Omentin-1 ameliorates pulmonary arterial hypertension by inhibiting endoplasmic reticulum stress through AMPKα signaling

BACKGROUND

Endothelial dysfunction of the pulmonary artery contributes to hypoxia-induced pulmonary arterial hypertension (PAH). Omentin-1, as a novel adipocytokine, plays an important protective role against cardiovascular diseases. However, the effect and underlying mechanisms of omentin-1 against PAH remain unclear.

METHODS

PAH was induced in SD (Sprague & Dawley) rats via a low-oxygen chamber for 4 weeks. Hemodynamic evaluation was undertaken using a PowerLab data acquisition system, and histopathological analysis was stained with hematoxylin and eosin (H&E). Endothelial function of pulmonary artery was assessed using wire myography.

RESULTS

We found that omentin-1 significantly improved pulmonary endothelial function in rats exposed to hypoxia and attenuated PAH. Mechanistically, we found that omentin-1 increased phosphorylated 5'‑adenosine monophosphate‑activated protein kinase (p‑AMPK) level and reduced endoplasmic reticulum (ER) stress and increased NO production in pulmonary artery from rats exposed to hypoxia. However, the effect of omentin-1 was abolished by treatment with AMPK inhibitor (Compound C).

CONCLUSIONS

Our results reveal a protective effect of omentin-1 in PAH via inhibiting ER stress through AMPKα signaling and provide an agent with translational potential for the treatment of PAH.

Omentin-1 inhibits the development of benign prostatic hyperplasia by attenuating local inflammation

BACKGROUND

Benign prostatic hyperplasia (BPH) is a prevalent disease affecting elderly men, with chronic inflammation being a critical factor in its development. Omentin-1, also known as intelectin-1 (ITLN-1), is an anti-inflammatory protein primarily found in the epithelial cells of the small intestine. This study aimed to investigate the potential of ITLN-1 in mitigating BPH by modulating local inflammation in the prostate gland.

METHODS

Our investigation involved two in vivo experimental models. Firstly, ITLN-1 knockout mice (Itln-1-/-) were used to study the absence of ITLN-1 in BPH development. Secondly, a testosterone propionate (TP)-induced BPH mouse model was treated with an ITLN-1 overexpressing adenovirus. We assessed BPH severity using prostate weight index and histological analysis, including H&E staining, immunohistochemistry, and enzyme-linked immunosorbent assay. In vitro, the impact of ITLN-1 on BPH-1 cell proliferation and inflammatory response was evaluated using cell proliferation assays and enzyme-linked immunosorbent assay.

RESULTS

In vivo, Itln-1-/- mice exhibited elevated prostate weight index, enlarged lumen area, and higher TNF-α levels compared to wild-type littermates. In contrast, ITLN-1 overexpression in TP-induced BPH mice resulted in reduced prostate weight index, lumen area, and TNF-α levels. In vitro studies indicated that ITLN-1 suppressed the proliferation of prostate epithelial cells and reduced TNF-α production in macrophages, suggesting a mechanism involving the inhibition of macrophage-mediated inflammation.

CONCLUSION

The study demonstrates that ITLN-1 plays a significant role in inhibiting the development of BPH by reducing local inflammation in the prostate gland. These findings highlight the potential of ITLN-1 as a therapeutic target in the management of BPH.

Omentin-1 ameliorates the progress of osteoarthritis by promoting IL-4-dependent anti-inflammatory responses and M2 macrophage polarization

Osteoarthritis (OA) is a prevalent joint disease commonly associated with aging and obesity, which can lead to pain, stiffness, joint dysfunction, and disability. Omentin-1 (also called intelectin-1) is a newly discovered adipokine, which plays a protective role in suppressing the secretion of pro-inflammatory cytokines. Based on data from the Gene Expression Omnibus (GEO) dataset and clinical samples obtained at our institution revealed, determined that omentin-1 and IL-4 (an anti-inflammatory cytokine) levels were significantly lower in OA patients than in normal controls. Omentin-1 was shown to induce IL-4-depedent anti-inflammatory responses and M2 macrophage polarization in OA synovial fibroblasts via the PI3K, ERK, and AMPK pathways. Administering omentin-1 was shown to block cartilage degradation and bone erosion resulting from anterior cruciate ligament transection by inhibiting the production of pro-inflammatory cytokines and promoting M2 macrophage polarization in vivo. Our findings indicate omentin-1 as a promising therapeutic avenue for the treatment for OA.

Omentin-1 enhances the inhibitory effect of endothelial progenitor cells on neointimal hyperplasia by inhibiting the p38 MAPK/CREB pathway

AIMS

Endothelial progenitor cells (EPCs) play an important role in vascular repair. However, they are dysfunctional in the inflammatory microenvironment during restenosis. In this study, we investigated whether omentin-1, an anti-inflammatory factor, could reduce neointima formation after carotid artery injury (CAI) in rats by improving EPC functions that were damaged by inflammation and the underlying mechanisms.

MAIN METHODS

EPCs were transfected with adenoviral vectors expressing human omentin-1 or green fluorescent protein (GFP). Then, the rats received 2 × 106 EPCs expressing omentin-1 or GFP by tail vein injection directly after CAI and again 24 h later. Hematoxylin-eosin staining and immunohistochemistry were used for analyzing neointimal hyperplasia. Besides, EPCs were treated with omentin-1 and TNF-α to examine the underlying mechanism.

KEY FINDINGS

Our results showed that omentin-1 could significantly improve EPC functions, including proliferation, apoptosis and tube formation. Meanwhile, EPCs overexpressed with omentin-1 could significantly reduce neointimal hyperplasia and tumor necrosis factor-α (TNF-α) expression after CAI in rats. TNF-α could notably induce EPC dysfunction, which could be markedly reversed by omentin-1 through the inhibition of the p38 MAPK/CREB pathway. Furthermore, a p38 MAPK agonist (anisomycin) significantly abrogated the protective effects of omentin-1 on EPCs damaged by TNF-α.

SIGNIFICANCE

Our results indicated that genetically modifying EPC with omentin-1 could be an alternative strategy for the treatment of restenosis.

Omentin-1 induces mechanically activated fibroblasts lipogenic differentiation through pkm2/yap/pparγ pathway to promote lung fibrosis resolution

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease characterized by extensive extracellular matrix (ECM) deposition by activated myofibroblasts, which are specialized hyper-contractile cells that promote ECM remodeling and matrix stiffening. New insights on therapeutic strategies aimed at reversing fibrosis by targeting myofibroblast fate are showing promise in promoting fibrosis resolution. Previously, we showed that a novel adipocytokine, omentin-1, attenuated bleomycin (BLM)-induced lung fibrosis by reducing the number of myofibroblasts. Apoptosis, deactivation, and reprogramming of myofibroblasts are important processes in the resolution of fibrosis. Here we report that omentin-1 reverses established lung fibrosis by promoting mechanically activated myofibroblasts dedifferentiation into lipofibroblasts. Omentin-1 promotes myofibroblasts lipogenic differentiation by inhibiting dimerization and nuclear translocation of glycolytic enzymes pyruvate kinase isoform M2 (PKM2) and activation of the downstream Yes-associated protein (YAP) by increasing the cofactor fructose-1,6-bisphosphate (F1, 6BP, FBP). Moreover, omentin-1 activates proliferator-activated receptor gamma (PPARγ) signaling, the master regulator of lipogenesis, and promotes the upregulation of the lipogenic differentiation-related protein perilipin 2 (PLIN2) by suppressing the PKM2-YAP pathway. Ultimately, omentin-1 facilitates myofibroblasts transformation into the lipofibroblast phenotype, with reduced collagen synthesis and enhanced degradation properties, which are crucial mechanisms to clear the ECM deposition in fibrotic tissue, leading to fibrosis resolution. Our results indicate that omentin-1 targets mechanical signal accelerates fibrosis resolution and reverses established lung fibrosis by promoting myofibroblasts lipogenic differentiation, which is closely associated with ECM clearance in fibrotic tissue. These findings suggest that targeting mechanical force to promote myofibroblast lipogenic differentiation is a promising therapeutic strategy against persistent lung fibrosis.

Omentin-1 ameliorates experimental inflammatory bowel disease via Nrf2 activation and redox regulation

AIMS

Omentin-1 production is decreased in patients with IBD. However, the specific role of Omentin-1 in IBD has not been fully elucidated. This study aimed to investigate the expression and role of Omentin-1 in IBD and the potential mechanisms.

MAIN METHODS

We collected human serum and colon biopsy samples at the Wuhan Union Hospital. Omentin-1 recombinant protein was injected intraperitoneally in a DSS-induced experimental IBD mouse model. Omentin-1 levels were measured in IBD patients, colitis mice, and LPS-induced HT-29 cells. Omentin-1 and/or a Nrf2 specific inhibitor (ML385) were administered to DSS mice and LPS-induced HT-29 cells. The effects of Omentin-1 on inflammation, intestinal barrier function, Nrf2 pathway, oxidative stress, and NF-κB signaling were detected in vivo and in vitro.

KEY FINDINGS

Serum Omentin-1 levels were significantly reduced in UC and CD patients compared with controls (173.7 (IQR, 120.1-221.2) ng/ml, 80.8 (43.8-151.8) ng/ml, and 270.7 (220.7-306.5) ng/ml, respectively). The levels of Omentin-1 were also significantly lower in colitis mice and LPS-induced HT-29 cells. Omentin-1 treatment effectively ameliorated inflammation and impaired intestinal barrier, decreased ROS and MDA levels, and increased GSH and SOD production in the DSS-induced colitis mice and LPS-induced HT-29 cells. Mechanically, Omentin-1 repaired the intestinal barrier by activating Nrf2, then improving oxidative stress and inhibiting NF-κB signaling. Furthermore, the interaction between Omentin-1 and Nrf2 was identified.

SIGNIFICANCE

Omentin-1 activates the Nrf2 pathway to regulate redox balance, ultimately protecting intestinal barrier function and reducing intestinal inflammation. In general, Omentin-1 can be used as a promising therapeutic target for IBD.

Aerobic Exercise Training Effects on Omentin-1, Insulin Resistance, and Lipid Profile Among Male Smokers

Background: Omentin-1 is a circulating adipokine that can serve as a biomarker for assessment of metabolic risk factors. We investigated the effect of eight weeks of aerobic exercise training on serum omentin-1, insulin resistance and lipid profile in nonsmokers and smokers. Methods: Nineteen male nonsmokers (aged 27.88 ± 2.47 years, and with BMI of 22.69 ± 1.77 kg.m-2) and twenty male smokers (aged 30.11 ± 1.96 years, and with BMI of 23.12 ± 1.91 kg.m-2) were randomly assigned into nonsmokers control group (C), nonsmokers exercise group (E), control smoker group (CS), and exercise smoker group (ES). Exercise groups participated in an eight-week aerobic exercise training program (three times a week, 20-35 min per session at 55%-70% of maximum heart rate). Serum omentin-1 and insulin values were determined by ELISA. The Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), glucose level and lipid profile were measured before and after the intervention. Pearson correlation test, Eta test, paired samples t-test, one and two-way analysis of variance (ANOVA) and post-hoc Tukey test were applied for data analysis (p < .05). Results: Aerobic exercise improved both serum omentin-1 and high lipoprotein cholesterol (HDL-C) in the exercise groups (P < .05). Also, exercise training reduced insulin, glucose, HOMA-IR, triglyceride (TG), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels (p < .05). Omentin-1 was significantly correlated with glucose, insulin, HOMA-IR, TG, TC, LDL-C and HDL-C in both nonsmokers and smokers. Conclusions: The findings suggest that aerobic exercise-induced changes in omentin-1 in the exercise-trained groups may be associated with the beneficial effects of exercise on reduced insulin resistance and lipid profile.

Role of omentin-1 in susceptibility to anxiety and depression like behaviors

Neuro-inflammation and blood-brain barrier (BBB) dysfunction are associated with depression. Evidence shows that adipokines enter the brain from the circulation, which regulates depressive behaviors. Omentin-1 is a newly identified adipocytokine that has anti-inflammatory effects, but little is known about its role in neuro-inflammation and mood-relevant behavior. Our results showed omentin-1 knockout mice (Omentin-1-/-) increased susceptibility to anxiety and depressive-like behaviors, which are associated with abnormalities of cerebral blood flow (CBF) and impaired BBB permeability. Moreover, omentin-1 depletion significantly increased hippocampal pro-inflammatory cytokines (IL-1β, TNFα, IL-6), caused microglial activation, inhibited hippocampus neurogenesis, and resulted in autophagy impairment by dysregulating ATG genes. Omentin-1 deficiency also sensitized mice to the behavioral changes induced by lipopolysaccharide (LPS), suggesting that omentin-1 could rescue neuro-inflammation by acting as an anti-depressant. Our in vitro microglia cell culture data confirmed that recombinant omentin-1 suppresses microglial activation and pro-inflammatory cytokine expression induced by LPS. Our study suggests that omentin-1 can be used as a promising therapeutic agent for the prevention or treatment of depression by providing a barrier-promoting effect and an endogenous anti-inflammatory balance to downregulate the proinflammatory cytokines.

Omentin-1 and diabetes: more evidence but far from enough

AIMS AND BACKGROUND

Omentin-1 (oment-1) is a type of adipokines that is mainly expressed in visceral fat tissue. Based on accumulating evidence, oment-1 is closely related to diabetes and its complications. However, so far data about oment-1 and diabetes is fragmented. In this review, we focus on the role of oment-1 on diabetes, including its possible signalling pathways, the correlation of circulating omens-1 levels with diabetes and its complications.

METHODS

The web of PubMed was searched for articles of relevant studies published until February, 2023.

RESULTS AND CONCLUSIONS

Oment-1 might exert its effects by inhibiting the NF-κB pathway and activating the Akt and AMPK-dependent pathways. The level of circulating oment-1 is negatively correlated with the occurrence of type 2 diabetes and some complications, including diabetic vascular disease, cardiomyopathy, and retinopathy, which can be affected by anti-diabetic therapies. Oment-1 could be a promising marker for screening and targeted therapy for diabetes and its complications; however, more studies are still needed.

Omentin-1 drives cardiomyocyte cell cycle arrest and metabolic maturation by interacting with BMP7

Mammalian cardiomyocytes (CMs) undergo maturation during postnatal heart development to meet the increased demands of growth. Here, we found that omentin-1, an adipokine, facilitates CM cell cycle arrest and metabolic maturation. Deletion of omentin-1 causes mouse heart enlargement and dysfunction in adulthood and CM maturation retardation in juveniles, including delayed cell cycle arrest and reduced fatty acid oxidation. Through RNA sequencing, molecular docking analysis, and proximity ligation assays, we found that omentin-1 regulates CM maturation by interacting directly with bone morphogenetic protein 7 (BMP7). Omentin-1 prevents BMP7 from binding to activin type II receptor B (ActRIIB), subsequently decreasing the downstream pathways mothers against DPP homolog 1 (SMAD1)/Yes-associated protein (YAP) and p38 mitogen-activated protein kinase (p38 MAPK). In addition, omentin-1 is required and sufficient for the maturation of human embryonic stem cell-derived CMs. Together, our findings reveal that omentin-1 is a pro-maturation factor for CMs that is essential for postnatal heart development and cardiac function maintenance.

Omentin-1 promotes mitochondrial biogenesis via PGC1α-AMPK pathway in chondrocytes

OBJECTIVE

Omentin-1 is a newly discovered metabolic regulatory adipokine. Studies have shown that omentin-1 possesses pleiotropic effects in different types of cells. This study aims to investigate the regulation by omentin-1 on mitochondrial biogenesis in chondrocytes.

METHODOLOGY

C-28/I2 chondrocytes were treated with omentin-1 (150 and 300 ng/ml) for 24 h. The expression of mitochondrial regulators, markers and the DNA copy was assessed. The mitochondrial morphology was observed by electron microscopy. The mitochondrial respiratory rate and ATP production in chondrocytes were measured by cell lysates.

RESULTS

Omentin-1 treatment up-regulated PGC-1α, NRF-1 and mitochondrial transcription factor A (TFAM) in cultured chondrocytes, indicating that omentin-1 could be involved in the regulation of mitochondrial function. Omentin-1 promoted mtDNA/nDNA and four mitochondrial genes (Tomm20, Tomm40, Timm9 and Atp5c1), mRNA transcripts as well as two mitochondrial protein expressions (SDHB and MTCO1). At a cellular level, omentin-1 enhanced the mitochondrial respiratory rate and ATP production. Mechanistically, we proved that omentin-1 increased AMPKα activation, and the blockage of AMPKα by its inhibitor compound C abolished the inductive effect of omentin-1 on PGC1α expression and mtDNA/nDNA ratio, indicating that the effect of omentin-1 is dependent on AMPKα activation.

CONCLUSION

Omentin-1 is a positive regulator of mitochondrial biogenesis in chondrocytes, and its action is dependent on the AMPK-PGC1α pathway. This study, therefore, implies that omentin-1 has the potential to remedy chondrocyte damage in the prevention and treatment of osteoarthritis.

Role of major adipokines in hypertension: A literature review

The incidence and prevalence of hypertension are increasing as a consequence of the obesity epidemic. Adipocytes and their variety of factors make contributions to the long-term regulation of blood pressure. The pathophysiologic states of hypertension, including obesity, are regulated by the production of adipocyte-derived factors. Increased body mass index was closely linked to elevated blood pressure. Mostly the hypertensive subjects were obese as well as overweight. There are numerous adipokines, however, this review article only focuses on the major adipokines including chemerin, visfatin, retinol-binding protein 4, plasminogen activator inhibitor-1, monocyte chemotactic protein-1, omentin-1, lipocalin-2, vaspin, progranulin, complement c1q tumor necrosis factor-related protein, and nesfatin-1 role in the pathogenesis of hypertension. This review article concludes the significant association of major adipokines in the pathogenesis of hypertensives. New research should be focused on other newly reported adipokine roles in hypertensive subjects and the management of these adipokines in hypertensive subjects. The discovery of this information could result in the creation of antihypertensive medications, particularly those that focus on obesity-related hypertension.

Correlation of serum omentin-1 level with clinical features and major adverse cardiac and cerebral events in patients undergoing continuous ambulatory peritoneal dialysis

Omentin-1 shows a critical protective role of cardiovascular events in chronic kidney disease. This study aimed to further assess serum omentin-1 level and its relationship with clinical features and accumulating major adverse cardiac/cerebral events (MACCE) risk in end-stage renal disease patients undergoing continuous ambulatory peritoneal dialysis (CAPD-ESRD). Totally, 290 CAPD-ESRD patients and 50 healthy controls (HCs) were recruited, and their serum omentin-1 levels were measured by enzyme-linked immunosorbent assay. All CAPD-ESRD patients were followed up for 36 months to assess accumulating MACCE rate. Omentin-1 level in CAPD-ESRD patients was lower than that in HCs [median (interquartile range): 229.350 (153.575-355.550) vs. 449.800 (354.125-527.450) pg/mL] (p < 0.001). Moreover, omentin-1 level was inversely related to C-reactive protein (CRP) (p = 0.028), total cholesterol (p = 0.023), and low-density lipoprotein cholesterol (p = 0.005), while there was no correlation in omentin-1 level with other clinical features in CAPD-ESRD patients. The accumulating MACCE rate was 4.5%, 13.1%, and 15.5% in the first, second, and third years respectively, and it was lower in CAPD-ESRD patients with high level of omentin-1 than those with low level of omentin-1 (p = 0.004). Furthermore, omentin-1 (hazard ratio (HR)=0.422, p = 0.013) and high-density lipoprotein cholesterol (HR = 0.396, p = 0.010) were independently associated with reduced accumulating MACCE rate; while age (HR = 3.034, p = 0.006), peritoneal dialysis duration (HR = 2.741, p = 0.006), CRP (HR = 2.289, p = 0.026), serum uric acid (HR = 2.538, p = 0.008) were independently related to higher accumulating MACCE rate in CAPD-ESRD patients. In conclusion, serum high omentin-1 level is associated with decreased inflammation, lipid levels, and accumulating MACCE risk in CAPD-ESRD patients.

SERUM OMENTIN-1 LEVEL IS ASSOCIATED WITH THE AGGREGATION OF CARDIOVASCULAR RISK FACTORS IN ADOLESCENTS

Objective

The existing studies involving omentin-1 have mainly focused on relationships with single cardiovascular risk factor. Whether omentin-1 is associated with the aggregation of cardiovascular risk factors has not been reported. We investigate the relationship between the serum omentin-1 level and aggregation of cardiovascular risk factors in adolescents.

Subjects and Methods

A total of 741 young students, 11-16 years of age, were enrolled using a stratified cluster sampling method. The participants were given a questionnaire survey and underwent a physical examination. The aggregation of cardiovascular risk factors was defined as two or more cardiovascular risk factors occurring simultaneously in the same individual.

Results

Partial correlation analysis suggested that serum omentin-1 level was significantly correlated with waist circumference (R=-0.086, P=0.019) and Body Mass Index (R=-0.096, P=0.009). Logistic regression analysis showed that as the serum omentin-1 level increased, the risk of aggregation of cardiovascular risk factors decreased. Cardiovascular risk factors which were most closely associated with a decrease in the serum omentin-1 level were obesity calculated by Body Mass Index (OR=0.988, P=0.043) and central obesity calculated by waist circumference (OR=0.993, P=0.012).

Conclusions

The serum omentin-1 level in adolescents is inversely associated with the aggregation of cardiovascular risk factors. Waist circumference and Body Mass Index are factors most closely associated with a decrease in the serum omentin-1 level.

Association between Circulating Omentin-1 Levels and Aortic Valve Sclerosis

BACKGROUND

Aortic valve sclerosis (AVS) is characterized by thickening of the valve leaflets accompanied by increased echogenicity and calcification without significant limitations in valve movements. Omentin-1 is a glycoprotein of the adiponectin family released from visceral adipose tissue, and it can be used as a biomarker of atherosclerosis, obesity, and metabolic syndrome. No studies have demonstrated any relationship between AVS and omentin-1 in the literature. We aimed to explore the association of serum omentin-1 levels with AVS.

METHODS

Eighty-six patients with AVS and 92 age- and sex-matched controls were enrolled into the study. The baseline clinical characteristics of the patients were recorded. Conventional 2-dimensional echocardiography was performed. Omentin-1 levels were measured.

RESULTS

The mean omentin-1 level was significantly lower in the AVS (+) group compared to the control group (78.16 ± 44.95 vs. 163.57 ± 59.84 ng/mL, p < 0.001). Omentin-1 [odds ratio (OR) = 3.45, 95% confidence interval (CI) = 1.88-5.39, p < 0.001,] and LDL-C (OR = 1.82, 95% CI = 1.33-2.16, p = 0.015) were found to be independent predictors of AVS in multivariate logistic regression analysis. An omentin-1 level of < 92.45 ng/mL had 90.5% sensitivity and 71.4% specificity for the prediction of AVS (area under curve: 0.697, p < 0.001).

CONCLUSIONS

Our results indicated that a lower omentin-1 level was associated with an increased risk of AVS. We suggest that omentin-1 could be used as a treatment target as well as to predict AVS.

Omentin-1 promoted proliferation and ameliorated inflammation, apoptosis, and degeneration in human nucleus pulposus cells

PURPOSE

Intervertebral disc degeneration is an abnormal, cell-mediated process of tissue remodeling, recognized as the principal cause of low back pain affecting 80% of the population worldwide. Inflammatory cytokine, Interleukin-1beta (IL-1β) is involved in the intervertebral disc degeneration (IDD) process, and it is upregulated in degenerated discs. Omentin-1, also known as intelectin-1, is an adipokine with anti-inflammatory, anti-apoptosis, pro-proliferation, and proangiogenic properties in various types of cells. However, little is known about the effects of omentin-1 on human nucleus pulposus cells (HNPCs). This study aims to investigate the effects of omentin-1 on healthy HNPCs regarding proliferation and further investigate the effects of omentin-1 on IL-1β-induced inflammation, apoptosis, and degeneration in HNPCs.

METHODS

Genes and proteins of interest were measured by qRT-PCR, immunoblotting, and immunofluorescence to conduct related experiments. Cell viability (CCK-8), EdU, and mitochondrial membrane potential (JC-1), flow cytometry assays were used to assess proliferation and apoptosis, respectively.

RESULTS

Our study showed that omentin-1 promoted proliferation in normal HNPCs. Furthermore, omentin-1 expression was decreased in IL-1β-treated HNPCs. Omentin-1 protected against IL-1β-induced inflammation, apoptosis, and degeneration in HNPCs in vitro via the activation of the PI3K/Akt signaling pathway.

CONCLUSION

These findings may contribute to understanding the role of omentin-1 in HNPCs and may be a potential therapeutic candidate for intervertebral disc degeneration.

Omentin-1 alleviate interleukin-1β(IL-1β)-induced nucleus pulposus cells senescence

One of the main causes of low back pain (LBP) and degenerative musculoskeletal disorders is intervertebral disc degeneration (IVDD). Inflammation-associated senescence of Human nucleus pulposus cells (HNPCs) plays an essential function in the disease progression of IVDD. Omentin-1 is an adipokine that has been recently reported to have anti-inflammatory potential. In our research, IL-1β was used to simulate the inflammatory environment in the IVDD. We investigated in vitro the effects of Omentin-1 on HNPCs, including the components of senescence, cell cycle and extracellular matrix (ECM) synthesis. The results showed that the addition of Omentin-1 improved IL-1β-induced senescence in HNPCs. G1 phase cell cycle arrest and reduced ECM synthesis in HNPCs. Furthermore, we demonstrated that the effect of Omentin-1 in reducing senescence of HNPCs is dependent on SIRT1. These findings suggest that Omentin-1 plays an important function in protecting HNPCs against senescence and has the potential for IVDD gene target therapy.

Circulating Omentin-1 levels and altered iron balance in chronic haemodialysis patients

Background

Iron deficiency is highly prevalent among patients undergoing chronic haemodialysis (HD) but its correct identification is often problematic as common biomarkers of iron status, such as transferrin saturation (TSAT) and ferritin, can be altered by inflammation or malnutrition.

Methods

In this pilot multicentre study, we aimed at evaluating circulating levels of Omentin-1, a novel fat depot-specific adipokine that is also involved in iron regulation, in a cohort of 85 chronic HD patients with relation to their iron status.

Results

Omentin-1 levels in HD were statistically higher than in healthy controls (P = 0.03) and there was a significant, growing trend in all iron parameters across Omentin-1 tertiles (P < 0.001). Compared with patients with optimal iron status, Omentin-1 levels were lower in subjects categorized according to TSAT ≤20% or serum ferritin ≤200 μg/L (both P < 0.001) and even more reduced in 19 patients (22%) simultaneously displaying low levels of both markers (P < 0.001). In this latter group, Omentin-1 levels increased in parallel to all other iron markers after iron correction by i.v. supplementation. At multivariate regression analyses, ferritin (β = 0.71; P < 0.001) and TSAT (β = 0.32; P = 0.03) remained the sole independent predictors of Omentin-1 levels. This biomarker also showed a remarkable diagnostic capacity at receiver operating characteristic analyses in identifying iron-depleted HD patients according to a criterion of TSAT ≤20% [area under the curve (AUC) 0.827], ferritin ≤200 μg/L (AUC 0.863) or low levels of both parameters (AUC 0.907).

Conclusions

Findings obtained indicate that Omentin-1 is somewhat involved in iron balance regulation and might be a candidate biomarker for diagnosing and managing altered iron conditions in HD patients.

Omentin-1: A newly discovered warrior against metabolic related diseases

INTRODUCTION

: Chronic metabolism-related diseases are challenging clinical problems. Omentin-1 is mainly expressed in stromal vascular cells of adipose tissue and can also be expressed in airway goblet cells, mesothelial cells, and vascular cells. Omentin-1 has been found to exert important anti-inflammatory, antioxidative and anti-apoptotic roles and to regulate endothelial dysfunction. Moreover, omentin-1 also has protective effects against cancer, atherosclerosis, type 2 diabetes mellitus, and bone metabolic diseases. The current review will discuss the therapeutic potential of omentin-1.

AREAS COVERED

: This review summarizes the biological actions of omentin-1 and provides an overview of omentin-1 in metabolic-related diseases. The relevant literature was derived from a PubMed search spanning 1998-2021 using these search terms: omentin-1, atherosclerosis, diabetes mellitus, bone, cancer, inflammation, and oxidative stress.

EXPERT OPINION

: As a novel adipocytokine, omentin-1 is a promising therapeutic target in metabolic-related diseases. Preclinical animal studies have shown encouraging results. Moreover, circulating omentin-1 has excellent potential as a noninvasive biomarker. In the future, strategies for regulating omentin-1 need to be investigated further in clinical trials in a large cohort.

Omentin-1 and its relationship with inflammatory factors in maternal plasma and visceral adipose tissue of women with gestational diabetes mellitus

PURPOSE

To investigate the association of omentin-1 and inflammatory factors in serum and visceral adipose tissue (VAT) of women with gestational diabetes mellitus (GDM) compared to normal pregnant (NP) subjects. Furthermore, to examine their correlation with maternal clinical characteristics.

METHODS

We compared 116 GDM women to 115 NP women, at the time of cesarean section. Circulating omentin-1 and pro-inflammatory (IL-1β, IL-6, TNF-α), and anti-inflammatory cytokines (IL-1RA, IL-10) were examined. Moreover, their mRNA expression in VAT, along with inflammatory factors involved in the NF-κB pathway (TLR2, TLR4, NF-κB, IKκB), were examined.

RESULTS

Circulating omentin-1 (p = 0.022) was lower and circulating IL-1-β, IL-1RA, as well as IL-10 (p = 0.005, p = 0.007, and p = 0.015, respectively), were higher in GDM compared to NP women. Omentin-1 correlated negatively with pre-pregnancy and gestational BMI, and HOMA-IR in all women, but was not associated with cytokines. TLR2, TLR4, IL-1β, IL-1RA, IL-6, IL-10 mRNA expression in VAT was lower in GDM compared with controls (p < 0.05 all). In multivariate analysis, BMI at delivery was significantly correlated to omentin-1 concentrations in all and NP subjects. In addition, omentin-1 expression was correlated to inflammatory gene expression in all, GDM and NP, women (p < 0.05 all).

CONCLUSION

Serum levels and VAT gene expression of omentin-1 are not independently linked to GDM; notwithstanding, GDM women have a VAT-altered inflammatory status. In addition, no systemic association between omentin-1 and inflammatory factors was found, whereas associations between their expression in all women were observed, indicating that expression of these adipokines is linked between them regardless of GDM.

Omentin-1 and diabetic foot

Introduction: Diabetic foot disease is an advanced complication of diabetes mellitus, which is associated with severe invalidization and high mortality rate among affected people. Many factors are involved in its pathogenesis but not all of them are fully elucidated. Objectives: Adipose tissue and its hormones - adipokines, are related to diabetic complications and metabolic disorders. Until now, there are limited data on their role in diabetic foot. The aim of this cross-sectional study is to determine the levels of the adipokine omentin-1 in people with and without diabetic foot disease and to look for its potential involvement in this complication. Methods: Eighty patients with type 2 diabetes and mean age of 60.8±10.5 years were included in this study. They were divided into two groups: with (n=36) and without (n=44) diabetic foot disease. Standard antrometric, clinical and laboratory tests were made. Body composition was analyzed by bioelectrical impedance based device. Serum omentin-1 was measured using ELISA method. Results: Levels of omentin-1 were significantly higher among people with diabetic foot disease (700.2±345.1 ng/ml), compared to the other group (560.2±176.7 ng/ml). This difference remained significant even after adjusting for potential confounders. In a regression model omentin-1 proved its predictive value for development of diabetic foot. Conclusion: Adipokines, and particularly omentin-1, might be included in the pathogenesis of diabetic foot disease.

Correlation of Serum Vaspin, Omentin-1, and adiponectin with metabolic phenotypes in Type-2 diabetes mellitus patients

Objectives:

To investigate adipocytokines’ (vaspin, omentin-1, and adiponectin) correlation with metabolic phenotypes in type 2 diabetes mellitus (T2DM) patients.

Methods:

This case-control research was done at the Diabetic Clinic in Jeddah, Kingdom of Saudi Arabia (KSA), from November 2018 to March 2019. Seventy-five T2DM patients and 75 gender, age, and BMI-matched healthy subjects were recruited for this research.

Results:

In DM patients, the concentrations of serum vaspin and omentin-1 were substantially lower (p<0.001) than in the control group. A significant positive relationship between vaspin concentration and DBP (p<0.001), BMI (p<0.001), and waist circumference (p<0.001) was found in patients and control subjects, while FPG (p<0.016), serum insulin (p<0.001), HOMA-IR (p<0.001), TC (p<0.001), TG (p<0.001), and LDLc (p<0.001) were significantly interrelated among patients. Serum concentrations of omentin-1 and ADN were significantly negatively correlated with serum insulin, HOMA-IR, and TG among the DM group. Serum vaspin and ADN levels were significantly higher in the cases and control groups with BMI>25, and no gender-wise variance was observed in adipocytokines levels. Binary logistic regression analysis showed a significantly negative predictive relationship of vaspin and omentin-1 with DM.

Conclusion:

The DM group displayed substantially lower serum vaspin and omentin-1 levels. However, there was no consistent relationship observed between these adipocytokines and metabolic phenotypes.

Deficiency of Omentin-1 leads to delayed fracture healing through excessive inflammation and reduced CD31hiEmcnhi vessels

Fracture healing is a complicated process affected by many factors, such as inflammatory responses and angiogenesis. Omentin-1 is an adipokine with anti-inflammatory properties, but whether omentin-1 affects the fracture healing process is still unknown. Here, by using global omentin-1 knockout (omentin-1^-/-) mice, we demonstrated that omentin-1 deficiency resulted in delayed fracture healing in mice, accompanied by increased inflammation and osteoclast formation, and decreased production of platelet-derived growth factor-BB (PDGF-BB) and osteogenesis-promoting vessels that are strongly positive for CD31 and Endomucin (CD31^hiEmcn^hi) in the fracture area. In vitro, omentin-1 treatment suppressed the ability of the tumor necrosis factor-α (TNF-α)-activated macrophages to stimulate multi-nuclear osteoclast formation, resulting in a significant increase in the generation of mono-nuclear preosteoclasts and PDGF-BB, a pro-angiogenic protein that is abundantly secreted by preosteoclasts. PDGF-BB significantly augmented endothelial cell proliferation, tube formation and migration, whereas direct treatment with omentin-1 did not induce obvious effects on angiogenesis activities of endothelial cells. Our study suggests a positive role of omentin-1 in fracture healing, which may be associated with the inhibition of inflammation and stimulation of preosteoclast PDGF-BB-mediated promotion of CD31^hiEmcn^hi vessel formation.

Expression of adipokines in children with primary nephrotic syndrome and its association with hyperlipidemia

OBJECTIVES

To study the expression of adipokines in children with primary nephrotic syndrome (PNS) before and after treatment and its correlation with blood lipids, as well as the role of adipokines in PNS children with hyperlipidemia.

METHODS

A total of 90 children who were diagnosed with incipient PNS or recurrence of PNS after corticosteroid withdrawal for more than 6 months were enrolled as subjects. Thirty children who underwent physical examination were enrolled as the control group. Venous blood samples were collected from the children in the control group and the children with PNS before corticosteroid therapy (active stage) and after urinary protein clearance following 4 weeks of corticosteroid therapy (remission stage). ELISA was used to measure the levels of adipokines. An automatic biochemical analyzer was used to measure blood lipid levels.

RESULTS

Compared with the control group, the children with PNS had a significantly lower level of omentin-1 in both active and remission stages, and their level of omentin-1 in the active stage was significantly lower than that in the remission stage (P<0.001). For the children with PNS, the level of chemerin in the active stage was significantly higher than that in the remission stage, and the children with PNS in the active stage had a significantly higher level of chemerin than the control group (P<0.001). For the children with PNS, atherogenic index of plasma, atherogenic coefficient (AC), castelli risk index-1 (CRI-1), castelli risk index-2 (CRI-2), and non-high-density lipoprotein in the active stage were significantly higher than those in the remission stage (P<0.001), and these indices in the children with PNS in the active stage were significantly higher than those in the control group (P<0.001). The children with PNS in the remission stage had significantly higher atherogenic index of plasma, AC, CRI-1, and non-high-density lipoprotein than the control group (P<0.001). Compared with the control group, the children with PNS in the remission stage had significantly higher serum levels of total cholesterol, triglyceride, high-density lipoprotein, low-density lipoprotein, apolipoprotein B, and apolipoprotein A (P<0.01). In the children with PNS, the ratio of omentin-1 before and after corticosteroid therapy was positively correlated with that of high-density lipoprotein, 24-hour urinary protein excretion, and high-density lipoprotein/apolipoprotein A before and after treatment, and it was negatively correlated with the ratio of AC and CRI-1 before and after treatment (P<0.05). The PNS children with low omentin-1 levels in the active stage had significantly higher levels of CRI-1, CRI-2, AC, and apolipoprotein B/apolipoprotein A ratio than those with high omentin-1 levels (P<0.05).

CONCLUSIONS

Omentin-1 may be associated with disease activity, dyslipidemia, and proteinuria in children with PNS. Blood lipid ratios may be more effective than traditional blood lipid parameters in monitoring early cardiovascular risk in children with PNS.

Association between the omentin-1 gene rs2274907 A>T polymorphism and colorectal cancer in the Chinese Han population: a case-control study

OBJECTIVE

To explore the relationship between the omentin-1 gene rs2274907 A>T polymorphism and colorectal cancer (CRC) in the Chinese Han population.

METHODS

rs2274907 A>T was assessed by PCR-restriction fragment length polymorphism analysis. Plasma omentin-1 expression from 358 patients with CRC and 286 healthy controls was analyzed by enzyme-linked immunosorbent assay. CRC and control groups were divided into subgroups according to the body mass index (BMI) threshold of 25 kg/m².

RESULTS

No significant differences were observed between CRC and control groups in terms of genotype or allele frequencies of rs2274907 A>T. Compared with individuals with BMI <25 kg/m² and the rs2274907 TT genotype, those with AA+AT genotypes and BMI ≥25 kg/m² had a 3.027-fold increased risk of CRC. A significant tendency toward a higher stage of colorectal adenocarcinomas and depth of invasion was observed in individuals with the rs2274907 AA genotype compared with other genotypes.

CONCLUSIONS

The omentin-1 gene rs2274907 A>T polymorphism does not seem to play a critical role in the development of CRC in the Chinese Han population, but an interaction between the rs2274907 A allele and BMI may increase the CRC risk. The rs2274907 AA genotype is a potential biomarker for CRC stage progression.

Associations of dietary fats intake and adipokines levels in obese women

AIM

RBP4, Vaspin and omentin-1 are adipokines, which play an important role in the development of obesity-related complications. The main aim of this study was to investigate the effects of different kinds of fat intake on adipokine levels in obese women.

METHODS

A total of 272 obese women (BMI ≥ 30) were included in the current cross-sectional study, according to the inclusion and exclusion criteria. Body composition was measured using a body composition analyzer. For the measurement of retinol binding protein 4 (RBP4), vaspin and omentin-1 serum concentrations, an enzyme-linked immunosorbent assay (ELISA) method was used. Dietary intake was assessed using a 3-day 24-h dietary recall.

RESULTS

Statistically significant differences were found between polyunsaturated fatty acid (PUFAs) and linoleic acid intake and vaspin and omentin-1 levels. In addition, there were found statistically significant relationships between cholesterol, monounsaturated fatty acid (MUFAs) and total fat intakes with omentin-1 levels. Also, RBP4 and vaspin levels were different significant with eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake. Moreover, the results revealed that there were statistically significant differences between RBP4 levels and α-linolenic acid and oleic acid intake.

CONCLUSION

This study revealed that by examining RBP4, vaspin and omentin-1 as adipokines, a novel link between fat intakes and adipokine levels was found.

Tetrahydroxystilbene glycoside improves endothelial dysfunction and hypertension in obese rats: The role of omentin-1

RATIONALE

Hypertension in obesity has become a major threat for public health. Omentin-1, a novel adipokine, is down-regulated in obesity. Tetrahydroxystilbene glycoside (TSG) is the main ingredient extracted from Polygonum multiflorum Thunb (PMT), a traditional Chinese medicinal herb safely used for protecting cardiovascular systems over bimillennium. This study aims to examine (i) the impact of omentin-1 downregulation on obesity-related hypertension in murine models and the underlying mechanisms; (ii) whether tetrahydroxystilbene glycoside (TSG) improved endothelial dysfunction and obesity-associated hypertension via the increase of omentin-1.

METHODS

(TSG-treated) male Zucker diabetic fatty (ZDF) rats and omentin-1 knockout (OMT^-/-) mice were used. In vitro, human umbilical vein endothelial cells (HUVECs) and mature adipocytes differentiated from human visceral preadipocyte (HPA-v) were maintained in a co-culture system.

RESULTS

TSG was the main active component of PMT reducing systolic blood pressure and improving endothelial vasodilation. Fortnight-TSG treatment (100 mg/kg/day) increased serum omentin-1 level, also activated Akt/eNOS signaling and enhanced NO bioactivity; decreased expression of NOX2 and p22^phox, suppressed production of superoxide and peroxynitrite anion. OMT^-/- mice showed elevated blood pressure and impaired endothelial vasorelaxation, whereas hypotensive effect of TSG was blunted. In co-culture system, TSG incubation promoted binding of peroxisome proliferator-activated receptor-γ (PPAR-γ) and Itln-1 promoter in adipocytes, activated Akt/eNOS/NO signaling and attenuated oxidative/nitrative stress in HUVECs. Suppression of Itln-1 with siRNA significantly blocked the protective effect of TSG in vitro.

CONCLUSIONS

Down-regulation of omentin-1 induces endothelial dysfunction and hypertension in obesity. TSG treatment (at least partially) increases omentin-1 via promoting binding of PPAR-γ and Itln-1 promoter in adipose tissues, subsequently exerts protective effects on endothelial function via activating Akt/eNOS/NO signaling and attenuating oxidative/nitrative stress. These results suggest that TSG could be developed as a promising anti-hypertension agent that protects against endothelial dysfunction and obesity-associated cardiovascular diseases.

Omentin-1: Protective impact on ischemic stroke via ameliorating atherosclerosis

Omentin-1, a newly identified adipokine, has recently been revealed as a novel biomarker for ischemic stroke (IS). Low circulating omentin-1 levels could indicate a high risk of IS, and elevated omentin-1 levels exert a favorable impact on cerebral ischemia. Furthermore, omentin-1 has anti-atherosclerotic, anti-inflammatory, and cardiovascular protective capabilities through the intracellular Akt/AMP-activated protein kinase (AMPK)/ nuclear factor-κB (NF-κB) and certain protein kinase (ERK, JNK, and p38) signaling pathways. Omentin-1 also alleviates endothelial cell dysfunction, improves revascularization via the Akt-endothelial nitric-oxide synthase (eNOS) regulatory axis, promotes endothelium-dependent vasodilation through endothelium-derived NO in an eNOS fashion, and inhibits VSMC proliferation by means of AMPK/ERK signaling pathways, VSMC migration via inactivation of the NADPH oxidase (NOX)/ROS/p38/HSP27 pathways and artery calcification via the PI3K-Akt pathway. These findings indicate that omentin-1 may be a negative mediator of IS. Pharmacologically, several lines of clinical evidence indicate that metformin and statins could elevate omentin-1 levels, although the specific mechanism has not been precisely delineated until now. This study is the first to summarize the comprehensive mechanisms between omentin-1 and atherosclerosis and to review the shielding effect of omentin-1 on IS. We shed light on omentin-1 as a novel therapeutic target for combating IS.

Study on Omentin-1 and miR-502-3p in osteoporotic fracture

OBJECTIVES

To explore the expression and correlation of Omentin-1 and miR-502-3p in serum of patients with osteoporotic fracture (OPF).

METHODS

Sixty OPF patients diagnosed and treated in our hospital from June 2018 to December 2019 were included in group A. Fifty-six osteoporosis patients without fractures were included in group B. Omentin-1 and miR-502-3p levels were detected by enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR (qRT-PCR). Their predictive value for diagnostic efficiency was assessed by ROC curve. Spearman's rank correlation test was used for correlation analysis. The risk factors related to the prognosis of OPF were analyzed by Logistic univariate and multivariate analysis.

RESULTS

The expression of Omentin-1 and miR-502-3p in group A was markedly lower than in group B (P<0.001). Spearman correlation analysis showed that in OPF, there was a negative correlation between serum Omentin-1 and TNF-α (r=0.8579, P<0.001), a negative correlation between serum miR-502-3p and TNF-α (r= 0.8653, P<0.001), and a positive correlation between serum Omentin-1 and miR-502-3p (r= 0.8764, P<0.001).

CONCLUSIONS

Omentin-1 and miR-502-3p were down-regulated in serum of patients with OPF, both of which could be used as potential biomarkers for the diagnosis and disease evaluation of OPF.

Omentin: A novel therapeutic approach for the treatment of endothelial dysfunction in type 2 diabetes

BACKGROUND

Perivascular adipose tissue (PVAT) locally influences the functioning of blood vessels and promotes vascular complications associated with diabetes and obesity. The aim of this work was to study the impact of omentin-1 on endothelial function and PVAT in a non-obese type 2 diabetes mellitus animal model, Goto-Kakizaki (GK) rats with or without high fat diet.

MATERIAL AND METHODS

Diabetic GK rats were divided into four groups: 1) control group; 2) group treated with omentin-1; 3) group of GK rats fed a high fat diet (GKHFD) and 4) group of GKHFD treated with omentin-1. Several in vivo parameters such as adiposity and Lee indexes, lipid profile, fasting glucose levels, glucose and insulin tolerance tests were determined. At the vascular level, endothelial dependent and independent relaxation and contraction studies were performed in aortic rings in the absence (PVAT-) or in the presence (PVAT+) of thoracic PVAT. We also evaluated vascular oxidative stress and determined the pro-inflammatory status of PVAT.

RESULTS

Endothelium-dependent relaxation to acetylcholine, assessed by wire myography, was impaired in GK and GKHFD rats and improved by the omentin-1 treatment. In addition, vascular superoxide production was increased in the vascular wall of diabetic rats, accompanied by reduced nitric oxide bioavailability and significantly improved by omentin treatment. PVAT anti-contractile action found under physiological conditions was lost in type 2 diabetes, and partially recovered with omentin-1 administration. In addition, omentin-1 treatment significantly improved proinflammatory and pro-oxidant PVAT phenotype (decreasing C-reactive protein and nitrotyrosine levels). Furthermore, it was observed an improvement in various systemic and metabolic biochemical parameters of diabetic animals treated for one month with omentin.

CONCLUSIONS

Omentin-1 ameliorates endothelial dysfunction in type 2 diabetes and presents therapeutic potential for the treatment of vascular complications associated with type 2 diabetes.

Omentin-1 and vaspin serum levels in patients with pre-clinical carotid atherosclerosis and the effect of statin therapy on them

BACKGROUND

Omentin-1 and vaspin are novel adipokines, and their association with atherosclerosis is still under investigation. The present study aimed to assess the relationship of those adipokines with preclinical, non-significant carotid atherosclerosis and the impact of statin therapy on their levels, suggesting a link between adiposity and atherosclerosis.

METHODS

Eighty-four statin-free subjects with non-significant, preclinical carotid atherosclerosis and elevated LDL- cholesterol levels (>130 mg/dl) were recruited to receive atorvastatin (from 10 to 80 mg per day) (atorvastatin group - AG group). Forty-six age- and gender-matched healthy individuals, without any chronic disease served as controls (control group - CG). Clinical parameters, metabolic profile, serum omentin-1, vaspin concentrations and ultrasound measurements of carotid thickening were obtained at the beginning and after 12 months.

RESULTS

At baseline, AG showed lower omentin-1 and vaspin serum levels than CG (p ≤ 0.001). Along the entire study population at baseline, omentin-1 levels were independently related to LDL-cholesterol, while vaspin levels were independently associated with hsCRP and the presence of carotid atherosclerosis (p < 0.05). Within AG, 12-months atorvastatin treatment significantly increased omentin-1 (from 202.79 ± 91.41 ng/ml to 262.56 ± 101 ng/ml, p < 0.001) and vaspin concentrations (from 1.29 ± 0.51 ng/ml to 1.70 ± 0.5 ng/ml, p = 0.002). In standard multiple regression analysis, the presence of carotid atherosclerosis related to baseline vaspin levels (β = -0.232, p < 0.001), while the atorvastatin-induced increase of vaspin was independently associated with hsCRP reduction (β = -0.198, p = 0.045).

CONCLUSION

Low omentin-1 and vaspin serum levels associated with preclinical, non-significant carotid atherosclerosis. Notably, atorvastatin administration significantly increased both adipokines, but the underlying mechanisms and the clinical impact of those changes requires further investigation.

Evaluation of adipokines, adiponectin, visfatin, and omentin, in uncomplicated type I diabetes patients before and after treatment of diabetic ketoacidosis

BACKGROUND

Diabetic ketoacidosis (DKA) is potentially a lethal complication of uncontrolled, especially type 1, diabetes. Understanding the mechanisms underlying adipokine involvement in the regulation of glucose metabolism is important to prevent complications of hyperglycemia. The role of novel adipokines during DKA in human remains unclear.

METHOD

The method is to determine the changes in the circulating levels of adiponectin, visfatin, and omentin after treating DKA in the patients referred to Shohadaye Khalij-e-Fars hospital at the Bushehr University of Medical Sciences. Measuring adipokines (adiponectin, visfatin, and omentin) in 31 patients with DKA who are admitted in Shohadaye Khalij-e-Fars hospital at the Bushehr University of Medical Sciences. Adipokines are measured at the time of admission and after recovery from DKA, using ELISA method.

RESULTS

After recovery from DKA, omentin-1 serum concentration decreased significantly (from 183 to 165), but adiponectin and visfatin did not change significantly.

CONCLUSION

Omentin-1 may play a significant role in insulin resistance during the DKA and could be potentially recommended as a marker of recovery in DKA.

Association between omentin-1 and major cardiovascular events after lower extremity endovascular revascularization in diabetic patients: a prospective cohort study

Background

Cardiovascular complications represent the major cause of morbidity and mortality of type 2 diabetes mellitus (T2DM) patients. In particular, peripheral artery disease (PAD) represents a frequent T2DM vascular complication and a risk factor for the development of major adverse cardiovascular events (MACE). Among adipokines, omentin-1 serum levels are reduced in T2DM patients with PAD and are inversely related to disease severity.

Objective

To study the relationship between omentin-1 levels, at baseline, with outcomes after endovascular procedures in T2DM patients with PAD and chronic limb-threatening ischemia (CLTI).

Research design and methods

We enrolled for our prospective non-randomized study, 207 T2DM patients with PAD and CLTI, requiring revascularization. Omentin-1 serum levels were collected before revascularization and patients incidence outcomes were evaluated at 1, 3, 6 and 12 months.

Results

Omentin-1 was reduced in patients with more severe disease (27.24 ± 4.83 vs 30.82 ± 5.48 ng/mL, p < 0.001). Overall, 84 MACE and 96 major adverse limb events (MALE) occurred during the 12-month follow-up. We observed that omentin-1 levels were lower in patients with MACE (26.02 ± 4.05 vs 31.33 ± 5.29 ng/mL, p < 0.001) and MALE (26.67 ± 4.21 vs 31.34 ± 5.54 ng/mL, p < 0.001). The association between omentin-1, MACE and MALE remained significant after adjusting for major risk factors in a multivariate analysis. Receiver operating characteristics (ROC) curve using omentin-1 levels predicted incidence events (area under the curve = 0.80).

Conclusions

We demonstrated that reduced omentin-1 levels, at baseline, are related with worse vascular outcomes in T2DM patients with PAD and CLTI undergoing an endovascular procedure.

Analysis of the expression of plasma omentin-1 level in colorectal cancer and its correlation with prognosis

BACKGROUND

Colorectal cancer (CRC) is a malignant tumor of the digestive tract, with high incidence and mortality. This study aims to investigate the expression of plasma omentin-1 level in patients with CRC and its correlation with the prognosis of patients.

METHODS

Clinical data of 319 patients (case group) who underwent radical resection of CRC in our hospital from June 2015 to March 2018 were collected, simultaneously, 300 people without the apparent physical disease who underwent physical examination in our hospital during the same period were randomly selected as the control group, plasma omentin-1 levels in the two groups were compared by T-test. Cancer patients were followed up, and multi-factor COX regression analysis was used to analyze the factors affecting patients' recurrence and survival.

RESULTS

The level of plasma omentin-1 in patients with colorectal cancer is closely related to TNM staging and lymph node metastasis. The CRC case group was significantly reduced after surgery, but it was still higher than that in the control group (P<0.05). At the end of the follow-up, 28 cases were lost to follow-up, and 291 cases (91.22%) were effectively followed up. During the follow-up period, the recurrence and metastasis rate was 30.58% (89/291), and the mortality rate was 19.26% (56/291). According to the multi-factor analysis, the risk factors for the recurrence of CRC patients were TNM stage III-IV (OR =1.978, 95% CI: 1.088-3.596), lymph node metastasis (OR =2.073, 95% CI: 1.179-3.645) and omentin-1 level ≥50 ng/mL (OR =3.347, 95% CI: 1.416-7.912). The risk factors for the survival of patients with CRC were poorly differentiated (OR =1.960, 95% CI: 0.985-3.900), lymph node metastasis (OR =2.452, 95% CI: 1.213-4.956), vascular carcinoma thrombus (OR =2.026, 95% CI: 1.036-3.960) and omentin-1 level ≥50 ng/mL (OR =2.067, 95% CI: 1.013-4.218).

CONCLUSIONS

The level of plasma omentin-1 is highly expressed in patients with CRC, an independent risk factor for the recurrence and survival of patients.

Effects of Probiotic Yogurt on Serum Omentin-1, Adropin, and Nesfatin-1 Concentrations in Overweight and Obese Participants Under Low-Calorie Diet

Data on the effects of probiotics on adipokines such as omentin-1, nesfatin-1, and adropin are limited. The aim of this study was to evaluate the effects of probiotic yogurt along with a low-calorie diet (LCD) on serum omentin-1, adropin, and nesfatin-1 concentrations in obese and overweight individuals. Sixty obese or overweight individuals aged 20-50 years old were involved in this randomized double-blind placebo-controlled clinical trial. Participants were randomly allocated into two groups to consume either probiotic yogurt containing Lactobacillus acidophilus La5, Bifidobacterium BB12, and Lactobacillus casei DN001 (10⁸ CFU/g each) (n = 30) or regular yogurt (n = 30) along with a LCD in both groups for 8 weeks. Fasting blood samples were taken at baseline and after the 8-week intervention to determine related variables. A significant decrease in body fat percentage was observed in the probiotic group compared with the regular group after 8 weeks (- 1.51 ± 069 vs - 0.88 ± 0.68%, P = 0.002). After the 8-week intervention, a significant difference in serum adropin concentration (6.04 ± 24.46 vs - 8.16 ± 24.66 pg/ml, P = 0.03 and serum omentin-1 concentration (0.09 ± 1.51 vs - 1.5 ± 1.8 ng/ml, P = 0.003) was observed between two groups. We did not observe any significant changes in nesfatin-1 and other anthropometric measures. Overall, probiotic yogurt for 8 weeks among overweight or obese individuals along with LCD had beneficial effects on body fat percentage, serum omentin-1, and adropin concentration, but it did not have any effect on nesfatin-1 level.

The protective role of omentin-1 in IL-1β-induced chondrocyte senescence

Osteoarthritis is a common type of degenerative joint disease. Inflammation-related chondrocyte senescence plays a major role in the pathogenesis of osteoarthritis. Omentin-1 is a newly identified anti-inflammatory adipokine involved in lipid metabolism. In this study, we examined the biological function of omentin-1 in cultured chondrocytes. The presence of omentin-1 potently suppresses IL-1β-induced cellular senescence as revealed by staining with senescence-associated beta-galactosidase (SA-β-Gal). At the cellular level, omentin-1 attenuates IL-1β-induced G1 phase cell-cycle arrest. Mechanistically, we demonstrate that omentin-1 reduced IL-1β-induced expression of senescent factors including caveolin-1, p21, and PAI-1 as well as p53 acetylation through ameliorating SIRT1 reduction. Notably, silencing of SIRT1 abolishes IL-1β-induced senescence along with the induction of p21 and PAI-1, suggesting that the action of omentin-1 in chondrocytes is dependent on SIRT1. Collectively, our results revealed the molecular mechanism through which the adipokine omentin-1 exerts a beneficial effect, thereby protecting chondrocytes from senescence. Thus, omentin-1 could have clinical implication in the treatment of osteoarthritis.

Omentin-1 is associated with atrial fibrillation in patients with cardiac valve disease

BACKGROUND

Epicardial adipose tissue (EAT) remodeling and adipocytokines are associated with structural remodeling in atrial fibrillation (AF). However, the role of omentin-1, a novel adipocytokine, in structural remodeling remains unknown.

METHODS

Hematoxylin and eosin (H&E) and Masson's trichrome stains were used to investigate the histology of EAT and right atrial appendages. The expression levels of adipocytokines in these human samples were determined by immunohistochemical assay and western blotting. Models of transforming growth factor (TGF)-β1-induced activation of cardiac fibroblasts (CFs) and TGF-β1-induced endothelial-mesenchymal transition (EndMT) of human umbilical vein endothelial cell (HUVEC) were established to explore roles of omentin-1 in these processes. To determine changes in adipocytokines secretion under hypoxia conditions, adipocytes were treated with 5% O₂ and 95% N₂, and then CFs and HUVECs were co-cultured with the conditioned medium of adipocytes to determine the effects of hypoxia-treated adipocytes on these cells.

RESULTS

Expression of omentin-1 was downregulated in the EAT and right atrial appendages from patients with AF compared to samples from patients without AF, while the TGF-β1 level was upregulated in EAT from patients with AF. EAT from patients with AF exhibited adipocyte hypertrophy and severe interstitial fibrosis. Omentin-1 inhibited TGF-β1-induced CF activation and reversed TGF-β1-induced HUVEC EndMT. Adipocytes treated with hypoxia exhibited downregulation of omentin-1 and partly activated CFs.

CONCLUSIONS

This study demonstrated that omentin-1 was an antifibrotic adipocytokine and was downregulated in patients with AF, which was partly mediated by hypoxia.

Association of omentin-1, adiponectin, and resistin genetic polymorphisms with systemic lupus erythematosus in a Chinese population

OBJECTIVE

An increasing number of studies have demonstrated the roles of adipokines in systemic lupus erythematosus (SLE). We aimed to investigate the association of genetic variations of omentin-1, adiponectin, and resistin with SLE susceptibility.

METHODS

We selected 623 SLE patients and 665 normal controls in the present study. Genotyping of omentin-1 rs2274907, rs35779394, rs79209815, and rs13376023; adiponectin rs16861194 and rs266729; and resistin rs1862513, rs3745368, and rs3745367 was conducted by TaqMan SNP genotyping assays.

RESULTS

Overall, we found no significant differences in the allele or genotype frequencies of the nine studied SNPs between the SLE patients and controls. However, an increased frequency of the resistin rs3745368 variant was observed in the SLE patients under the dominant model (P = 0.024). In omentin-1, the rs13376023 A allele was found to be related to oral ulcers in SLE patients (P = 0.013), and the rs35779394 C and rs13376023 A allele frequencies were significantly lower in SLE patients with BMI ≥ 24 kg/m² (P = 0.019, P = 0.033, respectively). For resistin, the frequencies of the rs3745368 AA genotype and A allele were lower in SLE patients with discoid rash (P = 0.036, P = 0.011), and the rs3745368 A allele frequency was higher in SLE patients with lupus nephritis (P = 0.018). The resistin rs3745367 AA genotype and A allele frequencies were related to the occurrence of renal disorder in SLE patients (P = 0.024, P = 0.009). The haplotype analysis showed that the CGA haplotype of resistin was associated with susceptibility to SLE (P = 0.005). No significant associations of plasma omentin-1, adiponectin or resistin levels with their respective genotypes were found in SLE patients.

CONCLUSIONS

In summary, omentin-1, adiponectin and resistin SNPs are not associated with the genetic background of SLE in Chinese patients. However, omentin-1 and resistin genetic variations might contribute to several clinical phenotypes of SLE.

Serum omentin-1 and risk of one-year mortality in patients with ischemic stroke

BACKGROUND

Prior studies suggested that ischemic stroke patients with high omentin-1 concentrations were at a decreased risk of unstable carotid plaque and 3-month poor functional outcome. We aim to evaluate the association between serum omentin-1 and 1-y mortality after ischemic stroke.

METHODS

A total of 303 ischemic stroke patients were prospectively followed up at 1 y. Outcome was defined as death occurred during the follow-up period. A multivariable Cox model was used to evaluate the association between serum omentin-1 concentrations and 1-y mortality among ischemic stroke patients.

RESULTS

From lowest to highest tertile of serum omentin-1, the 1-y cumulative death rate was 12%, 3.7% and 2.1%, respectively (P = 0.006). The hazard ratio (95% confidence interval) of the highest tertile compared with the lowest tertile was 0.19 (0.04-0.88) for mortality after multivariable adjustment (P for trend < 0.01). The net reclassification index and integrated discrimination improvement were significantly improved in predicting 1-y mortality when omentin-1 data was added to the multivariable Cox regression model.

CONCLUSIONS

Among patients with ischemic stroke, high baseline serum omentin-1 was associated with a decreased risk of 1-y mortality. These findings, if confirmed by clinical trials, suggest that increasing omentin-1 concentrations may lower the risk of mortality among ischemic stroke patients.

Maternal omentin-1 level, quality of life and marital satisfaction in relation to mode of delivery: a prospective cohort study

Background

The purpose of this study was to evaluate the maternal omentin-1 level, quality of life and marital satisfaction of women with cesarean and vaginal delivery.

Methods

This prospective cohort study was conducted on 45 women with elective cesarean delivery and 45 women with vaginal delivery who referred to a public hospital in Tehran, Iran. Maternal omentin-1 level was measured by ELISA kits within 24 h after delivery. The maternal quality of life and marital satisfaction in the third trimester of pregnancy and at 12 weeks postpartum were measured using WHOQOL-BREF and the Kansas marital satisfaction questionnaires, respectively. For making between-groups and within-groups comparison, independent samples t-test, paired samples t-test and chi-square test were applied accordingly.

Results

The level of maternal omentin-1 was reported to be higher in vaginal delivery group compared to the cesarean group (p = 0.02). No significant difference was found in the quality of life between the two groups in the third trimester of pregnancy and at 12 weeks postpartum period. However, women in both groups had lower scores in physical dimension at 12 weeks postpartum compared to the third trimester of their pregnancy [mean ± SD in vaginal group = 59.28 ± 15.5 vs. 64.44 ± 15.05, p = 0.003 and mean ± SD in cesarean group = 60.07 ± 14.84 vs. 66.50 ± 11.32, p <  0.001]. The results of paired samples t-test indicated that women in NVD group had significantly higher psychological wellbeing at 12 weeks postpartum compared to the third trimester of pregnancy [mean ± SD 68.9 ± 16.82 vs. 65.73 ± 16.87, p = 0.001]. There was no significant difference in marital satisfaction between the two groups at 12 weeks postpartum (P = 0.07). The results of paired samples t-test showed that women in CS group had significantly lower marital satisfaction at 12 weeks postpartum compared to the third trimester of pregnancy [mean SD 18.86 ± 2.04 vs. 19.28 ± 1.79, p = 0.01].

Conclusions

Our findings demonstrated that women with NVD had higher omentin-1 level than women with CS. No significant difference was found in quality of life and marital satisfaction between NVD and CS and omentin-1 level. High level of omentin-1 in NVD may act as a protective factor for mother against metabolic disorders.

Insight into adipokines to optimize therapeutic effects of stem cell for tissue regeneration

Stem cell therapy is considered as a promising regenerative medicine for repairing and treating damaged tissues and/or preventing various diseases. But there are still some obstacles such as low cell migration, poor stem cell engraftment and decreased cell survival that need to be overcome before transplantation. Therefore, a large body of studies has focused on improving the efficiency of stem cell therapy. For instance, preconditioning of stem cells has emerged as an effective strategy to reinforce therapeutic efficacy. Adipokines are signaling molecules, secreted by adipose tissue, which regulate a variety of biological processes in adipose tissue and other organs including the brain, liver, and muscle. In this review article, we shed light on the biological effects of some adipokines including apelin, oncostatin M, omentin-1 and vaspin on stem cell therapy and the most recent preclinical advances in our understanding of how these functions ameliorate stem cell therapy outcome.

Omentin-1 protects against high glucose-induced endothelial dysfunction via the AMPK/PPARδ signaling pathway

High glucose-induced endothelial dysfunction is a critical initiating factor in the development of diabetic vascular complications. Omentin-1 has been regarded as a novel biomarker of endothelial function in subjects with type-2 diabetes (T2D); however, it is unclear whether omentin-1 has any direct effect in ameliorating high glucose-induced endothelial dysfunction. In the present study, we analyzed the effect of omentin-1 on high glucose-induced endothelial dysfunction in isolated mouse aortas and mouse aortic endothelial cells (MAECs). Vascular reactivity in aortas was measured using wire myography. The expression levels of AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor δ (PPARδ), Akt, endothelial nitric-oxide synthase (eNOS), and endoplasmic reticulum (ER)-stress markers in MAECs were determined by Western blotting. The production of reactive oxygen species (ROS) and nitric oxide (NO) was assessed by diluted fluoroprobe, 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) and 4-amino-5-methylamino-2',7'-difluorofluorescein (DAF-FM DA), respectively. We found that ex vivo treatment with omentin-1 reversed impaired endothelial-dependent relaxations (EDR) in mouse aortas after high-glucose insult. Elevated ER-stress markers, oxidative stress, and reduction of NO production induced by high glucose in MAECs were reversed by omentin-1 treatment. Omentin-1 also effectively reversed tunicamycin-induced ER stress responses in MAECs, as well as ameliorated impairment of endothelial-dependent relaxation in mouse aortas. Moreover, omentin-1 increased AMPK phosphorylation with a subsequent increase in PPARδ expression, while also restoring the decreased phosphorylation of Akt and eNOS. The effects of omentin-1 were abolished by cotreatment of compound C (AMPK inhibitor) and GSK0660 (PPARδ antagonist). These data indicate that omentin-1 protects against high glucose-induced vascular-endothelial dysfunction through inhibiting ER stress and oxidative stress and increasing NO production via activation of AMPK/PPARδ pathway.

Impact of serum omentin-1 concentrations on functional outcome among acute intracerebral hemorrhage patients

BACKGROUND

Reduced serum omentin-1 concentrations might be related to an increased risk for poor functional outcome after acute ischemic stroke. We intended to explore whether serum omentin-1 could be a promising prognostic biomarker for acute intracerebral hemorrhage.

METHODS

A total of 104 consecutive patients with hemorrhagic stroke underwent 90-day follow-up. The modified Rankin scale score >2 was evaluated as worse prognosis. A multivariable logistic model was conFig.d for assessing the relationship between serum omentin-1 concentrations and functional outcome.

RESULTS

Serum omentin-1 concentrations, with the median value of 147.9 ng/ml (interquartile range, 114.7-199.8 ng/ml), were substantially declined with rising modified Rankin scale scores (P < 0.001). Serum omentin-1 concentrations <147.9 ng/ml was independently related to higher risk of 90-day worse prognosis (odds ratio, 3.789; 95% confidence interval, 1.819-8.608; P = 0.018). Under receiver operating characteristic curve, an optimal value of serum omentin-1 concentrations was selected as 179.7 ng/ml, which yielded 0.88 sensitivity value and 0.70 specificity value for discriminating patients at risk of 90-day worse prognosis (area under curve, 0.82; 95% confidence interval, 0.73-0.89).

CONCLUSIONS

Lower serum omentin-1 concentrations are closely associated with poor functional outcome after hemorrhagic stroke, substantializing serum omentin-1 as a potential prognostic biomarker for acute intracerebral hemorrhage.

New Biomarkers as Prognostic Factors for Cardiovascular Complications in Type 2 Diabetic Patients

This study was initiated to explore some novel biomarkers like pro-inflammatory markers (chemerin and visfatin) and anti-inflammatory marker (omentin-1) as prognostic factors for cardiovascular complications in type 2 diabetic patients. Forty diabetic patients without cardiovascular disease, 40 diabetic patients with cardiovascular disease and twenty healthy control counterparts were included in this study. Serum chemerin, omentin-1 and visfatin levels were quantified. Receiver operating characteristic curve analysis was done to identify the cut off value for each marker. The mean serum level of chemerin was 57.65 ± 15.69 ng/l in diabetic patients versus 93.97 ± 26.62 ng/l for the cardio-diabetic ones (P < 0.0001). The mean serum level of omentin-1 was 8.77 ± 1.53 ng/ml in diabetic patients versus 1.76 ± 0.96 ng/ml for the cardio-diabetic ones (P < 0.0001). The mean level of visfatin was 1.44 ± 0.71 ug/l in diabetic patients versus 3.92 ± 3.32 ug/l for the cardio-diabetic ones (P < 0.0001). Chemerin and Visfatin levels were significantly enhanced in the cardio-diabetic patients with increasing C-reactive protein (CRP), triglycerides (TG), fasting blood glucose (FBG), micro-albumin and cholesterol. Omentin-1 level was significantly reduced in the cardio-diabetic patients with increasing CRP, TG, FBG, and cholesterol. It was observed that the area under curve for chemerin, omentin-1and visfatin was 0.877, 0.998 and 0.735, respectively. In conclusion, this study evidences that the measuring serum levels of chemerin, omentin-1 and visfatin may help in the prognosis of cardiovascular complications in type 2 diabetic patients.

Association of Omentin-1 with Oxidative Stress and Clinical Significances in Patients with Breast Cancer

Purpose: Breast cancer (BC) is globally the main reason of cancer-related deaths in women. Omentin-1, an anti-inflammatory and antioxidant adipokine, plays different roles in tumorigenesis and anti-oncogenic pathways. In present study, we investigated the association of omentin-1 with oxidative stress and clinical significances in healthy controls and BC patients to assess the prognostic and diagnostic value of omentin-1 in this cancer.

Methods: This case-control study included 88 BC patients and 86 healthy controls. The serum levels of omentin-1 were assessed by enzyme-linked immunosorbent assays methods. Also, total antioxidant capacity (TAC), total oxidant status (TOS) and malondialdehyde (MDA) serum levels were measured by spectrophotometer. quantitative real-time polymerase chain reaction (qRT-PCR) was applied to the measurement of gene expression of omentin-1.

Results: the serum levels of omentin-1 were significantly lower in the BC patients compared to the healthy controls (P<0.001). Moreover, gene expression of omentin-1was significantly downregulated in the BC tissues compared to the adjacent normal tissues (P<0.001). Gene expression of omentin-1and its serum levels were significantly higher in grade I compared with grade II and III (P=0.001, P<0.001, respectively). Additionally, the serum levels of omentin-1 in the p53-positive BC patients were significantly higher than the p53-negative BC patients (P=0.001). There was an inverse correlation between the serum levels of MDA and TOS with the serum levels of omentin-1 (r=-0.436, r=-461, respectively).

Conclusion: We conclude that omentin-1 may have a good prognostic and diagnostic roles in the BC patients and decreases oxidative stress in these patients.

Differences in omentin-1 levels in term newborns according to birth weight

BACKGROUND

Adipokines are produced by adipose tissue and are involved in metabolic processes. Omentin-1 is an adipokine that has been shown in vitro to possibly be involved in insulin sensitivity modulation. The prenatal stage is a crucial period for development of metabolic diseases in the long term, therefore, small (SGA) and large (LGA) for gestational age newborns have an increased risk of type 2 diabetes and metabolic syndrome later in life.

AIMS

To evaluate the differences in omentin-1 concentrations in umbilical cord blood from healthy term newborns according to birth weight and explore the association between omentin-1 and anthropometry, glucose, insulin and insulin sensitivity.

STUDY DESIGN

This was a secondary analysis of stored umbilical cord blood of term newborns.

SUBJECTS

Newborns classified according to birth weight as SGA (n = 30), adequate for gestational age (AGA) (n = 12) and LGA (n = 34).

OUTCOME MEASURES

An analysis of omentin-1, glucose and insulin were performed.

RESULTS

Differences were found in serum omentin-1 levels (ng/mL) between SGA 328.17 ± 108.04, AGA 253.05 ± 98.25 and LGA 250.91 ± 100.48 (p = 0.009). In the linear regression analysis, the independent variables HOMA-IR, QUICK-I and FGIR were predictors of serum omentin-1 levels (r = 0.175, p = 0.003).

CONCLUSIONS

Omentin-1 cord blood levels have a differentiated behavior according to weight for gestational age with LGA newborns having lower levels and SGA newborns higher levels. HOMA-IR, QUICK-I and FGIR weakly predicted omentin-1 in cord blood, suggesting that omentin-1 possibly has an implication in insulin sensitivity since birth.

Omentin-1 attenuates lipopolysaccharide (LPS)-induced U937 macrophages activation by inhibiting the TLR4/MyD88/NF-κB signaling

Macrophages play a pivotal role in the defense response against harmful pathogens and stimuli by releasing various pro-inflammatory mediators. However, overproduction of pro-inflammatory mediators will do harm to the organism and cause inflammation-associated diseases. Omentin-1, which is a newly discovered adipokine, is specifically expressed in omental adipose tissue. Recent studies have found correlations between omentin-1 and insulin resistance, diabetes, obesity, inflammation, atherosclerosis, bone metabolism, and tumor cell proliferation. Some studies have shown that the association between omentin-1, insulin resistance, and inflammation might suggest that omentin-1 plays an important role in chronic inflammatory diseases. In this study, we found that omentin-1 inhibited LPS-induced expression of inflammatory mediators and pro-inflammatory cytokines in macrophages. Furthermore, omentin-1 inhibited activation of the NF-κB pathway by suppressing both nuclear p65 accumulation and transfected NFκB promoter activity. Importantly, omentin-1 increased nuclear translocation of Nrf2. Our findings demonstrate that omentin-1 exerts anti-inflammatory effects on LPS-induced macrophages and has potential implication in the treatment of inflammation-associated diseases.

Tanshinone IIA Promotes Macrophage Cholesterol Efflux and Attenuates Atherosclerosis of apoE-/- Mice by Omentin-1/ABCA1 Pathway

BACKGROUND

Tanshinone IIA (Tan IIA) and Omentin-1 have a protective role in the cardiovascular system. However, if and how Tan IIA and Omentin-1 regulate cholesterol metabolism in macrophages has not been fully elucidated.

OBJECTIVE

To investigate the possible mechanisms of Tan IIA and Omentin-1 on preventing macrophage cholesterol accumulation and atherosclerosis development.

METHODS

The effect of Tan IIA on the protein and mRNA levels of Omentin-1 and ATP-binding cassette transporter A1 (ABCA1) in macrophages was examined by Western blot and qRT-PCR assay, respectively. Cholesterol efflux was assessed by liquid scintillation counting (LSC). Cellular lipid droplet was measured by Oil Red O staining, and intracellular lipid content was detected by high performance liquid chromatography (HPLC). In addition, the serum lipid profile of apoE-/- mice was measured by enzymatic method. The size of atherosclerotic lesion areas and content of lipids and collagen in the aortic of apoE-/- mice were examined by Sudan IV, Oil-red O, and Masson staining, respectively.

RESULTS

Tan IIA up-regulated expression of Omentin-1 and ABCA1 in THP-1 macrophages, promoting ABCA1-mediated cholesterol efflux and consequently decreasing cellular lipid content. Consistently, Tan IIA increased reverse cholesterol transport in apoE-/- mice. Plasma levels of high-density lipoprotein cholesterol (HDL-C), ABCA1 expression and atherosclerotic plaque collagen content were increased while plasma levels of low-density lipoprotein cholesterol (LDL-C) and atherosclerotic plaque sizes were reduced in Tan IIA-treated apoE-/- mice. These beneficial effects were, however, essentially blocked by knockdown of Omentin-1.

CONCLUSION

Our results revealed that Tan IIA promotes cholesterol efflux and ameliorates lipid accumulation in macrophages most likely via the Omentin-1/ABCA1 pathway, reducing the development of aortic atherosclerosis.

Association between plasma omentin-1 levels in type 2 diabetic patients and peripheral artery disease

Background

Type-2 diabetes mellitus is one of the major risk factors of atherosclerosis, particularly in peripheral artery disease (PAD). Several studies have documented a correlation between omentin-1 serum levels, atherosclerosis, and cardiovascular diseases. However, a clear link between circulating omentin-1 and PAD in diabetic patients has yet to be established. The aim of this study was to investigate the potential role of omentin-1 in PAD in type-2 diabetic patients.

Methods

In this cross-sectional study, we analyzed omentin-1 serum levels by ELISA in 600 type-2 diabetic patients with (n = 300) and without (n = 300) PAD at Fontaine’s stage II, III, or IV.

Results

We found that omentin-1 serum levels were significantly lower in diabetic patients with PAD than in diabetic controls (29.46 vs 49.24 ng/mL, P < 0.001) and that the levels gradually decreased in proportion to disease severity (P < 0.05). The association between omentin-1 levels and PAD remained significant after adjusting for major risk factors in a multivariate analysis.

Conclusions

Our results suggest that omentin-1 is reduced in type 2 diabetic patients with PAD and that omentin-1 levels are related to disease severity.

The association between Chinese patients' elevated omentin-1 levels, their clinicopathological features, and the risk of colorectal cancer

To investigate the association between plasma omentin-1 levels and the risk of colorectal cancer (CRC) and the pathological changes of CRC, a total of 358 colorectal adenocarcinoma patients were included in the experience group, and 286 people were included in the control group. Their levels of omentin-1, adiponectin, visfatin, leptin, and their anthropometric and metabolic parameters were determined, and we analyzed the tertile distributions in the control group, according to the different levels: low, medium, and high. The results showed that the omentin-1 levels in patients with CRC were higher than the levels in the controls [(67.28 ± 32.25) vs (33.16 ± 19.93) ng/mL, P = 0.005]. The patients with the highest concentration of omentin-1 presented significantly higher odds for CRC, adjusted for potential confounding factors for CRC (odds ratio: 5.76; 95% CI 1.81-8.95; P = 0.001). The plasma omentin-1 level in CRC yielded a receiver operating characteristic curve area of 88.4%. The optimal sensitivity and specificity were 81.2% and 69.8% in discriminating CRC from the normal control. A high omentin-1 level was significantly associated the increasing stage of colorectal adenocarcinomas and the depth of invasion (P = 0.005, 0.026, respectively). The present study suggests an increased level of omentin-1 not only was a strong risk factor for CRC but could also represent a potential biomarker for CRC stage progression and CRC diagnosis in Chinese patients.