Severe congenital neutropenia: abnormal growth and differentiation of myeloid progenitors to granulocyte colony-stimulating factor (G-CSF) but normal response to G-CSF plus stem cell factor

Several mechanisms have been proposed to explain the pathogenesis of severe congenital neutropenia (SCN); however, the mechanism(s) still remains unknown. In particular, clinical observations suggest that abnormal responsiveness of myeloid progenitors to hematopoietic growth factors (HGFs) is a possible mechanism. Therefore, to better define the status of hematopoietic progenitors in the bone marrow (BM) of patients with SCN, the responsiveness of myeloid progenitors to HGFs from two SCN patients was compared with the responsiveness of progenitors from healthy individuals. BM cells (BMCs) from the first SCN patient required higher (10- to 100-fold) concentrations of granulocyte colony- stimulating factor (G-CSF) to achieve maximal and half-maximal colony growth in vitro compared with BMCs from controls. In contrast, the dose- response of interleukin-3 (IL-3) and granulocyte-macrophage-CSF (GM- CSF) in colony formation was normal. Interestingly, IL-3, GM-CSF, and G- CSF at optimal doses showed reduced ability to induce neutrophil differentiation of BMCs from a SCN patient compared with BMCs from controls. Despite an abnormal responsiveness of mature myeloid progenitors to G-CSF in this SCN patient, myeloid progenitors responsive to the combination of stem cell factor (SCF) and G-CSF showed normal dose-response. In contrast to G-CSF alone, the combination of G-CSF and SCF induced the formation of neutrophils almost to the same extent compared with cultures of normal BMCs. Furthermore, also on BM progenitor cells obtained from the second patient with SCN, SCF highly synergized with G-CSF to promote neutrophil progenitor cell growth and differentiation in vitro. Thus, these results indicate that one mechanism of the pathogenesis in SCN patients is reduced responsiveness of neutrophil progenitor cells to G- CSF and that SCF can enhance the responsiveness of these cells to G-CSF.     

Concomitant granulocyte colony-stimulating factor and induction chemoradiotherapy in adult acute lymphoblastic leukemia: a randomized phase III trial

This prospective multicenter study examined whether simultaneous administration of granulocyte colony-stimulating factor (G-CSF; Filgrastim) and induction chemotherapy for adult acute lymphoblastic leukemia (ALL) could prevent treatment-related neutropenia, infections, and resulting treatment delays. Seventy-six patients were randomly assigned to receive either G-CSF (n = 37) or no growth factor (n = 39) in conjunction with a uniform chemotherapy consisting of cyclophosphamide, cytarabine, mercaptopurine, intrathecal methotrexate, and cranial irradiation. The median duration of neutropenia (absolute neutrophil count < 1 x 10(9)/L) during chemotherapy was 8 days in patients receiving C-CSF, compared with 12.5 days in the control group (P < .002). A similar reduction from 11.5 to 7 days was observed in patients with T-ALL receiving additional mediastinal irradiation (P = .13). Infections occurred in 43% and 56% of patients in the G-CSF and control arm, respectively (P = .25); the incidence of nonviral infections was reduced by 50%, from 32 episodes in the control arm to 16 episodes in the G-CSF arm. Prolonged interruptions of chemotherapy administration were less frequent, with delays of 2 weeks or more occurring in only 24% of patients receiving G-CSF as opposed to 46% in the control arm (P = .01). Accordingly, chemotherapy was completed significantly earlier with the use of G-CSF (39 v 44 days, P = .008). With a median follow-up of 20 months, the probability of disease-free survival was 0.45 in the G-CSF group and 0.43 in the control group (P = .34). In conclusion, adult ALL patients appear to benefit by the simultaneous administration of G-CSF with induction chemotherapy because of a significant reduction in the duration of neutropenia, a trend to fewer infections, and a more rapid completion of chemotherapy.     

Steel factor (c-kit ligand) promotes the survival of hematopoietic stem/progenitor cells in the absence of cell division

It is known that the majority of primitive hematopoietic progenitors are in a noncycling quiescent state. In addition, normal hematopoietic progenitors and progenitor cell lines show an absolute dependence on growth factors for their survival in vitro, yet the effect of growth factors on progenitor cell survival has not been separated from effects on both proliferation and differentiation. Using an in vitro assay system, we examined whether growth factors could promote the survival of stem cells in culture in the absence of cell division. These studies show that steel factor (SLF) and, to a lesser extent, interleukin-3 (IL- 3) directly promoted the survival of elutriated bone marrow progenitor cells (countercurrent centrifugal elutriation [CCE]-27) that are enriched for primitive hematopoietic progenitors that respond to the combination of SLF plus IL-3. Furthermore, SLF promoted the survival of short-term reconstituting cells (STRC), and long-term reconstituting cells (LTRC) with trilineage reconstitution potential in vivo. In comparison, granulocyte colony-stimulating factor (G-CSF), IL-6, leukemia inhibitory factor, IL-11, IL-1, granulocyte macrophage CSF (GM- CSF), and macrophage CSF (M-CSF) had no effect on the survival of these cells. In the presence of mitotic inhibitors (nocodazole or aphidicolin), SLF promoted the survival of CCE-27 progenitor cells that respond to the combination of SLF plus IL-3 in vitro and STRCs and LTRCs that are detected in vivo. Taken together, these data show that SLF can directly promote the survival of hematopoietic progenitor cells in the absence of cell division.     

Erythropoietin induces association of the JAK2 protein tyrosine kinase with the erythropoietin receptor in vivo

Protein tyrosine phosphorylation has been hypothesized to play a key role in the growth signaling induced by erythropoietin (Epo), although the Epo receptor (EpoR), a member of the cytokine receptor superfamily, lacks a tyrosine kinase domain. Recently, the JAK2 tyrosine kinase was shown to be activated on Epo stimulation and to bind to the cytoplasmic domain of EpoR in vitro. To further explore the mechanisms of activation of JAK2 in EpoR-mediated signal transduction, we assessed the conditions for association of JAK2 with EpoR in vivo. Epo stimulation rapidly induced association of JAK2 with the EpoR in an interleukin 3 (IL-3)-dependent cell line transfected with the wild-type EpoR. On Epo stimulation JAK2 also associated with a truncated mutant EpoR (H-mutant), which is mitogenetically active but not tyrosine phosphorylated, indicating that association does not require receptor phosphorylation and occurs in the membrane proximal region. However, association was not detected with mutant receptors inactivated by an internal deletion or a point mutation, Trp282 to Arg, in a membrane- proximal cytoplasmic region (PB or PM4 mutant, respectively). Immune complex kinase assays of anti-EpoR immunoprecipitates also revealed that activated JAK2 associates with the EpoR in Epo-stimulated cells. By this approach, association also occurred with the mitogenically active H mutant but not with the mitogenically inactive PB or PM4 mutants. In the immune complex kinases assays, EpoR, JAK2, and a 150-kD protein were phosphorylated on tyrosine. Taken together, the results further support the hypothesis that, on Epo stimulation, JAK2 associates with the membrane-proximal cytoplasmic region of the EpoR to be activated and induces tyrosine phosphorylation of cellular substrates, including the EpoR, to transduce a growth signal.     

Tumor necrosis factor-alpha (TNF-alpha) potently enhances in vitro macrophage production from primitive murine hematopoietic progenitor cells in combination with stem cell factor and interleukin-7: novel stimulatory role of p55 TNF receptors

Tumor necrosis factor-alpha (TNF-alpha) is a bifunctional regulator of hematopoiesis, and its cellular responses are mediated by two distinct cell surface receptors. TNF-alpha generally inhibits the growth of primitive murine hematopoietic progenitor cells (Lin-Scal+) in response to multiple cytokine combinations, and the p75 TNF receptor is essential in signaling such inhibition. In the present study we show the reverse phenomenon in that TNF-alpha on the same progenitor cell population in combination with stem cell factor (SCF) and interleukin-7 (IL-7) through the p55 TNF receptor can recruit additional progenitors to proliferate. In contrast, TGF-beta 1, another bifunctional regulator of hematopoietic progenitor cell growth, completely blocked SCF plus IL- 7-induced proliferation. TNF-alpha increased the number of responding progenitors, as well as the size of the colonies formed. The synergistic effects of TNF-alpha were seen at the single cell level, suggesting that its effects are directly mediated. Finally, whereas SCF plus IL-7 promoted primarily granulopoiesis, the addition of TNF-alpha switched the differentiation toward the production of almost exclusively macrophages.     

Association between intrauterine growth restriction and patent ductus arteriosus: Use of a dichorionic twin pregnancy model

ObjectiveTo evaluate the association between intrauterine growth restriction (IUGR) and the incidence of fetuses with patent ductus arteriosus (PDA) and Hemodynamically significant PDA (Hs-PDA) in dichorionic twins (DC) with selective IUGR.Materials and methodsThis is an observational cohort study and retrospective case assessment, involved twins born at Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan between 2013 and 2018. DC twins with selective IUGR (sIUGR) were defined as the presence of a birth weight discordance of >25% and a smaller twin with a birth weight below the tenth percentile. PDA was diagnosed using echocardiography between postnatal day 3 and 7. Hs-PDA was defined as PDA plus increased pulmonary circulation, poor systemic perfusion, cardiomegaly, pulmonary edema, or hypotension requiring pharmacotherapeutic intervention.ResultA total of 1187 twins were delivered during the study period, and 53 DC twins with selective IUGR were included in this study. DC twins with PDA have higher rate of preterm birth, lower gestational age of delivery, and lower mean birth weight of both twins compared with DC twins without PDA. In a comparison of the sIUGR twin with the appropriate for gestational age co-twin, both the incidences of PDA (28.30% vs. 7.55%, respectively; P = 0.003) and Hs-PDA (24.53% vs. 5.66%, respectively; P = 0.002) were higher in sIUGR fetuses than in the appropriate for gestational age co-twins. Small gestational age of delivery was the only variable to predict PDA and Hs-PDA [p = 0.002, Odds ratio = 0.57 (0.39–0.82), p = 0.009, Odds ratio = 0.71 (0.55–0.92), respectively].ConclusionAn analysis of dichorionic twins with sIUGR indicated that IUGR increased the risk of PDA and hemodynamically significant PDA.     

Malnutrition is independently associated with skin tears in hospital inpatient setting—Findings of a 6‐year point prevalence audit

Skin tears cause pain, increased length of stay, increased costs, and reduced quality of life. Minimal research reports the association between skin tears, and malnutrition using robust measures of nutritional status. This study aimed to articulate the association between malnutrition and skin tears in hospital inpatients using a yearly point prevalence of inpatients included in the Queensland Patient Safety Bedside Audit, malnutrition audits and skin tear audits conducted at a metropolitan tertiary hospital between 2010 and 2015. Patients were excluded if admitted to mental health wards or were <18 years. A total of 2197 inpatients were included, with a median age of 71 years. The overall prevalence of skin tears was 8.1%. Malnutrition prevalence was 33.5%. Univariate analysis demonstrated associations between age (P ˂ .001), body mass index (BMI) (P < .001) and malnutrition (P ˂ .001) but not gender (P = .319). Binomial logistic regression analysis modelling demonstrated that malnutrition diagnosed using the Subjective Global Assessment was independently associated with skin tear incidence (odds ratio, OR: 1.63; 95% confidence interval, CI: 1.13‐2.36) and multiple skin tears (OR 2.48 [95% CI 1.37‐4.50]). BMI was not independently associated with skin tears or multiple skin tears. This study demonstrated independent associations between malnutrition and skin tear prevalence and multiple skin tears. It also demonstrated the limitations of BMI as a nutritional assessment measure.     

The Nutritional Quality of Kids’ Menus from Cafés and Restaurants: An Australian Cross-Sectional Study

Australian families increasingly rely on eating foods from outside the home, which increases intake of energy-dense nutrient-poor foods. ‘Kids’ Menus’ are designed to appeal to families and typically lack healthy options. However, the nutritional quality of Kids’ Menus from cafes and full-service restaurants (as opposed to fast-food outlets) has not been investigated in Australia. The aim of this study was to evaluate the nutritional quality of Kids’ Menus in restaurants and cafés in metropolitan Perth, Western Australia. All 787 cafes and restaurants located within the East Metropolitan Health Service area were contacted and 33% had a separate Kids’ Menu. The validated Kids’ Menu Healthy Score (KIMEHS) was used to assess the nutritional quality of the Kids’ Menus. Almost all Kids’ Menus (99%) were rated ‘unhealthy’ using KIMEHS. The mean KIMEHS score for all restaurants and cafés was −8.5 (range −14.5 to +3.5) which was lower (i.e., more unhealthy) than the mean KIMEHS score for the top 10 most frequented chain fast-food outlets (mean −3.5, range −6.5 to +3). The findings highlight the need for additional supports to make improvements in the nutritional quality of Kids’ Menus. Local Government Public Health Plans provide an opportunity for policy interventions, using locally relevant tools to guide decision making.