Treatment of recurrent allograft dysfunction with intravenous hematin after liver transplantation for erythropoietic protoporphyria

Ferrochelatase: Mapping the Intersection of Iron and Porphyrin Metabolism in the Mitochondria

Porphyrin and iron are ubiquitous and essential for sustaining life in virtually all living organisms. Unlike iron, which exists in many forms, porphyrin macrocycles are mostly functional as metal complexes. The iron-containing porphyrin, heme, serves as a prosthetic group in a wide array of metabolic pathways; including respiratory cytochromes, hemoglobin, cytochrome P450s, catalases, and other hemoproteins. Despite playing crucial roles in many biological processes, heme, iron, and porphyrin intermediates are potentially cytotoxic. Thus, the intersection of porphyrin and iron metabolism at heme synthesis, and intracellular trafficking of heme and its porphyrin precursors are tightly regulated processes. In this review, we discuss recent advances in understanding the physiological dynamics of eukaryotic ferrochelatase, a mitochondrially localized metalloenzyme. Ferrochelatase catalyzes the terminal step of heme biosynthesis, the insertion of ferrous iron into protoporphyrin IX to produce heme. In most eukaryotes, except plants, ferrochelatase is localized to the mitochondrial matrix, where substrates are delivered and heme is synthesized for trafficking to multiple cellular locales. Herein, we delve into the structural and functional features of ferrochelatase, as well as its metabolic regulation in the mitochondria. We discuss the regulation of ferrochelatase via post-translational modifications, transportation of substrates and product across the mitochondrial membrane, protein-protein interactions, inhibition by small-molecule inhibitors, and ferrochelatase in protozoal parasites. Overall, this review presents insight on mitochondrial heme homeostasis from the perspective of ferrochelatase.

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.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

Management of Patients With Erythropoietic Protoporphyria-Related Progressive Liver Disease

Erythropoietic protoporphyria (EPP) is an inherited metabolic disorder of heme synthesis resulting from overproduction of protoporphyrin IX (PPIX), which can lead to progressive liver disease characterized by recurrent EPP crises and end-stage liver disease. We used the Australian Transplant Registry to identify 5 patients referred for liver transplantation between 2008 and 2017. A total of 4 patients had EPP secondary to ferrochelatase deficiency, and 1 patient had X-linked EPP. No patient had follow-up with a specialist prior to the diagnosis of progressive liver disease. There were 3 patients who underwent orthotopic liver transplantation, whereas 2 died while on the transplant waiting list. Parenteral PPIX-lowering therapy was used in 4 patients and was effective in 3 patients, although 2 of these had rebound porphyria and worsening liver function following a decrease in the intensity of therapy. Early disease recurrence in the allograft following transplantation occurred in 2 patients requiring red cell exchange (RCE) to successfully attain and maintain low PPIX levels, but RCE was associated with hemosiderosis in 1 patient. Allogeneic stem cell transplantation (AlloSCT) was performed in 2 patients. One failed engraftment twice, whereas the second rejected the first graft but achieved full donor chimerism with a second graft and increased immunosuppression. In conclusion, our observations suggest that progressive liver disease needs parenteral PPIX-lowering treatment with the intensity adjusted to achieve a target Erc-PPIX level. Because EPP liver disease is universally recurrent, AlloSCT should be considered in all patients with adequate immunosuppression to facilitate engraftment. RCE appears to be effective for recurrent EPP liver disease but is associated with an increased risk of iron overload.

Perioperative Anesthetic Management of Patients Having Liver Transplantation for Uncommon Conditions

This review focuses on the perioperative anesthetic management of patients having liver transplantation (LT) performed for several uncommon indications or in combination with rare pathology. Conditions discussed in the article include Alagille syndrome, hypertrophic cardiomyopathy, Gilbert's syndrome, porphyria, Wilson's disease, and Budd-Chiari syndrome. In comparison to other indications, LT in these settings is infrequent because of the low incidence of these pathologies. Most of these conditions (with the exception of Gilbert syndrome) are associated with a high probability of significant perioperative complications and increased mortality and morbidity. Experience in management of these unusual conditions is only gained over time. Developing clinical pathways for patients with these conditions should result in outcomes similar to LT performed for more common indications.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice-Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Seventh Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

Effects of hemin on heme oxygenase-1, gastric emptying, and symptoms in diabetic gastroparesis

BACKGROUND

Therapeutic options for management of diabetic gastroparesis are limited. Failure to maintain upregulation of heme oxygenase (HO1) leads to loss of interstitial cells of Cajal and delayed gastric emptying (GE) in non-obese diabetic mice. Our hypothesis was that hemin upregulation of HO1 would restore normal GE in humans with gastroparesis.

AIMS

To compare effects of hemin and placebo infusions on HO1 activity and protein, GE, autonomic function, and gastrointestinal symptoms in diabetic gastroparesis.

METHODS

In a single-center, double-blind, placebo-controlled, randomized clinical trial, we compared intravenous hemin, prepared in albumin, or albumin alone (placebo) in 20 patients, aged 41 ± 5 (SEM) years with diabetic gastroparesis. After infusions on days 1, 3, and 7, weekly infusions were administered for 7 additional weeks. Assessments included blood tests for HO1 protein and enzyme activity levels, GE with ¹³ C-spirulina breath test, autonomic functions (baseline and end), and gastrointestinal symptoms every 2 weeks.

KEY RESULTS

Nine of 11 patients randomized to hemin completed all study procedures. Compared to placebo, hemin increased HO1 protein on days 3 (p = 0.0002) and 7 (p = 0.008) and HO1 activity on day 3 (p = 0.0003) but not after. Gastric emptying, autonomic functions, and symptoms did not differ significantly in the hemin group relative to placebo.

CONCLUSIONS & INFERENCES

Hemin failed to sustain increased HO1 levels beyond a week and did not improve GE or symptoms in diabetic gastroparesis. Further studies are necessary to ascertain whether more frequent hemin infusions or other drugs would have a more sustained effect on HO1 and improve GE.

Protoporphyrin IX: the Good, the Bad, and the Ugly

Protoporphyrin IX (PPIX) is ubiquitously present in all living cells in small amounts as a precursor of heme. PPIX has some biologic functions of its own, and PPIX-based strategies have been used for cancer diagnosis and treatment (the good). PPIX serves as the substrate for ferrochelatase, the final enzyme in heme biosynthesis, and its homeostasis is tightly regulated during heme synthesis. Accumulation of PPIX in human porphyrias can cause skin photosensitivity, biliary stones, hepatobiliary damage, and even liver failure (the bad and the ugly). In this work, we review the mechanisms that are associated with the broad aspects of PPIX. Because PPIX is a hydrophobic molecule, its disposition is by hepatic rather than renal excretion. Large amounts of PPIX are toxic to the liver and can cause cholestatic liver injury. Application of PPIX in cancer diagnosis and treatment is based on its photodynamic effects.

Heme status affects human hepatic messenger RNA and microRNA expression

AIM: To assess effects of heme on messenger RNA (mRNA) and microRNA (miRNA) profiles of liver cells derived from humans.

METHODS: We exposed human hepatoma cell line Huh-7 cells to excess iron protoporphyrin (heme) (10 μmol/L) or induced heme deficiency by addition of 4, 6-dioxoheptanoic acid (500 μmol/L), a potent inhibitor of aminolevulinic acid dehydratase, for 6 h or 24 h. We harvested total RNA from the cells and performed both mRNA and miRNA array analyses, with use of Affymetrix chips, reagents, and instruments (human genome U133 plus 2.0 and miRNA 2.0 arrays). We assessed changes and their significance and interrelationships with Target Scan, Pathway Studios, and Ingenuity software.

RESULTS: Changes in mRNA levels were most numerous and striking at 6 h after heme treatment but were similar and still numerous at 24 h. After 6 h of heme exposure, the increase in heme oxygenase 1 gene expression was 60-fold by mRNA and 88-fold by quantitative reverse transcription-polymerase chain reaction. We found striking changes, especially up-regulation by heme of nuclear erythroid-2 related factor-mediated oxidative stress responses, protein ubiquitination, glucocorticoid signaling, P53 signaling, and changes in RNAs that regulate intermediary metabolism. Fewer mRNAs were down-regulated by heme, and the fold decreases were less exuberant than were the increases. Notable decreases after 24 h of heme exposure were patatin-like phospholipase domain-containing protein 3 (-6.5-fold), neuronal PAS domain protein 2 (-1.93-fold), and protoporphyrinogen oxidase (-1.7-fold).

CONCLUSION: Heme excess exhibits several toxic effects on liver and kidney, which deserve study in humans and in animal models of the human porphyrias or other disorders.

Plasma and red cell exchange transfusions for erythropoietic protoporphyria: a case report and review of the literature

Erythropoietic protoporphyria (EPP) is a rare and usually autosomal dominant disorder characterized by ferrochelatase deficiency and accumulation of protoporphyrin in red blood cells (RBCs), skin, and liver. A small minority of patients develop severe liver dysfunction for which optimum treatment is lacking. Therapeutic plasma exchange (TPE) and RBC exchange (RCE) have been anecdotally reported to benefit patients with EPP and liver failure. A 50-year-old female with EPP developed severe liver dysfunction after knee replacement surgery and high-dose acetaminophen use. Liver biopsy showed cholestatic liver injury without fibrosis. A total of 20 TPE procedures, six RCE procedures, and then 14 more TPE procedures were performed as adjunctive therapy with the purpose of preventing progression to end-stage liver failure. After initial TPE, the plasma and RBC protoporphyrin levels decreased from 834.9 to 180.4 μg/dL (normal, ≤1 μg/dL), and from 3,905 to 2,879 μg/dL (normal, ≤80 μg/dL), respectively, without liver function improvement. RCE decreased RBC protoporphyrin levels from 2,879 to 1,225 μg/dL but plasma protoporphyrin increased from 180.4 to 1,044.1 μg/dL, and liver function failed to improve. Additional TPE again stabilized plasma protoporphyrin and improved RBC protoporphyrin levels but the patient ultimately died owing to end-stage liver disease complications. This case illustrates that TPE and RCE may improve the plasma and RBC biochemical markers of EPP activity but liver function abnormalities may persist and patients may still progress to liver failure either because of irreversible liver injury or independent pathobiological factors unrelated to EPP-induced hepatotoxicity.

Involvement of heme oxygenase-1 in β-cyclodextrin-hemin complex-induced cucumber adventitious rooting process

Our previous results showed that β-cyclodextrin-hemin complex (CDH) exhibited a vital protective role against cadmium-induced oxidative damage and toxicity in alfalfa seedling roots by the regulation of heme oxygenase-1 (HO-1) gene expression. In this report, we further test whether CDH exhibited the hormonal-like response. The application of CDH and an inducer of HO-1, hemin, were able to induce the up-regulation of cucumber HO-1 gene (CsHO1) expression and thereafter the promotion of adventitious rooting in cucumber explants. The effect is specific for HO-1 since the potent HO-1 inhibitor zinc protoporphyrin IX (ZnPP) blocked the above responses triggered by CDH, and the inhibitory effects were reversed further when 30% saturation of CO aqueous solution was added together. Further, molecular evidence showed that CDH triggered the increases of the HO-1-mediated target genes responsible for adventitious rooting, including one DnaJ-like gene (CsDNAJ-1) and two calcium-dependent protein kinase (CDPK) genes (CsCDPK1 and CsCDPK5), and were inhibited by ZnPP and reversed by CO. The calcium (Ca2+) chelator ethylene glycol-bis (2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA) and the Ca2+ channel blocker lanthanum chloride (LaCl3) not only compromised the induction of adventitious rooting induced by CDH but also decreased the transcripts of above three target genes. However, the application of ascorbic acid (AsA), a well-known antioxidant in plants, failed to exhibit similar inducible effect on adventitious root formation. In short, above results illustrated that the response of CDH in the induction of cucumber adventitious rooting might be through HO-1-dependent mechanism and calcium signaling.

KEY MESSAGE

Physiological, pharmacological and molecular evidence showed that β-cyclodextrin-hemin complex (CDH) was able to induce cucumber adventitious rooting through heme oxygenase-1 (HO-1)-dependent mechanism and calcium signaling.

Nitric oxide is involved in hemin-induced cucumber adventitious rooting process

Hemin, a heme oxygenase-1 (HO-1) inducer, was shown to exert numerous beneficial physiological functions in animals. Our previous study suggests that HO-1/carbon monoxide (CO) acts as a novel downstream signal system in the auxin-induced adventitious rooting. The objective of this study was to test whether nitric oxide (NO) is involved in hemin-induced cucumber adventitious rooting. Applications of hemin or CO aqueous solution to auxin-depleted cucumber explant induced up-regulation of cucumber HO-1 transcripts (CsHO1), NO production, and thereafter adventitious root formation, and some above responses were blocked by the combination treatment with two nitric oxide synthase (NOS)-like enzyme inhibitors N(G)-nitro-L-arginine methylester hydrochloride and N(G)-nitro-L-arginine, a HO-1 specific inhibitor zinc protoporphyrin IX, and a specific NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt. However, these blocking responses were not observed using tungstate, an inhibitor of nitrate reductase, another NO producing enzyme in plants. Furthermore, the guanylate cyclase inhibitors 1H-(1,2,4)-oxadiazole[4,3-a]quinoxalin-1-one and 6-anilino-5,8-quinolinedione reduced root development induced by hemin, whereas the cell-permeable cyclic guanosine monophosphate (cGMP) derivative 8-Br-cGMP reversed this effect. Together, our results indicated that at least in our experimental conditions, NO might operate downstream of hemin promoting adventitious root formation probably in a cGMP-dependent manner.

Photosensitivity and acute liver insufficiency in late-onset erythropoietic protoporphyria with a chromosome 18q abnormality

Late-onset erythropoietic protoporphyria (EPP) is rare, and it is usually associated with an acquired somatic mutation of the ferrochelatase gene secondary to hematological malignancy such as myelodysplastic syndrome or myeloproliferative disorder. In 0.5–1% of patients with EPP, deposition of protoporphyrin in the liver leads to progressive liver insufficiency. Herein, we report the case of a 67-year-old female who developed EPP with typical photosensitivity and hemolytic anemia. Six months later, she was admitted with acute liver damage with a rapidly progressing course, and developed liver insufficiency. She recovered from the liver insufficiency after undergoing plasmapheresis and red blood cell exchange transfusion. A bone marrow examination revealed normal features; however, a cytogenetic analysis identified an abnormal clone of cells with a translocation between chromosomes 13q12 and 18q21.1. This is the first report of a patient who recovered from liver insufficiency. The results of this report suggest that plasmapheresis and red blood cell exchange transfusion are effective for treating liver insufficiency in patients with late-onset EPP.

Protective role of heme oxygenase-1 against inflammation in atherosclerosis

Heme oxygenase-1 (HO-1) catalyzes the first and rate-limiting step in the metabolism of free heme into equimolar amounts of ferrous iron, carbon monoxide (CO), and biliverdin. Biliverdin is subsequently converted to bilirubin by biliverdin reductase. HO-1 has recently been identified as a promising therapeutic target in the treatment of vascular inflammatory disease, including atherosclerosis. HO-1 represses inflammation by removing the pro-inflammatory molecule heme and by generating CO and the bile pigments, biliverdin and bilirubin. These HO-1 reaction products are capable of blocking innate and adaptive immune responses by modifying the activation, differentiation, maturation, and/or polarization of numerous immune cells, including endothelial cells, monocytes/macrophages, dendritic cells, T lymphocytes, mast cells, and platelets. These cellular actions by CO and bile pigments result in diminished leukocyte recruitment and infiltration, and pro-inflammatory mediator production within atherosclerotic lesions. This review highlights the mechanisms by which HO-1 suppresses vascular inflammation in atherosclerosis, and explores possible therapeutic modalities by which HO-1 and its reaction products can be employed to ameliorate vascular inflammatory disease.

UK experience of liver transplantation for erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is characterised by excess production of free protoporphyrin from the bone marrow, most commonly due to deficiency of the enzyme ferrochelatase. Excess protoporphyrin gives rise to the cutaneous photosensitivity characteristic of the disease, and in a minority of patients leads to end-stage liver disease necessitating liver transplantation (LT). There is limited information regarding the timing, impact and long-term outcome of LT in such patients, thus we aimed to identify the indications and outcomes of all transplants performed for EPP in the UK using data from the UK Transplant Registry. Between 1987 and 2009, five patients underwent LT for EPP liver disease. Median follow-up was 60 months, and there were two deaths at 44 and 95 months from causes unrelated to liver disease. The remaining recipients are alive at 22.4 years, 61 months and 55 months after transplant. A high rate of postoperative biliary stricturing requiring multiple biliary interventions was observed. Recurrent EPP-liver disease occurred in 4/5 (80%) of patients but graft failure has not been observed. Given the role of biliary obstruction in inducing EPP-mediated liver damage, we suggest that consideration should be given for construction of a Roux loop at the time of transplant. Thus we demonstrate that although EPP liver transplant recipients have a good long-term survival, comparable to patients undergoing LT for other indications, biliary complications and disease recurrence are almost universal, and bone marrow transplantation should be considered where possible.

Targeting heme oxygenase-1 in vascular disease

Heme oxygenase-1 (HO-1) metabolizes heme to generate carbon monoxide (CO), biliverdin, and iron. Biliverdin is subsequently metabolized to bilirubin by biliverdin reductase. HO-1 has recently emerged as a promising therapeutic target in the treatment of vascular disease. Pharmacological induction or gene transfer of HO-1 ameliorates vascular dysfunction in animal models of atherosclerosis, post-angioplasty restenosis, vein graft stenosis, thrombosis, myocardial infarction, and hypertension, while inhibition of HO-1 activity or gene deletion exacerbates these disorders. The vasoprotection afforded by HO-1 is largely attributable to its end products: CO and the bile pigments, biliverdin and bilirubin. These end products exert potent anti-inflammatory, antioxidant, anti-apoptotic, and anti-thrombotic actions. In addition, CO and bile pigments act to preserve vascular homeostasis at sites of arterial injury by influencing the proliferation, migration, and adhesion of vascular smooth muscle cells, endothelial cells, endothelial progenitor cells, or leukocytes. Several strategies are currently being developed to target HO-1 in vascular disease. Pharmacological induction of HO-1 by heme derivatives, dietary antioxidants, or currently available drugs, is a promising near-term approach, while HO-1 gene delivery is a long-term therapeutic goal. Direct administration of CO via inhalation or through the use of CO-releasing molecules and/or CO-sensitizing agents provides an attractive alternative approach in targeting HO-1. Furthermore, delivery of bile pigments, either alone or in combination with CO, presents another avenue for protecting against vascular disease. Since HO-1 and its products are potentially toxic, a major challenge will be to devise clinically effective therapeutic modalities that target HO-1 without causing any adverse effects.

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.

Delayed immune recovery following sequential orthotopic liver transplantation and haploidentical stem cell transplantation in erythropoietic protoporphyria

A nine-yr-old boy with EPP suffered from severe skin burns and liver failure caused by progressive cholestasis and fibrosis. OLT was performed without major complications. Four months following liver transplantation he underwent parental haploidentical HSCT. The myeloablative conditioning regimen was relatively well tolerated and hematological engraftment was rapid (on day 10). Protoporphyrin concentrations returned to normal following HSCT. However, immune recovery was significantly delayed. Varicella zoster virus reactivation resulted in impaired vision, prolonged hospitalization and eventually in multiorgan failure and death. Sequential liver and haploidentical HSCT proved feasible though a high risk procedure in this EPP patient. The management of post-IST after these combined transplantations remains a challenge and needs to be further established.

First-in-human study demonstrating pharmacological activation of heme oxygenase-1 in humans

Heme oxygenase (HO)-1 degrades heme and protects against oxidative stress, but it has not been pharmacologically induced in humans. In this randomized study of 10 healthy volunteers, hemin (3 mg/kg intravenously in 25% albumin) was shown to increase plasma HO-1 protein concentration four- to fivefold and HO-1 activity ~15-fold relative to baseline at 24 and 48 h (placebo -56.41 +/- 6.31 (baseline), 69.79 +/- 13.00 (24 h), 77.44 +/- 10.62 (48 h) vs. hemin -71.70 +/- 9.20 (baseline), 1,126.20 +/- 293.30 (24 h), 1,192.20 +/- 333.30 (48 h)) in four of five subjects as compared with albumin alone (P </= 0.03). This represents the overcoming of a fundamental hurdle to HO-1 research in humans.

Erythropoietic protoporphyria

Erythropoietic protoporphyria (EPP) is an inherited disorder of the haem metabolic pathway characterised by accumulation of protoporphyrin in blood, erythrocytes and tissues, and cutaneous manifestations of photosensitivity. EPP has been reported worldwide, with prevalence between 1:75,000 and 1:200,000. It usually manifests in early infancy upon the first sun exposures. EPP is characterised by cutaneous manifestations of acute painful photosensitivity with erythema and oedema, sometimes with petechiae, together with stinging and burning sensations upon exposure to sunlight, without blisters. These episodes have a variable severity depending on the exposure duration and may result in chronic permanent lesions on exposed skin. As protoporphyrin is a lipophilic molecule that is excreted by the liver, EPP patients are at risk of cholelithiasis with obstructive episodes, and chronic liver disease that might evolve to rapid acute liver failure. In most patients, EPP results from a partial deficiency of the last enzyme of the haem biosynthetic pathway, ferrochelatase, EC 4.99.1.1/FECH (encoded by the FECH gene). EPP appears to be inherited as an autosomal dominant disease, the clinical expression of which is modulated by the presence of the hypomorphic FECH IVS3-48C allele trans, but recessive inheritance with two mutated FECH alleles has also been described. In about 2% of patients, overt disease was recently shown to be caused by gain-of-function mutations in the erythroid-specific aminolevulinic acid synthase 2 (ALAS2/ALAS, EC 2.3.1.27) gene and named X-linked dominant protoporphyria. Diagnosis is established by finding increased levels of protoporphyrin in plasma and red blood cells, and detection of a plasma fluorescence peak at 634 nm. Investigations for hepatic involvement, ferrochelatase activity level, genetic analysis (FECH mutations, presence of the hypomorphic FECH IVS3-48C allele trans and ALAS2 mutations) and family studies are advisable. Differential diagnosis includes phototoxic drug reactions, hydroa vacciniforme, solar urticaria, contact dermatitis, angio-oedema and, in some cases, other types of porphyria. Management includes avoidance of exposure to light, reduction of protoporphyrin levels and prevention of progression of possible liver disease to liver failure. As the major risk in EPP patients is liver disease, a regular follow-up of hepatic involvement is essential. Sequential hepatic and bone marrow transplantation should be considered as a suitable treatment for most severe cases of EPP with hepatic involvement. EPP is a lifelong disorder whose prognosis depends on the evolution of the hepatic disease. However, photosensitivity may have a significant impact on quality of life of EPP patients.

Effect of the heme oxygenase inducer hemin on blood haemostasis measured by high-frequency ultrasound

1. Heme compounds, like hemin, a heme oxygenase-1 inducer, are used in the treatment of acute porphyria treatment. The side-effects of hemin on haemostasis have been reported. To address those effects, in the present study we used a sensitive, high-frequency ultrasound technique to record acoustic velocity and to investigate whole blood clotting in Wistar rats treated chronically with hemin (50 mg/kg per day). 2. The hemin-induced disturbances in haemostasis measured were comparable to the heparin reference treatment, with a significant decrease in clotting velocity in both groups compared with controls (e.g. the time to clot was 40 +/- 5, 53 +/- 13 and 10 +/- 2 min, respectively; P < 0.05). Precautions must be taken when using high doses of hemin or in the treatment of bleeding diseases. 3. Further investigations are required to explore the effects of hemin in thrombosis models, because it could be a promising 'old drug' for the treatment of venous thrombosis in patients.

Liver transplantation for porphyria: who, when, and how?

Porphyrias are a heterogenous group of diseases that may result in disabling or life threatening neurovisceral symptoms and/or cutaneous photosensitivity. In acute intermittent porphyria, the clinical features, particularly neurological symptoms, may be life-threatening and disabling. Conventional treatment with human hemin, though effective in reducing symptoms, does not reverse neuropathy when structural nerve damage has occurred and may cause intense phlebitis. Liver transplantation (LT) may be considered as treatment for those with repeated life-threatening acute attacks resulting in poor quality of life, requirement of ventilatory support, and progressive loss of venous access due to hemin infusion. Patients with variegate porphyria (VP) present after puberty with neurovisceral symptoms and skin manifestations. LT resolved VP in the 1 patient reported in the literature. Aminolaevulinic acid dehydratase deficient porphyria is a rare autosomal recessive disorder and a child who presented with failure to thrive and required transfusions and parenteral nutrition did not improve with LT. In erythropoietic protoporphyria (EPP), there is excessive production of protoporphyrin in the bone marrow. Protoporphyrin is hepatotoxic and pigment loading of hepatocytes and bile canalicular sludging may result in progressive cholestasis and cirrhosis. LT is beneficial for such patients with end-stage liver disease. Perioperative management includes use of filters on operative lights to prevent skin burns and intestinal perforation. Other concerns include development of neuropathy, biliary complications, and recurrent liver disease. This review addresses the rationale, patient selection, evaluation, management issues, and technique of performing LT in various types of porphyria.

Recurrence of nonviral diseases

As long-term graft survival and mortality after liver transplantation improve, recognition that allografts may be affected by the same disease process that resulted in the failure of the liver is of both clinical and academic importance. Recipients need to be counseled about recurrence and potential impact on graft function and graft survival; clinicians need to be aware of the potential of recurrence to interpret the clinical, laboratory, radiologic, and histologic findings and alter management. Understanding which conditions recur in the allograft and factors associated with recurrence may shed light on pathogenesis. This article discusses the recurrence of nonviral diseases after liver transplantation, diagnosis, and management.

Curative bone marrow transplantation in erythropoietic protoporphyria after reversal of severe cholestasis

We report the case of a middle-age patient presenting with severe progressive protoporphyric cholestasis. To halt further progression of liver disease, medical treatment was given aimed at different mechanisms possibly causing cholestasis in erythropoietic protoporphyria. Within eighty days, liver biochemistry completely normalized and liver histology markedly improved. Bone marrow transplantation was performed to prevent relapse of cholestatic liver disease by correcting the main site of protoporphyrin overproduction. Thirty-three months after cholestatic presentation and ten months after bone marrow transplantation, liver and porphyrin biochemistry remains normal. The patient is in excellent condition and photosensitivity is absent. The theoretical role of each treatment used to successfully reverse cholestasis and the role of bone marrow transplantation in erythropoietic protoporphyria are discussed. Medical treatment can resolve hepatic abnormalities in protoporphyric cholestasis. Bone marrow transplantation achieves phenotypic reversal and may offer protection from future protoporphyric liver disease.

Sequential liver and bone marrow transplantation for treatment of erythropoietic protoporphyria

Erythropoietic protoporphyria is a disorder of heme synthesis in which deficient ferrochelatase activity leads to excess production and biliary excretion of protoporphyrin. The main clinical features, photosensitivity and hepatobiliary disease that may progress to liver failure, are caused by the toxicity of protoporphyrin. Liver transplantation has been used to treat liver failure in erythropoietic protoporphyria, but excess production of protoporphyrin by the bone marrow continues causing recurrence of liver disease in the majority of patients. This is the first report of successful sequential liver and bone marrow transplantation in a patient with liver failure as a result of erythropoietic protoporphyria. This combination corrected the severe phenotype, resolving the severe photosensitivity and halting erythropoietic protoporphyria associated liver graft injury. Splenectomy seemed to facilitate the successful bone marrow transplant.

Hemin Activation Ameliorates HIV-1 Infection via Heme Oxygenase-1 Induction

Hemin, a critical component of hemoglobin, is an active ingredient of a biologic therapeutic approved by the Food and Drug Administration for the treatment of acute porphyries. This report describes a biological function of this molecule in inducing host defense against HIV-1 infection via heme oxygenase-1 (HO-1) induction. Treatment of monocytes with hemin substantially inhibited HIV replication, as evident by nearly undetectable viral RNA and cell-free HIV-1 p24 protein in a dose-dependent manner. Hemin exposure of these cells before infection, at the time of infection, or after infection caused >90% reduction of HIV DNA with substantially low levels of HIV-1 p24 and HIV-associated cytopathic effects. In addition, hemin treatment significantly suppressed infection of both monocytes and T cells inoculated with R5, X4, R5X4 tropic strains, and reverse transcriptase-resistant, azidothymidine-resistant, ddC/ddI-resistant, nivirapine-resistant, and other clinical HIV isolates. Intraperitoneal administration of hemin 4 days after HIV infection reduced viral load in the serum of human PBMC-reconstituted nonobese diabetic SCID mice by >6-fold. Suppression of HIV replication in hemin-activated cells correlated with the induction of HO-1 and was attenuated by tin protoporphyrin (SnPP) IX, an inhibitor of HO-1 activity, suggesting a pivotal role of this endogenous enzyme in the regulation of HIV infection. Hemin-induced HO-1 induction in the CCR-5, CXCR-4, and CD4 coexpressing GHOST(3) cells was consistent with the inhibition of Tat-dependent activation of long terminal repeat promoter leading to reduced GFP expression. These findings suggest an important role of hemin-induced HO-1 activity as a host defense mechanism against HIV-1 infection.

Photosensitivity and acute liver injury in myeloproliferative disorder secondary to late-onset protoporphyria caused by deletion of a ferrochelatase gene in hematopoietic cells

Late-onset erythropoietic protoporphyria (EPP) is a rare complication of myelodysplastic syndrome (MDS) but has not been described in association with a myeloproliferative disorder (MPD). EPP is normally an inherited disorder characterized by photosensitivity that starts in early childhood and results from overproduction of protoporphyrin secondary to ferrochelatase (FECH) deficiency. Severe liver disease occurs in 1% to 2% of patients. Here we report that severe photosensitivity and cholestatic liver disease in a patient with a myeloproliferative disorder was caused by excess protoporphyrin production from a clone of hematopoietic cells in which one FECH allele had been deleted. Our observations suggest that the usual explanation for the association of late-onset EPP with MPD and MDS is acquired somatic mutation of one FECH allele in bone marrow and show for the first time that the consequent overproduction of protoporphyrin may be severe enough to cause acute liver damage.

Liver transplantation for erythropoietic protoporphyria liver disease

In erythropoietic protoporphyria (EPP), there is excessive production of protoporphyrin, primarily in the bone marrow, resulting in increased biliary excretion of this heme precursor. Some patients will develop progressive liver disease that may ultimately require liver transplantation. However, excessive production of protoporphyrin by the bone marrow continues after transplantation, which may cause recurrent disease in the allograft. This study was performed to define post-transplant survival, the risk of recurrent disease, and specific management issues in patients transplanted for EPP liver disease. The patients studied consisted of twelve males and eight females, with an average age of 31 (range, 13-56) years at the time of transplantation. The estimated maximum MELD score prior to transplant was 21 (range, 15-29). Unique complications in the perioperative period were light induced tissue damage in four patients and neuropathy in six, requiring prolonged mechanical ventilation in four. Patient and graft survival rates were 85% at 1 year, 69% at 5 years, and 47% at 10 years. Recurrent EPP liver disease occurred in 11 of 17 patients (65%) who survived more than 2 months. Three patients were retransplanted at 1.8, 12.6, and 14.5 years after the initial transplant for recurrent EPP liver disease. In conclusion, the 5-year patient survival rate in patients transplanted for EPP liver disease is good, but the recurrence of EPP liver disease appears to diminish long term graft and patient survival.

Living donor liver transplantation for pediatric patients with inheritable metabolic disorders

Forty-six pediatric patients who underwent living donor liver transplantation (LDLT) using parental liver grafts for inheritable metabolic disorders (IMD) were evaluated to determine the outcomes of the surgery, decisive factors for post-transplant patient survival and the impact of using donors who were heterozygous for the particular disorder. Disorders included Wilson disease (WD, n = 21), ornithine transcarbamylase deficiency (OTCD, n = 6), tyrosinemia type I (TTI, n = 6), glycogen storage disease (GSD, n = 4), propionic acidemia (PPA, n = 3), methylmalonic acidemia (MMA, n = 2), Crigler-Najjar syndrome type I (CNSI, n = 2), bile acid synthetic defect (BASD, n = 1) and erythropoietic protoporphyria (EPP, n = 1). The post-transplant cumulative patient survival rates were 86.8 and 81.2% at 1 and 5 years, respectively. Post-transplant patient survival and recovery of the growth retardation were significantly better in the liver-oriented diseases (WD, OTCD, TTI, CNSI and BASD) than in the non-liver-oriented diseases (GSD, PPA, MMA and EPP) and pre-transplant growth retardation disadvantageously affected post-transplant outcomes. Although 40 of 46 donors were considered heterozygous for each disorder, neither mortality nor morbidity related to the heterozygosis has been observed. LDLT using parental donors can be recommended as an effective treatment for pediatric patients with IMD. In the non-liver-oriented diseases, however, satisfactory outcomes were not obtained by hepatic replacement alone.

Hemin-activated macrophages home to the pancreas and protect from acute pancreatitis via heme oxygenase-1 induction

Hemin upregulates heme oxygenase-1 (HO-1), a stress-induced enzyme implicated in protection from a variety of injuries while its related isoform HO-2 is constitutively expressed. The role of hemin or HO-1 in the pancreas and their potential modulation of pancreatic injury are unknown. We show that HO-1 is induced in pancreatitis caused by caerulein and more prominently in severe pancreatitis caused by feeding a choline-deficient diet (CDD). Intraperitoneal hemin administration dramatically increases peritoneal and pancreas macrophages that overexpress HO-1 in association with pancreatic induction of the chemoattractants monocyte chemotactic protein-1 and macrophage inflammatory protein-1alpha but not RANTES or macrophage inflammatory protein-2. Hemin administration before CDD feeding protected 8 of 8 mice from lethality while 7 of 16 controls died. Protection is mediated by HO-1-overexpressing macrophages since hemin-primed macrophages home to the pancreas after transfer to naive mice and protect from CDD-induced pancreatitis. Suppression of hemin-primed peritoneal cell HO-1 using HO-1-specific small interfering RNA prior to cell transfer abolishes protection from CDD-induced pancreatitis. Similarly, hemin pretreatment in caerulein-induced pancreatitis reduces serum amylase and lipase, decreases pancreatic trypsin generation, and protects from lung injury. Therefore, hemin-like compounds or hemin-activated macrophages may offer novel therapeutic approaches for preventing acute pancreatitis and its pulmonary complication via upregulation of HO-1.

Red blood cell exchange transfusion in two patients with advanced erythropoietic protoporphyria

BACKGROUND

Erythropoietic protoporphyria (EPP) is a rare, autosomal dominant genetic disorder caused by the decreased or absent activity of ferrochelatase, the final enzyme in the heme biosynthetic pathway. This enzyme defect in peripheral blood progenitor cells leads to the accumulation of protoporphyrin deposits in multiple tissues. Plasmapheresis has been previously reported as an adjunctive therapy for patients with advanced hepatic EPP. Because the concentration of protoporphyrins is severalfold higher inside the red blood cell (RBC) compared to plasma, it was hypothesized that RBC exchange therapy might absorb excess protoporphyrins from the plasma and serve as an effective therapy to reduce protoporphyrin load in patients with advanced hepatic EPP. The effectiveness of RBC exchange plus hematin versus plasmapheresis plus hematin in two patients with advanced hepatic EPP is reported.

STUDY DESIGN AND METHODS

Two patients with advanced hepatic EPP were treated with RBC exchange and plasmapheresis in the setting of recurrent disease in the graft (Patient 1) or preparation for liver transplantation (Patient 2). In vitro studies were performed to test transport of protoporphyrins from patients' plasma to normal RBCs.

RESULTS

Compared with plasmapheresis, RBC exchange was more effective, for the duration of the therapy, in reducing blood levels of protoporphyrins. Liver function tests, however, showed only a modest improvement during therapy. In vitro extracellular protoporphyrin were rapidly adsorbed into normal RBCs.

CONCLUSION

Neither RBC exchange nor plasmapheresis prevented progressive hepatic deterioration in advanced hepatic EPP despite a significant decrease in protoporphyrin levels.