Pilot study of frozen platelet extracellular vesicles as a therapeutic agent in hemorrhagic shock in rats.

BACKGROUND: Hemorrhage accounts for the most preventable deaths after trauma. Resuscitation is guided by studies that demonstrate improved outcomes in patients receiving whole blood or balanced administration of blood products. Platelets present a logistical challenge due to short shelf life and need for refrigeration. Platelet-derived extracellular vesicles (PEVs) are a possible platelet alternative. Platelet-derived extracellular vesicles are secreted from platelets, have hemostatic effects and mitigate inflammation and vascular injury, similar to platelets. This pilot study aimed to elucidate the therapeutic effects of PEVs in a rat model of uncontrolled hemorrhage. METHODS: Male rats were anesthetized and femoral vessels cannulated. Vital signs (MAP, HR, and RR) were monitored. Electrolytes, lactate and ABG were obtained at baseline, 1-hour and 3-hours post injury. Laparotomy was performed, 50% of the middle hepatic lobe excised and the abdomen packed with gauze. Rats received 2 mL PEVs or lactated Ringers (LR) over 6 minutes immediately after injury. Peritoneal blood loss was quantified using preweighed gauze at 5 minutes, 15 minutes, 30 minutes, 45 minutes, and 60 minutes. Laparotomy was closed 1-hour postinjury. Animals were monitored for 3 hours postinjury then euthanized. Generalized Linear Mixed Effects models were performed to assess effects of treatment and time on lactate and MAP. RESULTS: Twenty-one rats were included (11 LR, 10 PEV). Overall blood loss was between 6 mL and 10 mL and not significantly different between groups. There was a 36% mortality rate in the LR group and 0% mortality in the PEV group ( p = 0.03). The LR group had significantly higher lactates at 1 hour ( p = 0.025). At 15 minutes, 45 minutes, 60 minutes, and 180 minutes, the MAP of the PEV group was significantly higher than the LR group. CONCLUSION: Early studies are encouraging regarding the potential use of PEVs in uncontrolled hemorrhagic shock based on improved survival and hemodynamics.

Cyclin A2 and Ki-67 proliferation markers could be used to identify tumors with poor prognosis in African American women with breast cancer.

Background: Diagnosed invasive breast carcinomas in African American patients are more aggressive compared with those in Caucasian patients and diagnosed at later stages of the disease with higher grade tumors. Despite advances in breast cancer systemic treatment, new prognostic and predictive biomarkers are still needed. Therefore, potential biomarkers were chosen to correlate with different subtypes, recurrence, and survival of invasive breast cancer in a cohort of African American women. Methods: Eight protein biomarkers (ER, PR, HER2, Cyclin A2, Cytokeratin 5, Vimentin, Bcl2, and Ki-67) were evaluated using tissue microarrays (TMAs) and immunohistochemistry (IHC). The IHC results from TMAs were analyzed by both supervised and unsupervised clustering methods. The predictive clusters for the supervised and unsupervised methods were compared for agreement with the empirical classification. Kappa values were used to determine the overall percent correct clusters and agreement between specific clusters. Chi-square statistics was used to examine the association between hierarchical and multinomial logistic clustering methods. Results: Five subtypes of breast tumors with distinct protein expression patterns were identified among the studied 166 breast tumors. Luminal B tumors have been distinguished from luminal A tumors by staining for cell cycle proteins Cyclin A2 and Ki-67, which promote cell proliferation. Forty-nine percent were stained positive for Cyclin A2, 39.2% positive for Ki-67, and 37% positive for both Cyclin A2 and Ki-67. The age of patients did not show any significant effect whether five (p-value= 0.576) or eight (p-value= 0.605) biomarkers were used, which indicating that age did not have any influence on the classification of the subtypes. Ninety percent of the thirty triple negative tumors were positive for Cyclin A2 or Ki-67 or both. Six-year overall survival was better for luminal A tumors (76%) than luminal B tumors (71%). Likewise, six-year relapse-free survival was better for luminal A tumors (76%) than luminal B tumors (29%). Conclusion: Discovery of molecular markers such as Cyclin A2 and Ki-67, and subtypes that are most prevalent in African Americans could lead to a better understanding of the factors contributing to higher morbidity and mortality in this group and to aid in decision-making to offer earlier treatment.