Observational pilot study of multi-wavelength wearable light dosimetry for erythropoietic protoporphyria

BACKGROUND

Erythropoietic protoporphyria (EPP) causes painful light sensitivity, limiting quality of life. Our objective was to develop and validate a wearable light exposure device and correlate measurements with light sensitivity in EPP to predict and prevent symptoms.

METHODS

A wearable light dosimeter was developed to capture light doses of UVA, blue, and red wavelengths. A prospective observational pilot study was performed in which five EPP patients wore two light dosimeters for 3 weeks, one as a watch, and one as a shirt clip.

RESULTS

Standard deviation (SD) increases from the mean in the daily blue light dose increased the odds ratio (OR) for symptom risk more than the self-reported outdoor time (OR 2.76 vs. 2.38) or other wavelengths, and a one SD increase from the mean in the daily blue light wristband device dose increased the OR for symptom risk more than the daily blue light shirt clip (OR 2.45 vs. 1.62). The area under the receiver operator curve for the blue light wristband dose was 0.78, suggesting 78% predictive accuracy.

CONCLUSION

These data demonstrate that wearable blue light dosimetry worn as a wristband is a promising method for measuring light exposure and predicting and preventing symptoms in EPP.

Development and Content Validation of Novel Patient-Reported Outcome Measures to Assess Disease Severity and Change in Patients with Erythropoietic Protoporphyria: The EPP Impact Questionnaire (EPIQ)

Purpose

Erythropoietic protoporphyria (EPP), a rare inherited disorder, presents in early childhood with severe, painful phototoxicity, with significant impacts on health-related quality of life (HRQoL). Previous studies have not captured all concepts important to patients. Therefore, this study sought to develop a novel, comprehensive, and content valid patient-reported outcome (PRO) measure to assess the efficacy of new therapies.

Patients and Methods

Qualitative interviews were conducted with EPP participants and clinical experts to obtain views on concepts relevant to patients. Results informed the development of novel PROs, which were debriefed during subsequent combined concept elicitation and cognitive debriefing interviews.

Results

Twenty-three interviews were conducted with 17 adults and 6 adolescents with EPP. Concept elicitation revealed that participants experienced many symptoms with significant variability. The most common were burning, pain, swelling, and tingling. Tingling was the most common prodromal symptom, while burning was the most bothersome, and pain was the worst full reaction symptom. Participants reported being negatively impacted in their ability to do daily activities, and social and emotional functioning. Many reported impacted ability to work and be productive at their job. Participants reviewed and completed the newly developed PRO measures assessing full reactions and ability to do activities, as well as items to assess severity and change in severity of prodromal symptoms, full reactions, and EPP overall. All measures were found to be comprehensive, clear, and relevant.

Conclusion

PRO measures are needed to assess important aspects of HRQoL and evaluate therapeutic response. These PRO measures are unique in assessing overall severity and change in EPP.

Update on the Porphyrias

The porphyrias are a group of rare diseases, each resulting from a defect in a different enzymatic step of the heme biosynthetic pathway. They can be broadly divided into two categories, hepatic and erythropoietic porphyrias, depending on the primary site of accumulation of heme intermediates. These disorders are multisystemic with variable symptoms that can be encountered by physicians in any specialty. Here, we review the porphyrias and describe their clinical presentation, diagnosis, and management. We discuss novel therapies that are approved or in development. Early diagnosis is key for the appropriate management and prevention of long-term complications in these rare disorders.

Illuminating Dersimelagon: A Novel Agent in the Treatment of Erythropoietic Protoporphyria and X-Linked Protoporphyria

Erythropoietic protoporphyria (EPP) is a genetic disorder stemming from reduced ferrochelatase expression, the final enzyme in the pathway of heme biosynthesis. A closely related condition, X-linked protoporphyria (XLP), bears similar clinical features although it arises from the heightened activity of δ-aminolevulinic acid synthase 2 (ALAS2), the first and normally rate-controlling enzyme in heme biosynthesis in developing red blood cells. Both of these abnormalities result in the buildup of protoporphyrin IX, leading to excruciating light sensitivity and, in a minority of cases, potentially fatal liver complications. Traditionally, managing EPP and XLP involved sun avoidance. However, the emergence of innovative therapies, such as dersimelagon, is reshaping the therapeutic landscape for these conditions. In this review, we summarize salient features of the properties of dersimelagon, shedding light on its potential role in advancing our understanding of treatment options for EPP and XLP.

Cimetidine Does Not Inhibit 5-Aminolevulinic Acid Synthase or Heme Oxygenase Activity: Implications for Treatment of Acute Intermittent Porphyria and Erythropoietic Protoporphyria

Acute intermittent porphyria (AIP) is characterized by acute neurovisceral attacks that are precipitated by the induction of hepatic 5-aminolevulinic acid synthase 1 (ALAS1). In erythropoietic protoporphyria (EPP), sun exposure leads to skin photosensitivity due to the overproduction of photoreactive porphyrins in bone marrow erythroid cells, where heme synthesis is primarily driven by the ALAS2 isozyme. Cimetidine has been suggested to be effective for the treatment of both AIP and EPP based on limited case reports. It has been proposed that cimetidine acts by inhibiting ALAS activity in liver and bone marrow for AIP and EPP, respectively, while it may also inhibit the hepatic activity of the heme catabolism enzyme, heme oxygenase (HO). Here, we show that cimetidine did not significantly modulate the activity or expression of endogenous ALAS or HO in wildtype mouse livers or bone marrow. Further, cimetidine did not effectively decrease hepatic ALAS activity or expression or plasma concentrations of the putative neurotoxic porphyrin precursors 5-aminolevulinic acid (ALA) and porphobilinogen (PBG), which were all markedly elevated during an induced acute attack in an AIP mouse model. These results show that cimetidine is not an efficacious treatment for acute attacks and suggest that its potential clinical benefit for EPP is not via ALAS inhibition.

Evidence-based consensus guidelines for the diagnosis and management of erythropoietic protoporphyria and X-linked protoporphyria

Erythropoietic protoporphyria and X-linked protoporphyria are rare genetic photodermatoses. Limited expertise with these disorders among physicians leads to diagnostic delays. Here, we present evidence-based consensus guidelines for the diagnosis, monitoring, and management of erythropoietic protoporphyria and X-linked protoporphyria. A systematic literature review was conducted, and reviewed among subcommittees of experts, divided by topic. Consensus on guidelines was reached within each subcommittee and then among all members of the committee. The appropriate biochemical and genetic testing to establish the diagnosis is reviewed in addition to the interpretation of results. Prevention of symptoms, management of acute phototoxicity, and pharmacologic and nonpharmacologic treatment options are discussed. The importance of ongoing monitoring for liver disease, iron deficiency, and vitamin D deficiency is discussed with management guidance. Finally, management of pregnancy and surgery and the safety of other therapies are summarized. We emphasize that these are multisystemic disorders that require longitudinal monitoring. These guidelines provide a structure for evidence-based diagnosis and management for practicing physicians. Early diagnosis and management of these disorders are essential, particularly given the availability of new and emerging therapies.

A case of erythrogenic protoporphyria with thyrotoxicosis and liver dysfunction in an adult female

Erythropoietic protoporphyria (EPP) is an inherited metabolic disease caused by the deficiency in ferrochelatase (FECH) encoded by the FECH gene, and it is inherited in an autosomal recessive manner. EPP usually produces acute pain photosensitivity after exposure to sunlight in infancy or early childhood, and liver failure is the most serious associated complication. This article reported an adult female case of EPP complicated with thyrotoxicosis and liver dysfunction which is a rare condition. The patient's liver function improved after liver protection treatment, her thyroid function returned to normal, and her EPP symptoms improved significantly. Moreover, the c.286C>T gene mutation may be the pathogenic locus of EPP. For patients with abnormal liver function, the possibility of EPP should be considered after the common causes are excluded, and FECH gene detection should be done to confirm the diagnosis in time. When EPP is associated with thyrotoxicosis and liver dysfunction, priority may be given to hepatoprotective therapy.

Living-Donor Liver Transplantation for Erythropoietic Protoporphyria: A Case Report and Literature Review

Erythropoietic protoporphyria (EPP) is a very rare disease with an estimated prevalence of 1 in 200,000 individuals. Decreased ferrochelatase activity causes the accumulation of protoporphyrin in the body, and light exposure results in the generation of active oxygen, causing photosensitivity. Liver damage has the greatest influence on the prognosis, and liver transplantation is the only treatment option for patients with decompensated liver cirrhosis. We report a case of living-donor liver transplantation for decompensated liver cirrhosis associated with EPP. The patient was a 52-year-old male who led a normal life except for mild photosensitivity. When the patient was 37-year-old, hepatic dysfunction was noticed. At 48-year-old, high erythrocyte protoporphyrin levels, skin biopsy, and genetic tests resulted in a diagnosis of EPP. The patient underwent living- donor liver transplantation because of decompensated liver cirrhosis. In the operating room and intensive care unit, a special light-shielding film was applied to all light sources to block light with harmful wavelengths during treatment. Due to the need for special measures, a lecture on patients with EPP was given before surgery to deepen understanding among all medical professionals involved in the treatment. As a result, no adverse events occurred during the perioperative period, and the patient was discharged on the 46th post-operative day. Currently, the transplanted liver is functioning extremely well, and the patient is alive 3 years post-transplant. Herein, we describe a case of living donor liver transplantation for EPP with a brief literature review.

Absorption, metabolism, and excretion of [14 C]dersimelagon, an investigational oral selective melanocortin 1 receptor agonist, in preclinical species and healthy volunteers

Dersimelagon (formerly MT-7117) is a novel, orally administered nonpeptide small molecule selective agonist for melanocortin 1 receptor currently being investigated for the treatment of erythropoietic protoporphyria, X-linked protoporphyria, and diffuse cutaneous systemic sclerosis (dcSSc). Findings of studies evaluating the absorption, distribution, metabolism, and excretion (ADME) of dersimelagon following a single dose of [¹⁴ C]dersimelagon in healthy adult volunteers (N = 6) who participated in phase 1, single-center, open-label, mass balance study (NCT03503266), and in preclinical animal models are presented. Rapid absorption and elimination were observed following oral administration of [¹⁴ C]dersimelagon in clinical and nonclinical studies, with a mean T_max of 30 min in rats and 1.5 h in monkeys, and a median T_max of 2 h in humans. In rats, there was a widespread distribution of [¹⁴ C]dersimelagon-related material, but little or no radioactivity was detected in the brain or fetal tissues. In humans, elimination of radioactivity in urine was negligible (excretion of radioactivity into the urine: 0.31% of dose), and the primary route of excretion was feces, with more than 90% of the radioactivity recovered through 5 days postdose. Based on these findings, dersimelagon is not retained in the human body. Findings from humans and animals suggest dersimelagon is extensively metabolized to the glucuronide in the liver, which is eliminated in bile, and hydrolyzed to unchanged dersimelagon in the gut. The results to date for this orally administered agent elucidate the ADME of dersimelagon in human and animal species and support its continued development for the treatment of photosensitive porphyrias and dcSSc.

Phototesting in erythropoietic protoporphyria trials: A systematic review

Severe skin pain when exposed to long wave ultraviolet radiation or visible light is the main symptom of erythropoietic protoporphyria (EPP). Treatment options for EPP are inadequate and new treatments are needed but hampered by the lack of valid efficacy outcomes. Phototesting with well-defined illumination of the skin can be performed reliably. We aimed to provide an overview of phototest procedures used to evaluate EPP treatments. Systematic searches of Embase, MEDLINE and the Cochrane Library were performed. Searches identified 11 studies using photosensitivity as efficacy outcome. The studies used eight different phototest protocols. Illuminations were performed with a filtered high-pressure mercury arc, or a xenon arc lamp equipped with monochromator or filters. Some used broadband, others narrowband illumination. In all protocols phototests were performed on the hands or the back. Endpoints were minimal dose required to induce either first symptom of discomfort, erythema, urticaria or intolerable pain. Other endpoints were change in erythema intensity or diameter of any type of flare after exposure compared to before. In conclusion, protocols displayed extensive variability in illumination set-up and evaluation of phototest reactions. Implementation of a standardized phototest method will allow more consistent and reliable outcome evaluation in future therapeutic research of protoporphyric photosensitivity.

Definitive Confirmation of Erythropoietic Protoporphyria via Re-biopsy Three Years After Initial Liver Biopsy at Age 15

Erythropoietic protoporphyria (EPP) is a rare inherited disorder of porphyrin metabolism that can cause liver damage and cholestatic hepatocellular failure. We report a case of EPP in a teenaged male who underwent liver biopsy for investigation of liver dysfunction of unknown cause. The diagnosis was not made until a re-biopsy approximately three years later, when the patient presented with recurrent skin lesions and elevated blood and urinary protoporphyrin levels. The liver biopsies contained brownish deposits that exhibited birefringence under polarized light and porphyrin fluorescence under fluorescence spectroscopy. EPP should be considered in young patients with unexplained liver dysfunction, skin symptoms, and seasonal changes in symptoms. Fluorescence spectroscopy of liver biopsy tissue can be a useful tool in the diagnosis of EPP.

Quality-Adjusted Life Years in Erythropoietic Protoporphyria and Other Rare Diseases: A Patient-Initiated EQ-5D Feasibility Study

Erythropoietic protoporphyria (EPP) is an ultra-rare inborn error of metabolism characterised by painful phototoxic burn injuries after short exposure times to visible light. Patients with EPP are highly adapted to their condition which makes the quantification of their health-related quality of life (QoL) challenging. In the presented patient-initiated feasibility study, we describe a new approach to assess treatment benefits in EPP by measuring QoL with the generic EQ-5D instrument in five patients under long-term (≥two years) treatment with afamelanotide, the first approved therapy for EPP. For the study, we selected patients with EPP who in addition were affected by an involuntary treatment interruption (caused by a temporary reimbursement suspension) because we hypothesized that individuals who had previously unlearned their adaptation are better able to assess their life without treatment than treatment-naïve patients. QoL under treatment was comparable to the age-matched population norm, and retrospective results for a treatment interruption and phototoxic reaction time point were comparable to the QoL of patients with chronic neuropathic pain and acute burn injuries, respectively. The results were accepted by the National Institute for Health and Care Excellence in England for their evaluation of the cost-effectiveness of afamelanotide, i.e., the calculation of quality-adjusted life years.

An Enigmatic Case of Jaundice and Photosensitivity in an Adolescent

Erythropoietic protoporphyria (EPP) presents with nonblistering photosensitivity. Hepatobiliary manifestations are seen in around 5% cases and include cholelithiasis, elevations in liver enzymes, progressive jaundice, and end-stage liver disease. The diagnosis is suspected based on clinical features and elevated erythrocyte metal-free protoporphyrin and confirmed by genetic analysis showing loss-of-function mutations in the ferrochelatase (FECH) gene. We present an adolescent boy who presented with jaundice and photosensitivity with the liver biopsy showing deposition of brown pigments within the canaliculi and hepatocytes. This pigment showed Maltese cross birefringence on polarizing microscopy and Medusa-head appearance on electron microscopy. Genetic analysis revealed loss-of-function mutations in FECH. Introduction of EPP is an inborn error of heme biosynthesis caused by mutations in FECH with a prevalence of 1:75,000 to 1:200,000. We present a case of a 16-year-old adolescent boy with photosensitivity, abdominal pain, and jaundice with protoporphyrin deposition in the liver who was ultimately diagnosed with EPP based on genetic analysis.

Single-incision laparoscopic partial cecectomy for appendiceal mucocele in a patient with porphyria photosensitivity

Erythropoietic protoporphyria (EPP) is a rare hereditary subtype of cutaneous porphyria characterized by photosensitivity. Increased exposure to light irradiation may precipitate acute liver failure, and surgical light-induced intestinal burns and perforations are known to occur. We report a case of EPP in a patient who underwent laparoscopic partial cecectomy for appendiceal mucocele. A 55-year-old man with EPP was presented for treatment of appendiceal mucocele. A light test using two types of laparoscopes (Companies O and S) was performed preoperatively. Light from the laparoscope manufactured by Company O caused photosensitivity; this effect was not observed with light from the laparoscope manufactured by Company S. Therefore, we performed laparoscopic partial cecectomy through a single umbilical incision using the laparoscope from Company S. Except for the incision site, the patient's skin was completely covered using surgical drapes. No intra- or postoperative complications were observed. Histopathological examination of the resected specimen revealed a low-grade appendiceal mucinous neoplasm.

Reappraisal of liver transplantation for erythropoietic protoporphyria: A deadly combination of disease recurrence and biliary complication

BACKGROUND

Erythropoietic protoporphyria (EPP) is a rare inherited disorder that causes the accumulation of protoporphyrin in the erythrocytes, skin, and liver. Severe protoporphyric hepatopathy results in liver failure, requiring both liver and bone marrow transplantation as a life-saving procedure and to correct the underlying enzymatic defect, respectively.

CASE PRESENTATION

We report a 20-year-old man who underwent split liver transplantation using a right trisegment and caudate lobe graft for EPP-induced liver failure, but succumbed to a deadly combination of early relapse of EPP and subsequent, intractable, late-onset bile leakage from the cut surface of segment 4. EPP recurrence most likely created a high-risk situation for bile leakage from the non-communicating bile ducts of segment 4; therefore, this case shed light on the potential relationship between EPP recurrence and biliary complications.

CONCLUSION

Physicians should recognize the potentially rapid and life-threatening progression of protoporphyric hepatopathy that leads to liver failure. For young patients with EPP, LT and sequential BMT should thoroughly be considered by a multidisciplinary team as soon as hepatic reserve deterioration becomes evident. Split liver transplantation should preferably be avoided and appropriate post-transplant management is critical before protoporphyrin depositions to the bile duct and hepatocyte causes irreversible damage to the liver graft.

Recognized and Emerging Features of Erythropoietic and X-Linked Protoporphyria

Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are inherited disorders resulting from defects in two different enzymes of the heme biosynthetic pathway, i.e., ferrochelatase (FECH) and delta-aminolevulinic acid synthase-2 (ALAS2), respectively. The ubiquitous FECH catalyzes the insertion of iron into the protoporphyrin ring to generate the final product, heme. After hemoglobinization, FECH can utilize other metals like zinc to bind the remainder of the protoporphyrin molecules, leading to the formation of zinc protoporphyrin. Therefore, FECH deficiency in EPP limits the formation of both heme and zinc protoporphyrin molecules. The erythroid-specific ALAS2 catalyses the synthesis of delta-aminolevulinic acid (ALA), from the union of glycine and succinyl-coenzyme A, in the first step of the pathway in the erythron. In XLP, ALAS2 activity increases, resulting in the amplified formation of ALA, and iron becomes the rate-limiting factor for heme synthesis in the erythroid tissue. Both EPP and XLP lead to the systemic accumulation of protoporphyrin IX (PPIX) in blood, erythrocytes, and tissues causing the major symptom of cutaneous photosensitivity and several other less recognized signs that need to be considered. Although significant advances have been made in our understanding of EPP and XLP in recent years, a complete understanding of the factors governing the variability in clinical expression and the severity (progression) of the disease remains elusive. The present review provides an overview of both well-established facts and the latest findings regarding these rare diseases.

In vitro Assessment of Solar Filters for Erythropoietic Protoporphyria in the Action Spectrum of Protoporphyrin IX

Introduction: Subjects with erythropoietic protoporphyria rely on broad-spectrum sunscreens with high sun protection factor, which is not informative on efficacy in the absorption spectrum of protoporphyrin IX, spanning visible radiation and peaking around 408 nm. Photoactivation of protoporphyrin IX is responsible for painful skin photosensitivity in erythropoietic protoporphyria. The authors assessed the protective efficacy of six sunscreens in vitro in the absorption spectrum of protoporphyrin IX. Method: Transmittance measurements were performed in the 300-850 nm wavelengths on samples of six photoprotective products applied to polymethyl methacrylate plates. Porphyrin protection factor was calculated in the 300-700 nm region to provide a measurement for the efficacy of each product based on the action spectrum of protoporphyrin IX. Results: Product A showed the highest porphyrin protection factor among tested products with a median value of 4.22. Product A is a sunscreen containing organic filters, titanium dioxide and synthetic iron oxides, pigmentary grade active ingredients that absorb visible radiation. Other products showed inefficient protection in the visible, with transmittance between 75 and 95% at 500 nm. The low porphyrin protection factor of inorganic filter product B was attributed to particle micronization, as declared by the manufacturer. Conclusion: Adding porphyrin protection factor to sunscreen labeling could help patients with erythropoietic protoporphyria and other photosensitivity disorders identify products tailored on their specific needs. The development of sunscreens providing protection from visible radiation and excellent cosmetical tolerability could improve the lifestyle of patients with erythropoietic protoporphyria.

Cardiopulmonary bypass in a child with erythropoietic protoporphyria

Children with erythropoietic porphyria are generally under the care of paediatric dermatologists. When these children undergo major surgery, they are at risk of unusual complications due to their photosensitivity. Dermatologists may be consulted prior to surgery for advice. We describe a case of a child with erythropoietic porphyria undergoing open heart surgery, utilising an exchange transfusion alongside other strategies to minimise the risk of photosensitivity-induced haemolysis.

Iron, Heme Synthesis and Erythropoietic Porphyrias: A Complex Interplay

Erythropoietic porphyrias are caused by enzymatic dysfunctions in the heme biosynthetic pathway, resulting in porphyrins accumulation in red blood cells. The porphyrins deposition in tissues, including the skin, leads to photosensitivity that is present in all erythropoietic porphyrias. In the bone marrow, heme synthesis is mainly controlled by intracellular labile iron by post-transcriptional regulation: translation of ALAS2 mRNA, the first and rate-limiting enzyme of the pathway, is inhibited when iron availability is low. Moreover, it has been shown that the expression of ferrochelatase (FECH, an iron-sulfur cluster enzyme that inserts iron into protoporphyrin IX to form heme), is regulated by intracellular iron level. Accordingly, there is accumulating evidence that iron status can mitigate disease expression in patients with erythropoietic porphyrias. This article will review the available clinical data on how iron status can modify the symptoms of erythropoietic porphyrias. We will then review the modulation of heme biosynthesis pathway by iron availability in the erythron and its role in erythropoietic porphyrias physiopathology. Finally, we will summarize what is known of FECH interactions with other proteins involved in iron metabolism in the mitochondria.

Hematopoietic stem cell transplant for erythropoietic porphyrias in pediatric patients

Cutaneous, hematopoietic, and hepatic manifestations of congenital erythropoietic porphyria (CEP) and erythropoietic protoporphyria (EPP) can be debilitating. We present our institution's experience with five patients with porphyria who underwent hematopoietic stem cell transplant (HSCT). Four patients with CEP, including three under age 2, received myeloablation. One patient with EPP, with prior liver transplant, received reduced intensity conditioning (RIC). Four patients are alive without porphyria symptomology and with full donor chimerism. HSCT corrects the defective heme pathway and should be considered early in patients with severe erythropoietic porphyrias to minimize end-organ damage. RIC regimens can minimize toxicity in patients with comorbidities.

Inherited genetic late-onset erythropoietic protoporphyria: A systematic review of the literature

BACKGROUND

Inherited genetic erythropoietic protoporphyria (EPP) is characterized by a photosensitive rash that emerges during infancy or early childhood. Acquired EPP can erupt at any age, even during adulthood, and is associated with hematological disorders. A third, less-studied type of EPP is also inherited but appears later in life (during adulthood).

PURPOSE

To evaluate the characteristics of inherited genetic late-onset (IGLO) EPP.

METHODS

A systematic comprehensive search of the literature was conducted using PubMed, Google Scholar, ScienceDirect, and clinicaltrials.gov databases. Studies describing patients with IGLO EPP were included. Additionally, we present an index case of a patient, treated at our clinic in whom inherited genetic EPP was diagnosed at age 21 years.

RESULTS

The search yielded 1514 citations. Five publications were eligible for review. Along with our case, 7 patients (4 males) were included in the analysis. Mean age at disease onset was 34.2 years (range 18-69, median 30). Most patients presented with mild pruritus and rash in a photosensitive distribution. Mean level of free erythrocyte protoporphyrin IX (FEP) was 8.6 μmol/L. A mutant ferrochelatase gene (FECH) in trans to a hypomorphic FECH allele was found in 3 of the 4 patients who underwent genetic testing.

CONCLUSION

We describe the distinct features of IGLO EPP. This work emphasizes that a diagnosis of inherited genetic EPP should not be ruled out in adults with new-onset photosensitive manifestations.

Ultraviolet A phototest positivity is associated with higher free erythrocyte protoporphyrin IX concentration and lower transferrin saturation values in erythropoietic protoporphyria

BACKGROUND

Erythropoietic protoporphyria (EPP) is a rare disorder of heme biosynthesis hallmarked by early-onset photosensitivity and mainly due to defective ferrochelatase activity leading to increased erythrocyte protoporphyrin IX (PPIX) levels. Evidence regarding the relationship between erythrocyte PPIX concentration and photosensitivity is limited.

METHODS

To investigate the relationship between free erythrocyte PPIX (FEP) concentration; routine laboratory tests, particularly iron metabolism biomarkers; and ultraviolet (UV) A/visible light phototesting findings, 20 genetically confirmed EPP and one XLPP treatment-naive patients were included in our study. They underwent UVA and visible light phototesting. On the same day, blood samples were collected for measurement of FEP, serum iron, transferrin, transferrin saturation, and ferritin, 25-hydroxyvitamin D, and liver enzyme levels.

RESULTS

Median FEP concentration at the time of phototesting was 57.50 (IQR: 34.58-102.70) μg/g of Hb. UVA and visible light phototesting were positive in 9 (42.9%) and 8 (38.1%) patients, respectively. Median FEP concentration was significantly higher in UVA phototest-positive patients than in those negative (64.37 [IQR: 57.45-121.82] vs 45.35 [IQR: 24.53-74.61] μg/g of Hb, respectively; P = .04486). Similarly, UVA photosensitive individuals had significantly lower median serum iron levels (61.5 [IQR: 33.5-84] μg/dL vs 109 [IQR: 63.25-154] μg/dL, respectively; P = .01862) and transferrin saturation values (15.005 [IQR: 7.0775-18.41] % vs 29.645 [IQR: 17.8225-34.3575] %; P = .0109) than those negative.

CONCLUSIONS

Our study demonstrates that UVA phototest positivity is associated with higher FEP concentration and lower transferrin saturation and serum iron concentration in EPP.

Repurposing of glycine transport inhibitors for the treatment of erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is a rare disease in which patients experience severe light sensitivity. It is caused by a deficiency of ferrochelatase (FECH), the last enzyme in heme biosynthesis (HBS). The lack of FECH causes accumulation of its photoreactive substrate protoporphyrin IX (PPIX) in patients' erythrocytes. Here, we explored an approach for the treatment of EPP by decreasing PPIX synthesis using small-molecule inhibitors directed to factors in the HBS pathway. We generated a FECH-knockout clone from K562 erythroleukemia cells, which accumulates PPIX and undergoes oxidative stress upon light exposure. We used these matched cell lines to screen a set of publicly available inhibitors of factors in the HBS pathway. Inhibitors of the glycine transporters GlyT1 and GlyT2 lowered levels of PPIX and markers of oxidative stress selectively in K562^11B4 cells, and in primary erythroid cultures from an EPP patient. Our findings open the door to investigation of glycine transport inhibitors for HBS disorders.

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

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

Methods

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

Results

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

Conclusion

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

Plain Language summary

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

A Novel Mechanism for NF-κB-activation via IκB-aggregation: Implications for Hepatic Mallory-Denk-Body Induced Inflammation

Mallory-Denk-bodies (MDBs) are hepatic protein aggregates associated with inflammation both clinically and in MDB-inducing models. Similar protein aggregation in neurodegenerative diseases also triggers inflammation and NF-κB activation. However, the precise mechanism that links protein aggregation to NF-κB-activation and inflammatory response remains unclear. Herein we find that treating primary hepatocytes with MDB-inducing agents (N-methylprotoporphyrin (NMPP), protoporphyrin IX (PPIX), or Zinc-protoporphyrin IX (ZnPP)) elicited an IκBα-loss with consequent NF-κB activation. Four known mechanisms of IκBα-loss i.e. the canonical ubiquitin-dependent proteasomal degradation (UPD), autophagic-lysosomal degradation, calpain degradation and translational inhibition, were all probed and excluded. Immunofluorescence analyses of ZnPP-treated cells coupled with 8 M urea/CHAPS-extraction revealed that this IκBα-loss was due to its sequestration along with IκBβ into insoluble aggregates, thereby releasing NF-κB. Through affinity pulldown, proximity biotinylation by antibody recognition, and other proteomic analyses, we verified that NF-κB subunit p65, which stably interacts with IκBα under normal conditions, no longer binds to it upon ZnPP-treatment. Additionally, we identified 10 proteins that interact with IκBα under baseline conditions, aggregate upon ZnPP-treatment, and maintain the interaction with IκBα after ZnPP-treatment, either by cosequestering into insoluble aggregates or through a different mechanism. Of these 10 proteins, the nucleoporins Nup153 and Nup358/RanBP2 were identified through RNA-interference, as mediators of IκBα-nuclear import. The concurrent aggregation of IκBα, NUP153, and RanBP2 upon ZnPP-treatment, synergistically precluded the nuclear entry of IκBα and its consequent binding and termination of NF-κB activation. This novel mechanism may account for the protein aggregate-induced inflammation observed in liver diseases, thus identifying novel targets for therapeutic intervention. Because of inherent commonalities this MDB cell model is a bona fide protoporphyric model, making these findings equally relevant to the liver inflammation associated with clinical protoporphyria.

Clinical and molecular epidemiology of erythropoietic protoporphyria in Italy

BACKGROUND

Erythropoietic protoporphyria (EPP) is a rare inherited disease associated with heme metabolism, characterized by severe life-long photosensitivity and liver involvement.

OBJECTIVE

To provide epidemiological data of EPP in Italy.

MATERIALS & METHODS

Prospective/retrospective data of EPP patients were collected by an Italian network of porphyria specialist centres (Gruppo Italiano Porfiria, GrIP) over a 20-year period (1996-2017).

RESULTS

In total, 179 patients (79 females) with a clinical and biochemical diagnosis of EPP were assessed, revealing a prevalence of 3.15 cases per million persons and an incidence of 0.13 cases per million persons/year. Incidence significantly increased after 2009 (due to the availability of alfa-melanotide, which effectively limits skin photosensitivity). Mean age at diagnosis was 28 years, with only 22 patients (12.2%) diagnosed ≤10 years old. Gene mutations were assessed in 173 (96.6%) patients; most (164; 91.3%) were FECH mutations on one allele in association with the hypomorphic variant, c.315-48C, on the other (classic EPP), and nine (5.2%) were ALAS2 mutations (X-linked EPP). Only one case of autosomal recessive EPP was observed. Of the 42 different FECH mutations, 15 are novel, three mutations collectively accounted for 45.9% (75/164) of the mutations (c.215dupT [27.2%], c.901_902delTG [11.5%] and c.67 + 5G > A [7.2%]), and frameshift mutations were prevalent (33.3%). A form of light protection was used by 109/179 (60.8%) patients, and 100 (56%) had at least one α-melanotide implant. Three cases of severe acute liver involvement, requiring OLT, were observed.

CONCLUSION

These data define, for the first time, the clinical and molecular epidemiology of EPP in Italy.

Acquired erythropoietic protoporphyria: A systematic review of the literature

BACKGROUND

Erythropoietic protoporphyria (EPP) is a semi-dominantly inherited porphyria presenting with photosensitivity during early childhood. Acquired EPP has been reported; however, data regarding this rare disorder are scarce.

PURPOSE

To evaluate the characteristics of acquired EPP.

METHODS

A comprehensive search of PubMed, Google Scholar, ScienceDirect, and clinicaltrials.gov databases was performed by three reviewers. Studies describing patients with acquired EPP were included. Additionally, we present an index case of a 26-year-old patient who acquired clinically and biochemically typical EPP in association with myelodysplastic syndrome (MDS).

RESULTS

We included 20 case reports describing 20 patients. Most (80%) patients were male of mean age 58 ± 13 years. In all patients, acquired EPP was associated with hematological disease, most commonly MDS (85%) followed by myeloproliferative disease (10%). In 86% of cases, hematological disease led to abnormality or somatic mutation in chromosome 18q (the locus of the ferrochelatase gene). The mean erythrocyte protoporphyrin IX concentration was very high (4286 μg/dL). Most (90%) patients presented with photosensitivity, 20% experienced blistering, and 25% presented with hepatic insufficiency, both uncommon in EPP. In 55% of patients, hematological disease was diagnosed after occurrence of cutaneous symptoms. Beta-carotene led to partial control of symptoms in 5 patients and resolution in another patient. Azacitidine treatment of MDS led to resolution of cutaneous symptoms in three patients.

CONCLUSION

We present the distinct features of acquired EPP and highlight that any patient presenting with new-onset photosensitivity, irrespective of age should be evaluated for porphyria.

Erythropoietic Protoporphyria in a Japanese Population

Erythropoietic protoporphyria is caused by a partial deficiency of ferrochelatase, which is the last enzyme in the heme biosynthesis pathway. In a typical erythropoietic protoporphyria, photosensitivity initially appears, following the first exposure to the sun in early infancy or childhood. Erythropoietic protoporphyria has been reported worldwide, but there is a regional variation in its epidemiology. Approximately 20% of the Japanese patients were recognized to have symptoms of erythropoietic protoporphyria after 10 years of age. Physicians occasionally encounter Japanese patients with erythropoietic protoporphyria, mild symptoms and no FECH gene mutations. The homozygous IVS3-48C polymorphism may cause a mild phenotype of the erythropoietic protoporphyria via a slight increase in protoporphyrin. The frequency of the homozygous IVS3-48C polymorphism in the Japanese population is higher than that observed in European countries. Japanese type of erythropoietic protopor-phyria shows a characteristic phenotype of the late onset and mild symptoms compared to the Caucasian erythropoietic protoporphyria. This review describes the characteristics of erythropoietic protoporphyria in Japanese patients.

Afamelanotide in the Treatment of Dermatologic Disease

Afamelanotide, an α-melanocyte stimulating hormone analogue, has become an emerging therapeutic option for a variety of skin conditions previously refractory to other treatments. Its efficacy has been demonstrated in several dermatologic conditions, including erythropoietic protoporphyria (EPP), solar urticaria, polymorphic light eruption (PMLE), vitiligo, acne, and Hailey-Hailey disease. Its relatively low risk side effect profile makes it an attractive treatment option and also paves the way for innovative use in other disorders.

Prevention of photosensitivity with action spectrum adjusted protection for erythropoietic protoporphyria

Erythropoietic protoporphyria is a genetic disease characterized by sensitivity to sunlight caused by the accumulation of protoporphyrin IX. Photoprotection against ultraviolet A and visible light is necessary for erythropoietic porphyria patients because the absorption spectrum of protoporphyrin IX lies in both ultraviolet A and visible light region. We developed a novel index, in vitro porphyrin protection factor, based on the protoporphyrin IX absorbance spectrum. We also selected appropriate photoprotective products designed according to protoporphyrin IX absorbance. The porphyrin protection factors of a combination of make-up base with a powder as well as with a liquid foundation were significantly higher than those of a conventional sunscreen product, even at a small application dose. An in-use test carried out for 6 months showed that the efficacy of these products was 78.3%, and no adverse reactions were observed. Male subjects preferred liquid foundation, whereas all female subjects used powder foundation. The preference of the subjects could lead to the long-term use of the tested products. In conclusion, this study provided a new approach to improve photoprotection in erythropoietic protoporphyria patients.

Case of late-onset erythropoietic protoporphyria with myelodysplastic syndrome who has homozygous IVS3-48C polymorphism in the ferrochelatase gene

We report the case of a 42-year-old man with a 5-year history of myelodysplastic syndrome and photosensitivity who had developed painful erythema and blisters on sun-exposed sites. Histological examination of a mildly lichenified lesion on the dorsal finger revealed extensive deposits of a hyaline-like, periodic acid-Schiff-positive material around superficial dermal blood vessels. Laboratory tests showed elevated erythrocyte protoporphyrin and normal urinary porphyrins, suggesting a diagnosis of erythropoietic protoporphyria. Late-onset erythropoietic protoporphyria is rare and is usually associated with an acquired somatic mutation of the ferrochelatase gene secondary to a hematological malignancy such as myelodysplastic syndrome. DNA analysis revealed that our patient has the homozygous IVS3-48C polymorphism that is a low-expression variant of wild-type ferrochelatase allele.

Case Report of Patient With Erythropoietic Protoporphyria and Basal Cell Carcinoma Diagnoses

BACKGROUND

Basal cell carcinoma (BCC) is the most common nonmelanoma skin cancer. There is a clear association between BCC development and ultraviolet (UV) radiation. Erythropoietic protoporphyria (EPP) is an inherited porphyria disorder that is a result of protoporphyrin accumulation, typically manifesting with phototoxicity.

CASE SUMMARY

We report a case of a 24 year-old man with both EPP and BCC diagnoses. At the age of 4 years, the patient was diagnosed with EPP. The patient presented with a BCC on his nose at age 24 years, despite sun avoidance as the primary treatment for his EPP diagnosis.

CONCLUSION

Consider the diagnosis of BCC in a patient with EPP, despite sun avoidance.

Stereotactic Body Radiotherapy for Hepatocellular Carcinoma Resulting in a Durable Relapse-Free Survival: A Case Report

The standard of care for localized hepatocellular carcinoma (HCC) is surgical resection. For patients who decline or who are unfit for surgery, stereotactic body radiotherapy (SBRT) is emerging as a viable treatment approach. We present a case of a 77-year-old female in whom an early stage HCC was incidentally discovered. Given her religious edicts as a devout Jehovah's Witness and her subsequent desire to avoid a blood transfusion, she declined surgical resection or transplant due to the risk of hemorrhage. Ablative therapy was deemed inappropriate given the mass's size and location adjacent to the inferior vena cava and diaphragm. She was treated with definitive SBRT to a total dose of 60 Gy administered in three 20 Gy fractions every other day. She had a complete response to the treatment and remains without evidence of disease after 39 months of follow-up. Her only treatment-related side effect is a persistent CTCAE Grade 1 myositis on her back overlying the treatment area. We report this case to add to the growing body of literature suggesting SBRT as an effective and safe alternative treatment modality for HCC.

Homeostasis of iron and hepcidin in erythropoietic protoporphyria

BACKGROUND

Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are genetic abnormalities of heme synthesis that result in excess production of protoporphyrin and that manifest as severe photosensitivity. These disorders are often associated with iron deficiency anaemia (IDA). Our aim was to determine whether hepcidin is increased in EPP/XLP patients, resulting in decreased enteral iron absorption and IDA.

MATERIAL AND METHODS

Eight subjects with EPP, one with XLP and nine controls had baseline blood and urine samples collected, and thereafter were given oral ferrous sulphate (660 mg). Post-iron blood and urine samples were collected at 2, 4, 6 and 8 h. Blood counts, serum cytokines, ferritin and iron studies were analysed at baseline. Serum iron studies, serum and urine hepcidin, and erythropoietin (Epo) were analysed at baseline and subsequent time points.

RESULTS

At baseline, EPP-XLP subjects had lower mean blood haemoglobin (13·9/15·3 g/dL) and serum ferritin (31·6/115 ng/mL) than controls. Serum iron levels increased markedly in both cohorts. Mean serum and urine hepcidin levels were significantly lower in the EPP-XLP group at 4 and 8 h post-iron (serum - 4 h, 3·79/26·6, 8 h, 5·79/34·6 nM; urine - 4 h, 0·85/2·50, 8 h, 1·44/6·63 nM/mM creatinine). Serum cytokines and Epo were normal and not different between groups.

CONCLUSIONS

We conclude that serum and urine hepcidin are not inappropriately increased in EPP/XLP subjects at baseline and do not increase over time as serum iron increases after oral ferrous sulphate. Levels of serum cytokines and Epo are normal in EPP/XLP. The molecular basis for the iron-deficient phenotype in EPP/XLP remains unknown.

X-linked dominant protoporphyria: The first reported Japanese case

A 12-year-old boy with photosensitivity since 3 years of age presented with small concavities on both cheeks, the nasal root and the dorsal surface of both hands. According to the clinical features, erythropoietic protoporphyria (EPP) was suspected. Urine and blood samples were tested for porphyrin derivatives, which revealed a markedly elevated level of erythrocyte protoporphyrin (EP) and a diagnosis of EPP was made. The patient's mother had no photosensitivity, however, lesions appearing slightly as small scars were found on the dorsum of her right hand; his elder sister and father showed no rash. The EP levels were elevated in samples from his mother and mildly elevated in those from his elder sister and father. To obtain a definitive diagnosis, genetic analyses were performed using samples from all family members, which revealed no mutations in the ferrochelatase-encoding gene (FECH), which is responsible for EPP. Instead, a pathological mutation of the 5-aminolevulinic acid synthase-encoding gene (ALAS2) was identified in samples from the patient, his mother and his elder sister, confirming a definitive diagnosis of X-linked dominant protoporphyria (XLDPP). This is the first Japanese family reported to have XLDPP, demonstrating evidence of the condition in Japan. In addition, because XLDPP is very similar to EPP in its clinical aspects and laboratory findings, a genetic analysis is required for the differential diagnosis.

Bone marrow transplant for X-linked protoporphyria with severe hepatic fibrosis

XLP is an erythroid porphyria that results in variable cutaneous photosensitivity due to accumulation of protoporphyrin. The genetic defect in XLP is mutation of the gene ALAS2, resulting in gain of function for the erythroid enzyme 5-aminolevulinate synthase 2. Previous reports have shown that protoporphyrin-induced liver disease may also occur in XLP, occasionally severe enough to warrant liver transplantation; however, transplantation may be followed by injury to the graft due to continued presence of the underlying metabolic disorder in the bone marrow. We present a case of XLP with severe liver disease successfully treated with HPCT to avoid liver transplantation. The case also demonstrates the feasibility of reduced intensity transplant to provide engraftment sufficient for correction of porphyria and tolerability of reduced intensity conditioning containing TLI in the face of severe liver injury.

Erythropoietic protoporphyria without skin symptoms-you do not always see what they feel

Erythropoietic protoporphyria (EPP) is an inherited disorder of the porphyrin metabolism that often remains undiagnosed in children. We report on a 4-year-old girl who had been suffering for 1 year from recurrent painful crises affecting her hands, feet, and nose following sun exposure. Objective skin lesions were absent until the age of 6. Porphyrin analysis revealed elevated free erythrocyte protoporphyrin (FEP) levels confirming the diagnosis of EPP. This illustrates that skin lesions might be completely absent in children affected with EPP, a fact that has only been reported once previously. Because EPP can manifest with few and unspecific cutaneous symptoms or no skin lesions at all, like in this patient, the diagnosis of EPP might be delayed or missed. EPP should be excluded in all photosensitive children, especially when discomfort is disproportionate to the extent of the cutaneous lesions. The clinic, pathophysiology, diagnosis, complications, and therapy of EPP are discussed.