Automated analyzer evaluation of reticulocytes in bone marrow and peripheral blood of hematologic disorders

The effect of pre-operative autologous blood donation on bone marrow hematopoietic functions in rabbits after hepatectomy

BACKGROUND

Pre-operative autologous blood donation (PABD) is one of the most widely distributed autologous blood donation means, which has positive effect on erythropoiesis. However, whether PABD can stimulate the bone marrow hematopoiesis after hepatectomy have not been reported.

METHODS

Totally 80 New Zealand rabbits were randomly divided into 4 groups that included control group, surgery group, hemodilutional autotransfusion (HA) group and PABD group. Automatic reticulocyte examination was performed to detect the content of reticulocyte and immature reticulocyte fractions (IRF). Flow cytometric analysis was employed to monitor the level of CD34+ cells and the cell cycle status. Southern blotting was conducted to determine the telomere length of CD34+ cells.

RESULTS

The content of high fluorescence reticulocytes (HFR) and IRF was decreased at 6 h and 24 h after autotransfusion. However, the level of CD34+ cells was upregulated after PABD. Cell cycle status analysis revealed that majority of the CD34+ cells in HA and PABD group were maintained in G0/G1 phase. The telomere length in HA and PABD group was shorten than that of control group and surgery group.

CONCLUSION

PABD could promote the bone marrow hematopoietic functions in rabbits after hepatectomy via stimulating proliferation of CD34+ cells and shortening the telomere length of CD34+ cells, but the content of HFR was not increased immediately because of the stuck of CD34+ cells in G0/G1 phase.

Analysis of bone marrow aspiration fluid using automated blood cell counters

Cytomorphological examination of aspirate smears remains the basic method to diagnose hematologic disorders and to evaluate treatment-related changes. Last-generation hematological analyzers can count, besides cells normally circulating in peripheral blood, some types of immature and abnormal cells, such as erythroblasts and immature granulocytes. The complex nature of bone marrow fluid, however, has prevented until now the routine utilization of blood cell counters in this area. Recent studies have shown the possibility of using bone marrow fluid as a substitute for peripheral blood for clinical tests in particular situations and for repetitive cytologic examinations in specific clinical and research fields.

Effect of hydroxyurea on immature reticulocyte fraction in sickle cell anemia

Immature reticulocyte fraction (IRF) is a good indicator of bone marrow erythropoiesis in response to hemolysis or tissue hypoxia and is markedly increased in sickle cell disease (SS). We compared IRF changes in SS patients with those who were treated with hydroxyurea (SS-HU), and those who had concurrent alpha globin gene deletion (SS-(- deletion). Forty-two patients including 16 SS, 16 SS-HU, and 10 SS-alpha-deletion patients were studied. Significant decreases (P <.01) in reticulocyte indices including IRF, the reticulocyte percentage, and absolute reticulocyte count (ARC) were observed in SS-alpha-deletion compared to SS patients. On the other hand, although the reticulocyte percentage (P <.01) and ARC (P <.01) were significantly decreased in SS-HU compared with SS patients, the IRF was persistently elevated in both groups (P = .4), suggesting continuous bone marrow stimulation in SS-HU patients in response to tissue hypoxia. The possible underlying physiological mechanisms are discussed.

Pharmacodynamic analysis of time-variant cellular disposition: reticulocyte disposition changes in phlebotomized sheep

Most pharmacodynamic (PD) models of cellular response assume a time-invariant (i.e., constant) cellular disposition despite known changes in the disposition with time, such as the reticulocyte residence time in the systemic circulation during stress erythropoiesis. To account for changes in cellular disposition, a comprehensive PD model that involves endogenous erythropoietin (Epo), reticulocytes, and hemoglobin responses was developed in phlebotomized sheep that considers a time-variant reticulocyte residence time and allows for the simultaneous determination of changes in the cellular disposition and cellular production. Five sheep were phlebotomized to hemoglobin concentrations of approximately 4 g/dl. Epo concentrations, reticulocytes, and hemoglobin concentrations were frequently sampled for 5-7 days prior to and 25-30 days following the phlebotomy. Initial steady-state conditions were assumed and the time-variant reticulocyte residence time in the systemic circulation was semiparametrically represented using a constrained spline function. Hemoglobin production was modeled using a Hill function via an effect site compartment. The initial steady state reticulocyte residence time in the systemic circulation was estimated as 0.477 (0.100) (mean (SD)) days, which maximally increased 2.01- to 2.64-fold higher than the initial steady-state residence time 5.95 (0.899) days post-phlebotomy (P < 0.01). On average, the residence time returned to steady-state values 15.4 (2.36) days post-phlebotomy, which was not significantly different from the initial steady-state value (P > 0.05). The baseline hemoglobin production rate was estimated at 0.0929 (0.0472) g/kg/day and the maximum production rate under stress phlebotomy was estimated at 0.504 (0.0422) g/kg/day. These data indicate that endogenously released Epo under acute anemic conditions can increase hemoglobin production approximately 5-fold. The determined increase in reticulocyte residence time produced under stress erythropoiesis is similar to the commonly reported 2- to 3-fold increase observed in human patients.