Erythropoiesis in multiply injured patients

Propranolol treatment during repetitive mild traumatic brain injuries induces transcriptomic changes in the bone marrow of mice

Introduction

There are 1.5 million new mild traumatic brain injuries (mTBI) annually in the US, with many of the injured experiencing long-term consequences lasting months after the injury. Although the post injury mechanisms are not well understood, current knowledge indicates peripheral immune system activation as a causal link between mTBI and long-term side effects. Through a variety of mechanisms, peripheral innate immune cells are recruited to the CNS after TBI to repair and heal the injured tissue; however, the recruitment and activation of these cells leads to further inflammation. Emerging evidence suggests sympathetic nervous system (SNS) activity plays a substantial role in the recruitment of immune cells post injury.

Methods

We sought to identify the peripheral innate immune response after repeated TBIs in addition to repurposing the nonselective beta blocker propranolol as a novel mTBI therapy to limit SNS activity and mTBI pathophysiology in the mouse. Mice underwent repetitive mTBI or sham injury followed by i.p. saline or propranolol. Isolated mRNA derived from femur bone marrow of mice was assayed for changes in gene expression at one day, one week, and four weeks using Nanostring nCounter® stem cell characterization panel.

Results

Differential gene expression analysis for bone marrow uncovered significant changes in many genes following drug alone, mTBI alone and drug combined with mTBI.

Discussion

Our data displays changes in mRNA at various timepoints, most pronounced in the mTBI propranolol group, suggesting a single dose propranolol injection as a viable future mTBI therapy in the acute setting.

Adrenergic Modulation of Erythropoiesis After Trauma

Severe traumatic injury results in a cascade of systemic changes which negatively affect normal erythropoiesis. Immediately after injury, acute blood loss leads to anemia, however, patients can remain anemic for as long as 6 months after injury. Research on the underlying mechanisms of such alterations of erythropoiesis after trauma has focused on the prolonged hypercatecholaminemia seen after trauma. Supraphysiologic elevation of catecholamines leads to an inhibitive effect on erythropoiesis. There is evidence to show that alleviation of the neuroendocrine stress response following trauma reduces these inhibitory effects. Both beta blockade and alpha-2 adrenergic receptor stimulation have demonstrated increased growth of hematopoietic progenitor cells as well as increased pro-erythropoietic cytokines after trauma. This review will describe prior research on the neuroendocrine stress response after trauma and its consequences on erythropoiesis, which offer insight into underlying mechanisms of prolonged anemia postinjury. We will then discuss the beneficial effects of adrenergic modulation to improve erythropoiesis following injury and propose future directions for the field.

Mild hypobaric hypoxia influences splenic proliferation during the later phase of stress erythropoiesis

Tissue trauma and hemorrhagic shock are common battlefield injuries that can induce hypoxia, inflammation, and/or anemia. Inflammation and hypoxia can initiate adaptive mechanisms, such as stress erythropoiesis in the spleen, to produce red blood cells and restore the oxygen supply. In a military context, mild hypobaric hypoxia-part of the environmental milieu during aeromedical evacuation or en route care-may influence adaptive mechanisms, such as stress erythropoiesis, and host defense. In the present study, healthy (control), muscle trauma, and polytrauma (muscle trauma and hemorrhagic shock) mice were exposed to normobaric normoxia or hypobaric hypoxia for ∼17.5 h to test the hypothesis that hypobaric hypoxia exposure influences splenic erythropoiesis and splenic inflammation after polytrauma. This hypothesis was partially supported. The polytrauma + hypobaric hypoxia group exhibited more splenic neutrophils, fewer total spleen cells, and fewer splenic proliferating cells than the polytrauma+normobaric normoxia group; however, no splenic erythroid cell differences were detected between the two polytrauma groups. We also compared splenic erythropoiesis and myeloid cell numbers among control, muscle trauma, and polytrauma groups. More reticulocytes at 1.7 days (40 h) post-trauma (dpt) and neutrophils at 4 dpt were produced in the muscle trauma mice than corresponding control mice. In contrast to muscle trauma, polytrauma led to a reduced red blood cell count and elevated serum erythropoietin levels at 1.7 dpt. There were more erythroid subsets and apoptotic reticulocytes in the polytrauma mice than muscle trauma mice at 4 and 8 dpt. At 14 dpt, the red blood cell count of the polytrauma + normobaric normoxia mice was 12% lower than that of the control + normobaric normoxia mice; however, no difference was observed between polytrauma + hypobaric hypoxia and control + hypobaric hypoxia mice. Our findings suggest muscle trauma alone induces stress erythropoiesis; in a polytrauma model, hypobaric hypoxia exposure may result in the dysregulation of splenic cells, requiring a treatment plan to ensure adequate immune functioning.

Potential Efficacy of Erythropoietin on Reducing the Risk of Mortality in Patients with Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Objective

The objective of this study is to assess the effectiveness of erythropoietin (EPO) on mortality, neurological outcomes, and adverse event in the treatment of traumatic brain injury (TBI).

Methods

We searched databases including PubMed, OVID, and the Cochrane Library from inception until October 18, 2019 for randomized controlled trials (RCTs) to compare EPO treatment group and placebo in patients with TBI. Two authors independently processed the data and evaluated the quality of inclusion studies. Statistical analysis was performed with heterogeneity test with I ² and chi-square tests. We summarized the mortality, prognosis of neurological function, and deep vein thrombosis (DVT) outcomes and presented as risk ratio (RR) or risk difference (RD) with a 95% CI.

Results

Seven RCTs accounting for 1180 patients were included after meeting the inclusion criteria. Compared with placebo, the overall mortality of EPO-treated patients was significantly reduced (RR 0.68 [95% CI 0.50-0.93]; p = 0.02). EPO therapy did not improve neurological prognosis (RR 1.21 [95% CI 0.93-1.15]; p = 0.16) or increase the occurrence of DVT (RR 0.83 [95% CI 0.61-1.13]; p = 0.242), which showed no significant difference.

Conclusions

The results showed that the administration of EPO may reduce the risk of mortality without enhancing the occurrence of DVT in TBI patients. However, the effect of EPO on neurological outcome remains indistinct. Through subgroup analysis, we demonstrated that the dose of EPO may be a potential factor affecting the heterogeneity in neurological function and that the follow-up duration may influence the stability of the result.

NAD+ homeostasis in health and disease

The conceptual evolution of nicotinamide adenine dinucleotide (NAD⁺) from being seen as a simple metabolic cofactor to a pivotal cosubstrate for proteins regulating metabolism and longevity, including the sirtuin family of protein deacylases, has led to a new wave of scientific interest in NAD⁺. NAD⁺ levels decline during ageing, and alterations in NAD⁺ homeostasis can be found in virtually all age-related diseases, including neurodegeneration, diabetes and cancer. In preclinical settings, various strategies to increase NAD⁺ levels have shown beneficial effects, thus starting a competitive race to discover marketable NAD⁺ boosters to improve healthspan and lifespan. Here, we review the basics of NAD⁺ biochemistry and metabolism, and its roles in health and disease, and we discuss current challenges and the future translational potential of NAD⁺ research.

The Postinjury Inflammatory State and the Bone Marrow Response to Anemia

RATIONALE

The pathophysiology of persistent injury-associated anemia is incompletely understood, and human data are sparse.

OBJECTIVES

To characterize persistent injury-associated anemia among critically ill trauma patients with the hypothesis that severe trauma would be associated with neuroendocrine activation, erythropoietin dysfunction, iron dysregulation, and decreased erythropoiesis.

METHODS

A translational prospective observational cohort study comparing severely injured, blunt trauma patients who had operative fixation of a hip or femur fracture (n = 17) with elective hip repair patients (n = 22). Bone marrow and plasma obtained at the index operation were assessed for circulating catecholamines, systemic inflammation, erythropoietin, iron trafficking pathways, and erythroid progenitor growth. Bone marrow was also obtained from healthy donors from a commercial source (n = 8).

MEASUREMENTS AND MAIN RESULTS

During admission, trauma patients had a median of 625 ml operative blood loss and 5 units of red blood cell transfusions, and Hb decreased from 10.5 to 9.3 g/dl. Compared with hip repair, trauma patients had higher median plasma norepinephrine (21.9 vs. 8.9 ng/ml) and hepcidin (56.3 vs. 12.2 ng/ml) concentrations (both P < 0.05). Bone marrow erythropoietin and erythropoietin receptor expression were significantly increased among patients undergoing hip repair (23% and 14% increases, respectively; both P < 0.05), but not in trauma patients (3% and 5% increases, respectively), compared with healthy control subjects. Trauma patients had lower bone marrow transferrin receptor expression than did hip repair patients (57% decrease; P < 0.05). Erythroid progenitor growth was decreased in trauma patients (39.0 colonies per plate; P < 0.05) compared with those with hip repair (57.0 colonies per plate; P < 0.05 compared with healthy control subjects) and healthy control subjects (66.5 colonies per plate).

CONCLUSIONS

Severe blunt trauma was associated with neuroendocrine activation, erythropoietin dysfunction, iron dysregulation, erythroid progenitor growth suppression, and persistent injury-associated anemia. Clinical trial registered with www.clinicaltrials.gov (NCT 02577731).

Anemia and blood transfusion in elderly trauma patients

BACKGROUND

The natural history of postinjury among elderly trauma patients has not been well described. We hypothesized that elderly trauma patients would have lower admission hemoglobin (Hb) levels, higher transfusion rates, and worse outcomes than young trauma patients.

METHODS

We performed a propensity-matched retrospective cohort analysis comparing elderly (age ≥65 y) to young (age 18-64) trauma patients matched by sex, mechanism of injury, Injury Severity Score, base deficit, comorbidities, operative blood loss, and phlebotomy blood loss (n = 41/group). Outcomes included Hb trends, packed red blood cell (PRBC) transfusion, length of stay, and mortality.

RESULTS

Elderly patients had lower admission Hb (11.3 versus 10.2 g/dL, P = 0.012), received more PRBC transfusions within 24 h (3.6 versus 1.8 units, P = 0.046), and during admission (6.9 versus 4.3 units, P = 0.008). Despite receiving more PRBC transfusions and having similar operative and phlebotomy blood loss, elderly subjects had lower discharge Hb (9.0 versus 9.7 g/dL, P = 0.013). Elderly subjects had fewer ICU-free days (2.0 versus 6.0 d, P < 0.001) and higher in-hospital mortality (15% versus 0%, P = 0.026).

CONCLUSIONS

Elderly trauma patients had lower admission Hb, received more transfusions, and had persistently lower Hb on discharge when controlling for injury severity, comorbid conditions, and blood loss. Aging may have a negative impact on postinjury anemia.

The effects of propranolol and clonidine on bone marrow expression of hematopoietic cytokines following trauma and chronic stress

BACKGROUND

Attenuating post-injury neuroendocrine stress abrogates persistent injury-associated anemia. Our objective was to examine the mechanisms by which propranolol and clonidine modulate this process. We hypothesized that propranolol and clonidine would decrease bone marrow expression of high-mobility group box-1 (HMGB1) and increase expression of stem cell factor (SCF) and B-cell lymphoma-extra large (Bcl-xL).

METHODS

Male Sprague-Dawley rats were allocated to naïve control, lung contusion followed by hemorrhagic shock (LCHS), or LCHS plus daily chronic restraint stress (LCHS/CS) ±propranolol, ±clonidine. Day seven bone marrow expression of HMGB1, SCF, and Bcl-xL was assessed by polymerase chain reaction.

RESULTS

Following LCHS, HMGB1 was decreased by propranolol (49% decrease, p = 0.012) and clonidine (54% decrease, p < 0.010). SCF was decreased following LCHS/CS, and was increased by propranolol (629% increase, p < 0.001) and clonidine (468% increase, p < 0.001). Bcl-xL was decreased following LCHS/CS, and was increased by propranolol (59% increase, p = 0.006) and clonidine (77% increase, p < 0.001).

CONCLUSIONS

Following severe trauma, propranolol and clonidine abrogate persistent injury-associated anemia by modulating bone marrow cytokines, favoring effective erythropoiesis.

Hypoalbuminemia: Pathogenesis and Clinical Significance

Hypoalbuminemia is associated with inflammation. Despite being addressed repeatedly in the literature, there is still confusion regarding its pathogenesis and clinical significance. Inflammation increases capillary permeability and escape of serum albumin, leading to expansion of interstitial space and increasing the distribution volume of albumin. The half‐life of albumin has been shown to shorten, decreasing total albumin mass. These 2 factors lead to hypoalbuminemia despite increased fractional synthesis rates in plasma. Hypoalbuminemia, therefore, results from and reflects the inflammatory state, which interferes with adequate responses to events like surgery or chemotherapy, and is associated with poor quality of life and reduced longevity. Increasing or decreasing serum albumin levels are adequate indicators, respectively, of improvement or deterioration of the clinical state. In the interstitium, albumin acts as the main extracellular scavenger, antioxidative agent, and as supplier of amino acids for cell and matrix synthesis. Albumin infusion has not been shown to diminish fluid requirements, infection rates, and mortality in the intensive care unit, which may imply that there is no body deficit or that the quality of albumin “from the shelf” is unsuitable to play scavenging and antioxidative roles. Management of hypoalbuminaemia should be based on correcting the causes of ongoing inflammation rather than infusion of albumin. After the age of 30 years, muscle mass and function slowly decrease, but this loss is accelerated by comorbidity and associated with decreasing serum albumin levels. Nutrition support cannot fully prevent, but slows down, this chain of events, especially when combined with physical exercise.

The effects of beta blockade and clonidine on persistent injury-associated anemia

BACKGROUND

Nonselective beta blockade (BB) and clonidine may abrogate catecholamine-mediated persistent injury-associated anemia. We hypothesized that critically ill trauma patients who received BB or clonidine would have favorable hemoglobin (Hb) trends when adjusting for operative blood loss (OBL), phlebotomy blood loss (PBL), and red blood cell (RBC) transfusion volumes, and that the effect would be greatest among the elderly, who have higher catecholamine levels.

METHODS

We performed a 4-y retrospective cohort analysis of 280 consecutive trauma patients with ICU stay ≥48 h and moderate/severe anemia. Patients who received BB or clonidine for ≥25% of their hospital stay were grouped as the BB/clonidine cohort (n = 84); all other patients served as controls (n = 196). Admission and discharge Hb were used to calculate ΔHb. OBL, PBL, and RBC volume were used to calculate adjusted ΔHb assuming 300 mL RBC = 1 g/dL Hb.

RESULTS

BB/clonidine and control patients had similar age, injury severity, comorbid illness, and admission Hb. BB/clonidine patients received fewer RBCs despite greater OBL, though neither association was statistically significant. BB/clonidine patients had higher discharge Hb (9.9 versus 9.5, P = 0.029) and adjusted ΔHb (+1.0 versus -0.8, P = 0.003). Hb curves separated after hospital day 10. The difference in adjusted ΔHb between groups increased with advanced age (all patients: 1.7, ≥50 y: 1.8, ≥60 y: 2.4, ≥70 y: 3.7).

CONCLUSIONS

Critically ill trauma patients receiving BB or clonidine had favorable Hb trends when accounting for OBL, PBL, and RBC transfusions. These findings support the hypothesis that BB and clonidine alleviate persistent injury-associated anemia, with strongest effects among the elderly.

Persistent injury-associated anemia and aging: Novel insights

BACKGROUND

Hypercatecholaminemia and bone marrow dysfunction have been implicated in the pathophysiology of persistent injury-associated anemia. The elderly may be more vulnerable to bone marrow dysfunction due to high basal and peak catecholamine levels and impaired hematopoietic progenitor growth. We hypothesized that aging would adversely affect persistent injury-associated anemia.

METHODS

Male Sprague-Dawley rats aged 8 to 9 weeks and F344-BN rats aged 25 months were randomized to naive controls, lung contusion plus hemorrhagic shock (LCHS), and LCHS plus daily chronic restraint stress (LCHS/CS). Urine norepinephrine was measured on Days 1 and 7. Mobilization of hematopoietic progenitor cells (HPCs), bone marrow colony-forming units-erythroid growth, and peripheral blood hemoglobin, mean corpuscular volume (MCV), and red cell distribution width (RDW) were assessed on Day 7 (*p < 0.05 young vs. aged counterpart by one-way analysis of variance).

RESULTS

Aged rats had higher norepinephrine levels at naive baseline (97* vs. 27 ng/mL) and 7 days following LCHS/CS when compared with young (359* vs. 127 ng/mL). Following LCHS/CS, HPC mobilization was greater among young rats when compared with aged (5.4 vs. 2.5%). Colony-forming units-erythroid growth was lower among aged animals for each group (naive: 47* vs. 65; LCHS: 40* vs. 50; LCHS/CS: 38* vs. 44 cells/plate). Aged naive rats had higher initial hemoglobin (15.2* vs. 14.3 g/dL) but lower MCV (48* vs. 59 fL/cell) and larger RDW at baseline and greater differences 7 days after LCHS/CS (MCV: 46* vs. 60 fL/cell; RDW: 17.4* vs. 16.3%).

CONCLUSIONS

Compared with young rats, aged rats had less HPC mobilization despite elevated basal and peak norepinephrine. Aged rats were disproportionately affected by impaired hematopoietic progenitor growth and an iron-restricted red blood cell phenotype at baseline, which persisted 7 days after injury. Further research is needed to assess how the clinical approach to persistent injury-associated anemia should differ for elderly trauma patients.

Persistent injury-associated anemia in aged rats

BACKGROUND

Hypercatecholaminemia and bone marrow dysfunction have been implicated in the pathophysiology of persistent-injury associated anemia. The elderly may be vulnerable to this phenomenon due to high basal and peak catecholamine levels, impaired erythroid progenitor growth, and baseline anemia. We hypothesized that aged F344-BN rats subjected to severe trauma and chronic stress would have persistent injury-associated anemia.

METHODS

Male F344-BN rats age 25months were randomly allocated to: naïve (n=8), lung contusion (LC, n=9), LC followed by daily chronic restraint stress (LC/CS, n=9), LC followed immediately by hemorrhagic shock (LCHS, n=8), and LCHS followed by daily CS (LCHS/CS, n=8). Urine norepinephrine was measured on days one and seven. Locomotor testing was performed on day five. Bone marrow cellularity, hematopoietic progenitor growth, and peripheral blood hemoglobin levels were assessed at sacrifice on day seven. Data are presented as mean±standard deviation, *p<0.05 vs. naïve.

RESULTS

Norepinephrine levels (ng/mL) were significantly elevated one day after LCHS (420±239* vs. naïve: 97±71) and LCHS/CS (375±185*), and remained significantly elevated on day seven for LCHS/CS (359±99*), but not LCHS (212±130). On locomotor testing, groups subjected to CS traveled shorter distances at lower velocities and spent less time in the center of the cage. Colony forming units-erythroid (colonies/plate), representing late erythroid progenitors, were significantly decreased after LC/CS (40±1* vs. naïve: 47±4), LCHS (40±1*), and LCHS/CS (38±3*). LCHS/CS animals had significantly lower hemoglobin (g/dL) than naïve animals (13.3±1.3* vs. naïve: 15.2±0.9).

CONCLUSIONS

Persistent injury-associated anemia occurs in aged rats. Further research is needed to determine whether the pathophysiology of this phenomenon differs from that of younger rats, and to translate these findings to elderly trauma patients.

Evaluation of circulating haematopoietic progenitor cells in patients with Trauma Haemorrhagic shock and its correlation with outcomes

Background:

Haemorrhagic shock accounts up to 50% of early trauma deaths. Hematopoietic failure has been observed in experimental animals and human following shock and injury. One of the facets of bone marrow failure is multiple organ dysfunction syndrome and is commonly seen in patients recovering from severe trauma and hemorrhagic shock. Bone Marrow (BM) dysfunction is associated with mobilization of hematopoietic progenitor cells (HPCs) into peripheral blood. Present study explored the association of peripheral blood hematopoietic progenitor cells (HPCs) with mortality in trauma haemorrhagic shock patients (T/HS).

Materials and Methods:

Prospective cohort studies of patients presenting within 8 hrs of injury with T/HS to the Department of Emergency Medicine, Jai Prakash Narayan Apex Trauma Center, All India Institute of Medical Sciences were recruited. Peripheral blood samples were collected in each patient for measurement of peripheral blood HPCs. Peripheral blood progenitor cell (PBPC) quantification was performed by measuring HPCs counts using the haematology analyzer (Sysmex XE-2100). Clinical and laboratory data were prospectively collected after consent. Ethical approval was taken and data was analysed by Stata 11.2.

Results:

39 patients with trauma hemorrhagic shock and 30 normal healthy controls were recruited. HPCs were significantly higher (P < 0.001) in the T/HS as compared to control. Among study group, 14 patients died within 24 h. at the hospital admission, and found HPCs concentrations were highly significant (<0.001) in non-survivors (n = 14) when compared with survivors (n = 25) among T/HS patients.

Conclusions:

Our studies suggest the peripheral blood HPCs may be early prognostic marker for mortality among patients who presented with trauma hemorrhagic shock on admission. But the exact molecular mechanism and signalling pathway involved in the change of the behaviour of bone marrow microenvironment is still unclear.

Impaired hematopoietic progenitor cells in trauma hemorrhagic shock

Hemorrhagic shock (HS) is the major cause of death during trauma. Mortality due to HS is about 50%. Dysfunction of hematopoietic progenitor cells (HPCs) has been observed during severe trauma and HS. HS induces the elevation of cytokines, granulocyte-colony stimulating factor (G-CSF), peripheral blood HPCs, and circulating catecholamines, and decreases the expression of erythropoietin receptor connected with suppression of HPCs. Impaired HPCs may lead to persistent anemia and risk of susceptibility to infection, sepsis, and MOF. There is a need to reactivate impaired HPCs during trauma hemorrhagic shock.

Bone marrow hematopoietic stem cells behavior with or without growth factors in trauma hemorrhagic shock

Background:

Hemorrhagic shock (HS) is the major leading cause of death after trauma. Up to 50% of early deaths are due to massive hemorrhage. Excessive release of pro-inflammatory cytokine and hypercatecholamine induces hematopoietic progenitor cells (HPCs) apoptosis, leading to multiorgan failure and death. However, still, result remains elusive for hematopoietic stem cells (HSCs) behavior in trauma HS (T/HS).

Objectives:

Therefore, our aim was to evaluate the in vitro HSCs behavior with or without recombinant human erythropoietin (rhEPO), recombinant human granulocyte macrophage-colony-stimulating factor (rhGM-CSF), recombinant human interleukin-3 (rhIL-3) alone, and combination with rhEPO + rhGM-CSF + rhIL-3 (EG3) in T/HS patients.

Methodology:

Bone marrow (BM) aspirates (n = 14) were collected from T/HS patients, those survived on day 3. BM cells were cultured for HPCs: Colony-forming unit-erythroid (CFU-E), burst-forming unit-erythroid (BFU-E), and colony-forming unit-granulocyte, monocyte/macrophage colonies growth. HPCs were counted with or without rhEPO, rhGM-CSF, rhIL-3 alone, and combination with EG3 in T/HS patients.

Results:

BM HSCs growth significantly suppressed in T/HS when compared with control group (P < 0.05). In addition, CFU-E and BFU-E colony growth were increased with additional growth factor (AGF) (rhEPO, rhGM-CSF, and rhIL-3) as compared to baseline (without AGF) (P < 0.05).

Conclusion:

Suppressed HPCs may be reactivated by addition of erythropoietin, GM-CSF, IL-3 alone and with combination in T/HS.

Protocols for massive blood transfusion: when and why, and potential complications

PURPOSE

An update paper on massive bleeding after major trauma. A review of protocols to address massive bleeding, and its possible complications, including coagulation abnormalities, complications related to blood storage, immunosuppression and infection, lung injury associated with transfusion, and hypothermia is carried out.

METHODS

Literature review and discussion with authors' experience.

RESULTS

Massive bleeding is an acute life-threatening complication of major trauma, and consequently its prompt diagnosis and treatment is of overwhelming importance. Treatment requires rapid surgical management together with the massive infusion of colloid and blood.

CONCLUSIONS

Since massive transfusion provokes further problems in patients who are already severely traumatized and anaemic, once this course of action has been decided upon, a profound knowledge of its potential complications, careful monitoring and proper follow-up are all essential. To diagnose this bleeding, most authors favour, as the main first choice tool, a full-body CT scan (head to pelvis), in non-critical severe trauma cases. In addition, focused abdominal sonography for trauma (FAST, an acronym that highlights the necessity of rapid performance) is a very important diagnostic test for abdominal and thoracic bleeding. Furthermore, urgent surgical intervention should be undertaken for patients with significant free intraabdominal fluid and haemodynamic instability. Although the clinical situation and the blood haemoglobin concentration are the key factors considered in this rapid decision-making context, laboratory markers should not be based on a single haematocrit value, as its sensitivity to significant bleeding may be very low. Serum lactate and base deficit are very sensitive markers for detecting and monitoring the extent of bleeding and shock, in conjunction with repeated combined measurements of prothrombin time, activated partial thromboplastin time, fibrinogen and platelets.

Transfusion begets anemia: the effect of aged blood on hematopoiesis

BACKGROUND

Following trauma, transfusion of aged stored blood is often necessary yet associated with increased morbidity and mortality. Despite blood replacement, many patients have a prolonged anemia requiring further transfusions. The effects of aged blood on bone marrow (BM) hematopoiesis have not been studied, and we hypothesized that stored blood suppresses BM function.

METHODS

Blood from Sprague-Dawley rats was stored for 1, 14, or 28 days with the industry preservative citrate-phosphate-dextrose-adenine-1 (CPDA-1). For in vitro studies, 5% supernatant was incubated with normal rat BM and cultured for erythroid (CFU-E) and granulocyte-macrophage (CFU-GM) colony-forming units. Data were compared with cultures of BM alone, 5% control plasma (negative control), and 12% CPDA-1. For in vivo studies, rats were transfused with stored supernatants (5% estimated blood volume (EBV) over 30 minutes). BM from each recipient was cultured for CFU-E and CFU-GM at 3 hours after transfusion. Data were compared with cultures of BM alone. Difference between groups determined by analysis of variance and Tukey's multiple comparison test.

RESULTS

In vitro exposure to CPDA-1, control plasma, or 1-day supernatant (D1) had no effect on BM growth compared with BM alone. In vitro exposure to 14-day (D14) and 28-day (D28) supernatant significantly suppressed CFU-E by 60% and CFU-GM growth by 71% (both p < 0.05) compared with D1 or medial alone. There were no differences between D14 and D28. In vivo exposure to D14 reduced BM CFU-E and CFU-GM growth by 55% (both p < 0.05) compared with D1 supernatant.

CONCLUSION

Plasma from aged blood adversely affects CFU-E and CFU-GM growth in rats. The effect is not mediated by CPDA-1. Transfusion of aged stored blood may contribute to BM dysfunction in critically ill patients, resulting in persistent anemia and the need for further transfusion. This BM dysfunction may also partly explain the observed increased susceptibility to infection.

Impact of erythropoietin on intensive care unit patients

Anemia is common in intensive care unit (ICU) patients. Red blood cell (RBC) transfusions are mainstays of their treatment and can be life-saving. Allogeneic blood components inherently bear risks of infection and immune reactions. Although these risks are rare in developed countries, recombinant human erythropoietin (rhEpo) and other erythropoiesis-stimulating agents (ESAs) have been considered alternative anti-anemia treatment options. As summarized herein, however, most of the clinical studies suggest that ESAs are not usually advisable in ICU patients unless approved indications exist (e.g., renal disease). First, ESAs act in a delayed way, inducing an increase in reticulocytes only after a lag of 3-4 days. Second, many critically ill patients present with ESA resistance as inflammatory mediators impair erythropoietic cell proliferation and iron availability. Third, the ESA doses used for treatment of ICU patients are very high. Fourth, ESAs are not legally approved for general use in ICU patients. Solely in distinct cases, such as Jehovah's Witnesses who refuse allogeneic blood transfusions due to religious beliefs, ESAs may be considered an exceptional therapy.

Erythropoietin in the intensive care unit: beyond treatment of anemia

Erythropoietin (EPO) is the major hormone stimulating the production and differentiation of red blood cells. EPO is used widely for treating anemia of critical illness or anemia induced by chemotherapy. EPO at pharmacological doses is used in this setting to raise hemoglobin levels (by preventing the apoptosis of erythroid progenitor cells) and is designed to reduce patient exposure to allogenic blood through transfusions. Stroke, heart failure, and acute kidney injury are a frequently encountered clinical problem. Unfortunately, in the intensive care unit advances in supportive interventions have done little to reduce the high mortality associated with these conditions. Tissue protection with EPO at high, nonpharmacological doses after injury has been found in the brain, heart, and kidney of several animal models. It is now well known that EPO has anti-apoptotic effects in cells other than erythroid progenitor cells, which is considered to be independent of EPOs erythropoietic activities. This review article summarizes what is known in preclinical models of critical illness and discusses why this does not correlate with randomized, controlled clinical trials.

Complications of massive transfusion

Massive transfusion (MT) is a lifesaving treatment of hemorrhagic shock, but can be associated with significant complications. The lethal triad of acidosis, hypothermia, and coagulopathy associated with MT is associated with a high mortality rate. Other complications include hypothermia, acid/base derangements, electrolyte abnormalities (hypocalcemia, hypomagnesemia, hypokalemia, hyperkalemia), citrate toxicity, and transfusion-associated acute lung injury. Blood transfusion in trauma, surgery, and critical care has been identified as an independent predictor of multiple organ failure, systemic inflammatory response syndrome, increased infection, and increased mortality in multiple studies. Once definitive control of hemorrhage has been established, a restrictive approach to blood transfusion should be implemented to minimize further complications.

Removal of erythropoietin from anaemia trauma practice guideline does not increase red blood cell transfusions and decreases hospital utilization costs

INTRODUCTION

We previously demonstrated that utilization of erythropoietin (r-EPO) did not significantly reduce blood utilization in trauma patients. We undertook this study to analyze blood utilization 1 year after r-EPO removal from our trauma service anaemia practice management guideline.

METHODS

Electronic records of patients admitted to the trauma service were retrospectively reviewed for units of packed red blood cells (pRBCs) transfused and for units of r-EPO administered 12 months before the initiation of an anaemia practice guideline (PRE), 12 months during the use of an anaemia guideline (GUIDE), and 12 months following removal of r-EPO from the guideline (POST). Hospital acquisition cost was also reviewed for the respective time periods. Nominal data were analyzed using chi-squared or Fisher's exact tests, and interval data were compared using ANOVA followed by Tukey's test where appropriate. Results were considered significant for P<0.05.

RESULTS

Over the 3-year study period, 4881 patients were admitted to the trauma service and included in this study. The hospital length of stay, intensive care unit length of stay, and units of pRBC transfused were similar among all three groups. Group I (PRE) received a total of 228 doses of r-EPO at a cost of $102,600. Group II (GUIDE) received a total of 410 doses at a cost of $184,500. Group III (POST) received 28 doses of r-EPO at a cost of $12,600.

CONCLUSION

Removal of erythropoietin from our trauma service anaemia practice management guideline did not result in increased blood utilization. However, it yielded a hospital acquisition cost savings of $171,900.

Infection with Anaplasma phagocytophilum induces multilineage alterations in hematopoietic progenitor cells and peripheral blood cells

Infection with Anaplasma phagocytophilum, a gram-negative, lipopolysaccharide (LPS)-negative, obligate intracellular bacterium, results in multiple peripheral blood cytopenias. We hypothesized that infection with this organism would result in decreased bone marrow (BM) function and shifts in hematopoietic progenitor cells (HPCs) and lineage-committed cells in a well-established murine model of infection. HPCs and lineage-committed progenitors were enumerated in the BM and spleen during acute infection. BM cytokine production and BM CXCL12 expression were determined. Infection resulted in peripheral blood bicytopenia, marked decreases in the number of lineage-committed HPCs in the BM along with concurrent increases in the number of lineage-committed HPCs in the spleen, and a mixed, predominantly myelosuppressive BM cytokine environment. There was significant downregulation of CXCL12 in BM cells that may have been partially responsible for changes in HPC trafficking observed. Changes occurred in the absence of direct pathogen infection of BM cells. Hematopoietic lineage assessment demonstrated that there was loss of erythrocytes and B lymphocytes from the BM along with increased granulopoiesis. These changes were accompanied by splenomegaly due to lymphoid hyperplasia and increased hematopoiesis, most notably erythropoiesis. These changes largely mimic well-described inflammation and endotoxin-mediated effects on the BM and spleen; however, the numbers of peripheral blood neutrophils appear to be independently modulated as granulocytic hyperplasia does not result in neutrophilia. Our findings highlight a well-conserved series of events that we demonstrate can be instigated by an LPS-negative pathogen in the absence of an endotoxin-mediated acute proinflammatory response.

Dangers, and benefits of the cytokine mediated response to injury and infection

The inflammatory response is essential for survival in an environment where continuous exposure to noxious events threaten the integrity of the organism. However, the beneficial effects of the response are influenced by factors, which disadvantage individuals within a population. These factors include malnutrition, infection, genotype, gender, pre-existing inflammation, and chronic intoxication. Although the inflammatory response is generally successful in dealing with noxious events, life-long exposure to these events takes its toll on the integrity of the body and becomes apparent as chronic disease, atherosclerosis, organ failure, and frailty. Progress in ameliorating the consequences of lifetime exposure to inflammatory events can only occur if a fuller understanding can be obtained of the factors, which influence the persistence and outcome of the inflammatory response at an individual level. A multitude of studies has shown that specific nutrients, diets, and dietary restriction are able to modulate the inflammatory response in the population as a whole. To advance in this area, precise knowledge is needed of how the disadvantageous factors, mentioned above, affect the individual's response to anti-inflammatory nutrients.

Diminished hematopoietic activity associated with alterations in innate and adaptive immunity in a mouse model of human monocytic ehrlichiosis

Human monocytic ehrlichiosis (HME) is a tick-borne disease caused by Ehrlichia chaffeensis. Patients exhibit diagnostically important hematological changes, including anemia and thrombocytopenia, although the basis of the abnormalities is unknown. To begin to understand these changes, we used a mouse model of ehrlichiosis to determine whether the observed hematological changes induced by infection are associated with altered hematopoietic activity. Infection with Ehrlichia muris, a pathogen closely related to E. chaffeensis, resulted in anemia, thrombocytopenia, and a marked reduction in bone marrow cellularity. CFU assays, conducted on days 10 and 15 postinfection, revealed a striking decrease in multipotential myeloid and erythroid progenitors. These changes were accompanied by an increase in the frequency of immature granulocytes in the bone marrow and a decrease in the frequency of B lymphocytes. Equally striking changes were observed in spleen cellularity and architecture, and infected mice exhibited extensive extramedullary hematopoiesis. Splenomegaly, a characteristic feature of E. muris infection, was associated with an expanded and disorganized marginal zone and a nearly 66-fold increase in the level of Ter119(+) erythroid cells, indicative of splenic erythropoiesis. We hypothesize that inflammation associated with ehrlichia infection suppresses bone marrow function, induces the emigration of B cells, and establishes hematopoietic activity in the spleen. We propose that these changes, which may be essential for providing the innate and acquired immune cells to fight infection, are also responsible in part for blood cytopenias and other clinical features of HME.

Mechanism of the salutary effects of estrogen on kupffer cell phagocytic capacity following trauma-hemorrhage: pivotal role of Akt activation

Kupffer cells are macrophages in the liver whose major role is to clear circulating pathogens. Decreased phagocytic capacity of Kupffer cells may result in severe systemic infection. We tested the hypothesis that the depressed Kupffer cell phagocytic capacity following trauma-hemorrhage is enhanced by estrogen administration and this occurs due to maintenance of Fc receptor expression and cellular ATP content via the activation of Akt. Male C3H/HeN mice were subjected to sham operation or trauma-hemorrhage and sacrificed 2 h thereafter. Estrogen, with or without an estrogen receptor antagonist (ICI 182,780), a PI3K inhibitor (Wortmannin), or vehicle, was injected during resuscitation. Kupffer cell phagocytic capacity was tested in vivo. The expression of Fc receptors, of Akt phosphorylation, of p38 MAPK phosphorylation, of DNA binding activity of NF-kappaB and ATP content of Kupffer cells were also determined. Trauma-hemorrhage suppressed Kupffer cell phagocytosis by decreasing Fc receptor expression and Akt activation; however, it induced p38 MAPK activation and increased NF-kappaB activity. Cellular ATP levels were also decreased following trauma-hemorrhage. Administration of estrogen following trauma-hemorrhage increased phospho-Akt levels and normalized all the parameters described as well as plasma levels of TNF-alpha, IL-6, and IL-10. Coadministration of ICI 182,780 or Wortmannin abolished the beneficial effects of estrogen in improving the phagocytic capacity of Kupffer cells following trauma-hemorrhage. Thus, activation of Akt plays a crucial role in mediating the salutary effect of estrogen in restoring trauma-hemorrhage-induced suppression of Kupffer cell phagocytosis.

The role of erythropoietin in the acute phase of trauma management: evidence today

Trauma patients often present in a state of haemorrhagic shock. Blood products remain the gold standard of resuscitation, but allogeneic blood transfusions (ABTs) are associated with several risks. The stimulating effect of recombinant-erythropoietin (EPO-A) on erythropoiesis has raised interest in its administration as an alternative. The existing evidence on the early use of EPO-A in the acute phase of trauma patients management consists of only 14 publications. The level of evidence of these studies and the number of treated patients was not found to be adequate to support its generalised use, despite their favourable results. Its safety profile, the preliminary proofs of its efficacy, and the additional cyto-protective properties of EPO-A strongly encourage further controlled studies assessing its use in the acute setting of initial trauma management.

Phlebotomies or erythropoietin injections allow mobilization of iron stores in a mouse model mimicking intensive care anemia

OBJECTIVE

Anemia in critically ill patients is frequent and consists of chronic disease associated with blood losses. These two mechanisms have opposite effects on iron homeostasis, especially on the expression of the iron regulatory hormone hepcidin. We developed a mouse model mimicking the intensive care anemia to explore iron homeostasis.

DESIGN

Experimental study.

SETTING

University-based research laboratory.

SUBJECTS

C57BL/6 mice.

INTERVENTIONS

Mice received either a single intraperitoneal injection of lipopolysaccharide followed 1 week later by zymosan, or were subjected to repeated phlebotomies by retro-orbital punctures, or both. Several subsets of mice were analyzed over a 14-day period to describe the mouse model of intensive care anemia. Additional mice received erythropoietin injections with or without the zymosan treatment and were killed at day 5, to perform a more detailed analysis.

MEASUREMENTS AND MAIN RESULTS

We observed anemia as soon as 5 days after zymosan injection, together with increased messenger RNA (mRNA) levels for interleukin-6 and hepcidin. Phlebotomies alone fully suppressed hepcidin mRNA expression. Interestingly, in mice treated with zymosan and phlebotomies, hepcidin expression was suppressed, despite the persistent increase in interleukin-6. Stimulation of erythropoiesis by erythropoietin injections also led to a decrease in hepcidin mRNA in zymosan-treated mice. In these situations combining inflammation and erythropoiesis stimulation, there was no change in ferroportin, the membrane iron exporter, at the mRNA level, whereas ferroportin protein increased. Macrophage iron stores (assessed by histology using diaminobenzidine staining, or by quantification of nonheme iron and ferritin concentrations) were depleted in the spleen.

CONCLUSIONS

These results suggest that the erythroid factor dominates over inflammation for hepcidin regulation, and that iron could be mobilized in these situations combining inflammation and erythropoiesis stimulation.

Erythropoietin measurements in severely traumatized patients

BACKGROUND

Despite numerous studies in critically ill patients, physiological adaptation to acute anaemia and the pattern of erythropoietin (EPO) secretion has not been well described in severely injured patients. The aim of this study was to describe EPO secretion and its relationship with haemoglobin (Hb) levels in severely injured patients.

METHODS

We performed an observational, prospective clinical study in our intensive care unit (ICU). For all patients with severe trauma (Injury Severity Score>15), EPO measurement was obtained on admission, during the first 3 days and then when Hb level was measured. Maximal EPO level (EPOmax) and minimal Hb level (Hbmin) during the ICU stay was determined for all patients.

RESULTS

One hundred and seventy-one consecutives patients were included (440 EPO measurements). Seventy-nine patients (46.2%) showed an increased value (> or =25 UI/l) EPOmax value. Most EPOmax values were observed early after the trauma [within 4 days for 63 patients (82.8%)]. Plotting EPOmax to Hbmin values show that a threshold Hbmin value of 105 g/l best discriminated patients with and without an elevated EPO secretion. Less than 10% of the patients with Hbmin<105 g/l did not increase their EPO secretion.

CONCLUSION

In severely traumatized patients a marked response to acute anaemia is observed in most patients. In our study, Hb threshold for a significant EPO secretion following post-traumatic acute anaemia was 105 g/l. The peak level was achieved early in the course of the anaemia.

Impaired erythropoiesis after haemorrhagic shock in mice is associated with erythroid progenitor apoptosis in vivo

OBJECTIVE

Multiply traumatised patients often suffer from blood loss and from subsequent therapy-resistant anaemia, possibly mediated by apoptosis, necrosis, or humoral factors. Therefore, the underlying mechanisms were investigated in bone marrow (BM) and peripheral blood in a murine resuscitated haemorrhagic shock (HS) model.

METHODS

In healthy male mice, pressure-controlled HS was induced for 60 min. The BM was analysed for Annexin-V, 7-amino-actinomycin D, apoptotic enzymes (caspases-3/7, -8, and -9), expression of death receptors (CD120a, CD95), mitochondrial proteins (Bax, Bcl-2, Bcl-x), as well as erythropoietin (EPO) receptor (EPO-R). Blood cell count, peripheral EPO, and tumour necrosis factor-alpha response were additionally monitored.

RESULTS

Twenty-four and 72 h after HS, EPO and EPO-R were strongly up-regulated in peripheral blood and BM, respectively. Decreasing numbers of erythroid progenitors in BM after HS correlated with significant apoptotic changes confirmed by increased caspases-3/7, -8, -9 activity in total BM, death receptor CD95 and CD120a expression on erythroid progenitors, and down-regulated mitochondrial Bcl-2 expression in total BM. Erythroid progenitors in peripheral blood were found to be increased after 72 h.

CONCLUSION

Despite the massive EPO response and up-regulation of EPO-R, BM erythroblasts (EBs) decreased. This could be due to deficient maturation of erythroid progenitors. Furthermore, the increased intrinsic and extrinsic apoptosis activation suggests programmed death of erythroid progenitors. We propose that both apoptosis and negatively regulated erythropoiesis contribute to BM dysfunction, while erythroid progenitor egress plays an additional role.

Neurobiology confirms psychopathology. On the antagonism of psychosis and obsessive-compulsive syndromes

BACKGROUND

Psychopathological concepts of the 19th and early 20th century postulated an antagonism between psychotic and obsessive-compulsive disorders, assuming obsessions and compulsions to have protective effects on psychotic disintegration. Although both disorders have been subject to intense multimodal research, their pathogeneses are yet to be fully understood.

METHODS

Here, we discuss recent neurobiological findings pointing towards opposite directions which are strongly reminiscent of the historical psychopathological antagonism.

RESULTS

Obsessive-compulsive syndromes (OCS) are efficiently treated with serotonergic substances, while on the other hand modern antipsychotic drugs exert antiserotonergic effects. Especially these atypical antipsychotic substances, however, were found to involve the risk of inducing second-onset OCS. Dopamine antagonists are potent antipsychotic substances, whereas the partial dopamine agonist aripiprazole has been associated with an antiobsessive potency. Within the glutamatergic system, reduced NMDA-dependent glutamatergic neurotransmission is discussed to be one major pathomechanism of psychotic disorders, whilst NMDA antagonists have proven to be effective in improving treatment-resistant OCS. While neurogenetic findings seem to separate the populations in heterogeneous samples, detailed neuroimaging studies suggest that both disorders affect similar neurocircuits in different manners.

CONCLUSIONS

With regard to these findings, future research on schizo-obsessive syndromes will have to be multimodal, integrating psychopathology, neuropsychology, functional imaging, neurogenetics and psychopharmacology. Prospective trials involving these methods might be able to elucidate the dysbalances of neurotransmission and to locate the neuroanatomical and neuropsychological correlates. In particular, this might contribute to defining schizophrenic patients at risk for developing second-onset OCS and to evaluating new treatment strategies in patients suffering from both psychosis and OCS.