Reduced circulating levels of TWEAK are associated with gestational diabetes mellitus

The TWEAK/Fn14/CD163 axis-implications for metabolic disease

TWEAK (tumor necrosis factor-like weak inducer of apoptosis) is a member of the TNF superfamily that controls a multitude of cellular events including proliferation, migration, differentiation, apoptosis, angiogenesis, and inflammation. TWEAK control of these events is via an expanding list of intracellular signalling pathways which include NF-κB, ERK/MAPK, Notch, EGFR and AP-1. Two receptors have been identified for TWEAK - Fn14, which targets the membrane bound form of TWEAK, and CD163, which scavenges the soluble form of TWEAK. TWEAK appears to elicit specific events based on the receptor to which it binds, tissue type in which it is expressed, specific extrinsic conditions, and the presence of other cytokines. TWEAK signalling is protective in healthy tissues, but in chronic inflammatory states become detrimental to the tissue. Consistent data show a role for the TWEAK/FN14/CD163 axis in metabolic disease, chronic autoimmune diseases, and acute ischaemic stroke. Low circulating concentrations of soluble TWEAK are predictive of poor cardiovascular outcomes in those with and without diabetes. This review details the current understanding of the TWEAK/Fn14/CD163 axis as one of the chief regulators of immune signalling and its cell-specific role in metabolic disease development and progression.

Circulating sTweak is associated with visceral adiposity and severity in patients with obstructive sleep apnea syndrome

Hypoxia is linked to an inflammatory imbalance in obstructive sleep apnea syndrome (OSAS). Circulating soluble tumor necrosis factor (TNF)-like weak inducer of apoptosis (sTWEAK) is a cytokine that regulates inflammation and insulin resistance in adipose tissue. This study first investigated sTWEAK concentrations in patients OSAS and evaluated associations between sTWEAK concentrations and visceral adiposity, metabolic dysfunction, and hypoxia observed in OSAS. Forty age, sex, and body mass index-matched patients with simple habitual snoring (HSS) and 70 patients with OSAS were included. Patients were divided according to OSAS severity: mild-moderate (apnea–hypopnea index, AHI 5–30 events/h) and severe (AHI ≥ 30 events/h). Anthropometric data, glucose metabolism, visceral fat (VF) ratio, and sTWEAK levels were compared. sTWEAK levels were higher in the OSAS group than in the HSS group (931.23 ± 136.48 vs. 735.22 ± 102.84 ng/L, p = 0.001). sTWEAK levels were higher in severe OSAS than in mild-moderate OSAS (1031.83 ± 146.69 vs. 891.01 ± 110.01 ng/L, p = 0.002. When we evaluated the sTWEAK value and AHI, VF ratio, total cholesterol, blood pressure, homeostasis model of assessment-insulin resistance, and high-sensitivity C-reactive protein using multiple regression analysis, a significant correlation was found between sTWEAK levels and AHI (p < 0.001). It was found that sTWEAK levels were not correlated with glucose metabolism and VF ratio. Increased circulating sTWEAK levels were associated with the severity of OSAS. High sTWEAK levels were correlated with increased AHI. sTWEAK concentrations are linked to severe OSAS.

Omics-based biomarkers in the diagnosis of diabetes

Diabetes mellitus (DM) is a group of metabolic diseases related to the dysfunction of insulin, causing hyperglycaemia and life-threatening complications. Current early screening and diagnostic tests for DM are based on changes in glucose levels and autoantibody detection. This review evaluates recent studies on biomarker candidates in diagnosing type 1, type 2 and gestational DM based on omics classification, whilst highlighting the relationship of these biomarkers with the development of diabetes, diagnostic accuracy, challenges and future prospects. In addition, it also focuses on possible non-invasive biomarker candidates besides common blood biomarkers.

Soluble CD163 and TWEAK in early pregnancy gestational diabetes and later glucose intolerance

Gestational diabetes mellitus (GDM) is today universally diagnosed during late pregnancy. Treating hyperglycaemia during pregnancy reduces the risk of complications, the effect of interventions is however limited due to the late diagnosis. It is thus important to identify biomarkers reaching a high precision for GDM development in early pregnancy. Here we aim to investigate soluble CD163 (sCD163) and soluble tumour necrosis factor-like weak inducer of apoptosis (sTWEAK) in early pregnancy GDM and their association to the development of later glucose intolerance. In this case-control study, women diagnosed with GDM in early pregnancy (n = 70) at Lund University Hospital, Lund, Sweden in 2011-2015 were age- and BMI matched to pregnant volunteers without diabetes (n = 70) recruited in early pregnancy from maternal health care centres in 2014-2015. Plasma levels of sCD163 and sTWEAK were analysed using commercial ELISA. Plasma levels of sCD163 did not differ between patients with and without GDM in early pregnancy (p = 0.86), plasma levels of sTWEAK however was decreased in women with GDM (0.71 [0.4-1.75] ng/ml) compared to controls (1.38 [0.63-4.86] ng/ml; p = 0.003). Women with sTWEAK levels in the lowest tertile had an increased risk of GDM in early pregnancy (p = 0.014). Neither sCD163 nor sTWEAK were associated with later glucose intolerance in women with GDM. This study reports decreased levels of sTWEAK in women with early pregnancy GDM, independent of age and BMI. Neither sCD163 nor sTWEAK were found to be associated to later glucose intolerance.

Serum sTWEAK levels in chronic periodontitis and type 2 diabetes mellitus

AIM

The two-way relationship between diabetes mellitus and periodontitis has been extensively studied with various interconnected biomarkers sharing a link. Soluble Tumour Necrosis Factor-like Weak inducer of apoptosis (sTWEAK) is gaining attention as an important mediator in chronic inflammatory diseases. Thus, the aim of this study was to detect, estimate and compare the levels of sTWEAK in the serum of health, chronic periodontitis (CP), and CP with type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

Forty-five participants between 18 and 65 years were divided into groups of 15 each as Group 1: healthy, Group 2: CP, and Group 3: CP + T2DM. Clinical periodontal parameters and glycemic status were assessed. sTWEAK in serum was estimated using a commercially available ELISA kit. The data was statistically analyzed.

RESULTS

sTWEAK was detected in all participants. Significant differences were observed between the groups for sTWEAK; highest in health, lower in CP and lowest in CP + T2DM. In the diseased groups, the clinical and glycemic parameters correlated positively with each other, whereas sTWEAK correlated negatively with each of the parameters.

CONCLUSION

The literature reports lower concentrations of systemic sTWEAK in T2DM which may be comparable to our observations in CP + T2DM when compared to health and its negative correlation with all the parameters suggesting an association with both clinical periodontal parameters and glycemic levels. However, serum sTWEAK levels may not be necessarily elevated in periodontitis as previously reported, and hence has the potential to be studied extensively for clarification with its association with T2DM.

Evaluation of soluble TNF-like weak inducer of apoptosis (sTWEAK) levels to predict preeclampsia in early weeks of pregnancy

INTRODUCTION

Soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) is linked to endothelial dysfunction; a key factor in pre-eclamptic pathogenesis. This study aimed to compare sTWEAK levels during pregnancy to assess for its prognostic ability.

MATERIALS AND METHODS

Sixty three high risk pregnant women were followed up from 12 weeks of gestation till term. Serum levels of sTWEAK and platelet derived growth factor (PlGF), blood pressure, serum glucose, uric acid, urea/creatinine and liver function tests were measured. Subjects were stratified according to the ACOG criteria as women who developed PE, or PIH or remained normotensive at term. A negative control group of normotensive healthy pregnant women (n = 17) was also recruited for comparison.

RESULTS

Baseline sTWEAK levels were lower (4.03 ± 0.37 ng/dl) in HR cohort that developed PE and further reduced at term (1.93 ± 0.23 ng/dl) as compared to HR subjects who remained normotensive and negative control group (30.53 ± 0.79 ng/dl; p < 0.01). Likewise PlGF levels were significantly lower (74.22 ± 10.11 pg/ml) in HR cohort that developed PE (p = 0.013). At term 39.68% (n = 22) HR subjects with low sTWEAK developed PIH and 34.92% (n = 24) developed PE. In terms of high risk characteristics observed in the HR group; 73% of the subjects were multiparous, whereas 26.98% reported to have developed PE in previous pregnancies.

CONCLUSION

sTWEAK levels at early pregnancy weeks were found to be low in high risk females who developed PE at follow up versus normotensive pregnant women. Baseline TWEAK might serve as an independent variable for prediction of pre-eclampsia; however longitudinal studies with larger sample size are required to ascertain the causal relation.

TWEAK and monocyte to HDL ratio as a predictor of metabolic syndrome in patients with polycystic ovary syndrome

We aimed at analyzing serum TWEAK levels and monocyte/HDL ratio in polycystic ovary syndrome (PCOS) and their predictivity for metabolic syndrome (MS) in PCOS. We included 71 women with PCOS and 40 healthy controls without any cardiovascular risk factors in this cross-sectional study. Patient group was classified as MS positive (n = 34) and negative (n = 37). Study group had higher monocyte/HDL ratio and TWEAK levels (9.59 ± 2.82 vs 8.2 ± 2.46, p = .007 and 1085.54 ± 780.95 vs 694.88 ± 369.67 ng/ml, p = .009). Monocyte/HDL ratio and TWEAK levels were higher in MS positive group (10.47 ± 2.81 vs 8.77 ± 2.61, p = .01 and 1417.59 ± 921.52 vs 780.41 ± 455.67, p = .009). In multivariate regression analysis, monocyte/HDL ratio (>9.9, OR 3.42, 95%CI 1.41-5.78, p = .008) and TWEAK (>846.5 ng/ml, OR 5.49, 95%CI 3.14-7.59, p = .002) were found to be independent predictors of MS in study group. Discriminative value of monocyte/HDL ratio for MS in study group was evaluated by receiver operating curve. Area under curve for monocyte/HDL ratio was 0.669 with a sensitivity of 70.3% and specifity of 67.7%, cutoff value was >9.9. Receiver operating curve for TWEAK at >846.5 pg/ml threshold to diagnose MS in study group was performed and area under the curve was 0.769 with a sensitivity of 73% and specifity of 72%. TWEAK and monocyte/HDL ratio may be promising in predicting MS at early stages in PCOS to prevent future cardiovascular diseases by modifying life-style or giving pharmacotheraphy.

The C-terminal region of tumor necrosis factor like weak inducer of apoptosis is required for interaction with advanced glycation end products

Previously, we found that endogenously produced pro-inflammatory molecules, advanced glycation end products (AGEs), interact with tumor necrosis factor-like weak inducer of apoptosis (TWEAK), and attenuate its immunomodulatory function. In the present study, to elucidate the mechanism by which AGEs attenuate TWEAK function, we searched for regions responsible for TWEAK-AGE interaction using TWEAK deletion mutants. Pull-down assays with the TWEAK mutants and AGEs revealed that the C-terminal half of TWEAK, which is the region essential for receptor stimulation, was required for this interaction. On the other hand, the N-terminal deletion mutants did not exhibit a significant decrease in AGE binding. Moreover, a moderate decrease in the AGE binding by double-deletion in quartered C-terminal half regions and a substantial decrease by triple-deletion in this region were observed. In addition, full-length TWEAK stimulated IL-8 gene expression in endothelial EA.hy.926 cells, whereas the triple-deletion mutant lost much of this activity, suggesting that the TWEAK-AGE interaction sites overlap with the region needed to exert normal function of TWEAK. Our present findings may help to elucidate the pathophysiological roles of the TWEAK-AGE interaction for prevention and treatment of AGE-related inflammatory diseases.

Soluble Tumor Necrosis Factor (TNF)-Like Weak Inducer of Apoptosis (Tweak) Independently Predicts Subclinical Atherosclerosis in Behcet's Disease

BACKGROUND

Vasculopathy is a major cause of mortality and morbidity in Behcet's Disease (BD). Subclinical atherosclerosis can even be detected in the early stage of BD. Soluble tumor necrosis factor-like (TNF) weak inducer of apoptosis (TWEAK) is known as a good marker of the inflammation in vascular tree. The aim of this study is to examine the relationship between carotid artery intima-media thickness (cIMT) and serum TWEAK levels in patients with BD.

MATERIALS AND METHODS

In line with International BD Study Group criteria, 48 BD, and 30 controls were included in our study. Disease activity was evaluated according to BD current activity form (BDCAF). C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), lipid parameters, serum TWEAK levels, and cIMT were measured.

RESULTS

Disease activity score of BD patients was found as 2 (range 0-7). cIMT, serum TWEAK, CRP and ESR levels of BD patients were significantly higher comparing to cIMT (0.62 ± 0.13 mm vs. 0.43 ± 0.09 mm, p < 0.001), serum TWEAK (667.5 ± 130.6 vs. 603.4 ± 89.6 pg/ml, p = 0.015), CRP (3.9 ± 4.3 vs. 1.4 ± 1.0 mg/dl, p < 0.001) and ESR (10.2 ± 10.0 vs. 5.6 ± 3.7 mm/h, p = 0.005) levels of the control group. There was a positive correlation between serum TWEAK level and disease activity (r = 0.251, p = 0.030) and cIMT (r = 0.463, p < 0.001). Our study also revealed an independent correlation between cIMT and serum TWEAK levels (beta = 0.354, p < 0.001).

CONCLUSION

Increased serum TWEAK levels can play a part in the development of atherosclerotic heart disease in BD. Due to their liability to atherosclerosis, patients with BD must followed closely.

Alterations of soluble TWEAK and CD163 concentrations in patients with chronic heart failure

Inflammatory activation plays a pivotal role in chronic heart failure with reduced ejection fraction (HF-REF). A novel mediator from TNF family: soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) along its soluble decoy receptor CD163 (sCD163) recently has been investigated in other cardiovascular pathologies. We aimed to evaluate sTWEAK and sCD163 concentrations in HF-REF patients. The study enrolled 79 patients with stable HF-REF, EF < 35%. The control population without history of heart failure included two groups: 26 comorbidities matched patients and 27 healthy volunteers. sTWEAK and sCD163 serum concentrations were determined using ELISA kits. Univariate and multivariate analysis was performed to assess variables affecting concentration of sTWEAK and sCD163. HF-REF patients were characterized by higher sTWEAK (median 374 IQR: 321-429 vs 201 IQR: 145-412pg/ml, P=0.005), sCD163 (median 744 IQR: 570-1068 vs 584 IQR: 483-665pg/ml, P=0.03) concentrations and sTWEAK/sCD163 ratio (median 0.53 IQR: 0.32-0.7 vs 0.3 IQR: 0.22-0.37, P=0.001) comparing to healthy volunteers. Comparing to comorbidities matched controls, HF-REF patients had lower sTWEAK levels (median 374 IQR: 321-429 vs 524 IQR: 384-652pg/ml; P=0.002), while sCD163 and sTWEAK/sCD163 ratio didn't differ. Concentration of sTWEAK in HF-REF was affected by white blood cell count and aspirin intake, while sCD163 by exercise capacity, LV diastolic volume, CRP and presence of arterial hypertension.

CONCLUSIONS

HF-REF patients present increased sTWEAK and sCD163 levels as well as sTWEAK/sCD163 ratio when compared to healthy subjects, however CHF itself appears to be associated with down-regulation of sTWEAK.

Soluble TNF-Like Weak Inducer of Apoptosis as a New Marker in Preeclampsia: A Pilot Clinical Study

Introduction. All findings of preeclampsia appear as the clinical consequences of diffuse endothelial dysfunction. Soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) was recently introduced as a TNF related cytokine in various inflammatory and noninflammatory disorders. sTWEAK was found to be related to endothelial dysfunction in patients with chronic kidney disease. In our study we aimed to compare sTWEAK levels in women with preeclampsia to corresponding levels in a healthy pregnant control group. Materials and Methods. The study was undertaken with 33 patients with preeclampsia and 33 normal pregnant women. The concentration of sTWEAK in serum was calculated with an enzyme linked immunosorbent assay (ELISA) kit. Results. Serum creatinine, uric acid, LDH levels, and uPCR were significantly higher in the patient group compared to the control group. sTWEAK levels were significantly lower in preeclamptic patients (332 ± 144 pg/mL) than in control subjects (412 ± 166 pg/mL) (p = 0.04). Discussion. Our study demonstrates that sTWEAK is decreased in patients with preeclampsia compared to healthy pregnant women. There is a need for further studies to identify the role of sTWEAK in the pathogenesis of preeclampsia and to determine whether it can be regarded as a predictor of the development of preeclampsia.