Ines G. Alamo

Characterization of erythropoietin and hepcidin in the regulation of persistent injury-associated anemia.

BACKGROUND The cause of persistent injury-associated anemia is multifactorial and includes acute blood loss, an altered erythropoietin (EPO) response, dysregulation of iron homeostasis, and impaired erythropoiesis in the setting of chronic inflammation/stress. Hepcidin plays a key role in iron homeostasis and is regulated by anemia and inflammation. Erythropoietin is a main regulator of erythropoiesis induced by hypoxia. A unique rodent model of combined lung injury (LC)/hemorrhagic shock (HS) (LCHS)/chronic restraint stress (CS) was used to produce persistent injury-associated anemia to further investigate the roles of EPO, hepcidin, iron, ferritin, and the expression of EPO receptors (EPOr). METHODS Male Sprague-Dawley rats were randomly assigned into one of the four groups of rodent models: naive, CS alone, combined LCHS, or LCHS/CS. Plasma was used to evaluate levels of EPO, hepcidin, iron, and ferritin. RNA was isolated from bone marrow and lung tissue to evaluate expression of EPOr. Comparisons between models were performed by t tests followed by one-way analysis of variance. RESULTS After 7 days, only LCHS/CS was associated with persistent anemia despite significant elevation of plasma EPO. Combined LCHS and LCHS/CS led to a persistent decrease in EPOr expression in bone marrow on Day 7. The LCHS/CS significantly decreased plasma hepcidin levels by 75% on Day 1 and 84% on Day 7 compared to LCHS alone. Hepcidin plasma levels are inversely proportional to EPO plasma levels (Pearson R = −0.362, p < 0.05). CONCLUSION Tissue injury, hemorrhagic shock, and stress stimulate and maintain high levels of plasma EPO while hepcidin levels are decreased. In addition, bone marrow EPOr and plasma iron availability are significantly reduced following LCHS/CS. The combined deficit of reduced iron availability and reduced bone marrow EPOr expression may play a key role in the ineffective EPO response associated with persistent injury-associated anemia.

Daily propranolol administration reduces persistent injury-associated anemia following severe trauma and chronic stress.

BACKGROUND After severe trauma, patients develop a norepinephrine-mediated persistent, injury-associated anemia. This anemia is associated with suppression of bone marrow (BM) erythroid colony growth, along with decreased iron levels, and elevated erythropoietin (EPO) levels, which are insufficient to promote effective erythropoiesis. The impact of norepinephrine on iron regulators, such as ferroportin, transferrin, and transferrin receptor-1 (TFR-1), is unknown. Using a clinically relevant rodent model of lung contusion (LC), hemorrhagic shock (HS), and chronic stress (CS), we hypothesize that daily propranolol (BB), a nonselective &bgr; blocker, restores BM function and improves iron homeostasis. METHODS Male Sprague-Dawley rats were subjected to LCHS ± BB and LCHS/CS ± BB. BB was achieved with propranolol (10 mg/kg) daily until the day of sacrifice. Hemoglobin, plasma EPO, plasma hepcidin, BM cellularity and BM erythroid colony growth were assessed. RNA was isolated to measure transferrin, TFR-1 and ferroportin expression. Data are presented as mean ± SD; *p < 0.05 versus untreated counterpart by t test. RESULTS The addition of CS to LCHS leads to persistent anemia on posttrauma day 7, while the addition of BB improved hemoglobin levels (LCHS/CS: 10.6 ± 0.8 vs. LCHS/CS + BB: 13.9 ± 0.4* g/dL). Daily BB use after LCHS/CS improved BM cellularity, colony-forming units granulocyte, erythrocyte, monocyte megakaryocyte, burst-forming unit erythroid and colony-forming unit erythroid cell colony growth. LCHS/CS + BB significantly reduced plasma EPO levels and increased plasma hepcidin levels on day 7. The addition of CS to LCHS resulted in decreased liver ferroportin expression as well as decreased BM transferrin and TFR-1 expression, thus, blocking iron supply to erythroid cells. However, daily BB after LCHS/CS improved expression of all iron regulators. CONCLUSION Daily propranolol administration after LCHS/CS restored BM function and improved anemia after severe trauma. In addition, iron regulators are significantly reduced after LCHS/CS, which may contribute to iron restriction after injury. However, daily propranolol administration after LCHS/CS improved iron homeostasis.

Clonidine reduces norepinephrine and improves bone marrow function in a rodent model of lung contusion, hemorrhagic shock, and chronic stress.

Background. Propranolol has been shown previously to restore bone marrow function and improve anemia after lung contusion/hemorrhagic shock. We hypothesized that daily clonidine administration would inhibit central sympathetic outflow and restore bone marrow function in our rodent model of lung contusion/hemorrhagic shock with chronic stress. Methods. Male Sprague‐Dawley rats underwent 6 days of restraint stress after lung contusion/hemorrhagic shock during which the animals received clonidine (75 &mgr;g/kg) after the restraint stress. On postinjury day 7, we assessed urine norepinephrine, blood hemoglobin, plasma granulocyte colony stimulating factor, and peripheral blood mobilization of hematopoietic progenitor cells, as well as bone marrow cellularity and erythroid progenitor cell growth. Results. The addition of clonidine to lung contusion/hemorrhagic shock with chronic restraint stress significantly decreased urine norepinephrine levels, improved bone marrow cellularity, restored erythroid progenitor colony growth, and improved hemoglobin (14.1 ± 0.6 vs 10.8 ± 0.6 g/dL). The addition of clonidine to lung contusion/hemorrhagic shock with chronic restraint stress significantly decreased hematopoietic progenitor cells mobilization and restored granulocyte colony stimulating factor levels. Conclusion. After lung contusion/hemorrhagic shock with chronic restraint stress, daily administration of clonidine restored bone marrow function and improved anemia. Alleviating chronic stress and decreasing norepinephrine is a key therapeutic target to improve bone marrow function after severe injury.

Abstract A94: Treatment disparities in pancreatic cancer: “Does our survival depend on where we go for care?”

Introduction: Pancreatic cancer is the 4th leading cancer in the US with dismal survival rates with an overall five-year survival rate of 4%. Surgery remains the only potentially curative treatment of localized/early pancreatic cancer (PC). Additionally, treatment at tertiary care centers provides a significant survival advantage for patients resected with pancreatic cancer. In the State of Florida, blacks (African-Americans) have a greater incidence of PC rates than whites (Caucasians). Observations demonstrate that blacks are much less likely to undergo appropriate medical care in a tertiary care center such as University of Florida Health Cancer Center (UFHCC). Therefore, we evaluated treatment disparities among black patients afflicted with PC in Northern Florida. Methods: In northern and central Florida, UFHCC is the major tertiary cancer center. Data was collected from the Florida Cancer Database System and University of Florida Health medical records. With IRB approval, data was collected and reviewed from 2000 to 2011 from all patients diagnosed or treated with PC. Results: Between 2000-2011, 995 patients underwent consultation at UFHCC for PC (89% white vs 9% black). More blacks than whites (65% vs. 56%) presented with advanced stage III or IV disease but only 5% presented with resectable disease (Stage I or II) compared to 20% whites. Additionally, 603 blacks were diagnosed with PC in northern Florida but only 93 of these patients (15%) sought care at UFHCC for management of their disease. Of these patients, 58 % were females, 42 % were males. Large majority of blacks did not ever receive consultation at our tertiary care center. Interestingly, for blacks that were transferred from a center not specializing in PC to UFHCC with persistent disease (71% vs. 47%) had a significant survival advantage. Discussion/Conclusion: In Florida, compared to whites, blacks have a higher incidence of PC but presented fewer times to UFHCC and with more advanced disease. Blacks were more likely to receive their care in very low volume hospitals and have limited access to specialists. In northern Florida, there is a clear discontinuity of care for blacks between diagnosis and access to treatment in a tertiary care center. Treatment disparities such as a lack of access to tertiary care centers, a lower likelihood to be offered surgery at a resectable stage, and patient refusal of surgical intervention have shown to play a role in adequate continuity of care among blacks. Whether treatment disparities have a statistically significant affect on survival rate of pancreatic cancer among blacks has yet to be formally evaluated. We encourage the call for further investigations in minority populations in other regions of the United States. There is strong need for research to whether these factors play a role in clinical outcomes where the disparity is becoming more evident. Citation Format: Ines G. Alamo, Marcia A. Hodges, Kevin E. Behrns, Steve J. Hughes, Thomas J. George, Jr., Jose G. Trevino. Treatment disparities in pancreatic cancer: “Does our survival depend on where we go for care?” [abstract]. In: Proceedings of the Seventh AACR Conference on The Science of Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; Nov 9-12, 2014; San Antonio, TX. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2015;24(10 Suppl):Abstract nr A94.