C1q/TNF‐related protein 9: A novel therapeutic target in ischemic stroke?

Serum CTRP9 and high-molecular weight adiponectin are associated with ischemic stroke

Background

C1q/TNF-related protein 9 (CTRP9) and adiponectin (APN) have beneficial metabolic regulatory and vasoprotective effects. This study explored alteration of CTRP9 and APN multimers during onset of ischemic stroke and development, to provide novel clinical and experimental basis for recognition and prevention of ischemic stroke.

Methods

There were 269 patients with ischemic stroke and 182 control subjects included in this study. Serum levels of CTRP9 and APN multimers in different disease stages were measured.

Results

Serum CTRP9, total APN (tAPN), and high-molecular weight (HMW) APN decreased gradually in stage I (acute stage, within 72 h of onset) of ischemic stroke and increased during stage III (11th day to one month) and stage IV (1 month after), compared to control. In the non-hyperlipidemia group, serum CTRP9, tAPN, and HMW were decreased in ischemic stroke patients compared to control (P < 0.05). Serum CTRP9 is closely related to serum tAPN and HMW (r = 0.992, 0.991). Serum CTRP9 are protective against ischemic stroke (OR = 0.400, 95% CI 0.197–0.810, P < 0.05).

Conclusions

Lower serum CTRP9, tAPN, LMW, and HMW are significantly associated with increased ischemic stroke risk in non-hyperlipidemia subjects. CTRP9, tAPN, and HMW isoforms may be valuable clinical indicators for patients with ischemic stroke.

Crocins for Ischemic Stroke: A Review of Current Evidence

Crocins (CRs) and the related active constituents derived from Crocus sativus L. (Saffron) have demonstrated protective effects against cerebral ischemia and ischemic stroke, with various bioactivities including neuroprotection, anti-neuroinflammation, antioxidant, and cardiovascular protection. Among CRs, crocin (CR) has been shown to act on multiple mechanisms and signaling pathways involved in ischemic stroke, including mitochondrial apoptosis, nuclear factor kappa light chain enhancer of B cells pathway, S100 calcium-binding protein B, interleukin-6 and vascular endothelial growth factor-A. CR is generally safe and well-tolerated. Pharmacokinetic studies indicate that CR has poor bioavailability and needs to convert to crocetin (CC) in order to cross the blood-brain barrier. Clinical studies have shown the efficacy of saffron and CR in treating various conditions, including metabolic syndrome, depression, Alzheimer’s disease, and coronary artery disease. There is evidence supporting CR as a treatment for ischemic stroke, although further studies are needed to confirm their efficacy and safety in clinical settings.

Salivary Xanthine Oxidase as a Potential Biomarker in Stroke Diagnostics

Stroke is one of the most common cerebrovascular diseases. Despite significant progress in understanding stroke pathogenesis, cases are still increasing. Thus, laboratory biomarkers of stroke are sought to allow rapid and non-invasive diagnostics. Ischemia-reperfusion injury is an inflammatory process with characteristic cellular changes leading to microvascular disruption. Several studies have shown that hyperactivation of xanthine oxidase (XO) is a major pathogenic factor contributing to brain dysfunction. Given the critical role of XO in stroke complications, this study aimed to evaluate the activity of the enzyme and its metabolic products in the saliva of stroke subjects. Thirty patients in the subacute phase of stroke were included in the study: 15 with hemorrhagic stroke and 15 with ischemic stroke. The control group consisted of 30 healthy subjects similar to the cerebral stroke patients regarding age, gender, and status of the periodontium, dentition, and oral hygiene. The number of individuals was determined a priori based on our previous experiment (power of the test = 0.8; α = 0.05). The study material was mixed non‐stimulated whole saliva (NWS) and stimulated saliva (SWS). We showed that activity, specific activity, and XO output were significantly higher in NWS of ischemic stroke patients than in hemorrhagic stroke and healthy controls. Hydrogen peroxide and uric acid levels were also considerably higher in NWS of ischemic stroke patients. Using receiver operating curve (ROC) analysis, we demonstrated that XO-specific activity in NWS distinguishes ischemic stroke from hemorrhagic stroke (AUC: 0.764) and controls (AUC: 0.973) with very high sensitivity and specificity. Saliva collection is stress-free, requires no specialized medical personnel, and allows continuous monitoring of the patient’s condition through non-invasive sampling multiple times per day. Salivary XO also differentiates with high accuracy (100%) and specificity (93.75%) between stroke patients with mild to moderate cognitive decline (AUC = 0.988). Thus, salivary XO assessment may be a potential screening tool for a comprehensive neuropsychological evaluation. To summarize, our study demonstrates the potential utility of salivary XO in the differential diagnosis of stroke.

C1q/Tumor Necrosis Factor-Related Protein 9: Basics and Therapeutic Potentials

C1q/tumor necrosis factor-related protein 9 (CTRP9) is a newly discovered adipokine that is the closest paralog of adiponectin. Proteolytic cleavage of CTRP9 leads to the release of the globular domain (gCTRP9), which serves as the major circulating subtype. After binding with adiponectin receptor 1 (AdipoR1) and N-cadherin, CTRP9 activates various signaling pathways to regulate glucose and lipid metabolism, vasodilation and cell differentiation. Throughout human development and adult life, CTRP9 controls many biological phenomena. simultaneously, abnormal gene or protein expression of CTRP9 is accompanied by a wide range of human pathological phenomena. In this review, we briefly introduce CTRP9 and its associated signaling pathways and physiological functions, which may be helpful in the understanding of the occurrence of diseases. Moreover, we summarize the broader research prospects of CTRP9 and advances in therapeutic intervention. In recent years, CTRP9 has attracted extensive attention due to its role in the pathogenesis of various diseases, providing further avenues for its exploitation as a potential biomarker or therapeutic target.

Association Between Serum C1q Tumor Necrosis Factor-Related Protein 9 and the Clinical Characteristics and Prognosis of Ischemic Stroke

Introduction

C1q tumor necrosis factor (TNF)-related protein 9 (CTRP9) is a novel member of the C1q/TNF superfamily. According to our previous review, CTRP9 plays a vital role in the process of cardiovascular diseases, including regulating energy metabolism, modulating vasomotion, protecting endothelial cells, inhibiting platelet activation, inhibiting pathological vascular remodeling, stabilizing atherosclerotic plaques, and protecting the heart. We proposed that CTRP9 could play multiple positive and beneficial roles in vascular lesions in ischemic stroke (IS). Here, we aimed to study the relationship between serum CTRP9 and the etiology, severity, and prognosis of IS patients.

Methods

A total of 302 patients with IS and 173 non-stroke controls were selected from the same hospital, and all patients with IS were followed up 12 months after stroke onset. Stroke etiology was classified according to the Trial of ORG 10172 in Acute Stroke Treatment classification. Symptomatic severity was determined using the National Institutes of Health Stroke Scale score. The lesion volume of acute cerebral ischemia was measured using magnetic resonance imaging (MRI). The unfavorable functional outcome was a combination of death or major disability 12 months after stroke onset. Receiver operating characteristic (ROC) curves and integrated discrimination improvement (IDI) and net reclassification improvement (NRI) statistics were applied in the statistical analysis.

Results

We found that serum CTRP9 levels and the ratios of CTRP9/total cholesterol (TC), CTRP9/triglyceride (TG), CTRP9/low-density lipoprotein cholesterol (LDL-C), and CTRP9/high-density lipoprotein cholesterol (HDL-C) were associated with the presence of IS. Moreover, the serum CTRP9 concentration was positively associated with the severity of IS. Incorporation of CTRP9/LDL-C levels into a fully adjusted model for IS-cardioembolic (CE) improved discrimination and calibration, and significantly improved reclassification. In addition, CTRP9 was a predictor of unfavorable functional outcomes.

Conclusions

All the findings indicated that serum CTRP9 could be a promising blood-derived biomarker for the early evaluation and prognosis assessment of IS.

Trial Registration

Chinese Clinical Trial Registry, ChiCTR1800020330.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-021-00296-7.

Salivary cytokine profile in patients with ischemic stroke

Inflammation plays a crucial role in stroke pathogenesis. Thus, it is not surprising that cytokines, chemokines, and growth factors have been advocated in stroke diagnostics. Our study is the first to evaluate the salivary cytokine profile in patients with ischemic stroke. Twenty-five patients with subacute ischemic stroke and an age-, sex-, and oral hygiene status-matched control group were enrolled in the study. The number of patients was set a priori based on our previous experiment (α = 0.05, test power = 0.9). Salivary concentrations of tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and interleukin 10 (IL-10) were assessed using an ELISA method. We showed that salivary TNF-α and IL-6 were significantly higher, whereas IL-10 content was statistically lower in both non-stimulated (NWS) and stimulated (SWS) whole saliva of ischemic stroke patients. However, evaluation of cytokines in NWS rather than in SWS may be of greater diagnostic value. Of particular note is salivary TNF-α, which may indicate cognitive/physical impairment in post-stroke individuals. This parameter distinguishes stroke patients from healthy controls and correlates with cognitive decline and severity of functional impairment. It also differentiates (with high sensitivity and specificity) stroke patients with normal cognition from mild to moderate cognitive impairment. Saliva may be an alternative to blood for assessing cytokines in stroke patients, although further studies on a larger patient population are needed.

CTRP9: An emerging potential anti-aging molecule in brain

C1q/tumor necrosis factor (TNF)-related proteins (CTRPs) particularly CTRP9, have been established to be as adiponectin (APN) highly conserved paralogs which assemble several APN regulatory functions. Recently, growing body of evidences drawn significant attention to evaluate metabolic and cardiovascular effect of CTRP9. However, the potential role of CTRP9 in brain tissue has not yet fully illustrated. Here, we aimed to uncover latest advances regarding the CTRP9 related signaling pathways and during brain aging process.

C1q/TNF-related protein-9 alleviates airway inflammation in asthma

BACKGROUNDS

Asthma is characterized as inflammatory disorder in the respiratory system with increasing tendency. Most of the asthma patients suffered from the disease since childhood. Thus, developing novel therapeutic targets of childhood asthma is necessary. Here, we conducted the present study to investigate the effects of CTRP9 (C1q tumor necrosis factor-related protein 9), a newly identified anti-inflammatory factor, on asthma.

METHODS

Sixty asthmatic children (30 moderate and 30 mild) were recruited. The mRNA level of CTRP9 in peripheral blood mononuclear cells (PBMCs) and protein level of CTRP9 in serum and induced sputum (IS) samples from asthma patients and healthy controls (HCs) were measured by qPCR and ELISA, respectively. The anti-inflammatory effects of CTRP9 was determined in vitro and potential therapeutic effect on asthma was evaluated in mouse model.

RESULTS

The mRNA and protein levels of CTRP9 was significantly down-regulated in asthmatics than HCs. Furthermore, the expression level of CTRP9 was negatively correlated with the expression of TNF-α, IL-1β, and IL-6 in PBMCs. The CTRP9 significantly suppressed the expression of pro-inflammatory factors in PBMCs and sputum cells from asthma patients in vitro. And delivering CTRP9 into mouse model of asthma showed disease alleviation.

CONCLUSION

Our data here indicated that CTRP9 may alleviate airway inflammation and remodeling in asthma.

C1q/TNF-related protein-9 attenuates atherosclerosis through AMPK-NLRP3 inflammasome singling pathway

BACKGROUNDS

C1q tumor necrosis factor-related protein 9 (CTRP9) has been suggested to exert an atheroprotective effect by modulating the inflammation, foam cell formation, endothelia and smooth muscle cell function via Adenosine Monophosphate Activated Protein Kinase (AMPK) pathway. On the other hand, the NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome plays an critical role in the atherosclerosis development, which is regulated by the AMPK. However, whether the CTRP9 affects the activity of NLRP3 inflammasome during the atherosclerosis development remains unclear, which would be elucidated in the current study.

METHODS

The macrophage cells were stimulated with the oxidized low-density lipoprotein (ox-LDL) and also treated with the recombinant CTRP9 in the meantime. The activation of NLRP3 inflammasome was determined by measuring the releasing of IL-1β and caspase-1 p10 via ELISA and western blot, respectively. Then the AMPK was inhibited in macrophages by Dorsomorphin. Finally, the CTRP9-AMPK-NLRP3 inflammasome pathway was validated in the mouse model of atherosclerosis.

RESULTS

The CTRP9 could down-regulate the expression of NLRP3 protein and also the activity of NLRP3 inflammasome in the ox-LDL activated macrophages. Inhibiting the AMPK significantly restored the activities of NLRP3 inflammasome. In the apolipoprotein E-deficient mice, lentiviral expression of CTRP9 could suppress the atherosclerosis development, which could be abolished by AMPK inhibition.

CONCLUSION

Our data here indicated that the CTRP9 showed atheroprotective function via CTRP9-AMPK- NLRP3 inflammasome pathway.