Effects of iron supplements in individuals with erythropoietic protoporphyria

BACKGROUND

Protoporphyrin IX (PPIX) is the final precursor of heme, forming heme when iron is inserted. Individuals with erythropoietic protoporphyrias (EPP) have accumulation of PPIX, causing photosensitivity and increased liver disease risk. Many also have iron deficiency and anemia. We investigated outcomes of oral iron supplements in individuals with EPP.

METHODS

A systematic review identified literature on oral iron supplements in EPP patients. Subsequently, we administered iron supplements to EPP patients with iron deficiency. The primary outcome was impact on PPIX level. Secondary outcomes were adverse events and relative differences in hemoglobin and iron parameters.

RESULTS

The systematic review found 13 case reports and one uncontrolled clinical trial with uncertain results. From our department 10 patients with EPP and iron deficiency took daily dosages of 330 mg of ferrous fumarate for two months. Five of our patients had anemia at baseline. After 2 months of supplementation seven patients had increased PPIX level compared to baseline, two had decrease, one remained unchanged. The administration of iron led to a rise in ferritin, and in four of the anemic patients also to an improvement in blood hemoglobin. A small transiently elevation in plasma alanine transaminase concentration was observed during supplementation.

CONCLUSIONS

Overall, iron supplementation in EPP patients replenished iron stores and elevated erythrocyte PPIX and plasma alanine transaminase. For anemic patients, there was some degree of normalization of the hemoglobin level. If iron therapy is needed for EPP patients, monitoring of photosensitivity, PPIX, hemoglobin, and plasma liver enzymes is advisable.

Development and content validation of a sunlight exposure diary in patients with erythropoietic protoporphyria

BACKGROUND

Erythropoietic protoporphyria is a rare, inherited disorder presenting in early childhood with severe, painful phototoxicity. EPP has significant impacts on health-related quality of life, though there is variable disease severity. Accurately capturing how much time individuals with EPP can spend outdoors before they develop symptoms is critical to understanding HRQoL and measuring therapeutic response. Therefore, the goal of this study was to develop a comprehensive and content valid sun exposure diary to assess the efficacy of new therapies in individuals with EPP.

METHODS

Qualitative interviews were conducted with adult and adolescent EPP participants, as well as five clinical experts, to obtain their input on the content of an existing sun exposure diary. Revisions to the diary were made based on evidence generated in cognitive debriefing interviews analyzed in eight consecutive groups of EPP participant.

RESULTS

Interviews were conducted with 17 adults and 6 adolescents with EPP. The average age of adults was 40 years and of adolescents was 14 years. Clinical experts thought the original diary needed clarification on the description of symptoms, how time outdoors was captured, and the distinction between direct vs. indirect sunlight. Participants with EPP also noted these items needed revision, and that the distinction between prodromal symptoms and full reaction symptoms should be clarified. In the final diary version, participants with EPP found most items to be clear and easy to complete/think about. Seventy-six percent of participants (13/17) asked thought the diary was easy to complete. The remainder thought the majority of the diary was easy to complete with the exception of select questions.

CONCLUSIONS

Evaluating a new treatment for EPP requires accurately capturing time in sunlight and symptoms in this unique disorder. The newly developed sun exposure diary is content valid and can be used to assess important aspects of symptoms and daily life and therefore evaluate clinically meaningful therapeutic response.

Protoporphyrin IX-induced phototoxicity: Mechanisms and therapeutics

Protoporphyrin IX (PPIX) is an intermediate in the heme biosynthesis pathway. Abnormal accumulation of PPIX due to certain pathological conditions such as erythropoietic protoporphyria and X-linked protoporphyria causes painful phototoxic reactions of the skin, which can significantly impact daily life. Endothelial cells in the skin have been proposed as the primary target for PPIX-induced phototoxicity through light-triggered generation of reactive oxygen species. Current approaches for the management of PPIX-induced phototoxicity include opaque clothing, sunscreens, phototherapy, blood therapy, antioxidants, bone marrow transplantation, and drugs that increase skin pigmentation. In this review, we discuss the present understanding of PPIX-induced phototoxicity including PPIX production and disposition, conditions that lead to PPIX accumulation, symptoms and individual differences, mechanisms, and therapeutics.

Afamelanotide Is Associated with Dose-Dependent Protective Effect from Liver Damage Related to Erythropoietic Protoporphyria

In animal models, melanocyte-stimulating hormones (MSHs) protect the liver from various injuries. Erythropoietic protoporphyria (EPP), a metabolic disorder, leads to the accumulation of protoporphyrin (PPIX). In addition to the most prominent symptom of incapacitating phototoxic skin reactions, 20% of EPP patients exhibit disturbed liver functioning and 4% experience terminal liver failure caused by the hepatobiliary elimination of excess PPIX. Skin symptoms are mitigated through the application of the controlled-release implant afamelanotide, an α-MSH analog, every sixty days. Recently, we showed that liver function tests (LFTs) improved during afamelanotide treatment when compared to before treatment. The present study investigated whether this effect is dose-dependent, as the evidence of dose dependency would support a beneficial influence of afamelanotide.

METHODS

In this retrospective observational study, we included 2933 liver-function tests, 1186 PPIX concentrations and 1659 afamelanotide implant applications in 70 EPP patients. We investigated whether the number of days since the preceding afamelanotide dose or the number of doses during the preceding 365 days had an effect on LFTs and PPIX levels. In addition, we assessed the effect of global radiation.

RESULTS

Inter-patient differences exerted the most prominent effect on PPIX and LFTs. In addition, PPIX increased significantly with an increase in the number of days since the last afamelanotide implant (p < 0.0001). ALAT and bilirubin decreased significantly with an increasing number of afamelanotide doses in the preceding 365 days (p = 0.012, p = 0.0299, respectively). Global radiation only influenced PPIX (p = 0.0113).

CONCLUSIONS

These findings suggest that afamelanotide ameliorates both PPIX concentrations and LFTs in EPP in a dose-dependent manner.

Results from a first-in-human study of dersimelagon, an investigational oral selective MC1R agonist

PURPOSE

To describe outcomes from the first-in-human study of dersimelagon, an investigational oral selective MC1R agonist, under development for the treatment of erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP).

METHODS

In this double-blind, placebo-controlled phase 1 study, the safety, tolerability, pharmacokinetics, and pharmacodynamics of single and multiple ascending oral doses of dersimelagon in healthy participants were evaluated.

RESULTS

Dersimelagon was generally well tolerated in healthy participants, with the most common TEAEs being lentigo (52.8%) and skin hyperpigmentation (50.0%) after multiple doses. Systemic exposure to dersimelagon in plasma (based on AUC_0-∞ and C_max) increased in a slightly more than dose-proportional manner over the 1- to 600-mg single-dose range. Following multiple doses, dersimelagon was rapidly absorbed (median T_max ranging from 4 to 5 h postdose on days 1 and 14). Mean t_1/2 ranged from 10.56 to 18.97 h on day 14, and the steady state of plasma concentration was generally reached by 5 days of multiple dosing. There were no observable effects of age or race on the PK profile of dersimelagon or its metabolite dersimelagon glucuronide. No treatment-related effects on melanin density (MD) were observed following single doses of dersimelagon; however, after multiple doses, increases in MD were observed in participants receiving 150 and 300 mg dersimelagon.

CONCLUSION

Our study results indicate that dersimelagon is generally well tolerated and demonstrates a generally consistent PK profile across diverse subgroups. Treatment-related increases in MD warrant further investigation in a larger study population and in patients with EPP and XLP.

TRIAL REGISTRATION

A Study to Investigate the Safety, Tolerability and Pharmacokinetics of MT-7117 in Healthy Subjects, NCT02834442, https://clinicaltrials.gov/ct2/show/NCT02834442 , registration began July 2016.

Experimental and approved treatments for skin photosensitivity in individuals with erythropoietic protoporphyria or X-linked protoporphyria: A systematic review

Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are characterized by skin photosensitivity caused by accumulation of protoporphyrin IX. We aimed to review the clinical evidence of efficacy and safety of skin photosensitivity treatments in individuals with EPP or XLP. We systematically searched MEDLINE, Embase, the Cochrane Library, and ClinicalTrials.gov. A total of 40 studies with data on 18 treatment modalities were included. Comprehensive treatment safety data were obtained from the European Medicines Agency and the United States Food and Drug Administration. The studies used different outcome measures to evaluate the sensitivity without a generally accepted method to assess treatment effect on skin photosensitivity. Of the included studies, 13 were controlled trials. Gathered, the trials showed moderate positive effect of inorganic sunscreen application and subcutaneous implant of afamelanotide and no effect of organic sunscreen application, or oral treatment with beta-carotene, cysteine, N-acetylcysteine, vitamin C, or warfarin. Studies without control groups suggested treatment effect of foundation cream, dihydroxyacetone/lawsone cream, narrow-band ultraviolet B phototherapy, erythrocyte transfusion, extracorporeal erythrocyte photodynamic therapy, or oral treatment with zinc sulphate, terfenadine, cimetidine, or canthaxanthin, but the real effect is uncertain. Assessment of treatment effect on photosensitivity in patients with EPP or XLP carries a high risk of bias since experienced photosensitivity varies with both weather conditions, exposure pattern, and pigmentation. Controlled trials of promising treatment options are important although challenging in this small patient population.

Protection against visible light by dihydroxyacetone in erythropoietic protoporphyria

BACKGROUND

Patients with erythropoietic protoporphyria (EPP) are hypersensitive to long wave ultraviolet (UVA) radiation and visible light and they experience severe skin pain by light exposure. The patients have very limited treatment options. Sunless skin tanning with dihydroxyacetone (DHA) is now being investigated as a possible treatment modality of skin photosensitivity in EPP.

METHODS

We simulated the theoretical light protection factor provided by DHA application. In addition, we present 19 cases with EPP who were treated at our department with DHA weekly during spring and summer from 2018 to 2021 inclusive.

RESULTS

The protection factor against UVA and visible light was estimated to approximately two. Out of the 19 patients with EPP who were treated with DHA in 2018, 11 patients experienced a sustained good effect and continued to use the treatment on a weekly basis in the spring and summer of 2019, 2020, and 2021.

CONCLUSION AND PERSPECTIVES

Both the theoretical estimates and the uncontrolled study suggest that sunless tanning with DHA reduces photosensitivity in patients with EPP. Our hypothesis is that skin treated with DHA can tolerate twice the daylight dose compared to untreated skin before onset of skin symptoms. To validate this conclusion, we plan a randomized clinical trial to determine the effect of DHA application to reduce photosensitivity in patients with EPP under controlled clinical conditions. The study protocol for this trial is presented in the paper.

Cimetidine for erythropoietic protoporphyria

BACKGROUND

Erythropoietic protoporphyria (EPP) is caused by deficiency of the enzyme converting protoporphyrin IX (PpIX) into heme resulting in accumulation of PpIX leading to photosensitivity and liver toxicity. Cimetidine might inhibit δ-aminolevulinic acid synthase influencing the heme biosynthesis. We present cases with EPP treated with cimetidine at our department, and a literature review.

METHODS

Systematic searches were performed to identify literature describing EPP patients treated with cimetidine. On that ground we treated EPP patients with cimetidine through spring and summer in 2020 and 2021 at our department. Their erythrocyte PpIX level and standard blood and liver parameters were collected before and during 4 months of treatment. Using a questionnaire, patients were asked about change in photosensitivity, side effects, and whether they would like to resume treatment in the spring of 2022.

RESULTS

Literature searches identified 9 patients treated with cimetidine. Four were outpatients reporting decreased photosensitivity. At our department 18 outpatients started treatment. Fifteen used oral cimetidine daily for 4 months or more providing a significant decrease in erythrocyte PpIX with a median of 20% (range: -18% to 53%) after 4 months. Eleven of the 15 patients reported a decrease in photosensitivity during treatment, 3 patients were unsure, and 1 patient experienced unchanged photosensitivity. Only mild side effects were reported. Fourteen patients requested to resume treatment in the spring of 2022.

CONCLUSIONS

These cases suggest that cimetidine can lower erythrocyte PpIX in patients with EPP.

Liver involvement in patients with erythropoietic protoporphyria: retrospective analysis of clinicopathological features of 5 cases

Erythropoietic protoporphyria (EPP) is a rare inherited disease whose morbidity is about 1:75,000 to 1:200,000. It is caused by the deficiency of porphyrin ferrochelatase (FECH). Liver involvement in EPP is even rarer. The diagnosis of EPP with liver involvement mainly relies on clinical manifestations, laboratory examinations, histopathological examinations and genetic testing, which is still a huge challenge for both clinicians and pathologists. Here, 5 cases of EPP with liver injury were collected, and the clinicopathological features of these patients were analyzed. The clinical manifestations and laboratory examinations varied from person to person, whereas the liver biopsies showed that there were dark brown deposits within the hepatocytes, Kupffer cells, bile canaliculi and the lumen of bile ducts, which was a constant finding by histopathological examination. Gene tests were conducted in two of the five cases, and the results confirmed the diagnosis. Fully understanding of the diseases can help us reduce the rate of missed diagnosis and provide proper treatment as early as possible.

Distribution of protoporphyrin IX in erythrocytes in a case of acquired erythropoietic protoporphyria

BACKGROUND

Erythropoietic protoporphyria (EPP) is a rare genetic photodermatosis caused by loss-of-function mutations in the gene for ferrochelatase leading to accumulation of the fluorescent protoporphyrin IX (PpIX) in erythrocytes. The mutations are most often inherited mutations present in all cells causing inherited EPP. In very rare cases EPP are acquired in association with myelodysplastic syndromes or myeloproliferative neoplasms, conditions with genetic instability.

CASE REPORT

We report a case of acquired EPP in association with hematological disease. We followed erythrocyte PpIX concentration over a year and measured PpIX fluorescence in individual erythrocytes in a blood sample from the case using flow cytometry. The major proportion of erythrocytes did not fluoresce (84%), whereas 13% contained low PpIX fluorescence, 1% contained medium fluorescence, and 2% contained high fluorescence.

DISCUSSION

Our observation of the very skewed PpIX distribution in erythrocytes supports the description that acquired EPP is caused by a somatic mutation affecting a clone of hematopoietic cells.

The effect of vitamin D recommendations on serum 25-hydroxyvitamin D level in patients with erythropoietic protoporphyria

OBJECTIVES

Patients with erythropoietic protoporphyria (EPP) avoid sun exposure owing to photosensitivity. For decades, sun-avoiding Danes have been recommended daily vitamin D supplements all year. We offered our EPP patients serum 25-hydroxyvitamin D (25(OH)D) monitoring, and counseling if their level was low. We aimed to investigate the effect of the general recommendation and counseling on 25(OH)D status in patients attending our clinic. Additionally, the 25(OH)D status of our EPP patients was compared to that of British patients with EPP not taking vitamin D supplements and with that of the general Danish population.

METHODS

Forty-six Danish patients with EPP had 25(OH)D measured in 721 blood samples collected between 2003 and 2021. Dates of individual counseling were noted. Data on British patients with EPP and the general Danish population were extracted from previous publications.

RESULTS

Our patients had higher 25(OH)D levels than British patients with EPP not taking vitamin D supplements, but the recommendations did not elevate their 25(OH)D levels to that of the general Danish population. Overall, 17.5% of the 25(OH)D measurements in our EPP patients were below 30 nmol/L (deficiency) and 29.4% were between 30 and 50 nmol/L (insufficiency). Patients were monitored for a median of 11 y. Thirty-one patients had a total of 74 vitamin D counseling sessions, providing an increase in 25(OH)D of about 18 nmol/L the year after. However, many patients repeatedly developed insufficiency.

CONCLUSIONS

This study documents the positive effect of vitamin D recommendations on serum 25(OH)D in patients with EPP. Follow-up on vitamin D status and recommendations is essential to increase 25(OH)D levels.

Validation of a novel patient reported tool to assess the impact of treatment in erythropoietic protoporphyria: the EPP-QoL

BACKGROUND

A novel treatment has been developed for erythropoietic protoporphyria (EPP) (a rare condition that leaves patients highly sensitive to light). To fully understand the burden of EPP and the benefit of treatment, a novel patient reported outcome (PRO) measure was developed called the EPP-QoL. This report describes work to support the validation of this measure.

METHODS

Secondary analysis of trial data was undertaken. These analyses explored the underlying factor structure of the measure. This supported the deletion of some items. Further work then explored the reliability of these factors, their construct validity and estimates of meaningful change.

RESULTS

The factor analyses indicated that the items could be summarised in terms of two factors. One of these was labelled EPP Symptoms and the other EPP Wellbeing, based on the items included in the domain. EPP Symptoms had evidence to support its reliability and validity. EPP Wellbeing had poor psychometric properties.

CONCLUSIONS

Based on the analysis it was recommended to drop the EPP Wellbeing domain (and associated items). EPP Symptoms, despite limitations in the development of items, showed evidence of validity. This work is consistent with the recommendations of a task force that provided recommendations regarding the development, modification and use of PROs in rare diseases.

[Phototherapy in the "City of Light" Jena]

In 1801, ultraviolet (UV) radiation was first described in Jena (Germany). Over the course of the last 200 years, the city has developed into a university and industry center for glass production, optics and spectroscopy. How this development influenced dermatotherapy in Jena is the subject of this article. In the late 19th century, the developing glass and optic industry of Jena played a leading role in the production of electric lamps for therapeutic use. Although production in Jena did not become established for dermatotherapeutic lamps, Jena glassmakers remained a supplier of UV filters. The industry's fortunes were generously spent on development of the city and university and enabled the creation of a dermatology clinic in an independent building. A department of radio- and phototherapy was established and since then has been part of the dermatology clinic's therapeutic portfolio. Although the city of Jena faced heavy economic repression, the industry and the dermatology clinic's scientific activity expanded to fluorescence and protein diagnostics in the early 1960s. Investigations by Professor Heinz Langhof led to the description of erythropoietic protoporphyria (EPP) simultaneously, but independently from English colleagues, whose publication is considered EPP's first description. The first functioning laser in the former German Democratic Republic was built at the university, although the first laser beam was created by a research group in Berlin a short time before. Use of laser technology in the dermatology department proceeded only after political changes began. Despite economic hardships, excellent research was done in Jena through intense collaborations. The dermatology clinic has thus been able to offer modern phototherapy from the very beginning.

Afamelanotide for prevention of phototoxicity in erythropoietic protoporphyria

Introduction: In erythropoietic protoporphyria (EPP), an inherited disorder of heme biosynthesis, accumulation of protoporphyrin IX results in acute phototoxicity. EPP patients experience severe burning pain after light exposure, which results in a markedly reduced quality of life. Afamelanotide is the first effective approved medical treatment for EPP, acting on melanocortin-1 receptors. This article aims to review afamelanotide.Areas covered: This review summarizes the chemical properties, pharmacokinetics, safety, preclinical and clinical data on afamelanotide in EPP, and post-marketing surveillance. PubMed search, manufacturers' websites, and relevant articles used for approval by authorities were used for the literature search.Expert opinion: Afamelanotide is an α-melanocyte-stimulating hormone analog. It can activate eumelanogenesis without exposure to UV radiation. Clinical studies in EPP showed that afamelanotide treatment significantly increased exposure to sunlight and QoL. In our clinical experience afamelanotide treatment is much more effective in clinical practice than demonstrated in clinical trials and should be made available for all EPP patients meeting inclusion criteria. The 60-day interval period was not based on effectiveness studies, and therefore for some of the patients the maximum of four implants per year with the 60-day interval is insufficient. Afamelanotide is well tolerated; common adverse events were headache, fatigue, and nausea.

Light-provoked skin symptoms on the hands of erythropoietic protoporphyria patients related to personal dosimeter measurements, skin symptoms, light protection and priming

Erythropoietic protoporphyria (EPP) is characterised by accumulation of protoporphyrin IX (PpIX) in erythrocytes. Upon illumination PpIX is released to the skin. Activation of the photoactive substance PpIX causes painful skin symptoms. This study aimed to objectively quantify individual light exposure of EPP patients in their everyday lives through spring and summer. We further aimed to establish the associations between daily symptoms and light exposure dose to photoprimed and non-photoprimed skin, use of gloves, and erythrocyte PpIX concentration. 14 Danish EPP patients participated from April through June, the period when symptoms are most frequent. Light exposure was measured using personal electronic dosimeters with sensor sensitivity comparable to the absorption spectrum of PpIX, measuring the biological effect of the light in this disease. Concurrently participants reported symptoms and use of protective gloves in a diary. Patients had a blood sample analysed for erythrocyte PpIX. The median patient was exposed to an average daily PpIX-weighted light dose of 3.8 J/cm² corresponding to approximately 15 min in the midday sun during summer in Denmark. The median patient reported symptoms on 29% and wore gloves on 11% of study days. There was a significant positive correlation between erythrocyte PpIX concentration and percentage of days wearing gloves (r = 0.65, p = 0.011), and a significant negative correlation between erythrocyte PpIX concentration and mean daily light dose on days not wearing gloves (r = -0.53, p = 0.049). Photosensitivity was strongly dependent on photopriming.

Increased phototoxic burn tolerance time and quality of life in patients with erythropoietic protoporphyria treated with afamelanotide - a three years observational study

BACKGROUND

Erythropoietic protoporphyria (EPP) is an ultra-rare genetic disorder (prevalence 1:150`000) characterized by instant painful phototoxic burn reactions in skin exposed to visible light. Afamelanotide is the first clinically tested therapy effectively increasing the time EPP patients can spend in direct sunlight without developing symptoms and reducing the number and severity of phototoxic reactions.

OBJECTIVES

We report our data on real-world effectiveness of afamelanotide treatment in EPP and its phototoxic burn protection factor (PBPF).

METHODS

We analysed clinical data collected between 2016 and 2018 in the Swiss EPP cohort (n = 39) on maximum phototoxic burn tolerance time (PBTT), i.e., maximum time spent in sunlight without phototoxic reaction, severity of phototoxic reactions as assessed by an 11-point Likert-type visual analogue scale (VAS), with 0 being no pain and 10 being the worst possible pain, and Quality of Life (QoL), as assessed with an EPP-specific instrument.

RESULTS

Before treatment, the PBTT was median 10 min (IQR 5-20). Under treatment, PBTT increased to median 180 min (IQR 120-240). Individual PBPF increased 1.8- to 180-fold (full range, median 15). The pain severity of the worst phototoxic reaction before treatment was median 10 and under treatment median 6 (IQR 3-7). QoL at the end of the observation period in 2018 (with all the assessed patients under treatment) was 81.4% (IQR 69.4-93.4, n = 34). A 97.4% treatment adherence rate was observed.

CONCLUSION

Treatment of EPP patients with afamelanotide is highly effective under real-world conditions. We suggest PBTT as a clinical meaningful endpoint in further clinical trials.

Trends in erythrocyte protoporphyrin IX concentration by age, sex and season among patients with erythropoietic protoporphyria-20 years of follow-up

BACKGROUND

Erythropoietic protoporphyria (EPP) is an inherited disorder leading to an increased concentration of the photoactive protoporphyrin IX (PpIX) in erythrocytes. Upon photoactivation in the dermal blood vessels and release to the skin, it causes painful skin symptoms when illuminated, depending on PpIX concentration. The present study aimed to investigate if erythrocyte PpIX concentration changes with age in patients with EPP. In addition, we tested gender differences and seasonal variation in erythrocyte PpIX concentration.

METHODS

53 EPP patients aged 0-90 years were included in this retrospective observational study. A total of 751 blood samples were routinely analyzed for erythrocyte PpIX between 2000 and 2020. Trends in erythrocyte protoporphyrin IX concentration depending on age, sex and season were investigated.

RESULTS

Erythrocyte PpIX levels increased during childhood and youth (median annual increase of 2.7 μmol/L) to reach a stable level in adults though, with a decrease in concentration of about 8% in summer. On average the PpIX level was higher in men (mean of 56 μmol/L, range: 6-139) than women (mean of 38 μmol/L, range: 6-82).

CONCLUSION

We hope that our results can contribute to finding a physiological explanation for the changes in erythrocyte PpIX observed throughout the lives of patients with EPP.

Inactivation of protoporphyrin IX in erythrocytes in patients with erythropoietic protoporphyria: A new treatment modality

BACKGROUND

Erythropoietic protoporphyria (EPP) is a rare, genetic disease with reduced ferrochelatase activity causing protoporphyrine IX (PpIX) to accumulate in erythrocytes. PpIX activation by daylight causes skin erythema, edema, burning, and stinging. No treatment exists to reduce PpIX.

AIM

To introduce a method that reduces PpIX in erythrocytes to relieve skin symptoms in patients with EPP.

METHOD

A case series of 7 patients with EPP constituted this explorative study. Erythrocyte PpIX was inactivated by illuminating the patients' heparinized blood outside their body, then returning it to the patient. About 3 litres of blood was illuminated with 630 nm light, 20 J/cm². The effect was measured as a reduction in erythrocyte PpIX. The patients reported the number of minutes in daylight tolerated before and after intervention.

RESULTS

This procedure reduced PpIX by about 30 % and daylight tolerance was, on average, increased by 14 times. The subsequently excreted photoproducts resulted in some liver toxicity. Three treatments during spring and early summer were sufficient to reduce the patients' symptoms throughout the year in Northern Europe.

CONCLUSION

Extracorporeal erythrocyte photodynamic therapy is the first treatment to successfully reduce the amount of PpIX in the blood of EPP patients, thus "normalizing" their daylight tolerance.

Psychosocial issues in erythropoietic protoporphyria - the perspective of parents, children, and young adults: A qualitative study

Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are rare photodermatoses, generally presenting in childhood with severe and painful phototoxicity. EPP has been reported to negatively affect quality of life (QoL), but there is limited information on the psychosocial issues faced by patients and families. To address this, an online focus group study was conducted to explore the perspective of parents of children with EPP, and young adults and children with EPP. Five focus groups were conducted in a semi-structured format, with moderator-led discussions exploring the impact on QoL. Three focus groups included parents of children with EPP, one with children aged 10-11 years, and another with young adults aged 24-25 years, for a total of 24 participants. Thematic data analysis showed that parents experience guilt for being unable to protect their children and frustration with the current state of knowledge of EPP. Parents also admitted that the disease can lead to stress within family members which is difficult to manage. Young adults expressed embarrassment over having to explain the disease to others. They reported that the teenage years were the most difficult to navigate; however, they learned to adapt to their disease as they grew older. Children expressed that they had limited understanding of their disease and wished they were told what symptoms to expect by physicians earlier in life. Our findings emphasize the significant impact on QoL for these families and a lack of age appropriate information for children with EPP. These findings can help improve counseling and support resources for patients and caregivers.

Letter to the editor: Diagnosis of erythropoietic protoporphyria with severe liver injury - a case report

Erythropoietic protoporphyria (EPP) is an extremely rare disease which is often unrecognized as diagnosis. In the recent article Lui et al describe a patient with a new diagnosis of EPP with severe liver injury. Approximately 5%-20% of patients with EPP develop liver manifestations. The most severe complication of EPP is an hepatic crisis, which is a medical emergency requiring urgent treatment. Intensive treatment should consist of (exchange) transfusions and preferably in a center that performs liver transplantations.

Characterization of a novel pathogenic variant in the FECH gene associated with erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is an autosomal recessive deficiency in heme biosynthesis due to pathogenic variants in the ferrochelatase gene (FECH). Patients present with lifelong photosensitivity and potential liver disease. Here we report a novel FECH variant designated c.904_912+1del found in trans with the c.315-48T>C hypomorphic variant, in one family with three affected individuals. These patients presented with immediate painful cutaneous photosensitivity but no hepatic manifestations. All have elevated protoporphyrin levels consistent with a diagnosis of EPP. Genetic, biochemical, and functional assay results obtained for this family suggest that the unique variant c.904_912+1del is likely pathogenic and thus causative of EPP.

Perioperative management of a bleeding jejunal tumor in a patient with erythropoietic protoporphyria: A case report and literature review

Introduction

Erythropoietic protoporphyria (EPP) is a rare disorder caused by reduced ferrochelatase activity and shows incomplete autosomal dominant inheritance. Meticulous perioperative management can avoid characteristic complications. This report describes a case of a bleeding jejunal tumor in a patient with EPP.

Presentation of case

A 49-year-old man with a history of EPP was admitted to our department with abdominal distention and severe anemia. Contrast-enhanced computed tomography revealed an abdominal tumor measuring 5 cm, originating from the small bowel wall or mesentery. Tumor resection was planned after correction of anemia. Red blood cell transfusion restored his hemoglobin to acceptable levels; however, his liver function worsened. Institution of liver support therapy achieved gradual reduction in his elevated liver enzymes; however, hyperbilirubinemia persisted. He underwent tumor resection on the 12^th day of hospitalization. Yellow filters were used to avoid operating room light-induced tissue injury. The tumor was located in the jejunum 30 cm from the Treitz ligament toward the anal aspect. The histopathological diagnosis was desmoid-type fibromatosis of the jejunum. Postoperatively, his hemoglobin levels were stabilized; however, his serum bilirubin level remained high. His serum bilirubin level gradually decreased following hemin injections (150 mg/day).

Discussion

Reducing heme synthesis and minimizing protoporphyrin generation are important perioperatively. Additionally, preventing operating room light-induced tissue burns and selecting appropriate anesthestic agents are important during surgery.

Conclusion

The institution of appropriate treatment and adequate intra- and perioperative measures can ensure safe surgery in patients with EPP even under emergency conditions.

[The cutaneous porphyrias]

The porphyrias are a group of metabolic disorders resulting from an innate abnormality in haem biosynthesis, and the clinical settings of which vary according to the genetic enzyme abnormality in question. These are genetic disorders with autosomal dominant or recessive inheritance of varying penetrance, and whose clinical expression differs according to the preferential location of haem precursors. Different classifications have been proposed according to genetic inheritance, the enzyme anomaly at issue, and clinical expression. The clinical classification distinguishes between acute porphyria (acute intermittent porphyria, porphyria variegata, hereditary coproporphyria), bullous cutaneous porphyrias (porphyria cutanea tarda, porphyria variegata and hereditary coproporphyria), painful photosensitive acute cutaneous porphyrias (erythropoietic protoporphyria and X-linked dominant protoporphyria), and rare recessive porphyrias (congenital erythropoietic porphyria, Doss porphyria, hepatoerythropoietic porphyria and harderoporphyria). Treatment depends on the clinical expression of the disorder.

Porphyrias and photosensitivity: pathophysiology for the clinician

Porphyrias are disorders caused by defects in the biosynthetic pathway of heme. Their manifestations can be divided into three distinct syndromes, each attributable to the accumulation of three distinct classes of molecules. The acute neurovisceral syndrome is caused by the accumulation of the neurotoxic porphyrin precursors, delta aminolevulinic acid, and porphobilinogen; the syndrome of immediate painful photosensitivity is caused by the lipid-soluble protoporphyrin IX and, the syndrome of delayed blistering photosensitivity, caused by the water-soluble porphyrins, uroporphyrin, and coproporphyrin. Porphyrias can manifest with one, or with a combination, of these syndromes, depending on whether one or more types of molecules are being accumulated. Iron plays a significant role in some of these conditions, as evidenced by improvements in both clinical manifestations and laboratory parameters, following iron depletion in porphyria cutanea tarda, or iron administration in some cases of X-linked erythropoietic protoporphyria. While the pathophysiology of a specific type of porphyrias, the protoporphyrias, appears to favor the administration of zinc, results so far have been conflicting, necessitating further studies in order to assess its potential benefit. The pathways involved in each disease, as well as insights into their pathobiological processes are presented, with an emphasis on the development of photosensitivity reactions.

Liver metabolomics in a mouse model of erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is a genetic disease that results from the defective mutation in the gene encoding ferrochelatase (FECH), the enzyme that converts protoporphyrin IX (PPIX) to heme. Liver injury and even liver failure can occur in EPP patients because of PPIX accumulation in the liver. The current study profiled the liver metabolome in an EPP mouse model caused by a Fech mutation (Fech-mut). As expected, we observed the accumulation of PPIX in the liver of Fech-mut mice. In addition, our metabolomic analysis revealed the accumulation of bile acids and ceramide (Cer) in the liver of Fech-mut mice. High levels of bile acids and Cer are toxic to the liver. Furthermore, we found that the major phosphatidylcholines (PC) in the liver and the ratio of total PC to PPIX in the bile were decreased in Fech-mut mice compared to wild type mice. A decrease of the ratio of PC to PPIX in the bile can potentiate the accumulation of PPIX in the liver because PC increases PPIX solubility and excretion. These metabolomic findings suggest that the accumulation of PPIX, together with the disruption of the homeostasis of bile acids, Cer, and PC, contributes to EPP-associated liver injury.

The role of ClpX in erythropoietic protoporphyria

Hemoglobin is an essential biological component of human physiology and its production in red blood cells relies upon proper biosynthesis of heme and globin protein. Disruption in the synthesis of these precursors accounts for a number of human blood disorders found in patients. Mutations in genes encoding heme biosynthesis enzymes are associated with a broad class of metabolic disorders called porphyrias. In particular, one subtype - erythropoietic protoporphyria - is caused by the accumulation of protoporphyrin IX. Erythropoietic protoporphyria patients suffer from photosensitivity and a higher risk of liver failure, which is the principle cause of morbidity and mortality. Approximately 90% of these patients carry loss-of-function mutations in the enzyme ferrochelatase (FECH), while 5% of cases are associated with activating mutations in the C-terminus of ALAS2. Recent work has begun to uncover novel mechanisms of heme regulation that may account for the remaining 5% of cases with previously unknown genetic basis. One erythropoietic protoporphyria family has been identified with inherited mutations in the AAA+ protease ClpXP that regulates ALAS activity. In this review article, recent findings on the role of ClpXP as both an activating unfoldase and degrading protease and its impact on heme synthesis will be discussed. This review will also highlight the role of ClpX dysfunction in erythropoietic protoporphyria.

Cimetidine/lactulose therapy ameliorates erythropoietic protoporphyria-related liver injury

A 21-year-old Japanese man was admitted to our hospital because of severe abdominal pain and jaundice. He had been suffering from abdominal pain attacks and liver dysfunction since 18 years of age. Liver histology showed amorphous brown deposits in the sinusoidal space and significant periportal fibrosis without apparent hepatitis. Increased protoporphyrin in serum and feces and ferrochelatase gene mutation confirmed the final diagnosis of erythropoietic protoporphyria (EPP). Since ursodeoxycholic acid (UDCA) intake and glucose infusion are insufficient to ameliorate jaundice and abdominal attacks, cimetidine and lactulose were added in order to suppress hepatic delta-aminolevulinic acid synthase and limit re-absorption of protoporphyrin, respectively. Afterwards, the jaundice, liver dysfunction and abdominal symptoms improved and UDCA, cimetidine, and lactulose administration was continued. A repeat biopsy at 1.5 years after adding cimetidine/lactulose revealed marked attenuation of periportal fibrosis and protoporphyrin deposits. As far as we know, this is the first demonstration of histological improvement of EPP-induced liver abnormalities due to persistent cimetidine/lactulose administration. These treatments may be useful for EPP-related liver injury.

Identification of FECH gene multiple variations in two Chinese patients with erythropoietic protoporphyria and a review

Erythropoietic protoporphyria (EPP), an autosomal dominant disease, is caused by partial deficiency of ferrochelatase (FECH), which catalyzes the terminal step of heme biosynthesis because of loss-of-function mutations in the FECH gene. To date, only a few cases have been described in Asia. In this study, we describe the clinical features of two Chinese patients with EPP, with diagnosis confirmed by the increase of free protoporphyrin in erythrocytes, detection of plasma fluorescence peak at 630-634 nm, and analysis of FECH gene mutations. Using gene scanning, we identified a small deletion in the FECH gene (c.973 delA) in one proband (patient A) and a pathogenic FECH mutation (c.1232 G>T) in the other (patient B) and also observed some nucleotide variations (c.798 C>G, c.921 A>G, IVS1-23 C>T, IVS3+23 A>G, IVS9+35 C>T, and IVS3-48 T>C) in these patients. The family pedigree of patient A was then established by characterization of the genotype of the patient's relatives. We also analyzed the potential perniciousness of the missense mutation with bioinformatic software, Polyphen and Sift. In summary, Chinese EPP patients have similar manifestations to those of Caucasians, and identification of the Chinese FECH gene mutations expands the FECH genotypic spectrum and may contribute to genetic counseling.

A metabolomic perspective of griseofulvin-induced liver injury in mice

Griseofulvin (GSF) causes hepatic porphyria in mice, which mimics the liver injury associated with erythropoietic protoporphyria (EPP) in humans. The current study investigated the biochemical basis of GSF-induced liver injury in mice using a metabolimic approach. GSF treatment in mice resulted in significant accumulations of protoporphyrin IX (PPIX), N-methyl PPIX, bile acids, and glutathione (GSH) in the liver. Metabolomic analysis also revealed bioactivation pathways of GSF that contributed to the formation of GSF-PPIX, GSF-GSH and GSF-proline adducts. GSF-PPIX is the precursor of N-methyl PPIX. A six-fold increase of N-methyl PPIX was observed in the liver of mice after GSF treatment. N-methyl PPIX strongly inhibits ferrochelatase, the enzyme that converts PPIX to heme, and leads to PPIX accumulation. Excessive PPIX in the liver results in bile duct blockage and disturbs bile acid homeostasis. The accumulation of GSH in the liver was likely due to Nrf2-mediated upregulation of GSH synthesis. In summary, this study provides the biochemical basis of GSF-induced liver injury that can be used to understand the pathophysiology of EPP-associated liver injury in humans.

Iron misregulation and neurodegenerative disease in mouse models that lack iron regulatory proteins

Iron regulatory proteins 1 and 2 (IRP1 and IRP2) are two cytosolic proteins that maintain cellular iron homeostasis by binding to RNA stem loops known as iron responsive elements (IREs) that are found in the untranslated regions of target mRNAs that encode proteins involved in iron metabolism. IRPs modify the expression of iron metabolism genes, and global and tissue-specific knockout mice have been made to evaluate the physiological significance of these iron regulatory proteins (Irps). Here, we will discuss the results of the studies that have been performed with mice engineered to lack the expression of one or both Irps and made in different strains using different methodologies. Both Irp1 and Irp2 knockout mice are viable, but the double knockout (Irp1(-/-)Irp2(-/-)) mice die before birth, indicating that these Irps play a crucial role in maintaining iron homeostasis. Irp1(-/-) mice develop polycythemia and pulmonary hypertension, and when these mice are challenged with a low iron diet, they die early of abdominal hemorrhages, suggesting that Irp1 plays an essential role in erythropoiesis and in the pulmonary and cardiovascular systems. Irp2(-/-) mice develop microcytic anemia, erythropoietic protoporphyria and a progressive neurological disorder, indicating that Irp2 has important functions in the nervous system and erythropoietic homeostasis. Several excellent review articles have recently been published on Irp knockout mice that mainly focus on Irp1(-/-) mice (referenced in the introduction). In this review, we will briefly describe the phenotypes and physiological implications of Irp1(-/-) mice and discuss the phenotypes observed for Irp2(-/-) mice in detail with a particular emphasis on the neurological problems of these mice.

Liver transplantation for acute-on-chronic liver failure from erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is an inherited disorder of the heme metabolic pathway that is characterized by accumulation of protoporphyrin in the blood, erythrocytes, and tissues, and cutaneous manifestations of photosensitivity, all resulting from abnormalities in ferrochelatase (FECH) activity due to mutations in the FECH gene. Protoporphyrin is excreted by the liver, and excess protoporphyrin leads to cholelithiasis with obstructive episodes and chronic liver disease, finally progressing to liver cirrhosis. Patients with end-stage EPP-associated liver disease require liver transplantation. We describe here a 31-year-old male patient with EPP who experienced acute-on-chronic liver failure and underwent deceased-donor liver transplantation. Surgical and postoperative care included specific shielding from exposure to ultraviolet radiation to prevent photosensitivity-associated adverse effects. The patient recovered uneventfully and was doing well 24 months after transplantation. Future prevention and treatment of liver disease are discussed in detail.

Liver disease and erythropoietic protoporphyria: A concise review

The porphyries are a group of metabolic disorders characterized by deficiencies in the activity of enzymes involved in the biosynthesis of heme. In erythropoietic protoporphyria (EPP), in the majority of cases an autosomal dominant disease, there is a mutation of the gene that encodes ferrochelatase (FECH). FECH deficiency is associated with increased concentrations of protoporphyrin in erythrocytes, plasma, skin and liver. The prevalence of this inherited disorder oscillates between 1:75 000 and 1:200 000. Clinical manifestations of EPP appear in early infancy upon first exposure to the sun. Nevertheless, approximately 5%-20% of patients with EPP develop liver manifestations. Retention of protoporphyrin in the liver is associated with cholestatic phenomena and oxidative stress that predisposes to hepatobiliary disease of varying degrees of severity, such as cholelithiasis, mild parenchymal liver disease, progressive hepatocellular disease with end-stage liver disease and acute liver failure. Liver damage is the major risk in EPP patients, so surveillance and frequent clinical and biochemical liver follow-up is mandatory. The diagnostic approach consists in detecting increased levels of protoporphyrin, decreased activity of FECH and genetic analysis of the FECH gene. A variety of non-surgical therapeutic approaches have been adopted for the management of EPP associated with liver disease, but none of these has been shown to be unequivocally efficacious. Nevertheless, some may have a place in preparing patients for liver transplantation. Liver transplantation does not correct the constitutional deficiency of FECH. Consequently, there is a risk of recurrence of liver disease after liver transplantation as a result of continuing overproduction of protoporphyrin. Some authors recommend that bone marrow transplantation should be considered in liver allograft recipients to prevent recurrence of hepatic disease.

The diagnosis and management of erythropoietic protoporphyria

Porphyrias are a group of metabolic disorders resulting from enzymatic defects in the heme biosynthetic pathway. Erythropoietic protoporphyria is thought to be the second most common porphyria seen in clinical practice. It is, however, commonly under-recognized and can lead to both cutaneous manifestations as well as derangement in hepatic function in a minority of patients. This review summarizes the current understanding of this disorder. Different treatment options are discussed with the goal of preventing liver damage. The roles of liver and bone marrow transplantation are also addressed.