029). Notably, high levels of serum GDF15 plus high levels of serum EV-GDF15 were significantly associated with T2DM more than either alone.

CONCLUSION

This study elucidated that increased levels of GDF15 in serum EVs were independently associated with T2DM.

Growth differentiation factor-15 is independently associated with metabolic syndrome and hyperglycemia in non-elderly subjects

Metabolic syndrome (MetS) is a major health issue worldwide accompanied by cardiovascular comorbidities. Growth differentiation factor-15 (GDF-15) is a stress-responsive cytokine expressed in cardiomyocytes, adipocytes, macrophages, and endothelial cells. Previous research in elderly subjects revealed that GDF-15 levels were associated with the MetS. However, the association between GDF-15 levels and MetS or its components in the non-elderly subjects remains unclear. In this study, a total of 279 subjects younger than 65-year-old with (n = 84) or without (n = 195) MetS were recruited. MetS was defined according to modified NCEP/ATP III criteria. The GDF-15 levels were measured by an enzyme-linked immunosorbent assay. A multiple linear regression analysis was conducted to identify factors independently associated with GDF-15 levels. Subjects with MetS had higher GDF-15 levels than those without MetS (median (interquartile range), 1.72 ng/mL (1.38, 2.26) vs. 1.63 ng/mL (1.27, 2.07), P = 0.037). With the number of MetS components increased, the GDF-15 levels increased significantly (P for trend = 0.005). Multiple linear regression analysis revealed that the presence of MetS was positively associated with the GDF-15 levels (β = 0.132, P = 0.037). When substituting MetS with its components, only the presence of hyperglycemia was positively associated with the GDF-15 levels after adjustment for covariates (β = 0.193, P = 0.003). Taken together, the presence of the MetS in non-elderly was associated with higher GDF-15 levels. Among the MetS components, only hyperglycemia was significantly associated with the GDF-15 levels. Future longitudinal studies will be needed to explore whether GDF-15 has the potential to be a biomarker of gluco-metabolic dysfunction in non-elderly subjects.

Association between growth differentiation factor 15 levels and gestational diabetes mellitus: A combined analysis

OBJECTIVE

Gestational diabetes mellitus (GDM) is a common glucose metabolism disease occurs in pregnancy that affects both maternal and neonatal health. Recently, increasing studies have attached importance to the relationship between growth differentiation factor 15 (GDF-15) and GDM, but the results were inconclusive. Therefore, we conducted a meta-analysis to examine the association between GDF-15 and GDM.

MATERIALS AND METHODS

A systematical search was performed in Gene Expression Omnibus (GEO), PubMed and Google Scholar till Oct 27, 2022. We first calculated the mean and standard deviation of GDF-15 expression levels from the included eligible datasets and articles. Then, a meta-analysis was conducted to depict the difference in GDF-15 mRNA or GDF-15 protein expression between case and control groups by using conservative random effect model. Moreover, the potential publication bias was checked with the aid of Begg's test and Egger's test. Finally, sensitivity analyses were performed by changing the inclusion criteria.

RESULTS

In summary, 12 GEO datasets and 5 articles were enrolled in our study, including 789 GDM patients and 1202 non-GDM pregnant women. It was found that the expression levels of GDF-15 mRNA and GDF-15 protein in late pregnancy were significantly higher in GDM patients compared with non-GDM pregnant women, with the standard mean difference (SMD) and 95% confidence interval (95% CI) of 0.48 (0.14, 0.83) and 0.82 (0.32-1.33), respectively. Meanwhile, a slightly weakened association between GDF-15 protein levels and GDM was also observed in the middle pregnancy, with SMD (95% CI) of 0.53 (0.04-1.02).

CONCLUSION

In all, our results suggested that the expression levels of GDF-15 were significantly higher in GDM patients compared with non-GDM pregnant women, especially in the late pregnancy.

Serum growth differentiation factor-15 levels are associated with the severity of diabetic foot ulcer

AIMS

To assess serum growth differentiation factor-15 (GDF-15) levels in patients with diabetic foot ulcer and to reveal whether any association exists between GDF-15 and the severity of diabetic foot ulcer.

DESIGN

A cross-sectional study including three age- and sex-matched cohorts comprising 17 patients (7 F, mean age: 52 ± 7 years) with diabetic foot ulcer (DMf), 17 patients with type 2 diabetes (6 F, mean age: 51 ± 6 years) with no foot complication (DM), and 20 healthy controls (8 F, mean age: 50 ± 8 years) (C) was conducted.

RESULTS

DMf had higher GDF-15 levels, followed by DM and C (GDF-15, median ± IQR (pg/mL), DMf: 1039 (884-1566), DM: 649 (375-1148), and C: 296 (212-534), p < 0.001). The severity of diabetic foot disease was positively associated with serum GDF-15 (GDF-15, median ± IQR (pg/mL), Wagner grade 1: 893 (698-1039), Wagner grade 3: 1705 (1348-2197), and Wagner grade 4: 3075 (1974-4176), p for trend = 0.006). In multivariate regression model, only Wagner grade (β = 0.55, 95% CI (87-753), p = 0.02) was found to be an independent factor affecting serum GDF-15 concentration.

CONCLUSIONS

Serum GDF-15 levels are high in patients with diabetic foot ulcer. The level is higher in more advanced lesions. GDF-15 measurement can have clinical utility in the management of diabetic foot ulcers.

Serum CD14 concentration is associated with obesity and insulin resistance in non-diabetic individuals

OBJECTIVE

CD14 is a lipopolysaccharide-binding protein that serves as a marker of monocytes. The role of circulating CD14 in patients with obesity without diabetes remains unknown. Here, we characterized the relationships between serum CD14 concentration and metabolic parameters related to diabetes and obesity.

METHODS

We performed an observational, prospective case-control study. Eighty participants were evaluated: 26 drug-naïve patients with type 2 diabetes mellitus and 54 healthy individuals. We compared the circulating CD14 concentration and metabolic parameters of the participants with and without diabetes.

RESULTS

The circulating CD14 concentration did not significantly differ between the two groups, but was lower in participants with obesity than in lean controls. No significant associations existed between CD14 concentration and metabolic parameters in the participants with diabetes, but in those without diabetes, the circulating CD14 concentration significantly negatively correlated with body mass index; waist circumference; the concentrations of fasting insulin, 2-hour post-load glucose, 2-h post-load insulin, and low-density lipoprotein-cholesterol; homeostasis model of assessment (HOMA) of insulin resistance; and HOMA beta-cell function.

CONCLUSIONS

This is the first study to show associations of serum CD14 concentration with metabolic parameters in non-diabetic individuals. Circulating CD14 may represent a useful biomarker of metabolic dysfunction in non-diabetic individuals.

Pro-tumorigenic role of type 2 diabetes-induced cellular senescence in colorectal cancer

Colorectal cancer (CRC) is the second leading cause of cancer-related mortality worldwide. The disease still remains incurable and highly lethal in the advanced stage, representing a global health concern. Therefore, it is essential to understand the causes and risk factors leading to its development. Because age-related cellular senescence and type 2 diabetes (T2D) have been recognised as risk factors for CRC development, the recent finding that type 2 diabetic patients present an elevated circulating volume of senescent cells raises the question whether type 2 diabetes facilitates the process of CRC tumorigenesis by inducing premature cell senescence. In this review, we will discuss the mechanisms according to which T2D induces cellular senescence and the role of type 2 diabetes-induced cellular senescence in the pathogenesis and progression of colorectal cancer. Lastly, we will explore the current therapeutic approaches and challenges in targeting senescence.

Major Adverse Cardiovascular Events and Mortality Prediction by Circulating GDF-15 in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis

Background: Growth differentiation factor 15 (GDF-15) is a homeostatic cytokine that regulates neural and cardio-metabolic functions, and its release is increased in response to stress, injury, and inflammation. In patients with coronary artery disease and heart failure (HF), three separate meta-analyses have found that elevated circulating GDF-15 was predictive of major adverse cardiovascular events (MACE), but none has evaluated its effects on incident MACE including HF and mortality hazard in type 2 diabetes. Methods: MEDLINE, EMBASE, and Scopus databases were queried. Articles that met the predefined eligibility criteria, including prospective studies that reported adjusted hazard ratios (aHRs), were selected according to the Cochrane Handbook and PRISMA guidelines. Study endpoints were (1) MACE including HF, and (2) all-cause mortality. Different GDF-15 concentration measurements were harmonized using a validated mathematical approach to express log2-transformed values in per standard deviation (SD). Study heterogeneity (I2), quality, and bias were assessed. Results: 19354 patients in 8 prospective studies were included. In 7 studies that reported 4247 MACE among 19200 participants, the incident rate was 22.1% during a median follow-up of 5.6 years. It was found that four of eight studies included HF decompensation or hospitalization as a component of MACE. In 5 studies that reported all-cause mortality, 1893 of 13223 patients died, at an incidence rate of 15.1% over 5.0 years. Of note, each 1 SD increase of log2[GDF-15] was associated with aHRs of 1.12 (1.09−1.15, I2 = 5%, p < 0.000001) and 1.27 (1.11−1.46, I2 = 86%, p = 0.00062) and for MACE and all-cause mortality, respectively. Conclusion: Elevated circulating level of GDF-15 was robustly predictive of MACE in patients with T2D but its prognostic significance in the prediction of mortality requires further studies.

Biomarkers of subclinical atherosclerosis in patients with psoriasis

Psoriasis is linked with increased risk of cardiovascular disease (CVD) that is underestimated by traditional risk stratification. We conducted a large-scale plasma proteomic analysis by use of a proximity extension assay in 85 patients with a history of moderate-to-severe psoriasis with or without established atherosclerotic CVD. Differentially expressed proteins associated with CVD were correlated with subclinical atherosclerotic markers including vascular inflammation determined by 18F-fluorodeoxyglucose positron emission tomography/computed tomography, carotid intima-media thickness (CIMT), carotid artery plaques, and coronary artery calcium score (CCS) in the patients without CVD and statin treatment. We also examined the association between the neutrophil-to-lymphocyte ratio (NLR) and subclinical atherosclerosis. In unadjusted analyses, growth differentiation factor-15 (GDF-15) levels and NLR were increased, while tumor necrosis factor (TNF)-related activation-inducing ligand (TRANCE) and TNF-related apoptosis-induced ligand (TRAIL) levels were decreased in patients with established CVD compared to those without CVD. Among patients with psoriasis without CVD and statin treatment, GDF-15 levels were negatively associated with vascular inflammation in the ascending aorta and entire aorta, and positively associated with CIMT and CCS. NLR was positively associated with vascular inflammation in the carotid arteries. Our data suggest that circulating GDF-15 levels and NLR might serve as biomarkers of subclinical atherosclerosis in patients with psoriasis.

Growth Differentiation Factor 15 is Related with Left Ventricular Recovery in Patients with ST-Elevation Myocardial Infarction after Successful Reperfusion by Primary Percutaneous Intervention

Background

The determinants of left ventricular (LV) recovery after successful revascularization in ST-elevation myocardial infarction (STEMI) patients are not clear. In addition, the relationship between growth differentiation factor15 (GDF-15) and left ventricular ejection fraction (LVEF) improvement is also unknown. This study hypothesizes that a low GDF-15 level would be associated with LVEF recovery.

Methods

One hundred and sixty-one STEMI patients were included in this study. Echocardiographic examinations were performed before and 12-18 weeks after discharge. The patients were divided into three groups according to the changes in LVEF as 62 patients with ≥ 10% change, 47 patients with 1-9% change, and 52 patients ≤ 0% change. LV recovery was defined as ≥ 10% LVEF improvement and the predictors of LV recovery were investigated. Moreover, two groups were created according to GDF-15 values, and the follow-up/baseline echocardiographic parameters were compared between these groups.

Results

LV recovery was detected in 38.5% of the patients. Low baseline LVEF [odds ratio (OR): 0.85, 95% confidence interval (CI) 0.82-0.94, p = 0.001], low GDF-15 (OR: 0.79, 95% CI 0.68-0.93, p = 0.004), previous angina (OR: 2.34, 95% CI 1.10-4.96, p = 0.027), and symptom-to-balloon time (OR: 0.97, 95% CI 0.95-1.00, p = 0.043) were independent predictors of LV recovery. The ratios of follow-up/baseline LV end-diastolic volume index, LV end-systolic volume index and wall motion score index were lower in the low GDF-15 group (0.96 vs. 1.04, p < 0.001; 0.96 vs. 1.10, p < 0.001; 0.89 vs. 0.96, p < 0.001). Moreover, being in the low GDF-15 group was associated with LV recovery (OR: 2.93, 95% CI 1.43-6.02, p = 0.001).

Conclusions

Lower GDF-15 level was associated with better LV improvement and less adverse remodeling in STEMI patients.

The diagnostic value of GDF-15 for myocardial involvement in idiopathic inflammatory myopathy

BACKGROUND

Cardiac involvement is a serious complication of idiopathic inflammatory myopathy (IIM). GDF-15 can predict the risk and the prognosis of cardiovascular disease, but its value is unclear in IIM.

OBJECTIVE

To investigate the diagnostic value of GDF-15 for myocardial involvement in IIM.

METHODS

A total of 77 IIM patients from May 2018 to August 2020 were included in this retrospective study. Of these, 43 patients underwent cardiac magnetic resonance (CMR) examination. There were 33 SLE patients and 16 healthy people were used as the control group. The concentration of GDF-15 of these groups was measured by ELISA.

RESULTS

There were significant differences in GDF-15 levels in patients with IIM, SLE and healthy controls (H = 45.291, P<0.001). GDF-15 levels were statistically significant different between IIM patients with the myocardial injury [1484.88(809.07 2835.50) pg/ml] and without myocardial injury [593.26(418.61 784.59) pg/ml, P =0.001]. After adjusted for age, renal function, the risk of myocardial injury in IIM patients increased an average of 0.3% by per increased unit of GDF-15 (odds ratio=1.003, 95% CI: 1.000, 1.007). The level of GDF-15 was positively correlated with extra-cellular volume (ECV) (rs = 0.348, P =0.028). GDF-15 ≥ 929.505 pg/ml (area under the curve=0.856, 95% CI: 0.744, 0.968) predicted myocardial injury in IIM with a sensitivity of 0.75 and specificity of 0.90.

CONCLUSION

GDF-15 could serve as a potential biomarker to predict myocardial injury in IIM patients.

Associations of GDF-15 and GDF-15/adiponectin ratio with odds of type 2 diabetes in the Chinese population

PURPOSE

We elucidate the effect of Growth differentiation factor-15(GDF-15)/adiponectin ratio in improving the assessment value for odds of type 2 diabetes.

METHODS

Cross-sectional design. A total of 405 participants (135 patients with newly diagnosed type 2 diabetes, 135 age- and sex-matched participants with prediabetes, and 135 healthy controls) were collected from Guangzhou and Dongguan, China. The serum GDF-15 and adiponectin levels were measured by ELISA and latex-enhanced immunoturbidimetry. Logistic regression analysis and restricted cubic splines were used to evaluate the associations between diabetes and the indicators.

RESULTS

The low level of adiponectin and high GDF-15/adiponectin ratio were significantly associated with increased odds of type 2 diabetes, but not for GDF-15. Three clusters were identified based on the K-means clustering analysis. Compared to the lowest quartiles of adiponectin, the OR and 95% CI of the highest adiponectin with type 2 diabetes was 0.24 (0.07-0.74, p trend = 0.004) after adjusting for sex, age, BMI, and DBP only in cluster 1. After adjusting for confounding factors, subjects with the highest GDF-15/adiponectin ratio quartiles had 3.9 times (OR = 3.85, 95% CI = 0.76-24.25) and 3.8 times (OR = 3.80, 95% CI = 1.02-14.68) higher odds of type 2 diabetes in cluster 2 and cluster 3, respectively. The association between the GDF-15/adiponectin ratio and type 2 diabetes was attenuated, but still remarkable (OR = 3.18, 95% CI = 1.11-10.18), in cluster 1.

CONCLUSIONS

Higher GDF-15/adiponectin ratio is independently associated with increased odds of type 2 diabetes for all study populations, suggesting that the GDF-15/adiponectin ratio may be a better indicator of type 2 diabetes.

Growth Differentiation Factor 15 is a Cancer Cell-Induced Mitokine That Primes Thyroid Cancer Cells for Invasiveness

Background: Mitochondrial stress is known to activate the mitochondrial unfolded protein response (UPR^mt). The UPR^mt results in the secretion of mitochondrial cytokines (mitokines), which can promote a hormetic response cell nonautonomously, and has been reported to be protumorigenic. Growth differentiation factor 15 (GDF15) is a well-characterized mitokine, which is reported to have a mitohormetic effect. Thus, we investigated whether GDF15 induction could prime a subpopulation of thyroid cancer cells to provide invasive advantages. Methods: The UPR^mt, including mitokine expression, was assessed in the context of thyroid cancer in vitro and in vivo. GDF15 expression in 266 patients with papillary thyroid carcinoma (PTC) was determined by immunohistochemistry. The serum levels of GDF15 were measured in healthy subjects and PTC patients. In addition, our own and The Cancer Genome Atlas data were analyzed to determine the expression level of GDF15 in thyroid cancers. The role of GDF15 in tumor aggressiveness was investigated by observing the effects of GDF15 knockdown in BCPAP, TPC-1, 8505C, and FRO cells. Results: Pharmacological inhibition of mitochondrial oxidative phosphorylation function in thyroid cancer cells robustly increased GDF15 expression. The expression of GDF15 was associated with activation of the mitochondrial integrated stress response pathway in PTC patients. Circulating GDF15 levels were significantly higher in PTC patients than in the controls, and tumor expression of GDF15 was related to tumor aggressiveness. In vitro and in vivo knockdown of GDF15 in a thyroid cancer model showed decreased viability, migration, and invasion compared with the control cells via regulation of STAT3. Conclusions: In this study, we demonstrated that GDF15 is a mitokine induced in thyroid cancer cells upon mitochondrial stress. GDF15-induced STAT3 activation determined tumor progression in thyroid cancer. The GDF15-STAT3 signaling axis may be a target in aggressiveness of thyroid cancer.

Changes in plasma sclerostin level associated with use of a medium cut-off dialyzer in end-stage renal disease

Background

Larger middle molecules are important substances associated with cardiovascular complications in end- stage renal disease. Unfortunately, larger middle molecules are not reliably removed by a high -flux dialyzer. A medium cut-off (MCO) membrane could effectively remove larger middle molecules. This study aimed to identify the long-term effect of the MCO membrane for changes of larger middle molecules.

Methods

Thirty-four patients were prospectively analyzed for 12 months. The enrolled patients were divided into control and MCO groups. We measured the plasma levels of growth differentiation factor 15, sclerostin, and fibroblast growth factor 23 in larger middle molecules and those of biomarkers including small solutes. Single-pool Kt/V (spKt/V) and reduction ratios also were evaluated.

Results

Plasma sclerostin did not increase significantly in patients using the MCO dialyzer (135.294 [–637.726 to 908.314], p = 0.715). And there was a significant difference in change of plasma sclerostin level between the two groups (–1,646.916 [–3,015.150 to –278.682], p = 0.033). Furthermore, a negative association between calcium and sclerostin was not observed in the MCO group (r = –0.142, p = 0.587). Solute clearance of larger middle molecules in the MCO group was significantly higher. Moreover, spKt/V values for patients in the MCO group were significantly increased without albumin loss. Values are presented as mean (95% confidence interval [CI]) or adjusted mean (95% CI).

Conclusion

The MCO dialyzer can increase dialytic adequacy and suppress the increase in plasma sclerostin level without significant albumin loss in patients with end-stage renal disease.

Identification of potential lncRNAs and co-expressed mRNAs in gestational diabetes mellitus by RNA sequencing

AIM

Gestational diabetes mellitus is common during pregnancy, impacting maternal health and fetal development. The aim of this study was to identify potential long non-coding RNAs (lncRNAs) and mRNAs in gestational diabetes mellitus.

METHODS

The placenta tissues from four women patients with gestational diabetes mellitus and three healthy pregnant women were used for RNA sequencing. Differentially expressed lncRNAs and mRNAs were obtained. Then, interaction networks of lncRNA-nearby targeted mRNA and lncRNA-co-expressed mRNA were constructed, followed by functional annotation of co-expressed mRNAs. Third, GSE51546 dataset was utilized to validate the expression of selected co-expressed mRNAs. In addition, in vitro experiment was applied to expression validation of lncRNAs and mRNAs. Finally, GSE70493 dataset was utilized for diagnostic analysis of selected co-expressed mRNAs.

RESULTS

A total of 78 differentially expressed lncRNAs and 647 differentially expressed mRNAs in gestational diabetes mellitus were obtained. Several interaction pairs of lncRNA-co-expressed mRNA including LINC01504-CASP8, FUT8-AS1-TLR5/GDF15, GATA2-AS1-PQLC3/KIAA2026, and EGFR-AS1-HLA-G were identified. Endocytosis (involved HLA-G) and toll-like receptor signaling pathway (involved TLR5 and CASP8) were remarkably enriched signaling pathways of co-expressed mRNAs. It is noted that CASP8, TLR5, and PQLC3 had a significant prognosis value for gestational diabetes mellitus.

CONCLUSIONS

Our study identified several differentially expressed lncRNAs and mRNAs, and their interactions, especially co-expression, may be associated with gestational diabetes mellitus.

Relationship between plasma growth differentiation factor-15 levels and diabetic retinopathy in individuals with type 2 diabetes

The purpose of our study was to investigate the relationship between plasma growth differentiation factor-15 (GDF-15) concentrations and diabetic retinopathy in patients with type 2 diabetes mellitus (DM). We evaluated 235 patients with type 2 DM in a cross-sectional study. Significantly increased levels of the plasma GDF-15 were found in individuals with diabetic retinopathy versus those without. According to the degree of diabetic retinopathy, there was a significant difference in the average plasma GDF-15 levels (no diabetic retinopathy, 1114 ng/L; nonproliferative diabetic retinopathy, 1327 ng/L; proliferative diabetic retinopathy, 1445 ng/L; p for trend = 0.035) after adjustments for confounders. Logistic regression analyses indicated that plasma GDF-15 concentrations were significantly associated with diabetic retinopathy (odds ratio per 1 standard deviation increment in the log-transformed value, 1.78; 95% confidence interval, 1.05-3.03, p = 0.032). Our study showed a significant positive relationship between plasma GDF-15 concentrations and diabetic retinopathy in type 2 DM patients.

The GDF15-GFRAL Pathway in Health and Metabolic Disease: Friend or Foe?

GDF15 is a cell activation and stress response cytokine of the glial cell line-derived neurotrophic factor family within the TGF-β superfamily. It acts through a recently identified orphan member of the GFRα family called GFRAL and signals through the Ret coreceptor. Cell stress and disease lead to elevated GDF15 serum levels, causing anorexia, weight loss, and alterations to metabolism, largely by actions on regions of the hindbrain. These changes restore homeostasis and, in the case of obesity, cause a reduction in adiposity. In some diseases, such as advanced cancer, serum GDF15 levels can rise by as much as 10-100-fold, leading to an anorexia-cachexia syndrome, which is often fatal. This review discusses how GDF15 regulates appetite and metabolism, the role it plays in resistance to obesity, and how this impacts diseases such as diabetes, nonalcoholic fatty liver disease, and anorexia-cachexia syndrome. It also discusses potential therapeutic applications of targeting the GDF15-GFRAL pathway and lastly suggests some potential unifying hypotheses for its biological role.

Serum GDF15, a Promising Biomarker in Obese Patients Undergoing Heart Surgery

Background: Obesity is a risk factor that negatively impacts outcomes in patients undergoing heart surgery by mechanisms that are not well-defined nor predicated on BMI alone. This knowledge gap has fuelled a search for biomarkers associated with cardiovascular diseases that could provide clinical insight to surgeons. One such biomarker is growth differentiation factor15(GDF15), associated with inflammation, metabolism, and heart failure outcomes but not yet examined in the context of obesity and cardiac surgery outcomes.

Methods: Patients undergoing open-heart surgery were consented and enrolled for blood and tissue (atria) sampling at the time of surgery. Biomarker analysis was carried out using ELISA and western blot/qPCR, respectively. Biomarker screening was classified by inflammation(NLR, GDF15, Galectin3, ST2, TNFR2), heart failure(HF)/remodeling(NT-proBNP) and metabolism(glycemia, lipid profile). Patients were categorized based on BMI: obese group (BMI ≥30.0) and non-obese group(BMI 20.0–29.9). Subsequent stratification of GDF15 high patients was conservatively set as being in the 75th percentile.

Results: A total of 80 patients undergoing any open-heart surgical interventions were included in the study. Obese (mean BMI = 35.8, n = 38) and non-obese (mean BMI = 25.7, n = 42) groups had no significant differences in age, sex, or co-morbidities. Compared to other biomarkers, plasma GDF15 (mean 1,736 vs. 1,207 ng/l, p < 0.001) was significantly higher in obese patients compared to non-obese. Plasma GDF15 also displayed a significant linear correlation with BMI (R² = 0.097; p = 0.0049). Atria tissue was shown to be a significant source of GDF15 protein and tissue levels significantly correlated with plasma GDF15 (R² = 0.4, p = 0.0004). Obesity was not associated with early/late mortality at median follow-up >2years. However, patients with high GDF15 (>1,580 ng/l) had reduced survival (65%) compared to the remaining patients with lower GDF15 levels (95%) by Kaplan Meier Analysis (median >2 years; p = 0.007).

Conclusions: Circulating GDF15 is a salient biomarker likely sourced from heart tissue that appears to predict higher risk obese patients for adverse outcomes. More importantly, elevated GDF15 accounted for more sensitive outcome association than BMI at 2 years post-cardiac surgery, suggesting it heralds links to pathogenicity and should be actively studied prospectively and dynamically in a post-operative follow-up.

Trial number: NCT03248921.

Circulating Cardiac Biomarkers in Diabetes Mellitus: A New Dawn for Risk Stratification-A Narrative Review

The aim of this narrative review is to update the current knowledge on the differential choice of circulating cardiac biomarkers in patients with prediabetes and established type 2 diabetes mellitus (T2DM). There are numerous circulating biomarkers with unconfirmed abilities to predict clinical outcomes in pre-DM and DM individuals; the prognostication ability of the cardiac biomarkers reported here has been established, and they are still being studied. The conventional cardiac biomarkers, such as natriuretic peptides (NPs), soluble suppressor tumorigenisity-2, high-sensitivity circulating cardiac troponins and galectin-3, were useful to ascertain cardiovascular (CV) risk. Each cardiac biomarker has its strengths and weaknesses that affect the price of usage, specificity, sensitivity, predictive value and superiority in face-to-face comparisons. Additionally, there have been confusing reports regarding their abilities to be predictably relevant among patients without known CV disease. The large spectrum of promising cardiac biomarkers (growth/differential factor-15, heart-type fatty acid-binding protein, cardiotrophin-1, carboxy-terminal telopeptide of collagen type 1, apelin and non-coding RNAs) is discussed in the context of predicting CV diseases and events in patients with known prediabetes and T2DM. Various reasons have been critically discussed related to the variable findings regarding biomarker-based prediction of CV risk among patients with metabolic disease. It was found that NPs and hs-cTnT are still the most important tools that have an affordable price as well as high sensitivity and specificity to predict clinical outcomes among patients with pre-DM and DM in routine clinical practice, but other circulating biomarkers need to be carefully investigated in large trials in the future.

GDF15 Plasma Level Is Inversely Associated With Level of Physical Activity and Correlates With Markers of Inflammation and Muscle Weakness

Growth differentiation factor 15 (GDF15) is a stress molecule produced in response to mitochondrial, metabolic and inflammatory stress with a number of beneficial effects on metabolism. However, at the level of skeletal muscle it is still unclear whether GDF15 is beneficial or detrimental. The aim of the study was to analyse the levels of circulating GDF15 in people of different age, characterized by different level of physical activity and to seek for correlation with hematological parameters related to inflammation. The plasma concentration of GDF15 was determined in a total of 228 subjects in the age range from 18 to 83 years. These subjects were recruited and divided into three different groups based on the level of physical activity: inactive patients with lower limb mobility impairment, active subjects represented by amateur endurance cyclists, and healthy controls taken from the general population. Cyclists were sampled before and after a strenuous physical bout (long distance cycling race). The plasma levels of GDF15 increase with age and are inversely associated with active lifestyle. In particular, at any age, circulating GDF15 is significantly higher in inactive patients and significantly lower in active people, such as cyclists before the race, with respect to control subjects. However, the strenuous physical exercise causes in cyclists a dramatic increase of GDF15 plasma levels, that after the race are similar to that of patients. Moreover, GDF15 plasma levels significantly correlate with quadriceps torque in patients and with the number of total leukocytes, neutrophils and lymphocytes in both cyclists (before and after race) and patients. Taken together, our data indicate that GDF15 is associated with decreased muscle performance and increased inflammation.

The association between serum growth differentiation factor 15 levels and lower extremity atherosclerotic disease is independent of body mass index in type 2 diabetes

BACKGROUND

Clinical and basic investigations have indicated a significant association between circulating growth differentiation factor 15 (GDF15) and cardiovascular disease; however, the relationship between GDF15 and lower extremity atherosclerotic disease (LEAD) has been less studied. The present study aimed to explore the association between GDF15 and LEAD in Chinese patients with type 2 diabetes mellitus (T2DM). Considering that obesity is an important factor associated with circulating GDF15 levels, whether the relationship between serum GDF15 levels and LEAD is affected by body mass index (BMI) was also analysed.

METHODS

A total of 376 hospitalized T2DM patients were enrolled (161 with LEAD and 215 without LEAD). A sandwich enzyme-linked immunosorbent assay was used to detect the serum GDF15 levels. The femoral intima-media thickness (F-IMT) and LEAD were assessed by ultrasonography.

RESULTS

Patients with LEAD had significantly higher serum GDF15 levels than those without LEAD, regardless of whether their BMI was < 25 kg/m² or ≥ 25 kg/m² (both P < 0.05). Serum GDF15 levels were independently positively related to the F-IMT (standardized β = 0.162, P = 0.002). After adjusting for confounding factors, per 1-standard deviation (SD) increase in the serum GDF15 levels was significantly related to an approximately 1.4-fold increased risk of LEAD in the total population (P < 0.05). Regardless of whether the BMI was < 25 kg/m² or ≥ 25 kg/m², this association remained significant, with approximately 1.6- and 1.4-fold increased risks of LEAD, respectively (both P < 0.05).

CONCLUSIONS

High serum GDF15 levels were significantly correlated with an increased risk of LEAD in T2DM patients, and this relationship was independent of BMI.

Growth differentiation factor 15 (GDF-15) is a potential biomarker of both diabetic kidney disease and future cardiovascular events in cohorts of individuals with type 2 diabetes: a proteomics approach

Background: Diabetic kidney disease (DKD) is a leading risk factor for end-stage renal disease and is one of the most important risk factors for cardiovascular disease in patients with diabetes. It is possible that novel markers portraying the pathophysiological underpinning processes may be useful.Aim: To investigate the associations between 80 circulating proteins, measured by a proximity extension assay, and prevalent DKD and major adverse cardiovascular events (MACE) in type 2 diabetes.Methods: We randomly divided individuals with type 2 diabetes from three cohorts into a two-thirds discovery and one-third replication set (total n = 813, of whom 231 had DKD defined by estimated glomerular filtration rate <60 mg/mL/1.73 m² and/or urinary albumin-creatinine ratio ≥3 g/mol). Proteins associated with DKD were also assessed as predictors for incident major adverse cardiovascular events (MACE) in persons with DKD at baseline.Results: Four proteins were positively associated with DKD in models adjusted for age, sex, cardiovascular risk factors, glucose control, and diabetes medication: kidney injury molecule-1 (KIM-1, odds ratio [OR] per standard deviation increment, 1.65, 95% confidence interval [CI] 1.27-2.14); growth differentiation factor 15 (GDF-15, OR 1.40, 95% CI 1.16-1.69); myoglobin (OR 1.57, 95% CI 1.30-1.91), and matrix metalloproteinase 10 (MMP-10, OR 1.43, 95% CI 1.17-1.74). In patients with DKD, GDF-15 was significantly associated with increased risk of MACE after adjustments for baseline age, sex, microalbuminuria, and kidney function and (59 MACE events during 7 years follow-up, hazard ratio per standard deviation increase 1.43 [95% CI 1.03-1.98]) but not after further adjustments for cardiovascular risk factors.Conclusion: Our proteomics approach confirms and extends previous associations of higher circulating levels of GDF-15 with both micro- and macrovascular disease in patients with type 2 diabetes. Our data encourage additional studies evaluating the clinical utility of our findings.

Quantitative Proteomics Evaluation of Human Multipotent Stromal Cell for β Cell Regeneration

Human multipotent stromal cells (hMSCs) are one of the most versatile cell types used in regenerative medicine due to their ability to respond to injury. In the context of diabetes, it has been previously shown that the regenerative capacity of hMSCs is donor specific after transplantation into streptozotocin (STZ)-treated immunodeficient mice. However, in vivo transplantation models to determine regenerative potency of hMSCs are lengthy, costly, and low throughput. Therefore, a high-throughput quantitative proteomics assay was developed to screen β cell regenerative potency of donor-derived hMSC lines. Using proteomics, we identified 16 proteins within hMSC conditioned media that effectively identify β cell regenerative hMSCs. This protein signature was validated using human islet culture assay, ELISA, and the potency was confirmed by recovery of hyperglycemia in STZ-treated mice. Herein, we demonstrated that quantitative proteomics can determine sample-specific protein signatures that can be used to classify previously uncharacterized hMSC lines for β cell regenerative clinical applications.

Association between MIC-1 and Type 2 Diabetes: A Combined Analysis

Background and Objectives

Type 2 diabetes mellitus (T2DM) is an epidemic disease that endangers human health seriously. Recently, a large number of reports have revealed that macrophage-inhibiting cytokine-1 (MIC-1) is linked with T2DM, but the results were inconclusive. The aim of this study was to perform bioinformatics analysis of the association between MIC-1 and T2DM.

Material and Methods

Datasets and relevant literatures were searched in Gene Expression Omnibus (GEO), PubMed, Google Scholar, and Web of Science till September 20, 2019. Expression levels of MIC-1 were extracted, pooled, and compared between T2DM cases and controls.

Results

In summary, 11 GEO datasets and 3 articles with 421 T2DM cases and 711 controls were finally included. The expression level of MIC-1 was significantly higher in T2DM patients compared with controls, with a standard mean difference (SMD) of 0.54 and a 95% confidence interval (95% CI) of 0.24-0.83; in blood samples, the difference was still significant (SMD = 0.65; 95%CI = 0.24‐1.06). Meanwhile, the expression level of MIC-1 plays a significant role in differentiating T2DM cases from controls; the combined sensitivity, specificity, and odds ratio were 0.83 (95%CI = 0.72‐0.90), 0.59 (95%CI = 0.45‐0.72), and 1.64 (95%CI = 1.35‐1.99), respectively. The summary receiver operating characteristic (SROC) curve demonstrated that the area under the curve (AUC) was 0.81 (95%CI = 0.77‐0.84).

Conclusion

Our results suggested that the expression levels of MIC-1 were significantly higher in T2DM patients in multiple tissues including blood samples.

The clinical impact of growth differentiation factor-15 in heart disease: A 2019 update

Growth differentiation factor-15 (GDF-15), also known as macrophage inhibitory cytokine-1 (MIC-1) or non-steroidal anti-inflammatory drug-activated gene (NAG-1) has been identified as a biomarker of response to treatment and prognosis in cardiovascular diseases. GDF-15 is a member of the transforming growth factor-β superfamily and is involved in several pathological conditions such as inflammation, cancer, cardiovascular, pulmonary and renal diseases. Cardiac myocytes produce and secrete GDF-15 in response to oxidative stress, stimulation with angiotensin II or proinflammatory cytokines, ischemia, and mechanical stretch. Other cellular sources of GDF-15 production are macrophages, vascular smooth muscle cells, endothelial cells, and adipocytes, which secrete GDF-15 in response to oxidative or metabolic stress or stimulation of proinflammatory cytokines. GDF-15 is induced in hypertrophic and dilated cardiomyopathy after volume overload, ischemia, and heart failure. GDF-15 can be used as a marker of prognosis in patients with cardiovascular disorders, in combination with conventional prognostic factors, such as N-terminal pro B-type natriuretic peptide (NT-proBNP) and high-sensitivity troponin T (hs-TnT).

Regulation of Systemic Glucose Homeostasis by T Helper Type 2 Cytokines

Obesity results in an inflammatory microenvironment in adipose tissue, leading to the deterioration of tissue protective mechanisms. Although recent studies suggested the importance of type 2 immunity in an anti-inflammatory microenvironment in adipose tissue, the regulatory effects of T helper 2 (Th2) cytokines on systemic metabolic regulation are not fully understood. Recently, we identified the roles of the Th2 cytokine (interleukin 4 [IL-4] and IL-13)-induced adipokine, growth differentiation factor 15 (GDF15), in adipose tissue in regulating systemic glucose metabolism via signal transducer and activator of transcription 6 (STAT6) activation. Moreover, we showed that mitochondrial oxidative phosphorylation is required to maintain these macrophage-regulating autocrine and paracrine signaling pathways via Th2 cytokine-induced secretion of GDF15. In this review, we discuss how the type 2 immune response and Th2 cytokines regulate metabolism in adipose tissue. Specifically, we review the systemic regulatory roles of Th2 cytokines in metabolic disease and the role of mitochondria in maintenance of type 2 responses in adipose tissue homeostasis.

Serum R-Spondin 1 Is a New Surrogate Marker for Obesity and Insulin Resistance

BACKGROUND

Recent in vivo studies indicated that R-spondin 1 (RSPO1) regulates food intake and increases insulin secretion, but its role in humans remains unknown. This study investigated the association between serum levels of RSPO1 and diverse metabolic parameters in humans.

METHODS

The study population consisted of 43 subjects with newly diagnosed diabetes mellitus, and 79 non-diabetic participants. Serum levels of RSPO1 were measured using the enzyme-linked immunosorbent assay. The relationships between circulating RSPO1 and diverse metabolic parameters were analyzed.

RESULTS

Circulating RSPO1 levels increased to a greater extent in the obese group than in the lean group. Moreover, serum levels of RSPO1 were higher in the insulin-resistant group than in the insulin-sensitive group. Serum levels of RSPO1 were significantly correlated with a range of metabolic parameters including body mass index, fasting C-peptide, homeostasis model assessment of insulin resistance index, and lipid profile. Moreover, levels were significantly associated with insulin resistance and obesity in non-diabetic subjects.

CONCLUSION

This study demonstrated the association between serum levels of RSPO1 and a range of metabolic parameters in humans. Serum levels of RSPO1 are significantly related to obesity and insulin resistance, although the precise mechanisms remain unknown.

Effects of plant and animal high protein diets on immune-inflammatory biomarkers: A 6-week intervention trial

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).

Prognostication of clinical outcomes in diabetes mellitus: Emerging role of cardiac biomarkers

Type 2 diabetes mellitus (T2DM) remains substantial health problem and one of the most prevalent metabolic diseases worldwide. The impact of T2DM on CV mortality and morbidity is embedded through a nature evolution of the disease and is modulated by numerous risk factors, such as hypertension, obesity, dyslipidemia. There is large body of evidence regarding use of the cardiac biomarkers to risk stratification at higher CV risk individuals who belongs to general population and cohort with established CV disease. Although T2DM patients have higher incidence of cardiac and vascular complications than the general population, whether cardiac biomarkers would be effective to risk stratification of the T2DM is not fully understood. The aim of the review is to summarize our knowledge regarding clinical implementation of cardiac biomarkers in risk assessment for T2DM patients. The role of natriuretic peptides, soluble ST2, galectin-3, growth differentiation factor-15, and cardiac troponins are widely discussed.

The MIC-1/GDF15-GFRAL Pathway in Energy Homeostasis: Implications for Obesity, Cachexia, and Other Associated Diseases

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.

Growth differentiation factor-15 and fibroblast growth factor-23 are associated with mortality in type 2 diabetes - An observational follow-up study

Objectives

Two biomarkers, growth differentiation factor 15 (GDF-15) and fibroblast growth factor 23 (FGF-23)), reflecting different aspects of renal pathophysiology, were evaluated as determinants of decline in estimated glomerular filtration rate (eGFR), incident cardiovascular disease (CVD) and all-cause mortality in patients with type 2 diabetes (T2D) and microalbuminuria, but without clinical cardiac disease.

Materials and methods

Prospective study including 200 T2D patients. The predefined endpoint of chronic kidney disease (CKD) progression: A decline in eGFR of >30% at any time point during follow-up. Hazard ratios (HR) are provided per 1 SD increment of log2-transformed values.

Results

Mean (± SD) age was 59 ± 9 years, eGFR 91.1 ± 18.3 ml/min/1.73m² and median (IQR) UAER 103 (39–230) mg/24-h. During a median 6.1 years follow-up, 40 incident CVD events, 26 deaths and 42 patients reached the CKD endpoint after median 4.9 years. Higher GDF-15 was a determinant of decline in eGFR >30% and all-cause mortality in adjusted models (HR 1.7 (1.1–2.5); p = 0.018 and HR 1.9 (1.2–2.9); p = 0.003, respectively). Adding GDF-15 to traditional risk factors improved risk prediction of decline in renal function (relative integrated discrimination improvement (rIDI) = 30%; p = 0.037). Higher FGF-23 was associated with all-cause mortality in adjusted models (HR 1.6 (1.1–2.2); p = 0.011) with a rIDI of 30% (p = 0.024).

Conclusions

In patients with T2D and microalbuminuria, higher GDF-15 and FGF-23 were independently associated with all-cause mortality and higher GDF-15 improved risk prediction of decline in kidney function and higher FGF-23 of all-cause mortality, beyond traditional risk factors, but not independently of GDF-15.

Fasting exacerbates hepatic growth differentiation factor 15 to promote fatty acid β-oxidation and ketogenesis via activating XBP1 signaling in liver

Liver coordinates a series of metabolic adaptations to maintain systemic energy balance and provide adequate nutrients for critical organs, tissues and cells during starvation. However, the mediator(s) implicated in orchestrating these fasting-induced adaptive responses and the underlying molecular mechanisms are still obscure. Here we show that hepatic growth differentiation factor 15 (GDF15) is regulated by IRE1α-XBP1s branch and promotes hepatic fatty acids β-oxidation and ketogenesis upon fasting. GDF15 expression was exacerbated in liver of mice subjected to long-term fasted or ketogenic diet feeding. Abrogation of hepatic Gdf15 dramatically attenuated hepatic β-oxidation and ketogenesis in fasted mice or mice with STZ-initiated type I diabetes. Further study revealed that XBP1s activated Gdf15 transcription via binding to its promoter. Elevated GDF15 in liver reduced lipid accumulation and impaired NALFD development in obese mice through enhancing fatty acids oxidation in liver. Therefore, our results demonstrate a novel and critical role of hepatic GDF15 activated by IRE1α-XBP1s branch in regulating adaptive responses of liver upon starvation stress.

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GDF15 is augmented in livers of mice subjected to fasting or ketogenic diet feeding.

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XBP1s activates the transcription of Gdf15 via binding to its promoter.

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Abrogation of hepatic Gdf15 impairs fatty acid β-oxidation and ketogenesis.

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Inhibition of hepatic Gdf15 attenuates ketoacidosis of diabetic mice.

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Ectopic expression of hepatic GDF15 alleviates obese-induced NAFLD development.

The Role of Circulating Slit2, the One of the Newly Batokines, in Human Diabetes Mellitus

BACKGROUND

Slit2 is a new secreted protein from adipose tissue that improves glucose hemostasis in mice; however, there is no study about the serum levels and precise role of Slit2 in human. The aim of this study is to explore the serum level of Slit2 in human, and to identify the role of Slit2 in diabetes mellitus (DM).

METHODS

The participants of this study consist of 38 subjects with newly diagnosed DM, and 75 healthy subjects as a control group. Serum Slit2 levels were measured using an enzyme-linked immunosorbent assay. Relationship between circulating Slit2 and diabetic related factors was investigated in diabetic group compared with non-diabetic group. Additionally, the correlations between the serum level of Slit2 and diverse metabolic parameters were analyzed.

RESULTS

Circulating Slit2 level was more decreased in diabetic group than in control group, but there was no significant difference statistically. Interestingly, serum levels of Slit2 were significantly negatively correlated to the serum concentrations of fasting glucose (coefficient r=-0.246, P=0.008), the serum concentrations of postprandial glucose (coefficient r=-0.233, P=0.017), and glycosylated hemoglobin (HbA1c; coefficient r=-0.357, P<0.001).

CONCLUSION

From our study, the first report of circulating Slit2 levels in human, circulating Slit2 level significantly negatively correlated with serum glucose and HbA1c. Our results suggest that the circulating Slit2 may play a role in maintainence of glucose homeostasis in human, even though exact contribution and mechanism are not yet known.

Mitochondrial energy deficiency leads to hyperproliferation of skeletal muscle mitochondria and enhanced insulin sensitivity

Diabetes is associated with impaired glucose metabolism in the presence of excess insulin. Glucose and fatty acids provide reducing equivalents to mitochondria to generate energy, and studies have reported mitochondrial dysfunction in type II diabetes patients. If mitochondrial dysfunction can cause diabetes, then we hypothesized that increased mitochondrial metabolism should render animals resistant to diabetes. This was confirmed in mice in which the heart-muscle-brain adenine nucleotide translocator isoform 1 (ANT1) was inactivated. ANT1-deficient animals are insulin-hypersensitive, glucose-tolerant, and resistant to high fat diet (HFD)-induced toxicity. In ANT1-deficient skeletal muscle, mitochondrial gene expression is induced in association with the hyperproliferation of mitochondria. The ANT1-deficient muscle mitochondria produce excess reactive oxygen species (ROS) and are partially uncoupled. Hence, the muscle respiration under nonphosphorylating conditions is increased. Muscle transcriptome analysis revealed the induction of mitochondrial biogenesis, down-regulation of diabetes-related genes, and increased expression of the genes encoding the myokines FGF21 and GDF15. However, FGF21 was not elevated in serum, and FGF21 and UCP1 mRNAs were not induced in liver or brown adipose tissue (BAT). Hence, increased oxidation of dietary-reducing equivalents by elevated muscle mitochondrial respiration appears to be the mechanism by which ANT1-deficient mice prevent diabetes, demonstrating that the rate of mitochondrial oxidation of calories is important in the etiology of metabolic disease.