Postmitotic Pool Research Articles

Novel properties of statins: suppression of the systemic and bone marrow responses induced by exposure to ambient particulate matter (PM10) air pollution

Exposure to ambient particulate matter (PM(10) elicits systemic inflammatory responses that include the stimulation of bone marrow and progression of atherosclerosis. The present study was designed to assess the effect of repeated exposure of PM(10) on the turnover and release of polymorphonuclear leukocytes (PMNs) from the bone marrow into the circulation and the effect of lovastatin on the PM(10)-induced bone marrow stimulation. Rabbits exposed to PM(10)three times a week for 3 wk, were given a bolus of 5'-bromo-2'-deoxyuridine to label dividing cells in the marrow to calculate the transit time of PMNs in the mitotic or postmitotic pool. PM(10) exposure accelerated the turnover of PMNs by shortening their transit time through the marrow (64.8 ± 1.9 h vs. 34.3 ± 7.4 h, P < 0.001, control vs. PM(10)). This was predominantly due to a rapid transit of PMNs through the postmitotic pool (47.9 ± 0.7 h vs. 21.3 ± 4.3 h, P < 0.001, control vs. PM(10)) but not through the mitotic pool. Lovastatin delayed the transit time of postmitotic PMNs (38.2 ± 0.5 h, P < 0.001 vs. PM(10)) and shifted the postmitotic PMN release peak from 30 h to 48 h. PM(10) exposure induced the prolonged retention of newly released PMNs in the lung, which was reduced by lovastatin (P < 0.01). PM(10) exposure increased plasma interleukin-6 levels with significant reduction by lovastatin (P < 0.01). We conclude that lovastatin downregulates the PM(10)-induced overactive bone marrow by attenuating PM(10)-induced systemic inflammatory responses.

Specific features of satellite cells and myoblasts at different stages of rat postnatal development

A cell culture consisting mainly of satellite cells and mononuclear myoblasts was derived from femoral muscles of infant (aged 3-7 days) and adult rats. Satellite cells identified by expression of the specific marker Pax7 accounted for approximately 80% of the isolated cell fraction. Mononuclear myoblasts represented by proliferating and postmitotic cell pools were identified immunocytochemically by the expression of markers Ki67 and desmin. Differentiation of satellite cells and myoblasts in the culture depended on the concentration of Ca2+ in the culture medium (F12 with different Ca2+ concentrations or DMEM). Differentiation of myogenic cells manifested in myoblasts fusion, formation of myotubes, and expression of myosin in myofibrils was observed only in the medium with a high Ca2+ concentration (2 mM). Satellite cells and myoblasts from the muscles of newborn and adult rats did not differ noticeably in their capacity for differentiation.

Release of band cells from the bone marrow is impaired by preoperative chemoradiation in patients with esophageal carcinoma: increased risk of postoperative pneumonia

To examine the difference in hematological data and postsurgical course after esophagectomy between patients receiving preoperative chemoradiation and patients without preoperative treatment. Twenty-two patients with squamous cell carcinoma of the esophagus who underwent esophagectomy during the past 2 years were retrospectively analyzed in the study. Six patients had preoperative chemoradiation (CRT group) and 16 patients had no preoperative treatment (non-CRT group). The hematological data, postoperative course, and surgical complications were compared between the two groups. Patients in the CRT group were given cisplatin and 5-FU (143 and 6,000 mg on average, respectively) plus an average of 35 Gy of radiation. Although the neutrophil count did not show a significant difference between the two groups, the band cell count was lower in the CRT group compared with the non-CRT group on postoperative day 1 (P<0.05). Postoperative pneumonia was detected in three patients (50%) from the CRT group versus none of the non-CRT group. Preoperative CRT may be a risk factor for postoperative pneumonia in patients with esophageal carcinoma who undergo esophagectomy. The normal bone marrow response of releasing band cells from the postmitotic marrow pool after surgery could be disturbed by CRT, which might contribute to an increase in later pulmonary complications.

Evaluation of role of G-CSF in the production, survival, and release of neutrophils from bone marrow into circulation

AbstractIn steady-state hematopoiesis, G-CSF (granulocyte-colony stimulating factor) regulates the level of neutrophils in the bone marrow and blood. In this study, we have exploited the availability of G-CSF–deficient mice to evaluate the role of G-CSF in steady-state granulopoiesis and the release of granulocytes from marrow into circulation. The thymidine analogue bromodeoxyuridine (BrdU) was used to label dividing bone marrow cells, allowing us to follow the release of granulocytes into circulation. Interestingly, the labeling index and the amount of BrdU incorporated by blast cells in bone marrow was greater in G-CSF–deficient mice than in wild-type mice. In blood, 2 different populations of BrdU-positive granulocytes, BrdUbright and BrdUdim, could be detected. The kinetics of release of the BrdUbright granulocytes from bone marrow into blood was similar in wild-type and G-CSF–deficient mice; however, BrdUdim granulocytes peaked earlier in G-CSF–deficient mice. Our findings suggest that the mean transit time of granulocytes through the postmitotic pool is similar in G-CSF–deficient and control mice, although the transit time through the mitotic pool is reduced in G-CSF–deficient mice. Moreover, the reduced numbers of granulocytes that characterize G-CSF–deficient mice is primarily due to increased apoptosis in cells within the granulocytic lineage. Collectively, our data suggest that at steady state, G-CSF is critical for the survival of granulocytic cells; however, it is dispensable for trafficking of granulocytes from bone marrow into circulation.

The Effect of Repeated Exposure to Particulate Air Pollution (PM10) on the Bone Marrow

Studies have shown that exposure to ambient particulate matter is related to an increased cardiopulmonary morbidity and mortality. The present study was designed to measure the effect of repeated exposure to urban air particles (PM10) on the rate of production and release of polymorphonuclear leukocytes (PMN) from the bone marrow into the peripheral blood. Rabbits exposed to PM10 (5 mg) twice a week for 3 wk, were given a bolus of 5'-bromo-2'-deoxyuridine (BrdU) to label dividing cells in the marrow that allows us to calculate the transit time of PMN in the bone marrow mitotic and postmitotic pools. The PM10 exposure (n = 8) causes a persistent increase in circulating band cells (p < 0.05) and a shortening of the transit time of PMN through the postmitotic pool in the marrow (64.4 +/- 2.2 h to 56.3 +/- 2.2 h, p < 0.05) if compared with vehicle-exposed control subjects (n = 6). PM10 exposure increases the bone marrow pool of PMN particularly the mitotic pool of PMN (p < 0.05). The PM10 were distributed diffusely in the lung and caused a mild mononuclear inflammation. The percentage of alveolar macrophages containing PM10 correlated significantly with the bone marrow PMN pool size (total pool r2 = 0.56, p < 0.012, mitotic pool r2 = 0.61, p < 0.007) and the transit time of PMN through the postmitotic pool (r2 = -0.42, p < 0.043). We conclude that repeated exposure to PM10 stimulates the bone marrow to increase the production of PMN in the marrow and accelerate the release of more immature PMN into the circulation. The magnitude of these changes was related to the amount of particles phagocytosed by alveolar macrophages.

Interleukin-6 induces demargination of intravascular neutrophils and shortens their transit in marrow.

Recombinant human interleukin-6 (IL-6) causes both a thrombocytosis and leukocytosis. The thrombocytosis is caused by an accelerating thrombocytopoiesis, but the mechanism of the leukocytosis is unknown. This study was designed to determine the relative contributions of marrow stimulation and intravascular demargination to the IL-6 induced neutrophilia. IL-6 (2 microgram/kg), administered intravenously to rabbits, caused a biphasic neutrophilia with an initial peak at 3 h and a second peak at 9 h. Using the thymidine analog 5'-bromo-2'-deoxyuridine (BrdU) to label dividing polymorphonuclear leukocytes (PMNs) in the bone marrow, we showed that IL-6 treatment mobilizes PMNs from the marginated pool into the circulating pool at 2-6 h with a decrease in L-selectin expression on PMNs and also accelerates the release of PMNs from the postmitotic pool in the bone marrow at 12-24 h. We have concluded that IL-6 causes a biphasic neutrophilia wherein the first peak results from the mobilization of PMNs into the circulating pool from the marginated pool and the second peak results from an accelerated bone marrow release of PMNs.

Granulocyte-colony stimulating factor is not critical for mobilisation of granulocytes from bone marrow into circulation

In normal steady-state hematopoiesis, G-CSF not only regulates the production of neutrophils, it is also involved in release of neutrophil from bone marrow into the circulation. In the present study we have evaluated the physiological role of G-CSF in the release of granulocytes from marrow into circulation. The thymidine analogue, 5′-bromo-2′-deoxyuridine (BrdU), was used to label dividing bone marrow cells and follow the release of granulocytes into circulation in G-CSF-deficient and wild type mice. The bone marrow and blood cells were labeled with anti-BrdU antibody conjugated to FITC and anti-Gr-1 antibody conjugated to PE (marker for granulocytes) and analysed by FACScan. Interestingly, the labeling index and the amount of BrdU incorporated by bone marrow cells was greater in G-CSF-deficient mice compared to wild type mice. This phenomenon was most striking in the blast cell population clearly indicating that this population of cells is cycling faster in G-CSF-deficient mice compared to wild type mice. However, a greater proportion of early granulocytic cells in the bone marrow was undergoing apoptosis in G-CSF-deficient mice compared to wild type mice. The kinetics of release of granulocytes from marrow into circulation was similar in both G-CSF and wild type mice. Similarly, the transit time of granulocytes through the mitotic and post-mitotic pool in the marrow was unaffected in absence of G-CSF. Furthermore, the peripheral half-lives of granulocytes of G-CSF-deficient and wild-type mice were comparable. These findings demonstrate that while G-CSF is important for survival of granulocytic cells, under physiological conditions, G-CSF is dispensable for mobilisation of granulocytes from marrow into circulation.

Polymorphonuclear leukocytes released from the bone marrow by granulocyte colony-stimulating factor: intravascular behavior.

Granulocyte-colony stimulating factor (G-CSF) treatment stimulates the bone marrow and releases polymorphonuclear leukocytes (PMN) into the circulation. This study was designed to measure the intravascular margination, demargination and survival of PMN released from the marrow by G-CSF. To trace PMN in the circulation, dividing PMN in the bone marrow of rabbits were labeled with 5'-bromo-2'-deoxyuridine (BrdU) and the effects of a single dose of G-CSF (12.5 microg/kg) on the behavior of these labeled cells in the circulation were measured. The results show that G-CSF induced a granulocytosis that peaked 12 h after treatment. This granulocytosis was associated with stimulation of the bone marrow characterized by shortening of the transit time of PMN through the marrow (97.3+/-2.5 h n=4 control vs 78.9+/-3.6 h n=5 G-CSF) particularly in the post-mitotic pool (P<0.01). Morphometric studies of the lung show a reduced sequestration of BrdU-labeled PMN in lung microvessels in G-CSF-treated animals (P<0.05) and a approximately 14-fold (G-CSF-group) vs a approximately 65-fold (control-group) enrichment of BrdU-labeled PMN in lung tissue if compared to circulating blood. The effect of G-CSF on demargination of PMN was measured by transferring BrdU-labeled PMN from donor animals treated with G-CSF to recipients. G-CSF did not cause demargination of intravascular PMN but delayed the clearance of G-CSF-treated PMN in the circulation. This delayed clearance was associated with inhibition of apoptosis in circulating PMN when measured both by morphology (17.7+/-2.3 vs 7.5+/-1.4%, P<0.01) and flow cytometry (16.2+/-1.1 vs 5+/-1.9%, P<0.01) using a DNA end-labeling method (control vs G-CSF group). We conclude that PMN released from the bone marrow by G-CSF sequestered less in the lung microvessels and have a prolonged intravascular life span.

Cigarette smoking causes sequestration of polymorphonuclear leukocytes released from the bone marrow in lung microvessels.

Studies from our laboratory have shown that chronic cigarette smoke exposure causes a neutrophilia associated with a shortening of the mean transit time of polymorphonuclear leukocytes (PMN) though the postmitotic pool of the marrow. The present study was designed to test the hypothesis that PMN newly released from bone marrow by smoke exposure preferentially sequestered in pulmonary microvessels. The thymidine analogue 5'-bromo-2'-deoxyuridine (BrdU) was used to label dividing PMN in the marrow of rabbits; their appearance in the circulation was measured using immunocytochemistry, and their sequestration in lung tissue was determined using standard morphometric techniques. Animals exposed to 11 d of cigarette smoke (n = 6) compared with sham-exposed control animals (n = 4) showed no increase in circulating PMN counts but showed an increase in both the percentage of band cells (smoking, 9.8 +/- 1.1% versus control, 5.5 +/- 0.9%; P < 0.05) and BrdU-labeled PMN (PMNBrdU) in the circulation (smoking, 10.8 +/- 0.6% versus control, 7.5 +/- 0.3%; P < 0.05). There were more PMN sequestered in the lungs of smoke-exposed animals (51.7 +/- 3.4 x 10(7)/ml tissue) than in those of control animals (25.1 +/- 1.8 x 10(7)/ ml tissue) (P < 0.05) and a higher percentage of these cells were PMNBrdU (smoking, 16.9 +/- 2. 3% versus control, 9.6 +/- 0.4%; P < 0.05). The percentage of PMNBrdU in the gravity-independent regions (11.7 +/- 1.9%) of the lung was higher than gravity-dependent regions (7.8 +/- 1.8%) in the smoke-exposure group (P < 0.05). Transmission electron microscopy showed pulmonary capillary endothelial damage with adherent PMN in the smoke-exposure group. We conclude that younger PMN released from the bone marrow by cigarette smoking preferentially sequestered in pulmonary microvessels and speculate that these PMN may contribute to the alveolar wall damage associated with smoke-induced lung emphysema.

Glucocorticoid-induced granulocytosis: contribution of marrow release and demargination of intravascular granulocytes.

Glucocorticoid-induced granulocytosis has been attributed to enhanced release of polymorphonuclear leukocytes (PMNs) from bone marrow, delayed apoptosis, and reduced egress of PMNs into tissues. This study was designed to determine the relative contributions of PMNs released from the bone marrow and those entering the circulation from the marginated pool to the granulocytosis produced by a single dose of dexamethasone (2.0 mg/kg) in rabbits. PMN transit through the mitotic and postmitotic pools of the bone marrow and rate of release of PMNs into the circulation were measured by use of the thymidine analogue 5'-bromo-2'-deoxyuridine (BrdU) to pulse-label PMNs in the bone marrow. The shift of PMNs from the marginated to the circulating pool was measured with BrdU-labeled PMNs transferred from donor rabbits to recipients before dexamethasone was delivered. The data show that dexamethasone increased bone marrow release of PMNs and shortened their transit time through the postmitotic pool (P<0.001) but not the mitotic pool of the bone marrow (P>0.05). Dexamethasone slowed the clearance of BrdU-labeled PMNs from the circulation (P<0.05) and lengthened their disappearance (half-life) from the circulation compared with control (half-life, 4.95 versus 9. 45 hours). At 6 hours after dexamethasone, bone marrow release contributed approximately 10%, mobilization from the marginated pool approximately 61%, and a lengthened half-life in the circulation approximately 29% to the glucocorticoid-induced granulocytosis. We conclude that a single dose of dexamethasone causes a granulocytosis primarily by a shift of PMNs from the marginated to the circulating pool, with a minor contribution from marrow release.

Release of Polymorphonuclear Leukocytes From the Bone Marrow by Interleukin-8

Several studies have shown that interleukin-8 (IL-8) causes a rapid granulocytosis with the release of polymorphonuclear leukocytes (PMN) from the bone marrow (BM) partially responsible for the granulocytosis. This study was designed to quantitate the release of PMN from the BM by IL-8 and measure the transit time of PMN through the marrow after IL-8 administration. The thymidine analogue, 5'-bromo-2'-deoxyuridine (BrdU), was used to label dividing PMN in the marrow and follow their release into the circulation after intravenous IL-8. This allowed us to calculate the transit time of PMN through the mitotic and postmitotic pools of BM. BrdU was infused intravenously into rabbits 24 hours before IL-8 (2.5 μg/kg). IL-8 caused a rapid, transient granulocytopenia (5.9 ± 0.4 at baseline v 0.2 ± 0.06 × 10/9L at 5 minutes, P &lt; .05) followed by granulocytosis (8.4 ± 0.1 at 30 minutes, P &lt; .05) associated with an increased number (0.3 ± 0.1 at baseline v1.2 ± 0.6 × 109/L at 30 minutes, P &lt; .05) and percentage of band cells (P &lt; .05), as well as a rapid increase in the number of BrdU-labeled PMN (PMNBrdU) in the circulation (0.09 ± 0.05 at baseline to 1.5 ± 0.6 × 109/L at 60 minutes, P &lt; .05). The transit time of PMN through both the mitotic and postmitotic pools of BM was not affected by IL-8. To determine the marrow compartment from which the PMN were mobilized by IL-8, we quantitated PMN movement from the hematopoietic and sinusoidal compartments into the circulation. The fraction of PMNBrdU in both compartments was higher than in the circulating blood (P &lt; .05) and the fraction and number of PMNBrdU in the sinusoids decreased with IL-8 treatment (P &lt; .05). We conclude that the pool of PMN residing in the BM venous sinusoids are rapidly released into the circulation after administration of IL-8.© 1998 by The American Society of Hematology.

Release of Polymorphonuclear Leukocytes From the Bone Marrow by Interleukin-8

AbstractSeveral studies have shown that interleukin-8 (IL-8) causes a rapid granulocytosis with the release of polymorphonuclear leukocytes (PMN) from the bone marrow (BM) partially responsible for the granulocytosis. This study was designed to quantitate the release of PMN from the BM by IL-8 and measure the transit time of PMN through the marrow after IL-8 administration. The thymidine analogue, 5‘-bromo-2‘-deoxyuridine (BrdU), was used to label dividing PMN in the marrow and follow their release into the circulation after intravenous IL-8. This allowed us to calculate the transit time of PMN through the mitotic and postmitotic pools of BM. BrdU was infused intravenously into rabbits 24 hours before IL-8 (2.5 μg/kg). IL-8 caused a rapid, transient granulocytopenia (5.9 ± 0.4 at baseline v 0.2 ± 0.06 × 10/9L at 5 minutes, P < .05) followed by granulocytosis (8.4 ± 0.1 at 30 minutes, P < .05) associated with an increased number (0.3 ± 0.1 at baseline v1.2 ± 0.6 × 109/L at 30 minutes, P < .05) and percentage of band cells (P < .05), as well as a rapid increase in the number of BrdU-labeled PMN (PMNBrdU) in the circulation (0.09 ± 0.05 at baseline to 1.5 ± 0.6 × 109/L at 60 minutes, P < .05). The transit time of PMN through both the mitotic and postmitotic pools of BM was not affected by IL-8. To determine the marrow compartment from which the PMN were mobilized by IL-8, we quantitated PMN movement from the hematopoietic and sinusoidal compartments into the circulation. The fraction of PMNBrdU in both compartments was higher than in the circulating blood (P < .05) and the fraction and number of PMNBrdU in the sinusoids decreased with IL-8 treatment (P < .05). We conclude that the pool of PMN residing in the BM venous sinusoids are rapidly released into the circulation after administration of IL-8.© 1998 by The American Society of Hematology.

Effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) on neutrophil kinetics and function in normal human volunteers.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) (250 microg/m2) was administered subcutaneously to 7 normal volunteers for up to 14 days to study its effects on neutrophil kinetics and function. With treatment, blood neutrophil counts rose gradually to peak at 3 1/2 times baseline by day 14. At day 5 marrow mitotic cells were increased and post-mitotic cells decreased, and the transit time through the post-mitotic marrow pool accelerated (normal = 6.4 days, GM-CSF = 3.9 days; P < 0.01). Treatment had little effect on the blood neutrophil half-life (normal = 9.6 +/- 1.3 hours; GM-CSF = 13.1 +/- 2.4 hours, P > 0.05); or the neutrophil turnover rate (normal = 78.5 +/- 11.9 x 10(7)/cells/kg/day, GM-CSF = 91.4 +/- 19.8 x 10(7)/cells/kg/day, P > 0.05). GM-CSF reduced the number of neutrophils migrating to skin chambers (normal = 104 +/- 25.0 x 10(6)/cells, GM-CSF = 48.6 +/- 16.0 x 10(6)/cells; P < 0.05). Treatment increased expression of CD11b/CD18 but not Fcgamma receptors (CD16, CD32, CD64). Treatment also stimulated the in vitro neutrophil respiratory burst in response to a variety of agonists, and this enhancement persisted for the duration of treatment. All subjects experienced local and systemic adverse effects and developed eosinophilia. This study indicates that GM-CSF at a dose of 250 microg/m2 causes neutrophilia chiefly by accelerating delivery of neutrophils from the marrow to the blood and by decreasing migration from the blood to the tissues, with only a modest effect on neutrophil production and blood half-life.

The effect of cigarette smoking on the bone marrow.

Chronic cigarette smoking produces a 20 to 25% increase in the number of peripheral blood leukocytes, and there is increasing evidence that these leukocytes are activated in the lung by the inhalation of cigarette smoke. The present study was designed to measure the effect of cigarette smoke inhalation on the rate of production and release of polymorphonuclear leukocytes (PMN) from the bone marrow into the peripheral blood. The thymidine analogue 5'-bromo-2'-deoxyuridine (BrdU) was used to pulse-label the dividing cells in the marrow of rabbits, measure their appearance in the peripheral blood, and calculate the time that PMN spend in the mitotic and postmitotic pools of the bone marrow. Comparison of animals exposed to 2 wk of cigarette smoke (n = 8) with sham-exposed controls (n = 9) showed that smoking decreased the mean transit time of PMNBrdU through the bone marrow from 97.3 +/- 3.0 h to 89.6 +/- 5.8 h (p < 0.001) by reducing the transit time of PMN in the postmitotic pool from 66.7 +/- 3.9 h to 53.7 +/- 0.7 h (p < 0.001). Both the mitotic (p < 0.05) and postmitotic (p < 0.05) pools of PMN increased in size following cigarette-smoke exposure. We conclude that chronic cigarette smoking stimulates the bone marrow, increases the size of the mitotic and postmitotic pools of PMN, and reduces the time PMN spend in the postmitotic pool in the marrow. These changes may contribute to the leukocytosis seen in cigarette smokers.

Polymorphonuclear leukocyte transit times in bone marrow during streptococcal pneumonia.

The release of polymorphonuclear leukocytes (PMN) from the bone marrow (BM) is a hallmark of acute inflammatory conditions. BM stimulation may increase the toxic potential of these newly released PMN and influence their behavior at inflammatory sites. The present study was designed to measure the transit time of PMN in the mitotic and postmitotic pools of the BM in rabbit using 5'-bromo-2'-deoxyuridine (BrdU). Blood samples were obtained at 2- to 24-h intervals from 24 to 192 h after a single BrdU injection, and BrdU-positive PMN (PMNBrdU) was detected as they appear in the circulating blood, using immunohistochemistry. The intensity of nuclear staining for BrdU was used to define a single generation of PMN and graded as either weakly (G1), moderately (G2), or highly (G3) stained. The mean +/- SE transit time of PMNBrdU through the BM was 95.6 +/- 3.6 h, with 51.1 +/- 5.9 h in the mitotic and 65.4 +/- 5.4 h in the postmitotic pool. Streptococcus pneumoniae instillation in the lung (n = 3) shortened the transit time of PMN through the BM to 54.0 +/- 2.6 h with a shorter time in both the mitotic (36.2 +/- 5.7 h) and the postmitotic pool 34.6 +/- 0.8 h). All these values were shorter than the control values (P < 0.05). We conclude that Streptococcus pneumoniae shortens the transit time of PMN in the mitotic and postmitotic pools in the marrow, which may result in the release of immature PMN with higher levels of lysosomal enzymes into the circulation.

Effect of recombinant granulocyte colony-stimulating factor on neutrophil kinetics in normal young and elderly humans

Recombinant granulocyte colony-stimulating factor (G-CSF) was administered to healthy young (n = 32) and elderly (n = 19) volunteers (0 microgram/d, 30 microgram/d, or 300 microgram/d) to determine its effect on neutrophil production, blood kinetics, and tissue migration. Measurements included blood counts (daily), marrow neutrophil pool sizes and neutrophil tissue migration (baseline and day 5), blood kinetics (day 6), and marrow transit time while on drug (days 6 to 14). G-CSF markedly expanded the marrow neutrophil mitotic pool and shortened the transit time of the postmitotic pool (control, mean = 6.4 days; 300 microgram/d, mean = 2.9 d). G-CSF increased neutrophil production without significantly altering blood neutrophil half-life or margination. Compared to control, neutrophil accumulation in skin chambers decreased by about 50% in the 300 microgram/d group in both young and elderly subjects. G-CSF induced neutrophilia by stimulating proliferation of marrow neutrophil precursors and accelerating neutrophil entry into the blood. Decreased neutrophil inflammatory responses measured with the skin chamber technique may be because of the relative immaturity of the circulating cells or to alterations in neutrophil phenotype induced by G-CSF.

Effect of recombinant granulocyte colony-stimulating factor on neutrophil kinetics in normal young and elderly humans

Abstract Recombinant granulocyte colony-stimulating factor (G-CSF) was administered to healthy young (n = 32) and elderly (n = 19) volunteers (0 microgram/d, 30 microgram/d, or 300 microgram/d) to determine its effect on neutrophil production, blood kinetics, and tissue migration. Measurements included blood counts (daily), marrow neutrophil pool sizes and neutrophil tissue migration (baseline and day 5), blood kinetics (day 6), and marrow transit time while on drug (days 6 to 14). G-CSF markedly expanded the marrow neutrophil mitotic pool and shortened the transit time of the postmitotic pool (control, mean = 6.4 days; 300 microgram/d, mean = 2.9 d). G-CSF increased neutrophil production without significantly altering blood neutrophil half-life or margination. Compared to control, neutrophil accumulation in skin chambers decreased by about 50% in the 300 microgram/d group in both young and elderly subjects. G-CSF induced neutrophilia by stimulating proliferation of marrow neutrophil precursors and accelerating neutrophil entry into the blood. Decreased neutrophil inflammatory responses measured with the skin chamber technique may be because of the relative immaturity of the circulating cells or to alterations in neutrophil phenotype induced by G-CSF.

The uptake of etiocholanolone by human bone marrow immature granulocytes.

A cell fraction enriched in immature granulocytes was obtained after fractionation of human bone marrow by a three-step procedure. This fraction sediments at an average density of 1.073 and has a high content of myelocytes and metamyelocytes. It showed the highest specific uptake of etiocholanolone when compared to other bone marrow cell fractions. Autoradiographic studies demonstrated a higher number of silver grains over myelocytes and metamyelocytes than in other cell types. These results suggest the presence in human bone marrow of a target cell for etiocholanolone, located in the late mitotic or postmitotic pool or granulocytes.

Neutrophil kinetics in chronic neutropenia

Quantitative studies of bone marrow neutrophil pool sizes and production rates and of blood neutrophil kinetics were performed in 16 patients with chronic neutropenia without splenomegaly. Marrow netrophil cellularity was determined from a ferrokinetic estimate of marrow normoblasts and from neutrophil-erythroid ratios determined from marrow sections. Postmitotic pool turnover was derived from the postmitotic pool size and transit time, the latter determined from 3H-thymidine neutrophil emergence time. Blood neutrophil kinetics were studied with 32P-diisopropylfluoophosphate-labeled autologous neutrophils. Mitotic pool size was basal or below basal in 12 of the 16 patients. The turnover of the post-mitotic neutrophils was subbasal in 6, basal in 7, and above basal in 3 patients. Blood neutrophil turnover was within the normal range in 8 patients and decreased in 8. The degree of ineffective granulocytopoiesis was assessed by comparing the relative size of the mitotic pool, postmitotic pool turnover, and blood turnover. On this basis, 13 of the 16 patients showed appreciable degrees of ineffective granulocytopoiesis. Ineffective neutrophil production occurred both early and late in neutrophil development. These studies indicate that most patients with chronic neutropenia without splenomegaly lack a proliferative marrow response to the neutropenia and suggest that ineffective granulocytopoiesis is a common feature of this disorder.

Neutrophil Kinetics in Chronic Neutropenia

AbstractQuantitative studies of bone marrow neutrophil pool sizes and production rates and of blood neutrophil kinetics were performed in 16 patients with chronic neutropenia without splenomegaly. Marrow neutrophil cellularity was determined from a ferrokinetic estimate of marrow normoblasts and from neutrophil–erythroid ratios determined from marrow sections. Postmitotic pool turnover was derived from the postmitotic pool size and transit time, the latter determined from 3H-thymidine neutrophil emergence time. Blood neutrophil kinetics were studied with 32P-diisopropylfluorophosphate-labeled autologous neutrophils. Mitotic pool size was basal or below basal in 12 of the 16 patients. The turnover of the postmitotic neutrophils was subbasal in 6, basal in 7. and above basal in 3 patients. Blood neutrophil turnover was within the normal range in 8 patients and decreased in 8. The degree of ineffective granulocytopoiesis was assessed by comparing the relative size of the mitotic pool, postmitotic pool turnover, and blood turnover. On this basis, 13 of the 16 patients showed appreciable degrees of ineffective granulocytopoiesis. Ineffective neutrophil production occurred both early and late in neutrophil development. These studies indicate that most patients with chronic neutropenia without splenomegaly lack a proliferative marrow response to the neutropenia and suggest that ineffective granulocytopoiesis is a common feature of this disorder.