CD200 is overexpressed in the pancreatic tumor microenvironment and predictive of overall survival

Pancreatic cancer is an aggressive disease with a 5 year survival rate of 13%. This poor survival is attributed, in part, to limited and ineffective treatments for patients with metastatic disease, highlighting a need to identify molecular drivers of pancreatic cancer to target for more effective treatment. CD200 is a glycoprotein that interacts with the receptor CD200R and elicits an immunosuppressive response. Overexpression of CD200 has been associated with differential outcomes, depending on the tumor type. In the context of pancreatic cancer, we have previously reported that CD200 is expressed in the pancreatic tumor microenvironment (TME), and that targeting CD200 in murine tumor models reduces tumor burden. We hypothesized that CD200 is overexpressed on tumor and stromal populations in the pancreatic TME and that circulating levels of soluble CD200 (sCD200) have prognostic value for overall survival. We discovered that CD200 was overexpressed on immune, stromal, and tumor populations in the pancreatic TME. Particularly, single-cell RNA-sequencing indicated that CD200 was upregulated on inflammatory cancer-associated fibroblasts. Cytometry by time of flight analysis of PBMCs indicated that CD200 was overexpressed on innate immune populations, including monocytes, dendritic cells, and monocytic myeloid-derived suppressor cells. High sCD200 levels in plasma correlated with significantly worse overall and progression-free survival. Additionally, sCD200 correlated with the ratio of circulating matrix metalloproteinase (MMP) 3: tissue inhibitor of metalloproteinase (TIMP) 3 and MMP11/TIMP3. This study highlights the importance of CD200 expression in pancreatic cancer and provides the rationale for designing novel therapeutic strategies that target this protein.

Laryngeal mask airway vs endotracheal tube to facilitate bedside percutaneous tracheostomy in critically ill patients: a prospective comparative study

BACKGROUND

Inadvertent puncture of endotracheal tube (ETT) cuff and accidental tracheal extubation are the potential life threatening complications during percutaneous dilatational tracheostomy (PDT). As an alternative to ETT, the laryngeal mask airway (LMA) has been used sporadically but no large study is available on its use.

AIMS

To study the use of LMA during PDT on controlled ventilation in critically sick patients and compare its advantages and disadvantages in relation to ETT.

SETTINGS AND DESIGN

This prospective, randomised, comparative study was conducted in intensive care unit of a super-speciality, tertiary care hospital.

METHODS AND MATERIAL

The bedside PDT was performed in 60 critically ill patients using Ciaglia's kit. The patients received controlled ventilation of lungs either through ETT or LMA. The feasibility of the procedure and complications were compared in two groups.

RESULTS

In LMA group, 33% of patients suffered with potentially catastrophic complications, e.g., loss of airway, inadequate ventilation of lungs leading to significant hypoxia, gastric distension and regurgitation. In ETT group there were 6.6% incidence of ETT impalement, 6.6% cuff puncture and 3.3% accidental tracheal extubation. Despite the technical difficulties (cuff puncture, etc.) the ETT technique was basically safe, whereas despite of the theoretical advantages the LMA technique rendered some patients at considerable risks of hypoxia and gastric regurgitation-aspiration.

CONCLUSION

The LMA does not provide safe patent airway to facilitate bedside PDT in critically sick population on controlled ventilation. The ETT is safer for controlled ventilation and should be continued to secure the airway for this purpose until a better alternative is available.