Investigation of iron deficiency anaemia

From the marrow to the blood: optimising the diagnosis of iron deficiency in the setting of inflammation

Iron deficiency (ID) is a common condition with readily available treatment but can be challenging to diagnose. Traditional biomarkers of ID are acute-phase reactants, which complicate diagnosis in patients with co-existent inflammation. This study aimed to establish optimal biomarker diagnostic thresholds for ID diagnosis using bone marrow (BM) iron stores as the gold standard and the C-reactive protein (CRP) as an inflammatory marker. A cross-sectional study was carried out in the haematology department of a tertiary academic hospital. Patients undergoing BM biopsies for any reason were recruited for inclusion. Retrospective case finding was used to enrich the data for cases with confirmed BM ID. Laboratory markers including red cell indices, reticulocyte haemoglobin and iron studies were evaluated to establish optimal cut-offs for ID diagnosis. A CRP of >5 mg/L was used as a marker of inflammation. The study included 139 patients. Forty-two had BM ID, with a median serum ferritin (SF) of 48.5 μg/L. Ninety-six of 134 (72%) had inflammation with a CRP >5 mg/L. An SF of <80 μg/L had optimal sensitivity (69%) and specificity (94%) for ID diagnosis in the whole group (odds ratio 23.5; 95% confidence interval 4.3-129). In patients without inflammation, an SF cut-off of 80 μg/L had high sensitivity (93%) and specificity (96%). An SF <200 μg/L indicated ID in those with inflammation (sensitivity 78%, specificity 74%). A transferrin saturation of <13% in those with inflammation increased the diagnostic specificity (92%). The reticulocyte haemoglobin was unhelpful in diagnosing ID in this setting. In this hospital population, SF was the best parameter to diagnose ID, even in the presence of inflammation. The CRP was useful to identify populations with inflammation in whom higher SF thresholds could be used together with the transferrin saturation to accurately diagnose ID.

Prolactin Drives Iron Release from Macrophages and Uptake in Mammary Cancer Cells through CD44

Iron is an essential element for human health. In humans, dysregulated iron homeostasis can result in a variety of disorders and the development of cancers. Enhanced uptake, redistribution, and retention of iron in cancer cells have been suggested as an "iron addiction" pattern in cancer cells. This increased iron in cancer cells positively correlates with rapid tumor growth and the epithelial-to-mesenchymal transition, which forms the basis for tumor metastasis. However, the source of iron and the mechanisms cancer cells adopt to actively acquire iron is not well understood. In the present study, we report, for the first time, that the peptide hormone, prolactin, exhibits a novel function in regulating iron distribution, on top of its well-known pro-lactating role. When stimulated by prolactin, breast cancer cells increase CD44, a surface receptor mediating the endocytosis of hyaluronate-bound iron, resulting in the accumulation of iron in cancer cells. In contrast, macrophages, when treated by prolactin, express more ferroportin, the only iron exporter in cells, giving rise to net iron output. Interestingly, when co-culturing macrophages with pre-stained labile iron pools and cancer cells without any iron staining, in an iron free condition, we demonstrate direct iron flow from macrophages to cancer cells. As macrophages are one of the major iron-storage cells and it is known that macrophages infiltrate tumors and facilitate their progression, our work therefore presents a novel regulatory role of prolactin to drive iron flow, which provides new information on fine-tuning immune responses in tumor microenvironment and could potentially benefit the development of novel therapeutics.

Prevalence of Micronutrient Deficiencies in Preoperative Bariatric Patients in a New Zealand Tertiary Centre

PURPOSE

A potential complication of bariatric surgery is development of nutritional deficiencies. Study aims were to assess prevalence of micronutrient deficiencies in preoperative bariatric patients and to examine for ethnic differences.

METHODS

Retrospective analysis of 573 patients that underwent bariatric surgery at Counties Manukau District Health Board was carried out. Mean preoperative levels of albumin, calcium, phosphate, folate, vitamin B12, vitamin D, magnesium, haemoglobin, haematocrit, mean cell volume, mean cell haemoglobin, ferritin, iron, and transferrin were calculated. Chi square, fisher exact test, and multiple logistic regression was used to assess for differences in prevalence of micronutrient deficiencies across ethnicities.

RESULTS

The most common micronutrient deficiency was vitamin D (30.85%). There were statistically significant differences in vitamin D deficiency across ethnicities (p < 0.0001). Asians had the highest prevalence of vitamin D deficiency (60%), followed by Pacifica (44.57%), and Māori (31.68%). Asians were more likely to have vitamin D deficiency compared to NZ/Other Europeans (OR = 14.93, p < 0.001). Vitamin D deficiency was associated with higher BMI (OR = 1.05, p = 0.008). The second most common deficiency was iron (21.1%). Asians had the highest prevalence of iron deficiency (44%), followed by Māori (27.95%), and Pacifica (19.57%) (p = 0.0064). Compared to NZ/Other Europeans, Asians (OR = 4.26) and Māori (OR = 1.78) were more likely to be iron deficient (p = 0.004). Female gender was associated with iron deficiency (OR = 2.12, p = 0.007).

CONCLUSION

Vitamin D and iron are the most common micronutrient deficiencies among preoperative bariatric patients in this cohort and ethnic differences were seen. There may be a role for preoperative supplementation in these at-risk ethnic groups.

A Prospective Observational Study Analyzing the Diagnostic Value of Hepcidin-25 for Anemia in Patients with Inflammatory Bowel Diseases

Iron deficiency (IDA) and chronic disease (ACD) anemia are complications of inflammatory bowel diseases (IBDs). Therapeutic modalities in remission and active IBD depend on the type of anemia. This study evaluated the link between hepcidin-25, proinflammatory cytokines, and platelet activation markers as biomarkers of anemia and inflammation in active IBD and remission. This prospective observational study included 62 patients with IBD (49 with ulcerative colitis and 13 with Crohn's) and anemia. Patients were divided into Group I (no or minimal endoscopic signs of disease activity and IDA), Group II (moderate and major endoscopic signs of disease activity and mild ACD), and Control group (10 patients with IBD in remission, without anemia). We assessed the difference among groups in the levels of CRP, hemoglobin (Hgb), serum iron, ferritin, hepcidin-25, interleukins, TNF-α, IFN-γ, soluble CD40 ligand, and sP-selectin. Hepcidin-25 levels were significantly higher in Group II versus Group I (11.93 vs. 4.48 ng/mL, p < 0.001). Ferritin and CRP values showed similar patterns in IBD patients: significantly higher levels were observed in Group II (47.5 ng/mL and 13.68 mg/L) than in Group I (11.0 ng/mL and 3.39 mg/L) (p < 0.001). In Group II, hepcidin-25 was positively correlated with ferritin (ρ = 0.725, p < 0.001) and CRP (ρ = 0.502, p = 0.003). Ferritin was an independent variable influencing hepcidin-25 concentration in IBD patients, regardless of disease activity and severity of anemia. IBD hepcidin-25 best correlates with ferritin, and both parameters reflected inflammation extent and IBD activity.

Can serum ferritin serve as a biomarker for the prognosis of gynecological malignant tumors? A retrospective cohort study

PURPOSE

It is widely accepted that there is a strong relationship between iron levels and cancer. This study aimed to investigate the relationship between serum ferritin levels and the severity and prognosis of gynecological malignant tumors.

METHODS

This retrospective study included patients with gynecological malignant tumors at Sir Run Run Shaw Hospital in the Department of Obstetrics and Gynecology from January 2013 to June 2019. Patients were grouped according to their serum ferritin level: low (< 13 μg/L), normal (13-150 μg/L), and high (> 150 μg/L). Correlation analyses were performed between serum ferritin level and other factors. Cox univariable and multivariable analysis and Kaplan-Meier survival curves were used to assess the impact of ferritin on survival in patients with gynecologic tumors.

RESULTS

The 402 total patients were divided into a low (n= 37), normal (n= 182), and high (n= 183) ferritin level group. Correlation analyses were performed that WBC, MCV, CRP, CA125, and CA153 were significantly positively correlated with serum ferritin level. The Kaplan-Meier survival curves revealed that of the three groups analyzed, the high serum ferritin level group had a significantly shorter survival time versus the normal and low serum ferritin level groups (log-rank P= 0.003). Univariable Cox regression analysis identified that patients with high serum ferritin levels had a significant correlation with risk of death compared to the patients with lower and normal serum ferritin levels. Serum ferritin was not found to be significant (HR = 0.792, 95% CI: 0.351-1.787, P= 0.574) in the multivariable Cox analysis.

CONCLUSION

Although this study did not find serum ferritin to be a significant independent prognosis indicator in gynecological malignant tumors, this study did identify that gynecological malignant tumor patients with high serum ferritin levels have significantly less survival time than patients with low or normal serum ferritin levels.

Progression of Diabetic Kidney Disease and Gastrointestinal Symptoms in Patients with Type I Diabetes

(1) Background: Little research is conducted on the link between diabetic kidney disease (DKD) progression and diabetic gastroenteropathy in type 1 diabetes (T1D). (2) Methods. We performed a cross-sectional study with 100 T1D patients; 27 of them had progressive DKD, defined as an estimated glomerular filtration rate (eGFR) decline ≥3 mL/min/year or increased albuminuria stage, over a mean follow-up time of 5.89 ± 1.73 years. A newly developed score with 17 questions on gastrointestinal (GI) symptoms was used. Faecal calprotectin was measured by ELISA. Lower GI endoscopies were performed in 21 patients. (3) Results: The gastrointestinal symptom score demonstrated high reliability (Cronbach's α = 0.78). Patients with progressive DKD had higher GI symptom scores compared to those with stable DKD (p = 0.019). The former group demonstrated more frequent bowel movement disorders (p < 0.01). The scores correlated negatively with eGFR (r = -0.335; p = 0.001), positively with albuminuria (r = 0.245; p = 0.015), Hba1c (r = 0.305; p = 0.002), and diabetes duration (r = 0.251; p = 0.012). Faecal calprotectin levels did not differ between DKD groups significantly. The most commonly reported histopathological findings of enteric mucosa were infiltration with eosinophils, lymphocytes, plasmacytes, the presence of lymphoid follicles, and lymphoid aggregates. Conclusion: The progression of DKD is positively correlated with gastrointestinal symptoms; however, more research is needed to clarify the causal relationships of the gut-kidney axis in T1D.

Single-Center Analysis of Essential Laboratory Testing in Patients with Newly Diagnosed Celiac Disease

OBJECTIVE

To analyze laboratory testing results from pediatric patients newly diagnosed with celiac disease to determine the usefulness of each test derived from recommended guidelines.

METHODS

Serological testing at the time of diagnosis from patients enrolled in our celiac disease registry from January 2018 through December 2021 was reviewed. The incidence of abnormal laboratory results, routinely obtained as per the recommendations of Snyder et al and our institution's Celiac Care Index, was assessed. Rates of abnormal laboratory values and estimated costs associated with these screening measures were analyzed.

RESULTS

Our data demonstrated abnormalities in all serological testing obtained at celiac diagnosis. Hemoglobin, alanine aminotransferase, ferritin, iron, and vitamin D screening were found to be abnormal with notable frequency. Only 7% of patients had an abnormal thyroid-stimulating hormone and <0.1% had an abnormal free T4. Nonresponse to hepatitis B vaccination was prominent, with 69% of patients considered nonimmune. Screening protocols as currently outlined in our Celiac Care Index resulted in an estimated cost of approximately $320 000 during our study.

CONCLUSIONS

Review of screening laboratory results at our center reveals that abnormal values for several recommended measures are uncommon. Thyroid screening was infrequently abnormal and the usefulness of screening for hepatitis B at diagnosis is uncertain. Similarly, our data suggest that iron deficiency screening may be condensed effectively into hemoglobin and ferritin testing, eliminating the need for initial iron studies. Decreasing baseline screening measures could safely decrease the burden of testing on patients and overall healthcare expenditures.

Defining an optimal cut-off point for reticulocyte hemoglobin as a marker for iron deficiency anemia: An ROC analysis

Reticulocyte hemoglobin (CHr) is a measure of the amount of hemoglobin in reticulocytes and a marker of cell hemoglobinization. In this study, we aimed to find the optimal cut-off point for reticulocyte hemoglobin to diagnose iron deficiency anemia using multiple methods. A total of 309 patients were included. The median age at diagnosis was 54 years. Most were females (71.2%). 68% had iron deficiency anemia. Patients with IDA had significantly lower levels of CHr compared to those who had non-IDA (p < 0.0001). The optimal cut-off value of CHr for detecting IDA, determined using various methods, was 30.15 pg. This cut-off point had a sensitivity of 87.8% and a specificity of 77.7%. CHr showed a significant positive correlation with hemoglobin, mean corpuscular volume, serum iron, serum ferritin, and transferrin saturation and a significant negative correlation with total iron-binding capacity. CHr levels correlate with most established laboratory tests for IDA. It reliably detects IDA. Our results indicate the importance of CHr in diagnosing IDA, and that CHr should be used more widely in suspected cases of IDA since it is a cheap, fast, and reliable test.

Iron deficiency in sepsis patients managed with divided doses of iron dextran: a prospective cohort study

Iron deficiency (ID) impairs hemoglobin (Hb) synthesis and immune function, both crucial for sepsis patients. We assessed the impact of iron dextran on reticulocyte (Ret) Hb equivalent (Ret-He) and Ret subpopulations in iron-deficient sepsis patients. In this prospective clinical study we enrolled patients with sepsis or septic shock with procalcitonin concentration > 0.5 ng/mL, diagnosed with ID based on Ret-He. Study subjects received divided doses of iron dextran until normalization of Ret-He. The study population included 35 subjects. The median Ret-He increase after 2 doses of iron dextran was 3.0 (IQR 1.9-6.1) pg (p < 0.01) with median time to normalization 4 (IQR 3-5) days. Although no change in Ret percentage [Me 1.5 (IQR 1.1-2.1) vs. Me 1.4 (IQR 1.1-2.4) %, p = 0.39] and number [Me 0.05 (IQR 0.04-0.07) vs. Me 0.05 (IQR 0.03-0.06) 10⁶/µL, p = 0.88] was noted, Ret subpopulations changed significantly (p for all < 0.01). Divided doses of iron dextran relatively quickly normalize Ret-He in iron-deficient sepsis patients. Changes in Ret subpopulations suggest increased erythropoietic activity. Further research is needed to explore the role of intravenous iron in this clinical setting.

Evaluation of Serum Iron Parameters among Men Performing Regular Physical Activity—A Preliminary Study

Iron deficiency anemia is one of the most common issues in clinical practice. It can be caused by intense physical activity, among other things. The aim of the study was to assess serum iron parameters in a group of men who engage in regular physical activity. The study group was composed of 20 men who regularly perform strength or endurance sports, whereas the control group consisted of 20 men without any sports activity. The red blood cell (RBC) parameters, platelet count (PLT), and white blood cell (WBC) count in venous blood samples were assessed with an automated hematology analyzer. The serum concentration of ferritin was determined through an immunology assay. There were no statistically significant differences between groups comparing RBC parameters and WBC. However, statistical analysis showed dissimilarity in PLT count and serum ferritin concentration comparing control and study groups (p < 0.05). It was shown that lower serum ferritin concentration concerns men with regular physical activity, whereas other blood parameters were not affected in this group.

The Role of Selected Serpins in Gastrointestinal (GI) Malignancies

Gastrointestinal (GI) cancers, which are a diverse group of malignant diseases, represent a major healthcare problem around the world. Due to the lack of specific symptoms in the early stages as well as insufficient diagnostic possibilities, these malignancies occupy the leading position in the causes of death worldwide. The currently available tests have too many limitations to be part of routine diagnostics. Therefore, new potential biomarkers that could be used as diagnostic and prognostic factors for these cancers are still being sought. Among the proteins that might fit this role are serpins, which are serine protease inhibitors. Although the serpins themselves have been known for many years, they have recently become the centre of attention for many authors, especially due to the fact that a number of proteins in this family are involved in many stages of neoplasia formation, from angiogenesis through tumour growth to progression. Therefore, the aim of this review is to present the current knowledge about the significance of serpins in GI malignancies, especially their involvement in the development and progression of oesophageal, gastric, pancreatic and colorectal cancers. This review summarises and confirms the important roles of selected serpins in the pathogenesis of various GI cancers and also points to their promising roles as therapeutic targets. However, due to the relatively nonspecific nature of serpins, future research should be carried out to elucidate the mechanisms involved in tumour pathogenesis in more detail.

Fecal Iron Measurement in Studies of the Human Intestinal Microbiome

Iron is an essential micronutrient for humans and their intestinal microbiota. Host intestinal cells and iron-dependent bacteria compete for intraluminal iron, so the composition and functions of the gut microbiota may influence iron availability. Studies of the effects of the microbiota or probiotic interventions on host iron absorption may be particularly relevant to settings with high burdens of iron deficiency and gastrointestinal infections, since inflammation reduces iron bioavailability and unabsorbed intraluminal iron may modify the composition of the microbiota. The quantification of stool iron content may serve as an indicator of the amount of intraluminal iron to which the intestinal microbiota is exposed, which is particularly relevant for studies of the effect of iron on the intestinal microbiome, where fecal samples collected for purposes of microbiome characterization can be leveraged for stool iron analysis. However, few studies are available to guide researchers in the selection and implementation of stool iron assays, particularly because cross-comparison of available methods is limited in literature. This review aims to describe the available stool iron quantification methods and highlight their potential application in studies of iron-microbiome relationships, with a focus on pediatric research. MS-based methods offer high sensitivity and precision, but the need for expensive equipment and the high per-sample and maintenance costs may limit their widespread use. Conversely, colorimetric assays offer lower cost, ease of use, and rapid turnaround times but have thus far been optimized primarily for blood-derived matrices rather than stool. Further research efforts are needed to validate and standardize methods for stool iron assessment and to determine if the incorporation of such analyses in human microbiome studies 1) yields insights into the interactions between intestinal microbiota and iron and 2) contributes to the development of interventions that mitigate iron deficiency and promote a healthy microbiome.

Chronic Fatigue Syndrome in Patients with Deteriorated Iron Metabolism

Fatigue is a common, non-specific symptom that often impairs patients’ quality of life. Even though fatigue may be the first symptom of many serious diseases, it is often underestimated due to its non-specific nature. Iron metabolism disorders are a prominent example of conditions where fatigue is a leading symptom. Whether it is an iron deficiency or overload, tiredness is one of the most common features. Despite significant progress in diagnosing and treating iron pathologies, the approach to chronic fatigue syndrome in such patients is not precisely determined. Our study aims to present the current state of knowledge on fatigue in patients with deteriorated iron metabolism.

Endothelin A receptor antagonist attenuated renal iron accumulation in iron overload heme oxygenase-1 knockout mice

Progressive iron accumulation and renal impairment are prominent in both patients and mouse models of sickle cell disease (SCD). Endothelin A receptor (ETA) antagonism prevents this iron accumulation phenotype and reduces renal iron deposition in proximal tubules of SCD mice. To better understand the mechanisms of iron metabolism in the kidney and the role of ETA receptor in iron chelation and transport, we studied renal iron handling in a non-sickle cell iron overload model, heme oxygenase-1 (Hmox-1-/-) knockout mice. We found that Hmox-1-/- mice had elevated plasma endothelin-1 (ET-1), cortical ET-1 mRNA expression, and renal iron content compared to Hmox-1+/+ controls. The ETA receptor antagonist, ambrisentan, attenuated renal iron deposition, without any changes to anemia status in Hmox-1-/- mice. This was accompanied by reduced urinary iron excretion. Finally, ambrisentan had an important iron recycling effect by increasing expression of cellular iron exporter, ferroportin-1 (FPN-1) and circulating total iron levels in Hmox-1-/- mice. These findings suggest the ET-1/ETA signaling pathway contributes to in renal iron trafficking in a murine model of iron overload.

The modulation of Plasma Levels of Dopamine, Serotonin, and Brain-derived neurotrophic factor in response to variation in iron availability

BACKGROUND AND AIM

In the context of iron deficiency anemia, central dopamine, serotonin, and brain-derived neurotrophic factor (BDNF) are intensively investigated. However, peripheral isoforms are poorly investigated. This study aimed to investigate the modulation of plasma levels of dopamine, serotonin, and BDNF among children with iron deficiency anemia.

METHODS

A total of seventy-three iron-deficient (n=38) and iron-sufficient (n=35) children were included in the study.  Twenty-nine subjects were showing clinical presentations and were diagnosed with iron deficiency anemia and forty-four were asymptomatic normal children. Plasma levels of dopamine, serotonin, and brain-derived neurotrophic factor were determined by enzyme-linked immunosorbent assay.

RESULTS

As compared to corresponding levels among control subjects, Anemic subjects were having significantly higher plasma dopamine and lower plasma brain-derived neurotrophic factor levels. A significant linear and monotonic association of plasma dopamine and brain-derived neurotrophic factor with hemoglobin concentration (r=-0.520, P < 0.001 and ρ = 0.411, P = 0.001), respectively. Furthermore, there were significantly higher plasma serotonin levels among iron-deficient subjects with a significant inverse linear association with serum ferritin levels (r = -0.337, P = 0.005).

CONCLUSIONS

Iron deficiency anemia is associated with the modulation of peripheral dopamine, serotonin, and brain-derived neurotrophic factor. Upregulation of dopamine and downregulation of brain-derived neurotrophic factor are correlated to the anemic status. The upregulation of plasma serotonin levels is iron-dependent and, probably, is attributed to the impairment of its metabolic fate. Further investigation is required to explore the pathophysiological and clinical association of these peripheral biomolecules in the context of iron deficiency anemia. (www.actabiomedica.it).

Prevalence of iron deficiency in pregnant women: A prospective cross-sectional Austrian study

The aim of the study was to determine, for the first time, in a prospective cross-sectional multicenter study, the prevalence of iron deficiency (ID) in an Austrian pregnant population. A cohort of 425 pregnant women was classified into four groups of different weeks of gestation. Group 1 was monitored longitudinally, while groups 2-4, iron status, were sampled only once. Evaluation of the prevalence of ID was performed by comparing the diagnostic criteria of the WHO to the cutoff proposed by Achebe MM and Gafter-Gvili A (Achebe) and the Austrian Nutrition Report (ANR). In comparison with the ANR, the prevalence of ID was lower in group 1 and higher in groups 2-4 (17.2% vs. 12.17%, 25.84%, 35.29%, and 41.76%, respectively) (p-values < .01 except group 1). According to WHO, the prevalence in group 1 was 12.17% at inclusion, 2 months later 31.7%, and further 2 months later 65.71%, respectively. According to Achebe, the number of cases doubled; for group 1, the number of cases rose from 13 to 42 (115 patients total); for groups 2-4, we observed an increase from 112 to 230 (340 patients total). This study reported a prevalence of around 12% at the beginning of pregnancy, which increased during pregnancy up to 65%. ID can have a massive impact on quality of life, justifying screening, as iron deficiency would be easy to diagnose and treat.

Reticulocyte Hemoglobin Equivalent: Diagnostic Performance in Assessment of Iron Deficiency in Patients with Hypothyroidism

Introduction

Iron deficiency affects approximately 30% of the world population and is frequently encountered in hypothyroid patients. Early recognition and prompt treatment of iron deficiency in hypothyroid patients lead to a favorable outcome. The aim of this study is to prove the usefulness of reticulocyte hemoglobin equivalent (Ret-He) as a reliable and effective tool in diagnosis of iron deficiency in hypothyroid patients.

Materials and Methods

154 patients with hypothyroidism were included in the study. They were divided into 4 groups. Group 1 included 66 hypothyroid patients without iron deficiency. They were taken as controls. Group 2 included 66 hypothyroid patients with iron deficiency anemia (IDA). Group 3 included 12 hypothyroid patients with iron deficiency but without anemia (ID). Group 4 included 10 hypothyroid patients which had concomitant iron deficiency with anemia of chronic disorder (ACDC). Ret-He was measured by analyzing blood samples on System XN 350. Thyroid profile, serum ferritin, and biochemical data were measured by an automated analyzer. Statistical analysis was performed by using SPSS 23.

Results

Ret-He was significantly lower with (p < 0.001) in group 2 (hypothyroid patients with IDA), group 3 (hypothyroid patients with ID), and in group 4 (hypothyroid patients with ACDC) as compared to controls in group 1 (hypothyroid patients without iron deficiency). After ROC analysis area under the curve (AUC) of Ret-He for hypothyroid patients with IDA was 0.96 at cutoff 28.5 pg with sensitivity of 93% and specificity of 90%. AUC of Ret-He in the hypothyroid group with ACDC was 0.99 at cutoff 30.8 pg with sensitivity of 90% and specificity of 90%. AUC of Ret-He in hypothyroid patients with ID was 0.97 at cutoff 31.7 pg with sensitivity of 91% and specificity of 70%.

Conclusion

Ret-He is a reliable, rapid, and cost-effective tool for diagnosing iron deficiency in hypothyroid patients.

The Impact of Vegan and Vegetarian Diets on Physical Performance and Molecular Signaling in Skeletal Muscle

Muscular adaptations can be triggered by exercise and diet. As vegan and vegetarian diets differ in nutrient composition compared to an omnivorous diet, a change in dietary regimen might alter physiological responses to physical exercise and influence physical performance. Mitochondria abundance, muscle capillary density, hemoglobin concentration, endothelial function, functional heart morphology and availability of carbohydrates affect endurance performance and can be influenced by diet. Based on these factors, a vegan and vegetarian diet possesses potentially advantageous properties for endurance performance. Properties of the contractile elements, muscle protein synthesis, the neuromuscular system and phosphagen availability affect strength performance and can also be influenced by diet. However, a vegan and vegetarian diet possesses potentially disadvantageous properties for strength performance. Current research has failed to demonstrate consistent differences of performance between diets but a trend towards improved performance after vegetarian and vegan diets for both endurance and strength exercise has been shown. Importantly, diet alters molecular signaling via leucine, creatine, DHA and EPA that directly modulates skeletal muscle adaptation. By changing the gut microbiome, diet can modulate signaling through the production of SFCA.

Impact of hookworm infection and preventive chemotherapy on haemoglobin in non-pregnant populations

OBJECTIVE

To assess the impact of hookworm infection and preventive chemotherapy on haemoglobin levels in non-pregnant populations in endemic areas.

METHOD

Systematic review and meta-analysis searching PubMed and Web of Science for articles published since 2010 reporting either hookworm prevalence and Hb concentration (cross-sectional studies) or Hb concentration before and after the implementation of preventive chemotherapy (before-after studies and randomised controlled trials [RCTs]). For papers published before 2010, data were extracted from a previously published systematic review. Random effects meta-analyses were conducted to examine the relationship between Hb concentration and hookworm infection intensity (from cross-sectional studies) and the effect of preventive chemotherapy on Hb concentration (from before-after studies and RCTs). Sensitivity analyses investigated the impact of malaria endemicity and combined interventions for schistosomiasis and nutrition status on Hb concentration.

RESULTS

Among cross-sectional studies, both light- and heavy-intensity hookworm infections were associated with lower Hb in school-aged children. School-aged children with heavy hookworm infection in settings of high malaria endemicity had lower mean Hb than those in settings of low malaria endemicity. In non-pregnant populations, deworming with albendazole was associated with an increase in Hb of 3.02 g/L (95% CI 0.1, 6.0 g/L). No additional benefit was seen with deworming using albendazole co-administered with praziquantel for schistosomiasis infection or iron supplementation for nutrition status.

CONCLUSION

Our findings confirm the benefits of preventive chemotherapy as a public health intervention.

Insufficient classification of anaemia in general practice: a Danish register-based observational study

BACKGROUND

Anaemia can be a pointer of underlying severe disease, including undiagnosed malignancy. Subsequent blood tests are essential to classify the anaemia into subtypes and to facilitate targeted diagnostic investigation to ensure timely diagnosis of underlying disease.

OBJECTIVE

We aimed to describe and classify anaemia based on laboratory tests from patients with new-onset anaemia detected in general practice. An additional aim was to analyse associations between patient characteristics and unclassified anaemia (not classifiable according to an algorithm).

DESIGN

Population-based cross-sectional study.

SETTING

Danish general practice.

SUBJECTS

A total of 62,731 patients (age: 40-90 years) with new-onset anaemia were identified in Danish laboratory information systems and nationwide registries, and data were obtained for 2014-2018.

MAIN OUTCOME MEASURES

We measured the proportion of patients classified into subtypes of anaemia based on blood tests requested by general practitioners within 31 days of the anaemia index date.

RESULTS

Of the 62,731 patients with new-onset anaemia, we identified unclassified anaemia in 78.9% (95% confidence interval (CI): 77.3-80.5) of men and 65.1% (CI: 63.4-66.9) of women. The likelihood of unclassified anaemia increased with age, increasing comorbidity and decreasing severity of anaemia.

CONCLUSION

The majority of patients with new-onset anaemia could not be classified through a simple algorithm due to missing blood tests, which highlights a potential missed opportunity for diagnosis. Standardised laboratory testing of patients with anaemia is warranted to ensure adequate follow-up and early detection of underlying severe disease.KEY POINTSAnaemia can be a sign of malignancy, and anaemia classification is an important step in the diagnosis of underlying disorders.The majority of patients with anaemia could not be classified according to a simple algorithm due to missing blood tests.Some patient characteristics were associated with a high risk of unclassified anaemia: high age, high comorbidity, and severe anaemia.Standardised laboratory testing in patients with anaemia is needed to inform targeted diagnostic investigation to ensure timely diagnosis.

Are There Ethnic Differences in Micronutrient Deficiencies in Preoperative Bariatric Patients? A Systematic Review and Meta-analysis

The purpose of this systematic review was to determine if in patients presenting for bariatric surgery, patients of different ethnicities, have different micronutrient deficiencies preoperatively. Databases searched were PubMed, Embase, MEDLINE and Cochrane Library. A meta-analysis of prevalence of vitamin D insufficiency (<20ng/ml) was carried out using a random effects model. Twenty-eight articles were included assessing preoperative micronutrient status across different ethnic groups. The most common micronutrient assessed was vitamin D, and the most assessed ethnicity was Caucasian. African Americans had the greatest prevalence of vitamin D insufficiency when compared to other ethnicities with a pooled prevalence and 95% confidence interval of 0.80 [0.74; 0.85]. There was a significant difference in vitamin D insufficiency when compared across ethnicities (p <0.01).

Helicobacter pylori infection and micronutrient deficiency in pregnant women: a systematic review and meta-analysis

Background

Over the last few years, epidemiological studies have shown that infection with Helicobacter pylori has a major effect on micronutrient deficiency as well as on adverse pregnancy outcomes. Importantly, there are gaps in understanding the linkage of H. pylori infection with micronutrients deficiency in pregnant women.

Objective

We conducted a systematic review and meta-analysis to estimate the association between H. pylori infection and micronutrient deficiencies in pregnant women.

Methods

A systematic literature search was conducted for relevant articles using PubMed, Web of Science, and Scopus database from inception to March 2020. The OR with 95% CIs was determined by meta-analysis of data extracted from the selected studies.

Results

From 2384 primary articles, 6 studies were selected for systematic reviews and 4 studies distinctively (with 1274 participants: 553 cases and 721 controls) were selected for meta-analysis. The meta-analysed fixed effect model estimated the odds of having H. pylori infection was not significantly higher among pregnant women with micronutrient deficiencies than those without deficiencies (OR=1.12, 95% CI 0.88 to 1.42, p=0.37). In the subgroup analysis, no correlation was found between H. pylori infection and vitamin B₁₂ (OR=0.74, 95% CI 0.45 to 1.21, p=0.22), folate (OR=1.07, 95% CI 0.73 to 1.58, p=0.73), and ferritin (OR=0.81, 95% CI 0.51 to 1.31, p=0.4). However, a positive correlation was found between iron-deficiency anaemia (IDA) and H. pylori infection (OR=16.23, 95% CI 4.19 to 62.93, p<0.0001) during pregnancy.

Conclusion

H. pylori infection is associated with increased risk of IDA but not with deficiency of other micronutrients in pregnancy.

PROSPERO registration number

CRD42019135683.

Celiac disease in children: Increasing prevalence and changing clinical presentations

BACKGROUND

Celiac disease (CD) is a chronic autoimmune enteropathy. It results from genetic predisposition and exposure to gluten-containing food. The prevalence and presentation of CD vary among populations.

PURPOSE

This study aimed to describe the prevalence and clinical characteristics of CD in children in Bahrain.

METHODS

We retrospectively reviewed the medical records of children diagnosed with CD in the pediatric department, Salmaniya Medical Complex, Bahrain, in 1988-2018. Their clinical, biochemical, serological, and histopathological findings were documented. Adherence to the recommended gluten-free diet (GFD) was assessed.

RESULTS

Of 86 patients with CD, 67 were included. The CD prevalence was 0.02%. A significant increase in prevalence in the last decade was observed (P<0.0001). Thirty-eight patients (56.7%) were males. The median (interquartile range) age at presentation was 4.45 (1.5-7.3) years. A family history of CD was positive in 13 out of 43 patients (30.2%). Pallor and failure to thrive were the most common presentations. The most frequent associated disease was iron-deficiency anemia in 23 patients (69.7%). Positive serology was found in 32 of 45 patients (71.1%). Marsh-Oberhuber type III was found in 16 of 35 patients (45.7%). Seropositive patients were significantly older (P=0.025) and had more severe duodenal histology (P=0.002). Adherence to GFD was poor in 27 patients (64.3%).

CONCLUSION

This study revealed a significant increase in CD prevalence over the last decade. Atypical presentations were frequent. Most patients had poor adherence to GFD.

Prevalence and Factors Associated with Iron Deficiency and Anemia among Residents of Urban Areas of São Paulo, Brazil

Anemia is a worldwide concern. This cross-sectional population-based study examined the prevalence of iron-deficiency anemia (IDA) among residents of São Paulo (n = 898; 12-93 years), considering sociodemographic factors, dietary iron inadequacy, and food contributors to iron intake. Blood cell count and iron biomarkers were quantified. Dietary iron intake was measured using two 24-h dietary recalls. Iron intake inadequacy was estimated using a probabilistic approach. The prevalence of anemia was 6.7%, depleted iron stores 5.1%, and IDA 1.1%. Women of all age groups, older adults, and those who were underweight or obese had the highest prevalence of anemia, and female adolescents had the highest prevalence of depleted iron stores. Female adolescents and adults were more vulnerable to depleted iron stores. Male adults and older adults had a considerable prevalence of iron overload. Except for female adolescents and adults, all groups had mild probabilities of inadequate iron intake. The main food iron contributor was wheat flour. Hemoglobin concentrations were directly associated with being an adult, having a higher income, and inversely associated with being female. Serum ferritin concentrations were directly associated with age and inversely correlated with female sex. Residents of São Paulo had a low prevalence of anemia, iron deficiency, and IDA, and sociodemographic factors interfered with these parameters.

The use of faecal immunochemical testing in the decision-making process for the endoscopic investigation of iron deficiency anaemia

Background Blood loss from the gastrointestinal (GI) tract is the most common cause of iron deficiency anaemia (IDA) in adult men and postmenopausal women. Gastroduodenal endoscopy (GDE) and colonoscopy are frequently recommended, despite uncertainty regarding the coexistence of lesions in the upper and lower GI tract. The faecal immunochemical test (FIT) measures the concentration of faecal haemoglobin (f-Hb) originating only from the colon or rectum. We aimed to assess whether the FIT was able to select the best endoscopic procedure for detecting the cause of IDA. Methods A prospective study of 120 men and postmenopausal women referred for a diagnostic study of IDA were evaluated with an FIT, GDE and colonoscopy. The endoscopic finding of a significant upper lesion (SUL) or a significant bowel lesion (SBL) was considered to be the cause of the IDA. Results The diagnoses were 35.0% SUL and 20.0% SBL, including 13.3% GI cancer. In the multivariate analysis, the concentration of blood haemoglobin (b-Hb) <9 g/dL (OR: 2.60; 95% CI 1.13-6.00; p = 0.025) and non-steroidal anti-inflammatory drugs NSAIDs (2.56; 1.13-5.88; p = 0.024) were associated with an SUL. Age (0.93; 0.88-0.99; p = 0.042) and f-Hb ≥ 15 μg Hb/g faeces (38.53; 8.60-172.50; p < 0.001) were associated with an SBL. A "FIT plus gastroscopy" strategy, in which colonoscopy is performed only when f-Hb ≥15 μg Hb/g faeces, would be able to detect 92.4% of lesions and be 100% accurate in the detection of cancer while avoiding 71.6% of colonoscopies. Conclusions The FIT is an accurate method for selecting the best endoscopy study for the evaluation of IDA. An FIT-based strategy is more cost-effective than the current bidirectional endoscopy-based strategy and could improve endoscopic resource allocation.

Single-cell O2 exchange imaging shows that cytoplasmic diffusion is a dominant barrier to efficient gas transport in red blood cells

Blood is routinely tested for gas-carrying capacity (total hemoglobin), but this cannot determine the speed at which red blood cells (RBCs) exchange gases. Such information is critical for evaluating the physiological fitness of RBCs, which have very limited capillary transit times (<1 s) for turning over substantial volumes of gas. We developed a method to quantify gas exchange in individual RBCs and used it to show that restricted diffusion, imposed by hemoglobin crowding, is a major barrier to gas flows. Consequently, hematological disorders manifesting a change in cell shape or hemoglobin concentration have uncharted implications on gas exchange, which we illustrate using inherited anemias. With its single-cell resolution, the method can identify physiologically inferior subpopulations, providing a clinically useful appraisal of blood quality.

Disorders of oxygen transport are commonly attributed to inadequate carrying capacity (anemia) but may also relate to inefficient gas exchange by red blood cells (RBCs), a process that is poorly characterized yet assumed to be rapid. Without direct measurements of gas exchange at the single-cell level, the barriers to O₂ transport and their relationship with hematological disorders remain ill defined. We developed a method to track the flow of O₂ in individual RBCs by combining ultrarapid solution switching (to manipulate gas tension) with single-cell O₂ saturation fluorescence microscopy. O₂ unloading from RBCs was considerably slower than previously estimated in acellular hemoglobin solutions, indicating the presence of diffusional barriers in intact cells. Rate-limiting diffusion across cytoplasm was demonstrated by osmotically induced changes to hemoglobin concentration (i.e., diffusive tortuosity) and cell size (i.e., diffusion pathlength) and by comparing wild-type cells with hemoglobin H (HbH) thalassemia (shorter pathlength and reduced tortuosity) and hereditary spherocytosis (HS; expanded pathlength). Analysis of the distribution of O₂ unloading rates in HS RBCs identified a subpopulation of spherocytes with greatly impaired gas exchange. Tortuosity imposed by hemoglobin was verified by demonstrating restricted diffusivity of CO₂, an acidic gas, from the dissipative spread of photolytically uncaged H⁺ ions across cytoplasm. Our findings indicate that cytoplasmic diffusion, determined by pathlength and tortuosity, is a major barrier to efficient gas handling by RBCs. Consequently, changes in RBC shape and hemoglobin concentration, which are common manifestations of hematological disorders, can have hitherto unrecognized and clinically significant implications on gas exchange.