Proton Pump Inhibitors Reduce the Frequency of Phlebotomy in Patients With Hereditary Hemochromatosis

Crosstalk between Acidosis and Iron Metabolism: Data from In Vivo Studies

Iron absorption requires an acidic environment that is generated by the activity of the proton pump gastric H(+)/K(+)ATPase (ATP4), expressed in gastric parietal cells. However, hepcidin, the iron regulatory peptide that inhibits iron absorption, unexpectedly upregulates ATP4 and increases gastric acidity. Thus, a concept of link between acidosis and alterations in iron metabolism, needs to be explored. We investigated this aspect in-vivo using experimental models of NH4Cl-induced acidosis and of an iron-rich diet. Under acidosis, gastric ATP4 was augmented. Serum hepcidin was induced and its mRNA level was increased in the liver but not in the stomach, a tissue where hepcidin is also expressed. mRNA and protein levels of intestinal DMT1(Divalent Metal Transporter 1) and ferroportin were downregulated. Serum iron level and transferrin saturation remained unchanged, but serum ferritin was significantly increased. Under iron-rich diet, the protein expression of ATP4A was increased and serum, hepatic and gastric hepcidin were all induced. Taken together, these results provide evidence of in-vivo relationship between iron metabolism and acidosis. For clinical importance, we speculate that metabolic acidosis may contribute in part to the pathologic elevation of serum hepcidin levels seen in patients with chronic kidney disease. The regulation of ATP4 by iron metabolism may also be of interest for patients with hemochromatosis.

Proton pump inhibitors reduce phlebotomy burden in patients with HFE-related hemochromatosis: a systematic review and meta-analysis

BACKGROUND AND AIMS

Proton pump inhibitors (PPIs) may reduce iron absorption and serum ferritin levels in patients with homeostatic iron regulator (HFE)-related hemochromatosis, reducing the need for frequent phlebotomies. Our study aimed to perform for the first time a meta-analysis of existing observational and randomized controlled studies to ascertain the overall effect of PPI use in patients with HFE-related hemochromatosis.

METHODS

Studies in adults reporting the outcomes of PPIs use in hereditary hemochromatosis patients from Medline, Embase, Scopus and Google Scholar databases from inception to December 2019 were systematically searched. The study outcomes were the serum ferritin levels and annual requirement for phlebotomies. Pooled mean difference, and 95% confidence intervals (CIs) were obtained by the random-effects model. Forrest plots were constructed to show the summary pooled estimate. Heterogeneity was assessed by using I2 measure of inconsistency.

RESULTS

Following an initial search of 202 manuscripts, a total of three studies involving 68 patients with hemochromatosis (34 in the PPIs group and 34 in the placebo or non-PPI group) were included. A minimum duration of PPI use was 1 year. Patients who received PPIs therapy did not have a statistically significant lower serum ferritin levels (mean difference: -18.86, 95% CI: -60.44, 22.72, P = 0.37, I2 = 88%) but required significantly less sessions of phlebotomies annually (mean difference: -3.10, 95% CI: -4.46, -3.08, P < 0.00001, I2 = 93%). No publication bias was found on Egger (P = 0.94) or Begg (P = 0.98) tests.

CONCLUSION

PPIs can be used as an adjuvant therapy to reduce phlebotomy burden in patients with HFE-related hemochromatosis.

Absorption of nonheme iron during gastric acid suppression in patients with hereditary hemochromatosis and healthy controls

Phlebotomies are performed in hereditary hemochromatosis (HH) to maintain normal iron concentrations. Proton-pump inhibitors (PPIs) can reduce the number of phlebotomies in patients with HH. However, in patients without HH, the iron concentrations do not appear to be compromised when using PPIs. Therefore, we aim to explain the differences in iron absorption between patients with and without HH. In 10 p.cysteine282tyrosine (p.C282Y) homozygous HH patients with normalized iron stores and 10 healthy control subjects (HCs), the iron parameters and hepcidin concentrations were determined before ingestion of a pharmacological dose of 50 mg iron [ferric iron (Fe³⁺)] polymaltose and hourly for 4 h afterward. This was repeated after 7 days of treatment with pantoprazole 40 mg once daily. Serum iron concentrations and transferrin saturation percentages dropped significantly during PPI use in the patients with HH, whereas no changes were observed in the HCs. Hepcidin concentrations were lower in the patients with HH compared with the HCs both before and during PPI use. In both groups, hepcidin levels did not significantly decrease during the treatment. Seven-day PPI use significantly reduces iron absorption in patients with HH but not in HCs. Changes in hepcidin concentrations could not explain these different PPI effects on iron absorption probably due to a small sample size.NEW & NOTEWORTHY This study confirms that lowering gastric acidity by proton pump inhibitors results in a reduction in iron absorption in patients with hemochromatosis and not in healthy control subjects. The presupposition that a decrease in hepcidin concentration in healthy control subjects in response to lowering gastric acidity can explain the difference in iron absorption between these groups could not be confirmed probably because of a small sample size.

A Review of Nutrients and Compounds, Which Promote or Inhibit Intestinal Iron Absorption: Making a Platform for Dietary Measures That Can Reduce Iron Uptake in Patients with Genetic Haemochromatosis

Objective

To provide an overview of nutrients and compounds, which influence human intestinal iron absorption, thereby making a platform for elaboration of dietary recommendations that can reduce iron uptake in patients with genetic haemochromatosis.

Design

Review. Setting. A literature search in PubMed and Google Scholar of papers dealing with iron absorption.

Results

The most important promoters of iron absorption in foods are ascorbic acid, lactic acid (produced by fermentation), meat factors in animal meat, the presence of heme iron, and alcohol which stimulate iron uptake by inhibition of hepcidin expression. The most important inhibitors of iron uptake are phytic acid/phytates, polyphenols/tannins, proteins from soya beans, milk, eggs, and calcium. Oxalic acid/oxalate does not seem to influence iron uptake. Turmeric/curcumin may stimulate iron uptake through a decrease in hepcidin expression and inhibit uptake by complex formation with iron, but the net effect has not been clarified.

Conclusions

In haemochromatosis, iron absorption is enhanced due to a decreased expression of hepcidin. Dietary modifications that lower iron intake and decrease iron bioavailability may provide additional measures to reduce iron uptake from the foods. This could stimulate the patients' active cooperation in the treatment of their disorder and reduce the number of phlebotomies.

Adverse Effects of Proton Pump Inhibitors-Evidence and Plausibility

Proton pump inhibitors (PPIs) have been increasingly used over the last decades and there are concerns about overuse and the numerous reported side-effects. It is uncertain whether associations between PPI use and potential side effects are causal. However, important evidence from experimental and mechanistic studies that could support a causal relationship may have been underestimated by epidemiologists and meta-analysists. In the current manuscript we review the combined epidemiological and mechanistic evidence of the adverse effects of PPI use.

Diagnosis and Treatment of Genetic HFE-Hemochromatosis: The Danish Aspect

This paper outlines the Danish aspects of HFE-hemochromatosis, which is the most frequent genetic predisposition to iron overload in the five million ethnic Danes; more than 20,000 people are homozygous for the C282Y mutation and more than 500,000 people are compound heterozygous or heterozygous for the HFE-mutations. The disorder has a long preclinical stage with gradually increasing body iron overload and eventually 30% of men will develop clinically overt disease, presenting with symptoms of fatigue, arthralgias, reduced libido, erectile dysfunction, cardiac disease and diabetes. Subsequently the disease may progress into irreversible arthritis, liver cirrhosis, cardiomyopathy, pancreatic fibrosis and osteoporosis. The effective standard treatment is repeated phlebotomies, which in the preclinical and early clinical stages ensures a normal survival rate. Early detection of the genetic predisposition to the disorder is therefore important to reduce the overall burden of clinical disease. Population screening seems to be cost-effective and should be considered.

ACG Clinical Guideline: Hereditary Hemochromatosis

Hereditary hemochromatosis (HH) is one of the most common genetic disorders among persons of northern European descent. There have been recent advances in the diagnosis, management, and treatment of HH. The availability of molecular diagnostic testing for HH has made possible confirmation of the diagnosis for most patients. Several genotype-phenotype correlation studies have clarified the differences in clinical features between patients with the C282Y homozygous genotypes and other HFE mutation patterns. The increasing use of noninvasive tests such as MRI T2* has made quantification of hepatic iron deposition easier and eliminated the need for liver biopsy in most patients. Serum ferritin of <1,000 ng/mL at diagnosis remains an important diagnostic test to identify patients with a low risk of advanced hepatic fibrosis and should be used routinely as part of the initial diagnostic evaluation. Genetic testing for other types of HH is available but is expensive and generally not useful in most clinical settings. Serum ferritin may be elevated among patients with nonalcoholic fatty liver disease and in those with alcoholic liver disease. These diagnoses are more common than HH among patients with elevated serum ferritin who are not C282Y homozygotes or C282Y/H63D compound heterozygotes. A secondary cause for liver disease should be excluded among patients with suspected iron overload who are not C282Y homozygotes. Phlebotomy remains the mainstay of therapy, but emerging novel therapies such as new chelating agents may have a role for selected patients.

Use of proton pump inhibitors and risk of iron deficiency: a population-based case-control study

BACKGROUND

Hypochlorhydric states are an important cause of iron deficiency (ID). Nevertheless, the association between therapy with proton pump inhibitors (PPIs) and ID has long been a subject of debate. This case-control study aimed to investigate the risk of ID associated with the use of PPIs using the UK Clinical Practice Research Datalink (CPRD) database.

METHODS

Cases were patients aged 19 years or older with first-time diagnosis of ID between 2005 and 2016 (n = 26 806). The dates of first diagnosis of ID in cases defined the index dates. For each case, one control was matched by age, gender and general practice. A PPI "full" user (PFU) was defined as a subject who had received PPIs for a continuous duration of at least 1 year prior to the index date. A PPI "limited" users (PLU) was a subject who intermittently received PPI therapy. A PPI non-user (PNU) was a subject who received no PPI prescriptions prior to the index date. The odds ratio of ID in PFU and PLU compared to PNU was estimated using conditional logistic regression.

RESULTS

Among cases, 2960 were PFU, 6607 PLU and 17 239 PNU. Among controls, 1091 were PFU, 5058 PLU and 20 657 PNU. Adjusted odds ratio of ID in PFU and PLU compared to PNU was 3.60 (95%CI, [3.32-3.91]) and 1.51 (95% CI, [1.44-1.58]). Positive dose-response and time-response relationships were observed.

CONCLUSIONS

Chronic PPI use increases the risk of ID. Physicians should consider this when balancing the risks and benefits of chronic PPI prescription.

Proton Pump Inhibitors Decrease Phlebotomy Need in HFE Hemochromatosis: Double-Blind Randomized Placebo-Controlled Trial

Phlebotomy constitutes the established treatment for HFE-related hemochromatosis. Retrospective studies have suggested proton pump inhibitors (PPIs) reduce the need for phlebotomy in this population. We conducted a randomized controlled trial to prove this. Thirty p.C282Y homozygous patients were randomly allocated to PPI (pantoprazole 40 mg/day) or placebo for 12 months. Phlebotomies were performed when serum ferritin was > 100 μg/L. Phlebotomy need turned out to be significantly lower in patients taking PPI (P = .0052). PPI treatment significantly reduces the need for phlebotomies in p.C282Y homozygous patients. In view of the known long-term safety profile of PPI, they can be a valuable addition to standard therapy. Clinicaltrials.gov: NCT01524757.

Gastric acid secretion

PURPOSE OF REVIEW

The present review summarizes the past year's literature, both clinical and basic science, regarding neuroendocrine and intracellular regulation of gastric acid secretion and proper use of antisecretory medications.

RECENT FINDINGS

Gastric acid kills microorganisms, modulates the gut microbiome, assists in digestion of protein, and facilitates absorption of iron, calcium, and vitamin B12. The main stimulants of acid secretion are gastrin, released from antral G cells; histamine, released from oxyntic enterochromaffin-like cells; and acetylcholine, released from antral and oxyntic intramural neurons. Other stimulants include ghrelin, motilin, and hydrogen sulfide. The main inhibitor of acid secretion is somatostatin, released from oxyntic and antral D cells. Glucagon-like peptide-1 also inhibits acid secretion. Proton pump inhibitors (PPIs) reduce acid secretion and, as a result, decrease somatostatin and thus stimulate gastrin secretion. Although considered well tolerated drugs, concerns have been raised this past year regarding associations between PPI use and kidney disease, dementia, and myocardial infarction; the quality of evidence, however, is very low.

SUMMARY

Our understanding of the physiology of gastric secretion and proper use of PPIs continues to advance. Such knowledge is crucial for improved management of acid-peptic disorders.

How we manage patients with hereditary haemochromatosis

A number of disorders cause iron overload: some are of genetic origin, such as hereditary haemochromatosis, while others are acquired, for instance due to repeated transfusions. This article reviews the treatment options for hereditary haemochromatosis, with special attention to the use of erythrocytapheresis. In general, therapy is based on the removal of excess body iron, for which ferritin levels are used to monitor the effectiveness of treatment. For many decades phlebotomy has been widely accepted as the standard treatment. Recent publications suggest that erythrocytapheresis, as a more individualized treatment, can provide a good balance between effectiveness, tolerability and costs. Other treatments like oral chelators and proton pomp inhibitors, which are used in selected patients, create the possibility to further individualize treatment of hereditary haemochromatosis. In the future, hepcidin-targeted therapy could provide a more fundamental approach to treatment.

The modified iron avidity index: a promising phenotypic predictor in HFE-related haemochromatosis

OBJECTIVE

Phenotypes of the HFE-related haemochromatosis vary considerably, making it hard to predict the course of iron accumulation. The aim of this retrospective study was to determine if the Iron Avidity Index (IAI) is a good phenotypic predictor of the number of phlebotomies needed per year during maintenance treatment (NPDMT) in patients with homozygous p.C282Y hereditary haemochromatosis (HH).

METHODS

Patients with HH homozygous for p.C282Y, on maintenance treatment for at least 1 year were included. The IAI (ferritin level at diagnosis/age at diagnosis) was calculated.

RESULTS

Ninety-five patients were included in the analysis. Linear regression analysis showed the confounding effect of sex on the relationship between IAI and NPDMT. A modified IAI, adjusted for sex, was calculated. As proton pump inhibitor (PPI) use was independently associated with NPDMT, the group was split in PPI- and non-PPI-users. A positive correlation between the modified IAI and the NPDMT was shown in both groups (PPI r = 0.367, P = 0.023; non-PPI r = 0.453, P < 0.001). An ROC was computed to measure the accuracy of the modified IAI to predict who needed 0-2 vs. ≥3 maintenance treatments per year. The AUROC in the PPI and non-PPI group were respectively 0.576 (0.368-0.784) and 0.752 (0.606-0.899).

CONCLUSION

The modified IAI is a fairly good predictor in non-PPI-using homozygous C282Y HH patients, to differentiate who needs ≥3 maintenance phlebotomies per year. Therefore, this index might help to select patients that benefit from an alternative less frequent therapy, e.g. erythrocytapheresis.