High-Dose Vitamin C Alleviates Pancreatic Necrosis by Inhibiting Platelet Activation Through the CXCL12/CXCR4 Pathway in Severe Acute Pancreatitis

Abstract

Background

Platelet activation in the early stage of pancreatitis is the key step developing into pancreatic necrosis. Studies suggested that vitamin C (Vit C) can inhibit platelet activity by targeting CXCL12/CXCR4 pathway. High-dose Vit C were showed to reduce pancreatic necrosis in severe acute pancreatitis (SAP) but the mechanism remains unclear. Here we speculate high-dose Vit C reduce pancreatic necrosis by inhibiting platelet activation through downregulating CXCL12/CXCR4 pathway.

Methods

The pancreatic microcirculation of rats was observed by intravital microscopy. The platelet activity of SAP rats treated with or without high-dose Vit C was analyzed by platelet function test. Besides, the activity of platelets preincubated with high-dose Vit C or vehicle from SAP patients was also evaluated. Then, the TFA (CXCR4 agonist) and rCXCL12 were used to neutralize the effect of high-dose Vit C in SAP rats treated with high-dose Vit C. Meanwhile, the levels of enzymes and inflammatory cytokines in rat plasma, and rats’ pancreatic histopathology and mortality were assessed.

Results

Platelets from animals and patients with SAP are more sensitive to agonists and are more easily activated. Administration of high-dose Vit C significantly ameliorated excessive activation of platelets in SAP rats, ultimately increasing the microvessel density and inducing microthrombus and blood stasis; these results were consistent with clinical sample analysis. Moreover, high-dose Vit C significantly inhibited the release of amylase, lipase, TNF-α, and IL-6 in SAP rat plasma, reducing pancreatic damage and the mortality of SAP rats. However, using TFA and rCXCL12 significantly reversed the effect of high-dose Vit C on excessive activation of platelets, aggravating microcirculation impairment and pancreatic damage.

Conclusion

The present study suggests that high-dose Vit C can ameliorate pancreatic necrosis by improving microcirculation disorders of SAP. For the first time, the underlying mechanism is related with inhibiting platelet activation through the CXCL12/CXCR4 pathway.

Keywords:

• severe acute pancreatitis
• microcirculation impairment
• platelets activity
• vitamin C
• CXCL12/CXCR4 pathway

Abbreviations

ANP, Acute necrotizing pancreatitis; AP, Acute pancreatitis; SAP, Severe acute pancreatitis; Vit C, Vitamin C; MOF, Multiple organ failure; IPN, Infected pancreatic necrosis; TFA, ATI-2341 TFA; rCXCL12, recombination CXCL12; SDF-1, Stromal-derived factor 1; CXCR4, CXC chemokine receptor 4; PGE1, Prostaglandin E1; TRITC, Tetraethyl rhodamine isothiocyanate; HRP, horseradish peroxidase; FITC, Fluorescein isothiocyanate; PRP, Platelet-rich plasma; GEO, Gene Expression Omnibus; OMIM, Online Mendelian Inheritance; DEGs, Differentially expressed genes; RT-qPCR, Real-time Quantitative Polymerase Chain Reaction; NF-κB, nuclear factor kappa-B.

Data Sharing Statement

The data sets used and analyzed in our study are available from the corresponding author upon reasonable request.

Animal Ethical Approval Statement

All animal studies (including the rats euthanasia procedure) were done in compliance with the regulations and guidelines of Shanghai Jiaotong University institutional animal care and conducted according to the AAALAC and the IACUC guidelines. All animal experiments were approved by the Ethics Committee of Ruijin Hospital of Shanghai Jiao Tong University School of Medicine.

Ethics Approval and Informed Consent

The study followed guidelines enshrined in the Declaration of Helsinki and was duly granted ethical clearance by Ethics Committee of Ruijin Hospital of Shanghai Jiao Tong University School of Medicine vide their approval number (2018) 临伦审第 (145) 号, dated 29th August 2018. All participants read and understood the information leaflet and signed the consent form prior to recruitment.

Acknowledgments

We thank all contributors of the Core Facility of Basic Medical Sciences, Shanghai Jiao Tong University School of Medicine.

Author Contributions

Menglu Gui, Jun Huang, and Huiqiu Sheng share first authorship. All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors declare that they have no competing interests.

Additional information

Funding

This research was supported by Clinical Research Project of Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine (2018CR004), and shanghai natural science fund (21ZR1440400).