An insight into the relationships between prohepcidin, iron deficiency anemia, and interleukin-6 values in pediatric Helicobacter pylori gastritis

Helicobacter pylori-Associated Iron Deficiency Anemia in Childhood and Adolescence-Pathogenesis and Clinical Management Strategy

Many epidemiological studies and meta-analyses show that persistent Helicobacter pylori infection in the gastric mucosa can lead to iron deficiency or iron deficiency anemia (IDA), particularly in certain populations of children and adolescents. Moreover, it has been demonstrated that H. pylori infection can lead to and be closely associated with recurrent and/or refractory iron deficiency and IDA. However, the pathogenesis and specific risk factors leading to this clinical outcome in H. pylori-infected children remain poorly understood. In general, most of pediatric patients with H. pylori-associated IDA do not show evidence of overt blood loss due to gastrointestinal hemorrhagic lesions. In adult populations, H. pylori atrophic gastritis is reported to cause impaired iron absorption due to impaired gastric acid secretion, which, subsequently, results in IDA. However, significant gastric atrophy, and the resultant substantial reduction in gastric acid secretion, has not been shown in H. pylori-infected children. Recently, it has been hypothesized that competition between H. pylori and humans for iron availability in the upper gastrointestinal tract could lead to IDA. Many genes, including those encoding major outer membrane proteins (OMPs), are known to be involved in iron-uptake mechanisms in H. pylori. Recent studies have been published that describe H. pylori virulence factors, including specific OMP genes that may be associated with the pathogenesis of IDA. Daily iron demand substantively increases in children as they begin pubertal development starting with the associated growth spurt, and this important physiological mechanism may play a synergistic role for the microorganisms as a host pathogenetic factor of IDA. Like in the most recent pediatric guidelines, a test-and-treat strategy in H. pylori infection should be considered, especially for children and adolescents in whom IDA is recurrent or refractory to iron supplementation and other definitive causes have not been identified. This review will focus on providing the evidence that supports a clear biological plausibility for H. pylori infection and iron deficiency, as well as IDA.

Helicobacter pylori-Related Extraintestinal Manifestations—Myth or Reality

It is well documented that Helicobacter pylori (H. pylori) can cause both gastrointestinal and extraintestinal manifestations. The latter one represents a major burden in terms of diagnosis and treatment. H. pylori-associated systemic subclinical inflammation is mostly responsible for the development of extraintestinal manifestations, and its early eradication might result in preventing all adverse events related to their occurrence. Thus, it was suggested that H. pylori might be associated with iron deficiency anemia, thrombocytopenia (immune thrombocytopenic purpura), Schonlein Henoch purpura, failure to thrive, vitamin B12 deficiency, diabetes mellitus, body mass index, cardiovascular diseases, as well as certain neurological conditions. Nevertheless, studies showed both pros and cons in terms of the role of H. pylori in the development of previously mentioned clinical entity underlining the crucial need for further studies on these topics. Although most of these extraintestinal manifestations occur during adulthood, we must not forget that H. pylori infection is acquired mainly during childhood, and thus its early diagnosis and eradication might represent the cornerstone in the prevention of H. pylori-induced inflammatory status and consequently of all related extraintestinal conditions.

Persistent Iron Deficiency Anemia in Patients with Celiac Disease Despite a Gluten-Free Diet

Celiac disease (CD) is an autoimmune disorder characterized by intolerance to dietary gluten in genetically predisposed subjects. Iron deficiency anemia (IDA) is a common sign in CD, being the only abnormality in approximately 40% of celiac patients. A multifactorial etiology leads to IDA in CD. The two main causes are the villous atrophy of the mucosa at the site of iron absorption (the duodenum) and the resulting inflammation, which triggers the mechanism that leads to the anemia of chronic disease. Until now, it has been unclear why some patients with CD continue to have IDA despite a careful gluten-free diet (GFD) and the normalization of villous atrophy. Furthermore, some celiac patients are refractory to oral iron supplementation despite the healing of the mucosa, and they thus require periodic intravenous iron administration. The Marsh classification evaluates the degree of inflammation and villous atrophy, but it does not assess the possible persistence of ultrastructural and molecular alterations in enterocytes. The latter was found in CD in remission after adopting a GFD and could be responsible for the persistently reduced absorption of iron and IDA. Even in non-celiac gluten sensitivity, anemia is present in 18.5-22% of patients and appears to be related to ultrastructural and molecular alterations in intestinal microvilli. It is possible that a genetic component may also play a role in IDA. In this review, we evaluate and discuss the main mechanisms of IDA in CD and the possible causes of its persistence after adopting a GFD, as well as their therapeutic implications.

Classic and emergent indicators for the assessment of human iron status

Iron deficiency is the leading cause of anemia, a significant global public health problem. Different methods exist for assessing iron nutritional status, including laboratory tests that focus on storage, transportation, and iron functional compartment parameters. Classical markers such as bone marrow, serum iron, ferritin, hemoglobin, erythrocyte parameters, transferrin, transferrin receptors, and zinc protoporphyrin are discussed in this review. Additional parameters calculated from these indicators, including transferrin saturation, ferritin index and Thomas plot, and some emergent parameters such as hepcidin, erythroferrone, and low hemoglobin density are also discussed. There is no a single indicator for assessing iron nutritional status. Therefore, the use of more than one indicator may be the best practice to obtain the correct diagnosis, also considering the influence of inflammation/infection on many of these indicators. The constant validation of the current parameters, the improvement of assessment methods, and the identification of new indicators will be the key to refine the assessment of iron nutritional status and the right choice of treatment for its improvement.

Iron status determination in individuals with Helicobacter pylori infection: conventional vs. new laboratory biomarkers

Background Helicobacter pylori has been associated with iron deficiency (ID). This study is aimed at investigating ID with conventional (ferritin, transferrin saturation [TSAT]) and new biomarkers (soluble transferrin receptor [sTfR], sTfR/log ferritin, reticulocyte hemoglobin content [CHr], hepcidin-25) in patients sub-grouped by the presence or absence of H. pylori infection. Methods In total, 200 consecutive outpatients, who were referred for the H. pylori 13C-urea breath test (13C-UBT), underwent blood testing for ID. Additionally, Thomas-plot (TP)-analyses (sTfR/log ferritin, CHr) were calculated. Results Fifty-three and 147 individuals were found with and without H. pylori infection, respectively. Patients with H. pylori infection showed a higher sTfR concentration (p<0.02) and a higher sTfR/log ferritin ratio (p<0.05). Based on a ferritin <30 μg/L and/or a TSAT <20%, 25/53 (47.2%) patients with H. pylori infection and 63/147 (42.9%) without H. pylori infection showed ID. Based on TP-analyses, 10/53 (18.9%) patients with and 17/147 (11.6%) without H. pylori infection were identified with ID. Completed eradication therapy tended to be associated with functional ID. Conclusions Helicobacter pylori infection was associated with significantly higher plasma sTfR concentrations and sTfR/log ferritin ratios. Patients with H. pylori eradication therapy were more often detected with functional ID compared to patients without eradication therapy, when using the new biomarkers.

Hepcidin correlates with interleukin-1β and interleukin-6 but not iron deficiency in children with Helicobacter pylori infection

BACKGROUND

Helicobacter pylori infection is associated with iron deficiency (ID) in children. Inflammatory cytokine reactions could influence the consequences of H. pylori infection. Hepcidin is an important regulator in iron homeostasis and could be induced by chronic inflammation. The relationship between hepcidin and cytokine levels in children infected with H. pylori remains controversial.

METHODS

Based on serology testing for anti-H. pylori IgG, participants (43 seropositive and 43 seronegative) aged 10-18 years were enrolled. Serum hepcidin levels and iron profiles, including iron, ferritin, and total iron-binding capacity, were measured. ID is defined as iron saturation less than 15%. Seropositive children were divided into low hepcidin (n = 22) and high hepcidin (n = 21) groups. IL-1β, IL-6, and IL-8 serum levels were compared.

RESULTS

Serum IL-1β and IL-6 levels were comparable between H. pylori seropositive and seronegative children, as were the median serum hepcidin levels (6.5 ng/mL versus 8.6 ng/mL; P = 0.1318). Median levels of serum iron, ferritin, and iron saturation were significantly lower in seropositive children with low hepcidin than in those with high hepcidin (P = 0.0123, P = 0.0001, and P = 0.0004, respectively). The prevalence of ID was significantly higher in those with low serum hepcidin levels (33.3% versus 4.5%; P = 0.015). Compared to the high hepcidin seropositive group, the low hepcidin group had significantly lower median serum levels of cytokines IL-1β and IL-6, but not IL-8 (P = 0.0151 and P = 0.0015, respectively).

CONCLUSIONS

Inflammatory cytokines IL-1β and IL-6, but not IL-8, might be associated with increased hepcidin levels among H. pylori-seropositive children. Further studies are needed to clarify the role of hepcidin.

Anemia and iron deficiency in gastrointestinal and liver conditions

Iron deficiency anemia (IDA) is associated with a number of pathological gastrointestinal conditions other than inflammatory bowel disease, and also with liver disorders. Different factors such as chronic bleeding, malabsorption and inflammation may contribute to IDA. Although patients with symptoms of anemia are frequently referred to gastroenterologists, the approach to diagnosis and selection of treatment as well as follow-up measures is not standardized and suboptimal. Iron deficiency, even without anemia, can substantially impact physical and cognitive function and reduce quality of life. Therefore, regular iron status assessment and awareness of the clinical consequences of impaired iron status are critical. While the range of options for treatment of IDA is increasing due to the availability of effective and well-tolerated parenteral iron preparations, a comprehensive overview of IDA and its therapy in patients with gastrointestinal conditions is currently lacking. Furthermore, definitions and assessment of iron status lack harmonization and there is a paucity of expert guidelines on this topic. This review summarizes current thinking concerning IDA as a common co-morbidity in specific gastrointestinal and liver disorders, and thus encourages a more unified treatment approach to anemia and iron deficiency, while offering gastroenterologists guidance on treatment options for IDA in everyday clinical practice.

Helicobacter pylori in children

Helicobacter pylori infection in early childhood may differ in many aspects compared to infection in adulthood: the immune response in the gut, the type and prevalence of complications within and outside the stomach, and the impact on long-term health. In high prevalence countries, transient infections seem to be common in infants and toddlers, and the consequences of this phenomenon on the short- and long-term immune response are still unclear. Other controversial issues are related to the question of which H. pylori-infected children benefit from treatment and which is the best regimen to eradicate the infection in the presence of a worldwide increasing antibiotic resistance. The first large-scale randomized placebo-controlled vaccination trial in schoolchildren indicates that prevention of the infection may be possible.

Helicobacter pylori and extragastric diseases

During the past year, many articles were published on the extragastric diseases related to Helicobacter pylori infection. This supports the theory that some microorganisms may cause diseases even far from the primary site of infection by interfering with different biologic processes. The role of H. pylori on idiopathic thrombocytopenic purpura, sideropenica anemia, and vitamin B12 deficiency is well known. On the other hand, there is a growing interest in the bacterium's association with cardiovascular, neurologic, hematologic, dermatologic, head and neck, and uro-gynecologic diseases, as well as diabetes mellitus and metabolic syndrome, with very promising results. This review has been aimed at summarizing the results of the most relevant studies published over the last year on this fascinating topic.

Helicobacter pylori Infection in Pediatrics

This review includes the main pediatric studies published from April 2014 to March 2015. The host response of Treg cells with increases in FOXP3 and TGF-β1 combined with a reduction in IFN-γ by Teff cells may contribute to Helicobacter pylori susceptibility in children. Genotypic variability in H. pylori strains influences the clinical manifestation of the infection. Helicobacter pylori infection is associated with variables indicative of a crowded environment and poor living conditions, while breast-feeding has a protective effect. Intrafamilial infection, especially from mother to children and from sibling to sibling, is the dominant transmission route. Studies showed conflicting results regarding the association between H. pylori infection and iron deficiency anemia. One study suggests that H. pylori eradication plays a role in the management of chronic immune thrombocytopenic purpura in H. pylori-infected children and adolescents. The prevalence of H. pylori was higher in chronic urticaria patients than in controls and, following H. pylori eradication, urticarial symptoms disappeared. An inverse relationship between H. pylori infection and allergic disease was reported. Antibiotic resistance and insufficient compliance to treatment limit the efficacy of eradication therapy. Sequential therapy had no advantage over standard triple therapy. In countries where H. pylori infection is prevalent, studies focusing on virulence factors and antibiotic susceptibility may provide anticipation of the prognosis and may be helpful to reduce morbidity and mortality.

Extragastric Diseases and Helicobacter pylori

The extragastric manifestations of Helicobacter pylori infection still remain a very strong topic throughout the H. pylori world. Indeed, H. pylori may interfere with many biological processes, both inside and outside of the stomach, possibly influencing or determining the occurrence of many diseases outside of the stomach. While its role in idiopathic thrombocytopenic purpura and sideropenic anemia has already been recognized, emerging evidence suggests that H. pylori may increase the risk of acute coronary syndrome, contribute to insulin resistance and be associated with neurodegenerative, respiratory, and other miscellaneous disorders previously associated with other conditions. Different pathogenic mechanisms have been hypothesized, including the induction of a low-grade inflammatory state and the occurrence of molecular mimicry mechanisms. This review summarizes the results of the most relevant studies published on this topic in the last year.