Abnormal erythropoiesis and the pathophysiology of chronic anemia

Multiple Infections, Nutrient Deficiencies, and Inflammation as Determinants of Anemia and Iron Status during Pregnancy: The MINDI Cohort

In pregnant women with multiple infections, nutrient deficiencies, and inflammation (MINDI), the study of anemia and iron status is limited. For this cross-sectional study (n = 213 Panamanian indigenous women), we investigated if hemoglobin, anemia (Hb < 110 g/L), ferritin, serum iron, serum transferrin receptor, and hepcidin were associated with (1) maternal nutritional status and supplementation practices, (2) biomarkers of inflammation, and (3) presence/absence of infections. Hierarchical generalized linear and logistic regression models and dominance analyses identified the relative importance of these predictors. Anemia (38%), which was likely underestimated due to low plasma volume (95%), was associated with lower ferritin, vitamin A, and weight-for-height, suggesting anemia of undernutrition. Inflammation was not associated with Hb or anemia; nevertheless, higher CRP was associated with increased odds of low serum iron and higher ferritin and hepcidin, indicating iron restriction due to inflammation. The length of iron supplementation did not enter models for anemia or iron indicators, but a multiple nutrient supplement was associated with higher ferritin and hepcidin. Moreover, iron supplementation was associated with higher odds of vaginal trichomoniasis but lower odds of caries and bacterial vaginosis. The complex pathogenesis of anemia and iron deficiency in MINDI settings may require other interventions beyond iron supplementation.

The miR-144/Hmgn2 regulatory axis orchestrates chromatin organization during erythropoiesis

Differentiation of stem and progenitor cells is a highly regulated process that involves the coordinated action of multiple layers of regulation. Here we show how the post-transcriptional regulatory layer instructs the level of chromatin regulation via miR-144 and its targets to orchestrate chromatin condensation during erythropoiesis. The loss of miR-144 leads to impaired chromatin condensation during erythrocyte maturation. Among the several targets of miR-144 that influence chromatin organization, the miR-144-dependent regulation of Hmgn2 is conserved from fish to humans. Our genetic probing of the miR-144/Hmgn2 regulatory axis establish that intact miR-144 target sites in the Hmgn2 3'UTR are necessary for the proper maturation of erythrocytes in both zebrafish and human iPSC-derived erythroid cells while loss of Hmgn2 rescues in part the miR-144 null phenotype. Altogether, our results uncover miR-144 and its target Hmgn2 as the backbone of the genetic regulatory circuit that controls the terminal differentiation of erythrocytes in vertebrates.

Macrocytic anemias

PURPOSE OF REVIEW

Over the last century, the diseases associated with macrocytic anemia have been changing with more patients currently having hematological diseases including malignancies and myelodysplastic syndrome. The intracellular mechanisms underlying the development of anemia with macrocytosis can help in understanding normal erythropoiesis. Adaptations to these diseases involving erythroid progenitor and precursor cells lead to production of fewer but larger red blood cells, and understanding these mechanisms can provide information for possible treatments.

RECENT FINDINGS

Both inherited and acquired bone marrow diseases involving primarily impaired or delayed erythroid cell division or secondary adaptions to basic erythroid cellular deficits that results in prolonged cell division frequently present with macrocytic anemia.

SUMMARY OF FINDINGS

In marrow failure diseases, large accumulations of iron and heme in early stages of erythroid differentiation make cells in those stages especially susceptible to death, but the erythroid cells that can survive the early stages of terminal differentiation yield fewer but larger erythrocytes that are recognized clinically as macrocytic anemia. Other disorders that limit deoxynucleosides required for DNA synthesis affect a broader range of erythropoietic cells, but they also lead to macrocytic anemia. The source of macrocytosis in other diseases remains uncertain.

The miR-144/Hmgn2 regulatory axis orchestrates chromatin organization during erythropoiesis

Differentiation of stem and progenitor cells is a highly regulated process that involves the coordinated action of multiple layers of regulation. Here we show how the post-transcriptional regulatory layer instructs the level of chromatin regulation via miR-144 and its targets to orchestrate chromatin condensation during erythropoiesis. The loss of miR-144 leads to impaired chromatin condensation during erythrocyte maturation. Among the several targets of miR-144 that influence chromatin organization, the miR-144-dependent regulation of Hmgn2 is conserved from fish to humans. Our genetic probing of the miR-144/Hmgn2 regulatory axis established that intact miR-144 target sites in the Hmgn2 3'UTR are necessary for the proper maturation of erythrocytes in both zebrafish and human iPSC-derived erythroid cells while loss of Hmgn2 rescues in part the miR-144 null phenotype. Altogether, our results uncover miR-144 and its target Hmgn2 as the backbone of the genetic regulatory circuit that controls the terminal differentiation of erythrocytes in vertebrates.

Arsenic exposure is associated with alterations to multiple red blood cell parameters among adults in rural Bangladesh

Chronic arsenic exposures are associated with multiple hematologic disturbances, including anemia. The goal of this study was to evaluate associations between arsenic exposures and hematological parameters among men and women who are chronically exposed to elevated levels of arsenic from drinking water. Hematologic analyses were performed on blood collected from 755 participants (45% male and 54% female) in the Health Effects of Arsenic Longitudinal Study (HEALS) cohort, Bangladesh. Herein, we used linear regression models to estimate associations between red blood cell (RBC) parameters (i.e., RBC counts, hematocrit (HCT), hemoglobin (Hgb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC)) and measurements of arsenic exposure (urinary arsenic and urinary arsenic metabolites). Arsenic exposures showed trending associations with decreased RBC counts in both men and women, a positive association with MCV in males, and an inverse association with MCHC among males, but not among non-smoking females. Among men, those who smoked had stronger associations between arsenic exposures and MCHC than non-smoking males. Collectively, our results show that arsenic exposures affect multiple RBC parameters and highlight potentially important sex differences in arsenic-induced hematotoxicity.

Oxaliplatin-induced peripheral neurotoxicity in colorectal cancer patients: mechanisms, pharmacokinetics and strategies

Oxaliplatin-based chemotherapy is a standard treatment approach for colorectal cancer (CRC). However, oxaliplatin-induced peripheral neurotoxicity (OIPN) is a severe dose-limiting clinical problem that might lead to treatment interruption. This neuropathy may be reversible after treatment discontinuation. Its complicated mechanisms are related to DNA damage, dysfunction of voltage-gated ion channels, neuroinflammation, transporters, oxidative stress, and mitochondrial dysfunction, etc. Several strategies have been proposed to diminish OIPN without compromising the efficacy of adjuvant therapy, namely, combination with chemoprotectants (such as glutathione, Ca/Mg, ibudilast, duloxetine, etc.), chronomodulated infusion, dose reduction, reintroduction of oxaliplatin and topical administration [hepatic arterial infusion chemotherapy (HAIC), pressurized intraperitoneal aerosol chemotherapy (PIPAC), and hyperthermic intraperitoneal chemotherapy (HIPEC)]. This article provides recent updates related to the potential mechanisms, therapeutic strategies in treatment of OIPN, and pharmacokinetics of several methods of oxaliplatin administration in clinical trials.

Serum levels of erythropoietin in patients with chronic obstructive pulmonary disease and anemia

The important association of erythropoietin (EPO) serum levels and chronic obstructive pulmonary disease (COPD) with anemia has been inadequately studied and remains a controversial issue. We aimed to shed light on this matter by comparing EPO levels in anemic and non-anemic COPD patients, along with a review of published literature. This cross-sectional study was conducted on COPD patients referred to the pulmonary clinic of Shahid Faghihi Hospital and Motahari clinic, Shiraz, Iran, for one year. We measured complete blood count, red blood cell indices, serum iron, TIBC and ferritin levels, serum EPO levels, and body mass index. Among 35 patients in this study, 28 males and 7 females were enrolled with a mean age of 54.57 ± 8.07 years. The average Forced expiratory volume in first second (FEV1) was 37.26 ± 7.33% and FEV1/FVC was 0.46 ± 0.12. Mean EPO levels were 30.29 ± 2.066 mU/mL. No statistically significant association was observed among erythropoietin levels and Hb, COPD severity, and age. There was no significant difference in EPO levels between anemic and non-anemic patients. EPO level, against the traditional expectation, didn't increase in COPD patients. EPO production also didn't compensate for the anemia of chronic disease which considers as a common comorbid disorder in these patients.

Multicompartmental trauma alters bone marrow erythroblastic islands

BACKGROUND

Trauma is associated with widespread inflammation, neuroendocrine activation, and an inadequate bone marrow response to anemia. During late-stage erythropoiesis, erythroid progenitors/erythroblasts form clusters on the surface of specialized bone marrow macrophages where they are supported through terminal differentiation and enucleation. We hypothesized that these erythroblastic islands (EBIs) are adversely impacted by severe trauma.

METHODS

Male Sprague-Dawley rats (n = 8/group) were subjected to either multiple injuries (PT) (lung contusion, hemorrhagic shock, cecectomy, and bifemoral pseudofractures), PT plus 2 hours of daily chronic restraint stress (PT/CS), or naive controls. Bone marrow was harvested on days 2 and 7. Nuclear-stained, enriched bone marrow EBIs were fixed and stained for CD71, VCAM-1, and CD163, and confocal images were obtained at 20 times magnification. Numbers of erythroid cells/EBI and ratio of reticulocytes/EBI were counted by a blinded observer. Differences were compared using analysis of variance, with significance defined as p < 0.05.

RESULTS

PT and PT/CS had significantly reduced numbers of erythroid cells per EBI on day 2 when compared with naive (PT: 5.9 ± 1.0 cells [ p < 0.05], PT/CS: 6.8 ± 0.8 cells [ p < 0.05] vs. naive: 8.5 ± 0.8 cells). On day 7, the number of erythroid cells/EBI increased following PT (8.3 ± 0.4 cells) but remained reduced following PT/CS (5.9 ± 0.5 cells [ p < 0.05]). This correlated with an increased proportion of reticulocytes/EBI on day 7 following PT, which was not present following PT/CS (PT: 54% [ p < 0.05] vs. PT/CS: 28%).

CONCLUSION

Late-stage erythropoiesis was altered following multicompartmental PT early after injury, and these alterations persisted with the addition of daily chronic stress. Alterations in EBI structure and function after severe trauma and critical illness may serve as a promising new area of study to improve mechanistic understanding of persistent anemia after trauma.

HbA1c as a time predictive biomarker for an additional islet autoantibody and type 1 diabetes in seroconverted TEDDY children

OBJECTIVE

Increased level of glycated hemoglobin (HbA1c) is associated with type 1 diabetes onset that in turn is preceded by one to several autoantibodies against the pancreatic islet beta cell autoantigens; insulin (IA), glutamic acid decarboxylase (GAD), islet antigen-2 (IA-2) and zinc transporter 8 (ZnT8). The risk for type 1 diabetes diagnosis increases by autoantibody number. Biomarkers predicting the development of a second or a subsequent autoantibody and type 1 diabetes are needed to predict disease stages and improve secondary prevention trials. This study aimed to investigate whether HbA1c possibly predicts the progression from first to a subsequent autoantibody or type 1 diabetes in healthy children participating in the Environmental Determinants of Diabetes in the Young (TEDDY) study.

RESEARCH DESIGN AND METHODS

A joint model was designed to assess the association of longitudinal HbA1c levels with the development of first (insulin or GAD autoantibodies) to a second, second to third, third to fourth autoantibody or type 1 diabetes in healthy children prospectively followed from birth until 15 years of age.

RESULTS

It was found that increased levels of HbA1c were associated with a higher risk of type 1 diabetes (HR 1.82, 95% CI [1.57-2.10], p < 0.001) regardless of first appearing autoantibody, autoantibody number or type. A decrease in HbA1c levels was associated with the development of IA-2A as a second autoantibody following GADA (HR 0.85, 95% CI [0.75, 0.97], p = 0.017) and a fourth autoantibody following GADA, IAA and ZnT8A (HR 0.90, 95% CI [0.82, 0.99], p = 0.036). HbA1c trajectory analyses showed a significant increase of HbA1c over time (p < 0.001) and that the increase is more rapid as the number of autoantibodies increased from one to three (p < 0.001).

CONCLUSION

In conclusion, increased HbA1c is a reliable time predictive marker for type 1 diabetes onset. The increased rate of increase of HbA1c from first to third autoantibody and the decrease in HbA1c predicting the development of IA-2A are novel findings proving the link between HbA1c and the appearance of autoantibodies.

Black Cohosh Herbal Extract and Hematologic Alterations in B6C3F1/N Mice

Black cohosh is a readily available dietary supplement currently marketed as a remedy for dysmenorrhea and menopausal symptoms and is one of the top-selling herbal supplements in the United States. Black cohosh extract (BCE) was nominated to the National Toxicology Program (NTP) by the National Cancer Institute and the National Institute of Environmental Health Sciences due to its widespread use and lack of animal toxicity studies. Results of the NTP BCE subchronic mouse toxicity study revealed a dose-dependent, non-regenerative decrease in the erythron with an increase in the mean corpuscular volume (macrocytosis). Howell-Jolly bodies, or micronuclei, were significantly increased. These particular changes indicated an ineffective erythropoiesis consistent with a condition known as megaloblastic anemia. Megaloblastic anemia is due to disruptions in DNA synthesis during hematopoiesis and can be a result of an inherited or drug-induced disorder or a consequence of folate or cobalamin deficiency. Subsequent mouse studies revealed hematological and biochemical changes that were consistent with a functional cobalamin deficiency. This article will review basic mechanisms and laboratory features of megaloblastic anemia. The results of our studies including morphological abnormalities of the erythron and biomarkers of folate and cobalamin deficiencies, as well as hepatic microarray gene changes, are also discussed.

Arsenic impairs the lineage commitment of hematopoietic progenitor cells through the attenuation of GATA-2 DNA binding activity

Arsenic exposure produces significant hematotoxicity in vitro and in vivo. Our previous work shows that arsenic (in the form of arsenite, AsIII) interacts with the zinc finger domains of GATA-1, inhibiting the function of this critical transcription factor, and resulting in the suppression of erythropoiesis. In addition to GATA-1, GATA-2 also plays a key role in the regulation of hematopoiesis. GATA-1 and GATA-2 have similar zinc finger domains (C4-type) that are structurally favorable for AsIII interactions. Taking this into consideration, we hypothesized that early stages of hematopoietic differentiation that are dependent on the function of GATA-2 may also be disrupted by AsIII exposure. We found that in vitro AsIII exposures disrupt the erythromegakaryocytic lineage commitment and differentiation of erythropoietin-stimulated primary mouse bone marrow hematopoietic progenitor cells (HPCs), producing an aberrant accumulation of cells in early stages of hematopoiesis and subsequent reduction of committed erythro-megakaryocyte progenitor cells. Arsenic significantly accumulated in the GATA-2 protein, causing the loss of zinc, and disruption of GATA-2 function, as measured by chromatin immunoprecipitation and the expression of GATA-2 responsive genes. Our results show that the attenuation of GATA-2 function is an important mechanism contributing to the aberrant lineage commitment and differentiation of early HPCs. Collectively, findings from the present study suggest that the AsIII-induced disruption of erythro-megakaryopoiesis may contribute to the onset and/or exacerbation of hematological disorders, such as anemia.

Significantly lower mean serum vitamin B12 and folic acid levels and a significantly higher frequency of serum iron deficiency in younger than in older atrophic glossitis patients

Background/purpose

: Our previous study found that 19.0%, 16.9%, 5.3%, 2.3%, and 11.9% of 1064 atrophic glossitis (AG) patients have anemia, serum iron, vitamin B12, and folic acid deficiencies, and hyperhomocysteinemia, respectively. This study mainly evaluated the anemia, hematinic deficiencies, and hyperhomocysteinemia in 224 younger (≤50 years old) and 840 older (>50 years old) AG patients.

Materials and methods

The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, and homocysteine levels in 224 younger and 840 older AG patients were measured and compared with the corresponding levels in 112 younger (≤50 years old) and 420 older (>50 years old) healthy control subjects (HCSs), respectively.

Results

We found that 224 younger AG patients had significantly lower mean blood Hb and serum iron levels than 112 younger HCSs. Moreover, 840 older AG patients had significantly lower mean blood Hb and serum iron levels and a significantly higher mean serum homocysteine level than 420 older HCSs. In addition, 224 younger AG patients had significantly lower mean serum vitamin B12 and folic acid levels, a lower mean serum homocysteine level (marginal significance, P = 0.056), a significantly higher frequency of serum iron deficiency, and a significantly lower frequency of hyperhomocysteinemia than 840 older AG patients.

Conclusion

The younger AG patients do have significantly lower mean serum vitamin B12 and folic acid levels, a significantly higher frequency of serum iron deficiency, and a significantly lower frequency of hyperhomocysteinemia than the older AG patients.

Significantly higher frequencies of macrocytosis, anemia, serum vitamin B12 and folic acid deficiencies, and hyperhomocysteinemia in male than in female atrophic glossitis patients

Background/purpose

Our previous study found that 19.0%, 16.9%, 5.3%, 2.3%, 11.9%, and 26.7% of 1064 atrophic glossitis (AG) patients have anemia, serum iron, vitamin B12, and folic acid deficiencies, hyperhomocysteinemia, and serum gastric parietal cell antibody (GPCA) positivity, respectively. This study evaluated the anemia, hematinic deficiencies, and hyperhomocysteinemia in 150 male and 914 female AG patients.

Materials and methods

The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, homocysteine, GPCA levels in 150 male and 914 female AG patients were measured and compared with the corresponding levels in 75 male and 457 female healthy control subjects (HCSs), respectively.

Results

We found that 150 male AG patients had significantly lower mean blood Hb, serum iron, vitamin B12, and folic acid levels, and significantly higher mean serum homocysteine levels than 75 male HCSs. Moreover, 914 female AG patients had significantly lower mean blood Hb and serum iron levels and significantly higher mean serum homocysteine level than 457 female HCSs. In addition, 150 male AG patients had significantly higher mean blood Hb and serum homocysteine levels, significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of Hb, vitamin B12, and folic acid deficiency and hyperhomocysteinemia than 914 female AG patients.

Conclusion

The male AG patients do have significantly higher mean blood Hb and serum homocysteine levels, significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of Hb, vitamin B12, and folic acid deficiencies and hyperhomocysteinemia than the female AG patients.

Steamed Panax notoginseng attenuates renal anemia in an adenine-induced mouse model of chronic kidney disease

ETHNOPHARMACOLOGICAL RELEVANCE

Panax notoginseng (PN) (Burk.) F. H. Chen is a medicinal herb used to treat blood disorders since ancient times, of which the steamed form exhibits the anti-anemia effect and acts with a "blood-tonifying" function according to the traditional use. However, its pharmacological effect and mechanism on alleviating renal anemia (RA) are still unclear.

AIMS OF THE STUDY

The study aims to investigate the effect of steamed Panax notoginseng (SPN) to attenuate RA and its underlying mechanism based on the model of adenine-induced RA mice.

MATERIALS AND METHODS

Seventy mice were randomly divided into seven groups of ten: the control group, model group, the erythropoietin (EPO) group, the Fufang E'jiao Jiang (FEJ) group, the high-dose steamed PN (H-SPN) group, the middle-dose steamed PN (M-SPN) group, and the low-dose steamed PN (L-SPN) group. The adenine induction RA model was applied to assess the "blood enriching" function of SPN. The blood routine indexes, erythrocyte fragility, pathologic morphology of kidney tissue and the expression levels of related cytokines and proteins in the mice were detected after 3-week administration with SPN and positive drugs.

RESULTS

Our study provided evidences that SPN could ameliorate RA. Compared with the control group, SPN could attenuate RA by significantly increasing the numbers of peripheral blood cells (p < 0.01), improving the erythrocyte fragility (p < 0.01), and restoring the expression of EPO mRNA in the kidneys and EPO receptor mRNA in bone marrow nucleated cells. The expression of TGF-β₁ mRNA was declined and the expression of HGF mRNA was significantly increased in a dose-dependent way after the treatment of SPN. Additionally, the expression of Bcl-2 and Bcl-2/Bax ratio in the kidneys were significantly increased. In contrast, there was a highly significant decrease in the expression of Bax (p < 0.01), following SPN treatment.

CONCLUSION

SPN could alleviate RA by promoting the overall hematopoiesis and inhibiting the progress of renal injury in mice.

Anemia, hematinic deficiencies, and hyperhomocysteinemia in younger and older burning mouth syndrome patients

Abstract Background/purpose

Our previous study found that 19.8%, 16.2%, 4.8%, 2.3%, and 19.2% of 884 burning mouth syndrome (BMS) patients have anemia, serum iron, vitamin B12, and folic acid deficiencies, and hyperhomocysteinemia, respectively. This study mainly evaluated the anemia, hematinic deficiencies, and hyperhomocysteinemia in 272 younger (≤50 years old) and 612 older (>50 years old) BMS patients.

Materials and methods

The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, and homocysteine levels in 272 younger and 612 older BMS patients were measured and compared with the corresponding levels in 136 younger (≤50 years old) and 306 older (>50 years old) healthy control subjects (HCSs), respectively.

Results

We found that 272 younger BMS patients had significantly lower mean blood Hb and serum iron, vitamin B12, and folic acid levels than 136 younger HCSs. Moreover, 612 older BMS patients had significantly lower mean blood Hb, and serum iron and vitamin B12 levels and significantly higher mean serum homocysteine level than 306 older HCSs. In addition, 272 younger BMS patients had higher mean blood Hb level (marginal significance, P = 0.056), significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of iron and folic acid deficiencies than 612 older BMS patients.

Conclusion

The younger BMS patients do have higher mean blood Hb level, significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of serum iron and folic acid deficiencies than the older BMS patients.

Anemia, hematinic deficiencies, hyperhomocysteinemia, and gastric parietal cell antibody positivity in burning mouth syndrome patients with normocytosis

Background/Purpose

Normocytosis is defined as having the mean corpuscular volume (MCV) between 80 fL and 99.9 fL. This study evaluated whether 770 burning mouth syndrome (BMS) patients with normocytosis (so-called normocytosis/BMS patients) had significantly higher frequencies of anemia, hematinic deficiencies, hyperhomocysteinemia, and serum gastric parietal cell antibody (GPCA) positivity than 442 healthy control subjects or 884 BMS patients.

Materials and methods

Complete blood count, serum iron, vitamin B12, folic acid, homocysteine, and GPCA levels in 884 BMS patients (including 770 normocytosis/BMS patients) and 442 healthy control subjects were measured and compared.

Results

We found that 12.3%, 13.2%, 2.2%, 2.3%, 17.3%, and 10.5% of 770 normocytosis/BMS patients had blood hemoglobin (Hb), iron, vitamin B12, and folic acid deficiencies, hyperhomocysteinemia, and serum GPCA positivity, respectively. Furthermore, 770 normocytosis/BMS patients had significantly higher frequencies of blood Hb, iron, vitamin B12, and folic acid deficiencies, hyperhomocysteinemia, and serum GPCA positivity than 442 healthy control subjects (all P-values < 0.005). On the contrary, 770 normocytosis/BMS patients had significantly lower frequencies of blood Hb and vitamin B12 deficiencies than overall 884 BMS patients (both P-values < 0.01).

Conclusion

We conclude that there are significantly higher frequencies of anemia, serum iron, vitamin B12, and folic acid deficiencies, hyperhomocysteinemia, and serum GPCA positivity in normocytosis/BMS patients than in healthy control subjects. On the contrary, normocytosis/BMS patients do have significantly lower frequencies of blood Hb and vitamin B12 deficiencies than overall BMS patients.

Transcriptional Control of Gene Expression and the Heterogeneous Cellular Identity of Erythroblastic Island Macrophages

During definitive erythropoiesis, maturation of erythroid progenitors into enucleated reticulocytes requires the erythroblastic island (EBI) niche comprising a central macrophage attached to differentiating erythroid progenitors. Normally, the macrophage provides a nurturing environment for maturation of erythroid cells. Its critical physiologic importance entails aiding in recovery from anemic insults, such as systemic stress or acquired disease. Considerable interest in characterizing the central macrophage of the island niche led to the identification of putative cell surface markers enriched in island macrophages, enabling isolation and characterization. Recent studies focus on bulk and single cell transcriptomics of the island macrophage during adult steady-state erythropoiesis and embryonic erythropoiesis. They reveal that the island macrophage is a distinct cell type but with widespread cellular heterogeneity, likely suggesting distinct developmental origins and biological function. These studies have also uncovered transcriptional programs that drive gene expression in the island macrophage. Strikingly, the master erythroid regulator EKLF/Klf1 seems to also play a major role in specifying gene expression in island macrophages, including a putative EKLF/Klf1-dependent transcription circuit. Our present review and analysis of mouse single cell genetic patterns suggest novel expression characteristics that will enable a clear enrichment of EBI subtypes and resolution of island macrophage heterogeneity. Specifically, the discovery of markers such as Epor, and specific features for EKLF/Klf1-expressing island macrophages such as Sptb and Add2, or for SpiC-expressing island macrophage such as Timd4, or for Maf/Nr1h3-expressing island macrophage such as Vcam1, opens exciting possibilities for further characterization of these unique macrophage cell types in the context of their critical developmental function.

Anemia, hematinic deficiencies, and hyperhomocysteinemia in male and female burning mouth syndrome patients

Background/purpose

Our previous study found that 19.8%, 16.2%, 4.8%, 2.3%, 19.2%, and 12.3% of 884 burning mouth syndrome (BMS) patients have anemia, serum iron, vitamin B12, and folic acid deficiencies, hyperhomocysteinemia, and serum gastric parietal cell antibody (GPCA) positivity, respectively. This study mainly evaluated the anemia, hematinic deficiencies, and hyperhomocysteinemia in 212 male and 672 female BMS patients.

Materials and methods

The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, homocysteine, GPCA levels in 212 male and 672 female BMS patients were measured and compared with the corresponding levels in 106 male and 336 female healthy control subjects, respectively.

Results

We found that 212 male BMS patients had significantly lower mean blood Hb, serum iron, vitamin B12, and folic acid levels and significantly higher mean serum homocysteine levels than 106 male healthy control subjects. Moreover, 672 female BMS patients had significantly lower mean blood Hb and serum iron levels and significantly higher mean serum homocysteine level than 336 female healthy control subjects. In addition, 212 male BMS patients had significantly higher mean blood Hb and serum homocysteine levels, significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of folic acid deficiency and hyperhomocysteinemis than 672 female BMS patients.

Conclusion

The male BMS patients do have significantly higher mean blood Hb and serum homocysteine levels, significantly lower mean serum vitamin B12 and folic acid levels, and significantly higher frequencies of folic acid deficiency and hyperhomocysteinemis than the female BMS patients.

Arsenite exposure inhibits the erythroid differentiation of human hematopoietic progenitor CD34+ cells and causes decreased levels of hemoglobin

Arsenic exposure poses numerous threats to human health. Our previous work in mice has shown that arsenic causes anemia by inhibiting erythropoiesis. However, the impacts of arsenic exposure on human erythropoiesis remain largely unclear. We report here that low-dose arsenic exposure inhibits the erythroid differentiation of human hematopoietic progenitor cells (HPCs). The impacts of arsenic (in the form of arsenite; As3+) on red blood cell (RBC) development was evaluated using a long-term culture of normal human bone marrow CD34+-HPCs stimulated in vitro to undergo erythropoiesis. Over the time course studied, we analyzed the expression of the cell surface antigens CD34, CD71 and CD235a, which are markers commonly used to monitor the progression of HPCs through the stages of erythropoiesis. Simultaneously, we measured hemoglobin content, which is an important criterion used clinically for diagnosing anemia. As compared to control, low-dose As3+ exposure (100 nM and 500 nM) inhibited the expansion of CD34+-HPCs over the time course investigated; decreased the number of committed erythroid progenitors (BFU-E and CFU-E) and erythroblast differentiation in the subsequent stages; and caused a reduction of hemoglobin content. These findings demonstrate that low-dose arsenic exposure impairs human erythropoiesis, likely by combined effects on various stages of RBC formation.

Arsenite and monomethylarsonous acid disrupt erythropoiesis through combined effects on differentiation and survival pathways in early erythroid progenitors

Strong epidemiological evidence demonstrates an association between chronic arsenic exposure and anemia. We recently found that As+3 impairs erythropoiesis by disrupting the function of GATA-1; however the downstream pathways impacted by the loss of GATA-1 function have not been evaluated. Additionally, our previous findings indicate that the predominant arsenical in the bone marrow of mice exposed to As+3 in their drinking water for 30 days was MMA+3, but the impacts of this arsenical on erythorpoisis also remain largely unknown. The goal of this study was to address these critical knowledge gaps by evaluating the comparative effects of arsenite (As+3) and the As+3 metabolite, monomethyarsonous acid (MMA+3) on two critical regulatory pathways that control the differentiation and survival of early erythroid progenitor cells. We found that 500 nM As+3 and 100 and 500 nM MMA+3 suppress erythropoiesis by impairing the differentiation of early stage erythroid progenitors. The suppression of early erythroid progenitor cell development was attributed to combined effects on differentiation and survival pathways mediated by disruption of GATA-1 and STAT5. Our results show that As+3 primarily disrupted GATA-1 function; whereas, MMA+3 suppressed both GATA-1 and STAT5 activity. Collectively, these findings provide novel mechanistic insights into arsenic-induced dyserythropoiesis and suggest that MMA+3 may be more toxic than As+3 to early developing erythroid cells.

Oral iron supplementation in patients with chronic kidney disease: Can it be harmful to the gut microbiota?

Patients with chronic kidney disease (CKD) have several pathophysiological alterations, including anemia, one of the first changes in CKD patients. More recently, researchers have observed that the intestinal microbiota alterations are also another complication in these patients. The most common treatment for anemia is oral (mainly ferrous sulfate) or intravenous iron supplementation. Despite being a necessary treatment, recent studies have reported that supplementation with oral iron may increase its availability in the intestine, leading to disturbance in the gut microbiota and also to oxidative stress in the enterocytes, which may change the permeability and the microbiota profile. Although it is a therapy routinely used in patients with CKD, supplementation with oral iron on the gut microbiota has been rarely studied in these patients. Thus, this review will discuss the relationship between iron and the gut microbiota and the possible effects of oral iron supplementation on gut microbiota in patients with CKD.

Receptor-mediated mitophagy regulates EPO production and protects against renal anemia

Erythropoietin (EPO) drives erythropoiesis and is secreted mainly by the kidney upon hypoxic or anemic stress. The paucity of EPO production in renal EPO-producing cells (REPs) causes renal anemia, one of the most common complications of chronic nephropathies. Although mitochondrial dysfunction is commonly observed in several renal and hematopoietic disorders, the mechanism by which mitochondrial quality control impacts renal anemia remains elusive. In this study, we showed that FUNDC1, a mitophagy receptor, plays a critical role in EPO-driven erythropoiesis induced by stresses. Mechanistically, EPO production is impaired in REPs in Fundc1^-/- mice upon stresses, and the impairment is caused by the accumulation of damaged mitochondria, which consequently leads to the elevation of the reactive oxygen species (ROS) level and triggers inflammatory responses by up-regulating proinflammatory cytokines. These inflammatory factors promote the myofibroblastic transformation of REPs, resulting in the reduction of EPO production. We therefore provide a link between aberrant mitophagy and deficient EPO generation in renal anemia. Our results also suggest that the mitochondrial quality control safeguards REPs under stresses, which may serve as a potential therapeutic strategy for the treatment of renal anemia.

Anemia, hematinic deficiencies, hyperhomocysteinemia, and gastric parietal cell antibody positivity in burning mouth syndrome patients with or without microcytosis

Background/purpose

Microcytosis is defined as having mean corpuscular volume <80 fL. This study evaluated whether 68 burning mouth syndrome (BMS) patients with microcytosis and 816 BMS patients without microcytosis had higher frequencies of anemia, hematinic deficiencies, hyperhomocysteinemia, and serum gastric parietal cell antibody (GPCA) positivity than 442 healthy control subjects.

Materials and methods

Complete blood count and serum iron, vitamin B12, folic acid, homocysteine, and GPCA levels in 68 BMS patients with microcytosis, 816 BMS patients without microcytosis, and 442 healthy control subjects were measured and compared.

Results

We found that 73.5%, 44.1%, 4.4%, 2.9%, 13.2%, and 10.3% of 68 BMS patients with microcytosis and 15.3%, 13.8%, 4.8%, 2.2%, 19.7%, and 12.5% of 816 BMS patients without microcytosis had blood hemoglobin, iron, vitamin B12, and folic acid deficiencies, hyperhomocysteinemia, and serum GPCA positivity, respectively. Both 68 BMS patients with microcytosis and 816 BMS patients without microcytosis had significantly higher frequencies of blood hemoglobin, iron, vitamin B12, and folic acid deficiencies, hyperhomocysteinemia, and serum GPCA positivity than 442 healthy control subjects (all P-values < 0.05). Moreover, 68 BMS patients with microcytosis had significantly higher frequencies of blood hemoglobin and iron deficiencies than 816 BMS patients without microcytosis.

Conclusion

There are significantly higher frequencies of anemia, serum iron, vitamin B12, and folic acid deficiencies, hyperhomocysteinemia, and serum GPCA positivity in BMS patients with or without microcytosis than in healthy control subjects. BMS patients with microcytosis have significantly higher frequencies of blood hemoglobin and iron deficiencies than BMS patients without microcytosis.

Beyond pigmentation: signs of liver protection during afamelanotide treatment in Swiss patients with erythropoietic protoporphyria, an observational study

Erythropoietic protoporphyria (EPP) is an ultra-rare inherited disorder with overproduction of protoporphyrin in maturating erythroblasts. This excess protoporphyrin leads to incapacitating phototoxic burns in sunlight exposed skin. Its biliary elimination causes cholestatic liver injury in 20% and terminal liver failure in 4% of EPP patients. Thereby, the risk of liver injury increases with increasing erythrocyte protoporphyrin concentrations. Afamelanotide, an α-melanocyte-stimulating hormone (MSH) analog inducing skin pigmentation, was shown to improve sunlight tolerance in EPP. Beyond this well-known effect on pigmentation, the MSHs have liver-protective effects and improve survival of maturating erythroblasts, effects described in animal or in vitro models to date only. We investigated whether afamelanotide treatment in EPP has effects on erythropoiesis, protoporphyrin concentrations, and liver injury by analyzing retrospectively our long-term safety data.

Methods

From the 47 Swiss EPP-patients treated at our center since 2006, we included those 38 patients in the current analysis who received at least one afamelanotide dose between 2016 and 2018 and underwent regular laboratory testing before and during the treatment. We compared the means of pretreatment measurements with those during the treatment.

Results

Protoporphyrin concentrations dropped from 21.39 ± 11.12 (mean ± SD) before afamelanotide to 16.83 ± 8.24 µmol/L (p < .0001) during treatment. Aspartate aminotransferase decreased from 26.67 ± 13.16 to 22.9 ± 7.76 IU/L (p = .0146). For both entities, patients with higher values showed a more progressive decrease, indicating a risk reduction of EPP-related liver disease. The pre-existing hypochromia and broad mean red-cell distribution width were further augmented under afamelanotide. This was more likely due to an influence of afamelanotide on maturating erythroblasts than due to an exacerbated iron deficiency, as mean zinc-protoporphyrin decreased significantly and ferritin remained unchanged. No serious afamelanotide-related adverse events were observed for a total of 240 treatment years.

Conclusion

Our findings point to a protective effect of afamelanotide on erythroblast maturation and protoporphyrin-induced liver injury.

Plain Language summary

Afamelanotide, a skin tanning hormone, may protect patients with erythropoietic protoporphyria not only from skin burns, but also from liver injury associated with the disease. Patients with erythropoietic protoporphyria (EPP), an inherited metabolic disease, suffer from light-induced skin burns and liver injury elicited by the accumulated light sensitizer protoporphyrin. The excess protoporphyrin is produced in red cell precursors in the bone marrow, and it is eliminated from the body via the liver and bile. A high protoporphyrin excretion burden damages the liver cells, the risk for this increases with higher protoporphyrin concentrations. About 20% of EPP patients show some sign of liver injury and 4% develop life-threatening liver dysfunction.Afamelanotide, closely related to natural α-melanocyte stimulating hormone (MSH), induces skin tanning. This effect protects EPP patients from light-induced skin burns as shown in previous studies. We have treated Swiss EPP patients with afamelanotide since 2006, and we regularly perform safety tests of this treatment.Recent in vitro and animal studies demonstrated α-MSH effects other than skin tanning, including an improved synthesis of red blood cell precursors in the bone-marrow and protection of the liver from experimentally induced damage. Until now, it is unknown whether afamelanotide has similar effects in the human organism.To study this question, we analyzed retrospectively the safety laboratory data of 38 Swiss patients, who received at least one dose of afamelanotide from 2016 to 2019. We found that both, the average protoporphyrin concentrations and aspartate aminotransferase, a test for liver function, improved during afamelanotide treatment as compared to before.We concluded that afamelanotide applied to EPP patients to protect them from light-induced skin burns also may reduce their risk of liver injury.

The VP1u of Human Parvovirus B19: A Multifunctional Capsid Protein with Biotechnological Applications

The viral protein 1 unique region (VP1u) of human parvovirus B19 (B19V) is a multifunctional capsid protein with essential roles in virus tropism, uptake, and subcellular trafficking. These functions reside on hidden protein domains, which become accessible upon interaction with cell membrane receptors. A receptor-binding domain (RBD) in VP1u is responsible for the specific targeting and uptake of the virus exclusively into cells of the erythroid lineage in the bone marrow. A phospholipase A₂ domain promotes the endosomal escape of the incoming virus. The VP1u is also the immunodominant region of the capsid as it is the target of neutralizing antibodies. For all these reasons, the VP1u has raised great interest in antiviral research and vaccinology. Besides the essential functions in B19V infection, the remarkable erythroid specificity of the VP1u makes it a unique erythroid cell surface biomarker. Moreover, the demonstrated capacity of the VP1u to deliver diverse cargo specifically to cells around the proerythroblast differentiation stage, including erythroleukemic cells, offers novel therapeutic opportunities for erythroid-specific drug delivery. In this review, we focus on the multifunctional role of the VP1u in B19V infection and explore its potential in diagnostics and erythroid-specific therapeutics.

Common variants in signaling transcription-factor-binding sites drive phenotypic variability in red blood cell traits

Genome-wide association studies identify genomic variants associated with human traits and diseases. Most trait-associated variants are located within cell-type-specific enhancers, but the molecular mechanisms governing phenotypic variation are less well understood. Here, we show that many enhancer variants associated with red blood cell (RBC) traits map to enhancers that are co-bound by lineage-specific master transcription factors (MTFs) and signaling transcription factors (STFs) responsive to extracellular signals. The majority of enhancer variants reside on STF and not MTF motifs, perturbing DNA binding by various STFs (BMP/TGF-β-directed SMADs or WNT-induced TCFs) and affecting target gene expression. Analyses of engineered human blood cells and expression quantitative trait loci verify that disrupted STF binding leads to altered gene expression. Our results propose that the majority of the RBC-trait-associated variants that reside on transcription-factor-binding sequences fall in STF target sequences, suggesting that the phenotypic variation of RBC traits could stem from altered responsiveness to extracellular stimuli.

Inhibition of red blood cell development by arsenic-induced disruption of GATA-1

Anemia is a hematological disorder that adversely affects the health of millions of people worldwide. Although many variables influence the development and exacerbation of anemia, one major contributing factor is the impairment of erythropoiesis. Normal erythropoiesis is highly regulated by the zinc finger transcription factor GATA-1. Disruption of the zinc finger motifs in GATA-1, such as produced by germline mutations, compromises the function of this critical transcription factor and causes dyserythropoietic anemia. Herein, we utilize a combination of in vitro and in vivo studies to provide evidence that arsenic, a widespread environmental toxicant, inhibits erythropoiesis likely through replacing zinc within the zinc fingers of the critical transcription factor GATA-1. We found that arsenic interacts with the N- and C-terminal zinc finger motifs of GATA-1, causing zinc loss and inhibition of DNA and protein binding activities, leading to dyserythropoiesis and an imbalance of hematopoietic differentiation. For the first time, we show that exposures to a prevalent environmental contaminant compromises the function of a key regulatory factor in erythropoiesis, producing effects functionally similar to inherited GATA-1 mutations. These findings highlight a novel molecular mechanism by which arsenic exposure may cause anemia and provide critical insights into potential prevention and intervention for arsenic-related anemias.

Erythropoietin regulation of red blood cell production: from bench to bedside and back

More than 50 years of efforts to identify the major cytokine responsible for red blood cell (RBC) production (erythropoiesis) led to the identification of erythropoietin (EPO) in 1977 and its receptor (EPOR) in 1989, followed by three decades of rich scientific discovery. We now know that an elaborate oxygen-sensing mechanism regulates the production of EPO, which in turn promotes the maturation and survival of erythroid progenitors. Engagement of the EPOR by EPO activates three interconnected signaling pathways that drive RBC production via diverse downstream effectors and simultaneously trigger negative feedback loops to suppress signaling activity. Together, the finely tuned mechanisms that drive endogenous EPO production and facilitate its downstream activities have evolved to maintain RBC levels in a narrow physiological range and to respond rapidly to erythropoietic stresses such as hypoxia or blood loss. Examination of these pathways has elucidated the genetics of numerous inherited and acquired disorders associated with deficient or excessive RBC production and generated valuable drugs to treat anemia, including recombinant human EPO and more recently the prolyl hydroxylase inhibitors, which act partly by stimulating endogenous EPO synthesis. Ongoing structure-function studies of the EPOR and its essential partner, tyrosine kinase JAK2, suggest that it may be possible to generate new "designer" drugs that control selected subsets of cytokine receptor activities for therapeutic manipulation of hematopoiesis and treatment of blood cancers.

Anemia, hematinic deficiencies, and hyperhomocysteinemia in gastric parietal cell antibody-positive and -negative burning mouth syndrome patients

BACKGROUND/PURPOSE

Our previous study found the serum gastric parietal cell antibody (GPCA) positivity in 12.3% of burning mouth syndrome (BMS) patients. This study assessed whether GPCA-positive BMS (GPCA⁺BMS) patients had significantly higher frequencies of macrocytosis, anemia, hematinic deficiencies, and hyperhomocysteinemia than healthy control subjects or GPCA-negative BMS (GPCA^-BMS) patients.

METHODS

The mean corpuscular volume, blood hemoglobin (Hb), and serum iron, vitamin B12, folic acid, homocysteine, and GPCA levels were measured and compared between any two of three groups of 109 GPCA⁺BMS patients, 775 GPCA^-BMS patients, and 442 healthy control subjects.

RESULTS

We found that 109 GPCA⁺BMS patients had significantly higher frequencies of macrocytosis, blood Hb and serum iron and vitamin B12 deficiencies, and hyperhomocysteinemia than 442 healthy control subjects (all P-values < 0.001) and significantly higher frequencies of macrocytosis, blood Hb and serum vitamin B12 deficiencies, and hyperhomocysteinemia than 775 GPCA^-BMS patients (all P-values < 0.01). Moreover, 775 GPCA^-BMS patients had significantly higher frequencies of macrocytosis, blood Hb and serum iron, vitamin B12, and folic acid deficiencies, and hyperhomocysteinemia than 442 healthy control subjects (all P-values < 0.005). Pernicious anemia (45.5%) and normocytic anemia (24.2%) were the two most common types of anemia in 33 anemic GPCA⁺BMS patients. Moreover, normocytic anemia (61.3%), thalassemia trait-induced anemia (15.5%), and iron deficiency anemia (14.1%) were the three most common types of anemia in 142 anemic GPCA^-BMS patients.

CONCLUSION

GPCA⁺BMS patients have significantly higher frequencies of macrocytosis, blood Hb and serum vitamin B12 deficiencies, and hyperhomocysteinemia than healthy control subjects or GPCA^-BMS patients.

Anemia, hematinic deficiencies, and gastric parietal cell antibody positivity in burning mouth syndrome patients with or without hyperhomocysteinemia

Background/purpose

Our previous study found that 170 of 884 burning mouth syndrome (BMS) patients have hyperhomocysteinemia. This study assessed whether these 170 BMS patients with hyperhomocysteinemia had significantly higher frequencies of anemia, hematinic deficiencies, and serum gastric parietal cell antibody (GPCA) positivity than 714 BMS patients without hyperhomocysteinemia or 442 healthy control subjects.

Materials and methods

The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, homocysteine, and GPCA levels in 170 BMS patients with hyperhomocysteinemia, 714 BMS patients without hyperhomocysteinemia, and 442 healthy control subjects were measured and compared.

Results

We found that 170 BMS patients with hyperhomocysteinemia had significantly higher frequencies of macrocytosis, blood Hb and serum iron, vitamin B12, and folic acid deficiencies, and serum GPCA positivity than 442 healthy control subjects (all P-values < 0.001) or 714 BMS patients without hyperhomocysteinemia (all P-values < 0.05). Anemia was found in 77 of 170 BMS patients with hyperhomocysteinemia and in 98 of 714 BMS patients without hyperhomocysteinemia. Normocytic anemia (47 cases) and pernicious anemia (15 cases) were the two most common types of anemia in 170 BMS patients with hyperhomocysteinemia. Moreover, normocytic anemia (48 cases), iron deficiency anemia (21 cases), and thalassemia trait-induced anemia (21 cases) were the three most common types of anemia in 714 BMS patients without hyperhomocysteinemia.

Conclusion

BMS patients with hyperhomocysteinemia had significantly higher frequencies of macrocytosis, anemia, serum iron, vitamin B12, and folic acid deficiencies, and serum GPCA positivity than healthy control subjects or BMS patients without hyperhomocysteinemia.

Anemia, hematinic deficiencies, hyperhomocysteinemia, and gastric parietal cell antibody positivity in burning mouth syndrome patients with vitamin B12 deficiency

Background/purpose

Our previous study found that 42 of 884 burning mouth syndrome (BMS) patients have vitamin B12 deficiency. This study assessed whether the vitamin B12-deficient BMS (B12D/BMS) patients had significantly higher frequencies of anemia, hematinic deficiencies, hyperhomocysteinemia, and serum gastric parietal cell antibody (GPCA) positivity than healthy control subjects and evaluated whether all B12D/BMS patients had pernicious anemia (PA).

Materials and methods

The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, homocysteine, and GPCA levels in 42 B12D/BMS patients and 442 healthy control subjects were measured and compared.

Results

We found that 42 B12D/BMS patients had significantly lower mean blood Hb and serum iron and vitamin B12 levels as well as significantly higher mean corpuscular volume (MCV) and mean serum homocysteine level than healthy control subjects (all P-values < 0.05). Moreover, 42 B12D/BMS patients had significantly higher frequencies of macrocytosis (52.4%), blood Hb (61.9%) and serum iron (26.2%) and vitamin B12 (100.0%) deficiencies, hyperhomocysteinemia (83.3%), and serum GPCA positivity (42.9%) than 442 healthy control subjects (all P-values < 0.001). Moreover, of 26 anemic B12D/BMS patients, 15 (57.7%) had PA, 5 (19.2%) had macrocytic anemia other than PA, 4 (15.4%) had normocytic anemia, and 2 (7.7%) had thalassemia trait-induced anemia.

Conclusion

B12D/BMS patients have significantly higher frequencies of macrocytosis, blood Hb and serum iron and vitamin B12 deficiencies, hyperhomocysteinemia, and serum GPCA positivity than healthy control subjects. Although PA is the most common type of anemia in our B12D/BMS patients, only 15 (35.7%) of 42 B12D/BMS patients have PA.

Anemia, hematinic deficiencies, hyperhomocysteinemia, and gastric parietal cell antibody positivity in burning mouth syndrome patients with iron deficiency

Background/purpose

Our previous study found that 143 of 884 burning mouth syndrome (BMS) patients have iron deficiency (ID). This study assessed whether all BMS patients with ID (so-called ID/BMS patients) had iron deficiency anemia (IDA) and evaluated whether the ID/BMS patients had significantly higher frequencies of anemia, hematinic deficiencies, hyperhomocysteinemia, and serum gastric parietal cell antibody (GPCA) positivity than healthy control subjects.

Materials and methods

The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, homocysteine, and GPCA levels in 143 ID/BMS patients and 442 healthy control subjects were measured and compared.

Results

We found that 143 ID/BMS patients had significantly lower mean blood Hb and serum iron, vitamin B12, folic acid levels as well as significantly higher mean serum homocysteine level than healthy control subjects (all P-values < 0.01). Moreover, 143 ID/BMS patients had significantly higher frequencies of blood Hb (55.9%) and serum iron (100.0%), vitamin B12 (7.7%), and folic acid (2.1%) deficiencies, hyperhomocysteinemia (27.3%), and serum GPCA positivity (12.6%) than 442 healthy control subjects (all P-values < 0.001). Furthermore, of 80 anemic ID/BMS patients, 5 (6.3%) had pernicious anemia, 5 (6.3%) had macrocytic anemia other than pernicious anemia, 42 (52.5%) had normocytic anemia, 21 (26.3%) had IDA, and 7 (8.8%) had thalassemia trait-induced anemia.

Conclusion

ID/BMS patients had significantly higher frequencies of blood Hb and serum iron, vitamin B12, and folic acid deficiencies, hyperhomocysteinemia, and serum GPCA positivity than healthy control subjects. Normocytic anemia is the most common type of anemia in ID/BMS patients.

Kidney-secreted erythropoietin lowers lipidemia via activating JAK2-STAT5 signaling in adipose tissue

Background

Dyslipidemia is commonly observed in various kidney diseases, renal specific secreted erythropoietin (EPO) may participate in this process. However, how this process is regulated remains elusive.

Method

Dyslipidemia was evaluated in chronic kidney disease and ischemia kidney injury animal model. Primary cultured adipocytes were harvested to investigate the lipid metabolic effect of EPO. Lipidemia was evaluated in EPO treated animals. Blood samples from cardiac surgery-induced kidney injury patient were collected to assess correlationship between EPO and lipidemia.

Findings

We found a decrease in secreted EPO and hypertriglyceridemia in chronic kidney disease (CKD) mice. In contrast, in renal ischemia animal model, increased EPO triggered by hypoxia signaling activation, was accompanied by decreased triglyceride (TG) in serum. Mechanistically, circulating EPO modulated JAK2-STAT5 signaling, which in turn enhanced lipid catabolism in peripheral adipose tissue and contributed to dysregulated lipidemia. Delivering of recombinant EPO into both wild type and CKD mice suppressed TG in serum by accelerating lipid catabolism in adipose tissue. In a cohort of patients diagnosed with acute kidney injury after cardiopulmonary bypass surgery, the decreased TG and cholesterol negatively correlated with increased EPO in serum.

Interpretation

This study depicted a new mechanism by which renal secreted EPO controlled lipidemia in kidney diseases including chronic kidney disease. Circulating EPO stimulated lipid catabolism by targeting JAK2-STATA5 signaling in peripheral adipose tissue, providing new therapeutic target for dyslipidemia treatment.

Funding

This work was supported by grants from the National Natural Science Foundation of China (Nos. 81700640 and 81970608).

Anemia, hematinic deficiencies, hyperhomocysteinemia, and gastric parietal cell antibody positivity in atrophic glossitis patients with vitamin B12 deficiency

BACKGROUND/PURPOSE

Our previous study found that 56 of 1064 atrophic glossitis (AG) patients have vitamin B12 deficiency. This study assessed whether the AG patients with vitamin B12 deficiency (B12D/AG patients) had significantly higher frequencies of anemia, hematinic deficiencies, hyperhomocysteinemia, and serum gastric parietal cell antibody (GPCA) positivity than healthy control subjects.

METHODS

The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, homocysteine, and GPCA levels in 56 B12D/AG patients and 532 healthy control subjects were measured and compared.

RESULTS

We found that 56 B12D/AG patients had significantly lower mean blood Hb and serum iron levels as well as significantly higher mean corpuscular volume (MCV) and mean serum homocysteine level than healthy control subjects (all P-values < 0.05). Moreover, 56 B12D/AG patients had significantly higher frequencies of macrocytosis (53.6%), blood Hb (64.3%), iron (26.8%), and folic acid (3.6%) deficiencies, hyperhomocysteinemia (89.3%), and serum GPCA positivity (55.4%) than 532 healthy control subjects (all P-values < 0.005). In addition, of 36 anemic B12D/AG patients, 22 (61.1%) had pernicious anemia (PA), 6 (16.7%) had macrocytic anemia other than PA, 4 (11.1%) had normocytic anemia, 3 (8.3%) had iron deficiency anemia (IDA), and one (2.8%) had microcytic anemia other than IDA and thalassemia trait-induced anemia.

CONCLUSION

We conclude that B12D/AG patients have significantly higher frequencies of macrocytosis, blood Hb, iron, and folic acid deficiencies, hyperhomocysteinemia, and serum GPCA positivity than healthy control subjects. PA is the most common type of anemia in our B12D/AG patients.

Anemia, hematinic deficiencies, and gastric parietal cell antibody positivity in atrophic glossitis patients with or without hyperhomocysteinemia

BACKGROUND/PURPOSE

Our previous study found that 127 of 1064 atrophic glossitis (AG) patients have hyperhomocysteinemia. This study assessed whether the AG patients with hyperhomocysteinemia had significantly higher frequencies of anemia, hematinic deficiencies, and serum gastric parietal cell antibody (GPCA) positivity than AG patients without hyperhomocysteinemia or healthy control subjects.

METHODS

The blood hemoglobin (Hb) and serum iron, vitamin B12, folic acid, homocysteine, and GPCA levels in 127 AG patients with hyperhomocysteinemia, 937 AG patients without hyperhomocysteinemia, and 532 healthy control subjects were measured and compared.

RESULTS

We found that 127 AG patients with hyperhomocysteinemia had significantly higher frequencies of blood Hb and serum iron, vitamin B12, and folic acid deficiencies and serum GPCA positivity than 532 healthy control subjects (all P-values < 0.001) and significantly higher frequencies of blood Hb and serum vitamin B12 and folic acid deficiencies and serum GPCA positivity than 937 AG patients without hyperhomocysteinemia (all P-values < 0.001). Moreover, 127 AG patients with hyperhomocysteinemia had significantly higher frequencies of macrocytic anemia and significantly lower frequencies of normocytic anemia than 937 AG patients without hyperhomocysteinemia (both P-values < 0.001). Pernicious anemia (22 cases) was found only in AG patients with hyperhomocysteinemia but not in AG patients without hyperhomocysteinemia.

CONCLUSION

AG patients with hyperhomocysteinemia had significantly higher frequencies of anemia, serum iron, vitamin B12, and folic acid deficiencies, and serum GPCA positivity than healthy control subjects and significantly higher frequencies of anemia, serum vitamin B12 and folic acid deficiencies, and serum GPCA positivity than AG patients without hyperhomocysteinemia.

Colla corii asini might upregulate ZNF471 and THOC5 by KRAB domain-containing zinc-finger protein pathway and THO complex subunit 5 pathway to improve anemia of pregnant women with β-thalassemia

Pregnant patients with β-thalassemia are more likely to have progressive anemia which expose them to risk of adverse pregnancy outcomes, blood transfusion, and iron overload. Results from our previous study indicated that Colla corii asini (CCA, E'jiao), a natural ingredient of traditional Chinese medicine, could significantly increase hemoglobin level of pregnant women with β- thalassemia, but the underlying molecular mechanism was unclear. Thus, we applied high-throughput transcriptome sequencing to study the transcriptomic change before and after the CCA treatment. Twenty eligible pregnant women were recruited and randomized to either the CCA treatment group or the blank control group in a 3:1 ratio. Patients in the treatment group orally received daily 15 g CCA powder for 4 weeks. We analyzed the therapeutic effect indexes and the transcriptomic change in subjects' peripheral blood before and after treatment. We found that β CD 41-42(-TTCT)/β^A was the main genotype of the subjects. The regulatory impact of CCA treatment became more evident among the subjects of genotype β CD 41-42(-TTCT)/β^A. Gene ontogenesis analysis revealed that the top five molecular functions of differentially expressed genes were involved in membrane functionality and cellular structure. We further identified two consistent upregulated genes ZNF471 and THOC5 in the effective treatment group, which were engaged in Kruppel-associated box (KRAB) domain-containing zinc-finger protein pathway and THOC5 pathway, respectively. Based on our current findings, we hypothesize that the anti-anemia effect of CCA on pregnant women with β-thalassemia might be related to translation regulation of spectrin synthesis, membrane stability, and eventually prolonged the life span of erythrocytes.

Association between Insulin-Like Growth Factor-I Levels and the Disease Progression and Anemia in Visceral Leishmaniasis

We analyzed the association between insulin-like growth factor-I (IGF-I) and the pathogenesis of anemia during active visceral leishmaniasis (VL). Serum levels of IGF-I, IGF-binding protein 3 (IGFBP3), and cytokines were measured in samples from individuals with active VL and cured VL, asymptomatic Leishmania-infected, and noninfected individuals. Then, we extended our analysis to VL dogs to evaluate hematimetric parameters, bone marrow alterations, and cytokine and IGF-I expression. We identified a positive correlation between lower IGF-I and IGFBP3 levels in active VL patients and lower hemoglobin levels. In infected dogs, there was a positive correlation between lower IGF-I expression in the bone marrow and lower peripheral blood hematocrit and hemoglobin levels. There was no correlation between decreased IGF-I level/expression and any measured cytokine serum levels in either host. The data suggest that low IGF-I expression is associated with pathogenesis of anemia in active VL, primarily in severe cases, by mechanisms other than alterations in cytokine production.

Effect of renal function and dialysis modality on daprodustat and predominant metabolite exposure

Background

Current therapies for anemia of chronic kidney disease (CKD) include administration of supplemental iron (intravenous and/or oral), blood transfusions and replacement of erythropoietin through the administration of recombinant human erythropoietin (rhEPO) and rhEPO analogs, each with limitations. Daprodustat is an orally active, small molecule hypoxia-inducible factor-prolyl hydroxylase inhibitor that is currently in Phase 3 clinical studies. As it is well appreciated that the kidney represents a major route of elimination of many drugs, and daprodustat will be administered to patients with advanced CKD as well as patients with end-stage kidney disease, it is important to characterize the pharmacokinetic profile in these patient populations to safely dose this potential new medicine.

Methods

The primary objective of these studies, conducted under two separate protocols and with identical assessments and procedures, was to characterize the steady-state pharmacokinetics of daprodustat and the six predominant metabolites (i.e. metabolites present in the highest concentration in circulation) in subjects with normal renal function, anemic non-dialysis (ND)-dependent CKD subjects (CKD Stage 3/4) and anemic subjects on either hemodialysis (HD) or peritoneal dialysis (PD). All enrolled subjects were administered daprodustat 5 mg once daily for 14 days (all except HD subjects) or 15 days (for HD subjects). Blood, urine and peritoneal dialysate were collected at various times for measurement of daprodustat, predominant metabolite, erythropoietin and hepcidin levels.

Results

The pharmacokinetic properties of steady-state daprodustat peak plasma concentration (Cmax), area under the plasma daprodustat concentration-time curve (AUC) and the time of Cmax (tmax) were comparable between all cohorts in this study. In addition, there was no clinically relevant difference in these properties in the HD subjects between a dialysis and ND day. For CKD Stage 3/4, HD (dialysis day) and PD subjects, the AUC of all daprodustat metabolites assessed was higher, while the C_max was slightly higher than that in subjects with normal renal function. Over the course of the 14 or 15 days of daprodustat administration, hemoglobin levels were seen to be relatively stable in the subjects with normal renal function, CKD Stage 3/4 and PD subjects, while HD subjects had a decrease of 1.9 gm/dL. All renally impaired subjects appeared to have similar erythropoietin responses to daprodustat, with approximately a 3-fold increase in these levels. In subjects with minimal to no change in hemoglobin levels, hepcidin levels remained relatively stable. Daprodustat, administered 5 mg once daily for 14–15 days, was generally well tolerated with a safety profile consistent with this patient population.

Conclusion

These studies demonstrated no clinically meaningful change in the pharmacokinetic properties of daprodustat when administered to subjects with various degrees of renal impairment, while for CKD Stage 3/4, HD (dialysis day) and PD subjects, the C_max and AUC of all daprodustat metabolites assessed were higher than in subjects with normal renal function. Administration of daprodustat in this study appeared to be generally safe and well tolerated.

Emergency Medicine Evaluation and Management of Anemia

Anemia is a common condition and is diagnosed on laboratory assessment. It is defined by abnormally low hemoglobin concentration or decreased red blood cells. Several classification systems exist. Laboratory markers provide important information. Acute anemia presents with symptoms owing to acute blood loss; chronic anemia may present with worsening fatigue, dyspnea, lightheadedness, or chest pain. Specific treatments depend on the underlying anemia and etiology. Iron is an alternative treatment for patients with microcytic anemia owing to iron deficiency. Hyperbaric oxygen is an option for alternative rescue therapy. Most patients with chronic anemia may be discharged with follow-up if hemodynamically stable.

Integrating Enhancer Mechanisms to Establish a Hierarchical Blood Development Program

Hematopoietic development requires the transcription factor GATA-2, and GATA-2 mutations cause diverse pathologies, including leukemia. GATA-2-regulated enhancers increase Gata2 expression in hematopoietic stem/progenitor cells and control hematopoiesis. The +9.5-kb enhancer activates transcription in endothelium and hematopoietic stem cells (HSCs), and its deletion abrogates HSC generation. The -77-kb enhancer activates transcription in myeloid progenitors, and its deletion impairs differentiation. Since +9.5^-/- embryos are HSC deficient, it was unclear whether the +9.5 functions in progenitors or if GATA-2 expression in progenitors solely requires -77. We further dissected the mechanisms using -77;+9.5 compound heterozygous (CH) mice. The embryonic lethal CH mutation depleted megakaryocyte-erythrocyte progenitors (MEPs). While the +9.5 suffices for HSC generation, the -77 and +9.5 must reside on one allele to induce MEPs. The -77 generated burst-forming unit-erythroid through the induction of GATA-1 and other GATA-2 targets. The enhancer circuits controlled signaling pathways that orchestrate a GATA factor-dependent blood development program.

Physiology and pathophysiology of renal erythropoietin-producing cells

Anemia is a common complication and contributes to increased morbidity and mortality in chronic kidney disease (CKD) patients. Whereas there has been a significant improvement of understanding the underlying mechanism of erythropoiesis, the treatment of renal anemia is still restricted to erythropoietin (EPO)-stimulating agents. The purpose of this article is to review the physiology of erythropoiesis, functional role of EPO and underlying molecular and cellular basis that regulate EPO production. Regulation of EPO production is at mRNA level. When anemia or hypoxia occurs, transcriptional factor, hypoxia-inducible factor (HIF), binds to EPO 5' hypoxic response element and EPO gene transcription increases. The renal EPO is mainly produced by pericytes. In CKD, pericytes transdifferentiate to myofibroblasts, and subsequently the ability of EPO production decreases, leading to renal anemia. Recent experimental and clinical studies show the promising efficacy of prolyl hydroxylase inhibitors in renal anemia through increasing EPO production by stabilizing HIF. Recent advances on epigenetics create a new field to study EPO gene expression at chromatin level. We will discuss the role of demethylating agent on restoring EPO expression, providing a novel approach to the treatment of renal anemia.

Molecular responses to therapeutic proteasome inhibitors in multiple myeloma patients are donor-, cell type- and drug-dependent

Proteasome is central to proteostasis network functionality and its over-activation represents a hallmark of advanced tumors; thus, its selective inhibition provides a strategy for the development of novel antitumor therapies. In support, proteasome inhibitors, e.g. Bortezomib or Carfilzomib have demonstrated clinical efficacy against hematological cancers. Herein, we studied proteasome regulation in peripheral blood mononuclear cells and erythrocytes isolated from healthy donors or from Multiple Myeloma patients treated with Bortezomib or Carfilzomib. In healthy donors we found that peripheral blood mononuclear cells express higher, as compared to erythrocytes, basal proteasome activities, as well as that proteasome activities decline during aging. Studies in cells isolated from Multiple Myeloma patients treated with proteasome inhibitors revealed that in most (but, interestingly enough, not all) patients, proteasome activities decline in both cell types during therapy. In peripheral blood mononuclear cells, most proteostatic genes expression patterns showed a positive correlation during therapy indicating that proteostasis network modules likely respond to proteasome inhibition as a functional unit. Finally, the expression levels of antioxidant, chaperone and aggresomes removal/autophagy genes were found to inversely associate with patients' survival. Our studies will support a more personalized therapeutic approach in hematological malignancies treated with proteasome inhibitors.

Tropomodulin 1 controls erythroblast enucleation via regulation of F-actin in the enucleosome

Biogenesis of mammalian red blood cells requires nuclear expulsion by orthochromatic erythoblasts late in terminal differentiation (enucleation), but the mechanism is largely unexplained. Here, we employed high-resolution confocal microscopy to analyze nuclear morphology and F-actin rearrangements during the initiation, progression, and completion of mouse and human erythroblast enucleation in vivo. Mouse erythroblast nuclei acquire a dumbbell-shaped morphology during enucleation, whereas human bone marrow erythroblast nuclei unexpectedly retain their spherical morphology. These morphological differences are linked to differential expression of Lamin isoforms, with primary mouse erythroblasts expressing only Lamin B and primary human erythroblasts only Lamin A/C. We did not consistently identify a continuous F-actin ring at the cell surface constriction in mouse erythroblasts, nor at the membrane protein-sorting boundary in human erythroblasts, which do not have a constriction, arguing against a contractile ring-based nuclear expulsion mechanism. However, both mouse and human erythroblasts contain an F-actin structure at the rear of the translocating nucleus, enriched in tropomodulin 1 (Tmod1) and nonmuscle myosin IIB. We investigated Tmod1 function in mouse and human erythroblasts both in vivo and in vitro and found that absence of Tmod1 leads to enucleation defects in mouse fetal liver erythroblasts, and in CD34⁺ hematopoietic stem and progenitor cells, with increased F-actin in the structure at the rear of the nucleus. This novel structure, the "enucleosome," may mediate common cytoskeletal mechanisms underlying erythroblast enucleation, notwithstanding the morphological heterogeneity of enucleation across species.

A Black Cohosh Extract Causes Hematologic and Biochemical Changes Consistent with a Functional Cobalamin Deficiency in Female B6C3F1/N Mice

Black cohosh rhizome, available as a dietary supplement, is most commonly marketed as a remedy for dysmenorrhea and menopausal symptoms. A previous subchronic toxicity study of black cohosh dried ethanolic extract (BCE) in female mice revealed a dose-dependent ineffective erythropoiesis with a macrocytosis consistent with the condition known as megaloblastic anemia. The purpose of this study was to investigate potential mechanisms by which BCE induces these particular hematological changes. B6C3F1/N female mice (32/group) were exposed by gavage to vehicle or 1,000 mg/kg BCE for 92 days. Blood samples were analyzed for hematology, renal and hepatic clinical chemistry, serum folate and cobalamin, red blood cell (RBC) folate, and plasma homocysteine and methylmalonic acid (MMA). Folate levels were measured in liver and kidney. Hematological changes included decreased RBC count; increased mean corpuscular volume; and decreased reticulocyte, white blood cell, neutrophil, and lymphocyte counts. Blood smear evaluation revealed increased Howell-Jolly bodies and occasional basophilic stippling in treated animals. Plasma homocysteine and MMA concentrations were increased in treated animals. Under the conditions of our study, BCE administration caused hematological and clinical chemistry changes consistent with a functional cobalamin, and possibly folate, deficiency. Further studies are needed to elucidate the mechanism by which BCE causes increases in homocysteine and MMA.

Eryptosis in health and disease: A paradigm shift towards understanding the (patho)physiological implications of programmed cell death of erythrocytes

During the course of their natural ageing and upon injury, anucleate erythrocytes can undergo an unconventional apoptosis-like cell death, termed eryptosis. Eryptotic erythrocytes display a plethora of morphological alterations including volume reduction, membrane blebbing and breakdown of the membrane phospholipid asymmetry resulting in phosphatidylserine externalization which, in turn, mediates their phagocytic recognition and clearance from the circulation. Overall, the eryptosis machinery is tightly orchestrated by a wide array of endogenous mediators, ion channels, membrane receptors, and a host of intracellular signaling proteins. Enhanced eryptosis shortens the lifespan of circulating erythrocytes and confers a procoagulant phenotype; this phenomenon has been tangibly implicated in the pathogenesis of anemia, deranged microcirculation, and increased prothrombotic risk associated with a multitude of clinical conditions. Herein, we reviewed the molecular mechanisms dictating eryptosis and erythrophagocytosis and critically analyzed the current evidence leading to the pathophysiological ramifications of eryptotic cell death in the context of human disease.